Tax Indemnification and the Association Between Unrecognized Tax Benefit Reserves and Future Tax Cash Outflows

Tax indemnification transfers from a firm to an outside party the risk of potential cash settlements associated with uncertain tax positions taken in prior years. The current accounting treatment of tax indemnification under Accounting Standards Codification (ASC) 805 and the required disclosures for uncertain tax positions under ASC 740 provide little or no information regarding this risk transfer in the financial statements or notes. I examine merger and acquisition (M&A) contracts from 2008 through 2013 and find that tax indemnification is commonly present in M&A transactions. I then provide evidence that the association between current uncertain tax benefit reserves and future tax cash outflows is positive for firms that do not have indemnified tax positions but is not significant for firms that do have indemnified tax positions. Because the use of tax indemnification and tax insurance is becoming more common among U.S. firms and this trend is expected to continue, my results suggest that changes in the accounting treatment of uncertain tax positions and/or additional financial statement disclosures may be necessary to allow financial statement users to adequately assess the impact of uncertain tax positions when tax indemnification or tax insurance is present

Investigating the Extent of the Problem: Injury Epidemiology in Cross-Country and Track & Field

This dissertation aims to explore the problem of injuries in high school and collegiate cross-country and track and field by systematically reviewing and analyzing data from previous epidemiologic studies, comparing injury rates from a large dataset of collegiate track and field injuries, examining the psychology of injury reporting among adolescent runners, and identifying directions for future research in the field of sports injury epidemiology. Cross-country and track and field are popular modes of physical activity for many adolescents, but as with many sports, they have inherent injury risks that may lead participants to quit or increase their risk of conditions such as post-traumatic osteoarthritis. In order to understand the injury problem in these sports and measure the effectiveness of injury prevention strategies, it is important to have accurate measurements of injury risk. Differing methodologies used in previous research have resulted in large variances in observed injury risk among cross-country and track and field athletes. This dissertation includes a systematic review and met-analysis, which pools injury-related data from previous original research to provide overall estimates of injury risk, while highlighting inconsistencies and current gaps in epidemiological research within these populations. One current gap identified was the lack of epidemiological studies comparing injury patterns between diverse track and field disciplines such as sprinting, distance running, throwing, and jumping. The second study in this dissertation analyzed a large dataset of collegiate track and field injuries to estimate injury risk, while also examining the patterns and burden of injury across track and field disciplines. Another gap in sports injury research concerns the study of injury reporting behaviors. Previous epidemiological studies have cited injury underreporting as potentially skewing estimates of injury risk. Many of the injuries experienced by adolescent runners have a gradual onset and delays in their recognition and treatment can be detrimental to an athlete’s health. The third study in this dissertation surveyed a large sample of adolescent runners to examine important factors regarding their decision to report overuse injury symptoms

The Fundamentally Different Dynamics of Dust and Gas in Molecular Clouds

We study the behaviour of large dust grains in turbulent molecular clouds (MCs). In primarily neutral regions, dust grains move as aerodynamic particles, not necessarily with the gas. We therefore directly simulate, for the first time, the behaviour of aerodynamic grains in highly supersonic, magnetohydrodynamic turbulence typical of MCs. We show that, under these conditions, grains with sizes a ≳ 0.01 micron exhibit dramatic (exceeding factor ∼1000) fluctuations in the local dust-to-gas ratio (implying large small-scale variations in abundances, dust cooling rates, and dynamics). The dust can form highly filamentary structures (which would be observed in both dust emission and extinction), which can be much thinner than the characteristic width of gas filaments. Sometimes, the dust and gas filaments are not even in the same location. The ‘clumping factor’ ⟨n^2_(dust)⟩/⟨n_(dust)⟩^2 of the dust (critical for dust growth/coagulation/shattering) can reach ∼100, for grains in the ideal size range. The dust clustering is maximized around scales ∼ 0.2 pc (a/μm) (n_(gas)/100 cm^(−3))^(−1), and is ‘averaged out’ on larger scales. However, because the density varies widely in supersonic turbulence, the dynamic range of scales (and interesting grain sizes) for these fluctuations is much broader than in the subsonic case. Our results are applicable to MCs of essentially all sizes and densities, but we note how Lorentz forces and other physics (neglected here) may change them in some regimes. We discuss the potentially dramatic consequences for star formation, dust growth and destruction, and dust-based observations of MCs

Evaluation of semiconductor devices for Electric and Hybrid Vehicle (EHV) ac-drive applications, volume 1

