Sexual Behavior: Sexual activities of humans.Sexual Behavior, Animal: Sexual activities of animals.Risk-Taking: Undertaking a task involving a challenge for achievement or a desirable goal in which there is a lack of certainty or a fear of failure. It may also include the exhibiting of certain behaviors whose outcomes may present a risk to the individual or to those associated with him or her.Sexual Partners: Married or single individuals who share sexual relations.Copulation: Sexual union of a male and a female in non-human species.Behavior, Animal: The observable response an animal makes to any situation.Unsafe Sex: Sexual behaviors which are high-risk for contracting SEXUALLY TRANSMITTED DISEASES or for producing PREGNANCY.Condoms: A sheath that is worn over the penis during sexual behavior in order to prevent pregnancy or spread of sexually transmitted disease.Sexually Transmitted Diseases: Diseases due to or propagated by sexual contact.Adolescent Behavior: Any observable response or action of an adolescent.Sexual Abstinence: Refraining from SEXUAL INTERCOURSE.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.Coitus: The sexual union of a male and a female, a term used for human only.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).Homosexuality, Male: Sexual attraction or relationship between males.Social Behavior: Any behavior caused by or affecting another individual, usually of the same species.Safe Sex: Sexual behavior that prevents or reduces the spread of SEXUALLY TRANSMITTED DISEASES or PREGNANCY.Health Behavior: Behaviors expressed by individuals to protect, maintain or promote their health status. For example, proper diet, and appropriate exercise are activities perceived to influence health status. Life style is closely associated with health behavior and factors influencing life style are socioeconomic, educational, and cultural.Health Knowledge, Attitudes, Practice: Knowledge, attitudes, and associated behaviors which pertain to health-related topics such as PATHOLOGIC PROCESSES or diseases, their prevention, and treatment. This term refers to non-health workers and health workers (HEALTH PERSONNEL).Ejaculation: The emission of SEMEN to the exterior, resulting from the contraction of muscles surrounding the male internal urogenital ducts.Behavior: The observable response of a man or animal to a situation.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.Contraceptive Devices, Male: Contraceptive devices used by males.Preoptic Area: Region of hypothalamus between the ANTERIOR COMMISSURE and OPTIC CHIASM.Heterosexuality: The sexual attraction or relationship between members of the opposite SEX.Bisexuality: The sexual attraction or relationship between members of both the same and the opposite SEX.Substance-Related Disorders: Disorders related to substance abuse.Exploratory Behavior: The tendency to explore or investigate a novel environment. It is considered a motivation not clearly distinguishable from curiosity.Agonistic Behavior: Any behavior associated with conflict between two individuals.Sex Education: Education which increases the knowledge of the functional, structural, and behavioral aspects of human reproduction.Sexuality: The sexual functions, activities, attitudes, and orientations of an individual. Sexuality, male or female, becomes evident at PUBERTY under the influence of gonadal steroids (TESTOSTERONE or ESTRADIOL), and social effects.Homosexuality: The sexual attraction or relationship between members of the same SEX.Prostitution: The practice of indulging in sexual relations for money.Extramarital Relations: Voluntary SEXUAL INTERCOURSE between a married person and someone other than the SPOUSE.Child Behavior: Any observable response or action of a child from 24 months through 12 years of age. For neonates or children younger than 24 months, INFANT BEHAVIOR is available.Aphrodisiacs: Chemical agents or odors that stimulate sexual desires. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Students: Individuals enrolled in a school or formal educational program.Religion and SexContraception Behavior: Behavior patterns of those practicing CONTRACEPTION.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.Aggression: Behavior which may be manifested by destructive and attacking action which is verbal or physical, by covert attitudes of hostility or by obstructionism.Maternal Behavior: The behavior patterns associated with or characteristic of a mother.Risk Reduction Behavior: Reduction of high-risk choices and adoption of low-risk quantity and frequency alternatives.Peer Group: Group composed of associates of same species, approximately the same age, and usually of similar rank or social status.Courtship: Activities designed to attract the attention or favors of another.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.Consummatory Behavior: An act which constitutes the termination of a given instinctive behavior pattern or sequence.