Phase diagram of the antiferromagnetic XY model in two dimensions in a magnetic field

The phase diagram of the quasi-two-dimensional easy-plane antiferromagnetic model, with a magnetic field applied in the easy plane, is studied using the self-consistent harmonic approximation. We found a linear dependence of the transition temperature as a function of the field for large values of the field. Our results are in agreement with experimental data for the spin-1 honeycomb compound BaNi_2V_2O_3Comment: 3 page

The outcomes of entrepreneurship, relational capital and innovativeness on tourist satisfaction

Addressing the needs of customers is fundamental to the success of companies, particularly in the long-term. In fact, most companies use customer satisfaction as a method to determine and evaluate their performance and outline their strategies for the future. Therefore, the main objective is to better understand entrepreneurship and new product development antecedents and implications on customer satisfaction, a key element for sustainable development. A model is proposed to assess the relationship between two antecedents of entrepreneurial orientation (EO) and new product development (NPD) and a measure of performance. Based on a survey sample of 137 tourism SMEs, the model was tested using Partial Least Squares (PLS). The results show that both the relational capital and innovativeness positively influence entrepreneurship and NPD. They also suggest a positive relationship between entrepreneurship and customer satisfaction. Although there is a positive impact of NPD on customer satisfaction, this relationship was not significant. In addition, the results indicate that relational capital and innovativeness positively influence customer satisfaction through entrepreneurship and NPD. Consequently, to improve the sustainable performance of tourism firms and to increase customer satisfaction, managers must invest in the development of entrepreneurship as well as in the development of new products and their antecedents.info:eu-repo/semantics/publishedVersio

Evolução do uso da terra e qualidade da água na bacia do rio Salobra, MS.

A bacia hidrográfica é uma unidade básica para planejamento, dado que seus elementos naturais e antrópicos estão conectados pela água. Sendo assim as alterações ocorridas na sua superfície podem se refletir nos cursos d´água. Nesse sentido este trabalho tem como objetivo analisar a relação do uso da terra com possíveis alterações causadas na qualidade da água na bacia hidrográfica do rio Salobra, um importante afluente do Rio Miranda que drena o Pantanal. Foi usado o mapa existente de uso da terra de 1994 e elaborado o mapa de uso para 2007, utilizando imagens CBERS-2 e verificações a campo. Tais dados foram organizados no SIG Spring e, em seguida, comparados com dados da qualidade da água do rio Salobra. O desmatamento ocorre em 35% de sua área, sendo a pastagem plantada para pecuária de corte o principal uso. O desmatamento quase dobrou no período analisado, mas a qualidade da água se manteve boa, chegando a ótima em junho de 2001. Na análise individual dos parâmetros do IQA, observaram-se alterações em junho e agosto/1998, dez/1998 e nov/2001, sendo associadas a chuvas acima da média. O uso de imagens de satélite e trabalhos de campo permitiram detalhar o mapeamento de uso existente, mas a utilização de um único ponto de coleta e análise da qualidade da água não demonstrou nenhuma relação de impacto causado pelo aumento do desmatamento e forma de uso da bacia. Dessa forma sugere-se o aumento de pontos de coleta e análise da qualidade da água na bacia do rio Salobra.Geopantanal 2010

Automated search for star clusters in large multiband surveys: II. Discovery and investigation of open clusters in the Galactic plane

Automated search for star clusters in J,H,K_s data from 2MASS catalog has been performed using the method developed by Koposov et. al (2008). We have found and verified 153 new clusters in the interval of the galactic latitude -24 < b < 24 degrees. Color excesses E(B-V), distance moduli and ages were determined for 130 new and 14 yet-unstudied known clusters. In this paper, we publish a catalog of coordinates, diameters, and main parameters of all the clusters under study. A special web-site available at http://ocl.sai.msu.ru has been developed to facilitate dissemination and scientific usage of the results.Comment: 9 pages, 3 tables, 5 figures, accepted to Astronomy Letter

Caracterização de isolados de Fusarium oxysporum f. sp. cubense (Foc) quanto à compatibilidade vegetativa e à patogenicidade em cultivares de bananeira diferenciadoras de raça no Brasil.

