6,572 research outputs found
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
An exploration of the Rape myths effect on the #MeToo movement acceptance in the UK
In the last few years, the global community saw the rise and later the fall of the #MeToo movement; an activist movement, which empowered survivors of sexual violence. Aiming to get a better understanding of the movement, this study explored how rape myths might be associated with the acceptance of the #metoo movement. Through an online survey, 76 participants from the UK, between 18 and 60 years old, responded to the Illinois Rape Myth Acceptance Scale – Revised and a short questionnaire on the #MeToo movement. Results showed there was a significant relationship between rape myth acceptance and negative perceptions of the #MeToo movement. Moreover, the subcategories of the IRMAS, ‘it wasn’t really rape’ and ‘she lied’, had the biggest relationship and effect on opinions about the #MeToo movement. This might suggest that dismissal and disregard of abusive acts, linked to gender stereotypes, is associated with the resistance towards the #metoo movement; which might lead to education and awareness about sexual violence
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 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 clÃnico 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 especÃficos com radiação tem contribuÃdo 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
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 contribuÃdo 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
Quantum error correction via noise guessing decoding
Quantum error correction codes (QECCs) play a central role in both quantum communications and quantum computation. Practical quantum error correction codes, such as stabilizer codes, are generally structured to suit a specific use, and present rigid code lengths and code rates. This paper shows that it is possible to both construct and decode QECCs that can attain the maximum performance of the finite blocklength regime, for any chosen code length when the code rate is sufficiently high. A recently proposed strategy for decoding classical codes called GRAND (guessing random additive noise decoding) opened doors to efficiently decode classical random linear codes (RLCs) performing near the maximum rate of the finite blocklength regime. By using noise statistics, GRAND is a noise-centric efficient universal decoder for classical codes, provided that a simple code membership test exists. These conditions are particularly suitable for quantum systems, and therefore the paper extends these concepts to quantum random linear codes (QRLCs), which were known to be possible to construct but whose decoding was not yet feasible. By combining QRLCs and a newly proposed quantum-GRAND, this work shows that it is possible to decode QECCs that are easy to adapt to changing conditions. The paper starts by assessing the minimum number of gates in the coding circuit needed to reach the QRLCs’ asymptotic performance, and subsequently proposes a quantum-GRAND algorithm that makes use of quantum noise statistics, not only to build an adaptive code membership test, but also to efficiently implement syndrome decoding.info:eu-repo/semantics/publishedVersio
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