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1

Venezuela.  

PubMed

The background notes by the U.S. State Department on Venezuela emphasize the unique economic conditions in this oil-rich nation, and include information on its people, geography, history, government politics, defense and foreign relations. Venezuela, located on the north coast of South America, has 17,791,000 people, growing at a rate of 2.7%. Infant mortality is 2.7/1000, and life expectancy is 70 years. Geography ranges from the scarcely populated highlands between the Orinoco river and Guyana, the Orinoco plains, to the populated Andes mountains and coast. 80% of the population is urban. Literacy is a priority at 88.4%; Technical and university education is increasing; emigration from other countries is common because of relatively good working conditions. Venezuela has a long history of self government, having become independent in 1921. Now the democratic constitutional government is effective in improving both internal and regional development and human rights. The economy is based on oil production and refining, as well as steel and aluminum, all nationalized industries. Self-sufficiency in agriculture is a national goal. Because of the rapid population growth rate, however, per capita income and GNP are stagnating. PMID:12177927

1987-04-01

2

Importancia de las plantas medicinales en el autocuidado de la salud en tres caseríos de Santa Ana Trujillo, Venezuela. The importance of medicinal plants in health care in three small villages of the Santa Ana county at Trujillo state, Venezuela  

Microsoft Academic Search

In order to gather some information about the importance of medicinal plants in the primary health care, the use of plants in three small villages of the Santa Ana county, Pampán municipality at Trujillo State, Venezuela, was quantitatively analyzed. To do this, a local epidemiology diagnosis was carried out and the etnopharmacological information obtained was recorded using the TRAMIL survey.

TEOLINDA CARRILLO-ROSARIO Y GLENDA

3

Venezuela Bolivariana.  

E-print Network

??Im Kontext des „Linksrucks“ auf dem lateinamerikanischen Kontinent, nimmt die Bolivarische Republik Venezuela eine besondere Stellung ein, denn ihre mehr als achtzigjährige Geschichte als erdölexportierende… (more)

Schmidt, Lukas

2013-01-01

4

Penas sin importancia y Tío Vania: Diálogo paródico entre Chejov y Gambaro  

E-print Network

FALL 1997 5 Penas sin importancia y Tío Vania: Diálogo paródico entre Chejov y Gámbaro Hortensia R. Morell Tanto el lector inocente que se dispone a la lectura del libreto de Penas sin importancia (1991), una de las últimas piezas teatrales de... que vengan" (Ure 19). Penas sin importancia ahonda en esa vena doblemente histriónica y facilita un atisbo en lo que Eduardo Rovner ha reconocido como el cuestionamiento en el teatro argentino de la década de los ochenta de los valores instalados...

Morell, Hortensia R.

1997-10-01

5

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Lecturas en Ciencias, Universidad Central de Venezuela, Ap. 47002, Caracas 1041-A, Venezuela (mmonsalv, Universidad Central de Venezuela, Ap. 47002, Caracas 1041-A, Venezuela (mraydan

Raydan, Marcos

6

Experimental Theatre in Venezuela  

E-print Network

4 LATIN AMERICAN THEATRE REVIEW Experimental Theatre in Venezuela The I Jornadas de Búsqueda y Experimentación Teatral took place March 21-May 19, 1985 in Caracas. Organized by the Centro Latinoamericano de Creación e Investigación Teatral... of the festival was to give an opportunity for experimental theatre groups to present their work and thus to show the current tendencies of unconventional theatre in Venezuela. The participating groups (among them Shock Teatral, Contradanza, Taller...

Editors

1985-10-01

7

Cephalopod Resources of Venezuela Introduction  

E-print Network

Cephalopod Resources of Venezuela Introduction The cephalopods in the Western Central Atlantic producing nations in the Western Central Atlantic are Mexico and Ven ezuela. While Venezuela has the lead in production of octopus (mainly Octopus maya). In Venezuela, both squid and octopus are produced as a by

8

THE PEARL FISHERY OF VENEZUELA  

E-print Network

THE PEARL FISHERY OF VENEZUELA Marine Biological Lafi'ir-toiy X.I B K. A. R TT JUN 2 41950 WOODS Albert M. Day, Director Special Scientific Report - Fisheries Ho. 26 THE PEARL FISHERY OF VENEZUELA Paul to Venezuela, made travel arrangements, arranged for the cooperation of Venecuelan agencies, and otheri

9

Venezuela`s gas industry poised for long term growth  

SciTech Connect

Venezuela`s enormous gas resource, combined with a new willingness to invite outside investment, could result in rapid growth in that industry into the next century. The development of liquefied natural gas exports will depend on the future course of gas prices in the US and Europe, but reserves are adequate to supply additional projects beyond the proposed Cristobal Colon project. Venezuela`s gas reserves are likely to increase if exploration for nonassociated gas is undertaken on a larger scale. The paper discusses gas reserves in Venezuela, internal gas markets, the potential for exports, competition from Trinidad, LNG export markets, and the encouragement of foreign investment in the gas industry of Venezuela.

Croft, G.D. [Pantera Petroleum Inc., San Leandro, CA (United States)

1995-06-19

10

Un teatro campesino en Venezuela  

E-print Network

102 LATIN AMERICAN THEATRE REVIEW Un teatro campesino en Venezuela GUILLERMO KORN Producto espontáneo de la participación colectiva nació el grupo de teatro del Asentamiento Campesino Sabaneta, en el Estado Aragua de Venezuela. Las obras de su..., despertó interés. En la Universidad Central de Venezuela quieren saber más de ustedes. Para eso he venido. . . ? ¿Podrían eventualmente hacer una representación en la Escuela de Comuni cación Social? Almeida: {Claro que sí! Si nos dan un medio para...

Korn, Guillermo

1976-10-01

11

Hctor L. Palacios Verdes Caracas, Venezuela  

E-print Network

Héctor L. Palacios Verdes Caracas, Venezuela Phone: ask Email: hectorpal@gmail.com Web page: http://www.ldc.usb.ve/~hlp Citizen: Venezuela Residence: Venezuela Education Ph. D. Informatics and Digital Communication December. Caracas, Venezuela. Thesis: Planning as Branch and Bound: a Constraint Programming implementation. Advisor

Palacios, Héctor

12

Enzootic transmission of yellow fever virus, Venezuela.  

PubMed

Phylogenetic analysis of yellow fever virus (YFV) strains isolated from Venezuela strongly supports YFV maintenance in situ in Venezuela, with evidence of regionally independent evolution within the country. However, there is considerable YFV movement from Brazil to Venezuela and between Trinidad and Venezuela. PMID:25531105

Auguste, Albert J; Lemey, Philippe; Bergren, Nicholas A; Giambalvo, Dileyvic; Moncada, Maria; Morón, Dulce; Hernandez, Rosa; Navarro, Juan-Carlos; Weaver, Scott C

2015-01-01

13

Enzootic Transmission of Yellow Fever Virus, Venezuela  

PubMed Central

Phylogenetic analysis of yellow fever virus (YFV) strains isolated from Venezuela strongly supports YFV maintenance in situ in Venezuela, with evidence of regionally independent evolution within the country. However, there is considerable YFV movement from Brazil to Venezuela and between Trinidad and Venezuela. PMID:25531105

Auguste, Albert J.; Lemey, Philippe; Bergren, Nicholas A.; Giambalvo, Dileyvic; Moncada, Maria; Morón, Dulce; Hernandez, Rosa; Navarro, Juan-Carlos

2015-01-01

14

Venezuela at a Crossroads: Will the re-election of Chvez be a victory for Venezuela?  

E-print Network

Venezuela at a Crossroads: Will the re-election of Chávez be a victory for Venezuela? November 2012 as having significantly changed the po- litical landscape and prospects for Venezuela, giving hope to the 44

Habib, Ayman

15

LA IMPORTANCIA DE LA CULTURA ORGANIZACIONAL EN LA GESTIÓN DE EMPRESAS TURÍSTICAS: EL CASO DE BLUE TREE HOTELS  

Microsoft Academic Search

Este trabajo analiza el papel y la importancia de la cultura organizacional y su forma de gestión en un contexto de globalización y rápidos cambios, con mercados y clientes cada vez más exigentes. La cultura organizacional es tratada como un factor relevante para la garantía de padrones de calidad, para el servicio y superación de las expectativas de los clientes

JOSÉ MANOEL; GONÇALVES GANDARA; Programa de Turismo; MARCELO GONÇALVES DE HARO; CAROLINA NARLOCH SASS DE HARO

16

UNIVERSIDAD SIMN BOLVAR Caracas-Venezuela  

E-print Network

UNIVERSIDAD SIM�N BOLÍVAR Caracas-Venezuela INFORME TRIMESTRAL ACERCA DE LA MARCHA DE LA UNIVERSIDAD julio ­ septiembre 2004 Junio, 2005 #12;#12;UNIVERSIDAD SIM�N BOLÍVAR Caracas-Venezuela INFORME

Vásquez, Carlos

17

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Lecturas en Ciencias-02 Centro CCCT Caracas, Abril, 2007. #12;Universidad Central de Venezuela Facultad de Ciencias Escuela de

Raydan, Marcos

18

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Lecturas en Ciencias Construcción de Algoritmos Ernesto Coto ecoto@strix.ciens.ucv.ve Universidad Central de Venezuela. Facultad de Ciencias. Escuela de Computación. Laboratorio de Computación Gráfica (LCG) Venezuela. Caracas Apdo. 47002

Coto, Ernesto

19

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Lecturas en Ciencias@lmpa.univ-littoral.fr) Departamento de Computaci´on, Facultad de Ciencias, Universidad Central de Venezuela, Ap. 47002, Caracas 1041-A, Venezuela (mraydan@kuaimare.ciens.ucv.ve). Sponsored by the Center of Scientific Com- puting at UCV. 1 #12

Raydan, Marcos

20

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Lecturas en Ciencias@opalo.ciens.ucv.ve Universidad Central de Venezuela. Facultad de Ciencias. Escuela de Computación. Laboratorio de Computación Gráfica (LCG) Venezuela. Caracas Apdo. 47002, 1041-A. ND 2003-02 Resumen Los grafos son solo abstracciones

Coto, Ernesto

21

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Una herramienta para. Universidad Central de Venezuela. {ecoto, hnavarro, omaira}@opalo.ciens.ucv.ve **Laboratorio TOOLS. Escuela de Computación. Facultad de Ciencias. Universidad Central de Venezuela. amatteo@isys.ciens.ucv.ve Caracas, Enero

Coto, Ernesto

22

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Lecturas en Ciencias ecoto@strix.ciens.ucv.ve ecoto@opalo.ciens.ucv.ve Universidad Central de Venezuela. Facultad de Ciencias. Escuela de Computación. Laboratorio de Computación Gráfica (LCG) Venezuela. Caracas Apdo. 47002, 1041-A ND

Coto, Ernesto

23

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Lecturas en Ciencias) for some E Cn�n with E Venezuela Venezuela, Centro de C´alculo Cient´ifico y Tecnol´ogico, (zenaida.castillo@ciens.ucv.ve). 1 #12;2 R

Astudillo, Reinaldo

24

Universidad Central de Venezuela Facultad de Ciencias  

E-print Network

Universidad Central de Venezuela Facultad de Ciencias Escuela de Computación Lecturas en Ciencias ecoto@strix.ciens.ucv.ve ecoto@opalo.ciens.ucv.ve Universidad Central de Venezuela. Facultad de Ciencias. Escuela de Computación. Laboratorio de Computación Gráfica (LCG) Venezuela. Caracas Apdo. 47002, 1041-A

Coto, Ernesto

25

Some Crustacea Copepoda from Venezuela  

Microsoft Academic Search

The study of 38 samples of aquatic fauna from Venezuela increased the number of known species here from 28 to 66. Fifteen new species for science are described. A list of Copepoda known from the other regions of South America is presented. From this list, it can be said that only 50% of the inland water Copepoda living actually in

B. H. Dussart

1984-01-01

26

Media and Consumerism in Venezuela.  

ERIC Educational Resources Information Center

Outlines opposing theories of the role of the commercial mass media in national economic development; reports on a survey of the attitudes of 636 adult residents of Barquisimeto, Venezuela, with respect to consumption, advertising, and national development, and shows how the results relate to the theory proposed by Daniel Lerner. (GT)

Martin, Richard; And Others

1979-01-01

27

Purposeful Play in Rural Venezuela  

ERIC Educational Resources Information Center

Describes how children in rural Venezuela are trained in agricultural skills by the extended family. The highly organized training encourages play and exploration as important elements in familiarzing children with implements and methods of food production. It is suggested that rural school planners draw ideas from the rural family's educative…

Chesterfield, Ray

1977-01-01

28

Como Lo Hago Yo: Myelomeningocele  

PubMed Central

Fortificación con ádico fólico es efectiva, pero aún falta conciencia en los jóvenes. La legalidad del aborto aumenta la importancia de la consulta prenatal. Realizo la cirugía bajo microcoscopio por razones didácticas. Irrigación continua para reducir la temperatura del tejido. Trato a la plaqueta como tejido viable. No suturo la plaqueta. No cierro músculo. ATB por una semana después de cirugía. Hidrocefalia: Válvula en todos los casos de ventriculomegalia. Médula anclada: Desanclar una sola vez. Chiari II: Revisar la válvula. Incluir en el seguimiento rendimiento escolar, puede indicar obstrucción de la válvula o médula anclada. PMID:24791217

Lazareff, Jorge

2014-01-01

29

Hydrocarbon potential of Central Monagas, Eastern Venezuela Basin, Venezuela  

SciTech Connect

The Central Monagas area is part of the foreland sub-basin located on the southern flank of the Eastern Venezuela Basin. The sedimentary column of the Central Monagas is at least 7500 in thick and consists of Mesozoic (Cretaceous) and Cenozoic rocks. Interpretations of 60 regional seismic sections have been integrated with data from 12 existing wells, which cover an area of 1200 km{sup 2}. From these interpretations, basin-wide structure and interval isopach maps were constructed in order to aid the depiction of the basin architecture and tectonic history. The sub-basin developed on the southern flank of the Eastern Venezuela Basin is tightly linked to its evolution from a Mesozoic extensional regime into a Cenozoic compressional and strike-slip stage. The basin formed in the Middle Mesozoic by crustal extension of a rifting process. Regional northward tilting of the slab continued during the Late Cretaceous. Finally, the transpression of the Caribbean Plate during the Oligocene-Neogene induced the overprint of compressional deformation associated with the deposition of a foredeep wedge. Geochemical source rock analysis gave an average of 1.2 TOC, and R{sub o} of 0.66 indicating a mature, marine source. The modeling of the hydrocarbon generative history of the basin indicates that the oil migration started in the Middle Miocene, after the trap was formed. Analysis and mapping of reservoir rocks and seal rocks defined the effective area limits of these critical factors. The main play in the area is the extension of the Lower Oficina Formation which is the proven petroleum target in the Eastern Venezuela Basin.

Barrios, F.; Daza, J.; Iusco, G. [Departamento de Geologia, Lagoven, S.A., Caracas (Venezuela)

1996-08-01

30

78 FR 55096 - Ferrosilicon from Russia and Venezuela  

Federal Register 2010, 2011, 2012, 2013, 2014

...Preliminary)] Ferrosilicon from Russia and Venezuela Determination On the basis of the record...by reason of imports from Russia and Venezuela of ferrosilicon, provided for in subheadings...imports of ferrosilicon from Russia and Venezuela. Accordingly, effective July 19,...

2013-09-09

31

Oil, Regionalism and the Changing Geopolitical Imaginations of Venezuela.  

E-print Network

??Through Venezuela?s past experiences with foreign influences including its relationship with foreign oil companies and international organizations like the IMF, the current Venezuelan government has… (more)

Salas, Christina Andrea

2008-01-01

32

Republic of Venezuela. Country profile.  

PubMed

Venezuela's current economic and demographic situation is described. Venezuela is a major oil country, and the oil industry accounts for 90% of the country's foreign exchange, 70% of the government's revenues, and 15% of the gross domestic product. The economy experienced a sudden and high rate of economic growth in the mid-1970s as a result of high oil prices; however, in recent years, declining oil prices have had a negative effect on the economy. The country is now faced with a serious trade deficit, and the government recently imposed restrictions on imports. Imports in recently years had increased markedly. The emphasis on the oil industry weakened the agricultural sector and, as a result, food imports increased. In addition, the rapid economic growth experienced during the 1970s greatly increased the demand for imported consumer goods. Venezuela has the 4th highest foreign debt in the world (US$35 billion). Despite these problems Venezuela has a relatively high per capita income (US$4,140) and living standard, compared to other countries in the region. Venezuela's total population is 14.6 million, and the population is unevenly distributed. 86% of the population lives in cities of 2500 or more. 37.4% of the population and 70% of the industry is concentrated in the Federal District which contains Caracas, and in the surrounding states of Aragua, Miranda, and Carabobo. This area constitutes only 2.36% of the country's territory. Most of the oil fields are located in the state of Zulia which also contains the country's 2nd largest city (Maracaibo). The country's coastal area contains most of the agricultural lands, and the prairies just south of the coastal mountain ranges are devoted primarily to cattle raising. The remaining 58.2% of the country's territory is essentially jungle and contains only 6.9% of the country's population. The annual population growth rate is 3.11%. Although the rate declined in recent years it is higher than in most of the other countries in the region. In 1981, 1 million of the countrys, residents were foreign born. The oil industry attracted many immigrants, and illegal immigration is a serious problem. 41% of the population is under 15 years of age, the birth rate is 33-37, the death rate is 5, the infant mortality rate is 39, and life expectancy is 69 years. Average household size is 5.28. Family life is highly unstable. 32% of the couples are in informal unions, and these couples account for 52% of all births. 20% of the households are headed by low income women. The total fertility rate was 6.7 in 1961 and is currently 4.3. There are 3.2 million housing units, and 800,000 of these are classified as inadequate. 65% of the population is mestizo, 20% is European, and the remaining 15% are from various other countries or members of indigenous groups. The population is predominantly Catholic. The literacy rate is 83%; however, 71% of the males and 84% of the females in rural areas are illiterate. 31.5% of the population is in the labor force, and 27.5% of the labor force is female. 20% of the labor force is in the service sector and many of these work in the overgrown government bureaucracy. Only 15% of the labor force is engaged in the primary sector. 37% of the residents of Caracas and 80% of the country's rural residents live below the poverty level. PMID:12313690

Hakkert, R

1985-06-01

33

FUNDAMENTOS TEÓRICOS DE LA COORDINACIÓN COMO PREMISA ESENCIAL PARA DESARROLLAR EL TRABAJO SOCIOCULTURAL COMUNITARIO  

Microsoft Academic Search

La cultura como conjunto de relaciones humanas que ha transcendido en el tiempo y que le permite al hombre conservar, reproducir, crear nuevos conocimientos y valores para la transformación de su medio social y cultural, cada día cobra mayor importancia como sostén fundamental para la satisfacción de las necesidades espirituales y como elemento de influencia directa en la producción de

Ricardo Basilio Enoa Leyva

2010-01-01

34

An Energy Overview of Venezuela  

SciTech Connect

The DOE Office of Fossil Energy is maintaining a web site that is meant to provide useful business- and energy-related information about countries and regions of the world for exporters, project developers, and researchers. The site consists of more than 130 country pages (organized into seven different world regions), with each country page having its own set of links to information sources about that country. There are also more than 30 Country Energy Overviews at the web site -- each of these is a comprehensive review of a specific country's entire energy situation, including sections on Energy Policy, Oil, Natural Gas, Coal, Hydroelectric/Renewables, Nuclear Power, Energy Transmission Infrastructure, Electricity, Electric Industry Overview, Environmental Activities, Privatization, Trade, and Economic Situation. The specific country highlighted in this Country Energy Overview is Venezuela. The site is designed to be dynamic. Updates to the overviews will be made as need and resources permit.

anon.

2003-10-20

35

Massive Variability Surveys from Venezuela  

E-print Network

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

Cesar Briceno

2003-04-03

36

An Example of Educational Transformation: Venezuela.  

ERIC Educational Resources Information Center

Presents a case study of educational development in Venezuela, with emphasis on political and cultural influences, social needs, needs of developing nations, experimentation on all levels, fellowship programs, and projections for the future. (DB)

Cirigliano, Gustavo F. J.

1979-01-01

37

Reformulated gasoline deal with Venezuela draws heat  

SciTech Connect

A fight is brewing in Congress over a deal to let Venezuela off the hook in complying with the Clean Air Act reformulated gasoline rule. When Venezuela threatened to call for a GATT panel to challenge the rule as a trade barrier, the Clinton Administration negotiated to alter the rule, a deal that members of Congress are characterizing as {open_quotes}secret{close_quotes} and {open_quotes}back door.{close_quotes}

Begley, R.

1994-04-06

38

78 FR 58556 - Silicomanganese From India, Kazakhstan, and Venezuela  

Federal Register 2010, 2011, 2012, 2013, 2014

...Silicomanganese From India, Kazakhstan, and Venezuela Determination On the basis of the record...silicomanganese from India, Kazakhstan, and Venezuela would be likely to lead to continuation...Commissioner Pearson dissenting with respect to...

2013-09-24

39

State and Power after Neoliberalism in Bolivarian Venezuela.  

E-print Network

??ABSTRACTState and Power after Neoliberalism in Bolivarian VenezuelaDonald V. KingsburyState and Power after Neoliberalism in Bolivarian Venezuela examines the limits and possibilities of collective subject… (more)

Kingsbury, Donald V.

2012-01-01

40

Venezuela : dix ans de gouvernement Chvez Julien Rebotier1  

E-print Network

1 Venezuela : dix ans de gouvernement Chávez Julien Rebotier1 , Sandrine Revet2 Au Venezuela, le mesures phares pour le proceso, du nom donné au « processus révolutionnaire » en cours au Venezuela. L du Parti socialiste unifié du Venezuela (PSUV). Les élections régionales du 23 novembre 2008 ont, en

Paris-Sud XI, Université de

41

Venezuela slates second oil field revival round  

SciTech Connect

This paper reports that Venezuela will accept bids under a second round next year from private foreign and domestic companies for production contracts to operate marginal active as well as inactive oil fields. The first such round came earlier this year, involving about 55 other marginal, inactive fields. It resulted in two contractors signed with domestic and foreign companies. It represented the first time since nationalization of the petroleum industry in Venezuela in 1976 that private companies were allowed to produce oil in the country. A public bid tender was expected at presstime last week.

Not Available

1992-12-07

42

Repblica Bolivariana de Venezuela Consejo Nacional de Universidades  

E-print Network

1 República Bolivariana de Venezuela Consejo Nacional de Universidades Núcleo de Vice requerida para una función determinada. #12;2 República Bolivariana de Venezuela Consejo Nacional de mundo tecnologizado y globalizado que habitamos. " #12;3 República Bolivariana de Venezuela Consejo

Vásquez, Carlos

43

Original article Honey production in Venezuela: effects of feeding  

E-print Network

Original article Honey production in Venezuela: effects of feeding sugar syrup on colony weight to the nectar flow was studied through a complete honey production sea- son in Venezuela. A significant honeybee / European honeybee / feeding / honey production / Venezuela INTRODUCTION Feeding honey bee

Paris-Sud XI, Université de

44

Sir --Venezuela has entered 2003 deadlocked in a dangerous political  

E-print Network

Sir -- Venezuela has entered 2003 deadlocked in a dangerous political confrontation and a general to preserve Venezuela's science and its natural environment, which is rich in biodiversity. We ask for Scientific Research, PO Box 21827, Caracas 1020A, Venezuela correspondence NATURE |VOL 421 |30 JANUARY 2003

Chapman, Clark R.

45

BROWN Y FERNNDEZ, Heliconiini de Venezuela Los Heliconiini (Lepidoptera, Nymphalidae)  

E-print Network

BROWN Y FERNÁNDEZ, Heliconiini de Venezuela 29 Los Heliconiini (Lepidoptera, Nymphalidae) de Venezuela KEITH S. BROWN, JR.* Y F. FERNÁNDEZ Y�PEZ** RESUMEN Se ilustran y presentan datos sobre variación, distribución y biología de las 42 especies y 88 subespecies de Heliconiini conocidas de Venezuela, con

Mallet, James

46

Four New Hypancistrus (Siluriformes: Loricariidae) from Amazonas, Venezuela  

E-print Network

Four New Hypancistrus (Siluriformes: Loricariidae) from Amazonas, Venezuela JONATHAN W. ARMBRUSTER. lunaorum are described based on specimens from the upper Ri´o Orinoco of southern Venezuela. Hypancistrus la base de especi´menes provenientes de la cuenca alta del ri´o Orinoco en el sur de Venezuela

Armbruster, Jonathan W.

47

Mapa Geologico de Venezuela a Escala 1:750,000  

USGS Publications Warehouse

Se presenta un mapa geologico digital de Venezuela sobre un fondo de relieve sombreado. Los datos geologicos e hidrologicos del norte del rio Orinoco proceden de la digitalizacion de mapas geologicos en papel a escala 1:500.000. Estos datos fueron integrados con el mapa geologico digital del Escudo de Guayana Venezolano, a su vez derivado de hojas en papel a escala 1:500.000. La informacion sobre los tipos de fallas mostrados en el mapa es igual que en las fuentes originales. Los poligonos geologicos fueron atribuidos por edad, litologia y nombre de la unidad siguiendo el Codigo geologico de Venezuela. Se incorporaron revisiones significativas de la geologia de la Cordillera de la Costa a partir de las nuevas hojas integradas a escala 1:25.000. Toda esta informacion geologico-estructural se sobrepuso a una imagen de relieve sombreado, producida por el procesamiento de los datos de radar interferometrico con 90 m (3 arcosegundos) de resolucion espacial obtenidos por la mision topografica de radar del transbordador espacial (SRTM). Las areas de la base de datos del SRTM carentes de informacion fueron llenadas por medio de la interpolacion de los datos de las celdas adyacentes. Para producir la imagen de relieve sombreado se uso una direccion de iluminacion de 315 deg con un angulo de 65 deg sobre el horizonte. La proyeccion usada en el mapa es conica equidistante, con latitudes de 4 y 9 deg norte como paralelos estandar y una longitud de 66 deg al oeste como meridiano central. Los datos en el mapa proceden primordialment de hojas a escala 1:500.000 y el producto esta preparado para una impresion optima en escala 1:750.000. Los usuarios pueden obtener ampliaciones mayores, sin embargo no se garantiza la precision del mapa a escalas mas detalladas. Especialmente en la region de Guayana, al sobreponer los mapas geologicos sobre la reciente imagen SRTM, se notan grandes discrepancias no sistematicas tanto en contactos como en fallas. Esto es debido a que los mapas geologicos de Guayana tienen como base topografica las imagenes de radar de vision lateral (SLAR), con muy control de campo de los a?os 1970's. La correccion de estos desfases esta planificada para el futuro.

Hackley, Paul C.; Urbani, Franco; Karlsen, Alex W.; Garrity, Christopher P.

2006-01-01

48

Mastery: A Lesson from Maria in Venezuela  

ERIC Educational Resources Information Center

Children who have been born into poverty or into at-risk circumstances are often considered "disposable" and not a societal priority. These youngsters have few advocates and limited successful options in life. In the city of Maracaibo, Venezuela, there is a large population of Amerindians who are called Guajiros. These indigenous people have…

Powell, Sandra Anez; Powell, Norman W.

2012-01-01

49

Venezuela natural gas for vehicles project  

SciTech Connect

The Natural Gas for Vehicles (NGV) Project in Venezuela describes the development and growth of the NGV project in the country. Venezuela is a prolific oil producer with advanced exploration, production, refining and solid marketing infrastructure. Gas production is 5.2 Bscfd. The Venezuelan Government and the oil state owned company Petroleos de Venezuela (PDVSA), pursued the opportunity of using natural gas for vehicles based on the huge amounts of gas reserves present and produced every day associated with the oil production. A nationwide gas pipeline network crosses the country from south to west reaching the most important cities and serving domestic and industrial purposes but there are no facilities to process or export liquefied natural gas. NGV has been introduced gradually in Venezuela over the last eight years by PDVSA. One hundred forty-five NGV stations have been installed and another 25 are under construction. Work done comprises displacement or relocation of existing gasoline equipment, civil work, installation and commissioning of equipment. The acceptance and usage of the NGV system is reflected in the more than 17,000 vehicles that have been converted to date using the equivalent of 2,000 bbl oil/day.

Marsicobetre, D.; Molero, T. [Corpoven S.A., Miami, FL (United States)

1998-12-31

50

First case of human latrodectism in Venezuela.  

PubMed

The first case of envenoming by Latrodectus geometricus in Venezuela is described. The accident occurred at the victims home, in Aragua de Barcelona, Anzoátegui State. The 31-year-old female victim was bitten twice on the left scapular region, in quick succession (within seconds). She developed a hyperactive state of the central, autonomic and peripheral nervous systems with minor local symptoms. PMID:18545846

Kiriakos, Demetrio; Núñez, Paola; Parababire, Yasmely; García, Marianne; Medina, Jenny; Sousa, Leonardo De

2008-01-01

51

The history of aeronautical medicine in Venezuela  

NASA Technical Reports Server (NTRS)

The Aerial Medical Service of the Ministry of Transportation and Communications of Venezuela was created on June 1949, and later became the Department of Aeronautical Medicine. Its functions include the medical examinations of future pilots, navigators and flight engineers. The importance of good mental and physical health in all flight and ground personnel to ensure the safety of air travel is discussed.

Iriarte, D. R.

1986-01-01

52

Organo de VENEZUELA ESPERANTO-ASOCIO 33-a Jaro = N. 77 = 2-a Semestro 2005  

E-print Network

VENEZUELA STELO Organo de VENEZUELA ESPERANTO-ASOCIO 33-a Jaro = N. 77 = 2-a Semestro 2005 ISSN venezuela kulturo, historio kaj idiosinkrazio (Venezuela Esperanto-Asocio, Caracas, 1975); b) La traduko de L A Apartado 47675, Caracas 1041 ­ A http://www.esperanto-ve.org esperanto-en-venezuela

Sirvent, Víctor F.

53

Venezuela: A Study of the Educational System of Venezuela and a Guide to the Academic Placement of Students from Venezuela in Educational Institutions of the United States.  

ERIC Educational Resources Information Center

Written as a guide to be used in the admission and placement of Venezuelan students in U.S. institutions of higher education, this study discusses the education system of Venezuela. The role of education in modern Venezuela and the educational structure are summarized. Information is provided on preschool and primary education, intermediate…

Hoover, Gary

54

Le Venezuela en un clin d'oeil !  

E-print Network

Le Venezuela en un clin d'oeil ! Vie scolaire CALENDRIER UNIVERSITAIRE Peut varier d votre session à l'Université de Montréal. SYST�ME D'ENSEIGNEMENT Québec Venezuela Baccalauréat. Le Venezuela étant un pays limitrophe à la Colombie, le thème de la sécurité est un sujet important à

Charette, André

55

REPBLICA BOLIVARIANA DE VENEZUELA Consejo Nacional de Universidades  

E-print Network

REP�BLICA BOLIVARIANA DE VENEZUELA Consejo Nacional de Universidades Núcleo de Autoridades de Instituciones de Educación Universitaria de Venezuela (NAEX), reunido en sesión Ordinaria en la sede de la Dirección de Extensión de la Universidad Central de Venezuela en la ciudad de Caracas el día 15 de mayo de

Vásquez, Carlos

56

Study Abroad in Venezuela ON-SITE GUIDE 201415  

E-print Network

Study Abroad in Venezuela ON-SITE GUIDE 2014­15 S T U D Y A B R O A D THE AMERICAS #12;2 Important and can contact the on-site director if needed. In Venezuela VENUSA College 49-49 Avenida Urdaneta Edificio Guilam Mérida, Venezuela Phone: 58.274.263.7631 Fax: 58.274.263.3525 www

Weiblen, George D

57

Study Abroad in Venezuela ON-SITE GUIDE 201415  

E-print Network

Study Abroad in Venezuela ON-SITE GUIDE 2014­15 S T U D Y A B R O A D THE AMERICAS #12;2 Important and can contact the on-site director if needed. In Venezuela VENUSA College 49-49 Avenida Urdaneta Edificio Guilam Mérida, Venezuela Phone: 58.274.263.7631 Fax: 58.274.263.3525 www.VENUSAcollege.org Francy

Minnesota, University of

58

Plans to revive oil fields in Venezuela on track  

SciTech Connect

This paper reports on the three operating units of Venezuela's state owned oil company Petroleos de Venezuela SA which will begin receiving bids Feb. 28 from companies interested in operating 55 inactive oil fields in nine producing areas of Venezuela. Francisco Pradas, Pdvsa executive in charge of the program, the the company expects 88 companies or combines of foreign and domestic private companies to participate in the bidding. The program, announced last year, aims to reactivate production in marginal oil fields. It will involve the first direct participation by private companies in Venezuela's oil production since nationalization in 1976.

Not Available

1992-02-24

59

78 FR 9034 - Silicomanganese From India, Kazakhstan, and Venezuela: Final Results of the Expedited Second...  

Federal Register 2010, 2011, 2012, 2013, 2014

...A-307-820] Silicomanganese From India, Kazakhstan, and Venezuela: Final Results...antidumping duty orders on silicomanganese from India, Kazakhstan, and Venezuela. The Department...antidumping duty orders on silicomanganese from India, Kazakhstan, and Venezuela were...

2013-02-07

60

78 FR 60846 - Silicomanganese From India, Kazakhstan, and Venezuela: Continuation of Antidumping Duty Orders  

Federal Register 2010, 2011, 2012, 2013, 2014

...A-307-820] Silicomanganese From India, Kazakhstan, and Venezuela: Continuation...antidumping duty orders on silicomanganese from India, Kazakhstan, and Venezuela would likely...antidumping duty orders on silicomanganese from India, Kazakhstan, and Venezuela,...

2013-10-02

61

77 FR 59970 - Silicomanganese From India, Kazakhstan, and Venezuela; Institution of Five-Year Reviews...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Silicomanganese From India, Kazakhstan, and Venezuela; Institution of Five-Year Reviews...Silicomanganese From India, Kazakhstan, and Venezuela AGENCY: United States International...silicomanganese from India, Kazakhstan, and Venezuela would be likely to lead to...

2012-10-01

62

78 FR 13380 - Silicomanganese From India, Kazakhstan, and Venezuela; Scheduling of Full Five-Year Reviews...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Silicomanganese From India, Kazakhstan, and Venezuela; Scheduling of Full Five-Year Reviews...Silicomanganese From India, Kazakhstan, and Venezuela AGENCY: United States International...silicomanganese from India, Kazakhstan, and Venezuela would be likely to lead to...

2013-02-27

63

78 FR 4437 - Silicomanganese From India, Kazakhstan, Venezuela: Notice of Commission Determination To Conduct...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Silicomanganese From India, Kazakhstan, Venezuela: Notice of Commission Determination...silicomanganese from India, Kazakhstan, and Venezuela would be likely to lead to continuation...to the review on subject imports from Venezuela was adequate, and [[Page...

2013-01-22

64

Trypanosoma evansi in capybara from Venezuela.  

PubMed

During the slaughtering season of February and March 1991, 559 capybaras (Hydrochoerus hydrochaeris) were tested for Trypanosoma evansi in two areas in Venezuela: El Frio Ranch and El Cedral Ranch. Blood and serum samples were evaluated for T. evansi. Forty-eight (9%) of 559 capybaras had T. evansi using the microcentrifugation technique. Further, 279 (50%) of the 559 capybaras had antibodies against T. evansi immunofluorescence test in both ranches. Thus, capybaras may be important in the epizootiology of T. evansi in this enzootic area. PMID:9131577

Arias, J F; García, F; Rivera, M; López, R

1997-04-01

65

e-Science perspectives in Venezuela  

E-print Network

We describe the e-Science strategy in Venezuela, in particular initiatives by the Centro Nacional de Calculo Cientifico Universidad de Los Andes (CECALCULA), Merida, the Universidad de Los Andes (ULA), Merida, and the Instituto Venezolano de Investigaciones Cientificas (IVIC), Caracas. We present the plans for the Venezuelan Academic Grid and the current status of Grid ULA supported by Internet2. We show different web-based scientific applications that are being developed in quantum chemistry, atomic physics, structural damage analysis, biomedicine and bioclimate within the framework of the E-Infrastructure shared between Europe and Latin America (EELA)

Díaz, G; Hamar, V; Hoeger, H; Mendoza, C; Mendez, Z; Núñez, L A; Ruiz, N; Torrens, R; Uzcategui, M

2008-01-01

66

Using the Five Themes of Geography to Teach about Venezuela.  

ERIC Educational Resources Information Center

Maintains that Venezuela has many U.S. ties because of its relative proximity and economic significance. Asserts that the Five Themes of Geography can be used to design effective classroom lessons about Venezuela. Presents five activities that include student objectives, necessary materials, and step-by-step instructional procedures. (CFR)

Sunal, Cynthia Szymanski; And Others

1995-01-01

67

Critical Pedagogy and Empowering in Teacher Education in Venezuela.  

ERIC Educational Resources Information Center

This paper addresses the issue of the relationship between critical pedagogy and English as a foreign language (EFL) in Venezuela. Teacher-researchers have come to see the issues confronting nonnative educators in ELT as a more important issue than in previous years. They are particularly concerned about the current situation in Venezuela

Chacon, Carmen T.; Alvarez, Luisa Cristina

68

View of the Caribbean coast of Venezuela  

NASA Technical Reports Server (NTRS)

A near vertical view of the Caribbean coast of Venezuela is seen in this Skylab 3 Earth Resources Experiment Package S190-B (five-inch earth terrain camera) photograph taken from the Skylab space station in Earth orbit. The large body of water is the Golfo de Venezuela; and the major land mass is the Peninsula de Paraguana. The view is looking northward from the mouth of the Golfete de Coro and Punta Cardon to Punta Macolia. The peninsula is connected to the Venezuelan mainland by the narrow strip of land in the most easterly corner of the picture. The dry, arid climate of the peninsula is indicated by sparse vegetation and the abundance of sand dunes. The highest point is about 2,700 feet above the sea and is the conspicuous black spot. Old raised shorelines features appear as streaks parallel to the Golfete de Coro. Water of the Golfete de Coro is red from the high sediment content. The streaks in the water off the peninsula is apparently an effect of wind which is blowing sand and w

1973-01-01

69

Occurrence of methylmercury in Lake Valencia, Venezuela  

SciTech Connect

The presence of mercury in the environment has received renewed attention during recent years. This is in part due to the known human health and ecological effects of the highly toxic organomercury compounds, and to the fact that novel and improved analytical techniques such as atomic fluorescence spectroscopy (AFS) and capillary chromatography with AFS detection, have enhanced significantly the detection of trace amounts of mercury and organo mercurials in environmental samples. Such techniques have allowed for a better understanding of the biogeochemical cycle of mercury in the aquatic environment. This paper reports on the presence of methylmercury in the water column and sediments of a hyper-eutrophic lake. Lake Valencia is a freshwater lake located in North-Central Venezuela`s Aragua Valley. The lake`s surface area covers approximately 350 km{sup 2}, with a mean depth of 19 m and a maximum depth of 41 m. Due to the discharge of waste waters from the cities of Maracay and Valencia, as well as from other smaller villages and agricultural areas in its watershed, Lake Valencia has become hyper-eutrophic. The population of phytoplankton, particularly of blue-green algae, has increased dramatically during the last two decades resulting in anoxic conditions in the lower part of the water column during most of the year. In addition, concentrations of anthropogenic chemicals, including heavy metals, have increased in the Lake during the last four decades. 15 refs., 2 figs.

Jaffe, R.; Cai, Y.; West-Thomas, J. [Florida International Univ., Miami, FL (United States)] [and others

1997-12-31

70

[Karyotyping of Holochilus venezuelae (Rodentia, Cricetidae)].  

PubMed

We studied the cariotype of Holochilus venezuelae from 28 individuals (14 males and 14 females). Chromosome preparations were obtained by applying colchicine to live animals, followed by hypotonic shock, acetic methanol fixation and Giemsa staining of bone marrow cells. Metaphase configurations were photographed with a M-20 Wild automatic photomicroscope, and 10 karyotype from each animal were prepared from enlarged prints. Idiograms were calculated from the mean length of each chromosome pair and expressed as percentage of the length of the haploid autosome set plus one X chromosome. Results indicate the presence of six karyomorphs and the most frequent karyotype, considered basic for the species, was 2n = 44 (NF = 56), which consists of seven pairs of metacentric chromosomes (five large, one small and one microchromosome), comprising 59.5% of the haplid set; fourteen acrocentric pairs (nine small and five microchromosomes) representing 32.0% of the set; and the sexual pair, which is acrocentric, represent 6% (X) and 2.5% (Y) of the haploid set. The chromosome polymorphisms can be interpreted as the result of Robertsonian changes (fusion) and from the presence of accessory chromosomes (supernumerary). The karyotypical characteristics of the population sample studied suggest the existence of reproductive isolation through chromosomal hybrid sterility with H. brasiliensis (2n = 56 and 2n = 50), which means that H. venezuelae can be considered an allospecie. PMID:2701257

Aguilera, M; Pérez-Zapata, A

1989-01-01

71

e-Science initiatives in Venezuela  

E-print Network

Within the context of the nascent e-Science infrastructure in Venezuela, we describe several web-based scientific applications developed at the Centro Nacional de Calculo Cientifico Universidad de Los Andes (CeCalCULA), Merida, and at the Instituto Venezolano de Investigaciones Cientificas (IVIC), Caracas. The different strategies that have been followed for implementing quantum chemistry and atomic physics applications are presented. We also briefly discuss a damage portal based on dynamic, nonlinear, finite elements of lumped damage mechanics and a biomedical portal developed within the framework of the \\textit{E-Infrastructure shared between Europe and Latin America} (EELA) initiative for searching common sequences and inferring their functions in parasitic diseases such as leishmaniasis, chagas and malaria.

Chaves, J L; Hamar, V; Isea, R; Rojas, F; Ruiz, N; Torrens, R; Uzcategui, M; Florez-Lopez, J; Hoeger, H; Mendoza, C; Núñez, L A

2007-01-01

72

Digital shaded-relief map of Venezuela  

USGS Publications Warehouse

The Digital Shaded-Relief Map of Venezuela is a composite of more than 20 tiles of 90 meter (3 arc second) pixel resolution elevation data, captured during the Shuttle Radar Topography Mission (SRTM) in February 2000. The SRTM, a joint project between the National Geospatial-Intelligence Agency (NGA) and the National Aeronautics and Space Administration (NASA), provides the most accurate and comprehensive international digital elevation dataset ever assembled. The 10-day flight mission aboard the U.S. Space Shuttle Endeavour obtained elevation data for about 80% of the world's landmass at 3-5 meter pixel resolution through the use of synthetic aperture radar (SAR) technology. SAR is desirable because it acquires data along continuous swaths, maintaining data consistency across large areas, independent of cloud cover. Swaths were captured at an altitude of 230 km, and are approximately 225 km wide with varying lengths. Rendering of the shaded-relief image required editing of the raw elevation data to remove numerous holes and anomalously high and low values inherent in the dataset. Customized ArcInfo Arc Macro Language (AML) scripts were written to interpolate areas of null values and generalize irregular elevation spikes and wells. Coastlines and major water bodies used as a clipping mask were extracted from 1:500,000-scale geologic maps of Venezuela (Bellizzia and others, 1976). The shaded-relief image was rendered with an illumination azimuth of 315? and an altitude of 65?. A vertical exaggeration of 2X was applied to the image to enhance land-surface features. Image post-processing techniques were accomplished using conventional desktop imaging software.

Garrity, Christopher P.; Hackley, Paul C.; Urbani, Franco

2004-01-01

73

Tax effects upon oil field development in Venezuela  

E-print Network

Important reforms have been made to the oil sector tax code in Venezuela. Given its diversity of oil resources, there was a concern that some resources were not being exploited because of the structure of the tax code. ...

Manzano, Osmel

2000-01-01

74

A reservoir management strategy for multilayered reservoirs in eastern Venezuela  

E-print Network

A reservoir management strategy has been developed for a field located in eastern Venezuela. The field contains deep, high pressure, multilayer reservoirs. A thorough formation evaluation was accomplished using the log data, core data, PVT data...

Espinel Diaz, Arnaldo Leopoldo

2012-06-07

75

Hydrogen: BOC-FW venture secures major Venezuela project  

SciTech Connect

BOC Gases and Foster Wheeler Power Systems (FW) have been awarded a $50-million project to supply a 50-million cu ft/day hydrogen (H{sub 2}) plant to Lagoven`s Amuay, Venezuela refinery for 1997 startup. BOC and FW have also formed a marketing agreement for on-site H{sub 2} plants in the Americas, extending a previous relationship covering Chile and Venezuela.

Wood, A.

1995-07-26

76

Morphological characters of adult Anopheles (Nyssorhynchus) marajoara in Venezuela.  

PubMed

A morphometric study was carried out to find diagnostic characters with which to update taxonomic keys for field identification of Anopheles (Nyssorhynchus) marajoara and the 3 other sympatric Anopheles (Nyssorhynchus) species (An. darlingi, An. argyritarsis, and An. braziliensis) that occur in Venezuela. Diagnostic random amplified polymorphic DNA-polymerase chain reaction markers from wild-caught specimens showed that An. marajoara was the only species in the Anopheles albitarsis complex collected in Venezuela. PMID:12825659

Rubio-Palis, Yasmin; Wilkerson, Richard; Guzmán, Hernán

2003-06-01

77

Petroleum resources of Venezuela and Trinidad and Tobago  

SciTech Connect

The status of known and ultimately recoverable crude oil and natural gas resources of the Federal Republics of Venezuela, and Trinidad and Tobago (hereafter referred to as Trinidad) is set forth in this report. The rates that oil resources may be available to world markets are also covered in the report. A section on the petroleum geology of the region is included. The Republics of Venezuela and Trinidad share a common and ancient petroleum history. Over a century of exploration and development have resulted in the cumulative production of nearly 39 billion barrels of oil from Venezuela and over 2 billion barrels from Trinidad. Both republics have passed their peak status as oil producers. Venezuela reached its peak as the second largest producer in the world in the mid-fifties, and Trinidad attained its highest status as the eighth largest oil producer in the early forties. The report concludes that Venezuela and Trinidad have depleted slightly less than one-half of their ultimately recoverable crude oil resources. Based on feasible production rates and estimates of remaining recoverable resources, nearly two-thirds of Venezuela's oil resources and about three-fourths of Trinidad's oil resources may be depleted by the year 2000. The natural gas resources of both countries are underutilized and underdeveloped.

Not Available

1983-07-01

78

TUBERCULOSIS COMO ENFERMEDAD OCUPACIONAL  

PubMed Central

Existe evidencia suficiente para declarar a la tuberculosis como enfermedad ocupacional en diversos profesionales especialmente entre los trabajadores de salud. En el Perú están normados y reglamentados los derechos laborales inherentes a la tuberculosis como enfermedad ocupacional, como la cobertura por discapacidad temporal o permanente. Sin embargo, estos derechos aún no han sido suficientemente socializados. En este trabajo se presenta información sobre el riesgo de adquirir tuberculosis en el lugar de trabajo, se revisan las evidencias para declarar a la tuberculosis como enfermedad ocupacional en trabajadores de salud y se presenta la legislación peruana vigente al respecto. PMID:22858771

Mendoza-Ticona, Alberto

2014-01-01

79

[Highest mosquito records (Diptera: Culicidae) in Venezuela].  

PubMed

Mosquitoes (Diptera: Culicidae) are holometabolous insects with aquatic immature stages, which use a broad variety of larval habitats, from ground water bodies to Phytothelmata (water deposits in plants) and artificial deposits. The availability of breeding sites often determines the upper limits of mosquito ranges. We built a database with 9,607 records with 432 localities, 19 genera and 254 species. The Andean mountains have 77% of the highest mosquito records including Aedes euris with record at 3,133 m, followed by three species of Anopheles--subgenera Kerteszia--with the upper limit of 2,680 m. Wyeomyia bicornis and Culex daumastocampa at 2,550 m were the highest records in the Central-Coastal cordillera, while the highest record in Pantepui was Wyeomyia zinzala at 2,252 m. The species associated with phytothelmata (Bromeliaceae and Sarraceniaceae) represent 60% of the records. The upper limits of Culex quinquefasciatus and Anopheles (Kerteszia) species could represent the theoretical limit for transmission of filariasis or arboviruses, by Culex, and malaria by Anopheles (Kerteszia) in Venezuela. Similarly, a vector of Dengue, Aedes aegypti, has not been not recorded above 2,000 m. PMID:20411719

Navarro, Juan-Carlos; Del Ventura, Fabiola; Zorrilla, Adriana; Liria, Jonathan

2010-03-01

80

Atmospheric formic and acetic acids in Venezuela  

NASA Astrophysics Data System (ADS)

Gas, phase and rain concentrations of HCOOH and CH 3COOH have been measured at various sites in the savannah climatic region, a cloud forest site and a coastal site in Venezuela. Gas phase and rain water were sampled using the aqueous scrubber technique and a wet only collector, respectively. Analyses were made by ion chromatography. The results indicate that formic and acetic acids are important components of the Venezuelan atmosphere. They are homogeneously distributed, suggesting a widespread source. Boundary layer concentrations during the dry season (HCOOH, 1.8 ppbv; CH 3COOH, 1.25 ppbv) are higher than in the wet season (HCOOH, 1.0 ppbv; CH 3COOH, 0.7 ppbv), mainly due to a longer lifetime of the acid during the dry season (˜6 days) compared with the wet season (˜2 days). The overall concentrations in rain are 7.0 and 4.0 ?M for formic and acetic acids, respectively. The estimated annual total depositions are: HCOOH, 17 mmol m -2 yr -1 and CH 3COOH,10 mmol m -2 yr -1; around half of the acids are removed by dry deposition. It is established that a larger source (˜1.8 times) of both acids is present during the wet season. We speculate that atmospheric oxidation of hydrocarbons should be the main source of HCOOH and CH 3COOH in the Venezuelan atmosphere; soil emissions could make a significant contribution during the dry season.

Sanhueza, Eugenio; Figueroa, Luis; Santana, Magaly

81

Malaria Control and Elimination,1 Venezuela, 1800s–1970s  

PubMed Central

Venezuela had the highest number of human malaria cases in Latin American before 1936. During 1891–1920, malaria was endemic to >600,000 km2 of this country; malaria death rates led to major population decreases during 1891–1920. No pathogen, including the influenza virus that caused the 1918 pandemic, caused more deaths than malaria during 1905–1945. Early reports of malaria eradication in Venezuela helped spark the world’s interest in global eradication. We describe early approaches to malaria epidemiology in Venezuela and how this country developed an efficient control program and an approach to eradication. Arnoldo Gabaldón was a key policy maker during this development process. He directed malaria control in Venezuela from the late 1930s to the end of the 1970s and contributed to malaria program planning of the World Health Organization. We discuss how his efforts helped reduce the incidence of malaria in Venezuela and how his approach diverged from World Health Organization guidelines.

Villegas, Leopoldo; Udhayakumar, Venkatachalam

2014-01-01

82

Malaria control and elimination, Venezuela, 1800s –1970s.  

PubMed

Venezuela had the highest number of human malaria cases in Latin American before 1936. During 1891–1920,malaria was endemic to >600,000 km2 of this country; malaria death rates led to major population decreases during 1891–1920. No pathogen, including the influenza virus that caused the 1918 pandemic, caused more deaths than malaria during 1905–1945. Early reports of malaria eradication in Venezuela helped spark the world's interest in global eradication. We describe early approaches to malaria epidemiology in Venezuela and how this country developed an efficient control program and an approach to eradication.Arnoldo Gabaldón was a key policy maker during this development process. He directed malaria control in Venezuela from the late 1930s to the end of the 1970s and contributed to malaria program planning of the World Health Organization.We discuss how his efforts helped reduce the incidence of malaria in Venezuela and how his approach diverged from World Health Organization guidelines. PMID:25396258

Griffing, Sean M; Villegas, Leopoldo; Udhayakumar, Venkatachalam

2014-10-01

83

Importancia de la gestión de la cultura corporativa en procesos de certificación de calidad  

Microsoft Academic Search

El presente trabajo busca aportar conocimientos en relación con la importancia dada a la cultura corporativa y al esquema de gestión utilizado en el manejo de los cambios derivados de la implantación de procesos de certificación de calidad, y de acuerdo con los conocimientos, apreciaciones y experiencia de 25 asesores y consultores de empresas en Sistemas de Gestión de la

Olga Lucía Anzola Morales

84

David Meets Goliath on the Information Superhighway: Venezuela in the Context of the Electronic Communication Networks.  

ERIC Educational Resources Information Center

Discusses Venezuela's information and communications technology infrastructure and usage patterns; examines future networking plans; and addresses political and economic considerations linked to the information and technology problems in Venezuela and in Latin America in general. (LRW)

Sanchez-Vegas, Saadia

1995-01-01

85

78 FR 44969 - Ferrosilicon From Russia and Venezuela; Institution of Antidumping Duty Investigations and...  

Federal Register 2010, 2011, 2012, 2013, 2014

...731-TA-1224-1225 (Preliminary)] Ferrosilicon From Russia and Venezuela; Institution of Antidumping Duty Investigations and Scheduling...materially retarded, by reason of imports from Russia and Venezuela of Ferrosilicon, provided for in subheadings...

2013-07-25

86

Molecular architecture of DesV from Streptomyces venezuelae: A PLP-dependent transaminase involved in  

E-print Network

Molecular architecture of DesV from Streptomyces venezuelae: A PLP-dependent transaminase involved are required for its biosynthesis in Streptomyces venezuelae. The focus of this article is DesV, which

Holden, Hazel

87

Accelerated Publications Three-Dimensional Structure of DesVI from Streptomyces Venezuelae: A Sugar  

E-print Network

Accelerated Publications Three-Dimensional Structure of DesVI from Streptomyces Venezuelae: A Sugar for the biosynthesis of dTDP-desosamine in Streptomyces Venezuelae, with the last step catalyzed by DesVI, an N

Holden, Hazel

88

Syllidae (Annelida, Polychaeta) from the Caribbean coast of Venezuela  

PubMed Central

Abstract Venezuela possesses a great variety of coastal environments allowing for a high diversity of marine species. However, systematic studies on marine invertebrates are scarce, especially on polychaetes. The family Syllidae is poorly known, and only 14 genera and 42 species have been reported from this country. A total of 13 genera and 26 species the Syllidae were identified from benthic samples collected on different substrata of the northeastern coast of Venezuela. Of these, seven genera and 16 species constitute new records for Venezuela: Odontosyllis guillermoi, Syllides floridanus, Salvatoria clavata, Salvatoria limbata, Sphaerosyllis longicauda, Parapionosyllis longicirrata, Trypanosyllis parvidentata, Trypanosyllis vittigera, Opisthosyllis sp., Syllis amica, Syllis armillaris, Syllis gracilis, Syllis pseudoarmillaris, Syllis vittata, Parasphaerosyllis indica and Myrianida convoluta. PMID:21998503

Liñero-Arana, Ildefonso; Díaz Díaz, Oscarn

2011-01-01

89

Digital geologic map and GIS database of Venezuela  

USGS Publications Warehouse

The digital geologic map and GIS database of Venezuela captures GIS compatible geologic and hydrologic data from the 'Geologic Shaded Relief Map of Venezuela,' which was released online as U.S. Geological Survey Open-File Report 2005-1038. Digital datasets and corresponding metadata files are stored in ESRI geodatabase format; accessible via ArcGIS 9.X. Feature classes in the geodatabase include geologic unit polygons, open water polygons, coincident geologic unit linework (contacts, faults, etc.) and non-coincident geologic unit linework (folds, drainage networks, etc.). Geologic unit polygon data were attributed for age, name, and lithologic type following the Lexico Estratigrafico de Venezuela. All digital datasets were captured from source data at 1:750,000. Although users may view and analyze data at varying scales, the authors make no guarantee as to the accuracy of the data at scales larger than 1:750,000.

Garrity, Christopher P.; Hackley, Paul C.; Urbani, Franco

2006-01-01

90

Events affecting gold exploration in Venezuela since 1999  

USGS Publications Warehouse

The structure of the gold mining industry in Venezuela has changed significantly since 1999 as a result of Government policy changes and industry response to these changes. This report documents the policy decisions that have affected the mining industry, discusses the response of the industry on a site by site basis, and suggests possible effects of these changes on the global economy. For the short term, at least, it appears that these changes have made Venezuela a more difficult place to invest for U.S. and Canadian companies, while investment by Chinese entities has been encouraged.

Wilburn, David R.

2014-01-01

91

Potential role of event-driven sediment transport on sediment accumulation in the Cariaco Basin, Venezuela  

E-print Network

Basin, Venezuela Laura Lorenzoni a, , Claudia R. Benitez-Nelson b,c , Robert C. Thunell b,c , David, Venezuela e Venezuelan Foundation for Seismological Research (FUNVISIS), Apartado Postal 76880, Caracas 1070-A, Venezuela a b s t r a c ta r t i c l e i n f o Article history: Received 8 June 2011 Received

Meyers, Steven D.

92

EPIDEMIOLOGY OF BOVINE LEUKEMIA IN VENEZUELA C. MARN NANCY M. DE LPEZ LUISA ALVAREZ O. LOZANO  

E-print Network

EPIDEMIOLOGY OF BOVINE LEUKEMIA IN VENEZUELA C. MARÍN NANCY M. DE L�PEZ LUISA ALVAREZ O. LOZANO W. ESPANA H. CASTA�OS A. LE�N '! Instltuto de Investigaciones Veterinarias, Apartado 70. Maracay. Venezuela. R6sum6 EPIDEMIOLOGIE DE LA LEUCOSE BOVINE AU VENEZUELA. - Environ 20 000 bovins de races autochtones

Paris-Sud XI, Université de

93

Ingeniero Diana Awais GACETA OFICIAL DE LA REPBLICA BOLIVARIANA DE VENEZUELA  

E-print Network

Ingeniero Diana Awais GACETA OFICIAL DE LA REP�BLICA BOLIVARIANA DE VENEZUELA A�O CXXX-MES IX Funcional, que en ella se especifican. REP�BLICA BOLIVARIANA DE VENEZUELA CONSEJO NACIONAL DE UNIVERSIDADES de la República Bolivariana de Venezuela, introduce innovaciones en el campo jurídico

Vásquez, Carlos

94

Quantifying the seasonal variations in fluvial and eolian sources of terrigenous material to Cariaco Basin, Venezuela  

E-print Network

to Cariaco Basin, Venezuela Aurora C. Elmore a,*, Robert C. Thunell b , Richard Styles b , David Black c, Venezuela a r t i c l e i n f o Article history: Received 27 February 2008 Accepted 10 November 2008 the northern continental shelf of Venezuela and consists of two 1400 m deep sub-basins separated by an 900 m

Meyers, Steven D.

