Localized thermonuclear bursts from accreting magnetic white dwarfs.

Nova explosions are caused by global thermonuclear runaways triggered in the surface layers of accreting white dwarfs1-3. It has been predicted4-6 that localized thermonuclear bursts on white dwarfs can also take place, similar to type-I X-ray bursts observed in accreting neutron stars. Unexplained rapid bursts from the binary system TV Columbae, in which mass is accreted onto a moderately strong magnetized white dwarf from a low-mass companion, have been observed on several occasions in the past 40 years7-11. During these bursts, the optical/ultraviolet luminosity increases by a factor of more than three in less than an hour and fades in around ten hours. Fast outflows have been observed in ultraviolet spectral lines7, with velocities of more than 3,500 kilometres per second, comparable to the escape velocity from the white dwarf surface. Here we report on optical bursts observed in TV Columbae and in two additional accreting systems, EI Ursae Majoris and ASASSN-19bh. The bursts have a total energy of approximately 10-6  times than those of classical nova explosions (micronovae) and bear a strong resemblance to type-I X-ray bursts12-14. We exclude accretion or stellar magnetic reconnection events as their origin and suggest thermonuclear runaway events in magnetically confined accretion columns as a viable explanation.

Regulative interactions between cells from different imaginal disks of Drosophila melanogaster.

The regulative behavior of cells from the imaginal wing disk of Drosophila melanogaster can be modified by interaction with cells from different disk types. Both thoracic and nonthoracic disks are able to interact, but there are major differences in the effectiveness of interaction. The finding lends experimental support to the idea that cells in different fields within the same organism use the same mechanism for specifying positional information. A similar conclusion has been reached by Wilcox and Smith based on studies of the mutation wingless.

Relationship of self-efficacy and binging to adherence to diabetes regimen among adolescents.

OBJECTIVE: To test the hypothesis that poorer adherence to diabetes care is related to four variables associated with self-concept in adolescents with diabetes: self-esteem, self-efficacy, depression, and binging behavior. In addition, we expected adolescent females to be less adherent to diabetes care. RESEARCH DESIGN AND METHODS: We recruited 193 consecutive patients (aged 13-18 yr) with insulin-dependent diabetes mellitus during their regular quarterly visit to a diabetes clinic in a large urban hospital. Participants completed the Rosenberg Self-Esteem Scale, the Children's Depression Inventory, an assessment of the frequency of binging in the past 3 mo, and parallel forms of an adherence scale and a self-efficacy scale that were developed for use in this study. RESULTS: Adolescents who reported lower adherence tended to report lower self-esteem (r = 0.45, P less than 0.001) and self-efficacy (r = 0.57, P less than 0.001), more depressive symptoms (r = -0.50, P less than 0.001), more binging (r = -0.36, P less than 0.001), and had higher HbA1c (r = -0.24, P less than 0.001) than those with higher adherence scores. Together, the psychological variables accounted for 50% of the variance in adherence. There was no sex difference in reported binging, but, as expected, adolescent females reported less adherence overall (F[7,184] = 2.5, P = 0.018). CONCLUSIONS: Treatment adherence in adolescents with insulin-dependent diabetes mellitus is associated with behavioral and psychological variables. These findings suggest that specific behavioral and cognitive interventions could be used to improve adherence in those individuals who lack confidence in their ability to perform diabetes-related tasks.

Brief clinical report: non-mosaic partial tetrasomy and partial trisomy 9.

Partial tetrasomy 9 is a very rare chromosome abnormality. Of the reported cases, most have had tetrasomy only of 9p arising from the formation of an isochromosome. In addition, mosaicism was found in five of the 12 previous cases. We report on a case of non-mosaic partial tetrasomy 9 involving all of the short arms and asymmetrical segments of the long arms.

Predictors of quality of life and adjustment after lung transplantation.

