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Search Results: 1 - 10 of 4609 matches for " Raul Fuentes-Azcatl "
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Thermodynamic and dynamic anomalous behavior in the TIP4P/ε water model
Raul Fuentes-Azcatl,Marcia C. Barbosa
Physics , 2015,
Abstract: The model Tip4p/{\epsilon} for water is tested for the presence of thermodynamic and dy- namic anomalies. Molecular dynamic simulations for this model were performed and we show that for this system the density versus temperature at constant pressure ex- hibits a maximum. In addition we also show that the diffusion coefficient versus density at constant temperature has a maximum and a minimum. The anomalous behavior of the density and of the diffusion coefficient obey the water hierachy. The results for the Tip4p- are consistent with experiments and when compared with the Tip4p-2005 model show similar results a variety of physical properties and better performance for the dielectric constant.
Sodium Chloride, NaCl/ε : New Force Field
Raul Fuentes-Azcatl,Marcia C. Barbosa
Physics , 2015,
Abstract: A new computational model for Sodium Chloride, the NaCl/{\epsilon}, is proposed. The Force Fields employed here for the description of the NaCl is based on a set of radial particle-particle pair potentials involving Lennard-Jones (LJ) and Coulombic forces. The parameterization is obtained fitting the density of the crystal and the density and the dielectric constant of the mixture of salt with water at diluted solution. Our model shows good agreement with the experimental values for the density and surface tension for the pure system and for the density, the viscosity, the diffusion, and the dielectric constant for the mixture with water at various molal concentrations. The NaCl/{\epsilon} together with the water TIP4P/{\epsilon} model provide a good approximation for studying electrolyte solutions.
ELECTRICAL CONDUCTIVITY OF HYDROPHOBICALLY MODIFIED POLYELECTROLYTES IN METHANOL/WATER SOLUTION
BARRAZA,RAUL G.; OLEA,ANDRES F.; FUENTES,IRMA; MARTINEZ,FRANCISCO;
Journal of the Chilean Chemical Society , 2003, DOI: 10.4067/S0717-97072003000100012
Abstract: measurements of the electrical equivalent conductivity of potassium salts of poly(maleic acid-co-1-olefins), pa-nk2 with n = 12, 18 has been carried out in methanol-water mixtures in the whole range of composition. the relative interaction parameter f*, was determined as a function of the mole fraction of methanol. the values of f* do not follow the same tendency of the limiting equivalent conductivity. this unusual behavior was rationalized in terms of a methanol-induced conformational transition that takes the polymer chain from a compact to an expanded structure. as a consequence of this transition the average charge distance in the polyion increases with increasing mole fraction of methanol. this brings about a decrease of the linear charge density parameter, and therefore an increase of the fraction of polymer charges dissociated from their counterions. the existence of the conformational transition of the pa-nk2 copolymers was confirmed through fluorescence probing experiments
La coloración fluorescente con naranja de acridina y el PAP: validación de ambas técnicas para la detección de Trichomonas vaginalis FLUORESCENT STAINING WITH ACRIDINE ORANGE AND PAP SMEAR: VALIDATION TESTS OF BOTH TECNIQUES FOR THE DETECTION OF Trichomonas vaginalis
SIXTO RAUL COSTAMAGNA,MARIA PRADO FIGUEROA,OSCAR SORIA,ALEJANDRO FUENTES
Parasitología al día , 2000,
Abstract: Se efectuó la validación de la coloración de Papanicolaou, utilizada para citología vaginal, frente a la coloración fluorescente con naranja de acridina, a fin de evaluar el valor de un resultado negativo para Trichomonas vaginalis obtenido en un PAP. Se estudiaron 80 muestras de flujo vaginal de mujeres entre 18 y 45 a os, pacientes de consultorios externos de Ginecología del Hospital Municipal de la ciudad de Bahía Blanca, Provincia de Buenos Aires (Argentina). Las muestras se colorearon paralelamente por la técnica de Papanicolaou y por la coloración fluorescente con naranja de acridina. Los resultados mostraron que el PAP presenta una sensibilidad del 54,5% para la detección de T. vaginalis, validación efectuada frente a la coloración fluorescente con naranja de acridina, para una prevalencia de enfermedad en el grupo de mujeres estudiadas del 13,75% y un nivel de confianza del 95%. Para ensayos "en paralelo" con ambas coloraciones, el valor global de la prueba fue del 93,8%, con un valor predictivo del resultado negativo del 93,2%. Concluimos que si bien T. vaginalis es detectada en el PAP, éste no presenta sensibilidad significativamente elevada como para ser considerada como única prueba, debiéndose complementar siempre con una coloración fluorescente con naranja de acridina, u otra prueba de similar valor The present study examined the validity