481 research outputs found

    Inadequacy of Scaling Arguments for Neutrino Cross Sections

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    The problem with the use of scaling arguments for simultaneous studies of different weak interaction processes is discussed. When different neutrino scattering cross sections involving quite different momentum transfers are being compared it difficult to define a meaningful single scaling factor to renormalize calculated cross sections. It has been suggested that the use of such scaling can be used to estimate high energy neutrino cross sections from low energy neutrino cross sections. This argument has lead to questions on the consistency of the magnitude of the LSND muon neutrino cross sections on 12^{12}C relative to other lower energy weak processes. The issue is revisited here and from inspection of the structure of the form factors involved it is seen that the problem arises from a poor description of the transition form factors at high momentum transfer. When wave functions that reproduce the transverse magnetic inelastic (e,e') scattering form factor for the 15.11 MeV state in 12^{12}C are used there is no longer a need for scaling the axial current, and the different weak interactions rates involving the T=1 1+^+ triplet in mass 12 are consistent with one another.Comment: 3 pages, 1 figur

    Spray pyrolysis of La0.6Sr0.4Co0.2Fe0.8O3-δ thin film cathodes

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    Spray pyrolysis has been used to prepare La0.6 Sr0.4Co0.2Fe0.8O3-δ thin film cathodes for solid oxide fuel cell (SOFC) applications. The films are polycrystalline with nano-meter sized grains and less than 1 μm in thickness. Deposition parameters for film deposition have been established. The ratio of deposition temperature to solvent boiling point is found to be the most important processing parameter that determines whether a crack free homogeneous and coherent film is obtained. The morphology can be tailored by the deposition parameters. Annealing at 650∘C for four hours in air results in coherent films of the desired perovskite phase. The films are potential cathodes for thin film micro-solid oxide fuel cell

    Spray pyrolysis of La0.6Sr0.4Co0.2Fe0.8O3-δ thin film cathodes

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    Spray pyrolysis has been used to prepare La0.6 Sr0.4Co0.2Fe0.8O3-δ thin film cathodes for solid oxide fuel cell (SOFC) applications. The films are polycrystalline with nano-meter sized grains and less than 1 μm in thickness. Deposition parameters for film deposition have been established. The ratio of deposition temperature to solvent boiling point is found to be the most important processing parameter that determines whether a crack free homogeneous and coherent film is obtained. The morphology can be tailored by the deposition parameters. Annealing at 650∘C for four hours in air results in coherent films of the desired perovskite phase. The films are potential cathodes for thin film micro-solid oxide fuel cell

    Why Every Librarian Should Know About Copyright: Creating Copyright Training Opportunities for Librarians at Your Institution

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    This book chapter addresses the importance of copyright training and education and aims to provide case studies and scenarios that demonstrate effective opportunities for engaging librarians in various library departments in issues of copyright. In particular, the chapter will explore the University of Central Florida’s (UCF) unique intersection between subject librarians and scholarly communication, as well as the Office of Scholarly Communication’s efforts to provide internal copyright training to librarians across the institution

    Humanities in the Open: The Challenges of Creating an Open Literature Anthology

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    This book chapter was a part of the publication, Open Pedagogy Approaches: Faculty, Library, and Student Collaborations. It highlights a case study from the University of Central Florida of creating an open literature anthology

    Spontane durale arteriovenöse Fistel am Sinus cavernosus: Demaskierung nach endoskopischer Nasennebenhöhlen-Operation

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    Zusammenfassung: Spontane arteriovenöse Fisteln können sich über längere Zeit symptomlos entwickeln, bevor sie mit Strömungsgeräuschen, Visusminderung, Exophthalmos und konjunktivaler Injektion symptomatisch werden. Wir stellen den seltenen Fall einer okkulten parainfektiösen duralen arteriovenösen Fistel vor. Diese demaskierte sich postoperativ durch akute Verschlechterung der venösen Drainage, möglicherweise aufgrund der intraoperativen Lagerung, positiver Beatmungsdrucke und Stauung durch die Nasentamponad

    Fluorescent Nanoparticles for the Measurement of Ion Concentration in Biological Systems

