A stochastic model for particle impingements on orbiting spacecraft

A general methodology for simulating particle impingements on orbiting spacecraft is developed. Major steps in the modeling process are presented as (1) modeling objective, (2) construction of the spacecraft geometrical model, (3) simulation of the particles in the space environment, (4) particle impact and subsequent events of interest, and (5) results of the simulation. A simulation of the expected meteoroid impingements on the Hubble Space Telescope and the resulting angular momentum transfers which can cause telescope pointing disturbances is given to illustrate these methods

Measurement of the half-life of the T=12\frac{1}{2} mirror decay of 19^{19}Ne and its implication on physics beyond the standard model

The $\frac{1}{2}^+ \rightarrow \frac{1}{2}^+$ superallowed mixed mirror decay of $^{19}$Ne to $^{19}$F is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be $T_{1/2}$ = $17.2832 \pm 0.0051_{(stat)}$ $\pm 0.0066_{(sys)}$ s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.Comment: 5 pages, 3 figures, 1 tabl

Evolution of the number of accreting white dwarfs with shell nuclear burning and of occurrence rate of SN Ia

We analyze temporal evolution of the number of accreting white dwarfs with shell hydrogen burning in semidetached and detached binaries. We consider a stellar system in which star formation lasts for 10 Gyr with a constant rate, as well as a system in which the same amount of stars is formed in a single burst lasting for 1 Gyr. Evolution of the number of white dwarfs is confronted to the evolution of occurrence rate of events that usually are identified with SN Ia or accretion-induced collapses, i.e. with accumulation of Chandrasekhar mass by a white dwarf or a merger of a pair of CO white dwarfs with total mass not lower than the Chandrasekhar one. In the systems with a burst of star formation, at $t=$10 Gyr observed supersoft X-ray sources, most probably, are not precursors of SN Ia. The same is true for an overwhelming majority of the sources in the systems with constant star formation rate. In the systems of both kinds mergers of white dwarfs is the dominant SN Ia scenario. In symbiotic binaries, accreting CO-dwarfs do not accumulate enough mass for SN Ia explosion, while ONeMg-dwarfs finish their evolution by an accretion-induced collapse with formation of a neutron star.Comment: 11 pages, 2 figures, accepted by Astronomy Letter

Infrared Properties of Cataclysmic Variables from 2MASS: Results from the 2nd Incremental Data Release

Because accretion-generated luminosity dominates the radiated energy of most cataclysmic variables, they have been ``traditionally'' observed primarily at short wavelengths. Infrared observations of cataclysmic variables contribute to the understanding of key system components that are expected to radiate at these wavelengths, such as the cool outer disk, accretion stream, and secondary star. We have compiled the J, H, and Ks photometry of all cataclysmic variables located in the sky coverage of the 2 Micron All Sky Survey (2MASS) 2nd Incremental Data Release. This data comprises 251 systems with reliably identified near-IR counterparts and S/N > 10 photometry in one or more of the three near-IR bands.Comment: 2 pages, including 1 figure. To appear in the proceedings of The Physics of Cataclysmic Variables and Related Objects, Goettingen, Germany. For our followup ApJ paper (in press), also see http://www.ctio.noao.edu/~hoard/research/2mass/index.htm

Standardized Outcomes in Nephrology-Transplantation: A Global Initiative to Develop a Core Outcome Set for Trials in Kidney Transplantation.

BACKGROUND: Although advances in treatment have dramatically improved short-term graft survival and acute rejection in kidney transplant recipients, long-term graft outcomes have not substantially improved. Transplant recipients also have a considerably increased risk of cancer, cardiovascular disease, diabetes, and infection, which all contribute to appreciable morbidity and premature mortality. Many trials in kidney transplantation are short-term, frequently use unvalidated surrogate endpoints, outcomes of uncertain relevance to patients and clinicians, and do not consistently measure and report key outcomes like death, graft loss, graft function, and adverse effects of therapy. This diminishes the value of trials in supporting treatment decisions that require individual-level multiple tradeoffs between graft survival and the risk of side effects, adverse events, and mortality. The Standardized Outcomes in Nephrology-Transplantation initiative aims to develop a core outcome set for trials in kidney transplantation that is based on the shared priorities of all stakeholders. METHODS: This will include a systematic review to identify outcomes reported in randomized trials, a Delphi survey with an international multistakeholder panel (patients, caregivers, clinicians, researchers, policy makers, members from industry) to develop a consensus-based prioritized list of outcome domains and a consensus workshop to review and finalize the core outcome set for trials in kidney transplantation. CONCLUSIONS: Developing and implementing a core outcome set to be reported, at a minimum, in all kidney transplantation trials will improve the transparency, quality, and relevance of research; to enable kidney transplant recipients and their clinicians to make better-informed treatment decisions for improved patient outcomes

