Gauge fields in a string-cigar braneworld

In this work we investigate the properties of an Abelian gauge vector field in a thin and in a smoothed string-like braneworld, the so-called string-cigar model. This thick brane scenario satisfies the regularity conditions and it can be regarded as an interior and exterior string-like solution. The source undergoes a geometric Ricci flow which is connected to a variation of the bulk cosmological constant. The Ricci flow changes the width and amplitude of the massless mode at the brane core and recover the usual thin string-like behavior at large distances. By numerical means we obtain the Kaluza-Klein (KK) spectrum for both the thin brane and the string-cigar. It turns out that both models exhibit a mass gap between the massless and the massive modes and between the high and the low mass regimes. The KK modes are smooth near the brane and their amplitude are enhanced by the string-cigar core. The analogue Schr\"odinger potential is also tuned by the geometric flow.Comment: The discussion about the Kaluza-Klein spectrum of the gauge field was improved. Numerical analysis was adapted to the conventional notation on Kaluza-Klein number. Some graphics were modified for considering other notation. Results unchanged. References added. Corrected typos. 17 pages. 6 figures. To match version to appears in Physics Letters

Estimativas de parâmetros genéticos clássicos para proteínas totais em feijão-caupi.

Neste trabalho foram estimados parâmetros genéticos para subsidiar trabalhos de melhoramento do feijão-caupi para maior teor de proteínas total. Linhagens F6 e gerações dos cruzamentos IT97K-1042-3 x Canapu e IT97K-1042-3 x BRS Tapaihum foram quantificadas para o teor de proteína total pelo método microKjeldhal. As linhagens F6 foram avaliadas em condições de sequeiro, em blocos ao acaso com duas repetições, enquanto as gerações foram avaliadas em ambiente irrigado, sem delineamento experimental. Todas as variáveis analisadas nas linhagens F6 apresentaram significância, com coeficientes de variação de 2,9% a 50,7%. Os valores da variância de dominância foram considerados como zero, por causa das estimativas negativas obtidas. Os valores da herdabilidade no sentido restrito foram 84,32% e de 45,21% nos cruzamento IT97K-1042-3 X Canapu e IT97K-1042-3 X BRS Tapaihum, respectivamente. Toda a variância genética observada nos dois cruzamentos decorreu dos efeitos aditivos dos genes. As estimativas do número de genes foram em torno de 5,0 e 6,0 para os cruzamentos IT97K-1042-3 X Canapu e IT97K-1042-3 X BRS Tapaihum, respectivamente. Esses resultados indicam que o caráter proteína total bruta é controlado por um número reduzido de genes em feijão-caupi, podendo o acúmulo de alelos favoráveis ser obtido em poucas gerações de seleções

Avaliação e seleção de bulbos de cebola de baixo teor de ácido pirúvico de cultivares adaptadas ao Nordeste.

Diferente de outros países, o Brasil não desenvolveu populações de cebola com baixa pungência, o que poderia aumentar o consumo nacional e criar novas oportunidades para os agricultores. O objetivo deste trabalho foi avaliar o teor de ácido pirúvico em algumas populações de cebola desenvolvidas para o Nordeste brasileiro para orientar trabalhos de melhoramento da espécie. Foram avaliados bulbos de cinco variedades de cebola cultivados nos Campos Experimentais de Bebedouro e Mandacaru/Embrapa Semiárido, em 2010. As condições de cultivo e manejo de fertilizantes foram semelhantes nos dois locais. Os bulbos foram quantificados para o teor de ácido pirúvico por espectrofotometria, sendo selecionados aqueles com teor menor que 5 μmol/mL. Dos 206 bulbos de Bebedouro, os teores de ácido pirúvico variaram de 3,02 μmol/mL a 14,22 μmol/mL de suco de cebola, dos quais selecionou-se 14 (6,8%). Dos 360 bulbos, colhidos no Campo Experimental de Mandacaru, os teores de ácido pirúvico variaram de 3,65 μmol/mL a 18,52 μmol/mL de suco de cebola; destes 13 (3,6%) foram selecionados. Obteve-se sementes em 18 plantas dos 27 bulbos selecionados, o que possibilitará um novo ciclo de seleção recorrente, visando o desenvolvimento de populações de cebola com baixos teores de ácido pirúvico para o Nordeste brasileiro

