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Search Results: 1 - 10 of 36149 matches for " Linares Hernández "
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Trihalomethanes in Comerio Drinking Water and Their Reduction by Nanostructured Materials  [PDF]
Jorge Hernández Bourdon, Francisco Márquez Linares
Soft Nanoscience Letters (SNL) , 2014, DOI: 10.4236/snl.2014.42005
Abstract: The formation of disinfection by-products (DBPs) during chlorination of drinking water is an issue which has drawn significant scientific attention due to the possible adverse effects that these compounds have on human health and the formation of another DBPs. Factors that affect the formation of DBPs include: chlorine dose and residue, contact time, temperature, pH and natural organic matter (NOM). The most frequently detected DBPs in drinking water are trihalomethanes (THMs) and haloacetic acids (HAAs). The MCLs are standards established by the United States Environmental Protection Agency (USEPA) for drinking water quality established in Stage 1, Disinfectants and Disinfection Byproducts Rule (DBPR), and they limit the amount of potentially hazardous substances that are allowed in drinking water. The water quality data for THMs were evaluated in the Puerto Rico Aqueduct and Sewer Authority (PRASA). During this evaluation, the THMs exceeded the maximum contamination limit (MCLs) for the Comerio Water Treatment Plant (CWTP). USEPA classified the THMs as Group B2 carcinogens (shown to cause cancer in laboratory animals). This research evaluated the THMs concentrations in the following sampling sites: CWTP, Río Hondo and Pinas Abajo schools, Comerio Health Center (CDT), and the Vázquez Ortiz family, in the municipality of Comerio Puerto Rcio. The results show that the factors affecting the formation of THMs occur in different concentrations across the distribution line. There are not specific ranges to determine the formation of THMs in drinking water when the chemical and physical parameters were evaluated. Three different nanostructured materials (graphene, mordenite (MOR) and multiwalled carbon nanotubes (MWCNTs)) were used in this research, to reduce the THMs formation by adsorption in specific contact times. The results showed that graphene is the best nanomaterial to reduce THMs in drinking water. Graphene can reduce 80 parts per billion (ppb) of THMs in about 2 hours. In addition mordenite can reduce approximately 80 ppb of THMs and MWCNTs adsorbs 71 ppb of THMs in the same period of time respectively. In order to complement the adsorption results previously obtained, total organic carbon (TOC) analyses were measured, after different contact times with the nanomaterials. During the first 30 minutes, graphene C/Co was reduced to c.a. 0.9, in presence of each THMs solution. MWCNTs and MOR show similar adsorptions trends in comparison with graphene.
New High-Performance Full Adders Using an Alternative Logic Structure
Linares Aranda, Mónico;Aguirre Hernández, Mariano;
Computación y Sistemas , 2011,
Abstract: this paper presents two new high-speed low-power 1-bit full-adder cells using an alternative logic structure, and the logic styles dpl and sr-cpl. the adders were designed using electrical parameters of a 0.35μm complementary metal-oxide-semiconductor (cmos) process, and were compared with various adders published previously, with regards of power-delay product. to validate the performance simulation results of one of the proposed adders, an 8-bits pipelined multiplier was fabricated using a 0.35μm cmos technology, and it showed to provide superior performance.
Enfermedad de Kikuchi-Fujimoto: Presentación de un caso pediátrico
Hernández Cabezas,Ania; Díaz Linares,Nelkis C;
Revista Cubana de Hematolog?-a, Inmunolog?-a y Hemoterapia , 2010,
Abstract: this is the case of a white patient aged 14 diagnosed with kikuchi-fujimoto disease presenting adenopathies prevailing in left cervical region, short-term course fever and involvement of its general condition without weigh loss. authors made studies of general hematology, viral serology and fine needle aspiration biopsy of a cervical ganglion. there were suspicions of neoplasic cells in aspirate. ganglion biopsy showed abundant histiocytes, immunoblasts, and cellular necrosis with nuclear powder and caryorrhesis, as well as a lack of neutrophils and eosinophils. there was a favorable course with disappearance of fever at 20 days from the onset of its manifestations with a gradual regression of adenopathies.
A noise tolerant technique for submicron dynamic digital circuits
Mendoza-Hernández, F;Linares-Aranda, M;
Revista mexicana de física , 2007,
Abstract: signal integrity issues are a main concern in high performance circuits due to technological advancement. the smaller size of the cmos transistors together with the increasing use of dynamic logic has brought signal integrity issues to the forefront. hence it is necessary to develop noise-tolerant circuit techniques that will tolerate noise effects with slight performance penalties. in this paper a new noise tolerant dynamic digital circuit technique is proposed and demonstrated. simulation results for cmos and gate show that the proposed technique has an improvement in the ante metric of 3.4x over conventional dynamic logic. a one-bit carry look-ahead adder implemented with the proposed technique has been designed and fabricated using an ams 0.35 μm cmos n-well process. the experimental results show the noise immunity improvements of ante by 2.1x over the conventional dynamic circuit.
