4,315 research outputs found

    A New Reliable Performance Analysis Template for Quantifying Action Variables in Elite Men’s Wheelchair Basketball

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    This study aimed to develop a valid and reliable performance analysis template for quantifying team action variables in elite men’s wheelchair basketball. First action variables and operational definitions were identified by the authors and verified by an expert panel of wheelchair basketball coaching staff in order to establish expert validity. A total of 109 action variable were then placed into 17 agreed Categorical Predictor Variable categories. The action variables were then used to develop a computerised performance analysis template for post-event analysis. Each possession (n=200) from an international men’s wheelchair basketball game was analysed by the first author on two occasions for assessment of intra-observer reliability and by a coach and a performance analyst for inter-observer reliability. Percentage error and Weighted Kappa coefficients were calculated to compare the levels of error and agreement for each action variable. Intra-observer reliability demonstrated perfect or almost perfect agreement (<K0.980) and low percentage error values (<1.50%) for the 109 action variables within the 17 categories. Inter-observer reliability demonstrated perfect or almost perfect agreement (<K0.974) and low percentage error values (<3.00%) for the 109 action variables within the 17 categories. The template should be used in future for obtaining valid and reliable data in elite men’s wheelchair basketball

    PPARÎŽ status and mismatch repair mediated neoplasia in the mouse intestine

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    BACKGROUND: Therapeutic regulation of PPARÎŽ activity using selective agonists has been proposed for various disorders. However, the consequences of altered peroxisome proliferator-activated receptor delta (PPARÎŽ) activity in the context of intestinal tumourigenesis remain somewhat unclear. Contradictory evidence suggesting PPARÎŽ either attenuates or potentiates intestinal neoplasia. To further investigate the PPARÎŽ dependency of intestinal tumourigenesis, we have analysed the consequences of PPARÎŽ deficiency upon intestinal neoplasia occurring in mice with impaired mismatch DNA repair. METHODS: Mice deficient for both PPARÎŽ and the mismatch repair gene Mlh1 were produced and the incidence and severity of intestinal neoplasia recorded. RESULTS: No significant differences between the control genotypes and the double mutant genotypes were recorded indicating that deficiency of PPARÎŽ does not modify impaired mismatch repair induced neoplasia. CONCLUSION: In contrast with the previously observed acceleration of intestinal neoplasia in the context of the Apc(Min/+ )mouse, PPARÎŽ deficiency does not alter the phenotype of mismatch repair deficiency. This data supports the notion that PPARÎŽ is not required for adenoma formation and indicate that any pro-tumourigenic effect of PPARÎŽ inactivation may be highly context dependent

    Selective pattern of motor system damage in gamma-synuclein transgenic mice mirrors the respective pathology in amyotrophic lateral sclerosis

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    AbstractAmyotrophic lateral sclerosis (ALS) is characterised by substantial loss of both upper and lower motor neuron function, with sensory and cognitive systems less affected. Though heritable forms of the disease have been described, the vast majority of cases are sporadic with poorly defined underlying pathogenic mechanisms. Here we demonstrate that the neurological pathology induced in transgenic mice by overexpression of Îł-synuclein, a protein not previously associated with ALS, recapitulates key features of the disease, namely selective damage and loss of discrete populations of upper and lower motor neurons and their axons, contrasted by limited effects upon the sensory system

    Autophagic and endo-lysosomal dysfunction in neurodegenerative disease

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    Due to their post-mitotic state, metabolic demands and often large polarised morphology, the function and survival of neurons is dependent on an efficient cellular waste clearance system both for generation of materials for metabolic processes and removal of toxic components. It is not surprising therefore that deficits in protein clearance can tip the balance between neuronal health and death. Here we discuss how autophagy and lysosome-mediated degradation pathways are disrupted in several neurological disorders. Both genetic and cell biological evidence show the diversity and complexity of vesicular clearance dysregulation in cells, and together may ultimately suggest a unified mechanism for neuronal demise in degenerative conditions. Causative and risk-associated mutations in Alzheimer’s disease, Frontotemporal Dementia, Amyotrophic Lateral Sclerosis, Parkinson’s disease, Huntington’s disease and others have given the field a unique mechanistic insight into protein clearance processes in neurons. Through their broad implication in neurodegenerative diseases, molecules involved in these genetic pathways, in particular those involved in autophagy, are emerging as appealing therapeutic targets for intervention in neurodegeneration

