1,382 research outputs found

    Effective algebraic geometry and normal forms of reversible mappings

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    We present a new method to compute normal forms, applied to the germs of reversible mappings. We translate the classification problem of these germs to the theory of ideals in the space of the coefficients of their jets. Integral factorization coupled with Gr¨obner basis construction is the key factor that makes the process efficient. We also show that a language with typed objects like AXIOM is very convenient to solve these kinds of problems.We present a new method to compute normal forms, applied to the germs of reversible mappings. We translate the classification problem of these germs to the theory of ideals in the space of the coefficients of their jets. Integral factorization coupled with Gr¨obner basis construction is the key factor that makes the process efficient. We also show that a language with typed objects like AXIOM is very convenient to solve these kinds of problems

    Gestão de infestantes de inverno e primavera em vinha e olival com um fertilizante ecológico com propriedades herbicidas

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    Weeds reduce crop yields and require annual measures of control, although they can provide important ecological benefits. In this work, the efficacy was tested of an ecological fertilizer with herbicidal properties (Bioscrop Herbitec®) which in high concentrations (10-15%) can have a similar effect to a contact herbicide. The composition of the product is 6.0 % of water-soluble potassium oxide, 54.7 % of organic acids and 39.3 % of dispersants and diluents. The product was tested in six field trials during two years, which included two vineyards and two olive orchards and winter and spring vegetation. In each experiment three treatments were imposed, being the product applied at the concentrations of 10% and 15% and a non-treated control. In treated plots, the entire ground surface (rows and inter-rows) was sprayed. The evaluation of the effect of the treatments on vegetation was assessed by the pin point and grid methods which consisted of determining the percentage of damaged and not damaged vegetation and bare soil. The production of dry biomass of weeds was also evaluated as a measure of the persistence of the damage on vegetation. The floristic composition of the stands was also recorded to evaluate the specific susceptibility of the weeds to the different treatments. The results showed that the product severely damaged the vegetation, and the effect persisted for more than a month. The application of the product caused a severe reduction in the aboveground biomass while keeping the soil protected, showing a useful compromise between the reduction in weed competition and the maintenance of ground cover. Some species were severely damaged while others seemed to have benefited in relative terms, suggesting that the effectiveness of the product will be dependent on the weed species present.As infestantes reduzem a produtividade das culturas e requerem medidas anuais de combate, embora também possam fornecer importantes serviços ecossistémicos. Neste trabalho foi testada a eficácia de um produto ecológico (Bioscrop Herbitec®) que, em altas concentrações (10- 15%), pode ter um efeito semelhante ao de um herbicida de contato. O produto contém 6,0 % de óxido de potássio solúvel em água, 54,7 % de ácidos orgânicos e 39,3 % de dispersantes e diluentes. O produto foi testado em seis ensaios de campo, em duas vinhas e dois olivais e sobre vegetação de inverno e de primavera. Em cada ensaio foram testados três tratamentos, correspondentes à aplicação do produto em duas concentrações (10 e 15%) e uma modalidade testemunha. Nos talhões tratados o produto foi aplicado nas linhas e entrelinhas. O efeito dos tratamentos na vegetação foi avaliado pelos métodos do ponto quadrado e da grelha, que consistiram em determinar o grau de cobertura do solo com vegetação danificada, não danificada e solo nu. A produção de matéria seca das infestantes foi também avaliada como medida da persistência do dano na vegetação. A composição florística dos cobertos foi também registada como forma de avaliar a suscetibilidade específica das infestantes aos diferentes tratamentos. Os resultados mostraram que o produto danificou severamente a vegetação e o efeito persistiu por mais de um mês. A aplicação do produto causou uma redução significativa da biomassa aérea, mas manteve o solo protegido, mostrando um equilíbrio interessante entre a redução da competição das infestantes e a proteção do solo. Algumas espécies foram fortemente danificadas, enquanto outras parecem ter beneficiado em termos relativos, sugerindo que a eficácia do produto dependerá das espécies infestantes presentesThe authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013). The results of the first year of studies of this work were extracted from the master's thesis in Agroecology of the first author (António Barreira)info:eu-repo/semantics/publishedVersio

