3,066 research outputs found

    A Different Way Home: Resettlement Patterns in Northern Uganda

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    After decades of civil conflict leading to massive internal displacement of people, Northern Uganda is peaceful again and hundreds of thousands of displaced people have returned to the area. Using data from maps and satellite imagery, we examine the placement of homes before, during and after the conflict. Examining two study sites, one that experienced a great deal of violence over an extended period of time and one where the experience of violence was more limited, we observe the clustering of home placement in the post-conflict period. As resettlement occurs, there is also evidence of increased location of homes in close proximity to roads at the site with high levels of violence. This research informs what we presently know about the choices of returnees and has implications for service provision and the reclamation of property rights after conflict

    Many-Body Corrections to Charged-Current Neutrino Absorption Rates in Nuclear Matter

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    Including nucleon--nucleon correlations due to both Fermi statistics and nuclear forces, we have developed a general formalism for calculating the charged--current neutrino--nucleon absorption rates in nuclear matter. We find that at one half nuclear density many--body effects alone suppress the rates by a factor of two and that the suppression factors increase to ∼\sim5 at 4×10144\times10^{14} g cm−3^{-3}. The associated increase in the neutrino--matter mean--free--paths parallels that found for neutral--current interactions and opens up interesting possibilities in the context of the delayed supernova mechanism and protoneutron star cooling.Comment: 11 pages, APS REVTeX format, 1 PostScript figure, uuencoded compressed, and tarred, submitted to Physical Review Letter

    Project IICE: Inspiring Interdisciplinary Collaboration Experiences

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    Project IICE was a multi-disciplinary learning experience designed for students at Southern New Hampshire University. Students worked together in teams to communicate scientific data that was initially collected by an Introductory Botany class. Students in this course measured trees and recorded variables, including tree height, diameter, species, and canopy cover. They shared the data with students in freshman Statistics courses, who analyzed mathematically for trends. Finally, students in Graphic Design used the data to create visual representations and icons. Students collaborated in groups that were randomly assigned across all of the courses to include members of each discipline. During the process, each student was required to help others in the group understand the meaning of the data, through the collection, analysis, and design phases. In the final group poster presentations, students explained the meaning and value of each part. The emphasis was on their ability to communicate the significance of each part of the process, which helped them appreciate how the discipline they were working in contributed to the overall success of the project. The real-world data provided a context for students to experience working in cross-discipline teams, and sharpened communication skills

    Photochemical inactivation of chikungunya virus in human apheresis platelet components by amotosalen and UVA light

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    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that recently re-emerged in Africa and rapidly spread into countries of the Indian Ocean basin and South-East Asia. The mean viremic blood donation risk for CHIKV on La Réunion reached 1.5% at the height of the 2005–2006 outbreaks, highlighting the need for development of safety measures to prevent transfusion-transmitted infections. We describe successful inactivation of CHIKV in human platelets and plasma using photochemical treatment with amotosalen and long wavelength UVA illumination. Platelet components in additive solution and plasma units were inoculated with two different strains of high titer CHIKV stock (6.0–8.0 logs/mL), and then treated with amotosalen and exposure to 1.0–3.0 J/cm² UVA. Based on in vitro assays of infectious virus pre- and post-treatment to identify endpoint dilutions where virus was not detectable, mean viral titers could effectively be reduced by > 6.4 ± 0.6 log[subscript 10] TCID[subscript 50]/mL in platelets and ≥ 7.6 ± 1.4 logs in plasma, indicating this treatment has the capacity to prevent CHIKV transmission in human blood components collected from infected donors in or traveling from areas of CHIKV transmission

    Physical and in silico approaches identify DNA-PK in a Tax DNA-damage response interactome

