350 research outputs found

    Pulmonary arterial pressures, arterial blood-gas tensions, and serum biochemistry of beef calves born and raised at high altitude

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    Includes bibliographical references (page 8).High-altitude exposure is physiologically challenging. This is particularly true for animals native to low-altitude environments, such as British breeds of cattle. The objective of this study was to document the effect of high altitude on select physiological parameters of healthy beef calves (Bos taurus) born and raised on a high-altitude ranch typical of the Rocky Mountain region. Pulmonary arterial pressures, arterial blood-gas tensions, serum biochemistry, and hematocrit were evaluated. The calves studied were a composite of British (50%-75%) and Continental (25-50%) breeds born on one ranch at an altitude of 2410 m. Calves were sampled at an altitude of 2410 m when 1 month old and again at an altitude of 2730 m when 3 and 6 months old. Between 3 and 6 months of age, calves had access to grazing from 2730 m to approximately 3500 m above sea level. On each occasion, 16 to 50 calves were sampled. Only calves that remained healthy throughout all three testing periods were included in the dataset. Calves with the highest pulmonary arterial pressures at 1 month of age tended to have the highest pressures at 6 months of age (r = 0.43, P = 0.16, n = 12). Respiratory alkalosis was greatest at 6 months of age (pH 7.48 ± 0.06). Mean alveolar-arterial oxygen pressure gradients were 11.7and 11.6 mmHg at 3 and 6 months of age, indicating poor transfer of oxygen from the alveoli into the pulmonary blood. Median values for blood lactate ranged from 1.4 to 3.4 mmol/L indicating substantial anaerobic respiration at all ages. Mean hematocrits were ≤ 35.7%, only slightly higher than values obtained from age-matched calves at sea level. These results suggest that the provision of oxygen to the peripheral tissues of beef calves may be compromised at altitudes over 2410 m. This may have implications for diseases of the cardiopulmonary system.Published with support from the Colorado State University Libraries Open Access Research and Scholarship Fund

    TrES-3: A Nearby, Massive, Transiting Hot Jupiter in a 31-Hour Orbit

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    We describe the discovery of a massive transiting hot Jupiter with a very short orbital period (1.30619 d), which we name TrES-3. From spectroscopy of the host star GSC 03089-00929, we measure T_eff = 5720 +- 150 K, logg=4.6 +- 0.3, and vsini < 2 km/s, and derive a stellar mass of 0.90 +- 0.15 M_sun. We estimate a planetary mass of 1.92 +- 0.23 M_Jup, based on the sinusoidal variation of our high-precision radial velocity measurements. This variation has a period and phase consistent with our transit photometry. Our spectra show no evidence of line bisector variations that would indicate a blended eclipsing binary star. From detailed modeling of our B and z photometry of the 2.5%-deep transits, we determine a stellar radius 0.802 +- 0.046 R_sun and a planetary radius 1.295 +- 0.081 R_Jup. TrES-3 has one of the shortest orbital periods of the known transiting exoplanets, facilitating studies of orbital decay and mass loss due to evaporation, and making it an excellent target for future studies of infrared emission and reflected starlight.Comment: v1. 14 pages, 2 figures, 3 tables. Submitted to ApJL 27 April 2007. Accepted for publication in ApJL 14 May 200

    A Transiting Hot Jupiter Orbiting a Metal-Rich Star

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    We announce the discovery of Kepler-6b, a transiting hot Jupiter orbiting a star with unusually high metallicity, [Fe/H] = +0.34 +/- 0.04. The planet's mass is about 2/3 that of Jupiter, Mp = 0.67 Mj, and the radius is thirty percent larger than that of Jupiter, Rp = 1.32 Rj, resulting in a density of 0.35 g/cc, a fairly typical value for such a planet. The orbital period is P = 3.235 days. The host star is both more massive than the Sun, Mstar = 1.21 Msun, and larger than the Sun, Rstar = 1.39 Rsun.Comment: 12 pages, 2 figures, submitted to the Astrophysical Journal Letter

    Securing Our Economic Future

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    The American economy is in the midst of a wrenching crisis, one caused by the COVID-19 pandemic and aggravated further by a series of climate-driven natural disasters. While the economy has made some steps towards recovery, the pandemic has laid bare the reality that too many Americans are unable to meet many of their urgent and basic needs. At the same time, it has become painfully clear that American society is not equipped to deal with the risks emerging from our changing climate. This book is a contribution towards policy options for addressing these challenges. Although it was largely written before the pandemic crises beset our country, the analyses, diagnoses, and prescriptions contained within all shed new light on the underlying fragilities that have since been exposed. The volume is composed of nine commissioned chapters and is divided into three sections, covering the 'Economics of the American Middle Class'; the 'Geographic Disparities in Economic Opportunity'; and the 'Geopolitics of the Climate and Energy Challenge and the US Policy Response.' Part I focuses on the economic wellbeing of the American middle class and the chapters in this section evaluate the prevailing narrative of its decline. The chapters in part II investigate the large variation in income and economic opportunities across places, and include a specific policy proposal for emergency rental assistance. Part III is devoted to the global climate crisis. The chapters in this final section emphasize the mounting social and economic costs of inaction and discuss potential policy approaches for tackling the climate challenge

