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Sample records for northwestern venezuelan andes

  1. Seismic evidence for blind thrusting of the northwestern flank of the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    de Toni, Bruno; Kellogg, James

    1993-12-01

    Surface geology and seismic and well data from the northwestern flank of the Venezuelan Andes indicate overthrusting of Andean basement rocks toward the adjacent Maracaibo Basin along a blind thrust fault. The frontal monocline is interpreted as the forelimb of a northwestward verging fault-related fold deformed over a crustal-scale ramp. The Andean block has been thrust 20 km to the northwest and uplifted 10 km on a ramp that dips about 20°-30° southeastward. The thrust fault ramps up through crystalline basement rocks to a decollement horizon within the shaly units of the Cretaceous Colon-Mito Juan formations. Backthrusts in the monocline produce a wedge geometry and reduce the amount of blind slip required on the decollement northwest of the Andes. The rigid Andean uplift was caused by northwest-southeast compressive tectonic forces related to the convergence of the Caribbean plate, the Panama volcanic arc, and northwestern South America. The thick (up to 6 km) molasse deposits accumulated in the foredeep basin indicate that the Venezuelan Andes started to rise as early as the early Miocene. However, a late Miocene intramolasse unconformity marks the beginning of the formation of the monocline and the greatest uplift. The crustal-scale fault-related fold model may explain structural features seen in other areas of basement-involved foreland deformation.

  2. Morphostructural Analysis of an Escape Tectonic Zone : the North-Western Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Dhont, D.; Backe, G.; Hervouet, Y.; Niviere, B.

    2004-12-01

    Lateral motions in active collisional areas have been mainly described in the Asian and European belts. The most common view is that part of the intracontinental convergence between to plates is accommodated by major strike-slip faults bounding a lithospheric block that laterally moves away. This process, privileging horizontal compressional forces at boundaries of the moving block corresponds to an extrusion or escape of the continental landmass. Diffuse extensional deformation within the block implies that buoyancy forces, leading eventually to an extensional collapse, must be taken into account. Escape of the block is perpendicular to the convergence direction of the orogen and can only occur if a free lateral boundary exists. Our study concerns the analysis of the deformation in the northwestern part of the Venezuelan Andes, located in the northern part of South America. It is based on analysis of satellite and Digital Elevation Model imagery, complemented by field structural observations. We shall describe new tectonic features advocating that part of the belt is subjected to lateral escape tectonics during the Plio-Quaternary. The zone displays major active faults forming crustal blocks having a triangular shape pattern, and which are moving toward the north-east. The triangular corners are composed of smaller pluri-kilometre size crustal blocks bounded by normal faults. A major result is that in an area characterized by on-going intracontinental convergence, extension and strike-slip deformations predominate. In order to better constrain the depth of the deformation, we have generated a 3-D geologic model displaying the seismicity the area showing that the earthquakes are mainly restricted to the crust. The type and distribution of the deformation are not consitent with the behaviour of a simple rigid extrusion. The Venezuelan Andes are rather composed of crustal blocks that are tilted and move relative to each others. This is consistent with extensional

  3. Evidence from the northwestern Venezuelan Andes for extraterrestrial impact: The black mat enigma

    NASA Astrophysics Data System (ADS)

    Mahaney, W. C.; Kalm, V.; Krinsley, D. H.; Tricart, P.; Schwartz, S.; Dohm, J.; Kim, K. J.; Kapran, B.; Milner, M. W.; Beukens, R.; Boccia, S.; Hancock, R. G. V.; Hart, K. M.; Kelleher, B.

    2010-03-01

    A carbon-rich black layer encrusted on a sandy pebbly bed of outwash in the northern Venezuelan Andes, previously considered the result of an alpine grass fire, is now recognized as a 'black mat' candidate correlative with Clovis Age sites in North America, falling within the range of 'black mat' dated sites (~ 12.9 ka cal BP). As such, the bed at site MUM7B, which dates to < 11.8 ka 14C years BP (raw dates) and appears to be contemporaneous with the Younger Dryas (YD) cooling event, marks a possibly much more extensive occurrence than previously identified. No fossils (megafauna) or tool assemblages were observed at this newly identified candidate site (3800 a.m.s.l.), as in the case of the North American sites. Here, evidence is presented for an extraterrestrial impact event at ~ 12.9 ka. The impact-related Andean bed, located ~ 20 cm above 13.7-13.3 ka cal BP alluvial and glaciolacustrine deposits, falls within the sediment characteristics and age range of 'black mat' dated sites (~ 12.9 ka cal BP) in North America. Site sediment characteristics include: carbon, glassy spherules, magnetic microspherules, carbon mat 'welded' onto coarse granular material, occasional presence of platinum group metals (Rh and Ru), planar deformation features (pdfs) in fine silt-size fragmental grains of quartz, as well as orthoclase, and monazite (with an abundance of Rare Earth Elements—REEs). If the candidate site is 'black mat', correlative with the 'black mat' sites of North America, such an extensive occurrence may support the hypothesized airburst/impact over the Laurentide Glacier, which led to a reversal of Allerød warming and the onset of YD cooling and readvance of glaciers. While this finding does not confirm such, it merits further investigation, which includes the reconnaissance for additional sites in South America. Furthermore, if confirmed, such an extensive occurrence may corroborate an impact origin.

  4. Orogenic float of the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Monod, Bernard; Dhont, Damien; Hervouët, Yves

    2010-07-01

    The Venezuelan (or Mérida) Andes are a NE-trending intracontinental orogen that started to rise from the Middle Miocene due to the E-W far field convergence between the Maracaibo block to the northwest and the Guyana shield to the southeast. Oblique convergence is responsible for strain partitioning with thrusting along both foreland basins and right-lateral strike-slip faulting along the NE-SW Boconó fault cutting the Venezuelan Andes along-strike. The central part of the belt is also cut by the N-S left-lateral strike-slip Valera fault that connects the Boconó fault, both faults bounding the Trujillo block that escapes towards the NNE. Even though the regional geology of belt is well known, its structure at depth remains a matter of debate. Our work, based on the integration of geological and geophysical data aims to better constrain the deep geometry of faults and the tectonic evolution of the mountain belt. We used the orogenic float model to construct two NW-SE trans-Andean crustal scale balanced sections. The Late Neogene-Quaternary shortening varies from 40 km in the south to 30 km in the north across the Trujillo block, indicating that a quarter of the deformation seems to be absorbed by the tectonic escape process. More importantly, a major reorganization in the crust took place in the Early Pliocene. It is characterized by the imbrication of the Maracaibo crust into the Guyana crust. This resulted in the subduction of the Guyana lower crust and the formation of a NW-vergent basement thrust propagating upwards and surfacing along the Las Virtudes thrust. Rapid uplift of the northern flank of the belt subsequently occurred together with massive deposition of the Plio-Quaternary coarse grained Betijoque formation in the northwestern foreland basin.

  5. 3D Geomodeling of the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Monod, B.; Dhont, D.; Hervouet, Y.; Backé, G.; Klarica, S.; Choy, J. E.

    2010-12-01

    The crustal structure of the Venezuelan Andes is investigated thanks to a geomodel. The method integrates surface structural data, remote sensing imagery, crustal scale balanced cross-sections, earthquake locations and focal mechanism solutions to reconstruct fault surfaces at the scale of the mountain belt into a 3D environment. The model proves to be essential for understanding the basic processes of both the orogenic float and the tectonic escape involved in the Plio-Quaternary evolution of the orogen. The reconstruction of the Bocono and Valera faults reveals the 3D shape of the Trujillo block whose geometry can be compared to a boat bow floating over a mid-crustal detachment horizon emerging at the Bocono-Valera triple junction. Motion of the Trujillo block is accompanied by a generalized extension in the upper crust accommodated by normal faults with listric geometries such as for the Motatan, Momboy and Tuñame faults. Extension may be related to the lateral spreading of the upper crust, suggesting that gravity forces play an important role in the escape process.

  6. Tectonics of the northern Venezuelan Andes from satellite images analysis

    NASA Astrophysics Data System (ADS)

    Dhont, D.; Backé, G.; Hervouët, Y.

    2003-04-01

    The northern part of the Venezuelan (or Merida) Andes is a complex area comprising a Cretaceous to Quaternary sedimentary sequence that recorded two main stages of deformation: (1) the uplifting of the Carribean belt in the Cretaceous-Eocene (Carribean stage), which is superimposed by (2) the building of the Venezuelan Andes since the Miocene (Andean stage). The study area is located at the junction between the Merida Andes and the Caribbean belt, and constitutes a key zone to understand the transition between these two orogens. Our aim is to implement the structural mapping in order to propose a new model of deformation at regional scale. The methodology is based on analysis of Landsat TM, SPOT, radarsat and DEM images, and is complemented by geological studies in the field. Integration of this complementary data set into a GIS enables a new understanding of the tectonics of the northern Venezuelan Andes during the Neogene-Quaternary. We focused on three main areas where the structures are clearly exposed. In the Mene Grande area, our structural analysis allows to precise the geometry and timing of deformations. The Cerro la Galera anticline is a fault bend fold propagating to the SW that developped along the Burro Negro fault during the Eocene-Oligocene and then eroded. The Cerro La Luna (or Cerro Misoa) is a pop-up structure that developped later during the Andean stage. In the Jirajara area, we have evidenced a releasing-bend basin at left-stepping offset of the Valera fault. To the east, this basin is surrounded by the relief of the Serrania de Jirajara which gravitationally collapses towards the lowland of the basin. In the Sierra de Barragua area, we mapped the left-lateral strike-slip Rio Diquiva fault 25 km east of the Valera fault. This fault is a major structure bounding two distincts areas of sedimentation during the Eocene. The synthesis of these observations shows that the northern Venezuelan Andes consist in a mosaic of independent crustal blocks

  7. [Description of the seismological network of the Venezuelan Andes].

    PubMed

    Guada, Carlos; Morandi, María; Silva, José

    2003-01-01

    Western Venezuela shows a broad zone characterized by a moderate seismicity level, which has been the scenery of various historic earthquakes of destructive character. The beginning of the seismic instrumentation in the area dates from 1969, nevertheless it was 10 years later when the seismological network of the Venezuelan Andes (REDSAV) was permanently installed in order to characterize the regional earthquake activity. The REDSAV is an array of 10 remote seismic stations that sends the seismic signals by analog telemetry to the central station, located in the city of Mérida, where the digitalization, automatic event detection in real time and the analysis and off-line processing of the seismic information is carried out. During the last 10 years important advances have been taken place in terms of its operativity, which includes a dynamic web site (http://lgula.ciens.ula.ve) with a catalog of western Venezuela earthquakes, where the user can visualize the seismograms, the P and S wave arrival time, the polarities and epicentral maps; moreover, it is possible to select events applying temporal, spatial and magnitute criteria. In this paper the technical characteristic of the equipment are described and the advances registered in the last years referring to the automatic acquisition system, processing of the information and seismologic catalog of the REDSAV, whose systematic use during a decade has permitted to gather the biggest information base of related with the seismicity of the south-western Venezuela.

  8. Application of the Orogenic Float Model for the Structural Evolution of the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Dhont, D.; Monod, B.; Hervouet, Y.; Klarica, S.

    2010-12-01

    The Venezuelan (or Mérida) Andes form a NE-SW-striking intracontinental orogen that started to uplift in the Middle Miocene due to E-W convergence between the Maracaibo block to the northwest and the Guyana shield to the southeast. Oblique collision resulted in strain partitioning accommodated by (1) transverse shortening along thrust faults bounding the belt on both flanks, (2) right-lateral slip along the Bocono fault running more or less along the chain axis and (3) tectonic escape of the Trujillo block moving towards the NE in between the Bocono and the N-S-striking sinistral Valera faults. Even though the surface geology of the Venezuelan Andes is well known, its structure at depth remains a matter of debate. Among the mechanisms that have proposed to account for the crustal architecture and evolution of the mountain belt, we develop the idea that the deformation process in this orogen is consistent with a model of orogenic float where the upper crust is decoupled from its underlying lithosphere above a large-scale mid-crustal detachment zone. According to this model, all the major faults involved in the strain partitioning sole into the detachment horizon and may therefore be considered as upper crustal faults. The integration of the orogenic float into a coherent evolutionary model provides further insight on both the crustal structure of the Venezuelan Andes and on the tectonic history of the region. A major reorganization in the crust occurred in the Early Pliocene when the Maracaibo block penetrated as a wedge into the Guyana crust. This event was accompanied by a rapid uplift of the Venezuelan Andes in association with the NE-ward crustal escape of the Trujillo block whose motion is accompanied by the lateral spreading of the upper crust.

  9. Spatial and temporal patterns of exhumation across the Venezuelan Andes: Implications for Cenozoic Caribbean geodynamics

    NASA Astrophysics Data System (ADS)

    Bermúdez, Mauricio A.; Kohn, Barry P.; van der Beek, Peter A.; Bernet, Matthias; O'Sullivan, Paul B.; Shagam, Reginald

    2010-10-01

    The Venezuelan Andes formed by complex geodynamic interaction between the Caribbean Plate, the Panamá Arc, the South American Plate and the continental Maracaibo block. We study the spatial and temporal patterns of exhumation across the Venezuelan Andes using 47 new apatite fission track (AFT) ages as well as topographic analyses. This approach permits the identification of at least seven tectonic blocks (Escalante, Cerro Azul, Trujillo, Caparo, Sierra Nevada, Sierra La Culata and El Carmen blocks) with contrasting exhumation and cooling histories. The Sierra Nevada, Sierra La Culata and El Carmen blocks, located in the central part of the Venezuelan Andes and separated by the Boconó fault system, cooled rapidly but diachronously during the late Miocene-Pliocene. Major surface uplift and exhumation occurred in the Sierra Nevada block since before 8 Ma. A second phase of uplift and exhumation affected the El Carmen and Sierra La Culata blocks to the north of the Boconó fault during the late Miocene-Pliocene. The highest topography and steepest relief of the belt coincides with these blocks. The Caparo and Trujillo blocks, located at the northeastern and southwestern ends of the orogen, cooled more slowly from the Oligocene to the late Miocene. These blocks are characterized by significantly lower mean elevations and slightly lower mean slopes than the central blocks. Unraveling the cooling history of the individual blocks is important to better understand the control of preexisting faults and regional Caribbean geodynamics on the evolution of the Venezuelan Andes. Our data indicate a strong control of major preexisting fault zones on exhumation patterns and temporal correlation between phases of rapid exhumation in different blocks with major tectonic events (e.g., collision of the Panamá arc; rotation of the Maracaibo block).

  10. Toward quantifying geomorphic rates of crustal displacement, landscape development, and the age of glaciation in the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Wesnousky, Steven G.; Aranguren, Reina; Rengifo, Martin; Owen, Lewis A.; Caffee, Marc W.; Murari, Madhav Krishna; Pérez, Omar J.

    2012-03-01

    We present the results of dating glacial landforms in Venezuela using 10Be terrestrial cosmogenic nuclide (TCN) analysis and optical stimulated luminescence (OSL). Boulders on the La Victoria and Los Zerpa moraines of the Sierra Nevada that mark the extent of the local last glacial maximum (LLGM) yield 10Be TCN surface exposure ages of 16.7 ± 1.4 ka (8 samples). About 25 km to the west in the drainage basin of the Río Mucujún, 10Be TCN dates for boulders on moraines at La Culata in the Sierra Nevada Norte yield a younger average age of 15.2 ± 0.9 ka (8 samples). The data suggest that glaciation across the Venezuelan Andes during the LLGM was asynchronous. The LLGM in Venezuela may be broadly concurrent with Heinrich Event 1 at ~ 16.8 ka, implying that glaciation here is dominantly temperature driven. A moraine inset into the older laterofrontal moraines of La Culata has an age of 14.1 ± 1.0 ka (5 samples); it may have been deposited by a small Late Glacial readvance. Right-lateral offsets of the La Victoria and Los Zerpa moraines by the Boconó fault are each ~ 100 m. The 10Be TCN based Boconó fault slip rate is about <~5.5 to 6.5 mm a- 1, notably less than the total right-lateral slip of 12 ± 2 mm a- 1 of shear documented across the Andes from geodesy. The 10Be TCN dating of boulders on a faulted alluvial fan along the northwestern range front at Tucanízón yields a late Pleistocene uplift rate of the Andes at between ~ 1.7 ± 0.7 mm a- 1. Glacial outwash has produced valley-fill sequences within the central Andean valley along the trace of the Boconó fault and Río Chama. The valley-fill has been incised to produce the ‘meseta', a terrace surface that sits > 100 m above the Río Chama and on which the major city of Mérida is built. Geomorphic observations indicate that the meseta deposits were largely derived from the glaciers of La Culata. The OSL dating suggests that the final aggradation of the valley-fill deposits occurred rapidly over a period of

  11. Investigations on vertical crustal movements in the Venezuelan Andes by gravimetric methods

    NASA Technical Reports Server (NTRS)

    Drewes, H.

    1978-01-01

    A precise gravimetric network has been installed in the Venezuelan Andes to study eventual gravity changes due to vertical tectonic movements. The design and the measurements of the network are described and the accuracy is estimated. In the center of the region a local gravity network has been reobserved three times. The detected variations are discussed. In order to obtain a genuine statement as far as possible about the significance of observed gravity changes, requirements for the procedure of monitoring precise gravity networks are pointed out.

  12. Structural Evolution of the Central Venezuelan Andes: Changes From Compression to Strike-slip and Extension

    NASA Astrophysics Data System (ADS)

    Hervouet, Y.; Dhont, D.; Backe, G.

    2006-12-01

    The Venezuelan Andes form a N50°E-trending belt extending from the colombian border in the SW to the Caribbean sea in the NE. The belt is 100 km wide and its highest summits reach 5000 m in its central part. Uplift of the belt is a consequence of the relative convergence between the triangular-shaped Maracaibo crustal block on the west and the Guyana shield belonging to South America. The Maracaibo block is cut by a series of strike-slip faults separating several crustal units. Among these, the easternmost Trujillo triangular block is limited on the west by the N-S left-lateral Valera fault and on the south-east by the NE-trending right-lateral Bocono fault. Our methodology, based on the analysis of radar satellite and digital elevation model imagery and implemented by structural field work and the compilation of seismotectonic data, presents a new understanding of the tectonic evolution of the Venezuelan Andes during the Neogene-Quaternary. We have characterized three stages of deformation. The first, Mio-Pliocene in age, corresponds to the NW-SE Andean compression responsible for the uplift of the Venezuelan Andes. The second tectonic stage is consitent with a strike-slip regime of deformation marked by shearing along the Bocono and Valera faults and hence individualizing the Trujillo block, which has been cut into two smaller triangular wedges. This strike-slip faulting- dominated compressional-extensional tectonic regime started at some point between the Pliocene and the Quaternary and allowed the Trujillo crustal block to move towards the NE. The third stage of deformation corresponds to extension in the Trujillo block and is still active today. The present-day distribution of the deformation in the Venezuelan Andes is consistent with strain partitioning. While compression is restricted on both flanks of the belt, strike-slip and extension occurs in the central part of the mountain range. Extension is associated with the motion of crustal blocks moving

  13. Active faulting in the Southwestern Venezuelan Andes and Colombia borderland

    SciTech Connect

    Singer, A.; Beltran, C.; Lugo, M. , Caracas )

    1993-02-01

    In the southern Andes, the Bocono fault shows a progressive disactivation of its right lateral movement, resulting from its attenuation against the transversal system of Bramon and its kinematic connection to the [open quotes]Pamplona indenter,[close quotes] considered as a part of the plate boundary between the Caribbean and South America. Near the Colombian frontier, the velocity of Bocono fault is probably less than 1 mm/yr. Such a decrease is explained because an increasing amount of the 1 cm/yr slip movement of the northern part of the fault is absorbed through a complex branching of the active trace, southwest Merida. Another significative amount of the rate movement of Bocono fault, considered as plate boundary, results absorbed by subparallel active faulting systems located to the east (Uribante and Caparo Systems) and to the west sides (San Simon-Seboruco, and San Pedro-Aguas Calientes-La Don Juana systems). The last system, extending beyond the frontier, shows a particular seimotectonic importance, as a probable source of the 1875 Cucata earthquake. In this way, the weight of the southwestern end of Bocono fault as a seismic source loses importance respect to the northern segment located between la Grita and Merida where the 1610 and 1894 earthquakes occurred, and also as compared to the faults that define the [open quotes]Pamplona indenter[close quotes] like probable source for several other destructive earthquakes.

  14. Orogenic Float Model: an Explanation for the Dynamics of the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Monod, B.; Dhont, D.; Hervouet, Y.

    2008-12-01

    The Venezuelan (or Merida) Andes are a NE-trending intracontinental orogen that started to rise from the late Miocene due to the E-W far field convergence between the Maracaibo block to the northwest and the Guyana shield to the southeast. Oblique convergence is responsible for strain partitioning with thrusting along both foreland basins and right-lateral strike-slip faulting along the NE-SW Bocono fault cutting the Venezuelan Andes along-strike. The central part of the belt is also cut by the N-S left-lateral strike-slip Valera fault that branches the Bocono fault in the triple junction geometry, favoring the crustal escape of the Trujillo triangular block towards the NE. Onset of strike-slip motion along major faults and their geometry at depth remains a matter of debate. Our work, based on the integration of geologic and geophysical data aims to better constrain both the geometry and the tectonic evolution of the major tectonic structures. We use the orogenic float model (Oldow et al., 1990) as a first hypothesis to construct two NW-SE trans-Andean crustal scale balanced sections. The late Neogene-Quaternary shortening varies from 40 km in the south to 30 km in the north across the Trujillo block, indicating that a quarter of the deformation seems to be absorbed by the tectonic escape process. The cross-sections served also as the basis for the building of a 3-D geologic model of the Venezuelan Andes, permitting to clearly understand the link and geometry of the faults at depth. The decollement level used for the orogenic float model, located at 20 km depth, is crucial for the motion of the Trujillo block. Both the Bocono and Valera faults have listric shapes connecting to the decollement level. The connexion of the two fault surfaces forms a hinge line dipping towards the north in a geometry favoring the escape of the Trujillo block and allowing the gravity forces to play an important role in the process. Oldow J. S., Bally A. W., Ave Lallemant H. G., 1990

  15. Trench investigation along the Merida section of the Bocono fault (central Venezuelan Andes), Venezuela

    USGS Publications Warehouse

    Audemard, F.; Pantosti, D.; Machette, M.; Costa, C.; Okumura, K.; Cowan, H.; Diederix, H.; Ferrer, C.

    1999-01-01

    The Bocono fault is a major NE-SW-trending, dextral fault that extends for about 500 km along the backbone of the Venezuelan Andes. Several large historical earthquakes in this region have been attributed to the Bocono fault, and some of these have been recently associated with specific parts through paleoseismologic investigations. A new trench study has been performed, 60 km to the northeast of Merida in the central Venezuelan Andes, where the fault forms a releasing bend, comprising two conspicuous late Holocene fault strands that are about 1 km apart. The southern and northern strands carry about 70% and 30% (respectively) of the 7-10 mm/yr net slip rate measured in this sector, which is based on a 40 vs. 85-100 m right-lateral offset of the Late Pleistocene Los Zerpa moraines. A trench excavated on the northern strand of the fault (near Morros de los Hoyos, slightly northeast of Apartaderos) across a twin shutter ridge and related sag pond exposed two main fault zones cutting Late Pleistocene alluvial and Holocene peat deposits. Each zone forms a shutter ridge with peat deposits ponded against the uplifted block. The paleoearthquake reconstruction derived from this trench allow us to propose the occurrence of at least 6-8 earthquakes in the past 9000 yr, yielding a maximum average recurrence interval of about 1100-1500 yr. Based on the northern strands average slip rate (2.6 mm/yr), such as earthquake sequence should have accommodated about 23 m of slip since 9 ka, suggesting that the maximum slip per event ranges between 3 and 4 m. No direct evidence for the large 1812 earthquake has been found in the trench, although this earthquake may have ruptured this section of the fault. Further paleoseismic studies will investigate the possibility that this event occurred in the Bocono fault, but ruptured mainly its southern strand in this region.

  16. Palynological signal of the Younger Dryas in the tropical Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Rull, Valentí; Stansell, Nathan D.; Montoya, Encarni; Bezada, Maximiliano; Abbott, Mark B.

    2010-11-01

    The occurrence, or not, of the Younger Dryas cold reversal in the tropical Andes remains a controversial topic. This study reports a clear signal for this event in the Venezuelan Andes, employing high-resolution palynological analysis of a well-dated sediment core from Laguna de Los Anteojos, situated around 3900 m elevation, within grass páramo vegetation. The lake is surrounded by some Polylepis forests which are close to their upper distribution limit. The section of the core discussed here is 150-cm long and dated between about 14.68 and 9.35 cal kyr BP, using a polynomial age-depth model based on six AMS radiocarbon dates. Between 12.86 and 11.65 cal kyr BP, an abrupt shift occurred in the pollen assemblage, manifested by a decline of Podocarpus, Polylepis and Huperzia, combined with an increase in Poaceae and Asteraceae. The aquatic pteridophyte Isoëtes also decreased and disappeard, and the algae remains show their minimum values. Pollen assemblages from the Younger Dryas interval show maximum dissimilarity values compared with today's pollen assemblage, and are more similar to modern analogs from superpáramo vegetation, growing at elevations 400-500 m higher. A lowering of vegetation zones of this magnitude corresponds to a temperature decline of between 2.5 and 3.8 °C. During this colder interval lake levels may have been lower, suggesting a decrease in available moisture. The vegetation shift documented in Anteojos record between 12.86 and 11.65 cal kyr BP is comparable to the El Abra Stadial in the Colombian Andes but it differs in magnitude. The Anteojos shift is better dated and coincides with the Younger Dryas chron as recorded in the Cariaco Basin sea surface temperature reconstructions and records of continental runoff, as well as in the oxygen isotope measurements from the Greenland ice cores. When compared to other proxies of quasi-immediate response to climate, the time lag for the response of vegetation to climate is found to be negligible

  17. 3D geological modeling of the Trujillo block: Insights for crustal escape models of the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Dhont, Damien; Monod, Bernard; Hervouët, Yves; Backé, Guillaume; Klarica, Stéphanie; Choy, José E.

    2012-11-01

    The Venezuelan Andes form a N50°E-trending mountain belt extending from the Colombian border in the SW to the Caribbean Sea in the NE. The belt began to rise since the Middle Miocene in response to the E-W collision between the Maracaibo block to the NW and the Guyana shield belonging to South America to the SE. This oblique collision led to strain partitioning with (1) shortening along opposite-vergent thrust fronts, (2) right-lateral slip along the Boconó fault crossing the belt more or less along-strike and (3) crustal escape of the Trujillo block moving towards the NE in between the Boconó fault and the N-S-striking left-lateral Valera fault. The geology of the Venezuelan Andes is well described at the surface, but its structure at depth remains hypothetic. We investigated the deep geometry of the Mérida Andes by a 3D model newly developed from geological and geophysical data. The 3D fault model is restricted to the crust and is mainly based on the surface data of outcropping fault traces. The final model reveals the orogenic float concept where the mountain belt is decoupled from its underlying lithosphere over a horizontal décollement located either at the upper/lower crust boundary. The reconstruction of the Boconó and Valera faults results in a 3D shape of the Trujillo block, which floats over a mid-crustal décollement horizon emerging at the Boconó-Valera triple junction. Motion of the Trujillo block is accompanied by a widespread extension towards the NE accommodated by normal faults with listric geometries such as for the Motatan, Momboy and Tuñame faults. Extension is explained by the gravitational spreading of the upper crust during the escape process.

  18. Comparison of the chemical composition of Valeriana parviflora essential oils collected in the Venezuelan Andes in two different seasons.

    PubMed

    Fernández, Sammy; Rondón, María; Rojas, Janne; Morales, Antonio; Rojas-Fermin, Luis

    2015-04-01

    The essential oils obtained by hydrodistillation of the aerial parts of Valerianaparviflora (Trevir) BM Vadillo, an endemic species of the Venezuelan Andes, collected from the same location in two different seasons (dry and rainy) of the year, were analyzed by GC/MS. The essential oil obtained during the dry season showed linalool (11.9%), eugenol (8.9%), p-menth-l-en-9-al (8.7%) and α-terpineol (7.7%) as main components, while the oil obtained from the rainy season collection showed o-xylol (16.2%), 3-methyl isovaleric acid (10.6%) and geranial (9.5%) as major compounds. Some of the differences in the composition of these oils might be due to the climatic conditions at the time of harvesting.

  19. A new species of Cryptotis (Mammalia, Eulipotyphla, Soricidae) from the Sierra de Perijá, Venezuelan-Colombian Andes

    USGS Publications Warehouse

    Quiroga-Carmona, Marcial; Woodman, Neal

    2015-01-01

    The Sierra de Perijá is the northern extension of the Cordillera Oriental of the Andes and includes part of the border between Colombia and Venezuela. The population of small-eared shrews (Mammalia, Eulipotyphla, Soricidae, Cryptotis) inhabiting the Sierra de Perijá previously was known from only a single skull from an individual collected in Colombia in 1989. This specimen had been referred to alternatively as C. thomasi and C. meridensis, but more precise definition of the known Colombian and Venezuelan species of Cryptotis has since excluded the Sierra de Perijá population from any named species. The recent collection of a specimen from the Venezuelan slope of Sierra de Perijá, prompted us to re-evaluate the taxonomic status of this population and determine its relationship with other Andean shrews. Our examination of the available specimens revealed that they possess a unique suite of morphological and morphometrical characters, and we describe the Sierra de Perijá population as a new species in the South American C. thomasi species group. Recognition of this new species adds to our knowledge of this genus in South America and to the biodiversity of the Sierra de Perijá.

  20. Recent trends in human migrations: the case of the Venezuelan Andes.

    PubMed

    Suarez, M M; Torrealba, R

    1982-01-01

    Changes in world capitalism caused prices of traditional raw materials to fall and new energy demands to arise at the end of the 19th and beginning of the 20th century. The Andean countries witnessed the fall in the value of their exports and began to receive large flows of foreign investment in mining and industry. Consequently, urban economies were strengthened and demographic patterns were changed. This led to the internal migrations and to a process of social change. These consequences are summarized from relevant studies focusing on Ecuador, Colombia, and Venezuela. Since the 1960s a compendium of information has become available which highlights the causes of the migration, migration patterns, the composition of migratory movements, and the mechanisms that the migrant uses to establish himself/herself in the city. Preston (1969) distinguished 2 migratory patterns in Ecuador: rural to urban, with migratory flows from the rural areas to urban centers and new industrial cities that experienced development and high demand for unskilled labor at comparatively high wages: and rural to rural, based on the movement of population from depressed rural areas to other areas in which programs for colonization or commercial agriculture have been promoted. In a study of Colombia, McGreevey (1968) identifies the lack of cultivatable land, rural violence in certain departments, and other economic and family causes as the principal factors that induced migrations to the cities. The study emphasizes that the predominant model of movement relates to "fill in" migration. The spatial mobility of the Venezuelan Andean population was initially outlined in a voluminous report on economic and social problems of the region (1954). The study indicates that during the intercensal period 1941-50 cities grew much more rapidly than rural "municipos" and that the drive to find employment and earn a living were the most important motives in the movement of peasants to the cities. All of the

  1. Spatial and temporal relationships between compression, strike-slip and extension in the Central Venezuelan Andes: Clues for Plio-Quaternary tectonic escape

    NASA Astrophysics Data System (ADS)

    Backé, Guillaume; Dhont, Damien; Hervouët, Yves

    2006-10-01

    The geometry of tectonic structures, attributed to the Neogene-Quaternary time interval, is described in the active setting of the Venezuelan Andes. Our methodology is based on the analysis of radar satellite and Digital Elevation Model imagery, complemented by structural fieldwork and the compilation of seismotectonic data to make a structural analysis on a regional scale. Radar images provide first class data for morphostructural analysis in areas of dense vegetation and frequent cloud covering, like the Venezuelan Andes. We focused our analysis in the Burbusay-Río Momboy and Boconó faults corner located in the central part of the belt. We have described three stages of deformation during the Neogene-Quaternary. The first one, Mio-Pliocene in age, is a NW-SE compression responsible for the uplift of the Venezuelan Andes. The second tectonic stage corresponds to a strike-slip regime of deformation marked by shearing along the Boconó, Burbusay and Valera faults, which separates two triangular wedges in the larger Trujillo block. This strike-slip faulting-dominated compressional-extensional tectonic regime allowed the Trujillo crustal block to move towards the NE. Wrenching has therefore started at some point between the Pliocene and the Quaternary. These two tectonic events are consistent with ongoing strain partitioning in the Venezuelan Andes. The third stage corresponds to extensional deformation limited to the Trujillo block and is still active today. Extension is associated with the motion of crustal blocks moving relative to each other, probably above the upper-lower crust boundary. Such extensional deformation can be understood considering that the crust extends and stretches at the same time as it moves towards the NE. The combination of both horizontal lateral motion and extension is characteristic of a tectonic escape process. The northeastward escape of the Trujillo block, which belongs to the larger North Andes block, occurs as a result of the

  2. Metre-scale cyclicity in Permian ramp carbonates of equatorial Pangea (Venezuelan Andes): Implications for sedimentation under tropical Pangea conditions

    NASA Astrophysics Data System (ADS)

    Laya, Juan Carlos; Tucker, Maurice E.; Perez-Huerta, Alberto

    2013-06-01

    Palmarito strata in the mid-Permian of the Venezuelan Andes show three different types of metre-scale cycle: Type A cycles are mixed clastic-carbonate, shallowing-upward peritidal cycles. The upper boundaries of the cycles are exposure surfaces with calcrete. This kind of cycle shows a significant degree of randomness in its thickness pattern and this is attributed to an autocyclic origin through tidal-flat progradation, and variations in carbonate productivity and clastic input to the depositional area. Type B cycles consist entirely of shallow subtidal facies with a shallowing-upward arrangement and an alternation between heterozoan and photozoan assemblages. Type C cycles were deposited in a middle to outer ramp setting and are characterized by a heterozoan assemblage and shallowing-upward trends that includes spiculitic wackestone-packstone passing up into neomorphic bioclastic wackestone or bioclastic crinoidal-bryozoan wackestone-packstone. All cycles are interpreted as 4th-5th order (104 to 105 years duration) and some can be linked to Milankovitch orbital rhythms, notably short eccentricity (~ 100,000 years). Overall, the origin of the Palmarito cycles was a complex combination of autocyclic and allocyclic controls; however, the evidence suggests that cycles in the lower part of the succession were dominated more by autocyclic processes whereas those in the upper part were more the result of allocyclic controls. Climate-driven processes, such as migration of the intertropical convergence one and the waxing and waning of polar ice-caps, had significant effects on deposition of the Palmarito succession and the cycles therein, controlling the clastic sediment supply, nutrient availability and thus carbonate production, and sea-level change, and these factors determined the vertical stacking pattern of the cycles.

  3. Stratotype for the Mérida Glaciation at Pueblo Llano in the northern Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Mahaney, W. C.; Milner, M. W.; Voros, J.; Kalm, V.; Hütt, G.; Bezada, M.; Hancock, R. G. V.; Aufreiter, S.

    2000-12-01

    The Mérida Glaciation (cf. Wisconsinan, Weichselian) as proposed by Schubert (1974b) culminated at about 18 ka during the last glacial maximum (LGM) and ended at about 13 ka as indicated by 14C dating and correlation with the Cordillera Oriental of Colombia. Moraines of an early stade of Mérida Glaciation reached to 2800 m a.s.l. and were largely overrun or eradicated by the maximum Wisconsinan advance (LGM); where they outcrop, the older moraines are characterized by eroded, weathered glacial diamictons and outwash fans. At Pueblo Llano in the central Mérida Andes (Cordillera de Trujillo), older to younger beds of contorted glacitectonized diamict, overlying beds of bouldery till and indurated outwash, all belong to the early Mérida stade. Overlying the early Mérida stade, deposits of rhythmically bedded glaciolacustrine sediments are in turn overlain with contorted sand and silt beds capped with outwash. Above the outwash terrace a loop moraine of LGM age completely encircles the margins of the basin. A stream cut exposed by catastrophic (tectonic or surge?) release of meltwater displays a lithostratigraphic succession that is bereft of organic material for radiocarbon dating. Five optically-stimulated luminescence (OSL) dates place the maximum age of the lowest till at 81 ka. Particle size distributions allow clear distinctions between major lithic units. Heavy mineral analysis of the middle and lower coarse units in the section provide information on sediment sourcing and on major lithostratigraphic divisions. Trace element concentrations provide information on the relative homogeneity of the deposits. The HREE (heavy rare earth element) concentrations allow discrimination of the lower till from the rest of the section; the LREE (light rare earth element) concentrations highlight differences between the lower till, LGM till, and the rest of the section.

  4. Tectonic, volcanic, and climatic geomorphology study of the Sierras Pampeanas Andes, northwestern Argentina

    NASA Technical Reports Server (NTRS)

    Bloom, A. L.; Strecker, M. R.; Fielding, E. J.

    1984-01-01

    A proposed analysis of Shuttle Imaging Radar-B (SIR-B) data extends current research in the Sierras Pampeanas and the Puna of northwestern Argentina to the determination - by the digital analysis of mountain-front sinuousity - of the relative age and amount of fault movement along mountain fronts of the late-Cenozoic Sierras Pampeanas basement blocks; the determination of the age and history of the boundary across the Andes at about 27 S latitude between continuing volcanism to the north and inactive volcanism to the south; and the determination of the age and extent of Pleistocene glaciation in the High Sierras, as well as the comparative importance of climatic change and tectonic movements in shaping the landscape. The integration of these studies into other ongoing geology projects contributes to the understanding of landform development in this active tectonic environment and helps distinguish between climatic and tectonic effects on landforms.

  5. A new species of Andean poison frog, Andinobates (Anura: Dendrobatidae), from the northwestern Andes of Colombia.

    PubMed

    Amézquita, Adolfo; Márquez, Roberto; Medina, Ricardo; Mejía-Vargas, Daniel; Kahn, Ted R; Suárez, Gustavo; Mazariegos, Luis

    2013-01-01

    The poison frogs of the Colombian Andes, Pacific lowlands and Panama have been recently recognized as a new, monophyletic and well-supported genus: Andinobates. The species richness and distribution within Andinobates remain poorly understood due to the paucity of geographic, genetic and phenotypic data. Here we use a combination of molecular, bioacoustic and morphometric evidence to describe a new species of Andean poison frog: Andinobates cassidyhornae sp. nov. from the high elevation cloud forests of the Colombian Cordillera Occidental, in the northwestern Andes. The new species is associated to the bombetes group and characterized by a unique combination of ventral and dorsal color patterns. Data on 1119 bp from two mitochondrial markers allowed us to reject the null hypotheses that A. cassidyhornae sp. nov. is part of the phenotypically similar and geographically less distant species: A. opisthomelas, A. virolinensis or A. bombetes. The best available phylogenetic trees and the genetic distance to other Andinobates species further support this decision. Altogether, the advertisement call parameters unambiguously separated A. cassidyhornae sp. nov. calls from the calls of the three closest species. The new species adds to a poorly known and highly endangered genus of poison frogs that requires further studies and urgent conservation measures.

  6. Andes

    Atmospheric Science Data Center

    2013-04-18

    article title:  The Andes in True Color, Stereo, and Relief     Left: True Color Image View true color full resolution image in JPEG format ... view afforded by the stereo anaglyph image (viewed with red/blue glasses, with the red lens over the left eye), it is possible to ...

  7. New dinosaur (Theropoda, stem-Averostra) from the earliest Jurassic of the La Quinta formation, Venezuelan Andes

    PubMed Central

    Langer, Max C.; Rincón, Ascanio D.; Ramezani, Jahandar; Solórzano, Andrés; Rauhut, Oliver W. M.

    2014-01-01

    Dinosaur skeletal remains are almost unknown from northern South America. One of the few exceptions comes from a small outcrop in the northernmost extension of the Andes, along the western border of Venezuela, where strata of the La Quinta Formation have yielded the ornithischian Laquintasaura venezuelae and other dinosaur remains. Here, we report isolated bones (ischium and tibia) of a small new theropod, Tachiraptor admirabilis gen. et sp. nov., which differs from all previously known members of the group by an unique suite of features of its tibial articulations. Comparative/phylogenetic studies place the new form as the sister taxon to Averostra, a theropod group that is known primarily from the Middle Jurassic onwards. A new U–Pb zircon date (isotope dilution thermal-ionization mass spectrometry; ID-TIMS method) from the bone bed matrix suggests an earliest Jurassic maximum age for the La Quinta Formation. A dispersal–vicariance analysis suggests that such a stratigraphic gap is more likely to be filled by new records from north and central Pangaea than from southern areas. Indeed, our data show that the sampled summer-wet equatorial belt, which yielded the new taxon, played a pivotal role in theropod evolution across the Triassic–Jurassic boundary. PMID:26064540

  8. Dynamics and Upper Mantle Structure Beneath the Northwestern Andes: Subduction Segments, Moho Depth, and Possible Relationships to Mantle Flow

    NASA Astrophysics Data System (ADS)

    Monsalve, G.; Yarce, J.; Becker, T. W.; Porritt, R. W.; Cardona, A.; Poveda, E.; Posada, G. A.

    2014-12-01

    The northwestern South American plate shows a complex tectonic setting whose causes and relationship to mantle structure are still debated. We combine different techniques to elucidate some of the links between slabs and surface deformation in Colombia. Crustal structure beneath the Northern Andes was inferred from receiver functions where we find thicknesses of nearly 60 km beneath the plateau of the Eastern Cordillera and underneath the southern volcanic area of the Central Cordillera. We infer that such crustal thickening resulted from shortening, magmatic addition, and accretion-subduction. Analyses of relative teleseismic travel time delays and estimates of residual surface topography based on our new crustal model suggest that there are at least two subduction segments underneath the area. The Caribbean slab lies at a low angle beneath northernmost Colombia and steepens beneath the Eastern Cordillera. Such steepening is indicated by negative travel time relative residuals in the area of the Bucaramanga Nest, implying a cold anomaly in the upper mantle, and by positive residual topography just off the east of this area, perhaps generated by slab-associated return flow. Results for the western Andes and the Pacific coastal plains are consistent with "normal" subduction of the Nazca plate: travel time relative residuals there are predominantly positive, and the residual topography shows an W-E gradient, going from positive at the Pacific coastline to negative at the Magdalena Valley, which separates the eastern cordillera from the rest of the Colombian Andean system. Azimuthal analysis of relative travel time residuals further suggests the presence of seismically slow materials beneath the central part of the Eastern Cordillera. Azimuthal anisotropy from SKS splitting in that region indicates that seismically fast orientations do not follow plate convergence, different from what we find for the western Colombian Andes and the Caribbean and Pacific coastal plains

  9. Geological history of the Cretaceous ophiolitic complexes of northwestern South America (Colombian Andes)

    NASA Astrophysics Data System (ADS)

    Bourgois, Jacques; Toussaint, Jean-François; Gonzalez, Humberto; Azema, Jacques; Calle, Bernardo; Desmet, Alain; Murcia, Luis A.; Acevedo, Alvaro P.; Parra, Eduardo; Tournon, Jean

    1987-12-01

    The Western Cordillera of Colombia was formed by intense alpine-type nappe-forming folding and thrusting. The Cretaceous (80-120 Ma B.P.) tholeiitic material of the Western Cordilleran nappes has been obducted onto the Paleozoic and Precambrian polymetamorphic micaschists and gneiss of the Central Cordillera. Near Yarumal, the Antioquia batholith (60-80 Ma B.P.) intrudes both obducted Cretaceous oceanic material and the polymetamorphic basement rock of the Central Cordillera. Therefore, nappe emplacement and obduction onto the Central Cordillera occurred during Late Senonian to Early Paleocene. The nappes travelled from northwest to southeast so that the highest unit, the Rio Calima nappe therefore has the most northwestern source, whereas the lowest units originated from a more southeastward direction. Sedimentological analysis of the volcanoclastic and sandy turbidite material from each unit suggests a marginal marine environment. During Cretaceous times the opening of this marginal sea, from now on called the "Colombia marginal basin", probably originated by detachment of a block from the South American continent related to the Farallon-South America plate convergence. In the Popayan area (southern Colombia), the Central Cordilleran basement exhibits glaucophane schist facies metamorphism. This high pressure low temperature metamorphism is of Early Cretaceous (125 Ma B.P.) age and is related to an undated metaophiolitic complex. The ophiolitic material originating from the Western Cordilleran is thrust over both the blueschist belt and the metaophiolitic complex. These data suggest that the "Occidente Colombiano" suffered at least two phases of ophiolitic obduction during Mesozoic time.

  10. Paleozoic evolution of active margin basins in the southern Central Andes (northwestern Argentina and northern Chile)

    NASA Astrophysics Data System (ADS)

    Bahlburg, H.; Breitkreuz, C.

    The geodynamic evolution of the Paleozoic continental margin of Gondwana in the region of the southern Central Andes is characterized by the westward progression of orogenic basin formation through time. The Ordovician basin in the northwest Argentinian Cordillera Oriental and Puna originated as an Early Ordovician back-arc basin. The contemporaneous magmatic arc of an east-dipping subduction zone was presumably located in northern Chile. In the back-arc basin, a ca. 3500 meter, fining-up volcaniclastic apron connected to the arc formed during the Arenigian. Increased subsidence in the late Arenigian allowed for the accomodation of large volumes of volcaniclastic turbidites during the Middle Ordovician. Subsidence and sedimentation were caused by the onset of collision between the para-autochthonous Arequipa Massif Terrane (AMT) and the South American margin at the Arenigian-Llanvirnian transition. This led to eastward thrusting of the arc complex over its back-arc basin and, consequently, to its transformation into a marine foreland basin. As a result of thrusting in the west, a flexural bulge formed in the east, leading to uplift and emergence of the Cordillera Oriental shelf during the Guandacol Event at the Arenigian-Llanvirnian transition. The basin fill was folded during the terminal collision of the AMT during the Oclóyic Orogeny (Ashgillian). The folded strata were intruded post-tectonically by the presumably Silurian granitoids of the "Faja Eruptiva de la Puna Oriental." The orogeny led to the formation of the positive area of the Arco Puneño. West of the Arco Puneño, a further marine basin developed during the Early Devonian, the eastern shelf of which occupied the area of the Cordillera Occidental, Depresión Preandina, and Precordillera. The corresponding deep marine turbidite basin was located in the region of the Cordillera de la Costa. Deposition continued until the basin fill was folded in the early Late Carboniferous Toco Orogeny. The basin

  11. Diversity of culturable bacteria recovered from Pico Bolívar's glacial and subglacial environments, at 4950 m, in Venezuelan tropical Andes.

    PubMed

    Rondón, Johnma; Gómez, Wileidy; Ball, María M; Melfo, Alejandra; Rengifo, Marcos; Balcázar, Wilvis; Dávila-Vera, Delsy; Balza-Quintero, Alirio; Mendoza-Briceño, Rosa Virginia; Yarzábal, Luis Andrés

    2016-11-01

    Even though tropical glaciers are retreating rapidly and many will disappear in the next few years, their microbial diversity remains to be studied in depth. In this paper we report on the biodiversity of the culturable fraction of bacteria colonizing Pico Bolívar's glacier ice and subglacial meltwaters, at ∼4950 m in the Venezuelan Andean Mountains. Microbial cells of diverse morphologies and exhibiting uncompromised membranes were present at densities ranging from 1.5 × 10(4) to 4.7 × 10(4) cells/mL in glacier ice and from 4.1 × 10(5) to 9.6 × 10(5) cells/mL in subglacial meltwater. Of 89 pure isolates recovered from the samples, the majority were eurypsychrophilic or stenopsychrophilic, according to their temperature range of growth. Following analysis of their 16S rDNA nucleotidic sequence, 54 pure isolates were assigned to 23 phylotypes distributed within 4 different phyla or classes: Beta- and Gammaproteobacteria, Actinobacteria, and Bacteroidetes. Actinobacteria dominated the culturable fraction of glacier ice samples, whereas Proteobacteria were dominant in subglacial meltwater samples. Chloramphenicol and ampicillin resistance was exhibited by 73.07% and 65.38%, respectively, of the subglacial isolates, and nearly 35% of them were multiresistant. Considering the fast rate at which tropical glaciers are melting, this study confirms the urgent need to study the microbial communities immured in such environments.

  12. Soil stratigraphy and plant soil interactions on a Late Glacial Holocene fluvial terrace sequence, Sierra Nevada National Park, northern Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Mahaney, William C.; Dirszowsky, Randy W.; Milner, Michael W.; Harmsen, Rudolf; Finkelstein, Sarah A.; Kalm, Volli; Bezada, Maximilano; Hancock, R. G. V.

    2007-01-01

    Analysis of a flight of alluvial terraces in the Sierra Nevada National Park near Pico Mucuñuque in the Eastern Mérida Andes has yielded information on geomorphic, pedogenic, and vegetational changes from Late Glacial time to the present. The terraces formed in large part due to stream incision/migration triggered by neotectonic uplift (>7000 yr BP) of a Late Glacial/Early Holocene glaciolacustrine lithosequence and, with the exception of the oldest/highest terrace, exhibit near-uniform lithology/parent materials. Soils developed in the terrace materials range from thin, weakly developed profiles (O/C/Cu horizons) to Entisols with O/Ah/Cox/Cu horizons and similar buried counterparts representing former short periods of floodplain stability or slow aggradation. The buried soils provide organic-rich material that yields radiocarbon ages, which provide time constraints on individual pedons and the geomorphic development of the site. Iron and aluminum extracts of soil matrix material provide information on the formation and accumulation of goethite and hematite, the relative accumulation of ferrihydrite (gain/loss), and the downward translocation of organically complexed Al as a function of soil development and age. SEM analysis of heavy mineral grains indicates varying material sources and degrees of weathering in the soil chronosequence. A qualitative study of plant functional types across the terrace sequence shows that older surfaces support greater plant diversity. The study also suggests ways in which the plant communities influence soil development at the site through varying organic matter inputs and varying soil moisture use by specific species (e.g., ferns on the oldest terrace), which may explain the absence of B horizons in the Late Pleistocene/Early Holocene soils.

  13. Compositional Trends of Cretaceous Conglomerate Provenance: Tracing The Evolving Nature of Tectonic Environments in the Northwestern Colombian Andes

    NASA Astrophysics Data System (ADS)

    Patino, A. M.; Zapata, S.; Cardona, A.; Jaramillo, J. S.

    2014-12-01

    The composition and provenance of the sedimentary record is a sensible marker of the evolving nature of source , basin paleogeography and tectonic assemblage. The Cretaceous geological evolution of the northern Andes is characterized by the succession of different tectonic environments that include: An early Cretaceous magmatic quiescence that follow former Jurassic arc magmatism, Albian-Aptian subduction resume and associated arc - back-arc formation and the late Cretaceous collision with an allocthonous oceanic arc that marks the beginning of the Andean orogeny. Such tectonic evolution had been mostly reconstructed from the magmatic record or the stratigraphic analysis of inland basin far from the arcs and suture zones. Along the western flank of the central cordillera outcrops two different stratigraphic units with notable differences in the provenance and timing of accumulation. The Abejorral Formation is the oldest sedimentary sequence (Albian-Aptian) that discordantly overlies the Triassic continental margin. this unit include two lithofacies clearly distinguishable, a lithofacies consist mostly of conglomerate, characterized by abundant quartz content , low compaction, rounded clasts and moderate sorting ; and the other is a interbedded of fine size sandstone, mudstone and chert; also with abundant quartz content further muscovite, containing basement and volcanic material . To the west, sedimentary rocks including within the Quebradagrande Formation conform a turbidite sequence with a well defined Bouma type succession that concordantly overlied a Campanian marine volcanic arc succession. The conglomerates associated to this unit are characterized by containing mainly sedimentary and volcanic rock fragments ,high compaction, subrounded clast, and low sorting. This sequence is overlying by the volcanic component in a concord contact. Whereas the Albian-Aptian record of the Abejorral Formation exhibit the unroofing of the continental basement and deepening of

  14. Venezuelan solution

    SciTech Connect

    Not Available

    1984-05-16

    Of the three most famous cases of internal market price subsidies, Mexico, Venezuela, and Saudi Arabia, only Saudi Arabia remains the one oil-exporting developing country persisting in this domestic price policy. Mexico took the bold decision of hiking prices several times since early 1982, but this is the first such drastic action by Venezuela. Suffering both burgeoning foreign debt and reduced oil-export revenues, Venezuela has taken the difficult decision of hiking internal market prices for two important purposes: to curtail almost rampant consumption increases, and to increase oil-industry revenues. Internal market analysts have for years voiced their concern about the consequences of maintaining the deep subsidies, and many studies have gathered dust on the shelf. It was the external shocks hitting the country broadside that finally forced the government to act: world recession, lower oil demand and prices, and the growing pressure to invest in the future of the oil industry in the face of the national foreign debt all brought an end to such a cheap, if not free, lunch for Venezuelan consumers. A chart illustrates how each of eight light petroleum product prices were increased. This issue includes the fuel price/tax series and the industrial fuel prices for May 1984 for countries of the Eastern Hemisphere.

  15. [Venezuelan Virology Network].

    PubMed

    Añez, Germán

    2005-03-01

    In November 2004, sponsored by the World Bank, the Venezuelan Foundation of Science, Technology and Innovation (Fonacit) and the Venezuelan Institute of Scientific Research (IVIC), delegates from the different virology research groups of the country, met in Caracas-Venezuela, with the aim to establish the "Venezuelan Virology Network". The symposium entitled "Molecular biology applied to virus of health importance in Venezuela", was divided into three areas, including human and animals viruses related to public health: 1) Dengue, others arboviruses and Hemorrhagic Fevers; 2) diarrhea-related and others veterinary viruses and 3) Hepatitis, HIV and others sexually transmitted viruses. This symposium allowed the delegates to evaluate the current strengths, weaknesses and needs of the different laboratories, becoming evident the necessity of developing collaborative work between the groups that share the same interests or lines of research; and also their need to exchange technical resources, human and bibliographical material and consequently, avoiding the duplication of efforts and the unnecessary cost of resources. One of the main strengths of Venezuelan virology is the presence, in most laboratories, of researchers with studies of fourth level and multidisciplinary teams of work. We aspire to achieve the raised objectives in the event, to the benefit of our virology and even more important, of our people.

  16. Venezuelan haemorrhagic fever.

    PubMed

    Salas, R; de Manzione, N; Tesh, R B; Rico-Hesse, R; Shope, R E; Betancourt, A; Godoy, O; Bruzual, R; Pacheco, M E; Ramos, B

    1991-10-26

    An outbreak of severe haemorrhagic illness began in the municipality of Guanarito, Portuguesa State, Venezuela, in September, 1989. Subsequent detailed study of 15 cases confirmed the presence of a new viral disease, designated Venezuelan haemorrhagic fever. Characteristic features are fever, toxicity, headache, arthralgia, diarrhoea, conjunctivitis, pharyngitis, leucopenia, thrombocytopenia, and haemorrhagic manifestations. Other features include facial oedema, cervical lymphadenopathy, nausea/vomiting, cough, chest or abdominal pain, and convulsions. The patients ranged in age from 6 to 54 years; all were residents of rural areas in central Venezuela, and 9 died. Infection with Guanarito virus, a newly recognised arenavirus, was shown by direct culture or by serological confirmation in all cases. Epidemiological studies suggest that the disease is endemic in some rural areas of central Venezuela and that it is rodent-borne. Venezuelan haemorrhagic fever has many similarities to Lassa fever and to the arenavirus haemorrhagic fevers that occur in Argentina and Bolivia.

  17. Group updates Gravity Database for central Andes

    NASA Astrophysics Data System (ADS)

    MIGRA Group; Götze, H.-J.

    Between 1993 and 1995 a group of scientists from Chile, Argentina, and Germany incorporated some 2000 new gravity observations into a database that covers a remote region of the Central Andes in northern Chile and northwestern Argentina (between 64°-71°W and 20°-29°S). The database can be used to study the structure and evolution of the Andes. About 14,000 gravity values are included in the database, including older, reprocessed data. Researchers at universities or governmental agencies are welcome to use the data for noncommercial purposes.

  18. ASTER Andes

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In this image of the Andes along the Chile-Bolivia border, the visible and infrared data have been computer enhanced to exaggerate the color differences of the different materials. The scene is dominated by the Pampa Luxsar lava complex, occupying the upper right two-thirds of the scene. Lava flows are distributed around remnants of large dissected cones, the largest of which is Cerro Luxsar. On the middle left edge of the image are the Olca and Parumastrato volcanoes, which appear in blue due to a lack of vegetation (colored red in this composite). This image covers an area 60 kilometers (37 miles) wide and 60 kilometers (37 miles) long in three bands of the reflected visible and infrared wavelength region. It was acquired on April 7, 2000.

    The image is located at 21 degrees south latitude, 68.3 degrees west longitude.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial

  19. VENEZUELAN EQUINE ENCEPHALOMYELITIS IN MAN

    PubMed Central

    Casals, J.; Curnen, Edward C.; Thomas, Lewis

    1943-01-01

    A filterable agent was isolated from the blood and from washings of the upper respiratory passages of a young laboratory worker during a mild, acute, febrile illness. This agent was identified as a strain of Venezuelan equine encephalomyelitis virus. Circulating specific complement-fixing and neutralizing antibodies not present in sera withdrawn during the acute phase of illness were demonstrated in sera obtained during convalescence. A fellow laboratory worker who became similarly ill simultaneously also developed during convalescence specific circulating antibodies not present prior to illness. PMID:19871301

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    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

  1. Aftermath of Venezuelan flood disaster

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    One month after several rounds of devastating floods and mudslides waterlogged parts of Venezuela in December and January, the country and government are trying to come to grips with the damage and begin reconstruction efforts. They are also trying to limit potential health risks that can arise following natural disasters. Epidemics, however, rarely occur following a disaster, according to Jean-Luc Poncelet, a doctor with the Pan American Health Organization. Between 25,000 and 50,000 people in Venezuela were killed, and about 150,000 displaced, according to local and international aid authorities. In addition,Venezuelan national authorities have declared part of the Port of La Guaira as a dangerous chemical zone because of ruptured containers of dangerous chemicals, hundreds of kilometers of the Caribbean coast have been closed to fishing and swimming because of contaminated runoff from the floods, roads remain blocked, and the lack of potable water is a key concern.

  2. Population genetic structure of Venezuelan chiropterophilous columnar cacti (Cactaceae).

    PubMed

    Nassar, Jafet M; Hamrick, J L; Fleming, Theodore H

    2003-11-01

    We conducted allozyme surveys of three Venezuelan self-incompatible chiropterophilous columnar cacti: two diploid species, Stenocereus griseus and Cereus repandus, and one tetraploid, Pilosocereus lanuginosus. The three cacti are pollinated by bats, and both bats and birds disperse seeds. Population sampling comprised two spatial scales: all Venezuelan arid zones (macrogeographic) and two arid regions in northwestern Venezuela (regional). Ten to 15 populations and 17-23 loci were analyzed per species. Estimates of genetic diversity were compared with those of other allozyme surveys in the Cactaceae to examine how bat-mediated gene dispersal affects the population genetic attributes of the three cacti. Genetic diversity was high for both diploid (P(s) = 94.1-100, P(p) = 56.7-72.3, H(s) = 0.182-0.242, H(p) = 0.161-0.205) and tetraploid (P(s) = 93.1, P(p) = 76.1, H(s) = 0.274, H(p) = 0.253) species. Within-population heterozygote deficit was detected in the three cacti at macrogeographic (F(IS) = 0.145-0.182) and regional (F(IS) = 0.057-0.174) levels. Low genetic differentiation was detected at both macrogeographic (G(ST) = 0.043-0.126) and regional (G(ST) = 0.009-0.061) levels for the three species, suggesting substantial gene flow among populations. Gene exchange among populations seems to be regulated by distance among populations. Our results support the hypothesis that bat-mediated gene dispersal confers high levels of genetic exchange among populations of the three columnar cacti, a process that enhances levels of genetic diversity within their populations.

  3. Solar modulation of Little Ice Age climate in the tropical Andes

    PubMed Central

    Polissar, P. J.; Abbott, M. B.; Wolfe, A. P.; Bezada, M.; Rull, V.; Bradley, R. S.

    2006-01-01

    The underlying causes of late-Holocene climate variability in the tropics are incompletely understood. Here we report a 1,500-year reconstruction of climate history and glaciation in the Venezuelan Andes using lake sediments. Four glacial advances occurred between anno Domini (A.D.) 1250 and 1810, coincident with solar-activity minima. Temperature declines of −3.2 ± 1.4°C and precipitation increases of ≈20% are required to produce the observed glacial responses. These results highlight the sensitivity of high-altitude tropical regions to relatively small changes in radiative forcing, implying even greater probable responses to future anthropogenic forcing. PMID:16740660

  4. A Statistical Analysis of Venezuelan Defense Spending.

    DTIC Science & Technology

    1985-03-01

    ARTS IN NATIONAL SECURITY AFFAIRS f rom the NVAL POSTGRADUATE SCHOOL March 1985 Author: Approved by: _________________________ S. Blandin, Chairman...Department of National Security f airs WWI- -. i .......... i ABSTRACT Venezuelan mil i tar) expendi tures hae beer, studieJd rriny times. Relatively...Growth In Imports-------------------------------50 7. Country Factor Scores For Factor 6: External Debt Service 1982------------------------ 51 8

  5. Tectonics and geodynamics of the Eastern Venezuelan Ranges

    SciTech Connect

    Roure, F. ); Passalacqua, H. ); Gou, I. )

    1993-02-01

    The eastern Venezuelan Ranges result from oblique convergence along the South American-Caribbean plate boundary, whose main surface expression is the El Pilar dextral strike-slip fault. Crustal scale balanced cross-sections have been here completed from available surface and subsurface data across this major transfer zone which links the oceanic subduction of the Lesser Antilles with the continental subduction of the Andes. The present geometries of the sectons show a major discrepancy between the cover and basement lengths, which could be explained by tectonic inheritance from the Tethyan margin. A careful analysis of both the chronostratigraphy and the internal geometry of the foredeep and piggy-back syntectonic deposits are also used to establish the kinematics of each individual structure. Basement involved is postulated for the Pirital Thrust which cuts previously emplaced cover structures like the El Furrial structural unit. Reactivation of ancient thrust faults occurs also at the rear of the Pirital out-of-sequence thrust in the west. As in the Alps or the Pyrenees, a high density intracrustal wedge is required to fit the gravimetric high imaged north of the Serrania; the solutions require a deep crustal root beneath the belt and a north-dipping South American Moho. A consistent geodynamical model, involving the north-dipping subduction of at least 70 km of South American continental lithosphere is thus proposed. An important strain partitioning occurs along the El Pilar Fault and underneath the deep crustal indenter (backstop), which decouples the south-verging allochthon of the Serrania from the north-dipping subducted South American lithosphere and from the eastward-migrating metamorphic belt.

  6. Seismological Parameters in the Northern Andes, Venezuela

    NASA Astrophysics Data System (ADS)

    Sobiesiak, M.; Palme de Osechas, C.; Choy, J. E.; Morandi S., M. T.; Campo, M.; Granado Ruiz, C.

    2001-12-01

    Venezuelas tectonic setting as part of the plate boundary between the Caribbean and the South American plate causes two major seismologically active fault systems: the roughly west - east trending strike slip fault system along the coast with numerous sub-parallel faults and the Bocono fault system, which dominates the Venezuelan southwest - northeast striking Andes. The main Bocono fault reaches a total length of about 500 km and has a width of approximately 100 km between the southern and northern baseline of the mountain slopes which are marked by inverse faults. This is believed to be due to strain partitioning, a concept which seems to apply as well to the Bocono fault system. The whole fault system is characterized by a high seismicity rate of small scale and intermediate event magnitudes ranging from 1.5 to 6.3 in the last fifty years. In this study we would like to present an investigation on 39 focal mechanism solutions and a b-value mapping of the Andean region with the main goal to throw light on the stess and strain situation. For recompiling the focal memchanisms calculated from first motion polarities, various sources had to been used: seismograms from stations of the local and regional networks of the Seismological Center of ULA, the national seismic network operated by FUNVISIS, the seismic network Lago Maracaibo of PDVSA and the local seismic network of DESURCA. For the b-value mapping we used the two catalogues of ULA and DESURCA of which the last one registered more than 6500 events from 1994 to 1999. The set of focal mechanism solutions studied showed normal, strike slip, and reverse faulting mechanisms concentrated in distinct areas of the Bocono fault system and thus resulting in a zonation also supported by the determinations of the azimuths of the maximum horizontal stress SHmax. This hypothesis of the zonation of the Andes region is strongly supported by the results of the b-value mapping. The zonation as seen in the varying major stress

  7. An overview of Venezuelan gas resources

    SciTech Connect

    Padua, J.A.

    1986-01-01

    This work begins with a historical account starting in 1918 and covers the production and utilization of the country's natural gas, as related to the operations of the Venezuelan oil and petrochemical industries and to the domestic market as a whole. This historical survey concludes with a detailed analysis of the activities conducted in 1985. Next, the estimated reserves of natural gas, both on and offshore is reviewed. This information is then analyzed as to the classification of these reserves, in terms of their probability of existence, their geographic location, and whether they are associated with oil. A forecast of production and demand for the country as a whole, from 1986 to 2005, is presented. This forecast incorporates the most probable scenario for the future of natural gas as an energy resource and raw material, based on the best current criteria. Conclusions are presented indicating that in the long term Venezuelan gas resources will be enough to cover internal and external demand.

  8. Rise of the Andes.

    PubMed

    Garzione, Carmala N; Hoke, Gregory D; Libarkin, Julie C; Withers, Saunia; MacFadden, Bruce; Eiler, John; Ghosh, Prosenjit; Mulch, Andreas

    2008-06-06

    The surface uplift of mountain belts is generally assumed to reflect progressive shortening and crustal thickening, leading to their gradual rise. Recent studies of the Andes indicate that their elevation remained relatively stable for long periods (tens of millions of years), separated by rapid (1 to 4 million years) changes of 1.5 kilometers or more. Periodic punctuated surface uplift of mountain belts probably reflects the rapid removal of unstable, dense lower lithosphere after long-term thickening of the crust and lithospheric mantle.

  9. 9 CFR 113.308 - Encephalomyelitis Vaccine, Venezuelan.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Encephalomyelitis Vaccine, Venezuelan... REQUIREMENTS Live Virus Vaccines § 113.308 Encephalomyelitis Vaccine, Venezuelan. Encephalomyelitis Vaccine... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production....

  10. 9 CFR 113.308 - Encephalomyelitis Vaccine, Venezuelan.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Encephalomyelitis Vaccine, Venezuelan... REQUIREMENTS Live Virus Vaccines § 113.308 Encephalomyelitis Vaccine, Venezuelan. Encephalomyelitis Vaccine... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production....

  11. 9 CFR 113.308 - Encephalomyelitis Vaccine, Venezuelan.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Encephalomyelitis Vaccine, Venezuelan... REQUIREMENTS Live Virus Vaccines § 113.308 Encephalomyelitis Vaccine, Venezuelan. Encephalomyelitis Vaccine... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production....

  12. 9 CFR 113.308 - Encephalomyelitis Vaccine, Venezuelan.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Encephalomyelitis Vaccine, Venezuelan... REQUIREMENTS Live Virus Vaccines § 113.308 Encephalomyelitis Vaccine, Venezuelan. Encephalomyelitis Vaccine... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production....

  13. 9 CFR 113.308 - Encephalomyelitis Vaccine, Venezuelan.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Encephalomyelitis Vaccine, Venezuelan... REQUIREMENTS Live Virus Vaccines § 113.308 Encephalomyelitis Vaccine, Venezuelan. Encephalomyelitis Vaccine... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production....

  14. External coating failures in Venezuelan pipelines

    SciTech Connect

    Rodriguez, V.; Paiva, A.; Castaneda, L.

    1994-12-31

    External organic coatings have been used in Venezuelan pipelines to prevent corrosion in different environments. These environments can be considered critical due to the high temperature of the fluid transported or due to the aggressiveness of the surrounding soils and waters. It has also been found that inadequate application of the coating has contributed greatly to a premature failure. An overview of the techniques used to determine the causes of the failures and the interpretation of the failure analysis will be presented in detail in this paper.

  15. The phlebotomine sandflies of Venezuelan Amazonia.

    PubMed

    Feliciangeli, M D; Ramirez Perez, J; Ramirez, A

    1988-01-01

    Phlebotomine sandflies were surveyed in two ecologically contrasted areas, the northern moist and southern wet tropical forests, of the Territorio Federal Amazonas, Venezuela. Three new taxa and twenty-one new records were added to the previously known species list for Venezuelan sandflies, which now totals eighty species. Both sexes of Lutzomyia (Psychodopygus) killicki sp.n., L. (Trichophoryomyia) bettinii sp.n., L. (Nyssomyia) olmeca reducta subsp.n. and and the females of L. bernalei Osorno et al., Brumptomyia pintoi Costa Lima and L. begonae (Ortiz & Torres) are described and illustrated.

  16. Bacteria recovered from a high-altitude, tropical glacier in Venezuelan Andes.

    PubMed

    Ball, María M; Gómez, Wileidy; Magallanes, Xavier; Rosales, Rita; Melfo, Alejandra; Yarzábal, Luis Andrés

    2014-03-01

    Glacial-ice microorganisms are intensively studied world-wide for a number of reasons, including their psychrophilic lifestyle, their usefulness in biotechnology procedures and their relationship with the search of life outside our planet. However, because of the difficulties for accessing and working at altitudes of >5.000 m above sea level, tropical glaciers have received much less attention than their arctic and antarctic counterparts. In the present work we isolated and characterized a total of forty-five pure isolates originating from direct plating of melted ice collected at the base of a rapidly-retreating, small glacier located at around 4.900 m.a.s.l. in Mount Humboldt (Sierra Nevada National Park, Mérida State, Venezuela). Initial examination of melted ice showed the presence of abundant- (>10⁶ cells ml⁻¹), morphologically diverse- and active bacterial cells, many of which were very small ("dwarf cells"). The majority of the isolates were psychrophilic or psychrotolerant and many produced and excreted cold-active extracellular enzymes (proteases and amylases). The antibiotic tests showed an elevated percentage of isolates resistant to high doses (100 μg/ml) of different antibiotics including ampicillin, penicillin, nalidixic acid, streptomycin, chloramphenicol, kanamycin and tetracycline. Multiresistance was also observed, with 22.22 % of the strains simultaneously resistant up to five of the antibiotics tested. Metal resistance against Ni⁺⁺, Zn⁺⁺ and Cu⁺⁺ was also detected. In accordance with these results, plasmids of low and high molecular weight were detected in 47 % of the isolates. Twenty-two partial 16S rDNA sequences analyzed allowed grouping the isolates within five different phyla/classes: Alpha-, Beta- and Gamma-proteobacteria, Actinobacteria and Flavobacteria. This is the first report concerning South American Andean glacial ice microorganisms.

  17. Experimental Study of Soil Organic Matter Loss From Cultivated Field Plots In The Venezuelan Andes.

    NASA Astrophysics Data System (ADS)

    Bellanger, B.; Huon, S.; Velasquez, F.; Vallès, V.; Girardin A, C.; Mariotti, A. B.

    The question of discriminating sources of organic matter in suspended particles of stream flows can be addressed by using total organic carbon (TOC) concentration and stable isotope (13C, 15N) measurements when constant fluxes of organic matter supply can be assumed. However, little is known on the dynamics of organic matter release during soil erosion and on the temporal stability of its isotopic signature. In this study, we have monitored soil organic carbon loss and water runoff using natural rainfall events on three experimental field plots with different vegetation cover (bare soil, maize and coffee fields), set up on natural slopes of a tropical mountainous watershed in NW Venezuela (09°13'32'' ­ 09°10'00''N, 70°13'49'' ­ 70°18'34''W). Runoff and soil loss are markedly superior for the bare field plot than for the coffee field plot: by a factor 15 ­ 36, respectively, for the five-month experiment, and by a factor 30 ­ 120, respectively, during a single rainfall event experiment. Since runoff and soil organic matter loss are closely linked during most of the flow (at the time scales of this study), TOC concentration in suspended matter is constant. Furthermore, stable isotope compositions reflect those of top-soil organic matter from which they originate.

  18. Chemical composition and larvicidal activity of Eugenia triquetra essential oil from Venezuelan Andes.

    PubMed

    Mora, Flor D; Avila, Jorge L; Rojas, Luis B; Ramírez, Rosslyn; Usubillaga, Alfredo; Segnini, Samuel; Carmona, Juan; Silva, Bladimiro

    2010-06-01

    The chemical constituents of the essential oil obtained by hydrodistillation of the leaves of Eugenia triquetra O. Berg, collected in Táchira State, Venezuela, were identified by GC-MS analysis. Twenty-six components, which made up 88.5% of the oil, were identified. The major constituents were linalool (17.5%), limonene (16.9%), alpha-pinene (11.6%), beta-pinene (8.7%), and p-cymene (3.7%). The essential oil was tested against third-instar larvae of Aedes aegypti, showing a LC50 value of 64.8 +/- 5.6 ppm.

  19. Alphaviral equine encephalomyelitis (Eastern, Western and Venezuelan).

    PubMed

    Aréchiga-Ceballos, N; Aguilar-Setién, A

    2015-08-01

    Summary Alphaviral equine encephalomyelitis is a mosquito-borne infection that causes severe neurological disease and fatalities in horses and humans in the Americas. Consequently, the equine alphaviruses (Eastern, Western and Venezuelan) are of considerable concern worldwide and are notifiable to the World Organisation for Animal Health. In addition, these diseases are considered a potent potential biological weapon, emphasising the need to develop an effective vaccine. Alphaviral equine encephalomyelitis is caused by Eastern equine encephalomyelitis virus (EEEV), Western equine encephalomyelitis virus (WEEV) or Venezuelan equine encephalomyelitis virus (VEEV), which are related members of the Alphavirus genus in the Togaviridae family. Although related, the three viruses are genetically and antigenically distinct. The disease is characterised by fever, anorexia, depression and clinical signs of encephalomyelitis, and may be fatal in up to 90% of cases, for both humans and horses, particularly in the case of EEE. Surviving horses develop lifelong immunity but may have permanent neuropathology. The aim of this paper is to analyse the scientific information available on the evolution of EEE, WEE and VEE, and any potential vaccines.

  20. Naval Ships Acquisition Strategy for the Venezuelan Navy.

    DTIC Science & Technology

    1982-06-01

    strategy is formulated from a management point ov view, based on two models, to improve the eyisting Venezuelan Navy acquisition process--Model "A- to...formulated from a management point of view, based on two models, to improve the existing Venezuelan Navy acquisition process-- Model "A" to the pro...the accom- plishment of the institutional, social and economic goals of the country. This novel process is based on planning, pro- gramming and

  1. Development of a Genetically Engineered Venezuelan Equine Encephalitis Virus Vaccine

    DTIC Science & Technology

    1988-12-20

    immunization, the horses will be returned to the large animal biocontainment facility to be challenged with equine virulent VEE virus. The animals will be...AD £IT FiLE C p DEVELOPMENT OF A GENETICALLY ENGINEERED VENEZUELAN EQUINE ENCEPHALITIS VIRUS VACCINE ANNUAL REPORT to DENNIS W. TRENT 0DECEMBER 20...Engineered Venezuelan Equine Encephalitis Virus Vaccine 12. PERSONAL AUTHOR(S) Dennis W. Trent 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT

  2. Genetic diversity of Venezuelan alphaviruses and circulation of a Venezuelan equine encephalitis virus subtype IAB strain during an interepizootic period.

    PubMed

    Medina, Gladys; Garzaro, Domingo J; Barrios, Miguel; Auguste, Albert J; Weaver, Scott C; Pujol, Flor H

    2015-07-01

    Several species of alphaviruses have been previously described in the Americas, some of which are associated with encephalitis and others are associated with arthralgia. Venezuelan equine encephalitis virus (VEEV) and eastern equine encephalitis virus (EEEV) are endemic to Venezuela, with the former being responsible for major outbreaks of severe and often fatal disease in animals and humans. The aim of this study was to analyze the genetic diversity of Venezuelan alphaviruses isolated during two decades (1973-1999) of surveillance in northern Venezuela. Phylogenetic analysis indicated the circulation of a VEEV subtype IAB strain 8 years after the last reported outbreak. Thirteen strains within two subclades of South American lineage III of EEEV were also found in Venezuela. Considerable genetic variability was observed among Venezuelan Una virus strains, which were widely distributed among the clades. The first Venezuelan Mayaro sequence was also characterized.

  3. Genetic Diversity of Venezuelan Alphaviruses and Circulation of a Venezuelan Equine Encephalitis Virus Subtype IAB Strain During an Interepizootic Period

    PubMed Central

    Medina, Gladys; Garzaro, Domingo J.; Barrios, Miguel; Auguste, Albert J.; Weaver, Scott C.; Pujol, Flor H.

