Results of a Search for Sub-GeV Dark Matter Using 2013 LUX Data

The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5  GeV/c^{2} using 1.4×10^{4}  kg day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.

First Searches for Axions and Axionlike Particles with the LUX Experiment

The first searches for axions and axionlike particles with the Large Underground Xenon experiment are presented. Under the assumption of an axioelectric interaction in xenon, the coupling constant between axions and electrons g_{Ae} is tested using data collected in 2013 with an exposure totaling 95 live days ×118  kg. A double-sided, profile likelihood ratio statistic test excludes g_{Ae} larger than 3.5×10^{-12} (90% C.L.) for solar axions. Assuming the Dine-Fischler-Srednicki-Zhitnitsky theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12  eV/c^{2}, while for the Kim-Shifman-Vainshtein-Zhakharov description masses above 36.6  eV/c^{2} are excluded. For galactic axionlike particles, values of g_{Ae} larger than 4.2×10^{-13} are excluded for particle masses in the range 1-16  keV/c^{2}. These are the most stringent constraints to date for these interactions.

Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5  kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41}  cm^{2} (σ_{p}=5×10^{-40}  cm^{2}) at 35  GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Results from a Search for Dark Matter in the Complete LUX Exposure

We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×10^{4}  kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50  GeV c^{-2}, WIMP-nucleon spin-independent cross sections above 2.2×10^{-46}  cm^{2} are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1×10^{-46}  cm^{2} at 50  GeV c^{-2}.

Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment

We present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4×10^{4}  kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=9.4×10^{-41}  cm^{2} (σ_{p}=2.9×10^{-39}  cm^{2}) at 33  GeV/c^{2}. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Improved Limits on Scattering of Weakly Interacting Massive Particles from Reanalysis of 2013 LUX Data

We present constraints on weakly interacting massive particles (WIMP)-nucleus scattering from the 2013 data of the Large Underground Xenon dark matter experiment, including 1.4×10^{4}  kg day of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength, improved event-reconstruction algorithms, a revised background model including events originating on the detector walls in an enlarged fiducial volume, and new calibrations from decays of an injected tritium β source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4  GeV c^{-2}, these new results give the most stringent direct limits on the spin-independent WIMP-nucleon cross section. The 90% C.L. upper limit has a minimum of 0.6 zb at 33  GeV c^{-2} WIMP mass.

Planning for motherhood: fertility attitudes, desires and intentions among women with disabilities

CONTEXT

An estimated 10% of U.S. women of reproductive age report a current disability; however, the relationship between disability, motherhood attitudes and fertility intentions among these women is largely unknown.

METHODS

Data from the 2006-2010 National Survey of Family Growth were used to examine attitudes toward motherhood and fertility intentions among 10,782 U.S. women aged 15-44. A series of regression models assessed, separately for mothers and childless women, associations between disability status and women's attitudes and intentions.

RESULTS

Women with and without disabilities held similar attitudes toward motherhood. Among women without children, women with and without disabilities were equally likely to want a child and equally likely to intend to have one. However, childless women with disabilities who wanted and intended to have a child were more likely to report uncertainty about those intentions than were childless women without disabilities (odds ratio, 1.7). Mothers with disabilities were more likely to want another child (1.5), but less likely to intend to have a child (0.5), than were mothers without disabilities.

CONCLUSIONS

Deepening understanding of the reproductive health desires, needs and challenges of women with disabilities is essential if the highest quality reproductive health services are to be provided for all.

Delinquency Among Adolescents with Disabilities

This study expands upon previous research by utilizing nationally representative data and multivariate analyses to examine the relationship between an adolescent's disability status and their likelihood of engaging in a spectrum of delinquent behaviors through age 16. Logistic regression models of 7,232 adolescents from the National Longitudinal Survey of Youth 1997 are used to investigate the association between the presence of a learning disability or emotional condition, chronic health condition, sensory condition, physical disability, or multiple conditions and ten delinquent acts, including violence-related delinquency, property crimes, drug offenses, and arrest. Additional analyses explore differences in delinquency prevalence by more specific types of limiting conditions. Results indicate that adolescents with learning disabilities or emotional conditions are particularly at risk of committing delinquent acts. Findings suggest that disability status is important to consider when examining adolescent delinquency; however, not all youth with disabilities have equal experiences.

