A method for the simultaneous determination of transport and structural parameters of forward osmosis membranes

We present a simple and rapid methodology to characterize the water and solute permeability coefficients (A and B, respectively) and structural parameter (S) of forward osmosis (FO) membranes. The methodology comprises a single FO experiment divided into four stages, each using a different concentration of draw solution. The experimental water and reverse salt fluxes measured in each stage are fitted to the corresponding FO transport equations by performing a least-squares non-linear regression, using A, B, and S as regression parameters. Hand-cast thin-film composite (TFC) FO membranes and commercial TFC FO, TFC reverse osmosis (RO), and cellulose acetate-based asymmetric FO membranes are evaluated following this protocol. We compare the membrane properties obtained with our FO-based methodology with those derived from existing protocols based on an RO experiment followed by an FO experiment. For all membranes, the FO-based protocol gives more accurate predictions of the water and salt fluxes than the existing method. The numerical robustness of the method and the sensitivity of the regression parameters to random errors in the measured quantities are thoroughly analyzed. The assessment shows that confidence in the accuracy of the determined membrane parameters can be enhanced by simultaneously achieving close fitting of the predicted fluxes to experimental measurements (i.e., high R2 values) and constant water to salt flux ratios in each stage. Additionally, the existing and proposed approaches yield consistently dissimilar results for some of the analyzed membranes, indicating a discrepancy that might be attributed to the different driving forces utilized in RO and in FO that should be further investigated

The nature of transition circumstellar disks III: Perseus, Taurus, and Auriga

As part of an ongoing program aiming to characterize a large number of Spitzer-selected transition disks (disks with reduced levels of near-IR and/or mid-IR excess emission), we have obtained (sub)millimeter wavelength photometry, high-resolution optical spectroscopy, and adaptive optics near-infrared imaging for a sample of 31 transition objects located in the Perseus, Taurus, and Auriga molecular clouds. We use these ground-based data to estimate disk masses, multiplicity, and accretion rates in order to investigate the mechanisms potentially responsible for their inner holes. Following our previous studies in other regions, we combine disk masses, accretion rates, and multiplicity data with other information, such as spectral energy distribution morphology and fractional disk luminosity, to classify the disks as strong candidates for the following categories: grain-growth-dominated disks (seven objects), giant planet-forming disks (six objects), photoevaporating disks (seven objects), debris disks (11 objects), and cicumbinary disks (one object, which was also classified as a photoevaporating disk). Combining our sample of 31 transition disks with those from our previous studies results in a sample of 74 transition objects that have been selected, characterized, and classified in a homogenous way. We discuss this combined high-quality sample in the context of the current paradigm of the evolution and dissipation of protoplanetary disks and use its properties to constrain different aspects of the key processes driving their evolution. We find that the age distribution of disks that are likely to harbor recently formed giant planets favors core accretion as the main planet formation mechanism and a 2-3Myr formation timescale.Facultad de Ciencias Astronómicas y Geofísica

Evaluación de la calidad de leches crudas en tres subregiones del departamento de Sucre, Colombia

