Geography: The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)Geography, Medical: The area of medicine concerned with the effects on health and disease due to geographic factors such as CLIMATE, environmental conditions, and geographic location.Topography, Medical: The systematic surveying, mapping, charting, and description of specific geographical sites, with reference to the physical features that were presumed to influence health and disease. Medical topography should be differentiated from EPIDEMIOLOGY in that the former emphasizes geography whereas the latter emphasizes disease outbreaks.Folklore: The common orally transmitted traditions, myths, festivals, songs, superstitions, and stories of all peoples.Genetics, Population: The discipline studying genetic composition of populations and effects of factors such as GENETIC SELECTION, population size, MUTATION, migration, and GENETIC DRIFT on the frequencies of various GENOTYPES and PHENOTYPES using a variety of GENETIC TECHNIQUES.Phylogeography: A field of study concerned with the principles and processes governing the geographic distributions of genealogical lineages, especially those within and among closely related species. (Avise, J.C., Phylogeography: The History and Formation of Species. Harvard University Press, 2000)Linguistics: The science of language, including phonetics, phonology, morphology, syntax, semantics, pragmatics, and historical linguistics. (Random House Unabridged Dictionary, 2d ed)South AmericaGeographic Information Systems: Computer systems capable of assembling, storing, manipulating, and displaying geographically referenced information, i.e. data identified according to their locations.Residence Characteristics: Elements of residence that characterize a population. They are applicable in determining need for and utilization of health services.Secondary Care Centers: A healthcare facility equipped to provide all but the most specialized forms of care, surgery, and diagnostic techniques.Genetic Variation: Genotypic differences observed among individuals in a population.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Demography: Statistical interpretation and description of a population with reference to distribution, composition, or structure.City Planning: Comprehensive planning for the physical development of the city.Emigration and Immigration: The process of leaving one's country to establish residence in a foreign country.Climate: The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Sympatry: In evolutionary theory, overlapping geographic distribution of diverging species. In sympatric GENETIC SPECIATION, genetic diversion occurs without geographic separation.Genetic Speciation: The splitting of an ancestral species into daughter species that coexist in time (King, Dictionary of Genetics, 6th ed). Causal factors may include geographic isolation, HABITAT geometry, migration, REPRODUCTIVE ISOLATION, random GENETIC DRIFT and MUTATION.Suburban Population: The inhabitants of peripheral or adjacent areas of a city or town.Spatial Analysis: Techniques which study entities using their topological, geometric, or geographic properties.Ecology: The branch of science concerned with the interrelationship of organisms and their ENVIRONMENT, especially as manifested by natural cycles and rhythms, community development and structure, interactions between different kinds of organisms, geographic distributions, and population alterations. (Webster's, 3d ed)United StatesSocioeconomic Factors: Social and economic factors that characterize the individual or group within the social structure.Geology: The science of the earth and other celestial bodies and their history as recorded in the rocks. It includes the study of geologic processes of an area such as rock formations, weathering and erosion, and sedimentation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)EuropePrincipal Component Analysis: Mathematical procedure that transforms a number of possibly correlated variables into a smaller number of uncorrelated variables called principal components.Chromosomes, Human, Y: The human male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans.Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Haplotypes: The genetic constitution of individuals with respect to one member of a pair of allelic genes, or sets of genes that are closely linked and tend to be inherited together such as those of the MAJOR HISTOCOMPATIBILITY COMPLEX.Amplified Fragment Length Polymorphism Analysis: The detection of RESTRICTION FRAGMENT LENGTH POLYMORPHISMS by selective PCR amplification of restriction fragments derived from genomic DNA followed by electrophoretic analysis of the amplified restriction fragments.Biodiversity: The variety of all native living organisms and their various forms and interrelationships.Rural Health Services: Health services, public or private, in rural areas. The services include the promotion of health and the delivery of health care.BrazilHealth Services Accessibility: The degree to which individuals are inhibited or facilitated in their ability to gain entry to and to receive care and services from the health care system. Factors influencing this ability include geographic, architectural, transportational, and financial considerations, among others.Censuses: Enumerations of populations usually recording identities of all persons in every place of residence with age or date of birth, sex, occupation, national origin, language, marital status, income, relation to head of household, information on the dwelling place, education, literacy, health-related