207 research outputs found

    Comportamento do emprego formal na agropecuária da região sul do Brasil entre os anos de 2006 e 2015

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    TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Agrárias. Curso de Agronomia.A agropecuária tem significativa participação no PIB e nas exportações brasileiras. O aumento da produtividade dos principais produtos agrícolas produzidos no País pelo processo de mecanização e adoção de tecnologia no sistema de produção levou o Brasil a se tornar um dos mais competitivos no cenário internacional, entretanto, provocou mudanças nas relações de trabalho. O objetivo deste trabalho foi avaliar o comportamento do emprego formal no setor nos últimos 10 anos no Sul do Brasil. Foram utilizados os registros administrativos disponibilizados pelo Ministério do Trabalho e Previdência Social para comparar os indicadores dos empregos formais gerados pelo setor com os outros setores. Os resultados indicaram que o mercado de trabalho ligado à agropecuária tem seguido uma clara tendência de formalização dos vínculos empregatícios. A adoção de tecnologia e mecanização levou a um aumento da produtividade da mão-de-obra, resultando em maior rentabilidade, e fazendo com que o setor passasse a demandar empregos de maior escolaridade e salário médio. Em 2015, conseguiu criar empregos mesmo sob a forte crise econômica que o país atravessou. Sendo assim, verifica-se que a adoção de tecnologia na agropecuária vem aliada a melhora das condições de trabalho, consolidando-o como um dos mais competitivos e sustentáveis do mundo.The agriculture sector is a significant part of Brazilian GDP and exports. The productivity of agricultural products in Brazil has increased through the intense adoption of mechanization and technology processes. In addition, this production system has made the country one of the most competitive in the international scenario, however, it has also caused changes in labor relations. The aim of this study is to analyze the evolution of formal employment in the sector over the last 10 years, with a focus on the southern region of Brazil. Administrative records provided by the Ministério do Trabalho e Previdência Social (Ministry of Employment and Social Security) were used to compare indicators of formal employments generated by the agricultural sector to employments generated by other sectors of the economy. The results revealed a tendency to formalize employment contracts in the sector. Education and salary levels, along with worker productivity, have increased on average in recent years. In addition, the rise of agricultural industry profitability and the devaluation of the Brazilian Real have generated new jobs in the sector. The adoption of technology in agriculture, combined with the improvement of working conditions, consolidated the Brazilian agriculture as one of the most competitive and sustainable in the world

    Effects of calcium supply on soybean plants

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    This paper aims to evaluate the effects that calcium application on leaves and flowers of soybean plants exerts on yield and yield components. Two experiments were carried out in the 2013/2014 crop season under field conditions. In the first experiment, two soybean cultivars – one of determinate growth habit (BMX Ativa) and another of indeterminate growth habit (BMX Alvo) – were submitted to calcium spraying with four nozzles (twin flat, twin flat fan, cone and hollow cone). In the second experiment, soybean plants (BMX Ativa cultivar) were sprayed with calcium on the leaves and flowers at R1 or R3 growth stages. Subsequently, the plants were maintained or not under a 50-percent shade protection during flowering stage. Calcium spraying on soybean leaves or flowers during the flowering stage did not increase pod set, number of seeds, or grain yield. The calcium content in soybean flowers is not affected by foliar application thereof.This paper aims to evaluate the effects that calcium application on leaves and flowers of soybean plants exerts on yield and yield components. Two experiments were carried out in the 2013/2014 crop season under field conditions. In the first experiment, two soybean cultivars – one of determinate growth habit (BMX Ativa) and another of indeterminate growth habit (BMX Alvo) – were submitted to calcium spraying with four nozzles (twin flat, twin flat fan, cone and hollow cone). In the second experiment, soybean plants (BMX Ativa cultivar) were sprayed with calcium on the leaves and flowers at R1 or R3 growth stages. Subsequently, the plants were maintained or not under a 50-percent shade protection during flowering stage. Calcium spraying on soybean leaves or flowers during the flowering stage did not increase pod set, number of seeds, or grain yield. The calcium content in soybean flowers is not affected by foliar application thereof

    Heuristic for solving capacitor allocation problems in electric energy radial distribution networks

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    The goal of the capacitor allocation problem in radial distribution networks is to minimize technical losses with consequential positive impacts on economic and environmental areas. The main objective is to define the size and location of the capacitors while considering load variations in a given horizon. The mathematical formulation for this planning problem is given by an integer nonlinear mathematical programming model that demands great computational effort to be solved. With the goal of solving this problem, this paper proposes a methodology that is composed of heuristics and Tabu Search procedures. The methodology presented explores network system characteristics of the network system reactive loads for identifying regions where procedures of local and intensive searches should be performed. A description of the proposed methodology and an analysis of computational results obtained which are based on several test systems including actual systems are presented. The solutions reached are as good as or better than those indicated by well referenced methodologies. The technique proposed is simple in its use and does not require calibrating an excessive amount of parameters, making it an attractive alternative for companies involved in the planning of radial distribution networks

    A Graph Neural Network Approach to Nanosatellite Task Scheduling: Insights into Learning Mixed-Integer Models