    2015-01-01

    Several species of alphaviruses have been previously described in the Americas, some of which are associated with encephalitis and others are associated with arthralgia. Venezuelan equine encephalitis virus (VEEV) and eastern equine encephalitis virus (EEEV) are endemic to Venezuela, with the former being responsible for major outbreaks of severe and often fatal disease in animals and humans. The aim of this study was to analyze the genetic diversity of Venezuelan alphaviruses isolated during two decades (1973–1999) of surveillance in northern Venezuela. Phylogenetic analysis indicated the circulation of a VEEV subtype IAB strain 8 years after the last reported outbreak. Thirteen strains within two subclades of South American lineage III of EEEV were also found in Venezuela. Considerable genetic variability was observed among Venezuelan Una virus strains, which were widely distributed among the clades. The first Venezuelan Mayaro sequence was also characterized. PMID:25940191

  4. Venezuelan Equine Encephalitis Virus, Southern Mexico

    PubMed Central

    Estrada-Franco, José G.; Navarro-Lopez, Roberto; Freier, Jerome E.; Cordova, Dionicio; Clements, Tamara; Moncayo, Abelardo; Kang, Wenli; Gomez-Hernandez, Carlos; Rodriguez-Dominguez, Gabriela; Ludwig, George V.

    2004-01-01

    Equine epizootics of Venezuelan equine encephalitis (VEE) occurred in the southern Mexican states of Chiapas in 1993 and Oaxaca in 1996. To assess the impact of continuing circulation of VEE virus (VEEV) on human and animal populations, serologic and viral isolation studies were conducted in 2000 to 2001 in Chiapas State. Human serosurveys and risk analyses indicated that long-term endemic transmission of VEEV occurred among villages with seroprevalence levels of 18% to 75% and that medical personnel had a high risk for VEEV exposure. Seroprevalence in wild animals suggested cotton rats as possible reservoir hosts in the region. Virus isolations from sentinel animals and genetic characterizations of these strains indicated continuing circulation of a subtype IE genotype, which was isolated from equines during the recent VEE outbreaks. These data indicate long-term enzootic and endemic VEEV circulation in the region and continued risk for disease in equines and humans. PMID:15663847

  5. Charles Darwin in the Andes

    ERIC Educational Resources Information Center

    Bizzo, Nelio; Bizzo, Luis Eduardo Maestrelli

    2006-01-01

    Considering geological time as an important epistemological obstacle to the construction of ideas on biological evolution, a study was carried out on the so-called "Darwin Papers". The conclusion was that Charles Darwin's excursion in the Andes during March-April 1835 was a crucial step in this regard. An expedition was carried out in…

  6. Characterization of Venezuelan heavy oil vacuum residua

    SciTech Connect

    Izquierdo, A.; Carbognani, L.; Leon, V.; Parisi, A. )

    1988-06-01

    Characterization of abundant ''heavy'' feedstocks such as tar sands, heavy oils and vacuum residua will play a fundamental role in the use of these energy sources. Their physical and chemical properties vary from one feed to another, and this can have some consequences in their necessary upgrading processes. In this paper results on the characterization of 510/sup 0/C-vacuum residua (VR) obtained from Venezuelan Heavy and Medium Oils are presented. These are Morichal (Mo), Merey (Me), Guafita (Gu) and Barinas (Ba). The VR have all an API gravity between 3 and 6, more than 15% asphaltenes, metals above 200 ppm, as well as high contents of nitrogen, more than 6000 ppm, and sulphur, over 1%. It has been found that when these feeds are hydrotreated under similar conditions the processability improves in the order Ba

  7. Tectonics of the central Andes

    NASA Technical Reports Server (NTRS)

    Bloom, Arthur L.; Isacks, Bryan L.; Fielding, Eric J.; Fox, Andrew N.; Gubbels, Timothy L.

    1989-01-01

    Acquisition of nearly complete coverage of Thematic Mapper data for the central Andes between about 15 to 34 degrees S has stimulated a comprehensive and unprecedented study of the interaction of tectonics and climate in a young and actively developing major continental mountain belt. The current state of the synoptic mapping of key physiographic, tectonic, and climatic indicators of the dynamics of the mountain/climate system are briefly reviewed.

  8. Development of a Genetically Engineered Venezuelan Equine Encephalitis Virus Vaccine

    DTIC Science & Technology

    1991-04-15

    antibody neutralization titers of sera from the TC-5A immunized horses ranged from 64 to > 128; however, the sera did not neutralize the equine virulent VEE...human adenovirus 5 DNA. Virology 52:456-467. Groot, H. 1972. The health and economic impact of Venezuelan equine encephalitis (VEE). p. 7-16. In... equine encephalitis (VEE). p. 7-16. In Venezuelan Encephalitis, Sci. Pub. 243, Pan American Health Organization, Washington, D.C. Hunt, A.R., Johnson, A.J

  9. Jotï ecogony, Venezuelan Amazon

    NASA Astrophysics Data System (ADS)

    Zent, Egleé L.

    2013-03-01

    The current environmental crisis permeates the discourse and concerns of people all over the world. Consideration of diverse environmental ethics showing the alternative ways in which people conceptualize and relate to nature and natural resources are critical for bringing about more sustainable human behaviors. After a brief review of Western historical notions of nature, this work explores the ecogony, or causal reasons, that trigger the behavior of the Jotï, an Amerindian people of the Venezuelan Amazon, with other entities and the forest that they inhabit. The analysis presented synthesizes 15 years of transdisciplinary ethno-ecological research comprising quantitative and qualitative methods (collection of herbarium voucher specimens, floristic inventories in forest plots, structured interviews focused on plot vegetation, semi-structured interviews of life-histories, participant observation, time allocation studies, food resource accounting, focal person following observations, garden crop inventories and censuses, mapping of wild resource harvest locations, among others). Jotï pragmatic and ideological tenets generate a distinctive environmental ethics based on ecogonic nodes. Notions of interdependence, humanity and person are articulated on a daily basis through several dynamics: (1) hyper-awareness of all living things’ dependence on each other and other elements of the biophysical environment at macroscales and microscales, (2) the construction of human spiritual, conscious, physical and agentive constituents from a variety of diverse botanical and zoological species and mineral components of their homeland, and (3) an understanding of the aggregate surroundings, including a significant portion of the biotic and abiotic components, as potential subjects with awareness, creativity and moral stances. This condition of interdependence confers rights and duties on all the parts. Jotï horizontal communications with and among life-forms sustain their

  10. Transcultural Diabetes Nutrition Algorithm (tDNA): Venezuelan Application

    PubMed Central

    Nieto-Martínez, Ramfis; Hamdy, Osama; Marante, Daniel; Inés Marulanda, María; Marchetti, Albert; Hegazi, Refaat A.; Mechanick, Jeffrey I.

    2014-01-01

    Medical nutrition therapy (MNT) is a necessary component of comprehensive type 2 diabetes (T2D) management, but optimal outcomes require culturally-sensitive implementation. Accordingly, international experts created an evidence-based transcultural diabetes nutrition algorithm (tDNA) to improve understanding of MNT and to foster portability of current guidelines to various dysglycemic populations worldwide. This report details the development of tDNA-Venezuelan via analysis of region-specific cardiovascular disease (CVD) risk factors, lifestyles, anthropometrics, and resultant tDNA algorithmic modifications. Specific recommendations include: screening for prediabetes (for biochemical monitoring and lifestyle counseling); detecting obesity using Latin American cutoffs for waist circumference and Venezuelan cutoffs for BMI; prescribing MNT to people with prediabetes, T2D, or high CVD risk; specifying control goals in prediabetes and T2D; and describing regional differences in prevalence of CVD risk and lifestyle. Venezuelan deliberations involved evaluating typical food-based eating patterns, correcting improper dietary habits through adaptation of the Mediterranean diet with local foods, developing local recommendations for physical activity, avoiding stigmatizing obesity as a cosmetic problem, avoiding misuse of insulin and metformin, circumscribing bariatric surgery to appropriate indications, and using integrated health service networks to implement tDNA. Finally, further research, national surveys, and validation protocols focusing on CVD risk reduction in Venezuelan populations are necessary. PMID:24699193

  11. Transcultural diabetes nutrition algorithm (tDNA): Venezuelan application.

    PubMed

    Nieto-Martínez, Ramfis; Hamdy, Osama; Marante, Daniel; Marulanda, María Inés; Marchetti, Albert; Hegazi, Refaat A; Mechanick, Jeffrey I

    2014-04-02

    Medical nutrition therapy (MNT) is a necessary component of comprehensive type 2 diabetes (T2D) management, but optimal outcomes require culturally-sensitive implementation. Accordingly, international experts created an evidence-based transcultural diabetes nutrition algorithm (tDNA) to improve understanding of MNT and to foster portability of current guidelines to various dysglycemic populations worldwide. This report details the development of tDNA-Venezuelan via analysis of region-specific cardiovascular disease (CVD) risk factors, lifestyles, anthropometrics, and resultant tDNA algorithmic modifications. Specific recommendations include: screening for prediabetes (for biochemical monitoring and lifestyle counseling); detecting obesity using Latin American cutoffs for waist circumference and Venezuelan cutoffs for BMI; prescribing MNT to people with prediabetes, T2D, or high CVD risk; specifying control goals in prediabetes and T2D; and describing regional differences in prevalence of CVD risk and lifestyle. Venezuelan deliberations involved evaluating typical food-based eating patterns, correcting improper dietary habits through adaptation of the Mediterranean diet with local foods, developing local recommendations for physical activity, avoiding stigmatizing obesity as a cosmetic problem, avoiding misuse of insulin and metformin, circumscribing bariatric surgery to appropriate indications, and using integrated health service networks to implement tDNA. Finally, further research, national surveys, and validation protocols focusing on CVD risk reduction in Venezuelan populations are necessary.

  12. Brokerage, Political Opportunity, and Protest in Venezuelan Higher Education Reform

    ERIC Educational Resources Information Center

    Storm, Elliot

    2015-01-01

    This paper explores two episodes of contention in the ongoing conflict between the Venezuelan government and the country's autonomous universities. In August 2009, Venezuela's National Assembly approved and implemented the controversial Organic Education Law. Sixteen months later, the Assembly approved the similarly polarizing Law of University…

  13. Molecular systematics of the neotropical scorpion genus Tityus (Buthidae): the historical biogeography and venom antigenic diversity of toxic Venezuelan species.

    PubMed

    Borges, Adolfo; Bermingham, Eldredge; Herrera, Nimiadina; Alfonzo, Marcelo J; Sanjur, Oris I

    2010-01-01

    We provide a mitochondrial DNA-based phylogenetic hypothesis for 21 Tityus species collected in Venezuela, Trinidad, Brazil and Panama, including 12 taxa known to be toxic to humans. Our phylogenetic reconstruction is based on 850 nucleotides of the combined cytochrome oxidase subunit I and 16S rRNA genes for most species, and centered on Venezuelan scorpions owing to the detailed taxonomic and biogeographic information available for Tityus in this region. The principal phylogenetic result was the strong support for mtDNA clades representing geographical groupings associated with the Perijá mountain range, the Mérida Andes, or the central and eastern coastal ranges in Venezuela, suggesting that vicariance has been a potent force in the diversification of local scorpions. Venezuelan Tityus species have been organized by González-Sponga into three artificial morphological groups, "androcottoides", "discrepans", and "nematochirus", based on the array of ventral carinae in metasomal segments II-IV. We also incorporated a fourth morphological group ("Tityus clathratus"), recently documented in Venezuela. Our results do not support the clustering of the species in the "androcottoides" and "discrepans" morphological groups, which include the majority of taxa of medical importance, but provided support for the "nematochirus" species group. T. clathratus was found to cluster with the Brazilian T. serrulatus and T. bahiensis. Divergence times of most clades are consistent with major events in the geological history of northern Venezuela and suggest that many Venezuelan Tityus species formed in the late Miocene and the Pliocene. In turn, we used the Tityus mtDNA phylogeny to determine the potential utility of phylogenetic systematics to predict Tityus venom antigenic reactivity by testing the recognition of T. nororientalis, T. discrepans, T. zulianus, T. perijanensis, and T. clathratus venoms by anti-T. discrepans horse antibodies. Cross-reactivity was significantly

  14. Western Slope of Andes, Peru

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Along the western flank of the Andes, 400 km SE of Lima Peru, erosion has carved the mountain slopes into long, narrow serpentine ridges. The gently-sloping sediments have been turned into a plate of worms wiggling their way downhill to the ocean.

    The image was acquired September 28, 2004, covers an area of 38 x 31.6 km, and is located near 14.7 degrees south latitude, 74.5 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  15. Molecular Strategy for the Construction of a Genetically Engineered Vaccine for Venezuelan Equine Encephalitis Virus

    DTIC Science & Technology

    1991-03-29

    AD-A236 920 MOLECULAR STRATEGY FOR THE CONSTRUCTION OF A GENETICALLY ENGINEERED VACCINE FOR VENEZUELAN EQUINE ENCEPHALITIS VIRUS FINAL REPORT ROBERT...89-C-9089 engineered vaccine for Venezuelan Equine Encephalitis Virus 62787A 3M162787A871 AD Robert Edward Johnston WUDA318408 Nancy Lee Davis...multiple mutants were more attenuated than those containing a single attenuating Venezuelan equine encephalitis virus (VEE) full-length clones; In vitro

  16. VIRUS-SPECIFIC POLYSOMES IN CELLS INFECTED WITH THE VENEZUELAN EQUINE ENCEPHALOMYELITIS VIRUS,

    DTIC Science & Technology

    VENEZUELAN EQUINE ENCEPHALOMYELITIS VIRUS, *RIBOSOMES, *TISSUE CULTURE CELLS, RIBOSOMES, GROWTH(PHYSIOLOGY), INFECTIOUS DISEASES, ARBOVIRUSES, VIRUSES, NUCLEIC ACIDS, BIOSYNTHESIS, USSR, MOLECULAR STRUCTURE.

  17. Grenvillian remnants in the Northern Andes: Rodinian and Phanerozoic paleogeographic perspectives

    NASA Astrophysics Data System (ADS)

    Cardona, A.; Chew, D.; Valencia, V. A.; Bayona, G.; Mišković, A.; Ibañez-Mejía, M.

    2010-01-01

    Grenvillian crust is encountered in several basement inliers in the northern Andes of Colombia, Ecuador and Peru and is also represented as a major detrital or inherited component within Neoproterozoic to Paleozoic sedimentary and magmatic rocks. This review of the tectonic and geochronological record of the Grenvillian belt in the northern Andes suggests that these crustal segments probably formed on an active continental margin in which associated arc and back-arc magmatism evolved from ca. 1.25 to 1.16 Ga, possibly extending to as young as 1.08 Ga. The lithostratigraphic and tectonic history of the Grenvillian belt in the northern Andes differs from that of the Sunsas belt on the southwest Amazonian Craton and from the Grenvillian belt of Eastern Laurentia. It is considered that this belt, along with similar terranes of Grenvillian age in Middle America and Mexico define a separate composite orogen which formed on the northwestern margin of the Amazonian Craton. Microcontinent accretion and interaction with the Sveconorwegian province on Baltica is a feasible tectonic scenario, in line with recent paleogeographic reconstructions of the Rodinian supercontinent. Although Phanerozoic tectonics may have redistributed some of these terranes, they are still viewed as para-autocthonous domains that remained in proximity to the margin of Amazonia. Paleogeographic data derived from Phanerozoic rocks suggest that some of the Colombian Grenvillian fragments were connected to northernmost Peru and Ecuador until the Mesozoic, whereas the Mexican terranes where attached to the Colombian margin until Pangea fragmentation in Late Triassic times.

  18. Andes

    Atmospheric Science Data Center

    2013-04-18

    ... provide a striking demonstration of the power of water erosion. This image pair was acquired by the Multi-angle Imaging ... with the red filter placed over your left eye. Two main erosion formations can be seen. The one above image center is carved by the Rio ...

  19. Socialized medicine or state-ruled medicine: the Venezuelan dilemma.

    PubMed

    Morgado, P J

    1989-07-01

    The economic crisis in which Venezuela is living, caused by the fall in oil prices, has forced the government to reorganize its medical services. A central administrative organ, the National Health Service, has been created. It seeks to develop a social medicine directed at the less favored classes of the population. Notwithstanding the continuously rising costs of private medicine, which, until now, the government has permitted without restrictions, the shadow of government intervention looms ominously over private practice, where subemployment of doctors already exists, along with the growing tendencies of insurance companies to impose economic conditions. The Venezuelan Medical Federation, which, by law, groups all Venezuelan doctors, has began a battle on two main fronts: against the State intervention and against the insurance companies who hope to benefit at the expense of the already underpaid doctors.

  20. Problem solving workshop for physics teachers at Venezuelan High School

    NASA Astrophysics Data System (ADS)

    Andrés, Maria Maite

    1997-03-01

    The Venezuelan Physics Olympiad is aimed at high school students. The syllabus at the high school level includes mechanics, electricity and magnetism, vibrations and waves, optics, fluid statics, and energy and its transformations. The Venezuelan Physics Olympiad consists of three tests. The preliminary test has 20 problems. They are multiple choice questions with a choice of five options. The theory test has 8 or 10 open-ended problems and the experimental final test is a problem whose solution it is made at the laboratory. The results of the five Venezuelan Physics Olympiads, 1991-1995, were analyzed. It was found that students solve physics problems the same way they solve mathematics exercises (1, 2). They emphasized the mathematical processes too much and paid little attention to description and analysis of the physical situation involved. Also, we observed that students did not develop experimental skills at school and their experience with laboratory work is very poor. According to these results, we designed two workshops for in-service physics teachers. One workshop focuses on solving pencil-and-paper-type problems, and the other one provides knowledge and skills about experimental work. Both workshops are designed with a cognitive approach (3-7).

  1. [Isolation of Helicobacter pylori in gastric mucosa, dental plaque and saliva in a population from the Venezuelan Andes].

    PubMed

    De Sousa, Lilibeth; Vásquez, Libia; Velasco, Judith; Parlapiano, Donatella

    2006-06-01

    Helicobacter pylori infection is common in people. However, the existence of extra gastric reservoirs and transmission routes remain controversial in the field. Because the oral cavity has been proposed as a reservoir for H. pylori, a study was carried out to determine the presence of H. pylori in dental plaque and saliva. The results were asociated with those obtained in the gastric biopsy. Ninety-seven dyspeptic and fifty asymptomatic patients were studied and samples taken for biopsy, dental plaque and saliva. The gastric biopsies were evaluated using microbiology and histology methods. Cultures and urease tests were carried out on the oral cavity samples and included pretreatment methods using urea and HCl. The frequency of H. pylori for all the patients evaluated was 75.5%. H. pylori was not isolated in saliva or dental plaque in any of the two groups studied with or without sample pretreatment. The urease test in dental plaque was positive in 99.3% of the patients and 89.8% in saliva. There was no statistically significant difference between the infection prevalence by H. pylori in dyspeptic or not dyspeptic patients. The obtained results suggest that the methodology used for the detection of H. pylori is not sufficiently sensitive for the determination of the microorganism in the oral cavity.

  2. By analogy with late paleozoic orogeny in the Venezuelan Andes, Maracaibo Basin is en route to a granitic event

    SciTech Connect

    Shagam, R.; Giegengack, R.F.; Lutz, T.M.

    1985-01-01

    Postulated stages of orogeny in a continental crustal setting are:- 1. Stresses of plate convergence lead to block uplift and complementary basin subsidence. The basin fills with 12-14 km of illite-rich flysch (1km/3Ma). This about doubles the thickness of K-rich sial. 2. In situ heating of the flysch by radioactive decay provides a thermal gradient of c.35/sup 0/C/km and it is metamorphosed (pre-deformation) to greenschists facies. 3. After maximum crustal subsidence continued compression results in updoming of crust and overlying flysch. Cannibalism of flysch, cooling and mild subsidence follow; autometamorphism declines. 4. Thin deltaic-marine deposits complete basin fill over the meta-flysch. The unconformity (a span of only 5-10 Ma) is of minor import. 5. Resetting of the thermal profile of the depressed crust lags far behind that in the flysch. Parallels to the above in the Maracalbo basin fill are: -thickness (approx.11km), nature (flysch abounds), rate of deposition (c.1km/3-4Ma), thermal gradient (c.33/sup 0/C/km) and overall tesselar shape. Presence of impermeable strata in the Maracaibo Basin suggests that large-scale fluid convection is inhibited; conductive models of heat transfer can be used. Computer modeling suggests that radiogenic heat, augmented by exothermic oxidation of organic matter, and with a normal mantle heat flow will explain the autometamorphism of the flysch. Alternative orogenic models invoking pull-apart basins do not explain the great thickness of sediments and absence of volcanic activity.

  3. Dynamics, Patterns and Causes of Fires in Northwestern Amazonia

    PubMed Central

    Armenteras, Dolors; Retana, Javier

    2012-01-01

    According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests. PMID:22523580

  4. Dynamics, patterns and causes of fires in Northwestern Amazonia.

    PubMed

    Armenteras, Dolors; Retana, Javier

    2012-01-01

    According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests.

  5. Thermochronology and tectonics of the Mérida Andes and the Santander Massif, NW South America

    NASA Astrophysics Data System (ADS)

    van der Lelij, Roelant; Spikings, Richard; Mora, Andrés

    2016-04-01

    New apatite U-Pb and multiphase 40Ar/39Ar data constrain the high to medium temperature (~ 500 °C-~ 300 °C) thermal histories of igneous and metamorphic rocks exposed in the Mérida Andes of Venezuela, and new apatite and zircon fission track data constrain the ~ 500 °C-~ 60 °C thermal histories of pre-Jurassic igneous and metamorphic rocks of the adjacent Santander Massif of Colombia. Computed thermal history envelopes using apatite U-Pb dates and grain size information from an Early Palaeozoic granodiorite in the Mérida Andes suggest that it cooled from > 500 °C to < 350 °C between ~ 266 Ma and ~ 225 Ma. Late Permian to Triassic cooling is also recorded in Early Palaeozoic granitoids and metasedimentary rocks in the Mérida Andes by numerous new muscovite and biotite 40Ar/39Ar plateau dates spanning 257.1 ± 1.0 Ma to 205.1 ± 0.8 Ma. This episode of cooling is not recognised in the Santander Massif, where 40Ar/39Ar data suggest that some Early Palaeozoic rocks cooled below ~ 320 °C in the Early Palaeozoic. However, most data from pre-Jurassic rocks reveal a regional heat pulse at ~ 200 Ma during the intrusion of numerous shallow granitoids, resulting in temperatures in excess of ~ 520 °C, obscuring late Palaeozoic histories. The generally accepted timing of amalgamation of Pangaea along the Ouachita-Marathon suture pre-dates Late Permian to Triassic cooling recorded in basement rocks of the Mérida Andes by > 30 Ma, and its effect on rocks preserved in north-western South America is unknown. We interpret late Permian to Triassic cooling in the Mérida Andes to be driven by exhumation. Previous studies have suggested that a short phase of shortening and anatexis is recorded at ~ 253 Ma in the Maya Block, which may have been adjacent to the basement rocks of the Mérida Andes in the Late Permian. The coeval onset of exhumation in the Mérida Andes may be a result of increased coupling in the magmatic arc, which was located along the western margin of

  6. Experimental Venezuelan Equine Encephalomyelitis Virus Infection of the Bovine

    PubMed Central

    Walton, Thomas E.; Johnson, Karl M.

    1972-01-01

    Two groups of four dairy cows (Bos taurus) were infected subcutaneously with the epizootic Venezuelan equine encephalomyelitis virus (VEE) strains MF-8 and San Pelayo, respectively. Animals experienced no clinical illness, but all developed significant neutropenia. Virus was recovered once each from the blood of three animals but did not exceed 102.2 SMICLD50 (Suckling mouse intracerebral lethal dose50)/ml. Specific neutralizing antibodies appeared in the serum of all animals, but there were no significant differences in titers against different naturally occurring VEE subtypes. Dairy cattle thus appear to play no role in virus transmission during VEE epizootics but may serve as retrospective immunological sentinels of virus activity. PMID:4564396

  7. Outbreak of vampire bat biting in a Venezuelan village.

    PubMed

    Caraballo, A J

    1996-10-01

    An outbreak of 154 cases of vampire bat biting in a four-month period in the gold mine of Payapal, a Venezuelan village, is reported. All patients were bitten during the night and the most bites were on their toes. No complication attributed to the bite was reported. Diagnoses of rabies virus made by means of immunofluorescence were negative. A possible reason for this outbreak may been the development of mining areas, with the inhabitants providing an alternative food source for the bats.

  8. [Reference values of fats for the Venezuelan population].

    PubMed

    Giacopini de Z, María; Alonso Villamizar, Hilda; Ruiz, Nelina; Abrahams Ocanto; Martínez, Benailim; Bosch, Virgilio

    2013-12-01

    The present work is a review of the available intormation in the scientific literature in food and human nutrition related to fats and oils, in order to bring a range of guidance on nutritional requirements in pregnancy, infancy, childhood and adulthood, in improving the health and nutritional well-being. Topics include: Characteristics of fatty acids, nomenclature, requirements and recommendations regarding their consumption and its impact on the health situation in Venezuela and recommendations. We present recommendations for total fat requirements and the different fatty acids for different age groups and biological conditions. It was noted that depending on the distribution of fat intake by food of the Venezuelan population energy intake (28.84%) is in line with the recommendations of the FAO/WHO, 2010. Vegetable fats contribute about 62.60% of the total fat where the main source are oils (83.97%) followed by cereals (21.47%) the rest is contributed by vegetables, legumes, vegetables and others. While animal fats represent a 36.84%. Total chiffon, where milk and dairy products account for the highest percentage (47.43%) followed by meat and fish (41.07%), and a lower contribution from eggs (2.07%). This suggests a high ratio n-6/n-3 in feeding conditions Venezuelan general, being necessary to consider ways in which diminish this relationship, in order to prevent cardiovascular disease.

  9. Civilian control of professionalizing militaries: implications of the Venezuelan case

    SciTech Connect

    Anderson, R.B.

    1985-01-01

    Highly professionalized militaries whose focus is internal security and national development have been shown to be prone to active, directive involvement in politics. In Latin America, this phenomenon has been most notably evident in Brazil since 1964 and Peru between 1968 and 1980. The Venezuelan military offers a case of a more moderately professionalized military which was exposed to the widely disseminated internal security doctrine of the 1960s but, on the surface, exhibited declining levels of militarism. This study examines the varying levels of civilian control in Venezuela between 1945 and 1979 in the context of increasing military professionalization, and seeks to clarify the theoretical relationship between the two variables by using a unique, if not deviant, case. After developing a theoretical definition of the general concept of control, the study derives a definition of civilian control which employs civilian and military behavior, civilian and military attitudes, and military motivations. Application of this definition to the Venezuelan case indicates that civilian control has been more tenuous than more superficial observation would indicate. The study shows that increases in professionalization led to strains on the consolidation of civilian control, while also showing that limits on the level and content of professionalization enabled Venezuela to avoid authoritarian consequences.

  10. Characterising the Venezuelan Troposphere for Radio-Astronomy Studies

    NASA Astrophysics Data System (ADS)

    Pacheco, R.; Muñoz, A. G.; Brito, A.; Cubillán, N.

    2009-05-01

    Venezuela possesses a very useful geographical location for doing Radioastronomy. Recently, the Venezuelan Government (via FIDETEL-Ministerio de Ciencia y Tecnología) has aproved to the Laboratorio de Astronomía y Física Teórica (LAFT) of La Universidad del Zulia (Venezuela) the adquisition of four 3 meter diameter parabolic dishes that will be set as a radio-interferometer receiver and that can be used for certain Radioastronomy purposes. The specifications of the instrument will be treated elsewhere (Muñoz and Hernández 2007). To this aim, as ussually, the first step is to characterize the losses due to the atmosphere, and their evolution over time. In previous works (Muñoz et al. 2004, Memoires of V RIAO/VIII OPTILAS, M10-5 Modelling Tropospheric Radio-Attenuation Parameters for Venezuela, 359; Muñoz et al. 2006, CIENCIA, Vol. 14, 4, 428) we have studied some relevant electromagnetic (e-m) attenuation parameters dueto hydrometeors and absortion gases in the lower atmosphere, focused in local telecommunication applications (surface e-m trajectories). In this work we extend our results to include the cenital and quasi-cenital e-m trajectories, characterizing thus the medium losses in the 0.4-4.0 GHz spectral window for several Venezuelan locations. We report refractivity values and their gradients, tropospheric indexes, extinction coefficients and the total rain attenuation for the whole territory under study.

  11. Astrometric Positioning of the Venezuelan Satellite VeneSat-1 "PASAVEN"

    NASA Astrophysics Data System (ADS)

    Otero, S.; Abad, C.; Hernández, R.

    2014-06-01

    By means of this document we inform regarding the collaboration between the Venezuelan institutions, Bolivarian Agency for Space Activities (ABAE) and the Astronomy Research Center (CIDA) with the purpose of using astrometry for the tracking of the Venezuelan Geostationary Satellite Venesat1 by means of optical observation. For this purpose two small astronomical observatories shall be installed on the space tracking ground stations owned by the ABAE in Venezuela and we hope that in a short term they shall be producing the expected results, and also that these observations may be extended to future Venezuelan satellites and to the determination of the geostationary space debris trajectories.

  12. Earth - False Color Mosaic of the Andes

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This false-color mosaic of the central part of the Andes mountains of South America (70 degrees west longitude, 19 degrees south latitude) is made up of 42 images acquired by the Galileo spacecraft from an altitude of about 25,000 kilometers (15,000 miles). A combination of visible (green) and near-infrared (0.76 and 1.0-micron) filters was chosen for this view to separate regions with distinct vegetation and soil types. The mosaic shows the area where Chile, Peru and Bolivia meet. The Pacific Coast appears at the left of the image-- Galileo captured this view as it traveled west over the Pacific Ocean, looking back at the Andes. Lakes Titicaca and Poopo are nearly black patches at the top and center, respectively; a large light-blue area below and to the left of Lake Poopo is Salar de Uyuni, a dry salt lake some 120 kilometers (75 miles) across. These lakes lie in the Altiplano, a region between the western and eastern Andes, which are covered by clouds. The vegetation-bearing Gran Chaco plains east of the Andes appear pale green. Light-blue patches in the mountains to the north are glaciers.

  13. Reconstruction of Late Cretaceous Magmatic Arcs in the Northern Andes: Single Versus Multiple Arc Systems

    NASA Astrophysics Data System (ADS)

    Cardona, A.; Jaramillo, J. S.; Leon, S.; Hincapie, S.; Mejia, D.; Patino, A. M.; Vanegas, J.; Zapata, S.; Valencia, V.; Jimenez, G.; Monsalve, G.

    2014-12-01

    Although magmatic rocks are major tracers of the geological evolution of convergent margins, pre-collisional events such as subduction erosion, collisional thrusting or late collisional strike slip segmentation may difficult the recognizing of multiple arc systems and therefore the existence of paleogeographic scenarios with multiple subduction systems. New field, U-Pb geochronology and whole rock geochemistry constraints from the northwestern segment of the Central Cordillera in the states of Antioquia and Caldas (Colombia) are used to understand the nature of the Late Cretaceous arc magmatism and evaluate the existence of single or multiple Pacific and Caribbean arc systems in the growth of the Northwestern Andes. The new results integrated with additional field and published information is used to suggest the existence of at least three different magmatic arcs. (1) An Eastern Continental arc built within a well defined Permian to Triassic continental crust that record a protracted 90-70 Ma magmatic evolution, (2) a 90-80 arc formed within attenuated continental crust and associated oceanic crust, (3) 90-88 Ma arc formed over a Late Cretaceous plateau crust. The eastern arcs were formed as part of double eastern vergent subduction system, where the most outboard arc represent a fringing arc formed over detached fragments of continental crust, whereas the easternmost continental arc growth by the closure an subduction of and older and broad Triassic to Early Jurassic back-arc ocean. Its closure also end up in ophiolite emplacement. The third allochtonous oceanic arc was formed over the Caribbean plateau crust and was accreted to the continental margin in the Late Cretaceous. Ongoing paleomagnetic, deformational, gravimetric and basin analysis will be integrate to test this model and understand the complex Late Cretaceous tectonic evolution of the Northern Andes.

  14. Preliminary Results From the CAUGHT Experiment: Investigation of the North Central Andes Subsurface Using Receiver Functions and Ambient Noise Tomography

    NASA Astrophysics Data System (ADS)

    Ryan, J. C.; Ward, K. M.; Porter, R. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.

    2011-12-01

    Jamie Ryan, Kevin M. Ward, Ryan Porter, Susan Beck, George Zandt, Lara Wagner, Estela Minaya, and Hernando Tavera The University of Arizona The University of North Carolina San Calixto Observatorio, La Paz, Bolivia IGP, Lima, Peru In order to investigate the interplay between crustal shortening, lithospheric removal, and surface uplift we have deployed 50 broadband seismometers in northwestern Bolivia and southern Peru as part of the interdisciplinary Central Andean Uplift and Geodynamics of High Topography (CAUGHT) project. The morphotectonic units of the central Andes from west to east, consist of the Western Cordillera, the active volcanic arc, the Altiplano, an internally drained basin (~4 km elevation), the Eastern Cordillera, the high peaks (~6 km elevation) of an older fold and thrust belt, the Subandean zone, the lower elevation active fold and thrust belt, and the foreland Beni basin. Between northwestern Bolivia and southern Peru, the Altiplano pinches out north of Lake Titicaca as the Andes narrow northward. The CAUGHT seismic instruments were deployed between 13° to 18° S latitudes to investigate the crust and mantle lithosphere of the central Andes in this transitional zone. In northwest Bolivia, perpendicular to the strike of the Andes, there is a total of 275 km of documented upper crustal shortening (15° to 17°S) (McQuarrie et al, 2008). Associated with the shortening is crustal thickening and possibly lithospheric removal as the thickening lithospheric root becomes unstable. An important first order study is to compare upper crustal shortening estimates with present day crustal thickness. To estimate crustal thickness, we have calculated receiver functions using an iterative deconvolution method and used common conversion point stacking along the same profile as the geologically based shortening estimates. In our preliminary results, we observed a strong P to S conversion corresponding to the Moho at approximately 60-65 km depth underneath the

  15. Gene Knockdown of Venezuelan Equine Encephalitis Virus E2 Glycoprotein Using DNA-Directed RNA Interference

    DTIC Science & Technology

    2006-12-01

    e _s~u~m mary - Introduction: Alphaviruses are a large family of RNA viruses that can cause acute infection resulting in arthritis and encephalitis...One of the important alphaviruses is the Venezuelan equine encephalitis virus. This virus has been linked to a number of outbreaks in both North and... replication of VEE virus in vitro. Bhogal, H.S., McLaws, L.J., and Jager, S.J. 2006. Gene Knockdown of Venezuelan Equine Encephalitis Virus E2

  16. Reproductive biology of freshwater fishes from the Venezuelan floodplains.

    PubMed

    Guerrero, H Y; Cardillo, E; Poleo, G; Marcano, D

    2009-03-01

    This review describes the endocrine changes that occur during the annual reproductive cycle of Pygocentrus cariba, Pimelodus blochii, and Oxydoras sifontesi and their relationships with the environmental characteristics of Venezuelan floodplains. Most reproductive studies of teleosts have focused on changes that occur during annual cycles in temperate species but, in tropical fish, this has been examined less frequently. P. cariba, P. blochii, and O. sifontesi are seasonal breeders widely distributed along the Orinoco River. Under natural conditions they have an annual gonadal cycle closely related to changes in the annual hydrology cycle of the Orinoco River which defines two seasons on the floodplain: inundation and isolation. The reproductive cycle of these species seems to be controlled by cues from the external environment. Relevant data about gonadal maturation, for example gonadosomatic index and sexual hormones secretion, are contrasted. The role of catecholamines in neuroendocrine control of the reproductive axis is also considered in this work.

  17. Venezuelan Caribbean Sea under the threat of TBT.

    PubMed

    Paz-Villarraga, César Augusto; Castro, Italo B; Miloslavich, Patricia; Fillmann, Gilberto

    2015-01-01

    Although environmental tributyltin (TBT) contamination is considered a solved problem, imposex occurrence in Plicopurpura patula as well as butyltins (BTs) contamination in sediments and tissues were detected along 700 km of the Caribbean coastal shore. Areas under the influence of five main ports of Venezuela were covered, as well as large marinas and sites located away from expected sources. Marinas were the most contaminated areas, whilst imposex incidence and TBT levels were relatively low in areas nearby commercial harbors. Thus, it is evident that marinas have become the main source of fresh TBT to the region. This might explain why imposex incidence seems to be widely distributed along the Venezuelan coast, since leisure boats are circulating along the whole coastal region. In fact, this could be the pattern for other areas of the Caribbean Sea.

  18. LANDSAT imagery of the Central Andes

    NASA Technical Reports Server (NTRS)

    Komer, C. A.; Morgan, P.

    1986-01-01

    The central Andes of South America extend from approximately 14 deg. S to 28 deg. S as an unbroken chain of mountains and volcanoes over 2000 km long. It is here that the Nazca plate dives under the South American plate at angles varying from 10 deg to 30 deg. Very little is known about the volcanoes comprising this classic, subduction-type plate margin. A catalogue of the volcanoes in the central Andes is being prepared by Dr. P.W. Francis and Dr. C.A. Wood at the NASA Lunar and Planetary Institute. At present, more than 800 volcanoes of Cenozoic age have been recognized in the chain, with an estimated 75-80 major, active Quarternary volcanoes. Approximately one hundred 1536 x 1536 pixel color composite Optronics positives were produced from six full LANDSAT Thermatic Mapper scenes and three partial TM scenes. These positives cover a large portion of the central Andes. The positives were produced from LANDSAT data using the VAX imaging package, LIPS. The scenes were first transferred from magnetic tape to disk. The LIPS package was then used to select volcanically interesting areas which were then electronically enhanced. Finally, the selected areas were transferred back to tape and printed on the Optronics equipment. The pictures are color composites using LANDSAT TM bands 7,4, and 2 in the red, green, and blue filters, respectively.

  19. A new case of an Holarctic element in the Colombian Andes: first record of Cordyla Meigen (Diptera, Mycetophilidae) from the Neotropical region

    PubMed Central

    Kurina, Olavi; Oliveira, Sarah Siqueira

    2015-01-01

    Abstract Three new species of Mycetophilidae – Cordyla monticola sp. n., Cordyla pseudopusilla sp. n. and Cordyla reducta sp. n. – are described from the Colombian Andes, representing the first described species of Cordyla Meigen from the Neotropical region. Colour photos of their habitus, wing and terminalia are provided. The morphological affinities of male terminalia are discussed in a worldwide context. The distributional pattern of the genus clearly indicates a case of northern elements reaching the north-western region of the Neotropics that corresponds to a secondary extension of a Holarctic clade to the south. PMID:26445929

  20. The basement of the Eastern Cordillera, Colombia: An allochthonous terrane in northwestern South America

    NASA Astrophysics Data System (ADS)

    Forero Suarez, A.

    The fault system of the Borde Llanero of Colombia represents the limit between two early Paleozoic geologic provinces: the Guiana Shield (Gondwana) to the east, and an allochthonous terrane — formerly a piece of the North American continent — to the west. The Baudó Range, the Western Cordillera, and the western flank of the Central Cordillera are the result of post-Jurassic accretion. In contrast the pre-Emsian metamorphic rocks of the eastern flank of the Central Cordillera, of the Eastern Cordillera of Colombia, and of the Mérida Andes correspond to an allochthonous terrane that was accreted to the north-western continental border of South America during the collision between North America and Gondwana in Silurian-Early Devonian times. Geochronologic and petrographic data indicate the presence of the Grenvillian granulite belt, represented by the Garzón-Sierra Nevada de Santa Marta belt. This belt is separated from the Guiana Shield by a magmatic tract which is parallel to the Borde Llanero of Venezuela and Colombia. The late Paleozoic regional metamorphism in the Northern Andes of Colombia occurred during Late Silurian-Early Devonian times. Since the late Emsian, a sedimentary cycle was initiated on this allochthonous basement. The faunal records of northwestern South America and the North American continent are indistinguishable for that time. This similarity clearly shows that both northwestern South America and the North American regions of the Appalachians and New Mexico belong to the same paleobiogeographic province. The faunal communication in this case supports the idea of the immediate neighborhood of the two continents.

  1. ANDES TOOLS: Promotional slides for Industrial Clients

    DTIC Science & Technology

    2015-09-03

    Briefing Charts 3. DATES COVERED (From - To) 10 August 2015 – 3 September 2015 4. TITLE AND SUBTITLE ANDES TOOLS: Promotional slides for Industrial ...Clients 5a. CONTRACT NUMBER FA9300-13-C-2014 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Tim Holmes, D.Sc. 5d. PROJECT NUMBER 5e. TASK... Industrial Clients PA Case Number: #15479; Clearance Date: 9/3/2015 14. ABSTRACT Briefing Charts/Viewgraphs 15. SUBJECT TERMS N/A 16. SECURITY

  2. Characterization of genetic variability of Venezuelan equine encephalitis viruses

    DOE PAGES

    Gardner, Shea N.; McLoughlin, Kevin; Be, Nicholas A.; ...

    2016-04-07

    Venezuelan equine encephalitis virus (VEEV) is a mosquito-borne alphavirus that has caused large outbreaks of severe illness in both horses and humans. New approaches are needed to rapidly infer the origin of a newly discovered VEEV strain, estimate its equine amplification and resultant epidemic potential, and predict human virulence phenotype. We performed whole genome single nucleotide polymorphism (SNP) analysis of all available VEE antigenic complex genomes, verified that a SNP-based phylogeny accurately captured the features of a phylogenetic tree based on multiple sequence alignment, and developed a high resolution genome-wide SNP microarray. We used the microarray to analyze a broadmore » panel of VEEV isolates, found excellent concordance between array- and sequence-based SNP calls, genotyped unsequenced isolates, and placed them on a phylogeny with sequenced genomes. The microarray successfully genotyped VEEV directly from tissue samples of an infected mouse, bypassing the need for viral isolation, culture and genomic sequencing. Lastly, we identified genomic variants associated with serotypes and host species, revealing a complex relationship between genotype and phenotype.« less

  3. Venezuelan equine encephalitis virus infection of spiny rats.

    PubMed

    Carrara, Anne-Sophie; Gonzales, Gonzales; Ferro, Cristina; Tamayo, Margarita; Aronson, Judith; Paessler, Slobodan; Anishchenko, Michael; Boshell, Jorge; Weaver, Scott C

    2005-05-01

    Enzootic strains of Venezuelan equine encephalitis virus (VEEV) circulate in forested habitats of Mexico, Central, and South America, and spiny rats (Proechimys spp.) are believed to be the principal reservoir hosts in several foci. To better understand the host-pathogen interactions and resistance to disease characteristic of many reservoir hosts, we performed experimental infections of F1 progeny from Proechimys chrysaeolus collected at a Colombian enzootic VEEV focus using sympatric and allopatric virus strains. All animals became viremic with a mean peak titer of 3.3 log10 PFU/mL, and all seroconverted with antibody titers from 1:20 to 1:640, which persisted up to 15 months. No signs of disease were observed, including after intracerebral injections. The lack of detectable disease and limited histopathologic lesions in these animals contrast dramatically with the severe disease and histopathologic findings observed in other laboratory rodents and humans, and support their role as reservoir hosts with a long-term coevolutionary relationship to VEEV.

  4. [Anthropometric characteristics and skeletal maturity of male Venezuelan swimmers].

    PubMed

    Salazar-Lioggiodice, Marinés; Arroyo, Esteban; Pérez, Betty

    2006-06-01

    Knowledge of the morph-physiological conditions of young athletes, it of the utmost importance for planning better trainning programs and to identify those characteristics that lead to a better performance. This paper aims to classify a group of 114 male Venezuelan swimmers of the Miranda State contingent, aged between 7.00 and 18.99 years old, based on their anthropometric characteristics and skeletal maturity. For this purpose multivariate methods: Analysis of Principal Components (APC) and the Automatic Classification were employed. Anthropometric variables followed the International Society for the Advancement of Kinantropometry (ISAK) guidelines. Skeletal maturity and five indexes of body composition: brachial, crural, cormic and acromiale-iliac indexes, were additionally considered in the analysis. Three groups emerged very well defined and homogenous within and between groups. The first group identifies the younger swimmers with the smallest values in corporal dimensions. The second group comprises those swimmers characterized fundamentally by a greater development of the bicrestal diameter. In the third group, greater values of the anthropometrical variables were found, that shaped the typical profile of the swimmers, mainly characterized by a trapezoidal trunk. Most of the swimmers are advanced in skeletal age related to chronological age. This clustering of the swimmers permits a suitable way to identify the bio-morphological characteristics of the athletes.

  5. [Pneumocystosis in Venezuelan patients: epidemiology and diagnosis (2001-2006)].

    PubMed

    Panizo, María Mercedes; Reviákina, Vera; Navas, Trina; Casanova, Karina; Sáez, Alejandro; Guevara, Rafael Napoleón; Cáceres, Ana María; Vera, Raúl; Sucre, Carlos; Arbona, Esther

    2008-12-31

    The objective of this work was to investigate the epidemiology of pneumocystosis in Venezuelan patients utilizing a retrospective study during a six year period. One hundred and twenty nine clinical samples collected from patients with AIDS, cancer and non-AIDS-non-cancer low respiratory tract infection patients were processed by direct immunofluorescence technique. Pneumocystosis was diagnosed in 30 patients with a general frequency of 23.3%, which varied according to the patient's group: 36.6% in AIDS patients, 38% in cancer patients, and 10.4% in non-AIDS-non-cancer low respiratory tract infection patients. This study demonstrated the existence of differences in pneumocystosis frequency related to the patient's underlying disease, and that the illness is an important health problem in immunocompromised patients in Venezuela. Pneumocystosis must be suspected in non-immunocompromised patients with signs and symptoms of low respiratory tract infection, and the study of this illness must include COPD and cancer patients. Direct immunofluorescence is a useful technique for pneumocystosis diagnosis, however, it requires an optimal sample and skilled personnel in the laboratory.

  6. Characterization of Genetic Variability of Venezuelan Equine Encephalitis Viruses.

    PubMed

    Gardner, Shea N; McLoughlin, Kevin; Be, Nicholas A; Allen, Jonathan; Weaver, Scott C; Forrester, Naomi; Guerbois, Mathilde; Jaing, Crystal

    2016-01-01

    Venezuelan equine encephalitis virus (VEEV) is a mosquito-borne alphavirus that has caused large outbreaks of severe illness in both horses and humans. New approaches are needed to rapidly infer the origin of a newly discovered VEEV strain, estimate its equine amplification and resultant epidemic potential, and predict human virulence phenotype. We performed whole genome single nucleotide polymorphism (SNP) analysis of all available VEE antigenic complex genomes, verified that a SNP-based phylogeny accurately captured the features of a phylogenetic tree based on multiple sequence alignment, and developed a high resolution genome-wide SNP microarray. We used the microarray to analyze a broad panel of VEEV isolates, found excellent concordance between array- and sequence-based SNP calls, genotyped unsequenced isolates, and placed them on a phylogeny with sequenced genomes. The microarray successfully genotyped VEEV directly from tissue samples of an infected mouse, bypassing the need for viral isolation, culture and genomic sequencing. Finally, we identified genomic variants associated with serotypes and host species, revealing a complex relationship between genotype and phenotype.

  7. Characterization of genetic variability of Venezuelan equine encephalitis viruses

    SciTech Connect

    Gardner, Shea N.; McLoughlin, Kevin; Be, Nicholas A.; Allen, Jonathan; Weaver, Scott C.; Forrester, Naomi; Guerbois, Mathilde; Jaing, Crystal

    2016-04-07

    Venezuelan equine encephalitis virus (VEEV) is a mosquito-borne alphavirus that has caused large outbreaks of severe illness in both horses and humans. New approaches are needed to rapidly infer the origin of a newly discovered VEEV strain, estimate its equine amplification and resultant epidemic potential, and predict human virulence phenotype. We performed whole genome single nucleotide polymorphism (SNP) analysis of all available VEE antigenic complex genomes, verified that a SNP-based phylogeny accurately captured the features of a phylogenetic tree based on multiple sequence alignment, and developed a high resolution genome-wide SNP microarray. We used the microarray to analyze a broad panel of VEEV isolates, found excellent concordance between array- and sequence-based SNP calls, genotyped unsequenced isolates, and placed them on a phylogeny with sequenced genomes. The microarray successfully genotyped VEEV directly from tissue samples of an infected mouse, bypassing the need for viral isolation, culture and genomic sequencing. Lastly, we identified genomic variants associated with serotypes and host species, revealing a complex relationship between genotype and phenotype.

  8. Challenging the neoliberal trend: the Venezuelan health care reform alternative.

    PubMed

    Muntaner, Carles; Salazar, René M Guerra; Rueda, Sergio; Armada, Francisco

    2006-01-01

    Throughout the 1990s, all Latin American countries but Cuba implemented to varying degrees health care sector reforms underpinned by a neoliberal paradigm that redefined health care as less of a social right and more of a market commodity. These health care sector reforms were couched in the broader structural adjustment of Latin American welfare states prescribed consistently by international financial institutions since the mid-1980s. However, since 2003, Venezuela has been developing an alternative to this neoliberal trend through its health care reform program called Misión Barrio Adentro (Inside the Neighbourhood). In this article, we introduce Misión Barrio Adentro in its historical, political, and economic contexts. We begin by analyzing Latin American neoliberal health sector reforms in their political economic context, with a focus on Venezuela. The analysis reveals that the major beneficiaries of both broader structural adjustment of Latin American welfare states and neoliberal health reforms have been transnational capital interests and domestic Latin American elites. We then provide a detailed description of Misión Barrio Adentro as a challenge to neoliberalism in health care in its political economic context, noting the role played in its development by popular resistance to neoliberalism and the unique international cooperation model upon which it is based. Finally, we suggest that the Venezuelan experience may offer valuable lessons not only to other low- to middle-income countries, but also to countries such as Canada.

  9. Sandstone caves on Venezuelan tepuis: Return to pseudokarst?

    NASA Astrophysics Data System (ADS)

    Aubrecht, R.; Lánczos, T.; Gregor, M.; Schlögl, J.; Šmída, B.; Liščák, P.; Brewer-Carías, Ch.; Vlček, L.

    2011-09-01

    Venezuelan table mountains (tepuis) host the largest arenite caves in the world. The most frequently used explanation of their origin so far was the "arenization" theory, involving dissolution of quartz cement around the sand grains and subsequent removing of the released grains by water. New research in the two largest arenite cave systems - Churi-Tepui System in Chimanta Massif and Ojos de Cristal System in Roraima Tepui showed that quartz dissolution plays only a minor role in their speleogenesis. Arenites forming the tepuis are not only quartzites but they display a wide range of lithification and breakdown, including also loose sands and sandstones. Speleogenetic processes are mostly concentrated on the beds of unlithified sands which escaped from diagenesis by being sealed by the surrounding perfectly lithified quartzites. Only the so-called "finger-flow" pillars testify to confined diagenetic fluids which flowed in narrow channels, leaving the surrounding arenite uncemented. Another factor which influenced the cave-forming processes by about 30% was lateritization. It affects beds formed of arkosic sandstones and greywackes which show strong dissolution of micas, feldspars and clay minerals, turning then to laterite ("Barro Rojo"). The main prerequisite to rank caves among karst phenomena is dissolution. As the dissolution of silicate minerals other than quartz appears to play not only a volumetrically important role but even a trigger role, these arenitic caves may be ranked as karst.

  10. Temporal distribution of heavy metal concentrations in oysters Crassostrea rhizophorae from the central Venezuelan coast.

    PubMed

    Alfonso, Juan A; Handt, Helga; Mora, Abrahan; Vásquez, Yaneth; Azocar, José; Marcano, Eunice

    2013-08-15

    The oyster Crassostrea rhizophorae is a bivalve abundant in Venezuelan estuaries and consumed by local populations. No known values have been reported on trace metals in oysters from the central Venezuelan coast. We report the concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V and Zn in the soft parts of C. rhizophorae, which were collected bimonthly between March 2008 and March 2009, at two sampling areas from the Central Venezuelan Coast: Buche estuary and Mochima estuary. Our results show that for each metal there is a similar temporal variation pattern. The concentrations of the heavy metals reported in this work are useful as reliable baselines and can be used for comparison in future environment studies. Concentrations in C. rhizophorae from the Buche estuary can be interpreted to be high on a global scale for Cd, Cu, Ni and Mn, indicating atypically raised bioavailabilities.

  11. Determination of FeS(2) in Venezuelan laterites after a sulphurization process.

    PubMed

    La Brecque, J J; Rosales, P A

    1979-11-01

    A technique is presented for determination of FeS(2) in Venezuelan laterites after a sulphurization process. The determination is based on a reaction with water followed by a turbidimetric determination of sulphate ions in solution. The effect of the reaction time and of the particle size is investigated. Data are given showing the precision to be better than 3%, and the accuracy was studied by preparation of a series of synthetic samples of FeS(2), FeS and Venezuelan laterite.

  12. PORTRAYALS OF COLOMBIAN AND VENEZUELAN IMMIGRANT ORGANISATIONS IN THE UNITED STATES

    PubMed Central

    SANCHEZ-R, MAGALY; AYSA-LASTRA, MARIA

    2014-01-01

    This article compares the public images of Colombian and Venezuelan immigrant organisations in the United States. Immigrant organisations’ webpages and the expression of their main aims and goals serve to identify their major concerns as they create public images not only for the organisation but for the immigrant community itself. To interpret the immigrant organisations’ public images and their goals, we offer a multilevel study that considers immigrants’ contexts of exit, which are related to the motivation of migrate and the particular sociodemographic makeup of immigrant groups. This paper adds the Venezuelan immigrant experience to the literature on immigrant organisations. PMID:25324586

  13. [Human rights. Right to health. Right to health information. The Venezuelan biomedical journals].

    PubMed

    Stegemann, Herbert

    2013-06-01

    Venezuelan Biomedical journals have been confronting, for several years, a gradual decline both, from the standpoint of their management and in the quality of their editorial content. At its highest level, Venezuela had about sixty different titles. But irregular financial support, as well as the lack of a clear official policy, regarding these scientific activities, were some of the reasons that have contributed to this decline. Several recent Venezuelan and international documents provide an important legal support for the design of new official policies and government responsibilities. There is now a valid opportunity to profit from new tools to evaluate and improve the quality of our scientific and editorial activities.

  14. The Southern Andes Between 36o and 40o S Latitude: Seismicity and Average Velocities

    NASA Astrophysics Data System (ADS)

    Bohm, M.; Bruhn, C.; Asch, G.; Bataille, K.; Rietbrock, A.; ISSA Working Group,; ISSA Working Group,; ISSA Working Group,; ISSA Working Group,; ISSA Working Group,

    2001-12-01

    A temporary seismological network was installed as part of the project ISSA 2000 (Integrated Seismological experiment in the Southern Andes) between 36o and 40o S above the active continental margin in the Southern Andes reaching from the Chilean Pacific coast to 68o W in Argentina. The network consisted of 62 seismographs recording continuously from November 1999 to April 2000. We recorded on average 3 to 4 local earthquakes per day, mainly concentrated in the northwestern part of the network, resulting in a data set of 300 seismic events. High quality P and S arrival times of 120 earthquakes were inverted simultanously for 1-D velocity structure and hypocentral coordinates. Precise hypocenter locations of local earthquakes are determinted resulting in the first accurate image of the Wadati-Benioff zone south of Concepcion. The 1-D velocity model serves as initial reference model of seismic velocity tomographic studies, preliminary results of which will be presented. A further research interest of this seismological experiment is the determination of source mechanisms. Moment tensor inversions provide important information on the current stress field. It is postulated by several authors that dehydration processes are the cause of intermediate depth earthquakes while the focal mechanisms in the seismic coupling zone will be controlled by the deformation processes of the continental crust. A distinct non double couple part of the moment tensor will be expected in the zones of dehydration processes. The recorded data base allows a detailed investigation of local events in a higher frequency range. Instead of using the seismograms directly, the inversion for the moment tensor can also be performed on amplitude spectra. This method has the advantage that slight misalignments between seismograms and Greens functions do not bias the outcome, because the phase spectrum is not used at all.

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

    NASA Technical Reports Server (NTRS)

    Vincent, R. K.

    1980-01-01

    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.

  16. Role of Cytokines and Neurotrophins in the Central Nervous System in Venezuelan Equine Encephalitis Pathogenesis

    DTIC Science & Technology

    2001-03-21

    to, Crohn s disease (63), atherosclerotic plaques (47), autoimmune encephalomyelitis (96), Japanese encephalitis (132), and Venezuelan equine...astrocytes.................................................58 xi LIST OF ABBREVIATIONS AD Alzheimer s Disease AIDS Acquired Immune Deficiency Syndrome...line derived neurotrophic factor HAM HTLV-Associated Myelopathy HD Huntington s Disease HIV Human Immunodeficiency Virus HTLV Human T-Lymphotrophic

  17. 9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western,...

  18. 9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western,...

  19. 9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western,...

  20. 9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western,...

  1. 9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western,...

  2. The Glaciation of the Ecuadorian Andes

    NASA Astrophysics Data System (ADS)

    Schubert, Carlos

    This pleasing book fills the gap in the knowledge about Pleistocene and recent glaciation between Colombia and Peru. A significant amount of data exists already for Colombia and Venezuela and for Peru, Bolivia, and, particularly, Chile. Hastenrath has now given us a description of glaciers and glaciation underneath the equator in the Andes.The book begins with brief summaries of the physiography and the atmospheric circulation, which give the general setting of Ecuador. Then follow detailed descriptions of the glaciers and glacial morphology of all the important mountains of the Western and Eastern Cordilleras. These are well illustrated, and a particularly useful feature is the comparison of old photographs and paintings of glaciers with modern photographs, many taken by the author. All illustrate the spectacular retreat of the glaciers in the Ecuadorian Andes during the last century and correlate quite well with observations elsewhere. This retreat is snown quantitatively in Table 4, in terms of decrease in glacier-covered area since the glacial advance of moraine stage III. The area of present-day glaciers is about 10% of the area during that stage (compared with about 1.5% in the Sierra Nevada de Mérida, Venezuela). A series of maps show the glacial morphology of the mountains (unfortunately, some of the maps have been included within the binding, thus losing some information; they could have been reduced somewhat to fit a single page or, if too large, could have been included in the pocket, together with the map of Chimborazo-Carihuairazo).

  3. [Lipid profile in Venezuelan preschoolers by socioeconomic status].

    PubMed

    Velásquez, Emma; Adela Barón, María; Solano, Liseti; Páez, Maria; Llovera, Daisy; Portillo, Zulay

    2006-03-01

    Epidemiological studies have shown that unfavorable serum lipids levels in childhood are predictors of development of atherosclerosis lesions in adulthood. We assessed the lipid profile of 297 Venezuelan preschool children (4-7 years old) from two socioeconomic levels in order to compare them by this characteristic. Their social level was determined according to modified Graffar method, and two groups were obtained: high socioeconomic status (HSES, n=103) and low socioeconomic status (LSES, n=194). Nutritional anthropometric evaluation was performed by weight to height, and NCHS/OMS cut-off point was used. Lipid profile was determined by colorimetric biochemical methods and atherogenic risks factors were calculated. Underweight for HSES was 5.8% and for LSES: 14.9%, while normal status was 78.6% and 70.1%, and overweight was 15.5% and 14.9%, respectively. Mean values for triglycerides were 0.66 +/- 0.27and 0.76 +/- 0.31 mmol/L, total cholesterol (TC): 3.61 +/- 0.65 and 2.98 +/- 0.71 mmol/L, HDL-C: 1.04 +/- 0.18 and 0.62 +/- 0.16 mmol/L, LDL-C: 2.27 +/- 0.61 and 2.01 +/- 0.71 mmol/L, TC/HDL-C: 3.5 +/- 0.78 and 5.0 +/- 1.5; LDL-C/HDL-C: 2.0 +/- 0.71 and 3.4 +/- 1.4 with significant differences between HSES and LSES as shown respectively. A significant association was found (p < 0.01) between lipid values and socioeconomic status, being the LSES preschoolers those with the higher atherogenic risk. Its pattern was of lower HDL-C levels, and higher TC/HDL-C and LDL-C/HDL-C ratio. Comparisons of lipid profile by nutritional status or gender did not show significant differences. Findings indicate that children from low socioeconomic status are at a higher risk for cardiovascular disease and atherosclerosis than children from high socioeconomic status.

  4. Three new species of woodlizards (Hoplocercinae, Enyalioides) from northwestern South America

    PubMed Central

    Torres-Carvajal, Omar; Venegas, Pablo J.; de Queiroz, Kevin

    2015-01-01

    Abstract The discovery of three new species of Enyalioides from the tropical Andes in Ecuador and northern Peru is reported. Enyalioides altotambo sp. n. occurs in northwestern Ecuador and differs from other species of Enyalioides in having dorsal scales that are both smooth and homogeneous in size, a brown iris, and in lacking enlarged, circular and keeled scales on the flanks. Enyalioides anisolepis sp. n. occurs on the Amazonian slopes of the Andes in southern Ecuador and northern Peru and can be distinguished from other species of Enyalioides by its scattered, projecting large scales on the dorsum, flanks, and hind limbs, as well as a well-developed vertebral crest, with the vertebrals on the neck at least three times higher than those between the hind limbs. Enyalioides sophiarothschildae sp. n. is from the Amazonian slopes of the Cordillera Central in northeastern Peru; it differs from other species of Enyalioides in having caudal scales that are relatively homogeneous in size on each caudal segment, a white gular region with a black medial patch and several turquoise scales in males, as well as immaculate white labials and chin. A molecular phylogenetic tree of 18 species of hoplocercines is presented, including the three species described in this paper and Enyalioides cofanorum, as well as an updated identification key for species of Hoplocercinae. PMID:25901116

  5. Three new species of woodlizards (Hoplocercinae, Enyalioides) from northwestern South America.

    PubMed

    Torres-Carvajal, Omar; Venegas, Pablo J; de Queiroz, Kevin

    2015-01-01

    The discovery of three new species of Enyalioides from the tropical Andes in Ecuador and northern Peru is reported. Enyalioidesaltotambo sp. n. occurs in northwestern Ecuador and differs from other species of Enyalioides in having dorsal scales that are both smooth and homogeneous in size, a brown iris, and in lacking enlarged, circular and keeled scales on the flanks. Enyalioidesanisolepis sp. n. occurs on the Amazonian slopes of the Andes in southern Ecuador and northern Peru and can be distinguished from other species of Enyalioides by its scattered, projecting large scales on the dorsum, flanks, and hind limbs, as well as a well-developed vertebral crest, with the vertebrals on the neck at least three times higher than those between the hind limbs. Enyalioidessophiarothschildae sp. n. is from the Amazonian slopes of the Cordillera Central in northeastern Peru; it differs from other species of Enyalioides in having caudal scales that are relatively homogeneous in size on each caudal segment, a white gular region with a black medial patch and several turquoise scales in males, as well as immaculate white labials and chin. A molecular phylogenetic tree of 18 species of hoplocercines is presented, including the three species described in this paper and Enyalioidescofanorum, as well as an updated identification key for species of Hoplocercinae.

  6. Angiosperm flora on the páramos of northwestern Colombia: diversity and affinities.

    PubMed

    Alzate-Guarín, Fernando; Murillo-Serna, Jhon Steven

    2016-01-01

    Páramos are high-elevation isolated ecosystems in the Andes characterized by specific flora. This flora includes a number of endemic species and some taxa phylogenetically related to temperate lineages (van der Hammen and Cleef 1986). There are six páramo units or complexes in the Department of Antioquia, located in northwestern Colombia. For five years, we conducted botanic explorations in order to quantify the richness of angiosperm flora in these units. We estimate the richness of angiosperms in these páramos at 693 species, 277 genera, and 86 families, which represent almost 10% of the floral diversity in Antioquia, but contained in only 0.7% of its area. We found that Frontino-Urrao is the most species-rich páramo with 465 species from 225 genera. Our results show that the most diverse angiosperm families of the páramos of Antioquia are Asteraceae, Orchidaceae, Melastomataceae, and Poaceae, which together represent 245 species. Groupings between páramos by Sørensen's similarity index show that the complexes of the Central Andes Cordillera form a cluster of greater affinity than Páramos from other regions. Of the species found, 80 have a CITES or IUCN diagnosis. The expeditions allowed the identification of 21 species not previously registered in Antioquia and a considerable number of endemisms (35 species), further proof of the high plant diversity in these ecosystems.

  7. Angiosperm flora on the páramos of northwestern Colombia: diversity and affinities

    PubMed Central

    Alzate-Guarín, Fernando; Murillo-Serna, Jhon Steven

    2016-01-01

    Abstract Páramos are high-elevation isolated ecosystems in the Andes characterized by specific flora. This flora includes a number of endemic species and some taxa phylogenetically related to temperate lineages (van der Hammen and Cleef 1986). There are six páramo units or complexes in the Department of Antioquia, located in northwestern Colombia. For five years, we conducted botanic explorations in order to quantify the richness of angiosperm flora in these units. We estimate the richness of angiosperms in these páramos at 693 species, 277 genera, and 86 families, which represent almost 10% of the floral diversity in Antioquia, but contained in only 0.7% of its area. We found that Frontino-Urrao is the most species-rich páramo with 465 species from 225 genera. Our results show that the most diverse angiosperm families of the páramos of Antioquia are Asteraceae, Orchidaceae, Melastomataceae, and Poaceae, which together represent 245 species. Groupings between páramos by Sørensen’s similarity index show that the complexes of the Central Andes Cordillera form a cluster of greater affinity than Páramos from other regions. Of the species found, 80 have a CITES or IUCN diagnosis. The expeditions allowed the identification of 21 species not previously registered in Antioquia and a considerable number of endemisms (35 species), further proof of the high plant diversity in these ecosystems. PMID:27829798

  8. Title Sheet, National Home for Disabled Volunteer Soldiers, Northwestern Branch ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Title Sheet, National Home for Disabled Volunteer Soldiers, Northwestern Branch - National Home for Disabled Volunteer Soldiers, Northwestern Branch, 5000 West National Avenue, Milwaukee, Milwaukee County, WI

  9. Late Tertiary northwestward-vergent thrusting in Valle del Cauca, Colombian Andes

    SciTech Connect

    Alfonso, C.A.; Sacks, P.E.; Secor, D.T. Jr.; Cordoba, F.

    1989-03-01

    The Valle del Cauca is a topographic basin situated between the Cordillera Central and the Cordillera Occidental in the Colombian Andes. The basement is Mesozoic mafic igneous rock of the Volcanic and Amaime Formations and clastic sediments and chert of the Espinal and Cisneros Formations. The basement was intruded by middle Cretaceous granodiorites (including the Batolito de Buga) and was deformed and metamorphosed to greenschist facies. The Mesozoic rocks originated in an oceanic setting and were accreted to northwestern South America during the Cretaceous or early Tertiary. Unconformably overlying the Mesozoic basement are the Eocene and Oligocene Vijes (marine limestone) and Guachinte and Cinta de Piedra (fluvial and deltaic sandstone and mudstone). In the Cordillera Central, the Cinta de Piedra is unconformably overlain by fanglomerate of the Miocene La Paila Formation. These clastics coarsen and thicken eastward. Geologic mapping and structural analyses show that the Mesozoic basement and its Tertiary cover are faulted and folded. Folds are asymmetric and overturned westward. Faults dip at shallow to moderate angles to the east and carry older sedimentary or basement rocks westward over younger rocks.

  10. Deformation of Northwestern South America from GPS Geodesy

    NASA Astrophysics Data System (ADS)

    Mora-Paez, H.; La Femina, P. C.; Mothes, P. A.; Ruiz, A. G.; Fernandes, R. M.

    2013-12-01

    The North Andes block (NAB) is a hypothesized tectonic block that migrates (escapes) north-northeast relative to a stable South American reference frame. The motion of this block is thought-to-be derived by the collision of the Carnegie Ridge in southern Ecuador and/or by oblique convergence and high degrees of interplate coupling north of the ridge (i.e., strain partitioning). At the latitude of Ecuador, the NAB is defined by transpressional deformation accommodating east-northeastward motion along its boundary with South America. In southern to central Colombia, the NAB is dissected by several mapped and prominent regional shear zones. At these latitudes the NAB may be bound to the west by the Choco block and the transpressional Atrato-Uraba fault system and to the east by the Guayaquil-Algeciras fault system. And in northern Colombia the Caribbean - South America plate boundary is defined by the NAB and proposed Maracaibo and Guajira blocks. We investigate the deformation of northwestern South America, including the kinematics of NAB utilizing a new velocity field based on continuous GPS and existing episodic GPS data in Ecuador, Colombia, Venezuela and Panama. We reference these new velocities to a newly estimated Euler vector for the South America plate based on inversion of cGPS data from stations east of the Andes. The new velocity field and published earthquake slip vectors are inverted to solve for the Euler vectors of the NAB, Choco, Panama, Maracaibo and Guajira blocks and interseismic elastic strain accumulation (interseismic coupling) on block-bounding faults using a block modeling approach. We test a suite of block models to investigate the tectonic nature of the NAB along strike and the style of faulting in the upper plate accommodating block motion. Through the estimation of elastic strain accumulation on all block-bounding faults, we improve the understanding of interseismic coupling along a convergent margin capable of producing M>8 earthquakes

  11. ANDES Measurements for Advanced Reactor Systems

    NASA Astrophysics Data System (ADS)

    Plompen, A. J. M.; Hambsch, F.-J.; Kopecky, S.; Nyman, M.; Rouki, C.; Salvador Castiñeira, P.; Schillebeeckx, P.; Belloni, F.; Berthoumieux, E.; Gunsing, F.; Lampoudis, C.; Calviani, M.; Guerrero, C.; Cano-Ott, D.; Gonzalez Romero, E.; Aïche, M.; Jurado, B.; Mathieu, L.; Derckx, X.; Farget, F.; Rodrigues Tajes, C.; Bacquias, A.; Dessagne, Ph.; Kerveno, M.; Borcea, C.; Negret, A.; Colonna, N.; Goncalves, I.; Penttilä, H.; Rinta-Antila, S.; Kolhinen, V. S.; Jokinen, A.

    2014-05-01

    A significant number of new measurements was undertaken by the ANDES “Measurements for advanced reactor systems” initiative. These new measurements include neutron inelastic scattering from 23Na, Mo, Zr, and 238U, neutron capture cross sections of 238U, 241Am, neutron induced fission cross sections of 240Pu, 242Pu, 241Am, 243Am and 245Cm, and measurements that explore the limits of the surrogate technique. The latter study the feasibility of inferring neutron capture cross sections for Cm isotopes, the neutron-induced fission cross section of 238Pu and fission yields and fission probabilities through full Z and A identification in inverse kinematics for isotopes of Pu, Am, Cm and Cf. Finally, four isotopes are studied which are important to improve predictions for delayed neutron precursors and decay heat by total absorption gamma-ray spectrometry (88Br, 94Rb, 95Rb, 137I). The measurements which are performed at state-of-the-art European facilities have the ambition to achieve the lowest possible uncertainty, and to come as close as is reasonably achievable to the target uncertainties established by sensitivity studies. An overview is presented of the activities and achievements, leaving detailed expositions to the various parties contributing to the conference.

  12. The first ANDES elements: 9-DOF plate bending triangles

    NASA Technical Reports Server (NTRS)

    Militello, Carmelo; Felippa, Carlos A.

    1991-01-01

    New elements are derived to validate and assess the assumed natural deviatoric strain (ANDES) formulation. This is a brand new variant of the assumed natural strain (ANS) formulation of finite elements, which has recently attracted attention as an effective method for constructing high-performance elements for linear and nonlinear analysis. The ANDES formulation is based on an extended parametrized variational principle developed in recent publications. The key concept is that only the deviatoric part of the strains is assumed over the element whereas the mean strain part is discarded in favor of a constant stress assumption. Unlike conventional ANS elements, ANDES elements satisfy the individual element test (a stringent form of the patch test) a priori while retaining the favorable distortion-insensitivity properties of ANS elements. The first application of this formulation is the development of several Kirchhoff plate bending triangular elements with the standard nine degrees of freedom. Linear curvature variations are sampled along the three sides with the corners as gage reading points. These sample values are interpolated over the triangle using three schemes. Two schemes merge back to conventional ANS elements, one being identical to the Discrete Kirchhoff Triangle (DKT), whereas the third one produces two new ANDES elements. Numerical experiments indicate that one of the ANDES element is relatively insensitive to distortion compared to previously derived high-performance plate-bending elements, while retaining accuracy for nondistorted elements.

  13. Viremia in young herons and ibis infected with Venezuelan encephalitis virus.

    PubMed

    Dickerman, R W; Bonacorsa, C M; Scherer, W F

    1976-12-01

    Fifty-seven of 61 nestling, 8- to 30-day-old herons of three species (Black-crowned Night Heron, Great Egret, and Snowy Egret), developed viremia lasting one to three days following subcutaneous inoculation with small doses of endemic or epidemic strains of Venezuelan encephalitis virus from Mexico, Guatemala or Venezuela. Two epidemic strains from Guatemala or Venezuela stimulated levels of viremia similar to those following infection with enzootic strains. Great Egrets, Striated and Boat-billed Herons and Scarlet Ibis older than 30 days of age developed viremias of lower levels and shorter durtions than did young birds. Marked differences in levles of viremia were not observed among Black-crowned Night Herons, Great Egrets, or Snowy Egrets. Over 50% of viremic blood samples from herons 8-30 days of age contained 1000 or more chick embryo cell culture plaque forming units of Venezuelan encephalitis per ml, levels sufficient to infect some vector species mosquitoes.

  14. [Globalization, inequality, and transmission of tropical diseases in the Venezuelan Amazon].

    PubMed

    Botto-Abella, Carlos; Graterol-Mendoza, Beatriz

    2007-01-01

    Economic globalization appears to be causing greater inequalities and increased vulnerability to tropical diseases around the world. The Venezuelan Amazon population, especially the rural indigenous population, displays among the worst health indicators in the Americas. High infant mortality rates in remote indigenous populations indicate that such communities have been affected by the globalization of disease, rather than favored by globalization of health. Globalization has also influenced public policies in the country, affecting the efficiency of control programs targeting tropical diseases. A new global pact for the sustainable development of the planet is needed, supported by the globalization of human values and rights. In Venezuela, new policies for the indigenous health sector, more resources, and greater autonomy could help reduce the inequities described here in the Venezuelan Amazon.

  15. Venezuelan equine encephalitis virus activity in the Gulf Coast region of Mexico, 2003-2010.

    PubMed

    Adams, A Paige; Navarro-Lopez, Roberto; Ramirez-Aguilar, Francisco J; Lopez-Gonzalez, Irene; Leal, Grace; Flores-Mayorga, Jose M; Travassos da Rosa, Amelia P A; Saxton-Shaw, Kali D; Singh, Amber J; Borland, Erin M; Powers, Ann M; Tesh, Robert B; Weaver, Scott C; Estrada-Franco, Jose G

    2012-01-01

    Venezuelan equine encephalitis virus (VEEV) has been the causative agent for sporadic epidemics and equine epizootics throughout the Americas since the 1930s. In 1969, an outbreak of Venezuelan equine encephalitis (VEE) spread rapidly from Guatemala and through the Gulf Coast region of Mexico, reaching Texas in 1971. Since this outbreak, there have been very few studies to determine the northward extent of endemic VEEV in this region. This study reports the findings of serologic surveillance in the Gulf Coast region of Mexico from 2003-2010. Phylogenetic analysis was also performed on viral isolates from this region to determine whether there have been substantial genetic changes in VEEV since the 1960s. Based on the findings of this study, the Gulf Coast lineage of subtype IE VEEV continues to actively circulate in this region of Mexico and appears to be responsible for infection of humans and animals throughout this region, including the northern State of Tamaulipas, which borders Texas.

  16. Venezuelan Equine Encephalitis Virus Activity in the Gulf Coast Region of Mexico, 2003–2010

    PubMed Central

    Adams, A. Paige; Navarro-Lopez, Roberto; Ramirez-Aguilar, Francisco J.; Lopez-Gonzalez, Irene; Leal, Grace; Flores-Mayorga, Jose M.; Travassos da Rosa, Amelia P. A.; Saxton-Shaw, Kali D.; Singh, Amber J.; Borland, Erin M.; Powers, Ann M.; Tesh, Robert B.; Weaver, Scott C.; Estrada-Franco, Jose G.

    2012-01-01

    Venezuelan equine encephalitis virus (VEEV) has been the causative agent for sporadic epidemics and equine epizootics throughout the Americas since the 1930s. In 1969, an outbreak of Venezuelan equine encephalitis (VEE) spread rapidly from Guatemala and through the Gulf Coast region of Mexico, reaching Texas in 1971. Since this outbreak, there have been very few studies to determine the northward extent of endemic VEEV in this region. This study reports the findings of serologic surveillance in the Gulf Coast region of Mexico from 2003–2010. Phylogenetic analysis was also performed on viral isolates from this region to determine whether there have been substantial genetic changes in VEEV since the 1960s. Based on the findings of this study, the Gulf Coast lineage of subtype IE VEEV continues to actively circulate in this region of Mexico and appears to be responsible for infection of humans and animals throughout this region, including the northern State of Tamaulipas, which borders Texas. PMID:23133685

  17. A melting pot of multicontinental mtDNA lineages in admixed Venezuelans.

    PubMed

    Gómez-Carballa, Alberto; Ignacio-Veiga, Ana; Alvarez-Iglesias, Vanesa; Pastoriza-Mourelle, Ana; Ruíz, Yarimar; Pineda, Lennie; Carracedo, Angel; Salas, Antonio

    2012-01-01

    The arrival of Europeans in Colonial and post-Colonial times coupled with the forced introduction of sub-Saharan Africans have dramatically changed the genetic background of Venezuela. The main aim of the present study was to evaluate, through the study of mitochondrial DNA (mtDNA) variation, the extent of admixture and the characterization of the most likely continental ancestral sources of present-day urban Venezuelans. We analyzed two admixed populations that have experienced different demographic histories, namely, Caracas (n = 131) and Pueblo Llano (n = 219). The native American component of admixed Venezuelans accounted for 80% (46% haplogroup [hg] A2, 7% hg B2, 21% hg C1, and 6% hg D1) of all mtDNAs; while the sub-Saharan and European contributions made up ∼10% each, indicating that Trans-Atlantic immigrants have only partially erased the native American nature of Venezuelans. A Bayesian-based model allowed the different contributions of European countries to admixed Venezuelans to be disentangled (Spain: ∼38.4%, Portugal: ∼35.5%, Italy: ∼27.0%), in good agreement with the documented history. Seventeen entire mtDNA genomes were sequenced, which allowed five new native American branches to be discovered. B2j and B2k, are supported by two different haplotypes and control region data, and their coalescence ages are 3.9 k.y. (95% C.I. 0-7.8) and 2.6 k.y. (95% C.I. 0.1-5.2), respectively. The other clades were exclusively observed in Pueblo Llano and they show the fingerprint of strong recent genetic drift coupled with severe historical consanguinity episodes that might explain the high prevalence of certain Mendelian and complex multi-factorial diseases in this region.

