332 research outputs found

    Latin America and the international economic CRISIS: THE TRADE CHANNEL

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    ResumenEsta investigación propone una vía para la evaluación del impacto de corto plazo quela crisis financiera y económica internacional, transmitida esencialmente a través delcanal comercial, puede tener sobre un conjunto de ocho economías latinoamericanas.Para el efecto se emplea un modelo del sector real, el modelo GTAP, caracterizadopor ser de alcance global y operar bajo el supuesto de retornos constantes a escala.La estrategia de modelación se basa en la implementación de un choque negativo a ladotación de capital de las economías de Estados Unidos y la Unión Europea, de formatal que se genere un decrecimiento del PIB similar al pronosticado para 2009 por elFMI. Los principales resultados muestran un esperado y generalizado efecto negativosobre el PIB. Sin embargo, su intensidad no necesariamente depende del grado dedependencia comercial de las economías con respecto a Estados Unidos y la UniónEuropea. La composición sectorial del comercio tiene importancia. Otro tanto sucedecon el comportamiento de los precios internacionales. A pesar de que el impacto de lacrisis sobre el valor de los flujos comerciales luce relativamente moderado, la caídadel PIB tiende a ser mayor y no es desdeñable. No obstante, cuando el impacto semide en términos de bienestar resulta ser más bien moderado.Palabras clave: comercio internacional, la crisis mundial, Colombia, de equilibriogeneral computable.International trade, Global crisis, Colombia, Computable General Equilibrium

    Cyanolipids from Sapindus saponaria L. seeds oil

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    The chemical composition of the oil extracted from the seeds of Sapindus saponaria L., (Sapindaceae), was investigated. Cyanolipids constituted 5% hexane extract of the seeds, whereas triacylglycerols (TAG) accounted for 90%. The oil contains type III cyanolipids (CL) 1-cyano-2-hydroxymethylprop-1-en-3-ol-diesters. Structural investigation of the oil components was accomplished by chemical, chromatographic (TLC, CC, GC-MS), and spectroscopic (IR, NMR) means. GC-MS analysis showed that fatty acids were dominant in the CL components of the oil from S. saponaria L., with cis-11-eicosenoic acid, cis-11-octadecenoic acid and eicosanoic acid as the only esterified fatty acyl chains respectively. This being the first report of this kind of natural products (CL), located in the seeds of this plant

    Gut microbiota disturbance during helminth infection: can it affect cognition and behaviour of children?

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    Background: Bidirectional signalling between the brain and the gastrointestinal tract is regulated at neural, hormonal, and immunological levels. Recent studies have shown that helminth infections can alter the normal gut microbiota. Studies have also shown that the gut microbiota is instrumental in the normal development, maturation and function of the brain. The pathophysiological pathways by which helminth infections contribute to altered cognitive function remain poorly understood. Discussion: We put forward the hypothesis that gastrointestinal infections with parasitic worms, such as helminths, induce an imbalance of the gut-brain axis, which, in turn, can detrimentally manifest in brain development. Factors supporting this hypothesis are: 1) research focusing on intelligence and school performance in school-aged children has shown helminth infections to be associated with cognitive impairment, 2) disturbances in gut microbiota have been shown to be associated with important cognitive developmental effects, and 3) helminth infections have been shown to alter the gut microbiota structure. Evidence on the complex interactions between extrinsic (parasite) and intrinsic (host-derived) factors has been synthesised and discussed. Summary: While evidence in favour of the helminth-gut microbiota-central nervous system hypothesis is circumstantial, it would be unwise to rule it out as a possible mechanism by which gastrointestinal helminth infections induce childhood cognitive morbidity. Further empirical studies are necessary to test an indirect effect of helminth infections on the modulation of mood and behaviour through its effects on the gut microbiota

    Tylopilus dunensis (Boletaceae, Basidiomycota): notes on morphological, phylogenetical and distributional aspects