    A LINEAR STUDY OF HIGH-DRAG STATES AND FLOW STAGNATION PRODUCED BY MOUNTAIN WAVES

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    A linear model of gravity waves generated by stratified airflow over mountains is developed. The model provides simple, closed-form formulas for the surface drag in a situation where conditions for wave resonance exist. The wind is constant near the surface and decreases linearly above. The drag normalized by its value in the absence of shear is found to depend on two parameters: the height of the interface where the shear is discontinuous and the Richardson number, Ri, in the region above. This drag attains maxima when the height of the interface induces constructive interference between the upward and downward propagating reflected waves, and minima when there is destructive interference. The amplitude of the drag modulation becomes larger for lower Ri. It is also shown that, for Ri<2.25, the locations where wave breaking is first predicted to occur in flow over a 2D ridge become displaced horizontally and vertically by an amount depending on Ri

    Ictiofauna Da Bacia Do Rio Mundaú, Estado Do Ceará, Nordeste Do Brasil

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Mundaú river basin is located at Center-North Ceará State and occupies a total area of 2,227 km2, including Estuário do Rio Mundaú Environmental Protection Area. This study aimed to catalog the fishes of this basin. Collections were performed with active and passive gear in 35 sampling sites, between 2012 and 2014, in several habitats (main channels, streams, floodplains, permanent and temporary pools, ponds, and dams). A total of 2,545 specimens were collected, belonging to 55 species distributed in 10 orders, 31 families, and 50 genera; 30 of these are strictly freshwater species, and 25 estuarine-marine species. Three species (Hemigrammus guyanensis Gery, 1995, H. rodwayi Durbin, 1909 and Poecilia sarrafae Bragança &amp; Costa, 2011) represent new records for the Mid-Northeastern Caatinga ecoregion. Besides, two cynolebiid species, Hypsolebias sp. and Anablepsoides cearensis (Costa &amp; Vono, 2009), were found and the latter, currently classified as critically endangered, had its occurrence area widened. © 2017, Universidade Estadual de Campinas UNICAMP. All rights reserved.17123038.005584/2012-20, CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorFUNCAP, Fundação Cearense de Apoio ao Desenvolvimento Científico e TecnológicoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK‐cell subsets and its impact on the understanding of their tissue distribution and functional properties

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    Blood Cells Mol Dis. 2001 Jul-Aug;27(4):731-43. Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK-cell subsets and its impact on the understanding of their tissue distribution and functional properties. Lima M, Teixeira MA, Queirós ML, Leite M, Santos AH, Justiça B, Orfão A. Service of Clinical Hematology, Unit of Cytometry, Hospital Geral de Santo António, Porto, Portugal. [email protected] Abstract In the present study we have compared the immunophenotypic characteristics of the CD56+lo and CD56+hi NK-cell subsets in a group of normal healthy adults. Our results show that CD56+hi NK-cells display greater light-scatter properties than CD56+lo NK-cells at the same time they have higher levels of CD25 and CD122 IL-2 chains, together with a higher reactivity for HLA-DR and CD45RO and lower levels of CD45RA, supporting that, as opposed to the majority of the CD56+lo population, CD56+hi NK-cells might correspond to a subset of activated circulating NK-lymphocytes. Higher expression of the CD2 and CD7 costimulatory molecules found for the CD56+hi NK-cells would support their greater ability to respond to various stimuli. In addition, CD56+hi NK-cells expressed higher levels of several adhesion molecules such as CD2, CD11c, CD44, CD56, and CD62L compared to CD56+lo NK-cells, supporting a particular ability of these cells to migrate from blood to tissues and/or a potential advantage to form conjugates with target cells. Interestingly, CD56+lo and CD56+hi NK-cells showed a different pattern of expression of killer receptors that might determine different activation requirements for each of these NK-cell subsets. For instance, absence or low levels of CD16 expression might explain the lower antibody-dependent cytotoxicity activity of CD56+hi NK-cells. On the other hand, the virtual absence of expression of the CD158a and NKB1 immunoglobulin-like and the greater reactivity for the CD94 lectin-like killer receptors on CD56+hi in comparison to CD56+lo NK-cells might determine different MHC-class I specificities for both NK-cell subsets, a possibility that deserves further studies to be confirmed. PMID: 11778657 [PubMed - indexed for MEDLINE

