Lazcano, J.; Godoy, B.; Aguilera, F.; Wilke, H.
to 7 km and come from the Young Cone summit, covering the lava flows erupted in the previous stage. Thus, according with the presented evolution, Paniri is similar to San Pedro, Cerro del León, and Toconce volcanoes, distributed in SPLVC. Stratigraphic relation, glacial erosion and radiometric dating indicate that this volcano is younger than Cerro del Leon and Toconce southwards, both showing a marked hydrothermal alteration (López et al., 2012; Silva et al., 2012), and older than Chao Dacite, and San Pedro - San Pablo volcanic complex. No historical activity have been observed for Paniri volcano. References López, C., Aguilera, F., Godoy, B., Wörner, G., y Kojima, S., 2012. Evolución del sitema volcánico Toconce (Región de Antofagasta, Chile) mediante interpretación fotogeológica, petrográfica y geoquímica. In XIII Congreso Geológico Chileno. 13 - 17 agosto, Antofagasta, Chile. Silva, F., Aguilera, F., Godoy, B., Wörner, G., y Kojima, S., 2012. Evolución del sitema volcánico Cerro del León (Región de Antofagasta, Chile) mediante interpretación fotogeológica, petrográfica y geoquímica. In XIII Congreso Geológico Chileno. 13 - 17 agosto, Antofagasta, Chile.
Thierer, P. O.; Tilmann, F.; Flueh, E. R.; Kopp, H.; Comte, D.
The SPOC experiment was carried out as a combined on- /offshore experiment using FS SONNE (cruise SO 161) to investigate the effects of subducting seamounts and fracture zones on the seismicity and structure of the Central Chilean margin off Valparaiso, Chile. The working area is characterised by the ongoing subduction of the oceanic Nazca Plate under the South American continent and shows highly segmentation. North of Valparaiso the subduction angle is very low (flat slab) and we observe only minor sediment input into the trench. In contrast we observe a steep dip angle and high sedimentation rates in the south. Segment boundaries commonly coincide with e.g. bathymetric highs as in this case the Juan Fernandez Ridge which interrupts the lateral, south-north going material flow along the trench. Local earthquake monitoring was carried out for a period of ten weeks using two marine subarrays totally comprising 23 ocean bottom instruments (OBH and OBS). Seismological land data from the Central Chilean Network (CCN) and a number of temporary land stations supplement the marine data set. We present results of about 600 hypocenter determinations detected on the marine OBH/S recordings and the temporary land stations. The hypocenter distribution shows a considerable seismic activity below the upper part of the continental margin. Due to the geometry of the arrays which focus on the transitional domain of the slope we can map the seaward termination of the seismogenic zone using a compilation of both data sets. The southern marine subarray registered a swarm of shallow earthquakes, located on top of the already subducted Topocalma Knoll. A relation to this seamount subduction is strongly indicated. Next to the Juan Fernandez Seamount on the outer rise, we observe considerable seismic activity.
Mesias, Jorge M.
The summer upwelling circulation off Central Chile between 34°--40°S is studied using the Princeton Ocean Circulation numerical model, implemented with realistic atmospheric forcings and bottom topography. The simulations are made for summers of years 1992, 1993, and 1994. Sea surface temperature (SST) from the model results and satellite sensors (derived from NASA/NOAA Pathfinder Project datasets) are compared to determine regions where the numerical simulations more realistically represent the oceanic fields. The summer local winds are predominantly equatorward and fluctuate affected by the seasonal displacement of the Subtropical Anticyclone of the Southeast Pacific. The model ocean circulation shows the presence of a surface coastal equatorward jet flowing over a poleward undercurrent that spreads over the continental shelf and slope break. These currents resemble those historically observed off Central Chile, following a classical Ekman-geostrophy dynamics. The oceanic variability is strongly related to the variability of the local wind forcing, bottom relief, and coastline geometry. Strong wind fluctuations induce the formation of cyclonic/anticyclonic mesoscale eddies, favored by the separation of the equatorward jet from the coast, downstream of a prominent mid-domain cape. The flow variability between regions depends on the spatial variability of the wind forcing. The wind relaxation is larger in the southern regions, where the upwelling tends to disappear. In the northern areas, the separation of the jet and the formation of eddies induce a strong cross-shelf transport activity. Comparisons among SST fields for all years indicate that the model and satellite fields vary in similar patterns, especially in the northern coastal areas, and suggest that oceanic fields are largely affected by changes in local winds during El Nino events. During El Nino periods, the upwelling activity weakens due to a rapid decrease of the equatorward winds, and the passage of
Krawczyk, C. M.; Stiller, M.; Mechie, J.; Lueth, S.; Wigger, P.; Oncken, O.; Reichert, C.; Bataille, K.
Nearly all interplate megathrust earthquakes occur in the seismogenic coupling zone between converging plates. In the area of the 1960 Chile earthquake (Mw = 9.5), we aim at a quantitative understanding of the seismicity and its relation to processes operating at depth and at the surface. As a first step, the offshore experiment SPOC with RV SONNE was combined with an onshore-offshore, active-passive seismic experiment between 36\\deg and 39\\deg S, crossing the rupture area of the 1960 Chile earthquake. The campaign comprised: (1) a 2-D wide-angle component recording chemical shots and airgun pulses along three consecutive E-W onshore profiles; (2) a seismic reflection experiment in the onshore-offshore transition; and (3) a 3-D component which recorded both active and passive sources. Offshore, the upper plate is split into many segments with pronounced forearc basins and a narrow accretionary wedge. A thick subduction channel seems to cause a non-frontally accreting subduction mode. Along the westernmost part of the southernmost E-W refraction seismic line, the profile spread of the active reflection seismic survey at 38\\deg 15' S was 54 km long, and also recorded the airgun shots of the marine profile with the first 18 km of its spread. Different mainly eastward dipping reflection bands are observed. Between 5-25 km depth the internal structure of the Palaeozoic accretionary wedge is described. Reflections between 16-42 km correlate with Wadati-Benioff seismicity and are interpreted as imaging the top of the downgoing plate. In the central part of the profile a break in reflectivity located below the axis of the coastal cordillera more or less coincides with the intersection between the oceanic plate and the continental Moho. This break in reflectivity also approximately correlates with the downdip end of the seismogenic plate interface as defined by geodetic modelling. These new seismic data provide the geometry of the subduction zone in the area, and hence
Garrett, Ed; Shennan, Ian; Gulliver, Pauline; Woodroffe, Sarah
A lack of comprehensive understanding of the seismic hazards associated with a subduction zone can lead to inadequate anticipation of earthquake and tsunami magnitudes. Four hundred and fifty years of Chilean historical documents record the effects of numerous great earthquakes; however, with recurrence intervals between the largest megathrust earthquakes approaching 300 years, seismic hazard assessment requires longer chronologies. This research seeks to verify and extend historical records in south central Chile using a relative-sea level approach to palaeoseismology. Our quantitative, diatom-based approaches to relative sea-level reconstruction are successful in reconstructing the magnitude of coseismic deformation during recent, well documented Chilean earthquakes. The few disparities between my estimates and independent data highlight the possibility of shaking-induced sediment consolidation in tidal marshes. Following this encouraging confirmation of the approach, we quantify land-level changes in longer sedimentary records from the centre of the rupture zone of the 1960 Valdivia earthquake. Here, laterally extensive marsh soils abruptly overlain by low intertidal sediments attest to the occurrence of four megathrust earthquakes. Sites preserve evidence of the 1960 and 1575 earthquakes and we constrain the timing of two predecessors to 1270 to 1410 and 1050 to 1200. The sediments and biostratigraphy lack evidence for the historically documented 1737 and 1837 earthquakes.
Rodríguez, I.; Roche, O.; Moune, S.; Aguilera, F.; Campos, E.; Pizarro, M.
The Irruputuncu is an active volcano located in northern Chile within the Central Andean Volcanic Zone (CAVZ) and that has produced andesitic to trachy-andesitic magmas over the last ˜258 ± 49 ka. We report petrographical and geochemical data, new geochronological ages and for the first time a detailed geological map representing the eruptive products generated by the Irruputuncu volcano. The detailed study on the volcanic products allows us to establish a temporal evolution of the edifice. We propose that the Irruputuncu volcanic history can be divided in two stages, both dominated by effusive activity: Irruputuncu I and II. The oldest identified products that mark the beginning of Irruputuncu I are small-volume pyroclastic flow deposits generated during an explosive phase that may have been triggered by magma injection as suggested by mingling features in the clasts. This event was followed by generation of large lava flows and the edifice grew until destabilization of its SW flank through the generation of a debris avalanche, which ended Irruputuncu I. New effusive activity generated lavas flows to the NW at the beginning of Irruputuncu II. In the meantime, lava domes that grew in the summit were destabilized, as shown by two well-preserved block-and-ash flow deposits. The first phase of dome collapse, in particular, generated highly mobile pyroclastic flows that propagated up to ˜8 km from their source on gentle slopes as low as 11° in distal areas. The actual activity is characterized by deposition of sulfur and permanent gas emissions, producing a gas plume that reaches 200 m above the crater. The maximum volume of this volcanic system is of ˜4 km3, being one of the smallest active volcano of Central Andes.
Central Chile has a 470-year-long written earthquake history, the longest of any part of the country. Thanks to the early and continuous Spanish settlement of this part of Chile (32°- 35° S), records document destructive earthquakes and tsunamis in 1575, 1647, 1730, 1822, 1906 and 1985. This sequence has promoted the idea that central Chile's large subduction inter-plate earthquakes recur at regular intervals of about 80 years. The last of these earthquakes, in 1985, was even forecast as filling a seismic gap on the thrust boundary between the subducting Nazca Plate and the overriding South America Plate. Following this logic, the next large earthquake in metropolitan Chile will not occur until late in the 21st century. However, here I challenge this conclusion by reporting recently discovered historical evidence in Spain, Japan, Peru, and Chile. This new evidence augments the historical catalog in central Chile, strongly suggests that one of these earthquakes previously assumed to occur on the inter-plate interface in fact occurred elsewhere, and forces the conclusion that another of these earthquakes (and its accompanying tsunami) dwarfed the others. These findings complicate the task of assessing the hazard of future earthquakes in Chile's most populated region.
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
Heyde, I.; Kopp, H.; Reichert, C.
Gravity measurements were carried out during RV SONNE cruise SO-161 (SPOC) in late 2001 between 28° S and 44° S offshore Central Chile along a total length of about 17500 km. The mean accuracy of the data measured with the seagravimeter system KSS31M of BGR is better than 1 mGal. Further foreign marine gravity data were not included due to their considerable lower accuracy. Additional marine gravity data derived from satellite altimetry are needed to augment our data from the survey area. The SPOC data set was compared with 3 different satellite gravity data compilations. The data set with the best statistical results for the gravity differences was used for further gravity map compilations. The map of the freeair gravity is dominated by the anomalies of the main topographic features in the survey area. In the W the oceanic crust of the subducting Nazca Plate is characterized by weak positve gravity anomalies. Landward the anomalies decrease rapidly to less than minus 150 mGal in the Chilean trench. Further towards the coast extends a broad zone of alternating positve and negative freeair gravity anomalies. These could be interpreted either in terms of morphology of the continental slope or heterogeneous density distribution in the upper crust. Additionally Bouguer gravity anomalies were calculated. The anomalies on the Nazca Plate are strongly positive with a clear south - north trending increase of values, which reflect the increasing age of the oceanic crust. The effect of isostatic compensation was calculated assuming Vening-Meinesz models with different parameters. The gravity effect of the isostatic compensation root was eliminated from the Bouguer gravity anomalies and serves as a residual field. The interpretation of isostatic residual fields in this complicated tectonic environment leads to the detection of a series of offshore basins. In the N and the centre of the survey area the distribution of the profiles is rather uniform. For these areas 3D
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.
Charrier, Andrés; Correa, Claudio; Castro, Camila; Méndez, Marco A
Based on morphological and molecular evidence (mitochondrial and nuclear sequences) we describe a new species of spiny-chest frog, Alsodes cantillanensis, from central Chile (around 34°S). The type locality, Quebrada Infiernillo, is located in the Coastal Range at approximately 65 km from Santiago (Metropolitan Region), the capital of Chile. The distribution of the new species is included entirely in that of A. nodosus (32-36°S approximately), which was identified as the sister taxon according to molecular phylogenetic analyses. Moreover, both species are sympatric in the type locality. The new species was found in a Nothofagus macrocarpa relict forest potentially threatened by gold mining activities. We identify other threats for its conservation and some biological data needed for understanding the evolution of this species. This discovery reveals the scarce knowledge about biogeography, evolution and ecology of spiny-chest frogs from central Chile.
Chávez Hoffmeister, Martín; Carrillo Briceño, Jorge D.; Nielsen, Sven N.
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
Aedo, J R; Belk, M C; Habit, E M
Percilia irwini from the Andalién and Biobío River basins of south-central Chile exhibited a mean age of 1.4 years with a maximum age of 4 years. Size at age differed among river zones and males were 10% larger than females at all ages. Compared to other locations, populations of P. irwini inhabiting areas subject to industrial and domestic effluents exhibited smaller size structure.
Hormazabal, Samuel; Morales, Carmen; Cornejo, Marcela; Bento, Joaquim; Valencia, Luis; Auger, Pierre; Rodriguez, Angel; Correa, Marco; Anabalón, Valeria; Silva, Nelson
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
Vergara, Odette A.; Echevín, Vincent; Sepúlveda, Héctor H.; Colas, Francois; Quiñones, Renato A.
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.
Krawczyk, C. M.; Stiller, M.; Lüth, S.; Mechie, J.; Spoc Research Group
Nearly all interplate megathrust earthquakes occur in the seismogenic coupling zone between converging plates. In the area of the 1960 Chile earthquake (Mw = 9.5), we aim at a quantitative understanding of the seismicity and its relation to processes operating at depth and at the surface. As a first step, the offshore experiment SPOC with RV SONNE was combined with an onshore-offshore, active-passive seismic experiment between 36° and 39° S, crossing the rupture area of the 1960 Chile earthquake. The campaign comprised: (1) a 2-D wide-angle component recording chemical shots and airgun pulses along three consecutive E-W onshore profiles; (2) a seismic reflection experiment in the onshore-offshore transition; and (3) a 3-D component which recorded both active and passive sources. Offshore, the upper plate is split into many segments with pronounced forearc basins and narrow accretionary wedges. A thick subduction channel seems to cause a non-accretionary subduction mode. Covering onshore the westernmost part of a long E-W refraction seismic line (one amongst three), the profile spread of the reflection seismic survey at 38° 15`S was 54 km long, with three set-ups of 18 km length each, and extended from the coast to the east. Furthermore, the offshore-onshore transition zone is imaged by a wide-angle section resulting from the registration of the airgun shots of the marine profile with the first 18 km of the spread of the NVR survey. Different mainly eastward dipping reflection bands are observed between 5-25 km depth. These bands are interpreted to describe the internal structure of the Palaeozoic accretionary wedge in the region. The reflections between 25-45 km depth correlate with Wadati-Benioff seismicity and are suggested to image the top of the downgoing plate. Below the coast, the plate dips with c. 15° below the continent. In the central part of the profile, a break in reflectivity located below the axis of the coastal cordillera more or less coincides
Manea, M.; Perez-Gussinye, M.; Manea, V.; Fernandez, M.
Subduction of oceanic plates beneath large continental masses is a rare process and at present it occurs only along western South America and Central Mexico. Likewise, flat subduction, understood here as where the slab enters at a normal angle and reverses its curvature to flatten at ~70-120 km depth, only occurs at present beneath South America. In general, the angle at which subduction occurs in the depth range of ~100 to ~200 km reflects the balance between negative buoyancy of the slab, elastic resistance of the slab to change the angle of subduction, and non-hydrostatic pressure forces induced by subduction-driven flow within the asthenosphere. The latter force, known as suction force, acts to prevent the slab from sinking into the mantle, and its magnitude increases with increasing subduction velocity, narrowness and viscosity decrease of the mantle wedge [Manea and Gurnis, 2007]. Recent observations show that the upper plate structure varies along the Andean margin, indicating that it is thicker and stronger above flat subduction zones and suggesting a correlation between upper plate structure and subduction angle [Pérez-Gussinyé et al., 2008; Booker et al., 2004]. In this study we use numerical models to explore the extent to which upper plate structure, through its influence on asthenospheric wedge shape and viscosity, can affect the angle of subduction. We test for which upper plate thickness and asthenospheric viscosity repeated cycles of steep and flat subduction are reproduced and compare our results to estimations of lithospheric thickness and the duration of flat and steep subduction cycles hypothesized along the Andean margin. Our models are constrained by realistic plate velocities in hot spot reference frame for both Nazca and South American plates [Muller et al., 2008], the Miocene-Present shortening for the Andes [Schelart et al., 2007] and realistic Nazca plate age distribution [Sdrolias and Muller, 2006]. Using the finite element package
Campos, J.; Hatzfeld, D.; Madariaga, R.; Lopez, G.; Kausel, E.; Zollo, A.; Iannacone, G.; Fromm, R.; Barrientos, S.; Lyon-Caen, H.
We study the possible seismic gap in the Concepción-Constitución region of south-central Chile and the nature of the M=7.8 earthquake of January 1939. From 1 March to 31 May 1996 a seismic network of 26 short period digital instruments was deployed in this area. We located 379 hypocenters with rms travel time residuals of less than 0.50 s using an approximate velocity distribution. Using the VELEST program, we improved the velocity model and located 240 high precision hypocenters with residuals less than 0.2 s. The large majority of earthquakes occurred along the Wadati-Benioff zone along the upper part of the downgoing slab under central Chile. A few shallow events were recorded near the chain of active volcanos on the Andes; these events are similar to those of Las Melozas near Santiago. A few events took place at the boundary between the coastal ranges and the central valley. Well constrained fault plane solutions could be computed for 32 of the 240 well located events. Most of the earthquakes located on the Wadati-Benioff zone had "slab-pull" fault mechanism due to tensional stresses sub-parallel to the downgoing slab. This "slab-pull" mechanism is the same as that of eight earthquakes of magnitude around 6 that are listed in the CMT catalog of Harvard University for the period 1980-1998. This is also the mechanism inferred for the large 1939 Chilean earthquake. A very small number of events in the Benioff zone had "slab-push" mechanisms, that is events whose pressure axis is aligned with the slab. These events are found in double layered Wadati-Benioff zones, such as in northern Chile or Japan. Our spatial resolution is not good enough to detect the presence of a double layer, but we suspect there may be one.
MacDonell, Shelley; Vivero, Sebastian; McPhee, James; Ayala, Alvaro; Pellicciotti, Francesca; Campos, Cristian; Caro, Dennys; Ponce, Rodrigo
Water is a critical resource in the northern and central regions of Chile, as the area supports more than 40% of the country's population, and the regional economy depends on agricultural production and mining, which are two industries that rely heavily on a consistent water supply. Due to relatively low rates of rainfall, meltwater from snow and ice bodies in the highland areas provides a key component of the annual water supply in these areas. Consequently, accurate estimates of the rates of ablation of the cryosphere (i.e. snow and ice) are crucial for predicting current supply rates, and future projections. Whilst snow is generally a larger contributor of freshwater, during periods of drought, glaciers provide a significant source. This study aims to determine the contribution of glaciers to two catchments in northern and central Chile during a 2.5 year period, which largely consisted of extreme dry periods, but also included the recent El Niño event. This study combined field and modelling studies to understand glacier and rock glacier contributions in the Tapado (30°S), Yeso (33°S) catchments. In the field we undertook glaciological mass balance monitoring of three glaciers, monitored albedo and snow line changes using automatic cameras for three glaciers, measured discharge continuously at several points, installed six automatic weather stations and used thermistors to monitor thermal regime changes of two rock glaciers. The combination of these datasets where used to drive energy balance and hydrological models to estimate the contribution of ice bodies to streamflow in the two studied catchments. Over the course of the study all glaciers maintained a negative mass balance, however glaciers in central Chile lost more mass, which is due to the higher melt rates experienced due to lower elevations and higher temperatures. Areas free of debris generally contributed more to streamflow than sediment covered regions, and snow generally contributed more over
Yanez, E.; Barbieri, M.A.; Catasti, V.
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 in Central Chile. Relationships between species yields and thermics gradients (GRT) were found significant. Jack mackerel (Trachuru 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 of the kind of boats considered in this paper.
In contrast to the legendary upwelling that is present along the Peruvian and northern Chilean coasts, the coastal ocean off central Chile presents a highly seasonal upwelling regime that extends from early spring to mid fall. This region is also affected by a strong subsurface poleward flow, which transports southward low-oxygen water from the eastern equatorial Pacific. Coastal waters are highly productive due to upwelling, but the upwelled source waters are very low in oxygen and may produce hypoxia near the bottom over the continental shelf. The spatial structure and main scales of variability of the upwelling cells and dissolved oxygen are poorly understood off central Chile. One of the main limitations has been the lack of direct information. During the last years an observational program has been conducted over the relatively wide continental shelf off Concepción (36°30' S). This program has included ship-based (monthly) time-series, underwater glider observations and time-series based on moored sensors. Here, based on physical (temperature, salinity, pressure, velocity), biological (chlorophyll fluorescence) and chemical (dissolved oxygen) information, we analyze the main scales of time variability of the upwelling, the coastal currents and their impact on the dissolved oxygen. The cross-shelf structure of the upwelling region was sampled using underwater gliders capable of sampling the entire water column to a maximum of 1000 m and from near shore to 200 km offshore.
Bertin, Angéline; Inostroza, Pedro A; Quiñones, Renato A
While the presence of steroid estrogens in the environment has become a major environmental and health concern, their occurrence in coastal sediments remains poorly characterized. In this study, we measured the levels of three natural (estrone, 17β-estradiol, estriol) and one synthetic (17α-ethinylestradiol) estrogens in 54 coastal sediment samples collected from nine locations off central-southern Chile. Steroid estrogens were found in every sample. Remarkably high levels of 17α-ethinylestradiol were detected, reaching up to 48.14 ng/g dry weight. As a result, the global estrogenic loads were estimated to be high at all sites. Interestingly, they were found to correlate with the size of human populations served by sewage plants. Our study indicates that 17α-ethinylestradiol may accumulate in coastal sediments. The possible impact of this highly potent synthetic estrogen on the biota of the marine ecosystem off central-south Chile and on human health remains an open question.
Muñoz-Pedreros, Andrés; Yáñez, José; Norambuena, Heraldo V; Zúñiga, Alfredo
The South American Grey Fox (Lycalopex griseus) is a canid widely distributed in southern South America, however some aspects of its biology are still poorly known. We studied the diet and density of L. griseus in the Lago Peñuelas Biosphere Reserve, in Central Chile. The trophic niche breadth was B = 6.16 (Bsta = 0.47) and prey diversity was H ' = 2.46 (Hmax' = 3.17, J' = 0.78). The highest proportions of prey consumed in the diet were Oryctolagus cuniculus (52.21%) and other mammals (32.78%). We compared these results with a latitudinal gradient of diet results for this species in Chile. L. griseus eats mostly mammals (> 90% of total prey), consuming the rodent Phyllotis darwini and reptiles in the Northern zone; O. cuniculus, Octodon degus and Abrocoma bennetti in the Central zone; Abrothrix spp. and lagomorphs in the Southern zone; and Lepus capensis and Ovis aries in the Austral zone. The estimated density of L. griseus in Lago Peñuelas NR was 1.3 foxes /km(2) . This article is protected by copyright. All rights reserved.
Thierer, P. O.; Flueh, E. R.; Kopp, H.; Tilmann, F.; Gaedicke, C.; Schreckenberger, B.
The main goal of the RV SONNE cruise 161 SPOC (Subduction Processes Off Chile), Leg 1 and 4, was to investigate the effects of subducting aseismic ridges and frac- ture zones on the seismicity and structure of the Central Chilean Margin. Scientists from GEOMAR (Kiel), BGR (Hannover), FU Berlin (SFB 267), Universidad de Chile (Santiago) and Instituto Costaricense de Electricidad (Costa Rica) participated in data acquisition and analysis. The SPOC experiment consists of four consecutive legs off Valparaiso, Central Chile. During Leg 1 (October), an array of 23 ocean bottom hydrophons and seismome- ters (OBH/S) was deployed to register local earthquakes. In December (Leg 4), the network was recovered and a total of 125 OBH/S locations were occupied on five wide-angle profiles. They recorded more than 10.000 airgun shots, fired by an airgun array of 20 guns with a total volume of 50 liters. In addition, the wide-angle seis- mic lines were extended by land-based seismometers, operated by the Universidad de Chile, Santiago. Furthermore gravity, magnetics and high resolution bathymetry (SIMRADTM) and sediment echo-sound data (PARASOUNDTM) were recorded. On Legs 2 and 3, the BGR carried out a multi-channel reflection (MCS) seismic survey. Preliminary analysis of the data shows that a considerable number of local earthquakes has been recorded by the passive seismological network. Preliminary location of the hypocenters yield earthquake depths predominantly between 15 and 30 km. Many events registered by the local seismological network have been relocated~10 km west- wards of the previous land-based locations, which might indicate a bias in the existing catalogues. Wide-angle record sections of high quality were obtained, for all profiles shot. Mantle phases over offsets of more than 120 km were recorded by many stations. The pre- liminary velocity depth model derived for a profile striking E-W at 31a S across the subduction zone resolved the lateral transition on the
Spiske, M.; Bahlburg, H.
On 27th February, 2010, at 03:34 a.m. local time, a MW 8.8. earthquake occurred off the coast of central Chile. The triggered tsunami affected the coast from Valparaiso in the north to Tirua, about 650 km further south. During our field survey which was conducted four weeks after the event, we studied erosional and depositional impact of the tsunami. The tsunami deposited fine grained sediments, such as sand layers or fine grained caps, often covering plants or pre-tsunami soil. Boulders were only available at two locations: Bucalemu and Isla Mocha. While Isla Mocha offered a natural setting, boulders in Bucalemu where artificially dumped close to the shore in order to construct a break water a few days before the tsunami hit. This coincidence made Bucalemu a perfect setting for studying boulder transport by a tsunami because (1) the pre-transport setting is well defined, (2) exact transport distances can be measured, and (3) flow depth of ca. 2 m and flow speed of at least 5.6 m/s are known from eyewitnesses accounts and video recordings. Additionally, the coastal plain of Bucalemu is crossed by a river and backflow followed the river bed so that no erosion or modification of the run up sediments occurred. The size of the artificially quarried boulders was restricted to max. 0.3 m3 and 720 kg, with the boulders having uniform triangular shapes. Calculations show that the tsunami would have been capable to transport even bigger boulders. A fining landward trend of boulder size is not present because of the narrow spectrum of boulder sizes available at this location. Boulders were probably transported by rolling or even saltation because of their relatively small weight and a flow speed of at least 5.6 m/s. The boulders are deposited in three groups in different distances to the pile where they originate from. A boulder free zone separates group I and II. Transition zones with only a few randomly scattered boulders are found in landward direction of group II and III
Dure, Tina; Cisternas, Marco; Horton, Benjamin; Ely, Lisa; Nelson, Alan R.; Wesson, Robert L.; Pilarczyk, Jessica
The ∼500-year historical record of seismicity along the central Chile coast (30–34°S) is characterized by a series of ∼M 8.0–8.5 earthquakes followed by low tsunamis (<4 m) occurring on the megathrust about every 80 years. One exception is the AD 1730 great earthquake (M 9.0–9.5) and high tsunami (>10 m), but the frequency of such large events is unknown. We extend the seismic history of central Chile through a study of a lowland stratigraphic sequence along the metropolitan coast north of Valparaíso (33°S). At this site, higher relative sea level during the mid Holocene created a tidal marsh and the accommodation space necessary for sediment that preserves earthquake and tsunami evidence. Within this 2600-yr-long sequence, we traced six laterally continuous sand beds probably deposited by high tsunamis. Plant remains that underlie the sand beds were radiocarbon dated to 6200, 5600, 5000, 4400, 3800, and 3700 cal yr BP. Sediment properties and diatom assemblages of the sand beds—for example, anomalous marine planktonic diatoms and upward fining of silt-sized diatom valves—point to a marine sediment source and high-energy deposition. Grain-size analysis shows a strong similarity between inferred tsunami deposits and modern coastal sediment. Upward fining sequences characteristic of suspension deposition are present in five of the six sand beds. Despite the lack of significant lithologic changes between the sedimentary units under- and overlying tsunami deposits, we infer that the increase in freshwater siliceous microfossils in overlying units records coseismic uplift concurrent with the deposition of five of the sand beds. During our mid-Holocene window of evidence preservation, the mean recurrence interval of earthquakes and tsunamis is ∼500 years. Our findings imply that the frequency of historical earthquakes in central Chile is not representative of the greatest earthquakes and tsunamis that the central Chilean subduction zone has
Gelcich, Stefan; Godoy, Natalio; Prado, Luis; Castilla, Juan Carlos
To combine the rational use of marine benthic resources and economic development of small-scale fishers, Chile passed legislation in 1991 establishing a comanagement policy that grants exclusive territorial user rights for fisheries (TURFs) to artisanal fisher organizations in well-defined inshore coastal areas, known as Management and Exploitation Areas for Benthic Resources (MEABRs). In general the policy has been proclaimed a management and economic success because benthic resource abundances have increased inside MEABRs in comparison with open-access areas. However, there is a lack of studies assessing the impact of this management policy on nontargeted subtidal species and community assemblages and the policy's implications for biodiversity and conservation. This study starts to fill this gap and links the allocation of TURFs for benthic resources with add-on conservation benefits for species that are not directly linked with the fishery policy. Comparative subtidal surveys inside vs. outside MEABRs were used to assess the effects of three MEABRs on managed targeted benthic species, biodiversity (species richness), and community assemblages in central Chile. Surveys focused exclusively on subtidal kelp forest habitats dominated by Lessonia trabeculata, spanning 4-12 m in depth and with similar levels of habitat complexity. The study comprised: (1) quantification of kelp forest complexity, (2) understory survey of sessile species, (3) quantification of conspicuous benthic macroinvertebrates, including those under management, and (4) quantification of reef-fish species inside the kelp habitat. Results showed population enhancement of target-managed invertebrates inside MEABRs. Moreover, reef-fish species were significantly more diverse and abundant inside MEABRs, and community assemblages of nontarget benthic invertebrates and reef fish were significantly different inside vs. outside MEABRs. The comanagement of inshore benthic resources in Chile, through MEABRs
Bazán-León, E A; Lareschi, M; Sanchez, J; Soto-Nilo, G; Lazzoni, I; Venegas, C I; Poblete, Y; Vásquez, R A
Fleas associated with small mammals from seven localities from northern and central Chile were assessed. We captured 352 small mammals belonging to 12 species from which we obtained 675 fleas belonging to 15 different species. The most frequently captured flea species were Neotyphloceras crassispina crassispina (n = 198) and N. chilensis (n = 175). High values of flea species richness and diversity were found in Fray Jorge National Park (NP), a north-central Chilean site, whereas the highest values of mean abundance (MA) and prevalence were found in three diverse sites that include Los Molles River, a high altitude site located in north-central Chile, Fray Jorge NP and Dichato, in south-central Chile. On the other hand, high values of flea richness and diversity were found on two rodent species, Abrothrix olivacea and A. longipilis, whereas the highest values of MA and prevalence were found on Oligoryzomys longicaudatus, A. longipilis and Phyllotis xanthopygus. A total of three new host recordings, nine new localities and nine new host species and locality recordings are reported. Also, this study represents the first known record of Tetrapsyllus (Tetrapsyllus) comis in Chile and the first ecological analysis of Neotyphloceras chilensis.
Rubio, André V; Hidalgo-Hermoso, Ezequiel; Bonacic, Cristian
Hematology and serum biochemistry values were determined for 31 healthy captive and free-ranging Culpeo foxes (Lycalopex culpaeus) sampled in central Chile between 2008 and 2012. The influences of sex, age, and origin (captive versus free-ranging foxes) on the blood parameters were evaluated. The blood values determined were generally comparable to commonly reported values for other wild canid species and the domestic dog. No differences attributable to sex were observed for any parameter. Juveniles had higher levels of alkaline phosphatase and phosphorus and lower values of mean corpuscular hemoglobin concentration, blood urea nitrogen, total protein, and globulin than adult foxes. Captive and free-ranging animals differed in glucose and albumin values. This is the first study on blood parameters of the Culpeo fox and represents a contribution for clinical evaluations of this carnivore in captivity as well as in the wild.
Morales, Bárbara; Ruiz, Álvaro; Lacouture, Sonia; Gottschalk, Marcelo
The characteristics of 29 Chilean field strains of Streptococcus suis recovered between 2007 and 2011 from pigs with clinical signs at different farms were studied. Serotyping with use of the coagglutination test revealed that all but 1 strain belonged to serotype 6; the remaining strain was serotype 22. All the serotype-6 strains were suilysin (hemolysin)-negative; in addition, they were found to be genotypically homogeneous by enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction (ERIC-PCR) and sensitive to ampicillin, ceftiofur, penicillin, and trimethoprim/sulfamethoxazole. The results indicate that, in contrast to what is generally observed in other countries, a single clone of S. suis was isolated from diseased pigs in the central region of Chile. PMID:26424917
Piquer, Jose; Hollings, Pete; Rivera, Orlando; Cooke, David R.; Baker, Michael; Testa, Francisco
The Andes of central Chile are composed mostly of Cenozoic volcanic rocks, erupted during the opening and subsequent inversion of the intra-arc volcano-tectonic Abanico Basin. Until recently, the internal segmentation of this inverted basin was poorly understood. Based on a combination of U-Pb geochronology, (U-Th)/He thermochronology, whole rock geochemistry and structural data, we propose that the Abanico Basin can be divided into two main segments, separated by the NW-striking Piuquencillo fault and conjugate, NE-striking faults. Stratigraphic units defined in the northern segment (Abanico and Farellones formations) cannot be correlated with the rocks of the southern segment (Coya-Machali Formation and Teniente Volcanic Complex) in terms of lithofacies, depositional ages and geochemistry. The northern and southern segments also show temporal differences in their tectonic evolution. An early deformation event beginning at 22 Ma affected only the northern segment and is associated with the formation of progressive unconformities between the Abanico and Farellones formations, and also with crustal thickening as reflected in the geochemistry of the Farellones Formation. A second stage of crustal thickening and exhumation began at 12 Ma, as suggested by a sharp increase of the La/Yb ratios in the northern segment. In the southern segment, this event is reflected by only a moderate increase of La/Yb ratios, and by the transition between the Coya-Machali Formation and the Teniente Volcanic Complex. Finally, a third stage of exhumation and crustal thickening beginning at 7 Ma affected both the northern and southern segments. This last stage was the main exhumation event affecting the rocks of the Andes of central Chile, and is recorded in the geochemistry of igneous rocks by a sharp increase in the La/Yb ratios in the southern segment.
Hartley, Adrian J.; May, Geoffrey; Chong, Guillermo; Turner, Peter; Kape, Stephanie J.; Jolley, Elizabeth J.
In order to understand the response of a continental forearc to changes in subduction-zone geodynamics, we constructed a high-resolution chronostratigraphic cross section across the Central Andean forearc of northern Chile (21° 24°S). The tectono-stratigraphic development of the forearc differs from established models. No relationship was found between changes in rate of relative plate convergence and amount and style of deformation. Forearc response to continual compression since the Oligocene has been uplift and segmentation into discrete tectono-stratigraphic zones. From west to east, these zones are the extensional Coastal Cordillera, the extensional and/or transtensional Central depression, and the transpressional and/or compressional Precordillera-Preandean depression. Each area has recorded almost continuous sedimentation from Oligocene (?Eocene) time to the present day. Accommodation space has been generated by basin-margin uplift rather than active subsidence. We propose a model in which uplift of the leading edge of the South American plate is driven by subcrustal accretion of material removed at the trench by subduction erosion. Uplift and subduction erosion result in the trenchward gravitational collapse of the plate edge. The tectono-stratigraphic complexity exhibited within the Central Andean forearc is likely to be representative of Cordilleran-type margins and would be difficult to recognize in an ancient continental forearc.
Maass, T.; castro Heredia, L. M.; Suarez, F. I.; Fernandez, B.
Hydroelectric power plant operations are heavily influenced by the streamflow forecasts on their basins. In Chile, these forecasts are based on historical observations. However, this approach has reached its limit of quality and reliability, being difficult to adapt to current weather conditions (climate change), to extreme weather conditions, and to ungauged basins. In this work, we evaluated the bias correction of NCEP-CSv2 daily precipitation with the aim of incorporating this forecast into a real-time hydrological forecasting system. Bias correction was performed using two approaches of the Quantile Mapping (QM) method: a) a polynomial fit (APo) applied to the differences between the forecasted and observed cumulative distribution functions (CDFs) for the training period; and b) using a Gamma probability distribution (APb) to fit the forecasted and observed CDFs. The bias correction was applied at two locations in south-central Chile: over the valley and in the Andes mountains. To estimate the CDFs and the QM fitting models in the training period, historical records and data from the CFSv2 Reforecast model (between 1995 and 2009) were used. The bias correction evaluation was done between 2011 and 2014 with the forecast of the CFSv2 model. The uncorrected CFSv2 results show that the mid-term forecasts (six months) have a high correlation (r>0.5) for the first days of the forecast (2 weeks), but an important underestimation in the observed data from both the valley and the mountain. After applying the bias correction (APo or APb), the errors of the corrected forecasts decrease in relation to the uncorrected CFSv2 forecasts, with a noticeable improvement for the first forecasted days (being the APo errors lower than those of the APb). In the long term, and as might be expected, the errors increase: the peak precipitation is underestimated and the null rainfall is overestimated.
Lorenzo, J. M.; Yáñez, G. A.; Vera, E. E.; Sepúlveda, J.
From December 6-21, 2007, we conducted a 3-component, radio-telemetric, seismic survey along a ~ 15-km wide E-W transect in the Central Andes, at a latitude of ~ 22.41° S, centered north of the city of Calama (68.9° W), Chile. The study area is sandwiched between the Central Depression in the west and the Andean Western Cordillera of Chile. Recording stations, nominally spaced at intervals of either 125 or 250 m collected up to 3.5 s of refracted seismic arrivals at maximum source-receiver offsets exceeding 15 km. Ten shothole sources, spaced 2-6 km apart focused energy on the shallow (0-3 km), crustal, Paleogene-age structures. Preliminary, tomographic inversions of refracted first arrivals show the top of a shallow (< 1km), high- velocity (VP, ~5 km/s) crust, deepening sharply eastward to at least 2 km. At the surface, this central basement step correlates to a regionally extensive (> 600 km), strike-slip fault zone known as the Oeste fault. Turning ray densities suggest the base of the overlying velocity gradient unit (VP, 2-4 km/s) dips inwardly from both east and west directions toward the Oeste fault to depths of almost 1 km. Plate reorganization commencing at least by the latter half of the Oligocene led from oblique to more orthogonal convergence between the South American and the Nazca (Farallon) Plates. We interpret previously mapped, older, minor faults as being generated within the right-lateral, orogen-parallel, Oeste strike-slip fault zone, and postdated by Neogene, N-S striking thrust faults. In this context we also interpret that the spatial distribution of velocity units requires an period of extensional activity that may (1) postdate the transpressional strike slip fault activity of the Neogene, (2) be related to a later releasing bend through the translation and interaction of rigid blocks hidden at depth or even (3) be the consequence of inelastic failure from the result of flexural loading.
Moernaut, J.; de Batist, M. A.; Heirman, K.; van Daele, M.; Brümmer, R.; Pino, M.; Urrutia, R.; Wolff, C.; Brauer, A.; Roberts, S.; Kilian, R.
Megathrust (‘giant’) earthquakes in the South-Central Chilean subduction zone (e.g. 1960 earthquake; Mw: 9.5) cause landslides, tsunamis, soil liquefaction, coastal uplift/subsidence, volcanic eruptions, all of which pose a major threat to society. A reliable seismic hazard assessment requires establishing if such mega-events occurred in the past and determining their recurrence pattern. The Lake District (39-42°S) in South-Central Chile, located in the northern half of the 1960 earthquake rupture zone, contains several large, steep-sloped glacigenic lakes with high sedimentation rates, and whose sedimentary deposits are highly susceptible to earthquake-triggered slope instability. To establish the reoccurrence interval of earthquakes during the Late Holocene, we mapped the spatial distribution of seismically-induced sedimentary ‘event’ deposits and structures in each lake using very-high resolution seismic data, and collected a series of short gravity cores and long piston cores. Multi-proxy sedimentary analyses (color, magnetic susceptibility, density, geochemistry, grain size), radiocarbon dating, varve-counting, and tephro-stratigraphy were used to identify ‘event’ deposits in each core and correlate paleoseismic horizons across basins. The sediment sequences investigated contain four main types of earthquake-induced structures: 1) multiple mass-wasting deposits on a single stratigraphic level, which are relicts of a basin-wide, subaqueous slope instability ‘event’; 2) homogenite deposits in the deepest parts of steep basins indicative of lake seiches and tsunamis; 3) fluid-escape structures (e.g. sediment volcanoes), which reflect sudden liquefaction in buried mass-wasting deposits and subsequent vertical fluidization flow; 4) in-situ deformed units (e.g., contorted bedding) in nearly-flat layers, which reflect strong horizontal ground acceleration events. Comparison with historical earthquakes suggests the spatial extent, thickness, nature of
Jessen, Gerdhard L.; Pantoja, Silvio; Gutiérrez, Marcelo A.; Quiñones, Renato A.; González, Rodrigo R.; Sellanes, Javier; Kellermann, Matthias Y.; Hinrichs, Kai-Uwe
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.
Castro Madariaga, Francisca Alejandra; Gómez Garcés, Belén Estefanía; Carrasco Parra, Alicia; Foster, Jennifer
We explore what it means to promote healthy sexuality for incarcerated women. We report upon the experiences of ten inmates in the Female Central Penitentiary of Santiago, Chile, regarding their sexuality within prison. We used a qualitative, descriptive research approach. Individual and semistructured interviews were conducted with women from different sections of the prison over a 2-month period. Participants highlighted the site for conjugal visits, the Venusterio, as a place of privacy and sexual expression between couples from outside prison. Motivated by loneliness, need of protection, and desire for affection, participants enacted alternate gender and sexual identities and sexual orientation. Some previously heterosexual women became 'machos', women taking on dominant masculine identities. Women found a paradoxical freedom to express a malleable and fluid sexual identity, an identity that might not go outside the prison. Informed by Judith Butler's idea of performativity, we argue that women could enact both different gender and sexual identities in search of satisfying their affective and erotic desires while under the duress of incarceration. The findings suggest a need for a more fluid understanding of gender and sexuality, especially for those midwives and nurses who strive to promote sexual health, not only reproductive health.
Corradini, Fabio; Nájera, Francisco; Casanova, Manuel; Tapia, Yasna; Singh, Ranvir; do Salazar, Osval
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.
Lavanderos, L; Pozo, M E; Pattillo, C; Miranda, H
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.
Schnettler, Berta; Lobos, Germán; Orellana, Ligia; Grunert, Klaus; Sepúlveda, José; Mora, Marcos; Denegri, Marianela; Miranda, Horacio
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 < .01); gender, self-reported number of days affected by mental health problems, frequency of supper with the family, the degree of agreement with respect to family being an important source of happiness (p < .05); and family size and frequency of food 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.
Olmos, Viviana L; Habit, Evelyn M
This study describes a new species of Pomphorhynchus collected from Percilia gillissi Girard, 1855 from the Zañartu canal, between the sister basins of the Itata and Laja rivers, in central Chile. Pomphorhynchus moyanoi n. sp. is characterized by an asymmetrical, well-differentiated subspherical bulb and 12-14 longitudinal rows of 13-14 hooks; the third and the fourth hook in each row are stout. Among South American species, P. moyanoi n. sp. shows some similarities to the Chilean species P. yamagutii Schmidt & Hugghins, 1973, but it differs in having a longer neck, larger bulb, and different proboscis armature arrangement. Pomphorhynchus moyanoi n. sp. differs from P. patagonicus Ortubay, Ubeda, Semenas & Kennedy 1991, in the bulb shape (protuberances), number of rows, fourth hook size and basal hook size. Pomphorhynchus moyanoi n. sp. also differs from P. sphaericus in the arrangement of hooks (number of rows and hooks per row), length and width of the proboscis, neck width, and symmetry of the bulb.
Stotz, Wolfgang B.; Aburto, Jaime; Caillaux, Luis M.; González, Sergio A.
Through a systematic study of a stretch of coast in north central Chile, the variety and vertical zonation patterns of the rocky subtidal communities are described, thereby revising apparent uniformity and lack of vertical zonation of the rocky subtidal of southeastern Pacific shores previously reported in the literature. Over the 600 km of coast studied, the following pattern of depth-zonation is described: an upper fringe (lower part of the sublittoral fringe) characterized by barren grounds dominated by calcareous encrusting algae and the sea urchin Tetrapygus niger; an intermediate fringe (upper Infralittoral sub-zone) characterized either by deep barren grounds similar to the former, or kelp beds of Lessonia trabeculata, or an assemblage of suspension feeding organisms, as the big barnacle Austromegabalanus psittacus and/or the tunicate Pyura chilensis; and a deep fringe (Circalittoral sub-zone) dominated by small encrusting or mobile invertebrates. This basic vertical zonation pattern of the shallow rocky subtidal communities seems to be common to most of the temperate coasts of the world. The analysis, first of the occurrence of the general zonation pattern and second of the species composition within the assemblages corresponding to each sub-zone, offers a useful framework for the assessment of the eventual impacts and changes within the shallow rocky subtidal habitat, for example within environmental monitoring programs.
Nelson, A.R.; Manley, W.F.
During the past 6000 years Isla Mocha, a 12 km-long island 30 km off the coast of south-central Chile, experienced a 38 m fall of relative sea level caused primarily by rapid tectonic uplift of the island. As many as 18 raised shorelines (strandlines) record this uplift. Historic accounts of uplift during the great earthquakes (M > 8) of 1835 and 1960 suggest some of the more prominent prehistoric strandlines also emerged during great earthquakes on the interface between the Nazca and South America plates. But the close elevational spacing of strandlines, subdued morphology of strandline beaches, scarcity of exposed bedrock wave-cut platforms, and the extremely high rates of aseismic uplift (ca. 70 mm/yr) of the island since the last great earthquake suggest that many strandlines were raised by aseismic rather than coseismic uplift. Strandline heights and 14 new radiocarbon ages on marine shells show that the present-day uplift rate is more than three times the net rate (ca. 20 mm/yr) of the past 1000 years. The recent high rate probably reflects increased aseismic slip on an inferred thrust fault in the overriding South America plate. Isla Mocha overlies an area of high stress concentration between two major segments of the Chilean subduction zone. The inferred high rate of slip on the thrust fault may be a response to stress changes on the plate interface near the boundary between the segments. ?? 1992.
Riquelme-Bugueño, Ramiro; Silva-Aburto, Jocelyn; Escribano, Rubén; Peterson, William T.; Schneider, Wolfgang
Temporal variability in the daily growth rate (DGR) of the Humboldt Current krill, Euphausia mucronata, was studied in eighteen incubation experiments off the coast of Dichato, central Chile (36.5°S), carried out in 2011-2014. Intermolt period (IMP) was derived from the molting rate method in order to estimate the DGRs. Mean IMP was 9.2 ± 4.8 days (range: 2.9-18.7 d). Overall mean DGR was 0.03 ± 0.13 mm d- 1. DGR showed a dome-shaped pattern, with a higher mean DGR when upwelling was moderate (0.06 ± 0.04 mm d- 1) than intense (0.01 ± 0.00 mm d- 1) or weak (0.01 ± - 0.01 mm d- 1). This dome-shaped trend was observed in chlorophyll-a concentrations (Chla) at similar upwelling regimens. E. mucronata DGR variability was best explained by a generalized linear model which included the contribution of the Equatorial Subsurface Water, temperature, dissolved oxygen and Chla as predictor variables. Results suggest that E. mucronata is better adapted to grow under upwelling conditions when it can take advantage of high biological productivity, although the species growth is not limited when weak upwelling or even downwelling occurs. Analysis of the duration of the upwelling events suggest that E. mucronata growth is limited (shrinking) when upwellings last > 10 days.
Fuentes, Sebastián; Ding, Guo-Chun; Cárdenas, Franco; Smalla, Kornelia; Seeger, Michael
Aconcagua River basin (Central Chile) harbors diverse economic activities such as agriculture, mining and a crude oil refinery. The aim of this study was to assess environmental drivers of microbial communities in Aconcagua River estuarine soils, which may be influenced by anthropogenic activities taking place upstream and by natural processes such as tides and flood runoffs. Physicochemical parameters were measured in floodplain soils along the estuary. Bacteria, Actinobacteria, Alphaproteobacteria, Betaproteobacteria, Pseudomonas, Bacillus and Fungi were studied by DGGE fingerprinting of 16S rRNA gene and ribosomal ITS-1 amplified from community DNA. Correlations between environment and communities were assessed by distance-based redundancy analysis. Mainly hydrocarbons, pH and the composed variable copper/arsenic/calcium but in less extent nitrogen and organic matter/phosphorous/magnesium correlated with community structures at different taxonomic levels. Aromatic hydrocarbons degradation potential by bacterial community was studied. Polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenases genes were detected only at upstream sites. Naphthalene dioxygenase ndo genes were heterogeneously distributed along estuary, and related to Pseudomonas, Delftia, Comamonas and Ralstonia. IncP-1 plasmids were mainly present at downstream sites, whereas IncP-7 and IncP-9 plasmids showed a heterogeneous distribution. This study strongly suggests that pH, copper, arsenic and hydrocarbons are main drivers of microbial communities in Aconcagua River estuarine soils.
Yáñez, Eleuterio; Plaza, Francisco; Silva, Claudio; Sánchez, Felipe; Barbieri, María Ángela; Aranis, Antonio
Artificial neural networks (ANNs) were used to predict landings of anchovy ( Engraulis ringens), common sardine ( Strangomera bentincki), and jack mackerel ( Trachurus murphyi) in central-southern Chile. Twelve environmental variables were considered along with fishing effort (fe) and landing statistics from 1973 to 2012. During external validation, the best models with all of the selected variables gave r 2 values of 90 % for anchovy, 96 % for common sardine, and 88 % for jack mackerel. The models were simplified by considering only fe and sea surface temperature from NCEP/NCAR reanalysis data (SST-NOAA), and very similar fits were achieved (87, 92, and 88 %, respectively). Future SSTs were obtained from the A2 climate change scenario and regionalized using statistical downscaling techniques. The downscaled SSTs were used as input for landings predictions using ANN simplified models. In addition, three scenarios of future fishing efforts (2010-2012 average, average + 50 %, and average - 50 %) were used as the input data for landing simulations. The results of the predictions show a decrease of 9 % in future landings of sardine and an increase of 17 % for jack mackerel when comparing 2015 and 2065 monthly projections. However, no significant differences are shown when comparing the estimated landings for the three fishing effort scenarios. Finally, more integrative and complex conceptual models that consider oceanographic-biophysical, physiological, environmental-resource, and interspecies processes need to be implemented.
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
Heki, K.; Matsuo, K.
as the replacement of air with crustal rock), we modified it so that a smaller density contrast (between crustal rock and sea water) is assumed for vertical deformation of sea floor. After applying the same fan filter, the calculated gravity changes was quite similar to those observed by GRACE. The 2004 SA Earthquake showed distinct postseismic gravity changes (with a time constant of ~0.6 year) characterized by slow increase above the focal area. Past interpretations include the flow of supercritical water around the down-dip end of the fault, Burgers rheology of the low viscosity material in shallow mantle, and afterslip in the down-dip and up-dip extension of the main rupture. Postseismic crustal deformations have been observed with GPS numerous times. In contrast, postseismic gravity changes have been observed just once for the 2004 SA event, and its mechanism has not been well understood. We still have only a few months of GRACE data after the earthquake, too short to separate postseismic and hydrological gravity changes. It is important and interesting to keep investigating slow gravity changes in Central Chile over a long term.