The objective was to evaluate the physicochemical, microbiological quality, somatic cell count and presence of inhibitors in raw milks in the department of Sucre. 150 samples of raw milk from six storage centers or processing plants from three subregions of the department of Sucre (Sabanas, San Jorge and Gulf of Morrosquillo) were taken using a descriptive cross-sectional study. 25 samples in each collection center that correspond to 25 producers from the different subregions of the department were taken. Microbiological and physiochemical parameters and udder health were determined of a total of 50 samples for each subregion. The data obtained were analyzed according to accepted standards in Colombia. For the most part of the physicochemical parameters, were within the accepted values established in decree 616 of 2006 and decree 1880of 2011(protein ?2.9%, fat ?3.0%, density (15oC) ?1.030, TS ?11.30, SNF ?8.30). The count of colony forming units (CFU/mL) in the different subregions was greater than 600,000 CFU/mL. The somatic cell count (SCC/mL) was greater than 500,000 SCC/mL. In 8% of the sampled milks showed presence of inhibitors. Overall, the raw milk had good physicochemical quality but, the microbiological quality and health of the udder were poor, which requires immediate implementation of programs in order to obtain high quality hygienic milk.El objetivo fue evaluar la calidad fisicoquímica, microbiológica, recuento de células somáticas y presencia de inhibidores en leches crudas en el departamento de Sucre. Mediante un estudio descriptivo de corte transversal, se tomaron 150 muestras de leche cruda procedentes de seis centros de acopio o plantas procesadoras de tres subregiones del departamento de Sucre (Sabanas, San Jorge y Golfo del Morrosquillo). En cada centro de acopio se tomaron 25 muestras que correspondieron a 25 productores de las diferentes subregiones del departamento, para un total de 50 muestras por cada subregión. Se determinaron parámetros fisicoquímicos, microbiológicos y de sanidad de la ubre. Los datos obtenidos se analizaron de acuerdo a la normatividad vigente en Colombia. Los parámetros fisicoquímicos en su mayoría se hallaron dentro de los valores aceptados establecidos en el decreto 616 de 2006 y el decreto 1880 de 2011(proteína ?2,9%, grasa ?3,0%, densidad (15oC) ?1.030, ST ?11,30, SNG ?8,30). El recuento de unidades formadoras de colonias (UFC/mL) en las diferentes subregiones fue mayor a 600.000. El recuento de células somáticas (RCS/mL) fue mayor a 500.000. En el 8% de las leches muestreadas se encontró presencia de inhibidores. Se encontró buena calidad fisicoquímica, sin embargo la calidad microbiológica y la sanidad de la ubre son deficientes, lo que requiere de implementación inmediata de programas para la obtención de leches de buena calidad higiénica

Respuesta transitoria del tren de potencia de un vehículo

La simulación es una tarea importante para predecir y diagnosticar la respuesta del automóvil a las perturbaciones. La principal contribución de este artículo es un modelo para el sistema de potencia de un automóvil de tracción trasera y el análisis de su respuesta transitoria. La simulación muestra la influencia de los parámetros de los componentes del tren de potencia en la respuesta del sistema a una entrada en escalón originada en la volante del motor

Respuesta transitoria del tren de potencia de un vehículo

La simulación es una tarea importante para predecir y diagnosticar la respuesta del automóvil a las perturbaciones. La principal contribución de este artículo es un modelo para el sistema de potencia de un automóvil de tracción trasera y el análisis de su respuesta transitoria. La simulación muestra la influencia de los parámetros de los componentes del tren de potencia en la respuesta del sistema a una entrada en escalón originada en la volante del motor

Respuesta transitoria del tren de potencia de un vehículo

La simulación es una tarea importante para predecir y diagnosticar la respuesta del automóvil a las perturbaciones. La principal contribución de este artículo es un modelo para el sistema de potencia de un automóvil de tracción trasera y el análisis de su respuesta transitoria. La simulación muestra la influencia de los parámetros de los componentes del tren de potencia en la respuesta del sistema a una entrada en escalón originada en la volante del motor

2-DE proteomics analysis of drought treated seedlings of Quercus ilex supports a root active strategy for metabolic adaptation in response to water shortage

