953 resultados para GONZÁLEZ SUÁREZ, FEDERICO, 1844–1917


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The study of the Upper Jurassic-Lower Cretaceous deposits (Higueruelas, Villar del Arzobispo and Aldea de Cortés Formations) of the South Iberian Basin (NW Valencia, Spain) reveals new stratigraphic and sedimentological data, which have significant implications on the stratigraphic framework, depositional environments and age of these units. Moreover, these new data encourage revising the previously proposed stratigraphic correlations between the studied units and those deposited in adjacent areas of the Iberian Basin. The Higueruelas Fm was deposited in a mid-inner carbonate platform where oncolitic bars migrated by the action of storms and where oncoid production progressively decreased towards the uppermost part of the unit. The overlying Villar del Arzobispo Fm has been traditionally interpreted as an inner platform-lagoon evolving into a tidal-flat. Here it is interpreted as an inner-carbonate platform affected by storms, where oolitic shoals protected a lagoon, which had siliciclastic inputs from the continent. The Aldea de Cortés Fm has been previously interpreted as a lagoon surrounded by tidal-flats and fluvial-deltaic plains. Here it is reinterpreted as a coastal wetland where siliciclastic muddy deposits interacted with shallow fresh to marine water bodies, aeolian dunes and continental siliciclastic inputs. The contact between the Higueruelas and Villar del Arzobispo Fms, classically defined as gradual, is interpreted here as gradual and rapid, because the transition between both units comprises few meters. More importantly, the contact between the Villar del Arzobispo and Aldea de Cortés Fms, previously considered as unconformable, is here interpreted as gradual. The presence of Alveosepta in the Villar del Arzobispo Fm suggests that at least part of this unit is Kimmeridgian, unlike the previously assigned Late Tithonian-Middle Berriasian age. Consequently, the underlying Higueruelas Fm, previously considered Tithonian, should not be younger than Kimmeridgian. Accordingly, sedimentation of the Aldea de Cortés Fm, previously considered Valanginian-Hauterivian, probably started during the Tithonian and it may be considered part of the regressive trend of the Late Jurassic-Early Cretaceous cycle. This is consistent with the dinosaur faunas, typically Jurassic, described in the Villar del Arzobispo and Aldea de Cortés Fms.

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We introduce a general class of su(1|1) supersymmetric spin chains with long-range interactions which includes as particular cases the su(1|1) Inozemtsev (elliptic) and Haldane-Shastry chains, as well as the XX model. We show that this class of models can be fermionized with the help of the algebraic properties of the su(1|1) permutation operator and take advantage of this fact to analyze their quantum criticality when a chemical potential term is present in the Hamiltonian. We first study the low-energy excitations and the low-temperature behavior of the free energy, which coincides with that of a (1+1)-dimensional conformal field theory (CFT) with central charge c=1 when the chemical potential lies in the critical interval (0,E(π)), E(p) being the dispersion relation. We also analyze the von Neumann and Rényi ground state entanglement entropies, showing that they exhibit the logarithmic scaling with the size of the block of spins characteristic of a one-boson (1+1)-dimensional CFT. Our results thus show that the models under study are quantum critical when the chemical potential belongs to the critical interval, with central charge c=1. From the analysis of the fermion density at zero temperature, we also conclude that there is a quantum phase transition at both ends of the critical interval. This is further confirmed by the behavior of the fermion density at finite temperature, which is studied analytically (at low temperature), as well as numerically for the su(1|1) elliptic chain.