data (e.g., permanent disability), etc. The census or "numbering of the people" is mentioned several times in the Old Testament. Among the Romans, censuses were intimately connected with the enumeration of troops before and after battle and probably a military necessity. (From Last, A Dictionary of Epidemiology, 3d ed; Garrison, An Introduction to the History of Medicine, 4th ed, p66, p119)Microsatellite Repeats: A variety of simple repeat sequences that are distributed throughout the GENOME. They are characterized by a short repeat unit of 2-8 basepairs that is repeated up to 100 times. They are also known as short tandem repeats (STRs).DNA, Mitochondrial: Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.Asia: The largest of the continents. It was known to the Romans more specifically as what we know today as Asia Minor. The name comes from at least two possible sources: from the Assyrian asu (to rise) or from the Sanskrit usa (dawn), both with reference to its being the land of the rising sun, i.e., eastern as opposed to Europe, to the west. (From Webster's New Geographical Dictionary, 1988, p82 & Room, Brewer's Dictionary of Names, 1992, p34)Gene Flow: The change in gene frequency in a population due to migration of gametes or individuals (ANIMAL MIGRATION) across population barriers. In contrast, in GENETIC DRIFT the cause of gene frequency changes are not a result of population or gamete movement.Continental Population Groups: Groups of individuals whose putative ancestry is from native continental populations based on similarities in physical appearance.Urbanization: The process whereby a society changes from a rural to an urban way of life. It refers also to the gradual increase in the proportion of people living in urban areas.Healthcare Disparities: Differences in access to or availability of medical facilities and services.Ethnic Groups: A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.Urban Population: The inhabitants of a city or town, including metropolitan areas and suburban areas.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Small-Area Analysis: A method of analyzing the variation in utilization of health care in small geographic or demographic areas. It often studies, for example, the usage rates for a given service or procedure in several small areas, documenting the variation among the areas. By comparing high- and low-use areas, the analysis attempts to determine whether there is a pattern to such use and to identify variables that are associated with and contribute to the variation.Middle East: The region of southwest Asia and northeastern Africa usually considered as extending from Libya on the west to Afghanistan on the east. (From Webster's New Geographical Dictionary, 1988)British Columbia: A province of Canada on the Pacific coast. Its capital is Victoria. The name given in 1858 derives from the Columbia River which was named by the American captain Robert Gray for his ship Columbia which in turn was named for Columbus. (From Webster's New Geographical Dictionary, 1988, p178 & Room, Brewer's Dictionary of Names, 1992, p81-2)Cluster Analysis: A set of statistical methods used to group variables or observations into strongly inter-related subgroups. In epidemiology, it may be used to analyze a closely grouped series of events or cases of disease or other health-related phenomenon with well-defined distribution patterns in relation to time or place or both.AfricaRural Population: The inhabitants of rural areas or of small towns classified as rural.OregonOceans and Seas: A great expanse of continuous bodies of salt water which together cover more than 70 percent of the earth's surface. Seas may be partially or entirely enclosed by land, and are smaller than the five oceans (Atlantic, Pacific, Indian, Arctic, and Antarctic).Language: A verbal or nonverbal means of communicating ideas or feelings.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Bayes Theorem: A theorem in probability theory named for Thomas Bayes (1702-1761). In epidemiology, it is used to obtain the probability of disease in a group of people with some characteristic on the basis of the overall rate of that disease and of the likelihood of that characteristic in healthy and diseased individuals. The most familiar application is in clinical decision analysis where it is used for estimating the probability of a particular diagnosis given the appearance of some symptoms or test result.Health Status Disparities: Variation in rates of disease occurrence and disabilities between population groups defined by socioeconomic characteristics such as age, ethnicity, economic resources, or gender and populations identified geographically or similar measures.European Continental Ancestry Group: Individuals whose ancestral origins are in the continent of Europe.Commerce: The interchange of goods or commodities, especially on a large scale, between different countries or between populations within the same country. It includes trade (the buying, selling, or exchanging of commodities, whether wholesale or retail) and business (the purchase and sale of goods to make a profit). (From Random House Unabridged Dictionary, 2d ed, p411, p2005 & p283)Environment: The external elements and conditions which surround, influence, and affect the life and development of an organism or population.Catchment Area (Health): A geographic area defined and served by a health program or institution.Urban Health: The status of health in urban populations.MexicoHistory, 20th Century: Time period from 1901 through 2000 of the common