58 research outputs found
Effect of nanostructured WO3 layers in the sensitivity to nitrogen oxide in YSZ-based electrochemical sensors for automotive applications
AbstractThe sensitivity to nitrogen monoxide (NO) is studied and compared when using several YSZ-based electrochemical gas sensors with identical characteristics but covered by different porous layers over one of their catalytic Pt electrodes. Sensors are exposed to several exhaust gas mixtures containing nitrogen monoxide. The gases are composed by a low concentration of NO dissolved in N2 atmosphere or by a low concentration of NO dissolved in a multi-component mixture similar to exhaust gases from internal combustion engines. The optimum layer thickness and preparation temperture to enhance NO sensitivity are studied. Regarding the composition of the layers, layers made of nanostructured WO3 mixed with porous YSZ seem to maximize the NO sensitivity and decrease crossed sensitivities
Cambiando de perspectiva: Naturaleza de la ciencia y observación
Trabajar con los estudiantes siguiendo una rutina monótona puede suponer un descenso de la motivación que sienten hacia la materia. Plantear actividades en las que incluyan diferentes perspectivas puede resultarnos útil para salir esta situación. Trabajar enfoques CTS, perspectiva de género y trabajos multidisciplinares ayudarán a los estudiantes a mejorar sus competencias básicas y, por otro lado, los docentes tendremos la posibilidad de observar sus reacciones para mejorar nuestra actuación docente
Solving the random Legendre differential equation: Mean square power series solution and its statistical functions
In this paper we construct, by means of random power series, the solution of second order linear differential equations of Legendre-type containing uncertainty through its coefficients and initial conditions. By assuming appropriate hypotheses on the data, we prove that the constructed random power series solution is mean square convergent. In addition, the main statistical functions of the approximate solution stochastic process generated by truncation of the exact power series solution are given. Finally, we apply the proposed method to some illustrative examples to compare the numerical results for the average and the variance with respect to those obtained by the Monte Carlo approach. © 2011 Elsevier Ltd. All rights reserved.This work has been partially supported by the Spanish M.C.Y.T. grants MTM2009-08587, DPI2010-20891-C02-01, Universidad Politecnica de Valencia grant PAID06-09-2588 and Mexican Conacyt.Calbo Sanjuán, G.; Cortés López, JC.; Jódar Sánchez, LA.; Villafuerte Altuzar, L. (2011). Solving the random Legendre differential equation: Mean square power series solution and its statistical functions. Computers and Mathematics with Applications. 61(9):2782-2792. https://doi.org/10.1016/j.camwa.2011.03.045S2782279261
Laparoscopic and robot-assisted laparoscopic digestive surgery: Present and future directions
Laparoscopic surgery is applied today worldwide to most digestive procedures. In some of them, such as cholecystectomy, Nissen’s fundoplication or obesity surgery, laparoscopy has become the standard in practice. In others, such as colon or gastric resection, the laparoscopic approach is frequently used and its usefulness is unquestionable. More complex procedures, such as esophageal, liver or pancreatic resections are, however, more infrequently performed, due to the high grade of skill necessary. As a result, there is less clinical evidence to support its implementation. In the recent years, robot-assisted laparoscopic surgery has been increasingly applied, again with little evidence for comparison with the conventional laparoscopic approach. This review will focus on the complex digestive procedures as well as those whose use in standard practice could be more controversial. Also novel robot-assisted procedures will be updated
Distribuciones de probabilidad continuas y ecuaciones diferenciales ordinarias
[ES] En este trabajo se presenta una sencilla metodología para
introducir algunas funciones de distribución de probabilidad
de variables aleatorias continuas estándar como soluciones de
ecuaciones diferenciales ordinarias. Este enfoque permite conectar
a nivel docente la enseñanza de áreas como el Cálculo y la Estadística.[EN] This paper proposes a simple methodology to introduce some probability
distribution functions associated to standard continuous random
variables as the solution of ordinary differential equations.
