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Biomedical subjects

L J Waite

Publications and source records attributed to L J Waite.

At least 19 recordsLinked to original sources
PubMed1999

At risk on the cusp of old age: living arrangements and functional status among black, white and Hispanic adults.

OBJECTIVES: We examine the relationship between living arrangements and multiple measures of physical, cognitive, and emotional functioning in late midlife. METHODS: Using cross-sectional data from the Health and Retirement Study, we first assess the bivariate relationship between living arrangements and functioning; we then take into account demographic characteristics and measures of household resources and demands. RESULTS: We find evidence of differential functioning among individuals in various living arrangements. Married couples living alone or with children show the highest levels of functioning, whereas single adults living in complex households show the lowest levels. Functional deficits for those in complex households are reduced but not eliminated when we take demographic characteristics and household resources and demands into account. We find few differences by gender and race/ethnicity in the relationship between living arrangements and functioning. DISCUSSION: We show a pattern of poorer functioning among those in arguably the most demanding and least supportive household environments. This points to a vulnerable and risk-filled transition from middle to old age for these persons. Because Blacks and Hispanics show lower levels of functioning than Whites and are more likely to live in complex households, they may be particularly disadvantaged.

Activities of Daily Living↗
PubMed1999

Interrelated family-building behaviors: cohabitation, marriage, and nonmarital conception.

Data from the National Longitudinal Study of the High School Class of 1972 are used to estimate a series of models of entry into marriage, entry into cohabitation, and nonmarital pregnancy. Our models account explicitly for the endogeneity of one outcome as a predictor of another by taking into account both heterogeneity across individuals due to unmeasured factors that may affect all these outcomes and the correlation in the unmeasured factors across processes. We find that these heterogeneity components are strongly and positively related across the outcomes. Women who are more likely to cohabit, marry, or become pregnant while unmarried are also more likely to do each of the others. Although black and white women differ in the likelihood of these behaviors, the interrelations of the behaviors are quite similar across groups.

Adolescent↗
PubMed1997

Non-voltage-gated Ca2+ influx through mechanosensitive ion channels in aortic baroreceptor neurons.

The mechanisms underlying mechanotransduction in baroreceptor neurons (BRNs) are undefined. In this study, we specifically identified aortic baroreceptor neurons in primary neuronal cell cultures from nodose ganglia of rats. Aortic baroreceptor neurons were identified by labeling their soma with the fluorescent dye 1,1'-dioleyl-3,3,3',3'-tetramethylin-docarbocyanine (DiI) applied to the aortic arch. Using Ca2+ imaging with fura 2, we examined these BRNs for evidence of Ca2+ influx and determined its mechanosensitivity and voltage dependence. Mechanical stimuli were produced by ejecting buffer from a micropipette onto the cell surface with a pneumatic picopump, producing a shift in the center of mass of the cell that was related to intensity of stimulation. Ninety-three percent of DiI-labeled neurons responded to mechanical stimulation with an increase in [Ca2+]i. The magnitude of the increases in [Ca2+]i was directly related to the intensity of the stimulus and required the presence of external Ca2+. The trivalent cations Gd3+ or La3+ in equimolar concentrations (20 mumol/L) eliminated the K(+)-induced rises in [Ca2+]i, demonstrating that both trivalent cations are equally effective at blocking voltage-gated Ca2+ channels in these baroreceptor neurons. In contrast, the mechanically induced increases in [Ca2+]i were blocked by Gd3+ (20 mumol/L) only and not by La3+ (20 mumol/L). Stretch-activated channels (SACs) have been shown in other preparations to be blocked by Gd3+ specifically. Our data demonstrate that (1) BRNs, specifically identified as projecting to the aortic arch, have ion channels that are sensitive to mechanical stimuli; (2) mechanically induced Ca2+ influx in these cells is mediated by a Gd(3+)-sensitive ion channel and not by voltage-gated Ca2+ channels; (3) the magnitude of the Ca2+ influx is dependent on the intensity of the stimulus and the degree and duration of deformation; and (4) repeated stimuli of the same intensity result in comparable increases in [Ca2+]i. We conclude that mechanical stimulation increases Ca2+ influx into aortic BRNs independent of voltage-gated Ca2+ channels. The results suggest that Gd(3+)-sensitive SACs are the mechanoelectrical transducers in baroreceptors.

