3,130 research outputs found

    “Is This Enough?” Digitizing Liz Lerman Dance Exchange Archives Media

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    Special Collections in Performing Arts (SCPA) at University of Maryland Libraries collects performing arts materials that preserve performance practice, instruction, and scholarship, including the full scope of audiovisual (AV) formats. The Liz Lerman Dance Exchange Archives at SCPA contains, among common print archival materials, a significant number of AV materials. This collection is examplar of the numerous challenges facing AV digitization and preservation projects in university libraries and archives, including determining metadata standards and best practices, describing at the appropriate level, handling technical and personnel issues, and working with vendors. In this article we outline the decisions made for this project, our ultimate workflow, lessons learned, and future plans

    New Measurement of the Direct 3α Decay from the 12C Hoyle State

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    Excited states in certain atomic nuclei possess an unusual structure, where the dominant degrees of freedom are those of α clusters rather than individual nucleons. It has been proposed that the diffuse 3α system of the 12C Hoyle state may behave like a Bose-Einstein condensate, where the α clusters maintain their bosonic identities. By measuring the decay of the Hoyle state into three α particles, we obtained an upper limit for the rare direct 3α decay branch of 0.047%. This value is now at a level comparable with theoretical predictions and could be a sensitive probe of the structure of this state

    Thick disk kinematics from RAVE and the solar motion

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    Radial velocity surveys such as the Radial Velocity Experiment (RAVE) provide us with measurements of hundreds of thousands of nearby stars most of which belong to the Galactic thin, thick disk or halo. Ideally, to study the Galactic disks (both thin and thick) one should make use of the multi-dimensional phase-space and the whole pattern of chemical abundances of their stellar populations. In this paper, with the aid of the RAVE Survey, we study the thin and thick disks of the Milky Way, focusing on the latter. We present a technique to disentangle the stellar content of the two disks based on the kinematics and other stellar parameters such as the surface gravity of the stars. Using the Padova Galaxy Model, we checked the ability of our method to correctly isolate the thick disk component from the Galaxy mixture of stellar populations. We introduce selection criteria in order to clean the observed radial velocities from the Galactic differential rotation and to take into account the partial sky coverage of RAVE. We developed a numerical technique to statistically disentangle thin and thick disks from their mixture. We deduce the components of the solar motion relative to the Local Standard of Rest (LSR) in the radial and vertical direction, the rotational lag of the thick disk component relative to the LSR, and the square root of the absolute value of the velocity dispersion tensor for the thick disk alone. The analysis of the thin disk is presented in another paper. We find good agreement with previous independent parameter determinations. In our analysis we used photometrically determined distances. In the Appendix we show that similar values can be found for the thick disk alone as derived in the main sections of our paper even without the knowledge of photometric distances.Comment: accepted on A&A, please see companion paper "THIN disk kinem...

    Differential effects of FODMAPs (Fermentable Oligo-, Di-, Mono-Saccharides and Polyols) on small and large intestinal contents in healthy subjects shown by MRI

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    OBJECTIVES: The objective of this study was to investigate whether ingestion of fructose and fructans (such as inulin) can exacerbate irritable bowel syndrome (IBS) symptoms. The aim was to better understand the origin of these symptoms by magnetic resonance imaging (MRI) of the gut. METHODS: A total of 16 healthy volunteers participated in a four-way, randomized, single-blind, crossover study in which they consumed 500 ml of water containing 40 g of either glucose, fructose, inulin, or a 1:1 mixture of 40 g glucose and 40 g fructose. MRI scans were performed hourly for 5 h, assessing the volume of gastric contents, small bowel water content (SBWC), and colonic gas. Breath hydrogen (H 2) was measured and symptoms recorded after each scan. RESULTS: Data are reported as mean (s.d.) (95 % CI) when normally distributed and median (range) when not. Fructose increased area under the curve (AUC) from 0 – 5 h of SBWC to 71 (23) l / min, significantly greater than for glucose at 36 (11 – 132) l / min ( P < 0.001), whereas AUC SBWC after inulin, 33 (17 – 106) l / min, was no different from that after glucose. Adding glucose to fructose decreased AUC SBWC to 55 (28) l / min ( P = 0.08) vs. fructose. Inulin substantially increased AUC colonic gas to 33 (20) l / min, signifi cantly greater than glucose and glucose + fructose (both P < 0.05). Breath H 2 rose more with inulin than with fructose. Glucose when combined with fructose signifi cantly reduced breath H 2 by 7,700 (3,121 – 12,300) p.p.m. / min relative to fructose alone ( P < 0.01, n = 13). CONCLUSIONS: Fructose but not inulin distends the small bowel with water. Adding glucose to fructose reduces the effect of fructose on SBWC and breath hydrogen. Inulin distends the colon with gas more than fructose, but causes few symptoms in healthy volunteers