95

Receiver function study of the crustal structure of the southeastern Caribbean plate boundary and Venezuela  

E-print Network

and Venezuela Fenglin Niu,1 Tammy Bravo,2 Gary Pavlis,2 Frank Vernon,3 Herbert Rendon,4 Maximiliano Bezada,1 broadband array deployed under the BOLIVAR project and the permanent national seismic network of Venezuela northeastern Venezuela and the Venezuelan Andes. There is a good correlation between crustal structure

Niu, Fenglin

96

Mantle flow beneath northwestern Venezuela: Seismic evidence for a deep origin of the Mrida Andes  

E-print Network

Mantle flow beneath northwestern Venezuela: Seismic evidence for a deep origin of the Mérida Andes University, Houston, TX, USA b Fundación de Investigaciones Simológicas (FUNVISIS), Caracas, Venezuela a b wave splitting from SKS data recorded by the national seismic network of Venezuela and a linear

Niu, Fenglin

97

NATURAL HAZARDS ON ALLUVIAL FANS: THE VENEZUELA DEBRIS FLOW AND FLASH FLOOD DISASTER  

E-print Network

NATURAL HAZARDS ON ALLUVIAL FANS: THE VENEZUELA DEBRIS FLOW AND FLASH FLOOD DISASTER In December Venezuela. Rainfall on December 2-3 totaled 200 millimeters (8 inches) and was followed by a major storm, Denver, Colorado, Naples, Italy, and Vargas, Venezuela. In time scales spanning thousands of years

Eaton, L. Scott

98

Nitrogen isotope dynamics of the Cariaco Basin, Venezuela Robert C. Thunell,1  

E-print Network

Nitrogen isotope dynamics of the Cariaco Basin, Venezuela Robert C. Thunell,1 Daniel M. Sigman,2 of Venezuela. Water column denitrification occurring in the basin has only a very small isotopic imprint-Karger, Y. Astor, and R. Varela (2004), Nitrogen isotope dynamics of the Cariaco Basin, Venezuela, Global

Sigman, Daniel M.

99

POTENTIAL EFFECTS OF GLOBAL CLIMATIC CHANGE ON THE PHENOLOGY AND YIELD OF MAIZE IN VENEZUELA *  

E-print Network

POTENTIAL EFFECTS OF GLOBAL CLIMATIC CHANGE ON THE PHENOLOGY AND YIELD OF MAIZE IN VENEZUELA de Ciencias, Universidad de Los Andes, Mdrida 5101, Venezuela 21nstitute of Applied Sciences, Venezuela 4Centro de Estudios Avanzados del Clima Tropical (CEACT), Ministerio deI Ambiente y de los

Robock, Alan

100

Evidence for clonal propagation in natural isolates of Plasmodium falciparum from Venezuela  

E-print Network

Evidence for clonal propagation in natural isolates of Plasmodium falciparum from Venezuela Ludmel, Estado Aragua, Venezuela; Division of Parasitic Diseases, National Center for Infectious Diseases, 2001 We have analyzed 75 isolates of Plasmodium falciparum, collected in Venezuela during both the dry

101

Pathogenicity of seven species of the Botryosphaeriaceae on Eucalyptus clones in Venezuela  

E-print Network

Pathogenicity of seven species of the Botryosphaeriaceae on Eucalyptus clones in Venezuela S. R Milla, 5101-A Mérida, Venezuela. B Department of Genetics, Forestry and Agricultural Biotechnology found on Eucalyptus spp. in Venezuela. An initial inoculation trial was conducted using seven species

102

BREEDING BIOLOGY AND NATURAL HISTORY OF THE SLATE-THROATED WHITESTART IN VENEZUELA  

E-print Network

BREEDING BIOLOGY AND NATURAL HISTORY OF THE SLATE-THROATED WHITESTART IN VENEZUELA ROMA´ N A´ National Park, Venezuela. Nesting activity peaked in late April and May. Only the female built the nest is the most common race in the Andes of Venezuela, Colombia, and part of Ecuador. Genetic information for our

Martin, Thomas E.

103

MTODO DE LOCALIZACIN DE LOS HERIDOS EN EL CASO DE UN TERREMOTO EN MRIDA, VENEZUELA.  

E-print Network

M�TODO DE LOCALIZACI�N DE LOS HERIDOS EN EL CASO DE UN TERREMOTO EN M�RIDA, VENEZUELA. Methodology for the localization of injured in case of an earthquake in Mérida, Venezuela. Julien Rebotier *11 rue Duvergier 75019) julio - diciembre 2006, pp 187-200. Resumen: Mérida (Venezuela) es particularmente sensible a la amenaza

Boyer, Edmond

104

TWO NEW SPECIES OF LEPIDOCYRTUS FROM PARAMO DE MUCUBAJI MERIDA, VENEZUELA  

E-print Network

TWO NEW SPECIES OF LEPIDOCYRTUS FROM PARAMO DE MUCUBAJI MERIDA, VENEZUELA (COLLEMBOLA ejemplares colectados en Paramo de Mucubaji, Estado de Merida, Venezuela. Los individuos fueron encontrados in Venezuela but only one, L. summersii (MacGillivray) 1894, has been described or reported from this country

Mari-Mutt, José A.

105

BREEDING BIOLOGY OF THE GOLDEN-FACED TYRANNULET (ZIMMERIUS CHRYSOPS) IN VENEZUELA  

E-print Network

BREEDING BIOLOGY OF THE GOLDEN-FACED TYRANNULET (ZIMMERIUS CHRYSOPS) IN VENEZUELA WILLIAM GOULDING1 Park, Venezuela during the 2002 to 2008 breeding seasons. The enclosed nest was similar to descriptions, it is broadly distributed with a range that extends from Peru, north through the Andes to Colombia and Venezuela

Martin, Thomas E.

106

Pedernales oilfield, eastern Venezuela: The first 100 years  

SciTech Connect

Petroleum seeps and surface tar mats attracted oil explorers to Pedernales in eastern Venezuela 100 years ago. Commercial production from the Pedernales Field was established by Creole in 1933. In three production periods, broken by WWII and the end of the Creole-Texaco refining contract, Creole and Lagoven produced about 60 MMSTB from about 60 wells in about 60 years. Peak production was in the late 1950s, when the field delivered 12,000 BOPD. Production was stopped in 1986. In March 1993, BP Venezuela acquired the license to reactivate Pedernales on behalf of Lagoven, and BP`s first well in the field was drilled in August 1994. A second was completed in early 1995. The production from each well was sufficiently encouraging for commerciality to be declared in March 1995. Phase 1 of the field reactivation demanded a production rate of 11,500 BOPD. As of now (September, 1995) six wells, including one gas disposal well, have been completed. Wells have been placed using a combination of old well data and mapping based on a close spaced 2D seismic survey shot in early 1994. Results from these first few wells indicate that the required production rate will be achieved despite severely depleted reservoir pressures. This paper tells the story of reactivation and re-evaluation of one of eastern Venezuela`s oldest oilfields.

Gluyas, J.; Oliver, J.; Wilson, W. [BP Las Mercedes Caracas (Venezuela)

1996-08-01

107

Temperature, heat, and mixing in Lake Valencia, Venezuela  

Microsoft Academic Search

Abstract Water temperature profiles, weather data, and lake level data spanning a 2-year period for Lake Valencia, Venezuela (10”N, 67”W), are used in an analysis of thermal regime, mixing, ancl heat flux, The lake, which has an arca of 350 km2 and mean depth of 19 m, is warm monomictic; it becomes isothermal annually near the end of November, at

WILLIAM M. JR. LEWIS

1983-01-01

108

Genetic Characterization of Rabies Field Isolates from Venezuela  

Microsoft Academic Search

Twenty samples from cases of rabies in humans and domestic animals diagnosed in Venezuela between 1990 and 1994 and one sample from a vampire bat collected in 1976 were characterized by reactivity to monoclonal antibodiesagainsttheviralnucleoproteinandbypatternsofnucleotidesubstitutioninthenucleoproteingene. Three antigenic variants were found: 1, 3, and 5. Antigenic variant 1 included all samples from dogs and humans infected by contact with rabid dogs.

CARLOS A. DEMATTOS; CECILIA C. DEMATTOS; JEAN S. SMITH; EDITH T. MILLER; SARA PAPO; ANTONIO UTRERA; ANDBENNIE I. OSBURN

109

An investigation of rainfall variability and distribution in Venezuela  

E-print Network

'966. Grosske, F. , Sabre I a Pluviosidad en Caracas, Universidad Central De Venezuela, Facultad De Ingenieria, Depart- amento De Meteorogia e Hidrologia, 144 pp. , Marzo 1967. Henry, tI. K. , Gr if'ithes, 3- F . , Cobb, G. L. and Coligado, M. C. , "Research...

Gibson, Donald Reid

1968-01-01

110

MODIS detects oil spills in Lake Maracaibo, Venezuela  

Microsoft Academic Search

Starting December 2002, the oil industry operating in and around Lake Maracaibo in Venezuela suffered a series of accidents (Figure 1). Fires, the sinking of two barges, rupture of oil pipelines, spills from floating oil storage and transfer stations, and malfunctioning of oil extraction platforms led to extensive oil spills. Local and federal Venezuelan government oil industry experts directly observed

Chuanmin Hu; Frank E. Müller-Karger; Douglas Myhre; Brock Murch; Ana L. Odriozola; Gonzalo Godoy

2003-01-01

111

Late Pleistocene carbonate dissolution in the Venezuela Basin, Caribbean Sea  

SciTech Connect

Piston cores from water depths greater than 4000 m in the Venezuela Basin (Caribbean Sea) provide continuous late Pleistocene records of carbonate dissolution and accumulation. The authors examination of multiple dissolution indices indicate that, at least for the last 150,000 years, dissolution of carbonate in the Venezuela Basin has been more intense during interglacial than glacial periods, a pattern opposite to more general observations from the deep Atlantic and Gulf of Mexico. By virtue of its shallow sill depth (1815 m), the Venezuela Basin is relatively isolated from the mainstream of Atlantic thermohaline circulation, and presently is filled with homogeneous, relatively warm (3.8/sup 0/C) waters primarily derived from Upper North Atlantic Deep Water. During the last glacial, the enhanced preservation of carbonate in the Venezuela Basin suggests the presence of a less corrosive, more oxygenated water mass in the Atlantic near sill depth. However, this simple interpretations is potentially complicated by past changes in the rain of biogenic materials from surface waters to the deep basin in what must be an essentially closed system below sill depth. Their observations of increased interglacial dissolution may help to explain previously noted discrepancies in the local glacial to interglacial amplitude of delta/sup 18/O variations recorded by coccoliths and planktonic foraminifera.

Cofer-Shabica, N.B.; Peterson, L.C.

1985-01-01

112

Fruiting Capsule of a Pachira Species from Estado Amazonas, Venezuela  

NSDL National Science Digital Library

Fruiting capsule of a Pachira species from Estado Amazonas, Venezuela, which has been opened to show its large, floatable seeds. The seeds of other species in this genus of tropical trees are smaller and surrounded by dense, non-wettable hairs. Pachira is a member of the traditional family Bombacaceae, which like the Sterculiaceae and Tiliaceae has been found to be non-monophyletic.

Gustavo A. Romero

2004-03-09

113

Be dating of river terraces of Santo Domingo river, on Southeastern flank of the Mrida Andes, Venezuela: Tectonic and climatic  

E-print Network

, Venezuela: Tectonic and climatic implications Oswaldo Guzmán a, b, *, Riccardo Vassallo b , Franck Audemard, Caracas 1081-A, Venezuela b ISTerre, Université de Savoie, CNRS, F-73376 Le Bourget du Lac, France c, Venezuela d Escuela de Geología, Minas y Geofísica, Facultad de Ingeniería, Universidad Central de Venezuela

114

A biostratigraphic sequence analysis in Cretaceous sediments from Eastern Venezuela  

SciTech Connect

This paper presents the results of a high resolution biostratigraphic study integrated with petrophysic analyses, of the Late Cretaceous sequence in several wells from the Maturin Sub-Basin, Eastern Venezuela. The main objective of this study is to integrate the different faunal and floral assemblages to the sedimentological evolution of the basin using sequential analysis techniques. This technique was applied using mainly terrestrial and marine palynomorphs which were relatively abundant and diverse as compared to the scarcity of foraminifera and nonnofossils. Based on the percentages of abundance and the diversity of the different groups of microfoss it was possible to establish the maximum flooding surfaces and condensation levels which allowed the definition of the possible candidates for the sequence boundaries. On the other hand, the identified bioevents made possible the definition of the chronostratigraphic datums of the sequence under study. The results obtained will contribute to optimize the exploration and development programs of the oil fields in Eastern Venezuela.

Paredes, I.; Carillo, M.; Fasola, A.; Luna, F. (Intevep S.A., Caracas (Venezuela))

1993-02-01

115

Consideration of regulations of baby foods containing soybeans in Venezuela  

Microsoft Academic Search

Quality standards for industrially processed food products are being prepared by a joint committee composed of the private\\u000a sector, government and universities. These standards include specific dispositions which, if necessary, allow utilization\\u000a of different ingredients-soya protein derivatives among them- to improve the quality and quantity of the protein or to balance\\u000a the amino acid profile. Despite these efforts, in Venezuela,

J. F. Chavez

1981-01-01

116

Use of molluscicides in the control of bilharziasis in Venezuela*  

PubMed Central

The application of molluscicides to the breeding-places of Australorbis glabratus—the intermediate host of Schistosoma mansoni in Venezuela—is discussed, with special reference to the equipment required and the techniques employed. The characteristics of the three molluscicides in use—copper sulfate, sodium pentachlorophenate, and copper pentachlorophenate—are outlined, and the treatment both of running waters (irrigation canals and streams) and of still waters (ponds and marshes) is described in detail. PMID:13356139

Jove, José Antonio

1956-01-01

117

Two new Larainae species from Guayana region, Venezuela (Coleoptera: Elmidae).  

PubMed

Two new species of the subfamily Larainae (Insecta: Coleoptera: Elmidae), Hexanchorus angeli n. sp. and Hypsilara autanai n. sp., are described from Guyana region in Venezuela. We provide habitus photographs, detail drawings of both male and female genitalia, and description of morphological features important for discrimination of the new species. Molecular differences within genera were measured using 816bp fragment of mtDNA gene for cytochrome oxidase c subunit I. Sequence divergences among species are discussed. PMID:24872290

Laššová, Kristína; Ciampor, Fedor; Ciamporová-Za?ovi?ová, Zuzana

2014-01-01

118

Breeding systems in a montane tropical cloud forest in Venezuela  

Microsoft Academic Search

The breeding systems, reproductive efficacies and population densities of 75 species of trees, shrubs, perennial herbs and\\u000a vines in a montane tropical cloud forest in Venezuela are investigated. 56.96% and 44.32% of the trees, versus the other life\\u000a forms considered, respectively possess obligate outbreeding mechanisms. Two shrubs are non-pseudogamous apomicts. The percentage\\u000a of dioecy among tree species (31%) is among

Claudia Sobrevila; Mary T. Kalin Arroyo

1982-01-01

119

Risk factors for dialysis-associated hepatitis C in Venezuela  

Microsoft Academic Search

Risk factors for dialysis-associated hepatitis C in Venezuela. Utilizing the first and second generation of enzyme immunoassays which detect antibodies to the C virus we investigated the frequency of anti-HCV antibodies in 315 patients undergoing hemodialysis. Other subpopulations at risk were used as reference groups. One hundred and twenty-three samples (39%) from the hemodialysis group repeatedly showed anti-HCV positive antibodies

Grete Y Muller; Mercedes E Zabaleta; Anabella Arminio; Carmen J Colmenares; Freya I Capriles; Nicolás E Bianco; Irma V Machado

1992-01-01

120

Curie point depth in Venezuela and the Eastern Caribbean  

NASA Astrophysics Data System (ADS)

We estimate the Curie point depth (CPD) variations of Venezuela (continental crust, South American plate) and the Eastern Caribbean (oceanic crust, Caribbean Plate) by using spectral analysis of the magnetic anomalies, extracted from the 2010 Enhanced Magnetic Model (EMM2010), available at the National Oceanic and Atmospheric Administration (NOAA). To test the reliability of the spectral content of this model, for a small region, we compare he CPD derived from the EMM2010 against the one from aeromagnetic data. We also compile heat flow data from previous studies to correlate them with the CPD lateral variations. The estimations show that the CPD in Venezuela and the Eastern Caribbean ranges between 54 and 17 km. The mean depth value within the continental crust is around 38 km. On the Guayana Shield, it has a mean value of 42 km and reaches a maximum of 54 km. As the Moho depth is at most 50 km, the upper mantle beneath the craton is magnetized. Continental lateral variations appear to be linked to the isostatic state and age of the different provinces, and mark the limit between the Precambrian and the Paleozoic provinces. The Maracaibo Basin is revealed as a thermally stable one with a constant CPD, while the Eastern Venezuela Basin is thermally affected. Most of the Eastern Caribbean seems stable, with a large non-perturbed area with a mean CPD value of 23 km. As the crustal thickness is at most 20 km, the isotherm is located within the upper mantle. A CPD minimum located on the Lesser Antilles arc is concentrated in its northern part, and can be related to the subduction zone that is most active. Finally, a shallow area within the Eastern Caribbean corresponds to the thin crust region in the Venezuela Basin, although it might be linked to mantle dynamics.

Arnaiz-Rodríguez, Mariano S.; Orihuela, Nuris

2013-04-01

121

Radioisotope Concentration in Lake Sediments of Maracaibo, Venezuela  

SciTech Connect

Maracaibo Lake is one of the most important water basing and oil producing regions in Venezuela. Changes in the local environment have been monitored for chemical pollution in the past. For this study we selected a set of sediment samples collected in the shore and analyzed for its radioisotope content. Results show the gamma emitting isotopes distribution. Isotopes concentrations have been determined within the natural K, Th and U families.

Salas, A. Rangel; Viloria, T. [La Universidad del Zulia (Venezuela); Sajo-Bohus, L.; Barros, H.; Greaves, E. D.; Palacios, D. [Universidad Simon Bolivar (Venezuela)

2007-10-26

122

Late Quaternary Environmental History of Lake Valencia, Venezuela  

Microsoft Academic Search

Chemical, paleontological, and mineralogical analyses of a 7.5-meter core from the middle of Lake Valencia, Venezuela, have provided information on the paleoclimatic history of this low-elevation, low-latitude site for the last 13,000 years. The data show that dry climates existed in this region from 13,000 years before present (B.P.) until about 10,000 years B.P. The Lake Valencia Basin was occupied

J. Platt Bradbury; B. Leyden; M. Salgado-Labouriau; W. M. Lewis; C. Schubert; M. W. Binford; D. G. Frey; D. R. Whitehead; F. H. Weibezahn

1981-01-01

123

CR Mission ORENOQUE Venezuela 07 25 mars 2000  

E-print Network

CR Mission ORENOQUE Venezuela 07 ­ 25 mars 2000 Jean GUILLARD Cette mission est la première de l des zones estuariennes du delta de l'Orénoque ». Une mission exploratoire a été réalisée en octobre 99 afin de préciser les conditions d'échantillonnage (cf. CR Mission oct. 99). Ce programme est une

Guillard, Jean

124

Inventory of related wild species of priority crops in Venezuela  

Microsoft Academic Search

A prerequisite in any conservation programme of Plant Genetic Resources is estimation of diversity. The inventory of wild\\u000a and naturalized relatives of priority crops in Venezuela (CWR) is based on the main Catalogues of Flora in the country, selecting\\u000a taxa closely related to crops, according to the concepts of “gene pool” and “taxonomic group”. We included 47 genera, 217\\u000a species

Chiara BerlingeriManuel; Manuel B. Crespo

125

Paleogeographic maps, Maturin basin of east Venezuela and Trinidad  

SciTech Connect

The northern margin of the Maturin basin of east Venezuela and Trinidad is part of the Caribbean-South American plate-boundary zone, and deformation within the zone reflects relative motions of these two plates. Stratigraphic sections within this zone do not record sedimentation at a fixed site but rather the different paleogeographic locations occupied by a piece of lithosphere as it migrated through space and time. This paper presents a method of restoring stratigraphic control to its site of deposition. The method assumes a constant rate of 2 cm/yr of relative eastward motion for the Caribbean plate in the vicinity of Trinidad and a uniform distribution of shear among numerous wrench faults within the boundary zone. A compressional component is independently derived by restoring a north-northeast-south-southeast cross section through Trinidad. Lithostratigraphic reference sections from Venezuela and Trinidad are reinterpreted as a paleoshelf edge which has undergone more than 90{degree} of clockwise rotation since the middle Eocene. The buried thrust front found productive in Venezuela at El Furrial is traced eastward across Trinidad and into the offshore. Restored paleogeographic maps are presented for middle Pliocene (3 m.y.); middle Miocene (14 m.y.); the Oligocene-Miocene boundary (22 m.y.) and middle Eocene (45 m.y.).

Rohr, G.M.

1990-05-01

126

Venezuela recasts itself as a new frontier in the Americas  

SciTech Connect

In January of this year, Venezuela captured the attention of the international energy community by welcoming back the foreign oil companies that, 20 years earlier, it had shut out of the country by nationalizing the hydrocarbon sector. The tool used to attract that attention, a new exploration bidding round, is the most publicized event staged to date in the country`s aperture process. However, it is only the latest in a series of steps taken by officials to bring international oil and gas companies back to Caracas. Venezuela`s physical attraction is easily understood. The country possesses roughly one-half of Latin America`s (including Mexico) 125 billion bbl of established, conventional crude oil reserves, plus an estimated 300 billion bbl of additional, nonconventional reserves in the ultra-heavy crude belt of the Orinoco basin. Averaging 2.8 million bpd in 1996, Venezuelan crude production represents over 35% of regional oil output. Natural gas reserves total 138 Tcf, or just over one-half of the region`s total reserves of 274 Tcfg. Annual gas output averages just under 5 Tcf, of which roughly 30% is reinjected as part of tertiary oil recovery schemes. This paper reviews the incentives, deregulation, and government policies to restore the oil and gas industry to the country.

Reinsch, A.E. [Canadian Energy Research Inst., Calgary, Alberta (Canada)

1996-09-01

127

Geologic map of the Venezuela part of the Puerto Ayacucho 2 degrees x 3 degrees Quadrangle, Amazonas Federal Territory, Venezuela  

USGS Publications Warehouse

This map is one of a series of 1:500,000-scale maps that, along with several other products, stems from a cooperative agreement between the U.S. Geological Survey (USGS) and the Corporacion Venezolana de Guayana, Tecnica Minera, C.A. (TECMIN), a Venezuelan Government-owned mining and mineral exploration company. The agreement covered cooperative work carried out in the Precambrian Shield of southern Venezuela during 1987-1991 and included a geologic and mineral resource inventory, technology transfer, and scientific training (Wynn and others, in press). The Precambrian Guayana Shield (Escudo de Guyana, not to be confused with the neighboring country of Guyana) includes some of the oldest known rocks in the world (Mendoza, 1977) and also covers parts of neighboring Guyana, Surinam, French Guiana, Columbia, and Brazil. In Venezuela, it underlies most of Bolivar state and all of the Amazonas Federal Territory (see index map).

Wynn, Jeffrey C.; Olmore, Steven D.; Mendoza, Vicente; Garcia, Andres; Rendon, Ines; Estanga, Yasmin; Rincon, Haydee; Martinez, Felix; Lugo, Elis; Rivero, Nelson; Schruben, Paul G.

1994-01-01

128

Radioactive source materials in Los Estados Unidos de Venezuela  

USGS Publications Warehouse

This report summarizes the data available on radioactive source materials in Los Estados Unidos de Venezuela accumulated by geologists of the Direccions Tecnica de Geolgia and antecedent agencies prior to June 1951, and the writers from June to November 1951. The investigation comprised preliminary study, field examination, office studies, and the preparation of this report, in which the areas and localities examined are described in detail, the uranium potentialities of Venezuela are summarized, and recommendations are made. Preliminary study was made to select areas and rock types that were known or reported to be radioactive or that geologic experience suggests would be favorable host for uranium deposits, In the office, a study of gamma-ray well logs was started as one means of amassing general radiometric data and of rapidly scanning many of ye rocks in northern Venezuela; gamma-ray logs from about 140 representative wells were examined and their peaks of gamma intensity evaluated; in addition samples were analyzed radiometrically, and petrographically. Radiometic reconnaissance was made in the field during about 3 months of 1951, or about 12 areas, including over 100 localities in the State of Miranda, Carabobo, Yaracuy, Falcon, Lara, Trujillo, Zulia, Merida, Tachira, Bolivar, and Territory Delta Amacuro. During the course of the investigation, both in the filed and office, information was given about geology of uranium deposits, and in techniques used in prospecting and analysis. All studies and this report are designed to supplement and to strengthen the Direccion Tecnica de Geologias's program of investigation of radioactive source in Venezuela now in progress. The uranium potentialities of Los Estados de Venezuela are excellent for large, low-grade deposits of uraniferous phospahtic shales containing from 0.002 to 0.027 percent uranium; fair, for small or moderate-sized, low-grade placer deposits of thorium, rare-earth, and uranium minerals; poor, for high-grade hydrothermal pitchblende deposits; and highly possible for small, medium- to high-grade despots of carnotite-or copper-uranium bearing sandstone. Recommendations for the Venezuelan uranium program include 1) the systematic collection of a mass general radiometric data by examining sample collections, expanding the gamma-ray program, encouraging the use of Geiger counter by field geologists, and by enlisting the aid of the general public; 2) , the examination of specific areas or localities, chosen on the basis of geologic favorability from the results of the amassing of data, or obtained by hints and rumors; 3), the organization of a unit within the Direccion Tecnica de Geologica to direct, collection, and collate metric data. It is emphasized that to be most fruitful the program requires the application of sounds and imaginative geologic theory.

Wyant, Donald G.; Sharp, William N.; Rodriguez, Carlos Ponte

1953-01-01

129

Au-del de la Revolucin ! Un regard critique sur le Venezuela contemporain  

E-print Network

1 Au-delà de la ¡ Revolución ! Un regard critique sur le Venezuela contemporain Julien REBOTIER du Venezuela, affecte á différents degrés la géopolitique régionale, mais peine á consacrer les cambia la cara de Venezuela, modifica la geopolítica regional a diferentes grados, pero no logra que

Paris-Sud XI, Université de

130

Les risques sismiques Mrida (Venezuela). Pour une association des communauts la prvention de catastrophe dans les  

E-print Network

Les risques sismiques à Mérida (Venezuela). Pour une association des communautés à la prévention de louest) et de Trujillo (à lest) sont les trois états andins du Venezuela. Ils occupent le tracé de la cordillère andine du Venezuela qui se dégrade au nord-est dans létat de Lara en une transition montagneuse

Paris-Sud XI, Université de

131

Sesin 3 -Sistemas Distribuidos y Aplicaciones Mdicas 89 Escuela de Computacin Universidad Central de Venezuela UCV  

E-print Network

Central de Venezuela UCV #12;II Simposio Científico y Tecnológico en Computación 201290 Escuela de Computación Universidad Central de Venezuela UCV #12;Sesión 3 - Sistemas Distribuidos y Aplicaciones Médicas 91 Escuela de Computación Universidad Central de Venezuela UCV #12;II Simposio Científico y

Coto, Ernesto

132

Regional structure and tectonic history of the obliquely colliding Columbus foreland basin, offshore Trinidad and Venezuela  

Microsoft Academic Search

Cenozoic eastward migration of the Caribbean plate relative to the South American plate is recorded by an 1100-km-long Venezuela-Trinidad foreland basin which is oldest in western Venezuela (65–55Ma), of intermediate age in eastern Venezuela (34–20Ma) and youngest beneath the shelf and slope area of eastern offshore Trinidad (submarine Columbus basin, 15.0Ma-Recent). In this study of the regional structure, fault families,

Emilio Garciacaro; Paul Mann; Alejandro Escalona

2011-01-01

133

The hyper Americans! : Modern architecture in Venezuela during the 1950s.  

E-print Network

??During the 1950s, Venezuela embarked in an architectural venture marked by aesthetic, programmatic, and technological explorations. Politically framed by the international tension of the Cold… (more)

Villota Peña, Jorge

2014-01-01

134

A new approach to the oil business in Venezuela  

SciTech Connect

Petroleos de Venezuela S.A. (PDVSA) has been meeting during the past two years with a considerable number of companies (groups) with a view to possible associations for the reactivation of known fields, joint activities in barely explored areas and the exploitation, refining, upgrading and marketing of crudes from the Orinoco Belt holder of immense reserves of extra-heavy crudes and bitumens. In Venezuela, a new approach to the oil business is under way. On January 1976, the law nationalizing the Venezuelan oil industry became effective establishing that the government retains the sole rights to the country's petroleum industry. However, Article 5 of the law made provision for associations in cases considered to be of [open quotes]National Interest.[close quotes] PDVSA became the wholly government-owned holding entity, encompassing 26 subsidiaries and affiliates. Other energy segments, particularly coal and petrochemicals, were not included in the law and since 1984 several associations with non-governmental entities have been established in Venezuela and very valuable experience has been garnered. Similarly, partnerships and acquisitions have been made in Europe and USA, mostly in refining, through PDVSA. The international petroleum industry foresees a modest, but steady increase in production during the coming decade, particularly in the second half of the nineties. This effect, added to the globalization concept, is making the traditional vertically integrated oil companies look for diverse [open quotes]lateral[close quotes] associations between groups, private and/or state owned with common interests, that will give greater security to sources of supply and market share.

Pradas, F.; Valdes, G. (Petroleos de Venezuela, Caracas (Venezuela))

1993-02-01

135

Present Status of Historical Seismicity Studies in Colombia and Venezuela  

NASA Astrophysics Data System (ADS)

After the publication of the SISRA (CERESIS-1985) regional project, a unified catalog of seismic parameters and intensities for South America, researchers in historical seismicity have continued advancing on different scales in the area of this study of seismic hazard. The most important initiatives carried out in this area in Colombia and Venezuela can be grouped as follows: a) Reviews of destructive earthquakes in national and international historic archives, principally by Altez and FUNVISIS in Venezuela and Espinosa, Salcedo, and Sarabia et al in Colombia, leading to the preparation of seismologic catalogues, scientific and dissemination articles, reports, books, among others. b) Organization and systematization of historic information to develop public domain data bases and information, specifically the Historic Seismologic Teleinformation System in Venezuela, carried out between 2004 and 2008 under the coordination of Christl Palme and accessible on-line: http://sismicidad.ciens.ula.ve. As well, the "Historia Sísmica de Colombia 1550-1830" (Seismic History in Colombia 1550-1830) data base, in CD-ROM, by Espinosa Baquero (2003) and the historic seismicity information system of Colombia (Servicio Geológico Colombiano-Universidad Nacional de Colombia), published on the internet in 2012: http://agata.ingeominas.gov.co:9090/SismicidadHistorica/. c) Macroseismic studies for the development of intensity attenuation equations and the quantification and revaluation of basic historic earthquake parameters using isoseismal maps (Rengifo et al., Palme et al., Salcedo et al., among others) and procedures such as Boxer and Bakun & Wentworth (Palme et al., Dimaté, among others), which have produced significant changes in the parameters of some of the large earthquakes. d) Symposiums of researchers to promote interest and development in the discipline, including Jornadas Venezolanas de Sismología Histórica (Venezuelan Congress of Historical Seismology), held periodically between 1997 and 2012, the year of the sixth edition. As well, national and international research groups have been formed to work actively on global projects, such as the Geophysics Laboratory of Universidad de Los Andes in Venezuela. In the future, international groups will be formed to jointly treat issues including localization and size of destructive events along borders, common scales for the evaluation of intensities, integrated data bases, etc. Additionally the methods employed will be validated by paleoseismology, neotectonics and instrumental seismicity, among others.

Sarabia, A.; Cifuentes, H.; Altez Ortega, R.; Palme, C.; Dimate, C.

2013-05-01

136

Venezuela No. 1 oil import source in S. America  

SciTech Connect

This paper reports that with the exception of Venezuela, the U.S. is likely to import much oil from South American countries through 2010, the General Accounting Office reports. GAO, a congressional watchdog agency, noted the U.S. imports about 4% of its oil from Colombia, Ecuador, and Trinidad and Tobago and possibly could import from Argentina, Bolivia, Brazil, Chile, and Peru in the future. It the the eight countries' crude oil reserves are expected to increase about 30% by 2000, then slide about 2% by 2010. Their oil production is expected to climb about 21% over 1990 by 2000, then level off until 2010.

Not Available

1992-08-10

137

Clay mineralogy of surface sediments as a tool for deciphering river contributions to the Cariaco Basin (Venezuela)  

E-print Network

Basin (Venezuela) V. Bout-Roumazeilles,1 A. Riboulleau,1 E. Armynot du Châtelet,1 L. Lorenzoni,3 N for deciphering river contributions to the Cariaco Basin (Venezuela), J. Geophys. Res. Oceans, 118, doi:10

Meyers, Steven D.

138

Using the Five Themes of Geography To Teach about Venezuela and Mexico.  

ERIC Educational Resources Information Center

Activities that employ the five themes of geography--location, place, relationships within places, movement, and regions--to teach about Venezuela and Mexico are described in this document. Each theme has objectives, a list of materials, and three types of activities--exploration, invention, and expansion. Background information on Venezuela and…

Sunal, Cynthia Szymanski; Christensen, Lois

139

Molecular and Antigenic Comparison of Ehrlichia canis Isolates from Dogs, Ticks, and a Human in Venezuela  

Microsoft Academic Search

We previously culture isolated a strain of Ehrlichia canis, the causative agent of canine ehrlichiosis, from a human in Venezuela. In the present study, we examined whether dogs and ticks are infected with E. canis in Venezuela and, if so, whether this is the same strain as the human isolate. PCR analysis using E. canis-specific primers revealed that 17 of

AHMET UNVER; MIRIAM PEREZ; NELSON ORELLANA; HAIBIN HUANG; YASUKO RIKIHISA; Departmento de Medicina Cirugia

2001-01-01

140

Earnings and Education in Venezuela: An Update from the 1987 Household Survey.  

ERIC Educational Resources Information Center

Uses data from Venezuela's 1987 Household Survey to update returns to education and compare them to 1975 and 1984 figures. Returns to education have been maintained despite the educational explosion occurring in Venezuela during the period investigated. Although higher education is most heavily subsidized, primary education remains the most…

Psacharopoulos, George; Alam, Asad

1991-01-01

141

Wages and foreign ownership A comparative study of Mexico, Venezuela, and the United States  

Microsoft Academic Search

This paper explores the relationship between wages and foreign investment in Mexico, Venezuela, and the United States. Despite very different economic conditions and levels of development, we find one fact that is robust across all three countries: higher levels of foreign investment are associated with higher wages. However, in Mexico and Venezuela, foreign investment is associated with higher wages only

Brian Aitken; Ann Harrison; Robert E. Lipsey

1996-01-01

142

Ecology of an isolated mangrove lagoon (Playa Medina, Venezuela) and its potential  

E-print Network

Ecology of an isolated mangrove lagoon (Playa Medina, Venezuela) and its potential use as sewage conditions of a coastal mangrove lagoon in Venezuela which is completely isolated from the sea, lacking any is to relate some of the effects of disconnection, with the potential use of the mangrove as a sewage pond

Vegas Vlarrúbia, Teresa

143

Socio-Economic Aspects of National Communication Systems: III. Radio Broadcasting in Venezuela. Communication and Society, 12.  

ERIC Educational Resources Information Center

The third in a series that examines the role of radio broadcasting in the process of socioeconomic and cultural change in three countries with different types of broadcasting organization--Austria, Czechoslovakia, and Venezuela--this volume focuses on Venezuela. An overview of radio broadcasting in Venezuela describes various aspects and provides…

Capriles, Oswaldo; And Others

144

Comparison of species-specific oxygen isotope paleotemperature equations: Sensitivity analysis using planktonic foraminifera from the Cariaco Basin, Venezuela  

E-print Network

using planktonic foraminifera from the Cariaco Basin, Venezuela Katherine E. Wejnert a, , Robert C, Venezuela a b s t r a c ta r t i c l e i n f o Article history: Received 6 December 2011 Received in revised biweekly sediment trap samples collected in Cariaco Basin, Venezuela between 2003 and 2008. Sixteen

Meyers, Steven D.

145

EL IMPACTO DEL CONFLICTO POLTICO SOBRE LAS ORGANIZACIONES DE LA SOCIEDAD CIVIL EN VENEZUELA: EL DILEMA ENTRE PARTICIPACIN Y REPRESENTACIN.  

E-print Network

EL IMPACTO DEL CONFLICTO POLÍTICO SOBRE LAS ORGANIZACIONES DE LA SOCIEDAD CIVIL EN VENEZUELA: EL Universidad Central de Venezuela gomezcal@cantv.net RESUMEN: En los años recientes, la pérdida de legitimidad, conflicto político, Venezuela #12;INTRODUCCI�N En este trabajo intentamos analizar algunos de los impactos

Paris-Sud XI, Université de

146

Expression of the chaplin and rodlin hydrophobic sheath proteins in Streptomyces venezuelae is controlled by sBldN  

E-print Network

Expression of the chaplin and rodlin hydrophobic sheath proteins in Streptomyces venezuelae) genes by exploiting a new model species, Streptomyces venezuelae, which sporulates in liquid culture discussed in this report, Streptomy- ces venezuelae has two long chaplins (ChpB and ChpC) and four short

Buttner, Mark

147

Raptor abundance and distribution in the Llanos wetlands of Venezuela  

USGS Publications Warehouse

The Llanos of Venezuela is a 275 000-km2 freshwater wetland long recognized as an important habitat for waterbirds. However, little information exists on the raptor community of the region. We conducted raptor surveys in the Southwestern and Western Llanos during 2000-02 and detected 28 species representing 19 genera. Overall, areas of the Llanos that we sampled contained 52% of all raptor species and more than 70% of the kites, buteos, and subbuteos known to inhabit Venezuela. Regional differences in the mean number per route for four of the 14 most common species, the Crested Caracara (Caracara plancus), Black-collared Hawk (Busarellus nigricollis), American Kestrel (Falco sparverius), and Osprey (Pandion haliaetus), were significant (P < 0.0018) in relation to the wet or dry seasons. Of the 14 less common species, six were detected in only one season (wet or dry). The Southwestern and Western regions of the Llanos support a rich raptor community composed primarily of nonmigratory wetland-dependent and upland-terrestrial species. ?? 2005 The Raptor Research Foundation, Inc.

Jensen, W.J.; Gregory, M.S.; Baldassarre, G.A.; Vilella, F.J.; Bildstein, K.L.

2005-01-01

148

Venezuela, Trinidad and Tobago: crude oil potential from known deposits  

SciTech Connect

This report presents an analysis of the future oil supply potential from the known fields of the republics of Venezuela and Trinidad and Tobago. Presented herein are estimates of (1) original oil in place; (2) ultimate recovery; (3) remaining reserves; and (4) projected supply patterns. A discussion of the methodology for projecting supply patterns is also presented. This analysis does not include recoverable resources from nonconventional deposits such as tar sands and oil shale. The Republic of Venezuela ranked 7th in 1979 in production among the oil producers of the world and is one of the leading exporters of crude oil. During 1979, production averaged about 2.3 million (MM) barrels of oil per day (bopd). It exported an average of 1.2 MM bopd of crude oil in 1978 and 690 thousand (M) bopd of refined products during the first eleven months of 1978. Thus, it exported all but 12 to 13 percent of the petroleum produced in 1978; the rest is consumed domestically. About 1/3 of the country's exports are received by the United States, and it was the 5th and 3rd largest supplier of crude oil and refined products to the United States in 1978 and 1979, respectively.

Dietzman, W.D.; Rafidi, N.R.; Warner, A.J.

1981-07-01

149

Intestinal helminths of capybaras, Hydrochoerus hydrochaeris, from Venezuela.  

PubMed

Quantitative parameters of intestinal helminth species and their potential relations to host characteristics in a population of capybaras (Hydrochoerus hydrochaeris) from Venezuela are reported for the first time. The intestines of 40 capybaras were collected during the 1992-annual harvest at Hato El Cedral. Six helminth species were found: 2 cestodes (Monoecocestus macrobursatum, M. hagmanni), 2 nematodes (Viannella hydrochoeri, Protozoophaga obesa), and 2 trematodes (Hippocrepis hippocrepis, Taxorchis schistocotyle). This is the first report for M. macrobursatum in Venezuela. Helminth abundance did not differ between sexes or age classes. Although patterns of distribution for all helminth species were overdispersed, the high prevalence found for all species (over 70%) and the high abundance observed for nematodes made it difficult to assess the effect that these helminths may produce on capybaras. Nevertheless, the negative associations found between the body condition of capybaras and helminth intensity for M. macrobursatum and V. hydrochoeri, might be pointing out potential host population regulatory role for these parasites which require further research. PMID:15558163

Salas, Viviana; Herrera, Emilio A

2004-10-01

150

Paralytic shellfish poisoning (PSP) in Margarita Island, Venezuela.  

PubMed

A severe outbreak of Paralytic Shellfish Poisoning (PSP) occurred in Manzanillo and Guayacán, northwestern coast of Margarita Island, Venezuela, between August and October 1991. A bloom of dinoflagellates including Prorocentrum gracile, Gymnodinium catenatum and Alexandrium tamarense seemed to be responsible for this outbreak. Levels of PSP toxins in mussels (Perna perna) exceeded the international safety limit of saxitoxin, 80 microg STX/100 microg meat. PSP toxin values varied between 2548 and 115 microg STX/100 g meat in Manzanillo, and between 1422 and 86 microg STX/100 g meat in Guayacán. At both locations, the highest levels were detected in August, when 24 patients exhibited typical symptoms of PSP toxicity after consuming cooked mussels (16 required hospitalization). A high pressure liquid chromatographic (HPLC) procedure was recently used on the 1991 samples. The major toxin detected in samples of both locations was decarbamoyl saxitoxin (dcSTX), but low concentrations of saxitoxin were also found in Manzanillo samples. Gonyautoxins GTX1, GTX2 and GTX3 were detected only at Guayacán, while in both locations, decarbamoylgonyatouxin (dcGTX2,3) toxins were detected. These findings represent the first time that causative toxins of PSP in Venezuela have been chemically identified, and confirm the presence of dcSTX and dcGTX in mussels from the Caribbean Sea. The presence of dcSTX and dcGTX in shellfish is indicative that Gymnodinium catenatum was a causative organism for outbreak of PSP. PMID:17465121

La Barbera-Sánchez, Amelia; Franco Soler, Jose; Rojas de Astudillo, Luisa; Chang-Yen, Ivan

2004-09-01

151

SI GANAMOS NOSOTRAS, GANA TODO EL MUNDO. IMPORTANCIA DE LAS ASOCIACIONES DE MUJERES EN LA LUCHA CONTRA LA EXCLUSIÓN SOCIAL  

Microsoft Academic Search

RESUMEN Es la intención de esta comunicación reflexionar y visualizar la importancia individual, grupal y comunitaria que tienen las organizaciones de mujeres en la lucha contra la exclusión social y en el fortalecimiento del Estado de bienestar. Su mera existencia cuestiona profundamente la lógica que articula esta sociedad patriarcal, porque expresa la presencia y reivindicaciones de sectores y colectivos sociales

ANTONIA CORONA AGUILAR

152

Potential for Great Thrust Earthquakes in NE Colombia & NW Venezuela  

NASA Astrophysics Data System (ADS)

Sixty-five percent of the ?19 mm/yr eastward velocity of the Caribbean Plate north of Aruba and the Guajira peninsula relative to the South American plate is accommodated by dextral slip on the Bocono Fault system in NW Venezuela at 12±1 mm/yr, the remaining ~3 mm/yr of shear apparently distributed to the NW of the fault (Perez et al., 2011). The N40E strike of the Bocono fault system, however, requires that 10.6±1 mm/yr of convergence should accompany this partitioned dextral shear, but GPS measurements reveal that less than 25% of this convergence occurs across the Venezuelan Andes. The remaining 6-8 mm of convergence is presumably accommodated by incipient subduction between the Bocono fault and a trench 300 km NW of the northern coast of Colombia. Hence NW Venezuela and NE Colombia may occasionally host great earthquakes. Our current poor understanding of the geometry of the plate interface permits the plate to be locked 300 km down-dip and possibly 600 km along-strike, and if the plate slips in 10 m ruptures it could do so every 1200 years in a M~9 earthquake. No great earthquake has occurred since 1492, since when ~4 m of potential slip has developed, but should slip occur on just 10% of the hypothesized décollement (100x150 km) it could do so now in an Mw=8.2 earthquake. In that a potential Mw>8 earthquake poses a future seismic and tsunami threat to the Caribbean it is important to examine whether great earthquakes have occurred previously near the NW Venezuela coast. It is possible that creep accommodates the entire convergence signal, since there is no suggestion from microseismicity for an abrupt locked-to-sliding transition, as, for example, signifies its location in the Himalaya. An alternative measure of future potential seismic energy release is to identify the locus and rate of present-day strain contraction. To this end, Venezuelan, Colombian and US (CU and UNAVCO) investigators are installing an array of more than a dozen continuous operating GPS sites in the region. Studies of tsunami deposits on the Dutch Antilles suggest that the provenance of paleotsunami responsible for moving 10-100 ton blocks of coral onshore in the past two millennia has been from the east (Sheffers, 2002), and not from the north or south as we might expect from a NW Venezuelan earthquake. The existence of precariously balanced rocks in the region provides an alternative constraint on the occurrence of large local accelerations. The survival of at least four precariously balanced megablocks on the island of Aruba suggests that horizontal accelerations here have not exceeded 1 g for the past several millennia, but refined numerical estimates of potential shaking intensity consistent with their survival have yet to be completed. Accelerations exceeded 2.5 g in the Tohuko 2011 earthquake but above the Mexican subduction zone, accelerations have typically not exceeded 0.5 g in recent Mw~7.5 earthquakes, and hence the existence of these blocks may not exclude the historical occurrence of damaging earthquakes. A broader search for surviving strong-motion indicators in Colombia and Venezuela is planned during the installation of the GPS array.

Bilham, R. G.; Mencin, D.

2013-05-01

153

Swarms in Venezuela: characterization of the involved seismicity  

NASA Astrophysics Data System (ADS)

A swarm is a gradual increase and decay of seismicity in time forming a cluster of seismic events without the occurrence of a particular mainshock or major earthquake. In Venezuela, there are few sequences of the swarm type in the instrumental age of seismology. These swarms are not related to volcanic activity and there is few studied evidence to lead the understanding of the triggering mechanism of the venezuelan swarm activity. We compile instrumental information in order to reassess and compare five swarms occurred in 1989, 1991, 1995, 2006 and 2011. Four of these swarms are located in areas where predominant quaternary faults generate most of the background seismicity. We investigated the statistical properties of these swarms and activity patterns under the frequency size distribution and the interevent-time distribution to study the time between two consecutive events as a stationary point process.

Vasquez, R.; Granado, C.; Borges, N.

2013-05-01

154

Venezuela's stake in US refining may grow: xenophobia addressed  

SciTech Connect

Is this an invasion of U.S. oil industry sovereignty, or a happy marriage of upstream and downstream between US and foreign interests. Venezuela, a founding member of the Organization of Petroleum Exporting Countries who has also been a chief supplier to the US during times of peace and war, now owns half of two important US refining and marketing organizations. Many US marketers have felt uneasy about this foreign penetration of their turf. In this issue, for the sake of public information, the entire policy statement from the leader of that Venezuelan market strategy is provided. This issue also contains the following: (1) ED refining netback data for the US Gulf and West Coasts, Rotterdam, and Singapore as of late September, 1987; and (2) ED fuel price/tax series for countries of the Eastern Hemisphere, Sept. 19 edition. 4 figures, 6 tables.

Not Available

1987-09-23

155

Simuliidae and their relation to human onchocerciasis in northern Venezuela  

PubMed Central

A study of the vectors of onchocerciasis was carried out in 1961 in northern Venezuela at the request of the Venezuelan Government. This article, based on the report submitted, records various observations made—mainly during the dry season—on the identification and biology of the Simuliidae and on the possibilities of controlling them. Twelve Simulium forms were encountered; special attention was paid to the two common man-biting species; S. exiguum, which was abundant but of uncertain relation to onchocerciasis, and S. metallicum. The authors conclude that S. metallicum is the main or only vector in the area studied, but that S. exiguum might possibly also transmit onchocerciasis in certain places near large streams where it is found in great numbers. PMID:20604129

Lewis, D. J.; de Aldecoa, R. Ibáñez

1962-01-01

156

Seismic anisotropy and mantle flow beneath western Venezuela  

NASA Astrophysics Data System (ADS)

We measured shear wave splitting from SKS and SKKS data recorded by the national seismic network of Venezuela and a linear broadband PASSCAL/Rice seismic array across the Merida Andes. The linear array was installed as a second phase of the passive seismic component of the BOLIVAR project (Broadband Onshore-offshore Lithospheric Investigation of Venezuela and the Antilles arc Region) to better understand the complicated regional tectonics in western Venezuela. Polarization direction (?) of the faster S wave and delay time (?t) between the fast and slow wavelets from 20 stations were obtained using a stacking method proposed by Wolfe and Silver (1998). For each station, SKS or SKKS waveform data from 2 to 36 earthquakes, mostly from the Tonga subduction zone, were selected for splitting analysis. We assumed that shear wave splitting observed at each station is caused by upper mantle seismic anisotropy beneath the station. The best splitting parameters (?,?t) were estimated when the summed eigenvalue ratio ?(SNRi[?2i(?,?t)/?1i(?,?t)]) of the covariance matrix of the corrected particle motion reaches its minimum. We used signal-to-noise ratio (SNR) calculated from a noise time window before SKS as the weight of the summation. The fast polarization directions can be divided into 3 zones, all in agreement with local GPS data: The first zone is the stations north of the dextral strike-slip Oca fault, an extinct part of the San Sebastian-El Pilar plate boundary zone. These stations show the largest split times (1.6-2.0s), oriented in a roughly EW direction, and are similar to splitting observations made further to the east along the strike slip plate boundary. Zone two is the Maracaibo block, bounded on the southeast by the right lateral Bocono fault, where split orientations are at N45°E, suggesting that the observed seismic anisotropy is likely caused by lithospheric deformation parallel to the Bocono. Zone three is east of the Bocono fault inside the Barinas-Apure Basin, where the measured split times are smaller (0.6-1.0s) with an EW fast direction that is consistent with those observed at the Guarico Basin, Maturin Basin and the Guayana shield in the east (Growdon et al., 2009), and are interpreted as orientation with the motion of the continent. Russo and Silver (1994) proposed that the rollback of the Nazca plate induced a trench-parallel NS flow that passes around the northwest corner of the subducting plate and along the northern edge of South America, forming an eastward flow beneath the southern Caribbean plate. The observed seismic anisotropy in western Venezuela can be roughly explained by a combination of this corner flow, the westward drift of the South America continent due to the opening of Atlantic Ocean, modulated by the northward escape of the Maracaibo block.

Masy, J.; Niu, F.; Levander, A.

2009-12-01

157

Venezuela 2000 restructures its electric power sector to ensure competitiveness  

SciTech Connect

Today, it is well known that the countries that are best equipped to develop their production are not those with the most natural resources but those who have the best trained people, most technical resources and that base their development on competitiveness. The State model is, definitely, not one that offers the greatest advantages, and Venezuela is an example of this. Even when, thanks to the economic boom the country enjoyed in the 70s and 80s, it was able to cost the investments required to develop its infrastructure and to prepare a first class human contingent, over the long term, competition was discouraged and waste encouraged. The result was that, even when Venezuela had vast economic resources compared to its relatively small population, it was not able to become the exception to the rule and succeed in applying this model--now considered obsolete in many countries--indefinitely. Another model based on private ownership has begun to take its place, one that has made it possible to cost the increasingly large investments required, involves opening up these sectors to private capital, and uses the phenomenon of globalization--a major driving force behind competition and one that has wrought considerable change in all corners of the increasingly smaller planet. This paper describes the steps that different sectors in the country have been taking to implement this new model in the electric power sector, such as developing draft legislation for regulating the Sector, very shortly to culminate in the passing of an electric power law by Congress; opening up the Sector to private investors (privatization); dividing the electric power industry into four business units (generation, transmission, distribution and marketing); the electric power market; and other innovations currently being implemented.

Alvarez, C.E. [Electrical Power Sector, Caracas (Venezuela)

1999-11-01

158

Multidata remote sensing approach to regional geologic mapping in Venezuela  

SciTech Connect

Remote Sensing played an important role in evaluating the exploration potential of selected lease blocks in Venezuela. Data sets used ranged from regional Landsat and airborne radar (SLAR) surveys to high-quality cloud-free air photos for local but largely inaccessible terrains. The resulting data base provided a framework for the conventional analyses of surface and subsurface information available to the project team. (1) Regional surface geology and major structural elements were interpreted from Landsat MSS imagery supplemented by TM and a regional 1:250,000 airborne radar (SLAR) survey. Evidence of dextral offset, en echelon folds and major thoroughgoing faults suggest a regional transpressional system modified by local extension and readjustment between small-scale crustal blocks. Surface expression of the major structural elements diminishes to the east, but can often be extended beneath the coastal plain by drainage anomalies and subtle geomorphic trends. (2) Environmental conditions were mapped using the high resolution airborne radar images which were used to relate vegetation types to surface texture and elevation; wetlands, outcrop and cultural features to image brightness. Additional work using multispectral TM or SPOT imagery is planned to more accurately define environmental conditions and provide a baseline for monitoring future trends. (3) Offshore oil seeps were detected using ERS-1 satellite radar (SAR) and known seeps in the Gulf of Paria as analogs. While partially successful, natural surfactants, wind shadow and a surprising variety of other phenomena created {open_quotes}false alarms{close_quotes} which required other supporting data and field sampling to verify the results. Key elements of the remote sensing analyses will be incorporated into a comprehensive geographic information (GIS) which will eventually include all of Venezuela.

Baker, R.N. [E& P Technology Group, Amoco Corp., Houston, TX (United States)

1996-08-01

159

A reservoir characterization for a complex multilayered system in Eastern Venezuela  

E-print Network

A RESERVOIR CHARACTERIZATION FOR A COMPI. EX MULTILAYERED SYSTEM IN EASTERN VENEZUELA A Thesis by CARMEN ESTHER AVILA Submitted to the Once of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree...

Avila, Carmen Esther

1998-01-01

160

A revision of the Larainae (Coleoptera, Elmidae) of Venezuela, with description of nine new species  

E-print Network

The species of the riffle beetle subfamily Larainae occurring in Venezuela are revised. Examination of 756 specimens yielded 22 species in nine genera occurring throughout the country. Seven species are newly recorded from the country: Phanoceroides...

Maier, Crystal A.

2013-09-05

161

A Descriptive Chronology of Films by Women in Venezuela, 1952-92.  

ERIC Educational Resources Information Center

Offers an annotated chronology of Venezuelan films, representing a first step toward a general history of women's filmmaking in Venezuela. Suggests that the participation of women directors closely follows the curve of national film production in general. (RS)

Schwartzman, Karen

1993-01-01

162

Biological and phylogenetic characterization of a genotype VII Newcastle disease virus from Venezuela: Efficacy of vaccination  

Technology Transfer Automated Retrieval System (TEKTRAN)

Here we describe the characterization a virulent genotype VII Newcastle disease virus (NDV) from Venezuela and evaluate the efficacy of heterologous genotype commercial vaccination under field and controlled rearing conditions. Biological pathotyping and molecular analysis were applied. Results sh...

163

Decentralization and Regionalization in the Ministry of Education: The Case of Venezuela  

ERIC Educational Resources Information Center

This research is an effort to analyze the process of organizational change as it takes place within one segment of the public administration mechanism in Venezuela--The Ministry of Education. (Editor/RK)

Hanson, Mark

1976-01-01

164

Correlation of the Jurassic through Oligocene Stratigraphic Units of Trinidad and Northeastern Venezuela  

SciTech Connect

The Jurassic through Oligocene stratigraphies of Trinidad and the Serrenia del Interior of eastern Venezuela exhibit many similarities because of their proximity on the passive continental margins of northeastern South America. A slightly later subsidence in eastern Venezuela, and the generally deeper-water sedimentation in Trinidad, is interpreted to be the result of a serration of the original rift margin, producing an eastern Venezuela promontory and Trinidadian re-entrant. We interpret these serrations to be the result of oblique (NW-SE) spreading of North and South America during Middle and late Jurassic time. The stratigraphies of northeastern Venezuela and Trinidad contrast in the Hauterivan-Albian interval, with dynamic shallow shelf environments prevailing in the Serrenia del Interior and deeper marine submarine-fan deposition in Trinidad. Both areas develop middle to Upper Cretaceous source rocks during a time of eustatic sea level high and widespread oceanic anoxia. 15 refs., 4 fig.

Algar, S. [Enterprise Oil, London (United Kingdom); Erikson, J.P. [Univ. of California, Davis, CA (United States)

1995-04-01

165

Phytomass structure of natural plant communities on spodosols in southern Venezuela: the Bana woodland  

Microsoft Academic Search

Bana, or Low Amazon Caatinga is an evergreen sclerophyllous woodland. It occurs on bleached quartz sands in the lowlands of SW Venezuela, where it occupies relatively small ‘islands’ amidst Tall Amazon Caatinga which is exclusively developed on tropaquods.

