WorldWideScience

Sample records for northwestern south america

  1. The ribbon continent of northwestern South America

    Science.gov (United States)

    Altamira-Areyan, Armando

    The tectonic structure of the Plate Boundary Zone (PBZ) between the Caribbean Plate (CARIB) and the South American Plate (SOAM) is interpreted using models that require CARIB motion from the Pacific into the Atlantic. Those models can be subdivided into: (1) those in which the island arc rocks that are now in the CARIB-SOAM PBZ have collided with the northern South America margin, either obliquely or directly during the Cretaceous or during the Cenozoic, and (2) those in which the island arc rocks now in the CARIB-SOAM PBZ collided with the west coast of South America during the Cretaceous and were transferred to the northern margin by transform motion during the Cenozoic. Magnetic anomalies were first rotated in the Central and South Atlantic, holding Africa fixed to establish how much NOAM had converged on SOAM during the Cenozoic. WSW convergence was discovered to have been accommodated in the northern boundary of the CARIB. There is no evidence of convergence in the form of Cenozoic island arc igneous rocks on the north coast of South America. Those results are consistent only with models of Class (2) that call for transform movement of material that had collided with the west coast of South America along the CARIB-SOAM PBZ on the northern margin of South America. 40Ar/39Ar ages of island arc rocks from northern Venezuela were found to be older than ca 70 Ma, which is consistent with a requirement of models of Class (2) that those rocks are from an island arc which collided with the west coast of South America during Cretaceous times. Testing that conclusion using data from Ecuador, Colombia, Venezuela, the Netherlands Antilles, Trinidad and Tobago has led to the construction of a new ribbon continent model of the northwestern Cordillera of South America. Because the part of the ribbon continent on the north coast of South America has been experiencing substantial deformation in the Maracaibo block during the past 10 m.y., structures in that body have had to be

  2. Palm harvest impacts in north-western South America

    DEFF Research Database (Denmark)

    Balslev, Henrik

    2011-01-01

    Tropical forests harbor thousands of useful plants that are harvested and used in subsistence economies or traded in local, regional or international markets. The effect on the ecosystem is little known, and the forests resilience is badly understood. Palms are the most useful group of plants...... in tropical American forests. This paper introduces a cross-disciplinary study of the effects of harvesting palm products from the tropical forests in north-western South America. The size of the resource is estimated through palm community studies in the different forest formations that determines the number...... for subsistence purposes Quantitative ethno-botanical research in different forest types have identified thousands of different ways of using palms for food, construction, tool-making, etc. Although most palms are used by the person harvesting them, many are sold on local markets as fruits, fiber, tools...

  3. Deformation of Northwestern South America from GPS Geodesy

    Science.gov (United States)

    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

  4. Tectonic implications of tomographic images of subducted lithosphere beneath northwestern South America

    NARCIS (Netherlands)

    Hilst, R.D. van der; Mann, P.

    1994-01-01

    We used seismic tomography to investigate the complex structure of the upper mantle below northwestern South America. Images of slab structure not delineated by previous seismicity studies help us to refine existing tectonic models of subducted Caribbean-Pacific lithosphere beneath the study area. B

  5. The Cocos Ridge drives collision of Panama with northwestern South America

    Science.gov (United States)

    LaFemina, Peter; Govers, Rob; Mora-Paez, Hector; Geirsson, Halldor; Cmacho, Eduardo

    2015-04-01

    The collision of the Panamanian isthmus with northwestern South America is thought to have initiated as early as Oligocene - Miocene time (23-25 Ma) based on geologic and geophysical data and paleogeographic reconstructions. This collision was driven by eastward-directed subduction beneath northwestern South America. Cocos - Caribbean convergence along the Middle America Trench, and Nazca - Caribbean oblique convergence along the South Panama Deformed Belt have resulted in complex deformation of the southwestern Caribbean since Miocene - Pliocene time. Subduction and collision of the aseismic Cocos Ridge is thought to have initiated volcanism and uplift of the Cordillera de Talamanca; 2) Quaternary migration of the volcanic arc toward the back-arc; 3) Quaternary to present deformation within the Central Costa Rica Deformed Belt; 4) Quaternary to present shortening across the fore-arc Fila Costeña fold and thrust belt and back-arc North Panama Deformed Belt (NPDB); 5) Quaternary to present outer fore-arc uplift of Nicoya Peninsula above the seamount domain, and the Osa and Burica peninsulas above the ridge; and 6) Pleistocene to present northwestward motion of the Central American Fore Arc (CAFA) and northeastward motion of the Panama Region. We investigate the geodynamic effects of Cocos Ridge collision on motion of the Panama Region with a new geodynamic model. The model is compared to a new 1993-2015 GPS-derived three-dimensional velocity field for the western Caribbean and northwestern South America. Specifically, we test the hypotheses that the Cocos Ridge is the main driver for upper plate deformation in the western Caribbean. Our models indicate that Cocos Ridge collision drives northwest-directed motion of the CAFA and the northeast-directed motion of the Panama Region. The Panama Region is driven into the Caribbean across the NPDB and into northwestern South America, which is also converging with the Panama Region, pushing it toward the west

  6. CRUSTAL THICKNESS VARIATIONS AND SEISMICITY OF NORTHWESTERN SOUTH AMERICA

    Directory of Open Access Journals (Sweden)

    Woo Kim Jeong

    2007-06-01

    Full Text Available Any uncompensated mass of the northern Andes Mountains is presumably under pressure to adjust within the Earth to its ideal state of isostatic equilibrium. Isostasy is the ideal state that any
    uncompensated mass seeks to achieve in time. These pressures interact with the relative motions between adjacent plates that give rise to earthquakes along the plate boundaries. By combining the
    gravity MOHO estimates and crustal discontinuities with historical and instrumental seismological catalogs the correlation between isostatically disturbed terrains and seismicity has been established.
    The thinner and thicker crustal regions were mapped from the zero horizontal curvature of the crustal thickness estimates. These boundaries or edges of crustal thickness variations were compared to
    crustal discontinuities inferred from gravity and magnetic anomalies and the patterns of seismicity that have been catalogued for the last 363 years. The seismicity is very intense along the Nazca-North
    Andes, Caribbean-North American and North Andes-South American collision zones and associated with regional tectonic compressional stresses that have locally increased and/or diminished by
    compressional and tensional stress, respectively, due to crustal thickness variations. High seismicity is also associated with the Nazca-Cocos diverging plate boundary whereas low seismicity is associated with the Panama-Nazca Transform Fault and the South American Plate.

  7. The choco block in the northwestern corner of South America: Structural, tectonostratigraphic, and paleogeographic implications

    Science.gov (United States)

    Duque-Caro, H.

    The Choco Block, located in the northwestern corner of South America, comprises the isthmus of Panama east of the Canal Zone and northwestern Colombia, including the westernmost flanks of the Cordillera Occidental above latitude 4°N. Three major structural and lithogenetic elements compose this terrain: the Dabeiba and Baudo Arches, the Atrato-Chucunaque Basins, and the Istmina Deformed Zone. The Dabeiba and Baudo Arches outline the external boundaries of the Choco Block and display similar characteristics: (a) mostly positive gravity anomalies and association of igneous bodies of oceanic origin with sedimentary suites, and (b) occurence of Upper Cretaceous to Miocene pelagic and hemipelagic and terrigenous strata in blocks of different ages and environments associated with mafic igneous rocks. The Dabeiba Arch exhibits a melange fabric, particularly at its eastern margin, in which disrupted strata and inclusions of Upper Cretaceous-Paleocene, Eocene-Oligocene, and Miocene exotic blocks are dispersed in a sheared pelitic matrix of middle Miocene age. The Atrato-Chucunaque Basins contain sedimentary fill exceeding 10 km in thickness. Two distinctive stratigraphic sequences comprise: (1) an outcropping and apparently continuous Oligocene to middle Miocene sequence composed mostly of pelagic and hemipelagic strata, overlain by hemipelagic and terrigenous strata of latest Middle Miocene to Pliocene age, and (2) an underlying middle Miocene and older sequence, composed mostly of turbidities, which has been recognized only in subsurface sections. An evaluation and synthesis of the structural and lithogenetic information of the Choco Block indicate the following conclusions. The Choco Block is an exotic terrane with no lithogenetic affinity with South America, accreted onto the northwestern flanks of the Cordillera Occidental during the middle Miocene. The occurence of exotic upper Paleocene planktic foraminiferal assemblages in the Dabeiba Arch suggests an origin for

  8. Deformation of the Western Caribbean and Northwestern South America From GPS Geodesy

    Science.gov (United States)

    LaFemina, Peter; Mora-Paez, Hector; Kobayashi, Daisuke; Fernandes, Rui; Mothes, Patricia

    2014-05-01

    We investigate the current kinematics of the western Caribbean and northwestern South America, two regions that are affected by ongoing collision of aseismic ridges and the motion of forearc slivers. We investigate these regions using a new PS derived surface velocity field spanning from Guatemala to Ecuador. The new velocity field and published earthquake slip vectors are inverted to solve for the Euler vectors of forearc blocks and interseismic elastic strain accumulation on block bounding faults using a block modeling approach. Along the western Caribbean margin, it has been demonstrated that the Cocos Ridge collision drives the Central American forearc block to the northwest. GPS network expansion in Panama and Colombia allows us to investigate the effect of ridge collision on the Panama region. In northwestern South America, the North Andes block (NAB) is a hypothesized tectonic block that migrates 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 or by oblique convergence and high degrees of interplate coupling north of the ridge (i.e., strain partitioning). We test a suite of block models to investigate the tectonic nature of the Panama Region and North Andes block 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 earthquake and upper plate faults capable of M>6 earthquake.

  9. Integrated Provenance Studies in Northwestern South America, Linking Tectonic and Sedimentary Processes

    Science.gov (United States)

    Montes, C.; Cardona, A.; Ramirez, V. O.; Bayona, G.; Ayala, C.; Valencia, V.

    2009-12-01

    Post-collisional late Eocene to Oligocene extensional basins (Plato-San Jorge basin in Colombia) and syn-collisional basins to the east contain the record of drainages and source areas as a former passive margin obliquely collided with the Caribbean deformation front. A 2 to 8 km thick, shallowing-upward and almost entirely fine-grained, upper Eocene and younger sedimentary sequence contains the record of post-collisional paleogeography behind the advancing deformation front. Sedimentation in the syn-collisional margin is fragmentary along the northern margins of Colombia and Venezuela in the Guajira province. An integrated provenance approach is being undertaken with detrital zircon geochronology, whole rock geochemistry, heavy mineral analysis and tectonic modeling. Source areas contain distinctive assemblages that should be diagnostic and include cratonic contributions with Grenville and older provinces, Andean contributions with Mesozoic-age signatures and Caribbean contributions with latest Cretaceous and Paleogene contributions. The complex Paleogene tectonic interactions along the northwestern South American margin include the simultaneous opening of basins (Plato-San Jorge basin in Colombia), micro-block rotation (Santa Marta massif), shortening and mountain building (Perija range) and oblique accretionary wedges along the margin (Sinu-San Jacinto deformed belts). Rivers draining the interior of South America to the north would have been deflected by this Paleogene configuration, and local drainages would have similarly developed in response to changing depocenters. Distinctive signatures should have developed in the sedimentary sequence as the sources dynamically changed from cratonic (Grenville and older cratonic) to Andean (Mesozoic continental crust and reworked) to Caribbean (volcanic arcs and collision zones).

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

    Directory of Open Access Journals (Sweden)

    Rodrigo Cámara-Leret

    Full Text Available 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.

  11. Quantitative ethnobotany of palms in northwestern South America: a comparative analysis in Amazonia, Andes and Chocó

    DEFF Research Database (Denmark)

    Cámara-Leret, Rodrigo

    and socioeconomic factors of informants is presented in Chapter 2. In Chapter 3, the field data were used to compare and validate the quality and coverage of palm ethnobotanical information from a literature review of works published over the last 60 years in the same region. The results of this study show...... the highest contribution to the use value of forests. In Chapter 5 the geographical distribution of traditional knowledge is investigated using field data and bibliographic information about the medicinal uses of palms in northwestern South America. Comparisons are made across four countries, 52 Amerindian...

  12. Molecular phylogenetics of the white-lipped peccary (Tayassu pecari) did not confirm morphological subspecies in northwestern South America.

    Science.gov (United States)

    Ruiz-García, M; Pinedo-Castro, M; Luengas-Villamil, K; Vergara, C; Rodriguez, J A; Shostell, J M

    2015-05-22

    We sequenced the mitochondrial DNA (mtDNA) control region of 59 peccaries (44 white-lipped peccaries, Tayassu pecari, and 15 collared peccaries, Pecari tajacu). We also genotyped 3 DNA microsatellites from 78 white-lipped peccaries representing the 4 putative morphological subspecies (i.e., spiradens, aequatoris, pecari, and albirostris) present in northwestern South America (i.e., Colombia, Ecuador, Peru, and Bolivia). Our results showed: 1) the estimated diversity of the mtDNA control region in the T. pecari population was extremely high, whereas the average genetic diversity for the microsatellites was medium to high and similar to that observed in European pig breeds; 2) there was no significant genetic heterogeneity among the quoted putative morphological subspecies at the mitochondrial marker, but we did detect significant (although relatively small) genetic heterogeneity using microsatellites, indicating that T. pecari albirostris is a uniquely differentiated group; and 3) the phylogenetic mtDNA trees showed that haplotypes were intermixed independent of their "a priori" subspecies classification. In addition, the microsatellite assignation analyses yielded low percentages of well-classified individuals when the analysis considered the geographic morphology of the subspecies. Thus, the molecular results do not support the putative morphological subspecies of T. pecari in northwestern South America. Finally, our results did not detect clear historical demographic changes using the mtDNA control region sequences. These genetic results are discussed in the context of the ecological and social characteristics of T. pecari.

  13. The Vichada Impact Crater in Northwestern South America and its Potential for Economic Deposits

    Science.gov (United States)

    Hernandez, O.; von Frese, R. R.

    2008-05-01

    A prominent positive free-air gravity anomaly mapped over a roughly 50-km diameter basin is consistent with a mascon centered on (4o30`N, -69o15`W) in the Vichada Department, Colombia, South America. The inferred large impact crater is nearly one third the size of the Chicxulub crater. It must have formed recently, in the last 30 m.a. because it controls the partially eroded and jungle-covered path of the Vichada River. No antipodal relationship has been detected. Thick sedimentary cover, erosional processes and dense vegetation greatly limit direct geological testing of the inferred impact basin. However, EGM-96 gravity data together with ground gravity and magnetic profiles support the interpretation of the impact crater structure. The impact extensively thinned and disrupted the Precambrian cratonic crust and may be associated with mineral and hydrocarbon deposits. A combined EM and magnetic airborne program is being developed to resolve additional crustal properties of the inferred Vichada impact basin Keywords: Impact crater, economic deposits, free-air gravity anomalies

  14. GEOPHYSICAL EVIDENCE FOR AN IMPACT CRATER IN VICHADA, NORTHWESTERN SOUTH AMERICA AND ITS ECONOMIC POTENTIAL

    Directory of Open Access Journals (Sweden)

    Hernández Orlando

    2009-12-01

    Full Text Available A prominent positive free-air gravity anomaly mapped over a roughly 50-km diameter basin is consistent with a mascon centered on (4°30'N, -69°15'W in the Vichada Department, Colombia, South America. The inferred impact crater is nearly one third the size of the Chicxulub Crater. It must have formed recently, in the last 30 m.a because it controls the path of the Vichada River. The impact crater structure has been partially eroded and is almost completely covered by vegetation. No antipodal relationship has been established. The proposed impact appears to have contributed to the development of mineral deposits of economic interest. The impact shock waves extensively thinned and disrupted the Precambrian cratonic crust. Athick sedimentary cover, dense vegetation and erosional processes greatly limits direct geological testing of the inferred impact basin. Ground follow up gravity and magnetic surveys are recommended for confirming the regional free air gravity anomalies.

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

    Science.gov (United States)

    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.

  16. The influence of socioeconomic factors on the conservation of traditional knowledge: a cross scale comparison of palm use in Northwestern South America

    DEFF Research Database (Denmark)

    Paniagua-Zambrana, Narel; Cámara-Leret, Rodrigo; Bussmann, Rainer W.

    2014-01-01

    knowledge or on individual use categories. At the general palm knowledge level, gender was the only factor that had a significant association in all five subregions, and showed that men had more knowledge than women, and age had a positive significant association only in the lowlands. Most of the analyzed......We explored the power of 14 socioeconomic factors for predicting differences in traditional knowledge about palms (Arecaceae) at the personal, household, and regional levels in 25 locations in the Amazon, Andes, and Chocó of northwestern South America. Using semistructured interviews, we gathered...... data on palm uses from 2050 informants in 53 communities and four countries (Colombia, Ecuador, Peru, and Bolivia ). We performed multilevel statistical analyses, which showed that the influence of each socioeconomic factor differed depending on whether the analysis was performed on the overall palm...

  17. Crustal density structure in northwestern South America derived from analysis and 3-D modeling of gravity and seismicity data

    Science.gov (United States)

    Sanchez-Rojas, J.; Palma, M.

    2014-11-01

    This paper presents a three-dimensional (3-D) interpretation of new gravity and seismicity datasets for northern South America. A 3-D forward density model was constructed on the basis of deep wide-angle seismic refraction sections, Moho depth from receiver functions, and surface geology. Density values were estimated from published borehole data for sediments by using empirical velocity-density functions and considering mineralogical-chemical composition variations under typical pressure-temperature conditions for upper and lower crustal rocks. The modeled 3-D density structure was kept as simple as possible. The continental and oceanic plates were formed by two sedimentary bodies, one crustal body, and one mantle lithosphere body overlying a sub-lithospheric mantle. The Caribbean plate was modeled with an atypical crustal thickness of ~ 18 km (including sediments). The geometry of the Caribbean plate was modeled using a combination of gravity modeling and analyses of the seismicity and focal-mechanism solutions. Intermediate seismicity and the orientation of the T-axes appeared aligned along the predicted position of the slab. As a result, the estimated slab dip angle under Maracaibo and the Mérida Andes was ~ 15° and increases up to ~ 20° after 100 km depth. The model shows two orientations in the slab strike: ~ N150°E ± 5 in western Colombia and southward underneath the Maracaibo block. The modeling results suggest that the northern South American upper and lower crusts are relatively light and the density of the Caribbean crust is typical for an oceanic crust.

  18. Anaglyph, South America

    Science.gov (United States)

    2003-01-01

    This anaglyph (stereoscopic view) of South America was generated with data from the Shuttle Radar Topography Mission (SRTM). It is best viewed at or near full resolution with anaglyph glasses. For this broad view the resolution of the data was first reduced to 30 arcseconds (about 928 meters north-south but variable east-west), matching the best previously existing global digital topographic data set called GTOPO30. The data were then resampled to a Mercator projection with approximately square pixels (about one kilometer, or 0.6 miles, on each side). Even at this decreased resolution the variety of landforms comprising the South American continent is readily apparent.Topographic relief in South America is dominated by the Andes Mountains, which extend all along the Pacific Coast. These mountains are created primarily by the convergence of the Nazca and South American tectonic plates. The Nazca Plate, which underlies the eastern Pacific Ocean, slides under western South America resulting in crustal thickening, uplift, and volcanism. Another zone of plate convergence occurs along the northwestern coast of South America where the Caribbean Plate also slides under the South American Plate and forms the northeastern extension of the Andes Mountains.East of the Andes, much of northern South America drains into the Amazon River, the world's largest river in terms of both watershed area and flow volume. Topographic relief is very low in much of the Amazon Basin but SRTM data provide an excellent detailed look at the basin's three-dimensional drainage pattern, including the geologic structural trough (syncline) that hosts the eastern river channel.North of the Amazon, the Guiana Highlands commonly stand in sharp contrast to the surrounding lowlands, indeed hosting the world's tallest waterfall, Angel Falls (979 meters or 3212 feet). Folded and fractured bedrock structures are distinctive in the topographic pattern.South of the Amazon, the Brazilian Highlands show a mix of

  19. Literacy in South America.

    Science.gov (United States)

    Hornberger, Nancy H.

    1991-01-01

    Literacy in South America must be understood in terms of the linguistic diversity there, where only 2 of 14 nations and territories are monolingual. Oral traditions, standardization of indigenous languages, nonstandard varieties of colonial languages, bilingual education and mother tongue literacy, literacy teaching, and politics are discussed.…

  20. The Hermit Crabs (Crustacea Decapoda, Paguridea) of Northwestern North America

    NARCIS (Netherlands)

    Mclaughlin, P.A.

    1974-01-01

    A systematic study has been made of the Paguridea (exclusive of the Lithodidae) from northwestern North America. In addition to the redescriptions of all known species, two subgenera are herein raised to generic rank and a new genus is described. Several systematic problems have been resolved, and h

  1. South America Geologic Map (geo6ag)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — South America is part of Region 6 (Central and South America) for the World Energy Assessment. The geologic map of South America was digitized so that we could use...

  2. Glaciers of South America

    Science.gov (United States)

    Williams, Richard S.; Ferrigno, Jane G.

    1998-01-01

    Landsat images, together with maps and aerial photographs, have been used to produce glacier inventories, define glacier locations, and study glacier dynamics in the countries of South America, along with the Andes Mountains. In Venezuela, Colombia, Ecuador, and Bolivia, the small glaciers have been undergoing extensive glacier recession since the late 1800's. Glacier-related hazards (outburst floods, mud flows, and debris avalanches) occur in Colombia, in Ecuador, and associated with the more extensive (2,600 km2) glaciers of Peru. The largest area of glacier ice is found in Argentina and Chile, including the northern Patagonian ice field (about 4,200 km2) and the southern Patagonian ice field (about 13,000 km2), the largest glacier in the Southern Hemisphere outside Antarctica.

  3. Subseasonal teleconnections South America - South Africa

    Science.gov (United States)

    Grimm, Alice; Reason, Chris

    2016-04-01

    There is marked subseasonal variability over South America and southern Africa. Based on previous work showing that a teleconnection exists between the South American monsoon system and interannual summer rainfall variability over southern Africa, this study shows teleconnections between subseasonal variability over these landmasses. Observed daily gauge precipitation data for 1970-1999 are gridded to 1° resolution for South America and 2.5° for South Africa. At each grid point, anomalies of daily precipitation are calculated and submitted to a bandpass Lanczos filter to isolate subseasonal oscillations in the 20-90 day band. For each season, the filtered precipitation anomalies for the South African grid boxes are correlated with filtered precipitation anomalies in the grid boxes over South America. Lags from 0 up to 12 days are applied to the South African data, in order to investigate convection anomalies over South America that could produce atmospheric perturbations associated with South African precipitation anomalies. The significance of correlation between the filtered data takes autocorrelation into account and uses effective sample sizes. The results shown represent the best correlations for different climatic regimes such as the winter-rainfall dominated southwestern Cape, the all season rainfall South Coast and the summer-rainfall dominated Limpopo region. NCEP re-analyses are used to composite subseasonal anomalies in OLR, 200 hPa streamfunction, and vertically integrated moisture flux associated with precipitation anomaly above one standard deviation in the filtered series (positive phases) of the South African selected regions. The possible origin of the atmospheric circulation anomalies associated with those positive phases is determined using influence functions (IFs) of a vorticity equation model with a divergence source. The model is linearized about a realistic basic state and includes the divergence of the basic state and the advection of

  4. Breaking away to South America

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    In December 2010, Peter Dreesen of CERN’s Technology Department (TE) returned from a long trip to South America. In four months he traversed the entire Andean range, from the equator to a latitude of 55 degrees south—on a bicycle!   Peter Dreesen on the Salar de Uyuni Lake, Bolivia. 11 000 kilometres is one long bike ride! And yet, that’s what Peter Dreesen did, travelling from Quito, Ecuador to Ushuaia, Argentina. Peter, an engineer in the TE Department, is no novice: the year before, he cycled from Paris to Peking, a distance of 13 500 kilometres, in just over four months. His latest voyage began last August, when he loaded his bicycle and boarded a plane for South America. In the saddle. After a week of acclimatisation at three thousand metres altitude, Peter left Quito on 6 August 2010. He arrived in Ushuaia (el fin del mundo, the end of the world, as it’s known in South America) on 12 December 2010. He recounts: “It was a bizarre sensation...

  5. South America, Shaded Relief and Colored Height

    Science.gov (United States)

    2003-01-01

    This image of South America was generated with data from the Shuttle Radar Topography Mission (SRTM). For this broad view the resolution of the data was first reduced to 30 arcseconds (about 928 meters north-south but variable east-west), matching the best previously existing global digital topographic data set called GTOPO30. The data were then resampled to a Mercator projection with approximately square pixels (about one kilometer, or 0.6 miles, on each side). Even at this decreased resolution the variety of landforms comprising the South American continent is readily apparent.Topographic relief in South America is dominated by the Andes Mountains, which extend all along the Pacific Coast. These mountains are created primarily by the convergence of the Nazca and South American tectonic plates. The Nazca Plate, which underlies the eastern Pacific Ocean, slides under western South America resulting in crustal thickening, uplift, and volcanism. Another zone of plate convergence occurs along the northwestern coast of South America where the Caribbean Plate also slides under the South American Plate and forms the northeastern extension of the Andes Mountains.East of the Andes, much of northern South America drains into the Amazon River, the world's largest river in terms of both watershed area and flow volume. Topographic relief is very low in much of the Amazon Basin but SRTM data provide an excellent detailed look at the basin's three-dimensional drainage pattern, including the geologic structural trough (syncline) that hosts the eastern river channel.North of the Amazon, the Guiana Highlands commonly stand in sharp contrast to the surrounding lowlands, indeed hosting the world's tallest waterfall, Angel Falls (979 meters or 3212 feet). Folded and fractured bedrock structures are distinctive in the topographic pattern.South of the Amazon, the Brazilian Highlands show a mix of landforms, including some broad areas of consistent topographic patterns that indicate the

  6. Impact craters in South America

    CERN Document Server

    Acevedo, Rogelio Daniel; Ponce, Juan Federico; Stinco, Sergio G

    2015-01-01

    A complete and updated catalogue of impact craters and structures in South America from 2014 is presented here. Approximately eighty proven, suspected and disproven structures have been identified by several sources in this continent. All the impact sites of this large continent have been exhaustively reviewed: the proved ones, the possible ones and some very doubtful. Many sites remain without a clear geological ""in situ"" confirmation and some of them could be even rejected. Argentina and Brazil are leading the list containing almost everything detected. In Bolivia, Chile, Colombia, Guyana,

  7. South America Province Boundaries, 1999 (prv6ag)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — South America is part of Region 6 (Central and South America) for the World Energy Assessment. South America was divided into 107 geologic provinces as background...

  8. Adolescent health in South America.

    Science.gov (United States)

    Gaete, Veronica

    2016-08-01

    Since the 1950s, a significant amount of work has been done on behalf of the comprehensive health of young people in South America. This article focuses on the regional process of training health professionals to work with this age group. There are countries in which the growth of adolescent health training has been significant, others that have made progress but still have a narrower offer of teaching activities, and a few where only very basic and limited training is available. Latin American professional associations, scientific societies, and international organizations have also contributed to the education of the adolescent health work force. Although the training in the region has advanced in some countries to the point that there is specialization in adolescent medicine, much remains to be done. Certain regional conditions have contributed to the education of providers in adolescent care. The most important has been the existence of professionals who have been highly motivated to improve the health of young people. They have worked very hard and with great commitment to achieve this goal. There have also been important obstacles to educating professionals in adolescent care. Aside from the usual lack of funding, barriers have existed in the health care system and its providers, as well as the training entities and because of certain South American conditions. Finally, this article describes the regional adolescent medicine programs and the status of recognition of this specialty, and addresses the opportunities and challenges for adolescent health training.

  9. SOUTH AMERICA: INDUSTRIAL ROUNDWOOD SUPPLY POTENTIAL

    Directory of Open Access Journals (Sweden)

    Ronalds W. Gonzalez

    2008-02-01

    Full Text Available South America has substantial potential to expand its forest plantations and raw material supply. From 1997 to 2005, South America had a high annual growth rate in the production of industrial roundwood, with Brazil and Chile being the most important countries. In the same period, Asia had the only negative regional production growth rate in the world, and China became the largest round wood importer in the world. This paper summarizes the status of production, consumption, imports, and exports of industrial roundwood and forest products in South America. Produc-tion and exports from South America have continually increased at annual growth rates exceeding the forestry sector in general and the U.S. in particular. Based on timber growing investments to date, a strong timber production and forest products manufacturing sector has developed in the Southern Cone countries of Chile, Brazil, Argentina, and Uruguay, and is increasing in other countries in Latin America. There will be continued opportunities for forest plantations and new manufacturing facilities throughout South America, tempered somewhat by perceived country financial and political risks. These opportunities will allow South America to increase its share of world production and increase imports to North America and to Asia.

  10. North America and South America (NA-SA) neuropathy project.

    Science.gov (United States)

    Pasnoor, Mamatha; Nascimento, Osvaldo J M; Trivedi, Jaya; Wolfe, Gil I; Nations, Sharon; Herbelin, Laura; de Freitas, M G; Quintanilha, Giseli; Khan, Saud; Dimachkie, Mazen; Barohn, Richard

    2013-08-01

    Peripheral neuropathy is a common neurological disorder. There may be important differences and similarities in the diagnosis of peripheral neuropathy between North America (NA) and South America (SA). Neuromuscular databases were searched for neuropathy diagnosis at two North American sites, University of Kansas Medical Center and University of Texas Southwestern Medical Center, and one South American site, Federal Fluminense University in Brazil. All patients were included into one of the six major categories: immune-mediated, diabetic, hereditary, infectious/inflammatory, systemic/metabolic/toxic (not diabetic) and cryptogenic. A comparison of the number of patients in each category was made between North America and South America databases. Total number of cases in North America was 1090 and in South America was 1034 [immune-mediated: NA 215 (19.7%), SA 191 (18%); diabetic: NA 148 (13.5%), SA 236 (23%); hereditary: NA 292 (26.7%), SA 103 (10%); infectious/inflammatory: NA 53 (4.8%), SA 141 (14%); systemic/metabolic/toxic: NA 71 (6.5%), SA 124 (12%); cryptogenic: NA 311 (28.5%), SA 239 (23%)]. Some specific neuropathy comparisons were hereditary neuropathies [Charcot-Marie-Tooth (CMT) cases] in NA 246/292 (84.2%) and SA 60/103 (58%); familial amyloid neuropathy in SA 31/103 (30%) and none in NA. Among infectious neuropathies, cases of human T-lymphotropic virus type 1 (HTLV-1) neuropathy in SA were 36/141(25%), Chagas disease in SA were 13/141(9%) and none for either in NA; cases of neuropathy due to leprosy in NA were 26/53 (49%) and in SA were 39/141(28%). South American tertiary care centers are more likely to see patients with infectious, diabetic and hereditary disorders such as familial amyloid neuropathies. North American tertiary centers are more likely to see patients with CMT. Immune neuropathies and cryptogenic neuropathies were seen equally in North America and South America.

  11. Climate Projections for South America -discussion of mechanisms

    Science.gov (United States)

    Cavalcanti, Iracema

    2014-05-01

    While temperature is projected to increase, in the future, in the whole South America, with the highest values in central-north areas, precipitation projections show increases or reductions in specific regions. The mechanisms of these changes need to be understood in face of climate change scenarios and possible modifications in the regional meteorological systems behavior. Large areas of South America have a monsoon regime, which shows precipitation differences from winter to summer. Several systems, such as the South Atlantic Convergence Zone (SACZ), the Bolivian High and others, are part of this continental seasonal variability. Tropical areas close to the equator are influenced by the seasonality of the Intertropical Convergence Zone (ITCZ). Other areas at higher latitudes have an extratropical regime, affected by transient synoptic systems, being more uniform during the year. Teleconnections, as ENSO, the Pacific South America (PSA) and the Southern Annular Mode (SAM) affect the variability of the regional systems and precipitation. Ensemble projections of precipitation analyzed in CMIP5 models for the analyzed period of AR5 [(2081-2100)-(1986-2005)]and regional models [(2071-2100)- (1961-1990)] show changes in several areas of South America. Increased precipitation over Southeastern, Northwestern and extreme Southwestern South America, as well as reduced precipitation in Amazonia, Northeast Brazil and Central Chile are projected under scenarios 4.5 and 8.5 by the majority of CMIP5, and regional models downscaled from scenario A1B from CMIP3. The role of changes in SST and in atmospheric circulation in the future projections, which affect the variability of the main systems over South America is discussed. Although there is medium confidence in PSA, SACZ and ITCZ changes, possible changes in the PSA pattern, including the wavetrain centers of action position and intensity, SACZ position and intensity, SAM phase variability and subtropical highs position and

  12. Earthquake swarms in South America

    Science.gov (United States)

    Holtkamp, S. G.; Pritchard, M. E.; Lohman, R. B.

    2011-10-01

    We searched for earthquake swarms in South America between 1973 and 2009 using the global Preliminary Determination of Epicenters (PDE) catalogue. Seismicity rates vary greatly over the South American continent, so we employ a manual search approach that aims to be insensitive to spatial and temporal scales or to the number of earthquakes in a potential swarm. We identify 29 possible swarms involving 5-180 earthquakes each (with total swarm moment magnitudes between 4.7 and 6.9) within a range of tectonic and volcanic locations. Some of the earthquake swarms on the subduction megathrust occur as foreshocks and delineate the limits of main shock rupture propagation for large earthquakes, including the 2010 Mw 8.8 Maule, Chile and 2007 Mw 8.1 Pisco, Peru earthquakes. Also, subduction megathrust swarms commonly occur at the location of subduction of aseismic ridges, including areas of long-standing seismic gaps in Peru and Ecuador. The magnitude-frequency relationship of swarms we observe appears to agree with previously determined magnitude-frequency scaling for swarms in Japan. We examine geodetic data covering five of the swarms to search for an aseismic component. Only two of these swarms (at Copiapó, Chile, in 2006 and near Ticsani Volcano, Peru, in 2005) have suitable satellite-based Interferometric Synthetic Aperture Radar (InSAR) observations. We invert the InSAR geodetic signal and find that the ground deformation associated with these swarms does not require a significant component of aseismic fault slip or magmatic intrusion. Three swarms in the vicinity of the volcanic arc in southern Peru appear to be triggered by the Mw= 8.5 2001 Peru earthquake, but predicted static Coulomb stress changes due to the main shock were very small at the swarm locations, suggesting that dynamic triggering processes may have had a role in their occurrence. Although we identified few swarms in volcanic regions, we suggest that particularly large volcanic swarms (those that

  13. Synchrony in the snowshoe hare cycle in Northwestern North America, 1970-2012

    Science.gov (United States)

    C.J. Krebs; K. Kielland; J.P Bryant; M. O' Donoghue; F. Doyle; C. McIntyre; D. DiFolco; N. Berg; S. Carriere; R. Boonstra; S. Boutin; A. J. Kenney; D. G. Reid; K. Bodony; J. Putera; H. K. Timm; T. Burke.

    2013-01-01

    Snowshoe hares (Lepus americanus Erxleben, 1777) fluctuate in 9–10 year cycles throughout much of their North American range. Regional synchrony has been assumed to be the rule for these cycles, so that hare populations in virtually all of northwestern North America have been assumed to be in phase. We gathered qualitative and quantitative data on...

  14. Improving precipitation simulation from updated surface characteristics in South America

    Science.gov (United States)

    Pereira, Gabriel; Silva, Maria Elisa Siqueira; Moraes, Elisabete Caria; Chiquetto, Júlio Barboza; da Silva Cardozo, Francielle

    2016-04-01

    Land use and land cover maps and their physical-chemical and biological properties are important variables in the numerical modeling of Earth systems. In this context, the main objective of this study is to analyze the improvements resulting from the land use and land cover map update in numerical simulations performed using the Regional Climate Model system version 4 (RegCM4), as well as the seasonal variations of physical parameters used by the Biosphere Atmosphere Transfer Scheme (BATS). In general, the update of the South America 2007 land use and land cover map, used by the BATS, improved the simulation of precipitation by 10 %, increasing the mean temporal correlation coefficient, compared to observed data, from 0.84 to 0.92 (significant at p Pantanal wetlands); (3) in the Northeast region of Brazil; (4) in northwestern Paraguay; and (5) in the River Plate Basin, in Argentina. Moreover, the main precipitation differences between sensitivity and control experiments occurred during the rainy months in central-north South America (October to March). These were associated with a displacement in the South Atlantic convergence zone (SACZ) positioning, presenting a spatial pattern of alternated areas with higher and lower precipitation rates. These important differences occur due to the replacement of tropical rainforest for pasture and agriculture and the replacement of agricultural areas for pasture, scrubland, and deciduous forest.

  15. Imaging of subducted lithosphere beneath South America

    NARCIS (Netherlands)

    Engdahl, E.R.; Hilst, R.D. van der; Berrocal, J.

    1995-01-01

    Tomographic images are produced for the deep structure of the Andean subduction zone beneath western South America. The data used in the imaging are the delay times of P, pP and pwP phases from relocated teleseismic earthquakes in the region. Regionally, structural features larger than about 150 km

  16. Climate Change in Northwestern North America Over the Last Three Centuries

    Science.gov (United States)

    Moore, K.; Holdsworth, G.; Alverson, K.

    2004-05-01

    The relatively short length of most instrumental climate datasets restricts the study of variability that exists in the climate system. This is particularly true regarding the atmosphere where high quality spatially dense data exists only since the late 1940s. With this data, the Pacific North America pattern (PNA) has been identified as one of the dominant modes of variability in the atmosphere. Over this period the PNA has been related to the Pacific Decadal Oscillation (PDO), a mode of climate variability that has been shown to influence marine productivity in the North Pacific as well as modulating the impact of the El Niño-Southern Oscillation in North America. Here we present an updated 301-year ice core record from Mount Logan in northwestern North America that shows a statistically significant and accelerating positive trend in snow accumulation from the middle of the 19th century. A manifestation of this trend has been a warming over northwestern North America that, for much of the 20th century, has been associated with secular changes in the PNA and PDO.

  17. Contemporary Crustal Motion and Deformation of South America Plate

    Institute of Scientific and Technical Information of China (English)

    JIN Shuanggen; ZHU Wenyao

    2003-01-01

    This paper presents the contemporary motion and active deformation of South America plate and relative motion of Nazca-South America plate using space geodetic data. The South America plate is moving at average 14.5 mm/a with an azimuth of 15.2° and shrinking in the west-east at 10. 9 mm/a. The geodetic deformations of sites with respect to the South America plate are in quite good agreement with the estimated deformations from NNR-NUVEL1A, but the deformation of the western South America regions is very large.

  18. Topography over South America from ERS altimetry

    Science.gov (United States)

    Brenner, Anita; Frey, Herb; DiMarzio, John; Tsaoussi, Lucia

    1997-01-01

    The results of the surface topography mapping of South America during the ERS-1 geodetic mission are presented. The altimeter waveforms, the range measurement, and the internal and Doppler range corrections were obtained. The atmospheric corrections and solid tides were calculated. Comparisons between Shuttle laser altimetry and ERS-1 altimetry grid showed good agreement. Satellite radar altimetry data can be used to improve the topographic knowledge of regions for which only poor elevation data currently exist.

  19. Gravity and geoid model for South America

    Science.gov (United States)

    Blitzkow, Denizar; Oliveira Cancoro de Matos, Ana Cristina; do Nascimento Guimarães, Gabriel; Pacino, María Cristina; Andrés Lauría, Eduardo; Nunes, Marcelo; Castro Junior, Carlos Alberto Correia e.; Flores, Fredy; Orihuela Guevara, Nuris; Alvarez, Ruber; Napoleon Hernandez, José

    2016-04-01

    In the last 20 years, South America Gravity Studies (SAGS) project has undertaken an ongoing effort in establishing the fundamental gravity network (FGN); terrestrial, river and airborne relative gravity densifications; absolute gravity surveys and geoid (quasi-geoid) model computation for South America. The old FGN is being replaced progressively by new absolute measurements in different countries. In recent years, Argentina, Bolivia, Brazil, Ecuador, Paraguay and Venezuela organizations participated with relative gravity surveys. Taking advantage of the large amount of data available, GEOID2015 model was developed for 15°N and 57°S latitude and 30 ° W and 95°W longitude based on EIGEN-6C4 until degree and order 200 as a reference field. The ocean area was completed with mean free air gravity anomalies derived from DTU10 model. The short wavelength component was estimated using FFT. The global gravity field models EIGEN-6C4, DIR_R5 were used for comparison with the new model. The new geoid model has been evaluated against 1,319 GPS/BM, in which 592 are located in Brazil and the reminder in other countries. The preliminary RMS difference between GPS/BM and GEOID2015 throughout South America and in Brazil is 46 cm and 17 cm, respectively. New activities are carrying out with the support of the IGC (Geographic and Cartographic Institute) under the coordination of EPUSP/LTG and CENEGEO (Centro de Estudos de Geodesia). The new project aims to establish new gravity points with the A-10 absolute gravimeter in South America. Recent such surveys occurred in São Paulo state, Argentina and Venezuela.

  20. Andes Altiplano, Northwest Argentina, South America

    Science.gov (United States)

    1993-01-01

    This view of the Andes Altiplano in northwest Argentina (25.5S, 68.0W) is dominated by heavily eroded older and inactive volcano peaks. The altiplano is a high altitude cold desert like the Tibetan Plateau but smaller in area. It is an inland extension of the hyperarid Atacama Desert of the west coast of South America and includes hundreds of volcanic edifices (peaks, cinder cones, lava flows, debris fields, lakes and dry lake beds (salars).

  1. Influence of South America orography on summertime precipitation in Southeastern South America

    Science.gov (United States)

    Junquas, C.; Li, L.; Vera, C. S.; Le Treut, H.; Takahashi, K.

    2016-06-01

    Impacts of the main South American orographic structures (the Andes, the Brazilian Plateau and the Guiana shield) on the regional climate and associated global teleconnection are investigated through numerical experiments in which some of these features are suppressed. Simulations are performed with a ``two-way nesting'' system coupling interactively the regional and global versions of the LMDZ4 atmospheric general circulation model. At regional scale, the simulations confirm previous studies, showing that both the Andes and the Brazilian Plateau exert a control on the position and strength of the South Atlantic convergence zone (SACZ), mainly through their impact on the low-level jet and the coastal branch of the subtropical anticyclones. The northern topography of South America appears to be crucial to determine the leading mode of rainfall variability in eastern South America, which manifests itself as a dipole-like pattern between Southeastern South America and the SACZ region. The suppression of South America orography also shows global-scale effects, corresponding to an adjustment of the global circulation system. Changes in atmospheric circulation and precipitation are found in remote areas on the globe, being the consequences of various teleconnection mechanisms. When the Brazilian Plateau and the Andes are suppressed, there is a decrease of precipitation in the SACZ region, associated with a weakening of the large-scale ascendance. Changes are described in terms of anomalies in the Walker circulation, meridional displacements of the mid-latitude jet stream, Southern annular mode anomalies and modifications of Rossby wave train teleconnection processes.

  2. EVOLUTION OF THE PHENOMENON INTEGRATION IN LATIN AMERICA (SOUTH AMERICA

    Directory of Open Access Journals (Sweden)

    EMILIAN M. DOBRESCU

    2013-05-01

    Full Text Available With the end of the Cold War, the creation of a South American economic space has become an important priority of regional powers (Brazil, Argentina, Chile, and the great powers after the war, the U.S. and the European Union (the current name. This integration process has had particular features derived from characteristics of Latin American countries. Multitude of organizations integrative role once again demonstrates the specificity of this process in Latin America to other areas of the world: Africa, Asia, Europe, etc. Contradictory developments phenomenon / Latin American integration process gives substance its characteristic and I will make, probably deeply and future. The purpose of the work and objectives are: know the main features of the phenomenon in Latin American integrationist Objectives: following our vision of a historical phenomenon; brief characterization of the most important Latin American organizations, establishing current and future consequences of integrationist phenomenon in this part of the world.

  3. Catalogue of meteorites from South America

    CERN Document Server

    Acevedo, Rogelio Daniel; García, Víctor Manuel

    2014-01-01

    The first Catalogue of Meteorites from South America includes new specimens never previously reported, while doubtful cases and pseudometeorites have been deliberately omitted.The falling of these objects is a random event, but the sites where old meteorites are found tend to be focused in certain areas, e.g. in the deflation surfaces in Chile's Atacama Desert, due to favorable climate conditions and ablation processes.Our Catalogue provides basic information on each specimen like its provenance and the place where it was discovered (in geographic co-ordinates and with illustrative maps), its

  4. The palms of South America: diversity, distribution and evolutionary history

    Directory of Open Access Journals (Sweden)

    Jean-Christophe Pintaud

    2014-03-01

    Full Text Available This article presents an inventory of South American palms including 457 species and 50 genera. The distribution of palms within seven phytogeographical entities is analyzed. Factors which influence the evolution of palms in South America are discussed.

  5. Mantle Structure Beneath Central South America

    Science.gov (United States)

    Vandecar, J. C.; Silver, P. G.; James, D. E.; Assumpcao, M.; Schimmel, M.; Zandt, G.

    2003-12-01

    Making use of 60 digital broadband seismic stations that have operated across central South America in recent years, we have undertaken an inversion for the upper- and uppermost lower-mantle P- and S-wave velocity structures beneath the region. We have combined data from four portable PASSCAL-type experiments as well as the 3 GTSN permanent stations (LPAZ, BDFB and CPUP) and 1 Geoscope station (SPB) located in the region. The portable data were deployed at various times between 1992 and 1999 and include: 28 sites from the Brazilian Lithosphere Seismic Project (BLSP: Carnegie Institution of Washington and Universidade de Sao Paulo), 16 sites from the Broadband ANdean JOint experiment (BANJO: Carnegie Institution of Washington and University of Arizona), 8 sites from the Seismic Exploration of the Deep Altiplano project (SEDA: Lawrence Livermore National Laboratory) and 4 sites from the University of Brasilia. The P- and S-wave relative delay times are independently obtained via a multi-channel cross correlation of band-passed waveforms for each teleseismic event. These data are then inverted using an iterative, robust, non-linear scheme which parameterizes the 3-D velocity variations as splines under tension constrained at over 120,000 nodes across South America between latitudes of 15 and 30 degrees South. Amongst other features, we robustly image the high-velocity subducting Nazca plate penetrating into the lower mantle and the high-velocity root of the ~3.2 Gyr old Sao Francisco Craton extending to depths of 200-300 km. We will discuss the consistency between our tomographic models and predictions of dynamic mantle models based on plate tectonic reconstructions of subduction.

  6. Hermann Karsten, pioneer of geologic mapping in northwestern South America

    Science.gov (United States)

    Aalto, K. R.

    2015-06-01

    In the late 19th century, a regional map of Nueva Granada (present-day Colombia, Panama and parts of Venezuela and Ecuador) was published by German botanist and geologist Hermann Karsten (1817-1908). Karsten's work was incorporated by Agustín Codazzi (1793-1859), an Italian who emigrated to Venezuela and Colombia to serve as a government cartographer and geographer, in his popular Atlas geográfico e histórico de la Republica de Colombia (1889). Geologic mapping and most observations provided in this 1889 atlas were taken from Karsten's Géologie de l'ancienne Colombie bolivarienne: Vénézuela, Nouvelle-Grenade et Ecuador (1886), as cited by Manual Paz and/or Felipe Pérez, who edited this edition of the atlas. Karsten defined four epochs in Earth history: Primera - without life - primary crystalline rocks, Segunda - with only marine life - chiefly sedimentary rocks, Tercera - with terrestrial quadrupeds and fresh water life forms life - chiefly sedimentary rocks, and Cuarta - mankind appears, includes diluvial (glacigenic) and post-diluvial terranes. He noted that Colombia is composed of chiefly of Quaternary, Tertiary and Cretaceous plutonic, volcanic and sedimentary rocks, and that Earth's internal heat (calor central) accounted, by escape of inner gases, for volcanism, seismicity and uplift of mountains. Karsten's regional mapping and interpretation thus constitutes the primary source and ultimate pioneering geologic research.

  7. Alien conifer invasions in South America: short fuse burning?

    CSIR Research Space (South Africa)

    Richardson, DM

    2007-01-01

    Full Text Available conifers has a much shorter history in South America, and invasions are a recent phenomenon. A workshop was convened in Argentina in May 2007 to discuss the rapid emergence of problems with invasive conifers in South America. Workshop delegates agreed that...

  8. CRED Gridded Bathymetry near South Pioneer Bank (100-003), Northwestern Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — File 100-003b is a 60-m ASCII grid of depth data collected near south Pioneer Bank in the Northwestern Hawaiian Islands as of May 2003. This grid has been produced...

  9. CRED Gridded Bathymetry near South Maro Reef (100-008), Northwestern Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — File 100-008b is a 60-m ASCII grid of depth data collected near south Maro Reef in the Northwestern Hawaiian Islands as of May 2003. This grid has been produced as...

  10. Improving precipitation simulation from updated surface characteristics in South America

    Science.gov (United States)

    Pereira, Gabriel; Silva, Maria Elisa Siqueira; Moraes, Elisabete Caria; Chiquetto, Júlio Barboza; da Silva Cardozo, Francielle

    2017-07-01

    Land use and land cover maps and their physical-chemical and biological properties are important variables in the numerical modeling of Earth systems. In this context, the main objective of this study is to analyze the improvements resulting from the land use and land cover map update in numerical simulations performed using the Regional Climate Model system version 4 (RegCM4), as well as the seasonal variations of physical parameters used by the Biosphere Atmosphere Transfer Scheme (BATS). In general, the update of the South America 2007 land use and land cover map, used by the BATS, improved the simulation of precipitation by 10 %, increasing the mean temporal correlation coefficient, compared to observed data, from 0.84 to 0.92 (significant at p < 0.05, Student's t test). Correspondingly, the simulations performed with adjustments in maximum fractional vegetation cover, in visible and shortwave infrared reflectance, and in the leaf area index, showed a good agreement for maximum and minimum temperature, with values closer to observed data. The changes in physical parameters and land use updating in BATS/RegCM4 reduced overestimation of simulated precipitation from 19 to 7 % (significant at p < 0.05, Student's t test). Regarding evapotranspiration and precipitation, the most significant differences due to land use updating were located (1) in the Amazon deforestation arc; (2) around the Brazil-Bolivia border (in the Brazilian Pantanal wetlands); (3) in the Northeast region of Brazil; (4) in northwestern Paraguay; and (5) in the River Plate Basin, in Argentina. Moreover, the main precipitation differences between sensitivity and control experiments occurred during the rainy months in central-north South America (October to March). These were associated with a displacement in the South Atlantic convergence zone (SACZ) positioning, presenting a spatial pattern of alternated areas with higher and lower precipitation rates. These important differences occur due to the

  11. Holocene glacial fluctuations in southern South America

    Science.gov (United States)

    Reynhout, S.; Sagredo, E. A.; Kaplan, M. R.; Aravena, J. C.; Martini, M. A.; Strelin, J. A.; Schaefer, J. M.

    2016-12-01

    Understanding the timing and magnitude of former glacier fluctuations is critical to decipher long-term climatic trends and to unravel both natural cycles and human impact on the current glacial behavior. Despite more than seven decades of research efforts, a unifying model of Holocene glacial fluctuations in Southern South America remains elusive. Here, we present the state-of-the-art regarding the timing of Holocene glacial fluctuation in southern Patagonia-Tierra del Fuego, with a focus on a new generation of high-resolution radiocarbon and 10Be surface exposure dating chronologies. Recently acquired evidence suggest that after receding from advanced Late Glacial positions, Patagonian glaciers were for the most part close to, or even behind, present ice margins during the Early Holocene. On the other hand, emerging chronologies indicate that in some areas there were extensive expansions (century scale?) that punctuated the warm interval. Subsequently, we have evidence of multiple millennial timescale glacial advances starting in the middle Holocene. Several glacial maxima are defined by moraines and other landforms from 7000 years ago to the 19th century, with a gap sometime between 4,500 and 2,500 years ago. The last set of advances began around 800-600 years ago. Although glacial activity is documented in Patagonia at the same time as the European Little Ice Age, the extent of these glacial events are less prominent than those of the mid-Holocene. The causes that may explain these glacial fluctuations remain elusive. Finally, we discuss ongoing efforts to better define the timing and extent of Holocene glaciations in southern South America, and to establish the basis to test competing hypothesis of regional Holocene climate variability.

  12. A Paleoecological View of the Anthropocene in Tropical South America

    Science.gov (United States)

    Bush, M. B.; McMichael, C. H.; Piperno, D. R.

    2015-12-01

    Many potential events could define the onset of the Anthropocene in the Neotropics. The first effects caused by humans included the final extinction of megafauna around 10,000 years ago, and changes in fire frequency, particularly after about 8000 years ago. The first agriculture (squash) is evident in northwestern regions at 9000 BP, and in the Amazon Basin maize is cultivated by 6300 BP. But these events have not been widely documented on the continent and if some chronological uniformity is sought as a guide to defining the onset of the Anthropocene, they would fail that test. Coming forward through time, increasing societal complexity is evident beginning about 3000 BP in both the Amazon and the Andes, but again the development was patchy. Some archaeologists are arguing that between c. 2000 BP and 500 BP the Amazon Basin became a manufactured landscape. While major river corridors were very likely influenced by human populations, the level of use in the great interfluvial areas (c. 90% of Amazonia) remains a matter of debate. The empirical data that exist for human presence in these areas point to sparse occupation, both in space and time, and the assertion that most of prehistoric Amazonia was manipulated by humans is unsupported. Following European contact, indigenous populations were reduced probably 90-95% within 200 years, which interrupted the cultural trajectory of the Neotropics. The next possible contender for the local onset of the Anthropocene was the Rubber Boom (1879-1912). The Rubber Boom greatly increased human populations along many of the Amazon's major rivers and tributaries. Hunting and deforestation picked up pace, and the growing presence of steamships allowed exportation of a wide range of Amazonian products beyond rubber, e.g. plumes, timber, and turtle oil. In addition to these local effects, the global effects that came with increased fossil fuel use and industrialization, would also have influenced all of South America. Even so, the

  13. Global evolution of Equidae and Gomphotheriidae from South America.

    Science.gov (United States)

    Prado, José L; Alberdi, María T

    2014-08-01

    The contemporary South American mammalian communities were determined by the emergence of the Isthmus of Panama and by the profound climatic oscillations during the Pleistocene. Horses and gomphotheres were 2 very conspicuous groups of immigrant mammals from North America that arrived in South America during the Pleistocene. The present study compiles updated data on the phylogeny, systematics and ecology of both groups in South America. The horses in South America are represented by 2 genera, Hippidion and Equus, as are the gomphotheres, represented by Cuvieronius and Stegomastodon. Both genera of horses include small (Hippidion devillei, H. saldiasi, E. andium and E. insulatus) and large forms (Equus neogeus and H. principale), which dispersed into South America using 2 different routes. The possible model for this dispersion indicates that the small forms used the Andes corridor, while larger horses dispersed through the eastern route and through some coastal areas. In the case of gomphotheres, Cuvieronius and Stegomastodon reached South America in 2 independent dispersal events, and Cuvieronius dispersed across the Andean corridor, while large Stegomastodon spread along the eastern route. Horses and gomphotheres present values of δ(13) C from woodlands to C4 grasslands. Hippidion present lower values of δ(13) C than Equus in the late Pleistocene, whereas the gomphotheres diverge from value of δ(18) O, reflecting that Cuvieronius inhabited the Andean corridor and Stegomastodon dispersed through eastern plains. The gomphothere and horse species recorded in South America became extinct around the time that humans arrived.

  14. Feline Immunodeficiency Virus in South America

    Directory of Open Access Journals (Sweden)

    Bruno M. Teixeira

    2012-03-01

    Full Text Available The rapid emergence of AIDS in humans during the period between 1980 and 2000 has led to extensive efforts to understand more fully similar etiologic agents of chronic and progressive acquired immunodeficiency disease in several mammalian species. Lentiviruses that have gene sequence homology with human immunodeficiency virus (HIV have been found in different species (including sheep, goats, horses, cattle, cats, and several Old World monkey species. Lentiviruses, comprising a genus of the Retroviridae family, cause persistent infection that can lead to varying degrees of morbidity and mortality depending on the virus and the host species involved. Feline immunodeficiency virus (FIV causes an immune system disease in domestic cats (Felis catus involving depletion of the CD4+ population of T lymphocytes, increased susceptibility to opportunistic infections, and sometimes death. Viruses related to domestic cat FIV occur also in a variety of nondomestic felids. This is a brief overview of the current state of knowledge of this large and ancient group of viruses (FIVs in South America.

  15. Climate predictability and prediction skill on seasonal time scales over South America from CHFP models

    Science.gov (United States)

    Osman, Marisol; Vera, C. S.

    2016-11-01

    This work presents an assessment of the predictability and skill of climate anomalies over South America. The study was made considering a multi-model ensemble of seasonal forecasts for surface air temperature, precipitation and regional circulation, from coupled global circulation models included in the Climate Historical Forecast Project. Predictability was evaluated through the estimation of the signal-to-total variance ratio while prediction skill was assessed computing anomaly correlation coefficients. Both indicators present over the continent higher values at the tropics than at the extratropics for both, surface air temperature and precipitation. Moreover, predictability and prediction skill for temperature are slightly higher in DJF than in JJA while for precipitation they exhibit similar levels in both seasons. The largest values of predictability and skill for both variables and seasons are found over northwestern South America while modest but still significant values for extratropical precipitation at southeastern South America and the extratropical Andes. The predictability levels in ENSO years of both variables are slightly higher, although with the same spatial distribution, than that obtained considering all years. Nevertheless, predictability at the tropics for both variables and seasons diminishes in both warm and cold ENSO years respect to that in all years. The latter can be attributed to changes in signal rather than in the noise. Predictability and prediction skill for low-level winds and upper-level zonal winds over South America was also assessed. Maximum levels of predictability for low-level winds were found were maximum mean values are observed, i.e. the regions associated with the equatorial trade winds, the midlatitudes westerlies and the South American Low-Level Jet. Predictability maxima for upper-level zonal winds locate where the subtropical jet peaks. Seasonal changes in wind predictability are observed that seem to be related to

  16. Why Do the Boreal Forest Ecosystems of Northwestern Europe Differ from Those of Western North America?

    Science.gov (United States)

    Boonstra, Rudy; Andreassen, Harry P.; Boutin, Stan; Hušek, Jan; Ims, Rolf A.; Krebs, Charles J.; Skarpe, Christina; Wabakken, Petter

    2016-01-01

    Abstract The boreal forest is one of the largest terrestrial biomes on Earth. Conifers normally dominate the tree layer across the biome, but other aspects of ecosystem structure and dynamics vary geographically. The cause of the conspicuous differences in the understory vegetation and the herbivore–predator cycles between northwestern Europe and western North America presents an enigma. Ericaceous dwarf shrubs and 3– to 4-year vole–mustelid cycles characterize the European boreal forests, whereas tall deciduous shrubs and 10-year snowshoe hare–lynx cycles characterize the North American ones. We discuss plausible explanations for this difference and conclude that it is bottom-up: Winter climate is the key determinant of the dominant understory vegetation that then determines the herbivore–predator food-web interactions. The crucial unknown for the twenty-first century is how climate change and increasing instability will affect these forests, both with respect to the dynamics of individual plant and animal species and to their community interactions. PMID:28533563

  17. Late-glacial of southern South America

    Science.gov (United States)

    Heusser, C. J.

    Overall trends in late-glacial paleoenvironments of southern South America are interpretable from the pollen stratigraphy of radiocarbon dated sections of mires in Tierra del Fuego (55°S), the Chilotan archipelago (42-43°S), and the Chilean Lake District (39-41°S). In Tierra del Fuego, southern beech ( Nothofagus) and shrub and herb taxa (Gramineae, Empetrum, Acaena, Gunnera, Compositae and Cyperaceae) serve as indicators of the changing climate; in the Chilotan archipelago and in the Chilean Lake District, southern beech and other trees (species of Myrtaceae, Podocarpus, Prumnopitys, Pseudopanax and Weinmannia) suffice as indices of climatic change. Pollen records from each of these regions, although in need of greater dating control, indicate climatic sequences that are broadly similar. The records, however, are not regionally consistent in all aspects and differ in their indicator value with the implication of fossil beetle evidence. Attempts at correlation can be unsatisfactory at times and can stem inter alia from the different ecophysiological responses of both plants and beetles to environmental pressures. These differences, which affect the timing of reproduction and migration, may result in the variable occurrence of different species in the records. The broad implication of the pollen data is that following a glacial readvance culminating at about 15,000-14,500 BP, late-glacial climate was generally warmer during intervals before 13,000 and between 12,000 and 11,000 BP, and was cooler between 13,000 and 12,000 and from 11,000 to 10,000 BP.

  18. New views on American colonization: critical tests from South America

    Directory of Open Access Journals (Sweden)

    O'Rourke, Dennis

    2007-01-01

    Full Text Available The traditional view of colonization of the Americas as a migration across Beringia and subsequent dispersal southward following the last glacial maximum is being increasingly questioned. In North America, archaeological links to Siberia are tenuous and genetic data are more consistent with an earlier entry of people into the Americas, from Central rather than Northeast Siberia. An entry of populations into the Americas prior to the last glacial maximum forces a reconsideration not only of timing, but also geographic points of entry and speed of dispersal, based on ecological theory. A number of emerging alternative hypotheses on the colonization of the Americas predict early entry and dispersal of people into South America - earlier than, or coeval with, initial dispersal in North America. The study of genetic, morphological, and archaeological variation across South America is critical to testing these new, alternative hypotheses of Native American origins. I will review the evidence for emerging, alternative views of American Colonization, and suggest ways in which data from South American populations and prehistory will be crucial in testing them.

  19. [Health system reforms in South America: an opportunity for UNASUR].

    Science.gov (United States)

    Gomes-Temporão, José; Faria, Mariana

    2014-01-01

    Health systems in South America still support segmentation, privatization and fragmentation. Health reforms of the structural adjustment programs in the 1980s and 1990s in South America followed different purposes and strategies ranging from privatization, commodification and state intervention for the implementation of a national public health service with universal access as a right of the citizens. Since the 2000s, many countries have expanded social policies, reduced poverty and social inequalities, and improved access to healthcare. This article proposes to discuss the health systems in South America from historical and political backgrounds, and the progress from the reforms in the last three decades. It also presents the three paradigmatic models of reform and their evolution, as well as the contrasts between universal coverage and universal systems. Finally, it presents current strengths and weaknesses of the twelve South American health systems as well as current opportunities and challenges in health for UNASUR.

  20. Of glaciers and refugia: a decade of study sheds new light on the phylogeography of northwestern North America.

    Science.gov (United States)

    Shafer, Aaron B A; Cullingham, Catherine I; Côté, Steeve D; Coltman, David W

    2010-11-01

    Glacial cycles have played a dominant role in shaping the genetic structure and distribution of biota in northwestern North America. The two major ice age refugia of Beringia and the Pacific Northwest were connected by major mountain chains and bordered by the Pacific Ocean. As a result, numerous refugial options were available for the regions taxa during glacial advances. We reviewed the importance of glaciations and refugia in shaping northwestern North America's phylogeographic history. We also tested whether ecological variables were associated with refugial history. The recurrent phylogeographic patterns that emerged were the following: (i) additional complexity, i.e. refugia within refugia, in both Beringia and the Pacific Northwest; and (ii) strong evidence for cryptic refugia in the Alexander Archipelago and Haida Gwaii, the Canadian Arctic and within the ice-sheets. Species with contemporary ranges that covered multiple refugia, or those with high dispersal ability, were significantly more likely to have resided in multiple refugia. Most of the shared phylogeographic patterns can be attributed to multiple refugial locales during the last glacial maximum or major physiographic barriers like rivers and glaciers. However, some of the observed patterns are much older and appear connected to the orogeny of the Cascade-Sierra chain or allopatric differentiation during historic glacial advances. The emergent patterns from this review suggest we should refine the classic Beringian-southern refugial paradigm for northwestern North American biota and highlight the ecological and evolutionary consequences of colonization from multiple refugia.

  1. Reconstruction of paleocoastlines for the northwestern South China Sea since the Last Glacial Maximum

    Institute of Scientific and Technical Information of China (English)

    YAO YanTao; HARFF Jan; MEYER Michael; ZHAN WenHuan

    2009-01-01

    The range of relative sea level rise in the northwestern South China Sea since the Last Glacial Maximum was over 100 m. As a result, lowland regions including the Northeast Vietnam coast, Beibu Gulf, and South China coast experienced an evolution from land to sea. Based on the principle of recon structing paleogeography and using recent digital elevation model, relative sea level curves, and sediment accumulation data, this paper presents a series of paleogeographic scenarios back to 20 cal. ka BP for the northwestern South China Sea. The scenarios demonstrate the entire process of coastline changes for the area of interest. During the late glacial period from 20 to 15 cal. ka BP, coastline slowly retreated, causing a land loss of only 1 ×104 km2, and thus the land-sea distribution remained nearly unchanged. Later in 15--10 cal. ka BP coastline rapidly retreated and area of land loss was up to 24×104 km2, causing lowlands around Northeast Vietnam and South China soon to be underwater. Coastline retreat continued quite rapidly during the early Holocene. From 10 to 6 cal. ka BP land area had decreased by 9×104 km2, and during that process the Qiongzhou Strait completely opened up. Since the mid Holocene, main controls on coastline change are from vertical crustal movements and sedimentation. Transgression was surpassed by regression, resulting in a land accretion of about 10×104 km2.

  2. Reconstruction of paleocoastlines for the northwestern South China Sea since the Last Glacial Maximum

    Institute of Scientific and Technical Information of China (English)

    HARFF; Jan; MEYER; Michael

    2009-01-01

    The range of relative sea level rise in the northwestern South China Sea since the Last Glacial Maximum was over 100 m. As a result, lowland regions including the Northeast Vietnam coast, Beibu Gulf, and South China coast experienced an evolution from land to sea. Based on the principle of reconstructing paleogeography and using recent digital elevation model, relative sea level curves, and sediment accumulation data, this paper presents a series of paleogeographic scenarios back to 20 cal. ka BP for the northwestern South China Sea. The scenarios demonstrate the entire process of coastline changes for the area of interest. During the late glacial period from 20 to 15 cal. ka BP, coastline slowly retreated, causing a land loss of only 1×104 km2, and thus the land-sea distribution remained nearly unchanged. Later in 15-10 cal. ka BP coastline rapidly retreated and area of land loss was up to 24×104 km2, causing lowlands around Northeast Vietnam and South China soon to be underwater. Coastline retreat continued quite rapidly during the early Holocene. From 10 to 6 cal. ka BP land area had decreased by 9×104 km2, and during that process the Qiongzhou Strait completely opened up. Since the mid Holocene, main controls on coastline change are from vertical crustal movements and sedimentation. Transgression was surpassed by regression, resulting in a land accretion of about 10×104 km2.

  3. Climate change and American Bullfrog invasion: what could we expect in South America?

    Directory of Open Access Journals (Sweden)

    Javier Nori

    Full Text Available BACKGROUND: Biological invasion and climate change pose challenges to biodiversity conservation in the 21(st century. Invasive species modify ecosystem structure and functioning and climatic changes are likely to produce invasive species' range shifts pushing some populations into protected areas. The American Bullfrog (Lithobates catesbeianus is one of the hundred worst invasive species in the world. Native from the southeast of USA, it has colonized more than 75% of South America where it has been reported as a highly effective predator, competitor and vector of amphibian diseases. METHODOLOGY/PRINCIPAL FINDINGS: We modeled the potential distribution of the bullfrog in its native range based on different climate models and green-house gases emission scenarios, and projected the results onto South America for the years of 2050 and 2080. We also overlaid projected models onto the South American network of protected areas. Our results indicate a slight decrease in potential suitable area for bullfrog invasion, although protected areas will become more climatically suitable. Therefore, invasion of these sites is forecasted. CONCLUSION/SIGNIFICANCE: We provide new evidence supporting the vulnerability of the Atlantic Forest Biodiversity Hotspot to bullfrog invasion and call attention to optimal future climatic conditions of the Andean-Patagonian forest, eastern Paraguay, and northwestern Bolivia, where invasive populations have not been found yet. We recommend several management and policy strategies to control bullfrog invasion and argue that these would be possible if based on appropriate articulation among government agencies, NGOs, research institutions and civil society.

  4. Crustal structure and extension mode in the northwestern margin of the South China Sea

    Science.gov (United States)

    Gao, Jinwei; Wu, Shiguo; McIntosh, Kirk; Mi, Lijun; Liu, Zheng; Spence, George

    2016-06-01

    Combining multi-channel seismic reflection and gravity modeling, this study has investigated the crustal structure of the northwestern South China Sea margin. These data constrain a hyper-extended crustal area bounded by basin-bounding faults corresponding to an aborted rift below the Xisha Trough with a subparallel fossil ridge in the adjacent Northwest Sub-basin. The thinnest crust is located in the Xisha Trough, where it is remnant lower crust with a thickness of less than 3 km. Gravity modeling also revealed a hyper-extended crust across the Xisha Trough. The postrift magmatism is well developed and more active in the Xisha Trough and farther southeast than on the northwestern continental margin of the South China Sea; and the magmatic intrusion/extrusion was relatively active during the rifting of Xisha Trough and the Northwest Sub-basin. A narrow continent-ocean transition zone with a width of ˜65 km bounded seaward by a volcanic buried seamount is characterized by crustal thinning, rift depression, low gravity anomaly and the termination of the break-up unconformity seismic reflection. The aborted rift near the continental margin means that there may be no obvious detachment fault like that in the Iberia-Newfoundland type margin. The symmetric rift, extreme hyper-extended continental crust and hotter mantle materials indicate that continental crust underwent stretching phase (pure-shear deformation), thinning phase and breakup followed by onset of seafloor spreading and the mantle-lithosphere may break up before crustal-necking in the northwestern South China Sea margin.

  5. Crustal activities recorded in coral reefs in the northwestern South China Sea

    Institute of Scientific and Technical Information of China (English)

    ZHAN Wenhuan; YAO Yantao; ZHANG Zhiqiang; SUN Zongxun; ZHAN Meizhen; SUN Longtao; LIU Zaifeng

    2006-01-01

    Coral reefs in the northwest of South China Sea have recorded the information from not only the environmental variation but also the crustal activities there during their development. The main crustal activities correlated with the coral reef development include fault, seismic, and volcano activities,etc. The high-resolution spark seismic profiles in the northwestern South China Sea show that the fault activities in the coral reef region have been clearly recorded, and appear as neonatal faults incising reefs. Earthquakes in the coral reef region are rather intense, especially the two occurring on December,31, 1994, and January, 10, 1995, around the southwest of Leizhou Peninsula, with the magnitude of 6.1and 6.2, respectively. They have great influence on the growth of the local coral reefs. Quaternary volcanos are active in the northwestern South China Sea, especially around the southwest of Leizhou Peninsula, and they have obvious control of the coral reef development. Some submarine volcanoes form the substrates of coral reef, while a few emerge above the sea surface and form coral islands.

