115 research outputs found

    Justice Stevens and Securities Law

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    In this Article, we tell the overlooked story of Justice Stevens\u27s important role in Supreme Court securities law decisions. In Part I, where we briefly highlight Stevens\u27s career before his 1975 appointment to the Supreme Court, we observe that we can identify no evident interest in or connection to federal securities law or the securities industry, making his contributions all the more remarkable. The only foreshadowing of his prolific opinion-writing on the subject of securities law was his voluminous writing of opinions, in general, while serving on the Seventh Circuit Court of Appeals. This commitment to authoring opinions stemmed, in turn, from Stevens\u27s unforgettable experience as general counsel to a special commission that investigated bribery on the Illinois Supreme Court in the late 1960s, as Part I relates

    Optical modeling and polarization calibration for CMB measurements with ACTPol and Advanced ACTPol

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    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive upgrade to the Atacama Cosmology Telescope. Located at an elevation of 5190 m, ACTPol measures the Cosmic Microwave Background (CMB) temperature and polarization with arcminute-scale angular resolution. Calibration of the detector angles is a critical step in producing maps of the CMB polarization. Polarization angle offsets in the detector calibration can cause leakage in polarization from E to B modes and induce a spurious signal in the EB and TB cross correlations, which eliminates our ability to measure potential cosmological sources of EB and TB signals, such as cosmic birefringence. We present our optical modeling and measurements associated with calibrating the detector angles in ACTPol.Comment: 12 pages, 8 figures, conference proceedings submitted to Proceedings of SPIE; added reference in section 2 and merged repeated referenc

    Fertility Control Options for Management of Free-roaming Horse Populations

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    The management of free-roaming horses (Equus ferus) and burros (E. asinus) in the United States has been referred to as a “wicked problem” because, although there are population control options, societal values will ultimately determine what is acceptable and what is not. In the United States, free-roaming equids are managed by different types of organizations and agencies, and the landscapes that these animals inhabit vary widely in terms of access, size, topography, climate, natural resources, flora, and fauna. This landscape diversity, coupled with contemporary socioeconomic and political environments, means that adaptive management practices are needed to regulate these free-roaming populations. The Bureau of Land Management (BLM) currently manages free-roaming equids on 177 herd management areas in the United States by applying fertility control measures in situ and/or removing horses, which are either adopted by private individuals or sent to long-term holding facilities. The BLM off-range population currently includes \u3e50,000 animals and costs approximately $50 million USD per year to maintain; on-range equid numbers were estimated in March 2022 to be approximately 82,384. On-range populations can grow at 15–20% annually, and current estimates far exceed the designated appropriate management level of 26,715. To reduce population recruitment, managers need better information about effective, long-lasting or permanent fertility control measures. Because mares breed only once a year, fertility control studies take years to complete. Some contraceptive approaches have been studied for decades, and results from various trials can collectively inform future research directions and actions. Employing 1 or more fertility control tools in concert with removals offers the best potential for success. Active, iterative, cooperative, and thoughtful management practices can protect free-roaming horses while simultaneously protecting the habitat. Herein, we review contraceptive vaccines, intrauterine devices, and surgical sterilization options for controlling fertility of free-roaming horses. This review provides managers with a “fertility control toolbox” and guides future research

    Development of a Web-based Resident Profiling Tool to Support Training in Practice-based Learning and Improvement

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    Multiple factors are driving residency programs to explicitly address practice-based learning and improvement (PBLI), yet few information systems exist to facilitate such training. We developed, implemented, and evaluated a Web-based tool that provides Internal Medicine residents at the University of Virginia Health System with population-based reports about their ambulatory clinical experiences. Residents use Systems and Practice Analysis for Resident Competencies (SPARC) to identify potential areas for practice improvement. Thirty-three (65%) of 51 residents completed a survey assessing SPARC’s usefulness, with 94% agreeing that it was a useful educational tool. Twenty-six residents (51%) completed a before–after study indicating increased agreement (5-point Likert scale, with 5=strongly agree) with statements regarding confidence in ability to access population-based data about chronic disease management (mean [SD] 2.5 [1.2] vs. 4.5 [0.5], p < .001, sign test) and information comparing their practice style to that of their peers (2.2 [1.2] vs. 4.6 [0.5], p < .001)

    Mechanical design and development of TES bolometer detector arrays for the Advanced ACTPol experiment