F. Bongers; D. Engelen; H. Klinge

1985-01-01

166

EVALUACIÓN COMPARATIVA DE HÍBRIDOS DE GIRASOL (Helianthus annus L.) EN DOS ZONAS PRODUCTORAS DE VENEZUELA  

Microsoft Academic Search

Sunflower (Helianthus annus L.) hybrids evaluation in two producing areas of Venezuela In the commercial sunflower sowing of Venezuela imported hybrid seeds are used, so the genetic materials have to be previously evaluated to know their performance in the growing zones. The purpose of this paper was to evaluate the hybrids MG2, MG4, EM787032, EM777364, EM776541, TRISOL 600, M742, and

Jesús Ávila; Antonio Díaz; Ramiro De La Cruz; Novis Moreno; Dimas Romero; Ramón Cáceres; Luis Gutiérrez; Régulo Flores

2007-01-01

167

Four new species of Andean Pilea (Urticaceae), with additional notes on the genus in Venezuela  

PubMed Central

Abstract Four new species of Pilea (Urticaceae) from the Andes of Venezuela are described and illustrated: Pilea matthewii sp. nov., Pilea miguelii sp. nov., Pilea nicholasii sp. nov., and Pilea nidiae sp. nov. The affinities of these species and their positions within the informal classifications of Pilea proposed by Weddell and Killip are discussed. Notes on other species of Pilea found in Venezuela also are presented. PMID:25383012

Dorr, Laurence J.; Stergios, Basil

2014-01-01

168

Structural Model of the Tucupita Field, Eastern Venezuela Basin  

NASA Astrophysics Data System (ADS)

The Tucupita Field has an area of 73,51 Km2, is located between the states of Monagas and Delta Amacuro, geologically is located at the greater Temblador area in the Eastern Venezuela Basin, where the Oficina Formation's sands represent the main hydrocarbons reservoirs. From the results of the seismic reprocessing realized by Fusion Petroleum Technologies, Inc., the structural model of this field was done as initial step to the geocellular model of the Oficina-40 Reservoir, which was defined as a Faulted Relay Ramp, where the normal faults are dominant with NE-SW orientation Introduction The Tucupita Field is a mature oilfield at the greater Temblador area, however most of the wells were completed in the upper sands, therefore the main study is focused in the geological characterization of the Oficina-40 Reservoir's lower sands, starting by the structural model Previous Studies 1. Proyecto Tucupita 3D The seismic data of the Tucupita Field were adquired in 1996 by Western Atlas of Venezuela for the Benton Vinccler Company. The UTM coordinates of the wells used in this project, have been taken to make this geological model 2. Soporte Geofísico Integrado The seismic project Tucupita was processed by Fusion Petroleum Technologies Inc., in Houston and consisted of reprocessing and pre-stack migration in time (PSTM) and pre-stack migration in depth (PSDM), this data belong to the Petrodelta Company Based on the regional stratigraphy, were validated the "picks" to make the structural sections to support research with hard data. After, it proceeded to interpret the structural style of the field from the seismic amplitude cube. Then, it was done the faults modelling and the stratigraphic horizons to carry out the geocellular model Three structural sections were realized, which was interpreted like a faulted monocline, whose peak is located southward, where justly the wells are located. The contact oil-water was interpreted to -5648'. Echelon faults were interpreted in a structure of the Faulted Relay Ramp (Figure 1), defined by two normal faults with orientation NE-SW, including the main fault of Tucupita Field Conclusions 1. The development of this structural model led to geological characterization of the Oficina-40 Reservoir, integrating this interpretation in a geocellular model to calculate the STOIIP.The Tucupita Field is characterized structurally as a Faulted Relay Ramp References 1. Fusion Petroleum Technologies, Inc. 2009. PROYECTO TUCUPITA SOPORTE GEOFÍSICO INTEGRADO; Figure 1. Faulted Relay Ramp, Tucupita Field

Arteaga, L. A.

2013-05-01

169

El deportista y el pH: importancia del lactato y la dieta  

Microsoft Academic Search

No existe evidencia bioquímica clara para sostener que la producción de lactato cause acidosis, sino más bien todo lo contrario, ya que el lactato retrasa y no causa la aparición de dicha acidosis. Además de la manipulación previa a un evento deportivo de las condiciones ácido-básicas del medio interno, mediante el empleo de ayudas ergogénicas como pudiera ser el bicarbonato

Joaquín Pérez-Guisado

2009-01-01

170

CARACTERÍSTICAS E IMPORTANCIA QUE PRESENTA LA AUTONOMÍA PARA UN ALUMNO EN EAD  

Microsoft Academic Search

Desde entonces he dedicado una gran parte de mi vida a la Enseñanza, tratando de lograr en los alumnos un aprendizaje significativo con el fin de que se motivaran y continuaran estudiando hasta lograr un aprendizaje autónomo que los posibilitara a actuar de una manera reflexiva y crítica, tanto en el ámbito educativo como en su vida cotidiana. Esta forma

Sheina Leoni

2009-01-01

171

LA BIOÉTICA COMO QUEHACER FILOSÓFICO  

PubMed Central

El artículo examina el estatuto epistemológico de la bioética como disciplina académica. El autor sostiene que el estatuto epistemológico de un discurso lo determina la pregunta fundamental que se plantea y la respuesta que se busca, focos integradores del discurso. En el caso de la bioética, la pregunta fundamental es de índole moral. La bioética es pues una disciplina ética que tiene su hogar epistemológico en la filosofía. El autor también defiende el concepto de “éticas aplicadas”. Sugiere finalmente que el método de la bioética, sobre todo la que se hace desde nuestras latitudes, debería adoptar el círculo hermenéutico como metodología para su filosofar. PMID:20463860

Ferrer, Jorge José

2009-01-01

172

Late quaternary environmental history of Lake Valencia, Venezuela  

USGS Publications Warehouse

Chemical, paleontological, and mineralogical analyses of a 7.5-meter core from the middle of Lake Valencia, Venezuela, have provided information on the paleoclimatic history of this low-elevation, low-latitude site for the last 13,000 years. The data show that dry climates existed in this region from 13,000 years before present (B.P.) until about 10,000 years B.P. The Lake Valencia Basin was occupied by intermittent saline marshes at that time. About 10,000 years B.P., a permanent lake of fluctuating salinity formed and arboreal plant communities replaced the earlier dominant xeric herbaceous vegetation and marsh plants. By 8500 years B.P., Lake Valencia reached moderate to low salinities and discharged water; the modern vegetation became established at that time. After 8500 years B.P., the lake twice ceased discharging as a result of reduced watershed moisture. The second of these drying episodes is still in progress and has been aggravated by human activities in the watershed. Copyright ?? 1981 AAAS.

Platt, Bradbury J.; Leyden, B.; Salgado-Labouriau, M.; Lewis, W.M., Jr.; Schubert, C.; Binford, M.W.; Frey, D.G.; Whitehead, D.R.; Weibezahn, F.H.

1981-01-01

173

Sedimentary sequence evolution in a Foredeep basin: Eastern Venezuela  

SciTech Connect

Well log-seismic sequence stratigraphy analysis in the Eastern Venezuela Foreland Basin leads to study of the evolution of sedimentary sequences onto the Cretaceous-Paleocene passive margin. This basin comprises two different foredeep sub-basins: The Guarico subbasin to the west, older, and the Maturin sub-basin to the east, younger. A foredeep switching between these two sub-basins is observed at 12.5 m.y. Seismic interpretation and well log sections across the study area show sedimentary sequences with transgressive sands and coastal onlaps to the east-southeast for the Guarico sub-basin, as well as truncations below the switching sequence (12.5 m.y.), and the Maturin sub-basin shows apparent coastal onlaps to the west-northwest, as well as a marine onlap (deeper water) in the west, where it starts to establish. Sequence stratigraphy analysis of these sequences with well logs allowed the study of the evolution of stratigraphic section from Paleocene to middle Miocene (68.0-12.0 m.y.). On the basis of well log patterns, the sequences were divided in regressive-transgressive-regressive sedimentary cycles caused by changes in relative sea level. Facies distributions were analyzed and the sequences were divided into simple sequences or sub- sequences of a greater frequencies than third order depositional sequences.

Bejarano, C.; Funes, D. [Corpoven S.A., Puerto La Cruz (Venezuela); Sarzalho, S.; Audemard, F.; Flores, G. [Caracas (Venezuela)

1996-08-01

174

Cretaceous to Eocene passive margin sedimentation in Northeastern Venezuela  

SciTech Connect

Twenty two palinspastic paleogeographic maps are presented for the Cretaceous to Eocene strata of the Serrania del Interior of northeastern Venezuela. The mapped lithologies, environmental conditions, and evolving depositional systems record [approximately]90 m.y. of dominantly marine sedimentation on the only observable Mesozoic passive margin in the Western Hemisphere. The depositional systems of the passive margin are heterogeneous at lateral (i.e., along-margin) length scales greater than [approximately]40 km. The primary lateral heterogeneity is caused by a major Lower Cretaceous deltaic system that emanated southwest of the Serrania del Interior. All important intervals, such as the laterally variable Aptian-Albian El Cantil platform limestone and the hydrocarbon source rocks of the Upper Cretaceous Querecual and San Antonio formations, are related to probable causal mechanisms and environmental conditions. Stratigraphic events have been interpreted as of either local or regional extent; based on a combination of outcrop sedimentologic analyses and regional depositional systems interpretation. The 3-dimensional distribution of depositional systems and systems tracts reveals 4-6 regional sequence boundaries separated by 4-20 m.y. Subsidence analyses support the facies interpretation of a passive margin by showing continuous, thermally dominated subsidence during the Cretaceous to Eocene interval. Subsidence and accumulation rates increased and facies changed significantly in the Oligocene, indicating the end of passive margin sedimentation and the initiation of foredeep subsidence and accumulation associated with overthrusting the eastward-advancing Caribbean Plate.

Erikson, J.P. (Dartmouth College, Hanover, NH (United States))

1993-02-01

175

Confronting Health Disparities: Latin American Social Medicine in Venezuela  

PubMed Central

Objectives. We explored the emergence and effectiveness of Venezuela's Misión Barrio Adentro, “Inside the Neighborhood Mission,” a program designed to improve access to health care among underserved residents of the country, hoping to draw lessons to apply to future attempts to address acute health disparities. Methods. We conducted our study in 3 capital-region neighborhoods, 2 small cities, and 2 rural areas, combining systematic observations with interviews of 221 residents, 41 health professionals, and 28 government officials. We surveyed 177 female and 91 male heads of household. Results. Interviews suggested that Misión Barrio Adentro emerged from creative interactions between policymakers, clinicians, community workers, and residents, adopting flexible, problem-solving strategies. In addition, data indicated that egalitarian physician–patient relationships and the direct involvement of local health committees overcame distrust and generated popular support for the program. Media and opposition antagonism complicated physicians’ lives and clinical practices but heightened the program's visibility. Conclusions. Top-down and bottom-up efforts are less effective than “horizontal” collaborations between professionals and residents in underserved communities. Direct, local involvement can generate creative and dynamic efforts to address acute health disparities in these areas. PMID:19150916

Mantini-Briggs, Clara

2009-01-01

176

New insights into chloramphenicol biosynthesis in Streptomyces venezuelae ATCC 10712.  

PubMed

Comparative genome analysis revealed seven uncharacterized genes, sven0909 to sven0915, adjacent to the previously identified chloramphenicol biosynthetic gene cluster (sven0916-sven0928) of Streptomyces venezuelae strain ATCC 10712 that was absent in a closely related Streptomyces strain that does not produce chloramphenicol. Transcriptional analysis suggested that three of these genes might be involved in chloramphenicol production, a prediction confirmed by the construction of deletion mutants. These three genes encode a cluster-associated transcriptional activator (Sven0913), a phosphopantetheinyl transferase (Sven0914), and a Na(+)/H(+) antiporter (Sven0915). Bioinformatic analysis also revealed the presence of a previously undetected gene, sven0925, embedded within the chloramphenicol biosynthetic gene cluster that appears to encode an acyl carrier protein, bringing the number of new genes likely to be involved in chloramphenicol production to four. Microarray experiments and synteny comparisons also suggest that sven0929 is part of the biosynthetic gene cluster. This has allowed us to propose an updated and revised version of the chloramphenicol biosynthetic pathway. PMID:25267678

Fernández-Martínez, Lorena T; Borsetto, Chiara; Gomez-Escribano, Juan Pablo; Bibb, Maureen J; Al-Bassam, Mahmoud M; Chandra, Govind; Bibb, Mervyn J

2014-12-01

177

Chemostratigraphy: Applications in the Tachira depression, Tachira State, Venezuela  

SciTech Connect

Rock analyses (40 chemical parameters) from densely sampled Cretaceous sections from La Luna, Navay, Aguardiente and Escandalosa formations in southwestern Venezuela, combined with multivariate statistical analysis, allowed statistical characterization of formations, environmentally meaningful clustering of correlated geochemical variables, as well as calculation of chemical accumulation rates. Chemofacies, defined from accumulation rates, were used for correlation and depositional environment definition. Organic matter maturity does not affect NiN ratios, but causes homogenization in Ca/Sr ratios. Th/V ratios clearly separate shelf vs. oceanic fades, closely matching those from biofacies analysis. Cycles in Th/V repeat every 60 in (Navay) to 20 in (La Luna), corresponding to Milankovitch climatic cycles. Shales (high Th/V) represent cooler-shallower sedimentation periods, and lodestones (low Th/V) represent warmer-deeper ones. Differences in accumulation rates were used for establishing changes in: source rock (La-Ce), either due to tectonism or variations in marine current pattern; redox conditions (Ni-V); clay mineralogy (Al-K); energy level (Al-Si); and salinity (Mg-Na). Finally, chemostratigraphy, combined with reliable structural and stratigraphical field data, has proven to be a powerful tool for unravelling tectono-stratigraphical histories.

Briceno, H.; Ostos, M.; Yoris, F. [Caracas (Venezuela)] [and others

1996-08-01

178

Late quaternary environmental history of lake valencia, Venezuela.  

PubMed

Chemical, paleontological, and mineralogical analyses of a 7.5-meter core from the middle of Lake Valencia, Venezuela, have provided information on the paleoclimatic history of this low-elevation, low-latitude site for the last 13,000 years. The data show that dry climates existed in this region from 13,000 years before present (B.P.) until about 10,000 years B.P. The Lake Valencia Basin was occupied by intermittent saline marshes at that time. About 10,000 years B.P., a permanent lake of fluctuating salinity formed and arboreal plant communities replaced the earlier dominant xeric herbaceous vegetation and marsh plants. By 8500 years B.P., Lake Valencia reached moderate to low salinities and discharged water; the modern vegetation became established at that time. After 8500 years B.P., the lake twice ceased discharging as a result of reduced watershed moisture. The second of these drying episodes is still in progress and has been aggravated by human activities in the watershed. PMID:17812244

Bradbury, J P; Leyden, B; Salgado-Labouriau, M; Lewis, W M; Schubert, C; Binford, M W; Frey, D G; Whitehead, D R; Weibezahn, F H

1981-12-18

179

New Insights into Chloramphenicol Biosynthesis in Streptomyces venezuelae ATCC 10712  

PubMed Central

Comparative genome analysis revealed seven uncharacterized genes, sven0909 to sven0915, adjacent to the previously identified chloramphenicol biosynthetic gene cluster (sven0916–sven0928) of Streptomyces venezuelae strain ATCC 10712 that was absent in a closely related Streptomyces strain that does not produce chloramphenicol. Transcriptional analysis suggested that three of these genes might be involved in chloramphenicol production, a prediction confirmed by the construction of deletion mutants. These three genes encode a cluster-associated transcriptional activator (Sven0913), a phosphopantetheinyl transferase (Sven0914), and a Na+/H+ antiporter (Sven0915). Bioinformatic analysis also revealed the presence of a previously undetected gene, sven0925, embedded within the chloramphenicol biosynthetic gene cluster that appears to encode an acyl carrier protein, bringing the number of new genes likely to be involved in chloramphenicol production to four. Microarray experiments and synteny comparisons also suggest that sven0929 is part of the biosynthetic gene cluster. This has allowed us to propose an updated and revised version of the chloramphenicol biosynthetic pathway. PMID:25267678

Fernández-Martínez, Lorena T.; Borsetto, Chiara; Gomez-Escribano, Juan Pablo; Bibb, Maureen J.; Al-Bassam, Mahmoud M.; Chandra, Govind

2014-01-01

180

STSHV a teleinformatic system for historic seismology in Venezuela  

NASA Astrophysics Data System (ADS)

From 1997 on, when the first "Jornadas Venezolanas de Sismicidad Historica" took place, a big interest awoke in Venezuela to organize the available information related to historic earthquakes. At that moment only existed one published historic earthquake catalogue, that from Centeno Grau published the first time in 1949. That catalogue had no references about the sources of information. Other catalogues existed but they were internal reports for the petroleum companies and therefore difficult to access. In 2000 Grases et al reedited the Centeno-Grau catalogue, it ended up in a new, very complete catalogue with all the sources well referenced and updated. The next step to organize historic seismicity data was, from 2004 to 2008, the creation of the STSHV (Sistema de teleinformacion de Sismologia Historica Venezolana, http://sismicidad.hacer.ula.ve ). The idea was to bring together all information about destructive historic earthquakes in Venezuela in one place in the internet so it could be accessed easily by a widespread public. There are two ways to access the system. The first one, selecting an earthquake or a list of earthquakes, and the second one, selecting an information source or a list of sources. For each earthquake there is a summary of general information and additional materials: a list with the source parameters published by different authors, a list with intensities assessed by different authors, a list of information sources, a short text summarizing the historic situation at the time of the earthquake and a list of pictures if available. There are searching facilities for the seismic events and dynamic maps can be created. The information sources are classified in: books, handwritten documents, transcription of handwritten documents, documents published in books, journals and congress memories, newspapers, seismologic catalogues and electronic sources. There are facilities to find specific documents or lists of documents with common characteristics. For each document general information is displayed together with an extract of the information relating to the earthquake. If the complete document was available and no problem with the publishers rights a pdf copy of the document was included. We found this system extremely useful for studying historic earthquakes, as one can access immediately previous research works about an earthquake and it allows to check easily the historic information and so to validate the intensity data. So far, the intensity data have not been completed for earthquakes after 2000. This information would be important for improving calibration of intensity - magnitude calibrations of historic events, and is a work in progress. On the other hand, it is important to mention that "El Catálogo Sismológico Venezolano del siglo XX" (The Seismological Venezuelan Catalog), published in 2012, updates seismic information up to 2007, and that the STSHV was one of its primary sources of information.

Choy, J. E.; Palme, C.; Altez, R.; Aranguren, R.; Guada, C.; Silva, J.

2013-05-01

181

Neogene history of the Carapita Formation, Eastern Venezuela basin  

NASA Astrophysics Data System (ADS)

The planktonic and benthic foraminifera from the lower to middle Miocene shales of the Carapita Formation of Eastern Venezuela in three exploration wells and one outcrop section are analyzed with the objectives of establishing a precise biostratigraphy of the formation and its bathymetric history. Comparison with the well-preserved microfaunas of the correlative Cipero Formation of Trinidad made possible the achievement of these objectives. The formation, up to 4500 to 6000 m thick in outcrops, extends from northeastern Anzoategui and North of Monagas States to the Gulf of Paria and is both an important oil reservoir towards the east and the main seal rock for the Oligocene reservoir in the north of Monagas State. In the area studied the Carapita Formation spans lower to lower middle Miocene Zones N6/M3 to N9/M6; its upper part is unconstrained as only rare long ranging early Miocene to early Pliocene planktonic foraminifera occur above the Orbulina datum. Unexpectedly, we found that the four lower to middle Miocene sections are highly discontinuous, with hiastuses as long as 4 Myr. Based on the abundance patterns of sixty-nine species of benthic foraminifera and analysis of morphotype abundance following the methodology of Corliss and Chen (1988) and Corliss and Fois (1993), we show that the Carapita Formation was deposited at outer neritic to middle bathyal depths (?200--1000 m), whereas the Cipero Formation was deposited at middle to lower bathyal depths (?600--2000 m). Importantly, the bathymetric changes are associated with unconformities in all sections, strongly suggesting that both (shallowing and associated unconformities) were tectonically induced.

Sanchez Zambrano, Dennis Alberto

182

Lithospheric scale model of Merida Andes, Venezuela (GIAME Project)  

NASA Astrophysics Data System (ADS)

Merida Andes (MA) is one of the most important orogenic belt in Venezuela and represents the northern culmination of South America Andes. During the last 60 years, several models have been proposed to explain the shallow and deep structure, using different geological, geophysical, seismological, geochemical and petrologic concepts; nevertheless, most of them have applied local observation windows, and do not represent the major structure of MA. Therefore, a multidisciplinary research group, coordinated by FUNVISIS, in close cooperation with UCV, ULA and PDVSA, is proposed in order to get the outlined goals in the project entitled GIAME ("Geociencia Integral de los Andes de MErida") was established, which aims to generate a lithospheric scale model and the development of a temporal dynamic model for the MA. As a base for lithospheric investigations of the Merida Andes, we are proposing three wide angle seismic profiles across the orogen on three representative sites, in order to determine the inner structure and its relation with the orogen's gravimetric root. To the date, there are no seismic studies at lithospheric scale which cross MA. The wide angle seismic will be complemented with the re-processing and re-interpretation of existing reflection seismic data, which will allow to establish a relationship between MA and its associated flexural basins (Maracaibo and Barinas-Apure basins). Depending on the results of the VENCORP Project (VENezuelan COntinental Reflection Profiling), which might show some reliable results about crustal features and Moho reflectors along three long seismic profiles at Caribbean Moutain system, a reflection seismic profile across the central portion of MA is proposed. Additional tasks, consisting in MA quaternary deformation studies, using research methods like neotectonics and paleoseismology, georadar, numerical modeling, cinematic GPS, SAR interferometry, thermocronology, detailed studies on regional geology, flexural modeling, gravity modeling, among others, will be carried out. We expect this project is going to help to solve many of the doubts regarding the origin, evolution and structural configuration of the Merida Andes.

Schmitz, M.; Orihuela, N. D.; Klarica, S.; Gil, E.; Levander, A.; Audemard, F. A.; Mazuera, F.; Avila, J.

2013-05-01

183

Vertical fluxes of particulate biogenic material through the euphotic and twilight zones in the Cariaco Basin, Venezuela  

E-print Network

in the Cariaco Basin, Venezuela Enrique Montes a,n , Frank Muller-Karger a , Robert Thunell b , David Hollander, Venezuela a r t i c l e i n f o Article history: Received 2 May 2011 Received in revised form 5 May 2012

Meyers, Steven D.

184

RESIDUOS DE PLAGUICIDAS ORGANOCLORADOS Y ORGANOFOSFORADOS EN EL CULTIVO DE CEBOLLA EN LA DEPRESIÓN DE QUÍBOR, VENEZUELA  

Microsoft Academic Search

Residues of organochlorines and organophosphorus pesticides in onion crop in Quibor depression, Venezuela The accumulation in onion crops of organophosphorus (OF) and organochlorines (OC) pesticide residues in production systems that used pest chemical control in Quíbor Depression, Lara State, Venezuela, was evaluated. Three representative onion production systems were selected, registering all types of pesticides used during the crop cycle. At

Francis Pierre; Pedro Betancourt

2007-01-01

185

Holocene evolution of the western Orinoco Delta, Venezuela  

USGS Publications Warehouse

The pristine nature of the Orinoco Delta of eastern Venezuela provides unique opportunities to study the geologic processes and environments of a major tropical delta. Remote-sensing images, shallow cores, and radiocarbon-dating of organic remains form the basis for describing deltaic environments and interpreting the Holocene history of the delta. The Orinoco Delta can be subdivided into two major sectors. The southeast sector is dominated by the Rio Grande-the principal distributary-and complex networks of anastomosing fluvial and tidal channels. The abundance of siliciclastic deposits suggests that fluvial processes such as over-bank flooding strongly influence this part of the delta. In contrast, the northwest sector is represented by few major distributaries, and overbank sedimentation is less widespread relative to the southeast sector. Peat is abundant and occurs in herbaceous and forested swamps that are individually up to 200 km2 in area. Northwest-directed littoral currents transport large volumes of suspended sediment and produce prominent mudcapes along the northwest coast. Mapping of surface sediments, vegetation, and major landforms identified four principal geomorphic systems within the western delta plain: (1) distributary channels, (2) interdistributary flood basins, (3) fluvial-marine transitional environments, and (4) marine-influenced coastal environments. Coring and radiocarbon dating of deltaic deposits show that the northern delta shoreline has prograded 20-30 km during the late Holocene sea-level highstand. Progradation has been accomplished by a combination of distributary avulsion and mudcape progradation. This style of deltaic progradation differs markedly from other deltas such as the Mississippi where distributary avulsion leads to coastal land loss, rather than shoreline progradation. The key difference is that the Orinoco Delta coastal zone receives prodigious amounts of sediment from northwest-moving littoral currents that transport sediment from as far away as the Amazon system (???1600 km). Late Holocene progradation of the delta has decreased delta-plain gradients, increased water levels, and minimized over-bank flooding and siliciclastic sedimentation in the northwest sector. These conditions, coupled with large amounts of direct precipitation, have led to widespread peat accumulation in interdistributary basins. Because peat-forming environments cover up to 5000 km2 of the delta plain, the Orinoco may be an excellent analogue for interpreting ancient deltaic peat deposits.

Aslan, A.; White, W.A.; Warne, A.G.; Guevara, E.H.

2003-01-01

186

Seismic microzoning projects and their implementation in Venezuela  

NASA Astrophysics Data System (ADS)

Site effects have been recognized to play an important role in damage distribution of destructive earthquakes. These effects have been observed in Venezuela especially during the 1967 Caracas earthquake, when 4 buildings with 10 and more storeys during the Caracas 1967 earthquake collapsed, and a big number of them in the same deep sediment area have been seriously damaged. This motivated the development of studies regarding the subsurface configuration of Caracas and Barquisimeto during the last decade, with a seismic microzoning project realized in both cities from 2005 to 2009. The main results of this project were the development of design response spectra for the different microzones within the sedimentary basin, as well as estimates of landslide hazard. Implementation of the results in municipality ordinances is actually discussed with local authorities. They are aimed to address mitigation for new constructions by the application of the specific design spectra, for existing buildings via evaluation and retrofitting strategies, and for slope areas (informal, as well as formal developments) due to the identification of areas that may not be developed or require detailed studies of slope stabilities. Since then, seismic microzoning studies were started in Cumaná, Guarenas/Guatire and Lara state, and within a broader context of integrated risk management, which includes flooding, landslide and technological risks, in Mérida, Valencia, Maracay, Barcelona/Puerto La Cruz and Valle de la Pascua. The projects are coordinated by the Venezuelan Foundation for Seismological Research (FUNVISIS) in cooperation with local universities. Efforts are done to unable local researchers to apply the methodologies in other cities as Valera, Trujillo, Boconó, San Cristóbal and Tucacas. A unified seismic hazard map as input motion to these studies is actually in development. Depending on the local characteristics, building inventory and vulnerability analysis are done for risk analysis. Further members of the "Grupo de trabajo: Investigaciones aplicadas a la gestion integral del riesgo en espacios urbanos" are: Oscar Andrés López, Milgreya Cerrada, Rafael Torres, Oscar Ramírez, Elieser Sanzonetti, José Heredia, Jaime Avendaño, Fernando Mazuera, Luis Molina, Alexi Suárez, Víctor Rocabado, Mónica Paolini, Luis Yegres, Leonardo Alvarado, Herbert Rendón, Luz Rodríguez, Jorge González.

Schmitz, M.; Cano, V.; Olbrich, F.; Vallee, M.; Morales, C.; Arreaza, A.; Mendes, K.; Klarica, S.; Alvarez Gomez, J.; Aray, J.; Vielma, J.; Pombo, A.; Diaz, J.; Grupo de trabajo

2013-05-01

187

CONDICIONES DE TRABAJO EN VENEZUELA EN EL PERODO 1999-2005: ELEMENTOS PARA UN BALANCE DE LA CUESTIN LABORAL EN EL PROCESO BOLIVARIANO  

E-print Network

CONDICIONES DE TRABAJO EN VENEZUELA EN EL PERÍODO 1999-2005: ELEMENTOS PARA UN BALANCE DE LA; informalidad; desempleo; salarios. #12;1. Introducción: el proyecto económico del proceso bolivariano Venezuela vigor de la nueva Constitución de 1999, en Venezuela se ha abierto un espacio político fabuloso donde el

Paris-Sud XI, Université de

188

GARRAPATAS (ACARI: IXODIDAE) RECOLECTADAS DE CANINOS BAJO ASISTENCIA VETERINARIA EN MARACAIBO, VENEZUELA. Ticks (Acari: Ixodidae) Collected From Canines Under Veterinary Care in Maracaibo, Venezuela  

Microsoft Academic Search

LUZ) in Maracaibo, Venezuela. For this, were collected 624 ticks from 64 dogs, those were identified. All of them were identified as Rhipicephalus sanguineus. The mean intensity was 9.8 ticks per dog (range: 2-55). Were collected 366 ticks female and 258 ticks male. Sexual ratio (male:female) was 1:1.4. There were 33 (51.69%) male dogs parasitized and 31 (48.4%) female dogs.

Roger A. Ramírez-Barrios; Everts Chacín; Glen Barboza; Gibson Fernández; Zulayne Valera; Alberto Villalobos; Francisco Angulo-Cubillán

2008-01-01

189

THE MARKET FOR BROILERS THROUGH FAST-FOOD OUTLETS IN VENEZUELA  

Microsoft Academic Search

PROAGRO is the leading firm in the broiler business in Venezuela. It is integrated through hatchery, grow-out, processing and distribution activities. As a consequence of strict price regulation policies enforced by the government in the poultry products, PROAGRO experienced serious injury to its profitability over the last few years. The most severe regulations were applied to PROAGRO's chief product (whole,

Jose E. Gomez

1978-01-01

190

The Boscan Field-Venezuela's giant stratigraphic trap with a complex history  

Microsoft Academic Search

The Boscan Field lies in the northwest quadrant of the Maracaibo Basin, Venezuela. It is a large stratigraphic trap that has produced more than 800 million barrels of heavy oil since 1946, principally from Eocene fluvial-deltaic clastic reservoirs. These are faulted, folded, and are truncated by a pre-Oligocene unconformity. The geochronology of the Boscan Field has been interpreted as follows:

D. C. Swanson; J. Jaimes; C. Valdez; B. Pirela; F. Puche; D. Rojas; E. Moya

1993-01-01

191

The nitrogen cycle in a ‘Terra Firme’ rainforest on oxisol in the Amazon territory of Venezuela  

Microsoft Academic Search

Standing stocks and fluxes of nitrogen, including nitrogen fixation and denitrification, were measured in a tropical rainforest on Oxisol in the Amazon Territory of Venezuela. The standing stock of nitrogen was comparable to that of temperate forests, but was higher than that in an adjacent forest on Spodosol. Fluxes were higher than in forests in the temperate zone, but lower

C. Jordan; W. Caskey; G. Escalante; R. Herrera; F. Montagnini; R. Todd; C. Uhl

1982-01-01

192

The Bolivarian University of Venezuela: A Radical Alternative in the Global Field of Higher Education?  

ERIC Educational Resources Information Center

This article discusses paradoxes in the emergent global field of higher education as reflected in an alternative model of the university--the Bolivarian University of Venezuela (UBV) and the related higher education policy, Mision Sucre. With its credo in the applied social sciences, its commitment to popular pedagogy and its dependence on…

Ivancheva, Mariya

2013-01-01

193

TOXOPLASMA GONDII INFECTIONS IN CHICKENS FROM VENEZUELA: ISOLATION, TISSUE DISTRIBUTION, AND MOLECULAR CHARACTERIZATION.  

Technology Transfer Automated Retrieval System (TEKTRAN)

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 46 free-range chickens (Gallus domesticus) from Venezuela was determined. Antibodies to T. gondii ...

194

The Effect of Wage Compression and Alternative Labor Market Opportunities on Teacher Quality in Venezuela  

ERIC Educational Resources Information Center

This paper examines the effect of teacher relative wages and teacher wage dispersion on high school graduates' preferences for teaching majors in College. This approximation to teacher quality is appropriate in a country like Venezuela as opposed to the US since the rigidity of the tertiary school system significantly limits mobility between…

Ortega, Daniel E.

2010-01-01

195

Five Years of Cyclotron Radioisotope Production Experiences at the First PET-CT in Venezuela  

SciTech Connect

Five years operation of a compact cyclotron installed at PET-CT facility in Caracas, Venezuela is given. Production rate of {sup 18}F labeled FDG, operation and radiation monitoring experience are included. We conclude that {sup 18}FDG CT-PET is the most effective technique for patient diagnosis.

Colmenter, L.; Coelho, D.; Esteves, L. M.; Ruiz, N.; Morales, L.; Lugo, I. [Centro Diagnostico Docente, Las Mercedes, Caracas (Venezuela); Sajo-Bohus, L.; Liendo, J. A.; Greaves, E. D.; Barros, H. [Universidad Simon Bolivar, Seccion de Fisica Nuclear, Caracas (Venezuela); Castillo, J. [University of Applied Science of Aachen (Germany)

2007-10-26

196

Levels, chemical fractionation, and solubility of lead in roadside soils of Caracas, Venezuela  

Microsoft Academic Search

The author investigated the level, chemical fractions, and solubility of Pb in several roadside soils of heavily traveled areas of Caracas, Venezuela. Using 1 N HNOâ extraction, he studied the levels of lead in 25 roadside soil samples and found a very high level of Pb (average enrichment factor 21.0), indicating a strong lead pollution of Caracas roadside soils by

J. GARCIA-MIRAGAYA

1984-01-01

197

Teachers' Perceived Efficacy among English as a Foreign Language Teachers in Middle Schools in Venezuela  

ERIC Educational Resources Information Center

Teachers' sense of efficacy has been shown to influence teachers' actions and student outcomes. This study explored self-efficacy beliefs among English as a Foreign Language teachers in selected schools in Venezuela. Data were collected through a survey administered to 100 teachers. The Teacher Sense of Efficacy Scale (Tschannen-Moran & Woolfolk…

Chacon, C.T.

2005-01-01

198

Phytomass structure of natural plant communities on spodosols in southern Venezuela: The tall Amazon Caatinga forest  

Microsoft Academic Search

The phytomass structure of the evergreen lowland forest vegetation (Tall Amazon Caatinga) supported by tropaquods near San Carlos de Rio Negro, Federal Amazon Territory of Venezuela was studied in 13 10 m× 10 m plots. The plots were laid out subjectively to cover a low topographical gradient along which the forest on tropaquod is grading into a low woodland (Bana,

H. Klinge; R. Herrera

1983-01-01

199

The Population Structure of Red Howler Monkeys (Alouatta seniculus) in Trinidad and Venezuela  

Microsoft Academic Search

The small troops and roughly even adult sexual ratio of Alouatta seniculus, studied in Bush Bush Forest in Trinidad and on the ranch Hato Masaguaral in the llanos of Venezuela, are more similar to A. caraya than to A. palliata. Other aspects of the troop composition are discussed. Though the red howler prefers certain types of habitat including tall trees,

M. K. Neville

1972-01-01

200

Counter-Hegemonic Regionalism and Higher Education for All: Venezuela and the ALBA  

ERIC Educational Resources Information Center

This paper employs new regionalism theory and regulatory regionalism theory in its analysis and theorisation of the Bolivarian Alliance for the Peoples of Our America (ALBA) as a counter-hegemonic Latin American and Caribbean (LAC) regionalism. As (initially) the regionalisation of Venezuela's Bolivarian Revolution, ALBA is centred around the idea…

Muhr, Thomas

2010-01-01

201

ACUTE CHAGAS' DISEASE IN WESTERN VENEZUELA: A CLINICAL, SEROPARASITOLOGIC, AND EPIDEMIOLOGIC STUDY  

Microsoft Academic Search

A clinical, parasitologic, and serologic study carried out between 1988 and 1996 on 59 acute-phase patients in areas of western Venezuela where Chagas' disease is endemic showed 19 symptomatic patterns or groups of symptoms appearing in combination with different frequencies. The symptomatic pattern with the highest frequency was that showing simultaneously fever, myalgia, headache, and Romana's sign, which was detected

NESTOR ANEZ; HUGO CARRASCO; HENRY PARADA; GLADYS CRISANTE; AGUSTINA ROJAS; NESTOR GONZALEZ; JOSE LUIS RAMIREZ; PALMIRA GUEVARA; CHRISTIAN RIVERO; RAFAEL BORGES; JOSE VICENTE SCORZA

202

A Gene Cluster for Macrolide Antibiotic Biosynthesis in Streptomyces venezuelae: Architecture of Metabolic Diversity  

Microsoft Academic Search

In a survey of microbial systems capable of generating unusual metabolite structural variability, Streptomyces venezuelae ATCC 15439 is notable in its ability to produce two distinct groups of macrolide antibiotics. Methymycin and neomethymycin are derived from the 12-membered ring macrolactone 10-deoxymethynolide, whereas narbomycin and pikromycin are derived from the 14-membered ring macrolactone, narbonolide. This report describes the cloning and characterization

Yongquan Xue; Lishan Zhao; Hung-Wen Liu; David H. Sherman

1998-01-01

203

Comprehensive Education Bolivarian-Style: The Alternative School in Barrio Pueblo Nuevo, Venezuela  

ERIC Educational Resources Information Center

In this article, the author traces revolutionary developments in an alternative school in Barrio Pueblo Nuevo, Mérida, in the Bolivarian Republic of Venezuela, a school that caters for students between 4 and 14. He begins by recounting some fieldwork done at the school on his behalf by Edward Ellis in 2010. He goes on to discuss a video made at…

Cole, Mike

2014-01-01

204

UNA NUEVA ESPECIE DE PROCTOPORUS (SAURIA: GYMNOPHTHALMIDAE) DE LOS ANDES DE VENEZUELA  

Microsoft Academic Search

A new species is described of lizard of the genus Proctoporus, belonging to the P. luctuosus group and closely related whith P. achlyens and P. shrevei, from the Cordillera de la Costa de Venezuela and Trinidad Island respectively. This species, an inhabitant in the terminal branches of the Cordillera de Mérida South of the Depresión de Barquisimeto, is the first

Juan Elías GARCIA-PEREZ; Enrique Elías YUSTIZ

205

Formation of the Maturín Foreland Basin, eastern Venezuela: Thrust sheet loading or subduction dynamic topography  

NASA Astrophysics Data System (ADS)

The Maturín Basin in eastern Venezuela is considered a good example of a peripheral foreland basin. Earthquake and tomographic data indicate that eastern Venezuela is affected by the oblique subduction of the South American Plate underneath the Caribbean Plate. New forward flexural isostatic modeling of eastern Venezuela has been carried out in order to determine whether the Maturín Basin was generated purely by thrust sheet loading from the Serranía and Monagas Foreland Thrust Belts. A sequence of forward models from middle Miocene to Present was generated for 3 profiles across the Serranía del Interior Thrust Belt, the Monagas Foreland Thrust Belt, and the Maturín Foreland Basin. The predictions of these models are constrained using seismic reflection and well data. The flexural isostatic modeling shows that thrust sheet loading associated with the Serranía del Interior and Monagas Foreland thrust belts is insufficient to generate the observed subsidence within the Maturín Basin. Dynamic fluid flow modeling of subduction related dynamic topography of eastern Venezuela has been used to investigate the influence of South American Plate subduction on the generation of the accommodation space observed in the Maturín Basin. Fluid flow modeling of subduction related dynamic topography suggests that the subduction of the South American lithospheric mantle caused downward deflection of the South American crust affecting the Maturín Basin and the Serranía Thrust Belt. This modeling suggests that the Maturín Basin subsidence has two components: 55% related to thrust sheet loading and 45% driven by continental subduction.

JáCome, Maria I.; Kusznir, Nick; Audemard, Felipe; Flint, Steve

2003-10-01

206

Modern climate forcing of terrigenous deposition in the tropics (Cariaco Basin, Venezuela)  

Microsoft Academic Search

One approach to deciphering tropical Quaternary paleoclimate records has been to study the composition of terrigenous material in order to infer past changes in hydrologic and atmospheric conditions. Here we present the inorganic geochemistry (major and trace elements) of modern sediment traps and shelf sediments in the tropical Cariaco Basin, Venezuela, in order to characterize seasonal variation in deposition of

Nahysa C. Martinez; R. W. Murray; Robert C. Thunell; Larry C. Peterson; Frank Muller-Karger; Yrene Astor; Ramon Varela

2007-01-01

207

Early Sexual Maturity Among Pume Foragers of Venezuela: Fitness Implications of Teen Motherhood  

E-print Network

Early Sexual Maturity Among Pume´ Foragers of Venezuela: Fitness Implications of Teen Motherhood their late teens. Am J Phys Anthropol 136:338­350, 2008. VVC 2008 Wiley-Liss, Inc. Age at first birth is tied biology literature on teen pregnancy, objectives are to first to describe these patterns and then discuss

Kramer, Karen L.

208

The Peasantry as an Emerging Political Factor in Mexico, Bolivia, and Venezuela.  

ERIC Educational Resources Information Center

This study examines the potential role of the peasantry in the determination of political power in Latin America. Case studies of Mexico, Bolivia, and Venezuela illustrate that the framework of political change is of major importance because it is crucial in determining the properties of the political system to follow. The previous involvement of…

Lord, Peter P.

209

Applications of Planktonic foraminifera in the Paleogene of the Eastern Venezuela-Trinidad Basin  

Microsoft Academic Search

Following increased interest in the petroleum potential of the Eastern Venezuela-Trinidad Basin, a revision of the planktonic foraminifera from the Paleogene was undertaken. The application of evolutionary trends in microperforate, medioperforate and macroperforate lineages for petroleum exploration is assessed. Scanning Electron Microscope illustrations are presented for over 100 taxa currently applied in high resolution biostratigraphy, sequence stratigraphy and paleoceanography of

1996-01-01

210

Teachers’ perceived efficacy among English as a foreign language teachers in middle schools in Venezuela  

Microsoft Academic Search

Teachers’ sense of efficacy has been shown to influence teachers’ actions and student outcomes. This study explored self-efficacy beliefs among English as a Foreign Language teachers in selected schools in Venezuela. Data were collected through a survey administered to 100 teachers. The Teacher Sense of Efficacy Scale (Tschannen-Moran & Woolfolk Hoy, 2001) was used to assess efficacy for management, engagement,

Carmen Teresa Chacón

2005-01-01

211

Factors Affecting Student Success at the National Open University of Venezuela.  

ERIC Educational Resources Information Center

Findings of this analysis of the effect of selected variables on attrition in the introductory course of the National Open University of Venezuela suggest that noninstitutional variables accounted for the largest proportion of variance of student completion. Counseling and course redesign are recommended to enhance student motivation to complete…

de Freitas, Katia Siqueira; Lynch, Patrick

1986-01-01

212

A modern regional geological analysis of Venezuela - lessons from a major new world oil province on exploration in mature areas  

SciTech Connect

Venezuela has produced some 44 billion bbl of oil since the early part of the century. As such, it represents one of the world's major oil producers and a mature petroleum province. However, major tracts of Venezuela's sedimentary basins remain underexplored and large discoveries are still being made in new and old reservoir systems. A regional geological analysis of Venezuela, focusing on basin evolution and sequence stratigraphy and incorporating data from the three national oil companies, is presented. The analysis presents a regionally consistent tectonostratigraphic model capable of explaining the evolution of the Mesozoic and Cenozoic basins of Venezuela and placing the major reservoir facies in their regional tectonic and sequence stratigraphic context. Four regional cross sections describe the stratigraphic and structural model. The model recognizes a Jurassic rifting event and inversion, succeeded by an Early Cretaceous passive margin. In western Venezuela, the Early Cretaceous passive subsidence is enhanced locally by extension related to the Colombian active margin. Venezuela experienced a major change in the Campanian with the initial collision of the Caribbean arc, recorded by foreland structuring and widespread stratigraphic changes. From the Campanian onward, the tectonostratigraphic evolution can be modeled in terms of a progressive southeast-directed arc-continent collision and the migration of the associated foredeep and rift basins. Within the tectonic framework, the major sequence stratigraphic units are identified and the reservoir distribution interpreted. This model provides a strong predictive tool to extrapolate reservoir systems into Venezuela's underexplored areas and to readdress its traditional areas.

Daly, M. (BP Exploracion de Venezuela, Stockley Park, Middlesex (United Kingdom)); Audemard, F. (Intevep, Miranda (Venezuela)); Valdes, G. (Petroleos de Venezuela, Caracas (Venezuela))

1993-09-01

213

Mycobacterium tuberculosis population structure and molecular epidemiological analysis in Sucre municipality, Miranda state, Venezuela.  

PubMed

Sucre municipality is a large, densely populated marginal area in the eastern part of Caracas, Venezuela that consistently has more cases of tuberculosis than other municipalities in the country. To identify the neighborhoods in the municipality with the highest prevalence of tuberculosis, and determine whether the Mycobacterium tuberculosis strain distribution in this municipality is different from that previously found in the western part of Caracas and the rest of Venezuela, we collected data on all tuberculosis cases in the municipality diagnosed in 2005-6. We performed two separate molecular epidemiological studies, spoligotyping 44 strains in a first study, and spoligotyping 131 strains, followed by MIRU-VNTR 15 on 21 clustered isolates in the second. With spoligotyping, the most common patterns were Shared International Type SIT17 (21%); SIT42 (15%); SIT93 (11%); SIT20 (7%); SIT53 (6%), a distribution similar to other parts of Venezuela, except that SIT42 and SIT20 were more common. MIRU-VNTR 15 showed that six of seven SIT17 strains examined belonged to a large cluster previously found circulating in Venezuela, but all of the SIT42 strains were related to a cluster centered in the neighborhoods of Unión and Maca, with a MIRU-VNTR pattern not previously seen in Venezuela. It appears that a large percentage of the tuberculosis in the Sucre municipality is caused by the active transmission of two strain families centered within distinct neighborhoods, one reflecting communication with the rest of the country, and the other suggesting the insular, isolated nature of some sectors. PMID:25558753

Patiño, Margareth A; Abadía, Edgar; Solalba Gómez; Maes, Mailis; Muñoz, Mariana; Gómez, Daniela; Guzmán, Patricia; Méndez, María Victoria; Ramirez, Carmen; Mercedes, España; de Waard, Jacobus; Takiff, Howard

2014-12-01

214

Neotropical genera of Naucoridae (Hemiptera: Heteroptera: Nepomorpha): new species of Placomerus and Procryphocricos from Guyana and Venezuela.  

PubMed

The Neotropical fauna of saucer bugs (Naucoridae) currently includes four monotypic genera. Recent extensive collecting in Venezuela has produced three new species in two of these genera. In addition, undetermined Guyanan specimens of one of the new species were found in the United States National Museum of Natural History. Thus, described here are Placomerus obscuratus n. sp. from Guyana and Venezuela with brachypterous and macropterous hindwing forms, and two species of Procryphocricos from Venezuela. Procryphocricos quiu n. sp. is described from the brachypterous forewing form and Procryphocricos macoita n. sp. from both brachypterous and macropterous forms. Previously described species also are discussed. PMID:24869509

Sites, Robert W; Camacho, Jesús

2014-01-01

215

Misión Madres Del Barrio: A Bolivarian Social Program Recognizing Housework and Creating A Caring Economy in Venezuela  

E-print Network

ABSTRACT: This thesis began as a project about Misión Madres del Barrio; and it quickly transformed into a glimpse of the Bolivarian Revolution underway in Venezuela. Misión Madres del Barrio (MMB) is one of the pioneering social programs...

Fischer-Hoffman, Cory

2008-08-20

216

Book Review: "Educational Reform and Administrative Development: The Cases of Columbia and Venezuela," by E. Mark Hanson.  

ERIC Educational Resources Information Center

Reviews "Educational Reform and Administrative Development: The Cases of Colombia and Venezuela," by E. Mark Hanson, which relates the policy-making and administrative structures of these two countries to their political, historical, and cultural contexts. (TE)

Lynch, Patrick D.

1988-01-01

217

Risk prevention and policy formulation : responding to the 1999 mud-floods catastrophe in El Litoral Central, Venezuela  

E-print Network

Fifteen days of constant and intense rainfall in Venezuela culminated on December 16 1999, in catastrophic landslides and flooding along 25 miles of the Vargas State coastal strip. This catastrophe ravaged the Caracas ...

Parisca-Blanco, Sonia

2005-01-01

218

Cloning and functional analysis of a phosphopantetheinyl transferase superfamily gene associated with jadomycin biosynthesis in Streptomyces venezuelae ISP5230  

Microsoft Academic Search

Sequence analysis of a XhoI\\/SacI fragment of chromosomal DNA downstream of jadL in the Streptomyces venezuelae ISP5230 gene cluster for jadomycin biosynthesis detected a partial ORF similar in its deduced amino acid sequence to the hetI product involved in synthesizing a regulator of heterocyst spacing in Anabaena. By probing a phage library of S. venezuelae DNA with the XhoI\\/SacI fragment,

Liru Wang; Jennifer McVeyã; Leo C. Vining

219

Household energy use in urban Venezuela: Implications from surveys in Maracaibo, Valencia, Merida, and Barcelona-Puerto La Cruz  

SciTech Connect

This report identifies the most important results of a comparative analysis of household commercial energy use in Venezuelan urban cities. The use of modern fuels is widespread among all cities. Cooking consumes the largest share of urban household energy use. The survey documents no use of biomass and a negligible use of kerosene for cooking. LPG, natural gas, and kerosene are the main fuels available. LPG is the fuel choice of low-income households in all cities except Maracaibo, where 40% of all households use natural gas. Electricity consumption in Venezuela`s urban households is remarkably high compared with the levels used in households in comparable Latin American countries and in households of industrialized nations which confront harsher climatic conditions and, therefore, use electricity for water and space heating. The penetration of appliances in Venezuela`s urban households is very high. The appliances available on the market are inefficient, and there are inefficient patterns of energy use among the population. Climate conditions and the urban built form all play important roles in determining the high level of energy consumption in Venezuelan urban households. It is important to acknowledge the opportunities for introducing energy efficiency and conservation in Venezuela`s residential sector, particularly given current economic and financial constraints, which may hamper the future provision of energy services.

Figueroa, M.J.; Sathaye, J.

1993-08-01

220

Review of the Berosus Leach of Venezuela (Coleoptera, Hydrophilidae, Berosini) with description of fourteen new species  

PubMed Central

Abstract The species of the water scavenger beetle genus Berosus Leach occurring in Venezuela are reviewed. Thirty-six species are recorded, including fifteen new species, fourteen of which are described here as new: Berosus aragua sp. n., Berosus asymmetricus sp. n., Berosus capanaparo sp. n., Berosus castaneus sp. n., Berosus corozo sp. n., Berosus ebeninus sp. n., Berosus garciai sp. n., Berosus humeralis sp. n., Berosus jolyi sp. n., Berosus llanensis sp. n., Berosus megaphallus sp. n., Berosus ornaticollis sp. n., Berosus repertus sp. n., and Berosus tramidrum sp. n. The fifteenth new species, known from a single female, is left undescribed pending the collection of males. Twelve species are recorded from Venezuela for the first time: Berosus ambogynus Mouchamps, Berosus consobrinus Knisch, Berosus elegans Knisch, Berosus geayi d’Orchymont, Berosus ghanicus d’Orchymont, Berosus guyanensis Queney, Berosus holdhausi Knisch, Berosus marquardti Knisch, Berosus olivae Queney, Berosus reticulatus Knisch, Berosus wintersteineri Knisch, and Berosus zimmermanni Knisch. PMID:22811607

Oliva, Adriana; Short, Andrew E. Z.

2012-01-01

221

New particle formation events observed at a high altitude site Pico Espejo, Venezuela  

NASA Astrophysics Data System (ADS)

Formation and growth events of nucleation mode particles (10-25 nm in diameter) were analyzed from 27 month period of particle size distribution measurements at the high altitude site Pico Espejo in Venezuela. Particle formation was observed both in air masses connected to boundary layer air and in free tropospheric conditions. The frequency and magnitude of particle formation at this high altitude site was comparable to many observations at lower altitude sites.

Nieminen, Tuomo; Kontkanen, Jenni; Krejci, Radovan; Ström, Johan; Tunved, Peter; Hamburger, Thomas; Calderon, Silvia; Hoffman, Pedro

2013-05-01

222

Shear-wave splitting in northeast Venezuela, Trinidad, and the eastern Caribbean  

Microsoft Academic Search

We present new measurements of splitting of core shear-wave phases (SKS, SKKS, PKS) recorded at seven stations in the eastern Caribbean region. Six stations in northeastern Venezuela and Trinidad constituted the SECaSA92 temporary broadband array. The seventh station, SJG, is installed on Puerto Rico. We also attempted to measure source-side splitting of S waves from earthquakes in the Lesser Antilles

R. M. Russo; P. G. Silver; M. Franke; W. B. Ambeh; D. E. James

1996-01-01

223

Chromoblastomycosis in children and adolescents in the endemic area of the Falcón State, Venezuela  

Microsoft Academic Search

The present paper describes 22 cases of chromoblastomycosis (CBM) caused by Cladophialophora carrionii in children and adolescents (2\\/19 years old). The patients were seen between 1992 and 2004 and all resided in a CBM endemic area in the semi-arid zone of the Falcon state, Venezuela. Twelve of the 22 patients (54.55%) had close relatives who also had CBM and 19

M. Pérez-Blanco; R. Hernández Valles; L. García-Humbría; F. Yegres

2006-01-01

224

Opportunities and constraints to biotechnological applications in the Caribbean: transgenic papayas in Jamaica and Venezuela.  

PubMed

In this opinion article, we briefly review the status of crop biotechnology research-with emphasis on the development of GM crops-in Jamaica and Venezuela. We focus on the transgenic papayas developed for both countries, and examine the factors hindering not only the development and application of this biotechnological commodity for the improvement of agricultural productivity, but also on the challenges influencing societal acceptance of the technology. PMID:21212960

Fermin, Gustavo; Tennant, Paula

2011-05-01

225

Applications of Planktonic foraminifera in the Paleogene of the Eastern Venezuela-Trinidad Basin  

SciTech Connect

Following increased interest in the petroleum potential of the Eastern Venezuela-Trinidad Basin, a revision of the planktonic foraminifera from the Paleogene was undertaken. The application of evolutionary trends in microperforate, medioperforate and macroperforate lineages for petroleum exploration is assessed. Scanning Electron Microscope illustrations are presented for over 100 taxa currently applied in high resolution biostratigraphy, sequence stratigraphy and paleoceanography of the region. These will allow more rapid and reliable recognition of zones, hiatuses and sequence boundaries.

Radford, S. [Department of Geology, Imperial College of Science, Technology and Medicine, London (United Kingdom)

1996-08-01

226

MICROBIAL ECOLOGY OF THE CARIACO BASIN'S REDOXCLINE: THE U.S.VENEZUELA CARIACO TIMES SERIES PROGRAM  

Microsoft Academic Search

The cooperative U.S.-Venezuela CARIACO program (CArbon Retention In A Colored Ocean) has begun to elucidate the microbial\\u000a ecology of the Cariaco Basin's redoxcline. This anoxicwater column supports highly stratified microbial assemblages of prokaryotes,\\u000a protozoa and viruses, exhibiting abundance and activity maxima near the O2\\/H2S interface. In the oxic layer, abundance and activity of microheterotrophs vary annually to the same extent

Gordon T. Taylor; Maria Iabichella-Armas; Ramon Varela; Frank Müller-Karger; Xueju Lin; Mary I. Scranton

227

Distribution, status, and traditional significance of the West Indian manatee Trichechus manatus in Venezuela  

USGS Publications Warehouse

Aerial and interview surveys were conducted in 1986 to determine the current distribution, status, and traditional significance of the West Indian manatee Trichechus manatus in Venezuela. Aerial surveys provided just eight tentative sightings in 73 hours of searching. These discouraging results may have been due to poor visibility, small populations, and perhaps reduced dry season manatee activity. Results of interview surveys, however, permitted a number of important generalizations. A remnant manatee population exists in Lake Maracaibo, but none occur along the more than 1500 km of Caribbean coastline. Abundance is greatest in eastern Venezuela bordering the Golfo de Paria, in the Orinoco Delta, and in the middle Orinoco and tributaries. Local market hunting in the middle of this century probably greatly reduced manatee populations in these areas. Recent protection laws, education efforts, and manatee scarcity have resulted in a declining interest in manatee hunting. Much excellent manatee habitat persists in these regions, and a continued decline in hunting could result in an optimistic outlook for future manatee populations if the incidental take in net fisheries is controlled. Traditional beliefs and legends concerning manatees in Venezuela, including hunting taboos, show that these animals remain a colorful part of the folk culture. However, manatee protection does not pose economic hardships or infringe upon traditional spiritual beliefs.

O'Shea, Thomas J.; Correa-Viana, Martín; Ludlow, Mark E.; Robinson, John G.

1988-01-01

228

Receiver Functions Imaging of the Moho and LAB in the Southern Caribbean plate boundary and Venezuela  

NASA Astrophysics Data System (ADS)

We have made teleseismic Ps and Sp receiver functions from data recorded from 2003 to 2009 by the permanent national seismic network of Venezuela, the BOLIVAR (Broadband Onshore-offshore Lithospheric Investigation of Venezuela and the Antilles arc Region) and WAVE (Western Array for Venezuela) experiments. The receiver functions show rapid variations in Moho and lithosphere-asthenosphere boundary (LAB) depths both across and along the southern Caribbean plate boundary region. We used a total of 69 events with Mw > 6 occurring at epicentral distances from 30° to 90° for the Ps receiver functions, and 43 events with Mw > 5.7 from 55° to 85° to make Sp receiver functions. For CCP stacking we constructed a 3D velocity model from numerous active source profiles (Schmitz et al., 2001; Bezada et al., 2007; Clark et al., 2008; Guedez, 2008; Magnani et al., 2009), from finite-frequency P wave upper mantle tomography model of Bezada et al., (2010) and the Rayleigh wave tomography model of Miller et al., (2009). The Moho ranges in depth from ~25 km beneath the Caribbean Large Igneous Provinces to ~55 km beneath the Mérida Andes in western Venezuela. These results are consistent with previous receiver functions studies (Niu et al., 2007) and the available active source profiles. Beneath the Maracaibo Block in northwestern Venezuela, we observe a strong positive signal at 40 to 60 km depth dipping ~6° towards the continent. We interpret this as the Moho of the Caribbean slab subducting beneath northernmost South America from the west. Beneath northern Colombia and northwestern Venezuela the top of this slab has been previously inferred from intermediate depth seismicity (Malavé and Suarez, 1995), which indicates a slab dipping between 20° - 30° beneath Lake Maracaibo. Our results could indicate that the slab is tearing beneath Lake Maracaibo as suggested previously by Masy et al. (2011). The deeper (> 100 km depth) part of the slab has been imaged using P-wave tomography (Bezada et al, 2010). Like others we attribute the uplift of the Mérida Andes to flat Caribbean slab subduction (for example Kellogg and Bonini, 1982). In central Venezuela beneath the Cordillera de la Costa we observe a positive signal shallower than the Moho at <30 km depth beneath the entire range. We interpret this as a detachment surface beneath Caribbean & arc terranes thrust onto the SA margin (Bezada et al., 2010). The lithosphere-asthenosphere boundary (LAB) beneath the Mérida Andes is shallow, ~65km depth, and parallels the range. In the plate boundary region under the Cordillera de la Costa the lithosphere is also thin, ~65km, beneath the Cariaco basin the lithosphere thickens to 85 km. In the far east under Serranía del Interior the lithosphere is ~75 km. Cratonic lithosphere thickness varies from 85 to 100 km.