The results of evaluation of power semiconductor devices for electric hybrid vehicle ac drive applications are summarized. Three types of power devices are evaluated in the effort: high power bipolar or Darlington transistors, power MOSFETs, and asymmetric silicon control rectifiers (ASCR). The Bipolar transistors, including discrete device and Darlington devices, range from 100 A to 400 A and from 400 V to 900 V. These devices are currently used as key switching elements inverters for ac motor drive applications. Power MOSFETs, on the other hand, are much smaller in current rating. For the 400 V device, the current rating is limited to 25 A. For the main drive of an electric vehicle, device paralleling is normally needed to achieve practical power level. For other electric vehicle (EV) related applications such as battery charger circuit, however, MOSFET is advantageous to other devices because of drive circuit simplicity and high frequency capability. Asymmetrical SCR is basically a SCR device and needs commutation circuit for turn off. However, the device poses several advantages, i.e., low conduction drop and low cost

Metal matrix composite analyzer (METCAN) user's manual, version 4.0

The Metal Matrix Composite Analyzer (METCAN) is a computer code developed at Lewis Research Center to simulate the high temperature nonlinear behavior of metal matrix composites. An updated version of the METCAN User's Manual is presented. The manual provides the user with a step by step outline of the procedure necessary to run METCAN. The preparation of the input file is demonstrated, and the output files are explained. The sample problems are presented to highlight various features of METCAN. An overview of the geometric conventions, micromechanical unit cell, and the nonlinear constitutive relationships is also provided

The dynamics of charged dust in magnetized molecular clouds

We study the dynamics of large, charged dust grains in turbulent giant molecular clouds (GMCs). Massive dust grains behave as aerodynamic particles in primarily neutral dense gas, and thus are able to produce dramatic small-scale fluctuations in the dust-to-gas ratio. Hopkins & Lee directly simulated the dynamics of neutral dust grains in supersonic magnetohydrodynamic turbulence, typical of GMCs, and showed that the dust-to-gas fluctuations can exceed factor ∼1000 on small scales, with important implications for star formation, stellar abundances and dust behaviour and growth. However, even in primarily neutral gas in GMCs, dust grains are negatively charged and Lorentz forces are non-negligible. Therefore, we extend our previous study by including the effects of Lorentz forces on charged grains (in addition to drag). For small-charged grains (sizes ≪ 0.1 μm), Lorentz forces suppress dust-to-gas ratio fluctuations, while for large grains (sizes ≳ 1 μm), Lorentz forces have essentially no effect, trends that are well explained with a simple theory of dust magnetization. In some special intermediate cases, Lorentz forces can enhance dust–gas segregation. Regardless, for the physically expected scaling of dust charge with grain size, we find the most important effects depend on grain size (via the drag equation) with Lorentz forces/charge as a second-order correction. We show that the dynamics we consider are determined by three dimensionless numbers in the limit of weak background magnetic fields: the turbulent Mach number, a dust drag parameter (proportional to grain size) and a dust Lorentz parameter (proportional to grain charge); these allow us to generalize our simulations to a wide range of conditions

On The Nature of Variations in the Measured Star Formation Efficiency of Molecular Clouds

Measurements of the star formation efficiency (SFE) of giant molecular clouds (GMCs) in the Milky Way generally show a large scatter, which could be intrinsic or observational. We use magnetohydrodynamic simulations of GMCs (including feedback) to forward-model the relationship between the true GMC SFE and observational proxies. We show that individual GMCs trace broad ranges of observed SFE throughout collapse, star formation, and disruption. Low measured SFEs (<<1%) are "real" but correspond to early stages, the true "per-freefall" SFE where most stars actually form can be much larger. Very high (>>10%) values are often artificially enhanced by rapid gas dispersal. Simulations including stellar feedback reproduce observed GMC-scale SFEs, but simulations without feedback produce 20x larger SFEs. Radiative feedback dominates among mechanisms simulated. An anticorrelation of SFE with cloud mass is shown to be an observational artifact. We also explore individual dense "clumps" within GMCs and show that (with feedback) their bulk properties agree well with observations. Predicted SFEs within the dense clumps are ~2x larger than observed, possibly indicating physics other than feedback from massive (main sequence) stars is needed to regulate their collapse.Comment: Fixed typo in the arXiv abstrac

The International Atomic Energy Agency global initiatives on nasopharyngeal cancer treatment

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