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.HIV Seropositivity: Development of neutralizing antibodies in individuals who have been exposed to the human immunodeficiency virus (HIV/HTLV-III/LAV).Compulsive Behavior: The behavior of performing an act persistently and repetitively without it leading to reward or pleasure. The act is usually a small, circumscribed behavior, almost ritualistic, yet not pathologically disturbing. Examples of compulsive behavior include twirling of hair, checking something constantly, not wanting pennies in change, straightening tilted pictures, etc.Child Behavior Disorders: Disturbances considered to be pathological based on age and stage appropriateness, e.g., conduct disturbances and anaclitic depression. This concept does not include psychoneuroses, psychoses, or personality disorders with fixed patterns.Paraphilias: Disorders that include recurrent, intense sexually arousing fantasies, sexual urges, or behaviors generally involving nonhuman objects, suffering of oneself or partners, or children or other nonconsenting partners. (from DSM-IV, 1994)Interpersonal Relations: The reciprocal interaction of two or more persons.Interviews as Topic: Conversations with an individual or individuals held in order to obtain information about their background and other personal biographical data, their attitudes and opinions, etc. It includes school admission or job interviews.Behavior Therapy: The application of modern theories of learning and conditioning in the treatment of behavior disorders.Sex Characteristics: Those characteristics that distinguish one SEX from the other. The primary sex characteristics are the OVARIES and TESTES and their related hormones. Secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction.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.Testosterone: A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.Stereotyped Behavior: Relatively invariant mode of behavior elicited or determined by a particular situation; may be verbal, postural, or expressive.Urban Population: The inhabitants of a city or town, including metropolitan areas and suburban areas.African Americans: Persons living in the United States having origins in any of the black groups of Africa.Erotica: Literary or artistic items having an erotic theme. It refers especially to books treating sexual love in a sensuous or voluptuous manner. (Webster, 3d ed)Socioeconomic Factors: Social and economic factors that characterize the individual or group within the social structure.Self Disclosure: A willingness to reveal information about oneself to others.Orgasm: The climax of sexual excitement in either humans or animals.Universities: Educational institutions providing facilities for teaching and research and authorized to grant academic degrees.Single Person: The unmarried man or woman.Longitudinal Studies: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.Coturnix: A genus of BIRDS in the family Phasianidae, order GALLIFORMES, containing the common European and other Old World QUAIL.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Social Environment: The aggregate of social and cultural institutions, forms, patterns, and processes that influence the life of an individual or community.Alcohol Drinking: Behaviors associated with the ingesting of alcoholic beverages, including social drinking.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.South Africa: A republic in southern Africa, the southernmost part of Africa. It has three capitals: Pretoria (administrative), Cape Town (legislative), and Bloemfontein (judicial). Officially the Republic of South Africa since 1960, it was called the Union of South Africa 1910-1960.Appetitive Behavior: Animal searching behavior. The variable introductory phase of an instinctive behavior pattern or sequence, e.g., looking for food, or sequential courtship patterns prior to mating.Homosexuality, Female: Sexual attraction or relationship between females.United StatesAcquired Immunodeficiency Syndrome: An acquired defect of cellular immunity associated with infection by the human immunodeficiency virus (HIV), a CD4-positive T-lymphocyte count under 200 cells/microliter or less than 14% of total lymphocytes, and increased susceptibility to opportunistic infections and malignant neoplasms. Clinical manifestations also include emaciation (wasting) and dementia. These elements reflect criteria for AIDS as defined by the CDC in 1993.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.Motivation: Those factors which cause an organism to behave or act in either a goal-seeking or satisfying manner. They may be influenced by physiological drives or by external stimuli.Health Surveys: A systematic collection of factual data pertaining to health and disease in a human population within a given geographic area.Gender Identity: A person's concept of self as being male and masculine or female and feminine, or ambivalent, based in part on physical characteristics, parental responses, and psychological and social pressures. It is the internal experience of gender role.Sexually Transmitted Diseases, Viral: Viral diseases which are transmitted or propagated by sexual conduct.