Static critical behavior of the ferromagnetic transition in LaMnO3.14 manganite

The ferromagnetic phase transition in LaMnO3.14 is investigated by measuring the dc magnetization as a function of magnetic field and temperature. Modified Arrott plot and Kouvel Fisher analysis yield estimates for the critical exponents beta, and gama, with values between that predicted for the Heisenberg model and mean field theory. At low fields we found an anomalous small value of beta, indicating that the critical behavior is influenced by the range of magnetic fields used.Comment: Presented at ICM 2000 conference. Accepted for publication at J. Magn. Magn. Mate

Uma proposta estratégica de desenvolvimento municipal

Orientador: Rafael TortatoMonografia (especialização) - Universidade Federal do Paraná, Especialização em Desenvolvimento RegionalInclui referênciasResumo: Este trabalho foi elaborado com a finalidade de levantar informações sobre o município de Santa Terezinha de Itaipu, principalmente no que se refere ao turismo. E com essas informações fazer uma análise da situação atual para comprovar a necessidade de buscar uma estratégia de desenvolvimento do município através da atividade turística e também, confrontar a viabilidade de implantação desta proposta estratégica através da união do Programa de Regionalização do Turismo-Roteiros do Brasil do Ministério do Turismo e do Programa Empreender-Unir para Crescer da CACB (Confederação das Associações Comerciais do Brasil) e SEBRAE, portanto seguindo a linha de trabalho da Associação Comercial local para essa proposição. A metodologia utilizada para elaborar essa proposta de Planejamento Estratégico foi a técnica da pesquisa qualitativa, especificamente a pesquisaação, porém alicerçada nas orientações contidas nesses dois Programas. No entanto para a implantação do Plano de Desenvolvimento se faz necessário dar continuidade às orientações do Programa de Regionalização do Turismo- Roteiros do Brasil de, na seqüencia deste, formular um Planejamento Tático e Operacional. Esta metodologia está composta por uma primeira etapa de levantamentos de dados relevantes para o setor do turismo dentro do município, iniciando o trabalho pela busca do fortalecimento de sua base, fase de maior importância para a autora desta proposta, através do envolvimento consciente e comprometimento de todos os atores no processo. E por uma segunda etapa, a elaboração do planejamento estratégico propriamente dito, de análise situacional com prognóstico e a preparação de um possível produto turístico, reivindicação constante de vários empreendedores locais ao poder público. Espera-se como resultado conseguir unir e integrar o setor privado, público e terceiro setor na atividade turística para que as ações sejam canalizadas e somadas no sentido de desenvolvimento sustentável do municípi

Sums of magnetic eigenvalues are maximal on rotationally symmetric domains

The sum of the first n energy levels of the planar Laplacian with constant magnetic field of given total flux is shown to be maximal among triangles for the equilateral triangle, under normalization of the ratio (moment of inertia)/(area)^3 on the domain. The result holds for both Dirichlet and Neumann boundary conditions, with an analogue for Robin (or de Gennes) boundary conditions too. The square similarly maximizes the eigenvalue sum among parallelograms, and the disk maximizes among ellipses. More generally, a domain with rotational symmetry will maximize the magnetic eigenvalue sum among all linear images of that domain. These results are new even for the ground state energy (n=1).Comment: 19 pages, 1 figur

An artificial immune system for fuzzy-rule induction in data mining

This work proposes a classification-rule discovery algorithm integrating artificial immune systems and fuzzy systems. The algorithm consists of two parts: a sequential covering procedure and a rule evolution procedure. Each antibody (candidate solution) corresponds to a classification rule. The classification of new examples (antigens) considers not only the fitness of a fuzzy rule based on the entire training set, but also the affinity between the rule and the new example. This affinity must be greater than a threshold in order for the fuzzy rule to be activated, and it is proposed an adaptive procedure for computing this threshold for each rule. This paper reports results for the proposed algorithm in several data sets. Results are analyzed with respect to both predictive accuracy and rule set simplicity, and are compared with C4.5rules, a very popular data mining algorithm