Child and adult disability in the 2000 Census: disability is a household affair

BACKGROUND

Survey data indicate that individuals with disabilities in the United States often experience less advantageous economic and social resources than individuals without disabilities. Furthermore, they often reside with other individuals with disabilities in the same household. However, less is known about resource availability when multiple child and adult household members have a disability.

OBJECTIVE

We use child-level data from the 2000 Census to examine the relationship between aggregation of disability in households with children and education, labor force participation, poverty level, and inadequate housing.

METHODS

We utilize tabular analysis and Kruskal-Wallis tests to examine how resources in education, employment, income, and housing adequacy compare for children with disabilities who are the only member of their household with a disability, children with disabilities who live in a household with at least one other member with a disability, children without disabilities who live in a household where no other member has a disability, and children without disabilities who live in a household where at least one other member has a disability.

RESULTS

Among children without a disability, 86% live in a household in which no other member has a disability. Among children with a disability, 53% live in a household in which no other adult or child has a disability. Poverty, inadequate housing, and low adult education were more than two times more likely - and adult unemployment over five times more likely - in households with multiple members with disability versus households without disability.

CONCLUSION

There is a high prevalence of aggregation of adults and children with disability in households of children with disability. These households have substantially fewer resources than households who do not have children or adults with disabilities.

The Educational Attainment Process Among Adolescents with Disabilities And Children of Parents with Disabilities

This article uses data from the National Longitudinal Survey of Youth 1997 (NLSY97) to examine the relationship between disability, parental and youth university expectations in 1997, and youth high school completion and university enrolment by 2003. Results indicate that educational attainment is not equal for young adults with and without disabilities in the United States. Parents-but not adolescents-are likely to reduce their educational expectations when adolescents have a mild or serious disability, net of school performance. These parental-but not adolescent-expectations are significantly associated with high school completion. Finally, even after controlling for educational expectations and school performance, youth with serious disabilities are much less likely to graduate from high school than youth without disabilities. Despite the considerable strides made in the implementation of the Individuals with Disabilities Education Act, students with disabilities are not achieving educational parity in graded schooling.

PARENTING A CHILD WITH A DISABILITY: AN EXAMINATION OF RESIDENT AND NON-RESIDENT FATHERS

Children with disabilities often require more extensive family involvement and greater paternal support than other children. Yet these children are the children least likely to live with their fathers. This paper uses data from the National Longitudinal Survey of Youth 1997 from the United States to examine the association between child disability and resident and non-resident biological fathers' supportiveness, relationship, and monitoring of their children. Regression analyses indicate significant challenges for all fathers of children with disabilities. Children of resident fathers report more positive interactions than children of non-resident fathers. However, earlier co-residence and more frequent contact significantly improve the quality of father-youth relationships among men who do not live with their children.

School-to-work program participation and the post-high school employment of young adults with disabilities

Previous research on the education-to-employment transition for students with disabilities has suggested that participation in school-to-work programs is positively associated with post-high school success. This article utilizes data from the National Longitudinal Survey of Youth 1997 (NLSY97) to extend these findings in several ways. First, we assess the efficacy of specific types of school-based and work-based initiatives, including job shadowing, mentoring, cooperative education, school-sponsored enterprise, technical preparation, internships, and career major. Next, we extend the usual focus on the employment outcomes of work status and financial compensation to consider job-specific information on the receipt of fringe benefits. Overall, results from longitudinal multivariate analyses suggest that transition initiatives are effective in facilitating vocational success for this population; however, different aspects of school-to-work programs are beneficial for different aspects of employment. School-based programs are positively associated with stable employment and full-time work while work-based programs most consistently increase the likelihood that youth with disabilities will be employed in jobs that provide fringe benefits. Analyses also indicate that - once individuals with disabilities are stably employed - they can be employed in "good" jobs that provide employee benefits.