era.Poisson Distribution: A distribution function used to describe the occurrence of rare events or to describe the sampling distribution of isolated counts in a continuum of time or space.North AmericaPopulation Density: Number of individuals in a population relative to space.WalesCaliforniaEnglandOntario: A province of Canada lying between the provinces of Manitoba and Quebec. Its capital is Toronto. It takes its name from Lake Ontario which is said to represent the Iroquois oniatariio, beautiful lake. (From Webster's New Geographical Dictionary, 1988, p892 & Room, Brewer's Dictionary of Names, 1992, p391)Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Mortality: All deaths reported in a given population.Sex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Conservation of Natural Resources: The protection, preservation, restoration, and rational use of all resources in the total environment.Medicare: Federal program, created by Public Law 89-97, Title XVIII-Health Insurance for the Aged, a 1965 amendment to the Social Security Act, that provides health insurance benefits to persons over the age of 65 and others eligible for Social Security benefits. It consists of two separate but coordinated programs: hospital insurance (MEDICARE PART A) and supplementary medical insurance (MEDICARE PART B). (Hospital Administration Terminology, AHA, 2d ed and A Discursive Dictionary of Health Care, US House of Representatives, 1976)Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Social Class: A stratum of people with similar position and prestige; includes social stratification. Social class is measured by criteria such as education, occupation, and income.World Health: The concept pertaining to the health status of inhabitants of the world.Poverty: A situation in which the level of living of an individual, family, or group is below the standard of the community. It is often related to a specific income level.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Rural Health: The status of health in rural populations.Gene Frequency: The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Income: Revenues or receipts accruing from business enterprise, labor, or invested capital.Population Dynamics: The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.China: A country spanning from central Asia to the Pacific Ocean.ScotlandDelivery of Health Care: The concept concerned with all aspects of providing and distributing health services to a patient population.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Genome, Human: The complete genetic complement contained in the DNA of a set of CHROMOSOMES in a HUMAN. The length of the human genome is about 3 billion base pairs.African Americans: Persons living in the United States having origins in any of the black groups of Africa.Models, Statistical: Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.Public Health: Branch of medicine concerned with the prevention and control of disease and disability, and the promotion of physical and mental health of the population on the international, national, state, or municipal level.Health Policy: Decisions, usually developed by government policymakers, for determining present and future objectives pertaining to the health care system.African Continental Ancestry Group: Individuals whose ancestral origins are in the continent of Africa.Age Distribution: The frequency of different ages or age groups in a given population. The distribution may refer to either how many or what proportion of the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.IndiaModels, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Hispanic Americans: Persons living in the United States of Mexican (MEXICAN AMERICANS), Puerto Rican, Cuban, Central or South American, or other Spanish culture or origin. The concept does not include Brazilian Americans or Portuguese Americans.Population Surveillance: Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.Sex Distribution: The number of males and females in a given population. The distribution may refer to how many men or women or what proportion of either in the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.Selection, Genetic: Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.Regression Analysis: Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.Cause of Death: Factors which produce cessation of all vital bodily functions. They can be analyzed from an epidemiologic viewpoint.Logistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Polymorphism, Genetic: The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.Health Services Research: The integration of epidemiologic, sociological, economic, and other analytic sciences in the study of health services. Health services research is usually concerned with relationships between need, demand, supply, use, and outcome of health services. The aim of the research is evaluation, particularly in terms of structure, process, output, and outcome. (From Last, Dictionary of Epidemiology, 2d ed)Data Collection: Systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data.Canada: The largest country in North America, comprising 10 provinces and three territories. Its capital is Ottawa.Multivariate Analysis: A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Hospitalization: The confinement of a patient in a hospital.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Registries: The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Infant, Newborn: An infant during the first month after birth.HIV Infections: Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).

