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Posted: September 20, 2016 at 7:07 pm
Genetics is the scientific study of inherited variation. Human genetics, then, is the scientific study of inherited human variation.
Why study human genetics? One reason is simply an interest in better understanding ourselves. As a branch of genetics, human genetics concerns itself with what most of us consider to be the most interesting species on earth: Homo sapiens. But our interest in human genetics does not stop at the boundaries of the species, for what we learn about human genetic variation and its sources and transmission inevitably contributes to our understanding of genetics in general, just as the study of variation in other species informs our understanding of our own.
A second reason for studying human genetics is its practical value for human welfare. In this sense, human genetics is more an applied science than a fundamental science. One benefit of studying human genetic variation is the discovery and description of the genetic contribution to many human diseases. This is an increasingly powerful motivation in light of our growing understanding of the contribution that genes make to the development of diseases such as cancer, heart disease, and diabetes. In fact, society has been willing in the past and continues to be willing to pay significant amounts of money for research in this area, primarily because of its perception that such study has enormous potential to improve human health. This perception, and its realization in the discoveries of the past 20 years, have led to a marked increase in the number of people and organizations involved in human genetics.
This second reason for studying human genetics is related to the first. The desire to develop medical practices that can alleviate the suffering associated with human disease has provided strong support to basic research. Many basic biological phenomena have been discovered and described during the course of investigations into particular disease conditions. A classic example is the knowledge about human sex chromosomes that was gained through the study of patients with sex chromosome abnormalities. A more current example is our rapidly increasing understanding of the mechanisms that regulate cell growth and reproduction, understanding that we have gained primarily through a study of genes that, when mutated, increase the risk of cancer.
Likewise, the results of basic research inform and stimulate research into human disease. For example, the development of recombinant DNA techniques () rapidly transformed the study of human genetics, ultimately allowing scientists to study the detailed structure and functions of individual human genes, as well as to manipulate these genes in a variety of previously unimaginable ways.
Recombinant techniques have transformed the study of human genetics.
A third reason for studying human genetics is that it gives us a powerful tool for understanding and describing human evolution. At one time, data from physical anthropology (including information about skin color, body build, and facial traits) were the only source of information available to scholars interested in tracing human evolutionary history. Today, however, researchers have a wealth of genetic data, including molecular data, to call upon in their work.
Two research approaches were historically important in helping investigators understand the biological basis of heredity. The first of these approaches, transmission genetics, involved crossing organisms and studying the offsprings’ traits to develop hypotheses about the mechanisms of inheritance. This work demonstrated that in some organisms at least, heredity seems to follow a few definite and rather simple rules.
The second approach involved using cytologic techniques to study the machinery and processes of cellular reproduction. This approach laid a solid foundation for the more conceptual understanding of inheritance that developed as a result of transmission genetics. By the early 1900s, cytologists had demonstrated that heredity is the consequence of the genetic continuity of cells by cell division, had identified the gametes as the vehicles that transmit genetic information from one generation to another, and had collected strong evidence for the central role of the nucleus and the chromosomes in heredity.
As important as they were, the techniques of transmission genetics and cytology were not enough to help scientists understand human genetic variation at the level of detail that is now possible. The central advantage that today’s molecular techniques offer is that they allow researchers to study DNA directly. Before the development of these techniques, scientists studying human genetic variation were forced to make inferences about molecular differences from the phenotypes produced by mutant genes. Furthermore, because the genes associated with most single-gene disorders are relatively rare, they could be studied in only a small number of families. Many of the traits associated with these genes also are recessive and so could not be detected in people with heterozygous genotypes. Unlike researchers working with other species, human geneticists are restricted by ethical considerations from performing experimental, “at-will” crosses on human subjects. In addition, human generations are on the order of 20 to 40 years, much too slow to be useful in classic breeding experiments. All of these limitations made identifying and studying genes in humans both tedious and slow.
In the last 50 years, however, beginning with the discovery of the structure of DNA and accelerating significantly with the development of recombinant DNA techniques in the mid-1970s, a growing battery of molecular techniques has made direct study of human DNA a reality. Key among these techniques are restriction analysis and molecular recombination, which allow researchers to cut and rejoin DNA molecules in highly specific and predictable ways; amplification techniques, such as the polymerase chain reaction (PCR), which make it possible to make unlimited copies of any fragment of DNA; hybridization techniques, such as fluorescence in situ hybridization, which allow scientists to compare DNA samples from different sources and to locate specific base sequences within samples; and the automated sequencing techniques that today are allowing workers to sequence the human genome at an unprecedented rate.
On the immediate horizon are even more powerful techniques, techniques that scientists expect will have a formidable impact on the future of both research and clinical genetics. One such technique, DNA chip technology (also called DNA microarray technology), is a revolutionary new tool designed to identify mutations in genes or survey expression of tens of thousands of genes in one experiment.
In one application of this technology, the chip is designed to detect mutations in a particular gene. The DNA microchip consists of a small glass plate encased in plastic. It is manufactured using a process similar to the process used to make computer microchips. On its surface, it contains synthetic single-stranded DNA sequences identical to that of the normal gene and all possible mutations of that gene. To determine whether an individual possesses a mutation in the gene, a scientist first obtains a sample of DNA from the person’s blood, as well as a sample of DNA that does not contain a mutation in that gene. After denaturing, or separating, the DNA samples into single strands and cutting them into smaller, more manageable fragments, the scientist labels the fragments with fluorescent dyes: the person’s DNA with red dye and the normal DNA with green dye. Both sets of labeled DNA are allowed to hybridize, or bind, to the synthetic DNA on the chip. If the person does not have a mutation in the gene, both DNA samples will hybridize equivalently to the chip and the chip will appear uniformly yellow. However, if the person does possess a mutation, the mutant sequence on the chip will hybridize to the patient’s sample, but not to the normal DNA, causing it (the chip) to appear red in that area. The scientist can then examine this area more closely to confirm that a mutation is present.
DNA microarray technology is also allowing scientists to investigate the activity in different cell types of thousands of genes at the same time, an advance that will help researchers determine the complex functional relationships that exist between individual genes. This type of analysis involves placing small snippets of DNA from hundreds or thousands of genes on a single microscope slide, then allowing fluorescently labeled mRNA molecules from a particular cell type to hybridize to them. By measuring the fluorescence of each spot on the slide, scientists can determine how active various genes are in that cell type. Strong fluorescence indicates that many mRNA molecules hybridized to the gene and, therefore, that the gene is very active in that cell type. Conversely, no fluorescence indicates that none of the cell’s mRNA molecules hybridized to the gene and that the gene is inactive in that cell type.
Although these technologies are still relatively new and are being used primarily for research, scientists expect that one day they will have significant clinical applications. For example, DNA chip technology has the potential to significantly reduce the time and expense involved in genetic testing. This technology or others like it may one day help make it possible to define an individual’s risk of developing many types of hereditary cancer as well as other common disorders, such as heart disease and diabetes. Likewise, scientists may one day be able to classify human cancers based on the patterns of gene activity in the tumor cells and then be able to design treatment strategies that are targeted directly to each specific type of cancer.
Homo sapiens is a relatively young species and has not had as much time to accumulate genetic variation as have the vast majority of species on earth, most of which predate humans by enormous expanses of time. Nonetheless, there is considerable genetic variation in our species. The human genome comprises about 3 109 base pairs of DNA, and the extent of human genetic variation is such that no two humans, save identical twins, ever have been or will be genetically identical. Between any two humans, the amount of genetic variationbiochemical individualityis about .1 percent. This means that about one base pair out of every 1,000 will be different between any two individuals. Any two (diploid) people have about 6 106 base pairs that are different, an important reason for the development of automated procedures to analyze genetic variation.
The most common polymorphisms (or genetic differences) in the human genome are single base-pair differences. Scientists call these differences SNPs, for single-nucleotide polymorphisms. When two different haploid genomes are compared, SNPs occur, on average, about every 1,000 bases. Other types of polymorphismsfor example, differences in copy number, insertions, deletions, duplications, and rearrangementsalso occur, but much less frequently.
Notwithstanding the genetic differences between individuals, all humans have a great deal of their genetic information in common. These similarities help define us as a species. Furthermore, genetic variation around the world is distributed in a rather continuous manner; there are no sharp, discontinuous boundaries between human population groups. In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations (). That is, research reveals that Homo sapiens is one continuously variable, interbreeding species. Ongoing investigation of human genetic variation has even led biologists and physical anthropologists to rethink traditional notions of human racial groups. The amount of genetic variation between these traditional classifications actually falls below the level that taxonomists use to designate subspecies, the taxonomic category for other species that corresponds to the designation of race in Homo sapiens. This finding has caused some biologists to call the validity of race as a biological construct into serious question.
Most variation occurs within populations.
Analysis of human genetic variation also confirms that humans share much of their genetic information with the rest of the natural worldan indication of the relatedness of all life by descent with modification from common ancestors. The highly conserved nature of many genetic regions across considerable evolutionary distance is especially obvious in genes related to development. For example, mutations in the patched gene produce developmental abnormalities in Drosophila, and mutations in the patched homolog in humans produce analogous structural deformities in the developing human embryo.
Geneticists have used the reality of evolutionary conservation to detect genetic variations associated with some cancers. For example, mutations in the genes responsible for repair of DNA mismatches that arise during DNA replication are associated with one form of colon cancer. These mismatched repair genes are conserved in evolutionary history all the way back to the bacterium Escherichia coli, where the genes are designated Mutl and Muts. Geneticists suspected that this form of colon cancer was associated with a failure of mismatch repair, and they used the known sequences from the E. coli genes to probe the human genome for homologous sequences. This work led ultimately to the identification of a gene that is associated with increased risk for colon cancer.
Almost all human genetic variation is relatively insignificant biologically; that is, it has no adaptive significance. Some variation (for example, a neutral mutation) alters the amino acid sequence of the resulting protein but produces no detectable change in its function. Other variation (for example, a silent mutation) does not even change the amino acid sequence. Furthermore, only a small percentage of the DNA sequences in the human genome are coding sequences (sequences that are ultimately translated into protein) or regulatory sequences (sequences that can influence the level, timing, and tissue specificity of gene expression). Differences that occur elsewhere in the DNAin the vast majority of the DNA that has no known functionhave no impact.
Some genetic variation, however, can be positive, providing an advantage in changing environments. The classic example from the high school biology curriculum is the mutation for sickle hemoglobin, which in the heterozygous state provides a selective advantage in areas where malaria is endemic.
