1,246 research outputs found
Survival of thermophilic spore-forming bacteria in a 90+ year old milk powder from Ernest Shackelton's Cape Royds Hut in Antarctica
Milk powder taken to Antarctica on Shackelton's British Antarctic Expedition in 1907 was produced in New Zealand by a roller drying process in the first factory in the world dedicated to this process. Thermophilic bacilli are the dominant contaminants of modern spray-dried milk powders and the 1907 milk powder allows a comparison to be made of contaminating strains in roller-dried and spray-dried powders. Samples of milk powder obtained from Shackelton's Hut at Cape Royds had low levels of thermophilic contamination (<500 cfu ml−1) but the two dominant strains (Bacillus licheniformis strain F and Bacillus subtilis) were typical of those found in spray-dried powders. Soil samples from the floor of the hut also contained these strains, whereas soils distant from the hut did not. Differences in the RAPD profiles of isolates from the milk powder and the soils suggest that contamination of the milk from the soil was unlikely. It is significant that the most commonly encountered contaminant strain in modern spray-dried milk (Anoxybacillus flavithermus strain C) was not detected in the 1907 sample
A comprehensive investigation of the mineral composition of brazilian bee pollen: geographic and seasonal variations and contribution to human diet
The mineral composition of bee pollen was investigated in 154 samples from different Brazilian regions. Ca, Cu, Fe, K, Mg, Mn, Na, P, Se and Zn were determined by ICP OES after microwave mineralization. Employing optimized instrumental parameters, the method was shown to have a good precision and accuracy for the simultaneous determination of minerals. Overall, samples from the Northeastern states presented significantly higher amounts of minerals and showed constant production throughout the year. Manganese, Se, Cu, Zn and Fe were the elements that showed the greatest possible contributions to the diet, contributing with 70, 37, 27, 17 and 17%, respectively, of the Brazilian recommended daily intake. Principal component analysis (PCA) was applied to study geographic effects. The elements Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn were important in explaining the classification of pollen according to their geographical origin. The mineral levels varied widely during the year.A composição de minerais foi investigada em 154 amostras de pólen apícola, provenientes de diferentes regiões do Brasil. A técnica de ICP OES foi utilizada para determinar Ca, Cu, Fe, K, Mg, Mn, Na, P, Se e Zn, após mineralização em sistema de microondas. Utilizando parâmetros instrumentais otimizados conseguiu-se boa exatidão e precisão na determinação simultânea dos minerais. Em geral, as amostras dos estados do Nordeste apresentaram teores de minerais mais elevados e produção constante durante o ano. Os minerais Mn, Se, Cu, Zn, Fe são os que poderiam ter maior contribuição na dieta, podendo atingir 70, 37, 27, 17 e 17%, respectivamente, da ingestão dietética diária recomendada no Brasil. A análise de componentes principais mostrou que Ca, Cu, Fe, K, Mg, Mn, Na, P e Zn podem ser usados na classificação do pólen nacional em função da origem geográfica. Os teores dos minerais variaram amplamente ao longo do ano.727736Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
La cerámica arqueológica inka de Humahuaca, Iruya, Aullagas, Talina y Suipacha (Argentina-Bolivia): Un examen petrográfico comparado
Se realiza un estudio mineralógico comparado de las fracciones arcilla y arena de cerámicas que presentan estilos culturales (basados en la forma y la decoración) diferentes, con edades aproximadas de 1500 d.c , provenientes del Noroeste de Argentina y del centro-sur de Bolivia. Los resultados muestran que el ámbito geológico local ejerce un importante control sobre la composición de las mismas y aún para un mismo estilo extendido como el Inka, la gran variación composicional y regional sugiere la copia de modelos exportados desde otras regiones del Imperio Incaico, utilizando sedimentos locales como materia prima. Con estos datos se infieren además procedencias a partir de terrenos graníticos y volcánicos para cada yacimiento arqueológico
Investigación en metodologías de aprendizaje para grupos ARA en la materia de arquitectura de computadores
