17,093 research outputs found

    Access to recreational physical activities by car and bus : an assessment of socio-spatial inequalities in mainland Scotland

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    Obesity and other chronic conditions linked with low levels of physical activity (PA) are associated with deprivation. One reason for this could be that it is more difficult for low-income groups to access recreational PA facilities such as swimming pools and sports centres than high-income groups. In this paper, we explore the distribution of access to PA facilities by car and bus across mainland Scotland by income deprivation at datazone level. GIS car and bus networks were created to determine the number of PA facilities accessible within travel times of 10, 20 and 30 minutes. Multilevel negative binomial regression models were then used to investigate the distribution of the number of accessible facilities, adjusting for datazone population size and local authority. Access to PA facilities by car was significantly (p<0.01) higher for the most affluent quintile of area-based income deprivation than for most other quintiles in small towns and all other quintiles in rural areas. Accessibility by bus was significantly lower for the most affluent quintile than for other quintiles in urban areas and small towns, but not in rural areas. Overall, we found that the most disadvantaged groups were those without access to a car and living in the most affluent areas or in rural areas

    Anomalous structure in the single particle spectrum of the fractional quantum Hall effect

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    The two-dimensional electron system (2DES) is a unique laboratory for the physics of interacting particles. Application of a large magnetic field produces massively degenerate quantum levels known as Landau levels. Within a Landau level the kinetic energy of the electrons is suppressed, and electron-electron interactions set the only energy scale. Coulomb interactions break the degeneracy of the Landau levels and can cause the electrons to order into complex ground states. In the high energy single particle spectrum of this system, we observe salient and unexpected structure that extends across a wide range of Landau level filling fractions. The structure appears only when the 2DES is cooled to very low temperature, indicating that it arises from delicate ground state correlations. We characterize this structure by its evolution with changing electron density and applied magnetic field. We present two possible models for understanding these observations. Some of the energies of the features agree qualitatively with what might be expected for composite Fermions, which have proven effective for interpreting other experiments in this regime. At the same time, a simple model with electrons localized on ordered lattice sites also generates structure similar to those observed in the experiment. Neither of these models alone is sufficient to explain the observations across the entire range of densities measured. The discovery of this unexpected prominent structure in the single particle spectrum of an otherwise thoroughly studied system suggests that there exist core features of the 2DES that have yet to be understood.Comment: 15 pages, 10 figure

    Long-term trends in tropical cyclone tracks around Korea and Japan in late summer and early fall

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    This study investigates long-term trends in tropical cyclones (TCs) over the extratropical western North Pacific (WNP) over a period of 35 years (1982-2016). The area analyzed extended across 30-45 degrees N and 120-150 degrees E, including the regions of Korea and Japan that were seriously affected by TCs. The northward migration of TCs over the WNP to the mid-latitudes showed a sharp increase in early fall. In addition, the duration of TCs over the WNP that migrated northwards showed an increase, specifically in early to mid-September. Therefore, more recently, TC tracks have been observed to significantly extend into the mid-latitudes. The recent northward extension of TC tracks over the WNP in early fall was observed to be associated with changes in environmental conditions that were favorable for TC activities, including an increase in sea surface temperature (SST), decrease in vertical wind shear, expansion of subtropical highs, strong easterly steering winds, and an increase in relative vorticity. In contrast, northward migrations of TCs to Korea and Japan showed a decline in late August, because of the presence of unfavorable environmental conditions for TC activities. These changes in environmental conditions, such as SST and vertical wind shear, can be partially associated with the Pacific decadal oscillation

    Tumor-derived exosomes confer antigen-specific immunosuppression in a murine delayed-type hypersensitivity model

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    Exosomes are endosome-derived small membrane vesicles that are secreted by most cell types including tumor cells. Tumor-derived exosomes usually contain tumor antigens and have been used as a source of tumor antigens to stimulate anti-tumor immune responses. However, many reports also suggest that tumor-derived exosomes can facilitate tumor immune evasion through different mechanisms, most of which are antigen-independent. In the present study we used a mouse model of delayed-type hypersensitivity (DTH) and demonstrated that local administration of tumor-derived exosomes carrying the model antigen chicken ovalbumin (OVA) resulted in the suppression of DTH response in an antigen-specific manner. Analysis of exosome trafficking demonstrated that following local injection, tumor-derived exosomes were internalized by CD11c+ cells and transported to the draining LN. Exosome-mediated DTH suppression is associated with increased mRNA levels of TGF-β1 and IL-4 in the draining LN. The tumor-derived exosomes examined were also found to inhibit DC maturation. Taken together, our results suggest a role for tumor-derived exosomes in inducing tumor antigen-specific immunosuppression, possibly by modulating the function of APCs. © 2011 Yang et al

