230 research outputs found

    In vitro gas production kinetics and degradability of a diet for growing lambs: effect of fibrolytic enzyme products at different dose levels

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    The objective of this study was to evaluate the effects of three fibrolytic enzyme products (cellulase (CEL), xylanase (XYL) and a 1:1 mixture of CEL and XYL (MIX)) at three dose levels (0, 1 and 3 lL/0.5 g DM) on the in vitro fermentation of a diet for growing lambs. Bottles were incubated for 96 h at 39 C. A mathematical model was used to estimate the parameters describing the gas production (GP) curve (b, c and L). Dry matter degradability (DMD) and fibre (NDFD and ADFD) degradability were determined at the end of the incubation period. Metabolisable energy (ME) and short chain fatty acids (SCFA) were calculated at 24 h of incubation. The asymptotic GP (parameter b) was affected (p<0.02) by enzyme product and dose level, with a significant linear response (p<0.05). Dose level affected ME and SCFA with a significant linear (p<0.05) and quadratic (p<0.01) response. The interaction between enzyme product and dose level was significant (p<0.05) for cumulative GP up to 72 and 96 h of incubation, pH, ADFD and DMD. The results suggest that application of exogenous cellulases has the potential to alter asymptotic GP and degradability of ADF and DM of a diet for growing lambs, but most of the results depend on the interaction between enzyme product and dose level. Future studies are required to determine the ideal combination between enzyme product and dose level for optimal degradation of ruminant feeds

    Effects of exogenous enzymes and application method on nutrient intake, digestibility and growth performance of Pelibuey lambs

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    Pelibuey sheep is the main breed in the tropical and subtropical regions of Mexico, and high demand of sheep meat has favored the finishing of lambs in feedlots with diets containing high levels of grains. The objective of this study was to evaluate the effects of exogenous enzymes (EE) and application method on nutrient intake and digestibility and performance of growing Pelibuey lambs. Treatments were based on comparison of two different methods of adding an enzyme product (sprayed on the total mixed ration or applied orally to the lambs) versus control treatment (no added enzyme). Twenty-one Pelibuey lambs, weighing 15.7 kg (SD = 1.8 kg) initial body weight, were individually housed in shaded pens and assigned randomly to one of the three enzyme treatments. At the end of study (lasting for 45 days), three lambs from each treatment were randomly selected and adapted to a pants and harness designed for fecal collection to measure nutrient digestibilities. Total body gain and average daily gain were affected (P < 0.05) by supplemental EE. The application method of EE had significant (P < 0.05) effect on FCE and FCR, but no effects were observed on nutrient intake. Supplemental EE did improve (P < 0.05) the digestibilities of dry matter, organic matter, neutral and acid detergent fiber, but no differences were observed in crude protein digestibility. The application method of EE had significant (P < 0.05) effect on the digestibility of acid detergent fiber. Supplemental EE can improve body weight gain and nutrient digestibilities without affecting nutrient intake in Pelibuey lambs, but the results of feed conversion efficiency and acid detergent fiber digestibility depend on the application method used of the EE

    A qualitative study about immigrant workers’ perceptions of their working conditions in Spain

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    Background: Spain has recently become an inward migration country. Little is known about the occupational health of immigrant workers. This study aimed to explore the perceptions that immigrant workers in Spain had of their working conditions. Methods: Qualitative, exploratory, descriptive study. Criterion sampling. Data collected between September 2006 and May 2007 through semi-structured focus groups and individual interviews, with a topic guide. One hundred and fifty-eight immigrant workers (90 men/68 women) from Colombia (n = 21), Morocco (n = 39), sub-Saharan Africa (n = 29), Romania (n = 44) and Ecuador (n = 25), who were authorised (documented) or unauthorised (undocumented) residents in five medium to large cities in Spain. Results: Participants described poor working conditions, low pay and health hazards. Perception of hazards appeared to be related to gender and job sector. Informants were highly segregated into jobs by sex, however, so this issue will need further exploration. Undocumented workers described poorer conditions than documented workers, which they attributed to their documentation status. Documented participants also felt vulnerable because of their immigrant status. Informants believed that deficient language skills, non-transferability of their education and training and, most of all, their immigrant status and economic need left them with little choice but to work under poor conditions. Conclusions: The occupational health needs of immigrant workers must be addressed at the job level, while improving the enforcement of existing health and safety regulations. The roles that documentation status and economic need played in these informants’ work experiences should be considered and how these may influence health outcomes.Garcia Garcia, Ana Maria, [email protected]

    High-level synthesis of switched-capacitor, switched-current and continuous-time ΣΔ modulators using SIMULINK-based time-domain behavioral models