  6. Measuring the new world enlightenment science and South America

    CERN Document Server

    Safier, Neil

    2008-01-01

    Prior to 1735, South America was terra incognita to many Europeans. But that year, the Paris Academy of Sciences sent a mission to the Spanish American province of Quito (in present-day Ecuador) to study the curvature of the earth at the Equator. Equipped with quadrants and telescopes, the mission's participants referred to the transfer of scientific knowledge from Europe to the Andes as a "sacred fire" passing mysteriously through European astronomical instruments to observers in South America. By taking an innovative interdisciplinary look at the traces of this expedition, Measuring the New

  7. Tierra del Fuego, Argentina, South America

    Science.gov (United States)

    1991-01-01

    The Mitre Peninsula is the easternmost tip of Tierra del Fuego, Argentina, (54.5S, 65.5W). Early winter snow can be seen on this south tip of the Andes Mountains. These same mountains continue underwater to Antarctica. The Strait of Magellan, separating the South American mainland from Tierra del Fuego is off the scene to the north and west, but the Strait of LeMaire, separating Tierra del Fuego from the Isla de los Estados can be seen.

  8. New species of Ficus (Moraceae) from South America

    NARCIS (Netherlands)

    Berg, C.C.

    2007-01-01

    Eleven new species and one new subspecies of Ficus from South America, mainly from the Andean region, are described and illustrated: F. cotopaxiensis, F. ecuadorensis, F. francoae, F. jacobii subsp. mantana, F. loxensis, F. maximoides, F. pastasana, F. quichuana, F. quistocochensis, F. rimacana, F.

  9. New species of Ficus (Moraceae) from South America

    NARCIS (Netherlands)

    Berg, C.C.

    2007-01-01

    Eleven new species and one new subspecies of Ficus from South America, mainly from the Andean region, are described and illustrated: F. cotopaxiensis, F. ecuadorensis, F. francoae, F. jacobii subsp. mantana, F. loxensis, F. maximoides, F. pastasana, F. quichuana, F. quistocochensis, F. rimacana, F.

  10. Patterns of species richness in sandy beaches of South America

    African Journals Online (AJOL)

    Species richness of the intertidal macroinfauna of exposed sandy beaches around South America is reviewed in relation ... The middle shore is prim

  11. New species of Ficus (Moraceae) from South America

    OpenAIRE

    C.C. Berg

    2007-01-01

    Eleven new species and one new subspecies of Ficus from South America, mainly from the Andean region, are described and illustrated: F. cotopaxiensis, F. ecuadorensis, F. francoae, F. jacobii subsp. mantana, F. loxensis, F. maximoides, F. pastasana, F. quichuana, F. quistocochensis, F. rimacana, F. sumacoana, and F. valaria. Ficus malacocarpa Standl. is reduced to a subspecies of F. popenoei Standl.

  12. Range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) in northwestern North America

    Science.gov (United States)

    Funk, W.C.; Pearl, C.A.; Draheim, H.M.; Adams, M.J.; Mullins, T.D.; Haig, S.M.

    2008-01-01

    The dynamic geological and climatic history of northwestern North America has made it a focal region for phylogeography. We conducted a range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) across its range in northwestern North America to understand its evolutionary history and the distribution of clades to inform conservation of R. pretiosa and Great Basin R. luteiventris, candidates for listing under the US Endangered Species Act. Mitochondrial DNA sequence data from a segment of the cytochrome b gene were obtained from 308 R. luteiventris and R. pretiosa from 96 sites. Phylogenetic analysis revealed one main R. pretiosa clade and three main R. luteiventris clades, two of which overlapped in southeastern Oregon. The three R. luteiventris clades were separated from each other by high levels of sequence divergence (average of 4.75-4.97%). Two divergent clades were also uncovered within the Great Basin. Low genetic variation in R. pretiosa and the southeastern Oregon clade of R. luteiventris suggests concern about their vulnerability to extinction. ?? 2008 Elsevier Inc.

  13. The Influence of Nationalism in Mercosur and in South America - can the regional integration project survive?

    DEFF Research Database (Denmark)

    Christensen, Steen Fryba

    2007-01-01

    The article discusses if the tendency towards nationalism in Latin America seems to get in the way of the regional integration project in Mercosur and at the level of South America......The article discusses if the tendency towards nationalism in Latin America seems to get in the way of the regional integration project in Mercosur and at the level of South America...

  14. The Influence of Nationalism in Mercosur and in South America - can the regional integration project survive?

    DEFF Research Database (Denmark)

    Christensen, Steen Fryba

    2007-01-01

    The article discusses if the tendency towards nationalism in Latin America seems to get in the way of the regional integration project in Mercosur and at the level of South America......The article discusses if the tendency towards nationalism in Latin America seems to get in the way of the regional integration project in Mercosur and at the level of South America...

  15. Contextualizing the trauma experience of women immigrants from Central America, South America, and Mexico.

    Science.gov (United States)

    Kaltman, Stacey; Hurtado de Mendoza, Alejandra; Gonzales, Felisa A; Serrano, Adriana; Guarnaccia, Peter J

    2011-12-01

    Trauma has been understudied among Latina immigrants from Central and South America. This study examined the types and context of trauma exposure experienced by immigrant women from Central America, South America, and Mexico living in the United States. Twenty-eight women seeking care in primary care or social service settings completed life history interviews. The majority of the women reported some type of trauma exposure in their countries of origin, during immigration, and/or in the United States. In the interviews, we identified types of trauma important to the experience of these immigrants that are not queried by trauma assessments typically used in the United States. We also identified factors that are likely to amplify the impact of trauma exposure. The study highlights the importance of utilizing a contextualized approach when assessing trauma exposure among immigrant women.

  16. Preliminary report on osteochondrosis in cattle in the north-western parts of South Africa

    Directory of Open Access Journals (Sweden)

    Leon Prozesky

    2016-03-01

    Full Text Available The north-western part of South Africa, in particular, is well known for mineral imbalances. Aphosphorosis, resulting in rickets and osteomalacia, received a lot of attention at the turn of the nineteenth century (1882–1912. This was followed in 1997 by research on Vryburg hepatosis, another area-specific mineral imbalance–related disease in young calves reared on manganese-rich soil derived from the weathering of dolomitic (carbonate rock formations. In 1982, a totally new syndrome (osteochondrosis manifested in, amongst others, areas in South Africa where aphosphorosis was rife. Osteochondrosis was also identified in the south-western parts of Namibia as well as southern Botswana and other areas in South Africa. Osteochondrosis has a multifactorial aetiology and this study focused on the role of minerals, particularly phosphorus, in the development of the disease. A significant improvement in the clinical signs in experimental animals and a reduction of osteochondrosis occurred on farms where animals received bioavailable trace minerals and phosphorus as part of a balanced lick. An increase in the occurrence of the disease on farms during severe drought conditions in 2012–2013 prompted researchers to investigate the possible role of chronic metabolic acidosis in the pathogenesis of the disease.

  17. Seismic Wave Propagation in South America,

    Science.gov (United States)

    1995-08-14

    3.41 0.284 80 20.0 7.90 4.34 3.43 0.284 80 Recommendations and Future Plans We have recently obtained the Mapa Neotect6nico de Venezuela (Beltran, 1993...South American plate nor the Caribe plate, but is part of the bloque Andino (Ramirez, 1977; Pennington, 1981). We plan to continue to model by the two...CD/1254, Ginebra. Conferencia de Desarme (1994b). Informe a la Conferencia de Desarme sobre los Trabajos Realizados por el Grupo ad Hoc de Expertos

  18. Post-invasion demography of prehistoric humans in South America.

    Science.gov (United States)

    Goldberg, Amy; Mychajliw, Alexis M; Hadly, Elizabeth A

    2016-04-14

    As the last habitable continent colonized by humans, the site of multiple domestication hotspots, and the location of the largest Pleistocene megafaunal extinction, South America is central to human prehistory. Yet remarkably little is known about human population dynamics during colonization, subsequent expansions, and domestication. Here we reconstruct the spatiotemporal patterns of human population growth in South America using a newly aggregated database of 1,147 archaeological sites and 5,464 calibrated radiocarbon dates spanning fourteen thousand to two thousand years ago (ka). We demonstrate that, rather than a steady exponential expansion, the demographic history of South Americans is characterized by two distinct phases. First, humans spread rapidly throughout the continent, but remained at low population sizes for 8,000 years, including a 4,000-year period of 'boom-and-bust' oscillations with no net growth. Supplementation of hunting with domesticated crops and animals had a minimal impact on population carrying capacity. Only with widespread sedentism, beginning ~5 ka, did a second demographic phase begin, with evidence for exponential population growth in cultural hotspots, characteristic of the Neolithic transition worldwide. The unique extent of humanity's ability to modify its environment to markedly increase carrying capacity in South America is therefore an unexpectedly recent phenomenon.

  19. On the importance of cascading moisture recycling in South America

    Directory of Open Access Journals (Sweden)

    D. C. Zemp

    2014-06-01

    Full Text Available Continental moisture recycling is a crucial process of the South American climate system. Evapotranspiration from the Amazon river basin contributes to precipitation regionally and in the La Plata river basin. Here we present an in-depth analysis of South American moisture recycling. We quantify the importance of "cascading moisture recycling", which describes the exchange of moisture between the vegetation and the atmosphere through precipitation and re-evaporation cycles on its way between two locations on the continent. We use the Water Accounting Model 2-layers (WAM-2layers forced by precipitation from TRMM and evapotranspiration from MODIS for the period 2001 until 2010 to construct moisture recycling networks. These networks describe the direction and amount of moisture transported from its source (evapotranspiration to its destination (precipitation in South America. Model-based calculations of continental and regional recycling ratios in the Amazon basin compare well with other existing studies using different datasets and methodologies. Our results show that cascading moisture recycling contributes about 10% to the total precipitation over South America and 17% over the La Plata basin. Considering cascading moisture recycling increases the total dependency of the La Plata basin on moisture from the Amazon basin by about 25% from 23 to 29% during the wet season. Using tools from complex network analysis, we reveal the importance of the south-western part of the Amazon basin as a key intermediary region for continental moisture transport in South America during the wet season. Our results suggest that land use change in this region might have a stronger impact on downwind rainfed agriculture and ecosystem stability than previously thought.

  20. Geographic distribution of human Blastocystis subtypes in South America.

    Science.gov (United States)

    Ramírez, Juan David; Sánchez, Angie; Hernández, Carolina; Flórez, Carolina; Bernal, María Consuelo; Giraldo, Julio Cesar; Reyes, Patricia; López, Myriam Consuelo; García, Lineth; Cooper, Philip J; Vicuña, Yosselin; Mongi, Florencia; Casero, Rodolfo D

    2016-07-01

    Blastocystis is a cosmopolitan enteric protist colonizing probably more than 1 billion people. This protozoan exhibits genetic diversity and is subdivided into subtypes (STs). The aim of this study was to determine the distribution of Blastocystis STs in symptomatic and asymptomatic human samples from different countries of South America. A total of 346 fecal samples were genotyped by SSU rDNA showing ST1 (28.3%), ST2 (22.2%), ST3 (36.7%), ST4 (2%), ST5 (2.3%), ST6 (2%), ST7 (2.3%), ST8 (0.6%), ST12 (0.9%) and a novel ST (2.7%). These findings update the epidemiology of Blastocystis in South America and expand our knowledge of the phylogeographic differences exhibited by this stramenopile.

  1. Central and South America GPS geodesy - CASA Uno

    Science.gov (United States)

    Kellogg, James N.; Dixon, Timothy H.

    1990-01-01

    In January 1988, scientists from over 25 organizations in 13 countries and territories cooperated in the largest GPS campaign in the world to date. A total of 43 GPS receivers collected approximately 590 station-days of data in American Samoa, Australia, Canada, Colombia, Costa Rica, Ecuador, New Zealand, Norway, Panama, Sweden, United States, West Germany, and Venezuela. The experiment was entitled CASA Uno. Scientific goals of the project include measurements of strain in the northern Andes, subduction rates for the Cocos and Nazca plates beneath Central and South America, and relative motion between the Caribbean plate and South America. A second set of measurements are planned in 1991 and should provide preliminary estimates of crustal deformation and plate motion rates in the region.

  2. Poultry welfare scenario in South America: norms and regulations

    Directory of Open Access Journals (Sweden)

    RBTR Silva

    2011-06-01

    Full Text Available Animal welfare related issues have been intensely discussed in recent years as a consequence of changes in public attitudes and regulatory reforms that are taking place in many countries. A combination of public opinion pressure and trade policy has driven requirements for regulation and the World Trade Organization (WTO assigned the World Organization for Animal Health (OIE to develop guidelines that could be used as international standards. However, trade disputes related to animal welfare are not likely to be resolved under the auspices of OIE, and access to international markets may be questioned in a way that does not necessarily reflect attitudes to animal production in emerging economies, such as those in South America. This paper presents an overall view of basic welfare issues and points out specific items related to the present scenario of norms and regulations that are being implemented in South America, where the growing poultry industry is an important economic activity.

  3. Central and South America GPS geodesy - CASA Uno

    Science.gov (United States)

    Kellogg, James N.; Dixon, Timothy H.

    1990-01-01

    In January 1988, scientists from over 25 organizations in 13 countries and territories cooperated in the largest GPS campaign in the world to date. A total of 43 GPS receivers collected approximately 590 station-days of data in American Samoa, Australia, Canada, Colombia, Costa Rica, Ecuador, New Zealand, Norway, Panama, Sweden, United States, West Germany, and Venezuela. The experiment was entitled CASA Uno. Scientific goals of the project include measurements of strain in the northern Andes, subduction rates for the Cocos and Nazca plates beneath Central and South America, and relative motion between the Caribbean plate and South America. A second set of measurements are planned in 1991 and should provide preliminary estimates of crustal deformation and plate motion rates in the region.

  4. Postneoliberalism and Penality in South America: By Way of Introduction

    Directory of Open Access Journals (Sweden)

    Maximo Sozzo

    2017-03-01

    Full Text Available In the last two decades, there has been an extraordinary growth in incarceration rates in South America, with some variations across national contexts but generally in line with the same trend. Twenty years ago, incarceration rates were relatively low in most countries in the region; despite that knowledge, it has proved difficult to reconstruct the official data for that period. In 1992, with the exclusion of the small countries with less than one million inhabitants in the Northern region of South America such as Guyana, French Guyana and Surinam, only three countries had 100 prisoners or more per 100,000 inhabitants: Uruguay (100, Venezuela (133 and Chile (154 (see Figure 1. Several other national contexts reflected ‘'Scandinavian’' rates, such as Argentina (62, Peru (69, Ecuador (75 and Brazil (74. Download the PDF file to continue with this introduction to the articles in the dossier within this issue of the journal.

  5. Morphometrics of genus Caluromys (Didelphimorphia : Didelphidae) in northern South America

    OpenAIRE

    López Fuster, María José; Pérez Hernández, Roger; Ventura Queija, Jacinto

    2008-01-01

    We reviewed the morphometric relationships between different forms of the woolly opossum, genus Caluromys, in northern South America by means of univariate and multivariate analyses of skull characters. Results revealed that specimens from Trinidad and northern Venezuela differ substantially in size and shape from other representatives of the genus. Thus, we propose that they should be attributed to Caluromys trinitatis rather to C. philander. Consequently, the specific name given by Thomas (...

  6. Lowland tapir distribution and habitat loss in South America

    OpenAIRE

    2016-01-01

    The development of species distribution models (SDMs) can help conservation efforts by generating potential distributions and identifying areas of high environmental suitability for protection. Our study presents a distribution and habitat map for lowland tapir in South America. We also describe the potential habitat suitability of various geographical regions and habitat loss, inside and outside of protected areas network. Two different SDM approaches, MAXENT and ENFA, produced relative diff...

  7. The Determinants of Arms Spending in South America

    OpenAIRE

    2013-01-01

    In recent years, South America has witnessed a large increase in arms purchases. Nonetheless, there are important intraregional differences in terms of the allocation of resources for weapons acquisitions. How can we account for these disparities? Mainstream literature suggests that levels of arms importation depend on either the size of the defense budget or the perception of threat. In contrast, this article contends that the level of spending on arms is mainly determined by: (a) the expans...

  8. Ionospheric TEC Weather Map Over South America

    Science.gov (United States)

    Takahashi, H.; Wrasse, C. M.; Denardini, C. M.; Pádua, M. B.; de Paula, E. R.; Costa, S. M. A.; Otsuka, Y.; Shiokawa, K.; Monico, J. F. Galera; Ivo, A.; Sant'Anna, N.

    2016-11-01

    Ionospheric weather maps using the total electron content (TEC) monitored by ground-based Global Navigation Satellite Systems (GNSS) receivers over South American continent, TECMAP, have been operationally produced by Instituto Nacional de Pesquisas Espaciais's Space Weather Study and Monitoring Program (Estudo e Monitoramento Brasileiro de Clima Especial) since 2013. In order to cover the whole continent, four GNSS receiver networks, (Rede Brasileiro de Monitoramento Contínuo) RBMC/Brazilian Institute for Geography and Statistics, Low-latitude Ionospheric Sensor Network, International GNSS Service, and Red Argentina de Monitoreo Satelital Continuo, in total 140 sites, have been used. TECMAPs with a time resolution of 10 min are produced in 12 h time delay. Spatial resolution of the map is rather low, varying between 50 and 500 km depending on the density of the observation points. Large day-to-day variabilities of the equatorial ionization anomaly have been observed. Spatial gradient of TEC from the anomaly trough (total electron content unit, 1 TECU = 1016 el m-2 (TECU) 80) causes a large ionospheric range delay in the GNSS positioning system. Ionospheric plasma bubbles, their seeding and development, could be monitored. This plasma density (spatial and temporal) variability causes not only the GNSS-based positioning error but also radio wave scintillations. Monitoring of these phenomena by TEC mapping becomes an important issue for space weather concern for high-technology positioning system and telecommunication.

  9. Possible migration routes into South America deduced from mitochondrial DNA studies in Colombian Amerindian populations.

    Science.gov (United States)

    Keyeux, Genoveva; Rodas, Clemencia; Gelvez, Nancy; Carter, Dee

    2002-04-01

    Mitochondrial DNA haplotype studies have been useful in unraveling the origins of Native Americans. Such studies are based on restriction site and intergenic deletion/insertion polymorphisms, which define four main haplotype groups common to Asian and American populations. Several studies have characterized these lineages in North, Central, and South American Amerindian, as well as Na Dene and Aleutian populations. Siberian, Central Asian, and Southeast Asian populations have also been analyzed, in the hope of fully depicting the route(s) of migration between Asia and America. Colombia, a key route of migration between North and South America, has until now not been studied. To resolve the current lack of information about Colombian Amerindian populations, we have investigated the presence of the founder haplogroups in 25 different ethnic groups from all over the country. The present research is part of an interdisciplinary program, Expedición Humana, fostered by the Universidad Javeriana and Dr. J. E. Bernal V. The results show the presence of the four founder A-D Amerindian lineages, with varied distributions in the different populations, as well as the presence of other haplotypes in frequencies ranging from 3% to 26%. These include some unique or private polymorphisms, and also indicate the probable presence of other Asian and a few non-Amerindian lineages. A spatial structure is apparent for haplogroups A and D, and to a lesser extent for haplogroup C. While haplogroup A and D frequencies in Colombian populations from the northwestern side of the Andes resemble those seen in Central American Amerindians more than those seen in South American populations, their frequencies on the southeastern side more closely resemble the bulk of South American frequencies so far reported, raising the question as to whether they reflect more than one migration route into South America. High frequencies of the B lineage are also characteristic of some populations. Our

  10. Petroleum geology of Pacific margin of Central America and northern South America, from Guatemala to Ecuador

    Energy Technology Data Exchange (ETDEWEB)

    Scrutton, M.E.; Escalante, G.F.

    1986-07-01

    Exploration for hydrocarbons along the Pacific margin of Central America and northern South America has been limited and spasmodic. Less than 100 exploration wells have been drilled, with nearly 50 of these being in the Santa Elena, Progreso, and Guayas basins in Ecuador. Shows have been reported in some wells, and a few oil seeps are known. The only commercial production established to date has been from the Santa Elena Peninsula in Ecuador in the extreme south of the study area. Understanding of the geology in this part of the continental margin is incomplete at best. This paper reviews present-day knowledge in an attempt to define the sedimentary basins better, to characterize their structure and stratigraphy, and to assess their petroleum prospects. The area of continental margin reviewed is to the north, located northwest of the trench system where oceanic crust of the Cocos plate subducts under the Caribbean plate, and to the south, where the northern part of the Nazca plate collides with the South American plate. This plate tectonic setting forms the framework on which local structural and sedimentary events have created a series of relatively small trench-slope and forearc basins in what is now the coastal plain and adjacent offshore area of Central and South America, south or west of a line of mountain ranges with active volcanism. Sedimentary fill is generally of Tertiary age. The basins and subbasins recognized and described include: in Ecuador - Guayas, Santa Elena, Progreso, Valdivia, Bajo Grande, Manta, Muisne-Esmeraldas, and Borbon; in Colombia - Choco-Pacific; in Panama - Gulf of Panama basin complex (Santiago, Tonosi, Sambu), and Burica-Chiriqui; in Costa Rica - Terraba and Coronado/Tempisque; in Nicaragua - San Juan del Sur; and in the Honduras, El Salvador, and Guatemala - the Pacific coastal basin.

  11. Deep convective events influence ozone variability in southeast South America

    Science.gov (United States)

    Gamelin, B.; Carvalho, L. V.

    2016-12-01

    When tropospheric greenhouse gasses are deposited in the stratosphere (especially water vapor) the system chemically responds with incoming solar radiation to destroy ozone. As a result, these processes have a cooling effect on the stratosphere, and a warming effect in the troposphere. Areas in South America influenced by the South Atlantic Convergent Zone, the Chaco Low, and South American Low Level Jet are associated with large mesoscale convective systems (MCS) and are experiencing decreased ozone levels above 150 mb. Utilizing Aqua's Atmospheric Infrared Sounder (AIRS) V6 level 3 data from 2002 to 2016, deep convective events are identified in Southeast South America between 22°S - 36°S (Southern Brazil, Uruguay, Southern Paraguay and Northeast Argentina) and analyzed as a contributor to changes in the upper tropopause-lower stratosphere (UTLS) ozone during the austral spring. These events are established to identify the transport of tropospheric greenhouse gasses to the lower stratosphere (especially water vapor and methane) related to ozone loss between 150 - 10 mb due to direct injection above the cold point tropopause, determine UTLS temperature variations, and classify lower stratospheric hydration.

  12. Perspectivs and challenges of phenology research on South America

    Science.gov (United States)

    Patrícia Morellato, Leonor

    2017-04-01

    Detecting plant responses to environmental changes across the Southern Hemisphere is an important question in the global agenda, as there is still a shortage of studies addressing phenological trends related to global warming. Here I bring a fresh perspective on the current knowledge of South America's phenology, and discusss the challenges and future research agendas for one of the most diverse regions of the world. I will syntethize: (i) What is the current focus of contemporany phenological research in South America? (ii) Is phenology contributing to the detection of trends and shifts related to climate or antropogenic changes? (iii) How has phenology been integrated to conservation, restoration, and management of natural vegetation and endangered species? (iv) What would be the main challenges and new avenues for South American phenological research in the 21st century? (v) Can we move towards phenology monitoring networks, linked to citizen science and education? My perspective is based on recent reviews addressing the Southeastern Hemisphere, South America, and Neotropical phenology; and on reviews and essays on the contribution of phenological research to biodiversity conservation, management, and ecological restoration, emphasizing tropical, species-rich ecosystems. Phenological research has grown at an unprecedented rate in the last 20 years, surpassing 100 articles per year after 2010. There is still a predominance of short-term studies (2-3 years) describing patterns and drivers for reproduction and leaf exchange. Only 10 long-term studies were found, based on direct observations or plant traps, and this number did not add much to the previous surveys. Therefore, we remain in need of more long-term studies to enhance the contribution of phenology to climate change research in South America. It is also mandatory to bring conservation issues to phenology research. The effects of climatic and antropogenic changes on plant phenology have been addressed

  13. Biennial relationship of rainfall variability between Central America and equatorial South America

    Science.gov (United States)

    Wu, Renguang; Zhang, Li

    2010-04-01

    Observations indicate that equatorial South American rainfall anomalies in boreal winter are preceded by the same sign Central American rainfall anomalies in boreal summer and tend to be succeeded by opposite sign Central American rainfall anomalies in the following summer. The in-phase relationship from summer to winter rainfall is attributed to direct effects of El Niño-Southern Oscillation (ENSO). Anomalous convection associated with warm ENSO events induces anomalous descent and suppresses precipitation along the convection region that migrates southeastward from Central America in boreal summer to tropical South America in boreal winter. The out-of-phase relationship from winter to summer rainfall is related to tropical North Atlantic sea surface temperature (SST) anomalies induced by wind-evaporation and cloud-radiation changes in response to ENSO-generated anomalous convection over tropical South America. In years when ENSO switches its phase from winter to summer, the direct effects of ENSO can also lead to the out-of-phase relationship.

  14. Checklist of Helminth parasites of Amphibians from South America.

    Science.gov (United States)

    Campião, Karla Magalhães; Morais, Drausio Honorio; Dias, Olívia Tavares; Aguiar, Aline; Toledo, Gislayne De Melo; Tavares, Luiz Eduardo Roland; Da Silva, Reinaldo José

    2014-07-30

    Parasitological studies on helminths of amphibians in South America have increased in the past few years. Here, we present a list with summarized data published on helminths of South American amphibians from 1925 to 2012, including a list of helminth parasites, host species, and geographic records. We found 194 reports of helminths parasitizing 185 amphibian species from eleven countries: Argentina, Brazil, Chile, Colombia, Equador, French Guyana, Guyana, Paraguay, Peru, Uruguay and Venezuela. Helminth biodiversity includes 278 parasite species of the groups Acanthocephala, Nematoda, Cestoda, Monogenea and Trematoda. A list of helminth parasite species per host, and references are also presented. This contribution aims to document the biodiversity of helminth parasites in South American amphibians, as well as identify gaps in our knowledge, which in turn may guide subsequent studies. 

  15. Response of internal solitary waves to tropical storm Washi in the northwestern South China Sea

    Directory of Open Access Journals (Sweden)

    Z. H. Xu

    2011-11-01

    Full Text Available Based on in-situ time series data from an array of temperature sensors and an acoustic Doppler current profiler on the continental shelf of the northwestern South China Sea, a sequence of internal solitary waves (ISWs were observed during the passage of tropical storm Washi in the summer of 2005, which provided a unique opportunity to investigate the ISW response to the tropical cyclone. The passing tropical storm is found to play an important role in affecting the stratification structure of the water column, and consequently leading to significant variability in the propagating features of the ISWs, such as the polarity reversal and amplitude variations of the waves. The response of the ISWs to Washi can be divided into two stages, direct forcing by the strong wind (during the arrival of Washi and remote forcing via the near-inertial internal waves induced by the tropical storm (after the passage of Washi. The field observations as well as a theoretical analysis suggest that the variations of the ISWs closely coincide with the changing stratification structure and shear currents in accompanied by the typhoon wind and near-inertial waves. This study presents the first observations and analysis of the ISW response to the tropical cyclone in the South China Sea.

  16. Environmental law in the regional integration of South America

    Directory of Open Access Journals (Sweden)

    Gisele Lorena González Celis

    2013-10-01

    Full Text Available Environmental law has two main features: the regulation and control of the activities of raw material extraction and conservation of endemic ecosystems and special care. The harmonization of national environmental rights becomes an urgent task in the context of regional integration processes experienced by South America, as the ecosystems in the territory are of great importance and are vulnerable according to the type of development that poses. Currently, the Environmental Law is a subject that has not been intensively discussed between countries, but at international summits, countries have established this subject as a focus of global concern. Therefore, it is essential that this issue is placed on the political agenda to define what are the environmental guidelines in the context of regional integration in South America. This document provides the reader an approach to some of the challenges and difficulties faced by countries, when dealing in the South American political agenda, the issue of harmonization of environmental regulatory frameworks.

  17. Ocean Global Warming Impacts on the South America Climate

    Science.gov (United States)

    Ramos-Da-Silva, Renato

    2016-03-01

    The global Ocean-Land-Atmosphere Model (OLAM) model was used to estimate the impacts of the global oceanic warming on the climate projections for the 21st Century focusing on the South America region. This new model is able to represent simultaneously the global and regional scales using a refining grid approach for the region of interest. First, the model was run for a 31-year control period consisting on the years 1960-1990 using the monthly Sea Surface Temperature (SST) from the Atmospheric Model Intercomparison Project (AMIP) data as a driver for the ocean fluxes. Then, the model was run for the period 2010-2100 using the monthly projected SST from the Hadley Center model (HadCM3) as a driver for the oceanic changes. The model was set up with an icosahedral triangular global grid having about 250 km of grid spacing and with a refining grid resolution with the cells reaching about 32 km over the South America region. The results show an overall temperature increase mainly over the center of the Amazon basin caused by the increase of the greenhouse effect of the water vapor; a decrease on precipitation mainly over the northeast Brazil and an increase in the south and over the western Amazon region; and a major increase on the near surface wind speed. These results are similar to the global coupled models; however, OLAM has a novel type of grid that can provide the interaction between the global and regional scales simultaneously.

  18. Ocean Global Warming Impacts on the South America Climate

    Directory of Open Access Journals (Sweden)

    Renato eRamos-Da-Silva

    2016-03-01

    Full Text Available The global Ocean-Land-Atmosphere Model (OLAM model was used to estimate the impacts of the global oceanic warming on the climate projections for the 21st Century focusing on the South America region. This new model is able to represent simultaneously the global and regional scales using a refining grid approach for the region of interest. First, the model was run for a 31-year control period consisting on the years 1960-1990 using the monthly Sea Surface Temperature (SST from the Atmospheric Model Intercomparison Project (AMIP data as a driver for the ocean fluxes. Then, the model was run for the period 2010-2100 using the monthly projected SST from the Hadley Center model (HadCM3 as a driver for the oceanic changes. The model was set up with an icosahedral triangular global grid having about 250 km of grid spacing and with a refining grid resolution with the cells reaching about 32 km over the South America region. The results show an overall temperature increase mainly over the center of the Amazon basin caused by the increase of the greenhouse effect of the water vapor; a decrease on precipitation mainly over the northeast Brazil and an increase in the south and over the western Amazon region; and a major increase on the near surface wind speed. These results are similar to the global coupled models; however, OLAM has a novel type of grid that can provide the interaction between the global and regional scales simultaneously.

  19. Transboundary water resources governance: institutional fragilities in South America

    Directory of Open Access Journals (Sweden)

    Fernanda MELLO SANT’ANNA

    2015-04-01

    Full Text Available Since the 1990s, the concept of governance rose to prominence in the literature regarding transboundary waters, as well as the international cooperation among riparian States. This article seeks to determine the fragilities in the governance of the major transboundary water resources in South America: the Amazon and La Plata River Basins. In spite of the current international agreements, including those regarding infrastructure development and supranational organizations, water governance presents fragilities related to institutional problems, lack of social participation and dif?culties in structuring a common project of development.

  20. Regional Climate Modeling over South America: A Review

    Directory of Open Access Journals (Sweden)

    Silvina A. Solman

    2013-01-01

    Full Text Available This review summarizes the progress achieved on regional climate modeling activities over South America since the early efforts at the beginning of the 2000s until now. During the last 10 years, simulations with regional climate models (RCMs have been performed for several purposes over the region. Early efforts were mainly focused on sensitivity studies to both physical mechanisms and technical aspects of RCMs. The last developments were focused mainly on providing high-resolution information on regional climate change. This paper describes the most outstanding contributions from the isolated efforts to the ongoing coordinated RCM activities in the framework of the CORDEX initiative, which represents a major endeavor to produce ensemble climate change projections at regional scales and allows exploring the associated range of uncertainties. The remaining challenges in modeling South American climate features are also discussed.

  1. A GPS estimate of relative motion between North and South America

    Science.gov (United States)

    Dixon, Timothy H.; Mao, Ailin

    GPS velocity data are used to estimate the Euler vector describing rigid body motion of North America relative to South America. Assuming the boundary between the North and South American plates is located near the Fifteen Twenty fracture zone in the equatorial Atlantic, the Euler vector predicts extension across the Royal Trough up to 1 mm/yr, and convergence across the Barracuda Ridge at about 2 mm/yr, in agreement with geological estimates averaged over tens of millions of years. Further west, convergence between North and South America at rates up to 8 mm/yr may contribute to deformation of the Caribbean plate along its southwest boundary with South America.

  2. Bluetongue disease and seroprevalence in South American camelids from the northwestern region of the United States.

    Science.gov (United States)

    Allen, Andrew J; Stanton, James B; Evermann, James F; Fry, Lindsay M; Ackerman, Melissa G; Barrington, George M

    2015-03-01

    In late summer/early fall of 2013, 2 South American camelids from central Washington were diagnosed with fatal bluetongue viral disease, an event which is rarely reported. A 9-year-old intact male llama (Lama glama), with a 1-day history of anorexia, recumbency, and dyspnea before death. Abundant foam discharged from the mouth and nostrils, and the lungs were severely edematous on postmortem examination. Histologically, there was abundant intra-alveolar edema with fibrin. Hemorrhage and edema disrupted several other organs. Bluetongue viral RNA was detected by reverse transcription polymerase chain reaction (RT-PCR), and serotype 11 was identified by sequencing a segment of the VP2 outer capsid gene. Approximately 1 month later, at a site 150 miles north of the index case, a 2-year-old female alpaca with similar, acutely progressive clinical signs was reported. A postmortem examination was performed, and histologic lesions from the alpaca were similar to those of the llama, and again serotype 11 was detected by PCR. The occurrence of bluetongue viral infection and disease is described in the context of seasonal Bluetongue virus activity within the northwestern United States and southwestern Canada.

  3. Integrating mechanistic and empirical model projections to assess climate impacts on tree species distributions in northwestern North America.

    Science.gov (United States)

    Case, Michael J; Lawler, Joshua J

    2017-05-01

    Empirical and mechanistic models have both been used to assess the potential impacts of climate change on species distributions, and each modeling approach has its strengths and weaknesses. Here, we demonstrate an approach to projecting climate-driven changes in species distributions that draws on both empirical and mechanistic models. We combined projections from a dynamic global vegetation model (DGVM) that simulates the distributions of biomes based on basic plant functional types with projections from empirical climatic niche models for six tree species in northwestern North America. These integrated model outputs incorporate important biological processes, such as competition, physiological responses of plants to changes in atmospheric CO2 concentrations, and fire, as well as what are likely to be species-specific climatic constraints. We compared the integrated projections to projections from the empirical climatic niche models alone. Overall, our integrated model outputs projected a greater climate-driven loss of potentially suitable environmental space than did the empirical climatic niche model outputs alone for the majority of modeled species. Our results also show that refining species distributions with DGVM outputs had large effects on the geographic locations of suitable habitat. We demonstrate one approach to integrating the outputs of mechanistic and empirical niche models to produce bioclimatic projections. But perhaps more importantly, our study reveals the potential for empirical climatic niche models to over-predict suitable environmental space under future climatic conditions. © 2016 John Wiley & Sons Ltd.

  4. Clinical epidemiology of acute hepatitis C in South America.

    Science.gov (United States)

    Dirchwolf, Melisa; Marciano, Sebastián; Mauro, Ezequiel; Ruf, Andrés Eduardo; Rezzonico, Lucrecia; Anders, Margarita; Chiodi, Daniela; Petta, Néstor Gill; Borzi, Silvia; Tanno, Federico; Ridruejo, Ezequiel; Barreyro, Fernando; Shulman, Carolina; Plaza, Pablo; Carbonetti, Rodolfo; Tadey, Luciana; Schroder, Teresa; Fainboim, Hugo

    2017-02-01

    There is scarce data pertaining to acute hepatitis C (aHC) infection in South America. We aimed to describe clinical characteristics and evolution of aHC in a South American cohort. A retrospective survey was conducted at 13 hepatology units. All patients ≥16 years old with aHC diagnosis were included. Demographic, clinical and outcome information were registered in a standardized ad hoc questionnaire. Sixty-four patients were included. The majority were middle-aged (median age: 46 years) and female (65.6%); most of them were symptomatic at diagnosis (79.6%). HCV-1 was the most prevalent genotype (69.2%). Five patients had liver failure: three cases of severe acute hepatitis, one case of fulminant hepatitis and one case of acute-on-chronic liver failure. Nosocomial exposure was the most prevalent risk factor. Evolution was assessed in 46 patients. In the untreated cohort, spontaneous resolution occurred in 45.8% and was associated with higher values of AST/ALT and with the absence of intermittent HCV RNA viremia (P = 0.01, 0.05, and 0.01, respectively). In the treated cohort, sustained virological response was associated with nosocomial transmission and early treatment initiation (P = 0.04 each). The prevalence of nosocomial transmission in this South-American cohort of aHC stresses the importance of following universal precautions to prevent HCV infection. J. Med. Virol. 89:276-283, 2017. © 2016 Wiley Periodicals, Inc.

  5. Economic aspects for South America energy integration; Aspectos economicos para a integracao energetica da America do Sul

    Energy Technology Data Exchange (ETDEWEB)

    Vela, Jorge Alberto Alcala; Cardozo, Fernando Simoes [ELETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Expansion of the internal market and external, production on a large scale and more dynamic economic growth would be the consequences of a regional integration in South America. However, due to the specific characteristics of South America this process did not occur. Many attempts were made through the years with the creation of institutions that tried to promote the integration of different forms of South America. This article analyses the current economic conditions in which this initiative is to achieve an energy integration, which seems feasible given the provision expresses the presidents of South American countries before a possible rationing of energy. Through analysis of the results it may be concluded that there is a growing demand for energy in all countries, which should be resolved first in order not to cut the development of South America. The main economic aspects which affect the process of integrating energy are the commercial structures of energy, the energy complementarities, the degree of development of infrastructure for interconnection, the industrial structure and conformation electric business. However, an immediate solution would be to boost bilateral integration energy projects and construction of transmission lines that interconnect the regional stations for the supply of electric energy. Moreover, as the conditions are not improved political and economic and there is no compatible models between technical institutions and legal and administrative, will not be achieved significant progress in the process of regional energy integration of South America. (author)

  6. Annotated checklist of fish cestodes from South America

    Science.gov (United States)

    Alves, Philippe V.; de Chambrier, Alain; Scholz, Tomáš; Luque, José L.

    2017-01-01

    Abstract An exhaustive literature search supplemented by a critical examination of records made it possible to present an annotated checklist of tapeworms (Cestoda) that, as adults or larvae (metacestodes), parasitize freshwater, brackish water and marine fishes, i.e. cartilaginous and bony fishes, in South America. The current knowledge of their species diversity, host associations and geographical distribution is reviewed. Taxonomic problems are discussed based on a critical evaluation of the literature and information on DNA sequences of individual taxa is provided to facilitate future taxonomic and phylogenetic studies. As expected, the current knowledge is quite uneven regarding the number of taxa and host-associations reported from the principal river basins and marine ecoregions. These differences may not only reflect the actual cestode richness but may also be due to the research effort that has been devoted to unravelling the diversity of these endoparasitic helminths in individual countries. A total of 297 valid species, 61 taxa identified to the generic level, in addition to unidentified cestodes, were recorded from 401 species of fish hosts. Among the recognized cestode orders, 13 have been recorded in South America, with the Onchoproteocephalidea displaying the highest species richness, representing c. 50% of all species diversity. The majority of records include teleost fish hosts (79%) that harbour larval and adult stages of cestodes, whereas stingrays (Myliobatiformes) exhibit the highest proportion of records (39%) among the elasmobranch hosts. Fish cestodes are ubiquitous in South America, being mostly recorded from the Warm Temperate Southeastern Pacific (WTSP; 31%) for marine hosts and the Amazon River basin (45%) for freshwater ones. The following problems were detected during the compilation of literary data: (i) unreliability of many records; (ii) poor taxonomic resolution, i.e. identification made only to the genus or even family level; (iii

  7. Annotated checklist of fish cestodes from South America

    Directory of Open Access Journals (Sweden)

    Philippe V. Alves

    2017-02-01

    Full Text Available An exhaustive literature search supplemented by a critical examination of records made it possible to present an annotated checklist of tapeworms (Cestoda that, as adults or larvae (metacestodes, parasitize freshwater, brackish water and marine fishes, i.e. cartilaginous and bony fishes, in South America. The current knowledge of their species diversity, host associations and geographical distribution is reviewed. Taxonomic problems are discussed based on a critical evaluation of the literature and information on DNA sequences of individual taxa is provided to facilitate future taxonomic and phylogenetic studies. As expected, the current knowledge is quite uneven regarding the number of taxa and host-associations reported from the principal river basins and marine ecoregions. These differences may not only reflect the actual cestode richness but may also be due to the research effort that has been devoted to unravelling the diversity of these endoparasitic helminths in individual countries. A total of 297 valid species, 61 taxa identified to the generic level, in addition to unidentified cestodes, were recorded from 401 species of fish hosts. Among the recognized cestode orders, 13 have been recorded in South America, with the Onchoproteocephalidea displaying the highest species richness, representing c. 50% of all species diversity. The majority of records include teleost fish hosts (79% that harbour larval and adult stages of cestodes, whereas stingrays (Myliobatiformes exhibit the highest proportion of records (39% among the elasmobranch hosts. Fish cestodes are ubiquitous in South America, being mostly recorded from the Warm Temperate Southeastern Pacific (WTSP; 31% for marine hosts and the Amazon River basin (45% for freshwater ones. The following problems were detected during the compilation of literary data: (i unreliability of many records; (ii poor taxonomic resolution, i.e. identification made only to the genus or even family level

  8. Leioproctus rosellae sp. n., the first record of the genus from northern South America (Hymenoptera, Colletidae

    Directory of Open Access Journals (Sweden)

    Victor Gonzalez

    2011-10-01

    Full Text Available Leioproctus Smith is a diverse colletine genus found in the Australian region and primarily temperate areas of South America. A new species of Leioproctus subgenus Perditomorpha Ashmead, L. rosellae Gonzalez sp. n., from a tropical dry forest of the Caribbean coast of Colombia is described and figured. This is the first record of the genus from northern South America.

  9. Leioproctus rosellae sp. n., the first record of the genus from northern South America (Hymenoptera, Colletidae)

    Science.gov (United States)

    Gonzalez, Victor H.; Florez, Jaime

    2011-01-01

    Abstract Leioproctus Smith is a diverse colletine genus found in the Australian region and primarily temperate areas of South America. A new species of Leioproctus subgenus Perditomorpha Ashmead, Leioproctus rosellae Gonzalez, sp. n., from a tropical dry forest of the Caribbean coast of Colombia is described and figured. This is the first record of the genus from northern South America. PMID:22287881

  10. Imaging Transition Zone Thickness Beneath South America from SS Precursors

    Science.gov (United States)

    Schmerr, N.; Garnero, E.

    2006-12-01

    We image detailed upper mantle discontinuity structure beneath a number of geologically active regions, including the South American subduction zone, the Scotia plate subduction zone, and several volcanic hotspots (e.g., the Galapagos Islands), in a region ~10,000 km by 10,000 km wide, spanning 70° S to 20° N and 20° W to 110° W. Precursors to the seismic phase SS are analyzed, which form as a result of underside reflections off seismic discontinuities beneath the midpoint of the SS path and are highly sensitive to discontinuity depth and sharpness. Our SS dataset consists of over 15,000 high-quality transverse component broadband displacement seismograms collected from the Incorporated Research Institutions for Seismology (IRIS), the Canadian National Seismic Network (CNSN), as well as data from EarthScope seismic stations, and from the Canadian Northwest Experiment (CANOE) temporary broadband array deployment. This dataset densely samples several regions in our study area and significantly improves the sampling for this area compared to previous precursor studies. Data with common central SS bouncepoints are stacked to enhance precursory phases. Solution discontinuity structure depends on a number of factors, including dominant seismic period, crustal correction, signal-to-noise ratio threshold, and tomography model used for mantle heterogeneity correction. We exclude precursor data predicted to interfere with other seismic phases, such as topside reflections (e.g., s670sS), which have been demonstrated to contaminate final stacks. Solution transition zone thickness is at least 20 km thicker than global average estimates of 242 km along the northwestern portion of the South American subduction complex (Peru, Ecuador, and Columbia); this thickening extends 1000-1500 km to the east beneath the continent, but does not appear to continue south of -20° latitude along the convergent margin. A minimum of 10 km of thickening is imaged to the west of the Scotia

  11. No Red River capture since the late Oligocene: Geochemical evidence from the Northwestern South China Sea

    Science.gov (United States)

    Zhao, Meng; Shao, Lei; Liang, Jianshe; Li, Qianyu

    2015-12-01

    Rare earth elements (REE) in the sediment samples of six industrial wells from the Yinggehai-Song Hong Basin in the Northwestern South China Sea were analyzed and compared with the detrital zircon U-Pb data from earlier studies to extrapolate sediment provenance. The results reveal that the Red River (Song Hong River), Hainan Island and Central Vietnam have been the main provenances of the Yinggehai-Song Hong Basin since the late Oligocene. The Red River has been supplying sediments with positive Eu anomalies from basic-ultrabasic metamorphic and volcanic parent rocks to most parts of the basin, while Hainan Island has delivered sediments with negative Eu anomalies from granitic and sedimentary parent rocks to the eastern slope area of the basin. The progradational downlap structures in the seismic profiles also support the finding that the sediment supply is mainly from the Red River and from Hainan Island. The metamorphic rocks, which are widespread within the Red River drainage, not only provided high volumes of sediments to the basin but also contributed to the positive Eu anomalies observed. Because their REE and U-Pb signatures are similar to those of the Red River source, the metamorphic and igneous rocks of the Song Ma Suture Zone, Kontum Massif, and Jinghong area were probably parts of a large basic provenance region before being separated by strike-slip movements along the Ailao Shan-Red River shear zone. Furthermore, our results indicate that the Red River drainage area has been relatively stable since the late Oligocene. Therefore, if a drainage capture from the Red River occurred, it is likely to have taken place before the late Oligocene.

  12. Applying complex networks to evaluate precipitation patterns over South America

    Science.gov (United States)

    Ciemer, Catrin; Boers, Niklas; Barbosa, Henrique; Kurths, Jürgen; Rammig, Anja

    2016-04-01

    The climate of South America exhibits pronounced differences between the wet- and the dry-season, which are accompanied by specific synoptic events like changes in the location of the South American Low Level Jet (SALLJ) and the establishment of the South American Convergence Zone (SACZ). The onset of these events can be related to the presence of typical large-scale precipitation patterns over South America, as previous studies have shown[1,2]. The application of complex network methods to precipitation data recently received increased scientific attention for the special case of extreme events, as it is possible with such methods to analyze the spatiotemporal correlation structure as well as possible teleconnections of these events[3,4]. In these approaches the correlation between precipitation datasets is calculated by means of Event Synchronization which restricts their applicability to extreme precipitation events. In this work, we propose a method which is able to consider not only extreme precipitation but complete time series. A direct application of standard similarity measures in order to correlate precipitation time series is impossible due to their intricate statistical properties as the large amount of zeros. Therefore, we introduced and evaluated a suitable modification of Pearson's correlation coefficient to construct spatial correlation networks of precipitation. By analyzing the characteristics of spatial correlation networks constructed on the basis of this new measure, we are able to determine coherent areas of similar precipitation patterns, spot teleconnections of correlated areas, and detect central regions for precipitation correlation. By analyzing the change of the network over the year[5], we are also able to determine local and global changes in precipitation correlation patterns. Additionally, global network characteristics as the network connectivity yield indications for beginning and end of wet- and dry season. In order to identify

  13. Crash and rebound of indigenous populations in lowland South America

    Science.gov (United States)

    Hamilton, Marcus J.; Walker, Robert S.; Kesler, Dylan C.

    2014-04-01

    Lowland South America has long been a battle-ground between European colonization and indigenous survival. Initial waves of European colonization brought disease epidemics, slavery, and violence that had catastrophic impacts on indigenous cultures. In this paper we focus on the demography of 238 surviving populations in Brazil. We use longitudinal censuses from all known indigenous Brazilian societies to quantify three demographic metrics: 1) effects of European contact on indigenous populations; 2) empirical estimates of minimum viable population sizes; and 3) estimates of post-contact population growth rates. We use this information to conduct population viability analysis (PVA). Our results show that all surviving populations suffered extensive mortality during, and shortly after, contact. However, most surviving populations exhibit positive growth rates within the first decade post-contact. Our findings paint a positive demographic outlook for these indigenous populations, though long-term survival remains subject to powerful externalities, including politics, economics, and the pervasive illegal exploitation of indigenous lands.

  14. OXA-type carbapenemases in Acinetobacter baumannii in South America.

    Science.gov (United States)

    Opazo, Andrés; Domínguez, Mariana; Bello, Helia; Amyes, Sebastian G B; González-Rocha, Gerardo

    2012-04-13

    Acinetobacter baumannii is an opportunistic pathogen that is frequently involved in outbreaks of infection, occurring mostly in intensive care units. The increasing incidence of carbapenem resistance in A. baumannii worldwide is a concern since it limits drastically the range of therapeutic alternatives. The most important mechanism of carbapenem resistance is the enzymatic hydrolysis mediated by carbapenemases. In A. baumannii these enzymes are usually OXA-type carbapenemases, and belong to class D according to the classification of Ambler. The OXA-type carbapenemases are divided into five subgroups, four of which correspond to acquired carbapenemases, which accounts for the distribution of genes blaOXA in different geographic areas. In this work we review the different types of OXA-type carbapenemases present in A. baumannii, emphasizing the current situation in South America with special mention to the findings in Chile.

  15. How different proxies record precipitation variability over southeastern South America

    Energy Technology Data Exchange (ETDEWEB)

    Chiessi, Cristiano M; Mulitza, Stefan; Paetzold, Juergen; Wefer, Gerold, E-mail: chiessi@uni-bremen.d [MARUM-Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, 28359 Bremen (Germany)

    2010-03-15

    Detrending natural and anthropogenic components of climate variability is arguably an issue of utmost importance to society. To accomplish this issue, one must rely on a comprehensive understanding of the natural variability of the climate system on a regional level. Here we explore how different proxies (e.g., stalagmite oxygen isotopic composition, pollen percentages, bulk sediment elemental ratios) record Holocene precipitation variability over southeastern South America. We found a general good agreement between the different records both on orbital and centennial time-scales. Dry mid Holocene, and wet late Holocene, Younger Dryas and a period between {approx}9.4 and 8.12 cal kyr BP seem to be pervasive features. Moreover, we show that proxy-specific sensitivity can greatly improve past precipitation reconstructions.

  16. Fossorial snake genus Apostolepis from South America (Serpentes: Colubridae: Elapomorphinae

    Directory of Open Access Journals (Sweden)

    De Lema, Thales

    2001-07-01

    Full Text Available An update commented list of the snake genus Apostolepis from South America, with keys for identification of the species. They are fossorial snakes that present different coloration according their distribution: (a 7 to 3 dark stripes coloration, without light nuchal collar (if present, vestigial, with snout not projected beyond jaws - in Amazonian and enclaves within Caatinga domain; (b 5 dark striped dorsal pattern, snout projected, usually without white nuchal collars — from region of contact between Cerrado and Chaco domains; (c dorsal pattern coloration uniformly red, with nucho-cervical collars, snout usually projected — in Cerrado with dispersion to Chaco and Caatinga; (d 2 or none dark stripes dorsally, venter immaculate or with black blotches, snout projecting: (e an aberrant pattern with oblique black dorsal stripes, without collars, head black and snout projecting — one species in an enclave within Caatinga, with 17 rows of scales instead of 15.

  17. Forest biomass density across large climate gradients in northern South America is related to water availability but not with temperature

    Science.gov (United States)

    Cayuela, Luis; González-Caro, Sebastián; Aldana, Ana M.; Stevenson, Pablo R.; Phillips, Oliver; Cogollo, Álvaro; Peñuela, Maria C.; von Hildebrand, Patricio; Jiménez, Eliana; Melo, Omar; Londoño-Vega, Ana Catalina; Mendoza, Irina; Velásquez, Oswaldo; Fernández, Fernando; Serna, Marcela; Velázquez-Rua, Cesar; Benítez, Doris; Rey-Benayas, José M.

    2017-01-01

    Understanding and predicting the likely response of ecosystems to climate change are crucial challenges for ecology and for conservation biology. Nowhere is this challenge greater than in the tropics as these forests store more than half the total atmospheric carbon stock in their biomass. Biomass is determined by the balance between biomass inputs (i.e., growth) and outputs (mortality). We can expect therefore that conditions that favor high growth rates, such as abundant water supply, warmth, and nutrient-rich soils will tend to correlate with high biomass stocks. Our main objective is to describe the patterns of above ground biomass (AGB) stocks across major tropical forests across climatic gradients in Northwestern South America. We gathered data from 200 plots across the region, at elevations ranging between 0 to 3400 m. We estimated AGB based on allometric equations and values for stem density, basal area, and wood density weighted by basal area at the plot-level. We used two groups of climatic variables, namely mean annual temperature and actual evapotranspiration as surrogates of environmental energy, and annual precipitation, precipitation seasonality, and water availability as surrogates of water availability. We found that AGB is more closely related to water availability variables than to energy variables. In northwest South America, water availability influences carbon stocks principally by determining stand structure, i.e. basal area. When water deficits increase in tropical forests we can expect negative impact on biomass and hence carbon storage. PMID:28301482

  18. Forest biomass density across large climate gradients in northern South America is related to water availability but not with temperature.

    Science.gov (United States)

    Álvarez-Dávila, Esteban; Cayuela, Luis; González-Caro, Sebastián; Aldana, Ana M; Stevenson, Pablo R; Phillips, Oliver; Cogollo, Álvaro; Peñuela, Maria C; von Hildebrand, Patricio; Jiménez, Eliana; Melo, Omar; Londoño-Vega, Ana Catalina; Mendoza, Irina; Velásquez, Oswaldo; Fernández, Fernando; Serna, Marcela; Velázquez-Rua, Cesar; Benítez, Doris; Rey-Benayas, José M

    2017-01-01

    Understanding and predicting the likely response of ecosystems to climate change are crucial challenges for ecology and for conservation biology. Nowhere is this challenge greater than in the tropics as these forests store more than half the total atmospheric carbon stock in their biomass. Biomass is determined by the balance between biomass inputs (i.e., growth) and outputs (mortality). We can expect therefore that conditions that favor high growth rates, such as abundant water supply, warmth, and nutrient-rich soils will tend to correlate with high biomass stocks. Our main objective is to describe the patterns of above ground biomass (AGB) stocks across major tropical forests across climatic gradients in Northwestern South America. We gathered data from 200 plots across the region, at elevations ranging between 0 to 3400 m. We estimated AGB based on allometric equations and values for stem density, basal area, and wood density weighted by basal area at the plot-level. We used two groups of climatic variables, namely mean annual temperature and actual evapotranspiration as surrogates of environmental energy, and annual precipitation, precipitation seasonality, and water availability as surrogates of water availability. We found that AGB is more closely related to water availability variables than to energy variables. In northwest South America, water availability influences carbon stocks principally by determining stand structure, i.e. basal area. When water deficits increase in tropical forests we can expect negative impact on biomass and hence carbon storage.

  19. Bovine spongiform encephalopathy in South America: a regional preventive approach.

    Science.gov (United States)

    van Gelderen, C; Gimeno, E J; Schudel, A A

    2003-04-01

    Bovine spongiform encephalopathy (BSE) is a neurodegenerative disease of cattle caused by prions that was first described in the United Kingdom (UK) in 1986. The BSE epizootic that commenced in the UK in the 1980s has since spread into other countries in Europe and Asia through exports of contaminated meat-and-bone meal or infected cattle. Over the past few years, other emerging or reemerging diseases have spread into previously free countries or regions through international trade. This negative effect of globalisation means that to implement successful preventive and strategic programmes to safeguard animal health, such programmes must, as a priority, take a regional approach. Global thinking, regional planning and local performance constitute the key factors for the successful control of animal diseases. In South America, initial preventive actions against BSE were adopted in 1989. Further measures adopted since then and based on new scientific and technical findings, have led to the demonstration that the region is free of BSE. These early preventive actions have reliably protected the region from importing BSE-infected material. An integral part of the project to determine the BSE status of South America was the training of personnel, the incorporation of technology and the provision of updated information through close relationships with international organisations and prominent international researcher workers. Regional activities aimed at harmonising BSE prevention programmes, producing objective and transparent data on the equivalence of regional BSE status and facilitating regional and international trade have recently been launched. Maintaining the BSE-free status of the region must be given high priority by the beef agro-industrial sectors.

  20. The vegetation of the north-western Orange Free State, South Africa. 1. Physical environment

    Directory of Open Access Journals (Sweden)

    M. S. Kooij

    1990-12-01

    Full Text Available The physiography, geology, soil, land types and climate of the north-western Orange Free State are described. The description provides a contextual framework for the subsequent vegetation classification.

  1. Stress field modeling of northwestern South China Sea since 5.3 Ma and its tectonic significance

    Institute of Scientific and Technical Information of China (English)

    YANG Fengli; ZHOU Zuyi; ZHANG Na; LIU Ning; NI Bin

    2013-01-01

    Tectonically, the northwestern South China Sea (SCS) is located at the junction between three micro-plates, i.e., the Indochina, South China and Zhongsha-Xisha micro-plates, and involves three basins, i.e., the Yinggehai Basin, the Qiongdongnan Basin and Xisha Trough in the east, and the Zhongjiannan Basin in the south. Since the Pliocene (5.3 Ma), the Yinggehai Basin has experienced repeated accelerating subsidence, high thermal fluid, and widely developing mud-rich overpressure chambers, abundant mud diapers and crust-mantle mixed CO2. While a large central canyon was developed in the Qiongdongnan Basin, new rift occurred in the Xisha Trough. These characteristics demonstrate a single tectonic unit for the northwestern SCS, for which we have undertaken stress field modeling to understand its plate deformations and sedimen-tary responses. Our results demonstrate that an extension tectonic event occurred after 5.3 Ma in theYingge-hai-Qiongdongnan-Xisha trough area, which is characterized by thinner crust (3500 m). A new rift system subsequently was developed in this area;this event was mainly driven by the combined effects of different movement veloc-ity and direction of the three micro-plates, and the far-field effect of the continental collision between the Indian Plate and the Tibetan Plateau, and subduction of the Pacific Plate underneath the Eurasian Plate.

  2. Coordination of NEO Observers in South-America

    Science.gov (United States)

    Tancredi, G.

    At present the discovery of NEOs is concentrated in the Northern Hemisphere. None of the 6 existing survey programs can reach declinations below -30deg. Nevertheless, there are two small surveys ready to start in the near future in the southern hemisphere: an extension of the Catalina Sky Survey using the Uppsala Schmidt in Siding Spring and the Project BUSCA in Uruguay. Many of the NEOs discovered by the northern surveys could reach the southern sky, with declinations unreachable for a northern observer. Furthermore, the recovery of an asteroid in subsequent oppositions could come indistinctly in the northern and southern sky. A network of well-equipped observers in the southern region is then a must in a campaign to catalog the NEO population. In view of this situation, the Planetary Society, through its NEO grant, have already supported many observers in the Southern Hemisphere. The planetary science community in South America has considerably grown in the last 10 years. We have well-known research groups in Argentina, Brazil and Uruguay. Those groups have established many scientific links by exchanging graduate students and through several meetings. In particular, we have already hold two Workshop in Planetary Science in South America in 1999 (La Plata, Argentina) and 2000 (Montevideo, Uruguay) with more than 25 participants each. Recently, in February 2002, we organized a Workshop of NEO observers in Montevideo with the participation of more than 20 professional and amateurs observers from: Argentina: Obs. Ast. Felix Aguilar - Yale University (San Juan) and CRICYT (Mendoza); Brazil: Obs. Abraes de Moraes (San Pablo), Obs. Wykrota (Belo Horizonte) and Observatorio Nacional (Rio de Janeiro); Paraguay: Obs. Nacional de Asuncion and Sociedad de Estudios Astronómicos (Asunción) Uruguay: Depto. Astronomía - Fac. Ciencias, Obs. Ast. Los Molinos and Obs. Kappa Crucis (Montevideo). Among the resolutions of the Workshop, we highlight: * Creation of the "Asociaci

  3. Mechanisms for synoptic variations of atmospheric CO2 in North America, South America and Europe

    Directory of Open Access Journals (Sweden)

    I. T. Baker

    2008-12-01

    Full Text Available Synoptic variations of atmospheric CO2 produced by interactions between weather and surface fluxes are investigated mechanistically and quantitatively in midlatitude and tropical regions using continuous in-situ CO2 observations in North America, South America and Europe and forward chemical transport model simulations with the Parameterized Chemistry Transport Model. Frontal CO2 climatologies show consistently strong, characteristic frontal CO2 signals throughout the midlatitudes of North America and Europe. Transitions between synoptically identifiable CO2 air masses or transient spikes along the frontal boundary typically characterize these signals. One case study of a summer cold front shows CO2 gradients organizing with deformational flow along weather fronts, producing strong and spatially coherent variations. In order to differentiate physical and biological controls on synoptic variations in midlatitudes and a site in Amazonia, a boundary layer budget equation is constructed to break down boundary layer CO2 tendencies into components driven by advection, moist convection, and surface fluxes. This analysis suggests that, in midlatitudes, advection is dominant throughout the year and responsible for 60–70% of day-to-day variations on average, with moist convection contributing less than 5%. At a site in Amazonia, vertical mixing, in particular coupling between convective transport and surface CO2 flux, is most important, with advection responsible for 26% of variations, moist convection 32% and surface flux 42%. Transport model sensitivity experiments agree with budget analysis. These results imply the existence of a recharge-discharge mechanism in Amazonia important for controlling synoptic variations of boundary layer CO2, and that forward and inverse simulations should take care to represent moist convective transport. Due to the scarcity of tropical observations at the time of this study, results in Amazonia are not generalized for

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

    Science.gov (United States)

    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 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 Pangaea. Triassic extension is documented in the Central Cordillera of Colombia and Ecuador between ~ 240 Ma and ~ 215 Ma, although extension at this time has not been clearly identified in the Mérida Andes or the Santander Massif. Permian to Triassic cooling is not recorded in the structurally isolated Caparo Block in the southern Mérida Andes, suggesting that it may have constituted a distinct fault block in the Triassic. New fission track data from the Santander Massif suggest that it started exhuming at ~ 40 Ma during a period of accelerated convergence between the Nazca/Farallòn Plate and the western margin of South America. Exhumation in the Santander

  5. Final Gondwana breakup: The Paleogene South American native ungulates and the demise of the South America-Antarctica land connection

    Science.gov (United States)

    Reguero, Marcelo A.; Gelfo, Javier N.; López, Guillermo M.; Bond, Mariano; Abello, Alejandra; Santillana, Sergio N.; Marenssi, Sergio A.

    2014-12-01

    The biogeographic hypothesis more accepted today is that Antarctica (West Antarctica) and southern South America (Magellan region, Patagonia) were connected by a long and narrow causeway (Weddellian Isthmus) between the Antarctic Peninsula and South America since the Late Cretaceous (Campanian) until the Early Paleogene allowing terrestrial vertebrates to colonize new frontiers using this land bridge. Stratigraphically calibrated phylogenies including large, terrestrial native ungulates Litopterna and Astrapotheria taxa reveal long ghost lineages that extended into the Late Paleocene and provide evidence for the minimum times at which these "native ungulates" were present both on Antarctica and South America. Based on these results we estimate that the Weddellian Isthmus was functional as a land bridge until the Late Paleocene. Our data place the disconnection between Antarctica and South America in the Late Paleocene, indicating that the terrestrial faunistic isolation (Simpson's "splendid isolation") in South America begun at the end of the Paleocene (~ 56 to 57 m.y.). This faunistic isolation is documented to have occurred at least 25 Ma before the existence of deep-water circulation conditions in Drake Passage (~ 30 m.y.) based on the onset of seafloor spreading in the west Scotia Sea region. We hypothesize that in the early stages of extension (Late Paleocene, ~ 55 m.y.) a wide and relatively shallow epicontinental sea developed between the Antarctic Peninsula and South America drowning the Weddellian Isthmus and preventing the faunal interchange for obligate cursorial terrestrial forms.

  6. Seismicity of the Earth 1900-2007, Nazca Plate and South America

    Science.gov (United States)

    Rhea, Susan; Hayes, Gavin P.; Villaseñor, Antonio; Furlong, Kevin P.; Tarr, Arthur C.; Benz, Harley

    2010-01-01

    The South American arc extends over 7,000 km, from the Chilean triple junction offshore of southern Chile to its intersection with the Panama fracture zone, offshore the southern coast of Panama in Central America. It marks the plate boundary between the subducting Nazca plate and the South America plate, where the oceanic crust and lithosphere of the Nazca plate begin their decent into the mantle beneath South America. The convergence associated with this subduction process is responsible for the uplift of the Andes Mountains, and for the active volcanic chain present along much of this deformation front. Relative to a fixed South America plate the Nazca plate moves slightly north of eastwards at a rate varying from approximately 80 mm/yr in the south to approximately 70mm/yr in the north.

  7. A re-evaluation of the taphonomic methodology for the study of small mammal fossil assemblages of South America

    Science.gov (United States)

    Fernández, Fernando J.; Montalvo, Claudia I.; Fernández-Jalvo, Yolanda; Andrews, Peter; López, José Manuel

    2017-01-01

    The taphonomic methodology for the study of small mammal fossil was based mainly on actualistic studies of bones and teeth of insectivores (Soricidae, Talpidae, Erinaceidae) and rodents (Arvicolinae, Muridae) recovered from pellets of birds of prey and scats of carnivorous mammals from different places of North America, Europe and Africa. The digestive corrosion patterns on teeth of the South American rodents Sigmodontinae, Caviinae, Ctenomyidae and Abrocomidae, and the marsupials Monodelphini of central Argentina were observed. The comparison between the South American samples with the North American, African and European samples allowed us to establish similarities and differences in the digestive corrosion of the teeth. The main agreements have been recorded in the following groups: Arvicolinae with Caviinae and Abrocomidae; Murinae with Sigmodontinae; Soricidae, Talpidae and Erinaceidae with Monodelphini. However, the particular and simplified configuration of the molars of Ctenomyidae with thicker enamel and dentine exposed has promoted a new description of the categories of digestive corrosion. Likewise Muridae and Sigmodontinae molars, Ctenomyidae presents a delay in the appearance of signs of digestion with regard to other caviomorphs (Caviinae, Abrocomidae). This contribution may, therefore, be useful to know the origin of these South American faunas and the exact taphonomic agent that produced these assemblages. Finally, small mammal samples from an archaeo-palaeontological site from Northwestern Patagonia, Argentina, were studied in order to apply the new methodology emerged from the recent samples.

  8. Gnss Geodetic Monitoring as Support of Geodynamics Research in Colombia, South America

    Science.gov (United States)

    Mora-Paez, H.; Acero-Patino, N.; Rodriguez-Zuluaga, J. S.; Diederix, H.; Bohorquez-Orozco, O. P.; Martinez-Diaz, G. P.; Diaz-Mila, F.; Giraldo-Londono, L. S.; Cardozo-Giraldo, S.; Vasquez-Ospina, A. F.; Lizarazo, S. C.

    2013-05-01

    To support the geodynamics research at the northwestern corner of South America, GEORED, the acronym for "Geodesia: Red de Estudios de Deformación" has been adopted for the Project "Implementation of the National GNSS Network for Geodynamics" carried out by the Colombian Geological Survey, (SGC), formerly INGEOMINAS. Beginning in 2007, discussions within the GEORED group led to a master plan for the distribution of the base permanent GPS/GNSS station array and specific areas of interest for campaign site construction. The use of previously identified active faults as preferred structures along which stresses are transferred through the deformational area led to the idea of segmentation of the North Andes within Colombia into 20 tectonic sub-blocks. Each of the 20 sub-blocks is expected to have, at least, three-four permanent GPS/GNSS stations within the block along with construction of campaign sites along the boundaries. Currently, the GEORED Network is managing 46 continuously including: 40 GEORED GPS/GNSS continuously operating stations; 4 GNSS continuously operating stations provided by the COCONet (Continuously Operating Caribbean GPS Observational Network) Project; the Bogotá IGS GPS station (BOGT), installed in 1994 under the agreement between JPL-NASA and the SGC; and the San Andres Island station, installed in 2007 under the MOU between UCAR and the SGC. In addition to the permanent installations, more than 230 GPS campaign sites have been constructed and are being occupied one time per year. The Authority of the Panama Canal and the Escuela Politecnica de Quito have also provided data of 4 and 5 GPS/GNSS stations respectively. The GPS data are processed using the GIPSY-OASIS II software, and the GPS time series of daily station positions give fundamental information for both regional and local geodynamics studies. Until now, we have obtained 100 quality vector velocities for Colombia, 23 of them as part of the permanent network. The GPS/GNSS stations

  9. Weathering characteristics of the Lower Paleozoic black shale in northwestern Guizhou Province, south China

    Indian Academy of Sciences (India)

    Yang Liu; Jinchuan Zhang; Xuan Tang; Chao Yang; Shuai Tang

    2016-07-01

    The northwestern Guizhou in the Yangtze Craton of south China has a tremendous potential of shale gas resource. In this paper, we present results from major and trace elements, total organic carbon, mineralogical composition analysis and petrophysical parameters to characterise shale weathering features. Further, the differences of black shale between underground and outcrops have also been presented to examine the changes of black shale after weathering. Our results show that the trace elements of shale have varying degrees of loss in the weathering leaching process, both in Niutitang shale and Longmaxi shale, the loss of B, V, Ni, Cu, Zn and Ba is obvious, but the element migration quantity in the formeris greater than in the latter. Decomposition of minerals such as pyrite, feldspar and calcite result in the leaching of Na, Ca, Mg and Fe. The loss rate of total organic carbon (TOC) in black shales ranges from 18% to 70% with an average of 43%; moreover, the loss of organic carbon in samples with high TOC contentis larger than in those samples with low TOC content. Results following the testing of porosity and permeability show that porosity increases significantly after weathering but permeability changes little. Furthermore, the increment of porosity is greater in the Niutitang shale (with more sulphide minerals) than in the Longmaxi shale, suggesting that the oxidation of sulphide minerals may have led to the formationof an acidic environment, causing the other minerals in the black shale to weather more quickly, thus resulting in increased porosity. The content of clay minerals in the core samples is slightly lesser than the outcrop samples, but the TOC content in the core samples is greater and has a larger specific surface area. This suggest that the TOC content played a decisive role on the specific surface area of shale. In addition, changes in the black shale caused by the weathering process mainly depend on the mineral composition and the TOC content in

  10. Weathering characteristics of the Lower Paleozoic black shale in northwestern Guizhou Province, south China

    Science.gov (United States)

    Liu, Yang; Zhang, Jinchuan; Tang, Xuan; Yang, Chao; Tang, Shuai

    2016-07-01

    The northwestern Guizhou in the Yangtze Craton of south China has a tremendous potential of shale gas resource. In this paper, we present results from major and trace elements, total organic carbon, mineralogical composition analysis and petrophysical parameters to characterise shale weathering features. Further, the differences of black shale between underground and outcrops have also been presented to examine the changes of black shale after weathering. Our results show that the trace elements of shale have varying degrees of loss in the weathering leaching process, both in Niutitang shale and Longmaxi shale, the loss of B, V, Ni, Cu, Zn and Ba is obvious, but the element migration quantity in the former is greater than in the latter. Decomposition of minerals such as pyrite, feldspar and calcite result in the leaching of Na, Ca, Mg and Fe. The loss rate of total organic carbon (TOC) in black shales ranges from 18% to 70% with an average of 43%; moreover, the loss of organic carbon in samples with high TOC content is larger than in those samples with low TOC content. Results following the testing of porosity and permeability show that porosity increases significantly after weathering but permeability changes little. Furthermore, the increment of porosity is greater in the Niutitang shale (with more sulphide minerals) than in the Longmaxi shale, suggesting that the oxidation of sulphide minerals may have led to the formation of an acidic environment, causing the other minerals in the black shale to weather more quickly, thus resulting in increased porosity. The content of clay minerals in the core samples is slightly lesser than the outcrop samples, but the TOC content in the core samples is greater and has a larger specific surface area. This suggest that the TOC content played a decisive role on the specific surface area of shale. In addition, changes in the black shale caused by the weathering process mainly depend on the mineral composition and the TOC content

  11. T-Cell Lymphomas in South America and Europe

    Directory of Open Access Journals (Sweden)

    Monica Bellei

    2012-01-01

    Full Text Available Peripheral T-cell lymphomas are a group of rare neoplasms originating from clonal proliferation of mature post-thymic lymphocytes with different entities having specific biological characteristics and clinical features. As natural killer cells are closely related to T-cells, natural killer-cell lymphomas are also part of the group. The current World Health Organization classification recognizes four categories of T/natural killer-cell lymphomas with respect to their presentation: disseminated (leukemic, nodal, extranodal and cutaneous. Geographic variations in the distribution of these diseases are well documented: nodal subtypes are more frequent in Europe and North America, while extranodal forms, including natural killer-cell lymphomas, occur almost exclusively in Asia and South America. On the whole, T-cell lymphomas are more common in Asia than in western countries, usually affect adults, with a higher tendency in men, and, excluding a few subtypes, usually have an aggressive course and poor prognosis. Apart from anaplastic lymphoma kinase-positive anaplastic large cell lymphoma, that have a good outcome, other nodal and extranodal forms have a 5-year overall survival of about 30%. According to the principal prognostic indexes, the majority of patients are allocated to the unfavorable subset. In the past, the rarity of these diseases prevented progress in the understanding of their biology and improvements in the efficaciousness of therapy. Recently, international projects devoted to these diseases created networks promoting investigations on T-cell lymphomas. These projects are the basis of forthcoming cooperative, large scale trials to detail biologic characteristics of each sub-entity and to possibly individuate targets for new therapies.

