3,475 research outputs found

    IFRS digest : what U.S. practitioners and entities need to know now

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    https://egrove.olemiss.edu/aicpa_guides/1553/thumbnail.jp

    Oxygen-related traps in pentacene thin films: Energetic position and implications for transistor performance

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    We studied the influence of oxygen on the electronic trap states in a pentacene thin film. This was done by carrying out gated four-terminal measurements on thin-film transistors as a function of temperature and without ever exposing the samples to ambient air. Photooxidation of pentacene is shown to lead to a peak of trap states centered at 0.28 eV from the mobility edge, with trap densities of the order of 10(18) cm(-3). These trap states need to be occupied at first and cause a reduction in the number of free carriers, i.e. a consistent shift of the density of free holes as a function of gate voltage. Moreover, the exposure to oxygen reduces the mobility of the charge carriers above the mobility edge. We correlate the change of these transport parameters with the change of the essential device parameters, i.e. subthreshold performance and effective field-effect mobility. This study supports the assumption of a mobility edge for charge transport, and contributes to a detailed understanding of an important degradation mechanism of organic field-effect transistors. Deep traps in an organic field-effect transistor reduce the effective field-effect mobility by reducing the number of free carriers and their mobility above the mobility edge.Comment: 13 pages, 14 figures, to be published in Phys. Rev.

    Gender Differences Among Veterans Deployed in Support of the Wars in Afghanistan and Iraq

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    BACKGROUND: The changing scope of women’s roles in combat operations has led to growing interest in women’s deployment experiences and post-deployment adjustment. OBJECTIVES: To quantify the gender-specific frequency of deployment stressors, including sexual and non-sexual harassment, lack of social support and combat exposure. To quantify gender-specific post-deployment mental health conditions and associations between deployment stressors and posttraumatic stress disorder (PTSD), to inform the care of Veterans returning from the current conflicts. DESIGN: National mail survey of OEF/OIF Veterans randomly sampled within gender, with women oversampled. SETTING: The community. PARTICIPANTS: In total, 1,207 female and 1,137 male Veterans from a roster of all Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) Veterans. Response rate was 48.6 %. MAIN MEASURES: Deployment stressors (including combat and harassment stress), PTSD, depression, anxiety and alcohol use, all measured via self-report. KEY RESULTS: Women were more likely to report sexual harassment (OR = 8.7, 95% CI: 6.9, 11) but less likely to report combat (OR = 0 .62, 95 % CI: 0.50, 0.76). Women and men were equally likely to report symptoms consistent with probable PTSD (OR = 0 .87, 95 % CI: 0.70, 1.1) and symptomatic anxiety (OR  =  1.1, 9 5% CI: 0.86, 1.3). Women were more likely to report probable depression (OR = 1.3, 95 % CI: 1.1, 1.6) and less likely to report problematic alcohol use (OR  = 0 .59, 9 5% CI: 0.47, 0.72). With a five-point change in harassment stress, adjusted odds ratios for PTSD were 1.36 (95 % CI: 1.23, 1.52) for women and 1.38 (95 % CI: 1.19, 1.61) for men. The analogous associations between combat stress and PTSD were 1.31 (95 % CI: 1.24, 1.39) and 1.31 (95 % CI: 1.26, 1.36), respectively. CONCLUSIONS: Although there are important gender differences in deployment stressors—including women’s increased risk of interpersonal stressors—and post-deployment adjustment, there are also significant similarities. The post-deployment adjustment of our nation’s growing population of female Veterans seems comparable to that of our nation’s male Veterans

    A Monitoring Campaign for Luhman 16AB. I. Detection of Resolved Near-Infrared Spectroscopic Variability

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    [abbreviated] We report resolved near-infrared spectroscopic monitoring of the nearby L dwarf/T dwarf binary WISE J104915.57-531906.1AB (Luhman 16AB), as part of a broader campaign to characterize the spectral energy distribution and temporal variability of this system. A continuous 45-minute sequence of low-resolution IRTF/SpeX data spanning 0.8-2.4 micron were obtained, concurrent with combined-light optical photometry with ESO/TRAPPIST. Our spectral observations confirm the flux reversal of this binary, and we detect a wavelength-dependent decline in the relative spectral fluxes of the two components coincident with a decline in the combined-light optical brightness of the system over the course of the observation. These data are successfully modeled as a combination of brightness and color variability in the T0.5 Luhman 16B, consistent cloud variations; and no significant variability in L7.5 Luhman 16A. We estimate a peak-to-peak amplitude of 13.5% at 1.25 micron over the full lightcurve. Using a two-spot brightness temperature model, we infer an average cloud covering fraction of ~30-55% for Luhman 16B, varying by 15-30% over a rotation period. A Rhines scale interpretation for the size of the variable features explains an apparent correlation between period and amplitude for three highly variable T dwarfs, and predicts relatively fast winds (1-3 km/s) for Luhman 16B consistent with lightcurve evolution on an advective time scale (1-3 rotation periods). Our observations support the model of a patchy disruption of the mineral cloud layer as a universal feature of the L dwarf/T dwarf transition.Comment: 11 pages, 7 figures; accepted for publication in Astrophysical Journa

    Sexual Harassment Experiences and Harmful Alcohol Use in a Military Sample: Differences in Gender and the Mediating Role of Depression