Gilbert, D.; Freundt, A.; Kutterolf, S.; Burkert, C.
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
Janke, Jason R.; Bellisario, Antonio C.; Ferrando, Francisco A.
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
Nina, Nélida; Quispe, Cristina; Jiménez-Aspee, Felipe; Theoduloz, Cristina; Feresín, Gabriela Egly; Lima, Beatriz; Leiva, Elba; Schmeda-Hirschmann, Guillermo
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.
Troncoso-Palacios, Jaime; Elorza, Alvaro A; Puas, German I; Alfaro-Pardo, Edmundo
The Liolaemus nigroviridis group is a clade of highland lizards endemic to Chile. These species are distributed from northern to central Chile, and currently there are no cases of sympatric distribution. This study describes a new species, Liolaemus uniformis sp. n., from this group, and provides a detailed morphological characterization and mitochondrial phylogeny using cytochrome-b. Liolaemus uniformis was found in sympatry with Liolaemus nigroviridis but noticeably differed in size, scalation, and markedly in the color pattern, without sexual dichromatism. This new species has probably been confused with Liolaemus monticola and Liolaemus bellii, both of which do not belong to the nigroviridis group. The taxonomic issues of this group that remain uncertain are also discussed.
Troncoso-Palacios, Jaime; Elorza, Alvaro A.; Puas, German I.; Alfaro-Pardo, Edmundo
Abstract The Liolaemus nigroviridis group is a clade of highland lizards endemic to Chile. These species are distributed from northern to central Chile, and currently there are no cases of sympatric distribution. This study describes a new species, Liolaemus uniformis sp. n., from this group, and provides a detailed morphological characterization and mitochondrial phylogeny using cytochrome-b. Liolaemus uniformis was found in sympatry with Liolaemus nigroviridis but noticeably differed in size, scalation, and markedly in the color pattern, without sexual dichromatism. This new species has probably been confused with Liolaemus monticola and Liolaemus bellii, both of which do not belong to the nigroviridis group. The taxonomic issues of this group that remain uncertain are also discussed. PMID:26877688
Pellicciotti, F.; Helbing, J. F.; Araos, J.; Favier, V.; Rivera, A.; Corripio, J.; Sicart, J. M.
Results from a recent glacio-meteorological experiment on the Juncal Norte glacier, in central Chile, are presented. Melt water is a crucial resource in the Central Andes, as it provides drinking water, water for agriculture and for industrial uses. There is also increasing competition for water use and allocation, as water demands from mining and industry are rising. Assessing water availability in this region and its relation with climatic variations is therefore crucial. The Dry Central Andes are characterised by a climatic setting different from that of the Alps and the subtropical Andes of Bolivia and Peru. Summers are very dry and stable, with precipitation close to zero and low relative humidity. Solar radiation is very intense, and plays a key role in the energy balance of snow covers and glaciers. The main aim of this study is to investigate the glacier-climate interaction in this area, with particular attention devoted to advanced modelling techniques for the spatial redistribution of meteorological variables, in order to gain an accurate picture of the ablation processes typical of these latitudes. During the ablation season 2005/2006, an extensive field campaign was conducted on the Juncal Norte glacier, aimed at monitoring the melt and runoff generation processes on this remote glacier in the dry Andes. Melt rates, runoff at the snout, meteorological variables over and near the glacier, GPS data and glacier topography were recorded over the entire ablation season. Using this extensive and accurate data set, the spatial and temporal variability of the meteorological variables that drive the melt process on the glacier is investigated, together with the process of runoff generation. An energy balance model is used to simulate melt across the glacier, and special attention is devoted to the modelling of the solar radiation energy flux. The components of the energy balance are compared with those of Alpine basins. The validity of parameterisations of the
Bahlburg, H.; Breitkreuz, C.
The geodynamic evolution of the Paleozoic continental margin of Gondwana in the region of the southern Central Andes is characterized by the westward progression of orogenic basin formation through time. The Ordovician basin in the northwest Argentinian Cordillera Oriental and Puna originated as an Early Ordovician back-arc basin. The contemporaneous magmatic arc of an east-dipping subduction zone was presumably located in northern Chile. In the back-arc basin, a ca. 3500 meter, fining-up volcaniclastic apron connected to the arc formed during the Arenigian. Increased subsidence in the late Arenigian allowed for the accomodation of large volumes of volcaniclastic turbidites during the Middle Ordovician. Subsidence and sedimentation were caused by the onset of collision between the para-autochthonous Arequipa Massif Terrane (AMT) and the South American margin at the Arenigian-Llanvirnian transition. This led to eastward thrusting of the arc complex over its back-arc basin and, consequently, to its transformation into a marine foreland basin. As a result of thrusting in the west, a flexural bulge formed in the east, leading to uplift and emergence of the Cordillera Oriental shelf during the Guandacol Event at the Arenigian-Llanvirnian transition. The basin fill was folded during the terminal collision of the AMT during the Oclóyic Orogeny (Ashgillian). The folded strata were intruded post-tectonically by the presumably Silurian granitoids of the "Faja Eruptiva de la Puna Oriental." The orogeny led to the formation of the positive area of the Arco Puneño. West of the Arco Puneño, a further marine basin developed during the Early Devonian, the eastern shelf of which occupied the area of the Cordillera Occidental, Depresión Preandina, and Precordillera. The corresponding deep marine turbidite basin was located in the region of the Cordillera de la Costa. Deposition continued until the basin fill was folded in the early Late Carboniferous Toco Orogeny. The basin
Badilla-Ohlbaum, R; Ginocchio, R; Rodríguez, P H; Céspedes, A; González, S; Allen, H E; Lagos, G E
A survey of copper levels in agricultural soils of central Chile revealed two soil clusters-one with a mean copper level of 162 mg/kg and one with a mean copper level of 751 mg/kg of soil. Samples of soils from both soil clusters were characterized on the basis of physicochemical characteristics, and copper extractability was compared by saturation and CaCl2 extraction as well as an acid-leaching procedure (TCLP). We also measured the copper content of various tissues of tomato (Lycopersicon esculentum) and onion (Allium cepa) crops growing on these soils. Other than copper levels, soils from the two clusters were quite similar, with slightly greater levels of molybdenum and cadmium in the high-copper soils. Within each cluster, extracted copper levels and total soil copper levels were not correlated. However, the three extraction procedures solubilized significantly more copper from the high-Cu soils. Mineralogical characterization of the soil particles and depth profiles of soil metal levels in a subsample of sites suggested that highly insoluble copper ore and mining wastes might account for the high copper levels. Neither total nor extractable copper levels allowed statistical prediction of the levels of copper in plant tissue. The edible tissues of both crops had the same mean copper content, regardless of the copper soil level. However, copper contents of stems and leaves were significantly higher for plants growing on the high-Cu soils. These results show that in these soils, high copper levels are associated with very insoluble copper species and thus low bioavailability of copper to crop plants.
Daniel, Inger; DeGrandpre, Michael; Farías, Laura
The Tubul-Raqui estuary is a coastal system off central Chile at 37°S, adjacent to an active coastal upwelling area, which undergoes rapid changes associated with natural and anthropogenic perturbations. Biogenic greenhouse gas cycling and the gas saturation levels are good indicators of microbial metabolism and trophic status in estuaries. The dissolved greenhouse gases CO2, CH4 and N2O and other biological and chemical variables were spatially recorded in this estuary over two seasons (summer and winter) and over one-half of one tidal cycle. Tidal and spatial variability of these gases indicated they had different origins within the system. Surface waters were always oversaturated in CO2 (up to 578%) and CH4 (up to 6200%) with respect to the atmosphere. But while CO2 seems to come from marine and in situ metabolism, CH4 appears to be more influenced by fluvial and adjacent salt marsh areas. In contrast, N2O was mostly undersaturated and sediments seem to be largely responsible for its consumption. Strong seasonal variability was also observed in CO2 and CH4 fluxes, being tenfold (from -319 to 714 mmol m-2 d-1) and fivefold (from 0.33 to 2.5 mmol m-2 d-1) higher, respectively, in the austral summer compared to winter. In contrast, only small seasonal differences in N2O fluxes were found ranging from -59 to 28 µmol m-2 d-1. These temporal patterns can be explained not only in terms of hydrological and nutrient balances within the system, but also by the influence of wind-driven upwelling processes. Additionally, potential effects of changes in nutrient load and freshwater discharge on net ecosystem metabolism (i.e., autotrophy or heterotrophy) and therefore, on the production/removal of greenhouse gases in this system were explored.
Martínez, Carolina; Rojas, Daniel; Quezada, Matías; Quezada, Jorge; Oliva, Ricardo
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.
Kempf, Philipp; Moernaut, Jasper; Van Daele, Maarten; Vandoorne, Willem; Pino, Mario; Urrutia, Roberto; De Batist, Marc
We present an exceptionally long and continuous coastal lacustrine record of ∼5500 years from Lake Huelde on the west coast of Chiloé Island in south central Chile. The study area is located within the rupture zone of the giant 1960 CE Great Chilean Earthquake (MW 9.5). The subsequent earthquake-induced tsunami inundated Lake Huelde and deposited mud rip-up clasts, massive sand and a mud cap in the lake. Long sediment cores from 8 core sites within Lake Huelde reveal 16 additional sandy layers in the 5500 year long record. The sandy layers share sedimentological similarities with the deposit of the 1960 CE tsunami and other coastal lake tsunami deposits elsewhere. On the basis of general and site-specific criteria we interpret the sandy layers as tsunami deposits. Age-control is provided by four different methods, 1) 210Pb-dating, 2) the identification of the 137Cs-peak, 3) an infrared stimulated luminescence (IRSL) date and 4) 22 radiocarbon dates. The ages of each tsunami deposit are modelled using the Bayesian statistic tools of OxCal and Bacon. The record from Lake Huelde matches the 8 regionally known tsunami deposits from documented history and geological evidence from the last ∼2000 years without over- or underrepresentation. We extend the existing tsunami history by 9 tsunami deposits. We discuss the advantages and disadvantages of various sedimentary environments for tsunami deposition and preservation, e.g. we find that Lake Huelde is 2-3 times less sensitive to relative sea-level change in comparison to coastal marshes in the same region.
Mercerat, E. D.; Nolet, G.; Marot, M.; Deshayes, P.; Monfret, T.
This work focuses on imaging the subducting slab beneath Central Chile using novel inversion techniques based on the adjoint method and accurate wave propagation simulations using the Spectral Elements Method. The study area comprises the flat slab portion of the Nazca plate between 29 S and 34 S subducting beneath South America. We will use a database of regional seismicity consisting of both crustal and deep slab earthquakes with magnitude 3 < Mw < 6 recorded by different temporary and permanent seismological networks. Our main goal is to determine both the kinematics and the geometry of the subducting slab in order to help the geodynamical interpretation of such particular active margin. The Spectral Elements Method (SPECFEM3D code) is used to generate the synthetic seismograms and it will be applied for the iterative minimization based on adjoint techniques. The numerical mesh is 600 km x 600 km in horizontal coordinates and 220 km depth. As a first step, we are faced to well-known issues concerning mesh generation (resolution, quality, absorbing boundary conditions). In particular, we must evaluate the influence of free surface topography, as well as the MOHO and other geological interfaces in the synthetic seismograms. The initial velocity model from a previous travel-time tomography study, is linearly interpolated to the Gauss-Lobatto-Legendre grid. The comparison between the first forward simulations (up to 4 seconds minimum period) validate the initial velocity model of the study area, although many features not reproduced by the initial model have already been identified. Next step will concentrate in the comparison between finite-frequency kernels calculated by travel-time methods with ones based on adjoint methods, in order to highlight advantages and disadvantages in terms of resolution, accuracy, but also computational cost.
Rudloff, A.; Vigny, C.; Ruegg, J. C.; Campos, J.
Three campaigns of Global Positioning System (GPS) measurements were carried out in the Concepcion-Constitucion seismic gap in South Central Chile in 1996, 1999, and 2002. We observed a network of about 40 sites, made of 2 east-west transects roughly perpendicular to the trench ranging from the coastal area to the Argentina border and 1 north-south profile along the coast. Data sets were processed with MIT's GAMIT/GLOBK package. Horizontal velocities have formal uncertainties around 1 to 2 mm/yr in average. Vertical velocities are also determined and have uncertainties around 2 to 5 mm/yr. We find that the convergence between Nazca and South-America plates better matches the pole previously estimated by (Larson et al, 1997) than the Nuvel-1A estimate. Our estimate predicts a convergence of 72 mm/yr at N70 to be compared with Nuvel-1A 80 mm/yr at N79. With respect to stable South America, horizontal velocities decrease from 35 mm/yr on the coast to 14 mm/yr in the Cordillera. Vertical velocities help constraint lithospheric flecture. Partionning of the slightly oblique convergence will be investigated. The gradient of convergent parallel velocities reflects aseismic elastic loading on a zone of about 400 km width. Interestingly enough, this gradient exhibit a linear pattern, marginally compatible with the expected arctangent shape. 70 mm/yr of motion accumulated since the last big event in this area (1835 Earthquake described by Darwin) represent more than 10 m of displacement. Therefore, this area is probably mature for a next large earthquake, the magnitude of which could reach 8.5.
Fuentes, Francisco; Aguirre, Luis; Vergara, Mario; Valdebenito, Leticia; Fonseca, Eugenia
Cenozoic deposits in the Andes of central Chile have been affected by very low-grade burial metamorphism. At about 33°S in the Cuesta de Chacabuco area, approximately 53 km north of Santiago, two Oligocene and Miocene volcanic units form a ca. 1300-m-thick rock pile. The Miocene unit corresponds to a volcanic complex composed of two eroded stratovolcanoes. Secondary mineral assemblages in both units were studied petrographically and using X-ray diffraction and electron microprobe analyses. Most of the igneous minerals are wholly or partially preserved, and the ubiquitous secondary minerals are zeolites and mafic phyllosilicates. The alteration pattern observed is characterized by a lateral zonation in secondary mineralogy related to a lateral increase in temperature but not to stratigraphic depth. The following three zones were established, mainly based on the distribution of zeolites: zone I comprises heulandite, thomsonite, mesolite, stilbite and tri-smectite; zone II contains laumontite, yugawaralite, prehnite, epidote and chlorite; and zone III comprises wairakite, epidote, chlorite, diopside, biotite and titanite. For each zone, the following temperature ranges were estimated: zone I, 100-180 °C; zone II, 180-270 °C; and zone III, 245-310 °C. The alteration episode was characterized by a high Pfluid/ Ptotal ratio (ca. 1.0), although slightly variable, a high geothermal gradient of ca. 160 °C km -1 and fluid pressures below 500 bars. Although temperature was the main control on the mineral zonation, several interrelated parameters, mainly fluid composition, porosity and permeability, were also important. Hot, near neutral to slightly alkaline pH, alkali chloride hydrothermal fluids with very low dissolved CO 2 contents deposited the secondary minerals. The alteration pattern is the result of depositing fluids in outflow regions from a hydrothermal system developed inside a volcanic complex during the Miocene. The hydrothermal system has been eroded to a
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.
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
Schiappacasse, Ignacio; Nahuelhual, Laura; Vásquez, Felipe; Echeverría, Cristian
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.
Sellanes, Javier; Quiroga, Eduardo; Neira, Carlos; Gutiérrez, Dimitri
The course of environmental conditions and shelf macrobenthic communities off Central Chile (˜36°S) during the strong 1997-98 El Niño (EN) event is compared with a subsequent and basically "normal" period (2002-2003). Changes in macrofaunal community, feeding mode structure, and biomass size spectra are contrasted over time with changes in oceanographic and sediment settings, in order to assess intra- and inter-annual changes in faunal composition during both ENSO periods. During EN, there was a decrease in biomass and abundance of species known to be well adapted to organic-rich, oxygen-deficient environments, such as the interface-feeding polychaete Paraprionospio pinnata. On the other hand the abundance of highly mobile, burrowing polychaetes remained unaffected, or even increased in biomass. The decline of P. pinnata lasted several years after the demise of warm conditions, possibly due to negative interactions with those more mobile burrowing polychaetes. The percent contribution of subsurface-deposit feeders to total biomass increased during EN (49.3±12.4% during summer) and declined only in the summer-fall period of 2002-03 (11.1±4.1%). An opposite trend was observed for interface and surface-deposit feeders. From EN to summer-fall 2002-03 (i.e., normal to low oxygen conditions) the size-structure of the macrobenthos switched from a larger to a smaller-sized assemblage. However, biomass was maintained due to successful recruitment and high abundance of both P. pinnata and the squat lobster, Pleuroncodes monodon. Our results suggest that the shelf macrofaunal community structure exhibit fluctuations at various time scales, and that these changes are more pronounced during and after a strong EN event. In such cases, the effects of such an event may be recorded at latitudes as far south as 36°S, with consequences in the biota lasting for many years after the demise of warm conditions.
Henriquez Dole, L. E.; Gironas, J. A.; Vicuna, S.
Given the critical role of the streamflow regime for ecosystem sustainability, modeling long term effects of climate change and land use change on streamflow is important to predict possible impacts in stream ecosystems. Because flow duration curves are largely used to characterize the streamflow regime and define indices of ecosystem health, they were used to represent and analyze in this study the stream regime in the Maipo River Basin in Central Chile. Water and Environmental Assessment and Planning (WEAP) model and the Plant Growth Model (PGM) were used to simulate water distribution, consumption in rural areas and stream flows on a weekly basis. Historical data (1990-2014), future land use scenarios (2030/2050) and climate change scenarios were included in the process. Historical data show a declining trend in flows mainly by unprecedented climatic conditions, increasing interest among users on future streamflow scenarios. In the future, under an expected decline in water availability coupled with changes in crop water demand, water users will be forced to adapt by changing water allocation rules. Such adaptation actions would in turns affect the streamflow regime. Future scenarios for streamflow regime show dramatic changes in water availability and temporal distribution. Annual weekly mean flows can reduce in 19% in the worst scenario and increase in 3.3% in the best of them, and variability in streamflow increases nearly 90% in all scenarios under evaluation. The occurrence of maximum and minimum monthly flows changes, as June instead of July becomes the driest month, and December instead of January becomes the month with maximum flows. Overall, results show that under future scenarios streamflow is affected and altered by water allocation rules to satisfy water demands, and thus decisions will need to consider the streamflow regime (and habitat) in order to be sustainable.
Ely, L. L.; Cisternas, M.; Wesson, R. L.; Lagos, M.
On February 27, 2010 a great M 8.8 earthquake and accompanying tsunami struck the region between Constitución and Concepción in south-central Chile. In the year immediately preceding this event, we described and surveyed deposits from previous tsunamis at several sites in the Concepción region (36.5°-38.5° S. Lat). This research positioned us to document the geomorphic and tectonic effects of the 2010 earthquake and tsunami. Following the 2010 earthquake we quantified the inundation, inland extent, erosion and deposition of the 2010 tsunami at our study sites and compared with those of previous tsunamis. The 2010 tsunami deposits were also utilized to guide the search for repositories where stratigraphic records of multiple paleotsunami deposits are likely to be preserved. The characteristic of the 2010 tsunami were similar to those reported after the penultimate earthquake in the Concepción region, which occurred in 1835. A sand sheet from the 2010 tsunami blanketed sites at Tirua (38.5° S. Lat) and the Andalien River, (36.7° S. Lat), where we had identified preexisting anomalous, laterally-continuous sand sheets that thin landward and are interbedded with coastal marsh deposits. The great similarity between these and the 2010 tsunami sands substantiated our interpretation that they were also left by previous tsunamis. At the Tirua River estuary, the 2010 tsunami sand sheet is underlain by at least three earlier tsunami deposits. This site lies at the boundary between the northern end of the rupture zone from the M 9.5 earthquake in 1960 and the southernmost reports of the 1835 and 2010 tsunamis. Prominent, laterally-continuous bands of these tsunami sands are interbedded with silty peats along the bank of the Tirua River, 0.8 to 1.8 km inland from the coast. Based on buried historic artifacts and testimonies of local survivors, the youngest pre-2010 sand sheet was deposited by the 1960 tsunami. Preliminary radiocarbon and OSL ages on the lower two sand
Montory, Monica; Ferrer, Javier; Rivera, Diego; Villouta, María Valentina; Grimalt, Joan O
The Ñuble River flows through an agricultural area in the central zone of Chile in which different types of fruits are grown. The objective of this study was to identify the levels and source of organochlorine pesticides (OCPs) in the surface waters of the Ñuble River. Surface water samples were collected at 10 sampling points and analyzed for 19 organochlorine pesticides during the dry (spring-summer) and wet (autumn-winter) periods of 2013 and 2014. The results revealed that concentrations of total OCPs in surface waters ranged from 0.12 to 26.28 ng/l. Endosulfan and lindane were the main OCPs in the water. The maximum OCP levels were found in the dry period, while significantly lower concentrations were recorded in the wet period. This indicates that patterns of OCPs have varied in the last 10 years as this study found low concentrations of DDT and metabolites but significantly increased concentrations of α-endosulfan. Given the fact that OCPs were withdrawn from agricultural used many years ago, their presence indicates that they may be still in use clandestinely. Findings of significant concentrations of endosulfan and lindane in this study lead to the conclusion that the chemical fallow practices contribute to runoff into the river and surface water infiltration into groundwater. Because no studies have previously measured OCP levels in agricultural basins in Chile, this study is an important contribution to the knowledge of organochlorine contaminants present in surface water in Chile.
Cordell, D. R.; Unsworth, M. J.; Diaz, D.; Pavez, M.; Blanco, B.
Geodetic data has shown that the surface of the Laguna del Maule (LdM) volcanic field in central Chile has been moving upwards at rates >20 cm/yr since 2007 over a 200 km2 area. It has been hypothesized that this ground deformation is due to the inflation of a magma body at ~5 km depth beneath the lake (2.8 km b.s.l.). This magma body is a likely source for the large number of rhyolitic eruptions at this location over the last 25 ka. A dense broadband magnetotelluric (MT) array was collected from 2009 to 2015 and included data from a geothermal exploration project. MT phase tensor analysis indicates that the resistivity structure of the region is largely three-dimensional for signals with periods longer than 1 s, which corresponds to depths >5 km. The MT data were inverted using the ModEM inversion algorithm to produce a three-dimensional electrical resistivity model which included topography. Four primary features were identified in the model: 1) A north-south striking, 10 km by 5 km, low-resistivity zone (<5 Ωm) northwest of the inflation centre at a depth of ~5 km (2.8 km b.s.l.) is interpreted as a zone of partial melt which may be supplying material via conduits to account for the observed ground deformation; 2) A shallow low-resistivity feature ~400 m beneath the lake surface (1.8 km a.s.l.) and spatially coincident with the inflation centre is interpreted to be a zone of hydrothermal alteration; 3) A thin, low-resistivity feature to the west of LdM at a depth of ~250 m (2.2 km a.s.l.) is interpreted to be the clay cap of a potential geothermal prospect; 4) A large, low-resistivity zone beneath the San Pedro-Tatara Volcanic Complex to the west of LdM at a depth of ~10 km (8 km b.s.l.) is interpreted to be a zone of partial melt. Further MT data collection is planned for 2016 which will expand the current grid of MT stations to better constrain the lateral extent of the observed features and give greater insight into the dynamics of this restless magma system.
Carenzo, Marco; Pellicciotti, Francesca; Helbing, Jakob; Dadic, Ruzica; Burlando, Paolo
In the Aconcagua River Basin, in the dry Andes of central Chile, water resources in summer originate mostly from snow and ice glacier melt. Summer seasons are dry and stable, with precipitation close to zero, low relative humidity and very intense solar radiation. The region's economic activities are dependent on these water resources, but their assessment is still incomplete and an effort is needed to evaluate present and future changes in water from glacier and seasonal snow covers in this area. The main aim of this paper is to simulate glacier melt and runoff from Juncal Norte Glacier, in the upper Aconcagua Basin, using models of various complexity and data requirement. We simulate distributed glacier ablation for two seasons using an energy-balance model (EB) and an enhanced temperature-index model (ETI). Meteorological variables measured at Automatic Weather Stations (AWSs) located on and off-glacier are extrapolated from point observations to the glacier-wide scale. Shortwave radiation is modelled with a parametric model taking into account shading, reflection from slopes and atmospheric transmittance. In the energy-balance model, the longwave radiation flux is computed from Stefan-Boltzmann relationships and turbulent fluxes are calculated using the bulk aerodynamic method. The EB model includes subsurface heat conduction and gravitational redistribution of snow. Glacier runoff is modelled using a linear reservoir approach accounting for the temporal evolution of the system. Hourly simulations of glacier melt are validated against ablation observations (ultrasonic depth gauge and ablation stakes) and runoff measured at the glacier snout is compared to a runoff record obtained from a combination of radar water level measurements and tracer experiments. Results show that extrapolation of meteorological input data, and of temperature in particular, is the largest source of model uncertainty, together with snow water equivalent initial conditions. We explore
Tapia, Fabian J.; Largier, John L.; Castillo, Manuel; Wieters, Evie A.; Navarrete, Sergio A.
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
Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A
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
Reyes-Díaz, M; Alberdi, M; Piper, F; Bravo, L A; Corcuera, L J
Nothofagus dombeyi (Mirb.) Blume and Nothofagus nitida (Phil.) Krasser are closely related evergreen trees native to south central Chile. Nothofagus dombeyi is a pioneer in habitats subject to high daytime irradiances and nighttime freezing temperatures and has a wider altitudinal and latitudinal distribution than N. nitida, which is restricted to more oceanic climates. We postulated that N. dombeyi has a greater cold-acclimation capacity, expressed as a greater capacity to maintain a functional photosynthetic apparatus at low temperatures, than N. nitida. Because cold-acclimation may be related to the accumulation of cryoprotective substances, we investigated relationships between ice nucleation temperature (IN), freezing temperature (FT), and the temperature causing injury to 50% of the leaf tissues (LT(50)) on the one hand, and concentrations of total soluble carbohydrates (TSC), starch and proline on the other hand. Observations were made throughout a seasonal cycle in adults and seedlings in the field and in seedlings in the laboratory under cold-acclimation inductive and non-inductive conditions. In adults, LT(50) values were lower in N. dombeyi than in N. nitida, suggesting that N. dombeyi is the more frost tolerant species. Adults of both species tolerated freezing in autumn and winter but not in spring and summer. In the fall and winter, seedlings of N. dombeyi had a much lower LT(50) than those of N. nitida. Nothofagus nitida seedlings, in autumn and winter, exhibited freezing avoidance mechanisms. Although elevated TSC and proline concentrations may contribute to freezing tolerance in adults of both species, an increase in proline concentration is unlikely to be the dominant frost tolerance response in adults because proline concentrations were higher in N. nitida than in N. dombeyi. In seedlings, however, there were large differences in proline accumulation between species that may account for the difference between them in freezing tolerance. Starch
A complex composed of ultrabasic and basaltic lavas, chert-argillite, arkose and conglomerate was assembled in the coast of north central Chile prior to 220 Ma ago. Three major episodes of deformation and metamorphism have been observed in this area. The first episode of deformation and metamorphism (F/sub 1/) produced a compositional layering (S/sub 1/) and amphibolite facies metamorphism within the formations listed above. This episode of deformation and metamorphism occurred coevally with intrusion of a regionally extensive 220-200 Ma fine grained gabbro and granitic complex. The second episode of deformation and metamorphism locally formed tight, recumbent folds in S/sub 1/ and at least one low angle reverse fault. K-Ar and Rb-Sr ages on units in which F/sub 2/ folds are well developed range between 163 and 140 Ma. A third episode of deformation and low grade metamorphism (F/sub 3/) locally formed upright, open to tight folds with sharp hinges and axial planes that strike north and dip steeply east. Igneous intrusions that were affected by F/sub 3/ yield K-Ar ages between 140 Ma and 126 Ma. Undeformed cross cutting mafic dykes have been dated by K-Ar at 121 Ma. Paleomagnetic samples collected from 19 sites in radioisotopically dated (using the K-Ar and /sup 40/Ar-/sup 39/Ar techniques) Jurassic mafic dykes and plutons in the coastal cordillera of Chile yield mean paleomagnetic poles that are consistent with the average pole from coeval sequences within the South American craton. The paleomagnetic directions are consistent over the latitudinal range and variety of lithologies encompassed by this study. Paleomagnetic results presented here indicate that no major rotation or translation of crustal blocks has been taken place in this part of central Chile since middle Jurassic time.
Elgueta, Sebastian; Moyano, Stella; Sepúlveda, Paulina; Quiroz, Carlos; Correa, Arturo
To investigate pesticide residue concentrations and potential human health risk, a study was conducted in 118 leafy vegetable samples collected in 2014-2015 from the North Central agricultural areas of Chile. The pesticide residues were determined using the multiresidue QuEChERS method by gas chromatography as well as high-performance liquid chromatography. The results indicated that 27% of the total samples contained pesticide residues above the maximum residue limits of each active ingredient. The maximum estimated daily intake obtained for carbon disulphide (CS2), methamidophos, azoxystrobin and cypermethrin were 0.57, 0.07, 0.06 and 0.05 mg kg(-1), respectively, which was higher than their acceptable daily intake. It is concluded that inhabitants of the North Central agricultural area of Chile are not exposed to health risks through the consumption of leafy vegetables with the exception of methamidophos. Nevertheless, the high levels of methamidophos detected in leafy vegetables could be considered a potential chronic health risk.
Barra, Fernando; Gervilla, Fernando; Hernández, Elkin; Reich, Martin; Padrón-Navarta, José Alberto; González-Jiménez, José Maria
La Cabaña peridotite is part of a dismembered ophiolite complex located within the metamorphic basement of the Coastal Cordillera of south-central Chile, and is the only location in Chile were Cr-spinels have been described so far. The La Cabaña peridotite is part of the Western Series unit, which comprises meta-sedimentary rocks, metabasites, and serpentinized ultramafic rocks. This unit has been affected by greenschist-facies metamorphism with reported peak PT conditions of 7.0-9.3 kbar and 380°-420 °C. Within La Cabaña peridotite Cr-spinels are present in two localities: Lavanderos and Centinela Bajo. In Lavanderos, Cr-spinel occurs in small chromitite pods and as accessory/disseminated grains with a porous or spongy texture in serpentinite, whereas in Centinela Bajo Cr-spinel is present as accessory zoned grains in partly serpentinized dunites, and in chromitite blocks. All Cr-spinels display variable degrees of alteration to Fe2+-rich chromite with a variation trend of major elements from chromite to Fe2+-rich chromite similar to those observed in other locations, i.e., an increase in Fe2O3 and FeO, a decrease in Al2O3 and MgO. Cr2O3 content increases from chromite to Fe2+-rich chromite in chromitite pods from Lavanderos and chromitite blocks from Centinela Bajo, but decreases in ferrian chromite zones in accessory grains from Centinela Bajo. The minor element (Ti, V, Zn, Ni) content is mostly low and does not exceed 0.4 wt.%, with the exception of MnO (<0.9 wt.%), which shows a correspondence with increasing degree of alteration. Cr# (Cr/Cr + Al) versus Mg# (Mg/Mg + Fe2+) and Fe3+/Fe3++Fe2+ versus Mg# plots are used to illustrate the Cr-spinel alteration process. Overall, the Cr-spinels from Lavanderos (chromitite pods and disseminated grains) exhibit Cr# values ranging from 0.6 to 1.0, Mg# (Mg/Mg + Fe2+) below 0.5, and (Fe3+/Fe3++Fe2+) <0.4. Cr-spinels from chromitites in Centinela Bajo have Cr# and Mg# values that range from 0.65 to 1.0, and 0
Ruegg, J. C.; Campos, J.; Madariaga, R.; Kausel, E.; de Chabalier, J. B.; Armijo, R.; Dimitrov, D.; Georgiev, I.; Barrientos, S.
Two campaigns of Global Positioning System (GPS) measurements were carried out in the Concepción-Constitución area of Chile in 1996 and 1999. It is very likely that this area is a mature seismic gap, since no subduction earthquake has occurred there since 1835. In 1996, 32 sites were occupied in the range 35°S-37°S, between the Pacific coast of Chile and the Andes near the Chile-Argentina border. In 1999, the network was extended by the installation of 9 new points in the Arauco region whereas 13 points among the 1996 stations were reoccupied. The analysis of this campaign data set, together with the data recorded at eight continuous GPS sites (mostly IGS stations) in South America and surrounding regions, indicates a velocity of about 40 +/- 10 mm/yr in the direction N80-90°S for the coastal sites with respect to stable cratonic South America. This velocity decreases to about 20-25 mm/yr towards the Andes. We interpret this result as reflecting interseismic strain accumulation above the Nazca-South America subduction zone, due to a locked thrust zone extending down to about 60 km depth.
Jaramillo, E.; Contreras, H.; Duarte, C.; Avellanal, M. H.
The tenebrionid beetle Phalerisida maculata Kulzer, the talitrid amphipod Orchestoidea tuberculata Nicolet and the oniscid isopod Tylos spinulosus Dana are semi-terrestrial burrowing species, which coexist on sandy beaches of north central Chile (28-30°S). During the night, these scavengers emerge to make downshore migrations. Given the similarity in niches of these three species (all are known to include macroalgal detritus in their diet) and their relatively high abundance on that beaches, there is the potential for some degree of interaction, both inter- and intraspecific. Field studies were carried out to examine zonation of these burrowing organisms and eventual time and/or space partitioning of locomotor activity during night hours. Locomotor activity on the beach surface was analyzed over 12 h periods during spring and neap tides of September and December 2000, and March 2001. Scavengers moving over the beach surface were captured using pitfall traps buried with their rims flush with the beach surface along a transect extended from the foot of the dunes to the highest levels reached by the swashes. Every 1 h the captured animals in the traps were collected. Locomotor activity was also studied in the laboratory with chambers equipped with infrared recording systems (actographs). Data downloaded from the actographs were graphed to obtain a display of locomotor activity per 15 min interval during the course of the 7 day experiments. Results show space partitioning of burrowed organisms and time partitioning in the locomotor activity of O. tuberculata, T. spinulosus and P. maculata over the beach surface. Circular statistics showed that usually the activity peaks of O. tuberculata were more different from those of P. maculata and T. spinulosus than those of the last two species when compared with each other. Intraspecific differences were also found in the surface locomotor activity, primarily between juveniles and adults of O. tuberculata. Interseasonal
Peng, Zhigang; Hill, David P.; Shelly, David R.; Aiken, Chastity
We examine remotely triggered microearthquakes and tectonic tremor in central California following the 2010 Mw 8.8 Chile earthquake. Several microearthquakes near the Coso Geothermal Field were apparently triggered, with the largest earthquake (Ml 3.5) occurring during the large-amplitude Love surface waves. The Chile mainshock also triggered numerous tremor bursts near the Parkfield-Cholame section of the San Andreas Fault (SAF). The locally triggered tremor bursts are partially masked at lower frequencies by the regionally triggered earthquake signals from Coso, but can be identified by applying high-pass or matched filters. Both triggered tremor along the SAF and the Ml 3.5 earthquake in Coso are consistent with frictional failure at different depths on critically-stressed faults under the Coulomb failure criteria. The triggered tremor, however, appears to be more phase-correlated with the surface waves than the triggered earthquakes, likely reflecting differences in constitutive properties between the brittle, seismogenic crust and the underlying lower crust.
Marot, M.; Monfret, T.; Pardo, M.; Ranalli, G.; Nolet, G.
The region of central Chile offers a unique opportunity to study the links between the subducting Juan Fernandez Ridge, the flat slab, the double seismic zone (DSZ), and the absence of modern volcanism. Here we report the presence and characteristics of the first observed DSZ within the intermediate-depth Nazca slab using two temporary seismic catalogs (Ovalle 1999 and Chile Argentina Seismological Measurement Experiment). The lower plane of seismicity (LP) is located 20-25 km below the upper plane, begins at 50 km depth, and merges with the lower plane at 120 km depth, where the slab becomes horizontal. Focal mechanism analysis and stress tensor calculations indicate that the slab's state of stress is dominantly controlled by plate convergence and overriding crust thickness: Above 60-70 km depth, the slab is in horizontal compression, and below, it is in horizontal extension, parallel to plate convergence, which can be accounted for by vertical loading of the overriding lithosphere. Focal mechanisms below 60-70 km depth are strongly correlated with offshore outer rise bend faults, suggesting the reactivation of preexisting faults below this depth. The large interplane distances for all Nazca DSZs can be related to the slab's unusually cold thermal structure with respect to its age. Since LPs globally seem to mimic mantle mineral dehydration paths, we suggest that fluid migration and dehydration embrittlement provide the mechanism necessary to weaken the rock and that the stress field determines the direction of rupture.
Nielsen, Sven N.
A sequence of Triassic rocks is exposed near the town of Concepción, Chile. These clastic strata are interpreted as the deposits of rivers, lakes, playas, and alluvial fans. The deposits comprise conglomerates, arkosic sandstones, and sand-, silt- and mudstones. Four facies associations comprising eight sedimentary facies can be distinguished. Plant fossils from the sedimentary sequence of the Santa Juana Formation indicate a Carnian age. The flora includes ferns ( Gleichenites, Cladophlebis, Dictyophyllum, Thaumatopteris, Asterotheca, Saportaea) and seed ferns ( Kurtziana, Antevsia, Dicroidium), ginkgophytes ( Sphenobaiera), cycads ( Pseudoctenis), conifers ( Heidiphyllum, Telemachus, Rissikia), and gymnosperms of uncertain affinities ( Linguifolium, Gontriglossa). Two new species are presented: Pseudoctenis santajuanensis and Gontriglossa reinerae.
Muñoz, G; López, Z; Cárdenas, L
The bivalve Perumytilus purpuratus is a common species that is widely distributed throughout rocky intertidal zones in Chile. This bivalve is the first intermediate host for three trematode species: one bucephalid (an undetermined species) and two fellodistomids (Proctoeces lintoni and one undetermined species). A few studies based on morphological comparisons, experimental infection and molecular analyses have been performed to ascertain the taxon (at least at the family level) to which these trematodes belong; yet, there remains no clarification about the specific identity of these trematodes. Therefore, in this study, we compared the V4 region nucleotide sequences of the 18S rRNA of these three sporocyst species, classified as morphotypes, found in P. purpuratus and nine adult trematode species from intertidal fishes that are likely definitive hosts for these parasites. The sequences from two of the sporocyst morphotypes matched with adult trematodes from the intertidal fish: type 1 sporocyst was similar to Prosorhynchoides carvajali (Bucephalidae), with a mean genetic divergence of 0.78%, and type 2 sporocyst was similar to Proctoeces sp. (but not P. lintoni), with 0% genetic divergence. The third species (type 3 sporocyst) was classified to the family Fellodistomidae; however, the sequence from this species differed greatly from the three other fellodistomid species documented in the marine fish of Chile and from other fellodistomids in public databases. Moreover, this morphotype has a particular cercarial morphology that greatly differs from other fellodistomid species described thus far. Therefore, this intriguing trematode remains a mystery.
Milessi, Andrés C.; Sellanes, Javier; Gallardo, Víctor A.; Lange, Carina B.
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.
de Juan, Silvia; Gelcich, Stefan; Ospina-Alvarez, Andres; Perez-Matus, Alejandro; Fernandez, Miriam
Ecosystem-based management implies understanding feedbacks between ecosystems and society. Such understanding can be approached with the Drivers-Pressures-State change-Impacts-Response framework (DPSIR), incorporating stakeholders' preferences for ecosystem services to assess impacts on society. This framework was adapted to six locations in the central coast of Chile, where artisanal fisheries coexist with an increasing influx of tourists, and a set of fisheries management areas alternate with open access areas and a no-take Marine Protected Area (MPA). The ecosystem services in the study area were quantified using biomass and species richness in intertidal and subtidal areas as biological indicators. The demand for ecosystem services was elicited by interviews to the principal groups of users. Our results evidenced decreasing landings and a negative perception of fishermen on temporal trends of catches. The occurrence of recreational fishing was negligible, although the consumption of seafood by tourists was relatively high. Nevertheless, the consumption of organisms associated to the study system was low, which could be linked, amongst other factors, to decreasing catches. The comparison of biological indicators between management regimens provided variable results, but a positive effect of management areas and the MPA on some of the metrics was observed. The prioritising of ecosystem attributes by tourists was highly homogenous across the six locations, with "scenic beauty" consistently selected as the preferred attribute, followed by "diversity". The DPSIR framework illustrated the complex interactions existing in these locations, with weak linkages between society's priorities, existing management objectives and the state of biological communities. Overall, this work improved our knowledge on relations between components of coastal areas in central Chile, of paramount importance to advance towards an ecosystem-based management in the area.
Abarzua, Ana M.; Jarpa, Leonora; Martel, Alejandra; Vega, Rodrigo; Pino, Mario
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
Scalabrino, B.; Ritz, J. F.; Lagabrielle, Y.
The Central Patagonian Cordillera is a unique laboratory to study interaction between oceanic and continental lithospheres during the subduction of an active spreading ridge beneath a continent. The subduction of the South Chile spreading Ridge, which separates the Nazca plate from the Antarctic plate, started ca. 15-14 Ma at the southern tip of Patagonia (55°S latitude). The northwards migration of the Chile Triple Junction induces the subduction of several segments especially around 46°S latitude. There, three segments subducted at ca. 6, 3 and 0.3 Ma, leading to the formation of a large asthenospheric slab-window beneath Central Patagonia. Contemporaneously, the Central Patagonia reliefs are undergoing major glacial events since at least 7 Ma. These events are evidenced to the east of the Central Patagonian morphotectonic front within perched relict surfaces. Inset in these perched glacial surfaces are found mid-Pleistocene glacial valleys, as the Lake General Carrera-Buenos Aires amphitheatre (LGCBA), which formed between 1.1 Ma and 16 ka. We used the relationships between the glacial valleys and the volcanism associated with the asthenospheric slab-window to better constraints the structural evolution of the Patagonian Cordillera related to the subduction of the Chili active spreading Ridge. The present work focused within two well-preserved perched flat surfaces named Meseta del Lago Buenos Aires and Meseta del Cerro Galera: (i) The meseta del Lago Buenos Aires defines a plateau made of interbedded units of tills and lavas dated between 12 Ma and 3 Ma. The top surface of the meseta, ˜2000 meters high is dated at 3 Ma, and is shaped by four NE-SW trending glacial lobes characterized with kettles, lineations and moraines. The glacial valleys are beheaded westwards and define perched valleys 200 to 400 meters higher than the western Cordillera. This suggests recent vertical movement along N160 extensive/transtensive corridor located between the morphotectonic
Thompson, J.M.; Grunder, A.L.; Hildreth, Wes
Hot springs discharging from the active hydrothermal system associated with the Calabozos caldera, Chile, have measured orifice temperatures as high as 98. 5 degree C and calculated geothermometer temperatures as high as 250 degree C. Three types of spring waters can be identified from the chemical analyses: a Na-Cl type, a Na-HCO//3 type and a Na-mixed anion type. Chloride-enthalpy relations indicate that the hydrothermal reservoir water may attain temperatures near 342 degree C and that most spring waters are mixed with cold meteoric water. Despite the proximity of Mesozoic marine gypsum deposits, the Cl/Br weight ratio of the Calabozos spring waters does not appear to indicate that these waters have a significant 'marine' signature. Refs.
Castillo, Miguel E; Molina, Juan R; Rodríguez Y Silva, Francisco; García-Chevesich, Pablo; Garfias, Roberto
Wildfires constitute the greatest economic disruption to Mediterranean ecosystems, from a socio-economic and ecological perspective (Molina et al., 2014). This study proposes to classify fire intensity levels based on potential fire behavior in different types of Mediterranean vegetation types, using two geographical scales. The study considered >4 thousand wildfires over a period of 25years, identifying fire behavior on each event, based on simulations using "KITRAL", a model developed in Chile in 1993 and currently used in the entire country. Fire intensity values allowed results to be classified into six fire effects categories (levels), each of them with field indicators linking energy values with damage related to burned vegetation and wildland urban interface zone. These indicators also facilitated a preliminary assessment of wildfire impact on different Mediterranean land uses and, are therefore, a useful tool to prioritize future interventions.
Ladage, S.; Reichert, C.; Schreckenberger, B.; Block, M.; Bönnemann, C.; Canuta, J.; Damaske, D.; Diaz-Naveas, J.; Gaedicke, C.; Krawczyk, C.; Kus, J.; Urbina, O.; Sepulveda, J.
During the RV SONNE cruise 161 Leg 1 to 5 (October 2001 to January 2002) Sub- duction Processes Off Chile (SPOC) have been investigated using a multi-disciplinary geoscientific approach. Here we report first results of multi channel seismic (MCS) experiments and high-resolution swath bathymetry data from Leg 3, south of Val- paraiso. 24 MCS profiles with a total length of 3670 km were run between 36 S to 4020' S, providing a detailed view of the structures related to the subduction of the Nazca Plate under the Chile Margin. The oceanic crust of the Nazca Plate shows at least three sets of structural trends associated with the Mocha and Valdivia Fractures Zones, the spreading lineations and subduction related horst and graben structures. In the study area the trench is filled with well stratified turbidites up to 2 seconds TWT thick. Along the trench axis a turbidite channel exceeding 80 m relief exists. Several large deep sea fan complexes are developed at the slope toe. Their distributary canyons cut deep into the slope and shelf and can be traced back to major river mouths. The deformation front is coincident with the slope toe; compressional structures of the trench fill are uncommon. The deformation front is curved and offset along strike, caused presumably by collision and indentation of structures of the Nazca Plate. The most remarkable features of the MCS - profiles, yet, are the only very rudimentary developed modern accretionary prism as well as the high variability of the lower slope angles. Lower slope angles locally exceed 10. The continental crust extends seawards to the middle slope and acts as a backstop. Several profiles reveal landward dipping reflectors above the downgoing slab, possibly depicting a subduction channel beneath the slope. Thus, the geometry of the subduction units U a young thick trench fill, only rudimental frontal accretion and a subduction channel U argues for subduction of the bulk of the sediments.
Jorquera, Héctor; Borzutzky, Arturo; Hoyos-Bachiloglu, Rodrigo; García, Alvaro
It has been found that Kawasaki disease (KD) cases diagnosed in Japan, Hawaii and San Diego, USA increase when tropospheric wind patterns arrive from central Asia, suggesting a common, wind-borne causal agent. We analyzed KD cases hospitalized in Santiago, Chile to look for associations with local, regional and large scale meteorological variables. We compiled monthly data of KD incidence rates, local meteorological variables, large scale wind patterns and several El Niño Southern Oscillation (ENSO) indices for 2001-2010; we considered standardized anomalies in all analyses and used linear time series models to account for data autocorrelation. We found that meteorological variables explain 38% of variance in KD rates. A unit increase in northerly wind at 3 lagged months, temperature at 1 and 3 lagged months and monthly change of ENSO 4 index are associated with changes in KD rates of 0.203 (95% CI 0.049-0.358), 0.181 (95% CI 0.014-0.347), 0.192 (95% CI 0.030-0.353) and -0.307 (95% CI -0.458-0.156), respectively. These results are robust when northerly wind level is changed or when a shorter period (2005-2010) is used to estimate model parameters. We found a statistical association of KD at Santiago, Chile with tropospheric, northerly wind patterns suggesting that dust transported from the Atacama Desert could include a causative agent. A novel result is that ENSO dynamics also explain part of KD variability with a decrease in KD when La Niña is dissipating or El Niño is on the rise; hence climate scale dynamics might be taken into account in future studies worldwide - at least as a potential explanatory variable that may confound KD seasonality on a global scale.
Nussbaumer, Samuel U.; García, Juan L.; Gómez, Gabriel; Vega, Rodrigo M.; Gärtner-Roer, Isabelle; Salzmann, Nadine
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
Moernaut, Jasper; Daele, Maarten Van; Heirman, Katrien; Fontijn, Karen; Strasser, Michael; Pino, Mario; Urrutia, Roberto; De Batist, Marc
Understanding the long-term earthquake recurrence pattern at subduction zones requires continuous paleoseismic records with excellent temporal and spatial resolution and stable threshold conditions. South central Chilean lakes are typically characterized by laminated sediments providing a quasi-annual resolution. Our sedimentary data show that lacustrine turbidite sequences accurately reflect the historical record of large interplate earthquakes (among others the 2010 and 1960 events). Furthermore, we found that a turbidite's spatial extent and thickness are a function of the local seismic intensity and can be used for reconstructing paleo-intensities. Consequently, our multilake turbidite record aids in pinpointing magnitudes, rupture locations, and extent of past subduction earthquakes in south central Chile. Comparison of the lacustrine turbidite records with historical reports, a paleotsunami/subsidence record, and a marine megaturbidite record demonstrates that the Valdivia Segment is characterized by a variable rupture mode over the last 900 years including (i) full ruptures (Mw ~9.5: 1960, 1575, 1319 ± 9, 1127 ± 44), (ii) ruptures covering half of the Valdivia Segment (Mw ~9: 1837), and (iii) partial ruptures of much smaller coseismic slip and extent (Mw ~7.5-8: 1737, 1466 ± 4). Also, distant or smaller local earthquakes can leave a specific sedimentary imprint which may resolve subtle differences in seismic intensity values. For instance, the 2010 event at the Maule Segment produced higher seismic intensities toward southeastern localities compared to previous megathrust ruptures of similar size and extent near Concepción.
Piquer, Jose; Berry, Ron F.; Scott, Robert J.; Cooke, David R.
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.
Atwater, B.F.; Nunez, H.J.; Vita-Finzi, C.
Intertidal deposits show net Late Holocene emergence at three sites along the Pacific coast near Maulli??n and Carelmapu, Chile (latitude 41.6-41.7??S.). The maximum amount of net emergence is ca. 1 m in the past 1500 years and ca. 2 1 2 m in the past 4000 years. Emergence probably would have prevailed at a fourth site near Maulli??n were the site not underlain by easily compacted deposits; this site shows slight (< 1 m) net submergence in the past 3000 years. Despite net emergence, all four sites underwent 1-2 m of submergence from tectonic subsidence during a magnitude-9.5 earthquake in 1960, and two of the sites show evidence for earlier submergence events of Late Holocene age. The net emergence is probably due to some combination of cyclic uplift from elastic strain accumulation between earthquakes and monotonic uplift from postglacial loading of the Pacific Ocean floor. The small amount of the net emergence shows that neotectonics has had little net impact on Holocene relative sea level in part of the focal region of the largest earthquake recorded by seismograph. ?? 1992.
Vicuna, S.; Melo, O.; Meza, F. J.; Alvarez, P.; Maureira, F.; Sanchez, A.; Tapia, A.; Cortes, M.; Dale, L. L.
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
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. Five bacterial isolates
Altamirano, Adison; Cely, Jenny Paola; Etter, Andrés; Miranda, Alejandro; Fuentes-Ramirez, Andres; Acevedo, Patricio; Salas, Christian; Vargas, Rodrigo
Ulex europaeus (gorse) is an invasive shrub deemed as one of the most invasive species in the world. U. europaeus is widely distributed in the south-central area of Chile, which is considered a world hotspot for biodiversity conservation. In addition to its negative effects on the biodiversity of natural ecosystems, U. europaeus is one of the most severe pests for agriculture and forestry. Despite its importance as an invasive species, U. europaeus has been little studied. Although information exists on the potential distribution of the species, the interaction of the invasion process with the spatial dynamic of the landscape and the landscape-scale factors that control the presence or absence of the species is still lacking. We studied the spatial and temporal dynamics of the landscape and how these relate to U. europaeus invasion in south-central Chile. We used supervised classification of satellite images to determine the spatial distribution of the species and other land covers for the years 1986 and 2003, analysing the transitions between the different land covers. We used logistic regression for modelling the increase, decrease and permanence of U. europaeus invasion considering landscape variables. Results showed that the species covers only around 1 % of the study area and showed a 42 % reduction in area for the studied period. However, U. europaeus was the cover type which presented the greatest dynamism in the landscape. We found a strong relationship between changes in land cover and the invasion process, especially connected with forest plantations of exotic species, which promotes the displacement of U. europaeus. The model of gorse cover increase presented the best performance, and the most important predictors were distance to seed source and landscape complexity index. Our model predicted high spread potential of U. europaeus in areas of high conservation value. We conclude that proper management for this invasive species must take into account
Olivares, M. A.
