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Search Results: 1 - 10 of 32735 matches for " Daniel; Macaya "
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The impact of local extinction on genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central Valley of Costa Rica: consequences for the conservation of plant genetic resources
Daniel Barrantes,Gabriel Macaya,Luigi Guarino,Jean Pierre Baudoin
Revista de Biología Tropical , 2008,
Abstract: Plant populations may experience local extinction and at the same time new populations may appear in nearby suitable locations. Species may also colonize the same site on multiple occasions. Here, we examined the impact of local extinction and recolonization on the genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central valley of Costa Rica. We compared genetic diversity from the samples taken from the populations before and after extinction at 13 locations using microsatellite markers. Locations were classified according to the occurrence of extinction episodes during the previous five years into three groups: 1) populations that experienced extinction for more than one year, and were later recolonized (recolonized), 2) populations that did not experience local extinction (control), and 3) populations that did not experience local extinction during the study, but were cut to experimentally simulate extinction (experimental). Our data did not show a clear tendency in variation in allele frequencies, expected heterozygosity, and effective number of alleles within and between groups of populations. However, we found that the level of genetic differentiation between samples collected at different times at the same location was different in the three groups of populations. Recolonized locations showed the highest level of genetic differentiation (mean Fst= 0.2769), followed by control locations (mean Fst= 0.0576) and experimental locations (mean Fst= 0.0189). Similar findings were observed for Nei’s genetic distance between samples (di,j= 0.1786, 0.0400, and 0.0037, respectively). Our results indicate that genetic change in lima beans depends on the duration and frequency of local extinction episodes. These findings also showed that control populations are not in equilibrium. Implications of these results for the establishment of conservation strategies of genetic resources of lima beans are discussed. Rev. Biol. Trop. 56 (3): 1023-1041. Epub 2008 September 30. Las poblaciones de plantas pueden experimentar extinción local, y al mismo tiempo, pueden surgir a sus alrededores nuevas poblaciones. Algunas especies pueden colonizar el mismo sitio en múltiples ocasiones. Aquí examinamos el impacto de la extinción local y recolonización en la estructura genética de poblaciones silvestres del frijol lima (Phaseolus lunatus) en el valle Central de Costa Rica. Comparamos la diversidad genética de muestras tomadas en poblaciones, antes y después de la extinción, en 13 sitios, usando marcadores de microsatélite. Según los episodios de exti
Accessing Maternal Health Services in Eastern Burma
Macaya Douoguih
PLOS Medicine , 2008, DOI: 10.1371/journal.pmed.0050250
Abstract:
Mensaje del se or Rector de la Universidad de Costa Rica en la celebración del cincuenta aniversario de la Revista de Biología Tropical
Gabriel Macaya
Revista de Biología Tropical , 2002,
Abstract:
The impact of local extinction on genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central Valley of Costa Rica: consequences for the conservation of plant genetic resources
Barrantes,Daniel; Macaya,Gabriel; Guarino,Luigi; Baudoin,Jean Pierre; Rocha,Oscar J;
Revista de Biología Tropical , 2008,
Abstract: plant populations may experience local extinction and at the same time new populations may appear in nearby suitable locations. species may also colonize the same site on multiple occasions. here, we examined the impact of local extinction and recolonization on the genetic structure of wild populations of lima beans (phaseolus lunatus) in the central valley of costa rica. we compared genetic diversity from the samples taken from the populations before and after extinction at 13 locations using microsatellite markers. locations were classified according to the occurrence of extinction episodes during the previous five years into three groups: 1) populations that experienced extinction for more than one year, and were later recolonized (recolonized), 2) populations that did not experience local extinction (control), and 3) populations that did not experience local extinction during the study, but were cut to experimentally simulate extinction (experimental). our data did not show a clear tendency in variation in allele frequencies, expected heterozygosity, and effective number of alleles within and between groups of populations. however, we found that the level of genetic differentiation between samples collected at different times at the same location was different in the three groups of populations. recolonized locations showed the highest level of genetic differentiation (mean fst= 0.2769), followed by control locations (mean fst= 0.0576) and experimental locations (mean fst= 0.0189). similar findings were observed for nei?s genetic distance between samples (di,j= 0.1786, 0.0400, and 0.0037, respectively). our results indicate that genetic change in lima beans depends on the duration and frequency of local extinction episodes. these findings also showed that control populations are not in equilibrium. implications of these results for the establishment of conservation strategies of genetic resources of lima beans are discussed. rev. biol. trop. 56 (3): 1023-1041. e
Absorbable stent: focus on clinical applications and benefits
Gonzalo N, Macaya C
Vascular Health and Risk Management , 2012, DOI: http://dx.doi.org/10.2147/VHRM.S22551
Abstract: bsorbable stent: focus on clinical applications and benefits Review (3661) Total Article Views Authors: Gonzalo N, Macaya C Published Date February 2012 Volume 2012:8 Pages 125 - 132 DOI: http://dx.doi.org/10.2147/VHRM.S22551 Received: 14 December 2011 Accepted: 16 January 2012 Published: 29 February 2012 Nieves Gonzalo, Carlos Macaya Interventional Cardiology, Cardiovascular Institute. Hospital Clinico San Carlos, Instituto de Investigación Sanitaria del Hospital Clinico San Carlos, Madrid, Spain Abstract: Coronary stents have improved very significantly the immediate and long-term results of percutaneous coronary interventions. However, once the vessel has healed, the scaffolding function of the stent is no longer needed, and the presence of a permanent metallic prosthesis poses important disadvantages. This has led to the idea of creating new devices that are able to provide mechanical support for a determined period and then disappear from the vessel, allowing its natural healing and avoiding the risks associated with having a permanent metallic cage, such as stent thrombosis. Absorbable stents currently appear as one of the most promising fields in interventional cardiology. The present article will review the available clinical evidence regarding these devices at present and their future perspectives.
