417 research outputs found

    Effect of natural zeolite on live weight changes, ruminal fermentation and nitrogen metabolism of ewe lambs

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    The objective of this study was to evaluate the effects of natural zeolite on the performance and nitrogen metabolism of Rambouillet ewe lambs. Forty Rambouillet ewe lambs with an initial weight of 41.06 ± 3.9 kg were randomly assigned to one of four experimental diets, namely 0, 20, 40 and 60 g of natural zeolite (Comercializadora OmegaŸ México) per kg dietary dry matter in a completely randomized design and sixteen ewe lambs were used in a 4 x 4 Latin square metabolism study. Performance was not modified by natural zeolite levels in the diet, and daily gain showed a quadratic response. Ammonia concentration at 8 and 12 hours increased linearly with zeolite. Zeolite increased ruminal pH linearly at 8 and 12 hours. Acetate and butyrate presented a quadratic response, and total ruminal volatile fatty acid concentration was linearly increased by zeolite. Nitrogen retention showed a linear and quadratic response to zeolite. The estimated fractions of protein digested in the small intestine, when rumen-fermentable energy was limiting (PDIE) and when rumen-fermentable nitrogen was limiting, showed a linear and quadratic response to zeolite. PDIE was positively correlated (r = 0.96) with average daily gain.Keywords: Sheep, ammonium, ruminal fermentation, productive, soluble nitroge

    MicroRNA Profiling and Bioinformatics Target Analysis in Dorsal Hippocampus of Chronically Stressed Rats: Relevance to Depression Pathophysiology

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    IndexaciĂłn: Scopus.1Laboratory of Neuroplasticity and Neurogenetics, Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, Universidad de Chile, Santiago, Chile, 2National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Durham, NC, United States, 3Centro de GenĂłmica y BioinformĂĄtica, Facultad de Ciencias, Universidad Mayor, Santiago, Chile, 4Millennium Institute for Integrative Biology (iBio), FONDAP Center for Genome Regulation, Departamento de GenĂ©tica Molecular y MicrobiologĂ­a, Pontificia Universidad CatĂłlica de Chile, Santiago, Chile, 5Department of Kinesiology, Faculty of Health Sciences, Universidad CatĂłlica del Maule, Talca, Chile, 6Escuela de QuĂ­mica y Farmacia, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile.This study was supported by the following grants: FONDECYT 1120528 (JLF), Fondo Central de InvestigaciĂłn, Universidad de Chile ENL025/16 (JLF), ES090079 (JAC). Research in RG and EV laboratories is funded by Instituto Milenio iBio – Iniciativa CientĂ­fica Milenio MINECON.Studies conducted in rodents subjected to chronic stress and some observations in humans after psychosocial stress, have allowed to establish a link between stress and the susceptibility to many complex diseases, including mood disorders. The studies in rodents have revealed that chronic exposure to stress negatively affects synaptic plasticity by triggering changes in the production of trophic factors, subunit levels of glutamate ionotropic receptors, neuron morphology, and neurogenesis in the adult hippocampus. These modifications may account for the impairment in learning and memory processes observed in chronically stressed animals. It is plausible then, that stress modifies the interplay between signal transduction cascades and gene expression regulation in the hippocampus, therefore leading to altered neuroplasticity and functioning of neural circuits. Considering that miRNAs play an important role in post-transcriptional-regulation of gene expression and participate in several hippocampus-dependent functions; we evaluated the consequences of chronic stress on the expression of miRNAs in dorsal (anterior) portion of the hippocampus, which participates in memory formation in rodents. Here, we show that male rats exposed to daily restraint stress (2.5 h/day) during 7 and 14 days display a differential profile of miRNA levels in dorsal hippocampus and remarkably, we found that some of these miRNAs belong to the miR-379-410 cluster. We confirmed a rise in miR-92a and miR-485 levels after 14 days of stress by qPCR, an effect that was not mimicked by chronic administration of corticosterone (14 days). Our in silico study identified the top-10 biological functions influenced by miR-92a, nine of which were shared with miR-485: Nervous system development and function, Tissue development, Behavior, Embryonic development, Organ development, Organismal development, Organismal survival, Tissue morphology, and Organ morphology. Furthermore, our in silico study provided a landscape of potential miRNA-92a and miR-485 targets, along with relevant canonical pathways related to axonal guidance signaling and cAMP signaling, which may influence the functioning of several neuroplastic substrates in dorsal hippocampus. Additionally, the combined effect of miR-92a and miR-485 on transcription factors, along with histone-modifying enzymes, may have a functional relevance by producing changes in gene regulatory networks that modify the neuroplastic capacity of the adult dorsal hippocampus under stress. © 2018 Muñoz-Llanos, GarcĂ­a-PĂ©rez, Xu, Tejos-Bravo, Vidal, Moyano, GutiĂ©rrez, Aguayo, Pacheco, GarcĂ­a-Rojo, Aliaga, Rojas, Cidlowski and Fiedler.https://www.frontiersin.org/articles/10.3389/fnmol.2018.00251/ful

