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Search Results: 1 - 10 of 193022 matches for " Edgardo Díaz-Ferguson "
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Population Genetics of a Trochid Gastropod Broadens Picture of Caribbean Sea Connectivity
Edgardo Díaz-Ferguson,Robert Haney,John Wares,Brian Silliman
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012675
Abstract: Regional genetic connectivity models are critical for successful conservation and management of marine species. Even though rocky shore invertebrates have been used as model systems to understand genetic structure in some marine environments, our understanding of connectivity in Caribbean communities is based overwhelmingly on studies of tropical fishes and corals. In this study, we investigate population connectivity and diversity of Cittarium pica, an abundant rocky shore trochid gastropod that is commercially harvested across its natural range, from the Bahamas to Venezuela.
Observaciones sobre la larva del cangrejo marino tropical (Decapoda: Porcellanidae) Petrolisthes armatus en el Golfo de Nicoya, Costa Rica
Díaz-Ferguson,Edgardo; Arroyo,Daisy; Morales,Alvaro; Vargas,José A;
Revista de Biología Tropical , 2008,
Abstract: observations on the larvae of the tropical marine crab petrolisthes armatus in the gulf of nicoya, costa rica. during october and november 1998 (rainy season), and december, february and march 1999 (dry season), larvae distribution of petrolisthes armatus and associated decapods were sampled in three different sites at the punta morales peninsula, gulf of nicoya, costa rica. a total of 6014 decapod larvae were collected, and 73 belonged to the genus petrolisthes spp. no significant total larval density differences were found between seasons (p>0.05); but there was a greater density of p. armatus and other decapod larvae (p>0.05) during the dry season. in addition, no significant variations on temperature and oxygen concentration were observed. p. armatus larval abundance was higher during low tide, in contrast with other decapod larvae. significant differences among sites were found for other decapod larvae, but not for p. armatus. the only parameter that varied significantly between seasons was salinity and results demonstrate that this factor regulates temporal concentration of larvae. moreover, flow-tide oscillations were the most important spatial factor in larval dynamics. we propose this mechanism: p. armatus liberates larvae during high tide; these larvae leave the coastal area during low tide and return to the rocky intertidal ecosystem during high tide, when they are ready to settle as megalopa (pre-juvenile stage). parallel laboratory observations showed higher survival rates at lower salinities (15 ups against 35 ups) and that the duration of the period from zoea i to megalopa was, in average, 19 days. rev. biol. trop. 56 (3): 1209-1223. epub 2008 september 30.
Observaciones sobre la larva del cangrejo marino tropical (Decapoda: Porcellanidae) Petrolisthes armatus en el Golfo de Nicoya, Costa Rica
Edgardo Díaz-Ferguson,Daisy Arroyo,Alvaro Morales,José A Vargas
Revista de Biología Tropical , 2008,
Abstract: Durante octubre y noviembre de 1998 (estación lluviosa) y diciembre, febrero y marzo de 1999 (estación seca) se muestreó la distribución de la larva de Petrolisthes spp, así como la densidad del total de las larvas de decápodos en superficie y a 3 metros de profundidad. Los muestreos se realizaron en tres sitios de la zona de Punta Morales, Golfo de Nicoya, Costa Rica, por medio de arrastres con una red de plancton de 280 μm. Se recolectaron un total de 6014 larvas de decápodos de las cuales 73 (1.21%) pertenecían al género Petrolisthes spp. No se encontraron diferencias significativas entre estaciones (p > 0.05), sin embargo fue posible observar una mayor densidad tanto de P. armatus como de larvas de decápodos en estación seca. Temporalmente el único parámetro físico-químico que varió significativamente fue la salinidad. En cuanto a la variación espacial no se encontraron diferencias significativas por profundidad, ni para Petrolisthes spp. ni para larvas de decápodos asociados (p > 0.05), a pesar de que la variación de algunos parámetros como la temperatura y el oxígeno si lo fue. Entre mareas se encontraron diferencias significativas para las larvas de Petrolisthes spp., no así para larvas de decápodos. Para la especie estudiada se observó un mayor número de larvas en marea baja. Entre los sitios hubo diferencias significativas para las larvas de decápodos, pero no para Petrolisthes spp.; físico-químicamente estos sitios son muy parecidos y solo difieren en penetración de luz, lo que parece no afectar a la larva de Petrolisthes. spp. Los resultados demuestran que el principal factor que regula la concentración temporal de las larvas es la salinidad, mientras que espacialmente las oscilaciones en el flujo mareal son de mayor importancia. Debido a las diferencias observadas marealmente para la concentración de larvas se propone el siguiente mecanismo: P. armatus libera sus larvas en el máximo de marea, éstas salen hacia fuera de la costa con la marea baja y se reincorporan con la marea alta, cuando están cerca de la fase previa al asentamiento (la megalopa). Adicional a los resultados en el medio natural para esta especie también se estudió en el laboratorio la duración del periodo larval y la supervivencia de las larvas a salinidades extremas utilizándose los valores máximos y mínimos registrados en el medio natural (15 ups y 35 ups). Este ensayo demostró que las larvas presentan un mayor porcentaje de supervivencia en salinidades menores (15 ups) y que la duración del período de desarrollo es de 19 dias. Observations on the larvae of the tropical mar