Animals↗
PubMed1995

Mechanical stimulation increases intracellular calcium concentration in nodose sensory neurons.

The cellular mechanisms involved in activation of mechanosensitive visceral sensory nerves are poorly understood. The major goal of this study was to determine the effect of mechanical stimulation on intracellular calcium concentration ([Ca2+]i) using nodose sensory neurons grown in culture. Primary cultures of nodose sensory neurons were prepared by enzymatic dispersion from nodose ganglia of 4-8 week old Sprague-Dawley rats. Whole cell [Ca2+]i was measured by a microscopic digital image analysis system in fura-2 loaded single neurons. Brief mechanical stimulation of individual nodose sensory neurons was achieved by deformation of the cell surface with a glass micropipette. In 31 of 50 neurons (62%), mechanical stimulation increased [Ca2+]i from 125 +/- 8 to 763 +/- 89 nM measured approximately 10 s after stimulation. [Ca2+]i then declined gradually, returning to near basal levels over a period of minutes. [Ca2+]i failed to increase after mechanical stimulation in the remaining 19 neurons. The mechanically-induced rise in [Ca2+]i was essentially abolished after the neurons were incubated for 5-10 min in zero Ca2+ buffer (n = 7) or after addition of gadolinium (10 microM), a blocker of stretch-activated ion channels (n = 5). The effect of gadolinium was reversed after removal of gadolinium. The results indicate that: (1) mechanical stretch increases [Ca2+]i in a subpopulation of nodose sensory neurons in culture, and (2) the stretch-induced increase in [Ca2+]i is dependent on influx of Ca2+ from extracellular fluid and is reversibly blocked by gadolinium. The findings suggest that opening of stretch-activated ion channels in response to mechanical deformation leads to an increase in Ca2+ concentration in visceral sensory neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Premarital cohabitation and subsequent marital dissolution: a matter of self-selection?

Married couples who began their relationship by cohabiting appear to face an increased risk of marital dissolution, which may be due to self-selection of more dissolution-prone individuals into cohabitation before marriage. This paper uses newly developed econometric methods to explicitly address the endogeneity of cohabitation before marriage in the hazard of marital disruption by allowing the unobserved heterogeneity components to be correlated across the decisions to cohabit and to end a marriage. These methods are applied to data from the National Longitudinal Study of the High School Class of 1972. We find significant heterogeneity in both cohabitation and marriage disruption, and discover evidence of self-selection into cohabitation.

Adult↗
PubMed1995

Does marriage matter?

Explore the source record for details and available documents.

Black or African American↗
PubMed1993

Are blacks more likely than whites to receive and provide social support in middle and old age? Yes, no, and maybe so.

Differences in the social support transactions of White and Black adults were investigated using data from the 1987/88 National Survey of Families and Households. Multivariate models were estimated to identify differences between Whites and Blacks in the likelihood that they provided and received instrumental and emotional support. Most importantly, we examined, separately for men and women, variations in Black-White differences from mid-life to old age. Results indicated that, overall, Blacks were no more likely than Whites to provide and receive both types of social support. In fact, Black women were less likely than White women to provide instrumental support to others. However, in old age, Black women were more likely to receive instrumental support and about as likely as White women to provide such support. These findings suggest that when comparing the informal support activities of White and Black adults, race needs to be considered in the context of gender and stage of life.

Black or African American↗
PubMed1993

A joint model of marital childbearing and marital disruption.

