38 research outputs found
INTRA- AND INTERRATER RELIABILITY OF MORPHOLOGICALLY EVALUATED LYMPHOCYTE APOPTOSIS IN TRAINED AND UNTRAINED OBSERVERS
Exercise-induced lymphocyte apoptosis has been reported using biochemical analysis and morphological assessment. Morphological evaluation is limited by the subjective nature of the technique. This investigation evaluated the intra- and interrater reliability of trained and untrained observers assessing apoptosis morphologically. Blood smears at baseline (PRE) and following cycle ergometer exercise (POST) were assessed microscopically for each condition. To obtain reliability measures, cell sets were evaluated for morphological characteristics of apoptosis on two separate occasions by trained and untrained observers using the intraclass correlation coefficient. Test-retest reliability for trained observers was higher for both conditions than untrained observers. Interrater reliability was below-average or below acceptable regardless of training status. Exercise may induce apoptotic changes in lymphocytes that are more easily discriminated by trained observers. Investigations assessing exercise-induced apoptosis should train observers in order to produce reliable results, and a single trained observer would be expected to yield the most reliable results
Presupernova Structure of Massive Stars
Issues concerning the structure and evolution of core collapse progenitor
stars are discussed with an emphasis on interior evolution. We describe a
program designed to investigate the transport and mixing processes associated
with stellar turbulence, arguably the greatest source of uncertainty in
progenitor structure, besides mass loss, at the time of core collapse. An
effort to use precision observations of stellar parameters to constrain
theoretical modeling is also described.Comment: Proceedings for invited talk at High Energy Density Laboratory
Astrophysics conference, Caltech, March 2010. Special issue of Astrophysics
and Space Science, submitted for peer review: 7 pages, 3 figure
Existential Communication and Leadership
The aim of this article is to introduce and explain a number of important existentialist philosophers and concepts that we believe can contribute to a critical approach to leadership theory. Emphasis is placed on understanding the nature of communication from an existentialist perspective and so Jaspers' conceptualization of existential communication is introduced along with important related concepts that may be regarded as important facets of leader communication including Being-in-the-world, the Other, intersubjectivity, dialogue and indirect communication. Particular attention is paid to Buber's ideas on communication as relationship and dialogue. Throughout, reference is made to contemporary, and what is often regarded as orthodox, thinking regarding the centrality of communication to leadership practice as a means by which to highlight the salience of an existentialist analysis
Spherically symmetric dissipative anisotropic fluids: A general study
The full set of equations governing the evolution of self--gravitating
spherically symmetric dissipative fluids with anisotropic stresses is deployed
and used to carry out a general study on the behaviour of such systems, in the
context of general relativity. Emphasis is given to the link between the Weyl
tensor, the shear tensor, the anisotropy of the pressure and the density
inhomogeneity. In particular we provide the general, necessary and sufficient,
condition for the vanishing of the spatial gradients of energy density, which
in turn suggests a possible definition of a gravitational arrow of time. Some
solutions are also exhibited to illustrate the discussion.Comment: 28 pages Latex. To appear in Phys.Rev.
Optical Light Curves of Supernovae
Photometry is the most easily acquired information about supernovae. The
light curves constructed from regular imaging provide signatures not only for
the energy input, the radiation escape, the local environment and the
progenitor stars, but also for the intervening dust. They are the main tool for
the use of supernovae as distance indicators through the determination of the
luminosity. The light curve of SN 1987A still is the richest and longest
observed example for a core-collapse supernova. Despite the peculiar nature of
this object, as explosion of a blue supergiant, it displayed all the
characteristics of Type II supernovae. The light curves of Type Ib/c supernovae
are more homogeneous, but still display the signatures of explosions in massive
stars, among them early interaction with their circumstellar material. Wrinkles
in the near-uniform appearance of thermonuclear (Type Ia) supernovae have
emerged during the past decade. Subtle differences have been observed
especially at near-infrared wavelengths. Interestingly, the light curve shapes
appear to correlate with a variety of other characteristics of these
supernovae. The construction of bolometric light curves provides the most
direct link to theoretical predictions and can yield sorely needed constraints
for the models. First steps in this direction have been already made.Comment: To be published in:"Supernovae and Gamma Ray Bursters", Lecture Notes
in Physics (http://link.springer.de/series/lnpp
Supernova Interaction with a Circumstellar Medium
The explosion of a core collapse supernova drives a powerful shock front into
the wind from the progenitor star. A layer of shocked circumstellar gas and
ejecta develops that is subject to hydrodynamic instabilities. The hot gas can
be observed directly by its X-ray emission, some of which is absorbed and
re-radiated at lower frequencies by the ejecta and the circumstellar gas.