Hydropower accounts for about 50% of the installed capacity in Chile's Central Interconnected System (CIS) and new developments are envisioned in the near future. Large projects involving reservoirs are perceived negatively by the general public. In terms of operations, hydropower scheduling takes place at monthly, weekly, daily and hourly intervals, and operations at each level affect different environmental processes. Due to its ability to quickly and inexpensively respond to short-term changes in demand, hydropower reservoirs often are operated to provide power during periods of peak demand. This operational scheme, known as hydropeaking, changes the hydrologic regime by altering the rate and frequency of changes in flow magnitude on short time scales. To mitigate impacts on downstream ecosystems, operational constraints -typically minimum instream flows and maximum ramping rates- are imposed on hydropower plants. These operational restrictions limit reduce operational flexibility and can reduce the economic value of energy generation by imposing additional costs on the operation of interconnected power systems. Methods to predict the degree of hydrologic alteration rely on statistical analyses of instream flow time series. Typically, studies on hydrologic alteration use historical operational records for comparison between pre- and post-dam conditions. Efforts to assess hydrologic alteration based on future operational schemes of reservoirs are scarce. This study couples two existing models: a mid-term operations planning and a short-term economic dispatch to simulate short-term hydropower reservoir operations under different future scenarios. Scenarios of possible future configurations of the Chilean CIS are defined with emphasis on the introduction of non-conventional renewables (particularly wind energy) and large hydropower projects in Patagonia. Both models try to reproduce the actual decision making process in the Chilean Central Interconnected System
Neira, Sergio; Arancibia, Hugo
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.
Cisternas, M.; Lagos, M.; Srinivasalu, S.
A stratigraphic sequence at Cocotue Bay, Chiloe Is., south-central Chile, containing both earthquake-triggered debris flows and tsunami deposits, yields an earthquake history that likely includes the giant earthquakes and tsunamis inferred previously from a combination of geology, ecology, and written records in south-central Chile (AD ~1000, ~1300, 1575 and 1960). However, the Cocotue sequence also contains evidence for at least four additional earthquakes and tsunamis that are intermediate in age and perhaps lesser in size. The most recent of the additional earthquakes recorded at Cocotue probably corresponds to the poorly understood Chilean earthquake and associated trans-Pacific tsunami of 1837. The tsunami, though small on the Chilean coast, ran as high as 6 m in Hawaii and flooded fields in Japan. At Cocotue, the 1837 earthquake, like other three earlier events, is probably represented by both a debris-flow deposit and a tsunami deposit. To study the sedimentary record of intermediate and lesser events is important because this is the more probable kind of event to occur in the near future of south-central Chile. Research funded by Proyecto Fondecyt 1060227
Suárez, M.; de la Cruz, R.; Troncoso, A.
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.
Hoganson, J.W.; Ashworth, A.C.
Cold-adapted beetles colonized the lowlands of the Lake Region of south-central Chile following the retreat of glaciers from their maximum extent at about 19,500 yr B.P. The beetle fauna from 18,000 to 14,000 yr B.P. was characterized by species of moorland habitats. This fauna was species-poor compared to later faunas of the postglacial interval. By 14,000 yr B.P. arboreal species were replacing species of open habitats, reflecting a change toward a warmer climate. By about 12,500 yr B.P. fossil beetle assemblages consisted entirely of rain forest species. The fauna of the postglacial interval was about five times as species-rich as that of the glacial interval. The change in species composition and greater diversity of the beetle fauna was produced by an increase in mean annual temperature estimated to be about 4??-5??C. This was the last major climatic change to affect profoundly the biota of the middle latitudes of South America. The fossil beetle assemblages do not imply a reversal to a colder climate at the time of the European Younger Dryas interval between 11,000 and 10,000 yr B.P. ?? 1992.
Pfeiffer, Marco; Le Roux, Jacobus P.; Solleiro-Rebolledo, Elizabeth; Kemnitz, Helga; Sedov, Sergey; Seguel, Oscar
At the Tongoy palaeobay in north-central Chile, a series of beach ridges developed during seaward progradation that took place after the MIS 11 sea-level highstand (412 ka). The microrelief left by this succession of beach ridges has been well preserved from erosion due to the development of a calcrete (petrocalcic horizons), which was resistant to the chemical and physical weathering that characterized the area during humid phases of the late Pleistocene and middle Holocene. Macro- and micro-morphological analysis shows that the calcrete is of pedogenic origin and formed during two stages: in the first stage a massive (beta) calcrete developed, followed during the second stage by a laminar (alpha) calcrete. Each event in the development of the calcrete was intimately related to the foregoing process, mainly due to changes in the permeability of the profile horizons. During the first stages of development, organisms played an important role in the precipitation of calcite, which made the calcrete less permeable and favored the accumulation of ponded water during the wet season. As a result of this increased humidity, calcium carbonate with a laminar structure was precipitated. The development of the calcrete was also intimately associated with the evolution of the drainage network, which is characterized by a trellis pattern of tributaries parallel to the beach ridges. This study demonstrates the importance of soil genesis in the geomorphological evolution of landscapes.
Medellín-Mora, Johanna; Escribano, Ruben; Schneider, Wolfgang
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 mm) decreased in abundance, being replaced by larger sized (>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.
Torres-Díaz, Cristian; Ruiz, Eduardo; González, Fidelina; Fuentes, Glenda; Cavieres, Lohengrin A.
Background and Aims The endemic tree Nothofagus alessandrii (Fagaceae) has been historically restricted to the coastal range of Region VII of central Chile, and its forests have been increasingly destroyed and fragmented since the end of the 19th century. In this study, the patterns of within- and among-population genetic diversity in seven fragments of this endangered narrowly endemic tree were examined. Methods Allozyme electrophoresis of seven loci of N. alessandrii was used to estimate genetic diversity, genetic structure and gene flow. Key Results High levels of genetic diversity were found as shown by mean expected heterozygosity (He = 0·182 ± 0·034), percentage of polymorphic loci (Pp = 61·2 %), mean number of alleles per locus (A = 1·8) and mean number of alleles per polymorphic locus (Ap = 2·3). Genetic differentiation was also high (GST = 0·257 and Nm = 0·7). These values are high compared with more widespread congeneric species. Conclusions Despite its endemic status and restricted geographical range N. alessandrii showed high levels of genetic diversity. The observed patterns of diversity are explained in part by historical processes and more recent human fragmentation. PMID:17513870
Araneda, A.; Larocque-Tobler, I.; Torrejon, F.; Grosjean, M.; Jana-Pinninghoff, P.; Ortega, C.; Urrutia, R.
Quantitative climate reconstructions of the last two millennia are a fundamental issue in order to compare the current trends in climate observed nowadays. At global scale most of the climate reconstructions have been developed for the Northern Hemisphere, while for the Southern Hemisphere quantitative reconstructions are very rare and very limited geographically. The recognition of such disparity has generated among other research initiatives the LOTRED-SA Long-Term climate Reconstruction and Dynamics of (southern) South America, a collaborative, high-resolution multi-proxy approach within the framework of the IGBP-PAGES program. In this context our work presents the results of a 50-lakes training set in Central-Southern Chile developed with the aim to generate a basis for quantitative chironomid-inferred temperature reconstructions for this part of the continent. Chironomids (Insecta: Diptera) are aquatic insects that develop a great proportion of their life cycle as larvae in aquatic ecosystems. Several studies, developed mainly in the Northern Hemisphere, have proven their usefulness in reconstructing past climate due to the larvae's relationship to temperature. The training set developed here includes lakes located between 34 and 48 S, covering a broad temperature (as latitudinal) gradient. The surface (0-1 cm) sediment of each lake was sampled and chironomids, organic matter and nutrient were analyzed. Water analyses included the measurement of 10 variables (AirT, WBT, WST, N-tot, P-tot, Fe, Na, pH among others). In order to identify the most important variables explaining the highest variance in the chironomid assemblages, ordinations analyses were performed. A preliminary DCA analysis indicated, according to the length of gradients smaller than 3 STD, that a linear model was more appropriate for further analysis. Hence a RDA analysis was applied to the environmental and species data, indicating that the most important variables to determine chironomid
Bozkurt, Deniz; Rojas, Maisa; Valdivieso, Jonás; Falvey, Mark
We have assessed the impact of projected increases in temperature and decreased precipitation on variability and potential changes in hydroclimate regimes and extremes over Andean basins in the central-southern Chile (~30-40S). The altitude of the southern Andes in the study area has an average altitude of 5000 m in the north that decreases to 3000 m at the southern edge. Climatically the region has a Mediterranean-like climate with mainly winter precipitation that gradually increases southwards, from around 300 mm/yr to 1000 mm/yr. The region is home to most of the population in Chile (~10 mil. inhabitants), it has fertile and productive agriculture land, as well as hydro-electrical power plants. During the 20th Century the region has experienced a decreasing precipitation trend imbedded in important interannual and decadal scale variability. We have used gridded observed daily precipitation and temperatures to drive and validate the VIC macro-scale model over the region of interest at 0.25 x 0.25 degree resolution. Historical (1960-2005) and projected (RCP8.5, 2006-2099) daily precipitation and temperatures from 28 CMIP5 models are adjusted via a transfer function based on the gridded observed daily precipitation and temperature data. Adjusted time series are then used to drive the VIC model in order to present climate change projections. The hydrological model simulations foresee that drying is robust in the models and total annual runoff will decrease in the future (40-45% by the end of the century). Center timing of runoff tends to shift to earlier days (3-5 weeks by the end of the century). In some areas over the Andes winter runoff is projected to increase due to upward movement of zero isotherm. Moreover, reductions in the amount of snowpack and accelerated snowmelt lead to more pronounced increase in winter evapotranspiration over the same areas. The simulated 12-months Standardized Runoff Index (SRI) clearly shows severe persistent hydrological droughts
Suárez, Manuel; De La Cruz, Rita; Fanning, Mark; Novas, Fernando; Salgado, Leonardo
Three Tithonian concordant U-Pb SHRIMP zircon ages of 148.7 ± 1.4, 147.9 ± 1.5 and 147.0 ± 1.0 from tuffs intercalated in a clastic sedimentary succession with exceptional dinosaur bones including the new taxon Chilesaurus diegosuarezi gen. et sp. nov. exposed in central Chilean Patagonia (ca. 46°30'S) are reported herein. The fossiliferous beds accumulated in a synvolcanic fan delta reaching a shallow marine basin as indicated by glauconite present in some of the beds, and coeval with the beginning of the transgression of the Aysén Basin.
Quade, Jay; Rech, Jason A.; Betancourt, Julio L.; Latorre, Claudio; Quade, Barbra; Rylander, Kate Aasen; Fisher, Timothy
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).
Rossel, V.; De La Fuente, A.
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
González, R. R.; Quiñones, R. A.
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
Lavandero, B; Miranda, M; Ramírez, C C; Fuentes-Contreras, E
Landscape genetics have been particularly relevant when assessing the influence of landscape characteristics on the genetic variability and the identification of barriers to gene flow. Linking current practices of area-wide pest management information on pest population genetics and geographical barriers would increase the efficiency of these programs. The woolly apple aphid, Eriosoma lanigerum (Hausmann), an important pest of apple orchards worldwide, was collected on apple trees (Malus domestica Borkh) from different locations in a 400 km north-south transect trough central Chile. In order to determine if there was population structure, diversity and flow were assessed. A total of 215 individuals from these locations were analysed using Inter Simple Sequence Repeat (ISSR) markers. Four ISSR primers generated a total of 114 polymorphic loci. The percentage of molecular variation among locations was 18%. As the algorithm used by structure may be poorly suited for inferring the number of genetic clusters in a data set that has an IBD relationship, the number of genetic clusters in the samples was also analyzed using a Bayesian clustering method implemented in software Baps version 4.14. We inferred the presence of four genetic clusters in the study region. Clustering of individuals followed a pattern explained by some geographical barriers. Using partial Mantel tests, we detected barriers to gene flow other than distance, created by a combination of main rivers and mountains. Although landscape genetics are rarely used in pest management, our results suggest that these tools may be suitable for the design of area-wide pest management programs.
Pantoja, S.; Gutiérrez, M. H.; Ampuero, P.; Tejos, E.
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 degradation capability of the coastal ecosystem off central Chile. Extracellular enzymatic hydrolysis in seawater was dominated by aminopeptidase activity on substrate MCA-leu (1.2 to 182 nM h-1), which surpassed that of substrates MUF-glu (0.08-61 nM h-1) and MUF-cel (0.15-6.8 nM h-1), with the fastest rates measured during spring-summer. In riverine waters, extracellular enzymatic hydrolysis remained within the range of 45 to 131 nM h-1 for MCA-leu and ca. 20 nM h-1 for glucosidic substrates, year-round. Contrary to the observed for the marine water column, surface sediment extracellular enzymatic hydrolysis of MCA-leu (0.04 to 6.13 nmol gdw-1 h-1) was in the same order of magnitude as the rates observed for MUF-cel (0.004 to 2.58 nmol gdw-1 h-1) and MUF-glu (0.007 to 10.5 nmol gdw-1 h-1). Moreover, hydrolysis 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 construct a carbon budget for winter and spring-summer in the coastal area adjacent to the Itata River discharge. The comparison of fluxes evidenced a deficit of photosynthetic carbon to fuel extracellular hydrolysis in the water column during both periods (winter 20% and spring-summer 35%). We estimated that the Itata River is a feasible source of dissolved organic carbon, specially during winter, in the form of macromolecules, although non-focal sources may be also significant for the area.
Pantoja, S.; Gutiérrez, M. H.; Ampuero, P.; Tejos, E.
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.
Geersen, Jacob; Scholz, Florian; Linke, Peter; Schmidt, Mark; Lange, Dietrich; Behrmann, Jan H.; Völker, David; Hensen, Christian
Seafloor seepage of hydrocarbon-bearing fluids has been identified in a number of marine fore arcs. However, temporal variations in seep activity and the structural and tectonic parameters that control the seepage often remain poorly constrained. Subduction zone earthquakes, for example, are often discussed to trigger seafloor seepage but causal links that go beyond theoretical considerations have not yet been fully established. This is mainly due to the inaccessibility of offshore epicentral areas, the infrequent occurrence of large earthquakes, and challenges associated with offshore monitoring of seepage over large areas and sufficient time periods. Here we report visual, geochemical, geophysical, and modeling results and observations from the Concepción Methane Seep Area (offshore Central Chile) located in the rupture area of the 2010 Mw. 8.8 Maule earthquake. High methane concentrations in the oceanic water column and a shallow subbottom depth of sulfate penetration indicate active methane seepage. The stable carbon isotope signature of the methane and hydrocarbon composition of the released gas indicate a mixture of shallow-sourced biogenic gas and a deeper sourced thermogenic component. Pristine fissures and fractures observed at the seafloor together with seismically imaged large faults in the marine fore arc may represent effective pathways for methane migration. Upper plate fault activity with hydraulic fracturing and dilation is in line with increased normal Coulomb stress during large plate-boundary earthquakes, as exemplarily modeled for the 2010 earthquake. On a global perspective our results point out the possible role of recurring large subduction zone earthquakes in driving hydrocarbon seepage from marine fore arcs over long timescales.
Pavez, C.; Tapia, F.; Comte, D.; Gutiérrez, F.; Lira, E.; Charrier, R.; Benavente, O.
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
Pavez Orrego, Claudia; Tapia, Felipe; Comte, Diana; Gutierrez, Francisco; Lira, Elías; Charrier, Reynaldo; Benavente, Oscar
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- Energía Andina (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. 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 local control for fluid mobility. This geometry coincides with surface hydrothermal manifestations and with available geochemical information of the area, which allowed us to generate a
Marot, Marianne; Monfret, Tony; Gerbault, Muriel; Nolet, Guust; Ranalli, Giorgio; Pardo, Mario
The Central Chilean subduction zone (27-35°S) is host to a multitude of unexplained phenomena, all likely linked to one another. Here, the 35 Ma oceanic Nazca plate is subducting beneath South America with a well developed, highly seismic flat slab, very well correlated with the subducting Juan Fernandez seamount Ridge (JFR) track, and also with the absence of volcanism at the surface. The upper plate, currently under compression, is composed of a series of accreted terranes of various origins and ages. Although no general consensus on the formation of this flat slab has been yet achieved, there may have been influence of overthickened oceanic crust, delayed eclogitization and consequent fluid retain within the slab, and slab suction due to the high convergence rate with the thick Rio de Plata craton. Therefore, the main questions we address are: Does the slab dehydrate along the flat subducting segment? If so, how hydrated is the slab, at what depth does slab dehydration occur, where are the fluids transported to, and where are they stored? Is magmatism still active beneath the now inactive arc? Are accreted terranes and suture zones important attributes of this subduction zone? Do they possess their own mantle entities? To answer these questions, we analyzed recorded local seismicity and performed regional 3D seismic tomography for Vp and Vs. Combining seismic tomography with 2D instantaneous thermo-mechanical modeling for the regions of flat and normal subduction, we predict rock compositions for these two regions based on published mineral and rock elastic properties. Here, we present a comparison between the normal subduction zone to the south, reflecting typical and expected features, and the flat slab region to the north, exhibiting heterogeneities. Our results agree with other studies for a dry and cold continental mantle above the flat slab. We distinguish the Cuyania terrane with overthickened crust and/or abnormal mantle beneath it. We notice that the
Völker, David; Stipp, Michael
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.
Parada, Carolina; Colas, Francois; Soto-Mendoza, Samuel; Castro, Leonardo
An individual-based model (IBM) of anchoveta ( Engraulis ringens) larvae was coupled to a climatological hydrodynamic (Regional Oceanic Modeling System, ROMS) model for central-southern Chile to answer the question as to whether or not across- and alongshore transport off central-southern Chile enhances retention in the spawning areas during the winter and summer reproductive periods, using model-based pre-recruitment indices (simulated transport success to nursery areas). The hydrodynamic model validation showed that ROMS captures the mean Seas Surface Temperature and Eddie Kinetic Energy observed in satellite-based data over the entire region. The IBM was used to simulate the transport of eggs and larvae from spawning zones in central Chile (Constitución, Dichato, Gulf of Arauco and Lebu-Corral) to historical nursery areas (HRZ, region between 35°S and 37°S). Model results corroborated HRZ as the most successful pre-recruitment zone (particles originated in the Dichato and Gulf of Arauco spawning areas), as well as identifying Lebu-Corral as a zone of high retention with a high associated pre-recruitment index (particles originated in the Lebu-Corral spawning zone). The highest pre-recruitment values were mainly found in winter. The Constitución and Dichato spawning zones displayed a typical summer upwelling velocity pattern, while the Gulf of Arauco in summertime showed strong offshore and alongshore velocity components. The Lebu-Corral region in winter presented important near-surface cross-shore transport towards the coast (associated with downwelling events), this might be one of the major mechanisms leading to high retention levels and a high pre-recruitment index for Lebu-Corral spawning zone. The limitations of the modeling approach are discussed and put into perspective for future work.
A paleomagnetic and magnetic fabric study of the Illapel Plutonic Complex, Coastal Range, central Chile: Implications for emplacement mechanism and regional tectonic evolution during the mid-Cretaceous
Ferrando, Rodolfo; Roperch, Pierrick; Morata, Diego; Arriagada, César; Ruffet, Gilles; Córdova, Maria Loreto
The Illapel Plutonic Complex (IPC), located in the Coastal Range of central Chile (31°-33° S), is composed of different lithologies, ranging from gabbros to trondhjemites, including diorites, tonalites and granodiorites. U/Pb geochronological data shows that the IPC was amalgamated from, at least, four different magmatic pulses between 117 and 90 Ma (Lower to mid-Cretaceous). We present new paleomagnetic results including Anisotropy of Magnetic Susceptibility (AMS) from 62 sites in the plutonic rocks, 10 sites in country rocks and 7 sites in a mafic dyke swarm intruding the plutonic rocks.
Sellanes, Javier; Zapata-Hernández, Germán; Pantoja, Silvio; Jessen, Gerdhard L.
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
Gutierrez, F. J.; Payacán, I.; Gelman, S. E.; Bachmann, O.; Creative Physical Petrology Team
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
Aguirre, L.; Feraud, G.; Fuentes, F.; Delbar, M.; Morata, D.
Dating low to very low-grade burial metamorphic assemblages is often difficult because of (1) few mineral phases compositionally suitable to apply the 40Ar/39Ar and K-Ar methods, and (2) small amount in which these phases are commonly found. K-feldspar adularia, sericitic mica, and celadonite are the best known K-bearing secondary minerals. We present some successful attempts to analyse two distinct secondary phases from a same volcanic formation that allow to test the validity of the measured ages. These ages have been also compared with the crystallisation age of the volcanic rocks in which the secondary phases were lately developed. Adularia and sericite were selected from basic lava flows from a 3 to 13 km thick Cretaceous sequence from the Coastal Range of central Chile, at two different locations: the Bustamante Hill (west from Santiago), and the Cordón de Chacana, c. 80 km further north. Adularia came from a low-variance assemblage with pumpellyite, chlorite and low-albite contained in amygdules whereas sericite was present in milky-white strongly sericitized plagioclase crystals. While small clusters of rare fresh plagioclase grains from lava flows from Bustamante and Chacana displayed concordant plateau ages 119.4 ± 2.4 (2 sigma) and 118.7 ± 0.6 Ma, respectively, the adularia from the same formations gave sensibly younger ages around 94 Ma (high temperature steps), and 96.8 ± 0.2 Ma (plateau age) in Bustamante and Chacana, respectively. Sericite ages were measured in situ into single crystals of strongly transformed plagioclases. The relative proportion of sericite and plagioclase corresponding to each degasing step was monitored by measuring the Ca/K ratio (deduced from 37ArCa/39Ar_K). While intermediate ages were measured on some sericite of both sites (corresponding to a variable but permanent contribution of plagioclase on each step), a plateau age of 97.0 ± 1.6 Ma (concordant with adularia) could be obtained on a strongly sericitized plagioclase
Kuhn, Philipp P.; Echtler, Helmut; Littke, Ralf; Alfaro, Guillermo
The Arauco basin is part of the coastal forearc domain in South-Central Chile. During its evolution since the Late Cretaceous it was subject to multiple deposition cycles and the erosion of lower bathyal to beach and lagoon sediments. These different environments were established in alternating accretional and erosive subduction tectonic settings along the South Andean active margin. Whereas the general development is well understood, inconsistencies arise regarding the origin of the high thermal maturity of Eocene coals and the estimates of vertical movements of the whole area during the Cenozoic. Thermal modelling of this forearc basin provides new insights regarding its thermal evolution and evaluation of the magnitudes of subsidence and inversion. Results are based on the analysis of coal samples from surface outcrops, mines and drill cores of ten onshore wells from ENAP/Sipetrol. Newly derived vitrinite reflectance (VR r) measurements indicated a temperature in the range of 135-150 °C for the oldest sediment unit of the Arauco basin, which was reached in post Eocene times. Furthermore, 1D basin modelling techniques indicate scenarios that could explain the coalification values in the basin's sediments. The models were calibrated against VR r data from drill core samples supplied by ENAP/Sipetrol. A Miocene and an Oligocene subsidence/inversion scenario were considered, while neither could be securely discarded based on the modelling results. Furthermore, it can be shown that the current thermal maturity was not reached by an increased heat flow (HF) or a deep subsidence only. Consequently, a structural inversion accompanied by the erosion of ~ 3.0 ± 0.4 km depending on the locality in combination with a high HF of ~ 64 ± 4 mW/m 2 is the best explanation of the available data. The HF, which is high for a forearc setting, can be attributed to the increased temperature of the relatively young subducted Nazca Plate and an additional influence of ascending hot
Krawczyk, C. M.; Onshore Nvr Party, Spoc
Between 36 and 39 S, the multi-disciplinary offshore project SPOC (Subduction Processes Off Chile) was extended landwards in November 2001 by different active and passive seismic experiments, with the zone of seismic coupling, generally located between 20-40 km depth, as the prime target. Here, we report the first results from the near-vertical incidence reflection (NVR) seismic experiment component that was designed to image that part of the subduction zone between the S-America and over- riding Nazca-Plate that is located in the offshore-onshore transition zone. The NVR profile was located at 37 15`S. Covering the westernmost part of a long E-W refrac- tion seismic line (one amongst three), the profile spread was 54 km long, with three sections of 18 km length each, and extended from the coast in the west to the east. 180 geophone-groups were deployed with 100 m spacing which recorded the offshore pro- file shot by the R/V SONNE with the airgun array. Furthermore, 2 small shots in the Pacific Ocean (50 kg and 25 kg charge), 11 small shots (75 kg charge) at 7 different lo- cations within the onshore reflection seismic line, and 1 shot (150 kg charge) ca. 22.5 km east of the active spread were shot. This active NVR-experiment thereby resulted in a 45 km long 2-fold CDP line, and single-fold coverage along 72 km profile length. The preliminary data processing of single shots gives an image of different reflection bands in the upper and middle crust. On the entire profile, a 1 s TWT thick strong reflection band is observed between 3 and 4 s TWT, which shows almost no dip. On the western half of the profile, prominent reflections dip eastward from ca. 6 s TWT down to ca. 8 s TWT. Finally, in the central part of the seismic reflection profile, some relatively weaker reflections are found between 10 to 14 s TWT. All theses eastward dipping reflection bands between 6 and 14 s TWT could be interpreted as indications for the downgoing plate.
Vargas, C.; De La Hoz, M.; San Martin, V.; Contreras, P.; Navarro, J. M.; Lagos, N. A.; Lardies, M.; Manríquez, P. H.; Torres, R.
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
Souvignet, M.; Heinrich, J.
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
Schneider, Wolfgang; Donoso, David; Garcés-Vargas, José; Escribano, Rubén
Here we present results of direct observations of seawater temperature and salinity over the continental shelf off central-south Chile that shows an unprecedented cooling of the entire water column and an increase in upper layer salinity during 2002 to 2013. We provide evidence that this phenomenon is related to the intensification but mostly to a recent southward displacement of the South Pacific High over the same period, from 2007 on. This in turn has accelerated alongshore, equatorward, subtropical coastal upwelling favorable winds, particularly during winter, injecting colder water from below into the upper water column. Consequently, the environmental conditions on the shelf off central-south Chile shifted from a warmer (fresher) to a cooler (saltier) phase; water column temperature dropped from 11.7 °C (2003-2006) to 11.3 °C (2007-2012) and upper layer salinity rose by 0.25; water column stratification gradually decreased. The biological impacts of such abrupt cooling are apparently already happening in this coastal ecosystem, as recent evidence shows substantial changes in the plankton community and negative trends in zooplankton biomass over the same period.
Hildreth, W.; Grunder, A.L.; Drake, Robert E.
A composite ring-structure caldera of Late Pleistocene age, 26 X 14km in size, has been discovered and mapped near the Andean crest in central Chile (35o 30'S). Rhyolitic to dacitic zoned ashflow sheets, each representing 150-300 km3 of magma, were erupted 0.8, 0.3 and 0.15 m.y. ago; the youngest of the associated collapses was closely followed by resurgent doming of the caldera floor and the development of a longitudinal graben. Post-caldera eruption of dacite and andesite have persisted into Holocene time and active hot springs are abundant along caldera-marginal and resurgent fault systems, suggesting a significant geothermal energy resource. The ash-flow magmatism has been no less important in this segment of the glaciated S Andes than in the arid central Andes and may well be accounted for by the existence of thicker crust in both regions.- L.H.
Woodell, D.; Anderson, M. L.
This study compares the strain experienced by the subducting lithosphere in analog models to the strain recorded by earthquakes in the subduction zone that includes the Juan Fernández Ridge (JFR), near 33 S, 73 W, off the coast of central Chile. The JFR is an aseismic hot spot ridge that has a thickened oceanic crust. The overthickened crust reduces the total density of the slab when compared to the surrounding slab areas, and thus increases the buoyancy of the subducting Nazca plate at this particular location. It is hypothesized that the Nazca plate experiences “flat-slab” subduction at the JFR subduction zone due to this buoyancy. Brudzinski and Chen (2005) argue that, due to the poorly aligned direction of maximum extension (T axes) for earthquakes in the subducting slab in flat-slab subduction zones, the theory of “slab pull” may not be valid for flat-slab subduction zones, and there must be other forces at work. However, Anderson et al. (2007) develop new, more precise slab contours from newly determined earthquake locations and use these contours to qualitatively compare the earthquake data to slab dip directions and thus expected slab-pull directions. They conclude that T axes are parallel to slab dip, and thus slab pull is the only force necessary for explaining the T axis direction. In this study, we quantitatively compare extension produced in analog "flat-slab" models in the laboratory to T axes from the Anderson et al. (2007) study, extending and further testing their idea. Several materials comprise the analog models. Light corn syrup represents the asthenosphere, while silicon putty represents the lithosphere. Recreating the dynamics of the buoyant JFR necessitates two different densities of silly putty: a denser one for the bulk of the slab, and a less dense one for the buoyant ridge. Shallow circular indentations (strain ellipses) on the slab facilitate recording of the strain in the subducting slab. Video and still pictures record each
Vicuna, S.; Alvarez, P.; Melo, O.; Dale, L. L.; Meza, F. J.
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
Muñoz, G; Valdivia, I; López, Z
We describe the life cycle of the bucephalid Prosorhynchoides carvajali from the intertidal rocky zone of central Chile. To elucidate the life cycle of this digenean, two mytilid bivalves, Semimytilus algosus and Perumytilus purpuratus, and ten intertidal fish species belonging to the families Blenniidae, Tripterygiidae, Labrisomidae, Kyphosidae and Gobiesocidae were analysed for natural infections. In addition, experimental infections of fish were undertaken and molecular analyses were performed of several developmental stages of the digeneans in various host species. Experimental infections of fish were made from infected mytilids to determine which fish species were suitable for the metacercarial stage of Prosorhynchoides. We also determined the abundance and prevalence of metacercariae in natural infections in fish and found that they were lower than in the experimental infections. A molecular analysis showed that sporocysts from S. algosus were identical to metacercariae from five fish species and P. carvajali adults. Sporocysts isolated from P. purpuratus were similar to metacercaria found in one fish species only (G. laevifrons) but were different from P. carvajali, with 1.9-2.0% genetic divergence. Therefore, the complete life cycle of P. carvajali consists of the mytilid species S. algosus as the first intermediate host, at least five intertidal fish species as second intermediate hosts (Scartichthys viridis, Auchenionchus microcirrhis, Hypsoblennius sordidus, Helcogrammoides chilensis and Gobiesox marmoratus), two carnivorous fish as definitive hosts (Auchenionchus microcirrhis and A. variolosus) and one occasional definitive host (Syciases sanguineus). This is the second description of a life cycle of a marine digenean from Chile.
Voelker, D.; Stipp, M.
The fixation of water in the oceanic crust and upper mantle, the flux of stored water into subduction zones and the partial liberation of those fluids underneath the forearc and arc are mechanisms that impact on almost every aspect of subduction zone processes, e.g. intensity and type of arc volcanism, deposition of ores and seismicity of the subduction fault, but also on global geochemical budgets by recycling material back into the continental crust. Much of that water fixation happens at the outer rise of subduction zones in particular by deep percolation of fluids to the upper mantle along bend faults. Offshore Chile, the age of the subducting Nazca Plate varies between 0 Ma at the Chile Triple Junction (46°S) and ~38 Ma at the latitude of Valparaíso (32°S). Age-related variations in the thermal state of the subducting Nazca Plate impact on the water influx to the subduction zone, as well as the volumes of water that are released under the continental forearc or, alternatively, carried into the deeper mantle. Southern Central Chile is an ideal setting to study this effect, because other factors important 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 forearc 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 and the release of water vary drastically over a length of 1500 km. 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 forearc 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
Torres, Rodrigo; Ampuero, Patricio
Carbonate system parameters (pH and alkalinity) were used to estimate the coastal water CO 2 fluxes off central Chile (30°S) during September 2007. Coastal waters rich in nitrate and silicate were strongly CO 2 supersaturated and normally poor in chlorophyll a. MODIS satellite chlorophyll a data suggest that phytoplankton biomass remained particularly low during September 2007 although coastal waters were highly fertilized with nitrate and silicate. The phytoplankton gross primary productivity in macronutrient-rich waters was very low with the exception of shallow waters (e.g. within or near bays). Several iron-enrichment bottle experiments show that fCO 2 rapidly decreases during iron-enrichment treatments compared to controls. This suggests that iron limitation of phytoplankton growth (mainly diatoms) plays a role in maintaining high-CO 2 outgassing by preventing rapid interception of upwelled CO 2.
Berger, Erich; Balmert, David; Richter, Jürgen
The project WEIN was funded by the Federal Ministry of Education and Research (BMBF | Berlin, Germany) in the framework of the high-tech strategy of Germany's program "KMU-Innovativ". The project started in 2012 and was completed in 2014. In the scope of the project, an integrated system for analysis, monitoring and information at river basin level was developed, which provides relevant information for all stakeholders that are concerned with water resource issues. The main objective of the project was to improve water use efficiency and hence ensure the agricultural production in the region. The pilot region, in which this system was implemented, is the semi-arid Limarí basin in Northern Central Chile. One of the main parts of the project was the development and implementation of a web- and app-based irrigation water ordering and accounting system for local farmers.
Voelker, D.; Kopf, A.; Ikari, M.; Trütner, S.
Reloca Slide is a submarine failure of ~ 24 km3 volume at the lower slope of the continental margin of Central Chile. The sliding event appears to be of post-Last Glacial Maximum (LGM) age. The evacuation site exhibits a 30° steep and 2000 m high failure plane, the slide deposits in the Chile Trench are preserved as scattered 10-600 m high angular blocks incorporated in a ~60 m high debris fan. The combination of a steep and high failure surface (high velocity) and the apparent cohesiveness of the displaced material (little disintegration) makes Reloca Slide a likely source for a local tsunami. Our numerical simulations show that a comparable event at the lower slope would generate waves of > 8 m offshore amplitude that would impact the Chilean coast within ~25 minutes. Reloca Slide is unique along the Central Chilean margin by its size and particular morphology. Yet, much of the unfailed lower slope along a ~1500 km long stretch shares general morphology, tectonic situation and sedimentary properties with the Reloca Slide source region. It is therefore of high relevance for risk mitigation to understand preconditioning factors and triggering mechanisms of as critical boundary conditions for similar potential future events. Core samples were taken directly from the failure plane, oedometer tests indicate a former burial depth of ~ 500 m. Samples are used to run geotechnical experiments for an improved understanding of the mechanics of the failure process. We are particularly interested in the question of whether the failure of the lowermost slope is a continuing process linked to the subduction of the Nazca Plate (e.g. a process needed to re-establish a critically tapered accretionary wedge), or, alternatively, if it is related to particular local conditions or an exceptional triggering event. We report on results from direct and rotary shear experiments to characterize frictional properties and strength of the materials at the detachment surface of the slide.
Rodil, Iván F.; Jaramillo, Eduardo; Acuña, Emilio; Manzano, Mario; Velasquez, Carlos
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.
Laursen, J.; Normark, W.R.
The Valparaiso Basin constitutes a unique and prominent deep-water forearc basin underlying a 40-km by 60-km mid-slope terrace at 2.5-km water depth on the central Chile margin. Seismic-reflection data, collected as part of the CONDOR investigation, image a 3-3.5-km thick sediment succession that fills a smoothly sagged, margin-parallel, elongated trough at the base of the upper slope. In response to underthrusting of the Juan Ferna??ndez Ridge on the Nazca plate, the basin fill is increasingly deformed in the seaward direction above seaward-vergent outer forearc compressional highs. Syn-depositional growth of a large, margin-parallel monoclinal high in conjunction with sagging of the inner trough of the basin created stratal geometries similar to those observed in forearc basins bordered by large accretionary prisms. Margin-parallel compressional ridges diverted turbidity currents along the basin axis and exerted a direct control on sediment depositional processes. As structural depressions became buried, transverse input from point sources on the adjacent upper slope formed complex fan systems with sediment waves characterising the overbank environment, common on many Pleistocene turbidite systems. Mass failure as a result of local topographic inversion formed a prominent mass-flow deposit, and ultimately resulted in canyon formation and hence a new focused point source feeding the basin. The Valparaiso Basin is presently filled to the spill point of the outer forearc highs, causing headward erosion of incipient canyons into the basin fill and allowing bypass of sediment to the Chile Trench. Age estimates that are constrained by subduction-related syn-depositional deformation of the upper 700-800m of the basin fill suggest that glacio-eustatic sea-level lowstands, in conjunction with accelerated denudation rates, within the past 350 ka may have contributed to the increase in simultaneously active point sources along the upper slope as well as an increased
Yannicelli, Beatriz; Castro, Leonardo; Parada, Carolina; Schneider, Wolfgang; Colas, Francois; Donoso, David
In situ and modeled spatial distribution of squat lobster ( Pleuroncodes monodon) larvae over the continental shelf off south central Chile (35-37°S) was analyzed along with currents and hydrography. We aimed to identify the main larval transport/retention characteristics in the study area, which constitutes the southernmost P. monodon fishing grounds embedded in the Humboldt Current System. We hypothesized that the main contribution to population renewal originates in the two persistent adult aggregations close to the nursery ground that occurs over a continental shelf terrace limited by two submarine canyons. Two extensive bio-physical field campaigns were carried out during the main 2001-2002 upwelling season field data indicated that larvae were released from late austral winter to spring from spots to the north and south of the nursery. Zoea I were found mainly below 50 m depth in southward-flowing waters, whereas older zoea dominated in northward flowing layers above 50 m. Larvae were circumscribed between the coast and the shelf break front and pelagic retention areas were identified over the widest shelf area. Megalopa and juveniles during March, were only found over the nursery area. Individual based simulations coupled to the output of a hydrodynamic model (climatological configuration) for the studied area, showed that the release sites close to the nursery made the largest contribution to recruitment. Sites further north could also contribute to recruitment if hatching occurred later in the upwelling season. The contribution of vertical behavior to larval success was also important, as was the former’s interaction with the site and time of larval release. Our results support the relevance of coastal circulation (affected by topography) on the persistence of P. monodon populations off southern Chile, and the modulation of temporal variability. These results might apply to other abundant species in the area.
Herrera, Hector; Valadares, Rafael; Contreras, Domingo; Bashan, Yoav; Arriagada, Cesar
Little is known about Orchidaceae plants in Chile and their mycorrhizal associations, a key issue for designing protective actions for endangered species. We investigated root fungi from seven terrestrial orchid species to identify potential mycorrhizal fungi. The main characteristics of Rhizoctonia-like fungi were observed under light microscopy, and isolates were identified through PCR-ITS sequencing. Molecular identification of fungal sequences showed a high diversity of fungi colonizing roots. Fungal ability to germinate seeds of different orchids was determined in symbiotic germination tests; 24 fungal groups were isolated, belonging to the genera Tulasnella, Ceratobasidium, and Thanatephorus. Furthermore, dark septate and other endophytic fungi were identified. The high number of Rhizoctonia-like fungi obtained from adult orchids from the Coastal mountain range suggests that, after germination, these orchids may complement their nutritional demands through mycoheterotrophy. Nonetheless, beneficial associations with other endophytic fungi may also co-exist. In this study, isolated mycorrhizal fungi had the ability to induce seed germination at different efficiencies and with low specificity. Germin ation rates were low, but protocorms continued to develop for 60 days. A Tulasnella sp. isolated from Chloraea gavilu was most effective to induce seed germination of different species. The dark septate endophytic (DSE) fungi did not show any effect on seed development; however, their widespread occurrence in some orchids suggests a putative role in plant establishment.
Hervé Fernández, Pedro; Oyarzún, Carlos; Huyghens, Dries; Verhoest, Niko; Boeckx, Pascal
Recent studies using water stable isotopes (δ2H and δ18O) have described an ecohydrological separation of water between streams and trees indicated as the "two water world hypothesis". In this study, we monitored water compartments at two catchments near Valdivia (Chile) covered by old growth native evergreen forest (NF) and a Eucalyptus nitens stand covered catchment (or EP), throughout approximately 1.5 years. Our results showed that precipitation, stream and suction lysimeter water plots approximately along the δ2H/δ18O slope of local precipitation inputs (LMWL). However, bulk soil and xylem water plots below the LMWL, supporting the "two water worlds hypothesis". This suggests that trees are using water that is not contributing to stream water. However, we also found evidence of connectivity between the two water worlds, potentially caused by heavy rainfall events, for a brief period (autumn and winter) especially in EP. Our results also suggests that precipitation falling during autumn-winter period is the main water supply for streamflow and bulk soil water, which share a similar precipitation source as Aetoxicon punctatum (in NF) and 4 years old Eucalyptus nitens stand (in EP). We conclude that the "two water worlds hypothesis" applies under certain environmental conditions.
Gutiérrez, Marcelo H; Jara, Ana M; Pantoja, Silvio
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.
Alam, M.; Muñoz, M.; Parada, M.
Geothermal system associated with the Pleistocene-Holocene Sierra Nevada volcano (SNVGS) in the Araucanía Region of Chile has surface manifestations from the north-western flank of the volcano, up to Manzanar and Malalcahuello. Baños del Toro, located on the northwestern flank of the volcano, has numerous fumaroles and acid pools (acid sulfate waters, T=~90°C, pH=2.1, TDS=3080 mg/L); while Aguas de la Vaca, near the base of the volcano, has a bubbling spring (chloride-sulfate waters, T=~60°C, pH=7.0, TDS=950 mg/L). Five shallow (<120m) wells (2 at Manzanar and 3 at Malalcahuello) dug and drilled in the Cautín River Valley discharge alkaline (pH= 9-10) waters with relatively low TDS (130-210mg/L). The main heat source of the geothermal system is apparently the magmatic system of the Sierra Nevada volcano. Liquiñe-Ofqui Fault Zone (LOFZ) that transects the area forms excellent conduits for the flow of the geothermal waters. The geothermal reservoirs are hosted in the volcanic rocks interceded with glacial deposits over the North Patagonian Batholith that forms an impermeable barrier, and thus constitutes the lower boundary of the geothermal system and also controls the lateral flow of the fluids. An equilibrium temperature of ~210°C is derived from gas geothermometry (CO2/Ar-H2/Ar) of the discharges at Baños del Toro. Geothermal fluids from the upflow area on the northwestern flank of the volcano migrate northwards to the Cautín River Valley. The geothermal system has a high enthalpy reservoir(s) on the northwestern flank of the Sierra Nevada volcano and low-enthalpy reservoirs in the Cautín River Valley that have been tapped to form spas at Manzanar and Malalcahuello. While sub-vertical fractures of LOFZ facilitate the recharge of the system, lateral flow of the geothermal fluids is apparently controlled by lithology; Melipueclo Pluton in particular prevents the westward flow from the upflow zone, causing the flow only northwards to Malalcahuello and
Mason, Meghan R.; Encina, Carolina; Sreevatsan, Srinand; Muñoz-Zanzi, Claudia
Background Leptospirosis is a neglected zoonosis affecting animals and humans caused by infection with Leptospira. The bacteria can survive outside of hosts for long periods of time in soil and water. While identification of Leptospira species from human cases and animal reservoirs are increasingly reported, little is known about the diversity of pathogenic Leptospira species in the environment and how surveillance of the environment might be used for monitoring and controlling disease. Methods and Findings Water samples (n = 104) were collected from the peri-domestic environment of 422 households from farms, rural villages, and urban slums participating in a broader study on the eco-epidemiology of leptospirosis in the Los Rios Region, Chile, between October 2010 and April 2012. The secY region of samples, previously detected as pathogenic Leptospira by PCR, was amplified and sequenced. Sequences were aligned using ClustalW in MEGA, and a minimum spanning tree was created in PHYLOViZ using the goeBURST algorithm to assess sequence similarity. Sequences from four clinical isolates, 17 rodents, and 20 reference strains were also included in the analysis. Overall, water samples contained L. interrogans, L. kirschneri, and L. weilii, with descending frequency. All species were found in each community type. The distribution of the species differed by the season in which the water samples were obtained. There was no evidence that community-level prevalence of Leptospira in dogs, rodents, or livestock influenced pathogen diversity in the water samples. Conclusions This study reports the presence of pathogenic Leptospira in the peri-domestic environment of households in three community types and the differences in Leptospira diversity at the community level. Systematic environmental surveillance of Leptospira can be used for detecting changes in pathogen diversity and to identify and monitor contaminated areas where an increased risk of human infection exists. PMID
Kempf, P.; Moernaut, J.; Vandoorne, W.; Van Daele, M. E.; Pino, M.; Urrutia, R.; De Batist, M. A. O.
After the last decade of extreme tsunami events with catastrophic damage to infrastructure and a horrendous amount of casualties, it is clear that more and better paleotsunami records are needed to improve our understanding of the recurrence intervals and intensities of large-scale tsunamis. Coastal lakes (e.g. Bradley Lake, Cascadia; Kelsey et al., 2005) have the potential to contain long and continuous sedimentary records, which is an important asset in view of the centennial- to millennial-scale recurrence times of great tsunami-triggering earthquakes. Lake Huelde on Chiloé Island (42.5°S), Chile, is a coastal lake located in the middle of the Valdivia segment, which is known for having produced the strongest ever instrumentally recorded earthquake in 1960 AD (MW: 9.5), and other large earthquakes prior to that: i.e. 1837 AD, 1737 AD (no report of a tsunami) and 1575 AD (Lomnitz, 1970, 2004, Cisternas et al., 2005). We present a new 5400 yr-long paleotsunami record with a Bayesian age-depth model based on 23 radiocarbon dates that exceeds all previous paleotsunami records from the Valdivia segment, both in terms of length and of continuity. 18 events are described and a semi-quantitative measure of the event intensity at the study area is given, revealing at least two predecessors of the 1960 AD event in the mid to late Holocene that are equal in intensity. The resulting implications from the age-depth model and from the semi-quantitative intensity reconstruction are discussed in this contribution.
FaríAs, Marcelo; Charrier, Reynaldo; Carretier, SéBastien; Martinod, Joseph; Fock, AndréS.; Campbell, David; CáCeres, JoaquíN.; Comte, Diana
We address the question of the late Cenozoic geomorphological evolution of the central Chile Andes (33°-35°S), using uplift markers, river incision, previous and new ages of volcanic bodies, and new fission track ages. The uplift markers consist of relicts of high elevated peneplains that evidence >2 km of regional surface uplift lasting ˜2 Ma with variable amount along an E-W transect. The eastern Coastal Cordillera was uplifted 1.5-2.1 km at 33-34°S and <1 km at 35°S, the western Principal Cordillera was uplifted ˜2 km, and the central eastern Principal Cordillera was uplifted >2.5 at 33°45'S and ˜1.5 km at 34°30'S. Erosional response to uplift was characterized by the retreat of a sharp knickpoint with celerities between 10 and 40 mm a-1. Extrapolation using a stream power law shows that uplift began shortly before 4 Ma or at 10.5-4.6 Ma (7.6 Ma central age) depending on the morphostructural units involved. The first alternative implies simultaneous uplift of the continental margin. The second model (the most reliable one) implies that the uplift affected together the eastern Coastal Cordillera and the Principal Cordillera, while the rest of the western fore arc subsided. This regional uplift can be mostly balanced by crustal thickening resulting from coeval shortening related to the out-of-sequence thrusting event in the Principal Cordillera and the uplift of the Frontal Cordillera. Simultaneously, emplacement of the southern edge of the flat slab subduction zone might have partially contributed to this uplift event.
Rabbia, Osvaldo M.; Correa, Karen J.; Hernández, Laura B.; Ulrich, Thomas
The El Abra porphyry copper deposit belongs to the Late Eocene—Early Oligocene metallogenic belt of northern Chile, which host several world-class porphyry copper deposits. Our previous geochronological work done on this deposit provides the temporal framework for petrological data interpretation. The magmatic history of the El Abra deposit lasts for 8.6 Ma and can be divided into two stages. An early period, from about 45 to 38.7 Ma, dominated by diorites and quartz monzodiorites with "normal" (non-adakite) arc geochemistry and a late period, with rocks younger than 38.7 Ma that developed adakite-like geochemistry, where equigranular granodiorites are the volumetrically dominant rock type (e.g., Clara granodiorite 38 Ma). These granodiorites are then intruded by leucocratic porphyry dikes and aplites. Most copper mineralization is associated with multiple intrusions of these younger porphyritic rocks, described as the El Abra porphyry unit, and emplaced over a 1.4 Ma period, from 37.5 to 36.1 Ma. The adakite-like geochemistry of the younger rock units (<38.7 Ma) is attested by a significant depletion in REE contents, particularly MREE and HREE (concave MREE distribution patterns), high La/Yb and Sr/Y ratios, and Na2O and Al2O3 contents, along with the absence of the Eu anomaly in normalized REE distribution patterns. The evolution of this large, long-lived magmatic system from "normal" to adakite-like arc magmatism is discussed in a tectonic context of crust overthickening due to a major orogenic episode (Incaic compressive phase). This tectonic setting may have promoted higher pressure conditions at the lower crust "hot zone" and increased the crustal residence time of derivative melts favoring extensive differentiation leading to water-rich (and oxidized?) felsic melts, where amphibole fractionation played an important role. Strontium, Nd, and Pb isotope data suggest a common mantle source for both the non-adakite and adakite-like rocks. This implies that
Cooman, K; Debels, P; Gajardo, M; Urrutia, R; Barra, R
Because of the importance of surface waters from the Chillán River watershed (Chile) for recreation, agricultural irrigation, and the production of drinking water, local concern about river water quality has increased considerably during the last decade. Agricultural and forestry activities in the watershed, characterized by an intensive use of pesticides, are thought to play an important role in the generation of non-point-source pollution, whereas the discharge of urban wastewater from the city of Chillán constitutes a major point source of pollution. In the present investigation, acute and chronic laboratory bioassays using Daphnia spp. were conducted on surface water samples from 17 river stations located throughout the watershed. Sampling occurred on 6 occasions during a 16-month period (2000 to 2001) and included both high and low flow conditions. Almost all toxic effects observed in summer were directly related to the discharge of urban wastewater, whereas toxicity in rural areas was mainly detected during the winter period when rainfall and river flow are high. Toxicity test results were compared with measured physicochemical water-quality data. Mortality and alterations in reproductive success of Daphnia spp. were not consistently reflected in detected chemical pollution. With only one exception (atrazine), detected pesticide concentrations were below known toxicity levels. However, additive and synergistic effects of the presence of a mixture of pesticides could not be excluded as a possible cause of observed toxicity. At several stations, filtering of the water sample led to a strong decrease in toxicity, which suggests the presence of xenobiotics attached to the smaller sediment fraction. Inclusion of sediment chemical analysis and sediment toxicity testing in future work should therefore be encouraged. The presented approach provided information about the adverse effects of human activities on surface water quality in the watershed, not easily
Le Roux, J. P.; Olivares, Danisa M.; Nielsen, Sven N.; Smith, Norman D.; Middleton, Heather; Fenner, Juliane; Ishman, Scott E.
