984 research outputs found

    The Demographic Transition and the Sexual Division of Labor

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    This paper presents a theory where increases in female labor force participation and reductions in the gender wage-gap are generated as part of a single process of demographic transition, characterized by reductions in mortality and fertility. The paper suggests a link between changes in mortality and transformations in the role of women in society that has not been identified before in the literature. Mortality reductions affect the incentives of individuals to invest in human capital and to have children. Particularly, gains in adult longevity reduce fertility, increase investments in market human capital, increase female labor force participation, and reduce the wage differential between men and women. Child mortality reductions, though reducing fertility, do not generate this same pattern of changes. The model reconciles the increase in female labor market participation with the timing of age-specific mortality reductions observed during the demographic transition. It generates changes in fertility, labor market attachment, and the gender wage-gap as part of a single process of social transformation, triggered by reductions in mortality.

    Toward in vitro fertilization in Brachiaria spp.

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    Brachiaria are forage grasses widely cultivated in tropical areas. In vitro pollination was applied to accessions of Brachiaria spp. by placing pollen of non-dehiscent anthers on a solid medium near isolated ovaries. Viability and in vitro germination were tested in order to establish good conditions for pollen development. Comparing sexual to apomictic plants, apomictic pollen has more abortion after meiosis during the microspore stage and a lower viability and, of both types, only some plants have sufficient germination in a high sugar concentration. Using in vitro pollination with the sexual plant, the pollen tube penetrates into the nucellus and micropyle, but the embryo sac degenerates and collapses. In the apomictic B. decumbens, in vitro pollination leads to the transfer of the sperm nuclei into the egg cell and the central cell. The results are discussed according to normal fertilization and barriers in sexual and apomictic plants

    Estudos estruturais das enzimas envolvidas com o mecanismo de produção de ácidos orgânicos da bactéria G. Diazotrophicus utilizando métodos computacionais.

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    Ga5DH é uma enzima que exerce um papel fundamental na regulação do fluxo das fontes de carbono e energia nas bactérias, e na produção de Ácidos Orgânicos, entre eles o 5-Ceto-D-Gluconato (5KGA) [1,2]. Devido à importância deste ácido na indústria química [3], há um grande interesse em sua estrutura. Isto nos leva a apresentar a estrutura teórica de Ga5DH de Gluconacetobacter diazotrophicus, obtida com Modelagem por Homologia. Dez modelos foram gerados no programa MODELLER [4], baseados na estrutura de Gluconate 5- dehydrogenase de Streptococcus suis (PDB 3cxr), a única proteína Ga5DH resolvida experimentalmente até então.Trabalho apresentado na V Mostra de Trabalhos de Estagiários e Bolsistas, Campinas, out. 2009

    EVALUATION OF THE EFFECTS OF ILLUMINATION, TEMPERATURE AND PAINTING FINISH IN PSP TECHNIQUE

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    This paper reports the results of global pressure measurements on a NACA0012 profile, obtained with the Pressure Sensitive Paint technique (PSP), and compares them with conventional pressure tap measurements with the purpose of analyzing the influence of parameters as illumination efficiency and temperature variation of the air flow in the accuracy of the PSP experimental results. The experimental measurements were conducted in the Pilot Transonic Wind Tunnel (TTP) of the Instituto de Aeronáutica e Espaço (IAE) for Mach number values of 0.4, 0.6 and 0.8. The experiments showed that in a carefully prepared experiment, under appropriated operational conditions, and rigorous adjustments of the PSP components, the obtained results can be accurate. Moreover, even when the influence of temperature is significant and the illumination condition is not ideal, it was possible to estimate well the impact caused in the pressure distribution over the model surface

    Medição de qualidade de sementes de canola com visão computacional e aprendizado de máquina.

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    Produtos originados dos grãos da canola, como óleo, farinha e biodiesel, são diretamente afetados pela qualidade desses grãos. O uso da tecnologia tem contribuído para a identificação dos grãos impuros ou em estágios diferentes de maturidade. A visão computacional em conjunto com o aprendizado de máquina pode gerar ferramentas capazes de avaliar a qualidade das sementes de forma não invasiva, sem destruir amostras e com baixo custo, uma vez que utiliza imagens digitais como insumo. O presente estudo propõe o uso de visão computacional e aprendizado não supervisionado de máquina para análise de sementes de canola a partir de imagens digitais, com o objetivo de contar, identificar cada semente e calcular o percentual de grãos maduros. Os resultados mostraram que o método K?Means pode ser usado para contar e identificar sementes de canola em fotografias com alta precisão. Na amostra, foram identificadas noventa e três sementes maduras, quatro verdes e três secas

    Emerging biotechnologies: bioinformatics services applied to agriculture.