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We introduce a new class of generalized isotropic Lipkin–Meshkov–Glick models with su(m+1) spin and long-range non-constant interactions, whose non-degenerate ground state is a Dicke state of su(m+1) type. We evaluate in closed form the reduced density matrix of a block of Lspins when the whole system is in its ground state, and study the corresponding von Neumann and Rényi entanglement entropies in the thermodynamic limit. We show that both of these entropies scale as a log L when L tends to infinity, where the coefficient a is equal to (m  −  k)/2 in the ground state phase with k vanishing magnon densities. In particular, our results show that none of these generalized Lipkin–Meshkov–Glick models are critical, since when L-->∞ their Rényi entropy R_q becomes independent of the parameter q. We have also computed the Tsallis entanglement entropy of the ground state of these generalized su(m+1) Lipkin–Meshkov–Glick models, finding that it can be made extensive by an appropriate choice of its parameter only when m-k≥3. Finally, in the su(3) case we construct in detail the phase diagram of the ground state in parameter space, showing that it is determined in a simple way by the weights of the fundamental representation of su(3). This is also true in the su(m+1) case; for instance, we prove that the region for which all the magnon densities are non-vanishing is an (m  +  1)-simplex in R^m whose vertices are the weights of the fundamental representation of su(m+1).

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Fundamento: La asociación de la inmigración con el bajo peso al nacimiento (BP) y el parto pretérmino (PP) es un importante indicador de inequidades en salud. El objetivo de este estudio es analizar las diferencias entre BP y el PP según la nacionalidad de la madre. Métodos: Los datos proceden del Boletín Estadístico de Nacimientos. Durante el período de estudio hubo 1.878.718 recién nacidos. La nacionalidad fue considerada como variable de exposición (española-inmigrante). Las variables de efecto son BP (nacimientos de 37 o más semanas de gestación con un peso inferior a 2.500 gramos) y PP (recién nacidos con menos de 37 semanas de gestación). Se calcularon odds ratios simples y ajustadas por posibles variables de confusión mediante regresión logística. Resultados: La prevalencia de BP y PP entre las mujeres españolas fue de 7,9% y 3,2% respectivamente, mientras que en las extranjeras fue de 7,3% y 2,4% respectivamente. En comparación con las españolas, el riesgo más bajo de PP lo presentaron las mujeres procedentes de África del Norte (ORa= 0,77 IC95%0,74-0,80). Con respecto al BP el riesgo más bajo se observó en madres de Sudamérica (ORa=0,62 IC95%0,59-0,65) y Europa del Este (ORa=0,65 IC95%0,60-0,71). Conclusión: Los recién nacidos de madre extranjera presentan menos riesgo de BP y PP que los autóctonos, posiblemente como consecuencia del sesgo por la condición de ser inmigrante sano y por la menor frecuencia de prácticas de riesgo durante la gestación de las mujeres inmigrantes.

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Background: Access to health services is an important health determinant. New research in health equity is required, especially amongst economic migrants from developing countries. Studies conducted on the use of health services by migrant populations highlight existing gaps in understanding which factors affect access to these services from a qualitative perspective. We aim to describe the views of the migrants regarding barriers and determinants of access to health services in the international literature (1997–2011). Methods: A systematic review was conducted for Qualitative research papers (English/Spanish) published in 13 electronic databases. A selection of articles that accomplished the inclusion criteria and a quality evaluation of the studies were carried out. The findings of the selected studies were synthesised by means of metasynthesis using different analysis categories according to Andersen’s conceptual framework of access and use of health services and by incorporating other emergent categories. Results: We located 3,025 titles, 36 studies achieved the inclusion criteria. After quality evaluation, 28 articles were definitively synthesised. 12 studies (46.2%) were carried out in the U.S and 11 studies (42.3%) dealt with primary care services. The participating population varied depending mainly on type of host country. Barriers were described, such as the lack of communication between health services providers and migrants, due to idiomatic difficulties and cultural differences. Other barriers were linked to the economic system, the health service characteristics and the legislation in each country. This situation has consequences for the lack of health control by migrants and their social vulnerability. Conclusions: Economic migrants faced individual and structural barriers to the health services in host countries, especially those with undocumented situation and those experimented idiomatic difficulties. Strategies to improve the structures of health systems and social policies are needed.

