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Sample records for andes virus chi-7913

  1. Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters

    Science.gov (United States)

    2007-05-01

    Microbiology . All Rights Reserved. Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters Victoria Wahl-Jensen,1 Jennifer...Ye, C., J. Prescott , R. Nofchissey, D. Goade, and B. Hjelle. 2004. Neutralizing antibodies and Sin Nombre virus RNA after recovery from hantavirus

  2. The major cellular sterol regulatory pathway is required for Andes virus infection.

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    Josiah Petersen

    2014-02-01

    Full Text Available The Bunyaviridae comprise a large family of RNA viruses with worldwide distribution and includes the pathogenic New World hantavirus, Andes virus (ANDV. Host factors needed for hantavirus entry remain largely enigmatic and therapeutics are unavailable. To identify cellular requirements for ANDV infection, we performed two parallel genetic screens. Analysis of a large library of insertionally mutagenized human haploid cells and a siRNA genomic screen converged on components (SREBP-2, SCAP, S1P and S2P of the sterol regulatory pathway as critically important for infection by ANDV. The significance of this pathway was confirmed using functionally deficient cells, TALEN-mediated gene disruption, RNA interference and pharmacologic inhibition. Disruption of sterol regulatory complex function impaired ANDV internalization without affecting virus binding. Pharmacologic manipulation of cholesterol levels demonstrated that ANDV entry is sensitive to changes in cellular cholesterol and raises the possibility that clinically approved regulators of sterol synthesis may prove useful for combating ANDV infection.

  3. Long-Term Single-Dose Efficacy of a Vesicular Stomatitis Virus-Based Andes Virus Vaccine in Syrian Hamsters

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    Joseph Prescott

    2014-01-01

    Full Text Available Andes virus (ANDV is highly pathogenic in humans and is the primary etiologic agent of hantavirus cardiopulmonary syndrome (HCPS in South America. Case-fatality rates are as high as 50% and there are no approved vaccines or specific therapies for infection. Our laboratory has recently developed a replication-competent recombinant vesicular stomatitis virus (VSV-based vaccine that expressed the glycoproteins of Andes virus in place of the native VSV glycoprotein (G. This vaccine is highly efficacious in the Syrian hamster model of HCPS when given 28 days before challenge with ANDV, or when given around the time of challenge (peri-exposure, and even protects when administered post-exposure. Herein, we sought to test the durability of the immune response to a single dose of this vaccine in Syrian hamsters. This vaccine was efficacious in hamsters challenged intranasally with ANDV 6 months after vaccination (p = 0.025, but animals were not significantly protected following 1 year of vaccination (p = 0.090. The decrease in protection correlated with a reduction of measurable neutralizing antibody responses, and suggests that a more robust vaccination schedule might be required to provide long-term immunity.

  4. Novel Strain of Andes Virus Associated with Fatal Human Infection, Central Bolivia

    Science.gov (United States)

    Cruz, Cristhopher D.; Vallejo, Efrain; Agudo, Roberto; Vargas, Jorge; Blazes, David L.; Guevara, Carolina; Laguna-Torres, V. Alberto; Halsey, Eric S.; Kochel, Tadeusz J.

    2012-01-01

    To better describe the genetic diversity of hantaviruses associated with human illness in South America, we screened blood samples from febrile patients in Chapare Province in central Bolivia during 2008–2009 for recent hantavirus infection. Hantavirus RNA was detected in 3 patients, including 1 who died. Partial RNA sequences of small and medium segments from the 3 patients were most closely related to Andes virus lineages but distinct (1 hantaviruses; the highest prevalence was among agricultural workers. Because of the high level of human exposure to hantavirus strains and the severity of resulting disease, additional studies are warranted to determine the reservoirs, ecologic range, and public health effect of this novel strain of hantavirus. PMID:22515983

  5. Pathogenesis and host response in Syrian hamsters following intranasal infection with Andes virus.

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    David Safronetz

    2011-12-01

    Full Text Available Hantavirus pulmonary syndrome (HPS, also referred to as hantavirus cardiopulmonary syndrome (HCPS, is a rare but frequently fatal disease caused by New World hantaviruses. In humans HPS is associated with severe pulmonary edema and cardiogenic shock; however, the pathogenesis of this disease remains unclear largely due to a lack of suitable animal models for the study of disease progression. In this study we monitored clinical, virological, pathophysiological parameters and host immunological responses to decipher pathological factors and events in the lethal Syrian hamster model of HPS following intranasal inoculation of Andes virus. Transcriptional profiling of the host gene responses demonstrated a suppression of innate immune responses in most organs analyzed during the early stage of infection, except for in the lung which had low level activation of several pro-inflammatory genes. During this phase Andes virus established a systemic infection in hamsters, with viral antigen readily detectable in the endothelium of the majority of tissues analyzed by 7-8 days post-inoculation. Despite wide-spread infection, histological analysis confirmed pathological abnormalities were almost exclusively found in the lungs. Immediately preceding clinical signs of disease, intense activation of pro-inflammatory and Th1/Th2 responses were observed in the lungs as well as the heart, but not in peripheral organs, suggesting that localized immune-modulations by infection is paramount to pathogenesis. Throughout the course of infection a strong suppression of regulatory T-cell responses was noted and is hypothesized to be the basis of the aberrant immune activations. The unique and comprehensive monitoring of host immune responses to hantavirus infection increases our understanding of the immuno-pathogenesis of HPS and will facilitate the development of treatment strategies targeting deleterious host immunological responses.

  6. In vitro and in vivo activity of ribavirin against Andes virus infection.

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    David Safronetz

    Full Text Available Pathogenic hantaviruses are a closely related group of rodent-borne viruses which are responsible for two distinct diseases in humans, hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome (HPS, otherwise known as hantavirus cardiopulmonary syndrome, HCPS. The antiviral effect of ribavirin against Old World hantaviruses, most notably Hantaan virus, is well documented; however, only a few studies have addressed its inhibitory effect on New World hantaviruses. In the present study, we demonstrate that ribavirin is highly active against Andes virus (ANDV, an important etiological agent of HPS, both in vitro and in vivo using a lethal hamster model of HPS. Treatment of ANDV infected Vero E6 cells with ribavirin resulted in dose-dependent reductions in viral RNA and protein as well as virus yields with a half maximal inhibitory concentration between 5 and 12.5 µg ml(-1. In hamsters, treatment with as little as 5 mg kg(-1 day(-1 was 100% effective at preventing lethal HPS disease when therapy was administered by intraperitoneal injection from day 1 through day 10 post-infection. Significant reductions were observed in ANDV RNA and antigen positive cells in lung and liver tissues. Ribavirin remained completely protective when administered by intraperitoneal injections up to three days post-infection. In addition, we show that daily oral ribavirin therapy initiated 1 day post-infection and continuing for ten days is also protective against lethal ANDV disease, even at doses of 5 mg kg(-1 day(-1. Our results suggest ribavirin treatment is beneficial for postexposure prophylaxis against HPS-causing hantaviruses and should be considered in scenarios where exposure to the virus is probable. The similarities between the results obtained in this study and those from previous clinical evaluations of ribavirin against HPS, further validate the hamster model of lethal HPS and demonstrate its usefulness in screening antiviral agents against

  7. Ecology, Genetic Diversity, and Phylogeographic Structure of Andes Virus in Humans and Rodents in Chile▿

    Science.gov (United States)

    Medina, Rafael A.; Torres-Perez, Fernando; Galeno, Hector; Navarrete, Maritza; Vial, Pablo A.; Palma, R. Eduardo; Ferres, Marcela; Cook, Joseph A.; Hjelle, Brian

    2009-01-01

    Andes virus (ANDV) is the predominant etiologic agent of hantavirus cardiopulmonary syndrome (HCPS) in southern South America. In Chile, serologically confirmed human hantavirus infections have occurred throughout a wide latitudinal distribution extending from the regions of Valparaíso (32 to 33°S) to Aysén (46°S) in southern Patagonia. In this study, we found seropositive rodents further north in the Coquimbo region (30°S) in Chile. Rodent seroprevalence was 1.4%, with Oligoryzomys longicaudatus displaying the highest seroprevalence (5.9%), followed by Abrothrix longipilis (1.9%) and other species exhibiting ≤0.6% seropositivity. We sequenced partial ANDV small (S) segment RNA from 6 HCPS patients and 32 rodents of four different species collected throughout the known range of hantavirus infection in Chile. Phylogenetic analyses showed two major ANDV South (ANDV Sout) clades, congruent with two major Chilean ecoregions, Mediterranean (Chilean matorral [shrubland]) and Valdivian temperate forest. Human and rodent samples grouped according to geographic location. Phylogenetic comparative analyses of portions of S and medium segments (encoding glycoproteins Gn and Gc) from a subset of rodent specimens exhibited similar topologies, corroborating two major ANDV Sout clades in Chile and suggesting that yet unknown factors influence viral gene flow and persistence throughout the two Chilean ecoregions. Genetic algorithms for recombination detection identified recombination events within the S segment. Molecular demographic analyses showed that the virus is undergoing purifying selection and demonstrated a recent exponential growth in the effective number of ANDV Sout infections in Chile that correlates with the increased number of human cases reported. Although we determined virus sequences from four rodent species, our results confirmed O. longicaudatus as the primary ANDV Sout reservoir in Chile. While evidence of geographic differentiation exists, a single

  8. Ecology, genetic diversity, and phylogeographic structure of andes virus in humans and rodents in Chile.

    Science.gov (United States)

    Medina, Rafael A; Torres-Perez, Fernando; Galeno, Hector; Navarrete, Maritza; Vial, Pablo A; Palma, R Eduardo; Ferres, Marcela; Cook, Joseph A; Hjelle, Brian

    2009-03-01

    Andes virus (ANDV) is the predominant etiologic agent of hantavirus cardiopulmonary syndrome (HCPS) in southern South America. In Chile, serologically confirmed human hantavirus infections have occurred throughout a wide latitudinal distribution extending from the regions of Valparaíso (32 to 33 degrees S) to Aysén (46 degrees S) in southern Patagonia. In this study, we found seropositive rodents further north in the Coquimbo region (30 degrees S) in Chile. Rodent seroprevalence was 1.4%, with Oligoryzomys longicaudatus displaying the highest seroprevalence (5.9%), followed by Abrothrix longipilis (1.9%) and other species exhibiting Chile. Phylogenetic analyses showed two major ANDV South (ANDV Sout) clades, congruent with two major Chilean ecoregions, Mediterranean (Chilean matorral [shrubland]) and Valdivian temperate forest. Human and rodent samples grouped according to geographic location. Phylogenetic comparative analyses of portions of S and medium segments (encoding glycoproteins Gn and Gc) from a subset of rodent specimens exhibited similar topologies, corroborating two major ANDV Sout clades in Chile and suggesting that yet unknown factors influence viral gene flow and persistence throughout the two Chilean ecoregions. Genetic algorithms for recombination detection identified recombination events within the S segment. Molecular demographic analyses showed that the virus is undergoing purifying selection and demonstrated a recent exponential growth in the effective number of ANDV Sout infections in Chile that correlates with the increased number of human cases reported. Although we determined virus sequences from four rodent species, our results confirmed O. longicaudatus as the primary ANDV Sout reservoir in Chile. While evidence of geographic differentiation exists, a single cosmopolitan lineage of ANDV Sout remains the sole etiologic agent for HCPS in Chile.

  9. Endocytic Pathways Used by Andes Virus to Enter Primary Human Lung Endothelial Cells.

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    Cheng-Feng Chiang

    Full Text Available Andes virus (ANDV is the major cause of hantavirus pulmonary syndrome (HPS in South America. Despite a high fatality rate (up to 40%, no vaccines or antiviral therapies are approved to treat ANDV infection. To understand the role of endocytic pathways in ANDV infection, we used 3 complementary approaches to identify cellular factors required for ANDV entry into human lung microvascular endothelial cells. We screened an siRNA library targeting 140 genes involved in membrane trafficking, and identified 55 genes required for ANDV infection. These genes control the major endocytic pathways, endosomal transport, cell signaling, and cytoskeleton rearrangement. We then used infectious ANDV and retroviral pseudovirions to further characterize the possible involvement of 9 of these genes in the early steps of ANDV entry. In addition, we used markers of cellular endocytosis along with chemical inhibitors of known endocytic pathways to show that ANDV uses multiple routes of entry to infect target cells. These entry mechanisms are mainly clathrin-, dynamin-, and cholesterol-dependent, but can also occur via a clathrin-independent manner.

  10. Human T-lymphotropic virus type 1 infection is frequent in rural communities of the southern Andes of Peru.

    Science.gov (United States)

    Ita, Fanny; Mayer, Erick F; Verdonck, Kristien; Gonzalez, Elsa; Clark, Daniel; Gotuzzo, Eduardo

    2014-02-01

    To evaluate the presence of human T-lymphotropic virus type 1 (HTLV-1) infection in isolated rural communities in the southern Andes of Peru. We conducted a cross-sectional study in five communities located in three provinces in Ayacucho, Peru. The five communities are located at >3000 meters above sea level and are mainly rural, and more than 85% of the population speaks Quechua. Volunteers aged 12 years and older were included. Clinical and epidemiological data were collected, along with a blood sample for serological testing. We included 397 participants; their median age was 41 years (interquartile range 31-57 years) and 69% were women. According to our definitions, 98% were of Quechua origin. HTLV-1 was diagnosed in 11 people: 0/164 in Cangallo, 3/154 (2%) in Vilcashuaman, and 8/79 (10%) in Parinacochas. There were no cases of HTLV-2. All the HTLV-1-positive participants were born in Ayacucho and were of Quechua origin; they ranged in age from 29 to 87 years (median 56 years) and 10/11 were women. Ten were apparently healthy, and one woman was diagnosed with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Three out of 11 had a family member with a lower limb impairment compatible with HAM/TSP. The fact that HTLV-1 infection was present in two out of three provinces suggests that HTLV-1 could be highly endemic in the southern Andes in the Quechua population. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Experimental Andes virus infection in deer mice: characteristics of infection and clearance in a heterologous rodent host.

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    Jessica R Spengler

    Full Text Available New World hantaviruses can cause hantavirus cardiopulmonary syndrome with high mortality in humans. Distinct virus species are hosted by specific rodent reservoirs, which also serve as the vectors. Although regional spillover has been documented, it is unknown whether rodent reservoirs are competent for infection by hantaviruses that are geographically separated, and known to have related, but distinct rodent reservoir hosts. We show that Andes virus (ANDV of South America, carried by the long tailed pygmy rice rat (Oligoryzomys longicaudatus, infects and replicates in vitro and in vivo in the deer mouse (Peromyscus maniculatus, the reservoir host of Sin Nombre virus (SNV, found in North America. In experimentally infected deer mice, viral RNA was detected in the blood, lung, heart and spleen, but virus was cleared by 56 days post inoculation (dpi. All of the inoculated deer mice mounted a humoral immune response by 14 dpi, and produced measurable amounts of neutralizing antibodies by 21 dpi. An up-regulation of Ccl3, Ccl4, Ccl5, and Tgfb, a strong CD4⁺ T-cell response, and down-regulation of Il17, Il21 and Il23 occurred during infection. Infection was transient with an absence of clinical signs or histopathological changes. This is the first evidence that ANDV asymptomatically infects, and is immunogenic in deer mice, a non-natural host species of ANDV. Comparing the immune response in this model to that of the immune response in the natural hosts upon infection with their co-adapted hantaviruses may help clarify the mechanisms governing persistent infection in the natural hosts of hantaviruses.

  12. Andes virus infections in the rodent reservoir and in humans vary across contrasting landscapes in Chile

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    Torres-Pérez, Fernando; Palma, R. Eduardo; Hjelle, Brian; Ferres, Marcela; Cook, Joseph A.

    2009-01-01

    Hantavirus cardiopulmonary syndrome (HCPS) is an emerging infectious disease first reported in Chile in 1995. Andes hantavirus (ANDV) is responsible for the more than 500 cases of HCPS reported in Chile. Previous work showed that ANDV is genetically differentiated in Chile across contrasting landscapes. To determine whether the reservoir rodent (Oligoryzomys longicaudatus) populations are also geographically segregated, we conducted range-wide spatial genetic analyses of O. longicaudatus in Chile using the mitochondrial DNA cytochrome b gene. Given that landscape structure influences the incidence of hantavirus infections, we also tested 772 O. longicaudatus specimens for antibodies to ANDV captured during the period 2000 − 2006. Population genetic analyses of O. longicaudatus are largely congruent with those reported for ANDV, with the host primarily differentiated according to three defined ecoregions, Mediterranean, Valdivian rain forest and North Patagonian rain forest. Significant differences in the relative prevalence of anti-ANDV antibodies in rodent samples also were found across the three ecoregions. We relate these results to the number of reported human HCPS cases in Chile, and discuss the importance of landscape differences in light of ANDV transmission to humans and among rodent populations. PMID:19632357

  13. Transcriptome markers of viral persistence in naturally-infected andes virus (bunyaviridae seropositive long-tailed pygmy rice rats.

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    Corey L Campbell

    Full Text Available Long-tailed pygmy rice rats (Oligoryzomys longicaudatus are principal reservoir hosts of Andes virus (ANDV (Bunyaviridae, which causes most hantavirus cardiopulmonary syndrome cases in the Americas. To develop tools for the study of the ANDV-host interactions, we used RNA-Seq to generate a de novo transcriptome assembly. Splenic RNA from five rice rats captured in Chile, three of which were ANDV-infected, was used to generate an assembly of 66,173 annotated transcripts, including noncoding RNAs. Phylogenetic analysis of selected predicted proteins showed similarities to those of the North American deer mouse (Peromyscus maniculatus, the principal reservoir of Sin Nombre virus (SNV. One of the infected rice rats had about 50-fold more viral burden than the others, suggesting acute infection, whereas the remaining two had levels consistent with persistence. Differential expression analysis revealed distinct signatures among the infected rodents. The differences could be due to 1 variations in viral load, 2 dimorphic or reproductive differences in splenic homing of immune cells, or 3 factors of unknown etiology. In the two persistently infected rice rats, suppression of the JAK-STAT pathway at Stat5b and Ccnot1, elevation of Casp1, RIG-I pathway factors Ppp1cc and Mff, and increased FC receptor-like transcripts occurred. Caspase-1 and Stat5b activation pathways have been shown to stimulate T helper follicular cell (TFH development in other species. These data are also consistent with reports suggestive of TFH stimulation in deer mice experimentally infected with hantaviruses. In the remaining acutely infected rice rat, the apoptotic pathway marker Cox6a1 was elevated, and putative anti-viral factors Abcb1a, Fam46c, Spp1, Rxra, Rxrb, Trmp2 and Trim58 were modulated. Transcripts for preproenkephalin (Prenk were reduced, which may be predictive of an increased T cell activation threshold. Taken together, this transcriptome dataset will permit rigorous

  14. Atomic Structure and Biochemical Characterization of an RNA Endonuclease in the N Terminus of Andes Virus L Protein.

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    Yaiza Fernández-García

    2016-06-01

    Full Text Available Andes virus (ANDV is a human-pathogenic hantavirus. Hantaviruses presumably initiate their mRNA synthesis by using cap structures derived from host cell mRNAs, a mechanism called cap-snatching. A signature for a cap-snatching endonuclease is present in the N terminus of hantavirus L proteins. In this study, we aimed to solve the atomic structure of the ANDV endonuclease and characterize its biochemical features. However, the wild-type protein was refractory to expression in Escherichia coli, presumably due to toxic enzyme activity. To circumvent this problem, we introduced attenuating mutations in the domain that were previously shown to enhance L protein expression in mammalian cells. Using this approach, 13 mutant proteins encompassing ANDV L protein residues 1-200 were successfully expressed and purified. Protein stability and nuclease activity of the mutants was analyzed and the crystal structure of one mutant was solved to a resolution of 2.4 Å. Shape in solution was determined by small angle X-ray scattering. The ANDV endonuclease showed structural similarities to related enzymes of orthobunya-, arena-, and orthomyxoviruses, but also differences such as elongated shape and positively charged patches surrounding the active site. The enzyme was dependent on manganese, which is bound to the active site, most efficiently cleaved single-stranded RNA substrates, did not cleave DNA, and could be inhibited by known endonuclease inhibitors. The atomic structure in conjunction with stability and activity data for the 13 mutant enzymes facilitated inference of structure-function relationships in the protein. In conclusion, we solved the structure of a hantavirus cap-snatching endonuclease, elucidated its catalytic properties, and present a highly active mutant form, which allows for inhibitor screening.

  15. Serum levels of interleukin-6 are linked to the severity of the disease caused by Andes Virus.

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    Jenniffer Angulo

    2017-07-01

    Full Text Available Andes virus (ANDV is the etiological agent of hantavirus cardiopulmonary syndrome in Chile. In this study, we evaluated the profile of the pro-inflammatory cytokines IL-1β, IL-12p70, IL-21, TNF-α, IFN-γ, IL-10 and IL-6 in serum samples of ANDV-infected patients at the time of hospitalization. The mean levels of circulating cytokines were determined by a Bead-Based Multiplex assay coupled with Luminex detection technology, in order to compare 43 serum samples of healthy controls and 43 samples of ANDV-infected patients that had been categorized according to the severity of disease. When compared to the controls, no significant differences in IL-1β concentration were observed in ANDV-infected patients (p = 0.9672, whereas levels of IL-12p70 and IL-21 were significantly lower in infected cases (p = <0.0001. Significantly elevated levels of TNF-α, IFN-γ, IL-10, and IL-6 were detected in ANDV-infected individuals (p = <0.0001, 0.0036, <0.0001, <0.0001, respectively. Notably, IL-6 levels were significantly higher (40-fold in the 22 patients with severe symptoms compared to the 21 individuals with mild symptoms (p = <0.0001. Using multivariate regression models, we show that IL-6 levels has a crude OR of 14.4 (CI: 3.3-63.1. In conclusion, the serum level of IL-6 is a significant predictor of the severity of the clinical outcome of ANDV-induced disease.

  16. ASTER Andes

    Science.gov (United States)

    2000-01-01

    In this image of the Andes along the Chile-Bolivia border, the visible and infrared data have been computer enhanced to exaggerate the color differences of the different materials. The scene is dominated by the Pampa Luxsar lava complex, occupying the upper right two-thirds of the scene. Lava flows are distributed around remnants of large dissected cones, the largest of which is Cerro Luxsar. On the middle left edge of the image are the Olca and Parumastrato volcanoes, which appear in blue due to a lack of vegetation (colored red in this composite). This image covers an area 60 kilometers (37 miles) wide and 60 kilometers (37 miles) long in three bands of the reflected visible and infrared wavelength region. It was acquired on April 7, 2000.The image is located at 21 degrees south latitude, 68.3 degrees west longitude. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats

  17. Andes 1997 Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Central Andes gravity data (6,151 records) were compiled by Professor Gotze and the MIGRA Group. This data base was received in April, 1997. Principal gravity...

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

    Science.gov (United States)

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

    2014-02-01

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

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

    OpenAIRE

    Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M.; Salmon-Mulanovich, Gabriela; Guezala, M. Claudia; Albujar, Christian; Mendoza, A. Patricia; Tinoco, Yeny O.; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah

    2014-01-01

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

  20. Andes: An intelligent homework helper

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    van de Sande, Brett; Vanlehn, Kurt; Treacy, Don; Shelby, Bob; Wintersgill, Mary

    2007-03-01

    Andes (www.andes.pitt.edu) is an intelligent tutor homework system designed for use as the homework portion of an introductory physics course. It encourages students to use good problem solving techniques and provides immediate feedback on each step of a problem solution along with hints on request. I will discuss how Andes works, from a student perspective, and present research demonstrating its effectiveness as a pedagogical tool. Then, I will discuss using Andes as a tool for conducting education research, briefly reviewing several studies conducted using Andes. Finally, I will show how logs of student solutions to Andes problems can be used to develop cognitive models of student learning.

  1. Charles Darwin in the Andes

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    Bizzo, Nelio; Bizzo, Luis Eduardo Maestrelli

    2006-01-01

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

  2. Volcanic deformation in the Andes

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    Riddick, S.; Fournier, T.; Pritchard, M.

    2009-05-01

    We present the results from an InSAR survey of volcanic activity in South America. We use data from the Japanese Space Agency's ALOS L-band radar satellite from 2006-2009. The L-band instrument provides better coherence in densely vegetated regions, compared to the shorter wave length C-band data. The survey reveals volcano related deformation in regions, north, central and southern, of the Andes volcanic arc. Since observations are limited to the austral summer, comprehensive coverage of all volcanoes is not possible. Yet, our combined observations reveal volcanic/hydrothermal deformation at Lonquimay, Llaima, Laguna del Maule, and Chaitén volcanoes, extend deformation measurements at Copahue, and illustrate temporal complexity to the previously described deformation at Cerro Hudson and Cordón Caulle. No precursory deformation is apparent before the large Chaitén eruption (VEI_5) of 2 May 2008, (at least before 16 April) suggesting rapid magma movement from depth at this long dormant volcano. Subsidence at Ticsani Volcano occurred coincident with an earthquake swarm in the same region.

  3. ANDES: An Underground Laboratory in South America

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    Dib, Claudio O.

    ANDES (Agua Negra Deep Experiment Site) is an underground laboratory, proposed to be built inside the Agua Negra road tunnel that will connect Chile (IV Region) with Argentina (San Juan Province) under the Andes Mountains. The Laboratory will be 1750 meters under the rock, becoming the 3rd deepest underground laboratory of this kind in the world, and the first in the Southern Hemisphere. ANDES will be an international Laboratory, managed by a Latin American consortium. The laboratory will host experiments in Particle and Astroparticle Physics, such as Neutrino and Dark Matter searches, Seismology, Geology, Geophysics and Biology. It will also be used for the development of low background instrumentation and related services. Here we present the general features of the proposed laboratory, the current status of the proposal and some of its opportunities for science.

  4. Andes: An Intelligent Homework System for Introductory Physics

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    van de Sande, Brett; VanLehn, K.; Hausmann, R.; Treacy, D.; Shelby, R.

    2006-12-01

    We know that students benefit from solving homework problems under the guidance of an expert (human) tutor. The Andes system (http://www.andes.pitt.edu) is designed for students to solve homework problems under the guidance of an expert computer tutor. Andes encourages students to use sound problem solving techniques and provides immediate right/wrong feedback on each step of a solution. On request, Andes also provides hints based on previous student actions. I will discuss how Andes works, from a student's perspective, and summarize research that demonstrates its effectiveness as a pedagogical tool. I will also discuss how Andes can function as a tool for conducting educational research, presenting an investigation of students' hint usage as an example.

  5. Changing Student Attitudes using Andes, An Intelligent Homework System

    Science.gov (United States)

    van de Sande, Brett; Vanlehn, Kurt; Treacy, Don; Shelby, Bob; Wintersgill, Mary

    2007-03-01

    The size of introductory physics lectures often inhibits personal homework assistance and timely corrective feedback. Andes, an intelligent homework help system designed for two semesters of introductory physics, can fill this need by encouraging students to use sound problem solving techniques and providing immediate feedback on each step of a solution. On request, Andes provides principles-based hints based on previous student actions. A multi-year study at the U.S. Naval Academy demonstrates that students using Andes perform better than students working the same problems as graded pencil and paper homeworks. In addition, student attitude surveys show that Andes is preferred over other homework systems. These findings have implications for student attitudes toward, and mastery of, physics. See http://www.andes.pitt.edu for more information.

  6. The Glaciation of the Ecuadorian Andes

    Science.gov (United States)

    Schubert, Carlos

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

  7. Mountain building in the central Andes

    Science.gov (United States)

    Kono, Masaru; Fukao, Yoshio; Yamamoto, Akihiko

    1989-04-01

    The Central Andes is the middle part of the Andean chain between about 13°S and 27°S, characterized by the parallel running high mountain chains (the Western and Eastern Cordilleras) at the edges of high plateaus with a height of about 4000 m and a width of 200 to 450 km (the Altiplano-Puna). From the examination of geophysical and geological data in this area, including earthquakes, deformation, gravity anomaly, volcanism, uplift history, and plate motion, we conclude that the continued plate subduction with domination of compressive stress over the entire arc system is the main cause of the tectonic style of the Central Andes. We propose that the present cycle of mountain building has continued in the Cenozoic with the most active phase since the Miocene, and that the present subduction angle (30°) is not typical in that period but that subduction with more shallowly dipping oceanic lithosphere has prevailed at least since the Miocene, because of the young and buoyant slab involved. This situation is responsible for the production of a broad zone of partial melt in the mantle above the descending slab. Addition of volcanic materials was not restricted to the western edge (where active volcanoes of the Western Cordillera exist) but extended to the western and central portion of the Altiplano-Puna. The western half of the Central Andes is essentially isostatic because the heat transferred with the volcanic activities softened the crust there. In the eastern edge, the thermal effect is small, and the crust is strongly pushed by the westward moving South American plate. This caused the shortening of crustal blocks due to reverse faulting and folding in the Eastern Cordillera and Amazonian foreland. The magmatism and crustal accretion are dominant at the western end of the mountain system and decrease eastward, while the compression and consequent crustal shortening are strongest at the eastern end and wane toward west. These two processes are superposed between

  8. Finanzas de la Universidad de Los Andes

    Directory of Open Access Journals (Sweden)

    Rosa Aura Casal de Altuve

    2006-01-01

    Full Text Available El objetivo primario de este artículo es el de fungir de base comparativa para otros estudios de países latinoamericanos que podrían estar considerando síntomas similares en el área de la investigación contable. El punto de partida lo representa un estudio de caso de los profesores del Departamento de Contabilidad y Finanzas de la Facultad de Ciencias Económicas y Sociales de la Universidad de los Andes. El artículo analiza la relación entre investigación y enseñanza y si el departamento está o no cumpliendo con sus objetivos. Un objetivo secundario consiste en la determinación de los posibles factores que han tenido una influencia significativa en el desempeño de la investigación y de la enseñanza por parte de los investigadores. Basándose en entrevistas y recolección directa de datos, se consideran las estrategias institucionales para fijar los objetivos de las actividades de investigación

  9. Diversification of clearwing butterflies with the rise of the Andes.

    Science.gov (United States)

    De-Silva, Donna Lisa; Elias, Marianne; Willmott, Keith; Mallet, James; Day, Julia J

    2016-01-01

    Despite the greatest butterfly diversity on Earth occurring in the Neotropical Andes and Amazonia, there is still keen debate about the origins of this exceptional biota. A densely sampled calibrated phylogeny for a widespread butterfly subtribe, Oleriina (Nymphalidae: Ithomiini) was used to estimate the origin, colonization history and diversification of this species-rich group. Neotropics. Ancestral elevation and biogeographical ranges were reconstructed using data generated from detailed range maps and applying the dispersal-extinction-cladogenesis model using stratified palaeogeographical time slice matrices. The pattern of diversification through time was examined by comparing constant and variable rate models. We also tested the hypothesis that a change in elevation is associated with speciation. The Oleriina likely originated in the Andes in the Early to Middle Miocene and rapidly diversified to include four genera all of which also originated in the Andes. These clades, together with four species groups, experienced varying spatial and temporal patterns of diversification. An overall early burst and decreasing diversification rate is identified, and this pattern is reflected for most subclades. Changes in the palaeogeological landscape, particularly the prolonged uplift of the Andes, had a profound impact on the diversification of the subtribe. The Oleriina mostly remained within the Andes and vicariant speciation resulted in some instances. Dynamic dispersal occurred with the disappearance of geological barriers such as the Acre System and the subtribe exploited newly available habitats. Our results confirm the role of the Andean uplift in the evolution of Neotropical biodiversity.

  10. Glaciation in the Andes during the Lateglacial and Holocene

    Science.gov (United States)

    Rodbell, Donald T.; Smith, Jacqueline A.; Mark, Bryan G.

    2009-10-01

    This review updates the chronology of Andean glaciation during the Lateglacial and the Holocene from the numerous articles and reviews published over the past three decades. The Andes, which include some of the world's wettest and driest mountainous regions, offer an unparalleled opportunity to elucidate spatial and temporal patterns of glaciation along a continuous 68-degree meridional transect. The geographic and altitudinal extent of modern glaciers and the sensitivity of both modern and former glaciers to respond to changes in specific climatic variables reflect broad-scale atmospheric circulation and consequent regional moisture patterns. Glaciers in the tropical Andes and in the mid-latitude Andes are likely to have been far more sensitive to changes in temperature than glaciers in the dry subtropical Andes. Broad-scale temporal and spatial patterns of glaciation during the Lateglacial are apparent. In the southernmost Andes, the Lateglacial chronology appears to have a strong Antarctic signature with the best-dated moraines correlating closely with the Antarctic Cold Reversal. The southernmost Andes do not appear to have experienced a significant ice advance coeval with the Younger Dryas (YD) climatic reversal. At the other end of the Andes, from ˜0 to 9°N, a stronger YD connection may exist, but critical stratigraphic and geochronologic work is required before a YD ice advance can be fully demonstrated. In the central Andes of Peru, well-dated moraines record a significant ice readvance at the onset of the YD, but ice was retreating during much of the remaining YD interval. The spatial-temporal pattern of Holocene glaciation exhibits tantalizing but incomplete evidence for an Early to Mid-Holocene ice advance(s) in many regions, but not in the arid subtropical Andes, where moraines deposited during or slightly prior to the Little Ice Age (LIA) record the most extensive advance of the Holocene. In many regions, there is strong evidence for Neoglacial

  11. A rapid method for infectivity titration of Andes hantavirus using flow cytometry.

    Science.gov (United States)

    Barriga, Gonzalo P; Martínez-Valdebenito, Constanza; Galeno, Héctor; Ferrés, Marcela; Lozach, Pierre-Yves; Tischler, Nicole D

    2013-11-01

    The focus assay is currently the most commonly used technique for hantavirus titer determination. This method requires an incubation time of between 5 and 11 days to allow the appearance of foci after several rounds of viral infection. The following work presents a rapid Andes virus (ANDV) titration assay, based on viral nucleocapsid protein (N) detection in infected cells by flow cytometry. To this end, an anti-N monoclonal antibody was used that was developed and characterized previously. ANDV N could be detected as early as 6 h post-infection, while viral release was not observed until 24-48 h post-infection. Given that ANDV detection was performed during its first round of infection, a time reduction for titer determination was possible and provided results in only two days. The viral titer was calculated from the percentage of N positive cells and agreed with focus assay titers. Furthermore, the assay was applied to quantify the inhibition of ANDV cell entry by patient sera and by preventing endosome acidification. This novel hantavirus titration assay is a highly quantitative and sensitive tool that facilitates infectivity titration of virus stocks, rapid screening for antiviral drugs, and may be further used to detect and quantify infectious virus in human samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Rock Glacier Response to Climate Change in the Argentinian Andes

    Science.gov (United States)

    Drewes, J.; Korup, O.; Moreiras, S.

    2017-12-01

    Rock glaciers are bodies of frozen debris and ice that move under the influence of gravity in permafrost areas. Rock glaciers may store a large amount of sediments and play an important role as prime movers of debris in the Andean sediment cascade. However, little is known about how much sediment and water rock glaciers may store at the mountain-belt scale, and the few existing estimates vary considerably. We address this question for the Argentinian Andes, for which a new glacial inventory containing more than 6500 rock glaciers gives us the opportunity to analyse their relevance within the sediment cascade. We examine the inventory for catchments in five sub-regions, i.e. the Desert Andes (22°-31°S); the Central Andes (31°-36°S); the Northern Andes of Patagonia (36°-45°S); the Southern Andes of Patagonia (45°-52°S); and Tierra del Fuego (52°-55°S), together with climate variables of the WorldClim datasets, and digital topographic data, to estimate how rock-glacier extents may change under different past and future climate scenarios. We observe for the northern Desert Andes that rock glacier toes are at 4000 to 5000 m a.s.l. and a mean annual temperature range of 3° and 8°C, though most rock glaciers are in areas with mean annual temperatures between -5 and 5°C, marking a distinct thermal niche. Rock glaciers are traditionally viewed as diagnostic of sporadic alpine permafrost and their toes are often near the annual mean 0°C isotherm. However, we find that only rock glaciers in the southern Desert Andes and Central Andes are located where annual mean temperature is -2°C. Future scenarios project an increase of > four degrees in these areas, which may further degrade ground ice and potentially change the rates at which rock glaciers advance. Where active rock glaciers become inactive their coarse material, which was formerly bound by ice, may be released into the sediment cascade, whereas accelerating or rapidly downwasting rock glaciers may either

  13. Differential lymphocyte and antibody responses in deer mice infected with Sin Nombre hantavirus or Andes hantavirus.

    Science.gov (United States)

    Schountz, Tony; Quackenbush, Sandra; Rovnak, Joel; Haddock, Elaine; Black, William C; Feldmann, Heinz; Prescott, Joseph

    2014-08-01

    Hantavirus cardiopulmonary syndrome (HCPS) is a rodent-borne disease with a high case-fatality rate that is caused by several New World hantaviruses. Each pathogenic hantavirus is naturally hosted by a principal rodent species without conspicuous disease and infection is persistent, perhaps for life. Deer mice (Peromyscus maniculatus) are the natural reservoirs of Sin Nombre virus (SNV), the etiologic agent of most HCPS cases in North America. Deer mice remain infected despite a helper T cell response that leads to high-titer neutralizing antibodies. Deer mice are also susceptible to Andes hantavirus (ANDV), which causes most HCPS cases in South America; however, deer mice clear ANDV. We infected deer mice with SNV or ANDV to identify differences in host responses that might account for this differential outcome. SNV RNA levels were higher in the lungs but not different in the heart, spleen, or kidneys. Most ANDV-infected deer mice had seroconverted 14 days after inoculation, but none of the SNV-infected deer mice had. Examination of lymph node cell antigen recall responses identified elevated immune gene expression in deer mice infected with ANDV and suggested maturation toward a Th2 or T follicular helper phenotype in some ANDV-infected deer mice, including activation of the interleukin 4 (IL-4) pathway in T cells and B cells. These data suggest that the rate of maturation of the immune response is substantially higher and of greater magnitude during ANDV infection, and these differences may account for clearance of ANDV and persistence of SNV. Hantaviruses persistently infect their reservoir rodent hosts without pathology. It is unknown how these viruses evade sterilizing immune responses in the reservoirs. We have determined that infection of the deer mouse with its homologous hantavirus, Sin Nombre virus, results in low levels of immune gene expression in antigen-stimulated lymph node cells and a poor antibody response. However, infection of deer mice with a

  14. Reflections on Andes' Goal-Free User Interface

    Science.gov (United States)

    VanLehn, Kurt

    2016-01-01

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

  15. Gastrointestinal parasites of Lamas in the Bolivian Andes

    DEFF Research Database (Denmark)

    Nissen, Anne Malene; Nees, Ellinor Spörndly; Monrad, Jesper

    A cross sectional study was conducted to determine prevalences and intensities of gastrointestinal (GIT) parasites in lamas in the Bolivian Andes. A quantitative and qualitative necro-copro-parasitlogical study was performed on 33 lamas between October and December 2007. At the time of necropsy t...

  16. Molecular and biological characterization of Potato mop-top virus (PMTV, Pomovirus) isolates from potato-growing regions in Colombia

    DEFF Research Database (Denmark)

    Gil, José; Adams, Ian; Boonham, Neil

    2016-01-01

    Potato mop-top virus (PMTV) causes necrotic flecks inside and on tubers in temperate countries. In South America, these symptoms have not been observed, although the presence of the virus has been confirmed in the Andes and in Central America. To characterize PMTV isolates from the Andes, soil...... samples were taken from the main potato-producing regions in Colombia and virus was recovered by planting Nicotiana benthamiana as bait plants. The complete genomes of five isolates were sequenced and three of the isolates were inoculated to four different indicator plants. Based on sequence comparisons...

  17. Tectonics, hydrothermal zoning, and uranium in the central Andes

    Energy Technology Data Exchange (ETDEWEB)

    Gabelman, J W

    1961-01-01

    The geological features of the Peruvian Andes are discussed in some detail. The geologic history of the Andrean tectonics was found to be virtually the same as that represented in both North and South American Cordillera. The study indicated that Andrean hydrothermal mineralization occurred intermittently but in close time relation with accompanying deformations from the late Cretaceous or early Tertiary up to the present. The mineralization cycle is discussed as it relates to several metals, particularly uranium. Uranium is believed to occupy the same several temperature--environmental positions in the Andes that it does throughout the rest of the western hemisphere Cordillera. Even though uranium is present in minor quantities in several high-to-moderate-temperature environments, the bulk of uranium present in the cycle is believed to precipitate in the subepithermal environment.

  18. Glacier shrinkage and water resources in the Andes

    Science.gov (United States)

    Francou, Bernard; Coudrain, Anne

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

  19. Geochemical composition of river loads in the Tropical Andes: first insights from the Ecuadorian Andes

    Science.gov (United States)

    Tenorio Poma, Gustavo; Govers, Gerard; Vanacker, Veerle; Bouillon, Steven; Álvarez, Lenín; Zhiminaicela, Santiago

    2015-04-01

    Processes governing the transport of total suspended material (TSM), total dissolved solids (TDS) and particulate organic carbon (POC) are currently not well known for Tropical Andean river systems. We analyzed the geochemical behavior and the budgets of the particulate and dissolved loads for several sub-catchments in the Paute River basin in the southern Ecuadorian Andes, and examined how anthropogenic activities influenced the dynamics of riverine suspended and dissolved loads. We gathered a large dataset by regularly sampling 8 rivers for their TSM, POC, and TDS. Furthermore, we determined the major elements in the dissolved load and stable isotope composition (δ13C) of both the POC, and the dissolved inorganic carbon (DIC). The rivers that were sampled flow through a wide range of land uses including: 3 nature conservation areas (100 - 300 Km²), an intensive grassland and arable zone (142 Km²); downstream of two cities (1611 and 443 Km²), and 2 degraded basins (286 and 2492 Km²). We described the geochemical characteristics of the river loads both qualitatively and quantitatively. Important differences in TSM, POC and TDS yields were found between rivers: the concentration of these loads increases according with human activities within the basins. For all rivers, TSM, TDS and POC concentrations were dependent on discharge. Overall, a clear relation between TSM and POC (r²=0.62) was observed in all tributaries. The C:N ratios and δ13CPOC suggest that the POC in most rivers is mainly derived from soil organic matter eroded from soils dominated by C3 vegetation (δ13CPOC < -22‰). Low Ca:Si ratios (<1)and high δ13CDIC (-9 to -4) in the Yanuncay, Tomebamba1 and Machángara, rivers suggest that weathering of silica rocks is dominant in these catchments, and that the DIC is mainly derived from the soil or atmospheric CO2. In contrast, the Ca:Si ratio was high for the Burgay and Jadán rivers (1-13), and the low δ13CDIC values (-9 to -15) suggest that

  20. Steady-state exhumation pattern in the central Andes SE Peru

    NARCIS (Netherlands)

    Ruiz, G.M.H.; Carlotto, V.; van Heiningen, P.S.; Andriessen, P.A.M.

    2009-01-01

    The Western Cordillera of SE Peru is part of the Central Andes and is situated to the west of the Eastern Andes from which it is separated by the northern termination of the Altiplano - the Inter-Andean Valley. It is a volcanic-volcano-detrital chain that developed in the Palaeogene, and is

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

    Science.gov (United States)

    Barros, Agustina; Monz, Christopher; Pickering, Catherine

    2015-03-01

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

  2. Dynamics of a Puelche foehn event in the Andes

    Directory of Open Access Journals (Sweden)

    Lea Beusch

    2018-01-01

    Full Text Available In this numerical modelling study, we investigate a Puelche foehn event (25–26 March 2014 in the southern Andes – a region with sparse observations. The synoptic environment as well as the mesoscale structure and the dynamics of the easterly wind are examined with European Centre for Medium-Range Weather Forecasts (ECMWF analyses and a simulation with the mesoscale non-hydrostatic limited-area weather prediction model COSMO with a grid spacing of 2.2 km.The large-scale synoptic situation leading to this Puelche event is characterized by a mid-tropospheric cut-off low above the mountain range, the formation of a coastal surface low, as well as high pressure extending over the southern Andes. Easterly winds extend throughout the entire troposphere, indicative of a deep foehn flow. In the free troposphere, the easterlies are geostrophically balanced and develop in association with increasing pressure to the south. In contrast, within the planetary boundary layer, the easterly winds occur predominantly due to an increasing cross-range large-scale pressure gradient with only a weak geostrophic component. Kinematic trajectories indicate that a significant part of the Puelche air mass originates from above an inversion on the upstream side of the Andes. Some air parcels, however, ascend on the upstream side to crest height as the boundary layer deepens during daytime and/or flow through gaps across the mountain range. Hence, this Puelche event shares characteristics of both a blocked and a non-blocked foehn type.

  3. Memoria de los Andes, memoria de la naturaleza

    OpenAIRE

    Usselmann, Pierre

    2013-01-01

    Hace más de 35 años, terminando su tesis (1965), OlivierDollfus destacó la importancia de los Andes, “inmenso ysuntuoso campo”, para futuras investigaciones. En ese entonces sus estudios trataban de la geomorfología; escribía que “una de sus razones de ser es justamente este vaivén constante entre la observación de los procesos actuales y el intento de explicación, es decir el análisis de las formas heredadas” (1964). Esta preocupación, esta noción de memoria de la naturaleza, complementaria ...

  4. Tectonic control of erosion in the southern Central Andes

    Science.gov (United States)

    Val, Pedro; Venerdini, Agostina L.; Ouimet, William; Alvarado, Patricia; Hoke, Gregory D.

    2018-01-01

    Landscape evolution modeling and global compilations of exhumation data indicate that a wetter climate, mainly through orographic rainfall, can govern the spatial distribution of erosion rates and crustal strain across an orogenic wedge. However, detecting this link is not straightforward since these relationships can be modulated by tectonic forcing and/or obscured by heavy-tailed frequencies of catchment discharge. This study combines new and published along-strike average rates of catchment erosion constrained by 10Be and river-gauge data in the Central Andes between 28°S and 36°S. These data reveal a nearly identical latitudinal pattern in erosion rates on both sides of the range, reaching a maximum of 0.27 mm/a near 34°S. Collectively, data on topographic and fluvial relief, variability of rainfall and discharge, and crustal seismicity suggest that the along-strike pattern of erosion rates in the southern Central Andes is largely independent of climate, but closely relates to the N-S distribution of shallow crustal seismicity and diachronous surface uplift. The consistently high erosion rates on either side of the orogen near 34°S imply that climate plays a secondary role in the mass flux through an orogenic wedge where the perturbation to base level is similar on both sides.

  5. Infection of human monocyte-derived dendritic cells by ANDES Hantavirus enhances pro-inflammatory state, the secretion of active MMP-9 and indirectly enhances endothelial permeability

    Directory of Open Access Journals (Sweden)

    Lopez-Lastra Marcelo

    2011-05-01

    Full Text Available Abstract Background Andes virus (ANDV, a rodent-borne Hantavirus, is the major etiological agent of Hantavirus cardiopulmonary syndrome (HCPS in South America, which is mainly characterized by a vascular leakage with high rate of fatal outcomes for infected patients. Currently, neither specific therapy nor vaccines are available against this pathogen. ANDV infects both dendritic and epithelial cells, but in despite that the severity of the disease directly correlates with the viral RNA load, considerable evidence suggests that immune mechanisms rather than direct viral cytopathology are responsible for plasma leakage in HCPS. Here, we assessed the possible effect of soluble factors, induced in viral-activated DCs, on endothelial permeability. Activated immune cells, including DC, secrete gelatinolytic matrix metalloproteases (gMMP-2 and -9 that modulate the vascular permeability for their trafficking. Methods A clinical ANDES isolate was used to infect DC derived from primary PBMC. Maturation and pro-inflammatory phenotypes of ANDES-infected DC were assessed by studying the expression of receptors, cytokines and active gMMP-9, as well as some of their functional status. The ANDES-infected DC supernatants were assessed for their capacity to enhance a monolayer endothelial permeability using primary human vascular endothelial cells (HUVEC. Results Here, we show that in vitro primary DCs infected by a clinical isolate of ANDV shed virus RNA and proteins, suggesting a competent viral replication in these cells. Moreover, this infection induces an enhanced expression of soluble pro-inflammatory factors, including TNF-α and the active gMMP-9, as well as a decreased expression of anti-inflammatory cytokines, such as IL-10 and TGF-β. These viral activated cells are less sensitive to apoptosis. Moreover, supernatants from ANDV-infected DCs were able to indirectly enhance the permeability of a monolayer of primary HUVEC. Conclusions Primary human DCs

  6. Oroclinal Bending and Mountain Uplift in the Central Andes

    Science.gov (United States)

    Mpodozis, C.; Arriagada, C.; Roperch, P.

    2007-05-01

    The large paleomagnetic database now available for the Central Andes permits a good understanding of the overall spatial and temporal variations of rotations. Mesozoic to Early Paleogene rocks along the forearc of northern Chile (23°-28°S) record significant clockwise rotations (>25°) [Arriagada et al., 2006, Tectonics, doi:10.1029/2005TC001923]. Along the forearc of southern Peru, counterclockwise rotations recorded within flat lying red-beds (Moquegua Formation) increase from about -30° at 17.5°S to - 45° at15.5°S and decrease through time from the late Eocene to the late Oligocene-early Miocene [Roperch et al., 2006, Tectonics, doi:10.1029/2005TC001882]. Recently published thermo-chronological studies show evidence for strong exhumation within Bolivian Eastern Cordillera and the Puna plateau starting in the Eocene while structural studies indicate that the majority of crustal shortening in the Eastern Cordillera occurred during the Eocene-Oligocene, although the final stages of deformation may have continued through the Early Miocene. Rotations in the Peruvian and north Chilean forearc thus occurred at the same time than deformation and exhumation/uplift within the Eastern Cordillera. In contrast Neogene forearc rocks in southern Peru and northern Chile do not show evidences of rotation but low magnitude (10°) counterclockwise rotations are usually found in mid to late Miocene rocks from the northern Altiplano. These Neogene rotations are concomitant with shortening in the Sub-Andean zone and sinistral strike-slip faulting along the eastern edge of the northern Altiplano. We interpret the rotation pattern along the southern Peru and north Chile forearc as a result of strong late Eocene- late Oligocene oroclinal bending of the Central Andes associated with shortening gradients along the Eastern Cordillera associated both with the Abancay deflection and the Arica bend. The amount and spatial distribution of pre-Neogene shortening needed to account for

  7. AREAS OF ENDEMISM IN THE SOUTHERN CENTRAL ANDES

    Directory of Open Access Journals (Sweden)

    Lone Aagesen

    2012-01-01

    Full Text Available Este trabajo analiza la distribución de especies de plantas vasculares endémicas de la porción sur de los Andes centrales (sudoeste de Bolivia y noroeste de Argentina. En el análisis se incluyeron 540 especies endémicas de la región estudiada (aproximadamente 720.600 km2. La mayoría de las especies endémicas se halla en ambientes semiáridos, entre 1500-3500 m s.m., encontrándose principalmente en valles, laderas y mesetas del topográficamente complejo sur de los Andes centrales. Las áreas de endemismos aquí halladas se presentan consecuentemente en ambientes áridos y no en ambientes húmedos subtropicales de las Yungas tucumano-bolivianas, a pesar de que en esta última región la diversidad de plantas vasculares es mayor. Se identificaron un total de 17 patrones de distribución bien definidos, y parcialmente solapados. El patrón de distribución más amplio define un área general de endemismos para los Andes centrales. Esta área se extiende a lo largo de casi toda la región y está delimitada por especies que se distribuyen en ambientes desérticos a sub-húmedos en laderas, valles o regiones altoandinas. Casi todas las restantes áreas de endemismo se encuentran anidadas dentro del patrón de distribución amplio antes citado, superponiéndose en el sentido norte-sur a lo largo de pendientes y valles de los Andes y de las Sierras Pampeanas. A pesar del sesgo observado en la distribución hacia ambientes áridos, aproximadamente la mitad de las especies endémicas están restringidas a unas pocas áreas de alto endemismo, las que se encuentran en yuxtaposición con las zonas más lluviosas de la región. Estas áreas de alto endemismo incluyen los rangos de hábitat más amplios de la región en términos de altitud y precipitación, siendo las especies endémicas igualmente variables en sus requerimientos de humedad y elevación. Las unidades fitogeográficas previamente definidas por diversos autores no fueron encontradas

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

    Science.gov (United States)

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

    2016-04-01

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

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

    International Nuclear Information System (INIS)

    Akimkin, V.; Wiebe, D.; Pavlyuchenkov, Ya.; Zhukovska, S.; Semenov, D.; Henning, Th.; Vasyunin, A.; Birnstiel, T.

    2013-01-01

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

  10. Glacial lakes of the Central and Patagonian Andes

    Science.gov (United States)

    Wilson, Ryan; Glasser, Neil F.; Reynolds, John M.; Harrison, Stephan; Anacona, Pablo Iribarren; Schaefer, Marius; Shannon, Sarah

    2018-03-01

    The prevalence and increased frequency of high-magnitude Glacial Lake Outburst Floods (GLOFs) in the Chilean and Argentinean Andes suggests this region will be prone to similar events in the future as glaciers continue to retreat and thin under a warming climate. Despite this situation, monitoring of glacial lake development in this region has been limited, with past investigations only covering relatively small regions of Patagonia. This study presents new glacial lake inventories for 1986, 2000 and 2016, covering the Central Andes, Northern Patagonia and Southern Patagonia. Our aim was to characterise the physical attributes, spatial distribution and temporal development of glacial lakes in these three sub-regions using Landsat satellite imagery and image datasets available in Google Earth and Bing Maps. Glacial lake water volume was also estimated using an empirical area-volume scaling approach. Results reveal that glacial lakes across the study area have increased in number (43%) and areal extent (7%) between 1986 and 2016. Such changes equate to a glacial lake water volume increase of 65 km3 during the 30-year observation period. However, glacial lake growth and emergence was shown to vary sub-regionally according to localised topography, meteorology, climate change, rate of glacier change and the availability of low gradient ice areas. These and other factors are likely to influence the occurrence of GLOFs in the future. This analysis represents the first large-scale census of glacial lakes in Chile and Argentina and will allow for a better understanding of lake development in this region, as well as, providing a basis for future GLOF risk assessments.

  11. Late Pleistocene glacial fluctuations in Cordillera Oriental, subtropical Andes

    Science.gov (United States)

    Martini, Mateo A.; Kaplan, Michael R.; Strelin, Jorge A.; Astini, Ricardo A.; Schaefer, Joerg M.; Caffee, Marc W.; Schwartz, Roseanne

    2017-09-01

    The behavior of subtropical glaciers during Middle to Late Pleistocene global glacial maxima and abrupt climate change events, specifically in Earth's most arid low-latitude regions, remains an outstanding problem in paleoclimatology. The present-day climate of Cordillera Oriental, in arid northwestern Argentina, is influenced by shifts in subtropical climate systems, including the South American Summer Monsoon. To understand better past glacier-subtropical climates during the global Last Glacial Maximum (LGM, 26.5-19 ka) and other time periods, we combined geomorphic features with forty-two precise 10Be ages on moraine boulders and reconstructed paleo-equilibrium line altitudes (ELA) at Nevado de Chañi (24°S) in the arid subtropical Andes. We found a major glacial expansion at ∼23 ± 1.6 ka, that is, during the global LGM. Additional glacial expansions are observed before the global LGM (at ∼52-39 ka), and after, at 15 ± 0.5 and 12 ± 0.6 ka. The ∼15 ka glacial event was found on both sides of Chañi and the ∼12 ka event is only recorded on the east side. Reconstructed ELAs of the former glaciers exhibit a rise from east to west that resembles the present subtropical climate trajectory from the Atlantic side of the continent; hence, we infer that this climate pattern must have been present in the past. Based on comparison with other low-latitude paleoclimate records, such as those from lakes and caves, we infer that both temperature and precipitation influenced past glacial occurrence in this sector of the arid Andes. Our findings also imply that abrupt deglacial climate events associated with the North Atlantic, specifically curtailed meridional overturning circulation and regional cooling, may have had attendant impacts on low subtropical Southern Hemisphere latitudes, including the climate systems that affect glacial activity around Nevado de Chañi.

  12. Adaptive institutions? Peasant institutions and natural models facing climatic and economic changes in the Colombian Andes

    NARCIS (Netherlands)

    Feola, Giuseppe

    2017-01-01

    In the Colombian Andes, peasants have co-evolved with their environment for centuries, but it is uncertain whether traditional informal institutions and natural models are adapting to current and possibly unprecedented economic and climatic disturbances. This study investigated institutional

  13. Litterfall production under pine plantations in the southern Andes region of Ecuador

    Directory of Open Access Journals (Sweden)

    Pablo Quichimbo

    2016-09-01

    Full Text Available Litterfall research is an interesting aspect in environmental studies due to its significance in nutrient cycling specially in regions like the Andes where the interactions between biomass production and its decomposition is poorly understood. This study is focusing in the litterfall biomass production under pine plantations in southern Ecuador. The litterfall production was studied for five months at two-week intervals in three pine forest sites located in the southern Andes region of Ecuador. Monthly litterfall production ranged between 1067-1907 kg ha-1, in comparison with other coniferous stands around the world, this study revealed a higher litterfall production for tropical areas and particularly the highest production under pine plantations in the Andes region. This high litterfall production highlights the upmost importance of this forest component as a potential nutrient reservoir involved in the global nutrient cycling under landscapes dominated by this exotic forest specie in the tropical Andes.

  14. A new species of Trechisibus from Peruvian Andes (Coleoptera: Carabidae, Trechinae

    Directory of Open Access Journals (Sweden)

    Pedro Delgado

    2016-06-01

    Full Text Available In this work the new species Trechisibus (s. str. delestali sp. n., is described from the southern Peruvian Andes. The morphological differences with the geographically closest species of the subgenus are also presented and discussed.

  15. New ICT in the Peruvian Andes: Theoretical Foundation and Bibliographical Balance

    Directory of Open Access Journals (Sweden)

    Mario Sánchez-Dávila

    2016-04-01

    Full Text Available On the one hand, this paper explains the theoretical foundations on which this proposal for digital anthropology in the Peruvian Andes is based (on the origins of digital anthropology, discussions on oral and written technology, and theories of digital technology as social practice. And, on the other hand, this paper presents a bibliographical balance of the studies on the new ICT in the Peruvian Andes (on identity expression, productive development and formal education in the Andean world.

  16. An elusive new species of Marsupial Frog (Anura: Hemiphractidae: Gastrotheca from the Andes of northern Peru

    Directory of Open Access Journals (Sweden)

    William E. Duellman

    2013-06-01

    Full Text Available A new species of marsupial frog, genus Gastrotheca, is described from high-elevation grasslands in the Andes in Región Amazonas in northernPeru, where even calling males are well hidden in deep moss. The new species is distinguished from all congeners by its unique color pattern that includes a narrow, blackbordered, yellow middorsal stripe. The species apparently belongs to the Gastrotheca plumbea Group, which ranges in the Andes from northern Colombia to northern Peru.

  17. Ebola Virus and Marburg Virus

    Science.gov (United States)

    Ebola virus and Marburg virus Overview Ebola virus and Marburg virus are related viruses that cause hemorrhagic fevers — illnesses marked by severe bleeding (hemorrhage), organ failure and, in many ...

  18. Recursos hídricos en los Andes: Lago Titicaca

    Directory of Open Access Journals (Sweden)

    1995-01-01

    Full Text Available RESSOURCES EN EAUX DANS LES ANDES : LAC TITICACA. Une analyse par régression a été menée entre les variations de niveau du Lac Titicaca et les entrées du système (apports des affluents et précipitations. Les coefficients de corrélation, quoique relativement faibles, montrent aux abords du lac un effet de persistance qui diminue lorsque les stations sont éloignées du plan d’eau. L’inertie du lac se manifeste l’année suivante pour les affluents du lac et évidemment pour le lac lui-même. Ces résultats confirment la présence d’un mécanisme de rétro alimentation (effet boomerang. Cela montre que le système du Lac Titicaca est fragile, face à une utilisation excessive de ses eaux. Las regresiones estudiadas de cambios de nivel en el lago Titicaca contra precipitaciones y aportes en su cuenca, aunque relativamente bajas, muestran un efecto de persistencia en las proximidades del lago que decrece conforme las estaciones se alejan de éste. Lo que evidencia que la inercia del lago se manifiesta en el período siguiente (lag uno en los afluentes del lago y obviamente en el propio lago, fenómeno que parece confirmar la presencia de un mecanismo de retroalimentación (efecto boomerang. Este comportamiento muestra la fragilidad del lago frente a un aprovechamiento consuntivo excesivo. WATER RESOURCES IN THE ANDES: LAKE TITICACA. The studied regressions of the level changes in the Lake Titicaca versus the rainfall and the runoff in the basin, even being relatively low, show an effect of persistence in the proximity of the lake which decreases as we go away from it. This makes evident that the lake inertia manifests itself the following period (lag one in the lake tributaries and obviously in the lake itself, phenomenon which seems to confirm the presence of a feedback mechanism (boomerang effect. This behaviour shows the fragility of the lake against the excessive consumptive uses of the waters in its basin.

  19. Hamster-Adapted Sin Nombre Virus Causes Disseminated Infection and Efficiently Replicates in Pulmonary Endothelial Cells without Signs of Disease

    OpenAIRE

    Safronetz, David; Prescott, Joseph; Haddock, Elaine; Scott, Dana P.; Feldmann, Heinz; Ebihara, Hideki

    2013-01-01

    To date, a laboratory animal model for the study of Sin Nombre virus (SNV) infection or associated disease has not been described. Unlike infection with Andes virus, which causes lethal hantavirus pulmonary syndrome (HPS)-like disease in hamsters, SNV infection is short-lived, with no viremia and little dissemination. Here we investigated the effect of passaging SNV in hamsters. We found that a host-adapted SNV achieves prolonged and disseminated infection in hamsters, including efficient rep...

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

    Science.gov (United States)

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

    2009-01-01

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

  1. Meteorological Conditions of Floods In The Chilean Andes Mountains

    Science.gov (United States)

    Vergara, J.

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

  2. Relationships between mineralization and silicic volcanism in the central Andes

    Energy Technology Data Exchange (ETDEWEB)

    Francis, P.W.; Halls, C.; Baker, M.C.W.

    1983-10-01

    Studies of late Tertiary silicic volcanic centers in the Western and Eastern Cordilleras of the Central Andes show that three volcanic environments are appropriate sites for mineralization: (1) ring-fracture extrusions post-dating large calderas; (2) similar extrusions within ignimbrite shields; and (3) isolated, small silicic volcanoes. Subvolcanic tin mineralization in the Eastern Cordillera is located in silicic stocks and associated breccias of Miocene age. The Cerro Rico stock, Potosi, Bolivia, contains tin and silver mineralization and has an intrusion age apparently millions of years younger than that of the associated Kari Kari caldera. Similar age relationships between mineralization and caldera formation have been described from the San Juan province, Colorado. The vein deposits of Chocaya, southern Bolivia, were emplaced in the lower part of an ignimbrite shield, a type of volcanic edifice as yet unrecognized in comparable areas of silicic volcanism. The El Salvador porphyry copper deposit, Chile, is related to silicic stocks which may have been intruded along a caldera ring fracture. Existing models for the genesis of porphyry copper deposits suggest that they formed in granodioritic stocks located in the infrastructure of andesitic stratovolcanoes. The dome of La Soufriere, Guadeloupe is proposed as a modern analog for the surface expression of subvolcanic mineralization processes, the phreatic eruptions there suggesting the formation of hydrothermal breccia bodies in depth.

  3. Fragmentation of Andes-to-Amazon connectivity by hydropower dams.

    Science.gov (United States)

    Anderson, Elizabeth P; Jenkins, Clinton N; Heilpern, Sebastian; Maldonado-Ocampo, Javier A; Carvajal-Vallejos, Fernando M; Encalada, Andrea C; Rivadeneira, Juan Francisco; Hidalgo, Max; Cañas, Carlos M; Ortega, Hernan; Salcedo, Norma; Maldonado, Mabel; Tedesco, Pablo A

    2018-01-01

    Andes-to-Amazon river connectivity controls numerous natural and human systems in the greater Amazon. However, it is being rapidly altered by a wave of new hydropower development, the impacts of which have been previously underestimated. We document 142 dams existing or under construction and 160 proposed dams for rivers draining the Andean headwaters of the Amazon. Existing dams have fragmented the tributary networks of six of eight major Andean Amazon river basins. Proposed dams could result in significant losses in river connectivity in river mainstems of five of eight major systems-the Napo, Marañón, Ucayali, Beni, and Mamoré. With a newly reported 671 freshwater fish species inhabiting the Andean headwaters of the Amazon (>500 m), dams threaten previously unrecognized biodiversity, particularly among endemic and migratory species. Because Andean rivers contribute most of the sediment in the mainstem Amazon, losses in river connectivity translate to drastic alteration of river channel and floodplain geomorphology and associated ecosystem services.

  4. Bofedales: high altitude peatlands of the central Andes Bofedales: turberas de alta montaña de los Andes centrales

    Directory of Open Access Journals (Sweden)

    FRANCISCO A SQUEO

    2006-06-01

    Full Text Available There is an exceptional group of alpine peatlands in the world situated in the arid grasslands of the central Andes. The peatlands in northern Chile occur in the most arid part of their range. Members of the Juncaceae are the primary peat-forming plant species. Fresh and mildly saline groundwaters originate from glaciers, snowmelt and rain are the water sources for the northern Chile peatlands. Paleoecological investigations suggest that some peatlands are recent features of the landscape having developed within the last three thousand years or less. These peatlands are unique, extremely fragile water features sensitive to climate changes and human disturbances such as regional mining activity. Much more work is required to develop scientifically based sound management and conservation programs for the rare plants and animals that live in them and to ensure the future livelihoods of the indigenous peoples who depend on themExiste un grupo excepcional de turberas (bofedales de alta montaña en el mundo situados en la estepa árida de los Andes centrales. Los bofedales en el norte de Chile están presentes en la parte más árida de su rango. Las principales especies de plantas responsables de la formación de turba corresponden a miembros de Juncaceae. El agua fresca y medianamente salina de los bofedales proviene de agua subterránea asociada a riachuelos proveniente de glaciares, derretimiento de nieve y lluvia. Investigaciones paleoecológicas sugieren que algunos bofedales son integrantes recientes del paisaje, habiéndose desarrollado durante los últimos tres mil años o menos. Estos bofedales son entidades únicas, extremadamente frágiles por su dependencia del agua, sensibles a los cambios climáticos y vulnerables a la alteración humana tal como la actividad minera en la región. Se requiere mucho más trabajo para desarrollar programas de manejo y conservación, con sólidas bases científicas, de las plantas y animales que viven en

  5. Linchamientos y conflicto político en Los Andes Lynchings and Political conflict in The Andes

    Directory of Open Access Journals (Sweden)

    Carlos M. Vilas

    2007-06-01

    Full Text Available En 2004, los alcaldes de dos municipalidades de la región aimara de los Andes fueron linchados en la aparente culminación de agudos conflictos políticos internos y entre las respectivas comunidades y el Estado central. En este artículo se discuten ambos casos con el fin de ilustrar las transformaciones experimentadas en años recientes en la organización y la dinámica interna de las comunidades andinas, y de la articulación conflictiva de la política local en los procesos e instituciones de más amplio alcance. Precariedad social e incapacidad o renuencia del Estado para responder con eficacia a demandas básicas de determinados grupos de población configuran enmarcamientos socioeconómicos e institucionales de los linchamientos. En contraste con enfoques que enfatizan en factores culturales tradicionales o en un supuesto nacionalismo indígena, en el artículo se destaca la gravitación de fenómenos y procesos político- institucionales recientes en la transformación cultural y política de las comunidades, en el modo en que éstas procesan sus conflictos internos y con el Estado central.In 2004, two municipalitys mayors form the aimara Andes of Peru and Bolivia were subjected to mass lynchings as a result of the apparent culmination of violent political confrontations. This paper deals with these events as dramatic illustrations of the transformations the Andean communities experienced during recent decades in their internal dynamics, as well as in the articulation of local politics to processes and institutions beyond the communal limits. Structural precariousness combined with the state's inability or reluctance to come to terms with social or political demands from relevant segments of the people in the communities set the socioeconomic and institutional stage for lynchings. In contrast with approaches relating these events to an alleged indigenous cultural identity, the analysis points to the impact of the communities' political

  6. A fusion-inhibiting peptide against Rift Valley fever virus inhibits multiple, diverse viruses.

    Directory of Open Access Journals (Sweden)

    Jeffrey W Koehler

    Full Text Available For enveloped viruses, fusion of the viral envelope with a cellular membrane is critical for a productive infection to occur. This fusion process is mediated by at least three classes of fusion proteins (Class I, II, and III based on the protein sequence and structure. For Rift Valley fever virus (RVFV, the glycoprotein Gc (Class II fusion protein mediates this fusion event following entry into the endocytic pathway, allowing the viral genome access to the cell cytoplasm. Here, we show that peptides analogous to the RVFV Gc stem region inhibited RVFV infectivity in cell culture by inhibiting the fusion process. Further, we show that infectivity can be inhibited for diverse, unrelated RNA viruses that have Class I (Ebola virus, Class II (Andes virus, or Class III (vesicular stomatitis virus fusion proteins using this single peptide. Our findings are consistent with an inhibition mechanism similar to that proposed for stem peptide fusion inhibitors of dengue virus in which the RVFV inhibitory peptide first binds to both the virion and cell membranes, allowing it to traffic with the virus into the endocytic pathway. Upon acidification and rearrangement of Gc, the peptide is then able to specifically bind to Gc and prevent fusion of the viral and endocytic membranes, thus inhibiting viral infection. These results could provide novel insights into conserved features among the three classes of viral fusion proteins and offer direction for the future development of broadly active fusion inhibitors.

  7. Primer registro del frutero pechinegro Pipreola lubomirskii (Aves, Cotingidae en la vertiente occidental de los Andes

    Directory of Open Access Journals (Sweden)

    Letty Salinas

    2013-06-01

    Full Text Available El frutero pechinegro, Pipreola lubomirskii, es un cotíngido registrado como raro y de distribución local en los Andes del Norte. Antes del presente registro sólo había sido reportado para la vertiente oriental del Perú y Ecuador, así como los Andes del sur de Colombia. El presente registro amplia su distribución a los bosques montañosos de la vertiente occidental de los Andes peruanos, habiéndose encontrado en los bosques nublados del valle del río Zaña, en el departamento de Cajamarca (6º50’-6º52’ latitud S, 79º10’-79º07’ longitud O.

  8. Carbon stabilization mechanisms in soils in the Andes

    Science.gov (United States)

    Jansen, Boris; Cammeraat, Erik

    2015-04-01

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

  9. Long-term carbon accumulation in Andes peatlands

    Science.gov (United States)

    Huaman, Yizet; Moreira-turq, Patricia; Willems, Bram; Espinoza, Raul; Turq, Bruno; Apaéstegui, James; Llanos, Romina

    2017-04-01

    High-altitude peatlands of the Andes still remain relatively unexplored since most of the studies on carbon capture in tropical soils have focused on peatlands in low altitude areas, leaving aside the importance of the study of high mountain wetlands, currently called "bofedales" located between 3000 and 5000 masl, covering most of the Andes mountains in South America. These peatlands in turn may also represent important paleoclimatic records. In this study, we investigated three peatland cores (APA-01, APA2-01, and APA2-02) at different altitudes (4210 m, 4420 m and 4432 m, respectively) in high Andean Peatlands of southern Peru. The peatland studied is located at the headwater basin Cachi River, in the town of Ayacucho, Peru. The aim of this study was to evaluate the role played by past climatic changes on the peatlands carbon accumulation. Each core was sectioned centimeter by centimeter and sub samples (n = 31) were collected for radiocarbon dating by AMS (acceleration mass spectrometer) and were used to create a sedimentological model based on the program Clam2.2R. The concentrations of carbon and nitrogen were determined from a C / H / N elemental analyzer and the stable carbon and nitrogen isotopes (δ13C and δ15N) were also analyzed. The bulk density was determined based on the volume occupied by the sediment (g /cm3). Finally, the carbon accumulation rate (gC m-2año-1) was determined. The three cores were characterized by two sedimentary units, the results present in the first sedimentary unit of APA01 an average long-term carbon accumulation rate of 59 gC m-2año-1, APA2-01 with 32 gC m-2año-1 and finally APA2-02 with 24 gC m-2año-1; for the second sedimentary unit we have: APA01 on average 17 gC m-2año-1, APA2-01 with 33 gC m-2año-1 and finally APA2-02 with 49 gC m-2año-1. In conclusion, we can say that the carbon accumulation rate for the first sedimentary unit of the three cores decreases as the altitude increases; on the other hand, we have the

  10. Morphologic evolution of the Central Andes of Peru

    Science.gov (United States)

    Gonzalez, Laura; Pfiffner, O. Adrian

    2012-01-01

    In this paper, we analyze the morphology of the Andes of Peru and its evolution based on the geometry of river channels, their bedrock profiles, stream gradient indices and the relation between thrust faults and morphology. The rivers of the Pacific Basin incised Mesozoic sediments of the Marañon thrust belt, Cenozoic volcanics and the granitic rocks of the Coastal Batholith. They are mainly bedrock channels with convex upward shapes and show signs of active ongoing incision. The changes in lithology do not correlate with breaks in slope of the channels (or knick points) such that the high gradient indices (K) with values between 2,000-3,000 and higher than 3,000 suggest that incision is controlled by tectonic activity. Our analysis reveals that many of the ranges of the Western Cordillera were uplifted to the actual elevations where peaks reach to 6,000 m above sea level by thrusting along steeply dipping faults. We correlate this uplift with the Quechua Phase of Neogene age documented for the Subandean thrust belt. The rivers of the Amazonas Basin have steep slopes and high gradient indices of 2,000-3,000 and locally more than 3,000 in those segments where the rivers flow over the crystalline basement of the Eastern Cordillera affected by vertical faulting. Gradient indices decrease to 1,000-2,000 within the east-vergent thrust belt of the Subandean Zone. Here a correlation between breaks in river channel slopes and location of thrust faults can be established, suggesting that the young, Quechua Phase thrust faults of the Subandean thrust belt, which involve Neogene sediments, influenced the channel geometry. In the eastern lowlands, these rivers become meandering and flow parallel to anticlines that formed in the hanging wall of Quechua Phase thrust faults, suggesting that the river courses were actively displaced outward into the foreland.