Masy, J.; Levander, A.; Niu, F.

2011-12-01

229

Lithospheric Expressions of the Precambrian Shield, Mesozoic Rifting, and Cenozoic Subduction and Mountain Building in Venezuela  

NASA Astrophysics Data System (ADS)

The Caribbean (CAR)-South American (SA) plate boundary in Venezuela is a broad zone of faulting and diffuse deformation. GPS measurements show the CAR moving approximately 2 cm/yr relative to SA, parallel to the strike slip fault system in the east, with more oblique convergence in the west (Weber et al., 2001) causing the southern edge of the Caribbean to subduct beneath northwestern South America. The west is further complicated by the motion of the triangular Maracaibo block, which is escaping northeastward relative to SA along the Bocono and Santa Marta Faults. In central and eastern Venezuela, plate motion is accommodated by transpression and transtension along the right lateral San Sebastian- El Pilar strike-slip fault system. The strike-slip system marks the northern edge of coastal thrust belts and their associated foreland basins. The Archean-Proterozoic Guayana Shield, part of the Amazonian Craton, underlies southeastern and south-central Venezuela. We used the 87 station Venezuela-U.S. BOLIVAR array (Levander et al., 2006) to investigate lithospheric structure in northern South America. We combined finite-frequency Rayleigh wave tomography with Ps and Sp receiver functions to determine lithosphere-asthenosphere boundary (LAB) depth. We measured Rayleigh phase velocities from 45 earthquakes in the period band 20-100s. The phase velocities were inverted for 1D shear velocity structure on a 0.5 by 0.5 degree grid. Crustal thickness for the starting model was determined from active seismic experiments and receiver function analysis. The resulting 3D shear velocity model was then used to determine the depth of the LAB, and to CCP stack Ps and Sp receiver functions from ~45 earthquakes. The receiver functions were calculated in several frequency bands using iterative deconvolution and inverse filtering. Lithospheric thickness varies by more a factor of 2.5 across Venezuela. We can divide the lithosphere into several distinct provinces, with LAB depth reflecting the signatures of the Precambrian craton in the south, Mesozoic rifting in central Venezuela, and Neogene subduction and orogenesis in both the northeast and northwest. Specifically, LAB depth varies from 110-130 km beneath the Guayana Shield, in agreement with finite-frequency body wave tomography (Bezada et al., 2010b). To the north beneath the Serrania del Interior and Maturin Basin the Rayleigh waves image two high velocity features to depths of 200 km. The northernmost, beneath the Serrania, corresponds to the top of the subducting Atlantic plate, in agreement with P-wave tomography that images the Atlantic plate to transition zone depths. Another localized high velocity feature extending to ~200 km depth lies to the south. We speculate that this is a lithospheric drip caused by destabilization of the SA lithospheric caused by Atlantic subduction. Immediately to the west beneath the Cariaco basin the LAB is at ~50 km, marking the top of a pronounced low velocity zone. The thin lithosphere extends southwestward from the Cariaco Basin beneath the Mesozoic Espino Graben to the craton. To the west the LAB deepens to ~80 km beneath the Barinas Apure Basin and then to ~90 km beneath the Neogene Merida Andes and Maracaibo block.

Levander, A.; Masy, J.; Niu, F.

2013-05-01

230

Onchocerca-Simulium complexes in Venezuela: can human onchocerciasis spread outside its present endemic areas?  

PubMed

The compatibility between sympatric and allopatric combinations of Onchocerca volvulus-anthropophilic species of Simulium was studied in the north-eastern focus of human onchocerciasis as well as in a densely populated locality of the Amazonas State in Venezuela. The objectives were to test the conjecture that local adaptation exists between the parasite and its vectors (the Onchocerca-Simulium complex hypothesis), and assess the possibility of the infection spreading from its present distributional range. For the homologous combination, O. volvulus-S. metallicum cytospecies E in Anzoátegui State (north-eastern focus), parasite yield was 45% in contrast to 1% for the heterologous, southern parasite-S. metallicum infection. This was significantly lower than the parasite yield (4-10%) expected after allowing for the effect of density-dependent limitation of infective larval output described in this paper for S. metallicum. The population of S. exiguum s.l. from southern Venezuela allowed no larval development beyond the L1 stage of either northern or southern parasites. Mechanisms for such refractoriness probably operate at the level of the thoracic muscles, not affecting microfilarial uptake or migration out of the bloodmeal. The parasite yield of southern O. volvulus in S. oyapockense s.l. flies biting man at Puerto Ayacucho (Amazonas) was about 1%, in agreement with the figures recorded for highly compatible sympatric combinations such as O. volvulus-S. ochraceum s.l. in Guatemala. No infective larval development of the northern parasite was observed in southern S. oyapockense. These results, together with considerations of typical worm burdens in the human host, presence/absence of armed cibaria in the simuliids, parasite-induced vector mortality, and fly biting rates, suggest a lower potential for onchocerciasis to spread between the northern and southern endemic areas of Venezuela than that between Amazonian hyperendemic locations and settlements outside this focus with high densities of S. oyapockense s.l. PMID:10726276

Basáñez, M G; Yarzábal, L; Frontado, H L; Villamizar, N J

2000-02-01

231

Microseismicity evidence for subduction of the Caribbean plate beneath the South American Plate in northwestern Venezuela  

NASA Astrophysics Data System (ADS)

Over 1100 microearthquakes with body wave magnitude mb<4 have been located in western Venezuela and the southwestern Caribbean region since the installation in 1980 of the Venezuelan Seismological Array, together with 120 events of mb?4, one of them with surface wave magnitude Ms˜6. This tectonically complex region is part of the boundary between the Caribbean and the South American plates. The main seismically active feature inland in western Venezuela is the northeast striking, 600-km long, 100-km wide, right-lateral strike-slip Boconó fault zone along the Venezuelan Andes. About 80% of the earthquakes located in the entire region in the period 1980-mid-1995 have occurred on this fault zone, at focal depths <20 km. Microearthquake activity at lower rates also occurs northwest of the Venezuelan Andes, both in the continental and Caribbean sea regions. Part of this activity takes place at depths down to ˜150 km. Northwest oriented seismicity depth profiles show the existence of a Benioff zone dipping to the southeast beneath northwestern Venezuela and northern Colombia. This indicates the presence of a northeast striking, southeast dipping subducted slab of the Caribbean plate beneath the South American plate. Hypocentral locations show that the northeastern end of this subduction occurs northwest of the Curaçao-Aruba region, in the vicinity of a northwest trending, right-lateral strike-slip fault zone that joins up with the northeastern end of the Boconó fault zone. This latter place turns out to be the western end of the east-west striking San Sebastián fault along the Venezuelan coast.

PéRez, Omar J.; Jaimes, Martha A.; Garciacaro, Emilio

1997-08-01

232

Residential energy use and conservation in Venezuela: Results and implications of a household survey in Caracas  

SciTech Connect

This document presents the final report of a study of residential energy use in Caracas, the capital of Venezuela. It contains the findings of a household energy-use survey held in Caracas in 1988 and examines options for introducing energy conservation measures in the Venezuelan residential sector. Oil exports form the backbone of the Venezuelan economy. Improving energy efficiency in Venezuela will help free domestic oil resources that can be sold to the rest of the world. Energy conservation will also contribute to a faster recovery of the economy by reducing the need for major investments in new energy facilities, allowing the Venezuelan government to direct its financial investments towards other areas of development. Local environmental benefits will constitute an important additional by-product of implementing energy-efficiency policies in Venezuela. Caracas`s residential sector shows great potential for energy conservation. The sector is characterized by high saturation levels of major appliances, inefficiency of appliances available in the market, and by careless patterns of energy use. Household energy use per capita average 6.5 GJ/per year which is higher than most cities in developing countries; most of this energy is used for cooking. Electricity accounts for 41% of all energy use, while LPG and natural gas constitute the remainder. Specific options for inducing energy conservation and energy efficiency in Caracas`s residential sector include energy-pricing policies, fuel switching, particularly from electricity to gas, improving the energy performance of new appliances and customer information. To ensure the accomplishment of an energy-efficiency strategy, a concerted effort by energy users, manufacturers, utility companies, government agencies, and research institutions will be needed.

Figueroa, M.J.; Ketoff, A.; Masera, O.

1992-10-01

233

Sentinel Surveillance of Influenza-Like Illness in Two Hospitals in Maracay, Venezuela: 2006–2010  

PubMed Central

Background Limited information exists on the epidemiology of acute febrile respiratory illnesses in tropical South American countries such as Venezuela. The objective of the present study was to examine the epidemiology of influenza-like illness (ILI) in two hospitals in Maracay, Venezuela. Methodology/Principal Findings We performed a prospective surveillance study of persons with ILI who presented for care at two hospitals in Maracay, Venezuela, from October 2006 to December 2010. A respiratory specimen and clinical information were obtained from each participant. Viral isolation and identification with immunofluorescent antibodies and molecular methods were employed to detect respiratory viruses such as adenovirus, influenza A and B, parainfluenza, and respiratory sincytial virus, among others. There were 916 participants in the study (median age: 17 years; range: 1 month – 86 years). Viruses were identified in 143 (15.6%) subjects, and one participant was found to have a co-infection with more than one virus. Influenza viruses, including pandemic H1N1 2009, were the most frequently detected pathogens, accounting for 67.4% (97/144) of the viruses detected. Adenovirus (15/144), parainfluenza virus (13/144), and respiratory syncytial virus (11/144) were also important causes of ILI in this study. Pandemic H1N1 2009 virus became the most commonly isolated influenza virus during its initial appearance in 2009. Two waves of the pandemic were observed: the first which peaked in August 2009 and the second - higher than the preceding - that peaked in October 2009. In 2010, influenza A/H3N2 re-emerged as the most predominant respiratory virus detected. Conclusions/Significance Influenza viruses were the most commonly detected viral organisms among patients with acute febrile respiratory illnesses presenting at two hospitals in Maracay, Venezuela. Pandemic H1N1 2009 influenza virus did not completely replace other circulating influenza viruses during its initial appearance in 2009. Seasonal influenza A/H3N2 was the most common influenza virus in the post-pandemic phase. PMID:22984519

Comach, Guillermo; Teneza-Mora, Nimfa; Kochel, Tadeusz J.; Espino, Carlos; Sierra, Gloria; Camacho, Daria E.; Laguna-Torres, V. Alberto; Garcia, Josefina; Chauca, Gloria; Gamero, Maria E.; Sovero, Merly; Bordones, Slave; Villalobos, Iris; Melchor, Angel; Halsey, Eric S.

2012-01-01

234

Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela  

USGS Publications Warehouse

The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 42 species of diurnal raptors observed in affected areas in this region. We observed some raptors considered as forest interior species and other open country species foraging and roosting in man-made openings inside the forest.

Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.

1996-01-01

235

Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela  

USGS Publications Warehouse

The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 40 species of diurnal raptors observed in ten affected areas, including raptors considered as forest interior species and some open country species utilizing the man-made openings inside the forest for roosting and foraging.

Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.

1994-01-01

236

Resumen. La fosa de Cariaco, ubicada al sur del Caribe en el margen continental de Venezuela, ha sido el foco de muchos estudios de relevancia global sobre la qumica de las aguas marinas y la  

E-print Network

Resumen. La fosa de Cariaco, ubicada al sur del Caribe en el margen continental de Venezuela, ha ("2004"), 161-162: 215-234 #12;216 Características de la fosa de Cariaco, Venezuela Cariaco basin on the continental margin of Venezuela, has been the focus of many marine chemistry and paleoclimatology studies

Meyers, Steven D.

237

FRONTISPIECE. Three-striped Warblers (Basileuterus tristriatus) were studied in the northern Andes of Venezuela. Temperate and tropical parulids differ strongly in life histories. Three-striped Warblers have smaller clutches, longer  

E-print Network

of Venezuela. Temperate and tropical parulids differ strongly in life histories. Three-striped Warblers have(4):667­678, 2009 BREEDING BIOLOGY OF THE THREE-STRIPED WARBLER IN VENEZUELA: A CONTRAST BETWEEN TROPICAL traits of the Three-striped Warbler (Basileuterus tristriatus) from 146 nests in Venezuela and compare

Martin, Thomas E.

238

Paleogeographic evolution of foldbelts adjacent to petroleum basins of Venezuela and Trinidad  

SciTech Connect

The foldbelts of Venezuela and Trinidad have shaped the history of adjacent sedimentary basins. A set of paleogeographic maps on reconstructed bases depict the role of foldbelts in the development of the sedimentary basins of Venezuela. Some of the foldbelts are inverted, pre-Tertiary graben/passive margin systems. Other foldbelts are allochthonous nappes or parautochthons that override the Mesozoic passive margin hinge without inversion. The emergence of these foldbelts changed the course of existing river systems and provided a new source for sediments and maturation in adjacent deeps. The Merida Andes area was remobilized beginning in the Early Miocene as a zone of lateral shear, along which the Bonaire Block has moved over 200 km to the northeast, dismembering the Maracaibo and Barinas basins. Late Miocene to Recent transpression and fault reactivation have driven rapid Andean uplift with thrust-related subsidence and maturation (e.g., SE Maracaibo foredeep). To the east, uplift and erosion of the Serrania del Interior (1) curtailed mid-Tertiary fluvial systems flowing northward from the igneous and sedimentary rocks of the Guyana Shield, deflecting them eastward, and (2) removed the thick early Miocene foredeep fill into a younger foredeep. Thus, the fold-thrust belts and sedimentary basins in this region are linked in their evolutionary histories.

Goodman, E.D.; Koch, P.S.; Summa, L.L. [Exxon Production Research Company, Houston, TX (United States)] [and others

1996-08-01

239

Comparison of the petroleum systems of East Venezuela in their tectonostratigraphic context  

SciTech Connect

The Maturin and Guarico subbasins of East Venezuela record the transition from Cretaceous passive margin to Tertiary foreland basin with local post-orogenic transtensional basins. Petroleum is reservoired in several units ranging from Albian (El Cantil Formation) to Pliocene (Las Piedras Formation) age. Source rocks are principally in the Upper Cretaceous (Querecual Formation), and Miocene (Carapita Formation) in the Maturin subbasin and in the Upper Cretaceous (Tigre Formation) and Oligocene (Roblecito and La Pascua Formations) in the Guarico subbasin. An extensive well database has been used to address the distribution and provenance of hydrocarbons in the context of a tectonostratigraphic model for the evolution of the East Venezuela basin. Nine major plays have been described, comprising thirteen petroleum systems. The principal factors influencing the components of individual petroleum systems are as follows: (1) structural controls on Upper Cretaceous source rock distribution, relating to block faulting on the proto-Caribbean passive margin; (2) paleoenvironmental controls on source rock development within the Oligocene-Miocene foreland basin; and (3) timing of subsidence and maturation within the Oligocene-Upper Miocene foreland basin and the configuration of the associated fold and thrust belt, influencing long range and local migration routes (4) local development of Pliocene post-orogenic transtensional basins, influencing hydrocarbon generation, migration and remigration north of the Pirital High.

Stronach, N.J.; Kerr, H.M.; Scotchmer, J. [Robertson Research International Ltd., Llandudno, Gwynedd (United Kingdom); Hunter, V. [Consultores Geostrat CA, Puerto La Cruz (Venezuela)

1996-08-01

240

An Estimate of Recoverable Heavy Oil Resources of the Orinoco Oil Belt, Venezuela  

USGS Publications Warehouse

The Orinoco Oil Belt Assessment Unit of the La Luna-Quercual Total Petroleum System encompasses approximately 50,000 km2 of the East Venezuela Basin Province that is underlain by more than 1 trillion barrels of heavy oil-in-place. As part of a program directed at estimating the technically recoverable oil and gas resources of priority petroleum basins worldwide, the U.S. Geological Survey estimated the recoverable oil resources of the Orinoco Oil Belt Assessment Unit. This estimate relied mainly on published geologic and engineering data for reservoirs (net oil-saturated sandstone thickness and extent), petrophysical properties (porosity, water saturation, and formation volume factors), recovery factors determined by pilot projects, and estimates of volumes of oil-in-place. The U.S. Geological Survey estimated a mean volume of 513 billion barrels of technically recoverable heavy oil in the Orinoco Oil Belt Assessment Unit of the East Venezuela Basin Province; the range is 380 to 652 billion barrels. The Orinoco Oil Belt Assessment Unit thus contains one of the largest recoverable oil accumulations in the world.

Schenk, Christopher J.; Cook, Troy A.; Charpentier, Ronald R.; Pollastro, Richard M.; Klett, Timothy R.; Tennyson, Marilyn E.; Kirschbaum, Mark A.; Brownfield, Michael E.; Pitman, Janet K.

2009-01-01

241

Are Returns to Education on the Decline in Venezuela and Does Mission Sucre Have a Role to Play?  

ERIC Educational Resources Information Center

Anecdotal evidence points to a falling standard of living for the educated in Venezuela. During this same period, President Hugo Chavez implemented several education reforms. We focus on a major university education reform known as Mission Sucre and its potential impact on returns to university education. First, we show that returns to education…

Gonzalez, Naihobe; Oyelere, Ruth Uwaifo

2011-01-01

242

Identification of factors affecting growth and survival of the tropical scallop Euvola (Pecten) ziczac in the Golfo de Cariaco, Venezuela  

Microsoft Academic Search

We examined the effect of environmental variables on the growth and survival of the tropical scallop, Euvola ziczac (L.), in suspended culture at Turpialito in the Golfo de Cariaco, northeastern Venezuela. Four growth trials were run, three using 10-mm spat produced from hatchery spawnings in August 1992, which were grown at 8, 21 and 34 m in depth, and a

César J. M Lodeiros; John H Himmelman

2000-01-01

243

Molecular epidemiology of dengue type 2 virus in Venezuela: evidence for in situ virus evolution and recombination  

Microsoft Academic Search

Epidemic outbreaks of dengue fever (DF) were first recorded in Venezuela in 1978 and were followed by the emergence of dengue haemorrhagic fever (DHF) outbreaks in 1989. To gain a better understanding of the nature of these epidemics, the complete envelope (E) gene sequence of 34 Venezuelan dengue type 2 (DEN-2) viruses, isolated between 1997 and 2000 was determined. Of

N. Y. Uzcategui; D. Camacho; G. Comach; R. Cuello de Uzcategui; E. C. Holmes; E. A. Gould

2001-01-01

244

Preliminary assessment of a Cretaceous-Paleogene Atlantic passive margin, Serrania del Interior and Central Ranges, Venezuela/Trinidad  

SciTech Connect

For several decades, Cretaceous arc collision was assumed along northern Venezuela based on isotopic ages of metamorphic minerals. From subsidence histories in Venezuelan/Trinidadian basins, however, it is now clear that the Cretaceous metamorphic rocks were emplaced southeastward as allochthons above an autochthonous suite of rocks in the Cenozoic, and that the pre-Cenozoic autochthonous rocks represent a Mesozoic passive margin. The passive margin rocks have been metamorphosed separately during overthrusting by the allochthons in central Venezuela, but they are uplifted but not significantly metamorphosed in Eastern Venezuela and Trinidad. There, in the Serrania del Interior and Central Ranges of Venezuela/Trinidad, Mesozoic-Paleogene passive margin sequences were uplifted in Neogene time, when the Caribbean Plate arrived from the west and transpressionally inverted the passive margin. Thus, this portion of South America's Atlantic margin subsided thermally without tectonism from Jurassic to Eocene time, and these sections comprise the only Mesozoic-Cenozoic truly passive Atlantic margin in the Western Hemisphere that is now exposed for direct study. Direct assessments of sedimentological, depositional and faunal features indicative of, and changes in, water depth for Cretaceous and Paleogene time may be made here relative to a thermally subsiding passive margin without the complications of tectonism. Work is underway, and preliminary assessments presented here suggest that sea level changes of Cretaceous-Paleogene time are not as pronounced as the frequent large and rapid sea level falls and rises that are promoted by some.

Pindell, J.L.; Drake, C.L. (Dartmouth College, Hanover, NH (United States)); Pitman, W.C. (Lamont-Doherty Geological Observatory, Palisades, NY (United States))

1991-03-01

245

Two new Fusicoccum species from Acacia and Eucalyptus in Venezuela, based on morphology and DNA sequence data  

E-print Network

Two new Fusicoccum species from Acacia and Eucalyptus in Venezuela, based on morphology and DNA of woody plants, and they also include some serious pathogens of Eucalyptus and Acacia species. Numerous common. Here, we characterize two new Fusicoccum species, isolated from Eucalyptus and Acacia trees

246

Seismic Anisotropy and Mantle flow beneath Western Venezuela Jeniffer Masy,1 Fenglin Niu1 and Alan Levander1  

E-print Network

fault, where splitting times are the largest (1.6 - 2.5 s) with an east-west orientation. The second of Venezuela and the Antilles arc Region). At each station, SKS waveforms from 2 to 60 earthquakes, mostly from Fault, OAF = Oca- Ancon Fault. Figure 2: A) SKS waveform recorded on the radial (top) and transverse

Alvarez, Pedro J.

247

Conservation science in developing countries: an inside perspective on the struggles in sea turtle research and conservation in Venezuela  

Microsoft Academic Search

Human exploitation of sea turtles in Venezuela dates back at least 800 years and continues to the present day. The first concerns about the status of sea turtle populations arose in the 1970s, and the projects from this early era were a tagging program, beach evaluation and in situ nest protection. Since then, efforts to develop a sea turtle research

Joaquín Buitrago; Hedelvy J. Guada; Emma Doyle

2008-01-01

248

Biocomplexity of deforestation in the Caparo tropical forest reserve in Venezuela: An integrated multi-agent and cellular automata model  

Microsoft Academic Search

A multi-agent model of social and environmental complexity of deforestation was developed for the Caparo Forest Reserve, Venezuela. It includes three types of agents: settlers, government, and lumber concessionaires. Settlers represent people of limited economic resources that deforest and occupy reserve land to grow crops and eventually claim property rights of this land. Their agricultural practices generate unintended environmental problems.

Niandry Moreno; Raquel Quintero; Magdiel Ablan; Rodrigo Barros; Jacinto A. Dávila; Hirma Ramírez; Giorgio Tonella; Miguel F. Acevedo

2007-01-01

249

Stochastic modeling of lower delta and coastal plain reservoir in the Eocene-Misoa Formation, Ceuta Field, Venezuela  

Microsoft Academic Search

Stochastic modeling technique minimizes uncertainties in the values used for reservoir parameters and this reduces the risk in reservoir management practices. This technique was successfully employed in modeling south Ceuta field in Venezuela which will be subjected to secondary recovery due to significant pressure decline. The Lower Misoa reservoir is divided into five sedimentological units; the upper three units am

I. Azpiritxaga; E. Hernandez; M. Vivas

1995-01-01

250

Situation Report--Burma, Chile, German Democratic Republic, Indonesia, Jamaica, Poland, Singapore, St. Christopher/Nevis, Trinidad & Tobago, Venezuela.  

ERIC Educational Resources Information Center

Data relating to population and family planning in ten foreign countries are presented in these situation reports. Countries included are Burma, Chile, German Democratic Republic, Indonesia, Jamaica, Poland, Singapore, St. Christopher/Nevis, Trinidad and Tobago, and Venezuela. Information is provided, where appropriate and available, under two…

International Planned Parenthood Federation, London (England).

251

Contribution of Subduction Dynamic Topography to the Formation of the Maturin Foreland Basin Eastern Venezuela  

NASA Astrophysics Data System (ADS)

The Maturín Basin in Eastern Venezuela, which formed during the Neogene adjacent to the Serranía del Interior Thrust Belt, is considered a good example of a peripheral foreland basin. Earthquake and tomographic data indicate that Eastern Venezuela is underthrust by the oblique subduction of the South American Plate underneath the Caribbean Plate. Our objectives are to understand the processes responsible for the formation of the Maturin Basin, and to quantitatively determine the contribution of thrust sheet loading and continental subduction. A sequence of new forward flexural isostatic models was generated from Middle Miocene to Present for 3 profiles across the Serranía del Interior Thrust Belt and Maturín Foreland Basin in order to determine the contribution of thrust sheet loading to foreland basin subsidence. The predictions of these models are constrained using seismic reflection and well data. The flexural isostatic modelling shows that thrust-sheet loading associated with the Serranía del Interior Thrust Belt is insufficient to generate the observed subsidence within the Maturín Basin. The modelled basin depth is shallower than observed by 2 km in the west and 6 km in the east. A topography and basin mass balance study, and comparison with free air gravity anomalies for other foreland basin and mountain belt systems, confirms that the mass deficiency in the Monagas Basin is too large to be regionally compensated by the mass excess in the Serranía Thrust Belt. Dynamic fluid flow modelling of subduction related dynamic topography of Eastern Venezuela has been used to investigate the influence of South American subduction on the generation of the accommodation space observed in the Maturín Basin. Fluid flow modelling of subduction related dynamic topography suggests that the subduction of the South American lithospheric mantle caused downward deflection of the South American crust affecting the Maturín Basin and the Serranía Thrust Belt. This result is consistent with earthquake and tomographic evidence. The total subsidence predicted using preferred thrust sheet loading and fluid flow models is comparable with the wavelength and amplitude of the subsidence observed in the eastern part of the Maturín Basin. This modelling suggests that the Maturín Basin subsidence has two components: 55% in amplitude related to thrust sheet loading and 45% driven by continental subduction. The subduction-related subsidence is greater in the eastern than in the western parts of the basin, consistent with the South American subduction decreasing to the west.

Jacome, M.; Kusznir, N.; Audemard, F.; Flint, S.

2001-12-01

252

Methane production from mixed tropical savanna and forest vegetation in Venezuela  

NASA Astrophysics Data System (ADS)

Measurements of methane concentrations in the boundary layer in the northern part of the Guayana shield, Venezuela, during the wet season (October 1988), showed the presence of substantial methane surface emissions. The measuring site is within the savanna climate region, but is affected by emissions from savanna and forest vegetation. From day versus night concentration measurements, with higher concentrations during night, a methane source strength near the site of 3-7×1011 molecules/cm2/s can be estimated, which includes emissions from small tracts of flooded soils, termites and especially tropical vegetation. Extrapolated to the entire savanna, this may imply a methane source of ~30-60 Tg yr-1 similar to the one calculated for tropical vegetation on the basis of recently published in vitro plant emission experiments by Keppler et al. (2006), which indicate emissions of ~30 Tg yr-1 for tropical savannas and grasslands and ~78 Tg yr-1 for tropical forests.

Crutzen, P. J.; Sanhueza, E.; Brenninkmeijer, C. A. M.

2006-04-01

253

CTX-M-14 ?-lactamase-producing Citrobacter freundii isolated in Venezuela  

PubMed Central

A clinical isolate of C. freundii with reduced susceptibility to extended-spectrum ?-lactams from a woman with cystocele associated with recurrent urinary tract infection was analyzed. Susceptibility tests, double disk synergy tests (DDST) and enzymatic activity by the agar iodometric method suggested the presence of ESBLs. Conjugation experiments revealed the presence of a large conjugative plasmid (pLM07/20) with an exclusive FrepB replicon type (IncF/FIB). PCR analysis and sequencing confirmed the presence of the blaCTX-M-14 gene in the pLM07/20 from C. freundii.LM07/10. Although this is the first report of CTX-M-14 in Venezuela, we alert the medical community that future increase of these ?-lactamases in our city could be due to dissemination of plasmids into bacterial populations. PMID:21627834

2011-01-01

254

AVO in North of Paria, Venezuela: Gas methane versus condensate reservoirs  

SciTech Connect

The gas fields of North of Paria, offshore eastern Venezuela, present a unique opportunity for amplitude variations with offset (AVO) characterization of reservoirs containing different fluids: gas-condensate, gas (methane) and water (brine). AVO studies for two of the wells in the area, one with gas-condensate and the other with gas (methane) saturated reservoirs, show interesting results. Water sands and a fluid contact (condensate-water) are present in one of these wells, thus providing a control point on brine-saturated properties. The reservoirs in the second well consist of sands highly saturated with methane. Clear differences in AVO response exist between hydrocarbon-saturated reservoirs and those containing brine. However, it is also interesting that subtle but noticeable differences can be interpreted between condensate-and methane-saturated sands. These differences are attributed to differences in both in-situ fluid density and compressibility, and rock frame properties.

Regueiro, J. [Univ. Simon Bolivar, Sartenejas (Venezuela)] [Univ. Simon Bolivar, Sartenejas (Venezuela); Pena, A. [Lagoven S.A., Caracas (Venezuela)] [Lagoven S.A., Caracas (Venezuela)

1996-07-01

255

GPS-derived slip rates of active faults in eastern Venezuela, along the southeastern Caribbean PBZ  

NASA Astrophysics Data System (ADS)

For over 20 years, GPS campaign measurements have been performed in eastern Venezuela, as well as in other areas of the country, by different scientific groups and in the frame of different either national or international efforts and/or projects, essentially aiming at the estimation of the rate of motion along the major Quaternary faults (i.e., Boconó, San Sebastián and El Pilar faults) composing the plate boundary zone (PBZ) between the Caribbean and South America, along onshore northern and western Venezuela. The slip rates and sense of slip of those major faults derived from the comparison of several GPS campaigns carried out through the years have confirmed the slip data (fault kinematics) previously derived from geologic data, through comprehensive neotectonic and paleoseismic studies mainly made by the FUNVISIS' Earth Sciences Dpt. staff. In a rough way, we could conclude that those faults are dextrally moving at a rate in the order of 10-12 mm/a. More recently, it has been shown that the El Pilar fault has a locking depth close to 10 km deep and that about half of the PBZ dextral motion is accommodated as creep, reducing the seismic hazard for northeastern Venezuela almost by half. On the contrary, in the near past, very little attention has been paid to the secondary active faulting in eastern Venezuela. In that sense, FUNVISIS, in collaboration with the Université de Savoie, started the monitoring of these secondary features by installing 36 brass benchmarks on bedrock in that region in 2003, which have been occupied 3 times, in late 2003 and 2005 and in early 2013. The comparison between the 2003 and 2005 occupations shows promising results, such as: a) The Charagato fault on Cubagua island is left-lateral with a slip rate of about 2 mm/a; b) slip vectors across the El Pilar fault tend to head to the ESE, suggesting that the tectonic regime is compressive transcurrent to transcurrent compressional (transpressional); c) The NW-SE-trending San Francisco fault, in the eastern Interior range, appears to be dextral with a preliminary slip rate of few mm/a; d) the Northern Coast fault, paralleling the El Pilar fault, is also dextral and slips at about 2 mm/a and e) a similar situation seems to display the San Sebastián fault in the Gulf of Cariaco, north of Cumaná, near its eastern tip. We expect that the 2013 occupation, carried out over 9 years later than the first one, will allow estimating more accurately the slip rates of the slower subordinate active faults of the region. This is a contribution to cooperation projects FONACIT-ECOS Nord PI-2003000090 and -2009000818 (French codes V04U01 and V10U01, respectively), French DyETI Programme, as well as Venezuelan FONACIT 2002000478 (GEODINOS) and LOCTI (Cumaná and GIAME) projects. Michel Bechtold, Victor Cano, Luis Melo, Reinaldo Ollarves, Fabián Rada, José Antonio Rodríguez, Javier Sánchez and Aurelien Van Welden are contributing FEGAG members.

Audemard, F. A.; Beck, C.; Jouanne, F.; Reinoza, C. E.; Fegag

2013-05-01

256

Management of a giant deep field: El Furrial Field, Eastern Venezuela  

SciTech Connect

The Furrial Field is located in Eastern Venezuela and produces a 25 to 30{degrees} API asphaltenic crude oil from a 1500 ft thick Oligocene sand interval at a depth of 15,000 ft. The bubble point is about 4500 psi as compared to an original pressure of 11,000 psi. Oil in place is approximately 6800 million STB. Currently production is 350 MB/D from 77 well streams (Naricual Formation), and water is being injected at 400 MB/D to maintain pressure. The combination of a volumetric reservoir and asphaltenic nature of crude oil resulted in a rapid decrease in well productivity and reservoir pressure, creating the necessity to maintain reservoir pressure to maximize recovery. Discussed in this paper are the reservoir management techniques and strategies used by Lagoven to develop and operate these complex reservoirs. Acquisition and analysis of these data adequate to properly implement these management techniques are covered in detail.

Pinto, N.; Mengual, R.; Anz, J.; Rodney, C. [Lagoven, S.A., Maturin (Venezuela)

1996-08-01

257

Methodology to incorporate EIA in land-use ordering -- case study: The Cataniapo River basin, Venezuela  

SciTech Connect

In Venezuela, the idea of tiering information between land-use ordering instruments and impact assessment is absent. In this article the authors explore a methodological alternative to bridge the information presented in land-use ordering instruments with the information requirements for impact assessment. The methodology is based on the steps carried out for an environmental impact assessment as well as on those considered to develop land-use ordering instruments. The methodology is applied to the territorial ordering plan and its proposal for the protection zone of the Cataniapo River basin. The purpose of the protection zone is to preserve the water quality and quantity of the river basin for human consumption.

Sebastiani, M.; Llambi, L.D.; Marquez, E. [Univ. Simon Bolivar (Venezuela)] [and others] [Univ. Simon Bolivar (Venezuela); and others

1998-07-01

258

Reliability as the big persuader to privatize the electrical system in Venezuela  

SciTech Connect

Throughout the past five years, the Venezuelan authorities, especially the Fondo de Inversiones de Venezuela (FIV), have done a major effort to privatize many of the state owned industries, among them, the electrical public utilities and some important electrical power generation plants or systems based on thermal generation. Mainly along the recent past years, black and brownouts have become more frequent in the system. In other words, system reliability has been diminishing, as a consequence of investment capital and O and M expenses have been reduced to levels below the required by the system. Public opinion is exercising pressure on politicians, so signals are that Congress will probably approve during the current or beginning of next years the required laws to expedite privatization and assure incentives and guaranties to investors. This paper deals with the insides of all these aspects, and with how soon privatization will be carried out. The FIV has been committed to implement this process.

Alvarez B., C.E. [Tecnoconsult/Tecnofluor, Caracas (Venezuela). Power Div.

1998-12-31

259

Applied geointegration to hydrocarbon exploration in the San Pedro-Machango Area, Maracaibo Basin, Venezuela  

SciTech Connect

Hydrocarbon exploration has nowadays a diversity of technological resources to capture, merge and interpret information from diverse sources. To accomplish this, the integration of geodata for modeling was done through the use of new technologies like Remote Sensing and Geographical Systems of Information and applied to the San Pedro-Machango area, located in the Serrania de Trujillo, west of Costa Bolivar (onshore), eastern Maracaibo Basin, Venezuela. The main purpose of this work was to optimize the design of an exploration program in harmony with environmental conservation procedures. Starting with satellital and radar images that incorporated geophysical, geological and environmental information, they then were analyzed and merged to improve the lithological, structural and tectonic interpretation, generating an integrated model that allowed better project design. The use of a system that combines information of geographical, geodetical, geophysical and geological origins with satellital and radar images produced up to date cartography and refined results of image interpretation.

Fonseca, A.; Navarro, A. [Maraven, S.A., Caracas (Venezuela); Osorio, R.; Corvo, F.; Arismendi, J. [Instituto de Ingenieria, Caracas (Venezuela)

1996-08-01

260

Genetic diversity between and within the arenavirus species indigenous to western Venezuela  

PubMed Central

The results of analyses of Z, RNA-dependent RNA polymerase, glycoprotein precursor, and nucleocapsid protein gene sequence data suggested that Guanarito virus was the most common cause of Venezuelan hemorrhagic fever in a 7-year period in the 1990’s and that the evolution of Pirital virus in association with Sigmodon alstoni (Alston’s cotton rat) has occurred at a significantly higher rate than the evolution of Guanarito virus in association with Zygodontomys brevicauda (short-tailed cane mouse) on the plains of western Venezuela. The results of analyses of the primary structures of the glycoproteins of the 8 strains of Guanarito virus isolated from humans suggested that these strains would be highly cross-reactive in neutralization assays. Thus, passive antibody therapy may prove beneficial in the treatment of human disease caused by strains of Guanarito virus that are enzootic in the region in which Venezuelan hemorrhagic fever is endemic. PMID:18586298

Fulhorst, Charles F.; Cajimat, Maria N.B.; Milazzo, Mary Louise; Paredes, Hector; de Manzione, Nuris M. C.; Salas, Rosa A.; Rollin, Pierre E.; Ksiazek, Thomas G.

2008-01-01

261

Cretaceous and Tertiary palynology used in the geological understanding of the Maturin sub-basin, Venezuela  

SciTech Connect

The use of palynology and micropaleontology, two biostratigraphic tools used at Intevep, S.A., have been of great help in the geological understanding during studies done on cores of the Maturin subbasin, a foreland type basin in Eastern Venezuela. Basically, the palynological work consisted of palynological and palynofacies analysis used to determine ages and to interpret the paleoenvironments of deposition in comparison with the interpretations obtained through sedimentological and micropaleontological studies. Palynomorph assemblages and palynofacies are shown for the quiescent Late Cretaceous, for the Tertiary in sequences that are not exactly dated and probably represent the first compressive movements in the basin, and for the Oligocene. In general, in these sequences it was possible to determine marine environments varying from near-shore to inner neritic, and also subaereal paleosols in the Cretaceous. The work highlights the importance of multidisciplinary studies in order to obtain interpretations more in accordance with reality.

Paredes, I.; Fasola, A. (Intevep, S.A., Caracas (Venezuela))

1991-03-01

262

Sedimentological characterization of the C2' sequence, Block Lamar field, Maracaibo basin, Venezuela  

SciTech Connect

Through the study of 2,109 ft of core from the Block V-Lamar field, central Maracaibo basin, Venezuela, the environments of deposition were established. The studied interval corresponds to the informal C2 sands of the Misoa Formation (Eocene). Seven different lithofacies were identified and later grouped into three sedimentary units deposited in a general, fluvial-dominated deltaic environment. The organization of the different lithofacies along with palynological data permitted the assignment of lower delta plain, upper delta plain, and, again, lower delta plain for the sedimentary units. The main subenvironments encountered include amalgamated distributary channel bars and related interdistributary bays. The distributary channels are thicker in the upper delta plain unit owing to a higher degree of stacking. Furthermore, sandstone thickness decreases in a southwest-northwest sense which indicates the direction of regression. This can be documented also with petrophysical characteristics of the reservoir reflected as a continuous decrease in porosity from 25 to 18%.

Gustavo, F.B.; Gonzales, C. (INTEVEP, S.A., Caracas (Venezuela))

1991-03-01

263

Training Hybrid Neuro-Fuzzy System to Infer Permeability in Wells on Maracaibo Lake, Venezuela  

E-print Network

The high accuracy on inferrring of rocks properties, such as permeability ($k$), is a very useful study in the analysis of wells. This has led to development and use of empirical equations like Tixier, Timur, among others. In order to improve the inference of permeability we used a hybrid Neuro-Fuzzy System (NFS). The NFS allowed us to infer permeability of well, from data of porosity ($\\phi$) and water saturation ($Sw$). The work was performed with data from wells VCL-1021 (P21) and VCL-950 (P50), Block III, Maracaibo Lake, Venezuela. We evaluated the NFS equations ($k_{P50,i}(\\phi_i,Sw_i)$) with neighboring well data ($P21$), in order to verify the validity of the equations in the area. We have used ANFIS in MatLab.

Hurtado, Nuri; Torres, Julio

2014-01-01

264

First report of metallo-?-lactamases producing Enterobacter spp. strains from Venezuela.  

PubMed

Clinical strains of Enterobacter were isolated from Cumana's Central Hospital in Venezuela, and classified as E. cloacae (21), E. aerogenes (7), E. intermedium (1), E. sakazakii (1) and three unclassified. The strains showed high levels of resistance, especially to SXT (58.1%), CRO (48.8%), CAZ (46.6%), PIP (46.4%), CIP (45.2%) and ATM (43.3%). This is the first report for South America of blaVIM-2 in two E. cloacae and one Enterobacter sp., which also showed multiple mechanisms of resistance. Both E. cloacae showed blaTEM-1, but only one showed blaCTX-M-15 gene, while no blaSHV was detected. PMID:24553611

Martínez, Dianny; Rodulfo, Hectorina E; Rodríguez, Lucy; Caña, Luisa E; Medina, Belkis; Guzman, Militza; Carreño, Numirin; Marcano, Daniel; De Donato, Marcos

2014-01-01

265

Trypanosoma cruzi, the Causal Agent of Chagas Disease: Boundaries between Wild and Domestic Cycles in Venezuela  

PubMed Central

Trypanosoma cruzi the etiological agent of American Trypanosomiasis or Chagas disease (ChD) is transmitted by triatomines vectors between mammals including man. T. cruzi has existed for circa 150?Ma in the Americas and nearly 10 million people are currently infected. The overlap between wild and domestic ecotopes where T. cruzi circulates is increasing. Host–parasite interactions have been determined by infection patterns in these cycles, all under natural or laboratorial conditions. This mini-review describes specific parasite niches, such as plant communities or biological corridors between domestic and wild landscapes, in order to help identify risk factors for ChD and define the boundaries between wild and domestic transmission cycles, with an emphasis on research undertaken in Venezuela. PMID:25506587

Herrera, Leidi

2014-01-01

266

[Superficial mycoses in patients from Anzoátegui state, Venezuela, period 2002-2012].  

PubMed

Superficial fungal diseases that affect the skin and its appendages are frequently seen in basic triage and in dermatology services. These diseases are distributed in Venezuela with an incidence of 92.9%. The aim of this study was to determine the genera and species that cause dermatomycoses in residents of Anzoátegui state, Venezuela, during the period 2002-2012. A total of 4257 patients with a presumptive diagnosis of superficial mycoses were studied, with ages from 7 months to 79 years. The overall prevalence was 30.9%. The most frequent were dermatophytosis (44.7%). M. canis produced 148 cases of tinea capitis. Three dermatophytic agents represented 95% of all cases, with a significant predominance of T. mentagrophytes with 50%. Candidosis occurred in 28.4%. C. albicans, and the C. parapsilosis complex, were responsible for 80% of the cases. The other species identified were C. tropicalis (n = 41, 11.0%), C. glabrata (n = 10, 2.7%), C. guilliermondii (n = 6, 1.6%), C. krusei (n = 4, 1.1%). Pityriasis versicolor occurred in 22.4% of the cases studied, and less frequently were present onychomycosis produced by a non dermatophytic mold: Fusarium oxysporum (n = 34, 65.4%), Aspergillus terreus (n=16, 30.8%) and Scytalidium dimidiatum (n=2; 3.8%). Rare cases of Trichosporon onychomycosis (0.5%) and one case of black tinea were also found. Health education in the population is recommended to promote measures to prevent transmission of these fungi and prevent the spread of this silent public health problem. PMID:25558751

Lemus-Espinoza, Druvic; Teresa Maniscalchi, María; Villarroel, Oskarina; Bónoli, Stefano B; Wahab, Fadi; García, Oswaldo

2014-12-01

267

Venezuela offshore oil and gas production development: Past, present and future  

SciTech Connect

This paper presents a short history of offshore oil and gas production in Venezuela starting in Lake Maracaibo in 1923. The main emphasis has been the results of the recent R and D and the exploratory offshore programs in areas like Orinoco Delta located in the Atlantic Ocean, Northeast and Northwest Venezuela in the Caribbean sea. In the R and D offshore program the main objectives were: (1) To establish the local environmental, oceanographical, geotechnical and seismicity conditions for the Venezuelan Continental Platform. (2) To give a technical support to the PDVSA Operating Affiliates during the exploratory programs including: (a) to develop accurate drilling vessel positioning systems; (b) evaluation of sea bottom geotechnical conditions for safely operating the jack-ups and drilling vessels involved in the exploratory wells and (c) to identify those areas which because of their special nature require further investigation to establish preliminary type of platforms required for the areas to be developed or to evaluate other solutions proposed by Foreign Consultant Engineering Companies to the PDVSA Operating Affiliated Companies. The main objective of PDVSA for the coming future will be to develop the North of Paria Gas Field through the initially named Christopher Columbus Project now Sucre Gas, S.A., a consortium conformed by LaGoven, S.A. Shell, Exxon and Mitsubishi. objective of this paper is to give an idea of the history of the Venezuelan Oil and Gas Offshore development giving emphasis to the results of the INTEVEP S.A. Red offshore program and to show some results of the particular characteristics of oceanographical, environmental, geotechnical and seismic conditions in the main areas evaluated during the exploratory program: Orinoco Delta, Gulf of Paria and North of Paria.

Perez La Salvia, H.; Schwartz, E.; Contreras, M.; Rodriguez, J.I.; Febres, G.; Gajardo, E.

1995-12-01

268

Integrated foraminiferal biostratigraphy and chemostratigraphy of the querecual formation (Cretaceous), Eastern Venezuela  

USGS Publications Warehouse

An integrated foraminiferal biostratigraphy and chemostratigraphy is presented for the Lower to Upper Cretaceous Querecual Formation exposed on Chimana Grande Island, Eastern Venezuela. The formation consists of >450 m alternating foraminiferal and organic-rich carbonates and laminated mudrocks, and is considered the main hydrocarbon source rock for the eastern Venezuela Basin. Biostratigraphic resolution within the Querecual Formation is poor, due to a paucity of keeled planktonic foraminifera and impoverished benthic faunas. Deposition occurred in a bathyal environment, with dysaerobic or anoxic bottom waters resulting from high rates of surface productivity associated with an upwelling environment. Biostratigraphic evidence indicates that the Querecual Formation ranges from the upper Albian Rotalipora ticinensis Zone to the Santonian Dicarinella asymetrica Zone. Iron and Al contents fall through the Albian-Cenomanian indicating a progressive decrease in the detrital supply, driven by rising eustatic sea level. A Ca profile demonstrates variations in carbonate production and dissolution. High total organic carbon (TOC) intervals occur in the upper Albian to mid-Cenomanian and Turonian, and high Ba/Al and Si/Al ratios characterize mid-Cenomanian and younger sediments. Variations in these elements primarily reflect changes in marine productivity, but are also affected by diagenetic processes. A stable carbon isotope curve established from analysis of organic matter (??13Corg) correlates well with published ??13C curves for carbonates from England and Italy. The Cenomanian/Turonian boundary cannot be identified using planktonic foraminifera, because key taxa are absent, but the base of the Turonian is clearly indicated by a sharp fall in ??13C immediately above a major positive excursion. The bottom of the Coniacian is placed below a ??13C minimum, towards the base of the Dicarinella concavata Zone. Combined with the foraminiferal data, the isotopic data enable much improved stratigraphic resolution compared to previous investigations of the formation.

Crespo De Cabrera, S.; Sliter, W.V.; Jarvis, I.

1999-01-01

269

Seismic Evidence for a Vertical Tear in the South American Lithosphere Offshore Venezuela  

NASA Astrophysics Data System (ADS)

In the southeast corner of the Caribbean plate, westward subduction of oceanic (Atlantic) South America transitions to east-west transform with continental South America, forcing the South American lithosphere to tear along its former passive margin. The most widely accepted model for lithospheric detachment, the tensile tear model, envisages oblique convergence causing northwest-dipping subduction. In this model, tensile stress on the subducting slab results in detachment orthogonal to the motion vectors. Conversely, the less commonly accepted shear tear model predicts detachment parallel to the motion vectors along a vertical plane, with shear stress focused at the edge of the propagating transform boundary. The tensile tear model requires significant crustal shortening to produce the 7 km of uplift in the coastal Serrania del Interior and 10 km of subsidence in the Maturin Basin onshore Venezuela. These features have been widely interpreted as the foreland fold and thrust belt and foreland basin of a collisional orogeny. Recent numerical modeling of the lithospheric response to shear tearing has shown, however, that much of the topography of eastern Venezuela can be generated from the propagating detachment, requiring relatively little shortening. We present five types of initially independent seismic data analyses to resolve the lithospheric tear: local seismicity locations, fault plane solutions, receiver functions, wide-angle seismic data inverted for velocity structure, and a regional, balanced cross-section constrained by petroleum industry data. These five datasets image a shear tear extending near-vertically through the entire lithosphere. Confirmation of this type of detachment has implications for diverse locations with similar plate boundary geometries, such as Tonga or the Carpathians, and improves our general understanding of vertical tectonics and associated mantle driving forces.

Clark, S. A.; Levander, A.; Niu, F.; Zelt, C. A.; Sobiesiak, M.; Magnani, M.

2007-12-01

270

Mantle flow beneath northwestern Venezuela: Seismic evidence for a deep origin of the Mérida Andes  

NASA Astrophysics Data System (ADS)

We measured shear wave splitting from SKS data recorded by the national seismic network of Venezuela and a linear broadband PASSCAL/Rice seismic array across the Mérida Andes. The linear array was installed in the second phase of the passive seismic component of the BOLIVAR project to better understand the complicated regional tectonics in western Venezuela. Using the method proposed by Wolfe and Silver (1998), SKS waveforms from 2 to 36 earthquakes, mostly from the Tonga subduction zone, were selected for each of the 23 stations in the region in order to do splitting analysis. The fast polarization directions can be divided into 3 zones, all in agreement with local GPS data: The first zone comprises the stations north of the dextral strike-slip Oca-Ancon fault. These stations show the largest split times (1.6-3.2 s), oriented in a roughly EW direction, and are similar to splitting observations made further to the east along the strike slip plate boundary (Growdon et al., 2009). We attribute this to trench-parallel mantle flow that passes around the northwest corner of the subducting Caribbean plate and along the northern edge of South America as proposed by Russo and Silver (1994), forming an eastward flow beneath the southern Caribbean plate. Zone two is the Mérida Andes, with the right lateral Bocono fault in the center, where split orientations are at ~ N45°E, suggesting that the observed seismic anisotropy is likely caused by lithospheric deformation parallel to the Bocono fault. Zone three is east of the Bocono fault inside the Barinas-Apure Basin, where the measured split times are smaller (~ 0.8 s) with an EW fast direction that is consistent with those observed at the Guarico Basin, Maturin Basin and the Guayana Shield in the east, and are interpreted as orientation with the motion of the continent.

Masy, Jeniffer; Niu, Fenglin; Levander, Alan; Schmitz, Michael

2011-05-01

271

Common Distribution Patterns of Marsupials Related to Physiographical Diversity in Venezuela  

PubMed Central

The aim of this study is to identify significant biotic regions (groups of areas with similar biotas) and biotic elements (groups of taxa with similar distributions) for the marsupial fauna in a part of northern South America using physiographical areas as Operational Geographical Units (OGUs). We considered Venezuela a good model to elucidate this issue because of its high diversity in landscapes and the relatively vast amount of information available on the geographical distribution of marsupial species. Based on the presence-absence of 33 species in 15 physiographical sub-regions (OGUs) we identified Operational Biogeographical Units (OBUs) and chorotypes using a quantitative analysis that tested statistical significance of the resulting groups. Altitudinal and/or climatic trends in the OBUs and chorotypes were studied using a redundancy analysis. The classification method revealed four OBUs. Strong biotic boundaries separated: i) the xerophytic zone of the Continental coast (OBU I); ii) the sub-regions north of the Orinoco River (OBU III and IV); and those south to the river (OBU II). Eleven chorotypes were identified, four of which included a single species with a restricted geographic distribution. As for the other chorotypes, three main common distribution patterns have been inferred: i) species from the Llanos and/or distributed south of the Orinoco River; ii) species exclusively from the Andes; and iii) species that either occur exclusively north of the Orinoco River or that show a wide distribution throughout Venezuela. Mean altitude, evapotranspiration and precipitation of the driest month, and temperature range allowed us to characterize environmentally most of the OBUs and chorotypes obtained. PMID:24806452

Ventura, Jacint; Bagaria, Guillem; Sans-Fuentes, Maria Assumpció; Pérez-Hernández, Roger

2014-01-01

272

Eastern Venezuela Basin's Post-Jurassic evolution as a passive transform margin basin  

SciTech Connect

Passive transform margins are segments of rifted continental margins bounded by transform faults that are active during rifting and that become inactive during drifting. Examples include the northern coast of Brazil and its matching margin along the Liberia-Nigeria coast. We propose that the northern margin of the Eastern Venezuela Basin was dominantly a passive transform margin during the Cretaceous and early Paleogene, rather than a purely passive margin. Published microplate reconstructions of the southern Caribbean show Jurassic separation of the Bahamas platform from northern South America along a northwest-trending transform fault postulated to lie just northeast of Trinidad and the Guianas. We conjecture that the [open quotes]Deflexion de Barcelona[close quotes] (a northwest-trending zone of strike slip faults along the southwestern edge of the Serrania del Interior) is controlled by a basement geofracture that is the onshore expression of Jurassic transform fault southwest of and subparallel to the southwestern Bahamas transform. Implications of this conjecture for the Eastern Venezuela Basin include: (1) absence of McKenzie-type regional crustal stretching, Mesozoic thermal anomaly, and Mesozoic thermal-tectonic subsidence; (2) abrupt rather than gradual seaward changes in crustal thickness; (3)abrupt lateral changes in thickness and facies of Mesozoic sediments, as in the Piaui-Ceara basins of northern Brazil; (4) tendency for structural styles developed during Neogene compression to include more strike-slip faults and en enchelon fold sets (because of reactivation of Mesozoic transforms) than would be expected by structural inversion of a purely passive margin.

George, R.P. Jr. (EGEP Consultores, Caracas (Venezuela)); Sams, R.H. (Sams Exploration Inc., Canyon Lake, TX (United States))

1993-02-01

273

Common distribution patterns of marsupials related to physiographical diversity in Venezuela.  

PubMed

The aim of this study is to identify significant biotic regions (groups of areas with similar biotas) and biotic elements (groups of taxa with similar distributions) for the marsupial fauna in a part of northern South America using physiographical areas as Operational Geographical Units (OGUs). We considered Venezuela a good model to elucidate this issue because of its high diversity in landscapes and the relatively vast amount of information available on the geographical distribution of marsupial species. Based on the presence-absence of 33 species in 15 physiographical sub-regions (OGUs) we identified Operational Biogeographical Units (OBUs) and chorotypes using a quantitative analysis that tested statistical significance of the resulting groups. Altitudinal and/or climatic trends in the OBUs and chorotypes were studied using a redundancy analysis. The classification method revealed four OBUs. Strong biotic boundaries separated: i) the xerophytic zone of the Continental coast (OBU I); ii) the sub-regions north of the Orinoco River (OBU III and IV); and those south to the river (OBU II). Eleven chorotypes were identified, four of which included a single species with a restricted geographic distribution. As for the other chorotypes, three main common distribution patterns have been inferred: i) species from the Llanos and/or distributed south of the Orinoco River; ii) species exclusively from the Andes; and iii) species that either occur exclusively north of the Orinoco River or that show a wide distribution throughout Venezuela. Mean altitude, evapotranspiration and precipitation of the driest month, and temperature range allowed us to characterize environmentally most of the OBUs and chorotypes obtained. PMID:24806452

Ventura, Jacint; Bagaria, Guillem; Sans-Fuentes, Maria Assumpció; Pérez-Hernández, Roger

2014-01-01

274

Settlement patterns in the eastern coast of Maracaibo Lake, Venezuela : evaluation of existing settlements and model for a low income sector of El Menito new town  

E-print Network

This thesis is divided in two parts; The First part is the physical analysis of residential settlements in the Eastern Coast of Maracaibo Lake, Venezuela. The work is based on surveys, evaluations and comparisons of four ...

Rodriguez Navas, Humberto José

1983-01-01

275

Physical and chemical properties of fruit and seeds eaten by Pithecia and Chiropotes in Surinam and Venezuela  

Microsoft Academic Search

Pithecia pithecia andChiropotes satanas are seed predators that eat fruits with hard pericarps. We measured resistance to puncturing and crushing of fruit and seeds eaten by these two pitheciins at two localities: in evergreen rain forest at Raleighvallen-Voltzberg, Surinam, and in tropical dry\\/transitional moist forest on islands in Guri Lake, Venezuela. Average measurements of pericarp hardness were similar at both

Warren G. Kinzey; Marilyn A. Norconk

1993-01-01

276

N2O and NO emissions from soils of the Northern Part of the Guayana Shield, Venezuela  

Microsoft Academic Search

Soil fluxes of N2O and No were measured in a scrub grass savanna and a nearby semideciduous forest in the savanna climatic region of Venezuela, during October 1988. The forest soil produces significantly larger emissions of N2O (ranging from 5.7 to 25.0×109 molecules cm-2 s-1) than the savanna soil (-3.6 to 14.0×109 molecules cm-2 s-1). This suggests that ``long term''

Eugenio Sanhueza; Dieter Scharffe; Loreto Donoso; Paul J. Crutzen

1990-01-01

277

The Venezuelan gas industry. Venezuela and other South American countries: Impact on imports into the U.S.  

SciTech Connect

The role of Venezuela as a supplier of natural gas and derivative products to international markets will experience significant growth in the medium to long term, in the context of expected market opportunities and the development plans envisaged regarding crude oil production. Venezuela has a very large natural gas resource base, which presently amounts to 287 trillion cubic feet (TCF) in terms of proven, probable and possible reserves. Local consumption is highly concentrated in the oil, petrochemicals, aluminum, steel and electricity generation sectors. At the current consumption level of 1.1 TCF/year, proven reserves would supply the country`s requirements for over 120 years. Probable and possible reserves would more than double this figure. Certainly, this is an indication that one is dealing with a gas surplus country with significant potential for growth towards the exports markets. In this regard, Venezuela`s competitive position is further strengthened by the fact that a large portion of its reserves are associated to crude oil, which allows for low production and handling costs, and a relatively high liquid content. It is expected that the natural gas industry will grow rapidly over the coming years. A significant number of gas projects will be developed, including the expansion of existing ones and the construction of new facilities for recovery of natural gas liquids, the expansion of city methane networks replacing LPG as a domestic and industrial fuel, the construction of ethane recovery units for petrochemical uses, etc., all of which represent an additional liquids production of more than 100 {times} 10{sup 3} bbl/d that could be exported to the US and The Caribbean.

