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Search Results: 1 - 10 of 384022 matches for " Martín-Pérez "
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La profesión dental en Espa?a. Análisis de la situación actual a partir de las ofertas formativas de educación continuada: Estudio piloto
Martín-Pérez,Ma Jesús; Mallo-Pérez,Luciano;
RCOE , 2003, DOI: 10.4321/S1138-123X2003000600002
Abstract: objective: to understand the current trends in the dental profession in spain, from the analysis of the offers for postgraduate studies. material and method: the analysis was performed on a total of 529 offers appearing on 3 consecutive issues of the journals gaceta dental (3 months) and maxillaris (3 months), between september 2002 and february 2003. their subject, duration and organizer were considered. in addition, the annual reports of the general council of the professional associations of odontology and stomatology of spain corresponding to the years 2002 and 2003 (203 entries) were analyzed. results: courses on implantology were the most frequently offered (27.5%), followed by those on orthodontics (17.6%) and periodontics (6.1%). most of the offers (68.5%) were organized by private initiatives. 43.3% were short courses, 27.8% were of intermediate duration and 27.8% of the courses offered more than 60 teachy hours. from the courses offered by the official professional associations of odontology and stomatology, 70.5% are technically or technologically oriented.
La eficiencia y el misreporting contable en las ONGD espa olas. Análisis de proyectos de cooperación internacional para el desarrollo
Natalia Martín-Cruz,Víctor Martín-Pérez,César Gámez-Alcalde
Academia : Revista Latinoamericana de Administración , 2012,
Abstract: El objetivo de este trabajo es valorar el comportamiento contable denominado misreporting de las organizaciones no gubernamentales para el desarrollo (ONGD) y evaluar sus consecuencias sobre la eficiencia en la ejecución de proyectos. En concreto, se selecciona una muestra de 52 proyectos financiados por la Agencia Espa ola de Cooperación Internacional para el Desarrollo (Aecid), se compara la imputación de las partidas de gasto realizadas por las ONGD a las partidas contables proporcionadas por la Aecid con las que se correspondería utilizando la clasificación del Plan General de Contabilidad Pública para valorar el misreporting, y se calcula la eficiencia de cada proyecto utilizando la metodología del análisis envolvente de datos (DEA, por sus siglas en inglés). Los resultados obtenidos muestran que la práctica de misreporting es habitual dentro del subsector de la cooperación al desarrollo y que contribuye a mejorar los niveles de eficiencia con los que se ejecutan los proyectos de cooperación internacional para el desarrollo.
Diagenesis of a drapery speleothem from Casta ar Cave: from dissolution to dolomitization
Martín-Pérez A.,Martín-García R.,Alonso-Zarza A.M.
International Journal of Speleology , 2012,
Abstract: A drapery speleothem (DRA-1) from Casta ar Cave in Spain was subjected to a detailed petrographical study in order to identify its primary and diagenetic features. The drapery’s present day characteristics are the result of the combined effects of the primary and diagenetic processes that DRA-1 underwent. Its primary minerals are calcite, aragonite and huntite. Calcite is the main constituent of the speleothem, whereas aragonite forms as frostwork over the calcite. Huntite is the main mineral of moonmilk which covers the tips of aragonite. These primary minerals have undergone a set of diagenetic processes, which include: 1) partial dissolution or corrosion that produces the formation of powdery matt-white coatings on the surface of the speleothem. These are seen under the microscope as dark and highly porous microcrystalline aggregates; 2) total dissolution produces pores of few cm2 in size; 3) calcitization and dolomitization of aragonite result in the thickening and lost of shine of the aragonite fibres. Microscopically, calcitization is seen as rhombohedral crystals which cover and replace aragonite forming mosaics that preserve relics of aragonite precursor. Dolomitization results in the formation of microcrystalline rounded aggregates over aragonite fibres. These aggregates are formed by dolomite crystals of around 1 μm size. The sequence of diagenetic processes follows two main pathways. Pathway 1 is driven by the increase of saturation degree and Mg/Ca ratio of the karstic waters and is visible in the NW side of the drapery. This sequence of processes includes: 1) aragonite and huntite primary precipitation and 2) dolomitization. Pathway 2 is driven by a decrease in the degree of saturation of calcite and aragonite and Mg/Ca ratio of the cave waters, and it is observed in the SE side of the drapery. The diagenetic processes of the second pathway include: 1) calcitization of aragonite; 2) incomplete dissolution (micritization) of both aragonite and calcite; 3) total dissolution. This study highlights the importance of diagenetic processes on speleothems and their complexity. The correct interpretation of these processes is crucial for the understanding of possible changes in the chemistry of waters, temperature, or pCO2 and so is critical to the correct interpretation of the paleoenvironmental significance of speleothems.
