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Search Results: 1 - 10 of 477682 matches for " Jenaro Acu?a-González "
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Metales traza en sedimentos costeros de Costa Rica
García-Céspedes,Jairo; Acua-González,Jenaro; Vargas-Zamora,José A;
Revista de Biología Tropical , 2004,
Abstract: marine sediment samples from four coastal ecosystems in costa rica were taken between the years 2000-2002 and their iron, lead, copper and zinc concentrations were determined by the atomic absorption technique with flame or graphite furnace. in the pacific coast, culebra bay (papagayo gulf), gulf of nicoya, and golfito bay (dulce gulf), were selected as representative sites, and moín bay, at the caribbean coast. mean metal concentrations for all ecosystems followed the same pattern: fe > zn > cu > pb. no temporal pattern was found for any metal. iron and copper mean concentrations were higher in golfito bay (5.8% and 87 μg / g, respectively) and lower in moín bay (3.4% and 52 μg / g, respectively). zinc mean concentration was also higher in golfito bay (96 μg / g), but lower in culebra bay (66 μg / g). lead mean concentration was higher in moín bay (6.4 μg / g) and lower in culebra bay (3.0 μg / g). lead highest concentrations occurred in the caribbean and in golfito bay, and for the rest of the elements the maximum values were found in golfito bay. on the basis of data obtained in this work, culebra bay was considered a relatively unpolluted location; golfito bay was more contaminated, and moín bay and the gulf of nicoya showed an intermediate condition
Metales traza en sedimentos costeros de Costa Rica
Jairo García-Céspedes,Jenaro Acua-González,José A Vargas-Zamora
Revista de Biología Tropical , 2004,
Abstract: Se determinó la concentración de hierro, plomo, cobre y zinc, en sedimentos de cuatro ecosistemas costeros de Costa Rica, por espectroscopia de absorción atómica, con llama o con horno de grafito. En el Pacífico se escogieron Bahía Culebra (Golfo de Papagayo), el Golfo de Nicoya y la bahía de Golfito (Golfo Dulce) y en el Caribe la bahía de Moín. Las muestras fueron recolectadas entre los a os 2000 y 2002, y los valores promedio de las concentraciones de los elementos, en todos los ecosistemas, siguieron una misma tendencia: Fe > Zn > Cu > Pb. No se encontró ningún tipo de patrón temporal de distribución de los metales en ninguno de los ecosistemas. Las concentraciones medias de hierro y de cobre fueron mayores en la bahía de Golfito (5.8% y 87 μg / g, respectivamente) y menores en la bahía de Moín (3.4% y 52 μg / g. respectivamente). La concentración media de zinc fue mayor también en la bahía de Golfito (96 μg / g), pero menor en Bahía Culebra (66 μg / g). La concentración de plomo fue mayor en la bahía de Moín (6.4 μg / g) y menor en Bahía Culebra (3.0 μg / g). La concentración de plomo fue alta en el Caribe y en la bahía de Golfito; los valores de concentración promedio obtenidos para el hierro, el plomo, el cobre y el zinc, fueron máximos en la bahía de Golfito, comparados con los otros ecosistemas. Con base en los datos obtenidos, se concluyó que la Bahía Culebra fue la zona más limpia; la bahía de Golfito la más contaminada y en un lugar intermedio la bahía de Moín y el Golfo de Nicoya Marine sediment samples from four coastal ecosystems in Costa Rica were taken between the years 2000-2002 and their iron, lead, copper and zinc concentrations were determined by the atomic absorption technique with flame or graphite furnace. In the Pacific coast, Culebra Bay (Papagayo Gulf), Gulf of Nicoya, and Golfito Bay (Dulce Gulf), were selected as representative sites, and Moín Bay, at the Caribbean coast. Mean metal concentrations for all ecosystems followed the same pattern: Fe > Zn > Cu > Pb. No temporal pattern was found for any metal. Iron and copper mean concentrations were higher in Golfito Bay (5.8% and 87 μg / g, respectively) and lower in Moín Bay (3.4% and 52 μg / g, respectively). Zinc mean concentration was also higher in Golfito Bay (96 μg / g), but lower in Culebra Bay (66 μg / g). Lead mean concentration was higher in Moín Bay (6.4 μg / g) and lower in Culebra Bay (3.0 μg / g). Lead highest concentrations occurred in the Caribbean and in Golfito Bay, and for the rest of the elements the maximum values were found in Golfito Bay. On the basis of
