Fitting isochrones to open cluster photometric data III. Estimating metallicities from UBV photometry

The metallicity is a critical parameter that affects the correct determination fundamental characteristics stellar cluster and has important implications in Galactic and Stellar evolution research. Fewer than 10 % of the 2174 currently catalog open clusters have their metallicity determined in the literature. In this work we present a method for estimating the metallicity of open clusters via non-subjective isochrone fitting using the cross-entropy global optimization algorithm applied to UBV photometric data. The free parameters distance, reddening, age, and metallicity simultaneously determined by the fitting method. The fitting procedure uses weights for the observational data based on the estimation of membership likelihood for each star, which considers the observational magnitude limit, the density profile of stars as a function of radius from the center of the cluster, and the density of stars in multi-dimensional magnitude space. We present results of [Fe/H] for nine well-studied open clusters based on 15 distinct UBV data sets. The [Fe/H] values obtained in the ten cases for which spectroscopic determinations were available in the literature agree, indicating that our method provides a good alternative to determining [Fe/H] by using an objective isochrone fitting. Our results show that the typical precision is about 0.1 dex

Combinations of Nitrogen and Sulphur for Signal Grass Yield

Signal grass (Brachiaria decumbens) is grown in Brazilian pastures, and the increase in forage yield of such pastures is achieved by fertilization. Nitrogen (N) is the nutrient mostly demanded for increasing grass productivity, and its utilization creates a demand for other nutrients, such as sulphur (S). These two nutrients are well related in plant metabolism, but the S nutrition of signal grass must be better understood. The use of a fractional factorial makes possible the study of several rates of these two nutrients, that combined with the response surface methodology allows anyone to find out the responses to these rates combinations. The objective of this research was to obtain the responses in dry matter yield of plant tops and roots of signal grass grown under N and S combinations

A importância da Comissão de Proteção contra Radiações no contexto da qualidade do Centro Hospitalar do Porto

Os meios complementares de diagnóstico e terapêutica transformaram-se em ferramentas essenciais para todos os ramos e especialidades da Medicina. Devido às suas propriedades únicas, a radiação ionizante apresenta múltiplas aplicações terapêuticas. Contudo, pode também originar potenciais danos para os utilizadores e para os pacientes. A quantificação da dose de radiação nos pacientes e o tempo de exposição dos procedimentos são uma preocupação crescente dos utilizadores. Este trabalho tem como objetivo apresentar a importância da Comissão de Proteção contra Radiações (CPCR) no contexto da qualidade do Centro Hospitalar do Porto (CHP). A CPCR detém múltiplas atividades, estando, atualmente, as suas sinergias direcionadas para a normalização do registo de dose no processo clínico dos pacientes e para a notificação, pelos Técnicos de Radiologia, dos eventos radiológicos contemplados nas normas pré--estabelecidas pela Comissão. A atribuição à CPCR da competência de identificação, acompanhamento e avaliação das exposições dos doentes a procedimentos específicos com radiação tem contribuído para reforçar a sensibilização dos profissionais para os valores de dose e os seus efeitos. A implementação dos procedimentos da Comissão permite assegurar um melhor acompanhamento dos doentes em risco, uma maior acuidade na monitorização das doses e uma otimização de protocolos.info:eu-repo/semantics/publishedVersio