More recent examples include mutations in the CCR5 gene that appear to provide protection against AIDS. The CCR5 gene encodes a protein on the surface of human immune cells. HIV, the virus that causes AIDS, infects immune cells by binding to this protein and another protein on the surface of those cells. Mutations in the CCR5 gene that alter its level of expression or the structure of the resulting protein can decrease HIV infection. Early research on one genetic variant indicates that it may have risen to high frequency in Northern Europe about 700 years ago, at about the time of the European epidemic of bubonic plague. This finding has led some scientists to hypothesize that the CCR5 mutation may have provided protection against infection by Yersinia pestis, the bacterium that causes plague. The fact that HIV and Y. pestis both infect macrophages supports the argument for selective advantage of this genetic variant.
The sickle cell and AIDS/plague stories remind us that the biological significance of genetic variation depends on the environment in which genes are expressed. It also reminds us that differential selection and evolution would not proceed in the absence of genetic variation within a species.
Some genetic variation, of course, is associated with disease, as classic single-gene disorders such as sickle cell disease, cystic fibrosis, and Duchenne muscular dystrophy remind us. Increasingly, research also is uncovering genetic variations associated with the more common diseases that are among the major causes of sickness and death in developed countriesdiseases such as heart disease, cancer, diabetes, and psychiatric disorders such as schizophrenia and bipolar disease (manic-depression). Whereas disorders such as cystic fibrosis or Huntington disease result from the effects of mutation in a single gene and are evident in virtually all environments, the more common diseases result from the interaction of multiple genes and environmental variables. Such diseases therefore are termed polygenic and multifactorial. In fact, the vast majority of human traits, diseases or otherwise, are multifactorial.
The genetic distinctions between relatively rare single-gene disorders and the more common multifactorial diseases are significant. Genetic variations that underlie single-gene disorders generally are relatively recent, and they often have a major, detrimental impact, disrupting homeostasis in significant ways. Such disorders also generally exact their toll early in life, often before the end of childhood. In contrast, the genetic variations that underlie common, multifactorial diseases generally are of older origin and have a smaller, more gradual effect on homeostasis. They also generally have their onset in adulthood. The last two characteristics make the ability to detect genetic variations that predispose/increase risk of common diseases especially valuable because people have time to modify their behavior in ways that can reduce the likelihood that the disease will develop, even against a background of genetic predisposition.
As noted earlier, one of the benefits of understanding human genetic variation is its practical value for understanding and promoting health and for understanding and combating disease. We probably cannot overestimate the importance of this benefit. First, as shows, virtually every human disease has a genetic component. In some diseases, such as Huntington disease, Tay-Sachs disease, and cystic fibrosis, this component is very large. In other diseases, such as cancer, diabetes, and heart disease, the genetic component is more modest. In fact, we do not typically think of these diseases as “genetic diseases,” because we inherit not the certainty of developing a disease, but only a predisposition to developing it.
Virtually all human diseases, except perhaps trauma, have a genetic component.
In still other diseases, the genetic component is very small. The crucial point, however, is that it is there. Even infectious diseases, diseases that we have traditionally placed in a completely different category than genetic disorders, have a real, albeit small, genetic component. For example, as the CCR5 example described earlier illustrates, even AIDS is influenced by a person’s genotype. In fact, some people appear to have genetic resistance to HIV infection as a result of carrying a variant of the CCR5 gene.
Second, each of us is at some genetic risk, and therefore can benefit, at least theoretically, from the progress scientists are making in understanding and learning how to respond to these risks. Scientists estimate that each of us carries between 5 and 50 mutations that carry some risk for disease or disability. Some of us may not experience negative consequences from the mutations we carry, either because we do not live long enough for it to happen or because we may not be exposed to the relevant environmental triggers. The reality, however, is that the potential for negative consequences from our genes exists for each of us.
How is modern genetics helping us address the challenge of human disease? As shows, modern genetic analysis of a human disease begins with mapping and cloning the associated gene or genes. Some of the earliest disease genes to be mapped and cloned were the genes associated with Duchenne muscular dystrophy, retinoblastoma, and cystic fibrosis. More recently, scientists have announced the cloning of genes for breast cancer, diabetes, and Parkinson disease.
Mapping and cloning a gene can lead to strategies that reduce the risk of disease (preventive medicine); guidelines for prescribing drugs based on a person’s genotype (pharmacogenomics); procedures that alter the affected gene (gene therapy); or drugs (more…)
As also shows, mapping and cloning a disease-related gene opens the way for the development of a variety of new health care strategies. At one end of the spectrum are genetic tests intended to identify people at increased risk for the disease and recognize genotypic differences that have implications for effective treatment. At the other end are new drug and gene therapies that specifically target the biochemical mechanisms that underlie the disease symptoms or even replace, manipulate, or supplement nonfunctional genes with functional ones. Indeed, as suggests, we are entering the era of molecular medicine.
Genetic testing is not a new health care strategy. Newborn screening for diseases like PKU has been going on for 30 years in many states. Nevertheless, the remarkable progress scientists are making in mapping and cloning human disease genes brings with it the prospect for the development of more genetic tests in the future. The availability of such tests can have a significant impact on the way the public perceives a particular disease and can also change the pattern of care that people in affected families might seek and receive. For example, the identification of the BRCA1 and BRCA2 genes and the demonstration that particular variants of these genes are associated with an increased risk of breast and ovarian cancer have paved the way for the development of guidelines and protocols for testing individuals with a family history of these diseases. BRCA1, located on the long arm of chromosome 17, was the first to be isolated, and variants of this gene account for about 50 percent of all inherited breast cancer, or about 5 percent of all breast cancer. Variants of BRCA2, located on the long arm of chromosome 13, appear to account for about 30 to 40 percent of all inherited breast cancer. Variants of these genes also increase slightly the risk for men of developing breast, prostate, or possibly other cancers.
Scientists estimate that hundreds of thousands of women in the United States have 1 of hundreds of significant mutations already detected in the BRCA1 gene. For a woman with a family history of breast cancer, the knowledge that she carries one of the variants of BRCA1 or BRCA2 associated with increased risk can be important information. If she does carry one of these variants, she and her physician can consider several changes in her health care, such as increasing the frequency of physical examinations; introducing mammography at an earlier age; and even having prophylactic mastectomy. In the future, drugs may also be available that decrease the risk of developing breast cancer.
The ability to test for the presence in individuals of particular gene variants is also changing the way drugs are prescribed and developed. A rapidly growing field known as pharmacogenomics focuses on crucial genetic differences that cause drugs to work well in some people and less well, or with dangerous adverse reactions, in others. For example, researchers investigating Alzheimer disease have found that the way patients respond to drug treatment can depend on which of three genetic variants of the ApoE (Apolipoprotein E) gene a person carries. Likewise, some of the variability in children’s responses to therapeutic doses of albuterol, a drug used to treat asthma, was recently linked to genotypic differences in the beta-2-adrenergic receptor. Because beta-2-adrenergic receptor agonists (of which albuterol is one) are the most widely used agents in the treatment of asthma, these results may have profound implications for understanding the genetic factors that determine an individual’s response to asthma therapy.
Experts predict that increasingly in the future, physicians will use genetic tests to match drugs to an individual patient’s body chemistry, so that the safest and most effective drugs and dosages can be prescribed. After identifying the genotypes that determine individual responses to particular drugs, pharmaceutical companies also likely will set out to develop new, highly specific drugs and revive older ones whose effects seemed in the past too unpredictable to be of clinical value.
Knowledge of the molecular structure of disease-related genes also is changing the way researchers approach developing new drugs. A striking example followed the discovery in 1989 of the gene associated with cystic fibrosis (CF). Researchers began to study the function of the normal and defective proteins involved in order to understand the biochemical consequences of the gene’s variant forms and to develop new treatment strategies based on that knowledge. The normal protein, called CFTR for cystic fibrosis transmembrane conductance regulator, is embedded in the membranes of several cell types in the body, where it serves as a channel, transporting chloride ions out of the cells. In CF patients, depending on the particular mutation the individual carries, the CFTR protein may be reduced or missing from the cell membrane, or may be present but not function properly. In some mutations, synthesis of CFTR protein is interrupted, and the cells produce no CFTR molecules at all.
Although all of the mutations associated with CF impair chloride transport, the consequences for patients with different mutations vary. For example, patients with mutations causing absent or markedly reduced CFTR protein may have more severe disease than patients with mutations in which CFTR is present but has altered function. The different mutations also suggest different treatment strategies. For example, the most common CF-related mutation (called delta F508) leads to the production of protein molecules (called delta F508 CFTR) that are misprocessed and are degraded prematurely before they reach the cell membrane. This finding suggests that drug treatments that would enhance transport of the defective delta F508 protein to the cell membrane or prevent its degradation could yield important benefits for patients with delta F508 CFTR.
Finally, the identification, cloning, and sequencing of a disease-related gene can open the door to the development of strategies for treating the disease using the instructions encoded in the gene itself. Collectively referred to as gene therapy, these strategies typically involve adding a copy of the normal variant of a disease-related gene to a patient’s cells. The most familiar examples of this type of gene therapy are cases in which researchers use a vector to introduce the normal variant of a disease-related gene into a patient’s cells and then return those cells to the patient’s body to provide the function that was missing. This strategy was first used in the early 1990s to introduce the normal allele of the adenosine deaminase (ADA) gene into the body of a little girl who had been born with ADA deficiency. In this disease, an abnormal variant of the ADA gene fails to make adenosine deaminase, a protein that is required for the correct functioning of T-lymphocytes.
Although researchers are continuing to refine this general approach to gene therapy, they also are developing new approaches. For example, scientists hope that one very new strategy, called chimeraplasty, may one day be used to actually correct genetic defects that involve only a single base change. Chimeraplasty uses specially synthesized molecules that base pair with a patient’s DNA and stimulate the cell’s normal DNA repair mechanisms to remove the incorrect base and substitute the correct one. At this point, chimeraplasty is still in early development and the first clinical trials are about to get underway.
Yet another approach to gene therapy involves providing new or altered functions to a cell through the introduction of new genetic information. For example, recent experiments have demonstrated that it is possible, under carefully controlled experimental conditions, to introduce genetic information into cancer cells that will alter their metabolism so that they commit suicide when exposed to a normally innocuous environmental trigger. Researchers are also using similar experiments to investigate the feasibility of introducing genetic changes into cells that will make them immune to infection by HIV. Although this research is currently being done only in nonhuman primates, it may eventually benefit patients infected with HIV.