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

    Science.gov (United States)

    Pribilsky, Jason

    2001-01-01

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

  12. Millennial-scale vegetation changes in the tropical Andes using ecological grouping and ordination methods

    NARCIS (Netherlands)

    Urrego, D.H.; Hooghiemstra, H.; Rama-Corredor, O.; Martrat, B.; Grimalt, J.O.; Thompson, L.; Bush, M.B.; González-Carranza, Z.; Hanselman, J.; Valencia, B.; Velásquez-Ruiz, C.

    2016-01-01

    We compare eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the last 30 000 years, with particular emphasis on the Pleistocene to Holocene transition. We explore ecological grouping and downcore

  13. Vulnerability to climate change and community based adaptation in the Peruvian Andes, a stepwise approach

    NARCIS (Netherlands)

    Lasage, R.; Muis, S.; Sardella, C.S.E.; van Drunen, M.A.; Verburg, P.H.; Aerts, J.C.J.H.

    2015-01-01

    The livelihoods of people in the Andes are expected to be affected by climate change due to their dependence on glacier water. The observed decrease in glacier volume over the last few decades is likely to accelerate during the current century, which will affect water availability in the region.

  14. Macroinvertebrate community response to acid mine drainage in rivers of the High Andes (Bolivia).

    NARCIS (Netherlands)

    Damme, P.A. van; Hamel, C.; Ayala, A.; Bervoets, L.

    2008-01-01

    Several High Andes Rivers are characterized by inorganic water pollution known as acid mine drainage (AMD). The aim of this study was to assess the relationship between metal concentrations in the sediments and the macroinvertebrate communities in two river basins affected by AMD. In general, the

  15. High altitude C4 grasslands in the northern Andes: relicts from glacial conditions?

    NARCIS (Netherlands)

    Boom, A.; Mora, G.; Cleef, A.M.; Hooghiemstra, H.

    2001-01-01

    The altitudinal vegetation distribution in the northern Andes during glacial time differed from the present-day conditions as a result of temperature and precipitation change. New evidence indicate that as a response to a reduced atmospheric partial CO2 pressure (pCO2), the competitive balance

  16. Racialization of the Bilingual Student in Higher Education: A Case from the Peruvian Andes

    Science.gov (United States)

    Zavala, Virginia

    2011-01-01

    In the Andes, a phonological transference known as "motoseo" has acquired ideological weight. People think that bilingual speakers of Quechua and Spanish "confuse" the vowels when speaking Spanish and that they are inferior to the ones who do not. In this article, I analyze the ideological agenda of the racialized verbal…

  17. Transboundary protected area proposals along the Southern Andes of Chile and Argentina: Status of current efforts

    Science.gov (United States)

    Peter Keller

    2007-01-01

    An evolving network of protected areas along the southern Andes of Chile and Argentina-the heart of Patagonia-are in various stages of evaluation and potential Transboundary Protected Area designations. This paper examines three such efforts. The first proposal is the North Andean-Patagonia Regional Eco-Corridor, which was the subject of a recent bilateral meeting...

  18. Natural gas across the Andes : a case study of an international business venture

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa, E.B.; Smith, B.

    2002-07-01

    This book describes the challenges and complexities of constructing the GasAndes pipeline from Argentinian gas fields across the Andes to Santiago in Chile. The project was a joint international effort between Canada's NOVA Corporation, Chile's Gasco and Gener, and Argentina's Compania General de Combustibles and Techint Compania Tecnica Internacional. The book relates how NOVA Gas International, together with its partners, accomplished the task of constructing the first major natural gas pipeline across the Andes mountains despite significant challenges such as steep mountain slopes, many river crossings, high altitude, high winds and bitter cold. It describes how the partnership developed and how political and socio-economic issues were dealt with. It demonstrates how business practices were modified to deal with local conditions and to ensure that the fragile environment of the Andean meadows was protected. It also describes how the builders of the pipeline addressed the concerns of communities along the pipeline route. The pipeline was constructed at a time when democracy was returning and market economies were shifting from a reduced role of government in the energy sector. The 463 km GasAndes pipeline has been in operation since August 7, 1997. refs., tabs., figs.

  19. Angiosperm flora and biogeography of the páramo region of Colombia, northern Andes

    NARCIS (Netherlands)

    Londoño, C.; Cleef, A.; Madriñan, S.

    2014-01-01

    Páramo is the neotropical high elevation ecosystem in the northern Andes and Central America consisting of multiple dissected open areas above 3000 m a.s.l. Complex evolutionary processes that occurred within these ecosystems gave rise to a unique tropical Andean flora. Previous phytogeographical

  20. Hybrid Literacies: The Case of a Quechua Community in the Andes

    Science.gov (United States)

    de la Piedra, Maria Teresa

    2009-01-01

    Drawing on data from an ethnographic study in a Quechua rural community in the Peruvian Andes, this article examines hybrid literacy practices among bilingual rural speakers in the context of the household and the community. I examine the coexistence of two types of textual practices that operate side by side, at times integrated in the same…

  1. Distichia acicularis sp. nov. – a new cushion forming Juncaceae from the high Andes of Ecuador

    DEFF Research Database (Denmark)

    Balslev, Henrik; Lægaard, Simon

    1986-01-01

    Distichia acicularis is described as a new species of Juncaceae. It occurs in the high Andes of Ecuador between 3200 m and 4200 m above sea level. Its closest relative is D. muscoides Nees & Meyen from which it is distinct through its narrow, linear, mucronate leafblades and its 1–3 mm long...

  2. Drunken Speech and the Construction of Meaning: Bilingual Competence in the Southern Peruvian Andes.

    Science.gov (United States)

    Harvey, Penelope M.

    1991-01-01

    Examination of the language use of drunken speakers in a bilingual Southern Peruvian Andes community found that drunken speakers were less constrained in their linguistic choices by individual linguistic competence and of differential status between speaker and addressee, and they exploited the ambiguities in implicit social meanings that normally…

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

    Science.gov (United States)

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

    2007-05-15

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

  4. The forest vegetation of Ramal de Guaramacal in the Venezuelan Andes

    NARCIS (Netherlands)

    Cuello, A.N.L.; Cleef, A.M.

    2009-01-01

    Montane forest community composition of Ranial de Guaramacal, Venezuelan Andes, was studied along the altitudinal gradient on both sides of the range with different slope expositions. Thirty five 0.1 ha plots were Surveyed, with variable intervals of 30 to 150 meters between 1350 in and 2890 in and

  5. The forest vegetation of Ramal de Guaramacal in the Venezuelan Andes

    NARCIS (Netherlands)

    Cuello A., N.L.; Cleef, A.M.

    2009-01-01

    Montane forest community composition of Ramal de Guaramacal, Venezuelan Andes, was studied along the altitudinal gradient on both sides of the range with different slope expositions. Thirty five 0.1 ha plots were surveyed, with variable intervals of 30 to 150 meters between 1350 m and 2890 m and

  6. Palm harvest impact in the western Amazon, Andes and Pacific lowlands

    DEFF Research Database (Denmark)

    Balslev, Henrik

    2011-01-01

    Palms are the most useful group of plants in tropical American forests and in this project we study the effect of extraction and trade of palms on forests in the western Amazon, Andes, and Pacific lowlands. We determine the size of the resource by making palm community studies in the different...

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

    Science.gov (United States)

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

    2014-12-01

    The Yanesha are a Peruvian population who inhabit an environment transitional between the Andes and Amazonia. They present cultural traits characteristic of both regions, including in the language they speak: Yanesha belongs to the Arawak language family (which very likely originated in the Amazon/Orinoco lowlands), but has been strongly influenced by Quechua, the most widespread language family of the Andes. Given their location and cultural make-up, the Yanesha make for an ideal case study for investigating language and population dynamics across the Andes-Amazonia divide. In this study, we analyze data from high and mid-altitude Yanesha villages, both Y chromosome (17 STRs and 16 SNPs diagnostic for assigning haplogroups) and mtDNA data (control region sequences and 3 SNPs and one INDEL diagnostic for assigning haplogroups). We uncover sex-biased genetic trends that probably arose in different stages: first, a male-biased gene flow from Andean regions, genetically consistent with highland Quechua-speakers and probably dating back to Inca expansion; and second, traces of European contact consistent with Y chromosome lineages from Italy and Tyrol, in line with historically documented migrations. Most research in the history, archaeology and linguistics of South America has long been characterized by perceptions of a sharp divide between the Andes and Amazonia; our results serve as a clear case-study confirming demographic flows across that 'divide'. © 2014 The Authors. American journal of physical Anthropology published by Wiley Periodocals, Inc.

  8. Andes Virus M Genome Segment is Not Sufficient to Confer the Virulence Associated With Andres Virus in Syrian Hamsters

    National Research Council Canada - National Science Library

    McElroy, A

    2004-01-01

    ...) in North and South America, respectively. Although ANDV causes a lethal HPS-like disease in hamsters, SNV, and all other HPS-associated hantaviruses that have been tested, cause asymptomatic infections of laboratory animals, including hamsters...

  9. ECHO virus

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001340.htm ECHO virus To use the sharing features on this page, please enable JavaScript. Enteric cytopathic human orphan (ECHO) viruses are a group of viruses that can lead ...

  10. Hantavirus Gn and Gc glycoproteins self-assemble into virus-like particles.

    Science.gov (United States)

    Acuña, Rodrigo; Cifuentes-Muñoz, Nicolás; Márquez, Chantal L; Bulling, Manuela; Klingström, Jonas; Mancini, Roberta; Lozach, Pierre-Yves; Tischler, Nicole D

    2014-02-01

    How hantaviruses assemble and exit infected cells remains largely unknown. Here, we show that the expression of Andes (ANDV) and Puumala (PUUV) hantavirus Gn and Gc envelope glycoproteins lead to their self-assembly into virus-like particles (VLPs) which were released to cell supernatants. The viral nucleoprotein was not required for particle formation. Further, a Gc endodomain deletion mutant did not abrogate VLP formation. The VLPs were pleomorphic, exposed protrusions and reacted with patient sera.

  11. Palabras y silencios: la retórica del poder en los Andes

    Directory of Open Access Journals (Sweden)

    1997-01-01

    Full Text Available PAROLES ET SILENCES : LA RETHORIQUE DU POUVOIR DANS LES ANDES. La parole condense différents arguments et formes de pouvoir dans les sociétés andines. Le domaine social et le cadre cérémoniel appartiennent à ceux qui articulent bien les mots. La différenciation entre la valeur octroyée à la parole et celle correspondant aux silences implique diverses modalités de prestige de reconnaissance sociale et de pouvoir rituel dans les Andes. Les personnes, les vivants et les savants exercent une maîtrise subtile de la parole face aux étrangers, aux défunts et aux sots, qui demeurent socialement “muets”, silencieux. La palabra condensa diferentes argumentos y formas de poder en las sociedades andinas. El dominio social y el ámbito ceremonial pertenecen a los buenos articuladores de palabras. La diferenciación entre el valor otorgado a la palabra y el que corresponde a los silencios implica diferentes modalidades de prestigio, reconocimiento social y poder ritual en los Andes. Las personas, los vivos y los sabios ejercen un dominio exquisito de la palabra frente a los extraños, los difuntos y los “necios” que permanecen socialmente “mudos”, callados. WORDS AND SILENCES: THE RHETORIC OF POWER IN THE ANDES. Words have different meanings and means to exercise power in Andean societies. Social power and ceremonial environments belong people who are fluent in language. The difference between the value ascribed to the spoken word and that ascribed to silence implies several kinds of prestige, social recognition and ritual power in the Andes. “Ordinary”, alive and wise people exert an exquisite authority with words as compared with strange, dead and “stupid people” who remain socially 'dumb', silent.

  12. Un réseau d'observation des glaciers dans les Andes tropicales

    Directory of Open Access Journals (Sweden)

    1995-01-01

    Full Text Available Par leur grande sensibilité au changement climatique, les glaciers tropicaux sont d’excellents indicateurs de l’évolution du climat et, en même temps, des objets hydrologiques susceptibles d’évoluer rapidement dans le futur. On montre que l’actuel recul accéléré des glaciers dans les Andes centrales et les conséquences qu’il peut avoir en matière hydrologique et de risques naturels rendent nécessaire un programme de surveillance de ces glaciers au niveau de toute la chaîne, ce que l’ORSTOM contribue à faire depuis 1991. UNA RED DE OBSERVACIÓN DE LOS GLACIARES EN LOS ANDES TROPICALES. Por su gran sensibilidad al cambio climático, los glaciares tropicales son excelentes indicadores de la evolución del clima, así como objectos hidrológicos susceptibles de una evolución rápida en el futuro. Considerando el actual retroceso acelerado de los glaciares en los Andes centrales y las consecuencias que puede tener a nivel hidrológico así como en el campo de los riesgos naturales, es necesario un programa de monitoreo de los glaciares a nivel de toda la cordillera, que es lo que ORSTOM contribuye a hacer desde 1991. A GLACIER MONITORING NETWORK IN THE TROPICAL ANDES. The high sensibility of Tropical glaciers to climatic forcing make it possible to use them as reliable indicators of climate evolution, as well as hydrological systems which could change rapidly in the future. Considering the present increase in glacier retreat in central Andes and the consequences induced by this evolution on water resources and natural hazards, a monitoring program at a large scale appears to be highly desirable. This has been the objective of ORSTOM since 1991.

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

    Science.gov (United States)

    Sando, Steven Kent; Neitzert, Kathleen M.

    2003-01-01

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

  14. Screening for new accumulator plants in Andes Range mines

    Science.gov (United States)

    Bech, Jaume; Roca, Núria

    2016-04-01

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

  15. Holocene tephra-fall deposits of southern and austral Andes volcanic zones (33-54oS): eruption recurrence

    International Nuclear Information System (INIS)

    Naranjo, J.A.; Polanco, E.; Lara, L; Moreno, H; Stern, C.R

    2001-01-01

    Radiometric 14 C dating is a very useful tool to study the chronostratigraphy of pyroclastic deposits. In addition, 14 C ages are essential parameters for the estimation of the recurrence time of the explosive volcanic activity. The origin, distribution and relative age of mappable Holocene tephra-fall deposits of the Southern Andes Volcanic Zone (SVZ) and Austral Andes Volcanic Zone (AVZ) from 33 o S-54 o S, were studied and their recurrence period is analysed (au)

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

    Science.gov (United States)

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

    2016-10-25

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

  17. La implantación de la viruela en los Andes, la historia de un holocausto

    Directory of Open Access Journals (Sweden)

    Uriel García Cáceres

    2003-03-01

    Full Text Available La historia de las epidemias de viruela en los Andes tiene el carácter tétrico del relato de un holocausto. Esta presentación está destinada a resaltar las etapas más importantes del proceso de la implantación de la viruela en las poblaciones andinas en general y, en particular, en el Perú, desde principio del siglo XVI hasta nuestros días.

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

    Science.gov (United States)

    Engel, Zbyněk; Skrzypek, Grzegorz; Chuman, Tomáš; Šefrna, Luděk; Mihaljevič, Martin

    2014-09-01

    The Distichia peat core obtained in the Carhuasanta valley near Nevado Mismi, Cordillera Chila, provides information on climatic and environmental conditions over the last ˜4300 years. The relative changes in the stable carbon isotope composition of plant remains preserved in the core reflect major temperature fluctuations in the Western Cordillera of the southern Peruvian Andes. These temperature variations can be additionally linked with the changes in precipitation patterns by analysing C% and C/N ratio in the core. Relatively warm and moist conditions prevailed from 4280 to 3040 cal. yrs BP (BC 2330-1090) with a short colder dry episode around 3850 cal. yrs BP (BC 1900). The most prominent climate changes recorded in the peat occurred between 3040 and 2750 cal. yrs BP (BC 1090-800) when the initial warming turned to a rapid cooling to temperatures at least 2 °C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP (BC 830) when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes matching the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years when an extended warm and relatively humid period occurred between 640 and 155 cal. yrs BP (AD 1310-1795) followed by predominantly colder and drier conditions. The established δ13C peat record represents the first continuous proxy for the temperature in the southern Peruvian Andes dated by the AMS 14C. Distichia peat is wide spread in the Andes and the proposed approach can be applied elsewhere in high altitudes, where no other traditional climate proxies are available.

  19. Apatite fission-track dating of erosion in the eastern Andes, Bolivia

    International Nuclear Information System (INIS)

    Crough, S.T.

    1983-01-01

    Three samples from a Triassic-age batholith in the eastern Andes northeast of La Paz, Bolivia yield apatitic fission-track ages of 11-13 Ma. Interpreting these young ages as due to uplift and erosion requires approximately 2.5-5.0 km of erosion in the past 12 Ma, an amount which is consistent with the known geology and which is typical of many active mountain ranges. (orig.)

  20. Culture and landslide risk in the Central Andes of Bolivia and Peru

    OpenAIRE

    Nicholas Roberts

    2009-01-01

    Culture and its heritage play a major role in determining landslide risk in the Central Andes. Examples of some of these many possible influences are provided from natural and social science literature and from the author’s recent work in Bolivia. Landslide risk appears to have generally increased throughout the last millennium, due largely to anthropogenic modification of hazard, exposure, vulnerability and coping capacity. These changes result from both local and distant pressures and from ...

  1. GIS as a tool in participatory natural resource management: Examples from the Peruvian Andes

    OpenAIRE

    Bussink, C.

    2003-01-01

    Metadata only record Geographic Information Systems (GIS) are often seen as incompatible with participatory processes. However, since the late 1990s, attempts have been made in numerous projects around the world to define 'best practices' for improved natural resource management projects that integrate participation and accurate spatial information, using GIS (for example, see www.iapad.org/participatory_gis.htm). This article describes a project in the Peruvian Andes where spatial informa...

  2. The System Nobody Sees: Irrigated Wetland Management and Alpaca Herding in the Peruvian Andes

    OpenAIRE

    Verzijl, A.; Guerrero Quispe, S.

    2013-01-01

    Increasingly, attention in regional, national, and international water governance arenas has focused on high-altitude wetlands. However, existing local water management practices in these wetlands are often overlooked. This article looks at the irrigation activities of alpaca herders in the community of Ccarhuancho in the Central Andes of Peru. For more than two centuries, they have been constructing small-scale irrigation canals to maintain and expand the local wetlands, called bofedales. Th...

  3. On the extension of the analytic nodal diffusion solver ANDES to sodium fast reactors

    International Nuclear Information System (INIS)

    Ochoa, R.; Herrero, J.J.; Garcia-Herranz, N.

    2011-01-01

    Within the framework of the Collaborative Project for a European Sodium Fast Reactor, the reactor physics group at UPM is working on the extension of its in-house multi-scale advanced deterministic code COBAYA3 to Sodium Fast Reactors (SFR). COBAYA3 is a 3D multigroup neutron kinetics diffusion code that can be used either as a pin-by-pin code or as a stand-alone nodal code by using the analytic nodal diffusion solver ANDES. It is coupled with thermal-hydraulics codes such as COBRA-TF and FLICA, allowing transient analysis of LWR at both fine-mesh and coarse-mesh scales. In order to enable also 3D pin-by-pin and nodal coupled NK-TH simulations of SFR, different developments are in progress. This paper presents the first steps towards the application of COBAYA3 to this type of reactors. ANDES solver, already extended to triangular-Z geometry, has been applied to fast reactor steady-state calculations. The required cross section libraries were generated with ERANOS code for several configurations. Here some of the limitations encountered when attempting to apply the Analytical Coarse Mesh Finite Difference (ACMFD) method - implemented inside ANDES - to fast reactor calculations are discussed and the sensitivity of the method to the energy-group structure is studied. In order to reinforce some of the conclusions obtained two calculations are presented. The first one involves a 3D mini-core model in 33 groups, where the ANDES solver presents several issues. And secondly, a benchmark from the NEA for a small 3D FBR in hexagonal-Z geometry in 4 energy groups is used to verify the good convergence of the code in a few-energy-group structure. (author)

  4. Glacier loss and hydro-social risks in the Peruvian Andes

    Science.gov (United States)

    Mark, Bryan G.; French, Adam; Baraer, Michel; Carey, Mark; Bury, Jeffrey; Young, Kenneth R.; Polk, Molly H.; Wigmore, Oliver; Lagos, Pablo; Crumley, Ryan; McKenzie, Jeffrey M.; Lautz, Laura

    2017-12-01

    Accelerating glacier recession in tropical highlands and in the Peruvian Andes specifically is a manifestation of global climate change that is influencing the hydrologic cycle and impacting water resources across a range of socio-environmental systems. Despite predictions regarding the negative effects of long-term glacier decline on water availability, many uncertainties remain regarding the timing and variability of hydrologic changes and their impacts. To improve context-specific understandings of the effects of climate change and glacial melt on water resources in the tropical Andes, this article synthesizes results from long-term transdisciplinary research with new findings from two glacierized Peruvian watersheds to develop and apply a multi-level conceptual framework focused on the coupled biophysical and social determinants of water access and hydro-social risks in these settings. The framework identifies several interacting variables-hydrologic transformation, land cover change, perceptions of water availability, water use and infrastructure in local and regional economies, and water rights and governance-to broadly assess how glacier change is embedded with social risks and vulnerability across diverse water uses and sectors. The primary focus is on the Santa River watershed draining the Cordillera Blanca to the Pacific. Additional analysis of hydrologic change and water access in the geographically distinct Shullcas River watershed draining the Huaytapallana massif towards the city of Huancayo further illuminates the heterogeneous character of hydrologic risk and vulnerability in the Andes.

  5. Calculated WIMP signals at the ANDES laboratory: comparison with northern and southern located dark matter detectors

    Science.gov (United States)

    Civitarese, O.; Fushimi, K. J.; Mosquera, M. E.

    2016-12-01

    Weakly interacting massive particles (WIMPs) are possible components of the Universe’s dark matter (DM). The detection of WIMPs is signaled by the recoil of the atomic nuclei which form a detector. CoGeNT at the Soudan Underground Laboratory (SUL) and DAMA at the Laboratori Nazionali del Gran Sasso (LNGS) have reported data on annual modulation of signals attributed to WIMPs. Both experiments are located in laboratories in the Northern Hemisphere. DM detectors are planned to operate (or already operate) in laboratories in the Southern Hemisphere, including SABRE at Stawell Underground Physics Laboratory (SUPL) in Australia, and DM-ICE in Antarctica. In this work we have analyzed the dependence of diurnal and annual modulation of signals, pertaining to the detection of WIMP, on the coordinates of the laboratory, for experiments which may be performed in the planned new Agua Negra Deep Experimental Site (ANDES) underground facility, to be built in San Juan, Argentina. We made predictions for NaI and Ge-type detectors placed in ANDES, to compare with DAMA, CoGeNT, SABRE and DM-ICE arrays, and found that the diurnal modulation of the signals, at the ANDES site, is amplified at its maximum value, both for NaI (Ge)-type detectors, while the annual modulation remains unaffected by the change in coordinates from north to south.

  6. Calculated WIMP signals at the ANDES laboratory: comparison with northern and southern located dark matter detectors

    International Nuclear Information System (INIS)

    Civitarese, O; Mosquera, M E; Fushimi, K J

    2016-01-01

    Weakly interacting massive particles (WIMPs) are possible components of the Universe’s dark matter (DM). The detection of WIMPs is signaled by the recoil of the atomic nuclei which form a detector. CoGeNT at the Soudan Underground Laboratory (SUL) and DAMA at the Laboratori Nazionali del Gran Sasso (LNGS) have reported data on annual modulation of signals attributed to WIMPs. Both experiments are located in laboratories in the Northern Hemisphere. DM detectors are planned to operate (or already operate) in laboratories in the Southern Hemisphere, including SABRE at Stawell Underground Physics Laboratory (SUPL) in Australia, and DM-ICE in Antarctica. In this work we have analyzed the dependence of diurnal and annual modulation of signals, pertaining to the detection of WIMP, on the coordinates of the laboratory, for experiments which may be performed in the planned new Agua Negra Deep Experimental Site (ANDES) underground facility, to be built in San Juan, Argentina. We made predictions for NaI and Ge-type detectors placed in ANDES, to compare with DAMA, CoGeNT, SABRE and DM-ICE arrays, and found that the diurnal modulation of the signals, at the ANDES site, is amplified at its maximum value, both for NaI (Ge)-type detectors, while the annual modulation remains unaffected by the change in coordinates from north to south. (paper)

  7. Highly differentiated, resting gn-specific memory CD8+ T cells persist years after infection by andes hantavirus.

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    Tobias Manigold

    2010-02-01

    Full Text Available In man, infection with South American Andes virus (ANDV causes hantavirus cardiopulmonary syndrome (HCPS. HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-gamma ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gn-derived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3(+CD8(+ T cells were specific for the single HLA-B*3501-restricted epitope Gn(465-473 years after the acute infection. Remarkably, Gn(465-473-specific cells readily secreted IFN-gamma, granzyme B and TNF-alpha but not IL-2 upon stimulation and showed a 'revertant' CD45RA(+CD27(-CD28(-CCR7(-CD127(- effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T

  8. Facing unprecedented drying of the Central Andes? Precipitation variability over the period AD 1000–2100

    International Nuclear Information System (INIS)

    Neukom, Raphael; Salzmann, Nadine; Huggel, Christian; Rohrer, Mario; Calanca, Pierluigi; Acuña, Delia; Christie, Duncan A; Morales, Mariano S

    2015-01-01

    Projected future trends in water availability are associated with large uncertainties in many regions of the globe. In mountain areas with complex topography, climate models have often limited capabilities to adequately simulate the precipitation variability on small spatial scales. Also, their validation is hampered by typically very low station density. In the Central Andes of South America, a semi-arid high-mountain region with strong seasonality, zonal wind in the upper troposphere is a good proxy for interannual precipitation variability. Here, we combine instrumental measurements, reanalysis and paleoclimate data, and a 57-member ensemble of CMIP5 model simulations to assess changes in Central Andes precipitation over the period AD 1000–2100. This new database allows us to put future projections of precipitation into a previously missing multi-centennial and pre-industrial context. Our results confirm the relationship between regional summer precipitation and 200 hPa zonal wind in the Central Andes, with stronger Westerly winds leading to decreased precipitation. The period of instrumental coverage (1965–2010) is slightly dryer compared to pre-industrial times as represented by control simulations, simulations from the past Millennium, ice core data from Quelccaya ice cap and a tree-ring based precipitation reconstruction. The model ensemble identifies a clear reduction in precipitation already in the early 21st century: the 10 year running mean model uncertainty range (ensemble 16–84% spread) is continuously above the pre-industrial mean after AD 2023 (AD 2028) until the end of the 21st century in the RCP2.6 (RCP8.5) emission scenario. Average precipitation over AD 2071–2100 is outside the range of natural pre-industrial variability in 47 of the 57 model simulations for both emission scenarios. The ensemble median fraction of dry years (defined by the 5th percentile in pre-industrial conditions) is projected to increase by a factor of 4 until 2071

  9. A Million-Year Record of Glaciation in the Tropical Andes

    Science.gov (United States)

    Smith, J. A.; Seltzer, G. O.; Rodbell, D. T.; Farber, D. L.; Finkel, R. C.

    2004-12-01

    We present a longterm record of glaciation in the tropical Andes based on cosmogenic dating (10Be) of boulders on moraines. Well-preserved moraines in deglaciated valleys bordering the Junin Plain in central Peru ( ˜11° S, 76° W, 4000 m) were deposited during several glacial cycles extending back more than one million years before present (1 Myr BP). The presence of boulders with zero-erosion 10Be exposure ages >1 Myr constrains boulder erosion rates to relatively low values. For boulders at high altitudes, however, even low boulder erosion rates (0.3 to 0.5 m/Myr) make calculated old exposure ages markedly older [e.g., ˜20% older for a zero-erosion age of 400,000 10Be years (400 10Be kyr)]. Exposure ages recalculated with boulder erosion rates of 0.3 m/Myr straddle interglacial marine isotope stage (MIS) 11 ( ˜430-390 kyr BP), fall within glacial MIS 12 ( ˜480-430 kyr BP), but skip over glacial MIS 16 ( ˜670-630 kyr BP), perhaps the largest ice volume of the past 2 Myr. Increasing the erosion rate used in the calculations to 0.5 m/Myr moves ages into both MIS 11 and MIS 16. If we assume that the older Andean glaciations were indeed synchronous with global ice volume, our data suggest that boulder preservation cannot be treated as a simple linear process. Conversely, the data may be suggesting correctly that glaciation of the tropical Andes was not synchronous with the global glaciations as inferred from the marine isotope record. Our chronology for the last glacial maximum (LGM) in the region supports the idea of asynchrony between the global ice volume record and the terrestrial record of glaciation in the tropical Andes. The LGM in the Junin region of Peru and in the Cordillera Real of Bolivia (16° S 68° W) occurred ˜34 to 22 10Be kyr BP and was less extensive than older glaciations. Asynchrony between the LGM in the Northern Hemisphere ( ˜21 kyr BP) and the tropical Andes suggests that previous glaciations in the tropical Andes may have been

  10. Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the Southern Andes

    Science.gov (United States)

    Futa, K.; Stern, C.R.

    1988-01-01

    Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46??S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54??S) range for 87Sr 86Sr from 0.70280 to 0.70591 and for 143Nd 144Nd from 0.51314 to 0.51255. The ranges are significantly greater than previously reported from the southern Andes but are different from the isotopic compositions of volcanoes in the central and northern Andes. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have 87Sr 86Sr, 143Nd 144Nd, La Yb, Ba La, and Hf Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35??S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33?? and 34??S, basaltic andesites and andesites have higher 87Sr 86Sr, Rb Cs, and Hf Lu, and lower 143Nd 144Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54??S) has Sr and Nd isotopic compositions and K Rb and Ba La similar to MORB. The high La Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO2, K2O, Rb, Ba, Ba La, and 87Sr 86Sr and decrease in MgO, Sr, K Rb, Rb Cs, and 143Nd 144Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra

  11. Chikungunya virus

    Science.gov (United States)

    Chikungunya virus infection; Chikungunya ... Where Chikungunya is Found Before 2013, the virus was found in Africa, Asia, Europe, and the Indian and Pacific oceans. In late 2013, outbreaks occurred for the first time in the ...

  12. Zika Virus

    Science.gov (United States)

    ... through blood transfusions. There have been outbreaks of Zika virus in the United States, Africa, Southeast Asia, the ... not travel to areas where there is a Zika virus outbreak. If you do decide to travel, first ...

  13. Zika Virus

    Science.gov (United States)

    ... Funding CDC Activities For Healthcare Providers Clinical Evaluation & Disease Sexual Transmission HIV Infection & Zika Virus Testing for Zika Test Specimens – At Time of Birth Diagnostic Tests Understanding Zika Virus Test Results ...

  14. Developing services for climate impact and adaptation baseline information and methodologies for the Andes

    Science.gov (United States)

    Huggel, C.

    2012-04-01

    Impacts of climate change are observed and projected across a range of ecosystems and economic sectors, and mountain regions thereby rank among the hotspots of climate change. The Andes are considered particularly vulnerable to climate change, not only due to fragile ecosystems but also due to the high vulnerability of the population. Natural resources such as water systems play a critical role and are observed and projected to be seriously affected. Adaptation to climate change impacts is therefore crucial to contain the negative effects on the population. Adaptation projects require information on the climate and affected socio-environmental systems. There is, however, generally a lack of methodological guidelines how to generate the necessary scientific information and how to communicate to implementing governmental and non-governmental institutions. This is particularly important in view of the international funds for adaptation such as the Green Climate Fund established and set into process at the UNFCCC Conferences of the Parties in Cancun 2010 and Durban 2011. To facilitate this process international and regional organizations (World Bank and Andean Community) and a consortium of research institutions have joined forces to develop and define comprehensive methodologies for baseline and climate change impact assessments for the Andes, with an application potential to other mountain regions (AndesPlus project). Considered are the climatological baseline of a region, and the assessment of trends based on ground meteorological stations, reanalysis data, and satellite information. A challenge is the scarcity of climate information in the Andes, and the complex climatology of the mountain terrain. A climate data platform has been developed for the southern Peruvian Andes and is a key element for climate data service and exchange. Water resources are among the key livelihood components for the Andean population, and local and national economy, in particular for

  15. Rapid Diversification and Time Explain Amphibian Richness at Different Scales in the Tropical Andes, Earth's Most Biodiverse Hotspot.

    Science.gov (United States)

    Hutter, Carl R; Lambert, Shea M; Wiens, John J

    2017-12-01

    The Tropical Andes make up Earth's most species-rich biodiversity hotspot for both animals and plants. Nevertheless, the ecological and evolutionary processes underlying this extraordinary richness remain uncertain. Here, we examine the processes that generate high richness in the Tropical Andes relative to other regions in South America and across different elevations within the Andes, using frogs as a model system. We combine distributional data, a newly generated time-calibrated phylogeny for 2,318 frog species, and phylogenetic comparative methods to test the relative importance of diversification rates and colonization times for explaining Andean diversity at different scales. At larger scales (among regions and families), we find that faster diversification rates in Andean clades most likely explain high Andean richness. In contrast, at smaller temporal and spatial scales (within family-level clades within the Andes), diversification rates rarely explain richness patterns. Instead, we show that colonization times are important for shaping elevational richness patterns within the Andes, with more species found in habitats colonized earlier. We suggest that these scale-dependent patterns might apply to many other richness gradients. Recognition of this scale dependence may help to reconcile conflicting results among studies of richness patterns across habitats, regions, and organisms.

  16. Seismicity, fault plane solutions, depth of faulting, and active tectonics of the Andes of Peru, Ecuador, and southern Colombia

    Science.gov (United States)

    Suarez, G.; Molnar, P.; Burchfiel, B. C.

    1983-01-01

    The long-period P waveforms observed for 17 earthquakes in the Peruvian Andes during 1963-1976 are compared with synthetic waveforms to obtain fault-plane solutions and focal depths. The morphological units of the Peruvian Andes are characterized: coastal plains, Cordillera Occidental, altiplano and central high plateau, Cordillera Oriental, and sub-Andes. The data base and analysis methodology are discussed, and the results are presented in tables, diagrams, graphs, maps, and photographs illustrating typical formations. Most of the earthquakes are shown to occur in the transition zone from the sub-Andes to the Cordillera Oriental under formations of about 1 km elevation at focal depths of 10-38 km. It is suggested that the sub-Andean earthquakes reflect hinterland deformation of a detached fold and thrust belt, perhaps like that which occurred in parts of the Canadian Rockies. From the total crustal shortening evident in Andean morphology and the shortening rate of the recent earthquakes it is estimated that the topography and crustal root of the Andes have been formed during the last 90-135 Myr.

  17. Subvolcanic contact metasomatism at El Laco Volcanic Complex, Central Andes Metasomatismo de contacto subvolcánico en el Complejo Volcánico El Laco, Andes centrales

    Directory of Open Access Journals (Sweden)

    José A Naranjo

    2010-01-01

    Full Text Available Studies of drill cores from the Pasos Blancos area at El Laco in the central Andes, northern Chile, give evidence of an intense and extensive subvolcanic contact-metasomatic process. This process resulted from shallow-level emplacement of very volatile-rich iron-oxide magma, with discharge of volatiles that resulted in extensive fracturing of overlying volcanic rocks. The brecciated rocks were altered (mainly extensive scapolitization and formation of pyroxene by hot magmatic fluids emitted from the cooling intrusion , and accompanied by magnetite deposition. With time and decreasing temperature, the metasomatic fluids evolved to fluids of hydrothermal character, and a final recent geothermal event took place that deposited superficial gypsum over a large part of the El Laco Volcanic Complex.Estudios realizados en testigos de sondajes en el area de Pasos Blancos en El Laco, en los Andes Centrales del norte de Chile, dan evidencias de un intenso y extenso proceso subvolcánico de metasomatismo de contacto. Este proceso es el resultado de un emplazamiento a poca profundidad de un magma de óxido de fierro muy rico en volátiles y cuya descarga de gases produjo un intenso fracturamiento de las rocas sobrepuestas. Las rocas brechizadas fueron alteradas (principalmente una extensa escapolitización y formación de piroxeno, junto con la depositación de magnetita, por los fluidos magmáticos calientes emitidos por la intrusión durante su enfriamiento. Los fluidos metasomáticos evolucionaron en el tiempo y con la disminución de temperatura, a fluidos de carácter hidrotermal y finalmente tuvo lugar un evento geotérmico reciente, el cual depositó yeso superficial en gran parte del Complejo Volcánico El Laco.

  18. Constraints on deformation of the Southern Andes since the Cretaceous from anisotropy of magnetic susceptibility

    Science.gov (United States)

    Maffione, Marco; Hernandez-Moreno, Catalina; Ghiglione, Matias C.; Speranza, Fabio; van Hinsbergen, Douwe J. J.; Lodolo, Emanuele

    2015-12-01

    The southernmost segment of the Andean Cordillera underwent a complex deformation history characterized by alternation of contractional, extensional, and strike-slip tectonics. Key elements of southern Andean deformation that remain poorly constrained, include the origin of the orogenic bend known as the Patagonian Orocline (here renamed as Patagonian Arc), and the exhumation mechanism of an upper amphibolite facies metamorphic complex currently exposed in Cordillera Darwin. Here, we present results of anisotropy of magnetic susceptibility (AMS) from 22 sites in Upper Cretaceous to upper Eocene sedimentary rocks within the internal structural domain of the Magallanes fold-and-thrust belt in Tierra del Fuego (Argentina). AMS parameters from most sites reveal a weak tectonic overprint of the original magnetic fabric, which was likely acquired upon layer-parallel shortening soon after sedimentation. Magnetic lineation from 17 sites is interpreted to have formed during compressive tectonic phases associated to a continuous N-S contraction. Our data, combined with the existing AMS database from adjacent areas, show that the Early Cretaceous-late Oligocene tectonic phases in the Southern Andes yielded continuous contraction, variable from E-W in the Patagonian Andes to N-S in the Fuegian Andes, which defined a radial strain field. A direct implication is that the exhumation of the Cordillera Darwin metamorphic complex occurred under compressive, rather than extensional or strike-slip tectonics, as alternatively proposed. If we agree with recent works considering the curved Magallanes fold-and-thrust belt as a primary arc (i.e., no relative vertical-axis rotation of the limbs occurs during its formation), then other mechanisms different from oroclinal bending should be invoked to explain the documented radial strain field. We tentatively propose a kinematic model in which reactivation of variably oriented Jurassic faults at the South American continental margin controlled

  19. Population dynamics of the rat Microryzomys minutus (Rodentia: Muridae in the Venezuelan Andes

    Directory of Open Access Journals (Sweden)

    Daniel R Cabello

    2006-06-01

    Full Text Available The population dynamics of the small forest rice rat Microryzomys minutus, a murid rodent that occurs in the high altitudes of the northern and central Andes, was studied in disturbed and primary environments in a cloud forest of the Venezuelan Andes (Juan Pablo Peñaloza National Park, 8º11’N, 71º49’W. We collected 121 animals (66♀♀ and 55♂♂ between 1995 and 1998, using pitfall traps with formalin. Adult males were heavier than adult females. Relative abundance was much greater in the disturbed environments (over 10 individuals in some periods than in the primary cloud forest: 4-8 individuals. In the disturbed environments, the rats were extremely abundant in the first sampling period, and less frequent afterwards. In the cropland, abundance showed some fluctuations during the study and displayed two small abundance peaks in March-June 1997 and 1998. In the mined area, the rats had irregular fluctuations until March-June 1997 and were not recorded in July-October 1997. The occurrence of this rat in both disturbed and natural habitats confirms the wide ecological tolerance of this species. Rev. Biol. Trop. 54(2: 651-. Epub 2006 Jun 01.Se analizó la dinámica poblacional de las pequeñas ratas silvestres del arroz Microryzomys minutus en ambientes alterados y primarios, en un bosque nublado de los Andes venezolanos. El estudio fue basado en 121 animales (66♀♀ y 55♂♂ recolectados entre 1995 y 1998, usando trampas que contenían formalina. Esta especie está presente en ambos hábitats lo que confirma su amplia tolerancia ecológica. La abundancia poblacional fue mayor en ambientes alterados que en los no alterados. M. minutus presenta dimorfismo sexual en el peso: los machos son más pesados que las hembras.

  20. Setting practical conservation priorities for birds in the Western Andes of Colombia.

    Science.gov (United States)

    Ocampo-Peñuela, Natalia; Pimm, Stuart L

    2014-10-01

    We aspired to set conservation priorities in ways that lead to direct conservation actions. Very large-scale strategic mapping leads to familiar conservation priorities exemplified by biodiversity hotspots. In contrast, tactical conservation actions unfold on much smaller geographical extents and they need to reflect the habitat loss and fragmentation that have sharply restricted where species now live. Our aspirations for direct, practical actions were demanding. First, we identified the global, strategic conservation priorities and then downscaled to practical local actions within the selected priorities. In doing this, we recognized the limitations of incomplete information. We started such a process in Colombia and used the results presented here to implement reforestation of degraded land to prevent the isolation of a large area of cloud forest. We used existing range maps of 171 bird species to identify priority conservation areas that would conserve the greatest number of species at risk in Colombia. By at risk species, we mean those that are endemic and have small ranges. The Western Andes had the highest concentrations of such species-100 in total-but the lowest densities of national parks. We then adjusted the priorities for this region by refining these species ranges by selecting only areas of suitable elevation and remaining habitat. The estimated ranges of these species shrank by 18-100% after accounting for habitat and suitable elevation. Setting conservation priorities on the basis of currently available range maps excluded priority areas in the Western Andes and, by extension, likely elsewhere and for other taxa. By incorporating detailed maps of remaining natural habitats, we made practical recommendations for conservation actions. One recommendation was to restore forest connections to a patch of cloud forest about to become isolated from the main Andes. © 2014 Society for Conservation Biology.

  1. Geografía, café y prosperidad en los andes occidentales de Colombia

    Directory of Open Access Journals (Sweden)

    Juan Barón

    2011-07-01

    Full Text Available Compuesta por los departamentos de Antioquia, Caldas, Quindío, Risaralda y Valle del Cauca, los Andes Occidentales ha sido por mucho años una de las regiones más prósperas de Colombia. Esta prosperidad se ha traducido en condiciones de vida e infraestructura superiores a las del resto del país. El éxito y bienestar que presentan hoy en día los Andes Occidentales están estrechamente ligados a la concentración de la producción de café, que se dio allí durante gran parte del siglo XX. El arraigo del café en la región no sólo se dio debido a que la geografía ofrecía las condiciones ideales para el cultivo, sino también a las instituciones cafeteras creadas para organizar la industria del café. A pesar de esta prosperidad, el constante descenso del precio internacional del café después del rompimiento del pacto de cuotas de producción en 1989, sumado al estancamiento de la industria manufacturera en algunos departamentos de la región, han afectado las economías departamentales menos diversificadas. Es así como la región de los Andes Occidentales Colombianos presenta las tasas de desempleo más altas del país, tasas que se han visto afectadas aún más con la crisis financiera internacional a través del menor flujo de remesas que los trabajadores oriundos de la región, y residentes en el exterior envían a sus familias.

  2. Influence of spatial resolution on precipitation simulations for the central Andes Mountains

    Science.gov (United States)

    Trachte, Katja; Bendix, Jörg

    2013-04-01

    The climate of South America is highly influenced by the north-south oriented Andes Mountains. Their complex structure causes modifications of large-scale atmospheric circulations resulting in various mesoscale phenomena as well as a high variability in the local conditions. Due to their height and length the terrain generates distinctly climate conditions between the western and the eastern slopes. While in the tropical regions along the western flanks the conditions are cold and arid, the eastern slopes are dominated by warm-moist and rainy air coming from the Amazon basin. Below 35° S the situation reverses with rather semiarid conditions in the eastern part and temperate rainy climate along southern Chile. Generally, global circulation models (GCMs) describe the state of the global climate and its changes, but are disabled to capture regional or even local features due to their coarse resolution. This is particularly true in heterogeneous regions such as the Andes Mountains, where local driving features, e. g. local circulation systems, highly varies on small scales and thus, lead to a high variability of rainfall distributions. An appropriate technique to overcome this problem and to gain regional and local scale rainfall information is the dynamical downscaling of the global data using a regional climate model (RCM). The poster presents results of the evaluation of the performance of the Weather Research and Forecasting (WRF) model over South America with special focus on the central Andes Mountains of Ecuador. A sensitivity study regarding the cumulus parametrization, microphysics, boundary layer processes and the radiation budget is conducted. With 17 simulations consisting of 16 parametrization scheme combinations and 1 default run a suitable model set-up for climate research in this region is supposed to be evaluated. The simulations were conducted in a two-way nested mode i) to examine the best physics scheme combination for the target and ii) to

  3. Analysis of La Dehesa paleo-landslide. Central Pre-Andes of Argentina

    Science.gov (United States)

    Tapia Baldis, Carla; Rothis, Luis Martín; Perucca, Laura; Esper Angillieri, María; Vargas, Horacio; Ponce, David; Allis, Carlos

    2018-04-01

    The main objective of this paper is to consider the influence of Quaternary faults as likely triggering factor for rockslides occurrence in the Central Pre-Andes, a region with intense shallow seismic activity. A rockslide deposit was selected as study case, placed in the western flank of La Dehesa and Talacasto (DT) range (31°3‧37″ S and 68°46‧ 8″ W). Applied methodology includes the characterization of main discontinuities, reconstruction of the topography using a high-resolution digital elevation model, safety factor calculation along the sliding surface and, Newmark displacements estimation for three different hypothetical seismic scenarios, recreated from existing neotectonic local information. Equilibrium-limit method's results confirm that study case, La Dehesa rockslide (LDR), had a stable and safe slope's configuration under static conditions. However, a seismic horizontal coefficient between 0.2 and 0.3 decreases safety factor below the safety threshold. Newmark's displacements for different seismic reconstructed scenarios varies between 4.1 and 15.9 cm, values that agreed with a coherent failure process, likely triggered by Pleistocene to Holocene seismogenic sources in Central Pre-Andes. LDR trigger could be assigned mainly to an earthquake related to La Dehesa Quaternary fault (LDF) activity; however, similar movements produced by neighboring faults should not be discarded. LDR triggering related to climatic conditions is despised. Finally, the methodology presented in this work is easy to reproduce and may be applied to other rockslides located in the mountainous areas of the Central Pre-Andes of Argentina.

  4. Mio-Pliocene aridity in the south-central Andes associated with Southern Hemisphere cold periods.

    Science.gov (United States)

    Amidon, William H; Fisher, G Burch; Burbank, Douglas W; Ciccioli, Patricia L; Alonso, Ricardo N; Gorin, Andrew L; Silverhart, Perri H; Kylander-Clark, Andrew R C; Christoffersen, Michael S

    2017-06-20

    Although Earth's climate history is best known through marine records, the corresponding continental climatic conditions drive the evolution of terrestrial life. Continental conditions during the latest Miocene are of particular interest because global faunal turnover is roughly synchronous with a period of global glaciation from ∼6.2-5.5 Ma and with the Messinian Salinity Crisis from ∼6.0-5.3 Ma. Despite the climatic and ecological significance of this period, the continental climatic conditions associated with it remain unclear. We address this question using erosion rates of ancient watersheds to constrain Mio-Pliocene climatic conditions in the south-central Andes near 30° S. Our results show two slowdowns in erosion rate, one from ∼6.1-5.2 Ma and another from 3.6 to 3.3 Ma, which we attribute to periods of continental aridity. This view is supported by synchrony with other regional proxies for aridity and with the timing of glacial ‟cold" periods as recorded by marine proxies, such as the M2 isotope excursion. We thus conclude that aridity in the south-central Andes is associated with cold periods at high southern latitudes, perhaps due to a northward migration of the Southern Hemisphere westerlies, which disrupted the South American Low Level Jet that delivers moisture to southeastern South America. Colder glacial periods, and possibly associated reductions in atmospheric CO 2 , thus seem to be an important driver of Mio-Pliocene ecological transitions in the central Andes. Finally, this study demonstrates that paleo-erosion rates can be a powerful proxy for ancient continental climates that lie beyond the reach of most lacustrine and glacial archives.

  5. Intraseasonal variability of organized convective systems in the Central Andes: Relationship to Regional Dynamical Features

    Science.gov (United States)

    Mohr, K. I.; Slayback, D. A.; Nicholls, S.; Yager, K.

    2013-12-01

    The Andes extend from the west coast of Colombia (10N) to the southern tip of Chile (53S). In southern Peru and Bolivia, the Central Andes is split into separate eastern and western cordilleras, with a high plateau (≥ 3000 m), the Altiplano, between them. Because 90% of the Earth's tropical mountain glaciers are located in the Central Andes, our study focuses on this region, defining its zonal extent as 7S-21S and the meridional extent as the terrain 1000 m and greater. Although intense convection occurs during the wet season in the Altiplano, it is not included in the lists of regions with frequent or the most intense convection. The scarcity of in-situ observations with sufficient density and temporal resolution to resolve individual storms or even mesoscale-organized cloud systems and documented biases in microwave-based rainfall products in poorly gauged mountainous regions have impeded the development of an extensive literature on convection and convective systems in this region. With the tropical glaciers receding at unprecedented rates, leaving seasonal precipitation as an increasingly important input to the water balance in alpine valley ecosystems and streams, understanding the nature and characteristics of the seasonal precipitation becomes increasingly important for the rural economies in this region. Previous work in analyzing precipitation in the Central Andes has emphasized interannual variability with respect to ENSO, this is the first study to focus on shorter scale variability with respect to organized convection. The present study took advantage of the University of Utah's Precipitation Features database compiled from 14 years of TRMM observations (1998-2012), supplemented by field observations of rainfall and streamflow, historical gauge data, and long-term WRF-simulations, to analyze the intraseasonal variability of precipitating systems and their relationship regional dynamical features such as the Bolivian High. Through time series and

  6. Prediction of extreme floods in the Central Andes by means of Complex Networks

    Science.gov (United States)

    Boers, Niklas; Bookhagen, Bodo; Barbosa, Henrique; Marwan, Norbert; Kurths, Jürgen; Marengo, Jose

    2014-05-01

    Based on a non-linear synchronisation measure and complex network theory, we present a novel framework for the prediction of extreme events of spatially embedded, interrelated time series. This method is general in the sense that it can be applied to any type of spatially sampled time series with significant interrelations, ranging from climate observables to biological or stock market data. In this presentation, we apply our method to extreme rainfall in South America and show how this leads to the prediction of more than 60% (90% during El Niño conditions) of extreme rainfall events in the eastern Central Andes of Bolivia and northern Argentina, with only 1% false alarms. From paleoclimatic to decadal time scales, the Central Andes continue to be subject to pronounced changes in climatic conditions. In particular, our and past work shows that frequency as well as magnitudes of extreme rainfall events have increased significantly during past decades, calling for a better understanding of the involved climatic mechanisms. Due to their large spatial extend and occurrence at high elevations, these extreme events often lead to severe floods and landslides with disastrous socioeconomic impacts. They regularly affect tens of thousands of people and produce estimated costs of the order of several hundred million USD. Alongside with the societal value of predicting natural hazards, our study provides insights into the responsible climatic features and suggests interactions between Rossby waves in polar regions and large scale (sub-)tropical moisture transport as a driver of subseasonal variability of the South American monsoon system. Predictable extreme events result from the propagation of extreme rainfall from the region of Buenos Aires towards the Central Andes given characteristic atmospheric conditions. Our results indicate that the role of frontal systems originating from Rossby waves in polar latitudes is much more dominant for controlling extreme rainfall in

  7. Culture and landslide risk in the Central Andes of Bolivia and Peru

    Directory of Open Access Journals (Sweden)

    Nicholas Roberts

    2009-06-01

    Full Text Available Culture and its heritage play a major role in determining landslide risk in the Central Andes. Examples of some of these many possible influences are provided from natural and social science literature and from the author’s recent work in Bolivia. Landslide risk appears to have generally increased throughout the last millennium, due largely to anthropogenic modification of hazard, exposure, vulnerability and coping capacity. These changes result from both local and distant pressures and from contemporaneous and pervious cultural factors. Consequently, holistic examination of landslide risk necessitates consideration of culture and its heritage.

  8. [Fertility and reproductive behavior in Peru: Andes mountains and the Amazon basin].

    Science.gov (United States)

    Fort, A L

    1992-01-01

    "The article attempts to discuss the historical and contemporary situations of [fertility among] populations residing in the two least studied areas of Peru: the Andes mountains and the Amazon basin. The study starts with a review of the 'demographic catastrophe' that the Spanish presence meant to the people of these areas.... The harmful effects of the 'rubber boom' and, more recently, of the 'oil boom', periods are also reviewed." Fertility trends in the two areas are analyzed, with a focus on marriage, breast-feeding, and contraceptive use. (SUMMARY IN ENG) excerpt

  9. Trophic polymorphism, habitat and diet segregation in Percichthys trucha (Pisces : Percichthyidae) in the Andes

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Walde, S.J.; Cussac, V.E.

    1998-01-01

    Divergent natural selection affecting specific trait combinations that lead to greater efficiency in resource exploitation is believed to be a major mechanism leading to trophic polymorphism and adaptive radiation. We present evidence of trophic polymorphism involving two benthic morphs within...... Percichthys trucha, a fish endemic to temperate South America. In a series of lakes located in the southern Andes, we found two morphs of P. trucha that could be distinguished on the basis of gill raker length and five other morphological measures, most of which are likely associated with the use of food...

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

    Science.gov (United States)

    Drewes, H.

    1978-01-01

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

  11. Tectonic geomorphology of the Andes with SIR-A and SIR-B

    Science.gov (United States)

    Bloom, Arthur L.; Fielding, Eric J.

    1986-01-01

    Data takes from SIR-A and SIR-B (Shuttle Imaging Radar) crossed all of the principal geomorphic provinces of the central Andes between 17 and 34 S latitude. In conjunction with Thematic Mapping images and photographs from hand-held cameras as well as from the Large Format Camera that was flown with SIR-B, the radar images give an excellent sampling of Andean geomorphology. In particular, the radar images show new details of volcanic rocks and landforms of late Cenozoic age in the Puna, and the exhumed surfaces of tilted blocks of Precambrian crystalline basement in the Sierras Pampeanas.

  12. SRTM Perspective of Colored Height and Shaded Relief Laguna Mellquina, Andes Mountains, Argentina

    Science.gov (United States)

    2001-01-01

    This depiction of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM)view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters (2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.Three visualization methods were combined to produce this image: shading, color coding of topographic height and a perspective view. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations. The perspective is toward the west, 20 degrees off horizontal with 2X vertical exaggeration. The back (west) edge of the data set forms a false skyline within the Andes Range.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved

  13. Amalgamation and small-scale gold mining in the ancient Andes

    OpenAIRE

    Brooks, William E.; Schwörbel, Gabriela; Castillo, Luis Enrique

    2013-01-01

    In 1532, the volume of gold provided by Atahualpa, the Inka king, as ransom for his release from the Spanish was hard evidence for the efficient small-scale gold mining that took place before European contact and the number of gold occurrences in the Andes. At Huancavelica, Perú, mercury occurs as a native metal and as cinnabar [HgS], which was used for pigments, funeral preparations, and retorted to obtain mercury. Using Inductively Coupled Plasma analysis (ICP), an average of 15 ppm (parts...

  14. Ausentismo laboral de causa médica en el Instituto Autónomo Hospital Universitario de Los Andes.

    OpenAIRE

    Parada de Denis, María Eugenia; Rivas Padilla, Fernando; Moreno Barrios, Reyla; Rincón, Eglis; Mejía, Zurayma; Mora, Dania Margarita

    2006-01-01

    Editorial. ¡Ya tenemos símbolo, ícono o logotipo!. Now we have symbol, icono or logo!. Salinas, Pedro José Accidentes domésticos en ancianos. Municipio Libertador. Mérida. 1993-1996. Domestics accidents in elderly people. Libertador County of Mérida State. 1993-1996. Salinas, Pedro José Rojas Márquez, Reina Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes. Stress and symptoms in health staff of the Hospital Universitario de Los Andes. Méri...

  15. Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes.

    OpenAIRE

    Manzanilla, María D.; Molina de González Méndez, Tivizay; Caltagirone, Raimondo; Vera , Mariflor; Torres, Adrián R.

    2007-01-01

    Editorial. ¡Ya tenemos símbolo, ícono o logotipo!. Now we have symbol, icono or logo!. Salinas, Pedro José Accidentes domésticos en ancianos. Municipio Libertador. Mérida. 1993-1996. Domestics accidents in elderly people. Libertador County of Mérida State. 1993-1996. Salinas, Pedro José Rojas Márquez, Reina Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes. Stress and symptoms in health staff of the Hospital Universitario de Los Andes. Méri...

  16. Regionalisation of Hydrological Indices to Assess Land-Use Change Impacts in the Tropical Andes

    Science.gov (United States)

    Buytaert, W.; Ochoa Tocachi, B. F.

    2014-12-01

    Andean ecosystems are major water sources for cities and communities located in the Tropical Andes; however, there is a considerable lack of knowledge about their hydrology. Two problems are especially important: (i) the lack of monitoring to assess the impacts of historical land-use and cover change and degradation (LUCCD) at catchment scale, and (ii) the high variability in climatic and hydrological conditions that complicate the evaluation of land management practices. This study analyses how a reliable LUCCD impacts assessment can be performed in an environment of high variability combined with data-scarcity and low-quality records. We use data from participatory hydrological monitoring activities in 20 catchments distributed along the tropical Andes. A set of 46 hydrological indices is calculated and regionalized by relating them to 42 physical catchment properties. Principal Component Analysis (PCA) is performed to maximise available data while minimising redundancy in the sets of variables. Hydrological model parameters are constrained by estimated indices, and different behavioural predictions are assembled to provide a generalised response on which we assess LUCCD impacts. Results from this methodology show that the attributed effects of LUCCD in pair-wise catchment comparisons may be overstated or hidden by different sources of uncertainty, including measurement inaccuracies and model structural errors. We propose extrapolation and evaluation in ungauged catchments as a way to regionalize LUCCD predictions and to provide statistically significant conclusions in the Andean region. These estimations may deliver reliable knowledge to evaluate the hydrological impact of different watershed management practices.

  17. A new species of Telmatobius (Amphibia, Anura, Telmatobiidae from the Pacific slopes of the Andes, Peru

    Directory of Open Access Journals (Sweden)

    Alessandro Catenazzi

    2015-02-01

    Full Text Available We describe a new species of Telmatobius from the Pacific slopes of the Andes in central Peru. Specimens were collected at 3900 m elevation near Huaytará, Huancavelica, in the upper drainage of the Pisco river. The new species has a snout–vent length of 52.5 ± 1.1 mm (49.3–55.7 mm, n = 6 in adult females, and 48.5 mm in the single adult male. The new species has bright yellow and orange coloration ventrally and is readily distinguished from all other central Peruvian Andean species of Telmatobius but T. intermedius by having vomerine teeth but lacking premaxillary and maxillary teeth, and by its slender body shape and long legs. The new species differs from T. intermedius by its larger size, flatter head, and the absence of cutaneous keratinized spicules (present even in immature females of T. intermedius, and in males by the presence of minute, densely packed nuptial spines on dorsal and medial surfaces of thumbs (large, sparsely packed nuptial spines in T. intermedius. The hyper-arid coastal valleys of Peru generally support low species richness, particularly for groups such as aquatic breeding amphibians. The discovery of a new species in this environment, and along a major highway crossing the Andes, shows that much remains to be done to document amphibian diversity in Peru.

  18. Elevational Shifts in the Topographic Position of Polylepis Forest Stands in the Andes of Southern Peru

    Directory of Open Access Journals (Sweden)

    Johanna M. Toivonen

    2017-12-01

    Full Text Available The patchy distribution of high-Andean treeline forests has provoked discussion about the relative importance of anthropogenic and climatic causes of this pattern, both of which vary with topography. We aimed to understand the topographic controls on the distribution of Polylepis subsericans treeline forests in the Andes of southern Peru, and the changes in these controls along an elevational gradient. We mapped Polylepis forests in the Cordillera Urubamba, Cusco, using high-resolution aerial images and related forest cover to topographic variables extracted from a digital terrain model (30-m resolution. The variables were selected based on their expected biological relevance for tree growth at high elevations. We constructed logistic regression models of forest cover, separately for each of five 100-m elevational belts. To deal with spatial autocorrelation, models were based on randomized 10% subsampling of the data with 1000 repetitions. The results suggest a consistent shift in topographic preference with elevation, with forests at lower elevations showing a preference for topographically protected sites near rivers and forests at higher elevations being increasingly restricted to north-facing and well-drained sites. Our study offers the first indication of the ability of Andean treeline forests to benefit from the topographic heterogeneity of the high-Andes. Providing that dispersal and establishment are possible, local relocation between microsites could help these forests to persist regionally in spite of changing climatic conditions.

  19. Hydrological Modeling of Highly Glacierized Basins (Andes, Alps, and Central Asia

    Directory of Open Access Journals (Sweden)

    Nina Omani

    2017-02-01

    Full Text Available The Soil and Water Assessment Tool (SWAT was used to simulate five glacierized river basins that are global in coverage and vary in climate. The river basins included the Narayani (Nepal, Vakhsh (Central Asia, Rhone (Switzerland, Mendoza (Central Andes, Argentina, and Central Dry Andes (Chile, with a total area of 85,000 km2. A modified SWAT snow algorithm was applied in order to consider spatial variation of associated snowmelt/accumulation by elevation band across each subbasin. In previous studies, melt rates varied as a function of elevation because of an air temperature gradient while the snow parameters were constant throughout the entire basin. A major improvement of the new snow algorithm is the separation of the glaciers from seasonal snow based on their characteristics. Two SWAT snow algorithms were evaluated in simulation of monthly runoff from the glaciered watersheds: (1 the snow parameters are lumped (constant throughout the entire basin and (2 the snow parameters are spatially variable based on elevation bands of a subbasin (modified snow algorithm. Applying the distributed SWAT snow algorithm improved the model performance in simulation of monthly runoff with snow-glacial regime, so that mean RSR decreased to 0.49 from 0.55 and NSE increased to 0.75 from 0.69. Improvement of model performance was negligible in simulations of monthly runoff from the basins with a monsoon runoff regime.

  20. A glacial record of the last termination in the southern tropical Andes

    Science.gov (United States)

    Bromley, G. R.; Schaefer, J. M.; Winckler, G.; Hall, B. L.; Todd, C. E.; Rademaker, K.

    2012-12-01

    The last glacial termination represents the highest-magnitude climate change of the last hundred thousand years. Accurate resolution of events during the termination is vital to our understanding of how - and why - the global climate system transitions from a full glacial to interglacial state, as well as the causes of abrupt climate change during the late-glacial period. Palaeoclimate data from low latitudes, though relatively sparse, are particularly valuable, since the tropical ocean and atmosphere likely play a crucial role in Quaternary climate variability on all timescales. We present a detailed glacier record from the Andes of southern Peru (15°S), resolved with 3He surface-exposure dating and spanning the last glacial maximum and termination. Our dataset reveals that glaciers in this part of the Southern Hemisphere maintained their Late Pleistocene maxima for several millennia and that the onset of the termination may have occurred relatively late. Deglaciation was punctuated by two major advances during the late-glacial period. Following the glacial-interglacial transition, our preliminary chronologic and morphologic data suggest that, in contrast to the Northern Hemisphere, glaciers in the southern tropical Andes have experienced overall shrinkage during the Holocene.

  1. Crustal balance and crustal flux from shortening estimates in the Central Andes

    Science.gov (United States)

    Hindle, David; Kley, Jonas; Oncken, Onno; Sobolev, Stephan

    2005-01-01

    The Central Andes of South America form the second largest high elevation plateau on earth. Extreme elevations have formed on a noncollisional margin with abundant associated arc magmatism. It has long been thought that the crustal thickness necessary to support Andean topography was not accounted for by known crustal shortening alone. We show that this may in part be due to a two-dimensional treatment of the problem. A three-dimensional analysis of crustal shortening and crustal thickness shows that displacement of material towards the axis of the bend in the Central Andes has added a significant volume of crust not accounted for in previous comparisons. We find that present-day crustal thickness between 12°S and 25°S is accounted for (∼-10% to ∼+3%)with the same shortening estimates, and the same assumed initial crustal thickness as had previously led to the conclusion of a ∼25-35% deficit in shortening relative to volume of crustal material. We suggest that the present-day measured crustal thickness distribution may not match that predicted due to shortening, and substantial redistribution of crust may have occurred by both erosion and deposition at the surface and lower crustal flow in regions of the thermally weakened middle and lower crust.

  2. Diversification in the Andes: age and origins of South American Heliotropium lineages (Heliotropiaceae, Boraginales).

    Science.gov (United States)

    Luebert, Federico; Hilger, Hartmut H; Weigend, Maximilian

    2011-10-01

    The uplift of the Andes was a major factor for plant diversification in South America and had significant effects on the climatic patterns at the continental scale. It was crucial for the formation of the arid environments in south-eastern and western South America. However, both the timing of the major stages of the Andean uplift and the onset of aridity in western South America remain controversial. In this paper we examine the hypothesis that the Andean South American groups of Heliotropium originated and diversified in response to Andean orogeny during the late Miocene and a the subsequent development of aridity. To this end, we estimate divergence times and likely biogeographical origins of the major clades in the phylogeny of Heliotropium, using both Bayesian and likelihood methods. Divergence times of all Andean clades in Heliotropium are estimated to be of late Miocene or Pliocene ages. At least three independent Andean diversification events can be recognized within Heliotropium. Timing of the diversification in the Andean lineages Heliotropium sects.Heliothamnus, Cochranea, Heliotrophytum, Hypsogenia, Plagiomeris, Platygyne clearly correspond to a rapid, late Miocene uplift of the Andes and a Pliocene development of arid environments in South America. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Two new species of Leptanilloides Mann, 1823 (Formicidae: Dorylinae from the Andes of southern Ecuador

    Directory of Open Access Journals (Sweden)

    Thibaut Delsinne

    2015-10-01

    Full Text Available Two new species of Leptanilloides are described: L. copalinga Delsinne & Donoso sp. nov., and L. prometea Delsinne & Donoso sp. nov., based on workers collected in the leaf litter and soil of the Andes of southern Ecuador. Both species belong to the L. biconstricta species-group (formally diagnosed here. The metatibial gland, considered a synapomorphy for Dorylinae, is observed in L. prometea sp. nov. but seems absent in L. copalinga sp. nov. We provide a COI DNA barcode for both species and a revised key for the worker caste of all known species in the genus. We also describe a single male identified as a potential new Leptanilloides species on the basis of morphology. Furthermore, its mitochondrial COI gene sequence does not match any previously barcoded species. However, we refrain from giving it a specific name because of our lack of knowledge about the worker caste. So far, half of the 14 Leptanilloides species have been discovered above 1500 m in the mountain forests or páramos of the Ecuadorian Andes, confirming, if needed, the biological significance of these threatened habitats.

  4. Permafrost distribution map of San Juan Dry Andes (Argentina) based on rock glacier sites

    Science.gov (United States)

    Esper Angillieri, María Yanina

    2017-01-01

    Rock glaciers are frozen water reservoirs in mountainous areas. Water resources are important for the local populations and economies. The presence of rock glaciers is commonly used as a direct indicator of mountain permafrost conditions. Over 500 active rock glaciers have been identified, showing that elevations between 3500 and 4500 m asl., a south-facing or east-facing aspect, areas with relatively low solar radiation and low mean annual air temperature (-4 to 0 °C) favour the existence of rock glaciers in this region. The permafrost probability model, for Dry Andes of San Juan Province between latitudes 28º30‧S and 32°30‧S, have been analyzed by logistic regression models based on the active rock glaciers occurrence in relation to some topoclimatic variables such as altitude, aspect, mean annual temperature, mean annual precipitation and solar radiation, using optical remote sensing techniques in a GIS environment. The predictive performances of the model have been estimated by known rock glaciers locations and by the area under the receiver operating characteristic curve (AUROC). This regional permafrost map can be applied by the Argentinean Government for their recent initiatives which include creating inventories, monitoring and studying ice masses along the Argentinean Andes. Further, this generated map provides valuable input data for permafrost scenarios and contributes to a better understanding of our geosystem.

  5. Bare Rocks and Fallen Angels: Environmental Change, Climate Perceptions and Ritual Practice in the Peruvian Andes

    Directory of Open Access Journals (Sweden)

    Karsten Paerregaard

    2013-05-01

    Full Text Available One of the many dimensions of globalization is climate change that in recent years has caused much concern in the developed world. The aim of this article is to explore how people living on the margins of the global world conceive climate change. Drawing on ethnographic field data from the 1980s and today it examines how the ritual practice and the religious belief of a rural community in the Peruvian Andes has changed during the last 27 years and how the villagers perceive this change. It argues that the villagers traditionally conceive the environment as co-habited by humans and non-humans but that recent environmental change in the Andes has caused a shift in this world-view. Today, many villagers have adopted the global vocabulary on climate change and are concerned with their own impact in the environment. However, the villagers reject the idea that it is human activities in other parts of the world that cause environmental problems in their community and claim that these must be addressed locally. It suggests that even though the villagers’ reluctance to subscribe to the global discourse of climate change makes them look like the companions of climate skeptics in the developed world, their reasons are very different.

  6. East of the Andes: The genetic profile of the Peruvian Amazon populations.

    Science.gov (United States)

    Di Corcia, T; Sanchez Mellado, C; Davila Francia, T J; Ferri, G; Sarno, S; Luiselli, D; Rickards, O

    2017-06-01

    Assuming that the differences between the Andes and the Amazon rainforest at environmental and historical levels have influenced the distribution patterns of genes, languages, and cultures, the maternal and paternal genetic reconstruction of the Peruvian Amazon populations was used to test the relationships within and between these two extreme environments. We analyzed four Peruvian Amazon communities (Ashaninka, Huambisa, Cashibo, and Shipibo) for both Y chromosome (17 STRs and 8 SNPs) and mtDNA data (control region sequences, two diagnostic sites of the coding region, and one INDEL), and we studied their variability against the rest of South America. We detected a high degree of genetic diversity in the Peruvian Amazon people, both for mtDNA than for Y chromosome, excepting for Cashibo people, who seem to have had no exchanges with their neighbors, in contrast with the others communities. The genetic structure follows the divide between the Andes and the Amazon, but we found a certain degree of gene flow between these two environments, as particularly emerged with the Y chromosome descent cluster's (DCs) analysis. The Peruvian Amazon is home to an array of populations with differential rates of genetic exchanges with their neighbors and with the Andean people, depending on their peculiar demographic histories. We highlighted some successful Y chromosome lineages expansions originated in Peru during the pre-Columbian history which involved both Andeans and Amazon Arawak people, showing that at least a part of the Amazon rainforest did not remain isolated from those exchanges. © 2017 Wiley Periodicals, Inc.