Micronutrients in Grassland Production

Micronutrients, also known as trace minerals, which chiefly include boron (B), molybdenum (Mo), copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe), are required in extremely small quantities by crops and livestock. Their name, however, is not meant to imply their role is minor. Their lack, e.g., can cause serious crop production problems in forages and health disorders in livestock. This presentation includes the response of forage legumes and grasses to micronutrients, their deficiency and sufficiency levels in forages and their sufficiency levels in livestock. Forage legumes are more responsive to micronutrients, particularly B and Mo, than grasses. There are fewer documented cases of Cu, Fe, Mn and Zn deficiencies than of B and Mo deficiencies in forages. Soil acidity is one of the primary factors affecting the availability of micronutrients to forages. Low soil pH, e.g., is the principal cause of Mo deficiency in soybeans in Brazil and in a variety of crops in eastern Canada. More often soil properties and environmental factors are more important than actual soil levels, in affecting micronutrient availability. Micronutrient deficiencies have been emerging as a major problem in intensively cultivated soils in many countries and have become one of the serious constraints to crop productivity. Deficiency symptoms for most micronutrients appear on the young leaves at the top of the plant, because most of these nutrients are not readily translocated. However, Mo is an exception in that it is readily translocated, and its deficiency symptoms generally appear on the whole plant. Toxicity symptoms, on the other hand, for most micronutrients appear on the older leaves of the plant which is very striking, e.g., for B. Soil, foliar and seed applied methods of micronutrient application to control their deficiency are discussed in detail. Frequently the Cu, Fe, Mn, Zn and Se levels in forages which are sufficient for optimum crop yields are not adequate to meet the needs of livestock. Selenium is a trace mineral which is not required by plants and maximum forage yields can be obtained on soils with very low amounts of soil Se. However, if animals are fed forage with low Se, they could suffer from serious muscular disorders and other diseases. White muscle disease caused due to Se deficiency is the most common disorder and is found in calves and lambs. Sufficiency levels of micronutrients for crops have been discussed in relation to the animal requirement

A importância da Comissão de Proteção Contra as Radiações no contexto do Centro Hospitalar do Porto

A procura pela qualidade nos serviços de saúde deixou de ser um ato isolado e tornou-se hoje um dado adquirido e categórico. Uma Sociedade cada vez mais exigente, no que à qualidade dos serviços prestados diz respeito, levou à criação de normas e mecanismos de avaliação e controlo da qualidade nos serviços de saúde. Os meios complementares de diagnóstico e terapêutica imagiológicos transformaram-se em ferramentas essenciais para todos os ramos e especialidades da medicina e a sua crescente utilização tem contribuído para um aumento da dose de radiação nos pacientes, tornando-se numa preocupação constante dos utilizadores. A quantificação e monitorização da dose permite assegurar a segurança dos pacientes, assim como contribuir para a manutenção de serviços de qualidade no SNS. Este trabalho, fundamentado numa revisão da literatura especializada, visa demonstrar a importância da Comissão de Proteção contra Radiações (CPCR), no contexto do Centro Hospitalar do Porto, na manutenção da qualidade e segurança de todos os pacientes e profissionais envolvidos em procedimentos radiológicos.info:eu-repo/semantics/draf

Simulation of VUV electroluminescence in micropattern gaseous detectors: the case of GEM and MHSP

Electroluminescence produced during avalanche development in gaseous avalanche detectors is an useful information for triggering, calorimetry and tracking in gaseous detectors. Noble gases present high electroluminescence yields, emitting mainly in the VUV region. The photons can provide signal readout if appropriate photosensors are used. Micropattern gaseous detectors are good candidates for signal amplification in high background and/or low rate experiments due to their high electroluminescence yields and radiopurity. In this work, the VUV light responses of the Gas Electron Multiplier and of the Micro-Hole Strip Plate, working with pure xenon, are simulated and studied in detail using a new and versatile C++ toolkit. It is shown that the solid angle subtended by a photosensor placed below the microstructures depends on the operating conditions. The obtained absolute EL yields, determined for different gas pressures and as functions of the applied voltage, are compared with those determined experimentally.Comment: Accepted for publication in Journal of Instrumentatio

Leaf Appearance Rate in \u3ci\u3eBrachiaria decumbens\u3c/i\u3e Grown in Nitrogen and Potassium Rates

A greenhouse experiment was carried out with Brachiaria decumbens Stapf. cv. Basilisk grown in nutrient solution. Five nitrogen rates (42; 140; 238; 336 and 434 mg/L) and three potassium rates (78; 234 and 390 mg/L) were studied in a factorial experiment, in a randomized complete block design, with four replications. Green leaf number was evaluated in six times in the first period of growth (27, 30, 33, 36, 39 and 42 days after transplanting) and nine times in the second period (45, 48, 51, 54, 57, 60, 63, 66 and 69 days after transplanting). Data was registered in three plants per pot. The average green leaf number per tiller changed significantly (P\u3c 0.01) with nitrogen rates in the two growth periods. Leaf appearance rate was higher at nitrogen rates of 336 or 434 mg/L