Biaxial seismic behaviour of reinforced concrete columns

Please consider this abstract to be included in the PhD OlympiadsInternational audienceThe present work focuses on the assessment of the structural response of RC columns under bidirectional horizontal loads in three main streamlines. First, an experimental testing campaign was performed on rectangular columns, for different types of loading. Subsequently, the tested columns were simulated with different non-linear modelling strategies. Finally, a simplified hysteretic model is proposed for the representation of the non-linear response of RC members subjected to biaxial bendin

CARACTERIZAÇÃO E ANÁLISE DOS ENTRAVES DA ATIVIDADE APÍCOLA MARANHENSE

O texto tem como objetivo geral apresentar uma discussão de como se estabelece a atividade econômica da apicultura no Estado do Maranhão, desenvolvendo uma análise das suas potencialidades e entraves centrais. De acordo com os resultados apresentados ainda não se pode efetivamente afirmar a existência de uma cadeia produtiva do mel no estado, considerando especialmente o baixo nível de organização dos produtores, baixa capacidade de beneficiamento do produto, não inserção no mercado externo, considerando também que existe uma grande saída de parte do mel coletado no estado para outras unidades da federação, especialmente Piauí e Santa Catarina. Assim, podemos citar dentre os fatores que inviabilizam um melhor desenvolvimento da atividade produtiva no Maranhão, destacam-se: o baixo nível de organização institucional; incipientes formas de organização associativa/cooperativa; baixo grau de capacitação dos produtores (devido principalmente à falta de um acesso mais efetivo à assistência técnica); fiscalização deficiente (relacionada aos apicultores migratórios); e especialmente dificuldades no processo de beneficiamento da produção local.</jats:p

Caracterização térmica e hídrica da cultura do feijão-de-vagem na região da Grande Florianópolis

The study aimed to determine the basal temperature, the heat units and the irrigation moment in snap beans growing, in order to provide optimal water supply. Two variety groups were used: "macarrão" and "manteiga", sowed at ten different periods spaced approximately 20 days. The experiment was designed in blocks (bands) with four replicates in each sowing period. Temperature, relative humidity and rain were measured. The matricial potential of the soil water was determined by tensiometers installed at 10 cm depth. Phenological observations and radicular and foliar sampling were made, and the foliar area index was estimated. The heat units were estimated through the Degree-Days method, in which the basal temperature was estimated by the interception of X axis. The results showed that the basal temperature between sowing and first harvest was 7.03 °C and 6.35 °C for "macarrão" and "manteiga", respectively. Their heat sums were 954 and 1015 Degree-Days, respectively. In relation to the irrigation moment it was observed that until the third trifoliate leaf appearance, matricial potential accused irrigation requirement at about -0.015 MPa, decreasing to -0.025 MPa at the beginning of flowering, and falling bellow -0.030 MPa during harvest.O estudo teve por objetivo determinar a temperatura basal, as somas térmicas e o momento de irrigação da cultura do feijão-de-vagem (Phaseolus vulgaris L.). Foram realizados plantios em dez épocas, com intervalo de 20 dias entre épocas, sendo dois os grupos envolvidos: "macarrão" e "manteiga". O delineamento experimental utilizado foi em faixas, com quatro repetições dentro de cada época de plantio. Os elementos meteorológicos medidos foram temperatura do ar, umidade relativa do ar e precipitação pluvial. O potencial de água no solo foi medido por tensiômetros instalados à profundidade de 10 cm. Observações fenológicas foram feitas juntamente com amostragem do sistema radicular e de área foliar, estimando-se em seguida o índice de área foliar. As somas térmicas foram estimadas pelo método graus-dia, e a temperatura basal, pelo método de interceptação do eixo X. Os resultados mostraram que os valores de temperatura basal obtidos no período do plantio até a primeira colheita foram 7,03 °C e 6,35 °C em relação aos grupos "macarrão" e "manteiga", e as somas térmicas, 954 e 1015 graus dias, respectivamente. Com relação ao momento de irrigação, verificou-se que até o período da terceira folha trifoliolada o potencial matricial que acusava a necessidade de irrigação era cerca de -0,015 MPa, e caiu para -0,025 MPa no início do florescimento, e abaixo de -0,030 MPa no período da colheita

