Sharp upper estimates for the first eigenvalue of a Jacobi type operator

Our purpose in this article is to obtain sharp upper estimates for the first positive eigenvalue of a Jacobi type operator, which is a suitable extension of the linearized operators of the higher order mean curvatures of a closed hypersurface immersed either in the Euclidean space or in the Euclidean sphere.Brazilian National Research Council (CNPq): grant 303977/2015-9 y grant 308757/2015-7.peerReviewe

Characterizations of complete linear Weingarten spacelike submanifolds in a locally symmetric semi-Riemannian manifold

In this paper, we deal with n-dimensional complete spacelike submanifolds Mn with flat normal bundle and parallel normalized mean curvature vector immersed in an (n + p)-dimensional locally symmetric semi-Riemannian manifold L_p^(n+p) of index p obeying some standard curvature conditions which are naturally satisfied when the ambient space is a semi-Riemannian space form. In this setting, we establish sufficient conditions to guarantee that, in fact, p = 1 and Mⁿ is isometric to an isoparametric hypersurface of L_1^(n+1)having two distinct principal curvatures, one of which is simple.The first author is partially supported by CAPES, Brazil. The second author is partially supported by CNPq, Brazil, grant 303977/2015- 9. The fourth author is partially supported by CNPq, Brazil, grant 308757/2015-7.peerReviewe

Sharp upper estimates for the first eigenvalue of a Jacobi type operator

Our purpose in this article is to obtain sharp upper estimates for the first positive eigenvalue of a Jacobi type operator, which is a suitable extension of the linearized operators of the higher order mean curvatures of a closed hypersurface immersed either in the Euclidean space or in the Euclidean sphere.Brazilian National Research Council (CNPq): grant 303977/2015-9 y grant 308757/2015-7.peerReviewe

Crop rotation. V. Effect of winter crop on soybean productivity and yield components of direct drilled

Durante quatro anos, avaliaram-se a produtividade e os componentes do rendimento da soja em sucessão às culturas de inverno, em Passo Fundo, RS. A soja foi estabelecida em semeadura direta após algumas culturas de inverno. A semeadura e a colheita foram feitas mecanicamente, em parcelas de 120 m2. Os componentes do rendimento: número de legumes, número de grãos e peso de grãos por planta e, a produção da soja, foram pouco influenciados pelas culturas de inverno. Houve tendência de se obterem maiores produções de soja cultivada após a cevada e o trigo. O peso de 1.000 sementes, a altura de plantas e a população final mostraram menores valores na soja cultivada após a colza. Este fato parece dever-se ao retardamento da época de semeadura do que à cultura precedente.Soybean productivity and yield components in succession to winter crops was studied for four years at EMBRAPA/Centro Nacional de Pesquisa de Trigo, at Passo Fundo, RS, Brazil. Soybean was directly drilled into stubble of some winter crops and mechanically harvested in 120 m2 plots. Soybean yield and components such as number of grains and grain weight/plant were little influenced by the winter crops. There was a trend for soybeans to yield more when grown after barley and wheat. Soybean grown after rapeseed showed reductions on the 1,000-grain weight and final stand. This fact may be explained by seeding date rather than by the preceding winter crop

Cytotoxic and Antimicrobial Constituents from the Essential Oil of Lippia alba (Verbenaceae).

