847 research outputs found

    Semiclassical thermodynamics of scalar fields

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    We present a systematic semiclassical procedure to compute the partition function for scalar field theories at finite temperature. The central objects in our scheme are the solutions of the classical equations of motion in imaginary time, with spatially independent boundary conditions. Field fluctuations -- both field deviations around these classical solutions, and fluctuations of the boundary value of the fields -- are resummed in a Gaussian approximation. In our final expression for the partition function, this resummation is reduced to solving certain ordinary differential equations. Moreover, we show that it is renormalizable with the usual 1-loop counterterms.Comment: 24 pages, 5 postscript figure

    A high HIF-1α expression genotype is associated with poor prognosis of upper aerodigestive tract carcinoma patients

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    SummaryThe aim of the present study was to evaluate the role of HIF-1α genetic polymorphisms and protein expression in the development of metastasis in upper aerodigestive tract cancer (UADTC) patients. The expression of pro-angiogenic markers was also evaluated. Protein expression was analysed using immunohistochemistry, and RFLP analysis was used to investigate HIF-1α C1779T and G1790A polymorphisms in 52 patients with UADTC. Primary lesions were divided into 2 groups according to the absence or presence of metastasis. Lymph node samples were divided into 3 groups: metastatic lymph nodes, non-metastatic lymph nodes (both derived from patients with metastatic disease), and control lymph nodes, which were obtained from patients without any metastasis. The allele T was more frequently found in patients with metastatic disease. HIF-1α protein expression in the lymph nodes was increased in the presence of the T allele. Metastatic lymph nodes showed lower levels of HIF-1α, VEGFR1, and MMP-9 proteins compared to lymph nodes without metastasis, while VEGFR2 protein levels were increased. In agreement, HIF-1α expression was correlated with MMP-9. Cox regression analysis demonstrated that higher HIF-1α and MMP-9 protein expression levels and GA and GG genotypes were associated with poor survival. Our findings show that the C1772T and G1790A polymorphisms of the HIF-1α gene are associated with increased expression of the HIF-1α protein in UADTC. The present data indicate that non-metastatic tissues express higher levels of HIF-1α, VEGFR1, and MMP-9, while in metastatic lymph nodes, VEGFR2 protein expression is elevated. The present study also shows that the HIF-1α G1790A polymorphism and its protein expression have an impact on the prognosis of UADTC patients

    Oral health of an indigenous population in northeastern Brazil: a cross-sectional Study of the Fulni-ô ethnic group

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    ABSTRACT BACKGROUND: There is a lack of studies evaluating the oral health of traditional indigenous communities in Brazil. OBJECTIVES: Thus, the objective of this study was to describe the oral health characteristics of the indigenous Fulni-ô ethnic group in Northeast Brazil. DESIGN AND SETTING: A cross-sectional observational investigation was conducted within the Project on Atherosclerosis among Indigenous Populations. METHODS: This study included participants of both sexes from the Fulni-ô ethnic group. The participants included in this investigation underwent a comprehensive oral health evaluation by a registered and experienced dentist to assess oral health and identify potentially malignant oral lesions. Participants with suspicious lesions were referred for biopsy. Shapiro-Wilk, Mann-Whitney, and Student’s t-tests were used, and measures of central tendency and dispersion were described. Statistical significance was 5%. RESULTS: A total of 104 individuals were included in this study. The prevalence of the use of tobacco derivatives was 94.0%, with similarities between sexes. The prevalence of oral changes in this study population was 84.4%. Fifty-one individuals who underwent oral reassessment were referred for oral lesion biopsy. CONCLUSIONS: This study demonstrated a high prevalence of oral alterations in the Fulni-ô population. Histopathological analyses indicated the presence of mild oral epithelial dysplasia in five cases

    "Sou escravo de oficiais da Marinha": a grande revolta da marujada negra por direitos no período pós-abolição (Rio de Janeiro, 1880-1910)

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    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

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    Measurement of B-c(2S)(+) and B-c*(2S)(+) cross section ratios in proton-proton collisions at root s=13 TeV

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