280 research outputs found

    The potential of agroforestry to increase primary production in the Sahelian and Sundanian zone of West Africa.

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    Primary production is limited by water availability in the N Sahelian zone only; elsewhere in the region nutrient availablility is critical. Woody species influence the water balance via rainfall interception, the influence on evapotranspiration and the influence on water infiltration. The ultimate result for grasslands and crops depends upon local conditions. Processes that influence nutrient availability under trees are those acting via redistribution, those reducing nutrient losses and those increasing soil fertility. Of the latter processes, serious limitations exist in the region concerned: N-fixation is limited by P shortage mainly and deep rooting is very limited and so is possible uptake of minerals from deep soil layers. The positive influence from woody species on soil fertility and primary production varies with average annual rainfall and soil type. This positive influence is basically linked to the redistribution of nutrients and water, the internal nutrient cycling and the related enlarged plant-litter-soil nutrient cycle

    Composition of fatty acids of the rabbit meat in function of the genetic line and the diet

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    [SPA] El efecto de dos dietas con diferentes niveles de fibra en la composición del perfil de ácidos grasos de la carne de conejo fue estimado para un total de 150 animales de tres líneas genéticas diferentes (Ebro - EB y Grimaud - GR, seleccionados por velocidad de crecimiento e Hyla - HY seleccionada por aptitud maternal). Los animales fueron alimentados con una dieta control (C) (25% de fibra) y otra más energética (HE) (17% de fibra). Tras el sacrificio a las 8 y a las 12 semanas de edad analizamos el contenido nutricional de la carne de una pata trasera, obteniendo el porcentaje de grasa intramuscular y el perfil de ácidos grasos. Observamos que el contenido de grasa intramuscular desciendió conforme avanza la edad, al igual que el ratio omega 6/omega 3 (P< 0,05). La línea de aptitud maternal (HY) presentaron diferencias significativas respecto a EB y GR en el contenido de PUFA a las 12 semanas, siendo mayor su concentración de estos ácidos grasos. Respecto a las dos dietas, hay diferencias en el ácido palmítico (C16:0) a las 12 semanas teniendo un contenido superior los animales alimentados con la dieta HE (28,97 % ± 0,05) que los alimentados con la dieta C (27,75 % ± 0,05). Así, el contenido en ácidos grasos puede ir influenciado por la edad, por la línea genética, y en menor medida por la dieta. [ENG] The effect of two diets with different fiber levels on the composition of the fat profile of the rabbit meat was estimated for a total of 150 animals from three different genetic lines (Ebro - EB and Grimaud - GR, selected by growth rate and Hyla - HY selected by maternal aptitude). The animals were fed a control diet (C) (25% fiber) and another energy (HE) (17% fiber). After slaughter at 8 and 12 weeks of age, the nutritional content of the meat of a hind leg, was analyzed obtaining the percentage of intramuscular fat and the profile of fatty acids. We observed that the intramuscular fat content decreased according to age, as did the omega 6 / omega 3 ratio (P <0.05). The maternal aptitude line (HY) presented significant differences respect to EB and GR in the PUFA content at 12 weeks, with a higher concentration of these fatty acids. With respect to both diets, there is differences in palmitic acid (C16: 0) at 12 weeks with a higher content of animals fed with the HE diet (28.97% ± 0.05) than foods with C diet (27.75% ± 0.05). Thus, the fat content can be influenced by the age, by the genetic line, and to a lesser extent by the diet.La realización del presente trabajo ha sido posible gracias al apoyo económico del proyecto CDTI (IDI-20120024) y al apoyo técnico de la empresa QUIN s.l

    Subgeneric delimitation of the plant genus Phyllanthus (Phyllanthaceae)

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    Over two centuries of taxonomic studies on the species rich genus Phyllanthus have culminated in a broadand complicated classification with many subgenera and (sub)sections. Past taxonomic work has only focused on local revisions, mostly because of the size of the genus. In this study we aim to summarize most of the taxonomic work in a list containing the infrageneric delimitations of Phyllanthus. This work will serve as a reference, placing most currently recognized species in subgenera and if possible, in sections for further study. Here we recognize 880 species of Phyllanthus, classified in 18 subgenera, 70 sections and 14 subsections. A few taxonomic changes are necessary to reconcile published phylogenetic data with the current classification. Subsections Callidisci and Odontadenii are raised to sectional rank, while section Eleutherogynium and section Physoglochidion are reduced to subsections and P. oxycarpus is transferred to the genus Glochidion. A provisional key for the subgeneric classification of Phyllanthus is provided.Naturali

    Composition of fatty acids of the rabbit meat in function of the genetic line and the diet