As indicates, the Human Genome Project (HGP) has significantly accelerated the pace of both the discovery of human genes and the development of new health care strategies based on a knowledge of a gene’s structure and function. The new knowledge and technologies emerging from HGP-related research also are reducing the cost of finding human genes. For example, the search for the gene associated with cystic fibrosis, which ended in 1989, before the inception of the HGP, required more than eight years and $50 million. In contrast, finding a gene associated with a Mendelian disorder now can be accomplished in less than a year at a cost of approximately $100,000.
The last few years of research into human genetic variation also have seen a gradual transition from a primary focus on genes associated with single-gene disorders, which are relatively rare in the human population, to an increasing focus on genes associated with multifactorial diseases. Because these diseases are not rare, we can expect that this work will affect many more people. Understanding the genetic and environmental bases for these multifactorial diseases also will lead to increased testing and the development of new interventions that likely will have an enormous effect on the practice of medicine in the next century.
What are the implications of using our growing knowledge of human genetic variation to improve personal and public health? As noted earlier, the rapid pace of the discovery of genetic factors in disease has improved our ability to predict the risk of disease in asymptomatic individuals. We have learned how to prevent the manifestations of some of these diseases, and we are developing the capacity to treat others.
Yet, much remains unknown about the benefits and risks of building an understanding of human genetic variation at the molecular level. While this information would have the potential to dramatically improve human health, the architects of the HGP realized that it also would raise a number of complex ethical, legal, and social issues. Thus, in 1990 they established the Ethical, Legal, and Social Implications (ELSI) program to anticipate and address the ethical, legal, and social issues that arise from human genetic research. This program, perhaps more than any other, has focused public attention, as well as the attention of educators, on the increasing importance of preparing citizens to understand and contribute to the ongoing public dialogue related to advances in genetics.
Ethics is the study of right and wrong, good and bad. It has to do with the actions and character of individuals, families, communities, institutions, and societies. During the last two and one-half millennia, Western philosophy has developed a variety of powerful methods and a reliable set of concepts and technical terms for studying and talking about the ethical life. Generally speaking, we apply the terms “right” and “good” to those actions and qualities that foster the interests of individuals, families, communities, institutions, and society. Here, an “interest” refers to a participant’s share or participation in a situation. The terms “wrong” or “bad” apply to those actions and qualities that impair interests.
Ethical considerations are complex, multifaceted, and raise many questions. Often, there are competing, well-reasoned answers to questions about what is right and wrong, and good and bad, about an individual’s or group’s conduct or actions. Typically, these answers all involve appeals to values. A value is something that has significance or worth in a given situation. One of the exciting events to witness in any discussion in ethics is the varying ways in which the individuals involved assign values to things, persons, and states of affairs. Examples of values that students may appeal to in a discussion about ethics include autonomy, freedom, privacy, sanctity of life, religion, protecting another from harm, promoting another’s good, justice, fairness, relationships, scientific knowledge, and technological progress.
Acknowledging the complex, multifaceted nature of ethical discussions is not to suggest that “anything goes.” Experts generally agree on the following features of ethics. First, ethics is a process of rational inquiry. It involves posing clearly formulated questions and seeking well-reasoned answers to those questions. For example, we can ask questions about an individual’s right to privacy regarding personal genetic information; we also can ask questions about the appropriateness of particular uses of gene therapy. Well-reasoned answers to such questions constitute arguments. Ethical analysis and argument, then, result from successful ethical inquiry.
Second, ethics requires a solid foundation of information and rigorous interpretation of that information. For example, one must have a solid understanding of biology to evaluate the recent decision by the Icelandic government to create a database that will contain extensive genetic and medical information about the country’s citizens. A knowledge of science also is needed to discuss the ethics of genetic screening or of germ-line gene therapy. Ethics is not strictly a theoretical discipline but is concerned in vital ways with practical matters.
Third, discussions of ethical issues often lead to the identification of very different answers to questions about what is right and wrong and good and bad. This is especially true in a society such as our own, which is characterized by a diversity of perspectives and values. Consider, for example, the question of whether adolescents should be tested for late-onset genetic conditions. Genetic testing centers routinely withhold genetic tests for Huntington disease (HD) from asymptomatic patients under the age of 18. The rationale is that the condition expresses itself later in life and, at present, treatment is unavailable. Therefore, there is no immediate, physical health benefit for a minor from a specific diagnosis based on genetic testing. In addition, there is concern about the psychological effects of knowing that later in life one will get a debilitating, life-threatening condition. Teenagers can wait until they are adults to decide what and when they would like to know. In response, some argue that many adolescents and young children do have sufficient autonomy in consent and decision making and may wish to know their future. Others argue that parents should have the right to have their children tested, because parents make many other medical decisions on behalf of their children. This example illustrates how the tools of ethics can bring clarity and rigor to discussions involving values.
One of the goals of this module is to help students see how understanding science can help individuals and society make reasoned decisions about issues related to genetics and health. Activity 5, Making Decisions in the Face of Uncertainty, presents students with a case of a woman who is concerned that she may carry an altered gene that predisposes her to breast and ovarian cancer. The woman is faced with numerous decisions, which students also consider. Thus, the focus of Activity 5 is prudential decision making, which involves the ability to avoid unnecessary risk when it is uncertain whether an event actually will occur. By completing the activity, students understand that uncertainty is often a feature of questions related to genetics and health, because our knowledge of genetics is incomplete and constantly changing. In addition, students see that making decisions about an uncertain future is complex. In simple terms, students have to ask themselves, “How bad is the outcome and how likely is it to occur?” When the issues are weighed, different outcomes are possible, depending on one’s estimate of the incidence of the occurrence and how much burden one attaches to the risk.
Clearly, science as well as ethics play important roles in helping individuals make choices about individual and public health. Science provides evidence that can help us understand and treat human disease, illness, deformity, and dysfunction. And ethics provides a framework for identifying and clarifying values and the choices that flow from these values. But the relationships between scientific information and human choices, and between choices and behaviors, are not straightforward. In other words, human choice allows individuals to choose against sound knowledge, and choice does not require action.
Nevertheless, it is increasingly difficult to deny the claims of science. We are continually presented with great amounts of relevant scientific and medical knowledge that is publicly accessible. As a consequence, we can think about the relationships between knowledge, choice, behavior, and human welfare in the following ways:
One of the goals of this module is to encourage students to think in terms of these relationships, now and as they grow older.
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The following glossary was modified from the glossary on the National Human Genome Research Institute’s Web site, available at http://www.nhgri.nih.gov.
One of the variant forms of a gene at a particular locus, or location, on a chromosome. Different alleles produce variation in inherited characteristics such as hair color or blood type. In an individual, one form of the allele (the dominant one) may be expressed more than another form (the recessive one).
One of 20 different kinds of small molecules that link together in long chains to form proteins. Amino acids are referred to as the “building blocks” of proteins.
Gene on one of the autosomes that, if present, will almost always produce a specific trait or disease. The chance of passing the gene (and therefore the disease) to children is 50-50 in each pregnancy.
Chromosome other than a sex chromosome. Humans have 22 pairs of autosomes.
Two bases that form a “rung of the DNA ladder.” The bases are the “letters” that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.
Defect present at birth, whether caused by mutant genes or by prenatal events that are not genetic.
First breast cancer genes to be identified. Mutated forms of these genes are believed to be responsible for about one-half the cases of inherited breast cancer, especially those that occur in younger women, and also to increase a woman’s risk for ovarian cancer. Both are tumor suppressor genes.
Diseases in which abnormal cells divide and grow unchecked. Cancer can spread from its original site to other parts of the body and can be fatal if not treated adequately.
Gene, located in a chromosome region suspected of being involved in a disease, whose protein product suggests that it could be the disease gene in question.
Mutation that confers immunity to infection by HIV. The mutation alters the structure of a receptor on the surface of macrophages such that HIV cannot enter the cell.
Collection of DNA sequences generated from mRNA sequences. This type of library contains only protein-coding DNA (genes) and does not include any noncoding DNA.
Basic unit of any living organism. It is a small, watery, compartment filled with chemicals and a complete copy of the organism’s genome.
One of the thread like “packages” of genes and other DNA in the nucleus of a cell. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two sex chromosomes. Each parent contributes one chromosome to each pair, so children get one-half of their chromosomes from their mothers and one-half from their fathers.
Process of making copies of a specific piece of DNA, usually a gene. When geneticists speak of cloning, they do not mean the process of making genetically identical copies of an entire organism.
Three bases in a DNA or RNA sequence that specify a single amino acid.
Hereditary disease whose symptoms usually appear shortly after birth. They include faulty digestion, breathing difficulties and respiratory infections due to mucus accumulation, and excessive loss of salt in sweat. In the past, cystic fibrosis was almost always fatal in childhood, but treatment is now so improved that patients commonly live to their 20s and beyond.
Visual appearance of a chromo some when stained and examined under a microscope. Particularly important are visually distinct regions, called light and dark bands, that give each of the chromosomes a unique appearance. This feature allows a person’s chromosomes to be studied in a clinical test known as a karyotype, which allows scientists to look for chromosomal alterations.
Particular kind of mutation: loss of a piece of DNA from a chromosome. Deletion of a gene or part of a gene can lead to a disease or abnormality.
Chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms.
Number of chromosomes in most cells except the gametes. In humans, the diploid number is 46.
Technology that identifies mutations in genes. It uses small glass plates that contain synthetic single-stranded DNA sequences identical to those of a normal gene.
Process by which the DNA double helix unwinds and makes an exact copy of itself.
Determining the exact order of the base pairs in a segment of DNA.
Gene that almost always results in a specific physical characteristic (for example, a disease) even though the patient’s genome possesses only one copy. With a dominant gene, the chance of passing on the gene (and therefore the disease) to children is 50-50 in each pregnancy.
Structural arrangement of DNA, which looks something like an immensely long ladder twisted into a helix, or coil. The sides of the “ladder” are formed by a backbone of sugar and phosphate molecules, and the “rungs” consist of nucleotide bases joined weakly in the middle by hydrogen bonds.
Particular kind of mutation: production of one or more copies of any piece of DNA, including a gene or even an entire chromosome.
Process in which molecules (such as proteins, DNA, or RNA fragments) can be separated according to size and electrical charge by applying an electric current to them. The current forces the molecules through pores in a thin layer of gel, a firm, jellylike substance. The gel can be made so that its pores are just the right dimensions for separating molecules within a specific range of sizes and shapes. Smaller fragments usually travel further than large ones. The process is sometimes called gel electrophoresis.
