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Sample records for central south chile

  1. Reduction of firewood consumption by households in south-central Chile associated with energy efficiency programs

    International Nuclear Information System (INIS)

    Cities in the central-southern area of Chile face serious environmental pollution due to extensive use of firewood for heating. Low energy efficiency of constructions and cold climate increase the problem, which also affects native forests. The aims of this study are to characterize energy consumption in dwellings of this region, investigate the reduction potential, and study social and environmental consequences of high consumption of firewood. Actual energy consumption is studied with information from surveys, potential for reduction is modeled with software and other consequences are analyzed from previous studies. Results for the city of Valdivia show high firewood consumption per household, with a media bulk volume near 12 m3/year. Thermal regulations are softer compared with other countries. Moreover, around 85% of buildings were built before enforcing codes in 2007, and has almost no thermal protection. The reduction potential due to thermal improvements is found to be very high (62%) if buildings are refurbished to comply with the present Chilean Norm of 2007, but it reaches a 77% reduction if refurbished according to stricter foreign regulations. Therefore, an energy efficiency program strongly addressing existing buildings has the largest potential for reducing firewood use, and therefore mitigate environmental and health impacts. - Highlights: • High firewood consumption and environmental pollution in cities of south-central Chile. • High use of firewood due to inefficient constructions and soft thermal regulations. • Potential reduction of energy consumption up to 77% with more demanding regulations. • Policies should address building stock before thermal regulation, corresponding to 85%

  2. Proposals to enhance thermal efficiency programs and air pollution control in south-central Chile

    International Nuclear Information System (INIS)

    Major cities in South-central Chile suffer high levels of particulate matter PM10 and PM2.5 due to combustion of solid fuels for heating. Exposure to these air pollutants is recognized as a major contribution to ill health in the region. Here we discuss new strategies to reduce air pollution. Regulations and subsidies focusing on improved combustion by providing drier wood fuel and better stoves have been in effect since 2007. However, air pollution due to combustion of wood fuel has been steadily rising, along with reports on health consequences. The paper analyzes a survey of 2025 households in the city of Valdivia, which found that wood fuel quality, stove renewal, and awareness of programs are strongly affected by income level, and that higher consumption of wood fuel is found in households already having better stoves and drier wood fuel. The analysis suggests that regulations intended to improve combustion are influenced by user's behavior and have limited potential for lowering pollution. We conclude that thermal refurbishment has a larger potential for improvement, not yet been implemented as an energy policy for the majority. Here we propose improvements and additions to current programs to enhance effectiveness and cover the whole social spectrum. - Highlights: • High levels of PM2.5 from wood combustion affect cities of south-central Chile. • Current programs on dry wood fuel and stoves renewal have not reduced air pollution. • Real operation of wood stoves strongly depends on user's behavior. • Buildings' energy efficiency has greater potential for reducing emissions. • Retrofit prevents degradation of native forest and improves indoor temperature

  3. Comparative Study Of Focal Mechanisms In South Central Chile Before And After The 2010 Maule Earthquake

    Science.gov (United States)

    Agurto, H.; Rietbrock, A.; Ryder, I. M.; Haberland, C. A.

    2011-12-01

    On 27 February 2010, a Mw=8.8 earthquake occurred off the coast of south central Chile rupturing nearly 500 km of the subduction zone plate interface. The earthquake also generated a tsunami and caused more than 500 fatalities. The largest earthquakes recorded have taken place along subduction margins (e.g. Chile 1960, 2010, Andaman-Sumatra 2004, Japan 2011) and understanding their rupture mechanisms and deformation regimes is therefore of vital importance. From November 2004 to October 2005, the TIPTEQ project ("From The Incoming Plate to megaThrust EarthQuake"; Rietbrock et al., 2007; Haberland et al., 2009) maintained a network of 120 seismic stations inland and 10 stations at sea between 37 and 39° lat. S., continuously-recording and monitoring the seismicity occurring in the area before the 2010 Maule earthquake. By using first motion polarities and moment tensor inversion we have computed and analyzed focal mechanisms for a subset of data from these records. We found thrust faulting along the subduction interface down to a depth of ~30 km, followed by a gap in the seismicity and then deeper earthquakes showing diverse faulting mechanisms more sparsely distributed within the subducting plate. We also see strike-slip crustal faulting occurring down to ~12 km depth within the area of the Lanalhue fault. The most striking observation is the presence of deep (40 km) normal faulting seismicity in the fore-arc, close to the trench. We have now started to analyze the International Maule Aftershocks Dataset (IMAD) of the 2010 earthquake in the southern rupture region. Again we observe thrust faulting in the subduction interface and a seismic gap between an upper and lower zone of seismicity along the interface. By comparison of the pre- and post-earthquake datasets we are investigating whether the Maule earthquake caused any changes in the style of deformation in this part of Chile. References Haberland, C., A. Rietbrock, D. Lange, K. Bataille, and T. Dahm (2009

  4. Late Pleistocene to Holocene tephrostratigraphy of the Lonquimay Volcano, South Central Chile

    Science.gov (United States)

    Gilbert, D.; Freundt, A.; Kutterolf, S.; Burkert, C.

    2010-12-01

    The Lonquimay Volcanic Complex (LVC) in South Central Chile (38.38°S, 71.58°W) is part of the Southern Volcanic Zone of the Andes, which formed in response to the subduction of the Nazca Plate beneath the South American Plate. During the course of its magmatic evolution, the LVC produced explosive eruptions documented in the succession of widespread tephra deposits, as well as large lava flows that originated from the main edifice and several adjacent minor eruptive centers. The last eruptive phase in Lonquimays volcanic evolution occurred from 1988-1990. It led to the formation of the Navidad cinder cone with its associated 10.2 km long lava flow, and a widely distributed tephra blanket of andesitic composition (Moreno and Gardeweg, 1989). During recent field work we reinvestigated and complemented the LVC tephrostratigraphy as originally established by Polanco (1998)by detailed logging of 22 outcrops and collecting 126 stratigraphically controlled samples that were analyzed for their matrix glass, mineral and bulk rock compositions. This data set allows us to verify and extend the field-based correlations, and to establish a tephrostratigraphy for the LVC that comprises 15 stratigraphic units (LQA-LQO) and provides a framework for ongoing investigations of the petrogenetic evolution of the LVC. The stratigraphic record identifies at least 13 explosive eruptions of VEI > 3 that occurred since the last glaciation period (17150 a BP, McCulloch et al. 2000). Magmatic compositions of the tephra deposits range from basaltic scoriae (51wt% SiO2) to evolved dacitic pumice lapilli layers (67wt% SiO2), and thus have a wider compositional range than the chemically distinct andesitic lavas (57-63wt%) of the LVC. The vertical succession of tephra compositions reflects four periods of progressive magmatic differentiation, each successively tapped by several eruptions. The maximum degree of fractionation reached during these periods increases to younger ages. The

  5. Application of the 137Cs technique to quantify soil redistribution rates in paleohumults from Central-South Chile

    International Nuclear Information System (INIS)

    The objective of the present study was to evaluate the applicability of the 137Cs technique in obtaining spatial distributed information on mean soil redistribution rates in Central-South Chile. For this purpose four fields of Palehumult soil and contrasting land use and management were selected in the Coastal Mountain Range of the 9th Region: Crop fields under subsistence and commercial management and non-permanent prairies under subsistence and commercial management. The spatial distribution of the soil redistribution rates obtained by the 137Cs method was similar to the one obtained by pedological observations. Also, annual sediment fluxes measured at experimental plots were similar to the erosion rates determined by the 137Cs method at adjacent points. The 137Cs technique is seen as an efficient method to obtain long-term soil redistribution rates under the climatic conditions and the soil type selected in Chile. In the future, it is necessary to study the applicability of the method under other climatic conditions and soil types occurring in Chile in which erosion is not so evident, and to adjust the method to optimise costs and benefits. (author)

  6. Modelling the day to day wind variability offshore central Chile at about 30 deg. south

    International Nuclear Information System (INIS)

    Cycles of strengthening and relaxation of the winds offshore 30 degrees S at central Chile, are related to the propagation of coastal-lows, a year-round phenomenon occurring with periodicities of about one in five days. Simple physical modelling of the day to day variability of the alongshore wind component at a coastal strip extending offshore up to the Rossby deformation radius of these wave perturbations, is presented in terms of the relevant horizontal pressure gradients and the ageostrophic components arising from the coastal-low propagation. The results of 5-day composites of 8 wind-events each, at the winter and summer halves of the annual cycle, respectively; lead to a good agreement between the observed phase-lag of the winds with respect to the pressure forcing field, stressing the importance of the ageostrophic wind components at the extremes of the pressure wave perturbation associated with the passage of coastal-lows over the Point Lengua de Vaca (30 15 S) area. A possible contribution of the upwelling-favorable wind enhancement at the time of the pressure rise and subsequent fall, ahead of the coastal-low, is postulated through an upwelling-front low-level jet, that would be carried onshore and closer to the surface by the combination of the enhanced coastal upwelling, the coastal depression of the subsidence inversion base and the coastal ageostrophic wind components during the passage of the leading edge of the coastal lows. (author). 26 refs, 5 figs, 1 tab

  7. Multiproxy approach revealing climate and cultural changes during the last 26kyrs in south-central Chile

    Science.gov (United States)

    Abarzua, Ana M.; Jarpa, Leonora; Martel, Alejandra; Vega, Rodrigo; Pino, Mario

    2010-05-01

    Multiproxy approach from Purén Lumaco Valley (38°S) describes the paleonvironmental history during the Last Maximum Glacial (LGM) in south-central Chile. Three sediment cores and severals AMS 14C dates were used to perform a complete pollen, diatoms, chironomids, and sedimentological records demonstrating the existence of a large and non profundal paleolake, between 25 and 20kyr BP. Some of these evidence are laminated silty-clay sediments (lacustrine rhythmites), associated with the presence of siderite mineral (FeCO3), besides biological proxies like Fragilaria construens and Stauroforma inermes (planctonic diatoms), and Dicrotendipes sp. and Tanytarsini tribe (littoral chironomids). The pollen ensemble reveals the first glacial refuge of Araucaria araucana forests in the low lands during the LGM. The lake was drained abruptly into a swamp/bog at 12kyr BP and colonized by Myrtaceae wet forest. This evidence suggest the dry/warm climate period of early Holocene in south-central Chile. Later, the sediments indicate variable lacustrine levels, and increase of charcoal particles, associated to current climatic conditions. The pollen spectrum dominated by Myrtaceae and Nothofagus contrasts with a strongly disturb current landscape. Actually, Purén-Lumaco valley constitutes a complex peat-bog system dominated by exotic grasses and forest species (Tritricum aestivum, Pinus radiata and Eucalyptus spp.). Some archaeological antecedents in the area document the human development at ca. 7yrs BP. The greatest archaeological characteristic present in the valley is the kuel, a Mapuche earth accumulation. The presence and extension of almost 300 kuel in the valley reflect the social/economic development, and partly explains why the region was the major resistance area for Spanish colonizer during XVI-XVII centuries. Also the archaeological findings reveal the presence of maize pollen (Zea mays) within their food consumption. The influence of climate and human impact in

  8. The relation of the mid-Tertiary coastal magmatic belt in south-central Chile to the late Oligocene increase in plate convergence rate

    OpenAIRE

    Jorge Muñoz; Rosa Troncoso; Paul Duhart; Pedro Crignola; Lang Farmer; Charles R. Stern

    2000-01-01

    The mid-Tertiary Coastal Magmatic Belt in south-central Chile, which crops out both in the Central Valley and, south of 41°S, in the Coastal Cordillera as far west as the Pacific coast, formed when the locus of Andean magmatic activity expanded, both to the west and to the east relative to its previous and current location in the Main Cordillera. This expansion of the magmatic arc occurred in conjunction with a regionally widespread episode of late Oligocene to Miocene extension which thinned...

  9. Heterogeneity of farms entering export supply chains: the case of fruit growers from central-south Chile

    Directory of Open Access Journals (Sweden)

    J. A. Barrena Ruiz

    2013-03-01

    Full Text Available The increasing stringency of world food markets requires farmers to adjust farm structure and commercial strategies to remain integrated in export supply chains. The goal of this study was to identify and characterize different types of fresh fruit farms with regard to farm structural and commercial strategies for a representative sample of fresh fruit growers from central-south Chile exporting to world markets. A typology of farms was constructed based on multivariate analysis, according to which five types of farms were differentiated from five distinct factors. Cluster I comprised the smallest and uncertified farms (14.3% of the sample. The remaining four clusters comprised certified farms, but with different farm structural and commercial characteristics. Cluster II (15.1% was composed of farms located further from market connections. Cluster III (23.9% comprised farms with the highest number of fruit species, and consequently, more diversified in fruit production. Cluster IV (8.8% was the smallest group, and comprised the largest firms. Finally, Cluster V (37.8% was composed of highly specialized fruit farms, with the highest proportion of hectares dedicated to the production of a single fruit species. The results show the heterogeneity among fresh fruit farms and support the need for differentiated incentives and technological transfer schemes from the public sector and fruit companies in order to successfully keep farmers within export supply chains.

  10. Adaptation to climate changes on a multipurpose hydrosystem in South-Central Chile with explicit regard of model uncertainty

    Science.gov (United States)

    Ayala; McPhee, J. P.

    2010-12-01

    Decision-making in the agricultural and hydropower sectors can benefit from water resources availability projections that take into account uncertainty in a meaningful way. In this work we use statistically downscaled projections of 12 general circulation models under 3 emissions scenarios to drive a hydrologic-operational model of the upper Laja river basin in south-central Chile. The Laja hydrosystem is characterized by a large natural reservoir of 5600 Hm3 that is used for agricultural purposes in the lower basin and as the cornerstone of hydroelectric supply for the entire central Chilean electric system. The upper Laja river basin is snowmelt driven so water resources are very sensitive to both precipitation and temperature. Using each future projected series as an independent observation, empirical probability distributions are calculated for hydro-meteorological and operational variables such as reservoir levels and energy production. By the end of the 21st century, the mean value of projections shows a temperature increase of 2C, a precipitation decrease of 20%, and a decrease close to 25% in runoff due to evapotranspiration effects. A runoff-precipitation-temperature relation shows that the evaporation is most important in wet conditions because of the higher levels of water availability on surface and superior layers of soil. Operational results show a decrease of reservoir levels coupled with diminishing energy output, which suggests that the current operational policy is inappropriate for ensuring adaptation to climate change. Differences among GCMs clearly increase trough the analysis period resulting in a greater uncertainty in the magnitude of changes by the end of the 21st century. Almost all models and scenarios agree about the general trends of the estimated variables. Nevertheless, for climate change applications, the considerable magnitude differences between projections suggest the use of many models instead of a particular one or, in lieu if

  11. Pyruvate Oxidoreductases Involved in Glycolytic Anaerobic Metabolism of Polychaetes from the Continental Shelf off Central-South Chile

    Science.gov (United States)

    González, R. R.; Quiñones, R. A.

    2000-10-01

    The presence of low oxygen conditions in extensive areas of the continental shelf off central-south Chile has important effects on the biochemical adaptations of the organisms living in this ecosystem. Polychaetes assemblages cohabit on the shelf with an extensively distributed prokaryotic community made up of giant filamentous sulfur bacteria (mainly Thioploca sp.). The aim of this research was to characterize the pyruvate oxidoreductases enzymes involved in the biochemical adaptation of these benthic polychaetes. Nine polychaete species ( Paraprionospio pinnata, Nephtys ferruginea, Glycera americana, Haploscoloplos sp., Lumbrineris composita, Sigambra bassi, Aricidea pigmentata , Cossura chilensis, and Pectinaria chilensis) were assayed for lactic dehydrogenase (LDH), octopine dehydrogenase (OPDH), strombine dehydrogenase (STRDH) and alanopine dehydrogenase (ALPDH). Each species had a characteristic number of the pyruvate oxidoreductases assayed ranging from 4 in Paraprionospio pinnata to 1 in Pectinaria chilensis . The pyruvate saturation curves obtained for the enzymes from all species analysed, except L. composita, suggest that NADH can be oxidized at different rates depending on the amino acid used in the reaction with pyruvate. Our results indicate that organisms having more that one pyruvate oxidoreductase present a greater metabolic capacity to cope with functional and environmental hypoxia because these enzymes would better regulate the pyruvate consumption rate during the transition period. Thus, the dominance of Paraprionospio pinnata in the study area and its worldwide distribution is consistent with its higher number of pyruvate oxidoreductases with different pyruvate consumption rates involved in anaerobic metabolism. Finally, a positive allometric relationship was found between body size and the specific activity of ALPDH, STRDH, and maximum pyruvate oxidoreductase specific activity. This latter result suggests a positive scaling of the specific

  12. Adaptation and Genotype x Environment Interaction of Flaxseed (Linum usitatissimum L. Genotypes in South Central Chile Adaptación e Interacción Genotipo x Ambiente en Lino (Linum usitatissimum L. en la Zona Centro Sur de Chile

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    Marisol Berti

    2010-09-01

    Full Text Available Flaxseed (Linum usitatissimum L. is imported into Chile mostly for bread making and feed. Identification of genotypes best adapted for seed production in South Central Chile would facilitate producer’s decision. The objective of this study was to determine the adaptation and genotype x environment interaction of 16 flaxseed genotypes (including 10 from North American and six from Argentine sources grown at 11 environments (defined as location-year in Chile from 2003 to 2007. Genotype seed yield was above 5700 kg ha-1 for some environments indicating a high yield potential. According to the AMMI (Additive Main Effects and Multiplicative Interaction and SREG (Sites regression models the 11 environments were classified into four groups by the AMMI and three groups by the SREG models. Genotypes were classified into five groups by the SREG model with four of the groups as single genotypes. Overall mean seed yield was similar for all genotypes; however the genotype Nekoma was the most stable and higher yielding genotype across environments. The environment with the highest yield potential was Chillán 2003-2004, but this location had low yield stability across years. The environments with greatest seed yield potential, Chillán 2003-2004 and Los Ángeles 2004-2005, had irrigation during flowering and seed filling. Seed oil content fluctuated between 420 and 530 g kg-1. The climatic differences among environments did not influence oil composition as expected from previous research. Flaxseed appears adapted to South Central Chile with differences observed among genotypes for biomass and seed yield, harvest index, test weight, oil content, and composition.La semilla de lino (Linum usitatissimum L. se importa a Chile principalmente para panaderías y alimento animal. La identificación de genotipos altamente productivos en la zona Centro Sur de Chile facilitaría la decisión de los productores. El objetivo de este estudio fue determinar la adaptaci

  13. Fallout radionuclides 137Cs and 7Be as an important tool to evaluate effectiveness of no-tillage systems in Central-South Chile

    International Nuclear Information System (INIS)

    Since 1970 the process of agricultural intensification has drastically increased soil erosion and associated soil degradation in the coastal mountains of south-central Chile. Due to conventional tillage (with burning of crop residues), over 80% of the soils under agriculture show evidence of compaction below plough depth and erosion rates are described amongst the highest for any agricultural land in Chile. The current study developed a simplified method for using 137Cs depth distribution datasets to estimate soil loss or accumulation at a sampling point under conventional tillage and after the shift to a no-till system. Previous applications of 137Cs measurements had been limited to the estimation of erosion rates during the period extending from the beginning of fallout receipt to the time of sampling. The new procedure allows the change in erosion rates associated with a shift in land tillage practices to be estimated. It represents an innovative application of 137Cs measurements in soil erosion research. In an additional study to assess no-till systems with and without burning of crop residues after harvesting, 7Be was used to quantify the erosion that occurred within the same field area, as a result of burning and a period of extreme rainfall (400 mm in 27 days, May 2005)

  14. K-Ar geochronologic evidence for a triassic metamorphic event in the main Chiloe Island, south-central Chile

    International Nuclear Information System (INIS)

    Pioneers geological reconnaissance studies in the Chiloe Archipelago recognised a Palaeozoic metamorphic basement (Saliot, 1969; Watters and Fleming, 1972; Valenzuela, 1982; Valdivia, 1986). Currently in progress geologic studies (Munoz et al., 1999, Duhart et al., 2000; Antinao et al., 2000) interpreted these rocks as part of the Bahia Mansa Metamorphic Complex (Duhart et al., 2000), well exposed to the north and equivalent to the 'Serie Occidental' (Aguirre et al., 1972). Geochronologic data set indicate that this complex evolved during Devonian to Triassic times. In the main Chiloe Island, this metamorphic complex is mainly conform by metasedimentary and metavolcanic rocks covered by Tertiary sedimentary and volcanic rocks and Quaternary glacial, fluvial, estuarine, beach, eolian and fluvial deposits. According to north-west and north-south lineament observed in satellite images, regional magnetic maps and topographic features, the main Chiloe island have been divide in northern, central and southern segments (Munoz et al., 1999). These lineaments are interpreted as regional faults but their ages and cinematic are not well constrained. The central segment was interpreted as an uplifted tectonic block and recent studies in the northern part of this segment have identified an intrusive body herein named as 'Metalqui Pluton'. Although the age of this pluton is unknown yet, Cretaceous intrusive rocks in the same tectonic setting of the Metalqui Pluton have been reported in the Valdivia area (Munizaga et al., 1988; Duhart et al., 1998). Previous U-Pb radiometric ages for detrital zircons from pelitic schists in the northern segment indicated a maximum sediment deposition age during Early to Middle Devonian (Duhart et al., 1999). Also, Triassic K-Ar and 40Ar/39Ar ages have been determined for the main metamorphic and tectonic event. This contribution report Triassic K-Ar ages for the central segment and discuss their regional significance (au)

  15. Long-term responses of sandy beach crustaceans to the effects of coastal armouring after the 2010 Maule earthquake in South Central Chile

    Science.gov (United States)

    Rodil, Iván F.; Jaramillo, Eduardo; Acuña, Emilio; Manzano, Mario; Velasquez, Carlos

    2016-02-01

    Earthquakes and tsunamis are large physical disturbances frequently striking the coast of Chile with dramatic effects on intertidal habitats. Armouring structures built as societal responses to beach erosion and shoreline retreat are also responsible of coastal squeeze and habitat loss. The ecological implications of interactions between coastal armouring and earthquakes have recently started to be studied for beach ecosystems. How long interactive impacts persist is still unclear because monitoring after disturbance generally extends for a few months. During five years after the Maule earthquake (South Central Chile, February 27th 2010) we monitored the variability in population abundances of the most common crustacean inhabitants of different beach zones (i.e. upper, medium, and lower intertidal) at two armoured (one concrete seawall and one rocky revetment) and one unarmoured sites along the sandy beach of Llico. Beach morphology changed after the earthquake-mediated uplift, restoring upper- and mid-shore armoured levels that were rapidly colonized by typical crustacean species. However, post-earthquake increasing human activities affected the colonization process of sandy beach crustaceans in front of the seawall. Lower-shore crab Emerita analoga was the less affected by armouring structures, and it was the only crustacean species present at the three sites before and after the earthquake. This study shows that field sampling carried out promptly after major disturbances, and monitoring of the affected sites long after the disturbance is gone are effective approaches to increase the knowledge on the interactive effects of large-scale natural phenomena and artificial defences on beach ecology.

  16. Sedimentology, paleontology and age of the Ayacara and Lago Ranco formations (south-central Chile, 40°- 42°S). Tectonic implications.

    Science.gov (United States)

    Encinas, Alfonso; Zambrano, Patricio; Bernabe, Pablo; Finger, Kenneth; Buatois, Luis; Duhart, Paul; Valencia, Victor; Fanning, M.; Herve, Francisco

    2010-05-01

    Deep-marine, Mio-Pliocene strata correlative with the Navidad Formation crop out in different areas along the forearc of south-central Chile (~34°-41°) and have also been recognized in boreholes drilles on the continental shelf. However, at Lago Ranco (40°S) and Ayacara (42°) there are outcrops of marine strata whose age and correlation with these units remain uncertain. These deposits consist of rhythmic successions of sandstone and siltstone representing facies similar to those of the Navidad and correlative formations. These marine successions are known ase the Estratos de Lago Ranco and Ayacara formations. They both crop out in the western Andean Cordillera near the limit with the Intermediate Depression at Lago Ranco and the submerged equivalent of this physiographic unit at Ayacara. There are very few studies carried out on these units and most of them consist on internal reports and unpublished theses.In order to unravel the sedimentary enviroment, age and tectonic history of this area during the Neogene we carried out sedimentological, ichnological and micropaleontological studies. In addition, we carried out U-Pb dating in detrital zircons (LAICPMS and SHRIMP). Our studies show the presence of sedimentary features and ichnofacies typical of deposition in a deep-marine environment for these units..In agreement, benthic foraminifers (Ciclamina incisa and Siphonodosaria sangrinensis) indicate lower bathial depths (1500 m). U-Pb (LAICPMS and SHRIMP) indicate a maximum depositional age of around 20 Ma for these units. In agreement, the occurrence of the planktic foraminifer species Globorotalia siakensis (P22-N14), Globigerinoides quadrilobatus (N6-Recent) and Globigerinoides sikanus (N8-N9) in strata of the Ayacara Formation suggest an early-middle Miocene age for this unit. These data indicate that the area corresponding to the western Main Andean Cordillera in south central Chile, was subjeted to major subsidence during the early-middle Miocene. Major

  17. The Genus Austroleptis from South Chile and Patagonia (Diptera, Rhagionidae)

    OpenAIRE

    NAGATOMI, Akira; NAGATOMI, Hisako; ナガトミ, アキラ; ナガトミ, ヒサコ; 永冨, 昭; 永冨, 尚子

    1988-01-01

    The genus Austroleptis from South Chile and Patagonia is revised and three new species are added. So, there are eight known species, five of which are from South Chile and Patagonia and three from Australia and Tasmania.

  18. Use of 137Cs to estimate tillage- and water-induced soil redistribution rates on agricultural land under different use and management in central-south Chile

    International Nuclear Information System (INIS)

    The purpose of this research was to evaluate the applicability of conventional 137Cs sampling and a simplified approach, for estimating medium-term tillage- and water-induced soil erosion and sedimentation rates on agricultural land in Chile. For this purpose, four study sites under contrasting land use and management were selected in central-south Chile. First, a conventional 137Cs approach, based on grid sampling was applied, adapting a mass balance conversion model incorporating soil movement by tillage to the site specific conditions of the study region. Secondly, using the same conversion model, the feasibility of estimating soil redistribution rates from measurements of 137Cs inventories based on composite soil samples taken along contour lines was also tested at all four sites. The redistribution rates associated with tillage and water and the total rates estimated using both methods correlated strongly at all four sites. The conventional method provides more detailed information concerning the redistribution processes operating over the landscape. The simplified method is suitable for assessing soil loss and sediment accumulation in areas exhibiting simple topography and almost similar slopes along the contour lines. Under these conditions, this method permits faster estimation of soil redistribution rates, providing the possibility of estimating soil redistribution rates over larger areas in a shorter time. In order to optimise the costs and benefits of the methods, the sampling and inventory quantification strategy must be selected according to the resolution of the required information, and the scale and complexity of the landscape relief. Higher tillage- and water-induced erosion rates were observed in the annually ploughed cropland sites than in the semi-permanent grassland sites. Subsistence managed crop and grassland sites also show greater erosion effects than the commercially managed sites. The 137Cs methods used permit discrimination between

  19. The relation of the mid-Tertiary coastal magmatic belt in south-central Chile to the late Oligocene increase in plate convergence rate

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    Jorge Muñoz

    2000-12-01

    Full Text Available The mid-Tertiary Coastal Magmatic Belt in south-central Chile, which crops out both in the Central Valley and, south of 41°S, in the Coastal Cordillera as far west as the Pacific coast, formed when the locus of Andean magmatic activity expanded, both to the west and to the east relative to its previous and current location in the Main Cordillera. This expansion of the magmatic arc occurred in conjunction with a regionally widespread episode of late Oligocene to Miocene extension which thinned the crust below the proto-Central Valley in south-central Chile and generated sedimentary basins west of, within, and east of the Main Cordillera. The extrusive rocks of the mid-Tertiary Coastal Magmatic Belt are interbedded with the late Oligocene to Miocene continental and marine sediments deposited in these basins, and forty-seven of the fifty new and previously published age determinations for these rocks are within the time period 29 Ma (late Oligocene to 18.8 Ma (early Miocene. The initiation of extension, basin formation and the westward migration of magmatic activity coincides closely to the beginning, in the late Oligocene, of the current period of both high convergence rate (>10 cm/yr and less oblique convergence, which together resulted in an approximately three-fold increase in trench-normal convergence rate between the Nazca and South American plates. Extension continued, along with a transient steepening of subduction angle as indicated by the westward migration of the volcanic front during the formation of the mid-Tertiary Coastal Magmatic Belt, during an approximately 10 million year period after the trench-normal convergence rate tripled across the Nazca and South American plate boundary. The mid-Tertiary Coastal Magmatic Belt includes igneous rocks chemically similar to modern Andean arc magmas, as well as rocks with ocean island basalt chemical affinities characterised by lower Ba/La (+5. The latter formed by melting of mantle

  20. Synchronous degassing patterns of the neighbouring volcanoes Llaima and Villarrica in south-central Chile: the influence of tidal forces

    Science.gov (United States)

    Bredemeyer, Stefan; Hansteen, Thor H.

    2014-10-01

    The neighbouring volcanoes Villarrica and Llaima are two of the most active volcanoes in Chile and both currently degas continuously. We present a semi-continuous time series of SO2 fluxes for Villarrica and Llaima volcanoes. The time series was obtained using five scanning Mini-Differential Optical Absorption Spectrometers (Mini-DOAS, UV spectrometers) over 6 months (13 February to 31 July 2010) and is based on 6,829 scans for Villarrica and 7,165 scans for Llaima. Statistical analyses of the SO2 flux time series reveal a periodicity of degassing maxima about every 7 days, and further a conspicuous synchronicity of the degassing maxima and minima between the two volcanoes. Intra-day variations in SO2 fluxes also show a striking correlation between Villarrica and Llaima. All these patterns correlate well with the trend of the modelled solid Earth tide curves, where the 7-day degassing maxima correspond with both the fortnightly tidal maxima and minima. The intra-day degassing peaks mostly correlate well with the periods of maximum deformation rates during the diurnal tidal cycle, and further with semidiurnal minima in atmospheric pressure, a phenomenon we refer to as "the tidal pump". As there is little time lag between the tidal action and the changes in degassing rates, we infer that degassing at both volcanoes is controlled by conduit convection, involving physical separation between gas and magma at comparatively shallow levels. Variations in daily degassing rates were up to a factor of ca. 12 and 10 for Villarrica and Llaima, respectively, without any noticeable changes in the periodicity. We thus suggest that the described cyclic variations must be taken into account for all comparable volcanoes when using gas monitoring as a tool for volcanic hazard mitigation.

  1. A new record of Equus (Mammalia: Equidae from the Late Pleistocene of central-south Chile Un nuevo registro de Equus (Mammalia: Equidae para el Pleistoceno Superior de Osorno, Chile

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    OMAR P RECABARREN

    2011-12-01

    Full Text Available Fourteen dental and bone parts of a horse excavated from the Pilauco paleontological site, Osorno (40°39' S-73°07' W are analysed and interpreted. This site was formed in association with a peat bog located on the banks of the old Damas River and has conserved abundant late Pleistocene mammalian fauna and flora materials. A date of 11457 ± 140 14C yrs B.P. was obtained from a molar and agrees with our stratigraphic age model. We have identified the fossils as pertaining to the species Equus (Amerhippus andium, which confirms its presence in central-south Chile. Furthermore, the recorded geographic location indicate that the metapodial adaptations of the specimens previously described agree with the reconstructed late Pleistocene landscape of Pilauco, dominated by soft volcanic soils and isolated forest patches over large extensions of grasslands.Se analizan e interpretan 14 fósiles correspondientes a dientes y huesos de caballo registrados en el sitio Pilauco, Osorno (40°39' S-73°07' W. El sitio se formó asociado a un pantano en un borde del antiguo río Damas; en él se ha conservado abundante material de mastofauna y flora pleistocénica. Una fecha radiocarbónica de 11457 ± 140 A.P obtenida de un molar, es concordante con el modelo de edad del sitio. La identificación taxonómica permite asociar a los fósiles a la especie Equus (Amerhippus andium, lo que confirma la presencia de la especie en el centro-sur de Chile. Por otra parte, la posición geográfica de los hallazgos y la reconstrucción del paisaje indicarían que se trata de ejemplares cuyas adaptaciones en los metapodios son concordantes para el paisaje pleistocénico de Pilauco dominado por suelos volcánicos blandos, con presencia de bosquetes dispersos en grandes extensiones de praderas de gramíneas.

  2. Seasonal mercury concentrations and δ15N and δ13C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

    International Nuclear Information System (INIS)

    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes (δ15N and δ13C). Mercury concentrations in Lenga sediments ranged from 0.4 ± 0.1 to 13 ± 3 mg/kg, while those in Tubul sediments ranged from 0.02 ± 0.01 to 0.07 ± 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of δ13C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: ► Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. ► Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. ► Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. ► Interspecific variation in δ13C signatures indicated different feeding modes. ► Organic forms of Hg in invertebrates were mainly related to the carbon sources.

  3. Seasonal changes in the photosynthetic performance of two evergreen Nothofagus species in south central Chile Cambios estacionales en el desempeño fotosintético de dos especies siempreverdes de Nothofagus en el centro sur de Chile

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    RAFAEL ZÚÑIGA

    2006-12-01

    Full Text Available The evergreen Nothofagus dombeyi and Nothofagus nitida are important members of the temperate Chilean rainforest. They seldom grow together in nature. Nothofagus nitida is more susceptible to excess light and drought than N. dombeyi. We postulate that the different properties of the photosynthetic apparatus under common garden conditions of these species could explain their contrasting habitat preferences. The two species growing in a common garden in south central Chile were studied. The optimal photochemical efficiency (Fv/Fm of both species remained within normal values (»0.8 with the exception of a decrease in N. dombeyi at midday in summer, suggesting reversible reduction in photochemical efficiency of photosystem II (PSII. During summer the effective photochemical efficiency (F PSII, photochemical quenching (qP, photosynthesis (Amax, stomatal conductance (gs and transpiration rates (E in N. dombeyi were higher than in N. nitida. The highest increments in photoprotective pigments (zeaxanthin + antheraxanthin and lutein contents between predawn and midday were obtained in summer in N. dombeyi. In N. nitida a nocturnal retention of dissipative pigments, without a decrease in Fv/Fm, was found in winter. The results suggest that N. dombeyi showed a better photosynthetic performance than N. nitida under high light, high temperature, and drier conditions. These data support are consistent with the pioneer character of N. dombeyi and the semi-tolerant shade properties and more restricted distribution of N. nitida. These photosynthetic characteristics, along with their freezing and flooding resistance differences, may result from their habitat separationLas siempreverdes, Nothofagus dombeyi y Nothofagus nitida, representantes importantes de los bosques lluviosos templados de Chile, raramente crecen juntos en forma natural. Nothofagus nitida es más sensible al exceso de luz y déficit de agua que N. dombeyi. Se postula que diferentes propiedades

  4. New time-constraints on provenance, metamorphism and exhumation of the Bahía Mansa Metamorphic Complex on the Main Chiloé Island, south-central Chile Nuevas restricciones temporales sobre proveniencia, metamorfismo y exhumación del Complejo Metamórfico Bahía Mansa en la Isla Grande de Chiloé, centro-sur de Chile

    OpenAIRE

    Paul Duhart; Alberto C Adriasola

    2008-01-01

    The Coastal Ranges in the western part of the Chiloé Archipelago represent an emerged forearc high at the subduction front of south-central Chile. Prior to the Cenozoic framework of the subducting Farallón and Nazca plates beneath the South American plate, the history of the metamorphic basement in the Coastal Ranges involves episodes of subduction and/or accretion of oceanic and ensialic material along the proto-Pacific margin of Gondwana. Along different segments of the Main Chiloé Island t...

  5. Valinia INIA, a New Early Storage Onion Variety for Central South Chile Valinia INIA, una Nueva Variedad de Cebolla de Guarda Precoz para la Zona Centro Sur de Chile

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    María Inés González A

    2012-03-01

    Full Text Available In Central South Chile, storage onion varieties (Allium cepa L. sold domestically usually begin the maturation process in March, which implies that a large proportion of bulbs do not mature adequately and do not resist prolonged storage. This situation led the Quilamapu vegetable program of the Instituto de Investigaciones Agropecuarias INIA to select an early maturing onion variety. This breeding method involved a recurrent selection with free plant crossing that began in 1994 on a population of 2000 plants of the 'Valenciana' commercial variety. Plants were first selected when they reached physiological maturity (tops down before 28 February, and then for shape, size, storage capacity, and single-centered bulbs. The result of the program was 'Valinia INIA', a type of Valenciana onion variety: early maturing, medium-sized bulb, spherical, yellow, and resistant to sprouting during storage. From the 2001-2002 to the 2008-2009 season, variety assays were carried out to compare 'Valinia INIA' with commercial cultivars, i.e., 'Sintética 14', 'Grano de Oro', and 'Valenciana Cobra'. 'Valinia INIA' precocity exceeded the other varieties in all seasons with a mean of 1.5 wk ahead of 'Sintética 14', which is the earliest commercial variety and more than 2 wk ahead of the other two. Its yield is similar to 'Valenciana Cobra' and higher than the other two varieties. Its storage capacity is similar to 'Grano de Oro' and 'Sintética 14', but greater than 'Valenciana Cobra'.En la zona centro sur de Chile es habitual que las variedades de cebolla (Allium cepa L. de guarda que se comercializan en el pais inicien el proceso de maduración preferentemente en marzo, lo que conlleva a que una gran proporción de bulbos no madure adecuadamente, no resistiendo el almacenaje por un tiempo prolongado. Esta situación llevó al programa de hortalizas del Instituto de Investigaciones Agropecuarias INIA Quilamapu a la selección de una variedad de cebolla de madurez

  6. Using 137Cs and 210Pbex and other sediment source fingerprints to document suspended sediment sources in small forested catchments in south-central Chile

    International Nuclear Information System (INIS)

    A study of the impact of forest harvesting operations on sediment mobilization from forested catchments has been undertaken in south-central Chile. The study focused on two sets of small paired catchments (treatment and control), with similar soil type, but contrasting mean annual rainfall, located about 400 km apart at Nacimiento (1200 mm yr−1) and Los Ulmos (2500 mm yr−1). The objective was to study the changes in the relative contribution of the primary sources of fine sediment caused by forestry operations. Attention focused on the pre-harvest and post-harvest periods and the post-replanting period was included for the Nacimiento treatment catchment. The sediment source fingerprinting technique was used to document the contributions of the potential sources. Emphasis was placed on discriminating between the forest slopes, forest roads and channel erosion as potential sources of fine sediment and on assessing the relative contributions of these three sources to the sediment yield from the catchments. The fallout radionuclides (FRNs) 137Cs and excess lead-210, the environmental radionuclides 226Ra and 40K and soil organic matter (SOM) were tested as possible fingerprints for discriminating between potential sediment sources. The Kruskal–Wallis test and discriminant function analysis were used to guide the selection of the optimum fingerprint set for each catchment and observation period. Either one or both of the FRNs were selected for inclusion in the optimum fingerprint for all datasets. The relative contribution of each sediment source to the target sediment load was estimated using the selected fingerprint properties, and a mixing model coupled with a Monte Carlo simulation technique that takes account of uncertainty in characterizing sediment source properties. The goodness of fit of the mixing model was tested by comparing the measured and simulated fingerprint properties for the target sediment samples. In the Nacimiento treatment catchment the

  7. On the generation of coastal lows in central Chile

    International Nuclear Information System (INIS)

    Previous studies of the coastal-low occurrences in central Chile have been aimed at the formulation of a conceptual model to explain observed features in connection with applied studies. The most prominent weather pattern associated with CL occurrences, (type A), coincides with the onset of a warm, middle-troposphere ridge over central Chile, and a surface high over northern Argentina. The synoptic forcing of the low is related to weak frontal disturbances that travel equatorwards. They result in a thickening of the marine layer that becomes blocked by the coastal escarpment, at the time of the onset of the ridge aloft. The blocking of the stable air above the subsidence inversion by the Andes is also hypothesized. The analysis of the subsidence inversion, the geometry of the coastal and Andes mountain ranges, and a scale analysis of the non-dimensional governing equations for the generation of the coastal lows, following the approach of Reason and Steyn (1990); leads to the conclusion that both blocking actions are strong and persistent in central Chile. An interactive mechanism between the upper and lower blocking effects is postulated to explain the cyclonic vorticity and the initial steering of the coastal lows. The scale analysis of the governing equations for the propagation stage of the low suggests that, departing for the South African case, non-linearity is important here, and that solitary Kelvin waves could be expected. Theoretical phase propagation speeds and Rossby radii are found to range between 8 and 15 m s-1 and 100-250 km, respectively. The importance of strong southerly winds ahead of the low and weak winds at its trailing edge is also stressed, as another major departure from the coastal-low behaviour elsewhere. (author). 17 refs, 4 figs, 4 tabs

  8. Low prevalence of Factor V Leiden and the prothrombin G20210A mutation in a healthy population from the central-south region of Chile Baixa prevalência do Fator V Leiden e da mutação da protrombina G20210A em uma população sã da região centro-sul do Chile

    OpenAIRE

    Iván Palomo; Fabian Segovia; Daniela Parra; Marcelo Alarcón; Edgardo Rojas

    2009-01-01

    Thrombosis is a result of the interaction between predisposing genetic polymorphisms and acquired risk factors. The two prothrombotic polymorphisms which are most frequently associated with thrombosis are factor V (FV) Leiden and the prothrombin (PT) G20210A mutation. The objective of this work was to investigate the prevalence of both factors in the central-south region of Chile. Determination of the frequency was carried out by means of a genetic analysis of 1200 healthy, non-native individ...

  9. Depositación atmosférica de nitrógeno en un transecto valle longitudinal-cordillera de Los Andes, centro-sur de Chile Atmospheric deposition of nitrogen in a transect from the Central Valley to Cordillera de Los Andes, south-central Chile

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    CARLOS E. OYARZÚN

    2002-03-01

    Osorno y Parque Nacional Puyehue, respectivamente. Los resultados se discuten en relación con los posibles efectos ambientales de las crecientes tasas de depositación atmosférica, sobre la acidificación y eutroficación del suelo y aguas subterráneas y de escorrentía, en el valle longitudinal del centro-sur de Chile.Agricultural-livestock activities in south-central Chile, could result in elevated emissions of inorganic N (mainly NH3 compounds into the atmosphere. Ammonia can be transported via air currents and deposited on the vegetation and soil. The present study evaluates the atmospheric deposition of nitrogen compounds (NO3- y NH4+ in the precipitation, in an altitudinal transect of 66 km long, from the vicinity of Osorno (40º 35' S, 72º 57' W, 55 m of altitude to Puyehue National Park, Cordillera de Los Andes (40º 46' S, 72º 11' W, 1,120 m of altitude. In seven sites, from June-1999 to May-2000, precipitation was recorded and water samples were collected monthly, for to determine pH, conductivity and NO3- and NH4+ concentrations. Annual precipitation increased from 1,103 mm near Osorno to 6,799 mm in Antillanca, Puyehue National Park. Annual mean values of pH showed little change from 6.3 in the central valley to 5.8 in the Cordillera de Los Andes. Conductivity showed the maximum values near Osorno (22.9 muS cm-1, intermediate values in transitional sites, and 11.3 muS cm-1 in the Cordillera de Los Andes. The annual mean concentrations of NO3-N changed between 52.3 mug L-1 in the agriculture-cattle area and 6.9 mug L-1 in temperate rainforests in Puyehue National Park. NH4+ concentrations changed between 699.4 mug L-1 in the Osorno sector to 37.8 mug L-1 in Cordillera de Los Andes. Inorganic-N values have a marked seasonal variation in the agricultural region with the maximum values in spring-summer and minimum in wintertime. Annual rates of atmospheric deposition of NO3-N fluctuated between 0.53 and 0.57 kg ha-1 yr-1, and the NH4-N between 6.4 and 2.8 kg

  10. Hábitos alimentarios de Dosidicus gigas (D' Orbigny, 1835 (Cephalopoda: Teuthoidea frente a la costa centro-sur de Chile Feeding habits of Dosidicus gigas (D'Orbigny, 1835 (Cephalopoda: Teuthoidea in the central-south coast off Chile

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    PATRICIO ULLOA

    2006-12-01

    Full Text Available Se estudiaron los hábitos alimentarios del calamar rojo Dosidicus gigas (D'Orbigny, 1835 frente a la costa de Chile centro-sur, durante el invierno del año 2005. Se examinaron un total de 52 estómagos, en todos los cuales había contenido alimentario. Los ejemplares provenían de pescas efectuadas por la flota arrastrera industrial que opera entre 36°39' S y 38°55'S sobre la merluza común Merluccius gayi (Guichenot 1848 y a una profundidad media de 290 m sobre la plataforma continental. Para la descripción del espectro trófico, alimento principal y el establecimiento de las eventuales diferencias sexuales u ontogenéticas en la frecuencia de aparición de los ítemes presa, se utilizaron los métodos numérico, gravimétrico, de frecuencia de ocurrencia, índice de importancia relativa (IIR e índice de similitud porcentual (ISP. No se observaron diferencias sexuales ni ontogenéticas en la frecuencia de aparición de los ítemes presa. Los resultados muestran que D. gigas es un depredador oportunista, principalmente ictiófago, y secundariamente malacófago (incluye el canibalismo y carcinófago. Se discuten los eventuales motivos e implicancias de tal conductaA study on the feeding habits of the jumbo squid Dosidicus gigas (D'Orbigny, 1835 was carried out during the winter season 2005, in waters of the Chilean central and southern Pacific. A total of 52 jumbo squid stomachs from the fishing of the continental slope were collected and examined, in the Eighth and Ninth regions, between 36°40' S and 38°55'S, at an average depth of 290 m. To determine the trophic spectrum, the feeding preferences and the importance of the sex and ontogenetic condition in the diet, the numeric, gravimetric, frequency of occurrence methods, and the index of relative importance and dietary similarity were utilized. The frequency of the prey did not vary with relation to the sex and ontogenetic conditions, and was besides a hight trophic similarity in such

  11. Mortalidad natural de larvas de merluza común (Merluccius gayi gayi frente a Chile centro-sur en relación a su distribución espacial y grado de agregación Natural mortality of chilean hake (Merluccius gayi gayi larvae of central-south Chile in relation to their spatial distribution and patchiness

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    Cristian Vargas

    1996-01-01

    Full Text Available Existe escasa información sobre la ecología y sobrevivencia de estados larvales de merluza común frente a las costas de la VIII Región, Chile. Debido a que la agregación puede ser un factor determinante en la depredación de larvas de peces, en el presente trabajo se estudia su influencia en la mortalidad natural instantánea de larvas de merluza común (Merluccius gayi gayi Guichenot, 1848, estimada a través del modelo mortalidad-agregación de McGurk (1986. Las muestras (red bongo 500µ fueron obtenidas durante un crucero efectuado en la zona costera del centro-sur de Chile (36º22'S _ 37º10'S durante septiembre de 1991. La tasa de mortalidad natural instantánea fluctuó entre 0,1 y 0,38 d-1 para larvas en un rango de tallas de 4 a 11 mm de longitud estándar. Los valores de mortalidad obtenidos a través del modelo de interacción mortalidad-agregación (McGurk, 1986, revelaron que la distribución espacial (agregación podría influenciar considerablemente a la mortalidad, especialmente en larvas de mayor longitud (> 9 mm.At the present time limited information is available about ecology and survival of Chilean hake larvae off coast from VIII Region, Chile. Because spatial patchiness of larvae may be an important factor on the predation of fish larvae, its influence on the instantaneous natural mortality of larval Chilean hake (Merluccius gayi gayi Guichenot, 1848 was studied using the mortality-patchiness model (McGurk, 1986. Samples (bongo net 500µ were taken during a survey carried out in the coastal zone off Central-South Chile (36º22'S _ 37º10'S during september 1991. The natural mortality for larvae between 4 to 11 mm of standard length fluctuated between 0,1 and 0,38 d-1. The mortality values obtained using the mortality-patchiness model (McGurk, 1986, showed that the spatial distribution (patchiness would influence the larval mortality, specially in the largest ones (> 9 mm.

  12. Hábitos alimentarios de Dosidicus gigas (D' Orbigny, 1835) (Cephalopoda: Teuthoidea) frente a la costa centro-sur de Chile Feeding habits of Dosidicus gigas (D'Orbigny, 1835) (Cephalopoda: Teuthoidea) in the central-south coast off Chile

    OpenAIRE

    PATRICIO ULLOA; MARTA FUENTEALBA; VÍCTOR RUIZ

    2006-01-01

    Se estudiaron los hábitos alimentarios del calamar rojo Dosidicus gigas (D'Orbigny, 1835) frente a la costa de Chile centro-sur, durante el invierno del año 2005. Se examinaron un total de 52 estómagos, en todos los cuales había contenido alimentario. Los ejemplares provenían de pescas efectuadas por la flota arrastrera industrial que opera entre 36°39' S y 38°55'S sobre la merluza común Merluccius gayi (Guichenot 1848) y a una profundidad media de 290 m sobre la plataforma continental. Para ...

  13. Education with ICT in South Korea and Chile

    Science.gov (United States)

    Sanchez, Jaime; Salinas, Alvaro; Harris, Jordan

    2011-01-01

    This article presents a linear-analytical case study on the development of ICT within the educational systems of Chile and South Korea. Through a comprehensive meta-data analysis and bibliographic review, we collected information on both educational systems and their ICT adoption policies. Key differences necessary to understand how both countries…

  14. Miocene Vetigastropoda and Neritimorpha (Mollusca, Gastropoda) of central Chile

    Science.gov (United States)

    Nielsen, Sven N.; Frassinetti, Daniel; Bandel, Klaus

    2004-09-01

    Species of Vetigastropoda (Fissurellidae, Turbinidae, Trochidae) and one species of Neritimorpha (Neritidae) from the Navidad area, south of Valparaı´so, and the Arauco Peninsula, south of Concepción, are described. Among these, the Fissurellidae comprise Diodora fragilis n. sp., Diodora pupuyana n. sp., two additional unnamed species of Diodora, and a species resembling Fissurellidea. Turbinidae are represented by Cantrainea sp., and Trochidae include Tegula (Chlorostoma) austropacifica n. sp., Tegula (Chlorostoma) chilena n. sp., Tegula (Chlorostoma) matanzensis n. sp., Tegula (Agathistoma) antiqua n. sp., Bathybembix mcleani n. sp., Gibbula poeppigii [Philippi, 1887] n. comb., Diloma miocenica n. sp., Fagnastesia venefica [Philippi, 1887] n. gen. n. comb., Fagnastesia matanzana n. gen. n. sp., Calliostoma mapucherum n. sp., Calliostoma kleppi n. sp., Calliostoma covacevichi n. sp., Astele laevis [Sowerby, 1846] n. comb., and Monilea riorapelensis n. sp. The Neritidae are represented by Nerita (Heminerita) chilensis [Philippi, 1887]. The new genus Fagnastesia is introduced to represent low-spired trochoideans with a sculpture of nodes below the suture, angulated whorls, and a wide umbilicus. This Miocene Chilean fauna includes genera that have lived at the coast and in shallow, relatively warm water or deeper, much cooler water. This composition therefore suggests that many of the Miocene formations along the central Chilean coast consist of displaced sediments. A comparison with different fossil and Recent faunas from around the Pacific and South America indicates that the vetigastropod and neritid fauna from the Miocene of Chile has only minor affinities with taxa living near New Zealand, Argentina, and the tropical eastern Pacific at that time.

  15. Nitrogen fixation in four dryland tree species in central Chile

    International Nuclear Information System (INIS)

    Results are presented from a 5-year experiment using 15N-enriched fertilizer to determine N2 fixation in four tree species on degraded soils in a Mediterranean-climate region of central Chile in which there are 5 months of drought. Species tested included three slow-growing but long-lived savannah trees native to southers South America, (acacia caven, Prosopic alba and P. chilensis; Mimosoideae), and Tagasaste (Chamaecytisus proliferus ssp. palmensis; Papilonoideae), a fast-growing but medium-lived tree from the Canary Islands. Tagasaste produced four- to twenty-fold more biomass than the other species, but showed declining N2 fixation and biomass accumulation during the 5th year, corresponding to the juvenile-to-adult developmental transition. Nitrogen content was significantly higher in Tagasaste and Acacia caven than in the other species. The data revealed inter-specific differences in resource allocation and phenology of N2 fixation rarely detailed for woody plants in dryland regions. (author)

  16. Spatio-temporal distribution of spionids (Polychaeta-Spionidae in an estuarine system in south-central Chile Distribución espacio-temporal de los espiónidos (Polychaeta-Spionidae en un sistema de estuarios del centro sur de Chile

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    MAURICIO DÍAZ-JARAMILLO

    2008-12-01

    Full Text Available This study is based on the identification and distribution of spionid polychaetes in relation to abiotic characteristics of the environment at the mouth of the Valdivia-Tornagaleones estuary in south-central Chile. Four samplings were carried out in 2005, in which eight species were identified including Aquilaspio peruana, Boccardia polybranchia, Carazziella carrascoi, Dipolydora socialis, Minuspio patagónica, Rhynchospio glutaea, Scolelepis quinquedentata and Spiophanes sp. As it is typical of other estuaries in south central Chile, spionids were an important component of the macroinfauna of the Valdivia estuary. The distribution of the Spionidae family in the system showed higher species richness in the outer reach of the estuary but higher abundance (number of specimens at the inner reach. The distributional pattern of the polychaetes did not vary throughout the year, exhibiting strong spatial zonation with three significantly different assemblages. Minuspio patagónica, A. peruana and C. carrascoi contributed to the similarity between these three groups, as well as to the formation of a general component in the macroinfauna. Sedimentological and depth variables, as well as sedimentary organic material were only marginally related to the distribution of spionids. Results showed that bottom salinity was the environmental variable responsible for spatial differentiation of spionids in the three groups, which permit to differentiate the outer-reach species from those in the internal area of the estuary. The significant contribution of spionids to the total component of macroinfauna in the studied area shows that these species are a significant component of the estuarine and transition areas in the southwest Pacific coast.El estudio se desarrolla en base a la identificación y distribución de Spionidae y su relación con las características abióticas del medio, en la desembocadura del sistema estuarial Valdivia-Tornagaleones (Chile. Se

  17. Effect of Compost Application on Some Properties of a Volcanic Soil from Central South Chile Efecto de la Aplicación de Compost sobre Algunas Propiedades de un Suelo Volcánico de La Región Centro-Sur de Chile

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    Pedro José Valarini

    2009-09-01

    Full Text Available Soil compost application is a common soil management practice used by small farmers of Central-South Chile that produces positive effects on soil properties and also promotes presence and activity of arbuscular mycorrhizal fungi (AMF. This fungi form symbiosis with plant roots improving plant nutrition, as well as producing glomalin, a glycoprotein that has been associated with soil aggregation stability. Therefore, the aim of this study was to evaluate, in an Ultisol from Central-South Chile, the effect of different doses of compost on some soil characteristics at the end of the third year of a crop sequence including wheat (Triticum aestivum L., bean (Phaseolus vulgaris L., and grassland (Lolium multiflorum Lam. associated with Trifolium repens L.. Studied soil characteristics included chemical (pH, available-P, organic C, biological (C and N biomass, AMF spore number, root colonization percentage, mycelium length, and glomalin content, as well as physical parameters (water holding capacity [WHC], and water stable aggregates [WSA]. Results showed that, in general, compost application increased soil pH, mycorrizal roots, mycelium length, glomalin levels, and WSA. Significant relationships were found between C and N biomass, C biomass and WSA, C biomass and glomalin, WSA and WHC, among others. Results suggest that compost application to this type of soil is a feasible option as a fertilizer substitute, and a way to avoid soil erosion by small local farmers involved in organic agriculture.La aplicación de compost al suelo, práctica habitual en predios de pequeños agricultores de la región centro-sur de Chile, produce efectos positivos en sus propiedades y promueve la presencia y actividad de los hongos micorrícicos arbusculares (AMF. Estos hongos forman simbiosis con las raíces de las plantas mejorando su nutrición y además producen una glicoproteína llamada glomalina, la cual ha sido relacionada con la estabilidad de los agregados de

  18. The role of sediment composition and behavior under dynamic loading conditions on slope failure initiation: a study of a subaqueous landslide in earthquake-prone South-Central Chile

    Science.gov (United States)

    Wiemer, Gauvain; Moernaut, Jasper; Stark, Nina; Kempf, Philipp; De Batist, Marc; Pino, Mario; Urrutia, Roberto; de Guevara, Bruno Ladrón; Strasser, Michael; Kopf, Achim

    2015-07-01

    Subaqueous slope failure mechanisms are still poorly understood partly because they are difficult to study due to the remote location of submarine landslides. Landslides in lakes are smaller in size and more readily accessible and therefore represent a good alternative to their marine counterparts. Lake Villarrica, located in South-Central Chile, experienced significant slope failure and serves here as an exemplary study area for subaqueous landslide initiation mechanisms in tectonically active settings. Coring and CPTU testing were undertaken with the MARUM free-fall CPTU deployed adjacent to the coring sites where all lithological units involved in the slope failure were sampled. Using geotechnical methods such as pseudo-static factor of safety analysis and cyclic triaxial testing, three types of soils (i.e., diatomaceous ooze, volcanic ash, and quick clay) were analyzed for their role in slope failure, and earthquake shaking was identified as the primary trigger mechanism. The investigated landslide consisted of two distinct phases. During the first phase, slope failure was initiated above a tephra layer. In the second phase, retrogression led to the shoreward extension of the slide scarp along a second failure plane located in a stratigraphically deeper, extremely sensitive lithology (i.e., quick clay). Results show that liquefaction of buried tephra layers was unlikely, but such layers might still have contributed to a reduction in shear strength along the contact area with the neighboring sediment. Furthermore, cyclic shaking-induced pore pressure in diatomaceous ooze may be similar to that in granular soils. We generally infer that failure mechanisms observed in this study are equally important for landslide initiation in submarine settings as diatomaceous ooze intercalated with volcanic ash may be abundantly present along active continental margins.

  19. The evolution of seabirds in the Humboldt Current: new clues from the Pliocene of Central Chile.

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    Martín Chávez Hoffmeister

    Full Text Available BACKGROUND: During the last decade, new Neogene fossil assemblages from South America have revealed important clues about the evolution of seabird faunas in one of the major upwelling systems of the world: the Humboldt Current. However, most of this record comes from arid Northern Chile and Southern Peru and, in consequence, our knowledge of the evolutionary history of seabirds in the temperate transitional zone is negligible. A new Late Pliocene assemblage of fossil birds from the coastal locality of Horcon in Central Chile offers a unique opportunity to fill this gap. PRINCIPAL FINDINGS: Isolated bones of a medium-sized penguin are the most abundant bird remains. Morphological and cladistic analyses reveal that these specimens represent a new species of crested penguin, Eudyptes calauina sp. nov. Eudyptes is a penguin genus that inhabit temperate and subantarctic regions and currently absent in central Chile. Additionally, a partial skeleton of a small species of cormorant and a partial tarsometatarsus of a sooty shearwater have been identified. CONCLUSION/SIGNIFICANCE: The Horcon fossils suggest the existence of a mixed avifauna in central Chile during the Pliocene in concordance with the latitudinal thermal gradient. This resembles the current assemblages from the transitional zone, with the presence of species shared with Northern Chile and Southern Peru and a previously unrecorded penguin currently absent from the Humboldt System but present in the Magellanic region. Comparison of Pliocene seabird diversity across the Pacific coast of South America shows that the Horcon avifauna represents a distinctive assemblage linking the living faunas with the Late Miocene ones. A comparison with the fossil record near the Benguela Current (west coast of southern Africa suggests that the thermic gradient could play an important role in the preservation of a higher diversity of cold/temperate seabirds in the Humboldt Current.

  20. The Evolution of Seabirds in the Humboldt Current: New Clues from the Pliocene of Central Chile

    Science.gov (United States)

    Chávez Hoffmeister, Martín; Carrillo Briceño, Jorge D.; Nielsen, Sven N.

    2014-01-01

    Background During the last decade, new Neogene fossil assemblages from South America have revealed important clues about the evolution of seabird faunas in one of the major upwelling systems of the world: the Humboldt Current. However, most of this record comes from arid Northern Chile and Southern Peru and, in consequence, our knowledge of the evolutionary history of seabirds in the temperate transitional zone is negligible. A new Late Pliocene assemblage of fossil birds from the coastal locality of Horcon in Central Chile offers a unique opportunity to fill this gap. Principal Findings Isolated bones of a medium-sized penguin are the most abundant bird remains. Morphological and cladistic analyses reveal that these specimens represent a new species of crested penguin, Eudyptes calauina sp. nov. Eudyptes is a penguin genus that inhabit temperate and subantarctic regions and currently absent in central Chile. Additionally, a partial skeleton of a small species of cormorant and a partial tarsometatarsus of a sooty shearwater have been identified. Conclusion/Significance The Horcon fossils suggest the existence of a mixed avifauna in central Chile during the Pliocene in concordance with the latitudinal thermal gradient. This resembles the current assemblages from the transitional zone, with the presence of species shared with Northern Chile and Southern Peru and a previously unrecorded penguin currently absent from the Humboldt System but present in the Magellanic region. Comparison of Pliocene seabird diversity across the Pacific coast of South America shows that the Horcon avifauna represents a distinctive assemblage linking the living faunas with the Late Miocene ones. A comparison with the fossil record near the Benguela Current (west coast of southern Africa) suggests that the thermic gradient could play an important role in the preservation of a higher diversity of cold/temperate seabirds in the Humboldt Current. PMID:24621560

  1. Borage (Borago officinalis L. Response to N, P, K, and S Fertilization in South Central Chile Respuesta de Borraja (Borago officinalis L. a la Fertilización con N, P, K, y S en el Centro Sur de Chile

    Directory of Open Access Journals (Sweden)

    Marisol T. Berti

    2010-06-01

    Full Text Available Borage (Borago officinalis L. is an oilseed with a high gamma-linolenic acid (GLA content in its seed. The objective of this study was to determine the response of borage seed yield, oil content, and fatty acid composition to N, P, K, and S fertilizer treatments. Three experiments were conducted in Osorno (40º22’ S, 73º04’ W; 72 m.a.s.l., Chile. The first experiment was conducted during the 2005-2006 growing season, with four N rates (0, 100, 200, and 300 kg N ha-1, three P rates (0, 60, and 120 kg P2O5 ha-1 and two K rates (0 and 150 kg K2O ha-1. The second experiment was conducted in 2006-2007 and evaluated only the effect of four N rates (0, 50, 100 and 150 kg N ha-1 was evaluated because there was no response to P and K in the first experiment. The third experiment was conducted in the 2005-2006 and 2006-2007 and evaluated only two rates of S, 0 and 40 kg S ha-1. Seed yield was not affected by N, P, K, or their interactions in any of the experiments. As N rates increased GLA content increased. Mean seed yield increased to 98 kg ha-1 when applying 40 kg S ha-1. Results indicate that borage has a higher response to S applications than N. Further research is needed to determine the interactions between N and S applications, given that the experiments were conducted on soils with high P and K levels.La borraja (Borago officinalis L. es una oleaginosa con alto contenido de ácido gamma-linolénico (GLA en su semilla. El objetivo de este estudio fue determinar la respuesta en rendimiento de semillas, contenido y composición del aceite de borraja, a la fertilización con N, P, K y S. Tres experimentos fueron conducidos en Osorno (40º22’ S, 73º04’ O; 72 m.s.n.m., Chile. El primer experimento fue conducido en la temporada 2005-2006, con cuatro dosis de N (0, 100, 200 y 300 kg N ha-1, tres dosis de P (0, 60 y 120 kg P2O5 ha-1 y dos dosis de K (0 y 150 kg K2O ha-1. El segundo experimento fue conducido en el 2006-2007, cuando sólo se

  2. Patrones reproductivos del lobo marino común, Otaria flavescens (Shaw 1800, en el centro-sur de Chile Breeding patterns in southern sea lions, Otaria flavescens (Shaw 1800, in south-central Chile

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    HÉCTOR J PAVÉS

    2005-12-01

    Full Text Available El desfase latitudinal de los eventos reproductivos en Otaria flavescens sugiere la existencia de una adaptación fisiológica y conductual a condiciones ambientales locales. La identificación de cambios en los patrones conductuales intraespecíficos frente a modificaciones ambientales sugieren una relación entre estos. Se pretende revisar los patrones reproductivos del O. flavescens, determinando la existencia de una sincronización y estabilidad en ellos durante las temporadas 1996-1997 y 1997-1998 en la colonia de Punta Lobería, Chile. Se realizaron observaciones directas de las agrupaciones y conductas reproductivas empleando binoculares, y apoyadas por el uso de material fílmico y fotográfico. Los resultados evidenciaron modificaciones en, (a el número de harenes (de 28 disminuye a 19, (b la distribución espacial de los harenes (70 % de los harenes durante 1997-1998 se establecieron en el lado norte de la playa reproductiva, durante la temporada anterior estos se distribuyeron a lo largo de toda la playa, (c proporción etaria (un macho: 12 hembras: un juvenil: siete cachorros, desciende a un macho: nueve hembras: dos juveniles: seis cachorros, (d índice de poliginia (de 12,4 a 7,8 HPMT y de 11 a 9 HP, y (e la población organizada en harenes (disminución del 10,3 %. Estas variaciones estarían relacionadas con la reducción del espacio óptimo para el establecimiento de harenes debido a la incorporación de suelo/roca posterior a un derrumbe invernal. Los patrones conductuales reproductivos que se mantuvieron invariables durante las temporadas fueron, (a la estacionalidad de los harenes (constitución durante la cuarta semana de diciembre y disolución en la cuarta semana de febrero, (b el período de partos (inicio durante la segunda semana de enero, finalización durante la cuarta semana de enero, y (c el período de cópulas (inicio durante la tercera semana de enero, finalización durante la segunda semana de febrero. Por lo

  3. The tomato borer, Tuta absoluta, invading the Mediterranean Basin, originates from a single introduction from Central Chile.

    Science.gov (United States)

    Guillemaud, Thomas; Blin, Aurélie; Le Goff, Isabelle; Desneux, Nicolas; Reyes, Maritza; Tabone, Elisabeth; Tsagkarakou, Anastasia; Niño, Laura; Lombaert, Eric

    2015-01-01

    The Lepidopteran pest of tomato, Tuta absoluta, is native to South America and is invasive in the Mediterranean basin. The species' routes of invasion were investigated. The genetic variability of samples collected in South America, Europe, Africa and Middle East was analyzed using microsatellite markers to infer precisely the source of the invasive populations and to test the hypothesis of a single versus multiple introductions into the old world continents. This analysis provides strong evidence that the origin of the invading populations was unique and was close to or in Chile, and probably in Central Chile near the town of Talca in the district of Maule. PMID:25667134

  4. Chile.

    Science.gov (United States)

    1988-09-01

    Chile is a long (2650 miles), narrow (250 miles at widest point) country sandwiched between the Andes mountains and the Pacific. The northern desert is rich in copper and nitrates; the temperate middle region is agricultural and supports the major cities, including Santiago, the capital, and the port of Valparaiso; and the southern region is a cold and damp area of forests, grasslands, lakes, and fjords. The country is divided into 12 administrative regions. Chile's population of 12.5 million are mainly of Spanish or Indian descent or mestizos. Literacy is 92.3%, and the national language is Spanish. Infant mortality is 18.1/1000, and life expectancy is 68.2 years. 82% of the people are urban, and most are Roman Catholics. Chile was settled by the Spanish in 1541 and attached to the Viceroyalty of Peru. Independence was won in 1818 under the leadership of Bernardo O'Higgins. In the 1880s Chile extended its sovereignty over the Strait of Magellan in the south and areas of southern Peru and Bolivia in the north. An officially parliamentary government, elected by universal suffrage, drifted into oligarchy and finally into a military dictatorship under Carlos Ibanez in 1924. Constitutional government was restored in 1932. The Christian Democratic government of Eduardo Frei (1964-70) inaugurated major reforms, including land redistribution, education, and far-reaching social and economic policies. A Marxist government under Salvador Allende lasted from 1970 to 1973 when the present military government of General Pinochet Ugarte took power, overthrew Allende, abolished the Congress, and banned political parties. It has moved the country in the direction of a free market economy but at the cost of systematic violations of human rights. A new constitution was promulgated in 1981, and congressional elections have been scheduled for October, 1989. A "National Accord for Transition to Full Democracy" was mediated by the Catholic Church in 1985. The social reforms of the

  5. Recent temperature trends in the South Central Andes reconstructed from sedimentary chrysophyte stomatocysts in Laguna Escondida (1742 m a.s.l., 38°28 S, Chile)

    Science.gov (United States)

    De Jong, R.; Schneider, T.; Hernández-Almeida, I.; Grosjean, M.

    2016-02-01

    In this study we present a quantitative, high resolution reconstruction of past austral winter length in the Chilean Andes at 38°S from AD 1920 to 2009. For Laguna Escondida, a nearly pristine lake situated on the flanks of the Andes at 1740 m above sea level, past variability in the duration of the winter season (Days T4 °C) was reconstructed. Because high elevation meteorological stations are absent in this region, the reconstruction provides novel insights into recent temperature trends in the central-southern Andes. As a cold-season temperature proxy, we used chrysophyte stomatocysts. This novel proxy for cold season temperature was so far applied successfully in the European Alps and Pyrenees but has not yet been tested in the Southern Hemisphere. The reconstruction in this study was based on a newly developed Transfer Function to estimate Days T4 °C (number of consecutive days with surface water temperatures at or below 4 °C) from sedimentary stomatocyst assemblages (R2boot = 0.8, RMSEPboot = 28.7 days (= half the standard deviation)). To develop a high quality TF model, sediment traps and thermistors were placed in thirty remote lakes along an altitude gradient (420-2040 m a.s.l.). Complete materials and data were collected in 24 lakes after one year. Detailed statistical analyses indicate that modern stomatocysts primarily respond to the length of the cold season. The TF model was then applied to the sedimentary stomatocysts from a 210Pb-dated short core of L. Escondida. Comparison to independent reanalysis data showed that reconstructed changes in Days T4°C provides detailed information on winter-spring temperature variability since AD 1920. The reconstruction shows that recent warming (onset in AD 1980) in the southern Chilean Andes was not exceptional in the context of the past century. This is in strong contrast to studies from the Northern Hemisphere. The finding is also in contrast to the cooling temperature trends which were detected using

  6. Eighty Years of History of the Central Bank of Chile

    OpenAIRE

    Vittorio Corbo; Leonardo Hernández

    2005-01-01

    The Central Bank of Chile was founded in 1925, to provide the country with an institution that could stabilize the currency, regulate interest and discount rates, and avoid disruptions in the country’s financial, industrial and economic development (Decree Law Nº486, August 22, 1925). But a weak institutional framework meant that the Bank, far from ameliorating these problems, aggravated them, leading to decades of high and persistent inflation. Inflation became under control only during the ...

  7. Seasonal mercury concentrations and {delta}{sup 15}N and {delta}{sup 13}C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Jaramillo, Mauricio, E-mail: mdiazjaramillo@conicet.gov.ar [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Munoz, Claudia; Rudolph, Ignacio [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Servos, Mark [Department of Biology, University of Waterloo, ON (Canada); Barra, Ricardo [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile)

    2013-01-01

    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C). Mercury concentrations in Lenga sediments ranged from 0.4 {+-} 0.1 to 13 {+-} 3 mg/kg, while those in Tubul sediments ranged from 0.02 {+-} 0.01 to 0.07 {+-} 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p < 0.05), but not by species or season for each estuary (p > 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of {delta}{sup 13}C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: Black-Right-Pointing-Pointer Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. Black-Right-Pointing-Pointer Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. Black-Right-Pointing-Pointer Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. Black-Right-Pointing-Pointer Interspecific variation in {delta}{sup 13}C signatures indicated different feeding modes. Black

  8. New time-constraints on provenance, metamorphism and exhumation of the Bahía Mansa Metamorphic Complex on the Main Chiloé Island, south-central Chile Nuevas restricciones temporales sobre proveniencia, metamorfismo y exhumación del Complejo Metamórfico Bahía Mansa en la Isla Grande de Chiloé, centro-sur de Chile

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    Paul Duhart

    2008-01-01

    Full Text Available The Coastal Ranges in the western part of the Chiloé Archipelago represent an emerged forearc high at the subduction front of south-central Chile. Prior to the Cenozoic framework of the subducting Farallón and Nazca plates beneath the South American plate, the history of the metamorphic basement in the Coastal Ranges involves episodes of subduction and/or accretion of oceanic and ensialic material along the proto-Pacific margin of Gondwana. Along different segments of the Main Chiloé Island the thermal record of the metamorphic basement rocks includes regional metamorphism, exhumation and finally magmatism. Detrital zircons conventional U-Pb ages from a pelitic schist of the Central Segment of the Main Chiloé Island constrain the maximum possible sedimentation age to the Carboniferous (310 Ma. Other concordant zircon fractions (360, 390 and 412 Ma suggest Ordovician primary sources. The sedimentary provenance of zircons could correspond to continental magmatic rocks of similar ages presently exposed in adjacent areas such as Nahuelbuta Mountains and Principal Cordillera and, additionally, from distal areas in the North-Patagonian and Deseado massifs. Widespread metamorphism in greenschist facies is well represented in the basement unit of the Main Chiloé Island. K-Ar and 40Ar/39Ar cooling ages in white mica range between 245 to 220 Ma, interpreted as near the peak of metamorphism during Middle to early Late Triassic times. Zircon and apatite fission-track (FT central ages in metamorphic rocks range from Late Jurassic (ca. 156 Ma to Eocene (ca. 38 Ma and are accompanied by relatively large dispersions. The modelling of the zircon FT single-grain age distributions depicts younger deconvoluted Late Cretaceous peak (ca. 80 Ma and the apatite modelling shows two populations, an older Late Cretaceous peak (ca. 64-91 Ma and a younger Eocene peak (ca. 3 8-5 3 Ma. The zircon and apatite Late Cretaceous peaks together with the presence of a marine

  9. Dublin South Central (DSC)

    LENUS (Irish Health Repository)

    O'Gorman, Clodagh S M

    2010-12-01

    Children who appear healthy, even if they have one or more recognized cardiovascular risk factors, do not generally have outcomes of cardiovascular or other vascular disease during childhood. Historically, pediatric medicine has not aggressively screened for or treated cardiovascular risk factors in otherwise healthy children. However, studies such as the P-Day Study (Pathobiological Determinants of Atherosclerosis in Youth), and the Bogalusa Heart Study, indicate that healthy children at remarkably young ages can have evidence of significant atherosclerosis. With the increasing prevalence of pediatric obesity, can we expect more health problems related to the consequences of pediatric dyslipidemia, hypertriglyceridemia, and atherosclerosis in the future? For many years, medications have been available and used in adult populations to treat dyslipidemia. In recent years, reports of short-term safety of some of these medications in children have been published. However, none of these studies have detailed long-term follow-up, and therefore none have described potential late side-effects of early cholesterol-lowering therapy, or potential benefits in terms of reduction of or delay in cardiovascular or other vascular end-points. In 2007, the American Heart Association published a scientific statement on the use of cholesterol-lowering therapy in pediatric patients. In this review paper, we discuss some of the current literature on cholesterol-lowering therapy in children, including the statins that are currently available for use in children, and some of the cautions with using these and other cholesterol-lowering medications. A central tenet of this review is that medications are not a substitute for dietary and lifestyle interventions, and that even in children on cholesterol-lowering medications, physicians should take every opportunity to encourage children and their parents to make healthy diet and lifestyle choices.

  10. Modelling the seasonal dynamics of the Peru-Chile Undercurrent off Central Chile (30-40°S)

    Science.gov (United States)

    Vergara, Odette A.; Echevín, Vincent; Sepúlveda, Héctor H.; Colas, Francois; Quiñones, Renato A.

    2016-07-01

    The seasonal variability of the hydrology and the poleward subsurface Peru-Chile Undercurrent (PCUC) off the central Chilean coast (29-41°S) were examined using a high-resolution regional model. The model realistically reproduced observed sea level variability, such as intense anticyclonic eddies, the offshore intensification of the poleward flow and the reduced nearshore equatorward flow during autumn, as well as the equatorward intensification of nearshore meandering flow during spring. Values for geostrophic eddy kinetic energy were high along the coast between 30° and 37°S, and lower south of this area. The modelled poleward undercurrent showed latitudinal variability in velocity and transport. The maximum average transport reported was 0.8 Sv near 30°S, consistent with previous modelling studies and estimations derived from in situ observations. The poleward reduction in undercurrent strength was shown to be partly generated by the poleward decrease in wind stress curl and by the formation of a westward jet near 35°S associated with westward-propagating eddies. A Lagrangian analysis of the modelled water parcels transported by the undercurrent shows that only 14-20% of the subsurface floats transported by the undercurrent upwelled into the surface layer within the subsequent six months after their release. The floats remaining within the subsurface layer were likely transported further south by the current, offshore by westward-propagating eddies or equatorward by the deeper part of the surface coastal current.

