2,402 research outputs found

    Coherent Vector Meson Photoproduction with Nuclear Breakup in Relativistic Heavy Ion Collisions

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    Relativistic heavy ions are copious sources of virtual photons. The large photon flux gives rise to a substantial photonuclear interaction probability at impact parameters where no hadronic interactions can occur. Multiple photonuclear interactions in a single collision are possible. In this letter, we use mutual Coulomb excitation of both nuclei as a tag for moderate impact parameter collisions. We calculate the cross section for coherent vector meson production accompanied by mutual excitation, and show that the median impact parameter is much smaller than for untagged production. The vector meson rapidity and transverse momentum distribution are very different from untagged exclusive vector meson production.Comment: 14 pages, including 4 figure

    The Self stepping into the shoes of the Other: Understanding and developing self-perceptions of empathy among prospective physical education teachers through a special school placement

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    Teachers who demonstrate a high degree of empathy are said to have more positive attitudes towards pupils with disabilities. Therefore, this article sought to explore the influence of a special school placement on prospective teachers’ self-perceptions of empathy. Thirty-two final year undergraduate students participated in focus group interviews and were selected because they aspired to be a physical education teacher and had attended a placement in a special school. Interview transcripts were analysed and the following themes constructed: Stepping into the shoes of the Other; Frustrated ‘for’ not ‘with’ pupils with disabilities; Empathy for planning inclusive lessons and ‘reading’ pupil body language; and Knowing when not to show empathy. All prospective teachers felt that: (a) they could empathise with pupils with disabilities; (b) situated learning experiences within the placement enabled them to reflect on the ways in which their empathy influences their teaching now and could continue to do so in the future; and (c) it was important that teachers demonstrated empathy. Thus, it is recommended that all prospective teachers gain some experience teaching in special schools. Our research also warns against teachers claiming the last, conclusive word about who children with disabilities are, what they think, how they feel and what they want, in myriad contexts and situations

    Motesanib inhibits Kit mutations associated with gastrointestinal stromal tumors

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    <p>Abstract</p> <p>Background</p> <p>Activating mutations in Kit receptor tyrosine kinase or the related platelet-derived growth factor receptor (PDGFR) play an important role in the pathogenesis of gastrointestinal stromal tumors (GIST).</p> <p>Methods</p> <p>This study investigated the activity of motesanib, an inhibitor of vascular endothelial growth factor receptors (VEGFR) 1, 2, and 3; PDGFR; and Kit, against primary activating Kit mutants and mutants associated with secondary resistance to imatinib. Single- and double-mutant isoforms of Kit were evaluated for their sensitivity to motesanib or imatinib in autophosphorylation assays and in Ba/F3 cell proliferation assays.</p> <p>Results</p> <p>Motesanib inhibited Kit autophosphorylation in CHO cell lines expressing primary activating mutations in exon 9 (AYins503-504, IC<sub>50 </sub>= 18 nM) and exon 11 (V560 D, IC<sub>50 </sub>= 5 nM; Δ552-559, IC<sub>50 </sub>= 1 nM). Motesanib also demonstrated activity against kinase domain mutations conferring imatinib resistance (V560D/V654A, IC<sub>50 </sub>= 77 nM; V560D/T670I, IC<sub>50 </sub>= 277 nM; Y823 D, IC<sub>50 </sub>= 64 nM) but failed to inhibit the imatinib-resistant D816V mutant (IC<sub>50 </sub>> 3000 nM). Motesanib suppressed the proliferation of Ba/F3 cells expressing Kit mutants with IC<sub>50 </sub>values in good agreement with those observed in the autophosphorylation assays.</p> <p>Conclusions</p> <p>In conclusion, our data suggest that motesanib possesses inhibitory activity against primary Kit mutations and some imatinib-resistant secondary mutations.</p

    Carnegie Supernova Project-II: Extending the Near-Infrared Hubble Diagram for Type Ia Supernovae to z0.1z\sim0.1

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    The Carnegie Supernova Project-II (CSP-II) was an NSF-funded, four-year program to obtain optical and near-infrared observations of a "Cosmology" sample of 100\sim100 Type Ia supernovae located in the smooth Hubble flow (0.03z0.100.03 \lesssim z \lesssim 0.10). Light curves were also obtained of a "Physics" sample composed of 90 nearby Type Ia supernovae at z0.04z \leq 0.04 selected for near-infrared spectroscopic time-series observations. The primary emphasis of the CSP-II is to use the combination of optical and near-infrared photometry to achieve a distance precision of better than 5%. In this paper, details of the supernova sample, the observational strategy, and the characteristics of the photometric data are provided. In a companion paper, the near-infrared spectroscopy component of the project is presented.Comment: 43 pages, 10 figures, accepted for publication in PAS

    Advancing the Selection of Neurodevelopmental Measures in Epidemiological Studies of Environmental Chemical Exposure and Health Effects

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    With research suggesting increasing incidence of pediatric neurodevelopmental disorders, questions regarding etiology continue to be raised. Neurodevelopmental function tests have been used in epidemiology studies to evaluate relationships between environmental chemical exposures and neurodevelopmental deficits. Limitations of currently used tests and difficulties with their interpretation have been described, but a comprehensive critical examination of tests commonly used in studies of environmental chemicals and pediatric neurodevelopmental disorders has not been conducted. We provide here a listing and critical evaluation of commonly used neurodevelopmental tests in studies exploring effects from chemical exposures and recommend measures that are not often used, but should be considered. We also discuss important considerations in selecting appropriate tests and provide a case study by reviewing the literature on polychlorinated biphenyls

    Predictive Power of Molecular Dynamics Receptor Structures in Virtual Screening

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    Molecular dynamics (MD) simulation is a well-established method for understanding protein dynamics. Conformations from unrestrained MD simulations have yet to be assessed for blind virtual screening (VS) by docking. This study presents a critical analysis of the predictive power of MD snapshots to this regard, evaluating two well-characterized systems of varying flexibility in ligand-bound and unbound configurations. Results from such VS predictions are discussed with respect to experimentally determined structures. In all cases, MD simulations provide snapshots that improve VS predictive power over known crystal structures, possibly due to sampling more relevant receptor conformations. Additionally, MD can move conformations previously not amenable to docking into the predictive range
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