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Search Results: 1 - 10 of 51593 matches for " Carlos; Valera "
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Diversidad de ácaros (Acari: Prostigmata, Mesotigmata, Astigmata) asociados a la hojarasca de formaciones vegetales del Parque Universitario de la UCLA, Venezuela
Vásquez, Carlos;Sánchez, Carlos;Valera, Neicy;
Iheringia. Série Zoologia , 2007, DOI: 10.1590/S0073-47212007000400017
Abstract: soil mite diversity (prostigmata, mesostigmata, astigmata) inhabiting in litter-soil layer from a shrubland and a deciduous forest was estimated from december 2000 to november 2001 in the university park of ucla (universidad centroccidental lisandro alvarado), state of lara, venezuela. samplings were made by using pitfall traps along an 1,800 m-transect in both areas. all morfotypes were mounted in microscope slides using hoyer's medium. a total of 51 mite morfotypes were collected with higher abundance in prostigmata (2,528) as compared to mesostigmata (926) and astigmata (12). eupodidae (prostigmata) and macrochelidae (mesotigmata) showed higher abundance in both locations. higher morfotype richness (s= 43), diversity (h'= 2.67) and evenness (e= 0.69) were found in deciduous forest compared to values from shrubland (s= 36, h'= 2.12 and e= 0.52). both areas showed a similarity index (j') of 0.59. although more individuals were found in shrubland, the diversity-dominance curves indicated that this is a more disturbed habitat than deciduous forest. further detailed studies are required to determine acarofauna role in trophic web maintenance in soils from tropical areas.
Nota técnica
Giffoni,Jennifer; Valera,Neicy; Díaz,Francisco; Vásquez,Carlos;
Bioagro , 2007,
Abstract: abstract chrysoperla externa (hagen) is an important insect predator on several agricultural pests. effect of feeding on several preys on life span of c. externa was studied under laboratory conditions (27 ± 2 oc mean temperature and 60 ± 5 % r.h.). each of the following preys was daily offered ad libitum to predator: sitotroga cerealella (oliver), aphis craccivora (koch), aphis nerii boyer de fonscolombe, thrips tabaci lyndeman and tetranychus cinnabarinus (boisduval). duration of larval stage was significant lower (7.7 and 10.15 days) when fed on s. cerealella or a. craccivora, whilst when fed on a. nerii, t. tabaci and t.cinnabarinus it lasted 20.3, 19.1 and 16.4 days, respectively. predator reached pupal stage just when fed on s. cerealella eggs or a. craccivora nymphs and adults showing time mean of 7.95 and 7.55 days, respectively. conversely, only one individual reached this stage when feeding on a. nerii or t. tabaci, and no predator reached pupal stage when t. cinnabarinus was used as food source. it is concluded that s. cerealella and a. craccivora were the most adequate food sources for predator development, while a. nerii, t. tabaci and t. cinnabarinus resulted less appropriate
Nota técnica Biological cycle of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) feeding on several preys
Jennifer Giffoni,Neicy Valera,Francisco Díaz,Carlos Vásquez
Bioagro , 2007,
Abstract: RESUMEN Chrysoperla externa (Hagen) es un insecto importante como depredador de varias plagas agrícolas. Se evaluó el efecto de la alimentación con diferentes presas sobre la duración del ciclo biológico del mismo bajo condiciones de laboratorio (27 ± 2 oC de temperatura y 60 ± 5 % de HR). Diariamente, cada una de las siguientes presas fue ofrecida sin restricciones al depredador: Sitotroga cerealella (Oliver), Aphis craccivora (Koch), Aphis nerii Boyer de Fonscolombe, Thrips tabaci Lyndeman y Tetranychus cinnabarinus (Boisduval). Se obtuvieron diferencias significativas en la duración promedio de la fase larval (7,7 y 10,15 días) cuando esta se alimentó de S. cerealella o A. craccivora, mientras que al usar A. nerii, T. tabaci y T. cinnabarinus, la larva duró en promedio 20,3; 19,1 y 16,4 días, respectivamente. El estado de pupa del depredador sólo fue alcanzado cuando éste fue alimentado con huevos de S. cerealella o ninfas y adultos de A. craccivora con los cuales se obtuvo una duración promedio de la pupa de 7,95 y 7,55 días, respectivamente. Contrariamente, sólo