  11. Efecto de la fragmentación forestal sobre la estructura vegetacional de las poblaciones amenazadas de Legrandia concinna (Myrtaceae del centro-sur de Chile Effect of forest fragmentation on vegetation structure of Legrandia concinna (Myrtaceae threatened populations in south-central Chile

    Directory of Open Access Journals (Sweden)

    ADISON ALTAMIRANO

    2007-03-01

    tiempo a fin de evaluar la efectividad de determinadas estrategias de conservación para estas poblacionesHabitat fragmentation is one of the main threats to ecosystems integrity. In this study we assessed the influence of forest fragmentation on vegetation structure of populations of tree specie Legrandia concinna in south-central Chile. Occupancy pattern of Legrandia populations in remaining fragments of native forests was described, and relationship between landscape indices and vegetation structure variables were evaluated. Landscape indices, such as area, proximity mean index, shape and edge distance to fragment were applied to forest cover maps generated from a Landsat ETM+ satellite scene for the year 2001. Results showed high predominance of reduced size fragments, high isolation levels and regulars shapes of the fragments. Occupancy pattern suggests that Legrandia populations are found mainly in small and more isolated fragments. No significant difference was found between fragment distribution with and without presence of Legrandia related to size and isolation. However, we found that size, isolation and distance to fragment edge are significantly related to the presence of this specie. As conservation measures for this specie, we propose to include populations with high disappearance risk in protected areas, promote ex situ conservation and set up a monitoring program. This study sets a precedent related by linking landscape scale information obtained from satellite imagery and vegetation structure information measured in the field with conservation status of threatened populations. This innovative method allows monitoring changes over time to assess effectiveness of conservation strategies for these populations

  12. Análisis de las tasas de captura de jurel (Trachurus symmetricus en la zona centro-sur de Chile (1987-1999 Jack mackerel (Trachurus symmetricus catch rate analysis in the central-south of Chile (1987-1999

    Directory of Open Access Journals (Sweden)

    Claudio Gatica

    2002-01-01

    Full Text Available Se analizaron los cambios en la Captura por Unidad de Esfuerzo (CPUE de la pesquería industrial de cerco de jurel (Trachurus symmetricus en la zona centro-sur de Chile entre 1987 y 1999. Se utilizaron dos unidades de esfuerzo de pesca para calcular las tasas de captura: días fuera de puerto y viajes con pesca. La flota se clasificó en cuatro estratos homogéneos mediante Análisis de Componentes Principales (ACP, utilizando una matriz de correlación de variables técnico-operacionales. Los dos primeros ejes del ACP explicaron 87,8% de la varianza, debido a la naturaleza altamente autocorrelacionada de las variables. Los estratos identificados se utilizaron como variables categóricas para estandarizar la CPUE a través de un Modelo Lineal General (MLG, previa transformación logarítmica de la CPUE. Los modelos ajustados a los datos explicaron sobre un 64% de la variabilidad observada, siendo el estrato el que explicó un mayor porcentaje de variabilidad: 24,6% en el caso de la CPUE basada en los días fuera de puerto y 42,6% en la CPUE basada en los viajes con pesca. Las dos series de CPUE indicaron diferentes tendencias entre 1987 y 1993, pero coincidieron en señalar una tendencia negativa de la CPUE entre 1994 y 1997. La clasificación por estratos de una flota heterogénea mediante ACP permitió mejorar el análisis de las tasas de captura, aunque la componente espacial debe ser tomada en cuenta en futuros estudios. A su vez, la unidad de esfuerzo de pesca puede tener un impacto notable en las tendencias de CPUE, particularmente si se considera como un índice de abundancia relativaCatch per unit effort (CPUE data from the jack mackerel fishery operating in central-south Chile and covering the period 1987-1999 are analyzed in order to detect changes in relative abundance. Two units for fishing effort were used to compute the catch rate: number of days outside port and the number of trips with capture. The fleet was classified in four

  13. Influencia del tamaño de la hembra en la duración e intensidad de la actividad reproductiva de Merluccius gayi gayi en la zona centro-sur de Chile Influence of female size on the duration and intensity of the reproductive activity of Merluccius gayi gayi off central-south Chile

    Directory of Open Access Journals (Sweden)

    Carolina Alarcón

    2004-11-01

    Full Text Available En poblaciones de peces la dinámica reproductiva es un proceso que depende del tamaño de los individuos, aspecto que tiene notable importancia en términos de la intensidad y duración de la actividad reproductiva. En este estudio se analiza la duración e intensidad de la actividad reproductiva en función del tamaño de las hembras de Merluccius gayi gayi (Guichenot, 1848 de la zona centro-sur de Chile, a partir de muestras obtenidas en 1998. Se calculó el índice gonadosomático (IGS, el índice gonádico específico (IGE, y el índice de duración e intensidad (IDI de actividad reproductiva mediante la medición anual del área bajo la curva del IGS, por grupos de tamaño (longitud total, cm. Se encontró una relación lineal entre el IGS y el IGE (r² = 0,980, sugiriendo que las diferencias observadas en los índices se debe a cambios en el peso de la gónada y no a variaciones en el peso total. La mayor actividad reproductiva ocurrió entre agosto y octubre, detectándose actividad reproductiva secundaria entre febrero y abril. El IDI es función del tamaño de la hembra, y se encontró que la duración e intensidad de la actividad reproductiva es descrita por un modelo log-normal (r² = 0,96; n = 17,418; p In fish populations, reproductive dynamics is a process depending on the body size of the females, and has notable importance on intensity and duration of reproductive activity. In this study, we analyzed the duration and intensity of reproductive activity as a function of the body size in Merluccius gayi gayi females from samples obtained in 1998 off central-south Chile. The gonadosomatic index (GSI, the specific gonadal index (SGI and the duration and intensity index (DII of reproductive activity were computed. The DII represents the area under the GSI of length classes over a year. A linear relationship between the GSI and the SGI was found (r² = 0.980, suggesting that the changes in the variables are due to changes in ovary

  14. Cambios en la morfometría bucal y su relación con la dieta de Thyrsites atun (Euphrasen, 1791 en el centro-sur de Chile Changes in mouth morphometries as related to the diet of Thyrsites atun (Euphrasen, 1791 from south-central Chile

    Directory of Open Access Journals (Sweden)

    FREDDY DUARTE

    2007-12-01

    don't present such a clear pattern. To verify these relationships in the fish Thyrsites atun, a total of 140 individuals were collected from industrial and semi-industrial landings in south-central Chile. The diet of T. atun was described by means of frequency, number and weight of preys, which were compared between sub-adult and adult fishes. We also measured mouth morphometry to compare them with the fish size and prey size. Mouth volume was also calculated to relate it with the number and weight of the ingested preys. Four prey species were found in their digestive tracts, Euphausia sp., Todarodes filippovae, Strangomera bentincki and Engraulis ringens, the latter being the most frequent prey (99.9 %. The mouth measures were dependent of predator body size. Equally, prey size turned out to be dependent of predator size, as well as of the mouth measures. Also, mouth volume was related positively with predator body size, and the number and the weight of the prey items were correlated with mouth size and volume. Thyrsites atun feeds in the neritic area on small fishes that live in schools. As size of T. atun increases so would increase the size of preys, and consequently when the mouth volume increases so does the quantity and biomass of prey items

  15. Patrones de abundancia, composición trófica y distribución espacial del ensamble de peces intermareales de la zona centro-sur de Chile Abundance, trophic composition and spatial distribution of the intertidal fish assemblage of South-central Chile

    Directory of Open Access Journals (Sweden)

    PABLO A QUIJADA

    2000-12-01

    Full Text Available En las costas de la zona centro-sur de Chile se han realizado una serie de estudios relacionados con la biología de los peces pelágicos de importancia económica. Por el contrario, el conocimiento acerca de los peces litorales es escaso. En el presente trabajo, se estudiaron los patrones de abundancia, distribución y composición trófica del ensamble de peces que habitan en el intermareal rocoso de la costa de la Octava Región. Esta zona fue muestreada periódicamente entre septiembre de 1998 y enero de 1999. Se capturaron un total de 374 individuos pertenecientes a 13 especies y 8 familias. La especie más abundante en esta zona fue el pejesapo Gobiesox marmoratus (Gobiesocidae seguido de Calliclinus geniguttatus (Labrisomidae, las que en conjunto aportaron el 54 % al número total de peces encontrados. Las restantes especies pertenecieron a las familias Blenniidae, Labrisomidae, Clinidae, Bovichthydae, Tripterygiidae, Ophiididae y Nototheniidae. La presencia de ejemplares en estado juvenil, principalmente de G. marmoratus, indica que estas áreas son muy importantes como zonas de reclutamiento. El análisis trófico indica que este ensamble se compone en su mayoría de especies carnívoras que se alimentan principalmente de crustáceos y gastrópodos, con la excepción de los blénidos Scartichthys viridis, el cual es herbívoro, e Hypsoblennius sordidus que presenta una dieta de tipo omnívoraOn the coast of South-central Chile, a number of studies have been undertaken focusing on the biology of economically important pelagic fishes. In contrast, the knowledge of coastal fishes is scarce. In the present study, we analysed the patterns of abundance, distribution and trophic composition of the intertidal fish assemblage that inhabits rocky intertidal areas along the coast of the Eighth Region. This zone was sampled periodically between September 1998, and January 1999. A total of 374 individuals belonging to 13 species and 8 families were

  16. Cambio del uso del suelo en el centro sur de Chile a fines del siglo XX: Entendiendo la dinámica espacial y temporal del paisaje Land use change in the south central Chile at the end of the 20th century: Understanding the spatio-temporal dynamics of the landscape

    Directory of Open Access Journals (Sweden)

    MAURICIO AGUAYO

    2009-01-01

    Full Text Available Los humanos han transformado gran parte de la superficie del planeta en los últimos 300 años. La tala de bosques, las prácticas agrícolas de subsistencia, la intensificación de la producción agrícola y la expansión de los centros urbanos han cambiado drásticamente el paisaje. En el centro y sur de Chile las transformaciones han estado asociadas, en un inicio, a la expansión de la frontera agropecuaria que permitió satisfacer tanto las necesidades internas como la creciente demanda externa por productos agrícolas. Posteriormente, un fuerte incentivo a la forestación, comandado por el Estado, generó un acelerado proceso de desarrollo forestal que explica, en gran medida, la actual configuración del paisaje en esta región. En este trabajo hemos analizados la dinámica espacial de los cambios en el uso del suelo ocurridos durante las últimas décadas en un área de 2.3 millones de hectáreas ubicada entre las regiones del Biobío y La Araucanía. Las coberturas del suelo fueron obtenidas a partir de dos imágenes Landsat correspondientes a los años 1979 y 2000. Los resultados confirman que las principales transformaciones del paisaje son consecuencia del desarrollo forestal, la mantención de los rubros agropecuarios y el crecimiento urbano e industrial. Asimismo, fue posible determinar que la pérdida del bosque nativo se debe, principalmente, a la expansión de las plantaciones forestales hacia los cordones montañosos andinos y costeros.Land use changes have transformed much of the Earth's surface in the last 300 years. Deforestation, intensification of agriculture, and urban sprawl have radically changed the preindustrial landscape. In south-central Chile, landscape change was initially related to the expansión of farming to address national needs and the growing international demand for agricultural products. Subsequently, prívate forestry, subsidized by the State, promoted the accelerated expansión of industrial

  17. Evolution of Parinacota volcano, Central Andes, Northern Chile

    Directory of Open Access Journals (Sweden)

    Jorge E. Clavero R.

    2004-12-01

    Full Text Available Parinacota is an active composite stratovolcano located in the Central Andes of Northern Chile (18°S. During its earlier stage (Parinacota 1 unit, Late Pleistocene, 300-70? ka rhyolitic to andesitic magmas were erupted, forming a voluminous lava-dome complex with its associated pyroclastic fans (mainly block-and-ash flow deposits, essentially deposited towards the Upper Lauca basin (West. It later evolved to a steep-sided composite stratocone (Parinacota 2 unit, Late Pleistocene-Holocene, 70?-8 ka, mainly formed by andesitic lava flows and scoria tephra fallout deposits.Around 8 ka ago the ancestral Parinacota volcano, built during Parinacota 1 and 2, partially collapsed towards the west, in a single and catastrophic event generating the outstanding Parinacota Debris Avalanche deposit.Soon after the collapse a new stratocone started to build with the emission of andesitic lava flows and pyroclastic flows, and their associated fallout deposits (Parinacota 3 unit, Holocene, La evolución del volcán Parinacota, Andes Centrales, norte de Chile. El volcán Parinacota es un estratovolcán activo ubicado en los Andes Centrales del norte de Chile (18°S. Durante su primera etapa de evolución (Unidad Parinacota 1, Pleistoceno Superior, 300-70? ka emitió magmas de composición riolítica a andesítica, formando un voluminoso complejo de lavas-domo con abanicos piroclásticos asociados (esencialmente depósitos de bloques y ceniza, distribuidos principalmente hacia la parte superior de la cuenca del río Lauca (oeste. Posteriormente, evolucionó a un estratocono compuesto, de fuertes pendientes (Unidad Parinacota 2, Pleistoceno-Holoceno, 70?-8 ka, formado principalmente por lavas y depósitos de caída andesíticos. Aproximadamente hace 8 ka el volcán Parinacota ancestral, construido durante las unidades Parinacota 1 y 2, colapsó parcialmente hacia el oeste, en un evento único y catastrófico generando el Depósito de Avalancha de Parinacota. Poco

  18. Low prevalence of Factor V Leiden and the prothrombin G20210A mutation in a healthy population from the central-south region of Chile Baixa prevalência do Fator V Leiden e da mutação da protrombina G20210A em uma população sã da região centro-sul do Chile

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    Iván Palomo

    2009-01-01

    Full Text Available Thrombosis is a result of the interaction between predisposing genetic polymorphisms and acquired risk factors. The two prothrombotic polymorphisms which are most frequently associated with thrombosis are factor V (FV Leiden and the prothrombin (PT G20210A mutation. The objective of this work was to investigate the prevalence of both factors in the central-south region of Chile. Determination of the frequency was carried out by means of a genetic analysis of 1200 healthy, non-native individuals. The mutation of FV Leiden was found in 1.25% of the population and the PT G20210A mutation in 1.33%. None of the individuals were homozygosis or had both polymorphisms. The prevalences of FV Leiden and the PT G20210A mutation are less common in the healthy population.A trombose pode ser o resultado da interação de polimorfismo genético e fatores de riscos adquiridos. Os polimosfirmos protrombóticos mais frequentes são fator V (FV Leiden e a mutação da protrombina (PT G20210A. O objetivo deste trabalho foi investigar a prevalência de ambos os polimorfismos na região centro-sul do Chile. Foram realizadas análises genéticas (PCR RFLP de 1.200 pessoas saudáveis, não nativas da região. Foram encontrados 1,25% de mutação do Fator V Leiden e 1,33% da mutação da protrombina G20210A. Não foi detectada homozigose em ambos os polimorfismos. A prevalência de FV Leiden e da mutação G20210A é baixa na população estudada.

  19. Macroalgas varadas sobre la superficie de una playa arenosa del sur de Chile: preferencias alimentarias y de habitat de juveniles y adultos de Orchestoidea tuberculata (Nicolet, (Amphipoda, Talitridae Stranded algal wracks on a sandy beach of south central Chile: feeding and habitat preferences of juveniles and adults of Orchestoidea tuberculata (Nicolet, (Amphipoda, Talitridae

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    CRISTIAN DUARTE

    2008-03-01

    temes alimentarios diferentes, los juveniles pueden evitar el canibalismo de los adultos, interacción biológica previamente demostrada para O. tuberculata. La diferencia notoria en los patrones de preferencia de juveniles y adultos de este anfípodo demuestra la importancia de considerar la variabilidad intraespecífica en este tipo de estudiosThe amphipod Orchestoidea tuberculata, is the numerically dominant scavenger in the upper intertidal levels of sandy beaches from south central Chile. The main food source for juveniles and adults of this amphipod are the macroalgae stranded on the beach. Experiments of food preferences were carried out to analyze the eventual partition on the most common macroalgae on that beaches {Durvillaea antárctica, Macrocystis pyrifera y Lessonia nigrescens by .juveniles and adults of this amphipod. While juveniles preferred to consume L. nigrescens, adults showed a significant preference for D. antárctica. Similar to the laboratory results, that of field studies shows that juveniles of O. tubercula ta did not show significant preferences between D. antárctica and M. pyrifera, while adults preferred to consume D. antárctica instead of M. pyrifera. That suggest that D. antárctica is an important source of food (and habitat, for adult amphipods. Due to the fact that L. nigrescens could not be included in the field experiments, the possibility that juveniles also prefer this macroalgae in those conditions remains as an open question. Although the reasons underlying the differences in the food preferences of juveniles and adults are unknown, two possibilities can be proposed: ontogenetic changes in the morphology of mouth structures used for feeding and/or ontogenetic changes in nutritional requirements. However, the fact that juveniles preferred to consume the macroalgae with the lowest nutritional content (L. nigrescens among the three species offered as food, suggest another explanation to the observed differences. This refers to the fact, that by

  20. La dieta y la fauna de parásitos metazoos del torito Bovichthys chilensis Regan 1914 (Pisces: Bovichthydae en la costa de Chile centro-sur: variaciones geográficas y ontogenéticas Diet and metazoan parasite fauna of the thornfish Bovichthys chilensis Regan 1914 (Pisces: Bovichthydae on the coast of central-south Chile: geographical and ontogenetic variations

    Directory of Open Access Journals (Sweden)

    GABRIELA MUÑOZ

    2002-12-01

    variación geográfica del parasitismo de los toritos adultos, para dilucidar si en esta especie de hospedador el eje ontogenético es o no más importante que el geográfico para explicar las variaciones de la fauna parasitaria.Knowledge on what, how much, when and where hosts eat and live should help to understand the changes that occur in parasite communities because transmission of endoparasites is tightly linked to diet composition as well as ectoparasites are to the use that hosts make of the habitat. Thus, geographical and ontogenetic variations in diet and parasite fauna of the thornfish Bovichthys chilensis are described, and discussed taking into account the ontogenetic shifts in this host's niche. A total 122 individuals: 108 juveniles collected from the intertidal zone at four localities along the south-central coast of Chile (between 33º and 40º S, and 14 adults collected from the shallow subtidal at a fifth locality (36º S, were examined for food contents and parasite infracommunities. Food items were encountered in almost 70 % of fish examined with 25 prey items being recognized. Only one of the prey items was found in both juvenile and adult fish. The diet of juvenile fish consisted mainly of amphipods and while that of adults was mainly composed of crustacean decapods. Almost 40 % of fish examined harbored parasites with a total of 624 individuals and belonging to 16 taxa being identified, four of which were shared between juvenile and adult fish. Prevalence, total intensity, richness, and diversity of parasites was similarly low among juvenile fish sampled at four different localities, while significant differences in total prevalence, dietary and parasite infracommunity composition among localities were found. Absence of a clear relationship among juvenile fish between the composition of the diet and of infracommunities may be due to the fact that parasitoses are necessarily recent. Adult hosts had infracommunities with greater total prevalence

  1. Depositación atmosférica de nitrógeno en un transecto valle longitudinal-cordillera de Los Andes, centro-sur de Chile Atmospheric deposition of nitrogen in a transect from the Central Valley to Cordillera de Los Andes, south-central Chile

    OpenAIRE

    Oyarzún, Carlos E; ROBERTO GODOY; SERGIO LEIVA

    2002-01-01

    El aumento de las actividades agrícolas y ganaderas en el centro-sur de Chile puede producir elevadas emisiones de nitrógeno hacia la atmósfera (mayormente NH3). El amoniaco es transportado por corrientes de aire y depositado en el suelo y vegetación. El presente estudio evalúa la depositación atmosférica de compuestos nitrogenados (NO3- y NH4+) en la química de las precipitaciones en un transecto altitudinal de 66 km, desde los alrededores de la ciudad de Osorno (40º 35' S, 72º 57' O, 55 m d...

  2. Southern Hemisphere circulation signals in connection with winter rainfall forecasting in central Chile

    International Nuclear Information System (INIS)

    The possibility of detecting easterly propagating low frequency signals in the Southern Hemispheric circulation is explored in connection with the assessment of a possible seasonal rainfall forecast in central Chile. The analysis has focused on the seasonal variability associated with the biennial component of the Southern Oscillation (SO) and on the one resulting from superimposed intraseasonal oscillations, in relation with winter precipitation and individual rainfall events, respectively. Based on a previous work, relating wet winters to frequent blocks to the SW of South America during warm events of the SO, time-longitude cross sections of a 5-day average blocking index (BI) calculated from ECMWF 200 hPa daily hemispheric analyses for the period 1980-1987 are presented. A general eastward displacement of western and central Pacific positive BI areas seems to characterize the developing phase of warm SO events and vice versa, while intraseasonal variability patterns appear to be related to single rainstorms, either when the positive BI phase of the wave amplifies while crossing the western Pacific or when it reaches the far southeastern Pacific, frequently with a double block structure. It is concluded that the behaviour of both sources of variability is consistent with previously described teleconnection patterns for ENSO events in the southern winter, and that a primary prospect for winter precipitation and for the occurrence of relatively large individual rainstorms in central Chile could be obtained following the filtered BI and 500 hPa height anomalies in both time scales during the fall season. (author). 28 refs, 12 figs

  3. First radiometric age (U-Pb, LA-ICP-MS, on detrital zircons) from the Punta Topocalma Formation: insights on Late Cretaceous marine deposition in central Chile

    International Nuclear Information System (INIS)

    Upper Cretaceous marine rocks crop out along the Pacific coast of central and south-central Chile between 33o and 37oS. These strata constitute an important reference for the Upper Cretaceous of South America due to their diverse fossil fauna and flora. The type unit of these deposits is the Quiriquina Formation, near Concepcion. This unit is considered Maastrichtian in age based on ammonites. Upper Cretaceous marine strata from other localities of central and south-central Chile are largely unstudied and their biostratigraphic ages are not precisely known. We present the first radiometric dating (U-Pb on detrital zircons) for Upper Cretaceous marine strata of the Chilean forearc at Punta Topocalma that indicates a probable depositional age of 71.9+0.9 Ma (latest Campanian-earliest Maastrichtian). Provenance analysis indicates that the source of sediments of the Punta Topocalma Formation was plutonic and volcano-sedimentary rocks from the Coastal Cordillera and the Central Depression of central Chile. The Lo Valle Formation, a volcano-sedimentary unit in the Central Depression, recorded deposition of the Upper Cretaceous volcanic arc that was coeval with marine sedimentation in the Topocalma area

  4. EL ESTADO ACTUAL DEL HUEMUL (HIPPOCAMELUS BISULCUS EN CHILE CENTRAL CURRENT STATUS OF THE HUEMUL (HIPPOCAMELUS BISULCUS IN CENTRAL CHILE

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    Anthony Povilitis

    2002-01-01

    Full Text Available La única población sobreviviente del huemul en Chile central (Los Nevados de Chillán se encuentra en un descenso clásico hacia la extinción. Se utilizan los datos de prospecciones en terreno por el período entre 1975 a 2002 para estimar el tamaño, la estructura espacial y la tendencia de la población. Un análisis de la población en 1997 arrojó un mínimo de 60 huemules en 12 sitios, y una declinación de un 58% en la población durante un período de dos décadas. Prospecciones recientes entre 1998-2002 indican que la población de huemules ha continuado disminuyendo a 40 individuos en 11 sitios, lo que representa un descenso adicional de un 33%. Desde el año 1987, los huemules han desaparecido de 5, y posiblemente 8, sitios de hábitat primario. Solamente un sitio, el del Río Niblinto que es protegido, muestra un grupo del huemul más o menos estable. Las amenazas al huemul y a su hábitat, tal como los impactos del ganado doméstico, la urbanización, el desarrollo recreativo, la presencia de perros domésticos y las actividades industriales siguen sin disminución en la gran mayoría de los 26 sitios de hábitat primario necesario para la recuperación del huemul. Los datos actuales muestran claramente que una compaña de conservación más amplia es necesaria para resguardar y recuperar la especie en Chile central. Se requieren proteger los sitios de hábitat primario y los corredores conectantes de hábitat del huemul. Para realizar tal objetivo, se necesitan un fuerte compromiso e inversión financiera del gobierno y del sector privado. La creación de un nuevo parque nacional o gran reserva para el huemul y la biodiversidad en el sector de Los Nevados de Chillán, con beneficios relacionados al turismo, la educación pública, e investigaciones científicas, podría ayudar a atraer los recursos financieros que se necesitan para un programa exitoso de conservaciónABSTRACT The only surviving population of huemul in central

  5. Selenium concentration in compartments of aquatic ecosystems in Central Chile

    Energy Technology Data Exchange (ETDEWEB)

    Pinochet, H.; Gregori, I. de; Cavieres, M.F. [Catholic University of Valparaiso, Valparaiso (Chile). Chemical Institute

    2002-07-01

    A study was conducted during 1995-96 to evaluate Se concentration in water, sediment, and plants from aquatic ecosystems of central Chile, an area particularly affected by mining activities. Samples were collected from Panquehue, Chagres, and Ocoa along the Acongua River (presumably receives discharges from a copper refinery and a copper mine). Samples were also collected from one site on the Puchuncavi Stream (directly contaminated by both a coal power plant and a copper refinery). In addition, samples were also collected from one site on the Limache Stream (an urban area with no Se-contaminating sources). The sediment and plant samples collected in Puchuncavi had higher Se levels, which were statistically different to the concentration in samples from other sites. Sediments from Puchuncavi and Ocoa had the highest levels of Se (520 plus or minus 46 and 440 plus or minus 10 {mu} g/kg, respectively) while the plant (Jussiaea repens (Ludwigia repens)) collected in Puchuncavi had an Se concentration 6.5 times higher than the sample collected in Panquehue (116 plus or minus 154 and 182 plus or minus 54 {mu} g/kg, respectively). Puchuncavi water had more acidic pH than water from the other sites thus decreasing Se solubility. Se concentrations in sediment and water collected in Chagres were lower than the concentration determined in sediment and water from either Ocoa or Panquehue. Plant/water and plant/sediment accumulation factors and a sediment/water distribution factor were similar for all sampling sites, except Puchuncavi (accumulation and distribution factors are higher than at the other sites). Hydrocotyle ranunculoides had practically the same plant/sediment accumulation factor at all sites while the accumulation factor for J. repens varied according to site. The samples collected in the Limache stream had Se at equal or even higher concentration than the other samples collected from presumably contaminated sites (except Puchuncavi). 19 refs.

  6. Chile.

    Science.gov (United States)

    1992-05-01

    The background notes on Chile provide a statistical summary of the population, geography, government, and the economy, and more descriptive text on the history, population, government, economy, defense, and foreign relations. In brief, Chile has 13.3 million Spanish Indian (Mestizos), European, and Indian inhabitants and an annual growth rate of 1.6%. 96% are literate. Infant mortality is 18/1000. 34% of the population are involved in industry and commerce, 30% in services, 19% in agriculture and forestry and fishing, 7% in construction, and 2% in mining. The major city is Santiago. The government, which gained independence in 1810, is a republic with executive, legislative, and judicial branches. There are 12 regions. There are 6 major political parties. Suffrage is universal at 18 years. Gross domestic product (GDP) is $29.2 billion. The annual growth rate is 5% and inflation is 19%. Copper, timber, fish, iron ore, nitrates, precious metals, and molybdenum are its natural resources. Agricultural products are 9% of GDP and include wheat, potatoes, corn, sugar beets, onions, beans, fruits, and livestock. Industry is 21% of GDP and includes mineral refining, metal manufacturing, food and fish processing, paper and wood products, and finished textiles. $8.3 billion is the value of exports and $7 billion of imports. Export markets are in Japan, the US, Germany, Brazil, and the United Kingdom. Chile received $3.5 billion in economic aid between 1949-85, but little in recent years. 83% live in urban centers, principally around Santiago. Congressional representation is made on the basis of elections by a unique binomial majority system. Principal government officials are identified. Chile has a diversified free market economy and is almost self-sufficient in food production. The US is a primary trading partner. 49% of Chile's exports are minerals. Chile maintains diplomatic relations with 70 countries, however, relations are strained with Argentina and Bolivia. Relations

  7. Patrones de regeneración arbórea en claros a una década de la floración y muerte masiva de Chusquea quila (Poaceae en un remanente de bosque antiguo del valle central en el centro-sur de Chile Tree regeneration patterns in canopy gaps after a decade of Chusquea quila (Poaceae dieback in an old-growth remnant forest in the lake district of south-central Chile

    Directory of Open Access Journals (Sweden)

    ARIEL A MUÑOZ

    2009-06-01

    óreas tolerantes y semitolerantes, especialmente a aquellas de exitosa reproducción vegetativa. Especies pioneras en estos bosques como N. obliqua no fueron favorecidas por esta alteración endógena en claros pequeños (In old-growth forests at low elevations in south-central of Chile (38-42° S, the native understory bamboo Chusquea quila plays an important role on the establishment and growth of tree species in tree-fall gaps. Bamboo dieback that occurs after an extensive vegetative period represents a large-scale endogenous disturbance that could influence tree regeneration dynamics in gaps. The main goal of this study was to analyze the main patterns of the tree regeneration in canopy gaps in an old-growth remnant forest, 10 years after the bamboo dieback in 1994. Six gaps tree-fall gaps were located and permanent plots were established to study the demography and growth changes of the advanced regeneration and new recruitments. These changes were evaluated between the years 1994 and 2003. The advanced regeneration was composed mainly of the shade-tolerant tree species A. punctatum, L. philippiana and A. luma. Their mortality after 10 years averaged 42 % and affected mostly individuals originated from seeds. In contrast, individuals of L. philippiana and E. cordifolia, originated from rootstocks, showed higher growth rates and lower mortality. On the other hand, new recruitment was characterized by the abundant regeneration of N. obliqua, P. saligna and A. chilensis during the first season after the dieback; however few individuals of these species survived the competition of the new bamboo cohort. Similarly, juveniles originated from rootstocks of E. cordifolia, G. avellana and L. philippiana showed higher growth rates and survivorship than plants originated from seeds. These results suggest that the temporary increase of resources in canopy gaps, due to the bamboo dieback, would favor tree species of mid-late successional stands, especially those originated from vegetative

  8. Litterfall, litter decomposition and nitrogen mineralization in old-growth evergreen and secondary deciduous Nothofagus forests in south-central Chile Aporte, descomposición de hojarasca y mineralización de nitrógeno en bosques siempreverdes de antiguo crecimiento y bosques secundarios deciduos, centro-sur de Chile

    Directory of Open Access Journals (Sweden)

    JEROEN STAELENS

    2011-03-01

    Full Text Available South Chilean forest ecosystems represent one of the largest areas of old-growth temperate rainforests remaining in the Southern hemisphere and have a high ecological value, but suffer from deforestation, invasion by exotic species, fragmentation, and increasing atmospheric nitrogen (N deposition. To support sustainable forest management, more knowledge is required on nutrient cycling of these ecosystems. Therefore, a descriptive study of nutrient dynamics was done in four Valdivian rainforests in the lower Andes range of south Chile: old-growth and altered evergreen stands and unmanaged and managed secondary deciduous stands. Time series were measured for (i mass (four year and nutrient content (N, K, Ca, and Mg; one year of litterfall, (ii decomposition and nutrient dynamics (N, C, K, Ca, Mg, and P; one year of leaf litter and Saxegothaea conspicua bark litter, and (iii in situ topsoil net N mineralization (one year. Litterfall in the four stands ranged from 3.5 to 5.8 ton ha-1 yr-1, was temporarily lower in the managed than in the unmanaged deciduous stand and had a different seasonality in the evergreen stands than in the deciduous stands. Leaf litter decomposed faster (on average 32 % mass loss after one year than bark litter (8 % but without significant differences between leaf litter types. Net N in evergreen leaf litter decreased during decomposition but increased in deciduous leaf litter. Net soil N mineralization was fastest in the pristine evergreen stand, intermediate in the deciduous stands and slowest in the altered evergreen forest. Given the absence of replicated stands, the definite impact of forest type or management regime on the internal nutrient cycling cannot be demonstrated. Nevertheless, the results suggest that management can affect nutrient turnover by altering species composition and forest structure, while recent (five years selective logging in secondary deciduous forest did not affect litter decomposition or N

  9. Chile.

    Science.gov (United States)

    1986-04-01

    In 1985, Chile's population stood at 12 million, with an annual growth rate of 1.7%. 1984's infant mortality rate was 20/1000 live births and life expectancy was 67 years. The literacy rate was 94%. Of the work force of 3,841,000 in 1985, 15.9% were engaged in agriculture, forestry, and fishing; 31.3% were employed in industry and commerce; 38.6% were in the service sector; 8.7% worked in mining; and 4.4% were employed in construction. Chile's military junta is scheduled to be replaced by an elected legislature in 1990. The GDP was US $19.2 billion in 1984, with an annual real growth rate of 6.3%, and per capita GDP stood at US$1590. Inflation averages 23%. Industry comprises 21% of the GDP. Longterm prospects for the Chilean economy are influenced by a high debt service ratio, very low domestic savings and investment, the prospect of little or no increase in copper prices, and continuing problems in the domestic financial sector. In 1985-88, under the International Monetary Fund macroeconomic program, Chile will strive for moderate economic growth while managing its external debt servicing burden. PMID:12178144

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

    Science.gov (United States)

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

    2015-01-01

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

  11. Chanco formation, a potential Cretaceous reservoir, central Chile

    Energy Technology Data Exchange (ETDEWEB)

    Cecione, G.

    1983-07-01

    The Chanco embayment lies 300 km SSW of Santiago, Chile. The sequence within this basin above the metamorphic basement is: Chanco Formation (very clean sandstone), Quiriquina Formation (glauconitic sandstone, rich in organic matter), and Navidad Group (a very good caprock). This section thus contains reservoir, source and caprocks, and is therefore very promising for petroleum investigations. The offshore C-1 well yielded salt-water with gas shows, and two wells drilled onshore yielded shows of gas. The C-1 well lies on a gently-dipping EW-striking anticlinal structure, the presence of which makes the area very prospective.

  12. Paleoenvironmental change in central Chile as inferred from OSL dating of ancient coastal sand dunes

    Science.gov (United States)

    Andrade, Belisario; Garcia, Juan L.; Lüthgens, Christopher; Fiebig, Markus

    2013-04-01

    To present day, the climatic and geographic expression of glacials and interglacials in the semiarid coast of central Chile remains unclear. The lack of well dated paleoclimatic records has up to now precluded firm conclusions whether maximum glacials evident in the Andes mountain range probably coincide with wetter (e.g., pluvials) or drier conditions at the coast. The natural region locally known as "Norte Chico" represents a transitional semiarid area between the extreme Atacama Desert to the North and the wetter, Mediterranean-like type of climate, to the South. In this semiarid region of Chile several generations of eolian sand dunes, some of them separated by paleosoils, have been preserved. In addition to the occurrence of paleosoils, thick debris flow deposits in some places overly ancient dune bodies, likely indicating significant environmental changes during the formation of these archives. However, the exact timing of these processes within the mid to late Pleistocene and Holocene is still unclear. A key aspect is that some of the ancient dunes are recently hanging above rocky coastlines, where no supply of sand exists today, likely implying their formation during a lower than present, probably glacio-eustatically induced sea level. The location of the research area in a key mid-latitude region of the eastern Pacific in combination with the preserved landform record offers a chance to reconstruct climatic shifts during the Quaternary by studying the variability of morphogenetic conditions throughout time, in order to promote knowledge about possible forcing factors driving climatic variability. Within this pilot study, samples for optically stimulated luminescence (OSL) dating were taken from three different stratigraphic sections that denote a complex environmental variability as indicated by paleosoils and debris flow units intercalated in ancient sand dunes. First dating results inferred from OSL measurements using a post-IR IRSL (pIRIR) protocol for

  13. Análisis de las tasas de captura de jurel (Trachurus symmetricus) en la zona centro-sur de Chile (1987-1999) Jack mackerel (Trachurus symmetricus) catch rate analysis in the central-south of Chile (1987-1999)

    OpenAIRE

    Claudio Gatica; Luis Cubillos

    2002-01-01

    Se analizaron los cambios en la Captura por Unidad de Esfuerzo (CPUE) de la pesquería industrial de cerco de jurel (Trachurus symmetricus) en la zona centro-sur de Chile entre 1987 y 1999. Se utilizaron dos unidades de esfuerzo de pesca para calcular las tasas de captura: días fuera de puerto y viajes con pesca. La flota se clasificó en cuatro estratos homogéneos mediante Análisis de Componentes Principales (ACP), utilizando una matriz de correlación de variables técnico-operacionales. Los do...

  14. Cambio del uso del suelo en el centro sur de Chile a fines del siglo XX: Entendiendo la dinámica espacial y temporal del paisaje Land use change in the south central Chile at the end of the 20th century: Understanding the spatio-temporal dynamics of the landscape

    OpenAIRE

    MAURICIO AGUAYO; ANÍBAL PAUCHARD; GERARDO AZÓCAR; OSCAR PARRA

    2009-01-01

    Los humanos han transformado gran parte de la superficie del planeta en los últimos 300 años. La tala de bosques, las prácticas agrícolas de subsistencia, la intensificación de la producción agrícola y la expansión de los centros urbanos han cambiado drásticamente el paisaje. En el centro y sur de Chile las transformaciones han estado asociadas, en un inicio, a la expansión de la frontera agropecuaria que permitió satisfacer tanto las necesidades internas como la creciente demanda externa por...

  15. Osseous skeletal material and fish scales in marine sediments under the oxygen minimum zone off northern and central Chile

    Science.gov (United States)

    Milessi, Andrés C.; Sellanes, Javier; Gallardo, Víctor A.; Lange, Carina B.

    2005-08-01

    The significance of whale falls for the study of the biogeography, evolution and biodiversity of deep-sea biota has been recently recognized by international programs since large carcasses are known to give rise to biogenic chemosynthetic ecosystems. However, the plain accumulation of smaller bone material in the shallower settings of the continental shelf and upper slope under the hypoxic conditions of the Oxygen Minimum Zone (OMZ), has received much less attention. Here we describe new findings of skeletal material and fish scales in marine sediments under the OMZ off northern and central Chile which, combined with previous reports for the study area, lead us to suggest the existence of a band in the benthos of accumulation of bones and scales extending at least twenty degrees in latitude (18-38° S). Future studies should focus on the characterization of biotic communities living upon these resources in order to elucidate their peculiarities and importance in the Eastern South Pacific.

  16. Monitoring land cover change of the dryland forest landscape of Central Chile (1975–2008)

    OpenAIRE

    Rey Benayas, José María; Schulz, Jennifer J.; Cayuela Delgado, Luis; Echeverría, Cristian; Salas Rey, Francisco Javier

    2010-01-01

    Las figuras que contiene el documento se localizan al final del mismo. Land cover and its configuration in the landscape are crucial components in the provision of biodiversity and ecosystem services. In Mediterranean regions, natural landscapes mostly covered by evergreen vegetation have been to a large extent transformed into cultural landscapes since long time ago. We investigated land cover changes in Central Chile using multi-temporal satellite imagery taken in 1975, 1985, 1999 and 20...

  17. Polygenetic development and paleoenvironmental implications of a Pleistocene calcrete at Tongoy, central northern Chile.

    OpenAIRE

    M. Pfeiffer; J. Le Roux; H. Kemnitz

    2011-01-01

    The Norte Chico Region, in central northern Chile, is a particularly sensitive area to Quaternary climate changes because of its extreme climatic gradients. However, very little has been done to determine the late Pleistocene climatic conditions of the area. Calcretes are known to be important repositories of information on past ecosystems and environments. In the Tongoy paleobay, a series of four marine beach terraces have developed over a Mio-Pliocene calcareous formation since MIS 11 to th...

  18. Direct measurement and prediction of bulk density on alluvial soils of central Chile

    OpenAIRE

    Manuel Casanova; Elizabeth Tapia; Oscar Seguel; Osvaldo Salazar

    2016-01-01

    The significance of soil bulk density (ρ) as a key indicator of soil quality was examined in this study. Bulk density values obtained by direct methods (clod, cylinder, and excavation) with three sample sizes (small, medium, and large) were compared with those obtained by 10 published pedotransfer functions (PTFs) for two alluvial soils (a massive fine-textured Fluventic Haploxeroll and an aggregated, coarse-textured Fluventic Haploxerept) of central Chile. With the exception of small cylinde...

  19. Provenance variations in the Late Paleozoic accretionary complex of central Chile as indicated by detrital zircons

    OpenAIRE

    Hervé, F.; Calderón, M.; Fanning, C. M.; Pankhurst, R.J.; Godoy, E.

    2013-01-01

    We present detrital zircon UPb SHRIMP age patterns for the central segment (34–42°S) of an extensive accretionary complex along coastal Chile together with ages for some relevant igneous rocks. The complex consists of a basally accreted high pressure/low temperature Western Series outboard of a frontally accreted Eastern Series that was overprinted by high temperature/low pressure metamorphism. Eleven new SHRIMP detrital zircon age patterns have been obtained for meta-turbidites from the cent...

  20. Occurrence of Campylobacter jejuni and Campylobacter coli and their biotypes in beef and dairy cattle from the south of Chile

    OpenAIRE

    Heriberto Fernández; Marianne Hitschfeld

    2009-01-01

    The prevalence of Campylobacter jejuni and Campylobacter coli and their biotypes in beef and dairy cattle from the South of Chile was established. Campylobacter were statistically more prevalent among beef cattle (35.9%) than among dairy cattle (21.3%), being C. jejuni the species most frequently isolated.Foi estabelecida a prevalência de Campylobacter jejuni e Campylobacter coli e seus biotipos, em bovinos de corte e de leite do sul do Chile. Campylobacter foi estatisticamente mais prevalent...

  1. First pathological report of parasitic gastric ulceration in Humboldt penguin(Spheniscus humboldtialong the coast of south-central Chile Primera descripción patológica de úlceras gástricas parasitarias en el pingüino de Humboldt (Spheniscus humboldti en la costa centro-sur de Chile

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    Francisco Yáñez

    2012-07-01

    Full Text Available This report offers a macroscopic and histological description of ulcerative gastric lesions in Humboldt penguins associated with the presence of Contracaecum pelagicum. Parasites of this genus have been isolated from different species of marine mammals and birds, including penguins, demonstrating its capacity to generate ulcerative lesions in the gastrointestinal tracts of many hosts. A bibliographic review revealed no publications on gastric ulceration by nematodes in Humboldt penguins. Studies carried out in Chile concerning gastrointestinal parasitism by nematodes of the Contracaecum genus in S. humboldti only established the parasite's taxonomy. This is the first pathological description of a parasitic ulcerative manifestation in the stomach of S. humboldti in the world. The Humboldt penguin is a vulnerable species. Therefore, this study is relevant as it offers a better understanding of the diseases that affect S. humboldti and facilitates the development of strategies intended to recover the population.El presente trabajo ofrece una descripción macroscópica e histológica de lesiones gástricas de tipo ulcerativas en el pingüino de Humboldt asociadas a la presencia de Contracaecum pelagicum. Parásitos del género Contracaecum han sido aislados de diferentes especies de mamíferos y aves marinas, incluyendo pingüinos, en gran parte del mundo, demostrando una gran capacidad de generar lesiones ulcerativas en un número importante de hospederos. La revisión bibliográfica reveló la ausencia de publicaciones relativas a cuadros ulcerativos gástricos causados por nemátodos en el pingüino de Humboldt. Los estudios realizados en Chile concernientes a parasitismo gastrointestinal por nemátodos del género Contracaecum en S. humboldti sólo han abordado aspectos taxonómicos. Esta publicación constituye la primera descripción patológica de un cuadro de ulceraciones gástricas parasitarias en el pingüino de Humboldt. S. humboldti est

  2. Impact of Intrathermocline eddies on seamount and oceanic island off Central Chile: Observation and modeling

    Science.gov (United States)

    Hormazabal, Samuel; Morales, Carmen; Cornejo, Marcela; Bento, Joaquim; Valencia, Luis; Auger, Pierre; Rodriguez, Angel; Correa, Marco; Anabalón, Valeria; Silva, Nelson

    2016-04-01

    In the Southeast Pacific, oceanographic processes that sustain the biological production necessary to maintain the ecosystems associated to seamounts and oceanic islands are still poorly understood. Recent studies suggest that the interaction of mesoscale and submesoescale eddies with oceanic islands and seamounts could be playing an important role in the time-space variability of primary production. In this work, research cruises, satellite data and Regional Ocean Modeling System (ROMS) results have been used to describe the main characteristics of intrathermocline eddies (ITE) and their impact on the Juan Fernández archipelago (JFA), off central Chile. The JFA is located off the coast of central Chile (33°S), and is composed of three main islands: Robinson Crusoe (RC), Alejandro Selkirk (AS) and Santa Clara (SC). Between the RC and AS are located the westernmost seamounts (JF6 and JF5) of the Juan Fernández archipelago. Satellite altimetry data (sea surface height from AVISO) were used to detect and track mesoscale eddies through eddy-tracking algorithm. Physical, chemical and biological parameters as temperature, salinity, dissolved oxygen and fluorescence were measured in the water column at JF5 and JF6, and along the coast off central Chile (30-40°S). Results from the research cruise exhibit the interaction between an ITE and the seamount JF6. Eddy-tracking results showed that the ITE observed at the JF6 was formed at the coast off central-southern Chile, traveled ~900 km seaward and after ~9 months reached the JF5 and JF6 region. Observations along the Chilean coast confirmed that the coast corresponds to the formation area of the observed ITE. In this region, ITEs are represented by subsurface lenses (~100 km diameter; 400 m thickness) of homogeneous salinity, nutrient rich and oxygen-poor equatorial subsurface water mass (ESSW) which is transported poleward by the Peru-Chile undercurrent in the coastal band and seaward by ITEs. The effect of ITEs on the

  3. MEJORAMIENTO DE TRIGOS HARINEROS (Triticum aestivum L. EN LA ZONA CENTRO SUR DE CHILE.: ANALISIS DEL RENDIMIENTO Y VARIABLES ASOCIADAS EN TRIGOS DE PRIMAVERA Genetic improvement in bread wheats (Triticum aestivum L. in the South Central area of Chile.: Analysis of grain yield and related variables in spring varieties

    Directory of Open Access Journals (Sweden)

    Mario Mellado Z.

    2000-01-01

    Full Text Available Se realizaron experimentos de campo con once variedades de trigos (Triticum aestivum L. de primavera liberadas a la producción comercial entre 1971 y 1993, para evaluar la ganancia genética en rendimiento de grano y sus variables asociadas (biomasa, índice de cosecha, granos por espiga, peso de mil semillas y peso del hectolitro. Los genotipos fueron desarrollados en el Proyecto de Mejoramiento de Trigo del Centro Regional de Investigación Quilamapu, del Instituto de Investigaciones Agropecuarias. Mexifén fue la primera variedad de este grupo, y se usó como variedad de referencia. Los experimentos se llevaron a cabo en Chillán, Chile, durante 1995 a 1998. En cada año se realizaron dos experimentos similares, con y sin control de enfermedades foliares, para evaluar la ganancia genética y el daño de las enfermedades respectivamente. El promedio de rendimiento de todas las variedades, durante los cuatro años, con fungicida fue de 9,02 t ha-1 y de 7,50 t ha-1 sin fungicida. No se detectó ganancia genética significativa en rendimiento de grano, ni en sus variables asociadas, con la excepción del peso de la semilla. En este último caso la ganancia genética fue de 22,1 mg grano-1 año-1. Se concluyó que las variedades distribuidas entre 1971 y 1993, no mostraron ganancia genética en rendimiento de grano y, que la razón principal para el cambio de variedades en ese período habría sido la resistencia genética a las enfermedades foliares.Field experiments with eleven spring wheat varieties released between 1971 and 1993 were carried out to assess genetic gain in yield potential and related variables (biomass, harvest index, kernels/spike, kernel weight and test weight. The genotypes tested were developed in the Quilamapu Wheat Breeding Program. Mexifén was the first enhanced variety of this group, and was used as the standard variety. The experiments were carried out at the Instituto de Investigaciones Agropecuarias, Chillán, Chile

  4. MEJORAMIENTO DE TRIGOS HARINEROS (Triticum aestivum L. EN LA ZONA CENTRO SUR DE CHILE: CONTENIDO Y PRODUCCIÓN DE PROTEINA, Y VOLUMEN DE SEDIMENTACIÓN EN TRIGOS INVERNALES, ALTERNATIVOS Y PRIMAVERALES Genetic improvement of bread wheat (Triticum aestivum L. in the South Central zone of Chile: Protein content, production and sedimentation volume of winter, alternative and spring wheats

    Directory of Open Access Journals (Sweden)

    Mario Mellado Z.

    2001-04-01

    Full Text Available Se realizaron cuatro experimentos de campo con diez variedades de trigos de invierno y hábito alternativo (grupo 1, y cuatro experimentos con once variedades de trigos de primavera (grupo 2, para evaluar el porcentaje y producción de proteína del grano, y el volumen de sedimentación. Los genotipos fueron desarrollados en el Proyecto de Mejoramiento de Trigo del Instituto de Investigaciones Agropecuarias (INIA, Centro Regional de Investigación Quilamapu. Lilifén fue la primera variedad mejorada en el grupo 1, y Mexifén en el grupo 2; por lo tanto ambas fueron usadas como referencia. Los experimentos se llevaron a cabo en suelos Andisoles del Campo Experimental Santa Rosa (INIA, Chillán, Chile, desde el año 1995 a 1998. Los porcentajes medios de proteína de las variedades de los grupos 1 y 2 fueron 9,6 %, y 10,8%, respectivamente. El promedio de producción de proteína de las variedades del grupo 1 fue 894,6 kg ha-1 mientras que en el grupo 2 este valor fue 968,4 kg ha-1. Los valores medios para sedimentación fueron 3,4 mL en el grupo 1 y 4,3 mL en el grupo 2. En relación a las variedades, los resultados demostraron que el trabajo de mejoramiento de trigo realizado entre 1968 y 1993 fue más exitoso en mejorar el contenido de proteína del grano que su calidadFour field experiments with ten winter and alternative varieties (group 1 and four experiments with eleven spring wheat varieties (group 2, were carried out to assess grain protein percentage, grain production and sedimentation volume. The tested genotypes were developed at the Quilamapu Wheat Breeding Program, Institute of Agricultural Research, INIA. Lilifen was the first breed variety improved in group 1, and Mexifen in group 2; as such both were used as references. The experiments were carried out in Andisoil soils at the Santa Rosa Experimental Field, Chillán, Chile, from 1995 to 1998. The mean protein percentage of varieties of groups 1 and 2 were 9.6 and 10

  5. Litterfall, litter decomposition and nitrogen mineralization in old-growth evergreen and secondary deciduous Nothofagus forests in south-central Chile Aporte, descomposición de hojarasca y mineralización de nitrógeno en bosques siempreverdes de antiguo crecimiento y bosques secundarios deciduos, centro-sur de Chile

    OpenAIRE

    JEROEN STAELENS; NELE AMELOOT; LEONARDO ALMONACID; EVELYN PADILLA; PASCAL BOECKX; DRIES HUYGENS; KRIS VERHEYEN; CARLOS OYARZÚN; ROBERTO GODOY

    2011-01-01

    South Chilean forest ecosystems represent one of the largest areas of old-growth temperate rainforests remaining in the Southern hemisphere and have a high ecological value, but suffer from deforestation, invasion by exotic species, fragmentation, and increasing atmospheric nitrogen (N) deposition. To support sustainable forest management, more knowledge is required on nutrient cycling of these ecosystems. Therefore, a descriptive study of nutrient dynamics was done in four Valdivian rainfore...

  6. Patrones de regeneración arbórea en claros a una década de la floración y muerte masiva de Chusquea quila (Poaceae) en un remanente de bosque antiguo del valle central en el centro-sur de Chile Tree regeneration patterns in canopy gaps after a decade of Chusquea quila (Poaceae) dieback in an old-growth remnant forest in the lake district of south-central Chile

    OpenAIRE

    ARIEL A MUÑOZ; MAURO E GONZÁLEZ

    2009-01-01

    En bosques de elevaciones bajas del centro-sur de Chile (38-42° S) Chusquea quila (Poaceae) es la especie del sotobosque de mayor influencia en el proceso de regeneración de especies arbóreas en claros naturales y antropogénicos. Su floración y muerte sincrónica, después de un extenso periodo en estado vegetativo, constituye una alteración de gran escala que puede afectar importantemente la dinámica de regeneración arbórea en claros. El último episodio de muerte masiva de C. quila (1989-1995)...

  7. Depositional environment of Stelloglyphus llicoensis isp. nov.: a new radial trace fossil from the Neogene Ranquil Formation, south-central Chile Ambiente depositacional de Stelloglyphus llicoensis isp. nov.: una nueva traza fósil radial de la Formación Ranquil (Neógena), centro-sur de Chile

    OpenAIRE

    Le Roux, Jacobus P.; Nielsen, Sven N; Álvaro Henríquez

    2008-01-01

    Stelloglyphus llicoensis isp. nov. is a large radial, discoidal to ellipsoidal trace fossil with a central shaft and single to bifurcating branches radiating from different levels. A 30 m thick measured section of the Ranquil Formation at Punta Litre contains an associated trace fossil assemblage including Zoophycos, Chondrites, Phycosiphon, Nereites missouriensis, Lockeia siliquaria, Psammichnites(?), Parataenidium,Ophiomorpha,and Rhizocorallium,some of which reworked the Stelloglyphus trace...

  8. Latitudinal discontinuity in thermal conditions along the nearshore of central-northern Chile.

    Science.gov (United States)

    Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A

    2014-01-01

    Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

  9. Tropical/subtropical Upper Paleocene Lower Eocene fluvial deposits in eastern central Patagonia, Chile (46°45'S)

    Science.gov (United States)

    Suárez, M.; de la Cruz, R.; Troncoso, A.

    2000-11-01

    A succession of quartz-rich fluvial sandstones and siltstones derived from a mainly rhyolitic source and minor metamorphic rocks, located to the west, represent the first Upper Paleocene-Early Eocene deposits described in Chilean eastern central Patagonian Cordillera (46°45'S). This unit, exposed 25 km south of Chile Chico, south of lago General Carrera, is here defined as the Ligorio Márquez Formation. It overlies with an angular unconformity Lower Cretaceous shallow marine sedimentary rocks (Cerro Colorado Formation) and subaerial tuffs that have yielded K-Ar dates of 128, 125 and 123 Ma (Flamencos Tuffs, of the Divisadero Group). The Ligorio Márquez Formation includes flora indicative of a tropical/subtropical climate, and its deposition took place during the initial part of the Late Paleocene-Early Eocene Cenozoic optimum. The underlying Lower Cretaceous units exhibit folding and faulting, implying a pre-Paleocene-Lower Eocene contractional tectonism. Overlying Oligocene-Miocene marine and continental facies in the same area exhibit thrusts and normal faults indicative of post-Lower Miocene contractional tectonism.

  10. Las comunidades relictas de Gomortega keule (Gomortegaceae, Magnoliopsida en Chile central

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    Sánchez Álvarez, Ana

    1999-12-01

    Full Text Available Some inventories were made in fourteen localities of Chilean températe forest with presence of Gomortega keule. All of them are situated on the west side of the Coastal Range in Central Chile. This species, the only member of the Gomortegaceae and an endemic to this área of Chile, is endangered because of habitat occupation by plantations of exotic species. In this paper, the floristic composition and ecology of these communities are described. The information about the distribution of this species is also updated.Se caracterizan florísticamente las comunidades de Gomortega keule existentes en la ladera occidental de la Cordillera de la Costa de Chile central. La riqueza florística de estas comunidades es muy elevada, con un total de 106 especies para las 14 localidades inventariadas, distribuidas en 56 familias y 83 géneros. La clara dominancia de fanerófitos (78,3%, y dentro de éstos la distribución de las distintas formas de crecimiento (17% de trepadoras y 3,8% de epífitos, condiciona tanto estructural como fisionómicamente a estas comunidades. El grupo de especies propias del bosque valdiviano es el más abundante, 42,5% de las especies, seguido de las de carácter esclerófilo típicas del Valle Central (14,2%. La conservación de G. keule, única especie de la familia Gomortegaceae, está completamente ligada al mantenimiento de estas comunidades, que en la actualidad están siendo sustituidas sistemáticamente por plantaciones forestales de especies exóticas en toda su área de distribución.

  11. A new species of Phymaturus (Iguania: Liolaemidae) of the palluma group from Central Chile

    OpenAIRE

    Troncoso-Palacios, Jaime; Lobo, Fernando

    2012-01-01

    We examined specimens of Phymaturus from four locations in central Chile, between 34º50´S and 36º00´S (from Termas del Flaco and from Lircay and its surroundings), where the only recognized species is P. maulense. We found several differences in the scalation and in the color pattern among them. The samples from Lircay and its surroundings correspond to topotypes of P. maulense and two more populations assignable to this species (Termas del Campanario and Laguna del Maule, new records), but t...

  12. Mineralización del nitrógeno, carbono y actividad enzimática del suelo en un bosque de Nothofagus obliqua (Mirb Oerst y una plantación de Pinus radiata D. Don. del centro-sur de Chile Nitrogen and carbon mineralization and enzyme activity in soils of Nothofagus obliqua (Mirb Oerst stands and Pinus radiata D. Don plantation in south-central Chile

    Directory of Open Access Journals (Sweden)

    YESSICA RIVAS

    2009-03-01

    Nothofagus obliqua (Mirb Oerst forest and P. radiata plantation in central-southern Chile (40°07' S, 72° W. In this study, the rate of nitrogen mineralization (N-min, carbon mineralization (C-min and the potential enzymatic activity of soils (urease, protease and fluorecein diacetate hydrolysis were determined between September 2003 and May 2005. Results showed that soil biological activity was significantly different between forest and plantations (Wilk's Lambda = 0.022; F> 5,80 = 733, P < 0,0001, and among the months (Wilk's Lambda = 0.01 E-6, F100,395 = 84, P < 0,0001, with vaiues for N. obliqua forest significantly higher (Tukey < 0.01 than those for P. radiata plantation. N-min and C-min rates showed seasonal variability with the higher values in spring and summer months. For enzymatic activity there was not a clear seasonal variation. The higher values of C and N-min and enzymatic activity in the N. obliqua forest could be explained by differences in composition and chemistry of litter. Consequently, P. radiata plantation changed soil chemistry and C/N ratio resulting in lower decomposition rates of organic matter and in consequence, reduced mineralization of C and N and soil biological activity compared to the original soil of N. obliqua forest.

  13. Relación entre características del hábitat y estructura del ensamble de insectos en humedales palustres urbanos del centro-sur de Chile Relationship between habitat characteristics and insect assemblage structure in urban freshwater marshes from central-south Chile

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    ROMINA VILLAGRÁN-MELLA

    2006-06-01

    Full Text Available Los humedales son ecosistemas altamente productivos que se caracterizan por cumplir múltiples funciones, manteniendo además una alta diversidad biológica. No obstante, casi la mitad de los humedales en el mundo ha desaparecido en el último siglo debido al proceso de desarrollo urbano. En Chile, la diversidad bioclimática genera una gran variedad de ambientes acuáticos. Estos ecosistemas también han sido expuestos a fuertes presiones antrópicas, debido al proceso de urbanización. En la intercomuna Concepción-Talcahuano-San Pedro (Región del Biobío más del 23 % (1.734 ha del área ocupada por humedales se ha perdido en las últimas tres décadas. Evaluamos la relación entre características del hábitat (morfométricas, limnológicas y vegetacionales y la estructura del ensamble de insectos en siete humedales palustres de la intercomuna, con el fin de determinar los efectos de la urbanización sobre los patrones de diversidad en estos ecosistemas. Los análisis mostraron que la abundancia relativa y la diversidad de especies se relacionan positivamente con la naturalidad de la matriz y el contenido de oxígeno en el agua, esta última característica fue el predictor más importante para la estructura del ensamble de insectos. De las 24 morfoespecies de insectos analizadas, la abundancia de siete especies fue relacionada significativamente con las características del hábitat consideradas. La naturalidad de la matriz, el área del humedal, la heterogeneidad vegetacional y la concentración de oxígeno disuelto se relacionaron positivamente con la abundancia de estas especies, mientras que la conductividad y/o turbidez del agua mostró un efecto negativo sobre ella. La disminución de la diversidad de insectos determinada por características del hábitat asociadas con la pérdida, fragmentación, homogeneización, eutroficación y/o contaminación de los humedales indica que los insectos podrían ser utilizados como indicadores de

  14. Notice Soliciting Subscription to Journal of Central South University

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Jnurnal of Cenntral South University(CN 43一1516/TB, ISSN 2095-2899) (formerly named Journal of Central South University Technology,CN 43-1231/TD, ISSN 1005-9784) is a comprehensive academic English journal, administrated

  15. Growth of Stone pine (Pinus pinea L. European provenances in central Chile

    Directory of Open Access Journals (Sweden)

    Loewe_Muñoz V

    2016-08-01

    Full Text Available Pinus pinea is characterized by phenotypic plasticity, tolerance to harsh soils and climates, but low differentiation in growth parameters and low genetic variability. Growth and cone production of six European stone pine provenances (two from Italy, three from Spain and one from Slovenia were analyzed in a field trial experiment established in central Chile. The study evaluated height, diameter at breast height (DBH and crown diameter growth of 147 nineteen-year-old trees per provenance, as well as fruiting variables (i.e., number of cones per tree and cone weight. Survival over the first 7 years was also evaluated. Provenances significantly differed in cone number per tree, cone weight, height and DBH growth, and crown diameter growth. Provenances were grouped according to growth and production variables: one group included the Italian and Slovenian provenances, the second group Andalucía and Sierra Morena (Spain, and the third included Meseta Castellana (Spain. Individual cone production was positively correlated with cone weight and other growth variables. Meseta Castellana provenance showed the highest growth and productivity. Our results provide useful information for the selection of P. pinea provenances to be used in new plantations in central Chile.

  16. Diet in pottery-making societies from Central Chile: The contribution of stable isotope analyses

    International Nuclear Information System (INIS)

    This is the first time that stable carbon, nitrogen and oxygen isotope analyses of human bones and teeth have been used to reconstruct subsistence and settlement patterns of prehispanic ceramic societies from Central Chile. Isotope analyses, unlike the evidence from botanical, faunal and artifactual remains from archaeological sites, and from dental and skeletal pathologies, gave information of which resources were really eaten by each individual during the last years of their life. The human data were evaluated against isotopic values of marine and terrestrial resources from central Chile. These results were interpreted taking into consideration different lines of paleodiet evidence. The main contributions are: empirical evidence of dietary differences according to cultural groups; low dependence on marine foods for most people living on the coast; indirect evidence of mobility strategies that show differences between Early and Late Intermediate societies; increased dependence on maize with time, especially among the Aconcagua people; gender differences in maize consumption for the same Aconcagua groups, men showing the greatest levels of maize intake. The results support some hypotheses, such as the difference in dietary patterns between contemporary Bato and Lolleo groups, contradict others, such as the supposed importance of marine diet for coastal inhabitants, and open new research questions for the future

  17. Inequality and Fiscal Redistribution in Middle Income Countries: Brazil, Chile, Colombia, Indonesia, Mexico, Peru and South Africa

    OpenAIRE

    Nora Lustig

    2015-01-01

    This paper examines the redistributive impact of fiscal policy for Brazil, Chile, Colombia, Indonesia, Mexico, Peru and South Africa using comparable fiscal incidence analysis with data from around 2010. The largest redistributive effect is in South Africa and the smallest in Indonesia. Success in fiscal redistribution is driven primarily by redistributive effort (share of social spending to GDP in each country) and the extent to which transfers/subsidies are targeted to the poor and direct t...

  18. Evidence of proterozoic crust under the coastal Cordillera of Central Chile: Grenville age xenocrystic zircons in cretaceous volcanic rocks

    International Nuclear Information System (INIS)

    In the central Andes, Proterozoic basement rocks outcrop in isolated areas from beneath a Mesozoic and Cenozoic cover in southern Peru, northernmost Chile, Bolivia, and in northwestern Argentina. Their role in Andean magmatism and metallogenesis is well documented. In the southern Central Andes, Proterozoic rocks are so far known to outcrop in Argentina, east of the continental divide. In the course of U-Pb dating of the bimodal volcanic and sub-volcanic host rocks for Mesozoic manto-type copper deposits, we have encountered xenocrystic zircon with Proterozoic and Paleozoic ages. In the Punta del Cobre Cu-Fe (Au) District (27o30' S / 70o15' W) 22 km south of Copiapo xenocrystic zircon in the Lower Cretaceous host dacite yields ca. 1 Ga ages. In the El Soldado Cu District, (32o38' S /71o04' W), 120 km northwest of Santiago, scarce and strongly resorbed zircon crystals in the Lower Cretaceous host rhyodacite yield ages of 0.5 to 1.3 Ga. The early Cretaceous bimodal volcanic and subvolcanic rocks, which consists of primitive calc-alkaline basalts and rhyodacites, display geochemical evidence of crustal contamination. Our results suggest that, during their formation and ascent, the felsic magmas picked up zircons in the Proterozoic and Paleozoic crystalline basement of the Coastal Cordillera. The presence of Proterozoic (Grenville age) basement underlying localities as close as 30 km from the Pacific coast has implications for the extent and age of the Chilenia Terrane and gives further credence to correlation models that juxtapose eastern North America (Laurentia) and southwestern South America (Gondwana) during the Late Proterozoic (au)

  19. Parasites of the Green-backed Firecrown (Sephanoides sephaniodes) in Chile Parásitos del picaflor chico (Sephanoides sephaniodes) en Chile

    OpenAIRE

    Daniel González-Acuña; Carolina Silva; Marta Soto; Sergei Mironov; Lucila Moreno; González-Gómez, Paulina L.; Hasan Badrul; Mike Kinsella

    2011-01-01

    Gastrointestinal and external parasites from 12 Green-backed Firecrown (Sephanoides sephaniodes) were collected between January 2004 and December 2008 from the Biobío Region south-central Chile and Santiago (central Chile). Helminths collected included 1 trematode species (Mosesia sp.) and 1 cestode species (Hymenolepis trinidadensis). The mite Proctophyllodes huitzilopchtlii was the only ectoparasite species found. All these parasites represent new records for Chile and the first parasites r...

  20. Revisiting mountain-building in the Andes of Central Chile: constraints from structural geology and thermochronology.

    Science.gov (United States)

    Riesner, M.; Lacassin, R.; Simoes, M.; Armijo, R.; Carrizo, D.

    2015-12-01

    The Andes, one of the most significant reliefs on Earth, is the case example of a subduction-type mountain belt. In central Chile and western Argentina, the particular east-vergent structure of the Aconcagua fold-and-thrust belt (AFTB) is found atop a huge basement high with elevations > 4000 m, the Frontal Cordillera. Classical conceptual models consider the Andes as an east-vergent orogen, opposite to the Nazca subduction, and describe the exhumation of the Frontal Cordillera as an eastward in-sequence event that occurred late in the andean deformation (by ~10My). An alternative model recently challenged this view by proposing that the Andes have mainly a primary westward vergence. Within this scheme, the exhumation of the Frontal Cordillera would have begun earlier, by ~25My, synchronous with formation of the AFTB on the western side of the basement high. Here we test these two models by revisiting structural cross-sections of the Andes at the latitude of Santiago de Chile and of the Aconcagua (~33°S). We provide thermochronological constraints on the timing of exhumation of the Frontal Cordillera by (U-Th)/He dating on apatites retrieved from paleozoic granitoids along a 2,3km high nearly vertical section in the core of the basement high. Preliminary results suggest that the Frontal Cordillera exhumation was not a late event and likely began around 25 Ma. Therefore it appears to be synchronous with deformation within the AFTB and the westernmost fold-and-thrust belt at this latitude. We discuss these results and their implications while building a crustal-scale cross section of the range at the latitude of Santiago de Chile.

  1. Botanical Composition of Alpaca (Lama pacos Linn.) Diet in a Central Mediterranean Range of Chile Composición Botánica de la Dieta de Alpaca (Lama pacos Linn.) en un Pastizal del Secano Mediterráneo de la Zona Central de Chile

    OpenAIRE

    G Castellaro; F Squella N; F León C; A Raggi S

    2008-01-01

    The re-introduction of domestic South American camelids (alpacas and llamas) in the central zone of Chile makes it necessary to study their behaviour and adaptability. Since it is fundamental to characterize the camelid’s diet, the present work had as an objective the determination of the plant species selected by the alpacas (Lama pacos Linn.) in different phenological stages (vegetative, reproductive and dry season). The study was carried out over three years in a paddock of 2.5 ha of spars...

  2. Biogeochemistry of sulfur and iron in Thioploca-colonized surface sediments in the upwelling area off central Chile

    DEFF Research Database (Denmark)

    Zopfi, Jakob; Michael E., Böttcher; Jørgensen, Bo Barker

    2008-01-01

    The biogeochemistry of sedimentary sulfur was investigated on the continental shelf off central Chile at water depths between 24 and 88 m under partial influence of an oxygen minimum zone. Dissolved and solid iron and sulfur species, including the sulfur intermediates sulfite, thiosulfate, and el...

  3. The rock coast of South and Central America : chapter 10

    OpenAIRE

    Blanco-Chao, R.; Pedoja, K.; De Witt, C.; Martinod, J.; Husson, L.; Regard, V; Audin, Laurence; Nexer, M.; Delcaillau, B.; Saillard, M.; D. Melnick; Dumont, J.F.; Santana, E.; E Navarrete; Martillo, C.

    2014-01-01

    The great variety of climatic conditions, tidal ranges and wave regimes of South and Central America act on a complex geology and tectonic framework. Many of the rock and cliffed coasts of South America are strongly controlled by the occurrence of extensive Cenozoic and Pleistocene sediments that crop out at the coast. Geology and the different uplift rates are a major factor in the whole coastal geomorphology of South and Central America, and consequently are a very important control of the ...

  4. Environmental management in Chile: The power plants case; Gestion ambiental en Chile: Caso de las centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Jadrijevic, Maritza [Comision Nacional del Medio Ambiente, (Chile)

    1996-12-31

    In this paper are presented the general aspects of the historic evolution o the legal norms on environmental matters in Chile; general aspects of the electric generation system and the instruments of environmental management currently applied in the fossil fueled power plants, such as: the assessment system of the environmental impact; compliance of the air quality and emissions Standards and plans for decontamination [Espanol] En este trabajo se dan a conocer aspectos generales de la evolucion historica de las normas juridicas en materia ambiental en Chile; aspectos generales del sistema de generacion electrica y los instrumentos de gestion ambiental que actualmente se aplican a las plantas de generacion termoelectricas, tales como: el sistema de evaluacion de impacto ambiental; cumplimiento de normas de la calidad de aire y de emision y, planes de descontaminacion

  5. Revision of the Applicability of the NGA's in South America, Chile - Argentina.

    Science.gov (United States)

    Alvarado Lara, F., Sr.; Ledezma, C., Sr.

    2015-12-01

    In South America, larger magnitude seismic events originate in the subduction zone between the Nazca and Continental plates, as opposed to crustal events. Crustal seismic events are important in areas very close to active fault lines; however, seismic hazard analyses incorporate crust events related to a maximum distance from the site under study. In order to use crustal events as part of a seismic hazard analysis, it is necessary to use the attenuation relationships which represent the seismic behavior of the site under study. Unfortunately, in South America the amount of compiled crustal event historical data is not yet sufficient to generate a firm regional attenuation relationship. In the absence of attenuation relationships for crustal earthquakes in the region, the conventional approach is to use attenuation relationships from other regions which have a large amount of compiled data and which have similar seismic conditions to the site under study. This practice permits the development of seismic hazard analysis work with a certain margin of accuracy. In South America, in the engineering practice, new generation attenuation relationships (NGA-W) are used among other alternatives in order to incorporate the effect of crustal events in a seismic hazard analysis. In 2014, the NGA-W Version 2 (NGA-W2) was presented with a database containing information from Taiwan, Turkey, Iran, USA, Mexico, Japan, and Alaska. This paper examines whether it is acceptable to utilize the NGA-W2 in seismic hazard analysis in South America. A comparison between response spectrums of the seismic risk prepared in accordance with NGA-W2 and actual response spectrums of crustal events from Argentina is developed in order to support the examination. The seismic data were gathered from equipment installed in the cities of Santiago, Chile and Mendoza, Argentina.

  6. Sr-Nd isotope changes of late cretaceous to early miocene volcanic rocks in central Chile (33oS)

    International Nuclear Information System (INIS)

    A longitudinal depression, the Central Valley, separates the Coast Range from the Andean Cordillera in central Chile. It contains volcanic and volcaniclastic rocks of Late Cretaceous to Tertiary age deposited in a continental environment, and partly eroded Tertiary volcanic complexes. The age of the rocks at the northern end of the Central Valley and their grouping in formations have been a long-standing controversy in Chilean geology (Thomas, 1958; Aguirre, 1960; Drake et al., 1976; Vergara and Drake, 1979; Thiele, 1980; Moscoso et al., 1982; Gana and Wall, 1997; Lopez-Escobar and Vergara, 1997; Selles, 1999). Here, we report new 40Ar/39Ar data and Sr-Nd isotope ratios for lavas, pyroclastic flows and associated subvolcanic rocks from this part of central Chile (au)

  7. Nuclear Power in South-Central Brazil

    International Nuclear Information System (INIS)

    The region of South-Central Brazil includes the states of Sao Paulo, Rio de Janeiro, Guanabara and Minas Gerais. The most recent power study was made by Canambra Engineering Consultants Limited. This group reported that the public-grid electricity output for the area in 1962 was 2.16 GW (average generation), with an installed capacity of 3.41 GW and annual mean load factor of 63.4; an increase in power requirements for 1970 was forecast, corresponding to an average output of 5.37 GW and an installed capacity of 8.3 GW. This forecast was based on an annual growth rate of 11.9% in generation. ''The energy requirements have grown at an average annual rate of 10.9% since 1955; however, the present forecast is based on the assumption of power being available as required, and hence includes the suppressed demand resulting from existing restrictions in generating and distribution capacity''

  8. Riparian leaf litter processing by benthic macroinvertebrates in a woodland stream of central Chile Procesamiento de detritus ripariano por macroinvertebrados bentónicos en un estero boscoso de Chile central

    Directory of Open Access Journals (Sweden)

    CLAUDIO VALDOVINOS

    2001-06-01

    Full Text Available Leaf litter input from riparian landscapes has been identified as both a major energy flow to stream ecosystems and as a food source for stream macroinvertebrates. In riparian landscapes of woodland streams of central Chile, the native deciduous hardwoods are being artificially replaced by exotic coniferous trees at a large spatial scale. It is suggested that this process has a significant impact on the stream communities of central Chile. Today, exotic plantations occur throughout central Chile, with Pinus radiata (D. Don (Monterrey pine accounting for about 80 % of the more than 1,800,000 ha of exotic forests. The objective of this paper was to analyze the effect of the litter beds of a dominant native species (Nothofagus pumilio and an exotic species (P. radiata on the detritus processing carried out by benthic macroinvertebrates, in an experimental catchment of central Chile (Rucúe Creek; 36° 26'00" S, 71° 35'40" W. Results revealed that processing rates of native leaf packs are higher than rates of coniferous leaf packs, suggesting that the replacement of the native hardwoods by exotic coniferous riparian flora has an important impact on the stream energy flow in central Chile. The decay rate coefficients (k were 0.0072 for N. pumilio, and 0.0027 for P. radiata. The greater abundance and biomass of shredders per gram of leaf pack of native Nothofagus would explain the differences in leaf processing rates, especially through the activity of two Plecoptera Gripopterygidae, Limnoperla jaffueli and Antarctoperla michaelseniLa entrada de detritus foliar procedente de áreas riparianas ha sido reconocido como un componente importante en la energética de ecosistemas fluviales y como fuente de alimento de macroinvertebrados acuáticos. En áreas riparianas de esteros boscosos de Chile central los componentes nativos caducifolios están siendo artificialmente reemplazados a gran escala por coníferas exóticas, sugiriendo que este proceso tiene

  9. Notice Soliciting Subscription to “Journal of Central South University of Technology”

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Central South University is one of Chinese key universities,which is affiliated with the Ministry of Education."Journal of Central South University of Technology" (ISSN 1005?9784, CODEN JCSTFT) is sponsored by Central South University.

  10. Mycotrophy in Gilliesieae, a threatened and poorly known tribe of Alliaceae from central Chile Micotrofía en Gilliesieae, una tribu amenazada y poco conocida de Alliaceae de Chile central

    OpenAIRE

    GUSTAVO A TORRES-MELLADO; INELIA ESCOBAR; GOTZ PALFNER; M. ANGÉLICA CASANOVA-KATNY

    2012-01-01

    The five known genera of Gilliesieae have their diversity center in the Mediterranean zone of central Chile, where many of their habitats are threatened by urban expansion, industrial and agroforestry activities, as well as other anthropogenic impacts. Very little is known about the biology of these particular geophytes, the majority of which currently have either vulnerable or endangered status, mainly due to their dispersed and small populations generally associated to remnants of native ve...

  11. Lavas Las Pataguas: volcanismo alcalino en el antearco andino del Mioceno Inferior, Chile central Lavas Las Pataguas: alkaline volcanism in the Early Miocene Andean forearc of central Chile

    Directory of Open Access Journals (Sweden)

    Renate M Wall

    2001-12-01

    Full Text Available La presencia de rocas volcánicas del Mioceno Inferior en la cordillera de la Costa de Chile central constituye una singularidad ya que los afloramientos más occidentales del arco volcánico oligo-mioceno se encuentran 80 km al este. Lavas Las Pataguas (LLP; 33,8°S, se expone en 1,15 km², sin vestigios de un edificio volcánico ni conductos alimentadores. La presencia de túmulos del tipo `flow lobe tumuli', alineados y elongados en dirección este-oeste, indica un flujo local desde el oeste sobre una superficie de muy baja pendiente. Estos antecedentes sugieren un ciclo eruptivo de tipo fisural. La edad de LLP de ca. 18 Ma resulta intermedia entre las formaciones Abanico (34-20 Ma y Farellones (20-10 Ma y coetánea a facies litorales de la Formación Navidad, expuestas 20 km al oeste. LLP presenta contenidos de sílice de 52,8-54,5%, en el rango de las traquiandesitas basálticas, y su alto contenido de álcalis (6,21-6,26% de K2O+Na2O las sitúa en la serie alcalina de diferenciación. Destaca la clara diferencia con los productos toleíticos de la Formación Abanico, y los típicamente calcoalcalinos de la Formación Farellones. Estas lavas están significativamente enriquecidas en tierras raras livianas, con una razón La/Sm de 3,4 y un patrón plano de tierras raras pesadas. Tanto el contenido de sílice como de MgO, indican un estado de diferenciación avanzado dominado por cristalización fraccionada de olivino, clinopiroxeno y magnetita. El contenido de Ba y Nb señalaría una contribución significativa del manto litosférico. El Th, y la anomalía de Ta-Nb indicarían, también, un sello cortical. Su particular petrogénesis, así como su posición occidental y aislada en el antearco, podría explicarse como respuesta a la desaceleración de la convergencia con que culmina el ciclo extensional vigente hasta el Mioceno Inferior alto y que acompañó al volcanismo representado por la Formación Abanico. De este modo, las lavas

  12. A new species of Phymaturus (Iguania: Liolaemidae of the palluma group from Central Chile

    Directory of Open Access Journals (Sweden)

    Troncoso-Palacios, Jaime

    2012-07-01

    Full Text Available We examined specimens of Phymaturus from four locations in central Chile, between 34º50´S and 36º00´S (from Termas del Flaco and from Lircay and its surroundings, where the only recognized species is P. maulense. We found several differences in the scalation and in the color pattern among them. The samples from Lircay and its surroundings correspond to topotypes of P. maulense and two more populations assignable to this species (Termas del Campanario and Laguna del Maule, new records, but the specimens from Termas del Flaco are a new species: P. damasense. It is characterized by: dorsal pattern of the male formed by a thin reticulation over greenish background color with yellowish-brown tail, subocular scale fragmented in three or four scales, scales in the anterior border of the auditory meatus are projected posteriorly, females have dark bars on the flanks (formed by small spots, enlarged scales in the center of the gular fold and may have precloacar pores. Also, we call attention to some Chilean populations of the genus Phymaturus referred in the literature which need to be assigned. Examinamos especimenes de Phymaturus procedentes de cuatro localidades de Chile central, entre los 34º50'S y 36º00'S (Termas del Flaco y los alrededores de Lircay, donde la única especie reconocida es P. maulense. Estas poblaciones muestran diferencias en la escamación y en el diseño de coloración. Las muestras de la cuenca del Maule corresponden a topotipos de P. maulense y dos poblaciones más asignables a esta especie (Termas del Campanario y Laguna del Maule, nuevos registros, mientras que las poblaciones del río Las Damas constituyen una nueva especie caracterizada por: diseño dorsal del macho formado por una reticulación oscura sobre un fondo verde con cola café-amarillenta, escama subocular fragmentada en tres o cuatro, escamas agrandadas en el borde anterior del meato auditivo (proyectadas posteriormente, hembras con escamas agrandadas en el

  13. Metallurgical traditions under Inka rule: a technological study of metals and technical ceramics from the Aconcagua Valley, Central Chile

    OpenAIRE

    Plaza, M.T.; Martinón-Torres, M.

