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Search Results: 1 - 10 of 312896 matches for " José R Fernández "
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Auto-adaptative Laplacian Pyramids for High-dimensional Data Analysis
ángela Fernández,Neta Rabin,Dalia Fishelov,José R. Dorronsoro
Computer Science , 2013,
Abstract: Non-linear dimensionality reduction techniques such as manifold learning algorithms have become a common way for processing and analyzing high-dimensional patterns that often have attached a target that corresponds to the value of an unknown function. Their application to new points consists in two steps: first, embedding the new data point into the low dimensional space and then, estimating the function value on the test point from its neighbors in the embedded space. However, finding the low dimension representation of a test point, while easy for simple but often not powerful enough procedures such as PCA, can be much more complicated for methods that rely on some kind of eigenanalysis, such as Spectral Clustering (SC) or Diffusion Maps (DM). Similarly, when a target function is to be evaluated, averaging methods like nearest neighbors may give unstable results if the function is noisy. Thus, the smoothing of the target function with respect to the intrinsic, low-dimensional representation that describes the geometric structure of the examined data is a challenging task. In this paper we propose Auto-adaptive Laplacian Pyramids (ALP), an extension of the standard Laplacian Pyramids model that incorporates a modified LOOCV procedure that avoids the large cost of the standard one and offers the following advantages: (i) it selects automatically the optimal function resolution (stopping time) adapted to the data and its noise, (ii) it is easy to apply as it does not require parameterization, (iii) it does not overfit the training set and (iv) it adds no extra cost compared to other classical interpolation methods. We illustrate numerically ALP's behavior on a synthetic problem and apply it to the computation of the DM projection of new patterns and to the extension to them of target function values on a radiation forecasting problem over very high dimensional patterns.
Evolución del Contenido de Azufre en la Gasolina Comercializada en Galicia (Espa?a) como Consecuencia de la Aplicación del Real Decreto 1700/2003
Fernández-Feal,Coro; Fernández-Feal,Luisa; Escudero,Paola; Pérez-Prado,José R;
Información tecnológica , 2009, DOI: 10.4067/S0718-07642009000100007
Abstract: the objective of the study was to determine the sulphur content in gasoline which were commercialized in galicia six months before and six months after the first of january 2005, the date established by law, according to the royal decree 1700/2003, to reduce the sulphur content in gasoline. this was done to verify the fulfilment of the new legislation starting that date: 150 mg/kg in the period july to december 2004 and 50 mg/kg in the period january to june 2005. the sulphur content in the samples was determined according to a normalized procedure adapted to this type of product. all gasoline samples presented sulphur content lower than the maximum limit established by the legislation. these results show the fast adaptation performed by the refineries in their desulphurization processes to comply with the new legislation.
Evolución del Contenido de Azufre en la Gasolina Comercializada en Galicia (Espa a) como Consecuencia de la Aplicación del Real Decreto 1700/2003 Evolution of Sulphur Content in Commercialized Gasoline in Galicia (Spain) as a Result of the Application of the Royal Decree 1700/2003
Coro Fernández-Feal,Luisa Fernández-Feal,Paola Escudero,José R Pérez-Prado
Información Tecnológica , 2009,
Abstract: El objetivo de este estudio fue determinar la cantidad de azufre contenida en las gasolinas comercializadas en Galicia antes y después del 1 de enero de 2005, fecha establecida por ley, según Real Decreto 1700/2003, para la disminución del contenido de azufre en gasolinas. Esto se realizó con el fin de verificar el cumplimiento de la legislación vigente a partir de esa fecha: 150 mg/kg en el periodo de julio a diciembre de 2004 y 50 mg/kg a partir de enero de 2005. La determinación del contenido de azufre en las muestras recogidas se realizó empleando el procedimiento normalizado adaptado a este tipo de producto. La totalidad de las gasolinas analizadas presentaron un contenido de azufre inferior al límite máximo establecido por la legislación. Estos resultados muestran la rápida adaptación llevada a cabo por las refinerías en sus procesos de desulfurización para cumplir con la nueva legislación. The objective of the study was to determine the sulphur content in gasoline which were commercialized in Galicia six months before and six months after the first of January 2005, the date established by law, according to the royal decree 1700/2003, to reduce the sulphur content in gasoline. This was done to verify the fulfilment of the new legislation starting that date: 150 mg/kg in the period July to December 2004 and 50 mg/kg in the period January to June 2005. The sulphur content in the samples was determined according to a normalized procedure adapted to this type of product. All gasoline samples presented sulphur content lower than the maximum limit established by the legislation. These results show the fast adaptation performed by the refineries in their desulphurization processes to comply with the new legislation.