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    Tylopilus is a worldwide distributed genus of boletes with about 100 known taxa, of which at least 16 are from Brazil and Guyana. Tylopilus dunensis, a species originally described from sand dune habitats in the state of Rio Grande do Norte in northeastern Brazil, has now been recovered in a ‘tabuleiro’ (i.e., tableland forest) from Paraíba. The main phenetic features of this still poorly known species are the orange to orange-ochraceous pileus with yellowish brown margins, unchanging pileus context, the pale cream hymenophore with wide pores, the yellowish stipe, the small and narrow basidiospores, and the long and frequent dextrinoid pseudocystidioid pleurocystidia. After the discovery of the phylloporoid tube trama in our specimens, we emended tube trama type of T. dunensis

    Contribution of Yap 1 towards S. cervisiae adaptation to arsenic mediated oxidative stress

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    Post-PrintIn the budding yeast Saccharomyces cerevisiae arsenic detoxification involves the activation Yap8, a member of the Yap family of transcription factors, which in turn regulates ACR2 and ACR3, encoding an arsenate reductase and a plasma membrane arsenite efflux-protein, respectively. In addition, Yap1 is involved in the arsenic adaptation process through regulating the expression of the vacuolar-pump encoded by YCF1 and also contributing to the regulation of ACR genes. Here we show that Yap1 is also involved in the removal of ROS generated by arsenic compounds. Data on lipid peroxidation and intracellular oxidation indicate that deletion of YAP1 and YAP8 triggers cellular oxidation mediated by inorganic arsenic. In spite of the increased amounts of As(III) absorbed by the yap8 mutant, the enhanced transcriptional activation of the antioxidant genes such as GSH1, SOD1 and TRX2 may prevent protein oxidation. In contrast, the yap1 mutant exhibits high contents of protein carbonyl groups and the GSSG:GSH ratio is severely disturbed upon exposure to arsenic compounds in these cells. These results point to an additional level of Yap1 contribution to arsenic stress responses by preventing oxidative damage in cells exposed to these compounds. Transcriptional profiling revealed that genes of the functional categories related with sulphur and methionine metabolism and with the maintenance of the cell redox homeostasis are activated to mediate adaptation of the wild type strain to 2 mM arsenate treatmen

    Cryopreservation of caprine ovarian tissue using glycerol and ethylene glycol

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    Cryopreservation of ovarian tissue may be a potential alternative for the conservation of genetically superior animals, including high milk- and meat-producing goat breeds. However, until now, no information was available concerning the cryopreservation of preantral follicles (PF) enclosed in caprine ovarian tissue. The objective of the present study was to evaluate the structural and ultrastructural characteristics of caprine PF after exposure to and cryopreservation of ovarian tissue in 1.5 and 3 M glycerol (GLY) and ethylene glycol (EG). At the slaughterhouse, each ovarian pair from five adult mixed breed goats was divided into nine fragments and randomly distributed into treatment groups. One fragment was immediately fixed for histological examination and ultrastructural analysis, after slaughter (control). Four of the ovarian fragments were equilibrated at 20 °C for 20 min in 1.8 ml of MEM containing 1.5 or 3 M GLY or EG for a toxicity test and the final four fragments were slowly frozen using these cryoprotectants at the concentrations above. After toxicity testing and freezing/thawing, the ovarian fragments were fixed for histological examination. Histological analysis showed that after toxicity testing and cryopreservation of the ovarian tissue in GLY or EG at both concentrations, the percentage of normal PF was significantly lower than controls. Ultrastructural analysis of PF frozen in 1.5 and 3 M GLY, as well as 3 M EG demonstrated that these follicles remained morphologically normal. In conclusion, we demonstrated cryopreservation of caprine PF in ovarian tissue