  18. Venezuelan Bolivarian Missions in Colombia: What Are the Real, Underlying Reasons for Their Existence?

    DTIC Science & Technology

    2013-06-01

    Guatemala, 40,000 operations in Guyana. Mission Milagro has also treated thousands in Costa Rica, Uruguay, Paraguay and El Salvador , Suriname...Venezuela’s sovereign right to self- determination, or in other words are part of how Venezuela governs itself. This quality is regardless of their... quality of life for Venezuelans, through “the participation of the creative force of the people in the production of goods and services.” Mission

  19. Generation of Constructs for DNA-Directed RNA Interference of Venezuelan Equine Encephalitis Virus Genes

    DTIC Science & Technology

    2006-12-01

    20(Xi-237 Executive summary Introduction: Venezuelan equine encephalitis virus (VEE) is one of a number of different alphaviruses , which can cause...required for replication . It is hypothesized that targeting essential virus genes, either individually or simultaneously, will lead to knockdown or...silencing of the genes, and subsequent inhibition of virus replication . This paper describes the PCR-based approach used to generate DNA cassettes that

  20. Accuracy of dental age estimation in Venezuelan children: comparison of Demirjian and Willems methods.

    PubMed

    Medina, Aída C; Blanco, Lucila

    2014-01-01

    Dental age is a somatic maturity indicator with importance in clinical and forensic dentistry. The purpose of this study is to compare the applicability of the Demirjian and Willems methods for dental age estimation in a group of Venezuelan children. Panoramic radiographs of 238 Venezuelan children aged 5-13 years were used to assess dental age using the methods described by Demirjian and Willems. Children with unclear panoramic radiographs, dental agenesis, and premature loss of primary teeth were excluded. Mean differences between dental age and chronological age by gender and age groups were estimated (ANOVA, Student tests p = 0.05). For the Demirjian method, the mean difference between dental age and chronological age was 0.62 +/- 0.93 years, statistically significant. The mean overestimation was lower for females than for males (females 0.56 +/- 0.96 years, males 0.67 +/- 0.93 years). For the Willems method, the mean difference between dental age and chronological age was 0.15 +/- 0.97 years, not statistically significant. Accuracy was significantly different between genders, performing best for females (females 0.01 +/- 0.96 years, males 0.29 +/- 0.96 years). The Willems method for age estimation was found to be more accurate than the Demirjian method in this sample of Venezuelan children.

  1. Placental and fetal alterations due to Venezuelan equine encephalitis virus in rats.

    PubMed Central

    García-Tamayo, J; Esparza, J; Martínez, A J

    1981-01-01

    Histopathological changes in the placentas, embryos, and fetuses of rats inoculated intraperitoneally with the virulent Guajira strain of Venezuelan equine encephalitis virus were studied by light microscopy and immunoperoxidase methods. Rats inoculated before day 15 of pregnancy showed necrosis and hemorrhages in the embryonic disks. Swelling of cytoplasm and nuclear pyknosis of cyto- and syncytotrophoblastic cells were noted as early as 2 days after inoculation. During weeks 1 and 2 of pregnancy, death of the embryos was always observed 3 to 4 days after Venezuelan equine encephalitis virus inoculation. Placental and fetal damage varied among the specimens. In rats 18 days pregnant and sacrificed 2 days after inoculation, there were some viable fetuses; the placentas showed inflammatory reactions in the mesometrial and decidual vessels. Other rats sacrificed at 3 to 4 days after inoculation showed large placental infarcts with fetal death. Viremia peaked during day 2 after inoculation. Immunoperoxidase stains demonstrated viral antigens present in the decidua, myometrium, and cyto- and syncytotrophoblastic cells. These experiments provide additional data regarding the pathogenesis and structural damage in the placental and fetal tissues caused by Venezuelan equine encephalitis virus. Images PMID:7251148

  2. Late Pleistocene and Holocene Hydroclimate Variability in the Tropical Andes from Alpine Lake Sediments, Cordillera de Mérida, Venezuela

    NASA Astrophysics Data System (ADS)

    Larsen, D. J.; Abbott, M. B.; Polissar, P. J.

    2014-12-01

    The tropics play a major role in the global hydrologic cycle and changes to tropical rainfall patterns have critical implications for water resources and ecosystem dynamics over large geographic scales. In tropical South America, late Pleistocene and Holocene precipitation variability has been documented in geologic records and associated with numerous external and internal variables, including changes in summer insolation, South American summer monsoon strength, Pacific Ocean sea surface temperatures, continental moisture recycling, and other climate processes. However, there are few records from the northern hemisphere tropical Americas, a key region for understanding interhemispheric linkages and the drivers of tropical hydroclimate variability. Here, we present a ~13 ka record of coupled hydroclimate and environmental changes from Laguna Brava, a small (~0.07 km2), hydrologically closed lake basin situated at 2400 m asl in the Cordillera de Mérida, Venezuela. Sediment cores collected from varying water depths and proximity to shore are placed in a chronologic framework using radiocarbon ages from terrestrial macrofossils, and analyzed for a suite of physical, bulk geochemical, and stable isotopic parameters. Compound specific hydrogen isotope (D/H) measurements of terrestrial plant waxes (long-chain n-alkanes) show a sharp increase in the late Pleistocene, followed by a long-term trend toward more negative values that suggest a ~20‰ decrease in the D/H ratios of South American tropical precipitation during the Holocene. This pattern is consistent in sign and magnitude to other South American precipitation reconstructions from both hemispheres, indicating interhemispheric similarities in tropical hydroclimate variability. Superimposed on this continent-scale trend are changes in moisture balance and environmental conditions in the Venezuelan Andes. We reconstruct these parameters at Laguna Brava at multidecadal and centennial resolution and evaluate this

  3. The presence-absence situation and its impact on the assemblage structure and interspecific relations of Pronophilina butterflies in the Venezuelan Andes (Lepidoptera: Nymphalidae).

    PubMed

    Pyrcz, T W; Garlacz, R

    2012-06-01

    Assemblage structure and altitudinal patterns of Pronophilina, a species-rich group of Andean butterflies, are compared in El Baho and Monte Zerpa, two closely situated and ecologically similar Andean localities. Their faunas differ only by the absence of Pedaliodes ornata Grose-Smith in El Baho. There are, however, important structural differences between the two Pronophilina assemblages. Whereas there are five co-dominant species in Monte Zerpa, including P. ornata, Pedaliodes minabilis Pyrcz is the only dominant with more than half of all the individuals in the sample in El Baho. The absence of P. ornata in El Baho is investigated from historical, geographic, and ecological perspectives exploring the factors responsible for its possible extinction including climate change, mass dying out of host plants, and competitive exclusion. Although competitive exclusion between P. ornata and P. minabilis is a plausible mechanism, considered that their ecological niches overlap, which suggests a limiting influence on each other's populations, the object of competition was not identified, and the reason of the absence of P. ornata in El Baho could not be established. The role of spatial interference related to imperfect sexual behavioral isolation is evaluated in maintaining the parapatric altitudinal distributions of three pairs of phenotypically similar and related species of Pedaliodes, Corades, and Lymanopoda.

  4. Vector Competence of Peruvian Mosquitoes (Diptera:Culicidae) for a Subtype IIIC Strain in the Venezuelan Equine Encephalomyelitis Complex Isolated from Mosquitoes Captured in Peru

    DTIC Science & Technology

    2006-03-01

    strains of Venezuelan equine encephalitis virus. J Am Mosq Control Assoc 15:295–298. Turell MJ, Gargan TP II, Bailey CL. 1984. Replication and dissemination...Venezuelan equine encephalitis (VEE) complex alphavirus by Culex (Melanoconion) gnomatos (Diptera: Culicidae) in northeastern Peru. J Med Entomol 42:404–408

  5. Reflections on Andes' Goal-Free User Interface

    ERIC Educational Resources Information Center

    VanLehn, Kurt

    2016-01-01

    Although the Andes project produced many results over its 18 years of activity, this commentary focuses on its contributions to understanding how a goal-free user interface impacts the overall design and performance of a step-based tutoring system. Whereas a goal-aligned user interface displays relevant goals as blank boxes or empty locations that…

  6. Andes Hantavirus Variant in Rodents, Southern Amazon Basin, Peru

    PubMed Central

    Tokarz, Rafal; Ghersi, Bruno M.; Salmon-Mulanovich, Gabriela; Guezala, M. Claudia; Albujar, Christian; Mendoza, A. Patricia; Tinoco, Yeny O.; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T.; Hirschberg, David L.; Lipkin, W. Ian; Bausch, Daniel G.; Montgomery, Joel M.

    2014-01-01

    We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted. PMID:24447689

  7. Andes hantavirus variant in rodents, southern Amazon Basin, Peru.

    PubMed

    Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M; Salmon-Mulanovich, Gabriela; Guezala, M Claudia; Albujar, Christian; Mendoza, A Patricia; Tinoco, Yeny O; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T; Hirschberg, David L; Lipkin, W Ian; Bausch, Daniel G; Montgomery, Joel M

    2014-02-01

    We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

  8. Stable oxygen isotopes (delta18(O)) in Austrocedrus chilensis tree rings reflect climate variability in northwestern Patagonia, Argentina.

    PubMed

    Roig, F A; Siegwolf, R; Boninsegna, J A

    2006-11-01

    The stable oxygen isotope (delta (18)O) composition of Austrocedrus chilensis (D. Don) Endl. (Cupressaceae) tree rings potentially provide retrospective views of changes in environment and climate in the semi-arid lands of Patagonia. We report the development of the first annually resolved delta (18)O tree-ring chronology obtained from natural forests of the foothills of the northwestern Patagonian Andes. The isotope record spans between 1890 and 1994 AD. We explore the probable links between this record and the climate of the region. Air temperatures during summer conditions are significantly, but not strongly, inversely correlated with annual delta (18)O values from Austrocedrus tree rings. The strongest correlations are between the southern oscillation index (SOI) and the tree rings. The existence of millennial-age Austrocedrus trees in northern Patagonia provides interesting possibilities for examining these climate-related isotopic signals over most of the last 1,000 years.

  9. Forensic analysis of Venezuelan elections during the Chávez presidency.

    PubMed

    Jiménez, Raúl; Hidalgo, Manuel

    2014-01-01

    Hugo Chávez dominated the Venezuelan electoral landscape since his first presidential victory in 1998 until his death in 2013. Nobody doubts that he always received considerable voter support in the numerous elections held during his mandate. However, the integrity of the electoral system has come into question since the 2004 Presidential Recall Referendum. From then on, different sectors of society have systematically alleged electoral irregularities or biases in favor of the incumbent party. We have carried out a thorough forensic analysis of the national-level Venezuelan electoral processes held during the 1998-2012 period to assess these complaints. The second-digit Benford's law and two statistical models of vote distributions, recently introduced in the literature, are reviewed and used in our case study. In addition, we discuss a new method to detect irregular variations in the electoral roll. The outputs obtained from these election forensic tools are examined taking into account the substantive context of the elections and referenda under study. Thus, we reach two main conclusions. Firstly, all the tools uncover anomalous statistical patterns, which are consistent with election fraud from 2004 onwards. Although our results are not a concluding proof of fraud, they signal the Recall Referendum as a turning point in the integrity of the Venezuelan elections. Secondly, our analysis calls into question the reliability of the electoral register since 2004. In particular, we found irregular variations in the electoral roll that were decisive in winning the 50% majority in the 2004 Referendum and in the 2012 Presidential Elections.

  10. Isonymy structure of Sucre and Táchira, two Venezuelan states.

    PubMed

    Rodríguez-Larralde, A; Barrai, I

    1997-10-01

    The isonymy structure of two Venezuelan states, Sucre and Táchira, is described using the surnames of the Register of Electors updated in 1991. The frequency distribution of surnames pooled together by sex was obtained for the 57 counties of Sucre and the 52 counties of Táchira, based on total population sizes of 158,705 and 160,690 individuals, respectively. The coefficient of consanguinity resulting from random isonymy (phi ii), Karlin and McGregor's ni (identical to v), and the proportion of the population included in surnames represented only once (estimator A) and in the seven most frequent surnames (estimator B) were calculated for each county. RST, a measure of microdifferentiation, was estimated for each state. The Euclidean distance between pairs of counties within states was calculated together with the corresponding geographic distances. The correlations between their logarithmic transformations were significant in both cases, indicating differentiation of surnames by distance. Dendrograms based on the Euclidean distance matrix were constructed. From them a first approximation of the effect of internal migration within states was obtained. Ninety-six percent of the coefficient of consanguinity resulting from random isonymy is determined by the proportion of the population included in the seven most frequent surnames, whereas between 72% and 88% of Karlin and McGregor's ni for Sucre and Táchira, respectively, is determined by the proportion of population included in surnames represented only once. Surnames with generalized and with focal distribution were identified for both states, to be used as possible indicators of the geographic origin of their carriers. Our results indicate that Táchira's counties, on average, tend to be more isolated than Sucre's counties, as measured by RST, estimator B, and phi ii. Comparisons with the results obtained for other. Venezuelan states and other non-Venezuelan populations are also given.

  11. Forensic Analysis of Venezuelan Elections during the Chávez Presidency

    PubMed Central

    Jiménez, Raúl; Hidalgo, Manuel

    2014-01-01

    Hugo Chávez dominated the Venezuelan electoral landscape since his first presidential victory in 1998 until his death in 2013. Nobody doubts that he always received considerable voter support in the numerous elections held during his mandate. However, the integrity of the electoral system has come into question since the 2004 Presidential Recall Referendum. From then on, different sectors of society have systematically alleged electoral irregularities or biases in favor of the incumbent party. We have carried out a thorough forensic analysis of the national-level Venezuelan electoral processes held during the 1998–2012 period to assess these complaints. The second-digit Benford's law and two statistical models of vote distributions, recently introduced in the literature, are reviewed and used in our case study. In addition, we discuss a new method to detect irregular variations in the electoral roll. The outputs obtained from these election forensic tools are examined taking into account the substantive context of the elections and referenda under study. Thus, we reach two main conclusions. Firstly, all the tools uncover anomalous statistical patterns, which are consistent with election fraud from 2004 onwards. Although our results are not a concluding proof of fraud, they signal the Recall Referendum as a turning point in the integrity of the Venezuelan elections. Secondly, our analysis calls into question the reliability of the electoral register since 2004. In particular, we found irregular variations in the electoral roll that were decisive in winning the 50% majority in the 2004 Referendum and in the 2012 Presidential Elections. PMID:24971462

  12. Thermophilization of adult and juvenile tree communities in the northern tropical Andes

    PubMed Central

    Duque, Alvaro; Stevenson, Pablo R.; Feeley, Kenneth J.

    2015-01-01

    Climate change is expected to cause shifts in the composition of tropical montane forests towards increased relative abundances of species whose ranges were previously centered at lower, hotter elevations. To investigate this process of “thermophilization,” we analyzed patterns of compositional change over the last decade using recensus data from a network of 16 adult and juvenile tree plots in the tropical forests of northern Andes Mountains and adjacent lowlands in northwestern Colombia. Analyses show evidence that tree species composition is strongly linked to temperature and that composition is changing directionally through time, potentially in response to climate change and increasing temperatures. Mean rates of thermophilization [thermal migration rate (TMR), °C⋅y−1] across all censuses were 0.011 °C⋅y−1 (95% confidence interval = 0.002–0.022 °C⋅y−1) for adult trees and 0.027 °C⋅y−1 (95% confidence interval = 0.009–0.050 °C⋅y−1) for juvenile trees. The fact that thermophilization is occurring in both the adult and juvenile trees and at rates consistent with concurrent warming supports the hypothesis that the observed compositional changes are part of a long-term process, such as global warming, and are not a response to any single episodic event. The observed changes in composition were driven primarily by patterns of tree mortality, indicating that the changes in composition are mostly via range retractions, rather than range shifts or expansions. These results all indicate that tropical forests are being strongly affected by climate change and suggest that many species will be at elevated risk for extinction as warming continues. PMID:26261350

  13. Laboratory Transmission of Venezuelan Equine Encephalomyelitis Virus by the Tick Hyalomma Truncatum

    DTIC Science & Technology

    1994-01-01

    equine On day 21 after infestation of the first guinea-pig, none encephalomyelitis virus by the tick of 95 unfed nv mphs sampled contained virus...Epi/ootic strains oft Venezuelan equine encephalo- nymphs [minimum infection rate =2 200 1% I"( 1 contained inveliti. \\EE’ virus Alp/tavirus. family...Togaviridae virus mean titre= 102 1 1PFU ’. About 200 unfed nymphs ý:iuse serious disease tin horse % and humans throughout were placed on a guinea-pig at

  14. CD4+ T cells provide protection against acute lethal encephalitis caused by Venezuelan equine encephalitis virus.

    PubMed

    Yun, Nadezhda E; Peng, Bi-Hung; Bertke, Andrea S; Borisevich, Viktoriya; Smith, Jennifer K; Smith, Jeanon N; Poussard, Allison L; Salazar, Milagros; Judy, Barbara M; Zacks, Michele A; Estes, D Mark; Paessler, Slobodan

    2009-06-19

    Studying the mechanisms of host survival resulting from viral encephalitis is critical to the development of vaccines. Here we have shown in several independent studies that high dose treatment with neutralizing antibody prior to intranasal infection with Venezuelan equine encephalitis virus had an antiviral effect in the visceral organs and prolonged survival time of infected mice, even in the absence of alphabeta T cells. Nevertheless, antibody treatment did not prevent the development of lethal encephalitis. On the contrary, the adoptive transfer of primed CD4(+) T cells was necessary to prevent lethal encephalitis in mice lacking alphabeta T cell receptor.

  15. [The vaccines based on the replicon of the venezuelan equine encephalomyelitis virus against viral hemorrhagic fevers].

    PubMed

    Petrov, A A; Plekhanova, T M; Sidorova, O N; Borisevich, S V; Makhlay, A A

    2015-01-01

    The status of the various recombinant DNA and RNA-derived candidate vaccines, as well as the Venezuelan equine encephalomyelitis virus (VEEV) replicon vaccine system against extremely hazardous viral hemorrhagic fevers, were reviewed. The VEEV-based replication-incompetent vectors offer attractive features in terms of safety, high expression levels of the heterologous viral antigen, tropism to dendritic cells, robust immune responses, protection efficacy, low potential for pre-existing anti-vector immunity and possibility of engineering multivalent vaccines were tested. These features of the VEEV replicon system hold much promise for the development of new generation vaccine candidates against viral hemorrhagic fevers.

  16. Synchronous interhemispheric Holocene climate trends in the tropical Andes.

    PubMed

    Polissar, Pratigya J; Abbott, Mark B; Wolfe, Alexander P; Vuille, Mathias; Bezada, Maximiliano

    2013-09-03

    Holocene variations of tropical moisture balance have been ascribed to orbitally forced changes in solar insolation. If this model is correct, millennial-scale climate evolution should be antiphased between the northern and southern hemispheres, producing humid intervals in one hemisphere matched to aridity in the other. Here we show that Holocene climate trends were largely synchronous and in the same direction in the northern and southern hemisphere outer-tropical Andes, providing little support for the dominant role of insolation forcing in these regions. Today, sea-surface temperatures in the equatorial Pacific Ocean modulate rainfall variability in the outer tropical Andes of both hemispheres, and we suggest that this mechanism was pervasive throughout the Holocene. Our findings imply that oceanic forcing plays a larger role in regional South American climate than previously suspected, and that Pacific sea-surface temperatures have the capacity to induce abrupt and sustained shifts in Andean climate.

  17. Synchronous interhemispheric Holocene climate trends in the tropical Andes

    PubMed Central

    Polissar, Pratigya J.; Abbott, Mark B.; Wolfe, Alexander P.; Vuille, Mathias; Bezada, Maximiliano

    2013-01-01

    Holocene variations of tropical moisture balance have been ascribed to orbitally forced changes in solar insolation. If this model is correct, millennial-scale climate evolution should be antiphased between the northern and southern hemispheres, producing humid intervals in one hemisphere matched to aridity in the other. Here we show that Holocene climate trends were largely synchronous and in the same direction in the northern and southern hemisphere outer-tropical Andes, providing little support for the dominant role of insolation forcing in these regions. Today, sea-surface temperatures in the equatorial Pacific Ocean modulate rainfall variability in the outer tropical Andes of both hemispheres, and we suggest that this mechanism was pervasive throughout the Holocene. Our findings imply that oceanic forcing plays a larger role in regional South American climate than previously suspected, and that Pacific sea-surface temperatures have the capacity to induce abrupt and sustained shifts in Andean climate. PMID:23959896

  18. Glacier shrinkage and water resources in the Andes

    NASA Astrophysics Data System (ADS)

    Francou, Bernard; Coudrain, Anne

    For more than a century glaciers around the world have been melting as air temperatures rise due to a combination of natural processes and human activity. The disappearance of these glaciers can have wide-ranging effects, such as the creation of new natural hazards or changes in stream flow that could threaten water suppliesSome of the most dramatic melting has occurred in the Andes mountain range in South America. To highlight the climatic and glacial change in the Andes and to encourage the scientific community to strengthen the glacier observation network that stretches from Colombia to the Patagonian ice fields, the Instituto Nacional de Recursos Naturales (INRENA), Perú, and the Institute of Research and Development (IRD), France, recently organized the second Symposium on Mass Balance of Andean Glaciers in Huaráz,Perú.

  19. Crustal-thickness variations in the central Andes

    NASA Astrophysics Data System (ADS)

    Beck, Susan L.; Zandt, George; Myers, Stephen C.; Wallace, Terry C.; Silver, Paul G.; Drake, Lawrence

    1996-05-01

    We estimated the crustal thickness along an east-west transect across the Andes at lat 20°S and along a north-south transect along the eastern edge of the Altiplano from data recorded on two arrays of portable broadband seismic stations (BANJO and SEDA). Waveforms of deep regional events in the downgoing Nazca slab and teleseismic earthquakes were processed to isolate the P-to-S converted phases from the Moho in order to compute the crustal thickness. We found crustal-thickness variations of nearly 40 km across the Andes. Maximum crustal thicknesses of 70 74 km under the Western Cordillera and the Eastern Cordillera thin to 32 38 km 200 km east of the Andes in the Chaco Plain. The central Altiplano at 20°S has crustal thicknesses of 60 to 65 km. The crust also appears to thicken from north (16°S, 55 60 km) to south (20°S, 70 74 km) along the Eastern Cordillera. The Subandean zone crust has intermediate thicknesses of 43 to 47 km. Crustal-thickness predictions for the Andes based on Airy-type isostatic behavior show remarkable overall correlation with observed crustal thickness in the regions of high elevation. In contrast, at the boundary between the Eastern Cordillera and the Subandean zone and in the Chaco Plain, the crust is thinner than predicted, suggesting that the crust in these regions is supported in part by the flexural rigidity of a strong lithosphere. With additional constraints, we conclude that the observation of Airy-type isostasy is consistent with thickening associated with compressional shortening of a weak lithosphere squeezed between the stronger lithosphere of the subducting Nazca plate and the cratonic lithosphere of the Brazilian craton.

  20. Synthetic Seismogram Study of the Eastern Central Andes

    DTIC Science & Technology

    2008-09-30

    gaps located in the coupling zone of the Nazca and the South American plates. The above-mentioned earthquakes were here used to generate the...the limits of gaps located in the coupling zone of the Nazca and the South American plates. The above-mentioned earthquakes were here used to generate...surrounding areas. RESEARCH PERFORMED The area of study is located in the Eastern Central Andes, in the region where the Nazca Plate subducts at 300

  1. Crustal-thickness variations in the central Andes

    SciTech Connect

    Beck, S.L.; Myers, S.C.; Wallace, T.C.; Zandt, G. |; Silver, P.G.; Drake, L.

    1996-05-01

    We estimated the crustal thickness along an east-west transect across the Andes at lat 20{degree}S and along a north-south transect along the eastern edge of the Altiplano from data recorded on two arrays of portable broadband seismic stations (BANJO and SEDA). We found crustal-thickness variations of nearly 40 km across the Andes. Maximum crustal thicknesses of 70-74 km under the Western Cordillera and the Eastern Cordillera thin to 32-38 km 200 km east of the Andes in the Chaco Plain. The central Altiplano at 20{degree}S has crustal thicknesses of 60 to 65 km. The crust also appears to thicken from north (16{degree}S, 55-60 km) to south (20{degree}S, 70-74 km) along the Eastern Cordillera. The Subandean zone crust has intermediate thicknesses of 43 to 47 km. Crustal-thickness predictions for the Andes based on Airy-type isostatic behavior show remarkable overall correlation with observed crustal thickness in the regions of high elevation. In contrast, at the boundary between the Eastern Cordillera and the Subandean zone and in the Chaco Plain, the crust is thinner than predicted, suggesting that the crust in these regions is supported in part by the flexural rigidity of a strong lithosphere. With additional constraints, we conclude that the observation of Airy-type isostasy is consistent with thickening associated with compressional shortening of a weak lithosphere squeezed between the stronger lithosphere of the subducting Nazca plate and the cratonic lithosphere of the Brazilian craton. 26 refs., 4 figs.

  2. EFFECT OF ADJUVANTS ON ANTIBODY RESPONSE OF RABBITS INOCULATED WITH VENEZUELAN EQUINE ENCEPHALOMYELITIS VIRUS

    PubMed Central

    Shepel, Michael; Klugerman, Maxwell R.

    1963-01-01

    Shepel, Michael (U.S. Army Biological Laboratories, Fort Detrick, Frederick, Md.) and Maxwell R. Klugerman. Effect of adjuvants on antibody response of rabbits inoculated with Venezuelan equine encephalomyelitis virus. J. Bacteriol. 85:1150–1155. 1963.—Hemagglutination-inhibition, neutralization, and complement-fixation tests were performed on sera of rabbits inoculated with Venezuelan equine encephalomyelitis (VEE) virus in combination with Freund's adjuvants and in Hank's salt solution. This study indicated that the complete adjuvants (i.e., with mycobacteria) considerably increased the antibody response to VEE virus. Mycobacterium butyricum (M. smegmatis) appeared to be more effective than M. tuberculosis H37Ra. In the absence of mycobacteria, the response was much less pronounced. Paper electrophoretic studies of the antisera demonstrated a marked increase in gamma-globulin production, an increase in the beta-globulin, and an increase in total protein as the result of adding VEE virus to the complete adjuvants. A decrease in the albumin fraction appeared to be caused by the complete adjuvants rather than by the VEE virus itself. The incomplete adjuvant (without mycobacteria) plus virus contributed little, if any, stimulation toward the production of gamma-globulin, nor did it appear to affect the serum-albumin levels. Images PMID:14044008

  3. Genetic diversity and relationships among Venezuelan equine encephalitis virus field isolates from Colombia and Venezuela.

    PubMed

    Moncayo, A C; Medina, G M; Kalvatchev, Z; Brault, A C; Barrera, R; Boshell, J; Ferro, C; Freier, J E; Navarro, J C; Salas, R; De Siger, J; Vasquez, C; Walder, R; Weaver, S C

    2001-12-01

    During field studies of enzootic Venezuelan equine encephalitis (VEE) viruses associated with epizootic emergence, a large number of virus isolates were made in sylvatic foci of Venezuela and Colombia. To rapidly characterize these isolates, antigenic subtypes were determined by means of immunofluorescence and by single-strand conformational polymorphism (SSCP) analysis by use of an 856-bp fragment from the P62 gene, which we used to distinguish genetic variants. Representative isolates were sequenced to assess the sensitivity of SSCP to detect genetic differences. The SSCP analysis distinguished isolates differing by as little as 1 nucleotide; overall, differences of > or = 1 nucleotide were recognized 89% of the time, and the sensitivity to distinguish strains that differed by only 1 or 4 nucleotides was 17 and 57%, respectively. Phylogenetic analyses of representative sequences showed that all recent isolates from the Catatumbo region of western Venezuela and the middle Magdalena Valley of Colombia were closely related to epizootic subtype IAB and IC strains; strains from Yaracuy and Miranda States were more distantly related. Cocirculation of the same virus genotype in both Colombian and Venezuelan foci indicated that these viruses are readily transported between enzootic regions separated by > 300 km. The SSCP analysis appears to be a simple, fast, and relatively efficient method of screening VEE virus isolates to identify meaningful genetic variants.

  4. Analysis of the CFTR gene in Venezuelan cystic fibrosis patients, identification of six novel cystic fibrosis-causing genetic variants.

    PubMed

    Sánchez, Karen; de Mendonca, Elizabeth; Matute, Xiorama; Chaustre, Ismenia; Villalón, Marlene; Takiff, Howard

    2016-01-01

    The mutations in the CFTR gene found in patients with cystic fibrosis (CF) have geographic differences, but there are scant data on their prevalence in Venezuelan patients. This study determined the frequency of common CFTR gene mutations in a group of Venezuelan patients with CF. The 27 exons of the CFTR gene from 110 Venezuelan patients in the National CF Program were amplified and sequenced. A total of 36 different mutations were identified, seven with frequencies greater than 1%: p.Phe508del (27.27%), p.Gly542* (3.18%), c.2988+1G>A (3.18%), p.Arg334Trp (1.36%), p.Arg1162* (1.36%), c.1-8G>C (1.36%), and p.[Gly628Arg;Ser1235Arg](1.36). In 40% of patients, all with a clinical diagnosis of CF, no mutations were found. This report represents the largest cohort of Venezuelan patients with CF ever examined, and includes a wider mutation panel than has been previously studied in this population. Mutations common in Southern European populations predominate, and several new mutations were discovered, but no mutations were found in 40% of the cohort.

  5. Analysis of the CFTR gene in Venezuelan cystic fibrosis patients, identification of six novel cystic fibrosis-causing genetic variants

    PubMed Central

    Sánchez, Karen; de Mendonca, Elizabeth; Matute, Xiorama; Chaustre, Ismenia; Villalón, Marlene; Takiff, Howard

    2016-01-01

    The mutations in the CFTR gene found in patients with cystic fibrosis (CF) have geographic differences, but there are scant data on their prevalence in Venezuelan patients. This study determined the frequency of common CFTR gene mutations in a group of Venezuelan patients with CF. The 27 exons of the CFTR gene from 110 Venezuelan patients in the National CF Program were amplified and sequenced. A total of 36 different mutations were identified, seven with frequencies greater than 1%: p.Phe508del (27.27%), p.Gly542* (3.18%), c.2988+1G>A (3.18%), p.Arg334Trp (1.36%), p.Arg1162* (1.36%), c.1-8G>C (1.36%), and p.[Gly628Arg;Ser1235Arg](1.36). In 40% of patients, all with a clinical diagnosis of CF, no mutations were found. This report represents the largest cohort of Venezuelan patients with CF ever examined, and includes a wider mutation panel than has been previously studied in this population. Mutations common in Southern European populations predominate, and several new mutations were discovered, but no mutations were found in 40% of the cohort. PMID:27022295

  6. Amplified warming at high elevation in the tropical Andes? (Invited)

    NASA Astrophysics Data System (ADS)

    Vuille, M. F.; Buytaert, W.; Zulkafli, Z.; Franquist, E.

    2013-12-01

    Theoretical and modeling studies suggest that adjustment of the moist-adiabatic lapse rate due to continued greenhouse gas radiative forcing will lead to accelerated warming of tropical high-elevation mountain regions in the 21st century. The scarcity of observational data at high-elevation sites in the tropics, however, has complicated the unambiguous detection and potential attribution of such a warming signal. Here we will focus on the tropical Andes, where such an enhanced warming is of special concern, given the important ecosystem services provided by wetlands and glaciers, both being very sensitive to enhanced warming and resulting changes in evaporation, melt rates, snow-rain ratios, etc. This presentation will review the potential of various feedbacks, such as snow-albedo feedback, water vapor feedback, lapse rate feedback and others to produce differential warming rates at different elevations in the Andes. These theoretical considerations will then be compared with the latest available observational and modeling results regarding evidence (or lack thereof) for enhanced warming at high elevation sites. Our analysis relies on an updated database of more than 850 stations from different elevations along the Andes, complemented by projections for several representative concentration pathways (RCP's) from the CMIP5 multi-model ensemble.

  7. Multiagent Vaccines Vectored by Venezuelan Equine Encephalitis Virus Replicon Elicits Immune Responses to Marburg Virus and Protection Against Anthrax and Botulinum Neurotoxin in Mice

    DTIC Science & Technology

    2006-01-01

    formulations of individual Venezuelan equine encephalitis (VEE) virus replicon- vectored vaccines against a bacterial disease, anthrax; a viral disease...here the results of using formulations of individual Venezuelan equine encephalitis (VEE) virus replicon-vectored vaccines against a bacterial disease...on days 0, 35, and 70 with the indicated vaccines. Ne b Infectious units were used to measure VRP and milliliters were used to measur c The

  8. Is tourism damaging ecosystems in the Andes? Current knowledge and an agenda for future research.

    PubMed

    Barros, Agustina; Monz, Christopher; Pickering, Catherine

    2015-03-01

    Despite the popularity of tourism and recreation in the Andes in South America and the regions conservation value, there is limited research on the ecological impacts of these types of anthropogenic use. Using a systematic quantitative literature review method, we found 47 recreation ecology studies from the Andes, 25 of which used an experimental design. Most of these were from the Southern Andes in Argentina (13 studies) or Chile (eight studies) with only four studies from the Northern Andes. These studies documented a range of impacts on vegetation, birds and mammals; including changes in plant species richness, composition and vegetation cover and the tolerance of wildlife of visitor use. There was little research on the impacts of visitors on soils and aquatic systems and for some ecoregions in the Andes. We identify research priorities across the region that will enhance management strategies to minimise visitor impacts in Andean ecosystems.

  9. Natural enzootic vectors of Venezuelan equine encephalitis virus, Magdalena Valley, Colombia.

    PubMed

    Ferro, Cristina; Boshell, Jorge; Moncayo, Abelardo C; Gonzalez, Marta; Ahumada, Marta L; Kang, Wenli; Weaver, Scott C

    2003-01-01

    To characterize the transmission cycle of enzootic Venezuelan equine encephalitis virus (VEEV) strains believed to represent an epizootic progenitor, we identified natural vectors in a sylvatic focus in the middle Magdalena Valley of Colombia. Hamster-baited traps were placed into an active forest focus, and mosquitoes collected from each trap in which a hamster became infected were sorted by species and assayed for virus. In 18 cases, a single, initial, high-titered mosquito pool representing the vector species was identified. These vectors included Culex (Melanoconion) vomerifer (11 transmission events), Cx. (Mel.) pedroi (5 transmissions) and Cx. (Mel.) adamesi (2 transmissions). These results extend the number of proven enzootic VEEV vectors to 7, all of which are members of the Spissipes section of the subgenus Melanoconion. Our findings contrast with previous studies, which have indicated that a single species usually serves as the principal enzootic VEEV vector at a given location.

  10. Chikungunya fever: Atypical and lethal cases in the Western hemisphere: A Venezuelan experience.

    PubMed

    Torres, Jaime R; Leopoldo Códova G; Castro, Julio S; Rodríguez, Libsen; Saravia, Víctor; Arvelaez, Joanne; Ríos-Fabra, Antonio; Longhi, María A; Marcano, Melania

    2015-01-01

    A large epidemic of Chikungunya fever currently affects the Caribbean, Central and South America. Despite a high number of reported cases, little is known on the occurrence of severe clinical complications. We describe four Venezuelan patients with a severe and/or lethal course who exhibit unusual manifestations of the disease. Case 1 describes a 75 year-old man with rapid onset of septic shock and multi-organ failure. Cases 2 and 3 describe two patients with rapid aggressive clinical course who developed shock, severe purpuric lesions and a distinct area large of necrosis in the nasal region. Case 4 depicts a splenectomized woman with shock, generalized purpuric lesions, bullous dermatosis and acronecrosis of an upper limb. Chikungunya fever in the Western hemisphere may also associate with atypical and severe manifestations. Some patients experience a life-threatening, aggressive clinical course, with rapid deterioration and death due to multisystem failure.

  11. NRAMP1 and VDR Gene Polymorphisms in Susceptibility to Tuberculosis in Venezuelan Population

    PubMed Central

    Fernández-Mestre, Mercedes; Villasmil, Ángel; Takiff, Howard; Fuentes Alcalá, Zhenia

    2015-01-01

    Natural resistance-associated macrophage protein (Nramp1) and the vitamin D receptor (VDR) are central components of the innate and adaptive immunity against Mycobacterium tuberculosis, and associations between susceptibility to tuberculosis and polymorphisms in the genes NRAMP and VDR have been sought in geographically diverse populations. We investigated associations of NRAMP1 and VDR gene polymorphisms with susceptibility to TB in the Venezuelan population. The results suggest the absence of any association between VDR variants FokI, ApaI, and TaqI and susceptibility to tuberculosis. In contrast, the NRAMP1 3′UTR variants were associated with susceptibility to M. tuberculosis infection, as seen in the comparisons between TST+ and TST− controls, and also with progression to TB disease, as shown in the comparisons between TB patients and TST+ controls. This study confirms the previously described association of the NRAMP1 3′UTR polymorphism with M. tuberculosis infection and disease progression. PMID:26578819

  12. The Rey Auditory Verbal Learning Test: normative data developed for the Venezuelan population.

    PubMed

    Ferreira Correia, Aline; Campagna Osorio, Ilva

    2014-03-01

    The Rey Auditory Verbal Learning Test (RAVLT) is a neuropsychological tool widely used to assess functions such as attention, memory, and learning ability in the auditory-verbal domain. Norms for the test have been developed in many different languages and they show different relationships with demographic variables. The main objective of this research was to develop specific norms for the Venezuelan population, with particular focus on the influences of age, education, gender, and socioeconomic status. A Spanish version of the test was administered to a quota sample of 629 healthy adults. Pearson's correlation analysis (p < .001) showed a significant association between RAVLT performance and age (r = -.401), education (r = .386), and socioeconomic status (r = -.196), but not between RAVLT performance and gender (r = -.054). Due to the strength of the correlations, only age and education were considered in the development of final norms.

  13. Primary immunoglobulin response of herons to infection with Venezuelan encephalitis virus.

    PubMed Central

    Powers, C D; Dickerman, R W

    1975-01-01

    Seven to nine days after inoculation with a replicating antigen, Venezuelan encephalitis virus, hemagglutination-inhibiting antibodies were present in plasma of 18 to 20 black-crowned night herons (BCNH), 14 of 15 great egrets (ge) , and 7 of 7 snowy egrets (SE). 19S (immunoglobulin M) precedes 7S (immunoglobulin G) antibodies in all but one bird of six GE, six SE, and six BCNH. 19S antibodies were detected for only 2 to 4 weeks post-inoculation. The induction period for both types of antibody was prolonged by 2 to 6 days as compared with earlier studies in gallinaceous birds using nonreplicating antigens. A marked delay in reaching peak titer of 7S antibodies was also observed. Hemagglutination inhibition tests were nearly as sensitive as neutralization tests for detecting 19S and early 7S antibodies. Size of virus inoculum did not measurably affect time of induction or titer of antibodies. PMID:1112617

  14. Structural and biophysical analysis of sequence insertions in the Venezuelan Equine Encephalitis Virus macro domain.

    PubMed

    Guillén, Jaime; Lichière, Julie; Rabah, Nadia; Beitzel, Brett F; Canard, Bruno; Coutard, Bruno

    2015-04-02

    Random transposon insertions in viral genomes can be used to reveal genomic regions important for virus replication. We used these genomic data to evaluate at the protein level the effect of such insertions on the Venezuelan Equine Encephalitis Virus nsP3 macro domain. The structural analysis showed that transposon insertions occur mainly in loops connecting the secondary structure elements. Some of the insertions leading to a temperature sensitive viral phenotype (ts) are close to the cleavage site between nsP2 and nsP3 or the ADP-ribose binding site, two important functions of the macro domain. Using four mutants mimicking the transposon insertions, we confirmed that these insertions can affect the macro domain properties without disrupting the overall structure of the protein.

  15. Primary immunoglobulin response of herons to infection with Venezuelan encephalitis virus.

    PubMed

    Powers, C D; Dickerman, R W

    1975-02-01

    Seven to nine days after inoculation with a replicating antigen, Venezuelan encephalitis virus, hemagglutination-inhibiting antibodies were present in plasma of 18 to 20 black-crowned night herons (BCNH), 14 of 15 great egrets (ge) , and 7 of 7 snowy egrets (SE). 19S (immunoglobulin M) precedes 7S (immunoglobulin G) antibodies in all but one bird of six GE, six SE, and six BCNH. 19S antibodies were detected for only 2 to 4 weeks post-inoculation. The induction period for both types of antibody was prolonged by 2 to 6 days as compared with earlier studies in gallinaceous birds using nonreplicating antigens. A marked delay in reaching peak titer of 7S antibodies was also observed. Hemagglutination inhibition tests were nearly as sensitive as neutralization tests for detecting 19S and early 7S antibodies. Size of virus inoculum did not measurably affect time of induction or titer of antibodies.

  16. Experimental Infection of Potential Reservoir Hosts with Venezuelan Equine Encephalitis Virus, Mexico

    PubMed Central

    Deardorff, Eleanor R.; Forrester, Naomi L.; Travassos da Rosa, Amelia P.; Estrada-Franco, Jose G.; Navarro-Lopez, Roberto; Tesh, Robert B.

    2009-01-01

    In 1993, an outbreak of encephalitis among 125 affected equids in coastal Chiapas, Mexico, resulted in a 50% case-fatality rate. The outbreak was attributed to Venezuelan equine encephalitis virus (VEEV) subtype IE, not previously associated with equine disease and death. To better understand the ecology of this VEEV strain in Chiapas, we experimentally infected 5 species of wild rodents and evaluated their competence as reservoir and amplifying hosts. Rodents from 1 species (Baiomys musculus) showed signs of disease and died by day 8 postinoculation. Rodents from the 4 other species (Liomys salvini, Oligoryzomys fulvescens, Oryzomys couesi, and Sigmodon hispidus) became viremic but survived and developed neutralizing antibodies, indicating that multiple species may contribute to VEEV maintenance. By infecting numerous rodent species and producing adequate viremia, VEEV may increase its chances of long-term persistence in nature and could increase risk for establishment in disease-endemic areas and amplification outside the disease-endemic range. PMID:19331726

  17. Venezuelan equine encephalitis in Panama: fatal endemic disease and genetic diversity of etiologic viral strains.

    PubMed

    Quiroz, Evelia; Aguilar, Patricia V; Cisneros, Julio; Tesh, Robert B; Weaver, Scott C

    2009-06-30

    Venezuelan equine encephalitis (VEE) is a reemerging, mosquito-borne viral disease of the neotropics that is severely debilitating and sometimes fatal to humans. Periodic epidemics mediated by equine amplification have been recognized since the 1920s, but interepidemic disease is rarely recognized. We report here clinical findings and genetic characterization of 42 cases of endemic VEE detected in Panama from 1961-2004. Recent clusters of cases occurred in Darien (eastern Panama) and Panama provinces (central Panama) near rainforest and swamp habitats. Patients ranged from 10 months to 48 years of age, and the more severe cases with neurological complications, including one fatal infection, were observed in children. The VEE virus strains isolated from these cases all belonged to an enzootic, subtype ID lineage known to circulate among sylvatic vectors and rodent reservoir hosts in Panama and Peru. These findings underscore endemic VEE as an important but usually neglected arboviral disease of Latin America.

  18. Candidate Vectors and Rodent Hosts of Venezuelan Equine Encephalitis Virus, Chiapas, 2006–2007

    PubMed Central

    Deardorff, Eleanor R.; Estrada-Franco, Jose G.; Freier, Jerome E.; Navarro-Lopez, Roberto; Da Rosa, Amelia Travassos; Tesh, Robert B.; Weaver, Scott C.

    2011-01-01

    Enzootic Venezuelan equine encephalitis virus (VEEV) has been known to occur in Mexico since the 1960s. The first natural equine epizootic was recognized in Chiapas in 1993 and since then, numerous studies have characterized the etiologic strains, including reverse genetic studies that incriminated a specific mutation that enhanced infection of epizootic mosquito vectors. The aim of this study was to determine the mosquito and rodent species involved in enzootic maintenance of subtype IE VEEV in coastal Chiapas. A longitudinal study was conducted over a year to discern which species and habitats could be associated with VEEV circulation. Antibody was rarely detected in mammals and virus was not isolated from mosquitoes. Additionally, Culex (Melanoconion) taeniopus populations were found to be spatially related to high levels of human and bovine seroprevalence. These mosquito populations were concentrated in areas that appear to represent foci of stable, enzootic VEEV circulation. PMID:22144461

  19. Tectonic implications of tomographic images of subducted lithosphere beneath Northwestern South America

    SciTech Connect

    Van Der Hilst, R. ); Mann, P. )

    1993-02-01

    Tomographic images and deep seismicity of the mantle beneath northwestern South America support the existence of extensive and continuous subducted slabs which may be important controls on the neotectonic deformation of the overriding South America plate. Using tomographic data, we have estimated lateral continuity, regional dip, downdip length and approximate convergence direction of two, largely aseismic slabs. Tomographic data suggests that the Cauca slab, previously defined using earthquakes beneath southern Colombia, extends 300 km into the mantle beneath northern Colombia, has an average dip of 50[degrees], and is the downdip extension of Eocene to Miocene Panama island arc and Oligocene-Miocene oceanic crust of the Nazca plate. The Maracaibo slab of northern Colombia and western Venezuela extends up to 450 km into the mantle at an average angle of 16[degrees] and is the downdip extension of Late Cretaceous oceanic plateau crust of the Caribbean Sea. The boundary between the two slabs is less than 50 km in width. The Maracaibo and northern Cauca slabs are generally aseismic and not associated with an overlying volcanic arc. Instead, both slabs are overlain by broad zones of diffuse active faulting and topography in the northern Andes. The shallow dip, angle of oblique subduction and thickness of the Maracaibo slab may produce crustal deformation including northward tectonic escape of the Maracaibo block, a triangular wedge of continental crust in the overriding South America plate.

  20. Association of common variants on chromosome 8q24 with gastric cancer in Venezuelan patients.

    PubMed

    Labrador, Luis; Torres, Keila; Camargo, Maria; Santiago, Laskhmi; Valderrama, Elvis; Chiurillo, Miguel Angel

    2015-07-15

    Gastric cancer remains one of the leading causes of death in the world, being Central and South America among the regions showing the highest incidence and mortality rates worldwide. Although several single nucleotide polymorphisms (SNPs) identified in the chromosomal region 8q24 by genome-wide association studies have been related with the risk of different kinds of cancers, their role in the susceptibility of gastric cancer in Latin American populations has not been evaluated yet. Hereby, we performed a case-control study to explore the associations between three SNPs at 8q24 and gastric cancer risk in Venezuelan patients. We analyzed rs1447295, rs4733616 and rs6983267 SNPs in 122 paraffin-embedded tumor samples from archival bank and 129 samples with chronic gastritis (obtained by upper endoscopy during the study) from the Central Hospital of Barquisimeto (Lara, Venezuela). Genotypes were determined by PCR-RFLP reactions designed in this study for efficient genotyping of formalin-fixed/paraffin-embedded tissues. No significant differences in genotype frequencies between case and control groups were found. However, carriers of the homozygous TT genotype of SNP rs4733616 had an increased risk of developing poorly differentiated gastric cancer according to the codominant (OR=3.59, P=0.035) and the recessive models (OR=4.32, P=0.014, best-fitting model of inheritance), adjusted by age and gender. Our study suggests that the SNP rs4733616 is associated with susceptibility to poorly differentiated gastric cancer in Venezuelans. Additional studies are needed to further interrogate the prognostic value of the rs4733616 marker in this high-risk population for gastric cancer.

  1. Altiplano-Puna volcanic complex of the central Andes

    NASA Technical Reports Server (NTRS)

    De Silva, S. L.

    1989-01-01

    A model is presented accounting for many features of the Altiplano-Puna volcanic complex situated in the Central Volcanic Zone of the Andes which contains 50 recently active volcanoes. The dominant elements of the complex are several large nested caldera complexes which are the source structures for the major regionally distributed ignimbrite sheets that characterize the complex. The study of the complex reveals the importance of the intersection of subsidiary axis-oblique tectonic trends related to regional stress fields peculiar to individual oceanic ridge sections with the axis-parallel trends predominant at all spreading centers in localizing hydrothermal discharge zones.

  2. Early local last glacial maximum in the tropical Andes.

    PubMed

    Smith, Jacqueline A; Seltzer, Geoffrey O; Farber, Daniel L; Rodbell, Donald T; Finkel, Robert C

    2005-04-29

    The local last glacial maximum in the tropical Andes was earlier and less extensive than previously thought, based on 106 cosmogenic ages (from beryllium-10 dating) from moraines in Peru and Bolivia. Glaciers reached their greatest extent in the last glacial cycle approximately 34,000 years before the present and were retreating by approximately 21,000 years before the present, implying that tropical controls on ice volumes were asynchronous with those in the Northern Hemisphere. Our estimates of snowline depression reflect about half the temperature change indicated by previous widely cited figures, which helps resolve the discrepancy between estimates of terrestrial and marine temperature depression during the last glacial cycle.

  3. Autosomal microsatellite data from Northwestern Colombia.

    PubMed

    Palacio, Oscar Darío; Triana, Omar; Gaviria, Aníbal; Ibarra, Adriana Alexandra; Ochoa, Luz Mariela; Posada, Yeny; Maya, María Clara; Lareu, María Victoria; Brión, María; Acosta, María Amparo; Carracedo, Angel

    2006-07-13

    Allele frequencies and some forensic parameters for 12 autosomal microsatellites (CSF1PO, TPOX, THO1, VWA, D16S539, D7S820, D13S317, D5S818, F13A1, FESFPS, F13B, LPL) were estimated from three departments from Northwestern Colombia. The total number of samples analysed was 1045 individuals. Comparative analysis among the three studied departments and with other published Colombian populations were also performed and discussed.

  4. Peralkaline silicic volcanic rocks in northwestern nevada.

    PubMed

    Noble, D C; Chipman, D W; Giles, D L

    1968-06-21

    Late Tertiary silicic ashflow tuffs and lavas peralkaline in chemical character (atomic Na + K greater than Al), mainly comendites, occur over wide areas in northwestern Nevada and appear to be widespread in southeastern Oregon. Such peralkaline rocks-which are not uncommon in the western United States-and other chemically unusual silicic rocks are found near the margins rather than toward the center of the Great Basin.

  5. Flood of September 2008 in Northwestern Indiana

    USGS Publications Warehouse

    Fowler, Kathleen K.; Kim, Moon H.; Menke, Chad D.; Arvin, Donald V.

    2010-01-01

    During September 12-15, 2008, rainfall ranging from 2 to more than 11 inches fell on northwestern Indiana. The rainfall resulted in extensive flooding on many streams within the Lake Michigan and Kankakee River Basins during September 12-18, causing two deaths, evacuation of hundreds of residents, and millions of dollars of damage to residences, businesses, and infrastructure. In all, six counties in northwestern Indiana were declared Federal disaster areas. U.S. Geological Survey (USGS) streamgages at four locations recorded new record peak streamflows as a result of the heavy rainfall. Peak-gage-height data, peak-streamflow data, annual exceedance probabilities, and recurrence intervals are tabulated in this report for 10 USGS streamgages in northwestern Indiana. Recurrence intervals of flood-peak streamflows were estimated to be greater than 100 years at six streamgages. Because flooding was particularly severe in the communities of Munster, Dyer, Hammond, Highland, Gary, Lake Station, Hobart, Schererville, Merrillville, Michiana Shores, and Portage, high-water-park data collected after the flood were tabulated for those communities. Flood peak inundation maps and water-surface profiles for selected streams were made in a geographic information system by combining high-water-mark data with the highest resolution digital elevation model data available.

  6. Episodic Cenozoic volcanism and tectonism in the Andes of Peru

    USGS Publications Warehouse

    Noble, D.C.; McKee, E.H.; Farrar, E.; Petersen, U.

    1974-01-01

    Radiometric and geologic information indicate a complex history of Cenozoic volcanism and tectonism in the central Andes. K-Ar ages on silicic pyroclastic rocks demonstrate major volcanic activity in central and southern Peru, northern Chile, and adjacent areas during the Early and Middle Miocene, and provide additional evidence for volcanism during the Late Eocene. A provisional outline of tectonic and volcanic events in the Peruvian Andes during the Cenozoic includes: one or more pulses of igneous activity and intense deformation during the Paleocene and Eocene; a period of quiescence, lasting most of Oligocene time; reinception of tectonism and volcanism at the beginning of the Miocene; and a major pulse of deformation in the Middle Miocene accompanied and followed through the Pliocene by intense volcanism and plutonism. Reinception of igneous activity and tectonism at about the Oligocene-Miocene boundary, a feature recognized in other circum-Pacific regions, may reflect an increase in the rate of rotation of the Pacific plate relative to fixed or quasifixed mantle coordinates. Middle Miocene tectonism and latest Tertiary volcanism correlates with and probably is genetically related to the beginning of very rapid spreading at the East Pacific Rise. ?? 1974.

  7. 1,5 iodonaphthyl Azide Inactivated V3526 Protects against Aerosol Challenge with Virulent Venezuelan Equine Encephalitis Virus.

    DTIC Science & Technology

    2016-06-02

    UNCLASSIFIED 2 Abstract: Venezuelan equine encephalitis virus (VEEV) is a New World alphavirus. There is no licensed vaccine for prophylaxis...against VEEV. VEEV is highly infectious in aerosolized form and has been identified as a bio-terrorism agent. The current IND vaccine is poorly...V3526 may be explored further for specific development as an effective vaccine candidate against aerosol challenge of virulent VEEV. Highlights

  8. IGG Subclass and Isotype Specific Immunoglobulin Responses to LASSA fever and Venezuelan Equine Encephalomyelitis: Natural Infection and Immunication

    DTIC Science & Technology

    1989-03-01

    DAIC FLL COpy AD-A218 815 A_ ARMY PROJECT ORDER NO: 88PP8804 TITLE: IGG SUBCLASS & ISOTYPE SPECIFIC IMMUNOGLOBULIN RESPONSES TO LASSA FEVER...TITLE (include Security Classification) IGG SUBCLASS & ISOTYPE SPECIFIC IMMUNOGLOBULIN RESPONSES TO LASSA FEVER & VENEZUELAN EQUINE ENCEPHALOMYELITIS...Immunoglobulin; IgG Sub- 06 01 classes; Lassa Fever; VEE; PO; Togavirus; IgG; IgA; IgM; 06 13 Arenavirus; Hemmorhagic Fever: BD; RA I 19, ABSTRACT

  9. Susceptibility of Psorophora confinnis (Diptera: Culicidae) to infection with epizootic (subtype IC) and enzootic (subtype ID) Venezuelan Equine encephalitis viruses.

    PubMed

    Ortiz, Diana I; Anishchenko, Michael; Weaver, Scott C

    2005-09-01

    To test the hypothesis that adaptation to epizootic mosquito vectors mediates the emergence of Venezuelan equine encephalitis virus (family Togaviridae, genus Alphavirus, VEEV) from enzootic progenitors, the susceptibility of the epizootic vector Psorophora confinnis (Lynch-Arribalzaga) to epizootic versus enzootic strains was evaluated. Artificial bloodmeals containing subtype IC strains isolated during the 1962-1964, 1992-1993, and 1995 Venezuelan/Colombian epizootics and closely related Venezuelan enzootic subtype ID strains were used to compare mosquito infectivity and transmission potential. Strains from the smaller 1992-1993 epizootic showed lower or equal infectivity and replication compared with enzootic viruses and to strains isolated during the larger 1962-1964 and 1995 epizootics. These experiments failed to provide evidence that Ps. confinnis selects for epizootic VEEV viruses with higher infectivity, as has been shown for Aedes (Ochlerotatus) taeniorhynchus (Wiedemann). Nonetheless, its high susceptibility, abundance in enzootic and epizootic regions, and feeding behavior suggest that Ps. confinnis is an important bridge vector for both enzootic and epizootic VEEV.

  10. Demography of Dall's sheep in northwestern Alaska

    USGS Publications Warehouse

    Kleckner, Christopher; Udevitz, Mark S.; Adams, Layne G.; Shults, Brad S.

    2003-01-01

    Dall’s sheep in northwestern Alaska declined in the early 1990s following the severe 1989-90 and 1990-91 winters. In the Baird Mountains of Noatak National Preserve, estimates of adult sheep declined by 50% from 800 in 1989 to under 400 in 1991. Population counts remained low throughout 1991 to 1996, reaching a minimum of 244 adult sheep in 1996. Few lambs were observed during annual midsummer aerial surveys in 1991 to 1994. We suspect that these declines resulted from a combination of poorer nutritional condition and increased vulnerability of sheep to predation resulting from severe winter conditions.As a result of these declines, both subsistence and sport hunting seasons were closed by emergency order in 1991, resulting in substantial management controversy. The affected publics, although willing to accept the closures, questioned the validity of the sheep survey data and strongly emphasized their interest in restoring harvests as soon as populations increased sufficiently. In 1995 the Northwest Arctic Regional Advisory Council, the local advisory committee for the Federal Subsistence Board, passed a motion supporting efforts to initiate research on sheep populations in the region to better understand the factors limiting sheep populations and to evaluate sheep survey methodologies.Currently estimates of Dall’s sheep population size and composition in the western Brooks Range are based on intensive fixed-wing aerial surveys conducted annually since 1986 in areas including the Baird Mountains. The annual variation in recent Baird Mountains aerial counts cannot be explained with reasonable assumptions about reproduction and survival, suggesting that there is some variability in the proportion of the population observed each year or that a substantial number of sheep move during the survey. Prior to our research, no attempt had been made to estimate visibility bias or precision for these surveys.Our understanding of Dall’s sheep population biology comes

  11. Andes virus and first case report of Bermejo virus causing fatal pulmonary syndrome.

    PubMed

    Padula, Paula; Della Valle, Marcelo González; Alai, María Garcia; Cortada, Pedro; Villagra, Mario; Gianella, Alberto

    2002-04-01

    Two suspected hantavirus pulmonary syndrome (HPS) cases from Bolivia occurred in May and July 2000 and were confirmed by enzyme-linked immunosorbent assay (ELISA)-ANDES using N-Andes recombinant antigen serology. Clot RNAs from the two patients were subjected to reverse transcription-polymerase chain reaction (PCR) amplification and sequencing. We describe two characterized cases of HPS. One was caused by infection with Bermejo virus and the other with Andes Nort viral lineage, both previously obtained from Oligoryzomys species. This is the first report of molecular identification of a human hantavirus associated with Bermejo virus.

  12. Venezuelan Equine Encephalitis Virus Induces Apoptosis through the Unfolded Protein Response Activation of EGR1

    PubMed Central

    Baer, Alan; Lundberg, Lindsay; Swales, Danielle; Waybright, Nicole; Pinkham, Chelsea; Dinman, Jonathan D.

    2016-01-01

    ABSTRACT Venezuelan equine encephalitis virus (VEEV) is a previously weaponized arthropod-borne virus responsible for causing acute and fatal encephalitis in animal and human hosts. The increased circulation and spread in the Americas of VEEV and other encephalitic arboviruses, such as eastern equine encephalitis virus and West Nile virus, underscore the need for research aimed at characterizing the pathogenesis of viral encephalomyelitis for the development of novel medical countermeasures. The host-pathogen dynamics of VEEV Trinidad donkey-infected human astrocytoma U87MG cells were determined by carrying out RNA sequencing (RNA-Seq) of poly(A) and mRNAs. To identify the critical alterations that take place in the host transcriptome following VEEV infection, samples were collected at 4, 8, and 16 h postinfection and RNA-Seq data were acquired using an Ion Torrent PGM platform. Differential expression of interferon response, stress response factors, and components of the unfolded protein response (UPR) was observed. The protein kinase RNA-like endoplasmic reticulum kinase (PERK) arm of the UPR was activated, as the expression of both activating transcription factor 4 (ATF4) and CHOP (DDIT3), critical regulators of the pathway, was altered after infection. Expression of the transcription factor early growth response 1 (EGR1) was induced in a PERK-dependent manner. EGR1−/− mouse embryonic fibroblasts (MEFs) demonstrated lower susceptibility to VEEV-induced cell death than isogenic wild-type MEFs, indicating that EGR1 modulates proapoptotic pathways following VEEV infection. The influence of EGR1 is of great importance, as neuronal damage can lead to long-term sequelae in individuals who have survived VEEV infection. IMPORTANCE Alphaviruses represent a group of clinically relevant viruses transmitted by mosquitoes to humans. In severe cases, viral spread targets neuronal tissue, resulting in significant and life-threatening inflammation dependent on a combination

  13. Ancient ice islands in salt lakes of the Central Andes

    USGS Publications Warehouse

    Hurlbert, S.H.; Chang, Cecily C.Y.

    1984-01-01

    Massive blocks of freshwater ice and frozen sediments protrude from shallow, saline lakes in the Andes of southwestern Bolivia and northeastern Chile. These ice islands range up to 1.5 kilometers long, stand up to 7 meters above the water surface, and may extend out tens of meters and more beneath the unfrozen lake sediments. The upper surfaces of the islands are covered with dry white sediments, mostly aragonite or calcite. The ice blocks may have formed by freezing of the fresh pore water of lake sediments during the "little ice age." The largest blocks are melting rapidly because of possibly recent increases in geothermal heat flux through the lake bottom and undercutting by warm saline lake water during the summer.

  14. The last occurrence of Pleistocene megafauna in the Ecuadorian Andes

    NASA Astrophysics Data System (ADS)

    Coltorti, M.; Ficcarelli, G.; Jahren, H.; Espinosa, M. Moreno; Rook, L.; Torre, D.

    1998-12-01

    The latest Pleistocene—Holocene megafauna extinction is a global event, particularly dramatic in the Americas. In a previous paper the authors hypothesised a scenario for this extinction event in South America, where mastodonts first suffered from the changing climate environment, followed by the mylodonts and equids. These different latest Pleistocene—Holocene megafauna extinction "waves" in Ecuadorian Andes have been dated using 14C methods on material from selected sites in north and central Ecuadorian Interandean Depression. An outline of the physiographic evolution of the Interandean Depression in Ecuador is offered and the stratigraphic setting of the fossiliferous sites is discussed. The present results confirm the author's hypothesis on the megafauna extinction pattern, previously published in terms of relative age. The importance of climatic changes during Last Glacial Maximum at low latitudes is discussed.

  15. Modelling Andes Uplift Impact on Atmospheric Circulation: Consequences for Neogene Faunal and Floral Evolution ?

    NASA Astrophysics Data System (ADS)

    Sepulchre, P.; Sloan, L. C.; Fluteau, F.

    2007-12-01

    Tectonics in South America is marked by the uplift of the Andes during the Cenozoic. The Andes are approximately 7000 km long, oriented north-south, with some peak elevations in excess of 6000 m. Such a topographic structure has potentially a strong impact on atmospheric circulation. Climate model studies have showed that the Andes, as a topographic barrier, influence eastern Pacific Ocean climate and also meridional moisture transport above the south American continent. However, most studies have been done at the regional scale, and no quantification of rainfall changes due to a lower topography has been done. Here we use the high resolution Atmospheric General Circulation Model LMDz4 to quantify the impact of the Andes topography on the rainfall regime over the whole South American continent. Interpreting sensitivity experiments, we discuss about the tectonics history from 55 Ma to present-day and how to apply this method for Neogene paleoclimate, in a different continental configuration.

  16. Geology and petroleum resources of northwestern Africa

    SciTech Connect

    Peterson, J.A.; Klemme, H.D.

    1986-05-01

    The main onshore basins of northwestern Africa are (1) basins in the Atlas folded geosynclinal belt adjacent to the Mediterranean Sea, (2) the Tindouf, Bechar, and Reggane basins of western Algeria and southern Morocco, and (3) the Taoudeni basin of Mauritania and Mali. Coastal basins are (1) the Essaouria basin of southwestern Morocco, (2) the Tarfaya basin of Western Sahara, (3) the Senegal basin of Senegal and western Mauritania, (4) the Sierra Leone-Liberia basin, and (5) the Ivory Coast basin. The petroleum geology and resource potential of these basins is detailed.

  17. New records of mosquitoes from northwestern Argentina.

    PubMed

    Dantur Juri, María J; Stein, Marina; Rossi, Gustavo C; Navarro, Juan Carlos; Zaidenberg, Mario; Sallum, María A Mureb

    2012-06-01

    Eleven mosquito species, namely Aedes hastatus, Ae. fulvus, Coquillettidia albicosta, Cq. juxtamansonia, Culex aliciae, Cx. delpontei, Cx. oedipus, Cx. pedroi, Mansonia flaveola, Uranotaenia leucoptera, and Wyeomyia oblita, are recorded for the first time from northwestern Argentina. In addition, 3 species, Cx. brethesi, Limatus durhami, and Ur. nataliae, are reported for the first time from Salta Province. These records extend the geographical distribution of these 3 species to Salta Province. This study also extends the geographical distributions of Cq. nigricans, Cx. chidesteri, and Ma. humeralis to Jujuy Province and of Ae. meprai, Ae. milleri, Ae. oligopistus, Cx. brethesi, Cx. fernandezi, and Cx. tatoi to Tucumán Province.

  18. Complex brittle deformation pattern along the Southern Patagonian Andes (Argentina)

    NASA Astrophysics Data System (ADS)

    Barberón, Vanesa; Sue, Christian; Ronda, Gonzalo; Ghiglione, Matías

    2016-04-01

    The Southern Patagonian Andes is located in the southern extreme of the Pacific subduction zone, where the Antartic oceanic plate sinks underneath South America. The history of the area begins with compression during Paleozoic, Jurassic extension associated to the rift and opening of the South Atlantic Ocean, then a sag stage in the Lower Cretaceous followed by a foreland phase as a result of plate tectonics (Ghiglione et al., 2016). The kinematic study is concentrated in the Argentinean foothills, between 46°40' and 48° SL. We measured around 800 fault planes and their striaes with the sense of movement in order to characterize the stress field. The software used to make the stress inversion were Tensor (Delvaux, 2011) and Multiple Inverse Method MIM (Yamaji et al., 2011). The stress field map was built with the results of the MIM. We present new data from 48 sites located in the northern sector of the Southern Patagonian Andes. The measurements were made in several rocks from Paleozoic to Lower Cretaceous, even though most were taken in pyroclastic jurassic rocks from El Quemado Complex. Paleostress tensors obtained are mostly strike-slip, although a 25% is normal and there are a few compresional. The pattern of faults found is complex. In some sites the tensor can be locally linked to satellite images and observations from the field or be related to a major thrust front. There is no clear correlation between the age and/or lithology with the tensor since the youngest rocks measured are Lower Cretaceous. Probably there are several generations of family faults connected to different and recent tectonic phases then the paleostress tensors might correspond to the latest tectonic events.

  19. PROTOPLANETARY DISK STRUCTURE WITH GRAIN EVOLUTION: THE ANDES MODEL

    SciTech Connect

    Akimkin, V.; Wiebe, D.; Pavlyuchenkov, Ya.; Zhukovska, S.; Semenov, D.; Henning, Th.; Vasyunin, A.; Birnstiel, T. E-mail: dwiebe@inasan.ru E-mail: zhukovska@mpia.de E-mail: henning@mpia.de E-mail: tbirnstiel@cfa.harvard.edu

    2013-03-20

    We present a self-consistent model of a protoplanetary disk: 'ANDES' ('AccretioN disk with Dust Evolution and Sedimentation'). ANDES is based on a flexible and extendable modular structure that includes (1) a 1+1D frequency-dependent continuum radiative transfer module, (2) a module to calculate the chemical evolution using an extended gas-grain network with UV/X-ray-driven processes and surface reactions, (3) a module to calculate the gas thermal energy balance, and (4) a 1+1D module that simulates dust grain evolution. For the first time, grain evolution and time-dependent molecular chemistry are included in a protoplanetary disk model. We find that grain growth and sedimentation of large grains onto the disk midplane lead to a dust-depleted atmosphere. Consequently, dust and gas temperatures become higher in the inner disk (R {approx}< 50 AU) and lower in the outer disk (R {approx}> 50 AU), in comparison with the disk model with pristine dust. The response of disk chemical structure to the dust growth and sedimentation is twofold. First, due to higher transparency a partly UV-shielded molecular layer is shifted closer to the dense midplane. Second, the presence of big grains in the disk midplane delays the freeze-out of volatile gas-phase species such as CO there, while in adjacent upper layers the depletion is still effective. Molecular concentrations and thus column densities of many species are enhanced in the disk model with dust evolution, e.g., CO{sub 2}, NH{sub 2}CN, HNO, H{sub 2}O, HCOOH, HCN, and CO. We also show that time-dependent chemistry is important for a proper description of gas thermal balance.

  20. Noncytopathic Replication of Venezuelan Equine Encephalitis Virus and Eastern Equine Encephalitis Virus Replicons in Mammalian Cells

    PubMed Central

    Petrakova, Olga; Volkova, Eugenia; Gorchakov, Rodion; Paessler, Slobodan; Kinney, Richard M.; Frolov, Ilya

    2005-01-01

    Venezuelan equine encephalitis (VEE) and eastern equine encephalitis (EEE) viruses are important, naturally emerging zoonotic viruses. They are significant human and equine pathogens which still pose a serious public health threat. Both VEE and EEE cause chronic infection in mosquitoes and persistent or chronic infection in mosquito-derived cell lines. In contrast, vertebrate hosts infected with either virus develop an acute infection with high-titer viremia and encephalitis, followed by host death or virus clearance by the immune system. Accordingly, EEE and VEE infection in vertebrate cell lines is highly cytopathic. To further understand the pathogenesis of alphaviruses on molecular and cellular levels, we designed EEE- and VEE-based replicons and investigated their replication and their ability to generate cytopathic effect (CPE) and to interfere with other viral infections. VEE and EEE replicons appeared to be less cytopathic than Sindbis virus-based constructs that we designed in our previous research and readily established persistent replication in BHK-21 cells. VEE replicons required additional mutations in the 5′ untranslated region and nsP2 or nsP3 genes to further reduce cytopathicity and to become capable of persisting in cells with no defects in alpha/beta interferon production or signaling. The results indicated that alphaviruses strongly differ in virus-host cell interactions, and the ability to cause CPE in tissue culture does not necessarily correlate with pathogenesis and strongly depends on the sequence of viral nonstructural proteins. PMID:15919912

  1. Venezuelan Equine Encephalitis Virus in Iquitos, Peru: Urban Transmission of a Sylvatic Strain

    PubMed Central

    Morrison, Amy C.; Forshey, Brett M.; Notyce, Desiree; Astete, Helvio; Lopez, Victor; Rocha, Claudio; Carrion, Rebecca; Carey, Cristhiam; Eza, Dominique; Montgomery, Joel M.; Kochel, Tadeusz J.

    2008-01-01

    Enzootic strains of Venezuelan equine encephalitis virus (VEEV) have been isolated from febrile patients in the Peruvian Amazon Basin at low but consistent levels since the early 1990s. Through a clinic-based febrile surveillance program, we detected an outbreak of VEEV infections in Iquitos, Peru, in the first half of 2006. The majority of these patients resided within urban areas of Iquitos, with no report of recent travel outside the city. To characterize the risk factors for VEEV infection within the city, an antibody prevalence study was carried out in a geographically stratified sample of urban areas of Iquitos. Additionally, entomological surveys were conducted to determine if previously incriminated vectors of enzootic VEEV were present within the city. We found that greater than 23% of Iquitos residents carried neutralizing antibodies against VEEV, with significant associations between increased antibody prevalence and age, occupation, mosquito net use, and overnight travel. Furthermore, potential vector mosquitoes were widely distributed across the city. Our results suggest that while VEEV infection is more common in rural areas, transmission also occurs within urban areas of Iquitos, and that further studies are warranted to identify the precise vectors and reservoirs involved in urban VEEV transmission. PMID:19079600

  2. Altered mitochondrial dynamics as a consequence of Venezuelan Equine encephalitis virus infection.

    PubMed

    Keck, Forrest; Brooks-Faulconer, Taryn; Lark, Tyler; Ravishankar, Pavitra; Bailey, Charles; Salvador-Morales, Carolina; Narayanan, Aarthi

    2017-01-11

    Mitochondria are sentinel organelles that are impacted by various forms of cellular stress, including viral infections. While signaling events associated with mitochondria, including those activated by pathogen associated molecular patterns (PAMPs), are widely studied, alterations in mitochondrial distribution and changes in mitochondrial dynamics are also beginning to be associated with cellular insult. Cells of neuronal origin have been demonstrated to display remarkable alterations in several instances, including neurodegenerative disorders. Venezuelan Equine Encephalitis Virus (VEEV) is a New World alphavirus that infects neuronal cells and contributes to an encephalitic phenotype. We demonstrate that upon infection by the vaccine strain of VEEV (TC-83), astrocytoma cells experience a robust drop in mitochondrial activity, which corresponds with an increased accumulation of reactive oxygen species (ROS) in an infection-dependent manner. Infection status also corresponds with a prominent perinuclear accumulation of mitochondria. Cellular enzymatic machinery, including PINK1 and Parkin, appears to be enriched in mitochondrial fractions as compared with uninfected cells, which is indicative of mitochondrial damage. Dynamin related protein 1 (Drp1), a protein that is associated with mitochondrial fission, demonstrated a modest enrichment in mitochondrial fractions of infected cells. Treatment with an inhibitor of mitochondrial fission, Mdivi-1, led to a decrease in caspase cleavage, suggesting that mitochondrial fission was likely to contribute to apoptosis of infected cells. Finally, our data demonstrate that mitophagy ensues in infected cells. In combination, our data suggest that VEEV infection results in significant changes in the mitochondrial landscape that may influence pathological outcomes in the infected cell.

  3. Molecular profiles of Venezuelan isolates of Trypanosoma sp. by random amplified polymorphic DNA method.

    PubMed

    Perrone, T M; Gonzatti, M I; Villamizar, G; Escalante, A; Aso, P M

    2009-05-12

    Nine Trypanosoma sp. Venezuelan isolates, initially presumed to be T. evansi, were collected from three different hosts, capybara (Apure state), horse (Apure state) and donkey (Guarico state) and compared by the random amplification polymorphic DNA technique (RAPD). Thirty-one to 46 reproducible fragments were obtained with 12 of the 40 primers that were used. Most of the primers detected molecular profiles with few polymorphisms between the seven horse, capybara and donkey isolates. Quantitative analyses of the RAPD profiles of these isolates revealed a high degree of genetic conservation with similarity coefficients between 85.7% and 98.5%. Ten of the primers generated polymorphic RAPD profiles with two of the three Trypanosoma sp. horse isolates, namely TeAp-N/D1 and TeGu-N/D1. The similarity coefficient between these two isolates and the rest, ranged from 57.9% to 68.4% and the corresponding dendrogram clustered TeAp-N/D1 and Te Gu-N/D1 in a genetically distinct group.

  4. Genetic and anatomic determinants of enzootic Venezuelan equine encephalitis virus infection of Culex (Melanoconion) taeniopus.

    PubMed

    Kenney, Joan L; Adams, A Paige; Gorchakov, Rodion; Leal, Grace; Weaver, Scott C

    2012-01-01

    Venezuelan equine encephalitis (VEE) is a re-emerging, mosquito-borne viral disease with the potential to cause fatal encephalitis in both humans and equids. Recently, detection of endemic VEE caused by enzootic strains has escalated in Mexico, Peru, Bolivia, Colombia and Ecuador, emphasizing the importance of understanding the enzootic transmission cycle of the etiologic agent, VEE virus (VEEV). The majority of work examining the viral determinants of vector infection has been performed in the epizootic mosquito vector, Aedes (Ochlerotatus) taeniorhynchus. Based on the fundamental differences between the epizootic and enzootic cycles, we hypothesized that the virus-vector interaction of the enzootic cycle is fundamentally different from that of the epizootic model. We therefore examined the determinants for VEEV IE infection in the enzootic vector, Culex (Melanoconion) taeniopus, and determined the number and susceptibility of midgut epithelial cells initially infected and their distribution compared to the epizootic virus-vector interaction. Using chimeric viruses, we demonstrated that the determinants of infection for the enzootic vector are different than those observed for the epizootic vector. Similarly, we showed that, unlike A. taeniorhynchus infection with subtype IC VEEV, C. taeniopus does not have a limited subpopulation of midgut cells susceptible to subtype IE VEEV. These findings support the hypothesis that the enzootic VEEV relationship with C. taeniopus differs from the epizootic virus-vector interaction in that the determinants appear to be found in both the nonstructural and structural regions, and initial midgut infection is not limited to a small population of susceptible cells.