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Parent-Child Relations: The interactions between parent and child.Uganda: A republic in eastern Africa, south of SUDAN and west of KENYA. Its capital is Kampala.Attitude to Health: Public attitudes toward health, disease, and the medical care system.Rural Population: The inhabitants of rural areas or of small towns classified as rural.Substance Abuse, Intravenous: Abuse, overuse, or misuse of a substance by its injection into a vein.Social Values: Abstract standards or empirical variables in social life which are believed to be important and/or desirable.Choice Behavior: The act of making a selection among two or more alternatives, usually after a period of deliberation.Nesting Behavior: Animal behavior associated with the nest; includes construction, effects of size and material; behavior of the adult during the nesting period and the effect of the nest on the behavior of the young.Amyl Nitrite: A vasodilator that is administered by inhalation. It is also used recreationally due to its supposed ability to induce euphoria and act as an aphrodisiac.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.HIV Seroprevalence: Studies of the number of cases where human immunodeficiency virus (HIV) is present in a specific population at a designated time. The presence in a given individual is determined by the finding of HIV antibodies in the serum (HIV SEROPOSITIVITY).Ventromedial Hypothalamic Nucleus: A nucleus of the middle hypothalamus, the largest cell group of the tuberal region with small-to-medium size cells.HIV Seronegativity: Immune status consisting of non-production of HIV antibodies, as determined by various serological tests.Holidays: Days commemorating events. Holidays also include vacation periods.Orchiectomy: The surgical removal of one or both testicles.Impulsive Behavior: An act performed without delay, reflection, voluntary direction or obvious control in response to a stimulus.Drinking Behavior: Behaviors associated with the ingesting of water and other liquids; includes rhythmic patterns of drinking (time intervals - onset and duration), frequency and satiety.Social Desirability: A personality trait rendering the individual acceptable in social or interpersonal relations. It is related to social acceptance, social approval, popularity, social status, leadership qualities, or any quality making him a socially desirable companion.Sex: The totality of characteristics of reproductive structure, functions, PHENOTYPE, and GENOTYPE, differentiating the MALE from the FEMALE organism.Social Conformity: Behavioral or attitudinal compliance with recognized social patterns or standards.Health Education: Education that increases the awareness and favorably influences the attitudes and knowledge relating to the improvement of health on a personal or community basis.Men: Human males as cultural, psychological, sociological, political, and economic entities.Methamphetamine: A central nervous system stimulant and sympathomimetic with actions and uses similar to DEXTROAMPHETAMINE. The smokable form is a drug of abuse and is referred to as crank, crystal, crystal meth, ice, and speed.Incest: Sexual intercourse between persons so closely related that they are forbidden by law to marry.Time Factors: Elements of limited time intervals, contributing to particular results or situations.GeorgiaSex Differentiation: The process in developing sex- or gender-specific tissue, organ, or function after SEX DETERMINATION PROCESSES have set the sex of the GONADS. Major areas of sex differentiation occur in the reproductive tract (GENITALIA) and the brain.Zimbabwe: A republic in southern Africa, east of ZAMBIA and BOTSWANA and west of MOZAMBIQUE. Its capital is Harare. It was formerly called Rhodesia and Southern Rhodesia.FloridaLibido: The psychic drive or energy associated with sexual instinct in the broad sense (pleasure and love-object seeking). It may also connote the psychic energy associated with instincts in general that motivate behavior.Parenting: Performing the role of a parent by care-giving, nurturance, and protection of the child by a natural or substitute parent. The parent supports the child by exercising authority and through consistent, empathic, appropriate behavior in response to the child's needs. PARENTING differs from CHILD REARING in that in child rearing the emphasis is on the act of training or bringing up the children and the interaction between the parent and child, while parenting emphasizes the responsibility and qualities of exemplary behavior of the parent.Self-Injurious Behavior: Behavior in which persons hurt or harm themselves without the motive of suicide or of sexual deviation.Gonorrhea: Acute infectious disease characterized by primary invasion of the urogenital tract. The etiologic agent, NEISSERIA GONORRHOEAE, was isolated by Neisser in 1879.Ovariectomy: The surgical removal of one or both ovaries.Papillomavirus Infections: Neoplasms of the skin and mucous membranes caused by papillomaviruses. They are usually benign but some have a high risk for malignant progression.San FranciscoPregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Rats, Long-Evans: An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.Coercion: The use of force or intimidation to obtain compliance.Sex Attractants: Pheromones that elicit sexual attraction or mating behavior usually in members of the opposite sex in the same species.New York CityMasturbation: Sexual stimulation or gratification of the self.Health Promotion: Encouraging consumer behaviors most likely to optimize health potentials (physical and psychosocial) through health information, preventive programs, and access to medical care.Models, Psychological: Theoretical representations that