    The analgesic-like properties of the alpha7 nAChR silent agonist NS6740 is associated with non-conducting conformations of the receptor

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    The alpha 7 nicotinic acetylcholine receptor (nAChR) is a promising drug target for a number of neurological disorders including chronic pain and inflammatory diseases. Since alpha 7 can function as a ligand-gated ion channel, drug development initially focused on ligands that were selective activators of the alpha 7 ion channel. However, the best alpha 7 drugs for chronic pain and inflammation indications may not be ion channel activators but rather "silent agonists", which bind to the receptor but preferentially induce non-conducting states that modulate signal transduction in non-neuronal cells. One such compound is NS6740. We show that NS6740 selectively induces prolonged desensitization of alpha 7 nAChRs. There are two forms of alpha 7 desensitization that can be distinguished by their sensitivity to the positive allosteric modulators (PAMs). At high concentrations, NS6740 preferentially induces PAM-insensitive desensitization, which over the course of several minutes reverts to the sensitive form. NS6740 was tested in several pain models after in vivo administration in the mouse. Although it had no effects in acute thermal pain, NS6740 induced significant dose- and time-dependent antinociceptive activity in formalin- and acetic acid-induced nociceptive behaviors as well as in the chronic constrictive nerve injury (CCI) model for neuropathic pain. The antinociceptive activity of NS6740 in these models was alpha 7-dependent. In addition, NS6740 administration reversed pain-induced aversion, an important affective component of pain. The time and concentration dependence of the effects were consistent with NS6740 induction of PAM-insensitive non-conducting states, suggesting that signal transduction required for analgesia is accomplished by alpha 7 receptors in that conformation.VCU Massey Cancer Center (A-35337)United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute on Drug Abuse (NIDA) European Commission (DA032246)United States Department of Health & Human Services National Institutes of Health (NIH) - USA (GM57481)United States Department of Health & Human Services National Institutes of Health (NIH) - USA (DA027113)United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute of General Medical Sciences (NIGMS) (R01GM057481)United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute on Drug Abuse (NIDA) European Commission (R01DA032246)United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute on Drug Abuse (NIDA) European Commission (R01DA012610)United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute on Drug Abuse (NIDA) European Commission (R03DA027113

    Isolation Precautions for Visitors

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    Transmission of organisms within the hospital setting has become a topic of major concern not only for patients and healthcare facilities but also for government agencies and the general public. This increased awareness has occurred in part due to the spread of organisms that have limited treatment options, such as carbapenem-resistant Enterobacteriaceae (CRE), as well as the heightened recognition that many hospital-associated infections (HAIs) are preventable. A large body of literature shows that horizontal transmission of multidrug-resistant organisms involves the hands, and potentially the attire, of healthcare workers (HCWs). This evidence provides the rationale for the use of standard and contact isolation precautions among HCWs. However, the health risks to visitors and the role of visitors in the horizontal transmission of pathogens within acute care hospitals is not as clearly defined. Consequently, uncertainty remains regarding which precautions visitors should take when interacting with patients placed on isolation precautions. Frequent arguments against the use of isolation precautions among visitors include lack of visitor movement between patient rooms, the difficulty of educating visitors, and the difficulty of enforcing compliance with isolation practices

    Slowing and cooling molecules and neutral atoms by time-varying electric field gradients

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    A method of slowing, accelerating, cooling, and bunching molecules and neutral atoms using time-varying electric field gradients is demonstrated with cesium atoms in a fountain. The effects are measured and found to be in agreement with calculation. Time-varying electric field gradient slowing and cooling is applicable to atoms that have large dipole polarizabilities, including atoms that are not amenable to laser slowing and cooling, to Rydberg atoms, and to molecules, especially polar molecules with large electric dipole moments. The possible applications of this method include slowing and cooling thermal beams of atoms and molecules, launching cold atoms from a trap into a fountain, and measuring atomic dipole polarizabilities.Comment: 13 pages, 10 figures. Scheduled for publication in Nov. 1 Phys. Rev.

