274 research outputs found

    Scanning Electron Microscopy of the Pericarp and Testa of Several Sorghum Varieties

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    Pericarp thickness (determined by Z gene) varies greatly among sorghum varieties ranging· from very thin (8 ~ m) to very thick (160 ~m ) . Pericarp thickness also varies within an individuual kernel. The areas below the style and near the hilum are the thickest with the sides of the kernel being thinnest . Scanning electron microscopy was used to document differences in pericarp thickness and to explain milling differences . Varieties with a thick pericarp had starch granules in the mesocarp cell layers. Sorghums with a thin pericarp did not have starch granules in the mesocarp except near the hilum and stylar area. U.S. sorghum varieties studied had a testa thickness of 16-40 ~m (side of the kernel) but recently four Malian sorghums from a recent collection had very thin testae of 8-16 ~ m. The Sudanese sorghum Shawaya had a testa ranging in thickness from 28-40~m

    Characterisation of slip and twin activity using digital image correlation and crystal plasticity finite element simulation:Application to orthorhombic αα-uranium

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    Calibrating and verifying crystal plasticity material models is a significant challenge, particularly for materials with a number of potential slip and twin systems. Here we use digital image correlation on coarse-grained α\alpha-uranium during tensile testing in conjunction with crystal plasticity finite element simulations. This approach allows us to determine the critical resolved shear stress, and hardening rate of the different slip and twin systems. The constitutive model is based on dislocation densities as state variables and the simulated geometry is constructed from electron backscatter diffraction images that provide shape, size and orientation of the grains, allowing a direct comparison between virtual and real experiments. An optimisation algorithm is used to find the model parameters that reproduce the evolution of the average strain in each grain as the load is increased. A tensile bar, containing four grains aligned with the load direction, is used to calibrate the model with eight unknown parameters. The approach is then independently validated by simulating the strain distribution in a second tensile bar. Different mechanisms for the hardening of the twin systems are evaluated. The latent hardening of the most active twin system turns out to be determined by coplanar twins and slip. The hardening rate of the most active slip system is lower than in fine-grained α\alpha-uranium. The method developed in the present research can be applied to identify the critical resolved shear stress and hardening parameters of other coarse-grained materials

    Resources and users in the tagging process: approaches and case studies

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    In this contribution we propose a comparison between two distinct approaches to the annotation of digital resources. The former, top-down, is rooted in the cathedral model and is based on an authoritative, centralized definition of the adopted mark-up language; the latter, bottom-up, refers to the bazaar model and is based on the contributions of a community of users. These two approaches are analyzed taking into account both their descriptive potential and the constraints they impose on the reasoning process of recommender systems, with special reference to user profiling. Three case studies are described, with reference to research projects that apply these approaches in the contexts of e-learning and knowledge management

    Educational games as a motivational tool: Considerations on their potential and limitations

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    There is considerable interest in leveraging video games to support students’ motivation. This involves employment of educational (serious) and entertainment games. However, while evidence indicates that games can enhance learning outcomes, doubts persist about whether they retain their enjoyable character in formal learning contexts. This study was carried out within the H2020 Gaming Horizons project, which involved a review of academic literature on the role of games in society, as well as 73 semi-structured interviews with relevant stakeholders, including players and educators, investigating their positions on game-related issues. The interviews suggested that players tend to view game-based learning – and specifically serious games at school – with scepticism. This is partly attributable to the perception that serious games have lower production values than entertainment games, and that gaming, as a voluntary, self-driven activity, clashes with the structured nature of school. Some educators reported individual and gender differences in the motivating power of games. However, the use of entertainment games to foster learning outcomes was seen favourably. Two focus groups devoted to the issue highlighted the need for carefully tailoring the gaming experience to both context and student, and the importance of developing a sustainable business model for enhancing serious games quality