  7. Fault-controlled development of shallow hydrothermal systems: Structural and mineralogical insights from the Southern Andes

    Science.gov (United States)

    Roquer, T.; Arancibia, G.; Rowland, J. V.; Iturrieta, P. C.; Morata, D.; Cembrano, J. M.

    2017-12-01

    Paleofluid-transporting systems can be recognized as meshes of fracture-filled veins in eroded zones of extinct hydrothermal systems. Here we conducted meso-microstructural analysis and mechanical modeling from two exhumed exposures of the faults governing regional tectonics of the Southern Andes: the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). A total of 107 fractures in both exposures were analyzed. The ATF specific segment shows two tectonic solutions that can be modeled as Andersonian and non-Andersonian tectonic regimes: (1) shear (mode II/III) failure occurs at differential stresses > 28 MPa and fluid pressures 85-98% lithostatic in the non-Andersonian regime. Additionally, the LOFS exposure cyclically fails in extension (mode I) or extension + shear (modes I + II/III) in the Andersonian regime, at differential stresses 40-80% lithostatic. In areas of spatial interaction between ATF and LOFS, these conditions might favor: (1) the storage of overpressured fluids in hydrothermal systems associated with the ATF faults, and (2) continuous fluid flow through vertical conduits in the LOFS faults. These observations suggest that such intersections are highly probable locations for concentrated hydrothermal activity, which must be taken into consideration for further geothermal exploration. ACKNOWLEDGEMENTS. PhD CONICYT grants, Centro de Excelencia en Geotermia de los Andes (CEGA-FONDAP/CONICYT Project #15090013), FONDECYT Project #1130030 and Project CONICYT REDES #140036.

  8. Cenozoic basin thermal history reconstruction and petroleum systems in the eastern Colombian Andes

    Science.gov (United States)

    Parra, Mauricio; Mora, Andres; Ketcham, Richard A.; Stockli, Daniel F.; Almendral, Ariel

    2017-04-01

    Late Mesozoic-Cenozoic retro-arc foreland basins along the eastern margin of the Andes in South America host the world's best detrital record for the study of subduction orogenesis. There, the world's most prolific petroleum system occur in the northernmost of these foreland basin systems, in Ecuador, Colombia and Venezuela, yet over 90% of the discovered hydrocarbons there occur in one single province in norteastern Venezuela. A successful industry-academy collaboration applied a multidisciplinary approach to the study of the north Andes with the aim of investigating both, the driving mechanisms of orogenesis, and its impact on hydrocarbon accumulation in eastern Colombia. The Eastern Cordillera is an inversion orogen located at the leading edge of the northern Andes. Syn-rift subsidence favored the accumulation of km-thick organic matter rich shales in a back-arc basin in the early Cretaceous. Subsequent late Cretaceous thermal subsidence prompted the accumulation of shallow marine sandstones and shales, the latter including the Turonian-Cenomanian main hydrocarbon source-rock. Early Andean uplift since the Paleocene led to development of a flexural basin, filled with mainly non-marine strata. We have studied the Meso-Cenozoic thermal evolution of these basins through modeling of a large thermochronometric database including hundreds of apatite and zircon fission-track and (U-Th)/He data, as well as paleothermometric information based on vitrinite reflectance and present-day temperatures measured in boreholes. The detrital record of Andean construction was also investigated through detrital zircon U-Pb geochronometry in outcrop and borehole samples. A comprehensive burial/exhumation history has been accomplished through three main modeling strategies. First, one-dimensional subsidence was used to invert the pre-extensional lithospheric thicknesses, the magnitude of stretching, and the resulting heat flow associated to extension. The amount of eroded section and

  9. Phytophthora viruses.

    Science.gov (United States)

    Cai, Guohong; Hillman, Bradley I

    2013-01-01

    Phytophthora sp. is a genus in the oomycetes, which are similar to filamentous fungi in morphology and habitat, but phylogenetically more closely related to brown algae and diatoms and fall in the kingdom Stramenopila. In the past few years, several viruses have been characterized in Phytophthora species, including four viruses from Phytophthora infestans, the late blight pathogen, and an endornavirus from an unnamed Phytophthora species from Douglas fir. Studies on Phytophthora viruses have revealed several interesting systems. Phytophthora infestans RNA virus 1 (PiRV-1) and PiRV-2 are likely the first members of two new virus families; studies on PiRV-3 support the establishment of a new virus genus that is not affiliated with established virus families; PiRV-4 is a member of Narnaviridae, most likely in the genus Narnavirus; and Phytophthora endornavirus 1 (PEV1) was the first nonplant endornavirus at the time of reporting. Viral capsids have not been found in any of the above-mentioned viruses. PiRV-1 demonstrated a unique genome organization that requires further examination, and PiRV-2 may have played a role in late blight resurgence in 1980s-1990s. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Schmallenberg Virus

    Indian Academy of Sciences (India)

    IAS Admin

    explore the potential of this infection crossing the species barrier and thereby .... The virus targets mainly the brain of the unborn animal resulting in neurological ... The virus is located in the blood of the adult infected animal or in the central ...

  11. Zika Virus

    Science.gov (United States)

    ... with facebook share with twitter share with linkedin Zika Virus Credit: NIAID A female Aedes mosquito. This type of mosquito can transmit Zika, ... transmitted to humans through the bite of infected Aedes aegypti mosquitoes. Zika virus can be transmitted from an infected pregnant woman ...

  12. CHANDIPURA VIRUS

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. CHANDIPURA VIRUS. First isolated from a village called Chandipura near Nagpur in 1965 in India. Belongs to rhabdoviridae family. Used as a Model System to study RNA virus multiplication in the infected cell at molecular level. Notes:

  13. The Wiphala Genomics: the deployment of molecular markers in small-scale potato crop systems in the Bolivian Andes

    NARCIS (Netherlands)

    Puente, D.

    2008-01-01

    The deployment of molecular markers in the small-scale potato systems in the Bolivian Andes takes place within two contradictory understandings of potato biodiversity. On the one hand, biodiversity is understood as raw material; farmers' varieties have no intrinsic value, value is added by breeders

  14. Late Pleistocene glaciations of the arid subtropical Andes and new results from the Chajnantor Plateau, northern Chile

    Science.gov (United States)

    Ward, Dylan J.; Cesta, Jason M.; Galewsky, Joseph; Sagredo, Esteban

    2015-11-01

    The spatiotemporal pattern of glaciation along the Andes Mountains is an important proxy record reflecting the varying influence of global and regional circulation features on South American climate. However, the timing and extent of glaciation in key parts of the orogen, particularly the deglaciated arid Andes, are poorly constrained. We present new cosmogenic 10Be and 36Cl exposure ages for glacial features on and near the Chajnantor Plateau (23 °S). The new dates, although scattered due to cosmogenic inheritance, imply that the most recent extensive glacial occupation ended before or during the global Last Glacial Maximum (LGM). We discuss this new record in the context of published glacial chronologies from glacial features in Peru, Bolivia, and northern Chile rescaled using the latest cosmogenic 10Be production rate calibration for the tropical Andes. The results imply regionally synchronous moraine stabilization ca. 25-40 ka, 15-17 ka, and 12-14 ka, with the youngest of these moraines absent in records south of ∼20 °S, including in our new Chajnantor area chronology. This spatial pattern implicates easterly moisture in generating sufficient snowfall to glaciate the driest parts of the Andes, while allowing a role for westerly moisture, possibly modulated by the migration of the Southern Westerly Wind belt, in the regions near and south of the Atacama Desert.

  15. Kas Arnold Rüütel valetas süümevannet andes? / Anneli Ammas, Garel Püüa

    Index Scriptorium Estoniae

    Ammas, Anneli, 1962-

    2006-01-01

    Autorite hinnangul tekib 31. augustil Eesti Ekspressis ilmunud artikli põhjal, milles käsitleti Johannes Hindi represseerimist, küsimus, kas Arnold Rüütel on valetanud Eesti Vabariigile korduvalt süümevannet andes. TÜ professori Kalle Meruski seisukoht. Lisa: Rüütel käskis kontrolli tugevdada

  16. An Ancestral Language to Speak with the "Other": Closing down Ideological Spaces of a Language Policy in the Peruvian Andes

    Science.gov (United States)

    Zavala, Virginia

    2014-01-01

    Using a multilayered, ethnographic and critical approach to language policy and planning, this article examines a language policy favoring Quechua in Apurímac in the Southern Peruvian Andes, which is being imagined as an integrated community unified by the local language. This study presents a case in which top-down policies open up ideological…

  17. Overriding plate shortening and extension above subduction zones : A parametric study to explain formation of the Andes Mountains

    NARCIS (Netherlands)

    Schellart, Wouter P.

    2008-01-01

    Mountain building above subduction zones, such as observed in the Andes, is enigmatic, and the key parameter controlling the underlying dynamics remains a matter of considerable debate. A global survey of subduction zones is presented here, illustrating the correlation between overriding plate

  18. New GPS velocity field in the northern Andes (Peru - Ecuador - Colombia): heterogeneous locking along the subduction, northeastwards motion of the Northern Andes

    Science.gov (United States)

    Nocquet, J.; Mothes, P. A.; Villegas Lanza, J.; Chlieh, M.; Jarrin, P.; Vallée, M.; Tavera, H.; Ruiz, G.; Regnier, M.; Rolandone, F.

    2010-12-01

    Rapid subduction of the Nazca plate beneath the northen Andes margin (~6 cm/yr) results in two different processes: (1) elastic stress is accumulating along the Nazca/South American plate interface which is responsible for one of the largest megathrust earthquake sequences during the last century. The 500-km-long rupture zone of the 1906 (Mw= 8.8) event was partially reactivated by three events from the 1942 (Mw = 7.8), 1958 (Mw = 7.7), to the 1979 (Mw = 8.2). However, south of latitude 1°S, no M>8 earthquake has been reported in the last three centuries, suggesting that this area is slipping aseismically (2) permanent deformation causes opening of the Gulf of Guayaquil, with northeastwards motion of the Northern Andean Block (NAB). We present a new GPS velocity field covering the northern Andes from south of the Gulf of Guayaquil to the Caribbean plate. Our velocity field includes new continuously-recording GPS stations installed along the Ecuadorian coast, together with campaign sites observed since 1994 in the CASA project (Kellogg et al., 1989). We first estimate the long-term kinematics of the NAB in a joint inversion including GPS data, earthquake slip vectors, and quaternary slip rates on major faults. The inversion provides an Euler pole located at long. -107.8°E, lat. 36.2°N, 0.091°/Ma and indicates little internal deformation of the NAB (wrms=1.2 mm/yr). As a consequence, 30% of the obliquity of the Nazca/South America motion is accommodated by transcurrent to transpressive motion along the eastern boundary of the NAB. Residual velocities with respect to the NAB are then modeled in terms Models indicate a patchwork of highly coupled asperities encompassed by aseismic patches over the area of rupture of the M~8.8 1906 earthquake. Very low coupling is found along the southern Ecuadorian and northern Peru subduction.

  19. Ensayos metodologicos para la investigacion de reservorios de Leishmania spp en los Andes venezolanos Methodological assay for research of reservoirs of Leishmania spp. in the Venezuelan Andes

    Directory of Open Access Journals (Sweden)

    Ana Lugo Yarbuh

    1982-12-01

    Full Text Available Se describen dos técnicas, presuntiva y confirmativa, para la investigación de mamíferos que pudieran ser reservorios de Leishmania que parasitan al hombre. Se investigan los cambios en los títulos de inmovilización y aglutinación de promastigotos de cultivo por los sueros de animales normales y expuestos una o varias veces a la inoculación intradérmica de pequeñas dosis de promastigotos vivos. Se registra una caída de los títulos de aglutinación en los sueros de hamsteres, de Holochilus venezuelae y de Didelphis marsupialis después de la inoculación con L. mexicana mexicana de Panamá y de L. gamhami de la región de los Andes venezolanos. Se discute la natureza de estos fenómenos. Se han hecho xenodiagnósticos con Lutzomyia townsendi en Holochilus venezuelae y Sigmodon hispidus infectados experimentalmente com L. mexicana mexicana, L. mexicana amazonensis, L. braziliensis y L. garnhami. Las pruebas fueron leidas mediante el examen microscópico de las gotitas de heces excretadas entre las 108 y 132 horas después de la ingesta infectante, tras colorearlas con Giemsa. Se obtuvieron resultados positivos en 23% de los experimentos usando mamíferos con lesiones localizadas, dejando a los flebótomos ingurgitarse libremente sobre animales anestesiados que poseian una hasta varias lesiones localizadas.Presumptive and confirmative techniques for searching mammals which could be reservoirs for Leishmania parasites from man are described. The changes of immobilising and agglutinating titers for promastigotes from culture by sera from normal and exposed mammals after single or repeated intradermal inoculation of promastigotes are described. A fall in titers of agglunation is observed in sera from hamsters, Holochilus venezuelae and Didelphis marsupialis after inoculation with L. mexicana mexicana from Panama and L. garnhami from the Venezuelan Andes region. The nature of this phenomenon is discussed. Xenodiagnoses were made with

  20. Estimation de l'aléa sismique dans les Andes nord équatoriennes

    Directory of Open Access Journals (Sweden)

    1996-01-01

    Full Text Available Les Andes Nord équatoriennes ont connu de nombreux séismes historiques destructeurs. Pour caractériser l’aléa sismique de la région andine, nous avons fait une révision critique de la sismicité historique et de l’ensemble des failles actives de l’Équateur. Les deux sources majeures de l’aléa sismique sont respectivement la subduction superficielle pour la région côtière et le système transpressif des hautes Andes pour la région andine. Ce système est composé de failles décrochantes dextres d’orientation N30-35°E (failles du Rio Chingual-La Sofia et Pallatanga qui limitent respectivement au Nord et au Sud des failles inverses N-S du relais compressif de la vallée interandine (failles de Quito et de Latacunga. L’étude des mécanismes au foyer superficiels des Andes équatoriennes nous a permis de calculer une vitesse de raccourcissement crustal de 4.6 mm/a selon une direction N92°E et d’estimer des temps de récurrence et des périodes de retour. Un séisme de Mw = 5 pourrait se produire tous les 0.5 an, de Mw = 6 tous les 4.5 ans, de Mw = 7 tous les 45.4 ans. De même, sur une période de temps de 33 ans, 66 séismes de Mw=5 peuvent être attendus, 7 séismes de Mw=6 et 1 séisme de Mw=7. Enfin, nous avons estimé pour l’ensemble des sources sismogènes de la région andine des magnitudes maximales probables et des temps de récurrence. Un séisme de magnitude 7 à 7.5 peut se produire sur la faille du Rio Chingual tous les 400±440 ans et de magnitude 6.7 à 7.2 tous les 380±320 ans sur la faille de Pallatanga. Dans la vallée interandine, la faille de Quito est susceptible d’engendrer un séisme de magnitude 6.6 à 7.6 tous les 930±300 ans. LA AMENAZA SÍSMICA EN LOS ANDES ECUATORIANOS. Los Andes del Norte del Ecuador son una región sismogénica mayor, donde se puede contabilizar muchos terremotos históricos destructores. A fin de determinar la amenaza sísmica sobre la región andina, se hizo la asociaci

  1. Cold Episodes, Their Precursors and Teleconnections in the Central Peruvian Andes (1958-2009)

    Science.gov (United States)

    Sulca, J. C.; Vuille, M. F.; Trasmonte, G.; Silva, Y.; Takahashi, K.

    2014-12-01

    The Mantaro valley (MV) is located in the central Peruvian Andes. Occasionally, cold episodes are observed during the austral summer (January-March), which strongly damage crops. However, little is known about the causes and impacts of such cold episodes in the MV. The main goal of this study is thus to characterize cold episodes in the MV and assess their large-scale circulation and teleconnections over South America (SA) during austral summer. To identify cold events in the MV daily minimum temperature for the period 1958-2009 from Huayao station, located within the MV was used. We defined a cold episode as the period when daily minimum temperature drops below the 10-percentile for at least one day. Several gridded reanalysis and satellite products were used to characterize the large-scale circulation, cloud cover and rainfall over SA associated with these events for same period. Cold episodes in the MV are associated with positive OLR anomalies, which extend over much of the central Andes, indicating reduced convective cloud cover during these extremes, but also affirm the large-scale nature of these events. At the same time, northeastern Brazil (NEB) registers negative OLR anomalies, strong convective activity and enhanced cloud cover because displacement of the South Atlantic Convergence Zone (SACZ) toward the northeast of its climatologic position. Further, it is associated with a weakening of the Bolivian High - Nordeste Low (BH-NL) system at upper levels, but also influenced by a low-level migratory high-pressure center develops at 30°S, 50°W; propagating from mid- to low latitudes as part of an extratropical Rossby wave train. In conclusion, cold episodes in the MV appear to be caused by radiative cooling associated with reduced cloudiness, rather than cold air advection. The reduced cloud cover in turn results from a robust large-scale pattern of westerly wind anomalies over central Peruvian Andes, inhibiting moisture influx, convective activity and

  2. Glacier monitoring and glacier-climate interactions in the tropical Andes: A review

    Science.gov (United States)

    Veettil, Bijeesh Kozhikkodan; Wang, Shanshan; Florêncio de Souza, Sergio; Bremer, Ulisses Franz; Simões, Jefferson Cardia

    2017-08-01

    In this review, we summarized the evolution of glacier monitoring in the tropical Andes during the last few decades, particularly after the development of remote sensing and photogrammetry. Advantages and limitations of glacier mapping, applied so far, in Venezuela, Colombia, Ecuador, Peru and Bolivia are discussed in detail. Glacier parameters such as the equilibrium line altitude, snowline and mass balance were given special attention in understanding the complex cryosphere-climate interactions, particularly using remote sensing techniques. Glaciers in the inner and the outer tropics were considered separately based on the precipitation and temperature conditions within a new framework. The applicability of various methods to use glacier records to understand and reconstruct the tropical Andean climate between the Last Glacial Maximum (11,700 years ago) and the present is also explored in this paper. Results from various studies published recently were analyzed and we tried to understand the differences in the magnitudes of glacier responses towards the climatic perturbations in the inner tropics and the outer tropics. Inner tropical glaciers, particularly those in Venezuela and Colombia near the January Intertropical Convergence Zone (ITCZ), are more vulnerable to increase in temperature. Surface energy balance experiments show that outer tropical glaciers respond to precipitation variability very rapidly in comparison with the temperature variability, particularly when moving towards the subtropics. We also analyzed the gradients in glacier response to climate change from the Pacific coast towards the Amazon Basin as well as with the elevation. Based on the current trends synthesised from recent studies, it is hypothesized that the glaciers in the inner tropics and the southern wet outer tropics will disappear first as a response to global warming whereas glaciers in the northern wet outer tropics and dry outer tropics show resistance to warming trends due to

  3. SRTM Colored Height and Shaded Relief: Laguna Mellquina, Andes Mountains, Argentina

    Science.gov (United States)

    2001-01-01

    This depiction of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM) view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters(2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U

  4. Macroinvertebrate community response to acid mine drainage in rivers of the High Andes (Bolivia)

    International Nuclear Information System (INIS)

    Van Damme, Paul Andre; Hamel, Caroli; Ayala, Alfredo; Bervoets, Lieven

    2008-01-01

    Several High Andes Rivers are characterized by inorganic water pollution known as acid mine drainage (AMD). The aim of this study was to assess the relationship between metal concentrations in the sediments and the macroinvertebrate communities in two river basins affected by AMD. In general, the taxon diversity of the macroinvertebrate community at the family level was low. The concentrations of Cd, Cu, Zn, Pb and Ni at mining sites were higher than at unpolluted sites. The pH of the water was alkaline (7.0-8.5) in unpolluted sites, whereas it dropped to very low values (<3) at mining sites. Redundancy Analysis (RDA) showed that pH was the best predictor of macroinvertebrate community richness. The number of macroinvertebrate families decreased gradually with increasing acidity, both in pools and riffles, though it is suggested that riffle communities were more affected because they are in closer contact with the acid water. - Community response to AMD

  5. How well do Important Bird Areas represent species and minimize conservation conflict in the tropical Andes?

    DEFF Research Database (Denmark)

    O´Dea, Niall; Bastos Araujo, Miguel; Whittaker, Robert J.

    2006-01-01

    to develop an efficient, integrated network of sites to represent priority species. Reserve selection algorithms may serve this end by optimizing complementarity in species representation among selected sites, whether these sites are adopted independently or as a supplement to the existing reserve network....... As tools of site selection, they may be particularly useful in areas such as the tropical Andes where complex patterns of species disjunction and co-occurrence make the development of representative reserve networks particularly difficult. Furthermore, they facilitate making spatially explicit choices...... about how reserve sites are located in relation to human populations. We advocate their use not in replacement of approaches such as the IBA initiative but as an additional, complementary tool in ensuring that such reserve networks are developed as efficiently as practically possible....

  6. Les Andes Centrales Tropicales vues par deux géographes: Isaiah Bowman et Carl Troll

    Directory of Open Access Journals (Sweden)

    1978-01-01

    Full Text Available Deux visions des Andes vues par deux géographes, Isaiah BOWMAN et Carl TROLL, au caractère et au milieu intellectuel différents. L'auteur étudie dans l'un et l'autre cas la méthode d'analyse de l'espace géographique et les conclusions tirées par chacun d'eux. I. BOWMAN, Américain, convaincu qu'une économie mercantiliste fondée sur l'exportation permettra aux Etats andins d'accéder à un modèle de développement, décrit les vastes contrées amazoniennes comme un futur El Dorado entre les mains de colons. L'aménagement des basses plaines selon des schémas nord-américains est le pilier de l'économie alors que les Andes abritant les communautés indigènes constituent un frein au développement. De ce fait il laisse de côté l'étude des paysanneries andines. Toute différente est la démarche de Carl TROLL dont la formation à la fois en sciences humaines et naturelles, lui permet de cerner l'espace géographique comme cadre de vie des sociétés. L'utilisation des étages écologiques, le développement de l'Empire Inca fondé sur l'étage des 'punas', la démarche historique des analyses minutieuses de Carl TROLL donne un éclairage nouveau aux relations des sociétés andines et des milieux naturels avec lesquels elles composent. Dos puntos de vista de los Andes por dos geógrafos, Isaiah BOWMAN y Carl TROLL con carácter y medio intelectual distintos. El autor estudia en ambos casos el método de análisis del espacio geográfico y las conclusiones sacadas por cada uno de ellos. I. BOWMAN, americano, convencido que una economía mercantil fundada sobre la exportación permitirá a los estados andinos acceder a un modelo de desarrollo, describe las extensas llanuras amazónicas como un El Dorado futuro entre las manos de los colonos. El desarrollo de las llanuras bajas según esquemas norteamericanos constituye el pilar de la economía mientras los Andes abrigando las comunidades indígenas se comportan como un freno al

  7. What facilitates adaptation? An analysis of community-based adaptation to environmental change in the Andes

    Directory of Open Access Journals (Sweden)

    Felipe Murtinho

    2016-02-01

    Full Text Available This study analyses the environmental, socio-economic andinstitutional factors that influence community-based adaptation strategies in 16municipalities in the rural Andes of Colombia. The study focuses specifically onthe factors that influence whether communities decide to take measures to managetheir water and micro-watersheds in response to water scarcity caused by climatevariability and land-use changes. The research uses quantitative and qualitativemethods incorporating data from surveys to 104 water user associations,precipitation and land-use data, municipal socio-economic information, and semistructured interviews with key informants. The results reveal 1 the links betweenenvironmental change and the type of adaptation that communities implement,and 2 how, in face of water scarcity changes, external funding facilitatesadaptation. The findings of this study contributes to the common-pool resourceand adaptation literatures by highlighting the important role that external actorsmay have in shaping collective action to adapt to environmental change.

  8. Diversity of the genus Polylepis (Rosaceae, Sanguisorbeae in the Peruvian Andes

    Directory of Open Access Journals (Sweden)

    Wilfredo Mendoza

    2011-08-01

    Full Text Available This study provides information on the diversity of Peruvian species of Polylepis. Nineteen (19 species are reported here (more than 70% of the 27 species registered for the whole Andean region. As a result, Peru could be considered as the country with the largest diversity of Polylepis species, in comparison with Bolivia (13, Ecuador (7, Argentina (4, Colombia (3, Chile (2, and Venezuela (1. The species occur in 19 departments of Peru, with the majority of them in Cusco (10 and Ayacucho (8. Species diversity is mostly concentrated in the Peruvian southern Andes (15 species, with the region becoming the potential center of diversification of the genus Polylepis. Regarding their altitudinal distribution, the greatest diversity (18 is found between 3000 and 4000 m.

  9. Chemical and isotopic investigations of runoff in a mountainous watershed, Venezuelan Andes (Rio Bocono)

    International Nuclear Information System (INIS)

    Cornieles, M.; Moreau, A.; Valles, V.; Travi, Y.

    1999-01-01

    The Rio Bocono watershed, located in the Western part of Venezuela on the South western side of Andes is considered by the 'Ministerio de1 Ambiente y de los Recursos Naturales Renovables' (MARN) as a priority zone for environmental management. The studies of relation between flow, dissolved elements and solid transport are essential to estimate soil degradation and sediment deposition which provokes loss of depth in the dam reservoir at the Southern margin of the basin. Because of the large surface which reach 1540 km 2 , the lack of equipment and the flash flood character of the river do not enable the flow mechanisms and transit times to be determined using usual hydrologic methods; therefore this problem has been approached by the way of chemical and isotopic investigation

  10. Black carbon and other light-absorbing impurities in the Andes of Northern Chile

    Science.gov (United States)

    Rowe, P. M.; Cordero, R.; Warren, S. G.; Pankow, A.; Jorquera, J.; Schrempf, M.; Doherty, S. J.; Cabellero, M.; Carrasco, J. F.; Neshyba, S.

    2015-12-01

    Black carbon (BC) and other light-absorbing impurities in snow absorb solar radiation and thus have the potential to accelerate glacial retreat and snowmelt. In Chile, glaciers and seasonal snow are important sources of water for irrigation and domestic uses. In July 2015 (Austral winter) we sampled snow in the western Andes in a north-south transect of Chile from 18 S to 34 S. Most of the sampled snow had fallen during a single synoptic event, during 11-13 July. The snow was melted and passed through 0.4 micrometer nuclepore filters. Preliminary estimates indicate that (1) the ratio of BC to dust in snow increases going south from Northern to Central Chile, and (2) in snow sampled during the two weeks following the snowstorm, the impurities were concentrated in the upper 5 cm of snow, indicating that the surface layer became polluted over time by dry deposition.

  11. Privatizing Water in the Chilean Andes: The Case of Las Vegas de Chiu-Chiu

    Directory of Open Access Journals (Sweden)

    Manuel Prieto

    2015-08-01

    Full Text Available The Chilean water model has been described as a textbook example of a free-market water system. This article contributes to the critiques of this model by showing the effect of its implementation in the Atacameño community of Chiu-Chiu, located in the Atacama Desert in the south-central Andes. In this community, the privatization of water rights ignored local water management practices that had produced a high-altitude wetland (known as a vega. This led to the inhabitants’ dispossession of crucial water rights and to wetland degradation. This process belies statements that the Chilean model relies on an unregulated market and instead highlights the state’s role in marginalizing local irrigation practices by reducing the water consumption of the indigenous population while keeping the copper mining industry (the main source of Chilean income and related growing urban populations supplied with water.

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

    Science.gov (United States)

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

    1984-01-01

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

  13. Mapping advanced argillic alteration zones with ASTER and Hyperion data in the Andes Mountains of Peru

    Science.gov (United States)

    Ramos, Yuddy; Goïta, Kalifa; Péloquin, Stéphane

    2016-04-01

    This study evaluates Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Hyperion hyperspectral sensor datasets to detect advanced argillic minerals. The spectral signatures of some alteration clay minerals, such as dickite and alunite, have similar absorption features; thus separating them using multispectral satellite images is a complex challenge. However, Hyperion with its fine spectral bands has potential for good separability of features. The Spectral Angle Mapper algorithm was used in this study to map three advanced argillic alteration minerals (alunite, kaolinite, and dickite) in a known alteration zone in the Peruvian Andes. The results from ASTER and Hyperion were analyzed, compared, and validated using a Portable Infrared Mineral Analyzer field spectrometer. The alterations corresponding to kaolinite and alunite were detected with both ASTER and Hyperion (80% to 84% accuracy). However, the dickite mineral was identified only with Hyperion (82% accuracy).

  14. A measurement of the cosmic microwave background from the high Chilean Andes

    Science.gov (United States)

    Miller, Amber Dawn

    A measurement of the angular spectrum of the Cosmic Microwave Background (CMB) between l = 50 and l = 400 is described. Data were obtained using HEMT radiometers at 30 and 40 GHz with angular resolutions of ≈1 deg and ≈0.7 deg respectively and with SIS based receivers at 144 GHz with angular resolution of ≈0.2 deg. Observations were made from Cerro Toco in the Chilean altiplano at an altitude of 17,000 feet in the Northern Chilean Andes. We find that the angular spectrum rises from l = 50 to a peak at l ≈ 200 and falls off at higher angular scales. A peak in the angular spectrum with amplitude, deltaTl ≈ 85muK is thus located for the first time with a single instrument at l ≈ 200. In addition, we find that the detected anisotropy has the spectrum of the CMB. Cosmological implications of this result are discussed.

  15. The role of biomass in a pilot town of Venezuelan Andes

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, A.; Sanchez, R.; Briceno, L.; Urbina, E. [Universidad de los Andes, Lab. de Bioenergia, Merida (Venezuela)

    1999-01-01

    This work analyses some factors of the energy crisis in a town of Venezuelan Andes (Llano del Hato, 3500 m.a.s.l.). The socioeconomics and climatic conditions in this region make the use of firewood as fuel mandatory. There are extensive desertified areas due to the extraction of plant species for firewood. It has been determined that there are diverse species in the area whose energy potential is superior to that reported in the literature, however, they are incorrectly used and are in danger of extinction. The absence of firewood drives peasants to use manure as a source of fuel. Parallel to the laboratory testing of different raw materials, a program of environmental education and optimisation of biomass to obtain energy is under way. It is hoped that pilot plans like this will expand to all of the Andean region. (Author)

  16. Pablo Palacio: Corporal Violence on Impossible Identities in the Zone of the Andes

    Directory of Open Access Journals (Sweden)

    Falconí Travez, Diego Fernando

    2012-01-01

    Full Text Available Pablo Palacio was an Ecuadorian writer who, in the 1920’s, built within his narrative a catalog of rare bodies with ambiguous and disturbing sexualities, characterizations that are quite different from ones portrayed in the Andean tradition to which Palacio belongs. Nonetheless one of the most issues striking facts of these characters is that their bodies are disciplined by certain discourses of power in a violent way. This paper explores trough literary theory such abuse and violence on women and homosexual identities in two of his stories. The aim of the paper is to investigate issues such as violence, economy of representation, its relationship with the literary text and vulnerability, as a sine qua non norm of abuse, in certain bodies in the area of the Andes.

  17. A new species of iguanid lizard, genus Stenocercus (Squamata, Iguania), from the Central Andes in Peru.

    Science.gov (United States)

    Venegas, Pablo J; Echevarría, Lourdes Y; García-Burneo, Karla; Koch, Claudia

    2016-12-04

    We describe a new species of Stenocercus from the montane forest of the right margin of the Marañón river in the northern portion of the Central Andes in northern Peru (Amazonas and La Libertad departments), at elevations ranging from 2300 to 3035 m. Stenocercus omari sp. nov. differs from other Stenocercus species, with the exception of S. amydrorhytus, S. chrysopygus, S. cupreus, S. johaberfellneri, S. latebrosus, S. melanopygus, S. modestus, S. ornatissimus, S. orientalis, and S. stigmosus, by having granular scales on the posterior surfaces of thighs, a conspicuous antehumeral fold and by lacking a vertebral crest. However, Stenocercus omari sp. nov. is easily distinguished from the aforementioned species, except S. orientalis, by the presence of prominently keeled dorsal head scales. The new species differs from S. orientalis by lacking a prominent oblique neck fold and by having a distinct deep postfemoral mite pocket.

  18. A new high-altitude species of centipede from the Andes of Ecuador (Chilopoda, Geophilomorpha, Schendylidae).

    Science.gov (United States)

    Pereira, Luis Alberto

    2018-01-18

    Pectiniunguis aequatorialis sp. nov. (Chilopoda: Geophilomorpha: Schendylidae) is described and illustrated on the basis of specimens collected in the Cayambe-Coca Ecological Reserve in the High Andes of Ecuador. The new species is characterized by having ventral pore-fields on the anterior region of the trunk only, a trait that is shared by a single Neotropical congener: Pectiniunguis ascendens Pereira, Minelli Barbieri, 1994 to which it is similar and is compared taxonomically. This is only the second report of a species of the genus Pectiniunguis Bollman, 1889 from mainland Ecuador. The other taxon is Pectiniunguis roigi Pereira, Foddai Minelli, 2001, so far only known from the type locality, Limoncocha (Sucumbíos Province), and herein reported for the first time from Parque Nacional Sumaco Napo-Galeras (Napo Province).

  19. Exploring pain in the Andes--learning from the Quichua (Inca) people experience.

    Science.gov (United States)

    Incayawar, Mario; Saucier, Jean-François

    2015-05-01

    There is a mounting recognition that culture profoundly shapes human pain experience. The 28 million indigenous people of the Andes in South America, mainly the Quichua (Inca) people, share a distinctive culture. However, little is known about their pain experience and suffering. The aim of the present study was to explore how Quichua adults perceive, describe, and cope with the pain. An exploratory qualitative/descriptive study was conducted with a convenience sample of 40 Quichua adults, including 15 women and 25 men, in the Northern Highlands of Ecuador. Data were collected through structured interviews of approximately 3 h, using a Quichua questionnaire called "The Nature of Pain" [Nanay Jahua Tapuicuna]. The interviews covered the notions of causation of pain, vulnerability to pain, responses to pain, aggravating factors, frequent locations of pain, types of pain, duration, characteristics of pain, control of pain, pathways to care, and preventive measures of pain. Basic descriptive analyses were performed. The Quichuas' pain experience is complex and their strategies to cope with it are sophisticated. According to the Quichuas, emotions, life events, co-morbid conditions, and spirits, among others factors play an important role in the origin, diagnosis, and treatment of pain. They strongly embrace biomedicine and physicians as well as Quichua traditional medicine and traditional healers. Family members and neighbors are also valuable sources of health care and pain control. The pathway to pain care that the Quichua people prefer is inclusive and pluralistic. The knowledge of the Quichua ethnographic "emic" details of their belief system and coping strategies to control pain are clinically useful not only for the health professional working in the Andes, some Quichua cultural characteristics related to pain could be useful to the culturally competent health practitioner who is making efforts to provide high-quality medical care in rural and multicultural

  20. Contenidos de uranio de lavas recientes en el sector sur de los Andes centrales

    Directory of Open Access Journals (Sweden)

    Guerra, N.

    1984-12-01

    Full Text Available We have studied the distribution of U in modern lava -flows of the southern part from the Central Andes (16°-28° S. For a given SiO2, content of the rocks, U abundance increases from west to east in a transects to the Andean Belt, while the depth of the subduction zone increases and the thickness of the continental curst decreases. Besides, U content tends to inerease steadly with the latitude, while the thick of the continental crust and the depth of the seismic zone decreases southward. Thus, on the basis of the available data, we are in a position to suggest that the U behavior in the studied lavas depends on the alkalanity and magmatic history of each volcanic center.

    Se presenta un estudio de distribución de U en lavas modernas del sector sur de los Andes centrales (16°-28° S. Para rocas de contenidos similares en SiO2 la abundancia de U crece de oeste a este en un perfil transversal al cordón andino, mientras que aumenta la profundidad de subducción, y disminuye la potencia de la corteza continental. Además, mientras la potencia de la corteza continental y la profundidad de la zona sísmica de Benioff disminuyen hacia el sur, U tiende a aumentar con la latitud. Así, y basado en los datos disponibles, estamos en posición de sugerir que el comportamiento de U en las rocas estudiadas, depende de la alcalinidad y de la historia magmática de cada centro volcánico.

  1. Trauma and violence in the Wari empire of the Peruvian Andes: warfare, raids, and ritual fights.

    Science.gov (United States)

    Tung, Tiffiny A

    2007-07-01

    This study examines bioarchaeological evidence for violence during the period of Wari imperialism in the Peruvian Andes through analysis of skeletal trauma from three populations dating to AD 650-800. The samples are from contemporaneous archaeological sites: Conchopata, a Wari heartland site in central highland Peru; Beringa, a community of commoners in the Majes valley of the southern Wari hinterland; and La Real, a high status mortuary site, also in the Majes valley. Given the expansionist nature of Wari and its military-related iconography and weaponry, it is hypothesized that Wari imperialism was concomitant with greater levels of violence relative to other prehispanic groups in the Andes. It is also hypothesized that differential articulation with the Wari empire (e.g., heartland vs. hinterland groups) affected the frequency and patterning of trauma. Results show that cranial trauma frequency of the three Wari era samples is significantly greater than several other Andean skeletal populations. This suggests that Wari rule was associated with high levels of violence, though it may not have always been related to militarism. The three adult samples show similar frequencies of cranial trauma (Conchopata = 26%; Beringa = 33%; La Real = 31%). This may suggest that differential positioning in the Wari empire had little effect on exposure to violence. Sex-based differences in cranial trauma frequencies are present only at La Real, but wound patterning differs between the sexes: females display more wounds on the posterior of the cranium, while males show more on the anterior. These data suggest that Wari rule may have contributed to violence. (c) 2007 Wiley-Liss, Inc.

  2. Volcanic impediments in the progressive development of pre-Columbian civilizations in the Ecuadorian Andes

    Science.gov (United States)

    Hall, Minard L.; Mothes, Patricia A.

    2008-10-01

    Archaeological investigations in Ecuador have proposed that there appear to be hiatus or anomalous jumps in the progressive development of pre-Columbian indigenous cultures, based upon the fact that their ceramics and tools demonstrate abrupt advances in their sophistication at several horizons in the soil profile. Because some of these horizons are clearly associated with volcanic ash layers, archaeologists have sought a causal relation with volcanism, that is, the eruptive events or their products severely interfered with the early inhabitants, resulting in their abandonment of certain areas. Geological studies of the young volcanoes in the Ecuadorian Andes carried out during the past two decades now allow us to make a more thorough evaluation of the role of volcanism during the Holocene. This contribution briefly describes the principal Holocene volcanic events and the distribution of the corresponding eruptive products found along the InterAndean Valley, from southern Colombia to central Ecuador. Only those events that were sufficiently large that they could have had a detrimental effect on the valley's early residents are discussed. Dacitic and rhyolitic ash flows, as well as numerous debris flows (lahars) have occurred frequently and their deposits cover many valleys and floodplains, where early inhabitants probably settled. The enormous Chillos Valley lahar, associated with the 4500 yBP eruption of Cotopaxi volcano, buried soils containing ceramics of the early Formative Period. However, the greatest impact upon mankind was probably not these short-lived violent events, but rather the burying of settlements and agricultural fields by ash fallout, the effect of which may have lasted hundreds of years. Ash fall layers are observed in pre-Columbian cultural horizons in the soil profile, occurring in the InterAndean Valley, the lower flanks of the Andes, and along Ecuador's Pacific coast, the oldest corresponding to the 5800 yBP eruption of Cotopaxi. This brief

  3. Tracing oxidative weathering from the Andes to the lowland Amazon Basin using dissoved rhenium

    Science.gov (United States)

    Dellinger, M.; Hilton, R. G.; West, A. J.; Torres, M.; Burton, K. W.; Clark, K. E.; Baronas, J. J.

    2016-12-01

    Over long timescales (>105 yrs), the abundance of carbon dioxide (CO2) in the atmosphere is determined by the balance of the major carbon sources and sinks. Among the major carbon sources, the oxidation of organic carbon contained within sedimentary rocks ("petrogenic" carbon, or OCpetro) is thought to result in CO2 emission of similar magnitude to that released by volcanism. Rhenium (Re) has been proposed as a proxy for tracing OCpetro oxidation. Here we investigate the source, behavior and flux of dissolved and particulate rhenium (Re) in the Madre de Dios watershed (a major Andean tributary of the Amazon River) and the lowlands, aiming to characterize the behavior of Re in river water and quantify the flux of CO2 released by OCpetro oxidation. Measured Re concentrations in Andean rivers range from 0.07 to 1.55 ppt. In the Andes, Re concentration do not change significantly with water discharge, whereas in the lowlands, Re concentration decrease at high water discharge. Mass balance calculation show that more than 70% of the dissolved Re is sourced from the oxidation of OCpetro the Andes-floodplain system. We calculate dissolved Re flux over a hydrological year to estimate the rates of oxidative weathering, and the associated CO2 release from OCpetro. Rates are high in the Andean headwaters, consistent with estimates from other mountain rivers with similar rates of physical erosion. We find evidence that a significant amount of additional oxidation (Re flux) happens during floodplain transport. These results have important implications for improving our understanding of the source and processes controlling Re in rivers, and allowing us to quantify long-term OCpetro cycling in large river basins.

  4. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    Science.gov (United States)

    Finer, Matt; Jenkins, Clinton N

    2012-01-01

    Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  5. Calcite Twin Analysis in the Central Andes of Northern Argentina and Southern Bolivia

    Science.gov (United States)

    Hardesty, E.; Hindle, D.

    2005-12-01

    The use of calcite twinning to infer compression directions and strain axes patterns has been applied widely in both fold and thrust belts, and continental interiors. Calcite twinning is noted to be one of the most precise methods for determining the internal strain of deformed rocks. Until now, such data from the deformed plate boundary of the Central Andes were lacking. This study has examined twinning orientations along the deformed Andean foreland (southern Bolivia and northern Argentina) from -25 to -20 latitude. In the Central Andes, we find an abundance of calcite twins in intervals of the Cretaceous age Yacorite limestone. Twin samples were collected, measured for orientation and type (I and II can be best used for strain analysis), and processed using the Groshong method, to give resultant strain tensors. The orientations of the twin short axes trend mostly NE-SW, which is close to the plate convergence direction. However, in a limited number of samples from the north, adjacent to the southern culmination of the active Subandean fold thrust belt, they trend NW-SE. This difference may be related to the more active, or more recent, shortening of the southern portion of the Eastern Cordillera, south of the culmination of the Subandean belt. This implies that twin short axes vary consistently with respect to geographic location and local tectonic regime. NW-SE trends in the northern region match well with fault kinematic studies in rocks pre-dating the San Juan del Oro unconformity (9-10 Ma). NE-SW trends in the south could correspond to much younger (~1-3 Ma) fault kinematic trends. In the Eastern Cordillera, where there is present day tectonic activity, the plunges of the twin short axes are found to be almost horizontal. This suggests that the twins were formed after folding occurred.

  6. Hydrological response in catchments whit debris covered glaciers in the semi-arid Andes, Chile

    Science.gov (United States)

    Caro, A.; McPhee, J.; MacDonell, S.; Pellicciotti, F.; Ayala, A.

    2016-12-01

    Glaciers in the semi-arid Andes Cordillera in Chile have shrank rapidly during the 20th century. Negative mass balance contributes to increase the surface area of debris-covered glaciers. Recent research in Chile suggests that contributions from glaciers to summer season river flow in dry years is very important, however hydrological processes determining the glacier contribution are still poorly understood in the region. This work seeks to determine appropriate parameters for the simulation of melt volume in two watersheds dominated by debris-covered glaciers, in order to understand its variability in time and space, in the area with the largest population in Chile. The hydrological simulation is performed for the Tapado (30°S) and Pirámide (33ºS) glaciers, which can be defined as cold and temperate respectively. To simulate the hydrological behaviour we adopt the physically-based TOPographic Kinematic wave APproximation model (TOPKAPI-ETH). The hydrometeorological records necessary model runs have been collected through fieldwork from 2013 to 2015. Regarding the calibration of the model parameters melting ETI, its observed that the value for TF in Pirámide is a third of the value for Tapado glacier, while SRF is half in Tapado regarding to Pirámide. The runoff in the glaciers, the constant snow and ice storage are higher in Tapado regarding Pirámide. Results show a contribution of glacial outflow to runoff during 2015 of 55% in Tapado and 77% in Pirámide, with maximum contributions between January and March in Tapado and Pirámide between November and March, presenting the relevance of the permanence of snow cover during spring and shelter that provides debris-covered in reducing the melting glacier. The results have allowed to know the relevance of the glacier contribution to mountain streams, allowing to know the calibration parameters most relevant in the hydrology balance of glacier basins in the Andes.

  7. Synchronous fire activity in the tropical high Andes: an indication of regional climate forcing.

    Science.gov (United States)

    Román-Cuesta, R M; Carmona-Moreno, C; Lizcano, G; New, M; Silman, M; Knoke, T; Malhi, Y; Oliveras, I; Asbjornsen, H; Vuille, M

    2014-06-01

    Global climate models suggest enhanced warming of the tropical mid and upper troposphere, with larger temperature rise rates at higher elevations. Changes in fire activity are amongst the most significant ecological consequences of rising temperatures and changing hydrological properties in mountainous ecosystems, and there is a global evidence of increased fire activity with elevation. Whilst fire research has become popular in the tropical lowlands, much less is known of the tropical high Andean region (>2000 masl, from Colombia to Bolivia). This study examines fire trends in the high Andes for three ecosystems, the Puna, the Paramo and the Yungas, for the period 1982-2006. We pose three questions: (i) is there an increased fire response with elevation? (ii) does the El Niño- Southern Oscillation control fire activity in this region? (iii) are the observed fire trends human driven (e.g., human practices and their effects on fuel build-up) or climate driven? We did not find evidence of increased fire activity with elevation but, instead, a quasicyclic and synchronous fire response in Ecuador, Peru and Bolivia, suggesting the influence of high-frequency climate forcing on fire responses on a subcontinental scale, in the high Andes. ENSO variability did not show a significant relation to fire activity for these three countries, partly because ENSO variability did not significantly relate to precipitation extremes, although it strongly did to temperature extremes. Whilst ENSO did not individually lead the observed regional fire trends, our results suggest a climate influence on fire activity, mainly through a sawtooth pattern of precipitation (increased rainfall before fire-peak seasons (t-1) followed by drought spells and unusual low temperatures (t0), which is particularly common where fire is carried by low fuel loads (e.g., grasslands and fine fuel). This climatic sawtooth appeared as the main driver of fire trends, above local human influences and fuel build

  8. Seasonal and high-resolution variability in hydrochemistry of the Andes-Amazon

    Science.gov (United States)

    Burt, E.; West, A. J.

    2017-12-01

    Stream hydrochemistry acts as a record of integrated catchment processes such as the amount of time it takes precipitation to flow through the subsurface and become streamflow (water transit times), water-rock interaction and biogeochemical cycling. Although it is understood that sampling interval affects observed patterns in hydrochemistry, most studies collect samples on a weekly, bi-weekly or monthly schedule due to lack of resources or the difficulty of maintaining automated sampling devices. Here, we attempt to combine information from two sampling time scales, comparing a year-long hydrochemical time series to data from a recent sub-daily sampling campaign. Starting in April 2016, river, soil and rain waters have been collected every two weeks at five small catchments spanning the tropical Andes and Amazon - a natural laboratory for its gradients in topography, erosion rates, precipitation, temperature and flora. Between January and March, 2017, we conducted high frequency sampling for approximately one week at each catchment, sampling at least every four hours including overnight. We will constrain young water fractions (Kirchner, 2016) and storm water fluxes for the experimental catchments using stable isotopes of water as conservative tracers. Major element data will provide the opportunity to make initial constraints on geochemical and hydrologic coupling. Preliminary results suggest that in the Amazon, hydrochemistry patterns are dependent on sampling frequency: the seasonal cycle in stable isotopes of water is highly damped, while the high resolution sampling displays large variability. This suggests that a two-week sampling interval is not frequent enough to capture rapid transport of water, perhaps through preferential flow networks. In the Andes, stable isotopes of water are highly damped in both the seasonal and high resolution cycle, suggesting that the catchment behaves as a "well-mixed" system.

  9. Reasons for an outstanding plant diversity in the tropical Andes of Southern Ecuador

    Directory of Open Access Journals (Sweden)

    Michael Richter

    2009-06-01

    Full Text Available Long-term field studies in the scope of a multidisciplinary project in southern Ecuador revealed extraordinary high species numbers of many organismic groups. This article discusses reasons for the outstanding vascular plant diversity using a hierarchical scale-oriented top-down approach (Grüninger 2005, from the global scale to the local microscale. The global scale explains general (paleo- ecological factors valid for most parts of the humid tropics, addressing various hypotheses and theories, such as the “greater effective evolutionary time”, constant input of “accidentals”, the “seasonal variability hypothesis”, the “intermediate disturbance hypothesis”, and the impact of soil fertility. The macroscale focuses on the Andes in northwestern South America. The tropical Andes are characterised by many taxa of restricted range which is particularly true for the Amotape-Huancabamba region, i.e. the so called Andean Depression, which is effective as discrete phytogeographic transition as well as barrier zone. Interdigitation of northern and southern flora elements, habitat fragmentation, geological and landscape history, and a high speciation rate due to rapid genetic radiation of some taxa contribute to a high degree of diversification. The mesoscale deals with the special environmental features of the eastern mountain range, the Cordillera Real and surrounding areas in southern Ecuador. Various climatic characteristics, the orographic heterogeneity, the geologic and edaphic conditions as well as human impact are the most prominent factors augmenting plant species diversity. On microscale, prevailing regimes of disturbance and environmental stresses, the orographic basement, as well as the general role on the various mountain chains are considered. Here, micro-habitats e.g. niches for epiphytes, effects of micro-relief patterns, and successions after small-sized disturbance events are screened. Direct effects of human impact are

  10. Changes in Andes snow cover from MODIS data, 2000-2016

    Science.gov (United States)

    Saavedra, Freddy A.; Kampf, Stephanie K.; Fassnacht, Steven R.; Sibold, Jason S.

    2018-03-01

    The Andes span a length of 7000 km and are important for sustaining regional water supplies. Snow variability across this region has not been studied in detail due to sparse and unevenly distributed instrumental climate data. We calculated snow persistence (SP) as the fraction of time with snow cover for each year between 2000 and 2016 from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensors (500 m, 8-day maximum snow cover extent). This analysis is conducted between 8 and 36° S due to high frequency of cloud (> 30 % of the time) south and north of this range. We ran Mann-Kendall and Theil-Sens analyses to identify areas with significant changes in SP and snowline (the line at lower elevation where SP = 20 %). We evaluated how these trends relate to temperature and precipitation from Modern-Era Retrospective Analysis for Research and Applications-2 (MERRA2) and University of Delaware datasets and climate indices as El Niño-Southern Oscillation (ENSO), Southern Annular Mode (SAM), and Pacific Decadal Oscillation (PDO). Areas north of 29° S have limited snow cover, and few trends in snow persistence were detected. A large area (34 370 km2) with persistent snow cover between 29 and 36° S experienced a significant loss of snow cover (2-5 fewer days of snow year-1). Snow loss was more pronounced (62 % of the area with significant trends) on the east side of the Andes. We also found a significant increase in the elevation of the snowline at 10-30 m year-1 south of 29-30° S. Decreasing SP correlates with decreasing precipitation and increasing temperature, and the magnitudes of these correlations vary with latitude and elevation. ENSO climate indices better predicted SP conditions north of 31° S, whereas the SAM better predicted SP south of 31° S.

  11. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    Directory of Open Access Journals (Sweden)

    Matt Finer

    Full Text Available Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1 There is a critical need for further strategic regional and basin scale evaluation of dams. 2 There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3 Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  12. Modeling Soil Organic Carbon Variation Along Climatic and Topographic Trajectories in the Central Andes

    Science.gov (United States)

    Gavilan, C.; Grunwald, S.; Quiroz, R.; Zhu, L.

    2015-12-01

    The Andes represent the largest and highest mountain range in the tropics. Geological and climatic differentiation favored landscape and soil diversity, resulting in ecosystems adapted to very different climatic patterns. Although several studies support the fact that the Andes are a vast sink of soil organic carbon (SOC) only few have quantified this variable in situ. Estimating the spatial distribution of SOC stocks in data-poor and/or poorly accessible areas, like the Andean region, is challenging due to the lack of recent soil data at high spatial resolution and the wide range of coexistent ecosystems. Thus, the sampling strategy is vital in order to ensure the whole range of environmental covariates (EC) controlling SOC dynamics is represented. This approach allows grasping the variability of the area, which leads to more efficient statistical estimates and improves the modeling process. The objectives of this study were to i) characterize and model the spatial distribution of SOC stocks in the Central Andean region using soil-landscape modeling techniques, and to ii) validate and evaluate the model for predicting SOC content in the area. For that purpose, three representative study areas were identified and a suite of variables including elevation, mean annual temperature, annual precipitation and Normalized Difference Vegetation Index (NDVI), among others, was selected as EC. A stratified random sampling (namely conditioned Latin Hypercube) was implemented and a total of 400 sampling locations were identified. At all sites, four composite topsoil samples (0-30 cm) were collected within a 2 m radius. SOC content was measured using dry combustion and SOC stocks were estimated using bulk density measurements. Regression Kriging was used to map the spatial variation of SOC stocks. The accuracy, fit and bias of SOC models was assessed using a rigorous validation assessment. This study produced the first comprehensive, geospatial SOC stock assessment in this

  13. Sensitivity of glaciation in the arid subtropical Andes to changes in temperature, precipitation, and solar radiation

    Science.gov (United States)

    Vargo, L. J.; Galewsky, J.; Rupper, S.; Ward, D. J.

    2018-04-01

    The subtropical Andes (18.5-27 °S) have been glaciated in the past, but are presently glacier-free. We use idealized model experiments to quantify glacier sensitivity to changes in climate in order to investigate the climatic drivers of past glaciations. We quantify the equilibrium line altitude (ELA) sensitivity (the change in ELA per change in climate) to temperature, precipitation, and shortwave radiation for three distinct climatic regions in the subtropical Andes. We find that in the western cordillera, where conditions are hyper-arid with the highest solar radiation on Earth, ELA sensitivity is as high as 34 m per % increase in precipitation, and 70 m per % decrease in shortwave radiation. This is compared with the eastern cordillera, where precipitation is the highest of the three regions, and ELA sensitivity is only 10 m per % increase in precipitation, and 25 m per % decrease in shortwave radiation. The high ELA sensitivity to shortwave radiation highlights the influence of radiation on mass balance of high elevation and low-latitude glaciers. We also consider these quantified ELA sensitivities in context of previously dated glacial deposits from the regions. Our results suggest that glaciation of the humid eastern cordillera was driven primarily by lower temperatures, while glaciations of the arid Altiplano and western cordillera were also influenced by increases in precipitation and decreases in shortwave radiation. Using paleoclimate records from the timing of glaciation, we find that glaciation of the hyper-arid western cordillera can be explained by precipitation increases of 90-160% (1.9-2.6× higher than modern), in conjunction with associated decreases in shortwave radiation of 7-12% and in temperature of 3.5 °C.

  14. Disappearance of the glacier on Mama Cotacachi: ethnoecological research and climate change in the Ecuadorian Andes

    Directory of Open Access Journals (Sweden)

    Rhoades, R.

    2008-12-01

    Full Text Available A first documented case study of a disappearing glacier in the snow capped volcano Cotacahi in Ecuador is presented with the studies belonging to the social sciences in relation to climate change and its impact on the population of the Equatorial Andes. With the use of multiple source methodology, including ethnographic analyzes, visual representations, repetitive photography, critical mapping by the local communities, longitudinal surveys, even archival research, as well as interviews to social actors and utilization of spatial data in a geographical information system (GIS. It is concluded that the documented disappearance of the glacier on the Cotacahi serves as an urgent call for action to the important dearth of social research related to global change from the ethnoecological perspective, with a cultural, local approach.

    Se presenta el primer estudio documentado de la desaparición del glaciar del nevado Cotacachi en el Ecuador, con los estudios que corresponden a las ciencias sociales en relación con el cambio climático y su impacto en la población de los Andes ecuatoriales. Mediante el uso de una metodología que incluye análisis etnográficos, representaciones visuales, fotografía repetitiva, mapeo crítico por parte de las comunidades locales, encuestas longitudinales e incluso investigación de archivos, así como también entrevistas a actores sociales, y utilización de los datos espaciales en un sistema de información geográfica (SIG. Se concluye que la desaparición documentada del glaciar del Cotacachi sirve como una llamada de atención urgente a la importante falta de investigaciones sociales relacionadas con el cambio global desde el punto de vista etnoecológico, con un enfoque cultural local.

  15. Cronología, identidad, urbanismo y estado en los Andes Centrales y surcentrales entre los siglos V a X D.C.: algunas reflexiones finales

    OpenAIRE

    Kaulicke, Peter

    2012-01-01

    Chronology, Identity, Urbanism and State in the Central and South Central Andes between V and X Centuries AD: Some Final ConclusionsThe article doesn´t have an abstract El artículo no presenta resumen

  16. Ethnoecology of the tropical Andes avian indicators of landscape change in highland Ecuador.

    Directory of Open Access Journals (Sweden)

    Sarmiento, F. O.

    2005-12-01

    Full Text Available Four Andean birds offer clues to rethink the ethnoecology of neotropical cloud forests, challenging the notion of conservation based only in water resources and biodiversity. Using both archaeological and actuoecological evidence, the role of humans in shaping high Andean landscapes' location and maintenance is argued as an important factor for conservation priorities of tropical montane cloud forests, particularly in the equatorial mountains. Avian examples demonstrate intricate linkages of culture and nature in the tropical Andes. Traditional knowledge associated to ornithological clues, helps understanding the dynamics of cultural landscapes, with birds as proxy of synergisms affecting the complexities of both, nature and culture. A paradox of conservation is highlighted with avian indicators. The four selected species were cases where landscape change and biodiversity help in determining ethnoecological insights. Unlike the preservation of absolute nature reserves, landscape stewardship, conservation easements and cultural la^tdscapes are listed as options for inclusion in the repertoire of conservation scenarios for cloud forests survival, which includes sacred places and spiritual domains as intangibles worth protecting in the Tropical Andes.

    [fr] Quatre oiseaux andins nous donnent des raisons pour repenser Vethnoécologie des forêts néotropicales humides, ce qui met en question l'idée de la conservation basée sur les ressources d'eau et la biodiversité seules. En se servant des évidences archéologiques et écologiques actuelles, on soutient que les êtres humains ont un rôle dans la formation des hauts paysages andins. On soutient aussi que l'entretien est un facteur important dans la conservation des forêts tropicales humides en montagne, surtout dans les montagnes équatoriales. Les exemples aviaires démontrent les liens compliqués entre la culture et la nature dans les Andes tropicales. Les connaissances

  17. Ganjam virus.

    Science.gov (United States)

    Sudeep, A B; Jadi, R S; Mishra, A C

    2009-11-01

    Ganjam virus (GANV), a member of genus Nairovirus of family Bunyavirdae is of considerable veterinary importance in India. Though, predominantly tick borne, GANV was also isolated from mosquitoes, man and sheep. Neutralizing and complement fixing antibodies to GANV have been detected in animal and human sera collected from different parts of the country. Thirty three strains of GANV have been isolated from India, mainly from Haemaphysalis ticks. The virus replicated in certain vertebrate and mosquito cell lines and found pathogenic to laboratory animals. One natural infection and five laboratory-acquired infections in men were also reported. GANV is antigenically related to Nairobi sheep disease virus (NSDV) of Africa, which is highly pathogenic for sheep and goats causing 70-90 per cent mortality among the susceptible population. Recent molecular studies have demonstrated that GANV is an Asian variant of NSDV and both these viruses are related to the dreaded Crimean Congo haemorrhagic fever (CCHF) group viruses. The versatility of the virus to replicate in different arthropod species, its ability to infect sheep, goat and man makes it an important zoonotic agent.

  18. Powassan (POW) Virus Basics

    Science.gov (United States)

    ... Health Professionals Related Topics For International Travelers Powassan Virus Disease Basics Download this fact sheet formatted for ... Virus Disease Fact Sheet (PDF) What is Powassan virus? Powassan virus is a tickborne flavivirus that is ...

  19. Caracterización morfométrica de la microcuenca de la quebrada los Andes, El Carmen de Viboral, Antioquia-Colombia Morphometrical characterization in los Andes watershed, El Carmen de Viboral, Antioquia-Colombia

    Directory of Open Access Journals (Sweden)

    Yimmy Montoya Moreno

    2009-07-01

    Full Text Available Se evaluaron algunas características morfométricas básicas en la microcuenca de la quebrada Los Andes en el departamento de Antioquia (Colombia. La microcuenca tiene un área pequeña (Some morphometric characteristic were evaluated in the watershed of creek Los Andes department of Antioquia (Colombia. The headwater has a small area (<20km² with main direction in the axis S-N, with an elevation range between 2.700 and 2.200 m. asl. It presents a network of drainage well structured, for which presents a time of concentration of the water over 5 hours. The watershed is of class Kc2 with a high slope and a system of drainage subdendritic. This research permitted to identify the uses of the soil, being the adequate use the one that presented greater percentage (55% and the use is recommended conservationist in general for all headwater.

  20. Nuclear Data for Safe Operation and Waste Transmutation: ANDES (Accurate Nuclear Data for nuclear Energy Sustainability); Datos nucleares para la operacion segura y la transmutacion de residuos: Andes (Datos Nucleares Precisos para la Sostenibilidad de la Energia Nuclear)

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E. M.

    2014-07-01

    Nuclear research within the 7th Framework Program (FP7 and FP7+2) of EURATOM has devoted a significant fraction of its efforts to the development of advanced nuclear fuel cycles and reactor concepts, mainly fast reactors, aiming to improve the long term sustainability by reduction of the final wastes, optimal use of natural resources and improvement of safety in the present and future nuclear installations. The new design need more accurate basic nuclear data for isotopes, like minor actinides, potentially playing an important role in the operation, fuel concept, safety or final wastes of those reactors and fuel cycles. Four projects, ANDES, ERINDA, EUFRAT and CHANDA, supported by EURATOM within the FP7 and FP7+2, have put together most of the European Nuclear Data community to respond efficiently and in a coordinated way to those needs. This paper summarizes the objectives, and main achievements of ANDES, the project responsible for most of the measurements and technical achievements that was coordinated by CIEMAT. Indeed, CIEMAT has coordinated the nuclear data R and D projects within EURATOM during the last 7 years (NUDATRA domain of EUROTRANS, and ANDES) and will continue this coordination in the CHANDA project till 2017. (Author)

  1. Distribución de Stenocercus guentheri (Sauria: Iguanidae en el sur de los Andes de Colombia

    Directory of Open Access Journals (Sweden)

    Castro Herrera Fernando

    1993-12-01

    Full Text Available The morphology of a population of Stenocercus guentherifrom Colombia is described in detail and compared to information from ecuadorean specimens. The range of the species is extended northward to include the colombian departments (provinces of Nariño and Cauca along the Andes. Some field observations about bahavior, habitat, and reproduction are included.El presente trabajo describe las características de Stenocercus guentheri, en las poblaciones del sur de Colombia y hace una comparación con la información del Ecuador. Se amplía su rango de distribución geográfica hacia el norte de Suramérica, incluyendo los departamentos de Nariño y Cauca en los Andes de Colombia. Se incluyen datos de campo sobre hábitat, hábitos y reproducción.

  2. Quantitative Temperature Reconstructions from Holocene and Late Glacial Lake Sediments in the Tropical Andes using Chironomidae (non-biting midges)

    Science.gov (United States)

    Matthews-Bird, F.; Gosling, W. D.; Brooks, S. J.; Montoya, E.; Coe, A. L.

    2014-12-01

    Chironomidae (non-biting midges) is a family of two-winged aquatic insects of the order Diptera. They are globally distributed and one of the most diverse families within aquatic ecosystems. The insects are stenotopic, and the rapid turnover of species and their ability to colonise quickly favourable habitats means chironomids are extremely sensitive to environmental change, notably temperature. Through the development of quantitative temperature inference models chironomids have become important palaeoecological tools. Proxies capable of generating independent estimates of past climate are crucial to disentangling climate signals and ecosystem response in the palaeoecological record. This project has developed the first modern environmental calibration data set in order to use chironomids from the Tropical Andes as quantitative climate proxies. Using surface sediments from c. 60 lakes from Bolivia, Peru and Ecuador we have developed an inference model capable of reconstructing temperatures, with a prediction error of 1-2°C, from fossil assemblages. Here we present the first Lateglacial and Holocene chironomid-inferred temperature reconstructions from two sites in the tropical Andes. The first record, from a high elevation (4153 m asl) lake in the Bolivian Andes, shows persistently cool temperatures for the past 15 kyr, punctuated by warm episodes in the early Holocene (9-10 kyr BP). The chironomid-inferred Holocene temperature trends from a lake sediment record on the eastern Andean flank of Ecuador (1248 m asl) spanning the last 5 millennia are synchronous with temperature changes in the NGRIP ice core record. The temperature estimates suggest along the eastern flank of the Andes, at lower latitudes (~1°S), climate closely resemble the well-established fluctuations of the Northern Hemisphere for this time period. Late-glacial climate fluctuations across South America are still disputed with some palaeoecological records suggesting evidence for Younger Dryas

  3. The analytic nodal diffusion solver ANDES in multigroups for 3D rectangular geometry: Development and performance analysis

    International Nuclear Information System (INIS)

    Lozano, Juan-Andres; Garcia-Herranz, Nuria; Ahnert, Carol; Aragones, Jose-Maria

    2008-01-01

    In this work we address the development and implementation of the analytic coarse-mesh finite-difference (ACMFD) method in a nodal neutron diffusion solver called ANDES. The first version of the solver is implemented in any number of neutron energy groups, and in 3D Cartesian geometries; thus it mainly addresses PWR and BWR core simulations. The details about the generalization to multigroups and 3D, as well as the implementation of the method are given. The transverse integration procedure is the scheme chosen to extend the ACMFD formulation to multidimensional problems. The role of the transverse leakage treatment in the accuracy of the nodal solutions is analyzed in detail: the involved assumptions, the limitations of the method in terms of nodal width, the alternative approaches to implement the transverse leakage terms in nodal methods - implicit or explicit -, and the error assessment due to transverse integration. A new approach for solving the control rod 'cusping' problem, based on the direct application of the ACMFD method, is also developed and implemented in ANDES. The solver architecture turns ANDES into an user-friendly, modular and easily linkable tool, as required to be integrated into common software platforms for multi-scale and multi-physics simulations. ANDES can be used either as a stand-alone nodal code or as a solver to accelerate the convergence of whole core pin-by-pin code systems. The verification and performance of the solver are demonstrated using both proof-of-principle test cases and well-referenced international benchmarks

  4. High-resolution paleoclimate records of Holocene hydroclimatic variability in the Eastern Colombian Andes from Lago de Tota

    Science.gov (United States)

    Ahmed, M. N.; Bird, B. W.; Escobar, J.; Polissar, P. J.

    2017-12-01

    The Northern Hemisphere (NH) South American Monsoon (SAM) is a significant source of precipitation for the North Andes (north of 0˚) and has major control over regional hydroclimate variability. Holocene-length histories of NH SAM variability are few compared to the Southern Hemisphere (SH), limiting understanding of how these systems are connected on orbital and shorter timescales. Here, we present multi-proxy lake-sediment-based paleoclimate and paleohydrologic reconstructions from Lago de Tota, Colombia, using sedimentological, geochemical and leaf-wax hydrogen isotopic indicators from radiometically dated cores. The results indicate periods of wet and dry climate phases during the past 9000 BP with an average Holocene sedimentation rate 33cm/kyr. An increase in total organic matter (TOM) content and finer grain-size distributions was observed from 8000 to 3200 BP, suggesting a period of high lake level. This was followed by lower TOM and coarser grain sizes, suggesting lower lake levels from 3200 BP to the present. Although Tota's lake level pattern is antiphased with other lake level reconstructions from the NH and SH Andes, it is consistent with hypothesized changes in atmospheric convection over the Andes during the Holocene and the way in which they would be modified by the so-called dry island effect in the Colombian Andes. This suggests that a common forcing mechanism can be invoked to explain differing millennial-scale Andean hydroclimate changes, namely atmospheric convection. Orbital and Pacific atmosphere-forcing are therefore likely to have played a significant role in driving pan-Andean hydroclimate variability based on their inter-hemispheric influence on Andean convection.

  5. CARACTERIZACIÓN FÍSIOGRÁFICA DE LA PUNA DE SAJAMA, CORDILLERA OCCIDENTAL DE LOS ANDES (BOLIVIA

    Directory of Open Access Journals (Sweden)

    Fernando Javier Santa Cecilia Mateos

    2015-01-01

    Full Text Available Este artículo aproxima a la realidad física de la cordillera Occidental de los Andes. Un espacio geográfico donde los caracteres geológicos relacionados con el vulcanismo adquieren una relevancia especial en la configuración del paisaje andino. Los nevados y llanuras intermedias o altiplanos, son los dos elementos que constituyen la imagen de la puna andina, un territorio situado por encima de los 4.000 metros, ámbito intermedio entre los valles húmedos o yungas y las más altas cumbres de los Andes. A la singularidad volcánica habría que añadir la relacionada con el modelado glaciar, los aspectos hidrográficos y la biogeografia en esta área. El artículo toma como ejemplo de estudio la puna de Sajama en eldepartamento de Oruro, en la frontera boliviano-chilena.Abstract. This article approaches the physical reality of the Western Cordillera of the Andes. A geographical space where characters related geological volcanism are of particular importance in shaping the landscape Andean. The intermediate plains or mountains and plateaus, are the two elements that make up the image of the Andean puna, an area located above 4,000 meters, the middle ground between Yungas wet valley and the highest peaks of the Andes. A volcanic uniqueness should add that related to glacier modeling, hydrographic aspects and biogeography in this area. The article uses the example of the highlands of Sajama study in thedepartment of Oruro in Bolivian-Chilean border.

  6. Mammalian carnivore occupancy is inversely related to presence of domestic dogs in the high Andes of Ecuador.

    Science.gov (United States)

    Zapata-Ríos, Galo; Branch, Lyn C

    2018-01-01

    Although the Andes have long been occupied by people, habitat loss, fragmentation through deforestation, and other human activities such as introduction of invasive species have increased drastically during the past century. The Ecuadorian Andes are considered a biodiversity hotspot. However, the fauna and threats to the region are poorly studied, and understanding of factors that shape the distribution of species in habitats disturbed by human activities is needed to identify and mitigate region-wide threats to wildlife. We evaluated factors associated with patterns of occurrence of Andean carnivores in landscapes of the northern Ecuadorian Andes, particularly habitat loss, fragmentation, and occupancy of domestic dogs, and determined whether thresholds occurred for these factors beyond which carnivore occurrence declined markedly. Five study areas (each 20 x 20 km) were surveyed with a total effort of 2,800 camera trap nights. Occupancies of four of the eight carnivores known from the region were best predicted by occupancy of domestic dogs rather than measures of habitat loss and fragmentation [Andean fox (Pseudalopex culpaeus), puma (Puma concolor), striped hog-nosed skunk (Conepatus semistriatus), and Andean bear (Tremarctos ornatus)]. The two largest carnivores, puma and Andean bear, demonstrated significant threshold responses to the presence of domestic dogs at two sites. Four smaller carnivores were recorded too infrequently to model occupancy, and at least two of these species appear to be in decline. The magnitude of domestic dog impacts on native species in tropical areas like the Ecuadorian Andes currently are not recognized. Results of our study indicate that small and large carnivores are in urgent need of conservation and clearly point to dogs as a significant threat to a broad range of native species.

  7. Mammalian carnivore occupancy is inversely related to presence of domestic dogs in the high Andes of Ecuador.

    Directory of Open Access Journals (Sweden)

    Galo Zapata-Ríos

    Full Text Available Although the Andes have long been occupied by people, habitat loss, fragmentation through deforestation, and other human activities such as introduction of invasive species have increased drastically during the past century. The Ecuadorian Andes are considered a biodiversity hotspot. However, the fauna and threats to the region are poorly studied, and understanding of factors that shape the distribution of species in habitats disturbed by human activities is needed to identify and mitigate region-wide threats to wildlife. We evaluated factors associated with patterns of occurrence of Andean carnivores in landscapes of the northern Ecuadorian Andes, particularly habitat loss, fragmentation, and occupancy of domestic dogs, and determined whether thresholds occurred for these factors beyond which carnivore occurrence declined markedly. Five study areas (each 20 x 20 km were surveyed with a total effort of 2,800 camera trap nights. Occupancies of four of the eight carnivores known from the region were best predicted by occupancy of domestic dogs rather than measures of habitat loss and fragmentation [Andean fox (Pseudalopex culpaeus, puma (Puma concolor, striped hog-nosed skunk (Conepatus semistriatus, and Andean bear (Tremarctos ornatus]. The two largest carnivores, puma and Andean bear, demonstrated significant threshold responses to the presence of domestic dogs at two sites. Four smaller carnivores were recorded too infrequently to model occupancy, and at least two of these species appear to be in decline. The magnitude of domestic dog impacts on native species in tropical areas like the Ecuadorian Andes currently are not recognized. Results of our study indicate that small and large carnivores are in urgent need of conservation and clearly point to dogs as a significant threat to a broad range of native species.