  5. Potential Sympatric Vectors and Mammalian Hosts of Venezuelan Equine Encephalitis Virus in Southern Mexico.

    PubMed

    Sotomayor-Bonilla, Jesús; Abella-Medrano, Carlos Antonio; Chaves, Andrea; Álvarez-Mendizábal, Paulina; Rico-Chávez, Óscar; Ibáñez-Bernal, Sergio; Rostal, Melinda K; Ojeda-Flores, Rafael; Barbachano-Guerrero, Arturo; Gutiérrez-Espeleta, Gustavo; Aguirre, A Alonso; Daszak, Peter; Suzán, Gerardo

    2017-04-06

    Arboviruses are important zoonotic agents with complex transmission cycles and are not well understood because they may involve many vectors and hosts. We studied sympatric wild mammals and hematophagous mosquitoes having the potential to act as hosts and vectors in two areas of southern Mexico. Mosquitoes, bats, and rodents were captured in Calakmul (Campeche) and Montes Azules (Chiapas), between November 2010 and August 2011. Spleen samples from 146 bats and 14 rodents were tested for molecular evidence of Venezuelan equine encephalitis virus (VEEV), eastern equine encephalitis virus (EEEV), western equine encephalitis virus (WEEV), and West Nile virus (WNV) using PCR protocols. Bat ( Artibeus lituratus , Carollia sowelli , Glossophaga soricina , and Sturnira parvidens) and rodent ( Sigmodon hispidus and Oryzomys alfaroi ) species were positive for VEEV. No individuals were positive for WNV, EEEV, or WEEV. A total of 1,298 mosquitoes were collected at the same sites, and five of the mosquito species collected were known VEEV vectors (Aedes fulvus, Mansonia indubitans, Psorophora ferox, Psorophora cilipes, and Psorophora confinnis). This survey simultaneously presents the first molecular evidence, to our knowledge, of VEEV in bats and rodents from southern Mexico and the identification of potential sympatric vectors. Studies investigating sympatric nonhuman hosts, vectors, and arboviruses must be expanded to determine arboviral dynamics in complex systems in which outbreaks of emerging and reemerging zoonoses are continuously occurring.

  6. Isolation and Phylogenetic Analysis of Mucambo Virus (Venezuelan Equine Encephalitis Complex Subtype IIIA) in Trinidad

    PubMed Central

    Auguste, Albert J.; Volk, Sara M.; Arrigo, Nicole C.; Martinez, Raymond; Ramkissoon, Vernie; Adams, A. Paige; Thompson, Nadin N.; Adesiyun, Abiodun A.; Chadee, Dave D.; Foster, Jerome E.; Travassos Da Rosa, Amelia P.A.; Tesh, Robert B.; Weaver, Scott C.; Carrington, Christine V. F.

    2009-01-01

    In the 1950s and 1960s, alphaviruses in the Venezuelan equine encephalitis (VEE) antigenic complex were the most frequently isolated arboviruses in Trinidad. Since then, there has been very little research performed with these viruses. Herein, we report on the isolation, sequencing, and phylogenetic analyses of Mucambo virus (MUCV; VEE complex subtype IIIA), including 6 recently isolated from Culex (Melanoconion) portesi mosquitoes and 11 previously isolated in Trinidad and Brazil. Results show that nucleotide and amino acid identities across the complete structural polyprotein for the MUCV isolates were 96.6 – 100% and 98.7 – 100%, respectively, and the phylogenetic tree inferred for MUCV was highly geographically- and temporally- structured. Bayesian analyses suggest the sampled MUCV lineages have a recent common ancestry of approximately 198 years (with a 95% highest posterior density (HPD) interval of 63 – 448 years) prior to 2007, and an overall rate of evolution of 1.28 × 10−4 substitutions/site/yr. PMID:19631956

  7. Characterization of Venezuelan vacuum residua and product vacuum residua obtained using the HDM{trademark} technology

    SciTech Connect

    Izquierdo, A.; Espidel, Y.; Fraile, R.

    1995-12-31

    Detailed characterization of heavy crudes and vacuum residua, as well as the resulting products of the necessary upgrading process, are of great importance in the use of these energy sources. The physical and chemical properties vary among different feedstocks and they determine different behavior during the upgrading process. This paper describes the characterization of five Venezuelan vacuum residua, 500{degrees}C+, and the vacuum residua of the products obtained when they were processed using the HDH{trademark} technology. The operating conditions were kept constant in order to be able to compare the reactivity of the different feedstocks. Special emphasis is given to the asphaltenes characterization and, in particular, to the results room the Average Molecular Parameters obtained by proton NMR. A correlation between these parameters and the reactivity was found. It was equally found that the asphaltenes of the feeds were very different in aromaticity, number of bridging aromatic carbons, and other properties involving the aromatic portion of these samples, whereas the asphaltenes of the resulting products had strong similarities. This indicates that despite the different nature o the starting material, the transformations during the process bring the high molecular weight aromatic components to similar structures.

  8. Histopathology and Distribution of Viral Antigens in Hamsters Infected with Virulent and Benign Venezuelan Encephalitis Viruses

    PubMed Central

    Jahrling, P. B.; Scherer, W. F.

    1973-01-01

    Lethalities and virulences of Venezuelan encephalitis (VE) viruses for hamsters were found to correlate with severity of histopathologic lesions in hematopoietic and brain tissues. Highly virulent strains (subtype I) destroyed marrow and lymphoid cells rapidly and produced intestinal wall damage; focal brain hemorrhages and destruction of Purkinje cells also occurred within the 4 to 5 days between subcutaneous inoculation and death. Like subtype I virus, a slightly less virulent strain (subtype II) also caused necrosis of bone marrow and brain lesions, but only minimal lymphoid cell damage occurred. The less virulent subtype III VE virus, which killed hamsters between 4 and 14 days after inoculation, usually caused no lesions in hematopoietic tissues, and deaths were related chiefly to hemorrhagic brain lesions and necrosis of Purkinje cells. Two VE viruses, benign for hamsters (the TC-83 attenuated vaccine strain and subtype IV), usually caused no necrosis of hematopoietic or brain tissues; focal extravasations of blood and swollen glial cells were found in brains of the rare hamsters that died. The degrees of necrosis seen in tissues stained with hematoxylin and eosin correlated with the quantities of viral antigens detected by fluorescent antibody, except in pancreas and small intestinal smooth muscle and glands, where antigens of subtype I virus were present without morphologic damage. ImagesFig 5-6Fig 7-8Fig 9Fig 10Fig 11Fig 12Fig 13Fig 14Fig 15Fig 16Fig 1-4 PMID:4578265

  9. Experimental Infection of Horses with an Attenuated Venezuelan Equine Encephalomyelitis Vaccine (Strain TC-83)

    PubMed Central

    Walton, Thomas E.; Alvarez, Otto; Buckwalter, Ross M.; Johnson, Karl M.

    1972-01-01

    Ten horses (Equus caballus) were vaccinated with strain TC-83 Venezuelan equine encephalomyelitis (VEE) virus vaccine. Febrile responses and leukopenia due to a reduction of lymphocytes and neutrophils were observed in all animals. Viremias were demonstrable in eight horses, with a maximum of 103.5 median tissue culture infectious dose units per ml of serum in two horses. Clinical illness with depression and anorexia were observed in five horses. Neutralizing (N), hemagglutination-inhibiting, and complement-fixing antibodies to the vaccine virus were demonstrable by 5, 6.5, and 7 days, respectively, after vaccination. Differential titrations of serum to six VEE strains revealed high titers of N antibody to vaccine virus, moderate titers to the epizootic Trinidad donkey no. 1 strain (VEE antigenic subtype I, variant A) from which TC-83 was derived, and low titers to two other epizootic strains (subtype I, variants B and C) in all horses at 1 month after vaccination; some animals responded with low levels of N antibody to the enzootic viruses (subtype I, variants D and E). Fourteen months after vaccination, six animals with detectable N antibody were challenged with MF-8 (subtype I, variant B), an epidemic-epizootic strain isolated in 1969 from a man in Honduras. All horses resisted challenge with the equine pathogenic strain of VEE. Marked increases of N antibody in most horses were demonstrable to some VEE strains when tested 1 month after challenge. PMID:4637604

  10. [Presence of lectins, tannins and protease inhibitors in venezuelan marine algae].

    PubMed

    Perez-Lorenzo, S; Levy-Benshimol, A; Gomez-Acevedo, S

    1998-01-01

    The presence of lectins, tannins and protease inhibitors was studied in 27 algae species collected at four Venezuelan coral rift sites. Among the species studied, only six had hemagglutinating activity, apparently due to their lectin content. Higher hemagglutinating titers were obtained when the extracts were tested on pronase-treated erythrocytes. Hemagglutination was inhibited by simple sugars and by bovine submaxillary gland mucine. GaINAc was the only inhibitor of the hemagglutination caused by Grateulopia filicina extracts. None of the compounds tested inhibited the hemagglutination caused by Halimeda opuntia. The polyvinylpolypirrolidone treatment abolished the hemagglutinating activity of both brown and red algae. However, in Grateulopia filicina and Hypnea cervicornis (Rhodophyta) hemagglutinating activity persisted after the polyvinylpolypirrolidone treatment, presumably due to the presence of true lectins in those algae. Tannin content (presumably phlorotannins) was higher in the Phaeophyta as compared to the Rhodophyta. The brown alga Padina gymnospora had the higher content of these polyphenols. Trypsin inhibitors were detected, in minute ammounts, only in Padina gymnospora (Phaeophyta) and Acantophora spicifera (Rhodophyta). No subtilisin inhibition was observed whatsoever.

  11. Noncytopathic replication of Venezuelan equine encephalitis virus and eastern equine encephalitis virus replicons in Mammalian cells.

    PubMed

    Petrakova, Olga; Volkova, Eugenia; Gorchakov, Rodion; Paessler, Slobodan; Kinney, Richard M; Frolov, Ilya

    2005-06-01

    Venezuelan equine encephalitis (VEE) and eastern equine encephalitis (EEE) viruses are important, naturally emerging zoonotic viruses. They are significant human and equine pathogens which still pose a serious public health threat. Both VEE and EEE cause chronic infection in mosquitoes and persistent or chronic infection in mosquito-derived cell lines. In contrast, vertebrate hosts infected with either virus develop an acute infection with high-titer viremia and encephalitis, followed by host death or virus clearance by the immune system. Accordingly, EEE and VEE infection in vertebrate cell lines is highly cytopathic. To further understand the pathogenesis of alphaviruses on molecular and cellular levels, we designed EEE- and VEE-based replicons and investigated their replication and their ability to generate cytopathic effect (CPE) and to interfere with other viral infections. VEE and EEE replicons appeared to be less cytopathic than Sindbis virus-based constructs that we designed in our previous research and readily established persistent replication in BHK-21 cells. VEE replicons required additional mutations in the 5' untranslated region and nsP2 or nsP3 genes to further reduce cytopathicity and to become capable of persisting in cells with no defects in alpha/beta interferon production or signaling. The results indicated that alphaviruses strongly differ in virus-host cell interactions, and the ability to cause CPE in tissue culture does not necessarily correlate with pathogenesis and strongly depends on the sequence of viral nonstructural proteins.

  12. Harmonizing regulations for biomedical research: a critical analysis of the US and Venezuelan systems.

    PubMed

    Di Tillio-Gonzalez, Dannie; Fischbach, Ruth L

    2008-12-01

    This article aims to compare the national legal systems that regulate biomedical research in an industrialized country (United States) and a developing country (Venezuela). A new international order is emerging in which Europe, Japan and the United States (US) are revising common guidelines and harmonizing standards. In this article, we analyze - as an example - the US system. This system is controlled by a federal agency structured to regulate research funded by the federal government uniformly, either in the US or abroad. In contrast, in Venezuela, a developing country, the creation of a centralized system is a slow process. Different types of ethical committees review research projects using non-uniform criteria. Consequently, various parallel organizations that conduct biomedical research, such as universities, research institutes and private hospitals have diverse regulations operating at a local level. Thus, the most relevant difference between the Venezuelan and the US systems is the degree of standardization. In the US, the review process is performed by institutional review boards (IRBs), which have a similar organization and maintain relationships with a centralized agency, following standard regulations. Although new proposals for establishing national regulations are currently being considered in Venezuela, the success of these initiatives will depend on promoting governmental efforts to create a more structured centralized system supported by a national regulatory framework. This system will need governmental financial support at all levels. This article proposes an integrated system to regulate research with human participants in Venezuela and other developing countries.

  13. An optical luminescence chronology for late Pleistocene aeolian activity in the Colombian and Venezuelan Llanos

    NASA Astrophysics Data System (ADS)

    Carr, Andrew S.; Armitage, Simon J.; Berrío, Juan-Carlos; Bilbao, Bibiana A.; Boom, Arnoud

    2016-03-01

    The lowland savannas (Llanos) of Colombia and Venezuela are covered by extensive aeolian landforms for which little chronological information exists. We present the first optically stimulated luminescence (OSL) age constraints for dunes in the Llanos Orientales of lowland Colombia and new ages for dunes in the Venezuelan Llanos. The sampled dunes are fully vegetated and show evidence of post-depositional erosion. Ages range from 4.5 ± 0.4 to 66 ± 4 ka, with the majority dating to 27-10 ka (Marine Isotope Stage 2). Some dunes accumulated quickly during the last glacial maximum, although most were active 16-10 ka. Accretion largely ceased after 10 ka. All dunes are elongated downwind from rivers, parallel with dry season winds, and are interpreted as source-bordering features. As they are presently isolated from fluvial sediments by gallery forest it is proposed that activity was associated with a more prolonged dry season, which restricted gallery forest, leading to greater sediment availability on river shorelines. Such variability in dry season duration was potentially mediated by the mean latitude of the ITCZ. The cessation of most dune accretion after ca. 10 ka suggests reduced seasonality and a more northerly ITCZ position, consistent with evidence from the Cariaco Basin.

  14. Venezuelan Equine Encephalitis Viruses (VEEV) in Argentina: Serological Evidence of Human Infection

    PubMed Central

    Pisano, María Belén; Oria, Griselda; Beskow, Geraldine; Aguilar, Javier; Konigheim, Brenda; Cacace, María Luisa; Aguirre, Luis; Stein, Marina; Contigiani, Marta Silvia

    2013-01-01

    Venezuelan equine encephalitis viruses (VEEV) are responsible for human diseases in the Americas, producing severe or mild illness with symptoms indistinguishable from dengue and other arboviral diseases. For this reason, many cases remain without certain diagnosis. Seroprevalence studies for VEEV subtypes IAB, ID, IF (Mosso das Pedras virus; MDPV), IV (Pixuna virus; PIXV) and VI (Rio Negro virus; RNV) were conducted in persons from Northern provinces of Argentina: Salta, Chaco and Corrientes, using plaque reduction neutralization test (PRNT). RNV was detected in all studied provinces. Chaco presented the highest prevalence of this virus (14.1%). Antibodies against VEEV IAB and -for the first time- against MDPV and PIXV were also detected in Chaco province. In Corrientes, seroprevalence against RNV was 1.3% in the pediatric population, indicating recent infections. In Salta, this was the first investigation of VEEV members, and antibodies against RNV and PIXV were detected. These results provide evidence of circulation of many VEE viruses in Northern Argentina, showing that surveillance of these infectious agents should be intensified. PMID:24349588

  15. [Venezuelan equine encephalitis. Determination of antibodies in the human population of Municipio Mirand, Estado Zulia, Venezuela].

    PubMed

    Ryder, S; Núñez-Camargo, J; Rangel, P; Añez, F

    1993-01-01

    With the purpose of determining antibodies prevalence against Venezuelan Equine Encephalitis Virus in the population of Puertos de Altagracia and Sabaneta de Palmas of Miranda county, Zulia State, Venezuela, 199 subjects were studied: 57 from Puertos de Altagracia and 142 from Sabaneta de Palmas. They were classified in older (42.78%) and younger (57.2%) than 15 years. The blood specimens were processed for Hemagglutination Inhibition Test using EEV antigen Goajira strain at pH 6.5. We found that all 57 specimens from Puertos de Altagracia were negative, whereas of 142 specimens from Sabaneta de Palmas 17 were positive (11.97%). Of these, one was from a subject less than 15 years-old (5.85%) and 16 from individuals more than 15 years-old (94.15%). Positive titers were higher than 1:160 in 80% of cases. Being Sabaneta de Palmas one of the most affected areas in the 1962 epidemic in the Miranda county and keeping the affected ones high positivity with elevated titers, we conclude that this population could represent an enzootic zone similar to Paez county where a similar situation, of high positivity and elevated titers, many years after the last epidemic occurred in that area, has been described.

  16. Ablation of Programmed -1 Ribosomal Frameshifting in Venezuelan Equine Encephalitis Virus Results in Attenuated Neuropathogenicity.

    PubMed

    Kendra, Joseph A; de la Fuente, Cynthia; Brahms, Ashwini; Woodson, Caitlin; Bell, Todd M; Chen, Bin; Khan, Yousuf A; Jacobs, Jonathan L; Kehn-Hall, Kylene; Dinman, Jonathan D

    2017-02-01

    The alphaviruses Venezuelan equine encephalitis virus (VEEV), eastern equine encephalitis virus (EEEV), and western equine encephalitis virus (WEEV) are arthropod-borne positive-strand RNA viruses that are capable of causing acute and fatal encephalitis in many mammals, including humans. VEEV was weaponized during the Cold War and is recognized as a select agent. Currently, there are no FDA-approved vaccines or therapeutics for these viruses. The spread of VEEV and other members of this family due to climate change-mediated vector range expansion underscores the need for research aimed at developing medical countermeasures. These viruses utilize programmed -1 ribosomal frameshifting (-1 PRF) to synthesize the viral trans-frame (TF) protein, which has previously been shown to be important for neuropathogenesis in the related Sindbis virus. Here, the alphavirus -1 PRF signals were characterized, revealing novel -1 PRF stimulatory structures. -1 PRF attenuation mildly affected the kinetics of VEEV accumulation in cultured cells but strongly inhibited its pathogenesis in an aerosol infection mouse model. Importantly, the decreased viral titers in the brains of mice infected with the mutant virus suggest that the alphavirus TF protein is important for passage through the blood-brain barrier and/or for neuroinvasiveness. These findings suggest a novel approach to the development of safe and effective live attenuated vaccines directed against VEEV and perhaps other closely related -1 PRF-utilizing viruses.

  17. Use of solid fuel in the production of pellets with Venezuelan iron ore

    SciTech Connect

    Rodriguez, A.; Ionescu, D.; Reyes, N.; Carrasquel, A.; Murati, C.; Guzman, J.L. )

    1993-01-01

    The pellet plant of Sidor consists of a dry grinding process for the iron ore and an induration process which takes place in a travelling grate furnace. The technical personnel considered the necessity of increasing the actual levels of productivity of 417 t/h and the abrasion index of 6%. To obtain this target, the technicians developed a series of pilot tests using solid fuel in the pelletizing mixture which gave positive results in the production of fluxed pellets using Venezuelan hematitic ore. At the industrial level the results were more successful than at pilot level; the productivity and the quality of pellets improved above the design values. The amount of coke used in the mixture was 0.7% and it required a significant change in the thermal profile of the furnace. The productivity increased 22.5% the abrasion index improved by 17.0%. The energy consumption was reduced to 25%. After this successful campaign there are plans for increasing the coke addition more than 1% which will allow abrasion levels between 4.0 and 4.5%, the compression strength between 320 and 330 Kg/pellet and also increase the productivity of the plant.

  18. [Microbiological assessment of the Gouda-type cheese-making process in a Venezuelan industry].

    PubMed

    Dáivila, Jacqueline; Reyes, Genara; Corzo, Otoniel

    2006-03-01

    The adoption of the Hazard Analysis and Critical Control Point (HACCP) system is necessary to assure the safety of the product in the cheese-making industry. The compliment of pre-requisite programs as Good Manufacture Practices (GMPs) and Sanitation Standard Operating Procedures (SSOPs) are required before the implementation of the HACCP plan. GMPs are the standards related to equipments, tools, personnel, etc. SSOPs are the procedures related to hygiene and sanitation of the plant and workers. The aim of this study was to assess the compliment of the pre-requisite programs and the microbiological conditions of the Gouda type cheese-making process in a Venezuelan processing plant before designing a HACCP plan. Samples were: (a) raw milk, pasteurized milk, curd and ripened cheese, (b) water, (c) environment of the production areas and ripening premises, (d) equipments before and after sanitation, (e) food handlers. Microbiological analyses were done according to COVENIN standards. This study showed that even though pasteurization process was effective to kill pathogen bacteria of the raw milk and the water was safe, however there are deficient manufacture practices in the hygiene as well as in sanitation of the plant and food handlers. Prerequisite programs (GMP-SSOP) of this industry need to be well established, controlled and evaluated.

  19. Venezuelan equine encephalitis virus entry mechanism requires late endosome formation and resists cell membrane cholesterol depletion

    SciTech Connect

    Kolokoltsov, Andrey A.; Fleming, Elisa H.; Davey, Robert A. . E-mail: radavey@utmb.edu

    2006-04-10

    Virus envelope proteins determine receptor utilization and host range. The choice of receptor not only permits specific targeting of cells that express it, but also directs the virus into specific endosomal trafficking pathways. Disrupting trafficking can result in loss of virus infectivity due to redirection of virions to non-productive pathways. Identification of the pathway or pathways used by a virus is, thus, important in understanding virus pathogenesis mechanisms and for developing new treatment strategies. Most of our understanding of alphavirus entry has focused on the Old World alphaviruses, such as Sindbis and Semliki Forest virus. In comparison, very little is known about the entry route taken by more pathogenic New World alphaviruses. Here, we use a novel contents mixing assay to identify the cellular requirements for entry of a New World alphavirus, Venezuelan equine encephalitis virus (VEEV). Expression of dominant negative forms of key endosomal trafficking genes shows that VEEV must access clathrin-dependent endocytic vesicles for membrane fusion to occur. Unexpectedly, the exit point is different from Old World alphaviruses that leave from early endosomes. Instead, VEEV also requires functional late endosomes. Furthermore, unlike the Old World viruses, VEEV entry is insensitive to cholesterol sequestration from cell membranes and may reflect a need to access an endocytic compartment that lacks cholesterol. This indicates fundamental differences in the entry route taken by VEEV compared to Old World alphaviruses.

  20. Endemic Venezuelan equine encephalitis in the Americas: hidden under the dengue umbrella

    PubMed Central

    Aguilar, Patricia V; Estrada-Franco, Jose G; Navarro-Lopez, Roberto; Ferro, Cristina; Haddow, Andrew D; Weaver, Scott C

    2011-01-01

    Venezuelan equine encephalitis (VEE) is an emerging infectious disease in Latin America. Outbreaks have been recorded for decades in countries with enzootic circulation, and the recent implementation of surveillance systems has allowed the detection of additional human cases in countries and areas with previously unknown VEE activity. Clinically, VEE is indistinguishable from dengue and other arboviral diseases and confirmatory diagnosis requires the use of specialized laboratory tests that are difficult to afford in resource-limited regions. Thus, the disease burden of endemic VEE in developing countries remains largely unknown, but recent surveillance suggests that it may represent up to 10% of the dengue burden in neotropical cities, or tens-of-thousands of cases per year throughout Latin America. The potential emergence of epizootic viruses from enzootic progenitors further highlights the need to strengthen surveillance activities, identify mosquito vectors and reservoirs and develop effective strategies to control the disease. In this article, we provide an overview of the current status of endemic VEE that results from spillover of the enzootic cycles, and we discuss public health measures for disease control as well as future avenues for VEE research. PMID:21765860

  1. Glaciation and topographic evolution of the Central Patagonian Andes since 6 Ma

    NASA Astrophysics Data System (ADS)

    Christeleit, E. C.; Laemel, R.; De Wolf, W. E.; Shuster, D. L.; Brandon, M. T.

    2013-12-01

    New and existing thermochronological data are used to model glacial erosion and topographic evolution of the central Patagonian Andes (~47S) over the last 6 Ma. The modern Andes are cut by large valleys and fjords with local valley relief of at least 2.5 km. It is currently thought that a formerly uniformly high Andes was 'buzzed' down to the elevation of the equilibrium line altitude, presumably in the last 2 Ma concurrent with late Cenozoic global cooling. However, studies of glacial debris show that glaciers were present in Patagonia as early as 6 Ma. The extent of these early glaciations is unclear, but recent work suggests that glacial valleys in the central Patagonian Andes were carved at a steady rate beginning at 6 Ma, implying that valley incision may be an important process in the topographic evolution of glaciated mountain ranges, rather than cirque retreat. To understand how valley relief has formed in the Andes, we dated 30 samples from Steffen Fjord in Chile using apatite (U-Th)/He thermochronology. We use this new data and existing thermochronological data in the region to estimate the topographic form of the central Andes at 6 Ma and model how the valley relief has evolved since the initiation of glaciation using Pecube.

  2. Shear wave anisotropy in northwestern South America and its link to the Caribbean and Nazca subduction geodynamics

    NASA Astrophysics Data System (ADS)

    Idárraga-García, J.; Kendall, J.-M.; Vargas, C. A.

    2016-09-01

    To investigate the subduction dynamics in northwestern South America, we measured SKS and slab-related local S splitting at 38 seismic stations. Comparison between the delay times of both phases shows that most of the SKS splitting is due to entrained mantle flow beneath the subducting Nazca and Caribbean slabs. On the other hand, the fast polarizations of local S-waves are consistently aligned with regional faults, which implies the existence of a lithosphere-confined anisotropy in the overriding plate, and that the mantle wedge is not contributing significantly to the splitting. Also, we identified a clear change in SKS fast directions at the trace of the Caldas Tear (˜5°N), which represents a variation in the subduction style. To the north of ˜5°N, fast directions are consistently parallel to the flat subduction of the Caribbean plate-Panama arc beneath South America, while to the south fast polarizations are subparallel to the Nazca-South America subduction direction. A new change in the SKS splitting pattern is detected at ˜2.8°N, which is related to another variation in the subduction geometry marked by the presence of a lithosphere-scale tearing structure, named here as Malpelo Tear; in this region, NE-SW-oriented SKS fast directions are consistent with the general dip direction of the underthrusting of the Carnegie Ridge beneath South America. Further inland, this NE-SW-trending mantle flow continues beneath the Eastern Cordillera of Colombia and Merida Andes of Venezuela. Finally, our results suggest that the subslab mantle flow in northwestern South America is strongly controlled by the presence of lithospheric tearing structures.

  3. Seismological observations in Northwestern South America: Evidence for two subduction segments, contrasting crustal thicknesses and upper mantle flow

    NASA Astrophysics Data System (ADS)

    Yarce, Jefferson; Monsalve, Gaspar; Becker, Thorsten W.; Cardona, Agustín; Poveda, Esteban; Alvira, Daniel; Ordoñez-Carmona, Oswaldo

    2014-12-01

    The cause of tectonic deformation in northwestern South America and its link to upper mantle structure and flow are debated. We use a combination of broadband and short period travel time seismic data for P-waves to show that observations are consistent with the presence of two subduction segments in Colombia and contrasting values of crustal thickness. In Northern Colombia, at latitudes greater than 6°N, most of the seismic stations are associated with negative teleseismic travel time residuals, relative to a regional mean, suggesting that the upper mantle is seismically faster than predicted from global models. In particular, for the Caribbean coastal plains there are no signs of significant anomalies in the upper mantle, evidenced by the small magnitude of the travel time delays and subdued Pn speeds (~ 7.97 km/s). To the southeast of such plains there is an increase in magnitude of the negative travel time residuals, including the Northern Eastern Cordillera, the Perija Range and the Merida Andes. An analysis of non-isostatic residual topography, based on a model of crustal thickness in northwestern South America, is consistent with a slab-associated upper mantle flow beneath the region just east of the Bucaramanga Nest. We interpret these results to indicate the presence of a Caribbean slab, initially flat beneath the Caribbean coastal plains, and steepening sharply in the southeast, including the area of Bucaramanga. For most of the western Andean region and the Pacific coast, south of 6°N, teleseismic differential travel time residuals are predominantly positive, indicating that the upper mantle is in general seismically slower than the reference model. Beneath the Central Cordillera, just to the east of this area, the residuals become smaller and predominantly negative; residual non-isostatic topography is negative as well. These features are probably related to the effect of the Nazca subduction developing an asthenospheric wedge.

  4. Ethnobotanical knowledge is vastly under-documented in northwestern South America.

    PubMed

    Cámara-Leret, Rodrigo; Paniagua-Zambrana, Narel; Balslev, Henrik; Macía, Manuel J

    2014-01-01

    A main objective of ethnobotany is to document traditional knowledge about plants before it disappears. However, little is known about the coverage of past ethnobotanical studies and thus about how well the existing literature covers the overall traditional knowledge of different human groups. To bridge this gap, we investigated ethnobotanical data-collecting efforts across four countries (Colombia, Ecuador, Peru, Bolivia), three ecoregions (Amazon, Andes, Chocó), and several human groups (including Amerindians, mestizos, and Afro-Americans). We used palms (Arecaceae) as our model group because of their usefulness and pervasiveness in the ethnobotanical literature. We carried out a large number of field interviews (n = 2201) to determine the coverage and quality of palm ethnobotanical data in the existing ethnobotanical literature (n = 255) published over the past 60 years. In our fieldwork in 68 communities, we collected 87,886 use reports and documented 2262 different palm uses and 140 useful palm species. We demonstrate that traditional knowledge on palm uses is vastly under-documented across ecoregions, countries, and human groups. We suggest that the use of standardized data-collecting protocols in wide-ranging ethnobotanical fieldwork is a promising approach for filling critical information gaps. Our work contributes to the Aichi Biodiversity Targets and emphasizes the need for signatory nations to the Convention on Biological Diversity to respond to these information gaps. Given our findings, we hope to stimulate the formulation of clear plans to systematically document ethnobotanical knowledge in northwestern South America and elsewhere before it vanishes.

  5. Ethnobotanical Knowledge Is Vastly Under-Documented in Northwestern South America

    PubMed Central

    Cámara-Leret, Rodrigo; Paniagua-Zambrana, Narel; Balslev, Henrik; Macía, Manuel J.

    2014-01-01

    A main objective of ethnobotany is to document traditional knowledge about plants before it disappears. However, little is known about the coverage of past ethnobotanical studies and thus about how well the existing literature covers the overall traditional knowledge of different human groups. To bridge this gap, we investigated ethnobotanical data-collecting efforts across four countries (Colombia, Ecuador, Peru, Bolivia), three ecoregions (Amazon, Andes, Chocó), and several human groups (including Amerindians, mestizos, and Afro-Americans). We used palms (Arecaceae) as our model group because of their usefulness and pervasiveness in the ethnobotanical literature. We carried out a large number of field interviews (n = 2201) to determine the coverage and quality of palm ethnobotanical data in the existing ethnobotanical literature (n = 255) published over the past 60 years. In our fieldwork in 68 communities, we collected 87,886 use reports and documented 2262 different palm uses and 140 useful palm species. We demonstrate that traditional knowledge on palm uses is vastly under-documented across ecoregions, countries, and human groups. We suggest that the use of standardized data-collecting protocols in wide-ranging ethnobotanical fieldwork is a promising approach for filling critical information gaps. Our work contributes to the Aichi Biodiversity Targets and emphasizes the need for signatory nations to the Convention on Biological Diversity to respond to these information gaps. Given our findings, we hope to stimulate the formulation of clear plans to systematically document ethnobotanical knowledge in northwestern South America and elsewhere before it vanishes. PMID:24416449

  6. Tectonic control on denudation rates in the central Bolivian Andes

    NASA Astrophysics Data System (ADS)

    Zeilinger, Gerold; Kober, Florian; Hippe, Kristina; Lendzioch, Theodora; Grischott, Reto; Pillco Zolá, Ramiro; Christl, Markus

    2013-04-01

    Effects of a positive feedback loop between erosion and tectonics have been shown by analogue and numerical models and have been inferred from field observations at the scale of mountain ranges. We present new data from the Bolivian Andes supporting these observations, although common geomorphic parameters do not indicate a simple correlation. The upper Rio Grande segment, located between Cochabamba, Santa Cruz and Sucre, drains a major catchment in the central Bolivian Cordillera, from the Eastern Cordillera (EC) in the W, through the Interandean Zone (IAZ) and the Subandes (SA) in the E. The catchment covers an area of 58939 km² with an altitude range from 400 to 5150 m above sea level. Geologically, the Bolivian Andes comprise (from W to E) the Altiplano, the EC, the IAZ and the SA fold and thrust belts. The Altiplano represents an almost perfectly closed basin with distinct barriers defined by the Western Cordillera and Eastern Cordillera. The Rio Grande does not reach the Altiplano (unlike Rio La Paz and Rio Consata) but has its western drainage divide along the high peaks of the EC that experienced a period of intense shortening between Late Oligocene and Miocene. Near Cochabamba, the EC comprises metasedimentary siliciclastic rocks of Ordovician age. These rocks are overlain by Cretaceous to Paleocene and / or Neogene sediments with an angular unconformity. The IAZ and SA form an east-vergent fold and thrust belt and comprise Paleozoic and Mesozoic units. Farther east, the structures of the SA progressively include Neogene foreland strata of the Chaco foreland basin. The Chaco basin rests on the Brazilian shield east of the Subandean Belt and forms the modern foreland basin, where the lower Rio Grande catchment is sited. We obtained 58 cosmogenic 10Be catchment wide denudation rates for the Rio Grande catchments upstream of Abapó. They range from 7 mm/kyr to 1550 mm/kyr thus integrating at maximum over the last 10.000 years, with a mean of 262 mm/kyr. In

  7. Preliminary bathymetry of Northwestern Fiord and Neoglacial changes of Northwestern Glacier

    USGS Publications Warehouse

    Post, Austin

    1980-01-01

    The first preliminary bathymetry (at 1:20,000 scale) and other scientific investigations of Northwestern Fiord, Alaska, were conducted by the Research Vessel Growler in 1978, disclosing this 10.5-mile-long branched waterway to be a deep basin enclosed by a terminal-moraine shoal. The basin was formerly filled by Northwestern Glacier, which began a drastic retreat around 1909 and reached the head of the main arm around 1960. Soundings and profiles show the main channel to be as much as 970 feet deep and to have the typical U shape of a severely glacially eroded valley; since the glacier 's retreat, sediments have formed nearly level deposits in the deepest reaches, while the rest of the basin has a hard, rocky bottom. Preneoglacial forest debris dated by carbon-14 indicates Northwestern Glacier to have advanced into the fiord prior to 1,385 years before present (B.P.); a branch glacier evidently advanced into forest 1,635 years B.P. The combined glaciers from several arms culminated on the present terminal-moraine shoal around 1894. (USGS)

  8. Into the Andes: multiple independent colonizations drive montane diversity in the Neotropical clearwing butterflies Godyridina.

    PubMed

    Chazot, Nicolas; Willmott, Keith R; Condamine, Fabien L; De-Silva, Donna Lisa; Freitas, André V L; Lamas, Gerardo; Morlon, Hélène; Giraldo, Carlos E; Jiggins, Chris D; Joron, Mathieu; Mallet, James; Uribe, Sandra; Elias, Marianne

    2016-11-01

    Understanding why species richness peaks along the Andes is a fundamental question in the study of Neotropical biodiversity. Several biogeographic and diversification scenarios have been proposed in the literature, but there is confusion about the processes underlying each scenario, and assessing their relative contribution is not straightforward. Here, we propose to refine these scenarios into a framework which evaluates four evolutionary mechanisms: higher speciation rate in the Andes, lower extinction rates in the Andes, older colonization times and higher colonization rates of the Andes from adjacent areas. We apply this framework to a species-rich subtribe of Neotropical butterflies whose diversity peaks in the Andes, the Godyridina (Nymphalidae: Ithomiini). We generated a time-calibrated phylogeny of the Godyridina and fitted time-dependent diversification models. Using trait-dependent diversification models and ancestral state reconstruction methods we then compared different biogeographic scenarios. We found strong evidence that the rates of colonization into the Andes were higher than the other way round. Those colonizations and the subsequent local diversification at equal rates in the Andes and in non-Andean regions mechanically increased the species richness of Andean regions compared to that of non-Andean regions ('species-attractor' hypothesis). We also found support for increasing speciation rates associated with Andean lineages. Our work highlights the importance of the Andean slopes in repeatedly attracting non-Andean lineages, most likely as a result of the diversity of habitats and/or host plants. Applying this analytical framework to other clades will bring important insights into the evolutionary mechanisms underlying the most species-rich biodiversity hotspot on the planet.

  9. Across the southern Andes on fin: glacial refugia, drainage reversals and a secondary contact zone revealed by the phylogeographical signal of Galaxias platei in Patagonia.

    PubMed

    Zemlak, Tyler S; Habit, Evelyn M; Walde, Sandra J; Battini, Miguel A; Adams, Emily D M; Ruzzante, Daniel E

    2008-12-01

    We employed DNA sequence variation at two mitochondrial (control region, COI) regions from 212 individuals of Galaxias platei (Pisces, Galaxiidae) collected throughout Patagonia (25 lakes/rivers) to examine how Andean orogeny and the climatic cycles throughout the Quaternary affected the genetic diversity and phylogeography of this species. Phylogenetic analyses revealed four deep genealogical lineages which likely represent the initial division of G. platei into eastern and western lineages by Andean uplift, followed by further subdivision of each lineage into separate glacial refugia by repeated Pleistocene glacial cycles. West of the Andes, refugia were likely restricted to the northern region of Patagonia with small relicts in the south, whereas eastern refugia appear to have been much larger and widespread, consisting of separate northern and southern regions that collectively spanned most of Argentinean Patagonia. The retreat of glacial ice following the last glacial maximum allowed re-colonization of central Chile from nonlocal refugia from the north and east, representing a region of secondary contact between all four glacial lineages. Northwestern glacial relicts likely followed pro-glacial lakes into central Chilean Patagonia, whereas catastrophic changes in drainage direction (Atlantic --> Pacific) for several eastern palaeolakes were the likely avenues for invasions from the east. These mechanisms, combined with evidence for recent, rapid and widespread population growth could explain the extensive contemporary distribution of G. platei throughout Patagonia.

  10. Large slope failures in the La Paz basin, Bolivian Andes

    NASA Astrophysics Data System (ADS)

    Roberts, N. J.; Hermanns, R. L.; Rabus, B.; Guzmán, M. A.; Minaya, E.; Clague, J. J.

    2014-12-01

    The La Paz basin in the eastern Bolivian Andes has been a hotspot for large-scale, deep-seated gravitational slope deformation during the Holocene. In less than 2 Ma, a network of steep-sided valleys up to 800 m deep formed in sediments of the Altiplano Plateau and underlying basement rocks. We characterize the distribution, extent, mechanisms, and modern activity of large-scale failures within this landscape using optical image interpretation, existing geologic maps, synthetic RADAR interferometry (InSAR), and field investigation. Deposits of nearly 20 landslides larger than 100 Mm3 occur within the basin. Most failures have occurred in weakly lithified Late Miocene to Pliocene sedimentary rocks and include earth flows, translational and rotational landslides, and plug flows. Failures in underlying tectonized Paleozoic sedimentary rocks include bedding-parallel rockslides. The largest failure is the 3 km3 Achcocalla earth flow (ca. 11 ka BP), which ran out ~20 km. Other dated events span the period from the early Holocene to nearly the Colonial historic period. InSAR results show that many large slope failures, including the Achocalla earth flow, are currently moving at rates of a few centimeters to a few decimeters per year. Rapid deposition, shallow burial, and rapid incision of the basin fills produced steep slopes in weak geologic materials that, coupled with groundwater discharge from the valley walls, are the primary controls on instability. In contrast, the Altiplano surface has changed little in 2 Ma and the adjacent slopes of the Cordilleran Real, although steep, are relatively stable. Of the over 100 landslides that have occurred in the city of La Paz since the early twentieth century, most are at the margins of large, deep-seated prehistoric failures, and two of the most damaging historic landslides (Hanko-Hanko, 1582; Pampahasi, 2011) were large-scale reactivations of previously failed slopes. Improved understanding of large, deep-seated landslides in

  11. Northwestern Mexico as photographed from Skylab

    NASA Technical Reports Server (NTRS)

    1975-01-01

    An oblique view of northwestern Mexico (30.0N, 113.5W), as photographed from the Skylab space station in Earth orbit by one of the Skylab 4 crewmen. This photograph was taken on a seep down the coast to document the fault patterns of southern California and northwest Mexico. The specific reason for the picture was to see of the Agua Blanca Fault in Baja California extends to the east toward the Gulf of California. No such extension was found. The fault appeard to disappear into an area of sand and heavily eroded material that obscured any feature that might be present deeper. This area of sand and loose material is the light-colored area in the center of Baja at the extreme north part of the photograph.

  12. The Northwestern University Neuroimaging Data Archive (NUNDA)

    PubMed Central

    Alpert, Kathryn; Kogan, Alexandr; Parrish, Todd; Marcus, Daniel; Wang, Lei

    2015-01-01

    The Northwestern University Neuroimaging Data Archive (NUNDA), an XNAT-powered data archiving system, aims to facilitate secure data storage; centralized data management; automated, standardized data processing; and simple, intuitive data sharing. NUNDA is a federated data archive, wherein individual project owners regulate access to their data. NUNDA supports multiple methods of data import, enabling data collection in a central repository. Data in NUNDA are available by project to any authorized user, allowing coordinated data management and review across sites. With NUNDA pipelines, users capitalize on existing procedures or standardize custom routines for consistent, automated data processing. NUNDA can be integrated with other research databases to simplify data exploration and discovery. And data on NUNDA can be confidently shared for secure collaboration. PMID:26032888

  13. The Ubiquitin Proteasome System Plays a Role in Venezuelan Equine Encephalitis Virus Infection

    PubMed Central

    Amaya, Moushimi; Keck, Forrest; Lindquist, Michael; Voss, Kelsey; Scavone, Lauren; Kehn-Hall, Kylene; Roberts, Brian; Bailey, Charles; Schmaljohn, Connie; Narayanan, Aarthi

    2015-01-01

    Many viruses have been implicated in utilizing or modulating the Ubiquitin Proteasome System (UPS) to enhance viral multiplication and/or to sustain a persistent infection. The mosquito-borne Venezuelan equine encephalitis virus (VEEV) belongs to the Togaviridae family and is an important biodefense pathogen and select agent. There are currently no approved vaccines or therapies for VEEV infections; therefore, it is imperative to identify novel targets for therapeutic development. We hypothesized that a functional UPS is required for efficient VEEV multiplication. We have shown that at non-toxic concentrations Bortezomib, a FDA-approved inhibitor of the proteasome, proved to be a potent inhibitor of VEEV multiplication in the human astrocytoma cell line U87MG. Bortezomib inhibited the virulent Trinidad donkey (TrD) strain and the attenuated TC-83 strain of VEEV. Additional studies with virulent strains of Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus (WEEV) demonstrated that Bortezomib is a broad spectrum inhibitor of the New World alphaviruses. Time-of-addition assays showed that Bortezomib was an effective inhibitor of viral multiplication even when the drug was introduced many hours post exposure to the virus. Mass spectrometry analyses indicated that the VEEV capsid protein is ubiquitinated in infected cells, which was validated by confocal microscopy and immunoprecipitation assays. Subsequent studies revealed that capsid is ubiquitinated on K48 during early stages of infection which was affected by Bortezomib treatment. This study will aid future investigations in identifying host proteins as potential broad spectrum therapeutic targets for treating alphavirus infections. PMID:25927990

  14. Needle coke and carbon fiber production from Venezuelan oil residues. (Volumes I and II)

    SciTech Connect

    Rodriguez, J.

    1992-01-01

    The conversion of high boiling petroleum residues to carbonaceous materials is investigated. A new integrated approach is presented in which Nuclear Magnetic Resonance (NMR) spectroscopy, optical microscopy, physico-chemical separations, and pilot plant operations are combined to better understand the carbonization process and to develop criteria for prediction of product quality. This methodology is applied to several Venezuelan oil residues obtained from refinery and pilot plant operations to evaluate their potential for producing high value carbon products such as needle coke and carbon fibers. Feedstocks, reaction intermediates, and products are characterized by [sup 1]H and [sup 13]C NMR in terms of basic hydrocarbon constituents, and changes in carbon and proton distributions are measured. The extent of aromatization and other structural changes resulting from thermal cracking reactions are calculated for the first time by combining pilot plant data with NMR spectroscopic data in both the liquid and solid states. Improved methods for interpreting NMR data of liquid and solid materials from petroleum residues are developed. The effects of operating conditions and the role of different fractions obtained by distillation, n-pentane extraction and high performance liquid chromatography during reaction are documented. Delayed coking and thermal cracking pilot plant experiments were designed and carried out to simulate refinery operation and to provide samples for further characterization. Representative samples of coke were evaluated for use as electrodes in electric arc furnaces. It is shown that by proper selection of feedstock and operational parameters, premium quality needle cokes can be produced. A laboratory scale melt spinning apparatus to produce continuous mesophase pitch carbon fibers was designed and built. The ability to produce thin filaments (less than 20 [mu]m diameter) from petroleum pitches was demonstrated.

  15. Venezuelan Equine Encephalitis Replicon Particles Can Induce Rapid Protection against Foot-and-Mouth Disease Virus

    PubMed Central

    Diaz-San Segundo, Fayna; Dias, Camila C. A.; Moraes, Mauro P.; Weiss, Marcelo; Perez-Martin, Eva; Owens, Gary; Custer, Max; Kamrud, Kurt; de los Santos, Teresa

    2013-01-01

    We have previously shown that delivery of the porcine type I interferon gene (poIFN-α/β) with a replication-defective human adenovirus vector (adenovirus 5 [Ad5]) can sterilely protect swine challenged with foot-and-mouth disease virus (FMDV) 1 day later. However, the need of relatively high doses of Ad5 limits the applicability of such a control strategy in the livestock industry. Venezuelan equine encephalitis virus (VEE) empty replicon particles (VRPs) can induce rapid protection of mice against either homologous or, in some cases, heterologous virus challenge. As an alternative approach to induce rapid protection against FMDV, we have examined the ability of VRPs containing either the gene for green fluorescent protein (VRP-GFP) or poIFN-α (VRP-poIFN-α) to block FMDV replication in vitro and in vivo. Pretreatment of swine or bovine cell lines with either VRP significantly inhibited subsequent infection with FMDV as early as 6 h after treatment and for at least 120 h posttreatment. Furthermore, mice pretreated with either 107 or 108 infectious units of VRP-GFP and challenged with a lethal dose of FMDV 24 h later were protected from death. Protection was induced as early as 6 h after treatment and lasted for at least 48 h and correlated with induction of an antiviral response and production of IFN-α. By 6 h after treatment several genes were upregulated, and the number of genes and the level of induction increased at 24 h. Finally, we demonstrated that the chemokine IP-10, which is induced by IFN-α and VRP-GFP, is directly involved in protection against FMDV. PMID:23468490

  16. Integrated geological model in a transect of the Eastern Venezuelan Basin

    SciTech Connect

    Passalacqua, H.; Gou, I. ); Truskowski, I.; Di Croce, J. )

    1992-01-01

    The generation, migration and accumulation of hydrocarbons are among the most controversial problems of petroleum exploration in platform and, more especially, complex areas such as thrusted zones. The understanding of these phenomena is essential for the explorationist and is facilitated with the use of mathematical models which enable the integration and assimilation of parameters varying with time and space. In order to carry out this mathematical model an integrated synthesis is necessary. It should include stratigraphic, structural, reservoir and geochemical data. The elaboration of a geological model along a transect in the Eastern Venezuelan Basin was conducted to prepare data for the mathematical modeling application. The main results of the synthesis are: The elaboration of a reliable stratigraphic model including updated ages. A coherent structural interpretation in thrusted zones, validated by the balancing of North-South cross sections. The most relevant findings are: The identification of out-of-sequence thrusts and the involvement of the Upper Crust in the deformation processes. The elaboration of reservoir and hydrodynamic models which point out the importance of the major reservoirs. A characterization of the three different source-rocks of marine and continental origin in the Guayuta Group and Carapita Formation and the comprehension of their maturity, expulsion and migration processes with regards to the structural history. In this way the generation of 1,350 to 3,300 [times] 10[sup 9] barrels of oil has been estimated, of which 6 to 15 percent have been recognized within the transect. The final mathematical modeling, with the input of these synthetical data will be carried out with the use of the available software in the platform area. New software is presently being developed for thrusted areas.

  17. A multisystem approach for development and evaluation of inactivated vaccines for Venezuelan equine encephalitis virus (VEEV).

    PubMed

    Fine, Donald L; Jenkins, Erin; Martin, Shannon S; Glass, Pamela; Parker, Michael D; Grimm, Brad

    2010-02-01

    A multisystem approach was used to assess the efficiency of several methods for inactivation of Venezuelan equine encephalitis virus (VEEV) vaccine candidates. A combination of diverse assays (plaque, in vitro cytopathology and mouse neurovirulence) was used to verify virus inactivation, along with the use of a specific ELISA to measure retention of VEEV envelope glycoprotein epitopes in the development of several inactivated VEEV candidate vaccines derived from an attenuated strain of VEEV (V3526). Incubation of V3526 aliquots at temperatures in excess of 64 degrees C for periods >30 min inactivated the virus, but substantially reduced VEEV specific monoclonal antibody binding of the inactivated material. In contrast, V3526 treated either with formalin at concentrations of 0.1% or 0.5% (v/v) for 4 or 24 h, or irradiated with 50 kGy gamma radiation rendered the virus non-infectious while retaining significant levels of monoclonal antibody binding. Loss of infectivity of both the formalin inactivated (fV3526) and gamma irradiated (gV3526) preparations was confirmed via five successive blind passages on BHK-21 cells. Similarly, loss of neurovirulence for fV3526 and gV3526 was demonstrated via intracerebral inoculation of suckling BALB/c mice. Excellent protection against subcutaneous challenge with VEEV IA/B Trinidad donkey strain was demonstrated using a two dose immunization regimen with either fV3526 or gV3526. The combination of in vitro and in vivo assays provides a practical approach to optimize manufacturing process parameters for development of other inactivated viral vaccines.

  18. Genetic and evolutionary characterization of Venezuelan equine encephalitis virus isolates from Argentina.

    PubMed

    Pisano, María Belén; Torres, Carolina; Ré, Viviana Elizabeth; Farías, Adrián Alejandro; Sánchez Seco, María Paz; Tenorio, Antonio; Campos, Rodolfo; Contigiani, Marta Silvia

    2014-08-01

    Venezuelan equine encephalitis viruses (VEEV) are emerging pathogens of medical and veterinary importance circulating in America. Argentina is a country free from epizootic VEEV activity, with circulation of enzootic strains belonging to Rio Negro virus (RNV; VEEV subtype VI) and Pixuna virus (PIXV, VEEV subtype IV). In this work, we aim to report the sequencing and phylogenetic analyses of all Argentinean VEE viruses, including 7 strains previously isolated from mosquitoes in 1980, 5 sequences obtained from rodents in 1991 and 11 sequences amplified from mosquitoes between 2003 and 2005. Two genomic regions, corresponding to the non-structural protein 4 (nsP4) and the protein E3/E2 (PE2) genes were analyzed, but only 8 samples could be amplified in the last one (longer and more variable fragment of 702 bp). For both genomic fragments, phylogenetic trees showed the absence of lineages within RNV group, and a close genetic relationship between Argentinean strains and the prototype strain BeAr35645 for PIXV clade. The analysis of nsP4 gene opens the possibility to propose a possible geographic clustering of strains within PIXV group (Argentina and Brazil). Coalescent analysis performed on RNV sequences suggested a common ancestor of 58.3 years (with a 95% highest posterior density [HPD] interval of 16.4-345.7) prior to 1991 and inferred a substitution rate of 9.8×10(-5)substitutions/site/year, slightly lower than other enzootic VEE viruses. These results provide, for the first time, information about genetic features and variability of all VEEVs detected in Argentina, creating a database that will be useful for future detections in our country. This is particularly important for RNV, which has indigenous circulation.

  19. Potential Sources of the 1995 Venezuelan Equine Encephalitis Subtype IC Epidemic

    PubMed Central

    Brault, Aaron C.; Powers, Ann M.; Medina, Gladys; Wang, Eryu; Kang, Wenli; Salas, Rosa Alba; De Siger, Julieta; Weaver, Scott C.

    2001-01-01

    Venezuelan equine encephalitis viruses (VEEV) belonging to subtype IC have caused three (1962–1964, 1992–1993 and 1995) major equine epizootics and epidemics. Previous sequence analyses of a portion of the envelope glycoprotein gene demonstrated a high degree of conservation among isolates from the 1962–1964 and the 1995 outbreaks, as well as a 1983 interepizootic mosquito isolate from Panaquire, Venezuela. However, unlike subtype IAB VEEV that were used to prepare inactivated vaccines that probably initiated several outbreaks, subtype IC viruses have not been used for vaccine production and their conservation cannot be explained in this way. To characterize further subtype IC VEEV conservation and to evaluate potential sources of the 1995 outbreak, we sequenced the complete genomes of three isolates from the 1962–1964 outbreak, the 1983 Panaquire interepizootic isolate, and two isolates from 1995. The sequence of the Panaquire isolate, and that of virus isolated from a mouse brain antigen prepared from subtype IC strain P676 and used in the same laboratory, suggested that the Panaquire isolate represents a laboratory contaminant. Some authentic epizootic IC strains isolated 32 years apart showed a greater degree of sequence identity than did isolates from the same (1962–1964 or 1995) outbreak. If these viruses were circulating and replicating between 1964 and 1995, their rate of sequence evolution was at least 10-fold lower than that estimated during outbreaks or that of closely related enzootic VEEV strains that circulate continuously. Current understanding of alphavirus evolution is inconsistent with this conservation. This subtype IC VEEV conservation, combined with phylogenetic relationships, suggests the possibility that the 1995 outbreak was initiated by a laboratory strain. PMID:11390583

  20. Candidate vaccine against botulinum neurotoxin serotype A derived from a Venezuelan equine encephalitis virus vector system.

    PubMed

    Lee, J S; Pushko, P; Parker, M D; Dertzbaugh, M T; Smith, L A; Smith, J F

    2001-09-01

    A candidate vaccine against botulinum neurotoxin serotype A (BoNT/A) was developed by using a Venezuelan equine encephalitis (VEE) virus replicon vector. This vaccine vector is composed of a self-replicating RNA containing all of the VEE nonstructural genes and cis-acting elements and also a heterologous immunogen gene placed downstream of the subgenomic 26S promoter in place of the viral structural genes. In this study, the nontoxic 50-kDa carboxy-terminal fragment (H(C)) of the BoNT/A heavy chain was cloned into the replicon vector (H(C)-replicon). Cotransfection of BHK cells in vitro with the H(C)-replicon and two helper RNA molecules, the latter encoding all of the VEE structural proteins, resulted in the assembly and release of propagation-deficient, H(C) VEE replicon particles (H(C)-VRP). Cells infected with H(C)-VRP efficiently expressed this protein when analyzed by either immunofluorescence or by Western blot. To evaluate the immunogenicity of H(C)-VRP, mice were vaccinated with various doses of H(C)-VRP at different intervals. Mice inoculated subcutaneously with H(C)-VRP were protected from an intraperitoneal challenge of up to 100,000 50% lethal dose units of BoNT/A. Protection correlated directly with serum enzyme-linked immunosorbent assay titers to BoNT/A. The duration of the immunity achieved was tested at 6 months and at 1 year postvaccination, and mice challenged at these times remained refractory to challenge with BoNT/A.

  1. The ubiquitin proteasome system plays a role in venezuelan equine encephalitis virus infection.

    PubMed

    Amaya, Moushimi; Keck, Forrest; Lindquist, Michael; Voss, Kelsey; Scavone, Lauren; Kehn-Hall, Kylene; Roberts, Brian; Bailey, Charles; Schmaljohn, Connie; Narayanan, Aarthi

    2015-01-01

    Many viruses have been implicated in utilizing or modulating the Ubiquitin Proteasome System (UPS) to enhance viral multiplication and/or to sustain a persistent infection. The mosquito-borne Venezuelan equine encephalitis virus (VEEV) belongs to the Togaviridae family and is an important biodefense pathogen and select agent. There are currently no approved vaccines or therapies for VEEV infections; therefore, it is imperative to identify novel targets for therapeutic development. We hypothesized that a functional UPS is required for efficient VEEV multiplication. We have shown that at non-toxic concentrations Bortezomib, a FDA-approved inhibitor of the proteasome, proved to be a potent inhibitor of VEEV multiplication in the human astrocytoma cell line U87MG. Bortezomib inhibited the virulent Trinidad donkey (TrD) strain and the attenuated TC-83 strain of VEEV. Additional studies with virulent strains of Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus (WEEV) demonstrated that Bortezomib is a broad spectrum inhibitor of the New World alphaviruses. Time-of-addition assays showed that Bortezomib was an effective inhibitor of viral multiplication even when the drug was introduced many hours post exposure to the virus. Mass spectrometry analyses indicated that the VEEV capsid protein is ubiquitinated in infected cells, which was validated by confocal microscopy and immunoprecipitation assays. Subsequent studies revealed that capsid is ubiquitinated on K48 during early stages of infection which was affected by Bortezomib treatment. This study will aid future investigations in identifying host proteins as potential broad spectrum therapeutic targets for treating alphavirus infections.

  2. Novel vaccine against Venezuelan equine encephalitis combines advantages of DNA immunization and a live attenuated vaccine.

    PubMed

    Tretyakova, Irina; Lukashevich, Igor S; Glass, Pamela; Wang, Eryu; Weaver, Scott; Pushko, Peter

    2013-02-04

    DNA vaccines combine remarkable genetic and chemical stability with proven safety and efficacy in animal models, while remaining less immunogenic in humans. In contrast, live-attenuated vaccines have the advantage of inducing rapid, robust, long-term immunity after a single-dose vaccination. Here we describe novel iDNA vaccine technology that is based on an infectious DNA platform and combines advantages of DNA and live attenuated vaccines. We applied this technology for vaccination against infection with Venezuelan equine encephalitis virus (VEEV), an alphavirus from the Togaviridae family. The iDNA vaccine is based on transcription of the full-length genomic RNA of the TC-83 live-attenuated virus from plasmid DNA in vivo. The in vivo-generated viral RNA initiates limited replication of the vaccine virus, which in turn leads to efficient immunization. This technology allows the plasmid DNA to launch a live-attenuated vaccine in vitro or in vivo. Less than 10 ng of pTC83 iDNA encoding the full-length genomic RNA of the TC-83 vaccine strain initiated replication of the vaccine virus in vitro. In order to evaluate this approach in vivo, BALB/c mice were vaccinated with a single dose of pTC83 iDNA. After vaccination, all mice seroconverted with no adverse reactions. Four weeks after immunization, animals were challenged with the lethal epidemic strain of VEEV. All iDNA-vaccinated mice were protected from fatal disease, while all unvaccinated controls succumbed to infection and died. To our knowledge, this is the first example of launching a clinical live-attenuated vaccine from recombinant plasmid DNA in vivo.

  3. Petroleum in the Junggar basin, northwestern China

    NASA Astrophysics Data System (ADS)

    Taner, Irfan; Kamen-Kaye, Maurice; Meyerhoff, Arthur A.

    The Junggar basin occupies a large triangular area of some 130 000 km 2 in northwestern China. Situated between the Altay Shan (Altay Range) on the northeast and the Tian Shan (Tian Range) on the southwest, and between lesser ranges around the remainder of its periphery, the Junggar basin is completely intermontane. Its history as a basin began in the Permian, and continued as various uplifts and downwarps evolved. Through the Paleozoic the characteristics of the Junggar basin area were largely geosynclinal and marine. Its post-Permian development took place exclusively in continental regimes. Inhabitants of the Junggar basin have known and utilized its numerous oil and asphalt seeps and its spectacular spreads of asphalt for more than 2000 years, especially in the Karamay-Urho thrust belt near the northwestern rim. The first discovery of oil in the modern sense came at Dushanzi, one of the steeply folded anticlines of theÜrümqi foredeep near the southern rim. The first shallow oil in the Karamay-Urho thrust belt came in 1937, followed by commercial production in the Karamay field in 1955. Output continued to be modest until wells were drilled through local thrusts and reverse faults in the early 1980s. By 1985, cumulative production of the Karamay group of fields had reached 42,000,000 t (metric tonnes) (306,000,000 bbl), with a calculated minimum ultimate recovery of 280,000,000 t (2 billion bbl). Principal production comes from Permian and Triassic strata in continental facies. Apart from marine Mid and Upper Carboniferous strata, source rocks occur mainly in fine-grained lacustrine detrital beds of the Permian, the Triassic, the Jurassic and the Tertiary. Several uplifts and downwarps elsewhere in the Junggar basin remain to be drilled comprehensively. Results from such drilling may enhance the very important position that the Junggar already has attained in the hierarchy of China's onshore basins.

  4. Comparative Phylogeography Reveals Cryptic Diversity and Repeated Patterns of Cladogenesis for Amphibians and Reptiles in Northwestern Ecuador.

    PubMed

    Arteaga, Alejandro; Pyron, R Alexander; Peñafiel, Nicolás; Romero-Barreto, Paulina; Culebras, Jaime; Bustamante, Lucas; Yánez-Muñoz, Mario H; Guayasamin, Juan M

    2016-01-01

    Comparative phylogeography allow us to understand how shared historical circumstances have shaped the formation of lineages, by examining a broad spectrum of co-distributed populations of different taxa. However, these types of studies are scarce in the Neotropics, a region that is characterized by high diversity, complex geology, and poorly understood biogeography. Here, we investigate the diversification patterns of five lineages of amphibians and reptiles, co-distributed across the Choco and Andes ecoregions in northwestern Ecuador. Mitochondrial DNA and occurrence records were used to determine the degree of geographic genetic divergence within species. Our results highlight congruent patterns of parapatric speciation and common geographical barriers for distantly related taxa. These comparisons indicate similar biological and demographic characteristics for the included clades, and reveal the existence of two new species of Pristimantis previously subsumed under P. walkeri, which we describe herein. Our data supports the hypothesis that widely distributed Chocoan taxa may generally experience their greatest opportunities for isolation and parapatric speciation across thermal elevational gradients. Finally, our study provides critical information to predict which unstudied lineages may harbor cryptic diversity, and how geology and climate are likely to have shaped their evolutionary history.

  5. Comparative Phylogeography Reveals Cryptic Diversity and Repeated Patterns of Cladogenesis for Amphibians and Reptiles in Northwestern Ecuador

    PubMed Central

    Pyron, R. Alexander; Peñafiel, Nicolás; Romero-Barreto, Paulina; Culebras, Jaime; Bustamante, Lucas; Yánez-Muñoz, Mario H.; Guayasamin, Juan M.

    2016-01-01

    Comparative phylogeography allow us to understand how shared historical circumstances have shaped the formation of lineages, by examining a broad spectrum of co-distributed populations of different taxa. However, these types of studies are scarce in the Neotropics, a region that is characterized by high diversity, complex geology, and poorly understood biogeography. Here, we investigate the diversification patterns of five lineages of amphibians and reptiles, co-distributed across the Choco and Andes ecoregions in northwestern Ecuador. Mitochondrial DNA and occurrence records were used to determine the degree of geographic genetic divergence within species. Our results highlight congruent patterns of parapatric speciation and common geographical barriers for distantly related taxa. These comparisons indicate similar biological and demographic characteristics for the included clades, and reveal the existence of two new species of Pristimantis previously subsumed under P. walkeri, which we describe herein. Our data supports the hypothesis that widely distributed Chocoan taxa may generally experience their greatest opportunities for isolation and parapatric speciation across thermal elevational gradients. Finally, our study provides critical information to predict which unstudied lineages may harbor cryptic diversity, and how geology and climate are likely to have shaped their evolutionary history. PMID:27120100

  6. [Medical education at Universidad de los Andes, Santiago, Chile].

    PubMed

    Orrego Vicuña, F

    1997-07-01

    Universidad de los Andes School of Medicine started in 1991 with a new medical curriculum aimed at providing a medical education for its students, that is, it attempts to give, together with technical proficiency in medical matters, formation of character and a strong ethical attitude. The curriculum lasts for seven years: five of basic, pre-clinical and clinical theoretical and practical courses, followed by two years of internships in Internal Medicine, Surgery, Obstetrics and Pediatrics, plus a four month period of an elective internship. The courses have an integrated design, in which each matter is presented from multiple perspectives, e.g. in Internal Medicine together with the clinical aspects of disease, the pathophysiology and the pharmacology of the drugs used are presented. Also the Pathology of each disease is given in coordination in the Pathology course. General educational matters such as Anthropology, Psychology, Origin of Living Beings, Theology and Medical Ethics are interspersed in the curriculum. An important feature is the personal counselling system, in which each student may choose an academic counsellor and discuss with him (her) the subjects of his choosing. Clinical practice is given in a system that includes five hospitals and five private clinics that range from general medical practice to Psychiatry or Ophthalmology.

  7. Membrane triangles with corner drilling freedoms. II - The ANDES element

    NASA Technical Reports Server (NTRS)

    Felippa, Carlos A.; Militello, Carmelo

    1992-01-01

    This is the second article in a three-part series on the construction of 3-node, 9-dof membrane elements with normal-to-its-plane rotational freedoms (the so-called drilling freedoms) using parametrized variational principles. In this part, one such element is derived within the context of the assumed natural deviatoric strain (ANDES) formulation. The higher-order strains are obtained by constructing three parallel-to-sides pure-bending modes from which natural strains are obtained at the corner points and interpolated over the element. To attain rank sufficiency, an additional higher-order 'torsional' mode, corresponding to equal hierarchical rotations at each corner with all other motions precluded, is incorporated. The resulting formulation has five free parameters. When these parameters are optimized against pure bending by energy balance methods, the resulting element is found to coalesce with the optimal EFF element derived in Part I. Numerical integration as a strain filtering device is found to play a key role in this achievement.

  8. Meteorological Conditions of Floods In The Chilean Andes Mountains

    NASA Astrophysics Data System (ADS)

    Vergara, J.

    Catastrophic floods occurred on mountains River during 2000 and 2001. The meteo- rological conditions of flood during the last five years have analyzed. For example, the flood of June 29 of 2000 occurred after one of extremely wettest June of the last 40 years were snowfall was 991cm in the Aconcagua Valley. Infrequently storms activ- ity generated a huge snowfall and rainfall over the Andes mountains on June of 2000 (1525mm in El Maule Valley) and the end of the unusually period, the flood was trig- gered by rising temperatures on the mountains and heavy rain (199mm in 24 hours) fall over the fresh snow on the morning of June 29 and floods wave developed and moved down along of the all river located on Central part of Chile, the foods peak was 2970.5m3/s on the El Maule basin in the morning of June 29. The regional meteoro- logical models with the hydrological forecasting was used for alert of the floods.

  9. Over three millennia of mercury pollution in the Peruvian Andes

    PubMed Central

    Cooke, Colin A.; Balcom, Prentiss H.; Biester, Harald; Wolfe, Alexander P.

    2009-01-01

    We present unambiguous records of preindustrial atmospheric mercury (Hg) pollution, derived from lake-sediment cores collected near Huancavelica, Peru, the largest Hg deposit in the New World. Intensive Hg mining first began ca. 1400 BC, predating the emergence of complex Andean societies, and signifying that the region served as a locus for early Hg extraction. The earliest mining targeted cinnabar (HgS) for the production of vermillion. Pre-Colonial Hg burdens peak ca. 500 BC and ca. 1450 AD, corresponding to the heights of the Chavín and Inca states, respectively. During the Inca, Colonial, and industrial intervals, Hg pollution became regional, as evidenced by a third lake record ≈225 km distant from Huancavelica. Measurements of sediment-Hg speciation reveal that cinnabar dust was initially the dominant Hg species deposited, and significant increases in deposition were limited to the local environment. After conquest by the Inca (ca. 1450 AD), smelting was adopted at the mine and Hg pollution became more widely circulated, with the deposition of matrix-bound phases of Hg predominating over cinnabar dust. Our results demonstrate the existence of a major Hg mining industry at Huancavelica spanning the past 3,500 years, and place recent Hg enrichment in the Andes in a broader historical context. PMID:19451629

  10. Structural style on southern flank of Merida Andes, Venezuela

    SciTech Connect

    Urbina, C.; Cornelio, A. )

    1993-02-01

    The Merida Andes exhibit the most complex tectonics in western Venezuela. By studying the different ages and regional distribution of rocks, we can describe some tectonic features which are of interest to oil exploration in this area. Vertical basement movements accompanied extensional tectonics from pre-Cambrian until Eocene times. For this time interval, we reconstructed diverse normal fault systems and associated subsidence. From Eocene time onwards, compressional tectonics gave origin to anticlines and reverse, thrust and back-thrust faults. Neo-tectonic movements have modified existing structures by dislocation along transcurrent fault systems. Geochemical analyses have determined the presence of hydrocarbon source rocks equivalent to the a Luna Formation of the Maracaibo Basin; seismic, surface and subsurface data prove the existence of excellent seals in the Eocene Paguey Shale. The principal problem is to determine the timing of hydrocarbon migration with respect to the timing of trap formation. It is highly probable that the sapropelic strata of the Navay Formation, equivalent to the La Luna Formation, is presently expelling hydrocarbons to traps in the Barinas Basin, under presently existing temperature-pressure conditions.

  11. Epidemiology of Echinococcus granulosus infection in the central Peruvian Andes.

    PubMed Central

    Moro, P. L.; McDonald, J.; Gilman, R. H.; Silva, B.; Verastegui, M.; Malqui, V.; Lescano, G.; Falcon, N.; Montes, G.; Bazalar, H.

    1997-01-01

    The prevalence of human, canine, and ovine echinococcosis was determined in an endemic area of the Peruvian Andes where control programmes have not been operational since 1980. Prevalence of infection in humans was determined using portable ultrasound, chest X-rays, and an enzyme-linked immunoelectrotransfer blot (EITB) assay. Canine and ovine echinococcal prevalence was determined by microscopic stool examinations following arecoline purging for tapeworm detection and by examination of the viscera from slaughtered livestock animals, respectively. The prevalence among 407 humans surveyed was 9.1%. The frequency of disease in the liver, lung, and in both organs was 3.4%, 2.0%, and 0.2%, respectively. Portable ultrasound or portable chest X-ray has shown that, compared to adults, children under 11 years had significantly higher seropositive rates without evidence of hydatid disease (P < 0.05). Among the 104 dogs inspected for echinococcus after arecoline purging, 33 (32%) were positive for adult tapeworms. Among the 117 sheep slaughtered at the local abattoir, 102 (87%) had hydatid cysts. The prevalence of human hydatidosis in this endemic area of Peru is one of the highest in the world and nearly five times higher than previously reported in 1980. An increase in echinococcosis prevalence may result after premature cessation of control programmes. PMID:9509628

  12. Quaternary Glaciations in the Rio Mendoza Valley, Argentine Andes

    NASA Astrophysics Data System (ADS)

    Espizua, Lydia E.

    1993-09-01

    In the Rio Mendoza valley, five Pleistocene drifts and one Holocene drift are distinguished by multiple relative-age criteria, including surface-rock weathering, development of rock varnish, moraine morphology, soil-profile development, and stratigraphic relationships. Several absolute ages suggest a preliminary chronology. During the oldest (Uspallata) glaciation, a system of valley glaciers flowed 110 km from the Andean drainage divide and 80 km from Cerro Aconcagua to terminate at 1850 m. Drift of this ice advance is older than a widespread tephra dated by fission-track at 360,000 ± 36,000 yr. During the Punta de Vacas advance, ice terminated at 2350 m, while during the subsequent Penitentes advance, the glacier system ended at 2500 m. A travertine layer overlying Penitentes Drift has U-series age of 24,200 ± 2000 yr B.P. The distribution of Horcones Drift, which is inferred to represent the last glacial maximum, delimits an independent ice stream that flowed 22 km down Horcones valley to 2750 m. A later readvance (Almacenes) reached 3250 m. Confluencia Drift is considered to be Neoglacial in age and extends downvalley to 3300 m. The moraine sequence is compared with those studied by Caviedes (1972) along Rio Aconcagua on the Chilean flank of the Andes.

  13. The Grenville-age basement of the Andes

    NASA Astrophysics Data System (ADS)

    Ramos, Victor A.

    2010-01-01

    The analysis of the basement of the Andes shows the strong Grenville affinities of most of the inliers exposed in the different terranes from Colombia to Patagonia. The terranes have different histories, but most of them participated in the Rodinia supercontinent amalgamation during the Mesoproterozoic between 1200 and 1000 Ma. After Rodinia break-up some terranes were left in the Laurentian side such as Cuyania and Chilenia, while others stayed in the Gondwanan side. Some of the terranes once collided with the Amazon craton remained attached, experiencing diverse rifting episodes all along the Phanerozoic, as the Arequipa and Pampia terranes. Some other basement inliers were detached in the Neoproterozoic and amalgamated again to Gondwana in the Early Cambrian, Middle Ordovician or Permian times. A few basement inliers with Permian metamorphic ages were transferred to Gondwana after Pangea break-up from the Laurentian side. Some of them were part of the present Middle America terrane. An exceptional case is the Oaxaquia terrane that was detached from the Gondwana margin after the Early Ordovician and is now one of the main Mexican terranes that collided with Laurentia. These displacements, detachments, and amalgamations indicate a complex terrane transfer between Laurentia and Gondwana during Paleozoic times, following plate reorganizations and changes in the absolute motion of Gondwana.

  14. Characteristics of Precipitation Features and Annual Rainfall during the TRMM Era in the Central Andes

    NASA Technical Reports Server (NTRS)

    Mohr, Karen I.; Slayback, Daniel; Yager, Karina

    2014-01-01

    The central Andes extends from 7 deg to 21 deg S, with its eastern boundary defined by elevation (1000m and greater) and its western boundary by the coastline. The authors used a combination of surface observations, reanalysis, and the University of Utah Tropical Rainfall Measuring Mission (TRMM) precipitation features (PF) database to understand the characteristics of convective systems and associated rainfall in the central Andes during the TRMM era, 1998-2012. Compared to other dry (West Africa), mountainous (Himalayas), and dynamically linked (Amazon) regions in the tropics, the central Andes PF population was distinct from these other regions, with small and weak PFs dominating its cumulative distribution functions and annual rainfall totals. No more than 10% of PFs in the central Andes met any of the thresholds used to identify and define deep convection (minimum IR cloud-top temperatures, minimum 85-GHz brightness temperature, maximum height of the 40-dBZ echo). For most of the PFs, available moisture was limited (less than 35mm) and instability low (less than 500 J kg(exp -1)). The central Andes represents a largely stable, dry to arid environment, limiting system development and organization. Hence, primarily short-duration events (less than 60 min) characterized by shallow convection and light to light-moderate rainfall rates (0.5-4.0 mm h(exp -1)) were found.

  15. General view of National Cemetery at former Northwestern Branch of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of National Cemetery at former Northwestern Branch of the National Home for Disabled Volunteer Soldiers. View looking southeast from intersection of American War Mothers and Juneau Avenues. - Wood National Cemetery, 5000 West National Avenue, Milwaukee, Milwaukee County, WI

  16. 15. INTERIOR, NORTHWESTERN WING, SHOW ROOM, DETAIL OF BALCONY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. INTERIOR, NORTHWESTERN WING, SHOW ROOM, DETAIL OF BALCONY - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  17. 14. INTERIOR, NORTHWESTERN WING, SHOW ROOM, DETAIL OF FIREPLACE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. INTERIOR, NORTHWESTERN WING, SHOW ROOM, DETAIL OF FIREPLACE - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  18. Anaerobic thermophilic bacteria isolated from a Venezuelan oil field and its potential use in microbial improved oil recovery

    SciTech Connect

    Trebbau, G.; Fernandez, B.; Marin, A.

    1995-12-31

    The objective of this work is to determine the ability of indigenous bacteria from a Venezuelan oil field to grow under reservoir conditions inside a porous media, and to produce metabolites capable of recovering residual crude oil. For this purpose, samples of formation waters from a central-eastern Venezuelan oil reservoir were enriched with different carbon sources and a mineral basal media. Formation water was used as a source of trace metals. The enrichments obtained were incubated at reservoir temperature (71{degrees}C), reservoir pressure (1,200 psi), and under anaerobic conditions for both outside and inside porous media (Berea core). Growth and metabolic activity was followed outside porous media by measuring absorbance at 660 nm, increases in pressure, and decreases in pH. Inside porous media bacterial activity was determined by visual examination of the produced waters (gas bubbles and bacterial cells). All the carbohydrates tested outside porous media showed good growth at reservoir conditions. The pH was lowered, gases such as CO{sub 2} and CH{sub 4} were identified by GC. Surface tension was lowered in some enrichments by 30% when compared to controls. Growth was decreased inside porous media, but gases were produced and helped displace oil. In addition, 10% residual oil was recovered from the Berea core. Mathematical modeling was applied to the laboratory coreflood experiment to evaluate the reproducibility of the results obtained.

  19. Epidemiological modeling and risk analysis of Venezuelan Equine Encephalitis in the human population of Coastal Chiapas, Mexico in 2007-2009

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analysis of 101 febrile illness patients sero positive for Venezuelan equine encephalitis (VEEV) was carried out in a retrospective study along 18 municipalities and endemic VEEV pacific coastal regions of the State of Chiapas in southern Mexico. Geographic information systems (GIS), satellite imag...