Low temperature irreversibility induced by thermal cycles on two prototypical phase separated manganites

We have studied the effect of irreversibility induced by repeated thermal cycles on the electric transport and magnetization of polycrystalline samples of La0.5Ca0.5MnO3 and La0.325Pr0.3Ca0.375MnO3. An increase of the resistivity and a decrease of the magnetization at different temperature ranges after cycling is obtained in the temperature range between 300 K and 30 K. Both compounds are known to exhibit intrinsic submicrometric coexistence of phases and undergo a sequence of phase transitions related to structural changes. Changes induced by thermal cycling can be partially inhibited by applying magnetic field and hydrostatic pressure. Our results suggest that the growth and coexistence of phases with different structures gives rise to microstructural tracks and strain accommodation, producing the observed irreversibility. Irrespective of the actual ground state of each compound, the effect of thermal cycling is towards an increase of the amount of the insulating phase in both compounds.Comment: to appear in Journal of Alloys and Compounds (2003

Seminal quality, testicle and epididymis morphology of bulls fed a diet containing gossypol

The objective was to evaluate the effect of intake of free gossypol on sperm quality and morphology of the testicles and epididymis of Nelore bulls. Twelve bulls were fed diets containing 3.3g of free gossypol/bull/day (cottonseed) (Group 1, n = 6) and a diet free of gossypol (Group 2, n = 6), respectively. Semen samples were collected in the beginning and end of the experiment which lasted 73 days. In the end of the study the testes and epididymis of bulls were removed to study the effect of free gossypol on histological characteristics. The average consumption of 3.3g of free gossypol/bull/day (mean 7.1mg of free gossypol/kg/day) reduced motility and sperm concentration and increased the percentage of major and total sperm defects, as well as the animals showing testes with seminiferous tubules of smaller thickness, fewer layers of spermatogenic lineage cells, smaller epididymal epithelium thickness and smaller number of sperm within the epididymal ducts, compared to animals with a diet free of gossypol (Group 2). The consumption of 3.3g of free gossypol/bull/day led to changes in morphology and morphometry of the testes and epididymis and reduced sperm quality of bulls.Objetivou-se avaliar o efeito da ingestão de gossipol livre sobre a qualidade espermática e a morfologia dos testículos e dos epidídimos de touros da raça Nelore. Doze touros receberam dieta contendo 3,3g de gossipol livre/touro/dia (caroço de algodão) (Grupo 1, n=6) e dieta isenta de gossipol (Grupo 2, n=6), respectivamente. Foram realizadas coletas de sêmen no início e no final do experimento, que teve duração de 73 dias. Ao final do estudo, foram retirados os testículos e os epidídimos dos touros para se estudar o efeito do gossipol livre sobre as características histológicas. O consumo médio de 3,3g de gossipol livre/touro/dia (média 7,1mg de gossipol livre/kg/dia) reduziu a motilidade e a concentração espermática e aumentou a porcentagem de defeitos espermáticos maiores e totais. Além disso, os animais apresentaram testículos com túbulos seminíferos de menor espessura de parede, menor número de camadas de células espermatogênicas, menor espessura do epitélio epididimário e menor número de espermatozoide no interior dos ductos epidídimários, em relação aos animais com dieta isenta de gossipol (Grupo 2). O consumo de 3,3g de gossipol livre/touro/dia acarretou alterações na morfologia e na morfometria dos testículos e dos epidídimos e reduziu a qualidade espermática dos touros.Universidade de Cuiabá Faculdade de Medicina VeterináriaUFMS Faculdade de Medicina Veterinária e ZootecniaEpamigUniversidade Federal do Mato GrossoUNIFESP-EPMUNIFESP, EPMSciEL

Effect of environmental temperature during the of brooding period on growing period of pullets viscera and tibia