  12. Intraplate stress field in South America from earthquake focal mechanisms

    Science.gov (United States)

    Assumpção, Marcelo; Dias, Fábio L.; Zevallos, Ivan; Naliboff, John B.

    2016-11-01

    We present an updated compilation of earthquake focal mechanisms in Brazil together with focal mechanisms from the sub-Andean region (mainly from global CMT catalogs). All earthquakes in the sub-Andean region show reverse (majority) or strike-slip faulting mechanisms. Focal mechanisms in Brazil show reverse, strike-slip and normal faulting. Focal mechanisms of nearby earthquakes in the same tectonic environment were grouped and inverted for the stress tensor. In the sub-Andean region, stresses are compressional, as expected, with the principal major compression (S1) roughly E-W, on average. A slight rotation of S1 can be observed and is controlled by the orientation of the Andean plateau. In the sub-Andean region, the intermediate principal stress (S2) is also compressional (i.e., larger than the lithostatic pressure, Sv), a feature that is not always reproduced in numerical models published in the literature. In mid-plate South America stresses seem to vary in nature and orientation. In SE Brazil and the Chaco-Pantanal basins, S1 tends to be oriented roughly E-W with S2 approximately equal to S3. This stress pattern changes to purely compressional (both SHmax and Shmin larger than Sv) in the São Francisco craton. A rotation of SHmax from E-W to SE-NW is suggested towards the Amazon region. Along the Atlantic margin, the regional stresses are very much affected by coastal effects (due to continent/ocean spreading stresses as well as flexural effects from sediment load at the continental margin). This coastal effect tends to make SHmax parallel to the coastline and Shmin (usually S3) perpendicular to the coastline. Few breakout data and in-situ measurements are available in Brazil and are generally consistent with the pattern derived from the earthquake focal mechanisms. Although numerical models of global lithospheric stresses tend to reproduce the main large-scale features in most mid-plate areas, the S1 rotation from ∼E-W in SE Brazil to SE-NW in the Amazon

  13. Diurnal variations in water vapor over Central and South America

    Science.gov (United States)

    Meza, Amalia; Mendoza, Luciano; Clara, Bianchi

    2017-04-01

    Diurnal variations in atmospheric integrated water vapor (IWV) are studied employing IWV estimates, with a 30 minutes sampling rate, derived from Global Navigation Satellite Systems (GNSS) observations during the period 2007-2013. The analysis was performed in 70 GNSS tracking sites (GPS + GLONASS) belonging to Central and South America, which have more than 5 years of data. The selected area involves different climate types, from polar to tropical, and diverse relieves, therefore the patterns of IWV diurnal variations are very different for each station. There are many processes that could induce diurnal variations in atmospheric water vapor (Dai et al, 1999 a,b), the most relevant causes are: surface evapotranspiration, atmospheric large-scale vertical motion, atmospheric low-level moisture convergence and precipitation and vertical mixing (which affects the vertical distribution of water vapor but does not affect the IWV). Firstly, our work study the main characteristics of the IWV diurnal cycle (and for surface temperature, T) obtained for all stations together, using Principal Component Analysis (PCA). First and second PCA modes highlight the global main behaviors of IWV variability for all stations. The first mode on IWV represent the 70% of the variability and could be related to the surface evapotranspiration, while the second mode (27 % of the variability) is practically in counter phase to T variability (its first mode represent the 97% of the variability), therefore this mode could be related to breeze regime. Then, every station is separately analyzed and seasonal and local variations (relative to the relives) are detected, these results spotlight, among other characteristics, the sea and mountain breeze regime. This presentation shows the first analysis of IWV diurnal cycle performed over Central and South America and another original characteristic is PCA technique employed to infer the results. Reference: Dai, A., K. E. Trenberth, and T. R. Karl

  14. Health outcomes among HIV-positive Latinos initiating antiretroviral therapy in North America versus Central and South America

    Science.gov (United States)

    Cesar, Carina; Koethe, John R; Giganti, Mark J; Rebeiro, Peter; Althoff, Keri N; Napravnik, Sonia; Mayor, Angel; Grinsztejn, Beatriz; Wolff, Marcelo; Padgett, Denis; Sierra-Madero, Juan; Gotuzzo, Eduardo; Sterling, Timothy R; Willig, James; Levison, Julie; Kitahata, Mari; Rodriguez-Barradas, Maria C; Moore, Richard D; McGowan, Catherine; Shepherd, Bryan E; Cahn, Pedro

    2016-01-01

    Introduction Latinos living with HIV in the Americas share a common ethnic and cultural heritage. In North America, Latinos have a relatively high rate of new HIV infections but lower rates of engagement at all stages of the care continuum, whereas in Latin America antiretroviral therapy (ART) services continue to expand to meet treatment needs. In this analysis, we compare HIV treatment outcomes between Latinos receiving ART in North America versus Latin America. Methods HIV-positive adults initiating ART at Caribbean, Central and South America Network for HIV (CCASAnet) sites were compared to Latino patients (based on country of origin or ethnic identity) starting treatment at North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) sites in the United States and Canada between 2000 and 2011. Cox proportional hazards models compared mortality, treatment interruption, antiretroviral regimen change, virologic failure and loss to follow-up between cohorts. Results The study included 8400 CCASAnet and 2786 NA-ACCORD patients initiating ART. CCASAnet patients were younger (median 35 vs. 37 years), more likely to be female (27% vs. 20%) and had lower nadir CD4 count (median 148 vs. 195 cells/µL, pAmerica have greater continuity of treatment but are at higher risk of death than Latinos in North America. Factors underlying these differences, such as HIV testing, linkage and access to care, warrant further investigation. PMID:26996992

  15. The first hypothelminorheic Crustacea (Amphipoda, Dogielinotidae, Hyalella from South America

    Directory of Open Access Journals (Sweden)

    Stella Rodrigues

    2012-11-01

    Full Text Available Most of known troglobiotic species occur in caves and subterranean environments from great depths. However, recently more attention has been given to other subterranean environments, such as the hypothelminorheic habitats. It comprises the most superficial among all subterranean habitats. This kind of environment is characterized by the constant presence of wet spots, absence of light and very particular abiotic characteristics, comprising unique species. The first hypothelminorheic Amphipoda from South America is here described, a new species of the genus Hyalella which occurs in a wetland on Southern Brazil. The new species differs from other troglobiotics of the genus by the presence of a curved seta on the inner ramus of uropod 1 and elongation of appendices, as the first pair of antennae and peraeopods 6 and 7. However, human impacts in the area where the new species occurs have changed heavily their habitat, which may have led the species to a critical level of threat or even extinction, demonstrating the fragility of this environment.a

  16. Robotic-assisted partial Nephrectomy: initial experience in South America

    Directory of Open Access Journals (Sweden)

    Gustavo C. Lemos

    2011-08-01

    Full Text Available OBJECTIVE:To report the initial outcomes of robotic-assisted partial nephrectomy in a tertiary center in South America. MATERIAL AND METHODS: From 11/2008 to 12/2009, a total of 16 transperitoneal robotic-assisted partial nephrectomies were performed in 15 patients to treat 18 kidney tumors. One patient with bilateral tumor had two procedures, while two patients with two synchronous unilateral tumors had a single operation to remove them. Eleven (73% patients were male and the right kidney was affected in 7 (46% patients. The median patient age and tumor size were 57 years old and 30 mm, respectively. Five (28% tumors were hilar and/or centrally located. RESULTS: The median operative time, warm ischemia time and estimated blood loss was 140 min, 27 min and 120 mL, respectively. Blood transfusion was required in one patient with bilateral tumor, and one additional pyelolithotomy was performed due to a 15mm stone located in the renal pelvis. The histopathology analysis showed 15 (83% malignant tumors, which 10 (67% were clear cell carcinoma. The median hospital stay was 72 hrs and no major complication was observed. CONCLUSION: Robotic-assisted partial nephrectomy is safe and represents a valuable option to perform minimally invasive nephron-sparing surgery.

  17. Lowland tapir distribution and habitat loss in South America

    Directory of Open Access Journals (Sweden)

    Jose Luis Passos Cordeiro

    2016-09-01

    Full Text Available The development of species distribution models (SDMs can help conservation efforts by generating potential distributions and identifying areas of high environmental suitability for protection. Our study presents a distribution and habitat map for lowland tapir in South America. We also describe the potential habitat suitability of various geographical regions and habitat loss, inside and outside of protected areas network. Two different SDM approaches, MAXENT and ENFA, produced relative different Habitat Suitability Maps for the lowland tapir. While MAXENT was efficient at identifying areas as suitable or unsuitable, it was less efficient (when compared to the results by ENFA at identifying the gradient of habitat suitability. MAXENT is a more multifaceted technique that establishes more complex relationships between dependent and independent variables. Our results demonstrate that for at least one species, the lowland tapir, the use of a simple consensual approach (average of ENFA and MAXENT models outputs better reflected its current distribution patterns. The Brazilian ecoregions have the highest habitat loss for the tapir. Cerrado and Atlantic Forest account for nearly half (48.19% of the total area lost. The Amazon region contains the largest area under protection, and the most extensive remaining habitat for the tapir, but also showed high levels of habitat loss outside protected areas, which increases the importance of support for proper management.

  18. [Hantavirus as important emerging agents in South America].

    Science.gov (United States)

    Ondoño, Andrés F; Levis, Silvana; Rodas, Juan D

    2011-01-01

    The dawning of the 20th century was marked by the emergence of new infectious disease agents and the appearance of others previously thought controlled. Both phenomena were possibly connected with ecological disturbances that led to the recognition of a dramatic climate change, of which the effects are only now becoming noticeable. Among the variety of agents to be considered, the many new viruses stand out, not only for their numerical proliferation, but also for their genetic versatility. It is this quality that provides them dexterity for evolving new strategies and adaptations to changing environmental conditions. Recently, some of the most ubiquitous and well-publicized viral agents in the American continents have been the rodent-borne viruses, and among these are the hantaviruses, etiological agents of pulmonary syndromes. Approximately 18 hantaviruses (belonging to the family Bunyaviridae), have been discovered in South America during the last 20 years, and although most of them cause persistent infections and subclinical infections in wild rodents (particularly members of the subfamily Sigmodontinae) and humans respectively; some others might also be highly lethal for humans. The goal herein is to review the state of the art regarding general aspects of hantaviruses and the diseases they cause around the world, highlighting the most recent findings in Colombia. Finally, the many unanswered questions will be recognized and highlighted concerning clinical importance and socio-economic impact of these agents on quality of public health in Colombia.

  19. A need for harmonized legislation: perspectives in South America.

    Science.gov (United States)

    de F Toledo, M Cecilia

    2014-08-01

    The harmonization of national food standards in South America has been undertaken by Argentina, Brazil, Paraguay and Uruguay within the Southern Common Market (MERCOSUR). Since food is among the most important commodities traded internationally, the harmonization of national food standards has been considered a priority. MERCOSUR countries have different laws governing food that are based, among other things, on historical, cultural and economic factors. Some regulations are complex and contain many controls while others are less developed and lack basic requirements. As a consequence, from the inception of preparing a common legislation through its adoption by the member countries, a long and difficult task has been foreseen. Although not immediately apparent, the difficulty in achieving consensus within MERCOSUR is not unlike that experience by the members of the European Union. Currently, food harmonization within MERCOSUR has been reached for issues where technical standards may represent serious trade barriers. These decisions have been based on Codex limentarius Commission guidelines and recommendations as well as on the European Union experience. This article will briefly discuss the current status of the MERCOSUR harmonization process with focus on issues related to food safety. A historical background of MERCOSUR and its institutional structure are included.

  20. Opportunities and challenges in developing gas markets in South America

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, Cristiano Boaventura [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The article has the objective of identifying and analyzing the key market levers and drivers, emerging issues and challenges in developing the gas markets in South America. In section 1, the paper provides an overview of the most relevant indicators in the natural gas markets of the region. Data such as natural gas proven reserves; production; consumption; trade movements (by pipeline and LNG) and main aspects of regulatory framework are shown. In section 2, some of the key challenges and opportunities in developing gas markets in the region are identified, including those relating to market integration, political aspects and the main players' investments. In section 3, possible strategies from governments and enterprises to overcome those challenges, and seize the potential opportunities of the region are examined. In section 4, the conclusions point to the potential of developing the gas markets as a means to diversify the energy sources in the region, fostering a successful process of economic growth and political integration in the area. (author)

  1. Interpreting satellite column observations of formaldehyde over tropical South America.

    Science.gov (United States)

    Palmer, Paul I; Barkley, Michael P; Kurosu, Thomas P; Lewis, Alastair C; Saxton, Julie E; Chance, Kelly; Gatti, Luciana V

    2007-07-15

    Space-borne column measurements of formaldehyde (HCHO), a high-yield oxidation product of volatile organic compounds (VOCs), represent important constraints for quantifying net regional fluxes of VOCs. Here, we interpret observed distributions of HCHO columns from the Global Ozone Monitoring Experiment (GOME) over tropical South America during 1997-2001. We present the first comparison of year-long in situ isoprene concentrations and fire-free GOME HCHO columns over a tropical ecosystem. GOME HCHO columns and in situ isoprene concentrations are elevated in the wet and dry seasons, with the highest values in the dry season. Previous analysis of the in situ data highlighted the possible role of drought in determining the elevated concentrations during the dry season, inferring the potential of HCHO columns to provide regional-scale constraints for estimating the role of drought on isoprene emissions. The agreement between the observed annual cycles of GOME HCHO columns and Along-Track Scanning Radiometer firecount data over the Amazon basin (correlations typically greater than 0.75 for a particular year) illustrates the potential of HCHO column to provide quantitative information about biomass burning emissions.

  2. CRED Gridded Bathymetry of South Gardner Pinnacles (100-015) in the Northwestern Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — File 100-015b is a 60-m ASCII grid of depth data collected near S Gardner Pinnacles in the Northwestern Hawaiian Islands as of May 2003. This grid has been produced...

  3. Distributed ice thickness and glacier volume in southern South America

    Science.gov (United States)

    Carrivick, Jonathan L.; Davies, Bethan J.; James, William H. M.; Quincey, Duncan J.; Glasser, Neil F.

    2016-11-01

    South American glaciers, including those in Patagonia, presently contribute the largest amount of meltwater to sea level rise per unit glacier area in the world. Yet understanding of the mechanisms behind the associated glacier mass balance changes remains unquantified partly because models are hindered by a lack of knowledge of subglacial topography. This study applied a perfect-plasticity model along glacier centre-lines to derive a first-order estimate of ice thickness and then interpolated these thickness estimates across glacier areas. This produced the first complete coverage of distributed ice thickness, bed topography and volume for 617 glaciers between 41°S and 55°S and in 24 major glacier regions. Maximum modelled ice thicknesses reach 1631 m ± 179 m in the South Patagonian Icefield (SPI), 1315 m ± 145 m in the North Patagonian Icefield (NPI) and 936 m ± 103 m in Cordillera Darwin. The total modelled volume of ice is 1234.6 km3 ± 246.8 km3 for the NPI, 4326.6 km3 ± 865.2 km3 for the SPI and 151.9 km3 ± 30.38 km3 for Cordillera Darwin. The total volume was modelled to be 5955 km3 ± 1191 km3, which equates to 5458.3 Gt ± 1091.6 Gt ice and to 15.08 mm ± 3.01 mm sea level equivalent (SLE). However, a total area of 655 km2 contains ice below sea level and there are 282 individual overdeepenings with a mean depth of 38 m and a total volume if filled with water to the brim of 102 km3. Adjusting the potential SLE for the ice volume below sea level and for the maximum potential storage of meltwater in these overdeepenings produces a maximum potential sea level rise (SLR) of 14.71 mm ± 2.94 mm. We provide a calculation of the present ice volume per major river catchment and we discuss likely changes to southern South America glaciers in the future. The ice thickness and subglacial topography modelled by this study will facilitate future studies of ice dynamics and glacier isostatic adjustment, and will be important for projecting water resources and

  4. The Paleoparasitology in Brazil and Findings in Human Remains from South America: A Review

    National Research Council Canada - National Science Library

    Shênia Patrícia Corrêa Novo; Luiz Fernando Ferreira

    2016-01-01

    .... In sequence, it is made a presentation of parasitological findings on human remains found in archaeological sites in South America, highlighting Brazil, Argentina, Chile, and Peru, where major discoveries have occurred...

  5. Tarphonomus, a new genus of ovenbird (Aves : Passeriformes : Furnariidae) from South America

    Science.gov (United States)

    Chesser, R.T.; Brumfield, R.T.

    2007-01-01

    Tarphonomus, a new genus of ovenbird (Aves: Passeriformes: Furnariidae) from South America, is described. Species included in the new genus, formerly placed in Upucerthia, are T. certhioides and T. harterti.

  6. A Diplodocid Sauropod Survivor from the Early Cretaceous of South America: e97128

    National Research Council Canada - National Science Library

    Pablo A Gallina; Sebastián Apesteguía; Alejandro Haluza; Juan I Canale

    2014-01-01

      Diplodocids are by far the most emblematic sauropod dinosaurs. They are part of Diplodocoidea, a vast clade whose other members are well-known from Jurassic and Cretaceous strata in Africa, Europe, North and South America...

  7. Map Service Showing Geology, Oil and Gas Fields, and Geologic Provinces of South America

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digitally compiled map includes geology, oil and gas fields, and geologic provinces of South America. The oil and gas map is part of a worldwide series released...

  8. Gene flow among Anopheles albimanus populations in Central America, South America, and the Caribbean assessed by microsatellites and mitochondrial DNA.

    Science.gov (United States)

    Molina-Cruz, Alvaro; de Mérida, Ana María P; Mills, Katherine; Rodríguez, Fernando; Schoua, Carolina; Yurrita, María Marta; Molina, Eduviges; Palmieri, Margarita; Black, William C

    2004-09-01

    Gene flow was examined among Anopheles albimanus populations from Cuba, Mexico, Guatemala, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, and Venezuela by examining variation at four microsatellite (MS) loci and a mitochondrial DNA (mtDNA) marker. There was little variation among Central American populations and weak isolation by distance was only observed with the MS loci. There was moderate to large variation between Central and South American populations, suggesting a barrier to gene flow between Central and South America. However, Panamanian and Pacific Costa Rican populations differed with respect to western Central America, suggesting that there may be another barrier within Central America. There was small to moderate variation among Caribbean and continental populations. Phylogenetic and diversity analyses of mtDNA indicate that more ancestral and diverse haplotypes were present in the Caribbean population, suggesting that current continental An. albimanus populations may have originated from the Caribbean.

  9. The Pleistocene Gomphotheres (Proboscidea) from South America: Diversity, Habitats and Feeding Ecology

    OpenAIRE

    Prado, José Luis; Alberdi Alonso, María Teresa; Azanza, Beatriz; Sánchez Chillón, Begoña; Frassinetti, D.

    2001-01-01

    Gomphotheres were recorded in South America from the early-middle Pleistocene (Ensenadan Land-mammal Age) to the late Pleistocene (Lujanian Land-mammal Age). They arrived in South America during the “Great American Biotic Interchange”. Only two genera are recognised: Cuvieronius, which has only one species, Cuvieronius hyodon; and Stegomastodon, which has two species, Stegomastodon waringi and Stegomastodon platensis. The small Cuvieronius utilised the Andean corridor and it was a...

  10. Natural gas commercialization in South America and its role as a regional integration factor

    Energy Technology Data Exchange (ETDEWEB)

    Stanton, Ed; Rotte, Jooste [Shell International Gas (Brazil)

    1994-12-31

    This paper reviews the development of the existing natural gas businesses in various parts of the world. Lessons that have been learnt are used as pointers to assist in further development of the gas potential in South America. The healthy prospects for gas in South America are reviewed together with the provisions that are essential for gas business development in the future. (author). 1 fig.

  11. Genetic Relationships Between Cercospora kikuchii Populations from South America and Japan.

    Science.gov (United States)

    Imazaki, I; Homma, Y; Kato, M; Vallone, S; Yorinori, J T; Henning, A A; Iizumi, H; Koizumi, S

    2006-09-01

    ABSTRACT A collection 160 isolates of Cercospora kikuchii was made from South America and 245 from Japan. DNA fingerprint patterns were analyzed based on amplified fragment length polymorphism among the sample isolates, dividing the isolates into seven lineages (I to VII). Partial nucleotide sequence analyses of the beta-tubulin gene supported this division into seven lineages. Lineages I and III commonly existed in South America and Japan. In all, 136 of the 160 isolates from South America and 223 of the 245 isolates from Japan belonged to lineage I, indicating that lineage I was the major lineage in each area; 5 isolates from South America and 8 isolates from Japan belonged to lineage III. Lineages II (12 isolates) and IV (2 isolates) were specific to Japan and lineages V (3 isolates), VI (1 isolate), and VII (15 isolates) specifically existed in South America. These results suggest that the population genetic structure of C. kikuchii was different between South America and Japan, but the dominance of lineage I was common between the two areas.

  12. Phylogenetic evidence of a new canine distemper virus lineage among domestic dogs in Colombia, South America.

    Science.gov (United States)

    Espinal, Maria A; Díaz, Francisco J; Ruiz-Saenz, Julian

    2014-08-06

    Canine distemper virus (CDV) is a highly contagious viral disease of carnivores affecting both wild and domestic populations. The hemagglutinin gene, encoding for the attachment protein that determines viral tropism, shows high heterogeneity among strains, allowing for the distinction of ten different lineages distributed worldwide according to a geographic pattern. We obtained the sequences of the full-length H gene of 15 wild-type CDV strains circulating in domestic dog populations from the Aburrá Valley, Colombia. A phylogenetic analysis of H gene nucleotide sequences from Colombian CDV viruses along with field isolates from different geographic regions and vaccine strains was performed. Colombian wild-type viruses formed a distinct monophyletic cluster clearly separated from the previously identified wild-type and vaccine lineages, suggesting that a novel genetic variant, quite different from vaccines and other lineages, is circulating among dog populations in the Aburrá Valley. We propose naming this new lineage as "South America 3". This information indicates that there are at least three different CDV lineages circulating in domestic and wild carnivore populations in South America. The first one, renamed Europe/South America 1, circulates in Brazil and Uruguay; the second, South America 2, appears to be restricted to Argentina; and the third, South America 3, which comprises all the strains characterized in this study, may also be circulating in other northern countries of South America.

  13. Evidence of two co-circulating genetic lineages of canine distemper virus in South America.

    Science.gov (United States)

    Panzera, Yanina; Calderón, Marina Gallo; Sarute, Nicolás; Guasco, Soledad; Cardeillac, Arianne; Bonilla, Braulio; Hernández, Martín; Francia, Lourdes; Bedó, Gabriela; La Torre, José; Pérez, Ruben

    2012-01-01

    Canine distemper virus (CDV) is the etiological agent of a multisystemic infection that affects different species of carnivores and is responsible for one of the main diseases suffered by dogs. Recent data have shown a worldwide increase in the incidence of the disease, including in vaccinated dog populations, which necessitates the analysis of circulating strains. The hemagglutinin (H) gene, which encodes the major antigenic viral protein, has been widely used to determine the degree of genetic variability and to associate CDVs in different worldwide circulating lineages. Here, we obtained the sequence of the first full-length H gene of field South American CDV strains and compared it with sequences of worldwide circulating field strains and vaccine viruses. In South America, we detect two co-circulating lineages with different prevalences: the Europe 1 lineage and a new South America 2 lineage. The Europe 1 lineage was the most prevalent in South America, and we suggest renaming it the Europe 1/South America 1 lineage. The South America 2 lineage was found only in Argentina and appears related to wild CDV strains. All South American CDV strains showed high amino-acid divergence from vaccine strains. This genetic variability may be a possible factor leading to the resurgence of distemper cases in vaccinated dog populations.

  14. First report of feline morbillivirus in South America.

    Science.gov (United States)

    Darold, Gabriela Molinari; Alfieri, Amauri Alcindo; Muraro, Lívia Saab; Amude, Alexandre Mendes; Zanatta, Rosana; Yamauchi, Kelly Cristiane Ito; Alfieri, Alice Fernandes; Lunardi, Michele

    2017-02-01

    Feline morbillivirus was first identified in healthy and diseased stray cats captured in Hong Kong. Recently, it was demonstrated that the virus circulates within cat populations in Japan, Italy, Germany, and the USA. Importantly, an association between feline morbillivirus infection and chronic kidney disease was suggested by histological analysis of kidney tissue of infected cats. The aim of this study was to verify the presence and examine the genetic diversity of feline morbilliviruses associated with infections of domestic cats in Brazil. Seventeen cats without clinical manifestations of urinary tract diseases from a multi-cat household and 35 random client-owned cats admitted to the Teaching Veterinary Hospital for a variety of reasons were evaluated for paramyxoviral infection and the presence of uropathy. A fragment of the paramyxoviral L gene was amplified from urine samples using a reverse transcription semi-nested PCR assay. For the first time, we detected a feline morbillivirus strain that was genetically related to viral strains previously characterized in Japan in urine samples from cats in South America, in Brazil. This together with the recent description of feline morbillivirus identification within cat populations in the USA, suggests a possible widespread distribution of this viral agent on the American continent. Our data demonstrated feline morbillivirus RNA shedding mostly in the urine of cats without clinical, laboratorial, or ultrasonographic signs of urinary tract diseases. In contrast to previously published findings that associated feline morbillivirus infection with chronic kidney disease, we did not observe a clear relationship between feline morbillivirus RNA shedding in urine and kidney disease in the cats evaluated.

  15. Climate Inferences from Geothermal Measurements in South America

    Science.gov (United States)

    Gurza Fausto, E.; Harris, R. N.; Montenegro, A.; Tassara, A.; Beltrami, H.

    2014-12-01

    Analysis of borehole temperature data have contributed significantly to estimating the last millennium surface temperature changes. Additionally, recent analysis have contributed to evaluate the Earth's energy balance by providing a quantitative value for the energy absorbed by the continents in the later part of the 20th century. Knowledge of the surface energy flux is important for understanding the solid Earth - atmosphere boundary condition, land cover changes, and their impact on regional and global climate models. We present data and analysis of 19 borehole temperature versus depth profiles from South America. The dataset includes 10 new borehole logs measured during 2012 at three sites in northern Chile (Vallenar, Sierra Gorda and Sierra Limon Verde). These new measurements complement six temperature logs measured during 1994 in the same region (sites near Michilla and Sierra Limon Verde; Springer et al., Tectonophysics, 1998) and four logs obtained from the NOAA Paleoclimatology Borehole Database located in Villa Staff, Toquepala and Talara in Peru. These data were analyzed for climate variability signals of the surface temperature and changes in the Earth's surface energy balance. The analysis suggests a cooling trend during the 19th century of approximately -0.5ºK. Furthermore, results show regionalized temperature changes in ground surface temperatures during the last 50 years with estimates of -0.4ºK in Vallenar, and approximately +1ºK in the Atacama Desert of Northern Chile. We place the results within the context of surface air temperature yearly means obtained from existing meteorological and proxy paleoclimatic data between Peru and Northern Chile. The use of geothermal measurements for climate variability studies provides a further understanding of the climatic and energy cycles of the Southern Hemisphere, where meteorological data can be scarce to non-existent.

  16. Diabetes in South and Central America: an update.

    Science.gov (United States)

    Aschner, Pablo; Aguilar-Salinas, Carlos; Aguirre, Loreto; Franco, Laercio; Gagliardino, Juan Jose; de Lapertosa, Sylvia Gorban; Seclen, Segundo; Vinocour, Mary

    2014-02-01

    The estimated population of the South and Central America (SACA) Region is 467.6 million and 64% is in the age range of 20-79 years but the population pyramid and age distribution are changing. The average prevalence of diabetes in the Region is 8.0% and is expected to reach 9.8% by the year 2035. Prevalence is much lower in rural settings than in urban and the differences attributed to lifestyle changes may be a target for intervention. The indigenous population is a particularly vulnerable group needing special attention. On average, 24% of the adult cases with diabetes are undiagnosed but in some countries this is still as high as 50%. Health expenditure due to diabetes in the Region is around 9% of the global total. Inadequate glycemic control, defined as HbA1c >7%, is a strong predictor of chronic complications which increase resource use in the Region and less than half of the patients enrolled in diabetes care programmes are at target. Fifty percent or more of the adult population is overweight/obese and around one third of the adult population has metabolic syndrome using regional cutoffs for waist circumference. The number of people with IGT is almost equal to those with diabetes presenting an additional challenge for prevention. Children with type 1 diabetes represent only 0.2% of the total population with diabetes but the incidence may be increasing. In many places they have limited access to insulin, and even when available, it is not used appropriately. The available epidemiological data provide the background to act in developing national diabetes programmes which integrate diabetes care with cardiovascular prevention and promote diabetes prevention as well.

  17. Land Use and climate change interactions in tropical South America

    Science.gov (United States)

    Swann, A. L. S.; Longo, M.; Knox, R. G.; Lee, E.; Moorcroft, P. R.

    2015-12-01

    Ongoing agricultural expansion in Amazonia and the surrounding areas of Brazil is expected to continue over the next several decades as global food demand increases. The transition of natural forest and savannah ecosystems to pastureland and agricultural crops is predicted to create warmer and drier atmospheric conditions than the native vegetation. Compounding this effect, climate change is likely to lead to reduced transpiration fluxes as plants become more water efficient under higher atmospheric carbon dioxide (CO2) levels. Here we investigate the expected impacts of predicted future land use on the climate of South America as well as the potential impacts of increasing CO2. We find that the climate response to land use change generally consistent with expectations from previous global modeling simulations with drier conditions resulting from deforestation, however the direct changes in precipitation are relatively small (on order of a few percent). Local drying from land use change is driven primarily by decreases in evapo-transpiration associated with the loss of forest, and concomitant increases in runoff. Significant changes in convectively available potential energy and convective inhibition during the transition to the wet season indicate that the decrease in surface latent heat flux is indeed leading to a drier atmosphere, however these changes occur around a mean climatological state that is already very favorable for convection, and thus lead to relatively small changes in precipitation. The physiological effects of increasing CO2 alone also drive a reduction in precipitation, which is compounded by radiation-driven circulation changes. If these land use changes were to occur under a background state of drier conditions, such as those predicted for the future global climate model experiments, this additional atmospheric drying driven by land use change may be sufficient to decrease precipitation more substantially.

  18. Recent crustal deformation in west-central South America

    Science.gov (United States)

    Pritchard, Matthew Earl

    I use interferometric synthetic aperture radar (InSAR) to create maps of crustal deformation along the coast and within the volcanic arc of central South America. I image deformation associated with six subduction zone earthquakes, four volcanic centers, at least one shallow crustal earthquake, and several salt flats. In addition, I constrain the magnitude and location of post-seismic deformation from the aforementioned subduction zone earthquakes. I combine InSAR observations with data from the Global Positioning System (GPS) and teleseismic data to explore each source of deformation. I use the observations to constrain earthquake and volcanic processes of this subduction zone, including the plumbing system of the volcanoes and the decadal along strike variations in the subduction zone earthquake cycle. I created interferograms of over 900 volcanoes in the central Andes spanning 1992--2002, and found four areas of deformation. I constrained the temporal variability of the deformation, the depth of the sources of deformation assuming a variety of source geometries and crustal structures, and the possible cause of the deformation. I do not observe deformation associated with eruptions at several volcanoes, and I discuss the possible explanations for this lack of deformation. In addition, I constrain the amount of co-seismic and post-seismic slip on the subduction zone fault interface from the following earthquakes: 1995 Mw 8.1 Antofagasta, Chile; 1996 Mw 7.7 Nazca, Peru; 1998 Mw 7.1 Antofagasta, Chile; and 2001 Mw 8.4 Arequipa, Peru. In northern Chile, I compare the location and magnitude of co-seismic slip from 5 Mw > 7 earthquakes during the past 15 years with the post-seismic slip distribution. There is little post-seismic slip from the 1995 and 1996 earthquakes relative to the 2001 event and other recent subduction zone earthquakes.

  19. Performance of a multi-RCM ensemble for South Eastern South America

    Energy Technology Data Exchange (ETDEWEB)

    Carril, A.F.; Menendez, C.G.; Salio, P. [Ciudad Universitaria, Ciudad Autonoma de Buenos Aires, Centro de Investigaciones del Mar y la Atmosfera (CIMA), CONICET-UBA, Buenos Aires (Argentina); Universidad de Buenos Aires, Departamento de Ciencias de la Atmosfera y los Oceanos (DCAO), FCEN, Buenos Aires (Argentina); UMI IFAECI/CNRS, Buenos Aires (Argentina); Remedio, A.R.C.; Jacob, D.; Pfeifer, S. [Max Planck Institute for Meteorology (MPI-M), Hamburg (Germany); Robledo, F.; Tencer, B. [Universidad de Buenos Aires, Departamento de Ciencias de la Atmosfera y los Oceanos (DCAO), FCEN, Buenos Aires (Argentina); Soerensson, A.; Zaninelli, P. [Ciudad Universitaria, Ciudad Autonoma de Buenos Aires, Centro de Investigaciones del Mar y la Atmosfera (CIMA), CONICET-UBA, Buenos Aires (Argentina); UMI IFAECI/CNRS, Buenos Aires (Argentina); Boulanger, J.P. [LOCEAN, UMR CNRS/IRD/UPMC, Paris (France); Castro, M. de; Sanchez, E. [Universidad de Castilla-La Mancha (UCLM), Toledo (Spain); Le Treut, H.; Li, L.Z.X. [Sciences de l' Environnement en Ile de France, Laboratoire de Meteorologie Dynamique (LMD), Institut-Pierre-Simon-Laplace et Ecole Doctorale, Paris (France); Penalba, O.; Rusticucci, M. [Universidad de Buenos Aires, Departamento de Ciencias de la Atmosfera y los Oceanos (DCAO), FCEN, Buenos Aires (Argentina); UMI IFAECI/CNRS, Buenos Aires (Argentina); Samuelsson, P. [Swedish Meteorological and Hydrological Institute (SMHI), Norrkoeping (Sweden)

    2012-12-15

    The ability of four regional climate models to reproduce the present-day South American climate is examined with emphasis on La Plata Basin. Models were integrated for the period 1991-2000 with initial and lateral boundary conditions from ERA-40 Reanalysis. The ensemble sea level pressure, maximum and minimum temperatures and precipitation are evaluated in terms of seasonal means and extreme indices based on a percentile approach. Dispersion among the individual models and uncertainties when comparing the ensemble mean with different climatologies are also discussed. The ensemble mean is warmer than the observations in South Eastern South America (SESA), especially for minimum winter temperatures with errors increasing in magnitude towards the tails of the distributions. The ensemble mean reproduces the broad spatial pattern of precipitation, but overestimates the convective precipitation in the tropics and the orographic precipitation along the Andes and over the Brazilian Highlands, and underestimates the precipitation near the monsoon core region. The models overestimate the number of wet days and underestimate the daily intensity of rainfall for both seasons suggesting a premature triggering of convection. The skill of models to simulate the intensity of convective precipitation in summer in SESA and the variability associated with heavy precipitation events (the upper quartile daily precipitation) is far from satisfactory. Owing to the sparseness of the observing network, ensemble and observations uncertainties in seasonal means are comparable for some regions and seasons. (orig.)

  20. Effects of Atlantic warm pool variability over climate of South America tropical transition zone

    Science.gov (United States)

    Ricaurte Villota, Constanza; Romero-Rodríguez, Deisy; Andrés Ordoñez-Zuñiga, Silvio; Murcia-Riaño, Magnolia; Coca-Domínguez, Oswaldo

    2016-04-01

    Colombia is located in the northwestern corner of South America in a climatically complex region due to the influence processes modulators of climate both the Pacific and Atlantic region, becoming in a transition zone between phenomena of northern and southern hemisphere. Variations in the climatic conditions of this region, especially rainfall, have been attributed to the influence of the El Nino Southern Oscillation (ENSO), but little is known about the interaction within Atlantic Ocean and specifically Caribbean Sea with the environmental conditions of this region. In this work We studied the influence of the Atlantic Warm Pool (AWP) on the Colombian Caribbean (CC) climate using data of Sea Surface Temperature (SST) between 1900 - 2014 from ERSST V4, compared with in situ data SIMAC (National System for Coral Reef Monitoring in Colombia - INVEMAR), rainfall between 1953-2013 of meteorological stations located at main airports in the Colombian Caribbean zone, administered by IDEAM, and winds data between 2003 - 2014 from WindSat sensor. The parameters analyzed showed spatial differences throughout the study area. SST anomalies, representing the variability of the AWP, showed to be associated with Multidecadal Atlantic Oscillation (AMO) and with the index of sea surface temperature of the North-tropical Atlantic (NTA), the variations was on 3 to 5 years on the ENSO scale and of approximately 11 years possibly related to solar cycles. Rainfall anomalies in the central and northern CC respond to changes in SST, while in the south zone these are not fully engage and show a high relationship with the ENSO. Finally, the winds also respond to changes in SST and showed a signal approximately 90 days possibly related to the Madden-Julian Oscillation, whose intensity depends on the CC region being analyzed. The results confirm that region is a transition zone in which operate several forcing, the variability of climate conditions is difficult to attribute only one, as ENSO

  1. Unraveling The Complex Interaction Between The Southern Caribbean, Northwest South America And The Pacific Plates During The Cenozoic

    Science.gov (United States)

    Villagomez, D.; Spikings, R.

    2013-05-01

    We have studied the prominent Sierra Nevada de Santa Marta Massif (the highest peak in the world whose local base is at sea level, ~5.75km) in Northern Colombia and we are interested in quantifying the thermal and tectonic history of the Northernmost Andes during the Cenozoic in order to understand the complex interaction between the Caribbean, the South American and the Pacific plates. In order to do so, apatite fission track data (by the LA-ICP-MS method) has been used, collected along several traverses and a single vertical profile within the massif. Our results show that the easternmost part of Sierra Nevada de Santa Marta exhumed at elevated rates (≥0.2 Km/My) during 65-58 Ma in response to the collision of the Caribbean Plateau with north-western South America. A second pulse of exhumation (≥0.32 Km/My) during 50-40 Ma was probably driven by the underthrusting of the Caribbean Plate beneath northern South America. More southern portions of the Sierra Nevada de Santa Marta (the Sierra Nevada Province) exhumed rapidly during 26-29 Ma (~0.7 Km/My), whereas farther north, the northwestermost corner of the Sierra Nevada de Santa Marta (the Santa Marta Province) exhumed at elevated rates during 30-25 Ma and 25-16 Ma. Our thermochronological data show that the highest exhumation rates within the Sierra Nevada de Santa Marta progressed towards the northwest via the propagation of NW-verging thrusts. The late Oligocene-Miocene exhumation was mainly a consequence of compression originating at the Pacific margin of South America that also gave rise to uplift and exhumation in other regions of Eastern Colombia (e.g. in the Santander Massif). Major continental faults such as the left-lateral Santa Marta-Bucaramanga Fault have played an important role transferring the deformation, Exhumation of the Sierra Nevada de Santa Marta Massif is not recorded after ~16 Ma, which is unexpected, given the high elevation and high erosive power of the climate, implying that rock and

  2. PREFACE: Introduction to the proceedings of Dynamics Days South America 2010

    Science.gov (United States)

    Macau, Elbert E. N.; Pereira, Tiago; Prado, Antonio F. B. A.; Turci, Luiz F. R.; Winter, Othon C.

    2011-03-01

    This proceedings presents selected contributions from the participants of South America Dynamics Days 2011, which was hosted by the National Institute for Space Research (INPE), Brazil, in July 2010. Dynamics Days was founded in 1980 and is the longest standing and most respected international series of meetings devoted to the field of dynamics and nonlinearity. Traditionally it has brought together researchers from a wide range of backgrounds - including physics, biology, engineering, chemistry and mathematics - for interdisciplinary research into nonlinear science. Dynamics Days South America 2010 marked the beginning of the South American branch of Dynamics Days. It brought together, for the first time in South America, researchers from a wide range of backgrounds who share a common interest in the theory and applications of nonlinear dynamics. Thus, South American researchers had a forum to promote regional as well as international scientific and technological exchange and collaboration especially, but not exclusively, on problems that are particularly relevant for the development of science and technology in the South American region. Furthermore, the conference also brought together prominent scientists from around the world to review recent developments in nonlinear science. This conference comprised plenary invited talks, minisymposia, contributed talks and poster sessions. The articles that are compiled here were chosen from among the works that were presented as contributed talks and posters. They represent a good selection which allows one to put issues that were discussed during the conference into perspective. It is possible to evaluate the success of an initiative by using several indices. In relation to attendees, the conference had 311 participants from 22 countries, who presented 341 works. About 86% of the participants came from South American countries. These figures allow one to classify this Dynamics Days conference as that with the greatest

  3. A plate tectonic-paleoceanographic hypothesis for Cretaceous source rocks and cherts of northern South America

    Energy Technology Data Exchange (ETDEWEB)

    Villamil, T.; Arango, C. (Univ. of Colorado, Boulder, CO (United States))

    1996-01-01

    New paleocontinental reconstructions show a northern migration of the South American Plate with respect to the paleoequator from the Jurassic to the Late Cretaceous. This movement caused the northern margin of South America to migrate from a position south to a position north of the paleoequator. Ekman transport generated net surface water movement towards the south during times when northern South America was south of the paleoequator. This situation favored downwelling and prevented Jurassic and earliest Cretaceous marine source rocks from being deposited. When northern South America was north of the paleoequator Ekman transport forced net water movement to the north favoring upwelling, paleoproductivity, and the deposition of one of the best marine source rocks known (the La Luna, Villeta, and equivalents). This plate tectonic paleoceanographic hypothesis explains the origin of hydrocarbons in northern South America. The stratigraphic record reflects this increase in paleoproductivity through time. This can be observed in facies (non-calcareous shales to calcareous shales to siliceous shales and finally to bedded cherts) and in changing planktic communities which were initially dominated by healthy calcareous foraminifer assemblages, followed by stressed foraminifer populations and finally by radiolarians. Total organic carbon and source rock quality were affected by this long term increase in paleoproductivity but also, and more markedly, by a punctuated sequence stratigraphic record dominated by low- frequency changes in relative sea level. The magnitude of transgressive episodes caused by rise in sea level determined the extent of source rock intervals and indirectly the content of organic carbon.

  4. A plate tectonic-paleoceanographic hypothesis for Cretaceous source rocks and cherts of northern South America

    Energy Technology Data Exchange (ETDEWEB)

    Villamil, T.; Arango, C. [Univ. of Colorado, Boulder, CO (United States)

    1996-12-31

    New paleocontinental reconstructions show a northern migration of the South American Plate with respect to the paleoequator from the Jurassic to the Late Cretaceous. This movement caused the northern margin of South America to migrate from a position south to a position north of the paleoequator. Ekman transport generated net surface water movement towards the south during times when northern South America was south of the paleoequator. This situation favored downwelling and prevented Jurassic and earliest Cretaceous marine source rocks from being deposited. When northern South America was north of the paleoequator Ekman transport forced net water movement to the north favoring upwelling, paleoproductivity, and the deposition of one of the best marine source rocks known (the La Luna, Villeta, and equivalents). This plate tectonic paleoceanographic hypothesis explains the origin of hydrocarbons in northern South America. The stratigraphic record reflects this increase in paleoproductivity through time. This can be observed in facies (non-calcareous shales to calcareous shales to siliceous shales and finally to bedded cherts) and in changing planktic communities which were initially dominated by healthy calcareous foraminifer assemblages, followed by stressed foraminifer populations and finally by radiolarians. Total organic carbon and source rock quality were affected by this long term increase in paleoproductivity but also, and more markedly, by a punctuated sequence stratigraphic record dominated by low- frequency changes in relative sea level. The magnitude of transgressive episodes caused by rise in sea level determined the extent of source rock intervals and indirectly the content of organic carbon.

  5. Conservation of placentation during the tertiary radiation of mammals in South America

    DEFF Research Database (Denmark)

    Carter, Anthony Michael; Mess, Andrea Maria

    2013-01-01

    and may have been present in the founder generation on arrival in South America. In conclusion, there is a dichotomy within Xenarthra but otherwise the ancient South American mammals do not show much variation in principal placental characters. Thus, the successful radiation of these three groups...

  6. Pesticide residues in fruits and vegetables from South America – A Nordic project

    DEFF Research Database (Denmark)

    Hjorth, Karen; Johansen, K.; Holen, B.;

    2011-01-01

    The aim of this study was to investigate the amount of pesticide residues in fruits and vegetables from South America. A total of 724 samples of 46 different fruits and vegetables from eight South American countries were collected in 2007. In 19% of the samples no residues were found, 72% of samp...

  7. What Do We Know about the Development of Creativity in South America?

    Science.gov (United States)

    Preiss, David D.; Grau, Valeska; Ortiz, Dominga; Bernardino, Michelle

    2016-01-01

    We review recent research about the development of creativity in South America focusing on studies of individual differences in creativity and educational and developmental studies of children and adolescents' creativity. Most South American researchers are influenced by mainstream psychometric approaches, although computational and cultural…

  8. Selected hydrologic data, Yampa River basin and parts of the White River basin, northwestern Colorado and south-central Wyoming

    Science.gov (United States)

    Giles, T.F.; Brogden, Robert E.

    1978-01-01

    Selected hydrologic data are presented from four energy-related projects conducted by the U.S. Geological Survey in the Yampa River basin and parts of the White River basin in northwestern Colorado and south-central Wyoming. Water-quality data during 1974 and 1975 and parts of 1976 for 129 ground-water sites and 119 surface-water sites are tabulated. For most samples, major cations, anions, and trace metals were analyzed. For the same time period, field measurements of specific conductance, temperature, and pH were made on 252 springs and wells. These samplings sites, as well as the locations of 20 climatological stations, 18 snow-course sites, and 43 surface-water gaging stations, are shown on maps. Geologic units that contain coal deposits or supply much of the water used for stock and domestic purposes in the area also are shown on a map. (Woodard-USGS)

  9. Seismicity of the Earth 1900-2013, seismotectonics of South America (Nazca Plate Region)

    Science.gov (United States)

    Hayes, Gavin P.; Smoczyk, Gregory M.; Benz, Harley M.; Furlong, Kevin P.; Villaseñor, Antonio

    2015-01-01

    The South American arc extends over 7,000 kilometers (km), from the Chilean margin triple junction offshore of southern Chile, to its intersection with the Panama fracture zone, offshore of the southern coast of Panama in Central America. It marks the plate boundary between the subducting Nazca plate and the South America plate, where the oceanic crust and lithosphere of the Nazca plate begin their descent into the mantle beneath South America. The convergence associated with this subduction process is responsible for the uplift of the Andes Mountains, and for the active volcanic chain present along much of this deformation front. Relative to a fixed South America plate, the Nazca plate moves slightly north of eastwards at a rate varying from approximately 80 millimeters/year (mm/yr) in the south, to approximately 65 mm/yr in the north. Although the rate of subduction varies little along the entire arc, there are complex changes in the geologic processes along the subduction zone that dramatically influence volcanic activity, crustal deformation, earthquake generation and occurrence all along the western edge of South America.

  10. Genomic Insights into the Ancestry and Demographic History of South America.

    Science.gov (United States)

    Homburger, Julian R; Moreno-Estrada, Andrés; Gignoux, Christopher R; Nelson, Dominic; Sanchez, Elena; Ortiz-Tello, Patricia; Pons-Estel, Bernardo A; Acevedo-Vasquez, Eduardo; Miranda, Pedro; Langefeld, Carl D; Gravel, Simon; Alarcón-Riquelme, Marta E; Bustamante, Carlos D

    2015-12-01

    South America has a complex demographic history shaped by multiple migration and admixture events in pre- and post-colonial times. Settled over 14,000 years ago by Native Americans, South America has experienced migrations of European and African individuals, similar to other regions in the Americas. However, the timing and magnitude of these events resulted in markedly different patterns of admixture throughout Latin America. We use genome-wide SNP data for 437 admixed individuals from 5 countries (Colombia, Ecuador, Peru, Chile, and Argentina) to explore the population structure and demographic history of South American Latinos. We combined these data with population reference panels from Africa, Asia, Europe and the Americas to perform global ancestry analysis and infer the subcontinental origin of the European and Native American ancestry components of the admixed individuals. By applying ancestry-specific PCA analyses we find that most of the European ancestry in South American Latinos is from the Iberian Peninsula; however, many individuals trace their ancestry back to Italy, especially within Argentina. We find a strong gradient in the Native American ancestry component of South American Latinos associated with country of origin and the geography of local indigenous populations. For example, Native American genomic segments in Peruvians show greater affinities with Andean indigenous peoples like Quechua and Aymara, whereas Native American haplotypes from Colombians tend to cluster with Amazonian and coastal tribes from northern South America. Using ancestry tract length analysis we modeled post-colonial South American migration history as the youngest in Latin America during European colonization (9-14 generations ago), with an additional strong pulse of European migration occurring between 3 and 9 generations ago. These genetic footprints can impact our understanding of population-level differences in biomedical traits and, thus, inform future medical

  11. Genomic Insights into the Ancestry and Demographic History of South America

    Science.gov (United States)

    Homburger, Julian R.; Moreno-Estrada, Andrés; Gignoux, Christopher R.; Nelson, Dominic; Sanchez, Elena; Ortiz-Tello, Patricia; Pons-Estel, Bernardo A.; Acevedo-Vasquez, Eduardo; Miranda, Pedro; Langefeld, Carl D.; Gravel, Simon; Alarcón-Riquelme, Marta E.; Bustamante, Carlos D.

    2015-01-01

    South America has a complex demographic history shaped by multiple migration and admixture events in pre- and post-colonial times. Settled over 14,000 years ago by Native Americans, South America has experienced migrations of European and African individuals, similar to other regions in the Americas. However, the timing and magnitude of these events resulted in markedly different patterns of admixture throughout Latin America. We use genome-wide SNP data for 437 admixed individuals from 5 countries (Colombia, Ecuador, Peru, Chile, and Argentina) to explore the population structure and demographic history of South American Latinos. We combined these data with population reference panels from Africa, Asia, Europe and the Americas to perform global ancestry analysis and infer the subcontinental origin of the European and Native American ancestry components of the admixed individuals. By applying ancestry-specific PCA analyses we find that most of the European ancestry in South American Latinos is from the Iberian Peninsula; however, many individuals trace their ancestry back to Italy, especially within Argentina. We find a strong gradient in the Native American ancestry component of South American Latinos associated with country of origin and the geography of local indigenous populations. For example, Native American genomic segments in Peruvians show greater affinities with Andean indigenous peoples like Quechua and Aymara, whereas Native American haplotypes from Colombians tend to cluster with Amazonian and coastal tribes from northern South America. Using ancestry tract length analysis we modeled post-colonial South American migration history as the youngest in Latin America during European colonization (9–14 generations ago), with an additional strong pulse of European migration occurring between 3 and 9 generations ago. These genetic footprints can impact our understanding of population-level differences in biomedical traits and, thus, inform future medical

  12. Genomic Insights into the Ancestry and Demographic History of South America.

    Directory of Open Access Journals (Sweden)

    Julian R Homburger

    2015-12-01

    Full Text Available South America has a complex demographic history shaped by multiple migration and admixture events in pre- and post-colonial times. Settled over 14,000 years ago by Native Americans, South America has experienced migrations of European and African individuals, similar to other regions in the Americas. However, the timing and magnitude of these events resulted in markedly different patterns of admixture throughout Latin America. We use genome-wide SNP data for 437 admixed individuals from 5 countries (Colombia, Ecuador, Peru, Chile, and Argentina to explore the population structure and demographic history of South American Latinos. We combined these data with population reference panels from Africa, Asia, Europe and the Americas to perform global ancestry analysis and infer the subcontinental origin of the European and Native American ancestry components of the admixed individuals. By applying ancestry-specific PCA analyses we find that most of the European ancestry in South American Latinos is from the Iberian Peninsula; however, many individuals trace their ancestry back to Italy, especially within Argentina. We find a strong gradient in the Native American ancestry component of South American Latinos associated with country of origin and the geography of local indigenous populations. For example, Native American genomic segments in Peruvians show greater affinities with Andean indigenous peoples like Quechua and Aymara, whereas Native American haplotypes from Colombians tend to cluster with Amazonian and coastal tribes from northern South America. Using ancestry tract length analysis we modeled post-colonial South American migration history as the youngest in Latin America during European colonization (9-14 generations ago, with an additional strong pulse of European migration occurring between 3 and 9 generations ago. These genetic footprints can impact our understanding of population-level differences in biomedical traits and, thus, inform

  13. Neurocysticercosos in South-Central America and the Indian Subcontinent: a comparative evaluation

    Directory of Open Access Journals (Sweden)

    Gagandeep Singh

    1997-09-01

    Full Text Available Neurocysticercosis is an important public health problem in South-Central America and South Asia. A review of the differences in epidemiological and clinical attributes of cysticercosis and taeniasis in South Central America and India, respectively, is undertaken in the present communication. Intestinal taeniasis is hyperendemic in several American countries. In comparison, the prevalence of Taenia solium infestation is lower in India. The clinical manifestations in several American neurocysticercosis series comprise epilepsy, intracranial hypertension and meningeal - racemose cysticercosis, in roughly equal proportions. An overwhelming majority of the Indian subjects present with seizures. The commonest pathological substrate of the disorder in Indian patients is the solitary parenchymal degenerating cyst. The reasons for the predominance of solitary forms in India, and of multilesional forms in South Central America are discussed. The magnitude of Taenia solium infestation and the frequency of pork consumption in a given population appear to influence the quantum of cyst load in affected individuals.

  14. A review of Tertiary climate changes in southern South America and the Antarctic Peninsula. Part 2: continental conditions

    Science.gov (United States)

    Le Roux, J. P.

    2012-03-01

    Climate changes in southern South America and the Antarctic Peninsula during the Tertiary show a strong correlation with ocean warming and cooling events, which are in turn related to tectonic processes. During periods of accelerated sea-floor spreading and mid-ocean ridge activity, sea-levels rose so that parts of the continents were flooded and forests were destroyed. However, this was balanced by the large-scale release of CO2 during volcanic outgassing and carbonate precipitation on the continental shelves, which caused rising air temperatures and the poleward expansion of (sub)tropical and temperate forests. Cooling episodes generally caused an increase in the north-south thermal gradient because of an equatorward shift in climate belts, so that the Westerly Winds intensified and brought higher rainfall to the lower latitudes. An increase in wind-blown dust caused temperatures to drop further by reflecting sunlight back into space. The rising Andes Range had a marked influence on climate patterns. Up to the middle Miocene it was still low enough to allow summer rainfall to reach central and north-central Chile, but after about 14 Ma it rose rapidly and effectively blocked the spill-over of moisture from the Atlantic Ocean and Amazon Basin. At this time, the cold Humboldt Current was also established, which together with the Andes helped to create the "Arid Diagonal" of southern South America stretching from the Atacama Desert to the dry steppes of Patagonia. This caused the withdrawal of subtropical forests to south-central Chile and the expansion of sclerophytic vegetation to central Chile. However, at the same time it intercepted more rain from the northeast, causing the effect of the South American monsoon to intensify in northwestern Argentina and southern Bolivia, where forest communities presently occur. In Patagonia, glaciation started as early as 10.5 Ma, but by 7 Ma had become a prominent feature of the landscape and continued apparently

  15. Ecological community traits and traditional knowledge shape palm ecosystem services in northwestern South America

    DEFF Research Database (Denmark)

    Cámara-Leret, Rodrigo; Paniagua-Zambrana, Narel; Balslev, Henrik

    2014-01-01

    Tropical rainforest ecosystems support the maximum expression of biocultural diversity on Earth and preserving them requires understanding and working with the needs of their inhabitants. Here, we com- bine traditional knowledge with ecological data to quantify cross-scale variation in the ecosys...

  16. Two new species of Pimelodidae from Northwestern South America (Pisces, Nematognathi)

    NARCIS (Netherlands)

    Mees, G.F.

    1978-01-01

    Since the publication of a paper on Auchenipteridae and Pimelodidae (Mees, 1974), I have received additional material of several of the genera there revised. This material includes a new species of Pseudopimelodus from Venezuela, increasing the number of species of that genus to six (two of which

  17. Summer precipitation projections over northwestern South America from CMIP5 models

    Science.gov (United States)

    Palomino-Lemus, Reiner; Córdoba-Machado, Samir; Gámiz-Fortis, Sonia Raquel; Castro-Díez, Yolanda; Esteban-Parra, María Jesús

    2015-08-01

    In this study, statistical downscaling (SD) models have been built using principal component regression (PCR) for simulating summer precipitation in Colombia during the period 1950-2010, and climate projections have been made for the period 2071-2100 by applying the previous SD models to the SLP outputs of five GCMs. For this, the principal components (PCs) of the SLP reanalysis data from NCEP were used as predictor variables and the observed gridded summer precipitation as predictands. The period 1950-1993 was used for calibration and 1994-2010 for validation. Bootstrap with replacement was applied to provide estimations of the statistical errors. All SD models performed reasonably well at regional scales, and the spatial distribution of the correlation coefficients between the predicted and observed gridded precipitation values shows high significant values (between 0.5 and 0.93) along the Andes range, north and north Pacific of Colombia. The ability of the GCMs to simulate the summer precipitation in Colombia, for the present climate (1971-2000), has been analyzed by calculating the differences between the simulated and observed precipitation values, with the result that the precipitation simulations made for the GCMs show strong biases. However, SD models applied to the SLP output from GCMs demonstrate their ability to faithfully reproduce the rainfall field. Finally, for summer precipitation projections in Colombia for the period 2071-2100, the SD models, recalibrated for the total period 1950-2010, have been applied to the SLP output from GCMs under the RCP2.6, RCP4.5, and RCP8.5 scenarios. The SD estimations show considerable differences with respect to SD present values, generally towards precipitation increases. The SD MIROC5, HAdGEM2-AO, and CESM1(CAM5) present significant changes in all the regions for both the RCP4.5 and RCP8.5 scenarios. So, for the RCP8.5 these models project changes between 12.85% and 18.32% for the NWC region, 6.73% and 10.02% for the SWC region, 6.16% and 14.76% for the NCC region, and 8.31% and 23.11% for the NC region. This last region, that presents the greatest increase (23.11%) for the SD MIROC5 also presents the greatest decrease (- 7.8% under the RCP8.5) for SD MPI-ESM-LR. For the RCP2.6, significant increases are found only for the NWC region with SD HadGEM2-AO (4.5%) and for the NC region with the SD CESM1(CAM5) (8.33%).

  18. Earth's Largest Meteorite Impact Craters discovered in South America?

    Science.gov (United States)

    Kellndorfer, J. M.; Schmidt-Falkenberg, H.

    2014-12-01

    Novel analysis of high resolution InSAR-based digital elevation data from the year 2001 Shuttle Radar Topography Mission combined with a recently produced dataset of pan-tropical vegetation height from ALOS-1 SAR and IceSAT/GLAS Lidar estimates led to the quasi-bald-Earth discovery of four sizable near-perfect circle arcs in South America under dense tropical forests ranging in length from 216 km to 441 km. Terrain elevation profiles of cross-sections across the arcs show a distinct vertical rising and falling in elevations of hundreds of meters over a horizontal distance of tens of kilometers. It is hypothesized that these sizable arcs and associated rim-like topographic terrain features are remnants of huge meteorite impact craters with diameters ranging from 770 km to 1,310 km, thus forming potentially the largest known impact carter structures discovered on Earth today. The potential impact crater rim structures are located north of the eastern Amazon River, in the coastal region of Recife and Natal, and in the Brazilian, Bolivian and Paraguayan border region encompassing the Pantanal. Elevation profiles, hillshades and gray-shaded elevation maps were produced to support the geomorphologic analysis. It is also speculated whether in three of the four potential impact craters, central uplift domes or peaks, which are typical for complex impact crater structures can be identified. The worlds largest iron ore mining area of Carajás in Para, Brazil, falls exactly in the center of the largest hypothesized circular impact crater showing topographic elevations similar to the rim structure discovered 655 km to the north-north-west. Based on the topographic/geomorphologic driven hypothesis, geologic exploration of these topographic features is needed to test whether indeed meteorite impact craters could be verified, what the more exact ellipsoidal shapes of the potential impact craters might be, and to determine when during geologic times the impacts would have taken

  19. Radon exposure in abandoned metalliferous mines of South America

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.A.R. da; Umisedo, N.; Yoshimura, E.M. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Lab. de Dosimetria; Anjos, R.M. [Universidade Federal Fluminense (LARA/UFF), Niteroi, RJ (Brazil). Inst. de Fisica. Lab. de Radioecologia; Valladares, D.L.; Velasco, H.; Rizzotto, M. [Universidad Nacional de San Luis (UNSL) (Argentina). Inst. de Matematica Aplicada San Luis

    2011-07-01

    Since the days of the Spanish and Portuguese conquerors, South America has been closely associated with the metalliferous ore mining. Gold, silver, tin, lead, tungsten, nickel, copper, and palladium ores have been explored over the last centuries. In addition, there has also been the development and promotion of other economic activities related to mining, as the underground mine tourism. A few works have been published on radon levels in the South American mining. In this study, we investigated the radon transport process and its health hazard in two exhausted and abandoned mines in San Luis Province, Argentina. These mines were chosen because they have different physical configurations in their cavities, features which can affect the air flow patterns and radon concentrations. La Carolina gold mine (32 deg 48' 0'' S, 66 deg 60' 0'' W) is currently a blind end system, corresponding to a horizontal excavation into the side of a mountain, with only a main adit. Los Condores wolfram mine (32 deg 33' 25'' S, 65 deg 15' 20'' W) is also a horizontal excavation into the side of a mountain, but has a vertical output (a shaft) at the end of the main gallery. Three different experimental methodologies were used. Radon concentration measurements were performed by CR-39 nuclear track detectors. The distribution of natural radionuclide activities ({sup 40}K, {sup 232}Th and {sup 238}U) was determined from rock samples collected along their main adits, using in laboratory gamma-ray spectrometry. The external gamma dose rate was evaluated using thermoluminescent dosimeters and a portable survey meter. The values for the {sup 222}Rn concentration ranged from 0.43 {+-} 0.04 to 1.48 {+-} 0.12 kBq/m{sup 3} in the Los Condores wolfram mine and from 1.8 {+-} 0.1 to 6.0{+-}0.5 kBq/m{sup 3} in the La Carolina gold mine, indicating that, in this mine, the radon levels exceed up to four times the action level of 1.5 kBq/m{sup 3

  20. Lg and Other Regional Phases in South America

    Science.gov (United States)

    1992-10-01

    efectos de los terremotos en la regi6n Andina (Proyecto SISRA) 11, 31-36. Grupo de trabajo (1979). Estructura geol6gica y geofisica de America del Sur...Preliminar para America del Sur: Programa para la mitigaci6n de los efectos de los terremotos en la regi6n Andina (Proyectc SISRA) 11, 37-41. Herraiz...Neotect6nico Preliminar para America del Sur: Programa 42 para la mitigaci6n de los efectos de los terremotos en la regi6n Andina (Proyecto SISRA), 11

  1. PHYLOGEOGRAPHY OF BATRACHOSPERMUM MACROSPORUM (BATRACHOSPERMALES, RHODOPHYTA) FROM NORTH AND SOUTH AMERICA(1).

    Science.gov (United States)

    Vis, Morgan L; Cameron Hodge, J; Necchi, Orlando

    2008-08-01

    Phylogeographic trends in Batrachospermum macrosporum Mont. were investigated using the mitochondrial intergenic spacer between the cytochrome oxidase subunit 2 and 3 genes (cox2-3). A total of 11 stream segments were sampled with seven in the coastal plain of North America and four in tropical areas of South America. Fifteen thalli were sampled from seven streams, 14 thalli from two streams, and eight thalli from two streams. There were 16 haplotypes detected using 149 individuals. Of the eight haplotypes from locations in North America, all were 334 base pairs (bp) in length, and of those from South America, five were 344 bp, and three were 348 bp. Two individual networks were produced: one for the haplotypes from North America and another for those from South America, and these could not be joined due to the large number of base pair differences. This split between haplotypes from North and South America was confirmed with sequence data of the rbcL gene. There was very little genetic variation among the haplotypes from the North American locations, leading us to hypothesize that these are fairly recent colonization events along the coastal plain. In contrast, there was high variation among haplotypes from South America, and it would appear that the Amazon serves as a center of diversity. We detected considerable variation in haplotypes among streams, but frequently, a single haplotype in an individual stream segment, which is consistent with data from previous studies of other batrachospermalean taxa, may suggest a single colonization event per stream.

  2. Why does the convergence rate between Nazca and South America decrease since the Neogene?

    Science.gov (United States)

    Quinteros, J.; Sobolev, S. V.

    2012-12-01

    The classic example of the poorly understood rapid change of tectonic plates motion is the increase and then decrease of the convergence rate between the Nazca and South America plates during the last 25-20 Myr that has coincided with the growth of the Andes Mountains. Currently, the decrease in convergence rate is explained either by the increasing load of the Andes or by the appearance of flat slab segments beneath South America. Here, we present an alternative view derived from a thermomechanical self-consistent (gravity driven) model of Nazca plate subduction. Reconstructions of global plate velocities suggest that before some 25 Ma subduction of the Faralon/Nazca plate was almost perfectly parallel to the coastline of South America south of 20°S. After some 22 Ma direction of subduction became almost perpendicular to the trench. Based on these data as well as seismic tomographic images, we assume that the tip of the oceanic slab was still in the upper mantle under the central and southern parts of South America till 22 Ma. We run 2D thermomechanical models of gravity driven subduction starting at 22 Ma in the 1200 km deep mantle domain considering all the most important phase transformations. In all our numerical experiments we get a large increment in convergence velocity related to the penetration of the tip of the slab into the mantle transition zone. The subduction velocity is later reduced when the slab interacts with the spinel/perovskite phase transition and underlying more viscous lower mantle. Our models fit quite well the observed variations of convergence rate and are consistent with seismic tomographic images of the Nazca plate beneath South America. In a number of experiments we also added thick crust and high topography of Andes. These experiments demonstrate that presence of the Andes does not affect much the convergence rate between Nazca and South America plates. From our models we conclude that the variations in the convergence rate between

  3. Geographically Sourcing Cocaine's Origin - Delineation of the Nineteen Major Coca Growing Regions in South America.

    Science.gov (United States)

    Mallette, Jennifer R; Casale, John F; Jordan, James; Morello, David R; Beyer, Paul M

    2016-03-23

    Previously, geo-sourcing to five major coca growing regions within South America was accomplished. However, the expansion of coca cultivation throughout South America made sub-regional origin determinations increasingly difficult. The former methodology was recently enhanced with additional stable isotope analyses ((2)H and (18)O) to fully characterize cocaine due to the varying environmental conditions in which the coca was grown. An improved data analysis method was implemented with the combination of machine learning and multivariate statistical analysis methods to provide further partitioning between growing regions. Here, we show how the combination of trace cocaine alkaloids, stable isotopes, and multivariate statistical analyses can be used to classify illicit cocaine as originating from one of 19 growing regions within South America. The data obtained through this approach can be used to describe current coca cultivation and production trends, highlight trafficking routes, as well as identify new coca growing regions.

  4. Arrival of Paleo-Indians to the Southern Cone of South America: New Clues from Mitogenomes

    OpenAIRE

    Paschou, Peristera; de Saint Pierre, Michelle; Gandini, Francesca; Perego, Ugo A.; Bodner, Martin; Gómez-Carballa, Alberto; Corach, Daniel; Angerhofer, Norman; Woodward, Scott R.; Semino, Ornella; Salas, Antonio; Parson, Walther; Moraga, Mauricio; Achilli, Alessandro; Torroni, Antonio

    2012-01-01

    With analyses of entire mitogenomes, studies of Native American mitochondrial DNA (MTDNA) variation have entered the final phase of phylogenetic refinement: the dissection of the founding haplogroups into clades that arose in America during and after human arrival and spread. Ages and geographic distributions of these clades could provide novel clues on the colonization processes of the different regions of the double continent. As for the Southern Cone of South America, this approach has rec...