Both Statistics and Calculus teaching can be beneficed from
the proposed approach.Cortés López, JC.; Navarro Quiles, A.; Sánchez Sánchez, A.; Calbo Sanjuán, G. (2016). Distribuciones de probabilidad continuas y ecuaciones diferenciales ordinarias. Boletín de la Sociedad Puig Adam de Profesores de Matemáticas. 101:42-49. http://hdl.handle.net/10251/79236S424910
Estrategias en internet a partir de un modelo de dinámica competitiva
The present paper studies the characteristics and strategies suggested by a model of web sites competition dynamics, based on the Lotka-Volterra competition equations. The model captures the well know winner-take-all characteristic that is caused by the strong positive feedback mechanisms linked to high competence. From the analysis, both quantitative and qualitatively, of the model a series of strategic recommendations are offered to reach success, that prove to be coherent with the trends observed in the Internet real market. Among the above mentioned recommendations, the strategy of coopetition is highlighted as the most suitable option for small sites in order to deal with the leaders of the Net, being this one of the most interesting and novel behaviors that arise from the above mentioned analysis. This alternative strategy to the competition is backed by the predictions offered by a model of competitive dynamics. Furthermore, a series of interesting strategies for start-ups sites or new comers to the market are suggested, like segmentation and affiliation programs between vertical portals.En el presente trabajo se estudia un modelo que describe las principales características del mercado de Internet y las dinámicas competitivas de los denominados sitios web. Este modelo, basado en las ecuaciones de Lotka-Volterra, analiza situaciones del tipo ‘el ganador se lleva todo’ manifestadas recurrentemente en mercados altamente competitivos. Con base en su tratamiento tanto cuantitativo como cualitativo se ofrecen una serie de recomendaciones estratégicas para mejorar resultados, por supuesto, coherentes con las tendencias observadas en la realidad de la Red. Dentro de estas recomendaciones destaca la estrategia de competición, que se propone como una opción viable para que los sitios pequeños puedan hacer frente a los grandes líderes de Internet; reforzada por su fundamento en consonancia con las predicciones propias de un modelo de dinámica competitiva. Junto a ello, también se formulan diversas estrategias para los sitios de nueva creación o recién llegados al mercado (los conocidos start-ups) como la de segmentación y los programas de filiación entre portales verticales
Time dependent expression of the blood biomarkers EIF2D and TOX in patients with schizophrenia
Background
During last years, there has been an intensive search for blood biomarkers in schizophrenia to assist in diagnosis, prognosis and clinical management of the disease.
Methods
In this study, we first conducted a weighted gene coexpression network analysis to address differentially expressed genes in peripheral blood from patients with chronic schizophrenia (n?=?30) and healthy controls (n?=?15). The discriminating performance of the candidate genes was further tested in an independent cohort of patients with first-episode schizophrenia (n?=?124) and healthy controls (n?=?54), and in postmortem brain samples (cingulate and prefrontal cortices) from patients with schizophrenia (n?=?34) and healthy controls (n?=?35).
Results
The expression of the Eukaryotic Translation Initiation Factor 2D (EIF2D) gene, which is involved in protein synthesis regulation, was increased in the chronic patients of schizophrenia. On the contrary, the expression of the Thymocyte Selection-Associated High Mobility Group Box (TOX) gene, involved in immune function, was reduced. EIF2D expression was also altered in first-episode schizophrenia patients, but showing reduced levels. Any of the postmortem brain areas studied did not show differences of expression of both genes.