    A review of artificial intelligence in prostate cancer detection on imaging

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    A multitude of studies have explored the role of artificial intelligence (AI) in providing diagnostic support to radiologists, pathologists, and urologists in prostate cancer detection, risk-stratification, and management. This review provides a comprehensive overview of relevant literature regarding the use of AI models in (1) detecting prostate cancer on radiology images (magnetic resonance and ultrasound imaging), (2) detecting prostate cancer on histopathology images of prostate biopsy tissue, and (3) assisting in supporting tasks for prostate cancer detection (prostate gland segmentation, MRI-histopathology registration, MRI-ultrasound registration). We discuss both the potential of these AI models to assist in the clinical workflow of prostate cancer diagnosis, as well as the current limitations including variability in training data sets, algorithms, and evaluation criteria. We also discuss ongoing challenges and what is needed to bridge the gap between academic research on AI for prostate cancer and commercial solutions that improve routine clinical care

    Proteomic analysis of the Plasmodium male gamete reveals the key role for glycolysis in flagellar motility.

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    BACKGROUND: Gametogenesis and fertilization play crucial roles in malaria transmission. While male gametes are thought to be amongst the simplest eukaryotic cells and are proven targets of transmission blocking immunity, little is known about their molecular organization. For example, the pathway of energy metabolism that power motility, a feature that facilitates gamete encounter and fertilization, is unknown. METHODS: Plasmodium berghei microgametes were purified and analysed by whole-cell proteomic analysis for the first time. Data are available via ProteomeXchange with identifier PXD001163. RESULTS: 615 proteins were recovered, they included all male gamete proteins described thus far. Amongst them were the 11 enzymes of the glycolytic pathway. The hexose transporter was localized to the gamete plasma membrane and it was shown that microgamete motility can be suppressed effectively by inhibitors of this transporter and of the glycolytic pathway. CONCLUSIONS: This study describes the first whole-cell proteomic analysis of the malaria male gamete. It identifies glycolysis as the likely exclusive source of energy for flagellar beat, and provides new insights in original features of Plasmodium flagellar organization

    Measuring the Invisible Higgs Width at the 7 and 8 TeV LHC

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    The LHC is well on track toward the discovery or exclusion of a light Standard Model (SM)-like Higgs boson. Such a Higgs has a very small SM width and can easily have large branching fractions to physics beyond the SM, making Higgs decays an excellent opportunity to observe new physics. Decays into collider-invisible particles are particularly interesting as they are theoretically well motivated and relatively clean experimentally. In this work we estimate the potential of the 7 and 8 TeV LHC to observe an invisible Higgs branching fraction. We analyze three channels that can be used to directly study the invisible Higgs branching ratio at the 7 TeV LHC: an invisible Higgs produced in association with (i) a hard jet; (ii) a leptonic Z; and (iii) forward tagging jets. We find that the last channel, where the Higgs is produced via weak boson fusion, is the most sensitive, allowing branching fractions as small as 40% to be probed at 20 inverse fb for masses in the range between 120 and 170 GeV, including in particular the interesting region around 125 GeV. We provide an estimate of the 8 TeV LHC sensitivity to an invisibly-decaying Higgs produced via weak boson fusion and find that the reach is comparable to but not better than the reach at the 7 TeV LHC. We further estimate the discovery potential at the 8 TeV LHC for cases where the Higgs has substantial branching fractions to both visible and invisible final states.Comment: 23 pages, 7 figures. v2: version published in JHEP. 8 TeV analysis adde

    Proximity of Iron Pnictide Superconductors to a Quantum Tricritical Point

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    We determine the nature of the magnetic quantum critical point in the doped LaFeAsO using a set of constrained density functional calculations that provide ab initio coefficients for a Landau order parameter analysis. The system turns out to be remarkably close to a quantum tricritical point, where the nature of the phase transition changes from first to second order. We compare with the effective field theory and discuss the experimental consequences.Comment: 4 pages, 4 figure

    Magnetic properties of exactly solvable doubly decorated Ising-Heisenberg planar models

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    Applying the decoration-iteration procedure, we introduce a class of exactly solvable doubly decorated planar models consisting both of the Ising- and Heisenberg-type atoms. Exact solutions for the ground state, phase diagrams and basic physical quantities are derived and discussed. The detailed analysis of the relevant quantities suggests the existence of an interesting quantum antiferromagnetic phase in the system.Comment: 9 pages, 9 figures, submitted to Physical Review

    Structure and mechanism of human DNA polymerase η

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    The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase eta (Pol eta), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Pol eta at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Pol eta acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Pol eta orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assist translesion synthesis. On the basis of the structures, eight Pol eta missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Pol eta in replicating through D loop and DNA fragile sites
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