    2015-01-01

    The spread of the Inka state in the Aconcagua Valley (Central Chile) is thought to have been culturally mediated, avoiding military coercion, and thus leading to different forms of cultural acceptance, resistance or hybridisation. However, there has been no previous attempt to investigate the extent to which these interactions are reflected in the use of metals and metallurgical technologies. Here we present analytical work on metallic artefacts and technical ceramics from Cerro La Cruz and L...

  14. Methane in shallow cold seeps at Mocha Island off central Chile

    Science.gov (United States)

    Jessen, Gerdhard L.; Pantoja, Silvio; Gutiérrez, Marcelo A.; Quiñones, Renato A.; González, Rodrigo R.; Sellanes, Javier; Kellermann, Matthias Y.; Hinrichs, Kai-Uwe

    2011-04-01

    We studied for the first time the intertidal and subtidal gas seepage system in Mocha Island off Central Chile. Four main seepage sites were investigated (of which one site included about 150 bubbling points) that release from 150 to 240 tonnes CH 4 into the atmosphere per year. The total amount of methane emitted into the atmosphere is estimated in the order of 800 tonnes per year. The gases emanated from the seeps contain 70% methane, and the stable carbon isotopic composition of methane, δ 13C-CH 4 averaged -44.4±1.4‰ which indicates a major contribution of thermogenic gas. Adjacent to one of the subtidal seeps, rocky substrates support a diverse community of microbial filaments, macroalgae, and benthic organisms. While stable carbon isotopic compositions of marine benthic organisms indicate a dominant photosynthesis-based food web, those of some hard-substrate invertebrates were in the range -48.8‰ to -36.8‰, suggesting assimilation of methane-derived carbon by some selected taxa. This work highlights the potential subsidy of the trophic web by CH 4-C, and that its emission to the atmosphere justifies the need of evaluating the use of methane to support the energy requirements of the local community.

  15. Landsat image and sample design for water reservoirs (Rapel dam Central Chile).

    Science.gov (United States)

    Lavanderos, L; Pozo, M E; Pattillo, C; Miranda, H

    1990-01-01

    Spatial heterogeneity of the Rapel reservoir surface waters is analyzed through Landsat images. The image digital counts are used with the aim or developing an aprioristic quantitative sample design.Natural horizontal stratification of the Rapel Reservoir (Central Chile) is produced mainly by suspended solids. The spatial heterogeneity conditions of the reservoir for the Spring 86-Summer 87 period were determined by qualitative analysis and image processing of the MSS Landsat, bands 1 and 3. The space-time variations of the different observed strata obtained with multitemporal image analysis.A random stratified sample design (r.s.s.d) was developed, based on the digital counts statistical analysis. Strata population size as well as the average, variance and sampling size of the digital counts were obtained by the r.s.s.d method.Stratification determined by analysis of satellite images were later correlated with ground data. Though the stratification of the reservoir is constant over time, the shape and size of the strata varys. PMID:24243254

  16. Effects of maize cultivation on nitrogen and phosphorus loadings to drainage channels in Central Chile.

    Science.gov (United States)

    Corradini, Fabio; Nájera, Francisco; Casanova, Manuel; Tapia, Yasna; Singh, Ranvir; do Salazar, Osval

    2015-11-01

    There are concerns about the impact of maize cultivation with high applications of nitrogen (N) and phosphorus (P) on water quality in surface waters in Mediterranean Central Chile. This study estimated the contribution of N and P from maize fields to nearby drainage channels and evaluated the effects in water quality. An N and P budget was drawn up for three fields managed with a maize-fallow system, El Maitén (20.7 ha), El Naranjal (14.9 ha) and El Caleuche (4.2 ha), and water quality variables (pH, EC, dissolved oxygen, total solids, turbidity, NO3-N, NH4-N, PO4(3-), COD, total N, total P and sulphate) were monitored in nearby drainage channels. The N and P balances for the three fields indicated a high risk of N and P non-point source pollution, with fertiliser management, soil texture and climate factors determining the temporal variations in water quality parameters. Elevated levels of NH4-N and PO4(3-) in the drainage channels were usually observed during the winter period, while NO3- concentrations did not show a clear tendency. The results suggest that excessive slurry application during winter represents a very high risk of N and P runoff to drainage channels. Overall, great emphasis must be placed on good agronomic management of fields neighbouring drainage channels, including accurately calculating N and P fertiliser rates and establishing mitigation measures. PMID:26490735

  17. Marine protected areas facilitate parasite populations among four fished host species of central Chile.

    Science.gov (United States)

    Wood, Chelsea L; Micheli, Fiorenza; Fernández, Miriam; Gelcich, Stefan; Castilla, Juan Carlos; Carvajal, Juan

    2013-11-01

    1. Parasites comprise a substantial proportion of global biodiversity and exert important ecological influences on hosts, communities and ecosystems, but our knowledge of how parasite populations respond to human impacts is in its infancy. 2. Here, we present the results of a natural experiment in which we used a system of highly successful marine protected areas and matched open-access areas in central Chile to assess the influence of fishing-driven biodiversity loss on parasites of exploited fish and invertebrate hosts. We measured the burden of gill parasites for two reef fishes (Cheilodactylus variegatus and Aplodactylus punctatus), trematode parasites for a keyhole limpet (Fissurella latimarginata), and pinnotherid pea crab parasites for a sea urchin (Loxechinus albus). We also measured host density for all four hosts. 3. We found that nearly all parasite species exhibited substantially greater density (# parasites m(-2)) in protected than in open-access areas, but only one parasite species (a gill monogenean of C. variegatus) was more abundant within hosts collected from protected relative to open-access areas. 4. These data indicate that fishing can drive declines in parasite abundance at the parasite population level by reducing the availability of habitat and resources for parasites, but less commonly affects the abundance of parasites at the infrapopulation level (within individual hosts). 5. Considering the substantial ecological role that many parasites play in marine communities, fishing and other human impacts could exert cryptic but important effects on marine community structure and ecosystem functioning via reductions in parasite abundance. PMID:23855822

  18. Soundscape of a management and exploitation area of benthic resources in central Chile

    Directory of Open Access Journals (Sweden)

    Alfredo Borie

    2015-11-01

    Full Text Available Acoustic ecology is an emerging and poorly known field of research. Soundscape has been used to infer the behavior of several species in different environments and can serve as a reliable indicator of the habitat type and quality; also, it is believed that it is an important factor for larvae orientation in settlement areas. We used the passive acoustic method to evaluate the soundscape of a management and exploitation area of benthic resources, a rocky reef area in central Chile. It was possible to hear a continuous cracking sound during recording and underwater observations. We detected two distinct frequency bands with similar parameters during the night and day, a band between 90 and 300 Hz, which corresponded to the effects of sea waves (geophony, and a frequency band with a range of 1,500 to 2,700 Hz (biophony, with a fundamental frequency of 2,070 Hz. Both bands had similar energy (~88.0 dB re: 1V/µPa. These results show the relevant acoustic activity in the area, which may have important ecological implications for the recruitment of commercially important benthic resources.

  19. Analyzing Food-Related Life Satisfaction and other Predictors of Life Satisfaction in Central Chile.

    Science.gov (United States)

    Schnettler, Berta; Lobos, Germán; Orellana, Ligia; Grunert, Klaus; Sepúlveda, José; Mora, Marcos; Denegri, Marianela; Miranda, Horacio

    2015-01-01

    This study aimed to assess the effect of satisfaction with food-related life on life satisfaction among inhabitants of the main municipalities of central Chile. A survey was applied to a sample of 1,277 people, distributed proportionally by municipality. The questionnaire included the following scales: SWLS (Satisfaction with Life Scale), SWFL (Satisfaction with Food-related Life) and the Health-Related Quality of Life Index (HRQOL). Questions were asked regarding eating habits inside and outside the home, time available for meals at home, the assessment of five sources of happiness and the demographic characteristics of those surveyed. An ordered logit model was proposed, in which the dependent variable was satisfaction with life. Satisfaction with life was significantly related to the respondent's socioeconomic status, self-perception of health, degree of satisfaction with food-related life, monthly food expenditure, time available for supper with the family (p consumption in fast food outlets (p < .10). Satisfaction with life in the study sample is related to aspects associated with health, family and eating, and the family interaction associated with eating may play an important role in overall satisfaction with life. PMID:26083311

  20. 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

  1. A Centralized Auction Mechanism for the Disability and Survivors Insurance in Chile

    Science.gov (United States)

    Reyes H., Gonzalo

    As part of the pension reform recently approved in Chile, the government introduced a centralized auction mechanism to provide the Disability and Survivors (D&S) Insurance that covers recent contributors among the more than 8 million participants in the mandatory private pension system. This paper is intended as a case study presenting the main distortions found in the decentralized operation of the system that led to this reform and the challenges faced when designing a competitive auction mechanism to be implemented jointly by the Pension Fund Managers (AFP). In a typical bilateral contract the AFP retained much of the risk and the Insurance Company acted in practice as a reinsurer. The process to hire this contract was not competitive and colligated companies ended up providing the service. Several distortions affected competition in the market through incentives to cream-skim members by AFPs (since they bear most of the risk) or efforts to block disability claims. Since the price of this insurance is hidden in the fees charged by AFPs for the administration of individual accounts and pension funds there was lack of price transparency. Since new AFPs have no history of members’ disability and mortality profile the insurance contract acted as a barrier to entry in the market of AFP services, especially when D&S insurance costs reached 50% of total costs. Cross-subsidies between members of the same AFP, inefficient risk pooling (due to pooling occurring at the AFP rather than at the system level) and regulatory arbitrage, since AFPs provided insurance not being regulated as an insurance company, were also present. A centralized auction mechanism solves these market failures, but also gives raise to new challenges, such as how to design a competitive auction that attracts participation and deters collusion. Design features that were incorporated in the regulation to tackle these issues, such as dividing coverage into predefined percentage blocks, are presented

  2. Antibacterial Activity, Antioxidant Effect and Chemical Composition of Propolis from the Región del Maule, Central Chile

    Directory of Open Access Journals (Sweden)

    Nélida Nina

    2015-10-01

    Full Text Available Propolis is commercialized in Chile as an antimicrobial agent. It is obtained mainly from central and southern Chile, but is used for the same purposes regardless of its origin. To compare the antimicrobial effect, the total phenolic (TP, the total flavonoid (TF content and the phenolic composition, 19 samples were collected in the main production centers in the Región del Maule, Chile. Samples were extracted with MeOH and assessed for antimicrobial activity against Gram (+ and Gram (− bacteria. TP and TF content, antioxidant activity by the DPPH, FRAP and TEAC methods were also determined. Sample composition was assessed by HPLD-DAD-ESI-MS/MS. Differential compounds in the samples were isolated and characterized. The antimicrobial effect of the samples showed MICs ranging from 31.5 to > 1000 µg/mL. Propolis from the central valley was more effective as antibacterial than those from the coastal area or Andean slopes. The samples considered of interest (MIC ≤ 62.5 µg/mL showed effect on Escherichia coli, Pseudomonas sp., Yersinia enterocolitica and Salmonella enteritidis. Two new diarylheptanoids, a diterpene, the flavonoids pinocembrin and chrysin were isolated and elucidated by spectroscopic and spectrometric means. Some 29 compounds were dereplicated by HPLC-MS and tentatively identified, including nine flavones/flavonol derivatives, one flavanone, eight dihydroflavonols and nine phenyl-propanoids. Propolis from the Región del Maule showed large variation in antimicrobial effect, antioxidant activity and composition. So far the presence of diarylheptanoids in samples from the coastal area of central Chile can be considered as a marker of a new type of propolis.

  3. Oil and gas developments in South America, Central America, Caribbean area, and Mexico in 1987

    Energy Technology Data Exchange (ETDEWEB)

    Wiman, W.D.

    1988-10-01

    Exploration activity in South America, Central America, the Caribbean area, and Mexico in 1987 showed significant increases in seismic acquisition in Belize, Bolivia, Brazil, Costa Rica, Guatemala, Mexico, Paraguay, and Peru, and a decrease in Chile and Venezuela. Exploratory drilling increased in most major producing countries but was accompanied by a decline in development drilling. Most of the increase could be attributed to private companies fulfilling obligations under risk contracts; however, state oil companies in Bolivia, Chile, and Colombia showed significant increased activity, with only Mexico showing a decrease. Colombia again had a dramatic increase in production (29% from 1986). Noteworthy discoveries were made in Bolivia (Villamontes-1); Brazil, in the Solimoes basin (1-RUC-1-AM); Chile (Rio Honda-1); Colombia, in the Llanos basin (Austral-1, La Reforma-1, Libertad Norte-1, Cravo Este-1, and Cano Yarumal-1), in the Upper Magdalena basin (Toldado-1 and Los Mangos-1); Ecuador (Frontera-1, a joint-exploration venture with Colombia); Mexico, in the Chiapas-Tabasco region (Guacho-1 and Iridi-1), in the Frontera Norte area (Huatempo-1); Peru, in the Madre de Dios basin (Armihuari-4X); Trinidad (West East Queen's Beach-1); and Venezuela (Musipan-1X). Brazil's upper Amazon (Solimoes basin) discovery, Colombia's Upper Magdalena basin discoveries Toldado-1 and Los Mangos-1, Mexico's Chiapas-Tabasco discoveries, Peru's confirmation of the giant Cashiriari discovery of 1986, and Venezuela's success in Monagas state were the highlights of 1987. 5 figs., 8 tabs.

  4. Aspectos de manejo y bienestar en equinos de tiro urbano en el sur de Chile Husbandry and welfare aspects of urban draught horses in the south of Chile

    Directory of Open Access Journals (Sweden)

    T Tadich

    2008-01-01

    Full Text Available En el sur de Chile los equinos de tiro continúan siendo la fuente principal de ingreso para numerosas familias. En muchas ocasiones estos equinos de trabajo no son mantenidos en óptimas condiciones. El objetivo de este estudio fue determinar las prácticas de manejo y parámetros relacionados con bienestar animal en un grupo de sesenta y un equinos carretoneros, pertenecientes a cincuenta propietarios, de tres ciudades del sur de Chile (Valdivia, Osorno y Puerto Montt. Se utilizaron métodos directos (basados en el animal y métodos indirectos. Estos incluyeron aspectos de salud, comportamiento y prácticas de manejo. La mayoría de los equinos presentaron una conformación masisa, pero más pequeña que la de las razas de tiro clásicas encontradas en otras áreas templadas en el mundo. En general presentaron buena condición corporal (59% y alertas (92%, con sólo unos pocos animales que presentaron una respuesta agresiva al momento de evaluar su comportamiento. Los principales problemas encontrados están relacionados con el manejo de cascos y las prácticas de alimentación. No se encontró asociación entre buena conformación de cascos y el uso de herreros o experiencia de los dueños. Esto se debe principalmente a una carencia de conocimiento y comprensión de prácticas de manejo y trabajo adecuados que permitan obtener un mejor rendimiento de sus equinos sin poner en riesgo el bienestar de éstos. La comunidad de dueños de equinos de trabajo se vería beneficiada con la instauración de programas educacionales en el futuro.In the south of Chile draught horses are the main source of household income for many families and often these working horses are kept in conditions that are far from ideal. The aim of this study was to determine husbandry practices and welfare parameters for a group of sixty one urban draught horses belonging to fifty owners, from three cities (Valdivia, Osorno and Puerto Montt in the south of Chile. Direct

  5. Assessment of undiscovered petroleum resources in Central and South America

    Science.gov (United States)

    Schenk, C.J.

    2002-01-01

    The USGS has assessed undiscovered conventional oil and gas resources in 128 selected petroleum provinces of the world. Of these 128 provinces, 23 are in South America, Central America, and the Caribbean area. In the USGS 2000 Assessment, the provinces resulted in mean totals for undiscovered resource of 105 billion bbl of oil and 487 tcf of gas. The potential for giant oil and gas fields is greatest in the basins along the Atlantic margin of eastern South America, from the Santos Basin in the south to the Guyana-Suriname Basin in the north. The potential for giant fields is mainly offshore, in water depths up to 3600 m. The South and Central America region ranks third in the world for undiscovered conventional oil and gas behind the Middle East and the Former Soviet Union.

  6. Paleowetlands and regional climate change in the central Atacama Desert, northern Chile

    Science.gov (United States)

    Quade, Jay; Rech, Jason A.; Betancourt, Julio L.; Latorre, Claudio; Quade, Barbra; Rylander, Kate Aasen; Fisher, Timothy

    2008-05-01

    Widespread, organic-rich diatomaceous deposits are evidence for formerly wetter times along the margins of the central Atacama Desert, one of the driest places on Earth today. We mapped and dated these paleowetland deposits at three presently waterless locations near Salar de Punta Negra (24.5°S) on the western slope of the Andes. Elevated groundwater levels supported phreatic discharge into wetlands during two periods: 15,900 to ~ 13,800 and 12,700 to ~ 9700 cal yr BP. Dense concentrations of lithic artifacts testify to the presence of paleoindians around the wetlands late in the second wet phase (11,000?-9700 cal yr BP). Water tables dropped below the surface before 15,900 and since 8100 cal yr BP, and briefly between ~ 13,800 and 12,700 cal yr BP. This temporal pattern is repeated, with some slight differences, in rodent middens from the study area, in both paleowetland and rodent midden deposits north and south of the study area, and in lake level fluctuations on the adjacent Bolivian Altiplano. The regional synchroneity of these changes points to a strengthening of the South American Monsoon — which we term the "Central Andean Pluvial Event" — in two distinct intervals (15,900-13,800 and 12,700-9700 cal yr BP), probably induced by steepened SST gradients across the tropical Pacific (i.e., La Niña-like conditions).

  7. Paleowetlands and regional climate change in the central Atacama Desert, northern Chile

    Science.gov (United States)

    Quade, Jay; Rech, Jason A.; Betancourt, Julio L.; Latorre, Claudio; Quade, Barbra; Rylander, Kate Aasen; Fisher, Timothy

    2008-01-01

    Widespread, organic-rich diatomaceous deposits are evidence for formerly wetter times along the margins of the central Atacama Desert, one of the driest places on Earth today. We mapped and dated these paleowetland deposits at three presently waterless locations near Salar de Punta Negra (24.5°S) on the western slope of the Andes. Elevated groundwater levels supported phreatic discharge into wetlands during two periods: 15,900 to ~ 13,800 and 12,700 to ~ 9700 cal yr BP. Dense concentrations of lithic artifacts testify to the presence of paleoindians around the wetlands late in the second wet phase (11,000?–9700 cal yr BP). Water tables dropped below the surface before 15,900 and since 8100 cal yr BP, and briefly between ~ 13,800 and 12,700 cal yr BP. This temporal pattern is repeated, with some slight differences, in rodent middens from the study area, in both paleowetland and rodent midden deposits north and south of the study area, and in lake level fluctuations on the adjacent Bolivian Altiplano. The regional synchroneity of these changes points to a strengthening of the South American Monsoon — which we term the "Central Andean Pluvial Event" — in two distinct intervals (15,900–13,800 and 12,700–9700 cal yr BP), probably induced by steepened SST gradients across the tropical Pacific (i.e., La Niña-like conditions).

  8. Post-earthquake coastal evolution and recovery of an embayed beach in central-southern Chile

    Science.gov (United States)

    Martínez, Carolina; Rojas, Daniel; Quezada, Matías; Quezada, Jorge; Oliva, Ricardo

    2015-12-01

    Earthquakes and tsunamis are significant factors for change along active margin shores, and influence coastal evolution. The Chilean coast was affected in 2010 by a subduction earthquake with a magnitude of Mw 8.8 and also by a trans-Pacific tsunami, which generated violent geomorphologic changes and damaged homes. Following these events, the magnitude of the changes which affect Chile's central-southern coast (37°S) and the role of subduction earthquakes in coastal evolution on a historical scale were investigated. At Lebu bay (an embayed beach) data were generated for variations in time and space along the shoreline, topographical and bathymetric changes in the bay, and for morphodynamic littoral processes. Logarithmic and parabolic models were applied to the shoreline along with map overlays in order to determine changes. The shoreline processes were analyzed based on statistics for waves, tides and sediment transport for pre- and post-tsunami conditions. An average accretion rate of 2.80 m/year (1984-2010) was established for the shoreline, with a strong trend towards accretion in the last 30 years. A parabolic function best represented the general form of the shoreline, although the presence of a river in the concave zone affected the fit in this sector. Two factors controlled historical changes on the beach: one of anthropic origin in addition to the earthquake and tsunami on February 27th, 2010. The post-earthquake recovery was fast, and currently the beach is in a stable condition despite the inter-seismic subsidence process previous to the event. This coastal system showed a high resilience in the face of coastal geomorphological changes induced by high-impact natural disturbances. However, the opposite occurred in relation to changes induced by anthropogenic disturbances.

  9. Assessing the benefits and costs of dryland forest restoration in central Chile.

    Science.gov (United States)

    Schiappacasse, Ignacio; Nahuelhual, Laura; Vásquez, Felipe; Echeverría, Cristian

    2012-04-30

    Investment in natural capital restoration is increasing as a response to the widespread ecological degradation of dryland forests. However, finding efficient mechanisms to promote restoration among private landowners is a significant challenge for policy makers with limited financial resources. Furthermore, few attempts have been made to evaluate the costs and benefits of restoration interventions even though this information is relevant to orient decision making. Hence, our goal was to estimate the benefits and costs of dryland forest restoration by means of reforestation with native trees in a study area in central Chile. To determine benefits we applied a Contingent Valuation questionnaire that allowed for the calculation of willingness to pay measures. Restoration costs were calculated based on market prices following existing technical recommendations developed for the study area. The results showed that the restoration project had a negative NPV irrespective of the discount rate applied in the analysis. Thus, the NPV varied between -US$71,000 and -US$258,000. The NPV attained positive results only for negative discount rates (US$15,039 for -2%) and only when the national subsidy available for forest restoration was taken into account. This shows that landowners in Colliguay do not have incentives for carrying out restoration interventions due to a classic market failure: that in which ecosystems are mismanaged because many of their benefits are externalities from the perspective of landowners. Overall, these results stress the need for developing new compensation mechanisms and enhancing those in existence, with the aim of making restoration competitive with other land uses. PMID:22325581

  10. Climate change adaptation in a highly urbanized snowmelt dominated basin in Central Chile

    Science.gov (United States)

    Vicuna, S.; Bustos, E.; Merino, P.; Henriquez Dole, L. E.; Jansen, S.; Gil, M.; Ocampo, A.; Poblete, D.; Tosoni, D.; Meza, F. J.; Donoso, G.; Melo, O.

    2015-12-01

    The Maipo river basin holds 40% of Chile's total population and produces almost half of the country's Gross Domestic Product. The basin is located in the semiarid and snowmelt dominated central region of the country and, aside from the typical pressures of growth in developing country basins, the Maipo river basin faces climate change impacts associated with a reduction in total runoff and changes in its seasonality. Surface water is the main water source for human settlements, natural ecosystems, and economic activities including agriculture, mining and hydropower production. In 2012 a research project, called MAPA (Maipo Plan de Adaptacion), began with the objective of articulating a climate variability and climate change adaptation plan for the Maipo river basin. The project engaged at the beginning a group of relevant water and land use stakeholders which allowed for a good representation of critical aspects of an adaptation plan such as the definition of objectives and performance indicators, future land use scenarios, modeling of the different components of the system and design of adaptation strategies. The presentation will highlight the main results of the research project with a special focus on the upper catchments of the basin. These results include the assessment of impacts associated with future climate and land use scenarios on key components of the hydrologic cycle including snowmelt and glacier contribution to runoff and subsequent impacts on water availability for the operation of hydropower facilities, satisfaction of instream (recreation and aquatic ecosystem) uses and provision of water for the city of Santiago (7 million people) and to irrigate more than 100,000 hectares of high value crops. The integrative approach followed in this project including different perspectives on the use of water in the basin provides a good opportunity to test the varying degree of impacts that could be associated with a given future scenario and also understand

  11. International stock market integration: Central and South Eastern Europe compared

    Czech Academy of Sciences Publication Activity Database

    Horváth, Roman; Petrovski, D.

    2013-01-01

    Roč. 37, č. 1 (2013), s. 81-91. ISSN 0939-3625 R&D Projects: GA ČR GA402/09/0965 Institutional support: RVO:67985556 Keywords : stock markets * South Eastern Europe Subject RIV: AH - Economics Impact factor: 0.611, year: 2013 http://library.utia.cas.cz/separaty/2013/E/horvath-international stock market integration central and south eastern europe compared.pdf

  12. Investigation of Genetic Variation Underlying Central Obesity amongst South Asians

    Science.gov (United States)

    Scott, William R.; Zhang, Weihua; Loh, Marie; Tan, Sian-Tsung; Lehne, Benjamin; Afzal, Uzma; Peralta, Juan; Saxena, Richa; Ralhan, Sarju; Wander, Gurpreet S.; Bozaoglu, Kiymet; Sanghera, Dharambir K.; Elliott, Paul; Scott, James; Chambers, John C.; Kooner, Jaspal S.

    2016-01-01

    South Asians are 1/4 of the world’s population and have increased susceptibility to central obesity and related cardiometabolic disease. Knowledge of genetic variants affecting risk of central obesity is largely based on genome-wide association studies of common SNPs in Europeans. To evaluate the contribution of DNA sequence variation to the higher levels of central obesity (defined as waist hip ratio adjusted for body mass index, WHR) among South Asians compared to Europeans we carried out: i) a genome-wide association analysis of >6M genetic variants in 10,318 South Asians with focused analysis of population-specific SNPs; ii) an exome-wide association analysis of ~250K SNPs in protein-coding regions in 2,637 South Asians; iii) a comparison of risk allele frequencies and effect sizes of 48 known WHR SNPs in 12,240 South Asians compared to Europeans. In genome-wide analyses, we found no novel associations between common genetic variants and WHR in South Asians at P<5x10-8; variants showing equivocal association with WHR (P<1x10-5) did not replicate at P<0.05 in an independent cohort of South Asians (N = 1,922) or in published, predominantly European meta-analysis data. In the targeted analyses of 122,391 population-specific SNPs we also found no associations with WHR in South Asians at P<0.05 after multiple testing correction. Exome-wide analyses showed no new associations between genetic variants and WHR in South Asians, either individually at P<1.5x10-6 or grouped by gene locus at P<2.5x10−6. At known WHR loci, risk allele frequencies were not higher in South Asians compared to Europeans (P = 0.77), while effect sizes were unexpectedly smaller in South Asians than Europeans (P<5.0x10-8). Our findings argue against an important contribution for population-specific or cosmopolitan genetic variants underlying the increased risk of central obesity in South Asians compared to Europeans. PMID:27195708

  13. Investigation of Genetic Variation Underlying Central Obesity amongst South Asians.

    Directory of Open Access Journals (Sweden)

    William R Scott

    Full Text Available South Asians are 1/4 of the world's population and have increased susceptibility to central obesity and related cardiometabolic disease. Knowledge of genetic variants affecting risk of central obesity is largely based on genome-wide association studies of common SNPs in Europeans. To evaluate the contribution of DNA sequence variation to the higher levels of central obesity (defined as waist hip ratio adjusted for body mass index, WHR among South Asians compared to Europeans we carried out: i a genome-wide association analysis of >6M genetic variants in 10,318 South Asians with focused analysis of population-specific SNPs; ii an exome-wide association analysis of ~250K SNPs in protein-coding regions in 2,637 South Asians; iii a comparison of risk allele frequencies and effect sizes of 48 known WHR SNPs in 12,240 South Asians compared to Europeans. In genome-wide analyses, we found no novel associations between common genetic variants and WHR in South Asians at P<5x10-8; variants showing equivocal association with WHR (P<1x10-5 did not replicate at P<0.05 in an independent cohort of South Asians (N = 1,922 or in published, predominantly European meta-analysis data. In the targeted analyses of 122,391 population-specific SNPs we also found no associations with WHR in South Asians at P<0.05 after multiple testing correction. Exome-wide analyses showed no new associations between genetic variants and WHR in South Asians, either individually at P<1.5x10-6 or grouped by gene locus at P<2.5x10-6. At known WHR loci, risk allele frequencies were not higher in South Asians compared to Europeans (P = 0.77, while effect sizes were unexpectedly smaller in South Asians than Europeans (P<5.0x10-8. Our findings argue against an important contribution for population-specific or cosmopolitan genetic variants underlying the increased risk of central obesity in South Asians compared to Europeans.

  14. Dieta del pez espada Xiphias gladius Linnaeus, 1758, en aguas oceánicas de Chile central en invierno de 2003 Diet of the swordfish Xiphias gladius Linnaeus, 1758 in oceanic waters off central Chile in winter 2003

    OpenAIRE

    Christian M Ibáñez; Carlos González; Luis Cubillos

    2004-01-01

    Se analiza la dieta del pez espada en tres zonas de pesca en aguas oceánicas de Chile central durante el invierno de 2003, considerando como hipótesis que el tamaño de las presas se incrementa significativamente con el tamaño del depredador, conjuntamente con una disminución del número de presas. El estudio se realizó sobre la base de 48 estómagos de Xiphias gladius con contenido estomacal. Para su análisis se utilizó los descriptores cuantitativos de frecuencia de ocurrencia y método numéric...

  15. Persistent toxic substances in soils and waters along an altitudinal gradient in the Laja River Basin, Central Southern Chile.

    Science.gov (United States)

    Barra, Ricardo; Popp, Peter; Quiroz, Roberto; Bauer, Coretta; Cid, Hernan; von Tümpling, Wolf

    2005-02-01

    In this study the levels and distribution of some persistent toxic substances (PTS) were investigated in soils, superficial water, and snow along an altitudinal gradient in the Laja River Basin (South Central Chile). The principal objective was to establish the basin's contamination status. The working hypothesis was that PTS levels and distribution in the basin are dependent on the degree of anthropogenic intervention. Fifteen PAHs, seven PCBs congeners, and three organochlorine pesticides were studied in superficial soil and water samples obtained along the altitudinal gradient and from a coastal reference station (Lleu-Lleu River). Soil samples were extracted using accelerated solvent extraction with acetone/cyclohexane (1:1) for PAHs and organochlorine compounds. Contaminants were extracted from water and snow samples by liquid-liquid extraction (LLE). PAH and organochlorine compound quantification was carried out by HPLC with fluorescence detection and GC-MS, respectively. PCBs in soils presented four different profiles in the altitudinal gradient, mainly determined by their chlorination degree; these profiles were not observed for the chlorinated pesticides. In general, the detected levels for the analyzed compounds were low for soils when compared with soil data from other remote areas of the world. Higher summation operator PAHs levels in soils were found in the station located at 227 masl (4243 ng g-1 TOC), in a forestry area and near a timber industry, where detected levels were up to eight times higher than the other sampling sites. In general, PAH levels and distribution seems to be dependent on local conditions. No pesticides were detected in surface waters. However, congeners of PCBs were detected in almost all sampling stations with the highest levels being found in Laja Lake waters, where 1.1 ng/l were observed. This concentration is two times higher than values reported for polluted lakes in the Northern Hemisphere. The presence of organochlorine

  16. El aprecio por el paisaje y su utilidad en la conservación de los paisajes de Chile Central

    OpenAIRE

    Gonzalo de la Fuente de Val; José A. Atauri Mezquida; José V. de Lucio Fernández

    2004-01-01

    La transformación del paisaje mediterráneo de Chile Central comienza a plantearse en la sociedad como una prioridad en todas sus dimensiones y funcione. Se consideran no sólo sus factores ecológicos, sociales, económicos sino también culturales, escénicos y afectivos. Se ha sugerido la percepción del paisaje como una pieza significativa para emprender nuevas formas de relación con el entorno. Este trabajo ilustra los resultados generales de un amplio estudio de preferencias paisajísticas y me...

  17. Palaeoenvironment reconstruction, volcanic evolution and geochronology of the Cerro Blanco subcomplex, Nevados de Chillan volcanic complex, Central Chile

    OpenAIRE

    Mee, Katy; Gilbert, Jennie S.; McGarvie, David W.; Naranjo, Jose A.; Pringle, Malcolm S.

    2009-01-01

    Nevados de Chillán Volcanic Complex, central Chile, has been active for at least 640 ka—a period spanning a number of glacial and interglacial periods. Geologic mapping, radiometric dating and geochemical analysis have identified six new volcanic units and produced four new 40Ar/39Ar ages for Cerro Blanco, the northern subcomplex of Nevados de Chillán volcano. Compositions range from dacite to basaltic-andesite and a new geologic map is presented. Examination of lava fracture structures on bo...

  18. Syntectonic emplacement of the Middle Jurassic Concon Mafic Dike Swarm, Coastal Range, central Chile (33 degrees S)

    OpenAIRE

    C. Creixell; M.A. Parada; Roperch, Pierrick; D. Morata; Arriagada, C; Arce, C.P. de

    2006-01-01

    The Concon Mafic Dike Swarm (CMDS) consists of basaltic to andesitic dikes emplaced into deformed Late Palcozoic granitoids during the development of the Jurassic arc of central Chile. The dikes are divided into an early group of thick dikes (512 in) and a late group of thin dikes (0.5-3 m). Two new amphibole Ar-40/Ar-39 dates obtained from undeformed and deformed dikes, constrain the age of emplacement and deformation of the CMDS between 163 and 157 Ma. Based on radiometric ages, field obser...

  19. A new species of Phymaturus (Iguania: Liolaemidae) of the palluma group from Central Chile

    OpenAIRE

    Troncoso-Palacios, Jaime; Lobo, Fernando

    2012-01-01

    We examined specimens of Phymaturus from four locations in central Chile, between 34º50´S and 36º00´S (from Termas del Flaco and from Lircay and its surroundings), where the only recognized species is P. maulense. We found several differences in the scalation and in the color pattern among them. The samples from Lircay and its surroundings correspond to topotypes of P. maulense and two more populations assignable to this species (Termas del Campanario and Laguna del Maule, new records), but t...

  20. Radiometric dating of the postorogenic Graversfors granite, south central Sweden

    International Nuclear Information System (INIS)

    A Rb-Sr whole rock isochron dating has yielded an age of 1692 +- 7 Ma on the Graversfors granite, south central Sweden. The 280 Ma higher U-Pb discordia age of 1971 +51 -43 Ma suggests a previous history for the zircons. The Rb-Sr mineral systems finally closed 1641 +- 17 Ma ago. (Author)

  1. Water Erosion Prediction Using the Revised Universal Soil Loss Equation (RUSLE) in a GIS Framework, Central Chile Estimación de la Erosión Hídrica Empleando la Ecuación Universal de Pérdida de Suelo Revisada (RUSLE) y SIG en Chile Central

    OpenAIRE

    Carlos A. Bonilla; Reyes, José L.; Antoni Magri

    2010-01-01

    Soil erosion is a growing problem in Central Chile, particularly in coastal dry lands, where it can significantly decrease the productivity of rainfed agriculture and forestry. In this study, the Revised Universal Soil Loss Equation (RUSLE) was integrated into a Geographic Information System (GIS), and used to evaluate the effects of different combinations of vegetative cover on soil erosion rates for Santo Domingo County in Central Chile. Implementing RUSLE in the GIS required a complete des...

  2. Estimation of real evapotranspiration and its variation in Mediterranean landscapes of central-southern Chile

    Science.gov (United States)

    Olivera-Guerra, L.; Mattar, C.; Galleguillos, M.

    2014-05-01

    Evapotranspiration (ETd) is a key controller in the ecohydrological processes of semi-arid landscapes. This is the case of the dry land in Chile's central-southern zone, where forestry, farming and livestock activities must adapt to precipitation with considerable year-on-year variations. In this study, the spatial distribution of ETd was estimated in relation to the land use map and physical parameters of the soil. The ETd was estimated through the Simplified Surface Energy Balance Index (S-SEBI) using data from weather stations and remote data provided by the ASTER and MODIS sensors for November 2004 and 2006, respectively. The spatial variability of ETd was compared among different plant types, soil textural classes and depths using non-parametric statistical tests. In this comparison, the highest rates of ETd were obtained in the forest covers with values of 7.3 ± 0.8 and 8.4 ± 0.8 mm d-1 for 2004 and 2006, respectively. The lowest values were estimated for pastures and shrublands with values of 3.5 ± 1.2 mm d-1 and for crops with rates of 4.4 ± 1.6 mm d-1. Comparison of the ETd of the native forest covers and plantations of exotic species showed statistically significant differences; however, no great variation was noted, at least in the study months. Additionally, the highest rates of ETd were found in the clay loam textures (6.0 ± 1.8 and 6.4 ± 2.0 mm d-1) and the lowest rates in the sandy loam soils (3.7 ± 1.6 and 3.9 ± 1.6 mm d-1) for 2004 and 2006, respectively. The results enable analysis of the spatial patterns of the landscape in terms of the relation between water consumption, ET and the biophysical characteristics of a Mediterranean ecosystem. These results form part of the creation of tools useful in the optimization of decision-making for the management and planning of water resources and soil use in territories with few measuring instruments.

  3. Coastal, valley, and oasis interaction: impact on the evolution of ancient populations in the South Central Andes.

    Science.gov (United States)

    Varela, Héctor H; Cocilovo, Jose A; Fuchs, María L; O'Brien, Tyler G

    2014-12-01

    The existing biocultural links are analyzed among ancient inhabitants of the Cochabamba valleys (Bolivia) from the Formative and Tiwanaku periods, coastal and inland Azapa region (Chile) from the Late Archaic to the Late periods, and the Atacama Desert oases (Chile) from the Formative period to the time of European contact. Craniometric information obtained from a sample of 565 individuals from different sites of the studied regions was evaluated using methods derived from quantitative genetics and multivariate statistical analysis techniques. It is shown that during the Formative and Tiwanaku periods inhabitants of the Cochabamba valleys maintained contact with the population of northern Chile. This contact was more fluid with the people from the interior valley of Azapa than it was with the settlers of San Pedro Atacama (SPA). An important biological affinity in the Late Period between the inhabitants of the Azapa valley and the late SPA groups is also examined. The Late-Inca Catarpe SPA sample shows a broad genetic variability shared with the majority of the groups studied. The results reaffirm the differences between the coastal and interior Azapa valley groups and strengthen the hypothesis of two pathways to populating the south central Andean area. The divergence observed among subpopulations can be explained by the spatiotemporal dispersion between them, genetic drift dispersion compensated by the action of gene flow, and cultural norms that regulate within group mating. PMID:25234247

  4. The south-central United States magnetic anomaly

    Science.gov (United States)

    Starich, P. J.; Hinze, W. J.; Braile, L. W.

    1985-01-01

    A positive magnetic anomaly, which dominates the MAGSAT scalar field over the south-central United States, results from the superposition of magnetic effects from several geologic sources and tectonic structures in the crust. The highly magnetic basement rocks of this region show good correlation with increased crustal thickness, above average crustal velocity and predominantly negative free-air gravity anomalies, all of which are useful constraints for modeling the magnetic sources. The positive anomaly is composed of two primary elements. The western-most segment is related to middle Proterozoic granite intrusions, rhyolite flows and interspersed metamorphic basement rocks in the Texas panhandle and eastern New Mexico. The anomaly and the magnetic crust are bounded to the west by the north-south striking Rio Grande Rift. The anomaly extends eastward over the Grenville age basement rocks of central Texas, and is terminated to the south and east by the buried extension of the Ouachita System. The northern segment of the anomaly extends eastward across Oklahoma and Arkansas to the Mississippi Embayment. It corresponds to a general positive magnetic region associated with the Wichita Mountains igneous complex in south-central Oklahoma and 1.2 to 1.5 Ga. felsic terrane to the north.

  5. Strategies for improving thermal performance and visual comfort in office buildings of Central Chile

    OpenAIRE

    Bustamante Gómez, Waldo; Encinas Pino, Felipe; Pino, Alan; Otarola, Roberto; PLEA 2011 - 27th International Conference on Passive and Low Energy Architecture: Architecture & Sustainable Development

    2011-01-01

    Overheating, high cooling energy demand and glare are recurrent problems in office buildings in Santiago and Valparaíso, Chile. Santiago (33°S) presents a Mediterranean climate, with a high temperature oscillation between day and night during cooling period. Valparaiso (33°S), by the coast, shows lower temperature fluctuation compared with Santiago. In order to evaluate impact on thermal and lighting performance of office buildings of these cities, a sensitivity study has been made. Variation...

  6. Central Energy System Modernization at Fort Jackson, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Daryl R.; Chvala, William D.; Dirks, James A.

    2006-11-29

    An evaluation of technology options was conducted for the central energy systems at Fort Jackson, South Carolina. There were two objectives in conducting this study. From a broader viewpoint, the Army would like to develop a systematic approach to management of its central energy systems and selected Fort Jackson for this ''pilot'' study for a prospective Central Energy System Modernization Program. From a site-specific perspective, the objective was to identify the lowest life-cycle cost energy supply option(s) at Fort Jackson for buildings currently served by central boilers and chillers. This study was co-funded by the Army's Southeast Region and the U.S. Department of Energy's Federal Energy Management Program.

  7. A new species of Phymaturus of the P. mallimaccii Group from the Andes of central Chile (Iguania: Liolaemidae

    Directory of Open Access Journals (Sweden)

    Jaime Troncoso-Palacios

    2014-08-01

    Full Text Available A new species of Phymaturus from the Provincia Mountain in the San Ramón Mountains in the Metropolitan Region of Chile is described. It is a member of the P. palluma Group and the P. mallimaccii subgroup. The new species can be distinguished from other members of the P. mallimaccii subgroup by having a highly fragmented subocular scale (4 or 5, a preocular scale that is smaller than the canthal, males having a olive dorsum with a diffuse pattern of light bands on the paravertebral fields and a light triangle between the shoulders, which has the apex of the triangle oriented toward the snout. The distribution of new species lies south of that of other members of the P. mallimaccii subgroup, from which it is completely isolated. The low abundance of the new species is noteworthy. Information about the natural history of the lizard is provided and some aspects of unnamed populations of Chilean Phymaturus are discussed.

  8. Central Coast Region South District Basin Planning & Habitat Mapping Project

    OpenAIRE

    Watson, Jessica; Casagrande, Julie; Watson, Fred

    2008-01-01

    This is a report to the California Department of Fish and Game. Between 2003 and 2008, the Foundation of CSUMB produced fish habitat maps and GIS layers for CDFG based on CDFG field data. This report describes the data entry, mapping, and website construction procedures associated with the project. Included are the maps that have been constructed. This report marks the completion of the Central Coast region South District Basin Planning and Habitat Mapping Project. (Document contains 40 pages)

  9. Observations of TEC Depletions in South and Central America

    Science.gov (United States)

    Valladares, C. E.; Sheehan, R. E.; Pradipta, R.

    2014-12-01

    TEC values gathered with several networks of GPS receivers, which operated in South and Central America and the Caribbean region between 2010 and 2013, have been used to investigate the characteristics and morphology of TEC depletions that develop at these locations. In South America the TEC depletions are associated with low-latitude plasma bubbles. In Central America and the Caribbean region, we found that TEC depletions that occur during magnetically active conditions (Kp > 5o), persist for very long periods and sometimes remain even during afternoon hours. During quiet magnetic conditions, TEC depletions occur around the June solstice in Central America and during the December solstice in the Southern part of South America. We have also studied possible links between mid-latitude depletions and the formation of plasma bubbles at low latitudes. In addition, TEC measurements from North America have been utilized to determine the poleward extension of the mid-latitude depletions. These depletions do not appear to be related to auroral plasma processes or to storm enhanced densities (SED). We are studying the possibility that their initiation process is associated with the disturbance dynamo or the prompt penetrating electric field that develop during storm conditions.

  10. Composición, estructura y flujo energético del meiobentos frente a Chile central Composition, structure and energy flux of the meiobenthos off central Chile

    Directory of Open Access Journals (Sweden)

    JAVIER SELLANES

    2003-09-01

    Full Text Available Se estudió la estructura de la meiofauna metazoaria (a nivel de grandes grupos taxonómicos y su rol en el flujo de energía en el subsistema bentónico frente a Concepción (~3630' S. Las muestras se recolectaron en mayo y noviembre de 1997 y mayo de 1998 en cinco sitios correspondientes a: interior de la Bahía de Concepción (28 m, boca de la bahía (35 m, plataforma interior (64 m, plataforma intermedia (88 m y plataforma externa (120 m. El periodo de estudio coincidió con el evento El Niño 1997-1998 (EN. El meiobentos resultó ser poco diverso a nivel de grandes grupos, pero con abundancias y biomasas moderadas a altas, en comparación con los valores promedio reportados en la literatura para el sublitoral fangoso. Nematoda fue el grupo dominante, con más de un 95 % (10³­10(4 ind 10 cm­2 de la densidad total, seguidos por Copepoda y Polychaeta. Las mayores abundancias y biomasas totales se encontraron siempre en la boca de la bahía, seguida de su parte interior y de la plataforma interior, mientras que los menores valores se ubicaron en la plataforma intermedia y externa. Frente a Concepción el meiobentos juega un importante rol en el flujo de energía a través del subsistema bentónico. Se estimó que estos organismos podrían estar remineralizando y/o convirtiendo a biomasa hasta un 36 y 45 % del carbono orgánico que llega desde la columna de agua a los sedimentos en el centro y en la boca de la bahía, respectivamente.The general objective of this study was to determine the structure of metazoan meiofauna (at a high taxonomic level and to estimate its role in the energy flux of the benthic sub-system off Concepción, Chile (~3630' S. Samples were collected in May and November 1997 and May 1998 at five sites located at the: inner Bay of Concepción (28 m, bay-mouth (35 m, inner-shelf (64 m, mid-shelf (88 m and outer-shelf (120 m. The study period coincided with the El Niño 1997-1998 (EN event. The diversity of the meiobenthos

  11. Distribution of burrowing owls in east-central South Dakota

    Science.gov (United States)

    Shaffer, Jill A; Thiele, Jason P.

    2013-01-01

    Western burrowing owl (Athene cunicularia hypugaea) populations have declined across much of western North America, particularly at the northern and eastern edges of the species’ breeding range (Martell et al. 2001, Murphy et al. 2001, Shyry et al. 2001, Skeel et al. 2001, Klute et al. 2003). In South Dakota, the burrowing owl is a summer resident that historically was relatively common throughout the state, but its range has decreased in recent decades, especially in the eastern half of the state (Whitney et al. 1978, South Dakota Ornithologists’ Union [SDOU] 1991, Peterson 1995). Tallman et al. (2002) described the species as uncommon to locally common in western South Dakota, uncommon in the north-central part of the state, and casual (i.e., not within the species’ normal range, but with 3–10 records in the past 10 years) elsewhere in the eastern half. The burrowing owl is a Species of Greatest Conservation Need (South Dakota Department of Game, Fish and Parks [SDGFP] 2006) and a Level I Priority Species in South Dakota (Bakker 2005).

  12. Social and economic factors of chile de agua (Capsicum Annum L. in three municipalities of the Central Valley in Oaxaca

    Directory of Open Access Journals (Sweden)

    María de los Ángeles Rodríguez Mendoza

    2013-01-01

    Full Text Available This issue was carried out in the municipalities of San Pablo Huixtepec, San Sebastián Abasolo and Culiapan of Guerrero as part of the Central Valleys of Oaxaca, Mexico. We studied the production system of Agua Chile, using the technique of structured interview,information was obtained that allowed us to determine and meet the current models of socio-economic benefits in the form of productionof this vegetable. The importance of this study is that the chile de agua despite being a highly profitable crop has been little studied, so it is not known the extent that can have, there are markets that offer potentially greater benefits to farmers, therefore it is important to know the current situation of farmers in order to provide alternatives to improve their economic situation. The results indicate that according to the practices of peasant production and the low level of technology that includes the type of fertilizers, agrochemicals to combat pests and diseases and low use of agricultural machinery, yields of 3.97 t ha-1 allow total revenues are higher than the costs of production. Besides the existence of limited marketing networks (primarily in local markets and in the Oaxaca city, is a competitive crop in terms of profitability for finance of small production units and furthermore, it is growing factor relevant food security of farming families.

  13. Geographic variation in diversity of wave exposed rocky intertidal communities along central Chile Variación geográfica de la biodiversidad en hábitats intermareales rocosos de Chile central

    Directory of Open Access Journals (Sweden)

    BERNARDO R BROITMAN

    2011-03-01

    Full Text Available Along the coast of central Chile, geographic trends of diversity have been inferred from literature compilations and museum collections based on species range limits for some taxonomic groups. However, spatially-intensive field-based assessments of macrobenthic species richness are largely missing. Over the course of a multiyear study (1998-2005, we characterized latitudinal patterns of rocky intertidal diversity at 18 sites along the coast of central Chile (29-36° S. At each site, the number of sessile and mobile macrobenthic species was quantified in 0.25 m² quadrats. Two estimators of local (alpha diversity were used: observed local species richness, calculated from the asymptote of a species-rarefaction curve, and the Chao2 index, which takes into account the effect of rare species on estimates of local richness. We identified a total of 71 species belonging to 66 genera for a total of 86 taxa. The most diverse groups were herbivorous mollusks (27 taxa and macroalgae (43 taxa. Diversity showed a complex spatial pattern with areas of high species richness interspersed with areas of low richness. In accordance with previous work, we found no trend in the number of herbivorous mollusks and an inverse and significant latitudinal gradient in the number of algal species. Our results highlight the need for taxonomically diverse assessments of biodiversity of the dominant taxa that conform intertidal communities.A lo largo de la costa de Chile central, los patrones geográficos de diversidad han sido inferidos a partir de revisiones literarias y colecciones de museos para algunos grupos taxonómicos. Sin embargo, aun no contamos con una evaluación integral, y en terreno, de la riqueza de especies macrobentónicas intermareales. En un estudio de largo plazo conducido entre 1998 y 2005 caracterizamos los patrones latitudinales en la biodiversidad del intermareal rocoso en 18 sitios a lo largo de la costa de Chile central (29-36° S. En cada sitio

  14. Mycotrophy in Gilliesieae, a threatened and poorly known tribe of Alliaceae from central Chile Micotrofía en Gilliesieae, una tribu amenazada y poco conocida de Alliaceae de Chile central

    Directory of Open Access Journals (Sweden)

    GUSTAVO A TORRES-MELLADO

    2012-06-01

    Full Text Available The five known genera of Gilliesieae have their diversity center in the Mediterranean zone of central Chile, where many of their habitats are threatened by urban expansion, industrial and agroforestry activities, as well as other anthropogenic impacts. Very little is known about the biology of these particular geophytes, the majority of which currently have either vulnerable or endangered status, mainly due to their dispersed and small populations generally associated to remnants of native vegetation. As mycorrhizal associations are essential for soil resource acquisition and stress mitigation in most plants, our objective was to assess the hitherto unknown mycotrophic status of ten species of Gilliesieae from central Chile by qualitative and quantitative assessment of intraradical fungal structures. All sampled genera (Gethyum, Gilliesia, Miersia, Solaria, Speea showed regular presence of arbuscular mycorrhiza, while other mycorrhizal or putatively mutualistic associations, like dark septate endophytes, were practically absent. Mycorrhizal colonization of fine roots reached a mean of ca. 45 % across all examined taxa, with highly variable values ranging from 9 % to 82 % in Miersia tenuiseta and Gilliesia curicana, respectively. The high level of mycorrhization indicates that arbuscular mycorrhiza should be considered for conservation strategies of threatened species or biotechnological use in plant propagation. The main future task is the identification of the associated fungal taxa.Los cinco géneros conocidos de Gilliesieae tienen su centro de diversidad en la zona mediterránea de Chile central, donde muchos de sus hábitats están amenazados por la expansión urbana, actividades industriales y agroforestales, así como otros impactos antropogénicos. Se sabe muy poco sobre la biología de estas particulares geófitas, que en la actualidad tienen en su mayoría estatus de vulnerable o en peligro de extinción, debido a sus poblaciones

  15. Latencia y banco de semillas en plantas de la región mediterránea de Chile central Seed bank and dormancy in plants of the Mediterranean region of central Chile

    Directory of Open Access Journals (Sweden)

    JAVIER A. FIGUEROA

    2004-03-01

    Full Text Available Los bancos de semillas en las regiones mediterráneas presentan rasgos particulares que los distinguen de bancos de otras regiones del mundo. El banco de semillas es concentración de propágulos viables enterrados en el suelo por períodos variables de tiempo. Los bancos de semillas del matorral de Chile central son principalmente transitorios y funcionalmente semejantes a los bancos presentes en otros ecosistemas mediterráneos no perturbados por fuego, a excepción de Australia. El banco transitorio es aquel formado por semillas que permanecen viables en los horizontes superiores del suelo por no más de 1 año después de la dispersión. En el matorral de Chile central, en los horizontes superiores del suelo, se encuentra una de las densidades de semillas de hierbas más altas de las regiones mediterráneas. Una gran proporción de esta reserva está constituida por semillas sin latencia, fácilmente germinables, especialmente pastos anuales que germinan en otoño. Con respecto a los mecanismos de latencia de las semillas del banco transitorio responsables del almacenamiento de las semillas en el suelo, nuestra revisión bibliográfica reveló los siguientes principales síndromes de germinación: (1 especies con semillas que deben ser estratificadas en frío debido a la presencia de latencia fisiológica (principalmente hierbas introducidas; (2 especies con semillas que deben ser escarificadas con ácidos o procedimientos mecánicos debido a la presencia de latencia física (principalmente especies leñosas nativas; (3 especies con latencia fisiológica que necesitan de estratificación cálida para activar la germinación (hierbas nativas e introducidas. Estos síndromes provocan que la época de germinación en Chile central esté situada entre otoño e inicio de la primavera. Además, no hay referencias sobre la presencia de algún síndrome esporádico de germinación para los componentes de un banco de semillas permanente. Proponemos

  16. Pseudoterranova cattani sp. nov. (Ascaridoidea: Anisakidae, a parasite of the South American sea lion Otaria byronia De Blainville from Chile Pseudoterranova cattani sp. nov. (Ascaridoidea: Anisakidae, un parásito del lobo marino común Otaria byronia De Blainville en Chile

    Directory of Open Access Journals (Sweden)

    MARIO GEORGE-NASCIMENTO

    2000-03-01

    Full Text Available The parasitic nematode Pseudoterranova cattani sp. nov. is described from the stomach of the South American sea lion Otaria byronia De Blainville, sampled along the coastline off central-south Chile, between 1980 and 1997. The adult and larvae of this species have been previously reported in the Southeastern Pacific Ocean as Phocanema decipiens Myers. Major differences with species from the North Atlantic and Northwest Pacific are based on the body size, number, distance and size of caudal pillaeSe describe al nemátodo parásito Pseudoterranova cattani sp. nov. encontrado en el estómago del lobo marino común Otaria byronia De Blainville, en muestras tomadas entre 1980 y 1997, a lo largo de la costa del centro-sur de Chile. Las larvas y adultos de esta especie han sido registrados en el océano Pacífico sudoriental como Phocanema decipiens Myers. Las principales diferencias con las especies del Atlántico norte y del Pacífico noroccidental se basan en el tamaño corporal y en el número, tamaño, distancia y proporciones de las papilas caudales

  17. Regional ceramic production and distribution systems during the late intermediate ceramic period in central Chile based on NAA

    International Nuclear Information System (INIS)

    This research focused on the pre-Hispanic ceramic production and distribution systems of the Maipo region in central Chile by means of determining the concentration of the chemical elements in pottery of the Aconcagua culture (900-1450 A.D.) with instrumental neutron activation analysis (INAA). Pottery fragments from eight archaeological sites and natural clays from the study region were included. The differences in chemical composition between subsets of the sample (sites, paste group and ceramic type) were interpreted as indicators of resource and ceramic production locations as well as the imprint of the geological background. These results contributed to the understanding of the Aconcagua ceramic assemblage and helped to test some hypotheses about the Aconcagua social organization. (author)

  18. Central and South America GPS geodesy - CASA Uno

    Science.gov (United States)

    Kellogg, James N.; Dixon, Timothy H.

    1990-01-01

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

  19. A study of the energy balance and melt regime on Juncal Norte Glacier, semi-arid Andes of central Chile, using melt models of different complexity

    OpenAIRE

    Pellicciotti, Francesca; Helbing, Jakob; Rivera, Andrés; Favier, Vincent; Corripio, Javier; Araos, José; Sicart, Jean-Emmanuel; Carenzo, Marco

    2008-01-01

    We use meteorological data from two automatic weather stations (AWS) on Juncal Norte Glacier, central Chile, to investigate the glacier-climate interaction and to test ablation models of different complexity. The semi-arid Central Andes are characterized by dry summers, with precipitation close to zero, low relative humidity and intense solar radiation. We show that katabatic forcing is dominant both on the glacier tongue and in the fore field, and that low humidity and absence of clouds caus...

  20. The lower cretaceous volcanism in the coastal range of Central Chile: Geochronology and isotopic geochemistry

    International Nuclear Information System (INIS)

    Major factors involved in subduction zone magmatism are related to the melting of the underlying mantle, which can contain a component of aqueous fluid and/or melts derived from the subducting plate (e.g. Peate et al., 1997). The Chilean Pacific margin is a subduction zone, active from Early Mesozoic to now, in which the magmatic arc emplaced on the Paleozoic basement progressively migrate to the east. The western part of this arc constitutes the Coastal Range. In this work, isotopic and radiometric data from four E-W profiles along c. 500 km of the Lower Cretaceous volcanic rocks in the Coastal Range of Chile are presented. The aim of this research is to obtain a model for the genesis of this Cretaceous volcanic arc based on their isotopic signature (au)

  1. Characterization of backyard poultry production systems and disease risk in the central zone of Chile.

    Science.gov (United States)

    Hamilton-West, C; Rojas, H; Pinto, J; Orozco, J; Hervé-Claude, L P; Urcelay, S

    2012-08-01

    Backyard poultry production systems (BPS) are an important and widespread form of poultry production. There is a common perception that biosecurity standards in BPS are generally poor and BPS are usually associated with animal diseases and zoonoses. In this study BPS were identified in the vicinity of six wetlands, having these a higher risk of presenting and introducing avian diseases such as HPAI and Newcastle disease, as defined by the national veterinary services, in to Chile's main poultry production area. BPS were characterized through a field questionnaire and the main areas covered by the survey were BPS structure, biosecurity and value chain. The BPS identified in this study share most characteristics on biosecurity, poultry management and product commercialization, but it was possible to identify a certain degree of variation within and among the study sites. BPS in Chile are similar to those in other regions, with a relatively small flock size (average 37 birds), a low level of biosecurity measures and lack of poultry disease management. Management findings include that most farmers used mixed/partial confinement, with low or no biosecurity and disease control measures in place. Eggs were the main output and were used mainly for home consumption or sale at local markets. Sick birds' treatment with drugs approved for other species or for human use could represent a risk to human health, owing to the possible presence of drug residues in poultry products. Despite the different structures of the poultry sector worldwide, BPS can play a major role in disease maintenance and spread because its management conditions characteristics and the lack of animal health services adapted to these production systems. This should be an alert message to the veterinary authorities to improve coverage of veterinary assistance and surveillance activities in backyard poultry production. PMID:21752410

  2. 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

  3. Reconstruction of cryospheric changes in the Maipo and Juncal river basins, central Andes of Chile: an integrative geomorphological approach

    Science.gov (United States)

    Nussbaumer, Samuel U.; García, Juan L.; Gómez, Gabriel; Vega, Rodrigo M.; Gärtner-Roer, Isabelle; Salzmann, Nadine

    2016-04-01

    Water in the central Andes (32-38° S), a semi-arid mountainous area with elevations over 6000 m asl., is of great importance and a critical resource especially in the dry summer months. Ice bodies, such as glaciers and rock glaciers (permafrost) in the high mountains, provide a substantial part of the fresh-water resources but also for intensive economical use for the lowlands including Santiago metropolitan region, Chile. However the evolution of these ice bodies since the last deglaciation (i.e., Holocene, last ˜12,000 years), and in particular during historical times, and their feedback with climate is fairly unknown. In view of projected climate change, this is striking because it is also unknown whether these natural resources could be used as sustainable fresh-water source in the future. Within the presented project, we develop and apply an integrative geomorphologic approach to study glaciers and their long-term evolution in the central Andes of Chile. Apart from glaciers (with variable debris-coverage), rock glaciers have evolved over time as striking geomorphological landforms in this area. We combine geomorphologic mapping using remote-sensing and in-situ data with an innovative surface exposure dating technique to determine the ages of distinct moraine ridges at three study sites in watersheds of the Santiago region: Juncal Norte, Loma Larga and Nieves Negras glaciers. First results of the project are presented, including a detailed geomorphological mapping and first analysis of the landform dynamics. At all three sites, we distinguished at least three moraine systems of a Holocene putative age. These prominent moraine belts show that glaciers were at least 5 km longer than at present. Deglaciation from these ice marginal positions was gradual and complex in response to the detrital cover on the glaciers. Differences in ice thickness of the main glaciers in the respective valleys amount to about 100 m. Due to the partial, extensive debris coverage, the

  4. Conducta de forrajeo del gastrópodo Acanthina monodon Pallas, 1774 (Gastropoda: Muricidae en el intermareal rocoso de Chile central Foraging behavior of the gastropod Acanthina monodon Pallas, 1774 (Gastropoda: Muricidae in the intertidal rocky shores of central Chile

    Directory of Open Access Journals (Sweden)

    RUBÉN E. SOTO

    2004-03-01

    Full Text Available En el presente trabajo investigamos aspectos de la ecología y conducta de forrajeo de Acanthina monodon, un gastrópodo murícido que habita en el intermareal rocoso de Chile central. En terreno, estudiamos las variaciones temporales en su distribución, densidad y dieta. En el laboratorio, cuantificamos la tasa de consumo, las preferencias alimentarias, el tiempo de ingestión y la rentabilidad energética obtenida con distintos tipos de presas mediante experimentos y registros en video. Las mayores densidades de individuos de A. monodon fueron observadas en la franja intermareal cercana al nivel cero de marea. En terreno, A. monodon realiza sus actividades de forrajeo principalmente durante la noche y su dieta consistió principalmente de mitílidos (95 % y cirripedios (5 %. La composición de la dieta de A. monodon en terreno presentó variaciones temporales las cuales dependerían principalmente de cambios en la oferta de los distintos tipos de mitílidos presentes en terreno durante los dos años de muestreo. En el laboratorio, los individuos de Acanthina presentaron preferencias alimentarias significativas por el mitílido Semimytilus algosus. En general, A. monodon bajo condiciones de laboratorio presentó una conducta de forrajeo en la cual maximizó la ganancia neta de energía, mediante la selección de las especies y tamaños de presas que le retribuyen la mayor rentabilidad energéticaWe investigated the ecology and foraging behavior of Acanthina monodon, a muricid gastropod that inhabits in the intertidal rocky shores of central Chile. In the field, we studied temporal variation of their spatial distribution, density, and diet composition. While in the laboratory, we quantified the consumption rate, alimentary preferences, ingestion times and energy profitability obtained with different types of prey using experiments and video recording. High densities of A. monodon individuals were observed in the intertidal fringe near at the

  5. Presence of Arctotherium (Carnivora, Ursidae, Tremarctinae in a pre-cultural level of Baño Nuevo-1 cave (Central Patagonia, Chile

    Directory of Open Access Journals (Sweden)

    López Mendoza, P.

    2015-12-01

    Full Text Available The description of an I3 assigned to Arctotherium sp. obtained from the Baño Nuevo-1 site (Central Patagonia, Chile is presented. The finding was recovered from Layer 5 and it is associated to Macrauchenia sp., Lama guanicoe, Felidae, Camelidae, Equidae and Mylodontidae, within a sterile deposit of cultural material, dated between ca. 13.500 and 11.200 BP. Despite the fact that it is only a single specimen, such finding extends the known distribution for the genus in Chile.Se presenta la descripción de un I3 asignado a Arctotherium sp. proveniente del sitio Baño Nuevo-1 (Patagonia Central, Chile. El hallazgo fue realizado en la Capa 5 y está asociado a restos de Macrauchenia sp., Lama guanicoe, Felidae, Camelidae, Equidae y Mylodontidae dentro de un depósito estéril de material cultural, datado entre los ca. 13.500 y 11.200 años AP. Aunque se trata de un único espécimen, amplía el rango de distribución conocido para este género en Chile.

  6. Arc-oblique fault systems: their role in the Cenozoic structural evolution and metallogenesis of the Andes of central Chile

    Science.gov (United States)

    Piquer, Jose; Berry, Ron F.; Scott, Robert J.; Cooke, David R.

    2016-08-01

    The evolution of the Main Cordillera of Central Chile is characterized by the formation and subsequent inversion of an intra-arc volcano-tectonic basin. The world's largest porphyry Cu-Mo deposits were emplaced during basin inversion. Statistically, the area is dominated by NE- and NW-striking faults, oblique to the N-striking inverted basin-margin faults and to the axis of Cenozoic magmatism. This structural pattern is interpreted to reflect the architecture of the pre-Andean basement. Stratigraphic correlations, syn-extensional deposits and kinematic criteria on fault surfaces show several arc-oblique structures were active as normal faults at different stages of basin evolution. The geometry of syn-tectonic hydrothermal mineral fibers, in turn, demonstrates that most of these structures were reactivated as strike-slip ± reverse faults during the middle Miocene - early Pliocene. Fault reactivation age is constrained by 40Ar/39Ar dating of hydrothermal minerals deposited during fault slip. The abundance and distribution of these minerals indicates fault-controlled hydrothermal fluid flow was widespread during basin inversion. Fault reactivation occurred under a transpressive regime with E- to ENE-directed shortening, and was concentrated around major plutons and hydrothermal centers. At the margins of the former intra-arc basin, deformation was largely accommodated by reverse faulting, whereas in its central part strike-slip faulting was predominant.

  7. Patterns of turnover and floristic similarity show a non-random distribution of naturalized flora in Chile, South America Patrones de recambio y similitud florística muestran una distribución no aleatoria de la flora naturalizada en Chile, Sudamérica

    Directory of Open Access Journals (Sweden)

    SERGIO A CASTRO

    2008-03-01

    Full Text Available The current geographical distribution of alien species could be informative of processes involved in the biological invasions facilitated by humans. Because environmental and anthropic factors affect the geographic distribution of alien plants, we hypothesize that naturalized plants have a non-random distribution along extensive geographical ranges. On the basis of a complete and updated database of naturalized plants in Chile, we analyzed their turnover and floristic similarities among regions that encompass a wide latitudinal gradient in South America. Using Moran's index and Mantel's test we characterized the spatial auto-correlation (regional aggregation and the effect of geographical distance on the index values. Additionally, we used clustering methods and resampling procedures to detect plant assemblages at regional level. Whittaker's index displayed a positive tilt, increasing according to geographical distance and reaching a plateau; conversely, Jaccard's index was negatively associated with geographical distance. Removing the effect of distance, both Whittaker's and Jaccard's values showed no significant trends. Multivariate analysis combined with resampling procedures revealed the existence of three distinctive plant clusters: Northernmost Chile, Central-southern Chile, and Southernmost Chile. These clusters are characterized by naturalized plants that are not present in the others. Based on this evidence, we conclude that the set of naturalized plants in Chile exhibits a non-random geographical distribution, displaying an ordered geographical pattern across regions (latitude. We discuss the role of the environmental variables (climate, latitude and land use post-European colonization as factors in the distributional patterns here documentedLa distribución geográfica actual de especies exóticas puede ser informativa de los procesos involucrados en las invasiones biológicas facilitadas por humanos. Debido a que los factores

  8. An integrated framework to assess adaptation options to climate change impacts in an irrigated basin in Central North Chile

    Science.gov (United States)

    Vicuna, S.; Melo, O.; Meza, F. J.; Alvarez, P.; Maureira, F.; Sanchez, A.; Tapia, A.; Cortes, M.; Dale, L. L.

    2013-12-01

    Future climate conditions could potentially affect water supply and demand on water basins throughout the world but especially on snowmelt-driven agriculture oriented basins that can be found throughout central Chile. Increasing temperature and reducing precipitation will affect both the magnitude and timing of water supply this part of the world. Different adaptation strategies could be implemented to reduce the impacts of such scenarios. Some could be incorporated as planned policies decided at the basin or Water Use Organization levels. Examples include changing large scale irrigation infrastructure (reservoirs and main channels) either physically or its operation. Complementing these strategies it is reasonable to think that at a disaggregated level, farmers would also react (adapt) to these new conditions using a mix of options to either modify their patterns of consumption (irrigation efficiency, crop mix, crop area reduction), increase their ability to access new sources of water (groundwater, water markets) or finally compensate their expected losses (insurance). We present a modeling framework developed to represent these issues using as a case study the Limarí basin located in Central Chile. This basin is a renowned example of how the development of reservoirs and irrigation infrastructure can reduce climate vulnerabilities allowing the economic development of a basin. Farmers in this basin tackle climate variability by adopting different strategies that depend first on the reservoir water volume allocation rule, on the type and size of investment they have at their farms and finally their potential access to water markets and other water supplies options. The framework developed can be used to study these strategies under current and future climate scenarios. The cornerstone of the framework is an hydrology and water resources model developed on the WEAP platform. This model is able to reproduce the large scale hydrologic features of the basin such as

  9. Characterization of copper-resistant bacteria and bacterial communities from copper-polluted agricultural soils of central Chile

    Directory of Open Access Journals (Sweden)

    Altimira Fabiola

    2012-09-01

    Full Text Available Abstract Background Copper mining has led to Cu pollution in agricultural soils. In this report, the effects of Cu pollution on bacterial communities of agricultural soils from Valparaiso region, central Chile, were studied. Denaturing gradient gel electrophoresis (DGGE of the 16S rRNA genes was used for the characterization of bacterial communities from Cu-polluted and non-polluted soils. Cu-resistant bacterial strains were isolated from Cu-polluted soils and characterized. Results DGGE showed a similar high number of bands and banding pattern of the bacterial communities from Cu-polluted and non-polluted soils. The presence of copA genes encoding the multi-copper oxidase that confers Cu-resistance in bacteria was detected by PCR in metagenomic DNA from the three Cu-polluted soils, but not in the non-polluted soil. The number of Cu-tolerant heterotrophic cultivable bacteria was significantly higher in Cu-polluted soils than in the non-polluted soil. Ninety two Cu-resistant bacterial strains were isolated from three Cu-polluted agricultural soils. Five isolated strains showed high resistance to copper (MIC ranged from 3.1 to 4.7 mM and also resistance to other heavy metals. 16S rRNA gene sequence analyses indicate that these isolates belong to the genera Sphingomonas, Stenotrophomonas and Arthrobacter. The Sphingomonas sp. strains O12, A32 and A55 and Stenotrophomonas sp. C21 possess plasmids containing the Cu-resistance copA genes. Arthrobacter sp. O4 possesses the copA gene, but plasmids were not detected in this strain. The amino acid sequences of CopA from Sphingomonas isolates (O12, A32 and A55, Stenotrophomonas strain (C21 and Arthrobacter strain (O4 are closely related to CopA from Sphingomonas, Stenotrophomonas and Arthrobacter strains, respectively. Conclusions This study suggests that bacterial communities of agricultural soils from central Chile exposed to long-term Cu-pollution have been adapted by acquiring Cu genetic determinants

  10. PLAGUICIDAS ORGANOCLORADOS PERSISTENTES EN SEDIMENTOS DE TRES LAGOS COSTEROS Y UN LAGO ANDINO DE CHILE CENTRAL

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    RICARDO BARRAL

    2001-06-01

    Full Text Available Se evaluó la presencia y distribución de los compuestos orgánicos persistentes (COPs en núcleos de sedimentos de los lagos Chica y Grande de San Pedro, Lleu-Lleu e Icalma. Los compuestos fueron extraídos mediante sistema soxhlet con solvente n-hexano, la identificación y cuantificación, de estos, se realizó por cromatografía gaseosa con detector de captura de electrones de 63Ni. Se realizó un análisis estadístico de componentes principales (ACP y Correlación de Pearson. Los plaguicidas identificados en los sedimentos fueron: a-HCH, g-HCH, Heptacloro, Aldrin, Endrin, pp´-DDT, pp'-DDE y pp'-DDD. Los resultados indican variaciones en la distribución y concentración de los COPs, al comparar los lagos urbanos con los lagos prístinos. Destaca la presencia de pp'-DDE (rango: b.n.d- 1.68 ng g-1 peso seco y pp'-DDT (rango: b.n.d- 0.89 ng g-1 peso seco en tres de los cuatro cuerpos de agua analizados. El análisis estadístico identificó correlaciones significativas entre el pp'-DDE y pp'-DDD. No se detectaron correlaciones entre el pp'-DDT y sus metabolitos. El ACP permitió agrupar algunos compuestos orgánicos en función de sus concentraciones y degradación a través del tiempo. Se concluye que Laguna Chica de San Pedro presentó las concentraciones más altas de COPs, las cuales son bajas al ser comparadas con concentraciones detectadas en áreas limpias del Sur de ChileWe have measured concentrations and distribution of Persistent Organic Compounds (POC in sediment cores from four Chilean lakes: Laguna Chica de San Pedro, Laguna Grande de San Pedro, Lleu-lleu, and Icalma. The organochlorine compounds were extracted with n-hexane in a soxhlet system and then identified and quantified by gas chromatography using a 63 Ni Electron Capture Detector. Statistical analyses were performed using a Principal Components Analysis (PCA and the Pearson Correlation. The following pesticides were identified in the sediments: a-HCH, Lindane

  11. Satellite-measured interannual variability of turbid river plumes off central-southern Chile: Spatial patterns and the influence of climate variability

    Science.gov (United States)

    Saldías, Gonzalo S.; Largier, John L.; Mendes, Renato; Pérez-Santos, Iván; Vargas, Cristian A.; Sobarzo, Marcus

    2016-08-01

    Ocean color imagery from MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the Aqua platform is used to characterize the interannual variability of turbid river plumes off central-southern Chile. Emphasis is placed on the influence of climate fluctuations, namely El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Antarctic Oscillation (AAO). Additional satellite data on wind, boat-based hydrographic profiles, and regional climate indices are used to identify the influence of climate variability on the generation of anomalous turbid river plumes. The evolution of salinity at a coastal station on the 90 m isobath between the Itata and Biobío Rivers shows a freshwater surface layer with salinity < 32.5 and 5-10 m thick during major plume events in 2002, 2005 and 2006. Surface salinity minima are correlated with peaks in turbidy from the normalized water leaving radiance at 555 nm (nLw(555)), both representing turbid river plumes. EOF analysis reveals that major turbid plume events occurred primarily during warm phases of the ENSO and PDO, and negative phases of the AAO, when storm tracks are further north. Anomalously large turbid plumes extend long distances offshore (∼ 70-80 km), and individual plumes coalesce into a continuous plume along the coast that covers the entire continental shelf. Season-specific correlation analyses reveal an increased influence of the AAO on river plumes south of Punta Lavapié in spring-summer (negative correlation). North of this major cape, ENSO and PDO indices have a dominant influence on plumes with positive correlations with the nLw(555) signal in winter (and negative in summer). We discuss the biogeochemical implications of plume events and the importance of long-term and high-resolution ocean color observations for studying the temporal evolution of river plumes.

  12. Transition towards a more environmentally sustainable biodiesel in South America: The case of Chile

    International Nuclear Information System (INIS)

    Highlights: ► Rapeseed biodiesel accounts for a 40% GHG emissions savings compared to fossil diesel. ► Biodiesel has greater impacts than fossil diesel in 7 of the 13 indicators evaluated. ► Agricultural stage cause the greatest impacts in biodiesel pathway. ► A production strategy involving low-impact or renewable resources should be used. ► Use of livestock manure as organic fertilizer presents the best environmental profile. -- Abstract: This study uses a site-specific life cycle assessment (LCA) to evaluate the environmental profile and energy and water demand of potential production options for rapeseed biodiesel in Chile. The first step is the analysis of the biodiesel supply chain in a standard scenario, associated with the most likely production conditions. The second step is the evaluation of the following alternative scenarios related to a production strategy involving low-impact or renewable resources: (1) Addition of livestock manure as organic fertilizer, (2) Use of degraded grassland, (3) Biodiesel transport by rail, and (4) Use of forest residues for industrial steam. The results show that the biodiesel in the standard scenario has less environmental impacts than fossil diesel in 4 of the 13 indicators evaluated. The rapeseed production is the stage with the highest contribution to impacts. The scenario 1 presents the best environmental profile. The scenario 2 reduces the greenhouse gas emissions of biodiesel. The scenarios 3 and 4 moderately improve the profile of the biofuel. The four situations could be implemented in the short term, but should be backed up by economic and social studies.