Absceso hepático piogénico como complicación de la enfermedad de Crohn
Martín-Pérez,E.; Galván,A.; Larra?aga,E.; Figueroa,J. M.; Serrano,P. A.;
Anales de Medicina Interna , 2000, DOI: 10.4321/S0212-71992000001200010
Abstract: pyogenic liver abscess in patients with chrohn's disease is not common, but the mortality has been reported to be high if diagnosis and treatment is delayed. intra-abdominal abscesses, fistulous disease, and steroid therapy have all beeen reported to be important predisponing factors in the pathogenesis of this entity. we present a patient with chrohn's disease in whom multiple abscesses were encountered in the right lobe of the liver. the diagnosis of liver abscess was established by abdominal computed tomography and the patient was treated by percutaneous catheter drainage. awareness of this rare complication is important because diagnosis is difficult to make and a high index of suspicion is required. once suspected, aggressive diagnostic workup and treatment is indicated. most patients with liver abscess can be successfully managed by percutaneous catheter drainage combined with antibiotic therapy if it is diagnosed before extensive necrosis has occurred.
The role of surface plasmon polaritons in the optical response of a hole pair
F. de León-Pérez,F. J. García-Vidal,L. Martín-Moreno
Physics , 2010, DOI: 10.1103/PhysRevB.84.125414
Abstract: The optical emittance of a hole pair perforated in an opaque metal film is studied from first-principles using the coupled-mode method. The geometrical simplicity of this system helps to understand the fundamental role played by surface plasmon polaritons (SPPs) in its optical response. A SPP interference model without fitting parameters is developed from the rigorous solution of Maxwell's equations. The calculations show that the interference pattern of the hole pair is determined by two scattering mechanisms: (i) re-illumination of the holes by the in-plane SPP radiation and (ii) an effective impedance depending on the single-hole response. The conditions for constructive and destructive interference only depend on the phase difference provided by each of the two scattering mechanisms.
Transmittance of a subwavelength aperture flanked by a finite groove array \\ placed near the focus of a conventional lens
F. Villate-Guío,F. de León-Pérez,L. Martín-Moreno
Physics , 2014, DOI: 10.1364/JOSAB.31.001653
Abstract: One-dimensional light harvesting structures illuminated by a conventional lens are studied in this paper. Our theoretical study shows that high transmission efficiencies are obtained when the structure is placed near the focal plane of the lens. The considered structure is a finite slit-groove array (SGA) with a given number of grooves that are symmetrically distributed with respect to a central slit. The SGA is nano-patterned on an opaque metallic film. It is found that a total transmittance of 80% is achieved even for a single slit when (i) Fabry-Perot like modes are excited inside the slit and (ii) the effective cross section of the aperture becomes of the order of the full width at half maximum of the incident beam. A further enhancement of 8% is produced by the groove array. The optimal geometry for the groove array consists of a moderate number of grooves ($ \geq 4$) at either side of the slit, separated by a distance of half the incident wavelength $\lambda$. Grooves should be deeper (with depth $\geq \lambda/4$) than those typically reported for plane wave illumination in order to increase their individual scattering cross section.
Mechanisms for photon sorting based on slit-groove arrays
F. Villate-Guío,L. Martín-Moreno,F. de León-Pérez
Physics , 2014, DOI: 10.1016/j.photonics.2014.10.003
Abstract: Mechanisms for one-dimensional photon sorting are theoretically studied in the framework of a couple mode method. The considered system is a nanopatterned structure composed of two different pixels drilled on the surface of a thin gold layer. Each pixel consists of a slit-groove array designed to squeeze a large fraction of the incident light into the central slit. The Double-Pixel is optimized to resolve two different frequencies in the near infrared. This system shows a high transmission efficiency and a small crosstalk. Its response is found to strongly depend on the effective area shared by overlapping pixels. Three different regimes for the process of photon sorting are identified and the main physical trends underneath in such regimes are unveiled. Optimal efficiencies for the photon sorting are obtained for a moderate number of grooves that overlap with grooves of the neighbor pixel. Results could be applied to optical and infrared detectors.
