1,455 research outputs found

    Effect of zinc intake on serum/plasma zinc status in infants: A meta-analysis

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    A systematic review and meta-analysis of available RCTs was conducted to evaluate the effect of zinc (Zn) intake on serum/plasma Zn status in infants. Out of 5500 studies identified through electronic searches and reference lists, 9 RCTs were selected after applying the exclusion/inclusion criteria. The influence of zinc intake on serum/plasma Zn concentration was considered in the overall meta-analysis. Other variables were also taken into account as possible effect modifiers: doses of zinc intake, intervention duration, nutritional status and risk of bias. From each selected study, final measures of serum/plasma Zn were assessed. RESULTS: The pooled β of status was 0.09 (95%CI 0.06 to 0.12). However, a substantial heterogeneity was present in the analyses (I2=95%; p=0.00001). When we performed a meta-regression, the effect of Zn intake on serum/plasma Zn status changed depending on the duration of the intervention, the dose of supplementation and the nutritional situation (p ANCOVA= 0.005; 20 weeks). A positive effect was seen also when doses ranged from 8.1 to 12 mg/day. In all cases, the pooled β showed high evidence of heterogeneity. CONCLUSION: Zinc supplementation increases serum/plasma Zn status in infants, although high evidence of heterogeneity was found. Further standardized research is urgently needed to reach evidence-based conclusions to clarify the role of zinc supplementation upon infant serum/plasma Zn status, particularly in Europe

    Quantum black hole entropy and Newton constant renormalization

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    We discuss the status of the black hole entropy formula SBH=AH/4GS_{\rm BH} = A_H /4G in low energy effective field theory. The low energy expansion of the black hole entropy is studied in a non-equilibrium situation: the semiclassical decay of hot flat space by black hole nucleation. In this context the entropy can be defined as an enhancement factor in the semiclassical decay rate, which is dominated by a sphaleron-like saddle point. We find that all perturbative divergences appearing in Euclidean calculations of the entropy can be renormalized in low energy couplings. We also discuss some formal aspects of the relation between the Euclidean and Hamiltonian approaches to the one loop corrections to black hole entropy and geometric entropy, and we emphasize the virtues of the use of covariant regularization prescriptions. In fact, the definition of black hole entropy in terms of decay rates {\it requires} the use of covariant measures and accordingly, covariant regularizations in path integrals. Finally, we speculate on the possibility that low energy effective field theory could be sufficient to understand the microscopic degrees of freedom underlying black hole entropy. We propose a qualitative physical picture in which black hole entropy refers to a space of quasi-coherent states of infalling matter, together with its gravitational field. We stress that this scenario might provide a low energy explanation of both the black hole entropy and the information puzzle.Comment: 24 pages, LaTeX. Several points have been clarified, though results remain the same. Minor typos corrected, and references updated. Version to appear in Phys. Rev.

    Histone deacetylases as new therapy targets for platinum-resistant epithelial ovarian cancer

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    Introduction: In developed countries, ovarian cancer is the fourth most common cancer in women. Due to the nonspecific symptomatology associated with the disease many patients with ovarian cancer are diagnosed late, which leads to significantly poorer prognosis. Apart from surgery and radiotherapy, a substantial number of ovarian cancer patients will undergo chemotherapy and platinum based agents are the mainstream first-line therapy for this disease. Despite the initial efficacy of these therapies, many women relapse; therefore, strategies for second-line therapies are required. Regulation of DNA transcription is crucial for tumour progression, metastasis and chemoresistance which offers potential for novel drug targets. Methods: We have reviewed the existing literature on the role of histone deacetylases, nuclear enzymes regulating gene transcription. Results and conclusion: Analysis of available data suggests that a signifant proportion of drug resistance stems from abberant gene expression, therefore HDAC inhibitors are amongst the most promising therapeutic targets for cancer treatment. Together with genetic testing, they may have a potential to serve as base for patient-adapted therapies

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

    Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

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    The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

    Patient Concerns Inventory for head and neck cancer: Brazilian cultural adaptation