The north-facing Bay of Tongoy in central Chile is flanked by topographic highs in the west and east. During the Miocene and Pliocene, the bay extended inland at least 30 km farther south than a present. It was filled with muds, sands, coquinas and gravel during a series of transgressions and regressions related to regional and local tectonic movements combined with global sea-level variations. 87Sr/ 86Sr and microfossil dating indicates transgressions between 11.9-11.2 Ma, 10.1-9.5 Ma, 9.0-7.3 Ma, 6.3-5.3 Ma, 4.3-2.2 Ma and 1.7-1.4 Ma. The regional tectonic behaviour of the crust shows general uplifting from 10.5 Ma to 6.9 Ma, associated with subduction of the Juan Fernández Ridge (JFR) beneath this part of the continent. Subsidence followed between 6.9 and 2.1 Ma, in the wake of the southeastward-migrating JFR. The subsequent subduction of an oceanic plateau similar to the JFR caused rapid uplift that led to the final emergence of the bay above sea level. The Puerto Aldea normal fault along the western limit of the study area was reactivated during the regional uplift and subsidence events, with reverse faulting occurring during the latter phase. Sporadic fault reactivation probably triggered the rapid changes in water depth reflected in the recorded vertical succession of facies.
Salamanca, Marco; Chandía, Cristian; Hernández, Aldo
The relationship between the occurrence of forest fires in central Chile and the total concentration of dioxins and furans (PCDD/F) in nearby coastal waters was analyzed. The data for this analysis was obtained from a long-term environmental monitoring program (PROMNA) in the Bio-Bio Region. Quantification of PCDD/F was performed using HRGC/HRMS at the MSS laboratory in England. Between 2006 and 2014, peaks were observed in February 2007 and 2012. These concentration maxima coincided with major forest fires in the Bio-Bio Region and particularly with those in the Itata River Basin. The January 2012 fires generated an intense short-term response that was associated with atmospheric transport which increases medium toxicity furan-type congeners concentrations (TCDF, PCDF and HxCDF) and six months later a concentration increase of low toxicity dioxin-type congeners was observed (OCDD, HpCDD and HxCDD) coinciding with maximum winter river flow. These results suggest that forest fires near the coastal zone are responsible for increases in PCDD/F concentration observed in the study area.
Aravena, Guillermo; Broitman, Bernardo; Stenseth, Nils Christian
We use time-series analyses to characterize the effects of recent climate variability upon the local physical conditions at 11 study sites along the northern-central coast of Chile (29–34°S). Environmental indices show that the 1° Bakun upwelling index in this coastal region has fluctuated in time, starting from a stable period around the 1980's, peaking during the mid 90s, decreasing during the next ten years and increasing at a steep rate since 2010. Upwelling intensity decreased with increasing latitude, showing also a negative correlation with climate patterns (El Niño3 sea surface temperature-SST anomalies and the Multivariate El Niño Index). We hypothesize that the impacts of climate variability on upwelling events seem to be spatially heterogeneous along the region. Non-sheltered locations and, particularly, sites on prominent headlands show an immediate (lag = 0) and negative correlation between local SST, upwelling events and wind stress. We suggest that near-shore thermal conditions are closely coupled to large-scale forcing of upwelling variability and that this influence is modulated through local topographic factors. PMID:24587310
Aravena, Guillermo; Broitman, Bernardo; Stenseth, Nils Christian
We use time-series analyses to characterize the effects of recent climate variability upon the local physical conditions at 11 study sites along the northern-central coast of Chile (29-34°S). Environmental indices show that the 1° Bakun upwelling index in this coastal region has fluctuated in time, starting from a stable period around the 1980's, peaking during the mid 90s, decreasing during the next ten years and increasing at a steep rate since 2010. Upwelling intensity decreased with increasing latitude, showing also a negative correlation with climate patterns (El Niño3 sea surface temperature-SST anomalies and the Multivariate El Niño Index). We hypothesize that the impacts of climate variability on upwelling events seem to be spatially heterogeneous along the region. Non-sheltered locations and, particularly, sites on prominent headlands show an immediate (lag = 0) and negative correlation between local SST, upwelling events and wind stress. We suggest that near-shore thermal conditions are closely coupled to large-scale forcing of upwelling variability and that this influence is modulated through local topographic factors.
Martínez, Fernando; Bonini, Marco; Montanari, Domenico; Corti, Giacomo
We present the results of a series of analog models addressing the relationships between tectonic inversion and magmatism, taking the Lautaro Basin in northern Chile (27-28° S), Central Andes as a natural case. The experiments consisted of extension and orthogonal shortening of sand-silicone models to reproduce the tectonic inversion of a previous extensional system synchronous with the emplacement of analog magma. We analyzed how the variation in the rate of magma intrusion, shortening, and syn-compressive sedimentation may affect the final configuration of an inverted system, and the results were compared with field observations. Our results showed that (i) folding of syn-rift deposits and increased steepness of the master faults accommodate the shortening of the extensional system, (ii) magmatic intrusions condition the final geometries (top view and cross-section) of inverted normal faults in the models and in the Lautaro Basin, (iii) magma tends to migrate preferentially along the inverted faults, and accumulates beneath the faults and in the core of the inversion anticlines, (iv) the syn-inversion magmatism may indicate the migration pathways, which favor major lubrication and slip on the structures during their reactivation.
Aldana, Marcela; Pulgar, José M; Orellana, Nathalie; Patricio Ojeda, F; García-Huidobro, M Roberto
The rapid increase in body size and abundance of most species inside Management and Exploitations Areas for Benthic Resources (MEABRs) has led to the proposal of these areas as a good complement for achieving the conservation objectives of Marine Protected Areas (MPAs). However, when evaluating MEABRs and MPAs as conservation and/or management tools, their impact upon parasite populations has rarely been considered, despite the fact that epidemiological theory suggests an increased susceptibility to parasitism under high population abundance. We evaluated the effects of MEABRs on the parasite abundance of Proctoeces lintoni and its impact on the growth of the host limpet Fissurella crassa in central Chile. Parasitic magnitude was higher inside MEABRs than in Open-Access Areas, and parasitized limpets showed a greater shell length, muscular foot biomass, and gonadosomatic index compared to non-parasitized limpets of the same age. Our results suggest that the life cycle of P. lintoni and, consequently, its trophic links have been strengthened inside MEABRs. The increased growth rate could reduce the time required to reach the minimum catch size and increase the reproductive and muscular output of the host population. Thus, parasitism should be considered in the conservation and management of economically important mollusk hosts.
Haas, J.; Olivares, M. A.; Palma, R.
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
Arancibia, G.; Daniele, L.; Navarro, L.; Astudillo, F.; Vázquez, M.; Morata, D.
The interaction between fault zones and hydrogeological domains are an open challenge and require the understanding of the complex relationship between structure, fluid flow and hydrothermal transport and processes. Faults stimulate hydraulic conductivity when acting as conduit, but it can also be a barrier by mineral precipitation and comminution. Structural heterogeneity of fractured lithology induces a flow partition within the aquifer system creating preferential flows paths and some fracture connectivity. We propose an interdisciplinary approach from hydrogeological and structural point of view, in a low-enthalpy aquifer system in the central valley of Central Chile, where several low-temperature thermal springs are spatially related to regional long-lived fault zone (Pocuro Fault Zone). Pocuro Fault zone is a kilometric NS-striking steeply dipping fault zone, with at least 50 km long. Metric wide fault core includes gouge and cataclastic rocks, whereas decametric damage zone consists of intensely fractured and hydrothermal altered Meso-Cenozoic volcanic and volcaniclastic host rocks, crossed by centimetric to milimetric subvertical NE-striking veins. Preliminary results of vein infill clays minerals and zeolites from damage zone, suggest P-T conditions interpreted as an exhumed fossil high-temperature (120º-230ºC) geothermal system. Currently, only low-temperature thermal springs are discharging with different geochemical patterns (bicarbonate to chlorine and sulphate dominant ions) and a homogeneous temperature range (20º-25ºC). This is an interesting study case, to better understand the permeability evolution of geothermal system and the link between internal fault architecture, hydrogeology and hydrothermal inputs.
Lange, Dietrich; Geersen, Jacob; Barrientos, Sergio; Moreno, Marcos; Grevemeyer, Ingo; Contreras-Reyes, Eduardo; Kopp, Heidrun
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.
Castro, Leonardo R.; Troncoso, Victor A.; Figueroa, Dante R.
In order to understand the mechanism by which zooplankters from different origins co-occur during the upwelling season within Golfo de Arauco, one of the most productive areas in central Chile, we assessed short term variations in the vertical distribution of the most abundant copepod species. Fine-scale, day and night vertical zooplankton sampling was done with a pump over 12 days in summer. The water column in the gulf consisted of three layers: Equatorial Subsurface Water of low dissolved oxygen content in the deeper part of the water column, strong temperature and oxygen gradients at mid-depth (15-25 m), and a layer of warmer, more oxygenated, less saline water at the surface. Copepods within the gulf originated from offshore, from the continental shelf, and from the coastal area. Most taxa showed distinctive vertical distributions. Three copepod groups were identified by their mean weighted depths of residence. One group included shallow residents found above the thermocline/oxycline ( Acartia tonsa, Centropages brachiatus, Corycaeus sp., Paracalanus parvus, Oncaea sp.). A second group was comprised by species distributed at or below the thermocline/oxycline ( Oithona sp., Oncaea conifera, Lucicutia sp., Metridia sp., Heterorhabdus papilliger). The third group was composed of vertical migrators that crossed the thermocline/oxycline ( Calanus chilensis, Calanoides patagoniensis, Aetideus armatus, Pleuromamma piseki). In spite of their different vertical distribution ranges, the most abundant and frequent copepod species ( P. parvus, C. chilensis, C. patagoniensis, C. brachiatus) share a common capacity to withstand wide ranges of oxygen concentration and temperature. This characteristic, along with the capacity to vary their life strategies under different environmental conditions, seems to facilitate the maintenance of large numbers of copepods in coastal waters along the Humboldt Current.
Burgener, L. K.; Huntington, K. W.; Hoke, G. D.; Schauer, A. J.; Ringham, M. C.; Latorre Hidalgo, C.; Díaz, F.
The application of carbonate clumped isotope thermometry to soil carbonates has the potential to shed new light on questions regarding terrestrial paleoclimate. In order to better utilize this paleoclimate tool, outstanding questions regarding seasonal biases in soil carbonate formation and the relationship between soil carbonate formation temperatures (T(Δ47)) and surface temperatures must be resolved. We address these questions by comparing C, O, and clumped isotope data from Holocene/modern soil carbonates to modern meteorological data. The data were collected along a 170 km transect with >4 km of relief in central Chile (~30°S). Previous studies have suggested that soil carbonates should record a warm season bias and form in isotopic equilibrium with soil water and soil CO2. We identify two discrete climate zones separated by the local winter snow line (~3200 m). Below this boundary, precipitation falls as rain and soil carbonate T(Δ47) values at depths >40 cm resemble summer soil temperatures; at higher elevations, precipitation falls as snow and T(Δ47) values resemble mean annual soil temperatures. Soil carbonates from the highest sample site (4700 m), which is devoid of vegetation and located near perennial snow fields, yield anomalous δ18O, δ13C, and T(Δ47) values, indicative of kinetic isotope effects that we attribute to cryogenic carbonate formation. Our results suggest that soil carbonates from depths <40 cm are affected by large, high frequency variations in temperature and precipitation, and should not be used as paleotemperature proxies. These findings (1) highlight the role of soil moisture in modulating soil carbonate formation and the resulting T(Δ47) values, (2) underscore the importance of understanding past soil moisture conditions when attempting to reconstruct paleotemperatures using carbonate clumped isotope thermometry, and (3) suggest that soil carbonates from high elevation or high latitude sites may form under non
Fleury, Marina; Marcelo, Wara; Vásquez, Rodrigo A.; González, Luis Alberto; Bustamante, Ramiro O.
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
Gilbert, D. J.; Freundt, A.; Kutterolf, S.; Hansteen, T. H.; Amigo, A.; Burkert, C.
On June 4th 2011 the Puyehue-Cordon Caulle volcanic complex (PCCVC, 40.590°S, 72.117°W) in South Central Chile woke after 51 years of dormancy. The rhyodacitic eruption produced an ash plume that reached altitudes of 10.7-12.2 km causing severe problems for civil aviation in the southern hemisphere. The PCCVC is part of the Southern Volcanic Zone of the Andes, that formed in response to the oblique subduction of the Nazca Plate beneath the South American Plate. We investigated juvenile components of the June 2011 eruption that were sampled within the very first three days of the eruption from proximal and distal locations. Bulk rock, matrix glass, mineral, and melt inclusion analyses were performed. Matrix glasses show relatively homogeneous major element compositions (e.g. SiO2 ranging from 70 to 71 wt%) indicating a compositionally homogeneous pre-eruptive magma chamber. The mineral paragenesis comprises plagioclase, clinopyroxene, orthopyroxene, Fe-Ti-oxides, and apatite. Mineral and glass data were used to compute pre-eruptive P-T-conditions based on several independent thermobarometers. Cpx-liq-thermobarometry reveals crystallization pressures from 50 to 250 MPa suggesting a shallow magma chamber at depths of 2 to 9 km and magma temperatures of 875 to 900°C. Volatile data and the occurrence of water-dominated magmatic fluid inclusions indicate the exsolution of a sulphur-rich fluid phase occurring at an early stage during differentiation. H2O contents of 4-6 wt% suggest that the erupted melt had become water-saturated at reservoir depth such that the June, 2011 eruption was probably triggered by gas overpressure. Comparison with data from older tephras recorded in the tephrostratigraphy of the PCCVC (Lara et al., 2006) show that relatively shallow reservoirs and pre-eruptive H2O saturation appear to be typical features of explosive eruptive events at this volcanic system.
Ibáñez, Christian M.; Arancibia, Hugo; Cubillos, Luis A.
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.
Ruiz, A. C.; MacInnes, B. T.; Ely, L. L.; Cisternas, M. A.; Gelfenbaum, G. R.; Richmond, B. M.; Meneses, D. J.
The February 27, 2010 Mw 8.8 Maule earthquake and tsunami that struck south-central Chile altered the coastal landscape, leaving a depositional record at many locations along the coast. Our research is questioning whether tsunami deposits originally described during post-tsunami surveys in La Trinchera, Constitución and Coliumo soon after the event change significantly over time. The deposits initially described in 2010 were revisited 5 years later to determine if taphonomic changes occurred and to assess the long-term preservation potential of deposits with different initial characteristics and settings. We recently made measurements of deposit thickness, grain size, grading, sedimentary structures, incipient soil development and accumulation of organic material. Results indicate that deposit thickness and the maximum inland extent of recognizable deposits had decreased slightly since 2010, while overlying soil development and accumulation of organic matter increased. Few deposits had been altered by bioturbation. We will use the inland extent of the deposits surveyed in 2015 to model a minimum size of the 2010 earthquake and tsunami in GeoClaw. The results will be compared with independent geophysical models of the rupture characteristics. This can be used as a case study that can be applied to earlier paleo-earthquake and tsunami events in which seismic data is sparse or non-existent and the most reliable record is the inundation distance as determined by tsunami deposits. Studying the change of deposits in the geologic record over time can provide key insights into how tsunami deposits are preserved, which is important when working with paleo-deposits that may have been altered since deposition.
Saldías, Gonzalo S.; Largier, John L.; Mendes, Renato; Pérez-Santos, Iván; Vargas, Cristian A.; Sobarzo, Marcus
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.
Fleury, Marina; Marcelo, Wara; Vásquez, Rodrigo A; González, Luis Alberto; Bustamante, Ramiro O
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.
Flynn, John J.; Charrier, Reynaldo; Croft, Darin A.; Gans, Phillip B.; Herriott, Trystan M.; Wertheim, Jill A.; Wyss, André R.
Recent work in the central Andean Main Range of Chile near Laguna del Laja (˜37.5°S, 71°W) has produced the first mammal fossils for the region. Fossils, locally abundant and well preserved, occur patchily across a wide area southeast of the lake. Mammalian remains are derived from generally strongly folded (kilometer-scale) exposures of the locally ˜1.8 km thick, early to middle Miocene Cura-Mallín Formation; two identifiable specimens have been recovered from the overlying Trapa Trapa Formation as well. Both formations consist primarily of well-stratified (1-5 m thick layers) volcaniclastic and volcanic strata, deposited predominantly in fluviatile systems. The Cura-Mallín Formation is possibly the southern continuation of (or lateral equivalent to) the richly fossiliferous Abanico Formation mapped between ˜32°S and 36°S. Intensive sampling in a series of localities east and south of Laguna del Laja has yielded diverse faunas, in addition to radioisotopically dateable horizons. The new fossil mammal faunas represent as many as six South American Land Mammal "Ages" (SALMAs). Fossils, together with preliminary 40Ar/ 39Ar radioisotopic dates, ranging from ˜9 to 20 Ma across the exposed thickness of the Cura-Mallín Formation and into the overlying Trapa Trapa Formation, provide a robust geochronological framework for middle Cenozoic strata in the Laguna del Laja region. The sequence of directly superposed mammalian assemblages at Laguna del Laja is one of the longest in all of South America, rivaled only by the classic Gran Barranca section of Patagonian Argentina. These data illuminate the geological history of the area and its record of mammalian evolution. The potential to isotopically date these diverse faunas with high precision (error ± 0.5 Ma) presents a rare opportunity to calibrate related portions of the SALMA sequence.
Vázquez, M.; Nieto, F.; Morata, D.; Droguett, B.; Carrillo-Rosua, F. J.; Morales, S.
HRTEM textural evidence shows that clay minerals in the Tinguiririca geothermal field (Andean Cordillera, central Chile) are the result of direct alteration of former volcanic glass and minerals by hydrothermal fluids at similar temperatures to the present day. They show the classical pattern of diagenetic transformation from smectite at the top to illite at the bottom, with the progressive formation of corrensite and chlorite. The high fluid/rock ratio, disposability of necessary cations and absence of previous detrital phyllosilicates allow the consideration of this area as a natural laboratory to establish the extreme ideal conditions for very low-T reactions. Transformations from smectite to R1 illite-smectite (I-S) and from these to R3 mixed-layers occur respectively at 80-120 °C and 125-180 °C. In spite of ideal genetic conditions, the new-formed minerals show all the defective character and lack of textural and chemical equilibrium previously described in the literature for diagenetic and hydrothermal low-temperature assemblages. Chemistry of smectite-illite phases evolves basically through a diminution of the pyrophyllitic component toward a theoretical muscovite (Si4 + + □ -> Al3 ++ K+). However, a second chemical vector (Si4 ++ Mg2 + → Al3 ++ Al3 +), that is, decreasing of the tschermack component, also contributes to the evolution toward the less Si-more Al rich muscovite in relation to the original smectite. Residual Mg (and Fe) from the latter reaction is consumed in the genesis of chloritic phases. Nevertheless, as a consequence of the lack of chemical equilibrium (probably because of the short time-scale of the geothermal alteration processes), the composition of clay minerals is highly heterogeneous at the level of a single sample. Consequently, the respective fields of smectite, R1 I-S and R3 I-S overlap each other, making the distinction among these three phases impossible based exclusively on chemical data.
Lamb, S. H.
The Cenozoic geological evolution of the Central Andes, along two transects between ~17.5°S and 21°S, is compared with paleo-topography, determined from published paleo-altimetry studies. Surface and rock uplift are quantified using simple 2-D models of crustal shortening and thickening, together with estimates of sedimentation, erosion and magmatic addition. Prior to ~25 Ma, during a phase of amagmatic flat-slab subduction, thick skinned crustal shortening and thickening was focused in the Eastern and Western Cordilleras, separated by a broad basin up to 300 km wide and close to sea level, which today comprises the high Altiplano. Surface topography in the Eastern Cordillera appears to be ~1 km lower than anticipated from crustal thickening, which may be due to the pull-down effect of the subducted slab, coupled to the overlying lithosphere by a cold mantle wedge. Oligocene steepening of the subducted slab is indicated by the initiation of the volcanic arc at ~27 - 25 Ma, and widespread mafic volcanism in the Altiplano between 25 and 20 Ma. This may have resulted in detachment of mantle lithosphere and possibly dense lower crust, triggering 1 - 1.5 km of rapid uplift (over << 5 Myrs) of the Altiplano and western margin of the Eastern Cordillera and establishing the present day lithospheric structure beneath the high Andes. Since ~25 Ma, surface uplift has been the direct result of crustal shortening and thickening, locally modified by the effects of erosion, sedimentation and magmatic addition from the mantle. The rate of crustal shortening and thickening varies with location and time, with two episodes of rapid shortening in the Altiplano, lasting < 5 Myrs, that are superimposed on a long term history of ductile shortening in the lower crust, driven by underthrusting of the Brazilian Shield on the eastern margin.
Schulze, A.; Micksch, U.; Krawczyk, C. M.; Ryberg, T.; Stiller, M.
The multi-disciplinary project TIPTEQ (from The Incoming Plate to mega-Thrust EarthQuake processes) investigates the seismogenic coupling zone in Southern Central Chile and the associated subduction zone processes between the Pacific Ocean and the volcanic arc. The reflection seismic component of TIPTEQ includes a 110 km long profile which spans from the coast over the down-dip end of the seismogenic coupling zone, crossing the 1960 Valdivia earthquake hypocentre. 180 three-component geophones were deployed (100 m spacing) along an 18 km wide spread whereof 4.5 km were shifted in a daily roll-along. With 100 borehole shots, 1.5 km apart, this up to 8-fold covered line delivers a high-resolution image of the seismogenic coupling zone. 15 additional shots in an expanding spread profiling configuration focussed on the seismogenic coupling zone. SH wave source signals were generated to yield an improved picture of the petrophysical contrasts within the system. The SPOC-South wide-angle data velocity model is combined with a first-break tomography velocity model to get an advanced migration image. The subducting Nazca plate can be traced from a depth of 25 km below the coast down to a depth of 50 km at the eastern end of the profile. Structural evidence suggests that material is transported down in a subduction channel. From slow uplift of the Coastal Cordillera we conclude that basal accretion of parts of this material controls the seismic architecture and growth of the south Chilean crust. Between depths of 5 to 25 km several bright reflectivity spots can be seen in the upper plate, which may suggest fluid traps in the accretionary wedge. The tomographic p-wave velocity model reaches approximately 10 km depth. Its segmentation corresponds to the geological units mapped at surface. The sediment thickness in the Central Valley is approx. 3 km, and we see prominent fault systems like the Lanalhue fault zone also in the tomographic model. At present, almost no seismicity
Rodríguez, María Pía; Carretier, Sébastien; Charrier, Reynaldo; Saillard, Marianne; Regard, Vincent; Hérail, Gérard; Hall, Sarah; Farber, Dan; Audin, Laurence
In north-central Chile, a wide shore platform is morphologically connected with a high fluvial terrace and a pediment. The eastward extension of Quaternary coastal uplift in the Southern Central Andes is poorly constrained since no age correlation between marine and continental landforms has been reported. We use 26Al and 10Be concentrations to constrain the geomorphic evolution of these marine and continental landforms near the Choapa valley (31.6° S). 10Be ages for the shore platform indicate that this surface was repeatedly reoccupied during sea-level highstands between ~ 800 and 500 ka and uplifted after 500 ka. While 'zero erosion' ages for the pediment between ~ 600 and 300 ka only partly overlap the shore platform age range, more realistic exposure ages calculated for an erosion rate of 1 m/Ma are between ~ 945 and 475 ka, fitting the age range of the correlated shore platform. 10Be concentrations of the high fluvial terrace are highly scattered evidencing vertical mixing of clasts probably due to slow lowering of the surface. Although it is not possible to determine an age for this landform, the scattering among its 10Be concentrations implies that this marker is several hundreds of thousands of years old and that the high fluvial terrace began to form at ~ 1200 ka or after. Finally, 10Be concentrations of the high fluvial terrace, the pediment and the shore platform are of the same order of magnitude, which is consistent with the clear morphologic correlation between these three types of landforms. These data suggest that the marine and continental landforms studied formed synchronously, with some local differences, during a long period of relative tectonic stability between ~(1200?) 800 and 500 ka and uplifted after 500 ka. Our results confirm recent studies showing a post-400 ± 100 ka renewal of uplift along the Pacific coast after a Lower to Middle Pleistocene period of slow uplift. Moreover, the extension of the surfaces suggests that a broad region
Hillemann, Christian; Melnick, Daniel; Jara-Muñoz, Julius; Strecker, Manfred R.
Great subduction earthquakes are commonly accompanied by motion of upper-plate faults, either during the megathrust event or in the weeks to months that follow. One of the best documented examples of such coupled behavior is probably the 2010 Pichilemu earthquake sequence of central Chile with MW 6.9 and 7.0 events sourced by a shallow normal fault 11 days after the MW 8.8 Maule earthquake that originated offshore Chile. Similarly, normal faults ruptured the surface after the 2011 Tohoku earthquake in Japan, and additional examples may exist in other subduction environments. Static stress transfer on optimally oriented faults located at the periphery of high-slip sectors has been suggested as the trigger mechanism for these earthquakes following major plate-boundary earthquakes. Numerous normal and reverse faults have been mapped along the ~500-km-long rupture zone of the 2010 Maule earthquake, but post-seismic upper-plate seismicity was concentrated only at the Pichilemu normal fault, which is immediately to the north of the area where slip reached its maximum of 17 m. To gain insight into the relation between megathrust ruptures and associated motion of upper-plate faults, we studied the El Yolki Fault (ELYF), a normal fault located near the region of lowest megathrust slip in 2010. We attempted to obtain the slip rate of the ELYF integrating field mapping of Holocene coastal landforms and combined airborne and terrestrial LiDAR data. In addition, paleoseismological trenches were dug along the uplifted footwall block where marine lagoonal sediments were back-tilted and uplifted by inferred slip along the ELYF. The trenches reveal basal metamorphic rocks and overlying fluvial sediments into which a stepped sequence of four distinct, decimeter-scale scarps had been sculpted at successively higher positions above bedrock. These erosional scarps are covered by a sequence of onlapping silty and clayey organic-rich intertidal sediments. In turn, these units are
Common catabolic enzyme patterns in a microplankton community of the Humboldt Current System off northern and central-south Chile: Malate dehydrogenase activity as an index of water-column metabolism in an oxygen minimum zone
González, R. R.; Quiñones, R. A.
An extensive subsurface oxygen minimum zone off northern and central-south Chile, associated with the Peru-Chile undercurrent, has important effects on the metabolism of the organisms inhabiting therein. Planktonic species deal with the hypoxic and anoxic environments by relying on biochemical as well as physiological processes related to their anaerobic metabolisms. Here we characterize, for the first time, the potential enzymatic activities involved in the aerobic and anaerobic energy production pathways of microplanktonic organisms (<100 μm), their relationship, and this relationship's association with the oxygen concentration and microplanktonic biomass in the oxygen minimum zone and adjacent areas of the Humboldt Current System water column. Our results demonstrate significant potential enzymatic activity of catabolic pathways in the oxygen minimum zone. Malate dehydrogenase had the highest oxidizing activity of nicotinamide adenine dinucleotide (reduced form) in the batch of catabolic enzymatic activities assayed, including potential pyruvate oxidoreductases activity, the electron transport system, and dissimilatory nitrate reductase. Malate dehydrogenase correlated significantly with almost all the enzymes analyzed within and above the oxygen minimum zone, and also with the oxygen concentration and microplankton biomass in the water column of the Humboldt Current System, especially in the oxygen minimum zone off Iquique. These results suggest a possible specific pattern for the catabolic activity of the microplanktonic realm associated with the oxygen minimum zone spread along the Humboldt Current System off Chile. We hypothesize that malate dehydrogenase activity could be an appropriate indicator of microplankton catabolism in the oxygen minimum zone and adjacent areas.
Le Roux, Jacobus P.; Achurra, Luciano; Henríquez, Álvaro; Carreño, Catalina; Rivera, Huber; Suárez, Mario E.; Ishman, Scott E.; Pyenson, Nicholas D.; Gutstein, Carolina S.
The stratigraphy of the Bahía Inglesa Formation in the Caldera Basin west of Copiapó, (north-central Chile) is revised, based on hitherto unpublished stratigraphic sections and 87Sr/86Sr dating. The depositional environment varied from a rocky shoreline to the upper continental slope, with sea-level oscillations and tectonic movements causing numerous local unconformities as well as lateral and vertical facies changes. Geohistory and sedimentological analyses show that the area was close to the concurrent sea level at about 15.3 Ma, but at the same time being elevated about 100 m above the present sea level. Although the basin then subsided at least 350 m until around 6 Ma, marine deposition was only recorded after 10.4 Ma. This suggests that the sea level initially dropped faster than the rate of subsidence so that subaerial erosion occurred. The period of subaerial exposure before 10.4 Ma can be attributed to the presence of a NE-trending branch of the Juan Fernández Ridge below the continental crust at this time, whereas the ensuing subsidence was due to subduction erosion and crustal accommodation in its wake as it migrated south along the South American coastline. The subsequent uplift of at least 250 m can be explained by an acceleration in plate expansion and isostatic rebound of the continental crust after being partially submerged in the upper mantle. The uplift-subsidence-uplift pattern mirrors those recorded around the Nazca Ridge in Peru, as well as in similar basins to the south of Caldera. However, a higher southward migration rate of the Juan Fernández Ridge against the edge of the South American Plate and less intense uplift-subsidence-uplift cycles are recorded in the latter basins. This can possibly be attributed to oroclinal bending of the ridge due to friction with the overlying continental plate, which diminished the angle of incidence and the intensity of the stress field, but increased the migration velocity of the ridge relative to the
Ayala, Alvaro; Pellicciotti, Francesca; MacDonell, Shelley; McPhee, James; Vivero, Sebastián; Campos, Cristián; Egli, Pascal
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
Boutonnet, E.; Arnaud, N.; Guivel, C.; Lagabrielle, Y.; Scalabrino, B.; Espinoza, F.
The Chile Triple Junction is a natural laboratory to study the interactions between magmatism and tectonics during the subduction of an active spreading ridge beneath a continent. The MLBA plateau (Meseta del Lago Buenos Aires) is one of the Neogene alkali basaltic plateaus located in the back-arc region of the Andean Cordillera at the latitude of the current Chile Triple Junction. The genesis of MLBA can be related with successive opening of slabs windows beneath Patagonia: within the subducting Nazca Plate itself and between the Nazca and Antarctic plates. Detailed 40Ar/ 39Ar dating and geochemical analysis of bimodal magmatism from the western flank of the MLBA show major changes in the back-arc magmatism which occurred between 14.5 Ma and 12.5 Ma with the transition from calc-alkaline lavas (Cerro Plomo) to alkaline lavas (MLBA) in relation with slab window opening. In a second step, at 4-3 Ma, alkaline felsic intrusions were emplaced in the western flank of the MLBA coevally with the MLBA basalts with which they are genetically related. These late OIB-like alkaline to transitional basalts were generated by partial melting of the subslab asthenosphere of the subducting Nazca plate during the opening of the South Chile spreading ridge-related slab window. These basalts differentiated with small amounts of assimilation in shallow magma chambers emplaced along transtensional to extensional zones. The close association of bimodal magmatism with extensional tectonic features in the western MLBA is a strong support to the model of Patagonian collapse event proposed to have taken place between 5 and 3 Ma as a consequence of the presence of the asthenospheric window (SCR-1 segment of South Chile Ridge) below the MLBA area.
Schuller, P; Walling, D E; Iroumé, A; Quilodrán, C; Castillo, A; Navas, A
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) (137)Cs and excess lead-210, the environmental radionuclides (226)Ra and (40)K 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
Mosolf, J.; Gans, P. B.; Wyss, A. R.; Cottle, J. M.
Many aspects of the long-term evolution of intra-arc processes remain poorly understood, including temporal trends in magmatism, temporal and spatial patterns of volcanism, and styles of arc deformation. The Abanico Formation in the Principal Cordillera of central Chile is a thick, well-exposed section of volcanogenic strata providing a superb locale for the investigation of continental arc dynamics over a 60+ myr timescale. In this study, eight new litho-stratigraphic members of the Abanico Formation are described and mapped in the Río Tinguiririca river area. Mapping and field observations show the Abanico Formation measures up to ~2.5 km in composite stratigraphic thickness. The lower ~1.1 km of the section (> 46 Ma) is dominated by andesitic breccias interbedded with andesite, basaltic andesite, and olivine basalt lavas. The upper 1.4 km of the section (< 46 Ma) consists of volcaniclastic sandstone interbedded with abundant dacitic tuffs and minor andesite, basaltic andesite, and basalt flows. Nineteen new LA-MC-ICPMS U-Pb zircon ages and ten new 40Ar/39Ar whole rock and plagioclase ages obtained for the Abanico Formation clarify ambiguous field relationships and provide a robust chrono-stratigraphic framework spanning ~72 to 11 Ma; these new ages significantly revise the maximum mid-Tertiary age for the Abanico Formation previously established by the mammal fossil record. The map units are cut by numerous dacitic to gabbroic dikes and sills with ages spanning the Eocene to Pliocene. The Abanico Formation is overlain in angular unconformity by Pliocene and Quaternary volcanics composed mainly of andesite, basaltic andesite, and basalt lavas. A strong deformational overprint has tilted, folded, and faulted the Abanico map units. Fold axes and reverse faults, both east and west directed, are generally N-S trending. Reverse faults achieve up to ~50 Ma of stratigraphic separation, placing Campanian strata on Miocene rocks with up to ~2 km of vertical throw. The
The Department of Geology and Geophysics, which is under the faculties of Mathematics and Physical Sciences of the University of Chile, is the organization that is responsible for the Seismological Service of Chile and for installing,operating, and maintaining the seismological stations as well as all the strong-motion stations in Chile.
Charrier, R.; Baeza, O.; Elgueta, S.; Flynn, J. J.; Gans, P.; Kay, S. M.; Muñoz, N.; Wyss, A. R.; Zurita, E.
The mainly volcanic Cenozoic deposits that make up much of the western part of the Principal Cordillera in Central Chile are generally subdivided into two major units: an older Abanico or Coya-Machalı´ Formation and a younger Farellones Formation. Difficulty in differentiating these units has led to considerable debate. On the basis of the wide distribution, great thickness, and presence of sedimentary intercalations, it has been postulated that these arc volcanics were deposited in an intermontane basin; more recently, it has been proposed that this basin developed under extensional conditions and underwent subsequent tectonic inversion. We present field, geochronologic, geochemical, and thermal maturity data that support the latter interpretation. Collectively, this new information clarifies the stratigraphic, tectonic, and paleogeographic evolution of these deposits. The vast geographic extent of the Abanico Formation and lateral equivalents, which reach from at least 32°30' to 44°S along the Principal Cordillera, its great thickness, and the presence of repeated thick fluvial and lacustrine intercalations all indicate deposition in a large, strongly subsident, and probably north-south oriented basin, developed between middle to late Eocene and Oligocene. The unconformable contact with underlying Mesozoic units observed at several localities indicates that deposition followed a substantial erosional episode during late Cretaceous and/or early Cenozoic time. Basal deposits of the Abanico Formation near Termas del Flaco increase rapidly in thickness to the west. Still further to the west, a thick Abanico section contains, in its upper part, mammal fossils older than those found in the basal deposits near Termas. This evidence indicates a major space of deposition west of this locality, which had been filled before deposition took place at Termas. The east-vergent, high-angle El Fierro thrust fault on the east side of the westward-growing deposits is
Toro, H; Pavez, E F; Gough, R E; Montes, G; Kaleta, E F
This study provides information on serology and serum chemistry of the Andean condor (Vultur gryphus). Twenty condors living under natural conditions were captured, blood sampled, measured, and released. In addition, 12 captive condors maintained at the Metropolitan Zoo of Santiago, Chile, were included as a comparison with free-living birds. All sera were negative to antibodies against reference strains of avian paramyxoviruses of serotypes 1 to 9, avian influenza and avian pox virus. Free-living condors had total protein, albumin, globulin and Mg values significantly (P< 0.05) lower than those of captive birds. The haematological values obtained in free-living condors are of particular interest since they may correspond to the optimum values of the species.
Drake, Paul W.
Annotated bibliography on the history of Chile during 60 years in the middle of the twentieth century is presented. A general outline of major Chilean developments during this period is presented to aid college level history instructors develop curriculum on Chile. Outline topics are the end of the Parliamentary Republic, 1920-31; popular front…
Bravo, Luis; Ramos, Marcel; Astudillo, Orlando; Dewitte, Boris; Goubanova, Katerina
Two physical mechanisms can contribute to coastal upwelling in eastern boundary current systems: offshore Ekman transport due to the predominant alongshore wind stress and Ekman pumping due to the cyclonic wind stress curl, mainly caused by the abrupt decrease in wind stress (drop-off) in a cross-shore band of 100 km. This wind drop-off is thought to be an ubiquitous feature in coastal upwelling systems and to regulate the relative contribution of both mechanisms. It has been poorly studied along the central-northern Chile region because of the lack in wind measurements along the shoreline and of the relatively low resolution of the available atmospheric reanalysis. Here, the seasonal variability in Ekman transport, Ekman pumping and their relative contribution to total upwelling along the central-northern Chile region (˜ 30° S) is evaluated from a high-resolution atmospheric model simulation. As a first step, the simulation is validated from satellite observations, which indicates a realistic representation of the spatial and temporal variability of the wind along the coast by the model. The model outputs are then used to document the fine-scale structures in the wind stress and wind curl in relation to the topographic features along the coast (headlands and embayments). Both wind stress and wind curl had a clear seasonal variability with annual and semiannual components. Alongshore wind stress maximum peak occurred in spring, second increase was in fall and minimum in winter. When a threshold of -3 × 10-5 s-1 for the across-shore gradient of alongshore wind was considered to define the region from which the winds decrease toward the coast, the wind drop-off length scale varied between 8 and 45 km. The relative contribution of the coastal divergence and Ekman pumping to the vertical transport along the coast, considering the estimated wind drop-off length, indicated meridional alternation between both mechanisms, modulated by orography and the intricate
Middle Proterozoic rocks underlying the Andes in western Bolivia, western Argentina, and northern Chile and Early Proterozoic rocks of the Arequipa massif in southern Peru?? from the Arequipa-Antofalla craton. These rocks are discontinuously exposed beneath Mesozoic and Cenozoic rocks, but abundant crystalline clasts in Tertiary sedimentary rocks in the western altiplano allow indirect samples of the craton. Near Berenguela, western Bolivia, the Oligocene and Miocene Mauri Formation contains boulders of granodiorite augen gneiss (1171??20 Ma and 1158??12 Ma; U-Pb zircon), quartzose gneiss and granofels that are inferred to have arkosic protoliths (1100 Ma source region; U-Pb zircon), quartzofeldspathic and mafic orthogneisses that have amphibolite- and granulite-facies metamorphic mineral assemblages (???1080 Ma metamorphism; U-Pb zircon), and undeformed granitic rocks of Phanerozoic(?) age. The Middle Proterozoic crystalline rocks from Berenguela and elsewhere in western Bolivia and from the Middle Proterozoic Bele??n Schist in northern Chile generally have present-day low 206Pb/204Pb ( 15.57), and elevated 208Pb/204Pb (37.2 to 50.7) indicative of high time-averaged Th/U values. The Middle Proterozoic rocks in general have higher presentday 206Pb/204Pb values than those of the Early Proterozoic rocks of the Arequipa massif (206Pb/204Pb between 16.1 and 17.1) but lower than rocks of the southern Arequipa-Antofalla craton (206Pb/204Pb> 18.5), a difference inferred to reflect Grenvillian granulite metamorphism. The Pb isotopic compositions for the various Proterozoic rocks lie on common Pb isotopic growth curves, implying that Pb incorporated in rocks composing the Arequipa-Antofalla craton was extracted from a similar evolving Pb isotopic reservoir. Evidently, the craton has been a coherent terrane since the Middle Proterozoic. Moreover, the Pb isotopic compositions for the Arequipa-Antofalla craton overlap those of the Amazon craton, thereby supporting a link
Orrego, R; Abarca-Del-Río, R; Ávila, A; Morales, L
Climate change scenarios are computed on a large scale, not accounting for local variations presented in historical data and related to human scale. Based on historical records, we validate a baseline (1962-1990) and correct the bias of A2 and B2 regional projections for the end of twenty-first century (2070-2100) issued from a high resolution dynamical downscaled (using PRECIS mesoscale model, hereinafter DGF-PRECIS) of Hadley GCM from the IPCC 3rd Assessment Report (TAR). This is performed for the Araucanía Region (Chile; 37°-40°S and 71°-74°W) using two different bias correction methodologies. Next, we study high-resolution precipitations to find monthly patterns such as seasonal variations, rainfall months, and the geographical effect on these two scenarios. Finally, we compare the TAR projections with those from the recent Assessment Report 5 (AR5) to find regional precipitation patterns and update the Chilean `projection. To show the effects of climate change projections, we compute the rainfall climatology for the Araucanía Region, including the impact of ENSO cycles (El Niño and La Niña events). The corrected climate projection from the high-resolution dynamical downscaled model of the TAR database (DGF-PRECIS) show annual precipitation decreases: B2 (-19.19 %, -287 ± 42 mm) and A2 (-43.38 %, -655 ± 27.4 mm per year. Furthermore, both projections increase the probability of lower rainfall months (lower than 100 mm per month) to 64.2 and 72.5 % for B2 and A2, respectively.
Flewett, Samuel; Saintenoy, Thibault; Sepúlveda, Marcela; Mosso, Edward Fabian; Robles, Carolina; Vega, Katherine; Gutierrez, Sebastian; Romero, Alvaro; Finney, Lydia; Maxey, Evan; Vogt, Stefan
Archeological ceramic paste material typically consists of a mix of a clay matrix and various millimeter and sub-millimeter sized mineral inclusions. Micro X-ray fluorescence (XRF) is a standard compositional classification tool and in this work we propose and demonstrate an improved fluorescence map processing protocol where the mineral inclusions are automatically separated from the clay matrix to allow independent statistical analysis of the two parts. Application of this protocol allowed us to enhance the discrimination between different ceramic shards compared with the standard procedure of working with only the spatially averaged elemental concentrations. Using the new protocol, we performed an initial compositional classification of a set of 83 ceramic shards from the western slopes of the south central Andean region in the Arica y Parinacota region (Chile). Comparing the classifications obtained using the new versus the old (average concentrations only) protocols, we found that some samples were erroneously classified with the old protocol. From an archaeological perspective, a broad and heterogeneous regional sample set was used in this experimental study due to the fact that this was the first such analysis to be performed on ceramics from this region. This allowed a general overview to be obtained, however further work on more specific sample sets will be necessary to extract concrete archaeological conclusions.
Pardo, M.; Monfret, T.; Vera, E.; Yañez, G.; Eisenberg, A.
Based on data from a dense local temporary seismological network, crustal seismicity is characterized, and a 3- D body wave velocity structure is obtained by tomographic inversion down to the subducted slab. In the framework of Fondecyt 1050758, GeoAzur-IRD and ACT-18 projects, 35 broadband and short period instruments, were deployed in the studied zone for 135 days recording in continuous mode. At this zone the Andean active volcanism reappears after a gap of volcanic activity since late Miocene occurring north of 33 S due to the Central Chile flat slab subduction zone. Crustal seismicity in the depth range 0-30 km is well correlated with known geological faults that become now important in the assessment of the regional seismic hazard. This seismicity also clusters around the giant porphyry cooper deposits in the region (Rio Blanco, El Teniente), and are neither related to mine-blasts nor induced by mining activity. Moreover, the local 3-D velocity structure shows that the zone surrounding each deposit is characterized by high Vp/Vs greater than 1.8, which may indicate fluid phases located in the weakest and more fractured zone of the crust. The body wave velocity pattern shown at depth by the local tomography indicates channels of high Vp/Vs connecting the subducted slab with the surface at places where active volcanism is present, suggesting upward migration of hydrous or melted rocks. This pattern agrees with the one observed with a previous regional tomography that includes this zone, while this Vp/Vs pattern tends to be horizontal at the flat slab zone. At depths of 20-25 km, a layer of high Vp/Vs is observed beneath the Andes Cordillera that could be associated to changes in the rheological properties between the upper and lower crust, or to accumulation of magma. The average stress tensor, derived from focal mechanisms, indicate that the Andean zone is under compression in the plate convergence direction.
Classification of Debris-Covered Glaciers and Rock Glaciers in the Andes of Central Chile - An Approach Integrating Field Measurements, High-Resolution Satellite Imagery, and Coring Data to Estimate Water Resources
Janke, J. R.; Bellisario, A. C.; Ferrando, F. A.
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. These landforms are more numerous than glaciers in the Central Andes; however, there are often omitted from inventories. Glaciers, debris covered glaciers, and rock glaciers are being removed by mining, while agricultural expansion and population growth have placed an additional demand on water resources. As a result, it is important to identify and locate these features to implement sustainable solutions. The objective of this study is to develop a classification system to identify debris-covered glaciers and rock glaciers based on satellite imagery interpretation. 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. 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 transverse ridges and furrows that arch across the surface, which indicate flow produce via ice. Class 5 rock glaciers have ridges and furrows that appear linear in the direction of flow, and Class 6 rock glaciers have subdued surface topography that has been denudated as the rock glacier ceases movement. Ice content decreases from 25-45% ice, to 10-25% ice, to less than 10% ice from Class 4 to 6, respectively. The classification scheme can be used to identify and map debris covered glaciers and rock glaciers to create an inventory to better estimate available water resources at the basin-wide scale.
Parra, Amparo; Oyarzún, Jorge; Maturana, Hugo; Kretschmer, Nicole; Meza, Francisco; Oyarzún, Ricardo
This contribution analyzes water chemical data for the Choapa basin, North Central Chile, for the period 1980-2004. The parameters considered are As, Cu Fe, pH, EC, SO₄⁻², Cl⁻¹, and HCO[Formula: see text], from samples taken in nine monitoring stations throughout the basin. Results show rather moderate contents of As, Cu, and Fe, with the exception of the Cuncumén River and the Aucó creek, explained by the influence of the huge porphyry copper deposit of Los Pelambres and by the presence of mining operations, respectively. When compared against results obtained in previous researches at the neighboring Elqui river basin, which host the El Indio Au-Cu-As district, a much reduced grade of pollution is recognized for the Choapa basin. Considering the effect of acid rock drainage (ARD)-related Cu contents on the fine fraction of the sediments of both river basins, the differences recorded are even more striking. Although the Los Pelambres porphyry copper deposit, on the headwaters of the Choapa river basin, is between one and two orders of magnitude bigger than El Indio, stream water and sediments of the former exhibit significantly lower copper contents than those of the latter. A main factor which may explain these results is the smaller degree of H( + )-metasomatism on the host rocks of the Los Pelambres deposit, where mafic andesitic volcanic rocks presenting propylitic hydrothermal alteration are dominant. This fact contrast with the highly altered host rocks of El Indio district, where most of them have lost their potential to neutralize ARD.
Available from <http://www.rr.ee.gov.bo/ministerio/ POLITICA EXTERIOR /memoria.htm >. Internet. Accessed 28 October 2004. Gray, Colin. “Thinking...Bolivia’s gas to Mexico and North America. Chile’s President Lagos likewise invited Bolivia to construct a plant in Chile to facilitate gas production at
Guillou, Michèle; Carabantes C, Jorge; Bustos F, Verónica
The availability and planning of Human Resources are important issues in many countries, as it is a key factor to cope with the critical challenges of Health Care Systems. In Chile, the Ministry of Health has undertaken several studies in order to improve knowledge about the medical workforce both in public and private sectors. The aim of this paper is to update and systematize the existing data on physicians and specialists availability in Chile. Several information sources were crossed to obtain new and more precise figures about this topic. According to the Internal Revenue System, 29.996 physicians practice medicine in the country, 43% of them hired in public services, part or full time. There is a high concentration of professionals in the central regions of Chile. Being the overall density of physicians of one per 559 inhabitants, the figures in the central region is one per 471 and one per more than 800 in the South and North. Between 2004 and 2008, the public sector increased its physician workforce by more than 80% in primary health care and more than 20% in the secondary and tertiary levels. This paper presents a method for a more rigorous identification of the categories of general practitioner and specialist respectively, and the results obtained from the databases used.
Late Paleozoic onset of subduction and exhumation at the western margin of Gondwana (Chilenia Terrane): Counterclockwise P-T paths and timing of metamorphism of deep-seated garnet-mica schist and amphibolite of Punta Sirena, Coastal Accretionary Complex, central Chile (34° S)
Hyppolito, T.; García-Casco, A.; Juliani, C.; Meira, V. T.; Hall, C.
In this study, the Paleozoic albite-epidote-amphibolite occurring as meter-sized intercalations within garnet-mica schist at Punta Sirena beach (Pichilemu region, central Chile) is characterized for the first time. These rocks constitute an unusual exposure of subduction-related rocks within the Paleozoic Coastal Accretionary Complex of central Chile. Whereas high pressure (HP) greenschist and cofacial metasediments are the predominant rocks forming the regional metamorphic basement, the garnet-mica schist and amphibolite yield higher P-T conditions (albite-epidote amphibolite facies) and an older metamorphic age. Combining detailed mineral chemistry and textural information, P-T calculations and Ar-Ar ages, including previously published material from the Paleozoic Accretionary Complex of central Chile, we show that the garnet-mica schist and associated amphibolite (locally retrograded to greenschist) are vestiges of the earliest subducted material now forming exotic bodies within the younger HP units of the paleo-accretionary wedge. These rocks are interpreted as having been formed during the onset of subduction at the southwestern margin of Gondwana. However, we show that the garnet-mica schist formed at a slightly greater depth (ca. 40 km) than the amphibolite (ca. 30 km) along the same hot-subduction gradient developed during the onset of subduction. Both lithotypes reached their peak-P conditions at ca. 335-330 Ma and underwent near-isobaric cooling followed by cooling and decompression (i.e., counterclockwise P-T paths). The forced return flow of the garnet-mica schist from the subduction channel started at ca. 320 Ma and triggered the exhumation of fragments of shallower accreted oceanic crust (amphibolite). Cores of phengite (garnet-mica schist) and amphibole (amphibolite) grains have similar chemical compositions in both the S1 and S2 domains, indicating rotation of these grains during the transposition of the burial-related (prograde peak-T) foliation S1
Bahlburg, Heinrich; Spiske, Michaela
The style of early diagenesis and preservation of onshore tsunami deposits are poorly constrained. Only tsunami surveys and subsequent re-surveys can fill this information gap. Here we present the results of a first re-survey in 2012 on Isla Mocha following the original survey in 2010 in the wake of the February 27, 2010, Maule earthquake and tsunami in central Chile. As a result of this tsunami, a large number of boulders consisting of clay-rich fine sandstones representing the Miocene age bedrock of the island had been transferred from the tidal to shallow subtidal zone onto the coastal plain. Coarse clastic sediment mixtures of pebbles, granules, and sand entrained at coastal plain terraces and transported up to the maximum runup position c. 600 m from the coast by the inflow had been left behind as extensive backflow blankets on the lower coastal plain. In 2012, vegetation had covered the 2010 tsunami deposits. Sediment beyond 200 m from the coast had been removed by a combination of surface processes and grazing cattle. Grain-size distributions of the preserved sediment show an increase of the sand fraction at the expense of the coarser grain sizes. Boulders show patterns resembling mud cracks on the surface and evidence of disintegration into smaller fragments and sand. Veneers of dried algae documenting the derivation of the boulders from the tidal zones had flaked off partly or completely from most rock surfaces. At the northern, wind-facing coast of the island, a c. 130 m long and 1.2 m high beach ridge had accumulated, most likely from reworked tsunami sediment. Boulders deposited by tsunamis are commonly assigned a high preservation potential. We demonstrate for the first time that such boulders may in fact disintegrate rapidly and disappear from the record over short geological time scales, given a lithology susceptible to weathering. The degree of modification to the lsla Mocha tsunami boulders and deposits strongly questions the applicability of
Marot, M.; Monfret, T.; Gerbault, M.; Nolet, G.; Ranalli, G.; Pardo, M.