  8. Selection of astrophysical/astronomical/solar sites at the Argentina East Andes range taking into account atmospheric components

    Czech Academy of Sciences Publication Activity Database

    Piacentini, R.D.; García, B.; Micheletti, M.I.; Salum, G.; Freire, M.; Maya, J.; Mancilla, A.; Crinó, E.; Mandát, Dušan; Pech, M.; Bulik, T.

    2016-01-01

    Roč. 57, č. 12 (2016), s. 2559-2574 ISSN 0273-1177 R&D Projects: GA MŠk(CZ) 7AMB14AR005; GA MŠk LE13012; GA MŠk LG14019; GA MŠk LM2015046 Institutional support: RVO:68378271 Keywords : astrophysical * astronomical * solar: sites * Argentina -Andes: atmospheric components Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.401, year: 2016

  9. Diversity of bacteria producing pigmented colonies in aerosol, snow and soil samples from remote glacial areas (Antarctica, Alps and Andes)

    OpenAIRE

    González-Toril , E.; Amils , R.; Delmas , R. J.; Petit , J.-R.; Komárek , J.; Elster , J.

    2008-01-01

    Four different communities and one culture of pigmented microbial assemblages were obtained by incubation in mineral medium of samples collected from high elevation snow in the Alps (Mt. Blanc area) and the Andes (Nevado Illimani summit, Bolivia), from Antarctic aerosol (French station Dumont d'Urville) and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas). Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells be...

  10. Identificación, caracterización y dinámica de las geoformas glaciales y periglaciales en la Cordillera de los Andes a través de sensores remotos

    OpenAIRE

    Falaschi, Daniel

    2015-01-01

    El presente trabajo de Tesis Doctoral tuvo el objetivo de estudiar los glaciares y glaciares de escombros en tres regiones montañosas a lo largo de la Cordillera de los Andes Argentina: Monte San Lorenzo (Provincia de Santa Cruz), Volcán Domuyo (Provincia de Neuquén), y Nevados de Cachi (Provincia de Salta). Cada uno de estos sitios presenta características climáticas propias, representativas de tres porciones particulares de los Andes: Andes Patagónicos Meridionales, Andes Centrales Meridion...

  11. Ebola Virus

    Directory of Open Access Journals (Sweden)

    Anusha Rangare Lakshman

    2015-09-01

    Full Text Available The disease Ebola takes its name from the Ebola River situated near a village in the Democratic Republic of Congo, where the disease first appeared in 1976. It is caused by a virus from the Filoviridae family (filovirus. The present outbreak of Ebola Virus Disease (EVD concerns four countries in West Africa, namely Guinea, Liberia, Sierra Leone and Nigeria till date. Further to widespread transmission of the disease, it has been declared as a Public Health Emergency of International Concern by the World Health Organisation on 8 August 2014. As of 4 August 2014, countries have reported 1,711 cases (1,070 confirmed, 436 probable, 205 suspect, including 932 deaths. This review paper enlightens about the awareness of Ebola virus and its preventive measures. [Archives Medical Review Journal 2015; 24(3.000: 296-305

  12. Genome of Plant Maca (Lepidium meyenii) Illuminates Genomic Basis for High-Altitude Adaptation in the Central Andes.

    Science.gov (United States)

    Zhang, Jing; Tian, Yang; Yan, Liang; Zhang, Guanghui; Wang, Xiao; Zeng, Yan; Zhang, Jiajin; Ma, Xiao; Tan, Yuntao; Long, Ni; Wang, Yangzi; Ma, Yujin; He, Yuqi; Xue, Yu; Hao, Shumei; Yang, Shengchao; Wang, Wen; Zhang, Liangsheng; Dong, Yang; Chen, Wei; Sheng, Jun

    2016-07-06

    Maca (Lepidium meyenii Walp, 2n = 8x = 64), belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru (4000-4500 m). Considering that the rapid uplift of the central Andes occurred 5-10 million years ago (Ma), an evolutionary question arises regarding how plants such as maca acquire high-altitude adaptation within a short geological period. Here, we report the high-quality genome assembly of maca, in which two closely spaced maca-specific whole-genome duplications (WGDs; ∼6.7 Ma) were identified. Comparative genomic analysis between maca and closely related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway, and secondary metabolite biosynthesis via WGDs. The retention and subsequent functional divergence of many duplicated genes may account for the morphological and physiological changes (i.e., small leaf shape and self-fertility) in maca in a high-altitude environment. In addition, some duplicated maca genes were identified with functions in morphological adaptation (i.e., LEAF CURLING RESPONSIVENESS) and abiotic stress response (i.e., GLYCINE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION 2) under positive selection. Collectively, the maca genome provides useful information to understand the important roles of WGDs in the high-altitude adaptation of plants in the Andes. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Air temperature change in the northern and southern tropical Andes linked to North-Atlantic stadials and Greenland interstadials

    Science.gov (United States)

    Urrego, Dunia H.; Hooghiemstra, Henry

    2016-04-01

    We use eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the signature of millennial-scale climate variability during the last 30,000 years, in particular the Younger Dryas (YD), Heinrich stadials (HS) and Greenland interstadials (GI). We identify rapid responses of the vegetation to millennial-scale climate variability in the tropical Andes. The signature of HS and the YD are generally recorded as downslope migrations of the upper forest line (UFL), and are likely linked to air temperature cooling. The GI1 signal is overall comparable between northern and southern records and indicates upslope UFL migrations and warming in the tropical Andes. Our marker for lake level changes indicates a north to south difference that could be related to moisture availability. The direction of air temperature change recorded by the Andean vegetation is consistent with millennial-scale cryosphere and sea surface temperature records from the American tropics, but suggests a potential difference between the magnitude of temperature change in the ocean and the atmosphere.

  14. Spatio-Temporal Patterns of the 2010–2015 Extreme Hydrological Drought across the Central Andes, Argentina

    Directory of Open Access Journals (Sweden)

    Juan Antonio Rivera

    2017-08-01

    Full Text Available During the period 2010–2015, the semi-arid Central Andes in Argentina (CAA experienced one of the most severe and long-lasting hydrological droughts on record. Since the snowmelt is the most important source of water, the reduced snowfall over the mountains propagated the drought signal through the streamflows in the adjacent foothills east of the Andes ranges. Motivated by the widespread impacts on the socio-economic activities in the region, this study aims to characterize the recent hydrological drought in terms of streamflow deficits. Based on streamflow data from 20 basins, we used the standardized streamflow index (SSI to characterize hydrological droughts during the period 1971–2016. We found that the regional extent of the 2010–2015 hydrological drought was limited to the basins located north of 38° S, with mean duration of 67 months and maximum drought severity exhibiting a heterogeneous pattern in terms of spatial distribution and time of occurrence. The drought event reached extreme conditions in 14 of the 15 basins in the CAA, being record-breaking drought in six of the basins. This condition was likely driven by a cooling in the tropical Pacific Ocean resembling La Niña conditions, which generated a decrease in snowfall over the Andes due to suppressed frontal activity.

  15. ISOSTATICALLY DISTURBED TERRAIN OF NORTHWESTERN ANDES MOUNTAINS FROM SPECTRALLY CORRELATED FREE-AIR AND GRAVITY TERRAIN DATA

    Directory of Open Access Journals (Sweden)

    Hernández P Orlando

    2006-12-01

    Full Text Available Recently revised models on global tectonics describe the convergence of the North Andes, Nazca, Caribbean and South American Plates and their seismicity, volcanism, active faulting and extreme
    topography. The current plate boundaries of the area are mainly interpreted from volcanic and seismic datasets with variable confidence levels. New insights on the isostatic state and plate boundaries of
    the northwestern Andes Mountains can be obtained from the spectral analysis of recently available gravity and topography data.
    Isostatically disturbed terrain produces free-air anomalies that are highly correlated with the gravity effects of the terrain. The terrain gravity effects (TGE and free air gravity anomalies (FAGA of the
    Andes mountains spectral correlation data confirms that these mountains are isostatically disturbed. Strong negative terrain-correlated FAGA along western South America and the Greater and Lesser Antilles are consistent with anomalously deepened mantle displaced by subducting oceanic plates.

    Inversion of the compensated terrain gravity effects (CTGE reveals plate subduction systems with alternating shallower and steeper subduction angles. The gravity modeling highlights crustal
    deformation from plate collision and subduction and other constraints on the tectonism of the plate boundary zones for the region.

  16. Evidence of Teleconnections between the Peruvian central Andes and Northeast Brazil during extreme rainfall events

    Science.gov (United States)

    Sulca, J. C.; Vuille, M. F.; Silva, F. Y.; Takahashi, K.

    2013-12-01

    Knowledge about changes in regional circulation and physical processes associated with extreme rainfall events in South America is limited. Here we investigate such events over the Mantaro basin (MB) located at (10°S-13°S; 73°W-76°W) in the central Peruvian Andes and Northeastern Brazil (NEB), located at (9°S-15°S; 39°W-46°W). Occasional dry and wet spells can be observed in both areas during the austral summer season. The main goal of this study is to investigate potential teleconnections between extreme rainfall events in MB and NEB during austral summer. We define wet (dry) spells as periods that last for at least 3 (5) consecutive days with rainfall above (below) the 70 (30) percentile. To identify the dates of ocurrence of these events, we used daily accumulated rainfall data from 14 climate stations located in the Mantaro basin for the period 1965 to 2002. In NEB we defined a rainfall index which is based on average daily gridded rainfall data within the region for the same period. Dry (wet spells) in the MB are associated with positive (negative) OLR anomalies which extend over much of the tropical Andes, indicating the large-scale nature of these events. At 200 hPa anomalous easterly (westerly) zonal winds aloft accompany wet (dry) spells. Composite anomalies of dry spells in MB reveal significant contemporaneous precipitation anomalies of the opposite sign over NEB, which suggest that intraseasonal precipitation variability over the two regions may be dynamically linked. Indeed upper-tropospheric circulation anomalies over the central Andes extend across South America and appear to be tied to an adjustment in the Bolivian High-Nordeste Low system. Dry (wet) spells in NEB are equally associated with a large-scale pattern of positive (negative) OLR anomalies; however, there are no related significant OLR anomalies over the MB during these events. Dry (wet) spells are associated with robust patterns of anomalous wind fields at both low and upper

  17. Constraints on sediment transfer from the Andes to the coast of northern Chile

    Science.gov (United States)

    Binnie, Steven; Liermann, Ariane; Dunai, Tibor; Dewald, Alfred; Heinze, Stefan

    2013-04-01

    While rates of denudation have been suggested as having the potential to link tectonic processes with climate in many settings, the roles that sediment transport must also play have been largely neglected. It is the transport, or not, of eroded material, not necessarily the rate at which that material is produced which is the critical factor in many models of tectonic-climatic interactions. The notable lack of sediment in sections of the Peru-Chile trench has been implicated as a key control of subduction zone processes and consequently Andean mountain building, but little empirical data on sediment transport in the region exists. Here, we present the initial results of a study aiming to constrain the westward transfer of sediment from the Andes Mountains to the Pacific Coast of northern Chile by using in situ-produced cosmogenic nuclides. Fluvial sediments were collected at the mouths of several large catchments between 19° S and 26° S, where they drain into the Pacific, and also from upstream locations within each catchment. Sample sites were selected in order to investigate the cosmogenic nuclide derived basin-averaged denudation rates of the western flank of the Andes, and to compare this with the cosmogenic nuclide concentrations of fluvial sediments further downstream where the catchments exit to the coast. A simplistic interpretation of the cosmogenic 10Be concentrations as denudation rates gives results varying between ~10 and 300 m/Myr. We would expect the most rapid erosion to occur on the steeper, wetter western Andean flank and for slower erosion to be recorded from the more gentle sloping, hyperarid/arid regions between the foothills of the Andes and the Pacific coast. This pattern is observed in some basins but in others the nuclide concentrations imply the opposite, with several-fold higher erosion rates measured for the large catchments sampled at the coast in comparison to their mountainous Andean headwaters. One explanation for this unusual

  18. Factores de riesgo ambientales y alimentarios para la fluorosis dental, Andes, Antioquia, 2015

    Directory of Open Access Journals (Sweden)

    Gustavo A. Posada-Jaramillo

    2017-01-01

    Full Text Available Objetivo: determinar los factores ambientales y alimentarios asociados a la fluorosis dental en la población de 12 a 15 años del municipio de Andes en el año 2015, para generar propuestas de intervención en salud bucal. Metodología: estudio de casos y controles, con un control por caso. Con una población de 206 adolescentes de 12 a 15 años. Criterios de selección: adolescentes con diagnóstico de fluorosis dental entre 2012 y 2014, reportados al Sistema de Vigilancia Epidemiológica; se excluyeron aquellas personas que no tuvieran dientes erupcionados en más de un 50%, restauraciones amplias o caries extensas, dientes fracturados y edentulos totales. Los casos fueron seleccionados por muestreo aleatorio simple, los controles a conveniencia. Se realizó examen clínico para clasificar según el Índice de Dean la presencia y nivel de fluorosis dental, se aplicó encuesta a los padres para indagar sobre hábitos de autocuidado, e identificar posibles fuentes de exposición a flúor. Se analizaron variables sociodemográficas, alimentarias y comportamentales, ambientales y clínicas, se utilizaron Chi2 de Pearson – or con intervalos de confianza del 95%. Se efectúo análisis de contenido de concentración de flúor en muestras de agroquímicos, alimentos, agua de consumo humano, sal, cremas dentales y suelos. Resultados: mediante regresión logística binaria usando el método stepwise los resultados mostraron una asociación entre manipulación de agroquímicos y fluorosis dental (or = 2,093; 95% 1,017 y 4,307. Conclusión: la manipulación de agroquímicos es un factor de riesgo para la aparición de la fluorosis dental en los adolescentes del municipio de Andes.

  19. ENTERRANDO HERÓIS, PATRIARCAS, SUICIDAS E TRAIDORES: SOLIDARIEDADE E OSTRACISMO NOS ANDES COLOMBIANOS

    Directory of Open Access Journals (Sweden)

    Santiago Alvarez

    2001-10-01

    Full Text Available Este artigo discute diferenças e hierarquias encontradas nos ritos fúnebres de uma comunidade camponesa na região sudeste dos andes colombianos. Nessa comunidade - afetada por diferentes expressões de violência -, os funerais emergem como formas seletivas de manifestação de solidariedade social. De fato, na população analisada foram observadas notáveis diferenças quantitativas e qualitativas na organização e evolução de tais cerimônias fúnebres. As diferenças estão relacionadas ao sexo e à posição social do morto, bem como à forma pela qual ele ou ela morreu. Em um extremo das representações e práticas sociais relacionadas à morte encontram-se os enterros de homens jovens, mortos tragicamente. Estes são objeto de um culto particular, sendo glorificados pela comunidade. No outro extremo, a comunidade expressa sua rejeição às mulheres suicidas, rejeição que se coloca em evidência, especialmente, durante a evolução dos funerais.This article discusses the differences and hierarchies found in the funeral rites of a peasant community in the southwestern region of the Colombian Andes. In this community - affected by different expressions of violence - funerals emerge as selective forms for the manifestation of social solidarity. In the population considered, marked qualitative and quantitative differences in the organization and evolution of these funeral rites were, in fact, observed. The differences are related to the sex and social position of the deceased, as well as to the way in which he or she died. At one extreme of the social practices and representations associated with death are the burials of young men killed tragically. These are the object of a particular cult, and are glorified by the community. At the other extreme, the community expresses its rejection of women who have committed suicide, an attitude which is particularly evident during the course of the funeral.

  20. The role of climate in the accumulation of lithium-rich brine in the Central Andes

    International Nuclear Information System (INIS)

    Godfrey, L.V.; Chan, L.-H.; Alonso, R.N.; Lowenstein, T.K.; McDonough, W.F.; Houston, J.; Li, J.; Bobst, A.; Jordan, T.E.

    2013-01-01

    Highlights: • δ 7 Li of waters and rocks in the Central Andes were measured. • Halite/brine partition coefficients of lithium and δ 7 Li of halite were determined. • Li-rich brines have a high component of fluids of geothermal origin. • Removal of lithium by clays is minor relative to other regions of the world. • The weathering flux of lithium and sodium decouple according to climate state. - Abstract: Lithium-rich brine within the sub-surface of the Salar del Hombre Muerto (SHM) salt pan in the Andes of northwestern Argentina has a chemical and isotopic composition which is consistent with Li derived from several sources: the modern halite saturated lagoon, Li-rich salts and brines formed recently, and dissolution of halite which precipitated from ancient saline lakes. SHM lies in the closed basin that includes part of the massive Cerro Galán caldera which is drained by the Río los Patos, which is responsible for 90% of surface runoff into the salar. The low Li isotope composition, +3.4‰, of this river is consistent with significant contributions of geothermal spring water. As water drains through the volcaniclastic deposits which cover a large proportion of the basin, Li removal, as indicated by decreasing Li/Na, occurs but without significant isotope fractionation. This indicates a mechanism of surface sorption onto smectite or ferrihydrite rather than Li incorporation into octahedral structural sites of clays. These observations suggest that conditions in this high altitude desert have limited the dilution of hydrothermal spring water as well as the formation of clay minerals, which jointly have allowed the Li resource to accumulate rapidly. Changes in climate on a multi-millennial time scale, specifically in the hydrologic budget, have resulted in solute accumulation rates that have been variable through time, and decoupled Li and Na fluxes. Inflow to the salar under modern conditions has high Li/Na (7.9 × 10 −3 by wt) with δ 7 Li

  1. Impact of glaciations on the long-term erosion in Southern Patagonian Andes

    Science.gov (United States)

    Simon-Labric, Thibaud; Herman, Frederic; Baumgartner, Lukas; Shuster, David L.; Braun, Jean; Reiners, Pete W.; Valla, Pierre G.; Leuthold, Julien

    2014-05-01

    The Southern Patagonian Andes are an ideal setting to study the impact of Late-Cenozoic climate cooling and onset of glaciations impact on the erosional history of mountain belts. The lack of tectonic activity during the last ~12 Myr makes the denudation history mainly controlled by surface processes, not by tectonics. Moreover, the glaciations history of Patagonia shows the best-preserved records within the southern hemisphere (with the exception of Antarctica). Indeed, the dry climate on the leeward side of Patagonia and the presence of lava flows interbedded with glacial deposits has allowed an exceptional preservation of late Cenozoic moraines with precise dating using K-Ar analyses on lava flow. The chronology of moraines reveals a long history covering all the Quaternary, Pliocene, and up to the Upper Miocene. The early growth of large glaciers flowing on eastern foothills started at ~7-6 Myr, while the maximum ice-sheet extent dates from approximately 1.1 Myr. In order to quantify the erosion history of the Southern Patagonian Andes and compare it to the glaciations sediment record, we collected samples along an age-elevation profile for low-temperature thermochronology in the eastern side of the mountain belt (Torres del Paine massif). The (U-Th)/He age-elevation relationship shows a clear convex shape providing an apparent long-term exhumation rate of ~0.2 km/Myr followed by an exhumation rate increase at ~6 Myr. Preliminary results of 4He/3He thermochronometry for a subset of samples complete the erosion history for the Plio-Pleistocene epoch. We used inverse procedure predicting 4He distributions within an apatite grain using a radiation-damage and annealing model to quantify He-diffusion kinetics in apatite. The model also allows quantifying the impact of potential U-Th zonation throughout each apatite crystal. Inversion results reveal a denudation history composed by a pulse of denudation at ~6 Ma, as suggested by the age-elevation relationship

  2. Changes in Andes snow cover from MODIS data, 2000–2016

    Directory of Open Access Journals (Sweden)

    F. A. Saavedra

    2018-03-01

    Full Text Available The Andes span a length of 7000 km and are important for sustaining regional water supplies. Snow variability across this region has not been studied in detail due to sparse and unevenly distributed instrumental climate data. We calculated snow persistence (SP as the fraction of time with snow cover for each year between 2000 and 2016 from Moderate Resolution Imaging Spectroradiometer (MODIS satellite sensors (500 m, 8-day maximum snow cover extent. This analysis is conducted between 8 and 36° S due to high frequency of cloud (>  30 % of the time south and north of this range. We ran Mann–Kendall and Theil–Sens analyses to identify areas with significant changes in SP and snowline (the line at lower elevation where SP  =  20 %. We evaluated how these trends relate to temperature and precipitation from Modern-Era Retrospective Analysis for Research and Applications-2 (MERRA2 and University of Delaware datasets and climate indices as El Niño–Southern Oscillation (ENSO, Southern Annular Mode (SAM, and Pacific Decadal Oscillation (PDO. Areas north of 29° S have limited snow cover, and few trends in snow persistence were detected. A large area (34 370 km2 with persistent snow cover between 29 and 36° S experienced a significant loss of snow cover (2–5 fewer days of snow year−1. Snow loss was more pronounced (62 % of the area with significant trends on the east side of the Andes. We also found a significant increase in the elevation of the snowline at 10–30 m year−1 south of 29–30° S. Decreasing SP correlates with decreasing precipitation and increasing temperature, and the magnitudes of these correlations vary with latitude and elevation. ENSO climate indices better predicted SP conditions north of 31° S, whereas the SAM better predicted SP south of 31° S.

  3. Contrasting Climate Change Impact on River Flow from Glacierised Catchments in the Himalayan and Andes Mountains

    Science.gov (United States)

    Pellicciotti, F.; Ragettli, S.; Immerzeel, W. W. W.

    2016-12-01

    Glaciers and glacierised catchments in mountainous regions react to a changing climate in different manners depending on climate and glacier characteristics. Despite the key role of mountain ranges as natural water towers, their hydrological balance and future changes in glacier runoff associated with climate warming remain poorly understood because of high meteorological variability, physical inaccessibility and the complex interplay between climate, cryosphere and hydrological processes. We use a state-of-the art glacio-hydrological model informed by data from high altitude observations and the latest CMIP5 climate change scenarios to quantify the climate change impact on glaciers and runoff for two contrasting catchments vulnerable to changes in the cryosphere. The two catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites are projected to experience a strong decrease in glacier area, they show remarkably different hydrological responses. Icemelt is on a rising limb in Langtang at least until 2041-2050 and starts to decrease afterwards, while in Juncal icemelt was already beyond its tipping point at the beginning of the 21st century. This contrasting response can be explained by differences in the elevation distribution of the glaciers in the two regions. In Juncal, many glaciers are melting up to the highest elevations already during the reference period (2000-2010) and increasing melt rates due to higher air temperatures cannot compensate the loss of glacier area. In Langtang, large sections of the glaciers at high elevations are currently not exposed to melt, but will be in the future, thus compensating for the loss of glacier area at lower elevations. As a result of these changes and projected changes in precipitation, in Juncal runoff will sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In Langtang, future water

  4. Classification of debris-covered glaciers and rock glaciers in the Andes of central Chile

    Science.gov (United States)

    Janke, Jason R.; Bellisario, Antonio C.; Ferrando, Francisco A.

    2015-07-01

    In the Dry Andes of Chile (17 to 35° S), debris-covered glaciers and rock glaciers are differentiated from true glaciers based on the percentage of surface debris cover, thickness of surface debris, and ice content. Internal ice is preserved by an insulating cover of thick debris, which acts as a storage reservoir to release water during the summer and early fall. These landforms are more numerous than glaciers in the central Andes; however, the existing legislation only recognizes uncovered or semicovered glaciers as a water resource. Glaciers, debris-covered glaciers, and rock glaciers are being altered or removed by mining operations to extract valuable minerals from the mountains. In addition, agricultural expansion and population growth in this region have placed additional demands on water resources. In a warmer climate, as glaciers recede and seasonal water availability becomes condensed over the course of a snowmelt season, rock glaciers and debris-covered glaciers contribute a larger component of base flow to rivers and streams. As a result, identifying and locating these features to implement sustainable regional planning for water resources is important. The objective of this study is to develop a classification system to identify debris-covered glaciers and rock glaciers based on the interpretation of satellite imagery and aerial photographs. The classification system is linked to field observations and measurements of ice content. Debris-covered glaciers have three subclasses: surface coverage of semi (class 1) and fully covered (class 2) glaciers differentiates the first two forms, whereas debris thickness is critical for class 3 when glaciers become buried with more than 3 m of surface debris. Based on field observations, the amount of ice decreases from more than 85%, to 65-85%, to 45-65% for semi, fully, and buried debris-covered glaciers, respectively. Rock glaciers are characterized by three stages. Class 4 rock glaciers have pronounced

  5. Methane fluxes from a wet puna ecosystem in the Peruvian Andes

    Science.gov (United States)

    Jones, Sam; Diem, Torsten; Priscila Huaraca Quispe, Lidia; Quispe Ccahuana, Adan Julian; Meir, Patrick; Arn Teh, Yit

    2014-05-01

    Discrepancies exist between top-down and bottom-up estimates of the tropical South American atmospheric methane budget. This suggests that current source-sink inventories fail to adequately characterise the landscapes of the region. This may be particularly true of Andean environments where very few field observations have been made. The high tropical Andes, between tree and permanent snow-lines, is home to diverse grass, shrub and giant rosette dominated ecosystems known variously from Venezuela to northern Chile and Argentina as paramo, jalca and puna. In humid regions these are characterised by wet, organic-rich mineral soils, peat-forming wetlands and shallow lakes. Such conditions are likely to promote methane production and potentially represent a regionally significant source to the atmosphere that should be considered. We report on methane fluxes from a bunch-grass dominated puna habitat at 3500 m above sea level in south-eastern Peru. Mean annual temperature and precipitation are 11 °C and 2500 mm, respectively. Temperature is aseasonal but experiences considerable diurnal variations with overnight frosting common-place. In contrast, rainfall is intensely episodic and has a pronounced wet season between September and March. Sampling encompassed a range of topographic features, such as grassland on freely draining, gently inclined or steep slopes and depressions containing bogs, over a 3 ha ridge to basin transition. Monthly sampling was carried out between January 2011 and June 2013 to investigate seasonal variability in methane fluxes. Intensive sampling campaigns were conducted to investigate spatial and short-term variations on a daily basis in two nine-day campaigns during wet and dry season. The site was a net source of methane to the atmosphere during the period of study. Methane fluxes were dominated by emissions from bogs, whereas, freely draining grassland exhibited weak source or marginal sink activity. Temporal variations were most notable at

  6. Tectonostratigraphic reconstruction Cretaceous volcano-sedimentary in the northwestern Andes: from extensional tectonics to arc accretion.

    Science.gov (United States)

    Zapata, S.; Patino, A. M.; Cardona, A.; Mejia, D.; Leon, S.; Jaramillo, J. S.; Valencia, V.; Parra, M.; Hincapie, S.

    2014-12-01

    Active continental margins characterized by continuous convergence experienced overimposed tectonic configurations that allowed the formation of volcanic arcs, back arc basins, transtensional divergent tectonics or the accretion of exotic volcanic terranes. Such record, particularly the extensional phases, can be partially destroyed and obscure by multiple deformational events, the accretion of exotic terranes and strike slip fragmentation along the margin. The tectonic evolution of the northern Andes during the Mesozoic is the result of post Pangea extension followed by the installation of a long-lived Jurassic volcanic arc (209 - 136 ma) that apparently stops between 136 Ma and 110 Ma. The Quebradagrande Complex has been define as a single Lower Cretaceous volcano-sedimentary unit exposed in the western flank of the Central Cordillera of the Colombian Andes that growth after the Late Jurassic to Early Cretaceous magmatic hiatus. The origin of this unit have been related either to an oceanic volcanic arc or a marginal basin environment. The existence of such contrasting models reflect the regional perspective followed in published studies and the paucity of detail analysis of the volcano-sedimentary sequences.We integrate multiple approaches including structural mapping, stratigraphy, geochemistry, U-Pb provenance and geochronology to improve the understanding of this unit and track the earlier phases of accumulation that are mask on the overimposed tectonic history. Our preliminary results suggest the existence of different volcano-sedimentary units that accumulated between 100 Ma and 82 Ma.The older Lower Cretaceous sequences was deposited over Triassic metamorphic continental crust and include a upward basin deepening record characterized by thick fan delta conglomerates, followed by distal turbidites and a syn-sedimentary volcanic record at 100 ma. The other sequence include a 85 - 82 Ma fringing arc that was also formed close to the continental margin or

  7. Different Phases of Earthquake Cycle Reflected in GPS Measured Crustal Deformations along the Andes

    Science.gov (United States)

    Khazaradze, G.; Klotz, J.

    2001-12-01

    The South American Geodynamic Activities (SAGA) project was initiated in 1993 by the GeoForschungsZentrum together with host organizations in Argentina and Chile with the main objective of studying the kinematics and dynamics of present-day deformation processes along the central and southern Andes. Currently the SAGA network consists of 230 geodetic markers spanning more than 2000 km long distance from Peru/Chile border in the north to Cape Horn in the south. The majority of the observed crustal deformation field is relatively homogenous: roughly parallel to the plate convergence direction and decreasing in magnitude away from the deformation front. This pattern is characteristic for the \\textit{inter-seismic} phase of earthquake deformation cycle and can be explained by the elastic strain accumulation due to locking of the thrust interface between the subducting Nazca and the overriding South America plates. However, in addition to the dominant inter-seismic signal, close examination of the observed velocity field also reveals significant spatial and temporal variations, contrary to the commonly used assumption of constant deformation rates. This variation is especially pronounced for the measurements in the vicinity of the 1995 Mw8.0 Antofagasta earthquake (22{° }S-26{° }S). Here, after capturing up to 1 meters of \\textit{co-seismic} displacements associated with this event, the analysis of data obtained during the three following field campaigns (1996-1999), reveals highly time dependent deformation pattern. This can be explained by the decreasing importance of \\textit{post-seismic} effects of the Antofagasta event relative to the increasing dominance of the inter-seismic phase of subduction. Perhaps, even more interesting time dependent observations have been detected in the southern part the SAGA network (38{° }S-43{° }S).Here, after 35 years of the occurrence of the 1960 Mw9.5 Chile earthquake, we still see the continuing post-seismic effects of this

  8. Las ignimbritas del complejo volcánico Coranzuli (Puna Argentina-Andes Centrales

    Directory of Open Access Journals (Sweden)

    Martí, J.

    1987-12-01

    Full Text Available The Coranzulí is a large Upper Miocene volcanic complex located on a NE-SW and NW-SE regional faults intersection, at 66º 15' W 23º S, in the Northwest of Argentina in Jujuy province. It corresponds to one of four large volcanic complexes which represent the end of Transversal Volcanic Chaines in La Puna Argentina in the Central Andes. The volcanic activity was characterized by at least four separate ignimbrite eruptions which produced four different ignimbrite sheets. These are well welded, very crystal-rich, lithie poor ignimbrites and have a moderate to high pumice content. The total volume of the Coranzuli ignimbrites exeededs 650 Km3. Preliminary data indicate that the eruption oeeurred from a homogeneous magmatic chamber without zoning. The emplacement characteristics of the ignimbrites and the lack of basal or interbedded plinian fall deposits suggest that the eruptions developed quickly to massive proportions.El Coranzuli es uno de los grandes complejos volcánicos que representan el remate final de las Cadenas Volcánicas Transversales de la Puna Argentina, en los Andes Centrales. Se trata de un complejo volcánico del Mioceno superior situado a los 66º 15' W 23º S en el NW de Argentina en la provincia de Jujuy, en la intersección entre dos fallas regionales de dirección NE-SW y NW-SE, respectivamente. La actividad eruptiva se caracterizó por la existencia de, al menos, cuatro erupciones ignimbríticas que produjeron cuatro diferentes mantos ignimbríticos. Se trata de ignimbritas bien soldadas, muy ricas en cristales, pobre en fragmentos líticos y que presentan un contenido en fragmentos pumíticos de moderado a alto. El volumen total que representan estas ignimbritas supera los 650 km3. Los datos preliminares indican que el magma juvenil deriva de una cámara magmática homogénea no zonada. Las características de emplazamiento de estas ignimbritas, así como la falta de depósitos plinianos de caída en la base o

  9. Aridity changes in the temperate-Mediterranean transition of the Andes since ad 1346 reconstructed from tree-rings

    Energy Technology Data Exchange (ETDEWEB)

    Christie, Duncan A.; Quesne, Carlos le [Universidad Austral de Chile, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Boninsegna, Jose A.; Morales, Mariano S.; Villalba, Ricardo [Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales, IANIGLA, Departamento de Dendrocronologia e Historia Ambiental, Mendoza (Argentina); Cleaveland, Malcolm K.; Stahle, David W. [University of Arkansas Fayetteville, Tree-Ring Laboratory, Department of Geosciences, Fayetteville, AR (United States); Lara, Antonio [Universidad Austral de Chile, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Universidad Austral de Chile, Forest Ecosystem Services under Climatic Fluctuations (Forecos), Valdivia (Chile); Mudelsee, Manfred [Climate Risk Analysis, Hanover (Germany); Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany)

    2011-04-15

    The Andes Cordillera acts as regional ''Water Towers'' for several countries and encompasses a wide range of ecosystems and climates. Several hydroclimatic changes have been described for portions of the Andes during recent years, including glacier retreat, negative precipitation trends, an elevation rise in the 0 isotherm, and changes in regional streamflow regimes. The Temperate-Mediterranean transition (TMT) zone of the Andes (35.5 -39.5 S) is particularly at risk to climate change because it is a biodiversity hotspot with heavy human population pressure on water resources. In this paper we utilize a new tree-ring network of Austrocedrus chilensis to reconstruct past variations in regional moisture in the TMT of the Andes by means of the Palmer Drought Severity Index (PDSI). The reconstruction covers the past 657 years and captures interannual to decadal scales of variability in late spring-early summer PDSI. These changes are related to the north-south oscillations in moisture conditions between the Mediterranean and Temperate climates of the Andes as a consequence of the latitudinal position of the storm tracks forced by large-scale circulation modes. Kernel estimation of occurrence rates reveals an unprecedented increment of severe and extreme drought events during the last century in the context of the previous six centuries. Moisture conditions in our study region are linked to tropical and high-latitude ocean-atmospheric forcing, with PDSI positively related to Nino-3.4 SST during spring and strongly negatively correlated with the Antarctic Oscillation (AAO) during summer. Geopotential anomaly maps at 500-hPa show that extreme dry years are tightly associated with negative height anomalies in the Ross-Amundsen Seas, in concordance with the strong negative relationship between PDSI and AAO. The twentieth century increase in extreme drought events in the TMT may not be related to ENSO but to the positive AAO trend during late-spring and

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

    Science.gov (United States)

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

    2011-12-01

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

  11. SARS virus

    Indian Academy of Sciences (India)

    ... consequence.Protein spike similar. HE gene absent. 2787 nucleotides. Largest genome. Jumps species by genetic deletion. < 300 compounds screened. Glycyrrhizin (liquorics/mullatha) seems attractive. Antivirals not effective. Vaccines – animal model only in monkeys. Killed corona or knockout weakened virus as targets.

  12. Poder y sociedad en los Andes: Manuel Isidoro Belzu, un caudillo popular. Bolivia, 1848-1855

    Directory of Open Access Journals (Sweden)

    Luis Javier Ortíz Mesa

    1995-01-01

    Full Text Available En este ensayo quiero referirme a un gobernante boliviano, Manuel Isidoro Belzu, presidente entre los años de 1848 y 1855. Con una larga carrera militar de casi 25 años, en un ambiente de permanente inestabilidad política y con una fascinante estrategia, Belzu ha sido percibido por algunos historiadores y literatos como un «Caudillo del Pueblo», otros lo calificaron como un demagogo y algunos más como el presidente para la Bolivia de entonces. Manuel Isidoro Belzu nació al tiempo que se vislumbraba la Bolivia Republicana en 1808. Fue un hombre pobre como muchos de sus conciudadanos, predominantemente indígenas. No obstante, Belzu fue un mestizo, expresión de los cambios raciales que desde la Colonia se produjeron en la población de la Audiencia de Charcas cuya sede y capital fue Chuquisaca o Sucre, donde tuvo asiento el emporio minero más importante y productivo de los Andes, el Cerro Rico de Potosí.

  13. Caracterización de semillas de lupino (Lupinus mutabilis sembrado en los Andes de Colombia

    Directory of Open Access Journals (Sweden)

    Ortega-David Eduar

    2010-03-01

    Full Text Available En este trabajo se identificaron las propiedades físicas, composicionales y fisicoquímicas de la semilla de Lupino (Lupinus mutabilis cultivado en Nariño (Andes de Colombia. Su composición se determinó realizando análisis proximales de semilla completa, tegumento y cotiledones. Además se determinó el contenido de minerales y su composición elemental. Se estableció cuantitativamente el contenido de alcaloides presentes y su perfil composicional. Se determinaron propiedades físicas como la forma y el tamaño de la semilla. Se determinaron las propiedades fisicoquímicas como la capacidad de retención de agua y el pH. Las cantidades de nutrientes de la semilla son menores que los valores reportados en la literatura. Se presenta una variación en cuanto al perfil de alcaloides, siendo la esparteína la segunda sustancia de mayor presencia. La hidratación de la semilla conduce a un incremento de 1.72 veces su tamaño original. Se puede sugerir que la proteína posee afinidad hidrofílica evidenciada por la elevada capacidad de retención de agua de la semilla. La identificación de estas propiedades permite reconocer el potencial de la semilla para su futuro aprovechamiento.

  14. Tectonic geomorphology of large normal faults bounding the Cuzco rift basin within the southern Peruvian Andes

    Science.gov (United States)

    Byers, C.; Mann, P.

    2015-12-01

    The Cuzco basin forms a 80-wide, relatively flat valley within the High Andes of southern Peru. This larger basin includes the regional capital of Cuzco and the Urubamba Valley, or "Sacred Valley of the Incas" favored by the Incas for its mild climate and broader expanses of less rugged and arable land. The valley is bounded on its northern edge by a 100-km-long and 10-km-wide zone of down-to-the-south systems of normal faults that separate the lower area of the down-dropped plateau of central Peru and the more elevated area of the Eastern Cordillera foldbelt that overthrusts the Amazon lowlands to the east. Previous workers have shown that the normal faults are dipslip with up to 600 m of measured displacements, reflect north-south extension, and have Holocene displacments with some linked to destructive, historical earthquakes. We have constructed topographic and structural cross sections across the entire area to demonstrate the normal fault on a the plateau peneplain. The footwall of the Eastern Cordillera, capped by snowcapped peaks in excess of 6 km, tilts a peneplain surface northward while the hanging wall of the Cuzco basin is radially arched. Erosion is accelerated along the trend of the normal fault zone. As the normal fault zone changes its strike from east-west to more more northwest-southeast, normal displacement decreases and is replaced by a left-lateral strike-slip component.

  15. Agriculture at the Edge: Landscape Variability of Soil C Stocks and Fluxes in the Tropical Andes

    Science.gov (United States)

    Riveros-Iregui, D. A.; Peña, C.

    2015-12-01

    Paramos, or tropical alpine grasslands occurring right above the forest tree-line (2,800 - 4,700 m), are among the most transformed landscapes in the humid tropics. In the Tropical Andes, Paramos form an archipelago-like pattern from Northern Colombia to Central Peru that effectively captures atmospheric moisture originated in the Amazon-Orinoco basins, while marking the highest altitude capable of sustaining vegetation growth (i.e., 'the edge'). This study investigates the role of land management on mediating soil carbon stocks and fluxes in Paramo ecosystems of the Eastern Cordillera of Colombia. Observations were collected at a Paramo site strongly modified by land use change, including active potato plantations, pasture, tillage, and land abandonment. Results show that undisturbed Paramos soils have high total organic carbon (TOC), high soil water content (SWC), and low soil CO2 efflux (RS) rates. However, Paramo soils that experience human intervention show lower TOC, higher and more variable RS rates, and lower SWC. This study demonstrates that changes in land use in Paramos affect differentially the accumulation and exchange of soil carbon with the atmosphere and offers implications for management and protection strategies of what has been deemed the fastest evolving biodiversity ecosystem in the world.

  16. Conservationist Systems, one environmental alternative for the agriculture of the Northeastern Andes of Colombia

    International Nuclear Information System (INIS)

    Villamizar Moreno, J.

    1999-01-01

    The article shows the results of a proposal of alternative handling of the agriculture ecosystem tobacco-bean-maize, main agricultural activity of the Northeastern Andes of Colombia. This system is the base of the economic and alimentary security and the main factor of degradation of the natural resources of the region. The work looks for to develop the diversified rotations, as essential component of biological diversity, the reduced works as strategy of protection of the soil and the promotion of the agriculture ecology like new model of agricultural development. The results of the work show that the high volume of organic residuals coming from the rotation tobacco bean maize, become compost in the field and the reduction of the farm, they promote the stability of the productive components of the soils and their agricultural yields. The biggest levels of organic matter and of total porosity, generated by the biggest biological activity, they indicate that the technological alternatives of the proposal slow the effects of the degradation originated by the conventional agriculture. These alternatives can be included in the regional programs of agricultural production, like solution principle and as strategy for the sustainable development of the region

  17. Correlation of Early Tertiary Terrestrial Deposits of the Amaga Basin, Cauca Depression, Colombian Andes

    Science.gov (United States)

    Sierra, G. M.; Sierra, G. M.; MacDonald, W. D.

    2001-05-01

    The Amaga Formation of the Amaga Basin preserves early Tertiary terrestrial deposits of many facies: channel, crevasse splay, paludal, flood plain, point bar, etc. These deposits lie between two major strike-slip fault zones, the Cauca and the Romeral in the Cauca Valley of the northern Andes of Colombia. Coal deposits characterize the lower part of the stratigraphic section; fine to medium clastic sediments otherwise dominate the sections. Within the basin, correlation between sections is difficult because various discontinuities interrupt the continuity of the strata. These include Tertiary intrusives, folding and faulting. Rapid lateral facies changes further complicate the correlations. Detailed studies on five stratigraphic sections are underway. Multiple methods of correlating sections are being used, including fluvial sequence stratigraphy in outcrops, architectural facies analysis, heavy mineral separates, grain-size and grain-ratio variations, paleocurrent directions, and magnetic property variations. Distinctive regional variations in magnetic anisotropic susceptibility indicate areas in which tectonic effects overprint sedimentary fabrics. The presence of secondary hematite and siderite is related to that overprinting. A major compositional break (identified by grain-ratio variations) has been found in the middle of the section. The integrated correlation results are summarized.

  18. Estimates of Carbon Reservoirs in High-Altitude Wetlands in the Colombian Andes

    Directory of Open Access Journals (Sweden)

    Enrique Javier Peña

    2009-10-01

    Full Text Available The observed increase in emission of greenhouse gases, with attendant effects on global warming, have raised interests in identifying sources and sinks of carbon in the environment. Terrestrial carbon (C sequestration involves capture of atmospheric C through photosynthesis and storage in biota, soil and wetlands. Particularly, wetland systems function primarily as long-term reservoirs for atmospheric carbon dioxide (CO2 and as sources of atmospheric methane (CH4. The objective of this study was to evaluate the patterns of carbon reservoirs in two high-altitude wetlands in the central Andean mountain of Colombia. Carbon cycle in both systems is related mainly with the plant biomass dynamics from the littoral zone. Thus, total organic carbon concentrate an average up to 329 kg of N ha-1 and 125 kg of P ha-1 every year vs only 17 kg N ha-1 and 6 kg P ha-1 in the water column of the limnetic zone in the wetland, evidencing spatial differences in carbon concentrations for these types of ecosystems. Results revealed that these systems participate in the balance and sequestration of carbon in the Colombian Andes.

  19. A phytosociological analysis and synopsis of the dry woodlands and succulent vegetation of the Peruvian Andes

    Directory of Open Access Journals (Sweden)

    ANTONIO GALÁN-DE-MERA

    2016-01-01

    Full Text Available ABSTRACT A phytosociological approach to dry forest and cactus communities on the occidental slopes of the Peruvian Andes is presented in base of 164 plots carried out following the Braun-Blanquet method. From them, 52 have been made recently, and the other 112 were taken from the literature. After a multivariate analysis, using a hierarchical clustering and a detendred correspondence analysis, the Acacio-Prosopidetea class (dry forest and cactus communities, developed on soils with some edaphic humidity or precipitations derived from El Niño Current, the Opuntietea sphaericae class (cactus communities of central and southern Peru, on few stabilized rocky or sandy soils and the Carico-Caesalpinietea class (dry forests of the Peruvian coastal desert, influenced by the maritime humidity of the cold Humboldt Current, are differentiated. Within the Acacio-Prosopidetea class, two alliances are commented: the Bursero-Prosopidion pallidae (with two new associations Loxopterygio huasanginis-Neoraimondietum arequipensis and Crotono ruiziani-Acacietum macracanthae, and the new alliance Baccharido-Jacarandion acutifoliae (with the new associations Armatocereo balsasensis-Cercidietum praecocis and Diplopterydo leiocarpae-Acacietum macracanthae. For the Opuntietea sphaericae class, the association Haageocereo versicoloris-Armatocereetum proceri (Espostoo-Neoraimondion is described on the basis of plots from hyperarid localities of central Peru. Finally, a typological classification of the studied plant communities is given.

  20. Determinants of School Performance Among Quechua Children in the Peruvian Andes

    Science.gov (United States)

    Jacoby, Enrique; Cueto, Santiago; Pollitt, Ernesto

    1999-01-01

    In the rural Andes of Peru, primary school inefficiency ranks higher than in the rest of the country, with a nearly 50 per cent rate of first grade repetition. In 1993 the investigators administered a battery of four psycho-educational tests to 360 schoolchildren in the fourth and fifth grades at ten primary schools in the Andean region of Huaraz. They also recorded the children's individual characteristics, i.e. family background, nutritional status, and educational attainment, and rated the schools according to educational features such as classroom size, time devoted to learning, and student-teacher ratio. A year later, in 1994, children were re-examined in the schools using the same test battery. All subjects were small for their age, had poor diets, spoke mostly Quechua at home (Spanish in school), lived in a rural environment, and walked considerable distances to school. Regression analyses of the 1993 data indicated that the performance of Quechua children on verbal tests was heavily influenced by family background, while their mathematical competence was related to school experience. On the other hand, improvement in test scores from one year to the next appeared to be strongly related to test performance in 1993 and less clearly to the other recorded variables. Finally, the schools' promotion rates were clearly associated with test scores from the previous year but less clearly with grade repetition rates.

  1. Millennial-scale climate variability during the Last Glacial period in the tropical Andes

    Science.gov (United States)

    Fritz, S. C.; Baker, P. A.; Ekdahl, E.; Seltzer, G. O.; Stevens, L. R.

    2010-04-01

    Millennial-scale climate variation during the Last Glacial period is evident in many locations worldwide, but it is unclear if such variation occurred in the interior of tropical South America, and, if so, how the low-latitude variation was related to its high-latitude counterpart. A high-resolution record, derived from the deep drilling of sediments on the floor of Lake Titicaca in the southern tropical Andes, is presented that shows clear evidence of millennial-scale climate variation between ˜60 and 20 ka BP. This variation is manifested by alternations of two interbedded sedimentary units. The two units have distinctive sedimentary, geochemical, and paleobiotic properties that are controlled by the relative abundance of terrigenous or nearshore components versus pelagic components. The sediments of more terrigenous or nearshore nature likely were deposited during regionally wetter climates when river transport of water and sediment was higher, whereas the sediments of more pelagic character were deposited during somewhat drier climates regionally. The majority of the wet periods inferred from the Lake Titicaca sediment record are correlated with the cold events in the Greenland ice cores and North Atlantic sediment cores, indicating that increased intensity of the South American summer monsoon was part of near-global scale climate excursions.

  2. Paleohidrología de los últimos 25000 años en los Andes bolivianos

    Directory of Open Access Journals (Sweden)

    1995-01-01

    Full Text Available PALÉOHYDROLOGIE DES DERNIÈRES 25 000 ANNÉES DANS LES ANDES BOLIVIENNES. Nous présentons une reconstruction climatique de haute résolution de l’Altiplano bolivien (Andes Centrales basée sur des données géomorphologiques, sédimentologiques, palynologiques et provenant de l’analyse des faunes d’ostracodes. Nous avons déterminé (1, de manière semi-quantitative, la température ainsi que (2 de façon quantitative, les variations des niveaux lacustres depuis la fin du Pléistocène (25 000 ans BP. Les principaux résultats obtenus sont les suivants: de 25 000 à 18 000 ans BP, les températures atmosphériques sont basses ainsi que les niveaux des lacs entre 18 000 et 15 000/14 000 ans BP, la présence d’une lacune de sédimentation est indicatrice d’une phase climatique sèche pendant le Tardi-Glaciaire (15 000/14 000 - 10 500, les lacs (phase Tauca et les glaciers se sont étendus de 10 500 à 8000 ans BP, les lacs et les glaciers reculent très rapidement pendant que la température globale moyenne augmente à l’Holocène moyen (8 000-3 900 ans BP, le climat régional est globalement de type sec autour de 3900 ans BP, le niveau du lac Titicaca monte fortement des conditions relativement humides s’installent alors et se maintiennent par la suite pendant le Petit âge de la Glace (16ème-19ème siècles, des conditions froides et humides prévalent. En base a datos geomorfológicos, sedimentológicos, palinológicos y el análisis de fauna de ostrácodos, se ha determinado (1, de manera semicuantitativa, la temperatura así como (2 los cambios cuantificados de las variaciones de los niveles lacustres desde el final del Pleistoceno (25 000 años BP. Los principales resultados obtenidos son los siguientes: de 25 000 a 18 000 años BP, las temperaturas atmosféricas son bajas así como los niveles de los lagos entre 18 000 y 15 000/14 000 años BP, una fase climática seca es definida por la presencia de una laguna de sedimentaci

  3. Changes of glaciers in the Andes of Chile and priorities for future work.

    Science.gov (United States)

    Pellicciotti, F; Ragettli, S; Carenzo, M; McPhee, J

    2014-09-15

    Glaciers in the Andes of Chile seem to be shrinking and possibly loosing mass, but the number and types of studies conducted, constrained mainly by data availability, are not sufficient to provide a synopsis of glacier changes for the past or future or explain in an explicit way causes of the observed changes. In this paper, we provide a systematic review of changes in glaciers for the entire country, followed by a discussion of the studies that have provided evidence of such changes. We identify a missing type of work in distributed, physically-oriented modelling studies that are needed to bridge the gap between the numerous remote sensing studies and the specific, point scale works focused on process understanding. We use an advanced mass balance model applied to one of the best monitored glaciers in the region to investigate four main research issues that should be addressed in modelling studies for a sound assessment of glacier changes: 1) the use of physically-based models of glacier ablation (energy balance models) versus more empirical models (enhanced temperature index approaches); 2) the importance of the correct extrapolation of air temperature forcing on glaciers and in high elevation areas and the large uncertainty in model outputs associated with it; 3) the role played by snow gravitational redistribution; and 4) the uncertainty associated with future climate scenarios. We quantify differences in model outputs associated with each of these choices, and conclude with suggestions for future work directions. © 2013 Elsevier B.V. All rights reserved.

  4. Leaf Litterfall and Decomposition of Polylepis reticulata in the Treeline of the Ecuadorian Andes

    Directory of Open Access Journals (Sweden)

    Juan Pinos

    2017-02-01

    Full Text Available Leaf litterfall contributes significantly to carbon fluxes in forests. A crucial open question for the sustainability of mountain forests is how climate change will affect this and other carbon fluxes (eg photosynthesis and respiration. Leaf litterfall and decomposition of Polylepis reticulata, an endemic species of the Andes, were analyzed during a period of 1 year at 6 experimental plots located in the Andean páramo between 3700 and 3900 m above sea level in Cajas National Park, Ecuador. Litterfall was collected in each plot using 5 randomly distributed traps. Every trap had a 40-cm diameter (0.125 m2 and was suspended 0.8 to 1.0 m above the ground. The decomposition rate of the leaf litter was analyzed using litter bags. Eighteen bags with approximately 20 g of dry litter were placed in the litter layer in each experimental plot and collected 30, 60, 90, 150, 210, 300, and 365 days after they were installed. The mean annual litterfall recorded was 3.77 Mg ha−1, representing 51% of the leaf biomass present in the canopy, so the leaf life span of P. reticulata in Cajas National Park is 1.98 years. Litterfall occurred all year, with no significant seasonal pattern. The mean decomposition rate (k obtained for this study period was 0.38 year−1. This study contributes to the information gap on litterfall and decomposition in natural forests located at the highest elevations in the world.

  5. Effects of loadingeunloading and wettingedrying cycles on geomechanical behaviors of mudrocks in the Colombian Andes

    Institute of Scientific and Technical Information of China (English)

    Mario Camilo Torres-Suarez; Adolfo Alarcon-Guzman; Rafael Berdugo-De Moya

    2014-01-01

    The mudrocks in the Colombian Andes, particularly those exhibiting low cementation (bonding), are susceptible to degradation when the environmental conditions change, which are challenging issues for engineering works. In this paper, the changes in physico-mechanical properties of mudrocks were moni-tored in laboratory, and some influential factors on the mechanical competence of geomaterials were studied. The geotechnical characteristics and experimental designs were developed from physical, chem-ical, mechanical and compositional points of view. In the tests, the techniques such as vapor equilibrium technique (VET) were employed to apply wettingedrying cycles and to control relative humidity (suction-controlled) and loadingeunloading cycles through ultrasonic wave velocities technique. The results show that the main failure mechanisms for the laminated mudrocks start on the microscopic scale by fissures coalescence, exhibiting physico-chemical degradation as well;the global geomechanical behavior presents a state between a ductile, like rock, and a fragile, like soil. The obtained results can provide engineering values according to monitoring laboratory set, when compared with in situ conditions.

  6. A phytosociological analysis and synopsis of the dry woodlands and succulent vegetation of the Peruvian Andes.

    Science.gov (United States)

    Galán-DE-Mera, Antonio; Sánchez-Vega, Isidoro; Linares-Perea, Eliana; Campos, José; Montoya, Juan; Vicente-Orellana, José A

    2016-01-01

    A phytosociological approach to dry forest and cactus communities on the occidental slopes of the Peruvian Andes is presented in base of 164 plots carried out following the Braun-Blanquet method. From them, 52 have been made recently, and the other 112 were taken from the literature. After a multivariate analysis, using a hierarchical clustering and a detendred correspondence analysis, the Acacio-Prosopidetea class (dry forest and cactus communities, developed on soils with some edaphic humidity or precipitations derived from El Niño Current), the Opuntietea sphaericae class (cactus communities of central and southern Peru, on few stabilized rocky or sandy soils) and the Carico-Caesalpinietea class (dry forests of the Peruvian coastal desert, influenced by the maritime humidity of the cold Humboldt Current), are differentiated. Within the Acacio-Prosopidetea class, two alliances are commented: the Bursero-Prosopidion pallidae (with two new associations Loxopterygio huasanginis-Neoraimondietum arequipensis and Crotono ruiziani-Acacietum macracanthae), and the new alliance Baccharido-Jacarandion acutifoliae (with the new associations Armatocereo balsasensis-Cercidietum praecocis and Diplopterydo leiocarpae-Acacietum macracanthae). For the Opuntietea sphaericae class, the association Haageocereo versicoloris-Armatocereetum proceri (Espostoo-Neoraimondion) is described on the basis of plots from hyperarid localities of central Peru. Finally, a typological classification of the studied plant communities is given.

  7. Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago

    Science.gov (United States)

    Eichler, A.; Gramlich, G.; Kellerhals, T.; Tobler, L.; Rehren, Th.; Schwikowski, M.

    2017-01-01

    The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

  8. Does External Funding Help Adaptation? Evidence from Community-Based Water Management in the Colombian Andes

    Science.gov (United States)

    Murtinho, Felipe; Eakin, Hallie; López-Carr, David; Hayes, Tanya M.

    2013-11-01

    Despite debate regarding whether, and in what form, communities need external support for adaptation to environmental change, few studies have examined how external funding impacts adaptation decisions in rural resource-dependent communities. In this article, we use quantitative and qualitative methods to assess how different funding sources influence the initiative to adapt to water scarcity in the Colombian Andes. We compare efforts to adapt to water scarcity in 111 rural Andean communities with varied dependence on external funding for water management activities. Findings suggest that despite efforts to use their own internal resources, communities often need external support to finance adaptation strategies. However, not all external financial support positively impacts a community’s abilities to adapt. Results show the importance of community-driven requests for external support. In cases where external support was unsolicited, the results show a decline, or “crowding-out,” in community efforts to adapt. In contrast, in cases where communities initiated the request for external support to fund their own projects, findings show that external intervention is more likely to enhance or “crowds-in” community-driven adaptation.

  9. Multidecadal change in streamflow associated with anthropogenic disturbances in the tropical Andes

    Science.gov (United States)

    Molina, A.; Vanacker, V.; Brisson, E.; Mora, D.; Balthazar, V.

    2015-10-01

    Andean headwater catchments are an important source of freshwater for downstream water users. However, few long-term studies exist on the relative importance of climate change and direct anthropogenic perturbations on flow regimes in these catchments. In this paper, we assess change in streamflow based on long time series of hydrometeorological data (1974-2008) and land cover reconstructions (1963-2009) in the Pangor catchment (282 km2) located in the tropical Andes. Three main land cover change trajectories can be distinguished during the period 1963-2009: (1) expansion of agricultural land by an area equal to 14 % of the catchment area (or 39 km2) in 46 years' time, (2) deforestation of native forests by 11 % (or -31 km2) corresponding to a mean rate of 67 ha yr-1, and (3) afforestation with exotic species in recent years by about 5 % (or 15 km2). Over the time period 1963-2009, about 50 % of the 64 km2 of native forests was cleared and converted to agricultural land. Given the strong temporal variability of precipitation and streamflow data related to El Niño-Southern Oscillation, we use empirical mode decomposition techniques to detrend the time series. The long-term increasing trend in rainfall is remarkably different from the observed changes in streamflow, which exhibit a decreasing trend. Hence, observed changes in streamflow are not the result of long-term change in precipitation but very likely result from anthropogenic disturbances associated with land cover change.

  10. Hungry earth and vengeful stars: soul loss and identity in the Peruvian Andes.

    Science.gov (United States)

    Greenway, C

    1998-10-01

    This article contributes to the cross-cultural literature on fright sickness and soul loss with an analysis of cases among Quechua indians (runa) in a rural community in the southern Peruvian Andes. One of the aims of this article is to incorporate an emic understanding of the intersection of the cosmological and social landscapes into discussions of Quechua conceptions of health and illness. It outlines Quechua constructions of body, self, and cosmos that are relevant to explaining the concepts of soul/spirit, interior/exterior, and runa/nonruna that are related to soul loss. The illness suffered by victims of fright sickness embodies the Quechua construction of self and is linked not only to broader sociopolitical realities of Peru but also to cosmological beliefs. The diagnosis of spirit loss and fright in this cultural context reveals a crisis of identity: sufferers represent nonruna, or nonhumans. They succumb to fright or soul loss because of an emic concept of vulnerability that transcends the characteristics of gender and age usually associated with soul loss cross-culturally. Treatments, therefore, involve a reaffirmation of ethnic identity and a reintegration of patients into their families in terms of a culturally specific understanding of identity, community, and cosmos. rights reserved

  11. High-resolution dynamic downscaling of CMIP5 output over the Tropical Andes

    Science.gov (United States)

    Reichler, Thomas; Andrade, Marcos; Ohara, Noriaki

    2015-04-01

    Our project is targeted towards making robust predictions of future changes in climate over the tropical part of the South American Andes. This goal is challenging, since tropical lowlands, steep mountains, and snow covered subarctic surfaces meet over relatively short distances, leading to distinct climate regimes within the same domain and pronounced spatial gradients in virtually every climate quantity. We use an innovative approach to solve this problem, including several quadruple nested versions of WRF, a systematic validation strategy to find the version of WRF that best fits our study region, spatial resolutions at the kilometer scale, 20-year-long simulation periods, and bias-corrected output from various CMIP5 simulations that also include the multi-model mean of all CMIP5 models. We show that the simulated changes in climate are consistent with the results from the global climate models and also consistent with two different versions of WRF. We also discuss the expected changes in snow and ice, derived from off-line coupling the regional simulations to a carefully calibrated snow and ice model.

  12. Methodology for Evaluating the Quality of Ecosystem Maps: A Case Study in the Andes

    Directory of Open Access Journals (Sweden)

    Dolors Armenteras

    2016-08-01

    Full Text Available Uncertainty in thematic maps has been tested mainly in maps with discrete or fuzzy classifications based on spectral data. However, many ecosystem maps in tropical countries consist of discrete polygons containing information on various ecosystem properties such as vegetation cover, soil, climate, geomorphology and biodiversity. The combination of these properties into one class leads to error. We propose a probability-based sampling design with two domains, multiple stages, and stratification with selection of primary sampling units (PSUs proportional to the richness of strata present. Validation is undertaken through field visits and fine resolution remote sensing data. A pilot site in the center of the Colombian Andes was chosen to validate a government official ecosystem map. Twenty primary sampling units (PSUs of 10 × 15 km were selected, and the final numbers of final sampling units (FSUs were 76 for the terrestrial domain and 46 for the aquatic domain. Our results showed a confidence level of 95%, with the accuracy in the terrestrial domain varying between 51.8% and 64.3% and in the aquatic domain varying between 75% and 92%. Governments need to account for uncertainty since they rely on the quality of these maps to make decisions and guide policies.

  13. Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago.

    Science.gov (United States)

    Eichler, A; Gramlich, G; Kellerhals, T; Tobler, L; Rehren, Th; Schwikowski, M

    2017-01-31

    The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

  14. Low temperature resistance in saplings and ramets of Polylepis sericea in the Venezuelan Andes

    Science.gov (United States)

    Rada, Fermín; García-Núñez, Carlos; Rangel, Sairo

    2009-09-01

    The frequent occurrence of all year-round below zero temperatures in tropical high mountains constitutes a most stressful climatic factor that plants have to confront. Polylepis forests are found well above the continuous forest line and are distributed throughout the Andean range. These trees require particular traits to overcome functional limitations imposed on them at such altitudes. Considering seedling and sapling stages as filter phases in stressful environments, some functional aspects of the regeneration of Polylepis sericea, a species associated to rock outcrops in the Venezuelan Andes, were studied. We characterized microclimatic conditions within a forest, in a forest gap and surrounding open páramo and determined low temperature resistance mechanisms in seedlings, saplings and ramets. Conditions in the forest understory were more stable compared to the forest gaps and open surrounding páramo. Minimum temperatures close to the ground were 3.6 °C lower in the open páramo compared to the forest understory. Maximum temperatures were 9.0 °C higher in the open páramo. Ice nucleation and injury temperatures occurred between -6 and -8 °C for both ramets and saplings, an evidence of frost avoidance to low nighttime temperatures. In this particular forest, this resistance ability is determinant in their island-like distribution in very specific less severe temperature habitats.

  15. PABLO PALACIO: LA VIOLENCIA CORPORAL SOBRE LAS IDENTIDADES IMPOSIBLES EN LA ZONA DE LOS ANDES

    Directory of Open Access Journals (Sweden)

    Diego Falconí Travez

    2014-10-01

    Full Text Available Pablo Palacio, escritor ecuatoriano de la segunda década del siglo pasado, se encargó de construir en sus relatos un catálogo de cuerpos raros con sexualidades ambiguas e inquietantes que se alejan del canon andino al que él pertenece. No obstante, una de las cuestiones que más llama la atención es que varios de esos cuerpos son disciplinados por ciertos discursos de poder de un modo violento. Este trabajo explora desde la teoría literaria dichas vejaciones tomando en consideración la violencia sobre las identidades de mujeres y homosexuales en dos de sus relatos, e indaga sobre cuestiones como la economía de la representación, la  violencia, su relación con el texto literario y la vulnerabilidad, como requisito sine qua non de las vejaciones, en ciertos cuerpos en la zona de los Andes.

  16. Influenza (Flu) Viruses

    Science.gov (United States)

    ... Types Seasonal Avian Swine Variant Pandemic Other Influenza (Flu) Viruses Language: English (US) Español Recommend on Facebook ... influenza circulate and cause illness. More Information about Flu Viruses Types of Influenza Viruses Influenza A and ...

  17. Zika Virus and Pregnancy

    Medline Plus

    Full Text Available ... Management Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus ... Patient Education Pamphlets - Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your ...

  18. Zika Virus and Pregnancy

    Medline Plus

    Full Text Available ... Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and ... Education Pamphlets - Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your fetus ...

  19. Zika Virus and Pregnancy

    Science.gov (United States)

    ... Management Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and ... Patient Education Pamphlets - Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your fetus ...

  20. Zika Virus and Pregnancy

    Medline Plus

    Full Text Available ... Management Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and ... Patient Education Pamphlets - Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your fetus ...

  1. Zika Virus and Pregnancy

    Medline Plus

    Full Text Available ... Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and Pregnancy Page ... Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your fetus if you ...

  2. Computer Viruses: An Overview.

    Science.gov (United States)

    Marmion, Dan

    1990-01-01

    Discusses the early history and current proliferation of computer viruses that occur on Macintosh and DOS personal computers, mentions virus detection programs, and offers suggestions for how libraries can protect themselves and their users from damage by computer viruses. (LRW)

  3. De Los ríos profundos a Lituma en los andes: La respuesta de Mario Vargas Llosa a José María Arguedas

    Directory of Open Access Journals (Sweden)

    Marie-Madeleine Gladieu

    2011-05-01

    Full Text Available La novela de Mario Vargas Llosa Lituma en los Andes1 poco tiene que ver, aparentemente, con el mundo narrativo de José María Arguedas: las nuevas aventuras de un personaje ficticio bien conocido de los lectores, presente en varias obras anteriores de aquel autor, en nada se asemejan a las del niño Ernesto ni a las de otro protagonista arguediano. Los Andes sirven de decorado para los dos relatos, pero entre la naturaleza y los pueblos que se suceden en Los ríos profundos2en toda su diversidad, y los paisajes hoscos y siempre peligrosos por los que cruza Lituma, apenas reconoce el lector aquella parte del sur peruano. Algunos detalles, sin embargo, al examinar bien el texto y el contexto de Lituma en los Andes, llaman la atención.

  4. Dengue virus receptor

    OpenAIRE

    Hidari, Kazuya I.P.J.; Suzuki, Takashi

    2011-01-01

    Dengue virus is an arthropod-borne virus transmitted by Aedes mosquitoes. Dengue virus causes fever and hemorrhagic disorders in humans and non-human primates. Direct interaction of the virus introduced by a mosquito bite with host receptor molecule(s) is crucial for virus propagation and the pathological progression of dengue diseases. Therefore, elucidation of the molecular mechanisms underlying the interaction between dengue virus and its receptor(s) in both humans and mosquitoes is essent...

  5. Computer Virus and Trends

    OpenAIRE

    Tutut Handayani; Soenarto Usna,Drs.MMSI

    2004-01-01

    Since its appearance the first time in the mid-1980s, computer virus has invited various controversies that still lasts to this day. Along with the development of computer systems technology, viruses komputerpun find new ways to spread itself through a variety of existing communications media. This paper discusses about some things related to computer viruses, namely: the definition and history of computer viruses; the basics of computer viruses; state of computer viruses at this time; and ...

  6. Coupled geohazards at Southern Andes (Copahue-Lanín volcanoes): Chile's GEO supersite proposal

    Science.gov (United States)

    Lara, Luis E.; Cordova, Loreto

    2017-04-01

    Southern Andes are a young and active mountain belt where volcanism and tectonic processes (and those related to the hydrometeorological conditions controlled by this geological setting) pose a significant threat to the growing communities nearby. This proposal focus on a ca. 200 km long segment of the Southern Andes where 9 stratovolcanoes and 2 distributed volcanic fields are located, just along a tectonic corridor defined by the northern segment of the Liquiñe-Ofqui Faul System (LOFS), a long-lived active strike-slip fault running for 1200 km. Volcanoes in this area take part of the central province of the Andean Southern Volcanic Zone (37-41°S), particularly the northermost portion that is limited at the south by an Andean tranverse fault (Lanalhue Fault, which define the Villarrica-Lanin volcanic chain) and run along the horse-tail array of the LOFS to the north. Most of the stravolcanoes are atop of the LOFS main branch with only 3 exceptions (Callaqui, Tolhuaca and Lanín) 15-20 km away, but related to transverse faults. Hazards in the segment derive from the activity of some of the most active volcanoes in South America (e.g., Villarrica, Llaima), others with long-lasting weak activity (e.g., Copahue) or some volcanoes with low frequency but high magnitude eruptions in the geological record. Only since the beggining of the 20th century 80 eruptions have been recorded in this area. In addition, activity of the LOFS has been detected prior to some eruptions and coeval with some others (e.g., Lonquimay 1989). A strong two-way coupling between tectonics and volcanism has been proposed for the segment but only recently detected by geophysical techniques or numerical modelling. Tectonic triggered landslides are frequent in this region together with debris flows at erupting ice-covered volcanoes or stream headed at high altitude basins. The latter scenario seems to be worst at present because of global climate change. Ground-based monitoring networks for both

  7. La Cordillera de los Andes: presentación de los problemas geomorfológicos

    Directory of Open Access Journals (Sweden)

    1974-01-01

    Full Text Available Le soulèvement en voussoir ponto-pliocène a donné aux Andes leur volume montagneux actuel. Il a porté à plus de 4000 m des surfaces d'érosion élaborées au cours du Tertiaire et, pour la surface dite de la 'puna', principalement au cours du Miocène. Cependant, ces surfaces sont très généralement polygéniques et polycycliques. Elles sont dominées par de grandes cordillères orientées qui sont le plus souvent des horsts signalant les secteurs de surrection maximale. Certains horsts sont encore actifs comme celui de la Cordillère Blanche au Pérou. Ces surfaces sont déformées tant sur les bordures des bassins intérieurs que sur les flancs de la montagne ou elles sont disséquées et réduites à l'état de lanières. Elles ont pu disparaître par suite du recoupement vers le haut des versants des grandes vallées, notamment aux extrémités de la chaîne, là ou les Andes sont plus étroites. En contrebas, des aplanissements se développent au Pliocène et même au Quaternaire ancien dans des secteurs relativement stables: ainsi des glacis d'érosion tronquent des séries plissées au Pliocène sur l'Altiplano péruvo-bolivien et des surfaces d'abrasion sont retouchées en glacis sur les bourrelets côtiers péruvo-chiliens. Il convient de faire la distinction entre les surfaces qui recoupent les séries plissées en roche dure (calcaires, grès, rhyolites, etc. et dont la durée d'élaboration a été longue, et les glacis qui recoupent ou retouchent des volumes tendres (pélites, cinérites, conglomérats, à élaboration rapide. Les grandes vallées sont, les unes, adaptées aux grandes directions structurales consécutives aux mouvements de la fin du Tertiaire (l'adaptation d'ensemble s'accompagne souvent de nombreuses inadaptations locales, les autres suivent les anciennes directions structurales antérieures au soulèvement. Le Quaternaire se marque par une succession de périodes froides, accompagnées de glaciations dans

  8. Near-surface temperature lapse rates in a mountainous catchment in the Chilean Andes

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    Ayala; Schauwecker, S.; Pellicciotti, F.; McPhee, J. P.