Análisis de las poblaciones de briófitos y líquenes en el gradiente altitudinal de una carretera en Cundinamarca, Colombia
Hernández Vanegas María Ximena,Linares édgar L.
Acta Biológica Colombiana , 2006,
Abstract: En una carretera, a lo largo de un gradiente altitudinal, en Cundinamarca, Colombia, se estudiaron musgos asociados a sustratos de concreto, encontrando dos tipos de zonación, una asociada a ambientes generados por el borde de la carretera “Zonación Transversal”; y otra, “Zonación Altitudinal”, relacionada con el gradiente altitudinal. Diagramas de zonación fueron construidos a partir de datos de presencia, analizados con el índice de Similaridad de Sorensen y a partir de datos de porcentaje de cobertura por especie. En ambos casos se observó, que el establecimiento de musgos está determinado por la humedad, la cual depende de la porosidad del concreto, microtopografía, ángulo de inclinación, sombra y altitud.
Enfermedad de Kikuchi-Fujimoto: Presentación de un caso pediátrico Kikuchi-Fujimoto disease: Presentation of a pediatric case
Ania Hernández Cabezas,Nelkis C Díaz Linares
Revista Cubana de Hematolog?-a, Inmunolog?-a y Hemoterapia , 2010,
Abstract: Se comunica un paciente masculino de 14 a os, blanco, con diagnóstico de enfermedad de Kikuchi-Fujimoto, que presentaba adenopatías predominantemente en región cervical izquierda, fiebre de corto tiempo de evolución y compromiso del estado general sin pérdida de peso. Se hicieron estudios de hematología general, serología viral y biopsia por aspiración con aguja fina de un ganglio cervical. El aspirado fue sospechoso de células neoplásicas. La biopsia ganglionar mostró abundantes histiocitos, inmunoblasblos, necrosis celular con polvo nuclear y cariorrexis, así como ausencia de neutrófilos y eosinófilos. Evolucionó favorablemente con desaparición de la fiebre a los 20 días del inicio de sus manifestaciones con regresión paulatina de las adenopatías. This is the case of a white patient aged 14 diagnosed with Kikuchi-Fujimoto disease presenting adenopathies prevailing in left cervical region, short-term course fever and involvement of its general condition without weigh loss. Authors made studies of general hematology, viral serology and fine needle aspiration biopsy of a cervical ganglion. There were suspicions of neoplasic cells in aspirate. Ganglion biopsy showed abundant histiocytes, immunoblasts, and cellular necrosis with nuclear powder and caryorrhesis, as well as a lack of neutrophils and eosinophils. There was a favorable course with disappearance of fever at 20 days from the onset of its manifestations with a gradual regression of adenopathies.
A noise tolerant technique for submicron dynamic digital circuits
F. Mendoza-Hernández,M. Linares-Aranda
Revista mexicana de física , 2007,
Abstract: Los avances de la tecnología de circuitos integrados CMOS de muy alta escala de integración VLSI (Very-Large Scale Integration) han permitido obtener microprocesadores rápidos y de bajo consumo de potencia aplicables a sistemas portátiles, inalámbricos y multimedia. La obtención de estos microprocesadores ha sido posible gracias al escalamiento de las dimensiones de los transistores y de sus interconexiones. Sin embargo, cuando los circuitos integrados se reducen (escalan), el ruido de acoplamiento entre las interconexiones degrada el desempe o de los sistemas. Debido a esto, es necesario desarrollar técnicas de tolerancia a ruido que reduzcan los efectos del ruido con mínima degradación de desempe o de los circuitos y sistemas. En este artículo se propone una nueva técnica de tolerancia al ruido de acoplamiento. Los resultados muestran que esta técnica mejora la robustez de los circuitos comparada con la obtenida con otras técnicas recientemente publicadas y consideradas de alta tolerancia al ruido de acoplamiento. La efectividad de la técnica propuesta es verificada mediante resultados experimentales obtenidos de un circuito sumador completo dise ado y fabricado utilizando una tecnología CMOS AMS de 0.35 μm.
Zinc and Lead Biosorption by Delftia tsuruhatensis: A Bacterial Strain Resistant to Metals Isolated from Mine Tailings  [PDF]
Dorian A. Bautista-Hernández, Landy I. Ramírez-Burgos, Enrique Duran-Páramo, Luis Fernández-Linares
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.44023
Abstract: A bacterial strain capable of Zinc and Lead biosorption was isolated from mine tailings. This strain showed the highest minimum inhibitory concentrations (MIC) of metals among other isolates in metal-resistance tests. Sorption tests were conducted placing 0.015 g of dry biomass in 10 ml of metallic solution at fixed pH. Contact was analyzed at different times (kinetics) and different initial concentrations (isotherm). The biomass was separated by centrifugation and the concentration of non-absorbed metal was determined using atomic absorption spectroscopy. The strain was identified by 16S sequencing as Delftia tsuruhatensis. The order of toxicity of the metals to the bacterium was Zn > Pb > Se > Ni > Cu = Al. Zinc and Lead absorption kinetics were adjusted to the pseudo second order equation (r2 = 0.99), showing that equilibrium was reached at 40 and 20 min, respectively. Maximal absorption of Pb and Zn was 0.216 and 0.207 mmol?g–1, respectively; which can be considered a median magnitude capacity when compared to other biosorbents described in the literature.
