Infant Mortality: Postnatal deaths from BIRTH to 365 days after birth in a given population. Postneonatal mortality represents deaths between 28 days and 365 days after birth (as defined by National Center for Health Statistics). Neonatal mortality represents deaths from birth to 27 days after birth.Infant, Newborn: An infant during the first month after birth.Mortality: All deaths reported in a given population.Infant, Premature: A human infant born before 37 weeks of GESTATION.Birth Certificates: Official certifications by a physician recording the individual's birth date, place of birth, parentage and other required identifying data which are filed with the local registrar of vital statistics.Infant, Low Birth Weight: An infant having a birth weight of 2500 gm. (5.5 lb.) or less but INFANT, VERY LOW BIRTH WEIGHT is available for infants having a birth weight of 1500 grams (3.3 lb.) or less.Cause of Death: Factors which produce cessation of all vital bodily functions. They can be analyzed from an epidemiologic viewpoint.Infant Care: Care of infants in the home or institution.Death Certificates: Official records of individual deaths including the cause of death certified by a physician, and any other required identifying information.Sudden Infant Death: The abrupt and unexplained death of an apparently healthy infant under one year of age, remaining unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history. (Pediatr Pathol 1991 Sep-Oct;11(5):677-84)Birth Weight: The mass or quantity of heaviness of an individual at BIRTH. It is expressed by units of pounds or kilograms.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Congenital Abnormalities: Malformations of organs or body parts during development in utero.Infant, Premature, DiseasesMaternal Age: The age of the mother in PREGNANCY.Fetal Mortality: Number of fetal deaths with stated or presumed gestation of 20 weeks or more in a given population. Late fetal mortality is death after of 28 weeks or more.Infant Food: Food processed and manufactured for the nutritional health of children in their first year of life.Vital Statistics: Used for general articles concerning statistics of births, deaths, marriages, etc.United StatesInfant, Newborn, Diseases: Diseases of newborn infants present at birth (congenital) or developing within the first month of birth. It does not include hereditary diseases not manifesting at birth or within the first 30 days of life nor does it include inborn errors of metabolism. Both HEREDITARY DISEASES and METABOLISM, INBORN ERRORS are available as general concepts.Prenatal Care: Care provided the pregnant woman in order to prevent complications, and decrease the incidence of maternal and prenatal mortality.Hospital Mortality: A vital statistic measuring or recording the rate of death from any cause in hospitalized populations.Fetal Death: Death of the developing young in utero. BIRTH of a dead FETUS is STILLBIRTH.Maternal Mortality: Maternal deaths resulting from complications of pregnancy and childbirth in a given population.Infant Formula: Liquid formulations for the nutrition of infants that can substitute for BREAST MILK.Infant, Very Low Birth Weight: An infant whose weight at birth is less than 1500 grams (3.3 lbs), regardless of gestational age.Infant Behavior: Any observable response or action of a neonate or infant up through the age of 23 months.Gestational Age: The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization.Perinatal Mortality: Deaths occurring from the 28th week of GESTATION to the 28th day after birth in a given population.Infant Welfare: Organized efforts by communities or organizations to improve the health and well-being of infants.Mothers: Female parents, human or animal.Birth Rate: The number of births in a given population per year or other unit of time.Ethnic Groups: A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.Developed Countries: Countries that have reached a level of economic achievement through an increase of production, per capita income and consumption, and utilization of natural and human resources.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.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.Breast Feeding: The nursing of an infant at the breast.Perinatal Care: The care of women and a fetus or newborn given before, during, and after delivery from the 28th week of gestation through the 7th day after delivery.Premature Birth: CHILDBIRTH before 37 weeks of PREGNANCY (259 days from the first day of the mother's last menstrual period, or 245 days after FERTILIZATION).Educational Status: Educational attainment or level of education of individuals.National Center for Health Statistics (U.S.): A center in the PUBLIC HEALTH SERVICE which is primarily concerned with the collection, analysis, and dissemination of health statistics on vital events and health activities to reflect the health status of people, health needs, and health resources.Life Expectancy: Based on known statistical data, the number of years which any person of a given age may reasonably expected to live.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Infant Nutritional Physiological Phenomena: Nutritional physiology of children from birth to 2 years of age.Socioeconomic Factors: Social and economic factors that characterize the individual or group within the social structure.Multiple Birth Offspring: The offspring in multiple pregnancies (PREGNANCY, MULTIPLE): TWINS; TRIPLETS; QUADRUPLETS; QUINTUPLETS; etc.European Continental Ancestry Group: Individuals whose ancestral origins are in the continent of Europe.