La enseñanza en inglés es uno de los retos a los que se está enfrentando actualmente la universidad española. La Universidad de Alicante ofrece a través de los grupos de Alto Rendimiento Académico (ARA) parte de la docencia de los estudios de grado en inglés. El objetivo principal de esta red es la de consolidar y ampliar la investigación realizada en metodologías de aprendizaje para grupos ARA en la materia de arquitectura de computadores. En consecuencia, se pretende ampliar los materiales docentes en inglés en relación con la enseñanza de asignaturas relacionadas con la materia en estos grupos de alto rendimiento. Estas asignaturas son impartidas por varios miembros de la red en diferentes cursos de los Grados de Ingeniería Informática y de Ingeniería en Sonido e Imagen en Telecomunicación. Como caso práctico, se ha continuado con la investigación en la asignatura Arquitectura de Computadores del Grado de Ingeniería Informática. Para ello, se han elaborado nuevos materiales para prácticas que permiten la participación activa y el trabajo en equipo. Cada uno de los materiales propuestos está diseñado dentro del marco metodológico implementado en la asignatura, relacionado con la consecución de objetivos y competencias, y con la evaluación de la misma
Acinetobacter baumannii response to cefiderocol challenge in human urine
Cefiderocol (CFDC) is a novel chlorocatechol-substituted siderophore antibiotic approved to treatcomplicated urinary tract infections (cUTI) and hospital-acquired and ventilator-acquired pneumonia(HAP/VAP). Previous work determined that albumin-rich human fluids increase the minimuminhibitory concentration (MICs) of Acinetobacter baumannii against CFDC and reduce the expressionof genes related to iron uptake systems. This latter effect may contribute to the need for higherconcentrations of CFDC to inhibit growth. The presence of human urine (HU), which contains lowalbumin concentrations, did not modify MIC values of two carbapenem-resistant A. baumannii. Levelsof resistance to CFDC were not modified by HU in strain AMA40 but were reduced in strain AB5075.Expanding the studies to other carbapenem-resistant A. baumannii isolates showed that the presenceof HU resulted in unmodified or reduced MIC of CDFC values. The expression of piuA, pirA, bauA,and bfnH determined by qRT-PCR was enhanced in A. baumannii AMA40 and AB5075 by the presenceof HU in the culture medium. All four tested genes code for functions related to recognition andtransport of ferric-siderophore complexes. The effect of HU on expression of pbp1, pbp3, blaOXA-51-like, blaADC, and blaNDM-1, genes associated with resistance to β-lactams, as well as genes coding for efflux pumps and porins was variable, showing dependence with the strain analyzed. We conclude that the lack of significant concentrations of albumin and free iron in HU makes this fluid behave differently from others we tested. Unlike other albumin rich fluids, the presence of HU does not impact the antibacterial activity of CFDC when tested against A. baumannii.Fil: Nishimura, Brent. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Escalante, Jenny. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Tuttobene, Marisel Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Centro de Estudios Fotosintéticos y Bioquímicos. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Centro de Estudios Fotosintéticos y Bioquímicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Subils, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; ArgentinaFil: Mezcord, Vyanka. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Pimentel, Camila. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Georgeos, Nardin. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Pasteran, Fernando. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Rodriguez, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Sieira, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Actis, Luis A.. Miami University; Estados UnidosFil: Tolmasky, Marcelo E.. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Bonomo, Robert A.. Center for Antimicrobial Resistance and Epidemiology; Estados Unidos. Case Western Reserve University; Estados UnidosFil: Ramirez, Maria Soledad. California State University. College Of Natural Science And Mathematics; Estados Unido
GW150914: First search for the electromagnetic counterpart of a gravitational-wave event by the TOROS collaboration
We present the results of the optical follow-up conducted by the TOROS
collaboration of the first gravitational-wave event GW150914. We conducted
unfiltered CCD observations (0.35-1 micron) with the 1.5-m telescope at Bosque
Alegre starting ~2.5 days after the alarm. Given our limited field of view
(~100 square arcmin), we targeted 14 nearby galaxies that were observable from
the site and were located within the area of higher localization probability.