Surface expression of an immunodominant malaria protein B cell epitope by yellow fever virus

The yellow fever 17D virus (YF17D) has several characteristics that are desirable for the development of new, live attenuated vaccines. We approached its development as a vector for heterologous antigens by studying the expression of a humoral epitope at the surface of the E protein based on the results of modelling its three-dimensional structure. This model indicated that the most promising insertion site is between beta-strands f and g, a site that is exposed at the external surface of the virus. the large deletion of six residues from the fg loop of the E protein,, from yellow fever virus, compared to tick-born encephalitis virus, leaves, space at the dimer interface for a large insertion without creating steric hindrance. We have tested this hypothesis by inserting a model humoral epitope from the circurnsporozoite protein of Plasmodium falciparian consisting of triple NANP repeats. Recombinant virus (17D/8) expressing this insertion flanked by two glycine residues at each end, is specifically neutralized by a monoclonal antibody to the model epitope. Furthermore, mouse antibodies raised to the recombinant virus recognize the parasite protein in an ELISA assay. Serial passage analysis confirmed the genetic stability of the insertion made in the viral genome and the resulting 17D/8 virus is significantly more attenuated in mouse neurovirulence tests than the 17DD vaccine. the fg loop belongs to the dimerization domain of the E protein and lies at the interface between monomers. This domain undergoes a low pH transition, which is related to the fusion of the viral envelope to the endosome membrane. It is conceivable that a slower rate of fusion, resulting from the insertion close to the dimer interface, may delay the onset of virus production and thereby lead to a milder infection of the host. This would account for the more attenuated phenotype of the recombinant virus in the mouse model and tower extent of replication in cultured cells. the vectorial capacity of the yellow fever virus is being further explored for the expression and presentation of other epitopes, including those mediating T-cell responses. (C) 2002 Academic Press.Fdn Oswaldo Cruz, Inst Oswaldo Cruz, Dept Bioquim & Biol Mol, BR-21045900 Rio de Janeiro, BrazilUniv São Paulo, Inst Fis Sao Carlos, BR-13566590 Sao Carlos, SP, BrazilFdn Oswaldo Cruz, Inst Tecnol Imunobiol, Dept Desenvolvimento Tecnol, BR-21045900 Rio de Janeiro, BrazilEscola Paulista Med, Dept Microbiol Parasitol & Imunol, BR-04023062 São Paulo, BrazilNYU, Sch Med, Dept Med & Mol Parasitol, New York, NY 10010 USAEscola Paulista Med, Dept Microbiol Parasitol & Imunol, BR-04023062 São Paulo, BrazilWeb of Scienc

Seismic behavior of RC building structures designed according to current codes

Earthquakes which recently occurred in highly populated regions show that existing buildings constructed without appropriate seismic resisting characteristics may constitute as an important source of risk and may cause economical loses and casualties. It is recognized the progress of the knowledge in earthquake engineering in the last decades. In this paper, two 6 irregular storey buildings were studied consisting of frame structures, representative of the common practice in Portugal, i.e. designed without considering earthquake actions. Push-over and non-linear time history analyses were done, with non-linear 3-D models in longitudinal and transverse directions. The building responses were analyzed in two different levels: global and local. For the global response analyses: max displacement, inter-storey drift (IS drift), floor rotation for each storey and base shear were compared. For local response four columns were chosen and the variation of axial load in terms of base shear and drift as well as the biaxial demand was considered. The result shows that most variation of axial load happens in corner, facade-X, facade-Y and centre column respectively. It is noteworthy that by increasing the initial axial load the biaxial demand decreases. The seismic vulnerability was analyzed for earthquake of different return periods, and the seismic demands were compared with limit proposed in international codes and conclusion are drafted in terms of safety. The vulnerability assessment based on seismic codes clearly shows that the building 2 presented a better performance with low inter-storey drifts. The main goal of this study is considering the application and methodology for the seismic assessment of existent real buildings. In fact this is an important topic, to understand the seismic vulnerability of certain particularities in existing buildings to assure that the common observation can be applied for a prototype building, especially irregular ones. Also one of the major observations in this study is the comprehension of the effect and importance of biaxial loading in columns and the influence of the axial load variation, relating the position of the columns in plan and in height