276 research outputs found

    Pion form factor in the Kroll-Lee-Zumino model

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    The renormalizable Abelian quantum field theory model of Kroll, Lee, and Zumino is used to compute the one-loop vertex corrections to the tree-level, Vector Meson Dominance (VMD) pion form factor. These corrections, together with the known one-loop vacuum polarization contribution, lead to a substantial improvement over VMD. The resulting pion form factor in the space-like region is in excellent agreement with data in the whole range of accessible momentum transfers. The time-like form factor, known to reproduce the Gounaris-Sakurai formula at and near the rho-meson peak, is unaffected by the vertex correction at order O\cal{O}(g_\rpp^2).Comment: Revised version corrects a misprint in Eq.(1

    Global Prevalence of Fuchs Endothelial Corneal Dystrophy (FECD) in Adult Population: A Systematic Review and Meta-Analysis

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    Purpose. To evaluate the global prevalence of Fuchs endothelial corneal dystrophy (FECD). Design. Systematic review and meta-analysis. Methods. A systematic electronic literature search was conducted on PubMed/MedLine, Cochrane Library, and Google Scholar, in order to select papers analysing the prevalence rate of FECD. Two authors independently conducted the electronic search. After removal of duplicates, title and abstract screening, and full-text analysis, data from selected articles were archived in a customized Excel spreadsheet. Risk of bias assessment was performed using the Joanna Briggs Institute Prevalence Critical Appraisal Tool. Meta-analysis was conducted using R (version 1.4.1106, package "meta"). Results. A total of 6660 eligible articles were retrieved from the initial electronic search. Only 4 original works were included in the qualitative and quantitative analysis. Of the 4746 patients included in this meta-analysis (i.e., 2232 male (M) and 2322 female (F)), we retrieved 269 FECD cases (81 M; 188 F), with a pooled prevalence estimates of 7.33% (95% CI: 4.08-12.8%). Statistically significant gender-related differences in the prevalence of FECD emerged by the analysis (OR: 2.22; 95% CI: 1.66-2.96, p=0.0016). While the total number of people aged >30 years with FECD is nowadays estimated at nearly 300 million, an increase of 41.7% in the number of FECD-affected patients is expected by 2050, when the overall figure is supposed to rise up to 415 million. Conclusion. This study provides a reliable figure of the present and future epidemiological burden of FECD globally, which might be useful for the design of FECD screening, treatment, rehabilitation, and related public health strategies

    Lax eyelid condition (LEC) and floppy eyelid syndrome (FES) prevalence in obstructive sleep apnea syndrome (OSA) patients: a systematic review and meta-analysis

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    Purpose: Lax eyelid condition (LEC) and floppy eyelid syndrome (FES) represent two distinct conditions which have been associated with several ocular and systemic comorbidities. The main aim of this systematic review and meta-analysis is to explore the available literature to estimate the prevalence rate of LEC and FES in obstructive sleep apnea (OSA). Methods: The protocol of this systematic review and meta-analysis has been registered in PROSPERO. Four electronic databases (PubMed/MEDLINE, Google Scholar, Cochrane Library, Web of Science) were searched from inception to December 24, 2021. A random intercept logistic regression model was carried out for the analysis of overall proportions. Odds ratio and mean difference were reported as measures of the effect size in the presence of binary and continuous outcomes, respectively. The estimated numbers of LEC/FES patients in OSA were calculated by multiplying the prevalence rate determined by our random-effects model and the corresponding Benjafield et al.’s population prospect. Results: We included 11 studies comprising 1225 OSA patients of whom 431 and 153 affected by LEC and FES, respectively. Our model estimated a pooled prevalence rate for LEC and FES in OSA patients of 40.2% (95%CI: 28.6–53.1%) and of 22.4% (95%CI: 13.8–34.2%), respectively. The number of LEC/FES affected individuals among OSA patients is expected to peak up to 376 and to 210 million, respectively. OSA patients appeared to have a 3.4 (95%CI: 2.2–5.2) and a 3.0 (95%CI: 1.7–5.5) increased risk of developing LEC and FES than the healthy counterpart. Conclusion: Prevalence of LEC and FES is higher in OSA-affected patients compared to controls. More studies are warranted to investigate the mechanisms leading to the development of LEC and/or FES in OSA patients, as well as the feasibility of the adoption of these clinical findings as screening tools for OSA

    Construction of an Immigrant Integration Composite Indicator through the Partial Least Squares Structural Equation Model K-Means

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    Integration is a multidimensional process, which can take place in different ways and at different times in relation to each of the single economic, social, cultural, and political dimensions. Hence, examining every single dimension is important as well as building composite indexes simultaneously inclusive of all dimensions in order to obtain a complete description of a complex phenomenon and to convey a coherent set of information. In this paper, we aim at building an immigrant integration composite indicator (IICI), able to measure the different aspects related to integration such as employment, education, social inclusion, active citizenship, and on the basis of which to simultaneously classify territorial areas such as European regions. For this application, the data collected in 274 European regions from the European Social Survey (ESS), Round 8, on immigration have been used