    Acercamiento a la situacion socioeconomica de las comunidades campesinas del Departamento de Sucre desde la perspectiva del Programa Yuquero

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    An overview is given of the situation of farm communities in the dept. of Sucre, Colombia, where a cassava drying program operates. The lack of integration of the developmental activities carried out by different institutions is evident, indicating the need for greater participation in district planning. Since a trend to monocrop cassava was observed, more attention should be paid to agricultural diversification. An animal feed industry using dried cassava should be installed. Several technical aspects of agricultural production are also discussed such as mechanization, intercropping, plant density, improved technology, and income. Recommendations are also given regarding the current underutilization of the machinery of the existing agroindustries, the improvement of sanitary conditions in the plants, and the enforcement of basic industrial security measures. Product quality control should be conducted, especially regarding MC. Conditions favoring a greater participation of members in farmer organizations should be sought, in addition to enhanced institutional support in the search for a more integrated approach to regional development. (CIAT)Se presenta una percepcion global de la situacion de las comunidades campesinas del Depto. de Sucre, Colombia, donde se desarrolla un programa de secado de la yuca. Se destaca la falta de integracion de las actividades de desarrollo realizadas por diversas instituciones, lo cual indica la necesidad de una mayor participacion en la planificacion distrital. Puesto que se observo una tendencia al monocultivo de la yuca, se debe prestar mas atencion a la diversificacion agricola. Se sugiere instalar una planta para producir alimentos para animales que aproveche la yuca seca. Se discuten, ademas, varios aspectos tecnicos de la produccion agricola como mecanizacion, cultivos asociados, densidad de siembra, tecnologia mejorada e ingresos. Tambien se presentan recomendaciones sobre la actual subutilizacion de la maquinaria en las agroindustrias existentes, el mejoramiento de los servicios higienicos en las plantas y la implementacion de medidas basicas de seguridad industrial. Se debe efectuar un control de calidad del producto, especialmente en cuanto a CH. Se deben buscar las condiciones para fomentar mayor participacion de los socios en las organizaciones, ademas de incrementar el apoyo institucional en busca de un enfoque mas integrado de desarrollo a nivel regional. (CIAT

    Interference of a Tonks-Girardeau Gas on a Ring

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    We study the quantum dynamics of a one-dimensional gas of impenetrable bosons on a ring, and investigate the interference that results when an initially trapped gas localized on one side of the ring is released, split via an optical-dipole grating, and recombined on the other side of the ring. Large visibility interference fringes arise when the wavevector of the optical dipole grating is larger than the effective Fermi wavevector of the initial gas.Comment: 7 pages, 3 figure

    Kinetics of active surface-mediated diffusion in spherically symmetric domains

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    We present an exact calculation of the mean first-passage time to a target on the surface of a 2D or 3D spherical domain, for a molecule alternating phases of surface diffusion on the domain boundary and phases of bulk diffusion. We generalize the results of [J. Stat. Phys. {\bf 142}, 657 (2011)] and consider a biased diffusion in a general annulus with an arbitrary number of regularly spaced targets on a partially reflecting surface. The presented approach is based on an integral equation which can be solved analytically. Numerically validated approximation schemes, which provide more tractable expressions of the mean first-passage time are also proposed. In the framework of this minimal model of surface-mediated reactions, we show analytically that the mean reaction time can be minimized as a function of the desorption rate from the surface.Comment: Published online in J. Stat. Phy

