Stochastic Quantization of Topological Field Theory: Generalized Langevin Equation with Memory Kernel

We use the method of stochastic quantization in a topological field theory defined in an Euclidean space, assuming a Langevin equation with a memory kernel. We show that our procedure for the Abelian Chern-Simons theory converges regardless of the nature of the Chern-Simons coefficient

The importance of the mixed phase in hybrid stars built with the Nambu-Jona-Lasinio model

We investigate the structure of hybrid stars based on two different constructions: one is based on the Gibbs condition for phase coexistence and considers the existence of a mixed phase (MP), and the other is based on the Maxwell construction and no mixed phase is obtained. The hadron phase is described by the non-linear Walecka model (NLW) and the quark phase by the Nambu-Jona-Lasinio model (NJL). We conclude that the masses and radii obtained are model dependent but not significantly different for both constructions.Comment: 8 pages, 7 figures, 3 table

Failure regime in (1+1) dimensions in fibrous materials

In this paper, we introduce a model for fracture in fibrous materials that takes into account the rupture height of the fibers, in contrast with previous models. Thus, we obtain the profile of the fracture and calculate its roughness, defined as the variance around the mean height. We investigate the relationship between the fracture roughness and the fracture toughness.Comment: 4 pages, 4 figures.eps, Revte

Hepatitis C infection at a tertiary hospital in South Africa: Clinical presentation, non-invasive assessment of liver fibrosis, and response to therapy

Background. Hepatitis C is a viral infection that leads to chronic liver disease, resulting in significant morbidity and mortality.Objectives. To describe the demographic characteristics and clinical presentation of patients with chronic hepatitis C infection. The aspartate aminotransferase-to-platelet ratio index (APRI) and the fibrosis index based on 4 factors (FIB-4) were assessed for prediction of liver fibrosis.Methods. We retrospectively reviewed 87 records of patients who presented to the liver clinic at Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa, from January 2007 to December 2016. Patients’ records were reviewed and analysed using SPSS statistical software version 24. Convenience sampling was used.Results. The patients’ mean (standard deviation (SD)) age was 52.6 (12.3) years. Fifty-four percent were female. Hepatitis C virus genotype 5 was exclusively found in blacks (p<0.001), constituting 60.3% of infections in this ethnic group and 48.7% in the cohort, followed by genotype 1 (21.8%), genotype 3 (15.4%), genotype 4 (10.3%) and mixed-genotype infections (3.8%). Genotype 5 patients were older (mean (SD) age 56.7 (9.8) years) than genotype 1 (46.3 (11.4) years) and genotype 3 (42 (9.8) years) (p=0.002 and p<0.001, respectively). The receiver operating characteristic curve for METAVIR F0 v. APRI (cut-off <0.7) showed a moderate correlation, with an area under the curve (AUC) of 0.349 (p=0.002), sensitivity of 78.8%, specificity of 70.6% and a negative predictive value (NPV) of 63.2%. METAVIR F4 v. APRI (cut-off ≥1.5) showed an AUC of 0.881 (p=0.001) with sensitivity of 85.7%, specificity of 93% and a positive predictive value (PPV) of 67%. METAVIR F0 v. FIB-4 (cut-off <1.45) showed a moderate correlation, with an AUC of 0.332 (p=0.021), sensitivity of 78.3%, specificity of 53.8% and an NPV of 73.7%. METAVIR F4 v. FIB-4 (cut-off >3.25) had a strong correlation, with an AUC of 0.952 (p<0.001), sensitivity of 63.6%, specificity of 100% and a PPV of 100%. Early virological response (EVR) was found to predict sustained virological response (SVR) to therapy (odds ratio 27.8; 95% confidence interval 2.8 - 274.3; p=0.004).Conclusions. Compared with other genotypes, genotype 5 was predominant in our cohort, particularly in older age groups. Moreover, APRI and FIB-4 scores correlated significantly with advanced fibrosis in HCV patients. Finally, EVR during therapy was found to determine SVR