    2011-12-01

    In mountainous areas, and in the Chilean Andes in particular, the irregular and sparse distribution of recording stations resolves insufficiently the variability of climatic factors such as precipitation, temperature and relative humidity. Assumptions about air temperature variability in space and time have a strong effect on the performance of hydrologic models that represent snow processes such as accumulation and ablation. These processes have large diurnal variations, and assumptions that average over longer time periods (days, weeks or months) may reduce the predictive capacity of these models under different climatic conditions from those for which they were calibrated. They also introduce large uncertainties when such models are used to predict processes with strong subdiurnal variability such as snowmelt dynamics. In many applications and modeling exercises, temperature is assumed to decrease linearly with elevation, using the free-air moist adiabatic lapse rate (MALR: 0.0065°C/m). Little evidence is provided for this assumption, however, and recent studies have shown that use of lapse rates that are uniform in space and constant in time is not appropriate. To explore the validity of this approach, near-surface (2 m) lapse rates were calculated and analyzed at different temporal resolution, based on a new data set of spatially distributed temperature sensors setup in a high elevation catchment of the dry Andes of Central Chile (approx. 33°S). Five minutes temperature data were collected between January 2011 and April 2011 in the Ojos de Agua catchment, using two Automatic Weather Stations (AWSs) and 13 T-loggers (Hobo H8 Pro Temp with external data logger), ranging in altitude from 2230 to 3590 m.s.l.. The entire catchment was snow free during our experiment. We use this unique data set to understand the main controls over temperature variability in time and space, and test whether lapse rates can be used to describe the spatial variations of air

  9. Da Amazônia ao Pacífico cruzando os Andes

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    Enrique Amayo Zevallos

    1993-04-01

    Full Text Available A Área Amazônica (AA é compartilhada por oito países sul-americanos independentes. Desde os tempos coloniais sentiu-se a necessidade da construção de uma via de união da AA com o Oceano Pacífico. Mas os Andes, em termos técnicos e econômicos, foram barreira insuperável até as últimas décadas do século XIX. Nos últimos anos, para o Brasil - país que tem perto de 60% da AA -, esta via vem se tornando cada vez mais importante em termos de exportação, especialmente para o mercado japonês, de grãos, madeira, polpa de madeira etc., ao mesmo tempo em que o Japão também deseja acesso direto à AA. Brasil e Peru, segundo país da AA, com a maior e mais ocidental costa no Pacífico, têm desenvolvido projetos para a construção de uma estrada, contando para isso com apoio financeiro oferecido pelo Japão em diversas oportunidades. Tais projetos tentam conciliar não apenas os interesses de Brasil e Peru, mas também os da Bolívia, país mediterrâneo que poderia finalmente ter acesso livre à costa do Pacífico. Os Estados Unidos, porém, opõem-se a construção da mencionada via e, o projeto está a espera de que o financiamento anteriormente aventado permita sua concretização. Parece que, na construção da projetada estrada, interesses estratégicos das grandes potências mundiais estão envolvidos.The Amazon Area (AA is shared by 8 independent south american countries. Since colonial times it was felt the need of a road linking the AA to the Pacific Ocean. Up to the last decades of the 19th Century the Andes were, in technical and economical terms, almost an insuperable challenge. In the last years for Brazil, the country that has about 60% of the AA, that road has become almost a need for exporting grains, timber, woodpulp etc. (mainly to Japan. And Japan also wants an acess to that area. So, Brasil, together with Peru - the second, after Brazil, AA country that has the largest and westernmost coast in the Pacific - have

  10. Weathering as the limiting factor of denudation in the Western escarpment of the Andes

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    Abbühl, L. M.; Schlunegger, F.; Kracht, O.; Ramseyer, K.; Rieke-Zapp, D.; Aldahan, A.; von Blanckenburg, F.

    2009-04-01

    A crucial issue in process geomorphology is the search for the scale and the extent to which precipitation, and climate in general, influences the nature and the rates of sediment transfer (weathering, erosion, sediment transport and deposition). We present an analysis of the possible interplay between precipitation, weathering and denudation rates for the western Andean slope between the Cordillera and the Pacific coast. It is based on morphometric studies and quantitative 10Be denudation rate estimates of three transverse river systems (Piura at 5°S, Pisco at 13°S, and Lluta at 18°S) draining the Western escarpment of the Peruvian and North Chilean Andes. The systems originate at elevations >3000 m above sea level, cover an area between 3000 and 10'000 km2 and discharge into the Pacific Ocean. The precipitation rate pattern implies a hyperarid climate at the coast, and semi-arid to semi-humid conditions in the Cordillera where the streams rise. There, climatic conditions are generally controlled by the easterlies that deliver moisture from the Atlantic Ocean via the low level Andean jet. The precipitation rate pattern of the Cordillera shows a North-South decreasing trend, from ca. 1000 mm/yr in Northern Peru to 150 mm/yr in Northern Chile. In these higher regions of the drainage basins, hillslopes are convex with nearly constant curvatures and are mantled by a >1 m thick regolith cover. In addition, hillslope erosion is limited to the regolith-bedrock interface. We interpret these geomorphic features to indicate weathering-controlled sediment discharge. In the lower river segments, beyond tectonic knickzones, regular precipitation is almost absent. For the case of the Piura river in Northern Peru, precipitation in this segment occurs in relation to highly episodic El Niño events related to the westerlies. This results in a supply-limited sediment discharge, leading to predominance of channelized processes on the hillslopes, a spare regolith cover and an

  11. Extreme hydrometeorological events in the Peruvian Central Andes during austral summer and their relationship with the large-scale circulation

    Science.gov (United States)

    Sulca, Juan C.

    In this Master's dissertation, atmospheric circulation patterns associated with extreme hydrometeorological events in the Mantaro Basin, Peruvian Central Andes, and their teleconnections during the austral summer (December-January-February-March) are addressed. Extreme rainfall events in the Mantaro basin are related to variations of the large-scale circulation as indicated by the changing strength of the Bolivian High-Nordeste Low (BH-NL) system. Dry (wet) spells are associated with a weakening (strengthening) of the BH-NL system and reduced (enhanced) influx of moist air from the lowlands to the east due to strengthened westerly (easterly) wind anomalies at mid- and upper-tropospheric levels. At the same time extreme rainfall events of the opposite sign occur over northeastern Brazil (NEB) due to enhanced (inhibited) convective activity in conjunction with a strengthened (weakened) Nordeste Low. Cold episodes in the Mantaro Basin are grouped in three types: weak, strong and extraordinary cold episodes. Weak and strong cold episodes in the MB are mainly associated with a weakening of the BH-NL system due to tropical-extratropical interactions. Both types of cold episodes are associated with westerly wind anomalies at mid- and upper-tropospheric levels aloft the Peruvian Central Andes, which inhibit the influx of humid air masses from the lowlands to the east and hence limit the potential for development of convective cloud cover. The resulting clear sky conditions cause nighttime temperatures to drop, leading to cold extremes below the 10-percentile. Extraordinary cold episodes in the MB are associated with cold and dry polar air advection at all tropospheric levels toward the central Peruvian Andes. Therefore, weak and strong cold episodes in the MB appear to be caused by radiative cooling associated with reduced cloudiness, rather than cold air advection, while the latter plays an important role for extraordinary cold episodes only.

  12. Diversity of bacteria producing pigmented colonies in aerosol, snow and soil samples from remote glacial areas (Antarctica, Alps and Andes)

    Science.gov (United States)

    González-Toril, E.; Amils, R.; Delmas, R. J.; Petit, J.-R.; Komárek, J.; Elster, J.

    2008-04-01

    Four different communities and one culture of pigmented microbial assemblages were obtained by incubation in mineral medium of samples collected from high elevation snow in the Alps (Mt. Blanc area) and the Andes (Nevado Illimani summit, Bolivia), from Antarctic aerosol (French station Dumont d'Urville) and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas). Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells belong to the Bacteria domain. The phylogenetic comparison with the currently available rDNA database allowed the identification of sequences belonging to Proteobacteria (Alpha-, Beta- and Gamma-proteobacteria), Actinobacteria and Bacteroidetes phyla. The Andes snow culture was the richest in bacterial diversity (eight microorganisms identified) and the maritime Antarctic soil the poorest (only one). Snow samples from Col du midi (Alps) and the Andes shared the highest number of identified microorganisms (Agrobacterium, Limnobacter, Aquiflexus and two uncultured Alphaproteobacteria clones). These two sampling sites also shared four sequences with the Antarctic aerosol sample (Limnobacter, Pseudonocardia and an uncultured Alphaproteobacteria clone). The only microorganism identified in the maritime Antarctica soil (Brevundimonas sp.) was also detected in the Antarctic aerosol. The two snow samples from the Alps only shared one common microorganism. Most of the identified microorganisms have been detected previously in cold environments (Dietzia kujamenisi, Pseudonocardia Antarctica, Hydrogenophaga palleronii and Brebundimonas sp.), marine sediments (Aquiflexus balticus, Pseudomonas pseudoalkaligenes, Pseudomonas sp. and one uncultured Alphaproteobacteria), and soils and rocks (Pseudonocardia sp., Agrobactrium sp., Limnobacter sp. and two uncultured Alphaproteobacetria clones). Air current dispersal is the best model to explain the presence of very specific microorganisms, like those

  13. Compositional data supports decentralized model of production and circulation of artifacts in the pre-Columbian south-central Andes.

    Science.gov (United States)

    Lazzari, Marisa; Pereyra Domingorena, Lucas; Stoner, Wesley D; Scattolin, María Cristina; Korstanje, María Alejandra; Glascock, Michael D

    2017-05-16

    The circulation and exchange of goods and resources at various scales have long been considered central to the understanding of complex societies, and the Andes have provided a fertile ground for investigating this process. However, long-standing archaeological emphasis on typological analysis, although helpful to hypothesize the direction of contacts, has left important aspects of ancient exchange open to speculation. To improve understanding of ancient exchange practices and their potential role in structuring alliances, we examine material exchanges in northwest Argentina (part of the south-central Andes) during 400 BC to AD 1000 (part of the regional Formative Period), with a multianalytical approach (petrography, instrumental neutron activation analysis, laser ablation inductively coupled plasma mass spectrometry) to artifacts previously studied separately. We assess the standard centralized model of interaction vs. a decentralized model through the largest provenance database available to date in the region. The results show: ( i ) intervalley heterogeneity of clays and fabrics for ordinary wares; ( ii ) intervalley homogeneity of clays and fabrics for a wide range of decorated wares (e.g., painted Ciénaga); ( iii ) selective circulation of two distinct polychrome wares (Vaquerías and Condorhuasi); ( iv ) generalized access to obsidian from one major source and various minor sources; and ( v ) selective circulation of volcanic rock tools from a single source. These trends reflect the multiple and conflicting demands experienced by people in small-scale societies, which may be difficult to capitalize by aspiring elites. The study undermines centralized narratives of exchange for this period, offering a new platform for understanding ancient exchange based on actual material transfers, both in the Andes and beyond.

  14. Ilustración arqueológica en los Andes (1850-1890

    Directory of Open Access Journals (Sweden)

    Joanne Pillsbury

    Full Text Available Resumen En términos generales, es posible trazar en las publicaciones europeas sobre los Andes una trayectoria histórica en el curso de cuatro siglos, desde un sistema de representación que está íntimamente atado – y afiliado – a la palabra escrita, a uno donde las imágenes se convierten en la razón de ser de la publicación. Esta trayectoria refleja el campo de la arqueología en sí mismo, desde sus orígenes en una tradición de anticuarios dominada por las preocupaciones filológicas durante los siglos XVI y XVII, al siglo XIX, donde las evidencias fotográficas ganan fuerza frente a las escritas. Este documento se centra en el pico de esta trayectoria: los atlas arqueológicos creados entre 1850 y 1890, en particular el trabajo de Wilhelm Reiss y Alphons Stübel y su publicación en tres volúmenes titulada “The necropolis of Ancon in Peru” (“La necrópolis de Ancón en el Perú”. El presente estudio analiza el papel de la ilustración arqueológica en la iluminación, la difusión y comprensión de un pasado pre-inca durante el siglo XIX, y en última instancia, cómo las imágenes dan forma a la construcción del conocimiento.

  15. Volcanic tremor and local earthquakes at Copahue volcanic complex, Southern Andes, Argentina

    Science.gov (United States)

    Ibáñez, J. M.; Del Pezzo, E.; Bengoa, C.; Caselli, A.; Badi, G.; Almendros, J.

    2008-07-01

    In the present paper we describe the results of a seismic field survey carried out at Copahue Volcano, Southern Andes, Argentina, using a small-aperture, dense seismic antenna. Copahue Volcano is an active volcano that exhibited a few phreatic eruptions in the last 20 years. The aim of this experiment was to record and classify the background seismic activity of this volcanic area, and locate the sources of local earthquakes and volcanic tremor. Data consist of several volcano-tectonic (VT) earthquakes, and many samples of back-ground seismic noise. We use both ordinary spectral, and multi-spectral techniques to measure the spectral content, and an array technique [Zero Lag Cross Correlation technique] to measure the back-azimuth and apparent slowness of the signals propagating across the array. We locate VT earthquakes using a procedure based on the estimate of slowness vector components and S-P time. VT events are located mainly along the border of the Caviahue caldera lake, positioned at the South-East of Copahue volcano, in a depth interval of 1-3 km below the surface. The background noise shows the presence of many transients with high correlation among the array stations in the frequency band centered at 2.5 Hz. These transients are superimposed to an uncorrelated background seismic signal. Array solutions for these transients show a predominant slowness vector pointing to the exploited geothermal field of "Las Maquinitas" and "Copahue Village", located about 6 km north of the array site. We interpret this coherent signal as a tremor generated by the activity of the geothermal field.

  16. Test of an Hypothesis of Magnetization, Tilt and Flow in an Hypabyssal Intrusion, Colombian Andes

    Science.gov (United States)

    Muggleton, S.; MacDonald, W. D.; Estrada, J. J.; Sierra, G. M.

    2002-05-01

    Magnetic remanence in the Miocene Clavijo intrusion in the Cauca Valley, adjacent to the Cordillera Central, plunges steeply northward (MacDonald et al., 1996). Assuming magnetization in a normal magnetic field, the expected remanence direction is approximately I= 10o, D= 000o; the observed remanence is I=84o, D=003o. The discrepancy could be explained by a 74o rotation about a horizontal E-W axis, i.e., about an axis normal to the nearby N-S trending Romeral fault zone. If the intrusion is the shallow feeder of a now-eroded andesitic volcano, then perhaps the paleovertical direction is preserved in flow lineations and provides a test of the tilt/rotation of the remanence. In combination, the steep remanence direction, vertical flow, and the inferred rotation of the volcanic neck lead to the hypothesis of a shallow-plunging southward lineation for this body. Using anisotropy of magnetic susceptibility (AMS) as a proxy for the flow lineation, it is predicted that the K1 (maximum susceptibility) axis in this body plunges gently south. This hypothesis was tested using approximately 50 oriented cores from 5 sites near the west margin of the Clavijo intrusion. The results suggest a NW plunging lineation, inconsistent with the initial hypothesis. However, a relatively consistent flow lineation is suggested by the K1 axes. If this flow axis represents paleovertical, it suggests moderate tilting of the Clavijo body towards the southeast. The results are encouraging enough to suggest that AMS may be useful for determining paleo-vertical in shallow volcanic necks and hypabyssal intrusions, and might ultimately be useful in a tilt-correction for such bodies. Other implications of the results will be discussed. MacDonald, WD, Estrada, JJ, Sierra, GM, Gonzalez, H, 1996, Late Cenozoic tectonics and paleomagnetism of North Cauca Basin intrusions, Colombian Andes: Dual rotation modes: Tectonophysics, v 261, p. 277-289.

  17. Between hearth and labor market: the recruitment of peasant women in the Andes.

    Science.gov (United States)

    Radcliffe, S A

    1990-01-01

    To cover subsistence requirements, peasant women from the Peruvian Andes increasingly are being forced to engage in income-generating activities, including domestic service, marketing, manufacturing, and herding. In many cases, recruitment into waged labor involves migration from rural communities. Case studies of the placement of peasant women in external labor markets illustrate the complex micro- and macro-level factors that determine the mix of productive and reproductive labor. The sexual division of labor in the domestic economy and community is the critical in regulating the length of absence of peasant women from the home, the types of jobs taken, and the migratory destination. In 1 such case study, 56 women from the village of Kallarayan (all of whom had migrated at some point) were interviewed during 13 months of fieldwork in 1984-85. There is no paid employment in Kallarayan, so 14% of the village's population is involved in migration to urban areas or commercial agricultural areas in jungle valleys at any point. Male migration is high in the 11-40-year age group, but becomes seasonal once men marry. Female migrants tend to remain away from the village for longer periods, but are almost exclusively single. Recruitment of peasant women into paid labor is achieved by 5 types of agents: family, godparents and friends, authority figures, recruiting agents, and employers. Peasant girls under 15 years of age tend to be allocated to external labor markets (largely domestic services) by parents and godparents; after 15 years, however, when children are considered to reach adulthood, there is a shift toward self-motivated migration or recruitment by employers and agents. The eldest daughter typically enters migration at age 14 years and sacrifices her education, while younger siblings remain in the home longer. In all but the poorest families, female migration for waged labor ends with marriage.

  18. An analysis of surface air temperature trends and variability along the Andes

    Science.gov (United States)

    Franquist, Eric S.

    Climate change is difficult to study in mountainous regions such as the Andes since steep changes in elevation cannot always be resolved by climate models. However, it is important to examine temperature trends in this region as rises in surface air temperature are leading to the melting of tropical glaciers. Local communities rely on the glacier-fed streamflow to get their water for drinking, irrigation, and livestock. Moreover, communities also rely on the tourism of hikers who come to the region to view the glaciers. As the temperatures increase, these glaciers are no longer in equilibrium with their current climate and are receding rapidly and decreasing the streamflow. This thesis examines surface air temperature from 858 weather stations across Ecuador, Peru, and Chile in order to analyze changes in trends and variability. Three time periods were studied: 1961--1990, 1971--2000, and 1981--2010. The greatest warming occurred during the period of 1971--2000 with 92% of the stations experiencing positive trends with a mean of 0.24°C/decade. There was a clear shift toward cooler temperatures at all latitudes and below elevations of 500 m during the most recent time period studied (1981--2010). Station temperatures were more strongly correlated with the El Nino Southern Oscillation (ENSO), than the Pacific Decadal Oscillation (PDO), and the Southern Annular Mode (SAM). A principal component analysis confirmed ENSO as the main contributor of variability with the most influence in the lower latitudes. There were clear multidecadal changes in correlation strength for the PDO. The PDO contributed the most to the increases in station temperature trends during the 1961--1990 period, consistent with the PDO shift to the positive phase in the middle of this period. There were many strong positive trends at individual stations during the 1971--2000 period; however, these trends could not fully be attributed to ENSO, PDO, or SAM, indicating anthropogenic effects of

  19. Characterising Late-Holocene glacier variability in the southern tropical Andes

    Science.gov (United States)

    Bromley, G.; Winckler, G.; Hall, B. L.; Schaefer, J. M.

    2011-12-01

    Accurate resolution of both the timing and magnitude of Late-Holocene climate events, such as the Little Ice Age, is vital in order to test different hypotheses for the causes and propagation of such climate variability. However, in contrast to higher latitudes, well-dated records from the tropics are relatively rare and the overall climatic structure of the last millennium remains unresolved. Much of this uncertainty stems from difficulties associated with radiocarbon dating in these dry, often high-altitude environments, a situation that now is being addressed through the application and refinement of cosmogenic surface-exposure methods. We present detailed Late-Holocene moraine records, resolved with radiocarbon and surface-exposure dating, from sites across the Andes of southern Peru. Specifically, we describe glacial records from both the arid Western Cordillera, where glaciation is limited by moisture availability, and the humid Eastern Cordillera, where ablation is controlled primarily by air temperature. In both locations, the most recent advance is marked by two to three unweathered terminal moraines located several hundred metres beyond the modern ice margins. Our chronology indicates that, while the advance occurred broadly in step with the classic 'Little Ice Age', the maximum glacial extent in southern Peru was achieved relatively early on and that the 18th and 19th centuries were dominated by glacier retreat. In a broader temporal context, our data also confirm that, in contrast to northern temperate latitudes, the event in southern Peru was the most recent significant interruption in a progressive Holocene retreat. The consistency in glacier response between the different climate zones suggests (i) that this pattern of Late-Holocene climate variability was of at least regional extent and (ii) that temperature fluctuations were the primary driving mechanism.

  20. Global climate change increases risk of crop yield losses and food insecurity in the tropical Andes.

    Science.gov (United States)

    Tito, Richard; Vasconcelos, Heraldo L; Feeley, Kenneth J

    2018-02-01

    One of the greatest current challenges to human society is ensuring adequate food production and security for a rapidly growing population under changing climatic conditions. Climate change, and specifically rising temperatures, will alter the suitability of areas for specific crops and cultivation systems. In order to maintain yields, farmers may be forced to change cultivation practices, the timing of cultivation, or even the type of crops grown. Alternatively, farmers can change the location where crops are cultivated (e.g., to higher elevations) to track suitable climates (in which case the plants will have to grow in different soils), as cultivated plants will otherwise have to tolerate warmer temperatures and possibly face novel enemies. We simulated these two last possible scenarios (for temperature increases of 1.3°C and 2.6°C) in the Peruvian Andes through a field experiment in which several traditionally grown varieties of potato and maize were planted at different elevations (and thus temperatures) using either the local soil or soil translocated from higher elevations. Maize production declined by 21%-29% in response to new soil conditions. The production of maize and potatoes declined by >87% when plants were grown under warmer temperatures, mainly as a result of the greater incidence of novel pests. Crop quality and value also declined under simulated migration and warming scenarios. We estimated that local farmers may experience severe economic losses of up to 2,300 US$ ha -1  yr -1 . These findings reveal that climate change is a real and imminent threat to agriculture and that there is a pressing need to develop effective management strategies to reduce yield losses and prevent food insecurity. Importantly, such strategies should take into account the influences of non-climatic and/or biotic factors (e.g., novel pests) on plant development. © 2017 John Wiley & Sons Ltd.

  1. Low Dimensional Embedding of Climate Data for Radio Astronomical Site Testing in the Colombian Andes

    Science.gov (United States)

    Chaparro Molano, Germán; Ramírez Suárez, Oscar Leonardo; Restrepo Gaitán, Oscar Alberto; Marcial Martínez Mercado, Alexander

    2017-10-01

    We set out to evaluate the potential of the Colombian Andes for millimeter-wave astronomical observations. Previous studies for astronomical site testing in this region have suggested that nighttime humidity and cloud cover conditions make most sites unsuitable for professional visible-light observations. Millimeter observations can be done during the day, but require that the precipitable water vapor column above a site stays below ˜10 mm. Due to a lack of direct radiometric or radiosonde measurements, we present a method for correlating climate data from weather stations to sites with a low precipitable water vapor column. We use unsupervised learning techniques to low dimensionally embed climate data (precipitation, rain days, relative humidity, and sunshine duration) in order to group together stations with similar long-term climate behavior. The data were taken over a period of 30 years by 2046 weather stations across the Colombian territory. We find six regions with unusually dry, clear-sky conditions, ranging in elevations from 2200 to 3800 masl. We evaluate the suitability of each region using a quality index derived from a Bayesian probabilistic analysis of the station type and elevation distributions. Two of these regions show a high probability of having an exceptionally low precipitable water vapor column. We compared our results with global precipitable water vapor maps and find a plausible geographical correlation with regions with low water vapor columns (˜10 mm) at an accuracy of ˜20 km. Our methods can be applied to similar data sets taken in other countries as a first step toward astronomical site evaluation.

  2. Mixed memory, (non) Hurst effect, and maximum entropy of rainfall in the tropical Andes

    Science.gov (United States)

    Poveda, Germán

    2011-02-01

    Diverse linear and nonlinear statistical parameters of rainfall under aggregation in time and the kind of temporal memory are investigated. Data sets from the Andes of Colombia at different resolutions (15 min and 1-h), and record lengths (21 months and 8-40 years) are used. A mixture of two timescales is found in the autocorrelation and autoinformation functions, with short-term memory holding for time lags less than 15-30 min, and long-term memory onwards. Consistently, rainfall variance exhibits different temporal scaling regimes separated at 15-30 min and 24 h. Tests for the Hurst effect evidence the frailty of the R/ S approach in discerning the kind of memory in high resolution rainfall, whereas rigorous statistical tests for short-memory processes do reject the existence of the Hurst effect. Rainfall information entropy grows as a power law of aggregation time, S( T) ˜ Tβ with = 0.51, up to a timescale, TMaxEnt (70-202 h), at which entropy saturates, with β = 0 onwards. Maximum entropy is reached through a dynamic Generalized Pareto distribution, consistently with the maximum information-entropy principle for heavy-tailed random variables, and with its asymptotically infinitely divisible property. The dynamics towards the limit distribution is quantified. Tsallis q-entropies also exhibit power laws with T, such that Sq( T) ˜ Tβ( q) , with β( q) ⩽ 0 for q ⩽ 0, and β( q) ≃ 0.5 for q ⩾ 1. No clear patterns are found in the geographic distribution within and among the statistical parameters studied, confirming the strong variability of tropical Andean rainfall.

  3. Floristic relationships among vegetation types of new zealand and the southern andes: similarities and biogeographic implications.

    Science.gov (United States)

    Ezcurra, Cecilia; Baccalá, Nora; Wardle, Peter

    2008-06-01

    Similarities between the floras of geographically comparable regions of New Zealand (NZ) and the southern Andes (SA) have interested biologists for over 150 years. The present work selects vegetation types that are physiognomically similar between the two regions, compares their floristic composition, assesses the environmental factors that characterize these matching vegetation types, and determines whether phylogenetic groups of ancestral versus modern origin are represented in different proportions in their floras, in the context of their biogeographic history. Floristic relationships based on 369 genera of ten vegetation types present in both regions were investigated with correspondence analysis (CA) and ascending hierarchical clustering (AHC). The resulting ordination and classification were related to the environmental characteristics of the different vegetation types. The proportions of different phylogenetic groups between the regions (NZ, SA) were also compared, and between forest and non-forest communities. Floristic similarities between NZ and SA tend to increase from forest to non-forest vegetation, and are highest in coastal vegetation and bog. The floras of NZ and SA also differ in their phylogenetic origin, NZ being characterized by an 'excess' of genera of basal origin, especially in forests. The relatively low similarities between forests of SA and NZ are related to the former being largely of in situ South American and Gondwanan origin, whereas the latter have been mostly reconstituted though transoceanic dispersal of propagules since the Oligocene. The greater similarities among non-forest plant communities of the two regions result from varied dispersal routes, including relatively recent transoceanic dispersal for coastal vegetation, possible dispersal via a still-vegetated Antarctica especially for bog plants, and independent immigration from Northern Hemisphere sources for many genera of alpine vegetation and grassland.

  4. The paradigm of paraglacial megafans of the San Juan river basin, Central Andes, Argentina

    Science.gov (United States)

    Suvires, Graciela M.

    2014-11-01

    The spatial distribution and several morphometric characteristics of the Quaternary alluvial fans of the San Juan River, in the province of San Juan, at the Central and Western part of Argentina, have been studied to classify them as paraglacial megafans, as well to ratify its depositional environmental conditions. The high sedimentary load exported by San Juan river from the Central Andes to the foreland depressions is estimated about 3,682,200 hm3. The large alluvial fans of Ullum-Zonda and Tulum valleys were deposited into deep tectonic depressions, during the Upper Pleistocene deglaciation stages. The outcome of collecting remotely sensed data, map and DEM data, geophysical data and much fieldwork gave access to morphometric, morphographic and morphogenetic data of these alluvial fans. The main drainage network was mapped on processed images using QGis (vers.2.0.1). Several fan morphometric parameters were measured, such as the size, the shape, the thickness, the surface areas and the sedimentary volume of exported load. The analyzed fans were accumulated in deep tectonic depressions, where the alluvium fill reaches 700 to 1200 m thick. Such fans do not reach the large size that other world megafans have, and this is due to tectonic obstacles, although the sedimentary fill average volume surpasses 514,000 hm3. The author proposes to consider Ullum-Zonda and Tulum alluvial fans as paraglacial megafans. According to the stratigraphic relationships of the tropical South American Rivers, the author considers that the San Juan paraglacial megafans would have occurred in the period before 24 ka BP , possibly corresponding to Middle Pleniglacial (ca 65-24ka BP). They record colder and more humid conditions compared with the present arid and dry conditions.

  5. The Tropical Andes without Snow and Ice - Impacts, Uncertainties and Challenges Ahead

    Science.gov (United States)

    Vuille, M. F.

    2015-12-01

    Climate change has lead to significant glacier retreat in the tropical Andes over the past several decades. Despite the apparent hiatus in warming along the Pacific coast, temperature continues to rise at higher elevations, putting smaller glaciers in lower lying mountain ranges on the verge of complete disappearance. As a result water availability and water quality in glacier-fed river systems will be reduced during the dry season. The lack of a seasonal snow cover in the tropics, which provides for an additional hydrologic buffer in mid-latitude mountain ranges, further exacerbates the situation. Altered precipitation regimes, including changes in total precipitation amount, changes in the rain/snow ratio, or changes in the wet season length will also affect water availability, but projections of these changes are currently fraught with uncertainty. The importance of glacier-fed water supply varies between regions and depends on the presence of other water regulators (reservoirs, wetlands), the length of the dry season and the trajectory of water demand (population growth, expanding economic activities). Here we will review downscaled CMIP5 model results for some of these mountain ranges and discuss the consequences of future warming and projected precipitation changes for the Andean cryosphere, while considering uncertainties associated with downscaling methodology, model dependency and choice of emission scenario. Adaptation strategies will be evaluated in the light of these results, discussing the need to pursue no-regret strategies, when implementing water conservation measures. Lessons learned from past adaptation and capacity building activities in the region will be discussed, emphasizing a) the need to strengthen the institutional standing of authorities involved in glacier research, b) alignment of capacity building and international cooperation with the national and regional needs and c) improvements to long-term climate and glacier monitoring programs

  6. Elevational Ranges of Montane Birds and Deforestation in the Western Andes of Colombia.

    Directory of Open Access Journals (Sweden)

    Natalia Ocampo-Peñuela

    Full Text Available Deforestation causes habitat loss, fragmentation, degradation, and can ultimately cause extinction of the remnant species. Tropical montane birds face these threats with the added natural vulnerability of narrower elevational ranges and higher specialization than lowland species. Recent studies assess the impact of present and future global climate change on species' ranges, but only a few of these evaluate the potentially confounding effect of lowland deforestation on species elevational distributions. In the Western Andes of Colombia, an important biodiversity hotspot, we evaluated the effects of deforestation on the elevational ranges of montane birds along altitudinal transects. Using point counts and mist-nets, we surveyed six altitudinal transects spanning 2200 to 2800 m. Three transects were forested from 2200 to 2800 m, and three were partially deforested with forest cover only above 2400 m. We compared abundance-weighted mean elevation, minimum elevation, and elevational range width. In addition to analysing the effect of deforestation on 134 species, we tested its impact within trophic guilds and habitat preference groups. Abundance-weighted mean and minimum elevations were not significantly different between forested and partially deforested transects. Range width was marginally different: as expected, ranges were larger in forested transects. Species in different trophic guilds and habitat preference categories showed different trends. These results suggest that deforestation may affect species' elevational ranges, even within the forest that remains. Climate change will likely exacerbate harmful impacts of deforestation on species' elevational distributions. Future conservation strategies need to account for this by protecting connected forest tracts across a wide range of elevations.

  7. A paleolimnological perspective on industrial-era metal pollution in the central Andes, Peru

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, Colin A. [Department of Geology, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3 (Canada)], E-mail: cacooke@ualberta.ca; Abbott, Mark B. [Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3 (Canada); Section of Anthropology, Carnegie Museum of Natural History, Pittsburgh, PA 15206 (United States)

    2008-04-15

    To date, few studies have investigated the environmental legacy associated with industrialization in the South American Andes. Here, we present an environmental archive of industrial pollution from {sup 210}Pb-dated lake cores recovered from Laguna Chipian, located near the Cerro de Pasco metallurgical region and Laguna Pirhuacocha, located near the Morococha mining region and the La Oroya smelting complex. At Laguna Chipian, trace metal concentrations increase beginning {approx} 1900 AD, coincident with the construction of the central Peruvian railway, and the rapid industrial development of the Cerro de Pasco region. Trace metal concentrations and fluxes peak during the 1950s before subsequently declining up-core (though remaining well above background levels). While Colonial mining and smelting operations are known to have occurred at Cerro de Pasco since at least 1630 AD, our sediment record preserves no associated metal deposition. Based on our {sup 14}C and {sup 210}Pb data, we suggest that this is due to a depositional hiatus, rather than a lack of regional Colonial pollution. At Laguna Pirhuacocha, industrial trace metal deposition first begins {approx} 1925 AD, rapidly increasing after {approx} 1950 AD and peaking during either the 1970s or 1990s. Trace metal concentrations from these lakes are comparable to some of the most polluted lakes in North America and Europe. There appears to be little diagenetic alteration of the trace metal record at either lake, the exception being arsenic (As) accumulation at Laguna Pirhuacocha. There, a correlation between As and the redox-sensitive element manganese (Mn) suggests that the sedimentary As burden is undergoing diagenetic migration towards the sediment-water interface. This mobility has contributed to surface sediment As concentrations in excess of 1100 {mu}g g{sup -1}. The results presented here chronicle a rapidly changing Andean environment, and highlight a need for future research in the rate and magnitude

  8. A paleolimnological perspective on industrial-era metal pollution in the central Andes, Peru.

    Science.gov (United States)

    Cooke, Colin A; Abbott, Mark B

    2008-04-15

    To date, few studies have investigated the environmental legacy associated with industrialization in the South American Andes. Here, we present an environmental archive of industrial pollution from (210)Pb-dated lake cores recovered from Laguna Chipian, located near the Cerro de Pasco metallurgical region and Laguna Pirhuacocha, located near the Morococha mining region and the La Oroya smelting complex. At Laguna Chipian, trace metal concentrations increase beginning ~1900 AD, coincident with the construction of the central Peruvian railway, and the rapid industrial development of the Cerro de Pasco region. Trace metal concentrations and fluxes peak during the 1950s before subsequently declining up-core (though remaining well above background levels). While Colonial mining and smelting operations are known to have occurred at Cerro de Pasco since at least 1630 AD, our sediment record preserves no associated metal deposition. Based on our (14)C and (210)Pb data, we suggest that this is due to a depositional hiatus, rather than a lack of regional Colonial pollution. At Laguna Pirhuacocha, industrial trace metal deposition first begins ~1925 AD, rapidly increasing after ~1950 AD and peaking during either the 1970s or 1990s. Trace metal concentrations from these lakes are comparable to some of the most polluted lakes in North America and Europe. There appears to be little diagenetic alteration of the trace metal record at either lake, the exception being arsenic (As) accumulation at Laguna Pirhuacocha. There, a correlation between As and the redox-sensitive element manganese (Mn) suggests that the sedimentary As burden is undergoing diagenetic migration towards the sediment-water interface. This mobility has contributed to surface sediment As concentrations in excess of 1100 microg g(-1). The results presented here chronicle a rapidly changing Andean environment, and highlight a need for future research in the rate and magnitude of atmospheric metal pollution.

  9. Lacustrine sedimentation in an altitude forest site, central Andes, Bolivia. Palaeo-climatic implications

    International Nuclear Information System (INIS)

    Sifeddine, A.; Bertaux, J.; Mourguiart, Ph.; Disnar, J.R.; Laggoun-Defarge, F.; Argollo, J.

    1998-01-01

    A sedimentological study of a 755 cm length core sampled in the middle of a marshy depression surrounded by a cloud forest in the central Andes reveals that this site has recorded important environmental variations during the last 50 000 years. For the most part (625 cm) the core is composed of detrital rich sediments deposited during the Upper Pleistocene. The highest amount of detrital influx underlines the Last Glacial Maximum which ranges from ca 29,000 14 C yr B.P. to ca 16,000 14 C yr B.P. (ca 18,500 cal yr B.P.), between two relatively humid phases. The sedimentation of the present Interglacial, starting at ca 12,500 14 C yr B.P. (14,500 cal yr B.P.), is mainly organic, as a consequence of the great development of soils and the forest vegetal cover the catchment area. The maximum extension of this vegetal cover ranging from 12,500 to ca 10,500 14 C yr B.P. (14,500 and 12,400 cal yr B.P.) is followed from 10,500 to 8,000 14 C yr B.P. (12,400 and 8,800 cal yr B.P.) by a drier period is revealed by the occurrence of micro-charcoals in the sediment. Between ca 8,000 and 4,000 14 C yr B.P. (8,800 and 4,500 cal yr B.P.), the sharp increase of micro-charcoals content, likely related to palaeo-fires, underlines an intensification of this dry trend. (authors)

  10. Quantifying modern erosion rates and river-sediment contamination in the Bolivian Andes

    Science.gov (United States)

    Vezzoli, Giovanni; Ghielmi, Giacomo; Mondaca, Gonzalo; Resentini, Alberto; Villarroel, Elena Katia; Padoan, Marta; Gentile, Paolo

    2013-08-01

    We use petrographic, mineralogical and geochemical data on modern river sediments of the Tupiza basin in the Bolivian Andes to investigate the relationships among human activity, heavy-metal contamination of sediments and modern erosion rates in mountain fluvial systems. Forward mixing model was used to quantify the relative contributions from each main tributary to total sediment load of the Tupiza River. The absolute sediment load was estimated by using the Pacific Southwest Inter Agency Committee model (PSIAC, 1968) after two years of geological field surveys (2009; 2010), together with data obtained from the Instituto Nacional del Agua public authority (INA, 2007), and suspended-load data from Aalto et al. (2006). Our results indicate that the sediment yield in the drainage basin is 910 ± 752 ton/km2year and the mean erosion rate is 0.40 ± 0.33 mm/year. These values compare well with erosion rates measured by Insel et al. (2010) using 10Be cosmogenic radionuclide concentrations in Bolivian river sediments. More than 40% of the Tupiza river load is produced in the upper part of the catchment, where highly tectonized and weathered rocks are exposed and coupled with sporadic land cover and intense human activity (mines). In the Rio Chilco basin strong erosion of upland valleys produce an increase of erosion (˜10 mm/year) and the influx of large amounts of sediment by mass wasting processes. The main floodplain of the Tupiza catchment represents a significant storage site for the heavy metals (˜657 ton/year). Fluvial sediments contain zinc, lead, vanadium, chromium, arsenic and nickel. Since the residence time of these contaminants in the alluvial plain may be more than 100 years, they may represent a potential source of pollution for human health.

  11. Elevational Ranges of Montane Birds and Deforestation in the Western Andes of Colombia.

    Science.gov (United States)

    Ocampo-Peñuela, Natalia; Pimm, Stuart L

    2015-01-01

    Deforestation causes habitat loss, fragmentation, degradation, and can ultimately cause extinction of the remnant species. Tropical montane birds face these threats with the added natural vulnerability of narrower elevational ranges and higher specialization than lowland species. Recent studies assess the impact of present and future global climate change on species' ranges, but only a few of these evaluate the potentially confounding effect of lowland deforestation on species elevational distributions. In the Western Andes of Colombia, an important biodiversity hotspot, we evaluated the effects of deforestation on the elevational ranges of montane birds along altitudinal transects. Using point counts and mist-nets, we surveyed six altitudinal transects spanning 2200 to 2800 m. Three transects were forested from 2200 to 2800 m, and three were partially deforested with forest cover only above 2400 m. We compared abundance-weighted mean elevation, minimum elevation, and elevational range width. In addition to analysing the effect of deforestation on 134 species, we tested its impact within trophic guilds and habitat preference groups. Abundance-weighted mean and minimum elevations were not significantly different between forested and partially deforested transects. Range width was marginally different: as expected, ranges were larger in forested transects. Species in different trophic guilds and habitat preference categories showed different trends. These results suggest that deforestation may affect species' elevational ranges, even within the forest that remains. Climate change will likely exacerbate harmful impacts of deforestation on species' elevational distributions. Future conservation strategies need to account for this by protecting connected forest tracts across a wide range of elevations.

  12. A paleolimnological perspective on industrial-era metal pollution in the central Andes, Peru

    International Nuclear Information System (INIS)

    Cooke, Colin A.; Abbott, Mark B.

    2008-01-01

    To date, few studies have investigated the environmental legacy associated with industrialization in the South American Andes. Here, we present an environmental archive of industrial pollution from 210 Pb-dated lake cores recovered from Laguna Chipian, located near the Cerro de Pasco metallurgical region and Laguna Pirhuacocha, located near the Morococha mining region and the La Oroya smelting complex. At Laguna Chipian, trace metal concentrations increase beginning ∼ 1900 AD, coincident with the construction of the central Peruvian railway, and the rapid industrial development of the Cerro de Pasco region. Trace metal concentrations and fluxes peak during the 1950s before subsequently declining up-core (though remaining well above background levels). While Colonial mining and smelting operations are known to have occurred at Cerro de Pasco since at least 1630 AD, our sediment record preserves no associated metal deposition. Based on our 14 C and 210 Pb data, we suggest that this is due to a depositional hiatus, rather than a lack of regional Colonial pollution. At Laguna Pirhuacocha, industrial trace metal deposition first begins ∼ 1925 AD, rapidly increasing after ∼ 1950 AD and peaking during either the 1970s or 1990s. Trace metal concentrations from these lakes are comparable to some of the most polluted lakes in North America and Europe. There appears to be little diagenetic alteration of the trace metal record at either lake, the exception being arsenic (As) accumulation at Laguna Pirhuacocha. There, a correlation between As and the redox-sensitive element manganese (Mn) suggests that the sedimentary As burden is undergoing diagenetic migration towards the sediment-water interface. This mobility has contributed to surface sediment As concentrations in excess of 1100 μg g -1 . The results presented here chronicle a rapidly changing Andean environment, and highlight a need for future research in the rate and magnitude of atmospheric metal pollution

  13. The effect of offset on fracture permeability of rocks from the Southern Andes Volcanic Zone, Chile

    Science.gov (United States)

    Pérez-Flores, P.; Wang, G.; Mitchell, T. M.; Meredith, P. G.; Nara, Y.; Sarkar, V.; Cembrano, J.

    2017-11-01

    The Southern Andes Volcanic Zone (SVZ) represents one of the largest undeveloped geothermal provinces in the world. Development of the geothermal potential requires a detailed understanding of fluid transport properties of its main lithologies. The permeability of SVZ rocks is altered by the presence of fracture damage zones produced by the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). We have therefore measured the permeability of four representative lithologies from the volcanic basement in this area: crystalline tuff, andesitic dike, altered andesite and granodiorite. For comparative purposes, we have also measured the permeability of samples of Seljadalur basalt, an Icelandic rock with widely studied and reported hydraulic properties. Specifically, we present the results of a systematic study of the effect of fractures and fracture offsets on permeability as a function of increasing effective pressure. Baseline measurements on intact samples of SVZ rocks show that the granodiorite has a permeability (10-18 m2), two orders of magnitude higher than that of the volcanic rocks (10-20 m2). The presence of throughgoing mated macro-fractures increases permeability by between four and six orders of magnitude, with the highest permeability recorded for the crystalline tuff. Increasing fracture offset to produce unmated fractures results in large increases in permeability up to some characteristic value of offset, beyond which permeability changes only marginally. The increase in permeability with offset appears to depend on fracture roughness and aperture, and these are different for each lithology. Overall, fractured SVZ rocks with finite offsets record permeability values consistent with those commonly found in geothermal reservoirs (>10-16 m2), which potentially allow convective/advective flow to develop. Hence, our results demonstrate that the fracture damage zones developed within the SVZ produce permeable regions, especially within the

  14. The Ongoing 2011 Eruption of Cordón Caulle (Southern Andes) and its Related Hazards

    Science.gov (United States)

    Amigo, A.; Lara, L. E.; Silva, C.; Orozco, G.; Bertin, D.

    2011-12-01

    On June 4, 2011, at 18:45 UTC, Cordón Caulle volcano (Southern Andes, 40.52S, 72.14W) erupted explosively after 51 years of quiescence. The last eruption occurred in 1960 and was triggered by the great Mw 9.5 Chile earthquake. The ongoing eruption started after 2 months of increased shallow seismicity as recorded by OVDAS (the volcano observatory at Sernageomin). This close monitoring effort allowed a timely eruption forecast with at least 3 hours of warning, which facilitated the crisis response. In addition to this successful performance, for the first time in Chile volcanic hazards were assessed in advance supporting the emergency management. In particular, tephra dispersal was daily forecasted using the ASHFALL advection-diffusion model and potential lahars and PDC impact zones were delineated according to numerical approaches. The first eruptive stage lasted 27 hours. It was characterized by ca. 15-km strong Plinian-like column, associated with the emission of 0.2 - 0.4 km3 of magma (DRE). Tephra fallout mostly occurred in Chile and Argentina, although fine particles and aerosols circumnavigated the globe twice, causing disruptions on air navigation across the Southern Hemisphere. The second ongoing eruptive stage has been characterized by persistent weak plumes and lava emission at effusion rates in the range of 20 and 60 m3/s, which total volume is estimated case of successful eruption forecast and hazards assessment but it is also an important case-study of silicic eruptions in an arc segment where mostly mafic magmas have been erupted during the Holocene.

  15. Land Cover Change in the Andes of Southern Ecuador—Patterns and Drivers

    Directory of Open Access Journals (Sweden)

    Giulia F. Curatola Fernández

    2015-03-01

    Full Text Available In the megadiverse tropical mountain forest in the Andes of southern Ecuador, a global biodiversity hotspot, the use of fire to clear land for cattle ranching is leading to the invasion of an aggressive weed, the bracken fern, which is threatening diversity and the provisioning of ecosystem services. To find sustainable land use options adapted to the local situation, a profound knowledge of the long-term spatiotemporal patterns of land cover change and its drivers is necessary, but hitherto lacking. The complex topography and the high cloud frequency make the use of remote sensing in this area a challenge. To deal with these conditions, we pursued specific pre-processing steps before classifying five Landsat scenes from 1975 to 2001. Then, we quantified land cover changes and habitat fragmentation, and we investigated landscape changes in relation to key spatial elements (altitude, slope, and distance from roads. Good classification results were obtained with overall accuracies ranging from 94.5% to 98.5% and Kappa statistics between 0.75 and 0.98. Forest was strongly fragmented due to the rapid expansion of the arable frontier and the even more rapid invasion by bracken. Unexpectedly, more bracken-infested areas were converted to pastures than vice versa, a practice that could alleviate pressure on forests if promoted. Road proximity was the most important spatial element determining forest loss, while for bracken the altitudinal range conditioned the degree of invasion in deforested areas. The annual deforestation rate changed notably between periods: ~1.5% from 1975 to 1987, ~0.8% from 1987 to 2000, and finally a very high rate of ~7.5% between 2000 and 2001. We explained these inconstant rates through some specific interrelated local and national political and socioeconomic drivers, namely land use policies, credit and tenure incentives, demography, and in particular, a severe national economic and bank crisis.

  16. Neogene paleoelevation of intermontane basins in a narrow, compressional mountain range, southern Central Andes of Argentina

    Science.gov (United States)

    Hoke, Gregory D.; Giambiagi, Laura B.; Garzione, Carmala N.; Mahoney, J. Brian; Strecker, Manfred R.

    2014-11-01

    The topographic growth of mountain ranges at convergent margins results from the complex interaction between the motion of lithospheric plates, crustal shortening, rock uplift and exhumation. Constraints on the timing and magnitude of elevation change gleaned from isotopic archives preserved in sedimentary sequences provide insight into how these processes interact over different timescales to create topography and potentially decipher the impact of topography on atmospheric circulation and superposed exhumation. This study uses stable isotope data from pedogenic carbonates collected from seven different stratigraphic sections spanning different tectonic and topographic positions in the range today, to examine the middle to late Miocene history of elevation change in the central Andes thrust belt, which is located immediately to the south of the Altiplano-Puna Plateau, the world's second largest orogenic plateau. Paleoelevations are calculated using previously published local isotope-elevation gradients observed in modern rainfall and carbonate-formation temperatures determined from clumped isotope studies in modern soils. Calculated Neogene basin paleoelevations are between 1 km and 1.9 km for basins that today are located between 1500 and 3400 m elevation. Considering the modern elevation and δ18O values of precipitation at the sampling sites, three of the intermontane basins experienced surface uplift between the end of deposition during the late Miocene and present. The timing of elevation change cannot be linked to any documented episodes of large-magnitude crustal shortening. Paradoxically, the maximum inferred surface uplift in the core of the range is greatest where the crust is thinnest. The spatial pattern of surface uplift is best explained by eastward migration of a crustal root via ductile deformation in the lower crust and is not related to flat-slab subduction.

  17. The Influence of the Madden-Julian Oscillation (mjo) on Extreme Rainfall Over the Central and Southern Peruvian Andes

    Science.gov (United States)

    Heidinger, H.; Jones, C.; Carvalho, L. V.

    2015-12-01

    Extreme rainfall is important for the Andean region because of the large contribution of these events to the seasonal totals and consequent impacts on water resources for agriculture, water consumption, industry and hydropower generation, as well as the occurrence of floods and landslides. Over Central and Southern Peruvian Andes (CSPA), rainfall exceeding the 90th percentile contributed between 44 to 100% to the total Nov-Mar 1979-2010 rainfall. Additionally, precipitation from a large majority of stations in the CSPA exhibits statistically significant spectral peaks on intraseasonal time-scales (20 to 70 days). The Madden-Julian Oscillation (MJO) is the most important intraseasonal mode of atmospheric circulation and moist convection in the tropics and the occurrence of extreme weather events worldwide. Mechanisms explaining the relationships between the MJO and precipitation in the Peruvian Andes have not been properly described yet. The present study examines the relationships between the activity and phases of the MJO and the occurrence of extreme rainfall over the CSPA. We found that the frequency of extreme rainfall events increase in the CSPA when the MJO is active. MJO phases 5, 6 and 7 contribute to the overall occurrence of extreme rainfall events over the CSPA. However, how the MJO phases modulate extreme rainfall depends on the location of the stations. For instance, extreme precipitation (above the 90th percentile) in stations in the Amazon basin are slightly more sensitive to phases 2, 3 and 4; the frequency of extremes in stations in the Pacific basin increases in phases 5, 6 and 7 whereas phase 2, 3 and 7 modulates extreme precipitation in stations in the Titicaca basin. Greater variability among stations is observed when using the 95th and 99th percentiles to identify extremes. Among the main mechanisms that explain the increase in extreme rainfall events in the Peruvian Andes is the intensification of the easterly moisture flux anomalies, which

  18. The Andes hantavirus NSs protein is expressed from the viral small mRNA by a leaky scanning mechanism.

    Science.gov (United States)

    Vera-Otarola, Jorge; Solis, Loretto; Soto-Rifo, Ricardo; Ricci, Emiliano P; Pino, Karla; Tischler, Nicole D; Ohlmann, Théophile; Darlix, Jean-Luc; López-Lastra, Marcelo

    2012-02-01

    The small mRNA (SmRNA) of all Bunyaviridae encodes the nucleocapsid (N) protein. In 4 out of 5 genera in the Bunyaviridae, the smRNA encodes an additional nonstructural protein denominated NSs. In this study, we show that Andes hantavirus (ANDV) SmRNA encodes an NSs protein. Data show that the NSs protein is expressed in the context of an ANDV infection. Additionally, our results suggest that translation initiation from the NSs initiation codon is mediated by ribosomal subunits that have bypassed the upstream N protein initiation codon through a leaky scanning mechanism.

  19. Drainage - Structure Correlation in tectonically active Regions: Case studies in the Bolivian and Colombian Andes

    Science.gov (United States)

    Zeilinger, Gerold; Parra, Mauricio; Kober, Florian

    2017-04-01

    It is widely accepted, that drainage patterns are often controlled by tectonics/climate and geology/rheology. Classical drainage patterns can be found 1) in fault-and-thrust belt, where rives follow the valleys parallel or cut perpendicular to strike trough the ridges, forming a trellis pattern, 2) at dome structures where the drainage form a radial pattern or 3) rectangular patterns in strongly fractured regions. In this study, we focus on fault-and-thrust belts, that undergone different phases of tectonic activity. According to classical models, the deformation is propagating into the foreland, hence being youngest at the frontal part and getting successively older towards the axis of the orogen. Drainage patterns in the more interior parts of the orogenic wedge should be then less influenced by the direction of structures, as landscape evolution is changing to a tectonic passive stage. This relationship might represent the transience and maturity of drainage pattern evolution. Here we study drainage patterns of the Bolivian and the eastern Colombian Andes by comparing the relative orientation of the drainage network with the orogen structural grain. The drainage is extracted from Digital Elevation Models (SRTM 30 m) and indexed by their Strahler Order. Order 1 channels have an upstream area of 1 km2. The direction of all segments is analyzed by linear directional mean function that results in the mean orientation of input channels with approx. 500 m average length. The orientation of structures for different structural domains is calculated using the same function on digitized faults and fold-axis. Rose diagrams show the length-weighted directional distribution of structures, of higher (>= 4) and of lower order (<= 3) channels. The structural trend in the Bolivian Andes is controlled by the orocline, where a predominant NW-SE trend turns into an N-S trend at 18°S and where the eastern orogen comprise from west to east, the Eastern Cordillera (EC), the

  20. El represamiento y aluvión del río Santa Cruz, Andes Principales (31°40'S), provincia de San Juan

    OpenAIRE

    Patricio E. D'odorico; Daniel J. Pérez; Nicolás Sequeira; Luis Fauqué

    2009-01-01

    En la región de los Andes Principales sanjuaninos, existe una alta concentración de deslizamientos, cuyos depósitos han originado represamientos naturales. El colapso de estos diques generados por movimientos de ladera es el proceso evolutivo más probable de estas geoformas. El análisis de imágenes satelitales y fotos aéreas permite reconstruir las características y el origen de los deslizamientos que formaron esos diques naturales. En esta región de los Andes Principales, el rápido levantami...

  1. Phytogeography of the vascular páramo flora of Ramal de Guaramacal (Andes, Venezuela) and its ties to other páramo floras

    OpenAIRE

    Cuello, N.L.; Cleef, A.M.; Aymard, G.

    2010-01-01

    Ramal de Guaramacal is an outlier and lower elevation mountain range located at the northeastern end of the Venezuelan Andes. Phytogeographical patterns and affinities of the low altitude and wet vascular páramo flora of Ramal de Guaramacal, have been studied with emphasis in to the analysis of the floristic connections of the Guaramacal páramo flora with the neighboring dry páramos of the Sierra Nevada de Mérida and other páramo floras of the northern Andes and Central America. A total of 25...

  2. Effect of Moxidectin Treatment at Peripartum on Gastrointestinal Parasite Infections in Ewes Raised under Tropical Andes High Altitude Conditions

    Science.gov (United States)

    Vargas-Duarte, J. J.; Lozano-Márquez, H.; Grajales-Lombana, H. A.; Manrique-Perdomo, C.; Martínez-Bello, D. A.; Saegerman, C.; Raes, M.; Kirschvink, N.

    2015-01-01

    This study tested the impact of moxidectin at peripartum on nematode fecal egg count (FEC) and clinical parameters on ewes in the high altitude tropical Andes of Colombia. FEC and clinical evaluations were performed on 9 occasions in 43 naturally infected ewes before and during gestation and after lambing. Moxidectin (Mox, 200 µg kg−1) was applied at late pregnancy (T 1, n = 15) or 48 hours after parturition (T 2, n = 14). 14 untreated ewes served as controls (C). Suckling lambs (n = 58) remained untreated and underwent four clinical and parasitological evaluations until 8 weeks after birth. Mox efficacy equaled 99.3% (T 1) and 96.9% (T 2). Highest mean FEC value reflecting periparturient nematode egg rise (PPER) was recorded in C ewes at 4–6 weeks after lambing. Significant FEC reductions were found in T 1 (94.8%) and T 2 (96.7%) ewes (p ewes-group independent increase in FEC before weaning (p < 0.05). Clinical parameters (anemia and diarrhea) showed time- and treatment-related differences (p < 0.05). Monitoring of FEC and clinical parameters linked to gastrointestinal parasite infections allowed demonstrating that postpartum or preweaning are two critical periods to nematode infection for sheep raised under tropical Andes high altitude conditions. Use of Mox as anthelmintic treatment prevented PPER. PMID:26078913

  3. Mesozoic–Cenozoic Evolution of the Western Margin of South America: Case Study of the Peruvian Andes

    Directory of Open Access Journals (Sweden)

    Laura Gonzalez

    2013-06-01

    Full Text Available Based on the structural style and physiographic criteria, the Central Andes of Peru can be divided into segments running parallel to the Pacific coast. The westernmost segment, the Coastal Belt, consists of a Late Jurassic–Cretaceous volcanic arc sequence that was accreted to the South American craton in Cretaceous times. The Mesozoic strata of the adjacent Western Cordillera represent an ENE-vergent fold-and-thrust belt that formed in Eocene times. Tight upright folds developed above a shallow detachment horizon in the West, while more open folds formed above a deeper detachment horizon towards the East and in the neighboring Central Highlands. A completely different style with steeply dipping reverse faults and open folds affecting the Neoproterozoic crystalline basement is typical for the Eastern Cordillera. The Subandean Zone is characterized by mainly NE-vergent imbricate thrusting which occurred in Neogene times. A quantitative estimate of the shortening of the orogen obtained from balanced cross-sections indicates a total shortening of 120–150 km (24%–27%. This shortening was coevel with the Neogene westward drift of South America, occurred at rates between 3 and 4.7 mm/year and was responsible for the high elevation of the Peruvian Andes.

  4. How typical are the last 20,000 years of climatic and vegetation change in the tropical Andes?

    Science.gov (United States)

    Gosling, W. D.; Urrego, D. H.; Hanselman, J. A.; Valencia, B.; Bush, M. B.; Silman, M. R.

    2006-12-01

    A consensus of global circulation models highlights the southern tropical Andes as the biodiversity hotspot most likely to experience biome shift in the next century. The pace of the ongoing change finds its nearest parallel in that of the Younger Dryas at high latitudes. However, in the tropical Andes of Peru and Bolivia we find that there was no such rapid temperature change within the last 40,000 years. Rates of temperature change across the deglacial interval (which may begin as early as c. 22,000 cal. yr BP) are one to two orders of magnitude slower than those forecasted for the next century, and differed little from those of the full glacial. Indeed, the fastest rates of vegetation change are responses to Holocene drought and human activity, not Pleistocene/Holocene warming. Sedimentary data from long records on the Altiplano provide records of earlier interglacials (MIS 5e, 7 and 9), but do not have the chronological control to provide assessments of rate of change. Nevertheless, those records do provide evidence of marked similarities in the development of each interglacial, with some divergence seen at full interglacial conditions.

  5. Landslide susceptibility near highways is increased by 1 order of magnitude in the Andes of southern Ecuador, Loja province

    Science.gov (United States)

    Brenning, A.; Schwinn, M.; Ruiz-Páez, A. P.; Muenchow, J.

    2015-01-01

    Mountain roads in developing countries are known to increase landslide occurrence due to often inadequate drainage systems and mechanical destabilization of hillslopes by undercutting and overloading. This study empirically investigates landslide initiation frequency along two paved interurban highways in the tropical Andes of southern Ecuador across different climatic regimes. Generalized additive models (GAM) and generalized linear models (GLM) were used to analyze the relationship between mapped landslide initiation points and distance to highway while accounting for topographic, climatic, and geological predictors as possible confounders. A spatial block bootstrap was used to obtain nonparametric confidence intervals for the odds ratio of landslide occurrence near the highways (25 m distance) compared to a 200 m distance. The estimated odds ratio was 18-21, with lower 95% confidence bounds >13 in all analyses. Spatial bootstrap estimation using the GAM supports the higher odds ratio estimate of 21.2 (95% confidence interval: 15.5-25.3). The highway-related effects were observed to fade at about 150 m distance. Road effects appear to be enhanced in geological units characterized by Holocene gravels and Laramide andesite/basalt. Overall, landslide susceptibility was found to be more than 1 order of magnitude higher in close proximity to paved interurban highways in the Andes of southern Ecuador.

  6. Landslide susceptibility near highways is increased by one order of magnitude in the Andes of southern Ecuador, Loja province

    Science.gov (United States)

    Brenning, A.; Schwinn, M.; Ruiz-Páez, A. P.; Muenchow, J.

    2014-03-01

    Mountain roads in developing countries are known to increase landslide occurrence due to often inadequate drainage systems and mechanical destabilization of hillslopes by undercutting and overloading. This study empirically investigates landslide initiation frequency along two paved interurban highways in the tropical Andes of southern Ecuador across different climatic regimes. Generalized additive models (GAM) and generalized linear models (GLM) were used to analyze the relationship between mapped landslide initiation points and distance to highway while accounting for topographic, climatic and geological predictors as possible confounders. A spatial block bootstrap was used to obtain non-parametric confidence intervals for the odds ratio of landslide occurrence near the highways (25 m distance) compared to a 200 m distance. The estimated odds ratio was 18-21 with lower 95% confidence bounds > 13 in all analyses. Spatial bootstrap estimation using the GAM supports the higher odds ratio estimate of 21.2 (95% confidence interval: 15.5-25.3). The highway-related effects were observed to fade at about 150 m distance. Road effects appear to be enhanced in geological units characterized by Holocene gravels and Laramide andesite/basalt. Overall, landslide susceptibility was found to be more than one order of magnitude higher in close proximity to paved interurban highways in the Andes of southern Ecuador.

  7. Les effets de l’émigration paysanne dans les Andes équatoriennes : une lecture photographique

    Directory of Open Access Journals (Sweden)

    Nasser Rebaï

    2011-07-01

    Full Text Available Dans les Andes équatoriennes, les effets de l’émigration paysanne sont partout visibles. Si dans la province de l’Azuay, on assiste à la diminution des superficies cultivées et à la réorganisation des tâches agricoles, on observe par ailleurs l’émergence d’une agriculture commerciale orientée vers le marché urbain régional. En procédant à la description de photographies prises à la campagne comme à la ville, nous chercherons à expliquer l’ensemble de ces mutations, avant de nous interroger plus largement sur l’avenir des exploitations familiales dans cette région.En los Andes ecuatorianos, los efectos de la migración campesina son visibles por todas partes. Si en la provincia del Azuay, se asiste a la disminución de las superficies cultivadas y a la reorganización de las tareas agrícolas, observamos por otro lado la emergencia de una agricultura comercial orientada hacia el mercado urbano regional. Procediendo a la descripción de fotografías tomadas en la campo como en la ciudad, procuraremos explicar el conjunto de estas mutaciones, antes de preguntarnos más ampliamente sobre el futuro de las explotaciones familiares en esta región.

  8. Unexpected Climatological Behavior of MLT Gravity Wave Momentum Flux in the Lee of the Southern Andes Hot Spot

    Science.gov (United States)

    DeWit, R. J.; Janches, D.; Fritts, D. C.; Stockwell, R. G.; Coy, L.

    2017-01-01

    The Southern Argentina Agile MEteor Radar (SAAMER), located at Tierra del Fuego (53.7degS, 67.7degW), has been providing near-continuous high-resolution measurements of winds and high-frequency gravity wave (GW) momentum fluxes of the mesopause region since May 2008. As SAAMER is located in the lee of the largest seasonal GW hot spot on Earth, this is a key location to study GWs and their interaction with large-scale motions. GW momentum flux climatologies are shown for the first time for this location and discussed in light of these unique dynamics. Particularly, the large eastward GW momentum fluxes during local winter are surprising, as these observations cannot be explained by the direct upward propagation of expected large-amplitude mountain waves (MWs) through the eastward stratospheric jet. Instead, these results are interpreted as secondary GWs propagating away from stratospheric sources over the Andes accompanying MW breaking over the Southern Andes.

  9. Las puntas y rejas prehispánicas de metal en los Andes y su continuidad hasta el presente

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available Les pointes et les socs préhispaniques en métal dans les Andes et leur continuité jusqu’à aujourd’hui Résumé: Cet article tente de montrer la continuité entre les instruments à usages multiples composés de pointes et des socs en cuivre arsenical insérés sur des manches en bois qui ont été élaborés à partir de 900 d. C. par les Sicán de Batán Grande, département de Lambayeque (Pérou, et certains instruments en acier utilisés actuellement dans les Andes du nord du Pérou et du sud de l’Équateur : les barretas, barretillas, barretones et les petites pelles. Il s’agit d’indiquer, sur la base d’informations ethnographiques, la relation entre ces instruments et les allachus, kituchis et chaquitacllas dont se servent les paysans des hautes terres du centre et du sud du Pérou, ceci dans le but de contribuer à l’élaboration d’une histoire de la technologie andine. Este artículo intenta, por un lado, mostrar la continuidad entre las herramientas multiusos elaboradas a partir de 900 d.C. por los sicanes de Batán Grande, departamento de Lambayeque (Perú, compuestas por puntas y rejas de cobre arsenical insertadas en cabos de madera y algunos de los instrumentos de acero utilizados actualmente en los Andes del norte del Perú y del sur del Ecuador: barretas, barretillas, barretones y pequeñas lampas. Y por otro, indicar, en base a datos etnográficos, la relación entre estos instrumentos y los allachus, kituchis y chaquitacllas que emplean los campesinos de las tierras alto andinas del centro y el sur del Perú. Esto con la finalidad de abogar para la elaboración de una historia de la tecnología andina. Prehispanic metal points and ploughshares in the Andes and their continuity until the present Abstract: This article shows the continuity in the production of multiple use tools that where made beginning AD 900 by the Sicán people of Batán Grande, in the Department of Lambayeque, Peru. These tools are arsenical cooper

  10. Estimation of slip scenarios of mega-thrust earthquakes and strong motion simulations for Central Andes, Peru

    Science.gov (United States)

    Pulido, N.; Tavera, H.; Aguilar, Z.; Chlieh, M.; Calderon, D.; Sekiguchi, T.; Nakai, S.; Yamazaki, F.

    2012-12-01

    We have developed a methodology for the estimation of slip scenarios for megathrust earthquakes based on a model of interseismic coupling (ISC) distribution in subduction margins obtained from geodetic data, as well as information of recurrence of historical earthquakes. This geodetic slip model (GSM) delineates the long wavelength asperities within the megathrust. For the simulation of strong ground motion it becomes necessary to introduce short wavelength heterogeneities to the source slip to be able to efficiently simulate high frequency ground motions. To achieve this purpose we elaborate "broadband" source models constructed by combining the GSM with several short wavelength slip distributions obtained from a Von Karman PSD function with random phases. Our application of the method to Central Andes in Peru, show that this region has presently the potential of generating an earthquake with moment magnitude of 8.9, with a peak slip of 17 m and a source area of approximately 500 km along strike and 165 km along dip. For the strong motion simulations we constructed 12 broadband slip models, and consider 9 possible hypocenter locations for each model. We performed strong motion simulations for the whole central Andes region (Peru), spanning an area from the Nazca ridge (16^o S) to the Mendana fracture (9^o S). For this purpose we use the hybrid strong motion simulation method of Pulido et al. (2004), improved to handle a general slip distribution. Our simulated PGA and PGV distributions indicate that a region of at least 500 km along the coast of central Andes is subjected to a MMI intensity of approximately 8, for the slip model that yielded the largest ground motions among the 12 slip models considered, averaged for all assumed hypocenter locations. This result is in agreement with the macroseismic intensity distribution estimated for the great 1746 earthquake (M~9) in central Andes (Dorbath et al. 1990). Our results indicate that the simulated PGA and PGV for

  11. Glacial recession in the Tropical Andes from the Little Ice Age: the case of Ampato Volcanic Complex (Southern Peru

    Science.gov (United States)

    Alcalá, J.; Palacios, D.; Zamorano, J. J.

    2010-03-01

    Data published over the last decade reveal substantial glacial recession in the tropical Andes since the Little Ice Age (LIA), (Ramirez, et al., 2001; Rabatel, et al., 2005; Rabatel, et al., 2008; Vuille, et al., 2008; Hastenrath, 2009; Jomelli, et al., 2009), and a growing rate of recession since the 1980’s caused by global warming (Ramirez, et al., 2001; Vuille, et al., 2008). Today there is great interest in the evolution of these ice masses due to heightened awareness of climate change and of the strategic importance that glaciers have as a hydrologic resource for communities in arid climate zones in the tropical Andes (Mark, 2008; Vuille et al., 2008). Cordillera Blanca forms part of the Andes Mountains of northern Peru, and is a chosen site for many studies on glacier evolution. Vuille et al. 2008 determined that a considerable area of ice mass was lost at Huascarán-Chopicalqui glacier (18% from 1920-1970) and Astesonraju glacier (20% from 1962-2003). Studies at Coropuna volcano, which has the most extensive glacier field in the western range of southern Peru, also report a strong melting trend that began with only minimal recession from 1955-1986 (4%), but increased to 14% from 1986-2007 (Úbeda et al., 2009). Only a few of the Andes glaciers are consistently monitored, and the most comprehensive data are for Chacaltaya and Zongo glaciers (16º S) in Bolivia. Since the maximum LIA, Chacaltaya has lost 89% of its surface area, particularly in recent years. By 1983, the totaled loss was five times the shrinkage for the period 1940-1963 (Ramirez, et al., 2001). Zongo glacier maintained equilibrium from 1956-1975, but later experienced a period dominated by continuous recession (Soruco, et al., 2009). This study expands current knowledge of glacier evolution since the LIA in the Central Volcanic Zone (CVZ; 14º - 27º S) (Stern, 2004) of the Andes. The study site was chosen in an area that had never been used for preliminary research of this type, concretely

  12. Epstein - Barr Virus

    OpenAIRE

    Štorkánová, Lenka

    2011-01-01

    Epstein-Barr virus Bachelor thesis summarizes the findings of Epstein-Barr virus (EBV), its general characteristics, transmission and spread of the virus, symptoms of disease and subsequent therapy and recovery. More specifically, it focuses on infectious mononucleosis, as well as more generally to other diseases, which the Epstein-Barr virus causes. It includes details of the vaccine against EB virus. There are the statistics on the incidence of infectious mononucleosis.

  13. Actividad microbiológica y biomasa microbiana en suelos cafetaleros de los Andes venezolanos

    Directory of Open Access Journals (Sweden)

    Jorge E. Paolini Gómez

    2018-01-01

    Full Text Available En Venezuela el café (Coffea arabica L. ocupa un área aproximada de 200 000 ha, distribuidos principalmente en las zonas montañosas de Los Andes. Tradicionalmente, el café se cultiva con pocos insumos bajo la sombra de árboles de la familia de las leguminosas y de otros arbustos. En años recientes con la adopción de cultivares de alta productividad, notable precocidad y tamaño reducido se está produciendo café a plena exposición solar con fertilización mineral y uso de pesticidas. Las propiedades microbiológicas del suelo especialmente aquellas relacionadas con el flujo de energía y el reciclaje de nutrientes responden de forma rápida y sensible a los cambios de las condiciones del suelo mucho antes que por ejemplo el carbono orgánico, y de este modo, suministran una información anticipada sobre las alteraciones de la calidad del mismo. En este estudio se comparó la actividad microbiológica (respiración basal, la biomasa microbiana y los parámetros ecofisiológicos en suelos a nivel superficial (0-5 cm de ocho fincas cafetaleras en los municipios de Mérida y Trujillo donde se encuentran tres sistemas de producción: tradicional, convencional y orgánico. Las fincas con agricultura orgánica presentaron los mayores valores de carbono orgánico total, carbono hidrosoluble, respiración basal y biomasa microbiana en comparación con las de manejo tradicional y convencional; con lo cual la producción orgánica es un sistema de manejo más sostenible por la mayor conservación de los recursos naturales y la producción más amigable y armónica con el ambiente. En el caso del manejo convencional, la adición de fertilizantes y pesticidas afecta de forma negativa el bienestar de los microorganismos y los hace más ineficientes en el uso del carbono y la energía.

  14. Studying the Effects of Amazonian Land Cover Change on Glacier Mass Balance in the Tropical Andes

    Science.gov (United States)

    Mark, B. G.; Fernandez, A.; Gabrielli, P.; Montenegro, A.; Postigo, J.; Hellstrom, R. A.

    2017-12-01

    Recent research has highlighted several ongoing environmental changes occurring across Tropical South America, including Andean glacier retreat, drought, as well as changes in land-use and land-cover. As the regional climate of the area is mostly characterized by land-ocean interactions, the atmospheric convection in the Amazon, and the effect of the Andes on circulation patterns, it follows that changes in one of those regions may affect the other. Most scholars who have studied the causes of tropical glaciers' fluctuations have not analyzed the linkages with changes in the Amazon with the same attention paid to the influence of Pacific sea surface temperature. Here we study the response of glacier surface mass balance in the Cordillera Blanca, Peru (10°S), to a scenario where the Amazonian rainforest is replaced by savannas. We ran climatic simulations at 2-km spatial resolution utilizing the Weather Research and Forecasting (WRF) model considering two scenarios: (a) control (CRTL), with today's rainforest extent; and (b) land cover change (LCC), where all the rainforest was replaced by savanna. WRF output was in turn ingested into a glacier energy and mass balance (GEMB) model that we validate by reconstructing both the accumulated mass balance from available observations, and the altitudinal distribution of mass balance in the region. Seasonal comparison between CRTL and LCC scenarios indicates that forest replacement by savanna results in more positive glacier mass balance. This shift to more positive mass balance contrasts with a (WRF) modeled rise in the elevation of the freezing line (0°C) between 30 to 120 m for the LCC scenario. Our results are surprising because most previous studies have shown that reducing Amazon forest cover diminishes rainfall and increases temperature, suggesting that glaciers should lose mass. We hypothesize and discuss implications of possible land-atmospheric processes that might drive this tropical glacier response to

  15. The Riscos Bayos Ignimbrites of the Caviahue-Copahue volcanic caldera complex, southern Andes, Argentina

    Science.gov (United States)

    Colvin, A.; Merrill, M.; Demoor, M.; Goss, A.; Varekamp, J. C.