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    The next generation Advanced ACTPol (AdvACT) experiment is currently underway and will consist of four Transition Edge Sensor (TES) bolometer arrays, with three operating together, totaling ~5800 detectors on the sky. Building on experience gained with the ACTPol detector arrays, AdvACT will utilize various new technologies, including 150mm detector wafers equipped with multichroic pixels, allowing for a more densely packed focal plane. Each set of detectors includes a feedhorn array of stacked silicon wafers which form a spline profile leading to each pixel. This is then followed by a waveguide interface plate, detector wafer, back short cavity plate, and backshort cap. Each array is housed in a custom designed structure manufactured from high purity copper and then gold plated. In addition to the detector array assembly, the array package also encloses cryogenic readout electronics. We present the full mechanical design of the AdvACT high frequency (HF) detector array package along with a detailed look at the detector array stack assemblies. This experiment will also make use of extensive hardware and software previously developed for ACT, which will be modified to incorporate the new AdvACT instruments. Therefore, we discuss the integration of all AdvACT arrays with pre-existing ACTPol infrastructure.Comment: 9 pages, 5 figures, SPIE Astronomical Telescopes and Instrumentation conference proceeding

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    The Atacama Cosmology Telescope: Mitigating the impact of extragalactic foregrounds for the DR6 CMB lensing analysis

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    We investigate the impact and mitigation of extragalactic foregrounds for the CMB lensing power spectrum analysis of Atacama Cosmology Telescope (ACT) data release 6 (DR6) data. Two independent microwave sky simulations are used to test a range of mitigation strategies. We demonstrate that finding and then subtracting point sources, finding and then subtracting models of clusters, and using a profile bias-hardened lensing estimator, together reduce the fractional biases to well below statistical uncertainties, with the inferred lensing amplitude, AlensA_{\mathrm{lens}}, biased by less than 0.2σ0.2\sigma. We also show that another method where a model for the cosmic infrared background (CIB) contribution is deprojected and high frequency data from Planck is included has similar performance. Other frequency-cleaned options do not perform as well, incurring either a large noise cost, or resulting in biased recovery of the lensing spectrum. In addition to these simulation-based tests, we also present null tests performed on the ACT DR6 data which test for sensitivity of our lensing spectrum estimation to differences in foreground levels between the two ACT frequencies used, while nulling the CMB lensing signal. These tests pass whether the nulling is performed at the map or bandpower level. The CIB-deprojected measurement performed on the DR6 data is consistent with our baseline measurement, implying contamination from the CIB is unlikely to significantly bias the DR6 lensing spectrum. This collection of tests gives confidence that the ACT DR6 lensing measurements and cosmological constraints presented in companion papers to this work are robust to extragalactic foregrounds.Comment: Companion paper to Qu et al and Madhavacheril et a

    The Atacama Cosmology Telescope: Modeling the Gas Thermodynamics in BOSS CMASS galaxies from Kinematic and Thermal Sunyaev-Zel'dovich Measurements

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    The thermal and kinematic Sunyaev-Zel'dovich effects (tSZ, kSZ) probe the thermodynamic properties of the circumgalactic and intracluster medium (CGM and ICM) of galaxies, groups, and clusters, since they are proportional, respectively, to the integrated electron pressure and momentum along the line-of-sight. We present constraints on the gas thermodynamics of CMASS galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS) using new measurements of the kSZ and tSZ signals obtained in a companion paper. Combining kSZ and tSZ measurements, we measure within our model the amplitude of energy injection ϵMc2\epsilon M_\star c^2, where MM_\star is the stellar mass, to be ϵ=(40±9)×106\epsilon=(40\pm9)\times10^{-6}, and the amplitude of the non-thermal pressure profile to be αNth<0.2\alpha_{\rm Nth}<0.2 (2σ\sigma), indicating that less than 20% of the total pressure within the virial radius is due to a non-thermal component. We estimate the effects of including baryons in the modeling of weak-lensing galaxy cross-correlation measurements using the best fit density profile from the kSZ measurement. Our estimate reduces the difference between the original theoretical model and the weak-lensing galaxy cross-correlation measurements in arXiv:1611.08606 by half, but does not fully reconcile it. Comparing the kSZ and tSZ measurements to cosmological simulations, we find that they under predict the CGM pressure and to a lesser extent the CGM density at larger radii. This suggests that the energy injected via feedback models in the simulations that we compared against does not sufficiently heat the gas at these radii. We do not find significant disagreement at smaller radii. These measurements provide novel tests of current and future simulations. This work demonstrates the power of joint, high signal-to-noise kSZ and tSZ observations, upon which future cross-correlation studies will improve.Comment: Accepted for publication in Physical Review D. Editors' Suggestion. New Fig. 1-2, Tab.
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