The Bekenstein Bound in Asymptotically Free Field Theory

For spatially bounded free fields, the Bekenstein bound states that the specific entropy satisfies the inequality $\frac{S}{E} \leq 2 \pi R$, where $R$ stands for the radius of the smallest sphere that circumscribes the system. The validity of the Bekenstein bound on the specific entropy in the asymptotically free side of the Euclidean $(\lambda\,\phi^{\,4})_{d}$ self-interacting scalar field theory is investigated. We consider the system in thermal equilibrium with a reservoir at temperature $\beta^{\,-1}$ and defined in a compact spatial region without boundaries. Using the effective potential, we presented an exhaustive study of the thermodynamic of the model. For low and high temperatures the system presents a condensate. We obtain also the renormalized mean energy $E$ and entropy $S$ for the system. With these quantities, we shown in which situations the specific entropy satisfies the quantum bound

Ocorrência de Dichomeris famulata Meyrick (Lepidoptera: Gelechiidae) na cultura de milho orgânico solteiro ou consorciado com feijão.

A lagarta de Dichomeris famulata (Lepidoptera: Gelechiidae) danifica os grãos e compromete a germinação da semente. Sua ocorrência em milho no Brasil, especialmente em milho orgânico não tem sido evidenciada. No entanto, observações de campo têm sugerido que a praga pode tornar um problema real para o agricultor. Este trabalho teve como objetivo avaliar. a ocorrência da praga em espigas de milho cultivado no sistema orgânico. solteiro ou consorciado com feijão. No consórcio milho/feijão a ocorrência de D. famulata foi menor do que no sistema solteiro. porém sua presença foi constante em todas as avaliações. indicando de fato que o inseto pode vir a ser uma praga importante para o milho orgânico

The Rarita-Schwinger Particles Under de Influence of Strong Magnetic Fields

In this work, we calculate the solutions of the Rarita-Schwinger equation with the inclusion of the eletromagnetic interaction. Our gauge and coupling prescription choices lead to Dirac-type solutions. One of the consequences of our results are the Landau level occupation of particles, quite different from the usual spin 1/2 particle system occupation numbers.Comment: 12 page

Nonuniversality in the pair contact process with diffusion

We study the static and dynamic behavior of the one dimensional pair contact process with diffusion. Several critical exponents are found to vary with the diffusion rate, while the order-parameter moment ratio m=\bar{rho^2} /\bar{rho}^2 grows logarithmically with the system size. The anomalous behavior of m is traced to a violation of scaling in the order parameter probability density, which in turn reflects the presence of two distinct sectors, one purely diffusive, the other reactive, within the active phase. Studies restricted to the reactive sector yield precise estimates for exponents beta and nu_perp, and confirm finite size scaling of the order parameter. In the course of our study we determine, for the first time, the universal value m_c = 1.334 associated with the parity-conserving universality class in one dimension.Comment: 9 pages, 5 figure

Cardiopatias Congénitas Complexas: Influência do Diagnóstico Pré-Natal

INTRODUCTION: Complex congenital heart disease is a group of severe conditions. Prenatal diagnosis has implications on morbidity and mortality for most severe conditions. The purpose of this work was to evaluate the influence of prenatal diagnosis and distance of residence and birth place to a reference center, on immediate morbidity and early mortality of complex congenital heart disease. MATERIAL AND METHODS: Retrospective study of complex congenital heart disease patients of our Hospital, born between 2007 and 2012. RESULTS: There were 126 patients born with complex congenital heart disease. In 95%, pregnancy was followed since the first trimester, with prenatal diagnosis in 42%. There was a statistically significant relation between birth place and prenatal diagnosis. Transposition of great arteries was the most frequent complex congenital heart disease (45.2%), followed by pulmonary atresia with ventricular septal defect (17.5%) and hypoplastic left ventricle (9.5%). Eighty-two patients (65.1%) had prostaglandin infusion and 38 (30.2%)were ventilated before an intervention. Surgery took place in the neonatal period in 73%. Actuarial survival rate at 30 days, 12 and 24 months was 85%, 80% and 75%, respectively. There was no statistically significant relation between prenatal diagnosis and mortality. DISCUSSION: Most patients with complex congenital heart disease did not have prenatal diagnosis. All cases with prenatal diagnosis were born in a tertiary center. Prenatal diagnosis did not influence significantly neonatal mortality, as already described in other studies with heterogeneous complex heart disease. CONCLUSION: prenatal diagnosis of complex congenital heart disease allowed an adequate referral. Most patients with complex congenital heart disease were not diagnosed prenatally. This data should be considered when planning prenatal diagnosis of congenital heart disease