3,722 research outputs found

    Invasive fungal infections secondary to traumatic injury

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    Invasive fungal infection (IFI) is a rare but serious complication of traumatic injury. The purpose of this article is to review the epidemiology, natural history, mycology, risk factors, diagnosis, treatment, and outcomes associated with post-traumatic IFI in military and civilian populations. The epidemiology of post-traumatic IFI is poorly characterized, but incidence appears to be rising. Patients often suffer from severe injuries and require extensive medical interventions. Fungi belonging to the order Mucorales are responsible for most post-traumatic IFI in both civilian and military populations. Risk factors differ between these cohorts but include specific injury patterns and comorbidities. Diagnosis of post-traumatic IFI typically follows positive laboratory results in the appropriate clinical context. The gold standard of treatment is surgical debridement in addition to systemic antifungal therapy. Patients with post-traumatic IFI may be at greater risk of amputation, delays in wound healing, hospital complications, and death as compared to trauma patients who do not develop IFI. More research is needed to understand the factors surrounding the development and management of post-traumatic IFI to reduce the significant morbidity and mortality associated with this disease

    Why Don\u27t Students Major in Accounting?

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    William H. Bill Francisco is assistant professor of accounting, School of Accountancy, College of Business Administration, Georgia Southern University, Statesboro, GA 30460. Thomas G. Tom Noland is assistant professor of accounting, School of Accountancy, College of Business Administration, Georgia Southern University, Statesboro, GA 30460. J. Ann Kelly is temporary instructor of accounting, School of Accountancy, College of Business Administration, Georgia Southern University, Statesboro, GA 30460

    Modeling kicks from the merger of generic black-hole binaries

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    Recent numerical relativistic results demonstrate that the merger of comparable-mass spinning black holes has a maximum ``recoil kick'' of up to \sim 4000 \kms. However the scaling of these recoil velocities with mass ratio is poorly understood. We present new runs showing that the maximum possible kick perpendicular to the orbital plane does not scale as ∼η2\sim\eta^2 (where η\eta is the symmetric mass ratio), as previously proposed, but is more consistent with ∼η3\sim\eta^3, at least for systems with low orbital precession. We discuss the effect of this dependence on galactic ejection scenarios and retention of intermediate-mass black holes in globular clusters.Comment: 5 pages, 1 figure, 3 tables. Version published in Astrophys. J. Let

    Anatomy of the binary black hole recoil: A multipolar analysis

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    We present a multipolar analysis of the gravitational recoil computed in recent numerical simulations of binary black hole (BH) coalescence, for both unequal masses and non-zero, non-precessing spins. We show that multipole moments up to and including l=4 are sufficient to accurately reproduce the final recoil velocity (within ~2%) and that only a few dominant modes contribute significantly to it (within ~5%). We describe how the relative amplitudes, and more importantly, the relative phases, of these few modes control the way in which the recoil builds up throughout the inspiral, merger, and ringdown phases. We also find that the numerical results can be reproduced by an ``effective Newtonian'' formula for the multipole moments obtained by replacing the radial separation in the Newtonian formulae with an effective radius computed from the numerical data. Beyond the merger, the numerical results are reproduced by a superposition of three Kerr quasi-normal modes (QNMs). Analytic formulae, obtained by expressing the multipole moments in terms of the fundamental QNMs of a Kerr BH, are able to explain the onset and amount of ``anti-kick'' for each of the simulations. Lastly, we apply this multipolar analysis to help explain the remarkable difference between the amplitudes of planar and non-planar kicks for equal-mass spinning black holes.Comment: 28 pages, 20 figures, submitted to PRD; v2: minor revisions from referee repor

    A Conserved Chromatin Architecture Marks and Maintains the Restricted Germ Cell Lineage in Worms and Flies

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    AbstractIn C. elegans, mRNA production is initially repressed in the embryonic germline by a protein unique to C. elegans germ cells, PIE-1. PIE-1 is degraded upon the birth of the germ cell precursors, Z2 and Z3. We have identified a chromatin-based mechanism that succeeds PIE-1 repression in these cells. A subset of nucleosomal histone modifications, methylated lysine 4 on histone H3 (H3meK4) and acetylated lysine 8 on histone H4 (H4acetylK8), are globally lost and the DNA appears more condensed. This coincides with PIE-1 degradation and requires that germline identity is not disrupted. Drosophila pole cell chromatin also lacks H3meK4, indicating that a unique chromatin architecture is a conserved feature of embryonic germ cells. Regulation of the germline-specific chromatin architecture requires functional nanos activity in both organisms. These results indicate that genome-wide repression via a nanos-regulated, germ cell-specific chromatin organization is a conserved feature of germline maintenance during embryogenesis

    TRON 2.0 - The Experience

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    The goal of this senior project was to come up with a structural-engineering-related schematic design for a roller coaster to be installed in Disneyland called TRON 2.0: The Experience. This involved looking at both design processes that we had already learned through our curriculum as well as researching concepts that were previously foreign to us, namely the dynamic application of loads and the effects of fatigue stresses. A story was established based on the source material: the TRON movies produced by Walt Disney Studios. Thematic elements from the story were used as the basis for design implications that would become necessary as the process continued. These design implication influenced the design of the Ride System, Track Layout, and Ride Vehicle Design. These factors would end up influencing applicable loads, which would be utilized in the design of the Track Layout. The site was chosen to be constructed on Disneyland proper so that realistic site parameters and dimensions would give a sense of scale to the project and eliminate ambiguity. However, existing elements on the site would cause challenges for us to work around. Once the site was chosen, Queue and Show buildings were designated simple designs to tie back to story-driven implications and reinforce the standards set by the Walt Disney Imagineering process model. In addition, we gained more information such as crowd capacity to dictate further mechanical design and dynamic applications. The mechanical side of the process saw the development of a ride system used to propel the Ride Vehicles, all designed by the Mechanical Engineers on the project. The Ride Vehicle weights became relevant for the design of the track. A Track Layout was created and inputted into simulation software so that dynamic accelerations could be developed as new loading conditions for Track Design. Finally, all of the preceding elements of design were culminated into a schematic design of a roller coaster track making sure to account for subjects such as dynamic applications, torsion, and fatigue. All designs were replicated in modeling software to confirm constructability and viability of the resulting schematic design

    Integrated Ground Operations Demonstration Units Testing Plans and Status

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    Cryogenic propellant loading operations with their associated flight and ground systems are some of the most complex, critical activities in launch operations. Consequently, these systems and operations account for a sizeable portion of the life cycle costs of any launch program. NASA operations for handling cryogens in ground support equipment have not changed substantially in 50 years, despite advances in cryogenics, system health management and command and control technologies. This project was developed to mature, integrate and demonstrate advancement in the current state of the art in these areas using two distinct integrated ground operations demonstration units (GODU): GODU Integrated Refrigeration and Storage (IRAS) and GODU Autonomous Contro
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