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Search Results: 1 - 10 of 65874 matches for " Julia; Martínez-Fernández "
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Liver abscess mimicking colon cancer Absceso hepático simulando una neoplasia colónica
Cristina Jimeno-Ayllón,Raquel Martínez-Fernández,Lorena Serrano-Sánchez,Carmen Julia Gómez-Ruiz
Revista Espa?ola de Enfermedades Digestivas , 2011,
Abstract:
La diáspora en la frontera: retos y oportunidades para el estudio del Orlando puertorrique o
Luis Martínez-Fernández
Centro Journal , 2010,
Abstract: This essay reviews and analyses the relatively recent but hugely important phenomenon of the Puerto Rican migration to Central Florida, both from the island and from traditional Puerto Rican enclaves such as New York, Philadelphia and Chicago. It proposes the application of a new paradigm for the study of Puerto Rican Central Florida, a demographic and social reality whose context and timing differ sharply from those of other Puerto Rican communities. The proposed paradigm recognizes Central Florida as a social and political frontier for the nearly 300,000 Puerto Ricans living in the region. This essay also questions the generalized idea of Central Florida as a happy, semitropical paradise by explaining the numerous challenges and forms of discrimination faced by the growing Orlando Rican population.
Modelling long-term fire occurrence factors in Spain by accounting for local variations with geographically weighted regression
J. Martínez-Fernández, E. Chuvieco,N. Koutsias
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2013,
Abstract: Humans are responsible for most forest fires in Europe, but anthropogenic factors behind these events are still poorly understood. We tried to identify the driving factors of human-caused fire occurrence in Spain by applying two different statistical approaches. Firstly, assuming stationary processes for the whole country, we created models based on multiple linear regression and binary logistic regression to find factors associated with fire density and fire presence, respectively. Secondly, we used geographically weighted regression (GWR) to better understand and explore the local and regional variations of those factors behind human-caused fire occurrence. The number of human-caused fires occurring within a 25-yr period (1983–2007) was computed for each of the 7638 Spanish mainland municipalities, creating a binary variable (fire/no fire) to develop logistic models, and a continuous variable (fire density) to build standard linear regression models. A total of 383 657 fires were registered in the study dataset. The binary logistic model, which estimates the probability of having/not having a fire, successfully classified 76.4% of the total observations, while the ordinary least squares (OLS) regression model explained 53% of the variation of the fire density patterns (adjusted R2 = 0.53). Both approaches confirmed, in addition to forest and climatic variables, the importance of variables related with agrarian activities, land abandonment, rural population exodus and developmental processes as underlying factors of fire occurrence. For the GWR approach, the explanatory power of the GW linear model for fire density using an adaptive bandwidth increased from 53% to 67%, while for the GW logistic model the correctly classified observations improved only slightly, from 76.4% to 78.4%, but significantly according to the corrected Akaike Information Criterion (AICc), from 3451.19 to 3321.19. The results from GWR indicated a significant spatial variation in the local parameter estimates for all the variables and an important reduction of the autocorrelation in the residuals of the GW linear model. Despite the fitting improvement of local models, GW regression, more than an alternative to "global" or traditional regression modelling, seems to be a valuable complement to explore the non-stationary relationships between the response variable and the explanatory variables. The synergy of global and local modelling provides insights into fire management and policy and helps further our understanding of the fire problem over large areas while at the same time recognizing its local character.
