737 research outputs found

    Quantifying Bar Strength: Morphology Meets Methodology

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    A set of objective bar-classification methods have been applied to the Ohio State Bright Spiral Galaxy Survey (Eskridge et al. 2002). Bivariate comparisons between methods show that all methods agree in a statistical sense. Thus the distribution of bar strengths in a sample of galaxies can be robustly determined. There are very substantial outliers in all bivariate comparisons. Examination of the outliers reveals that the scatter in the bivariate comparisons correlates with galaxy morphology. Thus multiple measures of bar strength provide a means of studying the range of physical properties of galaxy bars in an objective statistical sense.Comment: LaTeX with Kluwer style file, 5 pages with 3 embedded figures. edited by Block, D.L., Freeman, K.C., Puerari, I., & Groess,

    Dying at home in Belgium: a descriptive GP interview study

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    <p>Abstract</p> <p>Background</p> <p>While increasing attention is being paid to enabling terminal patients to remain at home until death, limited information is available on the circumstances in which people at home actually die. Therefore this study aims to describe patient characteristics, functional and cognitive status and physical and psychological symptom burden in the last three months of life among Belgian patients dying at home, according to their GPs.</p> <p>Methods</p> <p>In 2005, a nationwide and retrospective interview study with GPs took place on people dying at home in Belgium as reported by Sentinel Network of GPs in Belgium. GPs registered all deaths (patients aged 1 year or more) weekly and were interviewed about all patients dying non-suddenly at home, using face-to-face structured interviews.</p> <p>Results</p> <p>Interviews were obtained on 205 patients (90% response rate). Between the second and third month before death, 55% were fully invalid or limited in self-care. In the last week of life, almost all were fully invalid. Fifty four percent were unconscious at some point during the last week; 46% were fully conscious. Most frequently reported symptoms were lack of energy, lack of appetite and feeling drowsy. Conditions most difficult for GPs to manage were shortness of breath, lack of energy and pain.</p> <p>Conclusions</p> <p>Many people dying at home under the care of their GPs in Belgium function relatively well until the last week of life and cognitive status seems to be preserved until the end in many cases. However, symptoms which GPs find difficult to control still manifest in many patients in the final week of life.</p

    Response of different PTH assays to therapy with sevelamer or CaCO3 and active vitamin D sterols

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    Amino-terminally truncated parathyroid hormone (PTH) fragments are detected to differing degrees by first- and second-generation immunometric PTH assays (PTH-IMAs), and acute changes in serum calcium affect the proportion of these fragments in circulation. However, the effect of chronic calcium changes and different vitamin D doses on these PTH measurements remains to be defined. In this study, 60 pediatric dialysis patients, aged 13.9 ± 0.7 years, with secondary hyperparathyroidism were randomized to 8 months of therapy with oral vitamin D combined with either calcium carbonate (CaCO3) or sevelamer. Serum phosphorus levels did not differ between groups. Serum calcium levels rose from 9.3 ± 0.1 to 9.7 ± 0.1 mg/dl during CaCO3 therapy (p < 0.01 from baseline) but remained unchanged during sevelamer therapy. In the CaCO3 and sevelamer groups, baseline serum PTH levels (1st PTH-IMA; Nichols Institute Diagnostics, San Clemente, CA) were 964 ± 75 and 932 ± 89 pg/ml, and levels declined to 491 ± 55 and 543 ± 59 pg/ml, respectively (nonsignificant between groups). Patients treated with sevelamer received higher doses of vitamin D than those treated with CaCO3. The PTH values obtained by first- and second-generation PTH-IMAs correlated closely throughout therapy and the response of PTH was similar to both PTH-IMAs, despite differences in serum calcium levels

    An RxLR effector from phytophthora infestans prevents re-localisation of two plant NAC transcription factors from the endoplasmic reticulum to the nucleus

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    The plant immune system is activated following the perception of exposed, essential and invariant microbial molecules that are recognised as non-self. A major component of plant immunity is the transcriptional induction of genes involved in a wide array of defence responses. In turn, adapted pathogens deliver effector proteins that act either inside or outside plant cells to manipulate host processes, often through their direct action on plant protein targets. To date, few effectors have been shown to directly manipulate transcriptional regulators of plant defence. Moreover, little is known generally about the modes of action of effectors from filamentous (fungal and oomycete) plant pathogens. We describe an effector, called Pi03192, from the late blight pathogen Phytophthora infestans, which interacts with a pair of host transcription factors at the endoplasmic reticulum (ER) inside plant cells. We show that these transcription factors are released from the ER to enter the nucleus, following pathogen perception, and are important in restricting disease. Pi03192 prevents the plant transcription factors from accumulating in the host nucleus, revealing a novel means of enhancing host susceptibility

    Regional Endothermy in a Coral Reef Fish?

