Periodic movement of human settlement from one geographical location to another.
The process of leaving one's country to establish residence in a foreign country.
The period of history before 500 of the common era.
The general name for NORTH AMERICA; CENTRAL AMERICA; and SOUTH AMERICA unspecified or combined.
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)
The geographical area of Africa comprising ALGERIA; EGYPT; LIBYA; MOROCCO; and TUNISIA. It includes also the vast deserts and oases of the Sahara. It is often referred to as North Africa, French-speaking Africa, or the Maghreb. (From Webster's New Geographical Dictionary, 1988, p856)
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.
The human male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans.
The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.
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.
The relationships of groups of organisms as reflected by their genetic makeup.
Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.
The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
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.
Genotypic differences observed among individuals in a population.
A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.
The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.
The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.
Periodic movements of animals in response to seasonal changes or reproductive instinct. Hormonal changes are the trigger in at least some animals. Most migrations are made for reasons of climatic change, feeding, or breeding.
The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.
The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.
Phenomenon of cell-mediated immunity measured by in vitro inhibition of the migration or phagocytosis of antigen-stimulated LEUKOCYTES or MACROPHAGES. Specific CELL MIGRATION ASSAYS have been developed to estimate levels of migration inhibitory factors, immune reactivity against tumor-associated antigens, and immunosuppressive effects of infectious microorganisms.
Migration of a foreign body from its original location to some other location in the body.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
Adherence of cells to surfaces or to other cells.
Specific assays that measure the migration of cells. They are commonly used to measure the migration of immune cells in response to stimuli and the inhibition of immune cell migration by immunosuppressive factors.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Proteins released by sensitized LYMPHOCYTES and possibly other cells that inhibit the migration of MACROPHAGES away from the release site. The structure and chemical properties may vary with the species and type of releasing cell.
The movement of cells or organisms toward or away from a substance in response to its concentration gradient.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
The passage of cells across the layer of ENDOTHELIAL CELLS, i.e., the ENDOTHELIUM; or across the layer of EPITHELIAL CELLS, i.e. the EPITHELIUM.
The movement of leukocytes in response to a chemical concentration gradient or to products formed in an immunologic reaction.
All of the processes involved in increasing CELL NUMBER including CELL DIVISION.
A cell line derived from cultured tumor cells.
Restoration of integrity to traumatized tissue.
A course or method of action selected, usually by an organization, institution, university, society, etc., from among alternatives to guide and determine present and future decisions and positions on matters of public interest or social concern. It does not include internal policy relating to organization and administration within the corporate body, for which ORGANIZATION AND ADMINISTRATION is available.
A plant genus in the CHENOPODIACEAE family.
Sudden onset water phenomena with different speed of occurrence. These include flash floods, seasonal river floods, and coastal floods, associated with CYCLONIC STORMS; TIDALWAVES; and storm surges.
The flow of water in enviromental bodies of water such as rivers, oceans, water supplies, aquariums, etc. It includes currents, tides, and waves.
Any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). It may result from natural factors such as changes in the sun's intensity, natural processes within the climate system such as changes in ocean circulation, or human activities.
A country in northern Africa, bordering the Mediterranean Sea, between Egypt, Tunisia, and Algeria, having southern border with Chad, Niger, and Sudan. Its capital is Tripoli.
The rights of the individual to cultural, social, economic, and educational opportunities as provided by society, e.g., right to work, right to education, and right to social security.
The intentional infliction of physical or mental suffering upon an individual or individuals, including the torture of animals.
Large vessels propelled by power or sail used for transportation on rivers, seas, oceans, or other navigable waters. Boats are smaller vessels propelled by oars, paddles, sail, or power; they may or may not have a deck.
Deliberate maltreatment of groups of humans beings including violations of generally-accepted fundamental rights as stated by the Universal Declaration of Human Rights, adopted and proclaimed by the United Nations General Assembly resolution 217 A (III) of 10 December 1948.
People who frequently change their place of residence.
The process by which a person or group of persons comes to be regarded or treated as lacking in human qualities.
The distinctly human attributes and attainments of a particular society.
A series of actions, sometimes symbolic actions which may be associated with a behavior pattern, and are often indispensable to its performance.
The period of history from the year 500 through 1450 of the common era.
Bodies preserved either by the ancient Egyptian technique or due to chance under favorable climatic conditions.
The scientific study of past societies through artifacts, fossils, etc.