Hidrocarburos de petróleo, disueltos y dispersos, en cuatro ambientes costeros de Costa Rica
Acua-González,Jenaro; Vargas-Zamora,José A; Gómez-Ramírez,Eddy; García-Céspedes,Jairo;
Revista de Biología Tropical , 2004,
Abstract: four coastal ecosystems with contrasting characteristics were sampled in costa rica (2000 - 2002). oil pollution status, expressed as the fraction of dissolved/dispersed petroleum hydrocarbons related to chrysene equivalents, was determined by the molecular fluorescence analytical technique. a total of 130 water samples were taken, from the caribbean (moín bay), and from the pacific (bahía culebra, gulf of nicoya and dulce gulf). on one occasion, seven samples along the puntarenas estuary were also analysed. in moín the mean and standard deviation were 0.10 μg·l-1 ± 0.18 μg·l-1 , ranging from non detectable (nd) to 0.65 μg·l-1 . for the pacific ecosystems the total range was from nd to 0.37 μg·l-1 . in bahía culebra no fluorescence signals were obtained. in the gulf of nicoya the mean and standard deviation were 0.04 μg·l-1 ± 0.09 μg·l-1 , from nd to 0.33 μg·l-1 . values in dulce gulf were 0.05 μg·l-1 ± 0.11 μg·l-1 , from nd to 0.37 μg·l-1 . along the puntarenas estuary the range was 0.17 to 5.91 μg·l-1 , with a mean of 1.21 μg·l-1 and a standard deviation of ± 2.10 μg·l-1 . the four coastal ecosystems had concentrations below the 10 μg·l-1 limit for polluted oceanic areas. the puntarenas estuary reflects the influence of antropogenic activities from and around the city of puntarenas. these levels are considered low for inshore waters
Hidrocarburos de petróleo, disueltos y dispersos, en cuatro ambientes costeros de Costa Rica
Jenaro Acua-González,José A Vargas-Zamora,Eddy Gómez-Ramírez,Jairo García-Céspedes
Revista de Biología Tropical , 2004,
Abstract: Entre los a os 2000 a 2002 se recolectaron y se analizaron 130 muestras de agua de mar en las costas de Costa Rica, para determinarles la concentración de hidrocarburos de petróleo disueltos y dispersos (HPDD), referida a equivalentes de criseno en hexano, y expresada como μg·L-1 . Se utilizó la técnica analítica de fluorescencia molecular. 42 muestras correspondieron al Caribe (Moín) y 81 al Pacífico (Bahía Culebra, Golfo de Nicoya, Golfo Dulce y en una ocasión se tomaron muestras a lo largo del Estero de Puntarenas). En la zona costera de Moín el promedio de la concentración de HPDD fue 0.10 μg·L-1 , con una desviación estándar de ± 0.18 μg·L-1 , en un ámbito desde concentraciones no detectables por el método, (nd), hasta 0.65 μg·L-1 . En el Pacífico las concentraciones para todo el período del estudio, estuvieron entre nd y 0.37 μg·L-1 . En la Bahía Culebra no se detectaron HPDD en ninguna de las muestras (n = 12); en el Golfo de Nicoya el promedio y la desviación estándar fueron 0.04 μg·L-1 ± 0.09 μg·L-1 (n = 51), en un ámbito desde nd hasta 0.33 μg·L-1 . En el Golfo Dulce el promedio y la desviación estándar fueron 0.05 μg·L-1 ± 0.11 μg·L-1 (n = 18), en el ámbito desde nd a 0.37 μg·L-1 . Durante las fechas en que se llevó a cabo el muestreo, no se encontró una situación de contaminación por petróleo en los ecosistemas costeros estudiados, puesto que las concentraciones de HPDD no rebasaron el límite de 10 μg·L-1 referido a equivalentes de criseno, considerado típico de áreas oceánicas contaminadas. En Bahía Culebra fue la primera vez que se hizo el estudio de la contaminación por petróleo y se comprobó que en las fechas de muestreo la zona estuvo libre de esta contaminación. El promedio y la desviación estándar en el Estero de Puntarenas fueron 1.21 μg·L-1 ± 2.10 μg·L-1 (n = 7), en un ámbito de 0.17 a 5.91 μg·L-1 . Estos resultados evidenciaron una situación de contaminación moderada y la naturaleza estuarina de este cuerpo de agua costera, que distribuye irregularmente los HPDD descargados en ella Four coastal ecosystems with contrasting characteristics were sampled in Costa Rica (2000 - 2002). Oil pollution status, expressed as the fraction of dissolved/dispersed petroleum hydrocarbons related to chrysene equivalents, was determined by the molecular fluorescence analytical technique. A total of 130 water samples were taken, from the Caribbean (Moín Bay), and from the Pacific (Bahía Culebra, Gulf of Nicoya and Dulce Gulf). On one occasion, seven samples along the Puntarenas estuary were also analysed. In Moín the mean and standard deviation were 0