    MENÇÕES SOBRE O ESTADO NUTRICIONAL. Nos Registos Clínicos de Doentes Hospitalizadosvo

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    Está descrito que a frequência de desnutrição associada à doença (DAD) afecta cerca de 30 a 60% dos doentes no momento da admissão hospitalar e cerca de 10% dos indivíduos na comunidade. A DAD tem vindo a ser associada a graves consequências, como ao maior risco de infecções e de disfunção de órgãos e a um aumento significativo, não só da morbilidade e mortalidade, como da frequência e dos custos com os cuidados de saúde. A falta do reconhecimento e da monitorização dos aspectos relacionados com o estado nutricional, têm sido apontados como factores que contribuem para o aumento da frequência de DAD, durante o internamento hospitalar. Foi objectivo deste estudo avaliar a relevância que é dada a aspectos relacionados com o estado nutricional dos doentes (peso, ingestão alimentar) e saber se os doentes em risco nutricional ou desnutridos serão alvo de maior atenção por parte dos profissionais de saúde. Foi recolhida uma amostra sistemática de seis hospitais portugueses, correspondente a 42-50% do total de camas de cada serviço de internamento. Foram critérios de exclusão a doença crítica, a gravidez, a idade inferior a 18 anos, a incapacidade de aplicação do protocolo de rastreio nutricional e o tempo de internamento inferior a 24h. Recolheram- se dados sócio-demográficos, antropométricos, sobre as menções dos processos clínicos respeitantes ao peso, cuidados alimentares/nutricionais prestados e ingestão alimentar/nutricional dos doentes e aplicou-se uma ferramenta de rastreio nutricional (Nutritional Risk Screening 2002). Em 1152 doentes estudados, a frequência de risco nutricional variou entre os 28,5% e 47,3%, enquanto que a frequência de desnutrição antropométrica oscilou entre 6,3% e 14,9%. Dois em cada três doentes tinha menções acerca de cuidados alimentares/ nutricionais prestados nos processos clínicos, mas apenas um em cada três tinha o seu peso medido e registado. Os doentes desnutridos foram pesados com menor frequência mas a sua alimentação e problemas a ela associados foram monitorizados com maior regularidade. A frequência de DAD, no momento de admissão hospitalar, é muito elevada, enquanto que a de menções relevantes para o estado nutricional é muito escassa. A presente investigação reforça a necessidade de investir na sensibilização dos profissionais de saúde, sobre a importância do rastreio e da prescrição/monitorização da alimentação e do peso dos doentes, na admissão e durante todo o internamento hospitalar

    GRAVITY WAVE DRAG PRODUCED BY SMALL AMPLITUDE ELLIPTICAL MOUNTAINS FOR SHEARED WIND PROFILES

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    The analytical models of Teixeira et al. (2004) and Teixeira and Miranda (2004), where the gravity wave drag exerted by a sheared stratified flow on axisymmetric or 2D mountains is calculated, are extended here to mountains with an elliptical horizontal cross section. For the simple situations considered in this study, the normalized drag depends on only two parameters: the Richardson number at the surface, Ri, and the horizontal aspect ratio of the mountain. For a wind that varies linearly with height, the drag always decreases as Ri decreases, albeit at different rates depending on the aspect ratio. For a wind that rotates with height at a constant rate maintaining its magnitude, the drag generally increases as Ri decreases, but if the mountain is sufficiently elongated in the surface streamwise direction, this dependence changes sign. It is also shown that flow stagnation at the surface is strongly affected by variations of the windspeed with height, but weakly affected by variations of wind direction

    Um magmatismo bimodal arqueano no âmbito dos complexos metamórficos do quadrilátero ferrífero e suas implicações tectônicas

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