    2004-05-01

    The Caviahue-Copahue volcanic complex (38 S, 70 W) is located on the eastern margin of the active arc in the southern Andes, Argentina. Volcán Copahue, an active stratovolcano which hosts an active hydrothermal system, sits on the southwestern rim of the elliptical Caviahue megacaldera (17 x 15 km). The caldera wall sequences are up to 0.6 km thick and consist of lavas with 51 -69 percent SiO2 and 0.2 - 5 percent MgO as well as breccias, dikes, sills, domes and minor ignimbrites. Andesitic lava flows also occur within the caldera, and are overlain by a chaotic complex of silicic lava and intracaldera pyroclastic flow deposits. The eastern wall sequence is capped by several extracaldera ignimbrites (Riscos Bayos formation) of about 50 m maximum thickness which extend 30 km east-southeast of the caldera. Young back-arc alkali basalt scoria cones occur east of the Caviahue-Copahue volcanic complex. The eruption of the Riscos Bayos formation at about 1.1 Ma (12 km cubed) may be related to the Caviahue caldera formation, though the Riscos Bayos account for only about 7 percent of the caldera volume. The Riscos Bayos consists of three lithic-bearing flow units: a grey basal flow, a tan middle flow and a bright-white, highly indurated uppermost flow. The basal unit consists of white and grey pumice fragments, black scoria clasts, black obsidian clasts (which give it the grey color), and accidental volcanic lithics set in a matrix of ash and crystals. The middle unit is composed of large mauve pumice fragments and accidental lithics set in a fine tan ash groundmass. The uppermost unit is composed of small pink and white pumice fragments set in a matrix of fine white ash. These pumices carry quartz and biotite crystals, whereas the lower two units are orthopyroxene-bearing trachy-dacites. The Caviahue-Copahue magmas all bear arc signatures, but possibly some magma mixing between the andesitic arc magmas and basaltic back-arc magmas may have occurred. The evolved top layer

  16. Application of enzyme leach soil analysis for epithermal gold exploration in the Andes of Ecuador

    Energy Technology Data Exchange (ETDEWEB)

    Williams, T.M.; Gunn, A.G. [British Geological Survey, Nottingham (United Kingdom)

    2002-07-01

    Enzyme Leach (EL) soil surveys were undertaken over known epithermal Au mineralisation at El Mozo and Llano Largo, Azuay, Ecuador to assess the utility of the technique for identifying such deposits in the Ecuadorian Andes. The results indicate the development of both apical- and oxidation-type EL anomalies over auriferous structures at the two sites, the former systematically incorporating Au, and the latter Cl and Br. The spectrum of elements responsive to mineralisation at El Mozo (Cl, Br, I, La, Ce, Nd, Cu, Pb, Au, As, Sb, Ag, Zr, Sr) was found to be considerably greater than at Llano Largo (Cl, Br, Au, As, Sb, Ag, Zn), probably reflecting the contrasting high- and low-sulphidation assemblages of the two prospects. Ratios of EL versus aqua-regia extractable trace element concentrations ranged from 1: < 100 for Mn to 1: >400 for chalcophile elements such as Pb, Sb, As, Bi and Ag. Strong correlations between the concentrations of several analytes (including Mn, Sr, Cu, Co, As) extracted by the two procedures indicate, however, that EL datasets are extensively influenced by bulk matrix composition. Spatial variations of EL extractable Mn were found to exert no major influence on apical or oxidation suite anomaly patterns at El Mozo. However, Mn-normalisation of halogen data for Llano Largo elucidated otherwise obscure oxidation features, potentially related to Au mineralisation. Ratios between elements subject to apical enrichment and those of the oxidation suite (e.g. Cl/Au and Bi/Br) were found to highlight known Au targets with improved clarity. The formation mechanism of the recorded Au anomalies is uncertain, but may involve physical enrichment of Au in the soil during pedogenesis with subsequent in-situ formation of (EL soluble) Au halide complexes. The strength of such apical features is, in part, probably a function of the minimal depths to mineralisation which characterise El Mozo and Llano Largo. Oxidation halos formed by volatile non-metallic elements

  17. Mining and drought in the tropical Andes: a case study of lake Poopó

    Science.gov (United States)

    Zogheib, C.

    2017-12-01

    The respective impacts of mining water withdrawals and El Niño-related droughts on water availability in the Altiplano region of the tropical Andes were investigated. The naturally semi-arid to arid climate of the region is highly vulnerable to the effects of the El Niño Southern Oscillation (ENSO) as well as changes to the Bolivian High upper troposphere circulation. The 2015-2016 El Niño event displayed a maximal Oceanic Niño Index (ONI) of up to 2.2 °C, comparable with the 1998-1999 event, considered as the most severe of the 20th century with a maximal ONI of 2.5 °C. This has severely impacted the Altiplano region. Whereas mining has been found to affect observed water quality in the region, its influence on water availability has not been extensively examined. In light of these observations, the case of Lake Poopó, a water body at the intersection of both these climatic and anthropogenic influences, was further analyzed. The lake was officially declared dry in January 2016 by the Bolivian government. Therefore, a water balance model was implemented for the Lake Titicaca - Río Desaguadero - Lake Poopó - Salar de Coipasa (TDPS) catchment, simulating several possible climatic scenarios. Mines were identified and associated water withdrawals were extrapolated using available processing water consumption data. Long-term climatic trends, as averaged between 1970 and 2010 were used to assess the recovery prospects of the lake. Mining was found to have a very limited impact on water quantity in Lake Poopó, with total mining water withdrawals accounting for 0.2% to 0.4% of the total amount of water flowing into the lake from the Desaguadero River, reduced by only 1%. However, 1998 El Niño-induced drought conditions were found to cause a net yearly reduction in storage of 0.76 m. Under such climatic constraints, it was obtained that 32 months were needed for the lake to dry out from its height of 1.972 m as observed on the 10th of April 2013 and 38 months

  18. Drivers of methane uptake by montane forest soils in the Peruvian Andes

    Science.gov (United States)

    Jones, Sam; Diem, Torsten; Huaraca Quispe, Lidia; Cahuana, Adan; Meir, Patrick; Teh, Yit

    2016-04-01

    The exchange of methane between the soils of humid tropical forests and the atmosphere is relatively poorly documented. This is particularly true of montane settings where variations between uptake and emission of atmospheric methane have been observed. Whilst most of these ecosystems appear to function as net sinks for atmospheric methane, some act as considerable sources. In regions like the Andes, humid montane forests are extensive and a better understanding of the magnitude and controls on soil-atmosphere methane exchange is required. We report methane fluxes from upper montane cloud forest (2811 - 2962 m asl), lower montane cloud forest (1532 - 1786 m asl), and premontane forest (1070 - 1088 m asl) soils in south-eastern Peru. Between 1000 and 3000 m asl, mean annual air temperature and total annual precipitation decrease from 24 ° C and 5000 mm to 12 ° C and 1700 mm. The study region experiences a pronounced wet season between October and April. Monthly measurements of soil-atmosphere gas exchange, soil moisture, soil temperature, soil oxygen concentration, available ammonium and available nitrate were made from February 2011 in the upper and lower montane cloud forests and July 2011 in the premontane forest to June 2013. These soils acted as sinks for atmospheric methane with mean net fluxes for wet and dry season, respectively, of -2.1 (0.2) and -1.5 (0.1) mg CH4 m-2 d-1 in the upper montane forest; -1.5 (0.2) and -1.4 (0.1) mg CH4 m-2 d-1in the lower montane forest; and -0.3 (0.2) and -0.2 (0.2) mg CH4 m-2 d-1 in the premontane forest. Spatial variations among forest types were related to available nitrate and water-filled pore space suggesting that nitrate inhibition of oxidation or constraints on the diffusional supply of methane to methanotrophic communities may be important controls on methane cycling in these soils. Seasonality in methane exchange, with weaker uptake related to increased water-filled pore space and soil temperature during the wet

  19. Multi year aerosol characterization in the tropical Andes and in adjacent Amazonia using AERONET measurements

    Science.gov (United States)

    Pérez-Ramírez, Daniel; Andrade-Flores, Marcos; Eck, Thomas F.; Stein, Ariel F.; O'Neill, Norman T.; Lyamani, Hassan; Gassó, Santiago; Whiteman, David N.; Veselovskii, Igor; Velarde, Fernando; Alados-Arboledas, L.

    2017-10-01

    This work focuses on the analysis of columnar aerosol properties in the complex geophysical tropical region of South America within 10-20° South and 50-70° West. The region is quite varied and encompasses a significant part of Amazonia (lowlands) as well as high mountains in the Andes (highlands,∼4000 m a.s.l.). Several AERONET stations were included to study the aerosol optical characteristics of the lowlands (Rio Branco, Ji Parana and Cuiaba in Brazil and Santa Cruz in Bolivia) and the highlands (La Paz, Bolivia) during the 2000-2014 period. Biomass-burning is by far the most important source of aerosol in the lowlands, particularly during the dry season (August-October). Multi-annual variability was investigated and showed very strong burning activity in 2005, 2006, 2007 and 2010. This resulted in smoke characterized by correspondingly strong, above-average AODs (aerosol optical depths) and homogeneous single scattering albedo (SSA) across all the stations (∼0.93). For other years, however, SSA differences arise between the northern stations (Rio Branco and Ji Parana) with SSAs of ∼0.95 and the southern stations (Cuiaba and Santa Cruz) with lower SSAs of ∼0.85. Such differences are explained by the different types of vegetation burned in the two different regions. In the highlands, however, the transport of biomass burning smoke is found to be sporadic in nature. This sporadicity results in highly variable indicators of aerosol load and type (Angstrom exponent and fine mode fraction) with moderately significant increases in both. Regional dust and local pollution are the background aerosol in this highland region, whose elevation places it close to the free troposphere. Transported smoke particles were generally found to be more optical absorbing than in the lowlands: the hypothesis to explain this is the significantly higher amount of water vapor in Amazonia relative to the high mountain areas. The air-mass transport to La Paz was investigated using

  20. Asynchronous Glacial Chronologies in the Central Andes (15-40°S) and Paleoclimatic Implications

    Science.gov (United States)

    Zech, R.; Kull, C.; Kubik, P. W.; Veit, H.

    2006-12-01

    We have established glacial chronologies along a N-S transect over the Central Andes using 10Be surface exposure dating. Our results show that maximum glacial advances occurred asynchronously and reflect the varying influence and shifts of the major atmospheric circulation systems during the Late Quaternary: the tropical circulation in the north and the westerlies in the south. In Bolivia (three research areas in the Cordillera Real and the Cordillera Cochabamba, ~15°S) glacial advances could be dated to ~20 and 12 ka BP. This is in good agreement with published exposure age data from moraines in Bolivia and Peru (provided that all ages are calculated following the same scaling system). Accordingly, the maximum glaciation there probably occurred roughly synchronous to the temperature minimum of the global Last Glacial Maximum (LGM) and the lateglacial cold reversals. Strict correlation with neither the Younger Dryas in the northern hemisphere, nor the Antarctic Cold Reversal is possible due to the current systematic exposure age uncertainties (~10%). Glacier-Climate-Modelling corroborates the sensitivity of the reconstructed glaciers to temperature changes, rather than precipitation. On the contrary, there is good evidence for the dominant role of precipitation changes on the glacial chronologies in the lee of the Cordillera Occidental, i.e. on the Altiplano and further south. The pronounced lateglacial wet phase, which is well documented in lake transgression phases as far south as 28°S (-> tropical moisture source), seems to have caused glacial advances even at ~30°S. In two research areas in Chile at that latitude, we were able to date several lateglacial moraines. Besides, the maximum datable glaciation there occurred at ~30 ka BP. That is significantly earlier than the LGM (sensu strictu) and points to favourable climate conditions for glaciation at that time (particularly increased precipitation). We conclude that the westerlies were more intensive or

  1. Eocene extensional exhumation of basement and arc rocks along southwesternmost Peru, Central Andes.

    Science.gov (United States)

    Noury, Mélanie; Bernet, Matthias; Sempéré, Thierry

    2014-05-01

    The overthickened crust of the current Central Andes is commonly viewed as the result of tectonic shortening. However, in the present-day terrestrial forearc and arc of southwesternmost Peru, crustal thickness increases from 30 km along the coastline to >60 km below the active arc, whereas the upper crust exhibits little to no evidence of crustal shortening and, in constrast, many extensional features. How (and when) crustal overthickness was acquired in this region is thus little understood. Because crustal overthickening often results in extensional collapse and/or significant erosion, here we address this issue through a regional-scale study of exhumation using fission-track thermochronology. The limited fission-track data previously available in the area suggested that exhumation began during the Mesozoic. In this study, we present new apatite and zircon fission-track data obtained along the current terrestrial forearc of southwesternmost Peru. This relatively restricted area presents the interest of providing extensive outcrops of Precambrian to Ordovician basement and Early Jurassic to Late Cretaceous arc plutons. In order to compare the chronology of exhumation of these units, we performed extensive sampling for fission-track dating, as well as structural mapping. Our results indicate that the basement rocks and Jurassic plutons that crop out in the Arequipa region, where the crust is now >50 km-thick, experienced a rapid cooling through the 240-110°C temperature range between ~65 and ~35 Ma. This period of rapid exhumation coincided in time with the accumulation of terrestrial forearc deposits (the Lower Moquegua Group), that exhibit many syn-sedimentary extensional features and are bounded by conspicuous normal faults, specifically along the region where intense activity of the main arc between ~90 and ~60 Ma had led to voluminous magma emplacement. This close succession of (1) intense magmatic activity and (2) regional-scale exhumation associated with

  2. Paleoclimatic reconstruction in the Bolivian Andes from oxygen isotope analysis of lake sediment cellulose

    International Nuclear Information System (INIS)

    Wolfe, B.B.; Aravena, R.; Gibson, J.J.; Abbott, M.B.; Seltzer, G.O.

    2002-01-01

    Cellulose-inferred lake water δ 18 O (δ 18 O lw ) records from Lago Potosi, a seasonally-closed lake in a watershed that is not currently glaciated, and Lago Taypi Chaka Kkota, an overflowing lake in a glaciated watershed, provide the basis for late Pleistocene and Holocene paleoclimatic reconstruction in the Bolivian Andes. Deconvolution of the histories of changing evaporative isotopic enrichment from source water δ 18 O in the lake sediment records is constrained by comparison to the Sajama ice core oxygen isotope profile. At Lago Potosi, the δ 18 O lw record appears to be dominantly controlled by evaporative 18 O-enrichment, reflecting shifts in local effective moisture. Using an isotope-mass balance model, a preliminary quantitative reconstruction of summer relative humidity spanning the past 11,500 cal yr is derived from the Lago Potosi Π 18 O lw record. Results indicate that the late Pleistocene was moist with summer relative humidity values estimated at 10-20% greater than present. Increasing aridity developed in the early Holocene with maximum prolonged dryness spanning 7500 to 6000 cal yr BP at Lago Potosi, an interval characterized by summer relative humidity values that may have been 20% lower than present. Highly variable but dominantly arid conditions persist in the mid- to late Holocene, with average summer relative humidity values estimated at 15% below present, which then increase to about 10-20% greater than present by 2000 cal yr BP. Slightly more arid conditions characterize the last millennium with summer relative humidity values ranging from 5-10% lower than present. Similar long-term variations are evident in the Lago Taypi Chaka Kkota δ 18 O lw profile, except during the early Holocene when lake water evaporative 18 Oenrichment in response to low relative humidity appears to have been offset by enhanced inflow from 18 O-depleted snowmelt or groundwater from the large catchment. Close correspondence occurs between the isotope

  3. Cloud forest restoration for erosion control in a Kichwa community of the Ecuadorian central Andes Mountains

    Science.gov (United States)

    Backus, L.; Giordanengo, J.; Sacatoro, I.

    2013-12-01

    The Denver Professional Chapter of Engineers Without Borders (EWB) has begun conducting erosion control projects in the Kichwa communities of Malingua Pamba in the Andes Mountains south of Quito, Ecuador. In many high elevation areas in this region, erosion of volcanic soils on steep hillsides (i.e., food crops. Following a 2011 investigation of over 75 erosion sites, the multidisciplinary Erosion Control team traveled to Malingua Pamba in October 2012 to conduct final design and project implementation at 5 sites. In partnership with the local communities, we installed woody cloud forest species, grass (sig-sig) contour hedges, erosion matting, and rock structures (toe walls, plunge pools, bank armoring, cross vanes, contour infiltration ditches, etc.) to reduce incision rates and risk of slump failures, facilitate aggradation, and hasten revegetation. In keeping with the EWB goal of project sustainability, we used primarily locally available resources. High school students of the community grew 5000 native trees and some naturalized shrubs in a nursery started by the school principal, hand weavers produced jute erosion mats, and rocks were provided by a nearby quarry. Where possible, local rock was harvested from landslide areas and other local erosion features. Based on follow up reports and photographs from the community and EWB travelers, the approach of using locally available materials installed by the community is successful; plants are growing well and erosion control structures have remained in place throughout the November to April rainy season. The community has continued planting native vegetation at several additional erosion sites. Formal monitoring will be conducted in October 2013, followed by analysis of data to determine if induced meandering and other low-maintenance erosion control techniques are working as planned. For comparison of techniques, we will consider installing check dams in comparable gullies. The October 2013 project will also

  4. Monitoring rock glacier dynamics and ground temperatures in the semiarid Andes (Chile, 30°S)

    Science.gov (United States)

    Brenning, Alexander; Azócar, Guillermo F.; Bodin, Xavier

    2013-04-01

    Rock glaciers and mountain permafrost are widespread in the high semiarid Andes of Chile, where they concentrate greater amounts of ice than glaciers. Rock glaciers are of particular interest because in some cases the permafrost they contain might be in a degrading in response to climatic warming. This could result in increased dynamics and even to destabilization, which has been observed on some rock glaciers in the studied area. Displacement rates and active-layer temperatures of two rock glaciers as well as ground surface temperatures of the periglacial environment in the upper Elqui valley have been monitored since summer 2009/10 with funding from the Chilean Dirección General de Aguas. Differential GPS measurements of 115 points on the surface of two rock glaciers since April 2010 showed horizontal displacements of up to 1.3 m/a on the Llano de las Liebres rock glacier and up to 1.2 m/a on the Tapado rock glacier. General velocity patterns are consistent with the morphological evidence of activity (e.g., front slopes, looseness of debris) and for the Tapado complex, a clearly distinct activity from the debris-covered glacier was observed. Temperature measurements in four boreholes indicate active-layer depths of about 2.5 m at the highest locations on the Tapado rock glacier (~4400 m a.s.l.) and about 8 m near the front of the Llano rock glacier (3786 m a.s.l.). Spatial patterns of mean ground surface temperature (MGST) were analyzed with regards to influences of elevation, potential incoming solar radiation, location on ice-debris landforms (rock and debris-covered glaciers), and snow cover duration using linear mixed-effects models. While accounting for the other variables, sites with long-lasting snow patches had ~0.4°C lower MGST, and ice-debris landforms had ~0.4-0.6°C lower MGST than general debris surfaces, highlighting important local modifications to the general topographic variation of ground thermal conditions.

  5. An InSAR-based survey of volcanic deformation in the central Andes

    Science.gov (United States)

    Pritchard, M. E.; Simons, M.

    2004-02-01

    We extend an earlier interferometric synthetic aperture radar (InSAR) survey covering about 900 remote volcanos of the central Andes (14°-27°S) between the years 1992 and 2002. Our survey reveals broad (10s of km), roughly axisymmetric deformation at 4 volcanic centers: two stratovolcanoes are inflating (Uturuncu, Bolivia, and Hualca Hualca, Peru); another source of inflation on the border between Chile and Argentina is not obviously associated with a volcanic edifice (here called Lazufre); and a caldera (Cerro Blanco, also called Robledo) in northwest Argentina is subsiding. We explore the range of source depths and volumes allowed by our observations, using spherical, ellipsoidal and crack-like source geometries. We further examine the effects of local topography upon the deformation field and invert for a spherical point-source in both elastic half-space and layered-space crustal models. We use a global search algorithm, with gradient search methods used to further constrain best-fitting models. Inferred source depths are model-dependent, with differences in the assumed source geometry generating a larger range of accepted depths than variations in elastic structure. Source depths relative to sea level are: 8-18 km at Hualca Hualca; 12-25 km for Uturuncu; 5-13 km for Lazufre, and 5-10 km at Cerro Blanco. Deformation at all four volcanoes seems to be time-dependent, and only Uturuncu and Cerro Blanco were deforming during the entire time period of observation. Inflation at Hualca Hualca stopped in 1997, perhaps related to a large eruption of nearby Sabancaya volcano in May 1997, although there is no obvious relation between the rate of deformation and the eruptions of Sabancaya. We do not observe any deformation associated with eruptions of Lascar, Chile, at 16 other volcanoes that had recent small eruptions or fumarolic activity, or associated with a short-lived thermal anomaly at Chiliques volcano. We posit a hydrothermal system at Cerro Blanco to explain the

  6. Early Tertiary Exhumation, Erosion, and Sedimentation in the Central Andes, NW Argentina

    Science.gov (United States)

    Carrapa, B.; Decelles, P. G.; Gerhels, G.; Mortimer, E.; Strecker, M. R.

    2006-12-01

    Timing of deformation and resulting sedimentation patterns in the Altiplano-Puna Plateau-Eastern Cordillera of the southern Central Andes are the subject of ongoing controversial debate. In the Bolivian Altiplano, sedimentation into a foreland basin system commenced during the Paleocene. Farther south in the Puna and Eastern Cordillera of NW Argentina, a lack of data has precluded a similar interpretation. Early Tertiary non-marine sedimentary rocks are preserved within the present day Puna Plateau and Eastern Cordillera of NW Argentina. The Salar de Pastos Grandes basin in the Puna Plateau contains more than 2 km of Eocene alluvial and fluvial strata in the Geste Formation, deposited in close proximity to orogenic source terrains. Sandstone and conglomerate petrographic data document Ordovician quartzites and minor phyllites and schists as the main source rocks. Detrital zircon U-Pb ages from both the Geste Formation and from underlying Ordovician quartzite cluster in the 900-1200 Ma (Grenville) and late Precambrian-Cambrian (Panafrican) ranges. Sparse late Eocene (~37-34 Ma) grains are also present; their large size, euhedral shape, and decreasing mean ages upsection suggest that these grains are volcanogenic (i.e. ash fall contamination), derived from an inferred magmatic arc to the west. The Eocene ages corroborate mammalian paleontological dates, defining the approximate begin of deposition of the Geste Formation. Alternatively, these young zircons could be of plutonic origin; however, no Eocene plutons are present in the surrounding source rocks and this interpretation is not likely. From W to E, fluvial rocks of the Quebrada de los Colorados Formation show similar sedimentological features as those observed for the Geste Formation, suggesting a genetic link between the two. Detrital zircon U-Pb data show mainly Panafrican ages, with sparse ages in the 860-935 Ma range and a few mid-Proterozoic ages. More importantly, a significant number of late Eocene

  7. Evaluating sourcing and fluvial integration of plant wax biomarkers from the Peruvian Andes to Amazonian lowlands

    Science.gov (United States)

    Wu, M. S.; Feakins, S. J.; Ponton, C.; West, A. J.; Galy, V.

    2017-12-01

    The carbon and hydrogen isotopic compositions (respectively δ13C and δD) of plant wax biomarkers have been widely used to reconstruct past climate and environment. To understand how leaf waxes are sourced within a river catchment, and how their isotopic signature is transferred from source to sink, we study δ13C and δD of C29 n-alkanes and C30 n-alkanoic acids in the Madre de Dios River catchment along the eastern flank of the Peruvian Andes. We sampled soils across a 3.5km elevation transect and find gradients in δ13Cwax (ca. +1.5‰/km) and δDwax (ca. -10 ‰/km) similar to gradients in tree canopy leaves (Feakins et al., 2016 GCA; Wu et al., 2017 GCA). We also collected river suspended sediment samples along the Madre de Dios River and its tributaries, which together drain an area of 75,400 km2 and 6 km of elevation. We utilize soil data and a digital elevation model to construct isoscapes, delineate catchments for each river sampling location, predict river values assuming spatial uniform integration, and compare our predictions with observed values. Although both compounds generally follow isotopic gradients defined by catchment elevations, the dual isotope and compound-class comparison reveals additional processes. For C30 n-alkanoic acid we find an up to 1km lower-than-expected catchment signal, indicating degradation of upland contributions in transit and replacement with lowland inputs. In contrast, mountain-front river locations are susceptible to upland-biases (up to 1km higher sourcing) in C29 n-alkane sourcing, likely due to enhanced erosion and higher leaf wax stock in Andean soil compared to the lowland, and greater persistence of n-alkanes than n-alkanoic acids. For both compounds, the bias is eliminated with several hundred km of river transit across the floodplain. In one location, we identify significant petrogenic contamination of n-alkanes but not n-alkanoic acids. These results indicate the power in combining dual compound classes and

  8. The Real of Community, the Desire for Development and the Performance of Egalitarianism in the Peruvian Andes: A Materialist–Utopian Account

    NARCIS (Netherlands)

    Vries, de P.A.

    2015-01-01

    The paper proposes a materialist–utopian perspective for explaining the persistence of community in the Andes by drawing upon Lacanian theory and the thought of the Peruvian Marxist José Carlos Mariátegui. What characterizes the Andean comunidad are not notions of belonging and identity, but the

  9. Killing the snake of poverty : local perceptions of poverty and well-being and people’s capabilities to improve their lives in the Southern Andes of Peru

    NARCIS (Netherlands)

    Miyashita, A.

    2009-01-01

    Despite the generalised image of comuneros of the Southern Andes of Peru as living in poverty, a closer examination of the daily lives of the campesinos provides a more dynamic perspective. Some households claim that their lives are improving, others that their lives are the same, while many report

  10. Mallas y flujos : acción colectiva, cambio social, quinua y desarrollo regional indígena en los Andes Bolivianos

    NARCIS (Netherlands)

    Laguna, P.

    2011-01-01

    This thesis studies collective action and social change in indigenous rural organisations (IRO) in the Bolivian Andes. I focus on the effects and importance that these organisations have in the historical process of regional development as social spaces that encapsulate different projects of

  11. The ethno-politics of water security: contestations of ethnicity and gender in strategies to control water in the Andes of Peru

    NARCIS (Netherlands)

    Vera-Delgado, J.

    2011-01-01

    This thesis is the result of a multidisciplinary research which tries to explain water injustices and the threats to water rights access and control experienced by indigenous peasants of the Peruvian Andes. It attempts to contribute to the analysis of the interactions between ethnicity and

  12. Phytogeography of the vascular páramo flora of Ramal de Guaramacal (Andes, Venezuela) and its ties to other páramo floras

    NARCIS (Netherlands)

    Cuello, N.L.; Cleef, A.M.; Aymard, G.

    2010-01-01

    Ramal de Guaramacal is an outlier and lower elevation mountain range located at the northeastern end of the Venezuelan Andes. Phytogeographical patterns and affinities of the low altitude and wet vascular páramo flora of Ramal de Guaramacal, have been studied with emphasis in to the analysis of the

  13. The Neogene rise of the tropical Andes facilitated diversification of wax palms (Ceroxylon: Arecaceae) through geographic colonization and climatic niche separation

    NARCIS (Netherlands)

    Sanín, M.J.; Kissling, W.D.; Bacon, C.D.; Borchsenius, F.; Galeano, G.; Svenning, J.-C.; Olivera, J.; Ramírez, R.; Trénel, P.; Pintaud, J.-C.

    2016-01-01

    The tropical Andes are a biodiversity hotspot, partly due to their rich and complex floristic composition. A fundamental question regarding this outstanding biodiversity is what role the Andean orogeny has played in species diversification. Ceroxylon is a genus of endemic Andean palms that stands

  14. Astronomical tuning of long pollen records reveals the dynamic history of montane biomes and lake levels in the tropical high Andes during the Quaternary

    NARCIS (Netherlands)

    Torres, V.; Hooghiemstra, H.; Lourens, L.; Tzedakis, P.C.

    2013-01-01

    Long pollen records from two sediment cores of the basin of Bogotá (Colombia) are presented, reflecting the dynamic history of environmental and vegetation changes in the tropical high Andes during the Quaternary. An astronomically tuned age model has been developed by using the visual correlation

  15. Virus-Vectored Influenza Virus Vaccines

    Science.gov (United States)

    Tripp, Ralph A.; Tompkins, S. Mark

    2014-01-01

    Despite the availability of an inactivated vaccine that has been licensed for >50 years, the influenza virus continues to cause morbidity and mortality worldwide. Constant evolution of circulating influenza virus strains and the emergence of new strains diminishes the effectiveness of annual vaccines that rely on a match with circulating influenza strains. Thus, there is a continued need for new, efficacious vaccines conferring cross-clade protection to avoid the need for biannual reformulation of seasonal influenza vaccines. Recombinant virus-vectored vaccines are an appealing alternative to classical inactivated vaccines because virus vectors enable native expression of influenza antigens, even from virulent influenza viruses, while expressed in the context of the vector that can improve immunogenicity. In addition, a vectored vaccine often enables delivery of the vaccine to sites of inductive immunity such as the respiratory tract enabling protection from influenza virus infection. Moreover, the ability to readily manipulate virus vectors to produce novel influenza vaccines may provide the quickest path toward a universal vaccine protecting against all influenza viruses. This review will discuss experimental virus-vectored vaccines for use in humans, comparing them to licensed vaccines and the hurdles faced for licensure of these next-generation influenza virus vaccines. PMID:25105278

  16. Viruses infecting reptiles.

    Science.gov (United States)

    Marschang, Rachel E

    2011-11-01

    A large number of viruses have been described in many different reptiles. These viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. Interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. Interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. The impact of many viral infections on reptile health is not known. Koch's postulates have only been fulfilled for a limited number of reptilian viruses. As diagnostic testing becomes more sensitive, multiple infections with various viruses and other infectious agents are also being detected. In most cases the interactions between these different agents are not known. This review provides an update on viruses described in reptiles, the animal species in which they have been detected, and what is known about their taxonomic positions.

  17. Viruses Infecting Reptiles

    Directory of Open Access Journals (Sweden)

    Rachel E. Marschang

    2011-11-01

    Full Text Available A large number of viruses have been described in many different reptiles. These viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. Interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. Interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. The impact of many viral infections on reptile health is not known. Koch’s postulates have only been fulfilled for a limited number of reptilian viruses. As diagnostic testing becomes more sensitive, multiple infections with various viruses and other infectious agents are also being detected. In most cases the interactions between these different agents are not known. This review provides an update on viruses described in reptiles, the animal species in which they have been detected, and what is known about their taxonomic positions.

  18. Tectogénesis, orogénesis y volcanismo en los Andes del Sur del Perú

    Directory of Open Access Journals (Sweden)

    1975-01-01

    Full Text Available Dans le Sud du Pérou, les plissements andins (tectogenèse n'ont pas été générateurs de reliefs importants, alors que les mouvements épéirogéniques ont véritablement créé le relief des Andes (orogenèse et ont donné lieu à un volcanisme d'une puissance considérable. Du point de vue géomorphologique, les structures mises en place par les mouvements tangentiels andins ont cessé de s'exprimer topographiquement vers le milieu du Miocène par suite de l'aplanissement général de la région (surface de la Puna. De même, les reliefs importants créés par les mouvements épéirogéniques et les accumulations volcaniques qui les accompagnaient (Volcanisme Toquepala de l'Eocène et Volcanisme Tacaza de l'Oligo-Miocène, ont été complètement arasés. Dans ces conditions, l'essentiel du volume actuel des Andes fut l’œuvre de l'orogenèse et du volcanisme des 15 derniers millions d'années. La mise en place s'est effectuée en deux étapes. La première a commencé par des accumulations ignimbritiques (Formation Huaylillas qui ont fossilisé la surface d'aplanissement dans tout le Sud du Pérou. Ce volcanisme fissural correspondait au début d'une période de distension qui se traduisit par le soulèvement des Andes à la fin du Miocène. Apres une courte interruption (pendant laquelle il faut placer une phase de compression au cours du Pliocène, la deuxième étape a été marquée par le soulèvement de toute la région, zone côtière comprise. Le début de cette nouvelle phase de distension a donné lieu à des émissions ignimbritiques et pyroclastiques (Formation Maure, Sillar, Formations Sencca et Capillune dont les produits ont comblé les bassins d'érosion résultant du rajeunissement de la surface de la Puna. Par la suite, à mesure que le soulèvement a pris de l'ampleur (Pléistocène, le volcanisme a changé de caractère, et, sur la couverture d'ignimbrites et de pyroclastites, la construction de grands strato

  19. Cold episodes in the Peruvian Central Andes: Composites, Types, and their Impacts over South America (1958-2014)

    Science.gov (United States)

    Sulca, J. C.; Vuille, M. F.; Roundy, P. E.; Trasmonte, G.; Silva, Y.; Takahashi, K.

    2015-12-01

    The Mantaro basin (MB) is located in the central Peruvian Andes. Occasionally, cold episodes are observed during austral summer (January-March), that strongly damage crops. However, little is known about the causes and impacts of such cold episodes. The main goal of this study is thus to characterize cold episodes in the MB and assess their large-scale circulation and teleconnections over South America (SA) during austral summer. To identify cold events in the MB daily minimum temperature (Tmin) for the period 1958-2014 from Huayao station, located within the MB was used. A cold episode is defined when daily minimum temperature drops below its 10-percentile for at least one day. Additionally, to study the sensitivity between physical mechanisms associated with cold episodes and temperature, cold episodes are classified in three groups: Weak cold episodes (7.5 ≤ Tmin ≤ 10 percentile), strong cold episodes (Tmin ≤ 2.5 percentile), but excluding the 9 coldest events (Tmin ≤ 0 ͦ C), henceforth referred to as extraordinary cold episodes. Several gridded reanalysis were used to characterize the large-scale circulation, cloud cover and rainfall over SA associated with these events. Weak and strong cold episodes in the MB are mainly associated with a weakening of the Bolivian High-Nordeste Low system by tropical-extratropical interactions. Both types of cold episodes are associated with westerly wind anomalies at mid- and upper-tropospheric levels aloft the Peruvian Central Andes, which inhibit the influx of humid air masses from the lowlands to the east and hence limit the development of cloud cover (e.g., positive OLR anomalies over MB). The resulting clear sky conditions cause nighttime temperatures to drop, leading to cold extremes below 10-percentile. Simultaneously, northeastern Brazil (NEB) registers negative OLR anomalies, strong convection and enhanced cloud cover because displacement of the South Atlantic Convergence Zone (SACZ) toward the northeast of

  20. Cosmogenic 10Be Dating of Early and Latest Holocene Moraines on Nevado Salcantay in the Southern Peruvian Andes

    Science.gov (United States)

    Licciardi, J. M.; Schaefer, J. M.; Lund, D. C.

    2007-12-01

    A two-fold sequence of nested lateral and end moraines was mapped in a glacial trough emanating from the southwest flank of Nevado Salcantay (6271 m; ~13°S latitude), the highest peak in the Cordillera Vilcabamba of southern Peru. The field area is situated 25 km due south of the archaeological site of Machu Picchu. Outer and inner moraines in the sequence were deposited by valley glaciers that terminated ~5 km and ~3 km, respectively, from their headwall on the Salcantay summit massif. Cosmogenic 10Be surface exposure dating of granitic boulders sampled on the Salcantay moraines is underway and has provided the first numerical ages for these deposits. Initial results indicate ages of 8.1 ± 0.1 10Be ka for the outer moraine and 200 ± 20 10Be years for the sharp-crested inner moraine. These ages are derived using the CRONUS-Earth 10Be exposure age calculator (version 2.0) and expressed with respect to the Lal- Stone production rate scaling scheme using the standard atmosphere. The outer and inner moraine ages correspond to glacial events during the early and latest Holocene, respectively. Further 10Be dating of the mapped moraines and similar deposits observed in adjacent drainages on Nevado Salcantay is anticipated to yield a high-resolution chronology of valley glaciation in this segment of the southern Peruvian Andes. The new results bridge an important gap between existing Andean glacier records to the north and south, and complement available ice core and lacustrine paleoclimate records in the vicinity, thereby expanding spatial and temporal coverage for identifying patterns of Holocene climate change in the tropical Andes. Notably, the inner moraine age correlates with the timing of the Little Ice Age as defined in northern mid- and high latitude glacier records, and suggests considerable expansion of valley glaciers in the southern Peruvian Andes during this climatic minimum. Apart from their paleoclimatic significance, the initial results also demonstrate

  1. Altitudinal vegetation belts in the high-Andes of central Chile (33°S Pisos altitudinales de vegetación en los Andes de Chile central (33°S

    Directory of Open Access Journals (Sweden)

    Lohengrin A. Cavieres

    2000-06-01

    Full Text Available The limits of alpine vegetation belts have been established mainly based on physiognomic criteria. However, a more objective approach for fixing limits of vegetation belts are methods based on species composition and relative abundance of each species. While these methods are more time consuming, they are more detailed and permit the detection of physical factors affecting the limits of vegetation belts. In this paper we: 1 describe the altitudinal changes of vegetation above timberline, 2 compare vegetation belts defined with physiognomy and two floristic methods (a qualitative one based on altitudinal changes in species composition, and a quantitative one based on changes in dominant species; and 3 detect some environmental factors responsible for the altitudinal distribution of alpine vegetation between 2100 and 3700 masl in the Andes of Santiago, central Chile (33°S. There was a complete agreement between the different methods in delimiting the subalpine belt. However, in the lower alpine belt (the cushion's belt floristic methods subdivided it in 2-3 sub-belts. In the floristic methods, elevations 3500-3700 that formed the higher alpine belt segregated in separate ways because they have no species in common. Physiognomic descriptions lose relevant information about species distribution, especially at higher elevations. Mean annual temperature and nitrogen content of soil are the main environmental factors affecting the altitudinal limits of vegetation belts in the central Chilean AndesLa delimitación de los pisos altitudinales de vegetación andina se ha basado principalmente en criterios fisionómicos. Sin embargo, un criterio más objetivo para la delimitación es usar métodos basados en la composición y abundancia relativa de las especies presentes. Mientras estos métodos requieren de un mayor esfuerzo de muestreo, son más detallados y permiten detectar factores físicos involucrados en la delimitación altitudinal de la vegetaci

  2. Preliminary Depositional and Provenance Records of Mesozoic Basin Evolution and Cenozoic Shortening in the High Andes, La Ramada Fold-Thrust Belt, Southern-Central Andes (32-33°S)

    Science.gov (United States)

    Mackaman-Lofland, C.; Horton, B. K.; Fuentes, F.; Constenius, K. N.; McKenzie, R.; Alvarado, P. M.

    2015-12-01

    The Argentinian Andes define key examples of retroarc shortening and basin evolution above a zone of active subduction. The La Ramada fold-thrust belt (RFTB) in the High Andes provides insights into the relative influence and temporal records of diverse convergent margin processes (e.g. flat-slab subduction, convergent wedge dynamics, structural inversion). The RFTB contains Mesozoic extensional basin strata deformed by later Andean shortening. New detrital zircon U-Pb analyses of Mesozoic rift sediments reveal: (1) a dominant Permo-Triassic age signature (220-280 Ma) associated with proximal sources of effective basement (Choiyoi Group) during Triassic synrift deposition; (2) upsection younging of maximum depositional ages from Late Triassic through Early Cretaceous (230 to 100 Ma) with the increasing influence of western Andean arc sources; and (3) a significant Late Cretaceous influx of Paleozoic (~350-550 Ma) and Proterozoic (~650-1300 Ma) populations during the earliest shift from back-arc post-extensional subsidence to upper-plate shortening. The Cenozoic detrital record of the Manantiales foreland basin (between the Frontal Cordillera and Precordillera) records RFTB deformation prior to flat-slab subduction. A Permo-Triassic Choiyoi age signature dominates the Miocene succession, consistent with sources in the proximal Espinacito range. Subordinate Mesozoic (~80-250 Ma) to Proterozoic (~850-1800 Ma) U-Pb populations record exhumation of the Andean magmatic arc and recycling of different structural levels in the RFTB during thrusting/inversion of Mesozoic rift basin strata and subjacent Paleozoic units. Whereas maximum depositional ages of sampled Manantiales units cluster at 18-20 Ma, the Estancia Uspallata basin (~50 km to the south) shows consistent upsection younging of Cenozoic populations attributed to proximal volcanic centers. Ongoing work will apply low-temperature thermochronology to pinpoint basin accumulation histories and thrust timing.

  3. Zika virus disease

    Directory of Open Access Journals (Sweden)

    Adel I Al-Afaleq

    2017-01-01

    Full Text Available The Zika virus is an arbovirus belonging to the virus family Flaviviridae. The virus was isolated in 1947 from a rhesus monkey in the Zika Forest of Uganda. The virus causes sporadic mild human infections in Africa and later in Asia. However, by 2007 a major shift in its infection pattern was noticed and thousands of human infections were reported in the State of Yap and Federated States of Micronesia. In the last 3 years, major outbreaks have continued to occur and the virus has spread to several Pacific and American countries. These outbreaks were mostly asymptomatic; however, there were more severe clinical signs associated with the infections. Those signs included microcephaly and Guillain–Barre syndrome. It is believed that various species of mosquitoes can biologically transmit the virus. However, Aedes aegypti is most widely associated with the Zika virus. Recently, new modes of virus transmission have been reported, including mother-to-fetus, sexual, blood transfusion, animal bites, laboratory exposure and breast milk. Differential diagnosis is very important as some other arboviruses such as yellow fever virus, West Nile virus, dengue virus, and chikungunya virus have similar clinical manifestations to the Zika virus infection as well as relating serologically to some of these viruses. Established laboratory diagnostic tests to detect the Zika virus are limited, with reverse transcription polymerase chain reaction being the most widely used test. Taking into consideration the quickness of the spread of infection, size of the infected population and change of the infection severity pattern, the Zika virus infection merits collective efforts on all levels to prevent and control the disease. Limited research work and data, concurrent infection with other arboviruses, involvement of biological vectors, mass crowd events, human and trade movements and lack of vaccines are some of the challenges that we face in our efforts to prevent and

  4. An integrative water balance model framework for a changing glaciated catchment in the Andes of Peru

    Science.gov (United States)

    Drenkhan, Fabian; Huggel, Christian; García Hernández, Javier; Fluixá-Sanmartín, Javier; Seidel, Jochen; Muñoz Asmat, Randy

    2017-04-01

    In the Santa River catchment [SRC] (Cordillera Blanca, Andes of Peru), human livelihoods strongly depend on year-round streamflow from glaciers and reservoirs, particularly in the dry season and in adjacent arid lowlands. Perennial glacial streamflow represents a buffer to water shortages, annual discharge variability and river contamination levels. However, climate change impacts, consecutive glacier shrinkage as well as new irrigated agriculture and hydropower schemes, population growth and thus water allocation might increase water scarcity in several areas of the SRC. This situation exerts further pressure and conflict potential over water resources and stresses the need to analyze both water supply and demand trends in a multidisciplinary and interlinked manner. In this context, an integrative glacio-hydrological framework was developed based on the Glacier and Snow Melt (GSM) and SOil CONTribution (SOCONT) models using the semi-distributed free software RS MINERVE. This water balance model incorporates hydroclimatic, socioeconomic and hydraulic objects and data at daily scale (with several gaps) for the last 50 years (1965-2015). A particular challenge in this context represents the poor data availability both in quantity and quality. Therefore, the hydroclimatic dataset to be used had to be carefully selected and data gaps were filled applying a statistical copula-based approach. The socioeconomic dataset of water demand was elaborated using several assumptions based on further census information and experiences from other projects in the region. Reservoirs and hydropower models were linked with additional hydraulic data. In order to increase model performance within a complex topography of the 11660 km2 SRC, the area was divided into 22 glaciated (GSM) and 42 non-glaciated (SOCONT) subcatchment models. Additionally, 382 elevation bands at 300 m interval were created and grouped into 22 different calibration zones for the whole SRC. The model was calibrated

  5. Summer energy balance and ablation of high elevation glaciers in the central Chilean Andes

    Science.gov (United States)

    Brock, Benjamin; Rivera, Andres; Burger, Flavia; Bravo, Claudio

    2014-05-01

    Glaciers of the semi-arid central Chilean Andes are an important freshwater source for the populous Central Valley region of Chile, but have been shrinking in recent decades. The surface energy balance of these glaciers is of high scientific interest as summer ablation occurs through both sublimation and melt. During the 2012-13 Austral Summer a glacio-meteorological monitoring programme was established on Olivares Alfa (3.9 km2, 4130-4800 m elevation) and Beta (8.3 km2, 3620-4850 m elevation) Glaciers and their forelands in the Upper Olivares Valley, 33°00'-33°11' S, 70°05'-70°15' W, approximately 50 km north-east of Santiago. This included complete automatic weather stations (AWSs) with sonic rangers to record surface ablation on the ablation zones of the two glaciers, and one AWS in the proglacial area of Olivares Alfa Glacier including precipitation gauge. To complement these point data, daily images of the glaciers were captured with fixed cameras in order to calculate snow cover and albedo distributions. To calculate the surface energy balance and rates of melt and sublimation, a model was developed which uses direct AWS measurements of the radiative fluxes and calculates the turbulent fluxes of sensible and latent heat using the bulk aerodynamic approach. The model also calculates the subsurface heat flux and includes a simple scheme to estimate refreezing of melt water within surface snow or ice. Meteorological data and model results for the December to May period will be presented in this paper. Model calculations match closely the cumulative ablation curve of the sonic ranger at Olivares Alfa, with a slight overestimation, and overestimate cumulative ablation recorded by the sonic ranger at Olivares Beta, possibly due, at least in part, to uncertain snow density values. Modelled cumulative ablation in the December-April period is 2.2 m water equivalent (w.e.) at Olivares Alfa (0.10 m sublimation, 2.10 m melt) and 2.34 m w.e. at Olivares Beta (0.18 m

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

    Science.gov (United States)

    Bahlburg, H.; Breitkreuz, C.

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

  7. Amazon River dissolved load: temporal dynamics and annual budget from the Andes to the ocean.

    Science.gov (United States)

    Moquet, Jean-Sébastien; Guyot, Jean-Loup; Crave, Alain; Viers, Jérôme; Filizola, Naziano; Martinez, Jean-Michel; Oliveira, Tereza Cristina; Sánchez, Liz Stefanny Hidalgo; Lagane, Christelle; Casimiro, Waldo Sven Lavado; Noriega, Luis; Pombosa, Rodrigo

    2016-06-01

    The aim of the present study is to estimate the export fluxes of major dissolved species at the scale of the Amazon basin, to identify the main parameters controlling their spatial distribution and to identify the role of discharge variability in the variability of the total dissolved solid (TDS) flux through the hydrological cycle. Data are compiled from the monthly hydrochemistry and daily discharge database of the "Programa Climatologico y Hidrologico de la Cuenca Amazonica de Bolivia" (PHICAB) and the HYBAM observatories from 34 stations distributed over the Amazon basin (for the 1983-1992 and 2000-2012 periods, respectively). This paper consists of a first global observation of the fluxes and temporal dynamics of each geomorphological domain of the Amazon basin. Based on mean interannual monthly flux calculations, we estimated that the Amazon basin delivered approximately 272 × 10(6) t year(-1) (263-278) of TDS during the 2003-2012 period, which represents approximately 7 % of the continental inputs to the oceans. This flux is mainly made up by HCO3, Ca and SiO2, reflecting the preferential contributions of carbonate and silicate chemical weathering to the Amazon River Basin. The main tributaries contributing to the TDS flux are the Marañon and Ucayali Rivers (approximately 50 % of the TDS production over 14 % of the Amazon basin area) due to the weathering of carbonates and evaporites drained by their Andean tributaries. An Andes-sedimentary area-shield TDS flux (and specific flux) gradient is observed throughout the basin and is first explained by the TDS concentration contrast between these domains, rather than variability in runoff. This observation highlights that, under tropical context, the weathering flux repartition is primarily controlled by the geomorphological/geological setting and confirms that sedimentary areas are currently active in terms of the production of dissolved load. The log relationships of concentration vs discharge have

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

    Science.gov (United States)

    Suarez, M M; Torrealba, R

    1982-01-01

    studies identified that use demographic, economic, or phychosocial approaches have provided partial explanations of the current status of Andean migrations. The explanations they offer, by not transcending the current reality of the migrants, overlook the historical traits of internal migration. Migratory flows do not spring up suddenly. They result from specific socio-political circumstances which, when closely linked to demographic evidence, serve as a basis for understanding the process. Review of studies on internal migration in the Northern Andes, as presented here, reveals a series of distinguishing characteristics: there are 5 migratory patterns--rural to rural, rural to urban, urban to urban, seasonal worker migration, and return migration, and the predominant pattern has been rural to urban; the demographic data show the importance of rural migrants to urban growth in the region and a complementary loss of population in the rural areas; depopulation of the countryside has been selective; and there is a marked disparity in employment remuneration between rural and urban areas.

  9. Description of Thecavermiculatus andinus n.sp. (Meloidoderidae), a Round Cystoid Nematode from the Andes Mountains of Peru.

    Science.gov (United States)

    Golden, A M; Franco, J; Jatala, P; Astogaza, E

    1983-07-01

    Thecavermiculatus andinus n.sp. is described and illustrated from Oxalis tuberosa originally collected in the vicinity of Lake Titicaca high in the Andes mountains of southern Peru. This new species differs markedly front the other two species in the genus, especially in having a much greater female vulval-anal distance and annules with lined punctation on most of the female body with a lacelike pattern restricted to the posterior portion, particularly at the vulva and anus which do not protrude. Females are essentially spherical with protruding neck, white to yellowish in color, and can easily be mistaken for potato cyst nematodes. Among the dozen or more known weed and crop host plants are potato and eggplant. In order to accommodate this new species, the genus Thecavermieulatus is emended. A key to the species of this genus is presented.

  10. A new species of the Pristimantis orestes group (Amphibia: Strabomantidae) from the high Andes of Ecuador, Reserva Mazar.

    Science.gov (United States)

    Guayasamin, Juan M; Arteaga, Alejandro F

    2013-02-21

    We describe a new Pristimantis from La Libertad and Rumiloma, Reserva Mazar, Andes of Southeastern Ecuador, at elevations between 2895-3415 m. This species is assigned to the P. orestes group, from whose members it differs by its small body size (adult males ≤ 18.1 mm; adult females ≤ 23.7 mm), usually reticulated ventral pattern, and visible tympanum. The vocalization of the new species consists of a series of calls; each call is composed by a pulsed, non-modulated note in frequency, and with a dominant frequency of 3122-3171 Hz. A molecular phylogeny based on a fragment of the mitochondrial gene 12S shows that the new species is sister to Pristimantis simonbolivari.

  11. A large and unusually colored new snake species of the genus Tantilla (Squamata; Colubridae) from the Peruvian Andes.

    Science.gov (United States)

    Koch, Claudia; Venegas, Pablo J

    2016-01-01

    A new colubrid species of the genus Tantilla from the dry forest of the northern Peruvian Andes is described on the basis of two specimens, which exhibit a conspicuous sexual dimorphism. Tantilla tjiasmantoi sp. nov. represents the third species of the genus in Peru. The new species is easily distinguished from its congeners by the combination of scalation characteristics and the unusual transversely-banded color pattern on the dorsum. A detailed description of the skull morphology of the new species is given based on micro-computed tomography images. The habitat of this new species is gravely threatened due to human interventions. Conservation efforts are urgently needed in the inter-Andean valley of the Maranon River.

  12. Mass Balance of Cenozoic Andes-Amazon Source to Sink System—Marañón Basin, Peru

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    Gérôme Calvès

    2018-05-01

    Full Text Available We investigate the mass balance of the Cenozoic Andes-Amazon source to sink system using rock uplift proxies and solid sedimentation of the Marañón Basin in Peru. The evolution of sedimentation rates is calibrated with regional structural restored cross-section. The quantification of eroded sediments from reliefs to sedimentary basin is achieved with ×10 Myr resolution and compared to present day proxies from the HYBAM (HYdrologie et Biogéochimie du Bassin Amazonien Critical Zone Observatory. Erosion of the early Andean landforms started during the Upper Mesozoic period, but sediment rates significantly increase during the Neogene. This is in agreement with the calibrated increase of rock uplift in the Andean orogenic belt.

  13. Scale of human mobility in the southern Andes (Argentina and Chile): A new framework based on strontium isotopes.

    Science.gov (United States)

    Barberena, Ramiro; Durán, Víctor A; Novellino, Paula; Winocur, Diego; Benítez, Anahí; Tessone, Augusto; Quiroga, María N; Marsh, Erik J; Gasco, Alejandra; Cortegoso, Valeria; Lucero, Gustavo; Llano, Carina; Knudson, Kelly J

    2017-10-01

    The goal of this article is to assess the scale of human paleomobility and ecological complementarity between the lowlands and highlands in the southern Andes during the last 2,300 years. By providing isotope results for human bone and teeth samples, we assess a hypothesis of "high residential mobility" suggested on the basis of oxygen isotopes from human remains. We develop an isotopic assessment of human mobility in a mountain landscape combining strontium and oxygen isotopes. We analyze bone and teeth samples as an approach to life-history changes in spatial residence. Human samples from the main geological units and periods within the last two millennia are selected. We present a framework for the analysis of bioavailable strontium based on the combination of the geological data with isotope results for rodent samples. The 87 Sr/ 86 Sr values from human samples indicate residential stability within geological regions along life history. When comparing strontium and oxygen values for the same human samples, we record a divergent pattern: while δ 18 O values for samples from distant regions overlap widely, there are important differences in 87 Sr/ 86 Sr values. Despite the large socio-economic changes recorded, 87 Sr/ 86 Sr values indicate a persisting scenario of low systematic mobility between the different geological regions. Our results suggest that strontium isotope values provide the most germane means to track patterns of human occupation of distinct regions in complex geological landscapes, offering a much higher spatial resolution than oxygen isotopes in the southern Andes. © 2017 Wiley Periodicals, Inc.

  14. Structural control on arc volcanism: The Caviahue Copahue complex, Central to Patagonian Andes transition (38°S)

    Science.gov (United States)

    Melnick, Daniel; Folguera, Andrés; Ramos, Victor A.

    2006-11-01

    This paper describes the volcanostratigraphy, structure, and tectonic implications of an arc volcanic complex in an oblique subduction setting: the Caviahue caldera Copahue volcano (CAC) of the Andean margin. The CAC is located in a first-order morphotectonic transitional zone, between the low and narrow Patagonian and the high and broad Central Andes. The evolution of the CAC started at approximately 4-3 Ma with the opening of the 20 × 15 km Caviahue pull-apart caldera; Las Mellizas volcano formed inside the caldera and collapsed at approximately 2.6 Ma; and the Copahue volcano evolved in three stages: (1) 1.2-0.7 Ma formed the approximately 1 km thick andesitic edifice, (2) 0.7-0.01 Ma erupted andesitic-dacitic subglacial pillow lavas, and (3) 0.01-0 Ma erupted basaltic-andesites and pyroclastic flows from fissures, aligned cones, and summit craters. Magma ascent has occurred along planes perpendicular to the least principal horizontal stress, whereas hydrothermal activity and hot springs also occur along parallel planes. At a regional scale, Quaternary volcanism concentrates along the NE-trending, 90 km long Callaqui-Copahue-Mandolegüe lineament, the longest of the southern volcanic zone, which is here interpreted as an inherited crustal-scale transfer zone from a Miocene rift basin. At a local scale within the CAC, effusions are controlled by local structures that formed at the intersection of regional fault systems. The Central to Patagonian Andes transition occurs at the Callaqui-Copahue-Mandolegüe lineament, which decouples active deformation from the intra-arc strike-slip Liquiñe-Ofqui fault zone to the south and the backarc Copahue-Antiñir thrust system.

  15. The Mass Elevation Effect of the Central Andes and Its Implications for the Southern Hemisphere's Highest Treeline

    Directory of Open Access Journals (Sweden)

    Wenhui He

    2016-05-01

    Full Text Available One of the highest treelines in the world is at 4810 m above sea level on the Sajama Volcano in the central Andes. The climatological cause of that exceptionally high treeline position is still unclear. Although it has been suggested that the mass elevation effect (MEE explains the upward shift of treelines in the Altiplano region, the magnitude of MEE has not yet been quantified for that region. This paper defines MEE as the air temperature difference in summer at the same elevation between the inner mountains/plateaus (Altiplano and the free atmosphere above the adjacent lowlands of the Andean Cordillera. The Altiplano air temperature was obtained from the Global Historical Climatology Network-Monthly temperature database, and the air temperature above the adjacent lowlands was interpolated based on the National Center for Environmental Prediction/National Center for Atmospheric Research Reanalysis 1 data set. We analyzed the mean air temperature differences for January, July, and the warm months from October to April. The air temperature was mostly higher on the Altiplano than over the neighboring lowlands at the same altitude. The air temperature difference increased from the outer Andean east-facing slope to the interior of the Altiplano in summer, and it increased from high latitudes to low latitudes in winter. The mean air temperature in the Altiplano in summer is approximately 5 K higher than it is above the adjacent lowlands at the same mean elevation, averaging about 3700 m above sea level. This upward shift of isotherms in the inner part of the Cordillera enables the treeline to climb to 4810 m, with shrub-size trees reaching even higher. Therefore, the MEE explains the occurrence of one of the world’s highest treelines in the central Andes.

  16. The Relative Impact of Climate Change on the Extinction Risk of Tree Species in the Montane Tropical Andes.

    Science.gov (United States)

    Tejedor Garavito, Natalia; Newton, Adrian C; Golicher, Duncan; Oldfield, Sara

    2015-01-01

    There are widespread concerns that anthropogenic climate change will become a major cause of global biodiversity loss. However, the potential impact of climate change on the extinction risk of species remains poorly understood, particularly in comparison to other current threats. The objective of this research was to examine the relative impact of climate change on extinction risk of upper montane tree species in the tropical Andes, an area of high biodiversity value that is particularly vulnerable to climate change impacts. The extinction risk of 129 tree species endemic to the region was evaluated according to the IUCN Red List criteria, both with and without the potential impacts of climate change. Evaluations were supported by development of species distribution models, using three methods (generalized additive models, recursive partitioning, and support vector machines), all of which produced similarly high AUC values when averaged across all species evaluated (0.82, 0.86, and 0.88, respectively). Inclusion of climate change increased the risk of extinction of 18-20% of the tree species evaluated, depending on the climate scenario. The relative impact of climate change was further illustrated by calculating the Red List Index, an indicator that shows changes in the overall extinction risk of sets of species over time. A 15% decline in the Red List Index was obtained when climate change was included in this evaluation. While these results suggest that climate change represents a significant threat to tree species in the tropical Andes, they contradict previous suggestions that climate change will become the most important cause of biodiversity loss in coming decades. Conservation strategies should therefore focus on addressing the multiple threatening processes currently affecting biodiversity, rather than focusing primarily on potential climate change impacts.

  17. Observational evidences on the modulation of the South American Low Level Jet east of the Andes according the ENSO variability

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    G. A. M. Silva

    2009-02-01

    Full Text Available The differences on the phase and wavelength of the quasi-stationary waves over the South America generated by El Niño (EN and La Niña (LN events seem to affect the daily evolution of the South American Low Level Jet east of the Andes (SALLJ. For the austral summer period of 1977–2004 the SALLJ episodes detected according to Bonner criterion 1 show normal to above-normal frequency in EN years, and in LN years the episodes show normal to below-normal frequency.

    During EN and LN years the SALLJ episodes were associated with positive rainfall anomalies over the La Plata Basin, but more intense during LN years. During EN years the increase in the SALLJ cases were associated to intensification of the Subtropical Jet (SJ around 30° S and positive Sea Level Pressure (SLP anomalies over the western equatorial Atlantic and tropical South America, particularly over central Brazil. This favored the intensification of the northeasterly trade winds over the northern continent and it channeled by the Andes mountain to the La Plata Basin region where negative SLP are found. The SALLJ cases identified during the LN events were weaker and less frequent when compared to those for EN years. In this case the SJ was weaker than in EN years and the negative SLP anomalies over the tropical continent contributed to the inversion of the northeasterly trade winds. Also a southerly flow anomaly was generated by the geostrophic balance due to the anomalous blocking over southeast Pacific and the intense cyclonic transient over the southern tip of South America. As result the warm tropical air brought by the SALLJ encounters the cold extratropical air from the southerly winds over the La Plata basin. This configuration can increase the conditional instability over the La Plata basin and may explain the more intense positive rainfall anomalies in SALLJ cases during LN years than in EN years.

  18. Kinematics, Exhumation, and Sedimentation of the North Central Andes (Bolivia): An Integrated Thermochronometer and Thermokinematic Modeling Approach

    Science.gov (United States)

    Rak, Adam J.; McQuarrie, Nadine; Ehlers, Todd A.

    2017-11-01

    Quantifying mountain building processes in convergent orogens requires determination of the timing and rate of deformation in the overriding plate. In the central Andes, large discrepancies in both timing and rate of deformation prevent evaluating the shortening history in light of internal or external forcing factors. Geologic map patterns, age and location of reset thermochronometer systems, and synorogenic sediment distribution are all a function of the geometry, kinematics, and rate of deformation in a fold-thrust-belt-foreland basin (FTB-FB) system. To determine the timing and rate of deformation in the northern Bolivian Andes, we link thermokinematic modeling to a sequentially forward modeled, balanced cross section isostatically accounting for thrust loads and erosion. Displacement vectors, in 10 km increments, are assigned variable ages to create velocity fields in a thermokinematic model for predicting thermochronometer ages. We match both the pattern of predicted cooling ages with the across strike pattern of measured zircon fission track, apatite fission track, and apatite (U-Th)/He cooling ages as well as the modeled age of FB formations to published sedimentary sections. Results indicate that northern Bolivian FTB deformation started at 50 Ma and may have begun as early as 55 Ma. Acceptable rates of shortening permit either a constant rate of shortening ( 4-5 mm/yr) or varying shortening rates with faster rates (7-10 mm/yr) at 45-50 Ma and 12-8 Ma, significantly slower rates (2-4 mm/yr) from 35 to 15 Ma and indicate the northern Bolivian Subandes started deforming between 19 and 14 Ma.

  19. Socioeconomic status and chronic child malnutrition: Wealth and maternal education matter more in the Peruvian Andes than nationally.

    Science.gov (United States)

    Urke, Helga B; Bull, Torill; Mittelmark, Maurice B

    2011-10-01

    This study investigated the association of parents' socioeconomic status (SES) with child stunting in the Peruvian Andes and in Peru nationally. It was hypothesized that the relationship of SES to child stunting would be weaker in the Andean compared with the national sample. This is consistent with earlier research indicating that the relationship of SES to health may be weak in poor regions. The data were from the Demographic and Health Survey 2004 to 2006. Two samples of children 3 to 60 months old were compared: a national sample (n = 1426) and an Andean sample (n = 543). Malnutrition was measured using the indicator "stunting," which is small stature for age. Socioeconomic status was measured using parental education, occupation, and household wealth index (WI). In both samples, SES was significantly related to stunting. The odds of stunting in the poorest WI quintile were significantly higher than in the richest quintile. The same pattern was observed in children of mothers having incomplete primary education compared with children of mothers having complete secondary or higher education. The odds of stunting were significantly lower in children of mothers working at home compared with mothers in professional occupations. The associations of WI and maternal education with stunting were significantly stronger in the Andean compared with the national sample; the study did not find support for the hypothesis. Even in very poor regions such as the Andes, SES may be associated with child health, suggesting the importance of public health measures to overcome the health disadvantages experienced by children living in low SES households. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Ebola (Ebola Virus Disease)

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    ... Controls Cancel Submit Search the CDC Ebola (Ebola Virus Disease) Note: Javascript is disabled or is not ... gov . Recommend on Facebook Tweet Share Compartir Ebola Virus Disease (EVD) is a rare and deadly disease ...

  1. Hepatitis virus panel

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003558.htm Hepatitis virus panel To use the sharing features on this page, please enable JavaScript. The hepatitis virus panel is a series of blood tests used ...

  2. Viruses and Breast Cancer

    Science.gov (United States)

    Lawson, James S.; Heng, Benjamin

    2010-01-01

    Viruses are the accepted cause of many important cancers including cancers of the cervix and anogenital area, the liver, some lymphomas, head and neck cancers and indirectly human immunodeficiency virus associated cancers. For over 50 years, there have been serious attempts to identify viruses which may have a role in breast cancer. Despite these efforts, the establishment of conclusive evidence for such a role has been elusive. However, the development of extremely sophisticated new experimental techniques has allowed the recent development of evidence that human papilloma virus, Epstein-Barr virus, mouse mammary tumor virus and bovine leukemia virus may each have a role in the causation of human breast cancers. This is potentially good news as effective vaccines are already available to prevent infections from carcinogenic strains of human papilloma virus, which causes cancer of the uterine cervix. PMID:24281093

  3. Zika virus disease

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    ... May 2015, the virus was discovered for the first time in Brazil. It has now spread to many territories, states, and countries in: Caribbean Islands Central America Mexico South America Pacific Islands Africa The virus ...

  4. Respiratory Syncytial Virus

    Science.gov (United States)

    ... with facebook share with twitter share with linkedin Respiratory Syncytial Virus (RSV) Credit: CDC This is the ... the United States. Why Is the Study of Respiratory Syncytial Virus (RSV) a Priority for NIAID? In ...

  5. Respiratory syncytial virus (RSV)

    Science.gov (United States)

    RSV; Palivizumab; Respiratory syncytial virus immune globulin; Bronchiolitis - RSV ... Crowe JE. Respiratory syncytial virus. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ...

  6. Viruses and Breast Cancer

    International Nuclear Information System (INIS)

    Lawson, James S.; Heng, Benjamin

    2010-01-01

    Viruses are the accepted cause of many important cancers including cancers of the cervix and anogenital area, the liver, some lymphomas, head and neck cancers and indirectly human immunodeficiency virus associated cancers. For over 50 years, there have been serious attempts to identify viruses which may have a role in breast cancer. Despite these efforts, the establishment of conclusive evidence for such a role has been elusive. However, the development of extremely sophisticated new experimental techniques has allowed the recent development of evidence that human papilloma virus, Epstein-Barr virus, mouse mammary tumor virus and bovine leukemia virus may each have a role in the causation of human breast cancers. This is potentially good news as effective vaccines are already available to prevent infections from carcinogenic strains of human papilloma virus, which causes cancer of the uterine cervix

  7. Viruses and Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, James S., E-mail: james.lawson@unsw.edu.au; Heng, Benjamin [School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney (Australia)

    2010-04-30

    Viruses are the accepted cause of many important cancers including cancers of the cervix and anogenital area, the liver, some lymphomas, head and neck cancers and indirectly human immunodeficiency virus associated cancers. For over 50 years, there have been serious attempts to identify viruses which may have a role in breast cancer. Despite these efforts, the establishment of conclusive evidence for such a role has been elusive. However, the development of extremely sophisticated new experimental techniques has allowed the recent development of evidence that human papilloma virus, Epstein-Barr virus, mouse mammary tumor virus and bovine leukemia virus may each have a role in the causation of human breast cancers. This is potentially good news as effective vaccines are already available to prevent infections from carcinogenic strains of human papilloma virus, which causes cancer of the uterine cervix.

  8. Zika Virus - Multiple Languages

    Science.gov (United States)

    ... Are Here: Home → Multiple Languages → All Health Topics → Zika Virus URL of this page: https://medlineplus.gov/languages/ ... V W XYZ List of All Topics All Zika Virus - Multiple Languages To use the sharing features on ...

  9. VIRUS FAMILIES – contd

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. VIRUS FAMILIES – contd. Minus strand RNA viruses. Rhabdovirus e.g. rabies. Paramyxovirus e.g. measles, mumps. Orthomyxovirus e.g. influenza. Retroviruses. RSV, HTLV, MMTV, HIV. Notes:

  10. Human Parainfluenza Viruses

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search The CDC Human Parainfluenza Viruses (HPIVs) Note: Javascript is disabled or ... CDC.gov . Recommend on Facebook Tweet Share Compartir Human parainfluenza viruses (HPIVs) commonly cause respiratory illnesses in ...

  11. Zika Virus and Pregnancy

    Medline Plus

    Full Text Available ... Guidance & Publications Practice Management Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and Pregnancy Page Navigation ▼ ACOG Pregnancy ...

  12. Zika Virus and Pregnancy

    Medline Plus

    Full Text Available ... My ACOG ACOG Departments Donate Shop Career Connection Home Clinical Guidance & Publications Practice Management Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and Pregnancy Page Navigation ▼ ...

  13. [Mumps vaccine virus transmission].

    Science.gov (United States)

    Otrashevskaia, E V; Kulak, M V; Otrashevskaia, A V; Karpov, I A; Fisenko, E G; Ignat'ev, G M

    2013-01-01

    In this work we report the mumps vaccine virus shedding based on the laboratory confirmed cases of the mumps virus (MuV) infection. The likely epidemiological sources of the transmitted mumps virus were children who were recently vaccinated with the mumps vaccine containing Leningrad-Zagreb or Leningrad-3 MuV. The etiology of the described cases of the horizontal transmission of both mumps vaccine viruses was confirmed by PCR with the sequential restriction analysis.

  14. Nairobi sheep disease virus/Ganjam virus.

    Science.gov (United States)

    M D, Baron; B, Holzer

    2015-08-01

    Nairobi sheep disease virus (NSDV) is a tick-borne virus which causes a severe disease in sheep and goats, and has been responsible for several outbreaks of disease in East Africa. The virus is also found in the Indian subcontinent, where it is known as Ganjam virus. The virus only spreads through the feeding of competent infected ticks, and is therefore limited in its geographic distribution by the distribution of those ticks, Rhipicephalus appendiculata in Africa and Haemaphysalis intermedia in India. Animals bred in endemic areas do not normally develop disease, and the impact is therefore primarily on animals being moved for trade or breeding purposes. The disease caused by NSDV has similarities to several other ruminant diseases, and laboratory diagnosis is necessary for confirmation. There are published methods for diagnosis based on polymerase chain reaction, for virus growth in cell culture and for other simple diagnostic tests, though none has been commercialised. There is no established vaccine against NSDV, although cell-culture attenuated strains have been developed which show promise and could be put into field trials if it were deemed necessary. The virus is closely related to Crimean-Congo haemorrhagic fever virus, and studies on NSDV may therefore be useful in understanding this important human pathogen.

  15. What's West Nile Virus?

    Science.gov (United States)

    ... for Educators Search English Español What's West Nile Virus? KidsHealth / For Kids / What's West Nile Virus? Print en español ¿Qué es el Virus del Nilo Occidental? What exactly is the West ...

  16. Characteristic of pandemic virus

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Characteristic of pandemic virus. The virus was highly transmissible. Risk of hospitalization was 2X and risk of death was about 11X more in comparison to seasonal influenza. Virus continues to be susceptible to Osaltamivir, the only drug available. Vaccines are available but ...

  17. Zika Virus Fact Sheet

    Science.gov (United States)

    ... is caused by a virus transmitted primarily by Aedes mosquitoes. People with Zika virus disease can have symptoms including mild fever, skin ... framework. Q&A: Zika virus and complication ... mosquito from the Aedes genus, mainly Aedes aegypti in tropical regions. Aedes ...

  18. Pathogenic seedborne viruses are rare but Phaseolus vulgaris endornaviruses are common in bean varieties grown in Nicaragua and Tanzania.