Mercury in Canned Tuna in Spain. Is Light Tuna Really Light?  [PDF]
Montserrat González-Estecha, María José Martínez-García, Manuel Fuentes-Ferrer, Andrés Bodas-Pinedo, Alfonso Calle-Pascual, José María Ordó?ez-Iriarte, Cristina Fernández-Pérez, Nieves Martell-Claros, Miguel ángel Rubio-Herrera, Emilia Gómez-Hoyos, José Jesús Guillén-Pérez
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.47A007
Abstract:

In Spain, certain population-based studies have shown high blood mercury (Hg) levels due to the high consumption of fish. Some studies have stated that one of the most consumed fish in Spain is canned tuna. Different Spanish organisms consider that it is safe to consume canned tuna as it supposedly has a low mercury content, particularly in so-called light tuna. However, in Spain light tuna is mainly yellowfin and bigeye tuna, while in other countries it is mainly skipjack tuna. This study analyzed 36 cans of the most popular brands in Spain and examined the influence of the type of tuna, packaging medium (olive oil, sunflower seed oil, water or marinade), different brands, prices and expiration dates. Mercury concentrations (mg/kg) were measured by atomic absorption spectrometry and thermal decomposition amalgamation. The medians observed were (mg/kg): light tuna: 0.314; IQR: 0.205 - 0.594, white tuna: 0.338; IQR: 0.276 - 0.558, skipjack: 0.311; IQR: 0.299 - 0.322, frigate tuna: 0.219; IQR 0.182 - 0.257 and mackerel: 0.042; IQR 0.029 - 0.074. We found statistically significant differences between white tuna, light tuna and mackerel (p = 0.004); light tuna and mackerel (p = 0.002) and white tuna and mackerel (p = 0.006). However, we found no differences between white tuna and light tuna, or among packaging medium, brands, prices or expiration dates. The limit of 0.500 mg/kg of mercury in canned tuna was exceeded by the following percentages of the cans: 33.3% of light tuna, 16.7% of white tuna, and 0% of Skipjack, frigate tuna and mackerel. The mercury content of the cans of Spanish light tuna that were analyzed was variable and high. The results of this study indicate that stricter regulation of Hg in canned tuna is necessary. Until then, it is safer to recommend that vulnerable populations such as children and pregnant women consume canned mackerel, which has a markedly lower mercury content.

Jejunal diverticular perforation due to gallstone ileus Perforación de divertículo yeyunal secundaria a íleo biliar
Jesica Martín-Pérez,Alberto Bravo-Gutiérrez,Luciano Delgado-Plasencia,Carmen Nieves Hernández-León
Revista Espa?ola de Enfermedades Digestivas , 2012,
Abstract:
Optimal light harvesting structures at optical and infrared frequencies
F. Villate-Guío,F. López-Tejeira,F. J. García-Vidal,L. Martín-Moreno,F. de León-Pérez
Physics , 2012, DOI: 10.1364/OE.20.025441
Abstract: One-dimensional light harvesting structures with a realistic geometry nano-patterned on an opaque metallic film are optimized to render high transmission efficiencies at optical and infrared frequencies. Simple design rules are developed for the particular case of a slit-groove array with a given number of grooves that are symmetrically distributed with respect to a central slit. These rules take advantage of the hybridization of Fabry-Perot modes in the slit and surface modes of the corrugated metal surface. Same design rules apply for optical and infrared frequencies. The parameter space of the groove array is also examined with a conjugate gradient optimization algorithm that used as a seed the geometries optimized following physical intuition. Both uniform and nonuniform groove arrays are considered. The largest transmission enhancement, with respect to a uniform array, is obtained for a chirped groove profile. Such enhancement is a function of the wavelength. It decreases from 39% in the optical part of the spectrum to 15% at the long wavelength infrared.
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