1,475 research outputs found

    Identities of Choi-Lee-Srivastava involving the Euler-Mascheroni’s constant

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    We give an elementary deduction of the Choi-Lee-Srivastava’s identities involving the Euler Mascheroni’s constant, thus from them is immediate the identity of Wilf

    Linearizing Control Based on Adaptive Observer for Anaerobic Continuous Sulphate Reducing Bioreactors with Unknown Kinetics

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    Anaerobic reactors are a typical example of processes that exhibit non-linear behavior and, also time varying parameters; hence their operation is known to be difficult to model and control. In contrast to modeling approaches, in practice linear controllers are widely employed for industrial processes because of their easy implementation and manipulation by plant operators; nevertheless linear approaches are not robust when the operating conditions change suddenly and/or strong disturbances are present. In order to introduce robust controllers to these processes, this paper addresses the tracking problem for the substrate (sulphate) control in a class of continuous bioreactors. An experimentally corroborated bioreactor model serves as benchmark problem for advanced non-linear analysis and control techniques; taking into account system non-linearities, stability and performance objectives over large operating regions. It is considered that, as it is common in practice, the rate of substrate consumption exhibits uncertainty. Results show that the proposed controller exhibits better dynamic performance than a classical Proportional-Integral control tuned using the methodology suggested by Internal Model Control

    MACROALGAS MARINAS DE LA BAHÍA DE SAN QUINTÍN, BAJA CALIFORNIA, MÉXICO

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    In order to know the composition anddistribution of macroalgae species in thelagoon complex of San Quintin Bay, BajaCalifornia, nine sampled were realized inthree sites during 1988, 1989, 1990, 1995 and1996; also a bibliographyc revision on themarine benthic algae cited from the studyarea. A total of 37 genera with 46 species ofmarine macroalgae were determined, ofwhich 22 are Rhodophyta, (47.82 %), 12Phaeophyta (26.08 %) and 12 Chlorophyta(26.08 %). The floristic list includes data onthe presence and distribution of speciesfound, reproductive stage, substrate and epiphytism. The families with bestrepresentation with regard to richnessand occurrence are: Corallinaceae,Ceramiaceae, Rhodomelaceae (Rhodophyta); Ectocarpaceae, Scytosiphonaceae(Phaeophyta) and Ulvaceae (Chlorophyta).18 (39.13 %) represent new records from thestudy area. Ulva expansa Linnaeus isreported for the first time for the occidentalcoast of Baja California. The floristc list andthe bibliographyc information wereactualized; the dates show that the numberod species of marine algae from San QuintinBay is composed for 59 species.Con la finalidad de determinar la distribucióny composición de las especies demacroalgas presentes en el complejolagunar de la bahía de San Quintín, BajaCalifornia, se realizaron nueve muestreos entres sitios, durante 1988, 1989, 1990, 1995 y1996; así como una revisión bibliográficade algas marinas citadas para el área deestudio. Los resultados obtenidos delmaterial recolectado indican la presencia de37 géneros con 46 especies, de las cuales22 son Rhodophyta (47.82 %), 12Phaeophyta (26.08 %) y 12 Chlorophyta(26.08 %). En la lista florística se incluyendatos sobre la presencia y distribuciónde las especies en el área de estudio,su estado reproductivo, sustrato yepifitismo. En términos de diversidadde especies, las familias mejorrepresentadas corresponden a Corallinaceae, Ceramiaceae, Rhodomelaceae(Rhodophyta), Ectocarpaceae, Scytosiphonaceae (Phaeophyta) y Ulvaceae(Chlorophyta). Del total de algasidentificadas, 18 (39.13 %) representannuevos registros para el área de estudio. Se cita por primera vez a Ulva expandaLinnaeus para la costa occidental de BajaCalifornia. Al depurar y actualizar lainformación bibliográfica desde el punto devista florístico y nomenclatural, se encontróque la flora marina conocida hasta hoy parala bahía de San Quintín es de 59 especies