Distressed neighborhoods and child disability rates: analyses of 157,000 school-age children

The aim of this study was to assess rates of childhood disability as indicated by functional limitation of motor, sensory, or self-care skills in children living in severely-distressed neighborhoods. For a neighborhood in the US Census Track to be considered severely distressed, three of the following four characteristics need to be present: >27% of children live in poverty, >23% high school drop-out rate, >34% male unemployment rate, and >37% of households headed by females alone. In the 2000 US Census, 157 000 children between ages 5 and 15 years resided in the State of Rhode Island. Severely-distressed neighborhoods were found in 12.6% of Rhode Island Census Tracks. These areas accounted for 14.5% of the school-age population, 25% of children with motor disabilities, 29% of children with self-care disabilities, and 14% of children with sensory disabilities. For each increasing level of neighborhood distress, rates of child disability increased. Child disability rates in moderately distressed neighborhoods were 3.7%, compared with 1.1% in advantaged neighborhoods. Children in distressed neighborhoods had disproportionately high rates of disability, especially in motor and self-care functioning. Comprehensive interventions aimed at children in distressed neighborhoods are crucial to reduce health disparities for vulnerable children.

Family developmental risk factors among adolescents with disabilities and children of parents with disabilities

This paper investigates how the learning environments and family dynamics differ if households have a child with a disability or a parent with a disability. Using data from the National Longitudinal Survey of Youth 1997, results indicate that children with disabilities experience similar learning environments as other children, but have somewhat weaker relationships with their parents. In two-parent families, maternal disability lowers parents' school involvement and is associated with a less enriching home environment. Paternal disability reduces maternal monitoring and positive family activities possibly because mothers divert care-giving resources from their children to their male partners. Children in mother-headed households experience learning environments and family dynamics that are similar regardless of their own disability status or that of their mothers, but these outcomes are markedly inferior to those of children growing up in two-parent households. Future research on adolescent development should consider the disability status of children and parents, with particular attention to patterns of gendered care-giving in American families.

Social Identity and Community Effects on Contraceptive Use and Intentions in Southern Ethiopia

In this study, data gathered in southern Ethiopia are used to explain how ethnic and religious identities affect current or intended contraceptive use. The only compositionalfactors that increase the likelihood of birth limitation are having a member of the family with a higher level of education and community access to health services. Compositional factors by themselves do not explain Muslim and ethnic variations in contraceptive use and intentions. Village health and economic crises do not promote birth limitation. One normative economic factor--the practice of sons' inheritance of land from their fathers--considerably reduces the likelihood of contraceptive use, but does not account for religious and ethnic differentials. No evidence is found of a minority-status effect on contraception. Exposure to ethnic and religious diversity in the community of residence substantially increases the likelihood of emergent birth limitation, especially among the predominant Muslim Silte population.

Child disability and mothers' tubal sterilization

CONTEXT

The needs of children with disability can be substantial, leading some parents to consider contraceptive sterilization to prevent additional births.

METHODS

Matched records from the 1993 National Health Interview Survey and the 1995 National Survey of Family Growth were used to investigate the relationship between child disability and mothers' sterilization. Data included the birth records of 8,711 children, information on older children in the household, and the mothers' background and reproductive characteristics. Logistic and Cox regression models were used to estimate the effect of the birth of a child with a disability on the risk of mothers' sterilization.

RESULTS

The birth of a child with disability has no effect on the likelihood that a mother will undergo sterilization within the next month; however, women who have an older child with severe disability are more likely than those whose older children are nondisabled to undergo sterilization within a month after the birth of another child (odds ratio, 2.6). Severe disability in a newborn significantly increases the risk of sterilization 1-36 months after birth (risk ratio, 1.7); severe disability among older children also appears to increase the risk of sterilization 1-36 months after birth (1.5), although this result was only marginally significant.

CONCLUSIONS

Women often respond to the birth of children with disabilities by changing their fertility plans, although usually not immediately unless they have older children with severe disability. These findings are consistent with parents'desire to have a nondisabled child and with their need to care for an exceptional child by forgoing additional births.