Using physical-chemistry-based substitution models in phylogenetic analyses of HIV-1 subtypes. (1/6654)

HIV-1 subtype phylogeny is investigated using a previously developed computational model of natural amino acid site substitutions. This model, based on Boltzmann statistics and Metropolis kinetics, involves an order of magnitude fewer adjustable parameters than traditional substitution matrices and deals more effectively with the issue of protein site heterogeneity. When optimized for sequences of HIV-1 envelope (env) proteins from a few specific subtypes, our model is more likely to describe the evolutionary record for other subtypes than are methods using a single substitution matrix, even a matrix optimized over the same data. Pairwise distances are calculated between various probabilistic ancestral subtype sequences, and a distance matrix approach is used to find the optimal phylogenetic tree. Our results indicate that the relationships between subtypes B, C, and D and those between subtypes A and H may be closer than previously thought.  (+info)

Prehistoric birds from New Ireland, Papua New Guinea: extinctions on a large Melanesian island. (2/6654)

At least 50 species of birds are represented in 241 bird bones from five late Pleistocene and Holocene archaeological sites on New Ireland (Bismarck Archipelago, Papua New Guinea). The bones include only two of seabirds and none of migrant shorebirds or introduced species. Of the 50 species, at least 12 (petrel, hawk, megapode, quail, four rails, cockatoo, two owls, and crow) are not part of the current avifauna and have not been recorded previously from New Ireland. Larger samples of bones undoubtedly would indicate more extirpated species and refine the chronology of extinction. Humans have lived on New Ireland for ca. 35,000 years, whereas most of the identified bones are 15,000 to 6,000 years old. It is suspected that most or all of New Ireland's avian extinction was anthropogenic, but this suspicion remains undetermined. Our data show that significant prehistoric losses of birds, which are well documented on Pacific islands more remote than New Ireland, occurred also on large, high, mostly forested islands close to New Guinea.  (+info)

Ancestral origins and worldwide distribution of the PRNP 200K mutation causing familial Creutzfeldt-Jakob disease. (3/6654)

Creutzfeldt-Jakob disease (CJD) belongs to a group of prion diseases that may be infectious, sporadic, or hereditary. The 200K point mutation in the PRNP gene is the most frequent cause of hereditary CJD, accounting for >70% of families with CJD worldwide. Prevalence of the 200K variant of familial CJD is especially high in Slovakia, Chile, and Italy, and among populations of Libyan and Tunisian Jews. To study ancestral origins of the 200K mutation-associated chromosomes, we selected microsatellite markers flanking the PRNP gene on chromosome 20p12-pter and an intragenic single-nucleotide polymorphism at the PRNP codon 129. Haplotypes were constructed for 62 CJD families originating from 11 world populations. The results show that Libyan, Tunisian, Italian, Chilean, and Spanish families share a major haplotype, suggesting that the 200K mutation may have originated from a single mutational event, perhaps in Spain, and spread to all these populations with Sephardic migrants expelled from Spain in the Middle Ages. Slovakian families and a family of Polish origin show another unique haplotype. The haplotypes in families from Germany, Sicily, Austria, and Japan are different from the Mediterranean or eastern European haplotypes. On the basis of this study, we conclude that founder effect and independent mutational events are responsible for the current geographic distribution of hereditary CJD associated with the 200K mutation.  (+info)

mtDNA analysis of Nile River Valley populations: A genetic corridor or a barrier to migration? (4/6654)