Conclusions
EIF2D and TOX are putative blood markers of chronic patients of schizophrenia, which expression change from the onset to the chronic disease, unraveling new biological pathways that can be used for the development of new intervention strategies in the diagnosis and prognosis of schizophrenia disease.Acknowledgments: This work was supported by Fondo de Investigación Sanitaria, Ministerio de Economía y Competitividad, Spain (PI10/01399, PI13/00447; PI17/00402, co-financed by FEDER) to J. Sanjuan and M.D. Moltó; Generalitat Valenciana PROMETEO Excellence Program, Spain (PROMETEO2016/082) to J Sanjuán. J Gilabert-Juan and N. Sebastiá-Ortega were recipients of research contracts from CIBERSAM, Spain. The RNA samples donated bythe Stanley Medical Research Institute Brain Collection were courtesy of Drs. Michael B. Knable, E. Fuller Torrey, Maree J. Webster, and Robert H. Yolken. The authors also
thank the collaboration of the staff members of the hospitals
Consumers’ willingness to pay for beef direct sales. A regional comparison across the Pyrenees
Willingness to pay (WTP) for direct market of beef is investigated in two Spanish and two French regions located on both sides of the Pyrenees. Given the novelty of this distribution system, especially in Spain, a contingent valuation approach is undertaken, and a double-bounded model is estimated. Different patterns of awareness, use and WTP are found across regions. Likewise, the profile of current and potential users of direct sale chains is investigated. Experience in the different stages involved from choice to final consumption of beef, intensity of varied beef consumption, familiarity with direct market of food in general,
and beef in particular, are some of the relevant factors to explain WTP and the probability of getting engaged into a direct distribution system of beef
Mid and late Holocene forest fires and deforestation in the subalpine belt of the Iberian range, northern Spain
26 Pags.- 6 Figs.- 2 Tabls. The definitive version is available at: http://link.springer.com/journal/11629The conversion of subalpine forests into grasslands for pastoral use is a well-known phenomenon, although for most mountain areas the timing of deforestation has not been determined. The presence of charcoal fragments in soil profiles affected by shallow landsliding enabled us to date the occurrence of fires and the periods of conversion of subalpine forest into grasslands in the Urbión Mountains, Iberian Range, Spain. We found that the treeline in the highest parts of the northwestern massifs of the Iberian Range (the Urbión, Demanda, Neila, and Cebollera massifs) is currently between 1500 and 1600 m a.s.l., probably because of pastoral use of the subalpine belt, whereas in the past it would have reached almost the highest divides (at approximately 2100–2200 m a.s.l.). The radiocarbon dates obtained indicate that the transformation of the subalpine belt occurred during the Late Neolithic, Chalcolithic, Bronze Age, Iron Age, and Middle Ages. Forest clearing was probably moderate during fires prior to the Middle Ages, as the small size of the sheep herds and the local character of the markets only required small clearings, and therefore more limited fires. Thus, it is likely that the forest recovered burnt areas in a few decades; this suggests the management of the forest and grasslands following a slash-and-burn system. During the Middle and Modern Ages deforestation and grassland expansion affected most of the subalpine belt and coincided with the increasing prevalence of transhumance, as occurred in other mountains in the Iberian Peninsula (particularly the Pyrenees). Although the occurrence of shallow landslides following deforestation between the Neolithic and the Roman Period cannot be ruled out, the most extensive shallow landsliding processes would have occurred from the Middle Ages until recent times.Support for this research was provided by the projects INDICA (CGL2011-
27753-C02-01 and -02) and DINAMO2 (CGL2012-33063), funded by the Spanish
Ministry of Economy and Competitiveness.Peer reviewe
Alterations of perineuronal nets in the dorsolateral prefrontal cortex of neuropsychiatric patients
Background: Alterations in the structure and physiology of interneurons in the prefrontal cortex (PFC) are important factors in the etiopathology of different psychiatric disorders. Among the interneuronal subpopulations, parvalbumin (PV) expressing cells appear to be specially affected. Interestingly, during development and adulthood the connectivity of these interneurons is regulated by the presence of perineuronal nets (PNNs), specialized regions of the extracellular matrix, which are frequently surrounding PV expressing neurons. Previous reports have found anomalies in the density of PNNs in the PFC of schizophrenic patients. However, although some studies have described alterations in PNNs in some extracortical regions of bipolar disorder patients, there are no studies focusing on the prefrontocortical PNNs of bipolar or major depression patients. For this reason, we have analyzed the density of PNNs in post-mortem sections of the dorsolateral PFC (DLPFC) from the Stanley Neuropathology Consortium, which includes controls, schizophrenia, bipolar and major depression patients. Results: We have not observed differences in the distribution of PV+ cells or PNNs, or in the percentage of PV+ interneurons surrounded by PNNs. The density of PV+ interneurons was similar in all the experimental groups, but there was a significantly lower density of PNNs in the DLPFC of bipolar disorder patients and a tendency towards a decrease in schizophrenic patients. No differences were found when evaluating the density of PV+ cells surrounded by PNNs. Interestingly, when assessing the influence of demographic data, we found an inverse correlation between the density of PNNs and the presence of psychosis. Conclusions: The present results point to prefrontocortical PNNs and their role in the regulation of neuronal plasticity as putative players in the etiopathology of bipolar disorder and schizophrenia. Our findings also suggest a link between these specialized regions of the extracellular matrix and the presence of psychosis
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