simulate psychological processes and/or social processes. These include the use of mathematical equations, computers, and other electronic equipment.Syphilis: A contagious venereal disease caused by the spirochete TREPONEMA PALLIDUM.Estradiol: The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids.Anxiety: Feeling or emotion of dread, apprehension, and impending disaster but not disabling as with ANXIETY DISORDERS.Pregnancy in Adolescence: Pregnancy in human adolescent females under the age of 19.Social Behavior Disorders: Behaviors which are at variance with the expected social norm and which affect other individuals.Love: Affection; in psychiatry commonly refers to pleasure, particularly as it applies to gratifying experiences between individuals.Predatory Behavior: Instinctual behavior pattern in which food is obtained by killing and consuming other species.Marriage: The social institution involving legal and/or religious sanction whereby individuals are joined together.Sexual Development: The processes of anatomical and physiological changes related to sexual or reproductive functions during the life span of a human or an animal, from FERTILIZATION to DEATH. These include SEX DETERMINATION PROCESSES; SEX DIFFERENTIATION; SEXUAL MATURATION; and changes during AGING.Sexually Transmitted Diseases, Bacterial: Bacterial diseases transmitted or propagated by sexual conduct.Violence: Individual or group aggressive behavior which is socially non-acceptable, turbulent, and often destructive. It is precipitated by frustrations, hostility, prejudices, etc.Tanzania: A republic in eastern Africa, south of UGANDA and north of MOZAMBIQUE. Its capital is Dar es Salaam. It was formed in 1964 by a merger of the countries of TANGANYIKA and ZANZIBAR.Child Abuse, Sexual: Sexual maltreatment of the child or minor.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Behavior, Addictive: The observable, measurable, and often pathological activity of an organism that portrays its inability to overcome a habit resulting in an insatiable craving for a substance or for performing certain acts. The addictive behavior includes the emotional and physical overdependence on the object of habit in increasing amount or frequency.Urban Health: The status of health in urban populations.Sex Workers: People who engage in occupational sexual behavior in exchange for economic rewards or other extrinsic considerations.Reproduction: The total process by which organisms produce offspring. (Stedman, 25th ed)Kenya: A republic in eastern Africa, south of ETHIOPIA, west of SOMALIA with TANZANIA to its south, and coastline on the Indian Ocean. Its capital is Nairobi.PrisonersTransgendered Persons: Persons having a sense of persistent identification with, and expression of, gender-coded behaviors not typically associated with one's anatomical sex at birth, and with or without a desire to undergo SEX REASSIGNMENT PROCEDURES.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.Vomeronasal Organ: An accessory chemoreceptor organ that is separated from the main OLFACTORY MUCOSA. It is situated at the base of nasal septum close to the VOMER and NASAL BONES. It forwards chemical signals (such as PHEROMONES) to the CENTRAL NERVOUS SYSTEM, thus influencing reproductive and social behavior. In humans, most of its structures except the vomeronasal duct undergo regression after birth.Sampling Studies: Studies in which a number of subjects are selected from all subjects in a defined population. Conclusions based on sample results may be attributed only to the population sampled.Sexual Dysfunction, Physiological: Physiological disturbances in normal sexual performance in either the male or the female.Permissiveness: The attitude that grants freedom of expression and activity to another individual, but not necessarily with sanction or approval.Juvenile Delinquency: The antisocial acts of children or persons under age which are illegal or lawfully interpreted as constituting delinquency.Ambulatory Care Facilities: Those facilities which administer health services to individuals who do not require hospitalization or institutionalization.Contraception: Prevention of CONCEPTION by blocking fertility temporarily, or permanently (STERILIZATION, REPRODUCTIVE). Common means of reversible contraception include NATURAL FAMILY PLANNING METHODS; CONTRACEPTIVE AGENTS; or CONTRACEPTIVE DEVICES.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.Illness Behavior: Coordinate set of non-specific behavioral responses to non-psychiatric illness. These may include loss of APPETITE or LIBIDO; disinterest in ACTIVITIES OF DAILY LIVING; or withdrawal from social interaction.Genitalia, Male: The male reproductive organs. They are divided into the external organs (PENIS; SCROTUM;and URETHRA) and the internal organs (TESTIS; EPIDIDYMIS; VAS DEFERENS; SEMINAL VESICLES; EJACULATORY DUCTS; PROSTATE; and BULBOURETHRAL GLANDS).China: A country spanning from central Asia to the Pacific Ocean.Rural Health: The status of health in rural populations.Reproductive Behavior: Human behavior or decision related to REPRODUCTION.Castration: Surgical removal or artificial destruction of gonads.Student Health Services: Health services for college and university students usually provided by the educational institution.Sex Counseling: Advice and support given to individuals to help them understand and resolve their sexual adjustment problems. It excludes treatment for PSYCHOSEXUAL DISORDERS or PSYCHOSEXUAL DYSFUNCTION.Sexual Dysfunctions, Psychological: Disturbances in sexual desire and the psychophysiologic changes that characterize the sexual response cycle and cause marked distress and interpersonal difficulty. (APA, DSM-IV, 1994)Penile Erection: The state of the PENIS when the erectile tissue becomes filled or swollen (tumid) with BLOOD and causes the penis to become rigid and elevated. It is a complex process involving CENTRAL NERVOUS SYSTEM; PERIPHERAL NERVOUS SYSTEMS; HORMONES; SMOOTH MUSCLES; and vascular functions.Hypothalamus: Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.