Teleparallel Spin Connection

A new expression for the spin connection of teleparallel gravity is proposed, given by minus the contorsion tensor plus a zero connection. The corresponding minimal coupling is covariant under local Lorentz transformation, and equivalent to the minimal coupling prescription of general relativity. With this coupling prescription, therefore, teleparallel gravity turns out to be fully equivalent to general relativity, even in the presence of spinor fields.Comment: 2 pages, RevTeX, to appear in Phys. Rev D (Brief Report

Concentrações de etileno para climatização de plátano 'Terra 1 Maranhão'.

Comercialmente, bananas e plátanos são colhidos na fase conhecida como 'verde-11 maduro' e após a colheita os frutos amadurecem de forma desuniforme. Por isso, o 12 método de desverdecimento chamado de climatização tem sido utilizado para 13 proporcionar o amadurecimento rápido e homogêneo dos frutos. No entanto, existem 14 poucas informações sobre climatização de plátanos na literatura. O objetivo deste 15 trabalho foi avaliar o efeito da climatização com diferentes concentrações de etileno na 16 qualidade física e química de frutos de plátanos 'Terra Maranhão'. Quatro concetrações 17 de etileno foram aplicados: 50, 100 e 500 µL L-1 de etileno e o controle (sem etileno). 18 Os tratamentos foram aplicados por meio de gerador comercial de etileno (Banasil®) e a 19 climatização foi realizada a 25°C por 24 horas. As avaliações foram realizadas logo 20 após os frutos serem retirados da climatização e quando os frutos atingiram o estádio 6, 21 além da avaliação após a colheita (caracterização). As variáveis analisadas foram: massa 22 do fruto, diâmetro do fruto e da polpa, firmeza da polpa, acidez titulável (AT), sólidos 23 solúveis (SS), relação SS/AT e pH. Frutos de plátanos tratados com 50 e 500 µL L-1 de 24 etileno apresentaram casca completamente amarela (estádio 6) no terceiro dia após a 25 climatização e amadureceram em menor tempo, em comparação às frutas dos demais 26 tratamentos. Embora as aplicações de 50 e 500 µL L-1 de etileno tenha antecipado o 27 amadurecimento dos frutos, a concentração de 100 µL L-1 de etileno foi a que 28 proporcionou frutos de melhor qualidade física e química

Systemic release of volatiles by Brassica oleracea var. acephala induced by Pieris brassicae predation.

Pieris brassicae is a specialist on crucifers and its interactions with some of its host plants have been increasingly studied given their importance in pest management, chemical ecology and entomology. Plants are known to respond to insect attack by releasing volatiles that can either warn neighbour plants to the presence of a predator or attract insect parasitoids, thus reducing the attack efficiency. The influence of P. brassicae feeding on Brassica oleracea L. var. acephala (kale) was investigated, namely, its effect in the volatiles released by the plant through time. Substantial differences, mainly quantitative, were found between the volatiles composition of B. oleracea var. acephala before the attack and after insect feeding. More than 40 compounds were found, between terpenes (monoterpenes and sesquiterpenes) and lipoxygenase pathway byproducts (alcohols and aldehydes), ketones, norisoprenoids, among others. After insect attack, monoterpenes like limonene, eucalyptol, camphor and caryophyllene increased noticeably. These compounds have been regarded as markers in local tissue responses and in this study an increase in their concentration was detected at 1 and 4 hours after feeding, with subsequent reduction after 8 hours. Menthol, menthone, phenol and sabinene were found only in the time following the attack. A considerable increase in hexenyl acetate, a well known semiochemical, was also found, with this compound being the major peak in all experiments, rising with time. These findings provide further knowledge of the ecological interactions between these two species and, given the chemical diversity of these matrices, they may constitute a good source of health promoting compounds.Fundação para a Ciência e Tecnologia for financial support (PTDC/AGRAAM/ 64150/2006). F. Fernandes (SFRH/BD/37963/2007

Metabolic fate of dietary volatile compounds in Pieris brassicae

In this work, the evolution of the qualitative and quantitative profile of the volatile fraction of Pieris brassicae after feeding on Brassica oleracea var. acephala (kale) was monitored through time. HS-SPME/GC-MS was applied to both the host plant and the living insect and its excrements. A total of seventy seven compounds (lipoxygenase pathway by-products, nitrogen compounds, norisoprenoids, sulphur compounds, terpenes, among others) were identified. Thirty eight compounds were identified in insect after 2 h of starvation and forty eight compounds in excrements. Qualitative and quantitative changes were detected along time. Dimethyldisulfide, dimethyltrisulfide, limonene and eugenol were major compounds for all analysed times in both matrices, being limonene an important compound in insect after starvation. The accumulation by P. brassicae of some compounds, such as limonene, was verified, suggesting a mechanism by which the insect can take benefit from bioactive constituents from the diet. Along with accumulation, complete excretion of some compounds, including nitrogen bearing compounds, by-products of glucosinolates was detected. These results reflect one of the strategies used to overcome plant barriers, namely detoxification of toxic compounds. The findings contribute to the knowledge of the metabolization of the volatile compounds in insects and contribute to the body of knowledge of this ecologic system.FC

Grazing management strategies for massaigrass-forage peanut pastures. 1. Dynamics of sward conditions and botanical composition.