  5. 40Ar/39Ar ages of seamount trachytes from the South China Sea and implications for the evolution of the northwestern sub-basin

    Institute of Scientific and Technical Information of China (English)

    Xiaohu Li; Jiabiao Li; Xing Yu; Chunsheng Wang; Fred Jourdan

    2015-01-01

    A chronological study of seamount rocks in the South China Sea basin provides a great opportunity to understand the expansion and evolution history of the sea basin. In this paper, we analyzed the 40Ar/39Ar age of trachytic samples collected from the Shuangfeng seamounts in the northwestern sub-basin of the South China Sea. The two samples yielded plateau ages of 23.80 ? 0.18 and 23.29 ? 0.22 Ma, respectively, which indicate magmatic activity in late Oligocene which helpful constraints the expansion time of the northwest sub-basin. Previous studies suggested that the northwestern sub-basin and southwestern sub-basin have experienced a relatively consistent expansion in the NWeSE direction followed by a late expansion of the eastern sub-basin. We concluded that the expansion of the northwestern sub-basin began prior to ca. 24 Ma, which also implicated magmatic events of a late or stop expansion of the northwestern sub-basin combined with our results of 40Ar/39Ar age data and previous geophysical data.

  6. 40Ar/39Ar ages of seamount trachytes from the South China Sea and implications for the evolution of the northwestern sub-basin

    Directory of Open Access Journals (Sweden)

    Xiaohu Li

    2015-07-01

    Full Text Available A chronological study of seamount rocks in the South China Sea basin provides a great opportunity to understand the expansion and evolution history of the sea basin. In this paper, we analyzed the 40Ar/39Ar age of trachytic samples collected from the Shuangfeng seamounts in the northwestern sub-basin of the South China Sea. The two samples yielded plateau ages of 23.80 ± 0.18 and 23.29 ± 0.22 Ma, respectively, which indicate magmatic activity in late Oligocene which helpful constraints the expansion time of the northwest sub-basin. Previous studies suggested that the northwestern sub-basin and southwestern sub-basin have experienced a relatively consistent expansion in the NW–SE direction followed by a late expansion of the eastern sub-basin. We concluded that the expansion of the northwestern sub-basin began prior to ca. 24 Ma, which also implicated magmatic events of a late or stop expansion of the northwestern sub-basin combined with our results of 40Ar/39Ar age data and previous geophysical data.

  7. Review of: El Niño influence over South America during the mid-holocene

    Directory of Open Access Journals (Sweden)

    T. Jorgetti

    2006-01-01

    Full Text Available This work reports on the relationship between the Pacific Ocean sea surface temperature variability and precipitation over South America in the IPSL coupled model simulations of the present and the 6 kyr Before Present (Mid-Holocene climate. The model results suggests that the control exerted by ENSO on precipitation in South America was less frequent in the Mid-Holocene compared to the present climate and that the spatial distribution of the ENSO influence is considerably different in the two periods.

  8. Brazil and the institutionalization of South America: from hemispheric estrangement to cooperative hegemony

    Directory of Open Access Journals (Sweden)

    Carlos Gustavo Poggio Teixeira

    2011-01-01

    Full Text Available This article argues that Brazil went from a posture of estrangement in relation to the hemispheric project represented by the Free Trade Area of the Americas (FTAA to a strategy of cooperative hegemony aimed at institutionalizing the South American space and increasing the costs of the FTAA for the United States. Although Brazil was initially isolated, US lack of leadership combined with events at the subregional level ended up turning the tide in the direction of Brazilian interests. These factors help to understand the current institutional configuration of South America.

  9. Risk for transfusion-transmitted infectious diseases in Central and South America.

    OpenAIRE

    Schmunis, G. A.; Zicker, F.; Pinheiro, F.; Brandling-Bennett, D.

    1998-01-01

    We report the potential risk for an infectious disease through tainted transfusion in 10 countries of South and Central America in 1993 and in two countries of South America in 1994, as well as the cost of reagents as partial estimation of screening costs. Of the 12 countries included in the study, nine screened all donors for HIV; three screened all donors for hepatitis B virus (HBV); two screened all donors for Trypanosoma cruzi; none screened all donors for hepatitis C virus (HCV); and six...

  10. Late Cretaceous-recent tectonic assembly of diverse crustal blocks in Central America, the Nicaraguan Rise, the Colombian Basin and northern South America as seen on a 1600-km-long, geologic and structural transect

    Science.gov (United States)

    Sanchez, J.; Mann, P.

    2015-12-01

    We have constructed a 1600-km-long transect from northern Honduras to northern Colombia that crosses northeastward-striking crustal blocks using a combination of offshore seismic data, gravity and magnetic data, well subsidence information, nearby outcrop information, and results from previous thermochronological, geochronological, geochemical and paleostress studies. The transect defines three major crustal and structural provinces: 1) Precambrian-Paleozoic, Chortis continental block whose northern edge is defined by the North America-Caribbean plate boundary. Events in this ~20-25-km-thick province include two major unconformities at the top of the Cretaceous and Eocene, associated southeast-dipping thrust faults related to collision of the Great Arc of the Caribbean (GAC) and Caribbean Large Igneous Province (CLIP) with the Chortis continental block. A third event is Eocene to recent subsidence and transtensional basins formed during the opening of the Cayman trough; 2) Late Cretaceous GAC and CLIP of oceanic arc and plateau origin, whose northern, deformed edge corresponds to the mapped Siuna belt of northern Nicaragua. This crustal province has a ~15-20-km-thick crust and is largely undeformed and extends across the Lower Nicaraguan Rise, Hess fault, to the southern limit of the Colombian basin where about 300 km of this province has been subducted beneath the accretionary wedge of the South Caribbean deformed belt of northwestern South America; and 3) Eocene to recent accretionary prism and intramontane basins on continental crust of northern South America, where Miocene accelerated exhumation and erosion of Paleogene and Cretaceous rocks reflect either shallow subduction of the CLIP or the Panama collisional event to the southwest.

  11. The Relation Between the Civil Society and the Governments in the Migratory Processes in South America

    OpenAIRE

    Mario Santillo

    2005-01-01

    This paper aims to point out the proposals presented to the governments, launched by the organizations working with migratory issues and human rights, whenever a meeting related to these issues has taken place in South America. In addition, this paper will also present the most relevant conclusions reached by South American governments in several annual conferences on migration issues. The most important topics are: human rights, the regularization of regional illegal migrant's migratory situ...

  12. Future Trends in Nutrient Export to the Coastal Waters of South America: Implications for Occurrence of Eutrophication

    NARCIS (Netherlands)

    Struijk, F.; Kroeze, C.

    2010-01-01

    We analyze future trends in nutrient export to the coastal waters of South America, with a special focus on the causes of nutrient export and their potential effects. Nutrient Export from Watersheds (NEWS) model results for South America are presented, including trends in human activities and the as

  13. Current Status and Future Prospects to Achieve Foot-and-Mouth Disease Eradication in South America.

    Science.gov (United States)

    Clavijo, A; Sanchez-Vazquez, M J; Buzanovsky, L P; Martini, M; Pompei, J C; Cosivi, O

    2017-02-01

    South America has a favourable position with respect to foot-and-mouth disease (FMD) compared with other FMD-affected regions due to the elimination of endemic clinical presentation of the disease. South America has reached the final stage of control and aims to eradicate the disease in the region under the provisions of the Hemispheric Program for the Eradication of FMD 2011-2020 (PHEFA). This programme aims at bringing eradication to completion, thereby eliminating the pool of foot-and-mouth disease genotypes active in South America. This plan includes a regional political agreement that provides strategies and technical guidelines for the eradication of foot-and-mouth disease from South America. It incorporates knowledge and experience regarding the disease's history and its connection with the different production systems, animal movement and trade. The Pan American Foot and Mouth Disease Center has led the control and eradication programmes, providing the framework for designing national and subregional programmes that have led to significant progress in controlling the disease in South America. The current situation is the result of several factors, including the proper implementation of a national control programmes, good veterinary infrastructure in most countries and public-private participation in the process of eradicating the disease. Notwithstanding the favourable health status, there are significant challenges for the goal of eradication. At this stage, South American countries should enhance their surveillance strategies particularly through the use of target or risk-based surveys that contribute to increase the degree of sensitivity in the search for viral circulation in the context of absence of clinical occurrence of FMD.

  14. Molecular typing of canine distemper virus strains reveals the presence of a new genetic variant in South America.

    Science.gov (United States)

    Sarute, Nicolás; Pérez, Ruben; Aldaz, Jaime; Alfieri, Amauri A; Alfieri, Alice F; Name, Daniela; Llanes, Jessika; Hernández, Martín; Francia, Lourdes; Panzera, Yanina

    2014-06-01

    Canine distemper virus (CDV, Paramyxoviridae, Morbillivirus) is the causative agent of a severe infectious disease affecting terrestrial and marine carnivores worldwide. Phylogenetic relationships and the genetic variability of the hemagglutinin (H) protein and the fusion protein signal-peptide (Fsp) allow for the classification of field strains into genetic lineages. Currently, there are nine CDV lineages worldwide, two of them co-circulating in South America. Using the Fsp-coding region, we analyzed the genetic variability of strains from Uruguay, Brazil, and Ecuador, and compared them with those described previously in South America and other geographical areas. The results revealed that the Brazilian and Uruguayan strains belong to the already described South America lineage (EU1/SA1), whereas the Ecuadorian strains cluster in a new clade, here named South America 3, which may represent the third CDV lineage described in South America.

  15. Health outcomes among HIV-positive Latinos initiating antiretroviral therapy in North America versus Central and South America

    Directory of Open Access Journals (Sweden)

    Carina Cesar

    2016-03-01

    Full Text Available Introduction: Latinos living with HIV in the Americas share a common ethnic and cultural heritage. In North America, Latinos have a relatively high rate of new HIV infections but lower rates of engagement at all stages of the care continuum, whereas in Latin America antiretroviral therapy (ART services continue to expand to meet treatment needs. In this analysis, we compare HIV treatment outcomes between Latinos receiving ART in North America versus Latin America. Methods: HIV-positive adults initiating ART at Caribbean, Central and South America Network for HIV (CCASAnet sites were compared to Latino patients (based on country of origin or ethnic identity starting treatment at North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD sites in the United States and Canada between 2000 and 2011. Cox proportional hazards models compared mortality, treatment interruption, antiretroviral regimen change, virologic failure and loss to follow-up between cohorts. Results: The study included 8400 CCASAnet and 2786 NA-ACCORD patients initiating ART. CCASAnet patients were younger (median 35 vs. 37 years, more likely to be female (27% vs. 20% and had lower nadir CD4 count (median 148 vs. 195 cells/µL, p<0.001 for all. In multivariable analyses, CCASAnet patients had a higher risk of mortality after ART initiation (adjusted hazard ratio (AHR 1.61; 95% confidence interval (CI: 1.32 to 1.96, particularly during the first year, but a lower hazard of treatment interruption (AHR: 0.46; 95% CI: 0.42 to 0.50, change to second-line ART (AHR: 0.56; 95% CI: 0.51 to 0.62 and virologic failure (AHR: 0.52; 95% CI: 0.48 to 0.57. Conclusions: HIV-positive Latinos initiating ART in Latin America have greater continuity of treatment but are at higher risk of death than Latinos in North America. Factors underlying these differences, such as HIV testing, linkage and access to care, warrant further investigation.

  16. A Remote Sensing Class Exercise To Study the Effects of "El Nino" in South America.

    Science.gov (United States)

    Moxey, Lucas Eduardo

    2002-01-01

    Describes an undergraduate physical science laboratory course exercising the utilization of satellite imagery for studying the floods that resulted in the Parana River region in South America during El Nino (1997-1998), and examines vegetation cover and spectral profiles from the study area in order to further understand and assess the changes…

  17. Two new species of Compsosoma Lacordaire from South America (Coleoptera: Cerambycidae: Lamiinae: Compsosomatini)

    Science.gov (United States)

    Two new species of Compsosoma Lacordaire are described from South America: Compsosoma oculata from Bolivia, Santa Cruz Department, Refugio Los Volcanes and Compsosoma marcelae from Peru, Amazonas Department, 3 km east of Bagua Grande. Compsosoma alboapicalis Breuning is synonymized with Desmiphorops...

  18. Rodent middens, a new method for Quaternary research in arid zones of South America

    Science.gov (United States)

    Betancourt, J.L.; Saavedra, B.

    2002-01-01

    In arid and semi-arid regions of South America, historical evidence for climate and vegetation change is scarce despite its importance for determining reference conditions and rates of natural variability in areas susceptible to modern desertification. Normal lines of evidence, such as pollen stratigraphies from lakes, are either rare or unobtainable in deserts; studies of late Quaternary vegetation history are few and generally inconclusive. This gap in knowledge may be corrected with discovery and development of fossil rodent middens in rocky environments throughout arid South America. These middens, mostly the work of Lagidium, Phyllotis, Abrocoma and Octodontomys, are rich in readily identifiable plant macrofossils, cuticles and pollen, as well as vertebrate and insect remains. In the North American deserts, more than 2,500 woodrat (Neotoma) middens analyzed since 1960 have yielded a detailed history of environmental change during the past 40,000 years. Preliminary work in the pre-puna, Monte and Patagonian Deserts of western Argentina, the Atacama Desert of northern Chile/southern Peru, the Mediterranean matorral of central Chile, and the Puna of the Andean altiplano suggest a similar potential for rodent middens in South America. Here we borrow from the North American experience to synthesize methodologies and approaches, summarize preliminary work, and explore the potential of rodent midden research in South America.

  19. Book review: Vetter, H. 2005. Terralog. Turtles of the World. Vol. 3. Central and South America

    Directory of Open Access Journals (Sweden)

    2006-12-01

    Full Text Available Book review: Vetter, H. 2005. Terralog. Turtles of the World. Vol. 3. Central and South America/Schildkröten der Welt Band 3. Mittel- und Südamerika: 1-128, color pictures 606 + 9. Edition Chimaira, Frankfurt, Germany.ISBN 3-930612-82-8; 29.7 x 20.8 cm

  20. Science Teacher Education in South America: The Case of Argentina, Colombia and Chile

    Science.gov (United States)

    Cofré, Hernán; González-Weil, Corina; Vergara, Claudia; Santibáñez, David; Ahumada, Germán; Furman, Melina; Podesta, María E.; Camacho, Johanna; Gallego, Rómulo; Pérez, Royman

    2015-01-01

    In this review, the main characteristics of science teacher education in three countries in South America, namely Argentina, Chile and Colombia, are examined. Although reforms toward constructivist and inquiry-based teaching in science instruction have been made in each of the three reviewed countries, each country demonstrates limitations in the…

  1. Rapid coastal spread of First Americans: novel insights from South America's Southern Cone mitochondrial genomes.

    Science.gov (United States)

    Bodner, Martin; Perego, Ugo A; Huber, Gabriela; Fendt, Liane; Röck, Alexander W; Zimmermann, Bettina; Olivieri, Anna; Gómez-Carballa, Alberto; Lancioni, Hovirag; Angerhofer, Norman; Bobillo, Maria Cecilia; Corach, Daniel; Woodward, Scott R; Salas, Antonio; Achilli, Alessandro; Torroni, Antonio; Bandelt, Hans-Jürgen; Parson, Walther

    2012-05-01

    It is now widely agreed that the Native American founders originated from a Beringian source population ~15-18 thousand years ago (kya) and rapidly populated all of the New World, probably mainly following the Pacific coastal route. However, details about the migration into the Americas and the routes pursued on the continent still remain unresolved, despite numerous genetic, archaeological, and linguistic investigations. To examine the pioneering peopling phase of the South American continent, we screened literature and mtDNA databases and identified two novel mitochondrial DNA (mtDNA) clades, here named D1g and D1j, within the pan-American haplogroup D1. They both show overall rare occurrences but local high frequencies, and are essentially restricted to populations from the Southern Cone of South America (Chile and Argentina). We selected and completely sequenced 43 D1g and D1j mtDNA genomes applying highest quality standards. Molecular and phylogeographic analyses revealed extensive variation within each of the two clades and possibly distinct dispersal patterns. Their age estimates agree with the dating of the earliest archaeological sites in South America and indicate that the Paleo-Indian spread along the entire longitude of the American double continent might have taken even Paleo-Indian migrations, by targeting, if possible, both the general mixed population of national states and autochthonous Native American groups, especially in South America.

  2. Gilles de la Tourette Syndrome—A Case Report from Guyana in South America

    Directory of Open Access Journals (Sweden)

    V. Eapen

    1992-01-01

    Full Text Available A case of the Gilles de la Tourette syndrome from Guyana in South America is presented. The patient had a positive family history as well as coprolalia, echolalia, and attention deficit disorder with hyperactivity. The family history and cross-cultural similarity emphasise the biological factors in the aetiology of the syndrome.

  3. Land use patterns and related carbon losses following deforestation in South America

    NARCIS (Netherlands)

    Sy, De V.; Herold, M.; Achard, F.; Beuchle, R.; Clevers, J.G.P.W.; Lindquist, E.; Verchot, L.

    2015-01-01

    Land use change in South America, mainly deforestation, is a large source of anthropogenic CO2 emissions. Identifying and addressing the causes or drivers of anthropogenic forest change is considered crucial for global climate change mitigation. Few countries however, monitor deforesta

  4. A rapid diversification of rainforest trees (Guatteria; Annonaceae) following dispersal from Central into South America.

    Science.gov (United States)

    Erkens, Roy H J; Chatrou, Lars W; Maas, Jan W; van der Niet, Timotheüs; Savolainen, Vincent

    2007-07-01

    Several recent studies have suggested that a substantial portion of today's plant diversity in the Neotropics has resulted from the dispersal of taxa into that region rather than vicariance, but more data are needed to substantiate this claim. Guatteria (Annonaceae) is, with 265 species, the third largest genus of Neotropical trees after Inga (Fabaceae) and Ocotea (Lauraceae), and its widespread distribution and frequent occurrence makes the genus an excellent model taxon to study diversification patterns. This study reconstructed the phylogeny of Guatteria and inferred three major biogeographical events in the history of the genus: (1) a trans-oceanic Miocene migration from Central into South America before the closing of the Isthmus of Panama; (2) a major diversification of the lineage within South America; and (3) several migrations of South American lineages back into Central America via the closed Panamanian land bridge. Therefore, Guatteria is not an Amazonian centred-genus sensu Gentry but a major Miocene diversification that followed its dispersal into South America. This study provides further evidence that migration into the Neotropics was an important factor in the historical assembly of its biodiversity. Furthermore, it is shown that phylogenetic patterns are comparable to those found in Ocotea and Inga and that a closer comparison of these genera is desirable.

  5. The sexual history of the global South: sexual politics in Africa, Asia and Latin America

    NARCIS (Netherlands)

    Wieringa, S.; Sívori, H.

    2013-01-01

    The Sexual History of the Global South explores the gap between sexuality studies and post-colonial cultural critique. Featuring twelve case studies, based on original historical and ethnographic research from countries in Africa, Asia, and Latin America, the book examines the sexual investments

  6. The sexual history of the global South: sexual politics in Africa, Asia and Latin America

    NARCIS (Netherlands)

    Wieringa, S.; Sívori, H.

    2013-01-01

    The Sexual History of the Global South explores the gap between sexuality studies and post-colonial cultural critique. Featuring twelve case studies, based on original historical and ethnographic research from countries in Africa, Asia, and Latin America, the book examines the sexual investments und

  7. Land use patterns and related carbon losses following deforestation in South America

    NARCIS (Netherlands)

    Sy, De V.; Herold, M.; Achard, F.; Beuchle, R.; Clevers, J.G.P.W.; Lindquist, E.; Verchot, L.

    2015-01-01

    Land use change in South America, mainly deforestation, is a large source of anthropogenic CO2 emissions. Identifying and addressing the causes or drivers of anthropogenic forest change is considered crucial for global climate change mitigation. Few countries however, monitor deforesta

  8. A Remote Sensing Class Exercise To Study the Effects of "El Nino" in South America.

    Science.gov (United States)

    Moxey, Lucas Eduardo

    2002-01-01

    Describes an undergraduate physical science laboratory course exercising the utilization of satellite imagery for studying the floods that resulted in the Parana River region in South America during El Nino (1997-1998), and examines vegetation cover and spectral profiles from the study area in order to further understand and assess the changes…

  9. Precipitation over Northern South America and Its Seasonal Variability as Simulated by the CMIP5 Models

    Directory of Open Access Journals (Sweden)

    Juan P. Sierra

    2015-01-01

    Full Text Available Northern South America is identified as one of the most vulnerable regions to be affected by climate change. Furthermore, recent extreme wet seasons over the region have induced socioeconomic impacts of wide proportions. Hence, the evaluation of rainfall simulations at seasonal and interannual time scales by the CMIP5 models is urgently required. Here, we evaluated the ability of seven CMIP5 models (selected based on literature review to represent the seasonal mean precipitation and its interannual variability over northern South America. Our results suggest that it is easier for models to reproduce rainfall distribution during boreal summer and fall over both oceans and land. This is probably due to the fact that during these seasons, incoming radiation and ocean-atmosphere feedbacks over Atlantic and Pacific oceans locate the ITCZ on the Northern Hemisphere, as suggested by previous studies. Models exhibit the worse simulations during boreal winter and spring, when these processes have opposite effects locating the ITCZ. Our results suggest that the models with a better representation of the oceanic ITCZ and the local low-level jets over northern South America, such as the Choco low-level jet, are able to realistically simulate the main features of seasonal precipitation pattern over northern South America.

  10. Evaluation of precipitation variability over northern South America based on CMIP5 historical model simulations

    Science.gov (United States)

    Vieira, S. C.; Sierra, J. P.; Arias, P. A.

    2014-12-01

    Northern South America is identified as one of the most vulnerable regions to be affected by climate change. Furthermore, recent extreme wet seasons over the region have caused diverse socio-economic consequences. Hence, the evaluation of the representation of local climate of rainfall simulations at intra-annual seasonal and inter-annual time scales by the CMIP5 models is urgently required, in order to identify and analyze projections of regional and local climate under a global climate change scenario. Here, we evaluate the ability of seven of the CMIP5 models (selected based on literature review) to represent the seasonal mean precipitation and its inter-annual variability over northern South America. Our results suggest that it is easier for models to reproduce rainfall distribution during boreal summer and fall over both oceans and land, since during these seasons, not only incoming radiation, but also ocean-atmosphere feedbacks over Atlantic and Pacific oceans, locate the ITCZ on the Northern Hemisphere. Conversely, models exhibit the worse simulations of the seasonal mean precipitation during boreal winter and spring, when these processes have opposite effects locating the ITCZ. Our results suggest that the models with a better representation of the oceanic ITCZ and the local low-level jets over northern South America, such as the Choco low-level jet, are able to realistically simulate the main features of seasonal precipitation pattern over northern South America.

  11. Land use change and ecosystem service provision in Pampas and Campos grasslands of southern South America

    NARCIS (Netherlands)

    Modernel Hristoff, Pablo; Rossing, W.A.H.; Corbeels, M.; Dogliotti, S.; Picasso, V.; Tittonell, P.

    2016-01-01

    New livestock production models need to simultaneously meet the increasing global demand for meat and preserve biodiversity and ecosystem services. Since the 16th century beef cattle has been produced on the Pampas and Campos native grasslands in southern South America, with only small amounts of ex

  12. Observation of near-inertial internal waves on the continental slope in the northwestern South China Sea

    Science.gov (United States)

    Zheng, Jie; Tian, Jiwei; Liang, Hui

    2017-04-01

    Based on nearly 3 months of moored acoustic Doppler current profiler records on the continental slope in the northwestern South China Sea (SCS) in 2006, this study examines temporal and vertical characteristics of near-inertial internal waves (NIW). Rotary frequency spectrum indicates that motions in the near-inertial frequency are strongly polarized, with clockwise (CW) energy exceeding counterclockwise (CCW) by about a factor of 10. Wavelet analysis exhibits an energy peak exceeding the 95% confidence level at the frequency of local inertial during the passage of typhoon Xangsane (24 September to 4 October). This elevated near-inertial kinetic energy (NIKE) event possesses about a 4 days delay correlation with the time integral of energy flux induced by typhoon, indicating an energy source of wind. Further analysis shows that the upward phase velocity of this event is 3.8 m h-1 approximately, corresponding to a vertical wavelength of about 125 m if not taking the redshift of local inertial frequency into account. Rotary vertical wavenumber spectrum exhibits the dominance of clockwise-with-depth energy, indicating downward energy propagation and implying a surface energy source. Dynamical modes suggest that mode 1 plays a dominant role at the growth stage of NIW, whereas major contribution is from higher modes during the penetration of NIKE into the ocean interior.

  13. Permian storm current-produced offshore bars from an ancient shelf sequence : Northwestern Karoo basin, republic of South Africa

    Science.gov (United States)

    Smith, A. M.; Zawada, P. K.

    The Ecca-Beaufort transition zone from the Karoo Basin comprises upward-coarsening sequences which are interpreted as prograding, storm-produced offshore bars. Eight facies are recognised: (A) dark-grey shale, (B) thinly interbedded siltstone and mudstone, (C) thinly interbedded siltstone and very fine-grained sandstone, (D) blue-grey coarse-grained siltstone, (E) low-angle truncated and flat-laminated sandstone, (F) wave-rippled sandstone, (G) planar cross-bedded sandstone, (H) intraformational clay-pellet conglomerate. Four sub-environments are recognised, these being: (1) the bar crest which comprises proximal tempestites, (2) the bar slope consisting of soft-sediment deformed siltstone, (3) the bar fringe/ margin which is composed of storm layers and offshore siltstones and (4) the interbar/offshore environment comprising siltstone and distal storm layers. These bars formed in response to wave and storm processes and migrated across a muddy shelf environment. The orientation of bars was probably coast-parallel to subparallel with respect to the inferred north-northwest-south-southeast coastline. These proposed, storm-produced bars acted as major depo-centres within the shelf setting of the study area. As shelf sediments are recorded from almost the entire northwestern Karoo Basin it is anticipated that bar formation was an important sedimentary factor in the deposition of the sediments now referred to as the Ecca-Beaufort transition zone.

  14. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States

    Science.gov (United States)

    Rebich, R.A.; Houston, N.A.; Mize, S.V.; Pearson, D.K.; Ging, P.B.; Evan, Hornig C.

    2011-01-01

    SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  15. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States.

    Science.gov (United States)

    Rebich, Richard A; Houston, Natalie A; Mize, Scott V; Pearson, Daniel K; Ging, Patricia B; Evan Hornig, C

    2011-10-01

    SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%).

  16. Volatile Substance Misuse Among High School Students in South America

    Science.gov (United States)

    Hynes-Dowell, Marya; Mateu-Gelabert, Pedro; Barros, Helena Maria Taunhauser; Delva, Jorge

    2012-01-01

    This article summarizes data from a 2004 study of over 300,000 high school students (aged 13–18 years) in nine South American countries. A probabilistic sample targeted urban secondary schools, utilizing a self-administered questionnaire on prevalence and frequency of substance use. Multivariate analysis showed that volatile substances were the first or second most commonly reported substances used after alcohol and cigarettes in all countries (lifetime prevalence range: 2.67% [Paraguay] to 16.55% [Brazil]). Previous studies have highlighted volatile substance misuse among street children, whereas this study demonstrates that it is common among South American high school students. PMID:21609142

  17. Monte Verde: seaweed, food, medicine, and the peopling of South America.

    Science.gov (United States)

    Dillehay, Tom D; Ramírez, C; Pino, M; Collins, M B; Rossen, J; Pino-Navarro, J D

    2008-05-09

    The identification of human artifacts at the early archaeological site of Monte Verde in southern Chile has raised questions of when and how people reached the tip of South America without leaving much other evidence in the New World. Remains of nine species of marine algae were recovered from hearths and other features at Monte Verde II, an upper occupational layer, and were directly dated between 14,220 and 13,980 calendar years before the present ( approximately 12,310 and 12,290 carbon-14 years ago). These findings support the archaeological interpretation of the site and indicate that the site's inhabitants used seaweed from distant beaches and estuarine environments for food and medicine. These data are consistent with the ideas that an early settlement of South America was along the Pacific coast and that seaweeds were important to the diet and health of early humans in the Americas.

  18. Geology and hydrocarbon accumulations in the deepwater of the northwestern South China Sea-with focus on natural gas

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenfeng; SUN Zhipeng; ZHANG Daojun; ZHU Jitian; LI Xushen; HUANG Baojia; GUO Minggang; JIANG Rufeng

    2015-01-01

    The deepwater of the northwestern South China Sea is located in the central to southern parts of the Qiongdongnan Basin (QDN Basin), which is a key site for hydrocarbon exploration in recent years. In this study, the authors did a comprehensive analysis of gravity-magnetic data, extensive 3D seismic survey, cores and cuttings, paleontology and geochemical indexes, proposed the mechanism of natural gas origin, identified different oil and gas systems, and established the model of hydrocarbon accumulations in the deep-water region. Our basin tectonic simulation indicates that the evolution of QDN Basin was controlled by multiple-phased tectonic movements, such as Indochina-Eurasian Plate collision, Tibetan Uplift, Red River faulting and the expansion of the South China Sea which is characterized by Paleogene rifting, Neogene depression, and Eocene intensive faulting and lacustrine deposits. The drilling results show that this region is dominated by marine-terrestrial transitional and neritic-bathyal facies from the early Oligocene. The Yacheng Formation of the early Oligocene is rich in organic matter and a main gas-source rock. According to the geological-geochemical data from the latest drilling wells, Lingshui, Baodao, Changchang Sags have good hydrocarbon-generating potentials, where two plays from the Paleogene and Neogene reservoirs were developed. Those reservoirs occur in central canyon structural-lithologic trap zone, Changchang marginal trap zone and southern fault terrace of Baodao Sag. Among them, the central canyon trap zone has a great potential for exploration because the various reservoir-forming elements are well developed, i.e., good coal-measure source rocks, sufficient reservoirs from the Neogene turbidity sandstone and submarine fan, faults connecting source rock and reservoirs, effective vertical migration, late stage aggregation and favorable structural–lithological composite trapping. These study results provide an important scientific basis

  19. Regional Policy Frameworks of Social Solidarity Economy in South America

    NARCIS (Netherlands)

    M. Saguier; Z.W. Brent

    2014-01-01

    markdownabstract__Abstract__ This paper looks at how the social and solidarity economy (SSE) discourse has been deployed at a regional level by the Union of South American Nations (UNASUR) and Southern American Common Market (MERCOSUR), and the implications of these new policy frameworks for the ad

  20. On the importance of cascading moisture recycling in South America

    NARCIS (Netherlands)

    Zemp, D.C.; Schleussner, C.F.; Barbosa, H.M.J.; Van der Ent, R.J.; Donges, J.F.; Heinke, J.; Sampaio, G.; Rammig, A.

    2014-01-01

    Continental moisture recycling is a crucial process of the South American climate system. In particular, evapotranspiration from the Amazon basin contributes substantially to precipitation regionally as well as over other remote regions such as the La Plata basin. Here we present an in-depth analysi

  1. How do Biomass Burning Carbon Monixide Emissions from South America influence Satellite Observed Columns over Africa?

    Science.gov (United States)

    Krol, M. C.; van Leeuwen, T. T.; Aouizerats, B.; van der Werf, G.

    2015-12-01

    Large amounts of Carbon Monoxide (CO) are emitted during biomass burning events. These emissions severely perturb the atmospheric composition. For this reason, satellite observations of CO can help to constrain emissions from biomass burning. Other sources of CO, such as the production of CO from naturally emitted non-methane hydrocarbons, may interfere with CO from biomass burning and inverse modeling efforts to estimate biomass burning emissions have to account for these CO sources. The atmospheric lifetime of CO varies from weeks to months, depending on the availability of atmospheric OH for atmospheric oxidation of CO to carbon dioxide. This means that CO can be transported over relatively long distances. It also implies that satellite-observed CO does not necessarily originate from the underlying continent, but may be caused by distant emissions transported to the observation location. In this presentation we focus on biomass burning emissions from South America and Southern Africa during 2010. This year was particularly dry over South America with a large positive anomaly in biomass burning in the 2010 burning season (July-October). We will adress the question how CO plumes from South America biomass burning influence satellite observations from the Infrared Atmospheric Sounding Interferometer (IASI) instrument over Southern Africa. For this we employ the TM5 atmospheric chemistry model, with 1x1 degree zoom resolutions over Africa and South America. Also, we use the TM5-4DVAR code to estimate CO biomass burning emissions using IASI CO observations. The accompanying image shows IASI CO oberservations over Africa on August 27, 2010, compared to the columns simulated with TM5. Clear signs of intercontinental transport from South America are visible over the Southermost region.

  2. Lg and Other Regional Phases in South America

    Science.gov (United States)

    1991-10-23

    90-0298, ADA232087 58 60 Centro Regional de Sismologia, CERESIS (1985). Mapa Neotect6nico Preliminar de America del Sur, Proyecto SISRA, Instituto...report is written. It is annexed to the report. 61 ATENUACION DE LAS FASES DE CORTO PERIODO P, Li, Lg y Rg A TRAVES DE PERU - BOLIV[A, REGISTRADAS EN...Peru , reyitradas in L~a Pat - 8alvla (LP9). L~a velocidad promedio (km/s) oara !as fases consideradas as: P U L9 R h!70 km 7.73±0.21 .. 4±0.0001 3.54

  3. South America and the proliferation of biological weapons

    Directory of Open Access Journals (Sweden)

    Tatiana Coutto

    2013-04-01

    Full Text Available This article focuses on the role of regional institutions and political practices in strengthening multilateral disarmament and non-proliferation regimes. Particular attention is devoted to coordination between Brazil and Argentina with a view to forging a "South American position" vis-à-vis the Biological and Toxins Weapons Convention (BTWC. Empirical evidence suggests that informal arrangements between the two countries were capable of involving other South American leaders and promoting the exchange of information among different groups of states, most notably during the 2006 BTWC review conference. This paper also sheds light on the identification of specific features that allow for increasing visibility and actorness of regional powers in promoting universality of multilateral security regimes (MSR, as well as the limitations faced by these players.

  4. Placentation in Sigmodontinae: a rodent taxon native to South America

    DEFF Research Database (Denmark)

    Favaron, Phelipe O; Carter, Anthony Michael; Ambrosio, Carlos E;

    2011-01-01

    ABSTRACT: BACKGROUND: Sigmondontinae, known as "New World rats and mice," is a large subfamily of Cricetidae for which we herein provide the first comprehensive investigation of the placenta. METHODS: Placentas of various gestational ages ranging from early pregnancy to near term were obtained fo...... subfamily of South American rodents. We note, however, that some of these rodents can be captive bred and recommend that future studies focus on the study of time dated pregnancies....

  5. Acculturation Strategies Among South Asian Immigrants: The Mediators of Atherosclerosis in South Asians Living in America (MASALA) Study.

    Science.gov (United States)

    Needham, Belinda L; Mukherjee, Bhramar; Bagchi, Pramita; Kim, Catherine; Mukherjea, Arnab; Kandula, Namratha R; Kanaya, Alka M

    2017-04-01

    In the past, epidemiologic research on acculturation and health has been criticized for its conceptual ambiguity and simplistic measurement approaches. This study applied a widely-used theoretical framework from cross-cultural psychology to identify acculturation strategies among South Asian immigrants in the US and to examine sociodemographic correlates of acculturation strategies. Data were from the Mediators of Atherosclerosis in South Asians Living in America study. We used latent class analysis to identify groups of individuals that were similar based on cultural attitudes and behaviors. We used latent class regression analysis to examine sociodemographic correlates of acculturation strategies. We found that South Asian immigrants employed three acculturation strategies, including separation (characterized by a relatively high degree of preference for South Asian culture over US culture), assimilation (characterized by a relatively high degree of preference for US culture over South Asian culture), and integration (characterized by a similar level of preference for South Asian and US cultures). Respondents with no religious affiliation, those with higher levels of income, those who lived a greater percentage of their lives in the US, and those who spoke English well or very well were less likely to use the separation strategy than the assimilation or integration strategies. Using epidemiologic cohort data, this study illustrated a conceptual and methodological approach that addresses limitations of previous research on acculturation and health. More work is needed to understand how the acculturation strategies identified in this study affect the health of South Asian immigrants in the US.

  6. South America energy integration: regulatory prerequisites; Integracao energetica da America do Sul: condicionantes regulatorios

    Energy Technology Data Exchange (ETDEWEB)

    Tiryaki, Gisele Ferreira [Universidade de Salvador (UNIFACS), BA (Brazil)], e-mail: gisele_fsilva@unifacsmbr; Tiryaki, Ahmet [Anadolu Univ., Yunus Emre Campus, Eskisehir (Turkey)], e-mail: ahmettiryaki@anadolu.edu.tr

    2008-07-01

    This paper presents the results of a comparative analysis of the various regulatory systems from the South American countries with potential participations in projects of energetic integration, specifying the main factors which can implement projects of international trading of electricity and natural gas in the region.

  7. Some preliminary results of a worldwide seismicity estimation: a case study of seismic hazard evaluation in South America

    Directory of Open Access Journals (Sweden)

    C. V. Christova

    2000-06-01

    Full Text Available Global data have been widely used for seismicity and seismic hazard assessment by seismologists. In the present study we evaluate worldwide seismicity in terms of maps of maximum observed magnitude (Mmax, seismic moment (M 0 and seismic moment rate (M 0S. The data set used consists of a complete and homogeneous global catalogue of shallow (h £ 60 km earthquakes of magnitude MS ³ 5.5 for the time period 1894-1992. In order to construct maps of seismicity and seismic hazard the parameters a and b derived from the magnitude-frequency relationship were estimated by both: a the least squares, and b the maximum likelihood, methods. The values of a and b were determined considering circles centered at each grid point 1° (of a mesh 1° ´1° and of varying radius, which starts from 30 km and moves with a step of 10 km. Only a and b values which fulfill some predefined conditions were considered in the further procedure for evaluating the seismic hazard maps. The obtained worldwide M max distribution in general delineates the contours of the plate boundaries. The highest values of M max observed are along the circum-Pacific belt and in the Himalayan area. The subduction plate boundaries are characterized by the largest amount of M 0 , while areas of continental collision are next. The highest values of seismic moment rate (per 1 year and per equal area of 10 000 km 2 are found in the Southern Himalayas. The western coasts of U.S.A., Northwestern Canada and Alaska, the Indian Ocean and the eastern rift of Africa are characterized by high values of M 0 , while most of the Pacific subduction zones have lower values of seismic moment rate. Finally we analyzed the seismic hazard in South America comparing the predicted by the NUVEL1 model convergence slip rate between Nazca and South America plates with the average slip rate due to earthquakes. This consideration allows for distinguishing between zones of high and low coupling along the studied convergence

  8. Seismology in South America; an interview with Alberto Giesecke

    Science.gov (United States)

    Spall, H.

    1980-01-01

    Dr. Alberto A. Giesecke is head of the Instituto Geofisico del Peru, in Lima, Peru, and Director of Centro Regional de Sismologia para America del Sur (CERESIS). The center is dedicated to the coordination and promotion of earthquake hazard mitigation. Dr. Giesecke was President of the National Research Council of Peru and currently is a member of the Board of Directors of the National Institute for Industrial Technological Research and Standards and of the National Institute for Research and Training in Telecommunications. He presided over the Organizing Committee for the General Assemblies of the International Association for Seismology and Physics of the Earth's interor and the International Union for Radio Science held in Lima, Peru, in 1973 and 1975, respectively. 

  9. Middle Miocene near trench volcanism in northern Colombia: A record of slab tearing due to the simultaneous subduction of the Caribbean Plate under South and Central America?

    Science.gov (United States)

    Lara, M.; Cardona, A.; Monsalve, G.; Yarce, J.; Montes, C.; Valencia, V.; Weber, M.; De La Parra, F.; Espitia, D.; López-Martínez, M.

    2013-08-01

    Field, geochemical, geochronological, biostratigraphical and sedimentary provenance results of basaltic and associated sediments northern Colombia reveal the existence of Middle Miocene (13-14 Ma) mafic volcanism within a continental margin setting usually considered as amagmatic. This basaltic volcanism is characterized by relatively high Al2O3 and Na2O values (>15%), a High-K calc-alkaline affinity, large ion lithophile enrichment and associated Nb, Ta and Ti negative anomalies which resemble High Al basalts formed by low degree of asthenospheric melting at shallow depths mixed with some additional slab input. The presence of pre-Cretaceous detrital zircons, tourmaline and rutile as well as biostratigraphic results suggest that the host sedimentary rocks were deposited in a platform setting within the South American margin. New results of P-wave residuals from northern Colombia reinforce the view of a Caribbean slab subducting under the South American margin. The absence of a mantle wedge, the upper plate setting, and proximity of this magmatism to the trench, together with geodynamic constraints suggest that the subducted Caribbean oceanic plate was fractured and a slab tear was formed within the oceanic plate. Oceanic plate fracturing is related to the splitting of the subducting Caribbean Plate due to simultaneous subduction under the Panama-Choco block and northwestern South America, and the fast overthrusting of the later onto the Caribbean oceanic plate.

  10. Isotope chronostratigraphy of OCS well south Timbalier block 198, northwestern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Trainor, D.M.; Williams, D.F.

    1989-03-01

    Isotope chronostratigraphy is a modern technique for deriving a high-resolution geochronology for sediments of the outer continental shelf (OCS)-slope of the western gulf of Mexico. The release of proprietary stable isotope data from OCS exploration well South Timbalier Block 198 enables the first public presentation of specific isotopic data compared to previously established global and regional composite isotope records. The oxygen isotope type records for the Pliocene-Pleistocene for both the global oceans and western Gulf of Mexico are based on deep-sea cores and numerous exploration wells. The type record shown for the western Gulf of Mexico is a revised composite record defining 133 oxygen isotope stages from 0 to 4 m.y. This regional type record is directly comparable to the global composite isotope record. The oxygen isotope record for the well was derived utilizing two different foraminiferal species. The isotopic composition of the planktonic foraminifera Globigerinoides ruber was used in the upper 8000 ft of the well. The benthic foraminifera Uvigerina was examined in the lower 5000 ft where G. ruber was not present. This combined oxygen isotope record for the well, when integrated with the available biostratigraphy, enabled the recognition of 47 isotope stages of the Pliocene-Pleistocene section of the well and an additional series of glacial-interglacial cycles in the late Miocene. The isotope chronostratigraphy enabled the recognition of two hiatuses spanning the time interval from /delta//sup 18/O stage 93 at 2.76 Ma and from /delta//sup 18/O stage 131 at 3.9 Ma to the late Miocene at approximately 5 Ma. This high-resolution geochronology for OCS well South Timbalier Block 198 provides detailed information on sedimentation accumulation rates in this area.

  11. Molecular characterization of adenovirus circulating in Central and South America during the 2006–2008 period

    Science.gov (United States)

    García, Josefina; Sovero, Merly; Laguna‐Torres, Victor Alberto; Gomez, Jorge; Chicaiza, Wilson; Barrantes, Melvin; Sanchez, Felix; Jimenez, Mirna; Comach, Guillermo; De Rivera, Ivette L.; Agudo, Roberto; Arango, Ana E.; Barboza, Alma; Aguayo, Nicolas; Kochel, Tadeusz J.

    2009-01-01

    Background  Human Adenoviruses are recognized pathogens, causing a broad spectrum of diseases. Serotype identification is critical for epidemiological surveillance, detection of new strains and understanding of HAdvs pathogenesis. Little data is available about HAdvs subtypes in Latin America. Methods  In this study, we have molecularly characterized 213 adenoviruses collected from ILI presenting patients, during 2006‐08, in Central and South America. Results  Our results indicate that 161(76%) adenoviruses belong to subgroup C, 45 (21%) to subgroup B and 7 (3%) to subtype E4. PMID:19903214

  12. Institutional Status of BRICS and Pragmatic Cooperation:The Case of South America

    Directory of Open Access Journals (Sweden)

    Ernani Contipelli

    2015-05-01

    Full Text Available As a group formed by emerging powers, the BRICS is characterized by its particular profile: a pragmatic politic strategythat presents contradictory actions between its members. Internal cooperation among the BRICS members is becomingmore “institutional” with the creation of its financial institutions, the New Development Bank (NDB and the ContingencyReserve Agreement (CRA. These have led the group to a next stage in its history without changing its essence. The NDBhas been created to mobilize resources for infrastructure and sustainable development projects in emerging and developingcountries, and the CRA has been established to provide liquidity to countries experiencing difficulties in their balance ofpayment and to head off future economic crises. Many developing countries are closely observing these financial institutions.South America appears particularly interested to take advantage of them by attracting investments and obtainingloans from BRICS members in order to develop infrastructure in their countries and to build more informal relationshipswith foreign partners with reduced political commitments. For South America, the BRICS is an example of a pragmaticformula for cooperation in contrast to the modus operandi of traditional powers. In other words, poor countries would havean alternative to the International Monetary Fund and World Bank. Relations between the BRICS and South America arecharacterized by a pragmatic approach that reflects the “way of being” of the group and the necessities of modernization ofthe region. This article analyzes the particular relationship that BRICS is establishing with the countries of South Americausing its institutional status and pragmatic approach.

  13. Eocene primates of South America and the African origins of New World monkeys

    Science.gov (United States)

    Bond, Mariano; Tejedor, Marcelo F.; Campbell, Kenneth E.; Chornogubsky, Laura; Novo, Nelson; Goin, Francisco

    2015-04-01

    The platyrrhine primates, or New World monkeys, are immigrant mammals whose fossil record comes from Tertiary and Quaternary sediments of South America and the Caribbean Greater Antilles. The time and place of platyrrhine origins are some of the most controversial issues in primate palaeontology, although an African Palaeogene ancestry has been presumed by most primatologists. Until now, the oldest fossil records of New World monkeys have come from Salla, Bolivia, and date to approximately 26 million years ago, or the Late Oligocene epoch. Here we report the discovery of new primates from the ?Late Eocene epoch of Amazonian Peru, which extends the fossil record of primates in South America back approximately 10 million years. The new specimens are important for understanding the origin and early evolution of modern platyrrhine primates because they bear little resemblance to any extinct or living South American primate, but they do bear striking resemblances to Eocene African anthropoids, and our phylogenetic analysis suggests a relationship with African taxa. The discovery of these new primates brings the first appearance datum of caviomorph rodents and primates in South America back into close correspondence, but raises new questions about the timing and means of arrival of these two mammalian groups.

  14. Biogeographic range expansion into South America by Coccidioides immitis mirrors New World patterns of human migration

    Science.gov (United States)

    Fisher, Matthew C.; Koenig, Gina L.; White, Thomas J.; San-Blas, Gioconda; Negroni, Ricardo; Alvarez, Isidro Gutiérrez; Wanke, Bodo; Taylor, John W.

    2001-01-01

    Long-distance population dispersal leaves its characteristic signature in genomes, namely, reduced diversity and increased linkage between genetic markers. This signature enables historical patterns of range expansion to be traced. Herein, we use microsatellite loci from the human pathogen Coccidioides immitis to show that genetic diversity in this fungus is geographically partitioned throughout North America. In contrast, analyses of South American C. immitis show that this population is genetically depauperate and was founded from a single North American population centered in Texas. Variances of allele distributions show that South American C. immitis have undergone rapid population growth, consistent with an epidemic increase in postcolonization population size. Herein, we estimate the introduction into South America to have occurred within the last 9,000–140,000 years. This range increase parallels that of Homo sapiens. Because of known associations between Amerindians and this fungus, we suggest that the colonization of South America by C. immitis represents a relatively recent and rapid codispersal of a host and its pathogen. PMID:11287648

  15. Eocene primates of South America and the African origins of New World monkeys.

    Science.gov (United States)

    Bond, Mariano; Tejedor, Marcelo F; Campbell, Kenneth E; Chornogubsky, Laura; Novo, Nelson; Goin, Francisco

    2015-04-23

    The platyrrhine primates, or New World monkeys, are immigrant mammals whose fossil record comes from Tertiary and Quaternary sediments of South America and the Caribbean Greater Antilles. The time and place of platyrrhine origins are some of the most controversial issues in primate palaeontology, although an African Palaeogene ancestry has been presumed by most primatologists. Until now, the oldest fossil records of New World monkeys have come from Salla, Bolivia, and date to approximately 26 million years ago, or the Late Oligocene epoch. Here we report the discovery of new primates from the ?Late Eocene epoch of Amazonian Peru, which extends the fossil record of primates in South America back approximately 10 million years. The new specimens are important for understanding the origin and early evolution of modern platyrrhine primates because they bear little resemblance to any extinct or living South American primate, but they do bear striking resemblances to Eocene African anthropoids, and our phylogenetic analysis suggests a relationship with African taxa. The discovery of these new primates brings the first appearance datum of caviomorph rodents and primates in South America back into close correspondence, but raises new questions about the timing and means of arrival of these two mammalian groups.

  16. Assessing the seismic risk potential of South America

    Science.gov (United States)

    Jaiswal, Kishor; Petersen, Mark D.; Harmsen, Stephen; Smoczyk, Gregory M.

    2016-01-01

    We present here a simplified approach to quantifying regional seismic risk. The seismic risk for a given region can be inferred in terms of average annual loss (AAL) that represents long-term value of earthquake losses in any one year caused from a long-term seismic hazard. The AAL are commonly measured in the form of earthquake shaking-induced deaths, direct economic impacts or indirect losses caused due to loss of functionality. In the context of South American subcontinent, the analysis makes use of readily available public data on seismicity, population exposure, and the hazard and vulnerability models for the region. The seismic hazard model was derived using available seismic catalogs, fault databases, and the hazard methodologies that are analogous to the U.S. Geological Survey’s national seismic hazard mapping process. The Prompt Assessment of Global Earthquakes for Response (PAGER) system’s direct empirical vulnerability functions in terms of fatality and economic impact were used for performing exposure and risk analyses. The broad findings presented and the risk maps produced herein are preliminary, yet they do offer important insights into the underlying zones of high and low seismic risks in the South American subcontinent. A more detailed analysis of risk may be warranted by engaging local experts, especially in some of the high risk zones identified through the present investigation.

  17. Connecting Realities: Peace Corps Volunteers in South America and the Global War on Poverty during the 1960s

    Directory of Open Access Journals (Sweden)

    Fernando Purcell

    2014-05-01

    Full Text Available This article examines the work of Peace Corps volunteers in South America during the 1960s. It argues that through their training in impoverished communities in the United States and their intervention in similar contexts in South America, these volunteers connected diverse visions of community action aimed at eradicating poverty. This allows an inclusion of a historical comprehension of the Peace Corps within the scenario of a Global War on Poverty. The argument derives from the analysis of letters and testimonies, press items, and official documents found in archives and libraries both in the United States and South America.

  18. Evolution of deepwater sedimentary environments and its implication for hydrocarbon exploration in Qiongdongnan Basin, northwestern South China Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenfeng; JIANG Tao; ZHANG Daojun; WANG Yahui; ZUO Qianmei; HE Weijun

    2015-01-01

    Over the past several years, a number of hydrocarbon reservoirs have been discovered in the deepwater area of Qiongdongnan Basin, northwestern South China Sea. These oil/gas fields demonstrate that the evolution of the deepwater sedimentary environment are controlling the formation and distribution of large-scale clastic reservoirs. Integration between seismic and borehole data were necessary to best clarify the distribution and quality of these deepwater reservoirs. Geochemical and paleobiological evidence from discrete samples was also applied to document specific information regarding the sedimentary environment. Results show that the Qiongdongnan Basin has existed as a thriving marine environment since Oligocene, when several rifting depressions developed throughout the entire Qiongdongnan Basin. Triggered by the faults activities, several distinct provenances supplied the coarse sediments, transporting and depositing them in deep parts of the rifting depressions. A fan delta system then formed nearby the source in the deeper area of these rifting depressions. The sedimentary environment of Qiongdongnan gradiationally became deepwater since early Miocene. Consequently, abundances of sediments were transported from Hainan Island and Southern Uplift, and then sunk into the basin center. The submarine fans revealed by many boreholes in this area verified them as good reservoir. Because the area reached its lowest sea level at late Miocene and the Southern Uplift subsidenced under sea level, not providing any sediment, so that the carbonate mesa and biorhythms characteristic of this area also developed during this period. In the west part of Qiongdongnan Basin, sediments transported from Vietnam increased in response to the Tibetan Uplift. Consequently, a central canyon developed along the center of Qiongdongnan Basin, which has been confirmed by several boreholes as a favorable hydrocarbon reservoir. The clarification of the deepwater sedimentary environment

  19. Biogeography of cedrela (meliaceae, sapindales) in central and South america.

    Science.gov (United States)

    Muellner, Alexandra N; Pennington, Terence D; Koecke, A Valerie; Renner, Susanne S

    2010-03-01

    Dated phylogenies have helped clarify the complex history of many plant families that today are restricted to the world's tropical forests, but that have Eocene, Oligocene, and Miocene fossils from the northern hemisphere. One such family is the Meliaceae. Here we infer the history of the neotropical Meliaceae genus Cedrela (17 species), the sister clade of which today is restricted to tropical Asia. Sequences from the nuclear ribosomal spacer region and five plastid loci obtained for all ingroup species and relevant outgroups were used to infer species relationships and for molecular-clock dating under two Bayesian relaxed clock models. The clock models differed in their handling of rate autocorrelation and sets of fossil constraints. Results suggest that (1) crown group diversification in Cedrela started in the Oligocene/Early Miocene and intensified in the Late Miocene and Early Pliocene, and (2) Central American Cedrela species do not form a clade, implying reentry into Central America after the closure of the Panamanian Isthmus. At present, Cedrela is distributed in both dry and humid habitats, but morphological features suggest an origin in dry forest under seasonal climates, fitting with Miocene and Pliocene Cedrela fossils from deciduous forests.

  20. Oroya fever and verruga peruana: bartonelloses unique to South America.

    Directory of Open Access Journals (Sweden)

    Michael F Minnick

    2014-07-01

    Full Text Available Bartonella bacilliformis is the bacterial agent of Carrión's disease and is presumed to be transmitted between humans by phlebotomine sand flies. Carrión's disease is endemic to high-altitude valleys of the South American Andes, and the first reported outbreak (1871 resulted in over 4,000 casualties. Since then, numerous outbreaks have been documented in endemic regions, and over the last two decades, outbreaks have occurred at atypical elevations, strongly suggesting that the area of endemicity is expanding. Approximately 1.7 million South Americans are estimated to be at risk in an area covering roughly 145,000 km2 of Ecuador, Colombia, and Peru. Although disease manifestations vary, two disparate syndromes can occur independently or sequentially. The first, Oroya fever, occurs approximately 60 days following the bite of an infected sand fly, in which infection of nearly all erythrocytes results in an acute hemolytic anemia with attendant symptoms of fever, jaundice, and myalgia. This phase of Carrión's disease often includes secondary infections and is fatal in up to 88% of patients without antimicrobial intervention. The second syndrome, referred to as verruga peruana, describes the endothelial cell-derived, blood-filled tumors that develop on the surface of the skin. Verrugae are rarely fatal, but can bleed and scar the patient. Moreover, these persistently infected humans provide a reservoir for infecting sand flies and thus maintaining B. bacilliformis in nature. Here, we discuss the current state of knowledge regarding this life-threatening, neglected bacterial pathogen and review its host-cell parasitism, molecular pathogenesis, phylogeny, sand fly vectors, diagnostics, and prospects for control.

  1. The research on typhoon wave spectrum in northwestern South China Sea

    Science.gov (United States)

    Shi, Hongyuan; Cao, Xuefeng; Wen, Xianhua; Shi, Maochong; Zhao, Dongliang; Guo, Peifang

    2017-02-01

    Based upon the one-year wind wave measurement data, collected from the South China Sea (SCS) at coordinates 20° 36.298'N, 110°45.433'E. by Acoustic Wave And Current (AWAC), we analyzed the wave characteristics and concluded that the most common wave direction was E and the second most common direction was ENE, the mean and the maximum values of significant height was 1.2 m and 4.36 m, respectively. The mean period was 4.0 s. We also evaluated the wave spectrums under conditions existing in three typhoons: Rumbi, Jeti and Utor. We found that unimodal spectrums occurred more often than others, and the maximum spectrum peak was 30.7911 m2 s. The minimum peak frequency was 0.0625 Hz, and the mean peak frequency was 0.126 Hz. The wave period is important for the design of marine structures, especially the position of peak frequency had a great influence on the stress calculation. Spectral analysis showed that the values of peak frequency distributed between 0.063 Hz and 0.217 Hz, with the mean value 0.114 Hz. We fit the normalized spectrum with 6 theoretical spectral models, out of which, the Wen spectrum, JONSWAP spectrum and Wallops spectrum were proved to give the best fit. What distinguished the Wen Spectrum from the rest was that it does not rely on the measured spectrum for parameter estimation. Hence, we recommend that the Wen spectrum should be widely used in marine construction.

  2. Predicting Fire Season Severity in South America Using Sea Surface Temperature Anomalies

    Science.gov (United States)

    Chen, Yang; Randerson, James T.; Morton, Douglas C.; Jin, Yufang; DeFries, Ruth S.; Collatz, George J.; Kasibhatla, Prasad S.; Giglio, Louis; Jin, Yufang; Marlier, Miriam

    2011-01-01

    Fires in South America cause forest degradation and contribute to carbon emissions associated with land use change. Here we investigated the relationship between year-to-year changes in satellite-derived estimates of fire activity in South America and sea surface temperature (SST) anomalies. We found that the Oceanic Ni o Index (ONI) was correlated with interannual fire activity in the eastern Amazon whereas the Atlantic Multidecadal Oscillation (AMO) index was more closely linked with fires in the southern and southwestern Amazon. Combining these two climate indices, we developed an empirical model that predicted regional annual fire season severity (FSS) with 3-5 month lead times. Our approach provides the foundation for an early warning system for forecasting the vulnerability of Amazon forests to fires, thus enabling more effective management with benefits for mitigation of greenhouse gas and air pollutant emissions.

  3. Forecasting Fire Season Severity in South America Using Sea Surface Temperature Anomalies

    Science.gov (United States)

    Chen, Yang; Randerson, James T.; Morton, Douglas C.; DeFries, Ruth S.; Collatz, G. James; Kasibhatla, Prasad S.; Giglio, Louis; Jin, Yufang; Marlier, Miriam E.

    2011-01-01

    Fires in South America cause forest degradation and contribute to carbon emissions associated with land use change. We investigated the relationship between year-to-year changes in fire activity in South America and sea surface temperatures. We found that the Oceanic Ni o Index was correlated with interannual fire activity in the eastern Amazon, whereas the Atlantic Multidecadal Oscillation index was more closely linked with fires in the southern and southwestern Amazon. Combining these two climate indices, we developed an empirical model to forecast regional fire season severity with lead times of 3 to 5 months. Our approach may contribute to the development of an early warning system for anticipating the vulnerability of Amazon forests to fires, thus enabling more effective management with benefits for climate and air quality.

  4. Forecasting Fire Season Severity in South America Using Sea Surface Temperature Anomalies

    Science.gov (United States)

    Chen, Yang; Randerson, James T.; Morton, Douglas C.; DeFries, Ruth S.; Collatz, G. James; Kasibhatla, Prasad S.; Giglio, Louis; Jin, Yufang; Marlier, Miriam E.

    2011-01-01

    Fires in South America cause forest degradation and contribute to carbon emissions associated with land use change. We investigated the relationship between year-to-year changes in fire activity in South America and sea surface temperatures. We found that the Oceanic Ni o Index was correlated with interannual fire activity in the eastern Amazon, whereas the Atlantic Multidecadal Oscillation index was more closely linked with fires in the southern and southwestern Amazon. Combining these two climate indices, we developed an empirical model to forecast regional fire season severity with lead times of 3 to 5 months. Our approach may contribute to the development of an early warning system for anticipating the vulnerability of Amazon forests to fires, thus enabling more effective management with benefits for climate and air quality.

  5. Mammals of South America, Volume 1, Marsupials, Xenarthrans, Shrews, and Bats

    Science.gov (United States)

    Gardner, A.L.

    2007-01-01

    The vast terrain between Panama and Tierra del Fuego contains some of the world?s richest mammalian fauna, but until now it has lacked a comprehensive systematic reference to the identification, distribution, and taxonomy of its mammals. The first such book of its kind and the inaugural volume in a three-part series, Mammals of South America both summarizes existing information and encourages further research of the mammals indigenous to the region. Containing identification keys and brief descriptions of each order, family, and genus, the first volume of Mammals of South America covers marsupials, shrews, armadillos, sloths, anteaters, and bats. Species accounts include taxonomic descriptions, synonymies, keys to identification, distributions with maps and a gazetteer of marginal localities, lists of recognized subspecies, brief summaries of natural history information, and discussions of issues related to taxonomic interpretations. Highly anticipated and much needed, this book will be a landmark contribution to mammalogy, zoology, tropical biology, and conservation biology.

  6. [Risk of transmission of cholera by fish products: regional perspective in South America].

    Science.gov (United States)

    Quevedo, F; Arámbulo, P; Escalante, J A; Estupiñán, J; Almeida, C; Cuellar, J

    1997-08-01

    Cholera returned to South America in January 1991, after almost a century of absence. The hygienic status of the countries affected, aggravated by economic and political difficulties, allowed the disease to spread rapidly. In Peru, fishery products were incriminated from the outset, although without conclusive evidence. However, epidemiological and laboratory findings in other countries have confirmed the transmission of the disease by these products. The authors discuss the effects of the recent cholera epidemic on the trade and consumption of fishery products in countries of South America. The actual risk of cholera transmission by food and in particular by the consumption of fishery products is discussed, and a basis for conducting an accurate evaluation of these risks is proposed. Finally, the authors summarise the measures recommended to prevent the transmission of cholera by fishery products.

  7. Identification of Potential Sites for Astronomical Observations in Northern South-America

    CERN Document Server

    Pinzón, G; Hernández, J

    2015-01-01

    In this study we describe an innovative method to determine potential sites for optical and infrared astronomical observations in the Andes region of northern South America. The method computes the Clear sky fraction (CSF) from Geostationary Observational Environmental Satellite (GOES) data for the years 2008-12 through a comparison with temperatures obtained from long-term records of weather stations and atmospheric temperature profiles from radiosonde. Criteria for sky clearance were established for two infrared GOES channels in order to determine potential sites in the Andes region of northern South-America. The method was validated using the reported observed hours at Observatorio Nacional de Llano del Hato in Venezuela. Separate CSF percentages were computed for dry and rainy seasons for both, photometric and spectroscopic night qualities. Twelve sites with five year averages of CSF for spectroscopic nights larger than 30% during the dry seasons were found to be suitable for astronomical observations. Th...

  8. The institutional foundations of energetic integration at the South America; Os fundamentos institucionais na integracao energetica da America do Sul

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, Lizett Paola Lopez; Guerra, Sinclair Mallet-Guy [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia]. E-mails: lizlosu@fem.unicamp.br, sguerra@fem.unicamp.br; Udaeta, Miguel Edgar Morales [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Eletrotecnica e Energia (IEE)]. E-mail: udaeta@pea.usp.br

    2006-07-01

    From the revision and analysis of the energy integration process in South America, the present article goals to show which are the institutional basis that endorse the process, once these entities act directly with questions related to the energy sector or to the wider economic integration where the energy integration is inserted. Thus, the Regional entities, that can be associations, organizations and commissions, like ALADI, ARPEL, CEPAL, CIER, OLADE and others are mentioned and analyzed. The analysis points out that these entities constitute the institutional basis for support the decision making of the region countries, considering the achieved studies, the promoted debates, the establishment of norms and information treatment. Finally, it is emphasized that these entities can not and should not have decide and execute, since are the governments (politic will) the responsible for the planning and coordination role for having the integration project effectively implemented. (author)

  9. Land use patterns and related carbon losses following deforestation in South America

    Science.gov (United States)

    De Sy, V.; Herold, M.; Achard, F.; Beuchle, R.; Clevers, J. G. P. W.; Lindquist, E.; Verchot, L.

    2015-12-01

    Land use change in South America, mainly deforestation, is a large source of anthropogenic CO2 emissions. Identifying and addressing the causes or drivers of anthropogenic forest change is considered crucial for global climate change mitigation. Few countries however, monitor deforestation drivers in a systematic manner. National-level quantitative spatially explicit information on drivers is often lacking. This study quantifies proximate drivers of deforestation and related carbon losses in South America based on remote sensing time series in a systematic, spatially explicit manner. Deforestation areas were derived from the 2010 global remote sensing survey of the Food and Agricultural Organisation Forest Resource Assessment. To assess proximate drivers, land use following deforestation was assigned by visual interpretation of high-resolution satellite imagery. To estimate gross carbon losses from deforestation, default Tier 1 biomass levels per country and eco-zone were used. Pasture was the dominant driver of forest area (71.2%) and related carbon loss (71.6%) in South America, followed by commercial cropland (14% and 12.1% respectively). Hotspots of deforestation due to pasture occurred in Northern Argentina, Western Paraguay, and along the arc of deforestation in Brazil where they gradually moved into higher biomass forests causing additional carbon losses. Deforestation driven by commercial cropland increased in time, with hotspots occurring in Brazil (Mato Grosso State), Northern Argentina, Eastern Paraguay and Central Bolivia. Infrastructure, such as urban expansion and roads, contributed little as proximate drivers of forest area loss (1.7%). Our findings contribute to the understanding of drivers of deforestation and related carbon losses in South America, and are comparable at the national, regional and continental level. In addition, they support the development of national REDD+ interventions and forest monitoring systems, and provide valuable input

  10. A Comparative Analysis of the Introduction of Travel Company In China and South America

    Institute of Scientific and Technical Information of China (English)

    彭红

    2013-01-01

      The introduction of Travel Company is a mirror which can display the culture of Travel Company and it is crucial when travelers make a choice. In order to make a better understanding of different introductions under different cultures, an analysis has been made between the introductions of two travel companies in China and South America respectively from the perspective of systemic-functional grammar(SFG).

  11. Prevalences, Genotypes, and Risk Factors for HIV Transmission in South America

    Science.gov (United States)

    2005-02-07

    Alava A, et al. HIV-1 genotype diversity in South America [abstract TuPeC4812]. In: Abstracts of the XIV Interna - tional AIDS Conference; 2002...University of Antioquia, Medellin, Colombia; Aracely Alava and Carlos Mosquera, Instituto Nacional de Higiene y Medicina Tropical ‘‘Leopoldo Izquieta Perez...Nacional de Enfermedades Tropicales (CENETROP), Santa Cruz, Bolivia; Adolfo H. Galeano, Instituto de Medicina Tropical (IMT), Asuncion, Paraguay; Jose C

  12. Annotated zoogeography of non-marine Tardigrada. Part II: South America.

    Science.gov (United States)

    Kaczmarek, Łukasz; Michalczyk, Łukasz; Mcinnes, Sandra J

    2015-02-25

    This paper is the second monograph of nine that describes the global records of limno-terrestrial water bears (Tardigrada). Here, we provide a comprehensive list of non-marine tardigrades recorded from South America, providing an updated and revised taxonomy accompanied by geographic co-ordinates, habitat, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographical and taxonomical studies.

  13. Arrival of Paleo-Indians to the southern cone of South America: new clues from mitogenomes.

    Directory of Open Access Journals (Sweden)

    Michelle de Saint Pierre

    Full Text Available With analyses of entire mitogenomes, studies of Native American mitochondrial DNA (MTDNA variation have entered the final phase of phylogenetic refinement: the dissection of the founding haplogroups into clades that arose in America during and after human arrival and spread. Ages and geographic distributions of these clades could provide novel clues on the colonization processes of the different regions of the double continent. As for the Southern Cone of South America, this approach has recently allowed the identification of two local clades (D1g and D1j whose age estimates agree with the dating of the earliest archaeological sites in South America, indicating that Paleo-Indians might have reached that region from Beringia in less than 2000 years. In this study, we sequenced 46 mitogenomes belonging to two additional clades, termed B2i2 (former B2l and C1b13, which were recently identified on the basis of mtDNA control-region data and whose geographical distributions appear to be restricted to Chile and Argentina. We confirm that their mutational motifs most likely arose in the Southern Cone region. However, the age estimate for B2i2 and C1b13 (11-13,000 years appears to be younger than those of other local clades. The difference could reflect the different evolutionary origins of the distinct South American-specific sub-haplogroups, with some being already present, at different times and locations, at the very front of the expansion wave in South America, and others originating later in situ, when the tribalization process had already begun. A delayed origin of a few thousand years in one of the locally derived populations, possibly in the central part of Chile, would have limited the geographical and ethnic diffusion of B2i2 and explain the present-day occurrence that appears to be mainly confined to the Tehuelche and Araucanian-speaking groups.

  14. Arrival of Paleo-Indians to the southern cone of South America: new clues from mitogenomes.

    Science.gov (United States)

    de Saint Pierre, Michelle; Gandini, Francesca; Perego, Ugo A; Bodner, Martin; Gómez-Carballa, Alberto; Corach, Daniel; Angerhofer, Norman; Woodward, Scott R; Semino, Ornella; Salas, Antonio; Parson, Walther; Moraga, Mauricio; Achilli, Alessandro; Torroni, Antonio; Olivieri, Anna

    2012-01-01

    With analyses of entire mitogenomes, studies of Native American mitochondrial DNA (MTDNA) variation have entered the final phase of phylogenetic refinement: the dissection of the founding haplogroups into clades that arose in America during and after human arrival and spread. Ages and geographic distributions of these clades could provide novel clues on the colonization processes of the different regions of the double continent. As for the Southern Cone of South America, this approach has recently allowed the identification of two local clades (D1g and D1j) whose age estimates agree with the dating of the earliest archaeological sites in South America, indicating that Paleo-Indians might have reached that region from Beringia in less than 2000 years. In this study, we sequenced 46 mitogenomes belonging to two additional clades, termed B2i2 (former B2l) and C1b13, which were recently identified on the basis of mtDNA control-region data and whose geographical distributions appear to be restricted to Chile and Argentina. We confirm that their mutational motifs most likely arose in the Southern Cone region. However, the age estimate for B2i2 and C1b13 (11-13,000 years) appears to be younger than those of other local clades. The difference could reflect the different evolutionary origins of the distinct South American-specific sub-haplogroups, with some being already present, at different times and locations, at the very front of the expansion wave in South America, and others originating later in situ, when the tribalization process had already begun. A delayed origin of a few thousand years in one of the locally derived populations, possibly in the central part of Chile, would have limited the geographical and ethnic diffusion of B2i2 and explain the present-day occurrence that appears to be mainly confined to the Tehuelche and Araucanian-speaking groups.