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    This paper presents a high-level synthesis tool for ΣΔ Modulators (ΣΔMs) that combines an accurate SIMULINK-based time-domain behavioral simulator with a statistical optimization core. Three different circuit techniques for the modulator implementation are considered: switched-capacitor, switched-current and continuous-time. The behavioral models of these circuits, that take into account the most critical limiting factors, have been incorporated into the SIMULINK environment by using S-function blocks, which drastically increase the computational efficiency. The precision of these models has been validated by electrical simulations using HSPICE and experimental measurements from several silicon prototypes. The combination of high accuracy, short CPU time and interoperability of different circuit models together with the efficiency of the optimization engine makes the proposed tool an advantageous alternative for ΣΔM synthesis. The implementation on the well-known MATLAB/SIMULINK platform brings numerous advantages in terms of data manipulation, processing capabilities, flexibility and simulation with other electronic subsystems. Moreover, this is the first tool dealing with the synthesis of ΣΔMs using both discrete-time and continuous-time circuit techniques.This work was supported by the EU IST Project 2001-34283/TAMES-2 and by the Spanish Ministry of Science and Education (with support from the European Regional Development Fund) under Contract TIC2001-0929 ADAVERE and TEC2004-01752/MIC.Peer reviewe

    Synthesis and characterization of PtTe₂ multi-crystallite nanoparticles using organotellurium nanocomposites

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    Herein, we report the synthesis of new PtTe₂ multi-crystallite nanoparticles (NPs) in different sizes through an annealing process using new nanostructured Pt-Te organometallic NPs as a single source precursor. This precursor was obtained in a single reaction step using Ph₂Te₂ and H₂PtCl₆ and could be successfully size controlled in the nanoscale range. The resulting organometallic composite precursor could be thermally decomposed in 1,5 pentanediol to yield the new PtTe₂ multi-crystallite NPs. The final size of the multi-crystallite spheres was successfully controlled by selecting the nanoprecursor size. The sizes of the PtTe₂ crystallites formed using the large spheres were estimated to be in the range of 2.5-6.5 nm. The results provide information relevant to understanding specific mechanistic aspects related to the synthesis of organometallic nanomaterials and nanocrystals based on platinum and tellurium

    La revisión excepcional de precios en Obra Pública. Actualización legislativa 2022

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    Dentro de las tipologías de contratación de bienes o servicios por parte de la Administración Pública, la contratación de obras establece una serie de particularidades que conllevan el tratamiento singularizado del Contrato de Obras. La implantación del Registro de Contratos del Sector Público permite analizar los datos del mismo para la obtención de una imagen del estado actual de la materia. Hoy en día los contratos de obra representan al menos el 20% del importe total contratado por las Administraciones Públicas, aumentado este porcentaje hasta un 22.8% si se incluyen la concesión de obra pública. Atendiendo a los procedimientos de contratación, el procedimiento abierto es el más utilizado, representa el 49,7% de los contratos. Le sigue en importancia el procedimiento negociado (35,2%), teniendo los demás procedimientos un menor peso. Otro dato importante para tener en cuenta es el importe medio de las distintas tipologías contractuales que permita establecer el orden de magnitud de cada una de ellas. Es significativamente más elevado en el ámbito de la Administración General, principalmente por las grandes infraestructuras que acomete el Estado en materia de carreteras, ferrocarriles, puertos, etc. De los datos expuestos anteriormente se aprecia la importancia que tiene la contratación pública de obras dentro del tejido productivo del país en todos sus niveles. La aparición de circunstancias extraordinarias, como la pandemia desatada por el virus SARS-CoV-2, ha tenido una repercusión directa en el contexto económico y ha derivado en una rotura de las cadenas logísticas, además del aumento exponencial del coste de las materias primas. Como el resto del entorno económico del país, la contratación de obra pública se ha visto gravemente afectada por el encarecimiento de las materias primas. En concreto, los contratistas han visto como el equilibrio económico, en el que se fundamenta la ejecución de este tipo de contratos, ha desaparecido y excedido el principio de riesgo y ventura que deben soportar. La aparición de estas circunstancias era del todo imposible de prever en los procedimientos administrativos en los que se licitaron los contratos y ha derivado en la imposibilidad material de ejecutarlos. El legislador estatal, ante la gravedad de la situación y en el uso de sus facultades competenciales, para atajar la problemática y mitigar los efectos del incremento de costes en las obras, ha optado por la creación de un mecanismo de revisión excepcional de los precios de obra pública y dotado a las comunidades autónomas la potestad de adscribirse, adaptarlo y complementarlo

    Association between tomato consumption and blood pressure in an older population at high cardiovascular risk: observational analysis of PREDIMED trial