    Directory of Open Access Journals (Sweden)

    Noora Nordenstedt

    Full Text Available Common bean (Phaseolus vulgaris is an annual grain legume that was domesticated in Mesoamerica (Central America and the Andes. It is currently grown widely also on other continents including Africa. We surveyed seedborne viruses in new common bean varieties introduced to Nicaragua (Central America and in landraces and improved varieties grown in Tanzania (eastern Africa. Bean seeds, harvested from Nicaragua and Tanzania, were grown in insect-controlled greenhouse or screenhouse, respectively, to obtain leaf material for virus testing. Equal amounts of total RNA from different samples were pooled (30-36 samples per pool, and small RNAs were deep-sequenced (Illumina. Assembly of the reads (21-24 nt to contiguous sequences and searches for homologous viral sequences in databases revealed Phaseolus vulgaris endornavirus 1 (PvEV-1 and PvEV-2 in the bean varieties in Nicaragua and Tanzania. These viruses are not known to cause symptoms in common bean and are considered non-pathogenic. The small-RNA reads from each pool of samples were mapped to the previously characterized complete PvEV-1 and PvEV-2 sequences (genome lengths ca. 14 kb and 15 kb, respectively. Coverage of the viral genomes was 87.9-99.9%, depending on the pool. Coverage per nucleotide ranged from 5 to 471, confirming virus identification. PvEV-1 and PvEV-2 are known to occur in Phaseolus spp. in Central America, but there is little previous information about their occurrence in Nicaragua, and no information about occurrence in Africa. Aside from Cowpea mild mosaic virus detected in bean plants grown from been seeds harvested from one region in Tanzania, no other pathogenic seedborne viruses were detected. The low incidence of infections caused by pathogenic viruses transmitted via bean seeds may be attributable to new, virus-resistant CB varieties released by breeding programs in Nicaragua and Tanzania.

  19. Blueberry (Vaccinium corymbosum)-Virus Diseases

    Science.gov (United States)

    At least six viruses have been found in highbush blueberry plantings in the Pacific Northwest: Blueberry mosaic virus, Blueberry red ringspot virus, Blueberry scorch virus, Blueberry shock virus, Tobacco ringspot virus, and Tomato ringspot virus. Six other virus and virus-like diseases of highbush b...

  20. Late holocene ice core records of climate and environment from the Tropical Andes, Peru

    Directory of Open Access Journals (Sweden)

    1995-01-01

    Full Text Available DONNÉES CLIMATIQUES ET ENVIRONNEMENTALES DÉDUITES DES CAROTTES DE GLACE DES ANDES TROPICALES (PÉROU À L’HOLOCÈNE RÉCENT. On compare l’histoire du climat et de l’environnement reconstituée à partir des carottes extraites de la calotte de glace de Quelccaya (13º56’S, 70º50’O, 5 670 m et de la “Garganta” du Huascarán (9°06’S, 77°36’O, 6 048 m s.n.m. Les paramètres analysés sont le rapport isotopique de l’oxygène ( 18O considéré comme un indicateur des températures, les poussières non solubles et (pour le Huascarán seulement la concentration en nitrates (NO3-, qui est un indicateur des fluctuations de la végétation dans la forêt amazonienne. Les profils du  18O et du NO3- au Huascarán pour les derniers 3 000 ans montrent qu’il y a eu une baisse générale des températures accompagnée par une diminution de l’activité biologique dans le bassin amazonien, avec des valeurs minimales atteintes pendant le Petit Age de Glace, de 200 à 500 ans BP. Il y a eu après une augmentation rapide du  18O, qui a atteint les valeurs d’il y a 3 000 ans BP. Ce réchauffement rapide a dominé les deux derniers siècles sur les deux sites. Les niveaux de NO3- au Huascarán ont aussi augmenté pendant cette période, bien que moins rapidement. L’évidence d’un léger enrichissement isotopique (réchauffement existe entre 1 150 y 900 ans BP, qui pourrait être mis en relation avec “l’Optimum Médiéval”. Le niveau des poussières, constant depuis 3 000 ans, a été interrompu par un événement de fortes concentrations de poussières entre 2 000 y 1 800 ans BP (0-200 A.D. centré sur les années 1 900 BP (100 A.D.. Des pics de moindre importance sont observés de 1 400 à 1 600 ans BP (400 a 600 A.D. et entre 1300 et 1030 BP (entre 700 et 960 A.D.. L’analyse des poussières associées à cet épisode révèle un matériau déposé par les vents de même composition que celui qui affleure en Cordill

  1. Ecología y ocupación del espacio en los Andes Tropicales durante los últimos veinte milenios

    Directory of Open Access Journals (Sweden)

    1973-01-01

    Full Text Available Les Andes tropicales sont constituées par un ensemble de facettes écologiques dont le nombre est fonction du volume montagneux, du régime thermique a la base, de la diversité des modelés, du stock floristique, des effets de façade et d'abri, des modalités d'utilisation de l'espace. L'utilisation de ces facettes par les sociétés d'abord non agricoles, ensuite agricoles, a été très différente. Dans cette zone climatique les changements du climat au cours du Quaternaire ont moins affecté le milieu qu'aux latitudes moyennes, a l'exception des cotes touchées par les variations eustatiques. Aussi, une remarque importante est la constance de l'habitat au cours des 20 derniers millénaires, variant cependant en fonction des diverses facettes écologiques dont le comportement était différent suivant les modifications climatiques. Les glaciations dans les Andes sont relativement synchrones de celles des montagnes des latitudes moyennes, au moins pour le Quaternaire récent elles seraient dues a une meilleure distribution des précipitations au cours de l'année, a une nébulosité plus constante et a un abaissement des températures compris entre 5 et 9º. Les avancées glaciaires entre 20.000 et 16.000 et 14.000 et 10.000 ans BP ont eu des conséquences diverses suivant les milieux humides ou secs et les effets de dominance (en général glace au dessus de 4.000 m mais, jusque vers 2.900 m en Colombie et seulement 4.800 m dans les Andes sèches. Des processus périglaciaires se développent sur 1.000-1.500 m en contrebas dans les Andes sèches alors qu'ils n'affectent qu'une marge très étroite dans les Andes humides (500 m. L'englacement n'a jamais constitué une coupure dans la circulation N-S dans les Andes. Si la haute montagne entre 5 et 10º S était difficilement franchissable, les vallées et bassins intra andins situés entre 1.500 et 3.400 m étaient tièdes, avec une humidité mieux répartie durant l'année, moins secs qu

  2. Viruses of asparagus.

    Science.gov (United States)

    Tomassoli, Laura; Tiberini, Antonio; Vetten, Heinrich-Josef

    2012-01-01

    The current knowledge on viruses infecting asparagus (Asparagus officinalis) is reviewed. Over half a century, nine virus species belonging to the genera Ilarvirus, Cucumovirus, Nepovirus, Tobamovirus, Potexvirus, and Potyvirus have been found in this crop. The potyvirus Asparagus virus 1 (AV1) and the ilarvirus Asparagus virus 2 (AV2) are widespread and negatively affect the economic life of asparagus crops reducing yield and increasing the susceptibility to biotic and abiotic stress. The main properties and epidemiology of AV1 and AV2 as well as diagnostic techniques for their detection and identification are described. Minor viruses and control are briefly outlined. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Understanding Ebola Virus Transmission

    Directory of Open Access Journals (Sweden)

    Seth Judson

    2015-02-01

    Full Text Available An unprecedented number of Ebola virus infections among healthcare workers and patients have raised questions about our understanding of Ebola virus transmission. Here, we explore different routes of Ebola virus transmission between people, summarizing the known epidemiological and experimental data. From this data, we expose important gaps in Ebola virus research pertinent to outbreak situations. We further propose experiments and methods of data collection that will enable scientists to fill these voids in our knowledge about the transmission of Ebola virus.

  4. Protoplasts and plant viruses

    International Nuclear Information System (INIS)

    Murakishi, H.; Lesney, M.S.; Carlson, P.

    1984-01-01

    The use of protoplasts in the study of plant viruses has attracted considerable attention since its inception in the late 1960s. This article is an attempt to assess the current status of protoplasts (primarily) and all cell cultures (in some instances) in studies of virus infection, virus replication, cytopathology, cross-protection, virus resistance, and the use of in vitro methods and genetic engineering to recover virus-resistant plants. These areas of study proved difficult to do entirely with whole plants or plant parts. However, because protoplasts could be synchronously infected with virus, they provided a valuable alternative means of following biochemical and cytological events in relation to the virus growth cycle in a more precise manner than previously possible

  5. First web-based database on total phenolics and oxygen radical absorbance capacity (ORAC) of fruits produced and consumed within the south Andes region of South America.

    Science.gov (United States)

    Speisky, Hernan; López-Alarcón, Camilo; Gómez, Maritza; Fuentes, Jocelyn; Sandoval-Acuña, Cristian

    2012-09-12

    This paper reports the first database on antioxidants contained in fruits produced and consumed within the south Andes region of South America. The database ( www.portalantioxidantes.com ) contains over 500 total phenolics (TP) and ORAC values for more than 120 species/varieties of fruits. All analyses were conducted by a single ISO/IEC 17025-certified laboratory. The characterization comprised native berries such as maqui ( Aristotelia chilensis ), murtilla ( Ugni molinae ), and calafate ( Barberis microphylla ), which largely outscored all other studied fruits. Major differences in TP and ORAC were observed as a function of the fruit variety in berries, avocado, cherries, and apples. In fruits such as pears, apples, apricots, and peaches, a significant part of the TP and ORAC was accounted for by the antioxidants present in the peel. These data should be useful to estimate the fruit-based intake of TP and, through the ORAC data, their antioxidant-related contribution to the diet of south Andes populations.

  6. The Neogene rise of the tropical Andes facilitated diversification of wax palms (Ceroxylon: Arecaceae) through geographical colonization and climatic niche separation

    DEFF Research Database (Denmark)

    Sanín, María José; Kissling, W. Daniel; Bacon, Christine D.

    2016-01-01

    The tropical Andes are a biodiversity hotspot, partly due to their rich and complex floristic composition. A fundamental question regarding this outstanding biodiversity is what role the Andean orogeny has played in species diversification. Ceroxylon is a genus of endemic Andean palms that stands...... gradients. Ancestral areas were reconstructed under a model allowing for founder-event speciation and climatic niches were inferred from climatic variables at present-day occurrences of all species. Niche evolution in a phylogenetic framework was evaluated by testing differences between the climatic niches...... of clades. Our analyses identified four main clades, with a general pattern of diversification through geographical colonization from south to north after the Pliocene uplift of the northern Andes. Adaptation to low temperatures was conserved at the generic level, with climatic niche differentiation among...

  7. EL ROL DEL ANTICICLÓN PACÍFICO EN LA CAÍDA DE NIEVE EN LOS ANDES ÁRIDOS

    Directory of Open Access Journals (Sweden)

    Arnobio G. Poblete

    2016-12-01

    Full Text Available This article aims to study in depth the role the anticyclone subtropical eastern South Pacific (ASPSO on the nival precipitation in the arid Andes, its seasonal variability, fluctuations in the long and medium scale and associations with snowfall. For this reason, the incidence on the ratio of precipitation, the SST in the South Pacific Ocean, precipitable water, wind zonal, Radiation in Outgoing Long Wave and Omega were analyzed. The methodology consisted in the evaluation of the ASPSO through the definition of an index, based on Santiago de Chile (PSGO measured surface atmospheric pressure. This would allow its surveillance and the processing of its temporal behavior in the statistical analysis. The results showed significant time - space associations within the involved variables, which confirmed in all cases the negative impact of ASPSO related to snowfall in the Andes mountains. period 1909-2015.

  8. Ordenar para controlar. Ordenamiento espacial y control político en las Llanuras del Caribe y en los Andes Centrales Neogranadinos. siglo XVIII

    Directory of Open Access Journals (Sweden)

    Beatriz Patiño Millán

    2002-01-01

    Full Text Available Marta Herrera Ángel. Ordenar para Controlar. Ordenamiento espacial y control político en las Llanuras del Caribe y en los Andes Centrales Neogranadinos. Siglo XVIII. Bogotá: Instituto Colombiano de Antropología e Historia - Academia Colombiana de Historia, 2002, pp. 343. En este libro Marta Herrera estudia la estructuración del ordenamiento espacial y político durante el siglo XVIII de las llanuras del Caribe, nombre con el cual denomina el ámbito espacial correspondiente a las gobernaciones de Cartagena y Santa Marta,  y los Andes Centrales, apelativo que utiliza para referirse a los territorios de la provincia de Santafé y la jurisdicción de la ciudad de Tunja.

  9. Seismic studies in the southern Puna plateau and the Peruvian Andes

    Science.gov (United States)

    Calixto Mory, Frank Jimmy

    I present three studies in two regions, both within the Central Andes. In both regions it is clear that there are significant variations in the subduction geometry. I have used surface wave tomography to investigate the shear wave velocity structure beneath the southern Puna plateau and found evidence of widespread melting of the crust beneath the high elevations which correlates with a gap in intermediate depth seismicity and the recent eruptions of ignimbrite complexes. All of these observations can be explained by the delamination of the lithospheric mantle beneath it. I measured Rayleigh wave phase velocities as a function of frequency and inverted then to obtain shear wave velocities as a function of depth. The results show a high velocity body sitting above the subducting Nazca plate beneath the northern edge of the Cerro Galan ignimbrite. This high velocity body is interpreted to be the delaminated piece of lithosphere that detached and sank leading to a localized upwelling of asthenosphere that, in turn, caused widespread crustal melting leading to the eruption of the most recent ignimbrite complexes. Furthermore it is possible that this upwelling also thermally eroded the slab in this region. It is apparent that there is a significant slab gap or hole where there are very few intermediate depth earthquakes. In addition, I have used shear wave splitting analysis and shear wave splitting tomography in the southern Puna plateau to investigate the patterns of seismic anisotropy and mantle flow. The results show very complex shear wave splitting and seismic anisotropy patterns throughout the southern Puna plateau. The observations suggest that different mechanisms are driving the mantle flow from region to region. The subslab mantle outside the region where delamination took place is mostly driven by slab roll back and small degree of coupling between the subducting slab and the mantle below it. In the region apparently dominated by delamination, the subslab

  10. Distribución y conservación de especies amenazadas en Mesoamérica, Chocó y Andes tropicales Distribution and conservation of endangered species in Mesoamerica, Chocó and Tropical Andes

    Directory of Open Access Journals (Sweden)

    María Cecilia Londoño-Murcia

    2011-09-01

    Full Text Available En este estudio se modeló el nicho ecológico proyectado como distribución potencial de 313 especies amenazadas en Mesoamérica, Chocó y los Andes tropicales, según las listas de la UICN. De estas especies, 285 fueron plantas y 28 fueron vertebrados terrestres. La superposición de las distribuciones de las especies amenazadas cubrió prácticamente toda la región. Ecuador mostró cerca del 30% de su área con 50 especies. Colombia, Costa Rica, Guatemala, Nicaragua y Panamá mostraron > 50, aunque en 50% de su área. El Salvador y Honduras, de 11 a 20 en > 50% de su área y México de 1 a 5 especies en > 50% de su área. La distribución de estas especies en áreas transformadas (agricultura y áreas urbanas varió del 11al 30%; El Salvador, Panamá y Guatemala mostraron > 50% de la distribución; Colombia, Honduras y México This study modeled ecological niches projected as potential distributions for 313 endangered species listed in the IUCN for Mesoamerica, Chocó and Tropical Andes, of which 285 were plants, and 28 terrestrial vertebrates. Overlapping of endangered species distributions covered most of the region. Ecuador showed close to 30% of its area with 50 endangered species. Colombia, Costa Rica, Guatemala, Nicaragua y Panama showed more than 50 endangered species in 50% of its area with endangered species (21 to 50 species were Costa Rica, Ecuador, Nicaragua and Panama. El Salvador and Honduras showed > 50% of its area with 11 to 20 endangered species; Mexico showed 50% of endangered species in transformed areas; Colombia, Honduras and Mexico showed < 40%, and Belize and Ecuador showed < 25% of endangered species in transformed areas, respectively. El Salvador, Honduras, Panama, Nicaragua and Mexico showed a high proportion of endangered species in transformed areas for the Classes Amphibia, Liliopsida, Polipodiopsida, and the Orders Asterales, Fabales, Laurales, Myrtales, Scrophulariales and Rubiales. Less than 35% of endangered

  11. (Plio-)Pleistocene alluvial-lacustrine basin infill evolution in a strike-slip active zone (Northern Andes, Western-Central Cordilleras, Colombia)

    OpenAIRE

    SUTER, F.; NEUWERTH, R.; GORIN, G.; GUZMÁN, C.

    2009-01-01

    The (Plio)-Pleistocene Zarzal Formation was deposited in the Cauca Depression and Quindío-Risaralda Basin between the Western and Central Cordilleras (Northern Andes). This area is structurally located on the transcurrent Romeral Fault System (RFS). Because of the interaction between the Nazca plate and the Chocó-Panamá block (an active indenter), the RFS strike-slip component changes direction around the study zone (dextral in the south, senestral in the north). Zarzal sediments are the olde...

  12. Non-volant mammals in a protected area on the Central Andes of Colombia: new records for the Caldas department and the Chinchiná River basin

    OpenAIRE

    Ramírez-Mejía, Andrés; Sánchez, Francisco

    2015-01-01

    The Chinchiná River basin is located on the western slope of the Colombian Central Andes. This basin provides ecosystem services such as water provision for >500,000 people, but has suffered considerable ecosystem degradation, and the information on its biodiversity is limited. We inventoried the non-volant mammals in the Caldas' Central Hydroelectric (CHEC) Reserve in the Chinchiná River basin, in the Caldas department. We detected 18 species of mammals, present the first record of Puma ya...

  13. The ethno-politics of water security: contestations of ethnicity and gender in strategies to control water in the Andes of Peru

    OpenAIRE

    Vera-Delgado, J.

    2011-01-01

    This thesis is the result of a multidisciplinary research which tries to explain water injustices and the threats to water rights access and control experienced by indigenous peasants of the Peruvian Andes. It attempts to contribute to the analysis of the interactions between ethnicity and gender, and to understand how these form an intrinsic part of the contemporary ethno-politics of water. It also critically analyses the role of state interventions and international financial aid programme...

  14. Impact of Santiago de Chile urban atmospheric pollution on anthropogenic trace elements enrichment in snow precipitation at Cerro Colorado, Central Andes

    Science.gov (United States)

    Cereceda-Balic, F.; Palomo-Marín, M. R.; Bernalte, E.; Vidal, V.; Christie, J.; Fadic, X.; Guevara, J. L.; Miro, C.; Pinilla Gil, E.

    2012-02-01

    Seasonal snow precipitation in the Andes mountain range is evaluated as an environmental indicator of the composition of atmospheric emissions in Santiago de Chile metropolitan area, by measuring a set of representative trace elements in snow samples by ICP-MS. Three late winter sampling campaigns (2003, 2008 and 2009) were conducted in three sampling areas around Cerro Colorado, a Central Andes mountain range sector NE of Santiago (36 km). Nevados de Chillán, a sector in The Andes located about 500 km south from the metropolitan area, was selected as a reference area. The experimental results at Cerro Colorado and Nevados de Chillán were compared with previously published data of fresh snow from remote and urban background sites. High snow concentrations of a range of anthropogenic marker elements were found at Cerro Colorado, probably derived from Santiago urban aerosol transport and deposition combined with the effect of mining and smelting activities in the area, whereas Nevados de Chillán levels roughly correspond to urban background areas. Enhanced concentrations in surface snow respect to deeper samples are discussed. Significant differences found between the 2003, 2008 and 2009 anthropogenic source markers profiles at Cerro Colorado sampling points were correlated with changes in emission sources at the city. The preliminary results obtained in this study, the first of this kind in the southern hemisphere, show promising use of snow precipitation in the Central Andes as a suitable matrix for receptor model studies aimed at identifying and quantifying pollution sources in Santiago de Chile.

  15. Pucarilla-Cerro Tipillas volcanic complex: the oldest recognized caldera in the southeastern portion of central volcanic zone of Central Andes?

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, Silvina; Petrinovic, Ivan [CONICET -IBIGEO. Museo de Cs. Naturales, Universidad de Salta, Mendoza 2 (4400), Salta (Argentina)], E-mail: guzmansilvina@gmail.com

    2008-10-01

    We recognize the most eastern and oldest collapse caldera structure in the southern portion of the Central Volcanic Zone of the Andes. A description of Middle-Upper Miocene successions related to explosive- effusive events is presented. The location of this centre close to Cerro Galn Caldera attests a recurrence in the volcanism between 12 and 2 Ma in this portion of the Altiplano - Puna Plateau.

  16. Breeding system of Embothrium coccineum (Proteaceae in two populations on different slopes of the Andes Sistema reproductivo de Embothrium coccineum (Proteaceae en dos poblaciones ubicadas en diferentes laderas de los Andes

    Directory of Open Access Journals (Sweden)

    ADRIANA E ROVERE

    2006-06-01

    Full Text Available Plant breeding systems are considered to reflect species' life history characteristics, selection due to biotic or abiotic factors, pollination conditions, or a combination of these. Reproductive systems may vary over ecological gradients. The breeding system of the ornithophilous Embothrium coccineum (Proteaceae from temperate South America was studied by pollination treatments: manual self-pollination, manual cross-pollination, automatic self-pollination, and natural pollination. These treatments were conducted in a coastal western and an Andean eastern population. Embothrium coccineum was found to be self-incompatible and highly dependent on the pollinating agent at both sites. However, pollen limitations were greater in the coastal population, as breeding efficiency was lower. Populations have different floral visitors whose identity differentially affects reproductive efficiency and pollen flow in E. coccineumLos sistemas de compatibilidad reproductiva en las plantas son considerados una manifestación de la historia de vida, de la selección ante factores abióticos ó bióticos, de las condiciones de polinización o una de combinación de esos factores. El sistema reproductivo de una especie puede variar a lo largo de un gradiente ecológico-ambiental. El sistema reproductivo de Embothrium coccineum (Proteaceae, un árbol ornitófilo endémico de los bosques templados de sur de Sudamérica, fue estudiado mediante experimentos de polinización: autopolinización manual, polinización manual cruzada, autopolinización automática y polinización natural en flores descubiertas. Este trabajo se realizó en una población costera al oeste de la cordillera de los Andes y una población andina ubicada al este de la cordillera de los Andes. En ambas poblaciones se encontró que E. coccineum es autoimcompatible y altamente dependiente de los agentes polinizadores en ambos sitios. Sin embargo, la limitación por polen fue mayor en la poblaci

  17. Aplicación de tres índices bióticos en el río San Juan, Andes, Colombia (Application of three biotic indexes in the river San Juan, Andes, Colombia

    Directory of Open Access Journals (Sweden)

    Mailedt Paola Murillo Torrentes

    2016-09-01

    Full Text Available Durante los meses de febrero, mayo, agosto y octubre del año 2014, se evaluó la calidad del agua del río San Juan. Para tal fin se establecieron seis puntos de muestreo donde se recolectaron muestras de agua y macroinvertebrados acuáticos para los análisis fisicoquímicos e hidrobiológicos. Se aplicaron y modificaron los índices bióticos EPT (efemerópteros, plecópteros, tricópteros, BMWP/Col (Biological Monitoring Working Party y ASPT (Average Score per Taxon basados en las comunidades de macroinvertebrados acuáticos capturados. Los resultados de las variables fisicoquímicas y los índices bióticos indican que las estaciones E1 y E2 son las que presentan menor grado de contaminación, en las demás estaciones disminuye considerablemente la calidad del agua debido a las actividades económicas desarrolladas en el sector y a su cercanías con el casco urbano del municipio de Andes. De los tres índices analizados, el ASPT modificado y adaptado al río San Juan es el que mejor se relaciona con las condiciones ambientales del río en tanto las características de los macroinvertebrados acuáticos recolectados y analizados en el trayecto objeto de estudio. (Abstract. During the months of February, May, August and October 2014, the water quality of the San Juan River was assessed. To this aim, six sampling points were established, where water samples and macroinvertebrates for physical-chemical and hydrobiological analysis were collected. Three biotic indexes were applied and one modified: EPT (Ephemeroptera, Plecoptera, Trichoptera, BMWP / Col (Biological Monitoring Working Party and ASPT (Average Score per Taxon based on the captured communities of aquatic macroinvertebrates. The results of the physical-chemical variables and biotic indixes indicate that E1 and E2 stations are those with lower degree of contamination, other stations considerably decreased water quality due to economic activities around, and the short distance with the

  18. Parasite loads and altitudinal distribution of Liolaemus lizards in the central Chilean Andes Cargas parasitarias y distribución de lagartijas Liolaemus en los Andes de Chile central

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    JOHN H. CAROTHERS

    2001-09-01

    Full Text Available This study compared the distributions of ten species of Liolaemus lizards in the central Chilean Andes to the distributions of four types of parasites: malaria-causing Plasmodium, gut nematodes, ticks, and mites. We wanted to see if parasite numbers might be a factor in determining distributional limits of the lizards. We found that there was no evidence of malarial infestation of the lizards, that ticks were almost absent, that more often than not mite numbers decreased at the distributional limits of the lizards, and that gut nematodes confined to the herbivorous lizards in our sample may well be beneficial rather than detrimental. Rather than parasitism, other biotic interactions (e.g., predation or competition are more likely candidates as factors influencing lizard elevational distributions, as are abiotic characteristics such as microhabitat availabilities and thermal factorsEste estudio compara las distribuciones de diez especies de lagartijas Liolaemus en los Andes de Chile central, con las distribuciones de cuatro tipos de parásitos: Plasmodium causantes de malaria, nemátodos intestinales, garrapatas y ácaros. Quisimos verificar si los números de parásitos pudieran ser un factor determinante de los límites de distribución de las lagartijas. Encontramos que no había evidencia de infestación por malaria en las lagartijas; que las garrapatas estaban casi ausentes; que los números de ácaros más a menudo decrecían que aumentaban en los límites distribucionales de las lagartijas; y que los nemátodos intestinales confinados a las lagartijas herbívoras en nuestra muestra bien podían ser beneficiosos antes que dañinos. Más bien que parasitismo, otras interacciones bióticas (e.g., depredación o competencia son candidatos más probables como factores que influyen las distribuciones altitudinales de las lagartijas, además de características abióticas tales como la disponibilidad de microhábitats y los factores térmicos

  19. Religión, género y construcción de una sexualidad en los Andes (Siglos XVI y XVII. Una acercamiento provisional

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    Armas Asin, Fernando

    2001-12-01

    Full Text Available This study emphasizes the conceptual changes in regard to sex, sexuality and general genre relations in the Andes, in the 16th and 17th centuries, in the context of the establishment of the colonial society. It is analyzed the way in which a new discourse on the body was developed as a consequence of the deeply represive baroque culture. This culture recreated religious values which controlled every aspect of the daily life. It also enforced a rigid legislation which ruled through society as a whole.

    El estudio busca enfatizar los cambios conceptuales que se produjeron en torno al sexo, la sexualidad, y, en términos generales, en las relaciones de género en los Andes en los siglos XVI y XVII, en un contexto de establecimiento de la sociedad colonial. Se analiza cómo se construyó un nuevo discurso sobre el cuerpo en los Andes como consecuencia de la cultura barroca, profundamente represiva. Dicha cultura recreó valores religiosos que controlaban todos los aspectos de la vida diaria, además de poner en marcha una legislación muy rígida que reguló toda la sociedad.

  20. Diagnostic of annual cycle and effects of the ENSO about the maximum intensity of duration rains between 1 and 24 hours at the Andes of Colombia

    International Nuclear Information System (INIS)

    Poveda, German; Mesa, Oscar; Toro, Vladimir; Agudelo, Paula; Alvarez, Juan F; Arias, Paola; Moreno, Hernan; Salazar, Luis; Vieira, Sara

    2002-01-01

    We study the distribution of maximum rainfall events during the annual cycle, for storms ranging from 1 to 24-hour in duration; by using information over 51 rain gauges locate at the Colombian Andes. Also, the effects of both phases of ENSO (El Nino and La Nina) are quantified. We found that maximum rainfall intensity events occur during the rainy periods of march-may and September-November. There is a strong similarity between the annual cycle of mean total rainfall and that of the maximum intensities of rainfall over the tropical Andes. This result is quite consistent throughout the three ranges of the Colombian Andes. At inter annual timescales, we found that both phases of ENSO are associated with disturbances of maximum rainfall events; since during La Nina there are more intense precipitation events than during El Nino, overall, for durations longer than 3 hours, rainfall intensity gets reduced by one order of magnitude with respect to shorter durations (1-3 hours). The most extreme recorded rainfall events are apparently not associated with the annual and inter annual large scales forcing and appear to be randomly generated by the important role of the land surface atmosphere in the genesis and dynamics of intense storm over central Colombia

  1. Uplift sequence of the Andes at 30°S: Insights from sedimentology and U/Pb dating of synorogenic deposits

    Science.gov (United States)

    Suriano, J.; Mardonez, D.; Mahoney, J. B.; Mescua, J. F.; Giambiagi, L. B.; Kimbrough, D.; Lossada, A.

    2017-04-01

    The South Central Andes at 30°S represent a key area to understand the Andes geodynamics as it is in the middle of the flat slab segment and all the morphotectonic units of the Central Andes are well developed. This work is focused in the proximal synorogenic deposits of the Western Precordillera, in the La Tranca valley, in order to unravel the uplift sequence of this belt. Nine facies associations were recognized; most of them represent piedmont facies with local provenance from Precordillera and were deposited in the wedge-top depozone, as is expected for proximal sinorogenic deposits. However there are intercalations of transference fluvial systems, which show mixed provenance indicating that Permo-Triassic igneous rocks were already exposed to the west (Frontal Cordillera). There are also lacustrine deposits which are interpreted as the result of damming by fault activity at east of the studied basin. Finally, two maximum depositional ages at ca. 11 Ma and 8 Ma of these deposits indicate that the onset of uplift of the Precordillera at 30°S is little older than 11 Ma. These data change two previous ideas about the evolution of the Precordillera: its uplift at 30° S is younger than proposed by previous works and it is nearly synchronous along strike.

  2. [The great virus comeback].

    Science.gov (United States)

    Forterre, Patrick

    2013-01-01

    Viruses have been considered for a long time as by-products of biological evolution. This view is changing now as a result of several recent discoveries. Viral ecologists have shown that viral particles are the most abundant biological entities on our planet, whereas metagenomic analyses have revealed an unexpected abundance and diversity of viral genes in the biosphere. Comparative genomics have highlighted the uniqueness of viral sequences, in contradiction with the traditional view of viruses as pickpockets of cellular genes. On the contrary, cellular genomes, especially eukaryotic ones, turned out to be full of genes derived from viruses or related elements (plasmids, transposons, retroelements and so on). The discovery of unusual viruses infecting archaea has shown that the viral world is much more diverse than previously thought, ruining the traditional dichotomy between bacteriophages and viruses. Finally, the discovery of giant viruses has blurred the traditional image of viruses as small entities. Furthermore, essential clues on virus history have been obtained in the last ten years. In particular, structural analyses of capsid proteins have uncovered deeply rooted homologies between viruses infecting different cellular domains, suggesting that viruses originated before the last universal common ancestor (LUCA). These studies have shown that several lineages of viruses originated independently, i.e., viruses are polyphyletic. From the time of LUCA, viruses have coevolved with their hosts, and viral lineages can be viewed as lianas wrapping around the trunk, branches and leaves of the tree of life. Although viruses are very diverse, with genomes encoding from one to more than one thousand proteins, they can all be simply defined as organisms producing virions. Virions themselves can be defined as infectious particles made of at least one protein associated with the viral nucleic acid, endowed with the capability to protect the viral genome and ensure its

  3. A glassy lava flow from Toconce volcano and its relation with the Altiplano-Puna Magma Body in Central Andes

    Science.gov (United States)

    Godoy, B.; Rodriguez, I.; Aguilera, F.

    2012-12-01

    Toconce is a composite stratovolcano located at the San Pedro - Linzor volcanic chain (SPLVC). This volcanic chain distributes within the Altiplano-Puna region (Central Andes) which is characterized by extensive rhyodacitic-to-rhyolitic ignimbritic fields, and voluminous domes of dacitic-to-rhyolitic composition (de Silva, 1989). The felsic melts that gave origin to ignimbrites and domes at this area were generated by mixing of mantle-derived magmas and anatectic melts assimilated during their ascent through the thick crust. Thus, partially molten layers exist in the upper crust below the APVC (de Silva et al., 2006). Evidence of large volumes of such melts has been also proposed by geophysical methods (i.e. the Altiplano-Puna Magma Body; Chmielowsky et al., 1999) In this work, petrography and whole rock, mineralogical and melt inclusions geochemistry of a glassy lava flow of Toconce volcano are presented. Petrographically, this lava flow shows a porphyric texture, with euhdral to subhedral plagioclase, ortho- and clino-pyroxene phenocrysts immersed in a glassy groundmass. Geochemically, the lava flow has 64.7% wt. SiO2. The glassy groundmass (~70% wt. SiO2) is more felsic than all the lavas in the volcanic chain (47-68% wt., Godoy et al., 2011). Analyzed orthopyroxene-hosted melt inclusions show an even higher SiO2 content (72-75% wt.), and a decreasing on Al2O3, Na2O, and CaO content with differentiation. Crystallization pressures of this lava flow, obtained using Putirka's two-pyroxene and clinopyroxene-liquid models (Putirka, 2008), range between 6 and 9 kbar. According to crystallization pressures, and major element composition, a felsic source located at shallow crustal pressures - where plagioclase is a stable mineralogical phase - originated the inclusions. This could be related to the presence of the Altiplano-Puna Magma Body (APMB) located below SPLVC. On the other hand, glassy groundmass, and disequilibrium textures in minerals of this lava flow could

  4. Postmortem stability of Ebola virus.

    Science.gov (United States)

    Prescott, Joseph; Bushmaker, Trenton; Fischer, Robert; Miazgowicz, Kerri; Judson, Seth; Munster, Vincent J

    2015-05-01

    The ongoing Ebola virus outbreak in West Africa has highlighted questions regarding stability of the virus and detection of RNA from corpses. We used Ebola virus-infected macaques to model humans who died of Ebola virus disease. Viable virus was isolated <7 days posteuthanasia; viral RNA was detectable for 10 weeks.

  5. The 2012-2014 eruptive cycle of Copahue Volcano, Southern Andes. Magmatic-Hydrothermal system interaction and manifestations.

    Science.gov (United States)

    Morales, Sergio; Alarcón, Alex; Basualto, Daniel; Bengoa, Cintia; Bertín, Daniel; Cardona, Carlos; Córdova, Maria; Franco, Luis; Gil, Fernando; Hernandez, Erasmo; Lara, Luis; Lazo, Jonathan; Mardones, Cristian; Medina, Roxana; Peña, Paola; Quijada, Jonathan; San Martín, Juan; Valderrama, Oscar

    2015-04-01

    Copahue Volcano (COPV), in Southern Andes of Chile, is an andesitic-basaltic stratovolcano, which is located on the western margin of Caviahue Caldera. The COPV have a NE-trending fissure with 9 aligned vents, being El Agrio the main currently active vent, with ca. 400 m in diameter. The COPV is placed into an extensive hydrothermal system which has modulated its recent 2012-2014 eruptive activity, with small phreatic to phreatomagmatic eruptions and isolated weak strombolian episodes and formation of crater lakes inside the main crater. Since 2012, the Southern Andes Volcano Observatory (OVDAS) carried out the real-time monitoring with seismic broadband stations, GPS, infrasound sensors and webcams. In this work, we report pre, sin, and post-eruptive seismic activity of the last two main eruptions (Dec, 2012 and Oct, 2014) both with different seismic precursors and superficial activity, showing the second one a particularly appearance of seismic quiescence episodes preceding explosive activity, as an indicator of interaction between magmatic-hydrothermal systems. The first episode, in late 2012, was characterized by a low frequency (0.3-0.4 Hz and 1.0-1.5 Hz) continuous tremor which increased gradually from background noise level amplitude to values of reduced displacement (DR), close to 50 cm2 at the peak of the eruption, reaching an eruptive column of ~1.5 km height. After few months of recording low energy seismicity, a sequence of low frequency, repetitive and low energy seismic events arose, with a frequency of occurrence up to 300 events/hour. Also, the VLP earthquakes were added to the record probably associated with magma intrusion into a deep magmatic chamber during all stages of eruptive process, joined to the record of VT seismicity during the same period, which is located throughout the Caviahue Caldera area. Both kind of seismic patterns were again recorded in October 2014, being the precursor of the new eruptive cycle at this time as well as the

  6. Changing Precipitation Patterns or Waning Glaciers? Identifying Water Supply Vulnerabilities to Climate Change in the Bolivian Andes

    Science.gov (United States)

    Guido, Z. S.; McIntosh, J. C.; Papuga, S. A.

    2010-12-01

    The Bolivian Andes have become an iconic example for the impacts of climate change. Glaciers are rapidly melting and some have already completely disappeared. More than 75 percent of the water consumed by 2 million people living on the flanks of the Bolivian Andes comes from mountains and it is often cited that the dwindling ice threatens the water supply of the expanding and destitute population living in the twin cities of La Paz and El Alto. However, the wet and the warm seasons and the cold and dry seasons coincide, causing high precipitation and ice melt—and therefore high streamflows—to occur only in the austral summer (October-March); during the austral winter, cold conditions limit glacier melt. This suggests that reductions in the water supply could be influenced more by changing precipitation amounts than continued glacial mass-wasting. We hypothesize that precipitation is the principal component of groundwater recharge for the aquifers at the base of the central Cordillera Real. Oxygen and hydrogen isotopes from rivers partially fed by glaciers, groundwater, and glacial melt water can help determine the relative contribution of precipitation and glacial melt to important water supplies. During the dry season in August 2010, we sampled 23 sites that follow the flow path of water in the Condiriri watershed, beginning in the glacial headwaters and ending several kilometers upriver from Lake Titicaca. We collected five samples at the toe of the Pequeño Alpamayo glacier and four samples from three tributary rivers that drain glaciated headwaters, which include meltwater from the Pequeño Alpamayo glacier. W also collected 14 water samples from shallow and deep wells in rural communities within 40 kilometers of the glaciers. If the isotopic values of groundwater are similar to rain values, as we suspect, precipitation is likely the largest contributor to groundwater resources in the region and will suggest that changing precipitation patterns present the

  7. Assimilating Non-linear Effects of Customized Large-Scale Climate Predictors on Downscaled Precipitation over the Tropical Andes

    Science.gov (United States)

    Molina, J. M.; Zaitchik, B. F.

    2016-12-01

    Recent findings considering high CO2 emission scenarios (RCP8.5) suggest that the tropical Andes may experience a massive warming and a significant precipitation increase (decrease) during the wet (dry) seasons by the end of the 21st century. Variations on rainfall-streamflow relationships and seasonal crop yields significantly affect human development in this region and make local communities highly vulnerable to climate change and variability. We developed an expert-informed empirical statistical downscaling (ESD) algorithm to explore and construct robust global climate predictors to perform skillful RCP8.5 projections of in-situ March-May (MAM) precipitation required for impact modeling and adaptation studies. We applied our framework to a topographically-complex region of the Colombian Andes where a number of previous studies have reported El Niño-Southern Oscillation (ENSO) as the main driver of climate variability. Supervised machine learning algorithms were trained with customized and bias-corrected predictors from NCEP reanalysis, and a cross-validation approach was implemented to assess both predictive skill and model selection. We found weak and not significant teleconnections between precipitation and lagged seasonal surface temperatures over El Niño3.4 domain, which suggests that ENSO fails to explain MAM rainfall variability in the study region. In contrast, series of Sea Level Pressure (SLP) over American Samoa -likely associated with the South Pacific Convergence Zone (SPCZ)- explains more than 65% of the precipitation variance. The best prediction skill was obtained with Selected Generalized Additive Models (SGAM) given their ability to capture linear/nonlinear relationships present in the data. While SPCZ-related series exhibited a positive linear effect in the rainfall response, SLP predictors in the north Atlantic and central equatorial Pacific showed nonlinear effects. A multimodel (MIROC, CanESM2 and CCSM) ensemble of ESD projections revealed

  8. Integrating river incision rates over timescales in the Ecuadorian Andes: from uplift history to current erosion rates

    Science.gov (United States)

    Campforts, Benjamin; Govers, Gerard; Vanacker, Veerle; Tenorio, Gustavo

    2013-04-01

    River profile development is studied at different timescales, from the response to uplift over millions of years over steady state erosion rates over millennia to the response to a single event, such as a major landslide. At present, few attempts have been made to compare data obtained over various timescales. Therefore we do not know to what extent data and model results are compatible: do long-term river profile development models yield erosion rates that are compatible with information obtained over shorter time spans, both in terms of absolute rates and spatial patterns or not? Such comparisons could provide crucial insights into the nature of river development and allow us to assess the confidence we may have when predicting river response at different timescales (e.g. Kirchner et al., 2001). A major issue hampering such comparison is the uncertainty involved in the calibration of long-term river profile development models. Furthermore, calibration data on different timescales are rarely available for a specific region. In this research, we set up a river profile development model similar to the one used by Roberts & White (2010) and successfully calibrated it for the northern Ecuadorian Andes using detailed uplift and sedimentological data. Subsequently we used the calibrated model to simulate river profile development in the southern Ecuadorian Andes. The calibrated model allows to reconstruct the Andean uplift history in southern Ecuador, which is characterized by a very strong uplift phase during the last 5 My. Erosion rates derived from the modeled river incision rates were then compared with 10Be derived basin-wide erosion rates for a series of basins within the study area. We found that the model-inferred erosion rates for the last millennia are broadly compatible with the cosmogenic derived denudation rates, both in terms of absolute erosion rates as well as in terms of their spatial distribution. Hence, a relatively simple river profile development

  9. Holocene compression in the Acequión valley (Andes Precordillera, San Juan province, Argentina): Geomorphic, tectonic, and paleoseismic evidence

    Science.gov (United States)

    Audemard, M.; Franck, A.; Perucca, L.; Laura, P.; Pantano, Ana; Avila, Carlos R.; Onorato, M. Romina; Vargas, Horacio N.; Alvarado, Patricia; Viete, Hewart

    2016-04-01

    The Matagusanos-Maradona-Acequión Valley sits within the Andes Precordillera fold-thrust belt of western Argentina. It is an elongated topographic depression bounded by the roughly N-S trending Precordillera Central and Oriental in the San Juan Province. Moreover, it is not a piggy-back basin as we could have expected between two ranges belonging to a fold-thrust belt, but a very active tectonic corridor coinciding with a thick-skinned triangular zone, squeezed between two different tectonic domains. The two domains converge, where the Precordillera Oriental has been incorporated to the Sierras Pampeanas province, becoming the western leading edge of the west-verging broken foreland Sierras Pampeanas domain. This latter province has been in turn incorporated into the active deformation framework of the Andes back-arc at these latitudes as a result of enhanced coupling between the converging plates due to the subduction of the Juan Fernández ridge that flattens the Nazca slab under the South American continent. This study focuses on the neotectonics of the southern tip of this N-S elongated depression, known as Acequión (from the homonym river that crosses the area), between the Del Agua and Los Pozos rivers. This depression dies out against the transversely oriented Precordillera Sur, which exhibits a similar tectonic style as Precordillera Occidental and Central (east-verging fold-thrust belt). This contribution brings supporting evidence of the ongoing deformation during the Late Pleistocene and Holocene of the triangular zone bounded between the two leading and converging edges of Precordillera Central and Oriental thrust fronts, recorded in a multi-episodic lake sequence of the Acequión and Nikes rivers. The herein gathered evidence comprise Late Pleistocene-Holocene landforms of active thrusting, fault kinematics (micro-tectonic) data and outcrop-scale (meso-tectonic) faulting and folding of recent lake and alluvial sequences. In addition, seismically

  10. Losing fat, gaining treatments: the use of biomedicine as a cure for folk illnesses in the Andes.

    Science.gov (United States)

    Blaisdell, Amy; Vindal Ødegaard, Cecilie

    2014-07-03

    This article explores how people in the Andes incorporate beliefs from both biomedical and ethnomedical systems in treating folk illnesses that often involve spiritual beings. The article focuses on the kharisiri-one who is believed to steal fat and blood from unsuspecting humans to make exchanges with the devil. The kharisiri in turn is rewarded with good fortune. Victims of kharisiris, however, fall ill and may die if untreated. Historically, kharisiri victims relied on ethnomedicine for treatment, but it appears biomedical pills are now perceived by some as an effective treatment. By drawing on participants' attitudes towards biomedicine, and how people in the Andes conceptualize health, this article theorizes as to why biomedical pills are sought to treat kharisiri attacks but not for other folk illnesses. Fieldwork was conducted in Arequipa and Yunguyo among market vendors, who make up a significant portion of Peru's working population. This type of work increases the risk of different illnesses due to work conditions like exposure to extreme temperatures, long-distance travel, and social dynamics. Biomedical and ethnomedical products are often sold in and around marketplaces, making vendors a compelling group for exploring issues relating to treatment systems. Qualitative data was collected in 2011 with a follow-up visit in 2013. Participant observation, informal conversations, and unstructured interviews with 29 participants informed the study. Participants unanimously reported that biomedical pills are not capable of treating folk illnesses such as susto and mal de ojo. Several participants reported that pharmaceutical pills can cure kharisiri victims. In comparison to other folk illnesses that involve spiritual beings, those who fall ill from a kharisiri attack lose physical elements (fat and blood) rather than their soul (ánimo) or becoming ill due to a misbalance in reciprocal relations-either with humans or non-human beings such as Pachamama. Because

  11. Distribución y densidad de la trucha Oncorhynchus mykiss (Salmoniformes: Salmonidae en los Andes venezolanos

    Directory of Open Access Journals (Sweden)

    Jaime E. Péfaur

    1998-09-01

    Full Text Available En el presente trabajo se informa acerca de la distribución espacial y la abundancia de las poblaciones de la trucha arcoiris silvestre en los Andes Venezolanos, con base en recolectas en 68 estaciones de muestreo durante un año. Ubicadas entre 500 y 4000 msnm en siete cuencas hidrográficas de los ríos más importantes de los Andes de Venezuela. Un total de 612 individuos fueron obtenidos en estaciones por encima de los 1700 m. La mayoría de los peces de recogieron en las cuencas de los ríos Chama (43%, Motatán (21% y Santo Domingo (32%, con sólo algunos ejemplares recolectados en los ríos Negro (1.75% y La Grita (0-33%, y con ausencia de capturas en los ríos Escalante y Mocotíes. Los machos adultos superan numéricamente a las hembras en una posición de 2.15: 1. Los juveniles conforman un 56.7% del total de capturas, con una proporción de 1.30 juveniles por adulto. El tamaño de los especímenes varió desde 2.0 a 21.8 cm. Con casi la mitad de ellos dentro del intervalo 5.1 - 10.0 cm. El peso de los ejemplares también presentó una amplia variación, con un máximo de 317.0g.Spatial distribution and relative abundance of wild rainbow trout populations were studied in 68 stations located between 500 and 4000 masl in seven hydrological basins of the most important Andean rivers of Venezuela during a year of sampling. A total of 612 individuals were obtained above 1700 m. Most fishes were obtained from the Chama ( 43%, Motatán (21% and Santo Domingo (32% rivers, very few in the Negro (1.75% and La Grita (0.33% rivers, and none in the Escalante and Mocotíes rivers basins. Adult males were more abundant than females in a 2.15:1 proportion. Juveniles made a 56.7% of captures, with a proportion of 1.30 juveniles per adult. Individual sizes varied from 2.0 to 21.8 cm, most within the interval 5.1 - 10.0 cm; the weight of specimens also showed an ample variation, with a maximum of 317.0 g.

  12. Hydrological interaction between glacier and páramos in the tropical Andes: implications for water resources availability

    Science.gov (United States)

    Villacís, Marcos; Cadier, Eric; Mena, Sandra; Anaguano, Marcelo; Calispa, Marlon; Maisisncho, Luis; Galárraga, Remigio; Francou, Bernard

    2010-05-01

    Preliminary hydro glacier estimates indicate that glacier contribution to the average annual consumption (5.6 m3 s-1) of the city of Quito (Capital of Ecuador, ~2'500.000 inhabitants, 2800 masl) represents only about 2%-4% of the total supply for human consumption. However, at the local level at the Antizana volcano (0°28'S, 78°09'W), the mass balance analysis of the system composed by the Humboldt catchment (area of 15.1 km2, 15% of glaciarized area, 5% of moraines area, 80% of the area is páramo-endemic ecosystem of the tropical Andes, range from 5670 masl to 4000 masl) and Los Crespos catchment (area of 2.4 km2, 67% glaciarized area, 27% moraines area, range from 5670 masl to 4500 masl), which is nested into the Humboldt catchment, allows us to identify that due to the presence of the glacier reservoirs there is an additional contribution of 24% to the annual volume at the Humboldt catchment and it helps to regulate the runoff during the dry season, where the daily additional glacier contribution from November to February in some cases could reach t 40%. The Humboldt catchment has similar physiographic characteristics than the sites where new diversions will be built in the future in order to satisfy the increasing demand of water for human consumption of the city of Quito and its surrounding populations. Based on detail hydrological observations (every 15 minutes measurements) during 2005 to 2009 and sporadic environmental trace analysis during the same period, the annual percentage of glacier contribution from the Humboldt catchment could potentially be as high as 37% due in part to the glacier melt contribution that gets infiltrated over 4750 masl it is then delivered around 4100 masl through underground circulation. Some of the sites where the glacier contribution reaches de surface has been identified through field work and the glacier origin of this water have been confirmed using a conductivity measurement, which seems to be a good indicator in when

  13. Migraciones en la puna: su relación con el uso de los recursos naturales del departamento Los Andes Migraciones en la puna: su relación con el uso de los recursos naturales del departamento Los Andes

    Directory of Open Access Journals (Sweden)

    Francisco R. Barbarán

    2009-12-01

    Full Text Available From an historic and demographic perspective, as well as the use of natural resources, we analyzed the relationship between human migrations and the economic activities of Los Andes Department, West of the Salta Province, in NW Argentina. Using the residual method, we calculated migratory balances between Argentinean population censuses carried out in 1947,1960, 1970, 1980 and 2001. The migratory balances were negative for all the periods studied. When the train started to run through Ramal C-14, the workers who built it have to find jobs somewhere else. At the same time, the railway made easier for the natives, to find better economicopportunities out of the Puna. The close of mine La Casualidad by the end of the 70’s, the low creation of jobs by the remaining mining operations, focused in to hire qualified technicians no available in Los Andes and the privatization of the railway in early 90’s, were important factors of emigration. Despite of cattle rising as the main economic activity in rural areas, it is practiced without any technology of management. The overgrazing caused for that reason, has reduced almost to the half the quantity of sheep by inhabitant between 1947 and 2001. That is why the local people have to press more on the wildlife, trading illegally with vicuña (Vicugna vicugna fiber. Despite of a touristic development plan, a law promoting sheep rising and a census of vicuña population carried out by the provincial government, these recent actions should be part of a development project of regional scale, oriented to the sustainable use of the natural resources of Los Andes Department. That project would create jobs and discourage emigration.Desde una perspectiva histórica, demográfica y del uso de los recursos naturales, analizamos la relación existente entre las migraciones humanas y las actividades económicas en el departamento Los Andes, ubicado al W de la provincia de Salta, en el Noroeste Argentino. Usando el m

  14. British medicine in the Peruvian Andes: the travels of Archibald Smith M.D. (1820-1870 Medicina britânica nos Andes peruanos: as viagens do médico Archibald Smith (1820-1870

    Directory of Open Access Journals (Sweden)

    Jorge Lossio

    2006-12-01

    Full Text Available This article traces the travels of the Scottish physician Archibald Smith through the Peruvian Andes between the 1820s and 1860s. Despite his prominent role in the nineteenth-century Peruvian medical scene, almost nothing has been written on Archibald Smith. By exploring Smith's medical activities, publications, and debates, this article intends to uncover unexplored areas of Peruvian medical history, such as the animosity between local and foreign physicians during the post-Independence war era and the important role played by medical geography as a scientific discipline for redefining ethnical and regional issues.O presente artigo traça a vida e obra do médico escocês Archibald Smith durante sua permanência no Peru, entre as décadas de 1820 e 1860. Apesar de sua proeminente contribuição para a medicina peruana, quase nada foi escrito sobre Archibald Smith. Através da investigação das atividades, publicações e debates de que Smith participou, o artigo pretende desvendar áreas inexploradas da história da medicina no Peru, tais como a animosidade entre os médicos locais e estrangeiros no pós-guerra de independência e o papel importante da geografia médica como disciplina científica que redefine questões étnicas e regionais.

  15. Diagnóstico virológico y molecular de virus transmitidos por roedores. Hantavirus y arenavirus

    Directory of Open Access Journals (Sweden)

    Silvana Levis

    2010-04-01

    Full Text Available Los hantavirus (familia Bunyaviridae y arenavirus (familia Arenaviridae son virus de roedores; cada uno de ellos parece estar estrictamente asociado con una especie de roedor en la que causa una infección persistente y asintomática. En las Américas tienen como reservorios primarios a roedores de la sub-familia Sigmodontinae, y son causantes de síndrome pulmonar por Hantavirus (SPH y fiebres hemorrágicas, respectivamente (1,2. El número de estos virus identificados en los últimos años ha aumentado significativamente; actualmente, el género Hantavirus está compuesto por más de 28 tipos diferentes, mientras que al menos 23 arenavirus conforman el género Arenavirus. Entre los hantavirus asociados con SPH se destacan el virus Sin Nombre en Norteamérica, y los virus Andes, Laguna Negra, Caño Delgadito, Araraquara y Juquitiba, en el cono sur de América, entre otros (2. Los arenavirus asociados a fiebres hemorrágicas reconocidos en Sud América al presente son: Junín (Argentina, Guanarito (Venezuela, Sabiá (Brasil, y Machupo y Chapare (Bolivia (3.

  16. Zika virus infection.

    Science.gov (United States)

    Pougnet, Laurence; Thill, Chloé; Pougnet, Richard; Auvinet, Henri; Giacardi, Christophe; Drouillard, Isabelle

    2016-12-01

    A 21-year old woman from New-Caledonia had 40 ̊C fever with vomiting, arthralgia, myalgia, and measles-like rash. Etiological analyses showed primary infection with Zika virus. Because of severe clinical presentation, she was hospitalized in the intensive care unit of the Brest military Hospital. Zika virus is mainly transmitted by Aedes mosquitoes. If they settle in Metropolitan France, Zika virus might also spread there.

  17. Contribución del programa 'Nieves y glaciares tropicales' (NGT al conocimiento de la variabilidad climática en los Andes

    Directory of Open Access Journals (Sweden)

    1998-01-01

    Full Text Available CONTRIBUTION DU PROGRAMME “NEIGES ET GLACIERS TROPICAUX” (NGT À LA CONNAISSANCE DE LA VARIABILITÉ CLIMATIQUE DANS LES ANDES. Les glaciers tropicaux sont d’excellents indicateurs de l’évolution du climat à cause de leur extrême sensibilité aux variations des paramètres météorologiques tels que les températures, la radiation, les précipitations etc. (Pouyaud et al., 1995. Ils ont enregistré les implications climatiques des phénomènes El Niño (ENSO et ils peuvent donner des informations précieuses sur leur fréquence et leur amplitude. Ce sont aussi des objets hydrologiques et les populations andines exploitent leurs ressources. Ils peuvent évoluer très rapidement. Le recul actuel, accéléré et généralisé des glaciers des Andes centrales a des conséquences hydrologiques et peut constituer des risques naturels. L’ORSTOM et ses partenaires scientifiques andins ont mis en route depuis 1991 un vaste programme de suivi dans l’ensemble des Andes tropicales. On évalue les résultats de ce programme jusqu’à la fin 1997. Los glaciares tropicales son excelentes indicadores de la evolución del clima por su extrema sensibilidad a las variaciones de los parámetros meteorológicos como las temperaturas, la radiación y las precipitaciones, etc. (Pouyaud et al., 1995. Bajo este concepto, han registrado las implicaciones climáticas de los fenómenos El Niño-Oscilación del Sur (ENSO y pueden proporcionar valiosas informaciones sobre su frecuencia y su magnitud. Son también objetos hidrológicos, cuyos recursos son aprovechados por las sociedades andinas, susceptibles de evoluciones futuras muy rápidas. El actual retroceso, generalizado y acelerado, de los glaciares de los Andes centrales y sus consecuencias en términos de hidrología o de riesgos naturales, condujeron al ORSTOM y sus contrapartes científicas andinas a lanzar desde 1991 un amplio programa de monitoreo de estos glaciares en el conjunto de los Andes tropicales

  18. Resilience and adaptations of rural communities and agricultural land use in the tropical Andes: Coping with environmental and socio-economic changes

    Directory of Open Access Journals (Sweden)

    Stadel, Ch.

    2008-12-01

    Full Text Available In spite of a long settlement history of the tropical Andes, rural farming communities have always been exposed to conditions of ecological and economic vulnerability, risks, and even disasters. This has resulted, at certain times and in some regions, to a destabilization of livelihoods and to a manifestation of various forms of marginalization, to poverty or outmigration. However, Andean communities , over a long time, have given admirable testimonies of resilience and adaptations in the face of adverse conditions or new challenges. This paper examines the potentials and different facets of resilience and adaptation strategies of the rural campesinado in the tropical Andes. It emphasizes the proven traditional concepts of verticality, complementarity, reciprocity, and mutual community support, which to date support the feasibility and sustainability of Andean farming and community survival. In spite of this recognition, it is argued that Andean rural livelihoods always had to adapt to new developments, to threats and challenges, as well as to opportunities and alternative potentials. In the face of an almost ubiquitous penetration of modernization, new technologies, and economic and cultural globalization, the fundamental question arises, whether this can be considered as a path to progress and development, or as a threat to the survival of small-scale farming and rural community living. The paper concludes by formulating, albeit in a tentative form, some general suggestions for ‘development’ approaches and for research priorities in the rural Andes.

    A pesar de una tradición muy extensa del asentamiento humano en los Andes tropicales, las comunidades campesinas siempre enfrentaron condiciones de vulnerabilidad ecológica y económica, con varios riesgos, y aun desastres. Eso ha resultado, en diversos tiempos y en algunas regiones, en una estabilización de la superviviencia humana y en varias manifestaciones de marginalización, de

  19. Ebola (Ebola Virus Disease): Diagnosis

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search the CDC Ebola (Ebola Virus Disease) Note: Javascript is disabled or is ... message, please visit this page: About CDC.gov . Ebola (Ebola Virus Disease) What is Ebola Virus Disease? ...

  20. Ebola (Ebola Virus Disease): Transmission

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  1. Ebola (Ebola Virus Disease): Treatment

    Science.gov (United States)

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  2. Yeast for virus research

    Science.gov (United States)

    Zhao, Richard Yuqi

    2017-01-01

    Budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) are two popular model organisms for virus research. They are natural hosts for viruses as they carry their own indigenous viruses. Both yeasts have been used for studies of plant, animal and human viruses. Many positive sense (+) RNA viruses and some DNA viruses replicate with various levels in yeasts, thus allowing study of those viral activities during viral life cycle. Yeasts are single cell eukaryotic organisms. Hence, many of the fundamental cellular functions such as cell cycle regulation or programed cell death are highly conserved from yeasts to higher eukaryotes. Therefore, they are particularly suited to study the impact of those viral activities on related cellular activities during virus-host interactions. Yeasts present many unique advantages in virus research over high eukaryotes. Yeast cells are easy to maintain in the laboratory with relative short doubling time. They are non-biohazardous, genetically amendable with small genomes that permit genome-wide analysis of virologic and cellular functions. In this review, similarities and differences of these two yeasts are described. Studies of virologic activities such as viral translation, viral replication and genome-wide study of virus-cell interactions in yeasts are highlighted. Impacts of viral proteins on basic cellular functions such as cell cycle regulation and programed cell death are discussed. Potential applications of using yeasts as hosts to carry out functional analysis of small viral genome and to develop high throughput drug screening platform for the discovery of antiviral drugs are presented. PMID:29082230

  3. Viruses infecting marine molluscs.

    Science.gov (United States)

    Arzul, Isabelle; Corbeil, Serge; Morga, Benjamin; Renault, Tristan

    2017-07-01

    Although a wide range of viruses have been reported in marine molluscs, most of these reports rely on ultrastructural examination and few of these viruses have been fully characterized. The lack of marine mollusc cell lines restricts virus isolation capacities and subsequent characterization works. Our current knowledge is mostly restricted to viruses affecting farmed species such as oysters Crassostrea gigas, abalone Haliotis diversicolor supertexta or the scallop Chlamys farreri. Molecular approaches which are needed to identify virus affiliation have been carried out for a small number of viruses, most of them belonging to the Herpesviridae and birnaviridae families. These last years, the use of New Generation Sequencing approach has allowed increasing the number of sequenced viral genomes and has improved our capacity to investigate the diversity of viruses infecting marine molluscs. This new information has in turn allowed designing more efficient diagnostic tools. Moreover, the development of experimental infection protocols has answered some questions regarding the pathogenesis of these viruses and their interactions with their hosts. Control and management of viral diseases in molluscs mostly involve active surveillance, implementation of effective bio security measures and development of breeding programs. However factors triggering pathogen development and the life cycle and status of the viruses outside their mollusc hosts still need further investigations. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. On geographic barriers and Pleistocene glaciations: Tracing the diversification of the Russet-crowned Warbler (Myiothlypis coronata) along the Andes

    Science.gov (United States)

    2018-01-01

    We studied the phylogeography and plumage variation of the Russet-crowned Warbler (Myiothlypis coronata), from Venezuela to Bolivia, with focus on populations from Ecuador and northern Peru. We analyzed sequences of mitochondrial and nuclear genes, geographic distributions, as well as photographs of specimens deposited at museum collections. Phylogenetic analyses identified three major lineages formed by populations from: Venezuela and Colombia (M. c. regulus), Ecuador and northern Peru (M. elata, M. castaneiceps, M. orientalis, M. c. chapmani), and central Peru and Bolivia (M. c. coronata). We found further population structure within M. c. regulus and M. c. coronata, and population structure and complexity of plumage variation within the Ecuador-northern Peru lineage. Time-calibrated trees estimated that most intraspecific variation originated during the Pleistocene; however, this pattern may not be attributed to an increase in diversification rate during that period. We discuss these results in the context of the importance of geographic-ecological barriers in promoting lineage diversification along the Andes and put forward a preliminary taxonomic proposal for major lineages identified in this study. PMID:29522515

  5. K-Ar ages of rocks from Lago Alumine, Rucachoroi and Quillen, North Patagonian Andes, Neuquen, Republica Argentina

    International Nuclear Information System (INIS)

    Latorre, Carlos O.; Vattuone, M.E; Linares, Enrique; Leal, Pablo R

    2001-01-01

    This study presents new K-Ar ages of granitic rocks from the Patagonian Batholit in the North Patagonian Andes (38 o 00'- 39 o 30' SL), from localities near Alumine lake and from Norquinco lake to Quillen valley, in the Neuquen Province, Argentine. The granitic rocks of Patagonia had been recognized as Upper Paleozoic to Middle Jurassic batholits and as Late Jurassic to Tertiary batholiths (Rapela and Pankhurst, 1992). Geochronologically, Rapela and Kay (1988) had distinguished Early Cretaceous (140 to 120 Ma) and Late Cretaceous (110 to 75 Ma ) magmatic episodes based in potassium-argon data. For the granitic rocks of the area of Paso Icalma, Moquehue and the Rahue granodiorites, Cingolani et al. (1991) presented Rb-Sr whole rock isochron ages of 70±10 Ma, 209±13 Ma and 237±37 Ma, respectively, and Varela et al. (1994), with the same method, cited an age of 285±5 Ma for the Rahue granodiorites and diorites (au)

  6. Analyzing Multidecadal Trends in Cloudiness Over the Subtropical Andes Mountains of South America Using a Regional Climate Model.

    Science.gov (United States)

    Zaitchik, B. F.; Russell, A.; Gnanadesikan, A.

    2016-12-01

    Satellite-based products indicate that many parts of South America have been experiencing increases in outgoing longwave radiation (OLR) and corresponding decreases in cloudiness over the last few decades, with the strongest trends occurring in the subtropical Andes Mountains - an area that is highly vulnerable to climate change due to its reliance on glacial melt for dry-season runoff. Changes in cloudiness may be contributing to increases in atmospheric temperature, thereby raising the freezing level height (FLH) - a critical geophysical parameter. Yet these trends are only partially captured in reanalysis products, while AMIP climate models generally show no significant trend in OLR over this timeframe, making it difficult to determine the underlying drivers. Therefore, controlled numerical experiments with a regional climate model are performed in order to investigate drivers of the observed OLR and cloudiness trends. The Weather Research and Forecasting model (WRF) is used here because it offers several advantages over global models, including higher resolution - a critical asset in areas of complex topography - as well as flexible physics, parameterization, and data assimilation capabilities. It is likely that changes in the mean states and meridional gradients of SSTs in the Pacific and Atlantic oceans are driving regional trends in clouds. A series of lower boundary manipulations are performed with WRF to determine to what extent changes in SSTs influence regional OLR.

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

    Science.gov (United States)

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

    2014-10-01

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

  8. Total arsenic, lead, cadmium, copper, and zinc in some salt rivers in the northern Andes of Antofagasta, Chile.

    Science.gov (United States)

    Queirolo, F; Stegen, S; Mondaca, J; Cortés, R; Rojas, R; Contreras, C; Munoz, L; Schwuger, M J; Ostapczuk, P

    2000-06-08

    The pre-Andes water in the region of Antofagasta is the main drinking and irrigation water source for approximately 3000 Atacameña (indigenous) people. The concentration for soluble elements (filtration in field through a 0.45-microm filter) was: Cd < 0.1 ng/ml; Pb < 0.5 ng/ml; and Zn and Cu between 1 and 10 ng/ml. In particulate material the concentrations were: for Cd < 0.1 ng/ml; for Pb < 0.3 ng/ml; and for Zn and Cu less than 1 ng/ml. The total content of these elements is far below the international recommendations (WHO) and the national standards (N. Ch. 1333 mod. 1987 and 409-1 of 1984). On the other hand, in some rivers a very high arsenic concentration was found (up to 3000 ng/ml) which exceed more than 50 times the national standard. In order to verify the analytical results, inter-laboratory and comparison with different determination methods have been done.

  9. Snakes of an urban-rural landscape in the central Andes of Colombia: species composition, distribution, and natural history

    Directory of Open Access Journals (Sweden)

    Julián Andrés Rojas-Morales

    2012-12-01

    Full Text Available From 2005 to 2011, I studied the composition, distribution and natural history of an Andean urban-rural snake assemblage at the Cordillera Central of Colombia, based on three data sources: (1 examination of specimens in the MHN-UC [Museo de Historia Natural, Universidad de Caldas], (2 incidental encounters by author, and (3 collection of data by other researchers. Additionally, I provide natural history notes for the species involved. A total of 14 species, including two subspecies of snakes, belonging to 12 genera and four families, have been found in the studied area (municipality of Manizales, Caldas. Taking into account this total, 10 had atleast one record in the urban area, 13 in the rural area and 14 in forested areas. Only Liophis epinephelus bimaculatus was found exclusively in forest environment. Three species (21.4% are apparently endemic to the region, six species (42.8% correspond to afauna representative of the Tropical–Andean range of South America, four species (28.5% are distributed from Central America to the tropical Andes, and only one species is widely distributed in the whole continent. The snake assemblage in Manizales is mostly terrestrial, and in general, the species tend to be more active in the rainy periods of the year (mainly from October–December, and most of them may occasionally be found in urban areas, mainly close to areas of vegetation such as crops and pastures.

  10. Texture Analysis of satellite imagery in the field of biodiversity and forest structure of the Colombian Andes

    International Nuclear Information System (INIS)

    Anaya A, Jesus A; Duque L, Rosa A; Valencia H, German M

    2008-01-01

    The relationship between texture calculated from an Ikonos image with diversity and structure was evaluated along a corridor with 43 field plots in the Colombian Andes. Diversity indexes were calculated at the 43 plots and Land Use maps were used as an approach to vegetation structure. Texture was obtained from an Ikonos image using Gray Level Co-occurrence Matrix GLCM and Gray Level Difference Vector GLDV. Traditionally, texture has been interpreted from a qualitatively point of view from smooth to rough, however our approach using a matrix allows for a quantitative measurement. Texture was related to field information at two different detail levels: first with diversity measurements (Shannon Index and Richness) established at forest plots and second, with classes of a land use map (primary forest, secondary forests, forest plantation, crops and pastures) considered to be representative of vegetation structure. Results are based on relations between structure diversity,texture diversity and texture structure. Ikonos texture presents a large potential to classify forests at different successional stages however, the relation between diversity and data gathered with remote sensing is still weak. Landsat images are mentioned throughout the text as a reference or comparison with Ikonos images.

  11. The socioeconomic factors that facilitate or constrain restoration management: Watershed rehabilitation and wet meadow (bofedal) restoration in the Bolivian Andes.

    Science.gov (United States)

    Hartman, Brett D; Cleveland, David A

    2018-03-01

    Restoration ecology holds promise for addressing land degradation in impoverished rural environments, provided the approach is adapted to rural development settings. While there is a need for increased integration of social dynamics in land restoration, few systematic studies exist. We explored the socioeconomic factors that influence restoration management, including local motives and perceived benefits, incentives, land tenancy, institutional factors, conflict resolution, accessibility, off-farm labor, and outmigration. The study area is a successful watershed rehabilitation and wet meadow restoration project in the Bolivian Andes that began in 1992. We used household survey methods (n = 237) to compare the communities that had conducted the most restoration management with those that had conducted the least. Results suggest that several factors facilitate investments in land restoration, including aligning restoration objectives with local motives and perceived benefits, ensuring incentives are in place to stimulate long-term investments, conflict resolution, private land tenancy, and accessibility. However, higher levels of organization and active leadership can facilitate land restoration on communal lands. Increased livelihood benefits from land restoration helped slow the rate of rural to urban migration, with 24.5% outmigration in the highest restoration management communities compared to 62.1% in the lowest restoration management communities. Results suggest that land restoration projects that integrate community development into project planning and implementation will achieve greater success. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Moraine preservation and boulder erosion in the tropical Andes: interpreting old surface exposure ages in glaciated valleys

    Science.gov (United States)

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

    2005-10-01

    Cosmogenic dating provides a long-awaited means of directly dating glacial deposits that pre-date the last glacial cycle. Although the potential benefits of longer chronologies are obvious, the greater uncertainty associated with older cosmogenic ages may be less readily apparent. We illustrate the challenges of developing and interpreting a long chronology using our data from the Peruvian Andes. We used surface exposure dating with cosmogenic radionuclides (CRNs; 10Be and 26Al) to date 140 boulders on moraines in valleys bordering the Junin Plain (11° S, 76° W) in central Peru. Our chronology spans multiple glacial cycles and includes exposure ages greater than 1 million years, which indicate that long-term rates of boulder erosion have been very low. Interpreting the chronology of moraines for glaciations that predate the last glacial cycle is complicated by the need to consider boulder erosion and exhumation, surface uplift, and inheritance of CRNs from previous exposure intervals. As an example, we recalculate exposure ages using our boulder erosion rates (0.3-0.5 metres per million years) and estimated surface uplift rates to emphasise both the challenges involved in interpreting old surface exposure ages and the value of chronological data, even with large uncertainties, when reconstructing the palaeoclimate of a region.

  13. Quantifying impact reduction due to avoidance, minimization and restoration for a natural gas pipeline in the Peruvian Andes

    International Nuclear Information System (INIS)

    Sahley, C.T.; Vildoso, B.; Casaretto, C.; Taborga, P.; Ledesma, K.; Linares-Palomino, R.; Mamani, G.; Dallmeier, F.; Alonso, A.

    2017-01-01

    We present monitoring methods and quantitative biodiversity data to document components of the mitigation hierarchy. We estimated avoidance, minimization, restoration and impact reduction in quality hectares for the 25 m wide right of way of a 408 km natural gas buried pipeline that crosses 14 Ecological Landscape Units (ELUs) in the tropical Andes of Peru. We found that applying the mitigation hierarchy as part of a comprehensive biodiversity action plan substantially reduced impacts on biodiversity in all habitats studied. Avoidance and right of way minimization contributed to significant impact reduction. We quantified impact reduction during construction and operation on the right of way of the pipeline over a five-year period and found that restoration was the greatest contributor to reducing impacts. We documented that most ELUs have a positive restoration trajectory. We also documented how monitoring over large scale spatial scales, in combination with site-specific monitoring, generated data for management to determine restoration priorities and impact mitigation. A biodiversity action plan that incorporated the mitigation hierarchy and a science-based biodiversity monitoring and assessment program contributed to biodiversity management of the project and played an important role in minimizing and managing impacts. - Highlights: •Quantitative data for mitigation hierarchy components are presented. •Application of the mitigation hierarchy reduced impacts on biodiversity. •A biodiversity monitoring program provided data to reduce impacts.

