4,917 research outputs found

    A self-powered pumping system for in situ extraction of particulate and dissolved materials from large volumes of seawater

    Get PDF
    A pumping system has been developed for the in situ extraction of particles and of dissolved constituents from large volumes of seawater. The assembly consists of a battery-powered submersible pump, filters, and chemisorptive cartridges; it is entirely self-contained and has been used successfully on ship's hydrographic wire to depths as great as 5800 m. The pump is designed to operate at a maximum pressure drop of 66 cm of Hg; flow rates have varied from 1.3 to 5.1 liters/min. We have sampled volumes as large as 758 liters, and the measured battery drain suggests that volumes several times this could be pumped at any depth. The system is being used to study a variety of artificial radionuclides, but modifications of the filter or chemisorbent units would make it useful in many other geochemical applications.Prepared for the U.S. Department of Energy under Contracts DE-AC02-76EV03563 and DE-AC02-81EV10694 and through Sandia Laboratories under Contracts 13-2562 and 16/3112

    Robust Weak-lensing Mass Calibration of Planck Galaxy Clusters

    Full text link
    In light of the tension in cosmological constraints reported by the Planck team between their SZ-selected cluster counts and Cosmic Microwave Background (CMB) temperature anisotropies, we compare the Planck cluster mass estimates with robust, weak-lensing mass measurements from the Weighing the Giants (WtG) project. For the 22 clusters in common between the Planck cosmology sample and WtG, we find an overall mass ratio of \left = 0.688 \pm 0.072. Extending the sample to clusters not used in the Planck cosmology analysis yields a consistent value of <MPlanck/MWtG>=0.698±0.062\left< M_{Planck}/M_{\rm WtG} \right> = 0.698 \pm 0.062 from 38 clusters in common. Identifying the weak-lensing masses as proxies for the true cluster mass (on average), these ratios are 1.6σ\sim 1.6\sigma lower than the default mass bias of 0.8 assumed in the Planck cluster analysis. Adopting the WtG weak-lensing-based mass calibration would substantially reduce the tension found between the Planck cluster count cosmology results and those from CMB temperature anisotropies, thereby dispensing of the need for "new physics" such as uncomfortably large neutrino masses (in the context of the measured Planck temperature anisotropies and other data). We also find modest evidence (at 95 per cent confidence) for a mass dependence of the calibration ratio and discuss its potential origin in light of systematic uncertainties in the temperature calibration of the X-ray measurements used to calibrate the Planck cluster masses. Our results exemplify the critical role that robust absolute mass calibration plays in cluster cosmology, and the invaluable role of accurate weak-lensing mass measurements in this regard.Comment: 5 pages, 2 figure

    Biliary Duct Granular Cell Tumor: A Rare But Surgically Curable Benign Tumor

    Get PDF
    Granulosa cell tumors are rare benign tumors which may be found throughout the body. Rare cases are isolated within the biliary tree. If completely resected, surgical excision is curative

    Effects of cardiovascular lifestyle change on lipoprotein subclass profiles defined by nuclear magnetic resonance spectroscopy

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Low-density lipoprotein (LDL) cholesterol lowering is a primary goal in clinical management of patients with cardiovascular disease, but traditional cholesterol levels may not accurately reflect the true atherogenicity of plasma lipid profiles. The size and concentration of lipoprotein particles, which transport cholesterol and triglycerides, may provide additional information for accurately assessing cardiovascular risk. This study evaluated changes in plasma lipoprotein profiles determined by nuclear magnetic resonance (NMR) spectroscopy in patients participating in a prospective, nonrandomized lifestyle modification program designed to reverse or stabilize progression of coronary artery disease (CAD) to improve our understanding of lipoprotein management in cardiac patients.</p> <p>Results</p> <p>The lifestyle intervention was effective in producing significant changes in lipoprotein subclasses that contribute to CAD risk. There was a clear beneficial effect on the total number of LDL particles (-8.3%, p < 0.05 compared to matched controls), small dense LDL particles (-9.5%, p < 0.05), and LDL particle size (+0.8%; p < 0.05). Likewise, participants showed significant improvement in traditional CAD risk factors such as body mass index (-9.9%, p < 0.01 compared to controls), total cholesterol (-5.5%, p < 0.05), physical fitness (+37.2%, p < 0.01), and future risk for CAD (-7.9%, p < 0.01). Men and women responded differently to the program for all clinically-relevant variables, with men deriving greater benefit in terms of lipoprotein atherogenicity. Plasma lipid and lipoprotein responses to the lifestyle change program were not confounded by lipid-lowering medications.</p> <p>Conclusion</p> <p>In <it>at risk </it>patients motivated to participate, an intensive lifestyle change program can effectively alter traditional CAD risk factors and plasma lipoprotein subclasses and may reduce risk for cardiovascular events. Improvements in lipoprotein subclasses are more evident in men compared to women.</p

    Planetary Candidates Observed by Kepler IV: Planet Sample from Q1-Q8 (22 Months)

    Get PDF
    We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2738 Kepler planet candidates distributed across 2017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ~40% of the sample with R_P ~ 1 R_⊕ and represent ~40% of the low equilibrium temperature (T_(eq) < 300 K) sample. We review the known biases in the current sample of Kepler planet candidates relevant to evaluating planet population statistics with the current Kepler planet candidate sample
    corecore