un individuo del depredador logró alcanzar este estadío cuando fue alimentado con A. nerii y T. tabaci, mientras que aquellos depredadores alimentados con T. cinnabarinus no lograron desarrollarse hasta pupa. Se concluye que las presas más adecuadas para el desarrollo del depredador fueron S. cerealella y A. craccivora mientras que A. nerii, T. tabaci y T. cinnabarinus no resultaron apropiadas ABSTRACT Chrysoperla externa (Hagen) is an important insect predator on several agricultural pests. Effect of feeding on several preys on life span of C. externa was studied under laboratory conditions (27 ± 2 oC mean temperature and 60 ± 5 % R.H.). Each of the following preys was daily offered ad libitum to predator: Sitotroga cerealella (Oliver), Aphis craccivora (Koch), Aphis nerii Boyer de Fonscolombe, Thrips tabaci Lyndeman and Tetranychus cinnabarinus (Boisduval). Duration of larval stage was significant lower (7.7 and 10.15 days) when fed on S. cerealella or A. craccivora, whilst when fed on A. nerii, T. tabaci and T.cinnabarinus it lasted 20.3, 19.1 and 16.4 days, respectively. Predator reached pupal stage just when fed on S. cerealella eggs or A. craccivora nymphs and adults showing time mean of 7.95 and 7.55 days, respectively. Conversely, only one individual reached this stage when feeding on A. nerii or T. tabaci, and no predator reached pupal stage when T. cinnabarinus was used as food source. It is concluded that S. cerealella and A. craccivora were the most adequate food sources for pre
Nuevos registros y distribución de especies de trichogramma (hymenoptera: trichogrammatidae) en el Estado Lara, Venezuela New reports and distribution of Trichogramma species (Hymenoptera: Trichogrammatidae) in Lara State, Venezuela
José Morales,Carlos Vásquez,Neicy Valera,Norayda Arrieche
Bioagro , 2010,
Abstract: Se realizaron estudios de campo y de laboratorio para obtener nuevos registros y distribución de las especies del género Trichogramma en varios municipios del estado Lara, Venezuela. En el campo, las especies fueron obtenidas mediante trampas con huevos de Sitotroga cerealella (Olivier) y por colecta de huevos de lepidópteros en hojas de varios cultivos. En el laboratorio, los machos de Trichogramma fueron montados en láminas microscópicas para observar la genitalia y otros caracteres morfológicos usados para su identificación. Se encontró Trichogramma atopovirilia Oatman y Platner parasitando huevos de lepidópteros en los municipios Morán y Jiménez, mientras que Trichogramma pretiosum (Riley) lo fue en Morán y Andrés Eloy Blanco. Ambas especies ejercieron su parasitismo sobre varios hospederos localizados a diferentes pisos altitudinales. Los reportes de T. atopovirilia parasitando huevos de Spodoptera frugiperda en Quíbor (municipio Jiménez) y T. pretiosum en huevos de Agraulis vanillae (L.) en Sabana Grande (municipio Andrés Eloy Blanco), así como Trichogramma sp.1 en huevos de Utetheisa ornatrix y Trichogramma sp.2 en huevos de Erinnyis sp. en El Pampero (municipio Iribarren), constituyen nuevos hallazgos de este parasitoide para el estado Lara. Field and laboratory studies were conducted to obtain new distribution records of Trichogramma wasp species in Lara State, Venezuela. In the field, specimens were obtained from traps containing eggs of Sitotroga cerealella (Olivier) and from lepidopteran egg samples collected from various crop leaves. In the laboratory, specimens of Trichogramma were mounted on microscope slides to show male genitalia and other morphological characters used for identification. It was found that Trichogramma atopovirilia Oatman y Platner emerged from lepidopteran eggs in Morán and Jiménez Municipalities, while T. pretiosum did it in Morán and Andrés Eloy Blanco. Both species exerted their parasitism on several hosts located at different altitudes. The reports of T. atopovirilia parasitizing eggs of Spodoptera frugiperda in Quíbor (Jiménez Municipality), T. pretiosum in eggs of Agraulis vanillae (L.) in Sabana Grande (Andrés Eloy Blanco Municipality), and Trichogramma sp.1 in eggs of Ornatrix Utetheisa (L.) and Trichogramma sp.2 in eggs of Erinnyis sp. in El Pampero (Iribarren Municipality) are new records for this parasitoid in Lara State.