Our study compares the seismic properties between the flat and normal subduction regions in central Chile, to better understand the links between the slab geometry, surface deformation and the deeper structures. In comparison with previous studies, we show the most complete 3-D regional seismic tomography images for this region, in which we use (1) a larger seismic data set compiled from several short-term seismic catalogues, (2) a denser seismic array allowing a better resolution of the subduction zone from the trench to the backarc and into the upper ˜30 km of the slab and (3) a starting 1-D background velocity model specifically calculated for this region and refined over the years. We assess and discuss our tomography results using regional seismic attenuation models and estimating rock types on the basis of pressure and temperature conditions computed from thermomechanical models. Our results show significant seismic differences between the flat and normal subduction zones. As expected, the faster seismic velocities and increased seismicity within the flat slab and overriding lithosphere are generally consistent with a cooler thermal state. Our results are also consistent with dehydration of the mantle above the subducted Juan Fernandez Ridge at the eastern tip of the flat slab segment, indicating that the latter retains some fluids during subduction. However, fluids in the upper portion of the flat slab segment are not seismically detected, since we report instead fast slab seismic velocities which contradict the argument of its buoyancy being the cause of horizontal subduction. The forearc region, above the flat slab, exhibits high Vs and very low Vp/Vs ratios, uncorrelated with typical rock compositions, increased density or reduced temperature; this feature is possibly linked with the aftershock effects of the Mw7.1 1997 Punitaqui earthquake, the flat slab geometry and/or seismic anisotropy. At the surface, the seismic variations correlate with the
Carrasco M, Víctor Hugo; Crispi, Francisca
Euthanasia is a complex medical procedure. Even though end of life decisions are common situations in health practice, there is a lack of consensus about their terminology. In this manuscript, the main concepts about this issue are defined and delimited; including active and passive euthanasia and limitation of therapeutic effort. Then, a revision is made about the international experience on euthanasia, to then go through the Chiles history in euthanasia and the populations opinion. In Chile, euthanasia is an act that has been removed from the social dialogue and legislation. In order to have an open discussion in our population about the issue, the debate has to be opened to the citizens, accompanied by clear medical information about the procedure.
The Mw=8.8 earthquake off the coast of Chile on 27 February 2010 is the 5th largest megathrust earthquake ever to be recorded and provides an unprecedented opportunity to advance our understanding of megathrust earthquakes and associated phenomena. The 2010 Chile earthquake ruptured the Concepcion-Constitucion segment of the Nazca/South America plate boundary, south of the Central Chile region and triggered a tsunami along the coast. Following the 2010 earthquake, a very energetic aftershock sequence is being observed in an area that is 600 km along strike from Valparaiso to 150 km south of Concepcion. Within the first three weeks there were over 260 aftershocks with magnitude 5.0 or greater and 18 with magnitude 6.0 or greater (NEIC, USGS). The Concepcion-Constitucion segment lies immediately north of the rupture zone associated with the great magnitude 9.5 Chile earthquake, and south of the 1906 and the 1985 Valparaiso earthquakes. The last great subduction earthquake in the region dates back to the February 1835 event described by Darwin (1871). Since 1835, part of the region was affected in the north by the Talca earthquake in December 1928, interpreted as a shallow dipping thrust event, and by the Chillan earthquake (Mw 7.9, January 1939), a slab-pull intermediate depth earthquake. For the last 30 years, geodetic studies in this area were consistent with a fully coupled elastic loading of the subduction interface at depth; this led to identify the area as a mature seismic gap with potential for an earthquake of magnitude of the order 8.5 or several earthquakes of lesser magnitude. What was less expected was the partial rupturing of the 1985 segment toward north. Today, the 2010 earthquake raises some disturbing questions: Why and how the rupture terminated where it did at the northern end? How did the 2010 earthquake load the adjacent segment to the north and did the 1985 earthquake only partially ruptured the plate interface leaving loaded asperities since
Martin, Mark W.; Kato, Terence T.; Rodriguez, Carolina; Godoy, Estanislao; Duhart, Paul; McDonough, Michael; Campos, Alberto
Stratigraphic, structural, metamorphic, and geochronologic studies of basement rocks in the Andean foothills and Coast Ranges of south central Chile (39°-41°S) suggest a protracted late Paleozoic to middle Mesozoic deformational and metamorphic history that imposes important constraints on the tectonic development of the southwestern Gondwana margin. In the study area the late Paleozoic paired metamorphic belt, coeval magmatic arc, and overlying Triassic sedimentary units preserve a record of Late Carboniferous to Early Permian subduction and arc magmatism, subsequent deep exhumation of the Western Series subduction complex, and diminished uplift and erosion of the Eastern Series arc-forearc region by the Late Triassic. Late Paleozoic structural elements and metamorphic assemblages formed during early subduction and arc magmatism, collectively referred to as Dl, are largely erased in the Western Series by the dominant D2 schistosity and lower greenschist grade metamorphism. D1 structural features, as well as original sedimentary textures, are relatively well preserved in the less penetratively deformed Eastern Series. The regional distribution of late Paleozoic arc magmatism suggests that the late Paleozoic convergent margin deviated from a N-S trend north of this area to a NW-SE trend near this latitude and faced an open marine environment to the southwest. A transition from F2 isoclinal folding to more open, larger-scale F3 folds, interpreted as change in ductility during differential uplift of the Western Series, is not apparent in the Eastern Series. Despite a lesser degree of uplift during the main exhumational D2 event, delineation of unconformities and U-Pb dating of detrital zircons and intrusions into the Eastern Series allow tighter constraints to be placed on timing of uplift and denudation of the Eastern Series than on that in the Western Series. A regional unconformity exposed in the Lake District that separates more highly deformed Eastern Series
Boutonnet, Emmanuelle; Arnaud, Nicolas; Guivel, Christèle; Lagabrielle, Yves; Scalabrino, Bruno; Espinoza, Felipe
The Chile Triple Junction is a natural laboratory to study the interactions between magmatism and tectonics during the subduction of an active spreading ridge beneath a continent. The MLBA plateau (Meseta del Lago Buenos Aires) is one of the Neogene alkali basaltic plateaus located in the back-arc region of the Andean Cordillera at the latitude of the current Chile Triple Junction. The genesis of MLBA can be related with successive opening of slabs windows beneath Patagonia: within the subducting Nazca Plate itself and between the Nazca and Antarctic plates. Detailed 40Ar/39Ar dating and geochemical analysis of bimodal magmatism from the western flank of the MLBA show major changes in the back-arc magmatism which occurred between 14.5 Ma and 12.5 Ma with the transition from calc-alkaline lavas (Cerro Plomo) to alkaline lavas (MLBA) in relation with slab window opening. In a second step, at 4- 3 Ma, alkaline felsic intrusions were emplaced in the western flank of the MLBA coevally with the MLBA basalts with which they are genetically related. These late OIB-like alkaline to transitional basalts were generated by partial melting of the subslab asthenosphere of the subducting Nazca plate during the opening of the South Chile spreading ridge-related slab window. These basalts differentiated with small amounts of assimilation in shallow magma chambers emplaced along transtensional to extensional zones. The close association of bimodal magmatism with extensional tectonic features in the western MLBA is a strong support to the model of Patagonian collapse event proposed to have taken place between 5 and 3 Ma as a consequence of the presence of the asthenospheric window (SCR-1 segment of South Chile Ridge) below the MLBA area.
Farías, Laura; Cornejo, Marcela
An intensive and seasonal coastal upwelling process, which attains maximal expression during late austral spring and summer, drives well-known changes in organic matter production and, therefore, in O 2 content in the water column. These variables have a concomitant effect on N sediment processes over the continental shelf off central Chile (36.5°S), which, in turn, can affect the NO3-, NO2-, and N 2O content in the bottom water. Hydrographic characteristics, benthic NO3- and NO2- fluxes, and denitrification rates were measured from 1998 to 2001 (with at least seasonal frequency). In order to elucidate how benthic N 2O recycling responds to different O 2 and nutrient levels and how it affects the bottom water N 2O content, net N 2O cycling was measured in December 2001 in sediment slurry incubations under different manipulated dissolved O 2 levels (anoxic: 0 μM; hypoxic: 22.3 μM; oxic: 44.6 μM) and without (natural) and with the addition of NO3- and NH4+ (enriched experiments). Dissolved O 2 and NO3- contents (and also PO43-) showed clear seasonal patterns according to the oceanographic regime, i.e., from hypoxic waters rich in nutrients during the upwelling season to oxic waters with less nutrient contents during the non-upwelling season. The bottom water, on the other hand, was influenced by benthic organic mineralization, which consumes O 2 as well as other electron acceptor N-species such as NO3-. Benthic NO3- fluxes (2.62-5.08 mmol m -2 d -1) were always directed into the sediments, whereas denitrification rates varied from 0.6 to 2.9 mmol m -2 d -1. N 2O was also consumed at rates of 5.53 and 4.56 μmol m -2 d -1 under anoxia and hypoxia, but N 2O consumption rates were reduced to almost half under oxic conditions in both natural and a NH4+-enriched experiments. With the NO3--enriched experiments, however, N 2O consumption was very high (up to 24.25 μmol m -2 d -1) under anoxic and hypoxic conditions, suggesting that high NO3- levels induce more N 2O
The first case of AIDS in Chile was diagnosed in 1984. There have been 1060 cases reported since then throughout the country, or 8.2 cases for every 100,000 Chileans. 92.8% of all people with AIDS in Chile are male, with the male:female AIDS patient ratio increasing from 12.9:1 for the period 1984-1991 to 15.2:1 currently. This increase in the proportion of male AIDS cases suggests the existence of a rapidly increasing male HIV infection rate. 82% of reported cases are the result of unprotected sexual intercourse, 66.8% of which are among males who identify themselves as homosexual or bisexual. The 7.2:1 ratio of homosexual/bisexual transmission to heterosexual transmission for 1984-1989, however, declined to 3.9:1 for 1990-1994, indicating an increase in the extent of HIV/AIDS transmission through sex between men and women. Heterosexual sex is the reported means of transmission for 15.2% of currently identified AIDS cases in Chile. The mode of transmission was unknown for 10% of reported cases, due to vertical transmission among 1%, and the result of the direct exchange of blood among 7%. 60% of these latter cases were reported among IV drug users, 20% were reported as the result of blood transfusion, and 16% were reported in hemophiliacs. Most transmissions by blood transfusion occurred before 1987, when blood product controls were implemented. Infection due to IV drug use grew to 69.8% of such blood-related cases in 1990-94, compared to just 29.4% of cases in 1984-89. 81.5% of all cases are among people aged 20-49 years, with 64.1% of cases among individuals aged 30-49. Those under age 20 comprise 2.3% of total cases and those aged 20-29 years comprise 17.4%.
The author describes a joint program to use renewables for rural electrification projects in Chile. The initial focus was in a limited part of the country, involving wind mapping, pilot project planning, training, and development of methodologies for comparative evaluations of resources. To this point three wind hybrid systems have been installed in one region, as a part of the regional private utility, and three additional projects are being designed. Additional resource assessment and training is ongoing. The author points out the difficulties in working with utilities, the importance of signed documentation, and the need to look at these programs as long term because of the time involved in introducing such new technologies.
... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Chiles Valley. 9.154... Chiles Valley. (a) Name. The name of the viticultural area described in this section is “Chiles Valley.” (b) Approved maps. The appropriate maps for determining the boundary of the Chiles...
Sodoudi, F.; Asch, G.; Kind, R.; Oncken, O.; Vilotte, J.; Barrientos, S. E.; Salazar Reinoso, P.
Installation of observatories in northern Chile started in 2006 in a close cooperation of the Universidad de Chile (Santiago), the Universidad Catolica del Norte (Antofagasta), the IPGP (Paris), and the GFZ Potsdam. Currently we operate 16 modern seismological stations equipped with STS-2 broadband seismometers. All seismic stations are located in northern Chile at 19°-24° S between Arica in the North and Antofagasta in the South. Due to the large amount of the available data, it is now possible to obtain detailed geometry of the subducting Nazca plate as well as that of the continental South American plate in northern Chile with so far unprecedented resolution. The lower boundary of the lithospheric plates, which is poorly observed by seismic means, has remained as an exotic boundary. Even though, seismic surface waves can image the asthenosphere as a low velocity zone. The Lithosphere-Asthenosphere Boundary (LAB) resolved by surface waves can be only considered as a broad transition zone due to the large wavelength of the surface waves. Seismic techniques which use converted body waves are now far enough developed to be successful in observing the LAB with a higher resolution than known so far. The principle of the receiver function technique is that a strong teleseismic mother phase (e.g. P or S) incident on the discontinuity beneath a station produces a small converted phase (P-to-S or S-to-P) which indicates its properties. We combined here these two methods (P and S receiver function) to have the best vertical as well as horizontal coverage of the area. P receiver function analysis using P-to-S converted waves was used as the main tool to map the crustal structure. More than 120 P receiver functions obtained from each station enabled us to detect even small azimuthal structural differences. While P receiver functions provided a clear Image of the Moho topography, S receiver functions (using S-to-P converted waves) were used to detect the Lithosphere
On February 5, 2002, the dense smoke from numerous forest fires stretched out over the Pacific Ocean about 400 miles south of Santiago, Chile. This true-color Moderate-resolution Imaging Spectroradiometer (MODIS) image shows the fires, which are located near the city of Temuco. The fires are indicated with red dots (boxes in the high-resolution imagery). The fires were burning near several national parks and nature reserves in an area of the Chilean Andes where tourism is very popular. Southeast of the fires, the vegetation along the banks of the Rio Negro in Argentina stands out in dark green. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC
Calvin, M E
The Evangelical Lutheran Church of Chile's Program for Health Education (EPES) has developed HIV/AIDS and reproductive health education seminars for residents of working class neighborhoods in Santiago and Concepcion. A 1996 seminar on violence and AIDS, organized by EPES in collaboration with a network of area schools, health centers, and nongovernmental organizations, was attended by 250 women. Subsequent workshops have addressed homosexuality and lesbianism, women and AIDS, sex workers and AIDS, sex education, domestic violence, and child sex abuse. These workshops have included skills-building sessions on safer sex, prevention of domestic violence, stress management, women's self-defense, and AIDS education techniques. Workshop participants are urged to distribute AIDS educational materials and help the network organize exhibits at public events. In the future, EPES plans to conduct outreach to men as well as women.
ESO, the European Southern Observatory, in reply to questions raised by the international media, as well as an ongoing debate about the so-called "Paranal case" in Chilean newspapers, would like to make a number of related observations concerning its status and continued operation in that country . THE ESO OBSERVATORY SITES IN CHILE The European Southern Observatory, an international organisation established and supported by eight European countries, has been operating more than 30 years in the Republic of Chile. Here ESO maintains one of the world's prime astronomical observatories on the La Silla mountain in the southern part of the Atacama desert. This location is in the Fourth Chilean Region, some 600 km north of Santiago de Chile. In order to protect the La Silla site against dust and light pollution from possible future mining industries, roads and settlements, ESO early acquired the territory around this site. It totals about 825 sq. km and has effectively contributed to the preservation of its continued, excellent "astronomical" quality. Each year, more than 500 astronomers from European countries, Chile and elsewhere profit from this when they come to La Silla to observe with one or more of the 15 telescopes now located there. In 1987, the ESO Council  decided to embark upon one of the most prestigious and technologically advanced projects ever conceived in astronomy, the Very Large Telescope (VLT). It will consist of four interconnected 8.2-metre telescopes and will become the largest optical telescope in the world when it is ready. It is safe to predict that many exciting discoveries will be made with this instrument, and it will undoubtedly play a very important role in our exploration of the distant universe and its many mysteries during the coming decades. THE VLT AND PARANAL In order to find the best site for the VLT, ESO performed a thorough investigation of many possible mountain tops, both near La Silla and in Northern Chile. They showed
Confidentiality is a critical issue in the conduct of HIV tests in Chile. Though HIV testing is confidential in the public health system (through the use of a coding system), syphilis tests which are conducted simultaneously with HIV, require clients to provide their identity as well as address. In response to this concern, the National AIDS Commission has launched training programs in all 26 public health services for staff involved with HIV/AIDS programs. The training programs allow professional staff and volunteers to understand the importance of confidentiality. Nevertheless, cases of breaches of confidentiality have been reported, raising doubts as to the ability of the system to maintain confidentiality. These cases often occur at the hospitals or clinics where staff is insensitive to the needs of their clients and oblivious of their rights. Hence, it is highlighted that to reinforce confidentiality, patients, advocacy groups, human rights activists and health care administrators must pay attention to the many ways in which confidentiality is breached.
Montoya Leiva, M
Servicio Paz y Justicia (SERPAJ) is a nongovernmental organization (NGO) established in Chile in 1977. It supports fundamental human dignity and rights by fighting discrimination and exclusion based upon individual differences. SERPAJ promotes training, organization, and the political participation of community members as part of the democratic process, working mainly with the at risk women, street children, and youth of Santiago's working-class neighborhoods. Groups participate in workshops and training courses on human rights and development, civic education, and methods of non-violent community action. In 1987, SERPAJ-Sur Oriente began to include the topic of sexuality and AIDS/STDs in courses training working-class women as community human rights agents. The NGO is therefore one of the first mainstream Chilean human rights organizations to incorporate HIV/AIDS issues. A basic facts brochure was developed, followed by a pilot education project developed in one neighborhood which was then systematically replicated in other neighborhoods. The comments of some people who have participated in SERPAJ workshops are presented.
Hahn Ibanez, M
In anticipation of social discrimination, an estimated 65% of parents of HIV-infected children in Chile do not inform school authorities of their child's infection. In several well-publicized cases, disclosure of a child's HIV status resulted in the child's expulsion from a preschool or primary school. In response to this situation, the Faculty of Education of Bias Canas Catholic University launched a program in 1992 aimed at educating teachers about HIV/AIDS and the special needs of infected children. The program is being implemented, in conjunction with the Interdisciplinary Project on Children and HIV/AIDS, in the cities with the highest HIV prevalences: Antafagasta, Concepcion, Valparaiso, and Santiago. Community-based educational programs have been organized to dispel misinformation about HIV/AIDS and counter prejudice. In addition, programs for teachers focused on the integration of HIV-infected children into the school system have been held. Costs for the teacher training are shared by the participating teachers, their school, and the program. A second program--Integral Attention for Seropositive Children--has been initiated and university students connected to the program are serving as interns in Santiago preschools. The experiences of both these programs have been recounted in a manual and video.
Reyes B, Humberto
One of the biggest earthquakes recorded in human history has recently devastated a large part of the Chilean territory and, followed by a Tsunami, destroyed cities, seaports, fishermen's coves, bridges, and countryside houses. This cataclysm affected a large proportion of our population, leaving homeless families, no working tools for work places, hospitals, schools, public buildings, museums. However, the loss of human Uves was small compared to similar disasters. It destroyed part of the national heritage as well as damaged people's living conditions. A national movement started immediately to help and recover, and international resources, both human and technological were also set in motion. As after previous earthquakes in Chile, young M.D.'s and medical students were organized in voluntary groups backed by institutions or by their own organizations and went from large cities as Santiago and others to provide medical and psychological care to those in most need. Young members and students of other health professions (nurses, physical therapists, etc.) were included in these groups or worked in their own ones. National and international experience indicates that the forthcoming months require special care of psychological reactions and sequel (posttraumatic stress symptoms) and health consequences after water pollution, restrictions in housing and deteriorated sanitary conditions. Nevertheless, our country will stand up once more.
Carretier, Sebastien; Tolorza, Violeta; Regard, Vincent; Riquelme, Rodrigo; Aguilar, German
Erosion and sediment transport in arid environments is thought to depend on the frequency of large floods as well as on mean precipitation rate and slope, but their relative impact remains a matter of active debate. The Chilean Andes are elongated along a sharp precipitation rate gradient, offering the possibility to rank these factors over different time spans. We compare suspended load measurements-derived decennial erosion rates and 10Be-derived millennial erosion rates along this gradient. Both parameters follow the same latitudinal trend and peak where the climate is Mediterranean (mean runoff ~0.55 m/m), confirming that slope is the main factor even along this contrasted climate. The comparison of these erosion rates documents the progressive contribution of rare and strong climatic events on the millennial erosion from humid to arid catchments. In the wetter BíoBio catchment, the separation of suspended sediment yield during base and direct flows shows that the dynamics of groundwater circulation controls most of the sediment hysteresis at gauging stations at annual scale. In addition, the mega El Maule earthquake (Mw8.8 in 2010), in front of humid to semi-arid catchments, has not increased the suspended sediment concentration in rivers, excepted in the steepest and driest catchments. Over millennial scales, preliminary 10Be concentrations in individual gravels and cobbles suggest mean river transport rates of several m/yr in an arid canyon of north Chile.
de Jesús Luna-Ruíz, José; Gepts, Paul
Different Seed Selection and Conservation Practices for Fresh Market and Dried Chile Farmers in Aguascalientes, Mexico. The process of selecting and saving seed is the most basic and oldest of agricultural practices. In today’s modern and highly capital-intensive agriculture, seeds are often treated like another chemical input. This study sought to examine seed selection and saving practices among chile farmers in Aguascalientes, Mexico, where both industrial and traditional agriculture are practiced. We observed a clear division among farmers who plant chile peppers commercially. Sixty-eight chile pepper farmers were surveyed in order to document seed selection and saving practices. Fifteen respondents (22%) planted chile peppers destined for the fresh market and all utilized purchased commercial seed of F1 hybrid varieties. Fifty-three farmers (78%) planted chiles to be dried and either saved their own or purchased seeds that others had saved and selected. Farmers who saved their own seed sought to maintain an ideotype, rather than directionally select for certain traits, much like Cleveland et al. (2000) chronicled in central Mexican maize farmers. Farmers would benefit from a participatory plant-breeding program in order to maintain productive seed stock for the continued cultivation of dried chile pepper in the state. PMID:21212817
In Chile there are six established medical schools at public (Chile, Valparaiso and Temuco) or private (Catholic, Concepción and Austral) universities created between 1833 and 1971. Since 1990, three new medical schools (two private) were created and a fourth is projected, concerning the chilean medical corps. We present three position articles on the subject written by Dean Pedro Rosso, from the Catholic University, Dr Pedro Castillo, Chief of Human Resources of the Ministry of Health and Dean Alejandro Goic from the University of Chile. Dean Rosso emphasizes the need to have assessment procedures that guarantee quality standards in the new medical schools. Dr Castillo attracts attention on preserving the compromise with the society, inherent to chilean medicine. Dean Goic analyzes systematically the reasons to prevent the proliferation of medical schools in the country, maintaining an equilibrium between freedom of teaching and public faith protection.
Úbeda, Xavier; Sarricolea, Pablo
This paper reviews the literature examining the wildfire phenomenon in Chile. Since ancient times, Chile's wildfires have shaped the country's landscape, but today, as in many other parts of the world, the fire regime - pattern, frequency and intensity - has grown at an alarming rate. In 2014, > 8000 fires were responsible for burning c. 130,000 ha, making it the worst year in Chile's recent history. The reasons for this increase appear to be the increment in the area planted with flammable species; the rejection of these landscape modifications on the part of local communities that target these plantations in arson attacks; and, the adoption of intensive forest management practices resulting in the accumulation of a high fuel load. These trends have left many native species in a precarious situation and forest plantation companies under considerable financial pressure. An additional problem is posed by fires at the wildland urban interface (WUI), threatening those inhabitants that live in Chile's most heavily populated cities. The prevalence of natural fires in Chile; the relationship between certain plant species and fire in terms of seed germination strategies and plant adaptation; the relationship between fire and invasive species; and, the need for fire prevention systems and territorial plans that include fire risk assessments are some of the key aspects discussed in this article. Several of the questions raised will require further research, including just how fire-dependent the ecosystems in Chile are, how the forest at the WUI can be better managed to prevent human and material damage, and how best to address the social controversy that pits the Mapuche population against the timber companies.
Investigations Police of Chile (Policia de Investigaciones de Chile – PDI). Carabineros de Chile is the uniformed Chilean national police force created in...Chile also has an investigative police force, the Investigations Police of Chile (Policia de Investigaciones de Chile, PDI). This is the civil police... Investigaciones de Chile Homepage, http://www.investigaciones.cl/ (accessed February 20, 2011). 56 CONACE Homepage http://www.conacedrogas.cl/portal
2000-01-01This ASTER images was acquired on May 2, 2000 over the North Patagonia Ice Sheet, Chile near latitude 47 degrees south, longitude 73 degrees west. The image covers 36 x 30 km. The false color composite displays vegetation in red. The image dramatically shows a single large glacier, covered with crevasses. A semi-circular terminal moraine indicates that the glacier was once more extensive than at present. ASTER data are being acquired over hundreds of glaciers worldwide to measure their changes over time. Since glaciers are sensitive indicators of warming or cooling, this program can provide global data set critical to understand climate change.This image is located at 46.5 degrees south latitude and 73.9 degrees west longitude. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud
2002-01-01A January 6, 2002 ASTER nighttime thermal infrared image of Chiliques volcano in Chile shows a hot spot in the summit crater and several others along the upper flanks of the edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24,2000 showed no thermal anomaly. Chiliques volcano was previously thought to be dormant. Rising to an elevation of 5778 m, Chiliques is a simple stratovolcano with a 500-m-diameter circular summit crater. This mountain is one of the most important high altitude ceremonial centers of the Incas. It is rarely visited due to its difficult accessibility. Climbing to the summit along Inca trails, numerous ruins are encountered; at the summit there are a series of constructions used for rituals. There is a beautiful lagoon in the crater that is almost always frozen.The daytime image was acquired on November 19, 2000 and was created by displaying ASTER bands 1,2 and 3 in blue, green and red. The nighttime image was acquired January 6, 2002, and is a color-coded display of a single thermal infrared band. The hottest areas are white, and colder areas are darker shades of red. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude.Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude.These images were acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A
Smith, M. G.; Sanhueza, P.; Schwarz, H. E.; Walker, A. R.
Monte Patria is the first Municipality in Chile to comply fully with Supreme Decree 686, the Chilean, environmentally-based legislation governing exterior lighting in Northern Chile - the "norma luminica". "Before" and "after" photographs of Monte Patria were published in last June's issue of "Physics Today", in the context of the global effort to control light pollution. Some photographs of other Chilean towns have been obtained for this poster and for display at the International Dark Sky Association's stand at this meeting. Highlights include detailed midnight and dawn panoramas taken by us during October, 2005 - the month in which the six-year "grace period" for all external lighting in northern Chile's astronomically-sensitive 2nd, 3rd and 4th Regions was supposed to come into full compliance. It is clear that significant progress is being made. The chief obstacle has been financial. Large-scale changeout of street lighting requires an outlay of many millions of dollars from cash-strapped municipalities. Chile's central government has moved in to provide financing at the 80-100/% level in many cases. Once Chile's congressional elections are over, we will be able to judge the political will to complete the changeover. Various large mining operations are currently engaged in major lighting changeovers; such changes are especially important in the various mines that are directly visible from existing major observatories in Northern Chile. The importance to astronomy is that full compliance with DS686 will, on average, extend the potential useful life of all the major optical observatories in Northern Chile by several decades. Funding for the Office for the Protection of the Quality of the Skies of Chile (OPCC) is provided by the Chilean National Environment Committee (CONAMA), NOAO, Gemini, ESO and the Las Campanas Observatory of the Carnegie Institute of Washington.
This piece begins with a brief discussion of the concepts leading to the social right to health protection. Special emphasis is placed on the principle of social cohesion, which has influenced social health protection in European countries. Chile's experience in this field from the 1990s to the present is described, as exemplified in three dimensions. In the first place, social security coverage is presented as a means to achieve universal (horizontal) coverage. A discussion follows on vertical coverage, where the author identifies health problems for which insured persons have guaranteed rights of access to medical care. This section describes available emergency care, primary health care, and the special plan for Universal Access to Explicit Guarantees (Acceso Universal de Garantías Explícitas de salud, or AUGE). Thirdly, the discussion covers the funding sources supporting the Chilean health care system: Government subsidies, contributions to social security, and out-of-pocket disbursements for private care. Chile's public health system has various special programs. One of them is catastrophic insurance, which covers 100% of the care needed for complex and very costly treatments. Older persons (over 65) have coverage for 100% of the cost of eyeglasses and hearing aids, and for 50% of the cost of home care. If life expectancy is an appropriate indicator of health system results, it is worth noting that Chile and the United States of America have both achieved a life expectancy of 77 years, even though Chile spends only 5.9% of its gross domestic product on health care, as compared to the 15% spent by the United States.
Alvarez Duarte, E; Denning, D W
The incidence and prevalence of fungal infections in Chile are unknown. Here, we have estimated the burden of serious fungal diseases from data obtained from clinical reports, WHO reports, Chilean census, OECD reports and comprehensive literature search available on PubMed and SciELO, among other scientific resources. Due the lack of official data about fungal diseases, frequencies were calculated based on the specific populations at risk. Recurrent vulvovaginal candidiasis (>4 episodes/year) is estimated to occur in 3108/100,000. Using a low international average rate of 5/100,000, we estimate 878 candidaemia cases and 132 patients with intra-abdominal candidiasis. Due to the low incidence of pulmonary tuberculosis (TB) in Chile, limited numbers of patients with chronic pulmonary aspergillosis are likely: a total of 1212, 25% following TB. Invasive aspergillosis is estimated to affect 296 patients following leukaemia therapy, transplantation and chronic obstructive pulmonary disease (COPD), 1.7/100,000. In addition, allergic bronchopulmonary aspergillosis (ABPA) and severe asthma with fungal sensitisation (SAFS) were estimated to be around 97.9/100,000 and 127/100,000 respectively, in 675,772 adult asthmatics and 1700 CF patients. Given a 38,000 human immunodeficiency virus (HIV) population, with around 2189 new cases of acquired immune deficiency syndrome (AIDS) annually, cryptococcal meningitis and Pneumocystis pneumonia are estimated at 0.12/100,000 and 4.3/100,000, respectively. In total, 325,000 (1.9%) people in Chile develop serious fungal infections annually. Respiratory fungal disease predominates in Chile; a national action plan for fungal disease is urgently needed, including epidemiological studies to validate the estimates.
Otzen, Tamara; Sanhueza, Antonio; Manterola, Carlos; Hetz, Monica; Melnik, Tamara
The aim of this study is to describe the trends of transport accident mortality in Chile from 2000 to 2012 by year, geographic distribution, gender, age group, and type of accident. Population-based study. Data for transport accident mortality in Chile between 2000 and 2012 were used. The crude and adjusted per region transport accident mortality rates were calculated per 100,000 inhabitants. The annual percentage change (APC) of the rates and relative risks (RR) were calculated. The average transport accident mortality rate (TAMR) in Chile (2000-2012) was 12.2. The rates were greater in men (19.7) than in women (4.8), with a RR of 4.1. The rates were higher in the country's southern zone (15.9), increasing in recent years in the southern zone, with a significant positive APC in the northern and central zones. The Maule region had the highest rate (21.1), although Coquimbo was the region with the most significant APC (2.2%). The highest rate (20.3) was verified in the 25-40 age group. The highest rate (14.3) was recorded in 2008. The most frequent type of accident was pedestrian. In general the APC trends of the rates are increasing significantly. This, added to rapid annual automotive growth, will only exacerbate mortality due to transport accidents.
Soto-Azat, Claudio; Peñafiel-Ricaurte, Alexandra; Price, Stephen J; Sallaberry-Pincheira, Nicole; García, María Pía; Alvarado-Rybak, Mario; Cunningham, Andrew A
Amphibians face an extinction crisis with no precedence. Two emerging infectious diseases, ranaviral disease caused by viruses within the genus Ranavirus and chytridiomycosis due to Batrachochytrium dendrobatidis (Bd), have been linked with amphibian mass mortalities and population declines in many regions of the globe. The African clawed frog (Xenopus laevis) has been indicated as a vector for the spread of these pathogens. Since the 1970s, this species has been invasive in central Chile. We collected X. laevis and dead native amphibians in Chile between 2011 and 2013. We conducted post-mortem examinations and molecular tests for Ranavirus and Bd. Eight of 187 individuals (4.3 %) tested positive for Ranavirus: seven X. laevis and a giant Chilean frog (Calyptocephallela gayi). All positive cases were from the original area of X. laevis invasion. Bd was found to be more prevalent (14.4 %) and widespread than Ranavirus, and all X. laevis Bd-positive animals presented low to moderate levels of infection. Sequencing of a partial Ranavirus gene revealed 100 % sequence identity with Frog Virus 3. This is the first report of Ranavirus in Chile, and these preliminary results are consistent with a role for X. laevis as an infection reservoir for both Ranavirus and Bd.
The outdoor experience's core element of connection to the earth is a central feature of an environmental-education project in Canl forest sanctuary (Chile). Developed to provide integrated environmental and adventure-education experiences to forest visitors, the project expanded to train local youth as ecotourism guides and native-tree nursery…
Lagos, Marcelo; Fritz, Hermann M.
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
Elacqua, Gregory; Alves, Fatima
Two themes connect Brazil and Chile: one is economic success; the other is social unrest. Protests rocked cities across Brazil in June 2013, and in Chile, recent student protests turned violent. Yet living conditions in both nations are better now than they've ever been. Successful economic and social reforms over the last two decades have led to…
15 1. Carabineros de Chile .............. 16 2. Policia de Investigaciones ........... 17 3. Direccion Nacional de Aduanas. ........ 17 4...institution is Investigaciones de Chile, the civilian police. It numbers close to 8,000 men. Its mission is crime investigation. Both institutions...currently depend on the Ministry of Defence and their scope is national. Carabineros and Investigaciones are the main agencies engaged in counter
Cifuentes-D, Marcela; Silva, Francisco; García, Patricia; Bello, Helia; Briceño, Isabel; Calvo-A, Mario; Labarca, Jaime
Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.
Giambiagi, Laura; Alvarez, Pamela; Spagnotto, Silvana
In order to understand the response of the stress field state to intrinsic processes during the construction of the Andes, such as thickening of the continental crust, lithospheric delamination, and/or thermal weakening, we investigate the stress field evolution of the arc region since the last 20 Myr, in the central Andes (22-26.5°S). The 43 reduced paleostress tensors derived from inversion of 682 fault slip data reveal a complex pattern of stress states during the last episode of orogenic construction and topographic uplift. We identify two geodynamic stages: the first stage corresponds to the construction of the Altiplano/Puna plateau and the second one to its gravitational collapse. Four stress states that have prevailed in the Altiplano/Puna plateau since middle Miocene times characterize the transition from one stage to the other. Along the study latitudes, a spatiotemporal change in stress state is clearly observed, which led to an understanding that a change in the stress field may be related not only to the boundary conditions but also to intrinsic factors associated with the construction of the Andean orogeny. Our results suggest that approximately at 13-10 Ma and approximately 8-5 Ma, in the southern Altiplano and northern Puna, and in the southern Puna, respectively, regional elevation and crustal thicknesses reached threshold values necessary to generate the orogenic collapse.
Rowe, P. M.; Cordero, R.; Warren, S. G.; Pankow, A.; Jorquera, J.; Schrempf, M.; Doherty, S. J.; Cabellero, M.; Carrasco, J. F.; Neshyba, S.
Black carbon (BC) and other light-absorbing impurities in snow absorb solar radiation and thus have the potential to accelerate glacial retreat and snowmelt. In Chile, glaciers and seasonal snow are important sources of water for irrigation and domestic uses. In July 2015 (Austral winter) we sampled snow in the western Andes in a north-south transect of Chile from 18 S to 34 S. Most of the sampled snow had fallen during a single synoptic event, during 11-13 July. The snow was melted and passed through 0.4 micrometer nuclepore filters. Preliminary estimates indicate that (1) the ratio of BC to dust in snow increases going south from Northern to Central Chile, and (2) in snow sampled during the two weeks following the snowstorm, the impurities were concentrated in the upper 5 cm of snow, indicating that the surface layer became polluted over time by dry deposition.
Leyva, Diana; Weiland, Christina; Barata, M; Yoshikawa, Hirokazu; Snow, Catherine; Treviño, Ernesto; Rolla, Andrea
Quality of teacher-child interactions is central to prekindergarten children's learning. In the United States, the quality of teacher-child interactions is commonly assessed using the teaching through interactions conceptual framework and an associ/ated observational tool, the Classroom Assessment Scoring System (CLASS). This study examined: (a) whether there was evidence supporting three distinctive domains of teacher-child interactions in Chile (construct validity) and (b) whether these domains predicted end-of-prekindergarten language, academic, and executive function skills in Chile (predictive validity). The sample consisted of 91 Chilean prekindergarten classrooms (1,868 four-year-old children). The findings support both construct and predictive validity of the teaching through interactions conceptual framework as assessed by the CLASS in Chile. Implications for cross-country comparison of quality of teacher-child interactions in prekindergarten classrooms are discussed.
Vásquez, Marcela; Maldonado, Mónica; Tagle, Federico; León, Sergio; Soto, Alejandra; Mena, Aaron; Toro, Carla
A review of the management of blood supply and its administration during disasters was conducted based on the experience of several events that occurred primarily from 2000-2010, particularly the earthquake that measured 8.8 on the Richter scale that struck central and southern Chile on 27 February 2010. The objective was to provide information that could be useful in improving response plans and strategies during potential future disasters. The descriptive information on response procedures was obtained from interviews, internal reports, and the computer database from the Maule regional blood production center. The results lead to the conclusion that to respond efficiently and effectively to the need for blood in the immediate wake of a disaster it is essential to have both a centralized management system that facilitates the supply and administration of blood and volunteers with competence in health that are willing to swiftly arrive during these events. A change in the profile of blood donors during such emergencies was also observed. In Chile, for example, during the two weeks after the earthquake, the ratio of male/female donors was reversed. There was 61.1% participation by women, whereas in the week before the event women accounted for only 37%.
As announced in an earlier Press Release (PR 08/94 of 6 May 1994), a high-ranking ESO delegation visited Santiago de Chile during the week of 24 - 28 May 1994 to discuss various important matters of mutual interest with the Chilean Government. It consisted of Dr. Peter Creola (President of ESO Council), Dr. Catherine Cesarsky (Vice-President of ESO Council), Dr. Henrik Grage (Former Vice-President of ESO Council) and Professor Riccardo Giacconi (ESO Director General), the latter accompanied by his advisers. THE SUPPLEMENTARY TREATY BETWEEN CHILE AND ESO Following a meeting with the ambassadors to Chile of the eight ESO member countries, the ESO delegation was received by the Chilean Minister of Foreign Affairs, Mr. Carlos Figueroa, and members of his staff. The ESO delegation was pleased to receive assurances that the present Chilean Government, like its predecessors, will continue to honour all contractual agreements, in particular the privileges and immunities of this Organisation, which were laid down in the Treaty between ESO and Chile that was signed by the parties in 1963 and ratified the following year. The discussions covered some aspects of the proposed Supplementary Treaty which has been under preparation during the past year. This included in particular the desire of the Chilean side to further increase the percentage of guaranteed time for Chilean astronomers at the future ESO Very Large Telescope (VLT) and also the rules governing the installation by ESO member countries of additional telescopes at the ESO observatories in Chile. ESO invited a Chilean delegation to visit the ESO Headquarters in Garching (Germany) later this year for the final adjustment of the text of the Supplementary Treaty, after which it should be possible to proceed rapidly with the signing and ratification by the Chilean Parliament and the ESO Council. THE SITUATION AROUND PARANAL The ESO delegation expressed its deep concern to the Chilean Government about the continuing legal
[Joint Press Release by the Government of the Republic of Chile and the European Southern Observatory. The text is issued simultaneously in Santiago de Chile (in Spanish) and at the ESO Headquarters in Garching (in English).] Today, Tuesday, 18 April 1995, at the ESO Headquarters in Garching (Germany), Mr. Roberto Cifuentes, Plenipotentiary Ambassador representing the Government of the Republic of Chile, and the Director General of the European Southern Observatory, Professor Riccardo Giacconi, have signed a Supplementary, Interpretative and Amending Agreement to the Convention of 6 November 1963 which governs the relations between Chile and this International Organisation. This Agreement which in practice signifies a widening and strengthening of the cooperative relations between the Organisation and the Chilean scientific community will hereafter be submitted for ratification by the National Congress of the Republic of Chile (the Parliament) and by the ESO Council. According to the Agreement signed today, Chilean astronomers will have privileged access within up to 10 percent observing time on all present and future ESO telescopes in Chile. Moreover, ESO accepts to incorporate into its labour regulations for Chilean personnel concepts like freedom of association and collective bargaining. This signing of the Supplementary, Interpretative and Amending Agreement to the original Convention of 1963 follows after months of constructive dialogue between the parties. It constitutes an important step towards a solution of some of the pending points on the current agenda for discussions between the Government of Chile and ESO. Among the issues still pending, ESO has informed the Government of Chile that respect for its immunities by the Chilean State is of vital importance for the continuation of the construction of the world's largest telescope at Paranal, as well as the continued presence of the Organisation in Chile. The Chilean Government, on its side, and concerning
Langdon, M C; Gazmuri, C; Venegas, L
The leading health problems of children and adolescents in Chile is reviewed. The Chilean educational system and how the system addresses its principal health problems are described. A school health program is described as well as other educational programs designed and developed by nongovernmental institutions which have a smaller coverage. Current research studies regarding growth and development, child morbidity, nutritional level, and mental health studies are reviewed. In addition, principal challenges that include developing more efficient ways of referring children, enriching the curriculum and teacher training, assigning school hours for health teachers, and enlarging coverage of the health care evaluation programs are outlined. Of special importance is developing prevention programs for parents and children using school and community leaders to prevent health problems in areas such as human sexuality education, decision-making, social abilities, and alcohol and drug abuse. Main efforts should be directed toward low-income families and children to improve life conditions.
This paper describes a village application in Chile. The objective was to demonstrate the technical, economic and institutional viability of renewable energy for rural electrification, as well as to allow local partners to gain experience with hybrid/renewable technology, resource assessment, system siting and operation. A micro-grid system is viewed as a small village system, up to 1200 kWh/day load with a 50 kW peak load. It can consist of components of wind, photovoltaic, batteries, and conventional generators. It is usually associated with a single generator source, and uses batteries to cover light day time loads. This paper looks at the experiences learned from this project with regard to all of the facets of planning and installing this project.
Guzmán, Jonathan A; D'Elía, Guillermo; Ortiz, Juan Carlos
We studied the geographic variation of skulls of Lycalopex culpaeus using qualitative and quantative analyses. The sampling area covered Chile, from its northern portion, to Tierra del Fuego and the neighbouring Hoste Island, as well as part of Argentina. Five subespecies are currently recognized from this large area. We found two morphotypes that are segregated geographically. Both groups mostly differ by morphometric attributes, followed by qualitative features. Specimens from northern Chile (Tarapacá and Antofagasta) have small skulls, short rostrum, a liriform sagital zone, and lack the interparietal crest. The second group is formed by specimens from north-western and central Argentina, central-south Chile, Patagonia, and the austral islands of Tierra del Fuego and Hoste. This group presents a strong sagital crest, large rostrum, and a large skull. Our results agree with observed patterns of mitochondrial DNA variation. We propose to retain the name L. c. andinus for the populations of northern Chile and to synonymize L. c. magellanicus, L. c. lycoides, and L. c. smithersi under L. c. culpaeus.
Mourgues, Francisco Amaro
Preliminary results about the Lower Cretaceous ammonite biostratigraphy of northern Chile reveal eight fossiliferous levels: Lower-Upper Valanginian neocomitid and olcostephanid faunas in the Punta del Cobre and Abundancia Formations and Upper Hauterivian-Barremian crioceratid in the Nantoco, Totoralillo, and Pabellón Formations. The faunal affinities with the Neuquén are strong during the Valanginian and Hauterivian. In contrast, during the Barremian and Aptian, the ammonites show affinities with Austral, California, and Tethys basinal faunas. The Lower Valanginian-lower Upper Aptian series in northern Chile comprises two sedimentary cycles separated by a regressive pulse of Upper Hauterivian-Lower Barremian age. This pulse may be equivalent to the regression that ended the Early Cretaceous marine cycle in central Chile and central west Argentina, where the second marine sedimentary cycle observed in northern Chile is not represented.
García-Cedillo, Ismael; Romero-Contreras, Silvia; Ramos-Abadie, Liliana
This paper discusses the background, current situation and challenges of educational integration and inclusive education in Mexico and Chile. These countries obtained similar low results on the academic achievement of their students (Mexico last and Chile second last) among OECD countries; and above average scores, among Latin-American countries.…
O'Ryan, Miguel; Valenzuela, María Teresa
Molecular, clinical and epidemiological studies have established beyond doubt that human papiloma viruses (HPV) cause cervical cancer. The virus is also associated with genital warts and other less common cancers in oropharynx, vulva, vagina and penis. Worldwide, VPH genotypes 16 and 18 are the most common high risk genotypes, detected in near 70% of women with cervical cancer. The discovery of a cause-effect relationship between several carcinogenic microorganisms and cancer open avenues for new diagnostic, treatment and prevention strategies. In this issue of Revista Médica de Chile, two papers on HPV are presented. Guzman and colleagues demonstrate that HPV can be detected in 66% to 77% of healthy male adolescents bypolymerase chain reaction and that positivity depends on the site of the penis that is sampled. These results support the role of male to female transmission of high risk HPVs in Chile and should lead to even more active educational campaigns. The second paper provides recommendations for HPV vaccine use in Chile, generated by the Immunization Advisory Committee of the Chilean Infectious Disease Society. To issue these recommendations, the Committee analyzes the epidemiological information available on HPV infection and cervical cancer in Chile, vaccine safety and effectiveness data, and describes cost-effectiveness studies. Taking into account that universal vaccination is controversial, the Committee favors vaccine use in Chile and it's incorporation into a national program. However, there is an indication that the country requires the implementation of an integrated surveillance approach including cross matching of data obtained from HPV genotype surveillance, monitoring of vaccination coverage, and surveillance of cervical cancer. The final decision of universal vaccine use in Chile should be based on a through analysis of information.ev Mid Chile
Plominsky, Alvaro M; Delherbe, Nathalie; Ugalde, Juan A; Allen, Eric E; Blanchet, Marine; Ikeda, Priscila; Santibañez, Francisco; Hanselmann, Kurt; Ulloa, Osvaldo; De la Iglesia, Rodrigo; von Dassow, Peter; Astorga, Marcia; Gálvez, María Jesús; González, María Lorena; Henríquez-Castillo, Carlos; Vaulot, Daniel; Lopes do Santos, Adriana; van den Engh, Gerrit; Gimpel, Carla; Bertoglio, Florencia; Delgado, Yolaine; Docmac, Felipe; Elizondo-Patrone, Claudia; Narváez, Silvia; Sorroche, Fernando; Rojas-Herrera, Marcelo; Trefault, Nicole
Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns that are arranged as interconnected ponds with increasing salt concentrations. Here, we report the metagenome of the 3.0- to 0.2-µm fraction of the microbial community present in a crystallizer pond with 34% salinity.
Plominsky, Alvaro M.; Delherbe, Nathalie; Ugalde, Juan A.; Allen, Eric E.; Blanchet, Marine; Ikeda, Priscila; Santibañez, Francisco; Hanselmann, Kurt; Ulloa, Osvaldo; De la Iglesia, Rodrigo; von Dassow, Peter; Astorga, Marcia; Gálvez, María Jesús; González, María Lorena; Henríquez-Castillo, Carlos; Vaulot, Daniel; Lopes do Santos, Adriana; van den Engh, Gerrit; Gimpel, Carla; Bertoglio, Florencia; Delgado, Yolaine; Docmac, Felipe; Elizondo-Patrone, Claudia; Narváez, Silvia; Sorroche, Fernando; Rojas-Herrera, Marcelo
Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns that are arranged as interconnected ponds with increasing salt concentrations. Here, we report the metagenome of the 3.0- to 0.2-µm fraction of the microbial community present in a crystallizer pond with 34% salinity. PMID:25395641
Schaub, G A; Schottelius, J
Examination of 54 Triatoma infestans from a village near the European Southern Observatory La Silla in Chile and of 9 Triatoma spinolai from the territory of the observatory showed that 10 T. infestans were infected with trypanosomatids. Mice were infected with in vitro cultures initiated with five different trypanosomatid isolates and treated with the immunosuppressive drug cyclophosphamide to increase the parasitemia of the flagellates. Evidence of the presence of T. cruzi was provided by a comparative biometrical analysis of blood trypomastigotes and the occurrence of intracellular amastigotes. Three methods for further identification were used: examination of kDNA ultrastructure, disc electrophoresis of soluble proteins and the Aaptos papillata II lectin induced agglutination. We obtained the following results for all isolates: (1) presence of a central band of the kDNA; (2) T. cruzi specific double bands of the protein patterns; (3) positive reaction with Aaptos papillata II. No differences between the five isolates from Chile and T. cruzi or T. cruzi-like strains from other countries could be observed. Based on these results an infection of the bugs with T. rangeli and T. conorhini could be excluded.
Schöning, Meike; Bandel, Klaus
Silicified woods of 10 dicotyledonous tree families of probably Miocene age from the Arauco Peninsula, central Chile are described and classified according to their anatomy. The diversity is surprisingly high, in that of the 19 samples analyzed, virtually every one could belong to a different species of tree or shrub. Almost all species document a damp climate, and most have related species living in the central zone of modern Chile. The samples were collected in a narrow zone on Punta El Fraile, west of the town of Arauco. The following families are based on woods from the Arauco Peninsula: Anacardiaceae, Boraginaceae, Euphorbiaceae, Fagaceae, Lauraceae, Leguminosae, Monimiaceae, the first report of fossil Myristicaceae, Myrtaceae, and Proteaceae. Their diagenetic history is connected to tuffaceous material and calcareous concretions.
Campos-Soto, Ricardo; Ortiz, Sylvia; Cordova, Ivan; Bruneau, Nicole; Botto-Mahan, Carezza; Solari, Aldo
Chagas disease, which ranks among the world's most neglected diseases, is a chronic, systemic, parasitic infection caused by the protozoan Trypanosoma cruzi. Mepraia species are the wild vectors of this parasite in Chile. Host-parasite interactions can occur at several levels, such as co-speciation and ecological host fitting, among others. Thus, we are exploring the interactions between T. cruzi circulating in naturally infected Mepraia species in all areas endemic of Chile. We evaluated T. cruzi infection rates of 27 different haplotypes of the wild Mepraia species and identified their parasite genotypes using minicircle PCR amplification and hybridization tests with genotype-specific DNA probes. Infection rates were lower in northern Chile where Mepraia gajardoi circulates (10-35%); in central Chile, Mepraia spinolai is most abundant, and infection rates varied in space and time (0-55%). T. cruzi discrete typing units (DTUs) TcI, TcII, TcV, and Tc VI were detected. Mixed infections with two or more DTUs are frequently found in highly infected insects. T. cruzi DTUs have distinct, but not exclusive, ecological and epidemiological associations with their hosts. T. cruzi infection rates of M. spinolai were higher than in M. gajardoi, but the presence of mixed infection with more than one T. cruzi DTU was the same. The same T. cruzi DTUs (TcI, TcII, TcV, and TcVI) were found circulating in both vector species, even though TcI was not equally distributed. These results suggest that T. cruzi DTUs are not associated with any of the two genetically related vector species nor with the geographic area. The T. cruzi vectors interactions are discussed in terms of old and recent events. By exploring T. cruzi DTUs present in Mepraia haplotypes and species from northern to central Chile, we open the analysis on these invertebrate host-parasite interactions.