    Chemical gradients in the Milky Way from the RAVE data

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    Aims. We aim at measuring the chemical gradients of the elements Mg, Al, Si, and Fe along the Galactic radius to provide new constraints on the chemical evolution models of the Galaxy and Galaxy models such as the Besancon model. Thanks to the large number of stars of our RAVE sample we can study how the gradients vary as function of the distance from the Galactic plane. Methods. We analysed three different samples selected from three independent datasets: a sample of 19 962 dwarf stars selected from the RAVE database, a sample of 10 616 dwarf stars selected from the Geneva-Copenhagen Survey (GCS) dataset, and a mock sample (equivalent to the RAVE sample) created by using the GALAXIA code, which is based on the Besancon model. The three samples were analysed by using the very same method for comparison purposes. We integrated the Galactic orbits and obtained the guiding radii (R-g) and the maximum distances from the Galactic plane reached by the stars along their orbits (Z(max)). We measured the chemical gradients as functions of R-g at different Z(max). Results. We found that the chemical gradients of the RAVE and GCS samples are negative and show consistent trends, although they are not equal: at Z(max) < 0.4 kpc and 4.5 < R-g(kpc) < 9.5, the iron gradient for the RAVE sample is d[Fe/H]/dR(g) = -0.065 dex kpc(-1), whereas for the GCS sample it is d[Fe/H]/dR(g) = -0.043 dex kpc(-1) with internal errors of +/-0.002 and +/-0.004 dex kpc(-1), respectively. The gradients of the RAVE and GCS samples become flatter at larger Z(max). Conversely, the mock sample has a positive iron gradient of d[Fe/H]/dR(g) = +0.053 +/- 0.003 dex kpc(-1) at Z(max) < 0.4 kpc and remains positive at any Z(max). These positive and unrealistic values originate from the lack of correlation between metallicity and tangential velocity in the Besancon model. In addition, the low metallicity and asymmetric drift of the thick disc causes a shift of the stars towards lower R-g and metallicity which, together with the thin-disc stars with a higher metallicity and R-g, generates a fictitious positive gradient of the full sample. The flatter gradient at larger Z(max) found in the RAVE and the GCS samples may therefore be due to the superposition of thin-and thick-disc stars, which mimicks a flatter or positive gradient. This does not exclude the possibility that the thick disc has no chemical gradient. The discrepancies between the observational samples and the mock sample can be reduced by i) decreasing the density; ii) decreasing the vertical velocity; and iii) increasing the metallicity of the thick disc in the Besancon model

    Regulation of ␣4␤2 Nicotinic Receptor Desensitization by Calcium and Protein Kinase C

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    ABSTRACT Neuronal nicotinic acetylcholine receptor (nAChR) desensitization is hypothesized to be a trigger for long-term changes in receptor number and function observed after chronic administration of nicotine at levels similar to those found in persons who use tobacco. Factors that regulate desensitization could potentially influence the outcome of long-lasting exposure to nicotine. The roles of Ca 2ϩ and protein kinase C (PKC) on desensitization of ␣4␤2 nAChRs expressed in Xenopus laevis oocytes were investigated. Nicotine-induced (300 nM; 30 min) desensitization of ␣4␤2 receptors in the presence of Ca 2ϩ developed in a biphasic manner with fast and slow exponential time constants of f ϭ 1.4 min (65% relative amplitude) and s ϭ 17 min, respectively. Recovery from desensitization was reasonably well described by a single exponential with rec ϭ 43 min. Recovery was largely eliminated after replacement of external Ca 2ϩ with Ba 2ϩ and slowed by calphostin C ( rec ϭ 48 min), an inhibitor of PKC. Conversely, the rate of recovery was enhanced by phorbol-12-myristate-13-acetate ( rec ϭ 14 min), a PKC activator, or by cyclosporin A (with rec ϭ 8 min), a phosphatase inhibitor. ␣4␤2 receptors containing a mutant ␣4 subunit that lacks a consensus PKC phosphorylation site exhibited little recovery from desensitization. Based on a twodesensitized-state cyclical model, it is proposed that after prolonged nicotine treatment, ␣4␤2 nAChRs accumulate in a &quot;deep&quot; desensitized state, from which recovery is very slow. We suggest that PKC-dependent phosphorylation of ␣4 subunits changes the rates governing the transitions from &quot;deep&quot; to &quot;shallow&quot; desensitized conformations and effectively increases the overall rate of recovery from desensitization. Longlasting dephosphorylation may underlie the &quot;permanent&quot; inactivation of ␣4␤2 receptors observed after chronic nicotine treatment
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