  20. Structure and tectonic evolution of the Fuegian Andes (southernmost South America) in the framework of the Scotia Arc development

    NASA Astrophysics Data System (ADS)

    Torres Carbonell, Pablo J.; Dimieri, Luis V.; Olivero, Eduardo B.; Bohoyo, Fernando; Galindo-Zaldívar, Jesús

    2014-12-01

    The major structural and tectonic features of the Fuegian Andes provide an outstanding onshore geological framework that aids in the understanding of the tectonic evolution of the Scotia Arc, mainly known from offshore studies. The orogenic history of the Fuegian Andes (Late Cretaceous-Miocene) is thus compared and integrated with the tectonic history of the Scotia Sea. Late Cretaceous-Paleocene structures in the Fuegian Andes suggest a N-directed contraction consistent with an oroclinal bending of the southernmost South America-Antarctic Peninsula continental bridge. This N-directed contraction in the Fuegian Andes continued during the spreading of the West Scotia Ridge, between 40-50 and 10 Ma ago. The onset of major strike-slip faulting in Tierra del Fuego is considered here to be not older than the late Miocene, consistent with the recent history of the North Scotia Ridge; thus forming part of a tectonic regime superposed to the prior contraction in the Fuegian Andes.

  1. Traditional use of the Andean flicker (Colaptes rupicola) as a galactagogue in the Peruvian Andes

    PubMed Central

    Froemming, Steve

    2006-01-01

    This paper explores the use of the dried meat and feathers of the Andean Flicker (Colaptes rupicola) to increase the milk supply of nursing women and domestic animals in the Andes. The treatment is of preColumbian origin, but continues to be used in some areas, including the village in the southern Peruvian highlands where I do ethnographic research. I explore the factors giving rise to and sustaining the practice, relate it to other galactagogues used in the Andes and to the use of birds in ethnomedical and ethnoveterinary treatments in general, and situate it within the general tendency in the Andes and elsewhere to replicate human relations in the treatment of valuable livestock. The bird's use as a galactagogue appears to be motivated by both metaphorical associations and its perceived efficacy, and conceptually blends human and animal healthcare domains. PMID:16677398

  2. Cenozoic climate change as a possible cause for the rise of the Andes.

    PubMed

    Lamb, Simon; Davis, Paul

    2003-10-23

    Causal links between the rise of a large mountain range and climate have often been considered to work in one direction, with significant uplift provoking climate change. Here we propose a mechanism by which Cenozoic climate change could have caused the rise of the Andes. Based on considerations of the force balance in the South American lithosphere, we suggest that the height of, and tectonics in, the Andes are strongly controlled both by shear stresses along the plate interface in the subduction zone and by buoyancy stress contrasts between the trench and highlands, and shear stresses in the subduction zone depend on the amount of subducted sediments. We propose that the dynamics of subduction and mountain-building in this region are controlled by the processes of erosion and sediment deposition, and ultimately climate. In central South America, climate-controlled sediment starvation would then cause high shear stress, focusing the plate boundary stresses that support the high Andes.

  3. Carbon stabilization mechanisms in soils in the Andes

    NASA Astrophysics Data System (ADS)

    Jansen, Boris; Cammeraat, Erik

    2015-04-01

    The volcanic ash soils of the Andes contain very large stocks of soil organic matter (SOM) per unit area. Consequently, they constitute significant potential sources or sinks of the greenhouse gas CO2. Climate and/or land use change potentially have a strong effect on these large SOM stocks. To clarify the role of chemical and physical stabilisation mechanisms in volcanic ash soils in the montane tropics, we investigated carbon stocks and stabilization mechanisms in the top- and subsoil along an altitudinal transect in the Ecuadorian Andes. The transect encompassed a sequence of paleosols under forest and grassland (páramo), including a site where vegetation cover changed in the last century. We applied selective extraction techniques, performed X-ray diffraction analyses of the clay fraction and estimated pore size distributions at various depths in the top- and subsoil along the transect. In addition, from several soils the molecular composition of SOM was further characterized with depth in the current soil as well as the entire first and the top of the second paleosol using GC/MS analyses of extractable lipids and Pyrolysis-GC/MS analyses of bulk organic matter. Our results show that organic carbon stocks in the mineral soil under forest a páramo vegetation were roughly twice as large as global averages for volcanic ash soils, regardless of whether the first 30cm, 100cm or 200cm were considered. We found the carbon stabilization mechanisms involved to be: i) direct stabilization of SOM in organo-metallic (Al-OM) complexes; ii) indirect protection of SOM through low soil pH and toxic levels of Al; and iii) physical protection of SOM due to a very high microporosity of the soil (Tonneijck et al., 2010; Jansen et al. 2011). When examining the organic carbon at a molecular level, interestingly we found extensive degradation of lignin in the topsoil while extractable lipids were preferentially preserved in the subsoil (Nierop and Jansen, 2009). Both vegetation

  4. Possible future lakes in the Andes of Peru

    NASA Astrophysics Data System (ADS)

    Colonia, Daniel; Haeberli, Wilfried; Torres, Judith; Giraldez, Claudia; Schauwecker, Simone; Santiago, Alexzander; Cochachin, Alejo; Huggel, Christian

    2015-04-01

    Climate change has caused large losses of glacier mass in the Andes of Peru. Also, given the projected changes in climate, based on different IPCC scenarios for 2050 and 2080, simulations with a tropical glacier-climate model indicate that glaciers will continue to retreat. According to the national Peruvian glacier inventories 43% of glacier area has disappeared between 1970 and 2003-2010 in the 19 snowy mountain ranges and a total of 8 355 new lakes have formed in deglaciating terrain. With glacier retreat new lakes form in parts of the glacier tongue where there is an overdeepening, and these lakes can be a source of natural hazards to downstrean populations. Therefore, the identification of possible future lakes is important to plan for preventive measures concerning possible lake outbursts as well as to understand changes in freshwater storage in the corresponding source areas. Modeling of glacier-bed overdeepenings and possible future lakes forming in such topographic depressions when becoming ice-free was done using the SRTM DEM from the year 2000 with a 90 m resolution and the 2003-2010 glacier outlines from the recently published national glacier inventory of Perú. The GIS-based analysis followed three main steps: (1) identification of flat glacier areas with less than 10° surface slope as a first-order spatial approximation to possible occurrences of glacier-bed overdeepenings; (2) application, using Google Earth, of three morphological indications of glacier-bed overdeepenings following Frey et al. (2010): steepening surface slope, onset of crevasse formation, lateral flow-narrowing; and (3) verification of the results from steps (1) and (2) by comparison with GlabTop modeling of bed topographies following Linsbauer et al. (2012) using the SRTM DEM, contour lines and constructed branch lines for all glaciers. A pilot study has already been carried out for the Cordillera Blanca. The results show that 31 major new lakes may form in the future. The total

  5. [Carotenogenesis of five strains of the algae Dunaliella sp. (Chlorophyceae) isolated from Venezuelan hypersaline lagoons].

    PubMed

    Guevara, Miguel; Lodeiros, César; Gómez, Olga; Lemus, Nathalie; Núñez, Paulino; Romero, Lolymar; Vásquez, Aléikar; Rosales, Néstor

    2005-01-01

    We evaluated discontinuous cultures (Algal medium at 0.5 mM of NaNO3, and 27% NaCI) of five strains of Dunaliella sp. isolated from Venezuelan hypersaline lagoons (Araya, Coche, Peonia, Cumaraguas. and Boca Chica) and one strain from a reference collection (Dunaliella salina, LB1644). Cultures were maintained to 25+/-1 degrees C, with constant aeration, photoperiod 12:12, and two light intensities (195 and 390 microE.m(-2).s(-1)) during 30 days. Cell count was recorded on a daily basis using a Neubaüer camera. Totals of chlorophyll a and carotenoids were measured at the end of the experiment. The largest cellular densities were measured during the smallest light intensities. The strain with the largest cellular density was isolated from Boca Chica (8 xl0(6) and 2.5 xl0(6) cel.ml(-1) a 390 and 195microE.m(-2).s(-1), respectively). The increment of light intensity produced a significant reduction of growth rates in all strains. Totals of carotenoids by volume were as large as 390 microE.m(-2).s(-1). Strains LB 1644, from Coche and Araya were those that produced the largest amount of carotenoids (38.4; 32.8 and 21.0 microg.ml(-1), respectively). Differences total carotenoids by cell between treatments were significant. The largest concentration was 390 microE.m(-2).s(-1). The strains LB 1644 and Coche produced the highest values of carotenes (137.14 and 106.06 pg.cel(-1), respectively). Differences in the relation carotenoid:chlorophyll a between the strains at various light intensities was significant. Strains LB1644 presented the largest value of the relation carotenoids:chlorophyll a (20:1) at 195 microE.m(-2).s(-1). No significant differences were detected in the strain Coche (15:1). All the other strains showed relations lower than one. Our results suggest that the strains of Coche and Araya show potential to be used in the biotechnology of carotenoids production.

  6. First results of a high resolution reflection seismic survey of the Central Northern Venezuelan Shelf

    NASA Astrophysics Data System (ADS)

    Avila, J.; van Welden, A.; Audemard, F.; de Batist, M.; Beck, C.; Scientific Party, G.

    2008-05-01

    . The main SSF fault is not clearly expressed in all profiles as a clear rupture of the sea floor sediments but rather as highly deformed zones. Our data set, also evidences preliminary, due to relatively wide spacing fo the seismic grid- the interest of the studied areas for the investigation of regional natural hazards (climatic, seismo-tectonic), and of the impact of sea level changes in the southeastern Caribbean. This project was funded by FONACIT project PI-2003000090 and French-Venezuelan ECOS-Nord scientific exchange program.

  7. Reply to the Comment on "Sandstone caves on Venezuelan tepuis: Return to pseudokarst?"

    NASA Astrophysics Data System (ADS)

    Aubrecht, R.; Lánczos, T.; Gregor, M.; Schlögl, J.; Šmída, B.; Liščák, P.; Brewer-Carías, Ch.; Vlček, L.

    2013-09-01

    In Aubrecht et al. (2011) we brought new data showing that the arenitic caves in the Venezuelan tepuis did not necessarily originate through quartz cement dissolution ('arenization') but the main portion of the caves originated because of poor lithification prior to erosion. An additional important process is lateritization which is responsible for at least 30% of the caves' volume. Sauro et al. (2012) in their comment support the 'arenization' theory (quartz cement dissolution) and provide several arguments against some points of our research. Their main objections and arguments relate to the following topics: 1) the validity of the arenization theory, 2) the origin and importance of the 'finger-flow' pillars, 3) the importance of the Schmidt hammer measurements and, 4) metamorphism of the Matauí Formation. In our reply we present further documentation that: The quartz cement dissolution theory of cave evolution was far less documented petrographically than the new theory presented by us. Although the presence of quartz dissolution is evident, there is no current evidence that it is widespread or that it plays a trigger role. Many of the presented examples of corrosion on quartz grains could have been caused by local alkalization. In addition, the hydrogeochemical data presented in the comment to support the 'arenization' theory do not in fact contradict our speleogenetic interpretations. 'Finger-flow' pillars are speleogenetic indicators and not speleogenetic factors. Their absence in some caves provides no evidence against our theory. Schmidt hammer measurements only objectivize the data on contrasting hardness in the Matauí Formation beds. They do not say anything about the origin of this difference. The arguments of Sauro et al. (2012) involve the metamorphic overprint of the Matauí Formation shown by the presence of pyrophyllite and quartz mobilizations. Because quartz mobilization also occurs in hypergenic conditions, it may be neglected as a metamorphic

  8. Hemostatic properties of Venezuelan Bothrops snake venoms with special reference to Bothrops isabelae venom.

    PubMed

    Rodríguez-Acosta, Alexis; Sánchez, Elda E; Márquez, Adriana; Carvajal, Zoila; Salazar, Ana M; Girón, María E; Estrella, Amalid; Gil, Amparo; Guerrero, Belsy

    2010-11-01

    In Venezuela, Bothrops snakes are responsible for more than 80% of all recorded snakebites. This study focuses on the biological and hemostatic characteristics of Bothrops isabelae venom along with its comparative characteristics with two other closely related Bothrops venoms, Bothrops atrox and Bothrops colombiensis. Electrophoretic profiles of crude B. isabelae venom showed protein bands between 14 and 100 kDa with the majority in the range of 14-31 kDa. The molecular exclusion chromatographic profile of this venom contains five fractions (F1-F5). Amidolytic activity evaluation evidenced strong thrombin-like followed by kallikrein-like activities in crude venom and in fractions F1 and F2. The fibrinogenolytic activity of B. isabelae venom at a ratio of 100:1 (fibrinogen/venom) induced a degradation of A alpha and B beta chains at 15 min and 2 h, respectively. At a ratio of 100:10, a total degradation of A alpha and B beta chains at 5 min and of gamma chains at 24 h was apparent. This current study evidences one of rarely reported for Bothrops venoms, which resembles the physiologic effect of plasmin. B. isabelae venom as well as F2 and F3 fractions, contain fibrinolytic activity on fibrin plate of 36, 23.5 and 9.45 mm(2)/microg, respectively using 25 microg of protein. Crude venom and F1 fraction showed gelatinolytic activity. Comparative analysis amongst Venezuelan bothropoid venoms, evidenced that the LD(50) of B. isabelae (5.9 mg/kg) was similar to B. atrox-Puerto Ayacucho 1 (6.1 mg/kg) and B. colombiensis-Caucagua (5.8 mg/kg). B. isabelae venom showed minor hemorrhagic activity, whereas B. atrox-Parguasa (Bolivar state) was the most hemorrhagic. In this study, a relative high thrombin-like activity was observed in B. colombiensis venoms (502-568 mUA/min/mg), and a relative high factor Xa-like activity was found in B. atrox venoms (126-294 mUA/min/mg). Fibrinolytic activity evaluated with 10 microg protein, showed that B. isabelae venom contained higher

  9. Characterization of enzootic foci of Venezuelan equine encephalitis virus in western Venezuela.

    PubMed

    Barrera, R; Torres, N; Freier, J E; Navarro, J C; García, C Z; Salas, R; Vasquez, C; Weaver, S C

    2001-01-01

    The distribution of the sylvatic subtype ID Venezuelan equine encephalitis (VEE) viruses in the lowland tropical forests of western Venezuela was investigated using remote sensing and geographic information system technologies. Landsat 5 Thematic Mapper satellite imagery was used to study the reflectance patterns of VEE endemic foci and to identify other locations with similar reflectance patterns. Enzootic VEE virus variants isolated during this study are the closest genetic relatives of the epizootic viruses that emerged in western Venezuela during 1992-1993. VEE virus surveillance was conducted by exposing sentinel hamsters to mosquito bites and trapping wild vertebrates in seven forests identified and located by means of the satellite image. We isolated VEE viruses from 48 of a total of 1,363 sentinel hamsters in two of the forests on six occasions, in both dry and wet seasons. None of the 12 small vertebrates captured in 8,190 trap-nights showed signs of previous VEE virus infection. The satellite image was classified into 13 validated classes of land use/vegetation using unsupervised and supervised techniques. Data derived from the image consisted of the raw digital values of near- and mid-infrared bands 4, 5, and 7, derived Tasseled Cap indices of wetness, greenness, and brightness, and the Normalized Difference Vegetation Index. Digitized maps provided ancillary data of elevation and soil geomorphology. Image enhancement was applied using Principal Component Analysis. A digital layer of roads together with georeferenced images was used to locate the study sites. A cluster analysis using the above data revealed two main groups of dense forests separated by spectral properties, altitude, and soil geomorphology. Virus was isolated more frequently from the forest type identified on flat flood plains of main rivers rather than the forest type found on the rolling hills of the study area. The spatial analysis suggests that mosquitoes carrying the enzootic viruses

  10. Kinetic, Mutational, and Structural Studies of the Venezuelan Equine Encephalitis Virus Nonstructural Protein 2 Cysteine Protease

    PubMed Central

    Hu, Xin; Compton, Jaimee R.; Leary, Dagmar H.; Olson, Mark A.; Lee, Michael S.; Cheung, Jonah; Ye, Wenjuan; Ferrer, Mark; Southall, Noel; Jadhav, Ajit; Glass, Pamela J.; Marugan, Juan; Legler, Patricia M.

    2017-01-01

    The Venezuelan equine encephalitis virus (VEEV) nonstructural protein 2 (nsP2) cysteine protease (EC 3.4.22.-) is essential for viral replication and is involved in the cytopathic effects (CPE) of the virus. The VEEV nsP2 protease is a member of MEROPS Clan CN and characteristically contains a papain-like protease linked to an S-adenosyl-L-methionine dependent RNA methyltransferase (SAM MTase) domain. The protease contains an alternative active site motif, 475NVCWAK480, which differs from papain’s (CGS25CWAFS), and the enzyme lacks a transition state (TS) stabilizing residue homologous to Q19 in papain. To understand the roles of conserved residues in catalysis we determined the structure of the free enzyme, and the first structure of an inhibitor-bound alphaviral protease. The peptide-like E64d inhibitor was found to bind beneath a β-hairpin at the interface of the SAM MTase and protease domains. His-546 adopted a conformation that differed from that found in the free enzyme, each conformer may assist in leaving group departure of either the amine or Cys thiolate during the catalytic cycle. Interestingly, E64c (200 μM), the carboxylic acid form of the E64d ester, did not inhibit the nsP2 protease. To identify key residues involved in substrate binding, a number of mutants were analyzed. Mutation of the motif residue, N475A, led to a 24-fold reduction in kcat/Km, and the conformation of this residue did not change after inhibition. N475 forms a hydrogen bond with R662 in the SAM MTase domain, and the R662A and R662K mutations both led to 16-fold reductions in kcat/Km. N475 forms the base of the P1 binding site and likely orients the substrate for nucleophilic attack or plays a role in product release. An Asn homologous to N475 is similarly found in coronaviral papain-like proteases (PLpro) of the Severe Acute Respiratory Syndrome (SARS) virus and Middle Eastern Respiratory virus (MERS). Mutation of another motif residue, K480A, led to a 9-fold decrease in kcat

  11. Evolution of Irruputuncu volcano, Central Andes, northern Chile

    NASA Astrophysics Data System (ADS)

    Rodríguez, I.; Roche, O.; Moune, S.; Aguilera, F.; Campos, E.; Pizarro, M.

    2015-11-01

    The Irruputuncu is an active volcano located in northern Chile within the Central Andean Volcanic Zone (CAVZ) and that has produced andesitic to trachy-andesitic magmas over the last ˜258 ± 49 ka. We report petrographical and geochemical data, new geochronological ages and for the first time a detailed geological map representing the eruptive products generated by the Irruputuncu volcano. The detailed study on the volcanic products allows us to establish a temporal evolution of the edifice. We propose that the Irruputuncu volcanic history can be divided in two stages, both dominated by effusive activity: Irruputuncu I and II. The oldest identified products that mark the beginning of Irruputuncu I are small-volume pyroclastic flow deposits generated during an explosive phase that may have been triggered by magma injection as suggested by mingling features in the clasts. This event was followed by generation of large lava flows and the edifice grew until destabilization of its SW flank through the generation of a debris avalanche, which ended Irruputuncu I. New effusive activity generated lavas flows to the NW at the beginning of Irruputuncu II. In the meantime, lava domes that grew in the summit were destabilized, as shown by two well-preserved block-and-ash flow deposits. The first phase of dome collapse, in particular, generated highly mobile pyroclastic flows that propagated up to ˜8 km from their source on gentle slopes as low as 11° in distal areas. The actual activity is characterized by deposition of sulfur and permanent gas emissions, producing a gas plume that reaches 200 m above the crater. The maximum volume of this volcanic system is of ˜4 km3, being one of the smallest active volcano of Central Andes.

  12. High resolution precipitation climatology for the Andes of South Ecuador

    NASA Astrophysics Data System (ADS)

    Trachte, Katja; Bendix, Jörg

    2014-05-01

    The climate of Ecuador is strongly dominated by the complex structure of the Andes Mountains. Due to their heights and north-south orientation they act like a barrier, which cause delineation between the western and eastern flanks, as well as the inner-Andean areas. Commonly the Ecuadorian climate is classified in three zones, Costa, Interandina and Oriente. Existing precipitation products such as the GPCC or TRMM data are enabled to represent these climate zones, but because of their spatial resolution, they pass to capture the different regimes within a zone. Especially the inner-Andean region (Interandina) with its characteristic complex terrain shows spatially high climate variability. Local circulation systems, e.g. mountain-valley breezes as well as effects of windward and lee-side, drive the climate conditions allowing for the differentiation of air temperature and rainfall distribution on relative small scales. These highly variable patterns are also reflected by the diversity of ecosystems, e.g. rainforest, dry forest and Paramo, in a relative small area. In order to represent the local systems a dynamical downscaling approach for the Ecuadorian region is applied. In doing so the Weather Research and Forecasting (WRF) model is used. A suitable model setup was evaluated within a sensitivity study, where various parametrization schemes were tested. The most suitable physics combination was used for a 30 year hint cast simulation. The poster presents first results of the high resolution climate simulations. On the basis of the spatial distribution of rainfall patterns distinct precipitation regimes within the Interandina will be shown. The aim is to highlight and discuss the importance of the adequately representation of the terrain in mountainous regions like the Andean Mountains.

  13. Erosion by Ice and Water in the Southern Andes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This scene on the remote, rugged Argentine/Chilean border in the far southern Andes Mountains offers numerous, dramatic examples of both erosional processes and features of ice and water. The sharp, glaciated crest of the Cerro San Lorenzo (center) exceeds 12,000 feet and casts a long shadow southeastward. Glaciers on its western flank flow into the valley. This Electronic Still Camera photo was taken from the International Space Station, in December 2000 (late spring) when most of the previous winter's snow had melted below an altitude of 6,000 feet. Lago Pueyrredon, and the other lakes visible here, have been excavated by geologically recent episodes of glacier erosion, when glaciers extended all the way onto the lowland plains (top right). Since the last melting of the glaciers (15,000 years ago) three distinct fan deltas (semicircular features, marked with arrows) have formed where rivers flow into the lake. Counterclockwise currents in the lake-driven by strong winds from the west-have generated thin sand spits from each fan-delta. The largest spit (attached to the largest fan-delta, see right arrow) has isolated an approximately 10-kilometer long segment of the south end of the lake. The river that constructed the largest fan presently discharges turbid water to this isolated basin, giving it a lighter color than the rest of the lake. Glacial data collected over the past 50 years indicate that small ice bodies are disappearing at accelerated rates. (EOS, vol 81, no. 24, June 13, 2000) Predictions are that large fluctuations in land ice, with significant implications to society, are possible in the coming decades and centuries due to natural and anthropogenic climate change. Before glacial data can be used to address critical problems pertaining to the world's economic and environmental health, more detailed information about such glaciers is needed. Image ISS001-ESC-5113 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  14. The Little Ice Age in the tropical Andes

    NASA Astrophysics Data System (ADS)

    Jomelli, V.; Cooley, D.; Naveau, P.; Rabatel, A.

    2003-12-01

    The period known as the Little Ice Age, from the 17th to the 19th century, brought a cooling of around 0.5 degrees Celsius as well as varyingly humid episodes Eurasia and North America. Because of a lack of long paleoclimatic time series in the tropical Andes, it is still unclear if similar cooling occurred over these tropical and Southern Hemisphere regions. Furthermore, if changes did take place, it is currently not well established if they were temporally synchronous or shifted with respect of the variations in the Northern Hemisphere or the globe. To look into this important climatic question and for advancing our understanding of the past climate links between the tropics and higher latitudes, 25 glaciers located in Bolivia and in Peru were carefully selected. Glacial activity and environmental changes were analyzed using lichenometry. Largest lichen diameters were measured in the different glacial basins. To better analyze these maximum diameters and to more appropriately represent uncertainty and the character of this collected data, age estimates of the different moraine systems were derived using extreme value theory rather than the traditional averaging. The results reveal two particular phases of glacier growth, 1550-1600 and 1800-1850. These two phases have also been identified in other proxy records, such as ice-cores and documentary data (particularly from church chronicles). In order to understand the climatic changes that could have contributed to the glacial variations, a simple model based on both precipitations and temperatures is applied to estimate mass balance questions in the basins. A cooling of the order of 0.5 C seems to be the most consistent with the data. Finally, these findings are compared with the better-known histories of Northern Hemisphere mid-latitude glaciers.

  15. The nature of orogenic crust in the central Andes

    NASA Astrophysics Data System (ADS)

    Beck, Susan L.; Zandt, George

    2002-10-01

    The central Andes (16°-22°S) are part of an active continental margin mountain belt and the result of shortening of the weak western edge of South America between the strong lithospheres of the subducting Nazca plate and the underthrusting Brazilian shield. We have combined receiver function and surface wave dispersion results from the BANJO-SEDA project with other geophysical studies to characterize the nature of the continental crust and mantle lithospheric structure. The major results are as follows: (1) The crust supporting the high elevations is thick and has a felsic to intermediate bulk composition. (2) The relatively strong Brazilian lithosphere is underthrusting as far west (65.5°W) as the high elevations of the western part of the Eastern Cordillera (EC) but does not underthrust the entire Altiplano. (3) The subcrustal lithosphere is delaminating piecemeal under the Altiplano-EC boundary but is not completely removed beneath the central Altiplano. The Altiplano crust is characterized by a brittle upper crust decoupled from a very weak lower crust that is dominated by ductile deformation, leading to lower crustal flow and flat topography. In contrast, in the high-relief, inland-sloping regions of the EC and sub-Andean zone, the upper crust is still strongly coupled across the basal thrust of the fold-thrust belt to the underthrusting Brazilian Shield lithosphere. Subcrustal shortening between the Altiplano and Brazilian lithosphere appears to be accommodated by delamination near the Altiplano-EC boundary. Our study suggests that orogenic reworking may be an important part of the "felsification" of continental crust.

  16. Glacier loss and emerging hydrologic vulnerabilities in the Peruvian Andes

    NASA Astrophysics Data System (ADS)

    Mark, B. G.; McKenzie, J. M.; Baraer, M.; Lagos, P.; Lautz, L.; Carey, M.; Bury, J.; Crumley, R.; Wigmore, O.; Somers, L. D.

    2015-12-01

    Accelerating glacier recession in the tropical Andes is transforming downstream hydrology, while increasing demands for water by end-users (even beyond the watershed limits) is complicating the assessment of vulnerability. Future scenarios of hydro-climatic vulnerability require a better understanding of coupled hydrologic and human systems, involving both multiscale process studies and more robust models of glacier-climate interactions. We synthesize research in two proglacial valleys of glacierized mountain ranges in different regions of Peru that are both in proximity to growing water usage from urban sectors, agriculture, hydroelectric generation, and mining. In both the Santa River watershed draining the Cordillera Blanca and the Shullcas River watershed below Hyuatapallana Mountain in Junin, glaciers have receded over 25% since the 1980s. Historical runoff and glacier data, combined with glacier-climate modeling, show a long-term decrease in discharge resulting from a net loss of stored water. We find evidence that this altered hydrology is transforming proglacial wetland ecology and water quality, even while water resource use has intensified. Beyond glaciers, our results show that over 60% of the dry season base flow in each watershed is groundwater sourced from heterogeneous aquifers. Municipal water supply in Huancayo already relies on 18 groundwater wells. Perceptions of water availability and actual water use practices remain relatively divorced from the actual water resources provided from each mountain range. Critical changes in glacier volume and water supply are not perceived or acknowledged consistently amongst different water users, nor reflected in water management decisions. In order to identify, understand, model, and adapt to climate-glacier-water changes, it is vital to integrate the analysis of water availability and groundwater processes (the domain of hydrologists) with that of water use (the focus for social scientists). Attention must be

  17. Glaciological studies in the central Andes using AIRSAR/TOPSAR

    NASA Technical Reports Server (NTRS)

    Forster, Richard R.; Klein, Andrew G.; Blodgett, Troy A.; Isacks, Bryan L.

    1993-01-01

    The interaction of climate and topography in mountainous regions is dramatically expressed in the spatial distribution of glaciers and snowcover. Monitoring existing alpine glaciers and snow extent provides insight into the present mountain climate system and how it is changing, while mapping the positions of former glaciers as recorded in landforms such as cirques and moraines provide a record of the large past climate change associated with the last glacial maximum. The Andes are an ideal mountain range in which to study the response of snow and ice to past and present climate change. Their expansive latitudinal extent offers the opportunity to study glaciers in diverse climate settings from the tropical glaciers of Peru and Bolivia to the ice caps and tide-water glaciers of sub-polar Patagonia. SAR has advantages over traditional passive remote sensing instruments for monitoring present snow and ice and differentiating moraine relative ages. The cloud penetrating ability of SAR is indispensable for perennially cloud covered mountains. Snow and ice facies can be distinguished from SAR's response to surface roughness, liquid water content and grain size distribution. The combination of SAR with a coregestered high-resolution DEM (TOPSAR) provides a promising tool for measuring glacier change in three dimensions, thus allowing ice volume change to be measured directly. The change in moraine surface roughness over time enables SAR to differentiate older from younger moraines. Polarimetric SAR data have been used to distinguish snow and ice facies and relatively date moraines. However, both algorithms are still experimental and require ground truth verification. We plan to extend the SAR classification of snow and ice facies and moraine age beyond the ground truth sites to throughout the Cordillera Real to provide a regional view of past and present snow and ice. The high resolution DEM will enhance the SAR moraine dating technique by discriminating relative ages

  18. Bayesian spatiotemporal interpolation of rainfall in the Central Chilean Andes

    NASA Astrophysics Data System (ADS)

    Ossa-Moreno, Juan; Keir, Greg; McIntyre, Neil

    2016-04-01

    Water availability in the populous and economically significant Central Chilean region is governed by complex interactions between precipitation, temperature, snow and glacier melt, and streamflow. Streamflow prediction at daily time scales depends strongly on accurate estimations of precipitation in this predominantly dry region, particularly during the winter period. This can be difficult as gauged rainfall records are scarce, especially in the higher elevation regions of the Chilean Andes, and topographic influences on rainfall are not well understood. Remotely sensed precipitation and topographic products can be used to construct spatiotemporal multivariate regression models to estimate rainfall at ungauged locations. However, classical estimation methods such as kriging cannot easily accommodate the complicated statistical features of the data, including many 'no rainfall' observations, as well as non-normality, non-stationarity, and temporal autocorrelation. We use a separable space-time model to predict rainfall using the R-INLA package for computationally efficient Bayesian inference, using the gridded CHIRPS satellite-based rainfall dataset and digital elevation models as covariates. We jointly model both the probability of rainfall occurrence on a given day (using a binomial likelihood) as well as amount (using a gamma likelihood or similar). Correlation in space and time is modelled using a Gaussian Markov Random Field (GMRF) with a Matérn spatial covariance function which can evolve over time according to an autoregressive model if desired. It is possible to evaluate the GMRF at relatively coarse temporal resolution to speed up computations, but still produce daily rainfall predictions. We describe the process of model selection and inference using an information criterion approach, which we use to objectively select from competing models with various combinations of temporal smoothing, likelihoods, and autoregressive model orders.

  19. Two New Species of Black Flies (Diptera: Simuliidae) from the High Andes of Colombia.

    PubMed

    Mantilla, Juan S; Moncada, Ligia I; Matta, Nubia E; Adler, Peter H

    2013-01-01

    The females, males, pupae, and larvae of two new species of Simulium are described and illustrated from a small stream 3950 m above sea level in the Lake Otún area of the Colombian Andes Mountains. Simulium (Pternaspatha) quimbayium n. sp. represents a 630-km northeastern extension of the distributional range of previously known members of the subgenus Pternaspatha, and Simulium (Psilopelmia) machetorum n. sp. represents the highest altitude recorded for a species of the subgenus Psilopelmia. These species illustrate the unique simuliid biodiversity in the páramo ecosystem of the high northern Andes.

  20. Phytoplankton in the northwestern Kara Sea

    NASA Astrophysics Data System (ADS)

    Sukhanova, I. N.; Flint, M. V.; Druzhkova, E. I.; Sazhin, A. F.; Sergeeva, V. M.

    2015-07-01

    Studies were conducted in the northwestern Kara Sea in late September of 2007 and 2011. The assessment of species, size, structure, abundance, and biomass of phytoplankton and the role of autotrophic and heterotrophic components in phytocenoses was conducted. The abundance of autotrophic micro-, nanoand picoplankton increased by more than an order of magnitude in each of the following smaller-sized groups of algae. Microphytoplankton dominated in the total biomass of autotrophic phytoplankton. The wet biomass of microphytoplankton was 2.5 times higher than the wet biomass of nanophytoplankton and 5 times higher than that of picoplankton. Nanophytoplankton dominated in abundance and biomass in the heterotrophic component of phytoplankton. The ratio of the total abundance of autotrophic and heterotrophic phytotoplankton was 7: 1, the ratio of the wet biomass of the both groups was 2.5: 1, and the proportion of the carbon biomass was 2: 1. Three biotopes were distinguished in the area of the outer shelf, the continental slope, and the deepwater area adjacent to the St. Anna Trough, which differed in composition and quantitative characteristics of phytocenoses. Frontal zones dividing the biotopes are characterized by high phytoplankton biomass and the dominance of diatoms in the community (more than 40% of the total biomass), which indicates the local availability of "new" nutrients for planktonic algae.

  1. MISR Images Wildfires in Northwestern US

    NASA Technical Reports Server (NTRS)

    2000-01-01

    MISR image of smoke plumes from devastating wildfires in the northwestern US. This view of the Clearwater and Salmon River Mountains in Idaho was acquired on August 5, 2000 (Terra orbit 3370). The body of water to the left of image center is the Cascade Reservoir, located about 100 km north of Boise and 80 km east of the Snake River. North is at the top, and the image is approximately 380 km across.

    In addition to the huge plumes traversing the mountains in the northern part of the image, smoke accumulating in the lower elevation canyons and plains is visible. This image was generated using data from the MISR camera that looks forward at a steep angle (70.5 degrees). The smoke is far more visible when viewed at this highly oblique angle than it would be in a conventional, straight-downward view. In creating this color composite, data from the blue and green MISR bands, acquired at 1.1-km spatial resolution, were digitally 'sharpened' using 275-m resolution data acquired in the red band.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

    For more information: http://www-misr.jpl.nasa.gov

  2. Northwestern Tharsis Latent Outflow Activity Mars

    NASA Technical Reports Server (NTRS)

    Dohm, J. M.; Anderson, R. C.; Baker, V. R.; Ferris, J. C.; Hare, T. M.; Strom, R. G.; Rudd, L.; Rice, J. W., Jr.; Scott, D. H.

    2000-01-01

    Previously defined outflow channels, which are indicated by relict landforms similar to those observed on Earth, signify ancient catastrophic flood events on Mars. These conspicuous geomorphic features are some of the most remarkable yet profound discoveries made by geologists to date. These outflow channels, which debouched tremendous volumes of water into topographic lows such as Chryse, Utopia, Elysium, and Hellas Planitiae, may represent the beginning of warmer and wetter climatic periods unlike the present-day cold and dry Mars. In addition to the previously identified outflow channels, observations permitted by the newly acquired Mars Orbiter Laser Altimeter (MOLA) data have revealed a system of gigantic valleys, referred to as the northwestern slope valleys (NSV), that are located to the northwest of a huge shield volcano, Arsia Mons, western hemisphere of Mars. These features generally correspond spatially to gravity lows similar to the easternmost, circum-Chryse outflow channel systems. Geologic investigations of the Tharsis region suggest that the large valley system pre-dates the construction of Arsia Mons and its extensive associated lava flows of mainly Late Hesperian and Amazonian age and coincides stratigraphically with the early development of the circum-Chryse outflow channel systems that debouch into Chryse Planitia. This newly identified system, the NSV, potentially signifies the largest flood event(s) ever recorded for the solar system. Additional information is contained in original extended abstract.

  3. Kinematic history of the retroarc thrust belt in the central Andes of Argentina at 24-25°S: significant Andean shortening and sporadic foreland-ward deformation propagation

    NASA Astrophysics Data System (ADS)

    Pearson, D. M.; Kapp, P. A.; Decelles, P. G.; Reiners, P. W.

    2009-12-01

    The southward along-strike transition from major thin-skinned shortening of Bolivia to the significantly lower magnitude of thick-skinned shortening in northwestern Argentina has often been attributed to the presence of a thick mid to late Paleozoic section in Bolivia relative to a thin group of correlative rocks in northwestern Argentina that were affected by significant Cretaceous rifting. Despite the Andes being regarded as an archetype of ocean-continent convergence, the northwestern Argentine Andes have remained enigmatic in a structural and tectonic context. This study integrates regional geological mapping, structural analysis, and geo- and thermochronology from the Salta province of northwestern Argentina. Geological mapping in the Cachi range at ~25° S latitude revealed the presence of an ~60° west-dipping package of rocks, passing from low grade phyllites in the eastern part of the range into cordierite-bearing, anatectic and arc-related rocks in the core of the range (one anatectic pluton yielded a U/Pb zircon age of 488 ± 10 Ma). Detrital zircons record U-Pb ages demonstrating that the highest-grade, structurally highest rocks are the oldest (maximum depositional age (MDA) ~548 Ma), rocks at structurally lower levels are younger (MDA ~538 Ma), whereas the structurally lowest rocks are the youngest (MDA ~523 Ma). Double dating some of these same zircons using the low temperature U-Th/He system indicates that at least 6-8 km of Miocene (15.7 ± 0.4 Ma) exhumation occurred in the core of the range at this time, yet exhumation at the eastern range margin was insufficient to reset zircons. U/Pb zircon ages from a tuff within growth strata in the footwall of a major thrust fault ~50 km east of Cachi demonstrate that shortening was ongoing there at 9.4 ± 0.4 Ma, yielding a propagation rate of the thrust belt of ~8 km/Ma. Since ~9 Ma, deformation has jumped ~150 km eastward to the Santa Barbara ranges, yielding an average rate of >30 km/Ma. Many thrust

  4. Evaluation of neurovirulence and biodistribution of Venezuelan equine encephalitis replicon particles expressing herpes simplex virus type 2 glycoprotein D.

    PubMed

    Kowalski, Jacek; Adkins, Karissa; Gangolli, Seema; Ren, Jian; Arendt, Heather; DeStefano, Joanne; Obregon, Jennifer; Tummolo, Donna; Natuk, Robert J; Brown, Tom P; Parks, Christopher L; Udem, Stephen A; Long, Deborah

    2007-03-08

    The safety of a propagation-defective Venezuelan equine encephalitis virus (VEEV) replicon particle vaccine was examined in mice. After intracranial inoculation we observed approximately 5% body weight loss, modest inflammatory changes in the brain, genome replication, and foreign gene expression. These changes were transient and significantly less severe than those caused by TC-83, a live-attenuated vaccinal strain of VEEV that has been safely used to immunize military personnel and laboratory workers. Replicon particles injected intramuscularly or intravenously were detected at limited sites 3 days post-administration, and were undetectable by day 22. There was no evidence of dissemination to spinal cord or brain after systemic administration. These results demonstrate that propagation-defective VEEV replicon particles are minimally neurovirulent and lack neuroinvasive potential.

  5. INDUCTION OF NEUTRALIZING ANTIBODIES TO HENDRA AND NIPAH GLYCOPROTEINS USING A VENEZUELAN EQUINE ENCEPHALITIS VIRUS IN VIVO EXPESSION SYSTEM

    PubMed Central

    Defang, Gabriel N.; Khetawat, Dimple; Broder, Christopher C.; Quinnan, Gerald V.

    2010-01-01

    The emergence of Hendra Virus (HeV) and Nipah Virus (NiV) which can cause fatal infections in both animals and humans has triggered a search for an effective vaccine. Here, we have explored the potential for generating an effective humoral immune response to these zoonotic pathogens using an alphavirus-based vaccine platform. Groups of mice were immunized with Venezuelan equine encephalitis virus replicon particles (VRP) encoding the attachment or fusion glycoproteins of either HeV or NiV. We demonstrate the induction of highly potent cross-reactive neutralizing antibodies to both viruses using this approach. Preliminary study suggested early enhancement in the antibody response with use of a modified version of VRP. Overall, these data suggest that the use of an alphavirus-derived vaccine platform might serve as a viable approach for development of an effective vaccine against the henipaviruses. PMID:21050901

  6. Equine Amplification and Virulence of Subtype IE Venezuelan Equine Encephalitis Viruses Isolated during the 1993 and 1996 Mexican Epizootics

    PubMed Central

    Gonzalez, Dante; Estrada-Franco, José G.; Carrara, Anne-Sophie; Aronson, Judith F.

    2003-01-01

    To assess the role of horses as amplification hosts during the 1993 and 1996 Mexican Venezuelan equine encephalitis (VEE) epizootics, we subcutaneously infected 10 horses by using four different equine isolates. Most horses showed little or no disease and low or nonexistent viremia. Neurologic disease developed in only 1 horse, and brain histopathologic examination showed meningeal lymphocytic infiltration, perivascular cuffing, and focalencephalitis. Three animals showed mild meningoencephalitis without clinical disease. Viral RNA was detected in the brain of several animals 12-14 days after infection. These data suggest that the duration and scope of the recent Mexican epizootics were limited by lack of equine amplification characteristic of previous, more extensive VEE outbreaks. The Mexican epizootics may have resulted from the circulation of a more equine-neurotropic, subtype IE virus strain or from increased transmission to horses due to amplification by other vertebrate hosts or transmission by more competent mosquito vectors. PMID:12603985

  7. Cataract and pterygium surgery results in Venezuelan patients treated in the Misión Milagro program.

    PubMed

    Triana, Idalia; Socarrás, Oaris Angeles de Los; Rondón, Nelsis

    2012-07-01

    An intervention to address vision loss was carried out in 2008 in Táchira, Venezuela, by health teams of the joint Cuban-Venezuelan initiative known as Misión Milagro. It included active case identification of patients with ophthalmologic conditions and, where warranted, surgery, followup, rehabilitation and medical discharge. From a universe of 345 patients aged ≥18 years with ophthalmologic conditions found, 210 were selected for cataract or pterygium surgery. Of cataract patients, 55.2% recovered optimal vision within three months after surgery, as did 90.9% of those with pterygium; frequency of complications was 15.4% in cataract patients and 41.7% in pterygium patients. The intervention was considered successful, although many patients' low-income status required premature postoperative return to their jobs and other labors, a factor considered detrimental to optimal recovery.

  8. Jurassic platform development, northwestern Gulf of Mexico

    SciTech Connect

    Moore, C.H. Jr.

    1987-05-01

    Triassic and Early Jurassic rifting set the stage for the subsequent development of carbonate platforms in the Late Jurassic. These platforms formed along the interior margins of salt basins separated from the main ancestral Gulf of Mexico by a series of positive features. A major sea level rise, after deposition of the Louann Salt (late Callovian), drowned the interior salt basins around the margins of the Gulf of Mexico, leading to an anoxic event. Organic-rich sediments of the lower Smackover were deposited as a basin-fill sequence, forming one of the major hydrocarbon source rocks of the region. As sea level rise slowed in the late Oxfordian, carbonate production began to catch up with sea level rise along the basin margins, leading to the initial development of a rimmed carbonate platform. The platform margin was marked by high-energy ooid grainstones, while crustacean pellet muds were deposited in the platform interior. A high-energy ooid-dominated platform (upper Smackover) developed in the late Oxfordian when sea level reached a standstill. During the subsequent Kimmeridgian sea level rise, a second rimmed carbonate platform, the Haynesville, was developed. During the initial rise, grainstones were deposited on the platform margin, while the interior was dominated by evaporites (Buckner) and siliciclastics. As sea level slowed and reached a standstill, the platform margin facies extended shoreward (Gilmer) and a high-energy platform, analogous to the upper Smackover, was formed. The Smackover and Haynesville platforms of the northwestern gulf show a parallel evolution in response to cyclic changes in Upper Jurassic sea level.

  9. The atypical Caribbean-Colombia oceanic plateau and its role in the deformation of the Northern Andes

    NASA Astrophysics Data System (ADS)

    Ferrari, L.; Lopez-Martinez, M.; Petrone, C. M.; Serrano, L.

    2013-05-01

    The Late Cretaceous to Early Tertiary tectono-magmatic evolution of the Northern Andes has been strongly influenced by the dextral oblique interaction of the Caribbean-Colombian oceanic plateau (CCOP) with northwestern South America. This complex interaction has resulted in several pulses of transpressional deformation and crustal accretion to the South America plate but also in a widespread deformation in the plateau itself. In this peculiar type of orogeny one of the factors controlling the deformation is the crustal structure and thus the rheological profiles of the two lithospheric sections that interact. The genesis of the CCOP has been traditionally associated to the melting of the Galapagos plume head when it impacted the Farallon plate, which is supposed to have built an unsubductable and thick crustal section. This interpretation was based on the apparent clustering of ages at ~91-89 Ma for several obducted fragments of the CCOP in northwestern South America and in the Caribbean islands. However, seismic profiles show that magmatism added a very variable amount but no more than 10 km of igneous material to the original crust of the Farallon plate, making the CCOP much more irregular than other oceanic plateaus. Recent studies of key areas of the obducted part of the CCOP contradict the notion that the plateau formed by melting of a plume head at ~ 90 Ma. Particularly, new geochronologic data and petrologic modeling from the small Gorgona Island document a magmatic activity spanning the whole Late Cretaceous (98.7±7.7 to 64.4±5 Ma) and a progressive increase in the degree of melting and melt extraction with time. Multiple magmatic pulses over several tens of Ma in small areas like Gorgona, are also recognized in other areas of the CCOP, documenting a long period of igneous activity with peaks at 74-76, 80-82, and 88-90 Ma in decreasing order of importance. Even older, Early Cretaceous ages, have been reported for fragments in Costa Rica and Curaçao. A

  10. Evolution of crustal thickening in the central Andes, Bolivia

    NASA Astrophysics Data System (ADS)

    Eichelberger, Nathan; McQuarrie, Nadine; Ryan, Jamie; Karimi, Bobak; Beck, Susan; Zandt, George

    2015-09-01

    Paleoelevation histories from the central Andes in Bolivia have suggested that the geodynamic evolution of the region has been punctuated by periods of large-scale lithospheric removal that drive rapid increases in elevation at the surface. Here, we evaluate viable times and locations of material loss using a map-view reconstruction of the Bolivian orocline displacement field to forward-model predicted crustal thicknesses. Two volumetric models are presented that test assumed pre-deformation crustal thicknesses of 35 km and 40 km. Both models predict that modern crustal thicknesses were achieved first in the northern Eastern Cordillera (EC) by 30-20 Ma but remained below modern in the southern EC until ≤10 Ma. The Altiplano is predicted to have achieved modern crustal thickness after 10 Ma but only with a pre-deformation thickness of 50 km, including 10 km of sediment. At the final stage, the models predict 8-25% regional excess crustal volume compared to modern thickness, largely concentrated in the northern EC. The excess predicted volume from 20 to 0 Ma can be accounted for by: 1) crustal flow to the WC and/or Peru, 2) localized removal of the lower crust, or 3) a combination of the two. Only models with initial crustal thicknesses >35 km predict excess volumes sufficient to account for potential crustal thickness deficits in Peru and allow for lower crustal loss. However, both initial thickness models predict that modern crustal thicknesses were achieved over the same time periods that paleoelevation histories indicate the development of modern elevations. Localized removal of lower crust is only necessary in the northern EC where crustal thickness exceeds modern by 20 Ma, prior to paleoelevation estimates of modern elevations by 15 Ma. In the Altiplano, crustal thicknesses match modern values at 10 Ma and can only exceed modern values by 5 Ma, post-dating when modern elevations were thought to have been established. Collectively, these models predict that

  11. Motion of continental slivers and creeping subduction in the northern Andes

    NASA Astrophysics Data System (ADS)

    Nocquet, J.-M.; Villegas-Lanza, J. C.; Chlieh, M.; Mothes, P. A.; Rolandone, F.; Jarrin, P.; Cisneros, D.; Alvarado, A.; Audin, L.; Bondoux, F.; Martin, X.; Font, Y.; Régnier, M.; Vallée, M.; Tran, T.; Beauval, C.; Maguiña Mendoza, J. M.; Martinez, W.; Tavera, H.; Yepes, H.

    2014-04-01

    Along the western margin of South America, plate convergence is accommodated by slip on the subduction interface and deformation of the overriding continent. In Chile, Bolivia, Ecuador and Colombia, continental deformation occurs mostly through the motion of discrete domains, hundreds to thousands of kilometres in scale. These continental slivers are wedged between the Nazca and stable South American plates. Here we use geodetic data to identify another large continental sliver in Peru that is about 300-400 km wide and 1,500 km long, which we call the Inca Sliver. We show that movement of the slivers parallel to the subduction trench is controlled by the obliquity of plate convergence and is linked to prominent features of the Andes Mountains. For example, the Altiplano is located at the boundary of converging slivers at the concave bend of the central Andes, and the extending Gulf of Guayaquil is located at the boundary of diverging slivers at the convex bend of the northern Andes. Motion of a few large continental slivers therefore controls the present-day deformation of nearly the entire Andes mountain range. We also show that a 1,000-km-long section of the plate interface in northern Peru and southern Ecuador slips predominantly aseismically, a behaviour that contrasts with the highly seismic neighbouring segments. The primary characteristics of this low-coupled segment are shared by ~20% of the subduction zones in the eastern Pacific Rim.

  12. Lichenometric dating using Rhizocarpon subgenus Rhizocarpon in the Patagonian Andes, Argentina

    NASA Astrophysics Data System (ADS)

    Garibotti, Irene Adriana; Villalba, Ricardo

    2009-05-01

    This study represents the first attempt to develop and apply lichenometric dating curves of Rhizocarpon subgenus Rhizocarpon for dating glacier fluctuations in the Patagonian Andes. Six glaciers were studied along the Patagonian Andes. Surfaces of known ages (historical evidences and tree-ring analyses) were used as control sites to develop indirect lichenometric dating curves. Dating curves developed for the studied glaciers show the same general logarithmic form, indicating that growth rate of subgenus Rhizocarpon decreases over time. The strong west-east precipitation gradient across the Andean Cordillera introduces statistically significant differences in the growth curves, with faster growth rates in the moist west sites than the drier eastern sites. Latitudinal difference among the studied glaciers does not appear to be a major factor regulating lichen growth rates. Therefore, we developed two lichenometric curves for dating glacier fluctuations in wetter and drier sites in the Patagonian Andes during the past 450 yrs. Application of the developed curves to moraine dating allowed us to complement glacial chronologies previously obtained by tree-ring analyses. A first chronosequence for moraine formation in the Torrecillas Glacier (42°S) is presented. Our findings confirm the utility of lichenometry to date deglaciated surfaces in the Patagonian Andes.

  13. Knowledge and Learning in the Andes: Ethnographic Perspectives. Liverpool Latin American Studies, New Series 3.

    ERIC Educational Resources Information Center

    Stobart, Henry, Ed.; Howard, Rosaleen, Ed.

    This book presents research into the ways in which Indigenous peoples of the Andes create, transmit, maintain, and transform their knowledge, and the related processes of teaching and learning. Most chapters are based on papers delivered at a round-table conference at the University of Cambridge (England) in 1996 and include contributions from…

  14. A millennium of metallurgy recorded by lake sediments from Morococha, Peruvian Andes.

    PubMed

    Cooke, Colin A; Abbott, Mark B; Wolfe, Alexander P; Kittleson, John L

    2007-05-15

    To date, information concerning pre-Colonial metallurgy in South America has largely been limited to the archaeological record of artifacts. Here, we reconstruct a millennium of smelting activity in the Peruvian Andes using the lake-sediment stratigraphy of atmospherically derived metals (Pb, Zn, Cu, Ag, Sb, Bi, and Ti) and lead isotopic ratios (206Pb/ 207Pb) associated with smelting from the Morococha mining region in the central Peruvian Andes. The earliest evidence for metallurgy occurs ca. 1000 A.D., coinciding with the fall of the Wari Empire and decentralization of local populations. Smelting during this interval appears to have been aimed at copper and copper alloys, because of large increases in Zn and Cu relative to Pb. A subsequent switch to silver metallurgy under Inca control (ca. 1450 to conquest, 1533 A.D.) is indicated by increases in Pb, Sb, and Bi, a conclusion supported by further increases of these metals during Colonial mining, which targeted silver extraction. Rapid development of the central Andes during the 20th century raised metal burdens by an order of magnitude above previous levels. Our results represent the first evidence for pre-Colonial smelting in the central Peruvian Andes, and corroborate the sensitivity of lake sediments to pre-Colonial metallurgical activity suggested by earlier findings from Bolivia.

  15. "Nervios" and "Modern Childhood": Migration and Shifting Contexts of Child Life in the Ecuadorian Andes.

    ERIC Educational Resources Information Center

    Pribilsky, Jason

    2001-01-01

    Argues that beyond explanations predicated on psychological ideas of separation and attachment, "nervios," a depression-like disorder among children in the southern Ecuadorian Andes, reflects the limits of children's abilities to accept terms of family life increasingly defined through transnational migration and new consumption…

  16. Immune Serum Produced by DNA Vaccination Protects Hamsters against Lethal Respiratory Challenge with Andes Virus

    DTIC Science & Technology

    2008-02-01

    pulmonary syndrome in Argentina. Possibility of person to person transmission. Medicina (Buenos Aires) 56: 709–711. 8. Ferres, M., P. Vial, C. Marco, L...transmission of Andes virus. Medicina (Buenos Aires) 58(Suppl. 1):27–36. 20. Padula, P. J., A. Edelstein, S. D. Miguel, N. M. Lopez, C. M. Rossi, and R

  17. New host and lineage diversity of avian haemosporidia in the northern Andes

    PubMed Central

    Harrigan, Ryan J; Sedano, Raul; Chasar, Anthony C; Chaves, Jaime A; Nguyen, Jennifer T; Whitaker, Alexis; Smith, Thomas B

    2014-01-01

    The northern Andes, with their steep elevational and climate gradients, are home to an exceptional diversity of flora and fauna, particularly rich in avian species that have adapted to divergent ecological conditions. With this diversity comes the opportunity for parasites to exploit a wide breadth of avian hosts. However, little research has focused on examining the patterns of prevalence and lineage diversity of avian parasites in the Andes. Here, we screened a total of 428 birds from 19 species (representing nine families) and identified 133 infections of avian haemosporidia (31%), including lineages of Plasmodium, Haemoproteus, and Leucocytozoon. We document a higher prevalence of haemosporidia at higher elevations and lower temperatures, as well as an overall high diversity of lineages in the northern Andes, including the first sequences of haemosporidians reported in hummingbirds (31 sequences found in 11 species within the family Trochilidae). Double infections were distinguished using PHASE, which enables the separation of distinct parasite lineages. Results suggest that the ecological heterogeneity of the northern Andes that has given rise to a rich diversity of avian hosts may also be particularly conducive to parasite diversification and specialization. PMID:25469161

  18. Between Andes and Amazon: the genetic profile of the Arawak-speaking Yanesha.

    PubMed

    Barbieri, Chiara; Heggarty, Paul; Yang Yao, Daniele; Ferri, Gianmarco; De Fanti, Sara; Sarno, Stefania; Ciani, Graziella; Boattini, Alessio; Luiselli, Donata; Pettener, Davide

    2014-12-01

    The Yanesha are a Peruvian population who inhabit an environment transitional between the Andes and Amazonia. They present cultural traits characteristic of both regions, including in the language they speak: Yanesha belongs to the Arawak language family (which very likely originated in the Amazon/Orinoco lowlands), but has been strongly influenced by Quechua, the most widespread language family of the Andes. Given their location and cultural make-up, the Yanesha make for an ideal case study for investigating language and population dynamics across the Andes-Amazonia divide. In this study, we analyze data from high and mid-altitude Yanesha villages, both Y chromosome (17 STRs and 16 SNPs diagnostic for assigning haplogroups) and mtDNA data (control region sequences and 3 SNPs and one INDEL diagnostic for assigning haplogroups). We uncover sex-biased genetic trends that probably arose in different stages: first, a male-biased gene flow from Andean regions, genetically consistent with highland Quechua-speakers and probably dating back to Inca expansion; and second, traces of European contact consistent with Y chromosome lineages from Italy and Tyrol, in line with historically documented migrations. Most research in the history, archaeology and linguistics of South America has long been characterized by perceptions of a sharp divide between the Andes and Amazonia; our results serve as a clear case-study confirming demographic flows across that 'divide'.

  19. [Fatty acids in mature breast milk from low socioeconomic levels of Venezuelan women: influence of temperature and time of storage].

    PubMed

    Bosch, Virgilio; Golfetto, Iván; Alonso, Hilda; Laurentin, Zuly; Materan, Mercedes; García, Ninoska

    2009-03-01

    Fatty acids in mature breast milk from low socioeconomic levels of Venezuelan women: influence of temperature and time of storage. Breast milk is the main food in infants from birth until six months old. It is important to know if precarious life conditions could limit some nutrients in mother's milk. The objective of this study is to evaluate the total fat and essential long chain fatty acids in mature breast milk from low socioeconomic levels in Venezuelan women. The values of total fat (3.56 +/- 1.18 g/%) are similar that reported in the literature, however the sume of LC-PUFA n-3 was 0.3 +/- 0.04% which is related whith low n-3 fatty acid maternal diet.The sume LC-PUFA n-3 contained in this study is below most of the reviewed publications. The average amount of 22:6 n-3 in breast milk offered to newborn one month old (750 ml/day) is below estimated requirements (70 mg/day). The majority of these samples provide to the infants, the amount of DHA estimated as convenient to sustain normal growth. Also it was explored how the time (8h to 24 h) and temperatura (+4 degrees C, +15 degrees C, and +25 degrees C) can affect its composition. This data will permit to select the best condiitions of sampling and storage of mother's milk in future investigations in different regions of Venezuela. Most of the breast milk fatty acids tolerate some hours at room temperature (25 degrees C) but essential long chain fatty acids are very vulnerable. We propose that, in consequence, that samples should be transported in sterile conditions in dry ice to the laboratory in a few hours and should be kept at -70 degrees C until their analysis.

  20. Association of socioeconomic stratification with plasmatic markers of lipoperoxidation and antioxidants in Venezuelan school-age children

    PubMed Central

    Bosch, Virgilio; Giacopini, Maria Isabel

    2016-01-01

    Abstract Objetive: To establish association between socioeconomic status and plasmatic markers of lipoperoxidation and antioxidants in Venezuelan school-age children from the middle-class and in critical poverty. Methods: Cross-sectional study with a sample of 114 school-age children (aged 7-9). The socioeconomic status, dietary intake of macro and micro-nutrients, weight, height, lipid profile, indicators of lipid peroxidation and enzymatic and non-enzymatic antioxidants were determined. Results: The daily average intake of energy, carbohydrates and vitamin A, and the percentage of energy obtained from carbohydrates was significantly higher in middle-class children compared to critical poverty children (p <0.05). The circulating oxidized low density lipoprotein (p <0.001) and the susceptibility of low density lipoproteins and very low density lipoproteins to oxidation in vitro (p <0.05) were significantly higher in middle-class children, while the critical poverty children showed significantly lower levels of Vitamin C and E in plasma (p <0.05). Non-enzymatic antioxidant levels were frequently deficient in both strata. The concentrations of circulating oxidized low density lipoprotein (OR: 1.09, CI 95%: 1.016-1.179; p= 0.017) and Vitamin C (OR: 3.21, CI 95%: 1.104-9.938; p= 0.032) were associated to the socioeconomic status independently of gender, family history of premature coronary artery disease, triglicerides, Vitamin C and E dietary intake and count of white blood cells. Conclusion: The socioeconomic status was associated to circulating oxidized low density lipoprotein and Vitamin C in Venezuelan school-age children, The results suggested the need to improve the dietary intake of antioxidants in both studied socioeconomic groups. PMID:28293041

  1. Neotectonic transformation of Cenozoic fold structures in the northwestern Caucasus

    NASA Astrophysics Data System (ADS)

    Trikhunkov, Ya. I.

    2016-09-01

    The performed morphotectonic regionalization of the northwestern Caucasus shows that the fold structures directly expressed in the topography of the territory and continuing to evolve under the settings of contemporary lateral shortening predominate in the northwestern Caucasus. A map of fold structures expressed in the topography of the northwestern Caucasus is presented. The districts distinguished therein correspond to the largest regional tectonic units, the fold topography of which occurs at various stages of tectonic evolution from primary brachyanticlinal ridges of the Taman and Sochi districts to the complex fold-thrust and inversion fold ridges of the axial zone. Data on active newly formed fold and inversion structures are given. These inherited structures develop under the combined action of selective denudation, beddingplane upthrow faulting, and thrusting.

  2. Structure and Evolution of the Central Andes of Peru

    NASA Astrophysics Data System (ADS)

    Gonzalez, L.; Pfiffner, O. A.

    2009-04-01

    Three major units make up the Andes in Peru: (1) The Western Cordillera consists of the Cretaceous Coastal Batholith intruding Jurassic to Cretaceous volcaniclastics (Casma group) in the west, and a fold-and-thrust belt of Mesozoic sediments in the east. Eocene and Miocene volcanics (Calipuy group and equivalents) overly all of these rock types. (2) The Central Highland contains a folded Paleozoic-Mesozoic sedimentary sequence overlain by thick Quaternary deposits. A major fault puts Neoproterozoic basement rocks of the Eastern Cordillera next to these units. (3) In the Eastern Cordillera, Late Paleozoic clastic successions unconformably overly folded Early Paleozoic sediments and a Neoproterozoic basement in the east. Permian (locally Triassic) granitoids intruded these units and were affected by folding and thrusting. In the core of the Eastern Cordillera, Early Cretaceous overly Early or Late Paleozoic strata. To the west, a thrust belt of Paleozoic to Cenozoic strata forms the transition to the foreland of the Brasilian shield. The most external part of this thrust belt involves Pliocene sediments and is referred to as Subandine zone. The Coastal Batholith is internally undeformed. The adjacent fold-and-thrust belt to the east is characterized by tight, nearly isoclinal upright folds with amplitudes of up to 1000 m. At the surface only Cretaceous rocks are observed. Using balancing techniques, a detachment horizon at the base of the Lowermost Cretaceous (Goyallarisquizga group - Oyon Formation) can be proposed. Further east, folds are more open, asymmetric and east verging, Jurassic sediments appear in the cores of the anticlines. The abrupt change in style from upright tight folding in the west to more open folding in the east is explained by a primary difference in the depositional sequence, most probably associated with synsedimentary faulting. The overlying volcanics of the Calipuy group and equivalents are, in turn, only slightly folded. In the Northern

  3. Episodic subgreenschist facies metamorphism in the Andes of Chile - is it a valid model?

    NASA Astrophysics Data System (ADS)

    Bevins, R. E.; Robinson, D.; Aguirre, L.; Vergara, M.

    2003-04-01

    The Central Andes of Chile are characterized by subgreenschist facies burial metamorphism that is reported as having developed in up to seven episodic cycles of some 40Myr duration. The main evidence in support of the model is reported as mineralogical breaks at major stratigraphic boundaries that are interpreted as documenting sharp breaks in metamorphic grade. Here we test this model by examination of the progressive secondary mineral development, reaction progress in mafic phyllosilicates, and topological variations of the low-grade assemblages in metabasites for Jurassic to Miocene sequences east of Santiago. The mafic phyllosilicates (smectite - mixed-layer chlorite/smectite - chlorite) show increasing reaction progress with stratigraphic age and there is a continuum across the main stratigraphic boundaries, such there is no offset or gap in the reaction progress at these boundaries. There are some differences in mineral assemblages between the various stratigraphic units, such as between prehnite+pumpellyite+/-laumonite or amphibole-bearing and non amphibole bearing rocks, from which contrasting subgreenschist facies can be recognised. However, consideration of the controls on mineral parageneses at subgreenschist facies conditions demonstrates that these different facies cannot be used solely as evidence of sharp breaks in metamorphic grade at unconformities, as has been reported in many previous publications for the Andes. The presently accepted model for the Central Andes, involving repeated cycles of episodic metamorphism developing in extensional basins, is, therefore, partly unfounded. Consideration of the overall tectonic evolution of this part of the Andes concurs that the burial metamorphism developed in extensional settings, but in only two events, namely in mid-late Cretaceous and Late Miocene times respectively. The results from this work suggest that the record of sharp metamorphic breaks and the episodic model of metamorphism reported for many

  4. Geodynamics of the northern Andes: Subductions and intracontinental deformation (Colombia)

    NASA Astrophysics Data System (ADS)

    Taboada, Alfredo; Rivera, Luis A.; Fuenzalida, AndréS.; Cisternas, Armando; Philip, Hervé; Bijwaard, Harmen; Olaya, José; Rivera, Clara

    2000-10-01

    New regional seismological data acquired in Colombia during 1993 to 1996 and tectonic field data from the Eastern Cordillera (EC) permit a reexamination of the complex geodynamics of northwestern South America. The effect of the accretion of the Baudó-Panama oceanic arc, which began 12 Myr ago, is highlighted in connection with mountain building in the EC. The Istmina and Ibagué faults in the south and the Santa Marta-Bucaramanga fault to the northeast limit an E-SE moving continental wedge. Progressive indentation of the wedge is absorbed along reverse faults located in the foothills of the Cordilleras (northward of 5°N) and transpressive deformation in the Santander Massif. Crustal seismicity in Colombia is accurately correlated with active faults showing neotectonic morphological evidences. Intermediate seismicity allows to identify a N-NE trending subduction segment beneath the EC, which plunges toward the E-SE. This subduction is interpreted as a remnant of the paleo-Caribbean plateau (PCP) as suggested by geological and tomographic profiles. The PCP shows a low-angle subduction northward of 5.2°N and is limited southward by a major E-W transpressive shear zone. Normal oceanic subduction of the Nazca plate (NP) ends abruptly at the southern limit of the Baudó Range. Northward, the NP subducts beneath the Chocó block, overlapping the southern part of the PCP. Cenozoic shortening in the EC estimated from a balanced section is ˜120 km. Stress analysis of fault slip data in the EC (northward of 4°N), indicates an ˜E-SE orientation of σ1 in agreement with the PCP subduction direction. Northward, near Bucaramanga, two stress solutions were observed: (1) a late Andean N80°E compression and (2) an early Andean NW-SE compression.

  5. 40 CFR 81.126 - Northwestern Oklahoma Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Air Quality Control Regions § 81.126 Northwestern Oklahoma Intrastate Air Quality Control Region. The Northwestern Oklahoma Intrastate Air Quality Control Region consists of the territorial area encompassed by the... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Northwestern Oklahoma Intrastate...

  6. Water and sediment quality of the Lake Andes and Choteau Creek basins, South Dakota, 1983-2000

    USGS Publications Warehouse

    Sando, Steven Kent; Neitzert, Kathleen M.

    2003-01-01

    The Bureau of Reclamation has proposed construction of the Lake Andes/Wagner Irrigation Demonstration Project to investigate environmental effects of irrigation of glacial till soils substantially derived from marine shales. During 1983-2000, the U.S. Geological Survey collected hydrologic, water-quality, and sediment data in the Lake Andes and Choteau Creek Basins, and on the Missouri River upstream and downstream from Choteau Creek, to provide baseline information in support of the proposed demonstration project. Lake Andes has a drainage area of about 230 mi2 (square miles). Tributaries to Lake Andes are ephemeral. Water-level fluctuations in Lake Andes can be large, and the lake has been completely dry on several occasions. The outlet aqueduct from Lake Andes feeds into Garden Creek, which enters Lake Francis Case just upstream from Fort Randall Dam on the Missouri River. For Lake Andes tributary stations, calcium, magnesium, and sodium are approximately codominant among the cations, and sulfate is the dominant anion. Dissolved-solids concentrations typically range from about 1,000 mg/L (milligrams per liter) to about 1,700 mg/L. Major-ion concentrations for Lake Andes tend to be higher than the tributaries and generally increase downstream in Lake Andes. Proportions of major ions are similar among the different lake units (with the exception of Owens Bay), with calcium, magnesium, and sodium being approximately codominant among cations, and sulfate being the dominant anion. Owens Bay is characterized by a calcium sulfate water type. Dissolved-solids concentrations for Lake Andes typically range from about 1,400 to 2,000 mg/L. Whole-water nitrogen and phosphorus concentrations are similar among the Lake Andes tributaries, with median whole-water nitrogen concentrations ranging from about 1.6 to 2.4 mg/L, and median whole-water phosphorus concentrations ranging from about 0.5 to 0.7 mg/L. Whole-water nitrogen concentrations in Lake Andes are similar among the

  7. Evaluation of vascular clearance as a marker for virulence of alphaviruses: disassociation of rapid clearance with low virulence of venezuelan encephalitis virus strains in guinea pigs.

    PubMed Central

    Jahrling, P B; Heisey, G B; Hesse, R A

    1977-01-01

    The concept that relates low virulence of certain alphaviruses to low viremia and efficient vascular clearance of virus was tested in guinea pigs. Previously published studies with hamsters suggested that virulent strains maintain high viremias primarily because they are cleared inefficiently from the blood. In the present study, with guinea pigs, six of six virulent strains of Venezuelan encephalitis virus were cleared inefficiently, whereas three of six nonlethal or benign virus strains were cleared rapidly. However, three other guinea pig-benign Venezuelan encephalitis virus strains cleared slowly, to produce a high viremia was correlated with inefficient growth in primary viral replication sites. Thus, the potential of some alphaviruses to produce destructive lesions may be restricted by efficient clearance of virus from the blood, whereas the growth of other benign alphavirus strains may be restricted after the virus is presented to target cells. PMID:892910

  8. The Guyana-Venezuela Border Dispute: An Analysis of the Reasons Behind Venezuela’s Continuing Demands for Abrogation of the 1899 Anglo-Venezuelan Arbitral Treaty

    DTIC Science & Technology

    1992-01-01

    occupation" of Santo Thome de Guayana by the Spaniards (Daly. 1985: 44-48). I II 10 The Spanish continued to monitor Dutch activities and interests in...territory by continuously opposing efforts by Guyana to obtain financial. support. for the implementation of projects vital to her economic development. The...order to accurately evaluate this U decision it is vital to understand which issues were consuming the Venezuelan people during that time. It would be

  9. The Largest Holocene Eruption of the Central Andes Found

    NASA Astrophysics Data System (ADS)

    Fernandez-Turiel, J.; Rodriguez-Gonzalez, A.; Saavedra, J.; Perez-Torrado, F.; Carracedo, J.; Osterrieth, M.; Carrizo, J.; Esteban, G.

    2013-12-01

    We present new data and interpretation about a major eruption -spreading ˜110 km3 ashes over 440.000 km2- long thought to have occurred around 4200 years ago in the Cerro Blanco Volcanic Complex (CBVC) in NW Argentina. This eruption may be the biggest during the past five millennia in the Central Volcanic Zone of the Andes, and possibly one of the largest Holocene eruptions in the world. The environmental effects of this voluminous eruption are still noticeable, as evidenced by the high content of arsenic and other trace elements in the groundwaters of the Chacopampean Plain. The recognition of this significant volcanic event may shed new light on interpretations of critical changes observed in the mid-Holocene paleontological and archaeological records, and offers researchers an excellent, extensive regional chronostratigraphic marker for reconstructing mid-Holocene geological history over a wide geographical area of South America. More than 100 ashes were sampled in Argentina, Chile and Uruguay during different field campaigns. Ash samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), grain size distributions laser diffraction, and geochemically by electron microprobe (EMPA) and laser ablation-HR-ICP-MS. New and published 14C ages were calibrated to calendar years BP. The age of the most recent CBVC eruption is 4407-4093 cal y BP, indirectly dated by 14C of associated organic sediment within the lower part of a proximal fall deposit of this event (26°53'16.05"S-67°44'48.68"W). This is the youngest record of a major volcanic event in the Southern Puna. This age is consistent with other radiocarbon dates of organic matter in palaeosols underlying or overlying distal ash fall deposits. Based on their products, all of rhyolitic composition, we have distinguished 8 main episodes during the evolution of the most recent CBVC eruption: 1) the eruption began with a white rhyolite lava dome extrusion; 2) followed by a Plinian

  10. Volcanological evolution of Paniri volcano, Central Andes, northern Chile

    NASA Astrophysics Data System (ADS)

    Lazcano, J.; Godoy, B.; Aguilera, F.; Wilke, H.

    2012-12-01

    San Pedro-Linzor volcanic chain (SPLVC) is located between 21°45'S-22°15'S, in the Recent volcanic arc of Central Andes. This volcanic chain comprises several volcanic edifices and dacitic domes, with a total lenght of ~65 km. Volcanic structures distributed in SPLVC show a NW-SE trending orientation and have been been built over Miocene ignimbrite fields. Paniri volcano (5946 m a.s.l.) is a composite stratovolcano located in SPLVC, and distributes southwards San Pedro - San Pablo volcanic complex, at the northern side of Chao Dacite. In this work, the volcanological evolution of Paniri is presented. This volcanic edifice is constituted by two cones, generated during four stages. The first stage corresponds to the plateau-type stage consituted by extensive andesitic and basaltic-andesite lavas and scoria flows that overlie the ignimbritic basement of the volcano. Over these mafic flows, thick dacitic flows were erupted at the northern, southern and southwestern flank of the volcano. After this stage, the main edifice was constructed, presenting two stages: the Old and the Young Cone. The Old Cone Stage was built on the southern part of the volcano. It is constituted by andesitic-to-dacitic lavas and pyroclastic flows. After that, lavic and pyroclastic flows were erupted north of the Old Cone, generating the Young Cone Stage, corresponding to lavas and pyroclastic flows that overlay the previous Old Cone. Composition of the flows of this stage vary from basaltic-andesite to dacite. An 40Ar/39Ar radiometric measure from an basaltic-andesite lava flow of the Young Cone Stage gave a plateau age of 400±50 ka. Significant dissection by glacial erosion affect southern flank of old cone and diverse parts of young cone, being in the last less pervasive. Frontal and lateral morraines deposits are present in the related glacial valleys. The last stage in the evolution of this volcano corresponds to emision of andesitic flows, with autobreccia textures. These flows reach up

  11. Screening for new accumulator plants in Andes Range mines

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Roca, Núria

    2016-04-01

    accumulated considerable concentrations of Cu and Zn. The species from the genus Bidens (Asteraceae) were able not only to accumulate high shoot As concentrations (> 1000 μg g-1 in B. cynapiifolia from Peru) but also considerable amounts of Pb (B. humilis from Chile). The highest Cu shoot concentrations were found in Mullinum spinosum (870 μg g-1) and in B. cynapiifolia (620 μg g-1). The shoot accumulation of Zn was highest in Baccharis amdatensis (>1900 μg g-1) and in Rumex crispus (1300 μg g-1) from the Ag mine in Ecuador (Bech et al., 2002). In the Peruvian Andes, B. triplinervia can be considered interesting for phytostabilization, due to its capacity to restrict the accumulation of elevated amounts of Pb and Zn in the shoots.

  12. Hantaan/Andes virus DNA Vaccine Elicits a Broadly Cross-Reactive Neutralizing Antibody Response in Nonhuman Primates

    DTIC Science & Technology

    2006-01-01

    pulmonary syndrome (HPS). The most prevalent and lethal hantaviruses associated with HFRS and HPS are Hantaan virus (HTNV) and Andes virus (ANDV...Published by Elsevier Inc.Keywords: Hantavirus; DNA vaccine; Hantaan virus; Andes virus; Neutralizing antibodiesIntroduction Hantaviruses are rodent...borne viruses that cause hemor- rhagic fever in humans. Different hantaviruses are associated with different disease syndromes with varying degrees of

  13. Discrimination of Venezuelan spirituous beverages by a trace element-radial basis neural network approach.

    PubMed

    Hernández-Caraballo, Edwin A; Avila de Hernández, Rita M; Rivas-Echeverría, Francklin; Capote-Luna, Tarcisio

    2008-01-15

    Radial basis neural networks (RBNNs) were developed and evaluated for discrimination of specimens of 'aguardiente de Cocuy', a spirituous beverage produced in the northwestern region of Venezuela. The beverage is distilled from the must of Agave cocui Trelease in an artisanship fashion with little quality control. Forty specimens, with known concentrations of copper, iron, and zinc, were used in this study. The specimens were previously collected in various locations around Sucre Municipality (Falcón State) and Urdaneta Municipality (Lara State). The normalized concentrations of these elements served as indirect descriptors of origin (input data). They were presented to the neural networks through 1-3 input nodes in seven different combinations. In addition, two categories (two collection sites) and four categories (two collection sites+two manufacturing conditions) were designated as output data, in order to assess the impact of such selection on the discrimination performance. The overall performance of the four-category RBNNs was as follows (the input data is indicated in parentheses): (Cu-Fe)>(Cu-Zn)>(Cu)>(Zn)>(Fe-Zn)>(Cu-Fe-Zn)>(Fe). In this case, the highest percentage of correct hits was 82.5%. For the two-category RBNNs, the performance decreased as indicated below: (Cu)>(Cu-Fe)>(Cu-Zn)>(Fe-Zn)>(Zn) approximately (Cu-Fe-Zn)>(Fe). The reduction in the number of categories led to an increase in the discrimination performance of all the RBNNs, the best of which was 90.0%. The possibility of discriminating specimens of 'aguardiente de Cocuy' with such an accuracy, based on a single-element determination, is particularly attractive as it would result in a reduction of analysis' costs and laboratory's response time.

