7 research outputs found

    Alley Cropping and Green Manuring For Upland Crop Production in West Sumatra

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    Green manuring and alley cropping were studied as means of improving crop production and reducing lime requirements in Sitiung, West Sumatra. Two experiments were conducted between 1985 and 1988 on acid, high aluminum soil (pH of 4.2 to 4.7 and Al+H saturation of 70 to 90 %). Low levels of external inputs were used in these experiments. In the alley cropping experiment, three tree species Paraserianthes falcataria. Calliandra calothvrsus, and Gliricidia sepium and a no tree control were compared as well as three lime rates of zero, 750 kg ha-1, and liming to 25% Al+H saturation. Paraserianthes and Calliandra both grew vigorously (producing about 3 T leaf ha-1 year-1) and showed no consistent response to lime, even at Al+H saturations of greater than 70%. Gliricidia grew poorly (producing about 0.5 T leaf ha-1 year-1) with growth especially limited at high soil Al+H saturation. Upland rice (Orvza satival and cowpea (Viona unquiculatal crops responded to both lime and green leaf manure (GLM) application. Paraserianthes GLM application doubled rice yields and quadrupled cowpea yields as compared to control plots. However, overall yields declined over the study period, possibly due to increasingly sporadic rainfall distribution. Also, Paraserianthes hedges began to die after four years while Calliandra hedges remained vigorous. Ongoing studies are needed to evaluate sustainability. Economic analyses procedures were developed for comparing alley cropping and liming practices. The Paraserianthes + Low lime rate treatment was shown to be most profitable. If lime is not available, alley cropping with Paraserianthes may be more profitable than farmer’s current practices. In the second experiment, Crotalaria usaramoensis. Calopogonium mucunoides and Centrosema pubescens were grown as green manure crops during two dry seasons and were applied to a rotation of upland rice or maize followed by peanuts. Upland rice did not respond to either liming or green manure application, probably because it is tolerant of high soil acidity. Subsequent maize (Zea mays) and peanut (Arachis hvpoqaea) growth increased with liming, but overall there was little yield increase due to green manure application and little or no increase with inorganic N application. Therefore, the value of herbaceous green manures is questionable in farming systems in Sitiung, while alley cropping may have potential for improving crop yields on limited resource farms

