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Search Results: 1 - 10 of 4784 matches for " Ernesto Brugnoli-Olivera "
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Trophic planktonic dynamics in a tropical estuary, Gulf of Nicoya, Pacific coast of Costa Rica during El Ni?o 1997 event
Brugnoli-Olivera,Ernesto; Morales-Ramírez,Alvaro;
Revista de biología marina y oceanografía , 2008, DOI: 10.4067/S0718-19572008000100008
Abstract: the trophic dynamics of the plankton from the gulf of nicoya, a tropical estuary in the pacific coast of costa rica, was conducted during dry and rainy seasons of 1997. water temperature, oxygen and salinity were measured at two different light penetration depths. inorganic nutrients, total and nannophytoplanktonic chlorophyll a were determined at each depth and additional samples were taken for phytoplankton taxonomic work. oblique zooplankton hauls were done and abundance, composition and dry weight of zooplankton were determined. indirect grazing rate estimate was calculated using the pigment budget. the study period coincided with an el ni?o event detected in the punta morales zone and reflected by a change in the physico-chemical water characteristics. some nutrient concentrations were correlated to the salinity, and significant differences were observed between the transition and rainy seasons in the phytoplankton biomass of the two fractions. a total of 43 phytoplankton taxa were identified and flagellates, centric and pennate diatoms represented 90% of the total phytoplankton abundance. in the zooplanktonic samples, copepods were the most abundant group and acartia lilljeborgii, pseudodiaptomus sp. and paracalanus parvus were the dominant herbivores; dry weight mean values of herbivorous copepods were between 0.6 and 50 mg m-3. grazing rate showed a mean of 0.67 ± 0.83 d-1. this study showed a seasonal behavior with changes in nutrient concentrations, availability of phytoplankton and rising temperatures through el ni?o. predation and grazing pressure produced changes in the structure of plankton (phyto and zooplankton) populations in the internal zone of gulf of nicoya
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.
Ictioplancton en la zona portuaria de Limón, Costa Rica
Arturo Dominici-Arosemena,Ernesto Brugnoli-Olivera,Sylvia Solano-Ulate,Helena Molina-Ure?a
Revista de Biología Tropical , 2000,
Abstract: Four sampling stations were set 200-500m off Limon Port, Costa Rica, at an average depth of 20 m. From October 1996 to May 1997 horizontal subsuperficial trawls were done for 12 minutes at a speed of 1.853 Km/h, with a 1 000 μm net were surveyed with. A total of 28 samples were processed and 104 physical-chemistry parameter measurements were taken. Average salinity was 30.1 + 3.7 and dissolved oxygen 6.9 + 0.6 mg l-1 reflecting good aeration throughout the sampling period. This suggests good mixture and a highly dynamic hydrography. Temperature showed no drastic variations (28.0 + 1.7 °C), possibly because of the constant mixing with shallow water. The highest larval counts were for November and early January and include families from reefs and estuaries (Balistidae, Lutjanidae) and from coastal areas (Centropomidae, Gerreidae, Haemulidae, Carangidae, Engraulidae, Hemirramphidae, and representative Pleuronectiformes) existing in a common area.
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.
Ictioplancton en la zona portuaria de Limón, Costa Rica
Dominici-Arosemena,Arturo; Brugnoli-Olivera,Ernesto; Solano-Ulate,Sylvia; Molina-Ure?a,Helena; Ramírez Coghi,Ana Rosa;
Revista de Biología Tropical , 2000,
Abstract: four sampling stations were set 200-500m off limon port, costa rica, at an average depth of 20 m. from october 1996 to may 1997 horizontal subsuperficial trawls were done for 12 minutes at a speed of 1.853 km/h, with a 1 000 μm net were surveyed with. a total of 28 samples were processed and 104 physical-chemistry parameter measurements were taken. average salinity was 30.1 + 3.7 and dissolved oxygen 6.9 + 0.6 mg l-1 reflecting good aeration throughout the sampling period. this suggests good mixture and a highly dynamic hydrography. temperature showed no drastic variations (28.0 + 1.7 °c), possibly because of the constant mixing with shallow water. the highest larval counts were for november and early january and include families from reefs and estuaries (balistidae, lutjanidae) and from coastal areas (centropomidae, gerreidae, haemulidae, carangidae, engraulidae, hemirramphidae, and representative pleuronectiformes) existing in a common area.