Mantellini, R. [PDVSA, Caracas (Venezuela)

1995-11-01

278

Biomarker-based paleo-record of environmental change for an eutrophic, tropical freshwater lake, Lake Valencia, Venezuela  

Microsoft Academic Search

The lipids in a sediment core from Lake Valencia, a hypereutrophic freshwater lake in Venezuela, are examined to understand\\u000a environmental changes over the last ?13,000 years. From the latest Pleistocene to the earliest Holocene, total organic carbon\\u000a (TOC) substantially increased from 2.2 to 10%, while total organic carbon over total nitrogen (TOC\\/TN) decreased from as high\\u000a as 34 to as low

Yunping Xu; Rudolf Jaffé

2008-01-01

279

Feeding ecology and postural behaviour of the three-toed sloth ( Bradypus variegatus flaccidus) in northern Venezuela  

Microsoft Academic Search

We studied the diet, activity budget, vertical ranging, and postural behaviour in relation to weather of the three-toed sloth (Bradypus variegatus flaccidus) in disturbed montane forest remnants (1150m asl) in northern Venezuela. Sloths spent most (72.9%) of their time resting and had a nearly exclusive (99.4%) leaf diet. While resting they assumed a sitting – not hanging – posture mostly

B. Urbani; C. Bosque

2007-01-01

280

Population structure of guppies in north-eastern Venezuela, the area of putative incipient speciation  

PubMed Central

Background Geographic barriers to gene flow and divergence among populations in sexual traits are two important causes of genetic isolation which may lead to speciation. Genetic isolation may be facilitated if these two mechanisms act synergistically. The guppy from the Cumaná region (within the Cariaco drainage) of eastern Venezuela has been previously described as a case of incipient speciation driven by sexual selection, significantly differentiated in sexual colouration and body shape from the common guppy, Poecilia reticulata. The latter occurs widely in northern Venezuela, including the south-eastern side of Cordillera de la Costa, where it inhabits streams belonging to the San Juan drainage. Here, we present molecular and morphological analyses of differentiation among guppy populations in the Cariaco and San Juan drainages. Our analyses are based on a 953 bp long mtDNA fragment, a set of 15 microsatellites (519 fish from 20 populations), and four phenotypic traits. Results Both microsatellite and mtDNA data showed that guppies inhabiting the two drainages are characterised by a significant genetic differentiation, but a higher proportion of the genetic variance was distributed among populations within regions. Most guppies in the Cariaco drainage had mtDNA from a distinct lineage, but we also found evidence for widespread introgression of mtDNA from the San Juan drainage into the Cariaco drainage. Phenotypically, populations in the two regions differed significantly only in the number of black crescents. Phenotypic clustering did not support existence of two distinct groupings, but indicated a degree of distinctiveness of Central Cumaná (CC) population. However, CC population showed little differentiation at the neutral markers from the proximate populations within the Cariaco drainage. Conclusions Our findings are consistent with only partial genetic isolation between the two geographic regions and indicate that the geographic barrier of Cordillera de la Costa has not played an important role in strengthening the incomplete pre-zygotic reproductive barrier between Cumaná and common guppy. Significant phenotypic differentiation between genetically similar (in terms of neutral variation) populations suggests that mate choice can maintain divergence at sexually selected traits despite gene flow. However, neither genetic nor phenotypic clustering supported delineation of two species within the region. PMID:24533965

2014-01-01

281

Geophysical studies for the identification of basin effects in urban areas in Venezuela  

NASA Astrophysics Data System (ADS)

Urban areas in northern Venezuela are subject to a moderate seismic hazard due to the interactions between the Caribbean and south American plates, which has been evidenced by historical damaging earthquakes as for example the 1812 and the 1967 earthquakes with a magnitude of 7.2 and 6.5, respectively. Strong damages in Caracas during the 1967 earthquake have been asociated to site effects produced by the sediment filled basin. This situation can be observed in most of the big cities in northern Venezuela, which initially developped on plain areas with quaternary basin fills of up to 500 m within mountainous areas, as for example Caracas, Maracay and Barquisimeto. In the mid- 1990ies FUNVISIS started to promote geophysical studies to investigate the shape and the properties of the basin fills in order to contribute to the earthquake disaster reduction. Methods applied for the investigations are gravimetry, microtremor measurements, seismic refraction, among others. In Caracas, a total of 350 m of cuaternary sediments with an average S-wave velocity of about 850 m/s have been derived by seismic investigations. The corresponding predominant periods from microtremor measurements amount up to 2.2 s. Integrating drilling information and 3D gravimetric modeling a detailed picture of the bedrock - sediment interface could be obtained. Results from numerical modelling as well as from experimental transfer function indicate amplifications point to amplifications of a factor of more than 10 related to the deep basin area. In Barquisimeto Metropolitan Area, sediment thickness reaches up to 500 m in the fast growing Cabudare area. Actually, modelling of a recent seismic refraction campaign is in progress, but predominant periods up to 3.0 s in the deepest part of the valley and gravity modelling point to the same order of cuaternary sediments. In other cities, as for example Carora and Mérida, geophysical studies are in progress, first with gravimetric and microtremor measurements which point to sediment with more than 150 m thickness. The subsoil information from geophysical studies will be used to define the distribution of microzones of equal seismic response in order to determine PSHA spectra. Contribution to projects FONACIT 200400738 and FONACIT-ECOS Nord 2004000347.

Schmitz, M.; Rocabado, V.; Sánchez, J.; Reinoza, C.; Amaris, E.; Cornou, C.

2007-05-01

282

Rupture history of the 1997 Cariaco, Venezuela, earthquake from teleseismic P waves  

USGS Publications Warehouse

A two-step finite-fault waveform inversion scheme is applied to the broadband teleseismic P waves recorded for the strike-slip, Cariaco, Venezuela, earthquake of 9 July 1997 to recover the distribution of mainshock slip. The earthquake is first analyzed using a long narrow fault with a maximum rise time of 20 sec. This line-source analysis indicates that slip propagated to the west with a constant rupture velocity and a relatively short rise time. The results are then used to constrain a second inversion of the P waveforms using a 60-km by 20-km two-dimensional fault. The rupture shows a zone of large slip (1.3-m peak) near the hypocenter and a second, broader source extending updip and to the west at depths shallower than 5 km. The second source has a peak slip of 2.1 meters and accounts for most of the moment of 1.1 × 1026 dyne-cm (6.6 Mww) estimated from the P waves. The inferred rupture pattern is consistent with macroseismic effects observed in the epicentral area.

Mendoza, C.

2000-01-01

283

Estimation of undiscovered deposits in quantitative mineral resource assessments-examples from Venezuela and Puerto Rico  

USGS Publications Warehouse

Quantitative mineral resource assessments used by the United States Geological Survey are based on deposit models. These assessments consist of three parts: (1) selecting appropriate deposit models and delineating on maps areas permissive for each type of deposit; (2) constructing a grade-tonnage model for each deposit model; and (3) estimating the number of undiscovered deposits of each type. In this article, I focus on the estimation of undiscovered deposits using two methods: the deposit density method and the target counting method. In the deposit density method, estimates are made by analogy with well-explored areas that are geologically similar to the study area and that contain a known density of deposits per unit area. The deposit density method is useful for regions where there is little or no data. This method was used to estimate undiscovered low-sulfide gold-quartz vein deposits in Venezuela. Estimates can also be made by counting targets such as mineral occurrences, geophysical or geochemical anomalies, or exploration "plays" and by assigning to each target a probability that it represents an undiscovered deposit that is a member of the grade-tonnage distribution. This method is useful in areas where detailed geological, geophysical, geochemical, and mineral occurrence data exist. Using this method, porphyry copper-gold deposits were estimated in Puerto Rico. ?? 1993 Oxford University Press.

Cox, D.P.

1993-01-01

284

Breeding biology and natural history of the Slate-throated Whitestart in Venezuela  

USGS Publications Warehouse

We provide details on the breeding biology of the Slate-throated Whitestart (Myioborus miniatus) from 126 nests found during seven breeding seasons, 2002-2008, at Yacamb?? National Park, Venezuela. Nesting activity peaked in late April and May. Only the female built the nest and incubated the eggs. Males rarely visited the nest during these stages. Mean clutch size (2.1 ?? 0.04 eggs, n = 93) was the smallest recorded for the Slate-throated Whitestart. Incubation and nestling period lengths were 15.3 ?? 0.31 (n = 21) and 10.8 ?? 0.24 (n = 7) days, respectively. Attentiveness (% of time on the nest) during incubation (59 ?? 1.6%, n = 52) was similar to other tropical warblers and much lower than northern relatives. This caused a relatively low egg temperature (34.40 ?? 0.33u C, n = ?? nests, 20 days) compared with north temperate birds. Both parents fed nestlings and increased their provisioning rates with nestling age. Growth rate based on nestling mass (k = 0.521 ?? 0.015) was faster than for other tropical passerines but slower than northern relatives. Predation was the main cause of nesting failure and rate of predation increased with age of the nest. An estimated 15% of nests were successful based on an overall Mayfield daily predation rate of 0.053 ?? 0.007. This study confirms a strong latitudinal variation in life history traits of warblers. ?? 2010 by the Wilson Ornithological Society.

Ruggera, R.A.; Martin, T.E.

2010-01-01

285

Geomorphic effects of large debris flows and flash floods, northern Venezuela, 1999  

USGS Publications Warehouse

A rare, high-magnitude storm in northern Venezuela in December 1999 triggered debris flows and flash floods, and caused one of the worst natural disasters in the recorded history of the Americas. Some 15,000 people were killed. The debris flows and floods inundated coastal communities on alluvial fans at the mouths of a coastal mountain drainage network and destroyed property estimated at more than $2 billion. Landslides were abundant and widespread on steep slopes within areas underlain by schist and gneiss from near the coast to slightly over the crest of the mountain range. Some hillsides were entirely denuded by single or coalescing failures, which formed massive debris flows in river channels flowing out onto densely populated alluvial fans at the coast. The massive amount of sediment derived from 24 watersheds along 50 km of the coast during the storm and deposited on alluvial fans and beaches has been estimated at 15 to 20 million m3. Sediment yield for the 1999 storm from the approximately 200 km2 drainage area of watersheds upstream of the alluvial fans was as much as 100,000 m3/km2. Rapid economic development in this dynamic geomorphic environment close to the capital city of Caracas, in combination with a severe rain storm, resulted in the death of approximately 5% of the population (300,000 total prior to the storm) in the northern Venezuelan state of Vargas. ?? 2006 Gebru??der Borntraeger.

Larsen, M.C.; Wieczorek, G.F.

2006-01-01

286

Estimation of the intrinsic absorption and scattering attenuation in Northeastern Venezuela (Southeastern Caribbean) using coda waves  

USGS Publications Warehouse

Northeastern Venezuela has been studied in terms of coda wave attenuation using seismograms from local earthquakes recorded by a temporary short-period seismic network. The studied area has been separated into two subregions in order to investigate lateral variations in the attenuation parameters. Coda-Q-1 (Q(c)-1) has been obtained using the single-scattering theory. The contribution of the intrinsic absorption (Q(i)-1) and scattering (Q(s)-1) to total attenuation (Q(t)-1) has been estimated by means of a multiple lapse time window method, based on the hypothesis of multiple isotropic scattering with uniform distribution of scatterers. Results show significant spatial variations of attenuation: the estimates for intermediate depth events and for shallow events present major differences. This fact may be related to different tectonic characteristics that may be due to the presence of the Lesser Antilles subduction zone, because the intermediate depth seismic zone may be coincident with the southern continuation of the subducting slab under the arc.

Ugalde, A.; Pujades, L.G.; Canas, J.A.; Villasenor, A.

1998-01-01

287

Predominant Periods and Shear Wave Velocity an indicator for Sediment Thickness, Caracas, Venezuela  

NASA Astrophysics Data System (ADS)

Within the Caracas seismic microzoning project, carried out by Venezuelan Foundation for Seismological Research (FUNVISIS), more than 1500 single measurements of ambient noise have been done since mid-90's in order to determinate fundamental periods of soil. In this work we show the result of these single stations applying H/V analysis, with period values between 0.2s and 2.4s, we propose a new relationship to estimate sediment thickness from period values, including the effect of the surface sediment layers, considering the values of shear-wave velocities for the first 30 m (Vs30) and the Vs value of the sedimentary layer, just above bedrock. The results indicate that this relationship generates more accurate estimates of sediment thickness comparing with depth values from other geophysical methods; this relationship was calibrated with information from 4 depth boreholes in Caracas, obtaining accurate depth values. The main objective of this new relationship is consider local information of soils in other cities, for local relationships between periods and sediment thickness, to generate accurate sediment thickness estimates from environmental noise measurements within seismic microzoning projects in Venezuela's most important cities.

Rocabado, V.; Schmitz, M.

2013-05-01

288

Geochemical study of the organic matter from Querecual formation, Anzoategui State, Venezuela  

SciTech Connect

Kerogen and bitumen fractions extracted from twenty-one limestone samples from kind section of Querecual formation (Querecual River, Anzoategui State, Venezuela) were analyzed for their content of Co, Cr, Fe, Mn, Mo, Ni, S, Sr, V and Zn. S and trace-metals content from the kerogen fraction were used to obtain information about paleoenvironmental sedimentation conditions of the Querecual formation. Based on these data, and especially on the V and S content variations plus V/Ni, VIV+Ni and Mo/Mo+Cr ratios, we confirm an ancient-reducer condition on this region according with a sulfur-reducer environment. Trace-metals content variations from the bitumen fraction along the study section were used as possible primary migration indicators. V and Ni were the only elements showing a clear tendency to be used as primary migration indicators. The observed tendency allows us to postulate a vertical migration of the bitumen, from center to the extremes of the section.

Garban, G.; Lopez, L.; Lo Monaco, S.; Lira, A. [Universidad Central de Venezuela, Caracas (Venezuela)

1996-08-01

289

Diet seasonality and food overlap among fishes of the upper Orituco stream, northern Venezuela.  

PubMed

The diets of four diurnal fish species (Creagrutus bolivari, Knodus deuterodonoides, Knodus sp. and Poecilia reticulata) were examined during a year in the Orituco stream at northern Venezuela. The fishes were sampled monthly from February 1991 to March 1992 (except October 1991 and February 1992) in the stream main channel with a beach seine and a cast net. Diet is reported as frequency of occurrence and numeric proportion because variation in prey sizes was small. Non-parametric statistical tests were applied. A total of 18 distinct prey items were found in stomachs. The diet of these fishes consisted of aquatic insects (Coleoptera, Diptera, Hemiptera, Odonata, Plecoptera and Trichoptera), allochthonous plant matter (fragments of leaves and seeds), microalgae (Chlorophyta and Bacillariophyceae) and terrestrial arthropods (Coleoptera, Diptera, Hymenoptera and Arachnida). The low percentage of empty guts and the high fullness percentage of guts suggest that food was always abundant. Aquatic insects were more important in the dry season (November-April) while plant matter and terrestrial arthropods increased in the wet season (May-October). The Proportional Similarity Measure (PS) was high between characid species and low between characids and P. reticulata in the dry season. PS decreased during the wet season because of a reduction in aquatic insect consumption. The seasonal diet shift indicated the greater importance of allochthonous food only in the wet season. PMID:11795147

Ortaz, M

2001-03-01

290

The hydrocarbon habitat of northern South America: Colombia-Venezuela-Trinidad  

SciTech Connect

A prolific hydrocarbon province extends across the northern margin of South America from Colombia to east of Trinidad. Two key components are a world-class source rock, formed on a regional Late Cretaceous passive margin, and a complex tectonic setting in which a variety of structural and stratigraphic traps, reservoirs, seals and hydrocarbon kitchens have evolved through time. Convergence between the Farallon and Caribbean plates with South America culminated in the late Cretaceous-early Palaeogene with emplacement of Colombia`s Central Cordillera in the west and a nappe-foreland basin system in the north. Regional hydrocarbon generation probably occurred below associated basins. Subsequent oblique convergence between the Caribbean and South America, partitioned into strike-slip and compressional strain, generated an eastward migrating and ongoing uplift-foredeep (kitchen) system from central Venezuela to Trinidad. Similarly, oblique interaction of western Colombia with the Nazca Plate caused segmentation of the earlier orogen, northward extrusion of elements such as the Maracaibo Block, and eastward migration of uplift progressively dividing earlier kitchens into localized foredeeps.

James, K.H. [Conoco, Inc., Houston, TX (United States)

1996-08-01

291

Geological Studies in eastern Venezuela and Trinidad from Cretaceous passive margin to Neogene transpressional thrust belt  

SciTech Connect

Sedimentological and structural analyses of Trinidad's Northern and Central ranges and Venezuela's Serrania del Interior have led to new interpretations of northeastern. South America's tectonic evolution within the Southern Caribbean Plate Boundary Zone. Medial ( ) Jurassic through early Cenozoic passive margin sediments make up the majority of these areas and were deposited somewhat to the WNW (between 80 and 130 km for Northern Range of Trinidad) of their present positions prior to structural shortening. Neogene southeastward displacement of Jurassic-Cretaceous passive slope and rise sediments (Northern Range) drove propagation of thrusts southward into the Serrania and Central ranges. Displacements were driven by migration of the Caribbean Plate relative to South America. Thus, the Serrania and Central ranges are the western hemisphere's only exposed Mesozoic-Cenozoic passive Atlantic margin stratigraphic section. As such, they provide a Cretaceous-Paleogene record of passive margin sedimentation at a thermally subsiding margin where the complicating effects of tectonism are absent. This makes these sections especially suited for studies of eustatic sea level behavior. Preliminary assessments are shown which suggest that sea level changes for Cretaceous to Paleogene time are not as pronounced as the frequent large and rapid sea level falls and rises that are promoted by some.

Algar, S.T.; Erikson, J.E.; Pindell, J.L. (Dartmouth Coll., Hanover, NH (United States))

1991-03-01

292

Neotectonic map of Venezuela and neighboring areas at scale 1:2,000,000  

SciTech Connect

An updated neotectonic map of Venezuela is presented, synthetizing works carried out by the FUNVISIS Earth Science Workgroup since 1979 and which includes the northeastern Colombian region and Trinidad island. The map shows a main deformation belt, some 40 to 100 km wide, with the most important evidences of quaternary activity and considered as the boundary between South America and Caribbean plates. Two secondary belts defining the borders of the Maracaibo Block are outlined as well. In the main belt, the major features are represented by the inter-connected strike-slip fault systems of Bocono-San Sebastian-El Pilar-Los Bajos-El Soldado. Important tectonic complications can be observed along this belt, like the [open quotes]Pamplona indenter[close quotes] associated structures that connects to the frontal fault system of the Colombian Eastern Range in the western end, and in the eastern end the high compressive zone of Trinidad that constitutes a transition between the strike-slip fault system and the subduction zone of the lesser Antilles. In addition, oblique secondary systems can be seen at both sides of the principal deformation axis without crossing it. Two other important secondary systems, the Santa Marta-Bucaramanga and the Oca-Ancon faults, and the main fault of Bocono define the Block of Maracaibo, which is characterized by important internal deformations.

Beltran, C. (Venezuelan Foundation for Seismological Research (FUNVISIS), Caracas (Venezuela))

1993-02-01

293

Diagenesis and reservoir characterization of the Cretaceous-Tertiary sequence, eastern Venezuela  

SciTech Connect

The giant El Furrial field Maturin subbasin is the most important oil field discovered in Venezuela in the last three decades. The average oil column has a thickness of 400 m and the reservoirs consist of essentially sandy siliciclastic sediments of nearshore-shallow marine origin. The oil's API gravity ranges from light to extra heavy and occurs in a stratified manner in the reservoirs. A total of 1,080 m of core from the producing sequence was studied through x-ray diffraction scanning electron microscopy, and petrography. This data, along with petrophysical measurements, show a clear differentiation between the Upper Cretaceous and the Oligocene reservoirs. The Upper Cretaceous reservoirs are characterized by relatively fine and uniform grain size, subarkosic composition with common volcanic rock fragments, high degree of chemical and mechanical compaction highly illitic mixed-layer I/S assemblage with less than 10% expandable layers, and ubiquitous baroque dolomite. Additionally, porosity and permeability values are persistently low. Clearly, the Cretaceous sediments are diagenetically mature and may indicate diagenetic transformation at greater depths or under a different thermal regime. In contrast the coarser grained Oligocene reservoirs of quartz arenitic composition show a lesser diagenetic overprint, and greater porosity and permeability. Porosity is dominantly secondary due to cement and grain (mostly quartz) dissolution, as well as tectonically induced grain fracturing. Common kaolinite and minor amounts of I/S with up to 20% of expandable layers attest to a lower diagenetic regime than in the Cretaceous reservoirs.

Aquado, B.; Ghosh, S.; Isea, A. (Intevep, S.A., Caracas (Venezeula))

1990-05-01

294

Chemical kinetic model of hydrocarbon generation, expulsion, and destruction applied to the Maracaibo basin, Venezuela  

SciTech Connect

This paper describes the development and application of a compositional chemical model of hydrocarbon generation, expulsion,a nd destruction for the Cretaceous La Luna Formation source rock of the Maraciabo basin, Venezuela. Applications include both laboratory and geological settings. Laboratory pyrolysis experiments were used to study bulk oil generation, expulsion, and associated changes in composition of the kerogen, extractable organic matter, and expelled and unexpelled hydrocarbons. The laboratory experiments were also used to determine kinetic parameters to quantitatively describe organic reactions, via a computer model that also includes simulation of pressure-driven primary expulsion, over widely varying conditions. We show that the chemical model accuratley simulates the experimental results. Thermal history models for wells in the Maraciabo basin were used to simulate hydrocarbon generation and pore pressure development in the La Luna Formation and expulsion into nearby Cretaceous reservoirs. Results of the modeling indicate that both compaction disequilibrium and organic maturation play important roles in the development of excess pore pressure in the La Luna Formation. The model simulation of the variation of indicators such as Rock-Eval parameters and extract and oil compositions shows generally good agreement with measurements from remaining kerogen, oils, and extracts recovered from the La Luna Formation and from nearby Cretaceous reservoirs.

Sweeney, J.J.; Braun, R.L.; Burnham, A.K. [Lawrence Livermore National Lab., CA (United States)] [and others

1995-10-01

295

Chromoblastomycosis in children and adolescents in the endemic area of the Falcón State, Venezuela.  

PubMed

The present paper describes 22 cases of chromoblastomycosis (CBM) caused by Cladophialophora carrionii in children and adolescents (2-19 years old). The patients were seen between 1992 and 2004 and all resided in a CBM endemic area in the semi-arid zone of the Falcón state, Venezuela. Twelve of the 22 patients (54.55%) had close relatives who also had CBM and 19 (86.36%) were male. Lesions consisted of erythematous papules with desquamation or squamous plaques (0.12-14.19 cm in diameter), located primarily on the upper limbs (77.27% of patients). Thirteen of the patients were treated with topical 5-fluorouracil (5-FU; 1% cream), seven with topical ajoene (0.5% gel) and two had electrodesiccation and/or fulguration. Two patients who did not respond to 5-FU were treated with oral itraconazole (100 mg/day for 1 month). Complete clinical and mycological remission was achieved in 17/20 (85%) of the patients treated with 5-FC, ajoene and electrodesiccation and/or fulguration. In addition, similar results were obtained with the two patients who received itraconazole therapy. These cases emphasize the importance of early diagnosis in difficult-to-treat mycotic diseases such as CBM. By early intervention we were able to employ topical treatment with a minimum of adverse effects to achieve a high percentage of favorable therapeutic responses. The patients were thus able to avoid the evolution of the chronic, deforming and incapacitation clinical manifestations associated with CBM. PMID:16882614

Pérez-Blanco, M; Hernández Valles, R; García-Humbría, L; Yegres, F

2006-08-01

296

Geological photointerpretation of the Paraguana Peninsula using ERTS-A multispectral photography. [Venezuela  

NASA Technical Reports Server (NTRS)

A methodology was developed to evaluate multispectral analysis of orbital imagery on the interpretation of geology, coastal geomorphology and sedimentary processes. The images analyzed were obtained during the pass of ERTS satellite over the center region of Venezuela on October 19, 1972. ERTS-1 multispectral images in black and white paper copies and transparencies of the 4 bands and false color composites at scales of 1:1,000,000 and 1:500,000 were interpreted. Lithology and outcrop patterns of the following geological formations have been interpreted: igneous and metamorphic basement of Cocodite and Santa Ana, Jurassic-Cretaceous metamorphics of Pueblo Nuevo, Cantaure Miocene-Pliocene sediments, and Quaternary alluvium, dunes, beach ridges, bars and reefs. A prominent and extensive Paraguana tonal anomaly shaped as an 8 has been discovered at the NW of the Peninsula. Its erosional origin has exposed light toned lower beds at the center, with additional evidence of topographic depression and development of underground drainage of karst origin. Coastal geomorphology, its processes and energy has been interpreted with the help of wind direction analysis (ENE-WSW) at sea level through the orientation of transported materials (water vapor, water and sediments) by clouds, waves, sea current, plumes of suspended sediments associated to river outlets, dunes, sediment sources and shore-line orientation.

Albrizzio, C.

1974-01-01

297

The fused anthranilate synthase from Streptomyces venezuelae functions as a monomer.  

PubMed

Recently, we showed that the fused chorismate-utilizing enzyme from the antibiotic-producing soil bacterium Streptomyces venezuelae is an anthranilate synthase (designated SvAS), not a 2-amino-2-deoxyisochorismate (ADIC) synthase, as was predicted based on its amino acid sequence similarity to the phenazine biosynthetic enzyme PhzE (an ADIC synthase). Here, we report the characterization of SvAS using steady-state kinetics, gel filtration chromatography, and laser light scattering. The recombinant His-tagged enzyme has Michaelis constants Km with respect to substrates chorismate and glutamine of 8.2 ± 0.2 ?M and 0.84 ± 0.05 mM, respectively, and a catalytic rate constant k cat of 0.57 ± 0.02 s(-1) at 30 °C. Unlike most other anthranilate synthases, SvAS does not utilize ammonia as a substrate. The enzyme is competitively but non-cooperatively inhibited by tryptophan (K i = 11.1 ± 0.1 ?M) and is active as a monomer. The finding that SvAS is a monomer jibes with the variety of association modes that have been observed for anthranilate synthases from different microorganisms, and it identifies the enzyme's minimal functional unit as a single TrpE-TrpG pair. PMID:25355158

Ashenafi, Meseret; Reddy, Prasad T; Parsons, James F; Byrnes, W Malcolm

2015-02-01

298

Ages and depositional environments of Paleogene rocks in the southern Maracaibo Basin, Venezuela  

SciTech Connect

Detailed studies of Paleogene rocks exposed in road cuts and rivers along the north flank of the Merida Andes in Venezuela provide a means of assisting the interpretation of subsurface data and therefore assessment of the hydrocarbon potential of the Southern Maracaibo Basin. Thick sections at Rio Chama, Rio Lora and Rio Lobaterita, together with many smaller outcrop localities, were measured and sampled to determine the ages and depositional environments of Paleogene formations. Observations and measurements taken at the outcrop include gamma ray signature, bed thickness, mineralogy, and associated sedimentary structures. Extensive sets of samples were taken for paleontological (especially palynology) analyses. This paper highlights the significant geological characteristics of the Barco, Los Cuervos, Mirador, and Carbonera formations, illustrated with measured sections showing gamma ray, geochemical, and palynological abundance logs. These observations together with proprietary subsurface data have made it possible to construct maps of Paleogene paleogeography of the Southern Maracaibo Basin, providing an understanding of the depositional environments and regional extent of potential hydrocarbon reservoirs and seals.

Pocknall, D.T. [Amoco, Exploration & Production Technology Group, Houston, TX (United States); Erlich, R.N. [Amoco, Worldwide Exploration Business Group, Houston, TX (United States)

1996-08-01

299

Chronology of mercury enrichment factors in reef corals from western Venezuela.  

PubMed

Mining and deforestation in the early 20th century, the development of petrochemical industries during the 1950s, and the constant weathering of natural deposits of cinabrium (HgS) have made Golfo Triste, Venezuela, a region impacted by mercury (Hg). We studied the chronology of Hg in coral skeletons of Siderastrea siderea (1 colony, 1900-1996) and Montastraea faveolata (2 colonies, 1930-1999) from Parque Nacional San Esteban. Maximum values of Hg/Ca ratios and standard deviations of Hg enrichment factors occurred in the 1940s, 1960s, and 1980s, and matched maxima of decadal rainfall. Values from the 1950s and 1970s matched periods of abundant but constantly decreasing rainfall and hence were best explained by the combination of runoff and the sudden bioavailability of Hg in the region. This sudden availability likely was associated with activities of the chlorine-caustic soda and fertilizer plants of Morón petrochemical complex, industries that started producing large amounts of Hg in 1958. PMID:19012938

Ramos, Ruth; Cipriani, Roberto; Guzman, Hector M; García, Elia

2009-02-01

300

[Spatio-temporal variation of subtidal meiofauna in a sandy beach from Northeastern Venezuela].  

PubMed

Meiofauna organisms that play an important role in the trophic ecology of soft bottom benthos, have short life cycles and they respond quickly to disturbance and pollution. The present study shows the spatio-temporal variation ofsubtidal meiofauna (metazoans passing a 500im sieve but retained on meshes of 40-63micro m) in four shallow subtidal stations. Samples were taken in the sandy beach of San Luis, in the Northeastern coast of Venezuela, from October 2005 until September 2006. For this, three replicate sediment core samples (4.91cm2), were collected monthly to a depth of 10cm into the sediment, and preserved in 6% formalin stained with rose Bengal. Specimens of 14 meiofaunal groups (Foraminifera excluded) were collected, being the nematodes, ostracods and harpacticoid copepods the most abundant. Monthly density was comprised between 64 and 503ind./10cm2, and mean density of stations between 173 and 449ind./10cm2. There is a trend of low densities from October to February (end of the rainy season until the middle of the dry season). The San Luis beach control of the meiofaunal community is shared by climatic conditions and by the biology of the species found. The meiofauna mean density in San Luis beach (263ind./10cm2) was low when compared to other studies in tropical areas. PMID:23894963

Arana, Ildefonso Liñero; Ojeda, Sol; Amaro, María Elena

2013-03-01

301

[Distribution and taxonomy of Pyrgophorus platyrachis (Caenogastropoda: Hydrobiidae) in the Sistema de Maracaibo, Venezuela].  

PubMed

The presence of a microgastropod identified as Potamopyrgus sp. was detected previously in the Maracaibo System; nevertheless, a detailed morphological analysis identified this snail in other genera. The objective of this work is to update the distribution and taxonomy of Pyrgophorus platyrachis in the Maracaibo System, Venezuela in samples obtained between 2001 and 2009. The presence of hundreds of individuals of P. platyrachis were observed in the estuary, indeed in the localities of the Gran Eneal lagoon (4 111 snails), Peonías lagoon (229 snails), Punta Capitán Chico (758 snails), San Francisco (2 517 snails), Curarire (240 snails), Apon River mouth (173 snails), Ojeda City (240 snails), Bachaquero (128 snails) and Tomoporo de Agua (385 snails). We performed a taxonomical analysis, and emphasized in ecological aspects, such as the distribution of the species and habitat features, as near vegetation and type of associated sediment. We found three morphotypes of the species, one smooth, another with spiral striations and the other with spines. Smooth morphotype was exclusive of the Gran Eneal lagoon, Peonías lagoon, Punta Capitan Chico and Apon River mouth localities, whereas the other two morphotypes were found together in the remaining localities. According to our detailed anatomical and taxonomical analysis we propose a synonymy between P. platyrachis and the other species described like Pyrgophorus parvulus and Pyrgophorus spinosus. PMID:22017122

Nava, Mario; Severeyn, Héctor; Machado, Nakary

2011-09-01

302

Assessment of Fatty Liver Syndrome and Its Predisposing Factors in a Dairy Herd from Venezuela  

PubMed Central

The present on-farm research evaluated the occurrence of fatty liver syndrome and its predisposing risk factors for multiparous dairy cows from a commercial herd in Venezuela. Liver biopsy samples were collected at 35 days (d) prepartum (Holstein, n = 14; Holstein × Carora crossbred, n = 17) as well as 1 to 7?d (Holstein, n = 8; Holstein × Carora crossbred, n = 11) and 28 to 35?d (Holstein, n = 6; Holstein × Carora crossbred, n = 14) postpartum in order to analyse hepatic triacylglycerols (TAG, % wet basis) and glycogen concentrations. At postpartum, an occurrence of 72.0% for severe fatty liver along with 73.5% of subclinical ketosis (SCK) was found. The multiple regression model that best explained the association between milk production in the previous lactation (MYP) and TAG at first week postpartum was as follows: TAG, % = ?11.2 + 3.16 (prepartum body condition) + 0.0009176 (MYP) (R² = 0.36, P < 0.05). Logistic regression indicated that Holstein × Carora crossbred cows tended to have 27% higher relative risk than Holstein to experience SCK, whereas prepartum liver TAG greater than 3% tended to be associated with a higher relative risk for SCK compared to cows with TAG ?3%. PMID:23738138

Gonzalez, Clara I.

2013-01-01

303

Biostratigraphic sequence analysis of Oligocene-Lower Miocene sections in the Orocual Field, Eastern Venezuela Basin  

SciTech Connect

A detailed biostratigraphic study of the Oligocene-Miocene boundary was carried out in sections 1000 ft thick of ten wells of the Orocual Field, Eastern Venezuela, The sequences under investigation carry a rich microfauna of benthic and planktonic foraminifera and calcareous nannoplankton. About 500 samples were analyzed and nearly 150 species of foraminifera and 60 of nannoplankton calcareous were identified. The planktonic assemblages allow the identification of zones N3 and N4 of Blow, 1969; zones NP23, NP24, NP25 and NN1 of Martini, 1971; and zones F and E of Stainforth et al., 1959 of the Carapita Formation. The paleoenvironments of these sediments were determined rather precisely and vary from inner shelf to middle slope. Paleobathymetric curves of several wells are included. High and low fossil abundance and diversity peaks were used to recognize two sequences of the third order and five of the fourth order between 24.8 Ma and 26.5 Ma. A generalized transgressive trend is evident from the Late Oligocene to the Early Miocene.

Giffuni, G.; Castro-Mora, M. [Departamento de Geologia, Lagoven, S.A., Caracas (Venezuela)

1996-08-01

304

[Trichogramma species (Hymenoptera: Trichogrammatidae) parasitoids of Lepidopteran eggs in Lara State, Venezuela].  

PubMed

This work was conducted to determine the occurrence of Trichogramma wasp species in Lara State, Venezuela. Lepidopteran egg samples collected from various crop leaves were observed daily under laboratory conditions for emergence of Trichogramma species adult wasps. Trichogramma were also obtained from traps containing eggs from the hosts Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) and Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). In the laboratory, specimens of Trichogramma species were mounted on microscope slides to show male genitalia and other morphological characters used for its identification. Trichogramma atopovirilia Oatman y Platner emerged from S. frugiperda eggs collected in a cornfield at La Palomera, Humocaro Alto and at El Parchal, Humocaro Bajo, Municipio Morán. T. atopovirilia also emerged from S. frugiperda eggs collected in a cornfield at Sabana Grande and from S. cerealella eggs used as traps in a pepper culture at Tintinal, Municipio Andrés Eloy Blanco. T. exiguum Pinto y Platner emerged from S. frugiperda eggs used as traps or collected in cornfield at Totumito and at La Palomera, Humocaro Alto. T. pretiosum Riley emerged from Phthorimaea operculella Zeller eggs collected on stored potatoes at Monte Carmelo, Sanare. The identification of Trichogramma species in Lara State would be useful in the development of biological control programs for lepidopteran pests. PMID:17934619

Morales, José; Vásquez, Carlos; Pérez B, Nieves L; Valera, Neicy; Ríos, Yolmar; Arrieche, Norayda; Querino, Ranyse B

2007-01-01

305

Evidence for high seroprevalence of Taenia solium cysticercosis in individuals from three rural communities in Venezuela.  

PubMed

A serological study was undertaken in 1998 to evaluate levels of Taenia solium cysticercosis in 3 rural Venezuelan communities. Infection with viable metacestodes was diagnosed with a trapping enzyme-linked immunosorbent assay (ELISA) that detects a secreted product of viable parasites. Anti-metacestode antibodies were assayed by ELISA using T. solium vesicular fluid as antigen. A total of 1254 sera was collected from 3 communities (Canoabo, Sanare, and Rio Tocuyo) where previous studies had suggested the presence of T. solium. Our results demonstrate an unusually high seroprevalence of cysticercosis, indicating an attendant risk of transmitting the disease to other areas. The seroprevalence of infection with viable cysts, as indicated by detection of circulating parasite antigen, was 9.1% in Canoabo, 6.1% in Sanare, and 5.7% in Rio Tocuyo. The corresponding frequency of antibodies to T. solium cyst antigens was 36.5% in Canoabo, 36.5% in Sanare, and 4% in Rio Tocuyo. As these communities are probably representative of many others in Venezuela, T. solium cysticercosis may be a significant public health problem and more work is certainly indicated. An important finding was that local knowledge of the disease and its transmission do not necessarily guarantee diminished disease prevalence, indicating a lack of appropriate vigilance towards disease control. PMID:15307416

Ferrer, Elizabeth; Cabrera, Zully; Rojas, Glenda; Lares, Maria; Vera, Andez; de Noya, Belkis Alarcon; Fernandez, Iris; Romero, Haidee Urdaneta; Harrison, Leslie J S; Parkhouse, R Michael E; Cortez, Milagros M

2003-01-01

306

[Food consumption patterns of children 4 to 14 years old in Valencia, Venezuela].  

PubMed

Results from a nutritional assessment are presented to establish the usual food consumption pattern of 438 children between 4-14 years of age, from a low income urban community in Valencia, Venezuela. Food intake data were collected through multiple 24 hours recalls and converted to individual food item weight in grams. Amounts of energy, macronutrients, iron, calcium, vitamin A, and vitamin C were estimated to compare them to national references. The food pattern was established according to intake frequency per food item and per food groups. Arepa was the most commonly consumed food item, and a main source of kilocalories, protein, carbohydrates, iron, and vitamin A. Unlike coffee, fruits were not among the most commonly consumed foods. Black beans were the main source of protein. Cookies and sodas were among the major sources of energy. Energy and nutrient intake were adequate, except for calcium (67% in preschoolers y 43% in school-aged children). Preschoolers' diet showed a better adequacy for all nutrients (p < 0.005), except for iron which was significantly higher in school-aged children. Since children below 15 years old are still forming food behaviors and habits, they are an ideal group to develop nutritional education strategies to modify harmful patterns such as high intake of sodas, and low intakes of calcium rich foods. PMID:16454054

del Real, Sara Irene; Fajardo, Zuleida; Solano, Liseti; Concepción Páez, María; Sánchez, Armando

2005-09-01

307

Variation of the vectorial capacity of some anophelines in western Venezuela.  

PubMed

The vectorial capacities of Anopheles nuneztovari, An. albitarsis s.l., and An. triannulatus to transmit Plasmodium vivax in western Venezuela were estimated in different seasons. In general, there was a decrease in the vectorial capacities of the three species during the dry season, which seems to be due mainly to a reduction in the mosquito biting populations. Comparing the observations made during the two wet seasons, there was a decrease in the vectorial capacities of the three species due to different factors for each species. In An. nuneztovari, the reduction in vectorial capacity seems to be due to a reduction in the human blood index (HBI); in An. albitarsis, it is probably due to a reduction in the HBI and a slight reduction in parity, whereas in An. triannulatus, the cause is probably a reduction in the mosquito biting population and in parity. The overall reduction in vectorial capacities of the three anopheline species in 1989 compared with the vectorial capacities in 1988 could partly explain the marked reduction in prevalence from 46.2 per 1,000 population in 1988 to 7.5 per 1,000 population in 1989. PMID:8166348

Rubio-Palis, Y

1994-04-01

308

The Fused Anthranilate Synthase from Streptomyces venezuelae Functions as a Monomer  

PubMed Central

Recently we showed that the fused chorismate-utilizing enzyme from the antibiotic-producing soil bacterium Streptomyces venezuelae is an anthranilate synthase (designated SvAS), not a 2-amino-2-deoxyisochorismate (ADIC) synthase, as was predicted based on its amino acid sequence similarity to the phenazine biosynthetic enzyme PhzE (an ADIC synthase). Here we report the characterization of SvAS using steady-state kinetics, gel filtration chromatography and laser light scattering. The recombinant His-tagged enzyme has Michaelis constants Km with respect to substrates chorismate and glutamine of 8.2 ± 0.2 ?M and 0.84 ± 0.05 mM, respectively, and a catalytic rate constant kcat of 0.57 ± 0.02 s?1 at 30°C. Unlike most other anthranilate synthases, SvAS does not utilize ammonia as a substrate. The enzyme is competitively but noncooperatively inhibited by tryptophan (Ki = 11.1 ± 0.1 ?M) and is active as a monomer. The finding that SvAS is a monomer jibes with the variety of association modes that have been observed for anthranilate synthases from different microorganisms, and it identifies the enzyme’s minimal functional unit as a single TrpE-TrpG pair. PMID:25355158

Ashenafi, Meseret; Reddy, Prasad T.; Parsons, James F.; Byrnes, W. Malcolm

2015-01-01

309

[Community structure of fishes on the east coast of the island of Cabagua, Venezuela].  

PubMed

The community structure of fishes on a sandy beach with patch of Thalassia and coral reefs was studied at Punta Las Cabeceras, Cubagua Island, Venezuela. Diurnal monthly samples were obtained from March 1999 to February 2000. Numerical abundance of fish species was recorded to determine the specific diversity. A total of 1 268 individual from 38 species and 20 families were identified: Haemulidae, Scaridae and Gerreidae were the more abundant, with 7, 4 and 3 species, respectively. Nicholsina usta, Eucinostomus argenteus, Halichoeres bivittatus and Tylosurus crocodiles made up 74.38% of the abundance, and present in 50% of the samples. The number of species occasional visitors was 30 (78.94%), indicative of the mobilization from another areas. On a monthly basis, the species number varied between 2 and 12; diversity index between 0.98 and 2.93 bits ind(-1), equitability (J') from 0.44 to 0.98, both indices showing the same tendency. N. usta and E. argenteus had the highest biological index equivalent to 59.1 and 60.0%, respectably, of the maximum possible total and were dominants and characteristics fishes of the community. PMID:15264572

Parra, Berta; Ruiz, Lilia J

2003-06-01

310

Resistance to malathion and deltamethrin in Aedes aegypti (Diptera: Culicidae) from western Venezuela.  

PubMed

Resistance to the insecticides deltamethrin and malathion and the enzymes associated with metabolic resistance mechanisms were determined in four field populations of Aedes aegypti (L.) from western Venezuela during 2008 and 2010 using the bottle assay and the microplate biochemical techniques. For deltamethrin, mortality rates after 1 h exposure and after a 24-h recovery period were determined to calculate the 50% knock-downconcentration (KC50) and the lethal concentration (LC50), respectively. For malathion, mortality was recorded at 24 h to determine the LC50. For deltamethrin, resistance ratios of knock-down resistance and postrecovery were determined by calculating the RRKC50 and RRLC50, comparing the KC50 and LC50 values of the field populations and those of the susceptible New Orleans strain. Knock-down resistance to deltamethrin was moderate in the majority of the populations in 2008 (RRKC50 values were between 5- and 10-fold), and only one population showed high resistance in 2010 (RRKC50 > 10-fold). Moderate and high postrecovery resistance to deltamethrin was observed in the majority of the populations for 2008 and 2010, respectively. There was significantly increased expression of glutathione-S-tranferases and mixed-function oxidases. All populations showed low resistance to malathion in 2008 and 2010 with significantly higher levels of alpha-esterases for 2008 and 2010 and beta-esterases for 2008. PMID:24180108

Alvarez, Leslie C; Ponce, Gustavo; Oviedo, Milagros; Lopez, Beatriz; Flores, Adriana E

2013-09-01

311

Tectonic implications of Paleocene-Eocene Foreland Basin, Lake Maracaibo, Venezuela  

SciTech Connect

A compilation of industry geological and geophysical data indicates that Paleocene-Eocene clastic sedimentation in the Maracaibo basin records the first manifestation of Cenozoic foreland basin tectonics in northern South America. Isopach maps based on industry seismic data and well logs suggest that the Maracaibo foreland basin formed a 100 to 200 km wide elongate trough along the northeastern edge of the present-day Lake Maracaibo. The basin is asymmetric with a deep (7 km) northeastern margin adjacent to an exposed southwest-verging thrust belt mapped by previous workers. Isopach mapping of seven seismic units within the Eocene suggest a nor-northwest to southeast migration of the depocenter from Paleocene to Middle Eocene time at a rate of 0.6 cm/year. A similar style of foreland basin has been previously identified over a distance of 1000 Km from western central Venezuela to Trinidad. Eocene to Pliocene ages of foreland basin sedimentation in these areas suggest time transgressive, oblique collision of the Caribbean plate along the northern margin of South America. Comparison of the age of deformation along both the northern and southern edges of the pro-Caribbean plate yield reasonable estimates for the rate of relative motion of this small plate relative to the larger America plates.

Lugo, J. (Lagoven S.A., Caracas (Venezuela)); Mann, P. (Univ. of Texas, Austin (United States))

1993-02-01

312

A new rabbit species (Sylvilagus, Mammalia: Leporidae) from the lowlands of Venezuela.  

PubMed

A new species of Venezuelan rabbit of the genus Sylvilagus from Fundo Millano (08 degrees 46'N and 69 degrees 56'W) and Chorrosco Bajo (08 degrees 05'N and 69 degrees 18'W), between 190 and 120 masl, state of Barinas, is described based on: 1. Body and skull measurements. 2. Coloration patterns of the pelage. 3. Arrangement and length of the color hair bands of dorsal, lateral, ventral nuchal, and gular patches. Body and cranial measurements, and some color patterns of the new species, Sylvilagus varynaensis, were compared with those of the closest relative groups such as S. brasiliensis (from Venezuela and Brazil), S. b. meridensis from the Venezuelan paramos, and three of the most representative groups of S. floridanus (S. f. continentis, S. f. orinoci, and S. f. valenciae). Most of the values recorded for these parameters were significantly higher for the new species (P < 0.005; Student "t" test). Cluster and principal components analysis of the data recorded for cranial characteristics indicated that S. varynaensis is the largest and darkest of the known Venezuelan rabbits, with a broader elongated skull and a different arrangement of the color hair bands. PMID:11795167

Durant, P; Guevara, M A

2001-03-01

313

Comparative study of the chemical composition of essential oils of five Tagetes species collected in Venezuela.  

PubMed

The leaves and inflorescences of five species of Tagetes, family Asteraceae, were collected from different locations in Mérida state, Venezuela, and their essential oils analyzed by GC and GC/MS. Several differences were observed in the composition of these oils, mainly regarding the major components, which for T. caracasana were trans-ocimenone (64.3%) and cis-tagetone (13.7%), and for T. erecta, piperitone (35.9%) and terpinolene (22.2%). High amounts of trans-anethole (87.5%) and estragole (10.7%) were observed in T. filifolia, while T. subulata essential oil contained terpinolene (26.0%), piperitenone (13.1%) and limonene (10.8%). For T. patula, two different oil samples were analyzed, leaves (TPL) and inflorescences (TPI). The TPL oil showed terpinolene (20.9%) and piperitenone (14.0%) as main components, while the TPI sample was composed mainly of beta-caryophyllene (23.7%), terpinolene (15.6%) and cis-beta-ocimene (15.5%). PMID:23074915

Armas, Kaylin; Rojas, Janne; Rojas, Luis; Morales, Antonio

2012-09-01

314

Epidemiological survey of histoplasmine and paracoccidioidine skin reactivity in an agricultural area in Bolívar state, Venezuela.  

PubMed

Paracoccidiodomycosis and histoplasmosis are endemic diseases in the south of Venezuela, representing a public health problem. Prevalence of Paracoccidiodes brasiliensis and Histoplasma capsulatum infections were estimated in Monte Ralo, a rural community area of Bolivar state using paracoccidiodine and histoplasmine skin tests. Paracoccidiodine was intradermically injected to 173 persons and readings were made at 24 and 48 h afterwards to 167 persons (97.85%). Reaction was positive in 8.5% (n = 14) at 24 h post-injection and 13.2% (n = 20) at 48 h. Farmers showed the higher percentage of positivity at 24 and 48 h. One hundred-seventy five persons were intradermically injected with histoplasmine but 167 and 157 of them attended for reading of the dermal reaction at 24 and 48 h post-injection respectively. Tests were positive in 25.7% (n = 43) at 24 h and 42.7% (n = 67) at 48 h. Further studies are needed in surrounding places to delimit the endemic area of these mycosis in the Bolivar state. However, epidemiological vigilance of PCM and H should be considered by local health authorities. PMID:15074575

Cermeño, Julman Rosiris; Hernández, Isabel; Cermeño, Julmery Jesús; Godoy, Gerardo; Cermeño, July Josefina; Orellán, Yida; Blanco, Ytalia; Cabello, Ismery; Guzmán, Yesenia; Alcalá, Frannelly; García, Teófilo; Penna, Salvador

2004-01-01

315

Mechanisms of Oryza sativa (Poaceae) resistance to Tagosodes orizicolus (Homoptera: Delphacidae) under greenhouse condition in Venezuela.  

PubMed

Tagosodes orizicolus is one of the main plagues of rice in tropical America causing two types of damages, the direct one, feeding and oviposition effect, and an indirect one, by the transmission of the "Rice hoja blanca virus". During 2006-2007 we carried out research under greenhouse conditions at Fundaci6n Danac, Venezuela, in order to determine the mechanisms of antixenosis, antibiosis and tolerance to T. orizicolus, which could be acting in commercial varieties and advanced lines of the rice genetic breeding programs of INIA and Fundaci6n Danac. The method of free feeding was used for the antixenosis evaluation, whereas the method of forced feeding was used for antibiosis evaluation (effect on survival and oviposition). Additionally, we used the indirect method based on biomass depression to estimate the tolerance. Some of the evaluated traits included: grade of damage, number of insects settling on rice plants, percentage of sogata mortality at the mature state, number of eggs in the leaf midrib and an index of tolerance. The results showed that rice genotypes possess different combinations of resistance mechanisms, as well as different grades of reactions. The susceptible control 'Bluebonnet 50' was consistently susceptible across experiments and the resistant control 'Makalioka' had high antixenosis and high antibiosis based on survival and oviposition. The rest of the genotypes presented lower or higher degrees of antixenosis and antibiosis for survival and oviposition. The genotype 'FD0241-M-17-6-1-1-1-1' was identified with possible tolerance to the direct damage of sogata. PMID:22458212

González, Alex; Labrín, Natalia; Alvarez, Rosa M; Jayaro, Yorman; Gamboa, Carlos; Reyes, Edicta; Barrientos, Venancio

2012-03-01

316

Asymmetrical and heterogeneous elasto-static deformation along the El Pilar Fault in Northeastern Venezuela  

NASA Astrophysics Data System (ADS)

Velocities field in both sides of the El Pilar fault, the most important right-lateral strike-slip fault of the Caribbean-South America plate boundary, present an important asymmetry. This pattern suggests a change in elastic properties when crossing the fault. We have applied an asymmetric model to simulate observed velocities with 20 mm/yr creep at depth, corresponding at the relative velocity of Caribbean plate versus South America plate. The preferred model indicated a shallow locking depth at 4.5 km. In a second part, a near-fault low-rigidity compliant zone from 3 km of depth with a 30 per cent of rigidity reduction respect to the environment is proposed using a 3D elasto-static model. We use GPS data from 23 stations collected in 2002 and 2005 like input parameters as well as geometry parameters based in previous work. The shallow locking depth and the interseismic velocities used in the asymmetry and compliant zone models respectively support: i) the hypothesis of a partially locked seismogenic upper part, ii) the concentration of the Caribbean- South America relative displacement entirely along the El Pilar Fault. Reinoza Carlos PhD thesis and stay in ISTerre Laboratory is funded through Venezuela's FUNDAYACUCHO Grant N° 756514C. This research is a contribution to FONACIT-ECOS Nord grant 2009000818 (French code V10U01). Observed velocities (white) from 2002 and 2005 GPS campaign measurements data with error ellipses drawn for 66% confidence level expressed in the South America plate reference frame.

Reinoza, C.; Jouanne, F.; Audemard, F. A.; Beck, C.

2013-05-01

317

Sources of ?15N variability in sinking particulate nitrogen in the Cariaco Basin, Venezuela  

NASA Astrophysics Data System (ADS)

Ten years of monthly observations of the ?15N of sinking particulate nitrogen (?15N-PN (in ‰ versus atmospheric N2)=[(15N/14N)sample/(15N/14N)standard)-1]1000) in the Cariaco Basin, Venezuela, confirm that the basin's bottom sediments store information about nitrogen dynamics related to seasonal and interannual variability in regional surface ocean processes. During the upwelling period of the southern Caribbean Sea (February-April), the ?15N-PN is similar to that of the thermocline nitrate (˜3.5‰). This nitrate is imported into the Cariaco Basin with Subtropical Underwater (SUW), which wells up near the coast. Thus, particles generated by phytoplankton photosynthesis during this productive period bear a sub-tropical North Atlantic isotopic imprint of N2 fixation (low compared to the global average of nitrate ?15N?5‰). During the non-upwelling period when surface waters are stratified (September-November), the ?15N-PN is also 3.5-4.0‰, and reflects a mixture of local N2 fixation within the mixed layer, inputs of terrigenous organic matter and SUW nitrate consumption by phytoplankton below the mixed layer, which most likely exerts the strongest control on the ?15N-PN signal during this time. In the transition periods of May-July and December-January, the ?15N-PN increases to 4.5-6.5‰. This coincides with maxima of continental material fluxes (terrestrial PON ?15N is >6‰) into the Cariaco Basin. The ?15N signal in the sediments of the Cariaco Basin thus provides information about the relative strength of the local coastal upwelling, the relative input of continental material via river runoff, and local N2 fixation. The findings contribute to interpretations of the basin's paleoclimatic nitrogen cycle variations based on observations of the sedimentary ?15N record at this location.

Montes, Enrique; Thunell, Robert; Muller-Karger, Frank E.; Lorenzoni, Laura; Tappa, Eric; Troccoli, Luis; Astor, Yrene; Varela, Ramón

2013-09-01

318

[Pesticide residues in drinking water of an agricultural community in the state of Mérida, Venezuela].  

PubMed

The aim of this study was to determine the presence of pesticides in drinking water from six aqueducts in a region of intense agricultural activity in the state of Merida, Venezuela. The study was conducted for four continuous weeks, between May and June 2008. Pesticide residues were analyzed by solid phase extraction (SPE) and liquid chromatography (HPLC) with diode array detector (DAD). The method SPE-HPLC-DAD met the criteria of analytical validation, with good linearity (R2: 0.9840 to 0.9999), precision (coefficient of inter-day variability from 1.47 to 6.25%), accuracy (relative standard deviation 0.9 to 9.20%) and sensitivity (LOD < or = 0.012 microg/L; LOQ < or = 0.030 microg/L, except mancozeb with 0.400 microg/L). Seven of the thirteen selected pesticides have a recovery rate between 100% and 70%, the rest between 61% and 37%. Ten pesticides of the following chemical groups, were detected in 72 samples analyzed: organophosphates, carbamates, triazines and urea derivatives. The pesticides with the highest frequency of detection were: carbofuran and atrazine (39%), malathion (25%), dimethoate and metribuzin (19%). The pesticides found at high levels were diazinon (26.31 microg/L), methamidophos (10.99 microg/L), malathion (2.03 microg/L) and mancozeb (1.27 microg/L). Pesticide levels did not exceed the maximum allowed by Venezuelan law, however, according to international standards (EU and EPA-USA) values were above the maximum permissible levels. This study demonstrates the urgent need for systematic monitoring of the quality of water for human consumption in regions of high agricultural productivity. PMID:22523840

Flores-García, Mery Elisa; Molina-Morales, Yuri; Balza-Quintero, Alirio; Benítez-Díaz, Pedro Rafael; Miranda-Contreras, Leticia

2011-12-01

319

Ecoepidemiological and Social Factors Related to Rabies Incidence in Venezuela during 2002-2004  

PubMed Central

Rabies in Venezuela has been important in last years, affecting dogs, cats, and human, among other animals, being a reportable disease. In Zulia state, it is considered a major public health concern. Recently, a considerable increase in the incidence of rabies has been occurring, involving many epidemiological but also ecoepidemiological and social factors. These factors are analyzed in this report. During 2002-2004, 416 rabies cases were recorded. Incidence has been increasingly significantly, affecting mainly dogs (88.94%). Given this epidemiology we associated ecoepidemiological and social factors with rabies incidence in the most affected state, Zulia. In this period 411 rabies cases were recorded. Zulia has varied environmental conditions. It is composed mostly of lowlands bordered in the west by mountain system and in the south by the Andes. The mean is temperature 27.8°C, and mean yearly rainfall is 750 mm. Climatologically, 2002 corresponded with El Niño (drought), middle 2003 evolved to a Neutral period, and 2004 corresponded to La Niña (rainy); this change may have affected many diseases, including rabies. Ecological analysis showed that most cases occurred in lowland area of the state and during rainy season (p<0.05). Additionally, there is an important social problem due to educational deficiencies in the native population. Many ethnic groups live un Zulia, many myths about rabies are in circulation, and the importance of the disease is not widely realized. The full scale of the rabies burden is unknown, owing to inadequate disease surveillance. Although there have been important advances in our knowledge and ability to diagnose and prevent it, enormous challenges remain in animal rabies control and provision of accessible-appropriate human prophylaxis worldwide. Human and animal surveillance including ecological and social factors is needed. PMID:23674960

Rifakis, Pedro M.; Benitez, Jesus A.; Rodriguez-Morales, Alfonso J.; Dickson, Sonia M.; De-La-Paz-Pineda, Jose

2006-01-01

320

Cenozoic transpressional model for the tectonic and basinal development of Venezuela and Trinidad  

SciTech Connect

Geological features and plate tectonic constraints are integrated to outline a revised model for the Jurassic to Recent development of northern South America east of Guajira Peninsula. Development appears controlled by NoAm/SoAm and Carib/SoAm relative motions. Main phases were: (1) Jurassic rifting; (2) Late Jurassic - Maestrichtian passive margin sedimentation; (3) Eocene-Recent north-vergent understanding of Proto-Caribbean (Atlantic) crust beneath Venezuela; (4) eastwardly progressive Cenozoic south-vergent dextral transpression between northern South America and the Pacific-derived Caribbean Plate, and obduction of Caribbean terranes onto SoAm; (5) Neogene-Recent north-vergent underthrusting of Caribbean crust beneath the Guajira, Paraguana, and ABC (Aruba-Bonaire-Curacao-Orchila) terranes. Compressional and transcurrent sedimentary basins were developed in Cenozoic time in response to Carib-SoAm relative motion and terrane obduction, above rocks of the pre-existing Jurassic-Cretaceous passive shelf. Although Jurassic rift-related petroleum source rocks may have been deposited locally, primary source rocks are Upper Cretaceous and were deposited well after Jurassic rifting such that they were not affected by rift-related heat. In the absence of Cretaceous volcanism, geothermal gradients may be assumed to have been fairly normal. Maturation was thus a function of depth of burial, which was insufficient in each basin until Cenozoic basin development. A second phase of rapid deposition and hence maturation of Neogene age has occurred in inter-Andean basins of the west (e.g., Maracaibo) due to Miocene uplift and erosion of Andean ranges. These predicted maturation times are corroborated by more direct studies.