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Posted: September 18, 2016 at 8:13 am
This breathtaking new image from the Hubble Space Telescope captures electric-blue wisps of gas and bright stars in the early stages of birth.
ESA/Hubble & NASA
A spectacular new image captured by the Hubble Space Telescope shows bright-blue wisps of glowing gas and hot, sparkling, young stars within a satellite dwarf galaxy known as the Large Magellanic Cloud (LMC).
The LMC is one of the smallersatellite galaxies that orbit the Milky Way, and its among a collection of galaxies known as the local group. It is one of the closest galaxies to Earth, at about 163,000 light-years away.
Astronomers revisit iconic nebula for a different look from 20 years ago
This dazzling new Hubble image peers into a stellar nursery known as N159, which measures more than 150 light-years across and houses many hot, newborn stars. [Hubble in Pictures: Astronomers Top Picks (Photos)]
These stars are emitting intense ultraviolet light, which causes nearby hydrogen gas to glow, and torrential stellar winds, which are carving out ridges, arcs and filaments from the surrounding material, Hubble researcherssaid in a statementwhen debuting the photo.
Within this stellar nursery lies a butterfly-shaped cosmic cloud known as the Papillon Nebula. The region consists of vast amounts of dense gas that give way to the birth of new stars.
N159 is located south of the Tarantula Nebula, which is designated heic1402 another region known for massive star birth within the LMC. The Tarantula Nebula is located 170,000 light-years from Earth and is believed tohouse hundreds of thousands of stars. Inside the Tarantula Nebula lies an incredibly bright region known as 30 Doradus, which is considered a hotspot for star formation, according to the statement, released jointly by NASA and the European Space Agency.
This beautiful new image, one of many taken by the Hubble telescope, was captured using Hubbles Advanced Camera for Surveys.
Follow Samantha Mathewson@Sam_Ashley13. Follow us@Spacedotcom,FacebookandGoogle+. Original article onSpace.com.
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Posted: September 10, 2016 at 5:35 am
Alternate Title: betting
Gambling, the betting or staking of something of value, with consciousness of risk and hope of gain, on the outcome of a game, a contest, or an uncertain event whose result may be determined by chance or accident or have an unexpected result by reason of the bettors miscalculation.
The outcomes of gambling games may be determined by chance alone, as in the purely random activity of a tossed pair of dice or of the ball on a roulette wheel, or by physical skill, training, or prowess in athletic contests, or by a combination of strategy and chance. The rules by which gambling games are played sometimes serve to confuse the relationship between the components of the game, which depend on skill and chance, so that some players may be able to manipulate the game to serve their own interests. Thus, knowledge of the game is useful for playing poker or betting on horse racing but is of very little use for purchasing lottery tickets or playing slot machines.
A gambler may participate in the game itself while betting on its outcome (card games, craps), or he may be prevented from any active participation in an event in which he has a stake (professional athletics, lotteries). Some games are dull or nearly meaningless without the accompanying betting activity and are rarely played unless wagering occurs (coin tossing, poker, dice games, lotteries). In other games betting is not intrinsically part of the game, and the association is merely conventional and not necessary to the performance of the game itself (horse racing, football pools). Commercial establishments such as casinos and racetracks may organize gambling when a portion of the money wagered by patrons can be easily acquired by participation as a favoured party in the game, by rental of space, or by withdrawing a portion of the betting pool. Some activities of very large scale (horse racing, lotteries) usually require commercial and professional organizations to present and maintain them efficiently.
A rough estimate of the amount of money legally wagered annually in the world is about $10 trillion (illegal gambling may exceed even this figure). In terms of total turnover, lotteries are the leading form of gambling worldwide. State-licensed or state-operated lotteries expanded rapidly in Europe and the United States during the late 20th century and are widely distributed throughout most of the world. Organized football (soccer) pools can be found in nearly all European countries, several South American countries, Australia, and a few African and Asian countries. Most of these countries also offer either state-organized or state-licensed wagering on other sporting events.
Betting on horse racing is a leading form of gambling in English-speaking countries and in France. It also exists in many other countries. Wherever horse racing is popular, it has usually become a major business, with its own newspapers and other periodicals, extensive statistical services, self-styled experts who sell advice on how to bet, and sophisticated communication networks that furnish information to betting centres, bookmakers and their employees, and workers involved with the care and breeding of horses. The same is true, to a smaller extent, of dog racing. The emergence of satellite broadcasting technology has led to the creation of so-called off-track betting facilities, in which bettors watch live telecasts at locations away from the racetrack.
Casinos or gambling houses have existed at least since the 17th century. In the 20th century they became commonplace and assumed almost a uniform character throughout the world. In Europe and South America they are permitted at many or most holiday resorts but not always in cities. In the United States casinos were for many years legal only in Nevada and New Jersey and, by special license, in Puerto Rico, but most other states now allow casino gambling, and betting facilities operate clandestinely throughout the country, often through corruption of political authorities. Roulette is one of the principal gambling games in casinos throughout France and Monaco and is popular throughout the world. Craps is the principal dice game at most American casinos. Slot and video poker machines are a mainstay of casinos in the United States and Europe and also are found in thousands of private clubs, restaurants, and other establishments; they are also common in Australia. Among the card games played at casinos, baccarat, in its popular form chemin de fer, has remained a principal gambling game in Great Britain and in the continental casinos most often patronized by the English at Deauville, Biarritz, and the Riviera resorts. Faro, at one time the principal gambling game in the United States, has become obsolete. Blackjack is the principal card game in American casinos. The French card game trente et quarante (or rouge et noir) is played at Monte-Carlo and a few other continental casinos. Many other games may also be found in some casinosfor example, sic bo, fan-tan, and pai-gow poker in Asia and local games such as boule, banca francesa, and kalooki in Europe.
At the start of the 21st century, poker exploded in popularity, principally through the high visibility of poker tournaments broadcast on television and the proliferation of Internet playing venues. Another growing form of Internet gambling is the so-called betting exchangesInternet Web sites on which players make wagers with one another, with the Web site taking a small cut of each wager in exchange for organizing and handling the transaction.
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In a wide sense of the word, stock markets may also be considered a form of gambling, albeit one in which skill and knowledge on the part of the bettors play a considerable part. This also goes for insurance; paying the premium on ones life insurance is, in effect, a bet that one will die within a specified time. If one wins (dies), the win is paid out to ones relatives, and if one loses (survives the specified time), the wager (premium) is kept by the insurance company, which acts as a bookmaker and sets the odds (payout ratios) according to actuarial data. These two forms of gambling are considered beneficial to society, the former acquiring venture capital and the latter spreading statistical risks.
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Events or outcomes that are equally probable have an equal chance of occurring in each instance. In games of pure chance, each instance is a completely independent one; that is, each play has the same probability as each of the others of producing a given outcome. Probability statements apply in practice to a long series of events but not to individual ones. The law of large numbers is an expression of the fact that the ratios predicted by probability statements are increasingly accurate as the number of events increases, but the absolute number of outcomes of a particular type departs from expectation with increasing frequency as the number of repetitions increases. It is the ratios that are accurately predictable, not the individual events or precise totals.
The probability of a favourable outcome among all possibilities can be expressed: probability (p) equals the total number of favourable outcomes (f) divided by the total number of possibilities (t), or p=f/t. But this holds only in situations governed by chance alone. In a game of tossing two dice, for example, the total number of possible outcomes is 36 (each of six sides of one die combined with each of six sides of the other), and the number of ways to make, say, a seven is six (made by throwing 1 and 6, 2 and 5, 3 and 4, 4 and 3, 5 and 2, or 6 and 1); therefore, the probability of throwing a seven is 6/36, or 1/6.
In most gambling games it is customary to express the idea of probability in terms of odds against winning. This is simply the ratio of the unfavourable possibilities to the favourable ones. Because the probability of throwing a seven is 1/6, on average one throw in six would be favourable and five would not; the odds against throwing a seven are therefore 5 to 1. The probability of getting heads in a toss of a coin is 1/2; the odds are 1 to 1, called even. Care must be used in interpreting the phrase on average, which applies most accurately to a large number of cases and is not useful in individual instances. A common gamblers fallacy, called the doctrine of the maturity of the chances (or the Monte-Carlo fallacy), falsely assumes that each play in a game of chance is dependent on the others and that a series of outcomes of one sort should be balanced in the short run by the other possibilities. A number of systems have been invented by gamblers largely on the basis of this fallacy; casino operators are happy to encourage the use of such systems and to exploit any gamblers neglect of the strict rules of probability and independent plays. An interesting example of a game where each play is dependent on previous plays, however, is blackjack, where cards already dealt from the dealing shoe affect the composition of the remaining cards; for example, if all of the aces (worth 1 or 11 points) have been dealt, it is no longer possible to achieve a natural (a 21 with two cards). This fact forms the basis for some systems where it is possible to overcome the house advantage.
In some games an advantage may go to the dealer, the banker (the individual who collects and redistributes the stakes), or some other participant. Therefore, not all players have equal chances to win or equal payoffs. This inequality may be corrected by rotating the players among the positions in the game. Commercial gambling operators, however, usually make their profits by regularly occupying an advantaged position as the dealer, or they may charge money for the opportunity to play or subtract a proportion of money from the wagers on each play. In the dice game of crapswhich is among the major casino games offering the gambler the most favourable oddsthe casino returns to winners from 3/5 of 1 percent to 27 percent less than the fair odds, depending on the type of bet made. Depending on the bet, the house advantage (vigorish) for roulette in American casinos varies from about 5.26 to 7.89 percent, and in European casinos it varies from 1.35 to 2.7 percent. The house must always win in the long run. Some casinos also add rules that enhance their profits, especially rules that limit the amounts that may be staked under certain circumstances.
Many gambling games include elements of physical skill or strategy as well as of chance. The game of poker, like most other card games, is a mixture of chance and strategy that also involves a considerable amount of psychology. Betting on horse racing or athletic contests involves the assessment of a contestants physical capacity and the use of other evaluative skills. In order to ensure that chance is allowed to play a major role in determining the outcomes of such games, weights, handicaps, or other correctives may be introduced in certain cases to give the contestants approximately equal opportunities to win, and adjustments may be made in the payoffs so that the probabilities of success and the magnitudes of the payoffs are put in inverse proportion to each other. Pari-mutuel pools in horse-race betting, for example, reflect the chances of various horses to win as anticipated by the players. The individual payoffs are large for those bettors whose winning horses are backed by relatively few bettors and small if the winners are backed by a relatively large proportion of the bettors; the more popular the choice, the lower the individual payoff. The same holds true for betting with bookmakers on athletic contests (illegal in most of the United States but legal in England). Bookmakers ordinarily accept bets on the outcome of what is regarded as an uneven match by requiring the side more likely to win to score more than a simple majority of points; this procedure is known as setting a point spread. In a game of American or Canadian football, for example, the more highly regarded team would have to win by, say, more than 10 points to yield an even payoff to its backers.