Functional disability and school activity limitations in 41,300 school-age children: relationship to medical impairments

OBJECTIVE

Our purpose was to examine the contribution of medical impairments to functional disability and school activity limitations in 41,300 school-age children participating in the 1994-1995 National Health Interview Survey.

METHODS

The 1994 and 1995 National Health Interview Survey and Disability Interview Supplement samples provide International Classification of Diseases, Ninth Revision medical impairment codes for children with functional limitations or school activity limitations in a nationally representative US sample. Functional limitations were distributed as follows: mobility 12.4/1000 (95% confidence interval [CI]: 11.1-13.6), self-care 8.8/1000 (95% CI: 7.7-9.8), communication 52.9/1000 (95% CI: 50.2-55.5), and learning 104.6/1000 (95% CI: 100.7-108.4). Functional disability status was classified as 4.1% mild, 5.9% major, and 1.9% multiple. School activity limitations included 4.1% needing or receiving special education, 0.7% unable to attend, and 0.9% limited attendance. We categorized International Classification of Diseases, Ninth Revision impairment codes reported in conjunction with medical usage as physical disorders (n = 1251; eg, leukemia, diabetes), asthma (n = 916), neurodevelopmental disorders (n = 802; eg, cerebral palsy, epilepsy, mental retardation, autism, blindness, deafness), and learning-behavior disorders (n = 806; eg, attention-deficit/hyperactivity disorder, learning disability, anxiety) for children with functional or school activity limitations. Of children with multiple functional disabilities, 29.9% had neurodevelopmental disorders, 27.1% had learning-behavior disorders, 18.1% had physical disorders, 4.2% had asthma, and 20.8% did not have an identified medical impairment because they had not received medical services in the past year. Among children requiring special education, physical disorders accounted for 9.4%, neurodevelopmental disorders for 16.7%, learning and behavior disorders for 17%, asthma for 3.4%, and 53.4% did not have an identified medical impairment because they had not received medical services in the past year.

CONCLUSIONS

Chronic health impairments, neurodevelopmental disorders, learning-behavior disorders, and functional limitations in essential activities are required to understand the complexity of disability in school-age children. A large number of children with functional disability or school activity limitations have not received ongoing medical services.

The proximate determinants of the decline to below-replacement fertility in Addis Ababa, Ethiopia

Between 1990 and 2000, the total fertility rate (TFR) in Ethiopia declined moderately from 6.4 to 5.9 children per woman of reproductive age. During the same period, the TFR in the capital city of Addis Ababa declined from 3.1 to 1.9 children per woman. Even more striking than the magnitude of this decline is that it occurred in the absence of a strong and effective national family planning program. In this study, the components of this fertility decline are identified using the Bongaarts framework of the proximate determinants of fertility. The results of a decomposition analysis indicate that a decrease in the age-specific proportions of women who are married, followed by an increase in contraceptive use are the most important mechanisms by which fertility has declined in Addis Ababa. Poor employment prospects and relatively high housing costs are likely factors that encourage couples to delay marriage and reduce marital fertility.

War, famine and excess child mortality in Africa: the role of parental education

BACKGROUND

Civilian-targeted warfare and famine constitute two of the greatest public health challenges of our time. Both have devastated many countries in Africa. Social services, and in particular, health services, have been destroyed. Dictatorial and military governments have used the withholding of food as a political weapon to exacerbate human suffering. Under such circumstances, war and famine are expected to have catastrophic impacts on child survival. This study examines the role of parental education in reducing excess child mortality in Africa by considering Tigrai-Ethiopia, which was severely affected by famine and civil war during 1973--1991.

METHODS

This study uses data from the 1994 Housing and Population Census of Ethiopia and on communities' vulnerability to food crises. Child mortality levels and trends by various subgroups are estimated using indirect methods of mortality estimation techniques. A Poisson regression model is used to examine the relationship between number of children dead and parental education.