    Chiral condensates from tau decay: a critical reappraisal

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    The saturation of QCD chiral sum rules is reanalyzed in view of the new and complete analysis of the ALEPH experimental data on the difference between vector and axial-vector correlators (V-A). Ordinary finite energy sum rules (FESR) exhibit poor saturation up to energies below the tau-lepton mass. A remarkable improvement is achieved by introducing pinched, as well as minimizing polynomial integral kernels. Both methods are used to determine the dimension d=6 and d=8 vacuum condensates in the Operator Product Expansion, with the results: {O}_{6}=-(0.00226 \pm 0.00055) GeV^6, and O_8=-(0.0053 \pm 0.0033) GeV^8 from pinched FESR, and compatible values from the minimizing polynomial FESR. Some higher dimensional condensates are also determined, although we argue against extending the analysis beyond dimension d = 8. The value of the finite remainder of the (V-A) correlator at zero momentum is also redetermined: \Pi (0)= -4 \bar{L}_{10}=0.02579 \pm 0.00023. The stability and precision of the predictions are significantly improved compared to earlier calculations using the old ALEPH data. Finally, the role and limits of applicability of the Operator Product Expansion in this channel are clarified.Comment: Replaced versio

    Tomografia por impedância elétrica e seus possíveis usos na agropecuária.

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    bitstream/CNPDIA/10189/1/PA26_98.pd

    Differential X-ray attenuation in MA-XRF analysis for a non-invasive determination of gilding thickness

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    When investigating gilded artifacts or works of art, the determination of the gilding thickness plays a significant role in establishing restoration protocols or conservation strategies. Unfortunately, this is done by cross-sectioning the object, a destructive approach not always feasible. A non-destructive alternative, based on the differential attenuation of fluorescence radiation from the sample, has been developed in the past years, but due to the intrinsic random nature of X-rays, the study of single or few spots of an objects surface may yield biased information. Furthermore, considering the effects of both porosity and sample inhomogeneities is a practice commonly overlooked, which may introduce systematic errors. In order to overcome these matters, here we propose the extrapolation of the differential-attenuation method from single-spot X-ray fluorescence (XRF) measurements to macro-XRF (MA-XRF) scanning. In this work, an innovative algorithm was developed for evaluating the large amount of data coming from MA-XRF datasets and evaluate the thickness of a given overlapping layer over an area. This approach was adopted to study a gilded copper-based buckle from the sixteenth to seventeenth century found in Rome. The gilded object under investigation was also studied by other analytical techniques including scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). Previous results obtained from SEM-EDS were used to confront the data obtained with the proposed methodology and validate it. MA-XRF elemental distribution maps were fundamental in identifying and choosing sampling areas to calculate the thickness of the gilding layer, avoiding lead islands present in the sample that could negatively influence the results. Albeit the large relative standard deviation, the mean thickness values fell within those found in literature and those obtained from previous studies with SEM-EDS. Surface fissure has been found to deeply affect the results obtained, an aspect that is often disregarded

    Mental, Social and Visual Alienation in D’Alessandro’s Photography

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    This chapter analyzes the first of several photobooks that illustrated the reform of psychiatric health care in Italy in the 1960s and 1970s: Luciano D’Alessandro’s 1969 Gli esclusi. In 1967, D’Alessandro was invited by the director of the asylum of Nocera Superiore, Sergio Piro, to document through photography the abysmal conditions of the “total institution” that was the pre-reform mental hospital. D’Alessandro first published a small selection of photos, in Popular Photography Italiana (1967), which he then expanded in Gli esclusi. This chapter claims that, in the evolution between the two publications, we can read the complex and multilayered notion of alienation that informed the work of reform, especially that of one of the most famous figures associated with it, Franco Basaglia. By analyzing D’Alessandro’s Gli esclusi through the notion of alienation, this chapter lets what Sekula calls the conditions of “readability” of the photographic message emerge

    Lindane and Endosulfan Sulfate Isomers in Crassostrea virginica (Gmelin, 1791) Oyster Populations in Lagoon Systems from Central Gulf of Mexico

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    The aim of this study was to determine Lindane and Endosulfan Sulfate isomers in Crassostrea virginica oyster populations (Gmelin, 1791) in the Mandinga and Alvarado lagoon systems located in the central Gulf of Mexico. Samples were taken from the main oyster banks of each lagoon system, during the three representative seasons of the region, wet, dry and north winds. By means of free diving, 30 commercial size oysters (7 ± 3 cm) were collected in four oyster banks or stations of the Mandinga lagoon system, totaling 360 organisms, while in the Alvarado lagoon system there were a total of 90 oysters during the annual cycle. Concentration of lindane and endosulfan sulfate isotopes in C. virginica was performed with a gas chromatograph (Thermo Electron Model Trace GC Ultra 115V, Thermo Fisher Scientific Inc©, Monterrey, Nuevo León, México) with an Electron capture detector. Results showed that in the Alvarado Lagoon system mean concentrations of C. virginica oysters for lindane pesticide were 4.11 ± 3.83 ng⋅g-1, whereas for the Mandinga lagoon system, were 8.69 ± 5.15 ng⋅g-1. Endosulfan sulfate showed the highest average concentration in the Mandinga lagoon system with 24.68 ± 1.20 ng ⋅g-1. In addition, the endosulfan sulfate presents differences in its spatial distribution; high concentration levels in the Mandinga lagoon system whereas the lindane heterogeneity at all sampling points in both lagoons. Values of concentrations and relationships between compounds suggest recent contributions that could correspond to the excessive fluctuations of water discharged into the lagoon caused by the atypical rains of the year of sampling. It was concluded that endosulfan sulfate and lindane show concentration in all the points of sampling in both lagoons
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