211 research outputs found
Qubits and chirotopes
We show that qubit and chirotope concepts are closely related. In fact, we
prove that the qubit concept leads to a generalization of the chirotope
concept, which we call qubitope. Moreover, we argue that a possible qubitope
theory may suggest interesting applications of oriented matroid theory in at
least three physical contexts, in which qubits make their appearance, namely
string theory, black holes and quantum information.Comment: 11 pages, Late
Uso de nanodiscos de anfotericina B (AMB-NDs) para el tratamiento de enfermedades fúngicas en plantas
III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce
Plasma and cerebrospinal fluid concentrations of linezolid in neurosurgical critically ill patients with proven or suspected central nervous system infections
Linezolid is a valuable treatment option for central nervous system (CNS) infections caused by multidrug-resistant Gram-positive micro-organisms. Data regarding its penetration into the CNS have shown wide variability. The aim of this study was to describe the population pharmacokinetics of linezolid in plasma and cerebrospinal fluid (CSF) in critically ill patients with external CSF drainage and proven or suspected CNS infections. This was an observational pharmacokinetic (PK) study in 11 critically ill patients with proven or suspected CNS infection receiving linezolid. Serial blood and CSF samples were taken and were subject to population PK analysis. The median (interquartile range) of AUC(0-12h) was 47.6 (17.9-58.6) mg h/L in plasma and 21.1(18.8-30.4) mg h/L in CSF, with a median CSF/plasma ratio of 0.77. At pre-dose at steady state, a strong positive correlation was observed between linezolid concentrations in CSF and plasma (Spearman's rho = 0.758; P = 0.011). For a minimum inhibitory concentration (MIC) of 2 mg/L, the median AUC(0-24h)/MIC values in plasma and CSF wer
Productive and sanitary characterization of suckling calves breeding in Córdoba and Santa Fé (Argentina)
A study has been made in 72 dairy farms in the Argentine provinces of Cordoba and Santa Fe between years 2000 and 2002. This article is mainly referring to the calves in suckling stage, before its transfer to the pasture. The objective was to make a valuation of the main charac-teristics of farms and the breeding system of dairy calves in the zone. A questionnaire was designed, structuring the questions in six different sections: questions of general type, workers, feeding, handling, other species and contagious, and biosecurity and health. Among the results, it emphasizes the big size of farms, the great diffusion of open systems and the little pursuit of biosecurity measures.Se ha realizado un estudio, entre los años 2000 y 2002, en 72 explotaciones bovinas de aptitud láctea situadas en las provincias argentinas de Córdoba y Santa Fé. El estudio se centró principalmente en las primeras fases de producción de terneros, previamente a su traslado a los pastos. El objetivo fue realizar una valoración de las principales características de las explotaciones y el sistema de cría de terneros en la zona. Para ello, se diseñó un cuestionario, estructu-rándose las preguntas en seis apartados: cuestiones de tipo general, personal, alimentación, prácticas de manejo, otras especies y contagio y, bioseguridad y sanidad. Entre los resultados, destaca el gran tamaño de las explotaciones, la amplia difusión de sistemas abiertos y el escaso seguimiento de medidas de bioseguridad
Los indicadores de gestión y las técnicas de benchmarking aplicados a la mejora de las comunidades de regantes
[ES] Benchmarking es una técnica para lograr mejoras en organizaciones, realizando comparaciones y adaptando las prácticas que han llevado a otras a ser consideradas como las mejores. En este trabajo se realiza una aplicación de dichas técnicas al análisis y la mejora de nueve Comunidades de Regantes de Andalucía, cubriéndose una superficie total de más de 71000 ha. Para detectar las diferencias se han empleado dos conjuntos de indicadores de gestión: uno general desarrollado por IPTRID y otro desarrollado para este trabajo, consistente en una ampliación de indicadores financieros. La comparación de los indicadores permite obtener diversas conclusiones sobre cuáles son las prácticas más deseables existentes en los regadíos y conocer qué Comunidades de Regantes son las más eficientes en el empleo de los recursos. Por último, las Comunidades de Regantes analizadas se clasifican mediante técnicas de análisis de cluster. Este tipo de análisis ha permitido agrupar las nueve Comunidades de Regantes en cuatro grupos estadísticamente homogéneos, lo que facilita las comparaciones entre las mismas, estableciendo los puntos fuertes y débiles de cada uno de los tipos de regadíos existentes en Andalucía.Rodríguez Díaz, J.; Camacho Poyato, E.; López Luque, R.; Pérez Urrestarazu, L. (2005). Los indicadores de gestión y las técnicas de benchmarking aplicados a la mejora de las comunidades de regantes. Ingeniería del agua. 12(1):63-76. https://doi.org/10.4995/ia.2005.2552OJS6376121Cabrera Jr., E. (2001). Diseño de un sistema para la evaluación de la gestión de abastecimientos urbanos. Tesis doctoral. Universidad Politécnica de Valencia.Consejería de Agricultura y Pesca. (2003). www.cap.junta-andalucia.es. Junta de Andalucía.Carrasco, J.L. y M.A. Hernán. (1993). Estadística Multivariante en las Ciencias de la Vida. Editorial Ciencia 3. Madrid.Davis, J.C. (1973). Statistics and Data Analysis in Geology Editorial John Willey & Sons.International Water Management Institute. (2004). www.iwmi.orgJain, A. K. (2000). Statistical Pattern Recognition: A Review. IEEE Transactions on Pattern Analysis and Machine Intelligence. 