This study was carried out from October 2002 to December 2003 to evaluate the dynamics of sward condition and botanical composition of a mixed massaigrass (Panicum maximum x P. infestum, cv. Massai) and forage peanut (Arachis pintoi Ac 01) pasture, intermittently stocked at three daily herbage allowance levels (9.0, 14.5 and 18.4% live weight). Sward condition was characterized in each grazing cycle in terms of the pre- and post-grazing sward height, forage mass and percentage of bare ground. Botanical composition (grass, legume and weeds) was evaluated before each grazing period. Sward height and forage mass increased linearly with increasing herbage allowance (HA) levels, and higher values were observed during the rainy season. Percentage of bare ground increased primarily at the lowest HA level. Percentage of forage peanut increased throughout the experimental period, primarily in the barest and shortest swards, under the lowest HA level. In the last quarter of 2003 the legume constituted 23.5, 10.6 and 6.4% of the pasture forage mass, respectively, from the lowest to the highest HA level. These results suggest that forage peanut can be successfully associated with massaigrass, as long as the pre-grazing sward height is maintained shorter than 65-70 cm, which will prevent excessive shading to the legume

Grazing management strategies for massaigrass-forage peanut pastures. 2. Productivity, utilization and sward structure.

This study was carried out to evaluate the productivity, utilization and sward structure of a mixed massaigrass (Panicum maximum x P. infestum, cv. Massai) and forage peanut (Arachis pintoi Ac 01) pasture, intermittently stocked at three daily herbage allowance levels (9.0, 14.5 and 18.4% of live weight). In each grazing cycle, dry matter (DM) accumulation rates, defoliation intensity (%), grazing depth (%) and grazed horizon (cm) were evaluated. The structure of massaigrass tussocks was characterized in both dry and rainy seasons by measuring its pre-grazing morphological composition and postgrazing height and density (tussocks/m). Pastures submitted to higher herbage allowance (HA) levels showed higher productivity, but were less efficiently utilized. On average, over the experimental period, DM accumulation rates increased linearly from 56.8 to 81.3 kg/ha/day as HA levels increased from 9.0 to 18.4% of live weight. However, defoliation intensity and grazing depth declined linearly with increasing HA levels. During the dry season, pre-grazing morphological composition of massaigrass was characterized by 41% of green leaf blades, 10% of pseudostems and 49% of dead material, irrespective of HA levels. In the rainy season, however, it showed higher percentage of green leaf blades and lower percentage of pseudostems when submitted to lower HA levels, although there were not differences in relation to percentage of dead material. The structure of massaigrass tussocks tended to deteriorate at high HA levels

Grazing management strategies for massaigrass-forage peanut pastures. 3. Definition of sward targets and carrying capacity.

This study was carried out to define sward management targets for mixed Massaigrass (Panicum maximum x P. infestum, cv. Massai) and forage peanut (Arachis pintoi Ac 01) pastures in the Western Brazilian Amazon. Seasonal variation in the pasture carrying capacity was also analyzed. Pastures were intermittently stocked at three daily herbage allowance levels (9.0, 14.5 and 18.4% of live weight) from October 2002 to December 2003. Sward targets were defined in terms of the sward condition that best conciliated the grass-legume balance, the maintenance of the structure of Massaigrass tussocks and the equilibrium between forage production and utilization. For the Western Brazilian Amazon conditions, the following sward management targets can be recommended for mixed Massaigrass and forage peanut pastures under intermittent stocking: pregrazing height ranging from 50-55 cm (June to September) to 65-70 cm (October to May), and post-grazing height from 30- 35 cm (June to September) to 35-40 cm (October to May). Annual carrying capacity of this mixed pasture in 2003 was 2.7 AU/ha. The average carrying capacity during the dry season (1.8 AU/ha) was 50% lower than that observed during the rainy season (3.6 AU/ha)

Avaliação de genótipos de feijão para recomendação de cultivares no Estado do Rio de Janeiro.

Considerando que o processo de seleção de cultivares é contínuo, buscando selecionar materiais cada vez mais adaptados e que atendam as exigências do mercado, em 2010 a PESAGRO-RIO em parceria com a EMBRAPA-CNPAF, realizou dois testes de adaptação local (TAL) e duas Unidades Demonstrativas em locais representativos do Norte Fluminense.CONAFE

Response of \u3cem\u3eArachis pintoi\u3c/em\u3e to Grazing Intensity When Associated with Different Grasses

Lack of legume persistence is one of the main reasons for poor utilisation of grass-legume pastures in the tropics. Arachis pintoi (forage peanut) is currently the most promising forage legume for the humid tropics, mainly because of good persistence under grazing (Grof, 1985; Fisher & Cruz, 1995). The objective of this work was to show how two accessions of A. pintoi react to increasing herbage allowance levels when associated with two different grasses