To assess the extent to which the Nile River Valley has been a corridor for human migrations between Egypt and sub-Saharan Africa, we analyzed mtDNA variation in 224 individuals from various locations along the river. Sequences of the first hypervariable segment (HV1) of the mtDNA control region and a polymorphic HpaI site at position 3592 allowed us to designate each mtDNA as being of "northern" or "southern" affiliation. Proportions of northern and southern mtDNA differed significantly between Egypt, Nubia, and the southern Sudan. At slowly evolving sites within HV1, northern-mtDNA diversity was highest in Egypt and lowest in the southern Sudan, and southern-mtDNA diversity was highest in the southern Sudan and lowest in Egypt, indicating that migrations had occurred bidirectionally along the Nile River Valley. Egypt and Nubia have low and similar amounts of divergence for both mtDNA types, which is consistent with historical evidence for long-term interactions between Egypt and Nubia. Spatial autocorrelation analysis demonstrates a smooth gradient of decreasing genetic similarity of mtDNA types as geographic distance between sampling localities increases, strongly suggesting gene flow along the Nile, with no evident barriers. We conclude that these migrations probably occurred within the past few hundred to few thousand years and that the migration from north to south was either earlier or lesser in the extent of gene flow than the migration from south to north.  (+info)

Distribution of haplotypes from a chromosome 21 region distinguishes multiple prehistoric human migrations. (5/6654)

Despite mounting genetic evidence implicating a recent origin of modern humans, the elucidation of early migratory gene-flow episodes remains incomplete. Geographic distribution of haplotypes may show traces of ancestral migrations. However, such evolutionary signatures can be erased easily by recombination and mutational perturbations. A 565-bp chromosome 21 region near the MX1 gene, which contains nine sites frequently polymorphic in human populations, has been found. It is unaffected by recombination and recurrent mutation and thus reflects only migratory history, genetic drift, and possibly selection. Geographic distribution of contemporary haplotypes implies distinctive prehistoric human migrations: one to Oceania, one to Asia and subsequently to America, and a third one predominantly to Europe. The findings with chromosome 21 are confirmed by independent evidence from a Y chromosome phylogeny. Loci of this type will help to decipher the evolutionary history of modern humans.  (+info)

High recombination rate in natural populations of Plasmodium falciparum. (6/6654)

Malaria parasites are sexually reproducing protozoa, although the extent of effective meiotic recombination in natural populations has been debated. If meiotic recombination occurs frequently, compared with point mutation and mitotic rearrangement, linkage disequilibrium between polymorphic sites is expected to decline with increasing distance along a chromosome. The rate of this decline should be proportional to the effective meiotic recombination rate in the population. Multiple polymorphic sites covering a 5-kb region of chromosome 9 (the msp1 gene) have been typed in 547 isolates from six populations in Africa to test for such a decline and estimate its rate in populations of Plasmodium falciparum. The magnitude of two-site linkage disequilibrium declines markedly with increasing molecular map distance between the sites, reaching nonsignificant levels within a map range of 0.3-1.0 kb in five of the populations and over a larger map distance in the population with lowest malaria endemicity. The rate of decline in linkage disequilibrium over molecular map distance is at least as rapid as that observed in most chromosomal regions of other sexually reproducing eukaryotes, such as humans and Drosophila. These results are consistent with the effective recombination rate expected in natural populations of P. falciparum, predicted on the basis of the underlying molecular rate of meiotic crossover and the coefficient of inbreeding caused by self-fertilization events. This is conclusive evidence to reject any hypothesis of clonality or low rate of meiotic recombination in P. falciparum populations. Moreover, the data have major implications for the design and interpretation of population genetic studies of selection on P. falciparum genes.  (+info)

The modulation of DNA content: proximate causes and ultimate consequences. (7/6654)