Unhappily, these procedures for maintaining the influence of chance can be interfered with; cheating is possible and reasonably easy in most gambling games. Much of the stigma attached to gambling has resulted from the dishonesty of some of its promoters and players, and a large proportion of modern gambling legislation is written to control cheating. More laws have been oriented to efforts by governments to derive tax revenues from gambling than to control cheating, however.
Gambling is one of mankinds oldest activities, as evidenced by writings and equipment found in tombs and other places. It was regulated, which as a rule meant severely curtailed, in the laws of ancient China and Rome as well as in the Jewish Talmud and by Islam and Buddhism, and in ancient Egypt inveterate gamblers could be sentenced to forced labour in the quarries. The origin of gambling is considered to be divinatory: by casting marked sticks and other objects and interpreting the outcome, man sought knowledge of the future and the intentions of the gods. From this it was a very short step to betting on the outcome of the throws. The Bible contains many references to the casting of lots to divide property. One well-known instance is the casting of lots by Roman guards (which in all likelihood meant that they threw knucklebones) for the garment of Jesus during the Crucifixion. This is mentioned in all four of the Gospels and has been used for centuries as a warning example by antigambling crusaders. However, in ancient times casting lots was not considered to be gambling in the modern sense but instead was connected with inevitable destiny, or fate. Anthropologists have also pointed to the fact that gambling is more prevalent in societies where there is a widespread belief in gods and spirits whose benevolence may be sought. The casting of lots, not infrequently dice, has been used in many cultures to dispense justice and point out criminals at trialsin Sweden as late as 1803. The Greek word for justice, dike, comes from a word that means to throw, in the sense of throwing dice.
European history is riddled with edicts, decrees, and encyclicals banning and condemning gambling, which indirectly testify to its popularity in all strata of society. Organized gambling on a larger scale and sanctioned by governments and other authorities in order to raise money began in the 15th century with lotteriesand centuries earlier in China with keno. With the advent of legal gambling houses in the 17th century, mathematicians began to take a serious interest in games with randomizing equipment (such as dice and cards), out of which grew the field of probability theory.
Apart from forerunners in ancient Rome and Greece, organized sanctioned sports betting dates back to the late 18th century. About that time there began a gradual, albeit irregular, shift in the official attitude toward gambling, from considering it a sin to considering it a vice and a human weakness and, finally, to seeing it as a mostly harmless and even entertaining activity. Additionally, the Internet has made many forms of gambling accessible on an unheard-of scale. By the beginning of the 21st century, approximately four out of five people in Western nations gambled at least occasionally. The swelling number of gamblers in the 20th century highlighted the personal and social problem of pathological gambling, in which individuals are unable to control or limit their gambling. During the 1980s and 90s, pathological gambling was recognized by medical authorities in several countries as a cognitive disorder that afflicts slightly more than 1 percent of the population, and various treatment and therapy programs were developed to deal with the problem.
Posted: at 5:33 am
Archeologists believe that Taino people from Cuba and the island of Hispaniola migrated into the southern reaches of the Bahamas in the 11th century.
Those first settlers, known as Lucayans, lived across some scattered islands in the Bahamas when Christopher Columbus arrived in 1492.
There are a few other claims, as well as unsubstantiated opinions, but it is now widely accepted that Christopher Columbus’s first landfall in this ‘New World’ was on the Bahamian island of San Salvador.
Like most other isolated islands, when the indigenous population had not been exposed to the outside world, diseases carried in by European explorers and their crew (unintentionally) decimated the local population; the same was true here for the Taino Indians.
Over the next century, or so, the Taino population was further decimated, as the islands became a major launching base for the Spanish conquest of the Caribbean, and they took the Taino with them as slaves.
Assorted factions from Europe (mainly from England) attempted to settle these islands in the early 17th century. In 1648, English Puritans established the first permanent European settlement on an island they named Eleuthera.
In 1670, England’s King Charles II literally rented the islands for trading purposes to a group of English nobles that were at the time governing British colonies in North America, such as Maryland, Carolina, and New Jersey.
Over the next half century, these low-lying islands, with many places to hide, became a haven for pirates and lawlessness.
To curb those problems, Britain transformed the Bahamas into a crown colony in 1718, one first governed by Woodes Rogers, an English sea captain and privateer.
During the American War of Independence, the British-controlled Bahamas were a frequent target of American naval forces; in fact, American forces once briefly occupied the capital city of Nassau.
After the new country of America gained its independence in the late 1770s, thousands of disgruntled British loyalists (complete with their slaves) moved to the Bahamas.
Across their remaining colonies, mainly because of pressures applied on the home-front, the British abolished the slave trade in 1807. Soon liberated African slavesdominated the population of the Bahamas.
Through the mid 20th century the British remained in control. Then in 1964, the islands were granted some levels of internal self-governing. Full independence came July 10, 1973.
Since that day the Bahamas have moved forward into prosperity. Today tourism is the major industry, and these stunning islands of gregarious people, beautiful scenery and sunny skies are one of the most popular cruise ship and vacation destinations on the planet. Bahamas which celebrates its national day on July 10th, has a population of 316,182 and gained its independence 1973.
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Posted: August 30, 2016 at 11:08 pm
The Oceania ecozone is one of the World Wildlife Fund-WWF ecozones, and is unique in not including any continental land mass. It is the smallest in land area of the WWF ecozones.
This ecozone includes the islands of the Pacific Ocean in: Micronesia, the Fijian Islands, the Hawaiian islands, and Polynesia (with the exception of New Zealand).
New Zealand, Australia, and most of Melanesia including New Guinea, Vanuatu, the Solomon Islands, and New Caledonia are included within the Australasia ecozone.
Oceania is geologically the youngest ecozone. While other ecozones include old continental land masses or fragments of continents, Oceania is composed mostly of volcanic high islands and coral atolls that arose from the sea in geologically recent times, many of them in the Pleistocene. They were created either by hotspot volcanism, or as island arcs pushed upward by the collision and subduction of tectonic plates. The islands range from tiny islets, sea stacks and coral atolls to large mountainous islands, like Hawaii and Fiji.
The climate of Oceania’s islands is tropical or subtropical, and range from humid to seasonally dry. Wetter parts of the islands are covered by Tropical and subtropical moist broadleaf forests, while the drier parts of the islands, including the leeward sides of the islands and many of the low coral islands, are covered by Tropical and subtropical dry broadleaf forests and Tropical and subtropical grasslands, savannas, and shrublands. Hawaii’s high volcanoes, Mauna Kea and Mauna Loa, are home to some rare tropical Montane grasslands and shrublands.
Since the islands of Oceania were never connected by land to a continent, the flora and fauna of the islands originally reached them from across the ocean (though at the height of the last ice age sea levels were much lower than today and many current seamounts were islands, so some now isolated islands were once less isolated). Once they reached the islands, the ancestors of Oceania’s present flora and fauna adapted to life on the islands.
Larger islands with diverse ecological niches encouraged floral and faunal adaptive radiation, whereby multiple species evolved from a common ancestor, each species adapted to a different ecological niche; the various species of Hawaiian honeycreepers (Family Drepanididae) are a classic example. Other adaptations to island ecologies include gigantism, dwarfism, and among birds, loss of flight. Oceania has a number of endemic species; Hawaii in particular is considered a global ‘center of endemism’, with its forest ecoregions having one of the highest percentages of endemic plants in the world.
Land plants disperse by several different means. Many plants, mostly ferns and mosses but also some flowering plants, disperse on the wind, relying on tiny spores or feathery seeds that can remain airborne over long distances notably Metrosideros trees from New Zealand spread on the wind across Oceania. Other plants, notably coconut palms and mangroves, produce seeds that can float in salt water over long distances, eventually washing up on distant beaches, and thus Cocos trees are ubiquitous across Oceania. Birds are also an important means of dispersal; some plants produce sticky seeds that are carried on the feet or feathers of birds, and many plants produce fruits with seeds that can pass through the digestive tracts of birds. Pandanus trees are fairly ubiquitous across Oceania.
Botanists generally agree that much of the flora of Oceania is derived from the Malesian Flora of the Malay Peninsula, Indonesia, the Philippines, and New Guinea, with some plants from Australasia and a few from the Americas, particularly in Hawaii. Easter Island has some plants from South America such as the totora reed.
Dispersal across the ocean is difficult for most land animals, and Oceania has relatively few indigenous land animals compared to other ecozones. Certain types of animals that are ecologically important on the continental ecozones, like large land predators and grazing mammals, were entirely absent from the islands of Oceania until humans brought them. Birds are relatively common, including many seabirds and some species of land birds whose ancestors may have been blown out to sea by storms. Some birds evolved into flightless species after their ancestors arrived, including several species of rails. A number of islands have indigenous lizards, including geckoes and skinks, whose ancestors probably arrived on floating rafts of vegetation washed out to sea by storms. With the exception of bats, which live on most of the island groups, there are few if any indigenous mammal species in Oceania.
Many animal and plant species have been introduced by humans in two main waves.
Malayo-Polynesian settlers brought pigs, dogs, chickens and polynesian rats to many islands; and had spread across the whole of Oceania by 1200 CE. From the seventeenth century onwards European settlers brought other animals, including cats, cattle, horses, small Asian mongoose (Herpestes javanicus), sheep, goats, and the brown rat (Rattus norvegicus). These and other introduced species, in addition to overhunting and deforestation, have dramatically altered the ecology of many of Oceania’s islands, pushing many species to extinction or near-extinction, or confining them to small islets uninhabited by humans.
The absence of predator species caused many bird species to become ‘naive’, losing the instinct to flee from predators, and to lay their eggs on the ground, which makes them vulnerable to introduced predators like cats, dogs, mongooses, and rats. The arrival of humans on these island groups often resulted in disruption of the indigenous ecosystems and waves of species extinctions (see Holocene extinction event). Easter Island, the easternmost island in Polynesia, shows evidence of a human-caused ecosystem collapse several hundred years ago, which contributed (along with slave raiding and European diseases) to a 99% decline in the human population of the island. The island, once lushly forested, is now mostly windswept grasslands. More recently, Guam’s native bird and lizard species were decimated by the introduction of the brown tree snake (Boiga irregularis) in the 1940s.