  15. Arrival of Paleo-Indians to the Southern Cone of South America: New Clues from Mitogenomes

    Science.gov (United States)

    de Saint Pierre, Michelle; Gandini, Francesca; Perego, Ugo A.; Bodner, Martin; Gómez-Carballa, Alberto; Corach, Daniel; Angerhofer, Norman; Woodward, Scott R.; Semino, Ornella; Salas, Antonio; Parson, Walther; Moraga, Mauricio; Achilli, Alessandro; Torroni, Antonio; Olivieri, Anna

    2012-01-01

    With analyses of entire mitogenomes, studies of Native American mitochondrial DNA (mtDNA) variation have entered the final phase of phylogenetic refinement: the dissection of the founding haplogroups into clades that arose in America during and after human arrival and spread. Ages and geographic distributions of these clades could provide novel clues on the colonization processes of the different regions of the double continent. As for the Southern Cone of South America, this approach has recently allowed the identification of two local clades (D1g and D1j) whose age estimates agree with the dating of the earliest archaeological sites in South America, indicating that Paleo-Indians might have reached that region from Beringia in less than 2000 years. In this study, we sequenced 46 mitogenomes belonging to two additional clades, termed B2i2 (former B2l) and C1b13, which were recently identified on the basis of mtDNA control-region data and whose geographical distributions appear to be restricted to Chile and Argentina. We confirm that their mutational motifs most likely arose in the Southern Cone region. However, the age estimate for B2i2 and C1b13 (11–13,000 years) appears to be younger than those of other local clades. The difference could reflect the different evolutionary origins of the distinct South American-specific sub-haplogroups, with some being already present, at different times and locations, at the very front of the expansion wave in South America, and others originating later in situ, when the tribalization process had already begun. A delayed origin of a few thousand years in one of the locally derived populations, possibly in the central part of Chile, would have limited the geographical and ethnic diffusion of B2i2 and explain the present-day occurrence that appears to be mainly confined to the Tehuelche and Araucanian-speaking groups. PMID:23240014

  16. Rapid coastal spread of First Americans: Novel insights from South America's Southern Cone mitochondrial genomes

    Science.gov (United States)

    Bodner, Martin; Perego, Ugo A.; Huber, Gabriela; Fendt, Liane; Röck, Alexander W.; Zimmermann, Bettina; Olivieri, Anna; Gómez-Carballa, Alberto; Lancioni, Hovirag; Angerhofer, Norman; Bobillo, Maria Cecilia; Corach, Daniel; Woodward, Scott R.; Salas, Antonio; Achilli, Alessandro; Torroni, Antonio; Bandelt, Hans-Jürgen; Parson, Walther

    2012-01-01

    It is now widely agreed that the Native American founders originated from a Beringian source population ∼15–18 thousand years ago (kya) and rapidly populated all of the New World, probably mainly following the Pacific coastal route. However, details about the migration into the Americas and the routes pursued on the continent still remain unresolved, despite numerous genetic, archaeological, and linguistic investigations. To examine the pioneering peopling phase of the South American continent, we screened literature and mtDNA databases and identified two novel mitochondrial DNA (mtDNA) clades, here named D1g and D1j, within the pan-American haplogroup D1. They both show overall rare occurrences but local high frequencies, and are essentially restricted to populations from the Southern Cone of South America (Chile and Argentina). We selected and completely sequenced 43 D1g and D1j mtDNA genomes applying highest quality standards. Molecular and phylogeographic analyses revealed extensive variation within each of the two clades and possibly distinct dispersal patterns. Their age estimates agree with the dating of the earliest archaeological sites in South America and indicate that the Paleo-Indian spread along the entire longitude of the American double continent might have taken even <2000 yr. This study confirms that major sampling and sequencing efforts are mandatory for uncovering all of the most basal variation in the Native American mtDNA haplogroups and for clarification of Paleo-Indian migrations, by targeting, if possible, both the general mixed population of national states and autochthonous Native American groups, especially in South America. PMID:22333566

  17. Socio-economic perspectives of family farming in south america: cases of bolivia, colombia and peru

    OpenAIRE

    2014-01-01

    Family farming is very important because it is, among other types, the principal source of food and employment, especially in developing countries. Given the constant changes in the agrarian structure and environment, what are the prospects of family farming under current conditions in South America? To answer this question, we have chosen three countries from this continent: Bolivia, Colombia, and Peru. Based on a literature review of case studies in each country, a comparative analysis of t...

  18. Lithium Geopolitics in South America and the divergents national public policies

    Directory of Open Access Journals (Sweden)

    Bernardo Salgado Rodrigues

    2016-12-01

    Full Text Available This article seeks to address the geopolitics of lithium in South America from the analysis of Argentine, Bolivian and Chilean public policies. Our hypothesis is that there is an institutional divergence between these countries with different projects related to this natural resource. From a geostrategic vision, we argued that regional integration can play a key role in the sovereignty of lithium for countries and their societies.

  19. Special challenges in the conservation of fishes and aquatic environments of South America.

    Science.gov (United States)

    Costa, M F; Barletta, M

    2016-07-01

    In South America, the conservation of natural resources, particularly in relation to water and aquatic fauna, is an often-discussed issue. Unfortunately, there is still a large gap between thoughts and action. Scientists from different countries of the continent have however, produced a significant body of literature that should finally become the basis of emerging managerial models. © 2016 The Fisheries Society of the British Isles.

  20. First report of Raoiella indica Hirst (Acari: Tenuipalpidae) in South America

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, Carlos [Universidad Centroccidental Lisandro Alvarado, Barquisimeto, Estado Lara (Venezuela, Bolivarian Republic of)]. E-mail: carlosvasquez@ucla.edu.ve; Quiros de G, Magally [Universidad del Zulia, Maracaibo, Estado Zulia, (Venezuela). Museo de Artropodos; Aponte, Orlando [Universidad Central de Venezuela, Estado Aragua (Venezuela). Inst. de Zoologia Agricola; Sandoval, D. Maria F. [Ministerio del Poder Popular para la Agricultura y Tierras (Venezuela). Servicio Autonomo de Sanidad Agropecuaria

    2008-11-15

    The presence of the red palm mite, Raoiella indica Hirst is recorded for the first time in South America. High populations and severe damages caused by this new invasive mite were found on coconut and banana leaves in Sucre (10 deg 27' 47{sup N} and 64 deg 10' 38{sup W}) and Monagas (9 deg 46'60{sup N} and 63 deg 12'0{sup W}) states in northeastern Venezuela. (author)

  1. Governance, agricultural intensification, and land sparing in tropical South America.

    Science.gov (United States)

    Ceddia, Michele Graziano; Bardsley, Nicholas Oliver; Gomez-y-Paloma, Sergio; Sedlacek, Sabine

    2014-05-20

    In this paper we address two topical questions: How do the quality of governance and agricultural intensification impact on spatial expansion of agriculture? Which aspects of governance are more likely to ensure that agricultural intensification allows sparing land for nature? Using data from the Food and Agriculture Organization, the World Bank, the World Database on Protected Areas, and the Yale Center for Environmental Law and Policy, we estimate a panel data model for six South American countries and quantify the effects of major determinants of agricultural land expansion, including various dimensions of governance, over the period 1970-2006. The results indicate that the effect of agricultural intensification on agricultural expansion is conditional on the quality and type of governance. When considering conventional aspects of governance, agricultural intensification leads to an expansion of agricultural area when governance scores are high. When looking specifically at environmental aspects of governance, intensification leads to a spatial contraction of agriculture when governance scores are high, signaling a sustainable intensification process.

  2. Using zircon U-Pb ages to constrain the provenance and transport of heavy minerals within the northwestern shelf of the South China Sea

    Science.gov (United States)

    Zhong, Lifeng; Li, Gang; Yan, Wen; Xia, Bin; Feng, Yuexing; Miao, Li; Zhao, Jianxin

    2017-02-01

    Numerous ore-grade heavy mineral placer deposits occur in the northern South China Sea region. Previous studies on these deposits have focused on the heavy-mineral ore resources themselves, but the provenance and transport pathways of these heavy minerals are poorly constrained. This paper presents U-Pb ages of detrital zircons from sediments within the northwestern shelf of the South China Sea, and uses this new dataset to determine the provenance and transport pathway of the sediments. Zircons in sediments from ten areas of the northwestern shelf exhibit distinct age populations, suggesting that they have multiple provenances. Zircons in sediments from the Pearl River Mouth, Shangchuan Island, and Moyang River Mouth areas all have an obvious peak of Mesozoic ages, indicating that they have similar sediment provenances; i.e., mainly from the Pearl River, and to a lesser degree from the Moyang River. Zircons in sediments from the areas around the Jian River Mouth and Leizhou Bay, and off Hainan Island have an early Paleozoic age, suggesting that the sediments predominantly originate from the Yunkai massif. Zircons of the sediments from the remaining four areas, the Leiqiong Strait, Wanquan River Mouth, Qiongdongnan, and the Outer Shelf, have Yanshannian and Indosinian age peaks in addition to an obvious early Paleozoic population, implying mixed provenances, including the Yunkai massif and Hainan Island. The sediment transport may have involved two hydrodynamic conditions in two distinct stages. First, the Guangdong Longshore Current carried the river sediments to where they dispersed in the inner shelf; subsequently, wave-induced strong currents further transported sandy sediments southeastward to the outer shelf. In addition to explaining the provenance and transport pathways of heavy minerals within the northwestern shelf of the South China Sea, these results provide new information relevant to exploration for heavy-mineral placer deposits.

  3. Potential geographical distribution of the red palm mite in South America.

    Science.gov (United States)

    Amaro, George; de Morais, Elisangela Gomes Fidelis

    2013-07-01

    Among pests that have recently been introduced into the Americas, the red palm mite, Raoiella indica Hirst (Prostigmata: Tenuipalpidae), is the most invasive. This mite has spread rapidly to several Caribbean countries, United States of America, Mexico, Venezuela, Colombia and Brazil. The potential dispersion of R. indica to other regions of South America could seriously impact the cultivation of coconuts, bananas, exotic and native palms and tropical flowers such as the Heliconiaceae. To facilitate the development of efficacious R. indica management techniques such as the adoption of phytosanitary measures to prevent or delay the dispersion of this pest, the objective of this paper was to estimate the potential geographical distribution of R. indica in South America using a maximum entropy model. The R. indica occurrence data used in this model were obtained from extant literature, online databases and field sampling data. The model predicted potential suitable areas for R. indica in northern Colombia, central and northern Venezuela, Guyana, Suriname, east French Guiana and many parts of Brazil, including Roraima, the eastern Amazonas, northern Pará, Amapá and the coastal zones, from Pará to north of Rio de Janeiro. These results indicate the potential for significant R. indica related economic and social impacts in all of these countries, particularly in Brazil, because the suitable habitat regions overlap with agricultural areas for R. indica host plants such as coconuts and bananas.

  4. South America electric power integration: an utopia or a reality?; Integracao eletrica sul-americana: utopia ou realidade?

    Energy Technology Data Exchange (ETDEWEB)

    Velez, Jaime

    2007-07-01

    The aim of this chapter is the discussing on the economic and institutional conditions necessary to the South America electric power integration in the context of the changes in the electric industry initiated on the 1980's years.

  5. Strong plate coupling along the Nazca-South America convergent margin

    Science.gov (United States)

    Iaffaldano, Giampiero; Bunge, Hans-Peter

    2008-06-01

    The force balance in plate tectonics is fundamentally importantbut poorly known. Here, we show that two prominent and seeminglyunrelated observations—trench-parallel gravity anomaliesalong the Nazca-South America margin that coincide withthe rupture zones of great earthquakes, and a rapid slowdownof Nazca-South America convergence over the past 10 m.y.—providekey insights. Both result from rapid Miocene-Pliocene upliftof the Andes and provide quantitative measures of the magnitudeand distribution of plate coupling along the Nazca-SouthAmerica margin. We compute the plate-tectonic force budget usingglobal models of the faulted lithosphere coupled to high-resolutionmantle circulation models and find that Andean-related plate-marginforces are comparable to plate-driving forces from the mantle,and they have sufficient magnitude to account for pronouncedbathymetry variations along the trench. Our results suggestthat plate coupling, gravity anomalies, and bathymetry variationsalong a given trench are all controlled by long-term stressvariations in the upper portion of plate boundaries and thatan explicit budget of driving and resisting forces in platetectonics can be obtained. For the convergent margin consideredhere, spatial variations in the effective coefficient of frictionassociated with the distribution of lubricating sediments enteringthe trench are, by comparison, of minor importance.

  6. Predicting geographic distributions of Phacellodomus species (Aves: Furnariidae in South America based on ecological niche modeling

    Directory of Open Access Journals (Sweden)

    Maria da Salete Gurgel Costa

    2014-08-01

    Full Text Available Phacellodomus Reichenbach, 1853, comprises nine species of Furnariids that occur in South America in open and generally dry areas. This study estimated the geographic distributions of Phacellodomus species in South America by ecological niche modeling. Applying maximum entropy method, models were produced for eight species based on six climatic variables and 949 occurrence records. Since highest climatic suitability for Phacellodomus species has been estimated in open and dry areas, the Amazon rainforest areas are not very suitable for these species. Annual precipitation and minimum temperature of the coldest month are the variables that most influence the models. Phacellodomus species occurred in 35 ecoregions of South America. Chaco and Uruguayan savannas were the ecoregions with the highest number of species. Despite the overall connection of Phacellodomus species with dry areas, species such as P. ruber, P. rufifrons, P. ferrugineigula and P. erythrophthalmus occurred in wet forests and wetland ecoregions.

  7. The children of mama coca: coca, cocaine and the fate of harm reduction in South America.

    Science.gov (United States)

    Bastos, Francisco I; Caiaffa, Waleska; Rossi, Diana; Vila, Marcelo; Malta, Monica

    2007-03-01

    The paper reviews the main findings from substance misuse research carried out over the last two decades in South America looking at the main initiatives aimed at reducing drug related harm and curbing the spread of HIV/AIDS and other sexually transmitted and blood-borne diseases. The current challenges faced by harm reduction in the region are analysed from the perspective of the history of coca and its different uses in South America. Except in Brazil and Argentina, the implementation of initiatives to reduce drug related harm in South America has been very cautious. The paper aims to link the analysis of harms associated with the use of illicit substances, with the often paradoxically harmful effects of supply-side drug policies in the world's largest coca/cocaine producing area. Despite the undeniable success of many initiatives, the broader context of harm maximization through structural violence and entrenched corruption acts as a major disincentive for the comprehensive adoption of sound public health policies.

  8. Monitoring the Quality of Medicines: Results from Africa, Asia, and South America

    Science.gov (United States)

    Hajjou, Mustapha; Krech, Laura; Lane-Barlow, Christi; Roth, Lukas; Pribluda, Victor S.; Phanouvong, Souly; El-Hadri, Latifa; Evans, Lawrence; Raymond, Christopher; Yuan, Elaine; Siv, Lang; Vuong, Tuan-Anh; Boateng, Kwasi Poku; Okafor, Regina; Chibwe, Kennedy M.; Lukulay, Patrick H.

    2015-01-01

    Monitoring the quality of medicines plays a crucial role in an integrated medicines quality assurance system. In a publicly available medicines quality database (MQDB), the U.S. Pharmacopeial Convention (USP) reports results of data collected from medicines quality monitoring (MQM) activities spanning the period of 2003–2013 in 17 countries of Africa, Asia, and South America. The MQDB contains information on 15,063 samples collected and tested using Minilab® screening methods and/or pharmacopeial methods. Approximately 71% of the samples reported came from Asia, 23% from Africa, and 6% from South America. The samples collected and tested include mainly antibiotic, antimalarial, and antituberculosis medicines. A total of 848 samples, representing 5.6% of total samples, failed the quality test. The failure proportion per region was 11.5%, 10.4%, and 2.9% for South America, Africa, and Asia, respectively. Eighty-one counterfeit medicines were reported, 86.4% of which were found in Asia and 13.6% in Africa. Additional analysis of the data shows the distribution of poor-quality medicines per region and by therapeutic indication as well as possible trends of counterfeit medicines. PMID:25897073

  9. Energy reforms of the natural gas industry in South America; Reformas energeticas da industria do gas natural na America do Sul

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales Palomino, Raul; Nebra de Perez, Silvia Azucena; Bajay, Sergio Valdir [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica]. E-mails: rgpuni@fem.unicamp.br; sanebra@fem.unicamp.br; bajay@fem.unicamp.br; Galarza Soto, Walter [Universidad Nacional de Ingenieria (UNI), Lima (Peru).Facultad de Ingenieria Mecanica]. E-mail: w_galarza@uni.edu.pe

    2004-07-01

    This paper analyzes the reforms in the natural gas policies, its regulation and integration in South America. Studying the main legislative reforms in the gas sector of the Argentina, Bolivia, Brazil, Chile, Colombia, Peru and Venezuela. Finally, we sketched a map of South America with the pipeline of regional integration. The reforms have resulted in the liberalization of markets, elimination of state monopolies, the promotion of private investment and the reduction of the State business activity. The market failures, such as natural monopoly and asymmetric information, result of the regulatory bodies creation. The promotion of actions to reduce risks and facilitate the entry of new investments, the strengthening of competition, and the ability of regulatory agencies are important guidelines for the integration natural gas in South America.

  10. Widespread occurrence of bd in French Guiana, South America.

    Science.gov (United States)

    Courtois, Elodie A; Gaucher, Philippe; Chave, Jérôme; Schmeller, Dirk S

    2015-01-01

    The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) is a purported agent of decline and extinction of many amphibian populations worldwide. Its occurrence remains poorly documented in many tropical regions, including the Guiana Shield, despite the area's high amphibian diversity. We conducted a comprehensive assessment of Bd in French Guiana in order to (1) determine its geographical distribution, (2) test variation of Bd prevalence among species in French Guiana and compare it to earlier reported values in other South American anuran species (http://www.bd-maps.net; 123 species from 15 genera) to define sentinel species for future work, (3) track changes in prevalence through time and (4) determine if Bd presence had a negative effect on one selected species. We tested the presence of Bd in 14 species at 11 sites for a total of 1053 samples (306 in 2009 and 747 in 2012). At least one Bd-positive individual was found at eight out of 11 sites, suggesting a wide distribution of Bd in French Guiana. The pathogen was not uniformly distributed among the studied amphibian hosts, with Dendrobatidae species displaying the highest prevalence (12.4%) as compared to Bufonidae (2.6 %) and Hylidae (1.5%). In contrast to earlier reported values, we found highest prevalence for three Dendrobatidae species and two of them displayed an increase in Bd prevalence from 2009 to 2012. Those three species might be the sentinel species of choice for French Guiana. For Dendrobates tinctorius, of key conservation value in the Guiana Shield, smaller female individuals were more likely to be infected, suggesting either that frogs can outgrow their chytrid infections or that the disease induces developmental stress limiting growth. Generally, our study supports the idea that Bd is more widespread than previously thought and occurs at remote places in the lowland forest of the Guiana shield.

  11. Widespread occurrence of bd in French Guiana, South America.

    Directory of Open Access Journals (Sweden)

    Elodie A Courtois

    Full Text Available The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd is a purported agent of decline and extinction of many amphibian populations worldwide. Its occurrence remains poorly documented in many tropical regions, including the Guiana Shield, despite the area's high amphibian diversity. We conducted a comprehensive assessment of Bd in French Guiana in order to (1 determine its geographical distribution, (2 test variation of Bd prevalence among species in French Guiana and compare it to earlier reported values in other South American anuran species (http://www.bd-maps.net; 123 species from 15 genera to define sentinel species for future work, (3 track changes in prevalence through time and (4 determine if Bd presence had a negative effect on one selected species. We tested the presence of Bd in 14 species at 11 sites for a total of 1053 samples (306 in 2009 and 747 in 2012. At least one Bd-positive individual was found at eight out of 11 sites, suggesting a wide distribution of Bd in French Guiana. The pathogen was not uniformly distributed among the studied amphibian hosts, with Dendrobatidae species displaying the highest prevalence (12.4% as compared to Bufonidae (2.6 % and Hylidae (1.5%. In contrast to earlier reported values, we found highest prevalence for three Dendrobatidae species and two of them displayed an increase in Bd prevalence from 2009 to 2012. Those three species might be the sentinel species of choice for French Guiana. For Dendrobates tinctorius, of key conservation value in the Guiana Shield, smaller female individuals were more likely to be infected, suggesting either that frogs can outgrow their chytrid infections or that the disease induces developmental stress limiting growth. Generally, our study supports the idea that Bd is more widespread than previously thought and occurs at remote places in the lowland forest of the Guiana shield.

  12. Neotropical mammal diversity and the Great American Biotic Interchange: spatial and temporal variation in South America's fossil record

    OpenAIRE

    Juan David Carrillo; Analía eForasiepi; Carlos eJaramillo; Marcelo R. eSánchez-Villagra

    2015-01-01

    The vast mammal diversity of the Neotropics is the result of a long evolutionary history. During most of the Cenozoic, South America was an island continent with an endemic mammalian fauna. This isolation ceased during the late Neogene after the formation of the Isthmus of Panama, resulting in an event known as the Great American Biotic Interchange (GABI). In this study, we investigate biogeographic patterns in South America, just before or when the first immigrants are recorded and we review...

  13. Methodology of Leaving America for Asia: Reading South Korea's Social Studies Textbooks through Chen Kuan-Hsing's Asia as Method

    Science.gov (United States)

    Rhee, Jeong-eun

    2013-01-01

    This project began as a content analysis of five South Korean high school Social Studies textbooks. Yet, it has evolved into an epistemological experiment to pursue the question of "what does it mean to leave America for Asia, at least methodologically, for the researcher who left Asia for America?" Using the textbooks as a mediating…

  14. Low-carbon agriculture in South America to mitigate global climate change and advance food security.

    Science.gov (United States)

    Sá, João Carlos de Moraes; Lal, Rattan; Cerri, Carlos Clemente; Lorenz, Klaus; Hungria, Mariangela; de Faccio Carvalho, Paulo Cesar

    2017-01-01

    The worldwide historical carbon (C) losses due to Land Use and Land-Use Change between 1870 and 2014 are estimated at 148 Pg C (1 Pg=1billionton). South America is chosen for this study because its soils contain 10.3% (160 Pg C to 1-m depth) of the soil organic carbon stock of the world soils, it is home to 5.7% (0.419 billion people) of the world population, and accounts for 8.6% of the world food (491milliontons) and 21.0% of meat production (355milliontons of cattle and buffalo). The annual C emissions from fossil fuel combustion and cement production in South America represent only 2.5% (0.25 Pg C) of the total global emissions (9.8 Pg C). However, South America contributes 31.3% (0.34 Pg C) of global annual greenhouse gas emissions (1.1 Pg C) through Land Use and Land Use Change. The potential of South America as a terrestrial C sink for mitigating climate change with adoption of Low-Carbon Agriculture (LCA) strategies based on scenario analysis method is 8.24 Pg C between 2016 and 2050. The annual C offset for 2016 to 2020, 2021 to 2035, and 2036 to 2050 is estimated at 0.08, 0.25, and 0.28 Pg C, respectively, equivalent to offsetting 7.5, 22.2 and 25.2% of the global annual greenhouse gas emissions by Land Use and Land Use Change for each period. Emission offset for LCA activities is estimated at 31.0% by restoration of degraded pasturelands, 25.6% by integrated crop-livestock-forestry-systems, 24.3% by no-till cropping systems, 12.8% by planted commercial forest and forestation, 4.2% by biological N fixation and 2.0% by recycling the industrial organic wastes. The ecosystem carbon payback time for historical C losses from South America through LCA strategies may be 56 to 188years, and the adoption of LCA can also increase food and meat production by 615Mton or 17.6Mtonyear(-1) and 56Mton or 1.6Mtonyear(-1), respectively, between 2016 and 2050.

  15. Moisture transport and intraseasonal variability in the South America monsoon system

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Leila M.V. [University of California Santa Barbara, Department of Geography, Santa Barbara, CA (United States); University of Sao Paulo, Department of Atmospheric Sciences, Sao Paulo (Brazil); University of California Santa Barbara, Institute for Computational Earth System Sciences, Santa Barbara, CA (United States); Silva, Ana E.; Rocha, Humberto R. [University of Sao Paulo, Department of Atmospheric Sciences, Sao Paulo (Brazil); Jones, Charles [University of California Santa Barbara, Institute for Computational Earth System Sciences, Santa Barbara, CA (United States); Liebmann, Brant [CIRES Climate Diagnostics Center, Boulder, CO (United States); Silva Dias, Pedro L. [University of Sao Paulo, Department of Atmospheric Sciences, Sao Paulo (Brazil); National Laboratory for Scientific Computing, Petropolis (Brazil)

    2011-05-15

    This paper examines moisture transport on intraseasonal timescales over the continent and over the South Atlantic convergence zone (SACZ) during the South America (SA) summer monsoon. Combined Empirical Orthogonal Function analysis (EOFc) of Global Precipitation Climatology Project pentad precipitation, specific humidity, air temperature, zonal and meridional winds at 850 hPa (NCEP/NCAR reanalysis) are performed to identify the large-scale variability of the South America monsoon system and the SACZ. The first EOFc was used as a large-scale index for the South American monsoon (LISAM), whereas the second EOFc characterized the SACZ. LISAM (SACZ) index showed spectral variance on 30-90 (15-20) days and were both band filtered (10-100 days). Intraseasonal wet anomalies were defined when LISAM and SACZ anomalies were above the 75th percentile of their respective distribution. LISAM and SACZ wet events were examined independently of each other and when they occur simultaneously. LISAM wet events were observed with the amplification of wave activity in the Northern Hemisphere and the enhancement of northwesterly cross-equatorial moisture transport over tropical continental SA. Enhanced SACZ was observed with moisture transport from the extratropics of the Southern Hemisphere. Simultaneous LISAM and SACZ wet events are associated with cross-equatorial moisture transport along with moisture transport from Subtropical Southwestern Atlantic. (orig.)

  16. Brazil and regional integration in South America: lessons from the EU's crisis

    Directory of Open Access Journals (Sweden)

    Elena Lazarou

    2013-12-01

    Full Text Available This paper introduces the idea of the EU as a 'model' of regional integration, linking it to the literature on Europe as a normative power. The second part discusses the influence of the EU model on regional cooperation and integration in South America. In particular, it focuses on the discursive use of the model in Brazilian foreign policy during the two tenures of President Luis Inacio Lula da Silva as a dominant rhetoric for the promotion of regional integration, especially in the case of the Mercado Común del Sur(Common Market of the South, MERCOSUR and the Unión de Naciones Suramericanas (Union of South American Nations, UNASUR. The last part looks at the impact of the financial crisis on the 'deconstruction' of this ideal model of European integration and attempts to discern how this will influence the future discourse on regional cooperation integration in South America, and primarily in Brazil. To illustrate the shift that has occurred in Brazilian views of regionalism, this part also discusses the Brazilian support of a new form of regional integration, as embodied in the creation of CELAC, the Community of Latin American and Caribbean States.

  17. Brazilian foreign affairs: social capital and the democratic discourse in South America

    Directory of Open Access Journals (Sweden)

    Rafael Duarte Villa

    2007-01-01

    Full Text Available Brazilian elites as well as foreign policy-makers have long shared a common belief that the ideas of democracy and democratization should serve as some "road map" to foreign policy-making. In areas such as security, regional integration, and disarmament, the goal has been to generate a positive social capital as well as to build trusting relations with Brazilian neighbors in South America. Therefore, under the impact of ideas brought about by new world visions, Brazilian foreign policy has changed a domestic policy feature - the democratic rearrangement of the political system - into a condition and resource for foreign policy-making towards South America. The result has been a fine improvement of Brazilian image and credibility in the regional South American scenario. In other words, there has been a significant increment in "trust" towards Brazil. This argument has been developed based on extracts and transcripts from official diplomatic speeches from Brazilian foreign policy-makers as well as a historical reconstruction of Brazil's diplomatic relations with two South American countries. Our study was based on two cases: Brazilian-Venezuelan and Brazilian-Argentine relations in the 80's and the 90's.

  18. Hydrogeologic framework and groundwater/surface-water interactions of the South Fork Nooksack River Basin, northwestern Washington

    Science.gov (United States)

    Gendaszek, Andrew S.

    2014-01-01

    A hydrogeologic framework of the South Fork (SF) Nooksack River Basin in northwestern Washington was developed and hydrologic data were collected to characterize the groundwater-flow system and its interaction with surface‑water features. In addition to domestic, agricultural, and commercial uses of groundwater within the SF Nooksack River Basin, groundwater has the potential to provide ecological benefits by maintaining late-summer streamflows and buffering stream temperatures. Cold-water refugia, created and maintained in part by groundwater, have been identified by water-resource managers as key elements to restore the health and viability of threatened salmonids in the SF Nooksack River. The SF Nooksack River drains a 183-square mile area of the North Cascades and the Puget Lowland underlain by unconsolidated glacial and alluvial sediments deposited over older sedimentary, metamorphic, and igneous bedrock. The primary aquifer that interacts with the SF Nooksack River was mapped within unconsolidated glacial outwash and alluvial sediment. The lower extent of this unit is bounded by bedrock and fine-grained, poorly sorted unconsolidated glaciomarine and glaciolacustrine sediments. In places, these deposits overlie and confine an aquifer within older glacial sediments. The extent and thickness of the hydrogeologic units were assembled from mapped geologic units and lithostratigraphic logs of field-inventoried wells. Generalized groundwater-flow directions within the surficial aquifer were interpreted from groundwater levels measured in August 2012; and groundwater seepage gains and losses to the SF Nooksack River were calculated from synoptic streamflow measurements made in the SF Nooksack River and its tributaries in September 2012. A subset of the field-inventoried wells was measured at a monthly interval to determine seasonal fluctuations in groundwater levels during water year 2013. Taken together, these data provide the foundation for a future groundwater

  19. [Regional cooperation and integration in health in South America: the contribution of Unasur-Health].

    Science.gov (United States)

    Buss, Paulo Marchiori; Ferreira, José Roberto

    2011-06-01

    The scope of this study is to discuss the process of integration of South America in the domain of health, from the constitution of the Union of South American Nations (Unasur), in May 2008, through to the emergence of the Unasur Council of Health, in 2009, and its ongoing development in the past year (2009-2010). This study is descriptive in nature and the medium of investigation was the case study. The authors present the main constituent elements of the South-American Health Agenda, with particular emphasis on the area of development and management of human resources in health, which was coordinated by Brazil in the past year. The authors conclude that this interchange will contribute to minimization of the asymmetries amongst the countries, collaborating to improve the quality of life and health conditions in the region.

  20. Transboundary conservation: An ecoregional approach to protect neotropical migratory birds in South America

    Science.gov (United States)

    Roca, Roberto; Adkins, Leslie; Wurschy, Maria Christina; Skerl, Kevin

    1996-11-01

    Future conservation efforts will need to transcend geopolitical boundaries in efforts to protect entire landscapes and ecosystems. Neotropical migratory birds are as a group a useful conservation tool for linking diverse landscapes and people due to their dependence on multiple habitats, sensitivity to habitat changes, and universal public appeal. The conservation of neotropical migrants can therefore function as a powerful hemispheric umbrella for ecosystem protection. Efforts to protect neotropical migratory birds on their nonbreeding grounds have traditionally been focused on Mexico, Central America, and the Caribbean. To assess the importance of South America to neotropical migrants, an ecoregional classification system was used to determine species distributions in the Andean/Southern Cone Region (Bolivia, Colombia, Ecuador, Paraguay, Peru, and Venezuela). The occurrence of migrants in protected areas that are part of The Nature Conservancy's Parks in Peril program was also assessed. Of the 406 neotropical migrant species, nearly one third (132) occur as regular nonbreeding residents in the region and for almost half of these species (53), South America is their main nonbreeding ground. All Parks in Peril sites were found to harbor neotropical migrants. Forty-eight species (36%) have declining longterm North American Breeding Bird Survey population trends and/or high Partners in Flight concern scores and thus are of significant conservation concern. Most importantly, 29 species (22%) of conservation concern use South America as their primary nonbreeding ground, indicating a need for focused conservation action. The nature of the ecoregional approach used in this endeavor makes future prioritization of ecoregions and conservation strategies for neotropical migrants across national boundaries possible. The ability to link diverse landscapes using a common element such as migratory birds allows for unique transboundary partnerships and opportunities for habitat

  1. North-South precipitation patterns in western North America on interannual-to-decadal timescales

    Science.gov (United States)

    Dettinger, M.D.; Cayan, D.R.; Diaz, Henry F.; Meko, D.M.

    1998-01-01

    The overall amount of precipitation deposited along the West Coast and western cordillera of North America from 25??to 55??N varies from year to year, and superimposed on this domain-average variability are varying north-south contrasts on timescales from at least interannual to interdecadal. In order to better understand the north-south precipitation contrasts, their interannual and decadal variations are studied in terms of how much they affect overall precipitation amounts and how they are related to large-scale climatic patterns. Spatial empirical orthogonal functions (EOFs) and spatial moments (domain average, central latitude, and latitudinal spread) of zonally averaged precipitation anomalies along the westernmost parts of North America are analyzed, and each is correlated with global sea level pressure (SLP) and sea surface temperature series, on interannual (defined here as 3-7 yr) and decadal (>7 yr) timescales. The interannual band considered here corresponds to timescales that are particularly strong in tropical climate variations and thus is expected to contain much precipitation variability that is related to El Nino-Southern Oscillation; the decadal scale is defined so as to capture the whole range of long-term climatic variations affecting western North America. Zonal EOFs of the interannual and decadal filtered versions of the zonal-precipitation series are remarkably similar. At both timescales, two leading EOFs describe 1) a north-south seesaw of precipitation pivoting near 40??N and 2) variations in precipitation near 40??N, respectively. The amount of overall precipitation variability is only about 10% of the mean and is largely determined by precipitation variations around 40??-45??N and most consistently influenced by nearby circulation patterns; in this sense, domain-average precipitation is closely related to the second EOF. The central latitude and latitudinal spread of precipitation distributions are strongly influenced by precipitation

  2. Dispersal of Pleistocene Equus (Family Equidae) into South America and calibration of GABI 3 based on evidence from Tarija, Bolivia.

    Science.gov (United States)

    MacFadden, Bruce J

    2013-01-01

    The dispersal of Equus into South America during the Great American Biotic Interchange (GABI) represented a major event for Pleistocene land-mammal age chronology on that continent. It has been argued that this dispersal occurred during the late Pleistocene, ∼0.125 Ma, and it defines the base of the Lujanian South American Land Mammal Age (SALMA). In this scenario, Equus dispersed during the fourth and latest recognized phase of the interchange, i.e., GABI 4. Although Equus was widely distributed in South America during the Pleistocene, only a few localities are calibrated by independent chronostratigraphic data. In this paper, new biostratigraphic evidence documents that Equus occurs from 15 superposed faunal horizons or zones throughout the Tolomosa Formation at Tarija, Bolivia. This biostratigraphic sequence is independently calibrated to occur between ∼0.99 to <0.76 Ma during the middle Pleistocene Ensenadan SALMA and coincident with GABI 3, not GABI 4. Tarija remains the only well calibrated Ensenadan locality at which Equus is found. The new biostratigraphic data presented here are unambiguous and document the earlier (pre-Lujanian) occurrence of this genus in South America. The hypothesized dispersal of the genus Equus into South America at ∼0.125 Ma is no longer supportable in light of the new biostratigraphic evidence presented here. The new data from Tarija thus have continent-wide implications for the origins and biogeography of Equus in South America as well as the calibration of GABI 3.

  3. Dispersal of Pleistocene Equus (Family Equidae into South America and calibration of GABI 3 based on evidence from Tarija, Bolivia.

    Directory of Open Access Journals (Sweden)

    Bruce J MacFadden

    Full Text Available The dispersal of Equus into South America during the Great American Biotic Interchange (GABI represented a major event for Pleistocene land-mammal age chronology on that continent. It has been argued that this dispersal occurred during the late Pleistocene, ∼0.125 Ma, and it defines the base of the Lujanian South American Land Mammal Age (SALMA. In this scenario, Equus dispersed during the fourth and latest recognized phase of the interchange, i.e., GABI 4. Although Equus was widely distributed in South America during the Pleistocene, only a few localities are calibrated by independent chronostratigraphic data. In this paper, new biostratigraphic evidence documents that Equus occurs from 15 superposed faunal horizons or zones throughout the Tolomosa Formation at Tarija, Bolivia. This biostratigraphic sequence is independently calibrated to occur between ∼0.99 to <0.76 Ma during the middle Pleistocene Ensenadan SALMA and coincident with GABI 3, not GABI 4. Tarija remains the only well calibrated Ensenadan locality at which Equus is found. The new biostratigraphic data presented here are unambiguous and document the earlier (pre-Lujanian occurrence of this genus in South America. The hypothesized dispersal of the genus Equus into South America at ∼0.125 Ma is no longer supportable in light of the new biostratigraphic evidence presented here. The new data from Tarija thus have continent-wide implications for the origins and biogeography of Equus in South America as well as the calibration of GABI 3.

  4. Transition from the Farallon Plate subduction to the collision between South and Central America: Geological evolution of the Panama Isthmus

    Science.gov (United States)

    Barat, Flore; Mercier de Lépinay, Bernard; Sosson, Marc; Müller, Carla; Baumgartner, Peter O.; Baumgartner-Mora, Claudia

    2014-05-01

    This paper presents new geological constraints on the collision of southern Central America with South America, and the resulting deformational episodes that have affected the Panama Isthmus since the Late Cretaceous. The Panama Isthmus is located in southwestern Central America, and it represents the zone of contact between the two land masses: Central America and South America. This collision event is still active today. It has resulted in regional uplift since the Late Miocene/Pliocene and is responsible for the Great American Biotic Interchange between South and North America. Depending on the methods of investigation used, and due to the lack of data available, the time when this collision began is still widely debated and poorly constrained. To better constrain this age, we have studied the rock formations and the tectonic deformations in central and eastern Panama that have occurred since the Late Cretaceous. This study presents new rock ages, field-work documentation and analyses, and seismic-line interpretations, and it is complemented by spatial images for the eastern Panama area. During the Middle Eocene, a number of changes suddenly appeared in the geological records that were synchronous with the break-up of southern Central America into two smaller blocks: Chorotega and Chocó. Our main results identify the prevalence of an extensional tectonic regime from the Middle Eocene to the Middle Miocene that caused the formation of horst and graben structures with thick sedimentary basin fills, and a synchronous clockwise block rotation. Here, we propose that these geologic events are associated with the initiation of the oblique collision of southern Central America with South America. The first contact of the southeastern extremity of Central America occurred around 40 Ma to 38 Ma, and then propagated northwestwards. We describe here this long-term collision episode in relation to the history of the Panama Isthmus.

  5. Delivery scheduling centralization for industrial and medical gases in South America; Centralizacao do planejamento de entregas para gases industriais e medicinais - America do Sul

    Energy Technology Data Exchange (ETDEWEB)

    Cicotti, Bruno [America do Sul Linde Gases (Brazil)

    2010-07-01

    Aligned with the Linde's vision for the future that is searching for high performance in its process and the excellence in the services supplied to the customers, the Bulk Logistic Department of South America developed and implemented a project of scheduling centralization of bulk gases, embracing ten countries in the region. (author)

  6. On Vastness and Variability: Cultural Transmission, Historicity, and the Paleoindian Record in Eastern South America

    Directory of Open Access Journals (Sweden)

    ASTOLFO G.M. ARAUJO

    2015-06-01

    Full Text Available Eastern South America, or what is today Brazilian territory, poses interesting questions about the early human occupation of the Americas. Three totally distinct and contemporaneous lithic technologies, dated between 11,000 and 10,000 14C BP, are present in different portions of the country: the Umbu tradition in the south, with its formal bifacial industry, with well-retouched scrapers and bifacial points; the Itaparica tradition in the central-west / northwest, totally unifacial, whose only formal artifacts are limaces; and the "Lagoa Santa" industry, completely lacking any formal artifacts, composed mainly of small quartz flakes. Our data suggests that these differences are not related to subsistence or raw-material constraints, but rather to different cultural norms and transmission of strongly divergent chaînes opératoires. Such diversity in material culture, when viewed from a cultural transmission (CT theory standpoint, seems at odds with a simple Clovis model as the origin of these three cultural traditions given the time elapsed since the first Clovis ages and the expected population structure of the early South American settlers.

  7. Spatio-temporal assessment of streamflow droughts over Southern South America: 1961-2006

    Science.gov (United States)

    Rivera, Juan Antonio; Penalba, Olga C.

    2017-08-01

    This paper performed a streamflow drought climatology considering some of the most important rivers of Southern South America, a region highly vulnerable to climatic variations, based on the analysis of monthly streamflow records. The standardized hydrological drought index (SHDI) was used in order to depict the main characteristics of droughts—number of drought events, mean duration, and mean severity—over the period 1961-2006. Firstly, the suitability of this index based on the two-parameter gamma distribution was evaluated, considering that the use of the SHDI has been limited over the region. The regional aspects of streamflow droughts were identified through a clear relationship between drought frequency and its duration, indicating different temporal variations in streamflow records over the study area. Spatial patterns exhibit heterogeneous features in terms of streamflow drought severity and can be associated to the geographical characteristics of the basins. Observed trends in the SSI are in line with the increases in precipitation totals over the second half of the twentieth century over much of the study area. Nevertheless, drought conditions are observed more often in the basins south of 40°S, in line with recent trends in large-scale climatic oscillations. The streamflow drought characteristics can provide critical values for different water-based activities, as also information to develop strategic plans that are needed for adequate water resource management considering the different climatic features over Southern South America.

  8. Solar Output Controls Periodicity in Lake Productivity and Wetness at Southernmost South America

    Science.gov (United States)

    Pérez-Rodríguez, Marta; Gilfedder, Benjamin-Silas; Hermanns, Yvonne-Marie; Biester, Harald

    2016-11-01

    Cyclic changes in total solar irradiance (TSI) during the Holocene are known to affect global climatic conditions and cause cyclic climatic oscillations, e.g., Bond events and related changes of environmental conditions. However, the processes how changes in TSI affect climate and environment of the Southern Hemisphere, especially in southernmost South America, a key area for the global climate, are still poorly resolved. Here we show that highly sensitive proxies for aquatic productivity derived from sediments of a lake near the Chilean South Atlantic coast (53 °S) strongly match the cyclic changes in TSI throughout the Holocene. Intra-lake productivity variations show a periodicity of ~200-240 years coherent with the time series of TSI-controlled cosmogenic nuclide 10Be production. In addition TSI dependent periodicity of Bond events (~1500 years) appear to control wetness at the LH site indicated by mineral matter erosion from the catchment to the lake assumingly through shifts of the position of the southern westerly wind belt. Thus, both intra-lake productivity and wetness at the southernmost South America are directly or indirectly controlled by TSI.

  9. Antimicrobial resistance among Enterobacteriaceae in South America: history, current dissemination status and associated socioeconomic factors.

    Science.gov (United States)

    Bonelli, Raquel Regina; Moreira, Beatriz Meurer; Picão, Renata Cristina

    2014-04-01

    South America exhibits some of the higher rates of antimicrobial resistance in Enterobactericeae worldwide. This continent includes 12 independent countries with huge socioeconomic differences, where the ample access to antimicrobials, including counterfeit ones, coexists with ineffective health systems and sanitation problems, favoring the emergence and dissemination of resistant strains. This work presents a literature review concerning the evolution and current status of antimicrobial resistance threats found among Enterobacteriaceae in South America. Resistance to β-lactams, fluoroquinolones and aminoglycosides was emphasized along with description of key epidemiological studies that highlight the success of specific resistance determinants in different parts of the continent. In addition, a discussion regarding political and socioeconomic factors possibly related to the dissemination of antimicrobial resistant strains in clinical settings and at the community is presented. Finally, in order to assess the possible sources of resistant bacteria, we compile the current knowledge about the occurrence of antimicrobial resistance in isolates in South American' food, food-producing animals and off-hospitals environments. By addressing that intensive intercontinental commerce and tourism neutralizes the protective effect of geographic barriers, we provide arguments reinforcing that globally integrated efforts are needed to decelerate the emergence and dissemination of antimicrobial resistant strains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Potential distribution of the invasive freshwater dinoflagellate Ceratium furcoides (Levander) Langhans (Dinophyta) in South America.

    Science.gov (United States)

    Meichtry de Zaburlín, Norma; Vogler, Roberto E; Molina, María J; Llano, Víctor M

    2016-04-01

    Dinoflagellates of the genus Ceratium are predominantly found in marine environments, with a few species in inland waters. Over the last decades, the freshwater species Ceratium hirundinella and Ceratium furcoides have colonized and invaded several South American basins. The purpose of this study was to create a distribution model for the invasive dinoflagellate C. furcoides in South America in order to further investigate the basins at potential risk, as well as the environmental conditions that influence its expansion. This species is known to develop blooms due to its mobility, resistance to sedimentation, and optimized use of resources. Although nontoxic, blooms of the species cause many problems to both the natural ecosystems and water users. Potential distribution was predicted by using a maximum entropy algorithm (MaxEnt). Model was run with 101 occurrences obtained from the scientific literature, and climatic, hydrological and topographic variables. The developed model had a very good performance for the study area. The most susceptible areas identified were mainly concentrated in the basins between southeastern Brazil and northeastern Argentina. Besides already affected regions, new potentially suitable areas were identified in temperate regions of South America. The information generated here will be useful for authorities responsible for water and watershed management to monitor the spread of this species and address problems related to its establishment in new environments.

  11. Summer precipitation variability over Southeastern South America in a global warming scenario

    Energy Technology Data Exchange (ETDEWEB)

    Junquas, C. [UPMC/CNRS, Laboratoire de Meteorologie Dynamique, Institut Pierre Simon Laplace, Ecole Polytechnique, Paris (France); UMI-IFAECI CNRS-CONICET-UBA, Centro de Investigaciones del Mar y la Atmosfera (CIMA), DCAO/FCEyN, Buenos Aires (Argentina); Vera, C. [UMI-IFAECI CNRS-CONICET-UBA, Centro de Investigaciones del Mar y la Atmosfera (CIMA), DCAO/FCEyN, Buenos Aires (Argentina); Li, L.; Le Treut, H. [UPMC/CNRS, Laboratoire de Meteorologie Dynamique, Institut Pierre Simon Laplace, Ecole Polytechnique, Paris (France)

    2012-05-15

    December-January-February (DJF) rainfall variability in southeastern South America (SESA) is studied in 18 coupled general circulation models from the WCRP/CMIP3 dataset, for present climate and the SRES-A1B climate change scenario. The analysis is made in terms of properties of the first leading pattern of rainfall variability in the region, characterized by a dipole-like structure with centers of action in the SESA and South Atlantic Convergence Zone (SACZ) regions. The study was performed to address two issues: how rainfall variability in SESA would change in a future climate and how much of that change explains the projected increasing trends in the summer mean rainfall in SESA identified in previous works. Positive (negative) dipole events were identified as those DJF seasons with above (below) normal rainfall in SESA and below (above) normal rainfall in the SACZ region. Results obtained from the multi-model ensemble confirm that future rainfall variability in SESA has a strong projection on the changes of seasonal dipole pattern activity, associated with an increase of the frequency of the positive phase. In addition, the frequency increase of positive dipole phase in the twenty first century seems to be associated with an increase of both frequency and intensity of positive SST anomalies in the equatorial Pacific, and with a Rossby wave train-like anomaly pattern linking that ocean basin to South America, which regionally induces favorable conditions for moisture transport convergence and rainfall increase in SESA. (orig.)

  12. Fire Ants (Solenopsis spp. and Their Natural Enemies in Southern South America

    Directory of Open Access Journals (Sweden)

    Juan Briano

    2012-01-01

    Full Text Available We review the fire ant research conducted by the ARS-South American Biological Control Laboratory (SABCL since 1987 to find a complex of natural enemies in southern South America and evaluate their specificity and suitability for field release as self-sustaining biological control agents. We also include those studies conducted by the ARS-Center for Medical, Agriculture, and Veterinary Entomology in the United States with the SABCL collaboration. Ecological and biological information is reported on local fire ants and their microsporidia, nematodes, viruses, phorid flies, eucharitid wasps, strepsiptera, and parasitic ants. Their biology, abundance, distribution, detrimental effect, field persistence, specificity, and phenology are discussed. We conclude that the objectives of the ARS program in South America are being achieved and that the pioneering studies have served to encourage further investigations in the United States and other countries and advanced the implementation of biological control programs to decrease imported fire ant densities and damage. Still, several promising organisms should be further investigated for eventual field release in the near future.

  13. Going like gangbusters: transnational tobacco companies "making a killing" in South America.

    Science.gov (United States)

    Stebbins, K R

    2001-06-01

    This article reports on the recent growth of transnational tobacco companies (TTCs) in South America. Although some scholarly attention has been directed toward such growth in Asia and eastern Europe, South America has also been targeted by the TTCs' aggressive expansionist practices in recent years. Fighting "Big Tobacco" is entirely different from combating most public health problems. Unlike cigarettes, most infectious diseases and maternal and child health problems never provide profits to transnational corporations and governments. Also, most public health problems (with alcohol being another notable exception) are not exacerbated by extensive advertising campaigns that promote the cause of the health problems. Supported by data gathered during three months of fieldwork in Ecuador, Peru, Chile, and Argentina in 1997, this article suggests that the TTCs' marketing strategies override cultural differences in the choices people make regarding smoking and health. Combining critical medical anthropology and public health, this article concludes that unless dramatic actions are taken, an avoidable outbreak of tobacco-related diseases will eventually reach epidemic proportions on the South American continent. It is also a "call to arms" for more medical anthropologists to investigate tobacco-related matters around the world.

  14. On Vastness and Variability: Cultural Transmission, Historicity, and the Paleoindian Record in Eastern South America.

    Science.gov (United States)

    Araujo, Astolfo G M

    2015-01-01

    Eastern South America, or what is today Brazilian territory, poses interesting questions about the early human occupation of the Americas. Three totally distinct and contemporaneous lithic technologies, dated between 11,000 and 10,000 14C BP, are present in different portions of the country: the Umbu tradition in the south, with its formal bifacial industry, with well-retouched scrapers and bifacial points; the Itaparica tradition in the central-west / northwest, totally unifacial, whose only formal artifacts are limaces; and the "Lagoa Santa" industry, completely lacking any formal artifacts, composed mainly of small quartz flakes. Our data suggests that these differences are not related to subsistence or raw-material constraints, but rather to different cultural norms and transmission of strongly divergent chaînes opératoires. Such diversity in material culture, when viewed from a cultural transmission (CT) theory standpoint, seems at odds with a simple Clovis model as the origin of these three cultural traditions given the time elapsed since the first Clovis ages and the expected population structure of the early South American settlers.

  15. Poaceae pollen grain size as a tool to distinguish past grasslands in South America: a new methodological approach

    OpenAIRE

    Schüler, Lisa; Behling, Hermann

    2010-01-01

    Despite the dominance of grasslands during the last glacial period, especially in South America, the highly uniform morphology of Poaceae pollen grains has so far allowed only very few palynological studies based on Poaceae pollen. In our study we compare two methods of distinguishing between South American grassland ecosystems based on quantitative morphology of Poaceae pollen grains. We investigated data sets from Páramo in southern Ecuador, Campos de Altitude and Campos in south-eastern an...

  16. Circulating strains of human respiratory syncytial virus in central and south America.

    Directory of Open Access Journals (Sweden)

    Merly Sovero

    Full Text Available Human respiratory syncytial virus (HRSV is a major cause of viral lower respiratory tract infections among infants and young children. HRSV strains vary genetically and antigenically and have been classified into two broad subgroups, A and B (HRSV-A and HRSV-B, respectively. To date, little is known about the circulating strains of HRSV in Latin America. We have evaluated the genetic diversity of 96 HRSV strains by sequencing a variable region of the G protein gene of isolates collected from 2007 to 2009 in Central and South America. Our results show the presence of the two antigenic subgroups of HRSV during this period with the majority belonging to the genotype HRSV-A2.

  17. Emerging Plasmodium vivax resistance to chloroquine in South America: an overview

    Directory of Open Access Journals (Sweden)

    Lígia Antunes Gonçalves

    2014-08-01

    Full Text Available The global emergence of Plasmodium vivax strains resistant to chloroquine (CQ since the late 1980s is complicating the current international efforts for malaria control and elimination. Furthermore, CQ-resistant vivax malaria has already reached an alarming prevalence in Indonesia, East Timor and Papua New Guinea. More recently, in vivo studies have documented CQ-resistant P. vivax infections in Guyana, Peru and Brazil. Here, we summarise the available data on CQ resistance across P. vivax-endemic areas of Latin America by combining published in vivo and in vitro studies. We also review the current knowledge regarding the molecular mechanisms of CQ resistance in P. vivax and the prospects for developing and standardising reliable molecular markers of drug resistance. Finally, we discuss how the Worldwide Antimalarial Resistance Network, an international collaborative effort involving malaria experts from all continents, might contribute to the current regional efforts to map CQ-resistant vivax malaria in South America.

  18. The first peopling of South America: new evidence from Y-chromosome haplogroup Q.

    Directory of Open Access Journals (Sweden)

    Vincenza Battaglia

    Full Text Available Recent progress in the phylogenetic resolution of the Y-chromosome phylogeny permits the male demographic dynamics and migratory events that occurred in Central and Southern America after the initial human spread into the Americas to be investigated at the regional level. To delve further into this issue, we examined more than 400 Native American Y chromosomes (collected in the region ranging from Mexico to South America belonging to haplogroup Q - virtually the only branch of the Y phylogeny observed in modern-day Amerindians of Central and South America - together with 27 from Mongolia and Kamchatka. Two main founding lineages, Q1a3a1a-M3 and Q1a3a1-L54(xM3, were detected along with novel sub-clades of younger age and more restricted geographic distributions. The first was also observed in Far East Asia while no Q1a3a1-L54(xM3 Y chromosome was found in Asia except the southern Siberian-specific sub-clade Q1a3a1c-L330. Our data not only confirm a southern Siberian origin of ancestral populations that gave rise to Paleo-Indians and the differentiation of both Native American Q founding lineages in Beringia, but support their concomitant arrival in Mesoamerica, where Mexico acted as recipient for the first wave of migration, followed by a rapid southward migration, along the Pacific coast, into the Andean region. Although Q1a3a1a-M3 and Q1a3a1-L54(xM3 display overlapping general distributions, they show different patterns of evolution in the Mexican plateau and the Andean area, which can be explained by local differentiations due to demographic events triggered by the introduction of agriculture and associated with the flourishing of the Great Empires.

  19. The first peopling of South America: new evidence from Y-chromosome haplogroup Q.

    Science.gov (United States)

    Battaglia, Vincenza; Grugni, Viola; Perego, Ugo Alessandro; Angerhofer, Norman; Gomez-Palmieri, J Edgar; Woodward, Scott Ray; Achilli, Alessandro; Myres, Natalie; Torroni, Antonio; Semino, Ornella

    2013-01-01

    Recent progress in the phylogenetic resolution of the Y-chromosome phylogeny permits the male demographic dynamics and migratory events that occurred in Central and Southern America after the initial human spread into the Americas to be investigated at the regional level. To delve further into this issue, we examined more than 400 Native American Y chromosomes (collected in the region ranging from Mexico to South America) belonging to haplogroup Q - virtually the only branch of the Y phylogeny observed in modern-day Amerindians of Central and South America - together with 27 from Mongolia and Kamchatka. Two main founding lineages, Q1a3a1a-M3 and Q1a3a1-L54(xM3), were detected along with novel sub-clades of younger age and more restricted geographic distributions. The first was also observed in Far East Asia while no Q1a3a1-L54(xM3) Y chromosome was found in Asia except the southern Siberian-specific sub-clade Q1a3a1c-L330. Our data not only confirm a southern Siberian origin of ancestral populations that gave rise to Paleo-Indians and the differentiation of both Native American Q founding lineages in Beringia, but support their concomitant arrival in Mesoamerica, where Mexico acted as recipient for the first wave of migration, followed by a rapid southward migration, along the Pacific coast, into the Andean region. Although Q1a3a1a-M3 and Q1a3a1-L54(xM3) display overlapping general distributions, they show different patterns of evolution in the Mexican plateau and the Andean area, which can be explained by local differentiations due to demographic events triggered by the introduction of agriculture and associated with the flourishing of the Great Empires.

  20. Climatic Impact of the Bølling-Allerød over Eastern South America

    Science.gov (United States)

    Amorim Catunda, M. C.; Chiessi, C. M.; Strikis, N. M.; Mulitza, S.; Cruz, F. W., Sr.; Vuille, M. F.

    2015-12-01

    The last deglaciation was marked by large scale and rapid changes in rainfall over the tropics. Previous studies have correlated pulses of increased terrigenous input off semi arid northeastern South America with abrupt cold events in the high latitudes of the Northern Hemisphere. However, deglacial climate changes in other areas of South America are still not resolved. Here we reconstruct deglacial (23-11.5 cal ka BP) continental conditions over eastern Brazil based on (i) Ti/Ca of a radiocarbon dated marine sediment core as a proxy for Doce River (draining eastern Brazil) terrigenous input, and (ii) δ18O of a suite of U-Th dated stalagmites from eastern Brazil. Our marine core was recovered from 1100 m water depth on the tropical Brazilian continental slope, while our stalagmites come from Lapa Sem Fim cave. Both the Doce River and Lapa Sem Fim cave are located in the highly populated and economically active eastern Brazil, where most of the rainfall is related to the activity of the South America Monsoon System (SAMS). The Ti/Ca record is relatively stable showing high proportions of Ti in relationship to Ca throughout the deglacial, with a major excursion towards lower values indicating a decrease in terrigenous input synchronous to the Bølling-Allerød. Interestingly, speleothem δ18O also record this major excursion as less negative values. Together, our results suggest a major decrease in precipitation likely related to a weakening of the SAMS. We further compared our results with the output of the SYNTRACE run of CCSM3 fully coupled climate model with transient forcing for the last deglaciation. Geochemical records and model output show a very good coupling and suggest that the eastern Brazil experienced the driest period of the whole last deglaciation during the Bølling-Allerød and this dry spell was indeed related to a decreased SAMS intensity.

  1. Multi-year GNSS monitoring of atmospheric IWV over Central and South America for climate studies

    Science.gov (United States)

    Mendoza, Luciano; Bianchi, Clara; Fernández, Laura; Natali, María Paula; Meza, Amalia; Moirano, Juan

    2017-04-01

    Atmospheric water vapour has been acknowledged as an essential climate variable. Weather prediction and hazard assessment systems benefit from real-time observations, whereas long-term records contribute to climate studies. Nowadays, ground-based GNSS products have become widely employed, complementing satellite observations over the oceans. Although the past decade has seen a significant development of the GNSS infrastructure in Central and South America, its potential for atmospheric water vapour monitoring has not been fully exploited. With this in mind, we have performed a regional, seven-year long and homogeneous analysis, comprising 136 GNSS tracking stations, obtaining high-rate and continuous observations of column integrated water vapour and troposphere zenith total delay (Bianchi et al. 2016). As preliminary application for this data set, we have estimated local water vapour trends, their significance, and their relation with specific climate regimes. We have found evidence of drying at temperate regions in South America, at a rate of about 2% per decade, while a slow moistening of the troposphere over tropical regions is also weakly suggested by our results. Furthermore, we have assessed the regional performance of the empirical model GPT2w to blindly estimate troposphere delays. The model fairly reproduces the observed mean delays, including their annual and semi-annual variations. Nevertheless, a long-term evaluation has shown systematical biases, up to 20 mm, probably inherited form the underling atmospheric reanalysis. Additionally, the complete data set has been made openly available at a scientific repository (doi:10.1594/PANGAEA.858234). References: C. Bianchi, L. Mendoza, L. Fernandez, M. P. Natali, A. Meza, J. F. Moirano, Multi-year GNSS monitoring of atmospheric IWV over Central and South America for climate studies, Ann. Geophys., ISSN 0992-7689, eISSN 1432-0576, 34 (7), 623-639 (doi:10.5194/angeo-34-623-2016).

  2. Storm-time total electron content and its response to penetration electric fields over South America

    Directory of Open Access Journals (Sweden)

    P. M. de Siqueira

    2011-10-01

    Full Text Available In this work the response of the ionosphere due to the severe magnetic storm of 7–10 November 2004 is investigated by analyzing GPS Total Electron Content (TEC maps constructed for the South America sector. In order to verify the disturbed zonal electric fields in South America during the superstorm, ionospheric vertical drift data obtained from modeling results are used in the analysis. The vertical drifts were inferred from ΔH magnetometer data (Jicamarca-Piura following the methodology presented by Anderson et al. (2004. Also used were vertical drifts measured by the Jicamarca ISR. Data from a digisonde located at São Luís, Brazil (2.33° S, 44.2° W, dip latitude 0.25° are presented to complement the Jicamarca equatorial data. Penetration electric fields were observed by the comparison between the equatorial vertical drifts and the Interplanetary Electric Field (IEF. The TEC maps obtained from GPS data reflect the ionospheric response over the South America low-latitude and equatorial region. They reveal unexpected plasma distributions and TEC levels during the main phase of the superstorm on 7 November, which is coincident with the local post-sunset hours. At this time an increase in the pre-reversal enhancement was expected to develop the Equatorial Ionization Anomaly (EIA but we observed the absence of EIA. The results also reveal well known characteristics of the plasma distributions on 8, 9, and 10 November. The emphasized features are the expansion and intensification of EIA due to prompt penetration electric fields on 9 November and the inhibition of EIA during post-sunset hours on 7, 8, and 10 November. One important result is that the TEC maps provided a bi-dimensional view of the ionospheric changes offering a spatial description of the electrodynamics involved, which is an advantage over TEC measured by isolated GPS receivers.

  3. Genetic Diversity, Distribution, and Serological Features of Hantavirus Infection in Five Countries in South America

    Science.gov (United States)

    Padula, P. J.; Colavecchia, S. B.; Martínez, V. P.; Gonzalez Della Valle, M. O.; Edelstein, A.; Miguel, S. D. L.; Russi, J.; Riquelme, J. Mora; Colucci, N.; Almirón, M.; Rabinovich, R. D.

    2000-01-01

    Since 1995 when the first case of hantavirus pulmonary syndrome (HPS) was reported in Patagonia, there have been more than 400 cases of HPS reported in five countries in South America. The first case of HPS was associated with Andes (AND) virus. In this study, we report on the genetic diversity, geographical distribution, and serological features of hantavirus infection in six countries in South America based on 87 HPS cases from Argentina, Bolivia, Chile, Paraguay, and Uruguay. An early immunoglobulin M (IgM), IgA, and IgG humoral response was observed in almost all HPS cases. The IgM response appears to peak 1 or 2 days after the onset of symptoms. Peak IgG antibody titers occur mostly after the first week. Low IgG titers or the absence of IgG was associated with higher mortality rates. The IgA response peaks around day 15 and then rapidly decreases. The results of phylogenetic analysis based on partial M-fragment G1- and G2-encoding sequences showed that HPS cases from the five countries were infected with viruses related to AND or Laguna Negra (LN) virus. Within AND virus-infected persons, at least five major genetic lineages were found; one lineage was detected in Uruguayan and Argentinean cases from both sides of the Rio de la Plata river. Two Paraguayan patients were infected with a virus different from LN virus. According to the results of phylogenetic analyses, this virus probably belongs to a distinct lineage related more closely to the AND virus than to the LN virus, suggesting that there is probably an Oligoryzomys-borne viral variant circulating in Paraguay. These studies may contribute to a better understanding of hantavirus human infection in South America. PMID:10921972

  4. A new species of Amblyodus Westwood, 1878 (Coleoptera, Melolonthidae, Dynastinae from South America

    Directory of Open Access Journals (Sweden)

    Paschoal Grossi

    2011-01-01

    Full Text Available A second species of Amblyodus Westwood, 1878, A. castroi sp. n., is described from the northern South America based on 12 specimens from Brazil and Peru (Amazonian subregion. The new species is here compared with the type species of the genus, A. taurus Westwood, 1878 and both species and their male genitalia are illustrated. Diagnostic characters for the genus are discussed, especially the metatibial teeth. A distribution map including the type species and the new species is provided. The genus Amblyodus is recorded for the first time from Peru and from Brazil states of Pará and Rondônia.

  5. A new species of Amblyodus Westwood, 1878 (Coleoptera, Melolonthidae, Dynastinae) from South America.

    Science.gov (United States)

    Grossi, Paschoal Coelho; Grossi, Everardo José

    2011-01-12

    A second species of Amblyodus Westwood, 1878, Amblyodus castroisp. n., is described from the northern South America based on 12 specimens from Brazil and Peru (Amazonian subregion). The new species is here compared with the type species of the genus, Amblyodus taurus Westwood, 1878 and both species and their male genitalia are illustrated. Diagnostic characters for the genus are discussed, especially the metatibial teeth. A distribution map including the type species and the new species is provided. The genus Amblyodus is recorded for the first time from Peru and from Brazil states of Pará and Rondônia.

  6. COELIAC DISEASE IN CENTRAL AND SOUTH AMERICA: time for a concerted approach to its epidemiology

    Directory of Open Access Journals (Sweden)

    Affifa FARRUKH

    2015-06-01

    Full Text Available Central and South America offer an opportunity to resolve some of the current controversies that surround the epidemiology of celiac disease. Through a concerted action which brings together clinicians, researchers and patients there is an opportunity to establish robust data sets which will allow detailed analysis of environmental and genetic factors. In this review available data from the continent together with data from Spain and Italy are drawn together to give a current picture in the hope that it will stimulate further research.

  7. Evaluation of existing knowledge of the tectonic history and lithospheric structure of South America

    Science.gov (United States)

    Keller, G. R.; Lidiak, E. G. (Principal Investigator)

    1980-01-01

    While data is available on the lithospheric and crustal structure of the Andes region of South America, there is limited knowledge of these aspects of the eastern portion of the continent. For this reason, a surface wave dispersion study of the area was initiated. Long period seismograms were obtained for a tripartite analysis of dispersion. A flow chart of the analysis to be conducted is presented along with a preliminary geologic/tectonic map that was prepared. Efforts to characterize the provinces identified in terms of their geological and geophysical parameters continue.

  8. Mayaro virus disease: an emerging mosquito-borne zoonosis in tropical South America.

    Science.gov (United States)

    Tesh, R B; Watts, D M; Russell, K L; Damodaran, C; Calampa, C; Cabezas, C; Ramirez, G; Vasquez, B; Hayes, C G; Rossi, C A; Powers, A M; Hice, C L; Chandler, L J; Cropp, B C; Karabatsos, N; Roehrig, J T; Gubler, D J

    1999-01-01

    This report describes the clinical, laboratory, and epidemiological findings on 27 cases of Mayaro virus (MV) disease, an emerging mosquito-borne viral illness that is endemic in rural areas of tropical South America. MV disease is a nonfatal, dengue-like illness characterized by fever, chills, headache, eye pain, generalized myalgia, arthralgia, diarrhea, vomiting, and rash of 3-5 days' duration. Severe joint pain is a prominent feature of this illness; the arthralgia sometimes persists for months and can be quite incapacitating. Cases of two visitors from the United States, who developed MV disease during visits to eastern Peru, are reported. MV disease and dengue are difficult to differentiate clinically.

  9. The carbon balance of South America: status, decadal trends and main determinants

    Directory of Open Access Journals (Sweden)

    M. Gloor

    2012-01-01

    Full Text Available We attempt to summarize the carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric environment and climate. Flux estimation methods which we consider sufficiently reliable are fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and finally inventories of agricultural exports. Other routes to estimating land-atmosphere CO2 fluxes include atmospheric transport inverse modelling and vegetation model predictions but are hampered by the data paucity and the need for improved parameterisation. The available data we analyze suggest that South America was a net source to the atmosphere during the 1980s (∼0.3–0.4 Pg C yr−1 and close to neutral (∼0.1 Pg C yr−1 in the 1990s with carbon uptake in old-growth forests nearly compensating carbon losses due to fossil fuel burning and deforestation. Annual mean precipitation over tropical South America measured by Amazon River discharge has a long-term upward trend, although over the last decade, dry seasons have tended to be drier and longer (and thus wet seasons wetter, with the years 2005 and 2010 experiencing strong droughts. It is currently unclear what the effect of these climate changes on the old-growth forest carbon sink will be but first measurements suggest it may be weakened. Based on scaling of forest census data the net carbon balance of South America seems to have been an increased source roughly over the 2005–2010 period (a total of ∼1 Pg C of dead tree biomass released over several years due to forest drought response. Finally, economic development of the tropical forest regions of the continent is advancing steadily with exports of agricultural products being an important driver and witnessing a strong upturn over the

  10. Rearming and Low Perception of International Threat in South America: Is that Coexistence Possible?

    Directory of Open Access Journals (Sweden)

    Jorge M. Battaglino

    2010-01-01

    Full Text Available The purpose of this article is to critically analyze the use of the concept of rearmament to explain the purchases of arms in South America. The use of this term has not only contributed to the conceptual confusion but also to a risky political use of it. The concept rearmament has a specific historical meaning which is often link to situations of acute perceptions of threat among states and to the imminent break of war. From a theoretical and empirical perspective, neither the historical understanding of the concept nor its empirical referents are present in the region.

  11. Vegetation and climate variability in tropical and subtropical South America during the late Quaternary

    Science.gov (United States)

    Behling, H.

    2013-05-01

    Detailed palynological studies from different ecosystems in tropical and subtropical South America reflect interesting vegetation and climate dynamics, in particular during glacial and late glacial times. Records from ecosystems such as the Amazon rainforest, savanna, Caatinga, Atlantic rainforest, Araucaria forest and grasslands provide interesting insight of past climate variability. The influence of events such as Dansgaard-Oeschger, Heinnrich stadials, changes in the thermohaline circulation (THC) will be discussed. In particular the Younger Dryas (YD) period shows at different places distinct vegetational changes, revealing unexpected past climatic conditions.

  12. Diarrhea and respiratory symptoms among travelers to Asia, Africa, and South and Central America from Scotland.

    Science.gov (United States)

    Redman, Christopher Allan; Maclennan, Alice; Wilson, Eleanor; Walker, Eric

    2006-01-01

    Surveillance using admissions to hospital, while being useful, is a poor indicator of the real incidence of disease encountered by travelers. An alternative is self-reported illness among those who attended at a pretravel clinic prior to their travels. Estimates of incidence and risk factors were determined for attendees at a travel clinic in Scotland using a questionnaire. Analysis for risk factors was carried out for those travelers visiting countries in Africa, Asia, or South and Central America, who had traveled for 1 week or more and had returned between 1997 and 2001 (N= 4,856). Multivariate logistic regression was used to test the hypotheses that time abroad and age-group would be significant for both respiratory and diarrheal symptoms regardless of which of the three geographical areas are visited. From 2006 returned questionnaires (response rate = 41.3%), diarrhea and respiratory symptoms were reported by 44.2 and 16.8% of respondents, respectively; the incidence was significantly greater among travelers to Asia for both diarrheal (55.5%) and respiratory (23.7%) symptoms than among travelers to Africa (36.6 and 12.2%, respectively) or South and Central America (39.5 and 16.2%, respectively). For diarrhea, age was a highly significant risk factor for travelers to Asia, South and Central America, and Africa. Being a self-organized tourist/backpacker, traveling to Asia was associated with increased risk, while for Africa and South and Central America visiting family or friends was associated with a lower risk. For travelers to Asia, traveling to the Indian subcontinent was significantly associated with increased risk. The majority of travelers had an adverse event while traveling abroad, with diarrhea and respiratory conditions being especially common despite attending a travel clinic for advice prior to departure. However, the limitations of this surveillance-based strategy have highlighted the requirement for more research to understand more fully the

  13. Cassava in South America, Brazil's contribution and the lesson to be learned from India.

    Science.gov (United States)

    Nassar, Nagib M A

    2006-11-30

    South America is responsible for about half of the cassava world production. In the 1970's productivity of the crop on the continent was about 15 ton/ha, and dropped continuously until reaching 12 ton/ha in 2004. India's productivity of cassava increased from 10 ton/ha in the 1970's to 28 ton/ha in 2004. Brazil contributed significantly to improving cassava crops through the Instituto Agronômico de Campinas in the 1960's and 1970's. The Universidade de Brasília released high-protein content hybrids, apomictic clones and explored the potential of indigenous landraces.