    VDR gene polymorphisms on risk of osteoporotic hip fracture in an adult population spanish

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    La osteoporosis es una enfermedad esquelética compleja multifactorial con un fuerte componente genético, caracterizada por un deterioro en la microestructura ósea que causa fragilidad ósea y un incremento en el riesgo de fracturas osteoporóticas. El gen VDR podría estar fuertemente involucrado en el riesgo de fractura. El objetivo de este trabajo fue investigar la asociación entre polimorfismos del gen VDR y la susceptibilidad a fractura de cadera (FC). Se reclutaron 147 pacientes andaluces (102 con factores de riesgos de fracturas osteoporóticas y 45 con metabolismo óseo normal). El aislamiento de ADN se realizó a partir de 300 mL de sangre, genotipando 2 SNPs: BsmI y FokI mediante PCRRFLP (PCR-Restriction Fragment Length Polymorphism). Todas las fracturas fueron confirmadas por rayos-X mientras que el riesgo de fracturas a través de la escala FRAX y DMO. Los resultados se evaluaron estadísticamente, considerando significativo valores de p<0,05. La edad media de los pacientes fracturados fue de 68,5 años, cuyas frecuencias alélicas fueron 64.7% G y 68.6% C para BsmI y FokI, respectivamente. La prevalencia de estos SNPs en la población caso fueron: 43,3% GA, 43.3% GG y 13,7% AA para BsmI y 49,0% CC, 39,20% CT, 11,8% TT para FokI. Las frecuencias de los alelos y genotipos no mostraron diferencias entre pacientes con riesgo de fracturas y pacientes control. Las frecuencias estån acorde con las demostradas en HapMap para población europeacaucåsica. No se encontró ninguna asociación significativa entre estos SNPs y la susceptibilidad a las FC en la población adulta andaluza.Osteoporosis is a multifactorial complex skeletal disease with strong genetic component, characterized by a deterioration of bone microstructure that causes bone fragility and an increased risk of osteoporotic fractures. VDR gene could be strongly involved in the risk of fracture. The aim of this study was to investigate the association between VDR gene polymorphisms and susceptibility to hip fracture (HF). 147 Andalusian patients were recruited (102 with risk factors for osteoporotic fractures and 47 with normal bone metabolism). DNA isolation was performed from 300 mL of blood, genotyping 2 SNPs: BsmI and FokI by PCR-RFLP (PCR-Restriction Fragment Length Polymorphism). All fractures were confirmed by X-rays while the risk of fractures through FRAX level and BMD. The results were statistically evaluated, considering significant p-values <0.05. The average age of fractured patients was 68.5 years, whose allele frequencies were 64.7% G and 68.6% C for BsmI and FokI, respectively. Prevalence of these SNPs in the case population were: 43.3% GA, 43.3% GG and 13.7% AA BsmI and 49.0 % CC, 39.2% CT, 11.8% TT for FokI. The frequencies of alleles and genotypes showed no differences between patients with and without risk of hip fracture. The frequencies are agree to HapMap for European-Caucasian population. It was found no significant association between these SNPs and susceptibility to HF in the adult population of Andalusia

    Aumento de producciĂłn de lĂ­neas de trigo panadero con los genes H27 y H30 que confieren resistencia a Mayetiola destructor Say., transferidos desde Aegilops spp

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    Los resultados obtenidos en un ensayo de campo de una colecciĂłn de lĂ­neas avanzadas de trigo con introgresiĂłn de los genes H27 y H30, que confieren resistencia frente al Mosquito del trigo (Mayetiola destructor), evidenciaron que alguna de estas lĂ­neas mejoraban significativamente la producciĂłn (142%) respecto al testigo susceptible, indicando su posible utilidad como variedades capaces de dar buen rendimiento en ausencia de tratamientos quĂ­micos (insecticidas) contra la plaga del mosquit

    Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

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    We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at lg⁡(E/eV)=18.5−19.0\lg(E/{\rm eV})=18.5-19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A > 4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

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    Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius AA. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio
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