Estudios sobre la Escherichia Coli
MANUEL RODRIGUEZ,JUAN MACAYA
Revista chilena de pediatría , 1956,
Abstract:
Absorbable stent: focus on clinical applications and benefits
Gonzalo N,Macaya C
Vascular Health and Risk Management , 2012,
Abstract: Nieves Gonzalo, Carlos MacayaInterventional Cardiology, Cardiovascular Institute. Hospital Clinico San Carlos, Instituto de Investigación Sanitaria del Hospital Clinico San Carlos, Madrid, SpainAbstract: Coronary stents have improved very significantly the immediate and long-term results of percutaneous coronary interventions. However, once the vessel has healed, the scaffolding function of the stent is no longer needed, and the presence of a permanent metallic prosthesis poses important disadvantages. This has led to the idea of creating new devices that are able to provide mechanical support for a determined period and then disappear from the vessel, allowing its natural healing and avoiding the risks associated with having a permanent metallic cage, such as stent thrombosis. Absorbable stents currently appear as one of the most promising fields in interventional cardiology. The present article will review the available clinical evidence regarding these devices at present and their future perspectives.Keywords: absorbable stent, bioresorbable stent, absorb, percutaneous coronary intervention
All-Plastic Electrochemical Transistor for Glucose Sensing Using a Ferrocene Mediator
Na Young Shim,Daniel A. Bernards,Daniel J. Macaya,John A. DeFranco,Maria Nikolou,Róisín M. Owens,George G. Malliaras
Sensors , 2009, DOI: 10.3390/s91209896
Abstract: We demonstrate a glucose sensor based on an organic electrochemical transistor (OECT) in which the channel, source, drain, and gate electrodes are made from the conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS). The OECT employs a ferrocene mediator to shuttle electrons between the enzyme glucose oxidase and a PEDOT:PSS gate electrode. The device can be fabricated using a one-layer patterning process and offers glucose detection down to the micromolar range, consistent with levels present in human saliva.
NUEVOS REGISTROS PARA LA FLORA DE CHILE: MAGALLANA PORIFOLIA CAV. (TROPAEOLACEAE), TRISTAGMA AMEGHINOI (SPEG.) SPEG. Y TRISTAGMA PATAGONICUM (BAKER) TRAUB (ALLIACEAE)
Faúndez Y.,Luis; Macaya B.,Jorge H.;
Gayana. Botánica , 2000, DOI: 10.4067/S0717-66432000000100008
Abstract: magallana porifolia cav., tristagma ameghinoi (speg.) speg. and tristagma patagonicum (baker) traub, are reported for first time for the chilean flora, growing in the region of aysen (region xi). the species are described and comments about their habitats are made
Variación del tama?o de frutos y semillas en 38 poblaciones silvestres de Phaseolus lunatus (Fabaceae) del Valle Central de Costa Rica
Vargas,Elida M; Castro,Emilio; Macaya,Gabriel; J. Rocha,Oscar;
Revista de Biología Tropical , 2003,
Abstract: we studied the morfological diversity in fruits and seeds in 38 wild populations of phaseolus lunatus var. lunatus (lima beans) in the central valley of costa rica. in order to do so, measured the lenght and width of the fruits and the lenght, width and thickness of seeds. we also calculated the ratio between these traits and determined the weight of 100 seeds. in general, we found significant variation between populations for all variables. when we grouped the 38 populations into eight geographical regions within the study area, we found significant differences between regions. however, the levels of variation between populations within geographical regions was larger than that found between geographical regions. these findings suggested that there is no clear relationship between these variables and the geographical grouping established in this study. the implications of these findings for the establishment of strategies for in situ conservation of wild populations of lima beans are discussed
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