Holm oak is a dominant tree in the western Mediterranean region. Despite being well adapted to dry hot climate, drought is the main cause of mortality post-transplanting in reforestation programs. An active response to drought is critical for tree establishment and survival. Applying a gel-based proteomic approach, dynamic changes in root proteins of drought treated Quercus ilex subsp. Ballota [Desf.] Samp. seedlings were followed. Water stress was applied on 20 day-old holm oak plantlets by water limitation for a period of 10 and 20 days, each followed by 10 days of recovery. Stress was monitored by changes in water status, plant growth, and electrolyte leakage. Contrary to leaves, holm oak roots responded readily to water shortage at physiological level by growth inhibition, changes in water status and membrane stability. Root proteins were extracted using trichloroacetate/acetone/phenol protocol and separated by two-dimensional electrophoresis. Coomassie colloidal stained gel images were analyzed and spot intensity data subjected to multivariate statistical analysis. Selected consistent spots in three biological replicas, presenting significant changes under stress, were subjected to MALDI-TOF mass spectrometry (peptide mass fingerprinting and MS/MS). For protein identification, combined search was performed with MASCOT search engine over NCBInr Viridiplantae and Uniprot databases. Data are available via ProteomeXchange with identifier PXD002484. Identified proteins were classified into functional groups: metabolism, protein biosynthesis and proteolysis, defense against biotic stress, cellular protection against abiotic stress, intracellular transport. Several enzymes of the carbohydrate metabolism decreased in abundance in roots under drought stress while some related to ATP synthesis and secondary metabolism increased. Results point at active metabolic adjustment and mobilization of the defense system in roots to actively counteract drought stress

Integración de dispositivos de salud personal en la plataforma de telecuidado para diabetes PERSONA

La plataforma de telecuidado PERSONA se ha desarrollado en el marco del CIBER-BBN y tiene por objetivo soportar el autocuidado diario de pacientes con diabetes tipo 1. La plataforma proporciona acceso a herramientas de soporte a la decisión, de procesado automático de la información, de monitorización de las variables que afectan a la enfermedad y facilita la comunicación entre los agentes involucrados en el cuidado del paciente. La integración de dispositivos médicos interoperables es un requisito principal de la plataforma PERSONA. En este trabajo presentamos las soluciones adoptadas en cuanto a la integración de dispositivos médicos y analizamos las características de los protocolos de comunicación inalámbrica de los dispositivos considerados y los recursos necesarios para la comunicación con dispositivos móviles de telefonía

Aceptabilidad del ensilaje de la parte aérea de la yuca adicionado con diferentes tipos y cantidades de aditivos en bovinos

The objective of this research was to evaluate the influence of the addition of different types and proportions of byproducts and silage additives to the aerial part of cassava on their acceptability silage at different times, involving the sensory variables, chemical composition and acceptability silage. Experimental design was completely randomized with seven types or proportions of additives and four times silage. Treatments were as a witness, the aerial part of cassava supplemented with 2% molasses, common addition in all treatments; Sil-All® (bacterial inoculant); rice bran (15 and 30% inclusive); ground corn cobs (15 and 30% inclusion) and sugar (3% inclusion). The silages added with tusa were largely accepted by the animals, reflected this in greater number and timing of visits and increased consumption. The silages that included bran were the least accepted. The opening of the silo age did not affect (P>0.05) the study variables. The preference of the animals for the ensiled material compared to silage material not confirmed. The acceptability of the ensiled material was related to some quality variables such as pH, ADF, hemicellulose, fat and DISMS.  l objetivo de esta investigación fue evaluar la influencia de la adición de diferentes tipos y proporciones de subproductos y aditivos al ensilaje de la parte aérea de la yuca sobre su aceptabilidad a diferentes tiempos de ensilado, asociando las variables organolépticas, de composición química y aceptabilidad del ensilaje. Se utilizó un diseño completamente al azar con siete tipos o proporciones de aditivos y cuatro tiempos de ensilado. Los tratamientos fueron: como testigo, la parte aérea de la yuca adicionada con 2% de melaza, adición común en todos los tratamientos; Sil-All® (inoculante bacteriano); salvado de arroz (15 y 30% de inclusión); tusa de maíz molida (15 y 30% de inclusión) y azúcar (3% de inclusión). Los ensilajes adicionados con tusa fueron mayormente aceptados por los animales, reflejado esto en mayor número y tiempo de visitas y un mayor consumo. Los ensilajes que incluyeron salvado fueron los menos aceptados. La edad de abertura del silo no afectó (P>0.05) las variables en estudio. Se confirmó la preferencia de los animales por el material ensilado en comparación al material no ensilado. La aceptabilidad de los materiales ensilados se relacionó con algunas variables de calidad, como pH, FDA, hemicelulosa, grasa y la DISMS