22: 4 -38Levine, G. (1982). Relative Water Supply: An explanatory variable for irrigation systems. Technichal Report No. 6. Cornell University. Ithaca, New York. EEUU.Malano, H. y M. Burton. (2001). Guidelines for benchmarking performance in the irrigation and drainage sector. International Programme for Technology and Research in Irrigation and Drainage.Maravall, D. 1993. Reconocimiento de Formas y Visión Artificial. Editorial RAMA. Madrid.Pavón, R.; Camacho, E. y M.J. Polo. (2004). Estudio de los indicadores ambientales y de comportamiento del riego en la zona regable del Bembézar Margen Izquierda. XXII Congreso Nacional de Riegos. Logroño.Pérez, L.; Rodríguez, J. A.; Camacho, E.; López, R.; Roldán, J.; Alcaide, M.; Ortiz, J.A.; Segura, R. (2003b). IGRA. An Approach for the application of the benchmarking initiative to irrigation areas. ICID-CIID. 54th International Executive Council. 20th European Regional Conference. Montpellier (Francia).Pérez, L.; Rodríguez, J.A.; López, R.; Camacho, E. (2003a). IGRA.Aplicación informática para el cálculo y comparación de los Indicadores de Gestión de Zonas Regables.XXI Congreso Nacional de Riegos. Mérida.Rao, P.S. (1993). Review of selected literature on indicators of irrigation performance. IIMI Research paper No. 13. International Irrigation Management Institute. Colombo. Sri Lanka.Rodríguez, J. A. (2004). Estudio de la gestión del agua de riego y aplicación de las técnicas de benchmarking a las zonas regables de Andalucía. Tesis Doctoral. Universidad de Córdoba.Rodríguez, J.A.; Camacho, E. y R. López. (2004a). Applying Benchmarking and Data Envelopment Analysis (DEA) to Irrigation Districts in Spain. Irrigation and Drainage. 53: 1-10.Rodríguez, J.A.; Camacho, E.; R. López y L. Pérez. (2004b). Indicadores de gestión: una herramienta para el análisis de las Comunidades de Regantes. XXII Congreso Nacional de Riegos. Logroño
Synthesis and Antiproliferative Activity of Sulfa-Michael Adducts and Thiochromenes Derived from Carbohydrates
The Michael addition reactions of carbohydrate-derived nitroalkenes with ethyl thioglycolate and 2-mercaptobenzyl alcohol were studied. Reactions were conducted under mild, solvent-free conditions with DABCO as a catalyst, affording the corresponding adducts in good yields. Furthermore, compounds resulting from the addition with 2-mercaptobenzyl alcohol were used as starting materials for the synthesis of chiral 3-nitro-2H-thiochromenes. For some of the compounds synthesized herein, the antioxidant and antiproliferative activities against a panel of human solid tumor cell lines were assayed and compared with those of carbohydrate-nitroalkene substrates.Junta de Extremadura GR15022Unión Europea FP7-REGPOT-2012-CT2012-31637-IMBRAI
Multi-variate model of T cell clonotype competition and homeostasis
Diversity of the naive T cell repertoire is maintained by competition for stimuli provided by self-peptides bound to major histocompatibility complexes (self-pMHCs). We extend an existing bi-variate competition model to a multi-variate model of the dynamics of multiple T cell clonotypes which share stimuli. In order to understand the late-time behaviour of the system, we analyse: (i) the dynamics until the extinction of the first clonotype, (ii) the time to the first extinction event, (iii) the probability of extinction of each clonotype, and (iv) the size of the surviving clonotypes when the first extinction event takes place. We also find the probability distribution of the number of cell divisions per clonotype before its extinction. The mean size of a new clonotype at quasi-steady state is an increasing function of the stimulus available to it, and a decreasing function of the fraction of stimuli it shares with other clonotypes. Thus, the probability of, and time to, extinction of a new clonotype entering the pool of T cell clonotypes is determined by the extent of competition for stimuli it experiences and by its initial number of cells
Space-filling and benthic competition on coral reefs
Reef-building corals are ecosystem engineers that compete with other benthic organisms for space and resources. Corals harvest energy through their surface by photosynthesis and heterotrophic feeding, and they divert part of this energy to defend their outer colony perimeter against competitors. Here, we hypothesized that corals with a larger space-filling surface and smaller perimeters increase energy gain while reducing the exposure to competitors. This predicted an association between these two geometric properties of corals and the competitive outcome against other benthic organisms. To test the prediction, fifty coral colonies from the Caribbean island of Curaçao were rendered using digital 3D and 2D reconstructions. The surface areas, perimeters, box-counting dimensions (as a proxy of surface and perimeter space-filling), and other geometric properties were extracted and analyzed with respect to the percentage of the perimeter losing or winning against competitors based on the coral tissue apparent growth or damage. The increase in surface space-filling dimension was the only significant single indicator of coral winning outcomes, but the combination of surface space-filling dimension with perimeter length increased the statistical prediction of coral competition outcomes. Corals with larger surface space-filling dimensions (Ds > 2) and smaller perimeters displayed more winning outcomes, confirming the initial hypothesis. We propose that the space-filling property of coral surfaces complemented with other proxies of coral competitiveness, such as life history traits, will provide a more accurate quantitative characterization of coral competition outcomes on coral reefs. This framework also applies to other organisms or ecological systems that rely on complex surfaces to obtain energy for competition
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