Hiperobesidad y obesidad mórbida: estudio comparativo Hiperobesity v/s morbid obesity: a comparative study
Enrique Lanzarini S,Andrés Marambio G,Lara Fernández R,José Lasnibat R
Revista Chilena de Cirugía , 2012,
Abstract: Introducción: La cirugía bariátrica es efectiva y segura en el tratamiento de obesos con IMC > 40, sin embargo, a mayor peso preoperatorio podría aumentar la morbimortalidad. Objetivo: Describir y comparar los resultados perioperatorios y a mediano plazo entre hiperobesos y obesos mórbidos sometidos a bypass gástrico. Material y Método: Estudio prospectivo de pacientes hiperobesos operados de bypass gástrico los últimos 10 a os. Se analizaron características clínicas, morbimortalidad perioperatoria y resolución de comorbilidades. Se compararon los resultados con un grupo de obesos mórbidos pareados por edad y sexo. Resultados: Se operaron 146 hiperobesos, que fueron comparados con 165 obesos mórbidos. El 66,8% fueron mujeres y el promedio de edad fue 39,9 ± 12,4 a os, no encontramos diferencias significativas entre ambos grupos por sexo y edad. El IMC promedio fue 53 y 44,4 respectivamente. El 21,5% tenía diabetes mellitus 2, el 39,5% hipertensión arterial, el 31% dislipidemia y el 8,4% artrosis, sin encontrar diferencias significativas, a excepción de una mayor prevalencia de dislipidemia en los obesos mórbidos (p = 0,001). Un 10,4% presentó complicaciones quirúrgicas durante el postoperatorio, no existiendo diferencias entre ambos grupos (p = 0,24). Al a o todos los pacientes presentaban un descenso significativo del peso, sin embargo, los hiperobesos presentaban un descenso más acentuado (p = 0,001). Los niveles de glicemia en ayunas, colesterol y triglicéridos también presentaron un descenso significativo sin lograr diferencias entre ambos grupos. Conclusiones: El bypass gástrico es efectivo en la baja de peso y resolución de comorbilidades tanto en obesos mórbidos como hiperobesos, sin presentar diferencias significativas en las complicaciones quirúrgicas y mortalidad. Introduction: Bariatric surgery is effective and safe in treating obese patients with BMI > 40, however, higher preoperative weight could increases morbidity and mortality. Aim: To describe and compare the perioperative and mid term outcomes between hiperobese and morbidly obese patients submitted to gastric bypass. Material and Method: A prospective study of hiperobese patients submitted to gastric bypass over the past 10 years. We analyzed clinical characteristics, perioperative morbimortality and resolution of comor-bidities. The results were compared with a group of morbidly obese patients matched by age and sex. Results: 146 hiperobese were operated and compared with 165 morbidly obese patients. 66.8% were female and the average age of the total group was 39.9 ± 12.4 years, with
Protozoan Parasites of Bivalve Molluscs: Literature Follows Culture
José A. Fernández Robledo, Gerardo R. Vasta, Nicholas R. Record
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100872
Abstract: Bivalve molluscs are key components of the estuarine environments as contributors to the trophic chain, and as filter –feeders, for maintaining ecosystem integrity. Further, clams, oysters, and scallops are commercially exploited around the world both as traditional local shellfisheries, and as intensive or semi–intensive farming systems. During the past decades, populations of those species deemed of environmental or commercial interest have been subject to close monitoring given the realization that these can suffer significant decline, sometimes irreversible, due to overharvesting, environmental pollution, or disease. Protozoans of the genera Perkinsus, Haplosporidium, Marteilia, and Bonamia are currently recognized as major threats for natural and farmed bivalve populations. Since their identification, however, the variable publication rates of research studies addressing these parasitic diseases do not always appear to reflect their highly significant environmental and economic impact. Here we analyzed the peer– reviewed literature since the initial description of these parasites with the goal of identifying potential milestone discoveries or achievements that may have driven the intensity of the research in subsequent years, and significantly increased publication rates. Our analysis revealed that after initial description of the parasite as the etiological agent of a given disease, there is a time lag before a maximal number of yearly publications are reached. This has already taken place for most of them and has been followed by a decrease in publication rates over the last decade (20– to 30– year lifetime in the literature). Autocorrelation analyses, however, suggested that advances in parasite purification and culture methodologies positively drive publication rates, most likely because they usually lead to novel molecular tools and resources, promoting mechanistic studies. Understanding these trends should help researchers in prioritizing research efforts for these and other protozoan parasites, together with their development as model systems for further basic and translational research in parasitic diseases.