Married couples with children appear to be less likely to end their marriages than childless couples, especially when the children are young. Although this suggests that children affect the chances that their parents will divorce, the process may not be so simple: the chances that the marriage will last also may affect couples' willingness to make the commitment to the marriage implied by having children. This paper uses data from the Panel Study of Income Dynamics (PSID) to test the hypothesis that the risk of disruption faced by a married woman affects the chances that she will conceive and bear a child. The model used takes into account the simultaneous relationships between marital dissolution and marital fertility by including the hazard of disruption as a predictor of timing and likelihood of marital conception, and by including the results of previous fertility decisions as predictors of disruption of the marriage. We find that the hazard of disruption has strong negative effects on the hazard of marital childbearing, lengthening the intervals between births and decreasing the chances that a child will be born. This effect appears to be strongest for women who have had at least one child, either before or during the current marriage, although it is also large for childless women. Explicitly including the hazard of disruption in models of marital childbearing has sizable and important effects on many predictors of fertility.

Adolescent↗
PubMed1990

Microcomputer-based rehabilitation for unilateral left visual neglect: a randomized controlled trial.

Microcomputers are widely used in cognitive rehabilitation of brain damage. Unilateral neglect is commonly a target of cognitive rehabilitation, both computer-based and non-computer-based. This study reports the results of a randomized controlled trial of computer-based rehabilitation with blind follow-up for six months. Thirty-six patients with unilateral neglect, as defined by the behavioral subtests of the Behavioural Inattention Test, were randomized into two groups. One group of 20 subjects received a mean of 15.5 (SD = 1.8) hours of computerized scanning and attentional training; the second group of 16 subjects received a mean of 11.4 (SD = 5.2) hours of recreational computing (selected to minimize scanning and timed attentional tasks). Blind follow-up at the end of training and six months after revealed no statistically or clinically significant results between groups. These findings argue against routine clinical use of this type of computerized training until further studies establish what type, frequency, and duration of training produces clinically significant changes in unilateral visual neglect if, indeed, computerized training can have an effect with this type of disorder.

Aged↗
PubMed1988

Child care and children's illness.

This paper uses nationally representative data from the Child Health Supplement of the 1981 National Health Interview Survey to test the hypothesis that the larger the groups in which children receive care, the more days per year they spend in bed due to illness. We estimate a model of annual bed days for children ages six months to two and one-half years old, and separately for children two and one-half to five years old. Our results show significantly higher numbers of bed days for children in day care centers than for children at home for both age groups, controlling for confounding factors. Children in family day care have significantly more bed days than those at home, but only among the younger sample. The negative effect of family day care is less than that of child care centers. Although the relative effect of group care is to increase annual bed days by 30 to 19 per cent, the absolute effect is modest with children in group care having 1.3 to .6 more bed days per year.

Child Day Care Centers↗
PubMed1988

Child care for preschoolers: differences by child's age.

Because of the high rates of employment of mothers, a large and increasing number of preschool children receive regular care from someone else. This article develops and tests hypotheses about the choice of child care arrangements for younger and older preschool children, using data from the National Longitudinal Survey of Young Women. We argue that appropriate care depends on the age of the child. It includes care by the mother or a paid provider in the child's home for children aged 0-2 and mother care and nursery school or center care for those 3-5. We estimate models of the mother's employment and choice of child care separately for younger and older preschoolers. Our results show that need for care, presence of substitutes for the mother, financial resources, and preferences all affect both full-time care by the mother and the type of child care chosen by working women, although they affect these two decisions in different ways.

Adult↗
PubMed1984

Local labor markets, children and labor force participation of wives.