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    Abstract - Bioinformatics is an emergent biotechnological field of study marked by interdisciplinarity and complexity. It involves the application and development of computational tools to biological data in order to process, generate, and disseminate biological knowledge. Bioinformatics is characterized by an intense generation of data and information (configured as a context of big data and e-science), associated with the need for computational resources with high processing and storage capacities and highly qualified and interdisciplinary staff, often found only in academia. The objective of this paper is to describe the organizational model and collaborative innovation activities of the Bioinformatics Multi-user Laboratory (LMB, in the acronym in Portuguese). The LMB is a facility located at the Brazilian Agricultural Research Corporation (Embrapa), the main Brazilian agricultural research public institute, formed by 46 Research and Service Centers distributed throughout Brazil and by several laboratories and business offices abroad, in America, Africa, Asia and Europe. Its mission involves to contribute to the advance of the frontier of knowledge in bioinformatics by: incorporating new technologies and enabling efficient solutions to the demands related to this field; providing access to high performance computing infrastructure and developing human skills. Considering the importance of biotechnology in the context of agricultural research, Embrapa implemented the LMB in 2011, with the purpose of increasing the efficiency of the use of computational, human and technological resources of Embrapa by providing access to bioinformatics computational resources, offering research collaboration possibilities and consultation on project design and biological data analysis. A case-study was conducted based on documentary research and interviews. The main findings of this research are: the description of the organizational model of LMB, the management team and roles; theservices it provides; its access policies and procedures of customer service.Altec 2015

    In vitro infectivity of Spodoptera frugiperda multiple nucleopolyhedrovirus to different insect cell lines.

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    <div><p>Abstract: The objective of this work was to evaluate the response of an in vitro host range to Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), a pathogenic virus to the fall armyworm (Spodoptera frugiperda, Lepidoptera: Noctuidae), for the further development of a biopesticide based on cell culture systems. The cell lines from Bombyx mori (BM-5), Lymantria dispar (IPLB-LD-625Y), Trichoplusia ni (BTI-Tn-5B1-4), Anticarsia gemmatalis (UFL-AG-286), and S. frugiperda (IPLB-SF-21AE and Sf9) were tested for their susceptibility to a highly-virulent Brazilian isolate of SfMNPV. The cytopathic effects induced by the virus, the production of viral particles, and the synthesis of viral polypeptides were examined and compared. Both S. frugiperda cell lines showed hypertrophy of cell nuclei and production of many polyhedra. The SDS-Page of radiolabed proteins showed that the cell protein synthesis was shutoff, while an intense band of about 30 kDa, recognized as polyhedrin, was synthesized. The other cell lines did not show polyhedra production, although some of them underwent morphological changes and protein synthesis shutdown in response to virus infection. The SF-21 and Sf9 cell lines are recommended for further in vitro production of SfMNPV.</p></div

    Segmentation-based blood flow parameter refinement in cerebrovascular structures using 4D arterial spin labeling MRA

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    Objective: Cerebrovascular diseases are one of the main global causes of death and disability in the adult population. The preferred imaging modality for the diagnostic routine is digital subtraction angiography, an invasive modality. Time-resolved three-dimensional arterial spin labeling magnetic resonance angiography (4D ASL MRA) is an alternative non-invasive modality, which captures morphological and blood flow data of the cerebrovascular system, with high spatial and temporal resolution. This work proposes advanced medical image processing methods that extract the anatomical and hemodynamic information contained in 4D ASL MRA datasets. Methods: A previously published segmentation method, which uses blood flow data to improve its accuracy, is extended to estimate blood flow parameters by fitting a mathematical model to the measured vascular signal. The estimated values are then refined using regression techniques within the cerebrovascular segmentation. The proposed method was evaluated using fifteen 4D ASL MRA phantoms, with ground-truth morphological and hemodynamic data, fifteen 4D ASL MRA datasets acquired from healthy volunteers, and two 4D ASL MRA datasets from patients with a stenosis. Results: The proposed method reached an average Dice similarity coefficient of 0.957 and 0.938 in the phantom and real dataset segmentation evaluations, respectively. The estimated blood flow parameter values are more similar to the ground-truth values after the refinement step, when using phantoms. A qualitative analysis showed that the refined blood flow estimation is more realistic compared to the raw hemodynamic parameters. Conclusion: The proposed method can provide accurate segmentations and blood flow parameter estimations in the cerebrovascular system using 4D ASL MRA datasets. Significance: The information obtained with the proposed method can help clinicians and researchers to study the cerebrovascular system non-invasively
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