  14. Current state of glaciers in the tropical Andes: a perspective on glacier evolution and climate change

    NASA Astrophysics Data System (ADS)

    Rabatel, Antoine; Francou, Bernard; Soruco, Alvaro; Gomez, Jesus; Caceres, Bolivar; Ceballos, Jorge-Luis; Vuille, Mathias; Sicart, Jean-Emmanuel; Huggel, Christian

    2013-04-01

    This presentation provides a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the LIA (mid 17th - early 18th century). In terms of changes in mass balance, although there have been some sporadic gains on several glaciers, we show that the trend has been quite negative over the past 50 years, with a mean mass balance deficit for glaciers in the tropical Andes that is slightly more negative than the one computed on a global scale. A break point in the trend appeared in the late 1970s with mean annual mass balance per year decreasing from -0.2 m w.e. in the period 1964-1975 to -0.76 m w.e. in the period 1976-2010. In addition, even if glaciers are currently retreating everywhere in the tropical Andes, it should be noted that this is much more pronounced on small glaciers at low altitudes that do not have a permanent accumulation zone, and which could disappear in the coming years/decades. Monthly mass balance measurements performed in Bolivia, Ecuador and Colombia show that variability of the surface temperature of the Pacific Ocean is the main factor governing variability of the mass balance at the decadal time scale. Precipitation did not display a significant trend in the tropical Andes in the 20th century, and consequently cannot explain the glacier recession. On the other hand, temperature increased at a significant rate of 0.10°C/decade in the last 70 years. The higher frequency of El Niño events and changes in its spatial and temporal occurrence since the late 1970s together with a warming troposphere over the tropical Andes may thus explain much of the recent dramatic shrinkage of glaciers in this part of the world.

  15. The Center for Talent Development at Northwestern University

    ERIC Educational Resources Information Center

    Olszewski-Kubilius, Paula

    2004-01-01

    During the summer and on weekends, it is not unusual to see many children, the youngest holding their parents' hands, walking to classes amongst the beautiful landscaping and old buildings of Northwestern University on Lake Michigan's shores in Evanston, Illinois. The Center for Talent Development (CTD) has been offering services and programs to…

  16. Beak deformities in Northwestern Crows: evidence of a multispecies epizootic

    USGS Publications Warehouse

    Van Hemert, Caroline; Handel, Colleen M.

    2010-01-01

    Beak abnormalities are rare among adult birds and, typically, are not widespread in a given population, within a region, or across multiple species. A high concentration of beak deformities was recently documented in Black-capped Chickadees (Poecile atricapillus) and other resident avian species in Alaska. We describe a parallel condition in Northwestern Crows (Corvus caurinus) that signals the emergence of a multispecies epizootic. On the basis of 186 Northwestern Crows captured at six sites in Alaska during 2007 and 2008, we estimated the prevalence of beak deformities in adults to be 16.9 ± 5.3%, the highest rate of gross deformities ever recorded in a wild bird population. Prevalence varied among sites and was as high as 36% on the Kenai Peninsula, which suggests possible epizootic clusters. We also documented beak abnormalities in an additional 148 Northwestern Crows in south-central and southeastern Alaska and in 64 crows near Vancouver, British Columbia, and Puget Sound, Washington, a region where both Northwestern Crows and American Crows (C. brachyrhynchos) occur. The increase in frequency and distribution of crows observed with abnormal beaks throughout the Pacific Northwest since the late 1990s indicates a geographic expansion of this problem. Affected crows exhibited elongated and often crossed beaks that were morphologically similar to deformities documented in Black-capped Chickadees and other species in Alaska over approximately the same period. Additional research is needed to determine the etiology and potential adverse effects on bird populations affected by this disorder.

  17. Capturing Qualitative Data: Northwestern University Special Libraries' Acknowledgments Database

    ERIC Educational Resources Information Center

    Stigberg, Sara; Guittar, Michelle; Morse, Geoffrey

    2015-01-01

    Assessment and supporting data have become of increasing interest in librarianship. In this paper, we describe the development and implementation of the Northwestern University Library Acknowledgments Database tool, which gathers and documents qualitative data, as well as its component reporting function. This collaborative project and resulting…

  18. Northwestern Argentina as seen from the Apollo 7 spacecraft

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Puna de Atacama area of northwestern Argentina, Provinces of Salta and Catamarca, as seen from the Apollo 7 spacecraft during its 154th revolution of the earth. Photographed from an altitude of 175 nautical miles, at ground elapsed time of 243 hours and 58 minutes.

  19. Emergence of African swine fever virus, northwestern Iran.

    PubMed

    Rahimi, Pooneh; Sohrabi, Amir; Ashrafihelan, Javad; Edalat, Rosita; Alamdari, Mehran; Masoudi, Mohammadhossein; Mostofi, Saied; Azadmanesh, Kayhan

    2010-12-01

    In 2008, African swine fever was introduced into Georgia, after which it spread to neighboring Armenia, Azerbaijan, and the Russian Federation. That same year, PCR and sequence analysis identified African swine fever virus in samples from 3 dead female wild boars in northwestern Iran. Wild boars may serve as a reservoir.

  20. Interseismic Rates From the CTO cGPS Andes and Nepal Networks

    NASA Astrophysics Data System (ADS)

    Genrich, J. F.; Galetzka, J.; Chowdhury, F.; Avouac, J.; Simons, M.; Barrientos, S. E.; Comte, D.; Norabuena, E. O.; Sapkota, S. N.

    2009-12-01

    To study crustal deformation at converging plate margins the Caltech Tectonics Observatory (CTO), together with partner institutions in the host countries, operates continuously observing GPS stations in the central Andes (northern Chile and southern Peru) and in Nepal. The currently 20-site Andes network was established in 2005 with 7 stations. Efforts are underway to provide data streaming links at near real time for the majority of sites. The Nepal network started with 10 sites in 2004 and has been expanded to 23 sites in the last couple of years. Dual frequency code and phase data from all sites are processed with the GAMIT/GLOBK processing package. Reliable interseismic velocities are now available for the majority of sites. Network metadata, rinex data files, processed time series and velocity estimates can be found online thru links at the CTO website: tectonics.caltech.edu.

  1. Illicit crops and armed conflict as constraints on biodiversity conservation in the Andes region.

    PubMed

    Fjeldså, Jon; Alvarez, María D; Lazcano, Juan Mario; León, Blanca

    2005-05-01

    Coca, once grown for local consumption in the Andes, is now produced for external markets, often in areas with armed conflict. Internationally financed eradication campaigns force traffickers and growers to constantly relocate, making drug-related activities a principal cause of forest loss. The impact on biodiversity is known only in general terms, and this article presents the first regional analysis to identify areas of special concern, using bird data as proxy. The aim of conserving all species may be significantly constrained in the Santa Marta and Perijá mountains, Darién, some parts of the Central Andes in Colombia, and between the middle Marañón and middle Huallaga valleys in Peru. Solutions to the problem must address the root causes: international drug markets, long-lasting armed conflict, and lack of alternative income for the rural poor.

  2. Climate change and water resources in arid mountains: an example from the Bolivian Andes.

    PubMed

    Rangecroft, Sally; Harrison, Stephan; Anderson, Karen; Magrath, John; Castel, Ana Paola; Pacheco, Paula

    2013-11-01

    Climate change is projected to have a strongly negative effect on water supplies in the arid mountains of South America, significantly impacting millions of people. As one of the poorest countries in the region, Bolivia is particularly vulnerable to such changes due to its limited capacity to adapt. Water security is threatened further by glacial recession with Bolivian glaciers losing nearly half their ice mass over the past 50 years raising serious water management concerns. This review examines current trends in water availability and glacier melt in the Bolivian Andes, assesses the driving factors of reduced water availability and identifies key gaps in our knowledge of the Andean cryosphere. The lack of research regarding permafrost water sources in the Bolivian Andes is addressed, with focus on the potential contribution to mountain water supplies provided by rock glaciers.

  3. The ANDES Deep Underground Laboratory in South America: status and prospects

    NASA Astrophysics Data System (ADS)

    Bertou, Xavier

    2017-01-01

    The construction of the Agua Negra tunnel through the Andes between Argentina and Chile is a unique opportunity to build a world class deep underground laboratory in the southern hemisphere, with 1750 m of rock overburden. At 30 degrees latitude south, far from nuclear power plants, it provides a unique site for Dark Matter searches and Neutrino experiments, and can host multidisciplinary experiments with a specific focus on Earth sciences given its location in a peculiar geoactive region. Its operation is foreseen to be coordinated by an international consortium and to start in 2026. In this presentation the current status of the Agua Negra tunnel and the ANDES initiative will be reviewed, and the scientific programme of the planned laboratory will be discussed.

  4. Surface uplift in the Central Andes driven by growth of the Altiplano Puna Magma Body

    NASA Astrophysics Data System (ADS)

    Perkins, Jonathan P.; Ward, Kevin M.; de Silva, Shanaka L.; Zandt, George; Beck, Susan L.; Finnegan, Noah J.

    2016-10-01

    The Altiplano-Puna Magma Body (APMB) in the Central Andes is the largest imaged magma reservoir on Earth, and is located within the second highest orogenic plateau on Earth, the Altiplano-Puna. Although the APMB is a first-order geologic feature similar to the Sierra Nevada batholith, its role in the surface uplift history of the Central Andes remains uncertain. Here we show that a long-wavelength topographic dome overlies the seismically measured extent of the APMB, and gravity data suggest that the uplift is isostatically compensated. Isostatic modelling of the magmatic contribution to dome growth yields melt volumes comparable to those estimated from tomography, and suggests that the APMB growth rate exceeds the peak Cretaceous magmatic flare-up in the Sierran batholith. Our analysis reveals that magmatic addition may provide a contribution to surface uplift on par with lithospheric removal, and illustrates that surface topography may help constrain the magnitude of pluton-scale melt production.

  5. The SD1 Subdomain of Venezuelan Equine Encephalitis Virus Capsid Protein Plays a Critical Role in Nucleocapsid and Particle Assembly

    PubMed Central

    Reynaud, Josephine M.; Lulla, Valeria; Kim, Dal Young; Frolova, Elena I.

    2015-01-01

    ABSTRACT Venezuelan equine encephalitis virus (VEEV) is an important human and animal pathogen, for which no safe and efficient vaccines or therapeutic means have been developed. Viral particle assembly and budding processes represent potential targets for therapeutic intervention. However, our understanding of the mechanistic process of VEEV assembly, RNA encapsidation, and the roles of different capsid-specific domains in these events remain to be described. The results of this new study demonstrate that the very amino-terminal VEEV capsid-specific subdomain SD1 is a critical player in the particle assembly process. It functions in a virus-specific mode, and its deletion, mutation, or replacement by the same subdomain derived from other alphaviruses has strong negative effects on infectious virus release. VEEV variants with mutated SD1 accumulate adaptive mutations in both SD1 and SD2, which result in a more efficiently replicating phenotype. Moreover, efficient nucleocapsid and particle assembly proceeds only when the two subdomains, SD1 and SD2, are derived from the same alphavirus. These two subdomains together appear to form the central core of VEEV nucleocapsids, and their interaction is one of the driving forces of virion assembly and budding. The similar domain structures of alphavirus capsid proteins suggest that this new knowledge can be applied to other alphaviruses. IMPORTANCE Alphaviruses are a group of human and animal pathogens which cause periodic outbreaks of highly debilitating diseases. Despite significant progress made in understanding the overall structure of alphavirus and VEEV virions, and glycoprotein spikes in particular, the mechanistic process of nucleocapsid assembly, RNA encapsidation, and the roles of different capsid-specific domains in these processes remain to be described. Our new data demonstrate that the very amino-terminal subdomain of Venezuelan equine encephalitis virus capsid protein, SD1, plays a critical role in the

  6. Assessment of future regional precipitation pattern for an Andes region in Southern Peru

    NASA Astrophysics Data System (ADS)

    Salzmann, N.; Rohrer, M.; Acuna, D.; Calanca, P.; Huggel, C.

    2012-04-01

    The Cusco and Apurímac region (Southern Peru) in the outer tropical Andes is characterized by a distinct wet and dry season. The climatology of the Andes region in southern Peru is complex and mainly influenced by tropical and extra tropical upper level-large scale circulation as well as by local convection. For the past decades, observations from station data show a slight negative precipitation trend for the area. Scenarios for the future are associated with large uncertainties. Data from the few available Regional Climate Model simulations, and results from statistical downscaling show neither clear nor consistent future precipitation trends for this region The large biodiversity in the high altitude of the Andes and the critical socio-economic situation of the majority of the local population imply a high vulnerability to climate variability and change. Even small shifts in particular in the precipitation regime (sum, frequency or intensity) can therefore have significant impacts on the livelihood of the rural population. Droughts and flooding events that occurred in the past years have demonstrated the heavy repercussion of extreme events. In our study, we analysed and correlated past regional station observations with large-scale circulation patterns from Renanalyses in order to aim at improving our understanding of the major drivers for precipitation in the Cusco-Apurímac region. First results show an only moderate correlation with ENSO and a relative stronger correlation with moisture transported from the Amazon Basin. Our results are then related to large-scale pattern scenarios provided by GCMs and discussed in view of possible impacts of climate change for the Cusco - Apurímac region. In conclusion, we aim at showing at the example of this specific area of the Andes how process knowledge can be used to support the development of adaptation measures in regions with limited availability of data.

  7. Foreland shortening and crustal balancing in the Andes at 30°S latitude

    NASA Astrophysics Data System (ADS)

    Allmendinger, R. W.; Figueroa, D.; Synder, D.; Beer, J.; Mpodozis, C.; Isaacks, B. L.

    1990-08-01

    Excellent surface exposures, known Benioff zone geometry, a dynamic morphology, and the availability of industry seismic reflection data all make the Andes at 30°S an excellent transect for investigating crustal-scale balanced sections. 150-170 km of horizontal shortening has occurred in three major belts located between the trench and the foreland. The thin-skinned, east-verging Precordillera of western Argentina accounts for 60-75% of the total shortening and formed mostly since major volcanism ceased at ˜10 Ma. Industry seismic reflection data show that the décollement of the Precordillera belt is located anomalously deep at ˜15 km. The belt is dominated by fault propagation folds and contains several prominent out-of-sequence thrust faults. Seismic stratigraphie analysis shows that Miocene strata in the Iglesia Valley, located between the Precordillera and the crest of the Andes, accumulated in a piggy-back basin. Onlap relations on the western side indicate that the High Cordillera was uplifted as a major fault bend fold over a buried ramp. Thrusting in the two western belts, both in the High Cordillera of Chile, formed during the waning stages of arc volcanism, 11-16 Ma. and account for 25-40% of the shortening. The observed shortening is probably greater than can be accounted for with reasonable crustal thicknesses, indicating the possibility of continental truncation or erosion along the plate margin or an anomalously thick root held down by the nearly flat subducted Nazca Plate. Our preferred crustal geometry puts the ramp between upper and lower crustal deformation west of the high topography, requiring crustal scale tectonic wedging to thicken the crust beneath the crest of the Andes. This non-unique model provides a simple explanation of the first order morphology of the Andes at this latitude.

  8. A new species of Platydecticus (Orthoptera: Tettigoniidae: Tettigoniinae; Nedubini) from the Andes of Chile.

    PubMed

    Sánchez, Alejandro Vera

    2015-11-10

    A new species of the genus Platydecticus is described based on adult male and female specimens and the egg. The new species, Platydecticus diaguita, inhabits the Andes Range at 27º S latitude, above 3000 m elevation. Both sexes are easily identifiable by genital morphology characters and by the external characters of the fastigium of the vertex and the reduced number of spines in the hind tibia. It is also the smallest species described for the genus.

  9. Climate in the Western Cordillera of the Central Andes over the last 4300 years

    NASA Astrophysics Data System (ADS)

    Engel, Zbyněk; Skrzypek, Grzegorz; Chuman, Tomáš; Šefrna, Luděk; Mihaljevič, Martin

    2014-09-01

    The Distichia peat core obtained in the Carhuasanta valley near Nevado Mismi, Cordillera Chila, provides information on climatic and environmental conditions over the last ˜4300 years. The relative changes in the stable carbon isotope composition of plant remains preserved in the core reflect major temperature fluctuations in the Western Cordillera of the southern Peruvian Andes. These temperature variations can be additionally linked with the changes in precipitation patterns by analysing C% and C/N ratio in the core. Relatively warm and moist conditions prevailed from 4280 to 3040 cal. yrs BP (BC 2330-1090) with a short colder dry episode around 3850 cal. yrs BP (BC 1900). The most prominent climate changes recorded in the peat occurred between 3040 and 2750 cal. yrs BP (BC 1090-800) when the initial warming turned to a rapid cooling to temperatures at least 2 °C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP (BC 830) when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes matching the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years when an extended warm and relatively humid period occurred between 640 and 155 cal. yrs BP (AD 1310-1795) followed by predominantly colder and drier conditions. The established δ13C peat record represents the first continuous proxy for the temperature in the southern Peruvian Andes dated by the AMS 14C. Distichia peat is wide spread in the Andes and the proposed approach can be applied elsewhere in high altitudes, where no other traditional climate proxies are available.

  10. Two new species of Siphocampylus (Campanulaceae, Lobelioideae) from the Central Andes

    PubMed Central

    Lagomarsino, Laura P.; Santamaría-Aguilar, Daniel

    2016-01-01

    Abstract Two species of Siphocampylus (Campanulaceae: Lobelioideae) from the Central Andes of Peru and Bolivia are described, illustrated, and discussed with reference to related species. One species, Siphocampylus antonellii, is endemic to high elevation grasslands of Calca, Peru, while the second, Siphocampylus siberiensis, is endemic to cloud forests of Cochabamba, Bolivia. Both species are robust shrubs that produce tubular pink flowers that are likely pollinated by hummingbirds. PMID:26884710

  11. Miocene orographic uplift forces rapid hydrological change in the southern central Andes

    PubMed Central

    Rohrmann, Alexander; Sachse, Dirk; Mulch, Andreas; Pingel, Heiko; Tofelde, Stefanie; Alonso, Ricardo N.; Strecker, Manfred R.

    2016-01-01

    Rainfall in the central Andes associated with the South American Monsoon and the South American Low-Level Jet results from orographic effects on atmospheric circulation exerted by the Andean Plateau and the Eastern Cordillera. However, despite its importance for South American climate, no reliable records exist that allow decoding the evolution of thresholds and interactions between Andean topography and atmospheric circulation, especially regarding the onset of humid conditions in the inherently dry southern central Andes. Here, we employ multi-proxy isotope data of lipid biomarkers, pedogenic carbonates and volcanic glass from the Eastern Cordillera of NW Argentina and present the first long-term evapotranspiration record. We find that regional eco-hydrology and vegetation changes are associated with initiation of moisture transport via the South American Low-Level Jet at 7.6 Ma, and subsequent lateral growth of the orogen at 6.5 Ma. Our results highlight that topographically induced changes in atmospheric circulation patterns, not global climate change, were responsible for late Miocene environmental change in this part of the southern hemisphere. This suggests that mountain building over time fundamentally controlled habitat evolution along the central Andes. PMID:27767043

  12. The Irish potato famine pathogen Phytophthora infestans originated in central Mexico rather than the Andes

    PubMed Central

    Goss, Erica M.; Tabima, Javier F.; Cooke, David E. L.; Restrepo, Silvia; Fry, William E.; Forbes, Gregory A.; Fieland, Valerie J.; Cardenas, Martha; Grünwald, Niklaus J.

    2014-01-01

    Phytophthora infestans is a destructive plant pathogen best known for causing the disease that triggered the Irish potato famine and remains the most costly potato pathogen to manage worldwide. Identification of P. infestan’s elusive center of origin is critical to understanding the mechanisms of repeated global emergence of this pathogen. There are two competing theories, placing the origin in either South America or in central Mexico, both of which are centers of diversity of Solanum host plants. To test these competing hypotheses, we conducted detailed phylogeographic and approximate Bayesian computation analyses, which are suitable approaches to unraveling complex demographic histories. Our analyses used microsatellite markers and sequences of four nuclear genes sampled from populations in the Andes, Mexico, and elsewhere. To infer the ancestral state, we included the closest known relatives Phytophthora phaseoli, Phytophthora mirabilis, and Phytophthora ipomoeae, as well as the interspecific hybrid Phytophthora andina. We did not find support for an Andean origin of P. infestans; rather, the sequence data suggest a Mexican origin. Our findings support the hypothesis that populations found in the Andes are descendants of the Mexican populations and reconcile previous findings of ancestral variation in the Andes. Although centers of origin are well documented as centers of evolution and diversity for numerous crop plants, the number of plant pathogens with a known geographic origin are limited. This work has important implications for our understanding of the coevolution of hosts and pathogens, as well as the harnessing of plant disease resistance to manage late blight. PMID:24889615

  13. Toxoplasma gondii and Neospora caninum seroprevalences in domestic South American camelids of the Peruvian Andes.

    PubMed

    Chávez-Velásquez, Amanda; Aguado-Martínez, Adriana; Ortega-Mora, Luis M; Casas-Astos, Eva; Serrano-Martínez, Enrique; Casas-Velásquez, Gina; Ruiz-Santa-Quiteria, Jose A; Alvarez-García, Gema

    2014-10-01

    The objective of this study was to investigate the presence of Toxoplasma gondii- and Neospora caninum-specific antibodies in domestic South American camelids (SAC) (llamas and alpacas) from the Peruvian Andes through a cross-sectional study. A wide panel of serum samples collected from 1,845 llamas and 2,874 alpacas from the two main SAC production areas of Peru was selected. Immunofluorescence antibody technique was employed to detect and titrate specific anti-T. gondii and anti-N. caninum immunoglobulins G in serum samples. The association between T. gondii and N. caninum seroprevalence and the geographical origin (Central and South Peruvian Andes) was evaluated. Anti-T. gondii antibodies were found in 460 (24.9 %) llamas and 706 (24.6 %) alpacas, whereas anti-N. caninum antibodies were detected in 153 (8.3 %) llamas and 425 (14.8 %) alpacas. Toxoplasma gondii infection was strongly associated with the South Peruvian Andes where moderate climate conditions, larger human population, compared to the Central region, and the presence of wildlife definitive hosts could favor horizontal transmission to SAC. In contrast, N. caninum infection was not associated with the geographical region. These results indicate that T. gondii and N. caninum infections are highly and moderately widespread, respectively, in both species of domestic SAC studied in the sampled areas and appropriate control measures should be undertaken to reduce the prevalence of both parasitic infections.

  14. Airborne Imaging Spectroscopy of Forest Canopy Chemistry in the Andes-Amazon Corridor

    NASA Astrophysics Data System (ADS)

    Martin, R.; Anderson, C.; Knapp, D. E.; Asner, G. P.

    2013-12-01

    The Andes-Amazon corridor is one of the most biologically diverse regions on Earth. Elevation gradients provide opportunities to explore the underlying sources and environmental controls on functional diversity of the forest canopy, however plot-based studies have proven highly variable. We used airborne imaging spectroscopy from the Carnegie Airborne Observatory (CAO) Airborne Taxonomic Mapping System (AToMS) to quantify changes canopy functional traits in a series of eleven 25-ha landscapes distributed along a 3300 m elevation gradient from lowland Amazonia to treeline in the Peruvian Andes. Each landscape encompassed a 1 ha field plot in which all trees reaching the canopy were climbed and leaves were sampled for 20 chemical traits. We used partial least squares regression to relate plot-level chemical values with airborne spectroscopy from the 1 ha area. Sixteen chemical traits produced predictable relationships with the spectra and were used to generate maps of the 25 ha landscape. Ten chemical traits were significantly related to elevation at the 25 ha scale. These ten traits displayed 35% greater accuracy (R2) and precision (rmse) when evaluated at the 25 ha scale compared to values derived from tree climbing alone. The results indicate that high-fidelity imaging spectroscopy can be used as surrogate for laborious tree climbing and chemical assays to understand chemical diversity in Amazonian forests. Understanding how these chemicals vary among forest communities throughout the Andes-Amazon corridor will facilitate mapping of functional diversity and the response of canopies to climate change.

  15. Calculated WIMP signals at the ANDES laboratory: comparison with northern and southern located dark matter detectors

    NASA Astrophysics Data System (ADS)

    Civitarese, O.; Fushimi, K. J.; Mosquera, M. E.

    2016-12-01

    Weakly interacting massive particles (WIMPs) are possible components of the Universe’s dark matter (DM). The detection of WIMPs is signaled by the recoil of the atomic nuclei which form a detector. CoGeNT at the Soudan Underground Laboratory (SUL) and DAMA at the Laboratori Nazionali del Gran Sasso (LNGS) have reported data on annual modulation of signals attributed to WIMPs. Both experiments are located in laboratories in the Northern Hemisphere. DM detectors are planned to operate (or already operate) in laboratories in the Southern Hemisphere, including SABRE at Stawell Underground Physics Laboratory (SUPL) in Australia, and DM-ICE in Antarctica. In this work we have analyzed the dependence of diurnal and annual modulation of signals, pertaining to the detection of WIMP, on the coordinates of the laboratory, for experiments which may be performed in the planned new Agua Negra Deep Experimental Site (ANDES) underground facility, to be built in San Juan, Argentina. We made predictions for NaI and Ge-type detectors placed in ANDES, to compare with DAMA, CoGeNT, SABRE and DM-ICE arrays, and found that the diurnal modulation of the signals, at the ANDES site, is amplified at its maximum value, both for NaI (Ge)-type detectors, while the annual modulation remains unaffected by the change in coordinates from north to south.

  16. Miocene orographic uplift forces rapid hydrological change in the southern central Andes

    NASA Astrophysics Data System (ADS)

    Rohrmann, Alexander; Sachse, Dirk; Mulch, Andreas; Pingel, Heiko; Tofelde, Stefanie; Alonso, Ricardo N.; Strecker, Manfred R.

    2016-10-01

    Rainfall in the central Andes associated with the South American Monsoon and the South American Low-Level Jet results from orographic effects on atmospheric circulation exerted by the Andean Plateau and the Eastern Cordillera. However, despite its importance for South American climate, no reliable records exist that allow decoding the evolution of thresholds and interactions between Andean topography and atmospheric circulation, especially regarding the onset of humid conditions in the inherently dry southern central Andes. Here, we employ multi-proxy isotope data of lipid biomarkers, pedogenic carbonates and volcanic glass from the Eastern Cordillera of NW Argentina and present the first long-term evapotranspiration record. We find that regional eco-hydrology and vegetation changes are associated with initiation of moisture transport via the South American Low-Level Jet at 7.6 Ma, and subsequent lateral growth of the orogen at 6.5 Ma. Our results highlight that topographically induced changes in atmospheric circulation patterns, not global climate change, were responsible for late Miocene environmental change in this part of the southern hemisphere. This suggests that mountain building over time fundamentally controlled habitat evolution along the central Andes.

  17. Miocene orographic uplift forces rapid hydrological change in the southern central Andes.

    PubMed

    Rohrmann, Alexander; Sachse, Dirk; Mulch, Andreas; Pingel, Heiko; Tofelde, Stefanie; Alonso, Ricardo N; Strecker, Manfred R

    2016-10-21

    Rainfall in the central Andes associated with the South American Monsoon and the South American Low-Level Jet results from orographic effects on atmospheric circulation exerted by the Andean Plateau and the Eastern Cordillera. However, despite its importance for South American climate, no reliable records exist that allow decoding the evolution of thresholds and interactions between Andean topography and atmospheric circulation, especially regarding the onset of humid conditions in the inherently dry southern central Andes. Here, we employ multi-proxy isotope data of lipid biomarkers, pedogenic carbonates and volcanic glass from the Eastern Cordillera of NW Argentina and present the first long-term evapotranspiration record. We find that regional eco-hydrology and vegetation changes are associated with initiation of moisture transport via the South American Low-Level Jet at 7.6 Ma, and subsequent lateral growth of the orogen at 6.5 Ma. Our results highlight that topographically induced changes in atmospheric circulation patterns, not global climate change, were responsible for late Miocene environmental change in this part of the southern hemisphere. This suggests that mountain building over time fundamentally controlled habitat evolution along the central Andes.

  18. The Irish potato famine pathogen Phytophthora infestans originated in central Mexico rather than the Andes.

    PubMed

    Goss, Erica M; Tabima, Javier F; Cooke, David E L; Restrepo, Silvia; Fry, William E; Forbes, Gregory A; Fieland, Valerie J; Cardenas, Martha; Grünwald, Niklaus J

    2014-06-17

    Phytophthora infestans is a destructive plant pathogen best known for causing the disease that triggered the Irish potato famine and remains the most costly potato pathogen to manage worldwide. Identification of P. infestan's elusive center of origin is critical to understanding the mechanisms of repeated global emergence of this pathogen. There are two competing theories, placing the origin in either South America or in central Mexico, both of which are centers of diversity of Solanum host plants. To test these competing hypotheses, we conducted detailed phylogeographic and approximate Bayesian computation analyses, which are suitable approaches to unraveling complex demographic histories. Our analyses used microsatellite markers and sequences of four nuclear genes sampled from populations in the Andes, Mexico, and elsewhere. To infer the ancestral state, we included the closest known relatives Phytophthora phaseoli, Phytophthora mirabilis, and Phytophthora ipomoeae, as well as the interspecific hybrid Phytophthora andina. We did not find support for an Andean origin of P. infestans; rather, the sequence data suggest a Mexican origin. Our findings support the hypothesis that populations found in the Andes are descendants of the Mexican populations and reconcile previous findings of ancestral variation in the Andes. Although centers of origin are well documented as centers of evolution and diversity for numerous crop plants, the number of plant pathogens with a known geographic origin are limited. This work has important implications for our understanding of the coevolution of hosts and pathogens, as well as the harnessing of plant disease resistance to manage late blight.

  19. Aerosol transport along the Andes from Amazonia to the remote Pacific Ocean: A multiyear CALIOP assessment

    NASA Astrophysics Data System (ADS)

    Bourgeois, Quentin; Ekman, Annica; Krejci, Radovan

    2015-04-01

    The free troposphere over South America and the Pacific Ocean is a particularly interesting region to study due to the prevailing easterly wind direction, forcing air over Amazonia towards the Pacific Ocean but encountering a natural barrier - the Andes - in between which might play a significant role. In addition, the strong contrast between the wet, relatively clean season and the dry, relatively polluted season as well as the difference between day and night meteorological conditions may influence the vertical distribution of aerosols in the free troposphere. Six years (2007-2012) of CALIOP observations at both day and night were used to investigate the vertical distribution, transport and removal processes of aerosols over South America and the Pacific Ocean. The multiyear assessment shows that aerosols, mainly biomass burning particles emitted during the dry season in Amazonia, may be lifted along the Andes. During their lifting, aerosols remain in the boundary layer which makes them subject to scavenging and deposition processes. The removal aerosol extinction rate was quantified. After reaching the top of the Andes, free tropospheric aerosols are likely pushed by the large-scale subsidence towards the marine boundary layer (MBL) during their transport over the Pacific Ocean. CALIOP observations may indicate that aerosols are transported over thousands of kilometers in the free troposphere over the Pacific Ocean. During their long range transport, aerosols could be entrained into the MBL and may further act as cloud condensation nuclei, and influence climate and the radiative budget of the Earth.

  20. Imaging the transition from flat to normal subduction: variations in the structure of the Nazca slab and upper mantle under southern Peru and northwestern Bolivia

    NASA Astrophysics Data System (ADS)

    Scire, Alissa; Zandt, George; Beck, Susan; Long, Maureen; Wagner, Lara; Minaya, Estela; Tavera, Hernando

    2016-01-01

    Two arrays of broad-band seismic stations were deployed in the north central Andes between 8° and 21°S, the CAUGHT array over the normally subducting slab in northwestern Bolivia and southern Peru, and the PULSE array over the southern part of the Peruvian flat slab where the Nazca Ridge is subducting under South America. We apply finite frequency teleseismic P- and S-wave tomography to data from these arrays to investigate the subducting Nazca plate and the surrounding mantle in this region where the subduction angle changes from flat north of 14°S to normally dipping in the south. We present new constraints on the location and geometry of the Nazca slab under southern Peru and northwestern Bolivia from 95 to 660 km depth. Our tomographic images show that the Peruvian flat slab extends further inland than previously proposed along the projection of the Nazca Ridge. Once the slab re-steepens inboard of the flat slab region, the Nazca slab dips very steeply (˜70°) from about 150 km depth to 410 km depth. Below this the slab thickens and deforms in the mantle transition zone. We tentatively propose a ridge-parallel slab tear along the north edge of the Nazca Ridge between 130 and 350 km depth based on the offset between the slab anomaly north of the ridge and the location of the re-steepened Nazca slab inboard of the flat slab region, although additional work is needed to confirm the existence of this feature. The subslab mantle directly below the inboard projection of the Nazca Ridge is characterized by a prominent low-velocity anomaly. South of the Peruvian flat slab, fast anomalies are imaged in an area confined to the Eastern Cordillera and bounded to the east by well-resolved low-velocity anomalies. These low-velocity anomalies at depths greater than 100 km suggest that thick mantle lithosphere associated with underthrusting of cratonic crust from the east is not present. In northwestern Bolivia a vertically elongated fast anomaly under the Subandean Zone

  1. Preliminary dielectric and rock magnetic results for a set of prehistoric Amerindian pottery samples from different Venezuelan Islands

    NASA Astrophysics Data System (ADS)

    Costanzo-Alvarez, V.; Suárez, N.; Aldana, M.; Hernández, M. C.; Campos, C.

    2006-10-01

    Potsherds from 7 Venezuelan islands have been studied using a two-fold magneto/dielectric technique in order to identify clay sources and characterize different stages of pottery craftsmanship. This is the first study of archeological material using this technique. Petrographic analyses appear to agree with the clusters of data identified in scatter plots of initial magnetic susceptibility versus saturation isothermal remanent magnetization (SIRM), and natural remanent magnetization (NRM). Thus, these magnetic parameters appear to be suitable for describing clay source characteristics. Effective magnetic grain sizes, investigated via stability analyses of SIRM and anystheretic remanent magnetization (ARM) upon alternating field (AF) demagnetization, and SIRM acquisition and AF demagnetization crossover plots, seem to be related to different steps of pottery craftsmanship, namely clay preparation, finishing and firing. Thermomagnetic curves might also provide valuable information about original firing conditions. A scatter plot of SIRMs intersections versus maximum current depolarization temperatures and average activation energies, shows a coarse correlation due perhaps to the fact that these rock magnetic and dielectric data are both associated to pore-related features.

  2. Transmission of Venezuelan equine encephalomyelitis virus by strains of Aedes albopictus (Diptera: Culicidae) collected in North and South America.

    PubMed

    Beaman, J R; Turell, M J

    1991-01-01

    Experimental studies were undertaken to ascertain the vector potential of North American (Houston and Alsace) and South American (Sao Paulo and Santa Teresa) strains of Aedes albopictus (Skuse) for an epizootic (Trinidad donkey) strain of Venezuelan equine encephalomyelitis (VEE) virus. Infection rates were similar in all four strains of Ae. albopictus tested after ingestion of VEE virus from a viremic hamster. Virus disseminated from the midgut to the hemocoel in about 80% of infected mosquitoes, regardless of the dose ingested (10(4.6) to 10(5.7) plaque-forming units per mosquito) or the time of extrinsic incubation (7-35 d). Although all four strains of this mosquito transmitted VEE virus by bite to hamsters, transmission rates were significantly higher for the South American strains (24%, 40 of 170) than for the North American strains (5%, 9 of 165). Although VEE virus has never been isolated from Ae. albopictus, the introduction of this species into the Americas may allow it to serve as an amplification vector in areas where epizootic strains of VEE are found or introduced.

  3. Age-specific prevalence of Escherichia coli with localized and aggregative adherence in Venezuelan infants with acute diarrhea.

    PubMed

    González, R; Díaz, C; Mariño, M; Cloralt, R; Pequeneze, M; Pérez-Schael, I

    1997-05-01

    To evaluate the epidemiological significance of HEp-2 cell-adherent Escherichia coli isolates in diarrheal disease, we performed a study with 513 Venezuelan infants with diarrhea and 241 age-matched controls to determine the prevalence of enteropathogenic E. coli (enteroadherent E. coli, enterotoxigenic E. coli, enteroinvasive E. coli, and enterohemorrhagic E. coli) and their correlation with O:H serotypes. E. coli isolates exhibiting localized and aggregative adherence in the HEp-2 cell assay were significantly more frequently isolated from the patients (8.5 and 26.9%, respectively) than from the controls (1.7 and 15%, respectively). This difference was significant for the group 0 to 2 months of age but for older infants. Regardless of age, E. coli isolates with diffuse adherence were found at similar frequencies in both the patients and the controls. A striking correlation between classic O serogroups and localized adherence was also observed. These findings confirm the pathogenic role of E. coli with localized and aggregative adherence in diarrheal disease, as well as the epidemiological importance of O:H serotyping for characterizing localized-adhering E. coli.

  4. Hydrodynamism, crude oil distribution and geochemistry of the stratigraphic column in a transect of the Eastern Venezuelan Basin

    SciTech Connect

    Gallango, O.; Escandon, M.; Alberdi, M. ); Parnaud, F.; Pascual, J.C. )

    1992-01-01

    The hydrocarbon accumulation history in a transect of the Eastern Venezuelan Basin is closely related to the generation and migration process as a consequence of the stratigraphic, structural and tectonic evolution of the basin during the Cretaceous and Cenozoic times. Thermal maturity assessment based on kinetic parameters using the appropriate software indicates that the generation of oil from the marine facies of the Querecual and San Antonio source rocks in the northern part of the basin took place during early Paleocene to early Miocene times prior to the start of thrusting, while the second and third phase occurred during middle Miocene to recent times in zones beneath the principal thrust in the Maturing area. The third phase of oil generation is associated with the latter thrusts which are out of sequence. Taking into consideration the development of the oil and gas kitchen through time, the hydrodynamism, the characteristics and distribution of the hydrocarbons, the migration of oil and gas have been outlined. The major differences observed among the oils, are due to maturity and post-accumulation processes such as oil mixing and biodegradation. A wide range of thermal maturity was observed in the oils, which is mainly due to the thermal stress experienced by the source rock. Association of light crudes with meteoric waters have been observed, as well as heavy to extra-heavy crudes with connate waters at greater depth. These unusual associations of crudes and formation waters are related to the hydrodynamical regime in the basin.

  5. Comparative pollination biology of Venezuelan columnar cacti and the role of nectar-feeding bats in their sexual reproduction.

    PubMed

    Nassar, J; Ramirez, N; Linares, O

    1997-07-01

    The floral biology, reproductive system, and visitation behavior of pollinators of four species of columnar cacti, Stenocereus griseus, Pilosocereus moritzianus, Subpilocereus repandus, and Subpilocereus horrispinus, were studied in two arid zones in the north of Venezuela. Our results support the hypothesis that Venezuelan species of columnar cacti have evolved toward specialization on bat pollination. Additional information on the floral biology of a fifth species, Pilosocereus lanuginosus, was also included. All species showed the typical traits that characterize the pollination syndrome of chiropterophily. All species but Pilosocereus moritzianus were obligate outcrossers. Nectar and pollen were restricted to nocturnal floral visitors. Two species of nectar-feeding bats, Leptonycteris curasoae Miller and Glossophaga longirostris Miller, were responsible for practically all the fruit set in these cacti. Frequency of bat visitation per flower per night was highly variable within and between species of cactus, with average frequencies varying between 27 and 78 visits/flower/night. In general terms, the pattern of floral visitation through the night was significantly correlated with the pattern of nectar production and nectar sugar concentration for all species of cactus. Under natural pollination, fruit:flower ratios varied from 0.46 in Subpilocereus repandus to 0.76 in Stenocereus griseus. The efficiency of bat pollination in terms of seed:ovule ratio was high in all species, varying between 0.70 and 0.94.

  6. High-resolution Adjoint Tomography of the Eastern Venezuelan Crust using Empirical Green's Function Waveforms from Ambient Noise Interferometry

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    We present a high-resolution 3D crustal model of Eastern Venezuela from a full waveform inversion adjoint tomography technique, based on the spectral-element method. Empirical Green's functions (EGFs) of Rayleigh waves from ambient noise interferometry serve as the observed waveforms. Rayleigh wave signals in the period range of 10 - 50 s were extracted by cross-correlations of 48 stations from both Venezuelan national seismic network and the BOLIVAR project array. The synthetic Green's functions (SGFs) are calculated with an initial regional 3D shear wave model determined from ballistic Rayleigh wave tomography from earthquake records with periods longer than 20 s. The frequency-dependent traveltime time misfits between the SGFs and EGFs are minimized iteratively using adjoint tomography = to refine 3D crustal structure [Chen et al. 2014]. The final 3D model shows lateral shear wave velocity variations that are well correlated with the geological terranes within the continental interior. In particular, the final model reveals low velocities distributed along the axis of the Espino Graben, indicating that the graben has a substantially different crustal structure than the rest of the Eastern Venezuela Basin. We also observe high shear velocities in the lower crust beneath some of the subterranes of the Proterozoic-Archean Guayana Shield.

  7. Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the Southern Andes

    USGS Publications Warehouse

    Futa, K.; Stern, C.R.

    1988-01-01

    Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46??S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54??S) range for 87Sr 86Sr from 0.70280 to 0.70591 and for 143Nd 144Nd from 0.51314 to 0.51255. The ranges are significantly greater than previously reported from the southern Andes but are different from the isotopic compositions of volcanoes in the central and northern Andes. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have 87Sr 86Sr, 143Nd 144Nd, La Yb, Ba La, and Hf Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35??S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33?? and 34??S, basaltic andesites and andesites have higher 87Sr 86Sr, Rb Cs, and Hf Lu, and lower 143Nd 144Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54??S) has Sr and Nd isotopic compositions and K Rb and Ba La similar to MORB. The high La Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO2, K2O, Rb, Ba, Ba La, and 87Sr 86Sr and decrease in MgO, Sr, K Rb, Rb Cs, and 143Nd 144Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra

  8. Late Miocene climate variability and surface elevation in the central Andes

    NASA Astrophysics Data System (ADS)

    Mulch, Andreas; Uba, Cornelius E.; Strecker, Manfred R.; Schoenberg, R.; Chamberlain, C. Page

    2010-02-01

    Temporal and spatial variations in topography and oxygen stable isotope ratios in precipitation in the central Andes have stimulated widespread discussion about the competing roles of mantle and crustal processes and their feedbacks with global-scale climatic change in uplifting and shaping the central Andes. In general, one of the major obstacles in assessing the relative contributions of long-term (10 5-10 6a) tectonic processes and precipitation (as a proxy for climate) to the uplift history of the Andean orogen is the lack of integrated data sets that record late Miocene patterns of uplift and climate. Radiogenic ( 87Sr/ 86Sr), sedimentologic, and stable isotope ( δ18O) data from Subandean foreland deposits of the Chaco Basin (Bolivia) show a rapid (< 200 ka) transition towards higher δ18O and 87Sr/ 86Sr values at ˜ 8.5 Ma that we interpret to reflect a change in precipitation patterns along the Eastern Cordillera and the Subandean fold-thrust belt. In agreement with δ13C studies on paleosol carbonates we attribute this change to a southward deflection of the South American low-level jet (LLJ) that currently exerts the dominant control over the seasonality and amount of precipitation along the Eastern flanks of the Andes. Deflection of the LLJ occurred most likely as the combined effects of readjustment of relief and topography within the Eastern Cordillera at 20-22°S and possibly associated surface uplift of the Altiplano. Contemporaneous rapid positive shifts in δ18O and 87Sr/ 86Sr of pedogenic carbonate in fluvial foreland deposits are consistent with a transition to more seasonal precipitation conditions and critical threshold elevations being attained that affected South American atmospheric circulation patterns. A four-fold increase in sedimentation rates in the foreland together with a shift to strongly radiogenic 87Sr/ 86Sr ratios in paleo-river water and sediment load as well as river incision into the well preserved San Juán del Oro paleo

  9. Developing services for climate impact and adaptation baseline information and methodologies for the Andes

    NASA Astrophysics Data System (ADS)

    Huggel, C.

    2012-04-01

    Impacts of climate change are observed and projected across a range of ecosystems and economic sectors, and mountain regions thereby rank among the hotspots of climate change. The Andes are considered particularly vulnerable to climate change, not only due to fragile ecosystems but also due to the high vulnerability of the population. Natural resources such as water systems play a critical role and are observed and projected to be seriously affected. Adaptation to climate change impacts is therefore crucial to contain the negative effects on the population. Adaptation projects require information on the climate and affected socio-environmental systems. There is, however, generally a lack of methodological guidelines how to generate the necessary scientific information and how to communicate to implementing governmental and non-governmental institutions. This is particularly important in view of the international funds for adaptation such as the Green Climate Fund established and set into process at the UNFCCC Conferences of the Parties in Cancun 2010 and Durban 2011. To facilitate this process international and regional organizations (World Bank and Andean Community) and a consortium of research institutions have joined forces to develop and define comprehensive methodologies for baseline and climate change impact assessments for the Andes, with an application potential to other mountain regions (AndesPlus project). Considered are the climatological baseline of a region, and the assessment of trends based on ground meteorological stations, reanalysis data, and satellite information. A challenge is the scarcity of climate information in the Andes, and the complex climatology of the mountain terrain. A climate data platform has been developed for the southern Peruvian Andes and is a key element for climate data service and exchange. Water resources are among the key livelihood components for the Andean population, and local and national economy, in particular for

  10. Geology of the lower Yellow Creek Area, Northwestern Colorado

    SciTech Connect

    Hail, W.J.

    1990-01-01

    The lower Yellow Creek area is located in Rio Blanco and Moffat Counties of northwestern Colorado, about midway between the towns of Rangely and Meeker. The study area is in the northwestern part of the Piceance Creek basin, a very deep structural and sedimentary basin that formed during the Laramide orogeny. Potentially important resources in the area are oil shale and related minerals, oil and gas, coal, and uranium. Topics discussed in the report include: Stratigraphy (Subsurface rocks, Cretaceous rocks, Tertiary rocks, and Quaternary deposits); Structure (Midland anticline, graben at Pinyon Ridge, and Crooked Wash syncline, Folds and faults in the vicinity of the White River, Red Wash syncline and central graben zone, Yellow Creek anticlinal nose); Economic geology (Oil shale and associated minerals, Coal, Oil and gas, Uranium, Gravel).

  11. Seroprevalence of trichinellosis in domestic animals in northwestern Vietnam.

    PubMed

    Thi, N Vu; De, N V; Praet, N; Claes, L; Gabriël, S; Dorny, P

    2013-03-31

    Trichinellosis is an important emerging or re-emerging zoonotic disease in Southeast Asia. In Vietnam, data on trichinellosis are scarce. Therefore, the present study was designed to determine the seroprevalence of trichinellosis in the domestic lifecycle in two provinces of northwestern Vietnam, where recently isolated outbreaks of human trichinellosis occurred. Serum samples were obtained from 558 pigs, 125 dogs and 98 cats, transported on filter paper, and tested for Trichinella antibodies by ELISA and Western blot, using larval excretory-secretory (E/S) antigens. The overall seroprevalence of antibodies to Trichinella was 5.6%, 4% and 0% in pigs, dogs and cats, respectively. In pigs, positive cases were distributed in 8/20 districts of the two provinces. This study suggests that Trichinella spp. is circulating in the domestic life cycle in northwestern Vietnam. Further study is recommended to investigate the presence of Trichinella in a sylvatic cycle, and to identify the occurring Trichinella species.

  12. Geological mapping in northwestern Saudi Arabia using LANDSAT multispectral techniques

    NASA Technical Reports Server (NTRS)

    Blodget, H. W.; Brown, G. F.; Moik, J. G.

    1975-01-01

    Various computer enhancement and data extraction systems using LANDSAT data were assessed and used to complement a continuing geologic mapping program. Interactive digital classification techniques using both the parallel-piped and maximum-likelihood statistical approaches achieve very limited success in areas of highly dissected terrain. Computer enhanced imagery developed by color compositing stretched MSS ratio data was constructed for a test site in northwestern Saudi Arabia. Initial results indicate that several igneous and sedimentary rock types can be discriminated.

  13. Northwestern University Facility for Clean Catalytic Process Research

    SciTech Connect

    Marks, Tobin Jay

    2013-05-08

    Northwestern University with DOE support created a Facility for Clean Catalytic Process Research. This facility is designed to further strengthen our already strong catalysis research capabilities and thus to address these National challenges. Thus, state-of-the art instrumentation and experimentation facility was commissioned to add far greater breadth, depth, and throughput to our ability to invent, test, and understand catalysts and catalytic processes, hence to improve them via knowledge-based design and evaluation approaches.

  14. Food habits of pumas in northwestern Sonora, Mexico

    USGS Publications Warehouse

    Rosas-Rosas, O. C.; Valdez, R.; Bender, L.C.; Daniel, D.

    2003-01-01

    It is questionable whether food-habits studies of pumas conducted in the southwestern United States can be extrapolated to northwestern Mexico, because of differences in management, distribution, and abundance of wildlife. We determined food habits of pumas (Puma concolor) in the Sonoran Desert of northwestern Sonora, Mexico. Based on studies in the western United States, we hypothesized that desert mule deer (Odocoileus hemionus) were the major food source of pumas in Sonoran Desert habitats of Mexico. The study area supports populations of desert mule deer, white-tailed deer (Odocoileus virginianus), lagomorphs (Lepus spp. and Sylvilagus audubonii), collared peccary (Pecari tajacu), and the largest population (???300 individuals) of desert bighorn sheep (Ovis canadensis) in Sonora. Based on pugmark characteristics, we recorded 3 different adult resident pumas in approximately 90 km2. We analyzed 60 puma fecal samples collected September 1996-November 1998. Primary prey items based on frequency of occurrence and estimated biomass consumed were desert bighorn sheep (40% and 45%, respectively), lagomorphs (33%, 19%), deer (17%, 17%), and collared peccary (15%, 11%). The high percentage of desert bighorn sheep in puma diets may be due to high abundance relative to mule deer, which declined in number during our study. No differences were found in puma diets between seasons (??22=2.4526, P=0.2934). Fluctuations in mule deer populations in northwestern Sonora may influence prey selection by pumas.

  15. Out of Amazonia again and again: episodic crossing of the Andes promotes diversification in a lowland forest flycatcher

    PubMed Central

    Miller, Matthew J; Bermingham, Eldredge; Klicka, John; Escalante, Patricia; do Amaral, Fabio S. Raposo; Weir, Jason T; Winker, Kevin

    2008-01-01

    Most Neotropical lowland forest taxa occur exclusively on one side of the Andes despite the availability of appropriate habitat on both sides. Almost all molecular phylogenies and phylogenetic analyses of species assemblages (i.e. area cladograms) have supported the hypothesis that Andean uplift during the Late Pliocene created a vicariant barrier affecting lowland lineages in the region. However, a few widespread plant and animal species occurring in lowland forests on both sides of the Andes challenge the generality of this hypothesis. To understand the role of the Andes in the history of such organisms, we reconstructed the phylogeographic history of a widespread Neotropical flycatcher (Mionectes oleagineus) in the context of the other four species in the genus. A molecular phylogeny based on nuclear and mitochondrial sequences unambiguously showed an early basal split between montane and lowland Mionectes. The phylogeographic reconstruction of lowland taxa revealed a complex history, with multiple cases in which geographically proximate populations do not represent sister lineages. Specifically, three populations of M. oleagineus west of the Andes do not comprise a monophyletic clade; instead, each represents an independent lineage with origins east of the Andes. Divergence time estimates suggest that at least two cross-Andean dispersal events post-date Andean uplift. PMID:18285279

  16. A phylogenetic analysis using full-length viral genomes of South American dengue serotype 3 in consecutive Venezuelan outbreaks reveals novel NS5 mutation

    PubMed Central

    Schmidt, DJ; Pickett, BE; Camacho, D; Comach, G; Xhaja, K; Lennon, NJ; Rizzolo, K; de Bosch, N; Becerra, A; Nogueira, ML; Mondini, A; da Silva, EV; Vasconcelos, PF; Muñoz-Jordán, JL; Santiago, GA; Ocazionez, R; Gehrke, L; Lefkowitz, EJ; Birren, BW; Henn, MR; Bosch, I

    2013-01-01

    Dengue virus currently causes 50-100 million infections annually. Comprehensive knowledge about the evolution of Dengue in response to selection pressure is currently unavailable, but would greatly enhance vaccine design efforts. In the current study, we sequenced 187 new dengue virus serotype 3(DENV-3) genotype III whole genomes isolated from Asia and the Americas. We analyzed them together with previously-sequenced isolates to gain a more detailed understanding of the evolutionary adaptations existing in this prevalent American serotype. In order to analyze the phylogenetic dynamics of DENV-3 during outbreak periods; we incorporated datasets of 48 and 11 sequences spanning two major outbreaks in Venezuela during 2001 and 2007-2008 respectively. Our phylogenetic analysis of newly sequenced viruses shows that subsets of genomes cluster primarily by geographic location, and secondarily by time of virus isolation. DENV-3 genotype III sequences from Asia are significantly divergent from those from the Americas due to their geographical separation and subsequent speciation. We measured amino acid variation for the E protein by calculating the Shannon entropy at each position between Asian and American genomes. We found a cluster of 7 amino acid substitutions having high variability within E protein domain III, which has previously been implicated in serotype-specific neutralization escape mutants. No novel mutations were found in the E protein of sequences isolated during either Venezuelan outbreak. Shannon entropy analysis of the NS5 polymerase mature protein revealed that a G374E mutation, in a region that contributes to interferon resistance in other flaviviruses by interfering with JAK-STAT signaling was present in both the Asian and American sequences from the 2007-2008 Venezuelan outbreak, but was absent in the sequences from the 2001 Venezuelan outbreak. In addition to E, several NS5 amino acid changes were unique to the 2007-2008 epidemic in Venezuela and may

  17. Late paleozoic tectonic amalgamation of northwestern China. Sedimentary record of the northern Tarim, northwestern Turpan, and southern Junggar basins

    SciTech Connect

    Carroll, A.R.; Graham, S.A.; Hendrix, M.S.; Ying, D.; Zhou, D.

    1995-05-01

    This study focuses on areas adjacent to the Tian Shan (shan is Chinese for mountains) in Xinjiang Uygur Autonomous Region, northwestern China, and provides new field data on Carboniferous and Permian outcrop exposures of sedimentary rocks of the southern Junggar, northwestern Turpan, and northern Tarim basins that bear directly on the history of late Paleozoic tectonic amalgamation. We present here a multifaceted sedimentary basin analysis, including sedimentary facies, paleocurrent, and sandstone provenance analyses, and reconstructions of late Paleozoic basin subsidence. These data provide a unique record not only of the basins themselves, but also of the evolution of the adjacent orogenic belts. This study is based on fieldwork during the summers of 1987, 1988, 1991, and 1992 by workers from Stanford University, the Chinese Academy of Geological Sciences, and the Xinjiang Bureau of Geology and Mineral Resources. Although reconnaissance in nature, the data presented here provide a basis for evaluating alternative hypotheses for the evolution of northwestern China and provide a starting point for more comprehensive future studies. 72 refs., 18 figs., 1 tab.

  18. 75 FR 53687 - Southern Montana Electric Generation & Transmission Cooperative, Inc. v. NorthWestern Corporation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-01

    ...] Southern Montana Electric Generation & Transmission Cooperative, Inc. v. NorthWestern Corporation; Notice...) Rules of Practice and Procedure, 18 CFR 385.206, Southern Montana Electric Generation &...

  19. A new species of Alopoglossus lizard (Squamata, Gymnophthalmidae) from the tropical Andes, with a molecular phylogeny of the genus.

    PubMed

    Torres-Carvajal, Omar; Lobos, Simón E

    2014-01-01

    We describe a new species of Alopoglossus from the Pacific slopes of the Andes in northern Ecuador based on morphological and molecular evidence. The new species differs most significantly from all other congeners in having a double longitudinal row of widened gular scales, lanceolate dorsal scales in transverse rows, 29-32 dorsal scales in a transverse row at midbody, and 4 longitudinal rows of ventrals at midbody. It is most similar in morphology to A. festae, the only species of Alopoglossus currently recognized in western Ecuador. We analyze the phylogenetic relationships among species of Alopoglossus based on the mitochondrial gene ND4. Cis-Andean [east of the Andes] and Trans-Andean [west of the Andes] species are nested in two separate clades, suggesting that the uplift of these mountains had an important effect in the diversification of Alopoglossus. In addition, we present an updated key to the species of Alopoglossus.

  20. Deformation of the central Andes (15-27 deg S) derived from a flow model of subduction zones

    NASA Technical Reports Server (NTRS)

    Wdowinski, Shimon; O'Connell, Richard J.

    1991-01-01

    A simple viscous flow model of a subduction zone is used to calculate the deformation within continental lithosphere above a subducting slab. This formulation accounts for two forces that dominate the deformation in the overriding lithosphere: tectonic forces and buoyancy forces. Numerical solutions, obtained by using a finite element technique, are compared with observations from the central Andes (15-27 deg S). The model predicts the observed deformation pattern of extension in the forearc, compression in the Western Monocline (corresponding to magmatic activity), extension in the Altiplano, compression in the Eastern Monocline and Subandes, and no deformation in the Brazilian Shield. By comparing the calculated solutions with the large-scale tectonic observations, the forces that govern the deformation in the central Andes are evaluated. The approximately constant subduction velocity in the past 26 million years suggests that the rate of crustal shortening in the Andes has decreased with time due to the thickening of the crust.

  1. Surface control on contrasts in deformation between eastern and western margins of the Central Andes

    NASA Astrophysics Data System (ADS)

    Schlunegger, F.; Norton, K. P.

    2012-04-01

    The deformation style and climate between the eastern and western escarpments of the Central Andes are strikingly different. The eastern side is in a tropical climate; it receives annual precipitation amounts of >3500 mm and experiences active shortening and thrusting, while the western side is one of the driest places on Earth and is deformed by long-wavelength warping. Indeed, climate is so dry that the western slopes can go decades without recorded rainfall. Here we show that the modern distribution of deformation in the Central Andes can be a result of enhanced orographic precipitation pattern beginning ca. 7-10 Ma (Norton and Schlunegger, 2011). Reduced erosion on the western side would have steepened the orogen, forcing deformation to shift to the east where high precipitation amounts would have enhanced erosion. We support this hypothesis with low erosion rates and a well-defined retreating knickzone in the Western Andes, and likewise by high erosion rates and channel morphologies indicative of transient orographic feedbacks in the east. Indeed, erosion rates as measured by cosmogenic nuclides are < 0.01 mm yr-1 in the west (Kober et al., 2007) and more than an order of magnitude higher, > 0.2 mm yr-1, in the east (Safran et al. 2005). Stream profiles from the Western Escarpment are indicative of slow knickzone retreat in the absence of modern tectonic forcing while streams on the Eastern Escarpment are the product of strong climate-tectonic feedbacks, indicated by steep and strongly concave segments in the orographically-affected reach. Reconstructions of the accretionary wedge geometry and high angle fault movements between the Miocene and today further support an erosion driven shift in the locus of deformation. In particular, at orogenic scales, critical taper calculations indicate that the near cessation of erosion on the western side ca. 7-10 Ma ago shifted the orogen into a super-critical state where deformation only occurs along the basal d

  2. Replication and clearance of Venezuelan equine encephalitis virus from the brains of animals vaccinated with chimeric SIN/VEE viruses.

    PubMed

    Paessler, Slobodan; Ni, Haolin; Petrakova, Olga; Fayzulin, Rafik Z; Yun, Nadezhda; Anishchenko, Michael; Weaver, Scott C; Frolov, Ilya

    2006-03-01

    Venezuelan equine encephalitis virus (VEEV) is an important, naturally emerging zoonotic pathogen. Recent outbreaks in Venezuela and Colombia in 1995, involving an estimated 100,000 human cases, indicate that VEEV still poses a serious public health threat. To develop a safe, efficient vaccine that protects against disease resulting from VEEV infection, we generated chimeric Sindbis (SIN) viruses expressing structural proteins of different strains of VEEV and analyzed their replication in vitro and in vivo, as well as the characteristics of the induced immune responses. None of the chimeric SIN/VEE viruses caused any detectable disease in adult mice after either intracerebral (i.c.) or subcutaneous (s.c.) inoculation, and all chimeras were more attenuated than the vaccine strain, VEEV TC83, in 6-day-old mice after i.c. infection. All vaccinated mice were protected against lethal encephalitis following i.c., s.c., or intranasal (i.n.) challenge with the virulent VEEV ZPC738 strain (ZPC738). In spite of the absence of clinical encephalitis in vaccinated mice challenged with ZPC738 via i.n. or i.c. route, we regularly detected high levels of infectious challenge virus in the central nervous system (CNS). However, infectious virus was undetectable in the brains of all immunized animals at 28 days after challenge. Hamsters vaccinated with chimeric SIN/VEE viruses were also protected against s.c. challenge with ZPC738. Taken together, our findings suggest that these chimeric SIN/VEE viruses are safe and efficacious in adult mice and hamsters and are potentially useful as VEEV vaccines. In addition, immunized animals provide a useful model for studying the mechanisms of the anti-VEEV neuroinflammatory response, leading to the reduction of viral titers in the CNS and survival of animals.

  3. Glycoproteins E2 of the Venezuelan and eastern equine encephalomyelitis viruses contain multiple cross-reactive epitopes.

    PubMed

    Pereboev, A V; Razumov, I A; Svyatchenko, V A; Loktev, V B

    1996-01-01

    Enzyme immunoassay (EIA) with sixty types of monoclonal antibodies (MAbs) was used to study cross-reactive epitopes on the attenuated and virulent strains of the Eastern equine encephalomyelitis (EEE) and Venezuelan equine encephalomyelitis (VEE) viruses. All three structural proteins of the EEE and VEE viruses were demonstrated to have both cross-reactive and specific antigenic determinants. The glycoprotein E1 of EEE and VEE viruses possesses three cross-reactive epitopes for binding to MAbs. The glycoprotein E2 has a cluster of epitopes for 20 cross-reacting MAbs produced to EEE and VEE viruses. Cross-reactive epitopes were localised within five different sites of glycoprotein E2 of VEE virus and within four sites of that of the EEE virus. There are no cross-neutralising MAbs to the VEE and EEE viruses. Only one type of the protective Mabs was able to cross-protect mice against lethal infection by the virulent strains of the VEE and EEE viruses. Eight MAbs blocked the hemagglutination activity (HA) of both viruses. Antigenic alterations of neutralising and protective sites were revealed for all attenuated strains of the VEE and EEE viruses. Comparative studies of the E2 proteins amino acid sequences show that the antigenic modifications observed with the attenuated strains of the VEE virus may be caused by multiple amino acid changes in positions 7, 62, 120, 192 and 209-213. The escape-variants of the VEE virus obtained with cross-reactive MAbs 7D1, 2D4 and 7A6 have mutations of the E2 protein at positions 59, 212-213 and 232, respectively. Amino acid sequences in these regions of the VEE and EEE viruses are not homologous. These observations indicate that cross-reactive MAbs are capable of recognising discontinuous epitopes on the E2 glycoprotein.

  4. Repeated emergence of epidemic/epizootic Venezuelan equine encephalitis from a single genotype of enzootic subtype ID virus.

    PubMed Central

    Powers, A M; Oberste, M S; Brault, A C; Rico-Hesse, R; Schmura, S M; Smith, J F; Kang, W; Sweeney, W P; Weaver, S C

    1997-01-01

    Venezuelan equine encephalitis (VEE) epidemics and equine epizootics occurred periodically in the Americas from the 1920s until the early 1970s, when the causative viruses, subtypes IAB and IC, were postulated to have become extinct. Recent outbreaks in Columbia and Venezuela have renewed interest in the source of epidemic/epizootic viruses and their mechanism of interepizootic maintenance. We performed phylogenetic analyses of VEE virus isolates spanning the entire temporal and geographic range of strains available, using 857-nucleotide reverse transcription-PCR products including the E3 and E2 genes. Analyses indicated that epidemic/epizootic viruses are closely related to four distinct, enzootic subtype ID-like lineages. One of these lineages, which occurs in Columbia, Peru, and Venezuela, also included all of the epidemic/epizootic isolates; the remaining three ID-like lineages, which occur in Panama, Peru, Florida, coastal Ecuador, and southwestern Columbia, were apparently not associated with epizootic VEE emergence. Within the Columbia/Peru/Venezuela lineage, three distinct monophyletic groups of epidemic/epizootic viruses were delineated, indicating that VEE emergence has occurred independently at least three times (convergent evolution). Representative, complete E2 amino acid sequences were compared to identify potential determinants of equine virulence and epizootic emergence. Amino acids implicated previously in laboratory mouse attenuation generally did not vary among the natural isolates that we examined, indicating that they probably are not involved in equine virulence changes associated with VEE emergence. Most informative amino acids correlated with phylogenetic relationships rather than phenotypic characteristics, suggesting that VEE emergence has resulted from several distinct combinations of mutations that generate viruses with similar antigenic and equine virulence phenotypes. PMID:9261393

  5. Development of human antibody fragments using antibody phage display for the detection and diagnosis of Venezuelan equine encephalitis virus (VEEV)

    PubMed Central

    Kirsch, Martina Inga; Hülseweh, Birgit; Nacke, Christoph; Rülker, Torsten; Schirrmann, Thomas; Marschall, Hans-Jürgen; Hust, Michael; Dübel, Stefan

    2008-01-01

    Background Venezuelan equine encephalitis virus (VEEV) belongs to the Alphavirus group. Several species of this family are also pathogenic to humans and are recognized as potential agents of biological warfare and terrorism. The objective of this work was the generation of recombinant antibodies for the detection of VEEV after a potential bioterrorism assault or an natural outbreak of VEEV. Results In this work, human anti-VEEV single chain Fragments variable (scFv) were isolated for the first time from a human naïve antibody gene library using optimized selection processes. In total eleven different scFvs were identified and their immunological specificity was assessed. The specific detection of the VEEV strains TC83, H12/93 and 230 by the selected antibody fragments was proved. Active as well as formalin inactivated virus particles were recognized by the selected antibody fragments which could be also used for Western blot analysis of VEEV proteins and immunohistochemistry of VEEV infected cells. The anti-VEEV scFv phage clones did not show any cross-reactivity with Alphavirus species of the Western equine encephalitis virus (WEEV) and Eastern equine encephalitis virus (EEEV) antigenic complex, nor did they react with Chikungunya virus (CHIKV), if they were used as detection reagent. Conclusion For the first time, this study describes the selection of antibodies against a human pathogenic virus from a human naïve scFv antibody gene library using complete, active virus particles as antigen. The broad and sensitive applicability of scFv-presenting phage for the immunological detection and diagnosis of Alphavirus species was demonstrated. The selected antibody fragments will improve the fast identification of VEEV in case of a biological warfare or terroristic attack or a natural outbreak. PMID:18764933

  6. Human transcriptome response to immunization with live-attenuated Venezuelan equine encephalitis virus vaccine (TC-83): Analysis of whole blood

    PubMed Central

    Erwin-Cohen, Rebecca A.; Porter, Aimee I.; Pittman, Phillip R.; Rossi, Cynthia A.; DaSilva, Luis

    2017-01-01

    ABSTRACT Venezuelan equine encephalitis virus (VEEV) is an important human and animal alphavirus pathogen transmitted by mosquitoes. The virus is endemic in Central and South America, but has also caused equine outbreaks in southwestern areas of the United States. In an effort to better understand the molecular mechanisms of the development of immunity to this important pathogen, we performed transcriptional analysis from whole, unfractionated human blood of patients who had been immunized with the live-attenuated vaccine strain of VEEV, TC-83. We compared changes in the transcriptome between naïve individuals who were mock vaccinated with saline to responses of individuals who received TC-83. Significant transcriptional changes were noted at days 2, 7, and 14 following vaccination. The top canonical pathways revealed at early and intermediate time points (days 2 and 7) included the involvement of the classic interferon response, interferon-response factors, activation of pattern recognition receptors, and engagement of the inflammasome. By day 14, the top canonical pathways included oxidative phosphorylation, the protein ubiquitination pathway, natural killer cell signaling, and B-cell development. Biomarkers were identified that differentiate between vaccinees and control subjects, at early, intermediate, and late stages of the development of immunity as well as markers which were common to all 3 stages following vaccination but distinct from the sham-vaccinated control subjects. The study represents a novel examination of molecular processes that lead to the development of immunity against VEEV in humans and which may be of value as diagnostic targets, to enhance modern vaccine design, or molecular correlates of protection. PMID:27870591

  7. Fore-arc structure, plate coupling and isostasy in the Central Andes: Insight from gravity data modelling

    NASA Astrophysics Data System (ADS)

    Rutledge, Sophia; Mahatsente, Rezene

    2017-02-01

    The central segment of the Peru-Chile subduction zone has not seen a major earthquake of similar scale to the megathrust Iquique event in 1877 (Magnitude ∼8.8). The plate interface between the subducting and overriding plates in the central segment of the subduction zone is highly coupled and is accumulating elastic energy. Here, we assessed the locking mechanism and isostatic state of the Central Andes based on gravity models of the crust and upper mantle structure. The density models are based on satellite gravity data and are constrained by velocity models and earthquake hypocenters. The gravity models indicate a high density batholithic structure in the fore-arc, overlying the subducting Nazca plate. This high density crustal structure is pressing downward into the slab and locking the plate interface. Thus, plate coupling in the Central Andes may result from pressure exerted by high density fore-arc structures and buoyancy force on the subducting Nazca plate. The increased compressive stress closer to the trench, due to the increased contact between the subducting and overriding plates, may increase the intraplate coupling in the Central Andes. To assess the isostatic state of the Central Andes, we determined the residual topography of the region (difference between observed and isostatic topography). There is a residual topography of ∼800 m in the western part of the Central Andes that cannot be explained by the observed crustal thicknesses. The residual topography may be attributed to mantle wedge flow and subduction of the Nazca plate. Thus, part of the observed topography in the western part of the Central Andes may be dynamically supported by mantle wedge flow below the overriding plate.

  8. Climate Change Driven Implications on Spatial Distribution of High Andean Peatlands in the Central Andes

    NASA Astrophysics Data System (ADS)

    Otto, Marco; Gibbons, Richard E.

    2013-04-01

    High Andean peatlands are among the most unique habitats in the tropical Andes and certainly among the least studied. High Andean peatlands occur patchily in montane grassland and scrub below snow line and above tree line. These high-elevation peatlands are sustained by glacial runoff and seasonal precipitation. We used remote sensing data to estimate that peatland habitat is approximately 2.5 % of our study region in the Puna, an ecoregion located in the high Andes above 4000 m a.s.l. Individual sizes of our estimated peatland polygons ranged from 0.72 ha to 1079 ha with a mean size of 4.9 ha. Climate change driven implications on spatial distribution of high Andean peatlands were assessed in two ways. First, we estimated the effect of predicted regional temperature increase by using the standard lapse rate of 2° C per 300 m for assessing peatland habitat patches that would remain above a critical thermocline. Nearly 80% of peatland habitat patches were predicted to occur below the thermocline if the prediction of 4° C temperature increase is realized. The second assessment relied on the quantified assumption that permanent snow or glacier cover, topographic characteristics (e.g. slope) and precipitation of a basin are essential variables in the occurrence of high Andean peatlands. All 17 basins were predicted to have a decrease in peatland habitat due to snow line uplift, decrease in precipitation and consequent insufficient wetland inflows. Total habitat loss was predicted for two basins in the semi-arid part of the study area with a snow line uplift to 5600 m and a projected decrease in precipitation of 1 mm per year over the next 40 years. A combined result of both assessments provides important information on climate change driven implications on the hydrology of high Andean peatlands and potential consequences for their spatial distribution within the Central Andes.

  9. Generation of the relationship between glacier area and volume for a tropical glacier in Bolivian Andes

    NASA Astrophysics Data System (ADS)

    Liu, T.; Kinouchi, T.; Hasegawa, A.; Tsuda, M.; Iwami, Y.; Asaoka, Y.; Mendoza, J.

    2015-12-01

    In Andes, retreat of tropical glaciers is rapid, thus water resources currently available from glacierized catchments would be changed in its volume and temporal variations due to climate change and glacier shrinkage. The relationship between glacier area and volume is difficult to define however which is important to monitor glaciers especially those are remote or inaccessible. Water resources in La Paz and El Alto in Bolivia, strongly depend on the runoff from glacierized headwater catchments in the Cordillera Real, Andes, which is therefore selected as our study region.To predict annual glacier mass balances, PWRI-Distributed Hydrological Model (PWRI-DHM) was applied to simulate runoff from the partially glacierized catchments in high mountains (i.e. Condoriri-Huayna West headwater catchment located in the Cordillera Real, Bolivian Andes). PWRI-DHM is based on tank model concept in a distributed and 4-tank configuration including surface, unsaturated, aquifer, and river course tanks. The model was calibrated and validated with observed meteorological and hydrological data from 2011 to 2014 by considering different phases of precipitation, various runoff components from glacierized and non-glacierized areas, and the retarding effect by glacial lakes and wetlands. The model is then applied with MRI-AGCM outputs from 1987 to 2003 considering the shrinkage of glacier outlines since 1980s derived from Landsat data. Annual glacier mass balance in each 100m-grid was reproduced, with which the glacier area-volume relationship was generated with reasonable initial volume setting. Out study established a method to define the relationship between glacier area and volume by remote sensing information and glacier mass balances simulated by distributed hydrological model. Our results demonstrated that the changing trend of local glacier had a consistency the previous observed glacier area-volume relationship in the Cordillera Real.

  10. Setting practical conservation priorities for birds in the Western Andes of Colombia.

    PubMed

    Ocampo-Peñuela, Natalia; Pimm, Stuart L

    2014-10-01

    We aspired to set conservation priorities in ways that lead to direct conservation actions. Very large-scale strategic mapping leads to familiar conservation priorities exemplified by biodiversity hotspots. In contrast, tactical conservation actions unfold on much smaller geographical extents and they need to reflect the habitat loss and fragmentation that have sharply restricted where species now live. Our aspirations for direct, practical actions were demanding. First, we identified the global, strategic conservation priorities and then downscaled to practical local actions within the selected priorities. In doing this, we recognized the limitations of incomplete information. We started such a process in Colombia and used the results presented here to implement reforestation of degraded land to prevent the isolation of a large area of cloud forest. We used existing range maps of 171 bird species to identify priority conservation areas that would conserve the greatest number of species at risk in Colombia. By at risk species, we mean those that are endemic and have small ranges. The Western Andes had the highest concentrations of such species-100 in total-but the lowest densities of national parks. We then adjusted the priorities for this region by refining these species ranges by selecting only areas of suitable elevation and remaining habitat. The estimated ranges of these species shrank by 18-100% after accounting for habitat and suitable elevation. Setting conservation priorities on the basis of currently available range maps excluded priority areas in the Western Andes and, by extension, likely elsewhere and for other taxa. By incorporating detailed maps of remaining natural habitats, we made practical recommendations for conservation actions. One recommendation was to restore forest connections to a patch of cloud forest about to become isolated from the main Andes.

  11. On Restoring Sedimentary Basins for Post-Depositional Deformation - Paleozoic Basins of the Central Andes

    NASA Astrophysics Data System (ADS)

    Bahlburg, H.

    2015-12-01

    The reconstruction and interpretation of sedimentary basins incorporated into folded and thrusted mountain belts is strongly limited by the style and intensity of shortening. This problem is exacerbated if deformation is polyphasic as is the case for the Paleozoic basins in the central Andes. Some of these have been deformed by folding and thrusting during at least 3 events in the Late Ordovician, the Late Paleozoic and Cenozoic. A realistic reconstruction of the original basin dimensions and geometries from outcrops and maps appears to be almost impossible. We present results of a stepwise reconstruction of the Paleozoic basins of the central Andes by restoring basin areas and fills accounting for crustal shortening. The structurally most prominent feature of the central Andes is the Bolivian Orocline which accomodated shortening in the last 45 Ma on the order of between 300 and 500 km. In a first step basins were restored by accounting for Cenozoic rotation and shortening by deconvolving the basins using an enhanced version of the oroclinal bending model of Ariagada et al. (2008). Results were then restored stepwise for older deformation. Constraints on these subsequent steps are significantly poorer as values of shortening can be derived only from folds and thusts apparent in outcrops. The amount of shortening accomodated on unexposed and therefore unknown thrusts can not be quantified and is a significant source of error very likely leading to an underestimation of the amount of shortening. Accepting these limitations, basin restoration results in an increase in basin area by ≥100%. The volumes of stratigraphically controlled basin fills can now be redistributed over the wider, restored area, translating into smaller rates of accumulation and hence required subsidence. The restored rates conform to those of equivalent modern basin settings and permit a more realistic and actualistic analysis of subsidence drivers and the respective tectonic framework.

  12. The Glacier Inventory of the Central Andes of Argentina (31°-35°S)

    NASA Astrophysics Data System (ADS)

    Ferri Hidalgo, L.; Zalazar, L.; Castro, M.; Pitte, P.; Masiokas, M. H.; Ruiz, L.; Villalba, R.; Delgado, S.; Gimenez, M.; Gargantini, H.

