Absolute Radiometric Calibration of TESS-W and SQM Night Sky Brightness Sensors

We develop a general optical model and describe the absolute radiometric calibration of the readings provided by two widely-used night sky brightness sensors based on irradiance-to-frequency conversion. The calibration involves the precise determination of the overall spectral sensitivity of the devices and also the constant G relating the output frequency of the light-to-frequency converter chip to the actual band-weighted and field-of-view averaged spectral radiance incident on the detector (brightness). From these parameters, we show how to define a rigorous astronomical absolute photometric system in which the sensor measurements can be reported in units of magnitudes per square arcsecond with precise physical meaning.S

La perspectiva filosófica de un concepto: una analogía de Bachelard

Es nuestra intención en este trabajo, construir las imágenes analógicas que implícitamente están bocetadas en "La filosofía del no" de Bachelard, tratando de mostrar a un Bachelard analógico al momento de exponer sus ideas, mostrándonos como la ciencia misma ha recurrido a imágenes que al destruirlas condujeron al pensamiento científico a descubrir sus leyes orgánicas. Así vemos como Bachelard si bien marca una ruptura entre las imágenes, metáforas y analogías de la experiencia cotidiana, nos muestra la necesidad de recurrir a ellas por parte de la ciencia, la cuál crea formas realistas y racionales de sus objetos que le otorgan una razón polémica. La historia de la imaginería científica conforma un plan estratégico pedagógico ineluctable para el crecimiento científico (Bachelard, 2003:115)

Determination of genotoxicity of classical swine fever vaccine in vitro by cytogenetic and comet tests

Chromosome damage in lymphocyte cultures induced by live virus vaccine against classical swine fever (CSF) has been observed in previous studies. In vivo cytogenetic tests were made with several doses of vaccines used in Argentina to control the disease. These studies have shown that genotoxic effects increased with dose. In the present study, two different in vitro assays were performed by recording the frequency of cells with chromosome alterations and by assessing the ability of the vaccine to damage DNA, using the single cell gel microelectrophoretic assay (comet test). Frequencies of cells with chromosomal alterations increased significantly when compared with controls and were dose (μl/ml) dependent: 0 = 1.23, 5 = 2.29, 10 = 5.42 and 20 = 11.71%. In the comet assay the variables measured, tail length (TL) and tail moment (TM), also increased. For control cultures TL was 2.32 μm, whereas with concentrations of 20 and 100 μl/ml TL were 12.47 and 42.3 μm, respectively. TM of control cultures was 0.18, whereas with vaccine concentrations of 20 and 100 μl/ml TM were 5.52 and 24.52, respectively. Comet frequency distributions differed significantly among treatments. These results agree with previous in vivo observations. Regarding CSF pathogeny, our results support a direct effect of CSF vaccinal virus on lymphocyte DNA. Genotoxicity of CSF vaccine was corroborated in vitro at the cytogenetic and molecular levels.Instituto de Genética Veterinari

Ventilator-associated Pneumonia After Elective Cardiac Surgery Caused by Pneumocystis Jirovecii

Ventilator-associated pneumonia is a severe complication among patients undergoing cardiac surgery. Although hospital-acquired bacterial pathogens, often multidrug resistant, are the most frequent cause, non-bacterial atypical and opportunistic agents traditionally associated with immunocompromise are increasingly recognized. We describe ventilator-associated pneumonia due to Pneumocystis jirovecii in the absence of traditional risk factors for Pneumocystis pneumonia in a patient after cardiac surgery

Drip loss in different raw meat

Forty samples (average weight of 5.7 g) of Triceps femoral muscle, were taken 24 h post mortem to evaluate the effect of raw meat type (chicken, beef, pig and ostrich) and storage time (24, 48 and 72 h) at 0°C on the drip loss percentage. Data were subjected to ANOVA and Duncan’s test. Variables raw meat type, storage time and their interaction affected (P<0.05) drip loss percentage. The lowest percentage was for ostrich (P<0.05) followed by pig, chicken and beef (1.3 vs 1.7, 2.1 and 2.7%), respectively. Drip loss was 1.2, 1.9 and 2.7% at 24, 48 and 72h respectively. The significant interaction (P<0.05) indicates that the different meat types increased differentially their drip loss with storage time

Desarrollo de un servicio de neurología y psiquiatría en un hospital pediátrico general

Con la presente comunicación nos proponernos mostrar algunas de las características que presenta la asistencia psiquiátrica en un hospital general, a través de la evolución y funcionamiento actual del Servicio de Neurología y Psiquiatría del Hospital de Niños de La Plata. En este hospital funcionaron esporádicamente consultorios de la especialidad, pero recién en julio de 1957 se contó con un Consultorio Externo estable. En febrero de 1962 se constituyó como Servicio de Neurología y Psiquiatría, incorporándose las salas de internación, que fueron inauguradas en abril de 1964. (Párrafo extraído del texto a modo de resumen)Departamento de Psicologí

Glicerólisis de oleínas de cacao con lipasa Candida antarctica en un sistema libre de solventes

In this paper we present the valorization of cocoa olein obtained from the acid fat-splitting of soapstocks. The aim is to develop a solvent free process (enzymatically catalyzed) to maximize the production of a final product with high content of monoglycerides (MAG) and diglycerides (DAG). The effect of the enzyme dose, glycerol content, reaction times as well as the modification of the raw material and pressure were studied. The yield of the reaction increased up to 90-95% when using a vacuum of 2-3 mbar at 65 °C, enough to evaporate the water which is generated as a by-product, an enzyme dose of 1% and molar ratio oil:glycerol of 1:2. The highest yield in terms of MAG and DAG production was obtained by starting from a raw material which was rich in free acidity (FFA), rendering oil with 33.4 and 44.2% MAG and DAG, respectively. Short reaction times (6-8 h) were observed compared to previously reported results (24 h).En el presente trabajo se pretende valorizar la oleína vegetal de cacao procedente de la ruptura ácida de las pastas de refinación química. El objetivo es poner a punto un proceso de glicerólisis enzimática en un sistema libre de solventes maximizando la producción de monoglicéridos (MAG) y diglicéridos (DAG). Se ha estudiado el efecto de la dosis de enzima, el contenido de glicerol y el tiempo de reacción, la modificación de la presión de reacción y la composición de la materia prima. Se concluye que el rendimiento de la reacción aumenta hasta el 90-95% cuando se aplica un vacío de 2-3 mbar a 65 ºC suficiente para evaporar el agua que se va generando como producto, una dosis de enzima del 1% y una relación molar aceite:glicerol 1:2. El mayor rendimiento en cuanto a la producción de MAG y DAG se ha conseguido partiendo de una materia prima rica en acidez libre (FFA), obteniéndose un aceite con un 33.4 y 44.2% de MAG y DAG, respectivamente. Se observa que los tiempos de reacción son cortos (6-8h) comparados con los descritos en la bibliografía encontrada (24h)