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Objectives: To analyse the association between self-perceived discrimination and social determinants (social class, gender, country of origin) in Spain, and further to describe contextual factors which contribute to self-perceived discrimination. Methods: Cross-sectional design using data from the Spanish National Health Survey (2006). The dependent variable was self-perceived discrimination, and independent and stratifying variables were sociodemographic characteristics (e.g. sex, social class, country of origin, educational level). Logistic regression was used. Results: The prevalence of self-perceived discrimination was 4.2% for men and 6.3% for women. The likelihood of self-perceived discrimination was higher in people who originated from low-income countries: men, odds ratio (OR) 5.59 [95% confidence interval (CI) 4.55–6.87]; women, OR 4.06 (95% CI 3.42–4.83). Women were more likely to report self-perceived discrimination by their partner at home than men [OR 8.35 (95% CI 4.70–14.84)]. The likelihood of self-perceived discrimination when seeking work was higher among people who originated from low-income countries than their Spanish counterparts: men, OR 13.65 (95% CI 9.62–19.35); women, OR 10.64 (95% CI 8.31–13.62). In comparison with Spaniards, male white-collar workers who originated from low-income countries [OR 11.93 (95% CI 8.26–17.23)] and female blue-collar workers who originated from low-income countries (OR 1.6 (95% CI 1.08–2.39)] reported higher levels of self-perceived discrimination. Conclusions: Self-perceived discrimination is distributed unevenly in Spain and interacts with social inequalities. This particularly affects women and immigrants.

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Unlike other dung beetles, the Iberian geotrupid Thorectes lusitanicus exhibits polyphagous behavior; for example, it is able to eat acorns, fungi, fruits, and carrion in addition to the dung of different mammals. This adaptation to digest a wider diet has physiological and developmental advantages and requires key changes in the composition and diversity of the beetle's gut microbiota. In this study, we isolated aerobic, facultative anaerobic, and aerotolerant microbiota amenable to grow in culture from the gut contents of T. lusitanicus and resolved isolate identity to the species level by sequencing 16S rRNA gene fragments. Using BLAST similarity searches and maximum likelihood phylogenetic analyses, we were able to reveal that the analyzed fraction (culturable, aerobic, facultative anaerobic, and aerotolerant) of beetle gut microbiota is dominated by the phyla Proteobacteria, Firmicutes and Actinobacteria. Among Proteobacteria, members of the order Enterobacteriales (Gammaproteobacteria) were the most abundant. The main functions associated with the bacteria found in the gut of T. lusitanicus would likely include nitrogen fixation, denitrification, detoxification, and diverse defensive roles against pathogens.

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El objetivo es analizar las condiciones de trabajo en inmigrantes colombianos y sus problemas de salud asociados. Para tal fin, se realizó un estudio epidemiológico descriptivo, en población inmigrante colombiana trabajadora activa o en paro, mediante encuesta personal, recogiendo información sobre características personales y laborales e indicadores de salud. Los resultados indican que existe un porcentaje importante de inmigrantes con contrataciones temporales o sin contrato y jornadas de trabajo semanales por encima de las 40 horas. Una quinta parte no se encuentra de alta en la seguridad social. La gran mayoría de las mujeres (92%) tienen salarios menores o iguales a los 1.200 euros. La población percibe discriminación en espacios sociales y laborales. Se reportan problemas de salud con diferencias por sexo. Casi una tercera parte no ha recibido información sobre prevención de accidentes y daños a la salud. Se evidencian así, situaciones de precariedad que exigen estrategias para garantizar mecanismos de protección social para esta población.

