Avaliação do método do salicilato para determinação de amônio em extratos de solos minerais.

O método do salicilato para determinação de amônio em extratos de solo e água tem se mostrado uma alternativa prática e eficiente, embora pouco difundida e utilizada em laboratórios de rotina de análise de solo. Este trabalho objetivou avaliar o potencial desse método na determinação de NH4+ em extratos de solos brasileiros, comparativamente ao método padrão de Kjeldhal. Numa primeira fase, foram feitas avaliações dos fatores: luminosidade (luz natural e escuro), temperatura (ambiente, 37 e 70oC) e tempo de reação (20, 40, 60, 120 e 180 min) no desenvolvimento do complexo azul-esmeralda. Num segundo momento, após padronização da marcha analítica, procederam-se a extração do NH4+ em 12 solos brasileiros de diferentes naturezas e a sua determinação pelos métodos supracitados. As avaliações indicaram que a temperatura ambiente e a luminosidade natural não interferiram acentuadamente nas determinações de amônio de curvas- padrão. Porém a temperatura de 37°C reduziu o tempo para desenvolvimento de cor azul-esmeralda deste método para 60 min, permitindo ainda maior estabilidade da absorbância. Embora o método do salicilato modificado tenha permitido boa correlação com o método de Kjeldhal, foi observada uma capacidade diferenciada de recuperação de amônio em função do aumento de sua concentração no extrato, sendo essa interferência maior para o solo com maior teor de argila e matéria orgânica. Recomenda-se mais estudos com o método para que as interferências observadas sejam sanadas.bitstream/CNPS-2010/14866/1/bpd-133-metodo-salicilato.pd

Noncommutative correction to the entropy of BTZ black hole with GUP

We investigate the effect of noncommutativity and quantum corrections to the temperature and entropy of a BTZ black hole based on a Lorentzian distribution with the generalized uncertainty principle (GUP). To determine the Hawking radiation in the tunneling formalism we apply the Hamilton-Jacobi method by using the Wentzel-Kramers-Brillouin (WKB) approach. In the present study we have obtained logarithmic corrections to entropy due to the effect of noncommutativity and GUP. We also address the issue concerning stability of the non-commutative BTZ black hole by investigating its modified specific heat capacity.Comment: 12 pages, 2 figures; published version in AHE

Embryogenic responses of Vitis spp.: Effects of genotype and polyvinylpyrrolidone

Somatic embryos were obtained from leaf discs excised from cv. Seyve Villard 5276 (Vitis sp.) and from a Brazilian interspecific hybrid derived from Madalena (Vitis sp.) and Magnolia (V. rotundifolia). Experimental procedures were conducted according to HARST (1995) except that phenylalanine was replaced by polyvinylpyrrolidone which improved the embryogenic response of cultivar SV-5276. Standard somatic embryogenesis was confirmed by histological and ultrastructural analysis which also revealed teratological embryonic development. Secondary embryos were observed and documented by scanning microscop

Electronic Phase Separation Transition as the Origin of the Superconductivity and the Pseudogap Phase of Cuprates

We propose a new phase of matter, an electronic phase separation transition that starts near the upper pseudogap and segregates the holes into high and low density domains. The Cahn-Hilliard approach is used to follow quantitatively this second order transition. The resulting grain boundary potential confines the charge in domains and favors the development of intragrain superconducting amplitudes. The zero resistivity transition arises only when the intergrain Josephson coupling $E_J$ is of the order of the thermal energy and phase locking among the superconducting grains takes place. We show that this approach explains the pseudogap and superconducting phases in a natural way and reproduces some recent scanning tunneling microscopy dataComment: 4 pages and 5 eps fig

Good neighbours: distribution of black-tufted marmoset (Callithrix penicillata) in an urban environment

Context Primates are one of the most charismatic and widely studied vertebrate groups. However, the study of new world primates in green patches within urban areas has been neglected. Such primates have been viewed as a source of human–animal conflict; however, their ecological importance to urban ecosystems and their role in human well being is poorly understood. Aims To increase understanding of both ecological and socioeconomical factors affecting the distribution, density and group sizes of urban marmosets in a large Brazilian city (Belo Horizonte). Methods A map of vegetation cover and land use was produced and employed to investigate the distribution of marmosets. An online questionnaire was extensively publicised, which permitted the public to report the occurrence or not of marmosets near their residences. For sites with low salary levels and low internet availability, face-to-face interviews were conducted. Additionally, field surveys were conducted in 120 green areas identified by spatial analysis as potential areas of occurrence. The human population density, salary levels and green areas were posteriorly correlated with marmoset distribution. Key results Despite the urbanisation and high human population density, green fragments within the city still housed marmoset groups. However, the presence of green areas did not always indicate primate presence. Group presence was significantly related to the size of parks or green areas and negatively related to built-up areas, and human density. Salary levels were related to more forested streets and possibly tolerance. Marmosets were classified as urban utilisers. Conclusions The human–wildlife conflict with marmoset species was relatively low, owing to marmoset avoidance of built-up areas. The interaction of marmoset species and city dwellers was mainly limited to borders of forest fragments and inside city parks, and appeared to be human motivated. Implications This study showed the importance of public involvement in wildlife studies in urban environments; clarifying the interaction between city dwellers and wild species is essential to mitigate negative interactions

Parâmetros genéticos de características estimadas da curva de crescimento de ovinos da raça Santa Inês.