Backgroud:Lippia alba (Verbenaceae) is a plant widely used in folk medicine to treat various diseases. The present work deals with the chemical composition of the crude essential oil extracted from leaves of L. alba and evaluation of its antimicrobial and cytotoxic activities. Methods: Leaves of L. alba were extracted by hydrodistillation and analyzed by gas chromatography/mass spectrometry (GC/MS) as well as by nuclear magnetic resonance (NMR) spectroscopy. Cytotoxic and antimicrobial activities of crude essential oil were evaluated in vitro using MTT and broth microdilution assays, respectively. Results: Chemical analysis afforded the identification of 39 substances corresponding to 99.45% of the total oil composition. Concerning the main compounds, monoterpenes nerol/geraniol and citral correspond to approximately 50% of crude oil. The cytotoxic activity of obtained essential oil against several tumor cell lines showed IC50 values ranging from 45 to 64 µg/mL for B16F10Nex2 (murine melanoma) and A549 (human lung adenocarcinoma). In the antimicrobial assay, was observed that all tested yeast strains, except C. albicans, were sensitive to crude essential oil. MIC values were two to four-folds lower than those determined to bacterial strains. Conclusion: Analysis of chemical composition of essential oils from leaves of L. alba suggested a new chemotype nerol/geraniol and citral. Based in biological evidences, a possible application for studied oil as an antifungal in medicine, as well as in agriculture, is described

Transtorno bipolar do humor e gênero

Although the bipolar disorder (BD) occurs almost with the same frequency in both genders, the phenomenology and the outcome of the illness differ between them. Nevertheless, there is evidence that women with BD show, more than men, delayed beginning, especially in their fifth decade, more rapid cycling outcome, more depressive episodes, more dysphoric mania, more mixed states and more BD type II. Even so, the findings are not always consistent. Although the risk of comorbidities in BD includes, for both the sorts, excessive alcoholic consumption and drugs, bipolar men would have greater probability of being alcohol dependent, of not seeking treatment and of committing suicide. Suggested hypotheses to explain such differences vary from those centered in cultural or psychological aspects to those that focus on the steroids hormones, and other hormones such as cortisol, thyroid hormones and even on the cerebral anatomy. The reproductive cycle (menstrual cycle, pregnancy and menopause) influences on the BD phenomenology and its relevance to the therapeutical options in the treatment of the BD in women are presented in the last part of this review. Further investigations must to be done in order to clarify this controversy. However, up to now the data indicate that estrogen therapy is not to be primarily indicated to prevent depression, Alzheimer disease or cognition impairment.Embora o transtorno bipolar (TB) ocorra quase igualmente em ambos os sexos, a fenomenologia e o curso da doença diferem no homem e na mulher. No entanto, há evidências de que mulheres bipolares, mais que os homens, apresentariam início mais tardio (em especial na quinta década de vida), ciclagem rápida, mais episódios depressivos, mais mania disfórica que eufórica, estados mistos e evolução do tipo bipolar II, ainda que os achados nem sempre sejam consistentes. Embora o risco de comorbidades no TB inclua, para ambos os gêneros, abuso de álcool e drogas, homens bipolares teriam maior probabilidade de ser alcoolistas, não procurar tratamento e de se suicidar. Hipóteses sugeridas para explicar tais diferenças variam daquelas centradas em aspectos culturais ou psicológicos para as que focalizam os sistemas hormonais, como os esteróides gonadais ou o eixo tireoidiano, e até mesmo a anatomia cerebral. A influência do ciclo reprodutivo (ciclo menstrual, gravidez e menopausa) sobre as opções terapêuticas no tratamento do TB é apresentada na última parte desta revisão

Mapeando Dificuldades e Intervenções no Cotidiano das Organizações de Cultura Popular em Caruaru-PE

Neste texto, o objetivo é refletir sobre o cotidiano de organizações de culturas populares em Caruaru-PE, a partir de duas vivências: a primeira, referente ao mapeamento das principais dificuldades vividas por mestres(as), e a segunda, referente às intervenções realizadas. Partimos da noção de cotidiano de Michel de Certeau, para compreender as práticas táticas (ou microrresistências), e a premissa filosófica das práticas para a compreensão da realidade social. Realizamos conversas informais e entrevistas semiestruturadas com doze mestres(as) de onze diferentes segmentos da cultura popular e observações não participantes. Destacamos que as dificuldades mapeadas são expressões dos conflitos existentes no cotidiano dos(as) mestres(as), levando-os a realizar práticas táticas. Ademais, ressaltamos as ações de intervenção como possíveis microrresistências às práticas acadêmicas instituídas, capazes de se relacionar com as práticas das próprias organizações de culturas populares, criando “espaços” nos “lugares” instituídos, e constituindo o cotidiano