Most research on married women's labor force participation relates characteristics of individual women to their probability of labor force participation. Some studies relate characteristics of geographic areas to average labor force participation rates in those areas, although these aggregate level analyses are usually gross tests of ideas about individual-level processes. Here we take a quintessentially sociological perspective and seek to understand how characteristics of geographic areas structure the relationship between properties of individual women and their probabilities of labor force participation. Our analysis has two steps. In step one, we fit individual-level probit models of married women's probability of labor force participation. A separate model is fitted in each of 409 areas using 1970 Census data, and the relationship between individual characteristics and labor force participation is found to vary substantially across areas. In step two, we attempt to explain areal variation in the effects of women's children on their labor force participation. We hypothesize that the effect of children on their mothers' labor force participation is a function of the cost and availability of childcare , and of the "convenience" of jobs for working mothers in the places where the mothers live. Measures of childcare cost, childcare availability and job convenience are developed. Weighted least squares analyses of probit coefficients from the first stage are, in general, very consistent with our findings, and suggest that the approach taken in this paper is likely to be a fruitful one for future studies.

Adolescent↗
PubMed1981

U.S. women at work.

Women made up 43% of the U.S. labor force in 1980, up from 29% in 1950, and 52% of all women 16 and over were working or looking for work compared to 34% in 1950. The surge in women's employment is linked to more delayed marriage, divorce, and separation, women's increased education, lower fertility, rapid growth in clerical and service jobs, inflation, and changing attitudes toward "woman's place." Employment has risen fastest among married women, especially married mothers of children under 6, 45% of whom are now in the labor force. Some 44% of employed women now work fulltime the year round, but still average only $6 for every $10 earned by men working that amount. This is partly because most women remain segregated in low paying "women's jobs" with few chances for advancement. Among fulltime workers, women college graduates earn less than male high school dropouts. Working wives were still spending 6 times more time on housework than married men in 1975 and working mothers of preschool children are also hampered by a severe lack of daycare facilities. Children of working women, however, appear to develop normally. Equal employment opportunity and affirmative action measures have improved the climate for working women but not as much as for minorities. The federal income tax and social security systems still discriminate against 2 income families. Woman's position in the U.S. labor force should eventually improve with the inroads women are making in some male-dominated occupations and gains in job experience and seniority among younger women who now tend to stay in the labor force through the years of childbearing and early childrearing, unlike women in the 1950s and 1960s.

Age Factors↗
PubMed1981

Young women's transition to marriage.

This paper examines determinants of timing of marriage for young women by modeling the transition from the single to the married state by age. This approach, combined with a large longitudinal data set, allows us to disaggregate the analysis into fine age groupings and to include situational and attitudinal factors in our model. We find that those characteristics of a young woman's parental family that reflect the availability of parental resources tend to decrease the chances of a marriage during the early teens. Chances of marrying appear to decrease with increases in the availability and attractiveness of alternatives to the wife role and in the costs of assuming it. We discuss these results from the perspective of the societal and parental normative pressures which affect timing of marriage for young women.

Adolescent↗
PubMedDate not supplied

Teenagers willing to consider single parenthood: who is at greatest risk?

Data from the High School and Beyond panel study indicate that of 13,061 female high school sophomores who responded to both the baseline questionnaire in 1980 and a 1982 follow-up, 41 percent of blacks, 29 percent of Hispanics and 23 percent of non-Hispanic whites said they either would or might consider having a child outside of marriage. Such willingness was higher among young women who, according to their background characteristics, were at greater risk of teenage parenthood. In addition, young black women were more willing to consider having a child while single than were white or Hispanic respondents, at every level of risk. The data also show that, with the possible exception of Hispanics, willing respondents generally registered much higher rates of nonmarital childbearing over the two years following the baseline survey than the young women unwilling to consider nonmarital childbearing. Respondents' reports on their own disciplinary problems in school and on their class-cutting and absenteeism showed that such problem behavior was related to the teenagers' willingness to consider nonmarital childbearing: Proportionally more of the respondents who ranked high on a scale of problem behavior were willing to do so, even when background differences were controlled for. In addition, when the respondents' educational expectations were used as proxy measures of the potential opportunity costs of single parenthood, the results revealed that the higher their educational expectations, the lower their willingness to have an out-of-wedlock birth.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