We analyzed the observations using two independent implementations of
difference-imaging algorithms, followed by a Random-Forest-based algorithm to
discriminate between real and bogus transients. We did not find any bona fide
transient event in the surveyed area down to a 5-sigma limiting magnitude of
r=21.7 mag (AB). Our result is consistent with the LIGO detection of a binary
black hole merger, for which no electromagnetic counterparts are expected, and
with the expected rates of other astrophysical transients.Comment: ApJ Letters, in pres
La Web Semántica Como Herramienta para el Apoyo a la Docencia
La web semántica consiste en un nuevo paradigma web para acceder, buscar, compartir y gestionar información a través de la combinación de tecnologías y de estructuras de gestión del conocimiento. El concepto de web semántica proporciona herramientas para el almacenamiento, intercambio y consulta de esta información mediante el desarrollo y la inclusión de metadatos y ontologías del cuerpo de conocimiento. La estructura de los datos que proporciona permite que sea consultada automáticamente por usuarios humanos o sistemas informáticos, mejorando su interoperabilidad. El desarrollo de la web semántica supone una evolución del desarrollo web en general hacia una web más inteligente o web 3.0. Este paradigma puede ser aprovechado en los procesos de docencia-aprendizaje para estructurar, almacenar y compartir los contenidos mediante sistemas automáticos de consultas alojados en web semánticas que tratan sobre los cuerpos de conocimiento de las materias. La disciplina informática es especialmente adecuada para este propósito debido a su complejidad y a la gran variedad de términos que maneja. Por otra parte, su desarrollo en continua evolución propicia la implantación de mecanismos automáticos de mantenimiento y de actualización de los nuevos contenidos
Severe Diarrhea in the Setting of Immune Checkpoint Inhibitors
Immune checkpoint inhibitors (ICPIs) are novel therapeutic agents targeting a variety of cancers by enhanced T cell activation. Immune-related adverse events (irAEs) commonly occur with ICPI use and can affect multiple organ systems including the gastrointestinal tract. Due to irAEs, the use of ICPIs is limited in autoimmune diseases. We present a case of microscopic colitis diagnosed after the initiation of nivolumab and a case of ipilimumab colitis and Clostridium difficile in the setting of Crohn’s colitis
Time and frequency pump-probe multiplexing to enhance the signal response of Brillouin optical time-domain analyzers
© 2014 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibitedA technique to enhance the response and performance of Brillouin distributed fiber sensors is proposed and experimentally validated. The method consists in creating a multi-frequency pump pulse interacting
with a matching multi-frequency continuous-wave probe. To avoid nonlinear cross-interaction between spectral lines, the method requires that the distinct pump pulse components and temporal traces reaching the photodetector are subject to wavelength-selective delaying. This way the total pump and probe powers launched into the fiber can be incrementally boosted beyond the thresholds imposed by nonlinear effects. As a consequence of the multiplied pump-probe Brillouin interactions occurring along the fiber, the sensor response can be enhanced in exact proportion to the number of spectral components. The method is experimentally validated in a 50 km-long distributed optical fiber sensor augmented to 3 pump-probe spectral pairs, demonstrating a signal-to-noise ratio enhancement of 