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Hoy en día es común estudiar los patrones globales de biodiversidad a partir de las predicciones generadas por diferentes modelos de nicho ecológico. Habitualmente, estos modelos se calibran con datos procedentes de bases de datos de libre acceso (e.g. GBIF). Sin embargo, a pesar de la facilidad de descarga y de la accesibilidad de los datos, la información almacenada sobre las localidades donde están presentes las especies suele tener sesgos y errores. Estos problemas en los datos de calibración pueden modificar drásticamente las predicciones de los modelos y con ello pueden enmascarar los patrones macroecológicos reales. El objetivo de este trabajo es investigar qué métodos producen resultados más precisos cuando los datos de calibración incluyen sesgos y cuáles producen mejores resultados cuando los datos de calibración tienen, además de sesgos, errores. Para ello creado una especie virtual, hemos proyectado su distribución en la península ibérica, hemos muestreado su distribución de manera sesgada y hemos calibrado dos tipos de modelos de distribución (Bioclim y Maxent) con muestras de distintos tamaños. Nuestros resultados indican que cuando los datos sólo están sesgados, los resultados de Bioclim son mejores que los de Maxent. Sin embargo, Bioclim es extremadamente sensible a la presencia de errores en los datos de calibración. En estas situaciones, el comportamiento de Maxent es mucho más robusto y las predicciones que proporciona son más ajustadas.

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Background: Intimate partner violence (IPV) against women occurs in all countries, all cultures and at every level of society; however, some populations may be at greater risk than others. The aim of this study was to explore IPV prevalence among Ecuadorian, Moroccan and Romanian immigrant women living in Spain and its possible association with their personal, family, social support and immigration status characteristics. Methods: Cross-sectional study of 1607 adult immigrant women residing in Barcelona, Madrid and Valencia (2011). Prevalence rates and adjusted odds ratios (AORs) were calculated, with current IPV being the outcome. Different women’s personal (demographic), family, social support and immigration status characteristics were considered as explicative and control variables. All analyses were separated by women’s country of origin. Results: Current IPV prevalence was 15.57% in Ecuadorians, 10.91% in Moroccans and 8.58% in Romanians. Some common IPV factors were found, such as being separated and/or divorced. In Romanians, IPV was also associated with lack of social support [AOR 5.96 (1.39–25.62)] and low religious involvement [AOR 2.17 (1.06–4.43)]. The likelihood of current IPV was lower among women without children or other dependants in this subgroup [AOR 0.29 (0.093–0.92)]. Conclusion: The IPV prevalence rates obtained for Moroccan, Romanian and Ecuadorian women residing in Spain were similar. Whereas the likelihood of IPV appeared to be relatively evenly distributed among Moroccan and Ecuadorian women, it was higher among Romanian women in socially vulnerable situations related to family responsibilities and the lack of support networks. The importance of intervention in the process of separation and divorce was common to all women.

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Objective. To synthesise the scientific evidence concerning barriers to health care access faced by migrants. We sought to critically analyse this evidence with a view to guiding policies. Design. A systematic review methodology was used to identify systematic and scoping reviews which quantitatively or qualitatively analysed data from primary studies. The main variables analysed were structural and contextual barriers (health system organisation) as well as individual (patients and providers). The quality of evidence from the systematic reviews was critically appraised. From 2674 reviews, 79 were retained for further scrutiny, and finally 9 met the inclusion criteria. Results. The structural barriers identified were the lack of health insurance and the high cost of drugs (non-universal health system) and organisational aspects of health system (social insurance system and national health system). The individual barriers were linguistic and cultural. None of the reviews provided a quality appraisal of the studies. Conclusions. Barriers to health care for migrants range from entitlement in non-universal health systems to accessibility in universal ones, and determinants of access to the respective health services should be analysed within the corresponding national context. Generate social and institutional changes that eliminate barriers to access to health services is essential to ensure health for all.