    Avaliação do desempenho das envolventes dos edifícios face à acção dos sismos

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    Tese de doutoramento em Engenharia CivilA envolvente dos edifícios em Portugal é constituída quase exclusivamente por paredes de alvenaria, que têm principalmente a função de vedação. Apesar de não terem função estrutural, as paredes ao interagirem com a estrutura, condicionam o comportamento sísmico dos edifícios, exigindo-se-lhe sob esta óptica, um desempenho adequado, evitando a ocorrência de danos severos nas paredes no seu plano, que conduzam a perdas económicas graves, e o colapso das paredes para fora do plano, que poderão colocar em perigo vidas humanas. Os actuais regulamentos estruturais europeus, no que concerne à segurança sísmica das estruturas exigem a verificação da segurança de elementos não estruturais quando o seu colapso acarreta riscos para pessoas ou para a estrutura principal. Os Eurocódigos estruturais quando entrarem na fase de implementação obrigatória irão impor novas exigências que deverão ser cumpridas pelos edifícios ou pelas suas partes. Tal é o caso das alvenarias de preenchimento, que deverão resistir ao movimento para fora do plano imposto pela acção dos sismos, devendo ser tomadas medidas adequadas para evitar a rotura prematura e desintegração das paredes de preenchimento, bem como, o colapso parcial ou total para fora do plano de painéis de alvenaria. A análise dos edifícios construídos nos últimos vinte anos, concebidos de acordo com os padrões modernos, pode conduzir a conclusões preocupantes. Imagens de expulsões para fora do plano e danos severos no plano de paredes de preenchimento, em recentes actividades sísmicas em todo o mundo, fizeram sentir aos engenheiros as consequências da má prática construtiva, das soluções erradas ou projecto inadequado das estruturas. Este trabalho tem como objectivo principal a avaliação do comportamento das paredes de preenchimento em alvenaria face à acção sísmica, enfatizado na procura da resposta de questões relativas: à caracterização dos tipos de estrutura e envolventes dos edifícios recentes; à avaliação das propriedades dos materiais constituintes das envolventes; à avaliação do comportamento das envolventes actuais, bem como, de novas soluções de envolvente, quando solicitadas pela acção dos sismos; à proposta de técnicas de reforço ou de reabilitação das envolventes; e à obtenção de ensinamentos para o projecto de edifícios novos. Para atingir os objectivos traçados, foi realizada a caracterização do parque habitacional português, com enfoque na tipologia da envolvente e da estrutura, tendo em vista a definição dos edifícios alvo do estudo. Da caracterização destes edifícios, resultou: um modelo que representa o património edificado em Portugal desde a década de 80 do século passado, com estrutura de betão dimensionada seguindo a actual regulamentação nacional e a envolvente de parede dupla, constituída por dois panos de alvenaria rebocados nas faces exteriores; e dois modelos, representando possíveis soluções de futuro, com estrutura de betão dimensionada seguindo a normativa europeia e envolvente constituída por um pano de alvenaria simples de tijolo rebocado em ambas as faces, ou com as juntas de assentamento armadas ou com o pano revestido em ambas as faces por reboco armado. Na prossecução dos objectivos indicados, após a caracterização dos edifícios alvo, foi realizada uma investigação experimental seguindo três vectores: a determinação das propriedades das alvenarias e dos seus componentes; a avaliação do comportamento dos painéis de alvenaria para fora do plano quando sujeitos a dano prévio no plano; e a avaliação do comportamento dos edifícios alvo sujeitos a ensaios dinâmicos em mesa sísmica. Para esclarecimento dos resultados obtidos pela via experimental, foram realizados estudos paramétricos na procura de modelos analíticos simples que pudessem descrever o comportamento no plano e para fora do plano das paredes de preenchimento, permitindo deste modo prever a sua capacidade resistente, para diversas soluções construtivas e de geometria Da investigação realizada foi concluído que na resposta mecânica no plano dos painéis de alvenaria quando solicitados horizontalmente é possível estabelecer uma sequência de dano relacionada com a curva de capacidade do painel, verificando-se que, geralmente, são os interfaces os principais responsáveis pela entrada do painel em regime não linear, seguindose- lhe o dano observado na zona corrente da alvenaria, variando entre a fendilhação diagonal e o esmagamento dos cantos superiores, e por fim, a rotura das ligações da viga com o pilar. Por outro lado, para fora do plano, a solução construtiva não rebocada foi a que apresentou a menor resistência do conjunto dos painéis ensaiados. As soluções construtivas de alvenaria com reboco armado e de alvenaria rebocada com juntas de assentamento armadas, foram aquelas que apresentaram as maiores capacidades resistentes, sendo este acréscimo de resistência conseguido à custa do reboco