of PAP staining, as used for vaginal cytology, against fluorescent staining with acridine orange in order to determine the value of a negative result of Trichomonas vaginalis obtained by a PAP smear. We examined eighty vaginal-secretion samples from 18- to 45-year-old female patients of the Hospital Municipal of the city of Bahía Blanca, Province of Buenos Aires, Argentina. The samples were stained in parallel by the PAP smear technique and the fluorescent staining technique with acridine orange described by Fripp in 1975. The results of our validation tests demonstrated that, against fluorescent staining with acridine orange, the PAP smear has a 54.5% sensitivity for the detection of T. vaginalis for a 13.75% prevalence of disease among the females in the study with a 95% confidence level. In assays conducted "in parallel" for both stainings, the global value of the test was 93.8%, with a predictive negative value of 93.2%. We conclude that, although the PAP smear can detect T. vaginalis, its sensitivity is not high enough for the test to be used as the sole diagnostic means and the test must always be supplemented with fluorescent staining with acridine orange or another test of similar value. Otherwise
ELECTRICAL CONDUCTIVITY OF HYDROPHOBICALLY MODIFIED POLYELECTROLYTES IN METHANOL/WATER SOLUTION
RAUL G. BARRAZA,ANDRES F. OLEA,IRMA FUENTES,FRANCISCO MARTINEZ
Journal of the Chilean Chemical Society , 2003,
Abstract: Measurements of the electrical equivalent conductivity of potassium salts of poly(maleic acid-co-1-olefins), PA-nK2 with n = 12, 18 has been carried out in methanol-water mixtures in the whole range of composition. The relative interaction parameter f*, was determined as a function of the mole fraction of methanol. The values of f* do not follow the same tendency of the limiting equivalent conductivity. This unusual behavior was rationalized in terms of a methanol-induced conformational transition that takes the polymer chain from a compact to an expanded structure. As a consequence of this transition the average charge distance in the polyion increases with increasing mole fraction of methanol. This brings about a decrease of the linear charge density parameter, and therefore an increase of the fraction of polymer charges dissociated from their counterions. The existence of the conformational transition of the PA-nK2 copolymers was confirmed through fluorescence probing experiments
La coloración fluorescente con naranja de acridina y el PAP: validación de ambas técnicas para la detección de Trichomonas vaginalis
COSTAMAGNA,SIXTO RAUL; PRADO FIGUEROA,MARIA; SORIA,OSCAR; FUENTES,ALEJANDRO; FERREYRA,RICARDO;
Parasitología al día , 2000, DOI: 10.4067/S0716-07202000000300008
Abstract: the present study examined the validity of pap staining, as used for vaginal cytology, against fluorescent staining with acridine orange in order to determine the value of a negative result of trichomonas vaginalis obtained by a pap smear. we examined eighty vaginal-secretion samples from 18- to 45-year-old female patients of the hospital municipal of the city of bahía blanca, province of buenos aires, argentina. the samples were stained in parallel by the pap smear technique and the fluorescent staining technique with acridine orange described by fripp in 1975. the results of our validation tests demonstrated that, against fluorescent staining with acridine orange, the pap smear has a 54.5% sensitivity for the detection of t. vaginalis for a 13.75% prevalence of disease among the females in the study with a 95% confidence level. in assays conducted "in parallel" for both stainings, the global value of the test was 93.8%, with a predictive negative value of 93.2%. we conclude that, although the pap smear can detect t. vaginalis, its sensitivity is not high enough for the test to be used as the sole diagnostic means and the test must always be supplemented with fluorescent staining with acridine orange or another test of similar value. otherwise, the diagnostic sensitivity would not be any higher than that of vaginal discharge exams in vitro.
Designing a Nano Infrastructure for Brazil’s Amazon Water Resources: A Quadruple Helix Approach  [PDF]
Raul Gouvea
Journal of Water Resource and Protection (JWARP) , 2015, DOI: 10.4236/jwarp.2015.71005
Abstract: This paper elaborates on the role of green technologies and innovations in “greening” Brazil’s Amazon region fresh water resources. The paper elaborates on the development of an innovation quadruple helix to better manage the region’s water resources. Brazil accounts for close to 12% of the earth’s fresh water reserves, while most of it is in the Amazon region. The preservation of water reserves on a global scale is of paramount importance in the 21st century. Brazil, however, has not managed its water resources effectively leading to the increasing pollution and contamination of its Amazonian water resources.