  13. Radiometric dating of the Horrsjoe granite, south central Sweden

    International Nuclear Information System (INIS)

    U-Pb analyses from the Horrsjoe granite, south central Sweden, give an upper intercept with concordia of 1850 +8-7Ma (1 sigma). The Horrsjoe granite accordingly belongs to the synkinematic Svecokarelian intrusions. The zircons have no visible cores. Their positions on discordia are reversed in relation to the normal case, the smallest crystals having less than half the uranium content of the largest. This may be due to uranium loss caused by superimposed events of ser- and postorogenic Svecokarelian magmatism in the area. However, a recalculation with the new U-Pb systematics of Wickman (Wickman, F.E., 1983: Uranium-lead isotope systematics: The case of crystals with discrete cores. Lithos 16) yields an age of 1946 Ma. The age of 1850 Ma is accordingly a minimum age. (Authors)

  14. Natural phenomena hazards, Hanford Site, south central Washington

    Energy Technology Data Exchange (ETDEWEB)

    Tallman, A.M.

    1996-04-16

    This document presents the natural phenomena hazard (NPH) loads for use in implementing DOE Order 5480.28, Natural Phenomena Hazards Mitigation, at the Hanford Site in south-central Washington State. The purpose of this document is twofold: (1) summarize the NPH that are important to the design and evaluation of structures, systems, and components at the Hanford Site; (2) develop the appropriate natural phenomena loads for use in the implementation of DOE Order 5480.28. The supporting standards, DOE-STD-1020-94, Natural Phenomena Hazards Design and Evaluation Criteria for Department of Energy Facilities (DOE 1994a); DOE-STD-1022-94, Natural Phenomena Hazards Site Characteristics Criteria (DOE 1994b); and DOE-STD-1023-95, Natural Phenomena Hazards Assessment Criteria (DOE 1995) are the basis for developing the NPH loads.

  15. Natural phenomena hazards, Hanford Site, south central Washington

    International Nuclear Information System (INIS)

    This document presents the natural phenomena hazard (NPH) loads for use in implementing DOE Order 5480.28, Natural Phenomena Hazards Mitigation, at the Hanford Site in south-central Washington State. The purpose of this document is twofold: (1) summarize the NPH that are important to the design and evaluation of structures, systems, and components at the Hanford Site; (2) develop the appropriate natural phenomena loads for use in the implementation of DOE Order 5480.28. The supporting standards, DOE-STD-1020-94, Natural Phenomena Hazards Design and Evaluation Criteria for Department of Energy Facilities (DOE 1994a); DOE-STD-1022-94, Natural Phenomena Hazards Site Characteristics Criteria (DOE 1994b); and DOE-STD-1023-95, Natural Phenomena Hazards Assessment Criteria (DOE 1995) are the basis for developing the NPH loads

  16. Pluri-decadal (1955–2014) evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S)

    OpenAIRE

    Monnier, S.; C. Kinnard

    2016-01-01

    This study deals with relationships between debris-covered glaciers and rock glaciers in the central Andes of Chile. Three glacier–rock glacier transitional landforms are investigated over the last decades in order to highlight and question the significance of their landscape evolution and dynamics. We use series of historical air photos and Geoeye satellite images together with common remote sensing operations including imagery orthorectification, digital elevation model generation, an...

  17. Food web and fish stock changes in central Chile: comparing the roles of jumbo squid (Dosidicus gigas) predation, the environment, and fisheries

    Science.gov (United States)

    Neira, Sergio; Arancibia, Hugo

    2013-10-01

    We analyzed recent food web and fish stock changes in the central Chile marine ecosystem, comparing the roles of jumbo squid (Dosidicus gigas) as predator, the environment, and fishing. To accomplish this we used food web modeling and the Ecopath with Ecosim software (EwE). The principal fish stocks have experienced wide decadal fluctuations in the past 30 years, including stock collapses of horse mackerel (Trachurus murphyi) and hake (Merluccius gayi), and there was a large influx of jumbo squid during the mid-2000s. We used two EwE models representing the food web off central Chile to test the hypothesis that predation by jumbo squid has been significant in explaining the dynamics of the main fishing resources and other species in the study area. Results indicate that predation by jumbo squid on fish stocks is lower than that of other predators (e.g. hake) and the fishery. Long-term fluctuations (1978-2004) in the biomass of the main fish stocks (as well as other components of the food web) seem to be related to fishing and to variation in primary production, rather than to predation by jumbo squid alone. Jumbo squid seems to play a role as predator rather than prey in the system, but its impacts are low when compared with the impacts of other predators and fishing. Therefore, we conclude that jumbo squid predation on its prey was not the primary force behind the collapse of important fish stocks off central Chile. Future efforts should be directed to better understanding factors that trigger sudden increases in jumbo squid abundance off central Chile, as well as modeling its trophic impacts.

  18. Community response of zooplankton to oceanographic changes (2002-2012) in the central/southern upwelling system of Chile

    Science.gov (United States)

    Medellín-Mora, Johanna; Escribano, Ruben; Schneider, Wolfgang

    2016-03-01

    A 10-year time series (2002-2012) at Station 18 off central/southern Chile allowed us to study variations in zooplankton along with interannual variability and trends in oceanographic conditions. We used an automated analysis program (ZooImage) to assess changes in the mesozooplankton size structure and the composition of the taxa throughout the entire community. Oceanographic conditions changed over the decade: the water column became less stratified, more saline, and colder; the mixed layer deepened; and the oxygen minimum zone became shallower during the second half of the time series (2008-2012) in comparison with the first period (2002-2007). Both the size structure and composition of the zooplankton were significantly associated with oceanographic changes. Taxonomic and size diversity of the zooplankton community increased to the more recent period. For the second period, small sized copepods (1.5 mm) and medium size copepods (1-1.5 mm), whereas euphausiids, decapod larvae, appendicularian and ostracods increased their abundance during the second period. These findings indicated that the zooplankton community structure in this eastern boundary ecosystem was strongly influenced by variability of the upwelling process. Thus, climate-induced forcing of upwelling trends can alter the zooplankton community in this highly productive region with potential consequences for the ecosystem food web.

  19. Interannual variations in the hatching pattern, larval growth and otolith size of a sand-dwelling fish from central Chile

    Science.gov (United States)

    Rodríguez-Valentino, Camilo; Landaeta, Mauricio F.; Castillo-Hidalgo, Gissella; Bustos, Claudia A.; Plaza, Guido; Ojeda, F. Patricio

    2015-09-01

    The interannual variation (2010-2013) of larval abundance, growth and hatching patterns of the Chilean sand stargazer Sindoscopus australis (Pisces: Dactyloscopidae) was investigated through otolith microstructure analysis from samples collected nearshore (<500 m from shore) during austral late winter-early spring off El Quisco bay, central Chile. In the studied period, the abundance of larval stages in the plankton samples varied from 2.2 to 259.3 ind. 1000 m-3; larval abundance was similar between 2010 and 2011, and between 2012 and 2013, but increased significantly from 2011 to 2012. The estimated growth rates increased twice, from 0.09 to 0.21 mm day-1, between 2011 and 2013. Additionally, otolith size (radius, perimeter and area), related to body length of larvae, significantly decreased from 2010 to 2012, but increases significantly in 2013. Although the mean values of microincrement widths of sagitta otoliths were similar between 2010 and 2011 (around 0.6-0.7 μm), the interindividual variability increases in 2011 and 2013, suggesting large environmental variability experienced by larvae during these years. Finally, the hatching pattern of S. australis changed significantly from semi-lunar to lunar cycle after 2012.

  20. Large scale hydrogen production from wind energy in the Magallanes area for consumption in the central zone of Chile

    International Nuclear Information System (INIS)

    The energy proposal of this research suggests the use of places with abundant wind resources for the production of H2 on a large scale to be transported and used in the central zone of Chile with the purpose of diversifying the country's energy matrix in order to decrease its dependence on fossil fuels, increase its autonomy, and cover the future increases in energy demand. This research showed that the load factor of the proposed wind park reaches a value of 54.5%, putting in evidence the excellent wind conditions of the zone. This implies that the cost of the electricity produced by the wind park located in the Chilean Patagonia would have a cost of 0.0213 US$ kWh-1 in the year 2030. The low prices of the electricity obtained from the park, thanks to the economy of scale and the huge wind potential, represent a very attractive scenario for the production of H2 in the future. The study concludes that by the year 2030 the cost of the H2 generated in Magallanes and transported to the port of Quinteros would be 18.36 US$ MBTU-1, while by that time the cost of oil would be about 17.241 US$ MBTU-1, a situation that places H2 in a very competitive position as a fuel. (author)

  1. Breeding distribution and abundance of seabirds on islands off north-central Chile Distribución reproductiva y abundancia de aves marinas en islas del norte y centro de Chile

    OpenAIRE

    ALEJANDRO SIMEONE; GUILLERMO LARA-JORQUERA; MARIANO BERNAL; STEFAN GARTHE; FELIPE SEPÚLVEDA; ROBERTO VILLABLANCA; URSULA ELLENBERG; MACARENA CONTRERAS; JULIETA MUÑOZ; TAMARA PINCE

    2003-01-01

    Between 1999 and 2003 we collected information on the breeding distribution and abundance of 12 seabird species occurring on nine islands off the coasts of north and central Chile (27°-33°S). The Peruvian booby Sula variegata was the most abundant seabird with a breeding population of ca. 18,000 pairs concentrated in two islands, followed by the Humboldt penguin Spheniscus humboldti with ca. 9,000 pairs, the largest colony being at Chañaral Island with ca. 7,000 pairs. Kelp gulls Larus domini...

  2. The crustal structure of south central Mongolia using receiver functions

    Science.gov (United States)

    He, Jing; Wu, Qingju; Sandvol, Eric; Ni, James; Gallegos, Andrea; Gao, Mengtan; Ulziibat, Munkhuu; Demberel, Sodnomsambuu

    2016-06-01

    The crustal thickness H and average crustal velocity ratio k (Vp/Vs) beneath south central Mongolia are investigated using the H-k stacking method based on teleseismic radial receiver functions. Our primary results reveal that the local crustal thickness varies from 38 to 46 km with an average value of 43 km. Thicker crust is found beneath the western Hentey Mountains, while thinner crust is located in the southern area of the Zuunbayan fault zone. The Bouguer gravity anomalies exhibit a strong correlation with the overall crustal thickness pattern throughout most of our study regime. Moreover, a new approach which integrates the Bouguer anomaly gradient and the receiver function-derived crustal thickness is adopted to calculate the density of the lower crust underneath central Mongolia. Fairly dense lower crust of approximately 3000 kg/m3 is found in the Middle Gobi Desert. The measured crustal Vp/Vs ratio ranges from 1.68 to 1.83 with an average value of 1.74. Low Vp/Vs ratio is found beneath the western Hentey Mountains. In general, low Vp/Vs ratios correlate well with regions of quartz-rich crust and high heat flow. High Vp/Vs ratios occur in the Middle Gobi volcanic regions and the Mesozoic Southern Gobi Basin.

  3. Ground-water quality in quaternary deposits of the central high plains aquifer, south-central Kansas, 1999

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Water samples from 20 randomly selected domestic water-supply wells completed in the Quaternary deposits of south-central Kansas were collected as part of the High...

  4. Un modelo de la historia de la vegetación de la Cordillera de La Costa de Chile central-sur: la hipótesis glacial de Darwin A model for the history of vegetation of the Coastal Range of central-southern Chile: Darwin's glacial hypothesis

    Directory of Open Access Journals (Sweden)

    CAROLINA VILLAGRÁN

    2001-12-01

    Andean and at high latitudes exist in south-central Chile, between 37 and 43° S. According to Darwin (1859, such "islands" are remnants of glacial populations, which were distributed at lower altitudes and latitudes during glacier advances. Also, in Chile there were expansions of the Andean and southernmost flora into the Longitudinal Valley of Los Lagos region during the last glaciation, which reversed during the Late-glacial (14, 600-10,000 14C years BP and Holocene (after 10,000 14C years BP. Considering this hypothesis, in this study we analyzed two palynological sequences from summits of the Coastal Range of Los Lagos region (Cordillera de Nahuelbuta and Cordillera de Sarao and both were correlated with published high and low altitude records from the Los Lagos and Los Canales regions. The records from the Coastal Range show the following chronological sequence: (1 at the lower and middle Holocene, after 9,040 14C years BP, the Cordillera de Sarao site documents the colonization of Magellanic moorlands and north-Patagonian forest elements, followed by north-Patagonian-Valdivian forest elements during the upper Holocene; (2 the Cordillera de Nahuelbuta site shows the development of conifer forest and Magellanic moorlands during the middle Holocene, ca. 5,430 14C years BP. Other palynological records from the Coastal Range (Cordillera Pelada and Cordillera de Piuchué show the development of both communities during the Late-glacial and lower Holocene. In contrast, the low altitude pollen records from the Los Lagos region indicate that conifers and magellanic moorland elements occupied the Longitudinal Valley during the Last Glacial Maximum (LGM, ca. 22,000 14C years BP. Various pollen profiles from Los Lagos and Los Canales regions evidenced for the late-glacial (14,600-10,000 14C years BP the rapid southern expansion of conifers and other north-Patagonian elements, following the deglaciation of these areas. During the Holocene, Valdivian forest elements invaded the

  5. Challenges Facing Managers in Managing Conflict in Schools in the South and South Central Regions of Botswana

    Science.gov (United States)

    Morake, Nnior Machomi; Monobe, Ratau John; Dingwe, Stephonia

    2011-01-01

    The purpose of this study was to examine the challenges facing managers in managing conflict in schools of South and South Central Regions of Botswana. In this study, the schedule of interview was used to collect empirical data. A random sample of 50 school managers and deputy school managers was selected for interviews. Major findings of the…

  6. Vertebrados terrestres de la Reserva Nacional Río Clarillo, Chile central: representatividad y conservación Terrestrial vertebrates of the Río Clarillo National Reserve, central Chile: representation and conservation

    Directory of Open Access Journals (Sweden)

    IVÁN A. DÍAZ

    2002-06-01

    Full Text Available Analizamos la representatividad, distribución y perspectivas de conservación de los vertebrados terrestres de la Reserva Nacional Río Clarillo, Chile central. Mediante recorridos periódicos realizados entre 1987 y 1996, determinamos la riqueza y distribución altitudinal de los vertebrados terrestres en esta Reserva. Registramos 127 especies (22 mamíferos, 85 aves, 15 reptiles y cinco anfibios, que representan el 69 % del total de especies que por su distribución geográfica y tipo de hábitat podrían habitar este lugar. De éstas, 32 especies (25 % están catalogadas con problemas de conservación. La riqueza de vertebrados decrece con la altitud, desde 101 especies a los 870 m hasta ocho especies a los 3.050 m. La riqueza de vertebrados se concentró bajo los 1.600 m, albergando 109 especies, 55 de las cuales no se registraron a mayor altitud. En cambio, sobre los 1.600 m se registraron 57 especies. Paradójicamente sólo el 31 % de la superficie de la Reserva está bajo los 1.600 m. Nuestros resultados sugieren que la superficie de la Reserva no es suficiente para albergar poblaciones viables de la mayoría de los vertebrados registrados. Alrededor de la Reserva existen propiedades privadas con grandes extensiones de bosques esclerófilos bajo los 1.600 m, los cuales podrían actuar como fuentes y la Reserva como sumidero de vertebrados. Por lo tanto, sugerimos desarrollar estrategias de conservación en estas áreas y realizar monitoreos para determinar si las poblaciones de vertebrados mas sensibles están aumentando o disminuyendo, tanto dentro como fuera de la ReservaWe analyzed the representation, distribution and conservation perspectives of terrestrial vertebrates in the Río Clarillo National Reserve, central Chile. During periodical surveys conducted between 1987 and 1996, we determined the composition and altitudinal distribution of the terrestrial vertebrates in this Reserve. We recorded 127 species (22 mammals, 85 birds, 15

  7. Supervivencia adulta y dinámica poblacional del lauchón orejudo Phyllotis darwini en Chile central Adult survival and population dynamics in the leaf-eared mouse Phyllotis darwini in central Chile

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    Laurent Crespin

    2006-09-01

    Full Text Available A nivel demográfico, los resultados clásicos de los modelos matriciales separan a las especies de tiempo generacional corto de las especies de tiempo generacional largo en cuanto a la importancia de la supervivencia adulta para la dinámica poblacional. Específicamente, la supervivencia adulta no debería contribuir de manera importante en la tasa de cambio poblacional de especies de tiempo generacional corto. Sin embargo, Yoccoz et al. (1998, Research Population Ecology 40: 107-121 propusieron que la supervivencia adulta sería el parámetro demográfico más importante para determinar la tasa de cambio poblacional en pequeños roedores cuando se toma en consideración una escala de tiempo mensual. Con el fin de poner a prueba esta hipótesis en este trabajo, utilizamos cinco años de datos de captura-marcaje-recaptura para estimar la supervivencia y la maduración de las hembras del lauchón orejudo, Phyllotis darwini, en una localidad de Chile central. El análisis mostró que las probabilidades de supervivencia disminuían con el promedio anual de la cantidad de lluvia y que las probabilidades de maduración disminuían con la densidad poblacional. Basados en las probabilidades de supervivencia y maduración, construimos un modelo matricial estacional para medir la importancia relativa de cada parámetro demográfico en el ciclo de vida de la especie a través de un análisis de perturbación. A fin de reflejar la variabilidad estacional del ambiente, dos estaciones fueron incorporadas en el modelo matricial: una estación de lluvia de cinco meses y una estación seca. Se observó que la supervivencia adulta era en efecto el parámetro demográfico con la elasticidad más fuerte. Por lo tanto, estos resultados apoyan la hipótesis de Yoccoz et al. (1998Classic results of matrix models predict that, in species with a long generation time, adult survival should be the demographic parameter driving population dynamics whereas, in species

  8. Hábitos tróficos de la reineta Brama australis (Pisces: Bramidae) durante el periodo estival frente a Chile central

    OpenAIRE

    Francisco Santa Cruz; Ciro Oyarzún; Gustavo Aedo; Patricio Gálvez

    2014-01-01

    La reineta Brama australis es un importante recurso pesquero artesanal en la zona central chilena, incorporado en los programas de seguimiento biológico, pero con escasas evaluaciones de sus aspectos tróficos. Para actualizar el estado del conocimiento, se analizó su dieta durante el verano austral época de mayor disponibilidad de este recurso en la zona central de Chile, mediante el análisis del contenido gástrico de 300 ejemplares capturados entre noviembre 2011 y marzo 2012. Se identificó ...

  9. A Regional GIS of the Central Andes, South America - Integration of Satellite and Geophysical Data Sets

    OpenAIRE

    Hofmann, K; F. K. List;  

    1996-01-01

    The Central Andes of northern Chile, southwestern Bolivia and northwestern Argentina are studied by a research project supported by the Deutsche Forschungsgemeinschaft (SFB 267). The main topics of these geological and geophysical investigations are the orogeny of the Andean mountains and the crustal development at an active continental margin. The "Andean GIS" is designed as a tool for data collection, management, overview, analysis and mapping. The integration of different data supports the...

  10. Corrales de piedra-pirkas- un patrimonio cultural del paisaje rural de Chile central

    OpenAIRE

    Tomic Jakas, Tonci Stipe

    2016-01-01

    Quisiéramos partir con este soliloquio, quizás el más famoso del drama español; ocurre al final del primer acto, cuando Segismundo piensa en la vida y en su suerte. No es el fatalismo lo que interesa si no que desde el inicio explicitar que se trata de una reflexión que lleva a configurar un visión –algo que anida en la mente-- que su fin central radica es tratar de poner en valor sobre la base de la importancia histórica, cultural y patrimonial de los muros de piedra o pirkas; en particular ...

  11. Macroprudential stress-testing practices of central banks in central and south eastern Europe : an overview and challenges ahead

    OpenAIRE

    Melecky, Martin; Podpiera, Anca Maria

    2010-01-01

    Stress tests are the main practical tools of macroprudential oversight. This paper reviews the stress-testing practices of central banks in Central and South Eastern Europe (CSEECBs) and outlines the challenges in the area of stress testing going forward. The authors discuss good practice and the applied approaches by CSEECBs focusing on the main components of a typical macroprudential str...

  12. Volatile Compounds in Honey Produced in the Central Valley of Ñuble Province, Chile Compuestos Volatiles en Miel Producida en el Valle Central de la Provincia de Ñuble, Chile

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    María Pía Gianelli Barra

    2010-03-01

    Full Text Available Headspace solid-phase microextraction (SPME with an 85 µm Carboxen polydimethylsiloxane (CAR/PDMS fiber was used to extract volatile compounds, and a gas chromatograph equipped with a mass spectometry detector (GC-MS was used to identify the volatile compounds in honeys. Thirty-four different volatile compounds from the headspace of honey produced in the central valley of Ñuble Province, Chile, were extracted with fiber coating CAR/PDMS. The identified compounds were: 10 alcohols, 9 acids, 6 ketones, 3 aldehydes, 2 furans, 2 terpenes and 2 lactones. Only four of the volatile compounds had never been reported before as honey compounds; these being: 1,3-propanodiol, 2-methyl butanoic acid, 3,4-dimethyl-3-hexen-2-one, and 6-methyl-5-octen-2-one. These four compounds were found in three of the 10 analyzed samples. The compounds found in the highest percentage of area were ethanol, acetic acid, 1-hydroxy-2-propane, 3-hydroxy-2-butane, and furfural. However, the analyzed samples did not present a distinctive profile.La extracción de compuestos volátiles desde el espacio de cabeza de mieles se realiza mediante microextracción en fase sólida (SPME, utilizando una fibra de 85 µm de Carboxen polidimetilsiloxano (CAR/PDMS, el análisis de los compuestos volátiles se realiza mediante cromatografía de gases con detector de masa (GC-MS. Un total de 34 diferentes compuestos volátiles fueron extraídos desde el espacio de cabeza de mieles provenientes del valle central de la provincia de Ñuble con la fibra de CAR/PDMS. Los compuestos identificados fueron 10 alcoholes, 9 ácidos, 6 cetonas, 3 aldehídos, 2 furanos, 2 terpenos y 2 lactonas. De los compuestos volátiles sólo tres no han sido reportados con anterioridad en mieles, estos compuestos fueron: 1,3-propanodiol, ácido 2-metil butanoico, 3,4-dimetil-3-hexen-2-ona, 6-metil-5-octen-2-ona. Estos cuatro compuestos se encontraron en sólo tres de las 10 muestras analizadas. Los compuestos que se

  13. On the effect of operation of the hydropower plant on the water quality of Rapel reservoir, central Chile

    Science.gov (United States)

    Rossel, V.; De La Fuente, A.

    2013-12-01

    Eutrophication of lakes and reservoirs is a common problem in systems with high incoming loads of nutrients. The consequent algae bloom related to the eutrophication alters the water quality and generates an incompatibility with the tourist and recreational activities. This study is focused on Rapel reservoir: an old, dentritic and monomictic reservoir, located in central Chile (34°S, 71.6°W), that has experienced numerous algae bloom events in the past years produced by high loads of nutrients, sediments and metals. This reservoir was originally constructed in 1968 for hydropower generation without environmental restrictions on its operation. Rapel is part of Chile's Central Interconnected System (SIC), and is controlled by an independent system operator (ISO) that decides the optimal allocation of water by minimizing the SIC's operation cost. As a result of this framework, Rapel reservoir operates based on a hydropeaking scheme, thus producing energy few hours a day while zero outflows are observed the remaining hours, impacting on Rapel river located downstream the reservoir. However, previous research showed that this hydropeaking has important effects on the hydrodynamic of the reservoir as well. Particularly, it enhances vertical mixing nears the dam, and reduces horizontal dispersion. Furthermore, hydropeaking defines the outflows water temperature, and the temperature profile near the dam. As a consequence of this role of hydropeaking on the hydrodynamics and mixing of Rapel reservoir, it is expected to be a link between hydropeaking and water quality. The aim of the study is to evaluate the impact of the operation of hydropower plant on the water quality of Rapel reservoir, for which the reservoir system is modeled using the three dimensional hydrodynamic and water quality model ELCOM-CAEDYM. Field data to validate the results and to define boundary and initial conditions are available for the austral summer period of 2009-2010. Different scenarios of

  14. A time series of prokaryote secondary production in the oxygen minimum zone of the Humboldt current system, off central Chile

    Science.gov (United States)

    Levipan, H. A.; Quiñones, R. A.; Urrutia, H.

    2007-11-01

    Because the marine picoplanktonic communities are made up of phylogenetically different microbial groups, the re-evaluation of key processes such as bacterial secondary production (BSP) has become an important contemporary issue. The difficulty of differentiating the metabolic processes of Bacteria from the rest of the microorganisms in the water column (i.e., Archaea and Eukarya) has made it difficult to estimate in situ BSP. This work presents the seasonal variability of the prokaryote secondary production (PSP) measured by the incorporation of 14C-leucine in the oxygen minimum zone (OMZ) off central-southern Chile. The BSP and potential archaeal secondary production (PASP) were determined through the combined use of 14C-leucine and N1-guanyl-1, 7-diaminoheptane (GC 7), an efficient inhibitor of archaeal and eukaryote cell growth. BSP accounted for the majority of the PSP (total average, 59 ± 7.5%); maximum values were ∼600 μg C m -3 h -1 and, on several dates, BSP represented 100% of the PSP. Similarly, PASP was also an important fraction of the PSP (total average, 42.4 ± 8.5%), although with levels that ranged from not detectable (on given dates) to levels that represented up to ∼97% of PSP (winter 2003). Our results showed that both Bacteria and Archaea accounted for almost equal portions of the prokaryote heterotrophic metabolism in the OMZ, and that PASP is notoriously enhanced through temporal pulses of heterotrophy. This indicates that, at least in marine systems with high abundance of Archaea (e.g., mesopelagic realm), the secondary production obtained through methods measuring the uptake of radiolabeled substrates should be considered as PSP and not as BSP. If the latter is the target measurement, then the use of an inhibitor of both archaeal and eukaryote cell growth such as GC 7 is recommended.

  15. Degradation capability of the coastal environment adjacent to the Itata River in central Chile (36.5° S

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    P. Ampuero

    2011-08-01

    Full Text Available The response of the coastal ocean influenced by both river discharges and inputs of photosynthetically derived organic carbon product of upwelling, was evaluated by estimating rates of microbial hydrolysis of macromolecules with the goal of estimating the potential degradation capability of the coastal ecosystem off central Chile. Extracellular enzymatic activity (EEA in seawater was dominated by aminopeptidase activity on substrate L-leucine-4-methyl-7-coumarinylamide (MCA-leu (1.2 to 182 nmol l−1 h−1 followed by 4-methylumbelliferyl-ß-D-glucoside (MUF-glu (0.08–61 nmol l−1 h−1 and 4-methylumbelliferyl-ß-D-cellobiose (MUF-cel (0.15–7 nmol l−1 h−1, with the highest rates measured during spring-summer. In riverine waters, extracellular enzymatic hydrolysis remained within the range of 45 to 131 nmol l−1 h−1 for MCA-leu and ca. 20 nmol l−1 h−1 for glucosidic substrates, year-round. Contrary to the EEA observed for the marine water column, surface sediment extracellular enzymatic hydrolysis of MCA-leu (0.04 to 6.13 nmol g−1 dw h−1 was in the same order of magnitude as the rates observed for MUF-cel (0.004 to 5.1 nmol g−1 dw h−1 and MUF-glu (0.007 to 10.5 nmol g−1 dw h−1. Moreover, hydrolysis in sediments was characterized by higher rates during winter compared with spring-summer in the coastal and estuarine zone. The five years of data allowed us to evaluate the potential capability of microbial processing of organic carbon in the coastal area adjacent to the Itata river discharge where the increase in primary production in the productive seasons is accompanied by the increase in hydrolysis of macromolecules.

  16. Contribution of legumes to the availability of soil nitrogen and its uptake by wheat in Mediterranean environments of central Chile

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    Soledad Espinoza

    2015-03-01

    Full Text Available The absorption and partitioning of N is determined by its availability and demand during the various phenological stages of the crop. In two experiments conducted in rainfed areas of the Mediterranean climate region of central Chile, legume-wheat (Triticum aestivum L. rotations were compared to oat (Avena sativa L.-wheat systems (with and without applications of N fertilizer. The objective was to assess the contribution of legumes to the availability of soil N and N uptake by the wheat crop following grain legumes. N mineralization and uptake, N use efficiency (NUE, and N uptake efficiency (NUpE by wheat were evaluated at different phenological stages in 2010. Synchronization existed between accumulated soil N mineralization and N uptake by the wheat. N uptake by wheat was higher in Experiment II (Andean foothill than in Experiment I (interior dryland. Grain yields after legumes ranged 60-110% and 72-103% of yields in the fertilized cereal rotation (oat-wheat in Experiments I and II, respectively. There was high correlation between soil N availability vs. grain yield (R² = 0.84 and 0.64 and N uptake vs. grain yield (R² = 0.55 and 0.64 for Experiments I and II, respectively. Rotations with lupine (Lupinus spp. and field peas (Pisum sativum L. showed high NUE and NUpE in Experiment I, and Experiment II in pea. The lowest NUE was after oats with N fertilizers. It is concluded that wheat cultivated in both agro-ecological areas after grain legumes or green manure was more efficient in N uptake and use than cereal, especially when the latter was fertilized.

  17. Prospección serológica del virus parainfluenza 3 en camélidos sudamericanos en Chile A serological survey of parainfluenza-3 virus in South American camelids from Chile

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    CP Cepeda

    2011-01-01

    Full Text Available En un total de 370 sueros obtenidos de 87 alpacas (Lama pacos, 88 llamas (Llama glama, 89 guanacos (Lama guanicoe y 106 vicuñas (Vicugna vicugna se investigó la presencia de anticuerpos para el virus parainfluenza 3 (VPI-3. La prueba de inhibición de la hemoaglutinación mostró que 91 (24,6% de los camélidos sudamericanos (CSA distribuidos en 18 (20,7% alpacas, 36 (40,9% llamas, 27 (18,9% vicuñas y 10 (11,2% guanacos tenían anticuerpos. El rango de los títulos de las muestras positivas estuvo entre 8 y 256 con una media geométrica de 31. Los resultados establecen que los CSA en Chile están infectados con VPI-3.A total of 370 sera collected from 87 alpacas (Lama pacos, 88 llamas (Lama glama, 89 guanacos (Lama guanicoe and 106 vicunas (Vicugna vicugna were investigated for the presence of antibodies to parainfluenza 3 virus (PIV-3. Hemagglutination inhibition test indicated that a total of 91 (24.6% South American camelids (SAC had PIV-3 antibodies, including 18 (20.7% alpacas, 36 (40.9% llamas, 27 (18.9% vicunas and 10 (11.2% guanacos. Titers of the positive samples ranged from 8 to 256 with a geometric mean of 31. These results establish that SAC in Chile are infected with PIV-3.

  18. ESTRUCTURA DE LA MACROFAUNA EN AMBIENTES OXICOS DE BAHIA COLIUMO, REGION DEL BIO-BIO, CHILE CENTRAL STRUCTURE OF MACROFAUNA IN OXIC ENVIRONMENTAL OFF BAY COLIUMO, BIO-BIO REGION, CENTRAL CHILE

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    Karina Neira

    2007-01-01

    Full Text Available Se analizó la densidad, biomasa, diversidad y riqueza de especies de la macrofauna bentónica (³500 mm en ambientes óxicos (> 0.5 ml L-1 en Bahía Coliumo (36º32`S, 72º57`W, Chile central. En un transecto de cinco estaciones, entre 3,6 y 22,5 m de profundidad, fueron recolectadas muestras de sedimento con una draga tipo Van veen de 0,051 m², a bordo de la embarcación científica L/C Kay-Kay. A partir de las muestras de sedimento se determinó, el porcentaje de materia orgánica total, el tamaño de grano, densidad y biomasa de la macrofauna. Adicionalmente, se tomaron muestras de agua para el análisis de oxígeno disuelto de fondo, temperatura y salinidad. Las densidades de la macrofauna total fluctuaron entre 1111 y 11183 ind m-2. En tanto, los valores de biomasa alcanzaron 9,9 y 252,86 g m-2. Del total de la macrofauna 29 especies fueron identificadas. Los valores más altos de diversidad (3,23 coinciden con los valores más bajos de dominancia y uniformidad. Los parámetros de diversidad no mostraron una relación lineal con la profundidad. Los poliquetos fueron el grupo dominante (51,8%, seguido de los crustáceos (41% y moluscos (6,8%. Adicionalmente, a través del análisis BIOENV, se observó que el porcentaje de arena y el contenido de materia orgánica fueron los principales factores ambientales que regulan la estructura de la macrofauna de Bahía Coliumo.The density, biomass, diversity and species richness of macrofaunal benthic (³500 mm in oxic environment (> 0.5 ml L-1 off Bay Coliumo (36º32`S, 72º57`W, Chile were analyzed. One transect of five stations between 3.6 and 22.5 m of depth were collected samples of sediments with a dredged Van veen of 0.051 m²a board R/V Kay-Kay in August (winter of 2004. From sediment sample the organic matter percent, size of grain, density and biomass of the macrofauna were determined. Additionally, were taken water column samples for analyses of dissolved oxygen of bottom, temperature and

  19. Evolución tectónica, paleogeográfica y metalogénica durante el Cenozoico en los Andes de Chile norte y central e implicaciones para las regiones adyacentes de Bolivia y Argentina Tectonic, paleogeographic, and metallogenic evolution during the Cenozoic in the Andes of Central and Northern Chile and implication for the adjacent regions of Bolivia and Argentina

    Directory of Open Access Journals (Sweden)

    Reynaldo Charrier

    2009-10-01

    southern Peru to central Chile and formed the boundary between two paleogeographical domains with dissimilar geological evolutions during the rest of the Cenozoic. The western domain was characterized by erosion and sedimentation processes. The eastern domain also included significant erosional episodes, but was characterized by different evolutions north and south of ~27°S. Northward of this latitude, within the Altiplano-Puna realm, the magmatic arc remained in a fixed position, coinciding with the current active arc, and was bordered by a back-arc foreland basin; whereas southward of ~27°S a succession of magmatic arcs developed with a prominent eastward migration. The Late Eocene to Late Oligocene- Early Miocene was characterized by the development of an extensive intra-arc extensional basin, the Abanico Basin. A succession of volcanic and volcaniclastic rocks, with minor sedimentary intercalations, up to 3,000 m thick were deposited within this basin. At about the boundary between the Oligocene and the Miocene a compressive tectonism affected the whole orogen rejuvenating the core of the Incaic Cordillera and resulted in the tectonic inversion of the Abanico Basin; leading to the syntectonic sedimentation on both sides of the new elevated terrain. The beginning of this tectonism is coincident with the Pehuenche orogeny, but the compression extended until the Early Pliocene. During the Early to Middle Miocene the deformation extended to the east with the development of foreland fold and thrust belts and basins. Within the western domain in northern Chile, area of the current Central Depression and Precordillera, the accumulation of thick sedimentary deposits from the western slope of the Incaic Cordillera originated the Tarapacá and Atacama pediments; whereas an extensive peneplanation developed in central Chile. In Late Miocene the prolonged development of the east-verging fold and thrust belts and the generation of overthrusts deep under the Cordillera, which

  20. Characterization of the hydrothermal system of the Tinguiririca Volcanic Complex, Central Chile, using structural geology and passive seismic tomography

    Science.gov (United States)

    Pavez, C.; Tapia, F.; Comte, D.; Gutiérrez, F.; Lira, E.; Charrier, R.; Benavente, O.

    2016-01-01

    A structural characterization of the hydrothermal-volcanic field associated with the Tinguiririca Volcanic Complex had been performed by combining passive seismic tomography and structural geology. This complex corresponds to a 20 km long succession of N25°E oriented of eruptive centers, currently showing several thermal manifestations distributed throughout the area. The structural behavior of this zone is controlled by the El Fierro-El Diablo fault system, corresponding to a high angle reverse faults of Oligocene-Miocene age. In this area, a temporary seismic network with 16 short-period stations was setup from January to April of 2010, in the context of the MSc thesis of Lira (2010), covering an area of 200 km2 that corresponds with the hydrothermal field of Tinguiririca Volcanic Complex (TVC), Central Chile, Southern Central Andes. Using P- and S- wave arrival times, a 3D seismic velocity tomography was performed. The preliminary locations of 2270 earthquakes have first been determined using an a priori 1D velocity model. Afterwards, a joint inversion of both, the 3D velocity model and final locations have been obtained. High Vp/Vs ratios are interpreted as zones with high hot fluid content and high fracturing. Meanwhile, low Vp/Vs anomalies could represent the magmatic reservoir and the conduit network associated to the fluid mobility. Based on structural information and thermal manifestations, these anomalies have been interpreted. In order to visualize the relation between local geology and the velocity model, the volume associated with the magma reservoir and the fluid circulation network has been delimited using an iso-value contour of Vp/Vs equal to 1.70. The most prominent observed feature in the obtained model is a large "V" shaped low-velocity anomaly extending along the entire study region and having the same vergency and orientation as the existing high-angle inverse faults, which corroborates that El Fierro-El Diablo fault system represents the

  1. Caracterización y procedencia de obsidianas de sitios arqueológicos del Centro Oeste de Argentina y Centro de Chile con metodología no destructiva por fluorescencia de Rayos X (XRF Non-destructive x-ray fluorescence (XRF characterization and sourcing of obsidian from archaeological sites in Central West Argentina and Central Chile

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    Víctor Durán

    2012-11-01

    Full Text Available Se presentan los resultados de 101 análisis químicos por fluorescencia de Rayos X efectuados sobre artefactos de obsidiana provenientes de sitios arqueológicos del Centro Oeste Argentino y Chile Central. También se hace una caracterización química de seis fuentes y subfuentes de obsidiana ubicadas en ambientes cordilleranos y extracordilleranos del sur de Mendoza, Neuquén y Chile Central. Con esa información se discuten propuestas referidas a la movilidad y sistemas de intercambio de las sociedades humanas que ocuparon las dos vertientes de la cordillera de Los Andes durante el Holoceno medio y tardío. Los resultados obtenidos confirman que el método no destructivo por XRF es una herramienta válida para determinar el origen y dispersión de las obsidianas arqueológicas.The results of chemical analysis by X-ray Fluorescence (XRF performed on 101 obsidian artifacts from archaeological sites of Central western Argentina and Central Chile are presented. A chemical characterization of six obsidian sources and subsources located in both Andean and extra-Andean environments of Southern Mendoza, Northern Neuquén and Central Chile, is also performed. Based on this information, different proposals related to mobility patterns and exchange systems of human societies that occupied the two slopes of the Andes during the middle and late Holocene are discussed. The results confirm that non-destructive X-ray Fluorescence is a valid tool to determine the origin and dispersal of archaeological obsidian artifacts.

  2. Receiver Function Migration of Broadband Seismograms recorded by the International Maule Aftershock Deployment (IMAD) in Central Chile

    Science.gov (United States)

    Morell, M.; Beck, S. L.; Roecker, S. W.; Meltzer, A.; Russo, R. M.

    2011-12-01

    The Mw=8.8 Maule earthquake that occurred off the coast of Chile on February 27, 2010 is one of the largest megathrust earthquakes ever to be recorded and ruptured ~600 km of the plate boundary. This segment of the Nazca-South America plate boundary is an ideal region to investigate the processes related to the structure of the down-dip edge of the seismogenic zone, forearc wedge and subducting slab. Immediately after the Maule earthquake, international teams from France, Germany, Great Britain and the United States joined Chilean seismologists to install an array of seismic stations between 33°-38.5°S, from the coast to the foothills of the Andes to produce the International Maule Aftershock Deployment (IMAD) data set. These arrays were deployed from mid-March until the end of December 2010 in order to capture and study the aftershocks in and around the rupture zone, and to better understand crustal and mantle wedge structure. We calculated receiver functions (RFs) from P and PP phases and made Common Conversion Point stacks to image the structures in the slab and forearc wedge down to a depth of 100 km. We have identified the oceanic slab Moho on several E-W and N-S profiles at 40 to 60 km depth beneath the array and several discontinuities above the slab in the forearc. These profiles also show a large low-velocity zone beneath the northern half of the array in the forearc. In addition, we are using a 2.5D finite difference teleseismic waveform tomography technique described in Roecker et al. (2010) to image the crust and upper mantle beneath that part of the Chilean Andes occupied by the IMAD array and the earlier TIPTEQ deployment of Rietbrock et al. (2005). While the technique does not require any kind of formal source deconvolution, in sparse deployments we can apply this technique in an RF type migration by normalizing medium sensitivities. Both these techniques will improve our imaging of the down-dip limit of the seismogenic zone, forearc wedge and

  3. Personajes fuera de lugar: antropomorfos tardíos en el arte rupestre del norte semiárido de Chile Images out of place: late period antropomorphous figures in the rock art of central Chile

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    Andrés Troncoso

    2011-07-01

    , in the Choapa Province, north-central Chile (30°LS. We will discuss the chronology, affinities and relations between these anthropomorphous figures and their northern counterparts and evaluate why they are present in places so far away from their original spatial distribution pattern. Also we discuss the relations between these designs and the image circulation realized by the Tawantinsuyu.

  4. Water input and water release from the subducting Nazca Plate along southern Central Chile (33°S-46°S)

    Science.gov (United States)

    Völker, David; Stipp, Michael

    2015-06-01

    The age of the subducting Nazca Plate off Chile increases northward from 0 Ma at the Chile Triple Junction (46°S) to 37 Ma at the latitude of Valparaíso (32°S). Age-related variations in the thermal state of the subducting plate impact on (a) the water influx to the subduction zone, as well as on (b) the volumes of water that are released under the continental fore arc or, alternatively, carried beyond the arc. Southern Central Chile is an ideal setting to study this effect, because other factors for the subduction zone water budget appear constant. We determine the water influx by calculating the crustal water uptake and by modeling the upper mantle serpentinization at the outer rise of the Chile Trench. The water release under fore arc and arc is determined by coupling FEM thermal models of the subducting plate with stability fields of water-releasing mineral reactions for upper and lower crust and hydrated mantle. Results show that both the influx of water stored in, and the outflux of water released from upper crust, lower crust, and mantle vary drastically over segment boundaries. In particular, the oldest and coldest segments carry roughly twice as much water into the subduction zone as the youngest and hottest segments, but their release flux to the fore arc is only about one fourth of the latter. This high variability over a subduction zone of <1500 km length shows that it is insufficient to consider subduction zones as uniform entities in global estimates of subduction zone fluxes.

  5. Mid-cretaceous crustal shortening: evidence from a regional-scale ductile shear zone in the Coastal Range of central Chile (32° S)

    Science.gov (United States)

    Arancibia, Gloria

    2004-11-01

    In the Coastal Range of central Chile, widespread Early Cretaceous volcanism associated with extensional volcanosedimetary intra- or back-arc basins and subsequent basin closures, uplift, and increased erosion/exhumation rates during the mid-Cretaceous suggests a major change from a mainly extensional tectonic regime to a relatively contractional regime and resultant crustal shortening. The author documents the contractional Silla del Gobernador shear zone (SGSZ), which developed at the western boundary of the Coastal Range in central Chile (32° S). This structure corresponds to a high-strain ductile and cataclastic shear zone that developed under low-grade (greenschist facies) metamorphic and fluid-present conditions, which indicates EW-NWW crustal shortening in a compressional (transpressional) regime. UVLAMP 40Ar/ 39Ar laserprobe dating of neoformed white mica during mylonitic deformation suggests a maximum age for the reverse ductile shearing of 109±11 Ma. An inverse isochron age of 97.8±1.5 Ma from biotite samples of a mylonitized granodiorite suggests the minimum age of deformation. These ages constrain the ductile deformation age to approximately 100 Ma (mid-Cretaceous), coeval with high exhumation/erosion rates that appear to represent uplift of the Coastal Range. The uplift and crustal shortening of the Coastal Range of central Chile has been associated with high spreading rates from the SE Pacific and southern Atlantic convergence during a change from an extensional regime developed during the Early Cretaceous to a more compressional regime that started during the mid-Cretaceous. In this sense, the SGSZ records this tectonic regime change.

  6. Modelación y análisis probabilístico del balance hídrico superficial de un sistema de riego en Chile Central

    OpenAIRE

    Molina, José Manuel; Gurovich R., Luis A.; Varas, Eduardo

    2003-01-01

    El presente artículo presenta una propuesta de modelación de los elementos y procesos involucrados en la oferta superficial y demanda hídrica de un sistema de riego de la zona central de Chile, como metodología para el estudio del balance hídrico predial en la planificación de los recursos hídricos disponibles. El estudio contempló una descripción y evaluación general del sistema mediante visitas de terreno y recolección de información, teniendo en cuenta aspectos de suelos, cultivos, agua...

  7. Consideraciones biogeográficas y ecológicas de equinodermos arquibentónicos de Chile Central (com excepción de crinoidea

    Directory of Open Access Journals (Sweden)

    Héctor Andrade Vasquez

    1980-12-01

    Full Text Available 30 echinoderm species (the crinoias excepted have been recorded from the archibenthos off Central Chile. Samples were taken at 5 stations (from Los Vilos to Quíntero. 250-450 m depth range, every 15 days for one year. The concept of Region or Province, usually related to the intertital fauna from high latitudes are showed to be impractical using them with archibenthal echinoderms. The presence oj some species that had been registered as characteristic from the Antarctic Region and/or present in the Argentinian and Magellanic Province is related with the Antarctic Intermediate Water Mass, which is at the capture depth in the sampled area.

  8. The Jurassic-Cretaceous Boundary (Tithonian - Hauterivian) in the Andean Basin of Central Chile: Ammonites, Bio- and Sequence Stratigraphy and Palaeobiogeography

    OpenAIRE

    Salazar Soto, Christian Andrés

    2012-01-01

    Five sections of the Baños del Flaco and Lo Valdés formations in the High Andean Cordillera of Central Chile have been analyzed with regard to sediment, bio- and sequence stratigraphy, ammonite assemblages and palaeobiogeography, in order to reveal the age and depositional facies of the sediment sequence, and to evaluate the age and important bioevents across the Jurassic-Cretaceous boundary. The Baños del Flaco Formation was investigated at Rio Tinguiririca and in the Rio Maitenes valley,...

  9. Hábitos tróficos de la reineta Brama australis (Pisces: Bramidae durante el periodo estival frente a Chile central

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    Francisco Santa Cruz

    2014-11-01

    Full Text Available La reineta Brama australis es un importante recurso pesquero artesanal en la zona central chilena, incorporado en los programas de seguimiento biológico, pero con escasas evaluaciones de sus aspectos tróficos. Para actualizar el estado del conocimiento, se analizó su dieta durante el verano austral época de mayor disponibilidad de este recurso en la zona central de Chile, mediante el análisis del contenido gástrico de 300 ejemplares capturados entre noviembre 2011 y marzo 2012. Se identificó una dieta dominada por Euphausia mucronata (IIR = 92,33, aunque a escala mensual se identificó una dieta mixta de E. mucronata durante noviembre, diciembre 2011 y marzo 2012, además de Pterygosquilla armata y anfípodos hipéridos durante enero y marzo 2012. No se encontró diferencias significativas entre ambos sexos (P > 0,01. Estos resultados demuestran y corroboran que B. australis es un depredador pelágico con un reducido espectro trófico en el litoral de Chile central.

  10. Using fecal profiles of bile acids to assess habitat use by threatened carnivores in the Maulino forest of central Chile Empleo del perfil de ácidos biliares fecales para evaluar uso del hábitat por carnívoros amenazados en el bosque maulino de Chile central

    OpenAIRE

    CARLA GUERRERO; LUIS ESPINOZA; HERMANN M. NIEMEYER; JAVIER A SIMONETTI

    2006-01-01

    The distribution and habitat use by carnivores can be assessed by studying their tracks or feces. If these methods are to be used confidently, they should not only unequivocally discriminate among species, but should also render the same patterns of spatial distributions. We assessed the fulfillment of these requirements with five carnivores inhabiting the Maulino forest of central Chile: Galictis cuja, Oncifelis guigna, Pseudalopex culpaeus, Pseudalopex griseus, and Puma concolor. Fecal bile...

  11. Biología reproductiva del águila Geranoaetus melanoleucus (Aves: Accipitridae en Chile central Breeding biology of the black-chested eagle Geranoaetus melanoleucus (Aves: Accipitridae in central Chile

    Directory of Open Access Journals (Sweden)

    EDUARDO F. PAVEZ

    2001-09-01

    Full Text Available Durante dos años (julio 1987­enero 1989 se estudió la biología reproductiva del águila (Geranoaetus melanoleucus en San Carlos de Apoquindo, en Chile central. El inicio del período reproductivo se evidenció por un aumento del número de vuelos en pareja. Los cortejos incluyeron vuelos sincronizados de la pareja, capturas, transporte de material al nido y cópulas. Los traspasos de presas ocurrieron durante todo el año, aunque fuera del período reproductivo fueron escasos y forzados por la hembra. Se localizaron 4,7 nidos pareja-1, lo que está en el límite superior documentado para grandes águilas. Fuera del período reproductivo las águilas visitaron ocasionalmente los nidos. Antes de la postura el macho visitó el nido con mayor frecuencia y por menos tiempo que la hembra. En las tres parejas estudiadas se observó visitas a nidos alternativos, con aporte de material y presas. Se promedió 2,3 huevos postura-1 (DE = 0,5, n = 6, incubando macho y hembra, y eclosionando el 100 %. A los 25 días de edad comenzaron a emerger las plumas de vuelo de los pollos, a los 35 días comían solos las presas aportadas al nido y a los 59 días abandonaron el nido. Durante la crianza la hembra permaneció más tiempo en el nido que el macho, con una tendencia de los adultos a disminuir el tiempo de permanencia en el nido. El 79 % de los pollos sobrevivió a la crianza, lo que se puede considerar un éxito reproductivo elevado, y que se explicaría por la elevada disponibilidad de presas en el sitio de estudio, particularmente de conejos. Los pollos permanecieron en el territorio paterno 10 meses, lo que coincidió con la siguiente postura de huevos, disminuyendo gradualmente su presencia en el área y aumentando la intolerancia de los adultos hacia sus hijos. Los resultados presentados se corresponden con el patrón descrito en la literatura para otras águilasThe breeding biology of the black-chested eagle (Geranoaetus melanoleucus was studied

  12. Parasites of the Green-backed Firecrown (Sephanoides sephaniodes in Chile Parásitos del picaflor chico (Sephanoides sephaniodes en Chile

    Directory of Open Access Journals (Sweden)

    Daniel González-Acuña

    2011-12-01

    Full Text Available Gastrointestinal and external parasites from 12 Green-backed Firecrown (Sephanoides sephaniodes were collected between January 2004 and December 2008 from the Biobío Region south-central Chile and Santiago (central Chile. Helminths collected included 1 trematode species (Mosesia sp. and 1 cestode species (Hymenolepis trinidadensis. The mite Proctophyllodes huitzilopchtlii was the only ectoparasite species found. All these parasites represent new records for Chile and the first parasites reported for this host species.Se recolectaron parásitos internos (gastrointestinales y externos de 12 picaflores (Sephanoides sephaniodes entre enero del 2004 y diciembre del 2008, de la región del Biobío en el centro-sur de Chile y en Santiago, en la región central de Chile. Los helmintos recolectados incluyeron 1 especie de trematodo (Mosesia sp. y 1 de cestodo (Hymenolepis trinidadensis. Únicamente se encontró 1 especie de ectoparásito, el ácaro Proctophyllodes huitzilopchtlii. Todos los parásitos mencionados representan nuevos registros para Chile y se registran por primera vez para este hospedero.

  13. Constraining the magma flow record based on magmatic and magnetic data in La Gloria Pluton, central Chile

    Science.gov (United States)

    Gutierrez, F. J.; Payacán, I.; Gelman, S. E.; Bachmann, O.; Creative Physical Petrology Team

    2013-05-01

    The magmatic origin of the anisotropy of magnetic susceptibility (AMS) is examined in comparison with magmatic anisotropy data in a small, shallow, silicic magma reservoir in the upper crust. La Gloria Pluton (LGP) is a 10 Ma granodiorite/quartz monzonite of about 250 km3 located in the southern Andes, central Chile. LGP represents a particularly simple case of a silicic intrusion that was assembled in only a few pulses and cooled over a short time interval. Hornblende, biotite and minor magnetite are ubiquitous mafic phases. The AMS tensor indicates that magnetic fabric has an oblate shape (i.e. magnetic foliation is higher than magnetic lineation). Lineations are weak (values up to 1.05), have a N-NW trend with a nearly horizontal dip and are interpreted to represent axisymmetric convection parallel to the main pluton elongation. Foliations are more pronounced (values up to 1.14), having NW trends and dips that vary gradually from vertical at the walls, to horizontal at the center and near the roof of the chamber. We selected 12 samples from AMS sites to obtain petrographic data (well-distributed throughout the pluton, containing samples from the walls, the center and the roof of LGP), and then, determine the magmatic fabric (anisotropy, lineation, foliation). We made 3 oriented thin sections per sample oriented with the AMS. Magmatic anisotropy data were obtained by measuring mineral length, width and orientation in photomicrographs of the three main planes of the AMS tensor, producing 3-D mineral data which were collected for plagioclase and amphibole + bitotite independently. For each site, a Bingham distribution with 95% of confidence is used to determine the mean mineral orientations and their angle difference with the AMS axes. Magmatic anisotropy tensor and rotations with respect to the AMS tensor are determined using both eigenvalues and minimization algorithms. Preliminary results indicate that crystals are coherently oriented in both mineral groups, and

  14. Chemosynthetic trophic support for the benthic community at an intertidal cold seep site at Mocha Island off central Chile

    Science.gov (United States)

    Sellanes, Javier; Zapata-Hernández, Germán; Pantoja, Silvio; Jessen, Gerdhard L.

    2011-12-01

    We analyzed C and N stable isotope ratios of benthic fauna and their potential food sources at an intertidal methane seep site and a control site without emanation at Mocha Island (central Chile). The objective was to trace the origin of the main food sources used by the local heterotrophic fauna, based on the hypothesis that chemosynthetic production could be partially fueling the local food web at the seep site. Food sources sampled at both sites included macroalgae, particulate organic matter and bacteria-like filaments found growing over the red algae Gelidium lingulatum within the areas of active methane release. At the control site, located 11 km away from the gas emanation, fauna exhibited moderate δ 13C values ranging from -16.2‰ (in a nereid polychaete) to -14.8‰ (in a cirolanid isopod), which were consistent with those of the potential photosynthetic food sources sampled at this site (-20.2 to -16.5‰). δ 13C values of the photosynthetic food sources at the seep site similarly ranged between -25.4 and -17.9‰. However, a portion of the animals at this site were consistently more 13C-depleted, with δ 13C values close to that of the seeping methane (-43.8‰) and the bacteria-like filaments (-39.2 ± 2.5‰) also collected at this site. Specific examples were the Marphysa sp. polychaetes (δ 13C = -44.7 ± 0.6‰), the Schistomeringos sp. dorvilleid polychaetes (δ 13C = -42.9‰), and the tanaid crustacean Zeuxo marmoratus (δ 13C = -37.3 ± 0.2‰). The significantly higher δ 13C values of the herbivorous gastropod Tegula atra at the seep site (-29.3 ± 3.1‰) than at the control site (-12.6 ± 0.3‰) also indicated differences among sites of the preferred carbon sources of this species. Mixing model estimates indicate that at the seep site bacteria-like filaments could be contributing up to ˜60% of the assimilated diet of selected invertebrates. Furthermore, several indicators of trophic structure, based in isotopic niche metrics, indicate a

  15. Combined impact of ocean acidification and corrosive waters in a river-influenced coastal upwelling area off Central Chile

    Science.gov (United States)

    Vargas, C.; De La Hoz, M.; San Martin, V.; Contreras, P.; Navarro, J. M.; Lagos, N. A.; Lardies, M.; Manríquez, P. H.; Torres, R.

    2012-12-01

    Elevated CO2 in the atmosphere promotes a cascade of physical and chemical changes affecting all levels of biological organization, and the evidence from local to global scales has shown that such anthropogenic climate change has triggered significant responses in the Earth's biota. The increased concentration of CO2 is likely to cause a corresponding increase in ocean acidification (OA). In addition, economically valuable shellfish species predominantly inhabit coastal regions both in natural stocks and/or in managed stocks and farming areas. Many coastal ecosystems may experience seawater pCO2 levels significantly higher than expected from equilibrium with the atmosphere, which in this case are strongly linked to biological processes and/or the impact of two important processes; river plumes and coastal upwelling events, which indeed interplay in a very dynamic way on continental shelves, resulting in both source or sink of CO2 to the atmosphere. Coastal ecosystems receive persistent acid inputs as a result of freshwater discharges from river basins into the coastal domain. In this context, since shellfish resources and shellfish aquaculture activities predominantly occur in nearshore areas, it is expected that shellfish species inhabiting river-influenced benthic ecosystems will be exposed persistently to acidic conditions that are suboptimal for its development. In a wider ecological context, little is also known about the potential impacts of acid waters on the performance of larvae and juveniles of almost all the marine species inhabiting this benthic ecosystem in Eastern Southern Pacific Ocean. We present here the main results of a research study aimed to investigate the environmental conditions to which economically valuable calcifiers shellfish species are exposed in a river-influenced continental shelf off Central Chile. By using isotopic measurements in the dissolved inorganic carbon (DIC) pool (d13C-DIC) we showed the effect of the remineralization of

  16. Alstroemeria presliana Herb. (Alstroemeriaceae) in Chile from a Cytogenetic Perspective Alstroemeria presliana Herb. (Alstroemeriaceae) en Chile Bajo una Perspectiva Citogenética

    OpenAIRE

    Carlos M Baeza; Otto Schrader; Eduardo Ruiz; M Negritto

    2008-01-01

    Alstroemeria (Alstroemeriaceae) is an endemic genus of South America with two major distribution centers in the continent: Chile and Brazil. In Chile the genus is distributed from the North, near Iquique (20º13’ S, 70º09’ W) to the Chilean and Argentine Patagonia (53º10’ S, 70º54’ W). The central zone of Chile presents the highest number of species. A. presliana Herb. grows from Curicó (34º59’ S, 71º14’ W) to Cautín (38º45’ S, 72º34’ W) in Chile and Neuquén (36º50’ S, 71º05’ W), Argentina. A ...

  17. POTENTIAL AND LIMITS OF RENEWABLE ENERGY IN THE CENTRAL AND SOUTH-EAST EUROPE REGION

    OpenAIRE

    CIRLEA Filip; Iancu, Iulian

    2012-01-01

    Renewable energy sources (solar power, wind power, hydroenergy, biomass, biofuels) with energy efficiency contribute to increasing security of electricity supply, competitiveness and sustainable development. The countries of the Central and South-East Europe region must to develop a focus on alternative energy sources and on energy efficiency and energy saving. Developing the renewable energy sector in a sustainable manner in the Central and South-East Europe region would enhance security of ...

  18. Future Temperatures and Precipitations in the Arid Northern-Central Chile: A Multi-Model Downscaling Approach

    Science.gov (United States)

    Souvignet, M.; Heinrich, J.

    2010-03-01

    Downscaling of global climate outputs is necessary to transfer projections of potential climate change scenarios to local levels. This is of special interest to dry mountainous areas, which are particularly vulnerable to climate change due to risks of reduced freshwater availability. These areas play a key role for hydrology since they usually receive the highest local precipitation rates stored in form of snow and glaciers. In the central-northern Chile (Norte Chico, 26-33ºS), where agriculture still serves as a backbone of the economy as well as ensures the well being of people, the knowledge of water resources availability is essential. The region is characterised by a semiarid climate with a mean annual precipitation inferior to 100mm. Moreover, the local climate is also highly influenced by the ENSO phenomenon, which accounts for the strong inter-annual variability in precipitation patterns. Although historical and spatially extensive precipitation data in the headwaters of the basins in this region are not readily available, records at coastal stations show worrisome trends. For instance, the average precipitation in La Serena, the most important city located in the Coquimbo Region, has decreased dramatically in the past 100 years. The 30-year monthly average has decreased from 170 mm in the early 20th century to values less than 80 mm nowadays. Climate Change is expected to strengthen this pattern in the region, and therefore strongly influence local hydrological patterns. The objectives of this study are i) to develop climate change scenarios (2046-2099) for the Norte Chico using multi-model predictions in terms of temperatures and precipitations, and ii) to compare the efficiency of two downscaling techniques in arid mountainous regions. In addition, this study aims at iii) providing decision makers with sound analysis of potential impact of Climate Change on streamflow in the region. For the present study, future local climate scenarios were developed

  19. A study of the relationship between degree of ethnocentrism and typologies of food purchase in supermarkets in central-southern Chile.

    Science.gov (United States)

    Schnettler, Berta; Miranda, Horacio; Lobos, Germán; Sepúlveda, José; Denegri, Marianela

    2011-06-01

    The objective of this study was to distinguish different types of consumers according to their level of ethnocentrism in relation to the consumption of foodstuffs in central-southern Chile. To do this a modification of the CETSCALE (Consumer Ethnocentric Tendencies Scale) was applied through direct survey of 800 habitual supermarket shoppers in two cities in central-southern Chile. The modified CETSCALE presented a sufficient level of internal consistency and there were three factors which included the 17 items of the scale. Five typologies of consumer with different degrees of ethnocentrism were distinguished by cluster analysis, based on the values of the factors and items in the CETSCALE. The composition of the typologies of consumers were related to the city and zone of residence, age, socioeconomic level, self-declared life-style, ethnic origin, knowledge of the origin of the foodstuffs purchased, frequency of purchase of imported foodstuffs and reasons for rejection in the case of a low purchase frequency. It may therefore be concluded that different levels of ethnocentrism exist in the consumption of foodstuffs, related with some socio-demographic characteristics of consumers and their attitudes to imported foodstuffs. PMID:21335039

  20. Real time earthquake information and tsunami estimation system for Indonesia, Philippines and Central-South American regions

    Science.gov (United States)

    Pulido Hernandez, N. E.; Inazu, D.; Saito, T.; Senda, J.; Fukuyama, E.; Kumagai, H.

    2015-12-01

    . Acknowledgments Real-time seismic data from Indonesia and Philippines is received at NIED in the framework of cooperative research projects with BMKG (Indonesia), PHIVOLCS (Philippines), and GFZ (Germany). Seismic data from Central and South America is obtained from IRIS as well as the Integrated Plate Boundary Observatory of Chile.

  1. Cambios de largo plazo en el paisaje y los ensambles de micromamíferos y rapaces en Chile central Long-term changes in landscape and in small mammal and raptor assemblages in central Chile

    Directory of Open Access Journals (Sweden)

    EDUARDO F PAVEZ

    2010-03-01

    Full Text Available San Carlos de Apoquindo, en la precordillera de Chile central, es una localidad con estudios de larga data en vertebrados (ca. 30 años, situación favorable para el análisis de procesos de largo plazo que operan sobre dichos ensambles. En este contexto estudiamos la trayectoria del uso del suelo mediante imágenes satelitales LANDSAT, correspondientes a 1975, 1989 y 2003 y su presunto efecto sobre la vegetación, micromamíferos y aves rapaces. El análisis de las imágenes satelitales revela una expansión acelerada del área urbana en desmedro del suelo agrícola y matorrales naturales. Las especies de micromamíferos nativos de talla reducida y media no evidencian grandes variaciones de abundancia durante el período de estudio pero las de mayor tamaño redujeron sus poblaciones. El conejo europeo (Oryctolagus cuniculus es una de las especies más abundantes del área, y estaría siendo favorecido por la modificación del paisaje. En la dieta del águila (Geranoaetus melanoleucus y del peuco (Parabuteo unicinctus se observó una disminución sostenida de la principal presa nativa, el degú (Octodon degus y un aumento de la presa exótica, el conejo. Además se observó una tendencia a la disminución de la riqueza y abundancia de aves rapaces durante el período de estudio, la que se asociaría a la expansión urbana y al deterioro del matorral natural. Postulamos que la expansión urbana y la pérdida y fragmentación del matorral han producido una disminución de la población de degú, con su consecuente disminución en la dieta de águilas y peucos, lo que a su vez ha potenciado un incremento de depredación sobre conejo.San Carlos de Apoquindo, a piedemont area to the east of Santiago city, is a site with 30 years of data on vertebrates. Using LANDSAT satellite imagery for the years 1975, 1989 and 2003, we studied the spatio-temporal trajectory of land use and its putative effects on vegetation, small mammals and raptors. On the basis

  2. Botanical Composition of Alpaca (Lama pacos Linn. Diet in a Central Mediterranean Range of Chile Composición Botánica de la Dieta de Alpaca (Lama pacos Linn. en un Pastizal del Secano Mediterráneo de la Zona Central de Chile

    Directory of Open Access Journals (Sweden)

    G Castellaro

    2008-06-01

    Full Text Available The re-introduction of domestic South American camelids (alpacas and llamas in the central zone of Chile makes it necessary to study their behaviour and adaptability. Since it is fundamental to characterize the camelid’s diet, the present work had as an objective the determination of the plant species selected by the alpacas (Lama pacos Linn. in different phenological stages (vegetative, reproductive and dry season. The study was carried out over three years in a paddock of 2.5 ha of sparse shrubland dominated by Acacia caven (Mol. Mol. and annual species in the herbaceous stratum, which were continually grazed by five male alpacas. The botanical composition and the forage dry matter available for grazing in the pasture was evaluated. Botanical composition of diets was estimated with the microhistological technique, using dung samples collected directly from the rectum. During the vegetative season, the most consumed plant species were annual and perennial grasses. In the reproductive season, the most important components of the diet were woody plant species, annual grasses and forbs. In the dry season, the diet was composed of a high percentage of woody plant species.La reintroducción de camélidos sudamericanos domésticos (alpaca y llamas en la zona central de Chile, hace necesario estudiar su comportamiento y adaptabilidad. En este contexto, la caracterización de la dieta es fundamental. Por ello, el presente trabajo tuvo como objetivo determinar las especies vegetales seleccionadas por las alpacas en diferentes etapas fenológicas del pastizal (vegetativo, reproductivo y seco. El estudio se realizó durante tres temporadas en un potrero de 2,5 ha ocupado por un matorral claro dominado por Acacia caven (Mol. Mol. y especies anuales en el estrato herbáceo, las cuales fueron pastoreadas continuamente por cinco alpacas macho. En la pradera se evaluó la composición botánica y la disponibilidad de la materia seca bajo pastoreo. La

  3. Efectos de la planta en cojín Oreopolus glacialis (Rubiaceae sobre la riqueza y diversidad de especies en una comunidad alto-andina de Chile central Effects of the cushion plant Oreopolus glacialis (Rubiaceae on species richness and diversity in a high-Andean plant community of central Chile

    Directory of Open Access Journals (Sweden)

    ERNESTO I BADANO

    2002-12-01

    we analyzed the effect of Oreopolus glacialis -a cushion plant from the South American Andes- on the species richness, total and individual abundance, diversity and evenness of a plant community located in a high mountain environment at 1,900 m of altitude in central Chile. Species richness and abundance were determined both within and outside O. glacialis cushions. Results showed that, per area, species richness and individual abundance were higher within cushions. In contrast, diversity and evenness within O. glacialis cushions were lower than outside. This apparent incongruence was caused by some species being highly dominant within cushions. Analyses of the frequency and abundance of each species showed that not all the species were affected in the same way by the cushions, with only four species growing more frequently within cushions. This suggests that nurse effect of O. glacialis is a species-specific phenomenon

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

    Directory of Open Access Journals (Sweden)

    Gagandeep Singh

    1997-09-01

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

  5. Recurrent mesoproterozoic continental magmatism in South-Central Norway

    DEFF Research Database (Denmark)

    Pedersen, Svend; Andersen, Tom; Konnerup-Madsen, Jens;

    2009-01-01

    We report U-Pb dates and Lu-Hf isotope data, obtained by LAM-ICPMS, for zircons from metamorphic rocks of the Setesdalen valley, situated in the Telemark block south of the classic Telemark region of southern Norway. The samples include infracrustal rocks from the metamorphic basement, metaigneous...... increased with time. Around 1,320 Ma, further addition of juvenile material occurred, involving both mafic and felsic melts, metamorphism and deformation. Acid magmas with high FeO*/MgO were intruded at 1,215 Ma, coinciding with underplating elsewhere in South Norway. The period starting at 1,215 Ma is...

  6. Habronyx Foerster (Hymenoptera: Ichneumonidae: Anomaloninae) in Andean and Neantarctic South Americawith description of new species from Bolivia and Chile

    OpenAIRE

    Charles C. Porter

    2009-01-01

    Habronyx Foerster occurs in all regions except the Afrotropical and parasitizes lepidopterous larvae (Geometridae, Noctuidae, Saturniidae, Sphingidae, Psychidae). Habronyx albifrons (Spinola) inhabits neantartic Chile and southern Argentina. It is black with a white flagellar annulus and with a strong prepectal carina on the lower half of the mesopleuron. Habronyx albifrons is redescribed and descriptions are given of two new species which belong to a group of their own: Habronyx citrinus Por...

  7. Infrastructure development and agricultural exposure to climate variability and change: lessons from the Limarí basin in Central Chile

    Science.gov (United States)

    Vicuna, S.; Alvarez, P.; Melo, O.; Dale, L. L.; Meza, F. J.

    2012-12-01

    The Limarí basin, located in Central Chile, is a world famous example of how the development of reservoirs and irrigation infrastructure can reduce climate vulnerabilities allowing the economic development of a basin. Before the infrastructure was developed low value crops such as cereals dominated land use acreage. Today high value crops such as vineyards, orchards and vegetables account for almost 50% of total land and cereals have almost disappear. Key to this evolution have been the reduction in water supply variability, access to international markets, increased irrigation efficiency, and the existence of water markets and other flexible and strong institutions that have helped moving the water from low to high value uses. These factors are related to each other sharing infrastructure development as a common root. The system of reservoirs in the Limarí basin was designed and has been operated since its construction with the premise that droughts in this basin do not last longer than 4 years. Until recently that had been the case and farmers have been able to withstand the impacts of droughts. When faced with water supply reductions farmers would select from a set of options to accommodate their needs including: water market participation, groundwater extraction and crop irrigation and crop acreage decisions. The use of these options has even allowed increasing total irrigated land mostly through the expansion of permanent water demand crops. In the past 9 years however, the basin has experienced a longer than usual drought, interrupting the reservoir refilling cycle that characterized climate variability in the region. This situation has led to dramatically low reservoir levels and continuous reductions in water supply. In addition, due to the already high levels of irrigation efficiency and large amount of acreage devoted to permanent water demand crops, the effectiveness of the portfolio of options available to farmers to accommodate to these stressing

  8. Sr-Nd-Pb isotope compositions of felsic intrusions in the El Teniente and Laguna La Huifa areas, Central Chile

    International Nuclear Information System (INIS)

    The giant El Teniente porphyry Cu-Mo deposit is located in the Andes foothills of Central Chile (34oS). In simplistic terms, the igneous rocks at the mine can be grouped in two major units: a felsic suite of silicic intrusives (the porphyries; SiO2≥56wt%) with subvertical stock-like to dyke shapes, and a mafic volcanic to subvolcanic sequence (the Farellones formation; SiO2<≤56wt%) with a sub-horizontal nature. The felsic rocks intrude the volcanogenic Farellones formation, which is known at the mine site as 'Andesitas de la mina'. The major felsic intrusives are locally known as the 'Diorita Sewell' and 'Porfido Teniente' bodies, plus a series of minor plugs, apophyses and dikes. According to Cuadra (1986), the age of the main intrusive units spans from Late Miocene ('Diorita Sewell'; 7-8Ma) to Early Pliocene ('Porfido Teniente'; ∼4-5Ma). These felsic intrusives are closely related to copper mineralization ( ∼4-5Ma; Cuadra, 1986), particularly the younger 'Porfido Teniente' (Camus, 1975). Additionally, Skewes and Stern (1996) have suggested the existence of an even slightly younger porphyry pluton, not exposed at surface, but still linked to the ore genesis. Similar felsic intrusive bodies are also present in the Laguna La Huifa area (Reich, 2001), located less than 3 km to the NE from the main El Teniente body. The copper mineralization here, is interpreted to be almost contemporaneous with the El Teniente mineralization (Cuadra, 1986). Based on petrographic and geochemical information on the silicic intrusive suite, Rabbia et al. (2000) suggested that this magmatism could be considered as a Phanerozoic equivalent of an Archean high-Al TTG. Furthermore it may be classified as a modified (Na-rich) 'I' type granitoid, in the sense of Atherton and Petford (1993) and Petford and Atherton (1996). According to these authors, the younger (and hotter) lower Andean crust would be a better candidate than the older (and colder) subducted Nazca plate basalts (NPB

  9. Características de manejo y conducta en caballos estabulados en el sur de Chile: Estudio preliminar Husbandry and behaviour characteristics in stabled horses in the south of Chile: A preliminary study

    Directory of Open Access Journals (Sweden)

    C Márquez

    2010-01-01

    . In Chile the conditions under which horses are kept in stables in relation to welfare have not been described. This is why the main objective of this study was to describe the housing systems for horses used in the south of Chile and determine if they have the conditions required to maintain an adequate welfare status. Fourteen stud farms, including 283 horses of different breeds located in Valdivia, Ranco, Osorno and Chiloé provinces were visited. Direct and indirect methods were used for the evaluation; these included aspects of health, behaviour, handling of the horses and training of the personnel. According to our results most horses had a good body condition score (88%, 2.5% presented lesions and only 0.7% were lame. All stud farms had deworming schedules and the majority a vaccination programme. The main problems were related with the presence of behavioural disorders (18.4%, low number of food rations per day, size of the stables and lack of training of the personnel, especially in relation to animal welfare concepts. All stud farms had a high level of concern about the care of their horses. However, the lack of knowledge in some aspects related to horse management need to be addressed through training in order to improve horses welfare.

  10. Continuous Gravity Monitoring in South America with Superconducting and Absolute Gravimeters: More than 12 years time series at station TIGO/Concepcion (Chile)

    Science.gov (United States)

    Wziontek, Hartmut; Falk, Reinhard; Hase, Hayo; Armin, Böer; Andreas, Güntner; Rongjiang, Wang

    2016-04-01

    As part of the Transportable Integrated Geodetic Observatory (TIGO) of BKG, the superconducting gravimeter SG 038 was set up in December 2002 at station Concepcion / Chile to record temporal gravity variations with highest precision. Since May 2006 the time series was supported by weekly observations with the absolute gravimeter FG5-227, proving the large seasonal variations of up to 30 μGal and establishing a gravity reference station in South America. With the move of the whole observatory to the new location near to La Plata / Argentina the series was terminated. Results of almost continuously monitoring gravity variations for more than 12 years are presented. Seasonal variations are interpreted with respect of global and local water storage changes and the impact of the 8.8 Maule Earthquake in February 2010 is discussed.

  11. Photosynthetic performance of Colobanthus quitensis (Kunth Bartl. (Caryophyllaceae in a high-elevation site of the Andes of central Chile Desempeño fotosintético de Colobanthus quitensis (Kunth Bartl. (Caryophyllaceae en los Andes de Chile central

    Directory of Open Access Journals (Sweden)

    M. ANGÉLICA CASANOVA-KATNY

    2006-03-01

    Full Text Available Photosynthesis of Colobanthus quitensis and mesoclimatic conditions of air temperature and light intensity during the growing season were investigated at 2,650 m in the central Chilean Andes. On three typical days of the growing period (January, March and May, CO2 exchange and chlorophyll fluorescence were measured. In addition, a series of fluorescence response curves with increasing light intensity at different temperatures were performed to estimate the propensity of Andean C. quitensis populations to be photoinhibited. Net Photosynthesis (Pn was low (ca. 2.0 mmol CO2 m-2s-1 during the morning and noon in days with high photosynthetic active radiation (PAR, above 1,800 mmol photons m-2s-1. Pn increased in the afternoon (3.5-4.8 mmol CO2 m-2s-1 when PAR decreased to ca. 1,400 mmol photons m-2s-1 and leaf temperature were ca. 20 °C. Fv/Fm in the diurnal periods was between 0.7-0.75 without evidence of photoinhibition. Leaves at 15 and 22 °C exhibited a slow decrease of F PSII with the increase in actinic light intensity, although the fraction of reaction centers open (expressed by qP remained higher at 22 °C. NPQ was saturated at light intensities close to 500 mmol photons m-2s-1 in leaves at 22 °C and at higher intensities at 15 °C, suggesting that NPQ could be a mechanism of energy dissipation at high light intensity and high leaf temperature in the field. Our results indicated that C. quitensis is not photodamaged during the diurnal cycle and that the low Pn registered during some diurnal periods are likely to be related with photorespiration, which has been suggested as an efficient protective mechanism for photoinhibition in alpine plants. Our results are also compared with the photosynthetic performance of C. quitensis populations from the maritime AntarcticSe estudió la fotosíntesis de Colobanthus quitensis y las condiciones mesoclimáticas de temperatura del aire e intensidad lumínica a 2.650 m en los Andes de Chile central. Se

  12. Spatio-temporal variability in ontogenetic guild structure of an intertidal fish assemblage in central Chile Variabilidad espacio-temporal en la estructura de gremios ontogenéticos de un ensamble de peces intermareales de Chile central

    Directory of Open Access Journals (Sweden)

    PATRICIA A BERRÍOS

    2011-12-01

    variabilidad en las condiciones ambientales, especialmente en peces intermareales, los que alcanzan varios órdenes de magnitud en tamaño corporal. Sin embargo, la influencia de los cambios ontogenéticos en la membresía gremial sobre la estructura espacio-temporal de los ensambles de peces permanece virtualmente desconocida. En este trabajo estudiamos la variabilidad espacio-temporal en la estructura de los gremios alimenticios ontogenéticos (OFG de los ensambles de peces intermareales que ocurren en el intermareal rocoso de la costa de Chile central. Para esto realizamos an��lisis de componentes principales (PCA y pruebas de aleatorización (pruebas R de la composición relativa de las OFG de estos ensambles, obtenidos de muestreos estacionales en diez pozas intermareales ubicadas en dos alturas de mareas en la zona intermareal en tres localidades entre los 33° y 34° S. En general, los PCA y pruebas R sugieren que la variabilidad espacial domina sobre la variabilidad temporal en la estructura de las OFG, debido principalmente a la alta representatividad de las especies omnívoras en las pozas altas del intermareal en dos de las tres localidades muestreadas. Sin embargo, cambios relacionados a la fenología en la representación de las clases de tamaño de los peces (i.e. reclutamiento de carnívoros en primavera-verano junto con diferencias ontogenéticas en la selección de hábitat (e.g., selección por pozas del intermareal bajo por la OFG de carnívoros de gran tamaño contribuyeron a una diferenciación espacial y temporal de la estructura de la OFG. Finalmente, la representación relativa de cada OFG se correlacionó con la de sus especies dominantes, sin evidencia de una compensación por densidad. Esto sugiere bajos niveles de redundancia funcional entre las especies en cada OFG, lo cual denota la vulnerabilidad del funcionamiento de estos ensambles a perturbaciones sesgadas en tamaño corporal tales como la pesca.