Estudio preliminar de vigilancia y pronóstico para sigatoka negra (Mycosphaerella fijiensis Morelet) en el cultivo de plátano (Musa AAB cv Hartón) en Macagua-Jurimiquire, estado Yaracuy
Hernández G.,L; Hidalgo,W; Linares,B; Hernández,J; Romero,N; Fernandez,S;
Revista de la Facultad de Agronomía , 2005,
Abstract: to establish a survey and forecast program for black sigatoka disease in musa aab cv harton plantain stablished on growing in small production system. the severity average index (sai), youngest spotted leaf position (yslp), foliar emission (fe), daily precipitation (pp), relative humidity (rh), evaporation (eva), maximun and minimun temperature (tmax and tmin), cloudiness (cl), insolation and radiation were determined every 2 weeks. the averages per month for some of these climatic variables were: pp 143.5 mm; tmax 29°c; tmin 21°c and rh 78.5%. the sai was correlated to the climatic variables during 8-consecutive weeks, previous to evaluate the disease severity. the variable with the best correlated coeficients were analized by using multiple regression method. the higher values of sai were observed in january 1.31; may 1.14; september 1.32; october 1.20 and december 1.21 during this study. the yslp average was 5.38 with a maximun of 6.88 and minimum of 4.40; while the sai average was 1.13 with a minimum of 0.64 and a maximum of 1.32. a negative correlation were observed between sai and yslp (r = - 0.7132), and between sai and fe (r = - 0.2556). the disease behavior is 33,32% explained by the following equation: sai = 3.7241** - 0.0047**cl 0.0015**tmin + 2.019**rh 0.0051**eva, according to acumulated values during 6-consecutive weeks previous to the last week of sai observation.
Capacidad predictiva del corte de la décima semana en el rendimiento docente de la asignatura fisiología Predictive capacity of the Academic cutting in 10th week. Teaching Profit in Physiology subject
Yunit Hernández Rodríguez,Ernesto Cruz Menor,Miriam Guerra Paredes,Lucía Linares Hernández
Revista de Ciencias M??dicas de Pinar del R?-o , 2007,
Abstract: Introducción: Se dispone de escasos indicadores predictores del rendimiento académico en la asignatura Fisiología. Objetivos: Evaluar la capacidad predictiva del corte de la décima semana respecto a los resultados de examen final ordinario en la asignatura de Fisiología de la carrera de Medicina. Materiales y Métodos: Se estudiaron los resultados del corte y la nota del examen final ordinario de 1250 estudiantes que recibieron la asignatura en los últimos 5 semestres que se han impartido hasta este curso 2006-2007 en la Facultad de Ciencias Médicas de Pinar del Río "Dr. Ernesto Guevara de la Serna". Para variables cualitativas se utilizaron el cálculo de porcentajes y números absolutos. La concordancia entre las evaluaciones se evaluó mediante el índice Kappa al 95 % de certeza. Además se realiza Chi cuadrado para evaluar capacidad predictiva. Resultados: Existió correspondencia de los resultados del corte con los resultados del examen final ordinario con significación leve en cuanto a la asociación cuando se usa como predictor de éxito-fracaso. Se constataron diferencias en el comportamiento por semestres y cursos escolares. Conclusiones: El corte de la décima semana constituye un indicador que aproximadamente es capaz de predecir el rendimiento académico de los alumnos en la asignatura Fisiología y que es mejor predictor cuando existen mayor número de estudiantes evaluados dentro de cada categoría. Introduction: Predictive indicators of the academic profit in Physiology subject are scarce. Objectives: To assess the predictive capacity of the academic cutting in the 10th week in relation to the results of the final examination of Physiology subject in medical major. Material and methods: Results of the academic cutting and the final examination marks of 1250 students receiving the subject in the last five semesters till course 2006-2007 were collected at "Ernesto Guevara del Serna" Medical School in Pinar del Rio. Qualitative variates were used to calculate the percentages and absolute numbers. The coincidence in evaluations was assessed using Kappa index with a 95% of certainty. Results: A correspondence with the results of the academic cutting and the results of the final examination was observed having a slight significance regarding the association when using failure-success as a predictor. Differences in the behavior per semesters and the academic courses were noted. Conclusions: The academic cutting in the tenth week constitutes an indicator to predict the academic profit of the students in Physiology subject and this was the best predictor to be
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