Composition of the zooplankton community,with emphasis in copepods, in Punta Morales,Golfo de Nicoya,Costa Rica
Brugnoli-Olivera,Ernesto; Díaz-Ferguson,Edgardo; Delfino-Machin,Mariana; Morales- Ramírez,Alvaro; Dominici Arosemena,Arturo;
Revista de Biología Tropical , 2004,
Abstract: the composition of the mesozooplanktonic community was studied in the punta morales estuary, gulf of nicoya,pacific coast of costa rica,during 1997.oblique plankton hauls were performed during high and low tide using a 280 μm mesh screen net equipped with a flowmeter.the community was characterized by holoplanktonic and meroplanktonic organisms.for the holoplanktonic community,the main groups were copepods (80%)and chaetognaths (16%).the most abundant species were the copepods acartia lilljeborgii and paracalanus parvus.a.lilljeborgii is a typical estuarine species that maintains high populations in estuarine systems.meroplankton was represented mainly by crustacean larvae (66%),and icthyoplankton (18%).the dominance of crustacean larvae and icthyoplankton is an evidence of the ecological importance of the punta morales zone.rev.biol.trop.52(4):897-902.epub 2005 jun 24.
Composition of the zooplankton community,with emphasis in copepods, in Punta Morales,Golfo de Nicoya,Costa Rica
Ernesto Brugnoli-Olivera,Edgardo Díaz-Ferguson,Mariana Delfino-Machin,Alvaro Morales- Ramírez
Revista de Biología Tropical , 2004,
Abstract: The composition of the mesozooplanktonic community was studied in the Punta Morales estuary, Gulf of Nicoya,Pacific coast of Costa Rica,during 1997.Oblique plankton hauls were performed during high and low tide using a 280 μm mesh screen net equipped with a flowmeter.The community was characterized by holoplanktonic and meroplanktonic organisms.For the holoplanktonic community,the main groups were copepods (80%)and chaetognaths (16%).The most abundant species were the copepods Acartia lilljeborgii and Paracalanus parvus.A.lilljeborgii is a typical estuarine species that maintains high populations in estuarine systems.Meroplankton was represented mainly by crustacean larvae (66%),and icthyoplankton (18%).The dominance of crustacean larvae and icthyoplankton is an evidence of the ecological importance of the Punta Morales zone.Rev.Biol.Trop.52(4):897-902.Epub 2005 Jun 24. Se estudió la composición de la comunidad mezoplanctónica en Punta Morales,Golfo de Nicoya, Pacífico de Costa Rica,en 1997,arrastrando oblicuamente una red de plancton (280 μm,con flujómetro)durante marea alta y baja.La comunidad estuvo caracterizada por la presencia de organismos holo y meroplanctónicos.Los principales grupos holoplanctónicos fueron copépodos (80%)y quetognatos (16%).Las especies más abundantes fueron los copépodos Acartia lilljeborgii y Paracalanus parvus;A. lilljeborgii es una especie estuarina típica que mantiene altas poblaciones en sistemas estuarinos.El meroplancton estuvo representado principalmente por larvas de crustáceos (66%),e ictioplancton (18%).La dominancia de larvas de crustáceos e ictioplancton evidencian la importancia ecológica de la zona de Punta Morales.
Caracterización genética mediante microsatélites de Solea senegalensis (Soleidae, Pleuronectiformes) en poblaciones naturales de la costa atlántica del suroeste de la Península Ibérica
Díaz-Ferguson, E;Cross, I;Barrios, M;Pino, A;Castro, J;Bouza, C;Martínez, P;Rebordinos, L;
Ciencias marinas , 2012,
Abstract: the senegalese sole, solea senegalensis, is an important commercial flatfish species with major fisheries located off the atlantic coast of the sw iberian peninsula. past information about the genetic structure and connectivity among natural populations of this species has been restricted to mitochondrial dna analysis. the present analysis of eight natural atlantic populations fished from lisbon to the gulf of cádiz, using nine microsatellite loci, identifies high intrapopulation genetic variability. out of 72 tests performed, a total of 19 statistically significant deviations from hardy-weinberg (h-w) expectations (24%), and 7 after bonferroni corrections (9%), were observed in the populations examined. most deviations from h-w expectations were caused by heterozygote deficiencies (positive fis values) attributed to null alleles predominantly occurring in two loci (sol ga12 and sol mij) and one population (río san pedro). pairwise genetic differentiation among populations was only found in comparisons involving río san pedro samples (five out of seven comparisons) and barbate samples (two out of seven comparisons). the observed genetic structure complements existing information from mitochondrial data and should contribute to future management of fisheries of this species, since some fisheries are not environmentally sustainable.