4.8 dB.The authors would like to thank Mr. Javier Urricelqui from Universidad Publica de Navarra (Spain) for the valuable discussions and help in relation to the noise characteristics of BOTDA sensors. This work was performed in the framework and with the support of the COST Action TD1001 OFSeSa. M. A. Soto and L. Thevenaz acknowledge the support from the Swiss Commission for Technology and Innovation (Project 13122.1), and from the Swiss State Secretariat for Education, Research and Innovation (SERI) through the project COST C10.0093. UPVLC group acknowledges the support from the Spanish MICINN and the Valencia Government through the projects TEC2011-29120-C05-05 and ACOMP/2013/146, respectively. L. Zhang acknowledges the support from the China Scholarship Council during his stay at EPFL in Switzerland.Soto, MA.; Ricchiuti, AL.; Zhang, L.; Barrera Vilar, D.; Sales Maicas, S.; Thevenaz, L. (2014). Time and frequency pump-probe multiplexing to enhance the signal response of Brillouin optical time-domain analyzers. Optics Express. 22(23):28584-28595. https://doi.org/10.1364/OE.22.028584S28584285952223Horiguchi, T., Shimizu, K., Kurashima, T., Tateda, M., & Koyamada, Y. (1995). Development of a distributed sensing technique using Brillouin scattering. Journal of Lightwave Technology, 13(7), 1296-1302. doi:10.1109/50.400684Soto, M. A., & Thévenaz, L. (2013). Modeling and evaluating the performance of Brillouin distributed optical fiber sensors. Optics Express, 21(25), 31347. doi:10.1364/oe.21.031347Foaleng, S. M., & Thévenaz, L. (2011). Impact of Raman scattering and modulation instability on the performances of Brillouin sensors. 21st International Conference on Optical Fiber Sensors. doi:10.1117/12.885105Alem, M., Soto, M. A., & Thévenaz, L. (2014). Modelling the depletion length induced by modulation instability in distributed optical fibre sensors. 23rd International Conference on Optical Fibre Sensors. doi:10.1117/12.2058862Thévenaz, L., Mafang, S. F., & Lin, J. (2013). Effect of pulse depletion in a Brillouin optical time-domain analysis system. Optics Express, 21(12), 14017. doi:10.1364/oe.21.014017Minardo, A., Bernini, R., & Zeni, L. (2009). A Simple Technique for Reducing Pump Depletion in Long-Range Distributed Brillouin Fiber Sensors. IEEE Sensors Journal, 9(6), 633-634. doi:10.1109/jsen.2009.2019372Soto, M. A., Bolognini, G., Di Pasquale, F., & Thévenaz, L. (2010). Simplex-coded BOTDA fiber sensor with 1 m spatial resolution over a 50 km range. Optics Letters, 35(2), 259. doi:10.1364/ol.35.000259Soto, M. A., Bolognini, G., & Di Pasquale, F. (2010). Analysis of pulse modulation format in coded BOTDA sensors. Optics Express, 18(14), 14878. doi:10.1364/oe.18.014878Rodriguez-Barrios, F., Martin-Lopez, S., Carrasco-Sanz, A., Corredera, P., Ania-Castanon, J. D., Thevenaz, L., & Gonzalez-Herraez, M. (2010). Distributed Brillouin Fiber Sensor Assisted by First-Order Raman Amplification. Journal of Lightwave Technology, 28(15), 2162-2172. doi:10.1109/jlt.2010.2051141Martin-Lopez, S., Alcon-Camas, M., Rodriguez, F., Corredera, P., Ania-Castañon, J. D., Thévenaz, L., & Gonzalez-Herraez, M. (2010). Brillouin optical time-domain analysis assisted by second-order Raman amplification. Optics Express, 18(18), 18769. doi:10.1364/oe.18.018769Soto, M. A., Bolognini, G., & Di Pasquale, F. (2011). Optimization of long-range BOTDA sensors with high resolution using first-order bi-directional Raman amplification. Optics Express, 19(5), 4444. doi:10.1364/oe.19.004444Soto, M. A., Taki, M., Bolognini, G., & Pasquale, F. D. (2012). Simplex-Coded BOTDA Sensor Over 120-km SMF With 1-m Spatial Resolution Assisted by Optimized Bidirectional Raman Amplification. IEEE Photonics Technology Letters, 24(20), 1823-1826. doi:10.1109/lpt.2012.2212183Jia, X.