RESULTS

Although child mortality is excessively high (about 200 deaths per 1000 births), our results show enormous variations in child mortality by parental education. Child mortality is highest among children born to illiterate mothers and illiterate fathers. Our results also show that the role of parental education in reducing child mortality is great during famine periods. In the communities devastated by war, however, its impact was significant only when the father has above primary education. CONCLUSIONS Our findings suggest that both mother's and father's education are significantly and negatively associated with child mortality, although this effect diminishes over time if the crisis is severe and prolonged. The policy implications of our study include, obviously, reducing armed conflict, addressing food security in a timely manner, and expansion of educational opportunities.

Functional limitations and key indicators of well-being in children with disability

OBJECTIVES

To compare measures of well-being in children with and without different types and severity of limitations.

DESIGN

Nationally representative data for American children aged 5 to 17 years were drawn from the 1994 and 1995 National Health Interview Surveys on Disability (NHIS-D) (N = 41,300) and the Year 2000 Health Supplement to the 1994 NHIS-D (N = 9530). Family resources, safety, health status, and health access were measures of environment. The presence and severity of limitations were measured in the domains of mobility, self-care, communication, and learning.

RESULTS

Children with functional limitations were more likely to live in families with limited resources and have greater exposure to secondhand smoke, less access to health care, and lower health status. Children with a limitation were not less likely to have a regular source of medical care, but they more often were delayed or prevented from getting necessary health care due to cost or insurance.

CONCLUSIONS

Standard measures of child well-being were appropriate for children with functional limitations and showed their unfavorable situations. Children with functional limitations more often have unfavorable family resources, less healthy home environments, poorer health status, and less health service access than other children, making them more susceptible to developmental difficulties beyond those difficulties associated with the challenges of their specific functional limitations.

Sexual and fertility behaviors of American females aged 15-19 years: 1985, 1990, and 1995

OBJECTIVES

This study characterized changes in sexual and reproductive behaviors from 1985 through 1995 among American females aged 15 to 19 years and related these changes to family factors.

METHODS

Nationally representative sample survey data from the 1995 National Survey of Family Growth were analyzed with Weibull hazards models of age at first intercourse and first pregnancy and with logistic regression models of contraceptive use at first intercourse and pregnancy outcome.

RESULTS

Improvements in the family socioeconomic situations of young women have lessened the risk of teen motherhood, while changes in family structure have increased the risk. Young women whose parents have more than a high school education, who live with both parents, and who attend church delay the timing of first sexual intercourse and are more likely to use a contraceptive.

CONCLUSIONS

The trend of increases in teenage motherhood has ended owing to a halt in increases in the proportion of sexually active young women and substantial improvement in contraception, with the greatest improvements among those from advantageous family situations.

Family factors and social support in the developmental outcomes of very low-birth weight children