STUDY OBJECTIVE: Few studies have examined predictors of quality of life and adjustment after lung transplantation. This study determined whether pretransplant psychological measures predicted physical health, quality of life, and overall adjustment posttransplant. Cross-sectional analyses also examined differences in adjustment and quality of life for lung transplant candidates and recipients. DESIGN AND PARTICIPANTS: Seventeen transplant candidates and 60 transplant recipients completed questionnaires measuring adjustment and quality of life. In addition, we examined archival data on 107 transplant candidates who had received pretransplant psychological assessments, and posttransplant physical health status data were collected on these patients. Of the 107 patients who provided a pretransplant psychological assessment, 32 completed the questionnaires measuring posttransplant adjustment and quality of life. SETTING: University medical center transplant service. RESULTS: Cross-sectional analyses indicated significantly better adjustment and quality of life posttransplant. Pretransplant psychological variables were not associated with measures of posttransplant physical health. Hierarchical multiple regression analyses found that pretransplant anxiety and psychopathology predicted posttransplant adjustment (beta's ranging from 0.32 to 0.68) and greater pretransplant anxiety also predicted worse posttransplant quality of life (beta's ranging from 0.29 to 0.62). Subjective sleep disturbances were associated with poorer adjustment and quality of life (beta's ranging from 0.36 to 0.75), and were found to mediate the relationship between presurgical anxiety and posttransplant adjustment and quality of life. CONCLUSIONS: This study found that psychological status pretransplant predicted adjustment and quality of life posttransplant. Moreover, increased anxiety levels pretransplant predicted subsequent subjective sleep disturbances, which were, in turn, associated with poorer adjustment and quality of life. The benefits of pretransplant stress management interventions are discussed.

Influence of functional impairment and social support on depressive symptoms in persons with diabetes.

Tested the buffering model of social support among 158 adults with diabetes. We predicted that, among patients with higher levels of illness-related impairment, adequate social support would act as a buffer against depression. Measures included the Beck Depression Inventory; the Sickness Impact Profile; and an assessment of the adequacy of social support to enable the patient to deal with illness-related tasks, domestic chores, financial responsibilities, and emotional needs. Depressive symptoms correlated positively with functional impairment (r = .58, p less than .001) and negatively with the adequacy of social support (r = -.31, p less than .001). In addition, social support moderated depression in the face of greater impairment such that, among patients who reported the most illness-related functional disabilities, adequate support provided a relative protection from depression. The findings suggest that individuals with inadequate support are most at risk to become depressed when disability related to illness increases.

Quality of life following transplantation of the heart, liver, and lungs.

The purpose of this study was to describe the quality of life of patients who have received a transplant of the heart, liver, and lungs. We wished to document how the different patient groups fared in relation to each other with respect to physical, psychological, and social functioning, as well as in relation to published normative data. We also wished to identify factors that contribute to better functioning. We sent out a questionnaire by mail and received responses from 55 heart, 149 liver, and 59 lung transplant recipients (82% response rate). Measures included the SF-36, Mental Health Inventory, the State Anxiety Inventory, the UCLA Loneliness Scale-Revised, a quality of life measure that rated degree of improvement since transplantation, a measure of degree of difficulty in following medical and lifestyle regimens, sleep disturbance, and the Illness Intrusiveness Rating Scale. Results indicated that lung transplant patients reported better functioning than heart or liver transplant patients in all three domains of physical, psychological, and social functioning. Lung patients' level of functioning was equivalent to or better than published norms for the SF-36. Heart and liver recipients reported equivalent functioning to published norms in some domains, but reported impairment in the areas of physical and social functioning. Heart patients especially reported greater intrusiveness of their illness on their daily lives and indicated more difficulty complying with their lifestyle regimen. In all three groups, a large majority of patients reported feeling that life had improved since transplant with respect to health, energy level, activity level, and overall quality of life. Fewer patients reported improvements in the areas of sex life, marriage, family relationships, and social relationships. Where there were differences among the three patient groups, again it was the lung patients who reported more improvement in life since transplantation. Patients with better physical functioning tended to have more energy and pep, to be younger, to see themselves as being in better health, to feel less intrusion on their lives of their illness, and to be employed. Those with better psychological functioning tended to report less sleep disturbance, less loneliness, better social functioning, more vitality, and to be older. Better social functioning was associated with better mental health, less illness intrusiveness, and less role impairment as a result of physical or emotional factors. Relatively few patients-roughly a quarter of the total sample-reported that they were working either full or part time. We conclude that transplantation results in improved quality of life overall, but that problems persist for some patients in their physical and social functioning. Interventions aimed at improving rehabilitation in specific targeted areas may enable patients to resume a more fulfilling lifestyle posttransplant.

When a child dies: the sociobiology of bereavement.