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    <p>Abstract</p> <p>Background</p> <p>We have initiated an effort to exhaustively map interactions between HTLV-1 Tax and host cellular proteins. The resulting Tax interactome will have significant utility toward defining new and understanding known activities of this important viral protein. In addition, the completion of a full Tax interactome will also help shed light upon the functional consequences of these myriad Tax activities. The physical mapping process involved the affinity isolation of Tax complexes followed by sequence identification using tandem mass spectrometry. To date we have mapped 250 cellular components within this interactome. Here we present our approach to prioritizing these interactions via an <it>in silico </it>culling process.</p> <p>Results</p> <p>We first constructed an <it>in silico </it>Tax interactome comprised of 46 literature-confirmed protein-protein interactions. This number was then reduced to four Tax-interactions suspected to play a role in DNA damage response (Rad51, TOP1, Chk2, 53BP1). The first-neighbor and second-neighbor interactions of these four proteins were assembled from available human protein interaction databases. Through an analysis of betweenness and closeness centrality measures, and numbers of interactions, we ranked proteins in the first neighborhood. When this rank list was compared to the list of physical Tax-binding proteins, DNA-PK was the highest ranked protein common to both lists. An overlapping clustering of the Tax-specific second-neighborhood protein network showed DNA-PK to be one of three bridge proteins that link multiple clusters in the DNA damage response network.</p> <p>Conclusion</p> <p>The interaction of Tax with DNA-PK represents an important biological paradigm as suggested via consensus findings <it>in vivo </it>and <it>in silico</it>. We present this methodology as an approach to discovery and as a means of validating components of a consensus Tax interactome.</p

    Spectroscopy and Thermometry of Drumhead Modes in a Mesoscopic Trapped-Ion Crystal using Entanglement

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    We demonstrate spectroscopy and thermometry of individual motional modes in a mesoscopic 2D ion array using entanglement-induced decoherence as a method of transduction. Our system is a ∼\sim400 μ\mum-diameter planar crystal of several hundred 9^9Be+^+ ions exhibiting complex drumhead modes in the confining potential of a Penning trap. Exploiting precise control over the 9^9Be+^+ valence electron spins, we apply a homogeneous spin-dependent optical dipole force to excite arbitrary transverse modes with an effective wavelength approaching the interparticle spacing (∼\sim20 \nolinebreakμ\mum). Center-of-mass displacements below 1 nm are detected via entanglement of spin and motional degrees of freedom.Comment: 12 pages, 7 figures (includes Supplementary Material

    Methane Emissions from Process Equipment at Natural Gas Production Sites in the United States: Liquid Unloadings

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    Methane emissions from liquid unloadings were measured at 107 wells in natural gas production regions throughout the United States. Liquid unloadings clear wells of accumulated liquids to increase production, employing a variety of liquid lifting mechanisms. In this work, wells with and without plunger lifts were sampled. Most wells without plunger lifts unload less than 10 times per year with emissions averaging 21 000–35 000 scf methane (0.4–0.7 Mg) per event (95% confidence limits of 10 000–50 000 scf/event). For wells with plunger lifts, emissions averaged 1000–10 000 scf methane (0.02–0.2 Mg) per event (95% confidence limits of 500–12 000 scf/event). Some wells with plunger lifts are automatically triggered and unload thousands of times per year and these wells account for the majority of the emissions from all wells with liquid unloadings. If the data collected in this work are assumed to be representative of national populations, the data suggest that the central estimate of emissions from unloadings (270 Gg/yr, 95% confidence range of 190–400 Gg) are within a few percent of the emissions estimated in the EPA 2012 Greenhouse Gas National Emission Inventory (released in 2014), with emissions dominated by wells with high frequencies of unloadings

    Towards a Synthesis of Core-Collapse Supernova Theory

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    New insights into the mechanism and character of core--collapse supernova explosions are transforming the approach of theorists to their subject. The universal realization that the direct hydrodynamic mechanism does not work and that a variety of hydrodynamic instabilities can influence the viability of theoretical explosions has ushered in a new era in supernova modeling. In this paper, I discuss the important physical and technical issues that remain. I review the neutrino--driven mechanism, the possible roles of Rayleigh--Taylor instabilities, questions in neutrino transport, and the various observational constraints within which theorists must operate. However, a consensus has yet to be achieved among active workers concerning many important details and some essential phenomenology. This synopsis is meant to accomplish two things: 1) to focus attention on the interesting problems whose resolution will bring needed progress, and 2) to assess the current status of the theoretical art.Comment: Eighteen Pages, Elsevier Elsart LaTeX format, no figures, to appear in Nucl. Phys. A, as a contribution to the Festschrift in honor of Gerald E. Brown's 70'th Birthday. PostScript version available from [email protected]
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