The forces responsible for modulating the large-scale features of the genome remain one of the most difficult issues confronting evolutionary biology. Although diversity in chromosomal architecture, nucleotide composition, and genome size has been well documented, there is little understanding of either the evolutionary origins or impact of much of this variation. The 80,000-fold divergence in genome sizes among eukaryotes represents perhaps the greatest challenge for genomic holists. Although some researchers continue to characterize much variation in genome size as a mere by-product of an intragenomic selfish DNA "free-for-all" there is increasing evidence for the primacy of selection in molding genome sizes via impacts on cell size and division rates. Moreover, processes inducing quantum or doubling series variation in gametic or somatic genome sizes are common. These abrupt shifts have broad effects on phenotypic attributes at both cellular and organismal levels and may play an important role in explaining episodes of rapid-or even saltational-character state evolution.  (+info)

Identification of a distinct common strain of "Norwalk-like viruses" having a global distribution. (8/6654)

"Norwalk-like viruses" (NLVs) are the most common cause of outbreaks of nonbacterial gastroenteritis. During molecular surveillance of NLV strains from 152 outbreaks of gastroenteritis that occurred in the US between August 1993 and July 1997, we identified an NLV strain that predominated during the 1995-1996 season. The "95/96-US" strain caused 60 outbreaks in geographically distant locations within the US and was identified, by sequence comparisons, in an additional 7 countries on 5 continents during the same period. This is the first demonstration linking a single NLV strain globally and suggests that the circulation of these strains might involve patterns of transmission not previously considered. The diagnostic techniques are now available to establish a global network for surveillance of NLV strains that would highlight the importance of NLVs worldwide and allow molecular identification of common strains having a global distribution so as to consider interventions for their control.  (+info)