  13. Seismicity and plate tectonics in south central Alaska

    Science.gov (United States)

    Van Wormer, J. D.; Davies, J.; Gedney, L.

    1974-01-01

    Hypocenter distribution shows that the Benioff zone associated with the Aleutian arc terminates in interior Alaska some 75 km north of the Denali fault. There appears to be a break in the subducting Pacific plate in the Yentna River-Prince William Sound area which separates two seismically independent blocks, similar to the segmented structure reported for the central Aleutian arc.

  14. Multi-element stream sediment geochemistry of south-western and central Nigeria

    OpenAIRE

    Knights, K.V.; Lapworth, D. J.; Key, R. M.; Johnson, C C; Adekanmi, M.A.; Arisekola, T.M.

    2011-01-01

    This paper presents preliminary results from geochemical baseline stream sediment surveys from two Cells (South-western Cell and Central Cell) in Nigeria completed in 2009. This work was part of the World Bank funded Nigerian Sustainable Management of Mineral Resources Project carried out by the Nigerian Geological Survey Agency in cooperation with the British Geological Survey. A total of 284 stream sediment samples were collected from the South-western Cell, with an average sampling density...

  15. Satellite-measured interannual variability of turbid river plumes off central-southern Chile: Spatial patterns and the influence of climate variability

    Science.gov (United States)

    Saldías, Gonzalo S.; Largier, John L.; Mendes, Renato; Pérez-Santos, Iván; Vargas, Cristian A.; Sobarzo, Marcus

    2016-08-01

    Ocean color imagery from MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the Aqua platform is used to characterize the interannual variability of turbid river plumes off central-southern Chile. Emphasis is placed on the influence of climate fluctuations, namely El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Antarctic Oscillation (AAO). Additional satellite data on wind, boat-based hydrographic profiles, and regional climate indices are used to identify the influence of climate variability on the generation of anomalous turbid river plumes. The evolution of salinity at a coastal station on the 90 m isobath between the Itata and Biobío Rivers shows a freshwater surface layer with salinity importance of long-term and high-resolution ocean color observations for studying the temporal evolution of river plumes.

  16. Talla de madurez y época de desove de la reineta (Brama australis Valenciennes, 1836) en la costa central de Chile Maturity size and spawning time of the Pacific pomfret (Brama australis Valenciennes, 1836) in the central coast of Chile

    OpenAIRE

    Elson Leal; Ciro Oyarzún

    2003-01-01

    La reineta (Brama australis) adquiere cada vez mayor importancia en los desembarques de la pesca artesanal, no obstante, es escasa la información que existe acerca de su biología básica, particularmente sobre su dinámica reproductiva. En este trabajo se determina la época principal de desove de B. australis en la costa central de Chile y la talla de madurez (TM), para lo cual se analizó un total de 1061 individuos capturados frente a Lebu (37º37'S-73º40'W), entre enero y septiembre de 2001. E...

  17. Shoreline changes in Concón and Algarrobo bays, central Chile, using an adjustment model Cambios en la línea litoral de las bahías de Algarrobo y Concón, Chile central, a través de un modelo de ajuste

    OpenAIRE

    Carolina Martinez

    2007-01-01

    Adjustment models for both Algarrobo and Concón bays, central Chile, are presented herein; the results show a nearly logarithmic spiral shape for the shore. Spatial-temporal variations in the shorelines of both bays were found based on aerial photographs from different years. The results indicate important variations in the relative position of the Concón Bay shoreline between 1945 and 2006, with extreme oscillations (-368 to 123.8 m) only occurring in the proximal zone, where the Aconcagua E...

  18. Evolución tectónica, paleogeográfica y metalogénica durante el Cenozoico en los Andes de Chile norte y central e implicaciones para las regiones adyacentes de Bolivia y Argentina Tectonic, paleogeographic, and metallogenic evolution during the Cenozoic in the Andes of Central and Northern Chile and implication for the adjacent regions of Bolivia and Argentina

    OpenAIRE

    Reynaldo Charrier; Marcelo Farías; Víctor Maksaev

    2009-01-01

    La orogenia incaica dio origen a un importante relieve en el Eoceno Medio, el que se concentró en el ámbito del arco magmático precedente, la Cordillera Incaica. Este relieve positivo de orientación NNE se extendió desde el sur de Perú hasta la región central de Chile y separó dos dominios paleogeográficos que tuvieron evoluciones diferentes durante el resto del Cenozoico. El dominio occidental se caracterizó por el predominio de procesos de erosión y sedimentación. En el dominio oriental tam...

  19. Preliminary geology of eastern Umtanum Ridge, South-Central Washington

    International Nuclear Information System (INIS)

    The basalt stratigraphy and geologic structures of eastern Umtanum Ridge have been mapped and studied in detail to help assess the feasibility of nuclear waste terminal storage on the Hanford Site in southeastern Washington State. Eastern Umtanum Ridge is an asymmetric east-west-trending anticline of Columbia River basalt that plunges 5 degrees eastward into the Pasco Basin. Geologic mapping and determination of natural remanent magnetic polarity and chemical composition reveal that flows of the Pomona and Umatilla Members (Saddle Mountains Basalt), Priest Rapids and Frenchman Springs Members (Wanapum Basalt), and Grande Ronde Basalt were erupted as fairly uniform sheets. The Wahluke and Huntzinger flows (Saddle Mountains Basalt) fill a paleovalley cut into Wanapum Basalt. No evidence was found to indicate Quaternary-age movement on any structures in the map area. The basalt strata on the south limb of the Umtanum anticline display relatively little tectonic deformation since Miocene-Pliocene time. Thus, the buried south flank of Umtanum Ridge may provide an excellent location for a nuclear waste repository beneath the Hanford Site

  20. Preliminary geology of eastern Umtanum Ridge, South-Central Washington

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F.E.

    1981-01-01

    The basalt stratigraphy and geologic structures of eastern Umtanum Ridge have been mapped and studied in detail to help assess the feasibility of nuclear waste terminal storage on the Hanford Site in southeastern Washington State. Eastern Umtanum Ridge is an asymmetric east-west-trending anticline of Columbia River basalt that plunges 5 degrees eastward into the Pasco Basin. Geologic mapping and determination of natural remanent magnetic polarity and chemical composition reveal that flows of the Pomona and Umatilla Members (Saddle Mountains Basalt), Priest Rapids and Frenchman Springs Members (Wanapum Basalt), and Grande Ronde Basalt were erupted as fairly uniform sheets. The Wahluke and Huntzinger flows (Saddle Mountains Basalt) fill a paleovalley cut into Wanapum Basalt. No evidence was found to indicate Quaternary-age movement on any structures in the map area. The basalt strata on the south limb of the Umtanum anticline display relatively little tectonic deformation since Miocene-Pliocene time. Thus, the buried south flank of Umtanum Ridge may provide an excellent location for a nuclear waste repository beneath the Hanford Site.

  1. Tectonic styles and crustal shortening of the Central Andes "Pampean" flat-slab segment in northern Chile (27-29°S)

    Science.gov (United States)

    Martínez, Fernando; Arriagada, César; Peña, Matías; Deckart, Katja; Charrier, Reynaldo

    2016-01-01

    The Andean orogenic belt, located in the Central Andes "Pampean flat-slab" segment in northern Chile (27-29°S), is composed of two major tectonic regions: the Coastal Cordillera and the Frontal Cordillera. To understand their internal tectonic styles, history of growth and the shortening absorbed by the upper crustal structure of this segment, we combined regional geological mapping data, new ages obtained from radiometric U-Pb dating, and a semibalanced and restored cross-section 225.18 km in length. The results as shown in the previous Mesozoic extensional fault systems, established in northern Chile by the Gondwana breakup, have played a fundamental role in the orogenic buildup. The central structure is characterized by an asymmetric basin (Upper Cretaceous-Paleocene) confined by a doubly vergent fault system composed of inverted faults related to the edges of the Mesozoic Chañarcillo and Lautaro Basins. The U-Pb geochronological data obtained from synorogenic volcano-sedimentary deposits and the angular unconformities recorded between the Cenozoic geological units have revealed that the compressive deformation in this segment started at around ~ 80 Ma by tectonic inversion in the eastern Coastal Cordillera and western Frontal Cordillera, however, the presence of Paleocene and Miocene synorogenic successions at the footwall of the basement reverse faults of the Frontal Cordillera suggests a migration of Andean deformation from the west to the east during the Paleocene-Miocene by propagation of ramps involving inherited basement highs. The pre-compression restoration makes it possible to estimate 40.94 km of minimum shortening, concentrated by inversion anticlines and fault-controlled basement highs across the Frontal Cordillera.

  2. Distribución del ictioplancton en la Patagonia austral de Chile: potenciales efectos del deshielo de Campos de Hielo Sur Ichthyoplankton distribution in South Patagonia, Chile: potential effects of ice melting from the Southern Ice Field

    Directory of Open Access Journals (Sweden)

    Mauricio F Landaeta

    2011-07-01

    Full Text Available Durante octubre-noviembre de 2009 se realizó un crucero oceanográfico entre 50 y 53°S de Chile austral, en las cercanías del glaciar Campos de Hielo Sur. Las estaciones cercanas al glaciar presentaron baja temperatura (1-3°C y salinidad ( 0,1 ciclos s-1. Los principales taxa del ictioplancton fueron huevos y larvas de sardina fueguina Sprattus fuegensis, pez hacha Maurolicus parvipinnis, Macrouridae y merluza austral Merluccius australis. El desove principal de S. fuegensis (~ 8000 huevos 10 m-2 ocurrió en zonas mezcladas de la plataforma continental adyacente, mientras que el desove de M. parvipinnis ocurrió en canales intermedios asociado a valores intermedios de estabilidad (N~0,06 ciclos s-1. Se observó una nula o baja abundancia de huevos y larvas de peces en las cercanías del glaciar, y la abundancia de huevos de M. parvipinnis estuvo relacionada positivamente con la temperatura y salinidad de la columna de agua y negativamente con la estabilidad de la columna de agua. Además, hubo una relación negativa entre la densidad del agua de mar y el diámetro de los huevos de S. fuegensis. La relación entre deshielo e ictioplancton podría tener consecuencias en el transporte advectivo y mortalidad masiva de huevos y larvas de peces y el acople pelágico-bentónico en la Patagonia austral de Chile. Como el cambio climático global ha incrementado los deshielos de glaciares en latitudes altas, y el aumento del ingreso de aguas de baja temperatura y salinidad podría tener consecuencias en el ictioplancton de la Patagonia chilena.In October-November 2009, an oceanographic survey was carried out between 50 and 53°S off southern Chile, near the Southern Ice Field. The stations near the glacier showed low temperatures (1-3°C and salinity ( 0.1 cycles s-1. Main ichthyoplankton taxa were eggs and larvae of southern sprat Sprattus fuegensis, lightfish Maurolicus parvipinnis, Macrouridae, and southern hake Merluccius australis. The main

  3. Prospección del manejo y utilización de efluentes de lecherías en el sur de Chile A survey of dairy effluent management in the south of Chile

    Directory of Open Access Journals (Sweden)

    F. J. SALAZAR

    2003-12-01

    Full Text Available RESUMEN Se realizó una encuesta a predios lecheros ubicados en la Décima Región de Chile durante el período 1995-97. Para la colecta de información se confeccionó un cuestionario, el cual permitió recopilar información referente al manejo y utilización de los efluentes de lechería en estos predios. La información fue analizada con la ayuda de una planilla electrónica que permitió relacionar los distintos parámetros encuestados. Además, en cada visita a los predios se colectó una muestra para determinar el contenido de materia seca del efluente. Los resultados de este estudio muestran que una gran proporción de los efluentes se genera producto del agua lluvia (47% y aguas sucias del lavado de equipos y pisos (29%, y sólo un 24% es producto de las fecas y orina. Los grandes volúmenes de efluentes producidos implican una reducida capacidad de almacenamiento de los pozos (en promedio dos meses o más frecuentes y altas dosis de las aplicaciones. Sólo un 37% de los agricultores encuestados conocían las dosis de efluentes empleadas, existiendo una gran variación en los volúmenes aplicados anualmente (entre 12 m3/ha y 300 m³/ha. Los efluentes se utilizan preferentemente en la fertilización de praderas (71% a través de aplicaciones durante todo el año con el uso de equipos de aplicación en superficie, siendo las aplicaciones concentradas principalmente en invierno y primavera. El contenido de materia seca de los efluentes es muy bajo, con un 62% de las muestras presentando valores menores a 4%, lo cual refleja los grandes volúmenes de agua extra que ingresan al pozo. La información de este estudio ha permitido identificar problemas en el manejo y utilización de efluentes en sistemas lecheros en Chile, donde el desarrollo de investigación y la transferencia de tecnologías serán necesarias para evitar problemas de contaminación.SUMMARY A survey was carried out on 55 commercial dairy farms located in the South of Chile

  4. Oil and Gas Emergency Policy: Chile 2012 update

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-06

    Chile has experienced several serious energy supply incidents over the last decade, including major droughts, a sustained gas supply cut from Argentina (since 2004), and a major earthquake in early 2010 which affected electricity networks and refineries, and caused several black-outs. Due to Chile's unique and sinuous geography - it runs 4 300 kilometres from North to South and only 175 kms from East to West- the country's energy markets are regionally disjointed, particularly as the regional gas and electricity grids are not connected. In the arid North, energy demand is dominated by the mining industry, and operates based on a separate thermal-based Sistema Interconectado Norte Grande (SING) electricity grid. The more densely-populated central region (including Santiago) operates on the more hydro-dependent Sistema Interconectado Central (SIC) electricity grid. The southernmost, hydro-rich regions of the country are not connected to the rest of Chile in terms of electricity and gas. The following report is based on an IEA Emergency Response Assessment carried out in 2010 and 2011 which looked specifically at Chile's capacity to respond to short-term emergencies in oil, gas and electricity.

  5. Late Cenozoic structure and stratigraphy of south-central Washington

    International Nuclear Information System (INIS)

    The structural framework of the Columbia Basin began developing before Columbia River Basalt Group (CRBG) volcanism. Prior to 17.5 Ma, the eastern part of the basin was a relatively stable area, with a basement of Paleozoic and older crystalline rock. The western part was an area of subsidence in which large volumes of sediment and volcanic rocks accumulated. Concurrent with eruption of the CRBG, anticlinal ridges of the Yakima Fold Belt (YFB) were growing under north-south compression. Topographic expression of these features was later masked by the large volume of CRBG basalt flowing west from fissures in the eastern Columbia Basin. The folds continued to develop after cessation of volcanism, leading to as much as 1,000 m of structural relief in the past 10 million years. Post-CRBG evolution of the Columbia Basin is recorded principally in folding and faulting in the YFB and sediments deposited in the basins. The accompanying tectonism resulted in lateral migration of major depositional systems into subsiding structural lows. Although known late Cenozoic faults are on anticlinal ridges, earthquake focal mechanisms and contemporary strain measurements indicate most stress release is occurring in the synclinal areas under north-south compression. There is no obvious correlation between focal mechanisms for earthquakes whose foci are in the CRBG and the location of known faults. High in situ stress values help to explain the occurrence of microseismicity in the Columbia Basin but not the pattern. Microseismicity appears to occur in unaltered fresh basalt. Faulted basalt associated with the YFB is highly brecciated and commonly altered to clay. The high stress, abundance of ground water in confined aquifers of the CRBG, and altered basalt in fault zones suggest that the frontal faults on the anticlinal ridges probably have some aseismic deformation. 85 refs

  6. Productivity and Persistence of Yellow Serradela (Ornithopus compressus L. and Biserrula (Biserrula pelecinus L. in the Mediterranean Climate Region of Central Chile Productividad y Persistencia de Serradela Amarilla (Ornithopus compressus L. y Biserrula (Biserrula pelecinus L. en la Región Climática Mediterránea de Chile Central

    Directory of Open Access Journals (Sweden)

    Alejandro del Pozo

    2009-09-01

    Full Text Available The production and sustainability of non-irrigated pastures in the Mediterranean climate region of central Chile is currently limited by the low diversity of valuable species and cultivars of annual forage legumes, able to persist in zones with highly variable annual rainfall, and low fertility or poorly drained soils. In this work, DM production, seed yield, hardseededness and pasture persistence were evaluated for cultivars of yellow serradella (Ornithopus compressus L. and biserrula (Biserrula pelecinus L., in field experiments conducted in the subhumid portion of the Mediterranean climate region of Chile. Burr medic (Medicago polymorpha L. and sub clover (Trifolium subterraneum L. were used as a reference plants. A remarkable DM production and seed yield were observed in biserrula (cvs. Mor96 and Casbah, and in some cultivars of yellow serradella (e.g. Madeira, Santorini; biserrula produced by far the largest number of seeds per m². As was expected for species that produce very high levels of hard-seeds, the regeneration of biserrula and serradella was low in second growing season, but plant density and productivity were high in the third growing season. The use of biserrula and serradela in monoculture or in mixture with other annual legumes, either in pasture-crop rotation or permanent pasture, would contribute to the improvement of the prevailing productive systems in the Mediterranean climate region of central Chile.La producción y la sostenibilidad de las praderas de secano en la región de clima mediterráneo de Chile central están actualmente limitadas por la baja diversidad de especies valiosas y cultivares de leguminosas forrajeras anuales, capaces de persistir en zonas con precipitaciones anuales sumamente variables, y suelos de baja fertilidad o de mal drenaje. En este trabajo se evaluó la producción de fitomasa, producción de semilla, dureza seminal y la persistencia de cultivares de serradela amarilla (Ornithopus

  7. Crypsis in early benthic phases of Brachyuran Decapod Crustaceans in central Chile Cripsis en fases bentónicas tempranas de crustáceos decápodos braquiuros en Chile central

    Directory of Open Access Journals (Sweden)

    ÁLVARO T. PALMA

    2003-06-01

    Full Text Available Although common and in some cases of commercial value, little is known about the mechanisms and processes that affect the distribution and abundance of many species of decapod crustaceans, particularly in Chile. All of these species have planktonic larvae that must settle and recruit before becoming part of the adult segments of their populations. For several of these species we have detected the presence of a variety of color morphs in newly settled individuals. The existence of these morphs in Chilean species is comparable with those observed in other latitudes (e.g., coast of the Gulf of Maine. On the other hand, it is characteristic that the occurrence of these patterns only appears during the early juvenile stages and that after reaching a certain size it disappears, with adults being typically monochromatic. The expression of this pattern in the Chilean subtidal seems to be more pronounced in detritivorous species than in carnivorous ones. We propose that the existence of these kind of phenotypic attributes, apparently generalized in brachyuran decapods, could play an important role both from an ecological as well as evolutionary point of viewAunque comunes, y en algunos casos de valor comercial, poco es lo que se conoce acerca de los mecanismos y procesos que afectan la distribución y abundancia de muchas especies de crustáceos decápodos, particularmente en Chile. Todas estas especies poseen larvas planctónicas que deben asentarse y reclutar antes de pasar a formar parte de los segmentos adultos de sus poblaciones. En varias de estas especies hemos detectado la presencia de una variedad de morfos de coloración en individuos recién asentados. La existencia de dichos morfos en especies chilenas es comparable con aquellos observados en otras latitudes (e.g., costa del Golfo de Maine. Por otro lado, es característica la aparición de estos patrones solo durante los estadíos juveniles tempranos y, al alcanzar cierto tamaño, estos

  8. The tomato borer, Tuta absoluta, invading the Mediterranean Basin, originates from a single introduction from Central Chile

    OpenAIRE

    Thomas Guillemaud; Aurélie Blin; Isabelle Le Goff; Nicolas Desneux; Maritza Reyes; Elisabeth Tabone; Anastasia Tsagkarakou; Laura Niño; Eric Lombaert

    2015-01-01

    The Lepidopteran pest of tomato, Tuta absoluta, is native to South America and is invasive in the Mediterranean basin. The species' routes of invasion were investigated. The genetic variability of samples collected in South America, Europe, Africa and Middle East was analyzed using microsatellite markers to infer precisely the source of the invasive populations and to test the hypothesis of a single versus multiple introductions into the old world continents. This analysis provides strong evi...

  9. Presencia del tiburón martillo Sphyrna zygaena (Carchariniformes: Sphyrnidae y nuevo registro del tiburón espinudo Echinorhinus cookei (Squaliformes: Squalidae en San Antonio, Chile central Presence of the smooth hammerhead Sphyrna zygaena (Carchariniformes: Sphyrnidae and new records of prickly shark Echinorhinus cookei (Squaliformes: Squalidae in San Antonio, central Chile

    Directory of Open Access Journals (Sweden)

    José L. Brito

    2004-11-01

    Full Text Available Se documenta el registro de Sphyrna zygaena (Linnaeus, 1758, sobre la base de un ejemplar capturado en la bahía de San Antonio (33°35'S y un ejemplar de Echinorhinus cookei Pietschmann, 1928, capturado al oeste de Santo Domingo (33°37'S. En el primer caso, se amplía su distribución geográfica desde Arica hasta San Antonio, y en el segundo, se agrega un quinto registro para esa especie en aguas chilenasThe sighting of Sphyrna zygaena (Linnaeus, 1758 based on the capture of a specimen in the bay of San Antonio (33°35'S and a specimen of Echinorhinus cookei Pietschmann, 1928 captured to the west of the coast of Santo Domingo (33°35'S. The former case, the known geographic distribution is increased from region to the north to San Antonio, in central Chile and in the alter, a fifth sighting is noted for the species in Chilean waters, confirming its presence in the central region of Chile

  10. Atrazine in Source Water Intended for Artificial Ground-Water Recharge, South-Central Kansas

    Science.gov (United States)

    Christensen, Victoria G.; Ziegler, Andrew C.

    1998-01-01

    Atrazine, an herbicide commonly applied to row crops, is of concern because of potential effects on water quality. This fact sheet describes atrazine in water from the Little Arkansas River in south-central Kansas. The river is being evaluated as a source of artificial recharge into the Equus Beds aquifer, which provides water for the city of Wichita.

  11. Detection of East/Central/South African Genotype of Chikungunya Virus in Myanmar, 2010

    OpenAIRE

    Tun, Mya Myat Ngwe; Thant, Kyaw Zin; Inoue, Shingo; Nabeshima, Takeshi; Aoki, Kotaro; Kyaw, Aung Kyaw; Myint, Tin; Tar, Thi; Maung, Kay Thwe Thwe; Hayasaka, Daisuke; Morita, Kouichi

    2014-01-01

    In 2010, chikungunya virus of the East Central South African genotype was isolated from 4 children in Myanmyar who had dengue-like symptoms. Phylogenetic analysis of the E1 gene revealed that the isolates were closely related to isolates from China, Thailand, and Malaysia that harbor the A226V mutation in this gene.

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

    Directory of Open Access Journals (Sweden)

    2006-12-01

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

  13. Air quality forecasting for winter-time PM2.5 episodes occurring in multiple cities in central and southern Chile

    Science.gov (United States)

    Saide, Pablo E.; Mena-Carrasco, Marcelo; Tolvett, Sebastian; Hernandez, Pablo; Carmichael, Gregory R.

    2016-01-01

    Episodic air quality degradation due to particles occurs in multiple cities in central and southern Chile during the austral winter reaching levels up to 300-800 µg/m3 hourly PM2.5, which can be associated with severe effects on human health. An air quality prediction system is developed to predict such events in near real time up to 3 days in advance for nine cities with regular air quality monitoring: Santiago, Rancagua, Curicó, Talca, Chillan, Los Ángeles, Temuco, Valdivia, and Osorno. The system uses the Weather Research and Forecasting with Chemistry model configured with a nested 2 km grid-spacing domain to predict weather and inert tracers. The tracers are converted to hourly PM2.5 concentrations using an observationally based calibration which is substantially less computationally intensive than a full chemistry model. The conversion takes into account processes occurring in these cities, including higher likelihood of episode occurrence during weekends and during colder days, the latter related to increased wood-burning-stove activity for heating. The system is calibrated and evaluated for April-August 2014 where it has an overall skill of 53-72% of episodes accurately forecasted (61-76% for the best initialization) which is better than persistence for most stations. Forecasts one, two, and three days in advance all have skill in forecasting events but often present large variability within them due to different meteorological initializations. The system is being implemented in Chile to assist authority decisions not only to warn the population but also to take contingency-based emission restrictions to try to avoid severe pollution events.

  14. Comparison of Airborne LiDAR and Satellite Hyperspectral Remote Sensing to Estimate Vascular Plant Richness in Deciduous Mediterranean Forests of Central Chile

    Directory of Open Access Journals (Sweden)

    Andrés Ceballos

    2015-03-01

    Full Text Available The Andes foothills of central Chile are characterized by high levels of floristic diversity in a scenario, which offers little protection by public protected areas. Knowledge of the spatial distribution of this diversity must be gained in order to aid in conservation management. Heterogeneous environmental conditions involve an important number of niches closely related to species richness. Remote sensing information derived from satellite hyperspectral and airborne Light Detection and Ranging (LiDAR data can be used as proxies to generate a spatial prediction of vascular plant richness. This study aimed to estimate the spatial distribution of plant species richness using remote sensing in the Andes foothills of the Maule Region, Chile. This region has a secondary deciduous forest dominated by Nothofagus obliqua mixed with sclerophyll species. Floristic measurements were performed using a nested plot design with 60 plots of 225 m2 each. Multiple predictors were evaluated: 30 topographical and vegetation structure indexes from LiDAR data, and 32 spectral indexes and band transformations from the EO1-Hyperion sensor. A random forest algorithm was used to identify relevant variables in richness prediction, and these variables were used in turn to obtain a final multiple linear regression predictive model (Adjusted R2 = 0.651; RSE = 3.69. An independent validation survey was performed with significant results (Adjusted R2 = 0.571, RMSE = 5.05. Selected variables were statistically significant: catchment slope, altitude, standard deviation of slope, average slope, Multiresolution Ridge Top Flatness index (MrRTF and Digital Crown Height Model (DCM. The information provided by LiDAR delivered the best predictors, whereas hyperspectral data were discarded due to their low predictive power.

  15. VariaciOn morfolOgica de Phacelia secunda J.F. Gmel. (Hydrophyllaceae a lo largo de un gradiente a ltitudinal en Chile central Morphological variation of Phacelia secunda J.F. Gmel. (Hydrophyllaceae along an altitudinal gradient in central Chile

    Directory of Open Access Journals (Sweden)

    Lohengrin A. Cavieres

    2000-01-01

    Full Text Available Phacelia secunda J.F. Gmel. (Hydrophyllaceae es una hierba perenne que en Chile, y también en Argentina, presenta una amplia distribución, habitando desde Parinacota (18°S hasta Tierra del Fuego (54°S, y desde el nivel del mar hasta la alta cordillera. En este estudio se documentan algunas variaciones morfológicas que presenta esta especie a lo largo de un gradiente altitudinal desde los 1.600 m a los 3.400 m en los Andes de Chile central (33°S. Se encontró que el diámetro de las rosetas aumenta significativamente con la altitud, al igual que el número de inflorescencias por individuo y la longitud de la pubescencia. Por el contrario, la altura de las inflorescencias disminuye con la altitud. La tendencia a privilegiar el crecimiento vertical a bajas altitudes y el crecimiento horizontal en altitudes mayores sería una respuesta adaptativa a las frías condiciones de los ambientes de alta montaña. Del mismo modo, el aumento en la longitud de la pubescencia con la altitud sería una adaptación para mantener un balance térmico positivo y evitar los excesos de radiación en dichos ambientesPhacelia secunda J.F. Gmel. (Hydrophyllaceae is a perennial herb that both, in Chile and Argentina, shows a wide distributional range, inhabiting from Parinacota (18°S to Tierra del Fuego (54°S, and from the sea level up to the high Andes. In this study some morphological variations along an altitudinal gradient from 1600 to 3400 m in Andes of central Chile (33°S are reported. The diameter of the rosettes significantly increased with elevation, as well as the number of inflorescences per individual and the longitude of pubescence. In contrast, the height of inflorescences decreased with elevation. Tendencies for privileging vertical growth at lower elevations and horizontal growth at higher elevations would be adaptations to the cold and harsh climate of high mountain habitats. In a similar vein, the increase in the longitude of pubescence with

  16. Determination of trace elements in Pre-Hispanic ceramics from Chile's Central Zone using instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    The determination of the element composition in archaeological ceramics is an often unexplored potential, that could provide a unique set of data to verify regional economic and socio-political hypotheses. By chemically defining the elements in these materials, their manufacturing and production centers may be identified, as well as the territorial and social organization of the peoples. Appropriate analytical methodologies for this type of research are limited since there are strict requirements with reference to precision, sensitivity and detection limits, all characteristics that the activation analysis technique provides. The Chilean Nuclear Energy Commission, the University of Chile, the Smithsonian Institution and the International Atomic Energy Agency developed together a cooperative interregional project to promote interdisciplinary research, to resolve archaeological problems and to develop a new application for a nuclear analytical technique. Until this work was undertaken, no systematic studies of trace elements in archaeological ceramics had been done in Chile using the technique of Instrumental Neutron Activation Analysis (INAA). This analytical technique was used in this research to chemically characterize archaeological pieces with the sensitivity, precision and accuracy needed to be able to work with mathematical models that can or cannot establish relationships between the different samples. Protocols were defined first for preparing the pottery samples in order to generate representative samples that could be analyzed by INAA. The homogeneity in preparing the samples used was defined using a group of elements that could be determined by INAA with a precision under 2%. A group of 18 elements was selected and an analytical test procedure was planned that included the type of packaging for the irradiation, the irradiation times, decline and count, the standards to be used and the type of monitor for correcting the neutron flow. The methodology used

  17. Distribution of planktonic cnidarians in response to South Atlantic Central Water intrusion in the South Brazilian Bight

    Science.gov (United States)

    Nogueira Júnior, Miodeli; Brandini, Frederico P.; Codina, Juan C. U.

    2014-10-01

    Five oceanographic cruises were made between November 2005 and June 2006, sampling a cross-shelf transect off the South Brazilian Bight (SBB; 26°46‧S) to follow the seasonal development of the South Atlantic Central Water (SACW) intrusion over the shelf and its influence on the assemblage of planktonic cnidarians. An onshore wind-driven bottom intrusion of the SACW was clearly perceptible, reaching the coast in January. From March onward, the SACW influence was gradually displaced seaward due to wind and tidal mixing. By late June the SACW influence was offshore and the inshore was dominated by low-salinity waters (20 mm in diameter) Solmaris corona were observed exclusively in cold waters, suggesting this medusa is a SACW indicator.

  18. Polyphenol content and antioxidant activity of maqui (Aristotelia chilensis Molina Stuntz during fruit development and maturation in Central Chile Contenidos de polifenoles y actividad antioxidante de maqui (Aristotelia chilensis Molina Stuntz durante el desarrollo y maduración de frutos en Chile Central

    Directory of Open Access Journals (Sweden)

    Carolina Fredes

    2012-12-01

    Full Text Available Maqui (Aristotelia chilensis Molina Stuntz, Elaeocarpaceae is a Chilean native species which produces small berries that are mainly collected from the wild. The health benefits of maqui fruit are attributed to their high polyphenol content as well as their wide variety of anthocyanins and flavonols. One of the main factors that affect the polyphenol content in fruit is the maturity stage at harvest. The objective of this study was to determine total phenol and total anthocyanin content and antioxidant activity (by ferric reducing ability of plasma FRAP assay of maqui fruits harvested at different fruit maturity stages from two wild populations located in Central Chile. Each maturity stage was determined by days from fruit set, berry size, and soluble solids. Total phenol content declined while total anthocyanin content increased from the green to light red stage. Nevertheless, both total phenol and anthocyanin content increased from the light red to dark purple stage. The highest anthocyanin content and antioxidant activity was found in the late maturity stage (dark purple. The results show that ripening in maqui fruit can be expected with 1100 growing degree-days (91 d after fruit set in Central Chile. At this moment of harvest, fruits with 18-19 °Brix have the highest anthocyanin content and antioxidant activity (FRAP. This study constitutes the first advances in the understanding of maqui fruit ripening and corresponding antioxidant activity.El maqui (Aristotelia chilensis Molina Stuntz, Elaeocarpaceae es una especie nativa de Chile que produce unas bayas pequeñas que se recolectan principalmente de individuos silvestres. Los beneficios para la salud atribuidos a los frutos de maqui se deben a sus altos contenidos de polifenoles, así como a la gran variedad de antocianos y flavonoles. Uno de los principales factores que afectan el contenido de polifenoles en frutos es el estado de madurez a la cosecha. El objetivo de este estudio fue

  19. Estudio del comportamiento serológico de Actinobacillus pleuropneumoniae (App en planteles porcinos comerciales de la zona central de Chile Serological behaviour study of Actinobacillus pleuropneumoniae (App in commercial swine herds from the central region of Chile

    Directory of Open Access Journals (Sweden)

    D Muñoz

    2008-01-01

    Full Text Available En Chile se ha realizado sólo un estudio en Actinobacillus pleuropneumoniae (App. Este trabajo pretende determinar la duración de la inmunidad materna, la edad de seroconversión y la prevalencia aparente y verdadera en 7 planteles de cerdos comerciales. Se obtuvieron 60 muestras por plantel, divididas en 10 muestras de suero, de animales de 4, 6, 10, 14,18 y 21 semanas de edad, y analizadas a través de un kit ELISA® comercial. De las 420 muestras se detectaron 134 positivas, de las cuales 112 correspondían a cerdos menores de 10 semanas y sólo 22 provenían de animales mayores de 10 semanas, que seroconvirtieron probablemente debido a una infección de campo. La caída de la inmunidad materna fue alrededor de la 10ª semana de edad. En cuanto a la seroconversión, se observó que a partir de la 18* semana comenzaron a aparecer los animales con anticuerpos circulantes propios. Dos de los siete planteles no seroconvirtieron. Además, dos presentaron una seroconversión igual o superior al 50% a las 18 semanas. La seroprevalencia aparente de App fue de 10,48%, mientras que prevalencia verdadera, mediante dos métodos estadísticos, fue de 9,6% (IC: 7,6% y 11,7% y 10,67% respectivamente. En este trabajo se encontró que la prevalencia es similar a la observada en EE.UU., debido presumiblemente al sistema de producción y a los serotipos que están presentes en ambos países. Por otro lado, si bien la mayoría de los planteles seroconvierten luego de la caída de la inmunidad materna, se observaron diferentes patrones serológicos entre ellos.In Chile, there was only one existing study on App. This study was designed to determine the maternal immunity duration, the age of seroconversion and the apparent and true prevalence in animals from 7 swine commercial herds. 60 samples were taken per herd and divided into 10 serum samples from animals of 4, 6,10,14,18and21 weeks of age, which were analyzed by ELISA®. Out of the 420 samples, 134 were

  20. Breeding distribution and abundance of seabirds on islands off north-central Chile Distribución reproductiva y abundancia de aves marinas en islas del norte y centro de Chile

    Directory of Open Access Journals (Sweden)

    ALEJANDRO SIMEONE

    2003-06-01

    Full Text Available Between 1999 and 2003 we collected information on the breeding distribution and abundance of 12 seabird species occurring on nine islands off the coasts of north and central Chile (27°-33°S. The Peruvian booby Sula variegata was the most abundant seabird with a breeding population of ca. 18,000 pairs concentrated in two islands, followed by the Humboldt penguin Spheniscus humboldti with ca. 9,000 pairs, the largest colony being at Chañaral Island with ca. 7,000 pairs. Kelp gulls Larus dominicanus bred at all the surveyed sites in colonies of variable size, ranging from 40 to 2,000 pairs. Peruvian diving-petrels Pelecanoides garnotii and Peruvian pelicans Pelecanus occidentalis bred at restricted sites, but generally in large colonies. Magellanic penguins Spheniscus magellanicus, wedge-rumped storm-petrels Oceanodroma tethys, Neotropical cormorants Hypoleucos brasiliensis, guanay cormorants Leucocarbo bougainvillii, red-legged cormorants Stictocarbo gairmardi, band-tailed gulls Larus belcheri and Inca terns Larosterna inca nested at few sites forming small colonies (from a few to 150 pairs. Two new breeding sites are reported for the Peruvian diving-petrel and nesting of the wedge-rumped storm-petrel is confirmed on the Chilean coast for the first time. Despite protective status, most of the islands showed human disturbance, derived mainly from guano harvesting, egging and tourism. On at least five of these islands we were able to confirm introduced mammals including rats, rabbits and cats. These factors are likely to be detrimental to seabirds and thus demand detailed assessment. Further comprehensive ornithological surveys in other areas are needed so as to improve the scarce knowledge that we currently have on the seabird populations along the Chilean coast

  1. Fungal parasites infect marine diatoms in the upwelling ecosystem of the Humboldt current system off central Chile.

    Science.gov (United States)

    Gutiérrez, Marcelo H; Jara, Ana M; Pantoja, Silvio

    2016-05-01

    This is the first report of fungal parasitism of diatoms in a highly productive coastal upwelling ecosystem, based on a year-round time series of diatom and parasitic Chytridiomycota abundance in the Humboldt Current System off Chile (36°30.80'S-73°07.70'W). Our results show co-variation in the presence of Skeletonema, Thalassiosira and Chaetoceros diatoms with attached and detached chytrid sporangia. High abundance of attached sporangia was observed during the austral spring, coinciding with a predominance of Thalassiosira and Skeletonema under active upwelling conditions. Towards the end of austral spring, a decreasing proportion of attached sporangia was accompanied by a decline in abundance of Skeletonema and Thalassiosira and the predominance of Chaetoceros, suggesting specificity and host density dependence of chytrid infection. The new findings on fungal parasitism of diatoms provide further support for the inclusion of Fungi in the current model of the role played by the marine microbial community in the coastal ocean. We propose a conceptual model where Fungi contribute to controlling the dynamics of phytoplankton populations, as well as the release of organic matter and the transfer of organic carbon through the pelagic trophic web in coastal upwelling ecosystems. PMID:26914416

  2. Ammonia oxidizers are pioneer microorganisms in the colonization of new acidic volcanic soils from South of Chile.

    Science.gov (United States)

    Hernández, Marcela; Dumont, Marc G; Calabi, Marcela; Basualto, Daniel; Conrad, Ralf

    2014-02-01

    Ammonia oxidation, performed by specialized microorganisms belonging to the Bacteria and Archaea, is the first and most limiting step of soil nitrification. Nitrification has not yet been examined in young volcanic soils. The aim of the present work was to evaluate the abundance and diversity of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in acidic volcanic soils (andisols) of different defined ages to determine their relative contribution to nitrification and soil colonization. Soil was collected from three vegetated sites on Llaima Volcano (Chile) recolonized after lava eruptions in 1640, 1751 and 1957. Quantitative polymerase chain reaction, terminal restriction fragment length polymorphism and clone sequence analyses of the amoA gene were performed for the AOA and AOB communities. All soils showed high nitrification potentials, but they were highest in the younger soils. Archaeal amoA genes outnumbered bacterial amoA genes at all sites, and AOA abundances were found to be proportional to the nitrification potentials. Sequencing indicated the presence of AOA related to Nitrososphaera and Nitrosotalea, and AOB related primarily to Nitrosospira and sporadically to Nitrosomonas. The study showed that both AOA and AOB are early colonizers of andisols, but that AOA outnumber AOB and play an important role in nitrification. PMID:24596264

  3. Biological relationship between Central and South American Chibchan speaking populations: evidence from mtDNA.

    Science.gov (United States)

    Melton, Phillip E; Briceño, I; Gómez, A; Devor, E J; Bernal, J E; Crawford, M H

    2007-05-01

    We examined mitochondrial DNA (mtDNA) haplogroup and haplotype diversity in 188 individuals from three Chibchan (Kogi, Arsario, and Ijka) populations and one Arawak (Wayuú) group from northeast Colombia to determine the biological relationship between lower Central American and northern South American Chibchan speakers. mtDNA haplogroups were obtained for all individuals and mtDNA HVS-I sequence data were obtained for 110 samples. Resulting sequence data were compared to 16 other Caribbean, South, and Central American populations using diversity measures, neutrality test statistics, sudden and spatial mismatch models, intermatch distributions, phylogenetic networks, and a multidimensional scaling plot. Our results demonstrate the existence of a shared maternal genetic structure between Central American Chibchan, Mayan populations and northern South American Chibchan-speakers. Additionally, these results suggest an expansion of Chibchan-speakers into South America associated with a shift in subsistence strategies because of changing ecological conditions that occurred in the region between 10,000-14,000 years before present. PMID:17340631

  4. Studies on Phylogenetic Relationship of Sheep Population in East and South of Central Asia

    Institute of Scientific and Technical Information of China (English)

    SUN Wei; CHANG Hong; YANG Zhang-ping; GENG Rong-qing; LU Sheng-xia; DU Lei; NI Da-xing; FAN Bao-sheng; Tsunoda K

    2002-01-01

    This paper was based on the Hu sheep in China, after collecting the same data about 9 Asiasheep populations and 5 European sheep (breeds in Japan) populations. It clustered 15 populations in terms ofthe gene frequency of 10 loci and 33 allele in blood enzyme and other protein variations. The result of Hierar-chy Clustering showed that the sheep populations in the East and South of Central Asia could be classified intothree genetic groups: Mongolia sheep, South Asia sheep and European sheep, and the Hu sheep belonged toMongolia sheep.

  5. Estructura comunitaria de diatomeas presentes en los sedimentos superficiales de ocho lagos andinos de Chile central Diatoms community structure in superficial sediments of eight Andean lakes of central Chile

    Directory of Open Access Journals (Sweden)

    INGRID E ALVIAL

    2008-03-01

    Full Text Available En este trabajo se analizó la estructura comunitaria de diatomeas depositadas en los sedimentos superficiales de ocho lagos andinos chilenos ubicados entre los 32°49' y 38°48' S. Se encontró un total de 99 taxa de diatomeas, distribuidos en 48 géneros. Del total de taxa, 74 fueron identificados a nivel de especie siendo todos ellos cosmopolitas a excepción de Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis y Pinnularia acidicola, entre otras, que están descritos solo para el Hemisferio Sur. Por otro lado, las muestras analizadas presentaron distinta composición florística de diatomeas. De esta manera, en los ensambles diatomológicos depositados en los sedimentos de las lagunas de altura Ocho, Huifa, Ensueño y Negra ubicadas sobre los 2.860 m del nivel del mar, abundaron especies bentónicas, típicas de aguas oligotróficas y acidas como Achnanthidium exiguum, Achnanthidium minutissimum, Encyonema minutum, Pinnularia acidicola y Planothidium lanceolatum. En los ensambles diatomológicos de los lagos Galletué, Icalma y Laja, ubicados bajo los 1.360 m del nivel del mar, abundaron diatomeas planctónicas, características de aguas alcalinas y mesotróficas como Asterionella formosa, Aulacoseira distans, Aulacoseira granulata, Cyclotella stelligera y Rhopalodia gibbaIn this research the taxonomic structure of diatoms in sediments of high mountain lakes was studied. These lakes are located in Chile between 32°49' and 38°48' S in the Andean Cordillera. A total of 99 diatom taxa distributed in 48 genera were identified and all this taxa are cosmopolitan excepting a Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis and Pinnularia acidicola, which are know only for the Southern Hemisphere. The assemblages of diatoms were different in the studied lakes. So the high mountain lakes Ocho, Huifa, Ensueño and Negra, dominated benthic diatoms which are typical of oligotrophic and acid waters as Achnanthidium

  6. Palaeoindian occupation of the Atacama Desert, northern Chile

    Science.gov (United States)

    Grosjean, Martin; Núñez, Lautaro; Cartajena, Isabel

    2005-10-01

    Palaeoindian occupation of the Atacama Desert in northern Chile has been found between 12 600 and 10 200 cal. yr BP. The new site at Salar Punta Negra (24°28S/60°53W/2976 m) includes about 1000 classifiable, mostly unifacial artefacts and, uniquely, three different diagnostic types of early projectile points. Two of the Lateglacial/early Holocene projectile types have wide distribution and are known from different geographical areas in South America: the Palaeoindian Fell fish-tail point mainly from the southern cone of South America, and the triangular Tuina points typical of the Puna of the south-central Andes in northern Chile and northwestern Argentina. In addition, we found a third type, a stemmed point typical for the Salar Punta Negra. Filling a large geographical gap of Fell occupation, the site at Salar Punta Negra provides evidence for generally much higher mobility and diversity of early cultures, and supports an Andean-Pacific route for early human exploration of South America to the south through the desert at intermediate altitudes. Contemporaneous high-amplitude climatic changes were fundamental preconditions to provide adequate environments and habitats, and to make Palaeoindian hunting-gathering occupation possible in the Atacama Desert.

  7. Can We Mitigate Climate Extremes using Managed Aquifer Recharge: Case Studies California Central Valley and South-Central Arizona, USA

    Science.gov (United States)

    Scanlon, B. R.; Reedy, R. C.; Faunt, C. C.; Pool, D. R.; Uhlman, K.

    2015-12-01

    Frequent long-term droughts interspersed with intense floods in the southwestern U.S. underscore the need to store more water to manage these climate extremes. Here we show how managed aquifer recharge can enhance drought resilience in the southwestern U.S. with ~ 70% of California under extreme drought and 75% of Arizona under moderate drought. Data on water sources, transportation, and users were compiled for managed aquifer recharge systems in the Central Valley and south-central Arizona. Groundwater depletion of 115 to 145 km3 in the 1900s created large subsurface reservoirs in thick alluvial basins in these regions. Large canals and aqueducts up to several 100 km long allow water to be imported from reservoirs, mostly in more humid regions. Imported water is either used instead of groundwater or is applied in surface spreading basins primarily during wet periods (≤1.3 km3/yr Central Valley, ≤0.7 km3/yr Arizona) and is extracted during droughts. The dominant water users include irrigators and municipalities both within and outside the managed aquifer recharge systems. Groundwater modeling indicates that recharge basins significantly increase groundwater storage in the Central Valley. Managed aquifer recharge systems significantly enhance drought resilience and increase sustainability of water resources in semiarid regions, complementing surface water reservoirs and conjunctive surface water/groundwater use by providing longer term storage.

  8. Fecal Contamination of Groundwater in a Small Rural Dryland Watershed in Central Chile Contaminación Fecal en Agua Subterránea en una Pequeña Cuenca de Secano Rural en Chile Central

    Directory of Open Access Journals (Sweden)

    Mariela Valenzuela

    2009-06-01

    Full Text Available Research on microbiological groundwater quality was conducted in Chile in a rural watershed that has almost no other water source. Forty-two wells were randomly selected and levels of indicator bacteria - total coliforms (TC, fecal coliforms (FC, and fecal streptococci (FS - were repeatedly measured during the four seasons of 2005. The aim of this study was to characterize microbiological groundwater quality, relate indicator levels to certain watershed features and management characteristics which are likely to affect water quality. The dynamics of seasonal temporal contamination was determined with statistical analyses of indicator organism concentrations. Nonparametric tests were used to analyze relationships between bacterial indicators in well water and other variables. TC, FC, and FS were found in all samples indicating the wells had been contaminated with human and animal fecal material. The frequency distribution of microorganisms fitted a logistic distribution. The concentrations appeared to be temporal and levels varied between seasons with higher concentrations in winter. The cause of contamination could be linked to the easy access of domestic animals to the wells and to the permeable well casing material. Local precipitation runoff directly influenced the bacterial concentrations found in the wells.Se realizó una investigación de la calidad microbiológica de las aguas subterráneas en una cuenca rural chilena. En esta cuenca prácticamente no había otra fuente de agua disponible. En 42 pozos seleccionados al azar, se midieron niveles de bacterias indicadoras en cuatro temporadas distintas durante el año 2005. Las bacterias incluyeron coliformes totales (TC, coliformes fecales (FC y Estreptococos fecales (FS. El objetivo fue caracterizar la calidad microbiológica del agua subterránea y relacionar los indicadores con ciertas propiedades y el manejo de la cuenca que pueden afectar la calidad del agua. La dinámica temporal de la

  9. Temperature changes derived from phenological and natural evidence in South Central China from 1850 to 2008

    Science.gov (United States)

    Zheng, J.; Hua, Z.; Liu, Y.; Hao, Z.

    2015-11-01

    Annual temperature anomalies in South Central China from 1850 to 2008 are reconstructed by synthesizing three types of proxies: spring phenodates of plants recorded in historical personal diaries and observations, snowfall days extracted from historical archives and observed at meteorological stations, and five tree-ring width chronologies. Instrumental observation data and the leave-one-out method are used for calibration and validation. The results show that the temperature series in South Central China exhibits interannual and decadal fluctuations since 1850. The first three cold decades were the 1860s, 1890s, and 1950s, while 1893 was very likely the coldest year. Except for the three warm decades that occurred around 1850, 1870, and 1960, along with the 1920s to the 1940s, the recent warm decades of the 1990s and 2000s represent unprecedented warming since 1850.

  10. Positive interactions between alpine plant species and the nurse cushion plant Laretia acaulis do not increase with elevation in the Andes of central Chile.

    Science.gov (United States)

    Cavieres, Lohengrin A; Badano, Ernesto I; Sierra-Almeida, Angela; Gómez-González, Susana; Molina-Montenegro, Marco A

    2006-01-01

    In alpine habitats, positive interactions among plants tend to increase with elevation as a result of altitudinal increase in environmental harshness. However, in mountains located in arid zones, lower elevations are also stressful because of scarce availability of water, suggesting that positive interactions may not necessarily increase with elevation. Here we analysed the spatial association of plant species with the nurse cushion plant Laretia acaulis at two contrasting elevations, and monitored the survival of seedlings of two species experimentally planted within and outside cushions in the semiarid Andes of central Chile. Positive spatial associations with cushions were more frequent at lower elevations. Species growing at the two elevations changed the nature of their association with cushions from neutral or negative at higher elevations to positive at lower elevations. Survival of seedlings was higher within cushions, particularly at lower elevations. The increased facilitation by cushions at lower elevations seems to be related to provision of moisture. This result suggests that cushion plants play a critical role in structuring alpine plant communities at lower elevations, and that climatic changes in rainfall could be very relevant for persistence of plant communities. PMID:16390419

  11. Application of stable isotopes to evaluate groundwater recharge of a coastal aquifer in North-Central Chile and its role in vegetation dynamics

    International Nuclear Information System (INIS)

    The understanding of the water sources for plant growth is one of the key elements to evaluate the present and long term primary productivity in arid ecosystems. We use stable isotope tools to evaluate the recharge mechanisms in a coastal aquifer located in the arid zone of north-central Chile. The main water sources in the study area, fog, rain and groundwater, were isotopically characterized over a decade. The isotope data confirmed that fog does not play any role in groundwater recharge. The water table and isotope data showed that during low water conditions (dry periods), the aquifer is maintained primarily by water recharged in the higher part of the Romeral basin. During high water table conditions (wet periods), recharge associated with local precipitation becomes a significant source of groundwater recharge. The aquifer responded very fast to rains with amounts over the average level for precipitation (like El Nino conditions), while no recharge was detected with precipitation events lower than the average value for precipitation. The recharge pattern can also influence the behavior of plants characterized by a dimorphic root systems than can perform hydraulic redistribution. Part of the fast recharge of the aquifer could be related to this water redistribution. (author)

  12. Characterization of Trypanosoma rangeli Strains Isolated in Central and South America: an Overview

    OpenAIRE

    1999-01-01

    Trypanosoma rangeli is a hemoflagelate parasite that infects domestic and sylvatic animals, as well as man, in Central and South America. T. rangeli has an overlapping distribution with T. cruzi, the etiological agent of Chagas disease, sharing several animal reservoirs and triatomine vectors. We have isolated T. rangeli strains in the State of Santa Catarina, in southern Brazil, which dramatically increased the distribution area of this parasite. This brief review summarizes several studies ...

  13. Abundance and dynamics of anopheline larvae in a highland malarious area of south-central Ethiopia

    OpenAIRE

    Animut Abebe; Gebre-Michael Teshome; Balkew Meshesha; Lindtjørn Bernt

    2012-01-01

    Abstract Background Malaria is a public health problem in Ethiopia, and increasingly so in highland areas, possibly because of global warming. This study describes the distribution, breeding habitat and monthly dynamics of anopheline larvae in Butajira, a highland area in south-central Ethiopia. Methods A study of the abundance and dynamics of Anopheles larvae was undertaken at different sites and altitudes in Butajira from July 2008 to June 2010. The sites included Hobe (1817 m.a.s.l), Diram...

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

    OpenAIRE

    Farrukh, Affifa; John Francis MAYBERRY

    2015-01-01

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

  15. Noise and Performance: Research in Central, Eastern and South-Eastern Europe and Newly Independent States

    OpenAIRE

    Goran Belojevic

    2013-01-01

    Researches on noise and performance in central and Eastern Europe and South-East Europe countries and Newly Independent States have been performed in last 40 years in Bulgaria, Czechoslovakia, Former Yugoslav Republic of Macedonia, Hungary, Lithuania, Poland, Romania, Union of Soviet Socialistic Republics, Russia, Serbia and Yugoslavia, mainly at universities in the capitals. In laboratory studies the effects of noise have been studied on vigilance, visual performance, attention, information ...

  16. Tuberculosis among HIV-positive patients at Butajira Hospital, South-Central Ethiopia

    OpenAIRE

    Seada Mohammed; Tewelde Tesfaye Gebremariam

    2015-01-01

    Background: Tuberculosis (TB) is the leading cause of morbidity and mortality among people living with Human Immunodeficiency Virus (HIV). This study was carried out to determine the prevalence of tuberculosis and its associated factors among HIV-positive patients at Butajira Hospital, South-Central Ethiopia. Methods: A retrospective review of standardized 222 HIV-positive patient records between July 2011 and June 2012 was conducted. A data sheet was used to collect relevant variables. Data...

  17. Moisture Concentration Variation of Silages Produced on Commercial Farms in the South-Central USA

    OpenAIRE

    Han, K. J.; Pitman, W. D.; Chapple, A

    2014-01-01

    Preservation of forage crops as silage offers opportunity to avoid the high risk of rain-damaged hay in the humid south-central USA. Recent developments with baled silage or baleage make silage a less expensive option than typical chopped silage. Silage has been important in the region primarily for dairy production, but baleage has become an option for the more extensive beef cattle industry in the region. Silage samples submitted to the Louisiana State University Agricultural Center Forage ...

  18. Farmers on the move: mobility, access to land and conflict in Central and South Mali

    OpenAIRE

    Nijenhuis, K.

    2013-01-01

    In contrast to their sedentary image, farmers in Central and South Mali are surprisingly mobile. Many have settled in scattered farming hamlets where they are rapidly expanding the areas under agriculture. This study focuses on farmers’ mobility in relation to accessing land in two regions in Mali where farming conditions are very different regarding rainfall, population growth and opportunities for income generation. It is shown that differences in farming conditions in the two regions have ...

  19. Positions, dispositions and practices in education policy in central and south east Europe (research in progress)

    OpenAIRE

    Slavko Gaber; Živa Kos Kecojević

    2012-01-01

    In the article, we present the conceptualisation and selected results of ongoing research dealing with the particular area of top decision making in education in Central and South East Europe. Aiming at a Bourdieuian type of objectification of key agents of decision making in education – ministers – a group of researchers from the region is in the process of interviewing former ministers of education. The interviews should serve as a (frequently omitted) part of the material for a structured ...

  20. The Emergence of Homo sapiens in South Asia: The Central Narmada Valley as Witness

    Directory of Open Access Journals (Sweden)

    Anek R. Sankhyan

    2013-04-01

    Full Text Available :The emergence of anatomically modern Homo sapiens in South Asia is hotly debated due to a great gap in fossil record. A solitary partial cranium from Hathnora dated around 250 Kya is debated and conveniently interpreted as "evolved" Homo erectus or "archaic" Homo sapiens or Homo heidelbergensis or even Homo indet. Cranial fossils of Pre-Toba or post- Toba anatomically modern Homo sapiens are unknown barring the very late 30 Kya modern human remains from Sri Lanka. The present paper reviews the scenario of human evolution in South Asia with special reference to the cranial and recent postcranial fossil findings by the author in association with the archaeological evidences from Central Narmada valley. It is concluded that the Narmada fossils and archaeological findings support the presence of three hominins- two 'archaic' and one 'early modern'. The Mode 2 Acheulian hominin represented by the calvarium and the femur was a 'large-bodied' species akin to Homo heidelbergensis. It appeared first in the Central Narmada valley and was followed by a 'small-bodied' Mode 3 archaic type represented by two clavicles and the 9th rib, provisionally named here as Homo narmadensis. It likely continued and attained anatomical and behavioural modernity in South Asia as attested by the humerus and bone artifacts, and diversified to various short-bodied indigenous populations of South Asia supported by the genomic evidences.

  1. [Demography and fishery of the sea urchin Loxechinus albus (Echinodermata: Echinidae) in south-austral Chile region].

    Science.gov (United States)

    Arana, Patricio M

    2005-12-01

    In the Magellan Region of southern Chile (52 degrees 20'S - 55 degrees 30'S), the edible urchin Loxechinus albus is collected by 1200 artisanal fishermen, of whom 450 are divers. About 360 small fishing boats and 54 transport vessels carry the fresh product to 16 processing plants. Landings of about 27 000 tons were recorded between January and December 1995. Test diameters of urchins harvested monthly were measured for a total of 119 239 specimens, and 36 406 specimens were individually weighed; sex determination was carried out on 2 314 specimens. Field data indicate that the harvest was about 6.6 x 106 dozen urchins (this is a measuring method employed by fishermen in the region), with an extractive effort of 14 753 diver/days. The fisheries yield ranged from an annual minimum of 235 DUDD (dozen urchins per diver/day) to a maximum of 660 DUDD. In overall terms, the lowest average yields were between January and April (415-427 DUDD), and the highest yields between May and December (456-510 DUDD). Mean sizes increased from June to November and decreased from December to June. Size frequency of males and females were polymodal, with the most relevant modes at 72-84 mm in males, and at 79-88 mm in the females. The percentage of individuals below the minimum legal size (70 mm) did not exceed 4.9% for males and 3.6% for females. The size-weight records fit a power model which suggested that this species has a negative allometric growth (b = 2.007). Regarding weight, urchins in the size range from 80.0 to 84.9 mm were those with the maximum contribution to the regional landings. The highest values recorded for the utilized condition factor were: Average Condition Factor (ACF) = May to July, and November; Isometric (or Cubic) Condition Factor (ICF) = July; and Allometric Condition Factor (ACF) = June. Spawning occurred mainly between August and September, and ended by the end of October. Exploitation of this species represents one of the main sources of employment for

  2. Tribal engagement strategy of the South Central Climate Science Center, 2014

    Science.gov (United States)

    Andrews, William J.; Taylor, April; Winton, Kimberly T.

    2014-01-01

    The South Central Climate Science Center was established by the U.S. Department of the Interior in 2012 to increase understanding of climate change and coordinate an effective response to climate-change effects on Native American tribes and natural and cultural resources that the Department manages. The eight regional Climate Science Centers of the U.S. Department of the Interior work closely with natural-resource management agencies, university researchers, and others such as tribes and private landowners on climate-change issues. The relatively large number of Native Americans in the south central United States and their special knowledge of changing ecosystems make working with tribes and tribal members on climate-change issues particularly important in this part of the Nation. This circular describes priorities of the South Central Climate Science Center and provides information about resources available from Climate Science Centers and partner agencies regarding climate change. The circular also describes how this Climate Science Center, tribes and tribal members, and others can collaborate to minimize potential harmful effects of climate change on human society and our surrounding ecosystems.

  3. Patrón de asentamiento durante el periodo Alfarero en la cuenca de Santiago, Chile Central: Una mirada a la escala local Settlement pattern during the early Ceramic period in the Santiago basin, Central Chile: A view at the local level

    Directory of Open Access Journals (Sweden)

    Luis Cornejo

    2012-11-01

    Full Text Available Se presentan y discuten la metodología y los resultados de prospecciones superficiales de alta intensidad realizadas en el extremo meridional de la cuenca de Santiago, poniendo énfasis en una escala de análisis hasta ahora no considerada en la arqueología de Chile Central, que es el estudio sistemático de la localidad. Los resultados muestran que el patrón de asentamiento denota una alta concentración de ocupaciones domésticas del periodo Alfarero temprano, continuadas más tardíamente pero con menor intensidad. Estas ocupaciones resultan estar vinculadas a la disponibilidad en esta localidad de recursos de aguas superficiales y reflejarían una forma de ocupar el espacio definida por unidades domésticas dispersas que en sus cercanías tendrían a otras unidades sociales no necesariamente vinculadas socialmente.This paper presents the methodology and results of intensive surface surveys carried out in the southern Santiago Basin, focused on the locality, a scale of analysis not previously undertaken in archeological studies of Central Chile. The settlement pattern point out to a high concentration of Early Ceramic Period domestic occupations, followed by less intense occupations during the Late Ceramic Period. These occupations were linked to the availability in this locality of surface water resources and reflect a way of occupying space defined by scattered domestic units , in whose vicinity were other domestic units, although not necessarily connected socially.

  4. Deformación frágil de los depósitos neógenos de la cuenca de Navidad (Cordillera de la Costa, 34°S, Chile central Brittle deformation of the Neogene deposits of the Navidad Basin (Coastal Cordillera, 34°S, central Chile

    Directory of Open Access Journals (Sweden)

    Alain Lavenu

    2005-07-01

    Full Text Available En la cuenca neógena de Navidad, situada en la Cordillera de la Costa de Chile central (~34°S, se identificaron una serie de deformaciones frágiles que fueron generadas durante el Mioceno Tardío y el Plioceno. A partir del análisis numérico de planos de microfallas y sus estrías, se determinaron las direcciones principales de los esfuerzos producidos por diversos eventos tectónicos extensionales y compresivos. Los resultados obtenidos en la cuenca de Navidad permiten concluir que durante el Mioceno Tardío-Plioceno Temprano se produjo una extensión con dirección desconocida. Posteriormente, una deformación extensional, de dirección aproximada este-oeste, afecta a esta zona durante todo el Plioceno. Durante esta época se produce un corto pulso tectónico compresivo de dirección este oeste. A pesar de este evento compresivo la cuenca marina de Navidad se desarrolló esencialmente en un ambiente tectónico extensional durante todo el NeógenoIn the Neogene Navidad Basin, located in the Coastal Range of central Chile (34°S, a series of brittle deformations generated during the Late Miocene and Pliocene, were observed. Based on the numerical analysis of microfault planes and their slickensides, the main stress directions, caused by various extensional and compressive tectonic events, were determined. Results obtained in the Navidad Basin indicate that an extension of unknown direction occurred during the Late Miocene-Early Pliocene. Thereafter, extensional deformation orientated approximately east-west, affected this zone during the whole of the Pliocene. During this epoch a short east-west compressive pulse occurred. In spite of this compressive event, the marine Navidad Basin developed essentially in an extensional tectonic regime during the entire Neogene

  5. Talla de madurez y época de desove de la reineta (Brama australis Valenciennes, 1836 en la costa central de Chile Maturity size and spawning time of the Pacific pomfret (Brama australis Valenciennes, 1836 in the central coast of Chile

    Directory of Open Access Journals (Sweden)

    Elson Leal

    2003-01-01

    Full Text Available La reineta (Brama australis adquiere cada vez mayor importancia en los desembarques de la pesca artesanal, no obstante, es escasa la información que existe acerca de su biología básica, particularmente sobre su dinámica reproductiva. En este trabajo se determina la época principal de desove de B. australis en la costa central de Chile y la talla de madurez (TM, para lo cual se analizó un total de 1061 individuos capturados frente a Lebu (37º37'S-73º40'W, entre enero y septiembre de 2001. El análisis macroscópico de los ovarios, mostró ejemplares sexualmente maduros durante todo el período de muestreo. El Indice Gonadosomático (IGS presentó fluctuaciones que indican un extenso período de desove, con un máximo invernal (junio-agosto. La TM se calculó a partir del método de longitud del 50% de hembras maduras a los 36,9 cm longitud horquilla (LH, con intervalo de confianza entre 35,3 y 37,8 cm y en 39 cm LH mediante el método del Incremento Relativo del IGS (IR.IGS. Debido a que las capturas ocurrieron principalmente en ejemplares sobre 39 cm LH, la flota estaría extrayendo mayoritariamente peces madurosLandings of Pacific pomfret (Brama australis is acquiring an increasing importance to the Chilean artisanal fishery. However, lack of information regarding its basic biology, in particular, reproductive dynamics, still persists. In this work we determine the spawning season of B. australis in the central coast of Chile and the length of maturity (LM. A total of 1061 individuals captured in the coastal zone of Lebu (37°37'S-73°40'W, Chile, between January and September 2001, were analyzed. Macroscopic analysis of ovaries, showed sexually mature individuals throughout the sampling period. Gonadosomatic Index (IGS showed fluctuations indicative of extensive spawning periods, with a maximum in the austral winter season (June-August. LM of females was estimated with the length at 50% maturity method, in 36.9 cm fork length (LH, with

  6. “Today There Are No Indigenous People” in Chile?: Connecting the Mapuche Struggle to Anti-Neoliberal Mobilizations in South America ¿“Hoy en día no hay pueblos indígenas” en Chile?: Conectando la lucha Mapuche con las movilizaciones anti-neoliberales en Sudamérica

    Directory of Open Access Journals (Sweden)

    Kevin Funk

    2012-01-01

    Full Text Available The books under review all deal with the same fundamental phenomenon: mobilization against neoliberal policies by South American indigenous groups. These works fall into two groups: those that focus on the Mapuche struggle in Chile, and those that consider anti-neoliberal indigenous mobilization in the region more broadly. Just as literature in the former group fails to draw any linkages between the Mapuche and other South American indigenous struggles, the latter body of literature does not engage with Chile as a case worthy of consideration. This essay delineates the arguments made by scholars from both groups and argues that they must be brought into dialogue with one another in order to develop both a more holistic conceptualization of the Mapuche struggle in Chile and a more complete understanding of indigenous mobilization in the region. Further empirical work is needed on how Mapuche mobilization relates to other indigenous, anti-neoliberal mobilizations in South America.Los libros discutidos en este ensayo tratan del mismo problema fundamental: la movilización contra las políticas neoliberales por los grupos indígenas en Sudamérica. Estas obras se dividen en dos grupos: los que se enfocan en la lucha de los Mapuche en Chile, y los que consideran la movilización anti-neoliberal de los indígenas más ampliamente. Tal como la literatura en el primer grupo no vincula la lucha Mapuche con otras luchas indígenas en Sudamérica, los del segundo grupo no contemplan el caso chileno. Este ensayo delinea los argumentos hechos por ambos grupos, y sostiene que tiene que haber un diálogo entre sí para poder desarrollar una conceptualización más holística de la lucha de los Mapuche en Chile, y una comprensión más completa de la movilización indígena en la región. Se requieren más investigaciones empíricas acerca de cómo la movilización Mapuche se relaciona con otras movilizaciones indígenas y anti-neoliberales en Sudamérica.

  7. Effects of massive wind power integration on short-term water resource management in central Chile - a grid-wide study

    Science.gov (United States)

    Haas, J.; Olivares, M. A.; Palma, R.

    2013-12-01

    In central Chile, water from reservoirs and streams is mainly used for irrigation and power generation. Hydropower reservoirs operation is particularly challenging because: i) decisions at each plant impact the entire power system, and ii) the existence of large storage capacity implies inter-temporal ties. An Independent System Operator (ISO) decides the grid-wide optimal allocation of water for power generation, under irrigation-related constraints. To account for the long-term opportunity cost of water, a future cost function is determined and used in the short term planning. As population growth and green policies demand increasing levels of renewable energy in power systems, deployment of wind farms and solar plants is rising quickly. However, their power output is highly fluctuating on short time scales, affecting the operation of power plants, particularly those fast responding units as hydropower reservoirs. This study addresses these indirect consequences of massive introduction of green energy sources on reservoir operations. Short-term reservoir operation, under different wind penetration scenarios, is simulated using a replica of Chile's ISO's scheduling optimization tools. Furthermore, an ongoing study is exploring the potential to augment the capacity the existing hydro-power plants to better cope with the balancing needs due to a higher wind power share in the system. As reservoir releases determine to a great extent flows at downstream locations, hourly time series of turbined flows for 24-hour periods were computed for selected combinations between new wind farms and increased capacity of existing hydropower plants. These time series are compiled into subdaily hydrologic alteration (SDHA) indexes (Zimmerman et al, 2010). The resulting sample of indexes is then analyzed using duration curves. Results show a clear increase in the SDHA for every reservoir of the system as more fluctuating renewables are integrated into the system. High

  8. Water Erosion Prediction Using the Revised Universal Soil Loss Equation (RUSLE in a GIS Framework, Central Chile Estimación de la Erosión Hídrica Empleando la Ecuación Universal de Pérdida de Suelo Revisada (RUSLE y SIG en Chile Central

    Directory of Open Access Journals (Sweden)

    Carlos A Bonilla

    2010-03-01

    Full Text Available Soil erosion is a growing problem in Central Chile, particularly in coastal dry lands, where it can significantly decrease the productivity of rainfed agriculture and forestry. In this study, the Revised Universal Soil Loss Equation (RUSLE was integrated into a Geographic Information System (GIS, and used to evaluate the effects of different combinations of vegetative cover on soil erosion rates for Santo Domingo County in Central Chile. Implementing RUSLE in the GIS required a complete description of the county’s soils, climate, topography and current land use/land cover. This information was compiled in rasters of 25 x 25 m cells. RUSLE parameter values were assigned to each cell and annual soil loss estimates were generated on a cell by cell basis. Soil losses were estimated for the current and for three alternate scenarios of vegetative cover. Under current conditions, 39.7% of the county is predicted to have low erosion rates ( 1.1 t ha-1 yr-1. The remainder of the surface (10.2% is not subject to erosion. Under the recommended alternate scenario, 89.3% of the county is predicted to have low erosion rates, and no areas are affected by high soil loss, reducing soil erosion to a level that will not affect long term productivity. This paper describes how RUSLE was implemented in the GIS, and the methodology and equations used to evaluate the effects of the land use/land cover changes.La erosión hídrica es un problema creciente en la Zona Central de Chile, especialmente en el Secano Costero, donde reduce la productividad de los suelos agrícolas y forestales. En este trabajo se empleó la Ecuación Universal de Pérdida de Suelo Revisada (RUSLE integrada a un Sistema de Información Geográfica (GIS para evaluar el efecto de distintas combinaciones de cubierta vegetal en las tasas de erosión en la comuna de Santo Domingo, Chile. La implementación de RUSLE en el GIS requirió la caracterización de suelos, clima, relieve y uso actual del

  9. Geomorphic change along a gravel bed river affected by volcanic eruption: Rio Blanco - Volcan Chaiten (South Chile)

    Science.gov (United States)

    Picco, Lorenzo; Ravazzolo, Diego; Ulloa, Hector; Iroumé, Andres; Aristide Lenzi, Mario

    2014-05-01

    Gravel bed rivers are environments shaped by the balance of flow, sediment regimes, large wood (LW) and vegetation. Geomorphic changes are response to fluctuations and changes of runoff and sediment supply involving mutual interactions among these factors. Typically, many natural disasters (i.e. debris flows, floods and forest fires) can affect the river basin dynamics. Explosive volcanic eruptions present, instead, the potential of exerting severe impacts as, for example, filling river valleys or changing river network patterns thanks to massive deposition of tephra and volcanic sediment all over the main channel and over the basin. These consistent impacts can strongly affect both hydrology and sediment transport dynamics, all over the river system, producing huge geomorphic changes. During the last years there has been a consistent increase in the survey technologies that permit to monitor geomorphic changes and to estimate sediment budgets through repeat topographic surveys. The calculation of differences between subsequent DEMs (difference of DEMs, DoD) is a commonly applied method to analyze and quantify these dynamics. Typically the higher uncertainty values are registered in areas with higher topographic variability and lower point density. This research was conducted along a ~ 2.2 km-long sub-reach of the Blanco River (Southern Chile), a fourth-order stream that presents a mainly rainfall regime with winter peak flows. The May 2008 Chaitén volcanic eruption strongly affected the entire Rio Blanco basin. The entire valley was highly exposed to the pyroclastic and fluvial flows, which affected directly a consistent area of evergreen forests. Extreme runoff from the upper Blanco catchment aggraded the channel and deposited up to several meters of tephra, alluvium, and LW along the entire river system. Aims of this contribution are to define and quantify the short term evolution of the Blanco River after the big eruption event and a subsequent consistent

  10. Using Satellite Tracking and Isotopic Information to Characterize the Impact of South American Sea Lions on Salmonid Aquaculture in Southern Chile.

    Directory of Open Access Journals (Sweden)

    Maritza Sepúlveda

    Full Text Available Apex marine predators alter their foraging behavior in response to spatial and/or seasonal changes in natural prey distribution and abundance. However, few studies have identified the impacts of aquaculture that represents a spatially and temporally predictable and abundant resource on their foraging behavior. Using satellite telemetry and stable isotope analysis we examined the degree of spatial overlap between the South American sea lion (SASL and salmon farms, and quantify the amount of native prey versus farmed salmonids in SASL diets. We instrumented eight SASL individuals with SRDL-GPS tags. Vibrissae, hair and skin samples were collected for δ13C and δ15N analyses from five of the tagged individuals and from four males captured in a haul-out located adjacent to salmon farms. Tracking results showed that almost all the foraging areas of SASL are within close proximity to salmon farms. The most important prey for the individuals analyzed was farmed salmonids, with an estimated median (±SD contribution of 19.7 ± 13.5‰ and 15.3 ± 9.6‰ for hair and skin, respectively. Using vibrissae as a temporal record of diet for each individual, we observed a remarkable switch in diet composition in two SASL, from farmed salmonids to pelagic fishes, which coincided with the decrease of salmon production due to the infectious salmon anemia virus that affected salmon farms in Chile at the end of 2008. Our study demonstrates the usefulness of integrating stable isotope derived dietary data with movement patterns to characterize the impacts of a non-native prey on the foraging ecology of an apex marine predator, providing important applied implications in situations where interactions between aquaculture and wildlife are common.

  11. Estudio hidrogeoquímico en la cuenca altiplánica de Pampa Lirima, Andes Centrales (Chile)

    OpenAIRE

    Achurra, Luciano; Custodio Gimena, Emilio; Aguirre, Igor; Arcos, Rodrigo; Clavero, Jorge

    2011-01-01

    La cuenca de Pampa Lirima se ubica en el límite occidental del Altiplano. Las cumbres y zonas elevadas (4200-5800 msnm) de la cuenca se componen de rocas volcánicas del Oligoceno a Plioceno, donde localmente se desarrollan acuíferos colgados y acuitardos en los sectores afectados por alteración hidrotermal. En la zona central más deprimida (4000-4200 msnm) la cuenca está rellena de depósitos aluviales y pluvioglaciales, que forman un acuífero intergranular libre y artesiano en sectores pun...

  12. Simulation of canal and control-pond operation at the Quivira National Wildlife Refuge, south-central Kansas

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Efficient water management of the Quivira National Wildlife Refuge, located in the Rattlesnake Creek Basin of south-central Kansas, is a complicated task. In a...

  13. Aftershock seismicity and tectonic setting of the 2015 September 16 Mw 8.3 Illapel earthquake, Central Chile

    Science.gov (United States)

    Lange, Dietrich; Geersen, Jacob; Barrientos, Sergio; Moreno, Marcos; Grevemeyer, Ingo; Contreras-Reyes, Eduardo; Kopp, Heidrun

    2016-08-01

    Powerful subduction zone earthquakes rupture thousands of square kilometres along continental margins but at certain locations earthquake rupture terminates. To date, detailed knowledge of the parameters that govern seismic rupture and aftershocks is still incomplete. On 2015 September 16, the Mw 8.3 Illapel earthquake ruptured a 200 km long stretch of the Central Chilean subduction zone, triggering a tsunami and causing significant damage. Here, we analyse the temporal and spatial pattern of the coseismic rupture and aftershocks in relation to the tectonic setting in the earthquake area. Aftershocks cluster around the area of maximum coseismic slip, in particular in lateral and downdip direction. During the first 24 hr after the main shock, aftershocks migrated in both lateral directions with velocities of approximately 2.5 and 5 km hr-1. At the southern rupture boundary, aftershocks cluster around individual subducted seamounts that are related to the downthrusting Juan Fernández Ridge. In the northern part of the rupture area, aftershocks separate into an upper cluster (above 25 km depth) and a lower cluster (below 35 km depth). This dual seismic-aseismic transition in downdip direction is also observed in the interseismic period suggesting that it may represent a persistent feature for the Central Chilean subduction zone.

  14. Deglaciation events in part of the Manchester South 7.5 degrees quadrangle south-central New Hampshire

    Science.gov (United States)

    Stone, Byron D.

    1971-01-01

    The study-area lies in south-central New Hampshire, and is bordered on the west by the Merrimack River, the principal north-south drainage route of central New Hampshire. The classical two tills of New England outcrop in the area. In a unique exposure of the sandy upper till, a loose ablation unit overlies a compact basal unit. Both upper till facies overlie a sheared section of dense, olive-gray lower till. Outwash sequences mapped in the study-area are progressively younger to the north, indicating backwastage of the Wisconsinan ice sheet. Primary structures in proglacial Lake Merrimack sediments include contorted bedding, buckled laminae, and folds. A large slumped section in lake sediments exhibits three distinct deformation zones, characterized by brittle, ductile, and unconsolidated deformation. Cross-cutting relationships establish four fold generations and a deformation sequence in the slumped section. Slip in each fold generation was along nearly parallel slip-lines, as deduced from analyses of fold rotation senses. The primary and slump deformation features contrast sharply with the intense style of deformation of lake beds below till at an apparent ice readvance cut. The deduced drag fold slip-line agrees with till fabric point maxima and dip-slip on one group of thrust faults. A southerly movement of readvancing ice is inferred. The study-area was deglaciated about 13,000 years ago, according to a proposed deglaciation model for New Hampshire. The model is based on Nye's theoretical glacier surface gradient, and evidence for active retreat of the Wisconsinan ice sheet.

