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Search Results: 1 - 10 of 196039 matches for " Ernesto; Díaz-Ferguson "
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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.
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
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.
Leer o no leer
Ernesto Díaz Couder Cabral
Revista Intercontinental de Psicología y Educación , 2009,
Abstract:
La anexión de los 6 municipios vecinos a BOGOTá en 1954 “UN HECHO CON ANTECEDENTES” The annexation of the 6 surrounding municipalities to Bogotá in 1954. “A prior fact”
Cortés Díaz Marco Ernesto
Bitácora Urbano-Territorial , 2011,
Abstract: La anexión de los seis municipios vecinos a Bogotá en 1954, es un proceso urbano, político y económico iniciado a mediados del siglo XIX, continuado a lo largo del siglo XX. Este buscaba confirmar a Bogotá como capital de Colombia, permitiéndole a la ciudad no estar dentro del regimen municipal ordinario de los demás municipios y ampliar su territorio, urbanizado en las décadas finales del siglo XX. En este artículo se verá cómo a cada cambio de ideas políticas corresponde necesariamente una modificación en el territorio y en la manera como se toman las decisiones. The annexation of the six surrounding municipalities to Bogotá in 1954, was an urban, political and economic process initiated by the middle of the XIX century, and continued along the XX century. The purpose of this annexation was to reaffirm Bogotá as the capital of Colombia, and keep it out of the ordinary municipal regime ruling the rest of the other municipalities, which allowed Bogotá to enlarge its territory. This will be developed by the urbanization process carried out over the final decades of the XX Century. In this article we will conclude that each change of political ideas basically implies a modification in the territory, and also in the way the decisions are made.
Hamiltonian BF theory and projected Borromean Rings
Ernesto Contreras,Adalberto Díaz,Lorenzo Leal
Physics , 2011, DOI: 10.1142/10.1142/S0217732312500691
Abstract: It is shown that the canonical formulation of the abelian BF theory in D = 3 allows to obtain topological invariants associated to curves and points in the plane. The method consists on finding the Hamiltonian on-shell of the theory coupled to external sources with support on curves and points in the spatial plane. We explicitly calculate a non-trivial invariant that could be seen as a "projection" of the Milnor's link invariant MU(1; 2; 3), and as such, it measures the entanglement of generalized (or projected) Borromeans Rings in the Euclidean plane.
Efectividad de un extracto de placenta humana con Calcio (Melagenina Plus) en el tratamiento del Vitiligo Effectiveness of a Human Placental Extract with Calcium (Melagenina Plus) for the treatment of Vitiligo
Carlos Manuel Miyares Cao,Ileana Hollands Barca,Ernesto Miyares Díaz,Ernesto Miyares Díaz
Revista Cubana de Investigaciones Biom??dicas , 2009,
Abstract: Introducción: Extractos alcohólicos de placenta humana han demostrado que poseen acción sobre la melanogénesis y sobre la proliferación de los melanocitos. Tales extractos producen un incremento en la densidad de los melanocitos así como de los gránulos de melanina cuando son aplicados tópicamente sobre las orejas y colas de ratones negros. Objetivo: Evaluar la acción de un extracto alcohólico de placenta humana con calcio (Melagenina Plus) en el tratamiento del Vitiligo, por ser esta una enfermedad en la que se pierden los melanocitos y por ende el pigmento melánico. Material y Método: Se realizó un estudio retrospectivo con 300 pacientes de vitiligo cubanos que fueron seleccionados por haber realizado de forma correcta la aplicación del extracto alcohólico de placenta humana con calcio sobre sus áreas despigmentadas. La selección se realizó con pacientes que se incorporaron al tratamiento con Melagenina Plus en los Servicios Clínicos del Centro de Histoterapia Placentaria entre los a os 1998 hasta el 2003. Resultados: Al final del estudio 231 pacientes mostraron repigmentación completa o notable, 28 repigmentación parcial, 24 ninguna repigmentación y 17 nuevas lesiones. Conclusiones: Nuestros resultados demuestran que el extracto alcohólico de placenta con adición de calcio puede ser un eficaz e inocuo tratamiento del Vitiligo. Introduction: Human placental alcohol extract have been successfully used on melanogenesis and melanocyte proliferation. Such extracts cause an increase in the number of melanocytes and melanin granules when applied topically on the ears and tails of black mice. Objectives: Assessment of the effectiveness of a human placental alcohol extract with calcium (Melagenina Plus) for the treatment of vitiligo, since this disease is characterized by melanocyte loss and consequently of melanine pigment. Material and methods: A retrospective study was carried out with 300 cuban vitiligo patients which were chosen because of their correct application on their depigmented areas of the human placental alcohol extract with calcium. Patients selection was made among those involved in the treatment with Melagenina Plus from the Clinical Service of the Placental Histotherapy Center since 1998 to 2003. Results: At the end of the study, 231 patients showed total or marked repigmentation, 28 moderate repigmentation, 24 no repigmentation and 17 new lesions. Conclusions: Results demonstrate that placental alcohol extracts with calcium added can be very effective and innocuous for the vitiligo treatment.
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