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Posted: August 29, 2016 at 7:34 am
I was going through some of my school notes today and i came across the following lecture notes id taken from a class on religion and illusions when i was still a student. Hence, I figured I introduce you guys to this very interesting topic as most of what we are tought regarding religion in the mainstream media is usually all but the same. Hope you enjoy it and find it interesting. Dont hesitate to leave your opinion at the end.
Nihilism as a philosophy seemed pass by the 1980s. Few talked about it in literature expect to declare it a dead issue. Literally, in the materialist sense, nihilism refers to a truism: from nothing, nothing comes. However, from a philosophical viewpoint, moral nihilism took on a similar connotation. One literally believed in nothing, which is somewhat of an oxymoron since to believe in nothing is to believe in something. A corner was turned in the history of nihilism once 9/11 became a reality. After this major event, religious and social science scholars began to ask whether violence could be attributed tonihilistic thinkingin other words, whether we had lost our way morally by believing in nothing, by rejecting traditional moral foundations. It was feared that an anything goes mentality and a lack of absolute moral foundations could lead to further acts of violence, as the goals forwarded by life-affirmation were being thwarted by the destructive ends of so-called violent nihilists. This position is, however, argumentative.
Extreme beliefs in values such as nationalism, patriotism, statism, secularism, or religion can also lead to violence, as one becomes unsettled by beliefs contrary to the reigning orthodoxy and strikes out violently to protect communal values. Therefore, believing in something can also lead to violence and suffering. To put the argument to rest, its not about whether one believes in something or nothing but howabsolutistthe position is; its the rigidity of values that causes pain and suffering, what Nobel prize winner Amartya Sen calls the illusion of singularity.Since 9/11, nihilism has become a favourite target to criticize and marginalize, yet its history and complexity actually lead to a more nuanced argument. Perhaps we should be looking at ways nihilism complements Western belief systemseven Christian doctrinerather than fear its implementation in ethical and moral discussions.
Brief History of Nihilism To understand why some forms of nihilism are still problematic, it is important to ask how it was used historically and for what motive. Nihilism was first thought synonymous with having no authentic values, no real ends, that ones whole existence is pure nothingness.In its earliest European roots, nihilism was initially used to label groups or ideas asinferior, especially if they were deemed threatening to establishedcommunal ideals. Nihilism as alabelwas its first function.
Nihilism initially functioned as apejorative labeland a term of abuse against modern trends that threatened to destroy either Christian hegemonic principles or tradition in general.During the seventeenth and eighteenth centuries, modernization in France meant that power shifted from the traditional feudal nobility to a central government filled with well-trained bourgeois professionals. Fearing a loss of influence, the nobility made a claim: If power shifted to responsible government, the nobility claimed that such centralization would lead to death and destructionin other words, anarchy and nothingness. Those upsetting the status quo were deemed nihilistic, a derogatory label requiring no serious burden of proof.Such labelling, however, worked both ways. The old world or tradition was deemed valueless by advocates of modernization and change who viewed the status quo as valueless; whereas, traditionalists pictured a new world, or new life form, as destructive and meaningless in its pursuit of a flawed transformation. Potential changes in power or ideology created a climate of fear, so the importance of defining ones opponent as nihilisticas nothing of valuewas as politically astute as it was reactionary. Those embracing the function of nihilism as a label are attempting to avoid scrutiny of their own values while the values of the opposition are literally annihilated.
Since those advocating communal values may feel threatened by new ideologies, it becomes imperative for the dominant power to present its political, metaphysical, or religious beliefs as eternal, universal, and objective. Typically, traditionalists have a stake in their own normative positions. This is because [t]he absoluteness of [ones] form of life makes [one]feel safe and at home. This means that [perfectionists]have a great interest in the maintenance of their form of life and its absoluteness.The existence of alternative beliefs and values, as well as a demand for intersubjective dialogue, is both a challenge and a threat to the traditionalist because [i]t shows people that their own form of life is not as absolute as they thought it was, and this makes them feel uncertain. . . . However, if one labels the Other as nihilistic without ever entering into a dialogue, one may become myopic, dismissing the relative value of other life forms one chooses not to see. This means that one cant see what they [other cultural groups]are doing, and why they are doing it, why they may be successful . . . Therefore, one misses the dynamics of cultural change.
Through the effect of labelling, the religious-oriented could claim that nihilists, and thus atheists by affiliation, would not feel bound by moral norms, and as a result would lose the sense that life has meaning and therefore tend toward despair and suicide.death of God. Christians argued that if there is no divine lawmaker, moral law would become interpretative, contested, and situational. The end result: [E]ach man will tend to become a law unto himself. If God does not exist to choose for the individual, the individual will assume the former prerogative of God and choose for himself. It was this kind of thinking that led perfectionists to assume that any challenge to the Absolute automatically meant moral indifference, moral relativism, and moral chaos. Put simply,nihilists were the enemy.
Nihilists were accused of rejecting ultimate values, embracing instead an all values are equal mentalitybasically, anything goes. And like Islam today, nihilists would become easy scapegoats.
Late 19th 20th Century;Nietzsche and the Death of God
Friedrich Nietzsche is still the most prestigious theorist of nihilism. Influenced by Christianitys dominant orthodoxy in the nineteenth century, Nietzsche believed that the Christian religion was nihilism incarnate. Since Christian theology involved a metaphysical reversal of temporal reality and a belief in God that came from nothing, the Christian God became the deification of nothingness, the will to nothingness pronounced holy. Nietzsche claimed that Christian metaphysics became an impediment to life-affirmation. Nietzsche explains: If one shifts the centre of gravity of life out of life into the Beyondinto nothingnessone has deprived life of its centre of gravity . . . So to live that there is no longer any meaning in living:that now becomes the meaning of life.What Nietzsche rejected more was the belief that one could create a totalizing system to explain all truths. In other words, he repudiated any religion or dogma that attempted to show how the entire body of knowledge [could]be derived from a small set of fundamental, self-evident propositions(i.e., stewardship). Nietzsche felt that we do not have the slightest right to posit a beyond or an it-self of things that is divine or the embodiment of morality.
Without God as a foundation for absolute values, all absolute values are deemed suspect (hence the birth of postmodernism). For Nietzsche, this literally meant that the belief in the Christian god ha[d]become unworthy of belief.This transition from the highest values to the death of God was not going to be a quick one; in fact, the comfort provided by an absolute divinity could potentially sustain its existence for millennia. Nietzsche elaborates: God is dead; but given the way of men, there may still be caves for thousands of years in which his shadow will be shown.And wewe still have to vanquish his shadow too.
We are left then with a dilemma: Either we abandon our reverences for the highest values and subsist, or we maintain our dependency on absolutes at the cost of our own non-absolutist reality. For Nietzsche, the second option was pure nothingness: So we can abolish either our reverences or ourselves. The latter constitutes nihilism. All one is left with are contested, situational value judgements, and these are resolved in the human arena.
One can still embrace pessimism, believing that without some form of an absolute, our existence in this world will take a turn for the worse. To avoid the trappings of pessimism and passivity, Nietzsche sought a solution to such nihilistic despair through the re-evaluation of the dominant, life-negating values. This makes Nietzsche an perspectivism a philosophy of resolution in the form of life-affirmation. It moves past despair toward a transformative stage in which new values are posited to replace the old table of values. As Reginster acknowledges, one should regard the affirmation of life as Nietzsches defining philosophical achievement. What this implies is a substantive demand to live according to a constant re-evaluation of values. By taking full responsibility for this task, humankind engages in the eternal recurrence, a recurrence of life-affirming values based on acceptance of becoming and the impermanence of values. Value formation is both fluid and cyclical.
Late-20th Century 21st Century;The Pessimism of the Post-9/11 Era
Since the events of September 11, 2001, nihilism has returned with a vengeance to scholarly literature; however, it is being discussed in almost exclusively negative terms. The labelling origin of nihilism has taken on new life in a context of suicide bombings, Islamophobia, and neoconservative rhetoric. For instance, Canadian Liberal leader Michael Ignatieff described different shades of negative nihilismtragic, cynical, and fanaticalin his bookThe Lesser Evil.Tragic nihilism begins from a foundation of noble, political intentions, but eventually this ethic of restraint spirals toward violence as the only end(i.e., Vietnam). Two sides of an armed struggle may begin with high ideals and place limitations on their means to achieve viable political goals, but such noble ends eventually become lost in all the carnage. Agents of a democratic state may find themselves driven by the horror of terror to torture, to assassinate, to kill innocent civilians, all in the name of rights and democracy. As Ignateiff states, they slip from the lesser evil [legitimate use of force]to the greater [violence as an end in itself].
However,cynical nihilism is even more narcissistic. In this case, violence does not begin as a means to noble goals. Instead, [i]t is used, from the beginning, in the service of cynical or self-serving [ends]. The term denotes narcissistic prejudice because it justifies the commission of violence for the sake of personal aggrandizement, immortality, fame, or power rather than as a means to a genuinely political end, like revolution [for social justice]or the liberation of a people.Cynical nihilists were never threatened in any legitimate way. Their own vanity, ego, greed, or need to control others drove them to commit violence against innocent civilians (e.g., Saddam Hussein in Kuwait or Bush in Iraq).
Finally,fanatical nihilism does not suffer from a belief in nothing. In actuality, this type of nihilism is dangerous because one believes in too much. What fanatical nihilism does involve is a form of conviction so intense, a devotion so blind, that it becomes impossible to see that violence necessarily betrays the ends that conviction seeks to achieve. The fanatical use of ideology to justify atrocity negates any consideration of the human cost of such fundamentalism. As a result, nihilism becomes willed indifference to the human agents sacrificed on the alter of principle. . . . Here nihilism is not a belief in nothing at all; it is, rather, the belief that nothing about particular groups of human beings matters enough to require minimizing harm to them.Fanatical nihilism is also important to understand because many of the justifications are religious. States Ignatieff:
From a human rights standpoint, the claim that such inhumanity can be divinely inspired is a piece of nihilism, an inhuman devaluation of the respect owed to all persons, and moreover a piece of hubris, since, by definition, human beings have no access to divine intentions, whatever they may be.