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.Aromatase: An enzyme that catalyzes the desaturation (aromatization) of the ring A of C19 androgens and converts them to C18 estrogens. In this process, the 19-methyl is removed. This enzyme is membrane-bound, located in the endoplasmic reticulum of estrogen-producing cells of ovaries, placenta, testes, adipose, and brain tissues. Aromatase is encoded by the CYP19 gene, and functions in complex with NADPH-FERRIHEMOPROTEIN REDUCTASE in the cytochrome P-450 system.Street Drugs: Drugs obtained and often manufactured illegally for the subjective effects they are said to produce. They are often distributed in urban areas, but are also available in suburban and rural areas, and tend to be grossly impure and may cause unexpected toxicity.Attitude: An enduring, learned predisposition to behave in a consistent way toward a given class of objects, or a persistent mental and/or neural state of readiness to react to a certain class of objects, not as they are but as they are conceived to be.Intention: What a person has in mind to do or bring about.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Sex Offenses: Any violation of established legal or moral codes in respect to sexual behavior.Herpes Genitalis: Infection of the genitals (GENITALIA) with HERPES SIMPLEX VIRUS in either the males or the females.Social Control, Informal: Those forms of control which are exerted in less concrete and tangible ways, as through folkways, mores, conventions, and public sentiment.Self Report: Method for obtaining information through verbal responses, written or oral, from subjects.Pheromones: Chemical substances, excreted by an organism into the environment, that elicit behavioral or physiological responses from other organisms of the same species. Perception of these chemical signals may be olfactory or by contact.Reproductive Health: The physical condition of human reproductive systems.Drug Users: People who take drugs for a non-therapeutic or non-medical effect. The drugs may be legal or illegal, but their use often results in adverse medical, legal, or social consequences for the users.ChicagoReward: An object or a situation that can serve to reinforce a response, to satisfy a motive, or to afford pleasure.Herpesvirus 2, Human: A species of SIMPLEXVIRUS associated with genital infections (HERPES GENITALIS). It is transmitted by sexual intercourse and close personal contact.Pleasure: Sensation of enjoyment or gratification.Circumcision, Male: Excision of the prepuce of the penis (FORESKIN) or part of it.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Zambia: A republic in southern Africa, south of DEMOCRATIC REPUBLIC OF THE CONGO and TANZANIA, and north of ZIMBABWE. Its capital is Lusaka. It was formerly called Northern Rhodesia.Sexual Maturation: Achievement of full sexual capacity in animals and in humans.AIDS Serodiagnosis: Immunologic tests for identification of HIV (HTLV-III/LAV) antibodies. They include assays for HIV SEROPOSITIVITY and HIV SERONEGATIVITY that have been developed for screening persons carrying the viral antibody from patients with overt symptoms of AIDS or AIDS-RELATED COMPLEX.Amygdala: Almond-shaped group of basal nuclei anterior to the INFERIOR HORN OF THE LATERAL VENTRICLE of the TEMPORAL LOBE. The amygdala is part of the limbic system.Nucleus Accumbens: Collection of pleomorphic cells in the caudal part of the anterior horn of the LATERAL VENTRICLE, in the region of the OLFACTORY TUBERCLE, lying between the head of the CAUDATE NUCLEUS and the ANTERIOR PERFORATED SUBSTANCE. It is part of the so-called VENTRAL STRIATUM, a composite structure considered part of the BASAL GANGLIA.Social Perception: The perceiving of attributes, characteristics, and behaviors of one's associates or social groups.Transients and Migrants: People who frequently change their place of residence.Malawi: A republic in southern Africa east of ZAMBIA and MOZAMBIQUE. Its capital is Lilongwe. It was formerly called Nyasaland.Posture: The position or attitude of the body.Homeless Youth: Runaway and homeless children and adolescents living on the streets of cities and having no fixed place of residence.Naval Medicine: The practice of medicine concerned with conditions affecting the health of individuals associated with the marine environment.Fertility: The capacity to conceive or to induce conception. It may refer to either the male or female.Liberia: A republic in western Africa, south of GUINEA and east of COTE D'IVOIRE. Its capital is Monrovia.