Olayo Díaz Giménez (1810-1885): un buen ejemplo de científico Intermedio
López Fernández, Carlos,Valera Candel, Manuel
Asclepio : Revista de Historia de la Medicina y de la Ciencia , 2001,
Abstract: In this paper we offer a general view of the life and work of Olayo Diaz Giménez (1810-1885), especially during his stage in the city of Murcia, where he lived from 1862 to his death. The paper is divided into four sections. After providing a biographical account of Olayo Díaz, his work as a teacher is approached, with emphasis on his role in the creation of the Physics Cabinet at the Provincial Institute (Secondary School). The following section highlights his activity in promoting the science of his time through his collaborations in the local newspapers and his involvement in the introduction of evolutionism in Murcia. Finally, we look at his period in charge of the Meteorological Office, with emphasis on both his observations as his book on the weather of Murcia. As a result of our study, Olayo Diaz appears as one of the key-scientists in the Murcia of the XIXth century, and as a typical representative of so-called intermediate scientists , or those that, without possessing an outstanding work of their own, collaborated decisively to create and maintain the necessary conditions to promote scientific activity in Spain. En este trabajo se ofrece una panorámica general sobre la vida y obra del catedrático Olayo Díaz Giménez (1810-1885), referida sobre todo a la etapa que vivió en la ciudad de Murcia, a la que llegó en 1862 y donde ya permaneció hasta su muerte. El trabajo ha sido estructurado en cuatro apartados, dentro de los cuales, junto a una rese a biográfica, se aborda la labor de Díaz como docente, como propagador de la ciencia de su época y como encargado de la Estación meteorológica. A su vez, dentro de la primera de estas facetas, destacó
BMP-2/6 Heterodimer Is More Effective than BMP-2 or BMP-6 Homodimers as Inductor of Differentiation of Human Embryonic Stem Cells
Elvira Valera,Michael J. Isaacs,Yasuhiko Kawakami,Juan Carlos Izpisúa Belmonte,Senyon Choe
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0011167
Abstract: Bone Morphogenetic Protein (BMP) signaling pathways are involved in differentiation of stem cells into diverse cell types, and thus BMPs can be used as main guidance molecules for in vitro differentiation of human stem cells.
In vitro evaluation of apical microleakage using different root-end filling materials
Valera, Márcia Carneiro;Camargo, Carlos Henrique Ribeiro;Carvalho, Alessandra Sverberi;Gama, Eduardo Ramalho Pereira;
Journal of Applied Oral Science , 2006, DOI: 10.1590/S1678-77572006000100010
Abstract: the objective of this study was to evaluate the apical leakage of retrograde cavities filled with portland cement (concrebrás s/a-mg-brazil), proroot mtatm (dentsply international, johnson city, tn, usa) and sealapex (kerr corporation, orange, california, usa) with addition of zinc oxide (odahcam herpo produtos dentários ltda, rio de janeiro, rj, brazil). forty-two extracted single-rooted human teeth were decoronated and used for this study. the root canals were instrumented at 1.0mm short of the apical foramen using the step-back technique to an apical iso size 60. the roots were obturated with gutta-percha points and sealer sealapex (kerr corporation-usa) and then 3mm of each root apex was sectioned at a 90° angle. ultrasonic retrograde preparation was performed with a diamond tip to 3mm depth and the roots were randomly divided into 3 groups according to the filling material: g1-portland, g2-proroot mta, g3- sealapex zinc oxide-added cement. the root surfaces were covered with nail varnish up to 2mm from the apical foramen, immersed in simulated tissue fluid for 30 days, and then immersed in 0.2% rhodamine b solution for 24 hours for evaluation of marginal leakage. the results showed mean leakage of 0.75, 0.35 and 0.35 for groups 1, 2 and 3, respectively; however, kruskal-wallis test revealed that there was no statistically significant difference among the results (p>0.05).
Nuevos registros y distribución de especies de trichogramma (hymenoptera: trichogrammatidae) en el Estado Lara, Venezuela
Morales,José; Vásquez,Carlos; Valera,Neicy; Arrieche,Norayda; Arcaya,Evelín; Querino,Ranyse B;
Bioagro , 2010,
Abstract: field and laboratory studies were conducted to obtain new distribution records of trichogramma wasp species in lara state, venezuela. in the field, specimens were obtained from traps containing eggs of sitotroga cerealella (olivier) and from lepidopteran egg samples collected from various crop leaves. in the laboratory, specimens of trichogramma were mounted on microscope slides to show male genitalia and other morphological characters used for identification. it was found that trichogramma atopovirilia oatman y platner emerged from lepidopteran eggs in morán and jiménez municipalities, while t. pretiosum did it in morán and andrés eloy blanco. both species exerted their parasitism on several hosts located at different altitudes. the reports of t. atopovirilia parasitizing eggs of spodoptera frugiperda in quíbor (jiménez municipality), t. pretiosum in eggs of agraulis vanillae (l.) in sabana grande (andrés eloy blanco municipality), and trichogramma sp.1 in eggs of ornatrix utetheisa (l.) and trichogramma sp.2 in eggs of erinnyis sp. in el pampero (iribarren municipality) are new records for this parasitoid in lara state.