According to modern evolutionary theory, the fitness of individuals consists of both their personal reproductive success and the reproductive success of those with whom they share genes in common. It follows that one of the most biologically costly events possible is the death of a child. This study investigated the grief intensity of bereaved parents and their immediate families using ratings made by 263 bereaved parents. Predictions were derived from sociobiological tenets relating to parental investment, paternal uncertainty, and the propagation potential of both parents and children. Consequently, it was found that mothers grieved more than fathers, healthy children were grieved for more than unhealthy children; male children were grieved for more than female children; health of child and sex of child interacted such that the pattern of grief intensity obtained was healthy male greater than healthy female = unhealthy female = unhealthy male; similar children were grieved for more than dissimilar children; maternal grandmothers grieved more than either maternal grandfathers or paternal grandmothers, who in turn grieved more than paternal grandfathers; and mothers' siblings grieved more than fathers' siblings.

Embryogenesis in hydra.

Embryogenesis in hydra includes a variable period of dormancy; and this period, as well as subsequent stages through hatching, takes place within a thick cuticle that hinders observation. Thus, although the early stages of development have been well-characterized qualitatively, the middle and later stages are only poorly understood. Here, we provide a detailed description of the stages of embryogenesis, including the time required to traverse each of the stages, and the changes that occur in the type and number of cells throughout the stages. The events of cleavage and gastrulation occur within the first 48 h. Cleavage is holoblastic and unipolar and leads to a single-layered coeloblastula. Gastrulation occurs by ingression and is followed by the deposition of the thick cuticle. Thereafter, during the variable period of dormancy ranging from 2-24 weeks, little occurs; the important events are the conversion of the outer layer into an ectoderm and the appearance of the interstitial cell lineage. During the last 2 days before hatching, the endoderm and gastric cavity form, while stem cells of the interstitial cell lineage proliferate and differentiate into neurons, nematocytes, and secretory cells. Finally, the cuticle cracks, and the hatchling enlarges and emerges from the cuticle as a functional animal. The formation of the gastric cavity and the hatching of the embryo are both explicable in terms of the osmotic behavior of the animal and the hydrostatic forces generated by this behavior. Characteristics of development that are common to hydra and triploblastic phyla are presented.

Psychological treatment of patients with end-stage pulmonary disease.

A significant number of patients with end stage respiratory disease experience symptoms of emotional distress, including depression, anxiety, and panic. This paper describes an approach to the psychological treatment of these symptoms based on cognitive behaviour therapy. The application of this approach to the treatment of panic is described as an illustration. The use of cognitive and behavioural techniques in a group setting with patients awaiting lung transplantation is described. The aim of the intervention is to provide patients with strategies to enhance their coping abilities, promote health, and improve their quality of life.

A survey of Colorado's migrant farmworkers: access to health care.

PIP: This report utilizes data collected in a 1986 sample survey of 329 adult (18 to 50 years old) migrant farmworkers in Colorado to determine their health needs, health services utilization, and overall access to care. Health needs include selected indices of medical, dental, nutrition, and reproductive health. About 1/4 of the population had no usual source of health care. Upstream states such as Colorado are responsible as the primary providers of health services for those who either have no source of health care at their home base or experience a variety of barriers in their attempts to access services. Women are most likely to have had a medical visit over the past 12 months and are more likely to have experienced hospitalization. Unfortunately, although their contact with medical professionals is more frequent, the family planning needs of women are not being met. A large disparity exists between ideal family size and number of pregnancies and live births. The findings of this survey document the inferior health status of the migrant farmworker population in Colorado. Hunger, poverty, and environmental hazards increase the risk of illness, while at the same time, barriers to care often prevent migrants from accessing needed health services. Recommendations include 1) promoting and funding family planning and reproductive health services for migrant farmworker women and their partners, 2) incorporating trained family planning promoters in the migrant health delivery system, 3) maintaining successful models of restorative dental care for adults, 4) increasing access to services in nontraditional settings, 5) increasing use of ancillary personnel to provide services, especially dental services, 6) maintaining outreach programs in the available food programs, and 7) encouraging migrant health programs to provide leadership in the development of alternative food sources.^ieng

Sex determination in hydra: control by a subpopulation of interstitial cells in Hydra oligactis males.