Coleman meets Schwinger

It is well known that spherical D-branes are nucleated in the presence of an external RR electric field. Using the description of D-branes as solitons of the tachyon field on non-BPS D-branes, we show that the brane nucleation process can be seen as the decay of the tachyon false vacuum. This process can describe the decay of flux-branes in string theory or the decay of quintessence potentials arising in flux compactifications.Comment: 5 pages, 2 figure

Recognizing opportunities across campus: the effects of cognitive training and entrepreneurial passion on the business opportunity prototype

We analyze the effects of the program Cognitive Entrepreneurial Training in Opportunity Recognition on the accurate assessment of prototypical viability of business opportunities. The training integrates the principles of experiential learning and is designed to reach students across campus. We also investigate the moderating role of entrepreneurial passion on opportunity recognition learning. We use a quasi-experimental design with pre-test, post-test in two European universities. The results demonstrate that the training has positive significant effects on the accurate identification of business opportunities' prototypical viability. Intense positive feelings about entrepreneurship moderate the learning process. We provide insights into entrepreneurship education practice across campus.info:eu-repo/semantics/publishedVersio

Os desafios e as perspectivas da extensão pesqueira: um diagnóstico preliminar da pesca artesanal no Estado do Tocantins.

Este estudo buscou analisar esta questão a partir do caso do serviço de extensão rural pesqueira no estado do Tocantins, examinando as características do trabalho desenvolvido pelas organizações que prestam serviços de ATER aos pescadores artesanais naquela unidade da federação

Global priorities for conservation across multiple dimensions of mammalian diversity

Conservation priorities that are based on species distribution, endemism, and vulnerability may underrepresent biologically unique species as well as their functional roles and evolutionary histories. To ensure that priorities are biologically comprehensive, multiple dimensions of diversity must be considered. Further, understanding how the different dimensions relate to one another spatially is important for conservation prioritization, but the relationship remains poorly understood. Here, we use spatial conservation planning to (i) identify and compare priority regions for global mammal conservation across three key dimensions of biodiversity-taxonomic, phylogenetic, and traits-and (ii) determine the overlap of these regions with the locations of threatened species and existing protected areas. We show that priority areas for mammal conservation exhibit low overlap across the three dimensions, highlighting the need for an integrative approach for biodiversity conservation. Additionally, currently protected areas poorly represent the three dimensions of mammalian biodiversity. We identify areas of high conservation priority among and across the dimensions that should receive special attention for expanding the global protected area network. These high-priority areas, combined with areas of high priority for other taxonomic groups and with social, economic, and political considerations, provide a biological foundation for future conservation planning efforts

What are the Best Hierarchical Descriptors for Complex Networks?

This work reviews several hierarchical measurements of the topology of complex networks and then applies feature selection concepts and methods in order to quantify the relative importance of each measurement with respect to the discrimination between four representative theoretical network models, namely Erd\"{o}s-R\'enyi, Barab\'asi-Albert, Watts-Strogatz as well as a geographical type of network. The obtained results confirmed that the four models can be well-separated by using a combination of measurements. In addition, the relative contribution of each considered feature for the overall discrimination of the models was quantified in terms of the respective weights in the canonical projection into two dimensions, with the traditional clustering coefficient, hierarchical clustering coefficient and neighborhood clustering coefficient resulting particularly effective. Interestingly, the average shortest path length and hierarchical node degrees contributed little for the separation of the four network models.Comment: 9 pages, 4 figure