Family history and socioeconomic risk factors for non-syndromic cleft lip and palate: A matched case-control study in a less developed country Factores de riesgo hereditarios y socioeconómicos para labio o paladar hendido no asociados a un síndrome en México: estudio de casos y controles pareado
Gladys Acua-González,Carlo E. Medina-Solís,Gerardo Maupomé,Mauricio Escoffie-Ramírez
Biomédica , 2011,
Abstract: Introduction. From an epidemiological point of view, non-syndromic orofacial clefts are the most common oral congenital deformities worldwide. Objective. Family histories were traced and socioeconomic risk factors were identified for non-syndromic cleft lip with or without cleft palate. Material and methods. A case-control study was carried out with 208 cases of non-syndromic cleft lip with or without cleft palate, and matched by age and sex with 416 controls. Cases were patients attending a referral clinic from 2002 through 2004 in Campeche, Mexico. A questionnaire was administered to collect sociodemographic and socioeconomic variables as well as familial background relevant to non-syndromic cleft lip with or without cleft palate. Conditional logistic regression models were used; adjusted odds ratios and 95% confidence intervals were calculated. Results. In the multivariate model, the following risk factors were identified: 1) low socioeconomic status; 2) birth in the southern region of Campeche state; 3) home delivery or delivery in a publicly funded hospital; 4) occurrence of prior non-syndromic cleft lip with or without cleft palate cases in the father's or mother's family: 5) having a sibling with non-syndromic cleft lip with or without cleft palate; 6) the proband having another malformation, and 7) a history of infections during pregnancy. Prenatal care consisting of vitamin supplementation was a protective factor for non-syndromic cleft lip with or without cleft palate (odds ratio=0.29). Conclusions. A "social gradient in health" was seen to link oral malformation with diet components, and several socioeconomic and socio-demographic factors broadly encompassed in low socioeconomic status. Further characterization of risk factors will guide the assemblage of a pro-active counseling and prevention program for families at risk for non-syndromic cleft lip and cleft palate. Introducción. Desde el punto de vista epidemiológico, las hendiduras faciales son las deformidades orales más comunes alrededor del mundo. Objetivo. Identificar los factores de riesgo hereditarios y socioeconómicos relacionados con la presencia de labio o paladar hendido no asociados a un síndrome. Materiales y métodos. Se hizo un estudio de casos y controles en el que se incluyeron 208 casos con diagnóstico de labio, paladar hendido o ambos no asociados a un síndrome, los cuales fueron pareados por edad y sexo con 416 controles. Se incluyeron todos los pacientes quirúrgicos atendidos durante el periodo 2002-2004 en el programa estatal de labio o paladar hendido de Campeche, Méxic
Posesión, retención y uso de mosquiteros tratados con insecticidas de larga duración luego de un a?o de su distribución en Loreto, Perú
Rosas-Aguirre,Angel; Guzmán-Guzmán,Mitchel; Moreno-Gutierrez,Diamantina; Rodriguez-Ferrucci,Hugo; Vargas-Pacherrez,Daniel; Acua-González,Ysabel;
Revista Peruana de Medicina Experimental y Salud Pública , 2011, DOI: 10.1590/S1726-46342011000200009