  14. Native American gene continuity to the modern admixed population from the Colombian Andes: Implication for biomedical, population and forensic studies.

    Science.gov (United States)

    Criollo-Rayo, Angel A; Bohórquez, Mabel; Prieto, Rodrigo; Howarth, Kimberley; Culma, Cesar; Carracedo, Angel; Tomlinson, Ian; Echeverry de Polnaco, Maria M; Carvajal Carmona, Luis G

    2018-06-07

    Andean populations have variable degrees of Native American and European ancestry, representing an opportunity to study admixture dynamics in the populations from Latin America (also known as Hispanics). We characterized the genetic structure of two indigenous (Nasa and Pijao) and three admixed (Ibagué, Ortega and Planadas) groups from Tolima, in the Colombian Andes. DNA samples from 348 individuals were genotyped for six mitochondrial DNA (mtDNA), seven non-recombining Y-chromosome (NRY) region and 100 autosomal ancestry informative markers. Nasa and Pijao had a predominant Native American ancestry at the autosomal (92%), maternal (97%) and paternal (70%) level. The admixed groups had a predominant Native American mtDNA ancestry (90%), a substantial frequency of European NRY haplotypes (72%) and similar autosomal contributions from Europeans (51%) and Amerindians (45%). Pijao and nearby Ortega were indistinguishable at the mtDNA and autosomal level, suggesting a genetic continuity between them. Comparisons with multiple Native American populations throughout the Americas revealed that Pijao, had close similarities with Carib-speakers from distant parts of the continent, suggesting an ancient correlation between language and genes. In summary, our study aimed to understand Hispanic patterns of migration, settlement and admixture, supporting an extensive contribution of local Amerindian women to the gene pool of admixed groups and consistent with previous reports of European-male driven admixture in Colombia. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. The effect of highly variable topography on the spatial distribution of Aniba perutilis (Lauraceae in the Colombian Andes

    Directory of Open Access Journals (Sweden)

    José C. Fagua

    2013-03-01

    Full Text Available Topography is a factor that can significantly affect the diversity and the distribution of trees species in tropical forests. Aniba perutilis, a timber species listed as vulnerable to extinction, is widely distributed in Andean forest fragments, especially in those with highly variable topography. Based on field surveys and logistic regression analyses, we studied the population structure and the effect of highly variable topography on the spatial distribution of this tree in three protected forest fragments in the central Andes of Colombia. Individuals of A. perutilis were mainly found on mountain ridges and hills with gentle slopes; no individuals were found in valleys. Using a species distribution model with presence/absence data, we showed that the available habitat for A. perutilis is significantly smaller than the extension of the fragments and much smaller than the extension of the currently protected areas. Our results have important implications for the conservation of A. perutilis and likely for other threatened Andean tree species, which can also have locally restricted distributions due to highly variable local topography.

  16. Genetic structure of Quechua-speakers of the Central Andes and geographic patterns of gene frequencies in South Amerindian populations.

    Science.gov (United States)

    Luiselli, D; Simoni, L; Tarazona-Santos, E; Pastor, S; Pettener, D

    2000-09-01

    A sample of 141 Quechua-speaking individuals of the population of Tayacaja, in the Peruvian Central Andes, was typed for the following 16 genetic systems: ABO, Rh, MNSs, P, Duffy, AcP1, EsD, GLOI, PGM1, AK, 6-PGD, Hp, Gc, Pi, C3, and Bf. The genetic structure of the population was analyzed in relation to the allele frequencies available for other South Amerindian populations, using a combination of multivariate and multivariable techniques. Spatial autocorrelation analysis was performed independently for 13 alleles to identify patterns of gene flow in South America as a whole and in more specific geographic regions. We found a longitudinal cline for the AcP1*a and EsD*1 alleles which we interpreted as the result of an ancient longitudinal expansion of a putative ancestral population of modern Amerindians. Monmonnier's algorithm, used to identify areas of sharp genetic discontinuity, suggested a clear east-west differentiation of native South American populations, which was confirmed by analysis of the distribution of genetic distances. We suggest that this pattern of genetic structures is the consequence of the independent peopling of western and eastern South America or to low levels of gene flow between these regions, related to different environmental and demographic histories. Copyright 2000 Wiley-Liss, Inc.

  17. Rapid Geodetic Shortening Across the Eastern Cordillera of NW Argentina Observed by the Puna-Andes GPS Array

    Science.gov (United States)

    McFarland, Phillip K.; Bennett, Richard A.; Alvarado, Patricia; DeCelles, Peter G.

    2017-10-01

    We present crustal velocities for 29 continuously recording GPS stations from the southern central Andes across the Puna, Eastern Cordillera, and Santa Barbara system for the period between the 27 February 2010 Maule and 1 April 2014 Iquique earthquakes in a South American frame. The velocity field exhibits a systematic decrease in magnitude from 35 mm/yr near the trench to convergence accommodated at the subduction interface. Velocity residuals calculated for each model demonstrate that locking on the NZ-SA interface is insufficient to reproduce the observed velocities. We model deformation associated with a back-arc décollement using an edge dislocation, estimating model parameters from the velocity residuals for each forward model of the subduction interface ensemble using a Bayesian approach. We realize our best fit to the thrust-perpendicular velocity field with 70 ± 5% of NZ-SA convergence accommodated at the subduction interface and a slip rate of 9.1 ± 0.9 mm/yr on the fold-thrust belt décollement. We also estimate a locking depth of 14 ± 9 km, which places the downdip extent of the locked zone 135 ± 20 km from the thrust front. The thrust-parallel component of velocity is fit by a constant shear strain rate of -19 × 10-9 yr-1, equivalent to clockwise rigid block rotation of the back arc at a rate of 1.1°/Myr.

  18. High-Resolution ∂18O record of middle-late Holocene hydrologic variability from the central Peruvian Andes (Invited)

    Science.gov (United States)

    Rodbell, D. T.; Abbott, M.; Bird, B. W.; Stansell, N.

    2009-12-01

    Laguna Yuraicocha in the western cordillera of the central Peruvian Andes (12.53°S; 75.50°W; 4460 masl) is dammed by late glacial moraines and is underlain and surrounded by Jurassic and Cretaceous limestone interbedded with siliciclastic rocks. A 6.9 meter-long sediment core from the distal end of the lake is dominated by authigenic calcite (marl) with a mean concentration of 82 weight percent that has accumulated at a rate of ~ 1 mm yr-1 for the past 6200 years. The age model for the core is based on a combination of 210Pb and AMS 14C ages from charcoal; modern lake water is ~1‰ evaporatively enriched from mean regional precipitation. Marl samples were taken with an average sampling interval of 8 years; samples were treated to remove organic matter, sieved to concentrate the clay fraction was removed by repeated pipette withdrawal. The Peru and Bolivia, are especially sensitive to changes in regional moisture balance.

  19. Arquitectura precerámica en la cordillera de los Andes, Piruru frene a la diversidad de los datos

    Directory of Open Access Journals (Sweden)

    Elisabeth Bonnier

    1988-12-01

    Full Text Available Los datos sobre la arquitectura precerámica en la cordilleraandina provienen de cinco sitios: La Galgada, Piruru, Huaricoto, Shillacotoy Kotosh. Contexto arqueológico y rasgos arquitectónicos específicos permitenidentificar la función ceremonial de esta arquitectura. La descripciónde las construcciones religiosas pone en evidencia un conjunto pertinente decaracteres comunes. El espacio ceremonial, construido y sin construir, se articulaalrededor del doble elemento arquitectónico fundamental, el fogón yel piso. Para analizar el piso a dos niveles, dos neologismos, pericausto y epicaustohan sido creados. El análisis arquitectónico muestra que el piso es elespacio sagrado por excelencia. Los fechados 14C de los sitios estudiadosdestacan la larga duración del Precerámico Final con arquitectura. A la luz delos últimos trabajos en Piruru y de los cambios arquitectónicos perceptiblesen este sitio, la hipótesis, formulada a principios de este decenio, sobre ·taexistencia de una tradición religiosa única propia de los Andes Centrales, seestá reconsiderando.

  20. PHYTOSOCIOLOGY OF WEEDS AFTER POTATO CULTIVATION (Solanum tuberosum L. IN THE VENEZUELAN ANDES:AN AGROECOLOGICAL APPROACH

    Directory of Open Access Journals (Sweden)

    Pedro Manuel Villa

    2017-08-01

    Full Text Available Weeds represent one problem for potato cultivation in the Venezuelan Andes; however ecological studies to improve their management are limited. This study has aimed to carry out a phytosociological survey of weed community after potato cultivation in Mérida, Mérida state, Venezuela. The experiment was carried out under a completely randomized design with 20 plots (2x2 m. The weeds surveys were conducted at two month intervals, randomly selecting five plots per session during June 2006 and February 2007, to 60 days after cultivation (DDC, 120, 180, and 240 DDC. The phytosociological survey was performed involving identification and quantification of numbers of individuals the weeds in each plot. After were estimated of phytosociological parameters such as density, frequency, abundance to calculate the importance value index. A multivariate non-metric multidimensional scaling (NMDS was performed using species abundances; also was used the unweighted pair group method with arithmetic mean (UPGMA with presence absence data. Seventeen families, 32 genera and 35 species of weeds were identified, with the Asteraceae, Fabaceae and Poaceae families showed higher importance within the community. The most important species in the all stages were Pennisetum clandestinum, Paspalum decumbens, Desmodium adscendens, Aldama dentata, Borreria laevis, and Jaegeria hirta. Significant differences in phytosociological parameters were observed among weed species at each stage and among the different stages after potato cultivation.

  1. A Stepwise, Participatory Approach to Design and Implement Community Based Adaptation to Drought in the Peruvian Andes

    Directory of Open Access Journals (Sweden)

    Ralph Lasage

    2015-02-01

    Full Text Available The livelihoods of people in the Andes are expected to be affected by climate change due to their dependence on glacier water. The observed decrease in glacier volume over the last few decades is likely to accelerate during the current century, which will affect water availability in the region. This paper presents an approach for participatory development of community-based adaptation measures to cope with the projected impacts of climate change. It combines in an innovative manner participatory design with physical measurements, modeling and a vulnerability analysis. Vulnerability to drought is made operational for households in a catchment of the Ocoña River basin in Peru. On the basis of a household survey (n = 94 we explore how a vulnerability index (risk divided by response efficacy can be used to assess the distribution of vulnerability over households, and how socio-economic factors determine this vulnerability. Water entitlement, area of irrigated land, income and education are all significantly correlated with vulnerability to drought. The research showed that the main source of spring water is local rainwater, and that water use efficiency is low. The selected adaptation measures aimed to increase water availability close to farmland, and increase water use efficiency of farmers and households.

  2. Comparison of Three Supervised Learning Methods for Digital Soil Mapping: Application to a Complex Terrain in the Ecuadorian Andes

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    Martin Hitziger

    2014-01-01

    Full Text Available A digital soil mapping approach is applied to a complex, mountainous terrain in the Ecuadorian Andes. Relief features are derived from a digital elevation model and used as predictors for topsoil texture classes sand, silt, and clay. The performance of three statistical learning methods is compared: linear regression, random forest, and stochastic gradient boosting of regression trees. In linear regression, a stepwise backward variable selection procedure is applied and overfitting is controlled by minimizing Mallow’s Cp. For random forest and boosting, the effect of predictor selection and tuning procedures is assessed. 100-fold repetitions of a 5-fold cross-validation of the selected modelling procedures are employed for validation, uncertainty assessment, and method comparison. Absolute assessment of model performance is achieved by comparing the prediction error of the selected method and the mean. Boosting performs best, providing predictions that are reliably better than the mean. The median reduction of the root mean square error is around 5%. Elevation is the most important predictor. All models clearly distinguish ridges and slopes. The predicted texture patterns are interpreted as result of catena sequences (eluviation of fine particles on slope shoulders and landslides (mixing up mineral soil horizons on slopes.

  3. Evolutionary persistence in Gunnera and the contribution of southern plant groups to the tropical Andes biodiversity hotspot

    Directory of Open Access Journals (Sweden)

    Christine D. Bacon

    2018-03-01

    Full Text Available Several studies have demonstrated the contribution of northern immigrants to the flora of the tropical Andes—the world’s richest and most diverse biodiversity hotspot. However, much less is known about the biogeographic history and diversification of Andean groups with southern origins, although it has been suggested that northern and southern groups have contributed roughly equally to the high Andean (i.e., páramo flora. Here we infer the evolutionary history of the southern hemisphere plant genus Gunnera, a lineage with a rich fossil history and an important ecological role as an early colonising species characteristic of wet, montane environments. Our results show striking contrasts in species diversification, where some species may have persisted for some 90 million years, and whereas others date to less than 2 Ma since origination. The outstanding longevity of the group is likely linked to a high degree of niche conservatism across its highly disjunct range, whereby Gunnera tracks damp and boggy soils in cool habitats. Colonisation of the northern Andes is related to Quaternary climate change, with subsequent rapid diversification appearing to be driven by their ability to take advantage of environmental opportunities. This study demonstrates the composite origin of a mega-diverse biota.

  4. On geographic barriers and Pleistocene glaciations: Tracing the diversification of the Russet-crowned Warbler (Myiothlypis coronata) along the Andes.

    Science.gov (United States)

    Prieto-Torres, David A; Cuervo, Andrés M; Bonaccorso, Elisa

    2018-01-01

    We studied the phylogeography and plumage variation of the Russet-crowned Warbler (Myiothlypis coronata), from Venezuela to Bolivia, with focus on populations from Ecuador and northern Peru. We analyzed sequences of mitochondrial and nuclear genes, geographic distributions, as well as photographs of specimens deposited at museum collections. Phylogenetic analyses identified three major lineages formed by populations from: Venezuela and Colombia (M. c. regulus), Ecuador and northern Peru (M. elata, M. castaneiceps, M. orientalis, M. c. chapmani), and central Peru and Bolivia (M. c. coronata). We found further population structure within M. c. regulus and M. c. coronata, and population structure and complexity of plumage variation within the Ecuador-northern Peru lineage. Time-calibrated trees estimated that most intraspecific variation originated during the Pleistocene; however, this pattern may not be attributed to an increase in diversification rate during that period. We discuss these results in the context of the importance of geographic-ecological barriers in promoting lineage diversification along the Andes and put forward a preliminary taxonomic proposal for major lineages identified in this study.

  5. Pepino mosaic virus

    NARCIS (Netherlands)

    Vlugt, van der R.A.A.

    2009-01-01

    Pepino mosaic virus (PepMV) is a relatively new plant virus that has become a signifi cant agronomical problem in a relatively short period of time. It is a member of the genus Potexvirus within the family Flexiviridae and is readily mechanically transmissible. It is capable of infecting tomato

  6. Avian influenza virus

    Science.gov (United States)

    Avian influenza virus (AIV) is type A influenza that is adapted to avian host species. Although the virus can be isolated from numerous avian species, the natural host reservoir species are dabbling ducks, shorebirds and gulls. Domestic poultry species (poultry being defined as birds that are rais...

  7. Hepatitis viruses overview

    African Journals Online (AJOL)

    Hepatitis is major cause of morbidity or mortality worldwide, particularly in the developing world. The major causes of infective hepatitis are hepatitis viruses. A, B, C, D or E. In the acute phase, there are no clinical features that can reliably differentiate between these viruses. Infection may be asymptomatic or can present as.

  8. Viral Haemorrhagic Septicaemia Virus

    DEFF Research Database (Denmark)

    Olesen, Niels Jørgen; Skall, Helle Frank

    2013-01-01

    This chapter covers the genetics (genotypes and serotypes), clinical signs, host species, transmission, prevalence, diagnosis, control and prevention of viral haemorrhagic septicaemia virus.......This chapter covers the genetics (genotypes and serotypes), clinical signs, host species, transmission, prevalence, diagnosis, control and prevention of viral haemorrhagic septicaemia virus....

  9. Tobacco ringspot virus

    Science.gov (United States)

    Tobacco ringspot virus (TRSV), and its vector, the dagger nematodes (Xiphinema americanum and related species) are widely distributed throughout the world. Cucumber, melon, and watermelon are particularly affected by TRSV. Symptoms can vary with plant age, the strain of the virus, and environment...

  10. Respiratory Syncytial Virus (RSV)

    Centers for Disease Control (CDC) Podcasts

    Respiratory Syncytial Virus, or RSV, causes cold-like symptoms but can be serious for infants and older adults. In this podcast, CDC’s Dr. Eileen Schneider discusses this common virus and offers tips to prevent its spread.

  11. Viruses in reptiles.

    Science.gov (United States)

    Ariel, Ellen

    2011-09-21

    The etiology of reptilian viral diseases can be attributed to a wide range of viruses occurring across different genera and families. Thirty to forty years ago, studies of viruses in reptiles focused mainly on the zoonotic potential of arboviruses in reptiles and much effort went into surveys and challenge trials of a range of reptiles with eastern and western equine encephalitis as well as Japanese encephalitis viruses. In the past decade, outbreaks of infection with West Nile virus in human populations and in farmed alligators in the USA has seen the research emphasis placed on the issue of reptiles, particularly crocodiles and alligators, being susceptible to, and reservoirs for, this serious zoonotic disease. Although there are many recognised reptilian viruses, the evidence for those being primary pathogens is relatively limited. Transmission studies establishing pathogenicity and cofactors are likewise scarce, possibly due to the relatively low commercial importance of reptiles, difficulties with the availability of animals and permits for statistically sound experiments, difficulties with housing of reptiles in an experimental setting or the inability to propagate some viruses in cell culture to sufficient titres for transmission studies. Viruses as causes of direct loss of threatened species, such as the chelonid fibropapilloma associated herpesvirus and ranaviruses in farmed and wild tortoises and turtles, have re-focused attention back to the characterisation of the viruses as well as diagnosis and pathogenesis in the host itself.

  12. ICTV Virus Taxonomy Profile

    DEFF Research Database (Denmark)

    Simmonds, Peter; Becher, Paul; Bukh, Jens

    2017-01-01

    The Flaviviridae is a family of small enveloped viruses with RNA genomes of 9000-13 000 bases. Most infect mammals and birds. Many flaviviruses are host-specific and pathogenic, such as hepatitis C virus in the genus Hepacivirus. The majority of known members in the genus Flavivirus are arthropod...

  13. ICTV virus taxonomy profile

    NARCIS (Netherlands)

    Purdy, Michael A.; Harrison, Tim J.; Jameel, S.; Meng, X.J.; Okamoto, H.; Poel, Van Der W.H.M.; Smith, Donald B.; Lefkowitz, Elliot J.; Davison, Andrew J.; Siddell, Stuart G.; Simmonds, Peter; Adams, Michael J.; Smith, Donald B.; Orton, Richard J.; Knowles, Nick J.

    2017-01-01

    The family Hepeviridae includes enterically transmitted small non-enveloped positive-sense RNA viruses. It includes the genera Piscihepevirus, whose members infect fish, and Orthohepevirus, whose members infect mammals and birds. Members of the genus Orthohepevirus include hepatitis E virus, which

  14. Viruses of the Archaea

    DEFF Research Database (Denmark)

    Prangishvili,, David; Basta, Tamara; Garrett, Roger Antony

    2016-01-01

    Viruses infecting members of Archaea, the third domain of life, constitute an integral, yet unique part of the virosphere. Many of these viruses, specifically the species that infect hyperthermophilic hosts, display morphotypes – for example, bottle shaped, spindle shaped, droplet shaped, coil sh...

  15. Strategy as a Virus

    DEFF Research Database (Denmark)

    Obed Madsen, Søren

    This article is based on virus theory (Røvik, 2007, 2011), and proposes to develop a framework that defines technology as a virus that penetrates the organism of an organization. The framework develops a new vocabulary, which can help in analyzing technologies and their negative effects on actors...... and organizations. In this paper, the virus theory is used to analyze a strategy process in an organization as an example of a technology. It shows how the strategy over time creates a memory loss, where the managers who are exposed to the virus forget their critique of the new strategy concept. The article also...... shows how resistant can be understood as being immune to a virus, since the strategy concepts bears resemblance to a former strategy concept. The article also argues that there should be more focus on the negative impacts of management tool and especially how organizations and managers are dealing...

  16. How do two Lupinus species respond to temperature along an altitudinal gradient in the Venezuelan Andes? ¿Cómo responden dos especies de Lupinus a la temperatura en un gradiente altitudinal en los Andes venezolanos?

    Directory of Open Access Journals (Sweden)

    FERMÍN RADA

    2008-09-01

    Full Text Available Temperature determines plant formations and species distribution along altitudinal gradients. Plants in the tropical high Andes, through different physiological and morphological characteristics, respond to freezing night temperatures and high daytime energy inputs which occur anytime of the year. The main objective of this study was to characterize day and night temperature related responses of two Lupinus species with different altitudinal ranges (L. meridanus, 1,800-3,600 and L. eromonomos, 3,700-4,300 m of altitude. Are there differences in night low temperature resistance mechanisms between the species along the gradient? How do these species respond, in terms of optimum temperature for photosynthesis, to increasing altitude? Lupinus meridanus shows frost avoidance, in contrast to L. eromonomos, which tolerates freezing at higher altitudes. Optimum temperature for photosynthesis decreases along the gradient for both species. Maximum C0(2 assimilation rates were higher in L. meridanus, while L. eromonomos showed decreasing C0(2 assimilation rates at the higher altitude. In most cases, measured daily leaf temperature is always within the 80 % of optimum for photosynthesis. L. meridanus7 upper distribution limit seems to be restricted by cold resistance mechanisms, while L. eromonomos7 to a combination of both cold resistance and to C0(2 assimilation responses at higher altitudes.La temperatura determina las formaciones vegetales y la distribución de especies a lo largo de gradientes altitudinales. Las plantas en los altos Andes tropicales, a través de diferentes características morfológicas y fisiológicas, responden a temperaturas congelantes nocturnas y altas entradas energéticas durante el día en cualquier momento del año. El objetivo principal de este estudio fue caracterizar las respuestas relacionadas con temperaturas diurnas y nocturnas en dos especies de Lupinus con diferente distribución altitudinal (L. meridanus, 1

  17. Facies volcánicas del depósito de avalancha de detritos del volcán Tata Sabaya, Andes Centrales Volcanic facies of the debris avalanche deposit of Tata Sabaya Volcano, Central Andes

    Directory of Open Access Journals (Sweden)

    Benigno Godoy

    2012-09-01

    Full Text Available Las avalanchas de detritos, asociadas a colapsos parciales de edificios volcánicos, son fenómenos comunes en la evolución de un volcán. Este tipo de flujos son por inestabilidades, que pueden deberse a factores tales como la existencia de zonas afectadas por alteración hidrotermal, cambios climáticos, terremotos, intrusión de magmas en zonas superficiales (criptodomos y/o diques y/o movimiento de fallas bajo el edificio volcánico o cercanas a él. El producto final de estos flujos -denominado depósito de avalancha de detritos (DAD- presenta morfologías típicas de cerrillos y drenajes cerrados. En los Andes Centrales se han reconocido, al menos, 14 centros volcánicos con depósitos de avalancha asociados, entre los que está el volcán Tata Sabaya (Bolivia. El colapso que ha dado origen a este depósito podría haberse generado por una combinación de actividad sísmica y magmática en el volcán. El depósito asociado al colapso parcial de este volcán se distribuye sobre la parte baja del flanco sur del volcán y sobre la parte noroccidental de la cuenca del salar de Coipasa. Cubre una superficie de más de 230 km² y tiene un volumen estimado de 6±1 km³. Sobre la base de las composiciones litológicas, se ha establecido que el depósito está constituido por 6 tipos distintos de cerrillos, los cuales son: lávicos, piroclásticos, sedimentarios mixtos, brecha piroclástica y andesítico-basálticos. Considerando el tipo predominante de cerrillos y su distribución espacial dentro del depósito, se ha definido 6 facies diferentes (Facies de Bloques Toreva, Facies de Cerrillos Volcánicos, Facies Central, Facies de Cerrillos Sedimentarios, Facies Mixta y Facies de Cerrillos de Brecha Piroclástica. Tomando en cuenta la distribución espacial de estas facies, se propone la estructura del paleovolcán previa a su colapso parcial.Debris avalanches associated with partial sector collapse of volcanic edifices are common phenomena in the

  18. LA CUEVA ALIHUÉN, NUEVOS REGISTROS DE PINTURAS RUPESTRES EN LA VEGA DE MAIPÚ (SAN MARTÍN DE LOS ANDES, PATAGONIA, ARGENTINA (The Alihuén Cave, New Records of Cave Paintings in the Maipú Valley (San Martín de los Andes, Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    Alberto Enrique Pérez

    2014-06-01

    Full Text Available Se presenta el resultado de las nuevas investigaciones de pinturas rupestres en la vega Maipú, San Martín de los Andes, Neuquén, Argentina; donde se destaca la presencia de motivos zoomorfos, especialmente camélidos, de escasa representación hasta la fecha en el registro zooarqueológico local. El sitio Cueva Alihuén amplía la diversidad de motivos y técnicas de las pinturas rupestres de la vega Maipú, lo que nos permite plantear aspectos tanto biogeográficos respecto a la fauna como sobre la circulación de información y movilidad. Ambos aspectos nos permiten, nuevamente, aunar ambas vertientes de la cordillera de los Andes, compartiendo, integrando y complementando cada vez más características con el resto de los sitios que componen la cuenca hidrográfica de Valdivia, cuyo sector inferior constituye nuestra área de estudio. ENGLISH: New results from research on the cave paintings of the Maipú Valley, San Martín de los Andes, Neuquén, Argentina, highlight the presence of zoomorphic motifs, especially camelids which have been underrepresented in the local zooarchaeological record. The Alihuén cave site expands the range of motifs and techniques known from the cave paintings of the Maipú Valley that allows us to raise issues regarding both biogeographic wildlife, and on the flow of information and human mobility. These aspects allow us to share and integrate the increasingly complementary features on both sides of the Andes with the rest of the sites that comprise the Valdivia River basin, whose lower section composed our study area.

  19. Multiproxy Holocene paleoclimate records from the southern Peruvian Andes - what new can we learn from the stable carbon isotope composition of high altitude organic matter deposits?

    Science.gov (United States)

    Skrzypek, Grzegorz; Engel, Zbyněk

    2015-04-01

    Interpretation of the Central Andean paleoclimate over the last millennia still represents a research challenge demanding deeper studies [1,2]. Several high-resolution paleoclimate proxies for the last 10,000 years have been developed for the northern hemisphere. However, similar proxies are very limited for South America, particularly for high altitudes where, for example, tree-ring chronologies are not available and instrumental records are very limited. Consequently, our knowledge of high altitude climate changes in arid regions of the Peruvian Andes mainly relies on ice-core and lake deposit studies. In our study, we used a new alternative proxy for interpretation of palaeoclimate conditions based on a peat core taken from the Carhuasanta Valley at the foot of Nevado Mismi in the southern Peruvian Andes (15° 30'S, 71° 43'W, 4809m a.s.l.). The stable carbon isotope composition (δ13C) of Distichia peat reflects mainly the relative variation of the mean air temperature during subsequent growing seasons [3], and allows reconstructions of palaeotemperature changes. In contrast, peat organic carbon concentration (C % wt) records mainly wetness in the valley, directly corresponding to the changes in runoff in the upper part of the catchment. The most prominent climate changes recorded in the peat over last 4ka occurred between 3040 and 2750 cal. yrs BP. The initial warming turned to a very rapid cooling to temperatures at least 2° C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP, when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes that match the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years, when

  20. Computer Viruses: Pathology and Detection.

    Science.gov (United States)

    Maxwell, John R.; Lamon, William E.

    1992-01-01

    Explains how computer viruses were originally created, how a computer can become infected by a virus, how viruses operate, symptoms that indicate a computer is infected, how to detect and remove viruses, and how to prevent a reinfection. A sidebar lists eight antivirus resources. (four references) (LRW)

  1. Genetic continuity after the collapse of the Wari empire: mitochondrial DNA profiles from Wari and post-Wari populations in the ancient Andes.

    Science.gov (United States)

    Kemp, Brian M; Tung, Tiffiny A; Summar, Marshall L

    2009-09-01

    The Wari empire flourished in the central, highland Peruvian Andes from AD 600-1000, and although the events that led to its demise are unknown, archaeological evidence indicates that Wari control waned at the end of the first millennium. Here, we test the hypothesis that, despite the major shift in social and political organization at the fall of the Wari empire, the mitochondrial DNA (mtDNA) composition of populations from the Ayacucho Basin, the former imperial heartland of the empire, remained essentially unchanged. Results show that mtDNA haplogroup frequencies among the Wari and post-Wari groups differ, but the difference is not statistically significant (chi2 = 5.886, df = 3, P = 0.1172). This is the first study in the Andes to use haplotypic data to evaluate the observed genetic distance between two temporally distinct prehispanic populations (F(ST) = 0.029) against modeled expectations of four possible evolutionary scenarios. None of these simulations allowed the rejection of continuity. In total, at both the haplogroup and haplotype levels these data do not allow us to reject the hypothesis that post-Wari individuals sampled in this study are the maternal descendants of those sampled from the Wari era site of Conchopata. However, genetic homogeneity in the mitochondrial gene pool, as seen in the late prehispanic southern Andes, may also characterize our study region. But, prior to this research, this was unknown. If our new data show mtDNA homogeneity, then this could limit the detection of female migration if, in fact, it occurred. Nonetheless, the novel mtDNA data presented here currently do not support the hypothesis that there was an influx of genetically distinct females into the former Wari heartland after the Wari collapse. Copyright 2009 Wiley-Liss, Inc.

  2. Unraveling the diversification history of grasshoppers belonging to the “Trimerotropis pallidipennis” (Oedipodinae: Acrididae species group: a hotspot of biodiversity in the Central Andes

    Directory of Open Access Journals (Sweden)

    Noelia Verónica Guzmán

    2017-09-01

    Full Text Available The Andean Mountain range has been recognized as one of the biodiversity hotspots of the world. The proposed mechanisms for such species diversification, among others, are due to the elevation processes occurring during the Miocene and the intensive glacial action during the Pleistocene. In this study we investigated the diversification history of the grasshopper Trimerotropis pallidipennis species complex which shows a particularly wide latitudinal and altitudinal distribution range across the northern, central and southern Andes in South America. Many genetic lineages of this complex have been so far discovered, making it an excellent model to investigate the role of the central Andes Mountains together with climatic fluctuations as drivers of speciation. Phylogenetics, biogeographic and molecular clock analyses using a multi-locus dataset revealed that in Peru there are at least two, and possibly four genetic lineages. Two different stocks originated from a common ancestor from North/Central America—would have dispersed toward southern latitudes favored by the closure of the Panama Isthmus giving rise to two lineages, the coastal and mountain lineages, which still coexist in Peru (i.e., T. pallidipennis and T. andeana. Subsequent vicariant and dispersal events continued the differentiation process, giving rise to three to six genetic lineages (i.e., clades detected in this study, which were geographically restricted to locations dispersed over the central Andes Mountains in South America. Our results provide another interesting example of “island diversification” motored by the topography plus unstable climatic conditions during the Pleistocene, pointing out the presence of a hotspot of diversification in the Andean region of Peru.

  3. The high Andes, gene flow and a stable hybrid zone shape the genetic structure of a wide-ranging South American parrot

    Directory of Open Access Journals (Sweden)

    Schaefer H Martin

    2011-06-01

    Full Text Available Abstract Background While the gene flow in some organisms is strongly affected by physical barriers and geographical distance, other highly mobile species are able to overcome such constraints. In southern South America, the Andes (here up to 6,900 m may constitute a formidable barrier to dispersal. In addition, this region was affected by cycles of intercalating arid/moist periods during the Upper/Late Pleistocene and Holocene. These factors may have been crucial in driving the phylogeographic structure of the vertebrate fauna of the region. Here we test these hypotheses in the burrowing parrot Cyanoliseus patagonus (Aves, Psittaciformes across its wide distributional range in Chile and Argentina. Results Our data show a Chilean origin for this species, with a single migration event across the Andes during the Upper/Late Pleistocene, which gave rise to all extant Argentinean mitochondrial lineages. Analyses suggest a complex population structure for burrowing parrots in Argentina, which includes a hybrid zone that has remained stable for several thousand years. Within this zone, introgression by expanding haplotypes has resulted in the evolution of an intermediate phenotype. Multivariate regressions show that present day climatic variables have a strong influence on the distribution of genetic heterogeneity, accounting for almost half of the variation in the data. Conclusions Here we show how huge barriers like the Andes and the regional environmental conditions imposed constraints on the ability of a parrot species to colonise new habitats, affecting the way in which populations diverged and thus, genetic structure. When contact between divergent populations was re-established, a stable hybrid zone was formed, functioning as a channel for genetic exchange between populations.

  4. Influences of the ENSO, oscillation Madden-Julian, waves of the east, hurricanes and moon phases on the diurnal cycle of precipitation at the tropical Andes of Colombia

    International Nuclear Information System (INIS)

    Poveda, German; Mesa, Oscar; Agudelo, Paula; Alvarez, Juan; Arias, Paola; Moreno, Hernan; Salazar, Luis; Toro, Vladimir; Vieira, Sara

    2002-01-01

    We study the effects of large-scale ocean-atmospheric, astronomic phenomena on the diurnal cycle of precipitation at the tropical Andes of Colombia. Such phenomena include both phases of El Nino/Southern Oscillation (ENSO), namely El Nino and La Nina, the intra seasonal Madden-Julian oscillation, tropical easterly waves (4-8 days), moon phases and hurricanes over the Atlantic and eastern pacific oceans. We found a clear-cut effect of both ENSO phases: El Nino is associated with a diminished rainfall diurnal cycle, and La Nina intensifies it. Thus, ENSO modulates precipitation in Colombia at timescales ranging from hours to decades. We identified a close association with different phases of the Madden-Julian oscillation, as the diurnal cycle is intensified (larger amplitude) during its westerly phase, but it gets decreased during its easterly phase. For both ENSO and the Madden-Julian oscillation we identified a clear-cut influence on the amplitude of the diurnal cycle, yet the phase is conserved for the most part. Tropical easterly waves appear to affect the diurnal cycle, but no clear overall signal is pervasive throughout the region. We al so found a significant statistical association with hurricanes occurring over the northeastern pacific ocean with the diurnal cycle of precipitation at rain gages located over the eastern slope of the eastern range of the Colombian Andes. Rainfall at all the remaining slopes of the Andes is statistically associated with hurricanes occurring at the tropical north Atlantic and the Caribbean Sea. Moon phases are not statistically associated with the diurnal cycle and daily total rainfall

  5. Zika virus infection: a public health emergency!

    OpenAIRE

    Qureshi, Muhammad Salman Haider; Qureshi, Bakhtawar Wajeeha; Khan, Ramsha

    2017-01-01

    Zika virus belongs to the family of Flaviviridae. The Flaviviridae family also includes other human pathogens like West Nile virus (WNV), Yellow fever virus (YFV), mosquito transmitted Dengue virus (DENV), Tick borne encephalitic virus (TBEV) and Japanese encephalitis virus (JEV). Zika virus is a mosquito-borne disease and is transmitted by Aedes aegypti mosquito.

  6. Utilizing NASA Earth Observations to Model Volcanic Hazard Risk Levels in Areas Surrounding the Copahue Volcano in the Andes Mountains

    Science.gov (United States)

    Keith, A. M.; Weigel, A. M.; Rivas, J.

    2014-12-01

    Copahue is a stratovolcano located along the rim of the Caviahue Caldera near the Chile-Argentina border in the Andes Mountain Range. There are several small towns located in proximity of the volcano with the two largest being Banos Copahue and Caviahue. During its eruptive history, it has produced numerous lava flows, pyroclastic flows, ash deposits, and lahars. This isolated region has steep topography and little vegetation, rendering it poorly monitored. The need to model volcanic hazard risk has been reinforced by recent volcanic activity that intermittently released several ash plumes from December 2012 through May 2013. Exposure to volcanic ash is currently the main threat for the surrounding populations as the volcano becomes more active. The goal of this project was to study Copahue and determine areas that have the highest potential of being affected in the event of an eruption. Remote sensing techniques were used to examine and identify volcanic activity and areas vulnerable to experiencing volcanic hazards including volcanic ash, SO2 gas, lava flow, pyroclastic density currents and lahars. Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Landsat 8 Operational Land Imager (OLI), EO-1 Advanced Land Imager (ALI), Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Shuttle Radar Topography Mission (SRTM), ISS ISERV Pathfinder, and Aura Ozone Monitoring Instrument (OMI) products were used to analyze volcanic hazards. These datasets were used to create a historic lava flow map of the Copahue volcano by identifying historic lava flows, tephra, and lahars both visually and spectrally. Additionally, a volcanic risk and hazard map for the surrounding area was created by modeling the possible extent of ash fallout, lahars, lava flow, and pyroclastic density currents (PDC) for future eruptions. These model results were then used to identify areas that should be prioritized for disaster relief and evacuation orders.

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

    Science.gov (United States)

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

    2014-12-01

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

  8. Where There's Smoke: Using Satellites to Monitor Impact of Human Activities on Agriculture and Glaciers in the Andes and Himalayas

    Science.gov (United States)

    McCarty, J. L.; Banach, D. M.

    2017-12-01

    Burning of agricultural fields are important sources of black carbon deposition on mountain glaciers in the Andes and Himalayas. Fire is commonly used to support agricultural and pasture management, specifically to remove excess crop residue and other agricultural waste, but these fires can spread into wildland areas during the dry season. Occasionally, agricultural burning causes extreme air pollution events, like occurred in New Delhi, India in October 2016. Satellite data provides a monitoring method of human-caused fire near glaciers that is open-source, easily replicable, and free- to low-cost. We will be able to determine if the climate-smart intervention strategies have reduced or eliminated open burning in these glacier-adjacent agricultural regions. Historic fire and fire emission records have been constructed for the Andean and Himalayan regions, with finer-scale assessments of the regions where farm-level training for conservation agriculture and no-burn techniques are taking place, going back to 2003. Present-day and future (2017-2020) fires and emissions will be mapped and recorded to compare to the historical record, providing an independent assessment and monitoring of how effective the no-burn climate-smart agriculture intervention strategies are at the farm-, village-, region-, and country-level. We can then compare this with our ground-based observations from regional partners for further verification. Using geospatial and geoscience data and methods is important for the success of this project and allows for full transparency of the effectiveness of climate-smart agricultural interventions to improve crop yields for farmers in South America and South Asia while also slowing the melt of the Third Pole.

  9. High-Resolution Modeling of ENSO-Induced Precipitation in the Tropical Andes: Implications for Proxy Interpretation.

    Science.gov (United States)

    Kiefer, J.; Karamperidou, C.

    2017-12-01

    Clastic sediment flux into high-elevation Andean lakes is controlled by glacial processes and soil erosion caused by high precipitation events, making these lakes suitable archives of past climate. To wit, sediment records from Laguna Pallcacocha in Ecuador have been interpreted as proxies of ENSO variability, owing to increased precipitation in the greater region during El Niño events. However, the location of the lake's watershed, the presence of glaciers, and the different impacts of ENSO on precipitation in the eastern vs western Andes have challenged the suitability of the Pallcacocha record as an ENSO proxy. Here, we employ WRF, a high-resolution regional mesoscale weather prediction model, to investigate the circulation dynamics, sources of moisture, and resulting precipitation response in the L. Pallcacocha region during different flavors of El Niño and La Niña events, and in the presence or absence of ice caps. In patricular, we investigate Eastern Pacific (EP), Central Pacific (CP), coastal El Niño, and La Niña events. We validate the model simulations against spatially interpolated station measurements and reanalysis data. We find that during EP events, moisture is primarily advected from the Pacific, whereas during CP events, moisture primarily originates from the Atlantic. More moisture is available during EP events, which implies higher precipitation rates. Furthermore, we find that precipitation during EP events is mostly non-convective in contrast to primarily convective precipitation during CP events. Finally, a synthesis of the sedimentary record and the EP:CP ratio of accumulated precipitation and specific humidity in the L. Pallcacocha region allows us to assess whether past changes in the relative frequency of the two ENSO flavors may have been recorded in paleoclimate archives in this region.

  10. Hydrological and Geoelectrical monitoring of Landslides in the tropical Andes: Case Study Medellín - Colombia

    Science.gov (United States)

    Loaiza-Usuga, J. C.; Monsalve, G.; Arce, L.; Vahos, L. S.; Smolikova, J.; Alzate, J. A.; Ramirez-Hoyos, L.

    2016-12-01

    With the aim of understanding the dynamics of landslides in the tropical Andes of Colombia, we started a long-term project of monitoring different variables that might play a significant role in triggering mass movements. We selected an area of high slopes and active geomorphic processes in the city of Medellín - Colombia. Landslides in this area are mostly triggered by rain, and their frequency is known to be highly correlated with the bimodal distribution of rainfall that characterizes the region. After a stage of geologic and geomorphic mapping, we selected an area of active landslide processes of nearly 6 square kilometers, which is clearly affecting the nearby roads. We installed some basic equipment to measure several hydrologic variables in the soil, such as porosity, moisture, infiltration and percolation, obtaining clearly differentiated estimations for the dry and wet seasons. We also conducted several electrical resistivity tests, which included vertical soundings at specific locations along the slope, electromagnetic induction measurements to constrain lateral heterogeneity at those locations, and a resistivity tomography along the direction of maximum slope. Preliminary results suggest the presence of a layer of a debris flow about 4 m thick on top of a more consolidated material. The water table seems to fluctuate within the debris flow. The average infiltration and percolation decrease during the wet season by nearly 20% and 61% respectively. According to the measurements taken up to date, we speculate that the landslide dynamics is linked to subsurface flow in the first meters / tens of centimeters of the soil, favored by the high porosity, the presence of a fluctuating water table between 1.5 and 3 m deep, and the large contrast in electrical resistivity at a depth of 4 m.

  11. Vulnerability assessment in a participatory approach to design and implement community based adaptation to drought in the Peruvian Andes

    Science.gov (United States)

    Lasage, Ralph; Muis, Sanne; Sardella, Carolina; van Drunen, Michiel; Verburg, Peter; Aerts, Jeroen

    2015-04-01

    The livelihoods of people in the Andes are expected to be affected by climate change due to their dependence on glacier meltwater during the growing season. The observed decrease in glacier volume over the last few decades is likely to accelerate during the current century, which will affect water availability in the region. This paper presents the implementation of an approach for the participatory development of community-based adaptation measures to cope with the projected impacts of climate change, which was implemented jointly by the local community and by a team consisting of an NGO, Peruvian ministry of environment, research organisations and a private sector organisation. It bases participatory design on physical measurements, modelling and a vulnerability analysis. Vulnerability to drought is made operational for households in a catchment of the Ocoña river basin in Peru. On the basis of a household survey we explore how a vulnerability index (impacts divided by the households' perceived adaptive capacity) can be used to assess the distribution of vulnerability over households in a sub catchment. The socio-economic factors water entitlement, area of irrigated land, income and education are all significantly correlate with this vulnerability to drought. The index proved to be appropriate for communicating about vulnerability to climate change and its determining factors with different stakeholders. The water system research showed that the main source of spring water is local rainwater, and that water use efficiency in farming is low. The adaptation measures that were jointly selected by the communities and the project team aimed to increase water availability close to farmland, and increase water use efficiency, and these will help to reduce the communities vulnerability to drought.

  12. Within plate seismicity analysis in the segment between the high Cordillera and the Precordillera of northern Mendoza (Southern Central Andes

    Directory of Open Access Journals (Sweden)

    Julián Olivar

    2018-01-01

    Full Text Available Crustal seismicity in northwestern Mendoza Province in Argentina, corresponding to the transition zone between the Chilean-Pampean flat subduction zone (26.5–33.5°S and the Southern Central Andes normal subduction zone to the south, is studied in order to i identify its relationship with the mapped structure, ii determine deformational mechanisms and iii constrain the geometry of the fold and thrust belt in the lower crust. Through this, we aim to determine which are the structures that contribute to Andean construction, east of the Frontal Cordillera in Argentina and at the western Principal Cordillera in Chile. Data from a temporary local seismic network are reprocessed in order to achieve a precise location of hypocenters and, whenever possible, to build focal mechanisms. Results are interpreted and compared with previous seismic studies and structural models. Analyzed seismicity is grouped around the eastern front of Frontal Cordillera, with hypocenters mainly at depths of 25–40 km. Contrastingly, earthquakes in the Principal Cordillera to the west are located at the axial Andean sector and Chilean slope, with depths shallower than 15 km. Obtained focal mechanisms indicate mainly strike-slip displacements, left lateral at Frontal Cordillera and right lateral at Principal Cordillera. Based on these observations, new possible structural models are proposed, where seismogenic sources could be either associated with inherited basement structures from the Cuyania-Chilenia suture; or correspond to deep-blind thrusts linked with a deeper-than-previously-assumed decollement that could be shared between Frontal Cordillera and western Precordillera. This deeper decollement would coincide in turn with the one determined from receiver function analysis for the eastern Sierras Pampeanas in previous works, potentially implying a common decollement all through the fold and thrust belt configuration. Apart from this, a new interpretation of

  13. Glacier changes and climate trends derived from multiple sources in the data scarce Cordillera Vilcanota region, southern Peruvian Andes

    Science.gov (United States)

    Salzmann, N.; Huggel, C.; Rohrer, M.; Silverio, W.; Mark, B. G.; Burns, P.; Portocarrero, C.

    2013-01-01

    The role of glaciers as temporal water reservoirs is particularly pronounced in the (outer) tropics because of the very distinct wet/dry seasons. Rapid glacier retreat caused by climatic changes is thus a major concern, and decision makers demand urgently for regional/local glacier evolution trends, ice mass estimates and runoff assessments. However, in remote mountain areas, spatial and temporal data coverage is typically very scarce and this is further complicated by a high spatial and temporal variability in regions with complex topography. Here, we present an approach on how to deal with these constraints. For the Cordillera Vilcanota (southern Peruvian Andes), which is the second largest glacierized cordillera in Peru (after the Cordillera Blanca) and also comprises the Quelccaya Ice Cap, we assimilate a comprehensive multi-decadal collection of available glacier and climate data from multiple sources (satellite images, meteorological station data and climate reanalysis), and analyze them for respective changes in glacier area and volume and related trends in air temperature, precipitation and in a more general manner for specific humidity. While we found only marginal glacier changes between 1962 and 1985, there has been a massive ice loss since 1985 (about 30% of area and about 45% of volume). These high numbers corroborate studies from other glacierized cordilleras in Peru. The climate data show overall a moderate increase in air temperature, mostly weak and not significant trends for precipitation sums and probably cannot in full explain the observed substantial ice loss. Therefore, the likely increase of specific humidity in the upper troposphere, where the glaciers are located, is further discussed and we conclude that it played a major role in the observed massive ice loss of the Cordillera Vilcanota over the past decades.

  14. Glacier changes and climate trends derived from multiple sources in the data scarce Cordillera Vilcanota region, southern Peruvian Andes

    Directory of Open Access Journals (Sweden)

    N. Salzmann

    2013-01-01

    Full Text Available The role of glaciers as temporal water reservoirs is particularly pronounced in the (outer tropics because of the very distinct wet/dry seasons. Rapid glacier retreat caused by climatic changes is thus a major concern, and decision makers demand urgently for regional/local glacier evolution trends, ice mass estimates and runoff assessments. However, in remote mountain areas, spatial and temporal data coverage is typically very scarce and this is further complicated by a high spatial and temporal variability in regions with complex topography. Here, we present an approach on how to deal with these constraints. For the Cordillera Vilcanota (southern Peruvian Andes, which is the second largest glacierized cordillera in Peru (after the Cordillera Blanca and also comprises the Quelccaya Ice Cap, we assimilate a comprehensive multi-decadal collection of available glacier and climate data from multiple sources (satellite images, meteorological station data and climate reanalysis, and analyze them for respective changes in glacier area and volume and related trends in air temperature, precipitation and in a more general manner for specific humidity. While we found only marginal glacier changes between 1962 and 1985, there has been a massive ice loss since 1985 (about 30% of area and about 45% of volume. These high numbers corroborate studies from other glacierized cordilleras in Peru. The climate data show overall a moderate increase in air temperature, mostly weak and not significant trends for precipitation sums and probably cannot in full explain the observed substantial ice loss. Therefore, the likely increase of specific humidity in the upper troposphere, where the glaciers are located, is further discussed and we conclude that it played a major role in the observed massive ice loss of the Cordillera Vilcanota over the past decades.

  15. Uso de redes sociales en las revistas científicas de la Universidad de Los Andes, Venezuela

    Directory of Open Access Journals (Sweden)

    Christian Alexander Martínez-Guerrero

    2018-01-01

    Full Text Available En una sociedad donde las barreras parecen día a día más difusas, las Redes Sociales (RRSS constituyen uno los principales vehículos de comunicación directo para acceder, compartir, usar y apropiarse de contenidos que hasta hace algún tiempo implicaba mayores labores. El objetivo de este estudio fue ofrecer un diagnóstico sobre la participación en estos canales, como medios adecuados para la divulgación de conocimientos, en cada una de las 90 revistas científicas de la Universidad de Los Andes (ULA, abordado desde una metodología de trabajo de carácter documental, con diseño no experimental-transversal de tipo descriptivo, donde se determinó la presencia -y sus respectivas características- de los objetos de estudio en dos RRSS horizontales-generalistas: Facebook y Twitter, y dos verticales, de contenido y de perfiles profesionales: Youtube y LinkedIn, dadas sus capacidades de apertura y penetración en una parte importante de la población que tiene conexión a la Red. Sin embargo, se percibió que apenas el 22,3 % de las publicaciones periódicas analizadas es miembro de al menos una de estas RRSS, algunas no cuentan con constante actividad y, por tanto, la cifra de suscriptores es corta y su alcance limitado. Se recomienda al personal que allí hace vida académica procurar esfuerzos para alcanzar mejores índices de visibilidad y difusión, así como el registro en más comunidades virtuales y el trabajo constante en el mantenimiento de ellas.

  16. Quantifying Quaternary Deformation in the Eastern Cordillera of the Colombian Andes Using Cosmogenic Nuclide Geochronology and Fluvial Geomorphology

    Science.gov (United States)

    Dalman, E.; Taylor, M. H.; Veloza-fajardo, G.; Mora, A.

    2014-12-01

    Northwest South America is actively deforming through the interaction between the Nazca, South American, and Caribbean plates. Though the Colombian Andes are well studied, much uncertainty remains in the rate of Quaternary deformation along the east directed frontal thrust faults hundreds of kilometers in board from the subduction zones. The eastern foothills of the Eastern Cordillera (EC) preserve deformed landforms, allowing us to quantify incision rates. Using 10Be in-situ terrestrial cosmogenic nuclide (TCN) geochronology, we dated 2 deformed fluvial terraces in the hanging wall of the Guaicaramo thrust fault. From the 10Be concentration and terrace profile relative to local base level, we calculated incision rates. We present a reconstructed slip history of the Guaicaramo thrust fault and its Quaternary slip rate. Furthermore, to quantify the regional Quaternary deformation, we look at the fluvial response to tectonic uplift. Approximately 20 streams along the eastern foothills of the Eastern Cordillera (EC) were studied using a digital elevation model (DEM). From the DEM, longitudinal profiles were created and normalized channel steepness (Ksn) values calculated from plots of drainage area vs. slope. Knickpoints in the longitudinal profiles can record transient perturbations or differential uplift. Calculated Ksn values indicate that the EC is experiencing high rates of uplift, with the highest mean Ksn values occurring in the Cocuy region. Mean channel steepness values along strike of the foothills are related to increasing uplift rates from south to north. In contrast, we suggest that high channel steepness values in the south appear to be controlled by high rates of annual precipitation.

  17. Long-term effects of climate and land cover change on freshwater provision in the tropical Andes

    Science.gov (United States)

    Molina, A.; Vanacker, V.; Brisson, E.; Mora, D.; Balthazar, V.

    2015-06-01

    Andean headwater catchments play a pivotal role to supply fresh water for downstream water users. However, few long-term studies exist on the relative importance of climate change and direct anthropogenic perturbations on flow regimes. In this paper, we assess multi-decadal change in freshwater provision based on long time series (1974-2008) of hydrometeorological data and land cover reconstructions for a 282 km2 catchment located in the tropical Andes. Three main land cover change trajectories can be distinguished: (1) rapid decline of native vegetation in montane forest and páramo ecosystems in ~1/5 or 20% of the catchment area, (2) expansion of agricultural land by 14% of the catchment area, (3) afforestation of 12% of native páramo grasslands with exotic tree species in recent years. Given the strong temporal variability of precipitation and streamflow data related to El Niño-Southern Oscillation, we use empirical mode decomposition techniques to detrend the time series. The long-term increasing trend in rainfall is remarkably different from the observed changes in streamflow that exhibit a decreasing trend. Hence, observed changes in streamflow are not the result of long-term climate change but very likely result from direct anthropogenic disturbances after land cover change. Partial water budgets for montane cloud forest and páramo ecosystems suggest that the strongest changes in evaporative water losses are observed in páramo ecosystems, where progressive colonization and afforestation of high alpine grasslands leads to a strong increase in transpiration losses.

  18. A Quarter-Century of Glacier Recession in the Tropical Andes from Landsat: c1987 - c2013

    Science.gov (United States)

    Slayback, D. A.; Tucker, C. J.

    2014-12-01

    The glaciers of the tropical Andes constitute 99% of the world's tropical glaciers. They primarily occur in Peru and Bolivia (90%) with smaller glaciers scattered across the peaks in Ecuador, Colombia, and Venezuela. Specific glaciers in the range have been studied in great detail, such as Bolivia's Zongo glacier and Peru's Quelccaya Ice Cap, but few studies of glacier recession across the full range have been published. We previously assessed glacier recession between c1987 and c2006 using manual classification techniques on Landsat imagery. We have now updated that study to the present (2013/2014), and and have incorporated automated techniques using support vector machines. The update to present allows us to examine both the variability in recession rates, and the current state of overall recession. The primary issues in completing this analysis are accounting for snow cover (which can otherwise be easily misidentified as glacier), and developing a robust and semi-automated methodology to process the large number of individual images required. To avoid confusion with transient snow, we analysed 2-3 clear images at each epoch, with minimal visually apparent snow or glacier, and only labelled as glacier those pixels that were classified as glacier in the clear portions of each image. To automate the processing, we used support vector machines, trained with the extensive data we have available from our previous manual classification work.Our previous work indicated an overall recession of approximately 30% (or 700 km2 of glacier area loss) between c1987 and c2006. We will present updated figures from our new analysis, extending to 2013/2014.

  19. Use of high-resolution satellite images for detection of geological structures related to Central Andes geothermal field, Chile.

    Science.gov (United States)

    Benavides-Rivas, C. L.; Soto-Pinto, C. A.; Arellano-Baeza, A. A.

    2014-12-01

    Central valley and the border with Argentina in the center, and in the fault system Liquiñe-Ofqui in the South of the country. High resolution images from the LANDSAT 8 satellite have been used to delineate the geological structures related to the potential geothermal reservoirs located at the northern end of the Southern Volcanic Zone of Chile. It was done by applying the lineament extraction technique, using the ADALGEO software, developed by [Soto et al., 2013]. These structures have been compared with the distribution of main geological structures obtained in the field. It was found that the lineament density increases in the areas of the major heat flux indicating that the lineament analysis could be a power tool for the detection of faults and joint zones associated to the geothermal fields. A lineament is generally defined as a straight or slightly curved feature in the landscape visible satellite image as an aligned sequence of pixel intensity contrast compared to the background. The system features extracted from satellite images is not identical to the geological lineaments that are generally determined by ground surveys, however, generally reflects the structure of faults and fractures in the crust. A temporal sequence of eight Landsat multispectral images of Central Andes geothermal field, located in VI region de Chile, was used to study changes in the configuration of the lineaments during 2011. The presence of minerals with silicification, epidotization, and albitization, which are typical for geothrmal reservoirs, was also identified, using their spectral characteristics, and subsequently corroborated in the field. Both lineament analysis and spectral analysis gave similar location of the reservoir, which increases reliability of the results.

  20. Using terrestrial laser scanning for differential measurement of interannual rock glacier movement in the Argentine Dry Andes

    Science.gov (United States)

    Kane, Renato R.

    Argentina has recently implemented laws to protect glaciers and buried ice in the Andes to improve the sustainability of scarce, long-term water resources. Therefore, all glaciers and buried ice terrains must be located and avoided in any commercial alterations of the landscape. Buried ice in this remote and often dangerous terrain typically is located via the use of remote-sensing techniques. This thesis applies one such technique, Light Detection and Ranging (LiDAR) in the form of Terrestrial Laser Scanning (TLS), to detect rock glacier movement that is indicative of flowing, buried ice not visible in near surface excavations. TLS surveys were completed at two locales, Los Azules and El Altar, in both AD 2013 and AD 2014 on landscapes where buried ice is suspected to have produced the current surface forms. Multiple TLS scans were co-registered with the use of benchmarks, both between scans and between years, which introduced quantifiable positional errors. Digital Elevation Models (DEMs) were derived from the point cloud data by standardizing the spacing of the points in the horizontal direction, creating 0.1 m by 0.1 m cells with elevation as the cell value. The DEMs for each year were subtracted from each other to yield a change in elevation. The surface roughness of the rock glaciers (vertical variability within each cell) was empirically determined and evaluated as a threshold for results. Both sites showed sub-decimeter interannual movements, and the direction of their movement is typical of forms with buried ice. The results of the study were validated using independent GPS data showing annual movement rates. Despite the downslope movement of these rock glaciers, the volume of ice contained within them remains unclear, and further study is required to assess the volume of water contained.

  1. Initial study of arthropods succession and pig carrion decomposition in two freshwater ecosystems in the Colombian Andes.

    Science.gov (United States)

    Barrios, Maria; Wolff, Marta

    2011-10-10

    Entomological succession and trophic roles of arthropods associated with different stages of carcass decomposition were studied to estimate the post-mortem submersion interval in two freshwater ecosystems in the Colombian Andes, at an altitude of 2614 m. Pig carcasses were employed as models placed 68 m apart, one in a stream (lotic) and another in an artificial lake (lentic). Decomposition time to skeletal remains was 74 days in the lake and 80 days in the stream. Six phases of decomposition were established: submerged fresh, early floating, floating decay, bloated deterioration, floating remains and sunken remains. A total of 18,832 organisms associated with the carcasses were collected: 11,487 in the lake (four orders, 19 families and 33 species) and 7345 in the stream (eight orders, 15 families and 25 species). Organisms were classified in the following ecological categories: shredders, collectors, predators, necrophagous, sarcosaprophagous and opportunists. Physical and chemical properties of the habitats, such as water temperature, CO(2) and conductivity, varied according to rainfall. In the lake, shredders (Coleoptera: Tropisternus sp. and Berosus sp.) and collectors (Diptera: Chironomus sp.) were found to be associated with submerged phases. Predators (Odonata) were only present during the first phases. Coleoptera (Dytiscidae) were found during floating decay and bloated deterioration stages. In the stream, shredders (Hyalella sp.) and collectors (Simulium sp.) were found during all stages, whereas the predator Oxelytrum discicolle was found exclusively during the floating stages, during which body temperature increased in a fashion similar to active decay in terrestrial environments. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  2. Attenuation tomography in the western central Andes: A detailed insight into the structure of a magmatic arc

    Science.gov (United States)

    Haberland, Christian; Rietbrock, Andreas

    2001-06-01

    High-quality data from 1498 local earthquakes recorded by the PISCO '94 (Proyecto de Investigatión Sismológica de la Cordillera Occidental, 1994) and ANCORP '96 (Andean Continental Research Project, 1996) temporary seismological networks allowed the detailed determination of the three-dimensional (3-D) attenuation structure (Qp-1) beneath the recent magmatic arc in the western central Andes (20° to 24°S). Assuming a frequency-independent Qp-1 in a frequency band between 1 and 30 Hz, whole path attenuation (t*) was estimated from the amplitude spectra of the P waves using spectral ratios and a spectral inversion technique. The damped least squares inversion (tomography) of the data reveals a complex attenuation structure. Crust and mantle of the forearc and subducting slab are generally characterized by low attenuation (Qp > 1000). Crust and mantle beneath the magmatic arc show elevated attenuation. The strongest anomaly of extremely low Qp is found in the crust between 22° and 23°S beneath the recent volcanic arc (Qp < 100). N-S variations can be observed: The western flank of the crustal attenuation anomaly follows the curved course of the volcanic front. North of 21°S the attenuation is less developed. In the northern part of the study area the low-Qp zone penetrates in the forearc mantle down to the subducting slab. In the south a deeper zone of high attenuation is resolved between 23° and 24°S directly above the subducting slab. Low Qp in the mantle correlates with earthquake clusters. The strong crustal attenuation is confined to the distribution of young ignimbrites and silicic volcanism and is interpreted as a thermally weakened zone with partial melts. The attenuation pattern in the upper mantle might reflect the variable extent of the asthenosphere and maps variations of subduction-related hydration processes in the mantle wedge from slab-derived fluids.

  3. CARACTERIZACIÓN CLIMATICA DE LA ALTA CUENCA DEL RÍO NEUQUÉN, ANDES PATAGONICOS

    Directory of Open Access Journals (Sweden)

    Griselda Ostertag

    2005-12-01

    Full Text Available En el desarrollo del presente documento se analizan las principales variables meteorológicas, temperatura y precipitación, que caracterizan y definen el clima de la Cordillera de los Andes en la Patagonia, provincia de Neuquén, particularmente en el área que ocupa la alta cuenca del río Neuquén. En esta etapa, de tipo descriptiva, el análisis estadístico refleja la situación de la climatología regional en el nivel medio histórico mediante la evaluación del comportamiento de las variables mencionadas durante los últimos 25 años. En este período se han registrado eventos extremadamente húmedos como así también situaciones de sequía. El objetivo es realizar una evaluación climática a partir de la información “in situ” de estaciones meteorológicas, información satelital y análisis estadístico para definir a posteriori, en cuál clasificación climática puede encuadrarse la zona de estudio, qué tipos climáticos pueden definirse en función de la bibliografía existente al respecto, y evaluar el grado de ajuste que presentan los climas determinados con los demás componentes del paisaje tales como vegetación y suelos.

  4. Hepatitis A virus antibody

    International Nuclear Information System (INIS)

    Novak, J.; Kselikova, M.; Urbankova, J.

    1980-01-01

    A description is presented of a radioimmunoassay designed to prove the presence of the antibody against the hepatitis A virus (HA Ab, anti-Ha) using an Abbott HAVAB set. This proof as well as the proof of the antibody against the nucleus of the hepatitis B virus is based on competition between a normal antibody against hepatitis A virus and a 125 I-labelled antibody for the binding sites of a specific antigen spread all over the surface of a tiny ball; this is then indirect proof of the antibody under investigation. The method is described of reading the results from the number of impulses per 60 seconds: the higher the titre of the antibody against the hepatitis A virus in the serum examined, the lower the activity of the specimen concerned. The rate is reported of incidence of the antibody against the hepatitis A virus in a total of 68 convalescents after hepatitis A; the antibody was found in 94.1%. The immunoglobulin made from the convalescents' plasma showed the presence of antibodies in dilutions as high as 1:250 000 while the comparable ratio for normal immunoglobulin Norga was only 1:2500. Differences are discussed in the time incidence of the antibodies against the hepatitis A virus, the antibodies against the surface antigen of hepatitis B, and the antibody against the nucleus of the hepatitis V virus. (author)

  5. Ocular Tropism of Respiratory Viruses

    Science.gov (United States)

    Rota, Paul A.; Tumpey, Terrence M.

    2013-01-01

    SUMMARY Respiratory viruses (including adenovirus, influenza virus, respiratory syncytial virus, coronavirus, and rhinovirus) cause a broad spectrum of disease in humans, ranging from mild influenza-like symptoms to acute respiratory failure. While species D adenoviruses and subtype H7 influenza viruses are known to possess an ocular tropism, documented human ocular disease has been reported following infection with all principal respiratory viruses. In this review, we describe the anatomical proximity and cellular receptor distribution between ocular and respiratory tissues. All major respiratory viruses and their association with human ocular disease are discussed. Research utilizing in vitro and in vivo models to study the ability of respiratory viruses to use the eye as a portal of entry as well as a primary site of virus replication is highlighted. Identification of shared receptor-binding preferences, host responses, and laboratory modeling protocols among these viruses provides a needed bridge between clinical and laboratory studies of virus tropism. PMID:23471620

  6. Categorías conceptuales sobre la producción y gerencia del conocimiento en la Universidad de los Andes (ULA)

    OpenAIRE

    Rincón de Parra, Haydeé Cecilia; Briceño, Magally

    2008-01-01

    Esta investigación presenta como objetivo construir categorías conceptuales, a partir de lo expresado por un grupo de diez profesores-investigadores, sobre la forma en que se gerencia el proceso de producción de conocimiento en la Universidad de Los Andes. Para la recogida y análisis de los datos se consideraron algunos lineamientos de la Teoría Fundamentada. Se construyeron cinco categorías conceptuales: a) producción de conocimiento, b) filosofía del conocimiento como sustento, c) difusión ...

  7. Glacialmorphological reconstruction of glacier advances and glacial lake outburst floods at the Cachapoal glacier in the Dry Central Andes of Chile (34°S)

    Science.gov (United States)

    Iturrizaga, Lasafam; Charrier, Reynaldo

    2013-04-01

    Throughout the Andes Mountain range of South America a general trend of glacier shrinkage has taken place in the last century. Only a few glaciers have shown a rather non-continuous trend of glacier retreat and temporally advanced or even surged during the mid-19th to 20th century. One of the earliest assumed glacier surges has occurred in the upper Cachapoal catchment area at the homonymous glacier. In climatic respect the Cachapoal glacier is located in the transition zone from the most southern part of the Dry Central Andes of Chile to the more humid zone of the Wet Andes. The region is affected mainly by winter precipitation deriving from the Westerlies. The debris-covered, 12 km-long Cachapoal glacier represents one of the largest valley glaciers in the Central Andes. It is an avalanche-fed glacier with an almost 1500 m-high head wall in its upper catchment area flowing down from Picos del Barroso (5180 m) and terminates at an elevation of 2630 m a.s.l. with a bifurcated glacier tongue. A large moraine complex, almost 2 km in length and 500 m in width, separates the two glacier lobes. During times of advanced glacier tongue positions the Ríos Molina and Cachapoal may be have blocked independently at two distinct localities which are situated about 2300 m apart from each other. A blockage with temporal lake formation has occurred at least in the years 1848, 1955 and 1981 (cf. Plagemann 1887, Peña 1981), from which the rupture of the earliest glacier barrier has been the most devastating. This event is locally reminded as "la gran avenida en seco" in the historical record. Geomorphological evidence of the past historical and modern glacier expansions is given in the proglacial area by a fresh dead-ice hummocky topography and glacial trimlines at the valley flanks. More down valley broad outwash plains and boulder clusters indicate past high energy floods produced by glacier lake outbursts. Regarding the small size of the catchment area of the Río Molina

  8. Estrés académico en estudiantes de la Facultad de Farmacia y Bioanálisis, Universidad de los Andes, Mérida-Venezuela

    OpenAIRE

    Labrador Chacón, Carmen Zulay

    2012-01-01

    En esta tesis se ha tenido como objetivo, estudiar el estrés académico, así como algunos recursos psicosociales empleados, para su afrontamiento, en estudiantes de la Universidad de Los Andes, Mérida-Venezuela. La muestra estuvo constituida por 856 estudiantes del curso regular, de la Facultad de Farmacia y Bioanálisis. Para la medición del nivel de estrés académico se empleó el Cuestionario de Evaluación del Estrés Académico (CEEA) (Joan De Pablo, 2002). Para medir las variables sociodemográ...

  9. Efectos del cambio climático sobre especies de plantas vasculares del sur de los Andes Centrales: un estudio en el noroeste de Argentina (NOA)

    OpenAIRE

    Godoy Bürki, Ana Carolina

    2017-01-01

    La región de los Andes Tropicales es considerada como una región muy vulnerable al cambio climático porque presenta una alta diversidad y endemismo y porque posee una gran variabilidad altitudinal. Si bien se ha efectuado un gran número de predicciones sobre los cambios que ocurrirán en el clima, pocos estudios evaluaron el impacto que éste tendrá sobre las distribuciones de las especies. En este estudio se estima el efecto del cambio climático sobre la distribución y la conservación de espec...

  10. Pedological and mineralogical investigations on a soil-paleosoil sequence within Andosols in the Western Cordillera of the Peruvian Andes (region Laramate, 14.5S)

    Science.gov (United States)

    Leceta Gobitz, Fernando; Mächtle, Bertil; Schukraft, Gerd; Meyer, Hans-Peter; Eitel, Bernhard

    2016-04-01

    An integrated research project of environmental sciences focuses on a group of four Andosol profiles in Western flank of the Peruvian southern Andes. Aim of this study is to contribute to the reconstruction of the paleo environmental conditions in the Western Cordillera of the Peruvian Andes. Standard pedological and sedimentological analysis has been conducted in order to identify morphological and geochemical features generated by climatic variations during the middle and late Holocene. Though a provenance analysis of sediments, all potential lithological sources around the town of Laramate are being examined under the scanning electron microscope, in order to find significant mineralogical associations downward the soil-profile. Preliminary results reveal two edaphic cycles within a soil-paleo soil-sequence: a relative poor developed "Ah" topsoil, mostly composed by fine grain sediments, is underlain by a well preserved "2Ah" paleo soil; a "2Bwt" subsoil exhibits signs of alteration and clay translocation; parent material in slight weathered statement at "2C" culminates the sequence. Mineralogical analytical data supports the premise, that materials in the uppermost horizons are relatable to distal geological units of the Western and Eastern Cordillera, therefore also related to other described aeolian archives from the region: "Desert Margin Loess" at the Andean foot-zone and "Mixed Loess" in the Puna grassland. The amphibole varieties Actinolite, Mg-Hornblende and Edenite could be only distinguished within the soil sediments. The fluvial transport to its current position is excluded, insofar mentioned varieties stem from the granodiorites of Coastal Batholite (downstream the study area), and the vulcanites of the Anta und Andahuaylas Formation (eastward the continental divide). References: Eitel, B., et al. (2005). "Geoarchaeological evidence from desert loess in the Nazca-Palpa region, southern Peru : Palaeoenvironmental changes and their impact on Pre

  11. El tarwi o chocho: una de las principales fuentes de proteína vegetal de las comunidades indígenas de los Andes Centrales

    OpenAIRE

    Planchuelo, Ana M.; Fuentes, Esteban P.

    2005-01-01

    El lupino andino (Lupinus mutabilis Sweet) conocido también como tarwi o chocho, es una especie de leguminosa nativa de los Andes Centrales. Su domesticación se remonta a los principios de la cultura Nazca y desde ese entonces hasta la actualidad el cultivo está ampliamente difundido en las laderas montañosas y en los altos valles de Ecuador, Perú y Bolivia. La importancia del lupino para las comunidades andinas prehispánicas quedo documentada en pinturas de cerámicas y en tributos encontrado...

  12. VHS virus - present situation

    DEFF Research Database (Denmark)

    Skall, Helle Frank; Olesen, Niels Jørgen

    2015-01-01

    of the worldwide distribution of the disease will be given. Virus evolution: Recent studies indicate that only a few amino acid changes in the structural proteins of VHSV can change the virulence patterns significantly, thereby coming closer to assessing the risk of none to low virulent viruses becoming high...... virulent. Virulence factors both depend on the ability of VHSV to enter a cell and on the speed and efficiencyof virus replication in the cells. Apparently the viral nucleocapsid protein plays a very important role for the later and seems to be the target for determination of a virulence marker....

  13. Zika virus in Asia

    Directory of Open Access Journals (Sweden)

    Veasna Duong

    2017-01-01

    Full Text Available Zika virus (ZIKV is an emerging mosquito-borne virus that was first isolated from a sentinel rhesus monkey in the Zika Forest in Uganda in 1947. In Asia, the virus was isolated in Malaysia from Aedes aegypti mosquitoes in 1966, and the first human infections were reported in 1977 in Central Java, Indonesia. In this review, all reported cases of ZIKV infection in Asia as of September 1, 2016 are summarized and some of the hypotheses that could currently explain the apparently low incidence of Zika cases in Asia are explored.

  14. Zika virus in Asia

    OpenAIRE

    Veasna Duong; Philippe Dussart; Philippe Buchy

    2017-01-01

    Zika virus (ZIKV) is an emerging mosquito-borne virus that was first isolated from a sentine