    The management of lifeguards in natural acuatic spaces (beaches)

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    Este estudio nace con la necesidad de establecer criterios básicos y descripción de recomendaciones para mejorar el nivel de atención de los socorristas acuáticos profesionales en los espacios acuáticos naturales, concretamente en el trabajo realizado en las playas, con el objetivo de aumentar la seguridad de estas zonas de baño. El estudio se ha desarrollado en la Comunidad Autónoma de Cataluña, concretamente en tres playas de varios municipios de la provincia de Barcelona. Se puede afirmar que tras esta investigación la mayor parte de los socorristas acuáticos que han participado en el estudio valoraron positivamente las medidas y criterios propuestos, asumiendo que con los mismos se puede desempeñar mejor su trabajoThis study arises from the need to establish basic criteria and the description of recommendations to improve the level of responsiveness of lifeguards in natural aquatic areas, specifically in the work done on the beaches, in order to increase the safety of these bathing areas. The study was developed Cataluña, in three beaches of different municipalities in the province of Barcelona. We can aver after this research that most of the lifeguards who participated in the study value positively the proposed measures and criteria, through the assumption that these features help improve their wor

    Economic Analysis of a Pediatric Ventilator-Associated Pneumonia Prevention Initiative in Nicaragua

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    We performed an economic analysis of an intervention to decrease ventilator-associated pneumonia (VAP) prevalence in pediatric intensive care units (PICUs) at two Nicaraguan hospitals to determine the cost of the intervention and how effective it needs to be in order to be cost-neutral. A matched cohort study determined differences in costs and outcomes among ventilated patients. VAP cases were matched by sex and age for children older than 28 days and by weight for infants under 28 days old to controls without VAP. Intervention costs were determined from accounting and PICU staff records. The intervention cost was approximately 7,000foroneyear.IfVAPprevalencedecreasedby0.57,000 for one year. If VAP prevalence decreased by 0.5%, hospitals would save 7,000 and the strategy would be cost-neutral. The finding that the intervention required only modest effectiveness to be cost-neutral and has potential to generate substantial cost savings argues for implementation of VAP prevention strategies in low-income countries like Nicaragua on a broader scale

    Coastal police of Vigo; A quasi-experimental pilot study about rescue and CPR

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    El ahogamiento es una de las principales causas de muerte en el mundo y en España. Los socorristas ejercen una labor de prevención y vigilancia pero su labor es estacional y temporal. En muchos lugares, la primera respuesta a la emergencia, cuando los socorristas no están de servicio, depende de la policía, a la que se le requiere habilidades de rescate y reanimación cardiopulmonar (RCP). El objetivo de este estudio es determinar la capacidad de rescate y efecto de la fatiga sobre la calidad de la RCP de un grupo de diez policías costeros cuya área de influencia es el litoral de Vigo. El diseño fue cuasi-experimental con dos factores (pretest basal/postest rescate). Los policías pudieron realizar el rescate acuático rápido y seguro 417 ± 54,5 seg, a nivel de lactacidema se registró 12,27 ± 2,36 mmol. La fatiga inducida por el rescate afectó negativamente a la calidad de la compresiones en la RCP (p = 0,002)Drowning is a leading cause of death worldwide and in Spain. Lifeguards exert vigilance and prevention efforts but their work is seasonal and temporary. In many places the first emergency response when lifeguards are not on duty, depends on the police, which are required rescue skills and cardiopulmonary resuscitation (CPR). The objective of this study is to determine the ability of lifesaving and effect of fatigue on the quality of CPR of a group of ten coastal police whose area of influence is the coast of Vigo. The design was quasiexperimental with two factors (basal pretest / posttest rescue). Cops with basic training could perform fast and safe water rescue 417 ± 54.5 seconds, lactate level was recorded 12.27 ± 2.36 mmol. Induced fatigue during resuce effort had a nevative effect on the quality of compressions in CPR (p = 0.002