The stability of sexual phenotype was examined in a single clone of Hydra oligactis males maintained at two culture temperatures, 18 and 22 degrees C. At these temperatures animals of this species do not reproduce sexually, but reproduce asexually by budding, and males and females are morphologically indistinguishable. When the temperature is lowered to 10 degrees C gametogenesis is induced and sexual phenotype can be assayed. Males cultured for several years at 18 degrees C expressed a stable sexual phenotype when induced to undergo gametogenesis; males remained male. Those cultured at 22 degrees C for 1 year, however, expressed a low frequency of sex reversal from male to female; males ceased sperm differentiation and began producing eggs. Male sex reversal in cultures maintained at the higher temperature was correlated with the loss of a specific subpopulation of interstitial cells, those that bind the monoclonal antibody, AC2, which labels cells specific to the spermatogenic pathway in H. oligactis males. When interstitial cells restricted to this pathway were reintroduced into sex-reversed males (phenotypic females), the male phenotype was reestablished and animals reverted to sperm production. To further investigate the role of AC2+ cells in the masculinization of females, normal males (containing AC2+ cells) and sex-reversed males (lacking AC2+ cells) were grafted to females. In grafts between normal males and females, egg production ceased and sperm differentiation ensued, whereas those between sex-reversed males and females continued to produce eggs. Thus, the presence of AC2+ interstitial cells is strictly correlated with male sexual phenotypes and it is only in their absence that the female phenotype is expressed.

The interstitial cells control the sexual phenotype of heterosexual chimeras of hydra.

The three stem cell populations in hydra, the epithelial cells of the ectoderm and endoderm, which make up the body of the hydra, and the interstitial cells, which give rise to nerve cells, nematocytes, and gametes, were tested for their effects on determining the sexual phenotype of individuals. This was done by creating epithelial hydra, which are devoid of interstitial cells and their derivatives, of one sexual type and repopulating them with interstitial cells from individuals of the other sexual type. The resulting heterosexual chimeras were found in all cases to display the same sexual phenotype as that of the interstitial cell donor, indicating this cell type is responsible for the sex of the animal. The epithelial tissue had no influence in determining which gamete type was produced.

Germ cells in Hydra oligactis males. I. Isolation of a subpopulation of interstitial cells that is developmentally restricted to sperm production.

Single clones of interstitial cells were generated and analyzed to determine if one interstitial cell has the capacity to differentiate both somatic and germ cells. Such clones were produced by using hydroxyurea to selectively eliminate interstitial cells from normal Hydra oligactis males. The number of animals devoid of interstitial cells within the population was determined by staining whole animals with toluidine blue which renders the interstitial cells visible. The number of animals containing single clones of interstitial cells was then estimated using single hit Poisson statistics. In treatments which rendered 60-80% of the population devoid of interstitial cells, the majority of the animals containing interstitial cells lost the ability to produce somatic cells, including nerves and nematocytes, but retained the capacity to produce sperm. This result strongly suggests the presence of a separate germ line in hydra.

Bibliotherapy for psychosocial distress in lung transplant patients and their families.

Thirty-six lung transplant candidates (n = 16), recipients (n = 11), and support people (n = 9) were examined for psychological distress, coping style, and orientation to independent learning before and after receiving a self-help book in a program designed to alleviate psychosocial distress and bolster adaptive coping. The subjects rated the book as highly acceptable, and none reported increased psychological distress. A further six subjects completed initial psychological measures but elected not to us the book. These subjects were compared with study completers and found to have significantly higher disengagement scores on the Coping Strategies Inventory. Although uncontrolled, significant changes were observed in coping strategies used by the completer group. The relevance of these findings to the use of bibliotherapy in medically ill populations is discussed.

Germ cells in Hydra oligactis males. II. Evidence for a subpopulation of interstitial stem cells whose differentiation is limited to sperm production.

Animals containing germline-restricted interstitial cells were obtained by treating males from a clone of Hydra oligactis with hydroxyurea (HU) to lower the interstitial population to 1 or 2 cells per animal. A 3-day HU treatment produced animals whose interstitial cells did not form somatic cells, but did produce sperm. The isolation of these cells in HU-treated animals has lead us to propose that the interstitial cell population may contain subpopulations which possess different growth dynamics and developmental potentials. Through asexual propagation, we have cloned several animals containing only sperm precursor interstitial cells and have examined the growth and differentiation behavior of these cells in offspring propagated over a 2-year period. Evidence has been obtained which demonstrates (1) the extensive self-renewal capacity of the sperm precursor interstitial cells, and (2) the restricted differentiation capacity of these interstitial stem cells. Factors which affect cells entering and traversing the spermatogenic pathway are also presented.