This study used data that were representative of the normative population of all infants born in 1988 and were followed during the first 3 years of life. Large developmental delays and limitations in function were common among children weighing less than 1500 g at birth. Among very low-birth weight infants, minority status and living in a household headed by a single mother further worsen the disadvantages associated with a very low birth weight. Nor could the disadvantages associated with very low birth weight be accounted for by controls for other risk factors or buffering statuses and behaviors. Among all children (including those of very low birth weight) poverty, reliance on Medicaid and other government sources for health insurance, a history of risky behaviors, and inadequate prenatal care are the major risk factors for developmental delays, limitations in function, and impairment at birth. State program benefit levels have no obvious effects on child outcomes, taking into account participation in individual programs. An important finding in light of TANF is that maternal work, the use of child care, and the form and cost of child care did not influence developmental delay, limitation in function, or impairment, the outcomes that we were able to measure during the first 3 years of life. TANF eligibility requirements, however, may increase difficulty in obtaining prenatal and other medical services for mothers and children in need--factors shown here to be related strongly to increased risk of low birth weight and developmental delays, limitations, and impairments. Race and ethnicity, poverty status, and family structure are fundamental factors in early child development and function. Minority status, poverty, and single-parent households greatly increase the likelihood that a mother will engage in risky behaviors (smoking, alcohol use, illegal drug use) during pregnancy and receive inadequate prenatal care. Risky behaviors and inadequate prenatal care are the major risk factors for a baby of very low birth weight. When perinatologists first encounter a new patient who is of very low birth weight they often see an infant who is minority, in poverty, and in a single-parent household. Although such children did more poorly in development and function by age 3, the major effects of these variables were through the selectivity of such children into very low birth weight; the direct impact of these factors on development is somewhat muted. This research suggests there are a number of policies that can reduce development delays and functional limitations among children in the United States. Programs that are targeted to a mother and child (such as WIC, AFDC, health insurance coverage, and possibly the more recent TANF programs) significantly reduced the risk an infant will be of very low birth weight. Access and use of adequate prenatal care are essential. Programs designed to combat maternal behaviors that place the fetus at risk (smoking, alcohol, and illegal drug use) can be very successful in reducing the likelihood an infant will be of very low birth weight. An additional payoff from such programs comes after the birth, because even taking into account birth weight, these variables negatively impact on early childhood development and function. Single-parent family structure, race and ethnic minority status, and poverty status also are known to impact on kindergarten readiness, so that we expect a delayed impact of these variables on the child. The strength of this article is the use of normative population data to assess the role of birth weight in child outcome. We examined prenatal risk factors for a baby of very low birth weight, traced the manner by which these selective risks are reflected in the composition of very low-birth weight babies, demonstrated how a very low birth weight was fundamental to delays in development, and identified risk factors and potential buffers in this process. (ABSTRACT TRUNCATED)

Household organization, women's autonomy, and contraceptive behavior in southern Ethiopia

The Southern Nations, Nationalities, and People's Region of Ethiopia (SNNPR) is home to 11 million people constituting more than 45 language and ethnic groups, most of whom live in extremely poor rural communities. Data for currently married, fecund women aged 15-49 from demographic surveys conducted in the SNNPR in 1990 and 1997 are used to investigate contraceptive knowledge and communication, and the use and future need for family planning services in this population. This study focuses on how these processes are affected by household organization and women's status, and on their implications for population policies and programs. Considerations of the implications of these results for understanding the fertility transition of a highly diverse African population under severe stress are presented. Although household extension and polygamy characterize one-third of the women sampled, they do not affect the women's contraceptive behavior. Women's literacy and autonomy are, by far, the most significant forces in the movement toward lower fertility in the region.

Improved disability population estimates of functional limitation among American children aged 5-17

OBJECTIVES

This paper (a) creates and validates measures for population survey data to assess functional limitation in mobility, self-care, communication, and learning ability for school-age American children; (b) calculates rates of functional limitation using these measures, and provides population estimates of the number of children with limitations; and (c) examines these limitations as a function of socioeconomic factors.

METHOD

The study is based on data for children aged 5-17 collected in the 1994 National Health Interview Survey on Disability. Ordinal values are assigned to survey items in the four functional areas and analyzed to produce scales of high reliability. These measures are used to identify within a 95% confidence interval the number of children with these limitations. Ordered logistic regression models measure the effects of functional limitations on disability and societal limitation. Socioeconomic differences are measured with an ordered logistic regression model that predicts severity and comorbidity.

RESULTS

Limitations in learning ability (10.6%) and communication (5.5%) are the most common, with mobility (1.3%) and self-care (0.9%) occurring less often. Six percent of children have one serious functional limitation and 2.0% have two or more serious functional limitations. This corresponds to 4.0 million school-age American children with serious functional limitations. Functional limitation is strongly linked to socioeconomic disadvantage and to residence in single-mother households.

CONCLUSIONS

Future population research should use multiple-item scales for four distinct areas of functional limitation, and a summary that takes into account both severity and comorbidity. The improved estimates of the number of school-age children with functional limitation in this paper may help contribute to a more informed scientific and policy discussion of functional limitation and disability among American school-age children. Future research on the disability process among children must consider the role of socioeconomic disadvantage and family structure.

