6,317 research outputs found

    Electroweak Constraints on Warped Geometry in Five Dimensions and Beyond

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    Here we consider the tree level corrections to electroweak (EW) observables from standard model (SM) particles propagating in generic warped extra dimensions. The scale of these corrections is found to be dominated by three parameters, the Kaluza-Klein (KK) mass scale, the relative coupling of the KK gauge fields to the Higgs and the relative coupling of the KK gauge fields to fermion zero modes. It is found that 5D spaces that resolve the hierarchy problem through warping typically have large gauge-Higgs coupling. It is also found in D>5D>5 where the additional dimensions are warped the relative gauge-Higgs coupling scales as a function of the warp factor. If the warp factor of the additional spaces is contracting towards the IR brane, both the relative gauge-Higgs coupling and resulting EW corrections will be large. Conversely EW constraints could be reduced by finding a space where the additional dimension's warp factor is increasing towards the IR brane. We demonstrate that the Klebanov Strassler solution belongs to the former of these possibilities.Comment: 18 pages, 3 figures (references added) version to appear in JHE

    Morphine modulation of pain processing in medial and lateral pain pathways

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    <p>Abstract</p> <p>Background</p> <p>Despite the wide-spread use of morphine and related opioid agonists in clinic and their powerful analgesic effects, our understanding of the neural mechanisms underlying opioid analgesia at supraspinal levels is quite limited. The present study was designed to investigate the modulative effect of morphine on nociceptive processing in the medial and lateral pain pathways using a multiple single-unit recording technique. Pain evoked neuronal activities were simultaneously recorded from the primary somatosensory cortex (SI), ventral posterolateral thalamus (VPL), anterior cingulate cortex (ACC), and medial dorsal thalamus (MD) with eight-wire microelectrode arrays in awake rats.</p> <p>Results</p> <p>The results showed that the noxious heat evoked responses of single neurons in all of the four areas were depressed after systemic injection of 5 mg/kg morphine. The depressive effects of morphine included (i) decreasing the neuronal response magnitude; (ii) reducing the fraction of responding neurons, and (iii) shortening the response duration. In addition, the capability of cortical and thalamic neural ensembles to discriminate noxious from innocuous stimuli was decreased by morphine within both pain pathways. Meanwhile, morphine suppressed the pain-evoked changes in the information flow from medial to lateral pathway and from cortex to thalamus. These effects were completely blocked by pre-treatment with the opiate receptor antagonist naloxone.</p> <p>Conclusion</p> <p>These results suggest that morphine exerts analgesic effects through suppressing both sensory and affective dimensions of pain.</p

    Sommerfeld Enhancement from Multiple Mediators

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    We study the Sommerfeld enhancement experienced by a scattering object that couples to a tower of mediators. This can occur in, e.g., models of secluded dark matter when the mediator scale is generated naturally by hidden-sector confinement. Specializing to the case of a confining CFT, we show that off-resonant values of the enhancement can be increased by ~ 20% for cases of interest when (i) the (strongly-coupled) CFT admits a weakly-coupled dual description and (ii) the conformal symmetry holds up to the Planck scale. Larger enhancements are possible for lower UV scales due to an increase in the coupling strength of the tower.Comment: 17p, 2 figures; v2 JHEP version (inconsequential typo fixed, references added

    STRUCTURE, GATING, AND REGULATION OF THE CFTR ANION CHANNEL

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    The cystic fibrosis transmembrane conductance regulator (CFTR) belongs to the ATP binding cassette (ABC) transporter superfamily but functions as an anion channel crucial for salt and water transport across epithelial cells. CFTR dysfunction, because of mutations, causes cystic fibrosis (CF). The anion-selective pore of the CFTR protein is formed by its two transmembrane domains (TMDs) and regulated by its cytosolic domains: two nucleotide binding domains (NBDs) and a regulatory (R) domain. Channel activation requires phosphorylation of the R domain by cAMP-dependent protein kinase (PKA), and pore opening and closing (gating) of phosphorylated channels is driven by ATP binding and hydrolysis at the NBDs. This review summarizes available information on structure and mechanism of the CFTR protein, with a particular focus on atomic-level insight gained from recent cryo-electron microscopic structures and on the molecular mechanisms of channel gating and its regulation. The pharmacological mechanisms of small molecules targeting CFTR's ion channel function, aimed at treating patients suffering from CF and other diseases, are briefly discussed