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    [SPA] El efecto de dos dietas con diferentes niveles de fibra en la composición del perfil de ácidos grasos de la carne de conejo fue estimado para un total de 150 animales de tres líneas genéticas diferentes (Ebro - EB y Grimaud - GR, seleccionados por velocidad de crecimiento e Hyla - HY seleccionada por aptitud maternal) alimentados con una dieta control (C) (25% de fibra) y otra más energética (HE) (17% de fibra). A las 8 y a las 12 semanas de edad analizamos el porcentaje de grasa intramuscular y el perfil de ácidos grasos. El contenido de grasa intramuscular desciende conforme avanza la edad, al igual que desciende el ratio omega 6/omega 3 (P< 0,05). HY presenta diferencias significativas respecto a EB y GR en el contenido de ácidos grasos poliinsaturados a las 12 semanas, siendo mayor su concentración de estos ácidos grasos. El ácido palmítico (C16:0) a las 12 semanas teniendo un contenido superior los animales alimentados con la dieta HE (28,97 % ± 0,05) que los alimentados con la dieta C (27,75 % ± 0,05). Así el contenido en ácidos grasos puede ir influenciado por la edad, por la línea genética, y en menor medida por la dieta. [ENG] The effect of two diets with different fiber levels on the composition of the fat profile of the rabbit meat was estimated for a total of 150 animals from three different genetic lines (Ebro - EB and Grimaud - GR, selection by growth rate and Hyla - HY selected by maternal aptitude). The animals were fed a control diet (C) (25% fiber) and another energy (HE) (17% fiber). After slaughter at 8 and 12 weeks of age, we obtained the percentage of intramuscular fat and the profile of fatty acids. We observed that the intramuscular fat content decreased according to age, as did the omega 6/omega 3 ratio (P <0.05). The maternal aptitude line (HY) presents significant differences respect to EB and GR in the PUFA content at 12 weeks, with a higher concentration of these fatty acids. With respect to both diets, there is differences in palmitic acid (C16: 0) at 12 weeks with a higher content of animals fed with the HE diet (28.97% ± 0.05) than foods with C diet (27.75% ± 0.05). Thus, the fat content can be influenced by the age, by the genetic line, and to a lesser extent by the diet.La realización del presente trabajo ha sido posible gracias al apoyo económico del proyecto CDTI (IDI-20120024) y al apoyo técnico de la empresa QUIN S.L

    Molecular phylogenetics of Phyllanthus sensu lato (Phyllanthaceae): Towards coherent monophyletic taxa

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    The genus Phyllanthus is paraphyletic as currently circumscribed, with the genera Breynia, Glochidion and Synostemon nested within it. A phylogeny based on nuclear (ITS, PHYC) and chloroplast (matK, accD-psaI, trnS-trnG) markers is presented, including 18/18 subgenera and 53/70 sections. Differences in habit, branching type, floral and fruit characters are discussed, and we find indications for shifts in pollination and dispersal strategies possibly underlying the convergent evolution of these characters in multiple clades. Several taxonomic issues were found in the subgeneric classification of Phyllanthus that will require new transfers and rank changes. Phyllanthus subg. Anesonemoides, subg. Conami, subg. Emblica, subg. Gomphidium, subg. Kirganelia and subg. Phyllanthus are polyphyletic, and several sections appear to be paraphyletic (e.g., P. sect. Anisonema, sect. Emblicastrum, sect. Pseudoactephila, sect. Swartziani, and sect. Xylophylla); P. subg. Phyllanthodendron is furthermore paraphyletic with the genus Glochidion nested within. To create a classification of tribe Phyllantheae that comprises exclusively monophyletic taxa, it is necessary to treat several clades at the same taxonomic rank as the genera Breynia, Glochidion and Synostemon. Since combining all genera would lead to one giant heterogeneous genus that is difficult to define, we recommend dividing Phyllanthus into several monophyletic genera, which have previously been recognized and often possess diagnostic (combinations of) morphological characters. This new classification is forthcoming.Plant sciencesNaturali

    A revised phylogenetic classification of tribe Phyllantheae (Phyllanthaceae)

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    The majority of tribe Phyllantheae (Phyllanthaceae) is currently placed in the paraphyletic genus Phyllanthus and discussions have persisted on how to resolve this issue. Here, we split Phyllanthus into ten monophyletic genera, which are all reinstatements of former genera, but with changes made to the circumscription and constituent species of each group. The genera Breynia, Glochidion and Synostemon were recently found to be nested within Phyllanthus and discussions ensued whether or not to subsume everything into Phyllanthus s.l. Instead of combining all these genera, we here implement the solution of splitting Phyllanthus into strictly monophyletic genera to ensure that the classification is consistent with the latest phylogenetic results. The new classification is based on a phylogenetic framework combined with differences in habit, branching type, floral, fruit and pollen morphology. With this new division of the genus Phyllanthus, tribe Phyllantheae will consist of the following 18 genera: Breynia, Cathetus, Cicca, Dendrophyllanthus, Emblica, Flueggea, Glochidion, Heterosavia, Kirganelia, Lingelsheimia, Lysiandra, Margaritaria, Moeroris, Nellica, Nymphanthus, Phyllanthus, Plagiocladus and Synostemon. As a result of the reinstated genera, five new names for illegitimate combinations or previous overlooked nomenclatural anomalies and 645 new combinations are proposed. Several keys are provided to distinguish the reinstated genera. Full species lists are given for the reinstated genera treated here except for Breynia, Synostemon and Glochidion.Plant sciencesNaturali

    Search for the Flavor-Changing Neutral Current Decay D0μ+μD^0 \to \mu^+\mu^- with the HERA-B Detector

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    We report on a search for the flavor-changing neutral current decay D0μ+μD^0 \to \mu^+\mu^- using 50×10650 \times 10^6 events recorded with a dimuon trigger in interactions of 920 GeV protons with nuclei by the HERA-B experiment. We find no evidence for such decays and set a 90% confidence level upper limit on the branching fraction Br(D0μ+μ)<2.0×106Br(D^0 \to \mu^+\mu^-) <2.0 \times 10^{-6}.Comment: 17 pages, 4 figures (of which 1 double), paper to be submitted to Physics Letters

    Measurement of the J/Psi Production Cross Section in 920 GeV/c Fixed-Target Proton-Nucleus Interactions

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    The mid-rapidity (dsigma_(pN)/dy at y=0) and total sigma_(pN) production cross sections of J/Psi mesons are measured in proton-nucleus interactions. Data collected by the HERA-B experiment in interactions of 920 GeV/c protons with carbon, titanium and tungsten targets are used for this analysis. The J/Psi mesons are reconstructed by their decay into lepton pairs. The total production cross section obtained is sigma_(pN)(J/Psi) = 663 +- 74 +- 46 nb/nucleon. In addition, our result is compared with previous measurements
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