Distribution of Capillary Transit Times in Isolated Lungs of Oxygen-Tolerant Rats

Rats pre-exposed to 85% O2 for 5–7 days tolerate the otherwise lethal effects of 100% O2. The objective was to evaluate the effect of rat exposure to 85% O2 for 7 days on lung capillary mean transit time (t¯c) and distribution of capillary transit times (h c(t)). This information is important for subsequent evaluation of the effect of this hyperoxia model on the redox metabolic functions of the pulmonary capillary endothelium. The venous concentration vs. time outflow curves of fluorescein isothiocyanate labeled dextran (FITC-dex), an intravascular indicator, and coenzyme Q1 hydroquinone (CoQ1H2), a compound which rapidly equilibrates between blood and tissue on passage through the pulmonary circulation, were measured following their bolus injection into the pulmonary artery of isolated perfused lungs from rats exposed to room air (normoxic) or 85% O2 for 7 days (hyperoxic). The moments (mean transit time and variance) of the measured FITC-dex and CoQ1H2 outflow curves were determined for each lung, and were then used in a mathematical model [Audi et al. J. Appl. Physiol. 77: 332–351, 1994] to estimate t¯c and the relative dispersion (RDc) of h c(t). Data analysis reveals that exposure to hyperoxia decreases lung t¯c by 42% and increases RDc, a measure h c(t) heterogeneity, by 40%

Ovine pedomics : the first study of the ovine foot 16S rRNA-based microbiome

We report the first study of the bacterial microbiome of ovine interdigital skin based on 16S rRNA by pyrosequencing and conventional cloning with Sanger-sequencing. Three flocks were selected, one a flock with no signs of footrot or interdigital dermatitis, a second flock with interdigital dermatitis alone and a third flock with both interdigital dermatitis and footrot. The sheep were classified as having either healthy interdigital skin (H), interdigital dermatitis (ID) or virulent footrot (VFR). The ovine interdigital skin bacterial community varied significantly by flock and clinical condition. The diversity and richness of operational taxonomic units was greater in tissue from sheep with ID than H or VFR affected sheep. Actinobacteria, Bacteriodetes, Firmicutes and Proteobacteria were the most abundant phyla comprising 25 genera. Peptostreptococcus, Corynebacterium and Staphylococcus were associated with H, ID and VFR respectively. Sequences of Dichelobacter nodosus, the causal agent of ovine footrot, were not amplified due to mismatches in the 16S rRNA universal forward primer (27F). A specific real time PCR assay was used to demonstrate the presence of D. nodosus which was detected in all samples including the flock with no signs of ID or VFR. Sheep with ID had significantly higher numbers of D. nodosus (104-109 cells/g tissue) than those with H or VFR feet

Evo-devo of human adolescence: beyond disease models of early puberty

Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research

Display of probability densities for data from a continuous distribution

Based on cumulative distribution functions, Fourier series expansion and Kolmogorov tests, we present a simple method to display probability densities for data drawn from a continuous distribution. It is often more efficient than using histograms.Comment: 5 pages, 4 figures, presented at Computer Simulation Studies XXIV, Athens, GA, 201

Complement is activated in progressive multiple sclerosis cortical grey matter lesions

The symptoms of multiple sclerosis (MS) are caused by damage to myelin and nerve cells in the brain and spinal cord. Inflammation is tightly linked with neurodegeneration, and it is the accumulation of neurodegeneration that underlies increasing neurological disability in progressive MS. Determining pathological mechanisms at play in MS grey matter is therefore a key to our understanding of disease progression