Científicos Espa oles en el Reino Unido (1750-1830)
Valera, Manuel,López Sánchez, Juan Francisco,López Fernández, Carlos
Asclepio : Revista de Historia de la Medicina y de la Ciencia , 1998,
Abstract: The main object of this article is to explain in detail the continous movement of Spanish people, that by some reason, lived in the U. K. from mid XVIIIth century until the 30's in the XIXth century. Hereby is exposed the main features carried out by Spanish scientist in England, as well as their respective work areas. Afterwords, are numbered the Spanish people associated to the most emblematic British science institution of those days, the Royal Society of London. El objeto del presente trabajo es dar cuenta detallada del flujo casi continuo de espa oles que, por uno u otro motivo, realizaron alguna estancia en el Reino Unido desde mediados del siglo XVIII hasta los a os treinta del siglo XIX. Exponemos primeramente los rasgos más sobresalientes de la actividad desplegada por los científicos espa oles en Inglaterra, encuadrada en sus respectivas áreas de trabajo, y posteriormente damos noticia de los espa oles asociados a la institución científica británica más emblemática de la época, la Royal Society of London.
Cambios en los usos y coberturas del suelo en el municipio de Elx (1956-2005)
Valera Lozano, Antonio,A?ó Vidal, Carlos,Sánchez Díaz, Juan
Estudios Geográficos , 2011,
Abstract: L’objectif principal de cet article est d’approfondir les dynamiques des usages et des couvertures du sol de 1956 à 2005 dans la municipalité d’Elx (est d’Espagne). Afin d’observer ces modifications à une échelle détaillée (1:10.000), la photo-interprétation de photographies aériennes datées de 1956, 1985 et 2005 et l’analyse cartographique avec les Systèmes d’Information Géographique ont été pris en compte. Seize indicateurs ont aussi été appliqués pour évaluer le niveau de durabilité environnementale. Les résultats montrent quelques changements importants survenus au cours de la période d’étude: a) la croissance des aires urbaines dans les sols les plus fertiles et les zones les mieux connectées, b) l’intensification des pratiques agricoles, notamment des aridocultures qui se sont transformés en cultures d’irrigation, et c) la diminution des zones boisées et seminaturelles. [es] El objetivo principal de este artículo es analizar la dinámica espacial y temporal de los usos y coberturas del suelo entre 1956 y 2005 en Elx (Alicante). Mediante la fotointerpretación de fotografías aéreas de distintas fechas (1956, 1985 y 2005) y análisis cartográfico con Sistemas de Información Geográfica, se han establecido los cambios a escala detallada (1:10.000). También se han aplicado dieciséis indicadores para evaluar el nivel de sostenibilidad ambiental. Durante el periodo de estudio, se han producido importantes modificaciones: a) expansión de las superficies construidas, principalmente sobre los suelos más fértiles y las zonas mejor comunicadas, b) intensificación de las prácticas agrícolas debido a la conversión de cultivos de secano en regadío, y c) disminución de los bosques y las áreas seminaturales. [fr] Changements dans les usages et les couvertures du sol dans la municipalité d’Elx (1956-2005) L’objectif principal de cet article est d’approfondir les dynamiques des usages et des couvertures du sol de 1956 à 2005 dans la municipalité d’Elx (est d’Espagne). Afin d’observer ces modifications à une échelle détaillée (1:10.000), la photo-interprétation de photographies aériennes datées de 1956, 1985 et 2005 et l’analyse cartographique avec les Systèmes d’Information Géographique ont été pris en compte. Seize indicateurs ont aussi été appliqués pour évaluer le niveau de durabilité environnementale. Les résultats montrent quelques changements importants survenus au cours de la période d’étude: a) la croissance des aires urbaines dans les sols les plus fertiles et les zones les mieux connectées, b) l’intensification des pratiques agricoles, notamment des aridocult
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