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.Maternal Welfare: Organized efforts by communities or organizations to improve the health and well-being of the mother.Birth Order: The sequence in which children are born into the family.Illegitimacy: The state of birth outside of wedlock. It may refer to the offspring or the parents.Epidemiologic Factors: Events, characteristics, or other definable entities that have the potential to bring about a change in a health condition or other defined outcome.Pregnancy Outcome: Results of conception and ensuing pregnancy, including LIVE BIRTH; STILLBIRTH; SPONTANEOUS ABORTION; INDUCED ABORTION. The outcome may follow natural or artificial insemination or any of the various ASSISTED REPRODUCTIVE TECHNIQUES, such as EMBRYO TRANSFER or FERTILIZATION IN VITRO.Time Factors: Elements of limited time intervals, contributing to particular results or situations.BrazilCultural Deprivation: The absence of certain expected and acceptable cultural phenomena in the environment which results in the failure of the individual to communicate and respond in the most appropriate manner within the context of society. Language acquisition and language use are commonly used in assessing this concept.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Regional Medical Programs: Coordination of activities and programs among health care institutions within defined geographic areas for the purpose of improving delivery and quality of medical care to the patients. These programs are mandated under U.S. Public Law 89-239.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.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.Income: Revenues or receipts accruing from business enterprise, labor, or invested capital.Infant, Small for Gestational Age: An infant having a birth weight lower than expected for its gestational age.Slovakia: Created 1 January 1993 as a result of the division of Czechoslovakia into the Czech Republic and Slovakia.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)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.Proportional Hazards Models: Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.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.Pregnancy Complications: Conditions or pathological processes associated with pregnancy. They can occur during or after pregnancy, and range from minor discomforts to serious diseases that require medical interventions. They include diseases in pregnant females, and pregnancies in females with diseases.Residence Characteristics: Elements of residence that characterize a population. They are applicable in determining need for and utilization of health services.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.Stillbirth: The event that a FETUS is born dead or stillborn.Gravidity: The number of pregnancies, complete or incomplete, experienced by a female. It is different from PARITY, which is the number of offspring borne. (From Stedman, 26th ed)Developing Countries: Countries in the process of change with economic growth, that is, an increase in production, per capita consumption, and income. The process of economic growth involves better utilization of natural and human resources, which results in a change in the social, political, and economic structures.African Americans: Persons living in the United States having origins in any of the black groups of Africa.African Continental Ancestry Group: Individuals whose ancestral origins are in the continent of Africa.Continental Population Groups: Groups of individuals whose putative ancestry is from native continental populations based on similarities in physical appearance.Demography: Statistical interpretation and description of a population with reference to distribution, composition, or structure.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.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Survival Analysis: A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.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.ChileRisk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.Urban Health: The status of health in urban populations.Survival Rate: The proportion of survivors in a group, e.g., of patients, studied and followed over a period, or the proportion of persons in a specified group alive at the beginning of a time interval who survive to the end of the interval. It is often studied using life table methods.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.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.Social Conditions: The state of society as it exists or in flux. While it usually refers to society as a whole in a specified geographical or political region, it is applicable also to restricted strata of a society.Nunavut: A self-governing territory formed from the central and eastern portions of the Northwest Territories. It was officially established April 1, 1999. The capital is Iqaluit.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.Gypsies: Ethnic group originating in India and entering Europe in the 14th or 15th century.Urban Population: The inhabitants of a city or town, including metropolitan areas and suburban areas.Morbidity: The proportion of patients with a particular disease during a given year per given unit of population.Infant, Extremely Low Birth Weight: An infant whose weight at birth is less than 1000 grams (2.2 lbs), regardless of GESTATIONAL AGE.Registries: The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.Infectious Disease Transmission, Vertical: The transmission of infectious disease or pathogens from one generation to another. It includes transmission in utero or intrapartum by exposure to blood and secretions, and postpartum exposure via breastfeeding.SyriaCities: A large or important municipality of a country, usually a major metropolitan center.