The Chilean Red Cross Society and the family planning association--APROFA, International Planned Parenthood Federation's affiliate, are joining forces to help prevent the spread of the acquired immunodeficiency syndrome (AIDS) and human immunodeficiency virus (HIV) infection. APROFA established a working group to study the knowledge, attitudes, and sexual behavior of students at the National Training Institute, INACAP. 7000 students were sampled in 11 Chilean cities. The study found that 36% of the females, and 77% of males were sexually active before the age of 20. Nearly 1/2 of the women and 1/5 of the men did not know that condoms could protect them against sexually transmitted diseases (STDs) and pregnancy. APROFA designed a program to increase students knowledge of AIDS, reduce promiscuity and increase knowledge of and use of condoms. In October, 1988 an educational package distributed, consisting of a training manual, slides, educational booklets, a poster, and a video of 3 films. It has proved so successful that APROFA has adapted it for community groups, educational institutions, and its youth program. APROFA/Red Cross nurses and Red Cross volunteers have participated in workshops and training with the package. The Red Cross has organized AIDS-related activities in Chile since 1986, including education campaigns, information for blood donors, and a telephone hotline to provide AIDS counseling. Goals are to target more poor areas and groups outside of society's mainstream in the next year for sex education and information on STDs.
The first Chair of Microbiology in Chile was created in the School of Medicine of the Cañadilla at the University of Chile in 1892. Dr. Alejandro del Río Soto Aguilar was its first Professor. For almost three decades it was the only educational center for microbiologists in Chile. Among them were the first Professors of the new School of Medicine of the Catholic University of Chile and of the University of Concepción.
Fraude Electoral Designada por la Facultad de Derecho de la Pontifica Universidad de Chile," in Libro Blanco del Cambio de Gobierno de Chile, Editorial...armed forces. Argentine police arrested Edgardo Enriquez, whom they deported to Chile. Humberto Sotomayor apparently left the movement, leaving Andres...often either deport them or sentence them to jail or internal -14- exile. The government seems able to capture the miristas who infiltrate into Chile
Slater, William F.
Presents an annotated bibliography of materials on the history of Chile from the 1500s to the twentieth century. The bibliography includes works from the United States, England, and Chile on a variety of topics, including the colonial period, Pre-Columbian Chile, Indian life, culture, political structure, the impact of Spanish Imperialism, land…
The following ideas are widely accepted in Chile with respect to scientific activity: is carried out mainly in universities and science is considered a naturally university activity, that was developed in a period of more than 150 years by isolated individual efforts, c) it was transformed into an institutionalized activity at the universities after the university reform movement at the end of the 1960 decade, d) the activity is finally institutionalized in the country with the creation of the “Comisión Nacional de Investigatión Científica y Tecnológica, CONICYT (National Commission for Scientific and Technological Research) in 1967. This work presents preliminary findings showing that there are other institutional initiatives, different to the efforts from universities and directly dependent of the Chilean Government, in order to produce science and technology in Chile. This governmental initiatives start at the beginning of the Republic of Chile circa of 1810.
The SPOC Team; Krawcyzk, C.
The southern central Chilean margin at the site of the largest historically recorded earthquake in the Valdivia region, in 1960 (Mw = 9.5), is part of the 5000-km-long active subduction system whose geodynamic evolution is controversially debated and poorly understood. Covering the area between 36° and 40°S, the oceanic crust is segmented by prominent fracture zones. The offshore forearc and its onshore continuation show a complex image with segments of varying geophysical character, and several fault systems active during the past 24 m.y.In autumn 2001, the project SPOC was organized to study the Subduction Processes Off Chile, with a focus on the seismogenic coupling zone and the forearc. The acquired seismic data crossing the Chilean subduction system were gathered in a combined offshore-onshore survey and provide new insights into the lithospheric structure and evolution of active margins with insignificant frontal accretion.
MIGRA Group; Götze, H.-J.
Between 1993 and 1995 a group of scientists from Chile, Argentina, and Germany incorporated some 2000 new gravity observations into a database that covers a remote region of the Central Andes in northern Chile and northwestern Argentina (between 64°-71°W and 20°-29°S). The database can be used to study the structure and evolution of the Andes. About 14,000 gravity values are included in the database, including older, reprocessed data. Researchers at universities or governmental agencies are welcome to use the data for noncommercial purposes.
Humanitarian Affairs, “Chile Earthquake: Situation Report #2,” March 1, 2010; Gobierno de Chile, “Situación terremoto zona centro sur (Actualiza...Earthquake: Situation Report #2,” March 1, 2010; Gobierno de Chile, “Situación terremoto zona centro sur (Actualiza reporte),” March 1, 2010...Catástrofe desde terremoto de 1985,” El Mercurio (Chile), March 1, 2010; “Amplían toque de queda en zonas más afectadas por terremoto en Chile
EPA delivered a two-day workshop in Chile, on public participation. The course intended to enable students to increase the level of public impact through the levels of public participation, found on EPA’s Public Participation Guide.
EPA delivered a two-day workshop in Santiago, Chile, on public participation. The course intended to enable students to increase the level of public impact through the levels of public participation, found on EPA’s Public Participation Guide.
Starke, Allan; Cardemil, José M.; Escobar, Rodrigo; Colle, Sergio
The electricity systems in Chile are characterized by a variable hourly demand in the central grid and an almost constant demand in the northern grid, which require different operation strategies for solar power plants depending on their location. Hybridizing a CSP plant with a PV plant can increase the whole plant capacity factor by allowing thermal energy to be stored while the PV plant is in production and thus help to achieve a fully dispatchable solar electricity production system. A thermal and economic analysis of hybrid CSP+PV plants is conducted considering a range of plant capacities based on a parabolic trough plant with the addition of a PV plant for the environmental conditions of Crucero in Northern Chile, which is a hotspot for solar energy development in the country. The study considers a parametric analysis and optimization of the storage and power block sizes for the CSP plant in terms of the levelized cost of energy (LCOE) for varying PV plant nominal capacity. The annual production of the plants are calculated by using the Transient System Simulation program (TRNSYS), which uses a new component library developed for that purpose. The results show good agreement with other software packages as well as with actual data from currently operating CSP plants. The adopted approach helps the proper assessment of the integration of different technologies, since it uses the well-kwon modular structure of the TRNSYS. Regarding the potential for the hybrid solar-solar plants in the Atacama Desert, the high level of irradiation available in Chile can provide a competitive electricity cost, allowing to investors the access to PPA contracts with mining companies in northern Chile. Additionally, the optimization analysis shows that the northern regions of Chile present an outstanding potential for the deployment of such projects.
Reyes, Miguel T.
This paper begins with a discussion of the origins of Chilean television, including its channels, programs, and transmission times, and how education for television has arisen in Chile as a defense against its influence. The initial concern of sociologists' about this influence and later development of ideas and programs by a number of…
Harvest mechanization as a system requires modifying or creating new components including cultivars, production practices, and harvest, transportation and processing plant machinery. New Mexican chile is one of the last segments of the pepper industry to still rely on hand labor. This paper reports ...
assistant professor at the Pontifi cia Universidad Católica de Chile School of Medicine. Her research interests include tuberculosis diagnosis and...1596–9. doi:10.1093/molbev/msm092 13. Kikuchi Y, Fukatsu T. Rickettsia infection in natural leech popu- lations. Microb Ecol. 2005;49:265–71. doi
González-Escalona, Narjol; Cachicas, Viviana; Acevedo, Claudia; Rioseco, María L.; Vergara, Juan A.; Cabello, Felipe; Romero, Jaime
Analysis of clinical isolates of Vibrio parahaemolyticus from outbreaks in Chile in the cities of Puerto Montt in 2004 and in Antofagasta in 1998 indicated that 23 of 24 isolates from Puerto Montt and 19 of 20 from Antofagasta belonged to the pandemic clonal complex that emerged in Southeast Asia in 1996. PMID:15705337
González-Escalona, Narjol; Cachicas, Viviana; Acevedo, Claudia; Rioseco, María L; Vergara, Juan A; Cabello, Felipe; Romero, Jaime; Espejo, Romilio T
Analysis of clinical isolates of Vibrio parahaemolyticus from outbreaks in Chile in the cities of Puerto Montt in 2004 and Antofagasta in 1998 indicated that 23 of 24 isolates from Puerto Montt and 19 of 20 from Antofagasta belonged to the pandemic clonal complex that emerged in Southeast Asia in 1996.
In chronicles or in the historiography of the Colony in Chile there are few references about epidemics different to smallpox; like typhus, typhoid fever, dysentery, etc. Almost all, fast spreading in the country and some with high lethality, which led to overflowing the capacity of hospitals in the Chilean colonial period.
Chacón, F; Bacigalupo, A; Quiroga, J F; Ferreira, A; Cattan, P E; Ramírez-Toloza, G
American trypanosomiasis is a chronic disease transmitted mainly by vectors. The hematophagous triatomine vectors transmit Trypanosoma cruzi to a wide variety of mammals, which usually are their food source. This study determined the feeding profile of Mepraia spinolai, a sylvatic triatomine vector, present in endemic areas of Chile. Vectors were captured in the north-central area of Chile. Samples of intestinal contents were analyzed by an Enzyme-linked immunosorbent assay (ELISA) that identifies and discriminates the presence of serum antigens from Homo sapiens and nine animal species (Canis familiaris, Felis catus, Capra hircus, Mus musculus, Gallus gallus, Octodon degus, Thylamys elegans, Phyllotis darwini and Oryctolagus cuniculus). Our data indicate the most frequent feeding source in this area was P. darwini, followed by O. degus, O. cuniculus, M. musculus, G. gallus, T. elegans, C. familiaris, F. catus and C. hircus. Mixed food sources were also identified.
Evenstar, Laura; Mather, Anne; Stuart, Finlay; Cooper, Frances; Sparks, Steve
Supergene enrichment of porphyry copper deposits in the central Andes is thought to be closely correlated with periods of relatively humid climate and the formation of regionally extensive paleosurfaces (e.g. Mortimer, C. 1973) . In northern Chile, two such paleosurfaces have been proposed: the ca. 23 Ma Tarapaca paleosurface within the Coastal Cordillera, and the ca. 10 Ma Pacific paleosurface within the Longitudinal Valley. The Pacific paleosurface is regarded as a single stratigraphic horizon that formed due to either a marked increase in the aridity of the area (Galli-Oliver 1967), regional surface uplift that created a change in the locus of deposition (e.g. Mortimer and Rendic 1975), or a combination of the two. The formation of this surface has been associated with the timing of supergene enrichment throughout the northern Chile and southern Peru (Alpers and Brimhall 1988). Multispectral satellite mapping of the Pacific paleosurface in northern Chile using Landsat, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Digital Elevation Model (DEM) imagery, combined with seismic data (Jordan et al. 2010) indicates that the Pacific paleosurface is not a single chronostratigraphic surface, as previously thought, but an amalgamation of surfaces that have both an erosional and depositional history. New in situ cosmogenic exposure dating of alluvial boulders on the paleosurface is combined with previous data (Dunai et al. 2005, Kober et al. 2007 and Evenstar et al., 2009) giving ages ranging from ca. 23 Ma to <1 Ma, supporting a multiphase and much more continuous history. By combining these apparent exposure ages with regional geomorphology, underlying sedimentology, and seismic sections, the geomorphic evolution of the Longitudinal Valley can be constrained. The results show a complex interplay between uplift within the Coastal Cordillera and Precordillera in the south and a distinct change in depositional pattern towards the north. The
Cianelli, Rosina; Ferrer, Lilian; Norr, Kathleen F.; McCreary, Linda; Irarrázabal, Lisette; Bernales, Margarita; Miner, Sarah
Purpose When healthcare workers have stigmatizing attitudes toward people living with HIV it may lead to discriminatory behavior that interferes with prevention, treatment, and care. This research examined the HIV-related stigmatizing attitudes reported by health workers in Santiago, Chile. Methods The study used focus group data from the first phase of a larger study to develop and test a HIV prevention intervention for Chilean health workers. Ten focus groups were conducted with Health workers in two communities in Santiago, Chile. Content analysis was used to analyze the data. Results Two central themes emerged: Societal stigma and discrimination towards people living with HIV and healthcare system’s policies related to HIV. Both inaccurate fears of transmission among the general public and Chilean Health workers and societal prejudices against homosexuals contributed to stigmatization and discrimination. Conclusions Health workers did not recognize their own stigmatizing attitudes or discriminatory behaviors, but their discussion indicated that these behaviors and attitudes did exist. Healthcare system issues identified included problems with confidentiality due to the desire to inform other health workers about client HIV status. Health workers must be sensitized to the current stigmatization and misinformation associated with HIV and its negative impacts on persons living with HIV and the general community. Implications All clinical and non-clinical workers at community clinics need mandatory education for HIV prevention that focuses on changing attitudes as well as sharing knowledge. Also, the Chilean law protecting people living with HIV and the confidentiality of their medical care needs to be publicized, along with guidelines for its enactment in clinics and other health facilities. PMID:21687824
Zambrano, Francisco; Wardlow, Brian; Tadesse, Tsegaye
Precipitation is a key parameter for the study of climate change and variability and the detection and monitoring of natural disaster such as drought. Precipitation datasets that accurately capture the amount and spatial variability of rainfall is critical for drought monitoring and a wide range of other climate applications. This is challenging in many parts of the world, which often have a limited number of weather stations and/or historical data records. Satellite-derived precipitation products offer a viable alternative with several remotely sensed precipitation datasets now available with long historical data records (+30 years), which include the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR) datasets. This study presents a comparative analysis of three historical satellite-based precipitation datasets that include Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B43 version 7 (1998-2015), PERSIANN-CDR (1983-2015) and CHIRPS 2.0 (1981-2015) over Chile to assess their performance across the country and evaluate their applicability for agricultural drought evaluation when used in the calculation of commonly used drought indicator as the Standardized Precipitation Index (SPI). In this analysis, 278 weather stations of in-situ rainfall measurements across Chile were initially compared to the satellite-based precipitation estimates. The study area (Chile) was divided into five latitudinal zones: North, North-Central, Central, South-Central and South to determine if there were a regional difference among these satellite-based estimates. Nine statistics were used to evaluate the performance of satellite products to estimate the amount and spatial distribution of historical rainfall across Chile. Hierarchical cluster analysis, k-means and singular value decomposition were used to
Zambrano, Francisco; Wardlow, Brian; Tadesse, Tsegaye; Lillo-Saavedra, Mario; Lagos, Octavio
Precipitation is a key parameter for the study of climate change and variability and the detection and monitoring of natural disaster such as drought. Precipitation datasets that accurately capture the amount and spatial variability of rainfall is critical for drought monitoring and a wide range of other climate applications. This is challenging in many parts of the world, which often have a limited number of weather stations and/or historical data records. Satellite-derived precipitation products offer a viable alternative with several remotely sensed precipitation datasets now available with long historical data records (+30years), which include the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR) datasets. This study presents a comparative analysis of three historical satellite-based precipitation datasets that include Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B43 version 7 (1998-2015), PERSIANN-CDR (1983-2015) and CHIRPS 2.0 (1981-2015) over Chile to assess their performance across the country and for the case of the two long-term products the applicability for agricultural drought were evaluated when used in the calculation of commonly used drought indicator as the Standardized Precipitation Index (SPI). In this analysis, 278 weather stations of in situ rainfall measurements across Chile were initially compared to the satellite data. The study area (Chile) was divided into five latitudinal zones: North, North-Central, Central, South-Central and South to determine if there were a regional difference among these satellite products, and nine statistics were used to evaluate their performance to estimate the amount and spatial distribution of historical rainfall across Chile. Hierarchical cluster analysis, k-means and singular value decomposition were used to analyze
Tuberculosis (TB) remains a major global and national problem. In Chile the incidence rate has remained at 13 per 100,000 inhabitants for several years without tendency to the expected decline that would allow their elimination by 2020. As a low prevalence country, TB cases have been concentrated in risk groups, reaching 33% in 2013, and this proportion increases as younger people are analyzed. The main risk groups in Chile are HIV co-infection, foreigners and population of prisons. By 2013, the proportion of cases for these three groups was 8.7%, 8.4% and 3.9% respectively, and these percentages vary significantly when regional situation is analyzed. In addition, many of these patients have more than one risk factor, demons-rating the existence of clusters more vulnerable to TB.
The Chilean Academy of Medicine published a "Report on the Current Status of Medical Education in Chile". This report reviews the history of medical education in this country and its close relationship with the Health Care System, public and private; highlights the main changes that took place during the last 25 years in superior and medical education; provides information on the 26 currently existing Medical Schools; refers to the availability of medical doctors and specialists; discusses the mechanisms that control the quality of institutions involved and their programs; and summarizes the results of the Annual National Medical Examination. The members of the Committee on Superior Education of the Academy provided a critical analysis of medical education in Chile and recommendations on how to improve it.
Caglevic, Christian; Silva, Shirley; Mahave, Mauricio; Rolfo, Christian; Gallardo, Jorge
Gastric cancer is a neoplasm with a high incidence and mortality rate in Chile where more than 3000 people die every year from this type of cancer. This study shows the clinical and epidemiological considerations of this disease, information about translational research on this pathology in Chile, the contribution of Chilean doctors to the development of gastric cancer management awareness and the general situation of gastric cancer in Chile. PMID:28105078
Healthcare represents a key area in the public agenda. In the case of Chile, this central part of citizen demands has emerged with an increasing criticism of the health system, its actors and institutions, while a major democratic and legitimacy crisis in Chilean society unfolds. The starting point of this analysis is the link between the critical and widespread societal dissatisfaction with the legitimacy crisis in the health sector. There is an interdependence and parallelism between these two different aspects of the crisis. The analysis is built around the dimensions of trust and legitimacy as a potential driver of the conflict, taking as an analytical framework the socio-political matrix. Conceptual elements around the ideas of trust and legitimacy in public policies are reviewed. This article focuses on recent situations surrounding the dynamics of the Chilean health system such as the rise of the Instituciones de Salud Previsional (ISAPRE) and the market-driven health system, the failed health care reform of the last decade, conflicts of interest in the formulation of public policies, loss of legitimacy of healthcare authorities, and the role of the health professionals in this process. Finally, a discussion arises seeking to regain public trust as a central issue for the future development and sustainability of health policies.
Ebaugh, Cameron D.
Chile is a republic 2,630 miles long, extending along the western coast of South America from Peru to the southernmost tip of the continent. In width it averages about 110 miles, with snow-capped, volcano-studded Andes in the East, a low coastal range along the Pacific and a string of valleys and plains in between. It is estimated that 5,000…
Libro Blanco del Cambio de Gobierno en Chile. Santiago: Editorial Lord 23 Cochrane, 1973, pp. 103-108. See also Page 8 for a photograph of Allende...Rothenberg, Soviet Penetration, p. 144. 18. The letter in Castro’s handwriting is published in the Libro Blanco, p. 101- 102. In the UN debates after the...a Via Chilena a la Via Insurreccional, Santiago: Editorial del Pacifico, 1974, pp. 296ff. 19. Libro Blanco includes (pp. 192 and 197) what appear to
him to return. During his absence Chile was ruled by a junta lead by General Carlos Ibanez del Campo . Welcomed back in March 1925, Alessandri kept...of the Radicals, a previous agreement be made that the President come from the parties which had formed the Popular Action Front (Frente de Accion ...dictatorship of Colonel (later General) Carlos Ibanez del Campo in 1931-32. The first two were the product of divisions within the political community; the last
Chile's tuberculosis morbidity notification statistics suggest that there has been a 3% average annual decrease in tuberculosis cases in the last 5 years (1978-82). In addition, over the period 1974-83, there was a 50% decline in the number of deaths from tuberculosis. In 1982, there were 6941 recorded cases of tuberculosis in Chile, only 6.5% of which involved children under 15 years of age; in that same year, there were 984 deaths from tuberculosis, 14.4% of which occurred in children. The majority of cases reported (78%) involve pulmonary tuberculosis. Over 90% of children under 15 years of age are covered by Bacille Calmette-Guerin (BCG) vaccination. This was achieved by immunizing 91% of all newborns, 83% of children in their first year of school, and 98% of those in their final year. Laboratories capable of case-finding now cover 95% of Chile's total area. Since 1975, an average of 47 bacilloscopies have been performed per 1000 consultations. Abandonment of treatment has been reduced to 12% and fewer than 20% of cases require hospitalization. Finally, the introduction of shortened rifampicin treatment has reduced the case-fatality rate from 6% to 3%.
In 1994, Chile had 15,451 active physicians (less than 70 years old) for a population of 14,027,344 with a ratio of 1 physician per 908 inhabitants, a satisfactory figure compared to other countries of similar socio-economical development. Ratios of 1:880 and 1:843 are projected for 1999 and 2004 respectively. The annual rate of physician's population growth (2.2%), that is superior to the general population's growth rate (1.6%), will increase to about 2.5% per annum in 2001 as a consequence of the creation of three new medical schools. However, the distribution of physicians along the country is unsatisfactory. While the capital (Metropolitan Region) has a ratio of 1 physician per 629 inhabitants, the figure for the Region of Maule is 1:2,113. Only two of ten regions, excepting the capital, have a ratio lower than 1:1,000. Sixty percent of physicians live in Santiago while only 40% of the general population does so, illustrating their high concentration. Median ratio in Chile, that better reflects the reality than the mean, is 1:1,280. The heterogeneous distribution of physicians in Chile is a sign of social inequity that must be corrected. In a free society a better physician distribution is achieved with economical and professional incentives given by health institutions.
Fuentes-Castillo, Danny; Cicchino, Armando; Mironov, Sergey; Moreno, Lucila; Landaeta-Aqueveque, Carlos; Barrientos, Carlos; González-Acuña, Daniel
Despite being a bird with a broad and extensive distribution in Chile, the black-chinned siskin, Spinus barbatus Molina, 1782 is not well studied in relation to its parasites. This paper aims to describe the ectoparasite fauna of S. barbatus in central and southern Chile. A total of 125 individuals caught with mist nets were examined alive; a total of 22 parasites were found dead and were exposed to parasit autopsy. The extracted parasites were preserved in 70% alcohol for subsequent mounting and identification. Ectoparasites were found in 56 black-chinned siskins (38%); 48 of them (33%) had 870 mites - 680 feather mites (Astigmata: Analgoidea) were identified as Proctophyllodes spini, 167 as Knemidokoptes jamaicensis, 19 as Strelkoviacarus critesi, and one as Analges passerinus. Moreover, three mites were chiggers belonging to the tribe Schoengastiini (Prostigmata: Trombiculidae). In 21 birds (14%), 54 lice were found, 21 of which were identified as Philopterus roehreri, 18 as Myrsidea serini, and 15 as Ricinus carolynae. Endoparasites were not found in the necropsied individuals. All of the parasites that were found represent new records for Chile, and they also serve as new records of host-parasite associations for S. barbatus.
Pereira, Luis Alberto
Plateurytion roigi sp. nov. (Chilopoda: Geophilomorpha: Geophilidae) is fully described and illustrated from the holotype female from southern Chile (Region X (de Los Lagos region): Palena province). The new species seems particularly similar to P. gracilis (Gervais, 1849) (from Chile and Argentina), to which it is accordingly compared in detail for a confident identification. This is the sixth report of a species of the genus Plateurytion Attems, 1909, from Chile. The others are P. gracilis (Gervais, 1849); P. metopias (Attems, 1903); P. michaelseni (Attems, 1903); P. mundus (Chamberlin, 1955); and P. zapallar (Chamberlin, 1955). New geographic records are given for Plateurytion mauryi Pereira, 2008, which is reported for the first time from San Juan province, up to now only known from the type locality (in Mendoza province), central-western Argentina. Plateurytion yungarum (Pereira, 2005), is reported from the montane cloud forest altitudinal level of the Yungas forest of northwestern Argentina, until now it has only been recorded from the (lowest) montane forest altitudinal level of the Yungas.
Solanum section Petota (Solanaceae), which includes the cultivated potato (Solanum tuberosum) and its wild relatives, contains over 150 wild species distributed from the southwestern U.S.A. (38°N) to central Argentina and adjacent Chile (41°S). This catalog includes all species from the Southern Con...
Bravo, Macarena; de Los Angeles Gallardo, Ma; Luna-Jorquera, Guillermo; Núñez, Paloma; Vásquez, Nelson; Thiel, Martin
Anthropogenic marine debris (AMD) is an ubiquitous problem, which has motivated public participation in activities such as beach surveys and clean-up campaigns. While it is known that beaches in the SE Pacific are also affected by this problem, the quantities and types of AMD remain largely unknown. In the context of an outreach project, volunteers (approximately 1500 high-school students) participated in a nation-wide survey of AMD on 43 beaches distributed randomly along the entire Chilean coast (18 degrees S to 53 degrees S). The mean density of AMD was 1.8 items m(-2) and the major types were plastics, cigarette butts and glass. Densities in central Chile were lower than in northern and southern Chile, which could be due to different attitudes of beach users or to intense beach cleaning in central regions. We suggest that public participation in surveys and cleaning activities will raise awareness and thereby contribute to an improvement of the situation.
This address seeks to explain in brief the historical background and political, economic, and social conditions leading to the democratic election of a Marxist president in Chile. A historical sketch of Chilean government from independence in 1810 is provided with a description of the situation just before Salvador Allende's election in 1969. Some…
... 7 Agriculture 5 2012-01-01 2012-01-01 false Citrus from Chile. 319.56-38 Section 319.56-38... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Fruits and Vegetables § 319.56-38 Citrus from Chile. Clementines (Citrus reticulata Blanco var. Clementine), mandarins (Citrus reticulata...
... 7 Agriculture 5 2014-01-01 2014-01-01 false Citrus from Chile. 319.56-38 Section 319.56-38... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Fruits and Vegetables § 319.56-38 Citrus from Chile. Clementines (Citrus reticulata Blanco var. Clementine), mandarins (Citrus reticulata...
... 7 Agriculture 5 2013-01-01 2013-01-01 false Citrus from Chile. 319.56-38 Section 319.56-38... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Fruits and Vegetables § 319.56-38 Citrus from Chile. Clementines (Citrus reticulata Blanco var. Clementine), mandarins (Citrus reticulata...
Whitmore, Marilyn P.
This paper assessing the development of libraries in Chile focuses on the public library movement. An introductory section on the historical, economic, technological, and educational background of Chile is provided, as well as a discussion of the adverse effect of the military regime on the country's cultural life. The main part of the paper…
Manuel Contreras, was sentenced to two life prison terms in July 2008 for organizing the 1974 double assassination of General Carlos Prats and his wife...Hornbeck. 48 Eva Vergara , “EEUU Vuelve a Escuchar a Latinoamérica, Dice Biden en Chile,” Associated Press, March 28, 2009. Chile: Political and
Walter, Amy R.
This project seeks to determine the effect of the mass media on political attitudes and behaviors in Chile between the years 1970 and 2000. The relationship between the media and "political socialization" is just now gaining recognition in scholarly research, and Chile offers an excellent case study. This paper traces these two variables…
Skewes, Juan Carlos; Sampaio, Carlos Alberto Cioce; Conway, Frederick J.
Honors programs are rare in Latin America, and in Chile they were unknown before 2003. At the Universidad Austral de Chile, an interdisciplinary group of scholars linked to environmental studies put forward a pilot project for implementing a new experience in higher education. Challenged by an educational environment where (i) apathy and…
McWhirter, Ellen Hawley; McWhirter, Benedict T.
In this article, the lens of critical psychology is applied to adolescent career development and vocational guidance in Chile. The authors describe and critique the status of adolescent vocational guidance in Chile, the reproduction of extant social inequities in Chilean education, and offer recommendations for enhancing vocational guidance…
Intelligence Unit, September 2010. 30 Gobierno de Chile, “Situación terremoto zona centro sur (Actualiza reporte),” March 1, 2010; “Bachelet decreta...desde terremoto de 1985,” El Mercurio, March 1, 2010. 31 President Sebastian Piñera, “Del Chile del bicentenario al país de las oportunidades
This paper presents results of site-response experiments performed five months after the M//s equals 7. 8 Central Chile Earthquake of 3 March 1985. The objectives of the experiments performed are to identify amplification due to topography and geology. Topographical amplification at Canal Beagle, a subdivision of Vina del Mar, was hypothesized immediately after the main event, when extensive damage was observed on the ridges of Canal Beagle. Spectral ratios determined from aftershock data obtained from a temporary dense array are used to show that there was substantial amplification of motions at the ridges of Canal Beagle.
Cianelli, Rosina; Ferrer, Lilian; Cabieses, Báltica; Araya, Alejandra; Matsumoto, Cristina; Miner, Sarah
Chile is a country with an incipient HIV epidemic. Just as in other countries, disadvantaged groups in Chile are contributing to the increased incidence of the disease. The Mapuche indigenous population is one such group that has been affected by the spread of HIV. However, no prevention programs are tailored to the culturally specific needs of this community. In recognition of this discrepancy, an academic-community partnership was formed to develop an HIV educational module for a Mapuche community. The module was developed for use as part of an already established health-related program. The aims of the module were to identify perceptions about HIV among Mapuches and present information specific to HIV and its prevention. Focus was placed on cultural sensitivity. The module was carried out in connection with a first-aid course in an attempt to increase effectiveness of the intervention by working jointly with an established community program. Sixteen (16) Mapuches participated voluntarily and demonstrated some knowledge regarding HIV, but they lacked an overall understanding as to how it is transmitted and why prevention strategies are affective. Participants correctly identified sexual contact as a means of transmission, but when asked why, one person stated, “I just know it, I read it.” There were significant barriers to communication within the group, secondary to cultural practices related to age and gender. Major obstacles in controlling HIV are the lack of prevention strategies targeted to disadvantaged groups. The module developed for this intervention was the first effort of the Academic Community Partnership established between the Pontificia Universidad Católica de Chile and the Mapuche group around HIV prevention. Continued collaboration between academia and affected communities as well as incorporating HIV information into established programs are effective strategies for delivering prevention information to disadvantaged populations and for
Cabrera, Ileana; And Others
A study of translation as a profession in Chile covered two areas: a diagnostic study of the real need for literary, scientific, and technical translations, and a followup study of graduates of the translation degree program at the Catholic Pontifical University of Chile (Santiago). The analysis considered the relationship between the need for…
Filp, Johanna; Undurrage, Consuelo
This paper examines the current status of programs for preschool children in Chile. Section 1 of the paper provides an overview of the situation of preschool children in Chile. The country's population includes more than 1.6 million children between the ages of 0 and 5 years 11 months, and in urban areas, 18.4 percent of children between the ages…
Reginato, A J; Hollander, J L; Martinez, V; Valenzuela, F; Schiapachasse, V; Covarrubias, E; Jacobelli, S; Arinoviche, R; Silcox, D; Ruiz, F
Studies about chondrocalcinosis in the Chiloe Islands (Chile) showed the high frequency of the disease there and how most of it is aggregated in a few highly involved families. Pedigrees and the high degree of consanguinity among parents of index cases pointed to a recessive inheritance. The presence of common Caucasian anthropological features of genetic value in the patients and the lack of Indian mixture in three of the involved families, documented back to 1600, suggest a Caucasian origin of the mutation. Biochemical studies of the patients' synovial fluid showed a significant rise in pyrophosphate concentration. Calcium, phosphorus, and alkaline phosphatase concentrations were not different from a control group. PMID:168817
... Agreement ACTION: Notice of preparation of the 2012-2014 U.S.-Chile Environmental Cooperation Work Program... suggestions regarding items for inclusion in a new work program for implementing the U.S.-Chile Environmental....-Chile Environmental Cooperation Agreement; (2) the U.S.-Chile 2009-2011 Work Program for...
Vargas Fernández, Luis
When Revista Médica de Chile turns to be 130 years old, the author reflects about the difficulties that scientific and technological creativity faces in Chile, considering that there was a 70 years gap between its historical origin in Chile compared to developed countries. The scientific progress erases the boundaries between Biomedicine and science and technology. This progress has resulted in an improvement in the quality of scientific publications in Revista Medica de Chile. The editorial work has also contributed to this improvement. Revista Medica de Chile has obtained international recognition and stands in a good position as a medical journal in Latin America and Chile.
Cianelli, Rosina; Ferrer, Lilian; Cabieses, Báltica; Araya, Alejandra; Matsumoto, Cristina; Miner, Sarah
Chile is a country with an incipient HIV epidemic. Just as in other countries, disadvantaged groups in Chile are contributing to the increased incidence of the disease. The Mapuche indigenous population is one such group that has been affected by the spread of HIV. However, no prevention programs are tailored to the culturally specific needs of this community. In recognition of this discrepancy, an academic-community partnership was formed to develop an HIV educational module for a Mapuche community. The module was developed for use as part of an already established health-related program. The aims of the module were to identify perceptions about HIV among Mapuches and present information specific to HIV and its prevention. Focus was placed on cultural sensitivity. A total of 16 Mapuches participated voluntarily and showed some knowledge regarding HIV, but they lacked an overall understanding as to how it is transmitted and why prevention strategies are effective. Continued collaboration between academia and affected communities as well as incorporating HIV information into established programs are effective strategies for delivering prevention information to disadvantaged populations and for further understanding their perceptions and health care needs.
Pine, Ronald H.; Miller, Sterling D.; Schamberger, Mel L.
Collections of mammals were made during more than three years of biological investigations in Chile sponsored by the Corporación Nacional Forestal under the aegis of the Peace Corps (Smithsonian Environmental Program). Genera and species hitherto unreported for that country were taken and many useful data concerning distributional patterns of other (mostly little-known) species were gathered. These collections have also proved valuable in better understanding Chilean mammals from a taxonomic point of view and contribute knowledge of the species' natural history. Specimens are to be deposited in the (United States) National Museum of Natural History (USNM) or are to be retained by the Corporación Nacional Forestal, Avda, Bulnes 285, Depto. 401, Santiago. Numbers provided below are field numbers. A final division of specimens between the two institutions has not yet been made. A number of specimens reported here were not taken by Peace Corps personnel but have been obtained by the National Museum of Natural History from other sources. Specimens in the Field Museum of Natural History (FMNH) were used in making comparisons. Some of Fulk's (GWF) specimens are at Texas Tech University. Other are at the Servicio Agricola y Ganadero in Santiago (as are specimens of some introduced species taken by Schamberger). Reise's (DF) are at the Universidad de Chile-Concepción and in his personal collection.
Salinas, Judith; Cancino, Anselmo; Pezoa, Sergio; Salamanca, Fernando; Soto, Marina
The Government of Chile has placed a high priority on health promotion. This is evident in the advances made through its National Plan for Health Promotion (Plan Nacional de Promoción de la Salud) and the Vida Chile National Council for Health Promotion (Consejo Nacional para la Promoción de la Salud Vida Chile). Chaired by the minister of health, Vida Chile is made up of 28 public and private institutions from around the country. Vida Chile has a network of local councils that have been established in the country's comunas (communes, or local-level divisions of the country's provinces) and that include government officials and representatives of local societal and community organizations and private businesses. This report details the methods used to evaluate the National Plan as well as provides a preliminary assessment of the technical and financial results for the 1998-2006 period. Coverage indicators (number of participants; number of accredited health-promoting schools, workplaces, and universities; and number of health promotion events) and the extent of strategy implementation were used to measure the success of the program. Health promotion activities grew markedly during this period. Among the notable accomplishments were the following four: (1) 98% of the communes now have their own community health promotion plan and intersectoral Vida Chile committee to implement the plan, (2) there has been an increase in societal and community groups involved in the health promotion strategies, (3) 34% of the primary and secondary schools have become accredited health-promoting schools, and (4) approximately 20% of the total population benefited directly from community-health-plan activities in 2006. The average per capita cost of the community health plans' activities in 2006 was US$ 6.60. The two most important factors that facilitated the operation of the local health promotion plans were participation by community and societal groups and having an adequate
Lostarnau, Carla; Oyarzún, Jorge; Maturana, Hugo; Soto, Guido; Señoret, Michelle; Soto, Manuel; Rötting, Tobias S; Amezaga, Jaime M; Oyarzún, Ricardo
The main objective of this paper is to present a critical analysis of the stakeholder participation process within the Environmental Impact Assessment System in Chile, after ca. 14 years of being enforced. This analysis is sustained by the description and analysis of the stakeholder participation possibilities in a representative rural area of North-Central Chile. The Environmental Basis Act 19300, enacted in 1994, considers the participation of the local community in the environmental impact assessment of new projects. However, this possibility is very limited and difficult to exert, often resulting in frustration for the participants. This is due to a number of reasons, such as the imbalance of resources and knowledge among the majority of participating communities and project proponents, the complexity and administrative and legal constraints to participation, and the dominant interest of the Central Government in approving investments, specifically in energy and natural resources related projects, which generate wealth and jobs. Also, the State's rush to develop Internet-based communication and management systems has built a barrier for poor, traditional communities. This factor is clearly reflected in the case study considered. Results show that there is generally a significant lack of knowledge about institutions and participation tools. From this base, we intend to raise concern on these selected aspects that could be addressed to improve the effectiveness of the existing framework, both in Chile and in other developing countries, where immature environmental impact assessment and public management systems face similar pressures in relation to the sustainable use of their natural resources. Finally, some basic steps are proposed in order to make the community participation an effective tool for sustainable development.
Reichert, Chr.; Spoc Scientific Shipboard Party, The
Within the scope of the multi-disciplinary SPOC project (Subduction Processes Off Chile) some 8.700 km were recently acquired using marine magnetic, gravity and swath bathymetric methods whereof 5.200 km were surveyed with multi-channel seismics, including three seismic lines with simultaneous onshore observations. The goal of the project is to identify the variety of subduction features and accompanying conditions along the Central Chile segment of the collision zone between the Nazca and S-American plates, i.e. between Coquimbo and Valdivia. An additional line was achieved just south of Chiloe Island entering the submerged Central Valley. The present status of data allows the following observations: the oceanic crust is seg- mented by features like the Juan Fernandez Ridge, the Mocha and Valdivia Fracture Zones, accumulations of seamounts and by distinct parallel fault patterns with various azimuths. From north to south the subduction-induced inclination of the oceanic crust toward the trench decreases while the trench proper widens and the margin slope an- gle increase significantly. In the north clearly extensional normal faulting occurs on the upper and middle slopes, very similar to that observed off North Chile where sub- duction erosion is active. While in the north no bottom simulating reflectors could be observed they occur in the south as local patches. The slope area in the south is over- printed by a faint lineation pattern with a dominant azimuth of some 120 degrees that neatly fits with a mapped pattern onshore with the same azimuth. The pronounced forearc basins in the south are often accompanied by outer arc highs and strikingly narrow accretionary wedges. The latter are in contrast with the high convergence rate of more than 8 cm/yr and the relatively thick trench filling of up to more than 2.000 m. Thus, a non-accretionary subduction type is suggested, here.
Arcos, Dagoberto F.; Cubillos, Luis A.; P. Núñez, Sergio
The jack mackerel fishery is one of the most important resources on the South Eastern Pacific Ocean off Chile, with landings higher than 3 million tonnes between 1990 and 1996. During 1997-1998, remarkable changes occurred in the length structure of jack mackerel catches, as juveniles (<26 cm FL) dominated the fishing grounds. That was attributed to the environmental effects of the 1997-98 El Niño on the feeding grounds of the jack mackerel off central-southern Chile. Anomalous sea surface temperatures were first detected in June 1997 and persisted into 1998. The response of the incidence of juveniles lagged one year after the ENSO phenomenon affected central-southern Chile, whereas there was a direct relationship between the proportion of juveniles and the intrusion of the 15°C isotherm towards the south. This isotherm reached its most southerly distribution in 1997-98, as a consequence of the El Niño. Jack mackerel is an oceanic and highly migrating species, so we propose that El Niño conditions affected the migratory pathway of the juveniles. It is postulated that the restoration of the nursery habitat north of 30°S may be delayed by more than 3-4 years. New juveniles will dominate in northern areas in the short-term, whereas the juveniles that migrated to southern areas during 1997-1999 are not expected to return back north. At present, the real situation of the stock is far from certain, but we think that environmental impacts associated to the El Niño can not be overlooked when planning the management of the jack mackerel fishery.
Bernhardt, Anne; Hebbeln, Dierk; Regenberg, Marcus; Lückge, Andreas; Strecker, Manfred. R.
Understanding the links between terrigenous sediment supply and marine transport and depositional processes along tectonically active margins is essential to decipher turbidite successions as potential archives of climatic and seismic forcings and to comprehend timing and quantity of marine clastic deposition. Sequence stratigraphic models predict coarse-grained terrigenous sediment delivery to deep-marine sites mainly during sea-level fall and lowstand. Marine clastic deposition during periods of transgression and highstand has been attributed to the continued geomorphic connectivity between terrestrial sediment sources and marine sinks (e.g., rivers connected to submarine canyons) often facilitated by narrow shelves, high sediment supply causing delta migration to the shelf edge, and/or abrupt increases in sediment supply due to climatic variability or catastrophic events. To decipher the controls on Holocene highstand turbidite deposition, we analyzed twelve sediment cores of spatially disparate, coeval Holocene turbidite systems along the Chile margin (29-40°S) with changing climatic and geomorphic characteristics but uniform changes of sea level. Intraslope basins in north-central Chile (29-33°S) offshore a narrow to absent shelf record a shut-off of turbidite activity during the Holocene. In contrast, core sites in south-central Chile (36-40°S) offshore a wide continental shelf have repeatedly experienced turbidite deposition during sea-level highstand conditions, even though most of the depocenters are not connected via canyons to sediment sources. The interplay of stable high sediment supply related to strong onshore precipitation in combination with a wide shelf, over which undercurrents move sediment towards the shelf edge, appears to control Holocene turbidite sedimentation and sediment export to the deep sea.
ESO and the Government of Chile launched today the book "10 Years Exploring the Universe", written by the beneficiaries of the ESO-Chile Joint Committee. This annual fund provides grants for individual Chilean scientists, research infrastructures, scientific congresses, workshops for science teachers and astronomy outreach programmes for the public. In a ceremony held in Santiago on 19 June 2006, the European Organisation for Astronomical Research in the Southern Hemisphere (ESO) and the Chilean Ministry of Foreign Affairs marked the 10th Anniversary of the Supplementary Agreement, which granted to Chilean astronomers up to 10 percent of the total observing time on ESO telescopes. This agreement also established an annual fund for the development of astronomy, managed by the so-called "ESO-Chile Joint Committee". ESO PR Photo 21/06 ESO PR Photo 21/06 Ten Years ESO-Chile Agreement Ceremony The celebration event was hosted by ESO Director General, Dr. Catherine Cesarsky, and the Director of Special Policy for the Chilean Ministry of Foreign Affairs, Ambassador Luis Winter. "ESO's commitment is, and always will be, to promote astronomy and scientific knowledge in the country hosting our observatories", said ESO Director General, Dr. Catherine Cesarsky. "We hope Chile and Europe will continue with great achievements in this fascinating joint adventure, the exploration of the universe." On behalf of the Government of Chile, Ambassador Luis Winter outlined the historical importance of the Supplementary Agreement, ratified by the Chilean Congress in 1996. "Such is the magnitude of ESO-Chile Joint Committee that, only in 2005, this annual fund represented 8 percent of all financing sources for Chilean astronomy, including those from Government and universities", Ambassador Winter said. The ESO Representative and Head of Science in Chile, Dr. Felix Mirabel, and the appointed Chilean astronomer for the ESO-Chile Joint Committee, Dr. Leonardo Bronfman, also took part in the
Balanda, Monserrat; Quiero, Andrea; Vergara, Nicolás; Espinoza, Gloria; Martín, Héctor San; Rojas, Giovanna; Ramírez, Eugenio
Cervical cancer is the fourth most common malignancy in women worldwide. In Chile, cervical cancer is the second leading cause of death among women of reproductive age, causing more than 600 deaths annually. This study was carried out to determine the burden and confirm the predominant human papillomavirus (HPV) genotypes among women presenting for cervical cancer screening in public health services in Chile. Women aged 18-64 years residing in the north and central areas covered by six primary care centers of Santiago, Chile, were invited to participate from March 2014 to August 2015. Cervical swabs were examined both HPV genotyping by PCR and Reverse Line Blot, and cervical cytology by Pap testing. A total of 1738 women were included in this study: 11.1 % were HPV positive, 9.7 % were high-risk types positive, 3.2 % were low-risk types positive, 1.4 % were Pap positive and 0.9 % were positive by both tests. The four most predominant genotypes were 16, 66, 51 and 59, with prevalence of 2.8, 1.4, 1.2 and 1.2 %, respectively. Multiple HPV infections were detected among 3.8 % participants. Age-specific prevalence of HPV showed a peak in HPV infection at younger ages (≤30 years), declining to a plateau in middle age. Among women with normal cytology, the 9.4 % were HPV positive, while 58.3 % of women with abnormal cytology were HPV positive. These findings show new epidemiological data confirming HPV 16 and 66 as the most predominant genotypes in Chile. These data are important for design successful strategies for prevention of cervical cancer in Chile.
Fernández, Leonardo D; Lara, Enrique; Mitchell, Edward A D
Bringing together more than 170 years of data, this study represents the first attempt to construct a species checklist and analyze the diversity and distribution of testate amoebae in Chile, a country that encompasses the southwestern region of South America, countless islands and part of the Antarctic. In Chile, known diversity includes 416 testate amoeba taxa (64 genera, 352 infrageneric taxa), 24 of which are here reported for the first time. Species-accumulation plots show that in Chile, the number of testate amoeba species reported has been continually increasing since the mid-19th century without leveling off. Testate amoebae have been recorded in 37 different habitats, though they are more diverse in peatlands and rainforest soils. Only 11% of species are widespread in continental Chile, while the remaining 89% of the species exhibit medium or short latitudinal distribution ranges. Also, species composition of insular Chile and the Chilean Antarctic territory is a depauperated subset of that found in continental Chile. Nearly, the 10% of the species reported here are endemic to Chile and many of them are distributed only within the so-called Chilean biodiversity hotspot (ca. 25° S-47° S). These findings are here thoroughly discussed in a biogeographical and evolutionary context.
Gutierrez Roldan, H G
"The paper refers to the amount and some characteristics of the Spanish, Italian and Portuguese immigration to Chile during the period 1860-1930. It is compared with [movements to] Argentina, Brazil, Cuba and Uruguay.... Different information sources are used and in spite of data weakness, the low preference for Chile of the European migratory flows is ratified as compared with those to Argentina.... It is pointed out that the migratory flows to Latin America, in particular to Chile, are associated, on the one hand, with the favourable... European [immigration] policy in this country and on the other hand with the huge European emigration overseas during that period." (SUMMARY IN ENG)
Gurbuz, Gokhan; Jin, Shuanggen
The Mw=8.8 Maule earthquake occured on 27 February 2010 near the coast of central Chile, which killed more than 500 people and caused large economic losses. Meanwhile, the earthquake triggered a tsunami with devastating several coastal towns in south-central Chile and damaging the port at Talcahuano. Several geodetic observations data and methods were used to investigate pre-seismic ionospheric disturbances and co-seismic crustal deformations on this eartquake, such as InSAR and GPS measurements. However, the precursor and detailed rupture properties of this earthquake are still not clear. In this study tropospheric anomalies following the Mw=8.8 Maule earthquake are investigated using zenith tropospheric delay (ZTD) computed from GPS observations. Results show tropospheric anomalies during and after the mainchock at CONZ that is the closest GPS station to the epicenter and VALP station that is close to the fault rupture. The possible mechanism of seismic-tropospheric disturbances is discussed, which will be further studied in near future.
Internal Medicine, as a comprehensive discipline, has become increasingly dismembered during the last decades due to several reasons, some of which are the growing complexities of its practice, its obstinate confinement to hospital-based practice, its generation of and subsequent disfunction from general internal medicine and the medical subspecialities. In Chile internal medicine is currently organized in three levels of patient care, each of anarchical and distortioned proportions. These levels do not constitute a fluent network of progressive patient care but rather an heterogeneous combination of ironclad compartments in search of their own autonomy. A few of the many problems and challenges that internal medicine faces in Chile are: (a) in primary care medicine, problem-solving abilities must be improved and programmed care must be privileged over free choice. Specialist in general medicine must be assigned to primary care and multiprofessional teams must be strengthened; (b) Secondary care is underdeveloped due to the waning prestige of internal medicine and waxing attractiveness of its subspecialities. Programmed formation of specialist in internal medicine has been so far rigorous and demanding, but excessive in number in relation to available post. This leads trained internist to practice as subspecialist, without having the adequate conditions for such a practice. To avoid this situation, the scope of internal medicine emergency wards, integral medicine clinics, and medical student teaching should be handed over to it; (c) Tertiary care is a task of subspecialist. It is not known how many subspecialist are required, or how many physicians are currently practicing as a subspecialist. Most of the currently practicing subspecialist are self-qualified or have received quick training through short rotations by not always well-qualified centers. Many are only former internal medicine residents. In this setting, it is not possible to devise a prospective plan of
Holmgren, J; Reyes, J; Colombo, M; Blanco, M A
Duchenne muscular dystrophy is one of the best known forms of muscular dystrophy. The incidence in different countries varies from 130 to 390 per million male live births. Becker variety may be considered a mild form of Duchenne dystrophy, with an incidence 10 times lower. A sex linked recessive inheritance is involved in both forms, the affected gene is placed at locus X21. The incidence of both forms in Chile is similar to that reported worldwide, and has been increasing since 1950. Increased CK and LDH levels are confirmed in patients, and overall, they are also higher in female carriers. However only 26% of carriers have increased CK levels and 21% increased LDH levels, compared to normal subjects. Electromyograms show myopathic characteristics in all carrier women. The scope of a prospective clinical, genetic and epidemiologic study currently underway is discussed.
The voucher model of financing schooling is becoming increasingly common throughout Latin America, with at least 12 countries using vouchers or voucher-like schemes. The present study focuses on the voucher models of Colombia and Chile, which have the most extensive programs of this type and those of the longest standing in the region. Using empirical evidence, the author compares the two models along four evaluative dimensions: educational quality, segregation, choice and socialization. After weighing the successes and weaknesses of each system, he concludes that, among other characteristics, the most effective and equitable voucher model features: (a) a flexible interpretation of educational quality; (b) financial grants which target solely the poor; (c) vouchers which cover the entire cost of tuition; (d) open enrolment at participating schools; (e) the participation of both secular and religious private schools; (f) accessible and meaningful information to parents; and (g) strong systems of accountability.
Moreno M, Claudia
Several parasitic diseases affect the skin and appendages in humans, the most common are head lice and scabies. Both diseases have worldwide distribution with geographical variations. In Chile, the reported prevalence of head lice is 20-25% and of scabies 1-5%. Other ectoparasites include fleas and mite, causing transient parasitosis related to human and animal contact. These parasites are associated with various factors such as poor personal hygiene, promiscuity, long hair, crowding, and sharing of combs, among others. Various effective pharmacological therapies are available, which base on several active compounds. Important therapeutic options include topical treatments with pyrethroids, lindane, crotamiton, and malathion as well as oral medications such as ivermectin, which is used in case of drug intolerance, poor treatment response, infections with multiple parasites or concomitant bacterial infections. For some drugs, resistance has been reported in patients received multiple dosis.