    Dielectric and thermal relaxation in the energy landscape

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    We derive an energy landscape interpretation of dielectric relaxation times in undercooled liquids, comparing it to the traditional Debye and Gemant-DiMarzio-Bishop pictures. The interaction between different local structural rearrangements in the energy landscape explains qualitatively the recently observed splitting of the flow process into an initial and a final stage. The initial mechanical relaxation stage is attributed to hopping processes, the final thermal or structural relaxation stage to the decay of the local double-well potentials. The energy landscape concept provides an explanation for the equality of thermal and dielectric relaxation times. The equality itself is once more demonstrated on the basis of literature data for salol.Comment: 7 pages, 3 figures, 41 references, Workshop Disordered Systems, Molveno 2006, submitted to Philosophical Magazin

    Delayed nephrectomy has comparable long-term overall survival to immediate nephrectomy for cT1a renal cell carcinoma: A population-based analysis

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    Objectives: Early surgical resection remains the recommended treatment option for most small renal mass (≤4 cm). We examined the long-term overall survival (OS) of patients managed with delayed and immediate nephrectomy of cT1a renal cancer. / Patient and methods: We utilized the National Cancer Database (2005–2010) to identify 14,677 patients (immediate nephrectomy: 14,050 patients vs. late nephrectomy: 627 patients) aged 180 days from diagnosis, respectively. Inverse probability of treatment weighting–adjusted Kaplan-Meier curves and Cox proportional hazards regression analyses were used to compare OS of patients in the 2 treatment arms. Influence of patient age and Charlson Comorbidity Index on treatment effect was tested by interactions. Sensitivity analysis was performed to explore the outcome of delaying nephrectomy for >12 months. / Results: Median patient age was 55 years with a median follow-up of 82.5 months. Inverse probability of treatment weighting-adjusted Kaplan-Meier curves suggest no significant difference between treatment arms (immediate nephrectomy [180 days]) (Hazard ratio 0.96; 95% confidence interval 0.73–1.26; P = 0.77). This outcome was consistent between all patients regardless of age (P = 0.48). Sensitivity analysis reports no difference in OS even if nephrectomy was delayed by >12 months (P = 0.60). / Conclusions: We report that delayed and immediate nephrectomy for cT1a renal cell carcinoma confers comparable long-term OS. These findings suggest that a period of observation of between 6 and 12 months is safe to allow identification of renal masses, which will benefit from surgical resection

    How Geography Curricula Tackle Global Issues

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    The late Doreen Massey recently urged teachers to ‘take on the world’ (Massey, 2014). Though we may see the everyday world as a mosaic of different places, nations or regions defined by their boundaries, a global understanding brings different perspectives: of flows and networks and interdependencies. If we take this seriously - if we do take on the world - then young people need ideas in order to provide new ways of seeing and thinking. Geography in this sense is a disciplinary resource that provides access to a particular form of powerful knowledge: in short, the means to be able to ‘think geographically’. This chapter opens up and presents this argument. In the first part we provide a platform in the form of analysis of geography curricula from three countries, identifying both the potentials and the challenges that teachers face. Where is ‘the global’, we ask, and in what ways do formal curriculum documents inspire or constrain us from ‘taking on the world’? The second part seeks to develop a disciplinary view of the school subject, appealing to the sometimes beguiling notion of powerful knowledge. We end by introducing a capabilities approach to thinking about the school subject which demonstrates the responsibility that inevitably falls to well-prepared teachers to enact the curriculum

    Increased ventral striatal volume in college-aged binge drinkers

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    BACKGROUND Binge drinking is a serious public health issue associated with cognitive, physiological, and anatomical differences from healthy individuals. No studies, however, have reported subcortical grey matter differences in this population. To address this, we compared the grey matter volumes of college-age binge drinkers and healthy controls, focusing on the ventral striatum, hippocampus and amygdala. METHOD T1-weighted images of 19 binge drinkers and 19 healthy volunteers were analyzed using voxel-based morphometry. Structural data were also covaried with Alcohol Use Disorders Identification Test (AUDIT) scores. Cluster-extent threshold and small volume corrections were both used to analyze imaging data. RESULTS Binge drinkers had significantly larger ventral striatal grey matter volumes compared to controls. There were no between group differences in hippocampal or amygdalar volume. Ventral striatal, amygdalar, and hippocampal volumes were also negatively related to AUDIT scores across groups. CONCLUSIONS Our findings stand in contrast to the lower ventral striatal volume previously observed in more severe forms of alcohol use disorders, suggesting that college-age binge drinkers may represent a distinct population from those groups. These findings may instead represent early sequelae, compensatory effects of repeated binge and withdrawal, or an endophenotypic risk factor
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