Positive Nihilism In the twenty-first century, humankind is searching for a philosophy to counter destructive, non-pragmatic forms of nihilism. As a middle path,positive nihilism accentuates life-affirmation through a widening of dialogue. Positively stated: [The Philosopher] . . ., having rejected the currently dominant values, must raise other values, by virtue of which life and the universe cannot only be justified but also become endearing and valuable. Rejecting any unworkable table of values, humankind now erects another table with a new ranking of values and new ideals of humanity, society, and state.Positive nihilismin both its rejection of absolute truths and its acceptance of contextual truthsis life-affirming since small-t truths are the best mere mortals can hope to accomplish. Human beings can reach for higher truths; they just do not have the totalizing knowledge required for Absolute Truth. In other words, we are not God, but we are still attempting to be God on a good day. We still need valuesin other words, we are not moral nihilists or absolutistsbut we realize that the human condition is malleable. Values come and go, and we have to be ready to bend them in the right direction in the moment moral courage requires it.
Nihilism does not have to be a dangerous or negative philosophy; it can be a philosophy of freedom. Basically, the entire purpose of positive nihilism is to transform values that no longer work and replace them with values that do. By aiding in a process that finds meaningful values through negotiation,positive nihilism prevents the exclusionary effect of perfectionism, the deceit of nihilistic labelling, as well as the senseless violence of fanatical nihilism. It is at this point that nihilism can enter its life-affirming stage and become a compliment to pluralism, multiculturalism, and the roots of religion, those being love, charity, and compassion.
Source; Professor Stuart Chambers.
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Posted: August 27, 2016 at 7:22 pm
Alternate Title: Republic of Seychelles
National anthem of Seychelles
Seychelles, island republic in the western Indian Ocean, comprising about 115 islands. The islands are home to lush tropical vegetation, beautiful beaches, and a wide variety of marine life. Situated between latitudes 4 and 11 S and longitudes 46 and 56 E, the major islands of Seychelles are located about 1,000 miles (1,600 km) east of Kenya and about 700 miles (1,100 km) northeast of Madagascar. The capital, Victoria, is situated on the island of Mah.
Seychelles, one of the worlds smallest countries, is composed of two main island groups: the Mah group of more than 40 central, mountainous granitic islands and a second group of more than 70 outer, flat, coralline islands. The islands of the Mah group are rocky and typically have a narrow coastal strip and a central range of hills. The overall aspect of those islands, with their lush tropical vegetation, is that of high hanging gardens overlooking silver-white beaches and clear lagoons. The highest point in Seychelles, Morne Seychellois (2,969 feet [905 metres]), situated on Mah, is located within this mountainous island group. The coralline islands, rising only a few feet above sea level, are flat with elevated coral reefs at different stages of formation. These islands are largely waterless, and very few have a resident population.
The climate is tropical oceanic, with little temperature variation during the year. Daily temperatures rise to the mid-80s F (low 30s C) in the afternoon and fall to the low 70s F (low 20s C) at night. Precipitation levels vary greatly from island to island; on Mah, annual precipitation ranges from 90 inches (2,300 mm) at sea level to 140 inches (3,560 mm) on the mountain slopes. Humidity is persistently high but is ameliorated somewhat in locations windward of the prevailing southeast trade winds.
Of the roughly 200 plant species found in Seychelles, some 80 are unique to the islands, including screw pines (see pandanus), several varieties of jellyfish trees, latanier palms, the bois rouge, the bois de fer, Wrights gardenia, and the most famous, the coco de mer. The coco de merwhich is found on only two islandsproduces a fruit that is one of the largest and heaviest known and is valued by a number of Asian cultures for believed aphrodisiac, medicinal, mystic, and other properties. The Seychellois government closely monitors the quantity and status of the trees, and, although commerce is regulated to prevent overharvesting, poaching is a concern.
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Wildlife includes a remarkably diverse array of marine life, including more than 900 identified species of fish; green sea turtles and giant tortoises also inhabit the islands. Endemic species include birds such as Seychelles bulbuls and cave-dwelling Seychelles swiftlets; several species of local tree frogs, snails, and wormlike caecilians; Seychelles wolf snakes and house snakes; tiger chameleons; and others. Endemic mammals are few; both fruit bats (Pteropus seychellensis) and Seychelles sheath-tailed bats (Coleura seychellensis) are endemic to the islands. Indian mynahs, barn owls, and tenrecs (small shrewlike or hedgehoglike mammals introduced from Madagascar) are also found.
Considerable efforts have been made to preserve the islands marked biodiversity. Seychelles government has established several nature preserves and marine parks, including the Aldabra Islands and Valle de Mai National Park, both UNESCO World Heritage sites. The Aldabra Islands, a large atoll, are the site of a preserve inhabited by tens of thousands of giant tortoises, the worlds oldest living creatures, which government conservation efforts have helped rescue from the brink of extinction. Valle de Mai National Park is the only place where all six of the palm species endemic to Seychelles, including the coco de mer, may be found together. Cousin Island is home to a sanctuary for land birds, many endemic to the islands, including the Seychelles sunbird (a type of hummingbird) and the Seychelles brush warbler. The nearby Cousine Island is part private resort and part nature preserve, noted for its sea turtles, giant tortoises, and assorted land birds. Bird Island is the breeding ground for millions of terns, turtle doves, shearwaters, frigate birds, and other seabirds that flock there each year.
The original French colonists on the previously uninhabited islands, along with their black slaves, were joined in the 19th century by deportees from France. Asians from China, India, and Malaya (Peninsular Malaysia) arrived later in smaller numbers. Widespread intermarriage has resulted in a population of mixed descent.
Creole, also called Seselwa, is the mother tongue of most Seychellois. Under the constitution, Creole, English, and French are recognized as national languages.
More than four-fifths of the population are Roman Catholics. There are also Anglicans, Christians of other denominations, Hindus, and Muslims.
More than four-fifths of the population live on Mah, many of them in the capital city, Victoria. The birth and death rates, as well as the annual population growth rate, are below the global average. Some one-fourth of the population are younger than age 15, and about one-half are under age 30. Life expectancy for both men and women is significantly higher than the global average.
Seychelles has a mixed, developing economy that is heavily dependent upon the service sector in general and the tourism industry in particular. Despite continued visible trade deficits, the economy has experienced steady growth. The gross domestic product (GDP) is growing more rapidly than the population. The gross national income (GNI) per capita is significantly higher than those found in most nearby continental African countries.
Agriculture accounts for only a fraction of the GDP and employs an equally modest proportion of the workforce. Arable land is limited and the soil is generally poorand the country remains dependent upon imported foodstuffsbut copra (from coconuts), cinnamon bark, vanilla, tea, limes, and essential oils are exported. Seychelles has a modern fishing industry that supplies both domestic and foreign markets; canned tuna is a particularly important product. The extraction of guano for export is also an established economic activity.
The countrys growing manufacturing sectorwhich has expanded to account for almost one-sixth of the total GDPis composed largely of food-processing plants; production of alcoholic beverages and of soft drinks is particularly significant. Animal feed, paint, and other goods are also produced.
Seychelles sizable trade deficit is offset by income from the tourism industry and from aid and investment. Although the countrys relative prosperity has not made it a preferred aid recipient, it does receive assistance from the World Bank, the European Union, the African Development Bank, and a variety of contributing countries, and aid obtained per capita is relatively high. The Central Bank of Seychelles, located in Victoria, issues the official currency, the Seychelles rupee.
Seychelles main imports are petroleum products, machinery, and foodstuffs. Canned tuna, copra, frozen fish, and cinnamon are the most important exports, together with the reexport of petroleum products. Significant trade partners include France, the United Kingdom, Saudi Arabia, and Germany.
The service sector accounts for nearly four-fifths of the GDP and employs the largest proportion of the workforce, almost three-fourths of all labourers. After the opening of an international airport on Mah in 1971, the tourism industry grew rapidly, and at the beginning of the 21st century it provided almost one-fourth of the total GDP. Each year Seychelles draws thousands of tourists, many attracted by the islands magnificent venues for scuba diving, surfing, windsurfing, fishing, swimming, and sunbathing. The warm southeasterly trade winds offer ideal conditions for sailing, and the waters around Mah and the other islands are afloat with small boats.
The majority of Seychelles roadways are paved, most of which are on the islands of Mah and Praslin; there are no railroads. Ferry services operate between the islandsfor example, linking Victoria with destinations that include Praslin and La Digue. Air service is centred on Seychelles International Airport, located near Victoria on Mah, and the smaller airports and airstrips found on several islands. Seychelles has air connections with a number of foreign cities and direct flights to major centres that include London, Paris, Frankfurt, Rome, and Bangkok. Scheduled domestic flights, provided by Air Seychelles, chiefly offer service between Mah and Praslin, although chartered flights elsewhere are also available. The tsunami that reached Seychelles in 2004 damaged portions of the transportation infrastructure, including the road linking Victoria with the international airport.
Telecommunications infrastructure in Seychelles is quite developed. The country has a high rate of cellular telephone useamong the highest in sub-Saharan Africaand, at the beginning of the 21st century, the use of personal computers in Seychelles was several times the average for the region.
Under the 1993 constitution, Seychelles is a republic. The head of state and government is the president, who is directly elected by popular vote and may hold office for up to three consecutive five-year terms. Members of the National Assembly serve five-year terms. A majority of the available National Assembly seats are filled by direct election; a smaller portion are distributed on a proportional basis to those parties that win a minimum of one-tenth of the vote. The president appoints a Council of Ministers, which acts as an advisory body. The country is divided into more than 20 administrative divisions.
The Seychellois judiciary includes a Court of Appeal, a Supreme Court, and Magistrates Courts; the Constitutional Court is a branch of the Supreme Court.
Suffrage is universal; Seychellois are eligible to vote at age 17. Women participate actively in the government of the country and have held numerous posts, including positions in the cabinet and a proportion of seats in the National Assembly.
The Peoples Party (formerly the Seychelles Peoples Progressive Front) was the sole legal party from 1978 until 1991. It is still the countrys primary political party, but other parties are also active in Seychellois politics, including the New Democratic Party (formerly the Seychelles Democratic Party), the Seychelles National Party, and the Seychelles Movement for Democracy.
Seychelles defense forces are made up of an army, a coast guard (including naval and airborne wings), and a national guard. There is no conscription; military service is voluntary, and individuals are generally eligible at age 18 (although younger individuals may serve with parental consent).
In general, homes play a highly visible part in maintaining traditional Seychellois life. Many old colonial houses are well preserved, although corrugated iron roofs have generally replaced the indigenous palm thatch. Groups tend to gather on the verandahs of their houses, which are generally recognized as social centres.