Pindell, J.L. (Dartmouth College, Hanover, NH (United States)); Dewey, J.F. (Oxford Univ. (United Kingdom))

1991-03-01

321

Chronostratigraphy of the Cretaceous-Oligocene unconformity in Northern Monagas, Eastern Venezuela  

SciTech Connect

Palynological analyses of several subsurface sections in the autochthonous block in Northern Monagas, eastern Venezuela, show a Cretaceous-Oligocene unconformity. The Maastrichtian to Paleocene sandstones of the San Juan Formation unconformably underlie the Oligocene to Miocene sandstones of the Merecure Formation. Log analyses indicate two stratigraphic sequences within San Juan and two more within Merecure, and integration with paleontological data indicates changes which can be correlated with Haq et al.'s (1988) Sequence Chronostratigraphic Charts as follows: (1) The basal San Juan sandstones represent the late Maastrichtian (68 Ma) drop of seal level and the UZA-4.5/TA-1.1 Sequence Boundary (SB). The Maastrichtian or Maastrichtian to Paleocene San Juan sandstones represent either the TA-1.1 and the TA-1.2 Third-Order Cycles. (2) The late Oligocene sequence overlying the unconformity, represents the TB-1.3 Cycle starting at 26.5 Ma. Within this lower part of the Merecure sediments, an increase in the abundance and diversity of marine palynomorphs represents a maximum transgression correlatable with the 26 Ma Condensed Section contained in the Tb-1.3 Cycle. (3) The upper part of Merecure represents the Tb-1.4 Cycle starting at 25.5 Ma. Within this cycle, the lowermost (Oligocene) sandstones contain almost exclusively terrestrial palynomorphs, while the (Miocene) alternating sands and shales of the upper part contain diverse marine palynomorphs indicating a change from Low Stand Wedge to Transgressive deposits. This change is correlated with the Oligocene/Miocene limit at 25.2 Ma.

Helenes, J. (Corpoven S.A., Puerto La Cruz (Venezuela))

1993-02-01

322

Leaping behavior of Pithecia pithecia and Chiropotes satanas in eastern Venezuela.  

PubMed

I observed leaping behavior in the white-faced saki (Pithecia pithecia) and the black-bearded saki (Chiropotes satanas satanas) for 15 and 10 months, respectively, as part of a larger study of positional behavior in the tribe Pitheciini. I used focal animal instantaneous sampling to observe the two species on separate islands in their natural habitat at Guri Lake, Venezuela. Leaping behavior correlates with patterns of forest use and body size, and differences between the species relate more to habitat preferences than to habitat differences per se. Pithecia usually chose vertical or highly angled supports of lower tree portions for take-off and landing, and took off from a stationary posture. Chiropotes took off from the main crown or terminal branches, gaining momentum from locomotor movement before performing a leaping take-off. Pithecia's vertical body orientation and longer leap distance allowed it to assume a mid-flight tuck to prepare for a hindlimb-first landing onto a solid support, and to absorb landing forces with its relatively longer hindlimbs. Chiropotes remained more pronograde throughout its leaps, and minimized landing forces by landing on all four limbs onto numerous flexible supports in the terminal branches. The smaller-bodied P. pithecia is specialized for vertical clinging and leaping, and exhibits behavioral and morphological parallels with other vertical clingers and leapers. The larger C. satanas is a generalized leaper that lacks morphological specializations for leaping. Pithecia's use of solid supports in the lower tree portions allows it to move quietly through the forest-one of a suite of behaviors related to predator avoidance. This example of variation within one behavioral category has implications for devising locomotor classifications and interpreting fossil remains. PMID:16104032

Walker, Suzanne E

2005-08-01

323

Importance of the horse and financial impact of equine trypanosomiasis on cattle raising in Venezuela.  

PubMed

In Venezuela, horses are indispensable for extensive cattle raising, and extensive cattle raising prevails in all regions. This determines the numerical relationship between horses and cattle (r?=?0.93) to be relatively constant nationwide. At regional level, the average extension of cattle ranches varies greatly. However, in relation to the area covered by pastures, the numbers of horses (r?=?0.95) and cattle (r?=?0.93) are relatively uniform nationwide. Water buffalo occupy small fractions of the territory; therefore, their numbers are related to the area of pastures less strongly (r?=?0.56). There is no information on the numerical relationship between the numbers of horses and water buffalo. In the Llanos region of the country, equine trypanosomiasis is responsible for a high mortality in horses, causing considerable financial losses to cattle ranches. So far, such losses have not been assessed. For this region, in 2008, it can be calculated that: (1) with no treatment, losses owing to horse mortality caused by this hemoparasitosis would have amounted to US$7,486,000; (2) the diagnosis and treatment of affected horses would have required an investment of US$805,000; and (3) in terms of horses saved, this investment would have resulted in benefit of US$6,232,000. Therefore, for every monetary unit invested, there would be a benefit 7.75 times greater, this ratio being applicable to any year and all regions of the country. It follows that the profitability of investing in the diagnosis and treatment of equine trypanosomiasis is guaranteed. PMID:23666515

Moreno, S Andrea; Concepción, Juan Luis; Nava, Mayerly; Molinari, Jesús

2013-11-01

324

[Reproductive activity of Chelonia mydas (Testudines: Cheloniidae) in Isla de Aves, Venezuela (2001-2008)].  

PubMed

The second major nesting-site for green turtles in the Caribbean is Isla de Aves, an island protected as a wildlife refuge since 1972, located at 650km Northeast from La Guaira, Venezuela. In this island, the nesting population monitoring started in 1972 and in a more continuous way after 1978, when a Scientific-Naval Station was established and scientific observations started. Since historical data show that female captures had severely affected population levels in this island before 1978, this study aim to describe recent reproductive activities. For this, during the nesting seasons of 2001-2002 and 2005-2008, nesting females were measured and tagged using metal flipper tags. A total of 458 nights were sampled observing 5 154 female emergences, with a maximum of 53 in a single night. Non-observed emergences were calculated fitting the temporal distribution of observed emergences to a normal curve. Total emergences estimated varied from X=637.1+/-106.6 in 2001 to X =2 853+/-42.5 in 2008 (ANOVA F(6.5df)=60.37, p<0.0001). Internesting interval in the same season was estimated in X=10.71+/-1.32 days. Clutch frequency in a nesting season was calculated as X=1.71+/-1.6 times per female and season. Estimated number of nesting females per year varied from X=373+/-12.5 females in 2001 to X=l 669+/-56.1 females in 2008 (ANOVA F 55.6df)=89.42, p<0.0001); with a positive and significant trend (r=0.842, p=0.036). Results show that nesting females numbers are increasing. We suggest that the protection of the nesting area for more than 30 years, has contributed with this population increase. PMID:23894943

Vera, Vicente; Buitrago, Joaquín

2012-06-01

325

Politics, class actors, and health sector reform in Brazil and Venezuela.  

PubMed

Universal access to healthcare has assumed renewed importance in global health discourse, along with a focus on strengthening health systems. These developments are taking place in the backdrop of concerted efforts to advocate moving away from vertical, disease-based approaches to tackling health problems. While this approach to addressing public health problems is a step in the right direction, there is still insufficient emphasis on understanding the socio-political context of health systems. Reforms to strengthen health systems and achieve universal access to healthcare should be cognizant of the importance of the socio-political context, especially state-society relations. That context determines the nature and trajectory of reforms promoting universality or any pro-equity change. Brazil and Venezuela in recent years have made progress in developing healthcare systems that aim to achieve universal access. These achievements are noteworthy given that, historically, both countries had a long tradition of healthcare systems which were highly privatized and geared towards access to healthcare for a small segment of the population while the majority was excluded. These achievements are also remarkable since they took place in an era of neoliberalism when many states, even those with universally-based healthcare systems, were moving in the opposite direction. We analyze the socio-political context in each of these countries and look specifically at how the changing state-society relations resulted in health being constitutionally recognized as a social right. We describe the challenges that each faced in developing and implementing healthcare systems embracing universality. Our contention is that achieving the principle of universality in healthcare systems is less of a technical matter and more a political project. It involves opposition from the socially conservative elements in the society. Navigation to achieve this goal requires a political strategy that involves various actors within the state, the political society and civil society. PMID:23563780

Mahmood, Qamar; Muntaner, Carles

2013-03-01

326

[Bats (Chiroptera: Mammalia) from Yurubí National Park, Venezuela: taxonomic list and community study].  

PubMed

Bats represent a key component in the dynamics of many terrestrial ecosystems, and one of the groups of mammals with the highest levels of diversification in the Neotropics. Here we describe the results of a study of the bat fauna from Yurubí National Park (mountain area in Northern Venezuela), that includes a taxonomic list and the characterization of some community attributes in forested areas. Data was collected from zoological collections and diversified sampling methods from February to July of 2009 in an altitudinal gradient (100-1 500m), with three principal ecological units: semideciduous, evergreen and cloud forests. We recorded 64 species grouped in five families (63% of the bats known from La Cordillera de la Costa), of which Phyllostomidae was the dominant taxa (42 species; 66% of total), followed by Vespertilionidae, Molossidae, Emballonuridae and Mormoopidae. The community with the highest taxonomic diversification was found in the lowest elevation range, while the lowest number of species was found at the highest range. Eleven trophic guilds were identified; the insectivorous guild was the richest, whereas the frugivorous was the most abundant. Our results allow us to indicate these forest ecosystems have an appropriate conservation status, taking into account the presence of a relatively high proportion of species from the subfamily Phyllostominae, as well as the presence of other species with conservation priorities. All these aspects, and the fact that this represents a reservoir of the biological diversity of the forest ecosystems of La Cordillera de la Costa, make this protected area of an essential conservation value, in a highly endangered bioregion by neighboring socio-economic growth. PMID:22208091

Delgado-Jaramillo, Mariana; Machado, Marjorie; García, Franger J; Ochoa, José

2011-12-01

327

Lithospheric expression of cenozoic subduction, mesozoic rifting and the Precambrian Shield in Venezuela  

NASA Astrophysics Data System (ADS)

We have combined surface wave tomography with Ps and Sp receiver-function images based on common-conversion-point (CCP) stacking to study the upper mantle velocity structure, particularly the lithosphere-asthenosphere boundary (LAB), beneath eastern and central Venezuela. Rayleigh phase velocities in the frequency range of 0.01-0.05 Hz (20-100 s in period) were measured using the two-plane-wave method and finite-frequency kernels, and then inverted on a 0.5° × 0.5° grid. The phase velocity dispersion data at grid points were inverted for 1D shear velocity profiles using initial crust-mantle velocity models constructed from previous studies. The 3D velocity model and receiver-function images were interpreted jointly to determine the depth of the LAB and other upper mantle features. The tomographic images revealed two high velocity anomalies extending to more than ?200 km depth. One corresponds to the top of the subducting Atlantic plate beneath the Serrania del Interior. The other anomaly is a highly localized feature beneath the Maturin Basin. The LAB depth varies significantly in the study region: It is located at ?110 km depth beneath the Guayana Shield, and reaches ?130 km at the northern edge of the Maturin Basin, which might be related to the downward flexural bending due to thrust loading of the Caribbean plate and pull from the subducting Atlantic plate. Immediately to the west, the lithosphere is thin (?50-60 km) along the NE-SW trending Espino Graben from the Cariaco basin to the Orinoco River at the northern edge of the craton. The LAB in this region is the top of a pronounced low velocity zone. Westward, the lithosphere deepens to ?80 km depth beneath the Barinas Apure Basin, and to ?90 km beneath the Neogene Merida Andes and Maracaibo block. Both upper mantle velocity structure and lithosphere thickness correlate well with surface geology and are consistent with northern South American tectonics.

Masy, Jeniffer; Niu, Fenglin; Levander, Alan; Schmitz, Michael

2015-01-01

328

Chagas’ Disease: An Emergent Urban Zoonosis. The Caracas Valley (Venezuela) as an Epidemiological Model  

PubMed Central

The unprecedented emergence of important public health and veterinary zoonoses is usually a result of exponential population growth and globalization of human activities. I characterized Chagas’ disease as an emergent zoonosis in the Caracas Valley (Venezuela) due to the following findings: the presence of reservoirs (Didelphis marsupialis, Rattus rattus) and vectors (Panstrongylus geniculatus, Panstrongylus rufotuberculatus) infected with Trypanosoma cruzi in urbanized or marginalized areas; the elevated contact between P. geniculatus and human beings detected by parasitological and molecular examinations of triatomine feces demonstrated the possibility of transmission risks; a study of outbreaks of urban Chagas’ disease reported the first proven case of oral transmission of T. cruzi to human beings; the risk of transmission of glandular metacyclic stages from marsupials by experimental ocular and oral instillation; mice genitalia infected with T. cruzi contaminated blood resulted in the formation of amastigotes very close to the lumen suggesting that there may be a possibility of infection via their release into the urine and thence to the exterior; the ubiquitous histotropism and histopathology of T. cruzi was demonstrated using a mouse model; the presence of experimental T. cruzi pseudocysts in adipose, bone-cartilage, and eye tissue indicated a potential risk for transplants. Socio-sanitary programs that include improvements in housing, vector control, and access to medical treatment, as well as strategies aimed at combating social inequalities, poverty, and underdevelopment should be undertaken in those areas where zoonoses are most prevalent. Disciplines, such as Ecology, Epidemiology, Medical Entomology, Human and Veterinary Medicine, Environmental Studies, Public Health, Social and Political Studies, Immunology, Microbiology, and Pharmacology could all provide important contributions that aim to reduce the occurrence of factors governing the spread of emergent diseases. PMID:25520950

Urdaneta-Morales, Servio

2014-01-01

329

Spectral analysis of gravity anomalies and the architecture of tectonic wedging, NE Venezuela and Trinidad  

NASA Astrophysics Data System (ADS)

We have analyzed the spectral content of free air gravity anomalies in the Caribbean-South American plate boundary zone in order to determine better the near-surface (0-120 km) distribution of crustal and upper mantle elements which give rise to the unusual gravity field of this region. The plate boundary zone in northeastern Venezuela and Trinidad is the site of the world's sea level continental minimum of Bouguer gravity anomalies, yet the region is also one of mild topography (mean value 43 m, maximum 1200 m). We find the mean depths to interfaces of significant density contrast at a variety of depths for portions of the plate boundary zone. We interpret interfaces at 30-35 km and 32 km beneath the Guyana Shield and the Aves Ridge, respectively, to be the Moho. Other shallow interfaces (5-14 km) are most likely sediment cover-basement contacts in the Maturin foreland basin and southern Grenada Basin. Deeper interfaces (54-63 km) we associate with loaded and downwarped continental and oceanic South American lithosphere. The deepest boundaries, at depths of 89-120 km, may be related to detached or detaching oceanic lithosphere overridden by continental South America. We use our results to test the tectonic wedging model of the plate boundary zone recently published by Russo and Speed (1992). We find that the tectonic wedging model adequately describes many of the structural boundaries inferable from our analysis of gravity anomalies but that the model must be modified to include a thinner Guyana Shield crust.

Russo, R. M.; Speed, R. C.

1994-06-01

330

Non-capsulated and capsulated Haemophilus influenzae in children with acute otitis media in Venezuela: a prospective epidemiological study  

PubMed Central

Background Non-typeable Haemophilus influenzae (NTHi) and Streptococcus pneumoniae are major causes of bacterial acute otitis media (AOM). Data regarding AOM are limited in Latin America. This is the first active surveillance in a private setting in Venezuela to characterize the bacterial etiology of AOM in children < 5 years of age. Methods Between December 2008 and December 2009, 91 AOM episodes (including sporadic, recurrent and treatment failures) were studied in 87 children enrolled into a medical center in Caracas, Venezuela. Middle ear fluid samples were collected either by tympanocentesis or spontaneous otorrhea swab sampling method. Standard laboratory and microbiological techniques were used to identify bacteria and test for antimicrobial resistance. The results were interpreted according to Clinical Laboratory Standards Institute (CLSI) 2009 for non-meningitis isolates. All statistical analyses were performed using SAS 9.1 and Microsoft Excel (for graphical purposes). Results Overall, bacteria were cultured from 69.2% (63 of the 91 episodes); at least one pathogen (S. pneumoniae, H. influenzae, S. pyogenes or M. catarrhalis) was cultured from 65.9% (60/91) of episodes. H. influenzae (55.5%; 35/63 episodes) and S. pneumoniae (34.9%; 22/63 episodes) were the most frequently reported bacteria. Among H. influenzae isolates, 62.9% (22/35 episodes) were non-capsulated (NTHi) and 31.4% (11/35 episodes) were capsulated including types d, a, c and f, across all age groups. Low antibiotic resistance for H. influenzae was observed to amoxicillin/ampicillin (5.7%; 2/35 samples). NTHi was isolated in four of the six H. influenzae positive samples (66.7%) from recurrent episodes. Conclusions We found H. influenzae and S. pneumoniae to be the main pathogens causing AOM in Venezuela. Pneumococcal conjugate vaccines with efficacy against these bacterial pathogens may have the potential to maximize protection against AOM. PMID:22335965

2012-01-01

331

Geochronology of recent sediments from the Cariaco Trench (Venezuela) by Alpha Spectrometry of {sup 210}Pb ({sup 210}Po)  

SciTech Connect

210Pb concentration in marine sediments of the Cariaco Trench (North-East of Venezuela) was measured through the analysis of 210Po alpha emissions, which can be assumed to be in secular equilibrium with 210Pb. The analysed sediment core has a length of 1.9 m. The results allowed to apply the CF:CS dating model (Constant Flux and Constant Supply). The sedimentation rate was estimated to be 0.25 cm/y. As far as we know this is the first {alpha}- dating carried out in the country, performed with an alpha spectrometer recently funded by the IAEA.

Arriojas, A.; Barros, H.; Palacios, D.; Sajo-Bohus, L. [Laboratorio de Fisica Nuclear, Universidad Simon Bolivar, Caracas (Venezuela, Bolivarian Republic of); Hurtado, S.; Villa, M. [Centro de Investigacion, Tecnologia e Innovacion de la Universidad de Sevilla (Spain); Perez, K.; Alfonso, J. [Centro de Quimica, Instituto Venezolano de Investigaciones Cientificas (Venezuela, Bolivarian Republic of)

2010-08-04

332

A new species of small-eared shrew from Colombia and Venezuela (Mammalia: Soricomorpha: Soricidae: Genus Cryptotis)  

USGS Publications Warehouse

Populations of small-eared shrews inhabiting the northern Cordillera Oriental of Colombia and adjoining Venezuelan highlands in the vicinity of Paramo de Tama have been referred alternatively to Cryptotis thomssi or Cryptotis meridensis. Morphological and morphometrical study of this population indicates that it belongs to neither taxon, but represents a distinct, previously unrecognized species. I describe this new species as Cryptotis tamensis and redescribe C. meridensis. Recognition of the population at Paramo de Tama as a separate taxon calls into question the identities of populations of shrews currently represented only by single specimens from Cerro Pintado in the Sierra de Perija, Colombia, and near El Junquito in the coastal highlands of Venezuela.

Woodman, N.

2002-01-01

333

Universidad Simn Bolvar, Edif. Energtica, Planta Baja. Valle de Sartenejas, Baruta, Caracas, Edo. Miranda, Venezuela, 89000 Telef.: 58 212 906-3708 / 3709 / 3710 / 3711 Fax: 58 212 906-3712 www.ulab.usb.ve  

E-print Network

. Miranda, Venezuela, 89000 Telef.: 58 212 906-3708 / 3709 / 3710 / 3711 Fax: 58 212 906-3712 www siguiente: Universidad Simón Bolívar Valle de Sartenejas Baruta; Edo. Miranda, 1080 Venezuela Cód. Doc.: UL

Vásquez, Carlos

334

A new species of Caligus (Copepoda, Siphonostomatoida) from the plankton of the Caribbean coast of Venezuela with a key to species  

PubMed Central

Abstract During a survey of the zooplankton community of Bahía Amuay, Venezuelan Caribbean, specimens of an undescribed species of Caligus Müller were collected. It resembles Caligus xystercus Cressey and Caligus ocyurus Cressey, both known only from the Caribbean Sea. The new species can be distinguished from these and other congeners by a combination of characters including the armature of legs 1 and 4, but mainly by its unique female genital complex. This is the first species of Caligus described from Venezuela. The species is described in full and a key to the species of the genus recorded in Venezuela is provided. PMID:22768004

Suárez-Morales, Eduardo; Camisotti, Humberto; Martín, Alberto

2012-01-01

335

New insights into the tectonic evolution of the Boconó Fault, Mérida Andes, Venezuela  

NASA Astrophysics Data System (ADS)

The Boconó fault is a major right-lateral strike-slip fault that cuts along strike the Mérida Andes in Venezuela. The uplift of this mountain range started in the Miocene as a consequence of the relative oblique convergence between two lithospheric units named the Maracaibo block to the northwest and the Guyana shield to the southeast. Deformation in the Mérida Andes is partitioned between a strike-slip component along the Boconó fault and shortening perpendicular to the belt. Distinctive features define the Boconó fault: it is shifted southward relative to the chain axis and it does not have a continuous and linear trace but is composed of several fault segments of different orientations striking N35°E to N65°E. Quaternary fault strike-slip motion has been evidenced by various independent studies. However, onset of the strike-slip motion, fault offset and geometry at depth remains a matter of debate. Our work, based on morphostructural analyses of satellite and digital elevation model imagery, provides new data on both the geometry and the tectonic evolution of this major structure. We argue that the Boconó fault affects only the upper crust and connects at depth to a décollement. Consequently, it can not be considered as a plate boundary. The Boconó fault does however form the boundary between two different tectonic areas in the central part of the Mérida Andes as revealed by the earthquake focal mechanisms. South of the Boconó fault, the focal mechanisms are mainly compressional and reverse oblique-slip in agreement with NW SE shortening in the foothills. North of the Boconó fault, extensional and strike-slip deformation dominates. Microtectonic measurements collected in the central part of the Boconó fault are characterized by polyphased tectonics. The dextral shearing along the fault is superimposed to reverse oblique-slip to reverse motion, showing that initiation of transcurrent movement is more likely to have occurred after a certain amount of shortening. The present day strain partitioning along the Mérida Andes seems to be younger than the rise of the chain and coeval with the initiation of right-lateral shearing along the Boconó fault, which would have then initiated in the Pliocene. The Mérida Andes can be therefore considered as a case study of the kinematic evolution of a major strike-slip fault.

Backé, G.

2006-12-01

336

Breeding biology of the golden-faced Tyrannulet (Zimmerius chrysops) in venezuela  

USGS Publications Warehouse

We present the first detailed information on the breeding biology of the Golden-faced Tyrannulet (Zimmerius chrysops). Information was gathered from 96 nests in Yacamb National Park, Venezuela during the 2002 to 2008 breeding seasons. The enclosed nest was similar to descriptions of nests of other species in the genus. Eggs were laid on alternate days with mean (?? SE) clutch size of 1.98 ?? 0.02 (n 45) and fresh weight of 1.616 ?? 0.020 g (n 48). Only the female incubated and the incubation period averaged 16.9 ?? 0.3 days (n 10). Nest attentiveness ( time on the nest) averaged 66.0 ?? 1.6 (n 40) and increased from early to mid- and late-incubation. Incubation behavior yielded an average 24-hr egg temperature of 34.88 ?? 0.45?? C (n 7 nests, 43 days). The nestling growth rate constant for body mass (k 0.285 ?? 0.011) was slow even for tropical tyrannids. The nestling period for nests where exact hatch and fledging days were observed ranged from 17 to 19 days with an average of 18.0 ?? 0. 2 days (n 9). Both females and males fed nestlings at a rate that increased over the nestling period with a mean of 4.41 ?? 0.65 trips/hr (n 10) during days 1 and 2 after hatching, and 14.93 ?? 2.36 trips/hr (n 6) at pin-break (days 1011). Daily predation rates were similar in egg-laying (0.052 ?? 0.025; n 76.5 exposure days) and incubation periods (0.068 ?? 0.010; n 575.5 exposure days), but were lower during the nestling period (0.039 ?? 0.010; n 377.0 exposure days). The total daily predation rate (0.057 ?? 0.007; n 989.0 exposure days) indicated only 12 of nests were successful. These breeding biology parameters for Z. chrysops differ substantially from other tyrant-flycatchers and temperate species, further highlighting the diversity within the Tyrannidae. ?? 2010 by the Wilson Ornithological Society.

Goulding, W.; Martin, T.E.

2010-01-01

337

Heavy metals and organic carbon in sediments from the Tuy River basin, Venezuela.  

PubMed

The Tuy River basin, located in north-central Venezuela with an annual average temperature of 27°C and precipitation of 140 cm, was selected to conduct a geochemical study of bottom sediments, with the object of establishing the natural and human influences in the abundance and distribution of Fe, Mn, Cr, Co, Cu, Ni, Pb, Zn and organic carbon. The basin is lithologically divided into two sub-basins, north and south. The north sub-basin drains a iow-grade metasedimentary terrain with a population density of 800 persons km(-2) and approximateiy 600 industrial sites, while the south sub-basin in underlain by metavolcanic and ultramafic rocks, with a population density of less than 10 persons km(-2).Stream bottom sediment samples (150) were collected during the years of 1979-1986 in 16 unpolluted sites and 13 polluted sites. The sediments were air dried at room temperature and sieved through a 120 stainless steel mesh (125 ?m). Samples of grain size smaller than 125 ?m were analysed, the heavy metals being determined by atomic absorption spectrometry and the organic carbon (Corg) by dry combustion.The higher concentrations of heavy metals and organic carbon found in the pristine areas were in the south sub-basin, especially in those areas with higher annual precipitation and tropical forest. This indicated that the metavolcanic and ultramafic rocks yield higher concentrations of heavy metals than the metasedimentary rocks. It was also noted that the higher concentrations of Cr and Ni are associated with the ultramafic rocks. The results obtained from the sediment samples collected in the polluted sites showed that the elements Pb, Zn and Corg are enriched up to 4 times as a result of ail the human activities taking place in the basin. Organic carbon is an excellent indicator of domestic wastewater, Pb and Zn are good indicators of the automotive traffic and industrial effluents. The concentrations of each heavy metal did not show any significant correlation with grain size fractions; however, the concentration of organic carbon did show a negative correlation with grain size. The lithological, climatic and vegetation influence in the abundance of heavy metals and organic carbon in stream sediments clearly indicates the necessity of establishing background levels for the area under study when carrying out studies in environmental geochemistry. PMID:24202659

Mogollón, J L; Ramirez, A J; Guillén, R B; Bifano, C

1990-12-01

338

Least Limiting Water Range of soils in the Colonia Agrícola de Turen, Venezuela  

NASA Astrophysics Data System (ADS)

Soil physical degradation is a major problem affecting the soil quality for crops production in Venezuelan agricultural areas. The least limiting water range (LLWR) is considered a soil physical quality index defined as the range in soil water content within which the limitations to plant response associated with water potential, poor aeration and high mechanical resistance are minimal. The study was carried out to characterize the LLWR and to determine the LLWR response to structural changes on soils of the Colonia Agricola de Turen, Venezuela. The soils were cropped with maize under different tillage systems (no tillage, conventional and conventional - fallow) and non-cropped under native forest. Hundred and seventy undisturbed samples were taken from specific sites under each of the above soil conditions to determine the water retention curve, the soil resistance curve and bulk density. Disturbed samples were also taken from each site to determine particle size and organic matter content. Pedotransfer functions relating the water retention curve and soil resistance curve with particle size distribution, organic matter content and bulk density were developed and use to calculate the LLWR for each site. According to the results, soil physical degradation under conventional tillage and high clay content had the highest negative impact on the LLWR. For this case (silty clay loam soil), the LLWR became narrower due to the lower water content associated with poor aeration and the higher water content associated with high mechanical resistance. In contrast, for non degraded soils with high sand content (sandy loam) the LLWR showed the highest values associated with the water content at field capacity and the water content at permanent wilting point, both the upper and lower critical limits of LLWR. For silty loam and loam soils the LLWR declined with increasing bulk density and clay content associated with water content at field capacity and water content at high mechanical resistance. Soil resistance to root penetration determined the lower limit of LLWR in 41 % of the soils and the water content at field capacity determined the upper limit of LLWR in 94% of the soils. Further studies are recommended to determine the nature and magnitude of the association between the LLWR and crop yield under different soils and climate conditions.

Perez, Maiby Yolanda; Florentino de Andreu, Adriana

2013-04-01

339

First Description of KPC-2-Producing Klebsiella oxytoca Isolated from a Pediatric Patient with Nosocomial Pneumonia in Venezuela  

PubMed Central

During the last decade, carbapenem resistance has emerged among clinical isolates of the Enterobacteriaceae family. This has been increasingly attributed to the production of ?-lactamases capable of hydrolyzing carbapenems. Among these enzymes, Klebsiella pneumoniae carbapenemases (KPCs) are the most frequently and clinically significant class-A carbapenemases. In this report, we describe the first nosocomial KPC-2-producing K. oxytoca isolated from a pediatric patient with pneumonia admitted to the intensive care unit at The Andes University Hospital, Mérida, Venezuela. This strain was resistant to several antibiotics including imipenem, ertapenem, and meropenem but remained susceptible to ciprofloxacin, colistin, and tigecycline. Conjugation assays demonstrated the transferability of all resistance determinants, except aminoglycosides. The isolate LMM-SA26 carried a ~21?kb conjugative plasmid that harbored the blaKPC-2, blaCTX-M-8, and blaTEM-15 genes. Although carbapenem resistance in the Enterobacteriaceae is still unusual in Venezuela, KPCs have a great potential to spread due to their localization on mobile genetic elements. Therefore, rapid detection of KPC-carrying bacteria with phenotypic and confirmatory molecular tests is essential to establish therapeutic options and effective control measures. PMID:25405043

Labrador, Indira

2014-01-01

340

Development, Antibiotic Production, and Ribosome Assembly in Streptomyces venezuelae Are Impacted by RNase J and RNase III Deletion.  

PubMed

RNA metabolism is a critical but frequently overlooked control element affecting virtually every cellular process in bacteria. RNA processing and degradation is mediated by a suite of ribonucleases having distinct cleavage and substrate specificity. Here, we probe the role of two ribonucleases (RNase III and RNase J) in the emerging model system Streptomyces venezuelae. We show that each enzyme makes a unique contribution to the growth and development of S. venezuelae and further affects the secondary metabolism and antibiotic production of this bacterium. We demonstrate a connection between the action of these ribonucleases and translation, with both enzymes being required for the formation of functional ribosomes. RNase III mutants in particular fail to properly process 23S rRNA, form fewer 70S ribosomes, and show reduced translational processivity. The loss of either RNase III or RNase J additionally led to the appearance of a new ribosomal species (the 100S ribosome dimer) during exponential growth and dramatically sensitized these mutants to a range of antibiotics. PMID:25266378

Jones, Stephanie E; Leong, Vivian; Ortega, Joaquin; Elliot, Marie A

2014-12-15

341

Dengue seroprevalence and risk factors for past and recent viral transmission in Venezuela: a comprehensive community-based study.  

PubMed

Dengue transmission in Venezuela has become perennial and a major public health problem. The increase in frequency and magnitude of recent epidemics prompted a comprehensive community-based cross-sectional study of 2,014 individuals in high-incidence neighborhoods of Maracay, Venezuela. We found a high seroprevalence (77.4%), with 10% of people experiencing recent infections. Multivariate logistic regression analysis showed that poverty-related socioeconomic factors (place and duration of residence, crowding, household size, and living in a shack) and factors/constraints related to intradomiciliary potential mosquito breeding sites (storing water and used tires) were linked with a greater risk of acquiring a dengue infection. Our results also suggest that transmission occurs mainly at home. The combination of increasingly crowded living conditions, growing population density, precarious homes, and water storage issues caused by enduring problems in public services in Maracay are the most likely factors that determine the permanent dengue transmission and the failure of vector control programs. PMID:25223944

Velasco-Salas, Zoraida I; Sierra, Gloria M; Guzmán, Diamelis M; Zambrano, Julio; Vivas, Daniel; Comach, Guillermo; Wilschut, Jan C; Tami, Adriana

2014-11-01

342

Venezuela-MEM/USA-DOE Fossil Energy Report IV-11: Supporting technology for enhanced oil recovery - EOR thermal processes  

SciTech Connect

This report contains the results of efforts under the six tasks of the Tenth Amendment anti Extension of Annex IV, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Energy Agreement. This report is presented in sections (for each of the six Tasks) and each section contains one or more reports that were prepared to describe the results of the effort under each of the Tasks. A statement of each Task, taken from the Agreement Between Project Managers, is presented on the first page of each section. The Tasks are numbered 68 through 73. The first through tenth report on research performed under Annex IV Venezuela MEM/USA-DOE Fossil Energy Report Number IV-1, IV-2, IV-3, IV-4, IV-5, IV-6, IV-7, IV-8, IV-9, IV-10 contain the results of the first 67 Tasks. These reports are dated April 1983, August 1984, March 1986, July 1987, November 1988, December 1989, October 1991, February 1993, March 1995, and December 1997, respectively.

Venezuela

2000-04-06

343

PREFACE: XII Latin American workshop on plasma physics (17-21 September 2007, Caracas, Venezuela)  

NASA Astrophysics Data System (ADS)

Some years ago a group of Latin American physicists took the initiative to consult about the viability of organizing a meeting on plasma physics for researchers and students of the region. The result was that it was not only a good idea, but a necessity in order to show and share everyone's work, and to keep updated on latest advances and technologies on plasma physics. It was decided that for new researchers as well as students of Physics, it would prove to be the best way to keep them posted on such matters. This was the birth of a series of meetings known as Latin American workshops on plasma physics that take place every two years in a different Latin American country. In Venezuela we have had the opportunity to organize two editions of this interesting and important reunion of physicists. The first of these Latin American workshops on plasma physics was held in Cambuquira (Brazil) in 1982. After organizing the first six editions of the workshop, the VII LAWPP meeting was realized in Caracas in January 1997. It was designed with a structure similar to the first edition. It developed in two stages, a first week devoted to short courses with lecturers in different fields of plasma physics and a second week for contributed and invited presentations. Participants from sixteen different countries were present, half of them from this continent and the other half from overseas, demonstrating the international character of this meeting. There have been four more editions of the workshop and once again, we have had the opportunity to organize this latest edition of the series: the XII Latin American workshop on plasma physics, which took place in Caracas, Venezuela from the 17th to the 21st of September 2007. The structure was modified, because contributed and review papers were together during the first stage, with short courses realized during the second one, called mini-courses, and given by several high level contributors such as José Boedo, Leopoldo Soto, Claude Deutsch, Ricardo Galvao, Carlos Hidalgo, Paulo Sakanaka, Konosuke Sato, Malcom Haines and Maher Boulos. The general feeling is that these mini-courses were very successful. As an original idea of Professor Ricardo Magnus Osorio Galvão, Director of Centro Brasileiro de Pesquisas Físicas, we saluted the creation of The Vladimir Tsypin Award to the best Poster in the meeting. This prize was presented by Professor Galvão in memoriam of Vladimir Semenovich Tsypin. It was suggested that the granting of this award be made in every meeting from now on. We think that it is very important to emphasise the mini-courses due to the necessity of increasing in the near future a better formation for our young scientists. The contributions of all the lecturers are greatly appreciated. We had the typical fields in plasma physics as in past meetings. We also appreciated very much the lectures of Professor Malcolm Haines, Professor Sergey Popel, Professor Claude Deutsch, and Professor Antony Peratt for their very interesting talks on the Z-Pinch recorded to prehistory. Special thanks again to these lecturers since they have joined and honoured our meetings in the past as well. As in the VII LAWPP, all the sessions of the workshop were held at the Universidad Simon Bolivar campus, located in the nice green Valley of Sartenejas near Caracas. We also appreciate the stimulus and the financial support that we have always had for the preparation of these workshops from our institution by means of its authorities: Professor Benjamin Sharifker (Rector), Professor Aura Lopez (Dean of Academic Activities), (Professor Jose Luis Paz (Dean of Research and Development), Professor Pedro Berrisbeitia (Dean of Postgraduate Studies) and Professor William Colmenares (Dean of Extended Activities). We must also mention and appreciate the collaboration of architect Alejandro Chataing Roncajolo as Secretary and Coordinator of the Congress, as well as the daily important collaborations of our students Anais Möller, Laura Beiras, Juan Contreras, Gabriel Torrente, Aimée Guerrero, Francisco Jose Blanco

Puerta, Julio

2008-10-01

344

Dirio Econmico -Universidades Como ser investigador em Portugal  

E-print Network

Diário Económico - Universidades Como é ser investigador em Portugal Autor: N.D. Editora: ST e SF - Universidades Como é ser investigador em Portugal Autor: N.D. Editora: ST e SF Id: 1646658 Data Publicação: 19

Instituto de Sistemas e Robotica

345

Hypsilara royi gen. n. and sp. n. (Coleoptera, Elmidae, Larainae) from Southern Venezuela, with a revised key to Larainae of the Western Hemisphere  

E-print Network

Here we describe a new genus, for a new species of riffle beetle, Hypsilara royi gen. n. and sp. n., from the tepui Cerro de la Neblina in southern Venezuela. This new genus can be distinguished from all other laraine genera by its small size (ca. 4...

Maier, Crystal A.; Spangler, Paul J.

2011-07-07

346

Diurnal changes in photochemical efficiency, the reduction state of Q, radiationless energy dissipation, and non-photochemical fluorescence quenching in cacti exposed to natural sunlight in northern Venezuela  

Microsoft Academic Search

Diurnal measurements of chlorophyll a fluorescence from cacti (Nopalea cochenillifera, Opuntia ficus-indica, and Opuntia wentiana) growing in northern Venezuela were used to determine photochemical fluorescence quenching related to the reduction state of the primary electron acceptor of PS II as well as non-photochemical fluorescence quenching which reflects the fraction of energy going primarily into radiationless deexcitation. The cladodes used in

W. W. Adams; M. Díaz; K. Winter

1989-01-01

347

A test for the adequacy of bioindicator taxa: Are tiger beetles (Coleoptera: Cicindelidae) appropriate indicators for monitoring the degradation of tropical forests in Venezuela?  

Microsoft Academic Search

Indicator species can be a valuable tool for conservation research. Their use has been divided in two categories: inventory studies and monitoring studies. Tiger beetles (Coleoptera: Cicindelidae) have been identified as appropriate indicators for inventory studies. Here we test their value as potential bioindicators for monitoring habitat degradation in Venezuela. We analyze the general habitat associations of 47 of the

Jon Paul Rodríguez; David L. Pearson; Roberto R. Barrera

1998-01-01

348

Fluvial geochemistry of the eastern slope of the northeastern Andes and its foredeep in the drainage of the Orinoco in Colombia and Venezuela  

Microsoft Academic Search

The fluvial geochemistry of the tributaries of the Orinoco draining the eastern branch of the northern Andes in Colombia and Venezuela is determined by lithology and ranges from rivers dominated by aluminosilicate weathering, mainly of shales and mafic rocks, to those bearing the signatures of dissolution of marine limestones and evaporites and of continental playa deposits. These left bank tributaries

J. M. Edmond; M. R. Palmer; C. I. Measures; E. T. Brown; Y. Huh

1996-01-01

349

Comparison of Petrophysical Rock Types from Core and Well-logs using Post-stack 3D Seismic Data: Field Example from Maracaibo-Venezuela  

E-print Network

Comparison of Petrophysical Rock Types from Core and Well-logs using Post-stack 3D Seismic Data with post stack 3D seismic data analysis was used to assess the petrophysical rock type distribution in an area located on the West side of Lake Maracaibo-Venezuela. The calculated petrophysical rock types were

Ramachandran, Kumar

350

Monitoring a Recent Delta Formation in a Tropical Coastal Wetland Using Remote Sensing and GIS. Case Study: Guapo River Delta, Laguna de Tacarigua, Venezuela  

Microsoft Academic Search

The integrated use of remotely sensed data and GIS to monitor a rapid recent delta formation was undertaken in the Tacarigua Lagoon, a mangrove coastal protected wetland in the north-central coast of Venezuela. Recently, the resource value of coastal wetlands such as coastal lagoons and deltas, has brought about a need to protect and conserve these ecosystems. To that end,

A. Calzadilla Pérez; M. C. J. Damen; D. Geneletti; T. W. Hobma

2002-01-01

351

A reservoir engineering characterization of the north study area of the C2/VLE-305 reservoir, Lamar Field, Lake Maracaibo, Venezuela  

E-print Network

on the C2/VLE-305 reservoir unit in Lake Maracaibo, Venezuela and is used to illustrate the application of our modified FZI parameter. Our target reservoir member is the C2 unit which has been divided into five "flow units" (C20, C21 S, C211, C22 and C23...

Padron Cabral, Ricardo Javier

1994-01-01

352

Preconceptos sobre el odontólogo y la consulta odontológica por parte de niños de séptimo grado en una institución rural en el estado Trujillo, Venezuela  

Microsoft Academic Search

RESUMEN El rol del odontólogo en la prevención, educación y cuidados para la rehabilitación del sistema estoma- tognático es de notable importancia para la salud del individuo. Sin embargo, no existe una adecuada difu- sión sobre el rol del odontólogo. Por lo tanto, es de esperar que existan preconceptos erróneos en los niños acerca de este profesional y sus funciones,

TRABAJO DE INVESTIGACIÓN

353

The detection and PCR-based characterization of the parasites causing trypanosomiasis in water-buffalo herds in Venezuela.  

PubMed

The usefulness of PCR-based assays for detecting trypanosomiasis in water buffaloes and other livestock was explored, under field conditions, in Venezuela. The sensitivity and specificity of the assays, which were based on established primer pairs (21-mer/22-mer and ILO1264/ILO1265), were evaluated, partly by comparison with the results of parasitological tests (stained bloodsmears and microhaematocrit centrifugation) and immunological assays (IFAT) run in parallel. The optimised PCR-based assays showed a sensitivity of 10 pg DNA. The use of the 21-mer/22-mer primer pair gave a test that was specific for species in the subgenus Trypanozoon (including Trypanosoma evansi), whereas use of ILO1264/ILO1265 produced a test that was specific for T. vivax. The results of a hybridization assay using T. evansi-DNA and T. vivax-DNA probes indicated no cross-hybridization between the T. evansi and T. vivax PCR products.The results of the bloodsmear examinations, microhaematocrit centrifugations (MHC) and IFAT indicated that 23 (6.7%), 39 (11.4%) and 135 (39.5%) of the 342 blood samples investigated (including 316 from water buffaloes) contained trypanosomes, respectively. The results of the PCR-based assays indicated that 68 (19.9%) of the same blood samples contained T. vivax (or at least T. vivax DNA), and that none contained T. evansi or any other member of the subgenus Trypanozoon. For the detection of trypanosomes, the assay therefore appeared almost twice as sensitive as the MHC. These results are the first on the molecular characterization of the trypanosomes infecting water buffaloes in Venezuela. When the results of the MHC (which is the most practical, and frequently used, alternative detection method) were used as the gold standard, the PCR-based assay for T. vivax was found to have 100% sensitivity, 90.4% specificity, a positive predictive value of 0.57, a positive likelihood ratio of 10.45, and a negative likelihood ratio of 0.00. The assay therefore appears a reasonable choice for detecting T. vivax in the mammalian livestock of Venezuela and elsewhere. PMID:15949183

Garcia, H; Garcia, M-E; Perez, H; Mendoza-Leon, A

2005-06-01

354

Debris-flow and flooding hazards associated with the December 1999 storm in coastal Venezuela and strategies for mitigation  

USGS Publications Warehouse

Heavy rainfall from the storm of December 14-16, 1999 triggered thousands of landslides on steep slopes of the Sierra de Avila north of Caracas, Venezuela. In addition to landslides, heavy rainfall caused flooding and massive debris flows that damaged coastal communities in the State of Vargas along the Caribbean Sea. Examination of the rainfall pattern obtained from the GOES-8 satellite showed that the pattern of damage was generally consistent with the area of heaviest rainfall. Field observations of the severely affected drainage basins and historical records indicate that previous flooding and massive debris-flow events of similar magnitude to that of December 1999 have occurred throughout this region. The volume of debris-flow deposits and the large boulders that the flows transported qualifies the 1999 event amongst the largest historical rainfall-induced debris flows documented worldwide.

Wieczorek, G.F.; Larsen, M.C.; Eaton, L.S.; Morgan, B.A.; Blair, J.L.

2001-01-01

355

Gyrodactylus poeciliae n. sp. and G. milleri n. sp. (Monogenea: Gyrodactylidae) from Poecilia caucana (Steindachner) in Venezuela.  

PubMed

Two new species of Gyrodactylus are described from the South American live-bearing fish Poecilia caucana from Venezuela. Gyrodactylus poeciliae n. sp. is characterised by conspicuous ventral bar processes and by marginal hooks in which the tips are barely curved. Morphologically, the species resembles G. bullatarudis and G. costaricensis, and its relationship to the former was confirmed by sequencing the Internal Transcribed Spacers (ITS-1 and ITS-2) and the 5.8S ribosomal gene of the ribosomal DNA. Gyrodactylus milleri n. sp. was characterised by large, sharply angled marginal hook sickles in which the tips overhang the toes. This species resembled most closely G. turnbulli from guppies. These descriptions confirm the occurrence of G. turnbulli and G. bullatarudis-like gyrodactylids on a range of South American poeciliid fishes. PMID:10966215

Harris, P D; Cable, J

2000-10-01

356

The use of radar and LANDSAT data for mineral and petroleum exploration in the Los Andes region, Venezuela  

NASA Technical Reports Server (NTRS)

A geological study of a 27,500 sq km area in the Los Andes region of northwestern Venezuela was performed which employed both X-band radar mosaics and computer processed Landsat images. The 3.12 cm wavelength radar data were collected with horizontal-horizontal polarization and 10 meter spatial resolution by an Aeroservices SAR system at an altitude of 12,000 meters. The radar images increased the number of observable suspected fractures by 27 percent over what could be mapped by LANDSAT alone, owing mostly to the cloud cover penetration capabilities of radar. The approximate eight fold greater spatial resolution of the radar images made possible the identification of shorter, narrower fractures than could be detected with LANDSAT data alone, resulting in the discovery of a low relief anticline that could not be observed in LANDSAT data. Exploration targets for petroleum, copper, and uranium were identified for further geophysical work.

Vincent, R. K.

1980-01-01

357

Temporal variations of heavy metals levels in Perna viridis, on the Chacopata-Bocaripo lagoon axis, Sucre State, Venezuela.  

PubMed

Perna viridis was used as biomonitor to assess heavy metal levels in the Chacopata-Bocaripo lagoon axis, Venezuela, during rain and drought seasons. The mussels were weighed and measured. The metal concentrations were determined by atomic absorption spectrophotometry. For rain period, the order of bioavailability was: Cu>Ni>Mn>Co>Cd>Pb, and for drought: Cu>Mn>Ni>Co>Pb>Cd. The concentrations of Ni, Co, Cd and Pb showed significant differences (P<0.05) in both periods. There was higher metal accumulation during drought season, possibly related to upwelling, since it produces an increase in primary productivity, which translates more food into organisms, making metals bioavailable for mussels. Only Cu and Mn showed significant relationships between the size and metal concentration, during drought period, it may be because of the organisms need for these essential metals in different physiological processes. PMID:25444616

Pinto, Rafael; Acosta, Vanessa; Segnini, Mary Isabel; Brito, Leonor; Martínez, Gregorio

2014-10-30

358

Large-scale shrimp farming in coastal wetlands of Venezuela, South America: Causes and consequences of land-use conflicts  

NASA Astrophysics Data System (ADS)

In Venezuela, large-scale shrimp farming began in the 1980s. By 1987, the Ministry of Environment and Natural Resources (MARNR) had received 14 proposals for approval. A developer illegally started the construction of ponds at the Píritu Lagoon in the State of Anzoátegui before the authorization process was completed. This action triggered a land-use conflict. This study identifies the causes for public protest and determines the consequences of this conflict for land-use management. The results show that public protest was based on the impacts of the partial construction of ponds. These impacts were related to direct removal of wetlands, interruption of natural patterns of surface flows, and alteration of feeding grounds of some bird species with migratory status. Consequences were identified in relation to the role that nongovernmental organizations (NGOs) play in land-use conflicts and the actions that MARNR could take in the future to prevent and solve similar situations.

Sebastiani, Mirady; González, Sara Elena; Castillo, María Mercedes; Alvizu, Pablo; Oliveira, María Albertina; Pérez, Jorge; Quilici, Antonio; Rada, Martín; Yáber, María Carolina; Lentino, Miguel

1994-09-01

359

Semi-Periodic Sequences and Extraneous Events in Earthquake Forecasting. II: Application, Forecasts for Japan and Venezuela  

NASA Astrophysics Data System (ADS)

In order to analyze observed seismicity in central Japan and Venezuela, we applied a new method to identify semi-periodic sequences in the occurrence times of large earthquakes, which allows for the presence of multiple periodic sequences and/or events not belonging to any sequence in the time series. We also explored a scheme for diminishing the effects of a sharp cutoff magnitude threshold in selecting the events to analyze. A main four-event sequence with probability P c = 0.991 of not having occurred by chance was identified for earthquakes with M ? 8.0 in central Japan. Venezuela is divided, from West to East, into four regions; for each of these, the magnitude ranges and identified sequences are as follows. Region 1: M ? 6.0, a six-event sequence with P c = 0.923, and a four-event sequence with P c = 0.706. Region 2: M ? 5.6, a five-event sequence with P c = 0.942. Region 3: M ? 5.6, a four-event sequence with P c = 0.882. Region 4: M ? 6.0, a five-event sequence with P c = 0.891. Forecasts are made and evaluated for all identified sequences having four or more events and probabilities ?0.5. The last event of all these sequences was satisfactorily aftcast by previous events. Whether the identified sequences do, in fact, correspond to physical processes resulting in semi-periodic seismicity is, of course, an open question; but the forecasts, properly used, may be useful as a factor in seismic hazard estimation.

Quinteros Cartaya, Claudia Beatriz; Nava Pichardo, Fidencio Alejandro; Glowacka, Ewa; Frez Cárdenas, José Duglas

2014-07-01

360

Recurrent wheezing is associated with intestinal protozoan infections in Warao Amerindian children in Venezuela: a cross-sectional survey  

PubMed Central

Background While in developed countries the prevalence of allergic diseases is rising, inflammatory diseases are relatively uncommon in rural developing areas. High prevalence rates of helminth and protozoan infections are commonly found in children living in rural settings and several studies suggest an inverse association between helminth infections and allergies. No studies investigating the relationship between parasitic infections and atopic diseases in rural children of developing countries under the age of 2 years have been published so far. We performed a cross-sectional survey to investigate the association of helminth and protozoan infections and malnutrition with recurrent wheezing and atopic eczema in Warao Amerindian children in Venezuela. Methods From August to November 2012, 229 children aged 0 to 2 years residing in the Orinoco Delta in Venezuela were enrolled. Data were collected through standardized questionnaires and physical examination, including inspection of the skin and anthropometric measurements. A stool sample was requested from all participants and detection of different parasites was performed using microscopy and real time polymerase chain reaction (PCR). Results We observed high prevalence rates of atopic eczema and recurrent wheezing, respectively 19% and 23%. The prevalence of helminth infections was 26% and the prevalence of protozoan infections was 59%. Atopic eczema and recurrent wheezing were more frequently observed in stunted compared with non-stunted children in multivariable analysis (OR 4.3, 95% CI 1.3 – 13.6, p?=?0.015 and OR 4.5, 95% CI 0.97 – 21.2, p?=?0.055). Furthermore, recurrent wheezing was significantly more often observed in children with protozoan infections than in children without protozoan infections (OR 6.7, 95% CI 1.5 – 30.5). Conclusions High prevalence rates of atopic eczema and recurrent wheezing in Warao Amerindian children under 2 years of age were related to stunting and intestinal protozoan infections respectively. Helminth infections were not significantly associated with either atopic eczema or recurrent wheezing. PMID:24885094

2014-01-01

361

Montelukast for the high impact of asthma exacerbations in Venezuela: a practical and valid approach for Latin America?  

PubMed Central

Background Asthma affects mainly Venezuela’s urban and poor majority. Exacerbations bring about a high demand in health services, thus becoming a significant public health problem. In general, asthma control programs (GINA) with use of inhaled steroid medications have proven effective, although their implementation in real life remains cumbersome. Montelukast could be a useful and practical tool for these deprived socioeconomic sectors. Methods This real-life pilot study was conducted in a prospective, double blinded, placebo-controlled manner with randomized and parallel groups. Asthmatics that had never used leukotriene modifiers were recruited and followed-up every three months. The main outcome was the number of exacerbations meriting use of nebulized bronchodilators administered by the health care system. Results Eighty-eight asthmatic patients were enrolled, between children and adults. Groups were comparable in: demographic data, previous use of other medications, ACT scores, pulmonary functions (Wright Peak Flow meter), allergy status (Skin Prick Test) as well as adherence to the prescribed Montelukast treatment. By an intention to treat (ITT), a total of 64 patients were included for analysis. For the three and six months time points the difference between placebo and Montelukast was found to be significant (p < 0.03 and p < 0.04, respectively). Such trends continued for the rest of the year, but without statistical significance, due to patient attrition. Conclusions This real-life pilot study shows that a simplified strategy with oral Montelukast was practical and effective in controlling exacerbations in an asthmatic population of a vulnerable community from Caracas. Such an approach reinforces the role of primary care in asthma treatment. PMID:25232371

2014-01-01

362

NORMAS GERAIS PARA INGRESSO COMO PORTADOR DE DIPLOMA DE  

E-print Network

1 NORMAS GERAIS PARA INGRESSO COMO PORTADOR DE DIPLOMA DE GRADUA��O (BRASIL) PERÍODO 2013.1 PRAZO COMO PORTADOR DE DIPLOMA DE GRADUA��O DO BRASIL I­DAS CONDI��ES Portadores de Diploma de Graduação de; - Certificado de Dispensa de Incorporação; - CPF; Se candidato estrangeiro: - Certificado de

363

Trypanosoma cruzi genotyping supports a common source of infection in a school-related oral outbreak of acute Chagas disease in Venezuela.  

PubMed

Trypanosoma cruzi I, a discrete typing unit (DTU) found in human infections in Venezuela and other countries of the northern region of South America and in Central America, has been recently classified into five intra-DTU genotypes (Ia, Ib, Ic, Id, Ie) based on sequence polymorphisms found in the spliced leader intergenic region. In this paper we report the genotype identification of T. cruzi human isolates from one outbreak of acute orally acquired Chagas disease that occurred in a non-endemic region of Venezuela and from T. cruzi triatomine and rat isolates captured at a guava juice preparation site which was identified as the presumptive source of infection. The genotyping of all these isolates as TcId supports the view of a common source of infection in this oral Chagas disease outbreak through the ingestion of guava juice. Implications for clinical manifestations and dynamics of transmission cycles are discussed. PMID:23544849

Díaz-Bello, Z; Thomas, M C; López, M C; Zavala-Jaspe, R; Noya, O; DE Noya, B Alarcón; Abate, T

2014-01-01

364

Trypanosoma cruzi III from armadillos (Dasypus novemcinctus novemcinctus) from Northeastern Venezuela and its biological behavior in murine model. Risk of emergency of Chagas' disease.  

PubMed

Trypanosoma cruzi, etiological agent of Chagas' disease, was isolated from armadillos (Dasypus novemcinctus novemcinctus) captured in rural communities Northeastern Venezuela from Nueva Esparta State (no endemic for Chagas' disease), Monagas and Anzoátegui States (endemics). The isolates, genetically typed by PCR-RFLP as belonging to the TcIII DTU, have demonstrated in murine model heterogenic parasitemia, mortality and histotropism with marked parasitism in cardiac, skeletal, and smooth myocytes that showed correlation with lymphobasophilic inflammatory infiltrates. Our finding of T. cruzi infected armadillos in Isla Margarita (Nueva Esparta State), together with reports of triatomine vectors in this region, the accentuated synanthropy of armadillos, intense economic activity, migration due to tourism and the lack of environmental education programs all of them represent risks that could cause the emergence of Chagas' disease in this area. This is the first report of the TcIII DTU in Northeastern Venezuela, thus widening the geographic distribution of this DTU. PMID:22902748

Morocoima, Antonio; Carrasco, Hernán J; Boadas, Johanna; Chique, José David; Herrera, Leidi; Urdaneta-Morales, Servio

2012-11-01

365

Anomalously high activities of 137 Cs in soils and vegetation on and near a diabase outcrop in La Sierra de Lema, Venezuela  

Microsoft Academic Search

As a result of routine soil sampling to determine the 137Cs background activities country-wide in Venezuela, it was decided to further investigate El Mirador (Lookout) area at the\\u000a base of the Sierra de Lema mountain range. In April 2003 (A), soil samples were collected at eight sites on and around the\\u000a edge of the diabase outcrop to confirm that this

J. J. LaBrecque; J. A. Alfonso; P. R. Cordoves

2008-01-01

366

Characterization of the Mineral Phosphate-Solubilizing Activity of Pantoea aglomerans MMB051 Isolated from an Iron-Rich Soil in Southeastern Venezuela (Bolívar State)  

Microsoft Academic Search

The mineral phosphate-solubilizing (MPS) activity of a Pantoea agglomerans strain, namely MMB051, isolated from an iron-rich, acidic soil near Ciudad Piar (Bolívar State, Venezuela), was characterized\\u000a on a chemically defined medium (NBRIP). Various insoluble inorganic phosphates, including tri-calcium phosphate [Ca3(PO4)2], iron phosphate (FePO4), aluminum phosphate (AlPO4), and Rock Phosphate (RP) were tested as sole sources of P for bacterial growth.

Miguel Sulbarán; Elizabeth Pérez; María M. Ball; Alí Bahsas; Luis Andrés Yarzábal

2009-01-01

367

Organic geochemical investigation and coal-bed methane characteristics of the Guasare coals (Paso Diablo mine, western Venezuela)  

USGS Publications Warehouse

The aim of this work was to carry out a geochemical study of channel samples collected from six coal beds in the Marcelina Formation (Zulia State, western Venezuela) and to determine experimentally the gas content of the coals from the Paso Diablo mine. Organic geochemical analyses by gas chromatography-mass spectrometry and isotopic analyses on-line in coalbed gas samples were performed. The results suggest that the Guasare coals were deposited in a continental environment under highly dysoxic and low salinity conditions. The non-detection of 18??(H)-oleanane does not preclude that the organic facies that gave rise to the coals were dominated by angiosperms. In addition, the presence of the sesquiterpenoid cadalene may indicate the subordinate contribution of gymnosperms (conifers) in the Paleocene Guasare mire. The average coalbed gas content obtained was 0.6 cm3/g. ??13C and D values indicate that thermogenic gas is prevalent in the studied coals. Copyright ?? Taylor & Francis Group, LLC.