e da armadura. Em situação intermédia ficaram as soluções de parede dupla rebocada nas faces exteriores dos panos. Da investigação experimental realizada na mesa sísmica foi concluído que o modelo com a estrutura de betão armado dimensionada com recurso à actual regulamentação nacional, com uma envolvente constituída por dois panos rebocados de alvenaria, teve um comportamento sísmico claramente inferior aos modelos dimensionados segundo a regulamentação europeia, com a envolvente constituída por alvenaria simples rebocada e armada. O trabalho de investigação permitiu também, o desenvolvimento de uma metodologia de dimensionamento, apoiada nos resultados obtidos e na pesquisa realizada acerca do estado da arte, relativamente ao comportamento dos painéis no plano e para fora do plano que poderá servir de base para a verificação da estabilidade em projectos de edifícios novos ou a reabilitar.The building envelope in Europe is usually made of masonry walls, with enclosure and infill functions. Masonry walls have a major economic importance and contribute significantly to the building performance. Even if infill walls have no load-bearing function, they contribute significantly to the seismic behavior of buildings. Therefore, their adequate structural performance is needed, avoiding the occurrence of severe in-plane damage, with very large economic losses, and the out-of-plane expulsion, which additionally represents a large hazard for human life. Recent earthquake codes in Europe require the safety assessment of non-structural elements (parapets, veneer masonry walls, infill walls, etc.), when their collapse entails danger for people or for the main structure. The Eurocode standards, entering the mandatory stage now, incorporate new requirements to be fulfilled by buildings or their parts. Such is the case of masonry infilled RC frames whose panels, according to Eurocode 8, are explicitly required to withstand the out-of-plane movement induced by earthquakes. Appropriate measures should be taken to avoid brittle failure and premature disintegration of the infill walls, as well as the partial or total out-of-plane collapse of slender masonry panels. The analysis of buildings constructed in the last 20 years, designed following modern standards, may lead to worrying conclusions. Images of out-of-plane expulsions and severe in-plane damage of infill walls in recent seismic activities around the world reminded engineers of the consequences of bad practice, wrong solutions or inadequate design. This work presents the experimental work and results achieved by applying cyclic out-of-plane loads to damaged masonry infilled RC frames. The masonry panels were previously damaged by applying an in-plane cyclic load after which the cyclic out-of- plane loads were applied. The frames and panels tested follow the traditional Portuguese RC structure construction system to which different types of reinforcement have been introduced in the panels. In order to achieve the proposed goals a residential building characterization was carried out in Portugal and it has focused in the buildings envelope and its structure so that representative samples could be studied. As a result, three models were built: a model which represents the Portuguese traditional buildings since the nineteen-eighties which has a reinforced concrete structurale design according to present codes and cavity walls plastered as envelope solution; two models designed according to European legislation which aim to be a future solution where both are reinforced concrete frame with infilled masonry with either bed joint reinforcement or masonry infilled panels with external reinforcement. An experimental campaign was carried out in order to determine: the masonry properties; outplane panel behavior with previous in-plane damage; and building behavior subjected to dynamic tests performed in the shaking table. Parametric tests were also conducted, to establish analytical models able to reproduce in-plane and out-plane behavior leading to an estimated load bearing capacity for each model. It was concluded that panels subjected to horizontal in-plane loads got a damage condition correlated to the load bearing panel capacity. It was noticed that the interfaces masonry/concrete behavior leads the panel to the nonlinear stage and thereafter masonry cracks in diagonal patterns occur and corners got crushed, until column and beam connection finally fails. For the out-plane tests, traditional walls had the weaker performance and both reinforced solutions had higher loadbearing capacity. From the dynamic experimental campaign performed in the shaking table it was concluded that the traditional walls had clearly a weaker resistance than the reinforced models designed according to the European coded. These studies also made possible the development of a design method, supported by the presented results and in-plane and out-plane behavior of reinforced concrete frames with masonry infill state of the art, can be used to verify the masonry infill stability