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.Rural Population: The inhabitants of rural areas or of small towns classified as rural.AlaskaParity: The number of offspring a female has borne. It is contrasted with GRAVIDITY, which refers to the number of pregnancies, regardless of outcome.NepalSanitation: The development and establishment of environmental conditions favorable to the health of the public.Delivery, Obstetric: Delivery of the FETUS and PLACENTA under the care of an obstetrician or a health worker. Obstetric deliveries may involve physical, psychological, medical, or surgical interventions.Inuits: Inuktitut-speakers generally associated with the northern polar region.Health Surveys: A systematic collection of factual data pertaining to health and disease in a human population within a given geographic area.History, 18th Century: Time period from 1701 through 1800 of the common era.Social Welfare: Organized institutions which provide services to ameliorate conditions of need or social pathology in the community.Arabs: Members of a Semitic people inhabiting the Arabian peninsula or other countries of the Middle East and North Africa. The term may be used with reference to ancient, medieval, or modern ethnic or cultural groups. (From Random House Unabridged Dictionary, 2d ed)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.Child Development: The continuous sequential physiological and psychological maturing of an individual from birth up to but not including ADOLESCENCE.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.Pregnancy Complications, Infectious: The co-occurrence of pregnancy and an INFECTION. The infection may precede or follow FERTILIZATION.Triplets: Three individuals derived from three FETUSES that were fertilized at or about the same time, developed in the UTERUS simultaneously, and born to the same mother.Rural Health: The status of health in rural populations.Milk, HumanProbability Theory: The branch of mathematics dealing with the purely logical properties of probability. Its theorems underlie most statistical methods. (Last, A Dictionary of Epidemiology, 2d ed)WalesNicaraguaMaternal Health Services: Organized services to provide health care to expectant and nursing mothers.EnglandGuinea-Bissau: A republic in western Africa, south of SENEGAL and west of GUINEA. Its capital is Bissau.Odds Ratio: The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.United States Public Health Service: A constituent organization of the DEPARTMENT OF HEALTH AND HUMAN SERVICES concerned with protecting and improving the health of the nation.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)Public Health Practice: The activities and endeavors of the public health services in a community on any level.Child Welfare: Organized efforts by communities or organizations to improve the health and well-being of the child.Infant, Extremely Premature: A human infant born before 28 weeks of GESTATION.Confidence Intervals: A range of values for a variable of interest, e.g., a rate, constructed so that this range has a specified probability of including the true value of the variable.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.MissouriHealth Status Indicators: The measurement of the health status for a given population using a variety of indices, including morbidity, mortality, and available health resources.Asphyxia Neonatorum: Respiratory failure in the newborn. (Dorland, 27th ed)Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.Longitudinal Studies: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.Cardiovascular Diseases: Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.Canada: The largest country in North America, comprising 10 provinces and three territories. Its capital is Ottawa.Indians, North American: Individual members of North American ethnic groups with ancient historic ancestral origins in Asia.Bottle Feeding: Use of nursing bottles for feeding. Applies to humans and animals.Intensive Care Units, Neonatal: Hospital units providing continuing surveillance and care to acutely ill newborn infants.Mortality, Premature: Deaths that occur before LIFE EXPECTANCY is reached within a given population.Maternal Behavior: The behavior patterns associated with or characteristic of a mother.Poverty Areas: City, urban, rural, or suburban areas which are characterized by severe economic deprivation and by accompanying physical and social decay.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.Australasia: Australia, New Zealand and neighboring islands in the South Pacific Ocean. (Random House Unabridged Dictionary, 2d ed.)Epidemiologic Methods: Research techniques that focus on study designs and data gathering methods in human and animal populations.AccidentsIsraelGeography: 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)Asphyxia: A pathological condition caused by lack of oxygen, manifested in impending or actual cessation of life.SwedenBangladeshVitamin A: Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of CAROTENOIDS found in plants. It is enriched in the liver, egg yolks, and the fat component of dairy products.Health 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.Spatial Analysis: Techniques which study entities using their topological, geometric, or geographic properties.IndiaMuscular Atrophy, Spinal: A group of disorders marked by progressive degeneration of motor neurons in the spinal cord resulting in weakness and muscular atrophy, usually without evidence of injury to the corticospinal tracts. Diseases in this category include Werdnig-Hoffmann disease and later onset SPINAL MUSCULAR ATROPHIES OF CHILDHOOD, most of which are hereditary. (Adams et al., Principles of Neurology, 6th ed, p1089)EuropeFamily Planning Services: Health care programs or services designed to assist individuals in the planning of family size. Various methods of CONTRACEPTION can be used to control the number and timing of childbirths.Unemployment: The state of not being engaged in a gainful occupation.