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    This study investigates how to schedule nanosatellite tasks more efficiently using Graph Neural Networks (GNN). In the Offline Nanosatellite Task Scheduling (ONTS) problem, the goal is to find the optimal schedule for tasks to be carried out in orbit while taking into account Quality-of-Service (QoS) considerations such as priority, minimum and maximum activation events, execution time-frames, periods, and execution windows, as well as constraints on the satellite's power resources and the complexity of energy harvesting and management. The ONTS problem has been approached using conventional mathematical formulations and precise methods, but their applicability to challenging cases of the problem is limited. This study examines the use of GNNs in this context, which has been effectively applied to many optimization problems, including traveling salesman problems, scheduling problems, and facility placement problems. Here, we fully represent MILP instances of the ONTS problem in bipartite graphs. We apply a feature aggregation and message-passing methodology allied to a ReLU activation function to learn using a classic deep learning model, obtaining an optimal set of parameters. Furthermore, we apply Explainable AI (XAI), another emerging field of research, to determine which features -- nodes, constraints -- had the most significant impact on learning performance, shedding light on the inner workings and decision process of such models. We also explored an early fixing approach by obtaining an accuracy above 80\% both in predicting the feasibility of a solution and the probability of a decision variable value being in the optimal solution. Our results point to GNNs as a potentially effective method for scheduling nanosatellite tasks and shed light on the advantages of explainable machine learning models for challenging combinatorial optimization problems

    Natural regulatory T cells in rheumatic diseases

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    The healthy immune system must keep the delicate balance between the capacity to respond to exogenous antigens and to keep the tolerance to endogenous antigens. In the absence of an adequate response to exogenous agents the individual is subjected to the deleterious effect of the invasion for pathogens. On the other hand, if the immune system responds in an unwary exacerbated way harmful inflammatory consequences may result. Well-established mechanisms of maintaining self-tolerance include clonal deletion and anergy. Despite the functional evidence in favor of the existence of suppressor T cells, for many years immunologists failed to identify the phenotypic characteristics and to confirm the existence of these lymphocytes. The recent demonstration of different phenotypes of cells, now designated regulatory T cells, reintroduced the paradigm of active regulation of auto-reactivity by particular subtypes of lymphocytes. This subject is of great interest in the contemporary literature. It has been shown that excess regulatory function may be associated with increased susceptibility to infectious and neoplastic diseases. On the other hand decreased regulatory function may cause autoimmunity. In fact, several experimental models of diverse autoimmune conditions have been developed by decreasing or abolishing regulatory T cells. Counterpart of this phenomenon has been sought for in several human autoimmune diseases. At this moment it seems that the most important subtype of regulatory cells are the natural regulatory T cells (TREGS), which represent about 5% of peripheral blood CD4 T lymphocytes. These cells are characterized by the constitutive expression of FOXP3, GITR, CTLA-4 and high levels of CD25. The present article reviews the basic knowledge on the TREGS and the several studies describing the status and function of these cells in autoimmune rheumatic diseased.O sistema imune sadio deve manter o balanço entre a capacidade de responder a agentes infecciosos e de sustentar a autotolerância. A ausência de resposta adequada submete o indivíduo aos efeitos deletérios da invasão por patógenos, ao passo que o sistema respondendo de modo exacerbado pode gerar respostas inflamatórias prejudiciais. Acreditava-se que os mecanismos de deleção clonal e anergia fossem os mecanismos essenciais no controle de clones de linfócitos T auto-reativos. Apesar das evidências funcionais a favor da existência de células T supressoras, por muitos anos a imunologia falhou em identificar suas características fenotípicas e confirmar sua existência, motivo pelo qual o tema passou por longo período de descrédito. A recente demonstração de diferentes fenótipos de células, agora chamadas células T regulatórias, reintroduziu o paradigma de que a auto-reatividade é ativamente regulada também por subtipos particulares de linfócitos. Este tema é de grande interesse contemporâneo e a literatura está repleta de estudos descrevendo novos subtipos de células regulatórias, bem como a função, o fenótipo e a freqüência em condições fisiológicas e patológicas. Nesse universo, destaca-se o subtipo mais importante de células com função imunorregulatória, conhecido como células T regulatórias naturais (T REGS). Representando cerca de 5% dos linfócitos T CD4 do sangue periférico, são células caracterizadas pela expressão constitutiva das moléculas FOXP3, GITR, CTLA-4 e altos níveis de CD25. As alterações deletérias nesta população resultam o desencadeamento de doenças auto-imunes em camundongos, muito semelhantes às doenças auto-imunes humanas. A presente revisão aborda os conhecimentos básicos sobre as T REGS e seu estudo em doenças reumáticas de classificação auto-imune, abrindo perspectivas para o entendimento dos mecanismos de regulação periférica e sobre a fisiopatologia dessas enfermidades. Apresenta, ainda, a perspectiva de futuras abordagens terapêuticas fundamentadas na manipulação dessas células.Universidade Federal de São Paulo (UNIFESP)Universidade Católica de GoiásUNIFESP Divisão de Doenças InfecciosasUniversidade de São Paulo Departamento de Alergia e ImunologiaUNIFESPFleury Medicina Diagnóstica Setor de ImunologiaUNIFESP, Divisão de Doenças InfecciosasUNIFESPSciEL