Cirugía videolaparoscópica en urgencias
Fernández Santiesteban,Llipsy; Silvera García,José R; Díaz Calderín,José M; Vilorio Haza,Pedro; Loys Fernández,Jorge L;
Revista Cubana de Cirug?-a , 2003,
Abstract: a cross-sectional, prospective and descriptive study was conducted among those patients operated on by the video-assisted laparoscopic technique from october, 1995, to march, 2001. 151 patients underwent surgery by using this method. the diseases treated were acute cholecystitis (45.7 %), acute appendicitis (37.8 %), gynecological diseases and of other type (12.6 and 3.9 %, respectively), the average surgical time was 45 minuntes. the conversion index (only present in cholecystectomies) was 3.8 %. the trans- and postoperative complications were observed in 8.6 and 2.6 %, respectively. there were no deaths. experience showed that video-assisted laparoscopic surgery is an excellent procedure to treat several surgical emergencies
Cirugía videolaparoscópica en urgencias
Fernández Santiesteban,Llipsy; Silvera García,José R; Díaz Calderín,José M; Vilorio Haza,Pedro; Loys Fernández,Jorge L;
Revista Cubana de Cirug?-a , 2003,
Abstract: a cross-sectional, prospective and descriptive study of the patients that underwent emergency surgery by the video-assisted laparoscopic technique, from october, 1995, to march, 2001, was conducted. 151 patients were operated on by using this procedure. the diseases treated were acute cholecystitis (45.7 %), acute appendicitis (37.8 %), gynecological diseases and of other type (12.6 and 3.9 %, respectively). the average surgical time was 45 min. the conversion index (only present in colecystectomies) was 3.8 %. the trans- and postoperative complications were observed in 8.6 and 2.6 %, respectively. there were no deaths. our experience shows that the video-assisted laparoscopic surgery is an excellent procedure to treat many emergency surgical diseases
Reintervenciones de urgencia en cirugía videolaparoscópica
Fernández Santiesteban,Llipsy; Silvera García,José R; Díaz Calderín,José M; Vilorio Haza,Pedro; Loys Fernández,Jorge L;
Revista Cubana de Cirug?-a , 2003,
Abstract: laparoscopy is not a new way to establish the diagnosis of abdominal emergencies. the experience has showed that it is not only feasible, but more advantageous to carry out the definitive treatment of the cases complicated in elective video-assisted laparoscopic surgery by using this approach, provided that the patients' conditions (general and local) allow it. a prospective, longitudinal and descriptive study of the emergency reoperations was conducted by using the video-assisted laparoscopic technique, from october, 1995, to march, 2001. the results obtained in 13 of these patients reoperated on by minimal invasive surgery at "hermanos ameijeiras" clinical and surgical hospital were presented. among the previously performed operations that gave place to the present complication, we found video-assisted laparoscopic cholecystectomy (11 cases) and gynecological operations (2 cases). 6 hemoperitoneums, 5 bilirhachias and 2 intraabdominal abscesses were diagnosed. the treatment applied to all cases was lavage and drainage of the cavity. the previous procedure was associated with a retrograde endoscopic cholangiopancreatography in 3 patients. the average surgical time was 46 min and the hospital stay was less than 72 hours in 5 cases. the video-assisted laparoscopic treatment may be successfully used in patients complicated in the elective minimal invasive surgery
Human LDL Structural Diversity Studied by IR Spectroscopy
José A. Fernández-Higuero, Ana M. Salvador, Cesar Martín, José Carlos G. Milicua, José L. R. Arrondo
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0092426
Abstract: Lipoproteins are responsible for cholesterol traffic in humans. Low density lipoprotein (LDL) delivers cholesterol from liver to peripheral tissues. A misleading delivery can lead to the formation of atherosclerotic plaques. LDL has a single protein, apoB-100, that binds to a specific receptor. It is known that the failure associated with a deficient protein-receptor binding leads to plaque formation. ApoB-100 is a large single lipid-associated polypeptide difficulting the study of its structure. IR spectroscopy is a technique suitable to follow the different conformational changes produced in apoB-100 because it is not affected by the size of the protein or the turbidity of the sample. We have analyzed LDL spectra of different individuals and shown that, even if there are not big structural changes, a different pattern in the intensity of the band located around 1617 cm?1 related with strands embedded in the lipid monolayer, can be associated with a different conformational rearrangement that could affect to a protein interacting region with the receptor.
Nucleophilic Benzoylation Using a Mandelic Acid Dioxolanone as a Synthetic Equivalent of the Benzoyl Carbanion. Oxidative Decarboxylation of α-Hydroxyacids
Gonzalo Blay,Isabel Fernández,Belén Monje,José R. Pedro
Molecules , 2004, DOI: 10.3390/90500365
Abstract: The synthesis of alkyl aryl ketones using a mandelic acid dioxolanone as a synthetic equivalent (Umpolung) of the benzoyl carbanion is reported. The methodology involves alkylation of the mandelic acid dioxolanone, hydrolysis of the dioxolanone moiety in the alkylated products and oxidative decarboxylation of the resulting α-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co (III) complex in the presence of pivalaldehyde under very mild conditions.
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