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La WebQuest responde a una estrategia didáctica basada en la incorporación de las TIC en el aula, cuyo sustento teórico está en las corrientes constructivistas y el aprendizaje colaborativo, siendo de este modo pertinente a las directrices del EEES. En virtud de ello, nos hemos propuesto enfocar nuestras prácticas docentes aprovechando dicha estrategia didáctica y los recursos disponibles en la Web 2.0. Ahora bien, consideramos que como paso previo a la implementación de cualquier recurso TIC necesitamos tener un profundo conocimiento sobre el mismo. Es por ello que, para el desarrollo del trabajo, hemos considerado llevar a cabo un proceso gradual dividido en tres fases. La primera, centrada en la apropiación de la WebQuest como herramienta metodológica, la unificación de criterios y significados en torno al qué, al cómo y al para qué de su implementación. La segunda, focalizada en el diseño de WebQuest y la generación de espacios colaborativos de evaluación de las mismas. La tercera, enfatiza la aplicación directa de WebQuest en nuestras clases y el seguimiento de éstas con fines investigativos. En esta comunicación damos cuenta del proceso llevado a cabo en la primera fase, destacando la multidisciplinaridad que caracteriza al equipo de trabajo.

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Contribuir a la mejora de la calidad de la enseñanza y de los resultados de aprendizaje constituye uno de los retos en el sistema universitario actual que exige un gran esfuerzo de coordinación en las acciones de investigación e innovación a desarrollar. Para alcanzar este propósito, desde el grupo de investigación EDUTIC-ADEI (VIGROB-039) de la Universidad de Alicante se ha promovido la constitución de una red docente interdepartamental e interuniversitaria que pretende investigar sobre cómo debe ser la enseñanza online que se desarrolla en el ámbito universitario. Para ello, se ha abordado el concepto de ambiente de aprendizaje en este contexto virtual con el fin de delimitar los parámetros que deben definir una enseñanza de calidad cuando hablamos de e-learning, Masive Open Online Courses [MOOCs], Personal Learning Environment [PLE], etc. La investigación, pues, ahonda en los aspectos curriculares que conforman dichos ambientes de aprendizaje online con el fin de delimitar los parámetros de una enseñanza virtual de calidad.

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We study the probability of perceived racism/other forms of discrimination on immigrant and Spanish populations within different public spheres and show their effect on the health of immigrants using a cross-sectional design (ENS-06). Variables: perceived racism/other forms of discrimination (exposure), socio-demographic (explicative), health indicators (dependent). Frequencies, prevalences, and bivariate/multivariate analysis were conducted separately for men (M) and women (W). We estimated the health problems attributable to racism through the population attributable proportion (PAP). Immigrants perceived more racism than Spaniards in workplace (ORM = 48.1; 95 % CI 28.2–82.2), and receiving health care (ORW = 48.3; 95 % CI 24.7–94.4). Racism and other forms of discrimination were associated with poor mental health (ORM = 5.6; 95 % CI 3.9–8.2; ORW = 7.3; 95 % CI 4.1–13.0) and injury (ORW = 30.6; 95 % CI 13.6–68.7). It is attributed to perceived racism the 80.1 % of consumption of psychotropics (M), and to racism with other forms of discrimination the 52.3 % of cases of injury (W). Racism plays a role as a health determinant.

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Una de las estrategias didácticas digitales que se enmarca dentro de la Web 2.0 corresponde a la WebQuest, caracterizada principalmente por el uso de Internet por parte del alumnado, previo a una cuidadosa selección de enlaces realizada por el profesorado. Esta estrategia digital se sustenta teóricamente en las corrientes constructivistas y el aprendizaje colaborativo, por lo que es plenamente pertinente a los postulados del EEES, a la vez que contribuye a innovar en las prácticas docentes. En este documento se expone la segunda fase de un trabajo que empezó a desarrollarse en el curso 2013-14, y cuyo objetivo principal ha sido el diseño de WebQuests que cumplan con criterios de calidad en el marco de la Enseñanza Superior. En el diseño de estas WebQuests se ha tenido en cuenta la plena accesibilidad del alumnado y la pertinencia a las distintas disciplinas en las que se desempeñan los miembros que conforman esta Red.