The basis of the school system is a free, compulsory, 10-year public school education. Education standards have risen steadily, and nearly all children of primary-school age attend school. The countrys first university, the University of Seychelles, began accepting students in 2009. The literacy rate in Seychelles is significantly higher than the regional and global averages for both men and women.
Seychellois culture has been shaped by a combination of European, African, and Asian influences. The main European influence is French, recognizable in Seselwa, the Creole language that is the lingua franca of the islands, and in Seychellois food and religion; the French introduced Roman Catholicism, the religion of the majority of the islanders. African influence is revealed in local music and dance as well as in Seselwa. Asian elements are evident in the islands cuisine but are particularly dominant in business and trade.
Holidays observed in Seychelles include Liberation Day, which commemorates the anniversary of the 1977 coup, on June 5; National Day, June 18; Independence Day, June 29; the Feast of the Assumption, August 15; All Saints Day, November 1; the Feast of the Immaculate Conception, December 8; and Christmas, December 25.
Because of the exorbitant expense of the large and lavish wedding receptions that are part of Seychellois tradition, many couples never marry; instead, they may choose to live en mnage, achieving a de facto union by cohabitating without marriage. There is little or no social stigma related to living en mnage, and the arrangement is recognized by the couples family and friends. The instance of couples living en mnage increases particularly among lower income groups.
Dance plays an important role in Seychellois society. Both the sga and the moutya, two of the most famous dances performed in Seychelles, mirror traditional African customs. The sensual dances blend religion and social relations, two elements central to African life. The complicated and compelling dance movements were traditionally carried out under moonlight to the beat of African drums. Dances were once regular events in village halls, but these have largely died out in recent years; now dances take place in modern nightclubs.
Seychellois enjoy participating in and watching several team sports. The national stadium, located in Victoria, offers a year-round program of events. Mens and womens volleyball are popular, and several Seychellois players and referees participate at the international level. Football (soccer) is also a favourite, and Seychellois teams frequently travel to East Africa and India to play in exhibition matches and tournaments. The Seychelles national Olympic committee was established in 1979 and was recognized that year by the International Olympic Committee. The country made its official Olympic debut at the 1980 Moscow Games, but its first Olympic athlete was Henri Dauban de Silhouette, who competed for Great Britain in the javelin throw at the 1924 Paris Games.
Much of the countrys radio, television, and print media is under government control. There are several independent publications, including Seychelles Weekly and Vizyon.
The islands were known by traders from the Persian Gulf centuries ago, but the first recorded landing on the uninhabited Seychelles was made in 1609 by an expedition of the British East India Company. The archipelago was explored by the Frenchman Lazare Picault in 1742 and 1744 and was formally annexed to France in 1756. The archipelago was named Schelles, later changed by the British to Seychelles. War between France and Britain led to the surrender of the archipelago to the British in 1810, and it was formally ceded to Great Britain by the Treaty of Paris in 1814. The abolition of slavery in the 1830s deprived the islands European colonists of their labour force and compelled them to switch from raising cotton and grains to cultivating less-labour-intensive crops such as coconut, vanilla, and cinnamon. In 1903 Seychellesuntil that time administered as a dependency of Mauritiusbecame a separate British crown colony. A Legislative Council with elected members was introduced in 1948.
In 1963 the United States leased an area on the main island, Mah, and built an air force satellite tracking station there; this brought regular air travel to Seychelles for the first time, in the form of a weekly seaplane shuttle that operated from Mombasa, Kenya.
In 1970 Seychelles obtained a new constitution, universal adult suffrage, and a governing council with an elected majority. Self-government was granted in 1975 and independence in 1976, within the Commonwealth of Nations. In 1975 a coalition government was formed with James R. Mancham as president and France-Albert Ren as prime minister. In 1977, while Mancham was abroad, Ren became president in a coup dtat led by the Seychelles Peoples United Party (later restyled the Seychelles Peoples Progressive Front [SPPF], from 2009 the Peoples Party [Parti Lepep]).
In 1979 a new constitution transformed Seychelles into a one-party socialist state, with Rens SPPF designated the only legal party. This change was not popular with many Seychellois, and during the 1980s there were several coup attempts. Faced with mounting pressure from the countrys primary sources of foreign aid, Rens administration began moving toward more democratic rule in the early 1990s, with the return of multiparty politics and the promulgation of a new constitution. The country also gradually abandoned its socialist economy and began to follow market-based economic strategies by privatizing most parastatal companies, encouraging foreign investment, and focusing efforts on marketing Seychelles as an offshore business and financial hub. As Seychelles entered the 21st century, the SPPF continued to dominate the political scene. After the return of multiparty elections, Ren was reelected three times before eventually resigning in April 2004 to allow Vice Pres. James Michel to succeed him as president.
In late 2004 some of the islands were hit by a tsunami, which severely damaged the environment and the countrys economy. The economy was an important topic in the campaigning leading up to the presidential election of 2006, in which Michel emerged with a narrow victory to win his first elected term. He was reelected in 2011. One of Michels ongoing concerns was piracy in the Indian Ocean, which had surged since 2009 and threatened the countrys fishing and tourism industries. To that end, the Seychellois government worked with several other countries and international organizations to curb the illegal activity.
In October 2015 Michel called for an early presidential election, rather than wait until it was due in 2016. Michel was standing for his third term, again representing the Peoples Party. The election was held December 35, 2015. For the first time since the return of multiparty politics in 1993, the Peoples Partys candidate did not win outright in the first round of voting. Michel garnered 47.76 percent of the vote; his nearest challenger was Wavel Ramkalawan of the Seychelles National Party (SNP), who took 33.93 percent. Ramkalawan was an Anglican priest who was the leader of the SNP and had run for president in previous elections. The runoff election was held December 1618. On December 19 Michel was declared the winner by a very narrow margin, taking 50.15 percent of the vote, with only 193 votes between him and Ramkalawan. Michel was quickly sworn in the next day for his third term. Ramkalawan voiced allegations of voting irregularities and asked for a recount.
Posted: August 21, 2016 at 11:12 am
Alternative medicine may be defined as non-standard, unconventional treatments for glaucoma.
Use of alternative medicine continues to increase, although it must be noted that some of these treatment alternatives have no proven clinical effect.
Regular exercise and relaxation techniques can be beneficial for lowering eye pressure and may have a positive impact on your overall health and other glaucoma risk factors including high blood pressure.
Always talk to your doctor before starting any alternative therapies.
Proponents of homeopathic medicine believe that symptoms represent the bodys attack against disease, and that substances which induce the symptoms of a particular disease or diseases can help the body ward off illness.
The Food and Drug Administration (FDA) has not tested homeopathic remedies for safety or effectiveness. There is no guarantee that they contain consistent ingredients, or that dosage recommendations are accurate. It would be a mistake to use homeopathic remedies and dismiss valid therapies, delaying proven treatment for serious conditions.
Holistic medicine is a system of health care designed to assist individuals in harmonizing mind, body, and spirit. Some of the more popular therapies include good nutrition, physical exercise, and self-regulation techniques including meditation, biofeedback and relaxation training. While holistic treatments can be part of a good physical regimen, there is no proof of their usefulness in glaucoma therapy.
No conclusive studies prove a connection between specific foods and glaucoma, but it is reasonable to assume that what you eat and drink and your general health have an effect on the disease.
Some studies have shown that significant caffeine intake over a short time can slightly elevate intraocular eye pressure (IOP) for one to three hours. However, other studies indicate that caffeine has no meaningful impact on IOP. To be safe, people with glaucoma are advised to limit their caffeine intake to moderate levels.
Studies have also shown that as many as 80% of people with glaucoma who consume an entire quart of water over the course of twenty minutes experience elevated IOP, as compared to only 20% of people who dont have glaucoma. Since many commercial diet programs stress the importance of drinking at least eight glasses of water each day, to be safe, people with glaucoma are encouraged to consume water in small amounts throughout the day.
The ideal way to ensure a proper supply of essential vitamins and minerals is by eating a balanced diet. If you are concerned about your own diet, you may want to consult with your doctor about taking a mulitvitamin or multimineral nutritional supplement.
Some of the vitamins and minerals important to the eye include zinc and copper, antioxidant vitamins C, E, and A (as beta carotene), and selenium, an antioxidant mineral.
An extract of the European blueberry, bilberry is available through the mail and in some health food stores. It is most often advertised as an antioxidant eye health supplement that advocates claim can protect and strengthen the capillary walls of the eyes, and thus is especially effective in protecting against glaucoma, cataracts, and macular degeneration. There is some data indicating that bilberry may improve night vision and recovery time from glare, but there is no evidence that it is effective in the treatment or prevention of glaucoma.
There is some evidence suggesting that regular exercise can reduce eye pressure on its own, and can also have a positive impact on other glaucoma risk factors including diabetes and high blood pressure.
In a recent study, people with glaucoma who exercised regularly for three months reduced their IOPs an average of 20%. These people rode stationary bikes 4 times per week for 40 minutes. Measurable improvements in eye pressure and physical conditioning were seen at the end of three months. These beneficial effects were maintained by continuing to exercise at least three times per week; lowered IOP was lost if exercise was stopped for more than two weeks.
In an ongoing study, glaucoma patients who walked briskly 4 times per week for 40 minutes were able to lower their IOP enough to eliminate the need for beta blockers. Final results are not available, but there is hope that glaucoma patients with extremely high IOP who maintain an exercise schedule and continue beta-blocker therapy could significantly reduce their IOP.
Regular exercise may be a useful addition to the prevention of visual loss from glaucoma, but only your eye doctor can assess the effects of exercise on your eye pressure. Some forms of glaucoma (such as closed-angle) are not responsive to the effects of exercise, and other forms of glaucoma (for example, pigmentary glaucoma) may actually develop a temporary increase in IOP after vigorous exercise. And remember — exercise cannot replace medications or doctor visits!
The long-term effects of repeatedly assuming a head-down or inverted position on the optic nerve head (the nerve that carries visual images to the brain) have not been adequately demonstrated, but due to the potential for increased IOP, people with glaucoma should be careful about these kinds of exercises.
Glaucoma patients should let their doctors know if yoga shoulder and headstands or any other recreational body inversion exercises that result in head-down or inverted postures over extended periods of time are part of their exercise routines.
The results of studies regarding changes in IOP following relaxation and biofeedback sessions have generated some optimism in controlling selected cases of open-angle glaucoma, but further research is needed.
However, findings that reduced blood pressure and heart rate can be achieved with relaxation and biofeedback techniques show promise that non-medicinal and non-surgical techniques may be effective methods of treating and controlling open-angle glaucoma.
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