    2015-12-01

    The National Law for protection of glaciers in Argentina envisages the development of a National Inventory of Glaciers. All glaciers and periglacial landforms which are important as strategic water resource must be properly identified and mapped. Here we present a detailed and complete glacier and rock glacier inventory of the Central Andes of Argentina between 31° and 35°S. This semi-arid region contains some of the highest mountains of South America and concentrates the second most glacierized area in Argentina after the Patagonian Andes. To develop the inventory, we used remotely sensed data and related techniques complemented with field surveys. Clean ice and perennial snowfields were identified applying an automatic extraction method on medium spatial-resolution images. Debris-covered and rock glaciers were manually digitized on higher spatial-resolution images. With minor modifications, the present digital inventory is consistent with GLIMS standards. For each glacier, we derived 38 database fields, adding five specific attributes for rock glaciers, which are not included in the original GLIMS database. In total we identified 8069 glaciers covering an area of 1768 km2. Debris-covered ice and rock glaciers represent 57% of the total inventoried area. In this region, rock glaciers are a common feature in the arid landscape and constitute an important water reserve at regional scale. Many glaciers were characterized by gradual transition from debris-covered glaciers, in the upper part, to rock glaciers, in the lower sector. The remaining 43% includes clean ice glaciers and permanent snowfields. These are mostly mountain and valley-type glaciers with medium-to-small sizes. This detailed inventory constitutes a valuable contribution to the ongoing global efforts (e.g. WGI, RGI and GLIMS) to map the world's glaciers. It is also the base for ongoing glaciological, climatological and hydrological studies in this portion of southern Andes.

  13. Island radiation on a continental scale: Exceptional rates of plant diversification after uplift of the Andes

    PubMed Central

    Hughes, Colin; Eastwood, Ruth

    2006-01-01

    Species radiations provide unique insights into evolutionary processes underlying species diversification and patterns of biodiversity. To compare plant diversification over a similar time period to the recent cichlid fish radiations, which are an order of magnitude faster than documented bird, arthropod, and plant radiations, we focus on the high-altitude flora of the Andes, which is the most species-rich of any tropical mountains. Because of the recent uplift of the northern Andes, the upland environments where much of this rich endemic flora is found have been available for colonization only since the late Pliocene or Pleistocene, 2–4 million years (Myr) ago. Using DNA sequence data we identify a monophyletic group within the genus Lupinus representing 81 species endemic to the Andes. The age of this clade is estimated to be 1.18–1.76 Myr, implying a diversification rate of 2.49–3.72 species per Myr. This exceeds previous estimates for plants, providing the most spectacular example of explosive plant species diversification documented to date. Furthermore, it suggests that the high cichlid diversification rates are not unique. Lack of key innovations associated with the Andean Lupinus clade suggests that diversification was driven by ecological opportunities afforded by the emergence of island-like habitats after Andean uplift. Data from other genera indicate that lupines are one of a set of similarly rapid Andean plant radiations, continental in scale and island-like in stimulus, suggesting that the high-elevation Andean flora provides a system that rivals other groups, including cichlids, for understanding rapid species diversification. PMID:16801546

  14. Land Use Change and Hydrologic Processes in High-Elevation Tropical Watersheds of the Northern Andes

    NASA Astrophysics Data System (ADS)

    Avery, W. A.; Riveros-Iregui, D. A.; Covino, T. P.; Peña, C.

    2013-12-01

    The humid tropics cover one-fifth of the Earth's land surface and generate the greatest amount of runoff of any biome globally, but remain poorly understood and understudied. Humid tropical regions of the northern and central Andes have experienced greater anthropogenic land-use/land-cover (LULC) change than nearly any other high mountain system in the world. Vast expanses of this region are currently undergoing rapid transformation to farmland for production of potatoes and pasture for cattle grazing. Although the humid tropics have some of the highest runoff ratios, precipitation, and largest river flows in the world, there is a lack of scientific literature that addresses hydrologic processes in these regions and very few field observations are available to inform management strategies to ensure the sustainability of water resources of present and future generations. We seek to improve understanding of hydrologic processes and feedbacks in the humid tropics using existing and new information from two high-elevation watersheds that span a LULC gradient in the Andes Mountains of Colombia. One site is located in the preserved Chingaza Natural National Park in Central Colombia (undisturbed). The second site is located ~60 km to the northwest and has experienced considerable LULC change over the last 40 years. Combined, these watersheds deliver over 80% of the water resources to Bogotá and neighboring communities. These watersheds have similar climatological characteristics (including annual precipitation), but have strong differences in LULC which result in substantial differences in hydrologic response and streamflow dynamics. We present an overview of many of the pressing issues and effects that land degradation and climate change are posing to the long-term sustainability of water resources in the northern Andes. Our overarching goal is to provide process-based knowledge that will be useful to prevent, mitigate, or respond to future water crises along the Andean

  15. High Resolution Simulations of Pollution Vertical Stratification over Santiago and its Transport to the Chilean Andes

    NASA Astrophysics Data System (ADS)

    Orfanoz-Cheuquelaf, A. P.; Gallardo, L.; Huneeus, N.; Lambert, F.

    2015-12-01

    Santiago, Chile (33.5 S, 70.5 W, 500 m.a.s.l., population 7 millions) is a large city situated in a basin surrounded by the Andes in the East and smaller mountain ranges to the North, West, and South. It is plagued by abnormally high pollution levels for its size due to climatological and topological features. To date, it is unclear how far the urban pollution plume reaches up the mountain. Here we explore the region's complex atmospheric circulation and particularly the transport of black carbon (BC) using a state of the art numerical model (WRF-Chem, Weather Research and Forecasting model).Observations indicate the presence of multiple layers within the boundary layer, as well as the occurrence of uncoupled layers above the boundary layer. Here we explore mechanisms within our simulation that may explain these features. Our results suggest that they may correspond to residual layers that are produced by recirculation along mountain slopes due to the complex terrain around the city.In late August 2013, a short multi-platform measuring campaign (DIVERSOL) took place in the Santiago basin, providing the first vertical profiles of BC, accompanied by meteorological soundings. We analyze the dispersion of a quasi-passive tracer (carbon monoxide) of black carbon in our simulation to improve our understanding of the governing mixing and transport processes. We also perform sensitivity studies with respect to vertical resolution and turbulence schemes, contrasting our results against DIVERSOL data. Our simulations suggest that pollutants emitted in Santiago could reach the high regions of Andes mountains during the afternoon circulation, thus affecting local glaciers. With an entire year of simulation we find that the stratification of pollutants within the basin displays a seasonal signal, as well as a capacity to reach the Chilean Andes and affect the Andean cryosphere.

  16. Constraints on deformation of the Southern Andes since the Cretaceous from anisotropy of magnetic susceptibility

    NASA Astrophysics Data System (ADS)

    Maffione, Marco; Hernandez-Moreno, Catalina; Ghiglione, Matias C.; Speranza, Fabio; van Hinsbergen, Douwe J. J.; Lodolo, Emanuele

    2015-12-01

    The southernmost segment of the Andean Cordillera underwent a complex deformation history characterized by alternation of contractional, extensional, and strike-slip tectonics. Key elements of southern Andean deformation that remain poorly constrained, include the origin of the orogenic bend known as the Patagonian Orocline (here renamed as Patagonian Arc), and the exhumation mechanism of an upper amphibolite facies metamorphic complex currently exposed in Cordillera Darwin. Here, we present results of anisotropy of magnetic susceptibility (AMS) from 22 sites in Upper Cretaceous to upper Eocene sedimentary rocks within the internal structural domain of the Magallanes fold-and-thrust belt in Tierra del Fuego (Argentina). AMS parameters from most sites reveal a weak tectonic overprint of the original magnetic fabric, which was likely acquired upon layer-parallel shortening soon after sedimentation. Magnetic lineation from 17 sites is interpreted to have formed during compressive tectonic phases associated to a continuous N-S contraction. Our data, combined with the existing AMS database from adjacent areas, show that the Early Cretaceous-late Oligocene tectonic phases in the Southern Andes yielded continuous contraction, variable from E-W in the Patagonian Andes to N-S in the Fuegian Andes, which defined a radial strain field. A direct implication is that the exhumation of the Cordillera Darwin metamorphic complex occurred under compressive, rather than extensional or strike-slip tectonics, as alternatively proposed. If we agree with recent works considering the curved Magallanes fold-and-thrust belt as a primary arc (i.e., no relative vertical-axis rotation of the limbs occurs during its formation), then other mechanisms different from oroclinal bending should be invoked to explain the documented radial strain field. We tentatively propose a kinematic model in which reactivation of variably oriented Jurassic faults at the South American continental margin controlled

  17. Detection of 18.6 year nodal induced drought in the Patagonian Andes

    NASA Astrophysics Data System (ADS)

    Currie, Robert G.

    1983-11-01

    Analysis of tree-ring chronologies from the Patagonian Andes yields evidence for the 18.6 yr lunar nodal term in drought/flood. The mean discrepancy between epochs of drought/flood and the nodal tide since AD 1600 is 0.7 ± 2.2 yr, but the polarity of the signal is apparently bimodal. From nodal epoch 1750.0 through 1898.9 drought and tide were in phase, whereas prior to 1750.0 and subsequent to 1898.9 drought and tide were out of phase. There is evidence also for the solar cycle drought signal in the data.

  18. Spatial distribution of rock glaciers in the semi-arid Andes of Argentina

    NASA Astrophysics Data System (ADS)

    Blöthe, Jan Henrik; Halla, Christian; Schrott, Lothar; Götz, Joachim; Trombotto, Dario

    2016-04-01

    Active rock glaciers are indicators for permafrost in periglacial environments of high mountain areas. Within the permafrost body and the seasonally frozen active layer, these rock glaciers potentially store large amounts of water. Especially in semiarid mountain belts, such as the central Andes of Argentina, rock glaciers attain several kilometres in length, covering surface areas of >106 m2. Here, rock glaciers even outrange ice glaciers in cumulative area and absolute number, indicating they might constitute a large water reservoir in this semiarid part of the Andes. Despite their potential hydrological importance, our knowledge about the rock glaciers' spatial distribution, subsurface composition and absolute ice content is still very limited. Our study addresses this shortcoming and aims at assessing the hydrological significance of rock glacier permafrost in the semi-arid Andes of Argentina by combining local geophysical investigations with regional remote sensing analysis. Our research focuses on the central Andes between 30°S and 33°S, where we have compiled an inventory that comprises more than 1200 rock glaciers, as well as 154 clear-ice and debris-covered glaciers. Two field sites that bracket this regional study area towards their northern and southern edge have been selected for local geophysical investigations. At these locations, earlier studies detected the presence of rock glacier permafrost by thermal monitoring and geophysical prospection. Preliminary results of the regional spatial distribution indicate that the spatial density of rock glaciers increases towards the south, concomitant with a twofold increase in mean annual precipitation. Rock glacier density peaks in the area of the Aconcagua massif, while precipitation is further increasing towards the south. Simultaneously, the lower altitudinal limit of intact rock glaciers slightly decreases, with the lowest rock glacier toe positions in the northern study area located at ~3800 m a. s. l

  19. Tectonic geomorphology of the Andes with SIR-A and SIR-B

    NASA Technical Reports Server (NTRS)

    Bloom, Arthur L.; Fielding, Eric J.

    1986-01-01

    Data takes from SIR-A and SIR-B (Shuttle Imaging Radar) crossed all of the principal geomorphic provinces of the central Andes between 17 and 34 S latitude. In conjunction with Thematic Mapping images and photographs from hand-held cameras as well as from the Large Format Camera that was flown with SIR-B, the radar images give an excellent sampling of Andean geomorphology. In particular, the radar images show new details of volcanic rocks and landforms of late Cenozoic age in the Puna, and the exhumed surfaces of tilted blocks of Precambrian crystalline basement in the Sierras Pampeanas.

  20. Geomorphic controls on availability of weathering-derived nutrients across an erosional gradient in the Andes

    NASA Astrophysics Data System (ADS)

    West, A.; Torres, M. A.; Kleinsasser, E.; Clark, K.; Asner, G. P.; Malhi, Y.; Quesada, C.

    2013-12-01

    Rock-derived nutrients are thought to play important roles in determining ecosystem productivity and function, particularly in tropical forests. Variation in the availability of key nutrients such as P and Ca has been attributed to changes in the supply from chemical weathering of bedrock minerals, with a general conceptual model that younger soils with higher weathering rates are capable of supplying more nutrients compared to older soils with lower weathering rates (e.g. Vitousek et al., 2003). In this study we present data from an elevational gradient in the eastern Andes of Peru, illustrating how the relationship between weathering and nutrient availability is manifest in an active erosional system. Our data suggest that weathering, driven by erosional supply of primary minerals, is important in supplying nutrients. However, there is complexity in this relationship that may be associated with the geomorphic controls on weathering geochemistry and hydrochemistry, including weathering that takes place at greater depths when erosion rates are higher (e.g. West, 2012). We compare measured weathering rates with nutrient status of soils and vegetation across a transect from high elevations in the Andes to low elevations in the foreland floodplain. Weathering rates determined from the dissolved chemistry of river samples are highest at high elevation sites in the Andes. Mineral weathering rates are significant in the floodplain, which we attribute to chemical reworking of material eroded from the Andes, but rates of mineral weathering are not as high in the floodplain as in the montane sites. Although Ca supply is highest in the mountains, the foliar Ca and Ca available in soils is lower than in the floodplain. We will explore hydrochemical reasons for this difference, which may be due to where Ca release takes place relative to the vegetation root zone. We will also explore the supply of P from weathering in relation to observed nutrient availability, based on

  1. Cryptic species diversity in marsupial frogs (Anura: Hemiphractidae: Gastrotheca) in the Andes of northern Peru.

    PubMed

    Duellman, William E; Barley, Anthony J; Venegas, Pablo J

    2014-02-25

    Molecular phylogenetic analysis revealed the existence of two undescribed species of the hemiphractid genus Gastrotheca in the Andes in northern Peru. Both species are similar morphologically to Gastrotheca dysprosita and G. monticola, but they differ from these species and from one another in subtleties of coloration and minor variances in size and proportions. Gastrotheca aguaruna sp. nov. (6˚10'50"S, 77˚37'01"W, 2480 m) is from humid forested areas in the northern part of the Cordillera Central, whereas G. aratia sp. nov. (6˚14'00"S, 78˚51'24"W, 2560 m ) is known from the northern part of the Cordillera Occidental.

  2. Slab flattening driving regional uplift in the Cordilleras Blanca and Negra, Western Andes

    NASA Astrophysics Data System (ADS)

    Margirier, Audrey; Audin, Laurence; Robert, Xavier; Bernet, Matthias; Gautheron, Cécile

    2015-04-01

    The Andean range topographic evolution is known to have had a strong impact on regional climate by building an orographic barrier that preserved its western flank from the south Atlantic moisture. Even if largely invoked, the impact of subduction processes on the uplift and relief building is not yet well understood in the Andes. The northern Peru is characterized by a present day flat subduction zone (3-15°S), where both the geometry and temporal evolution of the flat-slab are well constrained. The subduction of two buoyant anomalies, the Nazca ridge and the lost Inca plateau controlled the slab flattening. The highest Peruvian peaks in the Cordillera Blanca (6768 m), and the Cordillera Negra (5187 m) are located just above the flat-slab segment. Both ranges trend parallel to the subduction zone and are separated by the NW-SE Rio Santa valley. The Cordillera Blanca batholith emplaced at 8-5 Ma and renders of an abnormal magmatic activity over a planar subduction. This area is a perfect target to explore the impact of slab flattening on the topography and uplift in the Occidental Cordillera of the Andes. We present new AHe and AFT data from three vertical profiles located in both the Cordilleras Blanca and Negra. We compare time-temperature paths obtained from inverse modeling of the thermochronological data with the timing of the slab flattening, the arrival of the Nazca ridge and magmatism. Our thermochronological data evidences a regional exhumation in the Occidental Cordillera from ~10 Ma. We propose that the Nazca ridge subduction below the Occidental Cordillera (11 Ma) and slab flattening (8 Ma) drive the Occidental Cordillera uplift and thus exhumation. We evidence the important contribution of the magmatism in the Cordillera Blanca exhumation and high relief building in the Occidental Cordillera. Our new thermochronological data highlight the control of both the subduction processes and magmatism on the paleogeography and uplift in the Andes. Finally, the

  3. Cryptococcus gattii meningoencephalitis in an HIV-negative patient from the Peruvian Andes.

    PubMed

    Gutierrez, Ericson L; Valqui, Willi; Vilchez, Luis; Evangelista, Lourdes; Crispin, Sarita; Tello, Mercedes; Navincopa, Marcos; Béjar, Vilma; Gonzáles, José; Ortega-Loayza, Alex G

    2010-01-01

    We report a case of an immunocompetent Peruvian patient from the Andes with a one-month history of meningoencephalitis. Cryptococcus gattii was identified from a cerebrospinal fluid culture through assimilation of D-proline and D-tryptophan as the single nitrogen source. Initially, the patient received intravenous antifungal therapy with amphotericin B. The patient was discharged 29 days after hospitalization and continued with oral fluconazole treatment for ten weeks. During this period, the patient showed clinical improvement with slight right-side residual weakness. Through this case report, we confirm the existence of this microorganism as an infectious agent in Peru.

  4. Integrated Assessment of Climate Variability and Change in the Tropical Peruvian Andes

    NASA Astrophysics Data System (ADS)

    Lagos, P.

    2004-12-01

    Considering that the intensity and frequency of recurrent extreme events associated with flooding, droughts and freezes observed in the tropical Peruvian Andes could change with future global warming, an effort has begun to: (1) investigate the causes of such extreme events using correlation and principal component analysis; (2) generate future climate scenarios using statistical and dynamical downscaling; (3) integrate with the studies of vulnerability and adaptation strategies in the region. The purpose of this paper is to describe the results of this effort, which is part of the national plan to strengthen the capacity to manage the impacts of climate change.

  5. Prediction of extreme floods in the Central Andes by means of Complex Networks

    NASA Astrophysics Data System (ADS)

    Boers, Niklas; Bookhagen, Bodo; Barbosa, Henrique; Marwan, Norbert; Kurths, Jürgen; Marengo, Jose

    2014-05-01

    Based on a non-linear synchronisation measure and complex network theory, we present a novel framework for the prediction of extreme events of spatially embedded, interrelated time series. This method is general in the sense that it can be applied to any type of spatially sampled time series with significant interrelations, ranging from climate observables to biological or stock market data. In this presentation, we apply our method to extreme rainfall in South America and show how this leads to the prediction of more than 60% (90% during El Niño conditions) of extreme rainfall events in the eastern Central Andes of Bolivia and northern Argentina, with only 1% false alarms. From paleoclimatic to decadal time scales, the Central Andes continue to be subject to pronounced changes in climatic conditions. In particular, our and past work shows that frequency as well as magnitudes of extreme rainfall events have increased significantly during past decades, calling for a better understanding of the involved climatic mechanisms. Due to their large spatial extend and occurrence at high elevations, these extreme events often lead to severe floods and landslides with disastrous socioeconomic impacts. They regularly affect tens of thousands of people and produce estimated costs of the order of several hundred million USD. Alongside with the societal value of predicting natural hazards, our study provides insights into the responsible climatic features and suggests interactions between Rossby waves in polar regions and large scale (sub-)tropical moisture transport as a driver of subseasonal variability of the South American monsoon system. Predictable extreme events result from the propagation of extreme rainfall from the region of Buenos Aires towards the Central Andes given characteristic atmospheric conditions. Our results indicate that the role of frontal systems originating from Rossby waves in polar latitudes is much more dominant for controlling extreme rainfall in

  6. Jürgen Stock: From One End of the Andes to the Other

    NASA Astrophysics Data System (ADS)

    Vivas, A. K.; Stock, M. J.

    2015-05-01

    Jürgen Stock (1923-2004) will always be remembered for his work on astronomical site testing. He led the efforts to find the best place for CTIO, and his work had a large influence in the setting of other observatories in Chile. He was the first director of CTIO (1963-1966). After his time in Chile, he moved to the other end of the Andes and was in charge of the site selection and the construction of the only professional observatory in Venezuela, the Llano del Hato National Observatory.

  7. Development of a minigenome system for Andes virus, a New World hantavirus.

    PubMed

    Brown, Kyle S; Ebihara, Hideki; Feldmann, Heinz

    2012-11-01

    The development of reverse genetics systems for negative-stranded RNA viruses is a rapidly evolving field that has greatly advanced the study of the many different aspects of the viral life cycle. Andes virus (ANDV) is a highly pathogenic hantavirus found in South America that causes hantavirus pulmonary syndrome but to date remains poorly characterized due to the lack of a reverse genetics system for genetic manipulation. Here, we describe the first successful minigenome system for a New World hantavirus, as well as many of the obstacles that still exist in the development of such a system.

  8. Cross-shelf exchange in the northwestern Black Sea

    NASA Astrophysics Data System (ADS)

    Zhou, Feng; Shapiro, Georgy; Wobus, Fred

    2014-04-01

    The transports of water, heat, and salt between the northwestern shelf and deep interior of the Black Sea are investigated using a high-resolution three-dimensional primitive equation model. From April to August 2005, both onshore and offshore cross-shelf break transports in the top 20 m were 0.24 Sv on average, which is equivalent to the replacement of 60% of the volume of surface shelf waters (0-20 m) per month. Two main exchange mechanisms are studied: Ekman transport, and transport by mesoscale eddies and associated meanders of the Rim Current. The Ekman drift causes nearly uniform onshore or offshore flow over a large section of the shelf break, but it is confined to the upper layers. In contrast, eddies and meanders penetrate deep down to the bottom, but they are restricted laterally. During the strong wind events of 15-22 April and 1-4 July, some 0.66 × 1012 and 0.44 × 1012 m3 of water were removed from the northwestern shelf, respectively. In comparison, the single long-lived Sevastopol Eddy generated a much larger offshore transfer of 2.84 × 1012 m3 over the period 23 April to 30 June, which is equivalent to 102% of the volume of northwestern shelf waters. Over the study period, salt exchanges increased the average density of the shelf waters by 0.67 kg m-3 and reduced the density contrast between the shelf and deep sea, while lateral heat exchanges reduced the density of the shelf waters by 0.16 kg m-3 and sharpened the shelf break front.

  9. Potential particulate impacts at the Grand Canyon from northwestern Mexico.

    PubMed

    Eatough, D J; Green, M; Moran, W; Farber, R

    2001-08-10

    Project MOHAVE was a major air quality and visibility research program conducted from 1990 to 1999 to investigate the causes of visibility impairment in the Grand Canyon National Park region. At Meadview, a remote monitoring site just west of the Grand Canyon National Park, on September 1 and 2, 1992, the concentrations of sulfate (3.1 and 4.3 microg sulfate/m3) were the highest seen in 6 years of monitoring at this site. During this period, the concentrations of SO2 at Meadview were also abnormally high and approximately three times the sulfate concentrations, on a nmol/m3 basis. High concentrations of sulfate and SO2 extended south into southern Arizona and northwestern Mexico. Based on ambient atmospheric conditions, emissions from the Mohave Power Project (MPP) 110 km upwind of Meadview could not have been responsible for the majority of the regionally observed sulfur oxides. The geographical distribution of SO2 and sulfate, and available source information suggest that northwestern Mexico was a significant source of the unusually high observed sulfur oxides. A CMB model developed during Project MOHAVE was used to apportion sulfur oxides at Meadview and other sampling sites throughout the study region for August 31-September 2, 1992. The results indicate that the contribution of MPP to sulfate at Meadview was typical. However, the transport of SOx from northwestern Mexico was elevated throughout much of the region during this time period. This led to the large increase in sulfate concentrations at Meadview on September 1 and 2. These results indicate that emissions from Mexico can be a significant source of particulate material in the Grand Canyon.

  10. Middle cretaceous carbonate reservoirs, Fahud Field and northwestern Oman: discussion

    SciTech Connect

    Brennan, P.

    1985-05-01

    A discussion is presented of the Cretaceous formations involved in Fahud field. Along the Trucial Coast, as in northwestern Oman, it is not difficult to date the time of formation of the foredeep. This article provides a stratigraphic correlation chart for the Cretaceous along the Arabian side of the Arabian Gulf. The terminology presented on this correlation chart reflects oil-industry usage in the area, including correlations published by Owen and Nasr, Loutfi and Jaber, Arabian American Oil Company, Beydoun and Dunnington, and Hassan et al.

  11. Climatic Limits on Landscape Development in the Northwestern Himalaya

    PubMed

    Brozović; Burbank; Meigs

    1997-04-25

    The interaction between tectonism and erosion produces rugged landscapes in actively deforming regions. In the northwestern Himalaya, the form of the landscape was found to be largely independent of exhumation rates, but regional trends in mean and modal elevations, hypsometry (frequency distribution of altitude), and slope distributions were correlated with the extent of glaciation. These observations imply that in mountain belts that intersect the snowline, glacial and periglacial processes place an upper limit on altitude, relief, and the development of topography irrespective of the rate of tectonic processes operating.

  12. Climate Change and Neotectonic History of Northwestern China

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Chadwick, Oliver; Evans, Diane; Gillespie, Alan; Peltzer, Gilles; Tapponnier, Paul

    1996-01-01

    The progress, results and future plans for the following objectives are presented: (1) To compare the types, rates, and magnitudes of surficial modification processes that have operated in Northwest China and the Southwestern U.S.; (2) To quantify and understand the basis of the remote sensing signatures of these processes to allow extrapolation from field sites to regional maps and to allow comparisons between widely separated arid regions; (3) To use the resulting chronologies to help define the temporal and spatial distribution of continental climate changes; and (4) Determine the ages of movements on some of the active faults in Northwestern China.

  13. African Oral Traditions: Riddles Among The Haya of Northwestern Tanzania

    NASA Astrophysics Data System (ADS)

    Ishengoma, Johnson M.

    2005-05-01

    This study argues for the integration of African oral traditions and other elements of traditional learning into the modern school curriculum. It thus contributes to supporting the increased relevance of education to local communities. In particular, using the example of riddles collected from one of the main ethnic groups in Northwestern Tanzania, the Haya people, the present study challenges the views of those social and cultural anthropologists who hold that African riddles have no substantially meaningful educational value. Instead, it is maintained that riddles make an important contribution to children's full participation in the social, cultural, political, and economic life of African communities, especially by fostering critical thinking and transmitting indigenous knowledge.

  14. Rapid fluvial aggradation in response to climate change in northwestern Argentina

    NASA Astrophysics Data System (ADS)

    Wickert, Andrew; Schildgen, Taylor; Strecker, Manfred

    2015-04-01

    River channels near the edge of the northwestern Argentine Andes are rapidly aggrading at present, with preliminary estimates suggesting rates of ~20 cm yr-1. This mirrors cycles of extensive aggradation over the past 100,000 years that formed pronounced fill terraces along regional valley networks and record periods in which in which climate-driven sediment supply overcame uplift-driven river incision (Robinson et al, 2005). Here we use the new SedFlow model (Heimann et al., 2014) to help us understand the causes and spread of aggradation across these basins in the modern system, with the additional eventual goal to better interpret the geologic record. We provide field-derived grain-size distributions, field-measured and remotely-sensed channel widths and valley slopes, and a variety of possible sediment source locations and amounts as inputs to SedFlow, which routes sediment through the fluvial channel network to produce time-evolving predictions of aggradation and incision. We compare these predictions against changes in topography measured by IceSAT (Zwally et al., 2014) and field surveys. We initially test the system response to a series of isolated sediment inputs to observe interactions between tributary systems and the mainstem river. Recent observations indicate that debris-flow induced landslides are important contributors to aggradation in these rivers (Cencetti and Rivelli, 2011). These and other sediment production and transport processes are likely driven by variations in the El Niño Southern Oscillation (ENSO) (Bookhagen and Strecker, 2009). Therefore, we then run SedFlow with sediment inputs distributed across the landscape based on locations where ENSO influences may trigger enhanced landsliding. These model experiments help us towards our end goal of providing a more quantitative basis to interpret field observations of landscape response to changing patterns of precipitation. References: Bookhagen, B. and Strecker, M.: Amazonia: Landscape and

  15. The Center for Talent Development at Northwestern University: An Example of Replication and Reformation

    ERIC Educational Resources Information Center

    Olszewski-Kubilius, Paula

    2005-01-01

    This article describes implementation of the talent search model developed by Julian Stanley at the Center for Talent Development of Northwestern University. While remaining true to the basic components of the talent search, the talent center at Northwestern has emphasized using talent search as a means to influence programming in local schools…

  16. Descriptions and illustrations of fossils from Vancouver's and Sucia Islands, and other northwestern localities

    USGS Publications Warehouse

    Meek, F.B.

    1876-01-01

    The fossils described and illustrated in this paper were in part collected by Mr. George Gibbs, geologist of the Northwestern Boundary Survey, under the direction of Archibald Campbell, esq., the commissioner appointed in behalf of the United States Government on the joint commission for the survey of the Northwestern Boundary-line.

  17. 75 FR 6790 - Nebraska Northwestern Railroad, Inc.-Acquisition and Operation Exemption-Dakota, Minnesota...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-10

    ... Surface Transportation Board Nebraska Northwestern Railroad, Inc.--Acquisition and Operation Exemption--Dakota, Minnesota & Eastern Railroad Corporation Nebraska Northwestern Railroad, Inc. (NNW), a noncarrier... Dakota, Minnesota & Eastern Railroad Corporation (DM&E) and to operate approximately 28.1 miles of...

  18. 76 FR 26717 - NorthWestern Corporation; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission NorthWestern Corporation; Notice of Baseline Filing Take notice that on April 29, 2011, NorthWestern Corporation submitted a revised baseline filing of their Statement...

  19. 76 FR 28017 - NorthWestern Corporation; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-13

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission NorthWestern Corporation; Notice of Baseline Filing Take notice that on May 5, 2011, NorthWestern Corporation submitted a revised baseline filing of their Statement...

  20. Modeling modern glacier response to climate changes along the Andes Cordillera: A multiscale review

    NASA Astrophysics Data System (ADS)

    Fernández, Alfonso; Mark, Bryan G.

    2016-03-01

    Here we review the literature preferentially concerned with modern glacier-climate modeling along the Andes. We find a diverse range of modeling approaches, from empirical/statistical models to relatively complex energy balance procedures. We analyzed these models at three different spatial scales. First, we review global approaches that have included the Andes. Second, we depict and analyze modeling exercises aimed at studying Andean glaciers as a whole. Our revision shows only two studies dealing with glacier modeling at this continental scale. We contend that this regional approach is increasingly necessary because it allows for connecting the "average-out" tendency of global studies to local observations or models, in order to comprehend scales of variability and heterogeneity. Third, we revise small-scale modeling, finding that the overwhelming number of studies have targeted glaciers in Patagonia. We also find that most studies use temperature-index models and that energy balance models are still not widely utilized. However, there is no clear spatial pattern of model complexity. We conclude with a discussion of both the limitations of certain approaches, as for example the use of short calibration periods for long-term modeling, and also the opportunities for improved understanding afforded by new methods and techniques, such as climatic downscaling. We also propose ways to future developments, in which observations and models can be combined to improve current understanding of volumetric glacier changes and their climate causes.

  1. Remote Sensing of Snow as a Tool to Forecast Water Shortage in the Argentinian Dry Andes

    NASA Astrophysics Data System (ADS)

    Delbart, Nicolas; Dunesme, Samuel; Lavie, Emilie; Madelin, Malika

    2016-08-01

    In the Argentinian Dry Andes the annual snow melt is the main source of superficial water and aquifer recharge, essential for the population of the oases. Interannual variability in the snow cover in the Andes mountains causes variability in the water volumes available. In this study we analyze the errors of a water discharge forecast method based on the MODIS MOD10A2 snow cover product, with regards to the mass anomalies estimated by GRACE satellite at the scale of four watersheds.Because the high-water period (September-April) discharge is directly related to the snow extent at the beginning of the snowmelt period, i.e. in September and October, we use MOD10A2 images to forecast the average high water season discharge. Despite an average uncertainty of 15%, uncertainty peaks to about 50% in several years. Comparison with mass anomalies retrieved GRACE satellite data suggests that overestimation of our forecast method comes from snowbed thickness interannual variations.

  2. Geomorphic Response to Flat Slab Subduction along the Eastern Foothills of the Colombian Andes

    NASA Astrophysics Data System (ADS)

    Veloza, G.; Taylor, M. H.; Gosse, J. C.; Mora, A.; Becker, T. W.

    2013-12-01

    It is thought that in northwest South America flat slab subduction plays a key role in the recent development of the eastern Colombian Andes. Here we show that the geomorphic response to flat slab subduction is presently occurring >500 km inboard of the subduction zone plate boundary. The Llanos basin located along the eastern edge of the Colombian Andes is experiencing active uplift along the seismically active Cusiana, Yopal, Paz de Ariporo and Tame thrust faults, which we refer to as the Llanos Foothills thrust system (LFTS). The LFTS is comprised of east-directed thrust faults that are listric in geometry with shallowly west-dipping decollements. Locally, actively growing north-south plunging folds are cored by blind thrust faults, and are being incised by antecedent east-flowing streams. Using a combination of field-based observations on the geometry of faulted and folded fluvial terraces, and geochronology from terrestrial cosmogenic nuclides, we show that the fluvial terraces have been uplifted, and locally, incised >200 meters at incision rates exceeding 3 mm/yr. The field observations in combination with earthquakes and geodynamic simulations can be reconciled by flat slab subduction, but it is presently unknown whether the flat slab has a Caribbean or Nazca plate affinity. Different geodynamic scenarios can be tested to understand how the leading edge of the flat slab interacts with the South American craton, and how that interaction controls upper crustal deformation.

  3. Quaternary Ice-Age dynamics in the Colombian Andes: developing an understanding of our legacy.

    PubMed Central

    Hooghiemstra, Henry; Van der Hammen, Thomas

    2004-01-01

    Pollen records from lacustrine sediments of deep basins in the Colombian Andes provide records of vegetation history, the development of the floristic composition of biomes, and climate variation with increasing temporal resolution. Local differences in the altitudinal distribution of present-day vegetation belts in four Colombian Cordilleras are presented. Operating mechanisms during Quaternary Ice-Age cycles that stimulated speciation are discussed by considering endemism in the asteraceous genera Espeletia, Espeletiopsis and Coespeletia. The floristically diverse lower montane forest belt (1000-2300 m) was compressed by ca. 55% during the last glacial maximum (LGM) (20 ka), and occupied the slopes between 800 m and 1400 m during that period. Under low LGM atmospheric pCO2 values, C4-dominated vegetation, now occurring below 2200 m, expanded up to ca. 3500 m. Present-day C3-dominated paramo vegetation is therefore not an analogue for past C4-dominated vegetation (with abundant Sporobolus lasiophyllus). Quercus immigrated into Colombia 478 ka and formed an extensive zonal forest from 330 ka when former Podocarpus-dominated forest was replaced by zonal forest with Quercus and Weinmannia. During the last glacial cycle the ecological tolerance of Quercus may have increased. In the ecotone forests Quercus was rapidly and massively replaced by Polylepis between 45 and 30 ka illustrating complex forest dynamics in the tropical Andes. PMID:15101574

  4. Late Pleistocene equilibrium-line reconstructions in the northern Peruvian Andes

    USGS Publications Warehouse

    Rodbell, D.T.

    1992-01-01

    ELA reconstructions using the toe-to-headwall-altitude ratio method for paleoglaciers in the Cordilleras Blanca and Oriental, northern Peruvian Andes indicate that ELAs during the last glacial maximum (LGM; marine isotope stage 2)) were c.4300 m in the Cordillera Blanca, c.3900-3600 m on the west side of the Cordillera Oriental, and c.3200 m on the east (Amazon Basin) side of the Cordillera Oriental. Comparison with estimated modern ELAs and glaciation thresholds indicate that ELA depression ranged from c.700 m in the Cordillera Blanca to c.1200 m on the east side of the Cordillera Oriental. Palynological evidence for drier conditions during the LGM in the tropical Andes suggests that ELA depression of this amount involved a temperature reduction (>5-6??C) that greatly exceeded the tropical sea-surface temperature depression estimates of CLIMAP (<2??C). The west to east increase in ELA depression during the LGM indicates that the steep modern precipitation gradients may have been even steeper during the LGM. -from Author

  5. Thermal physiology, disease, and amphibian declines on the eastern slopes of the Andes.

    PubMed

    Catenazzi, Alessandro; Lehr, Edgar; Vredenburg, Vance T

    2014-04-01

    Rising temperatures, a widespread consequence of climate change, have been implicated in enigmatic amphibian declines from habitats with little apparent human impact. The pathogenic fungus Batrachochytrium dendrobatidis (Bd), now widespread in Neotropical mountains, may act in synergy with climate change causing collapse in thermally stressed hosts. We measured the thermal tolerance of frogs along a wide elevational gradient in the Tropical Andes, where frog populations have collapsed. We used the difference between critical thermal maximum and the temperature a frog experiences in nature as a measure of tolerance to high temperatures. Temperature tolerance increased as elevation increased, suggesting that frogs at higher elevations may be less sensitive to rising temperatures. We tested the alternative pathogen optimal growth hypothesis that prevalence of the pathogen should decrease as temperatures fall outside the optimal range of pathogen growth. Our infection-prevalence data supported the pathogen optimal growth hypothesis because we found that prevalence of Bd increased when host temperatures matched its optimal growth range. These findings suggest that rising temperatures may not be the driver of amphibian declines in the eastern slopes of the Andes. Zoonotic outbreaks of Bd are the most parsimonious hypothesis to explain the collapse of montane amphibian faunas; but our results also reveal that lowland tropical amphibians, despite being shielded from Bd by higher temperatures, are vulnerable to climate-warming stress.

  6. Bird conservation would complement landslide prevention in the Central Andes of Colombia

    PubMed Central

    Ocampo-Peñuela, Natalia

    2015-01-01

    Conservation and restoration priorities often focus on separate ecosystem problems. Inspired by the November 11th (2011) landslide event near Manizales, and the current poor results of Colombia’s Article 111 of Law 99 of 1993 as a conservation measure in this country, we set out to prioritize conservation and restoration areas where landslide prevention would complement bird conservation in the Central Andes. This area is one of the most biodiverse places on Earth, but also one of the most threatened. Using the case of the Rio Blanco Reserve, near Manizales, we identified areas for conservation where endemic and small-range bird diversity was high, and where landslide risk was also high. We further prioritized restoration areas by overlapping these conservation priorities with a forest cover map. Restoring forests in bare areas of high landslide risk and important bird diversity yields benefits for both biodiversity and people. We developed a simple landslide susceptibility model using slope, forest cover, aspect, and stream proximity. Using publicly available bird range maps, refined by elevation, we mapped concentrations of endemic and small-range bird species. We identified 1.54 km2 of potential restoration areas in the Rio Blanco Reserve, and 886 km2 in the Central Andes region. By prioritizing these areas, we facilitate the application of Article 111 which requires local and regional governments to invest in land purchases for the conservation of watersheds. PMID:25737819

  7. A new species of Telmatobius (Amphibia, Anura, Telmatobiidae) from the Pacific slopes of the Andes, Peru.

    PubMed

    Catenazzi, Alessandro; García, Víctor Vargas; Lehr, Edgar

    2015-01-01

    We describe a new species of Telmatobius from the Pacific slopes of the Andes in central Peru. Specimens were collected at 3900 m elevation near Huaytará, Huancavelica, in the upper drainage of the Pisco river. The new species has a snout-vent length of 52.5 ± 1.1 mm (49.3-55.7 mm, n = 6) in adult females, and 48.5 mm in the single adult male. The new species has bright yellow and orange coloration ventrally and is readily distinguished from all other central Peruvian Andean species of Telmatobius but Telmatobiusintermedius by having vomerine teeth but lacking premaxillary and maxillary teeth, and by its slender body shape and long legs. The new species differs from Telmatobiusintermedius by its larger size, flatter head, and the absence of cutaneous keratinized spicules (present even in immature females of Telmatobiusintermedius), and in males by the presence of minute, densely packed nuptial spines on dorsal and medial surfaces of thumbs (large, sparsely packed nuptial spines in Telmatobiusintermedius). The hyper-arid coastal valleys of Peru generally support low species richness, particularly for groups such as aquatic breeding amphibians. The discovery of a new species in this environment, and along a major highway crossing the Andes, shows that much remains to be done to document amphibian diversity in Peru.

  8. Glacier change and glacial lake outburst flood risk in the Bolivian Andes

    NASA Astrophysics Data System (ADS)

    Cook, Simon J.; Kougkoulos, Ioannis; Edwards, Laura A.; Dortch, Jason; Hoffmann, Dirk

    2016-10-01

    Glaciers of the Bolivian Andes represent an important water resource for Andean cities and mountain communities, yet relatively little work has assessed changes in their extent over recent decades. In many mountain regions, glacier recession has been accompanied by the development of proglacial lakes, which can pose a glacial lake outburst flood (GLOF) hazard. However, no studies have assessed the development of such lakes in Bolivia despite recent GLOF incidents here. Our mapping from satellite imagery reveals an overall areal shrinkage of 228.1 ± 22.8 km2 (43.1 %) across the Bolivian Cordillera Oriental between 1986 and 2014. Shrinkage was greatest in the Tres Cruces region (47.3 %), followed by the Cordillera Apolobamba (43.1 %) and Cordillera Real (41.9 %). A growing number of proglacial lakes have developed as glaciers have receded, in accordance with trends in most other deglaciating mountain ranges, although the number of ice-contact lakes has decreased. The reasons for this are unclear, but the pattern of lake change has varied significantly throughout the study period, suggesting that monitoring of future lake development is required as ice continues to recede. Ultimately, we use our 2014 database of proglacial lakes to assess GLOF risk across the Bolivian Andes. We identify 25 lakes that pose a potential GLOF threat to downstream communities and infrastructure. We suggest that further studies of potential GLOF impacts are urgently required.

  9. Surface uplift in the Central Andes driven by growth of the Altiplano Puna Magma Body

    PubMed Central

    Perkins, Jonathan P.; Ward, Kevin M.; de Silva, Shanaka L.; Zandt, George; Beck, Susan L.; Finnegan, Noah J.

    2016-01-01

    The Altiplano-Puna Magma Body (APMB) in the Central Andes is the largest imaged magma reservoir on Earth, and is located within the second highest orogenic plateau on Earth, the Altiplano-Puna. Although the APMB is a first-order geologic feature similar to the Sierra Nevada batholith, its role in the surface uplift history of the Central Andes remains uncertain. Here we show that a long-wavelength topographic dome overlies the seismically measured extent of the APMB, and gravity data suggest that the uplift is isostatically compensated. Isostatic modelling of the magmatic contribution to dome growth yields melt volumes comparable to those estimated from tomography, and suggests that the APMB growth rate exceeds the peak Cretaceous magmatic flare-up in the Sierran batholith. Our analysis reveals that magmatic addition may provide a contribution to surface uplift on par with lithospheric removal, and illustrates that surface topography may help constrain the magnitude of pluton-scale melt production. PMID:27779183

  10. Recent Seismic and Geodetic Activity at Multiple Volcanoes in the Ecuadorean Andes

    NASA Astrophysics Data System (ADS)

    Hernandez, S.; Ruiz, M. C.; McCausland, W. A.; Prejean, S. G.; Mothes, P. A.; Bell, A. F.; Hidalgo, S.; Barrington, C.; Yepez, M.; Aguaiza, S.; Plain, M.

    2015-12-01

    The state of volcanic activity often fluctuates between periods of repose and unrest. The transition time between a period of repose and unrest, or vice versa for an open system, can occur within a matter of hours or days. Because of this short time scale, real-time seismic and geodetic (e.g. tiltmeter, GPS) monitoring networks are crucial for characterizing the state of activity of a volcano. In the Ecuadorean Andes, 5 volcanoes demonstrate long-term (Tungurahua, Reventador, and Guagua Pichincha) or recently reactivated (Cotopaxi, Chiles-Cerro Negro) seismic and geodetic activity. The Instituto Geofisico regularly characterizes volcano seismicity into long period, very long period, volcano-tectonic, and tremor events. Significant recent changes at these volcanoes include: rigorous reactivation of glacier-capped Cotopaxi, drumbeat seismicity absent a dome extrusion at Tungurahua, and regularly reoccurring (~7 day recurrence interval), shallow seismic swarms at Guagua Pichincha. These volcanoes locate along both the Western and Eastern Cordillera of the Ecuadorean Andes and, where data are available, manifest important variations in chemical composition, daily gas flux, and surficial deformation. We summarize the long-term geophysical parameters measured at each volcano and place recent changes in each parameter in a larger magmatic and hydrothermal context. All of the studied volcanoes present significant societal hazards to local and regional communities.

  11. Temperature and Rainfall Variability in the Northern Andes Over the Past Two Millennia

    NASA Astrophysics Data System (ADS)

    Shanahan, T. M.; Bixler, C. W.; Mora, A.

    2014-12-01

    Recent studies of tropical glaciers have shown that most are retreating rapidly, with some of the most dramatic changes occurring since the mid-1970s, most likely as a result of increasing global temperatures. However, a longer-term perspective is needed to place these changes in the context of natural climate variability. To better understand the climatological factors driving long-term variations in the mass balance of tropical glaciers, we reconstructed changes in precipitation and temperature in the northern tropical Andes using variations in the hydrogen isotope composition of sedimentary leaf waxes and branched GDGT distributions in a high-resolution varved sediment record from Lago Chingaza, Colombia. Br-GDGT derived temperatures are significantly correlated with instrumental temperature data and indicate that recent warming in the northern tropical Andes is unprecedented over the past two millennia. Furthermore, the magnitude of warming since the Little Ice Age is substantially larger than suggested by high latitude temperature reconstructions. Hydrogen isotope data indicated that colder conditions during the Little Ice Age were accompanied by a decrease in rainfall, likely associated with a southward shift in the position of the ITCZ. Over the past few centuries, warmer temperatures were accompanied by an increase in rainfall and a northward expansion of the tropical rainbelt. Together, these data suggest that the dominant control on the retreat of Andean glaciers has been the unprecedented rate and magnitude of recent warming.

  12. Comparative Phylogeography of Direct-Developing Frogs (Anura: Craugastoridae: Pristimantis) in the Southern Andes of Colombia

    PubMed Central

    García-R, Juan C.; Crawford, Andrew J.; Mendoza, Ángela María; Ospina, Oscar; Cardenas, Heiber; Castro, Fernando

    2012-01-01

    The Andes of South America hosts perhaps the highest amphibian species diversity in the world, and a sizable component of that diversity is comprised of direct-developing frogs of the genus Pristimantis (Anura: Craugastoridae). In order to better understand the initial stages of species formation in these frogs, this study quantified local-scale spatial genetic structuring in three species of Pristimantis. DNA sequences of two mitochondrial gene fragments (16S and COI) were obtained from P. brevifrons, P. palmeri and P. jubatus at different locations in the Cordillera Occidental. We found high levels of genetic diversity in the three species, with highly structured populations (as measured by FST) in P. brevifrons and P. palmeri while P. jubatus showed panmixia. Large effective population sizes, inferred from the high levels of genetic diversity, were found in the three species and two highly divergent lineages were detected within P. jubatus and P. palmeri. Estimated divergence times among populations within P. brevifrons and P. palmeri coincide with the Pleistocene, perhaps due to similar responses to climatic cycling or recent geological history. Such insights have important implications for linking alpha and beta diversity, suggesting regional scale patterns may be associated with local scale processes in promoting differentiation among populations in the Andes. PMID:23049941

  13. Permafrost distribution map of San Juan Dry Andes (Argentina) based on rock glacier sites

    NASA Astrophysics Data System (ADS)

    Esper Angillieri, María Yanina

    2017-01-01

    Rock glaciers are frozen water reservoirs in mountainous areas. Water resources are important for the local populations and economies. The presence of rock glaciers is commonly used as a direct indicator of mountain permafrost conditions. Over 500 active rock glaciers have been identified, showing that elevations between 3500 and 4500 m asl., a south-facing or east-facing aspect, areas with relatively low solar radiation and low mean annual air temperature (-4 to 0 °C) favour the existence of rock glaciers in this region. The permafrost probability model, for Dry Andes of San Juan Province between latitudes 28º30‧S and 32°30‧S, have been analyzed by logistic regression models based on the active rock glaciers occurrence in relation to some topoclimatic variables such as altitude, aspect, mean annual temperature, mean annual precipitation and solar radiation, using optical remote sensing techniques in a GIS environment. The predictive performances of the model have been estimated by known rock glaciers locations and by the area under the receiver operating characteristic curve (AUROC). This regional permafrost map can be applied by the Argentinean Government for their recent initiatives which include creating inventories, monitoring and studying ice masses along the Argentinean Andes. Further, this generated map provides valuable input data for permafrost scenarios and contributes to a better understanding of our geosystem.

  14. Unearthing the basement of the Central Andes: insights from crustal xenoliths

    NASA Astrophysics Data System (ADS)

    McLeod, C. L.; Davidson, J. P.; Nowell, G.; de Silva, S. L.

    2011-12-01

    The continental crust of the Central Andes is the thickest at any subduction on Earth today reaching an estimated 80 km in thickness (Zandt et al., 1994). However, little is known about the nature and geological evolution of the crustal basement upon which the Central Andes sit due to the extensive sedimentary cover sequences which blanket the region today. Crustal xenoliths entrained within Plio-Pleistocene andesitic-dacitic lavas on the Bolivian Altiplano offer a rare insight into the nature of the poorly exposed Central Andean basement. The samples are lithologically diverse ranging from almost pure quartzite to garnet-mica schists, with rarer granulites and several igneous lithologies including diorites and microgranites. This diversity is reflected in their significant geochemical heterogeneity (87Sr/86Sr: 0.7105-0.7445; 143Nd/144Nd: 0.5118-0.5123; 208Pb/204Pb: 17.25-18.93). Relative trace element abundances and P-T estimates are consistent with sampling of the upper continental crust at ~23 km depth. Additionally these xenoliths provide key crustal end-member compositions for modelling the petrogenesis of Central Andean volcanic rocks. It is hoped that in-situ U-Pb analysis of zircon within this rock suite will provide further insights into the nature and evolution of the Central Andean continental crust. References Zandt, G., Velasco, A. A., and Beck, S. L., (1994). Composition and thickness of southern Altiplano crust, Bolivia. Geology v. 22, pp: 1003-1006.

  15. Altitudinal variation in fish assemblage diversity in streams of the central Andes of Colombia.

    PubMed

    Jaramillo-Villa, U; Maldonado-Ocampo, J A; Escobar, F

    2010-06-01

    This study documents differences in fish assemblages for 32 freshwater streams located between 258 and 2242 m a.s.l. on the eastern slopes of the central range of the Colombian Andes. A total of 2049 fishes belonging to 62 species, 34 genera and 16 families were collected. Species richness declined rapidly with altitude; nearly 90% of the species were recorded between 250 and 1250 m a.s.l. Three of the four physico-chemical variables, of the water, temperature, dissolved oxygen and pH, explained 53.5% of the variation in species richness along the altitudinal gradient, with temperature the most important (37.6%). An analysis of species composition showed that the distinctiveness of the fish fauna increased with elevation, with the greatest turnover observed between 1000 and 1750 m a.s.l. On this altitudinal gradient, turnover was dominated by the loss of species rather than gain, and dominance by just a few species was greater at higher elevations. Turnover was also observed along the altitudinal gradient in the structure of the three functional groups (torrential, pool and pelagic species). The study focused on understanding the pattern of diversity of fish communities inhabiting the Andes in Colombia. Anthropogenic effects on the altitudinal distribution of fish species in the region, however, are largely unknown and would require further investigations.

  16. Regionalisation of Hydrological Indices to Assess Land-Use Change Impacts in the Tropical Andes

    NASA Astrophysics Data System (ADS)

    Buytaert, W.; Ochoa Tocachi, B. F.

    2014-12-01

    Andean ecosystems are major water sources for cities and communities located in the Tropical Andes; however, there is a considerable lack of knowledge about their hydrology. Two problems are especially important: (i) the lack of monitoring to assess the impacts of historical land-use and cover change and degradation (LUCCD) at catchment scale, and (ii) the high variability in climatic and hydrological conditions that complicate the evaluation of land management practices. This study analyses how a reliable LUCCD impacts assessment can be performed in an environment of high variability combined with data-scarcity and low-quality records. We use data from participatory hydrological monitoring activities in 20 catchments distributed along the tropical Andes. A set of 46 hydrological indices is calculated and regionalized by relating them to 42 physical catchment properties. Principal Component Analysis (PCA) is performed to maximise available data while minimising redundancy in the sets of variables. Hydrological model parameters are constrained by estimated indices, and different behavioural predictions are assembled to provide a generalised response on which we assess LUCCD impacts. Results from this methodology show that the attributed effects of LUCCD in pair-wise catchment comparisons may be overstated or hidden by different sources of uncertainty, including measurement inaccuracies and model structural errors. We propose extrapolation and evaluation in ungauged catchments as a way to regionalize LUCCD predictions and to provide statistically significant conclusions in the Andean region. These estimations may deliver reliable knowledge to evaluate the hydrological impact of different watershed management practices.

  17. Orographic precipitation gradient over the west slope of the Andes at 30 degrees south

    NASA Astrophysics Data System (ADS)

    Scaff, M. L.; Rutllant, J. A.; Rondanelli, R. F.

    2011-12-01

    The Elqui valley around 30°S in Chile is located within a semi-arid region in which the mean annual precipitation (80-180 mm) accumulates in austral winter in connection with mid-latitude weather disturbances: fronts and cut-off lows. Given the steep topography of the Andes in this region (0 - 5000 m in ~ 200 km) the flow and precipitation are strongly influenced by the Andes. Typically, the precipitation increases with elevation due to the forced ascent over the topography in a well-mixed atmosphere. However, it has been observed that some particular storms produce an inverse orographic precipitation gradient (OPG). An eventual increase in the frequency of this type of storms would lead to decreased water availability during the warm, rainless season and consequently to the damming capacity of the watershed. Therefore, clarifying the mechanism that produce either positive or negative OPGs within individual storms may shed light on the issue of expected climate variability. In this work we characterize OPGs according to the Froude number and associated intensity and location of the barrier jet when orographic blocking occurs. The flow blocking and stability parameters will be estimated using CFSR Reanalysis winds and temperatures along the slope from surface weather stations. These results are contrasted with studies over the Sierra Nevada that show a negative correlation between the height of the barrier jet and OPGs, and also a positive correlation between Froude number and a OPG.

  18. Perspectives from Meteorological Measurements on High Elevation Ice Caps in the Topical Andes

    NASA Astrophysics Data System (ADS)

    Bradley, R. S.; Hardy, D. R.; Diaz, H. F.

    2008-12-01

    IPCC model simulations show that large temperature changes can be expected in the high mountains of the Tropics due to anthropogenic greenhouse gas increases. Many of these areas are extensively glacierized, and so contain important water resources for the region as a whole. However, the highest mountains are devoid of meteorological measurements, so detection of changes from instrumental records is problematical. This is a critical 'data gap' in the global observing network. In an attempt to remedy this situation, hourly meteorological measurements have been made over the last decade at several high elevation ice cap and glacier sites in the tropical Andes, from Bolivia to Ecuador. These provide insight into contemporary conditions at elevations far above any long-term weather stations. The measurements complement ice core records which suggest that recent changes are unique in the context of the last millennium. We examine the meteorological data and their implications for the interpretation of the ice core records. We also discuss large-scale changes in atmospheric (free air) freezing levels in the Tropics and the factors that control such changes, with implications for the paleo record. Finally, we discuss the recent establishment of a high elevation observing network along the crest of the Tropical Andes, and argue for a Pan-American Cordilleran transect of high mountain meteorological stations, from Alaska to southern Chile.

  19. A new species of Telmatobius (Amphibia, Anura, Telmatobiidae) from the Pacific slopes of the Andes, Peru

    PubMed Central

    Catenazzi, Alessandro; García, Víctor Vargas; Lehr, Edgar

    2015-01-01

    Abstract We describe a new species of Telmatobius from the Pacific slopes of the Andes in central Peru. Specimens were collected at 3900 m elevation near Huaytará, Huancavelica, in the upper drainage of the Pisco river. The new species has a snout–vent length of 52.5 ± 1.1 mm (49.3–55.7 mm, n = 6) in adult females, and 48.5 mm in the single adult male. The new species has bright yellow and orange coloration ventrally and is readily distinguished from all other central Peruvian Andean species of Telmatobius but Telmatobius intermedius by having vomerine teeth but lacking premaxillary and maxillary teeth, and by its slender body shape and long legs. The new species differs from Telmatobius intermedius by its larger size, flatter head, and the absence of cutaneous keratinized spicules (present even in immature females of Telmatobius intermedius), and in males by the presence of minute, densely packed nuptial spines on dorsal and medial surfaces of thumbs (large, sparsely packed nuptial spines in Telmatobius intermedius). The hyper-arid coastal valleys of Peru generally support low species richness, particularly for groups such as aquatic breeding amphibians. The discovery of a new species in this environment, and along a major highway crossing the Andes, shows that much remains to be done to document amphibian diversity in Peru. PMID:25685025

  20. A continuum model of continental deformation above subduction zones - Application to the Andes and the Aegean

    NASA Technical Reports Server (NTRS)

    Wdowinski, Shimon; O'Connell, Richard J.; England, Philip

    1989-01-01

    A continuum model of continental deformation above subduction zones was developed that combines the viscous sheet and the corner flow models; the continental lithosphere is described by a two-dimensional sheet model that considers basal drag resulting from the viscous asthenosphere flow underneath, and a corner flow model with a deforming overlying plate and a rigid subducting plate is used to calculate the shear traction that acts on the base of the lithosphere above a subduction zone. The continuum model is applied to the Andes and the Aegean deformations, which represent, respectively, compressional and extensional tectonic environments above subduction zones. The models predict that, in a compressional environment, a broad region of uplifted topography will tend to develop above a more steeply dippping slab, rather than above a shallower slab, in agreement with observations in the various segments of the central Andes. For an extensional environment, the model predicts that a zone of compression can develop near the trench, and that extensional strain rate can increase with distance from the trench, as is observed in the Aegean.

  1. Bird conservation would complement landslide prevention in the Central Andes of Colombia.

    PubMed

    Ocampo-Peñuela, Natalia; Pimm, Stuart L

    2015-01-01

    Conservation and restoration priorities often focus on separate ecosystem problems. Inspired by the November 11th (2011) landslide event near Manizales, and the current poor results of Colombia's Article 111 of Law 99 of 1993 as a conservation measure in this country, we set out to prioritize conservation and restoration areas where landslide prevention would complement bird conservation in the Central Andes. This area is one of the most biodiverse places on Earth, but also one of the most threatened. Using the case of the Rio Blanco Reserve, near Manizales, we identified areas for conservation where endemic and small-range bird diversity was high, and where landslide risk was also high. We further prioritized restoration areas by overlapping these conservation priorities with a forest cover map. Restoring forests in bare areas of high landslide risk and important bird diversity yields benefits for both biodiversity and people. We developed a simple landslide susceptibility model using slope, forest cover, aspect, and stream proximity. Using publicly available bird range maps, refined by elevation, we mapped concentrations of endemic and small-range bird species. We identified 1.54 km(2) of potential restoration areas in the Rio Blanco Reserve, and 886 km(2) in the Central Andes region. By prioritizing these areas, we facilitate the application of Article 111 which requires local and regional governments to invest in land purchases for the conservation of watersheds.

  2. Intraseasonal variability of organized convective systems in the Central Andes: Relationship to Regional Dynamical Features

    NASA Astrophysics Data System (ADS)

    Mohr, K. I.; Slayback, D. A.; Nicholls, S.; Yager, K.

    2013-12-01

    The Andes extend from the west coast of Colombia (10N) to the southern tip of Chile (53S). In southern Peru and Bolivia, the Central Andes is split into separate eastern and western cordilleras, with a high plateau (≥ 3000 m), the Altiplano, between them. Because 90% of the Earth's tropical mountain glaciers are located in the Central Andes, our study focuses on this region, defining its zonal extent as 7S-21S and the meridional extent as the terrain 1000 m and greater. Although intense convection occurs during the wet season in the Altiplano, it is not included in the lists of regions with frequent or the most intense convection. The scarcity of in-situ observations with sufficient density and temporal resolution to resolve individual storms or even mesoscale-organized cloud systems and documented biases in microwave-based rainfall products in poorly gauged mountainous regions have impeded the development of an extensive literature on convection and convective systems in this region. With the tropical glaciers receding at unprecedented rates, leaving seasonal precipitation as an increasingly important input to the water balance in alpine valley ecosystems and streams, understanding the nature and characteristics of the seasonal precipitation becomes increasingly important for the rural economies in this region. Previous work in analyzing precipitation in the Central Andes has emphasized interannual variability with respect to ENSO, this is the first study to focus on shorter scale variability with respect to organized convection. The present study took advantage of the University of Utah's Precipitation Features database compiled from 14 years of TRMM observations (1998-2012), supplemented by field observations of rainfall and streamflow, historical gauge data, and long-term WRF-simulations, to analyze the intraseasonal variability of precipitating systems and their relationship regional dynamical features such as the Bolivian High. Through time series and

  3. Prevalence of anemia in First Nations children of northwestern Ontario.

    PubMed Central

    Whalen, E. A.; Caulfield, L. E.; Harris, S. B.

    1997-01-01

    OBJECTIVE: To estimate the prevalence of anemia among First Nations children of northwestern Ontario. DESIGN: Retrospective review of all hemoglobin determinations between 1990 and 1992 in the Sioux Lookout Zone. SETTING: The Sioux Lookout Zone Hospital, a secondary care referral hospital for 28 remote First Nations communities in northwestern Ontario, affiliated with the University of Toronto's Sioux Lookout Program. PARTICIPANTS: All First Nations children age 3 to 60 months who had produced venipuncture or fingerprick blood samples between 1990 and 1992 (614 children had a total of 1223 hemoglobin determinations). MAIN OUTCOME MEASURES: Prevalence of anemia by age, sex, geographical location, and diagnosis. Anemia was defined as a hemoglobin value less than 110g/L. RESULTS: Prevalence of anemia peaked in the age range of 6 to 24 months with prevalence rates of 51.7% to 79.3%. Conditions most commonly associated with anemia were respiratory tract infections. Children living in communities in the western part of the Sioux Lookout Zone were 1.64 times more likely to have anemia (95% confidence interval 1.15, 2.35) than children in the other communities. CONCLUSIONS: Anemia appears to be a serious public health problem among preschool children in the Sioux Lookout Zone. PMID:9111982

  4. Lay theory of healing in northwestern New Spain.

    PubMed

    Kay, M

    1987-01-01

    Northwestern New Spain experienced not only a territorial and a spiritual conquest, but a medical conquest. This medical conquest came from a tradition, established after the conquest of central New Spain, that had fused classical medicine of the Old World with medicine of indigenous groups, in the writings of European doctors and scientists as well as graduates of Mexican colleges. The medical conquest of Sonora was accomplished by laymen, explorers and missionaries who carried the theory of healing resulting from these syncretic processes into the northern lands, adding new materials that they learned from indigenous peoples there. When the Indians were ill with epidemic disease or injuries, they were cared for by missionaries brought up on European domestic medicine. The theory of illness and its cure held by the lay healers became predominantly that of the conquest culture. The conquerers', missionaries' and colonists' interpretations of native plant, animal and mineral remedies that they learned from northwestern native medicine were colored by their own concepts of disease and healing, resulting in an epistemology which continues to guide lay or domestic medicine not only in Sonora but also in the rest of the American Mexican west today.

  5. Acute rheumatic fever in First Nations communities in northwestern Ontario

    PubMed Central

    Gordon, Janet; Kirlew, Mike; Schreiber, Yoko; Saginur, Raphael; Bocking, Natalie; Blakelock, Brittany; Haavaldsrud, Michelle; Kennedy, Christine; Farrell, Terri; Douglas, Lloyd; Kelly, Len

    2015-01-01

    Abstract Objective To document a case series of 8 young First Nations patients diagnosed with acute rheumatic fever (ARF), a preventable disease that resulted in the death of 2 patients, in northwestern Ontario in the context of late diagnosis, overcrowded housing, and inadequate public health response. Design Retrospective case series over an 18-month period. Setting Remote First Nations communities in northwestern Ontario. Participants Eight patients with ARF. Main outcome measures Incidence, mortality, residual rheumatic heart disease, time to diagnosis, barriers to diagnosis and treatment, housing situation of patients, patient demographic characteristics (age, sex), and investigation results. Results The incidence of ARF in this population was 21.3 per 100 000, which is 75 times greater than the overall Canadian estimated incidence. The average patient age was 9.4 years. Most cases developed joint findings, and 5 of the surviving patients had rheumatic heart disease when they received echocardiography. The average time to diagnosis was 88 days. Two 4-year-old children died from ARF. Most patients lived in inadequate and crowded housing. Conclusion This rare disease still exists in remote First Nations communities. These communities demonstrate an incidence equal to that in aboriginal communities in Australia and New Zealand, which have among the highest international incidence of ARF. Primordial prevention, including improved on-reserve housing, is urgently needed. Case detection and ongoing surveillance for primary and secondary prophylaxis requires a well resourced regional strategy. PMID:26759842

  6. Trophic structure of pelagic species in the northwestern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Albo-Puigserver, Marta; Navarro, Joan; Coll, Marta; Layman, Craig A.; Palomera, Isabel

    2016-11-01

    Ecological knowledge of food web interactions within pelagic marine communities is often limited, impairing our capabilities to manage these ecologically and economically important marine fish species. Here we used stable isotope analyses to investigate trophic interactions in the pelagic ecosystem of the northwestern Mediterranean Sea during 2012 and 2013. Our results suggest that European sardine, Sardina pilchardus, and anchovy, Engraulis encrasicolus, are consumers located at relatively low levels of the pelagic food web. Unexpectedly, the round sardinella, Sardinella aurita, appeared to be located at a higher trophic level than the other small pelagic fish species, although previous studies found similarity in their diets. Isotope data suggested that trophic niches of species within the genera Trachurus spp. and Scomber spp., were distinct. Atlantic bonito Sarda sarda, European hake Merluccius merluccius and European squid Loligo vulgaris, appeared to feed at higher trophic levels than other species. Despite some intraspecific seasonal variability for some species, community trophic structure appeared relatively stable through the year. These data provide an important step for developing models of food web dynamics in the northwestern Mediterranean Sea.

  7. Ovine prion protein genotype frequencies in northwestern China.

    PubMed

    Zhao, C-L; Wu, R; Liu, L; Li, F-D; Zhang, X-L; Wang, C; Wang, F; Diao, X-L; Guan, H-W; Wang, X; Zhou, L

    2012-06-21

    Anti-scrapie breeding programs have been initiated to screen for scrapie-resistant sheep based on ovine prion protein gene (PRNP) genotypes at codons 136, 154 and 171 in many countries, especially European Union member states. However, investigation of sheep PRNP genotypes is limited in China, despite the large number of sheep breeds. We analyzed 432 sheep of five different breeds from farms in northwestern China, using PCR-single-strand conformational polymorphism analysis (PCR-SSCP); the corresponding haplotypes of different PRNP alleles were cloned. PRNP allele genotyping was done by amplification refractory mutation system-PCR (ARMS-PCR), according to the haplotype clones of each PRNP allele. The validity of ARMS-PCR was checked by PCR-SSCP. Another 325 unknown PRNP genotypes of other sheep breeds were analyzed according to the established ARMS-PCR. Genotype frequencies of 757 sheep were analyzed with these two methods to evaluate susceptibility to scrapie in northwestern China. Relevant mutations were also detected at other sites. Both methods were effective for ovine PRNP allele genotyping, and the results of the analysis completely coincided. Scrapie-resistant genotypes were found to be uncommon, indicating a high risk for ovine scrapie in northwest China. In addition to codons 136, 154 and 171, we found numerous new mutations; nearly half of them were previously unreported. These sheep populations have a high degree of polymorphism at the PRNP locus.

  8. Data assimilation of Argo profiles in a northwestern Pacific model

    NASA Astrophysics Data System (ADS)

    Wang, Zhaoyi; Storto, Andrea; Pinardi, Nadia; Liu, Guimei; Wang, Hui

    2017-01-01

    Based on a novel estimation of background-error covariances for assimilating Argo profiles, an oceanographic three-dimensional variational (3DVAR) data assimilation scheme was developed for the northwestern Pacific Ocean model (NwPM) for potential use in operational predictions and maritime safety applications. Temperature and salinity data extracted from Argo profiles from January to December 2010 were assimilated into the NwPM. The results show that the average daily temperature (salinity) root mean square error (RMSE) decreased from 0.99 °C (0.10 psu) to 0.62 °C (0.07 psu) in assimilation experiments throughout the northwestern Pacific, which represents a 37.2 % (27.6 %) reduction in the error. The temperature (salinity) RMSE decreased by ˜ 0.60 °C ( ˜ 0.05 psu) for the upper 900 m (1000 m). Sea level, temperature and salinity were in better agreement with in situ and satellite datasets after data assimilation than before. In addition, a 1-month experiment with daily analysis cycles and 5-day forecasts explored the performance of the system in an operational configuration. The results highlighted the positive impact of the 3DVAR initialization at all forecast ranges compared to the non-assimilative experiment. Therefore, the 3DVAR scheme proposed here, coupled to ROMS, shows a good predictive performance and can be used as an assimilation scheme for operational forecasting.

  9. Seismic anisotropy in the continental crust of northwestern Canada

    NASA Astrophysics Data System (ADS)

    Dalton, Colleen A.; Gaherty, James B.

    2013-04-01

    Most studies of the seismic structure of continental crust assume that the wave speeds are isotropic at seismic wavelengths. The ability to measure surface wave propagation speed from the cross-correlation of ambient seismic noise provides new opportunities to image the crust and uppermost mantle. We investigate radial anisotropy in the continental crust of northwestern Canada from group-velocity curves of Love and Rayleigh waves obtained from ambient-noise cross-correlation. We test the null hypothesis that the Love and Rayleigh group-speed curves can be simultaneously fit by an earth model containing isotropic seismic velocities throughout the crust. Group velocity is predicted for 200 000 one-dimensional earth models, which are generated by randomly varying the crustal shear velocity and radial anisotropy within a prescribed range. The goodness-of-fit of the predictions is assessed by comparison with two sets of observed dispersion curves that correspond to two tectonically distinct terranes: the Archean/early Proterozoic craton and the transition from craton to Cordillera. The majority of best-fitting models contain VSH > VSV (4-5 per cent) in the middle crust. The finding that the middle/lower crust is seismically anisotropic across a large swath of northwestern Canada, combined with recent observations of anisotropic crust in much of the western United States, suggests that anisotropy may be ubiquitous in the continental crust.

  10. Early Mesozoic structure and stratigraphy of the northwestern Florida shelf

    SciTech Connect

    Reitz, B.K. )

    1991-03-01

    The pre-Mesozoic basement of the northwestern Florida shelf is composed of attenuated continental crust deformed during the late Triassic and Early Jurassic rifting of the Gulf of Mexico. Two distinct areas with different rift basin orientations are defined on the northwestern Florida shelf. The northeastern set of rifts has axes parallel to the rift basins of the Atlantic margin. The southwestern rift axes are orthogonal to the first set. These two areas are separated by an undisturbed northwest-southwest linear zone previously termed the Bahama fault zone. Margins of a major asymmetric rift basin, north of the Middle Ground arch, parallel the Bahamas fault zone. The asymmetric plan view and degree of crustal extension calculated for this basin suggests the Middle Ground arch formed by a counterclockwise rotation of 16{degree}. The geometries of the Upper Jurassic postrift sediments are related to rift morphology. Louann Salt updip limits are parallel to or coincident with the margins of the rift basins and the salt is thickest over the deepest portions of the rift basins. The distribution of Smackover-Haynesville and Cotton Valley Group sediments is strongly influenced by the underlying rift basins.

  11. An Ancestral Language to Speak with the "Other": Closing down Ideological Spaces of a Language Policy in the Peruvian Andes

    ERIC Educational Resources Information Center

    Zavala, Virginia

    2014-01-01

    Using a multilayered, ethnographic and critical approach to language policy and planning, this article examines a language policy favoring Quechua in Apurímac in the Southern Peruvian Andes, which is being imagined as an integrated community unified by the local language. This study presents a case in which top-down policies open up ideological…

  12. Changes in structure and composition of evergreen forests on an altitudinal gradient in the Venezuelan Guayana shield.

    PubMed

    Hernández, Lionel; Dezzeo, Nelda; Sanoja, Elio; Salazar, Leandro; Castellanos, Hernán

    2012-03-01

    There have been several ecological studies in forests of the Guayana Shield, but so far none had examined the changes in structure and composition of evergreen forests with altitude. This study describes and analyzes the structure, species composition and soil characteristics of forest stands at different altitudinal zones in Southeastern Venezuelan Guayana, in order to explain the patterns and the main factors that determine the structure and composition of evergreen forests along the altitudinal gradient. Inventories of 3 948 big (>10cm DBH) and 1 328 small (5-10cm DBH) woody stems were carried out in eleven plots, ranging from 0.1 to 1.0ha, along a 188km long transect with elevations between 290 and 1 395masl. It has been found that 1) hemiepihytes become more dominant and lianas reduce their dominance with increasing altitude and 2) the forest structure in the study area is size-dependent. Five families and 12 genera represented only 9% of the total number of families and genera, respectively, recorded troughout the gradient, but the two groups of taxa comprised more than 50% of the Importance Value (the sum of the relative density and the relative dominance) of all measured stems. Moreover, the results suggest that low species richness seems to be associated with the dominance of one or few species. Stand-level wood density (WD) of trees decreased significantly with increasing elevation. WD is an indicator of trees'life history strategy. Its decline suggests a change in the functional composition of the forest with increasing altitude. The Canonical Correspondence Analysis (CCA) indicated a distinction of the studied forests on the basis of their altitudinal levels and geographic location, and revealed different ecological responses by the forests, to environmental variables along the altitudinal gradient. The variation in species composition, in terms of basal area among stands, was controlled primarily by elevation and secondarily by rainfall and soil

  13. Infection by Ascaris lumbricoides and bronchial hyper reactivity: an outstanding association in Venezuelan school children from endemic areas.

    PubMed

    Hagel, I; Cabrera, M; Hurtado, M A; Sanchez, P; Puccio, F; Di Prisco, M C; Palenque, M

    2007-09-01

    Asthma and other respiratory diseases have increased in the last years among Venezuelan children from helminthic endemic areas where the infection by Ascaris lumbricoides has been associated to bronchial airway inflammation in parasitized individuals. The aim of this work was to investigate the possible associations between the development of bronchial hyper reactivity and the immune response against A. lumbricoides in urban and rural children. We evaluated 470 school children from rural and urban communities. Pulmonary function tests were performed and >or=20% PC(20) changes were considered as a positive diagnostic of bronchial hyper reactivity. The prevalence and intensity of A. lumbricoides infection was determined by faecal examination. Specific serum IgE levels using a modified ELISA and skin prick tests against A. lumbricoides and the common allergen Dermatophagoides pteronyssinus were done. The number of circulating lymphocyte sub populations was determined by flow cytometry analysis. In rural children, bronchial hyper reactivity was associated with increased specific levels of anti-A. lumbricoides IgE (p<0.0001) and skin test positivity for A. lumbricoides (p<0.0001). The percentage of FEV1 predictive values correlated inversely (p<0.0001) with anti-A. lumbricoides IgE levels. Elevated numbers of circulating CD3+CD4+ and CD20+CD23+ cells were found in rural children with bronchial hyper reactivity compared to their asymptomatic counterparts. They correlated positively with anti-A. lumbricoides IgE levels (p<0.005 and <0.0001, respectively). In contrast, in urban children, bronchial hyper reactivity was associated with elevated anti-D. pteronyssinus IgE levels (p=0. 0089), skin hyper reactivity towards this aero allergen (p=0.003) and to an increase in the number of CD3+CD8+ (p<0.0001). Our results suggest that the IgE response against A. lumbricoides infection may be involved in the development of bronchial hyper reactivity among rural children from endemic

  14. mRNA Capping by Venezuelan Equine Encephalitis Virus nsP1: Functional Characterization and Implications for Antiviral Research

    PubMed Central

    Li, Changqing; Guillén, Jaime; Rabah, Nadia; Blanjoie, Alexandre; Debart, Françoise; Vasseur, Jean-Jacques; Canard, Bruno; Decroly, Etienne

    2015-01-01

    ABSTRACT Alphaviruses are known to possess a unique viral mRNA capping mechanism involving the viral nonstructural protein nsP1. This enzyme harbors methyltransferase (MTase) and nsP1 guanylylation (GT) activities catalyzing the transfer of the methyl group from S-adenosylmethionine (AdoMet) to the N7 position of a GTP molecule followed by the formation of an m7GMP-nsP1 adduct. Subsequent transfer of m7GMP onto the 5′ end of the viral mRNA has not been demonstrated in vitro yet. Here we report the biochemical characterization of Venezuelan equine encephalitis virus (VEEV) nsP1. We have developed enzymatic assays uncoupling the different reactions steps catalyzed by nsP1. The MTase and GT reaction activities were followed using a nonhydrolyzable GTP (GIDP) substrate and an original Western blot assay using anti-m3G/m7G-cap monoclonal antibody, respectively. The GT reaction is stimulated by S-adenosyl-l-homocysteine (Ado-Hcy), the product of the preceding MTase reaction, and metallic ions. The covalent linking between nsP1 and m7GMP involves a phosphamide bond between the nucleotide and a histidine residue. Final guanylyltransfer onto RNA was observed for the first time with an alphavirus nsP1 using a 5′-diphosphate RNA oligonucleotide whose sequence corresponds to the 5′ end of the viral genome. Alanine scanning mutagenesis of residues H37, H45, D63, E118, Y285, D354, R365, N369, and N375 revealed their respective roles in MT and GT reactions. Finally, the inhibitory effects of sinefungin, aurintricarboxylic acid (ATA), and ribavirin triphosphate on MTase and capping reactions were investigated, providing possible avenues for antiviral research. IMPORTANCE Emergence or reemergence of alphaviruses represents a serious health concern, and the elucidation of their replication mechanisms is a prerequisite for the development of specific inhibitors targeting viral enzymes. In particular, alphaviruses are able, through an original reaction sequence, to add to their

  15. Crustal Thickness in Northern Andes Using pP and sS Precursors at Teleseismic Distances

    NASA Astrophysics Data System (ADS)

    Aranda Camacho, N. M.; Assumpcao, M.

