15,836 research outputs found

    Metallic Continuum Quantum Ferromagnets at Finite Temperature

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    We study via renormalization group (RG) and large N methods the problem of continuum SU(N) quantum Heisenberg ferromagnets (QHF) coupled to gapless electrons. We establish the phase diagram of the dissipative problem and investigate the changes in the Curie temperature, magnetization, and magnetic correlation length due to dissipation and both thermal and quantum fluctuations. We show that the interplay between the topological term (Berry's phase) and dissipation leads to non-trivial effects for the finite temperature critical behavior.Comment: Corrected typos, new discussion of T=0 results, to appear in Europhys. Let

    Relationship between bullying behaviours and sleep quality in school-aged children

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    Do children who practice bullying have more sleep disturbances than those who do not practice bullying? The research questions for this study were 1)Are there are differences in sleep quality between aggressors and non-aggressors and between victims and non-victims? 2)Do aggressors have higher SDI than non-aggressors?3)What are the sleep characteristics in aggressors, non-aggressors, victims and non-victims?The purpose of the study was to analyse whether school-agedchildren who practice bullying have worse sleep quality than those who do not practice it and to identify the characteristics of dysfunctional sleep for aggressors?The research method was a cross-sectional study focusing on quantitative methodology. We analysed and compared the results of two questionnaires: bullying, aggressiveness among children with n= 1109, answered by the children and the Children’s Sleep Habits Questionnaire (CSHQ), with n= 883, answered by the parents. A convenience sample of 8 state and private schools in Portugal was worked upon.The SDI of aggressorsis not significantly different from the SDI of non-aggressors. In the 33 CSHQ items, in seven the aggressors manifest significant differences: they go to bed at the same time less often, "fight" going to bed, sleep poorly, wet the bed more often, have a more agitated sleep, wake up with nightmares and are grumpier.There are no differences between the two groups, as both have high SDI. In the aggressors, the SDI is accentuated in relation to non-aggressors with regard to the following: more difficulty in going to bed at the same time, fight more at bedtime, sleep less, wet the bed, have more agitated sleep, wake up with nightmares more and wake up grumpy.info:eu-repo/semantics/publishedVersio

    Uso do germoplasma da Embrapa nos programas de melhoramento de trigo no Brasil.

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    O programa de melhoramento genético de trigo da Embrapa tem papel importante na história da triticultura brasileira, tendo dado origem a mais de 100 novas cultivares para as diferentes regiões do Brasil, ao longo dos quase 40 anos de existência. Entretanto, não se pode atribuir sua importância somente ao número de cultivares criadas, mas também ao impacto de seu germoplasma nos programas de melhoramento genético de outras instituições. O trabalho teve como objetivo quantificar a importância do germoplasma da Embrapa nos programas de melhoramento genético de trigo no Brasil. Foram analisadas as genealogias de todas as cultivares de trigo indicadas para cultivo no País, no período de 2005 a 2012, por obtentor vegetal. No período estudado, a média de participação do germoplasma da Embrapa nas cultivares de outros obtentores é de 58,7%, com destaque para a Biotrigo Genética, a CCGL TEC e OR Melhoramento de Sementes Ltda, respectivamente, com média de uso de 100,0%, 97,5% e 87,7%. The wheat breeding program of Embrapa has an important role in the history of this cereal in Brazil, releasing more than one hundred new cultivars to different regions of the country in almost forty years of existence. However, is not possible assign its importance only to the number of cultivars, but also the impact of their germplasm in other brazilian wheat breeding programs. The objective of this study was to quantify the importance of Embrapa's germplasm in the brazilian wheat breeding programs. Were analyzed the genealogies of all wheat cultivars indicated for growth since 2005 and 2012, by institution. During the study period, the average participation of Embrapa's germplasm on cultivars of other institutions was 58.7%, with emphasis to Biotrigo Genética, CCGL TEC and OR Melhoramento de Sementes Ltda, respectively, in which use was 100%, 97.5% and 87.7%

    Espécies de tripidae associadas ao pinhão-manso.

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    Objetivou-se com esse trabalho, identificar espécies de tripes associadas ao pinhão-manso (Jatropha curcas L). Inspeções periódicas foram realizadas em Unidades Demonstrativas dessa cultura na Embrapa Meio-Norte para coleta e identificação de insetos. Dentre os insetos coletados foram identificadas três espécies de tripes: Retithrips syriacus (Mayet), Heliothrips haemorrhoidalis (Bouché) e Frankliniella schultzei (Trybom), sendo este o primeiro registro destas espécies no estado do Piauí e, em J. curcas, no Brasil

    Growth and yield performance of 'Cabernet Sauvignon' submitted to variations of concentration and application techniques of hydrogen cyanamide in the tropical region of Brazil

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    Wine grape cultivars (Vitis vinifera L.) used in the tropics require special management techniques to regulate the production and to obtain grapes with adequate quality level. The use of chemicals to help in overcoming dormancy and to promote uniform budburst is a wide-spread practice in warm climates regions. In temperate countries grow fruit crops require exposure to chilling to overcome the dormant period of the buds (Erez et al., 2008), that does not happen in tropical conditions. The aim of this work was to evaluate the effects of the application, painted or sprayed, and the concentration of hydrogen cyanamide on the vegetative and yield performances of Cabernet Sauvignon grapevines in the conditions of soil and climate of the San Francisco Valley, Brazil. The experiment was carried out in Lagoa Grande county, Pernambuco, Brazil (9º2?S, 40º11?W), during the 2007 harvest season, when 10, 5 and 2% of hydrogen cyanamide were applied by foam paint roller or by sprayer (this system involved an employee wearing backpack sprayer (model JACTOPJH20) with wands 50 cm in length using a type JA2 nozzle), compared with a control modality (without application)

    Influência de lâminas de irrigação na concentração da maturação de frutos de tomateiro.

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    O objetivo deste trabalho foi avaliar a influência de lâminas de irrigação sob o tamanho de frutos, na cultura do tomateiro para processamento industrial no municipio de Morrinhos-GO.Trabalho 26
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