    On the use of continuous spectrum and discrete-mode differential models to predict contraction-flow pressure drops for Boger fluids

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    Over recent years, there has been slow but steady progress towards the qualitative numerical prediction of observed behaviour when highly elastic Boger fluids flow in contraction geometries. This has led to an obvious desire to seek quantitative agreement between prediction and experiment, a subject which is addressed in the current paper. We conclude that constitutive models of non-trivial complexity are required to make headway in this regard. However, we suggest that the desire to move from qualitative to quantitative agreement between theory and experiment is making real progress. In the present case with differential models, this has involved the introduction of a generalized continuous spectrum model. This is based on direct data input from material functions and rheometrical measurements. The class of such models assumes functional separability across shear and extensional deformation, through two master functions, governing independently material-time and viscous-response. The consequences of such a continuous spectrum representation are compared and contrasted against discrete-mode alternatives, via an averaged single-mode approximation and a multi-modal approximation. The effectiveness of each chosen form is gauged by the quality of match to complex flow response and experimental measurement. Here, this is interpreted in circular contraction-type flows with Boger fluids, where large experimental pressure-drop data are available and wide disparity between different fluid responses has been recorded in the past. Findings are then back-correlated to base-material response from ideal viscometric flow

    Mitochondria: An Integrative Hub Coordinating Circadian Rhythms, Metabolism, the Microbiome, and Immunity.

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    There is currently some understanding of the mechanisms that underpin the interactions between circadian rhythmicity and immunity, metabolism and immune response, and circadian rhythmicity and metabolism. In addition, a wealth of studies have led to the conclusion that the commensal microbiota (mainly bacteria) within the intestine contributes to host homeostasis by regulating circadian rhythmicity, metabolism, and the immune system. Experimental studies on how these four biological domains interact with each other have mainly focused on any two of those domains at a time and only occasionally on three. However, a systematic analysis of how these four domains concurrently interact with each other seems to be missing. We have analyzed current evidence that signposts a role for mitochondria as a key hub that supports and integrates activity across all four domains, circadian clocks, metabolic pathways, the intestinal microbiota, and the immune system, coordinating their integration and crosstalk. This work will hopefully provide a new perspective for both hypothesis-building and more systematic experimental approaches

    Shape detection algorithm applicable to solar estimation

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    [EN] This paper presents a bio-inspired hybrid algorithm for shape detection applicable to solar estimation in solar power plants. The objective is to locate and characterise the shape of a cloud over a solar power plant based on low level irradiance measurement with a small fleet of Unmanned Aerial Vehicles (UAVs) equipped with direct normal irradiance sensors. Toe hybrid algorithm takes inspiration and adapts ideas of the ant colony optimisation algorithm (ACO) and also uses a standard cover area algorithm, separating the field into two grids, one for each layer of the algorithm, to find the area affected by the cloud. Once the low irradiance zone is located by one of the UAVs, the others go to help it. This team delimits the cloud border using concepts of an image processing technique. Finally, the algorithm is tested by simulations.[ES] En este artículo se presenta un algoritmo híbrido bio-inspirado para la detección de formas aplicado a la estimación solar en plantas solares. Se tiene como objetivo localizar y caracterizar la forma de una nube sobre una planta solar basándose en medidas de niveles bajos de la irradiancia con una pequeña flota de vehículos aéreos no tripulados (UAVs en inglés) equipados con sensores capaces de medir la irradiancia directa normal. El algoritmo híbrido propuesto se inspira y adapta las ideas del algoritmo de optimización de colonia de hormigas (ant colony optimization, ACO) y también usa un algoritmo estándar de cobertura de área, separándose el campo de la planta solar en dos mallados, uno para cada capa del algoritmo, para encontrar el área afectada por la nube. Cuando un UAV localiza la zona de baja irradiancia, los otros van a ayudarle. Dicho equipo delimita el borde de la nube usando conceptos de técnicas de procesamiento de imágenes. 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