    2013-12-01

    The Andean belt is a result of the subduction of the Nazca plate beneath the South American continental plate. It has an extension of 8000 km from Venezuela to Tierra del Fuego. While the crustal-thickness is a well-known property in Southern and Central Andes, it is still poorly known in the Northern Andes (between 10°N and 4° S). The crustal thickness is a very important property to understand the crustal evolution such as in geodynamic models and in modeling wave-propagation in global and regional seismic studies. Due to the high seismic activity at intermediate depths in the Northern Andes, it is possible to use the teleseismic P-wave and S-wave trains to find the crustal-thickness. In this study, we analyze the reflections from the underside of the Moho for intermediate and deep earthquakes in the northern Andes recorded at teleseismic distances (between 40°- 85°), and estimate the crustal-thickness at the bounce points of the pP and sS wave by converting the delay time between the phases pP and pmP and also between sS and smS into crustal thickness. This method can be applied in zones with earthquakes having magnitude larger than 6 for that reason the Northern Andes is a favorable area to develop it. We analyzed five events from the Northern Andes with magnitude larger than 6 and deeper than 100 km. The crustal thickness was calculated using the P wave with the vertical component and the S wave using both transverse SH and radial SV components. We find that the crustal-thickness in this area varied from 27.9 × 2.4 km at (76.48 W, 4.82 N) to 55.7 × 5.2 km at (77.92 W, 2 S). Our results show a crustal-thickness consistent with a compilation made for a larger region that includes our research area, showing residuals between -4 km and 4 km in most of the bounce points . We are getting results in areas that have not been studied previously so it will help to increase the database of crustal-thicknesses for the Northern Andes.

  16. New constraints on the uplift history of the western Andes, north Chile, using cosmogenic He-3 in alluvial boulders

    NASA Astrophysics Data System (ADS)

    Evenstar, Laura; Stuart, Finlay; Hartley, Adrian

    2014-05-01

    To constrain mechanisms responsible for mountain belt growth independent methods for determining accurately the rate and timing of surface uplift are needed. Within the Central Andes paleoelevation proxies are afflicted by either large uncertainties or reliance on assumptions about past climate-elevation histories (Barnes and Ehmer. 2009). This leads to paleoelevation data being unable to distinguish between the two main uplift models of the Andes; gradual uplift of the Andes from the Late Eocene due to crustal shortening/thickening, and rapid uplift in the Late Miocene due to large-scale mantle delamination (Barnes and Ehmer. 2009). Here we present a new paleoelevation tool based on the varying production rate of in situ cosmogenic isotopes with elevation. It can constrain surface uplift histories independently of paleoclimatic fluctuations, making it potentially more accurate than previous methods. Within the Atacama Desert Northern Chile, a stable arid-hyperarid climate has persisted over the last 23 Ma (Dunai et al. 2005). This has lead to exceptionally low erosion rates and high cosmogenic nuclide concentrations within alluvial boulders overlying the Pacific Planation Surface (PPS). In the Aroma Quebrada region, the PPS can be constrained as forming post 13.4 Ma, using underlying volcanics (Evenstar 2007). Alluvial boulders that lie on this PPS have high concentrations of cosmogenic He-3 that suggest deposition soon after surface formation. Comparing concentrations of cosmogenic 3He in the boulders to those calculated for varying uplift histories the timing of the uplift of the western margin of the Andes can be constrained. The models require the Pacific Planation Surface to reach at least 2/3 of its current elevation by 13.4 Ma. These results are not consistent with rapid uplift of the Andes due to mantle delamination in the Late Miocene but support progressive shortening and thickening of continental crust initiating in the Early Miocene or earlier.

  17. Prediction of glacier melt and runoff for a high-altitude headwater catchment in Bolivian Andes

    NASA Astrophysics Data System (ADS)

    Liu, T.; Kinouchi, T.; Mendoza, J.; Asaoka, Y.

    2013-12-01

    In Andes, retreat of tropical glaciers is rapid, thus water resources currently available from glacierized catchments would be changed in its volume and temporal variations due to climate change and glacier shrinkage. Water resources in La Paz and El Alto, Bolivia, strongly depend on the runoff from glacierized headwater catchments in the Cordillera Real, Andes, which is a combined contribution from glacier and snow melts in glacierized areas and surface and subsurface runoff due to snowmelt and rainfall in non-glacierized areas. To predict long-term availability of water resources from glacierized catchments in the Cordillera Real, we developed a semi-distributed conceptual glacio-hydrological model applicable for the partially glacierized catchments in high mountains by considering different phases of precipitation, various runoff components from glacierized and non-glacierized areas, the retarding effect by lakes and wetlands, and the change of glacierized areas based on the area-volume relationship. The model was successfully applied to the Huayna West headwater catchment located in the Cordillera Real, Bolivian Andes, for the period of June 2011 to May 2013, after calibrating by observed meteorological and hydrological conditions. Our results indicate that the glacier melt is enhanced during two transition periods, i.e. from the dry to wet season (October to early December) and the wet to dry season (March to May), while the surface runoff from snowmelt and subsurface runoff are more dominant between the two periods from December to February. It was found that the simulated runoff was highly sensible to spatial and temporal variation of air temperature, and smoothed by the subsurface flow and retarding processes in lakes and wetlands. We predicted the change of glacierized area and runoff until 2050 under different climate scenarios, which indicates that the glacier continues to shrink by 2050 resulting in the areal reduction ranging from 65% to 73% and

  18. What controls millennial-scale denudation rates across the Central Andes?

    NASA Astrophysics Data System (ADS)

    Zeilinger, Gerold; Korup, Oliver; Schlunegger, Fritz; Kober, Florian

    2015-04-01

    Sustainable planning of erosion control measures in the Central Andes requires robust knowledge about natural denudation rates. We explore a large dataset combining new and published 10Be (and 26Al) catchment-wide denudation rates from a swath at 17 to 19° S spanning the Western Cordillera that rises from sea level to 5500 m elevation; the Altiplano at ~4000 m; the Eastern Cordillera with elevations up to 6500 m; the Interandean Zone; the Subandean Zone; and the Chaco Plain at 300 m. The selected catchments span a large spread regarding morphometric and climate properties where mean slope angles range from 1 to 31°, and mean precipitation from 100 to 3900 mm/a. The denudation rates (0.0036 to 1.93 mm/a) are averaged over millennia, and reveal two to three magnitudes difference across the Central Andes. The regional distribution of denudation rates clearly demonstrates a more complex interaction of geomorphological, geological and meteorological parameters with the dominant geomorphological processes. In order to elucidate the key controls on denudation, we use multivariate statistics such as principal component analysis in order to remove potentially redundant predictors of denudation in the studied catchments. These predictors include catchment elevation, topographic relief, hillslope inclination, mean precipitation, tree cover, specific stream power, channel steepness indices, sinuosity, drainage density and hypsometric index that we derived from the SRTM 90 m Digital Elevation Database, the Tropical Rainfall Measuring Mission (TRMM) data, and the Terra MODIS Vegetation Continuous Fields dataset. Additionally, the rock strength index (PLI) was estimated based on geological units. Preliminary results allow distinguishing five different longitudinal domains of denudation on the basis of climatic regime, hillslope steepness, and the degree of accumulated crustal deformation. We find that the pattern of 10Be catchment-wide denudation rates in the Central Andes

  19. The Andes as a peripheral orogen of the breaking-up Pangea

    NASA Astrophysics Data System (ADS)

    Lomize, M. G.

    2008-05-01

    Formation conditions of the peripheral orogen are expressed most fully in the Central Andes, a mountain system almost not yielding in height to the Himalayan-Tibetan system but formed at the margin of ocean without any relations to intercontinental collision. The marine transgression and rejuvenation of subduction in the Early Jurassic during the origination of foldbelt at the margin of Pangea marked the transition to a new supercontinental cycle, and the overall further evolution began and continues now in the frame of the first half of this cycle. The marginal position of this belt above the subduction zone, the rate and orientation of convergence of the lithospheric plates, the age of “absolute” movement of the continental plate, variation in slab velocity, and subduction of heterogeneities of the oceanic crust were the crucial factors that controlled the evolution of the marginal foldbelt. At the stage of initial subsidence (Jurassic-Mid-Cretaceous), during extension of the crust having a moderate thickness (30-35 km), the Andean continental margin comprises the full structural elements of an ensialic island arc that resembled the present-day Sunda system. These conditions changed with the separation and onset of the western drift of the South American continent. Being anchored in the mantle and relatively young, the slab of the Andean subduction zone served as a stop that brought about compression that controlled the subsequent evolution. Due to the contribution of deep magma sources along with marine sediments and products of tectonic erosion removed to a depth, the growth of crust above the subduction zone was favorable for heating of the crust. By the middle Eocene, when compression enhanced owing to the acceleration of subduction, the thermal evolution of the crust had already prepared the transition to the orogenic stage of evolution, i.e., to the progressive viscoplastic shortening and swelling of the mechanically weakened lower crust and the

  20. Zonal management of arsenic contaminated ground water in Northwestern Bangladesh.

    PubMed

    Hill, Jason; Hossain, Faisal; Bagtzoglou, Amvrossios C

    2009-09-01

    This paper used ordinary kriging to spatially map arsenic contamination in shallow aquifers of Northwestern Bangladesh (total area approximately 35,000 km(2)). The Northwestern region was selected because it represents a relatively safer source of large-scale and affordable water supply for the rest of Bangladesh currently faced with extensive arsenic contamination in drinking water (such as the Southern regions). Hence, the work appropriately explored sustainability issues by building upon a previously published study (Hossain et al., 2007; Water Resources Management, vol. 21: 1245-1261) where a more general nation-wide assessment afforded by kriging was identified. The arsenic database for reference comprised the nation-wide survey (of 3534 drinking wells) completed in 1999 by the British Geological Survey (BGS) in collaboration with the Department of Public Health Engineering (DPHE) of Bangladesh. Randomly sampled networks of zones from this reference database were used to develop an empirical variogram and develop maps of zonal arsenic concentration for the Northwestern region. The remaining non-sampled zones from the reference database were used to assess the accuracy of the kriged maps. Two additional criteria were explored: (1) the ability of geostatistical interpolators such as kriging to extrapolate information on spatial structure of arsenic contamination beyond small-scale exploratory domains; (2) the impact of a priori knowledge of anisotropic variability on the effectiveness of geostatistically based management. On the average, the kriging method was found to have a 90% probability of successful prediction of safe zones according to the WHO safe limit of 10ppb while for the Bangladesh safe limit of 50ppb, the safe zone prediction probability was 97%. Compared to the previous study by Hossain et al. (2007) over the rest of the contaminated country side, the probability of successful detection of safe zones in the Northwest is observed to be about 25

  1. Examining a Half Century of Northwestern North American Glacier Behavior

    NASA Astrophysics Data System (ADS)

    Molnia, B. F.; Fahey, M. J.; Friesen, B.; Josberger, E. G.

    2015-12-01

    In 1957, as part of the United States' contribution to the International Geophysical Year (IGY), the American Geographical Society (AGS) initiated a multi-institutional mapping project to produce 1:10,000-scale topographic maps of nine northwestern North American glaciers. The project's goal was to prepare precise maps at large scales of selected small glaciers to form a permanent record of the condition of these glaciers so that at a future date they could be resurveyed and compared. Continued surveys would give the history of wastage and accumulation, and more accurate interpretation of the response of these glaciers to meteorological and other factors. The resulting maps and a descriptive summary brochure were published in 1960 by the American Geographical Society. The USGS Global Fiducials Program (GFP) began to systematically image the same nine glaciers approximately half-century after its IGY mapping. The results of the GFP analyses would permit the types of comparisons that were envisioned by the IGY project. Imagery of each of these nine glaciers has been collected from multiple sources, including Next View licensed commercial imagery, vertical and oblique aerial photography, Landsat, and US National Imagery Systems. Exploitation of the imagery has resulted in the production of new 21st century maps that can be compared and contrasted with the vintage AGS map set. Comparison will permit the calculation of a number of parameters which will provide a direct insight into the changes that northwestern North American glaciers have been experiencing during the past half century. Specifically, these comparisons will permit the calculation of changes in glacier length, area, thickness, and volume; computation of rates of glacier advance and/or retreat, rates of glacier thickening and/or thinning, and rates of volume change; production of digital elevation models (DEMs); and generation of velocity fields from crevasse migration. The subsequent re-mapping and

  2. Andes Virus Antigens Are Shed in Urine of Patients with Acute Hantavirus Cardiopulmonary Syndrome▿ ‡

    PubMed Central

    Godoy, Paula; Marsac, Delphine; Stefas, Elias; Ferrer, Pablo; Tischler, Nicole D.; Pino, Karla; Ramdohr, Pablo; Vial, Pablo; Valenzuela, Pablo D. T.; Ferrés, Marcela; Veas, Francisco; López-Lastra, Marcelo

    2009-01-01

    Hantavirus cardiopulmonary syndrome (HCPS) is a highly pathogenic emerging disease (40% case fatality rate) caused by New World hantaviruses. Hantavirus infections are transmitted to humans mainly by inhalation of virus-contaminated aerosol particles of rodent excreta and secretions. At present, there are no antiviral drugs or immunotherapeutic agents available for the treatment of hantaviral infection, and the survival rates for infected patients hinge largely on early virus recognition and hospital admission and aggressive pulmonary and hemodynamic support. In this study, we show that Andes virus (ANDV) interacts with human apolipoprotein H (ApoH) and that ApoH-coated magnetic beads or ApoH-coated enzyme-linked immunosorbent assay plates can be used to capture and concentrate the virus from complex biological mixtures, such as serum and urine, allowing it to be detected by both immunological and molecular approaches. In addition, we report that ANDV-antigens and infectious virus are shed in urine of HCPS patients. PMID:19279096

  3. The Flying Telescope: How to Reach Remote Areas in the Colombian Andes for Astronomy Outreach

    NASA Astrophysics Data System (ADS)

    Seidel, M. K.; Buelhoff, K.

    2016-12-01

    The project Cielo y Tierra, Spanish for Sky and Earth, was undertaken in order to bring astronomy and ecology to remote villages throughout Colombia using sustainable transport. This transport included three horses and two paragliders. The innovative approach of the expedition helped to keep an extremely low budget whilst making it possible to cross the Colombian Andes from northeast to southwest. This article will show how projects like these can succeed, the need for this kind of project, and the possible impact, with this project reaching more than 1500 people. We hope to encourage others not to be afraid of going into countries like Colombia on a low-budget educational expedition. The success of this project shows that outreach and education projects are possible in these remote areas where little or no governmental or other support reaches.

  4. Mapping advanced argillic alteration zones with ASTER and Hyperion data in the Andes Mountains of Peru

    NASA Astrophysics Data System (ADS)

    Ramos, Yuddy; Goïta, Kalifa; Péloquin, Stéphane

    2016-04-01

    This study evaluates Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Hyperion hyperspectral sensor datasets to detect advanced argillic minerals. The spectral signatures of some alteration clay minerals, such as dickite and alunite, have similar absorption features; thus separating them using multispectral satellite images is a complex challenge. However, Hyperion with its fine spectral bands has potential for good separability of features. The Spectral Angle Mapper algorithm was used in this study to map three advanced argillic alteration minerals (alunite, kaolinite, and dickite) in a known alteration zone in the Peruvian Andes. The results from ASTER and Hyperion were analyzed, compared, and validated using a Portable Infrared Mineral Analyzer field spectrometer. The alterations corresponding to kaolinite and alunite were detected with both ASTER and Hyperion (80% to 84% accuracy). However, the dickite mineral was identified only with Hyperion (82% accuracy).

  5. The major cellular sterol regulatory pathway is required for Andes virus infection.

    PubMed

    Petersen, Josiah; Drake, Mary Jane; Bruce, Emily A; Riblett, Amber M; Didigu, Chukwuka A; Wilen, Craig B; Malani, Nirav; Male, Frances; Lee, Fang-Hua; Bushman, Frederic D; Cherry, Sara; Doms, Robert W; Bates, Paul; Briley, Kenneth

    2014-02-01

    The Bunyaviridae comprise a large family of RNA viruses with worldwide distribution and includes the pathogenic New World hantavirus, Andes virus (ANDV). Host factors needed for hantavirus entry remain largely enigmatic and therapeutics are unavailable. To identify cellular requirements for ANDV infection, we performed two parallel genetic screens. Analysis of a large library of insertionally mutagenized human haploid cells and a siRNA genomic screen converged on components (SREBP-2, SCAP, S1P and S2P) of the sterol regulatory pathway as critically important for infection by ANDV. The significance of this pathway was confirmed using functionally deficient cells, TALEN-mediated gene disruption, RNA interference and pharmacologic inhibition. Disruption of sterol regulatory complex function impaired ANDV internalization without affecting virus binding. Pharmacologic manipulation of cholesterol levels demonstrated that ANDV entry is sensitive to changes in cellular cholesterol and raises the possibility that clinically approved regulators of sterol synthesis may prove useful for combating ANDV infection.

  6. Multiethnicity, pluralism, and migration in the south central Andes: An alternate path to state expansion

    PubMed Central

    Goldstein, Paul S.

    2015-01-01

    The south central Andes is known as a region of enduring multiethnic diversity, yet it is also the cradle of one the South America’s first successful expansive-state societies. Social structures that encouraged the maintenance of separate identities among coexistent ethnic groups may explain this apparent contradiction. Although the early expansion of the Tiwanaku state (A.D. 600–1000) is often interpreted according to a centralized model derived from Old World precedents, recent archaeological research suggests a reappraisal of the socio-political organization of Tiwanaku civilization, both for the diversity of social entities within its core region and for the multiple agencies behind its wider program of agropastoral colonization. Tiwanaku’s sociopolitical pluralism in both its homeland and colonies tempers some of archaeology’s global assumptions about the predominant role of centralized institutions in archaic states. PMID:26195732

  7. Landsat Thematic Mapper observations of debris avalanche deposits in the Central Andes

    NASA Technical Reports Server (NTRS)

    Francis, P. W.; Wells, G. L.

    1988-01-01

    Remote sensing with the Landsat Thematic Mapper of debris avalanche deposits in the Central Andes between 18 and 27 deg S revealed, for the first time, the presence of 28 breached volcanic cones and 11 major volcanic debris avalanche deposits, several of which cover areas in excess of 100 sq km. It is concluded that such avalanche deposits are normal products of the evolution of large composite volcanoes, comparable with lava and pyroclastic flow deposits. A statistical survey of 578 composite volcanoes in the same area indicated that a majority of cones which achieve edifice heights between 2000 and 3000 m may undergo sector collapse. The paper describes morphological criteria for identifying breached composite cones and volcanic debris avalanches using orbital images.

  8. Hydrogeochemistry Characterization of Hot Springs Located in The Andes of Ecuador

    NASA Astrophysics Data System (ADS)

    Vinicio Carrera-Villacrés, David; Hidalgo-Hidalgo, Alexander; Guevara-García, Paulina; Vivero-Balarezo, María; Delgado-Rodríguez, Vicente

    2016-10-01

    The formation of several sources of hot springs in the Andes from Ecuador is the result of an intense volcanic activity due to the subduction of the Nazca oceanic plate under the South American continental plate. The aim of this study was to describe the hydrogeochemistry water geothermal origin, its chemical classification and relationship with the complex geology of Ecuador, using different hydro chemical diagrams (Stiff, Piper and Schoeller-Berkaloff). Geothermal waters can be divided into two groups. The first group, associated with an extinct volcanic activity produced in the Cenozoic, represents the Na+-Cl- type. The second group is associated with a young Quaternary volcanic activity and its types of water are Mg2+-HCO3-, Na+-HCO3-, Na+-SO42-, Mg2+-SO42-.

  9. Contrasting response of glacierized catchments in the Central Himalaya and the Central Andes to climate change

    NASA Astrophysics Data System (ADS)

    Ragettli, Silvan; Pellicciotti, Francesca; Immerzeel, Walter

    2015-04-01

    The Andes of South America and the Himalaya in high-mountain Asia are two regions where advanced simulation models are of vital importance to anticipate the impacts of climate change on water resources. The two mountain systems hold the largest ice masses outside the polar regions. Major rivers originate here and downstream regions are densely populated. In the long run, glacier recession generates concerns about the sustainability of summer runoff. This study benefits from recent efforts of carefully planned short-term field experiments in two headwater catchments in the Central Andes of Chile and in the Central Himalaya in Nepal. The two study catchments contrast in terms of their climate and in the characteristics of their glaciers. A systematic approach is developed, built upon the available local data, to reduce the predictive uncertainty of a state-of-the-art glacio-hydrological model used for the projection of 21st century glacier changes and catchment runoff. The in-situ data are used for model development and step-wise, multivariate parameter calibration. Catchment runoff and remotely sensed MODIS and Landsat snow cover are used for model validation. The glacio-hydrological model simulates the water cycle with a high temporal (hourly time steps) and spatial (100 m grid cells) resolution and accounts for processes typical of both regions like glacier melt under debris cover or mass redistribution through avalanching. Future projections are based on the outputs of twelve stochastically downscaled global climate models for two emission scenarios (RCP 4.5 and RCP 8.5). This is one of the first truly intercomparative modeling studies at the catchment scale across mountain regions of the world to assess and compare future changes in glaciers and snow cover and associated impacts on streamflow production. Both catchments will experience significant glacier mass loss throughout the twenty-first century. However, the trajectories of simulated future runoff and

  10. Novel Strain of Andes Virus Associated with Fatal Human Infection, Central Bolivia

    PubMed Central

    Cruz, Cristhopher D.; Vallejo, Efrain; Agudo, Roberto; Vargas, Jorge; Blazes, David L.; Guevara, Carolina; Laguna-Torres, V. Alberto; Halsey, Eric S.; Kochel, Tadeusz J.

    2012-01-01

    To better describe the genetic diversity of hantaviruses associated with human illness in South America, we screened blood samples from febrile patients in Chapare Province in central Bolivia during 2008–2009 for recent hantavirus infection. Hantavirus RNA was detected in 3 patients, including 1 who died. Partial RNA sequences of small and medium segments from the 3 patients were most closely related to Andes virus lineages but distinct (<90% nt identity) from reported strains. A survey for IgG against hantaviruses among residents of Chapare Province indicated that 12.2% of the population had past exposure to >1 hantaviruses; the highest prevalence was among agricultural workers. Because of the high level of human exposure to hantavirus strains and the severity of resulting disease, additional studies are warranted to determine the reservoirs, ecologic range, and public health effect of this novel strain of hantavirus. PMID:22515983

  11. Molecular method for the detection of Andes hantavirus infection: validation for clinical diagnostics

    PubMed Central

    Vial, Cecilia; Martinez-Valdebenito, Constanza; Rios, Susana; Martinez, Jessica; Vial, Pablo; Ferres, Marcela; Rivera, Juan Carlos; Perez, Ruth; Valdivieso, Francisca

    2016-01-01

    Hantavirus Cardiopulmonary Syndrome is a severe disease caused by exposure to New World hantaviruses. Early diagnosis is difficult due to the lack of specific initial symptoms. Anti-hantavirus antibodies are usually negative until late in the febrile prodrome or the beginning of cardiopulmonary phase while Andes hantavirus (ANDV) RNA genome can be detected before symptoms onset. We analyzed the effectiveness of RTqPCR as a diagnostic tool detecting ANDV-Sout genome in peripheral blood cells from 78 confirmed hantavirus patients and 166 negative controls. Our results indicate that RTqPCR had a low detection limit (~10 copies), with a specificity of 100% and a sensitivity of 94.9%. This suggests the potential for establishing RT-qPCR as the assay of choice for early diagnosis, promoting early effective care of patients and improve other important aspects of ANDV infection management, such as compliance of biosafety recommendations for health personnel in order to avoid nosocomial transmission. PMID:26508102

  12. Black carbon and other light-absorbing impurities in the Andes of Northern Chile

    NASA Astrophysics Data System (ADS)

    Rowe, P. M.; Cordero, R.; Warren, S. G.; Pankow, A.; Jorquera, J.; Schrempf, M.; Doherty, S. J.; Cabellero, M.; Carrasco, J. F.; Neshyba, S.

    2015-12-01

    Black carbon (BC) and other light-absorbing impurities in snow absorb solar radiation and thus have the potential to accelerate glacial retreat and snowmelt. In Chile, glaciers and seasonal snow are important sources of water for irrigation and domestic uses. In July 2015 (Austral winter) we sampled snow in the western Andes in a north-south transect of Chile from 18 S to 34 S. Most of the sampled snow had fallen during a single synoptic event, during 11-13 July. The snow was melted and passed through 0.4 micrometer nuclepore filters. Preliminary estimates indicate that (1) the ratio of BC to dust in snow increases going south from Northern to Central Chile, and (2) in snow sampled during the two weeks following the snowstorm, the impurities were concentrated in the upper 5 cm of snow, indicating that the surface layer became polluted over time by dry deposition.

  13. Multiethnicity, pluralism, and migration in the south central Andes: An alternate path to state expansion.

    PubMed

    Goldstein, Paul S

    2015-07-28

    The south central Andes is known as a region of enduring multiethnic diversity, yet it is also the cradle of one the South America's first successful expansive-state societies. Social structures that encouraged the maintenance of separate identities among coexistent ethnic groups may explain this apparent contradiction. Although the early expansion of the Tiwanaku state (A.D. 600-1000) is often interpreted according to a centralized model derived from Old World precedents, recent archaeological research suggests a reappraisal of the socio-political organization of Tiwanaku civilization, both for the diversity of social entities within its core region and for the multiple agencies behind its wider program of agropastoral colonization. Tiwanaku's sociopolitical pluralism in both its homeland and colonies tempers some of archaeology's global assumptions about the predominant role of centralized institutions in archaic states.

  14. Controls on continental strain partitioning above an oblique subduction zone, Northern Andes

    NASA Astrophysics Data System (ADS)

    Schütt, Jorina M.; Whipp, David M., Jr.

    2016-04-01

    Strain partitioning is a common process at obliquely convergent plate margins dividing oblique convergence into margin-normal slip on the plate-bounding fault and horizontal shearing on a strike-slip system parallel to the subduction margin. In subduction zones, strain partitioning in the upper continental plate is mainly controlled by the shear forces acting on the plate interface and the strength of the continental crust. The plate interface forces are influenced by the subducting plate dip angle and the obliquity angle between the normal to the plate margin and the convergence velocity vector, and the crustal strength of the continent is strongly affected by the presence or absence of a volcanic arc, with the presence of the volcanic arcs being common at steep subduction zones. Along the ˜7000 km western margin of South America the convergence obliquity, subduction dip angles and presence of a volcanic arc all vary, but strain partitioning is only observed along parts of it. This raises the questions, to what extent do subduction zone characteristics control strain partitioning in the overriding continental plate, and which factors have the largest influence? We address these questions using lithospheric-scale 3D numerical geodynamic experiments to investigate the influence of subduction dip angle, convergence obliquity, and weaknesses in the crust owing to the volcanic arc on strain partitioning behavior. We base the model design on the Northern Volcanic Zone of the Andes (5° N - 2° S), characterized by steep subduction (˜ 35°), a convergence obliquity between 31° -45° and extensive arc volcanism, and where strain partitioning is observed. The numerical modelling software (DOUAR) solves the Stokes flow and heat transfer equations for a viscous-plastic creeping flow to calculate velocity fields, thermal evolution, rock uplift and strain rates in a 1600 km x 1600 km box with depth 160 km. Subduction geometry and material properties are based on a

  15. Two new species of Salamanders, Genus Bolitoglossa (Amphibia: Plethodontidae), from the Eastern Colombian Andes.

    PubMed

    Acevedo, Aldemar A; Wake, David B; Márquez, Roberto; Silva, Karen; Franco, Rosmery; Amézquita, Adolfo

    2013-01-25

    The salamander fauna of Colombia is very poorly known, probably because most research efforts have been devoted to anurans during the last two decades. Here, we describe two new species of the genus Bolitoglossa (Eladinea) from the eastern flank of the Eastern Colombian Andes (Cordillera Oriental), near the border with Venezuela. Bolitoglossa tamaense sp. nov. is distributed between 2000 to 2700 m.a.s.l. and Bolitoglossa leandrae sp. nov. is distributed in the low-lands at about 600 m. The new species are diagnosed by a combination of molecular (16S rRNA sequences), coloration, body size, and morphometric (number of maxillary and vomerine teeth and differences in foot webbing) characters. Both species face threats such as chytridiomycosis infections and habitat fragmentation that have already affected other sala-manders in the country. Thus, intensive field and museum work is needed to better document and perhaps protect the local salamander diversity.

  16. Terrane-boundary reactivation: A control on the evolution of the Northern Andes

    NASA Astrophysics Data System (ADS)

    Litherland, M.; Aspden, J. A.

    1992-01-01

    The Andes of northern Ecuador and southern Colombia comprise two post-Oligocene cordilleras, each with its Plio-Pleistocene volcanic chain separated by the fault-bounded, inter-Andean depression or graben. Along the eastern Peltetec-Romeral fault occur Upper Jurassic ophiolitic rocks marking an ancient suture between the allochthonous Chaucah terrane in the west and the South American plate. Along the western Pujilí-Cauca fault are Upper Cretaceous-lower Eocene ophiolites marking the accretion of the Cretaceous-Eocene Westner Cordillera. Post-Oligocne reactivation of these terane boundaries accounts for the origin of the cordilleras and graben and helps to explain the location of the double chain of Plio-Pleistocene volcanic centers. A caldera-graben model is suggested.

  17. Sinking velocity of particulate radiocesium in the northwestern North Pacific

    NASA Astrophysics Data System (ADS)

    Honda, Makio C.; Kawakami, Hajime

    2014-06-01

    Sinking particles (SP) were collected by time series sediment traps at two depths in the northwestern Pacific before and after the Fukushima Daiichi Nuclear Power Plant accident, and accident-derived particulate radiocesium was measured. Radiocesium (137Cs) was first detected at 500 m (4810 m) about 2 weeks (1 month) after the accident. 137Cs of SP collected over 1 year revealed that the time lag between two depths was larger than that for the first 137Cs detection (about 2 weeks). We estimated the transient sinking velocity (SV) from the cumulative temporal 137Cs flux and the time lags at the two depths. Although the SV of SP collected in very early period was large, the estimated SV of most particulate 137Cs (about 80%) was about 50 m d-1. Based on comparison of 137Cs concentration in total SP with that in SP without organic materials, we suspect that most of the 137Cs was likely incorporated into aluminosilicates.

  18. Water resources of the White Earth Indian Reservation, northwestern Minnesota

    USGS Publications Warehouse

    Ruhl, J.F.

    1989-01-01

    Surface water also is a calcium magnesium bicarbonate type. Lake waters are hard and alkaline and are mesotrophic to eutrophic in productivity. Quality of the lake and stream water is suitable for native forms of freshwater biota, although the concentration of total recoverable mercury exceeds the 0.012 micrograms per liter maximum contaminant level; that level, established by USEPA for the organic form of dissolved mercury, is intended to protect against chronic effects on freshwater life. Available information, however, indicates that the amount of mercury in edible tissue from fish in alkaline lakes of northwestern Minnesota is within safe limits. The concentrations of phosphorus and nitrate in the streams are below levels that indicate pollution problems.

  19. Ankylosaur Remains from the Early Cretaceous (Valanginian) of Northwestern Germany

    PubMed Central

    Sachs, Sven; Hornung, Jahn J.

    2013-01-01

    A fragmentary cervico-pectoral lateral spine and partial humerus of an ankylosaur from the Early Cretaceous (early Valanginian) of Gronau in Westfalen, northwestern Germany, are described. The spine shows closest morphological similarities to the characteristic cervical and pectoral spines of Hylaeosaurus armatus from the late Valanginian of England. An extensive comparison of distal humeri among thyreophoran dinosaurs supports systematic differences in the morphology of the distal condyli between Ankylosauria and Stegosauria and a referral of the Gronau specimen to the former. The humerus fragment indicates a rather small individual, probably in the size range of H. armatus, and both specimens are determined herein as ?Hylaeosaurus sp.. A short overview of other purported ankylosaur material from the Berriasian-Valanginian of northwest Germany shows that, aside from the material described herein, only tracks can be attributed to this clade with confidence at present. PMID:23560099

  20. Floods of January 15-17, 1974, in Northwestern Montana

    USGS Publications Warehouse

    Johnson, M.V.; Omang, R.J.

    1974-01-01

    Introduction Rain and snowmelt caused several streams in northwestern Montana to flood during January 15-17, 1974. The flooding was caused by a major rainstorm that extended from Montana through Idaho and Washington. The most damage occurred in the Kootenai River drainage, centering around the town of Libby. Also unusually high flows occurred on some streams in the Clark Fork basin. Throughout the area, ice jams contributed to much of the overbank flooding. Both the towns of Troy and Libby were partly flooded, but damage was greatest in and near Libby. Flood damage was estimated to be $4.9 million. No flood fatalities were listed. Most of the smaller streams equaled or exceeded a 50-year flood. A summary of flood stages and discharges for 24 sites in the Kootenai River drainage and 8 sites in the Clark Fork drainage is tabulated. A map shows the extent of flooding in the Libby area. (Woodard-USGS)

  1. Occurrence of Trichinella spp. in wild animals in northwestern Libya.

    PubMed

    Hosni, M M; Maghrbi, A A El; Ganghish, K S

    2013-01-01

    The present study determined the occurrence of Trichinella spp. in captured and some perished wildlife animals which included 70 hedgehogs, 19 red foxes, 13 common jackals and 8 crested porcupines in northwestern Libya. Muscle samples of these animals were examined by trichinoscopy. Trichinella larvae were detected only in 4 (5.7%) of the hedgehogs (Erinaceus algirus) and 2 (10.5%) of the red foxes (Vulpes vulpes). Larvae were found in the muscles of the diaphragm, abdomen, tongue, forelimb, hindlimb and intercostal muscles. Examination of tissue sections revealed the presence of numerous cysts within the muscle fibers containing one or more coiled or elongated larvae. Inflammatory cell infiltration was observed around the cysts especially at their poles. Results indicated the importance of wild animals as reservoirs of Trichinella larvae and their role in the transmission of the disease to other wild and domestic animals as well as humans.

  2. The use of photovoltaics for rural electrification in northwestern China

    SciTech Connect

    Wallace, W.L.; Li Jingming; Gao Shangbin

    1998-09-01

    The use of renewable energy technologies in China is becoming increasingly important to meet the needs of a large rural population. Solar and wind renewable resources in particular are available in regions of China that at present have no access to conventional grid power. Two regions in China that have an acute lack of electricity are a large region in northern and western China and the coastal island region of China. These regions have attracted the attention of the Chinese government in terms of increasing the quality of life and standard of living conditions of the rural population. These regions have also attracted the attention of domestic Chinese companies and of international companies, governments, and multilateral development organizations as a potential market for renewable energy rural electrification systems. This paper focuses on the bilateral cooperation between the US Department of Energy and China in providing assistance for the use of renewable technologies for rural electrification in northwestern China.

  3. Geophysical interpretations of the Libby thrust belt, northwestern Montana

    USGS Publications Warehouse

    Kleinkopf, M. Dean; with sections by Harrison, Jack Edward; Stanley, W.D.

    1997-01-01

    Interpretations of gravity and aeromagnetic anomaly data, supplemented by results from two seismic reflection profiles and five magnetotelluric soundings, were used to study buried structure and lithology of the Libby thrust belt of northwestern Montana. The gravity anomaly data show a marked correlation with major structures. The Purcell anticlinorium and the Sylvanite anticline are very likely cored by stacks of thrust slices of dense crystalline basement rocks that account for the large gravity highs across these two structures. Gravity anomaly data for the Cabinet Mountains Wilderness show a string of four broad highs. The principal magnetic anomaly sources are igneous intrusive rocks, major fault zones, and magnetite-bearing sedimentary rocks of the Ravalli Group. The most important magnetic anomalies in the principal study area are five distinct positive anomalies associated with Cretaceous or younger cupolas and stocks.

  4. Hantavirus infection in humans and rodents, northwestern Argentina.

    PubMed

    Pini, Noemi; Levis, Silvana; Calderón, Gladys; Ramirez, Josefina; Bravo, Daniel; Lozano, Elena; Ripoll, Carlos; St Jeor, Stephen; Ksiazek, Thomas G; Barquez, Ruben M; Enria, Delia

    2003-09-01

    We initiated a study to elucidate the ecology and epidemiology of hantavirus infections in northern Argentina. The northwestern hantavirus pulmonary syndrome (HPS)-endemic area of Argentina comprises Salta and Jujuy Provinces. Between 1997 and 2000, 30 HPS cases were diagnosed in Jujuy Province (population 512,329). Most patients had a mild clinical course, and the death rate (13.3%) was low. We performed a serologic and epidemiologic survey in residents of the area, in conjunction with a serologic study in rodents. The prevalence of hantavirus antibodies in the general human population was 6.5%, one of the highest reported in the literature. No evidence of interhuman transmission was found, and the high prevalence of hantavirus antibody seemed to be associated with the high infestation of rodents detected in domestic and peridomestic habitats.

  5. Northwestern Pacific typhoon intensity controlled by changes in ocean temperatures

    PubMed Central

    Mei, Wei; Xie, Shang-Ping; Primeau, François; McWilliams, James C.; Pasquero, Claudia

    2015-01-01

    Dominant climatic factors controlling the lifetime peak intensity of typhoons are determined from six decades of Pacific typhoon data. We find that upper ocean temperatures in the low-latitude northwestern Pacific (LLNWP) and sea surface temperatures in the central equatorial Pacific control the seasonal average lifetime peak intensity by setting the rate and duration of typhoon intensification, respectively. An anomalously strong LLNWP upper ocean warming has favored increased intensification rates and led to unprecedentedly high average typhoon intensity during the recent global warming hiatus period, despite a reduction in intensification duration tied to the central equatorial Pacific surface cooling. Continued LLNWP upper ocean warming as predicted under a moderate [that is, Representative Concentration Pathway (RCP) 4.5] climate change scenario is expected to further increase the average typhoon intensity by an additional 14% by 2100. PMID:26601179

  6. Northwestern Pacific typhoon intensity controlled by changes in ocean temperatures.

    PubMed

    Mei, Wei; Xie, Shang-Ping; Primeau, François; McWilliams, James C; Pasquero, Claudia

    2015-05-01

    Dominant climatic factors controlling the lifetime peak intensity of typhoons are determined from six decades of Pacific typhoon data. We find that upper ocean temperatures in the low-latitude northwestern Pacific (LLNWP) and sea surface temperatures in the central equatorial Pacific control the seasonal average lifetime peak intensity by setting the rate and duration of typhoon intensification, respectively. An anomalously strong LLNWP upper ocean warming has favored increased intensification rates and led to unprecedentedly high average typhoon intensity during the recent global warming hiatus period, despite a reduction in intensification duration tied to the central equatorial Pacific surface cooling. Continued LLNWP upper ocean warming as predicted under a moderate [that is, Representative Concentration Pathway (RCP) 4.5] climate change scenario is expected to further increase the average typhoon intensity by an additional 14% by 2100.

  7. Development of the Gran Desierto sand sea, northwestern Mexico

    NASA Astrophysics Data System (ADS)

    Blount, Grady; Lancaster, Nicholas

    1990-08-01

    Three major eolian sand populations can be recognized in the Gran Desierto sand sea of northwestern Mexico by using spectral data from the Landsat thematic mapper in conjunction with textural and mineralogical studies of surface sands. Each sand population has distinct textural, mineralogic, and spectral properties that can be related to sand-dune morphology and position with reference to source areas and transport paths of the sands. The oldest eolian sediment in the sand sea was derived from the early to middle Pleistocene Colorado River that flowed through the area of the western Gran Desierto. Subsequent inputs of eolian sands came from the area of the present Colorado River valley and the coast south of the sand sea. The spatial and temporal pattern of eolian deposition in the region has been controlled by Quaternary tectonic and climatic changes, resulting in the episodic input and deposition of sand.

  8. Intoxication of nontarget wildlife with rodenticides in northwestern Kansas.

    PubMed

    Ruder, Mark G; Poppenga, Robert H; Bryan, John A; Bain, Matt; Pitman, Jim; Keel, M Kevin

    2011-01-01

    The perception of prairie dogs (Cynomys spp.) both as a nuisance species and a keystone species presents a significant challenge to land, livestock, and wildlife managers. Anticoagulant and nonanticoagulant rodenticides are commonly employed to control prairie dog populations throughout their range. Chlorophacinone, and to a lesser extent zinc phosphide, are widely used in northwestern Kansas for controlling black-tailed prairie dog (Cynomys ludovicianus) populations. Although zinc phosphide poisoning of gallinaceous birds is not uncommon, there are few published accounts of nontarget chlorophacinone poisoning of wildlife. We report three mortality events involving nontarget rodenticide poisoning in several species, including wild turkeys (Meleagris gallopavo), a raccoon (Procyon lotor), and an American badger (Taxidea taxus). This includes the first documentation of chlorophacinone intoxication in wild turkeys and an American badger in the literature. The extent of nontarget poisoning in this area is currently unknown and warrants further investigation.

  9. Land and federal mineral ownership coverage for northwestern Colorado

    USGS Publications Warehouse

    Biewick, L.H.; Mercier, T.J.; Levitt, Pam; Deikman, Doug; Vlahos, Bob

    1999-01-01

    This Arc/Info coverage contains land status and Federal mineral ownership for approximately 26,800 square miles in northwestern Colorado. The polygon coverage (which is also provided here as a shapefile) contains two attributes of ownership information for each polygon. One attribute indicates where the surface is State owned, privately owned, or, if Federally owned, which Federal agency manages the land surface. The other attribute indicates which minerals, if any, are owned by the Federal govenment. This coverage is based on land status and Federal mineral ownership data compiled by the U.S. Geological Survey (USGS) and three Colorado State Bureau of Land Management (BLM) former district offices at a scale of 1:24,000. This coverage was compiled primarily to serve the USGS National Oil and Gas Resource Assessment Project in the Uinta-Piceance Basin Province and the USGS National Coal Resource Assessment Project in the Colorado Plateau.

  10. Hantavirus Infection in Humans and Rodents, Northwestern Argentina

    PubMed Central

    Levis, Silvana; Calderón, Gladys; Ramirez, Josefina; Bravo, Daniel; Lozano, Elena; Ripoll, Carlos; St. Jeor, Stephen; Ksiazek, Thomas G.; Barquez, Ruben M.; Enria, Delia

    2003-01-01

    We initiated a study to elucidate the ecology and epidemiology of hantavirus infections in northern Argentina. The northwestern hantavirus pulmonary syndrome (HPS)–endemic area of Argentina comprises Salta and Jujuy Provinces. Between 1997 and 2000, 30 HPS cases were diagnosed in Jujuy Province (population 512,329). Most patients had a mild clinical course, and the death rate (13.3%) was low. We performed a serologic and epidemiologic survey in residents of the area, in conjunction with a serologic study in rodents. The prevalence of hantavirus antibodies in the general human population was 6.5%, one of the highest reported in the literature. No evidence of interhuman transmission was found, and the high prevalence of hantavirus antibody seemed to be associated with the high infestation of rodents detected in domestic and peridomestic habitats. PMID:14519242

  11. Comparison of the immunological responses and efficacy of gamma-irradiated V3526 vaccine formulations against subcutaneous and aerosol challenge with Venezuelan equine encephalitis virus subtype IAB.

    PubMed

    Martin, Shannon S; Bakken, Russell R; Lind, Cathleen M; Garcia, Patricia; Jenkins, Erin; Glass, Pamela J; Parker, Michael D; Hart, Mary Kate; Fine, Donald L

    2010-01-22

    We recently developed a gamma-irradiation method to inactivate V3526, a live-attenuated Venezuelan equine encephalitis virus (VEEV) vaccine candidate. Dosage and schedule studies were conducted to evaluate the immunogenicity and efficacy of gamma-irradiated V3526 (gV3526). Subcutaneous (SC) and low dosage intramuscular (IM) administration of gV3526 were highly effective in protecting mice against a SC challenge with VEEV IA/B Trinidad Donkey strain, but not against an equivalent aerosol challenge. More robust immune responses and increased protective efficacy were noted when the IM dosage of gV3526 was increased. IM administration of gV3526 formulated with either CpG or CpG plus Alhydrogel further augmented the immune response in mice and resulted in 100% protection against aerosol challenge.

  12. Live, Attenuated Venezuelan Equine Encephalitis Virus Vaccine (TC83) Causes Persistent Brain Infection in Mice with Non-functional αβ T-Cells

    PubMed Central

    Taylor, Katherine; Kolokoltsova, Olga; Ronca, Shannon E.; Estes, Mark; Paessler, Slobodan

    2017-01-01

    Intranasal infection with vaccine strain of Venezuelan equine encephalitis virus (TC83) caused persistent viral infection in the brains of mice without functional αβ T-cells (αβ-TCR -/-). Remarkably, viral kinetics, host response gene transcripts and symptomatic disease are similar between αβ-TCR -/- and wild-type C57BL/6 (WT) mice during acute phase of infection [0–13 days post-infection (dpi)]. While WT mice clear infectious virus in the brain by 13 dpi, αβ-TCR -/- maintain infectious virus in the brain to 92 dpi. Persistent brain infection in αβ-TCR -/- correlated with inflammatory infiltrates and elevated cytokine protein levels in the brain at later time points. Persistent brain infection of αβ-TCR -/- mice provides a novel model to study prolonged alphaviral infection as well as the effects and biomarkers of long-term viral inflammation in the brain. PMID:28184218

  13. Isotopic evidence of pollutant lead sources in Northwestern France

    NASA Astrophysics Data System (ADS)

    Véron, Alain; Flament, Pascal; Bertho, Marie Laure; Alleman, Laurent; Flegal, Russell; Hamelin, Bruno

    Ratios of stable lead isotopes ( 204Pb, 206Pb, 207Pb, 208Pb) are used to characterize both spatial and temporal variations in anthropogenic emissions of industrial lead aerosols to the atmosphere of northwestern France. Differences in isotopic compositions of aerosols collected from a rural area (Wimereux) in the Nord-Pas de Calais region along the English Channel in 1982-1983 ( 206Pb/ 207Pb=1.108±0.005) and 1994 ( 206Pb/ 207Pb=1.148±0.003) are paralleled by similar variations in urban aerosols within France during the same period (e.g., 206Pb/ 207Pb=1.115±0.008 from 1981-1989 and 1.143±0.006 from 1992-1995). These results correlate well with recent findings in the Mediterranean basin (Alleman, 1997) where this radiogenicity increase is clearly associated with industrial sources other than leaded gasoline that has remained relatively constant during its phasing out ( 206Pb/ 207Pb=1.08-1.11). Here we used archived data, air mass trajectories and aerosol diameters combined with isotopic signatures to confirm this trend at a regional scale. Indeed, the main industrial signatures from lead smelting ( 206Pb/ 207Pb=1.133±0.001) and steel metallurgy ( 206Pb/ 207Pb=1.196±0.015) in northwestern France appear more radiogenic than that of leaded gasoline. The shift in isotopic compositions also conform with the systematic change in the mean size (diameter) of aerosols at Wimereux, which ranged from 0.30 to 0.61 μm in 1982-1984 and from 0.70 to 0.89 μm in 1994.

  14. High-resolution satellite-gauge merged precipitation climatologies of the Tropical Andes

    NASA Astrophysics Data System (ADS)

    Manz, Bastian; Buytaert, Wouter; Zulkafli, Zed; Lavado, Waldo; Willems, Bram; Robles, Luis Alberto; Rodríguez-Sánchez, Juan-Pablo

    2016-02-01

    Satellite precipitation products are becoming increasingly useful to complement rain gauge networks in regions where these are too sparse to capture spatial precipitation patterns, such as in the Tropical Andes. The Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (TPR) was active for 17 years (1998-2014) and has generated one of the longest single-sensor, high-resolution, and high-accuracy rainfall records. In this study, high-resolution (5 km) gridded mean monthly climatological precipitation is derived from the raw orbital TPR data (TRMM 2A25) and merged with 723 rain gauges using multiple satellite-gauge (S-G) merging approaches. The resulting precipitation products are evaluated by cross validation and catchment water balances (runoff ratios) for 50 catchments across the Tropical Andes. Results show that the TPR captures major synoptic and seasonal precipitation patterns and also accurately defines orographic gradients but underestimates absolute monthly rainfall rates. The S-G merged products presented in this study constitute an improved source of climatological rainfall data, outperforming the gridded TPR product as well as a rain gauge-only product based on ordinary Kriging. Among the S-G merging methods, performance of inverse distance interpolation of satellite-gauge residuals was similar to that of geostatistical methods, which were more sensitive to gauge network density. High uncertainty and low performance of the merged precipitation products predominantly affected regions with low and intermittent precipitation regimes (e.g., Peruvian Pacific coast) and is likely linked to the low TPR sampling frequency. All S-G merged products presented in this study are available in the public domain.

  15. Calcite Twin Analysis in the Central Andes of Northern Argentina and Southern Bolivia

    NASA Astrophysics Data System (ADS)

    Hardesty, E.; Hindle, D.

    2005-12-01

    The use of calcite twinning to infer compression directions and strain axes patterns has been applied widely in both fold and thrust belts, and continental interiors. Calcite twinning is noted to be one of the most precise methods for determining the internal strain of deformed rocks. Until now, such data from the deformed plate boundary of the Central Andes were lacking. This study has examined twinning orientations along the deformed Andean foreland (southern Bolivia and northern Argentina) from -25 to -20 latitude. In the Central Andes, we find an abundance of calcite twins in intervals of the Cretaceous age Yacorite limestone. Twin samples were collected, measured for orientation and type (I and II can be best used for strain analysis), and processed using the Groshong method, to give resultant strain tensors. The orientations of the twin short axes trend mostly NE-SW, which is close to the plate convergence direction. However, in a limited number of samples from the north, adjacent to the southern culmination of the active Subandean fold thrust belt, they trend NW-SE. This difference may be related to the more active, or more recent, shortening of the southern portion of the Eastern Cordillera, south of the culmination of the Subandean belt. This implies that twin short axes vary consistently with respect to geographic location and local tectonic regime. NW-SE trends in the northern region match well with fault kinematic studies in rocks pre-dating the San Juan del Oro unconformity (9-10 Ma). NE-SW trends in the south could correspond to much younger (~1-3 Ma) fault kinematic trends. In the Eastern Cordillera, where there is present day tectonic activity, the plunges of the twin short axes are found to be almost horizontal. This suggests that the twins were formed after folding occurred.

  16. Duck plague in free-flying waterfowl observed during the Lake Andes epizootic

    USGS Publications Warehouse

    Proctor, S.J.; Pearson, G.L.; Leibovitz, L.

    1975-01-01

    The first major epizootic of duck plague in free-flying waterfowl occurred at Lake Andes, South Dakota, in January and February, 1973. Duck plague was diagnosed in black ducks, mallards, pintail-mallard hybrids, redheads, common mergansers, common golden eyes, canvasbacks, American widgeon, wood ducks, and Canada geese, indicating the general susceptibility of ducks to duck plague. Clinical signs observed in mallards were droopiness, polydipsia, lethargy, reduced wariness, weakness, reluctance to fly, swimming in circles, bloody diarrhea, bloody fluid draining from the nares and bill, and terminal convulsions.Because the mallard was the most numerous and heavily infected species during the Lake Andes epizootic, gross and microscopic lesions of the gastrointestinal tract, liver, spleen, thymus, bursa of Fabricius, heart, lung, bone marrow, pancreas, and ovaries were described. Lesions of the esophagus and cloaca were in the stratified submucosal glands. In the small and large intestine, lesions were located in lymphocytic aggregates, lamina propria, and crypt epithelium. Hemorrhages and necrosis of hepatocytes and bile duct epithelium were noted in the liver. Diffuse necrosis of lymphocytic and reticuloendothelial tissue were evident in the spleen, bursa of Fabricius, and thymus. Hemorrhages in other tissues such as the lung and heart were often associated with lymphoid nodules, while those in organs such as the pancreas were associated with acinar necrosis. Intranuclear inclusion bodies were seen in stratified squamous epithelium of the esophagus and cloaca, crypt epithelium of the intestine, hepatocytes, bile duct epithelium, cells of Hassel's corpuscles, splenic periarteriolar reticular cells, and epithelial cells in the bursa of Fabricius.

  17. Exploring pain in the Andes--learning from the Quichua (Inca) people experience.

    PubMed

    Incayawar, Mario; Saucier, Jean-François

    2015-05-01

    There is a mounting recognition that culture profoundly shapes human pain experience. The 28 million indigenous people of the Andes in South America, mainly the Quichua (Inca) people, share a distinctive culture. However, little is known about their pain experience and suffering. The aim of the present study was to explore how Quichua adults perceive, describe, and cope with the pain. An exploratory qualitative/descriptive study was conducted with a convenience sample of 40 Quichua adults, including 15 women and 25 men, in the Northern Highlands of Ecuador. Data were collected through structured interviews of approximately 3 h, using a Quichua questionnaire called "The Nature of Pain" [Nanay Jahua Tapuicuna]. The interviews covered the notions of causation of pain, vulnerability to pain, responses to pain, aggravating factors, frequent locations of pain, types of pain, duration, characteristics of pain, control of pain, pathways to care, and preventive measures of pain. Basic descriptive analyses were performed. The Quichuas' pain experience is complex and their strategies to cope with it are sophisticated. According to the Quichuas, emotions, life events, co-morbid conditions, and spirits, among others factors play an important role in the origin, diagnosis, and treatment of pain. They strongly embrace biomedicine and physicians as well as Quichua traditional medicine and traditional healers. Family members and neighbors are also valuable sources of health care and pain control. The pathway to pain care that the Quichua people prefer is inclusive and pluralistic. The knowledge of the Quichua ethnographic "emic" details of their belief system and coping strategies to control pain are clinically useful not only for the health professional working in the Andes, some Quichua cultural characteristics related to pain could be useful to the culturally competent health practitioner who is making efforts to provide high-quality medical care in rural and multicultural

  18. Vitamin D Status among Older Adults Residing in the Littoral and Andes Mountains in Ecuador

    PubMed Central

    Orces, Carlos H.

    2015-01-01

    Objectives. To estimate the prevalence of 25-hydroxyvitamin D (25(OH)D) deficiency and its determinants among older adults in Ecuador. Methods. 25(OH)D deficiency and insufficiency prevalence rates were examined among participants in the National Survey of Health, Wellbeing, and Aging. Logistic regression models were used to evaluate demographic characteristics associated with 25(OH)D deficiency. Results. Of 2,374 participants with a mean age of 71.0 (8.3) years, 25(OH)D insufficiency and deficiency were present in 67.8% (95% CI, 65.3–70.2) and 21.6% (95% CI, 19.5–23.7) of older adults in Ecuador, respectively. Women (OR, 3.19; 95% CI, 3.15–3.22), self-reported race as Indigenous (OR, 2.75; 95% CI, 2.70–2.80), and residents in rural (OR, 4.49; 95% CI, 4.40–4.58) and urban (OR, 2.74; 95% CI, 2.69–2.80) areas of the Andes Mountains region were variables significantly associated with 25(OH)D deficiency among older adults. Conclusions. Despite abundant sunlight throughout the year in Ecuador, 25(OH)D deficiency was significantly prevalent among older women, Indigenous subjects, and subjects residing in the Andes Mountains region of the country. The present findings may assist public health authorities to implement policies of vitamin D supplementation among older adults at risk for this condition. PMID:26301259

  19. Inter-twined Hydrometeorology and Hydrogeomorphology in the Central Andes - Implications for Geomorphological Hazards

    NASA Astrophysics Data System (ADS)

    Deitz, R.; Barros, A. P.; Erlingis, J.

    2011-12-01

    The focus of this study includes the Central Andes Mountains between 11-15S and 70-75W, with heights ranging from about 230 m to 5700 meters. On March 4, 2010 an overnight storm caused over 200 landslides within one small river valley alone. The geologically young region is abundant with streams ranging from first to seventh order, as well as steep slopes, deep gorges, and broad valleys. Stream orders vary from 1-7 and watersheds of stream order 4 or higher were analyzed in detail. This resulted in the delineation of 112 watersheds ranging in area from roughly 360 km2 to 90,000 km2. Morphometric analysis, including Order and Hypsometry, were conducted for these basins. Results show that Horton's ratios are lower in the Central Andes compared to previous studies, and this is especially true for area ratios. A joint analysis of the hypsometric curve and distribution of stream orders with elevation shows that sharp breaks in the hypsometric curve are associated with specific stream orders and their distributions in the landscape. We hypothesize that these breaks are associated with extreme orographic precipitation events such as that which caused the March 2010 landslides. Subsequently, 10 years of TRMM precipitation features over the region were analyzed and mapped to investigate the co-organization of the drainage network and orographic precipitation patterns for the monsoon and dry seasons separately. The results will be discussed in the context of Montgomery al. (2001, Geology) and Giovannetone and Barros (2009, Journal of Hydrometeorology).

  20. Proliferation of Hydroelectric Dams in the Andean Amazon and Implications for Andes-Amazon Connectivity

    PubMed Central

    Finer, Matt; Jenkins, Clinton N.

    2012-01-01

    Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics. PMID:22529979

  1. Drivers of atmospheric methane uptake by montane forest soils in the southern Peruvian Andes

    NASA Astrophysics Data System (ADS)

    Jones, Sam P.; Diem, Torsten; Huaraca Quispe, Lidia P.; Cahuana, Adan J.; Reay, Dave S.; Meir, Patrick; Arn Teh, Yit

    2016-07-01

    The soils of tropical montane forests can act as sources or sinks of atmospheric methane (CH4). Understanding this activity is important in regional atmospheric CH4 budgets given that these ecosystems account for substantial portions of the landscape in mountainous areas like the Andes. We investigated the drivers of net CH4 fluxes from premontane, lower and upper montane forests, experiencing a seasonal climate, in south-eastern Peru. Between February 2011 and June 2013, these soils all functioned as net sinks for atmospheric CH4. Mean (standard error) net CH4 fluxes for the dry and wet season were -1.6 (0.1) and -1.1 (0.1) mg CH4-C m-2 d-1 in the upper montane forest, -1.1 (0.1) and -1.0 (0.1) mg CH4-C m-2 d-1 in the lower montane forest, and -0.2 (0.1) and -0.1 (0.1) mg CH4-C m-2 d-1 in the premontane forest. Seasonality in CH4 exchange varied among forest types with increased dry season CH4 uptake only apparent in the upper montane forest. Variation across these forests was best explained by available nitrate and water-filled pore space indicating that nitrate inhibition of oxidation or diffusional constraints imposed by changes in water-filled pore space on methanotrophic communities may represent important controls on soil-atmosphere CH4 exchange. Net CH4 flux was inversely related to elevation; a pattern that differs to that observed in Ecuador, the only other extant study site of soil-atmosphere CH4 exchange in the tropical Andes. This may result from differences in rainfall patterns between the regions, suggesting that attention should be paid to the role of rainfall and soil moisture dynamics in modulating CH4 uptake by the organic-rich soils typical of high-elevation tropical forests.

  2. Subduction and collision processes in the Central Andes constrained by converted seismic phases.

    PubMed

    Yuan, X; Sobolev, S V; Kind, R; Oncken, O; Bock, G; Asch, G; Schurr, B; Graeber, F; Rudloff, A; Hanka, W; Wylegalla, K; Tibi, R; Haberland, C; Rietbrock, A; Giese, P; Wigger, P; Röwer, P; Zandt, G; Beck, S; Wallace, T; Pardo, M; Comte, D

    The Central Andes are the Earth's highest mountain belt formed by ocean-continent collision. Most of this uplift is thought to have occurred in the past 20 Myr, owing mainly to thickening of the continental crust, dominated by tectonic shortening. Here we use P-to-S (compressional-to-shear) converted teleseismic waves observed on several temporary networks in the Central Andes to image the deep structure associated with these tectonic processes. We find that the Moho (the Mohorovicić discontinuity--generally thought to separate crust from mantle) ranges from a depth of 75 km under the Altiplano plateau to 50 km beneath the 4-km-high Puna plateau. This relatively thin crust below such a high-elevation region indicates that thinning of the lithospheric mantle may have contributed to the uplift of the Puna plateau. We have also imaged the subducted crust of the Nazca oceanic plate down to 120 km depth, where it becomes invisible to converted teleseismic waves, probably owing to completion of the gabbro-eclogite transformation; this is direct evidence for the presence of kinetically delayed metamorphic reactions in subducting plates. Most of the intermediate-depth seismicity in the subducting plate stops at 120 km depth as well, suggesting a relation with this transformation. We see an intracrustal low-velocity zone, 10-20 km thick, below the entire Altiplano and Puna plateaux, which we interpret as a zone of continuing metamorphism and partial melting that decouples upper-crustal imbrication from lower-crustal thickening.

  3. Eccentricity-driven fluvial fill terrace formation in the southern-central Andes, NW Argentina

    NASA Astrophysics Data System (ADS)

    Tofelde, Stefanie; Savi, Sara; Wickert, Andrew D.; Wittmann, Hella; Alonso, Ricardo; Strecker, Manfred R.; Schildgen, Taylor F.

    2016-04-01

    Across the world, fill-terrace formation in glaciated catchments has been linked to variable sediment production and river discharge over glacial-interglacial cycles. Little is known, however, how variability in global climate may have affected rainfall patterns and associated surface-processes on multi-millennial timescales in regions far from major glaciers and ice sheets, and how those changes might be reflected in the landscape. Here, we investigate the timing of fluvial fill terrace planation and abandonment in the Quebrada del Toro, an intermontane basin located in the Eastern Cordillera of the southern-central Andes of NW Argentina. Fluvial fills in the valley reach more than 150 m above the current river level. Sculpted into the fills, we observe at least 5 terrace levels with pronounced differences in their extent and preservation. We sampled four TCN (in situ 10Be) depth profiles to date the abandonment of the most extensive terrace surfaces in locations, where subsequent overprint by erosion and deposition was not pronounced. We interpret unexpectedly low 10Be concentrations at shallow depths and surface samples to be related to aeolian input, causing surface inflation. Correcting the depth profiles for inflation results in a reduction of the terrace surface ages by up to 70 ka. The inflation-corrected ages fall within the late Pleistocene (~140 - 370 ka) and suggest a potential link to orbital eccentricity (~100 ka) cycles. The studied fills in the Toro Basin document successive episodes of incision, punctuated by periods of lateral planation and possible partial re-filling. We propose climate cycles as a potentially-dominant factor in forming these terraces. To our knowledge, none of the previously studied fluvial terraces in the Andes date back more than 2 glacial cycles, thus making the Quebrada del Toro an important archive of paleoenvironmental conditions over longer timescales.

  4. Variation in freshwater fish assemblages along a regional elevation gradient in the northern Andes, Colombia

    PubMed Central

    Carvajal-Quintero, Juan D; Escobar, Federico; Alvarado, Fredy; Villa-Navarro, Francisco A; Jaramillo-Villa, Úrsula; Maldonado-Ocampo, Javier A

    2015-01-01

    Studies on elevation diversity gradients have covered a large number of taxa and regions throughout the world; however, studies of freshwater fish are scarce and restricted to examining their changes along a specific gradient. These studies have reported a monotonic decrease in species richness with increasing elevation, but ignore the high taxonomic differentiation of each headwater assemblage that may generate high β-diversity among them. Here, we analyzed how fish assemblages vary with elevation among regional elevation bands, and how these changes are related to four environmental clines and to changes in the distribution, habitat use, and the morphology of fish species. Using a standardized field sampling technique, we assessed three different diversity and two structural assemblage measures across six regional elevation bands located in the northern Andes (Colombia). Each species was assigned to a functional group based on its body shape, habitat use, morphological, and/or behavioral adaptations. Additionally, at each sampling site, we measured four environmental variables. Our analyses showed: (1) After a monotonic decrease in species richness, we detected an increase in richness in the upper part of the gradient; (2) diversity patterns vary depending on the diversity measure used; (3) diversity patterns can be attributed to changes in species distribution and in the richness and proportions of functional groups along the regional elevation gradient; and (4) diversity patterns and changes in functional groups are highly correlated with variations in environmental variables, which also vary with elevation. These results suggest a novel pattern of variation in species richness with elevation: Species richness increases at the headwaters of the northern Andes owing to the cumulative number of endemic species there. This highlights the need for large-scale studies and has important implications for the aquatic conservation of the region. PMID:26257874

  5. Synchronous fire activity in the tropical high Andes: an indication of regional climate forcing.

    PubMed

    Román-Cuesta, R M; Carmona-Moreno, C; Lizcano, G; New, M; Silman, M; Knoke, T; Malhi, Y; Oliveras, I; Asbjornsen, H; Vuille, M

    2014-06-01

    Global climate models suggest enhanced warming of the tropical mid and upper troposphere, with larger temperature rise rates at higher elevations. Changes in fire activity are amongst the most significant ecological consequences of rising temperatures and changing hydrological properties in mountainous ecosystems, and there is a global evidence of increased fire activity with elevation. Whilst fire research has become popular in the tropical lowlands, much less is known of the tropical high Andean region (>2000 masl, from Colombia to Bolivia). This study examines fire trends in the high Andes for three ecosystems, the Puna, the Paramo and the Yungas, for the period 1982-2006. We pose three questions: (i) is there an increased fire response with elevation? (ii) does the El Niño- Southern Oscillation control fire activity in this region? (iii) are the observed fire trends human driven (e.g., human practices and their effects on fuel build-up) or climate driven? We did not find evidence of increased fire activity with elevation but, instead, a quasicyclic and synchronous fire response in Ecuador, Peru and Bolivia, suggesting the influence of high-frequency climate forcing on fire responses on a subcontinental scale, in the high Andes. ENSO variability did not show a significant relation to fire activity for these three countries, partly because ENSO variability did not significantly relate to precipitation extremes, although it strongly did to temperature extremes. Whilst ENSO did not individually lead the observed regional fire trends, our results suggest a climate influence on fire activity, mainly through a sawtooth pattern of precipitation (increased rainfall before fire-peak seasons (t-1) followed by drought spells and unusual low temperatures (t0), which is particularly common where fire is carried by low fuel loads (e.g., grasslands and fine fuel). This climatic sawtooth appeared as the main driver of fire trends, above local human influences and fuel build

  6. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    PubMed

    Finer, Matt; Jenkins, Clinton N

    2012-01-01

    Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  7. Progenitor–derivative speciation in Pozoa (Apiaceae, Azorelloideae) of the southern Andes

    PubMed Central

    López, Patricio; Tremetsberger, Karin; Kohl, Gudrun; Stuessy, Tod

    2012-01-01

    Background and Aims Studies examining patterns and processes of speciation in South America are fewer than in North America and Europe. One of the least well documented processes has been progenitor–derivative speciation. A particularly instructive example occurs in the southern Andes in the genus Pozoa (Apiaceae, Azorelloideae), which consists of only two diploid outcrossing species, the widespread P. coriacea and the geographically and ecologically restricted P. volcanica. This paper tests the hypothesis that the latter species originated from the former through local geographical and ecological isolation by progenitor–derivative speciation. Methods DNA sequences were analysed from Pozoa and the related South American genera Asteriscium, Eremocharis and Gymnophyton from non-coding regions of the plastid genome, ndhF-rpl32 and rpl32-trnL, plus incorporation of previously reported rpl16 intron and trnD-trnT intergenic spacer sequences. Amplified fragment length polymorphism (AFLP) data from 105 individuals in 21 populations throughout the entire range of distribution of the genus were used for estimation of genetic diversity, divergence and SplitsTree network analysis. Ecological factors, including habitat and associated species, were also examined. Key Results Pozoa coriacea is more similar genetically to the outgroup genera, Asteriscium and Eremocharis, than is P. volcanica. At the population level, only P. volcanica is monophyletic, whereas P. coriacea is paraphyletic. Analyses of genetic differentiation among populations and genetic divergence and diversity of the species show highest values in P. coriacea and clear reductions in P. volcanica. Pozoa coriacea occurs in several types of high elevation habitats, whereas P. volcanica is found only in newly formed open volcanic ash zones. Conclusions All facts support that Pozoa represents a good example of progenitor–derivative speciation in the Andes of southern South America. PMID:22112441

  8. TCF7L2 rs7903146 polymorphism is associated with gastric cancer: A case-control study in the Venezuelan population

    PubMed Central

    Torres, Keila; Labrador, Luis; Valderrama, Elvis; Chiurillo, Miguel Angel

    2016-01-01

    AIM: To explore the association between TCF7L2 rs12255372 and rs7903146 single nucleotide polymorphisms (SNPs) and gastric cancer risk in Venezuelan patients. METHODS: We performed a case-control study including 122 paraffin-embedded archived intestinal-type gastric cancer samples and 129 biopsies obtained by superior endoscopy from chronic gastritis patients. Gastric cancer samples were classified according the degree of carcinoma differentiation. Genomic DNA was extracted from tissues, and the two SNPs of TCF7L2 gene (rs12255372 and rs7903146) were genotyped by polymerase chain reaction-restriction fragment length polymorphism reactions. Multiple regression analysis with adjustments for age and gender were performed and best-fitting models of inheritance were determined. Statistic powers were post-hoc calculated. RESULTS: After adjusting for age and sex the TCF7L2 rs7903146 TT genotype was associated with gastric cancer risk under the recessive genetic model (OR = 3.11, 95%CI: 1.22-7.92, P = 0.017). We further investigated the distribution of rs12255372 and rs7903146 genotypes according gastric cancer stratified by degree of differentiation, and we observed that carriers of rs7903146 T allele (CT + TT vs CC) had a significantly increased risk of moderate/well differentiated gastric cancer (dominant model, OR = 2.55, 95%CI: 1.35-4.80, P = 0.004), whereas the rs7903146 TT genotype was associated with poorly differentiated gastric cancer in the recessive model (OR = 3.65, 95%CI: 1.25-10.62, P = 0.018). We did not find association between rs12255372 SNP and the susceptibility of developing gastric cancer. CONCLUSION: TCF7L2 rs7903146 polymorphism is associated with gastric cancer risk in the Venezuelan population, and could be related to determine the degree of differentiation of tumor cells. PMID:27605886

  9. On the Nature of Severe Orographic Thunderstorms near the Andes in Subtropical South America

    NASA Astrophysics Data System (ADS)

    Rasmussen, Kristen Lani Emi

    Identifying common features and differences between the mechanisms producing extreme convection near major mountain ranges of the world is an essential step toward a general understanding of orographic precipitation on a global scale. The overarching objective of this dissertation is to understand and examine orographic convective processes in general, while specifically focusing on systems in the lee of the Andes Mountains. Diagnosing the key ingredients necessary for generating high impact weather near extreme topography is crucial to our understanding of orographic precipitating systems. An investigation of the most intense storms in 11 years of TRMM Precipitation Radar (PR) data has shown a tendency for squall lines to initiate and develop east of the Andes with a mesoscale organization similar to storms in the U.S. Great Plains (Rasmussen and Houze 2011). In subtropical South America, however, the topographical influence on the convective initiation and maintenance of the mesoscale convective systems (MCSs) is unique. The Andes and other mountainous terrain of Argentina focus deep convective initiation in the foothills of western Argentina (Romatschke and Houze 2010; Rasmussen and Houze 2011). Subsequent to initiation, the convection often evolves into propagating MCSs similar to those seen over the U.S. Great Plains sometimes producing damaging tornadoes, hail and floods across a wide agricultural region (Rasmussen and Houze 2011; Rasmussen et al. 2014b). The TRMM satellite was designed to determine the spatial and temporal variation of tropical and subtropical rainfall amounts and storm structures around the globe with the goal of understanding the factors controlling the precipitation. However, the TRMM PR algorithm significantly underestimates surface rainfall in deep convection over land (Nesbitt et al. 2004; Iguchi et al. 2009; Kozu et al. 2009). When the algorithm rates are compared to a range of conventional Z-R relations, the rain bias tends to be

  10. Isotopic characterization of mountain precipitation along the eastern flank of the Andes between 32.5 - 35°S

    NASA Astrophysics Data System (ADS)

    Hoke, G. D.; Aranibar, J. N.; Viale, M.; Araneo, D. C.; LLano, C. L.

    2011-12-01

    Data describing the isotopic composition of precipitation in the Andes are sparse: on the South American continent one IAEA Global Network of Isotopes in Precipitation (GNIP) station above 1500 m elevation exists south of La Paz. Better spatial density is necessary to improve our understanding of isotopes in mountain precipitation, which has implications for how to interpret isotopic information from the geologic record and the validation of isotope tracking modules in climate models. We present finding from two-years of quasi-monthly precipitation collection on the eastern flank of the Andes between 32.5 and 35°S latitude. A total of 123 samples were collected from 10 stations from Setember 2008 until September 2010. North of 33°S, the 2500 m average elevation Precordillera forms a steep front orographic barrier and the 2000 m elevation Uspallata Valley separates the Precordillera from the high Andes to the East. South of 33°S the Precordillera ends and the Andes return to a simple linear morphology. The low-leeward (eastern) side of the Andes receives predominately summer precipitation from convective storms, usually triggered by daytime upslope flow or synoptic-scale easterly flow over the Precordillera. Moving westward from the low-leeward side to the range crest, the influence of the easterly summer precipitation wanes and winter spillover precipitation from mid-latitude westerly storms beings to dominate. Our results show the local meteoric water line is slightly steeper (~0.5) than the global meteoric water line and a y-intercept of 14. The most negative δ18O values vary as much as 15 per mil seasonally, while averages weighted by precipitation amount show a strong cross-barrier (elevation) dependence. At these latitudes, the weighted average precipitation δ18O values show a significant deviation from river water near the range crest. The influence of the different moisture sources, from synoptic-scale easterly or westerly flow, is distinguished by

  11. Current state of glaciers in the tropical Andes: a multi-century perspective on glacier evolution and climate change

    NASA Astrophysics Data System (ADS)

    Rabatel, A.; Francou, B.; Soruco, A.; Gomez, J.; Cáceres, B.; Ceballos, J. L.; Basantes, R.; Vuille, M.; Sicart, J.-E.; Huggel, C.; Scheel, M.; Lejeune, Y.; Arnaud, Y.; Collet, M.; Condom, T.; Consoli, G.; Favier, V.; Jomelli, V.; Galarraga, R.; Ginot, P.; Maisincho, L.; Mendoza, J.; Ménégoz, M.; Ramirez, E.; Ribstein, P.; Suarez, W.; Villacis, M.; Wagnon, P.

    2013-01-01

    The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the Little Ice Age (LIA, mid-17th-early 18th century). In terms of changes in mass balance, although there have been some sporadic gains on several glaciers, we show that the trend has been quite negative over the past 50 yr, with a mean mass balance deficit for glaciers in the tropical Andes that is slightly more negative than the one computed on a global scale. A break point in the trend appeared in the late 1970s with mean annual mass balance per year decreasing from -0.2 m w.e. in the period 1964-1975 to -0.76 m w.e. in the period 1976-2010. In addition, even if glaciers are currently retreating everywhere in the tropical Andes, it should be noted that this is much more pronounced on small glaciers at low altitudes that do not have a permanent accumulation zone, and which could disappear in the coming years/decades. Monthly mass balance measurements performed in Bolivia, Ecuador and Colombia show that variability of the surface temperature of the Pacific Ocean is the main factor governing variability of the mass balance at the decadal timescale. Precipitation did not display a significant trend in the tropical Andes in the 20th century, and consequently cannot explain the glacier recession. On the other hand, temperature increased at a significant rate of 0.10 °C decade-1 in the last 70 yr. The higher frequency of El Niño events and changes in its spatial and temporal occurrence since the late 1970s together with a warming troposphere over the tropical Andes may thus explain much of the recent dramatic shrinkage of glaciers in this part of the world.

  12. 78 FR 53175 - The Northwestern Mutual Life Insurance Company, et al.;

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION The Northwestern Mutual Life Insurance Company, et al.; Notice of Application Agency: Securities and Exchange Commission (``SEC'' or ``Commission'') August 22, 2013. ACTION: Notice of application...

  13. [High energy physics research]: Annual performance report, December 1, 1991--November 30, 1992. [Northwestern Univ

    SciTech Connect

    Rosen, J; Block, M; Buchholz, D; Gobbi, B; Schellman, H; Buchholz, D; Rosen, J; Miller, D; Braaten, E; Chang, D; Oakes, R; Schellman, H

    1992-01-01

    The various segments of the Northwestern University high energy physics research program are reviewed. Work is centered around experimental studies done primarily at FNAL; associated theoretical efforts are included.

  14. 78 FR 9327 - Hawaii Crustacean Fisheries; 2013 Northwestern Hawaiian Islands Lobster Harvest Guideline

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 665 RIN 0648-XC453 Hawaii Crustacean Fisheries; 2013 Northwestern Hawaiian Islands Lobster Harvest Guideline AGENCY: National Marine Fisheries...

  15. 76 FR 77214 - Hawaii Crustacean Fisheries; 2012 Northwestern Hawaiian Islands Lobster Harvest Guideline

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XA838 Hawaii Crustacean Fisheries; 2012 Northwestern Hawaiian Islands Lobster Harvest Guideline AGENCY: National Marine Fisheries Service...

  16. 76 FR 4551 - Hawaii Crustacean Fisheries; 2011 Northwestern Hawaiian Islands Lobster