  14. UNASUR Health: A quiet revolution in health diplomacy in South America.

    Science.gov (United States)

    Herrero, María Belén; Tussie, Diana

    2015-12-01

    Since the creation of Union of South American Nations (UNASUR), health policies became a strategic factor in South America to collectively balance the legacy of neoliberal policies in the region. The aim of this article is first to describe the social, political, and economic processes that explain the emergence of UNASUR and its focus on social policy through healthcare. We then analyze how by virtue of UNASUR's Health Council, healthcare became the spearhead of cooperation giving way to novel forms of diplomacy. In so doing, this article contributes to a broader understanding of the regional health diplomacy and the process of unasurization of health policies as the process of building a new health framework.

  15. [Tobacco advertisement exposure and tobacco consumption among youths in South America].

    Science.gov (United States)

    Plamondon, Geneviève; Guindon, G Emmanuel; Paraje, Guillermo

    2017-01-01

    To assesses the statistical association between exposure to tobacco marketing and tobacco consumption among adolescents in South America, by using data from the Global Youth Tobacco Survey. Using data from the Global Youth Tobacco Survey (GYTS), the exposure to tobacco marketing at the school level was studied from advertising in TV, radio, massive public events and street advertisement. Tobacco behaviour was considered. The total pooled sample used was 134 073 youths from Argentina, Bolivia, Chile, Peru, Brazil, Uruguay, Suriname, Colombia, Guyana, Ecuador, Paraguay and Venezuela. The exposure to tobacco marketing is positively and significantly associated to the probability of youths experimenting with tobacco (at least once in their lifetime). For regular smokers, exposure to tobacco marketing is positively and significantly associated to smoking intensity. These results call for the implementation of strong restrictions on tobacco advertisement of various types in South American countries.

  16. Tobacco advertisement exposure and tobacco consumption among youths in South America

    Directory of Open Access Journals (Sweden)

    Geneviéve Plamondon

    2017-03-01

    Full Text Available Objective. To assesses the statistical association between exposure to tobacco marketing and tobacco consumption among adolescents in South America, by using data from the Global Youth Tobacco Survey. Materials and methods. Using data from the Global Youth Tobacco Survey (GYTS, the exposure to tobacco marketing at the school level was studied from advertising in TV, radio, massive public events and street advertisement. Tobacco behaviour was considered. The total pooled sample used was 134 073 youths from Argentina, Bolivia, Chile, Peru, Brazil, Uruguay, Suriname, Colombia, Guyana, Ecuador, Paraguay and Venezuela. Results. The exposure to tobacco marketing is positively and significantly associated to the probability of youths experimenting with tobacco (at least once in their lifetime. For regular smokers, exposure to tobacco marketing is positively and significantly associated to smoking intensity. Conclusions. These results call for the implementation of strong restrictions on tobacco advertisement of various types in South American countries.

  17. Late Pliocene Glyptodontinae (Xenarthra, Cingulata, Glyptodontidae) of South and North America: Morphology and paleobiogeographical implications in the GABI

    Science.gov (United States)

    Zurita, Alfredo E.; Carlini, Alfredo A.; Gillette, David; Sánchez, Rodolfo

    2011-03-01

    Knowledge of the main aspects of the Great American Biotic Interchange (GABI) concerning the glyptodontine Glyptodontidae (Xenarthra) is very scarce. A bidirectional dispersal process was recently proposed for this clade, with the presence of the North American genus Glyptotherium Osborn recognized in latest Pleistocene sediments of northern South America (Venezuela and Brazil). However, the earliest stages of this paleobiogeographical process remain poorly understood, mainly because of the limited fossil record on this clade in late Pliocene sediments. The goals of this contribution are: a) to present and describe the first record of a glyptodontine glyptodontid from the late Pliocene of northern South America, tentatively assigned to a new species of Boreostemma Carlini et al. ( Boreostemma? sp. nov); and b) to analyze its paleobiogeographical implications with respect to the GABI. This new material was recovered from the San Gregorio Formation (late Pliocene, prior the GABI) in northern Venezuela, where it is represented by several osteoderms of the dorsal carapace. A comparison among the three known late Pliocene glyptodontine glyptodontids of a) southern South America ( Paraglyptodon), b) northern South America ( Boreostemma), and c) southern North America (" Glyptotherium"), reveals a series of shared characters between (b) and (c), not present in (a). The most important of these shared characters in (b) and (c) are: all the osteoderms present a great development of the central figure, which is always larger than the peripherals; the sulcus that delimits the central and peripheral figures is narrower and shallower; and all the osteoderms present are relatively thin. This evidence suggests that the lineage of Glyptodontinae which participated in the GABI and subsequently diversified in North America originated in northern South America. Moreover, the evident morphological differences between these glyptodontines with respect to the southern South American

  18. Marine biodiversity in the Atlantic and Pacific coasts of South America: knowledge and gaps.

    Directory of Open Access Journals (Sweden)

    Patricia Miloslavich

    Full Text Available The marine areas of South America (SA include almost 30,000 km of coastline and encompass three different oceanic domains--the Caribbean, the Pacific, and the Atlantic--ranging in latitude from 12∘N to 55∘S. The 10 countries that border these coasts have different research capabilities and taxonomic traditions that affect taxonomic knowledge. This paper analyzes the status of knowledge of marine biodiversity in five subregions along the Atlantic and Pacific coasts of South America (SA: the Tropical East Pacific, the Humboldt Current,the Patagonian Shelf, the Brazilian Shelves, and the Tropical West Atlantic, and it provides a review of ecosystem threats and regional marine conservation strategies. South American marine biodiversity is least well known in the tropical subregions (with the exception of Costa Rica and Panama. Differences in total biodiversity were observed between the Atlantic and Pacific oceans at the same latitude. In the north of the continent, the Tropical East Pacific is richer in species than the Tropical West Atlantic, however, when standardized by coastal length, there is very little difference among them. In the south, the Humboldt Current system is much richer than the Patagonian Shelf. An analysis of endemism shows that 75% of the species are reported within only one of the SA regions, while about 22% of the species of SA are not reported elsewhere in the world. National and regional initiatives focusing on new exploration, especially to unknown areas and ecosystems, as well as collaboration among countries are fundamental to achieving the goal of completing inventories of species diversity and distribution.These inventories will allow accurate interpretation of the biogeography of its two oceanic coasts and latitudinal trends,and will also provide relevant information for science based policies.

  19. Molecular Epidemiology and Spatio-Temporal Dynamics of the H3N8 Equine Influenza Virus in South America

    Directory of Open Access Journals (Sweden)

    Cecilia Olguin Perglione

    2016-10-01

    Full Text Available Equine influenza virus (EIV is considered the most important respiratory pathogen of horses as outbreaks of the disease lead to substantial economic losses. The H3N8 EIV has caused respiratory disease in horses across the world, including South American countries. Nucleotide and deduced amino acid sequences for the complete haemagglutinin gene of the H3N8 EIV detected in South America since 1963 were analyzed. Phylogenetic and Bayesian coalescent analyses were carried out to study the origin, the time of the most recent common ancestors (tMRCA, the demographic and the phylogeographic patterns of the H3N8 EIV. The phylogenetic analysis demonstrated that the H3N8 EIV detected in South America grouped in 5 well-supported monophyletic clades, each associated with strains of different origins. The tMRCA estimated for each group suggested that the virus was circulating in North America at least one year before its effective circulation in the South American population. Phylogenetic and coalescent analyses revealed a polyphyletic behavior of the viruses causing the outbreaks in South America between 1963 and 2012, possibly due to the introduction of at least 4 different EIVs through the international movement of horses. In addition, phylodynamic analysis suggested South America as the starting point of the spread of the H3N8 EIV in 1963 and showed migration links from the United States to South America in the subsequent EIV irruptions. Further, an increase in the relative genetic diversity was observed between 2006 and 2007 and a subsequent decline since 2009, probably due to the co-circulation of different lineages and as a result of the incorporation of the Florida clade 2 strain in vaccines, respectively. The observed data highlight the importance of epidemiological surveillance and the implementation of appropriate quarantine procedures to prevent outbreaks of the disease.

  20. Molecular Epidemiology and Spatio-Temporal Dynamics of the H3N8 Equine Influenza Virus in South America

    Science.gov (United States)

    Olguin Perglione, Cecilia; Golemba, Marcelo D.; Torres, Carolina; Barrandeguy, Maria

    2016-01-01

    Equine influenza virus (EIV) is considered the most important respiratory pathogen of horses as outbreaks of the disease lead to substantial economic losses. The H3N8 EIV has caused respiratory disease in horses across the world, including South American countries. Nucleotide and deduced amino acid sequences for the complete haemagglutinin gene of the H3N8 EIV detected in South America since 1963 were analyzed. Phylogenetic and Bayesian coalescent analyses were carried out to study the origin, the time of the most recent common ancestors (tMRCA), the demographic and the phylogeographic patterns of the H3N8 EIV. The phylogenetic analysis demonstrated that the H3N8 EIV detected in South America grouped in 5 well-supported monophyletic clades, each associated with strains of different origins. The tMRCA estimated for each group suggested that the virus was circulating in North America at least one year before its effective circulation in the South American population. Phylogenetic and coalescent analyses revealed a polyphyletic behavior of the viruses causing the outbreaks in South America between 1963 and 2012, possibly due to the introduction of at least 4 different EIVs through the international movement of horses. In addition, phylodynamic analysis suggested South America as the starting point of the spread of the H3N8 EIV in 1963 and showed migration links from the United States to South America in the subsequent EIV irruptions. Further, an increase in the relative genetic diversity was observed between 2006 and 2007 and a subsequent decline since 2009, probably due to the co-circulation of different lineages and as a result of the incorporation of the Florida clade 2 strain in vaccines, respectively. The observed data highlight the importance of epidemiological surveillance and the implementation of appropriate quarantine procedures to prevent outbreaks of the disease. PMID:27754468

  1. Sediment provenance and paleoenvironmental changes in the northwestern shelf mud area of the South China Sea since the mid-Holocene

    Science.gov (United States)

    Xu, Fangjian; Hu, Bangqi; Dou, Yanguang; Liu, Xiting; Wan, Shiming; Xu, Zhaokai; Tian, Xu; Liu, Zhaoqing; Yin, Xuebo; Li, Anchun

    2017-07-01

    The late Quaternary paleoceanography and paleoenvironment of the South China Sea (SCS) have been well reconstructed over the last decade. In contrast, the provenance of the terrigenous sediments that have accumulated in the northwestern continental shelf mud area remains enigmatic. This study investigated the provenance of these sediments and the paleoenvironmental changes archived in Core X2 via the analysis of geochemical elements, grain size, and accelerator mass spectrometry (AMS) 14C ages. Based on the upper continental crust (UCC)-normalized REE patterns and REE fractionation parameters, southwestern and western Taiwanese rivers and the Pearl River were identified as the main sources of the fine-grained sediment deposited in the northwestern shelf mud area off Hainan Island. This finding further confirms the long-distance transport (> 1000 km) of fine-grained sediment from Taiwanese rivers to the northern SCS shelf and slope. Obvious changes in the grain size and Chemical Index of Alteration (CIA) record occurred at approximately 4.0 cal kyr BP and were likely caused by increased Hainan Island inputs due to sea level changes.

  2. Persistent organic pollutants in juvenile Magellanic Penguins (Spheniscus magellanicus) in South America.

    Science.gov (United States)

    Baldassin, P; Taniguchi, S; Gallo, H; Maranho, A; Kolesnikovas, C; Amorim, D B; Mansilla, M; Navarro, R M; Tabeira, L C; Bicego, M C; Montone, R C

    2016-04-01

    Magellanic penguins, Spheniscus magellanicus, are the most abundant penguins living in temperate regions of South America and are good indicators of environmental pollution in the region. Persistent organic pollutants (POPs) were detected in the liver of Magellanic penguins found debilitated or dead on the beaches of Brazil (states of Rio de Janeiro, Sao Paulo, Santa Catarina and Rio Grande do Sul) between 2008 and 2012 as well as in Uruguay and Chile in 2011. Polychlorinated biphenyls (PCBs) were more prevalent than organochlorine pesticides (DDTs ∼ HCB ∼ Drins) and polybrominated diphenyl ethers (PBDEs). Among PCBs, penta-, hexa- and hepta-chlorinated congeners were predominant. Concentrations of POPs were similar between the Pacific and Atlantic penguin populations, except for PCBs, which were relatively higher in the Pacific population. During the study years (2008-2012), large variations were found in organochlorine pesticides and PCBs tended to decline. Overall, the southern portion of South America has low concentrations of POPs, with either a constant trend or evidence of decline. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. A new enigmatic Late Miocene mylodontoid sloth from northern South America

    Science.gov (United States)

    Rincón, Ascanio D.; McDonald, H. Gregory; Solórzano, Andrés; Flores, Mónica Núñez; Ruiz-Ramoni, Damián

    2015-01-01

    A new genus and species of sloth (Eionaletherium tanycnemius gen. et sp. nov.) recently collected from the Late Miocene Urumaco Formation, Venezuela (northern South America) is herein described based on a partial skeleton including associated femora and tibiae. In order to make a preliminary analysis of the phylogenetic affinities of this new sloth we performed a discriminate analysis based on several characters of the femur and tibia of selected Mylodontoidea and Megatherioidea sloths. The consensus tree produced indicates that the new sloth, E. tanycnemius, is a member of the Mylodontoidea. Surprisingly, the new taxon shows some enigmatic features among Neogene mylodontoid sloths, e.g. femur with a robust lesser trochanter that projects medially and the straight distinctly elongated tibia. The discovery of E. tanycnemius increases the diversity of sloths present in the Urumaco sequence to ten taxa. This taxon supports previous studies of the sloth assemblage from the Urumaco sequence as it further indicates that there are several sloth lineages present that are unknown from the better sampled areas of southern South America. PMID:26064594

  4. Multi-year GNSS monitoring of atmospheric IWV over Central and South America for climate studies

    Science.gov (United States)

    Bianchi, Clara Eugenia; Mendoza, Luciano Pedro Oscar; Fernández, Laura Isabel; Natali, María Paula; Meza, Amalia Margarita; Francisco Moirano, Juan

    2016-07-01

    Atmospheric water vapour has been acknowledged as an essential climate variable. Weather prediction and hazard assessment systems benefit from real-time observations, whereas long-term records contribute to climate studies. Nowadays, ground-based global navigation satellite system (GNSS) products have become widely employed, complementing satellite observations over the oceans. Although the past decade has seen a significant development of the GNSS infrastructure in Central and South America, its potential for atmospheric water vapour monitoring has not been fully exploited. With this in mind, we have performed a regional, 7-year-long and homogeneous analysis, comprising 136 GNSS tracking stations, obtaining high-rate and continuous observations of column-integrated water vapour and troposphere zenith total delay. As a preliminary application for this data set, we have estimated local water vapour trends, their significance, and their relation with specific climate regimes. We have found evidence of drying at temperate regions in South America, at a rate of about 2 % per decade, while a slow moistening of the troposphere over tropical regions is also weakly suggested by our results. Furthermore, we have assessed the regional performance of the empirical model GPT2w to blindly estimate troposphere delays. The model reproduces the observed mean delays fairly well, including their annual and semi-annual variations. Nevertheless, a long-term evaluation has shown systematical biases, up to 20 mm, probably inherited from the underlying atmospheric reanalysis. Additionally, the complete data set has been made openly available as supplementary material.

  5. Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii in South America.

    Science.gov (United States)

    Rodríguez, Carlos Hernán; Balderrama Yarhui, Norah; Nastro, Marcela; Nuñez Quezada, Tamara; Castro Cañarte, Glenda; Magne Ventura, Raquel; Ugarte Cuba, Tayita; Valenzuela, Natalia; Roach, Freddy; Mota, María Inés; Burger, Noelia; Velázquez Aguayo, Gladys; Ortellado-Canese, Juana; Bruni, Geni; Pandolfo, Cecilia; Bastyas, Nadya; Famiglietti, Angela

    2016-10-01

    One hundred and twenty-six epidemiologically sequential, unrelated, carbapenem-resistant Acinetobacter baumannii isolates from nine hospitals in six countries of South America were collected between July 2013 and June 2014. Genes coding for Ambler class D and B carbapenemases were sought by PCR. All isolates were typed using the 3-locus sequence typing and blaOXA-51-like sequence-based typing techniques. The blaOXA-23 gene was recovered in all the participating hospitals and in all the isolates of seven of nine medical centres. The blaOXA-72 gene was only recovered in the two medical centres from Guayaquil city, Ecuador. Trilocus sequence typing revealed the presence of sequence groups SG2, SG4 and SG5. blaOXA-51-like sequence-based typing revealed the presence of blaOXA-132, blaOXA-65, blaOXA-69 and blaOXA-64. Our results showed that the population of carbapenem-resistant A. baumannii in South America was principally associated with ST79, ST25 and ST15 (92 %) and harboured the blaOXA-23 gene mainly. CC2 was not detected.

  6. Long-term trends and interannual variability of fires in South America during 2001-2009

    Science.gov (United States)

    Chen, Y.; Randerson, J. T.; Morton, D. M.; Jin, Y.; Giglio, L.; Collatz, G. J.; Kasibhatla, P. S.; van der Werf, G.; Defries, R. S.

    2010-12-01

    Forest and savanna fires in South America have large impacts on ecosystems, air quality, and global climate. In this paper we investigated long-term trends and interannual variability of forest and savanna fires in South America during 2001-2009 based on multiple satellite datasets. We found that fires associated with the deforestation frontier in evergreen forests increased in the first half of the decade, peaked at 2005, and declined thereafter. Fires in deciduous forests in southern Bolivia, northern Argentina and western Paraguay were characterized by a consistent increasing trend. Savanna fires showed smaller interannual variability, except for a high (2007) and a low (2009) year. Time series of fire counts (FC), burned area, and GFED3 emissions demonstrated a moving fire front in the deforestation arc toward the interior of the Amazon. Fire intensity (FI), defined as the ratio of FC to the deforestation area, increased consistently during 2001-2007 and decreased in 2008. Fire persistence (FP), which is linked with high rates of fuel consumption including repeated human aggregation and burning of fuels, decreased at the deforestation frontier after 2004. We explored the possibility of using FP to estimate the FI and the deforestation area. The interannual variability of fire activity was found to be correlated with precipitation with variable time lags in different biomes. Climate variability and drought stress were related to ENSO and the North Atlantic Oscillation.

  7. Preferential host switching and its relation with Hantavirus diversification in South America.

    Science.gov (United States)

    Rivera, Paula C; González-Ittig, Raul E; Gardenal, Cristina N

    2015-09-01

    In recent years, the notion of co-speciation between Hantavirus species and their hosts was discarded in favour of a more likely explanation: preferential host switching. However, the relative importance of this last process in shaping the evolutionary history of hantaviruses remains uncertain, given the present limited knowledge not only of virus-host relationships but also of the pathogen and reservoir phylogenies. In South America, more than 25 hantavirus genotypes were detected; several of them act as aetiological agents of hantavirus pulmonary syndrome (HPS). An understanding of the diversity of hantaviruses and of the processes underlying host switching is critical since human cases of HPS are almost exclusively the result of human-host interactions. In this study, we tested if preferential host switching is the main process driving hantavirus diversification in South America, by performing a co-phylogenetic analysis of the viruses and their primary hosts. We also suggest a new level of amino acid divergence to define virus species in the group. Our results indicate that preferential host switching would not be the main process driving virus diversification. The historical geographical proximity among rodent hosts emerges as an alternative hypothesis to be tested.

  8. Climate change hotspots over South America: from CMIP3 to CMIP5 multi-model datasets

    Science.gov (United States)

    Torres, Roger Rodrigues; Marengo, Jose Antonio

    2014-08-01

    This study identifies possible hotspots of climate change in South America through an examination of the spatial pattern of the Regional Climate Change Index (RCCI) over the region by the end of the twenty-first century. The RCCI is a qualitative index that can synthesize a large number of climate model projections, and it is suitable for identifying those regions where climate change could be more pronounced in a warmer climate. The reliability and uncertainties of the results are evaluated by using numerous state-of-the-art general circulation models (GCMs) and forcing scenarios from the Coupled Model Intercomparison Project phases 3 and 5. The results show that southern Amazonia and the central-western region and western portion of Minas Gerais state in Brazil are persistent climate change hotspots through different forcing scenarios and GCM datasets. In general, as the scenarios vary from low- to high-level forcing, the area of high values of RCCI increase and the magnitude intensify from central-western and southeast Brazil to northwest South America. In general, the climatic hotspots identified in this study are characterized by an increase of mean surface air temperature, mainly in the austral winter; by an increase of interannual temperature variability, predominantly in the austral summer; and by a change in the mean and interannual variability of precipitation during the austral winter.

  9. Mycobacterium tuberculosis strains of the Beijing genotype are rarely observed in tuberculosis patients in South America

    Directory of Open Access Journals (Sweden)

    Viviana Ritacco

    2008-08-01

    Full Text Available The frequency of the Beijing genotype of Mycobacterium tuberculosis as a cause of tuberculosis (TB in South America was determined by analyzing genotypes of strains isolated from patients that had been diagnosed with the disease between 1997 and 2003 in seven countries of the subcontinent. In total, 19 of the 1,202 (1.6% TB cases carried Beijing isolates, including 11 of the 185 patients from Peru (5.9%, five of the 512 patients from Argentina (1.0%, two of the 252 Brazilian cases (0.8%, one of the 166 patients from Paraguay (0.6% and none of the samples obtained from Chile (35, Colombia (36 and Ecuador (16. Except for two patients that were East Asian immigrants, all cases with Beijing strains were native South Americans. No association was found between carrying a strain with the Beijing genotype and having drug or multi-drug resistant disease. Our data show that presently transmission of M. tuberculosis strains of the Beijing genotype is not frequent in Latin America. In addition, the lack of association of drug resistant TB and infection with M. tuberculosis of the Beijing genotype observed presently demands efforts to define better the contribution of the virulence and lack of response to treatment to the growing spread of Beijing strains observed in other parts of the world.

  10. Phylogeny and cryptic diversity in geckos (Phyllopezus; Phyllodactylidae; Gekkota) from South America's open biomes.

    Science.gov (United States)

    Gamble, Tony; Colli, Guarino R; Rodrigues, Miguel T; Werneck, Fernanda P; Simons, Andrew M

    2012-03-01

    The gecko genus Phyllopezus occurs across South America's open biomes: Cerrado, Seasonally Dry Tropical Forests (SDTF, including Caatinga), and Chaco. We generated a multi-gene dataset and estimated phylogenetic relationships among described Phyllopezus taxa and related species. We included exemplars from both described Phyllopezus pollicaris subspecies, P. p. pollicaris and P. p.przewalskii. Phylogenies from the concatenated data as well as species trees constructed from individual gene trees were largely congruent. All phylogeny reconstruction methods showed Bogertia lutzae as the sister species of Phyllopezus maranjonensis, rendering Phyllopezus paraphyletic. We synonymized the monotypic genus Bogertia with Phyllopezus to maintain a taxonomy that is isomorphic with phylogenetic history. We recovered multiple, deeply divergent, cryptic lineages within P. pollicaris. These cryptic lineages possessed mtDNA distances equivalent to distances among other gekkotan sister taxa. Described P. pollicaris subspecies are not reciprocally monophyletic and current subspecific taxonomy does not accurately reflect evolutionary relationships among cryptic lineages. We highlight the conservation significance of these results in light of the ongoing habitat loss in South America's open biomes. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. A new enigmatic Late Miocene mylodontoid sloth from northern South America.

    Science.gov (United States)

    Rincón, Ascanio D; McDonald, H Gregory; Solórzano, Andrés; Flores, Mónica Núñez; Ruiz-Ramoni, Damián

    2015-02-01

    A new genus and species of sloth (Eionaletherium tanycnemius gen. et sp. nov.) recently collected from the Late Miocene Urumaco Formation, Venezuela (northern South America) is herein described based on a partial skeleton including associated femora and tibiae. In order to make a preliminary analysis of the phylogenetic affinities of this new sloth we performed a discriminate analysis based on several characters of the femur and tibia of selected Mylodontoidea and Megatherioidea sloths. The consensus tree produced indicates that the new sloth, E. tanycnemius, is a member of the Mylodontoidea. Surprisingly, the new taxon shows some enigmatic features among Neogene mylodontoid sloths, e.g. femur with a robust lesser trochanter that projects medially and the straight distinctly elongated tibia. The discovery of E. tanycnemius increases the diversity of sloths present in the Urumaco sequence to ten taxa. This taxon supports previous studies of the sloth assemblage from the Urumaco sequence as it further indicates that there are several sloth lineages present that are unknown from the better sampled areas of southern South America.

  12. Shifts in composition of avian communities related to temperate-grassland afforestation in southeastern South America

    Directory of Open Access Journals (Sweden)

    Rafael A. Dias

    2013-03-01

    Full Text Available Afforestation of temperate grasslands with fast-growing trees for industrial pulpwood production is spreading in South America. Despite high afforestation rates resulting from governmental policies that stimulate pulpwood production in grasslands of southern Brazil and Uruguay, the impact of this activity on biodiversity remains to be properly assessed. We used an Impact-Reference study design to evaluate how grassland afforestation affects the composition of grassland bird assemblages. We sampled eucalyptus plantations and neighboring natural grasslands in southern Brazil from 2006-2009, and relied on nested sampling and analysis to separate the effects of afforestation from the natural variability of grasslands. We recorded a significant difference in composition between assemblages from grasslands and tree plantations. Species adapted to open, treeless areas tended to be negatively affected in relation to edge or forest birds in eucalyptus plantations. Afforestation is systematically replacing the bird assemblage of hilltop grasslands by a collection of common edge and forest species that occur in nearby riverine and hillside forests. Although most grassland birds negatively affected by tree plantations are common and widespread, observed and predicted afforestation rates in southeastern South America may result in regional population reductions in the near future.

  13. South America Low-Level Jet and its effects on the precipitation over La Plata Basin

    Science.gov (United States)

    Llopart, Marta; Coppola, Erika; Giorgi, Filippo

    2015-04-01

    Studies with climate models have shown a dry bias in precipitation over La Plata Basin region for both regional and global models, which suggests a common deficiency in simulating the precipitation of the region. These deficiencies could be tied with the models parameterizations, which are not able to capture the dynamical systems as for example the low level jet, resulting in a weak latitudinal and meridional moisture transport. The goal of this work was to analyze the simulated South America low level jet and its impacts on the precipitation over La Plata Basin using different model parameterizations. In this work we used the Regional Climate Model (RegCM4) over CORDEX South America Domain. The model results were compared against Era-Interim analysis and CRU data. The results show that the low level jet representation is tied to both the precipitation convection scheme and the land-surface scheme. Several combinations of both convection and land-surface scheme have been tested and this can result in a weaker or stronger representation of the jet. The optimal configuration has been obtained and the physical explanation is presented. The jet position and strength is clearly influencing the precipitation spatial distribution and intensity over La Plata basin and by modeling the correct position and intensity the jet the dry bias over this basin is reduced.

  14. Mast fruiting is a frequent strategy in woody species of eastern South America.

    Directory of Open Access Journals (Sweden)

    Natalia Norden

    Full Text Available BACKGROUND: It is thought that mast seeding is a rare reproductive strategy in the tropics, since tropical climates are less variable, and fruit consumers tend to be more generalist in these regions. However, previous tests of this hypothesis were based on only few tropical datasets, and none from tropical South America. Moreover, reproductive strategies have been quantified based on the coefficient of variation of interannual seed production, an index that potentially confounds masting and high interannual variability in seed production. METHODOLOGY/PRINCIPAL FINDINGS: We developed a new approach to model the monthly variability in seed production for 28 tree species, and 20 liana species monitored during 5 years in a tropical forest of Central French Guiana. We found that 23% of the species showed a masting pattern, 54% an annual fruiting pattern, and 23% an irregular fruiting pattern. The majority of masting species were trees (8 out of 11, most of them animal-dispersed. The classification into reproductive strategies based on the coefficient of variation was inconsistent with our results in nearly half of the cases. CONCLUSIONS/SIGNIFICANCE: Our study is the first to clearly evidence the frequency of the masting strategy in a tropical forest community of Eastern South America. The commonness of the masting strategy in tropical plants may promote species coexistence through storage dynamics.

  15. A diplodocid sauropod survivor from the early cretaceous of South America.

    Directory of Open Access Journals (Sweden)

    Pablo A Gallina

    Full Text Available Diplodocids are by far the most emblematic sauropod dinosaurs. They are part of Diplodocoidea, a vast clade whose other members are well-known from Jurassic and Cretaceous strata in Africa, Europe, North and South America. However, Diplodocids were never certainly recognized from the Cretaceous or in any other southern land mass besides Africa. Here we report a new sauropod, Leikupal laticauda gen. et sp. nov., from the early Lower Cretaceous (Bajada Colorada Formation of Neuquén Province, Patagonia, Argentina. This taxon differs from any other sauropod by the presence of anterior caudal transverse process extremely developed with lateroventral expansions reinforced by robust dorsal and ventral bars, very robust centroprezygapophyseal lamina in anterior caudal vertebra and paired pneumatic fossae on the postzygapophyses in anterior-most caudal vertebra. The phylogenetic analyses support its position not only within Diplodocidae but also as a member of Diplodocinae, clustering together with the African form Tornieria, pushing the origin of Diplodocoidea to the Middle Jurassic or even earlier. The new discovery represents the first record of a diplodocid for South America and the stratigraphically youngest record of this clade anywhere.

  16. Environmental and Human Controls of Ecosystem Functional Diversity in Temperate South America

    Directory of Open Access Journals (Sweden)

    Domingo Alcaraz-Segura

    2013-01-01

    Full Text Available The regional controls of biodiversity patterns have been traditionally evaluated using structural and compositional components at the species level, but evaluation of the functional component at the ecosystem level is still scarce. During the last decades, the role of ecosystem functioning in management and conservation has increased. Our aim was to use satellite-derived Ecosystem Functional Types (EFTs, patches of the land-surface with similar carbon gain dynamics to characterize the regional patterns of ecosystem functional diversity and to evaluate the environmental and human controls that determine EFT richness across natural and human-modified systems in temperate South America. The EFT identification was based on three descriptors of carbon gain dynamics derived from seasonal curves of the MODIS Enhanced Vegetation Index (EVI: annual mean (surrogate of primary production, seasonal coefficient of variation (indicator of seasonality and date of maximum EVI (descriptor of phenology. As observed for species richness in the southern hemisphere, water availability, not energy, emerged as the main climatic driver of EFT richness in natural areas of temperate South America. In anthropogenic areas, the role of both water and energy decreased and increasing human intervention increased richness at low levels of human influence, but decreased richness at high levels of human influence.

  17. Meteotsunamis Occurring Along the Southwest Coast of South America During an Intense Storm

    Science.gov (United States)

    Carvajal, Matías; Contreras-López, Manuel; Winckler, Patricio; Sepúlveda, Ignacio

    2017-08-01

    In this paper, we report meteotsunamis occurring along the Chilean and Peruvian coasts. These atmospherically induced tsunami-like oscillations were instrumentally recorded during an intense storm that affected central Chile on August 8th, 2015. The storm was characterized by strong winds, a locally unprecedented atmospheric low pressure and intense sea-level oscillations which caused six casualties and severe damage to infrastructure along 500 km of coastline. The meteotsunamis are analyzed on both regional and local scales. On the regional scale, the temporal behavior and spatial behavior were discussed from the analysis of various tide gauges covering roughly 3000 km of the southwest coast of South America, between Callao, in central Peru, and Lebu, in southern Chile. Surprisingly, the phenomenon was recorded in the majority of the tide gauges in this vast region. On the area constrained by the storm region, a more detailed analysis is performed. We confirm the atmospheric origin of these intense sea-level oscillations by further analyzing meteorological records of air pressure and wind. An attempt to explain local (shelf and harbor) resonant mechanisms is achieved by means of wavelet analysis, while Greenspan and Proudman resonance mechanisms are superficially analyzed. Our results indicate that large meteotsunamis can occur along the west coast of South America and, when combined with other meteooceanographic conditions, may cause damage levels comparable to those resulting from Mw >8 earthquake generated tsunamis.

  18. Moisture sources to the 2010-2012 anomalous wet season in northern South America

    Science.gov (United States)

    Arias, Paola A.; Martínez, J. Alejandro; Vieira, Sara C.

    2015-11-01

    During 2010-2012, northern South America experienced one of the strongest wet seasons during the recent decades, with socio-economic implications of wide proportions. This period was characterized by two stronger-than-average La Niña events, one occurred in 2010-2011 and another less intense event in 2011-2012. This study focused on identifying the main moisture sources, besides the eastern Pacific, for the anomalous wet season occurred in this region during 2010-2012, and their association with the La Niña events observed in the equatorial Pacific. The results discussed here suggest that the main moisture sources to this anomalous wet season were the Pacific Ocean (via the westerly flow of the Choco jet) and the Caribbean Sea (via the weakening of the Caribbean low-level jet and the development of southward anomalies toward northern South America). Such changes appear to be associated not only to El Niño-Southern Oscillation (ENSO)-driven sea surface temperature anomalies in the eastern Pacific, Caribbean Sea, and north Atlantic, but also to ENSO-independent variability in the Atlantic Ocean. The latter is related to an enhanced Atlantic Meridional Mode.

  19. Cultural phylogenetics of the Tupi language family in lowland South America.

    Science.gov (United States)

    Walker, Robert S; Wichmann, Søren; Mailund, Thomas; Atkisson, Curtis J

    2012-01-01

    Recent advances in automated assessment of basic vocabulary lists allow the construction of linguistic phylogenies useful for tracing dynamics of human population expansions, reconstructing ancestral cultures, and modeling transition rates of cultural traits over time. Here we investigate the Tupi expansion, a widely-dispersed language family in lowland South America, with a distance-based phylogeny based on 40-word vocabulary lists from 48 languages. We coded 11 cultural traits across the diverse Tupi family including traditional warfare patterns, post-marital residence, corporate structure, community size, paternity beliefs, sibling terminology, presence of canoes, tattooing, shamanism, men's houses, and lip plugs. The linguistic phylogeny supports a Tupi homeland in west-central Brazil with subsequent major expansions across much of lowland South America. Consistently, ancestral reconstructions of cultural traits over the linguistic phylogeny suggest that social complexity has tended to decline through time, most notably in the independent emergence of several nomadic hunter-gatherer societies. Estimated rates of cultural change across the Tupi expansion are on the order of only a few changes per 10,000 years, in accord with previous cultural phylogenetic results in other language families around the world, and indicate a conservative nature to much of human culture.

  20. Climate and humans set the place and time of Proboscidean extinction in late Quaternary of South America

    DEFF Research Database (Denmark)

    Lima-Ribeiro, Matheus Souza; Nogues, David Bravo; Terribile, Levi Carina

    2013-01-01

    (ENMs) and modeled the timing for extinction under human hunting scenario, and both variables were used to explain the extinction dynamics of Proboscideans during a full interglacial/glacial cycle (from 126 ka to 6 ka) in South America. We found a large contraction in the geographic range size of two...... Proboscidean species studied (Cuvieronius hyodon and Notiomastodon platensis) across time. The largest contractions of their geographical ranges occurred in the northern part of South America, where we previously reported no evidence of coexistence among earliest humans and non-sloth megafauna, including...... on scattered patches of suitable habitats (i.e., refugia) around 11 ka, period in which the earliest humans potentially arrived in South America, increasing the population density thereafter. Under this overall unsuitable climatic condition at 11 ka, both Proboscideans would be extinct after around 550 years...

  1. Geographically Sourcing Cocaine’s Origin – Delineation of the Nineteen Major Coca Growing Regions in South America

    Science.gov (United States)

    Mallette, Jennifer R.; Casale, John F.; Jordan, James; Morello, David R.; Beyer, Paul M.

    2016-01-01

    Previously, geo-sourcing to five major coca growing regions within South America was accomplished. However, the expansion of coca cultivation throughout South America made sub-regional origin determinations increasingly difficult. The former methodology was recently enhanced with additional stable isotope analyses (2H and 18O) to fully characterize cocaine due to the varying environmental conditions in which the coca was grown. An improved data analysis method was implemented with the combination of machine learning and multivariate statistical analysis methods to provide further partitioning between growing regions. Here, we show how the combination of trace cocaine alkaloids, stable isotopes, and multivariate statistical analyses can be used to classify illicit cocaine as originating from one of 19 growing regions within South America. The data obtained through this approach can be used to describe current coca cultivation and production trends, highlight trafficking routes, as well as identify new coca growing regions. PMID:27006288

  2. Origin of samples of Cannabis sativa through insect fragments associated with compacted hemp drug in South America

    Directory of Open Access Journals (Sweden)

    Marcos Patrício Macedo

    2013-06-01

    Full Text Available Origin of samples of Cannabis sativa through insect fragments associated with compacted hemp drug in South America. Insects associated with a seizure of Cannabis sativa L. may indicate the origin of the illicit drug. Nevertheless, no work regarding this subject has been previously published for South America. In the present investigation, seven kilograms of vegetal material (C. sativa were inspected for insect fragments. Three species were identified and used to test the origin of the seizure of cannabis plant material: Euschistus heros (Fabricius, 1794, Thyanta perditor (Fabricius, 1794 (Heteroptera, Pentatomidae, and Cephalotes pusillus (Klug, 1824 (Hymenoptera, Formicidae. These insect species restricted the geographic origin of the drug to the Neotropical region, and their distribution patterns showed an overlap of the State of Mato Grosso (Brazil, Argentina, and Paraguay. Based on this information, two of the three major C. sativa growing areas in South America were excluded: (1 the Colombian territory and (2 northeastern Brazil.

  3. Climate co-variability between South America and Southern Africa at interannual, intraseasonal and synoptic scales

    Science.gov (United States)

    Puaud, Yohan; Pohl, Benjamin; Fauchereau, Nicolas; Macron, Clémence; Beltrando, Gérard

    2016-08-01

    This paper investigates and quantifies co-variability between large-scale convection in the South American and Southern African sectors at different timescales (interannual, intraseasonal and synoptic), during the austral summer seasons (November-February) from 1979 to 2012. Multivariate analyses (Canonical Correlation Analysis and Principal Component Analysis) are applied to daily outgoing longwave radiation (OLR, used as a proxy for atmospheric convection) anomalies to extract the principal modes of variability and co-variability in each and between both regions, filtered to consider the appropriate time-scales. At the interannual timescale, results confirm the predominant role of El Niño Southern Oscillation (ENSO), favoring enhanced convection over both southeastern Brazil and northern Argentina on the one hand, and tropical Africa and the western Indian Ocean on the other hand. At the intraseasonal timescale, the leading mode of co-variability is related to modulations of large-scale atmospheric convection over most of South America, and 10 days later, tropical Southern Africa. This mode accounts for the impacts of the Madden-Julian-oscillation (MJO) over these regions: identifying robust co-variability at the intraseasonal timescale between both regions require thus to consider a temporal shift between the two sectors. At the synoptic scale, however, co-variability consists mostly of a synchronous modulation of the large-scale atmospheric convection over the South American and Southern African sectors. This results from the development of concomitant Rossby waves forming a continuous wave train over the South Atlantic in the mid-latitudes, affecting both the South Atlantic and South Indian Convergence Zones. Among the days when convection shows significant anomalies (30 % of the total days in each sector), this synchronous mode occurs about 25 % of the time, individual Rossby waves modulating convection over one single region only during the remaining 75

  4. Weather and seasonal climate prediction for South America using a multi-model superensemble

    Science.gov (United States)

    Chaves, Rosane R.; Ross, Robert S.; Krishnamurti, T. N.

    2005-11-01

    This work examines the feasibility of weather and seasonal climate predictions for South America using the multi-model synthetic superensemble approach for climate, and the multi-model conventional superensemble approach for numerical weather prediction, both developed at Florida State University (FSU). The effect on seasonal climate forecasts of the number of models used in the synthetic superensemble is investigated. It is shown that the synthetic superensemble approach for climate and the conventional superensemble approach for numerical weather prediction can reduce the errors over South America in seasonal climate prediction and numerical weather prediction.For climate prediction, a suite of 13 models is used. The forecast lead-time is 1 month for the climate forecasts, which consist of precipitation and surface temperature forecasts. The multi-model ensemble is comprised of four versions of the FSU-Coupled Ocean-Atmosphere Model, seven models from the Development of a European Multi-model Ensemble System for Seasonal to Interannual Prediction (DEMETER), a version of the Community Climate Model (CCM3), and a version of the predictive Ocean Atmosphere Model for Australia (POAMA). The results show that conditions over South America are appropriately simulated by the Florida State University Synthetic Superensemble (FSUSSE) in comparison to observations and that the skill of this approach increases with the use of additional models in the ensemble. When compared to observations, the forecasts are generally better than those from both a single climate model and the multi-model ensemble mean, for the variables tested in this study.For numerical weather prediction, the conventional Florida State University Superensemble (FSUSE) is used to predict the mass and motion fields over South America. Predictions of mean sea level pressure, 500 hPa geopotential height, and 850 hPa wind are made with a multi-model superensemble comprised of six global models for the period

  5. TRMM precipitation analysis of extreme storms in South America: Bias and climatological contribution

    Science.gov (United States)

    Rasmussen, K. L.; Houze, R.; Zuluaga, M. D.; Choi, S. L.; Chaplin, M.

    2013-12-01

    The TRMM (Tropical Rainfall Measuring Mission) satellite was designed both to measure spatial and temporal variation of tropical rainfall around the globe and to understand the factors controlling the precipitation. TRMM observations have led to the realization that storms just east of the Andes in southeastern South America are among the most intense deep convection in the world. For a complete perspective of the impact of intense precipitation systems on the hydrologic cycle in South America, it is necessary to assess the contribution from various forms of extreme storms to the climatological rainfall. However, recent studies have suggested that the TRMM Precipitation Radar (PR) algorithm significantly underestimates surface rainfall in deep convection over land. Prior to investigating the climatological behavior, this research first investigates the range of the rain bias in storms containing four different types of extreme radar echoes: deep convective cores, deep and wide convective cores, wide convective cores, and broad stratiform regions over South America. The TRMM PR algorithm exhibits bias in all four extreme echo types considered here when the algorithm rates are compared to a range of conventional Z-R relations. Storms with deep convective cores, defined as high reflectivity echo volumes that extend above 10 km in altitude, show the greatest underestimation, and the bias is unrelated to their echo top height. The bias in wide convective cores, defined as high reflectivity echo volumes that extend horizontally over 1,000 km2, relates to the echo top, indicating that storms with significant mixed phase and ice hydrometeors are similarly affected by assumptions in the TRMM PR algorithm. The subtropical region tends to have more intense precipitating systems than the tropics, but the relationship between the TRMM PR rain bias and storm type is the same regardless of the climatological regime. The most extreme storms are typically not collocated with

  6. First detection of Mycobacterium ulcerans DNA in environmental samples from South America.

    Directory of Open Access Journals (Sweden)

    Aaron Morris

    Full Text Available The occurrences of many environmentally-persistent and zoonotic infections are driven by ecosystem changes, which in turn are underpinned by land-use modifications that alter the governance of pathogen, biodiversity and human interactions. Our current understanding of these ecological changes on disease emergence however remains limited. Buruli ulcer is an emerging human skin disease caused by the mycobacterium, Mycobacterium ulcerans, for which the exact route of infection remains unclear. It can have a devastating impact on its human host, causing extensive necrosis of the skin and underlying tissue, often leading to permanent disability. The mycobacterium is associated with tropical aquatic environments and incidences of the disease are significantly higher on floodplains and where there is an increase of human aquatic activities. Although the disease has been previously diagnosed in South America, until now the presence of M. ulcerans DNA in the wild has only been identified in Australia where there have been significant outbreaks and in western and central regions of Africa where the disease is persistent. Here for the first time, we have identified the presence of the aetiological agent's DNA in environmental samples from South America. The DNA was positively identified using Real-time Polymerase Chain Reaction (PCR on 163 environmental samples, taken from 23 freshwater bodies in French Guiana (Southern America, using primers for both IS2404 and for the ketoreductase-B domain of the M. ulcerans mycolactone polyketide synthase genes (KR. Five samples out of 163 were positive for both primers from three different water bodies. A further nine sites had low levels of IS2404 close to a standard CT of 35 and could potentially harbour M. ulcerans. The majority of our positive samples (8/14 came from filtered water. These results also reveal the Sinnamary River as a potential source of infection to humans.

  7. First detection of Mycobacterium ulcerans DNA in environmental samples from South America.

    Science.gov (United States)

    Morris, Aaron; Gozlan, Rodolphe; Marion, Estelle; Marsollier, Laurent; Andreou, Demetra; Sanhueza, Daniel; Ruffine, Rolland; Couppié, Pierre; Guégan, Jean-François

    2014-01-01

    The occurrences of many environmentally-persistent and zoonotic infections are driven by ecosystem changes, which in turn are underpinned by land-use modifications that alter the governance of pathogen, biodiversity and human interactions. Our current understanding of these ecological changes on disease emergence however remains limited. Buruli ulcer is an emerging human skin disease caused by the mycobacterium, Mycobacterium ulcerans, for which the exact route of infection remains unclear. It can have a devastating impact on its human host, causing extensive necrosis of the skin and underlying tissue, often leading to permanent disability. The mycobacterium is associated with tropical aquatic environments and incidences of the disease are significantly higher on floodplains and where there is an increase of human aquatic activities. Although the disease has been previously diagnosed in South America, until now the presence of M. ulcerans DNA in the wild has only been identified in Australia where there have been significant outbreaks and in western and central regions of Africa where the disease is persistent. Here for the first time, we have identified the presence of the aetiological agent's DNA in environmental samples from South America. The DNA was positively identified using Real-time Polymerase Chain Reaction (PCR) on 163 environmental samples, taken from 23 freshwater bodies in French Guiana (Southern America), using primers for both IS2404 and for the ketoreductase-B domain of the M. ulcerans mycolactone polyketide synthase genes (KR). Five samples out of 163 were positive for both primers from three different water bodies. A further nine sites had low levels of IS2404 close to a standard CT of 35 and could potentially harbour M. ulcerans. The majority of our positive samples (8/14) came from filtered water. These results also reveal the Sinnamary River as a potential source of infection to humans.

  8. THE RELATIONS OF THE NORTH AMERICAN FLORA TO THAT OF SOUTH AMERICA.

    Science.gov (United States)

    Bray, W L

    1900-11-09

    Reviewing the floral relations of North and South America as illustrated in the foregoing instances, we may say that the phenomena of distribution agree fairly with the record of physical conditions which have succeeded each other and those which still exist, and upon which we might almost a priori have predicted an analogous set of distribution phenomena. In this relationship we may distinguish three categories of distribution: (1) Those due to the conditions of human civilization, commerce, etc. This has resulted in placing the same species in similar regions of both continents, as, for example, Fagonia cretica in Lower California and Chile; Munroa squarrosa, western plains of North America, plains of Argentine and high plateaus of Chile and Bolivia; Frankenia grandiflora, Southern California and Arizona, coast lands of Chile; Oxytheca dendroidea, Lastarricea chilensis, and Chorizanthe comrnmissuralis, all in Southern California and Western Chile. (2) Those due to the operation of natural causes acting unde present conditions of climate, geology, etc. Under this head may be cited such species as sida leprosa, hastata, anomala, Cienfugosia sulphurea, Spergulariaplattensis and, in general, elements of Gulf zone distribution; also certain elements which still find a pathway along the continental axis, including some alpine and mountain xerophilous genera. (3) The third category of distribution would include those phenomena due to geological and climatic changes acting through long periods. Under this head are included the elements of greatest significance in the relationsip of the North and South America floras. The endemic boreal flora of the Andes, the equally endemic boreal flora of the Mexican Cordilleras, and genera with sharply distinct species or sub-genera in the arid extra-tropical regions of both continents, which may be called remnant elements.

  9. The New ILP Database of Quaternary Faults and Folds in South America

    Science.gov (United States)

    Costa, C. H.; Cisneros, H. A.; Machette, M. N.; Dart, R. L.

    2003-12-01

    As part of the International Lithosphere Program's Task Group II-2, we have completed the compilation of Quaternary faults and folds in South America and have established an Internet website for this data. The underpinning maps and reports have been released as electronic U.S. Geological Survey Open-File Reports (pdfs, see poster). The maps show the location, time, sense of slip, and activity rate of major earthquake-related features such as faults and fault-related folds. The maps are accompanied by descriptions of their Quaternary activity. The primary elements of the 10-year project are supervision and interpretation of geologic/tectonic information (Costa and Machette), data compilation (project participants), database design and management (Cisneros), and GIS input and management (Dart). A dozen experts in Quaternary faulting, neotectonics, paleoseismology, and seismology compiled the data: questions about individual faults or additions to the database should be directed to them. Prior to this project, digital maps of Quaternary faults did not exist for any of the South America countries, even though understanding the extent and character of active and older Quaternary faults are critical elements of seismic-hazards analysis. These new data will help extend the relatively short record of instrumental and felt seismicity that is the primary parameter for current seismic-hazard assessments in South American countries. Although some fault data were available for most of the countries (i.e., Venezuela), the degree of completeness varies as a function of the remoteness and vegetation cover (i.e., Brazil). A few faults such as the Bocono have had detailed investigations involving modern paleoseismic techniques. Other faults have been studied in some detail, usually in association with concerns about hazards to urban areas or the safety of critical facilities such as mining operations, oil-and-gas pipelines, or power-generating facilities. However, the general state

  10. Psychiatric hospital beds and prison populations in South America since 1990: does the Penrose hypothesis apply?

    Science.gov (United States)

    Mundt, Adrian P; Chow, Winnie S; Arduino, Margarita; Barrionuevo, Hugo; Fritsch, Rosemarie; Girala, Nestor; Minoletti, Alberto; Mitkiewicz, Flávia; Rivera, Guillermo; Tavares, María; Priebe, Stefan

    2015-02-01

    In 1939, English mathematician, geneticist, and psychiatrist Lionel Sharples Penrose hypothesized that the numbers of psychiatric hospital beds and the sizes of prison populations were inversely related; 75 years later, the question arises as to whether the hypothesis applies to recent developments in South America. To explore the possible association of changes in the numbers of psychiatric hospital beds with changes in the sizes of prison populations in South America since 1990. We searched primary sources for the numbers of psychiatric hospital beds in South American countries since 1990 (the year that the Latin American countries signed the Caracas Declaration) and compared these changes against the sizes of prison populations. The associations between the numbers of psychiatric beds and the sizes of prison populations were tested using fixed-effects regression of panel data. Economic variables were considered as covariates. Sufficiently reliable and complete data were obtained from 6 countries: Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay. The numbers of psychiatric beds and the sizes of prison populations. Since 1990, the numbers of psychiatric beds decreased in all 6 countries (ranging from -2.0% to -71.9%), while the sizes of prison populations increased substantially (ranging from 16.1% to 273.0%). Panel data regression analysis across the 6 countries showed a significant inverse relationship between numbers of psychiatric beds and sizes of prison populations. On average, the removal of 1 bed was associated with 5.18 more prisoners (95% CI, 3.10-7.26; P = .001), which was reduced to 2.78 prisoners (95% CI, 2.59-2.97; P beds and the sizes of prison populations remained practically unchanged when income inequality was considered as a covariate (-4.28 [95% CI, -5.21 to -3.36]; P beds have substantially decreased in South America, while the sizes of the prison populations have increased against a background of strong economic growth. The

  11. Avian influenza in North and South America, the Caribbean, and Australia, 2006-2008.

    Science.gov (United States)

    Senne, Dennis A

    2010-03-01

    Between 2006 and 2008, only one outbreak of highly pathogenic notifiable avian influenza (AI) was reported from the Americas, the Caribbean, and Australia. The outbreak, caused by H7N3, occurred in September 2007 in a multiage broiler breeder facility (approximately 49,000 birds) near Regina Beach in southern Saskatchewan, Canada. The disease was confined to a single farm; the farm was depopulated. All other reports of infections in poultry or wild birds involved low pathogenicity AI viruses. A notable event that occurred during the 3-yr period was the spread of low pathogenicity notifiable AI (LPNAI) H5N2 (Mexican lineage) into the Caribbean countries of the Dominican Republic and Haiti in 2007 and 2008, respectively, representing the first detection of AI reported in these countries. Mexico reported that the LPNAI H5N2 virus continued to circulate in the central regions of the country, and a total of 49 isolations were made from 12 states between 2006 and 2008. Also, during this period there was a significant increase in AI surveillance in many countries throughout the Americas, the Caribbean, and Australia, resulting in the detection of AI subtypes H1 through H12 and N1 through N9 in domestic bird species (chickens, turkeys, guinea fowl, upland game birds, and ducks/geese). The United States was the only one of these countries that reported detections of LPNAI (H5 or H7) infections in commercial poultry: one in chickens (H7N3, 2007), two in turkeys (H5N1 and H5N2, 2007), and one in pheasants (H5N8, 2008). Detections of AI viruses in wild birds between 2006 and 2008 were reported from North America (Canada and the United States), South America (Bolivia, Argentina, Chile, and Brazil), and Australia.

  12. Flavor precursors and sensory-active sulfur compounds in alliaceae species native to South Africa and South America.

    Science.gov (United States)

    Kubec, Roman; Krejčová, Petra; Mansur, Leví; García, Nicolás

    2013-02-13

    Profiles of S-substituted cysteine flavor precursors were determined in 42 Alliaceae species native to South Africa and South America. It was found that the pool of cysteine derivatives present in these plants is remarkably very simple, with S-((methylthio)methyl)cysteine 4-oxide (marasmin) being the principal flavor precursor, typically accounting for 93-100% of the pool. Out of the other cysteine derivatives, only minor quantities of methiin were present in some species. The marasmin-derived thiosulfinate marasmicin (2,4,5,7-tetrathiaoctane 4-oxide), a major sensory-active compound of the freshly disrupted plants, was isolated, and its organoleptic properties were evaluated. Furthermore, sulfur-containing volatiles formed upon boiling of these alliaceous species were studied by GC-MS. The profile of the volatiles formed was relatively simple, with 2,3,5-trithiahexane and 2,4,5,7-tetrathiaoctane being the major components. Despite the traditional belief, ingestion of the marasmin-rich plants was always accompanied by development of a strong "garlic breath". We believe that especially several Tulbaghia species deserve to attract much greater attention from the food industry thanks to their pungent garlicky taste and unusual yet pleasant alliaceous smell.

  13. Subduction-controlled mantle flow and seismic anisotropy in South America

    Science.gov (United States)

    Hu, Jiashun; Faccenda, Manuele; Liu, Lijun

    2017-07-01

    Seismic anisotropy records both the past and present deformation inside the solid Earth. In the mantle, seismic anisotropy is mainly attributed to the lattice preferred orientation (LPO) of mineral fabrics, caused by the shear deformation due to mantle flow. However, contributions from different tectonic processes remain debated, and a single geodynamic model that simultaneously explains the observed mantle structures and various seismic anisotropy measurements is still lacking. Here, we present a model for the Cenozoic subduction history in South America using a geodynamic simulation constrained by both past plate reconstructions and present mantle seismic structures. With a recently developed software package DRexS, we further predict azimuthal seismic anisotropy at different depths and generate synthetic shear wave splitting (SWS) measurements using the resulting mantle flow. Our results provide a good match to both depth-dependent surface wave anisotropy and various land-based SWS records. We find that the dominant control on seismic anisotropy in South America comes from subduction-induced mantle flow, where anisotropy below the subducting Nazca Plate aligns with plate-motion-induced Couette flow and that below the overriding South American Plate follows slab-induced Poiseuille flow. This large-scale mantle flow can be diverted by secondary slabs, such as that below the Antilles subduction zone. In contrast, the contribution to SWS from fossil continental anisotropy and from the effects due to mantle flow modulation by lithosphere thickness variation are minor. Upper-mantle fast seismic anomalies beneath the southern Atlantic margin should have close-to-neutral buoyancy in order to satisfy the observed seismic anisotropy.

  14. Fault Plane Orientations of Intermediate-Depth Earthquakes in South America

    Science.gov (United States)

    Warren, L. M.

    2013-12-01

    Extending from Colombia in the north to Chile and Argentina in the south, the South American subduction zone exhibits considerable variation: the subduction angle alternates between flat and steep; the subducting plate has complex structures such as ridges, plateaus, and fracture zones; and late Cenozoic volcanism in the overlying plate has gaps. I investigate the effect of these differences in incoming plate structure and subduction geometry on intermediate-depth earthquakes and use the results to test hypotheses for why intermediate-depth earthquakes occur. For all large (Mw ≥5.7) intermediate-depth earthquakes (60-360 km depth) in South America since 1990, I analyze rupture directivity to try to distinguish which of the two possible fault planes of the focal mechanism slipped in the earthquake. Of the 163 earthquakes that met the selection criteria, half were recorded with a sufficient distribution of stations to determine if there was directivity to the rupture and fault planes were identified for 31 events. Fault plane orientations are spatially coherent. In regions with "normal" subduction angles, such as the Central Volcanic Zone (southern Peru to central Chile), results are consistent with previous studies in Central America and the western Pacific subduction zones: most earthquakes rupture along subhorizontal faults and rupture azimuths are randomly distributed. In the Peruvian Flat Slab, identified fault planes dip eastward. After taking into account the angle of subduction, these faults are perpendicular to the faults that rupture in regions with normal subduction angles. Within sharply curved slab segments, such as the rebending of the plate at the eastern edge of the Peruvian flat slab, both orientations of faults slip. The observed flip in dominant fault plane orientation on either side of sharply curved slab segments suggests that bending and unbending stresses have an important role in controlling fault orientations. Pre-existing weak zones may

  15. First record of the family Pseudochiridiidae (Arachnida, Pseudoscorpiones) from continental South America--a Pseudochiridium from a Brazilian cave.

    Science.gov (United States)

    Von Schimonsky, Diego Monteiro; Bichuette, Maria Elina; Mahnert, Volker

    2014-12-02

    The small pseudoscorpion family Pseudochiridiidae Chamberlin, 1923 comprises two genera and 12 extant species recorded from Asia (Burma, Christmas Island, Indonesia, India, Nepal, Malaysia, New Guinea, Philippines, Nicobars and Sumba), eastern, central and southern Africa (Chad, D.R. Congo, Kenya, South Africa, Tanzania), Madagascar, Seychelles (Aldabra), North America (Florida) and the Caribbean Islands of Dominican Republic and Cuba (Harvey 2013, Barba & Barroso 2013); one unidentified species is mentioned for the fauna of Mexico (Ceballos 2004). A fossil species has been described from Dominican amber by Judson (2007), who predicted the presence of this family in South America

  16. Shaping the Future: Asia-Pacific and Latin America-Caribbean Cooperation: ADB and IDB Partnership for South-South Cooperation

    OpenAIRE

    2012-01-01

    Cooperation between Asia and Latin America and the Caribbean (LAC) is rapidly increasing in the spirit of South-South cooperation. The Asian Development Bank (ADB) and the Inter-American Development Bank (IDB) enter into a new chapter of cooperation in areas such as sustainable integration corridors (trade facilitation, transportation, energy, and telecommunications, including broadband investment and regulation); sustainable cities and climate change; institutional development; social policy...

  17. The carbon balance of South America: a review of the status, decadal trends and main determinants

    Directory of Open Access Journals (Sweden)

    M. Gloor

    2012-12-01

    Full Text Available We summarise the contemporary carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric environment and climate. Component flux estimate methods we consider sufficiently reliable for this purpose encompass fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and agricultural export data. Alternative methods for the estimation of the continental-scale net land to atmosphere CO2 flux, such as atmospheric transport inverse modelling and terrestrial biosphere model predictions, are, we find, hampered by the data paucity, and improved parameterisation and validation exercises are required before reliable estimates can be obtained. From our analysis of available data, we suggest that South America was a net source to the atmosphere during the 1980s (~ 0.3–0.4 Pg C a−1 and close to neutral (~ 0.1 Pg C a−1 in the 1990s. During the latter period, carbon uptake in old-growth forests nearly compensated for the carbon release associated with fossil fuel burning and deforestation.

    Annual mean precipitation over tropical South America as inferred from Amazon River discharge shows a long-term upward trend. Although, over the last decade dry seasons have tended to be drier, with the years 2005 and 2010 in particular experiencing strong droughts. On the other hand, precipitation during the wet seasons also shows an increasing trend. Air temperatures have also increased slightly. Also with increases in atmospheric CO2 concentrations, it is currently unclear what effect these climate changes are having on the forest carbon balance of the region. Current indications are that the forests of the Amazon Basin have acted as a substantial long-term carbon sink, but with the most recent

  18. Quantification and visualization of the human impacts of anticipated precipitation extremes in South America

    Science.gov (United States)

    Fuller, C. T.; Sabesan, A.; Khan, S.; Kuhn, G.; Ganguly, A. R.; Erickson, D. J.; Ostrouchov, G.

    2006-12-01

    The research described here quantifies and visualizes the human impacts of extreme events, which in turn can lead to enhanced disaster readiness levels as well as response or mitigation strategies. Specifically, we investigate the space-time impact of anticipated precipitation extremes on human population in South America. The research attempts to integrate two recent and ongoing lines of research. In the first study (Sabesan et al., 2006; Abercrombie et al, 2006) LandScan® high-resolution population data sets were used to develop threat metrics in space and time. In the second study (Khan et al, 2006; Kuhn and Ganguly, 2006), grid-based observations of precipitation time series in South America were utilized to quantify the probability of precipitation extremes in space and time and define a geo-referenced "extremes volatility ratio" (EVR) for unanticipated, or the "truly unusual", extremes. Here we define an "extremes volatility index" (EVI) which scales from zero to unity and provides an anticipated measure of surprise corresponding to the truly unusual extremes. An EVI of zero indicates no possibility of surprise with the truly unusual extremes statistically identical to the "typical extremes", or the extremes considered, for example, in engineering design. We investigate the EVI in conjunction with maps for ambient population in South America obtained from a high- resolution global population database called LandScan® to produce a "human risk index" (HRI) in space and time. The EVI is roughly interpreted as a probability number which is multiplied with the population at each grid in space and time to obtain a measure of risk. Future research needs to explore measures of risk that consider other costs of disasters, for example impacts on critical infrastructures. A geo-referenced index, the "disaster impact index" (DII) is proposed. The DII at each grid is computed by dividing the HRI with the Gross Domestic Product (GDP) for each country. The GDP is utilized

  19. Strong plate coupling along the Nazca/South America convergent margin

    Science.gov (United States)

    Iaffaldano, G.; Bunge, H.

    2007-12-01

    The force balance in plate tectonics is fundamentally important, but poorly known. Much information on the dynamics is embedded in the record of past and present plate velocities, featured with long- as well as short- term variations, but a precise budget, in particular of resistive coupling forces along convergent margins, is hard to come by. Building on substantial, yet separate progress in modeling lithosphere dynamics and mantle convection, we couple global lithosphere models with high-resolution (more than 100 million grid points) 3-D circulation models of Earth's mantle and demonstrate that an accurate budget of plate boundary forces can be obtained. We prove the effectiveness of our approach by computing a detailed force budget along the Nazca/South America subduction zone, showing that a large portion of it comes from the recent uplift of the Andes. We find that forces computed with our global, coupled models provide simultaneous explanations for three seemingly unrelated key observations along the South American margin: (1) trench parallel gravity anomalies, (2) pronounced bathymetry variations, as well as (3) a substantial reduction in Nazca/South America plate convergence recorded over the past 10 million years. All these observations can be explained from along- trench, lateral and temporal variations in plate coupling forces that are predicted from our simulations. Interestingly enough, the distribution of great earthquakes such as the recent M 8.0 event of Peru coincides with moderate to low coupling between subducting and overriding plates. For the same convergent margin we also show that frictional forcing due to trench sediment infill is, by comparison, of minor importance. Finally, we provide an intriguing explanation for the peculiar convex shape of the South American margin. Paleomagnetic and geodetic data indicate substantial rotation over the past m.y. and continuing at present day. We tie the bend of the margin to variations in plate coupling

  20. Characterization of Trypanosoma rangeli Strains Isolated in Central and South America: an Overview

    Directory of Open Access Journals (Sweden)

    Grisard Edmundo C

    1999-01-01

    Full Text Available Trypanosoma rangeli is a hemoflagelate parasite that infects domestic and sylvatic animals, as well as man, in Central and South America. T. rangeli has an overlapping distribution with T. cruzi, the etiological agent of Chagas disease, sharing several animal reservoirs and triatomine vectors. We have isolated T. rangeli strains in the State of Santa Catarina, in southern Brazil, which dramatically increased the distribution area of this parasite. This brief review summarizes several studies comparing T. rangeli strains isolated in Santa Catarina with others isolated in Colombia, Honduras and Venezuela. The different methods used include indirect immunofluorescence and western blot assays, lectin agglutination, isoenzyme electrophoresis and random amplified polymorphic DNA analysis, triatomine susceptibility, in vitro cell infection assays, and mini-exon gene analysis.

  1. Satellite-based detection of volcanic sulphur dioxide from recent eruptions in Central and South America

    Directory of Open Access Journals (Sweden)

    D. Loyola

    2008-01-01

    Full Text Available Volcanic eruptions can emit large amounts of rock fragments and fine particles (ash into the atmosphere, as well as several gases, including sulphur dioxide (SO2. These ejecta and emissions are a major natural hazard, not only to the local population, but also to the infrastructure in the vicinity of volcanoes and to aviation. Here, we describe a methodology to retrieve quantitative information about volcanic SO2 plumes from satellite-borne measurements in the UV/Visible spectral range. The combination of a satellite-based SO2 detection scheme and a state-of-the-art 3D trajectory model enables us to confirm the volcanic origin of trace gas signals and to estimate the plume height and the effective emission height. This is demonstrated by case-studies for four selected volcanic eruptions in South and Central America, using the GOME, SCIAMACHY and GOME-2 instruments.

  2. First record of Perkinsus chesapeaki infecting Crassostrea rhizophorae in South America.

    Science.gov (United States)

    Dantas Neto, Maximiano Pinheiro; Gesteira, Tereza Cristina Vasconcelos; Sabry, Rachel Costa; Feijó, Rubens Galdino; Forte, Jamille Martins; Boehs, Guisla; Maggioni, Rodrigo

    2016-11-01

    This study investigated Perkinsus spp. infecting Crassostrea rhizophorae from the Jaguaribe River estuary, Ceará, Brazil. Fragments of gills and rectum of the oysters (n=150) were incubated in Ray's fluid thioglycollate medium (RFTM). Genus Perkinsus-specific PerkITS85/750 PCR assays were performed and their amplicons were sequenced by the Sanger method. The RFTM assays confirmed Perkinsus spp. The sequencing of the amplified fragments from the rDNA internal transcribed spacers (ITS) of Perkinsus spp. confirmed Perkinsus chesapeaki. Neighbor-Joining analyzes place P. chesapeaki identified in this study in a well-supported clade with other isolates of the same species. This is the first record of P. chesapeaki infecting C. rhizophorae in South America. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. LATTES: a new gamma-ray detector concept for South America

    Directory of Open Access Journals (Sweden)

    Assis P.

    2017-01-01

    Full Text Available Currently the detection of Very High Energy gamma-rays for astrophysics rely on the measurement of the Extensive Air Showers (EAS either using Cherenkov detectors or EAS arrays with larger field of views but also larger energy thresholds. In this talk we present a novel hybrid detector concept for a EAS array with an improved sensitivity in the lower energies (~ 100 GeV. We discuss its main features, capabilities and present preliminary results on its expected perfomances and sensitivities.This wide field of view experiment is planned to be installed at high altitude in South America making it a complementary project to the planned Cherenkov telescope experiments and a powerful tool to trigger further observations of variable sources and to detect transients phenomena.

  4. Obesity, Diabetes, and Other Cardiovascular Risk Factors in Native Populations of South America.

    Science.gov (United States)

    Ingaramo, Roberto A

    2016-01-01

    Cardiovascular disease remains the leading cause of death in both developed and developing countries. In South America, the native population comprises a great number of different ethnic groups. The cardiovascular risk factors observed in these groups have proved similar to and even higher than those found in general non-native populations. Relatively recent epidemiologic information reveals that many native communities have healthy habits with low prevalence of risk factors such as hypertension and diabetes, while their prevalence is higher in those who have kept close contact with non-native populations and have westernized their habits. The differences in the presence of risk factors in these populations have been explained as the result of several interacting factors including genetic to environmental, socioeconomic, and cultural causes.

  5. Pathology in skeletons of Peale's dolphin Lagenorhynchus australis from southern South America.

    Science.gov (United States)

    San Martín, Analía A; Macnie, Silvina V; Goodall, R Natalie P; Boy, Claudia C

    2016-06-15

    Peale's dolphin Lagenorhynchus australis is frequently seen off the coast of southern South America, where it feeds among coastal kelp beds and occasionally strands. We searched for macroscopic evidence of skeletal lesions in 78 specimens of Peale's dolphin from 2 museum collections, which contain almost all of the species' skeletons known in collections worldwide. Thirty-two specimens (41%) had some type of osteological abnormalities. In 21 cases (66%), congenital deformations were the most predominant abnormality found. Acquired lesions included (1) induced trauma: abnormal curvature (n=5 specimens) and fractures (n=2); (2) infectious diseases: spondylo-osteomyelitis (n=3); and (3) degenerative diseases: exostoses (n=8) and spondylosis deformans (n=4). It is noteworthy that all of these animals died incidentally in gillnet entanglement and were presumably healthy at the time of death. The effect that different osseous lesions may have on an animal's quality of life may depend on the area of the spine affected and the number of vertebrae involved.

  6. ITS-2 sequences-based identification of Trichogramma species in South America

    Directory of Open Access Journals (Sweden)

    R. P. Almeida

    Full Text Available Abstract ITS2 (Internal transcribed spacer 2 sequences have been used in systematic studies and proved to be useful in providing a reliable identification of Trichogramma species. DNAr sequences ranged in size from 379 to 632 bp. In eleven T. pretiosum lines Wolbachia-induced parthenogenesis was found for the first time. These thelytokous lines were collected in Peru (9, Colombia (1 and USA (1. A dichotomous key for species identification was built based on the size of the ITS2 PCR product and restriction analysis using three endonucleases (EcoRI, MseI and MaeI. This molecular technique was successfully used to distinguish among seventeen native/introduced Trichogramma species collected in South America.

  7. The first troglobitic species of freshwater flatworm of the suborder Continenticola (Platyhelminthes from South America

    Directory of Open Access Journals (Sweden)

    Stella Teles de Souza

    2015-01-01

    Full Text Available Brazilian cave diversity, especially of invertebrates, is poorly known. The Bodoquena Plateau, which is located in the Cerrado Biome in central Brazil, has approximately 200 recorded caves with a rich system of subterranean water resources and high troglobitic diversity. Herein we describe a new troglobitic species of Girardia that represents the first obligate cave-dwelling species of the suborder Continenticola in South America. Specimens of the new species, which occur in a limestone cave in the Bodoquena Plateau, in the Cerrado biome, are unpigmented and eyeless. Species recognition in the genus Girardia is difficult, due to their great morphological resemblance. However, the new species can be easily recognized by a unique feature in its copulatory apparatus, namely a large, branched bulbar cavity with multiple diverticula.

