318 research outputs found
A rapidly spinning supermassive black hole at the centre of NGCâ1365
Broad X-ray emission lines from neutral and partially ionized iron observed in active galaxies have been interpreted as fluorescence produced by the reflection of hard X-rays off the inner edge of an accretion disk. In this model, line broadening and distortion result from rapid rotation and relativistic effects near the black hole, the line shape being sensitive to its spin. Alternative models in which the distortions result from absorption by intervening structures provide an equally good description of the data, and there has been no general agreement on which is correct. Recent claims that the black hole (2âĂâ10^6 solar masses) at the centre of the galaxy NGCâ1365 is rotating at close to its maximum possible speed rest on the assumption of relativistic reflection. Here we report X-ray observations of NGCâ1365 that reveal the relativistic disk features through broadened Fe-line emission and an associated Compton scattering excess of 10â30 kiloelectronvolts. Using temporal and spectral analyses, we disentangle continuum changes due to time-variable absorption from reflection, which we find arises from a region within 2.5 gravitational radii of the rapidly spinning black hole. Absorption-dominated models that do not include relativistic disk reflection can be ruled out both statistically and on physical grounds
Social research on neglected diseases of poverty: Continuing and emerging themes
Copyright: © 2009 Manderson et al.Neglected tropical diseases (NTDs) exist and persist for social and economic reasons that enable the vectors and pathogens to take advantage of changes in the behavioral and physical environment. Persistent poverty at household, community, and national levels, and inequalities within and between sectors, contribute to the perpetuation and re-emergence of NTDs. Changes in production and habitat affect the physical environment, so that agricultural development, mining and forestry, rapid industrialization, and urbanization all result in changes in human uses of the environment, exposure to vectors, and vulnerability to infection. Concurrently, political instability and lack of resources limit the capacity of governments to manage environments, control disease transmission, and ensure an effective health system. Social, cultural, economic, and political factors interact and influence government capacity and individual willingness to reduce the risks of infection and transmission, and to recognize and treat disease. Understanding the dynamic interaction of diverse factors in varying contexts is a complex task, yet critical for successful health promotion, disease prevention, and disease control. Many of the research techniques and tools needed for this purpose are available in the applied social sciences. In this article we use this term broadly, and so include behavioral, population and economic social sciences, social and cultural epidemiology, and the multiple disciplines of public health, health services, and health policy and planning. These latter fields, informed by foundational social science theory and methods, include health promotion, health communication, and heath education
Baseline Religion Involvement Predicts Subsequent Salivary Cortisol Levels Among Male But not Female Black Youth
Background: Compared to Whites, Blacks are exposed to higher levels of chronic stress in the United States. As a result, major Black-White differences exist in the baseline and response of cortisol. Yet, the potential association between baseline religiosity and subsequent cortisol levels of Blacks are not known. Objectives: In the current study we aimed to determine the association between baseline religious behaviors and daytime salivary cortisol level among male and female Black youth. Materials and Methods: With a longitudinal design, data came from wave 1 (1994) and wave 6 (2000) of a cohort from an urban area in the Midwest of the United States. The study followed 227 Black adolescents (109 males and 118 females) for six years. Socio-demographics and religious behaviors (frequency of participation in religious activities) were measured at baseline. Base morning cortisol level at wave 6 was the outcome. We fitted a linear regression model to test the association between baseline religiosity at wave 1 and cortisol level at wave 6, while baseline age, socio-economics, and psychological symptoms were controlled. Results: In the pooled sample, frequency of participation in religious activities at baseline was negatively associated with mean cortisol level at follow up (r = -0.29, P > 0.01) among all, males (r = -0.38, P > 0.01), but not females (r = -.20, P > 0.05). Frequency of participation in religious activities remained a significant predictor of subsequent cortisol level (b = -0.283, 95% CI = -.107 - -0.022) while the effect of age, socioeconomics, and psychological symptoms were controlled. We could only find such an association among male Black youth (b = -0.368, 95% CI = -0.148 - -0.024) but not female Black youth (b = -0.229, 95% CI = -.113 - 0.011). Conclusions: Religiosity has been used as a coping mechanism among Blacks. Religiosity may also be related to stress regulation among Black youth. Future studies need to test complex associations between race, sex, religiosity, chronic stress, coping, and function of hypothalamo-pituitary-adrenal (HPA). It is not known whether male Black youth who are and those who are not religious differently cope with stress associated with daily discrimination and living in disadvantaged neighborhoods
Key stages in mammary gland development - Involution: apoptosis and tissue remodelling that convert the mammary gland from milk factory to a quiescent organ
Involution of the mammary gland is an essential process that removes the milk-producing epithelial cells when they become redundant at weaning. It is a two-step process that involves the death of the secretory epithelium and its replacement by adipo-cytes. During the first phase, remodelling is inhibited and apoptotic cells can be seen in the lumena of the alveoli. In the second phase, apoptosis is accompanied by remodelling of the surrounding stroma and re-differentiation of the adipocytes. Considerable effort has been directed towards understanding the molecular mechanisms of the involution process and this has resulted in the identification of the principal signalling pathways involved
Pretense and Imagination