Quintero, K.; Martinez, M.; Hackley, P.; Marquez, G.; Garban, G.; Esteves, I.; Escobar, M.

2011-01-01

368

First description of the breeding biology and natural history of the ochre-breasted brush finch atlapetes semirufus in venezuela  

USGS Publications Warehouse

We provide the first description of the eggs, breeding biology, and natural history of the Ochre-breasted Brush Finch (Atlapetes semirufus). We found 37 nests over four breeding seasons (2004-2007) in Yacamb?? National Park, Venezuela. Nesting activity started in late April and continued until early June suggesting single-brooded behavior despite a typical tropical clutch size of two eggs (x?? = 1.89) that were laid on consecutive days. Egg mass averaged 3.38 g and 11.6% of adult female mass. The incubation and nestling periods averaged 14.9 and 10.5 days, respectively. Only females incubated and the percent time they spent incubating did not change between early and late incubation. Females brooded 42.7% of the time when nestlings were 2 days of age and 20.5% when 9 days of age. Both parents provisioned young at a low rate (3.9 trips/hr) and nestling growth rate (k = 0.45) was also slow. Nest predation rates were relatively high with daily mortality rates of 0.058 and 0.067 during incubation and nestling stages, respectively.

Biancucci, L.; Martin, T.E.

2008-01-01

369

Breeding biology of the Three-striped warbler in Venezuela: A contrast between tropical and temperate parulids  

USGS Publications Warehouse

We document reproductive life history traits of the Three-striped Warbler (Basileuterus tristriatus) from 146 nests in Venezuela and compare our results to data from the literature for other tropical and temperate parulid species. Mean (?? SE) clutch size was 1.96 ?? 0.03 eggs (n = 96) and fresh egg mass was 2.09 ?? 0.02 g. The incubation period was 15.8 ?? 0.2 days (n = 23) and the nestling period was 10.5 ?? 0.3 days (n = 12). Males did not incubate and rarely provided food for females during incubation. Females had 57 ?? 2% (n = 49) nest attentiveness (% of time on the nest incubating), which caused egg temperature to commonly become cold relative to development. Both adults fed nestlings and feeding rates increased with nestling age. The growth rate constant for nestlings based on mass was K 0.490, which is slower than for north temperate warblers. Predation was the primary source of nest failure and only 22% of nests were successful based on a Mayfield daily predation rate of 0.048 ?? 0.006. Our literature review indicates parulids differ strongly in life histories between temperate and tropical/subtropical sites with species in the tropics having, on average, smaller clutches, longer incubation periods, lower nest attentiveness, longer off-bouts, and longer nestling periods. ?? 2009 by the Wilson Ornithological Society.

Cox, W.A.; Martin, T.E.

2009-01-01

370

A new Dasypodini armadillo (Xenarthra: Cingulata) from San Gregorio Formation, Pliocene of Venezuela: affinities and biogeographic interpretations  

NASA Astrophysics Data System (ADS)

We describe Pliodasypus vergelianus gen. et sp. nov., a Dasypodini armadillo from the middle Pliocene of Venezuela (Vergel Member, San Gregorio Formation). Although scarce, the remains are remarkable because of their geochronologic proximity to the main phase of Great American Biotic Interchange (GABI). The cladistic analysis conducted reveals that Pliodasypus groups with Dasypus and both are sister taxa of Propraopus, whereas Anadasypus is at a basal position. With respect to the records of tribe Dasypodini, after its oldest representative ( Anadasypus, middle and late Miocene), the chronologically subsequent form is Pl. vergelianus (middle Pliocene), followed by Dasypus bellus in higher northern latitudes (late Pliocene), and then by widespread occurrences in the Pleistocene of North America ( D. bellus) and South America ( Propraopus, Dasypus punctatus, and Dasypus novemcinctus). Thus, we infer that Dasypus differentiated in the late Pliocene at low latitudes in the northern South America. It leads to two alternative hypotheses of dispersal: (a) some early Dasypus remained cryptically in South America until the Pleistocene, whereas others dispersed to North America between 2.2 and 2.7 Ma, or (b) they dispersed to North America subsequently to the emersion of the Panamanian isthmus and D. bellus differentiated there; later, during the Pleistocene, D. bellus entered South America and experienced speciation. The same process of re-ingression has been proposed to other xenarthrans, breaking with the traditional assumption that the GABI was unidirectional.

Castro, Mariela C.; Carlini, Alfredo A.; Sánchez, Rodolfo; Sánchez-Villagra, Marcelo R.

2014-02-01

371

Debris-flow and flooding deposits in coastal Venezuela associated with the storm of December 14-16, 1999  

USGS Publications Warehouse

Heavy rainfall from the storm of December 14?16, 1999, triggered thousands of shallow landslides on steep slopes of the Sierra de Avila north of Caracas, Venezuela, and caused flooding and massive debris flows in the channels of major drainages that severely damaged coastal communities along the Caribbean Sea. Within this region we characterized geologic conditions where landslides initiated on hillsides and examined the texture of debris-flow deposits in the channels of nine drainages. In one of the most severely damaged areas on a highly developed alluvial fan at Caraballeda, we measured debris-flow deposits that ranged up to 5 meters (m) in thickness, inundating structures and roads over a large portion of the fan. Boulders up to 5 m long were carried along by the flows, impacted structures causing serious damage, and were deposited on the fan. Using field measurements and comparing pre-event and post-event topography from aerial photographs, we determined the volume of debris-flow and flood deposition on the fan to be about 2 million cubic meters. The total volume of material transported and deposited by landslides throughout the Vargas region ranks this as one of the most severe historical erosional events worldwide.

Wieczorek, Gerald F.; Larsen, Matthew C.; Eaton, L. Scott; Morgan, Benjamin A.; Blair, J. Luke

2002-01-01

372

Evaluation of the Seismic Hazard in Venezuela with a revised seismic catalog that seeks for harmonization along the country borders  

NASA Astrophysics Data System (ADS)

Probabilistic Seismic Hazard Assessment is a complex endeavor that relies on the quality of the information that comes from different sources: the seismic catalog, active faults parameters, strain rates, etc. Having this in mind, during the last several months, the FUNVISIS seismic hazard group has been working on a review and update of the local data base that form the basis for a reliable PSHA calculation. In particular, the seismic catalog, which provides the necessary information that allows the evaluation of the critical b-value, which controls how seismic occurrence distributes with magnitude, has received particular attention. The seismic catalog is the result of the effort of several generations of researchers along the years; therefore, the catalog necessarily suffers from the lack of consistency, homogeneity and completeness for all ranges of magnitude over any seismic study area. Merging the FUNVISIS instrumental catalog with the ones obtained from international agencies, we present the work that we have been doing to produce a consistent seismic catalog that covers Venezuela entirely, with seismic events starting from 1910 until 2012, and report the magnitude of completeness for the different periods. Also, we present preliminary results on the Seismic Hazard evaluation that takes into account such instrumental catalog, the historical catalog, updated known fault geometries and its correspondent parameters, and the new seismic sources that have been defined accordingly. Within the spirit of the Global Earthquake Model (GEM), all these efforts look for possible bridges with neighboring countries to establish consistent hazard maps across the borders.

Rendon, H.; Alvarado, L.; Paolini, M.; Olbrich, F.; González, J.; Ascanio, W.

2013-05-01

373

Reproductive biology of the violet-chested hummingbird in Venezuela and comparisons with other tropical and temperate hummingbirds  

USGS Publications Warehouse

We provide details on the breeding biology of the Violet-chested Hummingbird (Sternoclyta cyanopectus) based on 67 nests studied in Yacambu?? National Park, Venezuela, from 2002 through 2006. Clutch size was two white eggs, usually laid every other day. Fresh egg mass (0.95 ?? 0.14 g) was 15% of female mass. Incubation and nestling periods were 20.4 ?? 0.3 and 26.0 ?? 0.4 days, respectively. Nest attentiveness increased from 60% in early incubation to 68% in late incubation. The female spent 50% of her time brooding young nestlings, but ceased brooding by 13 days of age. Only the female fed the young, with a low rate of nest visitation (3.3 trips per hour) that did not increase with age of the young. Growth rate based on nestling mass (K = 0.28) was slow. Daily predation rates decreased across stages and were 0.064 ?? 0.044, 0.033 ?? 0.008, and 0.020 ?? 0.006 during the egg-laying, incubation, and nestling periods, respectively. Most, but not all, life history traits of the Violet-chested Hummingbird were similar to those reported for other tropical and temperate hummingbirds, providing further evidence that this family shows a relatively narrow range of life history variation. ?? The Cooper Ornithological Society 2007.

Fierro-Calderon, K.; Martin, T.E.

2007-01-01

374

[Nitrogen, phosphorus and the C/N ratio in superficial sediments of the lagoon of Chacopata, Sucre, Venezuela].  

PubMed

The basal behaviour and relationship with organic carbon (Corg) content and prevailing granulometric fractions, of organic nitrogen (Norg), total phosphorus (P-total) and C/N ratio in surface sediments of Chacopata lagoon, Sucre State, Venezuela, were studied. Concentrations and spatial gradients were determined in sixteen stations following a common method for marine sediments. Norg concentrations varied between 0.102 and 0.510% (x = 0.237%), total phosphorus between 0.012 and 0.094% (x = 0.058%) and C/N ratio between 9.27 and 44.47 (x = 20.53). The higher contents of Norg and total phosphorus are from sections with an abundance of mangroves, marine phanerogams, macroalgae, benthonic biomass and migratory birds shelters. The C/N ratio shows the typical values for carbonated sediments, indicating that the nitrogenous compounds are rapidly degraded and the organic matter presents itself as humic substances. This parameter was moderately associated with silt and clay, and showed antagonism with sand, whereas Norg and phosphorus showed no correlation with them. The organic contribution is purely autochthonous: no anthropogenous contributions were found. PMID:15266816

Fuentes Hernández, M V

2000-12-01

375

[Association of sardine fishery, Sardinella aurita (Teleostei: Clupeidae) and environmental variability of the coastal upwelling ecosystem of Nueva Esparta, Venezuela].  

PubMed

The present research is an analysis of Spanish sardine fishing (Sardinella aurita) associated with some climatic and meteorologic parameters of the ecosystem from El Morro Nueva Esparta, Venezuela. The catch and environmental data from the area were taken in the period 1996-2000. Catch data as a function of wind speed, sea surface temperature, air temperature and rain were analyzed by means of simple lineal regression and multiple models. We found a positive correlation of catch with wind speed, and a negative correlation with sea surface temperature, air temperature, and rain. The multiple regression model with intercept had a poor fit, therefore, we made a model without intercept, which improve greatly the fit. A selection of the variables using the forward procedure verified that the independent variables "wind speed" and "air temperature" have a significant relation with catch (p < 0.001) at real time. This method suggests that sea surface temperature and rain have little influence on the catch, and suggests a major availability of resources in the months with low air temperature and the highest wind speed (January-June). Rev. PMID:18457137

Gonz?lez, Leo W; Euán, Jorge; Eslava, Nora; Suniaga, Jesús

2007-03-01

376

Arbuscular mycorrhizal fungi communities in a coral cay system (Morrocoy, Venezuela) and their relationships with environmental variables.  

PubMed

Knowledge of the natural diversity of arbuscular mycorrhizal fungi (AMF) and understanding of their biogeographical patterns and what drive them might help to the maintenance and preservation of ecosystems under a changing environment. The objective of this study was to evaluate the contribution of different environmental factors to the determination of the composition of AMF assemblages in representative sites within the Morrocoy National Park (Venezuela). The community structure of the AMF under the canopy of Coccoloba uvifera was investigated in four cays (Borracho, Muerto, Peraza, and Paiclás) and one mainland location (Las Luisas). Based on partial sequences of the nuclear small subunit ribosomal DNA gene, the AM fungi in soil samples were divided into 31 operational taxonomic units, grouped in eight families. The canonical correspondence analysis showed that environmental factors related to insularity (the mean annual rainfall, the distance to the mainland coast, and the cay land area) and a soil property related to biological activity (the total carbohydrate content) were significantly related to the distribution of the AMF communities. PMID:25461083

Alguacil, M M; Torrecillas, E; Lozano, Z; Roldán, A

2015-02-01

377

Approaches to identifying reservoir heterogeneity and reserve growth opportunities from subsurface data: The Oficina Formation, Budare field, Venezuela  

SciTech Connect

We applied an integrated geologic, geophysical, and engineering approach devised to identify heterogeneities in the subsurface that might lead to reserve growth opportunities in our analysis of the Oficina Formation at Budare field, Venezuela. The approach involves 4 key steps: (1) Determine geologic reservoir architecture; (2) Investigate trends in reservoir fluid flow; (3) Integrate fluid flow trends with reservoir architecture; and (4) Estimate original oil-in-place, residual oil saturation, and remaining mobile oil, to identify opportunities for reserve growth. There are three main oil-producing reservoirs in the Oficina Formation that were deposited in a bed-load fluvial system, an incised valley-fill, and a barrier-strandplain system. Reservoir continuity is complex because, in addition to lateral facies variability, the major Oficina depositional systems were internally subdivided by high-frequency stratigraphic surfaces. These surfaces define times of intermittent lacustrine and marine flooding events that punctuated the fluvial and marginal marine sedimentation, respectively. Syn and post depositional faulting further disrupted reservoir continuity. Trends in fluid flow established from initial fluid levels, response to recompletion workovers, and pressure depletion data demonstrated barriers to lateral and vertical fluid flow caused by a combination of reservoir facies pinchout, flooding shale markers, and the faults. Considerable reserve growth potential exists at Budare field because the reservoir units are highly compartment by the depositional heterogeneity and structural complexity. Numerous reserve growth opportunities were identified in attics updip of existing production, in untapped or incompletely drained compartments, and in field extensions.

Hamilton, D.S.; Raeuchle, S.K.; Holtz, M.H. [Bureau of Economic Geology, Austin, TX (United States)] [and others

1997-08-01

378

Reassessing the cultural and psychopharmacological significance of Banisteriopsis caapi: preparation, classification and use among the Piaroa of Southern Venezuela.  

PubMed

Recent attention to the monoamine oxidase inhibiting properties of Banisteriopsis caapi's harmala alkaloids has precluded a balanced assessment of B. caapi's overall significance to indigenous South American societies. Relatively little attention has been paid to the cultural contexts, local meanings and patterns of use of B. caapi among snuff-using societies, such as the Piaroa, who do not prepare decoctions containing N,N-dimethyltryptamine (DMT) admixtures. This article reviews the psychopharmacological literature on B. caapi in light of recent ethnographic work conducted among the Piaroa of southern Venezuela. Piaroa shamans use only B. caapi's cambium, identify at least five distinct varieties of B. caapi, and emphasise the plant's importance for heightening empathy. Some Piaroa people also attribute a range of extra-shamanic uses to B. caapi, including as a stimulant and hunting aid. In light of the psychopharmacological complexity of harmala alkaloids, and ethnographic evidence for a wide range of B. caapi uses,future research should reconsider B. caapi's cultural heritage and psychopharmacological potential as a stimulant and antidepressant-like substance. PMID:19004422

Rodd, Robin

2008-09-01

379

[Detection and differentiation of Entamoeba histolytica and Entamoeba dispar by polymerase chain reaction in a community in Zulia State, Venezuela].  

PubMed

Differential identification of Entamoeba histolytica and Entamoeba dispar is essential for both appropriate patient treatment and epidemiological purposes. To determine the prevalence of these amoeba infections in Santa Rosa de Agua (Maracaibo, Zulia State, Venezuela), a PCR assay using specific primers for each species was standardized and applied. 204 stool samples were analyzed through direct microscopic examination with SSF (0.85%) and lugol, formol-ether concentration, and PCR. Under direct microscopy, 42 individuals (20.58%) presented the E. histolytica/E. dispar complex. Meanwhile PCR showed 47 positive cases for these amoebas: 22 E. histolytica (10.78%), 16 E. dispar (7.84%), and 9 (4.41%) mixed infections. There was no significant difference in the presence of E. histolytica and/or E. dispar according to either gender or age. There were no cases of these amoebas in children under 2 years of age. Observed frequency of E. histolytica (31/204) shows the endemic nature of amoeba infection in this community. PMID:19180297

Rivero, Zulbey; Bracho, Angela; Calchi, Marinella; Díaz, Iris; Acurero, Ellen; Maldonado, Adriana; Chourio, Glenis; Arráiz, Nailet; Corzo, Gilbert

2009-01-01

380

Density estimates of the domestic vector of Chagas disease, Rhodnius prolixus Stål (Hemiptera: Reduviidae), in rural houses in Venezuela.  

PubMed Central

We reported the use of the timed manual method, routinely employed as an indicator to the relative abundance of domestic triatomine bugs, to estimate their absolute density in houses. A team of six people collected Rhodnius prolixus Stål bugs from the walls and roofs of 14 typical palm-leaf rural houses located in Cojedes, Venezuela, spending 40 minutes searching in each house. One day after these manual collections, all the houses were demolished and the number of triatomine bugs were identified by instar and counted. Linear regression analyses of the number of R. prolixus collected over 4 man-hours and the census counts obtained by house demolition indicated that the fit of the data by instar (stage II--adult) and place of capture (roof versus palm walls versus mud walls) was satisfactory. The slopes of the regressions were interpreted as a measure of "catchability" (probability of capture). Catchability increased with developmental stage (ranging from 11.2% in stage II to 38.7% in adults), probably reflecting the increasing size and visibility of bugs as they evolved. The catchability on palm wall was higher than that for roofs or mud walls, increasing form 1.3% and 3.0% in stage II to 13.4% and 14.0% in adults, respectively. We reported, also, regression equations for converting field estimates of timed manual collections of R. prolixus into absolute density estimates. Images Fig. 1 PMID:7614667

Rabinovich, J. E.; Gürtler, R. E.; Leal, J. A.; Feliciangeli, D.

1995-01-01

381

Mesozoic-Early Paleogene Paleogeography of Venezuela/Trinidad and its implications for Caribbean/South America plate interaction  

SciTech Connect

We present paleogeographic reconstruction illustrating Jurassic-Early Cretaceous passive margin development along northern South America, followed by Late Cretaceous-Middle Eocene convergence between the Caribbean and South America plates. The maps support the model of in-situ origin of the Caribbean Plate. To construct the map's information from northern allochthonous units was combined with that from autochthonous units in the south. Allochthons comprise olistostromes, within upper Cretaceous-lower Paleogene flysch deposits, and upper Jurassic-lower Cretaceous metasediments in the Caribbean Mountains. In addition, northward tectonic escape of the Maracaibo Block and shortening resulting from plate collision were restored. The Late Cretaceous-Middle Eocene climax of Caribbean-South America plate collision was coeval from western Venezuela to Trinidad. Shortening juxtaposed rocks of disparate origins. However, the association of oceanic/volcanic elements with shelf deposits shows that the former were related to opening of the Caribbean and development of the Mesozoic passive margin of northern South America rather than originating in the Pacific. Since the late Eocene, plate interaction has been eastward migrating, dextral relative movement.

James, K.H.; Rigby, S.M.

1993-02-01

382

The relationship between mud volcanoes, petroleum migration and accretionary prisms: Lessons from the Caucasus, the Australian margin and Venezuela  

SciTech Connect

Mud volcanoes have been widely documented in areas of overpressure where explosive expansion of trapped methane has occurred during argillokinesis. In an area with high sedimentation rate, such as the Gulf of Mexico, there may be no time for fine-grained sediment to de-water before being covered by impermeable material. In an accretionary wedge this process is complicated by overthrusting of off-scraped material which increases the overburden pressure and provides many more avenues for the migration of fluids through the system. In some cases, such as is seen in the Caribbean, the fluids may escape directly to the surface (or seabottom) through high permeability beds. When this happens there may be no diapirism. In other cases, such as in Venezuela, the forearc may be the site of rapid, laterally-derived, sedimentation, and fluids from the overthrusted rocks may be forced to escape through several kilometers of recent deltaic sediments. Since these fluids may include petroleum, this has obvious exploration potential. If there are no suitable reservoir rocks, such as in Timor, there may be no commercial accumulations. However, many giant fields are associated, world-wide, with mud volcanoes, such as those in Azerbaijan.

Ware, P. [Unocal, Sugar Land, TX (United States)

1996-08-01

383

Dynamics of Black Band Disease in a Diploria strigosa population subjected to annual upwelling on the northeastern coast of Venezuela  

NASA Astrophysics Data System (ADS)

Temporal variability of Black Band Disease (BBD) prevalence, incidence, recurrence, recovery and virulence was estimated in a Diploria strigosa population from an upwelling zone of Venezuela, for 1 year between August 2004 and August 2005. The sampling spanned both upwelling and non-upwelling seasons, and included three samplings, roughly 60 days apart, within each season. The negative effects of BBD epizootiology in the sampling population (El Mercado reef) were positively correlated with sea surface temperature (taken as an upwelling estimator). Disease prevalence, incidence and recurrence decreased significantly during upwelling, and the recovery rate increased. Contrary to expectations, tissue mortality did not decrease significantly during the upwelling season, remaining at 1.2 ± 0.7 mm day-1. BBD prevalence, and the ensuing rates of tissue mortality were higher than values previously reported for other Caribbean reefs, even during upwelling episodes, suggesting that nutrient enrichment of the local waters by upwelling counteracts the expected reductions of the disease prevalence and virulence due to the lower temperature. Colonies which had previously been infected with BBD were up to six times more susceptible to new infections than those which were not infected during the preceding 7 months, suggesting that the infected colonies never healed completely. The high variability between tissue mortality values among coral colonies also suggests that overall host health-status may alter susceptibility to BBD infections.

Rodríguez, S.; Cróquer, A.

2008-06-01

384

Aerosol particle properties in the tropical free troposphere observed at Pico Espejo (4765 m a.s.l.), Venezuela  

NASA Astrophysics Data System (ADS)

The first long-term measurements of aerosol number and size distributions in South-American tropical free troposphere were performed from March 2007 until Mai 2009. The measurements took place at the high altitude Atmospheric Research Station Alexander von Humboldt. The station is located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Aerosol size distribution and number concentration data was obtained with a custom-built Differential Mobility Particle Sizer (DMPS system) and a Condensational Particle Counter (CPC). The analysis of the annual and diurnal variability of the tropical free troposphere (FT) aerosol focused mainly on possible links to the atmospheric general circulation in the tropics. Considerable annual and diurnal cycles of the particle number concentration were observed. Highest total particle number concentrations were measured during the dry season (519±613 cm-3), lowest during the wet season (318±194 cm-3). The more humid FT contained generally higher aerosol particle number concentrations (573±768 cm-3 during dry season, 320±195 cm-3 during wet season) than the dry FT (454±332 cm-3 during dry season, 275±172 cm-3 during wet season), indicating the importance of convection for aerosol distributions in the tropical FT. The diurnal cycle in the variability of the particle number concentration was mainly driven by local orography.

Schmeißner, T.; Krejci, R.; Ström, J.; Birmili, W.; Wiedensohler, A.; Hochschild, G.; Gross, J.; Hoffmann, P.; Calderon, S.

2010-11-01

385

Effect of Environmental Disturbance on the Population of Sandflies and Leishmania Transmission in an Endemic Area of Venezuela  

PubMed Central

The exploitation of new wilderness areas with crops is increasing and traditional crop substitution has been modified by new more productive crops. The results show the anthropogenic disturbance effect on the sandflies population and Leishmania transmission in endemic areas of Venezuela. Three agroecosystems with variable degrees of ecological disturbance, forest (conserved), cacao (fragmented), and orangery (disturbed), were selected. Four methods to sandfly capture were used; the specimens were identified and infected with Leishmania. Diversity, population structure, ANOVA, Tukey test, and simple correlation analysis were carried out. Shannon traps were able to capture 94.7% of the total sandflies, while CDC light traps, Sticky traps, and direct suction just captured 2.2%, 1.2%, and 0.9%, respectively. The results showed the effect of ecological disturbance degree on the composition of sandflies and population structure, revealing a dominance level increased but decreased on the diversity and richness of sandflies species in the greatest ecological disturbance area in relation to areas with less organic disturbance. Environments more disturbed cause adaptability of certain species such as Lutzomyia gomezi and Lutzomyia walkeri. These changes on the composition of sandflies population and structure emerging species could cause increasing of leishmaniasis transmission. PMID:24949018

Nieves, Elsa; Oraá, Luzmary; Rondón, Yorfer; Sánchez, Mireya; Sánchez, Yetsenia; Rojas, Masyelly; Rondón, Maritza; Rujano, Maria; González, Nestor; Cazorla, Dalmiro

2014-01-01

386

A new Dasypodini armadillo (Xenarthra: Cingulata) from San Gregorio Formation, Pliocene of Venezuela: affinities and biogeographic interpretations.  

PubMed

We describe Pliodasypus vergelianus gen. et sp. nov., a Dasypodini armadillo from the middle Pliocene of Venezuela (Vergel Member, San Gregorio Formation). Although scarce, the remains are remarkable because of their geochronologic proximity to the main phase of Great American Biotic Interchange (GABI). The cladistic analysis conducted reveals that Pliodasypus groups with Dasypus and both are sister taxa of Propraopus, whereas Anadasypus is at a basal position. With respect to the records of tribe Dasypodini, after its oldest representative (Anadasypus, middle and late Miocene), the chronologically subsequent form is Pl. vergelianus (middle Pliocene), followed by Dasypus bellus in higher northern latitudes (late Pliocene), and then by widespread occurrences in the Pleistocene of North America (D. bellus) and South America (Propraopus, Dasypus punctatus, and Dasypus novemcinctus). Thus, we infer that Dasypus differentiated in the late Pliocene at low latitudes in the northern South America. It leads to two alternative hypotheses of dispersal: (a) some early Dasypus remained cryptically in South America until the Pleistocene, whereas others dispersed to North America between 2.2 and 2.7 Ma, or (b) they dispersed to North America subsequently to the emersion of the Panamanian isthmus and D. bellus differentiated there; later, during the Pleistocene, D. bellus entered South America and experienced speciation. The same process of re-ingression has been proposed to other xenarthrans, breaking with the traditional assumption that the GABI was unidirectional. PMID:24414134

Castro, Mariela C; Carlini, Alfredo A; Sánchez, Rodolfo; Sánchez-Villagra, Marcelo R

2014-02-01

387

NORMAS GERAIS PARA INGRESSO COMO PORTADOR DE DIPLOMA DE  

E-print Network

1 NORMAS GERAIS PARA INGRESSO COMO PORTADOR DE DIPLOMA DE GRADUA��O (BRASIL) PERÍODO 2013.2 PRAZO PORTADOR DE DIPLOMA DE GRADUA��O DO BRASIL I­DAS CONDI��ES Portadores de Diploma de Graduação de Cursos; - Certificado de Dispensa de Incorporação; - CPF; Se candidato estrangeiro: - Certificado de Concl

388

El teatro como reflexión colectiva: Conversación con Sergio Corrieri  

E-print Network

SPRING 1983 51 El teatro como reflexión colectiva: Conversación con Sergio Corrieri Gerardo Luzuriaga Sergio Corrieri es el director del renombrado Teatro Escambray, fundado por él y otros teatristas de La Habana en 1968 en la región del... propios del subdesarrollo. La superstición, por ejemplo, muy extendida en nuestras zonas rurales; el reparo del campesino, sus dudas ante la colectivización del trabajo agrícola, ante el hecho de unir sus esfuerzos con los de otros campesinos, y en...

Luzuriaga, Gerardo

1983-04-01

389

Petrography and U-Pb Zircon Geochronology of Geological Units of the Mesa de Cocodite, Península de Paraguaná, Venezuela  

NASA Astrophysics Data System (ADS)

Several continental crust units crop out in The Mesa de Cocodite, central Paraguaná Peninsula, Northwestern Venezuela, including a newly mapped quartz-feldspar gneiss that intruded the El Amparo Pluton, a major low-graded metamorphic unit of Permian age. It is unconformably overlying by Late Jurassic phyllites of the Pueblo Nuevo Formation. All these units are cross-cut by narrow dykes. This contribution focuses on the petrography and LA-ICP-MS U-Pb zircon dating of the igneous units, with the aim of constraining magmatism and its tectonic significance in the area. The quartz-feldspar gneiss consists of albite, bluish-smoked quartz, muscovite-chlorite, epidote and zircon. The enclosing El Amparo Pluton is typically a coarse-grained and thick-banded metagranodiorite, containing andesine, quartz, hornblende, epidote, K-feldspar, biotite, chlorite, titanite and zircon. The younger dykes consist of fine-grained, porphyritic hornblende diorites that contain numerous hornblende phenocrysts. The main minerals are andesine, hornblende, quartz, and chlorite. Accessory minerals include zircon, epidote and opaques. A felsic gneiss xenolith collected from the dykes contain quartz, K-feldspar, chlorite, epidote, albite and zircon. Zircon population in the quartz-feldspar gneiss displays a discordia trend, ranging in age from 1050-750 Ma but mostly around 950-900 Ma, which may represent a peak high-grade metamorphism in the area. The El Amparo Pluton provides a concordant Permian age (271.3±6.5 Ma), which is comparable with previous reported U-Pb ages in titanite. Because the porphyry dykes cross-cut all the units in the area, they should be post-Late Jurassic in Age; however, all dated zircons from the dykes are in the range of 1200-750 Ma. The absence of younger ages can be attributed to either formation during a relatively low temperature magmatic event, which generated very narrow younger zircon rims only and thus undetectable with the technique used, or a completely lack of newly generated outer zones due to quick cooling. The emplacement age for the dykes may be early Cenozoic, as for similar basement rocks from the Gulf of Venezuela and the Guajira Peninsula. A felsic-gneiss xenolith enclosed in the dykes contains inherited Proterozoic zircons (1200-950 Ma) with rims of Permian age (270.2±4.1 Ma). Thus, the inherited older ages detected in the feldspar-gneiss unit, the later dykes, and the xenolith indicate the occurrence of Grenvillian crust in Northwestern South America. The Permian ages obtained in the Paraguaná Peninsula are similar to ages reported for the Mérida Andes, Santa Marta Massif, Perijá Range, Orchila Island, northern part of the Maracaibo Basin (Toas Island), northwestern Falcon Basin. Therefore, the Permian magmatic event may have been related to an active margin during the construction of Pangaea, caused by the subduction of oceanic crust under the northwestern corner of South America.

Mendi, D.; Baquero, M. L.; Oliveira, E. P.; Urbani, F.; Pinto, J.; Grande, S.; Valencia, V.

2013-05-01

390

Organic petrology of Paleocene Marcelina Formation coals, Paso Diablo mine, western Venezuela: Tectonic controls on coal type  

USGS Publications Warehouse

About 7??Mt of high volatile bituminous coal are produced annually from the four coal zones of the Upper Paleocene Marcelina Formation at the Paso Diablo open-pit mine of western Venezuela. As part of an ongoing coal quality study, we have characterized twenty-two coal channel samples from the mine using organic petrology techniques. Samples also were analyzed for proximate-ultimate parameters, forms of sulfur, free swelling index, ash fusion temperatures, and calorific value. Six of the samples represent incremental benches across the 12-13??m thick No. 4 bed, the stratigraphically lowest mined coal, which is also mined at the 10??km distant Mina Norte open-pit. Organic content of the No. 4 bed indicates an upward increase of woody vegetation and/or greater preservation of organic material throughout the life of the original mire(s). An upward increase in telovitrinite and corresponding decrease in detrovitrinite and inertinite illustrate this trend. In contrast, stratigraphically higher coal groups generally exhibit a 'dulling upward' trend. The generally high inertinite content, and low ash yield and sulfur content, suggest that the Paso Diablo coals were deposited in rain-fed raised mires, protected from clastic input and subjected to frequent oxidation and/or moisture stress. However, the two thinnest coal beds (both 0.7??m thick) are each characterized by lower inertinite and higher telovitrinite content relative to the rest of Paso Diablo coal beds, indicative of less well-established raised mire environments prior to drowning. Foreland basin Paleocene coals of western Venezuela, including the Paso Diablo deposit and time-correlative coal deposits of the Ta??chira and Me??rida Andes, are characterized by high inertinite and consistently lower ash and sulfur relative to Eocene and younger coals of the area. We interpret these age-delimited coal quality characteristics to be due to water availability as a function of the tectonic control of subsidence rate. It is postulated that slower subsidence rates dominated during the Paleocene while greater foreland basin subsidence rates during the Eocene-Miocene resulted from the loading of nappe thrust sheets as part of the main construction phases of the Andean orogen. South-southeastward advance and emplacement of the Lara nappes during the oblique transpressive collision of the Caribbean and South American tectonic plates in the Paleocene was further removed from the sites of peat deposition, resulting in slower subsidence rates. Slower subsidence in the Paleocene may have favored the growth of raised mires, generating higher inertinite concentrations through more frequent moisture stress. Consistently low ash yield and sulfur content would be due to the protection from clastic input in raised mires, in addition to the leaching of mineral matter by rainfall and the development of acidic conditions preventing fixation of sulfur. In contrast, peat mires of Eocene-Miocene age encountered rapid subsidence due to the proximity of nappe emplacement, resulting in lower inertinite content, higher and more variable sulfur content, and higher ash yield.

Hackley, P.C.; Martinez, M.

2007-01-01

391

New neotropical sebacinales species from a Pakaraimaea dipterocarpacea forest in the Guayana Region, Southern Venezuela: structural diversity and phylogeography.  

PubMed

Pakaraimaea dipterocarpacea, a member of the Dipterocarpaceae endemic in the Guayana region, is associated with a diverse community of ectomycorrhizal (ECM) fungi. Amongst the 41 ECM fungal species detected in a 400 m2 P. dipterocarpacea ssp. nitida plot in Southern Venezuela, three species belonged to the Sebacinales. We tested whether ECM anatomotype characterization can be used as a feasible element in an integrative taxonomy in this diverse fungal group, where the relevance of fruitbody morphology for species delimitation seems limited. Using a combination of ECM morpho-anatomical characterizations and phylogenetic analyses based on nuclear ITS and LSU sequences, we report three new species. The main distinguishing features of Sebacina guayanensis are the yellowish cell walls together with conspicuous undifferentiated, uniform compact (type B) rhizomorphs. Staghorn-like hyphae are characteristic of S. tomentosa. The combination of clusters of thick-walled emanating hyphae, including hyphae similar to awl-shaped cystidia with basal dichotomous or trichotomous ramifications, and the presence of type B rhizomorphs were characteristic of a third, yet unnamed species. The three species belong to three different, possibly specifically tropical clades in Sebacinales Group A. The geographic distribution of phylogenetically related strains was wide, including a Dicymbe forest in Guyana and an Ecuadorian rainforest with Coccoloba species. We show that ECM morpho-anatomy can be used, in combination with other analyses, to delineate species within Sebacinales Group A. In addition to phylogenetic information, type B rhizomorphs observed in different Sebacinales clades have important ecological implications for this fungal group. The phylogeography of Sebacinales suggests that dispersion and host jump are important radiation mechanisms that shaped P. dipterocarpacea ECM fungal community. This study emphasizes the need for more sequence data to evaluate the hypothesis that phylogeographic relationships between neo- and paleotropical ECM fungal species could be attributed to the vicariance of cross-continental hosts such as the Dipterocarpacae. PMID:25072467

Moyersoen, Bernard; Wei?, Michael

2014-01-01

392

Present-day deformation along the El Pilar Fault in eastern Venezuela: Evidence of creep along a major transform boundary  

NASA Astrophysics Data System (ADS)

The right-lateral strike-slip El Pilar Fault is one of the major structures that accommodate the relative displacement between the Caribbean and South-America Plates. This fault, which trends East-West along the northeastern Venezuela margin, is a seismogenic source, and shows numerous evidence for active tectonics, including deformation of the Quaternary sediments filling the Cariaco Gulf. Because the main El Pilar Fault strand belongs to a set of strike-slip faults and thrusts between the stable Guyana shield (South) and the Caribbean oceanic floor (North), a GPS network was designed and installed to measure the relative motion of the El Pilar Fault and other faults. The results obtained from the comparison of 2003 and 2005 surveys indicate: (i) a lack of significant displacement (especially shortening) in the Serrania del Interior (Neogene cordillera overthrusted above the Guyana craton), (ii) an eastward displacement (relative to fixed south America plate) up to 22 mm/year of benchmarks located north of the El Pilar Fault. Velocities simulations using dislocations in an elastic half-space show: (1) the concentration along the El Pilar Fault of the whole Caribbean-South America relative displacement, (2) the existence of an important component of aseismic displacement along the upper part of the El Pilar Fault. Between 12 km depth and the surface, only 40% of displacement is locked for the western segment and 50% for the eastern segment. This last phenomenon may be related to the existence of serpentinite lenses along the fault zone as observed for segments of San Andreas and North Anatolian faults.

Jouanne, François; Audemard, Franck A.; Beck, Christian; Van Welden, Aurélien; Ollarves, Reinaldo; Reinoza, Carlos

2011-05-01

393

Tidal currents in the Gulf of Paria (Venezuela) and their effects on the morphology of the bottom  

SciTech Connect

The Gulf of Paria, situated between the northeastern coast of Venezuela and the island of Trinidad, covers an area of about 7,200 square kilometers with shallow depths, normally inferior to 25 meters. The noticeable exception is the Gueiria trough with maximum depths exceeding 45 meters. The resulting tidal currents reach maximum velocities well above 1.5 m/s, capable of eroding the fine silty sediments if estuarine or deltaic origin present in the upper portions of the sub-bottom strata. The existing seismic and tectonic data of the Gulf of Paria suggest the presence of a fault pattern in an east-west direction, related to the dextral relative movement between the Caribbean and South American tectonic plates, so that the Gueiria trough origin has been related to this fault pattern. However, recent shallow geophysical data show absence of fault races in the upper sub-bottom strata of the Gueiria trough area, so that this must have been excavated by the tidal currents, which flow in alternating east-west directions with maximum surface velocities exceeding 1.4 m/s. The presence of strata of gravel controlled the erosion and resulted in the final morphology of the trough. This estuarine circulation pattern of the Gulf of Paria dictates particular requirements for pipeline laying, especially in the trough area and where the bottom is made of coarse gravely material, since the currents are strong, have alternating directions, but will probably not cause natural burial of the pipeline, because of the coarse sediment of the bottom.

Marcucci, E.; Soto, R.E.; Font, J.B. [Incostas, Caracas (Venezuela)

1996-12-01

394

[Disease in scleractinian corals: a new problem in the reef at Cayo Sombrero, Morrocoy National Park, Venezuela?].  

PubMed

At the beginning of 1996 coral reefs in Morrocoy National Park, Venezuela, suffered an unprecedented mass mortality event. As a consequence, live coral cover dropped to 2-10%. One of the few reefs that kept live coral cover over 35% was Cayo Sombrero; nonetheless, the presence of some coral diseases has been detected within the past 2 years, representing a new source of coral mortality. Due to this situation, this study started a monitoring program on the incidence of coral diseases and syndromes in the reef of Cayo Sombrero. The CARICOMP protocol was used in order to evaluate reef health. Ten parallel band-transects (20 x 2m) where established at two depth intervals: Five between 3-8 m and five between 8-12 m, and the frequency of both, healthy and unhealthy colonies of each coral species was recorded along each band transect. In addition to other sources of coral damage (predation, siltation, etc), significant differences in disease incidence between the two depths intervals were tested with a Kruskall-Wallis test. The main problems observed were coral diseases such as yellow band (4.2%), dark spots (1.61%) and white plague-II (1.4%), mainly affecting Montastraea faveolata, M. annularis and Siderastrea siderea. Siltation, affecting massive colonies, such as Colpophyllia natans and Diploria strigosa; algae overgrowth, predation, anchor damage, and bleaching. Significant differences were found in the incidence of unhealthy (Kruskall-Wallis, p < 0.05) bleached (Kruskall-Wallis, p < 0.05) and colonies affected by siltation (Kruskall-Wallis, p < 0.05). More than 60% of the 585 coral colonies surveyed at both depths were found to be healthy, indicating that the Cayo Sombrero reef is still in good conditions compared to other localities in the Park. This study stresses the need to conduct early monitoring programs that survey coral disease incidence as a source of mortality for this coral reef. PMID:15264568

Cróquer, Aldo; Bone, David

2003-06-01

395

A High-Resolution Oxygen Isotope Record for the Cariaco Basin, Venezuela Over the Last 6000 Years  

NASA Astrophysics Data System (ADS)

Oxygen isotope records of three species of planktonic foraminifera (Globigerinoides ruber (pink), Globigerina bulloides and Neogloboquadrina dutertrei) from the Cariaco Basin, Venezuela were used to construct a high-resolution climate record for the Caribbean region for the mid to late Holocene. Our results indicate decreases in sea surface temperatures and/or increases in salinity in the basin at least four times over the last 4000 years (at ~3800-3200, 2800-2500, 2200-2000, and after 650 cal. yrs. B.P.). These events are coincident with high stands of Lake Titicaca, Bolivia/Peru suggesting a similar forcing mechanism. Paleoclimate records from the circum-Caribbean indicate arid conditions commenced in this region between about 3600-3200 cal. yrs. B.P.. This corresponds to a decrease in the ? 18O of G. ruber (pink) and decreases in the ? 18O differences between G. bulloides - G. ruber (pink) and N. dutertrei - G. ruber (pink). In addition, the deep dwelling planktonic foraminifera species Globorotalia crassaformis migrates into Cariaco Basin at about 3500 cal. yrs. B.P.. Taken together these data indicate colder sea surface temperatures and a shallow thermocline, possibly due to increased upwelling. Increased evaporation at this site would also result in higher G. ruber (pink) ? 18O values. Dry conditions in the circum-Caribbean tropics and wetter conditions in the Altiplano of Bolivia and Peru and the Amazon basin during the mid to late Holocene are consistent with a southward displacement of the Inter-Tropical Convergence Zone (ITCZ) resulting in decreased precipitation and increased trade wind intensity in the Cariaco Basin.

Tedesco, K.; Thunell, R.; Tappa, E.

2001-12-01

396

Prediction and verification of possible reef-fish spawning aggregation sites in Los Roques Archipelago National Park, Venezuela.  

PubMed

This study attempts to predict and verify possible spawning aggregation sites and times in the Los Roques Archipelago National Park, Venezuela, based on physical reef characteristics and the knowledge of experienced local fishermen. Three possible aggregation sites were selected for monitoring based on satellite images, low-cost bathymetric mapping and interviews with experienced local fishermen. Abundances and sizes of 18 species that are known to form reproductive aggregations were monitored at these sites using underwater visual census for 7 days after each full moon from February to August, 2007. While spawning events were not observed, possible indirect evidence of spawning aggregations was found for Lutjanus analis at Cayo Sal and Boca de Sebastopol, Lutjanus apodus at Cayo Sal, Lutjanus cyanopterus at Cayo Sal and Piedra La Guasa and Epinephelus guttatus at Bajo California and Cayo de Agua. Additionally, indirect evidence was identified for the past existence of a spawning aggregation of Epinephelus striatus in the northern part of the archipelago, which may have been eliminated by overfishing c.15 years ago. Bathymetric mapping showed that the shelf edge at sites monitored in this study was shallower than at spawning aggregation sites in other parts of the Caribbean, and that sites were not proximal to deep water. While this study does not prove the existence or locations of spawning aggregations of reef fishes in the archipelago, it does add insight to a growing understanding of generalities in the relationship between seafloor characteristics and the locations of transient reef-fish spawning aggregations in the Caribbean. PMID:20840614

Boomhower, J; Romero, M; Posada, J; Kobara, S; Heyman, W

2010-09-01

397

Biological and phylogenetic characterization of a genotype VII Newcastle disease virus from Venezuela: efficacy of field vaccination.  

PubMed

Here we report the biological and molecular characterization of a virulent genotype VII Newcastle disease virus (NDV) circulating in Venezuela and the assessment of the vaccination efficacy under field conditions compared to controlled rearing conditions. Biological pathotyping showed a mean embryo dead time of 50 h and an intracerebral pathogenicity index of 1.86. Sequence-based phylogenetic analysis demonstrated that the virus belongs to genotype VII in class II (a genotype often found in Asia and Africa), representing the first report of the presence of this genotype in the continent of South America. A vaccine-challenge trial in commercial broilers reared in fields or in a experimental setting included dual (live/killed) priming of 1-day-old chicks plus two live NDV and infectious bursal disease virus (IBDV) field vaccinations at days 7 and 17, followed by a very stringent genotype VII NDV challenge at day 28. Serology for NDV and IBDV, bursal integrity, and protection against NDV lethal challenge were assessed. At 28 days, field vaccinates showed significantly lower NDV (1,356 versus 2,384) and higher IBD (7,295 versus 1,489) enzyme-linked immunosorbent assay (ELISA) antibody titers than the experimentally reared birds. A lower bursal size and bursa-body weight ratio (P < 0.05) and higher bursa lesion score were also detected in the field set. Only 57.1% of field vaccinates survived the lethal challenge, differing (P < 0.05) from 90.5% survival in the experimental farm. Overall, results confirmed the presence of the genotype VII viruses in South America and suggest that field-associated factors such as immunosuppression compromise the efficacy of the vaccination protocols implemented. PMID:22238433

Perozo, Francisco; Marcano, Rosmar; Afonso, Claudio L

2012-04-01

398

Stochastic modeling of lower delta and coastal plain reservoir in the Eocene-Misoa Formation, Ceuta Field, Venezuela  

SciTech Connect

Stochastic modeling technique minimizes uncertainties in the values used for reservoir parameters and this reduces the risk in reservoir management practices. This technique was successfully employed in modeling south Ceuta field in Venezuela which will be subjected to secondary recovery due to significant pressure decline. The Lower Misoa reservoir is divided into five sedimentological units; the upper three units am characterized by distributary channels, mouth bars and crevasse plains, whereas the lower units we deposited in coastal plain bars and tidal channels. The deterministic data was used to build a stochastic model with HERESIM simulator which employs a Gaussian Truncated Technique. Eight stochastic realizations were generated and the geometry and the quality of each sedimentary unit was defined for every realization. A quantitative flow unit model was developed in a grid of 125 x 60 x 280 uniform blocks, the dimensions of each block being 180 m square and .3048 m in height. The two uppermost units exhibit better quality rocks. Eighty percent of this interval contains facies with good lateral continuity, ranging from 1-3 km within the coastal bar deposits, and from 1-2 km within the tidal channels. The quality of the deposits degrades towards southwest and West. Permeability ranges from 100 to 480 md in the best units and from 31 to 250 md in the lower units. Reservoir porosity varies from 10-14%. An interface between HERESIM and the ECLIPSE reservoir simulator was developed to establish a dynamic fluid flow simulation. Four out of the eight realizations produced excellent match for the pressure-production history without any need for data manipulation. The technique therefore, could save approximately 60% of history match time.

Azpiritxaga, I.; Hernandez, E.; Vivas, M. [and others

1995-08-01

399

Cenozoic oblique collision of South American and Caribbean plates: New evidence in the Coastal Cordillera of Venezuela and Trinidad  

SciTech Connect

The hinterland of the Caribbean Mts. orogen in Trinidad and Venezuela contains schist and gneiss whole protoliths are wholly or partly of continental provenance. The hinterland lies between the foreland thrust belt and terranes. The terranes are alien to continental South America (SA) and may have proto-Caribbean or Caribbean plate origins. The hinterland rocks were widely thought to come from sediments and granitoids of Mesozoic protolithic ages and to be of Cretaceous metamorphic age. Such rocks are now know to be of at least two or more types, as follows: (1) low grade, protoliths of pre-Mesozoic basement and shelfal cover of uncertain age range, inboard locus, Oligocene to mid-Miocene metamorphic ages younging eastward (Caracas, Paria, and Northern Range belts), and (2) higher grade including high P/T, varies protoliths of uncertain age range, Cretaceous and ( )early Paleogene metamorphic ages (Tacagua, Araya, Margarita). The geometry, protoliths, structures, and metamorphic ages of type 1 parautochthoneity and an origin as a thickened wedge of crust-cored passive margin cover. The wedge grew by accretion between about 35 and 20 Ma during oblique transport toward the foreland. The diachroneity of metamorphism implies, as does the timing of foreland deformation, that the wedge evolved in a right-oblique collision between northern SA and terranes moving wholly or partly with the Caribbean plate since the Eocene. Type 2 rocks probably came with the terranes and are products of convergent zone tectonics, either in the proto-Caribbean plate. The hinterland boundaries are brittle thrusts that are out of sequence and imply progressive contraction from mid-Cenozoic to the present.

Speed, R.C. (Northwestern Univ., Evanston, IL (United States)); Russo, R.M. (Carnegie Institute of Washington (United States)); Foland, K.A. (Ohio State Univ., Columbus (United States))

1993-02-01

400

The southern margin of the Caribbean Plate in Venezuela: tectono-magmatic setting of the ophiolitic units and kinematic evolution  

NASA Astrophysics Data System (ADS)

The southern Caribbean Plate margin in Venezuela consists of a W-E elongated deformed belt, composed of several tectonic units dismembered along the northern part of the South America continental Plate since the Late Cretaceous. The present review, based on petrology and tectono-magmatic significance of each unit, makes it possible to define the main geotectonic elements and to reconstruct the paleogeographic domains from Late Jurassic to Tertiary: (a) Mid-Ocean Ridge Basalt (MORB) proto-Caribbean oceanic basin (Loma de Hierro Unit); (b) oceanic plateau (Dutch and Venezuelan Islands basement); (c) rifted continental margin (Cordillera de La Costa and Caucagua-El Tinaco Units) with Within Plate Tholeiitic (WPTh) magmatism; (d) an intra-oceanic subduction zone represented by Island Arc Tholeiitic (IAT) magmatism (Villa de Cura and Dos Hermanas Units) of Early Cretaceous age; (e) an Early Cretaceous ocean-continent subduction trench filled by melange (Franja Costera); (f) a new intra-oceanic subduction zone, represented by the tonalitic arc magmatism of Late Cretaceous age (Dutch and Venezuelan Islands). Regional tectonic constraints and coherent kinematic reconstruction suggest an original "near-Mid America" location of the Jurassic-Cretaceous "proto-Caribbean" oceanic realm. From Early to Late Cretaceous one sub-continental subduction with melanges (Franja Costera Unit) and two main stages of intra-oceanic arc magmatism are recorded in the so-called "eo-Caribbean" phases. The first consists of generally metamorphosed and deformed volcano-plutonic sequences with IAT affinity (Villa de Cura and Dos Hermanas Units), probably in relation to a southeastward-dipping subduction. The second is mainly represented by generally unmetamorphosed tonalitic intrusives cutting the oceanic plateau in the Dutch and Venezuelan Islands, and related to the new intra-oceanic subduction with reverse lithospheric sinking. The latter probably marked the onset of the Aves/Lesser Antilles arc system in the Late Cretaceous.

Giunta, Giuseppe; Beccaluva, Luigi; Coltorti, Massimo; Siena, Franca; Vaccaro, Carmela

2002-07-01

401

An extraordinary example of photokarren in a sandstone cave, Cueva Charles Brewer, Chimantá Plateau, Venezuela: Biogeomorphology on a small scale  

NASA Astrophysics Data System (ADS)

A distinctive suite of small-scale erosional forms that are oriented towards the light occur close to the entrance of Cueva Charles Brewer, a large cave in a sandstone tepui, in SE Venezuela. These are the third example of photokarren ever studied in the world, the other two being from Borneo and Ireland. They are the only photokarren ever described from sandstone, and the only example from a non-carbonate environment. The host rock is a poorly-lithified unit of the Precambrian quartz arenite of the Roraima Supergroup. The forms are all oriented towards the light at 30° regardless of rock surface orientation. The primary (negative) erosional form is the tube. Coalescence of tubes results in the positive remnant forms of rods, pinnacles, and cones. The final stage is a bumpy, wavy surface of degraded cones. The size of the features varies with erosion rate, and details of the form vary with development stage. The main population averages 4.4 cm in depth, with 55% of the surface eroded. This is divided into 10% tubes, 70% rods, 10% cones, 5% linear valley and 5% wavy lowland. The micro-ecosystem includes many bacteria, diatoms, red algae, green algae, liverworts, and oribatid mites, but, surprisingly, no cyanobacteria. The presence of a surface biofilm inside the forms but not on the remnant rock surface and, in the non-degraded forms, the direct relationship of biomass with depth suggests that biological activity is the dominant control on development. In addition, direct bacterial corrosion was noted. These same features occur to varying extents in the photokarren of Borneo and Ireland, and the model for development that we present provides a unifying theory for all photokarren. (This study also includes the first published petrographic analysis of uppermost unit of the Mataui Formation).

Lundberg, J.; McFarlane, D. A.; Brewer-Carias, C.

2010-09-01

402

An investigation of the probability of occurrence of dry periods during the rainy season in the grassy highlands of Western Venezuela  

E-print Network

of this thes1s. To Ing. R. Mart1nez of the "Vicerrectorado de Produccion Agricola, Un1versidad Nacional Experimental de los Llanos Occidentales, Ezequiel Zamora, " Guanare, Venezuela, for prov1ding me with the climatological data used in this invest1gation...- out my graduate plan; also for his friendship. To the Vice-President of the "Vicerrectorado de Produccion Agricola de la Universidad Nacional Experimental de los Llanos Occidentales, Ezequiel Zamora" in the State of Portuguesa, Dr. P. J. Urriola M...

Quintana Gomez, Ramon Alfonso

1983-01-01

403

A new baseline for fascioliasis in Venezuela: lymnaeid vectors ascertained by DNA sequencing and analysis of their relationships with human and animal infection  

PubMed Central

Background Human and animal fascioliasis poses serious public health problems in South America. In Venezuela, livestock infection represents an important veterinary problem whereas there appear to be few human cases reported, most of which are passively detected in health centres. However, results of recent surveys suggest that the situation may be underestimated in particular areas. To obtain a baseline for future fascioliasis assessment, studies were undertaken by means of rDNA ITS-2 and ITS-1 and mtDNA cox1 sequencing to clarify the specific status of Venezuelan lymnaeids, their geographical distribution and fascioliasis transmission capacity, by comparison with other American countries and other continents. Results Results obtained completely change the lymnaeid scenario known so far. The relatively rich lymnaeid fauna of Venezuela has been proven to include (i) Lymnaea meridensis and L. neotropica as the only native members, (ii) L. cubensis and Pseudosuccinea columella introduced from the Caribbean area, and (iii) Galba truncatula and L. schirazensis introduced from the Old World. The absence of representatives of the stagnicoline and Radix groups is remarkable. Four species are fascioliasis vectors: G. truncatula, L. cubensis and L. neotropica, which have the capacity to give rise to human endemic areas, and P. columella, which is a source of animal infection and is responsible for the spread of disease. Vector capacity in the apparently highland endemic L. meridensis is to be confimed, although may be expected given its phylogenetic relationships. Similarly as elsewhere, the non-transmitting L. schirazensis has been confused with L. cubensis, also with G. truncatula and possibly with L. neotropica. Conclusions The new scenario leads to the re-opening of many disease aspects. In Venezuela, altitude appears to be the main factor influencing fascioliasis distribution. Human infection shows an altitude pattern similar to other Andean countries, although a differing highland/lowland impact on animal infection does not appear evident. The overlap of G. truncatula, L. cubensis and probably also L. neotropica in temperate and cold zones suggests a higher risk for human infection in mid and high altitude areas. A lymnaeid species mapping by means of DNA markers becomes a priority to determine human and animal fascioliasis distribution in Venezuela, owing to the importance of lymnaeid vectors in defining transmission and epidemiological patterns. PMID:21999170

2011-01-01

404

Valorisation of Como Historical Cadastral Maps Through Modern Web Geoservices  

NASA Astrophysics Data System (ADS)

Cartographic cultural heritage preserved in worldwide archives is often stored in the original paper version only, thus restricting both the chances of utilization and the range of possible users. The Web C.A.R.T.E. system addressed this issue with regard to the precious cadastral maps preserved at the State Archive of Como. Aim of the project was to improve the visibility and accessibility of this heritage using the latest free and open source tools for processing, cataloguing and web publishing the maps. The resulting architecture should therefore assist the State Archive of Como in managing its cartographic contents. After a pre-processing consisting of digitization and georeferencing steps, maps were provided with metadata, compiled according to the current Italian standards and managed through an ad hoc version of the GeoNetwork Opensource geocatalog software. A dedicated MapFish-based webGIS client, with an optimized version also for mobile platforms, was built for maps publication and 2D navigation. A module for 3D visualization of cadastral maps was finally developed using the NASA World Wind Virtual Globe. Thanks to a temporal slidebar, time was also included in the system producing a 4D Graphical User Interface. The overall architecture was totally built with free and open source software and allows a direct and intuitive consultation of historical maps. Besides the notable advantage of keeping original paper maps intact, the system greatly simplifies the work of the State Archive of Como common users and together widens the same range of users thanks to the modernization of map consultation tools.

Brovelli, M. A.; Minghini, M.; Zamboni, G.

2012-07-01

405

La poesía como elemento de estructura dramática en Alfonsina  

E-print Network

la luz. La ciudad de Mendoza, ubicada a 1.100 km de la capital federal y al pie de la Cordillera de los Andes que la separa de Chile, tiene una larga tradición literaria en general y teatral en particular. Como zona de paso entre Buenos Aires y.... Víctima de una enfermedad incurable, se quitó la vida arrojándose al mar. Su poesía evoluciona desde el modernismo y el parnasianismo hasta los movimientos de vanguardia: La inquietud del rosal, El dulce daño, Irremediablemente, Languidez, Ocre y...