  8. Doses from 222Rn, 226Ra, and 228Ra in groundwater from Guarani aquifer, South America.

    Science.gov (United States)

    Bonotto, D M

    2004-01-01

    Groundwater samples were analysed for 222Rn, 226Ra, and 228Ra in Guarani aquifer spreading around 1 million km2 within four countries in South America, and it was found that their activity concentrations are lognormally distributed. Population-weighted average activity concentration for these radionuclides allowed to estimate a value either slightly higher (0.13 mSv/year) than 0.1 mSv for the total effective dose or two times higher (0.21 mSv/year) than this limit, depending on the choice of the dose conversion factor. Such calculation adds useful information for the appropriate management of this transboundary aquifer that is socially and economically very important to about 15 million inhabitants living in Brazil, Argentina, Uruguay and Paraguay.

  9. Early dispersals of maize and other food plants into the Southern Caribbean and Northeastern South America

    Science.gov (United States)

    Pagán-Jiménez, Jaime R.; Rodríguez-Ramos, Reniel; Reid, Basil A.; van den Bel, Martijn; Hofman, Corinne L.

    2015-09-01

    Grindstones from Eva 2 and St. John, two of the earliest sites in northeastern South America and the southern Caribbean respectively, were subjected to starch grain analysis. Results of this study revealed that these stone artifacts were utilized to process a variety of cultivars such as maize (Zea mays), sweet potato (Ipomoea batatas), chili pepper (Capsicum spp.), achira (Canna spp.), legumes (Fabaceae), and yams (Dioscoreaceae), coupled with wild resources, most notably marunguey (Zamia spp.). Radiocarbon dates indicate that the use of plants identified at these two sites were much older than previously considered, going back to at least 7790 cal. BP at St. John and 5990 cal. BP at Eva 2. This new evidence showcases the importance of the Caribbean basin as an arena for early phytocultural dispersals. It also focuses attention on the role of navigation as a mechanism for crop diffusion in the Neotropics.

  10. An overview of the nutritional value of beef and lamb meat from South America.

    Science.gov (United States)

    Cabrera, M C; Saadoun, A

    2014-11-01

    The southern region of South America, a subtropical and temperate zone, is an important region for the production of beef and lamb meat, which is mainly produced in extensive pasture-based systems. Because of its content in highly valuable nutrients such as iron, zinc, selenium, fatty acids, and vitamins, meat is a unique and necessary food for the human diet in order to secure a long and healthy life, without nutritional deficiencies. Beef and lamb production systems based on temperate or tropical grasslands show interesting and, in some cases, a differential content in minerals, fatty acids and vitamins. This review deals with the distinctive aspects of the nutritional quality of beef and lamb meat produced in this region in terms of nutritional composition and the bioavailability of key nutrients related to its contribution for a healthy diet for all ages.

  11. [Health, globalization and interculturalism: an anthropological approach to the situation of indigenous peoples in South America].

    Science.gov (United States)

    Hita, Susana Ramírez

    2014-10-01

    This article reflects upon the impact of globalization and interculturalism on the living conditions of indigenous peoples in South America. Through two examples - Bolivia and Argentina - it is seen how health interculturalism has transformed into a discourse and a practice that both global organizations and most Latin American countries have used to assimilate and attract indigenous communities. Traditional medicine is respected and valued without proposing changes to improve the living conditions of these population groups. This is especially true in those areas where land is being expropriated or contaminated with the extraction of gas, oil, minerals and the construction of dams, along with indiscriminate deforestation of the rainforest. Health/illness cannot be separated from the territorial conditions of these peoples since environmental health is critical for their survival.

  12. Revision of the genus Lolliguncula Steenstrup, 1881 (Cephalopoda: Loliginidae off the Pacific Coast of South America

    Directory of Open Access Journals (Sweden)

    Franz Cardoso

    2013-12-01

    Full Text Available In the present paper the species from the genus LolligunculaSteentrup, 1881 (Cephalopoda: Loliginidae in Southeastern Pacific Ocean are reviewed. The presence of Lolliguncula (Lolliguncula panamensisBerry, 1911, Lolliguncula (Loliolopsis diomedeae Hoyle, 1911 and Lolliguncula (Lolliguncula argusBrakoniecki and Roper, 1985 are confirmed from Mexican waters to Perú and the species Lolliguncula (Lolliguncula arguscollected during a cruise of the R/V Anton Bruunfrom 1966 off the coast of South America is recorded for the first time in Peruvian waters. A key to identification of Pacific species is given. We report a diagnostic feature with taxonomic remarks of these species. Updated information on the distribution, biology, and fisheries of each species also is discussed.

  13. Solid and aqueous mercury in remote river sediments (Litany River, French Guyana, South America)

    Science.gov (United States)

    Charlet, L.; Roman-Ross, G.; Spadini, L.; Rumbach, G.

    2003-05-01

    Mercury content in river sediments was investigated, in the Haut Maroni river basin (French Guyana, South America), around Antecume-Pata, a village where Wayanas Amerindians are contaminated with mercury. Solid sediment particulate total mercury content indicate a 100 to 150 ng/g Hg geochemical background level. Sediments act as an environmental archive: gold mining contaminated sediments have up to 400 ng/g total mercury. Pore waters from contaminated sediments are enriched in Fe(II) and Hg(II) by a factor 40 compared to uncontaminated sediment pore waters, due to more acute anoxie conditions. They act therefore as a major source of dissolved mercury in remote tropical aquatic ecosystems. Keywords: Mercury, sediment, DGT and DET techniques, pore water, gold mining.

  14. Integration processes in South America and the role of Brazil: the cases of Mercosur and Unasur

    Directory of Open Access Journals (Sweden)

    Miriam Gomes Saraiva

    2012-04-01

    Full Text Available The article examines the current state of the views of the political actors in integration processes in South America, and which represent the basis for the evolution of these processes. Using this perspective, the author analyses the recent history of Mercosur and Unasur. As a second objective, the article examines the role Brazil has played in the evolution of these two initiatives in recent years. To achieve these objectives, the author begins by presenting the opinions of the region’s political actors on regional integration, defined by means of common elements. The author then goes on to present the main characteristics of the recent evolution of Mercosur and Unasur. The third part analyze the role Brazil has played in this new scenario. Finally, the conclusion summarises the two initiatives and highlights the likely prospects for Dilma Rousseff’s government in relation to Brazil’s policy in the region.

  15. Checklist of helminths from lizards and amphisbaenians (Reptilia, Squamata of South America

    Directory of Open Access Journals (Sweden)

    RW Ávila

    2010-01-01

    Full Text Available A comprehensive and up to date summary of the literature on the helminth parasites of lizards and amphisbaenians from South America is herein presented. One-hundred eighteen lizard species from twelve countries were reported in the literature harboring a total of 155 helminth species, being none acanthocephalans, 15 cestodes, 20 trematodes and 111 nematodes. Of these, one record was from Chile and French Guiana, three from Colombia, three from Uruguay, eight from Bolivia, nine from Surinam, 13 from Paraguay, 12 from Venezuela, 27 from Ecuador, 17 from Argentina, 39 from Peru and 103 from Brazil. The present list provides host, geographical distribution (with the respective biome, when possible, site of infection and references from the parasites. A systematic parasite-host list is also provided.

  16. Geologic mapping and mineral resource inventory by ERTS-1 satellite data in South America

    Science.gov (United States)

    Carter, W. D. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. ERTS-1 data clearly provide significant contribution of new information on the remote areas of South America. Salar deposits have been measured and compared with those shown on World Navigation Charts; remarkable differences have been found in shape, size, number, and distribution. Repetitive coverage should enable us to develop an index of seasonal and annual environmental trends that can be compared with those of the Northern Hemisphere. New lineations, many of which are probably faults, have been found in Venezuela, Bolivia, and northern Argentina. Circular features, some of volcanic origin, have been recognized that are not shown on existing maps. The courses of several rivers have been revised and our Venezuelan counterparts report that a major new river has been recognized and charted. Large mining operations, such as the open pit copper mine of Chuquicamata in northern Chile, are recognizable and can be studied in their regional context.

  17. Record of the genus Aeolosaurus (Sauropoda, Titanosauria) in the Late Cretaceous of South America: paleogeographic implications

    Energy Technology Data Exchange (ETDEWEB)

    Candeiro, C.R.A.

    2010-07-01

    The Upper Cretaceous of South America has yielded fossils of the Aeolosaurini titanosaurian Aeolosaurus from Argentina (from the Allen, Los Alamitos, Angostura Colorada, and Bajo Barreal formations) and Brazil (Adamantina and Marilia formations). To date, four Aeolosaurus species have been recognized: Aeolosaurus colhuehuapensis, Aeolosaurus rionegrinus, A. rionegrinus? and Aeolosaurus sp. Gondwanatitan faustoi, recently considered a junior synonym of Aeolosaurus, is here demonstrated to be a valid taxon. The occurrence of Aeolosaurus in Turonian-Santonian rocks of central Brazil and in Campanian-Maastrichtian deposits of Argentina suggests that the temporal and geographic distribution of aeolosaurines was greater than previously recognized. The Aeolosaurus records from the Maastrichtian Marilia Formation of Brazil demonstrate that this genus persisted after the marine incursion that occurred in northern Patagonia during the Campanian-Maastrichtian. The Late Cretaceous tetrapod assemblages of central Brazil and Patagonia are comparable in age and fossil content. (Author).

  18. Multi-proxy palaeoclimate reconstructions from peatlands in southern South America

    Science.gov (United States)

    Roland, Thomas; Hughes, Paul; Mauquoy, Dmitri; van Bellen, Simon; Daley, Tim; Loader, Neil; Street-Perrott, Alayne

    2014-05-01

    There is a relative paucity of palaeoclimatic archives in South America relative to many other regions of the world. This paucity must be addressed in order to validate climate models and improve our understanding of the global climate system. The southern westerlies represent an important component of climatic variability in the region and, in turn, their migration and changes in their intensity can play a key role in determining whether the Southern Ocean functions as a sink or source of atmospheric carbon dioxide. Increased ventilation of deep waters with elevated concentrations of dissolved inorganic carbon, driven by enhanced Ekman transport, leads to increased outgassing of carbon dioxide. However, as instrumental records are limited to the latter half of the twentieth century, little is known about the long-term variability of the southern Westerlies and their subsequent effects. The Peninsula Brunswick and Isla Grande de Tierra del Fuego are directly situated in the core path of the southern westerlies during the Austral summer and they are ideally suited for studies of past variability in westerly intensity and position. The region's abundant peatlands are capable of recording these long-term changes, as wind intensity and westerly position affects precipitation and temperature, two key drivers (i.e. P-E) of water-table dynamics in ombrotrophic peatlands. Currently, the peatlands of southern Patagonia represent a relatively unexploited resource in terms of palaeoclimate reconstruction. As a result, we have developed a new regional network of multi-proxy (testate amoebae, plant macrofossils, stable isotopes) archives, supported by high-resolution radiocarbon chronologies, to develop quantitative climate reconstructions for southern South America spanning the last ~2000 years using Sphagnum magellanicum-dominated peat deposits.

  19. Agricultural impacts of glyphosate-resistant soybean cultivation in South America.

    Science.gov (United States)

    Cerdeira, Antonio L; Gazziero, Dionsio L P; Duke, Stephen O; Matallo, Marcus B

    2011-06-08

    In the 2009/2010 growing season, Brazil was the second largest world soybean producer, followed by Argentina. Glyphosate-resistant soybeans (GRS) are being cultivated in most of the soybean area in South America. Overall, the GRS system is beneficial to the environment when compared to conventional soybean. GRS resulted in a significant shift toward no-tillage practices in Brazil and Argentina, but weed resistance may reduce this trend. Probably the highest agricultural risk in adopting GRS in Brazil and South America is related to weed resistance due to use of glyphosate. Weed species in GRS fields have shifted in Brazil to those that can more successfully withstand glyphosate or to those that avoid the time of its application. Five weed species, in order of importance, Conyza bonariensis (L.) Cronquist, Conyza canadensis (L.) Cronquist, Lolium multiflorum Lam., Digitaria insularis (L.) Mez ex Ekman, and Euphorbia heterophylla L., have evolved resistance to glyphosate in GRS in Brazil. Conyza spp. are the most difficult to control. A glyphosate-resistant biotype of Sorghum halepense L. has evolved in GRS in Argentina and one of D. insularis in Paraguay. The following actions are proposed to minimize weed resistance problem: (a) rotation of GRS with conventional soybeans in order to rotate herbicide modes of action; (b) avoidance of lower than recommended glyphosate rates; (c) keeping soil covered with a crop or legume at intercrop intervals; (d) keeping machinery free of weed seeds; and (d) use of a preplant nonselective herbicide plus residuals to eliminate early weed interference with the crop and to minimize escapes from later applications of glyphosate due to natural resistance of older weeds and/or incomplete glyphosate coverage.

  20. Subduction zone locking, strain partitioning, intraplate deformation and their implications to Seismic Hazards in South America

    Science.gov (United States)

    Galgana, G. A.; Mahdyiar, M.; Shen-Tu, B.; Pontbriand, C. W.; Klein, E.; Wang, F.; Shabestari, K.; Yang, W.

    2014-12-01

    We analyze active crustal deformation in South America (SA) using published GPS observations and historic seismicity along the Nazca Trench and the active Ecuador-Colombia-Venezuela Plate boundary Zone. GPS-constrained kinematisc models that incorporate block and continuum techniques are used to assess patterns of regional tectonic deformation and its implications to seismic potential. We determine interplate coupling distributions, fault slip-rates, and intraplate crustal strain rates in combination with historic earthquakes within 40 seismic zones crust to provide moment rate constraints. Along the Nazca subduction zone, we resolve a series of highly coupled patches, interpreted as high-friction producing "asperities" beneath the coasts of Ecuador, Peru and Chile. These include areas responsible for the 2010 Mw 8.8 Maule Earthquake and the 2014 Mw 8.2 Iquique Earthquake. Predicted tectonic block motions and fault slip rates reveal that the northern part of South America deforms rapidly, with crustal fault slip rates as much as ~20 mm/a. Fault slip and locking patterns reveal that the Oca Ancón-Pilar-Boconó fault system plays a key role in absorbing most of the complex eastward and southward convergence patterns in northeastern Colombia and Venezuela, while the near-parallel system of faults in eastern Colombia and Ecuador absorb part of the transpressional motion due to the ~55 mm/a Nazca-SA plate convergence. These kinematic models, in combination with historic seismicity rates, provide moment deficit rates that reveal regions with high seismic potential, such as coastal Ecuador, Bucaramanga, Arica and Antofagasta. We eventually use the combined information from moment rates and fault coupling patterns to further constrain stochastic seismic hazard models of the region by implementing realistic trench rupture scenarios (see Mahdyiar et al., this volume).

  1. Risk for transfusion-transmitted infectious diseases in Central and South America.

    Science.gov (United States)

    Schmunis, G A; Zicker, F; Pinheiro, F; Brandling-Bennett, D

    1998-01-01

    We report the potential risk for an infectious disease through tainted transfusion in 10 countries of South and Central America in 1993 and in two countries of South America in 1994, as well as the cost of reagents as partial estimation of screening costs. Of the 12 countries included in the study, nine screened all donors for HIV; three screened all donors for hepatitis B virus (HBV); two screened all donors for Trypanosoma cruzi; none screened all donors for hepatitis C virus (HCV); and six screened some donors for syphilis. Estimates of the risk of acquiring HIV through blood transfusion were much lower than for acquiring HBV, HCV, or T. cruzi because of significantly higher screening and lower prevalence.rates for HIV. An index of infectious disease spread through blood transfusion was calculated for each country. The highest value was obtained for Bolivia (233 infections per 10,000 transfusions); in five other countries, it was 68 to 103 infections per 10,000. The risks were lower in Honduras (nine per 10,000), Ecuador (16 per 10,000), and Paraguay (19 per 10,000). While the real number of potentially infected units or infected persons is probably lower than our estimates because of false positives and already infected recipients, the data reinforce the need for an information system to assess the level of screening for infectious diseases in the blood supply. Since this information was collected, Chile, Colombia, Costa Rica, and Venezuela have made HCV screening mandatory; serologic testing for HCV has increased in those countries, as well as in El Salvador and Honduras. T. cruzi screening is now mandatory in Colombia, and the percentage of screened donors increased not only in Colombia, but also in Ecuador, El Salvador, and Paraguay. Laws to regulate blood transfusion practices have been enacted in Bolivia, Guatemala, and Peru. However, donor screening still needs to improve for one or more diseases in most countries.

  2. Evaluating uncertainties in regional climate simulations over South America at the seasonal scale

    Energy Technology Data Exchange (ETDEWEB)

    Solman, Silvina A. [Centro de Investigaciones del Mar y la Atmosfera CIMA/CONICET-UBA, DCAO/FCEN, UMI-IFAECI/CNRS, CIMA-Ciudad Universitaria, Buenos Aires (Argentina); Pessacg, Natalia L. [Centro Nacional Patagonico (CONICET), Puerto Madryn, Chubut (Argentina)

    2012-07-15

    This work focuses on the evaluation of different sources of uncertainty affecting regional climate simulations over South America at the seasonal scale, using the MM5 model. The simulations cover a 3-month period for the austral spring season. Several four-member ensembles were performed in order to quantify the uncertainty due to: the internal variability; the definition of the regional model domain; the choice of physical parameterizations and the selection of physical parameters within a particular cumulus scheme. The uncertainty was measured by means of the spread among individual members of each ensemble during the integration period. Results show that the internal variability, triggered by differences in the initial conditions, represents the lowest level of uncertainty for every variable analyzed. The geographic distribution of the spread among ensemble members depends on the variable: for precipitation and temperature the largest spread is found over tropical South America while for the mean sea level pressure the largest spread is located over the southeastern Atlantic Ocean, where large synoptic-scale activity occurs. Using nudging techniques to ingest the boundary conditions reduces dramatically the internal variability. The uncertainty due to the domain choice displays a similar spatial pattern compared with the internal variability, except for the mean sea level pressure field, though its magnitude is larger all over the model domain for every variable. The largest spread among ensemble members is found for the ensemble in which different combinations of physical parameterizations are selected. The perturbed physics ensemble produces a level of uncertainty slightly larger than the internal variability. This study suggests that no matter what the source of uncertainty is, the geographical distribution of the spread among members of the ensembles is invariant, particularly for precipitation and temperature. (orig.)

  3. The Role of Satellite Imagery to Improve Pastureland Estimates in South America

    Science.gov (United States)

    Graesser, J.

    2015-12-01

    Agriculture has changed substantially across the globe over the past half century. While much work has been done to improve spatial-temporal estimates of agricultural changes, we still know more about the extent of row-crop agriculture than livestock-grazed land. The gap between cropland and pastureland estimates exists largely because it is challenging to characterize natural versus grazed grasslands from a remote sensing perspective. However, the impasse of pastureland estimates is set to break, with an increasing number of spaceborne sensors and freely available satellite data. The Landsat satellite archive in particular provides researchers with immense amounts of data to improve pastureland information. Here we focus on South America, where pastureland expansion has been scrutinized for the past few decades. We explore the challenges of estimating pastureland using temporal Landsat imagery and focus on key agricultural countries, regions, and ecosystems. We focus on the suggested shift of pastureland from the Argentine Pampas to northern Argentina, and the mixing of small-scale and large-scale ranching in eastern Paraguay and how it could impact the Chaco forest to the west. Further, the Beni Savannahs of northern Bolivia and the Colombian Llanos—both grassland and savannah regions historically used for livestock grazing—have been hinted at as future areas for cropland expansion. There are certainly environmental concerns with pastureland expansion into forests; but what are the environmental implications when well-managed pasture systems are converted to intensive soybean or palm oil plantation? Tropical, grazed grasslands are important habitats for biodiversity, and pasturelands can mitigate soil erosion when well managed. Thus, we must improve estimates of grazed land before we can make informed policy and conservation decisions. This talk presents insights into pastureland estimates in South America and discusses the feasibility to improve current

  4. Climate variability and human impact on the environment in South America during the last 2000 years: synthesis and perspectives

    NARCIS (Netherlands)

    S.G.A. Flantua; H. Hooghiemstra; M. Vuillle; H. Behling; J.F. Carson; W.D. Gosling; I. Hoyos; M.P. Ledru; E. Montoya; F. Mayle; A. Maldonado; V. Rull; M.S. Tonello; B.S. Whiyney; C. González-Arango

    2015-01-01

    An improved understanding of present-day climate variability and change relies on high-quality data sets from the past two millennia. Global efforts to reconstruct regional climate modes are in the process of validating and integrating paleo-proxies. For South America, however, the full potential of

  5. Environmental controls on the distribution and diversity of lentic Chironomidae (Insecta: Diptera) across an altitudinal gradient in tropical South America

    NARCIS (Netherlands)

    F. Matthews-Bird; W.D. Gosling; A.L. Coe; M. Bush; F.E. Mayle; Y. Axford; S.J. Brooks

    2016-01-01

    To predict the response of aquatic ecosystems to future global climate change, data on the ecology and distribution of keystone groups in freshwater ecosystems are needed. In contrast to mid- and high-latitude zones, such data are scarce across tropical South America (Neotropics). We present the dis

  6. Climate variability and human impact in South America during the last 2000 years: synthesis and perspectives from pollen records

    NARCIS (Netherlands)

    S.G.A. Flantua; H. Hooghiemstra; M. Vuille; H. Behling; J.F. Carson; W.D. Gosling; I. Hoyos; M.P. Ledru; E. Montoya; F. Mayle; A. Maldonado; V. Rull; M.S. Tonello; B.S. Whitney; C. González-Arango

    2016-01-01

    An improved understanding of present-day climate variability and change relies on high-quality data sets from the past 2 millennia. Global efforts to model regional climate modes are in the process of being validated against, and integrated with, records of past vegetation change. For South America,

  7. Why are forests so scarce in subtropical South America? The shaping roles of climate, fire and livestock

    NARCIS (Netherlands)

    Bernardi de Leon, Rafael; Holmgren, Milena; Arim, Matías; Scheffer, Marten

    2016-01-01

    Forest cover is notoriously sparse across neotropical southeastern South America. In particular, the practically treeless landscapes of the Campos, as they are locally known, have puzzled ecologists since Darwin's time. We used remote-sensing information and spatial regression models to relate tr

  8. Ranking Business and Economics Journals in South America Using the Scientific Electronic Library Online (SciELO)

    Science.gov (United States)

    Alexander, Jennifer K.; Pradenas, Lorena; Parada, Victor; Scherer, Robert F.

    2012-01-01

    Access to published research for knowledge creation and education in the administrative science disciplines in South America has been enhanced since the introduction of the Scientific Electronic Library Online (SciELO). Although SciELO has been available as an online journal indexing and publication service since 1998, there have been no…

  9. Neothalassius, a new genus of Parathalassiinae (Diptera: Dolichopodidae s.lat.) from the Pacific coast of South America.

    Science.gov (United States)

    Brooks, Scott E; Cumming, Jeffrey M

    2016-01-15

    A new genus, Neothalassius gen. nov., and two new species, Neothalassius triton sp. nov. and Neothalassius villosus sp. nov., are described from rocky shorelines along the Pacific seacoast of South America. The phylogenetic placement of Neothalassius within the subfamily Parathalassiinae is discussed.

  10. Gastroptychus Cavimurus sp. nov., a new Chirostylid (Crustacea, Decapoda, Anomura) from off the western coast of South America

    NARCIS (Netherlands)

    Baba, K.

    1977-01-01

    During the second cruise of the Japanese Research Vessel "Kaiyo Maru" to the western coast of South America in 1968-69, Dr. Osame Tabeta of the Shimonoseki University of Fisheries, then on the staff of the Kyushu University, collected a number of galatheids off the northern Peruvian coast. All of th

  11. A comparative study of Taiwan's short-term medical missions to the South Pacific and Central America

    Directory of Open Access Journals (Sweden)

    Chiu Ya-Wen

    2012-12-01

    Full Text Available Abstract Background Taiwan has been dispatching an increasing number of short-term medical missions (STMMs to its allied nations to provide humanitarian health care; however, overall evaluations to help policy makers strengthen the impact of such missions are lacking. Our primary objective is to identify useful strategies by comparing STMMs to the South Pacific and Central America. Methods The data for the evaluation come from two main sources: the official reports of 46 missions to 11 countries in Central America and 25 missions to 8 countries in the South Pacific, and questionnaires completed by health professionals who had participated in the above missions. In Central America, STMMs were staffed by volunteer health professionals from multiple institutions. In the South Pacific, STMMs were staffed by volunteer health professionals from single institutions. Results In comparison to STMMs to Central America, STMMs to the South Pacific accomplished more educational training for local health providers, including providing heath-care knowledge and skills (p Conclusions Health-care services provided by personnel from multiple institutions are as efficient as those from single institutions. Proficiency in the native language and provision of education for local health-care workers are essential for conducting a successful STMM. Our data provide implications for integrating evidence into the deployment of STMMs.

  12. Ranking Business and Economics Journals in South America Using the Scientific Electronic Library Online (SciELO)

    Science.gov (United States)

    Alexander, Jennifer K.; Pradenas, Lorena; Parada, Victor; Scherer, Robert F.

    2012-01-01

    Access to published research for knowledge creation and education in the administrative science disciplines in South America has been enhanced since the introduction of the Scientific Electronic Library Online (SciELO). Although SciELO has been available as an online journal indexing and publication service since 1998, there have been no…

  13. CULTURE STUDIES ON THE LIFE-HISTORY OF CHORDARIA-LINEARIS (PHAEOPHYCEAE) FROM TIERRA-DEL-FUEGO, SOUTH-AMERICA

    NARCIS (Netherlands)

    PETERS, AF

    1992-01-01

    Studies of laboratory cultures of Chordaria linearis (Hooker et Harvey) Cotton from southernmost South America revealed that this species has an obligate sexual life history in which a macroscopic sporophyte alternates with a monoecious microscopic gametophyte. Sexual reproduction is isogamous and u

  14. Measurements of sulfur dioxide, ozone and ammonia concentrations in Asia, Africa, and South America using passive samplers

    CSIR Research Space (South Africa)

    Carmichael, GR

    2003-03-01

    Full Text Available , Africa, South America, and Europe. The median SO2 concentrations vary from a high of 13 ppb at Linan, China, to < 0.03 ppb at four stations. At 30 of 50 regional stations, the observed median concentrations are < 1 ppb. Median ammonia concentrations range...

  15. Rock Art at the Pleistocene/Holocene Boundary in Eastern South America

    Science.gov (United States)

    Neves, Walter A.; Araujo, Astolfo G. M.; Bernardo, Danilo V.; Kipnis, Renato; Feathers, James K.

    2012-01-01

    Background Most investigations regarding the First Americans have primarily focused on four themes: when the New World was settled by humans; where they came from; how many migrations or colonization pulses from elsewhere were involved in the process; and what kinds of subsistence patterns and material culture they developed during the first millennia of colonization. Little is known, however, about the symbolic world of the first humans who settled the New World, because artistic manifestations either as rock-art, ornaments, and portable art objects dated to the Pleistocene/Holocene transition are exceedingly rare in the Americas. Methodology/Principal Findings Here we report a pecked anthropomorphic figure engraved in the bedrock of Lapa do Santo, an archaeological site located in Central Brazil. The horizontal projection of the radiocarbon ages obtained at the north profile suggests a minimum age of 9,370±40 BP, (cal BP 10,700 to 10,500) for the petroglyph that is further supported by optically stimulated luminescence (OSL) dates from sediment in the same stratigraphic unit, located between two ages from 11.7±0.8 ka BP to 9.9±0.7 ka BP. Conclusions These data allow us to suggest that the anthropomorphic figure is the oldest reliably dated figurative petroglyph ever found in the New World, indicating that cultural variability during the Pleistocene/Holocene boundary in South America was not restricted to stone tools and subsistence, but also encompassed the symbolic dimension. PMID:22384187

  16. Are recommended standards for diabetes care met in Central and South America? A systematic review.

    Science.gov (United States)

    Mudaliar, Uma; Kim, Woon-Cho; Kirk, Katy; Rouse, Chaturia; Narayan, K M Venkat; Ali, Mohammed

    2013-06-01

    We evaluated quality of diabetes care in low- and middle-income countries (LMIC) of Central and South America by documenting the ability to meet the guideline-recommended targets. We also identified barriers to achieving goals of treatment and characteristics of successful programs. We searched the National Library of Medicine and Embase databases to systematically compile literature that reported on guideline-recommended processes of care (annual foot, eye, urine examinations, and regular blood glucose testing) and risk factor control (glycemic, blood pressure, and lipid levels) among people with diabetes since 1980. We compared risk factor control across clinic and household populations and benchmarked against the IDF guidelines. The available literature was largely from Mexico, Jamaica, and Brazil with little data from rural regions or smaller countries. Twenty-nine clinic-based and ten population-based studies showed a consistent failure to meet recommended care goals due to multiple underlying social and economic themes. Across all studies, the proportion of those not meeting targets ranged from 13.0 to 92.2% for glycemic control, 4.6 to 92.0% for blood pressure, and 28.2 to 78.3% for lipids. Few studies report quality of diabetes care in LMICs of the Americas, and heterogeneity across studies limits our understanding. Greater regard for audits, use of standardized reporting methods, and an emphasis on overcoming barriers to care are required. Published by Elsevier Ireland Ltd.

  17. Deep Earthquake Mechanics Inferred From Fault-Plane Orientations in Central South America

    Science.gov (United States)

    Warren, L. M.; Biryol, C. B.; Beck, S. L.

    2007-12-01

    To place constraints on the physical mechanisms of deep earthquakes, we analyze the rupture properties of >30 intraslab earthquakes with MW >5.7 in central South America (15°--25°S). For all earthquakes, we perform a directivity analysis to estimate the rupture vector and identify the fault plane. After comparing the results with synthetics, we can distinguish the fault plane of the focal mechanism for ~1/3 of these earthquakes. For the largest earthquakes, we also invert for the slip distribution on the fault plane. At intermediate depths, we test whether earthquakes result from dehydration embrittlement reactivating the steep, trenchward-dipping faults of the outer rise. After accounting for the angle of subduction, these faults would be approximately vertical. This prediction contrasts with the orientation of faults identified between 100--300 km depth, which are all subhorizontal and instead suggest the creation of a new system of faults. The exclusive occurrence of subhorizontal faults agrees with previous studies in the Tonga-Kermadec and Middle America subduction zones. The similarity in results between the three subduction zones despite large differences in temperature, subduction velocity, and subduction angle suggests that the earthquake-generating mechanism is controlled by pressure rather than tectonic parameters. Deeper than 300 km, earthquakes occur along both subhorizontal and subvertical fault planes.

  18. Freshwater discharge into the Caribbean Sea from the rivers of Northwestern South America (Colombia): Magnitude, variability and recent changes

    Science.gov (United States)

    Restrepo, Juan Camilo; Ortíz, Juan Carlos; Pierini, Jorge; Schrottke, Kerstin; Maza, Mauro; Otero, Luís; Aguirre, Julián

    2014-02-01

    The monthly averaged freshwater discharge data from ten rivers in northern Colombia (Caribbean alluvial plain) draining into the Caribbean Sea were analysed to quantify the magnitudes, to estimate long-term trends, and to evaluate the variability of discharge patterns. These rivers deliver ∼340.9 km3 yr-1 of freshwater to the Caribbean Sea. The largest freshwater supply is provided by the Magdalena River, with a mean discharge of 205.1 km3 yr-1 at Calamar, which is 26% of the total fluvial discharge into this basin. From 2000 to 2010, the annual streamflow of these rivers increased as high as 65%, and upward trends in statistical significance were found for the Mulatos, Canal del Dique, Magdalena, and Fundación Rivers. The concurrence of major oscillation processes and the maximum power of the 3-7 year band fluctuation defined a period of intense hydrological activity from approximately 1998-2002. The wavelet spectrum highlighted a change in the variability patterns of fluvial systems between 2000 and 2010 characterised by a shift towards a quasi-decadal process (8-12 years) domain. The Intertropical Convergence Zone (ITCZ), El Niño - Southern Oscillation (ENSO) events, and quasi-decadal climate processes are the main factors controlling the fluvial discharge variability of these fluvial systems.

  19. GEOGRAPHIC BODY SIZE AND SHAPE VARIATION IN A MAINLAND Anolis (SQUAMATA: DACTYLOIDAE FROM NORTHWESTERN SOUTH AMERICA (COLOMBIA

    Directory of Open Access Journals (Sweden)

    MARTHA L. CALDERÓN-ESPINOSA

    2014-01-01

    Full Text Available Anolis auratus se distribuye desde Costa Rica en Centro América, el norte de Sur América, incluyendo Colombia, Venezuela, norte de Brasil, Surinam y las Guyanas. En Colombia, su amplia distribución en distintas zonas de vida sugiere que estos lagartos ocupan distintos ambientes, y por tanto, posiblemente exhiben variación geográfica en el uso de microhabitat. Por otra parte, algunas observaciones sugieren que estos lagartos prefieren zonas abiertas, seleccionando pastizales y por tanto, una hipótesis alternativa es que usan el mismo microhabitat en toda su distribución. En Anolis, las variables corporales relacionadas con el movimiento (tamaño y forma corporal definen el uso del microhabitat, así que pueden esperarse dos patrones en esta especie: tamaño y forma corporal conservativos o altamente variables a lo largo de su distribución. Caracterizamos la variación geográfica en variables morfométricas de esta especie en Colombia. Hembras y machos mostraron tamaño corporal similar, pero fueron distintos en la forma del cuerpo. La forma corporal varía también en machos y hembras de distintas regiones, sugiriendo un uso heterogéneo del microhabitat estructural. Como alternativa, la divergencia filoge- nética entre poblaciones podría explicar las diferencias obser- vadas. La ausencia de datos ecológicos y filogenéticos para la especie limita las hipótesis sobre causas de este patrón. Provee- mos un marco general para explorar hipótesis que expliquen la evolución de tamaño y forma corporal en esta especie.

  20. Molecular paleoparasitological diagnosis of Ascaris sp. from coprolites: new scenery of ascariasis in pre-Colombian South America times

    Directory of Open Access Journals (Sweden)

    Daniela Leles

    2008-02-01

    Full Text Available Paleoparasitological studies using microscopy showed that Ascarisand Trichuris trichiura are the human intestinal parasites most found in archaeological sites. However, in pre-Columbian South American archaeological sites, Ascaris is rare. In this work we standardized a molecular methodology for Ascaris diagnosis directly from ancient DNA retrieved from coprolites. Using cythochrome b gene (142 bp target, ancient DNA sequences were retrieved from South American samples, negative by microscopy. Moreover, the methodology applied was sensitive enough to detect ancient DNA extracted from 30 Ascaris eggs from an European coprolite. These results revealed a new scenery for the paleodistribution of Ascaris in South America.

  1. Benefits of Sharing Information: Supermodel Ensemble and Applications in South America

    Science.gov (United States)

    Dias, P. L.

    2006-05-01

    A model intercomparison program involving a large number of academic and operational institutions has been implemented in South America since 2003, motivated by the SALLJEX Intercomparison Program in 2003 (a research program focused on the identification of the role of the Andes low level jet moisture transport from the Amazon to the Plata basin) and the WMO/THORPEX (www.wmo.int/thorpex) goals to improve predictability through the proper combination of numerical weather forecasts. This program also explores the potential predictability associated with the combination of a large number of possible scenarios in the time scale of a few days to up to 15 days. Five academic institutions and five operational forecasting centers in several countries in South America, 1 academic institution in the USA, and the main global forecasting centers (NCEP, UKMO, ECMWF) agreed to provide numerical products based on operational and experimental models. The metric for model validation is concentrated on the fit of the forecast to surface observations. Meteorological data from airports, synoptic stations operated by national weather services, automatic data platforms maintained by different institutions, the PIRATA buoys etc are all collected through LDM/NCAR or direct transmission. Approximately 40 models outputs are available on a daily basis, twice a day. A simple procedure based on data assimilation principles was quite successful in combining the available forecasts in order to produce temperature, dew point, wind, pressure and precipitation forecasts at station points in S. America. The procedure is based on removing each model bias at the observational point and a weighted average based on the mean square error of the forecasts. The base period for estimating the bias and mean square error is of the order of 15 to 30 days. Products of the intercomparison model program and the optimal statistical combination of the available forecasts are public and available in real time (www

  2. About the link of intraplate earthquakes allocations for South and North America with gravity field anomalies

    Science.gov (United States)

    Ryzhii, B. P.; Nachapkin, N. I.; Milanovsky, S. Yu.

    2003-04-01

    According developed concept the areas heightened intraplate seismicity are connected with the increased silica contents in the rocks, i.e. with patterns of acidic composition and, accordingly, with negative Bouguer gravity anomalies. Done statistical analysis of intraplate allocation of earthquakes on territory of Russia, Africa and Australia has confirmed effect of correlation of their position with areas of negative Bouguer anomalies. In this paper we made pattern analysis of the link of areas heightened intraplate seismicity for South and North America with anomalies of a gravity field - Bouguer and isostatic. If Bouguer anomalies are mainly related to morphology and composition of structural complexes of Earth crust, the isostatic anomalies, as a rule, are connected with acting tectonic forces and characterize a modern stress of Earth crust. For South America we analyzed 139 seismic events, which have occurred in a crust of Brazilian Platform in the period from 1692 to 2002. In regions with negative values of Bouguer anomalies, smaller than its mean for the Platform (-30 mgal), there occur 70% of all earthquakes. The correlation of a magnitude and depth of a hypocenter of earthquake is supervised depending on the value of Bouguer anomalies in its epicenter. In regions with positive values of isostatic anomaly, larger its mean magnitude for the Platform (1 mgal), there occur 77 % of all earthquakes. For North America we analyzed 383 seismic events which have occurred in a crust of North-American Platform in a period with 1929 on 2002. From 383 events 288 (75 %) has taken place in areas with negative values of Bouguer anomalies and 95 (25 %) - with positive values. Thus, the amount of earthquakes recorded in a negative gravitational field, in 4 times exceeds an amount of earthquakes in a positive field. At values of isostatic anomalies close to normal (-10 - 10 mgal) there was 55 % of all earthquakes and 41 % - recorded in ecstatically disturbed regions at values

  3. Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America.

    Science.gov (United States)

    Mitchell, Kieren J; Bray, Sarah C; Bover, Pere; Soibelzon, Leopoldo; Schubert, Blaine W; Prevosti, Francisco; Prieto, Alfredo; Martin, Fabiana; Austin, Jeremy J; Cooper, Alan

    2016-04-01

    The Tremarctinae are a subfamily of bears endemic to the New World, including two of the largest terrestrial mammalian carnivores that have ever lived: the giant, short-faced bears Arctodus simus from North America and Arctotherium angustidens from South America (greater than or equal to 1000 kg). Arctotherium angustidens became extinct during the Early Pleistocene, whereas Arctodus simus went extinct at the very end of the Pleistocene. The only living tremarctine is the spectacled bear (Tremarctos ornatus), a largely herbivorous bear that is today only found in South America. The relationships among the spectacled bears (Tremarctos), South American short-faced bears (Arctotherium) and North American short-faced bears (Arctodus) remain uncertain. In this study, we sequenced a mitochondrial genome from an Arctotherium femur preserved in a Chilean cave. Our molecular phylogenetic analyses revealed that the South American short-faced bears were more closely related to the extant South American spectacled bear than to the North American short-faced bears. This result suggests striking convergent evolution of giant forms in the two groups of short-faced bears (Arctodus and Arctotherium), potentially as an adaptation to dominate competition for megafaunal carcasses. © 2016 The Author(s).

  4. Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America

    Science.gov (United States)

    Bover, Pere; Soibelzon, Leopoldo; Schubert, Blaine W.; Prevosti, Francisco; Prieto, Alfredo; Martin, Fabiana; Austin, Jeremy J.; Cooper, Alan

    2016-01-01

    The Tremarctinae are a subfamily of bears endemic to the New World, including two of the largest terrestrial mammalian carnivores that have ever lived: the giant, short-faced bears Arctodus simus from North America and Arctotherium angustidens from South America (greater than or equal to 1000 kg). Arctotherium angustidens became extinct during the Early Pleistocene, whereas Arctodus simus went extinct at the very end of the Pleistocene. The only living tremarctine is the spectacled bear (Tremarctos ornatus), a largely herbivorous bear that is today only found in South America. The relationships among the spectacled bears (Tremarctos), South American short-faced bears (Arctotherium) and North American short-faced bears (Arctodus) remain uncertain. In this study, we sequenced a mitochondrial genome from an Arctotherium femur preserved in a Chilean cave. Our molecular phylogenetic analyses revealed that the South American short-faced bears were more closely related to the extant South American spectacled bear than to the North American short-faced bears. This result suggests striking convergent evolution of giant forms in the two groups of short-faced bears (Arctodus and Arctotherium), potentially as an adaptation to dominate competition for megafaunal carcasses. PMID:27095265

  5. Nazca - South America Convergence and Motion of the North Andes Block

    Science.gov (United States)

    La Femina, P. C.; Mora-paez, H.; Mothes, P. A.; Ruiz, G.

    2012-12-01

    The North Andes block (NAB) is a hypothesized tectonic block that moves (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). We investigate the kinematics of NAB motion utilizing a velocity field based on new continuous GPS networks and existing episodic GPS data in Ecuador and Colombia. The new velocity field and published earthquake slip vectors are inverted to solve for the Euler vector of the NAB and interseismic elastic strain accumulation on block-bounding faults using a block modeling approach. At the latitude of Ecuador, the NAB is rigid with transpressional deformation accommodating northeastward motion along its boundary with South America. In central to northern Colombia, the NAB is dissected by several prominent shear zones. We test a suite of block models to investigate the tectonic nature of the NAB 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 and upper plate faults capable of generating M>6 earthquakes.

  6. Recent Changes in the Annual Mean Regional Hadley Circulation and Their Impacts on South America

    Directory of Open Access Journals (Sweden)

    Ana Carolina Vasques Freitas

    2015-01-01

    Full Text Available This work employs the regional climate model RegCM4 and observational datasets to investigate the impacts of changes in the intensity and poleward edge of regional HC over South America (HCSA on the patterns of wind, geopotential height, precipitation, and temperature during the period 1996–2011. Significant trends of HCSA intensification and poleward expansion are found during the period analyzed. To evaluate the effects of these changes over SA, two composites, representing the intensification and poleward expansion cases, are examined separately. Significant correlations are seen between the temperature, zonal wind, and the HCSA intensity over the northern, central, and southern regions of SA and South Atlantic. Results show that, in both composites, regions with anomalous easterly (westerly winds coming from (towards the Atlantic Ocean have negative (positive correlations with the HCSA intensity and poleward edge. The model performance varies regionally and the southern SA region exhibits better agreement with the observations. The role of the sea surface temperatures in driving the changes in the HCSA is examined. Notable similarity is found in the results for the two cases analyzed, which could indicate that, in most cases, the changes in the intensity and poleward edge of the HCSA are occurring simultaneously.

  7. Hans Kelsen – The Reception of “Pure Theory” in South America, Particularly in Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Abreu Boucault

    2015-12-01

    Full Text Available This article aims to examine the reception of « Pure theory of Law », of Hans Kelsen in some South-American countries, throughout institutional approaches and also the diffusion of this theory as well its acceptance by cultural agents who represented academic and professional law environment, in Uruguay, Colombia, Argentina and Brazil. The historical period of this study concerns the early times of 40 till our days. Although the reference of Kelsen’s thought about theory of law may appear as a constant feature on South-American jurists, mainly till the decade of 1980, actually we can identify real problems that claim for a falsehood about the guidelines of the pure theory of law and ambiguities in connection to theoretical issues within positivist traditions in face of authoritarian governments in Latin America.

  8. [Can informal employment be compared in South America? Analysis of its definition, measurement and classification].

    Science.gov (United States)

    Ruiz, Marisol E; Tarafa Orpinell, Gemma; Jódar Martínez, Pere; Benach, Joan

    2015-01-01

    To characterize and analyze the situation of informal employment with regard to its definition, measurement and classification in South American countries. A literature review was conducted from four databases and grey literature through a scoping review, which included reports from international organizations and from the 12 countries in South America. The data were analyzed by evaluating content and establishing similarities among countries. The data reviewed showed a disparity in the definitions used, although many countries define informal employment as workers with no contract. Most countries measured informal employment through household surveys, but due to the differences in classifications, the information found was heterogeneous, with little standardization among registries. Therefore, the data could not be compared at a regional level. The definition of the International Labour Organization was not useful to study informal employment in the countries studied. The definition should include protected and unprotected workers. An appropriate and specific definition of informal employment would allow nuances to be studied within the concept, revealing the loopholes faced by most of the population working informally. The key to meaningful comparisons within the study region is to incorporate common indicators among local registration systems (measurement) in order to determine the public health impact in the informally employed population. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

  9. Extreme rainfall, vulnerability and risk: a continental-scale assessment for South America

    Science.gov (United States)

    Vorosmarty, Charles J.; de Guenni, Lelys Bravo; Wollheim, Wilfred M.; Pellerin, Brian A.; Bjerklie, David M.; Cardoso, Manoel; D'Almeida, Cassiano; Colon, Lilybeth

    2013-01-01

    Extreme weather continues to preoccupy society as a formidable public safety concern bearing huge economic costs. While attention has focused on global climate change and how it could intensify key elements of the water cycle such as precipitation and river discharge, it is the conjunction of geophysical and socioeconomic forces that shapes human sensitivity and risks to weather extremes. We demonstrate here the use of high-resolution geophysical and population datasets together with documentary reports of rainfall-induced damage across South America over a multi-decadal, retrospective time domain (1960–2000). We define and map extreme precipitation hazard, exposure, affectedpopulations, vulnerability and risk, and use these variables to analyse the impact of floods as a water security issue. Geospatial experiments uncover major sources of risk from natural climate variability and population growth, with change in climate extremes bearing a minor role. While rural populations display greatest relative sensitivity to extreme rainfall, urban settings show the highest rates of increasing risk. In the coming decades, rapid urbanization will make South American cities the focal point of future climate threats but also an opportunity for reducing vulnerability, protecting lives and sustaining economic development through both traditional and ecosystem-based disaster risk management systems.

  10. Current practice in regional anaesthesia in South America: An online survey.

    Science.gov (United States)

    Corvetto, M A; Carmona, J; Vásquez, M I; Salgueiro, C; Crostón, J; Sosa, R; Folle, V; Altermatt, F R

    2017-01-01

    A survey was conducted in order to obtain a profile of the practice of regional anesthesia in South America, and determine the limitations of its use. After institutional ethics committee approval, a link to an online questionnaire was sent by e-mail to anaesthesiologists in Argentina, Bolivia, Chile, Colombia, Panamá, Paraguay, Perú, and Uruguay. The questionnaire was processed anonymously. A total of 1,260 completed questionnaires were received. The results showed that 97.6% of the anaesthesiologists that responded used regional anaesthesia in clinical practice, 66.9% performed peripheral nerve block (PNB) regularly, 21.6% used continuous PNB techniques, and 4.6% used stimulating catheters. The primary source of training was residency programs. As regards PNB, the most common performed were interscalene (52.3%), axillary (45.1%), femoral (43.2%), and ankle block (43%). As regards the localisation technique employed, 16% used paraesthesia, 44.2% used a peripheral nerve stimulator, and 18.1% ultrasound guidance. Regional anaesthesia and PNB are commonly used among South American anaesthesiologists. Considering that each country has its own profile for use, this profile should guide training in clinical practice, especially in residency programs. Copyright © 2016 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. An operational high resolution ensemble kalman filter data assimilation cycle over South America

    Science.gov (United States)

    Cossetin, Camila; Goncalves, Luis; Silveira, Bruna; Vendrasco, Eder; Khamis, Eduardo; Sapucci, Luiz

    2016-04-01

    The brazilian Center for Weather Forecast and Climate Studies (CPTEC/INPE) has recently initiated an effort to develop operationally a high resolution probabilistic mesoscale analysis over the continental South America and portions of the surrounding south Pacific and Atlantic oceans. This work presents a high resolution regional ensemble Kalman filter (EnKF) system with the WRF model. It uses the gridpoint statistical interpolation (GSI) mantained by the Developmental Testbed Center (DTC) for observational data processing and observation operators. The initial tests were run at approximately 9 Km of spatial resolution and 20 members with 6-hourly data assimilation cycles using all regional observations and selected satellite radiances (AMSU-A, MHS and HIRS). The impact of the choice of covariance localization and covariance inflation in the model performance is assessed to demonstrate the sensitive to the tunning. A two-weeks simulation is performed to illustrate the system adjustment (spin up) and how the model errors and innovation respond during the first days of run. Furthermore, the relative contribution of satellite brightness temperature assimilation to the analysis increments is also evaluated.

  12. High-resolution hydraulic parameter maps for surface soils in tropical South America

    Science.gov (United States)

    Marthews, T. R.; Quesada, C. A.; Galbraith, D. R.; Malhi, Y.; Mullins, C. E.; Hodnett, M. G.; Dharssi, I.

    2014-05-01

    Modern land surface model simulations capture soil profile water movement through the use of soil hydraulics sub-models, but good hydraulic parameterisations are often lacking, especially in the tropics. We present much-improved gridded data sets of hydraulic parameters for surface soil for the critical area of tropical South America, describing soil profile water movement across the region to 30 cm depth. Optimal hydraulic parameter values are given for the Brooks and Corey, Campbell, van Genuchten-Mualem and van Genuchten-Burdine soil hydraulic models, which are widely used hydraulic sub-models in land surface models. This has been possible through interpolating soil measurements from several sources through the SOTERLAC soil and terrain data base and using the most recent pedotransfer functions (PTFs) derived for South American soils. All soil parameter data layers are provided at 15 arcsec resolution and available for download, this being 20x higher resolution than the best comparable parameter maps available to date. Specific examples are given of the use of PTFs and the importance highlighted of using PTFs that have been locally parameterised and that are not just based on soil texture. We discuss current developments in soil hydraulic modelling and how high-resolution parameter maps such as these can improve the simulation of vegetation development and productivity in land surface models.

  13. A Taxonomic Update of Small Mammal Plague Reservoirs in South America.

    Science.gov (United States)

    Bonvicino, Cibele R; Oliveira, João A; Cordeiro-Estrela, Pedro; D'andrea, Paulo S; Almeida, Alzira M P

    2015-10-01

    Plague is a disease of epidemic potential that may emerge with discontinuous outbreaks. In South America, 50 wild rodent species have been identified as plague reservoirs, in addition to one lagomorph and two marsupials. To review the nomenclature of plague reservoirs, we examined specimens collected in plague foci, carried out new surveys in Brazilian plague regions, and re-evaluated the nomenclature of South American reservoirs on the basis of the current literature. Five of the 15 species involved with plague in Argentina, three of 10 species involved with plague in Bolivia, three of the seven species involved with plague in Peru, five of the nine species involved with plague in Ecuador, and six of the nine species involved with plague in Brazil have undergone taxonomic changes. In the last 20 years, plague cases were recorded in Bolivia, Brazil, Ecuador, and Peru. These four countries have a high rodent species richness in plague foci, a fact that may be decisive for the maintenance of plague in the wild.

  14. Space-geodetic estimation of the nazca-south america euler vector

    Science.gov (United States)

    Angermann, D.; Klotz, J.; Reigber, C.

    1999-09-01

    GPS data from four sites in the Nazca Plate (Easter Island, Galapagos, Robinson Crusoe and San Felix Islands) and from five sites in the stable core of the South American Plate enabled us to estimate the Euler vector of the Nazca Plate with respect to South America. The observed velocities of Easter Island (6.6 cm/yr at 102.3°), Galapagos (5.1 cm/yr at 90.0°), Robinson Crusoe (6.6 cm/yr at 80.1°) and San Felix (6.0 cm/yr at 82.1°) are significantly slower than the global plate model NUVEL-1A velocites for those four sites. Our estimated Euler pole is located at 48.8°N, 91.7°W with a rate of 0.59°/m.y. The NUVEL-1A and earlier space-geodetic studies give rotation rates that are 20% faster.

  15. USING SRTM TO QUANTIFY SIZE PARAMETERS AND SPATIAL DISTRIBUTION OF ENDORHEIC BASINS IN SOUTHERN SOUTH AMERICA

    Directory of Open Access Journals (Sweden)

    Ralf Hesse

    2008-08-01

    Full Text Available The SRTM data set is the highest resolution DEM with global or continental coverage. It is therefore theDEM of choice for continental-scale geomorphological mapping and quantitative analysis. In this study,SRTM data are used for the identification and characterisation of endorheic basins in southern SouthAmerica (south of 19°S. The results show the feasibility of continental-scale quantitative geomorphologybased on SRTM data and provide insights into the distribution of closed basins. The largest endorheicbasin is located in the Puna region and consists of several interconnected sub-basins. This basin accountsfor 38.6 % (7877 km3 of the total volume of the endorheic basins identified in this study. Analyses of thegeographic distribution show a narrow longitudinal distribution between 64.5 and 71.5° W and a multimodallatitudinal distribution which is characterised by two groups of basins at 22.5–27.5°S and 37.5–50.0° Sand an almost complete absence of basins between 27.5 and 37.5° S. Problems and sources ofmisinterpretation arising from data quality and resolution are discussed. Further research, targeting in particularthe genesis and potential for paleoenvironmental reconstruction of closed basins in southern Argentina, iscalled for.

  16. Historical Biogeography of Five Characidium Fish Species: Dispersal from the Amazon Paleobasin to Southeastern South America

    Science.gov (United States)

    Sosa, Chrystian C.; Chacón-Vargas, Katherine; García-Merchán, Víctor Hugo

    2016-01-01

    Characidium is a Neotropical fish genus. Its distribution ranges from eastern Panama to northern Argentina, and it is an important component of the Neotropical ichthyofauna present in the major rivers of South America. We here provide an approximation to the dispersal and historical distributions of Characidium. The biogeographic history of five species of the genus was analyzed through nuclear RAG-2 and mitochondrial 16S genes and a time-calibrated phylogenetic analysis using three outgroup species. A biogeographical reconstruction was performed to estimate ancestral geographic ranges and infer the historical events that impacted the geographic distributions of Characidium species. Our results showed Characidium as a monophyletic group. The molecular clock suggests that the most recent common ancestor of Characidium originated during the Eocene, about 50.2 Mya. In addition, different dispersion and vicariance events could be inferred, which possibly gave rise to the present geographical distribution of the genus. Our results point to the rise of the Andean mountains and sea fluctuations as being important events in the formations and delimitation of different rivers, which influenced the distribution of South American ichthyofauna. PMID:27741308

  17. Modelling of the Effect of Biomass Burning Aerosol in South America

    Science.gov (United States)

    Thornhill, Gillian; Ryder, Claire; Highwood, Eleanor; Shaffrey, Len

    2017-04-01

    Modelling of biomass burning aerosol over S. America was undertaken using the HADGEM3 model in order to investigate the impact of absorbing aerosols on climate, particularly in the S. American region, as part of the SAMBBA project. The model was run for a 30 year period with a resolution of N96 (1.25 x 1.875 degrees) and 85 vertical levels, using a bulk aerosol scheme (CLASSIC). In order to examine the impacts of biomass burning aerosol on radiative fluxes and climate, we performed two 30-year climate model runs with high and low emissions over South America (based on the years 2010 and 2000 respectively). Emissions outside of S. America are taken as the 1997-2000 mean for both runs. The emissions are taken from GFED 3.1, and scaled by a factor of 2 in the model. Other aerosol emissions, sea-surface temperatures and sea-ice are based on monthly climatological means. The results for September (the month of greatest emissions) show a reduction in the clear-sky surface SW radiation of 11.5 Wm-2 for the high emissions case over the area of the highest AOD compared to the low emissions case, with a corresponding reduction in the surface temperature of the order of 1 K and surface sensible heat flux of 4.3 Wm-2; the differences in the latent heat flux are less clearly correlated with the differences in the AOD spatially, with a smaller reduction of 1.8 Wm-2in the biomass burning area. The total cloud fraction also shows a reduction for the high emissions case, as expected from cloud 'burn-off' due to the semi-direct effect, with the greatest effect on the cloud layer in and just above the aerosol. We also see changes to the low-level (850mb) circulation, with a strengthening of the low-level jet to the east of the Andes, together with changes in the positioning of the S. Atlantic high pressure system. The results show the predicted effects on the radiation budgets and the semi-direct effect on the cloud cover; we are continuing to study the detailed effects on cloud

  18. The crust and lithosphere thicknesses in South America: trying to find the lithosphere- asthenosphere boundary

    Science.gov (United States)

    Heit, B.; Sodoudi, F.; Yuan, X.; Bianchi, M.; Kind, R.

    2007-05-01

    During the past years, a series of seismological investigations have been carried out to study the crustal and mantle structures all over the world. In South America, this investigation has not been an easy task as there are different regions where the geodynamics involves the subduction of an oceanic plate, the building of a mountain range as the Andes, the interaction with older lithosphere as the Brazilian Shield and the presence of active deformation fronts between the last two regions. In order to investigate the thickness of the lithosphere in such a complex context we have performed S-wave receiver function analysis (Vinnik and Farra, 2000; Li et al., 2004). The S receiver function technique looks for the S-to-P converted waves at seismic discontinuities beneath a station in the same way as the conventional P receiver function method that deals with P-to-S conversions. The S receiver function technique have proved to be useful to map the Moho and the LAB in many regions where other methods (i.e. surface waves) failed to provide reliable information (e.g. Li et al., 2004; Kumar et al., 2004a, 2004b; Sodoudi et al., 2006). We present here the results of S receiver function technique that has been applied to all the available temporary seismic experiments (e.g. BANJO, SEDA, REFUCA, BLSP) and the permanent stations from the IRIS network. We have been able to investigate the upper mantle discontinuities at all the depths beneath the stations and obtained coherent Moho depths along the entire Andes and in other South American continental regions. The LAB has been clearly detected below some stations, particularly those that are located far away from the subduction zone. By comparing our results with those from the P receiver functions, we have been able to further constrain the thicknesses of the crust and LAB in different regions including shields, mobile belts, basins and mountain ranges. At many stations we have also been able to map the upper mantle

  19. Carbonate sediment production in the equatorial continental shelf of South America: Quantifying Halimeda incrassata (Chlorophyta) contributions

    Science.gov (United States)

    Carneiro, Pedro Bastos de Macêdo; Morais, Jader Onofre de

    2016-12-01

    The middle and outer continental shelves of eastern equatorial South America (ESA) are characterized by intense production of carbonate sediments. Qualitative analyses of sediment deposits suggest that the calcareous green alga Halimeda incrassata is among the top CaCO3 producers. Nevertheless, no study so far has quantified its real contributions. To better understand the sediment dynamic in this area, we measured biomass, growth rates and calcium carbonate production by this alga. The species exhibited high growth rates (3.38 segments.individual-1.day-1), coverage (174 individuals.m-2) and biomass (214.02 g.m-2). Substitution of segments may allow a sedimentation rate of 1.53 mm.yr-1 and a complete turnover of the population every 60.2 days. The rapid growth indicates that this alga can produce as much CaCO3 (1.19 kg CaCO3.m-2.year-1) as other tropical organisms, such as corals and rhodoliths. In a conservative estimate, 773.500 tonnes of CaCO3 are produced per year in a 5000 km2 area off the northern coast of Brazil. Sedimentation rate seems to be higher than that promoted by continental inputs in middle and outer continental shelf. On the other hand, population turnover is twice as slow as in other H. incrassata assemblages, suggesting that South American populations are sensible to physical disturbances. New studies are necessary to accurately estimate H. incrassata coverage along the Brazilian coast and to integrate data on other CaCO3 producers, such as foraminifera and coralline algae. This would allow a better understanding of the role of South American continental shelf on the global carbon budget. Furthermore, analysis on the health of these organisms is urgent, since a decline in their populations could negatively affect ecosystems functioning and services.

  20. Warm and Dry Spells (WDS in Austral Winter over Central South America

    Directory of Open Access Journals (Sweden)

    P. Satyamurty

    2007-06-01

    Full Text Available The horizontal and vertical structure of unusually warm and dry spells (WDS over the central parts of South America during the winter and post-winter months (JJAS are studied. During WDS the mean temperature and humidity anomalies over central Brazil are about +4.1°C and −13.2%, respectively. The mean duration of WDS is 11 days and their mean frequency is less than one per year during the months of JJAS. Apparently, WDS have no preference for the phase of ENSO. Widespread and persistent subsidence in the middle troposphere is observed in tropical Brazil during WDS, which renders the lower tropospheric air warm and dry. The negative anomalies of the specific humidity are observed to be associated with the subsidence regions. A strong, slow moving ridge in the eastern South Pacific and a low-pressure center in northern Argentina are important surface characteristics during the WDS. A more detailed investigation of two specific WDS events, a strong event (August–September 1999 and a moderate one (June 2002, shows a blocking-like situation in the 500-hPa geopotential and surface pressure fields in the Pacific. The South Atlantic subtropical high somewhat approaches the continent. Strong northerlies over the central and eastern parts of Brazil are also observed in the lower troposphere. During WDS the regional circulation acquires summertime characteristics, except for the absence of precipitation, and the circulation in the meridional plane is in the opposite sense from the Hadley circulation. A frontal system, supported by a 500-hPa trough, advances into central Brazil, causing the dissipation of the anomalous situation.

  1. A review of Tertiary climate changes in southern South America and the Antarctic Peninsula. Part 1: Oceanic conditions

    Science.gov (United States)

    Le Roux, J. P.

    2012-03-01

    Oceanic conditions around southern South America and the Antarctic Peninsula have a major influence on climate patterns in these subcontinents. During the Tertiary, changes in ocean water temperatures and currents also strongly affected the continental climates and seem to have been controlled in turn by global tectonic events and sea-level changes. During periods of accelerated sea-floor spreading, an increase in the mid-ocean ridge volumes and the outpouring of basaltic lavas caused a rise in sea-level and mean ocean temperature, accompanied by the large-scale release of CO2. The precursor of the South Equatorial Current would have crossed the East Pacific Rise twice before reaching the coast of southern South America, thus heating up considerably during periods of ridge activity. The absence of the Antarctic Circumpolar Current before the opening of the Drake Passage suggests that the current flowing north along the present western seaboard of southern South American could have been temperate even during periods of ridge inactivity, which might explain the generally warm temperatures recorded in the Southeast Pacific from the early Oligocene to middle Miocene. Along the east coast of southern South America, water temperatures also fluctuated between temperate-cool and warm until the early Miocene, when the first incursion of temperate-cold to cold Antarctic waters is recorded. The cold Falkland/Malvinas Current initiated only after the middle Miocene. After the opening of the Drake Passage, the South Equatorial Current would have joined the newly developed, cold Antarctic Circumpolar Current on its way to Southern South America. During periods of increased sea-floor spreading, it would have contributed heat to the Antarctic Circumpolar Current that caused a poleward shift in climatic belts. However, periods of decreased sea-floor spreading would have been accompanied by diminishing ridge volumes and older, cooler and denser oceanic plates, causing global sea

  2. Complete molar pregnancy in adolescents from North and South America: Clinical presentation and risk of gestational trophoblastic neoplasia.

    Science.gov (United States)

    Soares, Renan Rocha; Maestá, Izildinha; Colón, José; Braga, Antonio; Salazar, Aleydah; Charry, Rafael Cortés; Sun, Sue Yazaki; Goldstein, Donald P; Berkowitz, Ross S

    2016-09-01

    To compare complete hydatidiform mole (CHM) clinical presentation and risk factors associated with GTN development between North American and South American adolescents. This non-concurrent cohort study was undertaken including adolescents with CHM referred to centers in North America (New England Trophoblastic Disease Center, Harvard University, USA), and South America (Botucatu Trophoblastic Disease Center-São Paulo State University, Brazil; Trophoblastic Unit of Central University of Venezuela and Maternidad Concepcion Palacios of Caracas, Venezuela) between 1990 and 2012. Data were obtained from medical records and pathology reports. Study participants were allocated into 2 groups: North America (NA) and South America (SA). In NA and SA, 13.1% and 30.9% of patients with hydatidiform mole were adolescents, respectively. Of these, 77.6% in NA and 86.1% in SA had pathologic diagnosis of CHM (p=0.121). Vaginal bleeding (SA=69% vs NA=51%; p=0.020), anemia (SA=48% vs NA=18%; p<0.001), and elevated serum hCG (SA=232,860mIU/mL vs NA=136,412mIU/mL; p=0.039) were more frequent in SA than in NA. Median gestational age at diagnosis (SA=12weeks, NA=11weeks; p=0.030) differed whereas GTN development rate (SA=20%, NA=27%; p=0.282) showed no significant difference between groups. Compared to NA, medical complications and clinical factors associated with post-molar GTN were more frequent among SA adolescents. Medical complications and clinical factors associated with GTN development were more frequent in SA than in NA adolescents with CHM, suggesting that, in South America, awareness about the importance of diagnosing molar pregnancy early and considering CHM in the differential diagnosis in adolescents suspected to be pregnant should be raised. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. On the Nature of Severe Orographic Thunderstorms near the Andes in Subtropical South America

    Science.gov (United States)

    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

  4. Accelerated greenhouse gases versus slow insolation forcing induced climate changes in southern South America since the Mid-Holocene

    Science.gov (United States)

    Berman, Ana Laura; Silvestri, Gabriel E.; Rojas, Maisa; Tonello, Marcela S.

    2017-01-01

    This paper is a pioneering analysis of past climates in southern South America combining multiproxy reconstructions and the state-of-the-art CMIP5/PMIP3 paleoclimatic models to investigate the time evolution of regional climatic conditions from the Mid-Holocene (MH) to the present. This analysis allows a comparison between the impact of the long term climate variations associated with insolation changes and the more recent effects of anthropogenic forcing on the region. The PMIP3 multimodel experiments suggest that changes in precipitation over almost all southern South America between MH and pre-industrial (PI) times due to insolation variations are significantly larger than those between PI and the present, which are due to changes in greenhouse gas concentrations. Anthropogenic forcing has been particularly intense over western Patagonia inducing reduction of precipitation in summer, autumn and winter as a consequence of progressively weaker westerly winds over the region, which have moved further poleward, between ca. 35-55°S and have become stronger south of about 50°S. Orbital variations between the MH to the PI period increased insolation over southern South America during summer and autumn inducing warmer conditions in the PI, accentuated by the effect of anthropogenic forcing during the last century. On the other hand, changes in orbital parameters from the MH to the PI period reduced insolation during winter and spring inducing colder conditions, which have been reversed by the anthropogenic forcing.

  5. Devonian-Carboniferous unconformity in Argentina and its relation to the Eo-Hercynian orogeny in southern South America

    Science.gov (United States)

    López-Gamundí, O. R.; Rossello, E. A.

    1993-04-01

    The Devonian-Carboniferous contact in southern South America, characterized by a sharp unconformity, has been related to the Late Devonian-Early Carboniferous Eo-Hercynian orogeny. The Calingasta-Uspallata basin of western Argentina and the Sauce-Grande basin (Ventana Foldbelt) of eastern Argentina have been selected to characterize this unconformity. The Eo-Hercynian movements were accompanied in western Argentina by igneous activity related to a Late Devonian—Early Carboniferous magmatic arc mainly exposed today along the Andean Cordillera. This magmatic activity is partly reflected also in eastern Argentina (Ventana Foldbelt), where isotopic dates suggest a thermal event also related to the intrusions present to the west in the North Patagonian Massif and Sierras Pampeanas. The scarcity of Lower Carboniferous deposits in the stratigraphic record of southern South America suggests that the Early Carboniferous was a time interval dominated by uplift and erosion followed by widespread subsidence during the Middle and Late Carboniferous. The origin of the Eo-Hercynian orogeny can be linked with the convergence between the Arequipa Massif, and its southern extension, and the South American continent. Its effects are best represented along the ‘Palaeo-Pacific’ margin, although distant effects are discernible in the cratonic areas of eastern South America.

  6. Avian Influenza Virus Isolated in Wild Waterfowl in Argentina: Evidence of a potentially unique phylogenetic lineage in South America

    Science.gov (United States)

    Pereda, Ariel J.; Uhart, Marcela; Perez, Alberto A.; Zaccagnini, Maria E.; La Sala, Luciano; Decarre, Julieta; Goijman, Andrea; Solari, Laura; Suarez, Romina; Craig, Maria I.; Vagnozzi, Ariel; Rimondi, Agustina; König, Guido; Terrera, Maria V.; Kaloghlian, Analia; Song, Haichen; Sorrell, Erin M.; Perez, Daniel R.

    2008-01-01

    Avian Influenza (AI) viruses have been sporadically isolated in South America. The most recent reports are from an outbreak in commercial poultry in Chile in 2002 and its putative ancestor from a wild bird in Bolivia in 2001. Extensive surveillance in wild birds was carried out in Argentina during 2006-2007. Using RRT-PCR, 12 AI positive detections were made from cloacal swabs. One of those positive samples yielded an AI virus isolated from a wild kelp gull (Larus dominicanus) captured in the South Atlantic coastline of Argentina. Further characterization by nucleotide sequencing reveals that it belongs to the H13N9 subtype. Phylogenetic analysis of the 8 viral genes suggests that the 6 internal genes are related to the isolates from Chile and Bolivia. The analysis also indicates that a cluster of phylogenetically related AI viruses from South America may have evolved independently, with minimal gene exchange, from influenza viruses in other latitudes. The data produced from our investigations are valuable contributions to the study of AI viruses in South America. PMID:18632129

  7. Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America

    Directory of Open Access Journals (Sweden)

    P. Castellanos

    2013-08-01

    Full Text Available Biomass burning is an important contributor to global total emissions of NOx (NO + NO2. Generally bottom-up fire emissions models calculate NOx emissions by multiplying fuel consumption estimates with static biome specific emission factors, defined in units of grams of NO per kilogram of dry matter consumed. Emission factors are a significant source of uncertainty in bottom-up fire emissions modeling because relatively few observations are available to characterize the large spatial and temporal variability of burning conditions. In this paper we use NO2 tropospheric column observations from the Ozone Monitoring Instrument (OMI from the year 2005 over South America to calculate monthly NOx emission factors for four fire types: deforestation, savanna/grassland, woodland, and agricultural waste burning. In general, the spatial trends in NOx emission factors calculated in this work are consistent with emission factors derived from in situ measurements from the region, but are more variable than published biome specific global average emission factors widely used in bottom up fire emissions inventories such as the Global Fire Emissions Database (GFED v3. Satellite based NOx emission factors also indicate substantial temporal variability in burning conditions. Overall, we found that deforestation fires have the lowest NOx emission factors, on average 30 % lower than the emission factors used in GFED v3. Agricultural fire NOx emission factors were the highest, on average a factor of 2 higher than GFED v3 values. For savanna, woodland, and deforestation fires early dry season NOx emission factors were a factor of ~1.5–2.0 higher than late dry season emission factors. A minimum in the NOx emission factor seasonal cycle for deforestation fires occurred in August, the time period of severe drought in South America in 2005. Our results support the hypothesis that prolonged dry spells may lead to an increase in the contribution of smoldering combustion

  8. Disaster resilience assessment and the global agenda: A journey from India to South America

    Science.gov (United States)

    Fanchiotti, Margherita; Torres, Jair; Burton, Christopher; Makarigakis, Alexandros

    2016-04-01

    Governments and stakeholders worldwide are placing great emphasis on fostering the resilience of communities to natural hazards and disasters. This is partially because communities that can increase their resilience are in a better position to withstand the adverse effects of damaging hazard events when they occur. With disaster risk reduction having emerged as a global challenge, the Sendai Framework for Disaster Risk Reduction 2015-2030 has recognised the need to invest in enhancing disaster resilience as a priority on the international agenda. In order to successfully build community resilience to natural hazards, it then becomes essential to first understand, identify and assess all sets of conditions that contribute to resilience. The ability to measure resilience is increasingly being identified as a key step towards disaster risk reduction as a result. Relatively few studies, however, have been conducted to develop guidelines for measuring the concept, and more research is needed to develop effective tools for assessment of resilience in developing countries. This is because various environmental, built-environment, and social factors will operate and interact differentially across disaster and development contexts. This paper presents preliminary findings from two large projects in which the authors have been involved, namely the 'Enhancing Natural HAzards resilience iN South America' (ENHANS) and 'Deltas, Vulnerability & Climate Change: Migration & Adaptation' (DECCMA) projects. In collaboration with the Global Earthquake Model (GEM), the Understanding and Managing Extremes (UME) School of the Institute for Advanced Study (IUSS) of Pavia and the University of Southampton, UNESCO is working on the development of methods for disaster resilience measurement in developing nations. The studies build on the available literature to provide an ad-hoc conceptual framework for the quantification of community resilience in each study site by means of a bottom

  9. Arboviral Etiologies of Acute Febrile Illnesses in Western South America, 2000–2007

    Science.gov (United States)

    Forshey, Brett M.; Guevara, Carolina; Laguna-Torres, V. Alberto; Cespedes, Manuel; Vargas, Jorge; Gianella, Alberto; Vallejo, Efrain; Madrid, César; Aguayo, Nicolas; Gotuzzo, Eduardo; Suarez, Victor; Morales, Ana Maria; Beingolea, Luis; Reyes, Nora; Perez, Juan; Negrete, Monica; Rocha, Claudio; Morrison, Amy C.; Russell, Kevin L.; J. Blair, Patrick; Olson, James G.; Kochel, Tadeusz J.