Spermatogenesis in Hydra oligactis. II. How temperature controls the reciprocity of sexual and asexual reproduction.

Hydra oligactis undergo two mutually exclusive modes of reproduction: at warm temperatures (18-22 degrees C) animals reproduce asexually by budding, while at cold temperatures (10-12 degrees C) gamete differentiation occurs. Using a monoclonal antibody which is specific for cells of the sperm lineage, it was discovered that under conditions where sperm differentiation does not occur (18-22 degrees C), cells continually enter the sperm pathway but progression down the pathway is prematurely halted, effectively blocking the production of sperm. To elucidate the mechanism by which completion of sperm differentiation is controlled, the cell cycle times of interstitial cells entering the sperm pathway at both the restrictive (18 degrees C) and permissive (10 degrees C) temperatures were examined. It was envisaged that at the restrictive temperature the cell cycle times of committed cells would lengthen as they proceeded down the pathway, leading to dilution and eventual loss of cells at later stages of sperm differentiation. This did not occur. Although cells of the sperm lineage were found overall to divide more slowly at 18 degrees C than at 10 degrees C, at both temperatures the cell cycle times shortened as cells proceeded further down the pathway, making a dilution mechanism untenable. The effect of high temperature on the survival of cells was then tested by subjecting animals to a heat shock. Within 12 hr of the increase in temperature, the total number of sperm lineage interstitial cells dropped 10-fold while the total numbers of epithelial and somatic interstitial cells remained virtually unchanged. A distinct consequence of this cell loss was the disappearance of cells furthest down the sperm pathway. It is proposed that as cells move down the sperm pathway, they become increasingly sensitive to high temperature which adversely affects their survival; the higher the temperature, the earlier in the pathway cells die. The lethal effect is abolished by lowering the temperature, allowing sperm differentiation to continue to completion. The possible adaptive advantages of temperature controlling gametogenesis are discussed.

The Endstage Renal Disease Severity Index (ESRD-SI).

Measures of disease severity are required as experimental, control and outcome variables in studies of the psychosocial aspects of physical illness. The Endstage Renal Disease Severity Index (ESRD-SI) was developed for these purposes during a prospective study of patient adjustment to dialysis and endstage renal disease (ESRD). It was found to have adequate inter-rater reliability, test-retest reliability, and construct and predictive validity in two subsamples (total N = 233) of dialysis patients. The ESRD-SI is suitable as a sensitive indicator of disease severity in these patients.

Gene-culture coevolution of complex social behavior: human altruism and mate choice.

The hypothesis is examined that genes bias the development of complex social behavior in one direction over alternatives. Studies of altruism and political attitudes in twins estimate that approximately 50% of the variance is associated with direct genetic inheritance, virtually 0% with the twin's common family environment, and the remainder with each twin's specific environment. Studies of human marriages show that spouses choose each other on the basis of similarity, assorting on the most genetically influenced of a set of homogeneous attributes. These data imply a genetic canalization of social influences such that, within the constraints allowed by the total spectrum of cultural alternatives, people create environments maximally compatible with their genotypes.

Stress, social support, and symptoms of depression in spouses of the medically ill.

This study investigated the level and frequency of depressive symptoms in spouses of dialysis patients, as a function of a) severity of patient disease, b) level of stress experienced by the spouse, and c) perception of support from the ill partner. The subjects were forty patients who had begun dialysis in the last year and their spouses. Measures of depression, impact on family, perceived social support, and disease severity were applied. Significant depressive symptoms were reported by 20 percent of spouses. Symptom severity was not correlated with age, sex, or occupation of the spouses, nor with level of depression or functional impairment of the dialysis patients. The amount of social support received from the ill partner accounted for 37 percent of the variance in spouse depression, while social and financial stressors reported by the spouse explained 13 percent of the variance in spouse symptoms. These findings suggest that depressive symptoms in spouses of dialysis patients are associated with the social and economic consequences of the illness for the family but even more so with the amount of perceived support from the patient. The determinants of this perceived support need further exploration.