Behavior of a bipartite system in a cavity

We study the time evolution of a superposition of product states of two dressed atoms in a spherical cavity in the situations of an arbitrarily large cavity (free space) and of a small one. In the large-cavity case, the system dissipates, whereas, for the small cavity, the system evolves in an oscillating way and never completely decays. We verify that the von Neumann entropy for such a system does not depend on time, nor on the size of the cavityComment: 9 pages 2 figures, Revtex, Version accepted to be published in Physical Review

Statistical properties of detrended fluctuation analysis

The main goal of this work is to consider the detrended fluctuation analysis (DFA), proposed by Peng et al. [Mosaic organization of DNA nucleotides, Phys. Rev. E. 49(5) (1994), 1685–1689]. This is a wellknown method for analysing the long-range dependence in non-stationary time series. Here we describe the DFA method and we prove its consistency and its exact distribution, based on the usual i.i.d. assumption, as an estimator for the fractional parameter d. In the literature it is well established that the nucleotide sequences present long-range dependence property. In this work, we analyse the long dependence property in view of the autoregressive moving average fractionally integrated ARFIMA(p, d, q) processes through the analysis of four nucleotide sequences. For estimating the fractional parameter d we consider the semiparametric regression method based on the periodogram function, in both classical and robust versions; the semiparametric R/S(n) method, proposed by Hurst [Long term storage in reservoirs, Trans. Am. Soc. Civil Eng. 116 (1986), 770–779] and the maximum likelihood method (see [R. Fox and M.S. Taqqu, Large-sample properties of parameter estimates for strongly dependent stationary Gaussian time series, Ann. Statist. 14 (1986), 517–532]), by considering the approximation suggested by Whittle [Hypothesis Testing in Time Series Analysis (1953), Hafner, New York]..info:eu-repo/semantics/publishedVersio

α-stable laws for noncoding regions in DNA sequences

In this work, we analyze the long-range dependence parameter for a nucleotide sequence in several different transformations. The long-range dependence parameter is estimated by the approximated maximum likelihood method, by a novel estimator based on the spectral envelope theory, by a regression method based on the periodogram function, and also by the detrended fluctuation analysis method. We study the length distribution of coding and noncoding regions for all Homo sapiens chromosomes available from the European Bioinformatics Institute. The parameter of the tail rate decay is estimated by the Hill estimator αˆ. We show that the tail rate decay is greater than 2 for coding regions, while for almost all noncoding regions it is less than 2.info:eu-repo/semantics/publishedVersio

Evidência de infecção ativa por herpesvírus 6 (variante- A) em pacientes com linfadenopatia em Belém, Pará, Brasil

A total of 323 patients with lymphadenopathy were selected in Belém, Brazil, between January 1996 and December 2001, and screened for the presence of human herpesvirus-6 (HHV-6) IgM- and- IgG antibodies by enzyme-linked immunosorbent assay (ELISA). When seroprevalence is analyzed by gender, similar rates are found for female (60.6%) and male (55.7%) individuals. Seventy-seven (23.8%) patients were HHV-6-IgM-and- IgG-positive (IgM+ subgroup), with positivity rates of 29.7% and 17.7% (p = 0.0007) for female- and male individuals, respectively. Sera from a subgroup (n = 120) of these subjects, with high HHV-6 antibody levels (either IgM+ or IgG+ reactivities), were subsequently processed for the presence of HHV-6 DNA by polymerase chain reaction (PCR)/nested PCR. Active infections (IgM+ and/or IgG+ high levels specific antibodies plus detection of viral DNA) were diagnosed in 20/77 (20.0%) and 8/43 (18.6%); subgroup of the 120 individuals suspected of having HHV-6 suggestive recent infection. All (n = 28) cases of active infection were found to be associated with HHV-6 variant-A (HHV-6A), as detectable by PCR/nested PCR, using variant-specific primer that amplify regions of 195 base pairs (bp) (HHV-6A) and 423 bp (HHV-6B). Rates of HHV-6 DNA detection between female and male patients were similar (p >; 0.05) in the IgM+ and IgG+ groups: 20.4% versus 35.7% and 25.0% versus 13.0%, respectively. HHV-6 DNA was detected across ; 50 age-groups at rates that ranged from 15.4% (male, ; 0,05) em pacientes dos sexos feminino e masculino, no grupo IgM+ e IgG+ com: 20,4% versus 35,7% e 25,0% versus 13,0%, respectivamente. A detecção do DNA viral do HHV-6 ocorreu no grupo etário ; 50 anos, com taxas que variaram de 15,4% (homens, < 5 anos) a 100,0% (mulheres, 11-20 anos). O aumento dos linfonodos cervicais foi registrado como mais freqüente, ocorrendo em número de 9 (32,0%) casos, tanto entre indivíduos do sexo masculino como naqueles do feminino. Entre os pacientes (n = 28) com infecção ativa pela variante A do HHV-6, a duração dos sintomas em 35,7% deles foi de 1-5 dias, enquanto em 64,3% durou de 6-20 dias. Nossos dados sugerem ser importante investigar a infecção pelo HHV-6 entre os pacientes (crianças e adultos) portadores de linfadenopatia como manifestação clínica proeminente no curso das doenças agudas febris