    Seed inoculation with Azospirillum brasilense in corn plants submitted to water limitation

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    The objective of this work was to evaluate the seed inoculation with Azospirilum brasilense in corn plants under limitation of the water supply. Two assays were carried out in greenhouse conditions, using low nitrogen substrate pots. At first one, corn seeds were inoculated or not with A. brasilense and treated or not with a biostimulant (IBA+GA+KT). At the second experiment, two corn genotypes were inoculated or not with A. brasilense. In both assays, plants were submitted to limited condition of water supply at initial vegetative growth. During this period gas exchange parameters were determined at the plants. After stress period, dry matter and nitrogen content were determined in roots and above ground parts of the plants. In addition, substrate nitrogen content was determined. It was observed effects of water restriction supply for gas exchange parameters and dry matter accumulation. Corn seed inoculation with A. brasilense did not affect plant responses to water limitation; neither improves the nitrogen content on substrate or plants.The objective of this work was to evaluate the seed inoculation with Azospirilum brasilense in corn plants under limitation of the water supply. Two assays were carried out in greenhouse conditions, using low nitrogen substrate pots. To the first assay, corn seeds were inoculated or not with A. brasilense and treated or not with a biostimulant (IBA + KT + GA). At the second assay, two corn genotypes were inoculated or not with A. brasilense. In both assays, plants were submitted to limited condition of water supply at initial vegetative growth. During this period, gas exchange parameters were determined at the plants. After stress period, dry matter and nitrogen content were determined in roots and above ground parts of the plants. In addition, substrate nitrogen content was determined. It was observed effects of water restriction supply for gas exchange parameters and dry matter accumulation. Corn seed inoculation with A. brasilense did not affect plant responses to water limitation; neither improves the nitrogen content on substrate or plants

    Consumo de água e eficiência produtiva de plantas de trigo tratadas com Etil-trinexapac

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    Efficient use of the resources of the growing environment, which is affected by plant traits, is very important for crop adaptation on production system. This work aimed to study the water consumption and yield efficiency of wheat plants treated with Trinexapac-ethyl. Two experiments were carried out, in greenhouse conditions, between 2014 and 2015. Experiments were arranged in randomized blocks design in a factorial 2x3, with four replicates. Two wheat cultivars were sprayed with three Trinexapac-ethyl doses (0, 125 and 188 g a.i. ha-1), at main culm elongation stage. The water consumption, plant height, source-sink distance and the morphological parameters of the flag leaf were evaluated. At the end of the growing cycle, yield and yield components were determined, as well as harvest index. Trinexapac-ethyl reduced plant growth, without affecting grain production. Plant growth regulator application does not reduce either water consumption or wheat crop harvest index.O uso eficiente de recursos do ambiente de cultivo, o qual é influenciado por características da planta, é de grande importância para a adaptação de culturas em sistemas de produção. O presente trabalho teve como objetivo estudar o consumo de água e a eficiência produtiva de plantas de trigo tratadas com Etil-trinexapac. Foram conduzidos dois experimentos, em cultivo protegido, entre 2014 e 2015. Utilizou-se o delineamento experimental de blocos casualizados, em esquema fatorial 2x3, com quatro repetições. Dois cultivares de trigo, foram submetidos à aplicação de três doses de Etil-trinexapac (0, 125 e 188 g ha-1 de i.a.) na fase de alongamento do colmo principal. Foram avaliados: consumo de água, altura da planta e distância fonte e dreno, e os parâmetros morfológicos da folha bandeira. Ao final do ciclo da cultura, foram avaliados componentes de produção, produção de grãos e índice de colheita da cultura. A aplicação de Etil-trinexapac reduziu o crescimento de plantas de trigo, sem afetar a produção de grãos. A aplicação do regulador não reduz o consumo de água, tampouco o índice de colheita da cultura do trigo

    A Feasibility Study Of Fricke Dosimetry As An Absorbed Dose To Water Standard For 192ir Hdr Sources.

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    High dose rate brachytherapy (HDR) using 192Ir sources is well accepted as an important treatment option and thus requires an accurate dosimetry standard. However, a dosimetry standard for the direct measurement of the absolute dose to water for this particular source type is currently not available. An improved standard for the absorbed dose to water based on Fricke dosimetry of HDR 192Ir brachytherapy sources is presented in this study. The main goal of this paper is to demonstrate the potential usefulness of the Fricke dosimetry technique for the standardization of the quantity absorbed dose to water for 192Ir sources. A molded, double-walled, spherical vessel for water containing the Fricke solution was constructed based on the Fricke system. The authors measured the absorbed dose to water and compared it with the doses calculated using the AAPM TG-43 report. The overall combined uncertainty associated with the measurements using Fricke dosimetry was 1.4% for k = 1, which is better than the uncertainties reported in previous studies. These results are promising; hence, the use of Fricke dosimetry to measure the absorbed dose to water as a standard for HDR 192Ir may be possible in the future.9e11515
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