    A importância da Ria Formosa no ciclo biológico de Solea senegalensis Kaup 1858, Solea vulgaris Quencel 1806, Solea lascaris (Risso, 1868) e Microchirus azevia (Capello, 1868)

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    Tese de Doutoramento, Biologia Marinha, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Universidade do Algarve, 1990Existe actualmente unanimidade sobre a posição de relevo que a Ria Formosa asssume entre as formaçOes lagunares da costa portuguesa. Este aspecto resulta não só da importância económica das inúmeras actividades aí desenvolvidas, mas também encerra razões de índole cientifica que têm atraído, de modo crescente, a atenção da comunidade científica internacional

    The ionized gas in active galaxies in the MaNGA survey

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    Apresentamos mapas para as distribuições de fluxo nas linhas de emissão, excitação, densidade superficial de massa de gás ionizado e taxa de formação estelar para 150 Núcleos Ativos de Galáxias (AGN) observados com o SDSS-IV MaNGA, comparando-os com os obtidos para uma amostra controle de galáxias não ativas. Descobrimos que, para os AGNs early-type, o gás ionizado é mais concentrado na região nuclear quando comparado com as galáxias de controle, enquanto que para as galáxias late-type a distribuição de gás é semelhante à das galáxias de controle, sendo distribuída mais uniformemente por todo a galáxia. A massa total de gás ionizado varia de ≈ 104M a ≈ 109M. A principal diferença entre os AGNs e os controles está na densidade superficial central de massa de gás ionizado { dentro de 0,2R Re (raio efetivo) { que é maior para os AGNs do que para os controles, com uma diferença maior observada para as early-types do que para as late-types. Essa diferença entre os AGNs e os controles é maior para os AGNs de maior luminosidade e torna-se mais baixa à medida que a luminosidade dos AGNs diminui. Calculamos os perfis espaciais médios da densidade superficial de massa de gás ionizado e mostramos que eles decrescem mais rapidamente com o raio para os AGNs do que para os controles dentro de 0,4R e no caso dos AGNs de maior luminosidade (L([OIII]λ 5007) ≥ 3:8x1040 erg s-¹)sendo semelhantes aos dos controles além deste raio e para AGNs de menor luminosidade. Calculamos a taxa de formação estelar SFR nas regiões HII do corpo das galáxias hospedeiras de AGN e controles, encontrando uma diferença somente para as galáxias early-type, para as quais as que têm AGN apresentam um pequeno excesso no valor da SFR em relação às galáxias de controle. Estudamos também a relação entre o raio RNLR (onde NLR é a sigla para representar a Narrow Line Region) da região ionizada pelo AGN e a luminosidade L[OIII] do AGN e encontramos uma correlação positiva. Esta correlação indica que a região de gás ionizado pelo AGN cresce com a luminosidade do mesmo, de forma semelhante à encontrada previamente para a Broad Line Region e por outros autores para a NLR. Finalmente, obtivemos a metalicidade do gás para as regiões HII no corpo da galáxia que, extrapolada para a região central, mostra um bom acordo com a metalicidade derivada para o gás da NLR a partir de calibrações em termos de razões de linhas de emissão obtidas a partir de modelos de fotoionização.We present maps for the ionized gas density and star formation rates for 150 Active Galactic Nuclei (AGN) observed with SDSS-IV MaNGA, and compare them with those of a control sample of nonactive galaxies. We nd that, for the early-type AGN, the ionized gas is more concentrated in the nuclear region, when compared with the controls, while for the late-type galaxies the gas distribution is similar to that in the controls, being spread throughout the galaxies. The total ionized gas mass ranges from ≈ 104M to ≈109M . The main difference between the AGN and controls is on the central ionized gas surface mass density { within 0.2Re (effective radius) { that is larger for the AGN than for the controls, with a larger difference observed for the early-type than for the late-type galaxies. This di#erence between the AGN and controls is highest for the highest luminosity AGN and becomes lower as the AGN luminosity decreases. We have calculated average proles of the gas surface mass density and show that they are steeper in the AGN when compared to controls within the inner 0.4Re for the highest luminosity AGN (L([OIII]λ 5007) ≥ 3:8 x 1040 erg s1), being similar to those of the controls beyond this radius and for lower luminosity AGN. We have obtained the star-formation rate SFR for the HII regions along the body of the AGN host galaxies and controls, nding a di#erence only for the early-type galaxies, for which the AGN hosts present a small excess in the integrated SFR as compared to the control galaxies. We have also investigated the relation between the radius of the region ionized by the AGN RNLR (where NLR stands for Narrow- Line Region) and the AGN luminosity L[OIII], finding a positive correlation. This correlation indicates that the radius of the region ionized by the AGN increases with its luminosity, similarly to previously found for the Broad-Line Region and for the NLR itself in previous studies. Finally, we have derived the gas metallicity for the HII regions over the body of the galaxy that, when extrapolated to the central region, shows good agreement with the gas metalicity of the NLR obtained from calibrations in terms of emission-line ratios derived from photoionization models