Navarette, José Francisco

1990-10-01

406

comoR: a software for disease comorbidity risk assessment  

PubMed Central

Background The diagnosis of comorbidities, which refers to the coexistence of different acute and chronic diseases, is difficult due to the modern extreme specialisation of physicians. We envisage that a software dedicated to comorbidity diagnosis could result in an effective aid to the health practice. Results We have developed an R software comoR to compute novel estimators of the disease comorbidity associations. Starting from an initial diagnosis, genetic and clinical data of a patient the software identifies the risk of disease comorbidity. Then it provides a pipeline with different causal inference packages (e.g. pcalg, qtlnet etc) to predict the causal relationship of diseases. It also provides a pipeline with network regression and survival analysis tools (e.g. Net-Cox, rbsurv etc) to predict more accurate survival probability of patients. The input of this software is the initial diagnosis for a patient and the output provides evidences of disease comorbidity mapping. Conclusions The functions of the comoR offer flexibility for diagnostic applications to predict disease comorbidities, and can be easily integrated to high–throughput and clinical data analysis pipelines. PMID:25045465

2014-01-01

407

Soil fluxes and atmospheric concentration of CO and CH4 in the Northern Part of the Guayana Shield, Venezuela  

NASA Astrophysics Data System (ADS)

Soil fluxes and atmospheric concentrations of CH4 and CO were measured in a scrub grass savanna in Venezuela, during October 1988. Soil flux measurements were also made in a nearby semideciduous forest. Emission of CH4 was observed from the "dry " savanna soils; emissions do not show any significant trend with the time of day and have an average of 3.5±5.0×1010 molecules cm-2 s-1. CO fluxes show a strong diurnal variation, with net emission during daytime and consumption during nighttime. Twenty-four-hour integrated soil fluxes give a small net emission of CO of 5.6×109 molecules cm-2 s-1 this result contrasts with previous net sink estimates given in the literature. Forest soils consume both CH4 and CO at rates of -5.0×1010 and -2.4×1011 molecules cm-2 s-1 respectively. Therefore, long-range forest degradation should produce an increase in the emission of CO and CH4 from these tropical soils. At the savanna site, higher atmospheric concentrations of CH4 and CO were observed during nighttime. Minimum concentrations, representative of boundary layer conditions, were observed during hours of high solar irradiation with values of 1.78±0.04 ppm and 224±61 ppb for CH4 and CO, respectively. Using the methane concentration increase inside the nocturnal mixing height, a total methane source of 4.9×1011 molecules cm-2 s-1 from the surface was calculated, showing that a significant dispersed source, likely from termites and/or small tracts of flooded soils, is present in the tropical savanna region. Extrapolating this value to the world savanna regions, an emission of 61 Tg CH4 is estimated, this is about 10% of the global source of methane. From chamber measurements a distinct nighttime soil consumption of CO was observed; however, the concentration remained fairly constant during the night, indicating a surface source of CO of the order of 5×1010 molecules cm-2 s-1. Even though anthropogenic sources cannot be ruled out completely, termites and vegetation emission are, most likely, the dispersed sources of CO in the savanna region.

Scharffe, Dieter; Hao, Wei Min; Donoso, Loreto; Crutzen, Paul J.; Sanhueza, Eugenio

1990-12-01

408

Geomorphological signature of the Pleistocene thin-skinned tectonics in the northern Maturín Foreland Basin, Eastern Venezuela  

NASA Astrophysics Data System (ADS)

The Eastern Venezuela foreland basin and the Serranía del Interior fold-thrust-belt were formed as a consequence of the oblique collision between Caribbean and South American plates. The foreland basin is divided into the Guárico sub-basin in the west and the Maturín sub-basin in the east. The Maturín sub-basin is geologically well known due to geological survey and structural-stratigraphic modeling motived by the hydrocarbon exploration. We focus here on Plio-Pleistocene deformations of the area that remain poorly understood. The study area stands on the northern edge of the Maturín sub-basin, in an area limited by the foothills of the Serranía del Interior to the north, and by the right lateral crustal Urica and San Francisco Faults to the west and east respectively. Between them, from the mountain to the deformation front, the thin-skinned tectonic wedge is mainly structured above the Pirital and Furrial thrust faults. The Pirital thrust fault involves a thick lithographic section that includes presumably pre-Cretaceous rocks whereas the Furrial Thrust is shallower and is associated with fault-bend-folds structures. We support that the Maturín sub-basin remains an area of active continental shortening in which a post-Pliocene peneplain surface has been deformed by folds, which are developed above buried reverse faults. We use the drainage patterns in this region to show active deformations that would be difficult to identify by other means. In particular we show how uplifts and tilts associated to fault activity alter the drainage pattern and the geometry of remnant terraces near Tarragona, San Felix, Punta de Mata, El Tejero and Jusepín zones. Given age, dip angles of the faults, and the vertical throw determined from the offset of the terrace and peneplain surfaces across the surface fault traces, we aim to estimate the cumulative shortening along the direction of tectonic transport and slip rates. Industrial seismic lines show that superficial deformations are not systematically connected to fault in depth. This raise the question (1) of the origin of the ongoing shortening in the tectonic wedge and (2) of the potentiality of a strain partitioning between thick-skinned and thin-skinned active deformations.

Fajardo, Atiria; Nivière, Bertrand; Aubourg, Charles; Hervouët, Yves; Wagner, Roberto; Regard, Vincent; Callot, Jean-Paul

2013-04-01

409

Prevalence of musculoskeletal disorders and rheumatic diseases in an urban community in Monagas State, Venezuela: a COPCORD study.  

PubMed

The aim of the study was to determine the prevalence of musculoskeletal disorders and rheumatic diseases in an urban community in Venezuela. We conducted a cross-sectional, community-based study using the COPCORD (Community Oriented Program for Control of Rheumatic Diseases) methodology in subjects older than 18 years. Positive cases were evaluated by rheumatologists. We surveyed 3,973 individuals (1,606 males and 2,367 females), with a mean age of 43.7 years (standard deviation (SD) 17.6). Mean duration of education was 8.9 years (SD 3.7), 79.2 % had a monthly income of?

Granados, Ysabel; Cedeño, Ligia; Rosillo, Celenia; Berbin, Sol; Azocar, Miriam; Molina, María Elena; Lara, Onelia; Sanchez, Gloris; Peláez-Ballestas, Ingris

2014-06-13

410

Water Soluble Organic Nitrogen in atmospheric aerosol samples from urban, sub-urban and pristine areas of Venezuela  

NASA Astrophysics Data System (ADS)

Concentrations of water soluble organic nitrogen (WSON) were determined in atmospheric total suspended particles (TSP) collected between September of 2005 and May of 2006, in an urban continental (Caracas, 10° 29' 09'' N, 66° 53' 48'' W), an urban coastal (Catia la mar, 10° 35' 47'' N, 67° 01' 45'' W), a sub-urban coastal (Osma, 10° 32' N, 67° 28' W), a suburban continental (Altos de Pipe, 10° 23' 41'' N, 63° 59' 10'' W), a pristine coastal (Isla de Aves, 15° 40' N, 63° 36' W) and a pristine continental (La Gran Sabana National Park, 5° 41' 30'' N, 61° 34' 20'' W) areas of Venezuela. TSP samples were collected using a Hi-Vol airborne particle sampler. TSP were impacted on a fiberglass filter pretreated under 400° C for 4 hours to minimize organic nitrogen contamination. Ultra sound water extractions of the sample filters were performed and their NH4+, NO2- and NO3- concentrations were determined by ion exchange liquid chromatography. The water extracts were UV digested and the nitrogen inorganic ions were analyzed after the UV exposure. WSON concentrations were calculated by the difference between the inorganic nitrogen concentrations before and after UV digestion. Ninety five percent of the aerosol samples collected in the suburban and pristine areas showed a WSON concentration range from 0.03 to 0.6 ?g/m3 whereas in urban areas the range was 0.21 to 1.09 ?g/m3. These concentration values are on the same order of magnitude than the previously found in other tropical and subtropical areas. The contribution of aerosol WSON to the total soluble nitrogen in the coastal urban, sub-urban and pristine areas ranged from 23 to 67%, while in Caracas was smaller (38±8%, n=5). Therefore, aerosol WSON provides an important source of nitrogen to these pristine and suburban ecosystems, which could potentially have implications on the nutrient cycling. There was a statistically significant linear correlation between the aerosol WSON and the water soluble inorganic nitrogen (WSIN) for the urban coastal, sub-urban and pristine zones (R2= 0.81, n=22). This correlation could be explained by a possible source of secondary water soluble organic aerosols derived by the reaction between biogenic volatile organic compounds (VOCs), such as isoprene, and nitrogen oxides (NOx) present in the atmosphere of these regions. Such correlation was not found in Caracas, possibly due to the fact that in this city the major source of VOCs is fossil fuel combustion which produces mostly non soluble aliphatic VOCs. These compounds could most likely produce low water soluble secondary organic nitrogen aerosols.

Canelon, R.; Giuliante, A.; Aguiar, G.; Ghneim, T.; Perez, T.

2007-12-01

411

[Substitution of native savanna by Pinus caribaea (Pinaceae) plantations in Venezuela: effect on parameters that indicated changes in soil carbon content].  

PubMed

A great extension (615,000 ha) of native savannas of the eastern plains of Venezuela have been replaced by plantations of Pinus caribaea var. hondurensis; however, only scarce information exists about the impact of this land use on carbon dynamics in soils. We studied the effect of temporal variability and the substitution on the total organic carbon (TOC), water-soluble carbon (WSC), microbial biomass C (Cmic), basal respiration (BR), microbial metabolic quotient (qCO2) and Cmic/Corg ratio. Selected chemical properties and biological parameters of soils were measured under 3 and 29 year old forest plantations of P. caribaea and an adjacent native savanna which was considered the control. At each site, nine soil composite samples were collected (0-10 cm depth). The studied parameters did not show a defined pattern in relation to temporal variability. Higher carbon preservation occurs in soil microbial biomass under pine plantations. The basal respiration rate and qCO2 suggests that there is a more efficient microbial carbon utilization in the plantations. The Cmic/Corg ratio shows that the microbial biomass has an important stock of soil carbon in pine plantations. The conversion of savannas to pine plantations can increase soil carbon in the eastern plains of Venezuela, but this must be balanced with the ecological importance of natural savannas ecosystems. PMID:19419100

Gómez, Yrma; Paolini, Jorge; Hernández, Rosa Mary

2008-12-01

412

Development of a Streptomyces venezuelae-Based Combinatorial Biosynthetic System for the Production of Glycosylated Derivatives of Doxorubicin and Its Biosynthetic Intermediates ? †  

PubMed Central

Doxorubicin, one of the most widely used anticancer drugs, is composed of a tetracyclic polyketide aglycone and l-daunosamine as a deoxysugar moiety, which acts as an important determinant of its biological activity. This is exemplified by the fewer side effects of semisynthetic epirubicin (4?-epi-doxorubicin). An efficient combinatorial biosynthetic system that can convert the exogenous aglycone ?-rhodomycinone into diverse glycosylated derivatives of doxorubicin or its biosynthetic intermediates, rhodomycin D and daunorubicin, was developed through the use of Streptomyces venezuelae mutants carrying plasmids that direct the biosynthesis of different nucleotide deoxysugars and their transfer onto aglycone, as well as the postglycosylation modifications. This system improved epirubicin production from ?-rhodomycinone by selecting a substrate flexible glycosyltransferase, AknS, which was able to transfer the unnatural sugar donors and a TDP-4-ketohexose reductase, AvrE, which efficiently supported the biosynthesis of TDP-4-epi-l-daunosamine. Furthermore, a range of doxorubicin analogs containing diverse deoxysugar moieties, seven of which are novel rhodomycin D derivatives, were generated. This provides new insights into the functions of deoxysugar biosynthetic enzymes and demonstrates the potential of the S. venezuelae-based combinatorial biosynthetic system as a simple biological tool for modifying structurally complex sugar moieties attached to anthracyclines as an alternative to chemical syntheses for improving anticancer agents. PMID:21602397

Han, Ah Reum; Park, Je Won; Lee, Mi Kyeong; Ban, Yeon Hee; Yoo, Young Ji; Kim, Eun Ji; Kim, Eunji; Kim, Byung-Gee; Sohng, Jae Kyung; Yoon, Yeo Joon

2011-01-01

413

Venezuela's Bolivarian Schools Project.  

ERIC Educational Resources Information Center

Discusses efforts by the Venezuelan government to improve the nation's school infrastructure through the Bolivarian Schools Project administered by the Ministry of Education, Culture and Sport. The project set educational principles which are guiding current school building efforts. (EV)

Diaz, Maria Magnolia Santamaria

2002-01-01

414

Venezuela: Lake Maracaibo  

Atmospheric Science Data Center

... path 8. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, ... acknowledgment: Clare Averill (Acro Service Corporation/Jet Propulsion Laboratory), David J. Diner (Jet Propulsion Laboratory), John V. ...

2013-04-18

415

Comparative amino acid sequence analysis of the major outer capsid protein (VP7) of porcine rotaviruses with G3 and G5 serotype specificities isolated in Venezuela and Argentina  

Microsoft Academic Search

Summary Seven porcine group A rotavirus strains isolated in Venezuela were shown to be antigenically related to serotype G3 (five strains) or to serotype G5 (two strains), whereas two strains isolated in Argentina were classified as serotype G5. The serological classification of eight of these strains was confirmed by sequence analysis of the gene encoding the VP7 glycoprotein. A high

M. Ciarlet; J. E. Ludert; F. Liprandi

1995-01-01

416

Earthquake source imaging by high-resolution array analysis at regional distances: the 2010 M7 Haiti earthquake as seen by the Venezuela National Seismic Network  

NASA Astrophysics Data System (ADS)

Back projection of teleseismic waves based on array processing has become a popular technique for earthquake source imaging,in particular to track the areas of the source that generate the strongest high frequency radiation. The technique has been previously applied to study the rupture process of the Sumatra earthquake and the supershear rupture of the Kunlun earthquakes. Here we attempt to image the Haiti earthquake using the data recorded by Venezuela National Seismic Network (VNSN). The network is composed of 22 broad-band stations with an East-West oriented geometry, and is located approximately 10 degrees away from Haiti in the perpendicular direction to the Enriquillo fault strike. This is the first opportunity to exploit the privileged position of the VNSN to study large earthquake ruptures in the Caribbean region. This is also a great opportunity to explore the back projection scheme of the crustal Pn phase at regional distances,which provides unique complementary insights to the teleseismic source inversions. The challenge in the analysis of the 2010 M7.0 Haiti earthquake is its very compact source region, possibly shorter than 30km, which is below the resolution limit of standard back projection techniques based on beamforming. Results of back projection analysis using the teleseismic USarray data reveal little details of the rupture process. To overcome the classical resolution limit we explored the Multiple Signal Classification method (MUSIC), a high-resolution array processing technique based on the signal-noise orthognality in the eigen space of the data covariance, which achieves both enhanced resolution and better ability to resolve closely spaced sources. We experiment with various synthetic earthquake scenarios to test the resolution. We find that MUSIC provides at least 3 times higher resolution than beamforming. We also study the inherent bias due to the interferences of coherent Green’s functions, which leads to a potential quantification of biased uncertainty of the back projection. Preliminary results from the Venezuela data set shows an East to West rupture propagation along the fault with sub-Rayleigh rupture speed, consistent with a compact source with two significant asperities which are confirmed by source time function obtained from Green’s function deconvolution and other source inversion results. These efforts could lead the Venezuela National Seismic Network to play a prominent role in the timely characterization of the rupture process of large earthquakes in the Caribbean, including the future ruptures along the yet unbroken segments of the Enriquillo fault system.

Meng, L.; Ampuero, J. P.; Rendon, H.

2010-12-01

417

10Be dating of river terraces of Santo Domingo river, on Southeastern flank of the Mérida Andes, Venezuela: Tectonic and climatic implications  

NASA Astrophysics Data System (ADS)

In this study, we discuss the first cosmogenic 10Be dating of river terraces located in the lower reaches of the Santo Domingo river (Southeastern flank of the Mérida Andes, Western Venezuela). The geomorphic observations and dating allowed the restoration of the temporal evolution of incision rate, which was analysed in terms of tectonic, climatic and geomorphic processes. The long-term incision rate in the area has been constantly around 1.1 mm/a over the last 70 ka. Taking into account the geologic and geomorphologic setting, this value can be converted into the Late Pleistocene uplift rate of the Southeastern flank of the Mérida Andes. Our results show that the process of terraces formation in the lower reaches of the Santo Domingo river occurred at a higher frequency (103-104 years) than a glacial/interglacial cycle (104-105 years). According to the global and local climate curve, these terraces were abandoned during warm to cold transitions.

Guzmán, Oswaldo; Vassallo, Riccardo; Audemard, Franck; Mugnier, Jean-Louis; Oropeza, Javier; Yepez, Santiago; Carcaillet, Julien; Alvarado, Miguel; Carrillo, Eduardo

2013-12-01

418

Long term in-situ observations of biomass burning aerosol at a high altitude station in Venezuela - sources, impacts and inter annual variability  

NASA Astrophysics Data System (ADS)

First long-term observations of South American biomass burning aerosol within the tropical lower free troposphere are presented. The observations were conducted between 2007 and 2009 at a high altitude station (4765 m a.s.l.) on the Pico Espejo, Venezuela. Sub-micron aerosol volume, number concentrations of primary particles and particle absorption were observed. Orographic lifting and shallow convection leads to a distinct diurnal cycle at the station. It enables measurements within the lower free troposphere during night time and observations of boundary layer air masses during day time and at their transitional regions. The seasonal cycle is defined by a wet rainy season and a dry biomass burning season. The particle load of biomass burning aerosol is dominated by fires in the Venezuelan savannah. Increases of aerosol concentrations could not be linked to long-range transport of biomass burning plumes from the Amazon basin or Africa due to effective wet scavenging of particles. Highest particle concentrations were observed within boundary layer air masses during the dry season. Ambient sub-micron aerosol volume reached 1.4 ± 1.3 ?m3 cm-3, heated (300 °C) particle number concentrations 510 ± 420 cm-3 and the absorption coefficient 0.91 ± 1.2 Mm-1. The respective concentrations were lowest within the lower free troposphere during the wet season and averaged at 0.19 ± 0.25 ?m3 cm-3, 150 ± 94 cm-3 and 0.15 ± 0.26 Mm-1. A decrease of particle concentrations during the dry seasons from 2007-2009 could be connected to a decrease in fire activity in the wider region of Venezuela using MODIS satellite observations. The variability of biomass burning is most likely linked to the El Niño-Southern Oscillation (ENSO). Low biomass burning activity in the Venezuelan savannah was observed to follow La Niña conditions, high biomass burning activity followed El Niño conditions.

Hamburger, T.; Matis?ns, M.; Tunved, P.; Ström, J.; Calderon, S.; Hoffmann, P.; Hochschild, G.; Gross, J.; Schmeissner, T.; Krejci, R.

2013-05-01

419

Long-term in situ observations of biomass burning aerosol at a high altitude station in Venezuela - sources, impacts and interannual variability  

NASA Astrophysics Data System (ADS)

First long-term observations of South American biomass burning aerosol within the tropical lower free troposphere are presented. The observations were conducted between 2007 and 2009 at a high altitude station (4765 m a.s.l.) on the Pico Espejo, Venezuela. Sub-micron particle volume, number concentrations of primary particles and particle absorption were observed. Orographic lifting and shallow convection leads to a distinct diurnal cycle at the station. It enables measurements within the lower free troposphere during night-time and observations of boundary layer air masses during daytime and at their transitional regions. The seasonal cycle is defined by a wet rainy season and a dry biomass burning season. The particle load of biomass burning aerosol is dominated by fires in the Venezuelan savannah. Increases of aerosol concentrations could not be linked to long-range transport of biomass burning plumes from the Amazon basin or Africa due to effective wet scavenging of particles. Highest particle concentrations were observed within boundary layer air masses during the dry season. Ambient sub-micron particle volume reached 1.4±1.3 ?m3 cm-3, refractory particle number concentrations (at 300 °C) 510±420 cm-3 and the absorption coefficient 0.91±1.2 Mm-1. The respective concentrations were lowest within the lower free troposphere during the wet season and averaged at 0.19±0.25 ?m3 cm-3, 150±94 cm-3 and 0.15±0.26 Mm-1. A decrease of particle concentrations during the dry seasons from 2007-2009 could be connected to a decrease in fire activity in the wider region of Venezuela using MODIS satellite observations. The variability of biomass burning is most likely linked to the El Niño-Southern Oscillation (ENSO). Low biomass burning activity in the Venezuelan savannah was observed to follow La Niña conditions, high biomass burning activity followed El Niño conditions.

Hamburger, T.; Matis?ns, M.; Tunved, P.; Ström, J.; Calderon, S.; Hoffmann, P.; Hochschild, G.; Gross, J.; Schmeissner, T.; Wiedensohler, A.; Krejci, R.

2013-10-01

420

Genes Required for Aerial Growth, Cell Division, and Chromosome Segregation Are Targets of WhiA before Sporulation in Streptomyces venezuelae  

PubMed Central

ABSTRACT WhiA is a highly unusual transcriptional regulator related to a family of eukaryotic homing endonucleases. WhiA is required for sporulation in the filamentous bacterium Streptomyces, but WhiA homologues of unknown function are also found throughout the Gram-positive bacteria. To better understand the role of WhiA in Streptomyces development and its function as a transcription factor, we identified the WhiA regulon through a combination of chromatin immunoprecipitation-sequencing (ChIP-seq) and microarray transcriptional profiling, exploiting a new model organism for the genus, Streptomyces venezuelae, which sporulates in liquid culture. The regulon encompasses ~240 transcription units, and WhiA appears to function almost equally as an activator and as a repressor. Bioinformatic analysis of the upstream regions of the complete regulon, combined with DNase I footprinting, identified a short but highly conserved asymmetric sequence, GACAC, associated with the majority of WhiA targets. Construction of a null mutant showed that whiA is required for the initiation of sporulation septation and chromosome segregation in S. venezuelae, and several genes encoding key proteins of the Streptomyces cell division machinery, such as ftsZ, ftsW, and ftsK, were found to be directly activated by WhiA during development. Several other genes encoding proteins with important roles in development were also identified as WhiA targets, including the sporulation-specific sigma factor ?WhiG and the diguanylate cyclase CdgB. Cell division is tightly coordinated with the orderly arrest of apical growth in the sporogenic cell, and filP, encoding a key component of the polarisome that directs apical growth, is a direct target for WhiA-mediated repression during sporulation. PMID:24065632

Bush, Matthew J.; Bibb, Maureen J.; Chandra, Govind; Findlay, Kim C.; Buttner, Mark J.

2013-01-01

421

[Prevalence of beta-lactamase CTX-M-15 in phylogenetic groups of uropathogenic Escherichia coli isolated from patients in the community of Merida, Venezuela].  

PubMed

In this study we determined the prevalence of extended-spectrum beta-lactamases (ESBLs) in phylogenetic groups of uropathogenic E. coli (UPEC) isolated from patients in the community. Twenty one UPEC strains with reduced susceptibility to broad-spectrum cephalosporins were collected between January 2009 and July 2010, from patients with urinary tract infection who attended the Public Health Laboratory in Mérida, Venezuela. Genotypic characterization determined that all UPEC strains harbored blaBLEEs genes: 76.2% of the strains showed the presence of a single ESBL-producer gene, represented by blaCTX-M-15, whereas 23.8% of UPEC showed various combinations of bla genes (blacCTX-M-15 + blaTEM-1, blaCTX-M-15 + blaSHV and blaSHV + blaTEM-1). In this study, 61.9% of the isolates were placed in phylogroup A and the remaining strains were assigned to group B2 (38.1%). There was no evidence of spread of a particular UPEC clone; only seven strains belonged to a clonal group with an index of similarity greater than 85%. To our knowledge, this is the first description of blxCTX-M-15 in UPEC from patients with community-acquired urinary tract infections, which shows that Venezuela is also part of the so-called CTX-M-15 pandemic. The findings in this study, as well as its clinical and epidemiological implications, lead to the need for monitoring and controlling the spread of CTX-M-15 producing UPECs, not only regionally, but also nationwide. PMID:24758100

Hernández, Erick; Araque, María; Millán, Ysheth; Millán, Beatriz; Vielma, Silvana

2014-03-01

422

Sobre la importancia de la alfabetizacin informtica  

E-print Network

of training high school teachers. The central discussion is developed around the concept of information are discussed some ideas about the integration of information technology in education departing from technology literacy from which are given some analysis elements as well as some particular problems

Spagnolo, Filippo

423

EFECTO PERJUDICIAL DE Moringa oleifera (Lam.) COMBINADA CON OTROS DESECHOS AGRÍCOLAS COMO SUSTRATOS PARA LA LOMBRIZ ROJA (Eisenia spp.)  

Microsoft Academic Search

SUMMARY An experiment was carried out to study the behavior of the red worm (Eisenia spp.) fed with 5 nutritious substrates based in Moringa oleifera (Lam.) foliage, for the nutritional potentiali- ties, and other agricultural wastes in Trujillo state, Venezuela. A randomized design with repeated measurements and three repli- cates was used. Initially, 1.16kg of biomass in 0.5m3 of substrate

Luis José Cov; Danny Eugenio García; Alexander Rafael Castro; María Gabriela Medina

2007-01-01

424

Exhaustive mapping of Co-Mo catalytic activity against their compositions in  

E-print Network

. Furthermore, at high pressure and longer time, the third region with a larger catalytic activity appearedExhaustive mapping of Co-Mo catalytic activity against their compositions in growing SWNTs from catalytic CVD with Co-Mo catalyst was systematically investigated and the catalytic activity was mapped

Maruyama, Shigeo

425

LA CULTURA COMO INVERSIÓN TURÍSTICA. UNA REFLEXIÓN A PROPÓSITO DEL GUGGENHEIM BILBAO  

Microsoft Academic Search

El turismo, objeto de diversas disciplinas, es uno de los sectores más relevantes de la economía mundial, siendo en España la primera industria nacional. En los último años el turismo cultural se ha revelado como un motor esencial de desarrollo para bastantes territorios. Un caso sobresaliente es el conocido como «efecto Guggenheim» que desde su creación en 1997 se ha

Ainhoa Aguirregoitia Martínez

2011-01-01

426

Postcolonialismo como teoría de la administración internacional y su impacto en los negocios internacionales  

Microsoft Academic Search

Este trabajo tiene como objetivo analizar normativamente los discursos del colonialismo y el postcolonialismo como campos de investigación de la administración internacional. Los acercamientos teóricos postcoloniales critican las representaciones euro céntrico y occidental del mundo no-occidental y llaman la atención al conocimiento que claman tener del no occidente. Los acercamientos postcoloniales a la administración internacional también tratan de los supuestos

José G. Vargas-Hernández

2009-01-01

427

[Lipid and fatty acid profile of Perna viridis, green mussel (Mollusca: Bivalvia) in different areas of the Eastern Venezuela and the West Coast of Trinidad].  

PubMed

The species Perna viridis is a highly consumed species, which fast growth makes it an interesting aquaculture alternative for Venezuelan and Trinidad coasts. With the aim to contribute with its nutritional value information, this study analyzed lipid and fatty acid contents from samples taken in five locations from Eastern Venezuela and three from Trinidad West Coast. Total lipids were extracted and quantified, from a pooled sample of 100 organisms per location, by standard gravimetric methods, and their identification and quantification was done by TLC/FID (Iatroscan system). Furthermore, the esterified fatty acids of total lipid, phospholipids and triacylglycerols were identified and quantified by gas chromatography. Eastern Venezuela samples from Los Cedros, La Brea and Chaguaramas showed the highest total lipid values of 7.92, 7.74 and 7.53, respectively, and the minimum values were obtained for La Restinga (6.08%). Among lipid composition, Chacopata samples showed the lowest phospholipid concentration (48.86%) and the maximum values for cholesterol (38.87%) and triacylglycerols (12.26%); besides, La Esmeralda and Rio Caribe samples exhibited maximum phospholipids (88.71 and 84.93 respectively) and minimum cholesterol (6.50 and 4.42%) concentrations. Saturated fatty acids represented between 15.04% and 65.55% within total lipid extracts, with maximum and minimum values for La Esmeralda and Chacopata, respectively. Polyunsaturated results resulted between 7.80 and 37.18%, with higher values in La Brea and lower values in La Esmeralda. For phospholipids, saturated fatty acids concentrations varied between 38.81 and 48.68% for Chaguaramas and Chacopata samples, respectively. In the case of polyunsaturated fatty acids, these varied between non detected and 34.51%, with high concentrations in Los Cedros (27.97%) and Chaguaramas (34.51%) samples. For the triacylglycerols, the saturated fatty acids composition oscillated between 14.27 and 53.80% with low concentrations for Chacopata and high concentration for La Restinga; the polyunsaturated fatty acids were between 4.66 and 35.55% with lower values for Chacopata and higher values for Chaguaramas samples. P. viridis is recommended for human being consumption, according to the high content of unsaturated fatty acids found for this species. PMID:21516644

Koftayan, Tamar; Milano, Jahiro; D'Armas, Haydelba; Salazar, Gabriel

2011-03-01

428

Sedimentary evolution of the upper Cretaceous and late Oligocene sequences, and its relation to oil production, North Monagas area, Eastern Venezuela  

SciTech Connect

The most important oil reservoirs of the Eastern Venezuela Basin are located in the North Monagas Area. These reservoirs are contained within a 3500 ft Cretaceous to Late Oligocene sedimentary section. Daily production is rated at about 350 MBO and 1000 MMCFG. At this moment, these reservoirs are undergoing special studies, in order to establish enhanced recovery projects, for which heterogeneity definition is very important. The database consisted of log analyses of 136 wells, sedimentological and biostratigraphic interpretation of 10,200 ft of cores, and biostratigraphic interpretation of ditch samples from 13 wells. Sedimentary models, based on facies analyses and deltaic conceptual models of 31 separate genetic units were defined. The models allowed for the interpretation of paleoenvironments, sedimentary facies architecture, direction of sedimentation and depocenters. The preferred sediment orientation was determined to be West-East. In the Santa Barbara and Pirital reservoirs the Late Oligocene sediments are composed of fluvial deposits, and the Cretaceous sediments of estuarine deposits. In the Carito-Mulata reservoirs, the Late Oligocene sediments are composed of fluvial to marine deposits, and the Upper Cretaceous sediments of estuarine deposits. Possible preferred transmissibility pathways for fluid injection were described, providing a great support for the enhanced recovery phases of these reservoirs.

Sambrano, J.; Rojas, B.; Rendon, J.; Chigne, R. [Corpoven, S.A., La Cruz (Venezuela); Maguregui, J. [Intevep, Los Teques (Venezuela)

1996-08-01

429

[Cooper, cadmium and lead in the fish Cyprinodon dearborni, in the sediments and in the water of two lagoons in Venezuela].  

PubMed

The concentration of copper, cadmium and lead in superficial sediment, water and the fish Cyprinodon dearborni was determined in two coastal lagoons of Sucre State, Venezuela. Chacopata lagoon is hyper saline while Los Patos lagoon is hypo saline and receives significant wastewater from Cumaná city. Water, sediment and fish samples were collected in February 1998. In the laboratory, samples underwent acid digestion and were analyzed by atomic absorption spectophotometry. The mean values of the metals in C. dearborni from the Chacopata lagoon were: 159.26 +/- 210.68 microg/g for Cu, 44.71 +/- 45.58 microg/g for Cd, and 9.31 +/- 23.34 microg/g for Pb, while for Los Patos lagoon the mean values were: 64.88 +/- 16.30, 19.48 +/- 5.81 and 22.85 +/- 20.00, respectively. In the water column, the metal concentration ranges were: 2.3-11.6, 3.9-5.4 and 21-32 mg/l for copper, cadmium and lead, respectively. These results suggest that metal levels in sediment, water column and organisms in both lagoons do not differ, except for lead, even though only Los Patos receives waste water. PMID:15266812

Toledo, J; Lemus, M; Chung, K S

2000-12-01

430

[Clinical and epidemiological features of leptospirosis in Bolívar state, Venezuela. Comparison of diagnostic methods: LEPTO-Dipstick and plaque macroscopic agglutination test].  

PubMed

Leptospirosis is caused by numerous serovars of Leptospira interrogans. The infection is acquired through the contact of softened skin, mucous and conjunctive with the urine of animals and humans infected by animal carriers. The aim of this study was to determine the clinical and epidemiological features of leptospirosis in Bolívar state Venezuela and to compare the sensibility and specificity of the LEPTO-Dipstick, with the test of macroscopic agglutination in plate with the termorresistent antigen (TR). Thirty one sample of serums were processed of patients with leptospirosis clinic, admitted in the Hospital Universitario "Ruiz y Páez" of Ciudad Bolívar during 12 months. Detection IgM antibodies of anti-Leptospiras was carried out by means of LEPTO-Dipstick and antigen TR. The Microscopic Agglutination Test (MAT) was also, carried out. The general prevalence of leptospirosis in patients who attended the "Ruiz y Paez" Hospital was of 80.6% (n = 25) by means of the determination of the termorresistent antigen. The most frequent serovars identified in Bolívar State, were the serovars: icterohaemorrhagiae, copenhageni (21.3%), autummalis and australis (12.8%). TR antigen and LEPTO Dipstick had a sensibility of 80% and a specificity of 25%. The agreement between both methods was null (Kappa: -0.2). Bolívar state has a high leptospirosis prevalence and the infection should be discarded in those patients with long-term fever and risk factors for the illness. PMID:16353539

Cermeño-Vivas, Julman R; Sandoval-De Mora, Marisol; Bognanno, José F; Caraballo, Alejandro

2005-12-01

431

[Detection of Entamoeba histolytica and Entamoeba dispar by PCR in children, less than five years of age with diarrhea, in Maracaibo, Venezuela. A preliminary study].  

PubMed

To determine the prevalence of Entamoeba histolytica as a producer of diarrhea, a study was conducted in children, less than five years of age, with diarrhea who attended several out patient clinics of the Servicio Aut6nomo Hospital Universitario, Maracaibo, Venezuela. A macroscopic and microscopic examination with physiological saline, lugol and Kinyoun staining were performed to the stool samples obtained. The remainder of the sample was frozen until DNA extraction, and PCR amplification was performed separately for E. histolytica and E. dispar. Microscopic examination showed no trophozoites and/or cysts of Entamoeba histolytica/dispar/moshkovskii, or intestinal coccidians in any of the 50 samples analyzed. Parasites detected were Giardia lamblia (6%), Blastocystis sp. (4%), Pentatrichomonas hominis (2%), Ascaris lumbricoides (2%) and Trichuris trichiura (2%). By PCR, six samples (12%) had DNA of E. dispar and two (4%) had DNA from E. histolytica; no child showed association of both amoebae. The two children who had E. histolytica were one-year-old. E. dispar was detected in younger children. We suggest that the prevalence of E. histolytica in children under five years is really low. PMID:24502179

Bracho Mora, Angela; Rivero de Rodríguez, Zulbey; Arraiz, Nailet; Villalobos, Rafael; Urdaneta, Haydee

2013-12-01

432

Effects of Land Use Change and Seasonality of Precipitation on Soil Nitrogen in a Dry Tropical Forest Area in the Western Llanos of Venezuela  

PubMed Central

We evaluated changes of different soil nitrogen forms (total N, available ammonium and nitrate, total N in microbial biomass, and soil N mineralization) after conversion of semideciduous dry tropical forest in 5- and 18-year-old pastures (YP and OP, resp.) in the western Llanos of Venezuela. This evaluation was made at early rainy season, at end rainy season, and during dry season. With few exceptions, no significant differences were detected in the total N in the three study sites. Compared to forest soils, YP showed ammonium losses from 4.2 to 62.9% and nitrate losses from 20.0 to 77.8%, depending on the season of the year. In OP, the ammonium content increased from 50.0 to 69.0% at the end of the rainy season and decreased during the dry season between 25.0 and 55.5%, whereas the nitrate content increased significantly at early rainy season. The net mineralization and the potentially mineralizable N were significantly higher (P < 0.05) in OP than in forest and YP, which would indicate a better quality of the substrate in OP for mineralization. The mineralization rate constant was higher in YP than in forest and OP. This could be associated with a reduced capacity of these soils to preserve the available nitrogen. PMID:25610907

González-Pedraza, Ana Francisca; Dezzeo, Nelda

2014-01-01

433

Analysis of number size distributions of tropical free tropospheric aerosol particles observed at Pico Espejo (4765 m a.s.l.), Venezuela  

NASA Astrophysics Data System (ADS)

The first long-term measurements of aerosol number and size distributions in South-American tropical free troposphere (FT) were performed from March 2007 until March 2009. The measurements took place at the high altitude Atmospheric Research Station Alexander von Humboldt. The station is located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Aerosol size distribution and number concentration data was obtained with a custom-built Differential Mobility Particle Sizer (DMPS) system and a Condensational Particle Counter (CPC). The analysis of the annual and diurnal variability of the tropical FT aerosol focused mainly on possible links to the atmospheric general circulation in the tropics. Considerable annual and diurnal cycles of the particle number concentration were observed. Highest total particle number concentrations were measured during the dry season (January-March, 519 ± 613 cm-3), lowest during the wet season (July-September, 318 ± 194 cm-3). The more humid FT (relative humidity (RH) range 50-95 %) contained generally higher aerosol particle number concentrations (573 ± 768 cm-3 during dry season, 320 ± 195 cm-3 during wet season) than the dry FT (RH < 50 %, 454 ± 332 cm-3 during dry season, 275 ± 172 cm-3 during wet season), indicating the importance of convection for aerosol distributions in the tropical FT. The diurnal cycle in the variability of the particle number concentration was mainly driven by local orography.

Schmeissner, T.; Krejci, R.; Ström, J.; Birmili, W.; Wiedensohler, A.; Hochschild, G.; Gross, J.; Hoffmann, P.; Calderon, S.

2011-04-01

434

Deep-seated gravitational slope deformations along the active Boconó Fault in the central portion of the Mérida Andes, western Venezuela  

NASA Astrophysics Data System (ADS)

Two very large deep-seated gravitational slope deformations in the highlands of the Mérida Andes, Venezuela, are herein described: the Mucubají Pass and Cerro La Camacha. These slope movements have slid in post-Last Glacial Maximum times. In addition, both landslides are in very close association with the active Boconó Fault trace. The Cerro La Camacha (Camacha Range) landslide is fault bounded along its northwest flank, whereas the Mucubají pass mass movement is even cut by the active fault trace. The almost 10 km long Mucubají slide mobilizes LGM moraine deposits along the unconformable basement contact. La Camacha slope movement is a sackung-type landslide, involving two huge masses that affect the entire northwestern slope of the La Camacha Range. This sackung is at least 20 km long, paralleling the active Boconó Fault trace. Combination of high relief energy (gravitational forces) and seismic shaking related to an on-site active fault could be responsible for the destabilization of the slopes or massif in both cases. Although the seismically-induced (re-)activation of the La Camacha landslide is very likely, there is no proof for that yet. Conversely, the Mucubají slide shows geomorphic, geodetic and sedimentary evidence of episodic activity in recent times, which could be ascribed to seismic triggering. In the particular case of the La Camacha sackung, the combination of dextral slip along the Boconó Fault and a SE-dipping fault plane could additionally favor the destabilization of the NW slope of the La Camacha Range.

Audemard, Franck A.; Beck, Christian; Carrillo, Eduardo

2010-12-01

435

Seismic detection of fault zone hydrocarbon conduit-seal potential using velocity, frequency, and Q analysis: La Concepcion Field, Lake Maracaibo Venezuela example  

NASA Astrophysics Data System (ADS)

The 3-D Post-Stack Time Migrated Seismic Data of La Concepcion Field, Maracaibo Basin, Venezuela cover an existing field with known oil and gas pay zones. The thesis problem is how to use this seismic data in an interpretation of leaky faults that occur in the exploration area of interest. A solution to the problem was obtained using an integrated geophysical approach that included published seismic attribute methods (Variance Cube, Geoframe IESX). Specific developments in this thesis to solve the interpretation problem of leaky faults in the region include (1) an image ray perturbation approach for updating the interval velocity in a faulted domain (2) a peak frequency approach to attenuation estimation within intervals and (3) a scaled interpretation of the velocity measurements at sonic, checkshot and surface seismic reflection data. The first development refines the interval velocities within fracture zones. The second development identifies anomalous attenuation most likely due to the presence of gas. The combined effects of low interval velocity and high attenuation are interpreted to be signs of leaking faults.

Alahdal, Ahmed Omar

436

Characterization of the mineral phosphate-solubilizing activity of Pantoea agglomerans MMB051 isolated from an iron-rich soil in southeastern Venezuela (Bolívar State).  

PubMed

The mineral phosphate-solubilizing (MPS) activity of a Pantoea agglomerans strain, namely MMB051, isolated from an iron-rich, acidic soil near Ciudad Piar (Bolívar State, Venezuela), was characterized on a chemically defined medium (NBRIP). Various insoluble inorganic phosphates, including tri-calcium phosphate [Ca(3)(PO(4))(2)], iron phosphate (FePO(4)), aluminum phosphate (AlPO(4)), and Rock Phosphate (RP) were tested as sole sources of P for bacterial growth. Solubilization of Ca(3)(PO(4))(2) was very efficient and depended on acidification of the external milieu when MMB051 cells were grown in the presence of glucose. This was also the case when RP was used as the sole P source. On the other hand, the solubilization efficiency toward more insoluble mineral phosphates (FePO(4) and AlPO(4)) was shown to be very low. Even though gluconic acid (GA) was detected on culture supernatants of strain MMB051, a consequence of the direct oxidation pathway of glucose, inorganic-P solubilization seemed also to be related to other processes dependent on active cell growth. Among these, proton release by ammonium (NH(4)(+) ) fixation appeared to be of paramount importance to explain inorganic-P solubilization mediated by strain MMB051. On the contrary, the presence of nitrate (NO(3)(-) ) salts as the sole N source affected negatively the ability of MMB051 cells to solubilize inorganic P. PMID:19067045

Sulbarán, Miguel; Pérez, Elizabeth; Ball, María M; Bahsas, Alí; Yarzábal, Luis Andrés

2009-04-01

437

Overview of radiometric ages in three allochthonous belts of Northern Venezuela: Old ones, new ones, and their impact on regional geology  

USGS Publications Warehouse

The margin of northern Venezuela is a complex zone representing the orogenic events from basement formation to subsequent subduction and exhumation during transpressional collision. This boundary zone has six east-west-trending belts that each record a different segment of its development. This geologic complexity requires radiometric ages to unravel, and we herein provide 48 new ages including U-Pb (4), Rb-Sr (2), 40Ar/39Ar (24), zircon and apatite fission-track (17), and 14C (1) ages to constrain the evolution of three of these belts. These three belts are the Cordillera de la Costa, Caucagua-El Tinaco, and Serran??a del Interior belts. In the Cordillera de la Costa belt, U-Pb geochronologic data indicate portions of the basement igneous and metaigneous rocks formed in the Cambro-Ordovician (513-471 Ma). New 40Ar/39Ar data from Margarita Island indicate that some of the subduction complex was rapidly cooled and exhumed, whereas other portions indicate slower cooling. This contrasts with new 40Ar/39Ar data from the Puerto Cabello. ?? 2005 Geological Society of America.

Sisson, V.B.; Ave Lallemant, H.G.; Ostos, M.; Blythe, A.E.; Snee, L.W.; Copeland, P.; Wright, J.E.; Donelick, R.A.; Guth, L.R.

2005-01-01

438

78 FR 36163 - Bitterroot National Forest, Darby Ranger District, Como Forest Health Project  

Federal Register 2010, 2011, 2012, 2013, 2014

...populations; (2) reduce fuel loads and maintain the historic fire return interval; (3) improve forest resilience to dwarf mistletoe, root rot, Douglas-fir beetle, and spruce budworm; (4) and maintain the visual integrity of the larger Lake Como...

2013-06-17

439

Castração química como pena, tratamento médico ou experimento científico : considerações bioéticas.  

E-print Network

??Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ciências da Saúde, Programa de Pós-Graduação em Bioética, 2014. A pedofilia é classificada como doença psiquiátrica e sua prática… (more)

Maia, Thais Meirelles de Sousa

2014-01-01

440

On Resilience of Multicommodity Dynamical Flow Networks Gustav Nilsson, Giacomo Como, and Enrico Lovisari  

E-print Network

On Resilience of Multicommodity Dynamical Flow Networks Gustav Nilsson, Giacomo Como, and Enrico of the network. Index Terms-- Dynamical flow networks, multicommodity flows, resilience, distributed routing, heterogeneous routing. I. INTRODUCTION In a multicommodity network particles of different classes flow through

Como, Giacomo

441

Atomic-Scale Structure of Co–Mo–S Nanoclusters in Hydrotreating Catalysts  

Microsoft Academic Search

By means of scanning tunneling microscopy (STM), it has been possible to obtain the first atomic-scale images of the Co–Mo–S structure present in hydrodesulfurization (HDS) catalysts. Information on the catalytically important edge structures has been obtained by synthesizing single-layer Co–Mo–S nanoclusters using the Au(111) herringbone structure as a template. It is observed that the presence of the Co promoter atoms

J. V Lauritsen; S Helveg; E Lægsgaard; I Stensgaard; B. S Clausen; H Topsøe; F Besenbacher

2001-01-01

442

Planktonic foraminiferal shell weight and boron isotopic composition as proxies for carbonate system parameters: Insight from sediment trap studies in the Cariaco Basin, Venezuela  

NASA Astrophysics Data System (ADS)

The area-normalized shell weight (ANSW) and boron isotopic compositions of planktonic foraminifera collected from Cariaco Basin, Venezuela sediment traps were used as proxies for seawater carbonate ion concentrations ([CO32-]) and pH respectively. Three species of planktonic forams: G. ruber (pink), G. sacculifer, and O. universa were used in conjunction with known hydrographic data to calibrate the relationship between carbonate ion concentration and area-normalized shell weight. Individuals of each species were picked from sediment trap samples collected between January 2005 and September 2008, then weighed and photographed for size analysis. The individual foraminiferal ANSW were averaged for each sample (n > 10) and compared to the concurrent [CO32-] calculated from time-equivalent hydrographic data (pH, alkalinity, temperature, salinity, nutrient concentrations). The results of this study revealed strong positive-linear relationships between [CO32-] and the ANSW of G. ruber (r2 = 0.84), G. sacculifer (r2 = 0.90), and O. universa (r2 = 0.52) for broad size fractions. The results also suggest that the relationship between [CO32-] and ANSW is variable amongst species and thus species-specific equations are necessary when using foraminiferal ANSW during down-core paleo-oceanographic reconstructions. The relationship between pH and the boron isotopic composition of sediment trap foraminiferal calcite was also assessed. Trap samples containing 3-5 mg of O. universa were prepared for boron isotopic analysis on the Neptune MC-ICP-MS using a micro-sublimation method following oxidative cleaning and dissolution via nitric acid. The results of these sediment trap calibration studies were then compared to previously published calibration equations. The determination of seawater [CO32-] and pH using the proxies above will allow for the derivation of all other carbonate parameters during down-core paleo-climatic and paleo-oceanographic studies.

Marshall, B. J.; Thunell, R.; Henehan, M. J.; McConnell, M. C.; Astor, Y.

2012-12-01

443

Light and desiccation responses of some Hymenophyllaceae (filmy ferns) from Trinidad, Venezuela and New Zealand: poikilohydry in a light-limited but low evaporation ecological niche  

PubMed Central

Background and Aims Hymenophyllaceae (filmy ferns) are typically plants of shady, constantly moist habitats. They attain greatest species diversity and biomass in humid tropical montane forests and temperate hyperoceanic climates. This paper presents ecophysiological data bearing on their worldwide ecological niche space and its limits. Methods Chlorophyll fluorescence was used to monitor recovery in desiccation experiments, and for measurements of 95 % saturating irradiance [photosynthetic photon flux density (PPFD95 %)] of photosynthetic electron flow and other parameters, in the New Zealand Hymenophyllum sanguinolentum, and three species each of Hymenophyllum and Trichomanes from forests in Trinidad and Venezuela. Key Results Hymenophyllum sanguinolentum was comparable in desiccation tolerance and light responses with the European species. The more common species in the two tropical forests showed PPFD95 % >100 µmol m?2 s?1, and withstood moderate desiccation (–40 MPa) for several days. The four most shade-adapted species had PPFD95 % ?51 µmol m?2 s?1, and were sensitive to even mild and brief desiccation (–22 MPa for 3 d). Conclusions Light and desiccation responses of filmy ferns can be seen as an integrated package. At low light and windspeed in humid forests, net radiation and saturation deficit are low, and diffusion resistance high. Water loss is slow and can be supported by modest conduction from the sub-stratum. With higher irradiance, selection pressure for desiccation tolerance increases progressively. With low light and high humidity, the filmy fern pattern of adaptation is probably optimal, and the vascular plant leaf with mesophyll and stomata offers no advantage in light capture, water economy or CO2 uptake. Trade-offs between light adaptation and desiccation tolerance, and between stem conduction and water absorption through the leaf surface, underlie adaptive radiation and niche differentiation of species within the family. Hymenophyllaceae are a rare example of an evolutionary shift of adaptive strategy from typical vascular plant adaptation to the poikilohydry most typical of bryophytes. PMID:22334496

Proctor, Michael C. F.

2012-01-01

444

Export of dissolved organic and inorganic nitrogen and total suspended sediments across an urbanization gradient in four tropical rivers of Venezuela  

NASA Astrophysics Data System (ADS)

We determined monthly concentrations of total dissolved nitrogen (TDN), dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON) and total suspended sediment (TSS) from 4 Venezuelan watersheds from August 2008 to September 2009. Three of these watersheds are mountainous rivers (Tuy, Neverí and Manzanares) and one is flat (Unare River). The three mountainous rivers vary in the degree of urbanization, with the Tuy hosting Caracas, the largest city in Venezuela. We found an order of magnitude larger TDN concentrations in the Tuy, which is impacted mainly by untreated point sources derived from Caracas metropolitan area. The largest TSS values were observed in the three mountainous rivers (Tuy, Neveri and Manzanares). TDN and TSS concentrations varied seasonally with larger TDN and lower TSS values during the dry season for all rivers. Most of the annual discharge of TDN (92%) and TSS (97%) takes place during the rainy season. Our results suggest that urbanization is the largest contributor affecting the composition and magnitude of TDN, whereas orography and local hydrology control the discharge of both TSS and TDN. We calculated the Water Pollution Level (WPL) for DIN and DON to determine the degree of contamination of these species in the evaluated watersheds. WPL values less than 1 indicate that there is in average enough dilution capacity in the river to assimilate the pollutant, whereas WPL larger than 1 indicate that the pollution assimilation capacity has been surpassed. All our evaluated rivers but the Tuy River show WPL-DIN and WPL-DON values between 0.1 and 0.96. The Tuy River had a WPL-DIN=6.3 and WPL-DON= 7.5. We attribute the Tuy River's large DIN and DON contamination to untreated urban point sources due to the strong correlation between population density and DIN and DON concentration from the evaluated watersheds. Our results suggest that urgent water treatment is required for this watershed to diminish the impact in coastal ecosystems.

Rasse, R. J.; Perez, T.; Giuliante, A.; Donoso, L.

2012-12-01

445

Detection of dengue viruses in field-caught Aedes aegypti (Diptera: Culicidae) in Maracay, Aragua state, Venezuela by type-specific polymerase chain reaction.  

PubMed

Virological surveillance of dengue viruses in Aedes aegypti populations constitutes a powerful tool for early prediction of dengue outbreaks. We have standardized a protocol for viral RNA extraction from individual and pools of mosquitoes that permits a sensitive detection of dengue virus without RNA degradation or PCR inhibition when we apply a semi-nested RT-PCR. The limit of detection for each dengue serotype was 0.1 PFU. In a prospective field study conducted from November 2000 to December 2001, adult female A. aegypti mosquitoes from several municipalities with high dengue transmission in Maracay, Aragua State, Venezuela were collected and screened for dengue viruses using RT-PCR. We analyzed a total of 296 A. aegypti pools (1,632 mosquitoes); of these, 154 pools (469 mosquitoes) were collected from houses with persons with clinical diagnosis of dengue (dengue houses), and 142 pools (1,163 mosquitoes) from adjacent residences (neighbour houses). From the dengue houses, eight mosquito pools (5.2%) were positive for DENV-1 (0.7%), DENV-3 (3.2%) and DENV-4 (1.3%) viruses. From the neighbour houses, 18 mosquito pools (12.7%) were positive for DENV-3 (12%) and DENV-4 (0.7%) viruses. From these 26 RT-PCR positive mosquito pools (containing 1-25 mosquitoes each), 22 pools (84.6%) were positive for DENV-3. The most prevalent serotype in the 2001 dengue outbreak was also DENV-3. The minimum infection rate in both A. aegypti collections, from dengue houses and neighbour houses was 17 and 15 per 1,000, respectively. The relevance of these results for dengue surveillance is discussed. PMID:15639750

Urdaneta, Ludmel; Herrera, Flor; Pernalete, Martha; Zoghbi, Normig; Rubio-Palis, Yasmín; Barrios, Roybel; Rivero, José; Comach, Guillermo; Jiménez, Matilde; Salcedo, Maria

2005-03-01

446

[Present state of diseases and other signs of reef deterioration at seven coral reefs at Los Roques Archipelago National Park, Venezuela].  

PubMed

This work was aimed to determine the incidence of coral diseases in six different reef sites at the Parque Nacional Archipiélago de Los Roques, Venezuela: Arrecife de herradura, Arrecife costanero, both at Dos Mosquises Sur Key, Boca de Cote, Carenero, Crasquí and Pelona de Rabusquí. Each reef was surveyed by using ten 10 m2-band transects (10 x 1 m), placed parallel to the long axis of the reef within a depth gradient ranging from 1 to 9 m depth. All healthy and injured corals, along each band transect, were counted and identified to species level. Additionally, all diseases and recent mortality that were still identifiable on each colony were also recorded. The occurrence of diseased colonies and other signs of reef decline between localities were compared by means of a Chi2 test. The absolute, relative and mean incidence was estimated for each disease and other signs of damage observed for all coral species surveyed at each site. The overall incidence of coral diseases was low for all the localities surveyed, only 6.04% of the 3 344 colonies observed, showed signs of diseases. The most important diseases recorded were the Yellow-Blotch Disease (YBD) and Dark Spots Disease (DSD) with 2.1% +/- 1.52 y 2.1% +/- 2.54, respectively. Significant differences were found in the incidence of coral diseases between reef sites (Chi2 p < 0.05). Finally, the occurrence of colonies injured by parrotfish bites and pomacentrids was higher compared with the incidence of coral diseases for all the reefs surveyed. In conclusion, currently the proportion of healthy colonies at Los Roques coral reefs is higher than the percentage of both diseased and injured colonies. PMID:15264569

García, Adriana; Cróquer, Aldo; Pauls, Sheila M

2003-06-01

447

Atmospheric deposition of SO 4-S and (NH 4+NO 3)-N at two rural sites in the Western Maracaibo Lake Basin, Venezuela  

NASA Astrophysics Data System (ADS)

Rain samples were collected by events from November 1988 to November 1989 at La Esperanza and Catatumbo sites. Dry deposition was collected only at La Esperanza. Volume weighted average pH values of the rainfall samples were between 4.23 and 4.64, individual samples reaching as low as pH 3.0. An excess of sulfate greater than 96% was obtained at both sites. The wet deposition of hydronium and sulfate showed the same seasonal cycle. The highest inputs were obtained in April during the early rainy season, and November which is the second peak rainfall period. The amounts of (NH 4+NO 3)-N ha -1 yr -1 added by wet deposition ranged from 5.2 kg at La Esperanza to 11.4 kg at Catatumbo (ammonium accounts for about 67% of these amounts), and the corresponding amounts of SO 4-S deposited ranged from 10.5 to 12.5 kg, respectively. These amounts of S and N annually deposited by precipitation are substantially higher than those found in eastern Venezuelan sites, and slightly lower than the values reported for rural areas of Europe and North America. In La Esperanza it was estimated that wet deposition accounts for about 93% of the inorganic-N and for about 80% of the SO 4-S annually added by dry and wet deposition. It is envisaged that in Lake Maracaibo Basin large argricultural and uncultivated land areas downwind of the El Tablazo Petrochemical Complex, Cardon-Amuay and, probably, the Aruba-Curacao refineries and urban Maracaibo might already be affected by anthropogenic air pollution as evidenced by the higher level of H +, SO -24, NO -3 and NH +4 wet deposition found at the La Esperanza and Catatumbo sites in comparison with other rural sites in Venezuela.

Morales, Jose Agustin; Bifano, Claudio; Escalona, Andres

448

Geochemistry of surface and subsurface waters in quartz-sandstones: significance for the geomorphic evolution of tepui table mountains (Gran Sabana, Venezuela)  

NASA Astrophysics Data System (ADS)

In situ measurements of discharge, pH, electric conductivity (EC), temperature, and SiO2 content have been carried out during five expeditions in the last 20 years on the summit plateaus, inside caves and along the rivers of the surrounding lowlands of three tepui massifs in Venezuela (Auyan, Roraima, and Chimanta). Additionally, detailed chemical analyses were performed on waters sampled in a newly discovered extensive quartz-sandstone cave system on the Auyan Tepui. Rock samples of the quartz-sandstone bedrock from different locations have been analysed to obtain their chemical composition with a wavelength dispersive X-ray fluorescence spectrometer. These data show that the majority of silica present in surface and subsurface water comes from dissolution of quartz and only in minor amount from hydrolysis of other silicate minerals. Probably the presence of a hardened crust of iron hydroxides limits the dissolution of silica on the top surface of tepuis. Dissolution in the subsurface, instead, is more significant and causes, in the long term, the “arenisation” of the quartz-sandstone and its subsequent removal by mechanical erosion. On the other hand, waters flowing on the arkosic rock outcropping on the lowland below the tepuis obtain their high dissolved silica content mainly from hydrolysis of silicates. The morphological evolution of these table mountains appears thus to be controlled mainly by the underground weathering of the quartz-sandstone, with the opening of deep fractures (grietas) and the collapse of large underground horizontal cave systems. Scarp retreat, instead, seems to be related to the higher weathering rate of the more arkosic formations underlying the quartz-sandstones.

Mecchia, Marco; Sauro, Francesco; Piccini, Leonardo; De Waele, Jo; Sanna, Laura; Tisato, Nicola; Lira, Jesus; Vergara, Freddy

2014-04-01

449

Children live, feel, and respond to experiences of food insecurity that compromise their development and weight status in peri-urban Venezuela.  

PubMed

Children's experiences of food insecurity (FI) may be conceptually distinct and different from those of adults. Previous study of children's experiences of FI has relied primarily on their parents' perspective. This study explored, described, and conceptualized experiences of FI in children attending 5 public schools in peri-urban areas of the Miranda State, Venezuela, South America using a naturalistic approach. Children aged 10-17 y were studied through focus groups (n = 42) and individual interviews (n = 13). Interviews were recorded, transcribed, and analyzed using grounded theory. Children were cognitively aware of FI, worry in their parents, and causes both external and internal to their households. Children were also emotionally aware of FI, with feelings of concern, anguish, and sadness, and manifestations such as crying. Children reported being physically hungry, experiencing reduced quantity and quality of food intake, having smaller meals, and recognizing thinness and fainting as consequences. Ch