Agroecologia e justiça ambiental: um diálogo possível

O movimento por justiça ambiental surgiu nos EUA na década de 1970 quando pesquisas revelaram que os resíduos tóxicos eram destinados de forma desproporcional à populações afrodescendentes. A agroecologia, campo de produção científico interdisciplinar, também se consolidou na década de 1970, oriunda da fusão das ciências naturais e sociais, com o propósito de permitir o estilos de agricultura com maiores níveis de sustentabilidade, socialmente justa e economicamente viável. Esse trabalho situa-se no campo da pesquisa teórica, de caráter exploratório sobre as concepções e convergências da área da justiça ambiental e da agroecologia, utilizando-se de uma pesquisa bibliográfica com abordagem qualitativa. Ao fortalecer os modos de vida camponeses, a agroecologia tem contribuído na luta por justiça ambiental. Nesse sentido, podemos perceber a relação entre o movimento agroecológico e o movimento por justiça ambiental, dada suas convergências no objetivo de promover a justiça social.The movement for environmental justice emerged in the US in the 1970s when research revealed that toxic waste was allocated proportional to the Afro-descendant populations. Agroecology, interdisciplinary scientific production field, also consolidated in the 1970s, derived from the fusion of natural and social sciences, in order to allow the farming styles with higher levels of sustainability, socially just and economically viable. This work lies in the field of theoretical research, exploratory on the concepts and similarities of the area of environmental justice and agroecology, using a literature research with qualitative approach. By strengthening livelihoods farmers, agroecology has contributed in the struggle for environmental justice. In this sense, we can see the relationship between agro-ecological movement and the movement for environmental justice, given their convergence in order to promote social justice.Eje A6: Desarrollo Rural, Movimientos Sociales, Estado y AgroecologíaFacultad de Ciencias Agrarias y Forestale

Agroecologia e justiça ambiental: um diálogo possível

O movimento por justiça ambiental surgiu nos EUA na década de 1970 quando pesquisas revelaram que os resíduos tóxicos eram destinados de forma desproporcional à populações afrodescendentes. A agroecologia, campo de produção científico interdisciplinar, também se consolidou na década de 1970, oriunda da fusão das ciências naturais e sociais, com o propósito de permitir o estilos de agricultura com maiores níveis de sustentabilidade, socialmente justa e economicamente viável. Esse trabalho situa-se no campo da pesquisa teórica, de caráter exploratório sobre as concepções e convergências da área da justiça ambiental e da agroecologia, utilizando-se de uma pesquisa bibliográfica com abordagem qualitativa. Ao fortalecer os modos de vida camponeses, a agroecologia tem contribuído na luta por justiça ambiental. Nesse sentido, podemos perceber a relação entre o movimento agroecológico e o movimento por justiça ambiental, dada suas convergências no objetivo de promover a justiça social.The movement for environmental justice emerged in the US in the 1970s when research revealed that toxic waste was allocated proportional to the Afro-descendant populations. Agroecology, interdisciplinary scientific production field, also consolidated in the 1970s, derived from the fusion of natural and social sciences, in order to allow the farming styles with higher levels of sustainability, socially just and economically viable. This work lies in the field of theoretical research, exploratory on the concepts and similarities of the area of environmental justice and agroecology, using a literature research with qualitative approach. By strengthening livelihoods farmers, agroecology has contributed in the struggle for environmental justice. In this sense, we can see the relationship between agro-ecological movement and the movement for environmental justice, given their convergence in order to promote social justice.Eje A6: Desarrollo Rural, Movimientos Sociales, Estado y AgroecologíaFacultad de Ciencias Agrarias y Forestale