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    Although a few pelagic species exhibit regional endothermy, most fish are regarded as ectotherms. However, we document significant regional endothermy in a benthic reef fish. Individual steephead parrotfish, Chlorurus microrhinos (Labridae, formerly Scaridae) were tagged and their internal temperatures were monitored for a 24 h period using active acoustic telemetry. At night, on the reef, C. microrhinos were found to maintain a consistent average peritoneal cavity temperature 0.16±0.005°C (SE) warmer than ambient. Diurnal internal temperatures were highly variable for individuals monitored on the reef, while in tank-based trials, peritoneal cavity temperatures tracked environmental temperatures. The mechanisms responsible for a departure of the peritoneal cavity temperature from environmental temperature occurred in C. microrhinos are not yet understood. However, the diet and behavior of the species suggests that heat in the peritoneal cavity may result primarily from endogenous thermogenesis coupled with physiological heat retention mechanisms. The presence of limited endothermy in C. microrhinos indicates that a degree of uncertainty may exist in the manner that reef fish respond to their thermal environment. At the very least, they do not always appear to respond to environmental temperatures as neutral thermal vessels and do display limited, but significant, visceral warming

    Building health research systems to achieve better health

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    Health research systems can link knowledge generation with practical concerns to improve health and health equity. Interest in health research, and in how health research systems should best be organised, is moving up the agenda of bodies such as the World Health Organisation. Pioneering health research systems, for example those in Canada and the UK, show that progress is possible. However, radical steps are required to achieve this. Such steps should be based on evidence not anecdotes. Health Research Policy and Systems (HARPS) provides a vehicle for the publication of research, and informed opinion, on a range of topics related to the organisation of health research systems and the enormous benefits that can be achieved. Following the Mexico ministerial summit on health research, WHO has been identifying ways in which it could itself improve the use of research evidence. The results from this activity are soon to be published as a series of articles in HARPS. This editorial provides an account of some of these recent key developments in health research systems but places them in the context of a distinguished tradition of debate about the role of science in society. It also identifies some of the main issues on which 'research on health research' has already been conducted and published, in some cases in HARPS. Finding and retaining adequate financial and human resources to conduct health research is a major problem, especially in low and middle income countries where the need is often greatest. Research ethics and agenda-setting that responds to the demands of the public are issues of growing concern. Innovative and collaborative ways are being found to organise the conduct and utilisation of research so as to inform policy, and improve health and health equity. This is crucial, not least to achieve the health-related Millennium Development Goals. But much more progress is needed. The editorial ends by listing a wide range of topics related to the above priorities on which we hope to feature further articles in HARPS and thus contribute to an informed debate on how best to achieve such progress

    Quantitative genetics of immunity and life history under different photoperiods

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    Insects with complex life-cycles should optimize age and size at maturity during larval development. When inhabiting seasonal environments, organisms have limited reproductive periods and face fundamental decisions: individuals that reach maturity late in season have to either reproduce at a small size or increase their growth rates. Increasing growth rates is costly in insects because of higher juvenile mortality, decreased adult survival or increased susceptibility to parasitism by bacteria and viruses via compromised immune function. Environmental changes such as seasonality can also alter the quantitative genetic architecture. Here, we explore the quantitative genetics of life history and immunity traits under two experimentally induced seasonal environments in the cricket Gryllus bimaculatus. Seasonality affected the life history but not the immune phenotypes. Individuals under decreasing day length developed slower and grew to a bigger size. We found ample additive genetic variance and heritability for components of immunity (haemocyte densities, proPhenoloxidase activity, resistance against Serratia marcescens), and for the life history traits, age and size at maturity. Despite genetic covariance among traits, the structure of G was inconsistent with genetically based trade-off between life history and immune traits (for example, a strong positive genetic correlation between growth rate and haemocyte density was estimated). However, conditional evolvabilities support the idea that genetic covariance structure limits the capacity of individual traits to evolve independently. We found no evidence for G × E interactions arising from the experimentally induced seasonality

    Secular Evolution and the Formation of Pseudobulges in Disk Galaxies

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    We review internal processes of secular evolution in galaxy disks, concentrating on the buildup of dense central features that look like classical, merger-built bulges but that were made slowly out of disk gas. We call these pseudobulges. As an existence proof, we review how bars rearrange disk gas into outer rings, inner rings, and gas dumped into the center. In simulations, this gas reaches high densities that plausibly feed star formation. In the observations, many SB and oval galaxies show central concentrations of gas and star formation. Star formation rates imply plausible pseudobulge growth times of a few billion years. If secular processes built dense central components that masquerade as bulges, can we distinguish them from merger-built bulges? Observations show that pseudobulges retain a memory of their disky origin. They have one or more characteristics of disks: (1) flatter shapes than those of classical bulges, (2) large ratios of ordered to random velocities indicative of disk dynamics, (3) small velocity dispersions, (4) spiral structure or nuclear bars in the bulge part of the light profile, (5) nearly exponential brightness profiles, and (6) starbursts. These structures occur preferentially in barred and oval galaxies in which secular evolution should be rapid. So the cleanest examples of pseudobulges are recognizable. Thus a large variety of observational and theoretical results contribute to a new picture of galaxy evolution that complements hierarchical clustering and merging.Comment: 92 pages, 21 figures in 30 Postscript files; to appear in Annual Review of Astronomy and Astrophysics, Vol. 42, 2004, in press; for a version with full resolution figures, see http://chandra.as.utexas.edu/~kormendy/ar3ss.htm
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