Rese a de "Jesús María Sanromá: An American Twentieth-Century Pianist" de Alberto Hernández
Edgardo Díaz Díaz
Centro Journal , 2009,
Abstract:
Discordancia en autopercepción de peso en población adulta de Talca Discordance between nutritional status and self perception of weight among adults from Talca, Chile
Verónica Mujica E,Elba Leiva M,Edgardo Rojas M,Nora Díaz
Revista médica de Chile , 2009,
Abstract: Background: Obesity is related to underestimation of one 's own weight. Aim: To determine the agreement between nutritional status and self perception ofweight status in apparently healthy adults from Talca. Subjects and methods: Data were obtained from a survey applied at 1007 randomly selected subjects, aged 18-74 years old (66% women). The survey identified age, gender, educational level and socioeconomic status. Self-perception of weight was estimated with pictures representing the four nutritional status categories: underweight, normal, overweight and obese. Body Mass index (BMI, kg/m2) was calculated to determine nutritional status. Statistical analysis included kappa índex, Bowman s symmetry test and a logistic regression model to calculate the odds ratio in different variables related to underestimation of weight. Results: Seventy three percent of subjects were overweight or obese and 44% underestimated their nutritional status. Sixty percent ofsubjects with a BMI between 25 and 26 kg/m2, perceived themselves as normal. A higher underestimation was observed in obese subjects (odds ratio (OR) 17.2 95% confidence intervals (CI) 10.9-27.1), in overweight individuals (OR 3.5 95% CI 2.3-5.3), in men (OR 1.5 95% CI 1.1-2.1) and in people aged from 45 to 59 years (OR 1.7 95% CI 1.0-2.7). Conclusion: Almost half of studied population had an erroneous self-perception ofweight, mainly due to underestimation. Obese subjects, males and people older than 45years were those with the higher degree of underestimation.
On the Short-Term Optimisation of a Hydro Basin with Social Constraints  [PDF]
Gloria Hermida, Edgardo D. Castronuovo
Computational Water, Energy, and Environmental Engineering (CWEEE) , 2013, DOI: 10.4236/cweee.2013.21002
Abstract:

In this paper, an optimisation problem for calculating the best energy bids of a set of hydro power plants in a basin is proposed. The model is applied to a real Spanish basin for the short-term (24-hour) planning of the operation. The algorithm considers the ecological flows and social consumptions required for the actual operation. One of the hydro plants is fluent, without direct-control abilities. The results show that the fluent plant can be adequately controlled by using the storage capacities of the other plants. In the simulations, the costs related to the social consumptions are more significant than those due to the ecological requirements. An estimate of the cost of providing water for social uses is performed in the study.

Green Index to Estimate Crop Nitrogen Status in Potato Processing Varieties
Giletto,Claudia Marcela; Díaz,Cecilia; Rattín,Jorge Edgardo; Echeverría,Hernán Eduardo; Caldiz,Daniel Osmar;
Chilean journal of agricultural research , 2010, DOI: 10.4067/S0718-58392010000100015
Abstract: nitrogen is the most important nutrient in growing potatoes (solanum tuberosum l.) because either a deficit or excess in its supply can affect yield and quality, resulting in economic losses. to make a rational use of this nutrient, it is necessary to monitor n status during crop development. the green index (iv) could be a valuable method to assess n sufficiency. in experiments with variable n supply, the iv was assessed during crop growth and an n sufficiency index was derived (isn-iv). the relationship between tuber yield and the iv and isn-iv was established, as well as the association between the iv and isn-iv and n concentration in the following varieties: innovator, bannock russet and gem russet. during the vegetative growth stage, the iv and isn-iv were respectively above 40 spad units and 93%; while n concentration in the plant was above 4% in the three varieties, which suggests the n supply was sufficient. during the tuber-bulking stage, the necessary iv and isn-iv thresholds to reach maximum yields were 40.6 and 35 spad units and 93.7 and 91% at 89 and 103 days after planting, respectively. we concluded that the chlorophyll meter is an appropriate tool to determine the nutritional status in potato crops. the iv and isn-iv values showed that the crop achieved maximum yields when n levels are above the threshold values found in this research.
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