Standard criteria versus Rosemont classification for EUS-diagnosis of chronic pancreatitis
Jimeno-Ayllón,Cristina; Pérez-García,José Ignacio; Gómez-Ruiz,Carmen Julia; García-Cano-Lizcano,Jesús; Morillas-Ari?o,Julia; Martínez-Fernández,Raquel; Serrano-Sánchez,Lorena; Pérez-Sola,ángel;
Revista Espa?ola de Enfermedades Digestivas , 2011, DOI: 10.4321/S1130-01082011001200004
Abstract: aim: to study the possible differences in the final diagnosis of chronic pancreatitis by using standard classification described by wiersema et al. and the new classification proposed recently by rosemont. material and methods: forty-seven patients with the diagnosis of chronic pancreatitis were included in this study. the parenchymal and ductal criteria were studied, the patients were divided in two groups for wiersema criteria: < 4 criteria, non-diagnostic for chronic pancreatitis and ≥ 4 criteria, diagnosis of chronic pancreatitis. the same patients were divided in four groups according to rosemont classification: normal pancreas, indeterminate, suggestive and consistent with chronic pancreatitis. we analyzed these data with chi-square test reported with 95% confidence intervals (ci). results: in patients with chronic pancreatitis the most frequent criteria observed were lobularity in 66% of cases and pancreatic duct dilatation and calcifications in 57.4% of cases each. we found a significant statistical association between the results of both classifications (p < 0.05). the highest association is found in patients with more than 4 standard criteria and definitive diagnostic of chronic pancreatitis according to rosemont classification. in patients who have less than 4 standard criteria the diagnosis is suggestive of chronic pancreatitis by using the rosemont classification in 27.66% (p < 0.05). conclusion: these results show that no significant statistical differences are found for patients with > 4 criteria diagnosis by standard criteria. but 27.66% patients with less than 4 standard criteria would be suggestive according to rosemont classification (p < 0.05). hence, the new classification would be useful in patients with high suspicion of chronic pancreatitis with < 4 standard criteria but with more significance such as parenchymal lithiasis, lobularity or ductal calcifications.
Insights into the role of differential gene expression on the ecological adaptation of the snail Littorina saxatilis
Mónica Martínez-Fernández, Louis Bernatchez, Emilio Rolán-Alvarez, Humberto Quesada
BMC Evolutionary Biology , 2010, DOI: 10.1186/1471-2148-10-356
Abstract: Among the 99 transcripts shared between ecotypes, 12.12% showed significant differential expression. At least 4% of these transcripts still displayed significant differences after correction for multiple tests, highlighting that gene expression can differ considerably between subpopulations adapted to alternative habitats in the face of gene flow. One of the transcripts identified was Cytochrome c Oxidase subunit I (COI). In addition, 6 possible reference genes were validated to normalize and confirm this result using qPCR. α-Tubulin and histone H3.3 showed the more stable expression levels, being therefore chosen as the best option for normalization. The qPCR analysis confirmed a higher COI expression in SU individuals.At least 4% of the transcriptome studied is being differentially expressed between ecotypes living in alternative habitats, even when gene flow is still substantial between ecotypes. We could identify a candidate transcript of such ecotype differentiation: Cytochrome c Oxidase Subunit I (COI), a mitochondrial gene involved in energy metabolism. Quantitative PCR was used to confirm the differences found in COI and its over-expression in the SU ecotype. Interestingly, COI is involved in the oxidative phosphorylation, suggesting an enhanced mitochondrial gene expression (or increased number of mitochondria) to improve energy supply in the ecotype subjected to the strongest wave action.Unravelling processes that underlie population divergence is a crucial step towards elucidating the origin and maintenance of biodiversity [1], and towards understanding the genetic basis of speciation, which is one of the most fundamental goals in evolutionary genetics [2]. However, there is still much to be learned about how divergent populations adapt to different environments under the effect of natural selection, which ultimately may evolve into biological species [3]. The new "omics" technologies, despite being very young, can contribute to this since they have taken
Environmental changes and human work in the region of the Upper Paraná River floodplain: processes and interactions
Tomanik, EA.;Paiola, LM.;Martínez-Fernández, JB.;Fernandes, SL.;
Brazilian Journal of Biology , 2009, DOI: 10.1590/S1519-69842009000300013
Abstract: the environment and society constitute a complex of elements and interactions. thus, an understanding of the processes in which the environment and psychosocial elements are involved may not be gained from knowledge of just one isolated variable. based on such premises, the present paper, which summarizes the results of a series of studies, adopts work relationships as its main focus, but in addition, it has two complementary objectives. one is to present some analyses on the interaction between human actions and the environmental changes that have been taking place in the region of the upper paraná river floodplain and in its boundaries. a secondary aim is to show how those two factors have been changing people's working and living conditions and the identity configuration of some of the human groups that live at that site.