  • Regional geography courses, other than GEOG 110 World Regional Geography, are strongly recommended as related courses or free electives. (
  • The goal of this chapter is to describe the spatial geography of Cyberspace in terms of its technical manifestations, and in terms of the dominant conceptual narrative through which Cyberspace is understood. (
  • The spatial geography of Cyberspace is critical to understanding the larger thesis that Cyberspace recodes borders and reprograms the world. (
  • The central principle of the new geography established by Powell, Button, Gilbert, Davis, and other American geographers and geologists is the doctrine of a base level of erosion as the goal of the destructive processes. (
  • If you decide at the end of Year 1 that you want to specialise in Physical Geography, you can transfer (if your grades are sufficient) to the Geography BSc degree. (
  • Identify and describe the basic concepts, patterns and processes of physical geography that shape the patterns of Earth's surface. (
  • it rejects absolutely the category of the author of one of our textbooks in physical geography, that the air, the water, and the land are "the three dead geographic forms. (
  • During this degree, you will study some of the most pressing global and environmental challenges of our time, with particular emphasis on human, digital and environmental geographies. (
  • Esri just released a new sample vector basemap that is built specifically to make maps of subjects related to human geography. (
  • Just as the Topographic Basemap supports so many wonderful maps that require topography on a colorful basemap, the Human Geography Basemap is likewise tailored to make maps of human geography better. (
  • Human geography maps include thematic maps of statistical data, demographics, etc. (
  • The General Education Domain III-C (Global Competency, Ethical Reasoning, and/or Human Diversity) requirement is satisfied through the completion of the Geography major. (
  • The Bachelor of Arts in Geography emphasizes proficiency in human geography and develops skills in a foreign language. (
  • Settlement geography is a branch of human geography that investigates the earth's surface's part settled by humans. (
  • From the Amazon to Tibet, this Web site introduces us to geography with annotated clips from the film and notes from Dr. Cecil Keen, a professor of Geography at Minnesota State University Mankato. (
  • The concentrations shown below are designed to prepare a student for a career or further study in geography. (
  • The geologist who seeks, for example, the causes of volcanism, will find help in his study of the distribution and relative action of existing volcanoes-in other words, he can not keep from geography. (
  • It combines particularly well with other sciences and with Geography. (
  • The new movement has simply applied the evolutionary principle to geography, giving it the life and freedom which this doctrine has imparted to all other sciences in our day. (
  • Questions (and answers) from the National Geography Bee are posed daily at this web version of the popular "National Geographic" magazine. (
  • All students complete a core within Geography that provides a broad background in the discipline. (
  • Employ analytical and interpretive analysis and knowledge of major concepts, models and issues in the discipline of geography. (
  • Geography courses at NWACC encourage students to go beyond memorizing the names and locations of countries, cities, capitals and rivers. (
  • Geography Course Information Students will cover a wide range of topics and experience a variety of learning and teaching approaches. (
  • Geography majors may complete an approved minor through a combination of five (5) related elective courses and/or free electives. (
  • Many geography courses at NWACC carry transfer credit to four-year institutions and can fulfill general education requirements. (
  • With the skills you learn from your geography courses such as reading, analyzing data, synthesizing arguments and critical thinking, you will be a marketable individual and can move in many different career directions. (
  • In Years 2 and 3 we offer a wide range of modules that cover some of the most pressing global and environmental challenges of time, including: migration and how this shapes us and the places where we live, environmental governance and justice, climate change, gentrification, energy and food security, and critical development geographies and geopolitics. (
  • Unruh JD (2019 [2018 issue]) The geography of water and oil resource governance inpost-conflict Iraq. (
  • The United States National Section of the PanAmerican Institute for Geography and History (USNS-PAIGH) held this Meet-and-Greet event during the Annual Meeting of the Association of American Geographers (AAG) in Washington, DC on Friday, April 16, 2010. (
  • While individual geographers may practice only one kind of geography, many are conversant with two or all three branches. (
  • Due to a perceived lack of scientific rigor in an overly descriptive nature of the discipline, and a continued separation of geography from its two subfields of physical and human geography and from geology, geographers in the mid-20th century began to apply statistical and mathematical models in order to solve spatial problems. (
  • We are a lively, talented, and congenial group of faculty, students, and staff who occupy the Burchfiel Geography Building, built for us in 2000. (
  • We have just over 2000 graduates of the geography program since it was established in 1966. (
  • His accomplishments include experience as a high school staff member for the Colorado Alliance Summer Geography Institute, co-director of the Colorado Geographic Alliance AP Human Geography Institute in 2000 and 2001, and a Distinguished Teaching Achievement Award from the National Council for Geographic Education in 2000. (
  • Candidates whose undergraduate degree is not in geography will be required to complete some additional undergraduate program courses during their first year of study, in addition to the required graduate program courses. (
  • For many graduates of geography, the field course was the highlight of their undergraduate program. (