Living arrangements of minority elders

We used 1990 census data to examine differences in the current living arrangements of minority elderly. We found that differences among the minority populations in age, sex, and marital status account for only a small part of the observed differences in living arrangements. However, while minority groups as a whole differ substantially from the White population, national ethnic patterns within groups appear to be relatively small. Hispanic ethnic groups vary little once differences in marriage patterns are taken into account, although differences are greater within the Asian population.

Women's status and infant mortality in rural Colombia

This paper investigates the effects of maternal demographic characteristics and social and economic statuses on infant mortality in rural Colombia. Demographic characteristics include the age of the mother, parity and length of preceding interbirth interval, and sex of infant. Measures of women's status at the time of birth include education, wage labor and occupation, economic stratum, place of residence, and whether the mother is living with a husband. The life history data for the study (involving 4,928 births) were collected in 1986 from a representative sample of two cohorts of women resident in rural central Colombia. Overall differentials in infant mortality by measures of women's status are small and are in good part associated with the differing reproductive behaviors of the women and variations in breastfeeding practices. The sharp declines in infant mortality recorded in rural Colombia in recent years appear less related to improved status of women than to reductions in fertility that enhance infant survivorship and to public health interventions shared by all segments of the population.

Demographic transitions and the life course: lessons from Japanese and American comparisons

Three features of early life course of Americans and Europeans during the twentieth century are of note: (1) the increased age-grading of transitions; (2) the closer spacing of different transitions, and (3) the more extensive overlap between economic and family transitions. Historical changes in the structure of individual life histories have been interpreted alternatively, as a consequence of industrialization and urbanization, or as the result of rising levels of the family and personal incomes available for consumption and investment in human capital skills. In this article we bring additional evidence to bear on this debate by comparing historical changes in the early life transitions of men and women in Japan and the United States. Trends in the transition to adulthood systematically relate to the structure of schools and labor markets in the two nations, drawing attention to the various life course implications of the institutional forms under which industrial societies may organize.

Migration Patterns During Italian Urbanization, 1865-1921

This study examines patterns of male migration in central Italy during its transformation from an agrarian to an urban-industrial society. The Italian population registers provide data on the extent and type of emigration among more than 3,500 men (ages 10 and over) who immigrated to the commune of Casalecchio di Reno, bordering the city of Bologna, from 1865 to 1915. Demographic and social differentials in overall rates of emigration and their relation to places of origin and destination are measured. The implications of these results for an understanding of population mobility are discussed.

Migration patterns during Italian urbanization, 1865-1921

This study examines patterns of male migration in central Italy during its transformation from an agrarian to an urban-industrial society. The Italian population registers provide data on the extent and type of emigration among more than 3,500 men (ages 10 and over) who immigrated to the commune of Casalecchio di Reno, bordering the city of Bologna, from 1865 to 1915. Demographic and social differentials in overall rates of emigration and their relation to places of origin and destination are measured. The implications of these results for an understanding of population mobility are discussed.

Social and environmental factors influencing contraceptive use among black adolescents

In 1979 survey among sexually active unmarried black adolescents from Chicago found that 28 percent of the young women and 18 percent of the young men used a contraceptive at first intercourse. Statistically significant differences in such contraceptive use among teenage women were found for three social and environmental characteristics: social class, parents' marital status and neighborhood quality. Thus, 41 percent of the young women from the highest social class used contraceptives at first intercourse, but only 17 percent of those from the lowest class did so. The proportions were 35 percent for young women from neighborhoods of high socioeconomic status and 17 percent for those from ghetto neighborhoods. Thirty-six percent of teenage women whose parents had intact marriages as of the adolescent's 11th birthday used contraceptives at first intercourse, compared with 23 percent of those from single-parent and divorced families. Among males, social class was the only one of these three characteristics that was statistically significant; 32 percent of adolescents from the highest class and 11 percent from the lowest practiced contraception at first intercourse. For teenagers of both sexes, career aspirations were of marginal statistical significance in the practice of contraception. Thirty-six percent of young women with high aspirations used contraceptives at first intercourse and 19 percent of those with low aspirations did so. Only four percent of the young men with low career aspirations used contraceptives, compared with 25 percent of those with high aspirations. Number of siblings, parental supervision of dating and having a sister who had become a teenage mother showed no association with contraceptive use.(ABSTRACT TRUNCATED AT 250 WORDS)

