3,239 research outputs found

    The calibration of photographic and spectroscopic films: 1: A microscopic analysis of IIaO films. 2: The effects of agitation and soaking on IIaO films. 3: The effects of electric field on IIaO films. 4: The effects of X-ray radiation on IIaO films

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    The grain structure of the emulsion using both reflected and transmission light was examined along with the effects of soaking. The effect of a static charge by a Tesla-coil, and the effects of airport equipment, and dental X-rays on the film were also analyzed

    Balloon-borne radiometer measurement of Northern Hemisphere mid-latitude stratospheric HNO3 profiles spanning 12 years

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    Low-resolution atmospheric thermal emission spectra collected by balloon-borne radiometers over the time span of 1990–2002 are used to retrieve vertical profiles of HNO3, CFC-11 and CFC-12 volume mixing ratios between approximately 10 and 35 km altitude. All of the data analyzed have been collected from launches from a Northern Hemisphere mid-latitude site, during late summer, when stratospheric dynamic variability is at a minimum. The retrieval technique incorporates detailed forward modeling of the instrument and the radiative properties of the atmosphere, and obtains a best fit between modeled and measured spectra through a combination of onion-peeling and global optimization steps. The retrieved HNO3 profiles are consistent over the 12-year period, and are consistent with recent measurements by the Atmospheric Chemistry Experiment-Fourier transform spectrometer satellite instrument. This suggests that, to within the errors of the 1990 measurements, there has been no significant change in the HNO3 summer mid-latitude profile

    Banking market reaction to auctions of failed banks

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    In this study, we find that non-merger rival banks of failed banks from 2008 to 2013 experience substantial negative abnormal stock returns in the United States when failed banks are auctioned. Negative abnormal returns are related to contagion effects associated with an increased probability of their own failure and the information of these rival banks' opaque assets. We also find evidence that FDIC resolutions of these failed banks, similar to previous regulatory interventions, distort the market competition

    Secondary HIV Infection and Mitigation in Cure-Related HIV Trials During Analytical Treatment Interruptions

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    To the Editor—We are writing to express concerns regarding facts reported in 2 recent Journal of Infectious Diseases articles pertaining to the ANRSLIGHT study, conducted in 18 clinical sites in France between September 2013 and May 2015. Initially, we were delighted to see the authors implemented several inclusion criteria that we believe were likely to ensure safety of participants during the analytical treatment interruption (ATI) that occurred during the trial, for example a nadir of CD4+ T-cell count of ≥300 cells/mm3 and an initial CD4+ T-cell count of ≥600/mm3. However, other aspects are dismaying, including the detailed identifying information about the index participant and partner. We fear it is possible to identify both persons from the elaborate medical and nonmedical history provided. After contacting the study Principal Investigator, Dr Lelièvre, through a European colleague, it appears there were no consents to disclose this information. Thus, we feel strongly that it was inappropriate to include such comprehensive, potentially identifying details

    Entanglement over global distances via quantum repeaters with satellite links

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    We study entanglement creation over global distances based on a quantum repeater architecture that uses low-earth orbit satellites equipped with entangled photon sources, as well as ground stations equipped with quantum non-demolition detectors and quantum memories. We show that this approach allows entanglement creation at viable rates over distances that are inaccessible via direct transmission through optical fibers or even from very distant satellites.Comment: 5+3 pages, 3+2 figure

    Galaxy Merger Candidates in High-Redshift Cluster Environments

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    We compile a sample of spectroscopically- and photometrically-selected cluster galaxies from four high-redshift galaxy clusters (1.59<z<1.711.59 < z < 1.71) from the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS), and a comparison field sample selected from the UKIDSS Deep Survey. Using near-infrared imaging from the \textit{Hubble Space Telescope} we classify potential mergers involving massive (M∗≥3×1010M⊙M_* \geq 3\times 10^{10}\mathrm{M}_\odot) cluster members by eye, based on morphological properties such as tidal distortions, double nuclei, and projected near neighbors within 20 kpc. With a catalogue of 23 spectroscopic and 32 photometric massive cluster members across the four clusters and 65 spectroscopic and 26 photometric comparable field galaxies, we find that after taking into account contamination from interlopers, 11.0−5.6+7.0%11.0 ^{+7.0}_{-5.6}\% of the cluster members are involved in potential mergers, compared to 24.7−4.6+5.3%24.7^{+5.3}_{-4.6}\% of the field galaxies. We see no evidence of merger enhancement in the central cluster environment with respect to the field, suggesting that galaxy-galaxy merging is not a stronger source of galaxy evolution in cluster environments compared to the field at these redshifts.Comment: Accepted by Ap

    Derivation of tropospheric methane from TCCON CHâ‚„ and HF total column observations

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    The Total Carbon Column Observing Network (TCCON) is a global ground-based network of Fourier transform spectrometers that produce precise measurements of column-averaged dry-air mole fractions of atmospheric methane (CHâ‚„). Temporal variability in the total column of CHâ‚„ due to stratospheric dynamics obscures fluctuations and trends driven by tropospheric transport and local surface fluxes that are critical for understanding CHâ‚„ sources and sinks. We reduce the contribution of stratospheric variability from the total column average by subtracting an estimate of the stratospheric CHâ‚„ derived from simultaneous measurements of hydrogen fluoride (HF). HF provides a proxy for stratospheric CHâ‚„ because it is strongly correlated to CHâ‚„ in the stratosphere, has an accurately known tropospheric abundance (of zero), and is measured at most TCCON stations. The stratospheric partial column of CHâ‚„ is calculated as a function of the zonal and annual trends in the relationship between CHâ‚„ and HF in the stratosphere, which we determine from ACE-FTS satellite data. We also explicitly take into account the CHâ‚„ column averaging kernel to estimate the contribution of stratospheric CHâ‚„ to the total column. The resulting tropospheric CHâ‚„ columns are consistent with in situ aircraft measurements and augment existing observations in the troposphere

    The High Arctic in Extreme Winters: Vortex, Temperature, and MLS and ACE-FTS Trace Gas Evolution

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    The first three Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns at Eureka (80° N, 86° W) were during two extremes of Arctic winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was a record cold winter. New satellite measurements from ACE-Fourier Transform Spectrometer (ACE-FTS), Sounding of the Atmosphere using Broadband Emission Radiometry, and Aura Microwave Limb Sounder (MLS), with meteorological analyses and Eureka lidar and radiosonde temperatures, are used to detail the meteorology in these winters, to demonstrate its influence on transport and chemistry, and to provide a context for interpretation of campaign observations. During the 2004 and 2006 SSWs, the vortex broke down throughout the stratosphere, reformed quickly in the upper stratosphere, and remained weak in the middle and lower stratosphere. The stratopause reformed at very high altitude, above where it could be accurately represented in the meteorological analyses. The 2004 and 2006 Eureka campaigns were during the recovery from the SSWs, with the redeveloping vortex over Eureka. 2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March. The vortex was over Eureka at the start of the 2005 campaign, but moved away as it broke up. Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with Eureka radiosondes, and with lidar data up to 50–60 km. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex during the 2004 and 2006 Eureka campaigns compared to that in 2005
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