  15. Reclaiming our Past: A Critical Race History of Chicana/o Education In South Central Los Angeles, 1930-1949

    OpenAIRE

    Alonso, LLuliana

    2015-01-01

    This dissertation explores the educational experiences of Chicana/os in the first half of the twentieth century using one of the most ethnically diverse communities in the state of California—South Central Los Angeles—as a case study. Driven by the following questions, my research explored: 1) What were the social and economic conditions of the Mexican community of South Central Los Angeles during 1930-1949? 2) What were the dominant discourses about this population during the period understu...

  16. Estabilidad temporal de las infracomunidades de parásitos en la borrachilla Scartichthys viridis (Valenciennes, 1836 (Pisces : Blenniidae en la costa central de Chile Temporal stability in parasite infracommunities of the blenny Scartichthys viridis(Valenciennes, 1836 (Pisces: Blenniidae on the central coast of Chile

    Directory of Open Access Journals (Sweden)

    FREDDY DÍAZ

    2002-12-01

    Full Text Available Se comparan las infracomunidades de parásitos de la borrachilla Scartichthys viridis (Pisces: Blenniidae de tres muestras tomadas en un lapso de 17 meses, entre 1999 y 2001, desde pozas intermareales vecinas a Las Cruces (33°27' S, 71°37' O, Chile central. El objetivo es averiguar si la riqueza, diversidad, abundancia y composición de las infracomunidades de parásitos son persistentes o no en el tiempo ontogenético y cronológico. Se recolectaron 10 taxa parasitarios en cerca del 89 % de los 63 huéspedes examinados, de los cuales ocho eran metazoarios. La búsqueda de protozoos se realizó sólo en los últimos 2 años. El 75 % de los ocho taxa de metazoos ocurrieron en los tres años, uno no estuvo presente en un año, y otro fue encontrado solamente en un año. La mayoría de los huéspedes examinados albergaba protozoos parásitos. La prevalencia de los protozoos Cryptobia sp. fue alta para ambos años, y menor en Trichodina sp. La longitud total de los huéspedes era un predictor relevante de las variaciones en la riqueza, abundancia, diversidad y composición infracomunitaria en el conjunto de los tres años. En cambio, el año de muestreo no lo fue, en particular al comparar entre huéspedes de similar longitud total. Estos resultados son similares a los encontrados en infracomunidades de parásitos de otras especies de peces en Chile, en que hay baja variabilidad en las propiedades agregadas de las infracomunidades en el tiempo cronológico. Se discute acerca de la extensión relativa del tiempo ontogenético en contraste al tiempo cronológico al ser probablemente ambos de importancia en las características de las infracomunidades, y se propone que se explore la medida en la cual estos resultados constituyen un patrón.Parasite infracommunities of the blenny Scartichthys viridis (Pisces: Blenniidae are compared among three samples taken within a 17-month period during three consecutive years (1999-2001, from intertidal pools at

  17. Karyotypic polymorphism and evolution within and between the Liolaemus monticola (Iguanidae "northern 2n = 38-40" chromosome race populations in central Chile Polimorfismo cromosómico y evolución intra e inter poblacional de la raza cromosómica "Norte 2n = 28-40" de Liolaemus monticola (Iguanidae en Chile Central

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    MADELEINE LAMBOROT

    2001-03-01

    Full Text Available Chromosomal genotypes were scored from 359 Liolaemus monticola lizards of the "northern, 2n = 38-40" chromosomal race from 21 locality samples between the Maipo (and one of its tributaries and the Aconcagua (and one of its tributaries ribers, plus a sample from the interracial hybridization zone, and some representative locality samples of the "southern 2n = 34" and the "multiple fission 2n = 42-44" chromosomal races for comparisons. The first seven variable chromosomal pairs were coded as Mendelian genotypes and statistically summarized by several clustering and population genetic algorithms. Spatial and temporal differentiation was assessed by chromosome frequencies, chromosomal diversity and heterozygosity. While no differentiation was found for diversity in the "northern 2n = 38-40" race, chromosomal frequencies and heterozygosity showed significant spatial differentiation that permit distinguishing between the coastal, Andean and transversal mountain range populations. The sample of Cuesta Chacabuco may represent a hybrid zone between the other two range samples. The origin of the chromosomal rearrangements, the population cytogenetics, and the recombination patterns resulting from chromosomal heterozygosity are compared in these chromosomal races, thus expanding the geographical area. These patterns are discussed with respect to the evolution of this complex in Chile and the importance of the riverine barriers in central ChileSe cuantificaron los "genotipos" cromosómicos para 359 lagartijas de 21 muestras poblacionales de la raza "Norte, 2n = 38-40" comprendida entre los ríos: río Maipo y uno de sus afluentes el río Yeso y río Aconcagua (y uno de sus afluentes el río Juncal. Con fines comparativos agregamos una muestra de la zona de hibridación interracial, algunas muestras representativas de la raza "Sur 2n = 34" y una de la raza "múltiples fisiones 2n = 42-44". Los siete primeros pares cromosómicos variables fueron codificados

  18. Fission track thermochronology of Neogene plutons in the Principal Andean Cordillera of central Chile (33-35°S): Implications for tectonic evolution and porphyry Cu-Mo mineralization Termocronología mediante trazas de fision de plutones neógenos en la Cordillera Principal Andina de Chile central (33-35°S): Implicancias para la evolución tectónica y mineralización de pórfidos de Cu-Mo

    OpenAIRE

    Víctor Maksaev; Francisco Munizaga; Marcos Zentilli; Reynaldo Charrier

    2009-01-01

    Apatite fission track data for Miocene plutons of the western slope of the Principal Andean Cordillera in central Chile (33-35°S) define a distinct episode of enhanced crustal cooling through the temperature range of the apatite partial annealing zone (~125-60°C) from about 6 to 3 Ma. This cooling episode is compatible with accelerated exhumation of the plutons at the time of Pliocene compressive tectonism, and mass wasting on the western slope of the Principal Andean Cordillera in central Ch...

  19. Reconstructing glacier mass balances in the Central Andes of Chile and Argentina using local and regional hydro-climatic data

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    M. H. Masiokas

    2015-09-01

    Full Text Available Despite the great number and variety of glaciers in southern South America, in situ glacier mass balance records are extremely scarce and glacier–climate relationships are still poorly understood in this region. Here we use the longest (> 35 years and most complete in situ mass balance record, available for glaciar Echaurren Norte in the Andes at ~34° S, to develop a minimal glacier surface mass balance model that relies on nearby monthly precipitation and air temperature data as forcing. This basic model is able to explain 78 % of the variance in the annual glacier mass balance record over the 1978–2013 calibration period. An attribution assessment indicates that precipitation variability constitutes the most important forcing modulating annual glacier mass balances at this site. A regionally-averaged series of mean annual streamflow records from both sides of the Andes is then used to estimate, through simple linear regression, this glacier's annual mass balance variations since 1909. The reconstruction model captures 68 % of the observed glacier mass balance variability and shows three periods of sustained positive mass balances embedded in an overall negative trend totaling almost −42 m w.eq. over the past 105 years. The three periods of sustained positive mass balances (centered in the 1920s–1930s, in the 1980s and in the first decade of the 21st century coincide with several documented glacier advances in this region. Similar trends observed in other shorter glacier mass balance series suggest the glaciar Echaurren Norte reconstruction is representative of larger-scale conditions and could be useful for more detailed glaciological, hydrological and climatological assessments in this portion of the Andes.

  20. Characterization and comparison of microphytoplankton biomass in the lower reaches of the Biobío River and the adjacent coastal area off Central Chile during autumn-winter conditions Caracterización y comparación de la biomasa microfitoplanctónica en el curso inferior del río Biobío y la zona costera adyacente frente a Chile Central durante condiciones de otoño-invierño

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    Bárbara Léniz

    2012-11-01

    Full Text Available The Biobío River in central Chile is the third largest watershed and second largest river in Chile in terms of discharge volume. Three sampling campaigns were made in the lower reaches of the river and the adjacent coastal ocean to evaluate the influence of the river plume on the physical/chemical conditions and the abundance/biomass of microphytoplankton during autumn-winter conditions. In addition, a preliminary quantification of riverine nutrients, dissolved silica, and phytoplankton carbon flux to the adjacent ocean was also conducted. High nitrate (ño3- and silicic acid (Si(OH4 concentration (>18 and 50 μΜ, respectively was observed in the lower reaches of the river during all field campaigns. Si(OH4 was even high in surface river plume waters. Hydrographic conditions indicate that river plume waters were piled coastward, and they could drove to the south at the Arauco Gulf. In all sampling, highest microphytoplankton biomass (>5000 μgC m-3 was associated to the lower reaches of the river and river plume waters as they were moving southward. During autumn-winter conditions a significant flux of phytoplankton carbon and nutrients to the adjacent coastal ocean also played an important role in the high biological productivity of this coastal upwelling area. These preliminary results evidence the need to conduct large-term studies, which should consider the importance of these allochthoñous carbon sources in global carbon budgets and coastal food-web models.El río Biobío, en la zona central de Chile es la tercera cuenca más grande y segundo río más grande de Chile en térmiños de volumen de descarga de agua dulce. Se realizaron tres campanas de muestreo en el curso inferior del río y la zona costera adyacente para evaluar la influencia de la pluma del río Biobío, en las condiciones físicas/químicas relacionadas con la abundancia/biomasa del microfitoplancton en condiciones de otoño-invierño. Además, se realizó una

  1. Multiscale upwelling forcing cycles and biological response off north-central Chile Ciclos multiescala en el forzamiento de la surgencia y respuesta biológica en el centro-norte de Chile

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    JOSÉ RUTLLANT

    2002-03-01

    Full Text Available The physical forcing of the upwelling along the subtropical west coasts of the continents encompasses a broad range of time scales which shape both phytoplankton biomass (Chl-a and primary productivity (carbon fixation changes over any given time interval. The narrow continental shelf and the steep alongshore orography off north-central Chile provide for a unique combination of year-round, upwelling-favorable winds with quasi-weekly upwelling pulses associated with atmospheric coastal-trapped disturbances (coastal lows. This variability is modulated by intraseasonal oscillations in the depth of the thermo/nutricline, produced by coastal-trapped waves in the ocean, upon which annual (seasons and interannual (ENSO cycles are superimposed. During coastal field experiments off Cruz Grande bay (29º S, carried on in November 1987 and 1988 (opposite extremes of the ENSO cycle, mean changes of the phytoplankton-integrated Chl-a (B and carbon fixation rate (PP from the active to the relaxed phases of the local upwelling forcing cycle (phyto-pattern were characterized. Those data were contrasted against similar ones reported off Punta Lengua de Vaca (Coquimbo, 30º S and off Mejillones peninsula (Antofagasta, 23º S, encompassing different seasons and phases of intraseasonal and interannual (ENSO cycles from 1992 to 1997. A "warm" phyto-pattern was schematically characterized by a significant increase in B and a quasi-steady evolution of PP from the active to the relaxed phases of one complete upwelling event. Conversely, relative small changes in B and a significant increase in PP characterized a "cold" phyto-pattern. It is proposed here that the ENSO "cold/warm" signal may be offset by more than one opposite "thermal" condition (seasonal and/or intraseasonal in defining a "warm" or "cold" phyto-pattern associated with a particular cycle of the local upwelling forcingEl forzamiento físico de la surgencia a lo largo de las costas occidentales de los

  2. Biases in determining the diet of jumbo squid Dosidicus gigas (D' Orbigny 1835) (Cephalopoda: Ommastrephidae) off southern-central Chile (34°S-40°S)

    Science.gov (United States)

    Ibáñez, Christian M.; Arancibia, Hugo; Cubillos, Luis A.

    2008-12-01

    The diet of jumbo squid ( Dosidicus gigas) off southern-central Chile is described to examine potential biases in the determination of their main prey. Specimens were collected from catches using different fishing gear (jigging, trawl and purse-seine), from July 2003 to January 2004, and from December 2005 to October 2006. The stomach contents were analyzed in terms of frequency of occurrence, number, and weight of prey items and the diet composition was analyzed using Detrended Correspondence Analysis. In the industrial purse-seine fleet for jack mackerel ( Trachurus murphyi), the dominant prey of D. gigas was T. murphyi. In the industrial mid-trawl fishery for Patagonian grenadier ( Macruronus magellanicus), the dominant species in the diet of D. gigas was M. magellanicus. Similarly, Chilean hake ( Merluccius gayi) was the main prey in the diet of D. gigas obtained in the industrial trawl fishery for Chilean hake; and, in both artisanal fisheries (purse-seine for small pelagics and jigging), small pelagic fish and D. gigas were the main prey in the stomach contents of D. gigas. Cannibalism in D. gigas varied between different fleets and probably is related to stress behavior during fishing. The Detrended Correspondence Analysis ordination showed that the main prey in the diet of D. gigas is associated with the target species of the respective fishery. Consequently, biases are associated with fishing gear, leading to an overestimate in the occurrence of the target species in the diet. We recommend analyzing samples from jigging taken at the same time and place where the trawl and purse-seine fleets are operating to avoid this problem, and the application of new tools like stable isotope, heavy metal, and fatty acid signature analyses.

  3. Recruitment Dynamics of the Relict Palm, Jubaea chilensis: Intricate and Pervasive Effects of Invasive Herbivores and Nurse Shrubs in Central Chile.

    Science.gov (United States)

    Fleury, Marina; Marcelo, Wara; Vásquez, Rodrigo A; González, Luis Alberto; Bustamante, Ramiro O

    2015-01-01

    Shrubs can have a net positive effect on the recruitment of other species, especially relict species in dry-stressful conditions. We tested the effects of nurse shrubs and herbivory defoliation on performance (survival and growth) of nursery-grown seedlings of the largest living palm, the relict wine palm Jubaea chilensis. During an 18-month period, a total of more than 300 seedlings were exposed to of four possible scenarios produced by independently weakening the effects of nurse shrubs and browsers. The experiment followed a two-way fully factorial design. We found consistent differences in survival between protected and unprotected seedlings (27.5% and 0.7%, respectively), and herbivory had a dramatic and overwhelmingly negative effect on seedling survival. The invasive rabbit (Oryctolagus cuniculus) is clearly creating a critical bottleneck in the regeneration process and might, therefore, partially explain the general lack of natural regeneration of wine palms under natural conditions. Apparently biotic filters mediated by ecological interactions are more relevant in the early stages of recruitment than abiotic, at least in invaded sites of central Chile. Our data reveal that plant-plant facilitation relationship may be modulated by plant-animal interactions, specifically by herbivory, a common and widespread ecological interaction in arid and semi-arid environments whose role has been frequently neglected. Treatments that protect young wine palm seedlings are mandatory to enable the seedlings to attain a height at which shoots are no longer vulnerable to browsing. Such protection is an essential first step toward the conservation and reintroduction of this emblematic and threatened species. PMID:26218100

  4. Cenozoic tholeiitic volcanism in the Colbún area, Linares Precordillera, central Chile (35º35'-36ºS

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    Mario Vergara

    1999-07-01

    Full Text Available RESUMEN Volcanismo toleítico Terciario en el área de Colbún, Precordillera de Linares, Chile central (35º-35º36'S. En la Precordillera de Linares, Chile central (35º5'-36ºS, afloran rocas volcánicas, cuyas edades varían del Eoceno Superior al Mioceno Medio. Sobre la base de criterios estratigráficos y dataciones K-Ar y Ar-Ar, se han diferenciado dos unidades: 1- una Unidad Inferior (Eoceno Superior a Oligoceno Superior, con predominio de rocas volcánicas silíceas en la base y básicas en el nivel superior y 2- una Unidad superior (Mioceno Inferior a Medio, con basaltos afíricos y tobas soldadas riolíticas. Las características geoquímicas de las rocas volcánicas de Colbún, tales como bajos contenidos en K2O, razones MgO/FeO altas, patrones de REE planos, abundancia normalizada con respecto al MORB cercana a la unidad para los elementos Nb a Sc, razones isotópicas iniciales de Sr relativamente bajas (0.703575-0.704028 y relativamente altas de Nd (0.512919-0.513003, son consistentes con una afinidad toleítica y con un grado de contaminación cortical bajo en la evolución de los magmas parentales. Las relaciones isotópicas de Pb y el enriquecimiento en algunos elementos incompatibles, tales como K, Rb, Sr y Ba, sugieren un reciclamiento de material subductado de la placa de Nazca, el cual estuvo acompañado por un adelgazamiento cortical y el desarrollo de estructuras tipo calderas. Isotópicamente, las rocas de Colbún son las más primitivas de los Andes chilenos. Relaciones geoquímicas sugieren que estas rocas se emplazaron en un ambiente geotectónico de trasarco, intracontinental, postorogénico y extensional. Los magmas de Colbún evolucionaron, principalmente, por cristalización fraccional a partir de magmas primarios generados en el manto. Las semejanzas químicas e isotópicas presentadas por estas rocas emplazadas entre el Eoceno Superior y el Mioceno Medio sugieren que las fuentes y procesos, involucrados en su g

  5. Estimating glacier and snowmelt contributions to stream flow in a Central Andes catchment in Chile using natural tracers

    Directory of Open Access Journals (Sweden)

    M. Rodriguez

    2014-07-01

    Full Text Available This paper presents a methodology for hydrograph separation in high elevation watersheds, which aims at identifying individual flow sources such as snow- and ice melt, rainfall and soil water. Daily summer and bi-daily spring water samples from the outlet of the Juncal River were analyzed for all major ions as well as stable water isotopes, δ18O and δ2H. Additionally, various water sources such as rain, springs, snow- and glacial melt were sampled throughout the catchment. A principal component analysis (PCA was performed in order to reduce the dimensionality of the problem. Potential sources were identified in a two-component U space that explains 77% of variability. Hydrograph separation (HS was performed through three models: (i Isotopic model, (ii Mixing–PCA model, and (iii Informative–Bayesian model, with very similar results in each case. At the Juncal River outlet, summer flows were composed by at least 50% of water originating in highly glaciarized headwaters in 2011–2012 (a dry period in the Central Andes. Autumn and winter flows were highly influenced by soil water and affect total annual discharge. Before the high flow season, snow melt accounted for approximately 25% of streamflow, However during summer, when streamflow was highest, snowmelt contribution was minimal, while glacier melt and soil water were the most important sources.

  6. Freezing resistance varies within the growing season and with elevation in high-Andean species of central Chile.

    Science.gov (United States)

    Sierra-Almeida, Angela; Cavieres, Lohengrin A; Bravo, León A

    2009-01-01

    Predicted increases in the length of the growing season as a result of climate change may more frequently expose high-elevation plants to severe frosts. Understanding the ability of these species to resist frosts during the growing season is essential for predicting how species may respond to changes in temperature regimes. Here, we assessed the freezing resistance of 24 species from the central Chilean Andes by determining their low temperature damage (LT(50)), ice nucleation temperature (NT), freezing point (FP) and freezing resistance mechanism (i.e. avoidance or tolerance). The Andean species were found to resist frosts from -8.2 to -19.5 degrees C during the growing season, and freezing tolerance was the most common resistance mechanism. Freezing resistance (LT(50)) varied within the growing season, decreasing towards the end of this period in most of the studied species. However, the FP showed the opposite trend. LT(50) increased with elevation, whilst FP was lower in plants from lower elevations, especially late in the growing season. Andean species have the potential to withstand severe freezing conditions during the growing season, and the aridity of this high-elevation environment seems to play an important role in determining this high freezing resistance. PMID:19210722

  7. Influences of riverine and upwelling waters on the coastal carbonate system off Central Chile and their ocean acidification implications

    Science.gov (United States)

    Vargas, Cristian A.; Contreras, Paulina Y.; Pérez, Claudia A.; Sobarzo, Marcus; Saldías, Gonzalo S.; Salisbury, Joe

    2016-06-01

    A combined data set, combining data from field campaigns and oceanographic cruises, was used to ascertain the influence of both river discharges and upwelling processes, covering spatial and temporal variation in dissolved inorganic carbon (DIC) and aragonite saturation state. This work was conducted in one of the most productive river-influenced upwelling areas in the South Pacific coasts (36°S). Additionally, further work was also conducted to ascertain the contribution of different DIC sources, influencing the dynamics of DIC along the land-ocean range. Six sampling campaigns were conducted across seven stations at the Biobío River basin, covering approximately 200 km. Three research cruises were undertaken simultaneously, covering the adjacent continental shelf, including 12 sampling stations for hydrographic measurements. Additionally, six stations were also sampled for chemical analyses, covering summer, winter, and spring conditions over 2010 and 2011. Our results evidenced that seaward extent of the river plume was more evident during the winter field campaign, when highest riverine DIC fluxes were observed. The carbonate system along the river-ocean continuum was very heterogeneous varying over spatial and temporal scales. High DIC and pCO2 were observed in river areas with larger anthropogenic effects. CO2 supersaturation at the river plume was observed during all campaigns due to the influence of low pH river waters in winter/spring and high-pCO2 upwelling waters in summer. δ13CDIC evidenced that main DIC sources along the river and river plume corresponded to the respiration of terrestrial organic matter. We have linked this natural process to the carbonate saturation on the adjacent river-influenced coastal area, suggesting that Ωaragonite undersaturation in surface/subsurface waters is largely modulated by the influence of both river discharge and coastal upwelling events in this productive coastal area. Conditions of low Ωaragonite might impact

  8. Seismic hazard maps of Mexico, the Caribbean, and Central and South America

    Science.gov (United States)

    Tanner, James G.; Shedlock, Kaye M.

    2004-10-01

    The growth of megacities in seismically active regions around the world often includes the construction of seismically unsafe buildings and infrastructures due to an insufficient knowledge of existing seismic hazard and/or economic constraints. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. We have produced a suite of seismic hazard estimates for Mexico, the Caribbean, and Central and South America. One of the preliminary maps in this suite served as the basis for the Caribbean and Central and South America portion of the Global Seismic Hazard Map (GSHM) published in 1999, which depicted peak ground acceleration (pga) with a 10% chance of exceedance in 50 years for rock sites. Herein we present maps depicting pga and 0.2 and 1.0 s spectral accelerations (SA) with 50%, 10%, and 2% chances of exceedance in 50 years for rock sites. The seismicity catalog used in the generation of these maps adds 3 more years of data to those used to calculate the GSH Map. Different attenuation functions (consistent with those used to calculate the U.S. and Canadian maps) were used as well. These nine maps are designed to assist in global risk mitigation by providing a general seismic hazard framework and serving as a resource for any national or regional agency to help focus further detailed studies required for regional/local needs. The largest seismic hazard values in Mexico, the Caribbean, and Central and South America generally occur in areas that have been, or are likely to be, the sites of the largest plate boundary earthquakes. High hazard values occur in areas where shallow-to-intermediate seismicity occurs frequently.

  9. Seismic hazard maps of Mexico, the Caribbean, and Central and South America

    Science.gov (United States)

    Tanner, J.G.; Shedlock, K.M.

    2004-01-01

    The growth of megacities in seismically active regions around the world often includes the construction of seismically unsafe buildings and infrastructures due to an insufficient knowledge of existing seismic hazard and/or economic constraints. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. We have produced a suite of seismic hazard estimates for Mexico, the Caribbean, and Central and South America. One of the preliminary maps in this suite served as the basis for the Caribbean and Central and South America portion of the Global Seismic Hazard Map (GSHM) published in 1999, which depicted peak ground acceleration (pga) with a 10% chance of exceedance in 50 years for rock sites. Herein we present maps depicting pga and 0.2 and 1.0 s spectral accelerations (SA) with 50%, 10%, and 2% chances of exceedance in 50 years for rock sites. The seismicity catalog used in the generation of these maps adds 3 more years of data to those used to calculate the GSH Map. Different attenuation functions (consistent with those used to calculate the U.S. and Canadian maps) were used as well. These nine maps are designed to assist in global risk mitigation by providing a general seismic hazard framework and serving as a resource for any national or regional agency to help focus further detailed studies required for regional/local needs. The largest seismic hazard values in Mexico, the Caribbean, and Central and South America generally occur in areas that have been, or are likely to be, the sites of the largest plate boundary earthquakes. High hazard values occur in areas where shallow-to-intermediate seismicity occurs frequently. ?? 2004 Elsevier B.V. All rights reserved.

  10. Energy Use and Energy Efficiency in Selected Arable Farms in Central and South Eastern Europe

    OpenAIRE

    Gerhard Moitzi; Milan Martinov; Ladislav Nozdrovicky; Alexandru Naghiu; Andreas Gronauer

    2014-01-01

    The main objective of the project “Mechanization and Energy use in selected arable farms in Central and South Eastern Europe (CASEE)” was to analyse energy characteristics of arable farming in Slovak Republic, Romania, Serbia and Austria, to compare results and identify possibilities of its improvements. The large scale farms are: the university farm of the Slovak University of Agriculture (SK) with 1.112 ha arable land, a cooperative farm in Risnovice (SK) with an arable land of 1.266 ha, ...

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

    Science.gov (United States)

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

    2006-01-01

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

  12. Hydrogeology of the Hanford Site in South-Central Washington State

    International Nuclear Information System (INIS)

    The Hanford Site is situated within the Pasco Basin of south-central Washington and occupies an area of approximately 1450 Km2. The Columbia River flows through the northern edge of the Site and forms part of the eastern boundary. Activities over the past 45 years at the Hanford Site include the siting of nuclear reactors, characterization activities for the Basalt Waste Isolation Project (BWIP), and waste management activities. The purpose of this paper is to discuss the hydrogeology of the Hanford Site and the general extent of contamination due to past activities at the Site. 12 refs., 6 figs

  13. Using fecal profiles of bile acids to assess habitat use by threatened carnivores in the Maulino forest of central Chile Empleo del perfil de ácidos biliares fecales para evaluar uso del hábitat por carnívoros amenazados en el bosque maulino de Chile central

    Directory of Open Access Journals (Sweden)

    CARLA GUERRERO

    2006-03-01

    Full Text Available The distribution and habitat use by carnivores can be assessed by studying their tracks or feces. If these methods are to be used confidently, they should not only unequivocally discriminate among species, but should also render the same patterns of spatial distributions. We assessed the fulfillment of these requirements with five carnivores inhabiting the Maulino forest of central Chile: Galictis cuja, Oncifelis guigna, Pseudalopex culpaeus, Pseudalopex griseus, and Puma concolor. Fecal bile acid thin layer chromatographic profiles were assessed, and shown to be species-specific, invariant within samples of a given individual and among individuals of a given species, but consistently different across species. The spatial distribution of feces in mixed stands of native forests and exotic pine plantations in the coastal Maule region of central Chile was compared with the expected distribution according to habitat offer, and also with the expected distribution based on earlier track records. The results revealed that Pseudalopex culpaeus makes extensive use of pine plantations; Oncifelis guigna prefers native forests, and Pseudalopex griseus thrives in pine plantations, native forests, and patches of native forest, in proportion to habitat availability. Results from scat distribution were similar to those obtained by tracks records. Feces and tracks were thus useful indicators of habitat use by carnivores, and could be used complementarily to study species with conservation problemsEl uso del hábitat por carnívoros puede ser examinado a partir de la distribución de sus huellas y fecas. Para que ambas aproximaciones sean usadas en forma segura y complementaria, ellas deberían no solamente discriminar inequívocamente entre especies, sino que también deberían entregar la misma información sobre los patrones de distribución espacial. Analizamos el cumplimiento de estos requisitos con cinco especies de carnívoros en el bosque maulino de Chile

  14. Efecto del reemplazo de la vegetación nativa de ribera sobre la comunidad de macroinvertebrados bentónicos en arroyos de climas templados, Chile central Replacement effect of riparian native vegetation on benthic macroinvertebrates community in temperate climate streams, Central Chile

    Directory of Open Access Journals (Sweden)

    Gabriela Mancilla

    2009-12-01

    Full Text Available El aporte de materia orgánica desde la vegetación ribereña es determinante en la estructura y complejidad de los sistemas fluviales; es identificado como el mayor aporte energético en ríos y una fuente importante de alimento para macroinvertebrados en arroyos de cabecera. No obstante, el paisaje ribereño ha sido altamente degradado por actividades humanas, lo que ha afectado la estructura y composición de las comunidades acuáticas. El presente estudio se desarrolló en Chile central (región del Biobío donde se concentra una intensa actividad forestal con especies exóticas. Se seleccionaron ríos de bajo orden (The organic matter from riparian vegetation is determined by the structure and complexity of streams. It presents a higher energetic input to streams as well as important source of food for macroinvertebrates in head streams. In spite of its importance, riparian landscape has been rapidly degraded by human activity, this affects structure and composition of the aquatic community. The present study was made in Central Chile (Biobio Region which has intensive forest activity with exotic species. Small streams were selected (< 3 order, because they are very particularly sensitive to changes in land use. The sites were grouped identified according to native forest land cover larger than 20% (group 1 and smaller than 20% (group 2. Significant differences (p< 0.05 in Plecoptera abundance (p < 0.05 were found between the two groups. Differences in trophic groups were significant for shredders and predators increased and gathering-collectors decreased their abundance, with native cover smaller than 20%. This showed the dependent on allochthonous material. The vegetation cover and community parameters correlations showed that Diversity (W increased with higher percentage of watershed covered by native vegetation and exotic species mix. Results suggest that a buffer conservation area of native riparian vegetation is necessary in streams

  15. Biomasa en Chile

    OpenAIRE

    Nilsson Cifuentes, Gabriel; Rodríguez Monroy, Carlos

    2012-01-01

    El artículo presenta el desarrollo de la biomasa en Chile, dentro del complejo marco energético existente en el país, el cual, aún no logra potenciar e incentivar el desarrollo de energías renovables y depende fuertemente de los combustibles fósiles, acrecentando el riesgo latente de sufrir una crisis energética, en el mediano plazo, producto de la paulatina incorporación de nuevas centrales generadoras de energías, que satisfagan la creciente demanda energética pronosticada. Este ar...

  16. La fauna de caprélidos (Crustacea: Amphipoda: Caprellidea de la costa de Coquimbo, centro-norte de Chile, con una clave taxonómica para la identificación de las especies The caprellid fauna (Crustacea: Amphipoda: Caprellidea from the coast of Coquimbo, Northern-central Chile, with a taxonomic key for species identification

    Directory of Open Access Journals (Sweden)

    JOSÉ M. GUERRA-GARCÍA

    2001-12-01

    Full Text Available Los caprélidos son comunes y abundantes en muchos hábitats litorales del ambiente marino. Sin embargo este grupo de anfípodos no ha sido muy bien estudiado en la costa chilena. El estudio de los caprélidos se ha visto dificultado por su gran variabilidad morfológica y el hecho de que la literatura así como los especímenes de los museos son difíciles de localizar. El objetivo de este estudio fue entregar las herramientas taxonómicas para la identificación de las especies de crustáceos caprélidos comunes en el centro-norte de la costa de Chile. Se muestrearon distintos hábitats (boyas, bolones intermareales, praderas de algas y fanerógamas marinas y se encontraron seis especies distintas de caprélidos: Caprellina longicollis (Nicolet, 1849, Caprella equilibra Say, 1818, C. scaura Templeton, 1836, C. verrucosa Boeck, 1871; Deutella venenosa Mayer, 1890 y Paracaprella pusilla Mayer, 1890. Caprella scaura, C. verrucosa y D. venenosa fueron muy abundantes sobre las algas, hidrozoos y briozoos asociados a boyas. Caprella equilibra, también presente en boyas, fue más abundante bajo piedras en zonas intermareales rocosas expuestas, donde también se encontraron ejemplares de D. venenosa y de P. pusilla. Caprella scaura también se encontró sobre algas rojas de las playas arenosas, especialmente sobre Gracilaria chilensis y sobre la fanerógama marina Heterozostera tasmanica, donde cohabitó junto a Caprellina longicollis. Paracaprella pusilla constituye una nueva cita para las costas pacíficas sudamericanas, siendo nueva para la fauna de Chile. La especie D. venenosa, que se cita por primera vez después de la descripción original de Mayer en el año 1890, es considerada una especie endémica de la costa central de ChileCaprellids are abundant in many littoral habitats of the marine environment. Nevertheless, this group of amphipods has been scarcely studied along the coast of Chile. The study of the Caprellidea is particularly

  17. Eruption age of permanent mandibular first molars and central incisors in the south Indian population

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    Gupta Rakhi

    2007-01-01

    Full Text Available Objective: The existing eruption schedules for permanent and deciduous dentition are based on studies in the Western population. Since Indians differ from Westerners racially, genetically, and environmentally, these studies fail to provide relevant guidance on the eruption schedule in the Indian population. This study aims at determining the eruption pattern of permanent mandibular molars and central incisors in the south Indian population. Materials and Methods: 10,156 apparently healthy Indian children in the age-group of 6-9 years were examined with mouth mirror and probe under adequate illumination for the status of the eruption of the permanent mandibular first molar and permanent mandibular central incisor. Pearson′s Chi-square test with Yates′ continuity correction was used to calculate the P -value for comparison of proportion between girls and boys. The values obtained in our study were compared with the standard values. The Z-test with continuity correction was used to calculate the P -value. Results: As per our study, the permanent mandibular first molars and central incisors erupted one to two years later compared to the values reported in Westerners. The earlier eruption of the permanent mandibular first molars compared to the permanent mandibular central incisors, as well as the earlier eruption of both the teeth in girls compared to boys, were in accordance with the existing literature. Conclusion: The eruption age reported by us may form a standard reference for eruption age in Indians.

  18. Thickness variation of Simpson group in south-central Oklahoma and its tectonic significance

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Q.T.; Crump, J. (ARCO Oil and Gas Co., Plano, TX (USA))

    1989-08-01

    The Middle Ordovician Simpson Group in the Southern Oklahoma aulacogen is composed of interbedded sandstone, limestone, and shale. Several pulses of subsidence controlled the deposition of these sediments. Simpson Group thickness variations, based on an isopach map and corresponding regional cross sections, define the presence of two distinct depositional basins flanked on their northern sides by a stable cratonic shelf. The anomalous thickness of Simpson sediments within these basins is related to syndepositional subsidence along zones of weakness initiated during the rifting stage of aulacogen development. The larger basin covers the western part of south-central Oklahoma. The northern flank of this basin illustrates a zone of rapid thickening of sediments. The updip portion of the northern flank is the northernmost limit of the Southern Oklahoma aulacogen. The depocenter of the larger basin is positioned in the Ardmore basin. Paleostress studies using calcite twin lamellae along the southeastern portion of the Sulfur fault within the smaller basin reveal an east-west compression followed by north-south compression. Surface folds formed by the east-west compression are highly faulted and overturned, whereas the folds formed by the north-south compression are open, slightly asymmetric, with rounded hinges and limbs. Similar east-west-trending structures in the subsurface could be a favorable target for hydrocarbon exploration. In general, these basins are genetically related but are separated by a large Precambrian basement block (Tishomingo Granite).

  19. The provenance of archaeological obsidian artifacts from Northern Chile determined by source-induced X-ray fluorescence

    International Nuclear Information System (INIS)

    A study of provenance of obsidian artifacts from 'site 25-Las Estacas', Quebrada de Jorquera (Copiapo, Northern Chile) was carried out by means of X-ray fluorescence, using radioactive sources. Obsidian samples from different Chilean geological regions, located in South Central Chile (Laguna del Maule volcanic area, sources of La Coloradas and La Plata), 'Radal Siete Tazas' and the North of Chile (Copiapo Volcano) were analyzed. The analysis was performed using 109Cd and 241Am annular excitation sources and X-ray fluorescence. This allowed the determination of Fe, Cu, Rb, Sr, Y, Zr, and Ba concentrations on samples of ground obsidian from the aforementioned sites. The measured Rb, Sr, and Zr concentrations were used to construct discriminant diagrams, which clearly showed clustering of the samples from the different sources, and the association of the archaeological obsidian sample to the Copiapo Volcano source, which is geographically close to the site. (author)

  20. The genetic relationship between mafic dike swarms and plutonic reservoirs in the mesozoic of central chile (30A degrees-33A degrees 45'S) : insights from AMS and geochemistry

    OpenAIRE

    C. Creixell; M.A. Parada; D. Morata; Roperch, Pierrich; Arriagada, C

    2009-01-01

    Five mafic dike swarms between 30A degrees and 33A degrees 45'S were studied for their geochemical signature and kinematics of magma flow directions by means of AMS data. In the Coastal Range of central Chile (33A degrees-33A degrees 45'S), Middle Jurassic dike swarms (ConcA(3)n and Cartagena dike swarms, CMDS and CrMDS, respectively) and an Early Cretaceous dike swarm (El Tabo Dike Swarm, ETDS) display the presence of dikes of geochemically enriched (high-Ti) and depleted (low-Ti) basaltic c...

  1. Evolución tectónica, paleogeográfica y metalogénica durante el Cenozoico en los Andes de Chile norte y central e implicaciones para las regiones adyacentes de Bolivia y Argentina

    OpenAIRE

    2009-01-01

    La orogenia incaica dio origen a un importante relieve en el Eoceno Medio, el que se concentró en el ámbito del arco magmático precedente, la Cordillera Incaica. Este relieve positivo de orientación NNE se extendió desde el sur de Perú hasta la región central de Chile y separó dos dominios paleogeográficos que tuvieron evoluciones diferentes durante el resto del Cenozoico. El dominio occidental se caracterizó por el predominio de procesos de erosión y sedimentación. En el dominio oriental tam...

  2. Características de manejo y conducta en caballos estabulados en el sur de Chile: Estudio preliminar Husbandry and behaviour characteristics in stabled horses in the south of Chile: A preliminary study

    OpenAIRE

    C. Márquez; Escobar, A.; TA Tadich

    2010-01-01

    La estabulación de los equinos es una forma de manejo cotidiana, principalmente en aquellos destinados a deporte, provocando modificaciones conductuales debido al cambio desde un ambiente natural a uno artificial, pudiendo afectar su bienestar. En Chile, las condiciones en que se mantienen los equinos estabulados en relación a su bienestar no han sido descritas. El objetivo de este estudio fue describir algunas de las condiciones de estabulación de equinos y determinar si éstas son las requer...

  3. Comunidad ectomicorrícica en una cronosecuencia de Pinus radiata (Pinophyta: Pinaceae de la zona de transición climática mediterráneo-templada de Chile central The ectomycorrhizal community in a chronosequence of Pinus radiata (Pinophyta: Pinaceae of the transitional Mediterranean-temperate climatic zone of central Chile

    Directory of Open Access Journals (Sweden)

    YUSSI M PALACIOS

    2012-03-01

    Full Text Available En ecosistemas naturales y plantaciones, las coníferas establecen asociaciones mutualistas con una comunidad diversa de hongos micorrícicos. El estudio de este tema en Sudamérica es aún incipiente, y no existen antecedentes sobre la dinámica temporal de esta comunidad, y menos de sus potenciales causas, a pesar de su importancia para un país forestal como Chile. En el presente trabajo se evaluó la dinámica de la comunidad ectomicorrícica, identificando y cuantificando los hongos formadores de esta asociación en raíces finas de Pinus radiata en plantaciones de 3, 10 y 20 años. Los resultados confirman que la comunidad ectomicorrícica de P. radiata cambia con la edad de los árboles, la cual difiere más bien en el patrón de dominancia que en la riqueza de especies, separándose un primer grupo de árboles de 3 y 10 años de un segundo grupo de 20 años. Un total de once morfotipos de micorrizas fueron diferenciados. Cuatro de ellos, identificados como Hebeloma crustuliniforme, Inocybe sp., Russula sardonia y Pinirhiza spinulosa, fueron los más abundantes (77, 29, 78 y 8 % respectivamente, mientras las otras se encontraron colonizando menos de 100 puntas de raíz (In natural forest ecosystems and plantations, most trees live in mutualistic association with mycorrhizal fungi. Studies of this association in South America are still scarce, especially when referring to the causes of temporal dynamics of this symbiotic community, despite its importance in countries with a thriving forestry industry like Chile. This study evaluates the dynamics of the ectomycorrhizal community of Pinus radiata stands of 3, 10 and 20 years of age, identifying and quantifying the most common fungal colonizers of fine roots in each age class. The results confirm that the mycobiont community changes with host tree age but that age classes differ in dominance patterns rather than in species richness, with the three- and ten-year-old tree cohorts forming a

  4. Hydrochemical and isotopic patterns in a calc-alkaline Cu- and Au-rich arid Andean basin: The Elqui River watershed, North Central Chile

    International Nuclear Information System (INIS)

    Highlights: ► Major ions are provided by rock weathering and NaCl recycling. ► Aridity and cal-alkaline lithology effects abate acid drainage. ► Factors affecting hydrochemistry in mineral rich zone are addressed. ► Stable isotopes confirm the meteoric origin of groundwaters. ► High sulfate contents are explained by widespread sulfide minerals. - Abstract: The geochemistry of surface water and groundwater from the Elqui River basin, North-Central Chile, was studied in spring 2007 and fall 2008 to obtain a general understanding of the factors and mechanisms controlling the water chemistry of steep rivers located in mineral-rich, arid to semi arid zones. Besides its uniform intermediate igneous lithology, this basin is known for acid drainage and high As contents in the El Indio Au–Cu–As district, in its Andean head. Abundant tailings deposits are present in the middle part of the basin, where agricultural activities are important. According to the results, the chemical and isotopic composition of the Elqui basin surface water and groundwater is related to uniform calc-alkaline lithology and the major polluting system of the chemically reactive, but closed El Indio mining district. The resulting compositional imprints in surface and ground-water are, (a) high SO4 levels, reaching about 1000 mg/L in the Toro River water, directly draining the mining area; (b) a major depletion of Fe and pollutant metals in surface water after the confluence of the Toro and La Laguna rivers; (c) similar chemical composition of surface and ground-waters that differ in H and O isotopic composition, reflecting the effect of differential evaporation processes downstream of the Puclaro dam; and (d) seasonal variations of Fe, Mn, Cu and Zn in surface water. In contrast, the groundwater chemistry exhibits moderate seasonal changes, mainly in HCO3- content. In spite of the acid drainage pollution, water quality is adequate for human consumption and irrigation. This is a

  5. Modelling the hydrological response of debris-free and debris-covered glaciers to present climatic conditions in the semiarid Andes of central Chile

    Science.gov (United States)

    Ayala, Alvaro; Pellicciotti, Francesca; MacDonell, Shelley; McPhee, James; Vivero, Sebastián; Campos, Cristián; Egli, Pascal

    2016-04-01

    We investigate the main contributors to runoff of a 62 km2 glacierized catchment in the semiarid Andes of central Chile, where both debris-free and debris-covered glaciers are present, combining an extensive set of field measurements, remote sensing products and an advanced glacio-hydrological model (TOPKAPI-ETH). The catchment contains two debris-free glaciers reaching down to 3900 m asl (Bello and Yeso Glaciers) and one debris-covered avalanche-fed glacier reaching to 3200 m asl (Piramide Glacier). A unique dataset of field measurements collected in the ablation seasons 2013-14 and 2014-15 included four automatic weather stations, manual measurements of snow depth and debris cover thickness, discharge measurements at glaciers outlets, photographic monitoring of surface albedo as well as ablation stakes measurements and snow pits. TOPKAPI-ETH combines physically-oriented parameterizations of snow and ice ablation, gravitational distribution of snow, snow albedo evolution, glacier dynamics, runoff routing and the ablation of debris-covered ice.We obtained the first detailed estimation of mass balance and runoff contribution of debris-covered glaciers in this mountainous region. Results show that while the mass balance of Bello and Yeso Glaciers is mostly controlled by air temperature lapse rates, the mass balance of Piramide Glacier is governed by debris thickness and avalanches. In fact, gravitational distribution by avalanching on wet years plays a key role and modulates the mass balance gradient of all glaciers in the catchment and can turn local mass balance from negative to positive. This is especially the case for Piramide Glacier, which shows large amounts of snow accumulation below the steep walls surrounding its upper area. Despite the thermal insulation effect of the debris cover, the contribution to runoff from debris-free and debris-covered glaciers is similar, mainly due to elevation differences. At the catchment scale, snowmelt represents more than 60

  6. Field survey of the 16 September 2015 Chile tsunami

    Science.gov (United States)

    Lagos, Marcelo; Fritz, Hermann M.

    2016-04-01

    On the evening of 16 September, 2015 a magnitude Mw 8.3 earthquake occurred off the coast of central Chile's Coquimbo region. The ensuing tsunami caused significant inundation and damage in the Coquimbo or 4th region and mostly minor effects in neighbouring 3rd and 5th regions. Fortunately, ancestral knowledge from the past 1922 and 1943 tsunamis in the region along with the catastrophic 2010 Maule and recent 2014 tsunamis, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. There were a few tsunami victims; while a handful of fatalities were associated to earthquake induced building collapses and the physical stress of tsunami evacuation. The international scientist joined the local effort from September 20 to 26, 2015. The international tsunami survey team (ITST) interviewed numerous eyewitnesses and documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns, performance of the navigation infrastructure and impact on the natural environment. The ITST covered a 500 km stretch of coastline from Caleta Chañaral de Aceituno (28.8° S) south of Huasco down to Llolleo near San Antonio (33.6° S). We surveyed more than 40 locations and recorded more than 100 tsunami and runup heights with differential GPS and integrated laser range finders. The tsunami impact peaked at Caleta Totoral near Punta Aldea with both tsunami and runup heights exceeding 10 m as surveyed on September 22 and broadcasted nationwide that evening. Runup exceeded 10 m at a second uninhabited location some 15 km south of Caleta Totoral. A significant variation in tsunami impact was observed along the coastlines of central Chile at local and regional scales. The tsunami occurred in the evening hours limiting the availability of eyewitness video footages. Observations from the 2015 Chile tsunami are compared against the 1922, 1943, 2010 and 2014 Chile tsunamis. The

  7. Characterization of Trypanosoma rangeli Strains Isolated in Central and South America: an Overview

    Directory of Open Access Journals (Sweden)

    Grisard Edmundo C

    1999-01-01

    Full Text Available Trypanosoma rangeli is a hemoflagelate parasite that infects domestic and sylvatic animals, as well as man, in Central and South America. T. rangeli has an overlapping distribution with T. cruzi, the etiological agent of Chagas disease, sharing several animal reservoirs and triatomine vectors. We have isolated T. rangeli strains in the State of Santa Catarina, in southern Brazil, which dramatically increased the distribution area of this parasite. This brief review summarizes several studies comparing T. rangeli strains isolated in Santa Catarina with others isolated in Colombia, Honduras and Venezuela. The different methods used include indirect immunofluorescence and western blot assays, lectin agglutination, isoenzyme electrophoresis and random amplified polymorphic DNA analysis, triatomine susceptibility, in vitro cell infection assays, and mini-exon gene analysis.

  8. Cephalopods and cetaceans as indicators of offshore bioavailability of cadmium off Central South Brazil Bight

    International Nuclear Information System (INIS)

    Regarding Brazilian coast, industrial and urban developments are concentrated along Central South Brazil Bight. Samples from inshore and offshore species from the concerned area were analyzed, comprising 24 cetaceans (9 species) and 32 squids (2 species). Cadmium was determined by GFAAS and our results were in agreement with certified values (DOLT-2, NRCC). Mean cadmium concentration (in μg/g, wet weight) observed in the digestive gland of sexually mature Argentine short-finned squids (Illex argentinus) was 1002.9. To our knowledge this is the highest cadmium level ever reported for a cephalopod. Concerning cetaceans, our results include one of the highest renal cadmium concentrations described for striped dolphins (71.29 μg/g, wet weight). Anthropogenic action, upwelling and cannibalism of Argentine short-finned squid on the studied area are possible reasons for such remarkable cadmium concentrations. - Cd levels in ommastrephid squids from Brazil are the highest ever reported for cephalopods

  9. Cephalopods and cetaceans as indicators of offshore bioavailability of cadmium off Central South Brazil Bight

    Energy Technology Data Exchange (ETDEWEB)

    Dorneles, Paulo Renato [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil) and Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: dorneles@biof.ufrj.br; Lailson-Brito, Jose [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil) and Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: lailson@uerj.br; Aguiar dos Santos, Roberta [Centro de Pesquisa e Gestao de Recursos Pesqueiros do Litoral Sudeste e Sul, IBAMA, 88301-700 Itajai, SC (Brazil)]. E-mail: gibteuthis@yahoo.com.br; Silva da Costa, Paulo Alberto [Laboratorio de Dinamica de Populacoes Marinhas, UNIRIO, 22290-240 Rio de Janeiro, RJ (Brazil)]. E-mail: pauloascosta@uol.com.br; Malm, Olaf [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil)]. E-mail: olaf@biof.ufrj.br; Azevedo, Alexandre Freitas [Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: azevedo.alex@uol.com.br; Machado Torres, Joao Paulo [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil)]. E-mail: jptorres@biof.ufrj.br

    2007-07-15

    Regarding Brazilian coast, industrial and urban developments are concentrated along Central South Brazil Bight. Samples from inshore and offshore species from the concerned area were analyzed, comprising 24 cetaceans (9 species) and 32 squids (2 species). Cadmium was determined by GFAAS and our results were in agreement with certified values (DOLT-2, NRCC). Mean cadmium concentration (in {mu}g/g, wet weight) observed in the digestive gland of sexually mature Argentine short-finned squids (Illex argentinus) was 1002.9. To our knowledge this is the highest cadmium level ever reported for a cephalopod. Concerning cetaceans, our results include one of the highest renal cadmium concentrations described for striped dolphins (71.29 {mu}g/g, wet weight). Anthropogenic action, upwelling and cannibalism of Argentine short-finned squid on the studied area are possible reasons for such remarkable cadmium concentrations. - Cd levels in ommastrephid squids from Brazil are the highest ever reported for cephalopods.

  10. Trend analysis of sediment grain size and sedimentary process in the central South Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the method of trend analysis of sediment grain size, the sediment transport trend of the fine-grained sediments area in the central South Yellow Sea was studied. The results demonstrated that there is a sedimentation center around the point of 123.4°E, 35.1°N, and the sediments outside the center are transported to it. The patterns of sediment transportation and deposition in the Yellow Sea should be controlled by cyclonic circulation (including the Yellow Sea Cold Water Mass) and cold water gyre. The study also showed that the method of trend analysis of sediment grain size has prospective utilization in the fine-grained sediment deposited area on large-scale continental shelf.

  11. Satellite-based detection of volcanic sulphur dioxide from recent eruptions in Central and South America

    Directory of Open Access Journals (Sweden)

    D. Loyola

    2008-01-01

    Full Text Available Volcanic eruptions can emit large amounts of rock fragments and fine particles (ash into the atmosphere, as well as several gases, including sulphur dioxide (SO2. These ejecta and emissions are a major natural hazard, not only to the local population, but also to the infrastructure in the vicinity of volcanoes and to aviation. Here, we describe a methodology to retrieve quantitative information about volcanic SO2 plumes from satellite-borne measurements in the UV/Visible spectral range. The combination of a satellite-based SO2 detection scheme and a state-of-the-art 3D trajectory model enables us to confirm the volcanic origin of trace gas signals and to estimate the plume height and the effective emission height. This is demonstrated by case-studies for four selected volcanic eruptions in South and Central America, using the GOME, SCIAMACHY and GOME-2 instruments.

  12. Noise and Performance: Research in Central, Eastern and South-Eastern Europe and Newly Independent States

    Directory of Open Access Journals (Sweden)

    Goran Belojevic

    2013-01-01

    Full Text Available Researches on noise and performance in central and Eastern Europe and South-East Europe countries and Newly Independent States have been performed in last 40 years in Bulgaria, Czechoslovakia, Former Yugoslav Republic of Macedonia, Hungary, Lithuania, Poland, Romania, Union of Soviet Socialistic Republics, Russia, Serbia and Yugoslavia, mainly at universities in the capitals. In laboratory studies the effects of noise have been studied on vigilance, visual performance, attention, information perception and processing, reaction time, short term memory and spatial reasoning. The field studies focused on the relation between chronic exposure to community noise and children′s behavior and executive functioning (EF and between industrial noise and occupational injuries. These studies were mainly complementary to the studies in Western Europe.

  13. International Uranium Resources Evaluation Project (IUREP) national favourability studies: Chile

    International Nuclear Information System (INIS)

    Chile has an area of 740,760 square kilometers. The capital is Santiago. The country is 4,183 km. long and ranges from 22.5 to about 354 km. in width. Its chief topographic features para]lei each other - the Coastal Range, Andes Mountains and Central Valley. The Coastal Range rises to 2,130 meters in the north, but averages from 610 to 700 meters high generally. The range plunges into the Pacific Ocean far south of Valparaiso and reappears in the southern archipelagic islands. The Andes extend along nearly the entire length of Chile and contain 100 volcanoes. Andean peaks range mostly from 3,000 to 6,700 meters in elevation. In southern Chile the Andes are lower, and contain about a dozen major lakes. The mountains disappear in Chilean Patagonia, but reappear at Cape Horn. The Central Valley lies between the Coastal Range and the Andes, being best defined in the midland region as a 64 to 72 km sloping plain. It is the Chilean heartland with three-quarters of the country's population. Salt basins are found over much of northern Chile in the very arid desert, while the region south of the Gulf of Reloncavi consists of unpopulated islands, fjords, channels and heavily forested mountains. The Strait of Magellan, the Tierra del Fuego archipelago and a flat grassland area make up the extreme southern end of the country. Much of Chile is subject to flash floods, earthquakes, volcanic eruptions, landslides and avalanches. In September 1976 the Comision Chilena de Energia Nuclear (CCEN) was given exclusive rights to negotiate contracts with private companies for the exploration, development and mining of uranium and other radioactive minerals. The new law provides the CCEN with considerable flexibility in the terms of the contracts. Pre-964 owners of uranium deposits may reach agreements with foreign companies to mine the uranium, but since 1964 all uranium has belonged to the state. Uranium produced in the country can only be exported after Chile's needs have been met. The

  14. Watershed Governance in South-Central Texas: Working from the Bottom up

    Science.gov (United States)

    Lopes, V. L.

    2014-12-01

    The purpose of this presentation is to introduce a set of key concepts that can guide the development of ecological governance systems and briefly describe a watershed ecological governance project in south-central Texas. Ecological governance is a form of governance embedding ecological principles and values in all levels of decision making and action, from the personal to the global. The model of ecological governance discussed here incorporates ideas and approaches that are already being put into practice in many watershed governance projects in the US and abroad; it is based on the premise that contemporary governance systems will continue to evolve in this direction, incorporating more and more of the features of ecological governance. The watershed governance project described here was devised to ensure that the long-term ecological integrity of a small urbanazing waterhed in south-central Texas is preserved and that the water quality standards are maintained for present and future generations. The ecological integrity of small spring-fed watersheds in Texas are under serious threat due to rapid urban development dependent on groundwater supplies, continued drilling of personal wells that are exempt from pumping regulation, and lack of adequate legal jurisdiction for managing development in rural and semi-rural areas. The watershed governance project was motivated by a firm belief of local stakeholders that watershed protection is an individual as well as a community responsibility, and the recognition that a balance between growth and protection is essential to maintain watershed integrity. It is concluded that whereas emergent systems of ecological governance struggle to succeed in an institutional context oriented towards the pursuit of self-interest and competition, their acceptance will happen more readily as ecological principles and values diffuses throughout modern society.

  15. How Socio-Economic Conditions Influence Forest Policy Development in Central and South-East Europe

    Science.gov (United States)

    Vuletić, Dijana; Potočić, Nenad; Krajter, Silvija; Seletković, Ivan; Fürst, Christine; Makeschin, Franz; Galić, Zoran; Lorz, Carsten; Matijašič, Dragan; Zupanič, Matjaž; Simončič, Primož; Vacik, Harald

    2010-12-01

    In this article, several findings on socio-economic conditions derived from national reports and a web-based questionnaire are discussed and related to the changing role of forestry and the future forest policy development. A number of Central and South-eastern European countries taking part in a SEE-ERA-NET project ReForMan project ( www.reforman.de ) participated in data acquisition: Austria, Bosnia and Herzegovina, Croatia, Germany, Serbia and Slovenia. The aim of the research was to illustrate the present structure of forestry sector, as well as investigate newly emerging topics in forestry of Central and South-eastern Europe. The results indicated certain patterns in attitudes and perceptions among stakeholders that can be related to socio-economic conditions defined for each country. Clear differences between member and non-member countries exist only in level of implementation of EU legislation. Results showed consensus on main threats to the forests among all countries, but also some country specifics in perceptions of factors influencing forestry, their importance and professional competencies. These results could be additionally explained by influence of historical conditions which shaped development of forest sector in SEE region especially in its organizational dimension as well as in perceived role of forestry expressed through recognition of main forest functions. The influence of European forest policy processes in the region is evident through adaptation of EU legislation and perceived implications of international processes on national levels. Based on this observation, two possible options for future development of the forestry sector can be foreseen: (i) focusing on the productive function of forests and fostering its' sustainable use; or (ii) putting an emphasis on environmental and social issues. In both cases supporting public participation in decision-making processes is recommendable. Another conclusion based on perceived medium to low

  16. Spatial and temporal interactions between livestock and wildlife in South Central Spain assessed by camera traps.

    Science.gov (United States)

    Kukielka, E; Barasona, J A; Cowie, C E; Drewe, J A; Gortazar, C; Cotarelo, I; Vicente, J

    2013-11-01

    The diversification of livestock farms into hunting estates in South Central Spain (SCS) may impede the success of Mycobacterium bovis eradication programmes by facilitating transmission between wildlife and livestock. In this observational study we aimed to provide information of relevance about the nature and frequency of interactions (observed visits to study points) between livestock (cattle and domestic pigs) and wildlife (wild boar and red deer). The study was conducted in an extensive cattle farm in SCS where the land is also used for game hunting. During a period of one year, camera traps (n=16) were placed at a priori risk points for interspecies interactions: water (natural and artificial troughs), food placed on the ground for baiting wildlife, and pasture. To define indirect interspecies interactions, a critical time window for M. bovis to survive in the environment was selected based on the literature. Results suggest that wildlife frequented food and pasture points more often than water points, and that the number of visits increased through the dry season, peaking during the acorn season (October-January) and the deer breeding season (June-July). Direct interactions were rare (n=10), as opposed to indirect interactions (n=8992). Wildlife-followed-by-livestock interactions (n=7714) occurred much more often than livestock-followed-by-wildlife (n=1278) and were frequent at water points (66% water points, 17% food, 17% pasture). Results also suggest that water points are a hotspot for indirect interactions and might therefore be a source of infection at the wildlife-livestock interface in the territory covered, particularly for M. bovis, as it is around water where the bacteria seem to survive the longest. Preventing aggregation and therefore reducing contact rates between domestic and wild animals especially at water points may be valuable for disease control in South Central Spain. PMID:24050782

  17. Prospección del manejo y utilización de efluentes de lecherías en el sur de Chile A survey of dairy effluent management in the south of Chile

    OpenAIRE

    Salazar, F. J.; Dumont, J.C.; M. A. SANTANA; Pain, B.F.; Chadwick, D. R.; Owen, E

    2003-01-01

    RESUMEN Se realizó una encuesta a predios lecheros ubicados en la Décima Región de Chile durante el período 1995-97. Para la colecta de información se confeccionó un cuestionario, el cual permitió recopilar información referente al manejo y utilización de los efluentes de lechería en estos predios. La información fue analizada con la ayuda de una planilla electrónica que permitió relacionar los distintos parámetros encuestados. Además, en cada visita a los predios se colectó una muestra para ...

  18. Chile ushers in new hydro era

    International Nuclear Information System (INIS)

    The planned construction of two hydroelectric power plants at Peuchen and Mampil, will help to meet Chile's growing electricity demand. Securing finance for the project has been straight forward thanks to the optimal hydrological conditions, rivers with a very strong flow providing a large head of water over short distance. Hydropower plays a central role in Chile's generating capacity providing 70% of total energy consumption. Thus, the future of these projects will be highly successful, it is argued. (UK)

  19. 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

    Directory of Open Access Journals (Sweden)

    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

  20. The typical large-scale superposed folds in the central South China: Implications for Mesozoic intracontinental deformation of the South China Block

    Science.gov (United States)

    Shi, Wei; Dong, Shuwen; Zhang, Yueqiao; Huang, Shiqi

    2015-11-01

    The South China Block has experienced polyphase intensive intracontinental deformation in the Mesozoic time. Large-scale superposed folds in central South China document the Mesozoic tectonic events within the South China Block. Here, we present new structural data related to synfolding deformation, coupling with chronological data, to reconstruct the deformation sequence and tectonic regime during crustal shortening. These data indicate that the superposed folds, dominated by a two-stage tectonic compressive regime, experienced two phases of superposed buckle folding, leading to the orthogonal superposition of NE-SW-trending folds onto WNW-ESE-trending folds between the late Middle Jurassic and the earliest Early Cretaceous. Our structural analysis, together with geochronological data for this area, suggests that the South China Block predominately underwent two phases of intracontinental deformation during the Mesozoic. The early phase of tectonism (D1) is characterized by a late Middle Triassic to earliest Early Jurassic NE-SW compression, causing the occurrence of an orogeny-perpendicular shortening accompanying with evident magmatism. This tectonic event was most likely associated with progressive clockwise collision of the South China Block toward the north in the Indosinian event. Subsequent tectonic activity (D2) between the late Middle Jurassic and the earliest Early Cretaceous contributed to a phase of NW-SE contraction that overprinted the early NE-SW shortening in the interior of the South China Block, generating a large-scale NW-convex fold belt and the typical large-scale superposed folds within the central South China Block. The later tectonism was probably driven by the NW-directed subduction of the paleo-Pacific Plate beneath the eastern part of the Asian continent.

  1. La vertebración territorial en regiones de alta especialización: Valle Central de Chile. Alcances para el desarrollo de zonas rezagadas en torno a los recursos naturales

    Directory of Open Access Journals (Sweden)

    ALBERTO GARCÍA-HUIDOBRO

    2010-04-01

    Full Text Available Los procesos de reestructuración económica y la apertura de los mercados han generado múltiples y variadas consecuencias sobre nuestros territorios. Quizás para Chile, como para otros países latinoamericanos, uno de los más importantes procesos a nivel regional es el desarrollo de espacios altamente especializados o regiones-commodities. Distintos trabajos académicos señalan que interiormente, en conjunto con áreas de gran competitividad, se están generando áreas rezagadas o alejadas de los dinamismos económicos. Por lo tanto: ¿ En qué ha derivado su modelo de vertebración territorial y su sistema de centros poblados ? ¿Cuáles son las características de estas áreas rezagadas ? Y por ende, ¿cuáles son los desafíos a los cuales se enfrentan? El Valle Central de Chile es una de estas áreas donde se evidencia dicha especialización. Por tanto, analizaremos la estructura física territorial en las que han derivado estas regiones y el papel que cumplen sus centros poblados en los nuevos escenarios. A partir de la caracterización de su vertebración territorial avanzaremos hacia la definición de sus zonas menos favorecidas, e intentaremos generar algunas hipótesis que respondan a sus desafíos y requerimientos futuros.Economic restructuring processes and market opening have generated multiple and varied consequences in our territories. Perhaps for Chile, as with other Latin American countries, one of the most important processes at the regional level is the development of highly specialized spaces or commodity-regions. Different academic work indicates that within these spaces, as well as areas of high competitiveness, there are also backward areas with limited economic dynamism. Consequently: What has happened to the model of a territorial spine and system of population center? What are the characteristics of these backward areas? In addition, what are the challenges to be faced? Chile's Central Valley is one of the areas

  2. DETECTION OF LOCAL SITE CONDITIONS INFLUENCING EARTHQUAKE SHOCK AND SECONDARY EFFECTS IN THE VALPARAISO AREA IN CENTRAL-CHILE USING REMOTE SENSING AND GIS METHODS

    OpenAIRE

    Barbara Theilen-Willige; Felipe Barrios Burnett

    2011-01-01

    The potential contribution of remote sensing and GIS techniques to earthquake hazard analysis was investigated in Valparaiso in Chile in order to improve the systematic, standardized inventory of those areas that are more susceptible to earthquake ground motions or to earthquake related secondary effects such as landslides, liquefaction, soil amplifications, compaction or even tsunami-waves. Geophysical, topographical, geological data and satellite images were collected, processed, and integr...

  3. Estimación de la biomasa de langostino amarillo (Cervimunida johni, aplicando Modelo Lineal Generalizado a registros de captura por área barridaen la zona central de Chile Estimating yellow squat lobster (Cervimunida johni biomass by applying a generalized linear model to catch records per swept area in central Chile

    Directory of Open Access Journals (Sweden)

    Cristian Canales

    2012-07-01

    Full Text Available La información obtenida en cruceros de evaluación directa de langostino amarillo (Cervimunida johní realizados en la zona central del Chile (32°-38°S entre 1997 y 2009, permitió modelar los cambios en la densidad anual de este recurso mediante Modelo Lineal Generalizado (MLG. El objetivo de este enfoque fue tanto minimizar el efecto de los distintos criterios y diseños de muestreo que han sido empleados en el tiempo, como también determinar los efectos que explican las variaciones en la densidad de este recurso. Lo anterior permitió estimar el valor esperado de la densidad anual para el cálculo de biomasa mediante el método de "área barrida". Los registros lance a lance de captura por unidad de área barrida (CPUA permitieron la identificación y medición de los focos de abundancia, además de caracterizar la distribución y área que ha ocupado el recurso en el tiempo. El MLG identificó como efectos significativos el año, la zona, la profundidad, y las interacciones anuales de primer orden, explicando con ello el 43% de la devianza residual del modelo. Los principales efectos que explican las variaciones de la CPUA son el año y la interacción año-zona. Se determinó que la zona con mayor abundancia promedio corresponde a la delimitada entre 32° y 34°S, de igual manera que en el rango de profundidad menor a 250 m. Dentro del período analizado, se determinó que la población de este recurso incrementó en biomasa de manera sostenida hasta el 2006, principalmente en la zona norte del área de estudio, seguida de una fuerte reducción que al 2009 equivale al 75% respecto del máximo, reflejada en una biomasa de 11.000 ton.Changes in the annual density of the yellow squat lobster (Cervimunida johni were modeled using a generalized linear model (GLM, using information obtained during direct stock assessment cruises carried out in central Chile (32°-38°S between 1997 and 2009. The purpose of this approach was to minimize the

  4. Shoreline changes in Concón and Algarrobo bays, central Chile, using an adjustment model Cambios en la línea litoral de las bahías de Algarrobo y Concón, Chile central, a través de un modelo de ajuste

    Directory of Open Access Journals (Sweden)

    Carolina Martinez

    2007-11-01

    Full Text Available Adjustment models for both Algarrobo and Concón bays, central Chile, are presented herein; the results show a nearly logarithmic spiral shape for the shore. Spatial-temporal variations in the shorelines of both bays were found based on aerial photographs from different years. The results indicate important variations in the relative position of the Concón Bay shoreline between 1945 and 2006, with extreme oscillations (-368 to 123.8 m only occurring in the proximal zone, where the Aconcagua Estuary is located. On the other hand, the spatial-temporal variations in the Algarrobo Bay shoreline between 1967 and 2006 are moderate (131 in the proximal and -73 in the distal zone. Whereas Concón Bay exhibits a stable state of equilibrium for the past 60 years, if the estuary zone is excluded, Algarrobo Bay presents a stable state with a tendency for growth in the proximal zone and retreat in the distal zone. The results are discussed in terms of coastal changes associated with highly urbanized shorelines and applications for coastal area management that are derived from the modelsSe presentan los resultados de la aplicación de un modelo de ajuste para las bahías de Algarrobo y Concón en Chile central, cuya forma se aproxima a una espiral logarítmica. A partir del uso de fotografías aéreas correspondientes a diferentes años, se determinaron las variaciones espacio-temporales de la línea litoral en ambas bahías. Los resultados indican que la bahía de Concón ha presentado importantes variaciones en la posición relativa de su línea litoral para el período 1945 a 2006, únicamente en su zona proximal, lugar en donde se localiza el estuario Aconcagua con oscilaciones extremas entre -368 m y 123,8 m. En la bahía de Algarrobo, las variaciones espacio-temporales de la línea litoral son de magnitud moderada para el período comprendido entre 1967 y 2006, presentando valores extremos de 131 m en la zona proximal y de -73 m en la zona distal

  5. Floristic changes in alpine plant communities induced by the cushion plant Azorella madreporica (Apiaceae in the Andes of central Chile Cambios florísticos en comunidades de plantas alpinas inducidos por la planta en cojín Azorella madrepórica (Apiaceae en los Andes de Chile central

    Directory of Open Access Journals (Sweden)

    CONSTANZA L QUIROZ

    2009-06-01

    Full Text Available It is well known that the number of plant species associated with nurse plants increases with elevation. However, studies conducted so far have largely ignored the effect of nurse plants on other community attributes, such as the species abundances, diversity and evenness. Moreover, changes in these community attributes along environmental gradients have also been seldom examined. The present study evaluates the effect of the cushion plant Azorella madrepórica (Apiaceae on species richness, species abundance, diversity and evenness of vascular plants at two elevations in the Andes of central Chile. Theoretically, the impact of this nurse cushion plant on these community attributes should be grater at a higher elevation. Results showed that the proportion of plant species associated with cushion plants increases with elevation, and the abundance of some species is also greater within cushions than on bare ground. Although the proportion of species growing within cushions increased with elevation, diversity and evenness were higher on bare ground. This is due to some few species that attained very high densities within cushions, generating assemblages highly dominated by some few species. Ordination analyses indicated differences in species assemblages within and outside A. madrepórica at the higher elevation. Therefore, the influence of cushion plants on community structure changes with elevation. Accordingly, we suggest that attributes other than species richness must be included in future studies in order to analyze the impact of nurse species on community structure along environmental gradients.Se sabe que el número de especies asociado a plantas nodrizas aumenta con la altitud. Sin embargo, el efecto de plantas nodrizas sobre otros atributos de las comunidades, como la abundancia de especies, diversidad y equidad, ha sido largamente ignorado. Más aún, cambios en estos atributos en gradientes ambientales han sido pocas veces examinados

  6. The deep structure of south-central Taiwan illuminated by seismic tomography and earthquake hypocenter data

    Science.gov (United States)

    Camanni, Giovanni; Alvarez-Marron, Joaquina; Brown, Dennis; Ayala, Concepcion; Wu, Yih-Min; Hsieh, Hsien-Hsiang

    2016-06-01

    The Taiwan mountain belt is generally thought to develop above a through-going basal thrust confined to within the sedimentary cover of the Eurasian continental margin. Surface geology, magnetotelluric, earthquake hypocenter, and seismic tomography data suggest, however, that crustal levels below this basal thrust are also currently being involved in the deformation. Here, we combine seismic tomography and earthquake hypocenter data to investigate the deformation that is taking place at depth beneath south-central Taiwan. In this paper, we define the basement as any pre-Eocene rifting rocks, and use a P-wave velocity of 5.2 km/s as a reference for the interface between these rocks and their sedimentary cover. We found that beneath the Coastal Plain and the Western Foothills clustering of hypocenters near the basement-cover interface suggests that this interface is acting as a detachment. This detachment is located below the basal thrust proposed from surface geology for this part of the mountain belt. Inherited basement faults appear to determine the geometry of this detachment, and their inversion in the Alishan area result in the development of a basement uplift and a lateral structure in the thrust system above them. However, across the Shuilikeng and the Chaochou faults, earthquake hypocenters define steeply dipping clusters that extend to greater than 20 km depth, above which higher velocity basement rocks are uplifted beneath the Hsuehshan and Central ranges. We interpret these clusters to form a deeply penetrating, east-dipping ramp that joins westward with the detachment at the basement-cover interface. It is not possible to define a basal thrust to the east, beneath the Central Range.

  7. The Donoso copper-rich, tourmaline-bearing breccia pipe in central Chile: petrologic, fluid inclusion and stable isotope evidence for an origin from magmatic fluids

    Science.gov (United States)

    Skewes, M. Alexandra; Holmgren, Carmen; Stern, Charles R.

    2003-01-01

    The copper-rich, tourmaline-bearing Donoso breccia pipe is one among more than 15 different mineralized breccias in the giant (>50 million metric tonnes of copper) Miocene and Pliocene Río Blanco-Los Bronces copper deposit in the high Andes of central Chile. This breccia pipe, bracketed in age between 5.2 and 4.9 Ma, has dimensions of 500 by 700 m at the current surface 3,670 m above sea level. Its roots have yet to be encountered, and it is >300 m in diameter at the depth of the deepest drill holes. The Donoso breccia is, for the most part, monolithic, containing clasts of the equigranular quartz monzonite pluton which hosts the pipe. It is matrix supported, with between 5 and 25% of the total rock volume consisting of breccia-matrix minerals, which include tourmaline, quartz, chalcopyrite, pyrite, specularite, and lesser amounts of bornite and anhydrite. An open pit mine, centered on this breccia pipe, has a current production of 50,000 tonnes of ore per day at an average grade of 1.2% copper, and copper grade in the breccia matrix is significantly higher. Measured δ18O for tourmaline and quartz from the matrix of the Donoso breccia at different levels of the pipe range from +6.9 to +12.0‰, and measured δD in tourmaline ranges from -73 to -95‰. Temperatures of crystallization of these minerals, as determined by the highest homogenization temperatures of highly saline fluid inclusions, range from 400 to >690°C. When corrected for these temperatures, the stable isotope data indicate that fluids from which these breccia-matrix minerals precipitated were magmatic, with δ18O between +5.6 to +9.1‰ and δD between -51 to -80‰. These isotopic data preclude participation of a significant amount of meteoric water in the formation of the Donoso breccia. They support a model in which brecciation is caused by expansion of magmatic fluids exsolved from a cooling pluton, and breccia-matrix minerals, including copper sulfides, precipitated from the same magmatic

  8. Consistent magmatic and magnetic anisotropy data in La Gloria Pluton, central Chile: Implications for the magma flow record in a shallow pluton

    Science.gov (United States)

    Payacan, I.; Gutierrez, F. J.; Bachmann, O.; Parada, M.

    2012-12-01

    The magmatic origin of the anisotropy of magnetic susceptibility (AMS) is examined in comparison with magmatic anisotropy data in a small, shallow, silicic magma reservoir in the upper crust. La Gloria Pluton (LGP) is a 10 Ma granodiorite/quartz monzonite of about 250 km3 located in the southern Andes, central Chile. LGP represents a particularly simple case of a silicic intrusion which was assembled in a few pulses and cooled over a short time interval. Hornblende, biotite and minor magnetite are ubiquitous mafic phases. The AMS tensor indicates that magnetic fabric has an oblate shape (i.e. magnetic foliation is higher than magnetic lineation). Lineations are weak (values up to 1.05), have a N-NW trend with a nearly horizontal dip and represent axisymmetric convection parallel to the main pluton elongation. Foliations are more pronounced (values up to 1.14), having NW trends and dips that vary gradually from vertical at the walls, to horizontal at the center and near the roof of the chamber. We interpret this to represent shear localization near the magma locking point along solidification fronts. Magmatic anisotropy data were obtained by measuring mineral length, width and orientation in the three main planes of the AMS tensor. We define the planes Pmax, Pint, and Pmin as orthogonal to the maximum, intermediate, and minimum axes of the AMS tensor, respectively. Mineral data were collected for plagioclase and amphibole + bitotite independently. For each site, the Bingham distribution with 95% of confidence is used to determine the mean mineral orientation and their angle difference with the AMS axes. Preliminary results indicate that mean crystal orientations are well defined for Pmax and Pint for all analyzed minerals, but Pmin is only well constrained for amphibole + bitotite and poorly constrained for plagioclase. Angle differences generally decrease with magnetic anisotropy but are independent of the size and aspect ratio of the crystals. Mean values of

  9. Relaciones entre la distribución de recursos pelágicos pequeños y la temperatura superficial del mar registrada con satélites NOAA en la zona central de Chile Relationships between the small pelagic resources distribution and the sea surface temperatures recorded by NOAA satellites from Chile central zone

    Directory of Open Access Journals (Sweden)

    Eleuterio Yáñez R

    1996-01-01

    Full Text Available Se realiza un estudio exploratorio para determinar la posibilidad de introducir el uso de imágenes de temperatura superficial del mar (TSM, confeccionadas con datos de satélites NOAA, en las pesquerías de recursos pelágicos pequeños de la zona central de Chile. Se determinan significativas relaciones entre los rendimientos de las especies analizadas y los gradientes térmicos (GRT en forma particular. Estos se asocian a aguas oceánicas en el caso del jurel (Trachurus murphyi, y a surgencias costeras en relación con la anchoveta (Engraulis ringens y sardina común (Clupea bentincki. Se concluye que el uso de imágenes de TSM-NOAA puede jugar un papel importante en la operación de flotas, particularmente de las del tipo de embarcaciones consideradas en el presente trabajo.A survey study was conducted to assess the possibility of introducing the use of sea surface temperatures (SST, obtained from NOAA satellite data, for the small pelagic fisheries resources. Relationships between species yields and thermal gradients (TGR were found significant. Jack mackerel (Trachurus murphyi yields were largely related with a strong thermal gradient next to oceanic waters, while anchovy (Engraulis ringens and common sardine (Clupea bentincki yields were mainly associated to the development of coastal upwelling events. It is concluded that the use of SST-NOAA images can play an important role in fleet operations, particularly in the case ot the type of boats considered in this paper.

  10. Sedimentology, paleoclimatology, and diagenesis of Post-Hercynian continental deposits in the South-Central Pyrenees, Spain

    NARCIS (Netherlands)

    Nagtegaal, Peter J.C.

    1969-01-01

    The first chapter of the post-Hercynian geologic history of the South-Central Pyrenees is recorded in a sequence of fluvial and volcanic deposits which reach a total of added maximum thicknesses of more than 2300 m and date from the Westphalian D up to and including the Lower Triassic. The present s

  11. A comparative study of Taiwan's short-term medical missions to the South Pacific and Central America

    Directory of Open Access Journals (Sweden)

    Chiu Ya-Wen

    2012-12-01

    Full Text Available Abstract Background Taiwan has been dispatching an increasing number of short-term medical missions (STMMs to its allied nations to provide humanitarian health care; however, overall evaluations to help policy makers strengthen the impact of such missions are lacking. Our primary objective is to identify useful strategies by comparing STMMs to the South Pacific and Central America. Methods The data for the evaluation come from two main sources: the official reports of 46 missions to 11 countries in Central America and 25 missions to 8 countries in the South Pacific, and questionnaires completed by health professionals who had participated in the above missions. In Central America, STMMs were staffed by volunteer health professionals from multiple institutions. In the South Pacific, STMMs were staffed by volunteer health professionals from single institutions. Results In comparison to STMMs to Central America, STMMs to the South Pacific accomplished more educational training for local health providers, including providing heath-care knowledge and skills (p Conclusions Health-care services provided by personnel from multiple institutions are as efficient as those from single institutions. Proficiency in the native language and provision of education for local health-care workers are essential for conducting a successful STMM. Our data provide implications for integrating evidence into the deployment of STMMs.