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    Aims: Clinical studies have produced conflicting evidence on the effects of the consumption of tomatoes on blood pressure, and there are limited data from epidemiologic studies. This study assesses whether tomato consumption (Solanum lycopersicum L.) is associated with Systolic (SBP) and Diastolic Blood Pressure (DBP), and the risk of hypertension in a prospective 3-year longitudinal study in older adults at high cardiovascular risk.Methods: The present study was carried out within the PREDIMED (Prevención con Dieta Mediterránea) trial involving 7,056 (82.5% hypertensive) participants. The consumption of tomato (g/d) was measured using a validated Food Frequency Questionnaire (FFQ) and categorized into 4 groups: lowest (110 g). Multilevel linear mixed models examined blood pressure and tomato consumption association. Cox proportional-hazards models analyzed hypertension risk in 1,097 non-hypertensive participants, studying risk reductions versus the lowest tomato consumers.Results: An inverse association between tomato consumption and diastolic blood pressure was observed between the intermediate group β = -0.65 mmHg [95% CI:-1.20, -0.10] and the lowest consumption group. A significant inverse association was observed for blood pressure in grade 1 hypertension participants in the intermediate tomato consumption group. The risk of hypertension decreased with consumption of >110 g/d tomato (highest vs lowest consumption; HR, 0.64 [95% CI, 0.51-0.89]).Conclusions: Tomato consumption, including tomato-based products, is beneficial in preventing and managing hypertension. Higher tomato intake reduces hypertension risk by 36%, and moderate consumption lowers blood pressure, especially in grade 1 hypertension.</p

    Renovación del sistema de información docente de la Facultad de Informática

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    Memoria del proyecto Innova-Gestión 301 de la convocatoria 2019/2020 "Renovación del sistema de información docente de la Facultad de Informática" que consistía en la implementación de una primera versión de sistema de información interno para la gestión de horarios, fichas docentes, tutorías y otros datos relevantes para la docencia para ser utilizado en la facultad de informática

    The structural assembly switch of cell division protein FtsZ probed with fluorescent allosteric inhibitors

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    FtsZ is a widely conserved tubulin-like GTPase that directs bacterial cell division and a new target for antibiotic discovery. This protein assembly machine cooperatively polymerizes forming single-stranded filaments, by means of self-switching between inactive and actively associating monomer conformations. The structural switch mechanism was proposed to involve a movement of the C-terminal and N-terminal FtsZ domains, opening a cleft between them, allosterically coupled to the formation of a tight association interface between consecutive subunits along the filament. The effective antibacterial benzamide PC190723 binds into the open interdomain cleft and stabilizes FtsZ filaments, thus impairing correct formation of the FtsZ ring for cell division. We have designed fluorescent analogs of PC190723 to probe the FtsZ structural assembly switch. Among them, nitrobenzoxadiazole probes specifically bind to assembled FtsZ rather than to monomers. Probes with several spacer lengths between the fluorophore and benzamide moieties suggest a binding site extension along the interdomain cleft. These probes label FtsZ rings of live Bacillus subtilis and Staphylococcus aureus, without apparently modifying normal cell morphology and growth, but at high concentrations they induce impaired bacterial division phenotypes typical of benzamide antibacterials. During the FtsZ assembly-disassembly process, the fluorescence anisotropy of the probes changes upon binding and dissociating from FtsZ, thus reporting open and closed FtsZ interdomain clefts. Our results demonstrate the structural mechanism of the FtsZ assembly switch, and suggest that the probes bind into the open clefts in cellular FtsZ polymers preferably to unassembled FtsZ in the bacterial cytosol

    Modelos de crecimiento y producción en España: historia, ejemplos contemporáneos y perspectivas

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    [EN] In this paper we present a review of forest models developed in Spain in recent years for both timber and non timber production and forest dynamics (regeneration, mortality). Models developed are whole stand, size (diameter) class and individual-tree. The models developed to date have been developed using data from permanent plots, experimental sites and the National Forest Inventory. In this paper we show the different sub-models developed so far and the friendly use software. Main perspectives of forest modeling in Spain are presented[ES] En el presente trabajo se presenta una revisión sobre los modelos forestales desarrollados en España durante los últimos años, tanto para la producción maderable como no maderable y, para la dinámica de los bosques (regeneración, mortalidad). Se presentan modelos tanto de rodal completo como de clases diamétricas y de árbol individual. Los modelos desarrollados hasta la fecha se han desarrollado a partir de datos procedentes de parcelas permanentes, ensayos y el Inventario Forestal Nacional. En el trabajo se muestran los diferentes submodelos desarrollados hasta la fecha, así como las plataformas informáticas que permiten utilizar dichos modelos. Se incluyen las principales perspectivas de desarrollo de la modelización forestal en EspañaSIThe models described in this paper were funded by different regional, national and European projects, and some of them were elaborated by the authors. This work was funded by the Spanish Government by the SELVIRED network (code AGL2008-03740) and the strategic project «Restauración y Gestión Forestal» (code PSE-310000-2009-4
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