Vanishing value chains, industrial districts and HRM in the Brazilian automotive industry

Industrial districts in the Brazilian automotive industry have facilitated just-in-time production, functional flexibility, and compatibility of HR practices since the 1980s. However, this model has been threatened by global over-capacity and the rise of low cost suppliers in South Korea and China. This paper develops literature on proximity dynamics though exploring the influence of global supply chains on HRM in industrial districts. The more specific research questions are: How viable are industrial districts in the context of global crises? And how is this viability bound up with the awareness of HR practices down the supply chain? The findings indicate that the industrial districts model is under threat. In the context of global supply chains, automotive majors have shifted costs onto their suppliers, disrupting established relationships, and moreover, they often lack knowledge of the employment practices of distant suppliers. Yet, in times of political and economic uncertainty, worker rights might be best served by geographical and cognitive proximity

A Generalized Gauge Invariant Regularization of the Schwinger Model

The Schwinger model is studied with a new one - parameter class of gauge invariant regularizations that generalizes the usual point - splitting or Fujikawa schemes. The spectrum is found to be qualitatively unchanged, except for a limiting value of the regularizing parameter, where free fermions appear in the spectrum.Comment: 16 pages, SINP/TNP/93-1

Fifth disease in children living in Belém, Brazil

Amostras de soro colhidas na fase aguda de doença exantemática, acomentendo duas crianças, revelaram-se positivas quanto à presença de IgM específica para o vírus B 19, através do método de rádio-imuno-ensaio por mecanismo de captura. O primeiro paciente, um menino de dois anos, apresentou erupção cutânea com seis dias de duração; o segundo foi uma menina de quatro anos de idade, irmã do primeiro paciente e que foi submetida a exame à mesma época em que se procedeu à avaliação clínica do irmão, e que exibia "rash" cutâneo que evoluía há três dias.Acute sera from two children suffering from an illness with an erythematous rash were positive for B 19 virus specific IgM antibody, as tested by a capture radioimmunoassay. The first patient, a two year old boy, presented with a cutaneous rash of six days duration, the second was a four year old girl, sister of the first patient, who was examined at the same time and had a three day history of cutaneous rash

Implementation of PRRSV status classification system in swine breeding herds from a large integrated group in Spain

Background: Porcine Reproductive and Respiratory Syndrome (PRRS) is an endemic swine disease causing significant productive and economic losses. Knowledge of PRRS epidemiology is crucial to develop control strategies against this disease. In that regard, classifying farms according to PRRS virus (PRRSV) shedding and exposure, and understanding key drivers of change in status over time, provides great applied knowledge for developing disease control programs. In most European countries, PRRSV monitoring is performed most frequently at the individual farm level although criteria selected for monitoring varies among different regions and farms. The aim of this study was to implement a systematic monitoring program for PRRSV in Spanish sow farms. Breeding herds were classified according to a standardized PRRSV infection status using sampling programs and terminology currently adopted in the United States (US), which allowed an evaluation of PRRSV epidemiology in a large integrated Spanish group during a one-year study period (February 2017–March 2018). Results: Fifteen farms achieved a stable PRRSV status after the first 4 consecutive samplings and 20 farms were classified as unstable. One of the farms maintained a stable status throughout the duration of the whole monitoring period. Among the 20 farms classified as unstable at the beginning of the monitoring protocol, 9 farms (45%) never reached the stable status and 11 farms (55%) reached stable status afterwards during the monitoring study period. From PRRSV PCR positive pools, there were 47 different PRRSV nucleotide sequences from 24 different farms. More than one PRRSV sequence was obtained from 15 farms. In the farms with more than one sequence detected, we observed recirculation of the same PRRSV field strain in 7 farms and introduction of a different PRRSV strain in 5 farms and both events in 3 farms. Conclusions: Systematic monitoring for PRRSV in breeding herds established a basis of knowledge of PRRSV epidemiology at the farm level and provided key data to classify farms according to PRRSV exposure and shedding status. These data allow further evaluation of the impact of the PRRSV farm status on production and economic performance in breeding herds and additional investigation of factors related to PRRSV epidemiology