Abstract: objectives. to assess long-lasting insecticide - treated bednet (llitn) ownership, retention and usage one year after their distribution in loreto, peru. materials and methods. from july to september 2007, 26,185 llitns olyset net ? were delivered in 194 targeted communities in the peruvian amazon region, covering 45,331 people. two cross-sectional community-based surveys in december 2007 and july 2008 were undertaken in a sample of 60 targeted communities (30.9% out of the total). a semi-structured questionnaire was used to collect necessary data to calculate llitn ownership, retention and usage indicators. results. high llitn household ownership was showed in both surveys (99.9% and 98.7%, respectively). llitn/ person ratio decreased from 0.58 at the end of the llitn delivery to 0.51 in the second survey, estimating llitn retention of 87% after 1 year of intervention. in the first survey, 99.0% of all children <5 years and 96,0% of pregnant women slept under a llitn the previous night, while in the second survey, 77.7% of children <5 years and 66.3% of pregnant women slept under a llitn the previous night. big mesh size of llitn had low people′s acceptability, reaching only 39.0% in the second survey. conclusions. although universal llitn household ownership remained high, their llitn usage levels have decreased during one-year follow-up period.
The relative nature of fertilization success: Implications for the study of post-copulatory sexual selection
Francisco García-González
BMC Evolutionary Biology , 2008, DOI: 10.1186/1471-2148-8-140
Abstract: Fertilization success values render biased sperm competitive ability values. Furthermore, asymmetries among males in the errors committed when estimating sperm competitive abilities are likely to exist as long as males exhibit variation in sperm competitiveness. Critically, random effects arising from the relative nature of fertilization success lead to an underestimation of underlying additive genetic variance in sperm competitive ability.The results show that, regardless of the existence of genotypic interactions affecting the output of sperm competition, fertilization success is not a perfect predictor of sperm competitive ability because of the stochasticity of the background used to obtain fertilization success measures. Random effects need to be considered in the debate over the maintenance of genetic variation in sperm competitiveness, and when testing good-genes and compatible-genes processes as explanations of polyandrous behaviour using repeatability/heritability data in sperm competitive ability. These findings support the notion that the genetic incompatibility hypothesis needs to be treated as an alternative hypothesis, rather than a null hypothesis, in studies that fail to detect intrinsic sire effects on the sperm competitiveness phenotype.A wealth of research inspired by Parker's [1] seminal study on sperm competition has provided overwhelming evidence that mating success is not always equivalent to reproductive success [1-4]. Sperm competition, a direct consequence of polyandry (females mating with different partners within a single reproductive episode), can contribute to the maintenance of promiscuity if females accrue benefits from encouraging the overlap of ejaculates at the site of fertilization. The sexy-sperm hypothesis, a post-copulatory analogue of the sexy-sons model for the evolution of female preferences and male attractiveness [5-7], suggests that polyandrous females could enhance their fitness if fertilization success is genetically co
Acción vaso-periférica del extracto acuoso de las hojas de Clusia coclensis (Clusiaceae)
García-González,Mildred;
Revista de Biología Tropical , 1998,
Abstract: aqueous leaf extract of clusia coclensis was applied at a dose of 40 mg/kg intravenously to isolated posterior extremities of six normotensive sprague-dawley rats and six spontaneously hipertensive rats anaesthetized with sodium nembutal. the perfusion was done in the abdominal artery using as carrier krebs bicarbonate ringer at 37 °c and keeping constant perfusion pressures of 100 mmhg in normotensive rats and 150 mmhg in hipertensive ratas. the venous return was measured in the inferior vena cava. the extract induced a significant reduction of the venous return begining 2 min after application, in both rat types. this may reflect a peripheral vasoconstriction that, in whole organism,would have an hipertensive effect. therefore, the mechanism of the alledgedly systemic hipotensive effect of the aqueous extract of clusia coclensis leafs resides probably at a central level, probably acting by a reduction of the contractibility of the myocardium.