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    Tightly regulated ion homeostasis throughout the body is necessary for the prevention of such debilitating states as dehydration.1 In contrast, rapid ion fluxes at the cellular level are required for initiating action potentials in excitable cells.2 Sodium regulation plays an important role in both of these cases; however, no method currently exists for continuously monitoring sodium levels in vivo3 and intracellular sodium probes 4 do not provide similar detailed results as calcium probes. In an effort to fill both of these voids, fluorescent nanosensors have been developed that can monitor sodium concentrations in vitro and in vivo.5,6 These sensors are based on ion-selective optode technology and consist of plasticized polymeric particles in which sodium specific recognition elements, pH-sensitive fluorophores, and additives are embedded.7-9 Mechanistically, the sodium recognition element extracts sodium into the sensor. 10 This extraction causes the pH-sensitive fluorophore to release a hydrogen ion to maintain charge neutrality within the sensor which causes a change in fluorescence. The sodium sensors are reversible and selective for sodium over potassium even at high intracellular concentrations.6 They are approximately 120 nm in diameter and are coated with polyethylene glycol to impart biocompatibility. Using microinjection techniques, the sensors can be delivered into the cytoplasm of cells where they have been shown to monitor the temporal and spatial sodium dynamics of beating cardiac myocytes.11 Additionally, they have also tracked real-time changes in sodium concentrations in vivo when injected subcutaneously into mice.3 Herein, we explain in detail and demonstrate the methodology for fabricating fluorescent sodium nanosensors and briefly demonstrate the biological applications our lab uses the nanosensors for: the microinjection of the sensors into cells; and the subcutaneous injection of the sensors into mice

    Relativistic Effects in Electromagnetic Meson-Exchange Currents for One-Particle Emission Reactions

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    Following recent studies of non-relativistic reductions of the single-nucleon electromagnetic current operator, here we extend the treatment to include meson exchange current operators. We focus on one-particle emission electronuclear reactions. In contrast to the traditional scheme where approximations are made for the transferred momentum, transferred energy and momenta of the initial-state struck nucleons, we treat the problem exactly for the transferred energy and momentum, thus obtaining new current operators which retain important aspects of relativity not taken into account in the traditional non-relativistic reductions. We calculate the matrix elements of our current operators between the Fermi sphere and a particle-hole state for several choices of kinematics. We present a comparison between our results using approximate current operators and those obtained using the fully-relativistic operators, as well as with results obtained using the traditional non-relativistic current operators.Comment: LaTeX, 31 pages, 7 Postscript figures, to be published in Nucl. Phys.

    Functional approach to the non-mesonic decay of Lambda-hypernuclei

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    We present an evaluation of the non-mesonic decay widths for Lambda-hypernuclei (Lambda N --> NN, Lambda NN --> NNN) within the framework of the polarization propagator method. The full Lambda self-energy is evaluated microscopically in nuclear matter by using the functional approach, which supplies a theoretically well grounded approximation scheme for the classification of the relevant diagrams, according to the prescriptions of the bosonic loop expansion. We employ average Fermi momenta, suitably adapted to different mass number regions (medium-light, medium and heavy hypernuclei). Moreover, we study the dependence of the decay rates on the NN and Lambda-N short range correlations. With a proper choice of the parameters which control these correlations in the new approximation scheme, it is possible to reproduce the experimental decay widths for A > 10 hypernuclei.Comment: 25 pages, 8 figure

    Microsatellite analysis of raccoon (Procyon lotor) population structure across an extensive metropolitan landscape

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    Understanding population structure can lend insight into the spread of animal-borne disease, and the effects of anthropogenic land use on habitat. Raccoons are highly adaptive to human land development and can persist in a wide range of habitat types, making them ideal subjects for investigating the level of population structure in a highly fragmented area. A total of 323 raccoons were livetrapped from 7 locations encompassing 3 distinct habitat types (agriculture, urban forest preserves, and residential) across the Chicago metropolitan region (maximum distance between 2 sites was 128 km). Genetic analyses of 14 microsatellite loci indicate that although raccoon populations across the region share up to 50% of the allelic diversity, they segregated into at least 2 distinct subpopulations, dividing the Chicago metropolitan region into northern and southern groups with further structure occurring within these larger groups. Incorporating sample sites between the identified north- south groups may provide greater resolution as to where this split occurs. Although there is evidence of population structure between all sample sites, migrant analysis suggests there is enough gene flow to preserve genetic diversity throughout the populatio
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