Vacuum Polarization by a Magnetic Flux Tube at Finite Temperature in the Cosmic String Spacetime

In this paper we analyse the effect produced by the temperature in the vacuum polarization associated with charged massless scalar field in the presence of magnetic flux tube in the cosmic string spacetime. Three different configurations of magnetic fields are taken into account: $(i)$ a homogeneous field inside the tube, $(ii)$ a field proportional to $1/r$ and $(iii)$ a cylindrical shell with $\delta$-function. In these three cases, the axis of the infinitely long tube of radius $R$ coincides with the cosmic string. Because the complexity of this analysis in the region inside the tube, we consider the thermal effect in the region outside. In order to develop this analysis, we construct the thermal Green function associated with this system for the three above mentioned situations considering points in the region outside the tube. We explicitly calculate in the high-temperature limit, the thermal average of the field square and the energy-momentum tensor.Comment: 16 pages, 1 figur

Environmental assessment of sardine (Sardina pilchardus) purse seine fishery in Portugal with LCA methodology including biological impact categories.

Purpose: The purse seine fishery for sardine is the most important fishery in Portugal. The aim of the present study is to assess the environmental impacts of sardine fished by the Portuguese fleet and to analyse a number of variables such as vessel size and time scale. An additional goal was to incorporate fishery-specific impact categories in the case study.\ud Methods: Life CycleAssessmentmethodologywas applied, and\ud data were collected from nine vessels, which represented around 10 % of the landings. Vessels were divided into two length categories, above and below 12 m, and data were obtained for the years 2005 to 2010. The study was limited to the fishing phase only. The standard impact categories included were energy use, global warming potential, eutrophication potential, acidification potential and ozone depletion potential. The fishery specific impact categories were overfishing, overfishedness, lost potential yield, mean trophic level and the primary production required, and were quantified as much as possible.\ud Results and discussion: The landings from the data set were\ud constituted mainly by sardine (91 %), and the remainders wereother small pelagic species (e.g. horse mackerel). The most important input was the fuel, and both vessel categories had the same fuel consumption per catch 0.11 l/kg. Average greenhouse gas emissions (carbon footprint) were 0.36 kg CO2 eq. per kilo sardine landed. The fuel use varied between years, and variability between months can be even higher. Fishing mortality has increased, and the spawning stock biomass has decreased resulting in consequential overfishing for 2010. A correlation between fuel use and stock biomass was not found, and the stock condition does not seem to directly influence the global warming potential in this fishery. Discards were primarily nontarget small pelagic species, and there was also mortality of target species resulting from slipping. The seafloor impact was considered to be insignificant due to the fishing method.\ud Conclusions: The assessment of the Portuguese purse seine fishery resulted in no difference regarding fuel use between large and small vessels, but differences were found between years. The stock has declined, and it has produced below maximum sustainable yield. By-catch and discard data were missing but may be substantial. Even being difficult to quantify, fishery impact categories complement the environmental results with biological information and precaution is need in relation to the stock management. The sardine carbon footprint from Portuguese purse seine was lower than that of other commercial species reported in

Grão de bico e lentilha: duas novas hospedeiras de Sclerotium rolfsii no Planalto Central do Brasil.

Neste trabalho, relata-se, pela primeira vez, a ocorrência da murcha-de-esclerócio, causada por Sclerotium rolfsii em grão-de-bico (Cicer arietinum L.) e em lentilha (Lens culinaris Medikus) na Região do Planalto Central do Brasil.bitstream/item/85036/1/bpd-92.pd

Structural Changes in Data Communication in Wireless Sensor Networks

Wireless sensor networks are an important technology for making distributed autonomous measures in hostile or inaccessible environments. Among the challenges they pose, the way data travel among them is a relevant issue since their structure is quite dynamic. The operational topology of such devices can often be described by complex networks. In this work, we assess the variation of measures commonly employed in the complex networks literature applied to wireless sensor networks. Four data communication strategies were considered: geometric, random, small-world, and scale-free models, along with the shortest path length measure. The sensitivity of this measure was analyzed with respect to the following perturbations: insertion and removal of nodes in the geometric strategy; and insertion, removal and rewiring of links in the other models. The assessment was performed using the normalized Kullback-Leibler divergence and Hellinger distance quantifiers, both deriving from the Information Theory framework. The results reveal that the shortest path length is sensitive to perturbations.Comment: 12 pages, 4 figures, Central European Journal of Physic

Efeitos do calor e fontes tolerância ao florescimento precoce em variedades de alface do tipo americana

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Esterilização de suco de abacaxi por microfiltração

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A planar Al-Si Schottky Barrier MOSFET operated at cryogenic temperatures

Schottky Barrier (SB)-MOSFET technology offers intriguing possibilities for cryogenic nano-scale devices, such as Si quantum devices and superconducting devices. We present experimental results on a novel device architecture where the gate electrode is self-aligned with the device channel and overlaps the source and drain electrodes. This facilitates a sub-5 nm gap between the source/drain and channel, and no spacers are required. At cryogenic temperatures, such devices function as p-MOS Tunnel FETs, as determined by the Schottky barrier at the Al-Si interface, and as a further advantage, fabrication processes are compatible with both CMOS and superconducting logic technology.Comment: 6 pages, 4 figures, minor changes from the previous version

AVALIANDO A GESTÃO UNIVERSITÁRIA PONTO A PONTO: ESTUDO DE CASO

O processo de avaliação do ensino superior segue duas vertentes principais: a avaliação centrada no planejamento institucional com metas e indicadores globais bem definidos e a avaliação setorizada ou pontual que permite uma visão detalhada das rotinas e envolvimento dos indivíduos com a instituição. Neste trabalho apresentamos os resultados da avaliação pontual interna e externa de um setor administrativo da Universidade Federal de Santa Catarina. A avaliação foi realizada através análise de questionários com questões abertas e de resposta induzida. Os questionários foram preenchidos anonimamente e de forma voluntária por servidores da unidade (32 respondidos de 34 questionários enviados) e por usuários dos serviços da unidade (81 respondidos de 138 questionários enviados). Os resultados mostram, entre outros, os seguintes pontos positivos da avaliação interna: alto grau de envolvimento dos servidores com o processo de avaliação; satisfação com o trabalho; ambiente de trabalho propício à troca de idéias. Dos pontos negativos podemos ressaltar: os servidores sentem uma distribuição desigual da carga de trabalho no setor e fora dele e manifestam a falta de reuniões periódicas com as chefias. A avaliação externa revela respostas elogiosas ao trabalho do setor mas também que parte dos serviços prestados não são bem conhecidos da comunidade universitária. A auto avaliação é mais severa do que a avaliação externa, mostrando o espírito crítico dos servidores do setor. A avaliação permite recomendar ações concretas para reforçar os pontos positivos e minimizar os aspectos negativos como, por exemplo, o estabelecimento de uma agenda de reuniões periódicas entre servidores e chefias. Concluímos, além dos resultados diretos, que a avaliação setorizada é um mecanismo válido de diagnóstico da gestão e que existe, na comunidade universitária, um ambiente propício à continuidade da aplicação deste método