    Cost-effectiveness of Implementing Low-Tidal Volume Ventilation in Patients With Acute Lung Injury

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    Background: Despite widespread guidelines recommending the use of lung-protective ventilation (LPV) in patients with acute lung injury (ALI), many patients do not receive this lifesaving therapy. We sought to estimate the incremental clinical and economic outcomes associated with LPV and determined the maximum cost of a hypothetical intervention to improve adherence with LPV that remained cost-effective. Methods: Adopting a societal perspective, we developed a theoretical decision model to determine the cost-effectiveness of LPV compared to non-LPV care. Model inputs were derived from the literature and a large population-based cohort of patients with ALI. Cost-effectiveness was determined as the cost per life saved and the cost per quality-adjusted life-years (QALYs) gained. Results: Application of LPV resulted in an increase in QALYs gained by 15% (4.21 years for non-LPV vs 4.83 years for LPV), and an increase in lifetime costs of 7,233perpatientwithALI(7,233 per patient with ALI (99,588 for non-LPV vs 106,821forLPV).TheincrementalcosteffectivenessratiosforLPVwere106,821 for LPV). The incremental cost-effectiveness ratios for LPV were 22,566 per life saved at hospital discharge and 11,690perQALYgained.Themaximum,costeffective,perpatientinvestmentinahypotheticalprogramtoimproveLPVadherencefrom50to9011,690 per QALY gained. The maximum, cost-effective, per patient investment in a hypothetical program to improve LPV adherence from 50 to 90% was 9,482. Results were robust to a wide range of economic and patient parameter assumptions. Conclusions: Even a costly intervention to improve adherence with low-tidal volume ventilation in patients with ALI reduces death and is cost-effective by current societal standards.NIH F32HL090220.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84154/1/Cooke - CEA LPV.pd

    Weak Lensing with SDSS Commissioning Data: The Galaxy-Mass Correlation Function To 1/h Mpc

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    (abridged) We present measurements of galaxy-galaxy lensing from early commissioning imaging data from the Sloan Digital Sky Survey (SDSS). We measure a mean tangential shear around a stacked sample of foreground galaxies in three bandpasses out to angular radii of 600'', detecting the shear signal at very high statistical significance. The shear profile is well described by a power-law. A variety of rigorous tests demonstrate the reality of the gravitational lensing signal and confirm the uncertainty estimates. We interpret our results by modeling the mass distributions of the foreground galaxies as approximately isothermal spheres characterized by a velocity dispersion and a truncation radius. The velocity dispersion is constrained to be 150-190 km/s at 95% confidence (145-195 km/s including systematic uncertainties), consistent with previous determinations but with smaller error bars. Our detection of shear at large angular radii sets a 95% confidence lower limit s>140s>140^{\prime\prime}, corresponding to a physical radius of 260h1260h^{-1} kpc, implying that galaxy halos extend to very large radii. However, it is likely that this is being biased high by diffuse matter in the halos of groups and clusters. We also present a preliminary determination of the galaxy-mass correlation function finding a correlation length similar to the galaxy autocorrelation function and consistency with a low matter density universe with modest bias. The full SDSS will cover an area 44 times larger and provide spectroscopic redshifts for the foreground galaxies, making it possible to greatly improve the precision of these constraints, measure additional parameters such as halo shape, and measure the properties of dark matter halos separately for many different classes of galaxies.Comment: 28 pages, 11 figures, submitted to A

    Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler

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    We report the distribution of planets as a function of planet radius (R_p), orbital period (P), and stellar effective temperature (Teff) for P < 50 day orbits around GK stars. These results are based on the 1,235 planets (formally "planet candidates") from the Kepler mission that include a nearly complete set of detected planets as small as 2 Earth radii (Re). For each of the 156,000 target stars we assess the detectability of planets as a function of R_p and P. We also correct for the geometric probability of transit, R*/a. We consider first stars within the "solar subset" having Teff = 4100-6100 K, logg = 4.0-4.9, and Kepler magnitude Kp < 15 mag. We include only those stars having noise low enough to permit detection of planets down to 2 Re. We count planets in small domains of R_p and P and divide by the included target stars to calculate planet occurrence in each domain. Occurrence of planets varies by more than three orders of magnitude and increases substantially down to the smallest radius (2 Re) and out to the longest orbital period (50 days, ~0.25 AU) in our study. For P < 50 days, the radius distribution is given by a power law, df/dlogR= k R^\alpha. This rapid increase in planet occurrence with decreasing planet size agrees with core-accretion, but disagrees with population synthesis models. We fit occurrence as a function of P to a power law model with an exponential cutoff below a critical period P_0. For smaller planets, P_0 has larger values, suggesting that the "parking distance" for migrating planets moves outward with decreasing planet size. We also measured planet occurrence over Teff = 3600-7100 K, spanning M0 to F2 dwarfs. The occurrence of 2-4 Re planets in the Kepler field increases with decreasing Teff, making these small planets seven times more abundant around cool stars than the hottest stars in our sample. [abridged]Comment: Submitted to ApJ, 22 pages, 10 figure
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