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    The current investigation identified the genderspecific prevalence of sexual harassment and assault experienced during U.S. military service and the negative mental and physical health correlates of these experiences in a sample of former reservists. We surveyed a stratified random sample of 3,946 former reservists about their experiences during military service and their current health, including depression, posttraumatic stress disorder, somatic symptoms, and medical conditions. Prevalence estimates and confidence intervals of sexual harassment and assault were calculated. A series of logistic regressions identified associations with health symptoms and conditions. Both men and women had a substantial prevalence of military sexual harassment and assault. As expected, higher proportions of female reservists reported sexual harassment (60.0% vs 27.2% for males) and sexual assault (13.1% vs 1.6% for males). For both men and women, these experiences were associated with deleterious mental and physical health conditions, with sexual assault demonstrating stronger associations than other types of sexual harassment in most cases. This investigation is the first to document high instances of these experiences among reservists. These data provide further evidence that experiences of sexual harassment and assault during military service have significant implications for the healthcare needs of military veterans

    Source Zones, Recurrence Rates, and Time Histories for Earthquakes Affecting Kentucky

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    Time histories of hypothetical earthquakes, along with their peak-particle accelerations, and 0 and 5 percent damped response spectra are developed as guidelines for the seismic design of highway structures and bridges within Kentucky. The time histories are derived through the use of random vibration analyses, and take into consideration the probability of earthquakes from nearby seismic zones, the attenuation of ground motions with distance in the Central United States, and the possibility of a random event occurring outside of the generally recognized zones of seismicity in the area. Suggested peak-particle accelerations, time histories, and response spectra are intended for use at sites where the structure is assumed to be situated at the top of a bedrock foundation. For sites underlain by soils, and in particular for those sites underlain by poorly consolidated soils, it is recommended that site specific investigations be conducted by qualified professionals in order to determine the possibilities of frequency-dependent amplification (including resonance), damping, and soil failure when subjected to the suggested time histories. It should be noted that the seismic data is generated at the county seat and not at the county centroid

    Literacy under and over the desk: oppositions and heterogeneity

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    In this paper I argue that a dominant theme in New Literacy Studies research, the differences between literacy practices inside and outside school, has sometimes involved conflating ‘home literacy’ with private, unregulated ‘vernacular literacy’, and the use of an idealised abstract notion of schooled literacy to represent students’ actual everyday experience in the classroom. Drawing on linguistic ethnographic research in two British primary schools, I use examples of ‘unofficial’ and ‘official’ literacy activities from 10-11 year-olds to show that a wide range of different forms of literacy can be found in the classroom and I argue that the division between ‘vernacular’ and ‘schooled’ is not as clear-cut as is sometimes assumed. My analysis of children’s literacy activities suggests that, on the one hand, unofficial activities orientate towards and index official knowledges and the macro-level institutional order and, on the other hand, official activities are interpenetrated with informal practices and procedures. I also comment on some implications of using the New Literacy Studies ‘events and practices’ conceptual framework for understanding what is going on in classrooms

    Alendronate and Resistive Exercise Countermeasures Against Bed Rest-Induced Bone Loss: Biochemical Markers of Bone and Calcium Metabolism

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    Weightlessness-induced bone loss must be counteracted to ensure crew health during extendedduration space missions. Studies were conducted to assess two bone loss countermeasures in a ground-based model: horizontal bed rest. Following a 3-wk ambulatory adaptation period, male and female subjects (aged 21-56 y) completed a 17-wk bed rest protocol. Subjects were assigned to one of three treatments: alendronate (ALEN; 10 mg/d, n=6), resistive exercise (RE; 1.5 h/d, 6 d/wk, n=8), or control (CN; no countermeasure, n=8). Dietary intake was adjusted to maintain body weight. Endocrine and biochemical indices were measured in blood and urine using standard laboratory methods. All data reported are expressed as percent change from individual pre-bedrest data. Serum calcium changed little during bed rest, and tended to decrease (4-8%) in ALEN subjects. In RE subjects, bone alkaline phosphatase and osteocalcin were increased >65 and >30%, respectively, during bed rest, while these were unchanged or decreased in ALEN and CN subjects. Urinary calcium was increased 50% in CN subjects, but was unchanged or decreased in both ALEN and RE groups. Urinary n-telopeptide excretion was increased 40-50% in CN and RE subjects, but decreased 20% in ALEN subjects. Pyridinium crosslink and deoxypyridinoline excretion were increased 20-50% during bed rest. These data suggest that RE countermeasures are effective at increasing markers of bone formation in an analog of weightlessness, while ALEN reduces markers of bone resorption. Counteracting the bone loss of space flight may require both pharmacologic and exercise countermeasures

    Vacuum fluctuation force on a rigid Casimir cavity in a gravitational field

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    We discuss the possibility of verifying the equivalence principle for the zero-point energy of quantum electrodynamics, by evaluating the force, produced by vacuum fluctuations, acting on a rigid Casimir cavity in a weak gravitational field. The resulting force has opposite direction with respect to the gravitational acceleration; the order of magnitude for a multi-layer cavity configuration is derived and experimental feasibility is discussed, taking into account current technological resources.Comment: 13 pages, Latex. In the revised version, the presentation has been improve
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