    Mitochondrial control of gene expression and extrinsic apoptosis

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    Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de la Materia Condensada. Fecha de lectura: 23-04-2019Even under homogeneous environmental conditions, cells with identical genotypes can display significant variations at the phenotypic level, that is, di erences in size, morphology and internal state. This is a result of the genetic and signaling circuits that control cellular functions being subject to fluctuations in the levels of their components. Cell-to-cell variability is regarded as an essential agent in many key cellular activities such as development, di erentiation, evolution, virus infection or cell death, and has been shown to serve a biological function in many cases. Thus, tracing back its sources is central to understand the behaviors of individual cells and ultimately act on them. In this work we use a combination of experimental, mathematical and computational tools to investigate the role of mitochondria (the main energy provider in eukaryotic cells) on the generation of gene expression noise. Gene expression is highly energy demanding and in turn determines phenotype, pointed as the cause of variable individual cellular responses in several processes, notably apoptosis. Heterogeneity in apoptotic outcomes is particularly relevant as it poses the main cause of tumor resistance to chemotherapy. Our results highlight the importance of mitochondria as a global modulator of gene expression, but also reveal its role regulating complex, non-linear processes like alternative splicing. We found that this control of gene expression is specially important in the apoptotic signaling pathway: mitochondria exhibit the power to discriminate apoptotic fates at the single cell level, making it a good candidate for a biomarker of the susceptibility of cancer cells to death-inducing treatments. iIncluso en condiciones ambientales homog´eneas, c´elulas con genotipos id´enticos pueden presentar variaciones significativas a nivel fenot´ıpico, es decir, diferencias en tama˜no, morfolog´ıa y estado interno. Esto es el resultado de los circutos gen´eticos y de se˜nalizaci´on que controlan la funci´on celular estando sometidos a fluctuaciones en los niveles de sus componentes. La variabilidad de c´elula a c´elula es considerada un agente esencial en multitud de actividades celulares como el desarrollo, diferenciaci´on, evoluci´on, infecci´on v´ırica o la muerte celular. Por tanto, identificar sus fuentes es central para entender los comportamientos de c´elulas individuales y en ´ultima instancia actuar sobre ellos. En este trabajo utilizamos una combinaci´on de herramientas experimentales, matem´aticas y computacionales para investigar el papel de la mitocondria (principal proveedor de energ´ıa en c´elulas eucariotas) en la generaci´on de ruido en expresi´on gen´etica. La expresi´on gen´etica es costosa energ´eticamente y determina el fenotipo, se˜nalado en muchos procesos como causa de la variabilidad en las respuestas de c´elulas individuales, en particular en el de apoptosis. La heterogeneidad en los resultados apopt´oticos es particularmente relevante porque supone la principal causa de resistencia de tumores a quimioterapia. Nuestros resultados resaltan la importancia de la mitocondria como modulador global de la expresi´on g´enica, pero tambi´en revelan su papel regulando procesos complejos y no lineales como el splicing alternativo. Encontramos que este control de la expresi´on g´enica es especialmente importante en la ruta de se˜nalizaci´on apopt´otica: la mitocondria muestra el potencial de discriminar destinos apopt´oticos a nivel de c´elula ´unica, convirti´endola en un buen candidato a biomarcador de la susceptibilidad de c´elulas cancer´ıgenas frente a tratamientos inductores de apoptosis

    Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food

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    EFSA wishes to thank the Working Group members: Manolis Kogevinas (until 14 September 2016), George Loizou (until 23 January 2017), and the hearing experts: Matteo Bonzini, Jane Burns, Claude Emond, Aleksander Giwercman, Russ Hauser, Lidia Mínguez‐Alarcón and Paolo Mocarelli, for the support provided to this scientific output. The CONTAM Panel acknowledges all European competent institutions and other stakeholders that provided occurrence data on PCDD/Fs and DL‐PCBs in food and feed, and supported the data collection for the Comprehensive European Food Consumption Database.Peer reviewedPublisher PD

    Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food

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    The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.Peer reviewe
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