Murcha de Fusarium é causada por Fusarium oxysporum f . sp. cubense (Foc), um patógeno altamente variável. Porém, o efeito da heterocariose sobre a classificação taxonômica e a importância da formação de um heterocário entre isolados selvagens de espécies de Fusarium ainda não é clara e permanece amplamente debatida. Assim como a recombinação parassexual tem sido relatada em F . oxysporum. f . sp. cubense , para explicar as relações genéticas entre isolados pertencentes à mesma raça ou formae specialis. Grupos assexuais isolados geneticamente e identificados nestes estudos, são denominados de grupos de compatibilidade vegetativa (GCV). P orém, outra forma de determinação de raças deste patógeno, tem sido através de variedades indicadoras, utilizando-se as variedades Gros Michel para a Raça 1; Bluggoe para a Raça 2; Grande Naine para a Raça 4. O presente estudo teve como objetivos determinar a diversidade genética entre isolados de Foc, através destas duas técnicas, de forma a identificar quais as raças do patógeno, que de fato existem no Brasil. A análise genética, foi feita com base na técnica de UPGMA, utilizando-se o coeficiente de similaridade de Jaccard. A técnica de GCV permitiu agrupar os isolados das Regiões Nordeste e Sudeste do Brasil no GCV 1 e os da Região Norte, no GCV 2. Enquanto que, o teste de patogenicidade permitiu determinar a presença da raça 1, através de sua patogenicidade em Gros Michel e da raça 4, em Grande Naine. Além de, agrupá-las dentro dos mesmos GCV

Chemical control of guava rust (Puccinia psidii) in the Northern Region of Rio de Janeiro State, Brazil.

Fungicides were evaluated under field conditions for their efficacy in the control of guava rust (Puccinia psidii); five systemic fungicides (azoxystrobin, pyraclostrobin, cyproconazole, tebuconazole, triadimenol) and the protectant mancozeb. In a first trial, the fungicides were applied at two-week intervals intercalated with bi-weekly sprays of copper oxychloride. The initial incidence of rust on flower buds before treatment was 47%. Triadimenol and azoxystrobin were most effective in reducing the incidence of rust on fruit. The minimum rust incidence achieved with triadimenol was 12% compared to 84% in the control treatment (water). The initial level of rust on flower buds was particularly high for the tebuconazole treatment, which may have contributed to the ineffective control by this fungicide in the first trial. In the second trial, copper oxychloride sprays were applied when disease incidence on flower buds was low (7%). Azoxystrobin, tebuconazole, triadimenol and mancozeb treatments were started nine days after a second application of copper oxychloride. The fungicides were then applied at bi-weekly intervals and at the same concentrations as in the first trial. Triadimenol was again most effective in controlling rust, although its effect did not greatly differ from that of tebuconazole. The maximum disease incidence in all fungicide treatments was significantly lower than that observed in the control treatment

Yield performance of half-sib families of physic nut (Jatropha curcas L.).

Among the oilseed plants, physic nut stands out for its yield potential and for the quality of its oil for biodiesel and biokerosene production. Currently, low seed yield, uneven fruit maturation and the lack of high yielding genotypes limit the viability of this crop. Here we evaluated the yield performance of a population, structured in 16 half-sib families, in the 2nd, 3rd and 4th years after planting (2009-11). Seed yield showed variability. The families maintained their relative performance over time. Contrary to expectations, seed yield was lower in the 4th year, probably due the increased competition between plants and leafhopper (Empoasca spp) incidence. Temporal yield stability and adaptability estimates indicated a trend toward maintaining plant superiority over time, and families 7 (1059 kg ha-1) and 12 (984 kg ha-1) showed the best stability and yield performance. Physic nut has the potential for greater yield gains

Biologia reprodutiva de pornunça (Manihot sp. - Euphorbiaceae) em área da Embrapa Semi-Árido, Petrolina-PE.

Com o objetivo de contribuir com informações sobre a biologia reprodutiva da espécie, o presente trabalho foi realizado na área da Embrapa Semi-Árido, PetrolinaPE (9º00? S, 40º22? W, 350 m de altitude) no período de janeiro a março 2003. As observações foram feitas em 12 indivíduos de Manihot sp., onde flores marcadas foram acompanhadas diariamente