Malaria resurgence risk in southern Europe: climate assessment in an historically endemic area of rice fields at the Mediterranean shore of Spain
Sandra Sainz-Elipe, Jose Latorre, Raul Escosa, Montserrat Masià, Marius Fuentes, Santiago Mas-Coma, Maria Bargues
Malaria Journal , 2010, DOI: 10.1186/1475-2875-9-221
Abstract: The transmission risk was assessed analysing: 1) climate diagrams including the minimum temperature for Plasmodium falciparum and Plasmodium vivax development; 2) monthly evolution of the Gradient Model Risk (GMR) index, specifying transmission risk period and number of potential Plasmodium generations; 3) ecological characteristics using remote sensing images with the Eurasia Land Cover characteristics database and the monthly evolution of the Normalized Difference Vegetation Index (NDVI); 4) evaluation of A. atroparvus population dynamics.Climatological analyses and GMR index show that a transmission risk presently exists, lasting from May until September for P. falciparum, and from May until October for P. vivax. The GMR index shows that the temperature increase does not actually mean a transmission risk increase if accompanied by a precipitation decrease reducing the number of parasite generations and transmission period. Nevertheless, this limitation is offset by the artificial flooding of the rice fields. Maximum NDVI values and A. atroparvus maximum abundance correspond to months with maximum growth of the rice fields.The Ebro Delta presents the ecological characteristics that favour transmission. The temperature increase has favoured a widening of the monthly potential transmission window with respect to when malaria was endemic. The combined application of modified climate diagrams and GMR index, together with spatial characterization conforms a useful tool for assessing potential areas at risk of malaria resurgence. NDVI is a good marker when dealing with a rice field area.Change of climate factors and other variables related to environmental modifications included within the broad term of global change have a proven impact on the transmission of infectious diseases [1,2], caused by different types of infectious organisms including microparasites (viruses, bacteria, rickettsia and protozoans) and also, as very recently proved, metazoan macroparasites (helm
Genetic variability of Triatoma flavida and Triatoma bruneri (Hemiptera: Reduviidae) by RAPD-PCR technique
Fraga, Jorge;Rodriguez, Jinnay;Fuentes, Omar;Hernández, Yenin;Castex, Mayda;Gonzalez, Raul;Fernández-Calienes, Aymé;
Revista do Instituto de Medicina Tropical de S?o Paulo , 2011, DOI: 10.1590/S0036-46652011000100004
Abstract: the triatominae (hemiptera:reduviidae) contains the principal and potential chagas disease vectors present in mexico, central america and south america. triatoma flavida and t. bruneri are cuban species. these species are closely related according to morphology and were considered synonyms until 1981, when they were separated on the grounds of external characters of the body and the morphology of male genitalia. the present study seeks to analyze genetic polymorphism of t. flavida and t. bruneri populations using rapd techniques, and to assess the genetic relationship between these species. ten random primers were used to evaluate the genetic variability among species using rapd-pcr. the genetic flow among them was calculated. the dendrogram based on calculated jaccard distances showed two clearly distinguishable clusters which coincided with the studied species. within each species, moderate genetic differentiation (fst 0.05-0.15) and migration rates (n > 1) were found among populations, that reveal gene flow and genetic homogeneity. between species, the fst value showed a high genetic differentiation and the migration rate was insufficient to maintain genetic homogeneity, and confirmed the absence of gene flow between them. our results confirm the genetic variability among t. flavida and t. bruneri species.
Lazy or Greedy? Impact of Xenophobic Beliefs on Natives’ Attitudes towards Redistribution  [PDF]
Raul Magni Berton
Open Journal of Political Science (OJPS) , 2013, DOI: 10.4236/ojps.2013.31005
Abstract:

Several recent accounts have shown that anti-immigrant feeling among citizens seems to reduce the support for the welfare state. As a consequence, the rise of immigration could produce a deep change in industrialized countries’ social security systems. This paper provides evidence that support for redistribution is not decreased by generic xenophobia, but by a specific kind of xenophobic belief. It also shows that some other xenophobic beliefs tend rather to produce a demand for governmental protection programs. Based on a multivariate analysis on individual and contextual French data, findings show that the support for social protection programs is positively related to the fear of competition from immigrants and negatively with the fear that immigrants strain the welfare state. This result can be generalized to other countries where “redistributive xenophobia” is much more widespread.

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