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    Objective: The purpose of this study was to translate, culturally validate and evaluate the Patients Concerns Inventory - Head and Neck (PCI- H&amp;N) in a consecutive series of Brazilian patients. Methods: This study included adult patients treated for upper aerodigestive tract (UADT) cancer. The translation and cultural adaptation of the PCI–H&amp;N followed internationally accepted guidelines and included a pretest sample of patients that completed the first Brazilian-Portuguese version of the PCI. The use/feasibility/acceptability of the PCI was tested subsequently in a consecutive series of UADT cancer patients that completed the final Brazilian-Portuguese version of the PCI and a Brazilian-Portuguese version of the University of Washington Quality of Life Questionnaire (UW-QOL). Associations between physical and socio emotional composite scores from the UW-QOL and PCI were analyzed. Results: Twenty patients participated in the pretest survey (translation and cultural adaptation process), and 84 patients were analysed in the cultural validation study. Issues most selected were: fear of cancer returning, dry mouth, chewing/eating, speech/voice/being understood, swallowing, dental health/teeth, anxiety, fatigue/tiredness, taste and fear of adverse events. The three specialists most selected were speech therapist, dentist and psychologist. Statistically significant relationships between PCI and UW-QOL were found. Conclusions: The translation and cultural adaptation of the PCI for Brazilian-Portuguese language was successful, and the results demonstrate its feasibility and usefulness, making this a valuable tool for use within the Brazilian H&amp;N cancer population

    Tephrochronology

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    Tephrochronology is the use of primary, characterized tephras or cryptotephras as chronostratigraphic marker beds to connect and synchronize geological, paleoenvironmental, or archaeological sequences or events, or soils/paleosols, and, uniquely, to transfer relative or numerical ages or dates to them using stratigraphic and age information together with mineralogical and geochemical compositional data, especially from individual glass-shard analyses, obtained for the tephra/cryptotephra deposits. To function as an age-equivalent correlation and chronostratigraphic dating tool, tephrochronology may be undertaken in three steps: (i) mapping and describing tephras and determining their stratigraphic relationships, (ii) characterizing tephras or cryptotephras in the laboratory, and (iii) dating them using a wide range of geochronological methods. Tephrochronology is also an important tool in volcanology, informing studies on volcanic petrology, volcano eruption histories and hazards, and volcano-climate forcing. Although limitations and challenges remain, multidisciplinary applications of tephrochronology continue to grow markedly

    A comparison of the seasonal movements of tiger sharks and green turtles provides insight into their predator-prey relationship

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    During the reproductive season, sea turtles use a restricted area in the vicinity of their nesting beaches, making them vulnerable to predation. At Raine Island (Australia), the highest density green turtle Chelonia mydas rookery in the world, tiger sharks Galeocerdo cuvier have been observed to feed on green turtles, and it has been suggested that they may specialise on such air-breathing prey. However there is little information with which to examine this hypothesis. We compared the spatial and temporal components of movement behaviour of these two potentially interacting species in order to provide insight into the predator-prey relationship. Specifically, we tested the hypothesis that tiger shark movements are more concentrated at Raine Island during the green turtle nesting season than outside the turtle nesting season when turtles are not concentrated at Raine Island. Turtles showed area-restricted search behaviour around Raine Island for ~3&ndash;4 months during the nesting period (November&ndash;February). This was followed by direct movement (transit) to putative foraging grounds mostly in the Torres Straight where they switched to area-restricted search mode again, and remained resident for the remainder of the deployment (53&ndash;304 days). In contrast, tiger sharks displayed high spatial and temporal variation in movement behaviour which was not closely linked to the movement behaviour of green turtles or recognised turtle foraging grounds. On average, tiger sharks were concentrated around Raine Island throughout the year. While information on diet is required to determine whether tiger sharks are turtle specialists our results support the hypothesis that they target this predictable and plentiful prey during turtle nesting season, but they might not focus on this less predictable food source outside the nesting season
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