    Sorting of chromosomes by magnetic separation

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    Chromosomes were isolated from Chinese hamster x human hybrid cell lines containing four and nine human chromosomes. Human genomic DNA was biotinylated by nick translation and used to label the human chromosomes by in situ hybridization in suspension. Streptavidin was covalently coupled to the surface of magnetic beads and these were incubated with the hybridized chromosomes. The human chromosomes were bound to the magnetic beads through the strong biotin-streptavidin complex and then rapidly separated from nonlabeled Chinese hamster chromosomes by a simple permanent magnet. The hybridization was visualized by additional binding of avidin-FITC (fluorescein) to the unoccupied biotinylated human DNA bound to the human chromosomes. After magnetic separation, up to 98% of the individual chromosomes attached to magnetic beads were classified as human chromosomes by fluorescence microscopy

    Activated mutant NRasQ61K drives aberrant melanocyte signaling, survival, and invasiveness via a rac1-Dependent mechanism

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    Around a fifth of melanomas exhibit an activating mutation in the oncogene NRas that confers constitutive signaling to proliferation and promotes tumor initiation. NRas signals downstream of the major melanocyte tyrosine kinase receptor c-kit and activated NRas results in increased signaling via the extracellular signal–regulated kinase (ERK)/MAPK/ERK kinase/mitogen-activated protein kinase (MAPK) pathways to enhance proliferation. The Ras oncogene also activates signaling via the related Rho GTPase Rac1, which can mediate growth, survival, and motility signaling. We tested the effects of activated NRasQ61K on the proliferation, motility, and invasiveness of melanoblasts and melanocytes in the developing mouse and ex vivo explant culture as well as in a melanoma transplant model. We find an important role for Rac1 downstream of NRasQ61K in mediating dermal melanocyte survival in vivo in mouse, but surprisingly NRasQ61K does not appear to affect melanoblast motility or proliferation during mouse embryogenesis. We also show that genetic deletion or pharmacological inhibition of Rac1 in NRasQ61K induced melanoma suppresses tumor growth, lymph node spread, and tumor cell invasiveness, suggesting a potential value for Rac1 as a therapeutic target for activated NRas-driven tumor growth and invasiveness

    Power, Connected Coalitions, and Efficiency: Challenges to the Council of the European Union

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    This article is concerned with challenges to reforming the voting procedures of the Council of the European Union (EU). The next major waves of EU enlargement will cause the Union to increase to a membership of first twenty-one, and then twenty-six or possibly even more states. How does enlargement affect the Council's inherent "capacity to act" under the currently used qualified majority voting rule? It is demon strated here that the expected increase in EU membership will most likely induce a larger "status quo bias" as compared to the present situation in the Council if the crucial majority decision quota is not lowered. In addition, the article is responding to some criticism that has been applied against assessing the leverage of EU governments in one of the EU's most important institutions: the Council of the EU. By resorting to techniques that capture the influence of a priori coalitions on the one hand and "connected coalitions" among EU governments on the other—applying n- person cooperative game theory—the piece illustrates how the assessment of relative voting leverage in the framework of weighted voting systems may be extended and applied to situations in which the specific distribu tion of members' preferences is known. These calculations are again relevant in the face of the upcoming rounds of EU enlargement and projects for institutional reform.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68064/2/10.1177_019251219902000404.pd

    Searches for Gravitational Waves from Binary Neutron Stars: A Review

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    A new generation of observatories is looking for gravitational waves. These waves, emitted by highly relativistic systems, will open a new window for ob- servation of the cosmos when they are detected. Among the most promising sources of gravitational waves for these observatories are compact binaries in the final min- utes before coalescence. In this article, we review in brief interferometric searches for gravitational waves emitted by neutron star binaries, including the theory, instru- mentation and methods. No detections have been made to date. However, the best direct observational limits on coalescence rates have been set, and instrumentation and analysis methods continue to be refined toward the ultimate goal of defining the new field of gravitational wave astronomy.Comment: 30 pages, 5 Figures, to appear in "Short-Period Binary Stars: Observations, Analyses, and Results", Ed.s Eugene F. Milone, Denis A. Leahy, David W. Hobil

    Search for new fermions ("quirks") at the Fermilab Tevatron Collider

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    We report results of a search for particles with anomalously high ionization in events with a high transverse energy jet and large missing transverse energy in 2.42.4 fb−1^{-1} of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron ppˉp\bar{p} collider. Production of such particles (quirks) is expected in scenarios with extra QCD-like {\it SU(N)} sectors, and this study is the first dedicated search for such signatures. We find no evidence of a signal and set a lower mass limit of 107 ~GeV for the mass of a charged quirk with strong dynamics scale Λ\Lambda in the range from 10 keV to 1 MeV.Comment: submitted to Phys. Rev. Letter
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