InBUy database of Invasive and Alien Species (IAS) in Uruguay: a useful tool to confront this threat to biodiversity
Masciadri, Silvana;Brugnoli, Ernesto;Muniz, Pablo;
Biota Neotropica , 2010, DOI: 10.1590/S1676-06032010000400026
Abstract: in uruguay, as well as in other regions of the world, ias cause negative impacts on natural and managed ecosystems. the use of databases is a helpful tool to elaborate different strategies for prevention and control, and to develop policies and scientific analyses related to ias. the database of ias in uruguay (inbuy) was developed during two time periods (2006-2007 and 2009-2010). it currently contains information on 33 specialists of different taxonomic groups, 14 research projects, 185 references, 351 species and 4,715 records, with vascular plants having both the highest number of species and records. among vascular plants, herbaceous life forms are the most strongly represented, followed by trees and shrubs. within animals, the fishes and mollusks are the most important groups. analysis of the native distribution areas of ias showed that most are indigenous from europe, followed by asia and oceania. data showed that introductions of ias into uruguay are mainly intentional (67%), so efforts should be focused on policies and rules in order to control the entrance of exotic organisms and prevent new invasions. the geography of the compiled dataset shows the main impact is along the coastline, where the highest exotic species richness and records occurs, and also the most biological invasions. the inbuy database is up-to-date and has successfully contributed to the creation of an official ias list for uruguay and both a national and a coastal geographic information system. it has also been used for developing consciousness about this important threat to biodiversity, at both national and regional scales.
Golden mussel Limnoperna fortunei (Bivalvia: Mytilidae) distribution in the main hydrographical basins of Uruguay: update and predictions
Brugnoli Ernesto,Clemente Juan,Boccardi Lucía,Borthagaray Ana
Anais da Academia Brasileira de Ciências , 2005,
Abstract: Limnoperna fortunei, an Asiatic rivers bivalve has become a worldwide problematic invasive species causing several water quality and macrofouling problems. In the Neotropical region it was first recorded in 1991 in the Río de la Plata coast, Buenos Aires province. Since this, it showed a quick upstream invasion into the principals aquatic systems of the Plata Basin. Nevertheless, there is not a study about its invasion and distribution process in aquatic systems of Uruguay. We describe the new records of Limnoperna fortunei in Uruguayan coast of Río de la Plata, Santa Lucía, Negro and Uruguay Rivers. With these results we aim to estimate its distributional limits for Uruguay main hydrographical basins. We also deal with the role of salinity as the main abiotic factor in limiting the east distribution of this mussel in Uruguayan coast of Río de la Plata and as a potential determinant of the "new" colonization on the Atlantic and the Merín Lagoon Basins. Its presence in the ecosystems not only can cause changes at the ecosystem level but also endanger the associated community, favoring the displacement and the disappearance of endemic species.
Computing Greeks for Lévy Models: The Fourier Transform Approach
Federico De Olivera,Ernesto Mordecki
Quantitative Finance , 2014,
Abstract: The computation of Greeks for exponential L\'evy models are usually approached by Malliavin Calculus and other methods, as the Likelihood Ratio and the finite difference method. In this paper we obtain exact formulas for Greeks of European options based on the Lewis formula for the option value. Therefore, it is possible to obtain accurate approximations using Fast Fourier Transform. We will present an exhaustive development of Greeks for Call options. The error is shown for all Greeks in the Black-Scholes model, where Greeks can be exactly computed. Other models used in the literature are compared, such as the Merton and Variance Gamma models. The presented formulas can reach desired accuracy because our approach generates error only by approximation of the integral.
Forest as Capercaillie's habitat: applied research efforts and new management experiences
Brugnoli A,Brugnoli R
Forest@ , 2006,
Abstract:
Golden mussel Limnoperna fortunei (Bivalvia: Mytilidae) distribution in the main hydrographical basins of Uruguay: update and predictions
Brugnoli, Ernesto;Clemente, Juan;Boccardi, Lucía;Borthagaray, Ana;Scarabino, Fabrizio;
Anais da Academia Brasileira de Ciências , 2005, DOI: 10.1590/S0001-37652005000200004
Abstract: limnoperna fortunei, an asiatic rivers bivalve has become a worldwide problematic invasive species causing several water quality and macrofouling problems. in the neotropical region it was first recorded in 1991 in the río de la plata coast, buenos aires province. since this, it showed a quick upstream invasion into the principals aquatic systems of the plata basin. nevertheless, there is not a study about its invasion and distribution process in aquatic systems of uruguay. we describe the new records of limnoperna fortunei in uruguayan coast of río de la plata, santa lucía, negro and uruguay rivers. with these results we aim to estimate its distributional limits for uruguay main hydrographical basins. we also deal with the role of salinity as the main abiotic factor in limiting the east distribution of this mussel in uruguayan coast of río de la plata and as a potential determinant of the "new" colonization on the atlantic and the merín lagoon basins. its presence in the ecosystems not only can cause changes at the ecosystem level but also endanger the associated community, favoring the displacement and the disappearance of endemic species.
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