Cetáceos de las aguas costeras del Pacífico norte y sur de Costa Rica
Martínez-Fernández,Damián; Montero-Cordero,Andrea; May-Collado,Laura;
Revista de Biología Tropical , 2011,
Abstract: inshore cetaceans from the north and south pacific coast of costa rica. twenty nine cetacean species occur in costa rican waters but extensive research has been conducted only for three species. the latter shows there is a lack of general and local information about these mammals, even when the country, has shown a remarkable growth in whale watching activities. the increasing use of marine resources in coastal areas has also developed the need to determine the occurrence of cetaceans in areas showing high tourist presence, in order to propose sound conservation measures. in this study, environmental variables were determined and subsequently related to the presence of the species recorded, out of 166 sightings, between 2005 and 2006. the species with highest proportion of sightings were stenella attenuata (68%), followed by megaptera novaeangliae (13%) and tursiops truncatus (10%). the presence of spotted dolphins is related to changes in salinity and water transparency, while that of the humpback whale was related to wave height (beaufort scale) and water temperature. the presence of seven species of cetaceans was confirmed in two coastal areas of the pacific coast of costa rica, from which three are present throughout the year. environmental variables were found related to the presence of at least two species. rev. biol. trop. 59 (1): 283-290. epub 2011 march 01.
Redes de empresas: proposta de uma tipologia para classifica??o aplicada na indústria de ceramica de revestimento
Hoffmann, Valmir Emil;Molina-Morales, F. Xavier;Martínez-Fernández, M. Teresa;
Revista de Administra??o Contemporanea , 2007, DOI: 10.1590/S1415-65552007000500006
Abstract: this article searches a contribution to actualize on firms networking theme existing on academy nowadays. its objective is to propose a classification typology to firm network. this typology comes from bibliographical research and from three clusters studied of ceramic tile industry, two on brazil and one in spain. the proposition links the clusters to four indicators: directionality; localization; formalization and power. methodological proceedings were survey to ceos; and supporting institutions; and bibliographical research. results have shown each network specificity and its distance to more appropriate cluster according to typology. this work showed differences among networks such, in the same industry and country, two networks can be similar and singular at the same time. also, using a network as reference, it was possible analyzing other networks to this one according to its characteristics. this proposition makes a contribution to network classification beyond directionality and formalization axis.
Cetáceos de las aguas costeras del Pacífico norte y sur de Costa Rica
Damián Martínez-Fernández,Andrea Montero-Cordero,Laura May-Collado
Revista de Biología Tropical , 2011,
Abstract: De las 29 especies de cetáceos presentes en Costa Rica, se han realizado investigaciones exhaustivas solamente para tres especies. Lo anterior evidencia la poca información general existente sobre cetáceos, a pesar de que Costa Rica posee un notable crecimiento de actividades de avistamiento. Debido al uso que se está generando en las zonas costeras, cada vez se hace más necesario determinar la ocurrencia de cetáceos en zonas de alta actividad turística, con el fin de proponer medidas de conservación. En el presente estudio, se determinaron variables ambientales que estaban relacionadas con la presencia de especies registradas, a partir de 166 avistamientos entre el 2005 y 2006. Las especies con mayor proporción de avistamientos fueron Stenella attenuata (68%), seguida por Megaptera novaeangliae (13%) y Tursiops truncatus (10%). La presencia del delfín manchado se relaciona con cambios de salinidad y trasparencia del agua, mientras que la de la ballena jorobada estuvo relacionada con el oleaje y la temperatura superficial del agua. Se confirma la presencia de 7 especies de cetáceos en dos zonas costeras del Pacífico de Costa Rica, de las cuales tres están presentes a lo largo del a o. Se encontraron variables ambientales relacionadas con la presencia de al menos dos especies. Inshore cetaceans from the North and South Pacific coast of Costa Rica. Twenty nine cetacean species occur in Costa Rican waters but extensive research has been conducted only for three species. The latter shows there is a lack of general and local information about these mammals, even when the country, has shown a remarkable growth in whale watching activities. The increasing use of marine resources in coastal areas has also developed the need to determine the occurrence of cetaceans in areas showing high tourist presence, in order to propose sound conservation measures. In this study, environmental variables were determined and subsequently related to the presence of the species recorded, out of 166 sightings, between 2005 and 2006. The species with highest proportion of sightings were Stenella attenuata (68%), followed by Megaptera novaeangliae (13%) and Tursiops truncatus (10%). The presence of spotted dolphins is related to changes in salinity and water transparency, while that of the humpback whale was related to wave height (Beaufort scale) and water temperature. The presence of seven species of cetaceans was confirmed in two coastal areas of the Pacific coast of Costa Rica, from which three are present throughout the year. Environmental variables were found related to the p
Hepatotoxicidad por gabapentina Hepatotoxicity by gabapentin
M. Santana,R. Pernas,E. Martínez-Fernández,J. Díaz-Sanguino
Revista de la Sociedad Espa?ola del Dolor , 2004,
Abstract:
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