The impact of class, education, and health care on infant mortality in a developing society: The case of rural Thailand

Demographic and social factors affecting infant mortality in rural northern Thailand are examined using log-linear modifiedmultiple regression models and data drawn from a representative sample of married couples in Chiang Mai and Chiang Rai provinces. Demographic factors do not account for the effects of variations in parental ability or willingness to provide adequate infant care. The final model estimated incorporated both these social dimensions of child care. Parental ability, measured by father’s social class, mother’s health information, and local community development levels, continued to have significant independent effects upon infant survival. Parental willingness, measured by parent’s beliefs about intergenerational wealth transfers, no longer had a significant effect net of other social variables, but infant survival was still affected by whether both parents wanted a birth.

The impact of class, education, and health care on infant mortality in a developing society: the case of rural Thailand

Demographic and social factors affecting infant mortality in rural northern Thailand are examined using log-linear modified multiple regression models and data drawn from a representative sample of married couples in Chiang Mai and Chiang Rai provinces. Demographic factors do not account for the effects of variations in parental ability or willingness to provide adequate infant care. The final model estimated incorporated both these social dimensions of child care. Parental ability, measured by father's social class, mother's health information, and local community development levels, continued to have significant independent effects upon infant survival. Parental willingness, measured by parent's beliefs about intergenerational wealth transfers, no longer had a significant effect net of other social variables, but infant survival was still affected by whether both parents wanted a birth.

Community availability of contraceptives and family limitation

This study examines the impact of contraceptive service availability on contraceptive use in Korea, Mexico, and Bangladesh. Using World Fertility Survey Data on once-married females and their communities of residence, the multivariate analysis finds that the community level of contraceptive availability directly affects the likelihood of current use, net of the effects of community development, education, parity, and marital duration. The results are supportive of the recent policy emphasis on maximizing the geographic availability of contraceptive services.

Antecedents to contraceptive innovation: evidence from rural Northern Thailand

A number of different causal mechanisms have been proposed to explain the onset of fertility declines in populations with previously uncontrolled fertility, but they have never been adequately tested. The present study identifies and tests five antecedents to family limitation practices in a sample of 755 currently married couples resident in rural Northern Thailand. The log-linear multiple regression models estimated indicate that couples in more developed districts, more modern couples, couples in which wives have more equal roles, couples believing that intergenerational wealth transfers favor children rather than their parents, and more wealthy couples, were all significantly more likely to be early adopters of contraception. Local development levels appeared to have the greatest net effects on the timing of adoption of fertility control. In addition, couples in areas where contraceptive services were more readily available were also significantly more likely to be contraceptive innovators, net of these five variables.

Antecedents to Contraceptive Innovation: Evidence from Rural Northern Thailand

A number of different causal mechanisms have been proposed to explain the onset of fertility declines in populations with previously uncontrolled fertility, but they have never been adequately tested. The present study identifies and tests five antecedents to family limitation practices in a sample of 755 currently married couples resident in rural Northern Thailand. The loglinear multiple regression models estimated indicate that couples in more developed districts, more modern couples, couples in which wives have more equal roles, couples believing that intergenerational wealth transfers favor children rather than their parents, and more wealthy couples, were all significantly more likely to be early adopters of contraception. Local development levels appeared to have the greatest net effects on the timing of adoption of fertility control. In addition, couples in areas where contraceptive services were more readily available were also significantly more likely to be contraceptive innovators, net of these five variables.

Community Availability of Contraceptives and Family Limitation

This study examines the impact of contraceptive service availability on contraceptive use in Korea, Mexico, and Bangladesh. Using World Fertility Survey Data on once-married females and their communities of residence, the mutivariate analysis finds that the community level of contraceptive availability directly affects the likelihood of current use, net of the effects of community development, education, parity, and marital duration. The results are supportive of the recent policy emphasis on maximizing the geographic availability of contraceptive services.