ArticlePoultry production in subtropical and tropical regions faces many problems, one of which is the high air temperature causing thermal stress, particularly dangerous in high-producing birds. Thus, the negative effects caused by heat stress (HS) must be managed. The objective of this study was to evaluate the effects of four different levels of HS in viscera and tibia of pullets. A total of 648 chicks (Lohmann LSL Lite) were used in this study in two different phases. The pre-experimental phase (PEP) was from day 1 through 6 weeks of age. The birds were reared with three different environmental temperatures: thermal comfort, hot and cold. The experimental phase (EP) was conducted from the 7th to the 17th week. Pullets from each thermal environment of the PEP were submitted to: 20 °C, 25 °C, 30 °C, 35 °C. At the end of the 17th week of age 120 pullets were euthanatized and the organs, heart, liver, spleen and gizzard were weighed, as also their tibias. Effects of PEP, and its interaction with EP, were not significant (P < 0.05) for viscera and tibia weight. However, a significant increase (P < 0.05) in heart weight with the decrease of the environmental temperature was observed, being the pullets subject to 20ºC and 25 °C with the heaviest weights. For the liver, pullets subject to the 35 °C had the lowest weight and were different (P < 0.05) from the other three treatments. For gizzard, the difference (P < 0.05) was between the treatments 20ºC and 35 °C. These results indicate that brooding temperatures tested during the first 6 weeks of life did not affect the viscera and bone weight during the growing phase

Limited risk of Zika virus transmission by five Aedes albopictus populations from Spain

Background: Aedes albopictus, the Asian tiger mosquito, is an exotic invasive species in Europe. It has substantial public health relevance due to its potential role in transmitting several human pathogens. Out of the European countries, Spain has one of the highest risk levels of autochthonous arbovirus transmission due to both the high density of Ae. albopictus and the extensive tourist influx from vector-endemic areas. This study aims to investigate the susceptibility of five Ae. albopictus populations from mainland Spain and the Balearic Islands to a Brazilian Zika virus (ZIKV) strain. Methods: The F1 generation of each Ae. albopictus population was orally challenged with a ZIKV-infected blood meal (1.8 × 10 PFU/ml). At 7 and 14 days post-infection (dpi), mosquito bodies (thorax and abdomen) and heads were individually analysed through RT-qPCR to determine the infection rate (IR) and dissemination rate (DR), respectively. The saliva of infected mosquitoes was inoculated in Vero cells and the transmission rate was assessed by plaque assay or RT-qPCR on ∼33 individuals per population. Results: The IR and DR ranged between 12-88%, and 0-60%, respectively, suggesting that ZIKV is capable of crossing the midgut barrier. Remarkably, no infectious viral particle was found in saliva samples, indicating a low ability of ZIKV to overcome the salivary gland barrier. A subsequent assay revealed that a second non-infective blood meal 48 h after ZIKV exposure did not influence Ae. albopictus vector competence. Conclusions: The oral experimental ZIKV infections performed here indicate that Ae. albopictus from Spain become infected and disseminate the virus through the body but has a limited ability to transmit the Brazilian ZIKV strain through biting. Therefore, the results suggest a limited risk of autochthonous ZIKV transmission in Spain by Ae. albopictus

Magnetic relaxation phenomena and cluster glass properties of La{0.7-x}Y{x}Ca{0.3}MnO{3} manganites

The dynamic magnetic properties of the distorted perovskite system La{0.7-x}Y{x}Ca{0.3}MnO{3} (0 <= x <= 0.15) have been investigated by ac-susceptibility and dc magnetization measurements, with emphasis on relaxation and aging studies. They evidence for x >= 0.10 the appearance of a metallic cluster glass phase, that develops just below the ferromagnetic transition temperature. The clusters grow with decreasing temperature down to a temperature T(f0) at which they freeze due to severe intercluster frustration. The formation of these clusters is explained by the presence of yttrium induced local structural distortions that create localized spin disorder in a magnetic lattice where double-exchange ferromagnetism is dominant.Comment: Accepted for publication in Phys. Rev.