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.New JerseyBirth Intervals: The lengths of intervals between births to women in the population.Twins: Two individuals derived from two FETUSES that were fertilized at or about the same time, developed in the UTERUS simultaneously, and born to the same mother. Twins are either monozygotic (TWINS, MONOZYGOTIC) or dizygotic (TWINS, DIZYGOTIC).Survival of Motor Neuron 1 Protein: A SMN complex protein that is essential for the function of the SMN protein complex. In humans the protein is encoded by a single gene found near the inversion telomere of a large inverted region of CHROMOSOME 5. Mutations in the gene coding for survival of motor neuron 1 protein may result in SPINAL MUSCULAR ATROPHIES OF CHILDHOOD.Economics: The science of utilization, distribution, and consumption of services and materials.Republic of BelarusMexicoDietary Supplements: Products in capsule, tablet or liquid form that provide dietary ingredients, and that are intended to be taken by mouth to increase the intake of nutrients. Dietary supplements can include macronutrients, such as proteins, carbohydrates, and fats; and/or MICRONUTRIENTS, such as VITAMINS; MINERALS; and PHYTOCHEMICALS.Smoking: Inhaling and exhaling the smoke of burning TOBACCO.Emigration and Immigration: The process of leaving one's country to establish residence in a foreign country.Malawi: A republic in southern Africa east of ZAMBIA and MOZAMBIQUE. Its capital is Lilongwe. It was formerly called Nyasaland.Child Health Services: Organized services to provide health care for children.WisconsinArab World: A historical and cultural entity dispersed across a wide geographical area under the administrative, intellectual, social, and cultural domination of the Arab empire. The Arab world, under the impetus of Islam, by the eighth century A.D., extended from Arabia in the Middle East to all of northern Africa, southern Spain, Sardinia, and Sicily. Close contact was maintained with Greek and Jewish culture. While the principal service of the Arabs to medicine was the preservation of Greek culture, the Arabs themselves were the originators of algebra, chemistry, geology, and many of the refinements of civilization. (From A. Castiglioni, A History of Medicine, 2d ed, p260; from F. H. Garrison, An Introduction to the History of Medicine, 4th ed, p126)Healthcare Disparities: Differences in access to or availability of medical facilities and services.History, 16th Century: Time period from 1501 through 1600 of the common era.World Health: The concept pertaining to the health status of inhabitants of the world.Marriage: The social institution involving legal and/or religious sanction whereby individuals are joined together.History, 20th Century: Time period from 1901 through 2000 of the common era.History, 17th Century: Time period from 1601 through 1700 of the common era.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.Predictive Value of Tests: In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.Appalachian Region: A geographical area of the United States with no definite boundaries but comprising northeastern Alabama, northwestern Georgia, northwestern South Carolina, western North Carolina, eastern Kentucky, eastern Tennessee, western Virginia, West Virginia, western Maryland, southwestern Pennsylvania, southern Ohio, and southern New York.Suriname: A republic in the north of South America, bordered on the west by GUYANA (British Guiana) and on the east by FRENCH GUIANA. Its capital is Paramaribo. It was formerly called Netherlands Guiana or Dutch Guiana or Surinam. Suriname was first settled by the English in 1651 but was ceded to the Dutch by treaty in 1667. It became an autonomous territory under the Dutch crown in 1954 and gained independence in 1975. The country was named for the Surinam River but the meaning of that name is uncertain. (From Webster's New Geographical Dictionary, 1988, p1167 & Room, Brewer's Dictionary of Names, 1992, p526)Crying: To utter an inarticulate, characteristic sound in order to communicate or express a feeling, or desire for attention.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.Parturition: The process of giving birth to one or more offspring.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)National Health Programs: Components of a national health care system which administer specific services, e.g., national health insurance.Health Status: The level of health of the individual, group, or population as subjectively assessed by the individual or by more objective measures.Hinduism: A complex body of social, cultural, and religious beliefs and practices evolved in and largely confined to the Indian subcontinent and marked by a caste system, an outlook tending to view all forms and theories as aspects of one eternal being and truth, and the practice of the way of works, the way of knowledge, or the way of devotion as a means of release from the round of rebirths. (From Webster, 3d ed)Sex Ratio: The number of males per 100 females.Air Pollutants: Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or material. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.Quintuplets: Five individuals derived from five FETUSES that were fertilized at or about the same time, developed in the UTERUS simultaneously, and born to the same mother.Live Birth: The event that a FETUS is born alive with heartbeats or RESPIRATION regardless of GESTATIONAL AGE. Such liveborn is called a newborn infant (INFANT, NEWBORN).Linear Models: Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.Obstetric Labor Complications: Medical problems associated with OBSTETRIC LABOR, such as BREECH PRESENTATION; PREMATURE OBSTETRIC LABOR; HEMORRHAGE; or others. These complications can affect the well-being of the mother, the FETUS, or both.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).History, 19th Century: Time period from 1801 through 1900 of the common era.