    Observation of γ-delayed 3α breakup of the 15.11 and 12.71 MeV states in 12C

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    6 pags., 4 figs., 2 tabs. -- PACS:27.20.+n25.55.Hp23.20.-g29.85.-cThe reactions 10B (3He, p α α α) at 4.9 MeV and 11B (3He, d α α α) at 8.5 MeV have been used to investigate the γ decay of states in 12C. By measuring the four-body final state in complete kinematics we are able to detect γ transitions indirectly. We find γ transitions from the 15.11 MeV state in 12C to the 12.71, 11.83, 10.3 and 7.65 MeV states followed by their breakup into three α particles. The relative γ-ray branching ratios obtained are (1.2 ± 0.3), (0.32 ± 0.12), (1.4 ± 0.2) and (4.4 ± 0.8) %, respectively, with the remaining (92.7 ± 1.0) % of the γ decays going to the bound states. We obtain Γα / Γ = (2.8 ± 1.2) % for the isospin-forbidden α decay of the 15.11 MeV state. From the 12.71 MeV state we find γ transitions to the 10.3 and 7.65 MeV states. The relative γ-ray branching ratios are (0.9- 0.5 + 0.6) and (2.6- 1.2 + 1.6) %, respectively, with the remaining (96.6- 1.3 + 1.7) % of the γ decays going to the bound states. Finally, we discuss the relation between the β decay of 12N and 12B to states in 12C and the γ decay of the 15.11 MeV analog in 12C to the same states. © 2009 Elsevier B.V.We would like to acknowledge the support of the Spanish CICYT research grant FPA2007-62170 and the MICINN Consolider Project CSD 2007-00042 as well as the support of the European Union VI Framework through RII3-EURONS/JRA4-DLEP (contract number 506065). D.G. is a Juan de la Cierva fellow

    Post-harvest quality of fresh-marketed tomatoes as a function of harvest periods

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    Losses on tomato business chain start at harvest, a two-months period. At the beginning of the harvest, fruits concentrate at the basal part of the plant, then in the middle, and finally at the top, and undergo changes in diameter and maturity indexes as harvest progresses. The aim of this work was to evaluate the impact of handling at three different periods: (I) 15 days, (II) 30 days, and (III) 45 days after the beginning of harvest. Tomatoes were ordinarily grown and harvested in to bamboo baskets, and transferred to plastics boxes. Fruits were classified according to ripening stage and diameter, and evaluated for mechanical damage and external defects caused by harvesting procedures. The time required for the harvest operation was measured; damage to fruits (%) and weight loss (%), caused either in the field and/or during the harvesting process, were taken into consideration and related to the final quality of fruit after storage for 21 days. The same methodology was used all through the production and harvest cycle. The highest % fruit damage occurred during period II, a longer harvest time than the other two periods. Fruits not submitted to handling showed lower weight loss than handled fruits. Fruits harvested in period II and stored for 21 days showed higher losses due to mechanical injury

    Diluted Magnetic Semiconductors Nanocrystals: Saturation and Modulation

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    Diluted Magnetic Semiconductor (DMS) nanocrystals are a new class of materials formed by doping the semiconductor with transition metals (TM), which gives interesting magneto-optical properties. These properties are attributed to the exchange interaction between the pure semiconductor’s sp-electrons and the localized TM d-electrons. This book chapter shows exciting results of new DMS developed by the group, both in powder form and embedded in glassy systems. Depending on the concentration of doping ions, saturation of the incorporation of substitutional and interstitial sites in the nanocrystal structure may occur, forming other nanocrystals. In this context, we investigated the doping saturation limit in nanopowders of DMS Zn1-xMnxO NCs and Zn1-xMnxTe, Zn0.99-xMn0.01CoxTe, and Bi2-xCoxS NCs synthesized in glassy matrices. Thus, the sites’ saturation into the crystalline lattice of nanocrystals is a topic little reported in the literature, and we will comment on this work. Therefore, we will show results from the group about the modulation and saturation in diluted magnetic semiconductors nanocrystals in this work
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