Elementos para una filogeografía de la cabra montés ibérica (Capra pyrenaica schinz, 1838)
García-González, Ricardo
Pirineos : Revista de Ecología de Monta?a , 2011,
Abstract: In order to provide some issues for a future study of Capra pyrenaica phylogeography I review classic and recent works considering data of genetic studies known to date, as well as recent findings related to paleontology and biometrics. C. pyrenaica has experienced several population bottlenecks throughout its history that have led to a loss of genetic diversity. In addition, numerous recent translocations and population reinforcements can complicate the clarification of intraspecific genetic differentiation. I review current theories about the evolution of the species. One of them establishes a recent evolution (past 18,000 years) from ancestors related to C. caucasica. I analyze in some detail the morphological characters (mainly teeth and horns) on which this theory is based, showing their high variability. Present genetic studies show a clear relationship between C. pyrenaica and Alpine ibex (C. i. ibex). They also show a north-south genetic differentiation between Iberian goats, occupying the Pyrenean goats (C. p. pyrenaica) an intermediate position between Alpine ibex and southern Iberian goats. Recent paleontological findings evidence an ancient presence (Lower Pleistocene) of Capra in the Iberian Peninsula. I propose the hypothesis that the descendants of these ancient goats, may have come into contact with C. ibex in the Pyrenees and southern France, one or more times during the Upper Pleistocene. Intermediate characteristics, both genetic and biometric, of the extinct Pyrenean goats, would agree with this hypothesis. New paleontological records and more genetic studies (including fossil and recent materials) are necessary, to elucidate both the phylogeny of C. pyrenaica and its intraspecific diversification. En este trabajo se realiza una revisión sintética de los trabajos clásicos y recientes que conciernen a la filogeografía de Capra pyrenaica, aportando datos de los estudios genéticos conocidos hasta la fecha, así como de nuevos hallazgos relativos a su paleontología y biometría. C. pyrenaica ha experimentado varios cuellos de botella poblacionales a lo largo de su historia que han producido pérdida de diversidad genética. Al mismo tiempo, numerosas traslocaciones y reforzamientos poblacionales pueden complicar la clarificación de su diferenciación genética a nivel intraespecífico. Se revisan algunas teorías actuales sobre la evolución de la especie, que contemplan su evolución reciente (últimos 18.000 a os) a partir de ancestros afines a C. caucasica. Se examinan con cierto detalle los caracteres morfológicos en los que se basa dicha teoría
Acción vaso-periférica del extracto acuoso de las hojas de Clusia coclensis (Clusiaceae)
Mildred García-González
Revista de Biología Tropical , 1998,
Abstract: Se inyectó extracto acuoso de hojas de Clusia coclensis en dosis de 40 mg/kg por vía endovenosa en el tren posterior aislado de 6 ratas normotensas (SDN) y 6 ratas hipertensas (SHR). El extracto provocó en ambas cepas de ratas una reducción significativa del retorno venoso. Se concluye que el extracto de Clusia provoca un efecto vasoconstrictor periférico, por lo que el efecto hipotensor y anti-hipertensivo encontrado anteriormente, podría ser atribuido a un efecto directo sobre el miocardio, mediante una disminución en la fuerza de la contracción cardíaca (efecto inotrópico negativo). Aqueous leaf extract of Clusia coclensis was applied at a dose of 40 mg/kg intravenously to isolated posterior extremities of six normotensive Sprague-Dawley rats and six Spontaneously Hipertensive rats anaesthetized with sodium nembutal. The perfusion was done in the abdominal artery using as carrier Krebs bicarbonate ringer at 37 °C and keeping constant perfusion pressures of 100 mmHg in normotensive rats and 150 mmHg in hipertensive ratas. The venous return was measured in the inferior vena cava. The extract induced a significant reduction of the venous return begining 2 min after application, in both rat types. This may reflect a peripheral vasoconstriction that, in whole organism,would have an hipertensive effect. Therefore, the mechanism of the alledgedly systemic hipotensive effect of the aqueous extract of Clusia coclensis leafs resides probably at a central level, probably acting by a reduction of the contractibility of the myocardium.
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