1,367 research outputs found

    Access to undergraduate research experiences at a large research university

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    The American Physical Society recently released a statement calling on all university physics departments to provide or facilitate access to research experiences for all undergraduate students. In response, we investigated the current status of access to undergraduate research at University of Colorado Boulder (CU), a large research institution where the number of undergraduate physics majors outnumber faculty by roughly ten to one. We created and administered two surveys within CU's Physics Department: one probed undergraduate students' familiarity with, and participation in, research; the other probed faculty members' experiences as research mentors to undergraduates. We describe the development of these instruments, our results, and our corresponding evidence-based recommendations for improving local access to undergraduate research experiences. Reflecting on our work, we make several connections to an institutional change framework and note how other universities and colleges might adapt our process.Comment: 4 pages, 3 figures, 1 table; Submitted to 2015 PERC Proceeding

    Electrostatic image effects for counter-ions between charged planar walls

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    We study the effect of dielectric inhomogeneities on the interaction between two planparallel charged surfaces with oppositely charged mobile charges in between. The dielectric constant between the surfaces is assumed to be different from the dielectric constant of the two semiinfinite regions bounded by the surfaces, giving rise to electrostatic image interactions. We show that on the weak coupling level the image charge effects are generally small, making their mark only in the second order fluctuation term. However, in the strong coupling limit, the image effects are large and fundamental. They modify the interactions between the two surfaces in an essential way. Our calculations are particularly useful in the regime of parameters where computer simulations would be difficult and extremely time consuming due to the complicated nature of the long range image potentials.Comment: 21 pages, 8 figure

    A model approach to radioactive waste disposal at Sellafield UK

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    ABSTRACT One of the great environmental problems of our age is the safe disposal of radioactive waste for geological time periods. Britain is currently investigating a potential site for underground burial of waste, near the Sellafield nuclear plant. Future leakage of radionuclides depends greatly on subsurface water flows; these must be understood from the past, to predict hydrogeology 104-105 years into the future. We have taken information from the present-day, published by the government company Nirex, and used a finite-element steady-state fluid flow computer code to examine water flows in the subsurface. We find that flow directions at the planned Repository are persistently upwards, and that geologically significant flow rates could occur. Flow rates are particularly sensitive to uncertainties of rock permeability (conductivity) measurements made from site investigation boreholes. The hydrogeology at this site needs longer term investigation before a confident and credible prediction can be made

    Emergence of superfluid transport in a dynamical system of ultracold atoms

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    The dynamics of a Bose-Einstein condensate is studied theoretically in a combined periodic plus harmonic external potential. Different dynamical regimes of stable and unstable collective dipole and Bloch oscillations are analysed in terms of a quantum mechanical pendulum model. Nonlinear interactions are shown to counteract quantum-mechanical dephasing and lead to phase-coherent, superfluid transport

    Voids and Mn-rich inclusions in a (Ga,Mn)As ferromagnetic semiconductor investigated by transmission electron microscopy

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    Voids adjacent to both cubic (ZnS-type) and hexagonal (NiAs-type) Mn-rich nanocrystals are characterized using aberration-corrected transmission electron microscopy in annealed Ga0.995Mn0.005As magnetic semiconductor specimen grown by molecular beam epitaxy. Nano-beam electron diffraction measurements suggest that the nanocrystals exhibit deviations in lattice parameter from that of bulk MnAs. In situ annealing inside the electron microscope is used to study the nucleation, coalescence, and grain growth of individual nanocrystals. After annealing at 903 K, the magnetic transition temperature of the specimen likely to be dominated by the presence of cubic ferromagnetic nanocrystals

    Integrating Palliative Care Into the PICU: A Report From the Improving Palliative Care in the ICU Advisory Board

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    Objective: This review highlights benefits that patients, families and clinicians can expect to realize when palliative care is intentionally incorporated into the PICU. Data Sources: We searched the MEDLINE database from inception to January 2014 for English-language articles using the terms palliative care or end of life care or supportive care and pediatric intensive care. We also hand-searched reference lists and author files and relevant tools on the Center to Advance Palliative Care website. Study Selection: Two authors (physicians with experience in pediatric intensive care and palliative care) made final selections. Data Extraction: We critically reviewed the existing data and tools to identify strategies for incorporating palliative care into the PICU. Data Synthesis: The Improving Palliative Care in the ICU Advisory Board used data and experience to address key questions relating to: pain and symptom management, enhancing quality of life, communication and decision-making, length of stay, sites of care, and grief and bereavement. Conclusions: Palliative care should begin at the time of a potentially life-limiting diagnosis and continue throughout the disease trajectory, regardless of the expected outcome. Although the PICU is often used for short term postoperative stabilization, PICU clinicians also care for many chronically ill children with complex underlying conditions and others receiving intensive care for prolonged periods. Integrating palliative care delivery into the PICU is rapidly becoming the standard for high quality care of critically ill children. Interdisciplinary ICU staff can take advantage of the growing resources for continuing education in pediatric palliative care principles and interventions

    The Electronics and Data Acquisition System of the DarkSide Dark Matter Search

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    It is generally inferred from astronomical measurements that Dark Matter (DM) comprises approximately 27\% of the energy-density of the universe. If DM is a subatomic particle, a possible candidate is a Weakly Interacting Massive Particle (WIMP), and the DarkSide-50 (DS) experiment is a direct search for evidence of WIMP-nuclear collisions. DS is located underground at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, and consists of three active, embedded components; an outer water veto (CTF), a liquid scintillator veto (LSV), and a liquid argon (LAr) time projection chamber (TPC). This paper describes the data acquisition and electronic systems of the DS detectors, designed to detect the residual ionization from such collisions

    Methodology to resolve the transport equation with the discrete ordinates code TORT into the IPEN/MB-01 reactor

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    This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Computer Mathematics in 2014, available online: http://www.tandfonline.com/10.1080/00207160.2013.799668Resolution of the steady-state Neutron Transport Equation in a nuclear pool reactor is usually achieved by means of two different numerical methods: Monte Carlo (stochastic) and Discrete Ordinates (deterministic). The Discrete Ordinates method solves the Neutron Transport Equation for a set of selected directions, obtaining a set of directional equations and solutions for each equation which are the angular flux. In order to deal with the energy dependence, an energy multi-group approximation is commonly performed, obtaining a set of equations depending on the number of energy groups. In addition, spatial discretization is also required and the problem is solved by sweeping the geometry mesh. However, special cross-sections are required due to the energy and directional discretization, thus a methodology based on NJOY99 code capabilities has been used. Finally, in order to demonstrate the capability of this method, the 3D discrete ordinates code TORT has been applied to resolve the IPEN/MB-01 reactor.The authors wish to thank Departamento de Engenharia Nuclear da UFMG and Instituto de Pesquisas Energeticas e Nucleares for all data and support.Bernal García, Á.; Abarca Giménez, A.; Barrachina Celda, TM.; Miró Herrero, R. (2014). Methodology to resolve the transport equation with the discrete ordinates code TORT into the IPEN/MB-01 reactor. International Journal of Computer Mathematics. 91(1):113-123. doi:10.1080/00207160.2013.799668S113123911Rhoades, W. A., & Simpson, D. B. (1997). The TORT three-dimensional discrete ordinates neutron/photon transport code (TORT version 3). doi:10.2172/58226
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