261 research outputs found

    Thermal control characteristics of a diffuse bladed specular base louver system Final report

    Get PDF
    Diffuse bladed specular base louver system for spacecraft temperature contro

    Surface Hydrogen Modeling of Super Soft X-ray Sources: Are They Supernova Ia Progenitors?

    Full text link
    Nova explosions occur on the white dwarf (WD) component of a Cataclysmic Variable stellar system which is accreting matter lost by a companion. A Type Ia supernova explosion is thought to result when a WD, in a similar binary configuration, grows in mass to the Chandrasekhar Limit. Here, we present calculations of accretion of Solar matter, at a variety of mass accretion rates, onto hot (2.3×1052.3 \times 10^{5}K), luminous (30L_\odot), massive (1.25M_\odot, 1.35M_\odot) Carbon-Oxygen WDs. In contrast to our nova simulations where the WD has a low initial luminosity and a thermonuclear runaway (TNR) occurs and ejects material, these simulations do not eject material (or only a small fraction of the accreted material) and the WD grows in mass. A hydrogen TNR does not occur because hydrogen fuses to helium in the surface layers, and we call this process Surface Hydrogen Burning (SHB). As the helium layer grows in mass, it gradually fuses either to carbon and oxygen or to more massive nuclei depending on the WD mass and mass accretion rate. If such a WD were to explode in a SN Ia event, therefore, it would show neither hydrogen nor helium in its spectrum as is observed. Moreover, the luminosities and effective temperatures of our simulations agree with the observations of some of the Super Soft X-ray Binary Sources and, therefore, our results strengthen previous speculation that some of them (CAL 83 and CAL 87 for example) are probably progenitors of SN Ia explosions. Finally, we have achieved SHB for values of the mass accretion rate that almost span the observed values of the Cataclysmic Variables.Comment: Accepted by APJL, 4 pages, 1 figure, LaTex (uses emulateapj.sty

    The Plasminogen Activation System and the Regulation of Catecholaminergic Function

    Get PDF
    The local environment of neurosecretory cells contains the major components of the plasminogen activation system, including the plasminogen activators, tissue plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA), as well as binding sites for t-PA, the receptor for u-PA (uPAR), and also the plasminogen activator inhibitor, PAI-1. Furthermore, these cells express specific binding sites for plasminogen, which is available in the circulation and in interstitial fluid. Colocalization of plasminogen and its activators on cell surfaces provides a mechanism for promoting local plasminogen activation. Plasmin is retained on the cell surface where it is protected from its inhibitor, α2-antiplasmin. In neurosecretory cells, localized plasmin activity provides a mechanism for extracellular processing of secreted hormones. Neurotransmitter release from catecholaminergic cells is negatively regulated by cleavage products formed by plasmin-mediated proteolysis. Recently, we have identified a major plasminogen receptor, Plg-RKT. We have found that Plg-RKT is highly expressed in chromaffin cells of the adrenal medulla as well as in other catecholaminergic cells and tissues. Plg-RKT-dependent plasminogen activation plays a key role in regulating catecholaminergic neurosecretory cell function

    The Influence of Exercise Intensity On Post-Exercise Appetite Response

    Get PDF
    Please view abstract in the attached PDF file

    Assessing the Effect of Four Types of Direct Mail Messages to Promote the Uptake of Residential Lead Remediation Funds

    Get PDF
    Objective To examine the efficacy of direct mailing using four types of messaging on promoting the uptake of residential lead remediation (RLR) funds in Lancaster, PA, USA. Study design We designed a quasi-experiment to assess the effect of 4 RLR messages sent to households in Lancaster, PA by direct mail between September and December 2020: a brief flyer (F); a detailed brochure + the flyer (BF); a health infographic + the flyer (IF); and an application form + the flyer (AFF). Methods Mailers were sent to addresses in four census tracts; each census tract received a different message. Both English and Spanish versions were sent. The outcomes were the event rate defined as the number of phone call inquiries received, and the number of applications received. The association between type of messaging and household type (owner-vs renter-occupied) was assessed using a chi square test. Results The event rates for the renter-occupied households were lower than for owner-occupied households, regardless of treatment. The event rates for renter-occupied households in the F, BF, IF and AFF groups were 0.00%, 0.35%, 0.12% and 0.18% respectively compared to 0.93%, 0.45%, 0.86% and 1.32% for homeowners. More applications were received from homeowners, and the event rate of the owner-occupied households was significantly different from that of renter-occupied homes (p-value = 0.001). Conclusions Event rates and applications received were higher for owner-occupied households than they were for renter-occupied households. Direct mailing of RLR information is feasible especially if households at high risk for lead poisoning are targeted

    Statistical Analysis Plan for the Motor Neuron Disease Systematic Multi-Arm Adaptive Randomised Trial (MND-SMART)

    Get PDF
    Abstract Background MND-SMART is a platform, multi-arm, multi-stage, multi-centre, randomised controlled trial recruiting people with motor neuron disease. Initially, the treatments memantine and trazodone will each be compared against placebo, but other investigational treatments will be introduced into the trial later. The co-primary outcomes are the Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALS-FRS-R) functional outcome, which is assessed longitudinally, and overall survival. Methods Initially in MND-SMART, participants are randomised 1:1:1 via a minimisation algorithm to receive placebo or one of the two investigational treatments with up to 531 to be randomised in total. The comparisons between each research arm and placebo will be conducted in four stages, with the opportunity to cease further randomisations to poorly performing research arms at the end of stages 1 or 2. The final ALS-FRS-R analysis will be at the end of stage 3 and final survival analysis at the end of stage 4. The estimands for the co-primary outcomes are described in detail. The primary analysis of ALS-FRS-R at the end of stages 1 to 3 will involve fitting a normal linear mixed model to the data to calculate a mean difference in rate of ALS-FRS-R change between each research treatment and placebo. The pairwise type 1 error rate will be controlled, because each treatment comparison will generate its own distinct and separate interpretation. This publication is based on a formal statistical analysis plan document that was finalised and signed on 18 May 2022. Discussion In developing the statistical analysis plan, we had to carefully consider several issues such as multiple testing, estimand specification, interim analyses, and statistical analysis of the repeated measurements of ALS-FRS-R. This analysis plan attempts to balance multiple factors, including minimisation of bias, maximising power and precision, and deriving clinically interpretable summaries of treatment effects. Trial registration EudraCT Number, 2019–000099-41. Registered 2 October 2019, https://www.clinicaltrialsregister.eu/ctr-search/search?query=mnd-smart ClinicalTrials.gov, NCT04302870 . Registered 10 March 2020
    corecore