    2010-01-01

    Background Arthropod-borne viruses (arboviruses) are among the most common agents of human febrile illness worldwide and the most important emerging pathogens, causing multiple notable epidemics of human disease over recent decades. Despite the public health relevance, little is know about the geographic distribution, relative impact, and risk factors for arbovirus infection in many regions of the world. Our objectives were to describe the arboviruses associated with acute undifferentiated febrile illness in participating clinics in four countries in South America and to provide detailed epidemiological analysis of arbovirus infection in Iquitos, Peru, where more extensive monitoring was conducted. Methodology/Findings A clinic-based syndromic surveillance system was implemented in 13 locations in Ecuador, Peru, Bolivia, and Paraguay. Serum samples and demographic information were collected from febrile participants reporting to local health clinics or hospitals. Acute-phase sera were tested for viral infection by immunofluorescence assay or RT-PCR, while acute- and convalescent-phase sera were tested for pathogen-specific IgM by ELISA. Between May 2000 and December 2007, 20,880 participants were included in the study, with evidence for recent arbovirus infection detected for 6,793 (32.5%). Dengue viruses (Flavivirus) were the most common arbovirus infections, totaling 26.0% of febrile episodes, with DENV-3 as the most common serotype. Alphavirus (Venezuelan equine encephalitis virus [VEEV] and Mayaro virus [MAYV]) and Orthobunyavirus (Oropouche virus [OROV], Group C viruses, and Guaroa virus) infections were both observed in approximately 3% of febrile episodes. In Iquitos, risk factors for VEEV and MAYV infection included being male and reporting to a rural (vs urban) clinic. In contrast, OROV infection was similar between sexes and type of clinic. Conclusions/Significance Our data provide a better understanding of the geographic range of arboviruses in South

  10. Arboviral etiologies of acute febrile illnesses in Western South America, 2000-2007.

    Directory of Open Access Journals (Sweden)

    Brett M Forshey

    Full Text Available BACKGROUND: Arthropod-borne viruses (arboviruses are among the most common agents of human febrile illness worldwide and the most important emerging pathogens, causing multiple notable epidemics of human disease over recent decades. Despite the public health relevance, little is know about the geographic distribution, relative impact, and risk factors for arbovirus infection in many regions of the world. Our objectives were to describe the arboviruses associated with acute undifferentiated febrile illness in participating clinics in four countries in South America and to provide detailed epidemiological analysis of arbovirus infection in Iquitos, Peru, where more extensive monitoring was conducted. METHODOLOGY/FINDINGS: A clinic-based syndromic surveillance system was implemented in 13 locations in Ecuador, Peru, Bolivia, and Paraguay. Serum samples and demographic information were collected from febrile participants reporting to local health clinics or hospitals. Acute-phase sera were tested for viral infection by immunofluorescence assay or RT-PCR, while acute- and convalescent-phase sera were tested for pathogen-specific IgM by ELISA. Between May 2000 and December 2007, 20,880 participants were included in the study, with evidence for recent arbovirus infection detected for 6,793 (32.5%. Dengue viruses (Flavivirus were the most common arbovirus infections, totaling 26.0% of febrile episodes, with DENV-3 as the most common serotype. Alphavirus (Venezuelan equine encephalitis virus [VEEV] and Mayaro virus [MAYV] and Orthobunyavirus (Oropouche virus [OROV], Group C viruses, and Guaroa virus infections were both observed in approximately 3% of febrile episodes. In Iquitos, risk factors for VEEV and MAYV infection included being male and reporting to a rural (vs urban clinic. In contrast, OROV infection was similar between sexes and type of clinic. CONCLUSIONS/SIGNIFICANCE: Our data provide a better understanding of the geographic range of

  11. Status and challenges for conservation of small mammal assemblages in South America.

    Science.gov (United States)

    Kelt, Douglas A; Meserve, Peter L

    2014-08-01

    South America spans about 44° latitude, covers almost 18 million km(2) , and is second only to Africa in continental mammal species richness. In spite of this richness, research on the status of this fauna and on the nature and magnitude of contemporary threats remains limited. Distilling threats to this diverse fauna at a continental scale is challenging, in part because of the limited availability of rigorous studies. Recognizing this constraint, we summarize key threats to small mammals in South America, emphasizing the roles of habitat loss and degradation, direct persecution, and the increasing threat of climate change. We focus on three regional 'case studies': the tropical Andes, Amazonia and adjacent lowland regions, and the southern temperate region. We close with a brief summary of recent findings at our long-term research site in north-central Chile as they pertain to projected threats to this fauna. Habitat alteration is a pervasive threat that has been magnified by market forces and globalization (e.g. extensive agricultural development in Amazonia), and threatens increasing numbers of populations and species. Climate change poses even greater threats, from changes in rainfall and runoff regimes and resulting changes in vegetative structure and composition to secondary influences on fire dynamics. It is likely that many changes have yet to be recognized, but existing threats suggest that the future may bring dramatic changes in the distribution of many mammal taxa, although it is not clear if key habitat elements (vegetation) will respond as rapidly as climatic factors, leading to substantial uncertainty. Climate change is likely to result in 'winners' and 'losers' but available information precludes detailed assessment of which species are likely to fall into which category. In the absence of long-term monitoring and applied research to characterize these threats more accurately, and to develop strategies to reduce their impacts, managers already are

  12. The extinction of Equidae and Proboscidea in South America. A test using Carbon isotope data

    Directory of Open Access Journals (Sweden)

    Prado, J. L.

    2011-12-01

    Full Text Available Carbon isotopes, preserved in 166 samples of fossil teeth and bone, provide key data for understanding the ecology of extinct horses and gomphotheres during the Plio-Pleistocene in South America. To analyze the patterns of dietary partitioning throughout this time we divided the samples into 19 groups, taking into account the genus and the age of the corresponding localities. In this study, the diets of both groups are assessed to test extinction hypotheses. The strong resource partitioning among herbivores assumed under Co-evolutionary disequilibrium hypothesis is supported by isotopic data of horses from latest Pleistocene. Hippidon and Equus had very different diets. In contrast, species of gomphotheres from late Pleistocene in South America seem to have had less specialized diets containing a broad mix of both C3 and C4 plants, which is in line with the dietary assumptions of the mosaic-nutrient hypothesis, but does not support the assumptions of Co-evolutionary disequilibrium hypothesis.

    Los isótopos del carbono preservados en 166 muestras de dientes y huesos fósiles son un dato clave para entender la ecología de los de caballos y gonfoterios durante el Plio-Pleistoceno en América del Sur. Para analizar los cambios en las reconstrucciones de la dieta durante este lapso temporal hemos dividido las muestras en 19 grupos, teniendo en cuenta la sistemática y la cronología de cada localidad. En este estudio, las dietas de ambos grupos son evaluadas para probar las hipótesis sobre su extinción. El alto fraccionamiento en el uso de los recursos entre los herbívoros que asume la hipótesis del desequilibrio co-evolutivo es sustentada por los datos isotópicos de los caballos del Pleistoceno tardío. Hippidion y Equus tenían una dieta muy diferente. En contraste, las especies de gonfoterios de finales del Pleistoceno parecen tener una dieta menos especializada con una combinación de

  13. The Pali Aike Volcanic Field, Patagonia: slab-window magmatism near the tip of South America

    Science.gov (United States)

    D'Orazio, Massimo; Agostini, Samuele; Mazzarini, Francesco; Innocenti, Fabrizio; Manetti, Piero; Haller, Miguel J.; Lahsen, Alfredo

    2000-06-01

    The Pali Aike Volcanic Field (PAVF) represents the southernmost occurrence of the Cenozoic back-arc Patagonian Plateau Lavas. Its activity (Pliocene-Recent) started forming tabular lavas followed by the growth of about 470 essentially monogenetic volcanic centers (tuff-rings, maars, spatter and scoria cones). Azimuths of cone alignment, cone elongation and morphologic lineations show prevailing ENE-WSW and NW-SE trends. Erupted products consist mainly of alkaline basalt and basanite, with minor olivine basalt. PAVF rocks are quite primitive in composition (average Mg#=66, Ni=220 ppm and Cr=313 ppm) with relatively high TiO 2 (average 3.0 wt.%). Ultramafic garnet- and/or spinel-bearing xenoliths are found within PAVF volcanics. Chondrite-normalized REE patterns are significantly LREE-enriched and almost rectilinear [(La/Yb) N=10.9-21.0]. Primordial mantle-normalized distributions of incompatible trace elements, as well as Sr and Nd isotope ratios ( 87Sr/ 86Sr=0.70317-0.70339, 143Nd/ 144Nd=0.51290-0.51294), show values typical of intra-plate basalts, despite the fact that these rocks occur only 200 km east of the Andean Cordillera. Primary magmas were generated from a fertile garnet-bearing asthenospheric source at P=1.9-2.9 GPa and T=1420-1470°C. The data suggest a geodynamic model that implies sub-slab asthenosphere flow through a slab window, which started opening below this sector of South America 14 m.y. ago as a consequence of the collision of the Chile Ridge with the Chile Trench. The trailing edge of the Nazca Plate crossed below the Pali Aike area at 9-10 Ma, that is 6-5 m.y. before the onset of the volcanic activity. We hypothesize that this time delay resulted from changes in the kinematics of the South America-Scotia transform plate boundary which only allowed the Pali Aike magmas to rise after about 4 m.y.

  14. South America Delegation of the European Parliament Visits ESO's Paranal Observatory

    Science.gov (United States)

    2003-10-01

    Chaired by Dr. Rolf Linkohr , Members of the European Parliament Delegation for Relations with the Countries of South America and MERCOSUR visited ESO's Paranal Observatory on October 29-30, 2003. As the world's most advanced optical/infrared astronomical facility, the ESO Very Large Telescope (VLT) at Paranal is the flagship of European astronomy and a powerful expression of Europe's ambitions in this important area of fundamental research. It is also an outstanding example of the capabilities of Europe's high-technology industries. At the same time, the Paranal Observatory provides a model for international, scientific co-operation between Europe and Latin America, based on agreements between ESO and the Republic of Chile. The deputies were accompanied by the ESO Representative in Chile, Mr. Daniel Hofstadt . Upon arrival Wednesday afternoon, the Delegation was welcomed by Dr. Roberto Gilmozzi , Director of ESO Paranal. The distinguished visitors were impressed by the instrumentation park available to astronomical research at Paranal. During a nightly visit to the Control Centre of the observatory, they met with visiting astronomers and ESO staff and experienced some of the exciting research programmes now being carried out with the VLT at the front line of human knowledge. For Dr. Linkohr , Astrophysics means high-tech today and it has many ramifications in other areas of Science and Technology. "Europe cannot be better represented in Latin America - and in Chile in particular - than by such an outstanding scientific and technical achievement as the VLT" , he said. ESO has received support from EU programmes. "Current interactions between ESO and the EU have shown that first-rate windows of opportunities exist in high-tech developments, indispensable for our continued exploration of the unknown" , indicated Dr. Gilmozzi . The deputies are leaving Paranal today (Thursday October 30th), continuing to La Serena before travelling back to Santiago de Chile. The

  15. Effect of the lithospheric thermal state on the Moho interface: A case study in South America

    Science.gov (United States)

    Bagherbandi, Mohammad; Bai, Yongliang; Sjöberg, Lars E.; Tenzer, Robert; Abrehdary, Majid; Miranda, Silvia; Alcacer Sanchez, Juan M.

    2017-07-01

    Gravimetric methods applied for Moho recovery in areas with sparse and irregular distribution of seismic data often assume only a constant crustal density. Results of latest studies, however, indicate that corrections for crustal density heterogeneities could improve the gravimetric result, especially in regions with a complex geologic/tectonic structure. Moreover, the isostatic mass balance reflects also the density structure within the lithosphere. The gravimetric methods should therefore incorporate an additional correction for the lithospheric mantle as well as deeper mantle density heterogeneities. Following this principle, we solve the Vening Meinesz-Moritz (VMM) inverse problem of isostasy constrained by seismic data to determine the Moho depth of the South American tectonic plate including surrounding oceans, while taking into consideration the crustal and mantle density heterogeneities. Our numerical result confirms that contribution of sediments significantly modifies the estimation of the Moho geometry especially along the continental margins with large sediment deposits. To account for the mantle density heterogeneities we develop and apply a method in order to correct the Moho geometry for the contribution of the lithospheric thermal state (i.e., the lithospheric thermal-pressure correction). In addition, the misfit between the isostatic and seismic Moho models, attributed mainly to deep mantle density heterogeneities and other geophysical phenomena, is corrected for by applying the non-isostatic correction. The results reveal that the application of the lithospheric thermal-pressure correction improves the RMS fit of the VMM gravimetric Moho solution to the CRUST1.0 (improves ∼ 1.9 km) and GEMMA (∼1.1 km) models and the point-wise seismic data (∼0.7 km) in South America.

  16. Regional analysis on the occurrence of oral clefts in South America.

    Science.gov (United States)

    Poletta, F A; Castilla, E E; Orioli, I M; Lopez-Camelo, J S

    2007-12-15

    The aim of this work was to search for unequal birth prevalence rates (BPRs) of cleft lip +/- cleft palate (CL/P), and cleft palate only (CPO), among different geographic areas in South America, and to analyze phenotypic characteristics and associated risk factors in each identified cluster. Included were 5,128 CL/P cases, 1,745 CPO cases, and 3,712 controls (like-sexed, non-malformed liveborn infant, born immediately after a malformed one, in the same hospital), over 4,199,630 consecutive births. They were ascertained between 1967 and 2004, in 190 maternity hospitals of the ECLAMC (Estudio Colaborativo Latinoamericano de Malformaciones Congénitas) network, in 102 cities of all 10 South American countries. Non-predefined geographical areas with significantly unusual cleft BPRs were identified with Kulldorf and Nagarwalla's spatial scan statistic, employing number of cases and births, and exact location of each hospital. Expected values were cleft BPRs registered for the entire ECLAMC hospital network. Syndromic and non-syndromic clefts were considered for cluster analysis, and phenotypic characterization, while only non-syndromic for risk factor analysis. Seven clusters for CL/P, and four for CPO, with unusual BPRs were identified. CL/P cases in high BPR areas were more severe than elsewhere in the sample, similar to a previous ECLAMC report on microtia. For CL/P, high BPR clusters were associated with high altitude above sea level, Amerindian ancestry, and low socioeconomic strata; low BPR clusters showed association with African Black ancestry. Advanced maternal age, a recognized risk factor for CPO, was also associated with the only identified geographic cluster for CPO.

  17. Safe implementation of retroauricular robotic and endoscopic neck surgery in South America.

    Science.gov (United States)

    Lira, Renan Bezerra; Chulam, Thiago Celestino; Kowalski, Luiz Paulo

    2017-06-01

    In the last three decades, otolaryngology and head and neck oncological surgery have shown remarkable progress with the development of several modalities of endoscopic-assisted minimally invasive surgeries. More recently, the Da Vinci robotic surgery system has promoted the development of several surgical approaches with less morbidity and better cosmetic results, including the transaxillary and retroauricular approaches for thyroid surgery and neck dissections. In South America, there are several shortcomings regarding financial resources as well as the lack of support for innovation leading to a significant delay in adoption of numerous technological advances in medical practice. Despite these obstacles, we obtained training in transoral robotic surgery and neck procedures, and then decided to implement neck endoscopic and robotic surgery at our institution. We developed a collaborative training program with Yonsei University that, together with several local measures, allowed for a safe implementation. From June 2014 to December 2016, we have performed a total of 121 retroauricular neck surgeries, of which 65 were robotic-assisted and 56 were endoscopic assisted procedures, with a complication rate that seems to be comparable to conventional procedures in our experience and a smooth learning curve. Safety compliance has been continuously assessed. Aiming to develop and disseminate these techniques, we have ongoing collaborative work with Yonsei University faculty, to continue increasing our clinical experience, and we are now preparing the group and infrastructure to establish a local training program for South American surgeons. We have been presenting our results at national and international medical meetings and started to publish the preliminary results in peer reviewed medical journals. The emphasis is that a retroauricular approach is a therapeutic option to be considered, especially for young patients. Media exposure has been avoided so far. As expected

  18. The effect of paleoecology and paleobiogeography on stable isotopes of Quaternary mammals from South America

    Science.gov (United States)

    Domingo, Laura; Prado, José Luis; Alberdi, María Teresa

    2012-11-01

    The modern South American mammalian assemblage was determined by the closure of the Panama isthmus (˜2.7-3.1 Ma) and later on, by profound climatic and environmental fluctuations occurred during the Quaternary as well as by the appearance of humans in the continent. In the present study, stable isotope analyses (δ13C, δO and δO) have been carried out on Pleistocene-Holocene northern inmigrant and endemic taxa from a broad latitudinal and altitudinal distribution in South America with the purpose of characterizing their paleoecology and the effects of the paleobiogeographic distribution on stable isotope results. Equids and gomphotheres show a wide range of δ13C values going from woodlands to pure C4 grasslands. In the case of equids, Hippidion shows lower δ13C values than Equus in the Late Pleistocene, whereas, in the case of gomphotheres, Cuvieronius and Stegomastodon differ in their δ18O values on account on differences in their paleobiogeography with the former found in the Andean corridor and the latter dispersing through an eastern route. Isotope data of the rest of taxa (immigrant and endemic) are in general in good agreement with other previous isotopic and non-isotopic studies. The latitude threshold between mixed C3-C4 and pure C3 conditions have been pinpointed at ˜33°S in the Middle and the Late Pleistocene. Mammalian δ18O values are intimately related to latitudinal and altitudinal distribution, with the latter exerting an overriding influence independently of latitude. Calculated altitudinal gradients (between -0.23‰/100 m and -0.40‰/100 m) are within the range of modern gradients.

  19. Interannual variability of carbon monoxide emission estimates over South America from 2006 to 2010

    Science.gov (United States)

    Hooghiemstra, P. B.; Krol, M. C.; van Leeuwen, T. T.; van der Werf, G. R.; Novelli, P. C.; Deeter, M. N.; Aben, I.; Röckmann, T.

    2012-08-01

    We present the first inverse modeling study to estimate CO emissions constrained by both surface and satellite observations. Our 4D-Var system assimilates National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA/ESRL) Global Monitoring Division (GMD) surface and Measurements Of Pollution In The Troposphere (MOPITT) satellite observations jointly by fitting a bias correction scheme. This approach leads to the identification of a positive bias of maximum 5 ppb in MOPITT column-averaged CO mixing ratios in the remote Southern Hemisphere (SH). The 4D-Var system is used to estimate CO emissions over South America in the period 2006-2010 and to analyze the interannual variability (IAV) of these emissions. We infer robust, high spatial resolution CO emission estimates that show slightly smaller IAV due to fires compared to the Global Fire Emissions Database (GFED3) prior emissions. South American dry season (August and September) biomass burning emission estimates amount to 60, 92, 42, 16 and 93 Tg CO/yr for 2006 to 2010, respectively. Moreover, CO emissions probably associated with pre-harvest burning of sugar cane plantations in São Paulo state are underestimated in current inventories by 50-100%. We conclude that climatic conditions (such as the widespread drought in 2010) seem the most likely cause for the IAV in biomass burning CO emissions. However, socio-economic factors (such as the growing global demand for soy, beef and sugar cane ethanol) and associated deforestation fires, are also likely as drivers for the IAV of CO emissions, but are difficult to link directly to CO emissions.

  20. Dominant fault plane orientations of intermediate-depth earthquakes beneath South America

    Science.gov (United States)

    Warren, Linda M.

    2014-07-01

    The South American subduction zone exhibits considerable variation: the subduction angle alternates between flat and steep; the subducting plate has complex structures; and arc volcanism in the overlying plate has gaps. I investigate the effect of these differences in incoming plate structure and slab geometry on intermediate-depth earthquakes, specifically their fault orientations and rupture characteristics, and find that slab geometry has the largest impact on fault orientation. I use rupture directivity to estimate rupture direction and rupture velocity and to distinguish the fault plane from the auxiliary plane of the focal mechanism. From analysis of 163 large (Mw≥5.7) intermediate-depth (60-360 km depth) earthquakes from along the length of South America, estimated rupture azimuths and plunges show no trends, appearing to be randomly distributed on the determined population of fault plane orientations, and a majority of earthquakes are made up of multiple subevents. As seen in other subduction zones, subduction segments descending at normal angles have predominantly subhorizontal faults. Flat slab segments also have a dominant fault orientation, but those earthquakes slip along the conjugate nodal plane of the focal mechanism. In strongly curved slab segments, such as at the downdip edge of flat segments where the slab resubducts, earthquakes may slip along either nodal plane orientation. While both fault orientations could be consistent with the reactivation of fossil outer rise faults, the fault orientations are also consistent with expectations for newly created faults in agreement with the ambient stress field. Fault reactivation alone does not explain why different fault orientations are active in segments with different geometries, so the preferred explanation for having regionally consistent fault orientations is that they minimize the total work of the system. The previously observed predominance of subhorizontal faults appears to be a consequence

  1. The Archeomagnetic field in South America: Present status and perspectives (Invited)

    Science.gov (United States)

    Hartmann, G. A.; Trindade, R. I.; Gallet, Y.; Poletti, W.; Begnini, G. S.; Genevey, A.; Legoff, M.

    2013-12-01

    Geomagnetic field variations over decadal to millennial timescales can be determined from direct (i.e. observatory) and indirect (e.g. from archeological artifacts and volcanics) sources. Before the observatory era, the recovery of these variations is however still strongly penalized by the very uneven both geographical and temporal distributions of the available archeo/paleomagnetic dataset. In particular, the southern hemisphere contributes with only ~3% of the global archeomagnetic database. Moreover, most of these data present restrictions due to their poor experimental reliability and to the lack of good age control. Therefore, new intensity and directional data from the southern hemisphere are strongly requested for the next generation of archeomagnetic field models. In this presentation, we will report on intensity and inclination results obtained from different regions in Brazil. A collection of twenty-three site-mean archeointensity data were obtained by our team from architectural brick fragments dated to the past 500 years from Northeast and Southeast Brazil. This dataset was complemented by a series of new results from South Brazil. In addition, we also obtained inclination data, after reconstructing the firing position of the ancient bricks from modern analogs of historical brickyards. Thirteen site-mean inclination results dated to between 1790 AD and 1950 AD and five inclination results spanning the 1590-1920 AD time interval were so determined from Southeast and Northeast Brazil, respectively. Altogether, our data, which are geographically distributed over more than 20 degrees in latitude, allow us to discuss the large-scale influence in Brazil and South America of non-dipolar features of the geomagnetic field during the past few centuries.

  2. Correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

    Science.gov (United States)

    Fu, X. W.; Zhang, H.; Lin, C.-J.; Feng, X. B.; Zhou, L. X.; Fang, S. X.

    2015-01-01

    Correlation analyses between atmospheric mercury (Hg) and other trace gases are useful for identification of sources and constraining regional Hg emissions. Emissions of Hg in Asia contribute significantly to the global budget of atmospheric Hg. However, due to the lack of reliable data on the source strength, large uncertainties remain in the emission inventories of Hg in Asia. In the present study, we calculated the correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 for mainland China, South Asia, the Indochinese Peninsula, and Central Asia using the ground-based observations at three remote sites in northwestern and southwestern China, and applied these values to estimate GEM emissions in the four source regions. The geometric mean GEM / CO correlation slopes for mainland China, South Asia, the Indochinese Peninsula, and Central Asia were 7.3 ± 4.3, 7.8 ± 6.4, 7.8 ± 5.0, and 13.4 ± 9.5 pg m-3 ppb-1, respectively, and values in the same source regions were 33.3 ± 30.4, 27.4 ± 31.0, 23.5 ± 15.3, and 20.5 ± 10.0 pg m-3 ppb-1 for the GEM / CH4 correlation slopes, respectively. The geometric means of GEM / CO2 correlation slopes for mainland China, South Asia, and Central Asia were 240 ± 119, 278 ± 164, 315 ± 289 pg m-3 ppm-1, respectively. These values were the first reported correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 in four important source regions of Asia, not including the GEM / CO ratios in mainland China. The correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 in Asia were relatively higher than those observed in Europe, North America, and South Africa, which may highlight GEM emissions from non-ferrous smelting, large-scale and artisanal mercury and gold production, natural sources, and historically deposited mercury (re-emission) in Asia. Using the observed GEM / CO and GEM / CO2 slopes, and the recently reported emission inventories of CO and CO2, the annual GEM emissions in mainland China, South Asia, the Indochinese

  3. Dispersal of Pleistocene Equus (Family Equidae) into South America and Calibration of GABI 3 Based on Evidence from Tarija, Bolivia

    OpenAIRE

    Bruce J Macfadden

    2013-01-01

    The dispersal of Equus into South America during the Great American Biotic Interchange (GABI) represented a major event for Pleistocene land-mammal age chronology on that continent. It has been argued that this dispersal occurred during the late Pleistocene, ∼0.125 Ma, and it defines the base of the Lujanian South American Land Mammal Age (SALMA). In this scenario, Equus dispersed during the fourth and latest recognized phase of the interchange, i.e., GABI 4. Although Equus was widely distrib...

  4. The coexistence of peace and conflict in South America: toward a new conceptualization of types of peace

    Directory of Open Access Journals (Sweden)

    Jorge Mario Battaglino

    2012-12-01

    Full Text Available South America's predominant democratic regimes and its increasing interdependence on regional trade have not precluded the emergence of militarized crises between Colombia and Venezuela or the revival of boundary claims between Chile and Peru. This way, how can we characterize a zone that, in spite of its flourishing democracy and dense economic ties, remain involved in territorial disputes for whose resolution the use of force has not yet been discarded? This article contends that existing classifications of zones of peace are not adequate to explain this unusual coexistence. Thus, its main purpose is to develop a new analytical category of regional peace for assessing this phenomenon: the hybrid peace. It aims to research the evolution of security systems in South America during the previous century and build a new, threefold classification of peace zones: negative peace zones, hybrid peace zones, and positive peace zones.

  5. Artificial neural networks and multiple linear regression model using principal components to estimate rainfall over South America

    Science.gov (United States)

    Soares dos Santos, T.; Mendes, D.; Rodrigues Torres, R.

    2016-01-01

    Several studies have been devoted to dynamic and statistical downscaling for analysis of both climate variability and climate change. This paper introduces an application of artificial neural networks (ANNs) and multiple linear regression (MLR) by principal components to estimate rainfall in South America. This method is proposed for downscaling monthly precipitation time series over South America for three regions: the Amazon; northeastern Brazil; and the La Plata Basin, which is one of the regions of the planet that will be most affected by the climate change projected for the end of the 21st century. The downscaling models were developed and validated using CMIP5 model output and observed monthly precipitation. We used general circulation model (GCM) experiments for the 20th century (RCP historical; 1970-1999) and two scenarios (RCP 2.6 and 8.5; 2070-2100). The model test results indicate that the ANNs significantly outperform the MLR downscaling of monthly precipitation variability.

  6. Campylobacter y campylobacteriosis: una mirada desde América del Sur Campylobacter and campylobacteriosis: a view from South America

    Directory of Open Access Journals (Sweden)

    Heriberto Fernández

    2011-03-01

    Full Text Available Las especies termotolerantes de Campylobacter han adquirido gran importancia en la salud pública, por ser considerados agentes de diarrea infecciosa para el ser humano. En esta breve revisión se presenta información sobre aspectos epidemiológicos, clínicos y bacteriológicos de campylobacteriosis en América del Sur. Asimismo, se señalan algunas diferencias con relación a su presentación en países industrializados.The thermotolerant species of Campylobacter have become very important in public health, especially as agents of infectious diarrhea in human beings. In this brief revision we present part of the available information generated in South America about epidemiological, clinical and bacteriological aspects of campylobacteriosis and we identify some differences between the observed and documented campylobacteriosis in South America compared to those described in industrialized countries.

  7. The Paleoparasitology in Brazil and Findings in Human Remains from South America: A Review.

    Science.gov (United States)

    Novo, Shênia Patrícia Corrêa; Ferreira, Luiz Fernando

    2016-10-01

    The review article presents some of the history of how paleoparasitology started in Brazil, making highlight the great responsible Dr. Luiz Fernando Ferreira and Dr. Adauto Araújo, the trajectory of paleoparasitology in Brazil since 1978 and its performance in science to the present day. In sequence, it is made a presentation of parasitological findings on human remains found in archaeological sites in South America, highlighting Brazil, Argentina, Chile, and Peru, where major discoveries have occurred. Many of the parasites found in archaeological material and mentioned in this review went out of Africa with the peopling of Europe and from there they dispersed around the world, where climatic conditions allow the transmission. However, humans have acquired other parasites of animals, since humans invaded new habitats or creating new habits adopting new technologies, thus expanding its range of influence on the environment. Thus, this review article is finalized with information that explain the importance of these findings in the interaction between parasites, human host, and ambient.

  8. Late-glacial elevated dust deposition linked to westerly wind shifts in southern South America

    Science.gov (United States)

    Vanneste, Heleen; de Vleeschouwer, François; Martínez-Cortizas, Antonio; von Scheffer, Clemens; Piotrowska, Natalia; Coronato, Andrea; Le Roux, Gaël

    2015-07-01

    Atmospheric dust loadings play a crucial role in the global climate system. Southern South America is a key dust source, however, dust deposition rates remain poorly quantified since the last glacial termination (~17 kyr ago), an important timeframe to anticipate future climate changes. Here we use isotope and element geochemistry in a peat archive from Tierra del Fuego, to reconstruct atmospheric dust fluxes and associated environmental and westerly wind changes for the past 16.2 kyr. Dust depositions were elevated during the Antarctic Cold Reversal (ACR) and second half of the Younger Dryas (YD) stadial, originating from the glacial Beagle Channel valley. This increase was most probably associated with a strengthening of the westerlies during both periods as dust source areas were already available before the onset of the dust peaks and remained present throughout. Congruent with glacier advances across Patagonia, this dust record indicates an overall strengthening of the wind belt during the ACR. On the other hand, we argue that the YD dust peak is linked to strong and poleward shifted westerlies. The close interplay between dust fluxes and climatic changes demonstrates that atmospheric circulation was essential in generating and sustaining present-day interglacial conditions.

  9. a Marine Record of Holocene Climate Events in Tropical South America

    Science.gov (United States)

    Haug, G. H.; Günther, D.; Hughen, K. A.; Peterson, L. C.; Röhl, U.

    2002-12-01

    Metal concentration data (Ti, Fe) from the anoxic Cariaco Basin off the Venezuelan coast record with subdecadal to seasonal resolution variations in the hydrological cycle over tropical South America during the last 14 ka. Following a dry Younger Dryas, a period of increased precipitation and riverine discharge occurred during the Holocene `thermal maximum'. Since ~5.4 ka, a trend towards drier conditions is evident from the data, with high amplitude fluctuations and precipitation minima during the time interval 3.8 to 2.8 ka and during the `Little Ice Age'. O pronouced increase in precipitation coincides with the phase sometimes referred to as the `Medieval Warm Period'. These regional changes in precipitation are best explained by shifts in the mean latitude of the Atlantic Intertropical Convergence Zone (ITCZ), potentially driven by Pacific-based climate variability. The variations recorded in Cariaco Basin sediments coincide with events in societal evolution that have been suggested previously to be motivated by environmental change. Regionally, the Cariaco record supports the notion that the collapse of this civilization between 800 and 1000 AD coincided with an extended period of drier conditions, implying that the rapid growth of Mayan culture from 600 to 800 AD may have resulted in a population operating at the fringes of the environment's carrying capacity. The Cariaco Basin record also hints at tropical climate events similar in timing to high latitude changes in the North Atlantic often invoked as pivotal to societal developments in Europe.

  10. Trends and Spatial Patterns of Drought Affected Area in Southern South America

    Directory of Open Access Journals (Sweden)

    Juan A. Rivera

    2014-09-01

    Full Text Available Based on 56 rainfall stations, which cover the period 1961–2008, we analyzed the presence of trends in the drought-affected area over southern South America (SSA at different time scales. In order to define drought conditions, we used the standardized precipitation index, which was calculated on time scales of 1, 3, 6, 9 and 12 months. The trends were estimated following both a linear and a non-linear approach. The non-linear approach was based on the residual of the empirical mode decomposition, a recently proposed methodology, which is robust in presence of non-stationary data. This assessment indicates the existence of reversals in the trends of the drought affected, area around the 1990s, from decreasing trends during the first period to increasing trends during the recent period. This is indicative of the existence of a low-frequency variability that modulates regional precipitation patterns at different temporal scales, and warns about possible future consequences in the social and economic sectors if trends towards an increase in the drought affected area continue.

  11. Late-glacial elevated dust deposition linked to westerly wind shifts in southern South America.

    Science.gov (United States)

    Vanneste, Heleen; De Vleeschouwer, François; Martínez-Cortizas, Antonio; von Scheffer, Clemens; Piotrowska, Natalia; Coronato, Andrea; Le Roux, Gaël

    2015-01-01

    Atmospheric dust loadings play a crucial role in the global climate system. Southern South America is a key dust source, however, dust deposition rates remain poorly quantified since the last glacial termination (~17 kyr ago), an important timeframe to anticipate future climate changes. Here we use isotope and element geochemistry in a peat archive from Tierra del Fuego, to reconstruct atmospheric dust fluxes and associated environmental and westerly wind changes for the past 16.2 kyr. Dust depositions were elevated during the Antarctic Cold Reversal (ACR) and second half of the Younger Dryas (YD) stadial, originating from the glacial Beagle Channel valley. This increase was most probably associated with a strengthening of the westerlies during both periods as dust source areas were already available before the onset of the dust peaks and remained present throughout. Congruent with glacier advances across Patagonia, this dust record indicates an overall strengthening of the wind belt during the ACR. On the other hand, we argue that the YD dust peak is linked to strong and poleward shifted westerlies. The close interplay between dust fluxes and climatic changes demonstrates that atmospheric circulation was essential in generating and sustaining present-day interglacial conditions.

  12. Southern promises: a snapshot of the microbiology research landscape in South America based on bibliometric data.

    Science.gov (United States)

    Nai, Corrado

    2017-09-01

    Scientists have a single currency for productivity and impact: published articles. In an effort to map the global research landscape in microbiology, and to obviate the current lack of bibliometric analysis in the field, FEMS-the Federation of European Microbiological Societies-generated a dataset encompassing an exhaustive, worldwide list of microbiology studies for 2013-14, which further includes information as author affiliation, funding agency and number of citations. The manually curated database is useful in assessing the impact and regional productivity of microbiology research at different levels. Here, the data for microbiology research in South America are presented and discussed in detail. Based on the analysis, it emerged that despite great degrees of variation between number of published articles among the countries, a more levelled research productivity was observed when considering further dimensions like population size or number of research institutes. Normalised productivity and impact increase in countries with a 'central research hub', i.e. an institute or university producing a substantial portion of the national output (15% or more). From these observations, a possible strategy to increase impact and productivity in (microbiology) research for emerging countries is outlined. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Trichinella patagoniensis n. sp. (Nematoda), a new encapsulated species infecting carnivorous mammals in South America.

    Science.gov (United States)

    Krivokapich, Silvio J; Pozio, Edoardo; Gatti, Graciana M; Prous, Cinthia L Gonzalez; Ribicich, Mabel; Marucci, Gianluca; La Rosa, Giuseppe; Confalonieri, Viviana

    2012-09-01

    Until a few years ago, Trichinella spiralis was the only taxon of the genus Trichinella detected in both domestic and wild animals of South America. Recently, a new genotype, named Trichinella T12, was identified in cougars (Puma concolor) from Argentina, on the basis of molecular studies using mitochondrial and nuclear ribosomal markers. In the present study, cross-breeding experiments indicated that Trichinella T12 is reproductively isolated from all other encapsulated Trichinella spp. and suggested that it is biologically more similar to Trichinella britovi and Trichinella murrelli than to the other encapsulated species/genotypes. Biological assays revealed that the reproductive capacity index of Trichinella T12 was ~4 and >2000 times lower than those of T. spiralis in mice and rats, respectively. The reproductive capacity index of Trichinella T12 in domestic pigs ranged from 0.0 to 0.05. Larvae parasitising the muscles of carnivores were infective to mice after freezing at -5°C for 3 months, but they lost infectivity after freezing at -18°C for 1 week. The region within the rDNA, known as the expansion segment V, showed a unique sequence which differs from those of all other known Trichinella spp./genotypes. The biological, geographical and molecular data support the classification of the genotype Trichinella T12 as a new species widespread in the Neotropical region, for which we propose the name Trichinella patagoniensis n. sp.

  14. A scenario elicitation methodology to identify the drivers of electricity infrastructure cost in South America

    Science.gov (United States)

    Moksnes, Nandi; Taliotis, Constantinos; Broad, Oliver; de Moura, Gustavo; Howells, Mark

    2017-04-01

    Developing a set of scenarios to assess a proposed policy or future development pathways requires a certain level of information, as well as establishing the socio-economic context. As the future is difficult to predict, great care in defining the selected scenarios is needed. Even so it can be difficult to assess if the selected scenario is covering the possible solution space. Instead, this paper's methodology develops a large set of scenarios (324) in OSeMOSYS using the SAMBA 2.0 (South America Model Base) model to assess long-term electricity supply scenarios and applies a scenario-discovery statistical data mining algorithm, Patient Rule Induction Method (PRIM). By creating a multidimensional space, regions related to high and low cost can be identified as well as their key driver. The six key drivers are defined a priori in three (high, medium, low) or two levers (high, low): 1) Demand projected from GDP, population, urbanization and transport, 2) Fossil fuel price, 3) Climate change impact on hydropower, 4) Renewable technology learning rate, 5) Discount rate, 6) CO2 emission targets.

  15. Monitoring strategy for eight amphibian species in French Guiana, South America.

    Science.gov (United States)

    Courtois, Elodie A; Devillechabrolle, Jennifer; Dewynter, Maël; Pineau, Kévin; Gaucher, Philippe; Chave, Jérôme

    2013-01-01

    Although dramatic amphibian declines have been documented worldwide, only few of such events have been quantitatively documented for the tropical forests of South America. This is due partly to the fact that tropical amphibians are patchily distributed and difficult to detect. We tested three methods often used to monitor population trends in amphibian species in a remote lowland tropical forest of French Guiana. These methods are capture-mark-recapture (CMR), estimation of the number of calling males with repeated counts data and distance sampling, and rates of occupancy inferred by presence/absence data. We monitored eight diurnal, terrestrial amphibian species including five Dendrobatidae and three Bufonidae. We found that CMR, the most precise way of estimating population size, can be used only with two species in high density patches where the recapture rate is high enough. Only for one of the species (Dendrobates tinctorius), a low coefficient of variation (CV = 0.19) can be achieved with 15 to 20 capture events. For dendrobatid species with day-calling males, audio surveys yield a better probability of detection with only 8 audio surveys needed; quantitative estimates can be achieved by computing the number of calling males inferred from audio counts or distance sampling analysis. We therefore suggest that an efficient monitoring protocol for Neotropical amphibian species should include a combination of sighting and audio techniques, and we discuss the need of implementing a large-scale monitoring in order to provide a baseline for comparison with future changes.

  16. Monitoring strategy for eight amphibian species in French Guiana, South America.

    Directory of Open Access Journals (Sweden)

    Elodie A Courtois

    Full Text Available Although dramatic amphibian declines have been documented worldwide, only few of such events have been quantitatively documented for the tropical forests of South America. This is due partly to the fact that tropical amphibians are patchily distributed and difficult to detect. We tested three methods often used to monitor population trends in amphibian species in a remote lowland tropical forest of French Guiana. These methods are capture-mark-recapture (CMR, estimation of the number of calling males with repeated counts data and distance sampling, and rates of occupancy inferred by presence/absence data. We monitored eight diurnal, terrestrial amphibian species including five Dendrobatidae and three Bufonidae. We found that CMR, the most precise way of estimating population size, can be used only with two species in high density patches where the recapture rate is high enough. Only for one of the species (Dendrobates tinctorius, a low coefficient of variation (CV = 0.19 can be achieved with 15 to 20 capture events. For dendrobatid species with day-calling males, audio surveys yield a better probability of detection with only 8 audio surveys needed; quantitative estimates can be achieved by computing the number of calling males inferred from audio counts or distance sampling analysis. We therefore suggest that an efficient monitoring protocol for Neotropical amphibian species should include a combination of sighting and audio techniques, and we discuss the need of implementing a large-scale monitoring in order to provide a baseline for comparison with future changes.

  17. Report on the results of the ninth medical examination of atomic bomb survivors in South America

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Michiya [Hiroshima Atomic Bomb Hospital (Japan); Hiyama, Keiko; Matsuo, Kakaru; Yamamoto, Hiroki; Nishida, Masashi; Sasaki, Yoshinobu

    2001-06-01

    The results of the ninth medical examination are reported. Atomic bomb survivors who had emigrated to South America as of November 2000 totaled 180 (153 to Brazil, 4 to Paraguay, 7 to Bolivia, 13 to Argentina, and 3 to Peru). Eighty persons (44.4%) were examined (62 in Brazil, 2 in Paraguay, 6 in Bolivia, 7 in Argentina, and 3 in Peru). The mean age of the males was 71.3 years, and the mean age of the females was 69.7 years. They had hypertension (24.1%), diabetes (10.1%), cancer (8.9%), heart disease (7.6%), and thyroid disease (2.5%). The most common manifestations of illness were fatigue (69.6%), loss of vigor (65.8%), taking medicine (55.7%), and heat intolerance (53.2%). The incident rates of electrocardiographic abnormalities and urine, blood, and biochemical tests abnormalities were almost the same as at the previous examination, and there was no change in the percentage of those who required detailed tests and treatment. When independence in daily life was judged by the criteria of the nursing care insurance system, 68 persons were judged ''independent'', and 7 persons ''handicapped.'' (K.H.)

  18. Ozone depletion and UVB radiation: impact on plant DNA damage in southern South America.

    Science.gov (United States)

    Rousseaux, M C; Ballaré, C L; Giordano, C V; Scopel, A L; Zima, A M; Szwarcberg-Bracchitta, M; Searles, P S; Caldwell, M M; Díaz, S B

    1999-12-21

    The primary motivation behind the considerable effort in studying stratospheric ozone depletion is the potential for biological consequences of increased solar UVB (280-315 nm) radiation. Yet, direct links between ozone depletion and biological impacts have been established only for organisms of Antarctic waters under the influence of the ozone "hole;" no direct evidence exists that ozone-related variations in UVB affect ecosystems of temperate latitudes. Indeed, calculations based on laboratory studies with plants suggest that the biological impact of ozone depletion (measured by the formation of cyclobutane pyrimidine dimers in DNA) is likely to be less marked than previously thought, because UVA quanta (315-400 nm) may also cause significant damage, and UVA is unaffected by ozone depletion. Herein, we show that the temperate ecosystems of southern South America have been subjected to increasingly high levels of ozone depletion during the last decade. We found that in the spring of 1997, despite frequent cloud cover, the passages of the ozone hole over Tierra del Fuego (55 degrees S) caused concomitant increases in solar UV and that the enhanced ground-level UV led to significant increases in DNA damage in the native plant Gunnera magellanica. The fluctuations in solar UV explained a large proportion of the variation in DNA damage (up to 68%), particularly when the solar UV was weighted for biological effectiveness according to action spectra that assume a sharp decline in quantum efficiency with increasing wavelength from the UVB into the UVA regions of the spectrum.

  19. First evidence of pre-Hispanic dentistry in South America - Insights from Cusco, Peru.

    Science.gov (United States)

    Ortiz, A; Torres Pino, E C; Orellana González, E

    2016-04-01

    Intentional dental modification (IDM) derived from archeological or ethnographic contexts has been extensively documented across the globe. Despite the wealth of information on IDM for personal ornamentation and ritualistic purposes, evidence of IDM for therapeutic reasons among early Native Americans is poorly known and limited to a handful of cases. We report two upper canines from two pre-Hispanic individuals dated to the Late Horizon Period from Cusco (Peru), each showing a conical perforation on its incisal surface. Analyses were performed using traditional radiography, computed tomography and scanning electron microscopy. The depth and symmetrical location of the perforations at the center of the crown suggest that these two teeth were artificially drilled, rather than affected by taphonomic factors. The poor oral health of the individuals, the location of the perforations on the incisal surface, and evidence of intentional manipulation of the pulp chambers (as supported by their overall morphology and presence of striations and deep marks along the walls of the perforations) provide a strong case for the occurrence of prehistoric dentistry in the New World. The two canine teeth reported here represent the first pre-Columbian examples of IDM likely performed to ameliorate a dental pathology (presumably associated with the infection of the dental pulp) found in Peru and in the rest of South America.

  20. Comparison of GNSS integrated water vapor and NWM reanalysis data over Central and South America

    Science.gov (United States)

    Fernández, Laura Isabel; Natali, Maria Paula; Meza, Amalia; Mendoza, Luciano; Bianchi, Clara

    2016-07-01

    Integrated water vapor (IWV) derived from Global Navigation Satellite Systems (GNSS) and Numerical Weather Models (NWM) reanalysis data were compared in order to assess the consistency between the different datasets over the extended geographical region of Central and South America. The analysis was performed for the seven years period between 2007 and 2013. We analyzed two different NWM: the European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis data (ERA Interim) and the Modern-Era Retrospective analysis for Research and Applications (MERRA) from the National Aeronautics and Space Administration (NASA). The statistical analysis of the differences was performed in 110 GNSS sites (GPS + GLONASS), although the most interesting results came from the 73 sites which have more than 5 years of data. The selected area involves different climate types, from polar to tropical, and it is characterized by large temporal variability of the integrated total humidity content. Moreover, the scarce coverage of operational radio sounding stations is noticeable in large areas of the selected region; hence the contribution of IWV-GNSS is essential to improve the weather understanding. Considering that the atmospheric water vapor has a highly variable and complex distribution which knowledge is essential for weather prediction and local meteorological studies. This study aims to provide IWV-GNSS observations able to be assimilated by operational weather centers, for both prediction and simulation, as well for improving regional modeling.

  1. Coleopterans associated with plants that form phytotelmata in subtropical and temperate Argentina, South America.

    Science.gov (United States)

    Campos, Raúl E; Fernández, Liliana A

    2011-01-01

    A list of the most common plants that form phytotelmata and their associated coleopterans (aquatic, semi-aquatic and terrestrial) from the northeastern subtropical and temperate area of Argentina, South America with biological and behavioral observations is presented in this study. Species of Poaceae (n = 3), Bromeliaceae (5), Apiaceae (6), Araceae (2), Urticaceae (1), Marantaceae (1), Arecaceae (1), Dipsacaceae (1) and Cyperaceae (1) were identified as phytotelmata. Aquatic species of Scirtidae (2), Dytiscidae (2), and Hydrophilidae (4), semi-aquatic Chelonariidae (2), and terrestrial species of Carabidae (3), Staphylinidae (5), Histeridae (1), Elateridae (1), Cantharidae (1), Cleridae (1), Tenebrionidae (1), Meloidae (1), Anthicidae (1), Chrysomelidae (3), Curculionidae (7) and Apionidae (1) were identified from six species of Eryngium L. (Apiales: Apiaceae), two species of Guadua Kunth (Poales: Poaceae), Aechmea distichantha Lemaire (Poales: Bromeliaceae), and from fallen leaves of Euterpe edulis Martius (Arecales: Arecaceae) from the temperate and subtropical area. The highest species richness was recorded in Eryngium phytotelmata. Fifteen species of beetles inhabit Eryngium cabrerae Pontiroli, 11 in E. horridum Malme, 7 in E. stenophyllum Urban, 4 in E. aff. serra Chamisso and Schlechtendal., 3 in E. elegans Chamisso and Schlechtendal, 2 in E. eburneum Decne and E. pandanifolium Chamisso and Schlechtendal. From bamboo, 6 species of coleopterans were collected from Guadua trinii (Nees) Nees ex Ruprecht and 4 from G. chacoensis (Rojas) Londoño and Peterson. Three species of aquatic coleopterans were recorded from A. distichantha and only one from E. edulis.

  2. Science Teacher Education in South America: The Case of Argentina, Colombia and Chile

    Science.gov (United States)

    Cofré, Hernán; González-Weil, Corina; Vergara, Claudia; Santibáñez, David; Ahumada, Germán; Furman, Melina; Podesta, María E.; Camacho, Johanna; Gallego, Rómulo; Pérez, Royman

    2015-02-01

    In this review, the main characteristics of science teacher education in three countries in South America, namely Argentina, Chile and Colombia, are examined. Although reforms toward constructivist and inquiry-based teaching in science instruction have been made in each of the three reviewed countries, each country demonstrates limitations in the implementation of teacher education that aims at those objectives. None of these countries have rigorous selection criteria for candidates for science teacher education programs, although each has some type of certification or test requirement before entry into the public education system is permitted. The three countries have similar teacher training programs, with instruction programs lasting between 4 and 5 years; programs entail both disciplinary instruction and pedagogical instruction that starts in the first year. Data from the three countries show that a high percentage of instruction in the training programs is devoted to general pedagogy with less instruction time devoted to specific preparation for teaching science. Disciplinary instruction accounts for nearly 50 % of the instruction program among secondary teachers. Training in other subjects such as nature of science, history of science and scientific inquiry is poorly developed. In general, there are few opportunities for research on practicum, as these opportunities tend to occur at the end of the training program. The generation of instruction standards by governments as well as the increase in the number of scholars dedicated to the investigation of science education and the education of science teachers suggests that some of these shortcomings could be remedied in the future.

  3. Discovering potential sources of emerging pathogens: South America is a reservoir of generalist avian blood parasites.

    Science.gov (United States)

    Moens, Michaël A J; Pérez-Tris, Javier

    2016-01-01

    Generalist pathogens are capable of infecting a wide range of host species, and may pose serious disease emergence threats if accidentally moved outside their native areas. To date little effort has been devoted to identifying geographic areas that may act as reservoirs of generalist pathogens. According to current theory, where host diversity is high, parasite specialisation in one host species may be penalised by reduced host availability, while generalist parasites may benefit from the exploitation of various host species. Therefore natural selection could favor generalist parasites where host diversity is high. Here we explored if, in a highly diverse bird community in Ecuador, a generalist strategy is promoted among local Haemoproteus and Plasmodium blood-borne parasites compared with similar parasite communities throughout the world. We reconstructed the phylogenetic relationships of every parasite lineage in order to understand the evolution of host specificity in this megadiverse area. We found high levels of host generalisation for both parasite genera, and the mean host range of the Haemoproteus community in Ecuador was significantly higher than other parasite communities in other areas outside the Neotropics. Generalist Haemoproteus parasites in this bird community had diverse phylogenetic ancestry, were closely related to specialist parasites and were apparently endemic to the Amazon, showing that different parasites have independently evolved into host generalists in this region. Finally we show that Haemoproteus communities in Ecuador and South America are more generalist than in temperate areas, making this continent a hotspot of generalist Haemoproteus parasites for wild birds.

  4. A history of Proterozoic terranes in southern South America: From Rodinia to Gondwana

    Directory of Open Access Journals (Sweden)

    C. Casquet

    2012-03-01

    Full Text Available The role played by Paleoproterozoic cratons in southern South America from the Mesoproterozoic to the Early Cambrian is reconsidered here. This period involved protracted continental amalgamation that led to formation of the supercontinent Rodinia, followed by Neoproterozoic continental break-up, with the consequent opening of Clymene and Iapetus oceans, and finally continental re-assembly as Gondwana through complex oblique collisions in the Late Neoproterozoic to Early Cambrian. The evidence for this is based mainly on a combination of precise U-Pb SHRMP dating and radiogenic isotope data for igneous and metamorphic rocks from a large area extending from the Rio de la Plata craton in the east to the Argentine Precordillera in the west and as far north as Arequipa in Peru. Our interpretation of the paleogeographical and geodynamic evolution invokes a hypothetical Paleoproterozoic block (MARA embracing basement ultimately older than 1.7 Ga in the Western Sierras Pampeanas (Argentina, the Arequipa block (Peru, the Rio Apa block (Brazil, and probably also the Paraguaia block (Bolivia.

  5. Late Quaternary glaciation history of Isla de los Estados, southeasternmost South America

    Science.gov (United States)

    Möller, Per; Hjort, Christian; Björck, Svante; Rabassa, Jorge; Ponce, Juan Federico

    2010-05-01

    Isla de los Estados is a mountainous island southeast of Tierra del Fuego, in southernmost South America. Its central and eastern parts have an alpine topography, transected by U-shaped valleys, small, partly over-deepened fjords, and a multitude of abandoned cirques, all associated with extensive former local glaciations. Traces of glacial erosion generally reach 400-450 m a.s.l., and above that trimline a distinct sharp-edged nunatak derived landscape is present. The westernmost part of the island has a lower, more subdued topography, reflecting its "softer" geology but possibly also over-running and erosion by mainland-derived ice streams. The present study concentrated on glacigenic sediment sequences exposed along coastal erosional cliffs. A combination of OSL and 14C datings show that these sediments mostly date from the latest (Wisconsinan/Weichselian) glacial cycle, i.e. from the last ca. 100 ka with the oldest (glaciolacustrine) deposits possibly as old as 90-80 ka. The upper parts of overlying tills, with associated lateral and terminal moraines from glaciers that expanded onto an eustatically exposed dry shelf north of the island, date from the last global glacial maximum (LGM). Radiocarbon ages of peat and lake sediments indicate that deglaciation began 17-16 cal ka BP.

  6. Care of patients with Huntington's disease in South America: a survey

    Directory of Open Access Journals (Sweden)

    Ricardo Oliveira Horta Maciel

    2013-06-01

    Full Text Available Huntington's disease (HD is a rare neurodegenerative disease with a multitude of symptoms, which requires access to specialized multidisciplinary care for adequate management. The aim of this study was to survey the characteristics of care in various HD centers in South America (SA. Methods A questionnaire was sent to 24 centers involved in the care for HD patients in SA. Results Of the total 24 centers, 19 (79.2% are academic units. The majority of centers (62.5% are general movement disorders clinics. Multidisciplinary care is available in 19 (79.2% centers and in 20 (83.3% care is provided free of charge. Genetic testing and counseling are available in 25 and 66.6% of centers, respectively. The majority of centers (83.3% have no institutional support for end-stage care. Conclusions Although HD centers in SA are committed to providing multidisciplinary care, access to genetic counseling and end-stage care are lacking in most centers.

  7. Care of patients with Huntington's disease in South America: a survey.

    Science.gov (United States)

    Maciel, Ricardo Oliveira Horta; Cardoso, Francisco Eduardo Costa; Chaná-Cuevas, Pedro; Cosentino, Carlos; Fernández, William; Rieder, Carlos R M; Serrano-Dueñas, Marcos; Weiser, Roberto

    2013-06-01

    Huntington's disease (HD) is a rare neurodegenerative disease with a multitude of symptoms, which requires access to specialized multidisciplinary care for adequate management. The aim of this study was to survey the characteristics of care in various HD centers in South America (SA). Methods A questionnaire was sent to 24 centers involved in the care for HD patients in SA. Results Of the total 24 centers, 19 (79.2%) are academic units. The majority of centers (62.5%) are general movement disorders clinics. Multidisciplinary care is available in 19 (79.2%) centers and in 20 (83.3%) care is provided free of charge. Genetic testing and counseling are available in 25 and 66.6% of centers, respectively. The majority of centers (83.3%) have no institutional support for end-stage care. Conclusions Although HD centers in SA are committed to providing multidisciplinary care, access to genetic counseling and end-stage care are lacking in most centers.

  8. Seasonal-to-Interannual Variability of Southeastern South America in CMIP5 Decadal Hindcasts

    Science.gov (United States)

    Gonzalez, P. L.; Goddard, L. M.

    2011-12-01

    To face the increasing demand of near-term climate information, CMIP5 has designed a set of decadal hindcasts that explore the effect of initializing the models with information about the current state of the climate system. The idea is that some skill for the next year-to-decade may be gained if one can predict aspects of the natural internal variability of the climate system in addition to the anthropogenic trend. Preliminary results suggest that these hindcasts have some additional skill in the North Atlantic Ocean, which is likely associated with Atlantic multi-decadal variability, and in the tropical Pacific Ocean, which may reflect the decadal-scale component of ENSO. Southeastern South America (SESA) is a potentially interesting region to explore in these hindcasts, especially for precipitation. Over the 20th century this region experienced large trends, showed decadal-scale variability, and also exhibited strong seasonal-to-interannual variability, mainly due to an ENSO teleconnection. In this presentation we will discuss whether near-term climate projections for the area can benefit from initialized decadal hindcasts. In particular, we will explore if the hindcasts capture the main features of seasonal-to-interannual variability in SESA, even if we cannot expect to predict the exact timing of this variability years in advance. In particular, we examine the low-frequency modulation of ENSO-teleconnections in the region, and the extent to which these are tied to decadal-scale changes in the oceanic circulation.

  9. Numerical dosimetric reconstruction of a radiological accident in South America in April 2009.

    Science.gov (United States)

    Courageot, E; Huet, C; Clairand, I; Bottollier-Depois, J F; Gourmelon, P

    2011-03-01

    A severe irradiation accident involving a victim occurred in April 2009 in South America. The victim has found a (192)Ir source fallen from a gammagraphy device and has put it in the left pocket of his pants. Very quickly, an erythema and a blister appeared on the left leg of the victim involving hospitalisation. Following the request of the IAEA assistance, the Ionizing Radiation Dosimetry Laboratory of IRSN was asked to perform a numerical dosimetric reconstruction. A personalised voxel phantom of the victim has been constructed thanks to the Simulation of External Source Accident with Medical images tool developed by the laboratory, and a calculation of the dose with the MCNPX computer code allowed to determine the boundary of the necrotic dose at 25 Gy. On the basis of these calculations, the physicians have performed exeresis of the necrotic region on the left leg on 4 May 2009. Associated with mesenchymal stem cell injection, the leg of the victim was healthy on December 2009.

  10. First Record of Raillietina celebensis (Cestoda: Cyclophyllidea) in South America: Redescription and Phylogeny.

    Science.gov (United States)

    de Oliveira Simões, Raquel; Simões, Susana Balmant Enrique; Luque, José Luis; Iñiguez, Alena Mayo; Júnior, Arnaldo Maldonado

    2017-08-01

    Raillietina celebensis is a cestode that parasitizes the small intestine of rats and humans. Here, we detail the morphology and morphometry of R. celebensis based on specimens collected from Rattus norvegicus in the municipality of São Gonçalo, state of Rio de Janeiro, Brazil, by light and confocal scanning laser microscopies and also report the results of molecular phylogenetic analyses to determine its relationships within the family Davaineidae. Analysis of the number and size of testes, number and shape of rostellar hooks, cirrus sac length, capsules and eggs per capsule, and morphology of the mature proglottid allowed concluding that the present specimens constitute a new record of R. celebensis in South America. Our genetic and phylogenetic analyses, based on the partial small subunit 18S rRNA gene, revealed R. celebensis to be in the family Davaineidae within the genus Raillietina, in agreement with the morphological taxonomy. Phylogenetic trees obtained by neighbor-joining and maximum likelihood methods demonstrated R. celebensis as a unique taxonomic unit, and also demonstrated some taxonomic inconsistences. The incorporation of Brazilian R. celebensis sequences derived from mammals in the phylogeny of davaineids is consistent with the assertion that neither Raillietina nor Fuhrmannetta can be supported as distinct genera.

  11. Phenotypic and genotypic characterization of enterotoxigenic Escherichia coli clinical isolates from northern Colombia, South America.

    Science.gov (United States)

    Guerra, Julio A; Romero-Herazo, Yesenia C; Arzuza, Octavio; Gómez-Duarte, Oscar G

    2014-01-01

    Enterotoxigenic Escherichia coli (ETEC) are major causes of childhood diarrhea in low and middle income countries including Colombia, South America. To understand the diversity of ETEC strains in the region, clinical isolates obtained from northern Colombia children were evaluated for multiple locus sequencing typing, serotyping, classical and nonclassical virulence genes, and antibiotic susceptibility. Among 40 ETEC clinical isolates evaluated, 21 (52.5%) were positive for LT gene, 13 (32.5%) for ST gene, and 6 (15%) for both ST and LT. The most prevalent colonization surface antigens (CS) were CS21 and CFA/I identified in 21 (50%) and 13 (32.5%) isolates, respectively. The eatA, irp2, and fyuA were the most common nonclassical virulence genes present in more than 60% of the isolates. Ampicillin resistance (80% of the strains) was the most frequent phenotype among ETEC strains followed by trimethoprim-sulfamethoxazole resistance (52.5%). Based on multiple locus sequencing typing (MLST), we recognize that 6 clonal groups of ETEC clinical isolates circulate in Colombia. ETEC clinical isolates from children in northern Colombia are highly diverse, yet some isolates circulating in the community belong to well-defined clonal groups that share a unique set of virulence factors, serotypes, and MLST sequence types.

  12. Solar ultraviolet radiation: properties, characteristics and amounts observed in Brazil and South America.

    Science.gov (United States)

    Corrêa, Marcelo de Paula

    2015-01-01

    The beneficial and harmful effects of human exposure to solar ultraviolet radiation (UV-R) are topics that arouse great interest not only among physicians and scientists, but also the general public and the media. Currently, discussions on vitamin D synthesis (beneficial effect) are confronted with the high and growing number of new cases of non-melanoma skin cancer and other diseases of the skin and eyes (harmful effect) diagnosed each year in Brazil. However, the lack of scientific knowledge on the UV-R in Brazil and South America leads to adoption of protective measures based on studies conducted in Europe and USA, where the amounts of UV-R available at surface and the sun-exposure habits and characteristics of the population are significantly different from those observed in Brazil. In order to circumvent this problem, the Brazilian Society of Dermatology recently published the Brazilian Consensus of Photoprotection based on recent studies performed locally. The main goal of this article is to provide detailed educational information on the main properties and characteristics of UV-R and UV index in a simple language. It also provides: a) a summary of UV-R measurements recently performed in Brazil; b) a comparison with those performed in Europe; and, c) an evaluation to further clarify the assessment of potential harm and health effects owing to chronic exposures.

  13. Sustainable management of the Gran Chaco of South America: Ecological promise and economic constraints

    Energy Technology Data Exchange (ETDEWEB)

    Bucher, E.H.; Huszar, P.C.

    1999-10-01

    The vast plain known as the Gran Chaco is a natural region of more than 1--3 million square kilometers, the second largest natural biome in south America, with only the Amazon region being larger. It extends over parts of Argentina, Bolivia, Paraguay and, marginally, Brazil. The original landscape of the region was mostly a park land with patches of hardwoods intermingled with grasslands. Increasing human encroachment, largely by poor campesinos, with associated overgrazing, excessive timber harvesting, charcoal production and over-exploitation of wildlife, is transforming the region into a dense and unproductive shrub land and is contributing to increasing rural poverty. A management system for the sustainable use of the Chaco has been developed based on a multiple-species ranching system that includes beef, timber, charcoal and wildlife production. An evaluation of the management system finds that it is capable of protecting and enhancing the resource base, while providing higher economic returns in a sustainable manner. However, high initial costs, as well as a divergence between the best interests of campersinos and society, jeopardize the feasibility of the managed system.

  14. Participatory Risk Mapping of Malaria Vector Exposure in Northern South America using Environmental and Population Data.

    Science.gov (United States)

    Fuller, D O; Troyo, A; Alimi, T O; Beier, J C

    2014-03-01

    Malaria elimination remains a major public health challenge in many tropical regions, including large areas of northern South America. In this study, we present a new high spatial resolution (90 × 90 m) risk map for Colombia and surrounding areas based on environmental and human population data. The map was created through a participatory multi-criteria decision analysis in which expert opinion was solicited to determine key environmental and population risk factors, different fuzzy functions to standardize risk factor inputs, and variable factor weights to combine risk factors in a geographic information system. The new risk map was compared to a map of malaria cases in which cases were aggregated to the municipio (municipality) level. The relationship between mean municipio risk scores and total cases by muncípio showed a weak correlation. However, the relationship between pixel-level risk scores and vector occurrence points for two dominant vector species, Anopheles albimanus and An. darlingi, was significantly different (p < 0.05) from a random point distribution, as was a pooled point distribution for these two vector species and An. nuneztovari. Thus, we conclude that the new risk map derived based on expert opinion provides an accurate spatial representation of risk of potential vector exposure rather than malaria transmission as shown by the pattern of malaria cases, and therefore it may be used to inform public health authorities as to where vector control measures should be prioritized to limit human-vector contact in future malaria outbreaks.

  15. Magnitude and frequency of heat and cold waves in recent decades: the case of South America

    Directory of Open Access Journals (Sweden)

    G. Ceccherini

    2015-12-01

    Full Text Available In recent decades there has been an increase in magnitude and occurrence of heat waves and a decrease of cold waves which are possibly related to the anthropogenic influence (Solomon et al., 2007. This study describes the extreme temperature regime of heat waves and cold waves across South America over recent years (1980–2014. Temperature records come from the Global Surface Summary of the Day (GSOD, a climatological dataset produced by the National Climatic Data Center that provides records of daily maximum and minimum temperatures acquired worldwide. The magnitude of heat waves and cold waves for each GSOD station are quantified on annual basis by means of the Heat Wave Magnitude Index (Russo et al., 2014 and the Cold Wave Magnitude Index (CWMI, Forzieri et al., 2015. Results indicate an increase in intensity and in frequency of heat waves, with up to 75 % more events occurring only in the last 10 years. Conversely, no significant changes are detected for cold waves. In addition, the trend of the annual temperature range (i.e., yearly mean of Tmax – yearly mean of Tmin is positive – up to 1 °C decade−1 – over the extra-tropics and negative – up to 0.5 °C decade−1 – over the tropic. This dichotomous behaviour indicates that the annual mean of Tmax is generally increasing more than the annual mean of Tmin in the extra-tropics and vice versa in the tropics.

  16. Mitochondrial DNA phylogeography of Caiman crocodilus in Mesoamerica and South America.

    Science.gov (United States)

    Venegas-Anaya, Miryam; Crawford, Andrew J; Escobedo Galván, Armando H; Sanjur, Oris I; Densmore, Llewellyn D; Bermingham, Eldredge

    2008-12-01

    The Neotropical crocodylian species, Caiman crocodilus, is widely distributed through Mesoamerica, northern South America, and the Amazon basin. Four subspecies are recognized within C. crocodilus, suggesting some geographic variation in morphology. In this study, we utilized mitochondrial DNA (mtDNA) sequence data from 45 individuals of C. crocodilus throughout its range to infer its evolutionary history and population structure, as well as to evaluate genealogical support for subspecies and their geographic distributions. Our molecular phylogenetic results identified five mtDNA haplotype clades with a mean sequence divergence of 3.4%, indicating considerable evolutionary independence among phylogeographic lineages. Our results were also broadly consistent with current subspecific taxonomy, with some important additional findings. First, we found substantial genetic structuring within C. c. fuscus from southern Mesoamerica. Second, though we confirmed the existence of a widespread Amazonian clade, we also discovered a cryptic and divergent mtDNA lineage that was indistinguishable from C. c. crocodilus based on external morphology. Third, we confirm the status of C. c. chiapasius as a distinct evolutionary lineage, and provide evidence that C. c. fuscus may be moving northward and hybridizing with C. c. chiapasius in northern Mesoamerica. Finally, our results parallel previous phylogeographic studies of other organisms that have demonstrated significant genetic structure over shorter geographic distances in Mesoamerica compared with Amazonia. We support conservation efforts for all five independent lineages within C. crocodilus, and highlight the subspecies C. c. chiapasius as a unit of particular conservation concern. (c) 2008 Wiley-Liss, Inc.

  17. The 2010-2012 Anomalous Wet Season in Northern South America

    Science.gov (United States)

    Martinez-Agudelo, J. A.; Arias, P. A.; Vieira, S. C.

    2014-12-01

    During 2010-2012, northern South America experienced one of the strongest wet seasons during the recent decades, with socio-economic implications of wide proportions. This period was characterized by two stronger-than-average La Niña events, occurred in 2010-2011 and 2011-2012. This study focuses on identifying the main moisture sources for the anomalous wet season occurred in this region during this period and their association with the La Niña events observed in the equatorial Pacific. Our results suggest that the main moisture sources to this anomalous wet season were the Pacific Ocean (via the westerly flow of the Choco jet) and the Caribbean Sea (via the weakening of the Caribbean low-level jet). These changes appear to be associated not only to El Niño-Southern Oscillation (ENSO)-driven sea surface temperature anomalies in the eastern Pacific, Caribbean Sea, and north Atlantic, but also to ENSO-independent variability in the Atlantic Ocean.

  18. The coexistence of peace and conflict in South America: toward a new conceptualization of types of peace

    OpenAIRE

    Jorge Mario Battaglino

    2012-01-01

    South America's predominant democratic regimes and its increasing interdependence on regional trade have not precluded the emergence of militarized crises between Colombia and Venezuela or the revival of boundary claims between Chile and Peru. This way, how can we characterize a zone that, in spite of its flourishing democracy and dense economic ties, remain involved in territorial disputes for whose resolution the use of force has not yet been discarded? This article contends that existing c...

  19. Epidemiology of lobomycosis-like disease in bottlenose dolphins Tursiops spp. from South America and southern Africa