  12. Nurse effect in seedling establishment: facilitation and tolerance to damage in the Andes of central Chile Efecto nodriza en el establecimiento de plántulas: facilitación y tolerancia al daño en los Andes de Chile central

    Directory of Open Access Journals (Sweden)

    IAN S ACUÑA-RODRÍGUEZ

    2006-09-01

    Full Text Available Nurse effects, which occur when one plant species enhances the survival or growth of another plant species, are predicted to be most relevant in stressful environments. These effects are particulary important during seedling establishment due to their vulnerability to both biotic and abiotic factors, such as herbivory and drought. Tolerance to herbivory reflects the degree to which plants are able to regrow and reproduce after damage, and should vary with resource availability. In the high Andes of central Chile, the cushion plant Laretia acaulis (Apiaceae acts as a buffer against environmental stress, enhancing survival of several associated plant species. We hypothesized that tolerance to herbivory of seedlings growing inside the canopy of L. acaulis should be greater than that of seedlings growing outside the cushion plant. We conducted a field experiment to test this hypothesis for two native perennial species in the high Andes of central Chile: Hordeum comosum (Poaceae and Haplopappus anthylloides (Asteraceae. Seedlings of each species were planted inside and outside L. acaulis cushions and half of them received manual damage (50 % foliar tissue removed. Seedlings growing inside the nurse species showed high survival independent of the damage treatment. Whereas position (inside or outside the cushion plant did not affect tolerance of Haplopappus anthylloides, it significantly affected tolerance of Hordeum comosum. Thus, we found similar survival of damaged and control seedlings of H. comosum inside the cushions, but survival of damaged seedlings in the bare ground was lower than that of control seedlings. We verified the occurrence of nurse effects of Laretia acaulis on the establishment of both species, and detected enhancement of tolerance to damage in Hordeum comosum in this stressful habitatSe ha sugerido que el efecto nodriza, el cual se evidencia cuando una especie vegetal incrementa la supervivencia o el crecimiento de otra, es m

  13. Description of the Oocysts of Three New Species of Eimeria (Apicomplexa: Eimeriidae from Iguanid Lizards (Sauria: Iguanidae of Central and South America

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    Daszak P

    1998-01-01

    Full Text Available Three new species of Eimeria are described from iguanid lizards of Central and South America. The oocysts of each species have no micropyles or residua and the sporocysts lack Stieda bodies, but all have a sporocyst residuum. Eimeria sanctaluciae n.sp. was found in the St. Lucia tree lizard, Anolis luciae, collected from the Maria Islands, Lesser Antilles. The oocysts are spherical to subspherical, averaging 17.3 x 16.5 µm, with a single layered colourless wall; about 60% contain polar granules. The sporocysts are ellipsoidal and average 7.7 x 5.5 µm. Eimeria liolaemi n.sp. was recovered from the blue-gold swift, Liolaemus taenius, from Chile. The oocysts are spherical to subspherical, measuring 21 x 20.1 µm with a single-layered colourless wall. The sporocysts are subspherical and average 7.4 x 6.8 µm. Eimeria caesicia n.sp. is described from the Brazilian collared iguanid, Tropidurus torquatus. The oocysts measure 27.4 x 23.7 µm, are spherical to subspherical, with a bilayered wall, the outer surface of which appears pale blue in colour, the thin, inner wall appearing brown, when viewed by direct light under the optical microscope. The sporocysts are subspherical and average 9.4 x 7.2 µm. Unnamed polysporocystid oocysts with dizoic sporocysts are reported from the faeces of the lesser St. Vincent tree lizard, Anolis trinitatis and the possibility of spurious parasitism briefly discussed. In addition, oocysts of an unnamed Isospora sp. with a smooth oocyst wall which closely resembles I. reui were recovered from A. trinitatis.

  14. Forest Typification to Characterize the Structure and Composition of Old-growth Evergreen Forests on Chiloe Island, North Patagonia (Chile)

    OpenAIRE

    Jan R. Bannister; Pablo J. Donoso

    2013-01-01

    The Evergreen forest type develops along the Valdivian and North-Patagonian phytogeographical regions of the south-central part of Chile (38° S–46° S). These evergreen forests have been scarcely studied south of 43° S, where there is still a large area made up of old-growth forests. Silvicultural proposals for the Evergreen forest type have been based on northern Evergreen forests, so that the characterization of the structure and composition of southern Evergreen forests, e.g., their typific...

  15. Abanico East Formation: petrology and geochemistry of volcanic rocks behind the Cenozoic arc front in the Andean Cordillera, central Chile (33°50'S

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    Marcia Muñoz

    2006-01-01

    Full Text Available The stratigraphy, chemistry and age of rocks assigned to the eastern portion of the Abanico Formation exposed along the El Volcán river valley, Principal Cordillera east of Santiago (30º50'S/70º12'-70º5'W, are reported and discussed. This ca. 3,300 m thick succession is mainly composed of basalts, basaltic andesites and volcaniclastic rocks. 40Ar/39Ar radiometric dates on plagioclase from the lava flows yield Oligocene-lower Miocene ages with a maximum age of 34.3 ±0.4 Ma for the lower part and a plateau age of 21.4±1.0 Ma for the upper part of the succession. The lava flows show calc-alkaline affinities and have chemical characteristics that are typical of arc volcanic rocks erupted in an active continental margin. A temporal chemical evolution in the sequence is indicated by upward increases in concentrations of LILE and LREE elements and LaN/YbN ratios. This pattern can be attributed to increasing contributions of fluids derived from the subducted lithosphere with time. A chemical comparison of these rocks with Oligocene-lower Miocene volcanic rocks from the Cerro Abanico and Chacabuco areas on the western border of the Principal Cordillera, east of Santiago, and at the northern end of the Central Depression reveals west to east compositional variations. From west to east these variations include: (1 increasing LILE and LREE concentrations, LaN/YbN ratios and Sr and Nd initial isotopic ratios, and (2 decreasing LILE/HFSE and LREE/HFSE ratios. These pattern can be attributed to a west to east decrease in the contribution of slab derived fluids and increase in the influence of crustal contamination processesLa formación Abanico Este: petrología y geoquímica de las rocas volcánicas detrás del arco Cenozoico en la Cordillera Andina, Chile central (33º50'S. Se presentan los resultados del estudio de la estratigrafía, química y edades de rocas asignadas a la franja oriental de la Formación Abanico expuestas en la ladera sur del R

  16. THE FIELD OF RECENT TECTONIC STRESSES IN CENTRAL AND SOUTH-EASTERN ASIA

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    Yu. L. Rebetsky

    2015-09-01

    Full Text Available  The publication presents results of the study aimed at reconstruction of recent crustal stresses for Central and South-Eastern Asia with application of the method of cataclastic analysis of displacements caused by ruptures, which was proposed by Yu.L. Rebetsky. Two sources of seismic data were referred to: (1 the catalog comprising data from publications covering the period from 1904 to 1992, and (2 the Global Centroid Moment Tensor (CMT Database of earthquake mechanisms (http://earthquake.usgs.gov/eqarchives/sopor, which covers the period from 1978 to 2010. The method of cataclastic analysis in its earliest version was applied in 1996 and 1997 when seismic data from the first catalog were analyzed, and it yielded only parameters of stress ellipsoids; the reconstructions were published in a Russian-Chinese journal (it does not exist now. In this paper, these reconstructions are presented in new graphical formats of GIS. Data from the Global CMT Database were analyzed by the method of cataclastic analysis in the new revision with application of its stages 1 and 2. Based on the calculations, orientations of axes of principal stresses, types of ellipsoids, correlations between spherical and deviatoric components of stress tensors, and reduced stresses were determined. The two sets of reconstructions are compared in this paper. The catalog of earthquake focal mechanisms for the period from 1904 to 1992 consolidated information provided by different authors, and thus focal data for many seismic events were highly inconsistent; therefore, the reliability of reconstructions based on such data seems to be lower than that on the basis the Global CMT Database for the period from 1978 to 2010. Some of the reconstructed stress tensor parameters are mapped. For the areas which data are given in the Global CMT Database and considered as more reliable, mapping is based on stress parameters calculated from such data. For the areas that are not covered by the

  17. Biomarker evidence for increasing aridity in south-central India over the Holocene

    Science.gov (United States)

    Sarkar, S.; Wilkes, H.; Prasad, S.; Brauer, A.; Basavaiah, N.; Strecker, M. R.; Sachse, D.

    2012-12-01

    Summer monsoonal rainfall has played an important role in the development and sustenance of the largely agro-based economy in the Indian subcontinent in the recent past. A better understanding of past variations in monsoonal rainfall can therefore lead to an assessment of its potential impact on early human societies. However, our knowledge of spatiotemporal patterns of past monsoon strength, as inferred from proxy records, is limited due to the lack of high-resolution paleo-hydrological records from continental archives. Here, we reconstruct centennial-scale hydrological variability associated with changes in the intensity of the Indian Summer Monsoon based on a record of lipid biomarker abundances and compound-specific stable isotopic composition of a 10-m-long sediment core from saline-alkaline Lonar Lake, situated in the core 'monsoon zone' of south-central India. We identified three periods of distinct hydrology over the Holocene in south-central India. The period between 10.4 and 6.5 ka BP was characterized by a relatively high abundance of land-plant biomarkers, such as long-chain n-alkanes. The composition of these leaf-wax n-alkanes (weighted average of concentration of different chain-length n-alkanes, expressed as the ACL index) and their negative δ13C (-30‰ to -33 ‰) indicate the dominance of woody C3 vegetation in the catchment, and negative δD (-170‰ to -175‰) values argue for a wet period due to an intensified monsoon. Rapid fluctuations in abundance of both terrestrial and aquatic biomarkers between 6.5 and 4 ka BP indicate an unstable lake ecosystem, culminating in a transition to arid conditions. Higher ACL values and a pronounced shift to more positive δ13C values (up to -22‰) of leaf-wax n-alkanes over this period indicate a change of dominant vegetation to C4 grasses. Along with a 40‰ increase in leaf wax n-alkane δD values, which likely resulted from less rainfall and/or higher plant evapotranspiration, we interpret this period

  18. Frontier areas and exploration techniques. Frontier uranium exploration in the South-Central United States

    International Nuclear Information System (INIS)

    Selected areas of the South-Central United States outside the known U trends of South Texas have a largely untested potential for the occurrence of significant U mineralization. These areas, underlain by Tertiary and older sediments, include parts of Texas, Oklahoma, Arkansas, Louisiana, Mississippi and Alabama. The commonly accepted criteria employed in U exploration are applicable to these frontier areas but special consideration must also be given to the atypical geologic aspects of such areas as they may apply to relatively unique types of U mineralization or to the development of special exploration criteria for common types of roll-front and fault-and dome-related uranium mineralization. The procedures used in evaluating frontier areas should be based on comprehensive evaluations involving: (1) location and analysis of potential source rocks (e.g., intrusive igneous rocks, bentonitic sediments, unique complexes, etc.); (2) definition of regional variations in the potential host sediments (e.g. marginal marine to nonmarine environments of deposition); (3) review of all available radiometric data in Tertiary or older rocks; (4) local groundwater sampling; (5) widely spaced reconnaissance (or stratigraphic) drilling, coring and borehole geophysical logging to define favorable sedimentary facies and to establish the specific lithologic character of the sediments; and (6) detailed petrographic evaluation of all available samples to define the environment of deposition and diagenetic history of ''favorable'' sediments. If procedures produce favorable results, an expanded exploration program is justified. Depths up to 3,000 feet should be anticipated if up-dip information is favorable. Selected areas are discussed that have: (1) favorable source and host rocks;(2) favorable age; (3) favorable regional and local structure; and (4) radiometric characteristics favorable for U mineralization of potentially economic grade and reserves in the areas

  19. Nuevo esquema estratigráfico para los depósitos marinos mio-pliocenos del área de Navidad (33º00'-34º30'S, Chile central New stratigrafic scheme for the Mio-Pliocene marine deposits of the Navidad area (33º00'-34º30'S, central Chile

    Directory of Open Access Journals (Sweden)

    Alfonso Encinas

    2006-07-01

    Full Text Available Varios autores han propuesto diferentes esquemas estratigráficos para los depósitos sedimentarios neógenos marinos que afloran en la zona costera de Chile central entre Valparaíso (~33°00'S y Punta Topocalma (~34°30'S, sin que exista un consenso al respecto. Tampoco existe acuerdo respecto a las correlaciones entre los depósitos que afloran en la parte norte de dicha zona, entre Valparaíso y San Antonio (~33°30'S con aquellos que aparecen en la parte sur, entre San Antonio y Punta Topocalma. Sobre la base de nuevos estudios estratigráficos, sedimentológicos y paleontológicos se propone, de manera formal, un nuevo esquema estratigráfico para estos depósitos. De acuerdo con este nuevo esquema se definen la Formación Navidad (Mioceno Superior-Plioceno Inferior y las formaciones Licancheu, Rapel y La Cueva (Plioceno. Se propone la elevación de las tres primeras unidades (Navidad, Licancheu y Rapel, generalmente consideradas como miembros en clasificaciones anteriores, al rango de formaciones debido a que se encuentran separadas por discontinuidades (paraconformidades de escala regional. En el presente trabajo se definen estas unidades, se revisan los esquemas anteriores y se justifica la proposición de este nuevo esquemaDifferent stratigraphic schemes have been proposed by various authors for the Neogene marine sedimentary deposits cropping out along the central Chilean coast between Valparaíso (~33°00'S and Punta Topocalma (~34°30'S, without any consensus having been reached. Neither does any agreement exist with respect to the correlation between the deposits cropping out in the northern part of this area, between San Antonio (~33°30'S and Valparaíso, and those of the southern part, between San Antonio and Punta Topocalma. Based on new stratigraphic, sedimentologic and paleontologic studies we propose a formal, new stratigraphic classification for this area. According to this scheme we define the Navidad Formation (Upper

  20. Mobile LiDAR Measurement for Aerosol Investigation in South-Central Hebei, China

    Science.gov (United States)

    qin, kai; Wu, Lixin; Zheng, Yunhui; Wong Man, Sing; Wang, Runfeng; Hu, Mingyu; Lang, Hongmei; Wang, Luyao; Bai, Yang; Rao, Lanlan

    2016-04-01

    With the rapid industrialization and urbanization in China during the last decades, the increasing anthropogenic pollutant emissions have significantly caused serious air pollution problems which are adversely influencing public health. Hebei is one of the most air polluted provinces in China. In January 2013, an extremely severe and persistent haze episode with record-breaking PM2.5 outbreak affecting hundreds of millions of people occurred over eastern and northern China. During that haze episode, 7 of the top 10 most polluted cities in China were located in the Hebei Province according to the report of China's Ministry of Environmental Protection. To investigate and the spatial difference and to characterize the vertical distribution of aerosol in different regions of south-central Hebei, mobile measurements were carried out using a mini micro pulse LiDAR system (model: MiniMPL) in March 2014. The mobile LiDAR kit consisting of a MiniMPL, a vibration reduction mount, a power inverter, a Windows surface tablet and a GPS receiver were mounted in a car watching though the sunroof opening. For comparison, a fixed measurement using a traditional micro pulse LiDAR system (model: MPL-4B) was conducted simultaneously in Shijiazhuang, the capital of Hebei Province. The equipped car was driven from downtown Shijiazhuang by way of suburban and rural area to downtown Cangzhou, Handan, and Baoding respectively at almost stable speed around 100Km per hour along different routes which counted in total more than 1000Km. The results can be summarized as: 1) the spatial distribution of total aerosol optical depth along the measurement routes in south-central Hebei was controlled by local terrain and population in general, with high values in downtown and suburban in the plain areas, and low values in rural areas along Taihang mountain to the west and Yan mountain to the north; 2) obviously high AODs were obtained at roads crossing points, inside densely populated area and nearby

  1. Distribution, Character, and Importance of Sedimentary Furrows in South-Central Long Island Sound

    Science.gov (United States)

    Poppe, L.; Doran, E.; Moser, M.; Forfinski, N.; Stewart, H.; Gardner, U.; Keene, J.; Christman, E.; Ackerman, S.

    2005-05-01

    The U.S. Geological Survey, in cooperation with the Connecticut Department of Environmental Protection and the National Oceanic and Atmospheric Administration, is producing detailed geologic interpretations of the sea floor in Long Island Sound to improve our understanding of the processes that control the complex distributions of sedimentary environments and benthic habitats. Although the deeper waters of the south-central Sound are generally characterized by relatively weak bottom currents and by depositional conditions, multibeam data reveal the presence of sedimentary furrows. These erosional bedforms occur in fine-grained cohesive sediments and cover an elongate east-west trending area (~80 km2) that lies approximately 5 km off Herod Point, NY, in water depths of 31-41 m. The furrows are irregularly spaced, trend east-northeast, average 9 m wide and 0.4 m deep, and can exceed 1.9 km long. Although most of the furrows appear to taper out gradually, some furrows show a "tuning fork" joining pattern. Most of these junctions open toward the east, indicating net westward sediment transport, but a few junctions open westward suggesting that the tidal regime is important to furrow formation and that the furrows can form when water flows in either direction. The sedimentary furrows in south-central Long Island Sound, which are similar to those we have previously described along the Connecticut side of the estuary, form under recurring directionally stable tidal currents, constrained by the elongate geometry and regional bathymetry of the Sound. These conditions, in turn, produce the secondary helical and turbulent flow patterns conducive to the formation of erosional furrows. Concurrently, bioturbation by crabs not only suspends sediment, but also nutclam shells and other coarse biogenic debris, which are aligned by the secondary flow and abrade the furrows as they saltate in the oscillating tides. Through resuspension due to biological activity and the subsequent

  2. Liolaemus carlosgarini and Liolaemus riodamas (Squamata: Liolaemidae), two new species of lizards lacking precloacal pores, from Andean areas of central Chile.

    Science.gov (United States)

    Esquerré, Damien; Núñez, Herman; Scolaro, José Alejandro

    2013-01-01

    Most of the lizards of the Liolaemus genus present precloacal pores in males, with few exceptions in species of the lineomaculatus and neuquensis groups, and in the elongatus-kriegi complex. The elongatus-kriegi complex, belonging to the Liolaemus (sensu stricto) subgenus, is composed of medium sized, saxicolous, viviparous and insectivorous or omnivorous lizards, distributed between the Andean and Patagonian zones of Chile and Argentina. We reviewed the taxonomic history of this group, and we describe two new species, Liolaemus carlosgarini, found in the vicinity of the Maule Lagoon, in the Maule Region, Chile, and Liolaemus riodamas, described from the population that was originally designated as Liolaemus cf ceii, from Las Damas River, near the Termas del Flaco locality, in the Libertador Bernardo O'Higgins Region, thereby based on this research L. ceii is eliminated from the species belonging to Chile. Both species have as a diagnostic character the absence of precloacal pores, and we suggest here their presumptive systematic relationships in Liolaemus. We analyzed ten species of Liolaemus, in order to perform a phylogenetic analysis based on external morphology, using mostly squamation and morphometric characters. The analysis was performed using PAUP, with the Maximum Parsimony criterion. In addition, through diaphanisation, we studied and described the osteology of the new species. We conclude that species lacking precloacal pores do not form a monophyletic group, and that constructing a phylogeny using only external morphology, at least for this group of reptiles, is insufficient to establish solid phyletic relationships. Other sort of characters should complement the morphological ones. PMID:26131484

  3. GIS Representation of Coal-Bearing Areas in North, Central, and South America

    Science.gov (United States)

    Tewalt, Susan J.; Kinney, Scott A.; Merrill, Matthew D.

    2008-01-01

    Worldwide coal consumption and international coal trade are projected to increase in the next several decades (Energy Information Administration, 2007). A search of existing literature indicates that in the Western Hemisphere, coal resources are known to occur in about 30 countries. The need exists to be able to depict these areas in a digital format for use in Geographic Information System (GIS) applications at small scales (large areas) and in visual presentations. Existing surficial geology GIS layers of the appropriate geologic age have been used as an approximation to depict the extent of coal-bearing areas in North, Central, and South America, as well as Greenland (fig. 1). Global surficial geology GIS data were created by the U.S. Geological Survey (USGS) for use in world petroleum assessments (Hearn and others, 2003). These USGS publications served as the major sources for the selection and creation of polygons to represent coal-bearing areas. Additional publications and maps by various countries and agencies were also used as sources of coal locations. GIS geologic polygons were truncated where literature or hardcopy maps did not indicate the presence of coal. The depicted areas are not adequate for use in coal resource calculations, as they were not adjusted for geologic structure and do not include coal at depth. Additionally, some coal areas in Central America could not be represented by the mapped surficial geology and are shown only as points based on descriptions or depictions from scientific publications or available maps. The provided GIS files are intended to serve as a backdrop for display of coal information. Three attributes of the coal that are represented by the polygons or points include geologic age (or range of ages), published rank (or range of ranks), and information source (published sources for age, rank, or physical location, or GIS geology base).

  4. Drought-induced sulphate release from a wetland in south-central Ontario.

    Science.gov (United States)

    Eimers, M Catherine; Watmough, Shaun A; Buttle, James M; Dillon, Peter J

    2007-04-01

    Increased sulphate (SO(4)) export from wetlands following summer droughts in central Ontario, Canada has been associated with the delayed chemical recovery of downstream surface waters following decreased sulphur (S) emissions. Prolonged summer droughts result in a decrease or cessation of stream flow, declines in wetland water table level and oxidation of reduced S compounds to SO(4), which is subsequently flushed into drainage streams when stream flow resumes. Sulphate input-output budget calculations (1983-1995 and 1999-2001) at a conifer Sphagnum swamp in the Plastic Lake catchment, indicate that SO(4) is retained in most years but is exported on a net basis following particularly severe summer droughts that result in the cessation of stream flow for more than 54 days (95% CI: 41-72 days). Hindcast calculations using long-term (1916-2000) stream discharge records from a nearby station indicate that while droughts occurred frequently in south-central Ontario over the past 85 years, sufficiently dry conditions to cause net SO(4) export occurred in only 18 of the past 85 years, and indicate a cumulative positive SO(4) balance for the swamp (i.e. net SO(4) retention). Furthermore, the S pool at the Plastic Lake swamp has been estimated to be approximately 1500 kg S/ha in the upper 40 cm peat layer, which is large compared to the amount of net SO(4) export that occurs even in years with particularly dry summers (e.g. -43 kg S/ha in 1987/88). Together, these data suggest that the wetland S pool at Plastic Lake has not been depleted by previous droughts and will continue to sustain episodic drought-related SO(4) export for the foreseeable future. PMID:16957853

  5. A SEARCH FOR CORRELATIONS BETWEEN SEA SURFACE TEMPERATURES AND OPTICAL REFLECTANCES IN CHILE AND BRAZIL DERIVED FROM AVHRR/NOAA IMAGES

    OpenAIRE

    Aníbal Gusso; Jorge Ricardo Ducati; Carlos G Cotlier; Diego A. G Lopez

    2004-01-01

    A search is made for indicators of the presence of phytoplankton, using satellite images of the Pacific (Central Chile) and Atlantic (South Brazil). AVHRR/NOAA-16 and -17 visible (1 and 2) and thermal (4 and 5) channels were used to perform a detection test, respectively, the Suspended Particulate Matter (SPM) and the Sea Surface Temperature (SST). In Brazilian waters, a positive correlation is found between SST and SPM's reflectance. This is interpreted as due to phytoplankton being more abu...

  6. USO DE ÁCIDO FÓRMICO MÁS FORMIATO DE AMONIO EN ENSILAJES DE PRADERAS PERMANENTES EN EL SUR DE CHILE Use of formic acid with ammonium formate in permanent pasture silage in the South of Chile

    Directory of Open Access Journals (Sweden)

    Enrique Siebald Sch.

    2003-07-01

    Full Text Available Es posible obtener ensilajes de alto valor nutritivo al aplicar rezagos cortos. Esto significa disponer de un material con baja concentración de MS al cosechar con corte directo, siendo normalmente necesario el uso de un aditivo. Para enfrentar esta situación se evaluó en un experimento el uso de ácido fórmico más formiato de amonio (4 L t-1 de pasto fresco, en el Instituto de Investigaciones Agropecuarias, Centro Regional de Investigación Remehue, Osorno, Chile, durante los años 1997 y 1998. Se usaron 4 hectáreas de praderas permanentes, las que se ensilaron con 54 días de rezago, el 13 y 14 de noviembre de 1997, haciendo dos silos, uno con aditivo y otro testigo sin aditivo, con descarga alternada de carros. En 1998 se evaluó la respuesta animal, utilizando 14 novillos de 375 kg de peso vivo, empleando un diseño de bloques al azar con dos tratamientos y siete repeticiones. El Ph, la digestibilidad de la MS, el N en fibra detergente ácida (N-FDA y el contenido de MS, para el ensilaje testigo y para el con aditivo fue de 4,51 y 3,97; 71.1 y 76.1; 15,5 y 12,8; 16,1 y 18,4 respectivamente. Se observó un consumo grupal al usar aditivo de 6,96 vs. 6,15 kg animal-1 d-1, siendo las ganancias de peso a los 57 días de evaluación significativamente superiores al usar aditivo 0,767 vs. 0,42 kg animal-1 d-1 (P It is possible to obtain high quality silage using short rest periods. The forage harvested under these conditions is very low in DM and if a direct cut machine is used, an additive is normally necessary. To study this situation, the use of formic acid and ammonium formate was evaluated in an experiment carried out at the Instituto de Investigaciones Agropecuarias, Centro Regional de Investigación Remehue, Osorno, Chile, during 1997 and 1998. A four hectare paddock was closed for 54 days and ensiled on November 13th and 14th, 1997, making two silages, one with additive at the rate of 4 L t-1 of fresh forage and the other as a control

  7. Lake whitefish and lake herring population structure and niche in ten south-central Ontario lakes

    Science.gov (United States)

    Carl, Leon M.; McGuiness, Fiona

    2006-01-01

    This study compares simple fish communities of ten oligotrophic lakes in south-central Ontario. Species densities and population size structure vary significantly among these lake communities depending on fish species present beyond the littoral zone. Lake whitefish are fewer and larger in the presence of lake herring than in their absence. Diet analysis indicates that lake whitefish shift from feeding on both plankton and benthic prey when lake herring are absent to a primarily benthic feeding niche in the presence of lake herring. When benthic round whitefish are present, lake whitefish size and density decline and they move lower in the lake compared to round whitefish. Burbot are also fewer and larger in lakes with lake herring than in lakes without herring. Burbot, in turn, appear to influence the population structure of benthic coregonine species. Lower densities of benthic lake whitefish and round whitefish are found in lakes containing large benthic burbot than in lakes with either small burbot or where burbot are absent. Predation on the pelagic larvae of burbot and lake whitefish by planktivorous lake herring alters the size and age structure of these populations. As life history theory predicts, those species with poor larval survival appear to adopt a bet-hedging life history strategy of long-lived individuals as a reproductive reserve.

  8. Bald eagle site management plan for the Hanford Site, south-central Washington

    International Nuclear Information System (INIS)

    The CERCLA remedial investigations of waste sites on the Hanford Site will involve lands containing or adjacent to a bald eagle nest, winter concentration areas, or communal night roost. Because these CERCLA investigations may affect bald eagles, the DOE has prepared this Bald Eagle Site Management Plan (BESMP). However, it is intended that this BESMP be used or updated so as to be also applicable to future activities that affect bald eagles on the Hanford Site. Bald eagles regularly use the US Department of Energy's (DOE) Hanford Site in south-central Washington State during winter months for roosting, perching, and foraging. Each of these activities requires buffer zones to protect eagles from human disturbances. Buffer zones developed in this plan follow recommended guidelines and are intended to be used in planning. If Hanford Site activities in the vicinity of identified bald eagle use areas are carried out in accordance with this plan, such actions are not likely to adversely affect the eagles or their habitat. Activities that may be exceptions will involve informal or formal (whichever is appropriate) consultation with the US Fish and Wildlife Service as required by the Endangered Species Act

  9. Mapping capacity to conduct health technology assessment in Central, Eastern and South-Eastern Europe

    Science.gov (United States)

    Olry de Labry Lima, Antonio; García Mochón, Leticia; Caro Martínez, Araceli; Martín Ruiz, Eva; Espín Balbino, Jaime

    2016-01-01

    Aim To provide insights into the capacity to conduct health technology assessment (HTA) in Central, Eastern, and South-Eastern Europe (CESEE), taking account of technical, financial, networking, and human resources. Methods An e-mail survey of 257 CESEE key informants involved in HTA was undertaken between March and April 2014. Contact e-mail addresses were identified from the internet. The survey questionnaire consisted of 3 sections: i) characteristics of the organization performing HTA, (ii) networking in HTA, and (iii) resources allocated for HTA. Results The survey was completed by 41 respondents representing a wide range of institutions from CESEE countries (response rate of 19.8%). Less than a quarter of respondents reported that their institutions had HTA-specific budgets, whereas the majority indicated that their institutions participated in HTA networks either at domestic or international levels. Although almost half of respondents indicated that their institutions offered HTA training, a shortage in skills training was suggested as the main barrier to HTA. Conclusion This is the first survey to thoroughly assess the state of HTA capacity in the CESEE region. To strengthen HTA capacity, CESEE countries should increase financial, technical, and training resources. To strengthen collaboration, the European Union and other international bodies should assist existing HTA networks in fulfilling their regional activities through leadership, advocacy to local policymakers, funding, and technical assistance. PMID:26935616

  10. Cave-dwelling bats (Mammalia: Chiroptera and conservation concerns in South central Mindanao, Philippines

    Directory of Open Access Journals (Sweden)

    Krizler C. Tanalgo

    2015-12-01

    Full Text Available The stable microclimate in caves provides a relatively constant habitat for many bat species in the Philippines, but human encroachment continues to disrupt this habitat and imperil many of the species roosting in the caves.  In South central Mindanao, the diversity and conservation status of cave bats remain undocumented and unexplored.  We employed mist-netting to capture bats from five different caves within the town of Kabacan, northern Cotabato, Philippines.  A total of 14 bat species were identified including the Philippine endemics Hipposideros pygmaeus and Ptenochirus jagori and the threatened Megaerops wetmorei. However, despite the declining conservation status of the bats, local disturbance such as bat hunting for bush meat and unregulated tourism are currently taking place in the caves.  Large species such as Eonycteris spelaea and Rousettus amplexicaudatus are killed almost every day for food and trade.  Therefore, the high species richness, and the presence of endemic and threatened species coupled with the occurrence of anthropogenic disturbances in caves suggests the need for an urgent and effective conservation intervention involving the local government and public community. 

  11. Constraining rates and trends of historical wetland loss, Mississippi River Delta Plain, south-central Louisiana

    Science.gov (United States)

    Bernier, Julie C.; Morton, Robert A.; Barras, John A.

    2006-01-01

    The timing, magnitude, and rate of wetland loss were described for five wetland-loss hotspots in the Terrebonne Basin of the Mississippi River delta plain. Land and water areas were mapped for 34 dates between 1956 and 2004 from historical National Wetlands Inventory (NWI) datasets, aerial photographs, and Landsat Thematic Mapper (TM) satellite images. Since 1956, the emergent land area at the five study areas in south-central Louisiana has decreased by about 50%. Comparison of the water-area curve derived from the 29 TM images with water-level records from the nearby Grand Isle, Louisiana tide gauge (NOS #8761724) clearly shows that changes in land and water areas fluctuate in response to variations in regional water levels. The magnitude of water-area fluctuations decreased from the 1980s to the 1990s as former areas of wet marsh within and immediately adjacent to the wetland-loss hotspots became permanently submerged. The most rapid wetland loss occurred during the late 1960s and 1970s. Peak wetland-loss rates during this period were two to four times greater than both the pre-1970s background rates and the most recent wetland-loss rates. These results provide constraints on predicting future delta-plain wetland losses and identify Landsat TM imagery as an important source for analyzing land- and water-area changes across the entire delta plain.

  12. Magnetic anomalies across Bastar craton and Pranhita–Godavari basin in south of central India

    Indian Academy of Sciences (India)

    I V Radhakrishna Murthy; S Bangaru Babu

    2009-02-01

    Aeromagnetic anomalies over Bastar craton and Pranhita –Godavari (P –G)basin in the south of central India could be attributed to NW –SE striking mafic intrusives in both the areas at variable depths.Such intrusions can be explained considering the collision of the Bastar and Dharwar cratons by the end of the Archaean and the development of tensile regimes that followed in the Paleoproterozoic,facilitating intrusions of mafic dykes into the continental crust.The P –G basin area,being a zone of crustal weakness along the contact of the Bastar and Dharwar cratons, also experienced extensional tectonics.The inferred remanent magnetization of these dykes dips upwards and it is such that the dykes are oriented towards the east of the magnetic north at the time of their formation compared to their present NW –SE strike.Assuming that there was no imprint of magnetization of a later date,it is concluded that the Indian plate was located in the southern hemisphere,either independently or as part of a supercontinent,for some span of time during Paleoproterozoic and was involved in complex path of movement and rotation subsequently. The paper presents a case study of the utility of aeromagnetic anomalies in qualitatively deducing the palaeopositions of the landmasses from the interpreted remanent magnetism of buried intrusive bodies.

  13. Comparison of GNSS integrated water vapor and NWM reanalysis data over Central and South America

    Science.gov (United States)

    Fernández, Laura Isabel; Natali, Maria Paula; Meza, Amalia; Mendoza, Luciano; Bianchi, Clara

    2016-07-01

    Integrated water vapor (IWV) derived from Global Navigation Satellite Systems (GNSS) and Numerical Weather Models (NWM) reanalysis data were compared in order to assess the consistency between the different datasets over the extended geographical region of Central and South America. The analysis was performed for the seven years period between 2007 and 2013. We analyzed two different NWM: the European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis data (ERA Interim) and the Modern-Era Retrospective analysis for Research and Applications (MERRA) from the National Aeronautics and Space Administration (NASA). The statistical analysis of the differences was performed in 110 GNSS sites (GPS + GLONASS), although the most interesting results came from the 73 sites which have more than 5 years of data. The selected area involves different climate types, from polar to tropical, and it is characterized by large temporal variability of the integrated total humidity content. Moreover, the scarce coverage of operational radio sounding stations is noticeable in large areas of the selected region; hence the contribution of IWV-GNSS is essential to improve the weather understanding. Considering that the atmospheric water vapor has a highly variable and complex distribution which knowledge is essential for weather prediction and local meteorological studies. This study aims to provide IWV-GNSS observations able to be assimilated by operational weather centers, for both prediction and simulation, as well for improving regional modeling.

  14. Regional and Seasonal Diet of the Western Burrowing Owl in South-Central Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Derek B. Hall, Paul D. Greger, Jeffrey R. Rosier

    2009-04-01

    We examined diets of Western Burrowing Owls (Athene cunicularia hypugaea) based on contents of pellets and large prey remains collected year-round at burrows in each of the 3 regions in south central Nevada (Mojave Desert, Great Basin Desert, and Transition region). The most common prey items, based on percent frequency of occurrence, were crickets and grasshoppers, beetles, rodents, sun spiders, and scorpions. The most common vertebrate prey was kangaroo rats (Dipodomys spp.). True bugs (Hemiptera), scorpions, and western harvest mice (Reithrodontomys megalotis) occurred most frequently in pellets from the Great Basin Desert region. Kangaroo rats (Dipodomys spp.) and pocket mice (Perognathinae) were the most important vertebrate prey items in the Transition and Mojave Desert regions, respectively. Frequency of occurrence of any invertebrate prey was high (>80%) in samples year-round but dropped in winter samples, with scorpions and sun spiders exhibiting the steepest declines. Frequency of occurrence of any vertebrate prey peaked in spring samples, was intermediate for winter and summer samples, and was lowest in fall samples. With the possible exception of selecting for western harvest mice in the Great Basin Desert region, Western Burrowing Owls in our study appeared to be opportunistic foragers with a generalist feeding strategy.

  15. Prevalence of dog intestinal nematode parasites in south central West Virginia, USA.

    Science.gov (United States)

    Savilla, Tashina M; Joy, James E; May, Jeffrey D; Somerville, Charles C

    2011-05-31

    Coprological examination was used to determine prevalence of gastrointestinal helminthes in a sample of 231 dogs (117 females and 114 males) during the summer of 2009 at a veterinary clinic in south central West Virginia, USA. Clinical signs (e.g., diarrhea, vomiting, weight gain or loss) were noted in addition to a history of anthelmintic usage. A total of 79 dogs (33.6%) were infected with one or more intestinal nematodes. Most dogs (58) were parasitized with a single species, 19 were parasitized with 2 species, and 2 were parasitized by 3 species. There was no significant difference (i.e., X(2)0.05) in prevalence of infection between female and male dogs for any of the identified nematode species. The chi-square test for equality of proportions was used to determine prevalence of infection in 3 age categories of dogs (females and males combined): young dogs (≤12 months of age); mature dogs (13-83 months); and old dogs >83 months. Prevalences of infection for Ancylostoma caninum and Toxocara canis were significantly (P0.05) in prevalence by age category for Trichuris vulpis. Dogs exhibiting clinical signs were no more likely to harbor intestinal nematodes than dogs that were asymptomatic. Additionally, dogs receiving heartworm treatment were significantly less likely to be parasitized than dogs receiving no heartworm prophylaxis. PMID:21277089

  16. Seasonal abundance and distribution of pelagic tunicates ( Chordata:Thaliacea) in the central South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIN Mao; LIN Rongcheng

    2006-01-01

    A total of 168 macro-zooplankton samples from 42 stations in the central South China Sea (12°~20° N, 111 °~ 118° E, an area of about 64 × 104 km2 ) were collected in September 1983 ( autumn), April 1984 ( spring), August 1984 (summer) and December 1984 (winter). Twenty-three species and subspecies of tunicates were found, of which Thalia democratica complex (including T. d. orientalis and T. d. echinata) and Doliolum denticulatum were the dominant species, and accounted for 95.7% ,90. 0%, 91.8% and 90. 5% of the total tunicates found in autumn, winter, spring and summer, respectively. The highest abundance ( with a mean of 2. 37 ind./m3 ) occurred in autumn. There are strong correlations between the abundances of the tunicates and those of phytoplankton and chlorophyll a concentration. However, tunicates also aggregate in areas with low primary production in the autumn survey, probably due to the water circulation pattern.

  17. Moho geometry along a north-south passive seismic transect through Central Australia

    Science.gov (United States)

    Sippl, Christian

    2016-04-01

    Receiver functions from a temporary deployment of 25 broadband stations along a north-south transect through Central Australia are used to retrieve crustal and uppermost mantle structural constraints from a combination of different methods. Using H-K stacking as well as receiver function inversion, overall thick crust with significant thickness variation along the profile (40 to ≥ 55 km) is found. Bulk crustal vp/vs values are largely in the felsic to intermediate range, with the southernmost stations on the Gawler Craton exhibiting higher values in excess of 1.8. A common conversion point (CCP) stacking profile shows three major discontinuities of the crust-mantle boundary: (1) a two-sided Moho downwarp beneath the Musgrave Province, which has previously been associated with the Neoproterozoic to early Cambrian Petermann Orogeny, (2) a Moho offset along the Redbank Shear Zone further north attributed to the Middle to Late Paleozoic Alice Springs Orogeny, and (3) another Moho offset further north, located at the boundary between the Davenport and Warramunga Provinces, which has not been imaged before. In all cases, the difference in crustal thickness between the two sides of the offset is > 8-10 km. Unlike the two southern Moho offsets, the northernmost one does not coincide with a prominent gravity anomaly. Its location and the absence of known reactivation events in the region make it likely that it belongs to a Proterozoic suture zone that marks a previously unknown block boundary within the North Australian Craton.

  18. The quantification and distribution of pollution Pb at a woodland in rural south central Ontario, Canada

    International Nuclear Information System (INIS)

    Lead concentrations and Pb isotope ratios were measured in the forest floor, mineral soil and vegetation at a white pine and a sugar maple stand in a woodland in south central Ontario. Lead concentrations decreased and 206Pb/207Pb ratios increased with mineral soil depth reflecting the mixing of pollution and natural Pb sources. Lead concentrations and 206Pb/207Pb ratios at 20-30 cm depth were ∼6-7 mg/kg and 1.31-1.32, respectively. Assuming an integrated 206Pb/207Pb ratio in deposition over time of 1.18, estimated from lichen measurements and published data for the region, approximately 65% of Pb in the surface (0-1 cm) mineral soil is from anthropogenic sources. Approximately 90% of pollution Pb is found in the 0-10 cm soil layer (Ah) and less than 3% of the pollution Pb is present in the forest biomass and mull-type forest floor combined. Despite low Pb concentrations in vegetation (2, respectively. - The distribution of pollution lead was determined at a woodland through the use of stable leads isotopes

  19. Diagenetic destruction of primary reservoir porosity in Viola Limestone, south-central Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Grammer, M.G.

    1985-02-01

    The Viola Limestone in south-central Oklahoma is a Middle and Upper Ordovician carbonate unit interpreted as being deposited on a carbonate ramp within and peripheral to the Southern Oklahoma aulacogen. Depositional environments within the study area ranged from anaerobic deep ramp through aerobic middle and shallow ramp. TOC analyses of the lower anaerobic deep-ramp facies suggest that, at least locally, the Viola is a potential hydrocarbon source rock. Detailed petrographic examination of the Viola indicates that primary porosity in the shallow-ramp skeletal packstones and grainstones was initially quite high. This combination of source potential and original porosity should make the Viola an attractive target for hydrocarbons in southern Oklahoma. The Viola, however, has been subjected to a complex sequence of diagenetic events that have extensively altered the sediments and occluded much of the primary porosity. A thorough understanding of the timing and nature of these events can be critical in evaluating the economic potential of the Viola. Petrographic evidence combined with the use of cathodoluminescence indicates that several generations of calcite cementation occurred within the shallow-ramp packstones and grainstones. An initial phase of very early, possibly synsedimentary, marine cementation is evidenced by cloudy, inclusion-rich syntaxial cements on echinoderm fragments. This early phase of cementation was followed by several generations of clear syntaxial calcite, prismatic calcite, blocky mosaic calcite, and bladed mosaic calcite, all of which indicate changes in the pore-water chemistry after precipitation of the inclusion-rich cements.

  20. Phylogeny and biogeography of Poecilia (Cyprinodontiformes: Poeciliinae) across Central and South America based on mitochondrial and nuclear DNA markers.

    Science.gov (United States)

    Ho, Adeljean L F C; Pruett, Christin L; Lin, Junda

    2016-08-01

    Poeciliids are a diverse group of small Neotropical fishes, and despite considerable research attention as models in ecology and evolutionary biology, our understanding of their biogeographic and phylogenetic relationships is still limited. We investigated the phylogenetic relationships of South and Central American Poecilia, by examining 2395 base pairs of mitochondrial DNA (ATPase 8/6, COI) and nuclear DNA (S7) for 18 species across six subgenera. Fifty-eight novel sequences were acquired from newly collected specimens and 20 sequences were obtained from previously published material. Analyses of concatenated and partitioned mitochondrial DNA and nuclear DNA sets resulted in a well-supported phylogeny that resolved several monophyletic groups corresponding to previously hypothesized subgenera and species complexes. A divergence-dating analysis supported the hypothesis of the genus Poecilia dispersing into Central America in the early Pliocene (ancestors of Psychropoecilia+Allopoecilia+Mollienesia: 7.3-2.0Mya) from predominantly South America. Subsequently, one lineage (subgenus Allopoecilia: 5.1-1.3Mya) expanded deeper into South America from Lower-Central America, and one lineage expanded from Nuclear-Central America into South America (subgenus Mollienesia: 0.71-0.14Mya). The subgenus Mollienesia diverged into three monophyletic groups that can be identified by nuptial male dorsal fin morphology and inner jaw dentition. A subclade of the unicuspid short-fins (subgenus Mollienesia) was the lineage that expanded into South America during the middle Pleistocene. Species in this subclade are now distributed across northern South America, where they are partially sympatric with Allopoecilia. However the P. (A.) caucana complex was not monophyletic, with P. (A.) wandae clustering in the Mollienesia subclade that expanded into South America. It is apparent that characters (body size, scale count, pigmentation, and gonopodium morphology) used to define the P. (A

  1. Combined Active and Passive Seismology to Study Continental Collision; Central South Island of New Zealand

    Science.gov (United States)

    Stern, T.; Okaya, D.; Baldock, G.; Scherwath, M.

    2005-12-01

    Central South Island of New Zealand is a continental region that has undergone both collision and strike-slip shear in the late Tertiary. From a tectonics, or rock-mechanics, view-point there is an interest in how the crust and mantle have been both thickened and sheared. The South Island Geophysical Transect (SIGHT) and the Southern Alps Passive Seismic Experiment (SAPSE) - both jointly funded US-NZ programs - studied these processes. Some of the most important findings came about by merging data from passive and active seismology. Three specific examples will be discussed: 1. Teleseismic P-wave delays from earthquakes in the Western Pacific are used to map a ~ 0.8-1 s speed-up in the mantle right beneath the region of thickest crust and highest topography of the collision zone. Forward modeling of this velocity anomaly shows that the amplitude of the anomaly can be explained by a 100 km-thick body that has a 7% in increase in P-wave speed. From the spatial pattern of the P-wave residuals we can also show that the high-speed body is about 80-100 km wide and roughly vertically disposed beneath the crustal root. The shape and position of the high-speed body beneath the seismically determined crustal root is consistent with it being thickened, and therefore cold, mantle lithosphere that has uniformly strained into a roughly symmetric root beneath the collision zone. 2. Pn anisotropy measurements from our onshore-offshore seismic shooting program allowed us to make mutually perpendicular determinations of Pn wave speeds at three localities. P-wave anisotropies of up to 11 ± 3%, 6.5 ± 2.5% and 0 ± 3%, were measured, depending on the distance of the measurement from the surface trace of the plate boundary (the Alpine Fault). These are necessarily minimum anisotropy values because it assumes that the two axes of measurement are those of minimum and maximum wave speed. Combining these results with SKS splitting values of ~ 2 s from passive seismology allowed us to make

  2. DETECTION OF LOCAL SITE CONDITIONS INFLUENCING EARTHQUAKE SHOCK AND SECONDARY EFFECTS IN THE VALPARAISO AREA IN CENTRAL-CHILE USING REMOTE SENSING AND GIS METHODS

    Directory of Open Access Journals (Sweden)

    Barbara Theilen-Willige

    2011-01-01

    Full Text Available The potential contribution of remote sensing and GIS techniques to earthquake hazard analysis was investigated in Valparaiso in Chile in order to improve the systematic, standardized inventory of those areas that are more susceptible to earthquake ground motions or to earthquake related secondary effects such as landslides, liquefaction, soil amplifications, compaction or even tsunami-waves. Geophysical, topographical, geological data and satellite images were collected, processed, and integrated into a spatial database using Geoinformation Systems (GIS and image processing techniques. The GIS integrated evaluation of satellite imageries, of digital topographic data and of various open-source geodata can contribute to the acquisition of those specific tectonic, geomorphologic/ topographic settings influencing local site conditions in Valparaiso, Chile. Using the weighted overlay techniques in GIS, susceptibility maps were produced indicating areas, where causal factors influencing near- surface earthquake shock occur aggregated. Causal factors (such as unconsolidated sedimentary layers within a basin’s topography, higher groundwater tables, etc. summarizing and interfering each other, rise the susceptibility of soil amplification and of earthquake related secondary effects. This approach was used as well to create a tsunami flooding susceptibility map. LANDSAT Thermal Band 6-imageries were analysed to get information of surface water currents in this area.

  3. Importance of water quality on plant abundance and diversity in high-alpine meadows of the Yerba Loca Natural Sanctuary at the Andes of north-central Chile Importancia de la calidad del agua sobre la abundancia y diversidad vegetal en vegas altoandinas del Santuario Natural Yerba Loca en los Andes de Chile centro-norte

    Directory of Open Access Journals (Sweden)

    ROSANNA GINOCCHIO

    2008-12-01

    Full Text Available Porphyry Cu-Mo deposits have influenced surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS, central Chile (33°15' S, 70°18' W. Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and La Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Pb and Fe. Data on species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitals with Cu-rich waters while Festuca magellanica, Patosia clandestina, Plantago barbata, Werneria pygmea, and Erigeron andícola are abundant in habitals with dilute waters.Los megadepósitos de pórfidos de Cu-Mo han influido sobre la calidad de las aguas superficiales en las zonas altoandinas del centro-norte de Chile desde el Mioceno. Estas alteraciones en la calidad de las aguas podrían afectar negativamente a la vegetación presente en las vegas altoandinas, ya que las aguas acidas y ricas en metales son altamente tóxicas para las plantas. En este estudio se evaluó el efecto de la calidad de las aguas en la abundancia y diversidad florística de las vegas altoandinas del Santuario de la Naturaleza Yerba Loca (SNYL, en Chile central (33

  4. Soil respiration rate on the contrasting north- and south-facing slopes of a larch forest in central Siberia

    International Nuclear Information System (INIS)

    In an attempt to evaluate global warming effects, we measured the soil respiration of the contrasting north- and south- facing slopes of a larch forest in central Siberia, located at Tura City in the Krasnoyarsk District, Russia. The north-facing slope is assumed to be the present condition while the south-facing slope may stand for the future warm condition. As a result of differences in solar radiation, there were clear differences between the north- and south- facing slopes in terms, for example, of the active layer as the growth rate of larch trees. The soil respiration rate was higher on the south-facing slope than on the north-facing slope. At the temperature of 15°C, soil respiration rate of the south-facing slope was ca. 6.2 μ mol CO2 * m-2s-1, which was about 0.6 times lower than that of broad-leaved forests in Hokkaido. There was an exponential correlation between soil temperature at 10 cm depth and the efflux of CO2 from the soil surface. Various conditions (soil temperature,. nitrogen content and soil water content) seemed to be more favorable for soil respiration on the south-facing slope. (author)

  5. Combining point and distributed snowpack data with landscape-based discretization for hydrologic modeling of the snow-dominated Maipo River Basin, in the semi-arid Andes central Chile

    Science.gov (United States)

    Videla Giering, Y. A., III; McPhee, J. P.

    2015-12-01

    Snow hydrology in mountain environments plays an important role in the availability of hydrological resources in warm climate areas and height effects, since the magnitude of snowpack, its spatial and temporal distribution is very important to determine the availability of water in the snowmelt season and take forward different productive activities This investigation models and assess the main phenomena hydrological cycle of snow using the software Cold Region Hydrological Model (Pomeroy et al., 2007). The software is a physically based model developed by the centre for hydrology, University of Saskatchewan. The aim of this model is to have a better understanding of hydrological processes involved in cold environments, which are particular in the sense that a host of specific phenomena such as snow and ice accumulation, transport and melt, infiltration through frozen soils, and the like, control the hydrograph timing) The analysis involved the development of a hydrologic model for the Upper Maipo River Basin, with elevations between 800 and 6500 meters above sea level and 5000-km^2 watershed in the Andes of Central Chile which supplies water resources to the capital city of Santiago (7 million inhabitants), to a thriving agricultural region, as well as to hydropower and large mining activities. The paper concludes that there is a differential distribution of snow cover in the study area, determined mainly by steep terrain geomorphology. These factors have been considered in the parameterization of the model, showing considerable variation in storage time, redistributions by blowing snow, melting intervals, infiltration rates and drainage basin. The fictional scenarios modeled demonstrate noticeable changes in the hydrograph, showing the fragile climate and hydrological condition of this basin of Central Chile.

  6. GREYBULL SANDSTONE PETROLEUM POTENTIAL ON THE CROW INDIAN RESERVATION, SOUTH-CENTRAL MONTANA

    Energy Technology Data Exchange (ETDEWEB)

    David A. Lopez

    2000-12-14

    Evaluation of the Lower Cretaceous Greybull Sandstone on the Crow Indian Reservation for potential stratigraphic traps in the valley-fill sandstone was the focus of this project. The Crow Reservation area, located in south-central Montana, is part of the Rocky Mountain Foreland structural province, which is characterized by Laramide uplifts and intervening structural basins. The Pryor and Bighorn mountains, like other foreland uplifts, are characterized by asymmetrical folds associated with basement-involved reverse faults. The reservation area east of the mountains is on the northwestern flank of the Powder River Basin. Therefore, regional dips are eastward and southeastward; however, several prominent structural features interrupt these regional dips. The nearly 4,000 mi{sup 2} reservation is under explored but has strong potential for increased oil and gas development. Oil and gas production is well established in the Powder River Basin of Wyoming to the south as well as in the areas north and west of the reservation. However, only limited petroleum production has been established within the reservation. Geologic relations and trends indicate strong potential for oil and gas accumulations, but drilling has been insufficient for their discovery. The Greybull Sandstone, which is part of the transgressive systems tract that includes the overlying Fall River Sandstone, was deposited on a major regional unconformity. The erosional surface at the base of the Greybull Sandstone is the +100 Ma, late Aptian-Early Albian regional unconformity of Weimer (1984). This lowstand erosional surface was controlled by a basin-wide drop in sea level. In areas where incised Greybull channels are absent, the lowstand erosional unconformity is at the base of the Fall River Sandstone and equivalent formations. During the pre-Greybull lowstand, sediment bypassed this region. In the subsequent marine transgression, streams began to aggrade and deposit sand of the lower Greybull Sandstone

  7. Diverging Histories of the Liberty Creek and Iceberg Lake Blueschist Bodies, south central Alaska

    Science.gov (United States)

    Day, E. M.; Pavlis, T. L.; Amato, J. M.

    2011-12-01

    New studies of the Liberty Creek and Iceberg Lake blueschist bodies of south central Alaska indicate that despite structural similarities, these blueschist bodies are derived from a different protolith and were metamorphosed to blueschist facies at distinctly different times. Both blueschists are located just south of the Border Ranges Fault (BRF) within outcrop belts of the McHugh Complex, a low-grade mélange assemblage that is now known from detrital zircon studies to consist of two distinct assemblages: a Jurassic to Earliest Cretaceous assemblage and a Late Cretaceous assemblage. The BRF is a megathrust system that represents the Late Triassic-Early Jurassic initiation of southern Alaskan subduction. Large scale (1:24,000) mapping revealed similar fabric overprint histories, epitomized by a previously undescribed youngest vertical N-S trending crenulation cleavage in both blueschist bodies which implies a structural correlation despite their separation of ~100 kilometers along strike. Despite structural similarities detrital zircon studies show that the Liberty Creek and Iceberg Lake blueschists do not have a similar maximum age of deposition. Thirteen samples from the Iceberg Lake blueschist were processed, none of which produced detrital zircons. Samples from the McHugh Complex greenschists that surround the Iceberg Lake blueschist produced numerous zircons indicating a Late Jurassic (~160 Ma) maximum age of deposition. Three out of sixteen samples from the Liberty creek blueschist produced detrital zircons indicating maximum depositional ages ranging from Late Jurassic (~160.1 Ma, n=64 grains; ~152.25 Ma, n=68 grains) to Early Cretaceous (~137.1 Ma, n=95 grains). The Late Jurassic dates are consistent with maximum depositional ages determined by Amato and Pavlis (2010) for McHugh Complex rocks along Turnagain Arm near Anchorage, AK. Sisson and Onstott (1986) reported a metamorphic cooling age of 185 Ma for the Iceberg Lake blueschist, thus, although no

  8. Revisiting chlorophyll data along the coast in north-central Chile, considering multiscale environmental variability Reinterpretando datos de clorofila en la costa centro-norte de Chile, considerando variabilidad ambiental de multiescala

    Directory of Open Access Journals (Sweden)

    VIVIAN MONTECINO

    2006-06-01

    Full Text Available Phytoplankton abundance in the surface mixed layer of the coastal ocean responds to environmental changes at various time scales. Here the "warm", "cold" and "neutral" phases of "three environmental cycles" have been jointly considered to assess chlorophyll-a (Chl-a biomass variability for both the active and relaxed phases of the local, wind-driven coastal upwelling: (i the interannual ENSO cycle (ii the annual (seasonal cycle and (iii the intraseasonal cycle associated with equatorially-sourced, ocean trapped-waves along the coast in northern Chile. The main goal of this study is to quantitatively assess the variability of the depth- integrated Chl-a biomass in the euphotic zone (¾Chl-a in terms of an overall "environmental condition" over a 50 km upwelling sensitive coastal strip, revisiting published and unpublished Chl-a ship (Cship = Chl-a + Phaeopigments data. All possible "environmental conditions" combinations were further ranked into seven "environmental indices" ranging from 0 ("absolutely cold" to 6 ("absolutely warm". Out of 332 samples of ¾Chl-a, 198/134 were obtained during active/relaxed upwelling conditions from which 24/38 and 30/36 samples were associated with the simultaneous occurrence of at least two "cold"/"warm" phases of the three environmental cycles ("cold"/"warm" environmental conditions, respectively. Lower ¾Chl-a values during "cold" and "warm" environmental conditions relative to the "neutral" ones reached statistical significance for both active and relaxed conditions (144/60 samples respectively. Higher turbulent mixing during "cold" environmental conditions and a deeper nutricline during "warm" ones would explain lower ¾Chl-a-values. Satellite chlorophyll (Csat data obtained in clear skies (active upwelling only, showed a similar distribution to those of ¾Chl-a when classified into the corresponding "environmental indices". These results suggest that during "neutral" (transitional "environmental conditions

  9. Income Inequality in Chile: 1990-2006

    OpenAIRE

    Alain Hourton

    2012-01-01

    The entrance of Chile to the Organization for the Economic Cooperation and Development, as the first South American country and second after Mexico in Latin America, sets a landmark in the development path that since the beginning of the 1990s decade has seemed to lead this country to a privileged position in the region. Given the reforms taken by the military regime in the 1980s, Chile is one of the most market-oriented countries in Latin America, with Free Trade Agreements and Economical Pa...

  10. Detrital Zircon Geochronology of Cretaceous and Paleogene Strata Across the South-Central Alaskan Convergent Margin

    Science.gov (United States)

    Bradley, Dwight; Haeussler, Peter; O'Sullivan, Paul; Friedman, Rich; Till, Alison; Bradley, Dan; Trop, Jeff

    2009-01-01

    Ages of detrital zircons are reported from ten samples of Lower Cretaceous to Paleogene metasandstones and sandstones from the Chugach Mountains, Talkeetna Mountains, and western Alaska Range of south-central Alaska. Zircon ages are also reported from three igneous clasts from two conglomerates. The results bear on the regional geology, stratigraphy, tectonics, and mineral resource potential of the southern Alaska convergent margin. Chugach Mountains - The first detrital zircon data are reported here from the two main components of the Chugach accretionary complex - the inboard McHugh Complex and the outboard Valdez Group. Detrital zircons from sandstone and two conglomerate clasts of diorite were dated from the McHugh Complex near Anchorage. This now stands as the youngest known part of the McHugh Complex, with an inferred Turonian (Late Cretaceous) depositional age no older than 91-93 Ma. The zircon population has probability density peaks at 93 and 104 Ma and a smattering of Early Cretaceous and Jurassic grains, with nothing older than 191 Ma. The two diorite clasts yielded Jurassic U-Pb zircon ages of 179 and 181 Ma. Together, these findings suggest a Mesozoic arc as primary zircon source, the closest and most likely candidate being the Wrangellia composite terrane. The detrital zircon sample from the Valdez Group contains zircons as young as 69 and 77 Ma, consistent with the previously assigned Maastrichtian to Campanian (Late Cretaceous) depositional age. The zircon population has peaks at 78, 91, 148, and 163 Ma, minor peaks at 129, 177, 330, and 352 Ma, and no concordant zircons older than Devonian. A granite clast from a Valdez Group conglomerate yielded a Triassic U-Pb zircon age of 221 Ma. Like the McHugh Complex, the Valdez Group appears to have been derived almost entirely from Mesozoic arc sources, but a few Precambrian zircons are also present. Talkeetna Mountains - Detrital zircons ages were obtained from southernmost metasedimentary rocks of the

  11. Specialized consultant in radiological safety to the south central hospital of high speciality, PEMEX. II.- August of 2001

    International Nuclear Information System (INIS)

    The south central hospital of high speciality, dependent of PEMEX, It request consultant of the ININ to be able to maintain their sanitary license for the use of X-ray equipment for the radiologic diagnostic.The proposal of the ININ was to be a program of technical attendance, schedule monthly to be able to solve the observations that are presented in the use of those equipment, and that the hospital can conserve its respective sanitary license.(Author)

  12. Specialized consultant in radiological safety to the south central hospital of high speciality, PEMEX. V. - November of 2001

    International Nuclear Information System (INIS)

    The south central hospital of high speciality, dependent of PEMEX, It request consultant of the ININ to be able to maintain their sanitary license for the use of X-ray equipment for the radiologic diagnostic.The proposal of the ININ was to be a program of technical attendance, schedule monthly to be able to solve the observations that are presented in the use of those equipment, and that the hospital can conserve its respective sanitary license.(Author)

  13. Dental caries among children visiting a mobile dental clinic in South Central Kentucky: a pooled cross-sectional study

    OpenAIRE

    Dawkins, Erika; Michimi, Akihiko; Ellis-Griffith, Gregory; Peterson, Tina; Carter, Daniel; English, Gary

    2013-01-01

    Background Dental caries is one of the most common chronic childhood diseases affecting a large portion of children in the United States. The prevalence of childhood dental caries in Kentucky is among the highest in the nation. The purposes of this study are to (1) compare sociodemographic differences between caries and no caries groups and (2) investigate factors associated with untreated dental caries among children who visited a mobile dental clinic in South Central Kentucky. Methods Study...

  14. An assessment of fire occurrence regime and performance of Canadian fire weather index in south central Siberian boreal region

    Directory of Open Access Journals (Sweden)

    T. Chu

    2014-07-01

    Full Text Available Wildfire is the dominant natural disturbance in Eurasian boreal region, which acts as a major driver of the global carbon cycle. An effectiveness of wildfire management requires suitable tools for fire prevention and fire risk assessment. This study aims to investigate fire occurrence patterns in relation to fire weather conditions in the remote south central Siberia region. The Canadian Fire Weather Index derived from large-scale meteorological reanalysis data was evaluated with respects to fire regimes during 14 consecutive fire seasons in south central Siberian environment. All the fire weather codes and indices, including the Fine Fuel Moisture Code (FFMC, the Duff Moisture Code (DMC, the Drought Code (DC, the Buildup Index (BUI, the Initial Spread Index (ISI, and the Fire Weather Index (FWI, were highly reflected inter-annual variation of fire activity in south central Siberia. Even though human-caused fires were major events in Russian boreal forest including south central Siberia, extreme fire years were strongly correlated with ambient weather conditions (e.g. Arctic Oscillation, air temperature, relative humidity and wind, showing by in-phase (or positive linear relationship and significant wavelet coherence between fire activity and DMC, ISI, BUI, and FWI. Time series observation of 14 fire seasons showed that there was an average of about 3 months lags between the peaks of fire weather conditions and fire activity, which should take into account when using coarse scale fire weather indices in the assessment of fire danger in the study area. The results are expected to contribute to a better reconstruction and prediction of fire activity using large-scale reanalysis data in remote regions in which station data are very few.

  15. INVESTIGATION OF STOCK ILLIQUIDITY ON CENTRAL AND SOUTH EAST EUROPEAN MARKETS IN NAÏVE PORTFOLIO FRAMEWORK

    OpenAIRE

    Vidović, Jelena

    2013-01-01

    This paper questions existence of illiquidity premium on 8 Central and South East European stock markets. Using the ILLIQ illiquidity measure proposed by Amihud (2002) we investigate liquidity of each stock. Naïve portfolio diversification is applied in forming liquidity sorted portfolios. These portfolios were formed using daily data in the half-year period and in the second part of analysis by using daily data within one month. Performance of these portfolios was observed in the half-year p...

  16. Specialized consultant in radiological safety to the south central hospital of high speciality, PEMEX. IV. - October of 2001

    International Nuclear Information System (INIS)

    The south central hospital of high speciality, dependent of PEMEX, It request consultant of the ININ to be able to maintain their sanitary license for the use of X-ray equipment for the radiologic diagnostic.The proposal of the ININ was to be a program of technical attendance, schedule monthly to be able to solve the observations that are presented in the use of those equipment, and that the hospital can conserve its respective sanitary license.(Author)

  17. Environmental noise and annoyance in adults: Research in central, eastern and south-eastern Europe and newly independent states

    OpenAIRE

    Jurgita Lekaviciute; Lubica Argalasova-Sobotova

    2013-01-01

    Research work on the adverse effects of noise on annoyance in adults is well documented in Western Europe, but there is a knowledge gap concerning this type of research in Central and Eastern Europe (CEE), South-East Europe (SEE), and Newly Independent States (NIS). The objective of this review was to present findings and to propose future research directions for the studies on the effects of environmental noise on annoyance in adults conducted in these countries. After systematic search in a...

  18. Environmental noise and sleep disturbance: Research in central, eastern and south-eastern Europe and newly independent states

    OpenAIRE

    Gordana Ristovska; Jurgita Lekaviciute

    2013-01-01

    Countries from South-East Europe (SEE), Central and Eastern Europe (CEE) and Newly Independent States (NIS) are in the process of harmonization with European environmental noise legislation. However, research work on noise and health was performed in some countries independently of harmonization process of adoption and implementation of legislation for environmental noise. Aim of this review is to summarize available evidence for noise induced sleep disturbance in population of CEE, SEE and N...

  19. Noise and childrens health: Research in Central, Eastern and South-Eastern Europe and Newly Independent States

    OpenAIRE

    Katarina Paunovic

    2013-01-01

    Many reviews have documented the adverse effects of noise on children′s health, but the international scientific community was previously unfamiliar with noise research in Central and Eastern Europe (CEE), South-East Europe (SEE), and Newly Independent States (NIS). The aim of this review was to present studies on the effects of noise on children′s health, conducted in aforementioned countries in the second half of the 20 th century, interpret their findings, and criticize their methodology a...

  20. Community response to noise: Research in Central, Eastern and South-Eastern Europe and Newly Independent States

    OpenAIRE

    Sonja Jeram; Jurgita Lekaviciute; Zanda Krukle; Lubica Argalasova-Sobotova; Gordana Ristovska; Katarina Paunovic; Malgorzata Pawlaczyk-Luszczynska

    2013-01-01

    The systems of public complaints on environmental noise were reviewed in seven countries of Central and Eastern Europe (CEE), South-East Europe (SEE), and Newly Independent States (NIS). Public complaints remain an important issue due to differences in public sensitivity to noise and due to several cases where a measurement of noise intensity does not give a satisfying solution to the problem. The unresolved problem remaining in the residential neighborhoods is the noise from pubs and restaur...

  1. A Web Platform Development to Perform Thematic Accuracy Assessment of Sugarcane Mapping in South-Central Brazil

    OpenAIRE

    Arley Ferreira de Souza; Bernardo Friedrich Theodor Rudorff; Daniel Alves Aguiar; Marcio Pupin Mello; Marcos Adami

    2012-01-01

    The ability to monitor sugarcane expansion in Brazil, the world’s largest producer and exporter of sugar and second largest producer of ethanol, is important due to its agricultural, economic, strategic and environmental relevance. With the advent of flex fuel cars in 2003 the sugarcane area almost doubled over the last decade in the South-Central region of Brazil. Using remote sensing images, the sugarcane cultivation area was annually monitored and mapped between 2003 and 2012, a period of ...

  2. High level of molecular and phenotypic biodiversity in Jatropha curcas from Central America compared to Africa, Asia and South America

    OpenAIRE

    Montes Osorio, Luis; Torres Salvador, Andres; Jongschaap, Raymond Elmar; Azurdia Perez, Cesar; Berduo Sandoval, Julio; Trindade, Luisa; Visser, Richard Gerardus; van Loo, Eibertus

    2014-01-01

    Background The main bottleneck to elevate jatropha (Jatropha curcas L.) from a wild species to a profitable biodiesel crop is the low genetic and phenotypic variation found in different regions of the world, hampering efficient plant breeding for productivity traits. In this study, 182 accessions from Asia (91), Africa (35), South America (9) and Central America (47) were evaluated at genetic and phenotypic level to find genetic variation and important traits for oilseed production. Results G...

  3. Specialized consultant in radiological safety to the south central hospital of high speciality, PEMEX. I. - July of 2001

    International Nuclear Information System (INIS)

    The south central hospital of high speciality, dependent of PEMEX, It request consultant of the ININ to be able to maintain their sanitary license for the use of X-ray equipment for the radiologic diagnostic.The proposal of the ININ was to be a program of technical attendance, schedule monthly to be able to solve the observations that are presented in the use of those equipment, and that the hospital can conserve its respective sanitary license.(Author)

  4. Specialized consultant in radiological safety to the south central hospital of high speciality, PEMEX. III.- September of 2001

    International Nuclear Information System (INIS)

    The south central hospital of high speciality, dependent of PEMEX, It request consultant of the ININ to be able to maintain their sanitary license for the use of X-ray equipment for the radiologic diagnostic.The proposal of the ININ was to be a program of technical attendance, schedule monthly to be able to solve the observations that are presented in the use of those equipment, and that the hospital can conserve its respective sanitary license.(Author)

  5. In vitro antimicrobial activity of plants used in traditional medicine in Gurage and Silti Zones, south central Ethiopia

    OpenAIRE

    Teka Sahile, Alemtshay; Rondevaldova, Johana; Asfaw, Zemede; Demissew, Sebsebe; Van Damme, Patrick; Kokoska, Ladislav; Vanhove, Wouter

    2015-01-01

    Background: To overcome the escalating problems associated with infectious diseases and drug resistance, discovery of new antimicrobials is crucial. The present study aimed to carry out in vitro antimicrobial analysis of 15 medicinal plant species selected according to their traditional medicinal uses in Gurage and Silti Zones, south central Ethiopia. Methods: Ethanol extracts of various plant parts were investigated for their antimicrobial activity against 20 bacterial and one yeast stra...

  6. Stratigraphy and depositional environments of Catahoula Formation sandstones and associated facies in south-central Mississippi

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, C.P. (Univ. of Southern Mississippi, Hattiesburg (USA)); Day, L.A. (Geraghty and Miller, Baton Rouge, LA (USA))

    1990-09-01

    Surface and subsurface studies of the Catahoula Formation in a seven county area of south-central Mississippi have revealed major problems and misconceptions regarding Neogene stratigraphy and geological mapping in this part of the Gulf basin. The results of these investigations show that the traditional stratigraphic subdivisions of the up-dip Neogene section in Mississippi are invalid, and that the fundamental criteria for defining rock stratigraphic units at the formation rank are nonexistent. Although the base of the Neogene section is reasonably well defined by virtue of its relatively continuous contact with the Bucatunna Formation (Oligocene Vicksburg Group), a mappable bounding sequence above the Catahoula-Bucatunna Formation contact does not exist in the study area. An overall fine-grained interval above the Catahoula Formation appears to wedge out before reaching outcrop. Hence, differentiation between up-dip sandy gravels of the Catahoula and similar facies of the Citronelle Formation is difficult. Further complicating the problem of stratigraphic unit discrimination is the discovery of sandy gravels within the Hattiesburg Formation interval. A subsurface analysis in this study area revealed that the Catahoula Formation, as defined by Day, attains a thickness of 625 ft and has a rough three-tiered stratigraphy: (a) a basal unit composed of sands and subordinate fine-grained facies; (b) a relatively fine-grained middle unit composed of silts and clays with recurrent, discontinuous, sand bodies; and (c) an upper unit composed largely of sand and gravels. This study confirmed that most of these sediments are the product of fluvial channel and associated floodplain deposition. However, in the basal unit deltaic facies appear to be preserved on outcrop in Smith County and perhaps in a mild structural depression in the southwest portion of the study area.

  7. Atmospheric circulation associated with extreme generalized frosts persistence in central-southern South America

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Gabriela V. [Centro de Investigaciones Cientificas y Transferencia de Tecnologia a la Produccion, Diamante (CICYTTTP-CONICET), Diamante, Entre Rios (Argentina); Berri, Guillermo J. [Servicio Meteorologico Nacional - CONICET, Buenos Aires (Argentina)

    2012-03-15

    Generalized frosts (GF) in central-southern South America have a strong impact due to their spatial extension, and they are especially important when they become persistent. This paper aims at identifying the atmospheric circulation features that determine the extreme GF persistence, i.e. very persistent and without persistence, and the differences between them, during the 1961-1990 winters. Since the GF without persistence group outnumbers the other one, two subgroups are composed with events selected from winters with maximum and minimum frequency of GF occurrence, respectively. Additionally, the individual event of July 1988 within the very persistent GF group is analyzed due to its exceptional persistence. GF persistence is mainly conditioned by two large-scale dynamic factors. One is the Rossby wave train propagation across the Pacific Ocean, and the other one is the location with respect to the continent and the magnitude of the confluence in the jet entrance region in subtropical latitudes. A predominantly meridional Rossby wave train propagation with a confluence region to the west of the continent prior to the event favors GF with intermediate (null) persistence depending on the greater (lesser) jet acceleration. This is conditioned by the magnitude of the confluence, which, in turn, depends on the disposition of the wave train propagation pattern. Instead, an essentially zonal propagation with a confluence region to the east of the continent favors the GF persistence for several days, yet if there is no confluence the event does not persist. The greatest persistence of an event combines the confluence/diffluence of the jet entrance/exit region, which depends on the disposition with respect to the continent of the zonally propagating Rossby wave trains. (orig.)

  8. Prevalence of malaria infection in Butajira area, south-central Ethiopia

    Directory of Open Access Journals (Sweden)

    Woyessa Adugna

    2012-03-01

    Full Text Available Abstract Background In 2005, the Ethiopian government launched a massive expansion of the malaria prevention and control programme. The programme was aimed mainly at the reduction of malaria in populations living below 2,000 m above sea level. Global warming has been implicated in the increase in the prevalence of malaria in the highlands. However, there is still a paucity of information on the occurrence of malaria at higher altitudes. The objective of this study was to estimate malaria prevalence in highland areas of south-central Ethiopia, designated as the Butajira area. Methods Using a multi-stage sampling technique, 750 households were selected. All consenting family members were examined for malaria parasites in thick and thin blood smears. The assessment was repeated six times for two years (October 2008 to June 2010. Results In total, 19,207 persons were examined in the six surveys. From those tested, 178 slides were positive for malaria, of which 154 (86.5% were positive for Plasmodium vivax and 22 (12.4% for Plasmodium falciparum; the remaining two (1.1% showed mixed infections of Plasmodium falciparum and Plasmodium vivax. The incidence of malaria was higher after the main rainy season, both in lower lying and in highland areas. The incidence in the highlands was low and similar for all age groups, whereas in the lowlands, malaria occurred mostly in those of one to nine years of age. Conclusion This study documented a low prevalence of malaria that varied with season and altitudinal zone in a highland-fringe area of Ethiopia. Most of the malaria infections were attributable to Plasmodium vivax.

  9. Analysis of Regionally Detected Icequakes Using the STEEP Network, South-Central AK

    Science.gov (United States)

    O'Neel, S.; Leblanc, L.; Larsen, C.; Truffer, M.; Hansen, R.; Rupert, N.; Pavlis, G.; None, N.

    2007-12-01

    Glaciers produce seismic energy that is detectable from local to teleseismic distances. Glaciolgical processes including calving, surface crevassing, basal sliding and other, yet unresolved source processes are capable of producing recordable seismicity. Twenty-two broadband sensors deployed in south-central Alaska during the SainT Elias TEctonics and Erosion Project (STEEP) provide an excellent means to study glacier-generated seismicity at regional distances. These instruments surround over 7500 km2 of glacier area including the Bering Glacier, Bagley Icefield and the tidewater calving glaciers of Icy Bay (Yahtse, Guyot, Tyndal). Our analysis shows that icequakes nominally occur several times hourly, and can be separated from tectonic seismicity using their unique spectral characteristics and hypocenter locations. The events typically propagate over 50-75 km distances, but occasionally are recorded at stations over 150 km away from the energy source. Hypocenters for more than 1000 events were manually calculated through a 26-day interval during October 2006, and suggest that a majority of the icequakes are associated with calving at tidewater glaciers that terminate in Icy Bay. Events with similar time and frequency domain characteristics also occur at locations away from calving fronts, but less often, and their mechanical origin remains undetermined. Automated detections from a frequency domain event detector exhibit strong correlation with the handpicked time series, and extend our analysis to all available data collected during 2006. We present the time distribution of several categories of icequakes and compare these distributions to environmental variables such as precipitation, temperature and tides to explore potential forcing for observed variability in icequake occurrence.

  10. Groundwater chemistry and arsenic mobilization in the Holocene flood plains in south-central Bangladesh.

    Science.gov (United States)

    Bhattacharya, Prosun; Hasan, M Aziz; Sracek, Ondra; Smith, Euan; Ahmed, K Matin; von Brömssen, Mattias; Huq, S M Imamul; Naidu, Ravi

    2009-04-01

    A comparative study of arsenic enrichment in the Bengal Delta (BD) was carried out in three alluvial aquifers in south-central Bangladesh. Investigated sites included Sonargaon in Narayanganj, Chandina in Comilla and Sirajdikhan in Munshiganj districts. At all sites samples from different depths were collected, and water chemistry and redox status vs. depth trends were determined. The concentrations of DOC and HCO(3)(-) were highest at Sirajdikhan site, while at the Sonargaon and Chandina sites the concentrations were lower. On the contrary, the NH(4)(+) concentration was high at the Chandina site as compared to the other sites. There was a good match between dissolved As and Fe at the Sirajdikhan and Sonargaon sites, but not at the Chandina site. The dissolved aqueous concentration of Mn was low at the Chandina site, which suggested that the Mn(IV) redox buffering step was missing. Speciation modeling indicated a possibility of siderite precipitation at all sites, but precipitation of rhodochrosite only at the Sonargaon and Sirajdikhan sites. At the Sirajdikhan site, the log P(CO2) values were very high (-1.37), which revealed the production of CO(2) in redox processes. Principal component analysis (PCA) indicated an impact of sea water and redox status of different samples. These results suggest that the dissolved As is de-coupled from dissolved Mn because when released, As is re-adsorbed onto the Fe(III) minerals in solid phase, as well as from dissolved Fe when precipitation of Fe(II) minerals controls the aqueous concentrations of Fe. In addition, several other concurrent redox processes may exert kinetic constraints depending on refractory characteristics of Fe(III) minerals. PMID:19125338

  11. Risk across disciplines: An interdisciplinary examination of water and drought risk in South-Central Oklahoma

    Science.gov (United States)

    Lazrus, H.; Paimazumder, D.; Towler, E.; McPherson, R. A.