-H., Rao, Y.-J., Yuan, C.-X., Li, J., Yan, X.-D., Wang, Z.-N., … Peng, F. (2013). Hybrid distributed Raman amplification combining random fiber laser based 2nd-order and low-noise LD based 1st-order pumping. Optics Express, 21(21), 24611. doi:10.1364/oe.21.024611Soto, M. A., Angulo-Vinuesa, X., Martin-Lopez, S., Chin, S.-H., Ania-Castanon, J. D., Corredera, P., … Thevenaz, L. (2014). Extending the Real Remoteness of Long-Range Brillouin Optical Time-Domain Fiber Analyzers. Journal of Lightwave Technology, 32(1), 152-162. doi:10.1109/jlt.2013.2292329Soto, M. A., Bolognini, G., & Pasquale, F. D. (2009). Distributed optical fibre sensors based on spontaneous Brillouin scattering employing multimode Fabry-Pérot lasers. Electronics Letters, 45(21), 1071. doi:10.1049/el.2009.2381Li, C., Wang, F., Lu, Y., & Zhang, X. (2012). SNR enhancement in Brillouin optical time domain reflectometer using multi-wavelength coherent detection. Electronics Letters, 48(18), 1139-1141. doi:10.1049/el.2012.1248Voskoboinik, A., Wang, J., Shamee, B., Nuccio, S. R., Zhang, L., Chitgarha, M., … Tur, M. (2011). SBS-Based Fiber Optical Sensing Using Frequency-Domain Simultaneous Tone Interrogation. Journal of Lightwave Technology, 29(11), 1729-1735. doi:10.1109/jlt.2011.2145411Voskoboinik, A., Yilmaz, O. F., Willner, A. W., & Tur, M. (2011). Sweep-free distributed Brillouin time-domain analyzer (SF-BOTDA). Optics Express, 19(26), B842. doi:10.1364/oe.19.00b842Chaube, P., Colpitts, B. G., Jagannathan, D., & Brown, A. W. (2008). Distributed Fiber-Optic Sensor for Dynamic Strain Measurement. IEEE Sensors Journal, 8(7), 1067-1072. doi:10.1109/jsen.2008.926107Nikles, M., Thevenaz, L., & Robert, P. A. (1997). Brillouin gain spectrum characterization in single-mode optical fibers. Journal of Lightwave Technology, 15(10), 1842-1851. doi:10.1109/50.633570Jacobs, I. (1995). Dependence of optical amplifier noise figure on relative-intensity-noise. Journal of Lightwave Technology, 13(7), 1461-1465. doi:10.1109/50.400712Bolognini, G., Soto, M. A., & Di Pasquale, F. (2009). Fiber-Optic Distributed Sensor Based on Hybrid Raman and Brillouin Scattering Employing Multiwavelength Fabry–PÉrot Lasers. IEEE Photonics Technology Letters, 21(20), 1523-1525. doi:10.1109/lpt.2009.202889
A comprehensive investigation of the mineral composition of brazilian bee pollen: geographic and seasonal variations and contribution to human diet
The mineral composition of bee pollen was investigated in 154 samples from different Brazilian regions. Ca, Cu, Fe, K, Mg, Mn, Na, P, Se and Zn were determined by ICP OES after microwave mineralization. Employing optimized instrumental parameters, the method was shown to have a good precision and accuracy for the simultaneous determination of minerals. Overall, samples from the Northeastern states presented significantly higher amounts of minerals and showed constant production throughout the year. Manganese, Se, Cu, Zn and Fe were the elements that showed the greatest possible contributions to the diet, contributing with 70, 37, 27, 17 and 17%, respectively, of the Brazilian recommended daily intake. Principal component analysis (PCA) was applied to study geographic effects. The elements Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn were important in explaining the classification of pollen according to their geographical origin. The mineral levels varied widely during the year
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