Interparental conflict and adolescent depressed mood: the role of family functioning.

Family functioning was investigated as a mediator between interparental conflict and adolescent depressed mood among adolescents living in two-parent and divorced families. Data were collected three times, with one year intervals. At the initial interview, adolescents were, on the average, 15.5 years old. Two types of interparental conflict were assessed: interparental conflict involving arguments about the adolescent, and arguments focused on the parents' behaviors. The results confirmed that family functioning mediated the effects of parent issue/interparental conflict, but not adolescent issue/interparental conflict. This was most evident for girls than boys. Implications of the findings for research and practice are discussed.

Computational and experimental investigation of flow and fluid mixing in the roller bottle bioreactor.

The fully three-dimensional velocity field in a roller bottle bioreactor is simulated for two systems (creeping flow and inertial flow conditions) using a control volume-finite element method, and validated experimentally using particle imaging velocimetry. The velocity fields and flow patterns are described in detail using velocity contour plots and tracer particle pathline computations. Bulk fluid mixing in the roller bottle is then examined using a computational fluid tracer program and flow visualization experiments. It is shown that the velocity fields and flow patterns are substantially different for each of these flow cases. For creeping flow conditions the flow streamlines consist of symmetric, closed three-dimensional loops; and for inertial flow conditions, streamlines consist of asymmetric toroidal surfaces. Fluid tracers remain trapped on these streamlines and are unable to contact other regions of the flow domain. As a result, fluid mixing is greatly hindered, especially in the axial direction. The lack of efficient axial mixing is verified computationally and experimentally. Such mixing limitations, however, are readily overcome by introducing a small-amplitude vertical rocking motion that disrupts both symmetry and recirculation, leading to much faster and complete axial mixing. The frequency of such motion is shown to have a significant effect on mixing rate, which is a critical parameter in the overall performance of roller bottles.

Computational and experimental investigation of flow and particle settling in a roller bottle bioreactor.

It is shown that cell settling is a key factor affecting the performance of roller bottle bioreactors. The two-dimensional cross-sectional flow at the center of a roller bottle is simulated using a finite difference method, and the settling behavior of cells is simulated using particle dynamics algorithms and validated experimentally using fluorescent particles. The settling behavior of particles in the roller bottle flow is studied using both steady and time dependent rotation rates. Under steady flow conditions the flow is divided into two regions: one where the particles settle to the wall and one where the particles remain suspended indefinitely. The relative size of these two regions depends on the ratio of the settling velocity to the rotation rate of the bottle. For unsteady flows generated by periodic changes of the bottle rotation direction, the settling of cells is accelerated significantly, leading to complete deposition in just a few turns of the bottle.

Russian adolescent drug use and comparisons to United States adolescents.

There is limited drug use data on Russian youth since the dissolution of the USSR. This study provides descriptive and comparative data for establishing initial baseline levels of Russian adolescent drug use. A convenience sample of 150 Russian adolescents (mean age = 15.4 years) was surveyed at a suburban Moscow secondary school during the fall of 1992. The findings showed that tobacco and alcohol were the most commonly used drugs, and that there were gender differences in their use. More Russian girls had used alcohol than Russian boys, while more boys had used tobacco and at an earlier average age than the girls. Tobacco and alcohol use between the Russian sample and United States samples was generally similar. Differences were attributed to age variations in the Russian and US samples.

Adolescents becoming adults: attributes for adulthood.

The research literature identifying the end of adolescence and the onset of adulthood has focused on event-related factors (e.g., marriage, occupation), while ignoring cognitive-related factors (e.g., responsibility for one's self and making decisions). This study addresses both realms. Adolescents (N = 113, M age = 16.5 years) were surveyed to determine what they believed were the most important attributes for becoming adults, and at what age their adulthood began. The sample perceived that adult status occurred at a mean age of 17.4 years (SD = 2.55) with 78.8% of the youth reporting that they were "adults." The majority of the sample identified cognitive factors as indicators of adulthood. Further analyses indicated that respondents who perceived that adulthood occurred at younger ages had higher levels of self-esteem. Implications of the consequences of adulthood attributes and beliefs for current and later life adjustment are discussed.

Couples and chronic obstructive airway diseases: the role of gender in coping and depression.

Social support, stress, health locus of control, active and avoidance coping, and depression were studied with 107 married couples in which one partner had a chronic obstructive airway disease (mean age = 62 years old). Differences between couples were evident when gender of the patient was assessed. Female patient couples that were older appeared more at risk than male patient couples for distress. In the analyses of spouse depression, gender moderated the relation of coping, social support, and health locus of control with depression. For patients, coping and social support were directly related to depression rather than moderated by gender. Implications for prevention and future research are discussed.

Racial influence in renal stone disease: a Saskatchewan story.

Data was obtained from two separate governement sources in an effort to review the prevalence of kidney stone disease in the province of Saskatchewan for the years 1983-1988 inclusive. The data revealed a statistally significant difference in prevalence rate among different ethnic groups within the population. Aboriginal people were found to have a prevalence rate approximately one-third that of the nonaboriginal (non-native) population. A renal stone episode prevalence of 0.858 per 1000 population compared to 0.222 per 1000 population in aboriginal people (p.<.001). The reasons for this difference could not be retrospectively associated with geographical variation. A discussion of other possible causes in association is offered, but it is felt that, in the end, more research into this area is required.

Parents' perceptions of their adolescence: implications for parent-youth conflict and family satisfaction.

This study examined the relation between parents' perceptions of "storm and stress" in their own adolescence and their current relationships with their children. A sample of 121 adolescents and their parents (106 mothers) were surveyed. Analysis indicated that over 48% of these parents viewed their adolescence as being stormy and stressful. Parents who experienced greater storm and stress as youth had more conflict in their relationships with their children and were less satisfied with their families. Implications for intergenerational theory and family intervention are presented.

Partner and grandmother contact in black and white teen parent families.

Contact of teen mothers with grandmothers and partners was studied as a predictor of maternal and middle childhood developmental outcomes. Mothers were interviewed yearly beginning in 1979 until 1986. Each child was given a developmental assessment in 1986. Black teens lived longer with their parents after the child's birth and white teens married earlier and had more disruptions in their relationships. Grandmother assistance with childcare was positively associated with the mother's ability to pursue her education. The findings suggested, however, that child developmental problems may occur when mothers routinely rely upon grandmother assistance into middle childhood, particularly for white families. In general, a male partner who had regular contact with the mother's child, more stimulation and support in the home environment, and higher educational level of the mother were associated with better child developmental outcomes.

Living near a hazardous waste facility: coping with individual and family distress.

Residents near a hazardous waste facility were interviewed about their level of distress and their involvement in a community organization concerned about toxic exposure. Specific beliefs about living near such a facility were related to individual and family distress and to participation in the organization. Implications for research and for clinical practice are discussed.

The role of family support in determining developmental outcomes in children of teen mothers.

Children from teen parent families are impaired developmentally compared to children of older mothers. Family support has frequently been proposed as a mediator of the stress that teen parents experience as a result of teen parenthood. This longitudinal study investigates the role of family support factors and maternal characteristics in relation to child outcomes (6-7 year old children) in teen parent families. Two models outlining the role of partner and grandmother family support are proposed to explain the process by which child development occurs within the family contexts of teen families. Implications of the results for intervention are discussed.