    2013-12-01

    Drought is a challenge faced by communities across the United States, exacerbated by growing demands on water resources and climate variability and change. The Arbuckle-Simpson Aquifer (ASA) in south-central Oklahoma, situated in the heart of the Chickasaw Nation, is the state's only sole-source groundwater basin and sustains the Blue River, the state's only free-flowing river. The recent comprehensive hydrological studies of the aquifer indicate the need for sustainable management of the amount of water extracted. However, the question of how to deal with that management in the face of increasing drought vulnerability, diverse demands, and climate variability and change remains. Water management carries a further imperative to be inclusive of tribal and non-tribal interests. To examine this question, we are conducting an investigation of drought risk from multiple disciplines. Anthropological data comes from stakeholder interviews that were designed to investigate conflict over water management by understanding how people perceive risk differently based on different opinions about the structure of the resource, varying levels of trust in authorities, and unequal access to resources. . The Cultural Theory of Risk is used to explain how people view risks as part of their worldviews and why people who hold different worldviews disagree about risks associated with water availability. Meteorological analyses of longitudinal data indicate periods of drought that are noted in stakeholder interviews. Analysis of stream gauge data investigates the influence of climate variability on local hydrologic impacts, such as changing groundwater levels and streamflows, that are relevant to planning and management decisions in the ASA. Quantitative assessment of future drought risk and associated uncertainty and their effect on type and scale of future economic and social impacts are achieved by combining elements of statistical and dynamical downscaling to improve predictions of

  12. Land subsidence and earth fissures in south-central and southern Arizona, USA

    Science.gov (United States)

    Conway, Brian D.

    2016-05-01

    Land subsidence due to groundwater overdraft has been an ongoing problem in south-central and southern Arizona (USA) since the 1940s. The first earth fissure attributed to excessive groundwater withdrawal was discovered in the early 1950s near Picacho. In some areas of the state, groundwater-level declines of more than 150 m have resulted in extensive land subsidence and earth fissuring. Land subsidence in excess of 5.7 m has been documented in both western metropolitan Phoenix and Eloy. The Arizona Department of Water Resources (ADWR) has been monitoring land subsidence since 2002 using interferometric synthetic aperture radar (InSAR) and since 1998 using a global navigation satellite system (GNSS). The ADWR InSAR program has identified more than 25 individual land subsidence features that cover an area of more than 7,300 km2. Using InSAR data in conjunction with groundwater-level datasets, ADWR is able to monitor land subsidence areas as well as identify areas that may require additional monitoring. One area of particular concern is the Willcox groundwater basin in southeastern Arizona, which is the focus of this paper. The area is experiencing rapid groundwater declines, as much as 32.1 m during 2005-2014 (the largest land subsidence rate in Arizona State—up to 12 cm/year), and a large number of earth fissures. The declining groundwater levels in Arizona are a challenge for both future groundwater availability and mitigating land subsidence associated with these declines. ADWR's InSAR program will continue to be a critical tool for monitoring land subsidence due to excessive groundwater withdrawal.

  13. The effect of heat and smoke on the emergence of exotic and native seedlings in a Mediterranean fire-free matorral of central Chile Efecto del calor y el humo sobre la emergencia de plántulas exóticas y nativas en un matorral mediterráneo libre de fuego en Chile central

    Directory of Open Access Journals (Sweden)

    JAVIER A FIGUEROA

    2012-03-01

    Full Text Available We studied the effect of heat shock and wood-fueled smoke on the emergence of native and exotic plant species in soil samples obtained in an evergreen matorral of central Chile that has been free of fire for decades. It is located on the eastern foothills of the Andes Range in San Carlos de Apoquindo. Immediately after collection samples were dried and stored under laboratory conditions. For each two transect, ten samples were randomly chosen, and one of the following treatments was applied: (1 heat-shock treatment, (2 plant-produced smoke treatment, (3 combined heat-and-smoke treatment, and (4 control, corresponding to samples not subjected to treatment. Twenty-seven species, representing 13 families, emerged from the soil samples. The most abundant families were Asteraceae and Poaceae. All of the emerged species were herbaceous, and 18 species were exotic. Respect to general hypothesis, there is no evidence for the proposition that fire-free matorral has lower proportion of exotic and native species with fire-related cues than matorral with fires. Among the exotic and native, the mean number of species that emerged from soil samples did not change significantly with respect to the control for any of the treatments applied. Nevertheless, important species-specific responses were observed. Smoke and heat-smoke combination significantly increased the emergence of the exotic species Anthriscus caucalis. While smoke-related cues significantly increased the emergence of the exotic species Avena barbata, the emergence of the exotic Aphanes arvensis and the native Bromus berteroanus decreases. For several species our results showed inconsistent responses to fire-related cues compared to those reported in the literature. We suggest that these differences might be related with the fire-history in the populations, an important issue poorly acknowledge in the literature.Nosotros estudiamos el efecto del golpe de calor y del humo de la combustión de

  14. Evaluating the regional influence of Santiago de Chile on air quality and meteorology during VOCALS-REX

    Science.gov (United States)

    Mena, M.; Carmichael, G. R.; Molina, L. T.; Spak, S.; Campos, T.; Mc Naughton, C.; Clarke, A.; Gallardo, L.

    2009-04-01

    The VOCALS campaign was carried out in Chile during October-November 2008, gathering hundreds of scientists from all over the world with the objective to study stratocumulus decks in the East South Pacific, off the coast of Chile and Peru. Surface and airborne platforms measured multiple chemical and meteorological parameters, with support from chemical weather forecast models. Anthropogenic influence on meteorology and climate was evidenced due to in situ measurements, and satellite observations, as was expected from the large point sources of sulfur due to smelters and power plants in the region. However certain conditions benefited long range transport from central Chile, which made the Santiago plume clearly discernible (high ozone, organic aerosol, low CO) as sampled by the NSF C-130 almost 2000 km north of the city. This research will highlight how model products can provide guidance on the sources of the air masses sampled during the campaign, and how the Santiago plume influences regional air quality and meteorology (focusing on effective cloud radii and brightness temperature differences satellite measurements). Ultimately the research shows that the campaign's objective of contrasting cloud properties between pristine and anthropogenically influenced airmasses provided a unique opportunity to isolate the signal of a large emerging South American megacity from remote regions of the East South Pacific.

  15. A river based stable isotope record of orographic precipitation: Taurus Mountains, south central Turkey

    Science.gov (United States)

    Schemmel, Fabian; Mulch, Andreas; Mikes, Tamás.; Schildgen, Taylor

    2010-05-01

    Reconstructing continental precipitation and vegetation patterns has become one of the most rapidly growing fields in terrestrial paleoclimate research. Furthermore, stable isotopes in precipitation within continental plateau regions represent an increasingly important tool for reconstructing the various effects of uplift related climate change within the world's largest plateau regions. With peak elevations of more than 3,000 m the Taurus Mountains represent the southern margin of the central Anatolian plateau and must have played a pivotal role in controlling the drainage and sedimentation patterns within the plateau interior. However, their surface uplift history remains largely elusive. We sampled a series of tributaries and rivers along the Ermenek valley that crosscuts the Taurus Mountains in Southern Turkey. The aim of this study is to quantify the modern effect of orographic rainout of the Taurus Mountains on the d18O and dD values of river and spring waters and to compare these values to the d18O and dD of recent precipitation gathered by the Global Network of Isotopes in Precipitation (GNIP). Further we try to study the trends of the recent d18O and dD isotopic composition of local rivers and precipitation in the area to create a set of isotopic data that is comparable to isotopic studies on paleosoils and can therefore be used in future paleoaltimetry and paleoclimate studies. We sampled 6 individual rivers during the fall season 2008 to capture mostly groundwater runoff in the south central Taurus Mountains. All sampled rivers belong to the same local drainage system which drains into the Mediterranean Sea. The total elevation difference within the sampling area exceeds 2,000 m and we were able to collect samples over almost 1,800 m of elevation. Our measurements show that both d18O and dD values follow the same basic trend. d18O and dD values decrease systematically with increasing elevation. The lapse rate of d18O is about -2.2 per mil/km, whereas the

  16. Paleozoic-involving thrust array in the central Sierras Interiores (South Pyrenean Zone, Central Pyrenees): regional implications

    Science.gov (United States)

    Rodriguez, L.; Cuevas, J.; Tubía, J. M.

    2012-04-01

    This work deals with the structural evolution of the Sierras Interiores between the Tena and Aragon valleys. The Sierras Interiores is a WNW-trending mountain range that bounds the South Pyrenean Zone to the north and that is characterized by a thrust-fold system with a strong lithological control that places preferably decollements in Triassic evaporites. In the studied area of the Sierras Interiores Cenomanian limestones cover discordantly the Paleozoic rocks of the Axial Zone because there is a stratigraphic lacuna developed from Triassic to Late Cretaceous times. A simple lithostratigraphy of the study area is made up of Late Cenomanian to Early Campanian limestones with grey colour and massive aspect in landscape (170 m, Lower calcareous section), Campanian to Maastrichtian brown coloured sandstones (400-600 m, Marboré sandstones) and, finally, Paleocene light-coloured massive limestones (130-230 m), that often generate the higher topographic levels of the Sierras Interiores due to their greater resistance to erosion. Above the sedimentary sequence of the Sierras Interiores, the Jaca Basin flysch succession crops out discordantly. Based on a detailed mapping of the studied area of the Sierras Interiores, together with well and structural data of the Jaca Basin (Lanaja, 1987; Rodríguez and Cuevas, 2008) we have constructed a 12 km long NS cross section, approximately parallel to the movement direction deduced for this region (Rodríguez et al., 2011). The main structure is a thrust array made up of at least four Paleozoic-involving thrusts (the deeper thrust system) of similar thickness in a probably piggyback sequence, some of which are blind thrusts that generate fold-propagation-folds in upper levels. The higher thrust of the thrust array crops out duplicating the lower calcareous section all over the Sierras Interiores. The emplacement of the deeper thrust system generated the tightness of previous structures: south directed piggyback duplexes (the upper

  17. La dieta y fauna de endoparásitos del pejesapo Gobiesox marmoratus Jenyns, 1842 (Pisces: Gobiesocidae en el litoral central de Chile están conectadas pero no correlacionadas Feeding habits and endoparasite fauna of the clingfish Gobiesox marmoratus Jenyns, 1842 (Pisces: Gobiesocidae on the central coast of Chile are intertwined, but not correlated

    Directory of Open Access Journals (Sweden)

    M. Cecilia Pardo-Gandarillas

    2004-12-01

    similarity is documented in the composition of the endoparasitic fauna and the diet of the clingfish G. marmoratus Jenyns, 1842, between three localities off the central coast of Chile separated about 400 km from their nearest neighbor(s. Clingfish in the samples were similar between localities in total body length. The parasite fauna was composed by 16 metazoan taxa (including five Myxozoa. Parasites were found in 38.8 % of the 108 clingfish examined, whereas 32.4 % of the fish in the samples had stomach contents, where 37 prey items were recognized. The even rarer cases of co-occurrence of parasites and prey impeded the search of correlations between both type of variables, such as that between the dietary width and parasite richness. Composition of parasite infracommunities and diet changed along host ontogeny. The diet of juvenile and adult clingfish consisted mainly of amphipods, decapod crustaceans and mollusks at the three localities. The numerical descriptors of the diet and of infracommunities (total abundance, diversity and richness are similar between the localities and along the host ontogeny. The composition of the endoparasitic fauna necessarily depends on the diet of the clingfish, but there is no statistical correlation between both variables. This can be due to the small maximum body size reached by the adults, to the short length of the digestive tract, to the differences in the rate and frequency at which parasites and prey enter and stay in the hosts, to the level of taxonomic resolution attained in prey and/or parasites, and to having decided to include or not rare prey/parasites in the analyses

  18. Cambios latitudinales en la pesquería pelágica de merluza de cola (Macruronus magellanicus de la zona centro-sur (1986-2003 Latitudinal changes in the Patagonian grenadier (Macruronus magellanicus pelagic fishery off central-southern Chile (1986-2003

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    Luis A Cubillos

    2009-01-01

    Full Text Available Se analizaron los cambios espacio-temporales de las capturas de merluza de cola obtenidas por la flota industrial de cerco en la zona centro-sur de Chile (34°-41°30'S, para revisar la hipótesis de migración hacia el norte de la fracción juvenil de merluza de cola en primavera. Se utilizaron datos de bitácoras de pesca del periodo 1986-2003, y a partir de éstos se calcularon centros de gravedad de las capturas y su varianza. Se postula que si la flota sigue el comportamiento migratorio de la fracción juvenil, se esperaría que los centros de gravedad de las capturas migren latitudinalmente de sur a norte conforme la estación de pesca avanza. No obstante, sólo se encontró cuatro casos en que ocurrió una migración hacia el norte de los centroides. Más bien, los centros de gravedad se presentan estacionarios, al interior de cada temporada de pesca. Se postula que existe una fracción juvenil residente que sólo incrementa su accesibilidad y vulnerabilidad en aguas superficiales en primavera debido al régimen ambiental, que se caracteriza por la dominancia de eventos de surgencia y no a una migración de sur a norte.We analyzed spatio-temporal changes in Patagonian grenadier catches by the purse-seine fleet off central-southern Chile (34°-41°30'S in order to check the hypothesis that the juvenile fraction of the population migrates northward in spring. Log-book data from 1986 to 2003 were used to calculate the center of gravity of and variance of each catch. We proposed that, if the fleet follows the migratory behavior of the juvenile fraction, the centers of gravity of the catches will migrate from south to north as the fishing season progresses. Nevertheless, the centers of gravity migrated northward in only four cases. Unexpectedly, the centers of gravity remained stationary within each fishing season. Now we propose that, in spring, a resident juvenile fraction of Patagonian grenadier increases its accessibility and vulnerability

  19. Clasificación acústica de anchoveta (Engraulis ringens y sardina común (Strangomera bentincki mediante máquinas de vectores soporte en la zona centro-sur de Chile: efecto de la calibración de los parámetros en la matriz de confusión Acoustic classification of anchovy (Engraulis ringens and sardine (Strangomera bentincki using support vector machines in central-southern Chile: effect of parameter calibration on the confusion matrix

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    Hugo Robotham

    2012-03-01

    Full Text Available Se clasificó la anchoveta (Engraulis ringens y sardina común (Strangomera bentincki detectadas mediante equipos acústicos en la zona centro-sur de Chile, mediante el método de Máquinas de Vectores Soporte (SVM. Para esto se utilizaron descriptores de cardúmenes extraídos desde ecogramas, que fueron clasificados como morfológicos, batimétricos, energéticos y posicional espacial. Para lograr clasificaciones precisas mediante la utilización de esta metodología, fue necesario optimizar parámetros correspondientes al Kernel-Gaussiano, γ y de penalización del modelo C, mediante el análisis del efecto de la calibración sobre las matrices de confusión resultantes de la clasificación de las especies analizadas. El método SVM ajustó correctamente el 95,3% de los cardúmenes de anchoveta y sardina común. Los parámetros óptimos del Kernel-Gaussiano γ y de penalización C obtenidos mediante la metodología propuesta fueron γ = 450 y C = 0,95, respectivamente. Los parámetros mencionados incidieron de manera importante en la matriz de confusión y los porcentajes de clasificación final, por lo que se sugiere establecer, en aplicaciones futuras de este método, un protocolo experimental de calibración. La sardina común fue la especie con menor error de clasificación en el conjunto de las matrices de confusión. El descriptor correspondiente a profundidad del fondo fue el más sensible al SVM, la segunda variable en importancia es el descriptor distancia a la costa.The support vector machines (SVM method was used to classify the anchovy (Engraulis ringens and common sardine (Strangomera bentincki species detected in south-central Chile by means of acoustic equipment. For this, descriptors of fish schools (morphology, bathymetry, energy, spatial position extracted from ecograms were used. In order to obtain precise classifications using this methodology, it was necessary to optimize the parameters Gaussian-Kernel γ and penalty term

  20. Characterization of surface-water quality based on real-time monitoring and regression analysis, Quivira National Wildlife Refuge, south-central Kansas, December 1998 through June 2001

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Because of the considerable wildlife benefits offered by the Quivira National Wildlife Refuge in south-central Kansas, there is a desire to ensure suitable water...

  1. Archive of Datasonics SIS-1000 Chirp Subbottom Data Collected During USGS Cruise MGNM 00014, Central South Carolina, 13-30 March 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This CD-ROM contains digital high resolution seismic reflection data collected during the USGS MGNM 00014 cruise. The coverage is the nearshore of central South...

  2. Potential role of environmental contaminants in the pathology of beak deformities among Black-capped chickadees in South-central Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — More than 1,400 individual Black-capped Chickadees (Poecile atricapillus) with beak deformities were recorded in south-central Alaska between 1991 and 2005. Over...

  3. Análisis operacional de dos flotas industriales en la pesquería de merluza común (Merluccius gayi gayi, región centro-sur de Chile Operational analysis of two industrial fleet in the Chilean hake (Merluccius gayi gayi fishery in the southern-central region of Chile

    Directory of Open Access Journals (Sweden)

    Catterina Sobenes V.

    2005-11-01

    Full Text Available El trabajo tiene como objetivo analizar la actividad de dos flotas industriales (empresa A y empresa B que operan sobre la pesquería de merluza común en la región centro-sur de Chile. Para ello, se utilizó información histórica de la operación de la flota pesquera entre 1998 y 2002. Se evaluaron las zonas de pesca o caladeros según indicadores de efectividad, costo unitario, rentabilidad y utilidad. Las embarcaciones se seleccionaron acorde a indicadores de eficiencia operacional. Estos resultados fueron contrastados con los caladeros visitados y las embarcaciones utilizadas por las empresas, durante el período de estudio. La zona de pesca más adecuada, se determinó según los índices de eficiencia para 13 caladeros de la región centro-sur de Chile. Se observa que ambas empresas han seleccionado adecuadamente los caladeros Tomé al oeste (caladero 9, Tomé al este (caladero 8 y al sur de Punta Lavapié (caladero 10, que tienen los mejores índices de eficiencia. Respecto a la selección de la embarcación más adecuada, se efectuó un análisis de jerarquización de las embarcaciones, por cada empresa, mediante el análisis de anomalías de indicadores de eficiencia. Ambas empresas seleccionaron aquellas embarcaciones que obtuvieron los mejores indicadores de eficiencia. Para el caladero 9 el estudio propone que la empresa A opere con el pesquero de alta mar PAMa3 y la empresa B con el PAMb4. Sin embargo, en el caladero 10, la empresa A debe utilizar el PAMa5 y no el PAMa3 utilizado históricamente, y la empresa B debe continuar operando con el PAMb1 y PAMb2 como lo ha hecho durante el periodo analizadoThis work aims at analysing the operation of two industrial fishing fleets (company A and company B which works on the Chilean hake (Meluccis gayi gayi fishery in the southern-central region of Chile. For this reason, it was used the historical information of the fleet operation from the southern-central region from 1998 to 2002. The

  4. Historical and projected climate (1901–2050) and hydrologic response of karst aquifers, and species vulnerability in south-central Texas and western South Dakota

    Science.gov (United States)

    Stamm, John F.; Poteet, Mary F.; Symstad, Amy J.; Musgrove, MaryLynn; Long, Andrew J.; Mahler, Barbara J.; Norton, Parker A.

    2014-01-01

    Two karst aquifers, the Edwards aquifer in the Balcones Escarpment region of south-central Texas and the Madison aquifer in the Black Hills of western South Dakota, were evaluated for hydrologic response to projected climate change through 2050. Edwards aquifer sites include Barton Springs, the Bexar County Index Well, and Comal Springs. Madison aquifer sites include Spearfish Creek and Rhoads Fork Spring. Climate projections at sites were based on output from the Community Climate System Model of global climate, linked to the Weather Research and Forecasting (WRF) model of regional climate. The WRF model output was bias adjusted to match means for 1981–2010 from records at weather stations near Madison and Edwards aquifer sites, including Boerne, Texas, and Custer and Lead, South Dakota. Hydrologic response at spring and well sites was based on the Rainfall-Response Aquifer and Watershed Flow (RRAWFLOW) model. The WRF model climate projections for 2011–50 indicate a significant upward trend in annual air temperature for all three weather stations and a significant downward trend in annual precipitation for the Boerne weather station. Annual springflow simulated by the RRAWFLOW model had a significant downward trend for Edwards aquifer sites and no trend for Madison aquifer sites.

  5. Effects of projected climate (2011–50) on karst hydrology and species vulnerability—Edwards aquifer, south-central Texas, and Madison aquifer, western South Dakota

    Science.gov (United States)

    Mahler, Barbara J.; Stamm, John F.; Poteet, Mary F.; Symstad, Amy J.; Musgrove, MaryLynn; Long, Andrew J.; Norton, Parker A.

    2014-01-01

    Karst aquifers—formed by the dissolution of soluble rocks such as limestone—are critical groundwater resources in North America, and karst springs, caves, and streams provide habitat for unique flora and fauna. Springflow and groundwater levels in karst terrane can change greatly over short time scales, and therefore are likely to respond rapidly to climate change. How might the biological communities and ecosystems associated with karst respond to climate change and accompanying changes in groundwater levels and springflow? Sites in two central U.S. regions—the Balcones Escarpment of south-central Texas and the Black Hills of western South Dakota (fig. 1)—were selected to study climate change and its potential effects on the local karst hydrology and ecosystem. The ecosystems associated with the Edwards aquifer (Balcones Escarpment region) and Madison aquifer (Black Hills region) support federally listed endangered and threatened species and numerous State-listed species of concern, including amphibians, birds, insects, and plants. Full results are provided in Stamm and others (2014), and are summarized in this fact sheet.

  6. Meteoric fluids in the South Tibetan Detachment and palaeoaltimetry of Central Himalaya

    Science.gov (United States)

    Gébelin, Aude; Mulch, Andreas; Teyssier, Christian; Jessup, Micah J.; Brunel, Maurice; Cosca, Michael A.; Law, Rick D.

    2015-04-01

    The South Tibetan Detachment (STD) is one of the most fundamental structures within the Himalayan orogenic belt. It exposes a mylonite zone over a distance of > 1500 km along strike that is hundreds of metres thick and separates Paleozoic sedimentary units from high-grade metamorphic rocks and syntectonic leucogranites. In this study, we document the infiltration of meteoric fluids in the STD footwall at ~15 Ma when recrystallized hydrous minerals equilibrated with evolved meteoric water and therefore recorded the hydrogen isotope composition of water present during mylonitic deformation. Although these minerals deformed and recrystallized at significant depth (~10 km), they can be used as palaeoelevation proxies if they can be temporally and kinematically linked to the evolution of the STD. Stable isotope palaeoaltimetry uses the systematic relationship between the oxygen (d18O) and hydrogen (dD) isotope ratios of rainfall that scale with elevation in a predictable fashion (~2.8 per mil in d18O or ~22 per mil in dD per km). Here, we present palaeoaltimetry estimates based on the hydrogen isotope composition of synkinematic micas and amphiboles collected over 200 m of structural section from the STD into the underlying mylonitic footwall at Rongbuk Valley (Mount Everest region). Biotites reveal a very constant pattern of mid-Miocene 40Ar/39Ar plateau ages and exchanged isotopically at high temperature with D-depleted water (dDwater ~ -150 ±5 per mil) that originated from high-elevation precipitation and infiltrated the crustal hydrologic system at that time. To eliminate a climate impact on our palaeoelevation estimates, the hydrogen isotope record from the high elevation STD is compared to time-equivalent low-elevation foreland d18O records. Our palaeoaltimetry results indicate that the mean elevation of Mount Everest region during the mid-Miocene was similar to today (~5200 m). This has two main implications: (1) Strengthening of the Asian Summer Monsoon may

  7. Abundance and dynamics of anopheline larvae in a highland malarious area of south-central Ethiopia

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    Animut Abebe

    2012-06-01

    Full Text Available Abstract Background Malaria is a public health problem in Ethiopia, and increasingly so in highland areas, possibly because of global warming. This study describes the distribution, breeding habitat and monthly dynamics of anopheline larvae in Butajira, a highland area in south-central Ethiopia. Methods A study of the abundance and dynamics of Anopheles larvae was undertaken at different sites and altitudes in Butajira from July 2008 to June 2010. The sites included Hobe (1817 m.a.s.l, Dirama (1995m.a.s.l. and Wurib (2196m.a.s.l.. Potential anopheline larval habitats were surveyed once per month in each village. The recorded characteristics of the habitats included habitat type, pH, surface debris, emergent plants, algae, substrate, turbidity, temperature, length, width, depth, distance to the nearest house and anophelines. The Spearman correlation coefficient and Mann–Whitney U test were used to calculate the degree of association between the density of anopheline species and key environmental factors. Results Among the different types of habitat surveyed, the Odamo, Akamuja and Assas streams and Beko swamp were positive for anopheline larvae. A total of 3,957 third and fourth instar larvae were collected from the three localities, and they represented ten species of anophelines. These were: Anopheles cinereus (32.5%, An. arabiensis (31.4%, An. chrysti (23%, An. demeilloni (12.2%, An. pretoriensis (0.6%, An. azaniae (0.1%, An. rufipes(0.1%, An. sergentii (0.06%, An. garnhami (0.06% and An. pharoensis (0.03%. The density of anopheline larvae was highest during the dry months. An. arabiensis was widely distributed, and its density decreased from the lowest elevation in Hobe to the highest in Wurib. The density of An. arabiensis larvae was correlated positively with larval habitat temperature (r = 0.33, p p  Conclusion Ten species of anophelines were identified, including two known vectors of malaria (An. arabiensis and An. pharoensis

  8. Sedimentary imprints of tsunami and storm deposits on the Shizuoka coastline, south central Japan

    Science.gov (United States)

    Garrett, Ed; Heyvaert, Vanessa M. A.; Fujiwara, Osamu; Brückner, Helmut; Yokoyama, Yusuke; Riedesel, Svenja; Miyairi, Yosuke; Shishikura, Masanobu; De Batist, Marc

    2016-04-01

    Differentiating between the deposits left by extreme wave events - including tsunamis and storms - presents a major challenge for the palaeotsunami and palaeotempestology communities. The coast of Shizuoka Prefecture, south central Japan, is impacted by typhoons and by tsunamis triggered by great subduction zone earthquakes along the adjacent Nankai Trough. A low-lying organic swale close to the town of Shirasuka is well-placed to preserve sedimentary layers left by both event types. The swale lies between a 5 to 10 metre high beach ridge and a 60 to 80 m high riser of the mid-Pleistocene Tenpakubara marine terrace. Investigating the stratigraphy and sedimentology of the site, Komatsubara et al. (2008) identified seven sand layers and attributed these to four tsunamis and one storm, with two sand layers identified as of terrestrial origin. Revisiting the site, we adopted a multi-proxy approach to further analyse the characteristics of selected deposits. We visualise the stratigraphy of retrieved vibrocores in 2D with linescan photography and in 3D with X-ray computed tomography. While problems remain in attempting to fully correlate all sedimentary layers with the published stratigraphy, we suggest that this reflects the difficulties of using a vibrocoring system in an environment characterised by alternating units of unconsolidated sand and compressible humic mud. Nevertheless, by focussing on sand units that are entirely contained within single core sections and by applying Bayesian age models based on new radiocarbon dates, we are able to identify and correlate selected sand layers. Radiocarbon ages, derived from terrestrial plant macrofossils and the acid-insoluble organic fraction of bulk samples sieved to <180 μm, constrain the timing of sand sheet emplacement, facilitating correlation with the historical record. We combine X-ray diffraction, geophysical characterisation and particle size analysis to provide a comprehensive assessment of the variations

  9. Chemical evolution and estimated flow velocity of water in the Trinity Aquifer, south-central Texas

    Science.gov (United States)

    Jones, Sonya A.; Lee, Roger W.; Busby, John F.

    1997-01-01

    Three permeable zones with varying lithology and water chemistry compose the Trinity aquifer, a principal source of water in the 5,500-square-mile study area in south-central Texas. The upper permeable zone locally yields small quantities of water to wells and was not included in this study. The middle permeable zone primarily is composed of limestone with minor amounts of dolostone. Terrigenous sand and marine limestone, with minor amounts of dolostone, are the principal lithologic units in the lower permeable zone. Dissolved solids concentrations range from 329 to 1,820 milligrams per liter in water samples from the middle permeable zone and from 518 to 3,030 milligrams per liter in water samples from the lower permeable zone. Principal hydrochemical facies in the middle permeable zone are calcium magnesium bicarbonate and calcium magnesium sulfate. Hydrochemical facies in ground-water samples from the lower permeable zone vary. Tritium concentrations as large as 5.3 tritium units in the southeastern part of the study area are indicative of relatively recent recharge. Results of a geochemical mass balance simulation along a flowpath in the middle permeable zone indicate a mass transfer of 4.25 millimoles per liter of dolomite dissolved, 5.74 millimoles per liter of gypsum dissolved, 0.46 millimole per liter of sodium chloride dissolved, 8.07 millimoles per liter of calcite precipitated, and 0.67 millimole per liter of calcium-for-sodium cation exchange between solid and aqueous phases. These results support dedolomitization as a principal chemical process in the middle permeable zone of the Trinity aquifer. Results of a simulation along a flowpath in the lower permeable zone indicate a mass transfer of 0.41 millimole per liter of dolomite dissolved, 0.001 millimole per liter of gypsum dissolved, 9.58 millimoles per liter of sodium chloride dissolved, 1.09 millimoles per liter of calcite precipitated, and 1.11 millimoles per liter of sodium-for-calcium cation

  10. Concentration and dry deposition of mercury species in arid south central New Mexico (2001-2002).

    Science.gov (United States)

    Caldwell, Colleen A; Swartzendruber, Philip; Prestbo, Eric

    2006-12-15

    This research was initiated to characterize atmospheric deposition of reactive gaseous mercury (RGM), particulate mercury (HgP; <2.5 microm), and gaseous elemental mercury (Hg0) in the arid lands of south central New Mexico. Two methods were field-tested to estimate dry deposition of three mercury species. A manual speciation sampling train consisting of a KCl-coated denuder, 2.5 microm quartz fiber filters, and gold-coated quartz traps and an ion-exchange membrane (as a passive surrogate surface) were deployed concurrently over 24-h intervals for an entire year. The mean 24-h atmospheric concentration for RGM was 6.8 pg m(-3) with an estimated deposition of 0.10 ng m(-2) h(-1). The estimated deposition of mercury to the passive surrogate surface was much greater (4.0 ng m(-2) h(-1)) but demonstrated a diurnal pattern with elevated deposition from late afternoon to late evening (1400-2200; 8.0 ng m(-2) h(-1)) and lowest deposition during the night just prior to sunrise (2200-0600; 1.7 ng m(-2) h(-1)). The mean 24-h atmospheric concentrations for HgP and Hg0 were 1.52 pg m(-3) and 1.59 ng m(-3), respectively. Diurnal patterns were observed for RGM with atmospheric levels lowest during the night prior to sunrise (3.8 pg m(-3)) and greater during the afternoon and early evening (8.9 pg m(-3)). Discernible diurnal patterns were not observed for either HgP or Hg0. The total dry deposition of Hg was 5.9 microg m-2 year-' with the contribution from the three species as follows: RGM (0.88 microg m(-2) year(-1)), HgP (0.025 microg m(-2) year(-1)), and Hg0 (5.0 microg m(-2) year(-1)). The annual wet deposition for total mercury throughout the same collection duration was 4.2 microg m(-2) year (-1), resulting in an estimated total deposition of 10.1 microg m(-2) year(-1) for Hg. On one sampling date, enhanced HgP (12 pg m(-3)) was observed due to emissions from a wildfire approximately 250 km to the east. PMID:17256491

  11. Ordovician Intrusive-related Gold-Copper Mineralization in West-Central New South Wales, Australia

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Three major types of Ordovician intrusive-related gold-copper deposits are recognized in central-west New South Wales,, Australia: porphyry, skam and high sulphidation epithermal deposits.These deposits are mainly distributed within two Ordovician volcano-intrusive belts of the Lachlan Fold Be1t: the Orange-Wellington Belt and the Parkes-Narromine Belt. Available isotopic age data suggest that mineralization of the three types of deposits is essentially coeval with the Ordovician intrusive rocks (480-430 Ma). Porphyry gold-copper deposits can be further divided into two groups. The first group is associated with monzoniteshowing shoshonitic features represented by Cadia and Goonumbla. The second group is associated with diorite and dacite, including the Copper Hill and Cargo gold-copper deposits. Gold skarn is associated with Late Ordovician (430-439 Ma) monzonitic intrusive complexes in the Junction Reefs area (Sheahan-Grants, Frenchmans, and Cornishmens), Endeavour 6, 7 and 44, Big and Little Cadia. The epithermal gold deposits with high sulphidation including Gidginbung (Temora) and Peak Hill mainly occur within Ordovician andesite and volcaniclastic rocks, and are associated with advanced argillic alteration. Available isotopic age data indicate that both alteration and mineralization of the porphyry, skam and epithermal gold-copper deposits are broadly coeval with the Late Ordovician hoshonitic mangmatism, which is thought to result from the melting of sub-continental lithosphere caused by Palaeozoic subduction events. The Ordovician intrusive-related gold-copper deposits are restricted to two longitudinal parallel volcano-intrusive belts, rarely extending outside them. Diagonal intra-belt trends of mineralization are common, particularly at the intersections of longitudinal and transverse (oblique) fault/fracture zones basedon the authors'review of available geological data. The locations of these gold-copper deposits are obviously influenced by transverse

  12. Nitrous oxide distribution and its origin in the central and eastern South Pacific Subtropical Gyre

    Directory of Open Access Journals (Sweden)

    J. Charpentier

    2007-05-01

    Full Text Available The biogeochemical mechanism of bacterial N2O production in the ocean has been the subject of many discussions in recent years. New isotopomeric tools can help further knowledge on N2O sources in natural environments. This research shows and compares hydrographic, nitrous oxide concentration, and N2O isotopic and isotopomeric data from three stations across the South Pacific Ocean, from the center of the subtropical oligotrophic gyre (~26° S; 114° W to the upwelling zone along the central Chilean coast (~34° S. Althought AOU/N2O and NO3 trends support the idea that most of N2O source (mainly from intermediate water (200–1000 m come from nitrification, N2O isotopomeric composition (intramolecular distribution of 15N isotopes in N2O reveals an abrupt change in the mechanism of nitrous oxide production, always observed through lower SP (site preference of 15N, at a high – stability layer, where particles could act as microsites and N2O would be produced by nitrifier denitrification (reduction of nitrite to nitrous oxide mediated by primary nitrifiers. There, nitrifier denitrification can account for 40% and 50% (center and east border of the gyre, respectively of the nitrous oxide produced in this specific layer. This process could be associated with the deceleration of sinking organic particles in highly stable layers of the water column. In constrast, coastal upwelling system is characterized by oxygen deficient condition and some N deficit in a eutrophic system. Here, nitrous oxide accumulates up to 480% saturation, and isotopic and isotopomer signal show highly complex nitrous oxide production processes, which presumably reflect both the effect of nitrification and denitrification at low oxygen levels on N2O production, but non N2O consumption by denitrification was observed.

  13. Sources of elevated salinity in the Mississippi River Alluvial Aquifer, south-central Louisiana, USA

    International Nuclear Information System (INIS)

    Highlights: → Salinization is impacting groundwater quality in southern Louisiana, USA. → This includes the Mississippi River Alluvial Aquifer. → Geochemical evidence indicates salt dome dissolution is responsible. → Thus, salinization here is a natural, on-going process. → The potential for remediation is slight, if not non-existent. - Abstract: Salinization is a process impacting groundwater quality and availability across much of southern Louisiana, USA. However, a broad divergence of opinion exists regarding the causes of this elevated salinity: updip-migrating marine waters from the Gulf of Mexico, saline fluids migrating up fault planes, movement of water from salt domes, and/or remnant seawater from the last major marine transgression. The Mississippi River Alluvial Aquifer (MRAA) in south-central Louisiana is recharged by the Mississippi River, and there are discharge zones to the west and east. Recharge waters from the Mississippi River are fresh, but Cl- levels in the western portions of the aquifer are as high as 1000 mg/L. The aquifer is an important source of water for several municipalities and industries, but prior to this study the source(s) of the elevated salinity or whether the salinization can be remediated had not been determined. The low Br/Cl ratios in the groundwaters are consistent with a saline endmember produced by subsurface dissolution of salt domes, not a marine source. The H and O isotopic systematics of the aquifer waters indicate meteoric sources for the H2O, not marine waters or diagenetically-altered deep brines. The westward salinization of aquifer water represents a broad regional process, instead of contamination by point sources. Mapping of spatial variations in salinity has permitted the identification of specific salt domes whose subsurface dissolution is producing waters of elevated salinity in the aquifer. These include the Bayou Choctaw and St. Gabriel domes, and possibly the Bayou Blue dome. Salinization is a

  14. Reconstructing 20th Century Summer Precipitation on the South-Central Tibetan Plateau

    Science.gov (United States)

    Conroy, J. L.; Hudson, A. M.; Overpeck, J. T.; Cole, J. E.; Liu, K.; Wang, L.

    2011-12-01

    The Tibetan Plateau has experienced significant increases in temperature over the 20th century, but trends in precipitation are less clear, as station precipitation records are sparse and satellite observations only extend back to 1979. Here we use the sediment record from Ngamring Co, a closed-basin, freshwater lake in south-central Tibet, to assess summer precipitation over the last century. Ngamring Co is located in a watershed without glaciers, so recent changes in runoff and lake level are independent of the influence of glacial ice volume. The first principal component of the Ngamring Co grain size dataset is highly correlated with median grain size and covaries significantly with local July-August precipitation from the CPC Merged Analysis of Precipitation (CMAP). From 1979 to 2007, median grain size decreases with increasing July-August precipitation and increases with decreasing July-August precipitation. There is prominent multidecadal variability in the 20th century grain size record, including a gradual decline in median grain size from 1900 to 1930, a gradual increase in median grain size from 1930 to 1990, and a rapid decline in median grain size since 1990. Median grain size values from 2000-2007 are the lowest in the 107-year record, suggesting the most abundant monsoon precipitation in the last 107 years has occurred in the last decade. Satellite images of the lake also confirm an increase in lake area since the early 1990s, but also show the greatest lake area occurred in the 1970s. Thus, although summer precipitation and lake area do covary, precipitation does not seem to control grain size by influencing lake area. We presently hypothesize that increased July-August precipitation causes enhanced erosion of the fine-grained sediment (likely paleolake sediments and loess) that blankets the slopes surrounding the lake. The ensuing runoff and deposition of this sediment into the lake then results in a decline in median grain size within the lake

  15. Energy Use and Energy Efficiency in Selected Arable Farms in Central and South Eastern Europe

    Directory of Open Access Journals (Sweden)

    Gerhard Moitzi

    2014-03-01

    Full Text Available The main objective of the project “Mechanization and Energy use in selected arable farms in Central and South Eastern Europe (CASEE” was to analyse energy characteristics of arable farming in Slovak Republic, Romania, Serbia and Austria, to compare results and identify possibilities of its improvements. The large scale farms are: the university farm of the Slovak University of Agriculture (SK with 1.112 ha arable land, a cooperative farm in Risnovice (SK with an arable land of 1.266 ha, a family farm in Apahida-Transylvania (RO with 400 ha, a farm in Viisoara-Transylvania (RO with 600 ha, a family farm in Sremska Mitrovica (SRB with an arable land of 115 ha, a family farm near Novi Sad (SRB with an arable land of 450 ha and a family farm in Ansfelden/Linz (A with 368 ha. The farms were visited by the interviewer once or more times and the relevant data, used machinery, quantity of inputs, e.g. fuel, pesticides, fertilizer, seed and yields of harvested crops, were recorded, for the production season 2012. After collection of the basic data all energy inputs and outputs, energy content of crops, were calculated in accordance with data and procedure defined by CIGR (International Commission of Agricultural and Biosystems Engineering, Handbook Volume V – Energy and Biomass Engineering (1999. Energy input and net energy gain, expressed in MJ/ha, were used to calculate energy characteristics of crops’ production: energy productivity - kg/MJ, energy efficiency index, energy ratio, energy intensity - MJ/kg, fuel intensity - L/kg. The intensity of all used farm inputs (fuel, seeds, fertilizer and pesticide in crop production systems influences the energy efficiency. The fuel consumption for winter wheat production of the analysed farms ranges between 54 and 91 l/ha. The mean energy ratio (energy-output/energy-input for winter wheat is 5.6 with ranges between 4.8 and 7.1. Besides the fuel consumption the energy-input via the nitrogen-fertilizer is

  16. Environmental Factors Affecting the Whale Shark Aggregation site in the South Central Red Sea

    KAUST Repository

    Hozumi, Aya

    2015-12-01

    Motivation behind the spring whale shark (Rhincodon typus) aggregation in Al-Lith, on the Saudi Arabian coast of the South Central Red Sea, is uncertain. A plausible hypothesis is that whale sharks gather to feed on high prey density, leading to questions about the cause of the prey density. A bottom-up process fueled by nutrient input or accumulation from physical advection could create a peak in prey biomass. Wastewater discharged from an aquaculture facility could affect productivity or provide a chemosensory cue for whale sharks. Yet, basic physico-biological oceanography of this region is unresolved. Monthly profiles, long-term moorings, and spatial surveys were used to describe the temporal variability of potential prey biomass and water masses in this region for the first time. Plankton abundance of individuals larger than ~0.7 cm did not peak during whale shark season. Rather, a decrease coinciding the trailing end of whale shark detections was observed. Sites 180 m apart had differences in acoustic backscatter, suggesting small-scale biomass patchiness, supporting the small-scale variability in whale shark habitat selectivity. Red Sea Deep Water, a nutrient-rich water mass formed in the northern Red Sea, appeared in July at the same time the Tokar wind jet from the Sudanese mountain gap is the highest. Gulf of Aden Water, a nutrient-rich water mass from the Indian Ocean, arrived as episodes from May to September, contrary to previous expectations that the water arrives continuously. It is unlikely that these natural nutrient sources are directly responsible for the high prey density attracting the whale sharks. The aquaculture plume, observed at the aggregation site, had a distinct seasonality from the ambient waters. The plume’s highest salinity (>48) approached the extreme limits of coral tolerances. Nutrient concentrations (nitrate, nitrite, phosphate, silica), suspended particulate matter, phytoplankton biomass, bacteria and cyanobacteria cell counts

  17. Channel adjustments to historical disturbances along the lower Brazos and Sabine Rivers, south-central USA

    Science.gov (United States)

    Heitmuller, Franklin T.

    2014-01-01

    Historical channel adjustments are documented and discussed in context with anthropogenic disturbances along two meandering, coastal plain rivers - the lower Brazos and Sabine Rivers in the south-central United States. Hard-copy streamflow-measurement notes of the U.S. Geological Survey were utilized to render historical cross sections (1925-2007) at nine gauging stations, which were complemented with repeat photographs and flood-frequency analysis to assess trajectories of channel change and interpret causative mechanisms. Downstream- and upstream-propagating disturbances caused episodes of channel-bed incision and aggradation at different locations for distinct time periods along both rivers. Incision associated with upstream dams is detected, but channels are compensated downstream with sediment inputs from lateral channel migration and tributaries. In one case, temporary aggradation along the Brazos River at Waco was likely caused by a combination of dam construction and regional soil erosion. Channel-bed incision on the lowermost Brazos River is unrelated to dams, but is associated with instream aggregate extraction, possibly in conjunction with downstream channelization. On the Sabine River, extensive aggradation during the 1930s might be associated with logging activities (1880s-1930s), but whether the cause is pervasive regional-scale hillslope erosion or local-scale mill-site activities is indeterminate. Following passage of this sediment, the river generally recovered to pre-disturbance conditions and has exhibited stability despite a mainstem reservoir. Translation of this sediment slug is attenuated by a transition to a flood-prone, distributary-dominated system downstream of the Holocene-Pleistocene terrace onlap position. Additional findings include cross-channel hingepoints separating thalweg incision from simultaneous point-bar or bank accretion at meander bends, which indicates channel adjustment occurs along non-cohesive beds in preference to

  18. Aeromagnetic interpretation in the south-central Zimbabwe Craton: (reappraisal of) crustal structure and tectonic implications

    Science.gov (United States)

    Ranganai, Rubeni T.; Whaler, Kathryn A.; Ebinger, Cynthia J.

    2015-12-01

    Regional aeromagnetic data from the south-central Zimbabwe Craton have been digitally processed and enhanced for geological and structural mapping and tectonic interpretation integrated with gravity data, to constrain previous interpretations based on tentative geologic maps and provide new information to link these structural features to known tectonic events. The derived maps show excellent correlation between magnetic anomalies and the known geology, and extend lithological and structural mapping to the shallow/near subsurface. In particular, they reveal the presence of discrete crustal domains and several previously unrecognised dykes, faults, and ultramafic intrusions, as well as extensions to others. Five regional structural directions (ENE, NNE, NNW, NW, and WNW) are identified and associated with trends of geological units and cross-cutting structures. The magnetic lineament patterns cut across the >2.7 Ga greenstone belts, which are shown by gravity data to be restricted to the uppermost 10 km of the crust. Therefore, the greenstone belts were an integral part of the lithosphere before much of the upper crustal (brittle) deformation occurred. Significantly, the observed magnetic trends have representatives craton-wide, implying that our interpretation and inferences can be applied to the rest of the craton with confidence. Geological-tectonic correlation suggests that the interpreted regional trends are mainly 2.5 Ga (Great Dyke age) and younger, and relate to tectonic events including the reactivation of the Limpopo Belt at 2.0 Ga and the major regional igneous/dyking events at 1.8-2.0 Ga (Mashonaland), 1.1 Ga (Umkondo), and 180 Ma (Karoo). Thus, their origin is here inferred to be inter- and intra-cratonic collisions and block movements involving the Zimbabwe and Kaapvaal Cratons and the Limpopo Belt, and later lithospheric heating and extension associated with the break-up of Gondwana. The movements produced structures, or reactivated older fractures

  19. Hydrological impact of rainwater harvesting in the Modder river basin of central South Africa

    Directory of Open Access Journals (Sweden)

    W. A. Welderufael

    2011-05-01

    Full Text Available Along the path of water flowing in a river basin are many water-related human interventions that modify the natural systems. Rainwater harvesting is one such intervention that involves harnessing of water in the upstream catchment. Increased water usage at upstream level is an issue of concern for downstream water availability to sustain ecosystem services. The upstream Modder River basin, located in a semi arid region in the central South Africa, is experiencing intermittent meteorological droughts causing water shortages for agriculture, livestock and domestic purpose. To address this problem a technique was developed for small scale farmers with the objective of harnessing rainwater for crop production. However, the hydrological impact of a wider adoption of this technique by farmers has not been well quantified. In this regard, the SWAT hydrological model was used to simulate the hydrological impact of such practices. The scenarios studied were: (1 Baseline scenario, based on the actual land use of 2000, which is dominated by pasture (combination of natural and some improved grass lands (PAST; (2 Partial conversion of Land use 2000 (PAST to conventional agriculture (Agri-CON; and (3 Partial conversion of Land use 2000 (PAST to in-field rainwater harvesting which was aimed at improving the precipitation use efficiency (Agri-IRWH.

    SWAT was calibrated using observed daily mean stream flow data of a sub-catchment (419 km2 in the study area. SWAT performed well in simulating the stream flow giving Nash and Sutcliffe (1970 efficiency index of 0.57 for the monthly stream flow calibration. The simulated water balance results showed that the highest peak mean monthly direct flow was obtained on Agri-CON land use (18 mm, followed by PAST (12 mm and Agri-IRWH land use (9 mm. These were 19 %, 13 % and 11 % of the mean annual rainfall, respectively. The Agri-IRWH scenario reduced direct flow by 38 % compared to Agri-CON. On the other

  20. Sources of elevated salinity in the Mississippi River Alluvial Aquifer, south-central Louisiana, USA

    Energy Technology Data Exchange (ETDEWEB)

    Welch, Stephanie E. [Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803 (United States); Hanor, Jeffrey S., E-mail: hanor@lsu.edu [Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803 (United States)

    2011-08-15

    Highlights: > Salinization is impacting groundwater quality in southern Louisiana, USA. > This includes the Mississippi River Alluvial Aquifer. > Geochemical evidence indicates salt dome dissolution is responsible. > Thus, salinization here is a natural, on-going process. > The potential for remediation is slight, if not non-existent. - Abstract: Salinization is a process impacting groundwater quality and availability across much of southern Louisiana, USA. However, a broad divergence of opinion exists regarding the causes of this elevated salinity: updip-migrating marine waters from the Gulf of Mexico, saline fluids migrating up fault planes, movement of water from salt domes, and/or remnant seawater from the last major marine transgression. The Mississippi River Alluvial Aquifer (MRAA) in south-central Louisiana is recharged by the Mississippi River, and there are discharge zones to the west and east. Recharge waters from the Mississippi River are fresh, but Cl{sup -} levels in the western portions of the aquifer are as high as 1000 mg/L. The aquifer is an important source of water for several municipalities and industries, but prior to this study the source(s) of the elevated salinity or whether the salinization can be remediated had not been determined. The low Br/Cl ratios in the groundwaters are consistent with a saline endmember produced by subsurface dissolution of salt domes, not a marine source. The H and O isotopic systematics of the aquifer waters indicate meteoric sources for the H{sub 2}O, not marine waters or diagenetically-altered deep brines. The westward salinization of aquifer water represents a broad regional process, instead of contamination by point sources. Mapping of spatial variations in salinity has permitted the identification of specific salt domes whose subsurface dissolution is producing waters of elevated salinity in the aquifer. These include the Bayou Choctaw and St. Gabriel domes, and possibly the Bayou Blue dome. Salinization is a

  1. Analyses of Genotypic Diversity among North, South, and Central American Isolates of Sugarcane Yellow Leaf Virus: Evidence for Colombian Origins and for Intraspecific Spatial Phylogenetic Variation

    OpenAIRE

    Moonan, Francis; Mirkov, T. Erik

    2002-01-01

    We have analyzed the genotypic diversity of Sugarcane yellow leaf virus (SCYLV) collected from North, South, and Central America by fingerprinting assays and selective cDNA cloning and sequencing. One group of isolates from Colombia, designated the C-population, has been identified as residing at the root node between a separable superpopulation structure of SCYLV and other members of the family Luteoviridae, indicating that the progenitor viruses of the North, South, and Central American iso...

  2. Rhizosphere Pseudomonas sp. strains reduce occurrence of pre- and post-emergence damping-off in chile and tomato in Central Himalayan region.

    Science.gov (United States)

    Sharma, Alok; Wray, Victor; Johri, Bhavdish N

    2007-04-01

    Based on in vitro screening for PGP and anti-mycelial activity against three zoosporic pathogenic oomycetes, Pythium aphanidermatum 123, P. aphanidermatum 4746, and Phytophthora nicotianae 4747, seven bacterial isolates were selected for field trials on tomato and chile to test for plant growth promotion under natural and artificial disease-infested field sites in both winter and wet seasons. The effectiveness of isolates in the field trials correlated with the in vitro antagonism screening data. Pseudomonas sp. FQP PB-3, FQA PB-3 and GRP(3) showed substantial beneficial effects on plant growth promotion and lowered considerably the incidence of pre- and post-emergence damping-off in both the crops under various disease scenarios. For example, seed bacterization with these bacterial strains reduced pre-emergence-damping off by ca. 60-70% in the two natural sites, with and without histories of fungicide use in the winter season, and to a lesser extent, ca. 20-40%, in the warmer wet (high humidity; 85-92%) season. The suppression efficacy for post-emergence damping-off was less compared to pre-emergence damping-off although still significant (P > 0.05). Our data unambiguously show that screening of a large number of bacterial pool identifies promising isolates that show beneficial effects on all stages of plant growth in natural oomycete-infested regimes. PMID:17160408

  3. Transportation in Developing Countries: Greenhouse Gas Scenarios for Chile

    OpenAIRE

    Raúl O'Ryan; Daniel Sperling; Tom Turrentine; Mark Delucchii

    2001-01-01

    Chile is a lightly populated country of 15 million that has undergone large economic transformations. Over the past 25 years, the economy has evolved from a slow-growing state-directed economy into a fast growing, market-oriented economy. Its South American neighbors are imitating this transformation. The changes have been especially great in the transport sector, with the private sector taking over many traditional public sector activities. This report addresses the implications of Chile's e...

  4. Holocene and deglacial paleoenvironmental history of the Peru-Chile current system and adjacent continental Chile

    Science.gov (United States)

    Lamy, F.; Hebbeln, D.; Kim, J.; Mohtadi, M.; Ruehlemann, C.

    2002-12-01

    A combined analysis of terrigenous and biogenic compounds in marine sediments from the Chilean continental slope allows detailed reconstructions of both the paleoclimatic and paleoceanographic history of this region during the last glacial and Holocene. Based on sediment cores recovered during two cruises with the German R/V Sonne, we found evidence for changes both in continental rainfall, most likely induced by latitudinal shifts of the Southern Westerlies, and marine productivity as well as sea surface temperature (SST) changes within the Peru-Chile Current system on time scales ranging from Milankovitch to centennial-scale. On Milankovitch time-scales, we found strong evidence for precession-controlled shifts of the Southern Westerlies implying e.g. more humid conditions during the LGM in the Chilean Norte Chico and a trend towards more arid climates during the deglaciation culminating in the early Holocene. These shifts are paralleled by paleoceanographic changes indicating generally higher productivity during the LGM mainly caused by increased advection of nutrients from the south through an enhanced Peru-Chile current. SSTs off central Chile were about 3.5 C lower than present during the LGM. On shorter time-scales, extremely high resolution sediment cores from the southern Chilean margin provide evidence of significant short-term Holocene climate changes with bands of variability centred at ca. 900 and 1500 years, periodicities also well known from Northern Hemisphere records. Our data point to strong interhemispheric connections of climate change both on multi-centennial to millennial and Milankovitch time-scales with a major role of the tropics for the interhemispheric transfer of climate signals involving changes within the Hadley circulation and/or probably long-term modifications of the El Ni¤o-Southern Oscillation system. The recently drilled ODP Sites 1233 (ca. 41S) and 1234/1235 (ca. 36S) at the southern Chilean margin have the potential to extent

  5. Determination of potential risk of heat stress of cattle in four locations of Central and Southern Chile Determinación del riesgo potencial de estrés térmico del ganado bovino en cuatro localidades del centro y sur de Chile

    Directory of Open Access Journals (Sweden)

    RA Arias

    2010-01-01

    Full Text Available Meteorological data from December to January of years 1999 to 2007 from weather stations located in four localities in Chile (Curicó, Chillán, Temuco and Osorno were used to calculate the adjusted temperature-humidity index (THIadj-max. Climate variables used to calculate the index were: wind speed, air temperature, relative humidity and an estimated value of solar radiation. When the values of THIadj-max were greater than 75, those days were considered as “alert” and as potential risk of heat stress in cattle. Additionally, the impact of climate on animal production was assessed by means of potential losses in milk production for each locality estimated by two equations. The localities of Curicó and Chillán presented similar values of THIadj-max (79.4 and 79.1, respectively, and both were higher than those for Temuco and Osorno (77.1 and 68.1, respectively, P 75 was greater in the Central region. In addition, the estimated mean milk production loss was greater in the Central regions (1.5 to 4.3 and 1.2 to 3.1 L*cow-1*d-1 for Curicó and Chillán, respectively. Conversely, the Southern regions, Temuco and Osorno, presented lower potential losses with 0.9 to 2.6 and 0.1 to 0.6 L*cow-1*d-1, respectively. In conclusion, the potential risk of heat stress of cattle seems greater in Curicó and Chillán, moderate in Temuco and minimum in Osorno. Additional research is needed in the order to quantify the impacts of environmental conditions in productivity and welfare of cattle in Chile.Datos climáticos del periodo diciembre a febrero de los años 1999 al 2007 provenientes de estaciones meteorológicas situadas en Curicó, Chillán, Temuco y Osorno fueron utilizados para calcular un índice temperatura-humedad ajustado por el efecto del viento y de la radiación (THIadj-max. Las variables climáticas utilizadas para calcular este índice incluyeron: velocidad del viento, temperatura máxima del aire, humedad relativa y un valor estimado de la

  6. Eso's Situation in Chile

    Science.gov (United States)

    1995-02-01

    that the best VLT site would be the Paranal Mountain, 700 km north of La Silla and 130 km south of Antofagasta, the capital of the Second Region in Chile. In October 1988, the Chilean Government by an official act donated the land surrounding Paranal (in all 725 sq. km) to ESO. As is the case for La Silla, this would serve to protect the planned, incredibly sensitive mega-telescope against all possible future sources of outside interference. The donation was made on the condition that ESO would indeed proceed with the construction of the VLT at Paranal within the next five years. The corresponding decision was taken by the ESO Council in December 1990. The construction of the VLT observatory site at Paranal started immediately thereafter, thus fulfilling the condition attached to the donation. The construction of the VLT is now well advanced. In Europe, the main parts of the first VLT unit 8.2-metre telescope will be pre-assembled later this year and the first two of the enormous mirrors are being polished. In Chile, the extensive landscaping of the Paranal peak was finished in 1993, during which around 300,000 cubic metres of rock and soil was removed to provide a 100x100 sq. metres platform for the VLT, and the concrete foundations are now ready. The installation of the first telescope enclosure can now begin and the next will start later this year. The first of the four telescopes is expected to start observations in late 1997. All in all, ESO has until now committed about 70 percent of the expected total investment for the VLT, estimated to be approximately 570 million DEM. THE OWNERSHIP OF PARANAL According to information later received, the Chilean Ministry of National Properties ("Bienes Nacionales") inscribed in 1977 in its name various lands in the commune of Taltal, including the area of the Paranal peak. At that time, i.e. ten years before ESO decided to construct the VLT, nobody in this Organisation could imagine that this telescope would one day be

  7. Caracterización de agregaciones de merluza de cola (Macruronus magellanicus en la zona centro-sur de Chile Characterization of Chilean hoki (Macruronus magellanicus aggregations off central-southern Chile

    Directory of Open Access Journals (Sweden)

    Dante Queirolo

    2008-01-01

    Full Text Available Se realizó la caracterización mensual de las agregaciones de merluza de cola usando registros acústicos obtenidos por equipos SIMRAD EK60 y ES60 a bordo de tres embarcaciones multipropósito que operaron en la Unidad de Pesquería Centro-Sur durante el año 2003, para lo cual se emplearon descriptores morfológicos y batimétricos. En cuanto a su morfología, las agregaciones mostraron una amplia variabilidad, explicada por su nivel de cohesión y tendencia a formar agregaciones de gran extensión horizontal, mientras que batimétricamente se determinó que el 90% de éstas se ubicaron preferentemente entre 300 y 450 m. Existe evidencia de asociación entre diversos descriptores y estos a su vez con otros factores como talla media, temperatura del agua, latitud y mes, lo que permite describir apropiadamente la forma de las agregaciones y su ubicación en la columna de agua. Algunas relaciones relevantes corresponden a: profundidad de las agregaciones respecto a la profundidad del fondo (r = 0,55, altitud de las agregaciones respecto a la profundidad del fondo (r = 0,72, altitud de las agregaciones respecto al índice de profundidad relativa (r = -0,98 y profundidad de las agregaciones respecto a la talla media (r = 0,66.A monthly characterization of Chilean hoki aggregations was done using acoustic records ob-tained with SIMRAD EK60 and ES60 devices aboard three multipurpose vessels that operated in the central-southern fishery unit during 2003; this considered morphological and bathymetric descriptors. The wide mor-phological variation of the aggregations was explained by their cohesión level and tendency to form large horizontal aggregations whereas, bathymetrically, 90% of the aggregations were located between 300 and 450 m. Evidence of associations between various descriptors was found, and these were, in turn, associated with other factors such as mean size, water temperature, latitude, and month, allowing an adequate description of the

  8. A small, new gerbil-mouse Eligmodontia (Rodentia: Cricetidae) from dunes at the coasts and deserts of north-central Chile: molecular, chromosomic, and morphological analyses.

    Science.gov (United States)

    Spotorno, Angel E; Zuleta, Carlos; Walker, Laura I; Manriquez, German; Valladares, Pablo; Marin, Juan C

    2013-01-01

    A small, new species of gerbil rodents of the genus Eligmodontia from the southwestern dunes of the Atacama Desert in northern Chile is described; the genus had not been reported for this western lowland region. Our description is based on cytogenetic and molecular data, as well as cranial and external morphology. In order to support this hypothesis, we studied 27 specimens captured in Playa Los Choros (Coquimbo) and Copiapó (Atacama), comparing them with samples of all the extant species of the genus. Nineteen individuals consistently showed 2N=50, FN=48, with telocentric chromosomes and G-bands identical to those of the geographically northeastern E. hirtipes; these two groups were geographically separated by E. puerulus (2N = 34, FN = 48). The phylogenetic analysis of 56 Eligmodontia cytochrome-b gene sequences yielded a maximum-likelihood phylogenetic tree where the new species formed a divergent and well-supported clade within the genus, which was also confirmed by unweighted parsimony, minimum evolution, and Bayesian analyses. The new species has K2P genetic distances of 12.8% from the geographically distant E. hirtipes, and 10.3% from E. puerulus. Axes 1 and 2 of Principal Component Analysis based on 12 body and skull measurements clearly separated the new species, the latter having a smaller head+body length (70.6 +/- 3.4 mm, n = 17) and lower weight (11.9 +/- 1.9 g, n = 20). We provide strong evidence to recognize a distinct new western lineage within Eligmodontia genus, Eligmodontia dunaris sp. nov., for which we give a complete taxonomic description and a hypothetical biogeographic scenario. The new species should be considered endangered, due to its level of endemism, its low population numbers (which can be occasionally increased after a blooming desert) and its fragile dry habitat patchily distributed near the Atacama Desert. PMID:25250459

  9. Lactose intolerance genetic testing: is it useful as routine screening? Results on 1426 south-central Italy patients.

    Science.gov (United States)

    Santonocito, Concetta; Scapaticci, Margherita; Guarino, Donatella; Annicchiarico, Eleonora Brigida; Lisci, Rosalia; Penitente, Romina; Gasbarrini, Antonio; Zuppi, Cecilia; Capoluongo, Ettore

    2015-01-15

    Adult-type hypolactasia is a widespread condition throughout the world, causing lactose malabsorption. Several studies suggested that the identification of C/T-13910 and G/A-22018 mutations, located upstream the gene encoding the lactase-phlorizin hydrolase (LPH), is a useful tool for the differential diagnosis of hypolactasia. We evaluated the frequencies of C/T-13910 and G/A-22018 variants in a central-south Italian population and the usefulness of lactase deficiency genetic testing in the clinic practice. The genomic DNA of 1426 patients and 1000 healthy controls from central-south Italy was isolated from peripheral whole blood and genotyped for the C/T-13910 and G/A-22018 polymorphisms by high-resolution melting analysis (HRMA) and sequencing. The frequencies of genotypes in the 1426 patients analysed were as follows: 1077 CC/GG (75.5%), 287 CT/GA (20.1%), 24 TT/AA (1.7%), 38 CC/GA (2.7%). Only 64 out of 1426 (4.5%) performed also L-BHT test, 29 of which were negative for L-BHT also in presence of different genotypes. Among the 35 individuals with L-BHT positive, 34 were CC/GG and only one CT/GA. Although lactose genetic test is a good predictor of persistence/non-persistence lactase in specific population, its use in the central-south Italy population should be limited given the high prevalence of the CCGG diplotype in normal individuals. PMID:25281930

  10. Environmental noise and cardiovascular disease in adults: Research in Central, Eastern and South-Eastern Europe and Newly Independent States

    OpenAIRE

    L′ubica Argalášová-Sobotová; Jurgita Lekaviciute; Sonja Jeram; L′udmila Ševcíková; Jana Jurkovicová

    2013-01-01

    The adverse effects of noise on health have been intensely explored in the past 50 years. However, the scope of research conducted in the Central and Eastern Europe, South-East Europe, and Newly Independent States is not well-known. The aim of this review was to present studies on cardiovascular effects of environmental noise in adults published since 1965 and to point out the most important issues that need to be addressed in the future. More than 100 papers on noise and health and about 20 ...

  11. Dutch Disease in the Post-Soviet Countries of Central and South-West Asia: How Contagious is it?

    OpenAIRE

    Egert, Balazs

    2013-01-01

    This study seeks to determine the extent to which the former communist states of Central and South-West Asia are “infected” by the Dutch Disease. We take a detailed look at the functioning of the transmission mechanism of the Dutch Disease, i.e. the chains that run from commodity prices to real output in manufacturing. We complement this with two econometric exercises. First, we estimate nominal and real exchange rate models to see whether commodity prices are correlated with the exchange rat...

  12. Epidemiology of malaria in the Taabo health and demographic surveillance system, south-central Côte d’Ivoire

    OpenAIRE

    Bassa, Fidèle K.; Ouattara, Mamadou; Silué, Kigbafori D; Adiossan, Lukas G.; Baikoro, Nahoua; Koné, Siaka; N’Cho, Moussan; Traoré, Mahamadou; Bonfoh, Bassirou; Utzinger, Jürg; N’Goran, Eliézer K.

    2016-01-01

    Background A deep understanding of the local epidemiology of malaria is essential for the design and implementation of setting-specific control and elimination efforts. In Côte d’Ivoire, new initiatives are underway to reduce the burden of malaria, which requires high-quality longitudinal data. The epidemiology of malaria was studied in the Taabo health and demographic surveillance system (HDSS) in south-central Côte d’Ivoire and implications for control are discussed. Methods Two cross-secti...

  13. Isotopic composition of water from a mine drainage site in Creede County in south central Colorado

    Science.gov (United States)

    Michel, R. L.; Williams, M. W.; Krupicka, A.; Wireman, M.; Graves, J.

    2011-12-01

    Creede County in South Central Colorado was an active area of silver mining beginning in the early 1890s. To relieve flooding in some of the mines, the Nelson Tunnel was built in the late 1890s. This tunnel still exists and acid mine drainage from the tunnel eventually flows into the Willow Creek Watershed which eventually flows into the Upper Rio Grande. The water coming out of the tunnel is high in toxic metals and the area has become part of an EPA Superfund site in an effort to find a suitable method to remediate the metal problems. Among the approaches used in the program is the use of isotopes of water and carbon to identify sources and estimate ages of the water in the drainage. Samples were collected for analysis of isotopic ratios and tritium concentrations at a series of sites within the tunnel complex from 2008-2010. In 2009 samples were also collected for analysis of isotopes in groundwater and surface water. In 2010 sampling was expanded to include four precipitation and one snow sample. Tritium concentrations in precipitation and snowfall in 2010 ranged from 3-6 tritium units with the lowest concentration found in the snow sample. The 18O isotopic ratios in precipitation for this site ranged from an average of -8.9 o/oo in summer to about -19 o/oo in winter. The six groundwater samples collected in 2009 had an average 18O isotopic concentration of -15 o/oo and tritium concentrations ranging from 7.4-9.3 TU. These results suggest that the groundwater sampled is composed largely of a mixture of summer and winter precipitation with the latter source being dominant. The tritium concentrations in groundwater exceed recent precipitation concentrations, suggesting the presence of water from the bomb-tritium transient and an age of a decade or more for the groundwater. Eight sites in the tunnel were sampled I from 2008-2010, although not all sites were sampled every year. The sampling sites included waters seeping into the tunnel as well as the outlet water

  14. Energy Use and Energy Efficiency in Selected Arable Farms in Central and South Eastern Europe

    Directory of Open Access Journals (Sweden)

    Gerhard Moitzi

    2014-05-01

    Full Text Available Normal 0 21 false false false DE-AT X-NONE X-NONE Normal 0 21 false false false HR X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;} The main objective of the project “Mechanization and Energy use in selected arable farms in Central and South Eastern Europe (CASEE” was to analyse energy characteristics of arable farming in Slovak Republic, Romania, Serbia and Austria, to compare results and identify possibilities of its improvements. The large scale farms are: the university farm of the Slovak University of Agriculture (SK with 1.112 ha arable land, a cooperative farm in Risnovice (SK with an arable land of 1.266 ha, a family farm in Apahida-Transylvania (RO with 400 ha, a farm in Viisoara-Transylvania (RO with 600 ha, a family farm in Sremska Mitrovica (SRB with an arable land of 115 ha, a family farm near Novi Sad (SRB with an arable land of 450 ha and a family farm in Ansfelden/Linz (A with 368 ha. The farms were visited by the interviewer once or more times and the relevant data, used machinery, quantity of inputs, e.g. fuel, pesticides, fertilizer, seed and yields of harvested crops, were recorded, for the production season 2012. After collection of the basic data all energy inputs and outputs, energy content of crops, were calculated in accordance with data and procedure defined by CIGR (International Commission of Agricultural and Biosystems Engineering, Handbook Volume V

  15. An ethical analysis of the implementation of poverty reduction policies in South Africa and Chile and their implications for the Church

    OpenAIRE

    Louise Kretzschmar

    2014-01-01

    The focus of this contribution is the issue of poverty reduction within the South African and Chilean contexts. It is rooted in the academic field of Christian Ethics and also draws on several texts from the human and economic sciences. Policies adopted and practical steps taken to overcome poverty by the respective governments between 1990 and 2012 are evaluated and the theological and practical implications of poverty for the church are briefly highlighted. Despite differences between these...

  16. Blueberry production in Chile: current status and future developments

    Directory of Open Access Journals (Sweden)

    Jorge B. Retamales

    2014-03-01

    Full Text Available Chile has become a major actor in the blueberry industry as the most important supplier of off-season fresh fruit for the northern hemisphere. Blueberry exports passed from US$ 30 million (around 4,000 tons in 2000 to US$ 380 million (94,000 tons in 2011. The characteristics of the major blueberry growing regions (North, Central, South-central and South are presented in terms of acreage, varieties, management practices, extension of the harvest season, and soil and climatic conditions. Most fruit is from highbush varieties, picked by hand and exported fresh by boat to United States. Largest proportion of fruit is exported from mid December to late January, which coincides with lowest prices. The south-central region (latitudes 34º50' to 38º15' S was in 2007 the most important one with 5,075 ha (51.1% of area planted. Among the challenges for the Chilean blueberry industry in the near future are: 1. Lower profitability due to lower rates of currency exchange and higher costs, 2 - Greater scarcity and higher cost of labor, 3.- Need for higher productivity and sustainable production practices, 4- Fruit of high and consistent quality, and 5.- Greater investment in research. As a case study the article presents three approaches that can help identify areas with low availability of labor and improve its efficiency. The article shows the use of geomatic tools to establish labor availability, application of growth regulators to reduce crop load, increase fruit size and improve harvest efficiency, and the use of shakers to harvest fresh fruit for long distance markets. More research is needed to improve yields, reduce costs and give greater economical and ecological sustainability to the Chilean blueberry industry.

  17. Radioactive wastes management development in Chile

    International Nuclear Information System (INIS)

    A Facility for immobilizing and conditioning of radioactive wastes generated in Chile, has recently started in operation. It is a Radioactive Wastes Treatment Plant, RWTP, whose owner is Comision Chilena de Energia Nuclear, CCHEN. A Storgement Building of Conditioned Wastes accomplishes the facility for medium and low level activity wastes. The Project has been carried with participation of chilean professionals at CCHEN and Technical Assistance of International Atomic Energy Agency, IAEA. Processes developed are volume reduction by compaction; immobilization by cementation and conditioning. Equipment has been selected to process radioactive wastes into a 200 liters drum, in which wastes are definitively conditioned, avoiding exposition and contamination risks. The Plant has capacity to treat low and medium activity radioactive wastes produced in Chile due to Reactor Experimental No. 1 operation, and annex Laboratories in Nuclear Research Centers, as also those produced by users of nuclear techniques in Industries, Hospitals, Research Centers and Universities, in the whole country. With the infrastructure developed in Chile, a centralization of Radioactive Wastes Management activities is achieved. A data base system helps to control and register radioactive wastes arising in Chile. Generation of radioactive wastes in Chile, has found solution for the present production and that of near future

  18. Late Mesozoic to Paleogene stratigraphy of the Salar de Atacama Basin, Antofagasta, Northern Chile: Implications for the tectonic evolution of the Central Andes

    Science.gov (United States)

    Mpodozis, Constantino; Arriagada, César; Basso, Matilde; Roperch, Pierrick; Cobbold, Peter; Reich, Martin

    2005-04-01

    The Salar de Atacama basin, the largest "pre-Andean" basin in Northern Chile, was formed in the early Late Cretaceous as a consequence of the tectonic closure and inversion of the Jurassic-Early Cretaceous Tarapacá back arc basin. Inversion led to uplift of the Cordillera de Domeyko (CD), a thick-skinned basement range bounded by a system of reverse faults and blind thrusts with alternating vergence along strike. The almost 6000-m-thick, upper Cretaceous to lower Paleocene sequences (Purilactis Group) infilling the Salar de Atacama basin reflects rapid local subsidence to the east of the CD. Its oldest outcropping unit (Tonel Formation) comprises more than 1000 m of continental red sandstones and evaporites, which began to accumulate as syntectonic growth strata during the initial stages of CD uplift. Tonel strata are capped by almost 3000 m of sandstones and conglomerates of western provenance, representing the sedimentary response to renewed pulses of tectonic shortening, which were deposited in alluvial fan, fluvial and eolian settings together with minor lacustrine mudstone (Purilactis Formation). These are covered by 500 m of coarse, proximal alluvial fan conglomerates (Barros Arana Formation). The top of the Purilactis Group consists of Maastrichtian-Danian alkaline lava and minor welded tuffs and red beds (Cerro Totola Formation: 70-64 Ma K/Ar) deposited during an interval of tectonic quiescence when the El Molino-Yacoraite Late Cretaceous sea covered large tracts of the nearby Altiplano-Puna domain. Limestones interbedded with the Totola volcanics indicate that this marine incursion advanced westwards to reach the eastern CD slope. CD shortening in the Late Cretaceous was accompanied by volcanism and continental sedimentation in fault bounded basins associated to strike slip along the north Chilean magmatic arc to the west of the CD domain, indicating that oblique plate convergence prevailed during the Late Cretaceous. Oblique convergence seems to have

  19. Las áreas de filtración de metano constituyen zonas de agregación del bacalao de profundidad (Dissostichus eleginoides frente a Chile central?

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    Javier Sellanes

    2012-11-01

    Full Text Available Se presenta los resultados de dos campanas (invierno y verano de pesca de bacalao de profundidad (Dissostichus eleginoides, realizadas sobre un área de filtración de metano (AFM y un sitio aledano utilizado como control. Estas fueron desarrolladas con el objetivo de determinar si las AFM constituyen sitios de agregación de D. eleginoides. Para cada área se registró la captura promedio, el rendimiento de pesca y se determinó índices de abundancia y diversidad incluyendo la fauna capturada incidentalmente. Los ejemplares de bacalao de profundidad capturados en ambos sitios fueron sexados, medidos y pesados. Adicionalmente, se presentan imágenes tomadas in situ, dentro del AFM, que documentan la presencia tanto de D. eleginoides como aparejos de pesca perdidos utilizados en su captura frente a la costa de Concepción. Las mayores capturas y rendimientos fueron observadas en el AFM, con valores promedio de 56,2 kg por lance de pesca y rendimientos promedios de 80,3 g/anzuelo, siendo significativamente mayores en comparación al sitio control. La campana de pesca realizada en invierno registra mayores capturas y rendimientos en ambas áreas. La composición faunística evaluada a través de los índices comunitarios, indica diferencias significativas entre sitios, registrándose un mayor número de especies de fauna acompanante en el AFM, en comparación con el sitio control (18 y 14 especies, respectivamente. Se hipotetiza que la mayor abundancia de bacalao de profundidad en el AFM, estaría relacionada tanto con la mayor heterogeneidad espacial, dada por la presencia de arrecifes de carbonatos autigénicos, como con la disponibilidad de presas, constituyendo estos sitios como zonas de alimentación. El presente trabajo entrega información tendiente a establecer el rol ecológico de las AFM y la fauna asociada a ellas en ambientes batiales frente a Chile.

  20. Trail impacts and trail impact management related to ecotourism visitation at Torres del Paine National Park, Chile

    Science.gov (United States)

    Farrell, T.A.; Marion, J.L.

    2002-01-01

    Ecotourism and protected area visitation in Central and South America are largely dependent upon a relatively undisturbed quality of natural resources. However, visitation may impact vegetation, soil, water and wildlife resources, and degrade visitor facilities such as recreation sites and trails. Findings are reported from trail impact research conducted at Torres del Paine National Park in Patagonia, Chile. The frequency and magnitude of selected trail impacts and the relative effect of the amount of use, vegetation type, trail position and trail grade are investigated. Findings differed from previous studies in that amount of use was significantly related to both trail width increases and trail erosion. Management actions to minimize trail impacts are offered.

  1. Geometry of the inverted Cretaceous Chañarcillo Basin based on 2-D gravity and field data. An approach to the structure of the western Central Andes of northern Chile

    Directory of Open Access Journals (Sweden)

    F. Martínez

    2015-08-01

    Full Text Available This paper discusses an integrated approach that provides new ideas about the structural geometry of the NNE-striking, Cretaceous Chañarcillo Basin located along the eastern Coastal Cordillera in the western Central Andes of northern Chile (27–28° S. The results obtained from the integration of two transverse (E–W gravity profiles with previous geological information, show that the architecture of this basin is defined by a large NNE–SSE-trending and east-vergent anticline ("Tierra Amarilla Anticlinorium", which is related to the positive reactivation of a former Cretaceous normal fault (Elisa de Bordos Master Fault. Moreover, intercalations of high and low gravity anomalies and steep gravity gradients reveal a set of buried, west-t