Harth, Erika; Matsuda, Luis; Hernández, Cristina; Rioseco, Maria L.; Romero, Jaime; González-Escalona, Narjol; Martínez-Urtaza, Jaime
Disease outbreaks caused by Vibrio parahaemolyticus in Puerto Montt, Chile, began in 2004 and reached a peak in 2005 at 3,600 clinical cases. Until 2006, every analyzed case was caused by the serovar O3:K6 pandemic strain. In the summer of 2007, only 475 cases were reported; 73% corresponded to the pandemic strain. This decrease was associated with a change in serotype of many pandemic isolates to O3:K59 and the emergence of new clinical strains. One of these strains, associated with 11% of the cases, was genotypically different from the pandemic strain but contained genes that were identical to those found on its pathogenicity island. These findings suggest that pathogenicity-related genes were laterally transferred from the pandemic strain to one of the different V. parahaemolyticus groups comprising the diverse and shifting bacterial population in shellfish in this region. PMID:19193258
Rojo, Patricio; Jenkins, James; Hoyer, Sergio; Jones, Matías
We present and highlight the first results of the three main exoplanet surveys we are currently conducting at Universidad de Chile: CHEPS, Red Giant Exoplanets (radial velocity), and TraMoS (transit lightcurves). We have several interesting candidates at the Calan-Hertfordshire Extrasolar Planet Search (CHEPS) project, which is aimed at searching for the currently missing southern bright transiting planets at a few m/s radial velocity precision. Using the same technique, we are also characterizing the planetary population in a constrained sample of Red Giant stars. The Transit Monitoring from the South (TraMoS) project is aimed both at improving transit parameters and at detecting any kind of lightcurve variability from several known southern exoplanet systems.
Delannoy, Jaime; Heuffemann, Carolina; Ramirez, Daniel; Galvez, Fernando
The primary purpose of this work was to investigate about the present acoustic conditions of used architectonic spaces in Santiago of Chile for orchestras of classic music performance. The studied halls were three: Aula Magna Universidad de Santiago, Teatro Municipal de Nunoa, and Teatro Baquedano. The used methodology was based on studies made by L. Beranek, M. Barron, among others, in concert halls worldwide. As it guides, for the measurement procedure, physical parameters RT, EDT, C50, C80, LF, BR, G, U50 were evaluated according to norm ISO 3382. On the other hand, it has been defined, to proposal way, a questionnaire of subjective valuation directed to musicians, specialized conductors, and listeners.
Preston, Sandra Lee; Arnett, Dinah; Hardy, Eduardo; Cabezón, Sergio; Spuck, Tim; Fields, Mary Sue; Smith, R. Chris
The first Chile-U.S. Astronomy Education Outreach Summit occurred March 22-28, 2015. The Summit was organized and supported by the U.S. Embassy in Chile, Associated Universities Inc., Association of Universities for Research in Astronomy, the Carnegie Institution for Science, the Image of Chile Foundation, the National Science Foundation, and La Comisión Nacional de Investigación Científica y Tecnológica. The Summit brought together a team of leading experts and officials from Chile and the U.S. to share best practices in astronomy education and outreach. In addition, Summit participants discussed enhancing existing partnerships, and building new collaborations between U.S. Observatories and astronomy education outreach leaders in Chile.The Summit was an exciting and intense week of work and travel. Discussions opened in Santiago on March 22 with a variety of astronomy education and public outreach work sessions, a public forum, and on March 23 the U.S. Embassy sponsored a Star Party. On Tuesday, March 24, the Summit moved to San Pedro de Atacama, where activities included work sessions, a visit to the Atacama Large Millimeter/Submillimeter Array telescope facilities, and a second public forum. From San Pedro, the team traveled to La Serena for additional work sessions, visits to Gemini and Cerro Tololo, a third public forum, and the closing session. At each stop, authorities and the broader community were invited to participate and provide valuable input on the current state, and the future, of astronomy education and public outreach.Following the Summit a core working committee has continued meeting to draft a “roadmap document” based on findings from the Summit. This document will help to identify potential gaps in astronomy outreach efforts, and how the U.S. facilities and Chilean institutions might work together strategically to address these needs. The first draft of this “roadmap document” will be made available for comment in both Spanish and
Ruiz, Sergio; Klein, Emilie; del Campo, Francisco; Rivera, Efrain; Metois, Marianne; León, Sergio; Fuenzalida, Amaya; Poli, Piero; Vigny, Christophe; Baez, Juan Carlos; Maksymowicz, Andrei; Ruiz, Javier; Grandin, Raphael; Vargas, Gabriel; Leyton, Felipe; Madariaga, Raúl; Fleitout, Luce
The 2014 Iquique Mw 8.2, and 2015 Illapel Mw 8.3 earthquakes occurred inside of the mega-rupture zones of 1877 in Northern Chile and 1730 in Central Chile, respectively. 1877 and 1730 are the two largest megathrust events that probably controls the seismic cycle of these two zones, recent paleo-seismological studies propose recurrence intervals between ~200 and ~650 years for these giant earthquakes. The two 2014 and 2015 events were very well recorded by large permanent broadband and strong motion networks, temporary broadband digital stations, high rate GPS instruments and InSAR images. With this large dataset we attempt to understand the processes of interaction between slow and fast deformation in these zones, which produced these events of magnitude Mw~8.0. We study the upper plate deformation before both events using the continuous time displacement of GPS antennas. Both earthquakes show precursory phases: Iquique was preceded by a slow slip event and Illapel was preceded by a deep transient slow slip produced by postseismic deformation due to the Mw 8.8 2010 Maule mega-earthquake. On the other hand, a remarkable feature of the Iquique and Illapel coseismic ruptures was their nucleation processes. Both were preceded in their first 20 seconds by small events that released a tiny fraction of the total seismic energy. The largest release of seismic energy was generated at the end of these precursory ruptures. We can interpret this process in terms of a simple asperity model, where the boundaries of the rupture are controlled by the plate interface. The areas surrounding both rupture zones were weakly coupled and a presented concentration of swarms and repeating events. Finally, we relocated and computed moment tensors of the events of magnitude Mw ≥ 4.5. Most of the fore- and after -shocks of both earthquakes are interplate events surrounding the rupture zones of the main events. However, in the Iquique earthquake these events are located in a band of about 50
Baginsky, Cecilia; Brito, Belén; Scherson, Rosita; Pertuzé, Ricardo; Seguel, Oscar; Cañete, Alejandro; Araneda, Cristian; Johnson, Warren E
In spite of potentially being an important source of rhizobial diversity and a key determinant of common bean productivity, there is a paucity of data on Rhizobium genetic variation and species composition in the important bean producing area of Chile and only one species has been documented (Rhizobium leguminosarum). In this study, 240 Rhizobium isolates from Torcaza bean (Phaseolus vulgaris L.) nodules established in the highest bean producing area in Chile (33°34'S-70°38'W and 37°36'S-71°47'W) were characterized by PCR-RFLP markers for nodC gene, revealing eight banding patterns with the polymorphic enzyme Hinf I. The locality of San Agustín de Aurora in Central Chile (35°32'S-71°29'W) had the highest level of diversity. Isolates were classified by species using PCR-RFLP markers for 16S rDNA gene and were confirmed by sequencing an internal fragment of the 16S rDNA gene. The results confirmed the presence of R. leguminosarum and three other species of rhizobia nodulating beans in South Central Chile (R. etli, R. tropici and R. leucaenae). R. tropici and R. leucaenae showed the least genetic variation and were most commonly identified in acid soils, while R. etli was the most common species in slightly acidic to moderately alkaline soils, with higher levels of organic matter content. R. leguminosarum was identified in almost all soils, was the most genetically diverse, and was the most common, being documented in soils with pH that ranged between 5.3 and 8.2, and with organic matter content between 2.1 and 4 %.
Vargas, Héctor A; Hausmann, Axel
Three species of geometrid moths are reported from the extreme North of Chile. All three are new for the Chilean fauna: Scopula umbilicata (Fabricius, 1794) (Sterrhinae), Cataspilates grisescens Warren, 1897, and Pero obtusaria Prout, 1928 (Ennominae).
Reyes Budelovsky, H
The first issue of Revista Médica de Chile was printed in July, 1872. Since then, it has been published monthly, interrupted only for a few months during a Chilean civil war (1891). This medical journal has been devoted mainly to clinical topics in internal medicine, but currently it includes an increasing proportion of research papers in other biomedical and preclinical subjects. This journal is included in the most important international indexes of biomedical publications. Most issues cover also medical education, public health, the ethics of clinical and experimental research, medical administration and the history of medicine. The evolution of medicine in Chile along 125 years is clearly reflected in the contents of this journal. Revista Médica de Chile is one of the oldest medical journals in the world, particularly among those published in Spanish, and a top ranking biomedical publication in Chile.
... if the fruit is fumigated either in Chile or at the port of first arrival in the United States with methyl bromide for B. chilensis in accordance with part 305 of this chapter. An APHIS inspector...
... if the fruit is fumigated either in Chile or at the port of first arrival in the United States with methyl bromide for B. chilensis in accordance with part 305 of this chapter. An APHIS inspector...
Beaucournu, Jean-Claude; Moreno, Lucila; González-Acuña, Daniel
This study presents a revision of the fleas (Siphonaptera) in Chile, gathered from 1993-2013 in response to a request to update our knowledge of the fauna of this country, as catalogued by Beaucournu & Gallardo in 1991 and 1992. For each taxon we give the depository of the type, the main references concerning it, its general distribution, particularly in Chile, and its known hosts, mainly in this country. Our review of the existing literature on fleas of Chile gives information on a total of 8 families, 11 subfamilies, 31 genera, 9 subgenera and 112 species (with 11 subspecies). The hosts are represented by 21 families of mammals (91 species) and 16 of birds (27 species). In addition we present 21 new reports of fleas for Chile and 165 new localities.
Montiel, Américo; Hilbig, Brigitte; Rozbaczylo, Nicolás
The Paraonidae are a polychaete family of small body size which have not been reported for Chile until recently. Mainly due to improved sample-processing methods, research campaigns carried out in 1994 and 1996 on three areas off southern Chile have yielded numerous records. Several species proved to be new to the Chilean polychaete fauna, including species that have been known previously only from Antarctic areas. These new records and range extensions are reported in this paper.
Navarro Rosenblatt, Deborah; Durán Agüero, Samuel
Gallbladder cancer is the most malign neoplasm of the biliary tract. Chile presents the third highest prevalence of gallbladder cancer in the Americas, being Chilean women from the city of Valdivia the ones with the highest prevalence. The main risk factors associated with gallbladder cancer are: sex, cholelithiasis, obesity, ethnicity, chronic inflammation, history of infection diseases such as Helicobacter pyloriand Salmonellaand family history of gallbladder cancer. In Chile gallbladder cancer mortality is close to prevalence level. This is related to the silent symptomatology of this cancer, as well as the lack of specific symptoms. The high prevalence of obesity and infectious diseases present in Chile are two of the main risk factors of gallbladder cancer and Chile has prevalence of obesity close to 30%. The aim of this literary review is to inform and summarize the main risk factors of gallbladder cancer that are prevalent in Chile, in order to be able to focus preventive and management interventions of this risk factor for the reduction in prevalence and mortality of gallbladder cancer in Chile.
Cabrera, Elsa; Carlson, Carole A.; Brownell, Robert L.
Since 1970, blue whales (Balaenoptera musculus) have been seen feeding in the waters off southern Chile during the summer and autumn (December to May). Investigation of the genetic, acoustic and morphological characteristics of these blue whales shows that they are a distinct but unnamed subspecies, called the Chilean blue whales. Photo-identification surveys have been conducted in the waters off northwestern Isla Grande de Chiloé, southern Chile from 2004–2012 and Isla Chañaral, central Chile in 2012. Over this time, 1,070 blue whales were encountered yielding, after photo-quality control, 318 and 267 unique photographs of the left and right side of the flank respectively. Using mark-recapture analysis of left and right side photographs collected from Isla Grande de Chiloé (2004–2012), open population models estimate that ~570–760 whales are feeding seasonally in this region. POPAN superpopulation abundance estimates for the same feeding ground in 2012 are 762 (95% confidence intervals, CI = 638–933) and 570 (95% CI 475–705) for left and right side datasets respectively, very similar to results from closed population models. Estimates of trend revealed strong variation in abundance, peaking in 2009 and [suggesting] fluctuating use in the survey area over time, likely related to the density of their prey. High inter-annual return rates suggest a degree of site-fidelity of individuals to Isla Grande de Chiloé and that the number of whales using this feeding ground is relatively small. PMID:28081160
Galletti Vernazzani, Barbara; Jackson, Jennifer A; Cabrera, Elsa; Carlson, Carole A; Brownell, Robert L
Since 1970, blue whales (Balaenoptera musculus) have been seen feeding in the waters off southern Chile during the summer and autumn (December to May). Investigation of the genetic, acoustic and morphological characteristics of these blue whales shows that they are a distinct but unnamed subspecies, called the Chilean blue whales. Photo-identification surveys have been conducted in the waters off northwestern Isla Grande de Chiloé, southern Chile from 2004-2012 and Isla Chañaral, central Chile in 2012. Over this time, 1,070 blue whales were encountered yielding, after photo-quality control, 318 and 267 unique photographs of the left and right side of the flank respectively. Using mark-recapture analysis of left and right side photographs collected from Isla Grande de Chiloé (2004-2012), open population models estimate that ~570-760 whales are feeding seasonally in this region. POPAN superpopulation abundance estimates for the same feeding ground in 2012 are 762 (95% confidence intervals, CI = 638-933) and 570 (95% CI 475-705) for left and right side datasets respectively, very similar to results from closed population models. Estimates of trend revealed strong variation in abundance, peaking in 2009 and [suggesting] fluctuating use in the survey area over time, likely related to the density of their prey. High inter-annual return rates suggest a degree of site-fidelity of individuals to Isla Grande de Chiloé and that the number of whales using this feeding ground is relatively small.
Carvajal, Matías; Gubler, Alejandra
We investigated the effect that along-dip slip distribution has on the near-shore tsunami amplitudes and on coastal land-level changes in the region of central Chile (29°-37°S). Here and all along the Chilean megathrust, the seismogenic zone extends beneath dry land, and thus, tsunami generation and propagation is limited to its seaward portion, where the sensitivity of the initial tsunami waveform to dislocation model inputs, such as slip distribution, is greater. We considered four distributions of earthquake slip in the dip direction, including a spatially uniform slip source and three others with typical bell-shaped slip patterns that differ in the depth range of slip concentration. We found that a uniform slip scenario predicts much lower tsunami amplitudes and generally less coastal subsidence than scenarios that assume bell-shaped distributions of slip. Although the finding that uniform slip scenarios underestimate tsunami amplitudes is not new, it has been largely ignored for tsunami hazard assessment in Chile. Our simulations results also suggest that uniform slip scenarios tend to predict later arrival times of the leading wave than bell-shaped sources. The time occurrence of the largest wave at a specific site is also dependent on how the slip is distributed in the dip direction; however, other factors, such as local bathymetric configurations and standing edge waves, are also expected to play a role. Arrival time differences are especially critical in Chile, where tsunamis arrive earlier than elsewhere. We believe that the results of this study will be useful to both public and private organizations for mapping tsunami hazard in coastal areas along the Chilean coast, and, therefore, help reduce the risk of loss and damage caused by future tsunamis.
Mohr, Christian; Manga, Michael; Wang, Chi-yuen; Korup, Oliver
Both coseismic static stress and dynamic stresses associated with seismic waves may cause responses in hydrological systems. Such responses include changes in the water level, hydrochemistry and streamflow discharge. Earthquake effects on hydrological systems provide a means to study the interaction between stress changes and regional hydrology, which is otherwise rarely possible. Chile is a country of frequent and large earthquakes and thus provides abundant opportunities to study such interactions and processes. We analyze streamflow responses in Chile to several megathrust earthquakes, including the 1943 Mw 8.1 Coquimbo, 1950 Mw 8.2 Antofagasta, 1960 Mw 9.5 Valdivia, 1985 Mw 8.0 Valparaiso, 1995 Mw 8.0 Antofagasta, 2010 Mw 8.8 Maule, and the 2014 Mw 8.2 Iquique earthquakes. We use data from 716 stream gauges distributed from the Altiplano in the North to Tierra del Fuego in the South. This network covers the Andes mountain ranges, the central valley, the Coastal Mountain ranges and (mainly in the more southern parts) the Coastal flats. We combine empirical magnitude-distance relationships, machine learning tools, and process-based modeling to characterize responses. We first assess the streamflow anomalies and relate these to topographical, hydro-climatic, geological and earthquake-related (volumetric and dynamic strain) factors using various classifiers. We then apply 1D-groundwater flow modeling to selected catchments in order to test competing hypotheses for the origin of streamflow changes. We show that the co-seismic responses of streamflow mostly involved increasing discharges. We conclude that enhanced vertical permeability can explain most streamflow responses at the regional scale. The total excess water released by a single earthquake, i.e. the Maule earthquake, yielded up to 1 km3. Against the background of megathrust earthquakes frequently hitting Chile, the amount of water released by earthquakes is substantial, particularly for the arid northern
Frias, T.; Trigo, R. M.; Garreaud, R.
The Andes Cordillera induces considerable disturbances on the structure and evolution of the pressure systems that influences South America. Different weather types for southern South America are derived from the daily maps of geopotential height at 850hPa corresponding to a 42 year period, spanning from 1958 to 2000. Here we have used the ECWMF ERA-40 reanalysis dataset to construct an automated version of the Lamb Weather type (WTs) classification scheme (Jones et al., 1993) developed for the UK. We have identified 8 basic WTs (Cyclonic, Anticyclonic and 6 main directional types) following a similar methodology to that previously adopted by Trigo and DaCamara, 2000 (for Iberia). This classification was applied to two regions of study (CLnorth and CLsouth) which differ 20° in latitude, so that the vast Chile territory could be covered. Then were assessed the impact of the occurrence of this weather types in precipitation in Chile, as well as in the distribution of precipitation and temperature fields (reanalysis data) in southern half of South America. The results allow to conclude that the precipitation in central region of Chile is largely linked with the class occurrence (concerning CLnorth) of cyclonic circulation and of West quadrant (SW, W and NW), despite of it's relatively low frequency. In CLsouth, for its part, it is verified that the most frequent circulation is from the west quadrant, although the associated amount of rainfall is lower than in CLnorth. There was also a general decrease of precipitation at local weather stations chosen in the considered period of study, particularly in austral winter.
Schurr, B.; Asch, A.; Sodoudi, F.; Manzanares, A.; Ritter, O.; Klotz, J.; Chong-Diaz, G.; Barrientos, S.; Villotte, J.-P.; Oncken, O.
Fast convergence between the oceanic Nazca and the continental South American plate is accommodated by recurrent rupture of large segments of the two plates' interface. The resulting earthquakes are among the largest and, for their sizes, most frequent on Earth. Along the Chilean and southern Peruvian margin, all segments have ruptured at least once in the past 150 years for which there exist historic and/or instrumental records. The one segment that is most mature for re-rupture stretches for more than 500 km along the northernmost Chilean coast between roughly -23° and -18° latitude. It last broke in 1877 in a magnitude ~8.8 earthquake, triggering a major Tsunami. From the historical record, it has been known to have a recurrence cycle of approximately 110 years. The adjoining segments to the north and south broke rather recently in 1995 and 2001 in M>8 earthquakes and an M 7.7 earthquake encroached the southern part of the gap in 2007. The IPOC project intends to investigate this segment of the Nazca-South American plate boundary, on which a strong to devastating earthquake is expected to occur within the next years, by monitoring at a variety of time-scales deformation, seismicity, and magnetotelluric fields in the subduction zone at the closing stages of the interseismic cycle before and possibly during occurrence of a big earthquake. For that purpose, installation of long-term observatories in Northern Chile started in 2006 in a close cooperation of the Universidad de Chile (Santiago, Chile), the Universidad Catolica del Norte (Antofagasta, Chile), the Institut de Physique du Globe de Paris (Paris, France), and the German Research Centre for Geosciences (GFZ, Potsdam, Germany). Currently we are operating 14 modern seismological stations equipped with STS-2 broadband seismometers and accelerometers (EPI sensor). At least two more stations will be installed in the near future. To cope with the high resolution and dynamic of the sensors and data acquisition
Artigas, Patricio; Bargues, M Dolores; Mera y Sierra, Roberto L; Agramunt, Veronica H; Mas-Coma, Santiago
In South America, Fasciola hepatica infection poses serious health problems in both humans and livestock. In Chile, the medical impact appears yearly stable and mainly concentrated in central regions, where the veterinary problem is highlighted by higher animal prevalences. Studies were undertaken by rDNA ITS-2 and ITS-1 and mtDNA cox1 sequencing to clarify the specific status of the lymnaeids, their geographical distribution and fascioliasis transmission capacity in Chile, by comparison with other American countries and continents. Results change the lymnaeid scenario known so far. The lymnaeid fauna of mainland Chile shows to be poor, including only two authochthonous species, Lymnaea viator and Pectinidens diaphana, and a third introduced species of Palaearctic origin Galba truncatula. Both Lymnaea lebruni and Lymnaea patagonica proved to be synonyms of P. diaphana. G. truncatula appears to have always been confused with L. viator and seems distributed from Región VI to Región IX, overlapping with human endemic areas. DNA sequencing results suggest that the absence of correlation between remote sensing data and disease prevalences could be due to transmission capacity differences between L. viator and G. truncatula. Results furnish a new baseline on which to undertake future appropriate studies on transmission, epidemiology and control.
Bellanova, Piero; Bahlburg, Heinrich; Nentwig, Vanessa; Spiske, Michaela
In order to estimate the tsunami hazard it is essential to reliably identify and differentiate tsunami deposits from other high-energy events like storms. Recently, the microtextural analysis of quartz grain surfaces was introduced as a method to differentiate between tsunami and other deposits. Using tsunami deposits sampled from a bank profile of the Tirúa river (central Chile), an area that was significantly affected by the 2010 and 1960 Chile tsunamis, we tested the microtextural analysis method for its capability to identify tsunami deposits. A total of 815 quartz grain surfaces of two tsunami layers, two non-tsunami marsh sediment samples, and three reference samples from nearby beach, dune and river were analyzed using scanning electron microscopy (SEM). We grouped the detected microtexture features into five microtextural families: angularity, fresh surfaces, percussion marks, adhering particles and dissolution features. Both the tsunami deposits and reference samples reveal high numbers of fresh surfaces and percussion marks. Thus, there are no statistically significant differences between tsunami, beach, dune and river deposits in characteristics and abundances in all microtextural families. Our study indicates that the microtextural analysis of quartz grains may not be a suitable method to identify tsunami deposits in Tirúa (Chile), due to local factors such as high numbers of inherited microtextures and the possible effects of the high amount of heavy minerals.
Bravo-Vasquez, Nicolás; Karlsson, Erik A.; Jimenez-Bluhm, Pedro; Meliopoulos, Victoria; Kaplan, Bryan; Marvin, Shauna; Cortez, Valerie; Freiden, Pamela; Beck, Melinda A.
Phylogenetic analysis of the influenza hemagglutinin gene (HA) has suggested that commercial pigs in Chile harbor unique human seasonal H1-like influenza viruses, but further information, including characterization of these viruses, was unavailable. We isolated influenza virus (H1N2) from a swine in a backyard production farm in Central Chile and demonstrated that the HA gene was identical to that in a previous report. Its HA and neuraminidase genes were most similar to human H1 and N2 viruses from the early 1990s and internal segments were similar to influenza A(H1N1)pdm09 virus. The virus replicated efficiently in vitro and in vivo and transmitted in ferrets by respiratory droplet. Antigenically, it was distinct from other swine viruses. Hemagglutination inhibition analysis suggested that antibody titers to the swine Chilean H1N2 virus were decreased in persons born after 1990. Further studies are needed to characterize the potential risk to humans, as well as the ecology of influenza in swine in South America. PMID:28098524
Barrientos, S. E.
Major plans were devised in 2007 for the establishment of a new National Seismographic Network for Chile comprising the existing academic instruments together with additional instruments to be acquired. In the meantime, a network of 10 observatories has been implemented by IRIS jointly with Chilean efforts. The Government approved funding in several stages allowing the acquisition of 65 broad-band stations, 297 strong motion instruments and about 130 dual-frequency devices. The 65 broad-band sites also house accelerometers and GPS devices transmitting in robust real-time links to a Central Data Processing in Santiago. Of the 297 strong motion instruments, distributed along the country with concentrated nests in large cities, it is envisioned that only a percentage will have robust communication capabilities; the rest will be connected with 3G (or 4G) means utilizing local providers. Another suit of 60-70 GPS devices will be installed along the coast, around 40-50 km from each other covering the Chilean portion of the Nazca-South America plate interaction, considered as the most seismically active segment of the country. International collaboration efforts to include real-time transmission and processing of the GPS data will complement the existing automatic seismic system. It is expected that this complementary design will not only allow rapid preliminary estimation of hypocentral parameters but also rupture location and extension as well as displacement distribution on the causative fault, essential ingredients to assess the tsunamigenic potential of large thrust-type earthquakes in Chile.
Kohn, Robert; Rioseco, Pedro; Saldivia, Sandra; Navarrette, Gonzalo; Veloso, Paula; Torres, Silverio
Background Psychiatric epidemiological surveys in developing countries are rare and are frequently conducted in regions that are not necessarily representative of the entire country. In addition, in large countries with dispersed populations national rates may have low value for estimating the need for mental health services and programs. Methods The Chile Psychiatric Prevalence Study using the Composite International Diagnostic Interview was conducted in four distinct regions of the country on a stratified random sample of 2,978 people. Lifetime and 12-month prevalence and service utilization rates were estimated. Results Significant differences in the rates of major depressive disorder, substance abuse disorders, non-affective psychosis, and service utilization were found across the regions. The differential prevalence rates could not be accounted by socio-demographic differences between sites. Conclusions Regional differences across countries may exist that have both implications for prevalence rates and service utilization. Planning mental health services for population centers that span wide geographical areas based on studies conducted in a single region may be misleading, and may result in areas with high need being underserved. PMID:17036264
One of the most extensive Chilean health care reforms occurred in July 2005, when the Regime of Explicit Health Guarantees (AUGE) became effective. This reform guarantees coverage for a specific set of health conditions. Thus, the purpose of this study is to provide timely evidence for policy makers to understand the current distribution and equity of health care utilization in Chile. The authors analyzed secondary data from the National Socioeconomic Survey (CASEN) for the years 1992–2009 and the 2006 Satisfaction and Out-of-Pocket Payment Survey to assess equity in health care utilization using two different approaches. First, we used a two-part model to estimate factors associated with the utilization of health care. Second, we decomposed income-related inequalities in medical care use into contributions of need and non-need factors and estimated a horizontal inequity index. Findings of this empirical study include evidence of inequities in the Chilean health care system that are beneficial to the better-off. We also identified some key factors, including education and health care payment, which affect the utilization of health care services. Results of this study could help researchers and policy makers identify targets for improving equity in health care utilization and strengthening availability of health care services accordingly. PMID:23937894
Núñez, Alicia; Chi, Chunhuei
One of the most extensive Chilean health care reforms occurred in July 2005, when the Regime of Explicit Health Guarantees (AUGE) became effective. This reform guarantees coverage for a specific set of health conditions. Thus, the purpose of this study is to provide timely evidence for policy makers to understand the current distribution and equity of health care utilization in Chile.The authors analyzed secondary data from the National Socioeconomic Survey (CASEN) for the years 1992-2009 and the 2006 Satisfaction and Out-of-Pocket Payment Survey to assess equity in health care utilization using two different approaches. First, we used a two-part model to estimate factors associated with the utilization of health care. Second, we decomposed income-related inequalities in medical care use into contributions of need and non-need factors and estimated a horizontal inequity index.Findings of this empirical study include evidence of inequities in the Chilean health care system that are beneficial to the better-off. We also identified some key factors, including education and health care payment, which affect the utilization of health care services. Results of this study could help researchers and policy makers identify targets for improving equity in health care utilization and strengthening availability of health care services accordingly.
Cisternas, M.; Atwater, B.F.; Torrejon, F.; Sawai, Y.; Machuca, G.; Lagos, M.; Eipert, A.; Youlton, C.; Salgado, I.; Kamataki, T.; Shishikura, M.; Rajendran, C.P.; Malik, J.K.; Rizal, Y.; Husni, M.
It is commonly thought that the longer the time since last earthquake, the larger the next earthquake's slip will be. But this logical predictor of earthquake size, unsuccessful for large earthquakes on a strike-slip fault, fails also with the giant 1960 Chile earthquake of magnitude 9.5 (ref. 3). Although the time since the preceding earthquake spanned 123 years (refs 4, 5), the estimated slip in 1960, which occurred on a fault between the Nazca and South American tectonic plates, equalled 250-350 years' worth of the plate motion. Thus the average interval between such giant earthquakes on this fault should span several centuries. Here we present evidence that such long intervals were indeed typical of the last two millennia. We use buried soils and sand layers as records of tectonic subsidence and tsunami inundation at an estuary midway along the 1960 rupture. In these records, the 1960 earthquake ended a recurrence interval that had begun almost four centuries before, with an earthquake documented by Spanish conquistadors in 1575. Two later earthquakes, in 1737 and 1837, produced little if any subsidence or tsunami at the estuary and they therefore probably left the fault partly loaded with accumulated plate motion that the 1960 earthquake then expended. ?? 2005 Nature Publishing Group.
Cisternas, Marco; Atwater, Brian F.; Torrejón, Fernando; Sawai, Yuki; Machuca, Gonzalo; Lagos, Marcelo; Eipert, Annaliese; Youlton, Cristián; Salgado, Ignacio; Kamataki, Takanobu; Shishikura, Masanobu; Rajendran, C. P.; Malik, Javed K.; Rizal, Yan; Husni, Muhammad
It is commonly thought that the longer the time since last earthquake, the larger the next earthquake's slip will be. But this logical predictor of earthquake size, unsuccessful for large earthquakes on a strike-slip fault, fails also with the giant 1960 Chile earthquake of magnitude 9.5 (ref. 3). Although the time since the preceding earthquake spanned 123years (refs 4, 5), the estimated slip in 1960, which occurred on a fault between the Nazca and South American tectonic plates, equalled 250-350years' worth of the plate motion. Thus the average interval between such giant earthquakes on this fault should span several centuries. Here we present evidence that such long intervals were indeed typical of the last two millennia. We use buried soils and sand layers as records of tectonic subsidence and tsunami inundation at an estuary midway along the 1960 rupture. In these records, the 1960 earthquake ended a recurrence interval that had begun almost four centuries before, with an earthquake documented by Spanish conquistadors in 1575. Two later earthquakes, in 1737 and 1837, produced little if any subsidence or tsunami at the estuary and they therefore probably left the fault partly loaded with accumulated plate motion that the 1960 earthquake then expended.
Retamal C, Pedro; Markkula, Niina; Peña, Sebastián
This article analyses and compares the epidemiology of mental disorders and relevant public policies in Chile and Finland. In Chile, a specific mental health law is still lacking. While both countries highlight the role of primary care, Finland places more emphasis on participation and recovery of service users. Comprehensive mental health policies from Finland, such as a successful suicide prevention program, are presented. Both countries have similar prevalence of mental disorders, high alcohol consumption and high suicide rates. In Chile, the percentage of total disease burden due to psychiatric disorders is 13% and in Finland 14%. However, the resources to address these issues are very different. Finland spends 4.5% of its health budget on mental health, while in Chile the percentage is 2.2%. This results in differences in human resources and service provision. Finland has five times more psychiatric outpatient visits, four times more psychiatrists, triple antidepressant use and twice more clinical guidelines for different psychiatric conditions. In conclusion, both countries have similar challenges but differing realities. This may help to identify gaps and potential solutions for public health challenges in Chile. Finlands experience demonstrates the importance of political will and long-term vision in the construction of mental health policies.
... TRADE COMMISSION Preserved Mushrooms from Chile, China, India, and Indonesia AGENCY: United States... duty orders on preserved mushrooms from Chile, China, India, and Indonesia. SUMMARY: The Commission... orders on preserved mushrooms from Chile, China, India, and Indonesia would be likely to lead...
... International Trade Administration Certain Preserved Mushrooms From Chile, India, Indonesia, and the People's... antidumping duty orders on certain preserved mushrooms (mushrooms) from Chile, India, Indonesia, and the... reviews of the antidumping duty orders on mushrooms from Chile, India, Indonesia, and the PRC, pursuant...
... Chile. 10.490 Section 10.490 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND... States-Chile Free Trade Agreement Goods Returned After Repair Or Alteration § 10.490 Goods re-entered after repair or alteration in Chile. (a) General. This section sets forth the rules which apply...
Davis, Sally M.; Sanders, Sarah G.; FitzGerald, Courtney A.; Keane, Patricia C.; Canaca, Glenda F.; Volker-Rector, Renee
Background: Obesity is a major concern among American Indians and Hispanics. The Child Health Initiative for Lifelong Eating and Exercise (CHILE) is an evidence-based intervention to prevent obesity in children enrolled in 16 Head Start (HS) Centers in rural communities. The design and implementation of CHILE are described. Methods: CHILE uses a…
... COMMISSION Actual Effects of the Free Trade Agreements With Chile, Australia, and Singapore AGENCY: United...) instituted investigation No. 332-515, Actual Effects of the Free Trade Agreements with Chile, Australia, and...) concluded with Chile, Singapore, and Australia. In its report the Commission will-- (1) With respect to...
Farrell, T.A.; Marion, J.L.
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.
Schnettler, Berta; Denegri, Marianela; Miranda, Horacio; Sepúlveda, José; Orellana, Ligia; Paiva, Galo; Grunert, Klaus G
Objetivo: Distinguir tipologías de estudiantes universitarios en el sur de Chile, en base a su nivel de satisfacción con la vida y la alimentación, y caracterizarlas según sus hábitos alimentarios dentro y fuera del lugar de residencia, aspectos asociados a la salud y características demográficas. Material y método: Se aplicó un cuestionario estructurado a una muestra no probabilística de 347 estudiantes de la Universidad de La Frontera, Temuco-Chile. El instrumento de recogida de información incluyó las escalas SWLS (Satisfaction with Life Scale), SWFL (Satisfaction with Food-related Life) y el ICVRS (Índice de calidad de vida relativo a la salud). Se consultaron los hábitos de consumo de alimentos dentro y fuera del lugar de residencia, el peso y estatura aproximada y, variables de clasificación demográfica. Resultados: Mediante análisis clúster se distinguieron tres tipologías de estudiantes con diferencias significativas en los puntajes de la SWLS y SWFL. Las tipologías difirieron en el número de días afectados por problemas de salud emocional, clasificación de su estado nutricional (IMC), auto percepción de su estado de salud, importancia de la alimentación para el bienestar personal, lugar de residencia durante el periodo de estudios, frecuencia de alimentación en el lugar donde vive y frecuencia de comidas a deshora. Conclusiones: La posibilidad de vivir con los padres durante el periodo de estudios universitarios se asocia con mejores hábitos de alimentación, mejor salud emocional y auto percepción de la salud, menor prevalencia de sobre peso y obesidad y, con una mayor satisfacción con la vida y la alimentación.
Carn, Simon A.; Pallister, John S.; Lara, Luis; Ewert, John W.; Watt, Sebastian; Prata, Alfred J.; Thomas, Ronald J.; Villarosa, Gustavo
On 2 May 2008, a large eruption began unexpectedly at the inconspicuous Chaitén volcano in Chile's southern volcanic zone. Ash columns abruptly jetted from the volcano into the stratosphere, followed by lava dome effusion and continuous low-altitude ash plumes [Lara, 2009]. Apocalyptic photographs of eruption plumes suffused with lightning were circulated globally. Effects of the eruption were extensive. Floods and lahars inundated the town of Chaitén, and its 4625 residents were evacuated. Widespread ashfall and drifting ash clouds closed regional airports and cancelled hundreds of domestic flights in Argentina and Chile and numerous international flights [Guffanti et al., 2008]. Ash heavily affected the aquaculture industry in the nearby Gulf of Corcovado, curtailed ecotourism, and closed regional nature preserves. To better prepare for future eruptions, the Chilean government has boosted support for monitoring and hazard mitigation at Chaitén and at 42 other highly hazardous, active volcanoes in Chile.
Carn, Simon A.; Zogorski, John S.; Lara, Luis; Ewert, John W.; Watt, Sebastian; Prata, Alfred J.; Thomas, Ronald J.; Villarosa, Gustavo
On 2 May 2008, a large eruption began unexpectedly at the inconspicuous Chaitén volcano in Chile's southern volcanic zone. Ash columns abruptly jetted from the volcano into the stratosphere, followed by lava dome effusion and continuous low-altitude ash plumes [Lara, 2009]. Apocalyptic photographs of eruption plumes suffused with lightning were circulated globally. Effects of the eruption were extensive. Floods and lahars inundated the town of Chaitén, and its 4625 residents were evacuated. Widespread ashfall and drifting ash clouds closed regional airports and cancelled hundreds of domestic flights in Argentina and Chile and numerous international flights [Guffanti et al., 2008]. Ash heavily affected the aquaculture industry in the nearby Gulf of Corcovado, curtailed ecotourism, and closed regional nature preserves. To better prepare for future eruptions, the Chilean government has boosted support for monitoring and hazard mitigation at Chaitén and at 42 other highly hazardous, active volcanoes in Chile.
Toscanini, Ulises; Moreno, Fabián; Pantoja-Astudillo, Jaime A; Morales, Eugenia Aguirre; Bustos, Patricio; Salas, Antonio
We estimated the allele frequencies for the 15 autosomal STR loci included in the AmpFlSTR(®) Identifiler (Applied Biosystems, USA) in a sample of 986 unrelated non-Native American individuals collected at five different localities from Chile, namely, Iquique, Santiago, Concepción, Temuco and Punta Arenas. Frequency distributions and several forensic parameters were estimated at each recruitment site. In addition, analyses were carried out merging the data into five sample locations. No significant statistical differences could be detected between different regions in Chile. These data represent one of the very few studies performed on autosomal STRs in Chile and therefore provide a useful tool for forensic casework carried out in the country.
Soto, Leopoldo; Zambra, Marcelo; Loewe, Marcelo; Gutiérrez, Gonzalo; Molina, Mario; Barra, Felipe; Lund, Fernando; Saavedra, Carlos; Haberle, Patricio
In the present work, an assessment of the Physics research capacity in Chile is presented. For this, the period between 2000 and June 2005 has been studied. In this period almost 200 physicists have contributed to scientific production in terms of ISI publications. Amongst these 200, ~160 correspond to theoretical physicists and only ~40 to experimental physicists; ~178 are men and only ~22 are women. A more detailed analysis shows that ~160 physicists have at least one appearance in ISI publications per year considering the last 3 years. Ten years ago, a similar criteria (at least one appearance per year in ISI articles, considering mobile three-year periods), the number of active physicists in the Chilean community was estimated at 70. Therefore, the Chilean active physicists' community has doubled in 10 years. There exist 20 centres in which scientific research is developed: 18 university centres, a government institute and a private institute. As regards scientific productivity, both as related to disciplines or research areas, and well as in relation to research centres, it is found that, generally, scientific production, in a particular area in Physics or in a research centre, is directly related to the number of corresponding researchers; that is to say, the percentage of the national productivity in an area or research centre corresponds to its share in the total number of physicists in the country. A geographical analysis shows that 50% of the productivity corresponds to Santiago and 50% to the rest of the country. The impact of the different funds for research is assessed, also: FONDECYT, Presidential Chairs and large projects and centres of excellence. According to Physics researchers opinion, Fondo Nacional de Ciencia y Tecnología (FONDECYT, National Fund fro Science and Technology) has become the best instrument to support researchi activities in Chile. However, the amount of projects awarded has practically not been increased, which is insufficient
Minson, S. E.; Simons, M.; Owen, S.; Genrich, J.; Galetzka, J.; Chowdhury, F. R.; Webb, F.; Beck, J. L.; Comte, D.; Glass, B.; Leiva, C.
The magnitude 7.7 Tocopilla earthquake of November 14, 2007 ruptured a stretch of the northern Chile subduction zone just north of the 1995 Antofagasta earthquake source region. In this study, we compare a Bayesian analysis with a simulated annealing inversion methodology to determine a finite fault rupture model for the Tocopilla earthquake. While we also incorporate both teleseismic data and satellite radar images, high-rate (5 samples/sec) GPS data provides particularly important constraints on the source process of this event. Because the Tocopilla earthquake was located immediately coastward of the CANTO (Central ANdean Tectonic Observatory) geodetic network, the evolution of the local slip field is well-recorded. We find that the high-rate continuous GPS data is key to determining the location of the hypocenter and asperities as well as the evolution of slip. Most of the slip is located east of the coastline with at least two distinct regions of concentrated slip.
Venzal, José M; Nava, Santiago; González-Acuña, Daniel; Mangold, Atilio J; Muñoz-Leal, Sebastián; Lado, Paula; Guglielmone, Alberto A
A new species, Ornithodoros microlophi (Acari: Argasidae), belonging to the subgenus Alectorobius is described from larvae collected on the lizards Microlophus atacamensis (Donoso-Barros, 1966) and Microlophus quadrivittatus (Tschudi, 1845) (Squamata: Tropiduridae) in continental and insular localities from northern Chile. Larvae of O. microlophi can be distinguished from other Neotropical species of the genus Ornithodoros by a combination of the following characters, namely 10 pairs of ventral setae, venter with 6 pairs of sternal setae, dorsal plate pyriform, 19-21 pairs of dorsal setae (typically 20), 13 pairs are dorsolateral and 7 pairs are central, and hypostome with dental formula 4/4 in medial portion and apex pointed. Phylogenetic analysis of 16S rDNA sequences suggests that O. microlophi represents an independent lineage within Neotropical species of the Argasidae.
Rubio, María A; Zamorano, Natalia; Lissi, Eduardo; Rojas, Alicia; Gutiérrez, Luis; von Baer, Dietrich
Formaldehyde, acetaldehyde, acetone, propanal, butanal, 2-butenal, 3-methylbutanal, hexanal, benzaldehyde, 2-methylbenzaldehyde, and 2,5-dimethylbenzaldehyde were measured during six spring days at downtown Santiago de Chile. Measurements were performed 24h/day and averaged over three hour periods. The averages of the maxima (ppbv) were, formaldehyde: 3.9+/-1.4; butanal: 3.3+/-3.4; acetaldehyde: 3.0+/-0.9; acetone: 2.4+/-1.0; 2-butenal: 0.56+/-0.52; propanal: 0.46+/-0.21; benzaldehyde: 0.34+/-0.3; 3-butanal: 0.11+/-0.05; hexanal: 0.11+/-0.08; 2-methylbenzaldehyde: 0.08+/-0.05; 2,5-dimethylbenzaldehyde: 0.05+/-0.03. Aliphatic aldehydes (C1-C3) are strongly correlated among them and weakly with primary (toluene) and secondary (ozone plus nitrogen dioxide or PAN) pollutants. In particular, the correlation between acetaldehyde and propanal values remains even if diurnal and nocturnal data are considered separately, indicating similar sources. All these aldehydes present maxima values in the morning (9-12h) and minima at night (0-3h). The best correlation is observed when butanal and 2-butenal data are considered (r=0.99, butanal/2-butenal=6.2). These compounds present maxima values during the 3-6h period, with minima values in the 0-3h period. These data imply a strong pre-dawn emission. Other aldehydes show different daily profiles, suggesting unrelated origins. Formaldehyde is the aldehyde whose concentration values best correlate with the levels of oxidants. The contribution of primary emissions and photochemical processes to formaldehyde concentrations were estimated by using a multiple regression. This treatment indicates that (32+/-16)% of measured values arise from direct emissions, while (79+/-23)% is attributable to secondary formation.
In the context of a festschrift to commemorate the 125th anniversary of the Revista Médica de Chile, "radiography" of the journal has been depicted using several scientometric indicators. Among the mainstream journals in the category of Medicine, General & Internal and taking into account the wide editorial coverage and the language of the publication that fulfills the need for the required social appropriation of science that the country requires, the Revista Médica de Chile portrays healthy and quite relevant. Among the articles published between 1981 and 1995, some concerning public health have reached, particularly, an impact which surpasses their mean expected citation rate.
Bennett, K D; Haberle, S G; Lumley, S H
Warming at the last glacial termination in the North Atlantic region was interrupted by a period of renewed glacial activity during the Younger Dryas chronozone (YDC). The underlying mechanism of this cooling remains elusive, but hypotheses turn on whether it was a global or a North Atlantic phenomenon. Chronological, sedimentological, and palaeoecological records from sediments of small lakes in oceanic southern Chile demonstrate that there was no YDC cooling in southern Chile. It is therefore likely that there was little or no cooling in southern Pacific surface waters and hence that YDC cooling in the North Atlantic was a regional, rather than global, phenomenon.
Situación terremoto zona centro sur (Actualiza reporte),” March 1, 2010; Hillary Rodham Clinton, “Remarks With Chilean President Michelle Bachelet...U.S. Department of State, March 2, 2010. 6 “Bachelet decreta primer Estado de Catástrofe desde terremoto de 1985,” El Mercurio (Chile), March 1...2010; “Amplían toque de queda en zonas más afectadas por terremoto en Chile,” Agence France Presse, March 1, 2010; “160 detained, one killed during
Lizana, Pablo A; Simpson, Cristina; Yáñez, Lily; Saavedra, Karime
Introducción: La obesidad en niños es un problema multifactorial, entre ellos se encuentra la percepción que tienen de su propio peso. Objetivo: Determinar la concordancia entre el estado nutricional percibido y el real en escolares de áreas rurales. Métodos: Comprenden 206 estudiantes de primer a octavo año de enseñanza primaria de establecimientos rurales de la región de Valparaíso, Chile (43% mujeres). El estado nutricional real se evaluó a través del índice de masa corporal (IMC) y la percibida mediante figuras corporales. El nivel socioeconómico (NSE) se determinó mediante la escala de Graffar modificada. Los análisis se realizaron utilizando el coeficiente de concordancia kappa y para la asociación de variables se utilizó la prueba X2. Resultados: Los sujetos se concentran en el NSE bajo (82% hombres; 72% mujeres). 49.5% de los escolares presenta sobrepeso y obesidad. Los hombres presentan una mayor prevalencia de obesidad (29%) que las mujeres (20%). El 62,5% de las mujeres subestiman su peso, cifra mayor que en el caso de los hombres (52,5%). El 98,10% de los individuos obesos subestiman su peso y el 100% de los niños estudiados en condición de sobrepeso también lo subestiman. Conclusiones: Los niños y niñas de contextos rurales en condición de sobrepeso y obesidad son los que presentan la mayor prevalencia de una inadecuada percepción de la imagen corporal (subestimación) lo cual tiene un importante impacto al no reconocer su condición de malnutrición por exceso. Esta condición puede tener importantes repercusiones en salud pública, puesto que esta condición se puede mantener hasta la vida adulta, desarrollando enfermedades crónicas no transmisibles.
Bevins, R. E.; Robinson, D.; Aguirre, L.; Vergara, M.
The Central Andes of Chile are characterized by subgreenschist facies burial metamorphism that is reported as having developed in up to seven episodic cycles of some 40Myr duration. The main evidence in support of the model is reported as mineralogical breaks at major stratigraphic boundaries that are interpreted as documenting sharp breaks in metamorphic grade. Here we test this model by examination of the progressive secondary mineral development, reaction progress in mafic phyllosilicates, and topological variations of the low-grade assemblages in metabasites for Jurassic to Miocene sequences east of Santiago. The mafic phyllosilicates (smectite - mixed-layer chlorite/smectite - chlorite) show increasing reaction progress with stratigraphic age and there is a continuum across the main stratigraphic boundaries, such there is no offset or gap in the reaction progress at these boundaries. There are some differences in mineral assemblages between the various stratigraphic units, such as between prehnite+pumpellyite+/-laumonite or amphibole-bearing and non amphibole bearing rocks, from which contrasting subgreenschist facies can be recognised. However, consideration of the controls on mineral parageneses at subgreenschist facies conditions demonstrates that these different facies cannot be used solely as evidence of sharp breaks in metamorphic grade at unconformities, as has been reported in many previous publications for the Andes. The presently accepted model for the Central Andes, involving repeated cycles of episodic metamorphism developing in extensional basins, is, therefore, partly unfounded. Consideration of the overall tectonic evolution of this part of the Andes concurs that the burial metamorphism developed in extensional settings, but in only two events, namely in mid-late Cretaceous and Late Miocene times respectively. The results from this work suggest that the record of sharp metamorphic breaks and the episodic model of metamorphism reported for many
Schurr, Bernd; Asch, Günter; Cailleau, Beatrice; Diaz, Guillermo Chong; Barrientos, Sergio; Vilotte, Jean-Pierre; Oncken, Onno
The oceanic Nazca plate subducts beneath the continental South American plate by recurrent rupture of large segments of its interface. The resulting earthquakes are among the largest and most frequent on Earth. Along the Chilean and southern Peruvian margin, all sizeable segments have ruptured at least once in the past 150 years for which there exist historic and/or instrumental records. The one segment that is most mature for re-rupture stretches for more than 500 km along the northernmost Chilean coast between roughly -23° and -18° latitude. It last broke in 1877 in a magnitude ~8.5 earthquake, triggering a major Tsunami. From the historical record, it has been known to have a recurrence cycle of approximately 110 years. The adjoining segments to the south and north broke rather recently in 1995 and 2001 in M>8 earthquakes and an M 7.7 earthquake intruded into the southern part of the seismic gap in 2007 between Antofagasto and Tocopilla. This makes northern Chile a unique natural laboratory to observe a subduction megathrust at various stages of its seismic cycle. For that purpose, installation of long-term observatories started in 2006 in a close cooperation of the Universidad de Chile (Santiago, Chile), the Universidad Catolica del Norte (Antofagasta, Chile), the Institut de Physique du Globe de Paris (France), and the GFZ German research Centre for Geosciences (Germany). Currently we are operating 17 modern seismological stations equipped with STS-2 broadband seismometers and accelerometers (EPI sensor). At least two more stations will be installed in the near future. Continuous GPS, tilt, creep, climate and magnetotellurics measurements are complementing the seismological part. A majority of the sites provide data near real-time. We will present results of seismic monitoring including analysis of the 2007 M7.7 Tocopilla earthquake sequence that was recorded during the installation stage of the observatory. We relocated the mainshock and about a one
Arias, Elizabeth T.
Bohartina Arias, a new genus of Elateridae from forests in the Andean Cordillera of Central Chile, is here described and illustrated with 2 species: B. vilchesensis sp. nov. and B. palmae sp. nov. The genus Bohartina belongs to the subfamily Elaterinae and to the tribe Agriotini. PMID:19537982
Bown, Francisca; Rivera, Andrés; Acuña, César
The majority of glaciers in central Chile have receded in recent decades, from >50 m to only a few meters per year, mainly in response to an increase in the 0°C isotherm altitude. The Aconcagua river basin (33° S) is one of the major glaciated basins in central Chile, with 121 km2 of ice in 2003. An earlier inventory using 1955 aerial photographs yielded a total surface area of 151 km2, implying a reduction in glacier area of 20% (0.63 km2 a-1) over the 48 years. Photographic stereo models, high-resolution satellite images (Landsat, ASTER) and SRTM data have been used to delineate glacier basins. A focus on Glaciar Juncal Norte, one of the largest glaciers in the basin, allows a more detailed analysis of changes. The glacier has exhibited a smaller reduction (14%) between 1955 and 2006, and the resulting elevation changes over this smaller period are not significant. The above reduction rates are lower than in other glaciers of central Chile and Argentina. This trend emphasizes water runoff availability in a river where most of the water in the dry summers is generated by glaciers and snowpack, and where most of the superficial water rights are already allocated. Ongoing hydrological research including modelling of future water runoff will improve our understanding.