Synchrotron radiation from relativistic electrons accelerated at the shock
fronts provides information on the mass loss density if free-free absorption
dominates at early times or the size of the emitting region if synchrotron
self-absorption dominates. Analysis of the interaction leads to information on
the density and structure of the ejecta and the circumstellar medium, and the
abundances in these media. The emphasis here is on the physical processes
related to the interaction.Comment: 22 pages, 7 figures, to appear as a Chapter in "Supernovae and
Gamma-Ray Bursts," edited by K. W. Weiler (Springer-Verlag
The Value of Rare Genetic Variation in the Prediction of Common Obesity in European Ancestry Populations
Polygenic risk scores (PRSs) aggregate the effects of genetic variants across the genome and are used to predict risk of complex diseases, such as obesity. Current PRSs only include common variants (minor allele frequency (MAF) ≥1%), whereas the contribution of rare variants in PRSs to predict disease remains unknown. Here, we examine whether augmenting the standard common variant PRS (PRScommon) with a rare variant PRS (PRSrare) improves prediction of obesity. We used genome-wide genotyped and imputed data on 451,145 European-ancestry participants of the UK Biobank, as well as whole exome sequencing (WES) data on 184,385 participants. We performed single variant analyses (for both common and rare variants) and gene-based analyses (for rare variants) for association with BMI (kg/m2), obesity (BMI ≥ 30 kg/m2), and extreme obesity (BMI ≥ 40 kg/m2). We built PRSscommon and PRSsrare using a range of methods (Clumping+Thresholding [C+T], PRS-CS, lassosum, gene-burden test). We selected the best-performing PRSs and assessed their performance in 36,757 European-ancestry unrelated participants with whole genome sequencing (WGS) data from the Trans-Omics for Precision Medicine (TOPMed) program. The best-performing PRScommon explained 10.1% of variation in BMI, and 18.3% and 22.5% of the susceptibility to obesity and extreme obesity, respectively, whereas the best-performing PRSrare explained 1.49%, and 2.97% and 3.68%, respectively. The PRSrare was associated with an increased risk of obesity and extreme obesity (ORobesity = 1.37 per SDPRS, Pobesity = 1.7x10-85; ORextremeobesity = 1.55 per SDPRS, Pextremeobesity = 3.8x10-40), which was attenuated, after adjusting for PRScommon (ORobesity = 1.08 per SDPRS, Pobesity = 9.8x10-6; ORextremeobesity= 1.09 per SDPRS, Pextremeobesity = 0.02). When PRSrare and PRScommon are combined, the increase in explained variance attributed to PRSrare was small (incremental Nagelkerke R2 = 0.24% for obesity and 0.51% for extreme obesity). Consistently, combining PRSrare to PRScommon provided little improvement to the prediction of obesity (PRSrare AUC = 0.591; PRScommon AUC = 0.708; PRScombined AUC = 0.710). In summary, while rare variants show convincing association with BMI, obesity and extreme obesity, the PRSrare provides limited improvement over PRScommon in the prediction of obesity risk, based on these large populations
Serum magnesium and calcium levels in relation to ischemic stroke : Mendelian randomization study
ObjectiveTo determine whether serum magnesium and calcium concentrations are causally associated with ischemic stroke or any of its subtypes using the mendelian randomization approach.MethodsAnalyses were conducted using summary statistics data for 13 single-nucleotide polymorphisms robustly associated with serum magnesium (n = 6) or serum calcium (n = 7) concentrations. The corresponding data for ischemic stroke were obtained from the MEGASTROKE consortium (34,217 cases and 404,630 noncases).ResultsIn standard mendelian randomization analysis, the odds ratios for each 0.1 mmol/L (about 1 SD) increase in genetically predicted serum magnesium concentrations were 0.78 (95% confidence interval [CI] 0.69-0.89; p = 1.3
7 10-4) for all ischemic stroke, 0.63 (95% CI 0.50-0.80; p = 1.6
7 10-4) for cardioembolic stroke, and 0.60 (95% CI 0.44-0.82; p = 0.001) for large artery stroke; there was no association with small vessel stroke (odds ratio 0.90, 95% CI 0.67-1.20; p = 0.46). Only the association with cardioembolic stroke was robust in sensitivity analyses. There was no association of genetically predicted serum calcium concentrations with all ischemic stroke (per 0.5 mg/dL [about 1 SD] increase in serum calcium: odds ratio 1.03, 95% CI 0.88-1.21) or with any subtype.ConclusionsThis study found that genetically higher serum magnesium concentrations are associated with a reduced risk of cardioembolic stroke but found no significant association of genetically higher serum calcium concentrations with any ischemic stroke subtype
Serum levels of anti-CCP antibodies, anti-MCV antibodies and RF IgA in the follow-up of patients with rheumatoid arthritis treated with rituximab
Macrosocial determinants of population health in the context of globalization
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55738/1/florey_globalization_2007.pd