  • Undergraduate applicants must have completed at least 16 credits in geography. (
  • According to the 2020 Times Higher Education World University Rankings, UH Mānoa's geography and archaeology are in the top 40 among U.S. universities and colleges. (
  • Indian software suppliers have had to give UK companies lessons in geography following concerns that the war in Afghanistan could hit IT outsourcing work in India. (
  • This group was launched for Springer earth sciences, geography and environmental science authors including academics, researchers and professionals to facilitate discussions, share new publishing ideas, offer recommendations, and contribute insights to developments in the field. (
  • Central offers a Bachelor of Arts or a Bachelor of Science in Geography with specializations in geographic information science and environmental and resource geography. (
  • A Bachelor of Science in Physical Geography will have you exploring earth systems science by studying the interactions between air (atmosphere), water (hydrosphere), land (lithosphere) and the spaces where organisms live (biosphere). (
  • CWU offers networking and social opportunities through the Geographical Society including field trips, visiting speakers, and other activities relevant to the study of geography. (
  • The Royal Geographical Society was founded in England in 1830, although the United Kingdom did not get its first full Chair of geography until 1917. (
  • Horrible Geography: Odious Oceans, Violent Volcanoes and Stormy Weather won the Geographical Association Silver Award in 1999. (
  • Cambridge IGCSE and O Level Geography has been written specifically for Cambridge International syllabuses 0460 and 2217. (
  • Full teacher support to accompany the Collins Cambridge IGCSE Geography Student Book - the Teacher Guide content is matched lesson-by-lesson to the Student Book. (
  • During this degree, you will study some of the most pressing global and environmental challenges of our time, with particular emphasis on human, digital and environmental geographies. (
  • In Years 2 and 3 we offer a wide range of modules that cover some of the most pressing global and environmental challenges of time, including: migration and how this shapes us and the places where we live, environmental governance and justice, climate change, gentrification, energy and food security, and critical development geographies and geopolitics. (
  • Geography looks for patterns in the distribution of diverse phenomena, and it tries to explain their variation by examining a wide range of underlying environmental and socioeconomic factors. (
  • Physical geography can be divided into many broad categories, including: Biogeography Climatology & meteorology Coastal geography Environmental management Geodesy Geomorphology Glaciology Hydrology & hydrography Landscape ecology Oceanography Pedology Palaeogeography Quaternary science Human geography is a branch of geography that focuses on the study of patterns and processes that shape the human society. (
  • This connection between both physical and human properties of geography is most apparent in the theory of environmental determinism, made popular in the 19th century by Carl Ritter and others, and has close links to the field of evolutionary biology of the time. (
  • With links to (possibilism) (geography) and cultural ecology some of the same notions of causal effect of the environment on society and culture remain with environmental determinism. (
  • is an introduction to the study of culture in geography, emphasizing both the history of the field from classic studies of landscapes to contemporary scholarship and themes of recent importance. (
  • Behavioral geography emerged for some time as a means to understand how people made perceived spaces and places, and made locational decisions. (
  • Sir, - With the removal of history and geography as Junior Cycle core subjects, is the Government hoping for a new generation of citizens who don't know who they are, where they are from, and why things are the way they are? (
  • Brush up on your geography and finally learn what countries are in Eastern Europe with our maps. (
  • At CWU, geography is more than maps and charts-it is a vibrant field of study that involves hands-on, real-life involvement in finding solutions that will enhance the future. (
  • These maps (or something very similar) can also be found at (Archives of Ontario online presentation: The Changing Shape of Ontario). (
  • The event was hosted by the AAG and the US National Section Geography Commission during the world's largest academic and scientific disciplinary conference, attended by an estimated 8,200 scholars and practitioners from more than 75 countries. (
  • Geography is unusual among academic disciplines for being fundamentally interdisciplinary. (
  • We are pleased that you are interested in graduate studies in Geography at the University of Kentucky. (
  • A statement of your goals and objectives in which you discuss your areas of scholarly interest, any research directions you may wish to pursue, and how your interests and goals fit with those of the University of Kentucky's Graduate Program in Geography. (
  • Biodiversity and geography ," Thuenen-Series of Applied Economic Theory 79, University of Rostock, Institute of Economics. (
  • Elvin Delgado, CWU assistant professor of geography, is one of only five public university faculty members to receive the coveted Rep. Timm Ormsby Citizenship Award. (
  • From the Amazon to Tibet, this Web site introduces us to geography with annotated clips from the film and notes from Dr. Cecil Keen, a professor of Geography at Minnesota State University Mankato. (
  • I thought you might be interested in this item at Title: Kantian conceptual geography Author: Nathaniel Jason Goldberg Publisher: New York, NY : Oxford University Press, 2015. (
  • A total of 6 graduate credits from an accredited institution may be transferred into the Geography and Urban Studies program. (
  • Australian Statistical Geography Standard (ASGS) Volume 4 - Significant Urban Areas, Urban Centres and Localities, Section of State (cat no. 1270.0.55.004). (
  • Canvases current research topics, methods, and theoretical debates in urban geography. (