Resumo: Este trabalho foi realizado com os objetivos de estudar o ajuste das funções de Richards, Brody, Gompertz, Von Bertalanffy e Logística sobre a curva de crescimento de ovinos Santa Inês e estimar parâmetros genéticos para características calculadas a partir da função de melhor ajuste. Foram utilizadas apenas informações de fêmeas controladas entre os anos de 1993 e 2004, na Embrapa Tabuleiros Costeiros, e entre 1981 e 2004, na Embrapa Caprinos. Para o ajuste das curvas, as análises foram realizadas separadamente para cada rebanho, utilizando-se o procedimento NLIN do software Statistical Analysis System (SAS), por meio do método de GAUSS. Para determinar a função que melhor ajustava os dados, foram utilizados os critérios de coeficiente de determinação (R2), de quadrado médio residual (QMR) e o erro de predição médio (EM). No rebanho da Embrapa Tabuleiros Costeiros, todas as funções subestimaram os pesos, à exceção da curva de Richards. Diferentemente, todas as funções superestimaram o peso predito para o rebanho da Embrapa Caprinos. A curva de Richards foi a que promoveu melhor ajuste nos dois rebanhos. Os valores do peso adulto e da taxa de maturação estimados pela função de Richards foram de 54,38 kg e 0,00144/dia, respectivamente, para o rebanho da Embrapa Tabuleiros Costeiros, e 42,74 kg e 0,00260/dia, respectivamente, para o da Embrapa Caprinos. A função de Richards foi utilizada para estimar curvas individuais de crescimento dos animais. A partir destas curvas, foram estimadas várias características de interesse econômico. Os parâmetros genéticos e os componentes de (co) variância para estas características foram estimados pelo método da Máxima Verossimilhança Restrita Livre de Derivadas (DFREML), utilizando-se o software MTDFREML. As estimativas de herdabilidades direta e materna variaram, respectivamente, de 0,01 a 0,99 e de 0,00 a 0,13. É possível alterar o padrão da curva de crescimento destes animais por meio de seleção. Genetic parameters for traits estimated from the growth curve of Santa Inês hair sheep. Abstract: The aim of this work was to study the adjustment of Richards, Brody, Gompertz, Von Bertalanffy and Logistic functions on the growth curve of Santa Inês hair sheep and to estimate genetic parameters for the traits obtained from the best fitting function. Information from females of the Embrapa Tabuleiros Costeiros herd recorded between 1993 and 2004 and from the Embrapa Caprinos herd recorded between 1981 and 2004 was used. Functions were fitted for each herd, using NLIN procedure of Statistical Analysis System software (SAS), by GAUSS method. The coefficient of determination (R2), residual mean square (QMR) and mean prediction error (EM) were the criteria used to determine the best fitting function. For the Embrapa Tabuleiros Costeiros herd, all the functions subestimated the weights, except the Richards function. On the other hand, all the functions superestimated the weights of animals from the Embrapa Caprinos herd. The best fitting in the both herds was obtained using the Richards function. The respective values of mature weight and maturation rate estimated by Richards function were 54.38 kg and 0.00144/day for Embrapa Tabuleiros Costeiros herd and 42.74 kg and 0.00260/day for Embrapa Caprinos herd. The Richards function was used to estimate individual growth curves of animals in order to estimate genetic parameters and the (co)variance components for traits of economic importance using the Derivative Free Restricted Maximum Likelihood method (DFREML). The estimates of direct and maternal heritabilities ranged, respectively, from 0.01 to 0.99 and 0.00 to 0.13 suggesting the possibility of changing the growth curve of Santa Ines sheep by selection

Numerical relations and skill level constrain co-adaptive behaviors of agents in sports teams

Similar to other complex systems in nature (e.g., a hunting pack, flocks of birds), sports teams have been modeled as social neurobiological systems in which interpersonal coordination tendencies of agents underpin team swarming behaviors. Swarming is seen as the result of agent co-adaptation to ecological constraints of performance environments by collectively perceiving specific possibilities for action (affordances for self and shared affordances). A major principle of invasion team sports assumed to promote effective performance is to outnumber the opposition (creation of numerical overloads) during different performance phases (attack and defense) in spatial regions adjacent to the ball. Such performance principles are assimilated by system agents through manipulation of numerical relations between teams during training in order to create artificially asymmetrical performance contexts to simulate overloaded and underloaded situations. Here we evaluated effects of different numerical relations differentiated by agent skill level, examining emergent inter-individual, intra- and inter-team coordination. Groups of association football players (national - NLP and regional-level - RLP) participated in small-sided and conditioned games in which numerical relations between system agents were manipulated (5v5, 5v4 and 5v3). Typical grouping tendencies in sports teams (major ranges, stretch indices, distances of team centers to goals and distances between the teams' opposing line-forces in specific team sectors) were recorded by plotting positional coordinates of individual agents through continuous GPS tracking. Results showed that creation of numerical asymmetries during training constrained agents' individual dominant regions, the underloaded teams' compactness and each team's relative position on-field, as well as distances between specific team sectors. We also observed how skill level impacted individual and team coordination tendencies. Data revealed emergence of co-adaptive behaviors between interacting neurobiological social system agents in the context of sport performance. Such observations have broader implications for training design involving manipulations of numerical relations between interacting members of social collectives