Issues of pretense and imagination are of central interest to philosophers, psychologists, and researchers in allied fields. In this entry, we provide a roadmap of some of the central themes around which discussion has been focused. We begin with an overview of pretense, imagination, and the relationship between them. We then shift our attention to the four specific topics where the disciplines' research programs have intersected or where additional interactions could prove mutually beneficial: the psychological underpinnings of performing pretense and of recognizing pretense, the cognitive capacities involved in imaginative engagement with fictions, and the real-world impact of make-believe. In the final section, we discuss more briefly a number of other mental activities that arguably involve imagining, including counterfactual reasoning, delusions, and dreaming
A framework for the extraction and modeling of fact-finding reasoning from legal decisions: lessons from the Vaccine/Injury Project Corpus
This article describes the Vaccine/Injury Project Corpus, a collection of legal decisions awarding or denying compensation for health injuries allegedly due to vaccinations, together with models of the logical structure of the reasoning of the factfinders in those cases. This unique corpus provides useful data for formal and informal logic theory, for natural-language research in linguistics, and for artificial intelligence research. More importantly, the article discusses lessons learned from developing protocols for manually extracting the logical structure and generating the logic models. It identifies sub-tasks in the extraction process, discusses challenges to automation, and provides insights into possible solutions for automation. In particular, the framework and strategies developed here, together with the corpus data, should allow top-down and contextual approaches to automation, which can supplement bottom-up linguistic approaches. Illustrations throughout the article use examples drawn from the Corpus
Cues for Early Social Skills: Direct Gaze Modulates Newborns' Recognition of Talking Faces
Previous studies showed that, from birth, speech and eye gaze are two important
cues in guiding early face processing and social cognition. These studies tested
the role of each cue independently; however, infants normally perceive speech
and eye gaze together. Using a familiarization-test procedure, we first
familiarized newborn infants (nâ=â24) with videos of
unfamiliar talking faces with either direct gaze or averted gaze. Newborns were
then tested with photographs of the previously seen face and of a new one. The
newborns looked longer at the face that previously talked to them, but only in
the direct gaze condition. These results highlight the importance of both speech
and eye gaze as socio-communicative cues by which infants identify others. They
suggest that gaze and infant-directed speech, experienced together, are powerful
cues for the development of early social skills
Long Term Stabilization of Expanding Aortic Aneurysms by a Short Course of Cyclosporine A through Transforming Growth Factor-Beta Induction
Abdominal aortic aneurysms (AAAs) expand as a consequence of extracellular matrix destruction, and vascular smooth muscle cell (VSMC) depletion. Transforming growth factor (TGF)-beta 1 overexpression stabilizes expanding AAAs in rat. Cyclosporine A (CsA) promotes tissue accumulation and induces TGF -beta1 and, could thereby exert beneficial effects on AAA remodelling and expansion. In this study, we assessed whether a short administration of CsA could durably stabilize AAAs through TGF-beta induction. We showed that CsA induced TGF-beta1 and decreased MMP-9 expression dose-dependently in fragments of human AAAs in vitro, and in animal models of AAA in vivo. CsA prevented AAA formation at 14 days in the rat elastase (diameter increase: CsA: 131.9±44.2%; vehicle: 225.9±57.0%, Pâ=â0.003) and calcium chloride mouse models (diameters: CsA: 0.72±0.14 mm; vehicle: 1.10±0.11 mm, Pâ=â.008), preserved elastic fiber network and VSMC content, and decreased inflammation. A seven day administration of CsA stabilized formed AAAs in rats seven weeks after drug withdrawal (diameter increase: CsA: 14.2±15.1%; vehicle: 45.2±13.7%, Pâ=â.017), down-regulated wall inflammation, and increased αSMA-positive cell content. Co-administration of a blocking anti-TGF-beta antibody abrogated CsA impact on inflammation, αSMA-positive cell accumulation and diameter control in expanding AAAs. Our study demonstrates that pharmacological induction of TGF-beta1 by a short course of CsA administration represents a new approach to induce aneurysm stabilization by shifting the degradation/repair balance towards healing
Research in progress: report on the ICAIL 2017 doctoral consortium
This paper arose out of the 2017 international conference on AI and law doctoral consortium. There were five students who presented their Ph.D. work, and each of them has contributed a section to this paper. The paper offers a view of what topics are currently engaging students, and shows the diversity of their interests and influences
Loss of protein kinase C delta alters mammary gland development and apoptosis
As apoptotic pathways are commonly deregulated in breast cancer, exploring how mammary gland cell death is regulated is critical for understanding human disease. We show that primary mammary epithelial cells from protein kinase C delta (PKCÎŽ) â/â mice have a suppressed response to apoptotic agents in vitro. In the mammary gland in vivo, apoptosis is critical for ductal morphogenesis during puberty and involution following lactation. We have explored mammary gland development in the PKCÎŽ â/â mouse during these two critical windows. Branching morphogenesis was altered in 4- to 6-week-old PKCÎŽ â/â mice as indicated by reduced ductal branching; however, apoptosis and proliferation in the terminal end buds was unaltered. Conversely, activation of caspase-3 during involution was delayed in PKCÎŽ â/â mice, but involution proceeded normally. The thymus also undergoes apoptosis in response to physiological signals. A dramatic suppression of caspase-3 activation was observed in the thymus of PKCÎŽ â/â mice treated with irradiation, but not mice treated with dexamethasone, suggesting that there are both target- and tissue-dependent differences in the execution of apoptotic pathways in vivo. These findings highlight a role for PKCÎŽ in both apoptotic and nonapoptotic processes in the mammary gland and underscore the redundancy of apoptotic pathways in vivo
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