    Library not found: The disconnect between gaming research and development

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    Video games clearly have great educational potential, both for formal and informal learning, and this avenue is being thoroughly investigated in the psychology and education literature. However, there appears to be a disconnect between social science academic research and the game development sector, in that research and development practices rarely inform each other. This paper presents a two-part analysis of this communicative disconnect based on investigations carried out within the H2020 Gaming Horizons project. The first part regards a literature review that identified the main topics of focus in the social sciences literature on games, as well as the chief recommendations authors express. The second part examines 73 interviews with 30 developers, 14 researchers, 13 players, 12 educators, and 4 policy makers, investigating how they perceived games and gaming. The study highlights several factors contributing to the disconnect: different priorities and dissemination practices; the lag between innovation in the games market and research advancements; low accessibility of academic research; and disproportionate academic focus on serious games compared to entertainment games. The authors suggest closer contact between researchers and developers might be sought by diversifying academic dissemination channels, promoting conferences involving both groups, and developing research partnerships with entertainment game companies

    Zoneamento agroecológico do Município de Anastácio - MS.

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    A Embrapa Solos, em parceria com a Secretaria de Estado de Desenvolvimento Agrário, da Produção, da Indústria, do Comércio e do Turismo - SEPROTUR, realizou o Zoneamento Agroecológico do Estado do Mato Grosso do Sul - Fase II - com objetivo de contribuir na indicação de áreas passíveis de exploração agrícola sustentável. No desenvolvimento desse trabalho foram considerados aspectos legais, restrições ambientais, potencial das culturas, aspectos do clima, de geomorfologia e dos solos, todos integrados em ambiente de sistema de informação geográfica com apoio de algebra de mapas, no intuito de avaliar a adequabilidade de uso das terras e apresentar uma proposição de planejamento de uso e ocupação das terras. Os resultados foram consolidados por município e dão origem a esse boletim de pesquisa. No município de Anastácio, as terras indicadas para o uso com lavouras somam 1.425 km², o que equivale a aproximadamente 50% da área total do município, enquanto que as recomendadas para pastagem equivalem a 26,5% e as áreas recomendadas para pastagem especial ou cultivo de arroz correspondem a cerca de 20% da área do município que corresponde a algo como 578 km². Nestas unidades é fundamental avaliar criteriosamente a utilização de pastagens nestas terras quando essas ainda se encontram sob cobertura vegetal, visto que, praticamente 20% destas terras ainda permanecem com vegetação natural em seus diversos graus de conservação. As terras recomendadas para conservação dos recursos naturais equivalem a menos de 80 km², as quais constituem áreas de alta fragilidade ambiental e/ ou apresentam restrições legais de uso como áreas de preservação permanente. As áreas identificadas como zonas recomendadas para recuperação ambiental equivalem a 80 km² e constituem áreas de moderada a alta fragilidade ambiental e/ou que apresentam restrições legais de uso e que já foram desmatadas para o uso com pastagens/agricultura. A área do município de Anastácio apresenta alto grau de ação antrópica das terras, onde mais de 75% das terras sendo utilizadas com pastagens e/ou com agricultura, enquanto que apenas 25% ainda apresentam certo grau de preservação.bitstream/item/141618/1/BPD-202-Zon-Anastacio.pd

    An evaluation of the integration of non-traditional learning tools into a community based breast and cervical cancer education program: The witness project of Buffalo

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    BACKGROUND: Breast and cervical cancer continue to represent major health challenges for African American women. among Caucasian women. The underlying reasons for this disparity are multifactorial and include lack of education and awareness of screening and early detection. Traditional educational methods have enjoyed varied success in the African American community and spawned development of novel educational approaches. Community based education programs employing a variety of educational models have been introduced. Successful programs must train and provide lay community members with the tools necessary to deliver strong educational programs. METHODS: The Witness Project is a theory-based, breast and cervical cancer educational program, delivered by African American women, that stresses the importance of early detection and screening to improve survival and teaches women how to perform breast self examination. Implementing this program in the Buffalo Witness Project of Buffalo required several modifications in the curriculum, integration of non-traditional learning tools and focused training in clinical study participation. The educational approaches utilized included repetition, modeling, building comprehension, reinforcement, hands on learning, a social story on breast health for African American women, and role play conversations about breast and cervical health and support. RESULTS: Incorporating non-traditional educational approaches into the Witness Project training resulted in a 79% improvement in the number of women who mastered the didactic information. A seventy-two percent study participation rate was achieved by educating the community organizations that hosted Witness Project programs about the informed consent process and study participation. CONCLUSION: Incorporating non-traditional educational approaches into community outreach programs increases training success as well as community participation
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