Garth, Thomas; Rietbrock, Andreas
Guided wave dispersion is observed in subduction zones as high frequency energy is retained and delayed by low velocity structure in the subducting slab, while lower frequency energy is able to travel at the faster velocities associated with the surrounding mantle material. As subduction zone guided waves spend longer interacting with the low velocity structure of the slab than any other seismic phase, they have a unique capability to resolve these low velocity structures. In Northern Chile, guided wave arrivals are clearly observed on two stations in the Chilean fore-arc on permanent stations of the IPOC network. High frequency (> 5 Hz) P-wave arrivals are delayed by approximately 2 seconds compared to the low frequency (< 2 Hz) P-wave arrivals. Full waveform finite difference modelling is used to test the low velocity slab structure that cause this P-wave dispersion. The synthetic waveforms produced by these models are compared to the recorded waveforms. Spectrograms are used to compare the relative arrival times of different frequencies, while the velocity spectra is used to constrain the relative amplitude of the arrivals. Constraining the waveform in these two ways means that the full waveform is also matched, and the low pass filtered observed and synthetic waveforms can be compared. A combined misfit between synthetic and observed waveforms is then calculated following Garth & Rietbrock (2014). Based on this misfit criterion we constrain the velocity model by using a grid search approach. Modelling the guided wave arrivals suggest that the observed dispersion cannot be solely accounted for by a single low velocity layer as suggested by previous guided wave studies. Including dipping low velocity normal fault structures in the synthetic model not only accounts for the observed strong P-wave coda, but also produces a clear first motion dispersion. We therefore propose that the lithospheric mantle of the subducting Nazca plate is highly hydrated at intermediate
Sanchez, Jaime; Salinas, Alvaro; Harris, Jordan
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…
Aedo-Richmond, Ruth; Richmond, Mark
Reports on curriculum reform in Chile following the 1990 replacement of the Pinochet military regime with the democratically elected government of Patricio Aylwin. Significant reforms occurred in primary and rural education. Other improvements included increased professionalization of teaching, and funding for the Ministry of Education. (MJP)
Carrasco, Alejandro; Fromm, Germán
Chile is well known worldwide for its extensive use of market-driven mechanisms in education. Using a case study strategy in three schools, this paper shows that "universal" voucher system and mixed provision (co-existence of subsidised private and state-funded schools) policies are reshaping school management practices. The paper draws…
One of the larger of the native peoples of South America, the Araucanians include different ethnic subgroups, some of which are now extinct. Once geographically spread extensively over the southern cone of South America, at present they are reduced to only two closely related groups: (1) the Mapuche of southern Chile, the largest one; and (2) the…
Zhu, Xiao-San; Lu, Min-Jie
Chile is a very important country that forms part of the Andean metallogenic belts. The Atacama and Domeyko fault systems in northern Chile control the tectonic-magmatic activities that migrate eastward and the types of mineral resources. In this paper, we processed and interpreted aeromagnetic data from northern Chile using reduction to pole, upward field continuation, the second derivative calculation in the vertical direction, inclination angle calculation, and analytical signal amplitude analysis. We revealed the locations and planar distribution characteristics of the regional deep faults along the NNE and NS directions. Furthermore, we observed that the major reasons for the formation of the tectonic-magmatic rocks belts were the nearly parallel deep faults distributed from west to east and multiple magmatic activities along these faults. We ascertained the locations of volcanic mechanisms and the relationships between them using these regional deep faults. We deduced the spatial distributions of the basic-intermediate, basic, and acidic igneous rocks, intrusive rocks, and sedimentary sequences. We showed the linear positive magnetic anomalies and magnetic anomaly gradient zones by slowly varying the background, negative magnetic anomaly field, which indicated the presence of strong magmatic activities in these regional deep faults; it also revealed the favorable areas of copper and polymetallic mineralization. This study provides some basic information for further research on the geology, structural characteristics, and mineral resource prospecting in northern Chile.
Larrain, Christian; Zurita, Salvador
Chile's higher education system stands out as being one of the most privatized and open to the market in the world. Recently, the Chilean Congress passed Law #20.027 of 2005, which provides the legal framework for the creation of a student loan system guaranteed both by the State and by higher education institutions (HEIs), financed by the private…
Many of the most primitive Neotropical bush katydids (Phaneropterinae) — including species of Cosmophyllum Blanchard, Stenophylla Brunner von Wattenwyl, Marenestha Brunner von Wattenwyl, Anisophya Karabag, Coryphoda Brunner von Wattenwyl, and Burgilis Stål — are endemic in Chile. The Chilean species...
Malloy, Jacquelynn A., Comp.; Botzakis, Stergios, Comp.
This is a compilation of reports on international literacy research. The report includes 4 separate reports on Chile, Argentina, Brazil, and Colombia. In the first report, research correspondent Marta Infante reports on two studies that reflect the growing interest of Chilean professionals in studying reading-related factors such as phonemic…
McEwan, Patrick J.
Chile operates one of the oldest and largest school feeding programs in Latin America, targeting higher-calorie meals to relatively poorer schools. This paper evaluates the impact of higher-calorie meals on the education outcomes of public, rural schools and their students. It applies a regression-discontinuity design to administrative data,…
1994.21 Nonetheless, Mapuche communities maintain that land transfers have been slow and represent only a fraction of their ancestral territory .22 As a... Conflicto Mapuche Preocupa Pero No Hay Una ‘Guerra Civil’, Según Gobierno,” EFE News Service, October 21, 2009. 24 “Chile Arrests Mapuche Militant
Ceballo, Rosario; Ramirez, Cynthia; Castillo, Marcela; Caballero, Gabriela Alejandra; Lozoff, Betsy
Domestic violence against women is a pervasive, global health problem. This study investigates the correlates and psychological outcomes of domestic abuse among women in a semi-industrial country. The participants included 215 mothers residing in working-class communities located on the outskirts of Santiago, Chile. We utilized structural equation…
Espinoza, Oscar; Gonzalez, Luis Eduardo
Purpose: The purpose of this paper is to analyze and discuss the results that the accreditation system implemented in Chile has brought to higher education institutions and undergraduate and graduate programs, taking into account both its positive and negative implications. Design/methodology/approach: The examination of the Chilean accreditation…
access to education. Despite these actions, some Chileans felt more radical change was needed. In 1970 , Salvador Allende, a Socialist and the leader of...Chile: Country Report,” Economist Intelligence Unit, December 2008. 32 Eva Vergara, “Bachelet Crea Comisión para Enfrenter Desempleo por Crisis
The paper focuses on the growth and development of special education for learning disabled children in Chile with particular emphasis on the contribution of child psychiatry and pediatric neurology departments of hospitals and the contribution of universities in training specialists. Initial sections provide a background on primary education in…
Donoso, Patricio; Gajardo, Marcela
This document contains two case studies of adult education programs in Chile. Both case studies begin with a "face sheet" on which is recorded basic information about the program and the description. The first case study, prepared by Patricio Donoso, reports on Centro El Canelo de Nos, an inservice center for educators who work with…
... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION The Chile Fund, Inc.; Notice of Application March 8, 2010. AGENCY: Securities and Exchange... Company Act of 1940 (the ``Act'') for an exemption from section 17(a) of the Act. Applicant: The...
The aim of this study was to explore the different ways in which a number of Chilean stakeholders conceptualise the "good early childhood educator" in Chile. In a context where new foreign narratives are increasingly dominating the field and the recent standardisation of the educators' professional role is being implemented, this…
This article examines the major consequences of the neoliberal education system implemented in Chile during the dictatorship of Augusto Pinochet and how two important student movements contested this structure. In 2006 and 2011, thousands of students filled the streets to demand better public education, more social justice and equal opportunities.…
Espinoza, Manuel Antonio; Cabieses, Báltica; Paraje, Guillermo
Health research is considered an essential element for the improvement of population health and it has been recommended that a share of the national health budget should be allocated to develop this field. Chile has undertaken efforts in the last decades in order to improve the governmental structure created to promote the development of health research, which has increased human resources and funding opportunities. On the other hand, the sustained economic growth of Chile in the last decades suggests that the health expenditure will maintain its increasing trend in the following years. This additional funding could be used to improve coverage of current activities performed in the health system, but also to address the incorporation of new strategies. More recently, health technology assessment (HTA) has been proposed as a process to support decisions about allocation of resources based on scientific evidence. This paper examines the relationship between the development of health research and the HTA process. First, it presents a brief diagnosis of the situation of health research in Chile. Second, it reviews the conceptual basis and the methods that account for the relationship between a HTA process and the development of health research. In particular, it emphasizes the relevance of identifying information gaps where funding additional research can be considered a good use of public resources. Finally, it discusses the challenges and possible courses of action that Chile could take in order to guarantee the continuous improvement of an articulated structure for health research and HTA.
Godoy, Marcos G; Aedo, Alejandra; Kibenge, Molly JT; Groman, David B; Yason, Carmencita V; Grothusen, Horts; Lisperguer, Angelica; Calbucura, Marlene; Avendaño, Fernando; Imilán, Marcelo; Jarpa, Miguel; Kibenge, Frederick SB
Background Infectious salmon anaemia (ISA) is a viral disease of marine-farmed Atlantic salmon (Salmo salar) caused by ISA virus (ISAV), which belongs to the genus Isavirus, family Orthomyxoviridae. The virus is considered to be carried by marine wild fish and for over 25 years has caused major disease outbreaks in marine-farmed Atlantic salmon in the Northern hemisphere. In the Southern hemisphere, ISAV was first detected in Chile in 1999 in marine-farmed Coho salmon (Oncorhynchus kisutch). In contrast to the classical presentation of ISA in Atlantic salmon, the presence of ISAV in Chile until now has only been associated with a clinical condition called Icterus Syndrome in Coho salmon and virus isolation has not always been possible. During the winter of 2007, unexplained mortalities were registered in market-size Atlantic salmon in a grow-out site located in Chiloé in Region X of Chile. We report here the diagnostic findings of the first significant clinical outbreak of ISA in marine-farmed Atlantic salmon in Chile and the first characterization of the ISAV isolated from the affected fish. Results In mid-June 2007, an Atlantic salmon marine farm site located in central Chiloé Island in Region X of Chile registered a sudden increase in mortality following recovery from an outbreak of Pisciricketsiosis, which rose to a cumulative mortality of 13.6% by harvest time. Based on the clinical signs and lesions in the affected fish, and laboratory tests performed on the fish tissues, a confirmatory diagnosis of ISA was made; the first time ISA in its classical presentation and for the first time affecting farmed Atlantic salmon in Chile. Rapid sequencing of the virus-specific RT-PCR products amplified from the fish tissues identified the virus to belong to the European genotype (Genotype I) of the highly polymorphic region (HPR) group HPR 7b, but with an 11-amino acid insert in the fusion glycoprotein, and ability to cause cytopathic effects (CPE) in CHSE-214 cell line
Rios, M; Fernandez, J; Jaramillo, P; Paredes, V; Sanchez, J L; Laguna-Torres, V A; Carr, J K; Ramirez, E
We examined the genetic makeup of 221 HIV-1 strains from Chilean persons living with HIV/AIDS by HMA and DNA sequencing of the env gene: 143 cases were infected by sexual contact with an already-infected partner, 76 were infected by mother-to-child transmission, and 2 were transfusion related. We found env HIV-1 subtype B in 202 cases (91.4%) and subtype F in 19 cases (8.6%). Subtype B strains were found throughout the country whereas subtype F viruses were predominantly found in cases from the metropolitan/central to the northern regions of Chile (p < 0.01). Chilean F subtypes clustered in two different groups: viruses from the central region clustered with F subtypes from Argentina, Uruguay, and Brazil, and viruses from the northern region, which independently segregated from other South American and European F strains. All of the 59 men having sex with men (MSM) were infected with B subtype strains whereas 7 (9.2%) and 12 (15.8%), respectively, of heterosexually infected females and children were infected with F subtype strains (p < 0.01). It appears that F subtype strains have been introduced into Chile by separate heterosexual transmission events from other nearby countries in the Southern Cone whereas B subtype strains have continued to persist predominantly among MSM.
... infection; CVC - infection; Central venous device - infection; Infection control - central line infection; Nosocomial infection - central line infection; Hospital acquired infection - central line infection; Patient safety - central ...
Hertzberg, Ruth A.
This paper describes the lives of some notable women in the history of Chile from the time of the conquistadors to the present. The significant women described in the paper include: (1) Ines de Suarez (accompanied Pedro de Validivia in 1544); (2) Micaela Bastidas Puyucahua (wife of Incan leader Jose Gabriel Tupac Amaru, about 1780); (3) Gabriela…
Lamy, F.; Hebbeln, D.; Kaiser, J.; Mohtadi, M.; Ninnemann, U.
A combined analysis of terrigenous and biogenic compounds in marine sediments from the Chilean continental margin allows detailed reconstructions of the paleoclimatic and paleoceanographic history of this region during the last ca. 120,000 years. Based on several sediment cores recovered during two German cruises and ODP Leg 202 (Site 1233), 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 and salinity 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 for example generally more humid conditions during the LGM 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. North of 33°S, these general productivity patterns are complicated by additional impacts from the tropics resulting in maximum paleoproductivity during the deglaciation and prior to the LGM. On shorter time-scales, extremely high resolution sediment cores from the southern Chilean margin provide evidence of significant short-term Holocene climate variability with bands of variability centred at ca. 900 and 1500 years, periodicities also well known from Northern Hemisphere records. Recently drilled ODP Site 1233 allowed to prolong these records into the last glacial. The available data show millennial-scale SST changes that closely follow the temperature pattern known from Antarctic ice-cores. Including other records from the Southern Hemisphere mid-latitudes, our data suggest a quasi-hemisphere-wide response that is consistent with the
Michel, J.; Baumgartner, L.; Cosca, M.; Ovtcharova, M.; Putlitz, B.; Schaltegger, U.
The upper crustal bimodal Torres del Paine Intrusion, southern Chile, consists of the lower Paine-Mafic- Complex and the upper Paine-Granite. Geochronologically this bimodal complex is not well studied except for a few existing data from Halpern (1973) and Sanchez (2006). The aim of this study is to supplement the existing data and to constrain the age relations between the major magmatic pulses by applying high precision U-Pb dating on accessory zircons and 40Ar/39Ar-laser-step-heating-ages on biotites from the Torres del Paine Intrusion. The magmatic rocks from mafic complex are fine to medium-grained and vary in composition from quartz- monzonites to granodiorites and gabbros. Coarse-grained olivine gabbros have intruded these rocks in the west. The granitic body is represented by a peraluminous, biotite-orthoclase-granite and a more evolved leucocratic granite in the outer parts towards the host-rock. Field observations suggest a feeder-zone for the granite in the west and that the granite postdates the mafic complex. Two granite samples of the outermost margins in the Northeast and South were analyzed. The zircons were dated by precise isotope-dilution U-Pb techniques of chemically abraded single grains. The data are concordant within the analytical error and define weighted mean 206/238U ages of 12.59 ± 0.03 Ma and 12.58 ± 0.01 Ma for the two samples respectively. A 40Ar/39Ar-age for the second sample yield a date of 12.37 ± 0.11 Ma. Three 40Ar/39Ar -ages of biotites were obtained for rocks belonging to the mafic complex. A hbl-bio- granodiorite from the central part, approximately 150 m below the subhorizontal contact with the granite, gives an age of 12.81 ± 0.11 Ma. A hbl-bio-granodiorite and an olivine-gabbro west of the feeder-zone date at 12.42 ± 0.14 Ma and 12.49 ± 0.11 Ma, respectively. The obtained older age of 12.81 Ma for the granodiorite in the central part is consistent with structural relationships of brittle fracturing of the mafic
Díaz, Pablo E; Muñoz, Gabriela; George-Nascimento, Mario
A new species, Hemipera cribbi sp. nov., is described. This trematode was found in three intertidal fish species: Scartichthys viridis (Valenciennes) (Blenniidae), Gobiesox marmoratus Jenyns (Gobiesocidae) and Myxodes viridis Valenciennes (Clinidae) from the central and southern coast of Chile. Of 233 individuals of S. viridis from the central coast examined, 19 were infected. From the southern coast, nine individuals of S. viridis (one infected), five individuals of G. marmoratus (four infected), and 16 individuals of M. viridis (one fish infected) were examined. Hemipera cribbi sp. nov. is distinguished from the five other congeneric species mainly in the body size, being the smallest and narrowest species in the genus, reaching five times longer than wide. This is the first species of the genus described for the South Pacific Ocean off South America. ITS2 rDNA sequences of Hemipera cribbi sp. nov. from each host and locality were identified.
Bustamante-Ortega, Ramon; Morgenstern, Uwe; Ramirez de Arellano, Pablo
Water quantity and quality response of forest catchments to climate and land-use change are difficult to understand and predict due to complexities of subsurface water flow paths. The main focus of forest hydrology in Chile has been the effect of canopy and soil together with rain in water availability. Groundwater, as a factor in water availability especially during dry season, has not been studied. Only a few studies have been carried out in northern Chile in a non-forestry area using the stable isotopes of the water to characterize recharge and depletion of the aquifer. We use tritium for understanding the dynamics of groundwater through small watersheds over a latitudinal gradient in the coastal range of Central Chile. The zone constitutes rapid growth plantations and a large population that depend on surface water and groundwater for drinking, agriculture, pasture and industry. The study areas have metamorphic bedrock with a Mediterranean weather, and precipitation ranging from 700-800 mm year-1 in the North (Constitución area) to 2300-2500 mm year-1 in the South (Valdivia area). The watersheds have been forested with Pinus radiata in 2003 and 1990 respectively, and flow stations were installed in 2008 by Forestal Arauco S.A. to identify the forest management impact on the water cycle. Tritium is present in meteoric water and decays through radioactive decay. In groundwater, which is separated from the tritium production source in the atmosphere, the tritium concentration decreases over time and therefore allows for determination of the residence time of the water in the groundwater system, and the lag time between recharge of the water, and discharge into the streams. Preliminary results of rain samples collected in 2014 in Constitución confirm the tritium input estimate that we made using the New Zealand input data from similar latitude, and the IAEA data (http://www-naweb.iaea.org/napc/ih/IHS_resources_gnip.html). The mean residence time of the water in
On October 21, 2002, the Minister of Foreign Affairs of the Republic of Chile, Mrs. María Soledad Alvear, and the ESO Director General, Dr. Catherine Cesarsky, signed an Agreement that authorizes ESO to establish a new centre for astronomical observation in Chile.
Morales, S.; Soto-Sandoval, J.; Monardez, P.
The tsunami occurred on 27th February 2010 offshore central Chile due to a mega-thrust earthquake (Mw=8.8), showed a complex hydrodynamic behavior in the near field that is not completely understood and could not be well characterized using linear models (Cox 2011, Fujima 2011). Several floods separated by several minutes that lasted over eight hours, which flowed parallel to the coast were reported. A reasonable physical explication for this phenomena has been published. Due to the distance from the rupture zone to the coast is shorter than a complete tsunami wave, the latter cannot be created then secondary effects are triggered (Monárdez and Salinas, 2011). This was validated using numerical models based on RANS equations and measurements and field observations in the 2010 Chilean tsunami. Due to this knowledge, the 1868 and 1877 last mega-thrust earthquakes in the Southern Peru and Northern Chile are analyzed. This became necessary, since this zone is known as one the major seismic gap in the area. Scenarios with different fault parameters were implemented for the 1868 and 1877 tsunamis and important results were obtained. In both of the tsunamis, several floods were observed and the arrival time and direction of flow propagation were according to historical reports. In the 1868 tsunami, the effects on the Chilean coast are due to secondary effects such as it is described in historical observations, e.g. in Arica port three main floods 40, 120 and 156 minutes after the earthquakes are observed. In the 1877 tsunami secondary effects were present mainly on the Peruvian coast. Finally, a new classification for near and far field tsunami is proposed.
Baeza, Carlos; Finot, Víctor L; Ruiz, Eduardo
Alstroemeria L., one of the most diverse genera of the Chilean flora and of high floricultural value, is represented by 35 species, most of them distributed between 28-38° S in the Mediterranean zone of Central Chile. There are 24 complex-forming taxa, of which 18 have conservation problems (8 are considered "endangered" and 10 as "vulnerable"). One of these complexes is Alstroemeria presliana Herb. with two subspecies: subsp. presliana and subsp. australis Bayer. Alstroemeria presliana grows in Chile and Argentina: subsp. presliana is distributed from Reserva Nacional Siete Tazas (35°27' S, Region of Maule) to Antuco, (37°25' S, Region of Bío-Bío), and is also found in Neuquén, Argentina; subsp. australis is endemic to the Cordillera of Nahuelbuta. A comparative karyotype study was carried out among six populations of A. presliana subsp. presliana and five populations of A. presliana subsp. australis. The eleven populations presented an asymmetric karyotype, with 2n = 2× = 16 chromosomes but with different karyotype formulae. A. presliana subsp. presliana shows the haploid formula 2m + 2m-sat + 1sm-sat + 1st-sat + 1t + 1 t-sat, and A. preslianasubsp. australis presents a formula 1m + 2m-sat + 1sm + 2t + 2t-sat chromosomes. The architecture of the karyotype between the subspecies is very different. The scatter plot among CVCL vs. MCA shows different groupings between populations of the two subspecies. According to the results obtained it is possible to consider raising Alstroemeria presliana subsp. australis at species level.
Baeza, Carlos; Finot, Víctor L.; Ruiz, Eduardo
Alstroemeria L., one of the most diverse genera of the Chilean flora and of high floricultural value, is represented by 35 species, most of them distributed between 28–38° S in the Mediterranean zone of Central Chile. There are 24 complex-forming taxa, of which 18 have conservation problems (8 are considered “endangered” and 10 as “vulnerable”). One of these complexes is Alstroemeria presliana Herb. with two subspecies: subsp. presliana and subsp. australis Bayer. Alstroemeria presliana grows in Chile and Argentina: subsp. presliana is distributed from Reserva Nacional Siete Tazas (35°27′ S, Region of Maule) to Antuco, (37°25′ S, Region of Bío-Bío), and is also found in Neuquén, Argentina; subsp. australis is endemic to the Cordillera of Nahuelbuta. A comparative karyotype study was carried out among six populations of A. presliana subsp. presliana and five populations of A. presliana subsp. australis. The eleven populations presented an asymmetric karyotype, with 2n = 2× = 16 chromosomes but with different karyotype formulae. A. presliana subsp. presliana shows the haploid formula 2m + 2m-sat + 1sm-sat + 1st-sat + 1t + 1 t-sat, and A. preslianasubsp. australis presents a formula 1m + 2m-sat + 1sm + 2t + 2t-sat chromosomes. The architecture of the karyotype between the subspecies is very different. The scatter plot among CVCL vs. MCA shows different groupings between populations of the two subspecies. According to the results obtained it is possible to consider raising Alstroemeria presliana subsp. australis at species level. PMID:26273223
Friedlander, Alan M.; Ballesteros, Enric; Caselle, Jennifer E.; Gaymer, Carlos F.; Palma, Alvaro T.; Petit, Ignacio; Varas, Eduardo; Muñoz Wilson, Alex; Sala, Enric
The Juan Fernández and Desventuradas islands are among the few oceanic islands belonging to Chile. They possess a unique mix of tropical, subtropical, and temperate marine species, and although close to continental South America, elements of the biota have greater affinities with the central and south Pacific owing to the Humboldt Current, which creates a strong biogeographic barrier between these islands and the continent. The Juan Fernández Archipelago has ~700 people, with the major industry being the fishery for the endemic lobster, Jasus frontalis. The Desventuradas Islands are uninhabited except for a small Chilean military garrison on San Félix Island. We compared the marine biodiversity of these islands across multiple taxonomic groups. At San Ambrosio Island (SA), in Desventuradas, the laminarian kelp (Eisenia cokeri), which is limited to Desventuradas in Chile, accounted for >50% of the benthic cover at wave exposed areas, while more sheltered sites were dominated by sea urchin barrens. The benthos at Robinson Crusoe Island (RC), in the Juan Fernández Archipelago, comprised a diverse mix of macroalgae and invertebrates, a number of which are endemic to the region. The biomass of commercially targeted fishes was >2 times higher in remote sites around RC compared to sheltered locations closest to port, and overall biomass was 35% higher around SA compared to RC, likely reflecting fishing effects around RC. The number of endemic fish species was extremely high at both islands, with 87.5% of the species surveyed at RC and 72% at SA consisting of regional endemics. Remarkably, endemics accounted for 99% of the numerical abundance of fishes surveyed at RC and 96% at SA, which is the highest assemblage-level endemism known for any individual marine ecosystem on earth. Our results highlight the uniqueness and global significance of these biodiversity hotspots exposed to very different fishing pressures. PMID:26734732
Friedlander, Alan M; Ballesteros, Enric; Caselle, Jennifer E; Gaymer, Carlos F; Palma, Alvaro T; Petit, Ignacio; Varas, Eduardo; Muñoz Wilson, Alex; Sala, Enric
The Juan Fernández and Desventuradas islands are among the few oceanic islands belonging to Chile. They possess a unique mix of tropical, subtropical, and temperate marine species, and although close to continental South America, elements of the biota have greater affinities with the central and south Pacific owing to the Humboldt Current, which creates a strong biogeographic barrier between these islands and the continent. The Juan Fernández Archipelago has ~700 people, with the major industry being the fishery for the endemic lobster, Jasus frontalis. The Desventuradas Islands are uninhabited except for a small Chilean military garrison on San Félix Island. We compared the marine biodiversity of these islands across multiple taxonomic groups. At San Ambrosio Island (SA), in Desventuradas, the laminarian kelp (Eisenia cokeri), which is limited to Desventuradas in Chile, accounted for >50% of the benthic cover at wave exposed areas, while more sheltered sites were dominated by sea urchin barrens. The benthos at Robinson Crusoe Island (RC), in the Juan Fernández Archipelago, comprised a diverse mix of macroalgae and invertebrates, a number of which are endemic to the region. The biomass of commercially targeted fishes was >2 times higher in remote sites around RC compared to sheltered locations closest to port, and overall biomass was 35% higher around SA compared to RC, likely reflecting fishing effects around RC. The number of endemic fish species was extremely high at both islands, with 87.5% of the species surveyed at RC and 72% at SA consisting of regional endemics. Remarkably, endemics accounted for 99% of the numerical abundance of fishes surveyed at RC and 96% at SA, which is the highest assemblage-level endemism known for any individual marine ecosystem on earth. Our results highlight the uniqueness and global significance of these biodiversity hotspots exposed to very different fishing pressures.
The ESO Council, in its extraordinary session on 28 April 1994, among other matters discussed the relations with the Republic of Chile and the situation around Paranal mountain , the designated site for the ESO Very Large Telescope (VLT). Council decided to send a high ranking delegation to Santiago de Chile to discuss with Chilean authorities the pending problems, including the finalisation of the new Treaty between the Republic of Chile and ESO and the legal aspects of the Paranal location. The ESO delegation will consist of Dr. Peter Creola (President of ESO Council), Dr. Catherine Cesarsky (Vice-President of ESO Council), Dr. Henrik Grage (Former Vice-President of ESO Council) and Professor Riccardo Giacconi (ESO Director General), the latter accompanied by his advisers. The delegation will arrive in Chile during the second half of May 1994. The ESO delegation will meet with the Chilean Minister of Foreign Affairs, Mr. Carlos Figueroa, and the Secretary of State in the Ministry of Foreign Affairs, Mr. Jose Miguel Insulza. Other meetings at high level are being planned. The delegation will report about these discussions to the ESO Council during its ordinary session on 7 - 8 June 1994. FOUR PARANAL PHOTOS AVAILABLE A series of four photos which show the current status of the work at Paranal has been prepared. Photographic colour prints for use by the media can be requested from the ESO Information and Photographic Service (please remember to indicate the identification numbers).  See ESO Press Release 07/94 of 21 April 1994. PHOTO CAPTIONS ESO PR PHOTO 08/94-1: CERRO PARANAL This aerial photo of the Paranal mountain, the designated site for the ESO Very Large Telescope (VLT), was obtained on 22 March 1994. Paranal is situated in the driest part of the Chilean Atacama desert, approx. 130 km south of the city of Antofagasta, and about 12 km from the Pacific Ocean. In this view towards the West, the ocean is seen in the background. The altitude is 2650 metres
Dussaillant, Francisca; Guzmán, Eugenio
Chile has a long-standing history of natural disasters and, in particular, earthquakes. The latest big earthquake hit Chile on 27 February 2010 with a magnitude of 8.8 on the Richter scale. As an event that had a profound impact on significant portions of the population, the earthquake could theoretically have served to build trust by promoting new trust networks through the enhancement of distant family ties and the interaction between affected neighbours. This study offers an empirical analysis of this theory in the Chilean case. It finds that if initial social capital is very low (thus allowing for post-disaster looting and violence), then the impact of the trust-increasing effect is smaller. It also shows that the effect of the disaster was not transitory, but that it persisted and actually increased over time.
A study of television was conducted in Chile in 1971. There is a discontinuous aspect in the requests of the public, especially in times of crisis and rupture with the traditional order. In order to measure the various levels of appreciation and critique raised by the television in various areas of the working class in Chile, the poblaciones (peripheric residential zones) were chosen as the place for the study. 100 interviews were conducted. 60% of the people questioned were sympathizers or militants of the various left wing parties; the other 40% were sympathizers or militants of the opposition (Christian democracy, National party and right wing of the radical party). Television does not make any distinction between the publics, but the public makes distinctions between the effects of television. Melodramas and detective programs have the largest adhesion in the popular public of Latin America.
Rudnick, H. )
This article examines the deregulation of the electric power sector in Chile. Chile was the leader in Latin America in the restructuring of the electric power sector, and its case merits particular analysis. Although a small system (70% of installed capacity is hydroelectric with 2,800 MW maximum demand in 1993), its development has been observed with interest by many institutions, particularly by the World Bank and most recently by other Latin American countries, and several countries have followed its steps. The Chilean 1982 electricity law was a worldwide pioneer in deregulating the electric power sector to create market conditions where generators compete to provide electrical energy to large consumers, sharing a transmission system open to all and paying fees for that system. The law formalized what had taken place in the country since 1978, several years before market approaches were formulated in the US and implemented in the United Kingdom.
Yung, V; Favi, M; Fernandez, J
In Chile, dog rabies has been controlled and insectivorous bats have been identified as the main rabies reservoir. This study aimed to determine the rabies virus (RABV) variants circulating in the country between 2002 and 2008. A total of 612 RABV isolates were tested using a panel with eight monoclonal antibodies against the viral nucleoprotein (N-mAbs) for antigenic typing, and a product of 320-bp of the nucleoprotein gene was sequenced from 99 isolates. Typing of the isolates revealed six different antigenic variants but phylogenetic analysis identified four clusters associated with four different bat species. Tadarida brasiliensis bats were confirmed as the main reservoir. This methodology identified several independent rabies enzootics maintained by different species of insectivorous bats in Chile.
Root-Bernstein, M.; Montecinos Carvajal, Y.; Ladle, R.; Jepson, P.; Jaksic, F.
Private protected areas (PPAs) are important designations with the potential to complement and improve public protected area (PA) networks in many countries. PPAs come in many forms and offer a wide variety of incentives, rights, responsibilities, and protections. One popular model, now being considered for adoption in Chile, is the conservation easement. In this article, we examine how well conservation easements would perform as PPA designations in countries such as Chile that have strong mining industries. Mining, and other concessions, in PAs is emerging as an important point of contention between conservation and development. PPA designations should be carefully designed to offer protections that conform to standards that will complement PA networks, that are perpetual, and that require a publically accountable and transparent process to overturn or modify.
This paper seeks to highlight the problems of gaps in health infrastructure in Chile, and to analyze the mechanisms by which it is provided. In Chile this is done in two ways: the first is through competitive bidding or sector-wide modality. The second way is through hospital concessions. Both mechanisms have had difficulties in recent years, which are reported. Finally, we propose ways to improve the provision of health infrastructure in Chile.
Martinez, R.; Zolensky, M.; Martinez de Los Rios, E.
Desert regions can be productive meteorite recovery locations because of low humidity, minimal ground cover and, in favorable situations, high prevailing winds to deflate surfaces. For these reasons we have made reconnaissance searches of a particularly arid Atacama Desert tract between Antofagasta and Mejillones, Chile (approx. 23 degrees 15'S, 70 degrees 30'W). One of us (EMR) had previously collected new ordinary chondrites from this same area, which has been named Pampa (a), (b), (c), and (e). The Pampa de Agua Blanca (PAB) chondrite is also apparently from this same area. In our brief 1991 reconnaissance we found additional specimens of (a) and (c). All of these meteorites have been found as multiple stones, necessitating pairing studies. Consequently, we examined our finds (a, b, c, and e), borrowed specimens from the Field Museum (a, b, PAB) and Robert Haag (c), and have performed the first detailed studies of the Pampa meteorites. Here we summarize results of these studies. Shock levels refer to the classification developed by Stoffler et al. (1991). PAMPA (a): This weathered meteorite is represented by several partially fusion-crusted fragments with a combined mass of approximately 380 g. No distinct chondrules are evident in thin section, although some chondrule fragments are present; considerable recrystallization is evident and plagioclase (Ab(sub)80Or5-Ab(sub)83Or(sub)5) is present as clear grains. Diopside and hydroxylapatite are also present. Olivine (Fo(sub)75.0 mean, 0.4% mean deviation-PMD) exhibits no shock effects. We classify Pampa (a) as L6, shock level 1. PAMPA (b): This is a weathered meteorite represented by numerous individual stones with a combined weight of approximately 10 kg. We examined thin sections from four individual stones of (b). A few distinct barred chondrules are evident in thin section, along with numerous chondrule and aggregate fragments. Olivine (Fo(sub)74.8 mean, 0.9 PMD) exhibits undulatory extinction, planar fractures
Castilla, J C; Campo, M A; Bustamante, R H
We present the results for over two decades of monitoring on intertidal food-gatherers and the population of the low rocky shore dweller kelp Durvillaea antarctica, a short-distance disperser, inside and outside the no-take marine reserve, Estacion Costera de Investigaciones Marinas (ECIM), at Las Cruces, central Chile. It was hypothesized that protection of an initially extremely depleted population would recover by recolonizing first the no-take area and then adjacent non-protected (exploited) areas. We found that recovery of D. antarctica occurred slowly inside ECIM, with increase in density and biomass, of up to three orders of magnitude as compared to an adjacent non-protected area, which showed approximately 2-yr delay. These results suggest that the kelp population inside ECIM was likely regulated via intraspecific competition, which did not occur outside. Results showed no evidence for juvenile vs. adult density dependence other than a weak relationship for the central area of ECIM. These findings also suggest that the population recovery and cross-boundary seeding subsides affected the population dynamics. Understanding these dynamics may enhance management and conservation policies. Our work highlights the critical value of baseline and long-term comparative studies in marine no-take protected and non-protected areas for understanding how population processes respond to human and conservation practices.
relationship between criminal groups and drug dealers. Carabineros (Uniformed Police Force) and Investigaciones de Chile (Investigation Police) have...2004; available from <http://www.latercera.cl/ articulo /0,5819,3255_5664_49521165,00.html>; Internet; accessed 02 Feb 2004. 21 Military Studies and... articulo /0,5819,3255_5664_49521165,00.html> Internet. Accessed 02 February 2004. Williams, Phil. “New Contexts, Smart Enemies” in Non-State Threats and Future Wars, ed. Robert Bunker, Portland: Frank Cass & Co., 2003
Toro, J.; Vega, J. D.; Khan, A. S.; Mills, J. N.; Padula, P.; Terry, W.; Yadón, Z.; Valderrama, R.; Ellis, B. A.; Pavletic, C.; Cerda, R.; Zaki, S.; Shieh, W. J.; Meyer, R.; Tapia, M.; Mansilla, C.; Baro, M.; Vergara, J. A.; Concha, M.; Calderon, G.; Enria, D.; Peters, C. J.; Ksiazek, T. G.
An outbreak of 25 cases of Andes virus-associated hantavirus pulmonary syndrome (HPS) was recognized in southern Chile from July 1997 through January 1998. In addition to the HPS patients, three persons with mild hantaviral disease and one person with asymptomatic acute infection were identified. Epidemiologic studies suggested person-to-person transmission in two of three family clusters. Ecologic studies showed very high densities of several species of sigmodontine rodents in the area. PMID:9866751
Fernández, J; Vera, L; Tognarelli, J; Fasce, R; Araya, P; Villagra, E; Roos, O; Mora, J
We report the detection of dengue virus type 4 (DENV-4) for the first time in Easter Island, Chile. The virus was detected in serum samples of two patients treated at the Hospital in Easter Island. The two samples were IgM positive, and the infection was confirmed by RT-PCR and genetic sequencing; viral isolation was possible with one of them. The Easter Island isolates were most closely related to genotype II of dengue type 4.
immunologic familiarity with I this antigen, sera collected 10 days after immunization were examined by IgM "ELISA. In this instance significant rises of 0...do not have the same immunologic familiarity with S. typhi 0 antigen as Chilean children. U.S. adults respond to immun.zation as often with a primary...vaccination between May 3 and June 18, 1982. -25- REFERENCES 1. Departamento Planificacion Estadistica, Mjnisterio de Salud, Santiago Chile. 2. Ristori
The author examines the status of female migrant workers in Santiago, Chile, in the 1980s, with a focus on the level of poverty and social inequalities. Aspects considered include "the dramatic transformation in domestic service, the increase in the number of non-migrant, lower class women participating in the economy, and the limited and precarious status of women's employment in the more dynamic sectors of the economy." (SUMMARY IN ENG)
Casas, Lidia; Ahumada, Claudia
While Chile sees itself as a country that has fully restored human rights since its return to democratic rule in 1990, the rights of teenagers to comprehensive sexuality education are still not being met. This paper reviews the recent history of sexuality education in Chile and related legislation, policies and programmes. It also reports a 2008 review of the bylaws of 189 randomly selected Chilean schools, which found that although such bylaws are mandatory, the absence of bylaws to prevent discrimination on grounds of pregnancy, HIV and sexuality was common. In relation to how sexual behaviour and discipline were addressed, bylaws that were non-compliant with the law were very common. Opposition to sexuality education in schools in Chile is predicated on the denial of teenage sexuality, and many schools punish sexual behaviour where transgression is perceived to have taken place. While the wider Chilean society has been moving towards greater recognition of individual autonomy and sexual diversity, this cultural shift has yet to be reflected in the government's political agenda, in spite of good intentions. Given this state of affairs, the Chilean polity needs to recognise its youth as having human rights, or will continue to fail in its commitment to them.
Arriagada, G; Stryhn, H; Sanchez, J; Vanderstichel, R; Campistó, J L; Rees, E E; Ibarra, R; St-Hilaire, S
The sea louse is considered an important ectoparasite that affects farmed salmonids around the world. Sea lice control relies heavily on pharmacological treatments in several salmon-producing countries, including Chile. Among options for drug administration, immersion treatments represent the majority of antiparasitic control strategies used in Chile. As a topical procedure, immersion treatments do not induce a long lasting effect; therefore, re-infestation from neighbouring farms may undermine their efficacy. Synchronization of treatments has been proposed as a strategy to improve immersion treatment performance, but it has not been evaluated so far. Using a repeated-measures linear mixed-effect model, we evaluated the impact of treatment synchronization of neighbouring farms (within 10km seaway distance) on the adult lice mean abundance from weeks 2 to 8 post-treatment on rainbow trout and Atlantic salmon farms in Chile, while controlling for external and internal sources of lice before the treatments, and also for environmental and fish-related variables. Results indicate that treatment synchronization was significantly associated with lower adult lice levels from weeks 5 to 7 after treatment. This relationship appeared to be linear, suggesting that higher levels of synchronization may result in lower adult sea lice levels during these weeks. These findings suggest that synchronization can improve the performance of immersion delousing treatments by keeping sea lice levels low for a longer period of time. Our results may be applicable to other regions of the world where immersion treatments are widely used.
Léniz Martelli, Javiera; Van De Wyngard, Vanessa; Lagos, Marcela; Barriga, María Isabel; Puschel Illanes, Klaus; Ferreccio Readi, Catterina
Mortality rates for cervical cancer (CC) in Chile are higher than those of developed countries and it has an unequal socioeconomic distribution. The recognition of human papilloma virus (HPV) as the causal agent of cervical cancer in the early 80's changed the prevention paradigms. Current goals are to prevent HPV infection by vaccination before the onset of sexual activity and to detect HPV infection in women older than 30 years. This article reviews CC prevention and early detection methods, discusses relevant evidence to support a change in Chile and presents an innovation proposal. A strategy of primary screening based on HPV detection followed by triage of HPV-positive women by colposcopy in primary care or by cytological or molecular reflex testing is proposed. Due to the existence in Chile of a well-organized nationwide CC prevention program, the replacement of a low-sensitivity screening test such as the Papanicolau test with a highly sensitive one such as HPV detection, could quickly improve the effectiveness of the program. The program also has a network of personnel qualified to conduct naked-eye inspections of the cervix, who could easily be trained to perform triage colposcopy. The incorporation of new prevention strategies could reduce the deaths of Chilean women and correct inequities.
Smith, Malcolm G.; Sanhueza, P.; Schwarz, H. E.; Walker, A. R.
In 1999, after 6 years of intense work wirh Chilean authoritie Eduardo Frei Ruiz-Tagle, the then President of Chile signed into law Supreme Decree 686, the environmentally-linked "Norma Luminica". This, in effect, required that lighting in the three astronomically-sensitive Regions of Northern Chile (II Paranal,Armazones III Las Campanas IV La Silla, Tololo, Pachon) be directed downwards instead of into the sky. Various grace periods up to a maximum of five years were specified for different types of lighting. Street lighting was due to be fully compliant by 1st October, 2005. 70% of the street lighting in these 3 Regions now meets specifications and work continues towards full compliance. More sophisticated draft legislation is under consideration with several Chilean national authorities. This may include international lighting norms, energy-saving caps and measures to address energy-saving, environmental and human-health issues. With vigilance, these measures are likely to extend the useful life of all existing and major planned observatories in Chile by several decades.
Rodriguez, E. E.; Russo, R. M.; Mocanu, V. I.; Gallego, A.; Murdie, R.; Comte, D.
The Nazca-Antarctic plate boundary, the Chile spreading ridge, subducts beneath South America, forming the northward-migrating Chile Triple Junction (CTJ), now at ~46.5°S, where an actively spreading segment is currently in the Nazca trench. Ridge subduction is associated with diachronously developed variable structure and magmatism of overriding South America. To assess the effects of ridge subduction, we deployed a network of 39 broadband seismometers in southern Chile between 43 - 49°S and 71 - 76°W from Dec. 2004 - Feb. 2007, recording 102 earthquakes suitable for receiver function analyses, i.e., M > 5.9, of various backazimuths, and at epicentral distances of 30 - 90°. The network encompassed onland portions of the current triple junction and ridge subduction, areas to the south of the CTJ where ridge segments subducted during the last 6 m.y., and regions north of the CTJ not yet affected by ridge subduction, allowing the assessment of the effects of ridge subduction on crustal structure of overriding South America. We constructed 551 teleseismic receiver functions to estimate crustal thicknesses, H, and average compressional to shear wave velocity ratios, Vp/Vs = k, using the iterative time deconvolution method of Ligorria and Ammon (1999). H and k were calculated using the grid search method of Zhu and Kanamori (2000). Beneath stations closest to the trench, where the Nazca plate subducts, we found Moho depths between 28 and 55 km, thickening northward. At the locus of current ridge subduction, in the Taitao Pennisula, thinner crust ranges from 27 - 36 km. H is 36-38 km where the Antarctic plate subducts and the Chile ridge recently subducted. The direct effect of the subducting ridge on South America can be seen in H differences between forearc regions that have sustained ridge subduction versus those that have not. South American forearc crust above the subducted Nazca plate is as much as 28 km thicker than forearc crust recently affected by ridge
Colihueque, Nelson; Gantz, Alberto; Rau, Jaime Ricardo; Parraguez, Margarita
Abstract In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy. PMID:26668551
Colihueque, Nelson; Gantz, Alberto; Rau, Jaime Ricardo; Parraguez, Margarita
In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy.
Gana, Paulina; Tosdal, Richard M.
The U-Pb and K-Ar geochronology applied to intrusive rocks from the Coastal Batholith of Central Chile, demonstrates the existence of a basement block of the Mirasol Unit, with a crystallization age of 299??10 Ma, exposed in the northern block of the Melipilla Fault. The age of 214??1 Ma obtained in the 'Dioritas Gne??isicas de Cartagena Unit', indicates that a Late Triassic magmatism took place in this region; it coincides with the end of an extensive crustal melting period, proposed for northern Chile. The ages of the Jurassic plutonic units (Laguna Verde, Sauce, Pen??uelas and Limache) are restricted to the 156-161 Ma interval, showing in certain cases, inherited zircons from an unknown source. The difference between ages obtained using both chronological methods is a few million years, indicating that a short time passed between the crystallization and the cooling of the plutonic bodies, as well as a fast magmatic differentiation process. The Laguna Verde and Sauce Units, experienced a fast uplift, probably as a result of an extensional tectonic process in the magmatic arc, or induced by the magmatic pressure through fracture zones during Middle Jurassic.
Bürger, Raimund; Chowell, Gerardo; Mulet, Pep; Villada, Luis M
A spatial-temporal transmission model of 2009 A/H1N1 pandemic influenza across Chile, a country that spans a large latitudinal range, is developed to characterize the spatial variation in peak timing of that pandemic as a function of local transmission rates, spatial connectivity assumptions for Chilean regions, and the putative location of introduction of the novel virus into the country. Specifically, a metapopulation SEIR (susceptible-exposed-infected-removed) compartmental model that tracks the transmission dynamics of influenza in 15 Chilean regions is calibrated. The model incorporates population mobility among neighboring regions and indirect mobility to and from other regions via the metropolitan central region ('hub region'). The stability of the disease-free equilibrium of this model is analyzed and compared with the corresponding stability in each region, concluding that stability may occur even with some regions having basic reproduction numbers above 1. The transmission model is used along with epidemiological data to explore potential factors that could have driven the spatial-temporal progression of the pandemic. Simulations and sensitivity analyses indicate that this relatively simple model is sufficient to characterize the south-north gradient in peak timing observed during the pandemic, and suggest that south Chile observed the initial spread of the pandemic virus, which is in line with a retrospective epidemiological study. The 'hub region' in our model significantly enhanced population mixing in a short time scale.
Altieri, M.A.; Farrell, J.
Results are presented from a brief survey made in Nov-Dec 1982. Owners of small farms (up to 12 ha) generally have complex farming systems with a high diversity of enterprises, including the use of trees for a variety of purposes (food, fodder, wood, construction materials, fuel, etc.).
Delgado, F.; Pavez Alvarado, A.
La Pacana caldera is located in the Altiplano Puna Volcanic Complex in the Chilean Andes and is a 60 by 35 km NS elongated body. It is one of the largest resurgent calderas in the world, comparable to the supervolcanoes of La Garita, Toba and Yellowstone. It has been described as being formed 4 My ago during an eruption with a VEI of 8,7, which makes it the fifth largest eruption ever in the geological record. This eruption was followed by a subsidence of 0,9 up to 2 km according to previous studies. Different models for this caldera formation were proposed but with a lack of sub surface information. We hence carried a gravimetry study to investigate its inner structure and to better off constrains on these proposed models. The residual Bouguer anomaly (figure 1) is asymetric with multiple high and low gravity, with an average amplitude of -14 mGal, which reaches -24 mGal near the resurgent dome, interpreted as the deepest part of the caldera. Based on this, we propose that the main collapse zone is not related to the topographic border, but to resurgent dome edges. This is compatible with a piecemeal collapse geometry. There are several gravity highs below strato-volcanoes and postcaldera domes within La Pacana caldera, which are interpreted as magmatic reservoirs. Our data combined with previous geological studies allowed us to separate La Pacana in two nested calderas and to trace its NNW, N and NNE borders, previously unrecognized features. The 2,5 D forward modelling cross sections constrained with geological data showed that the maximum caldera depth is 1,3 km with a minimum of 0,6 km in its southern part. We finally suggest that caldera rims are surrounded by paleozoic basement uplifted by thrust fault systems. La Pacana's residual Bouguer anomaly is small (1/2) when compared with the ones associated to other supervolcanoes (Toba, Yellowstone). La Pacana caldera constitutes then an anomaly for supervolcanoes internal structure due to its interpreted low subsidence compared with several tens of km width. La Pacana caldera Bouguer residual anomaly (WGS84 UTM 19S). Thick blue lines indicate the caldera rim.
González, Alejandra V; Santelices, Bernabé
Chimerism occurs when two genetically distinct conspecific individuals fuse together generating a single entity. Coalescence and chimerism in red seaweeds has been positively related to an increase in body size, and the consequent reduction in susceptibility to mortality factors, thus increasing survival, reproductive potential and tolerance to stress in contrast to genetically homogeneous organisms. In addition, they showed that a particular pattern of post-fusion growth maintains higher genetic diversity and chimerism in the holdfast but homogenous axes. In Chilean kelps (brown seaweeds), intraorganismal genetic heterogeneity (IGH) and holdfast coalescence has been described in previous research, but the extent of chimerism in wild populations and the patterns of distribution of the genetically heterogeneous thallus zone have scarcely been studied. Since kelps are under continuous harvesting, with enormous social, ecological and economic importance, natural chimerism can be considered a priceless in-situ reservoir of natural genetic resources and variability. In this study, we therefore examined the frequency of IGH and chimerism in three harvested populations of Lessonia spicata. We then evaluated whether chimeric wild-type holdfasts show higher genetic diversity than erect axes (stipe and lamina) and explored the impact of this on the traditional estimation of genetic diversity at the population level. We found a high frequency of IGH (60-100%) and chimerism (33.3-86.7%), varying according to the studied population. We evidenced that chimerism occurs mostly in holdfasts, exhibiting heterogeneous tissues, whereas stipes and lamina were more homogeneous, generating a vertical gradient of allele and genotype abundance as well as divergence, constituting the first time "within- plant" genetic patterns have been reported in kelps. This is very different from the chimeric patterns described in land plants and animals. Finally, we evidenced that IGH affected genetic differentiation among populations, showed lower levels of FST index when we compared holdfast than lamina samples. In the light of this, future studies should evaluate the significance of chimeric holdfasts in their ability to increase kelps resilience, improve restoration and ecosystem service.
Chimerism occurs when two genetically distinct conspecific individuals fuse together generating a single entity. Coalescence and chimerism in red seaweeds has been positively related to an increase in body size, and the consequent reduction in susceptibility to mortality factors, thus increasing survival, reproductive potential and tolerance to stress in contrast to genetically homogeneous organisms. In addition, they showed that a particular pattern of post-fusion growth maintains higher genetic diversity and chimerism in the holdfast but homogenous axes. In Chilean kelps (brown seaweeds), intraorganismal genetic heterogeneity (IGH) and holdfast coalescence has been described in previous research, but the extent of chimerism in wild populations and the patterns of distribution of the genetically heterogeneous thallus zone have scarcely been studied. Since kelps are under continuous harvesting, with enormous social, ecological and economic importance, natural chimerism can be considered a priceless in-situ reservoir of natural genetic resources and variability. In this study, we therefore examined the frequency of IGH and chimerism in three harvested populations of Lessonia spicata. We then evaluated whether chimeric wild-type holdfasts show higher genetic diversity than erect axes (stipe and lamina) and explored the impact of this on the traditional estimation of genetic diversity at the population level. We found a high frequency of IGH (60–100%) and chimerism (33.3–86.7%), varying according to the studied population. We evidenced that chimerism occurs mostly in holdfasts, exhibiting heterogeneous tissues, whereas stipes and lamina were more homogeneous, generating a vertical gradient of allele and genotype abundance as well as divergence, constituting the first time “within- plant” genetic patterns have been reported in kelps. This is very different from the chimeric patterns described in land plants and animals. Finally, we evidenced that IGH affected genetic differentiation among populations, showed lower levels of FST index when we compared holdfast than lamina samples. In the light of this, future studies should evaluate the significance of chimeric holdfasts in their ability to increase kelps resilience, improve restoration and ecosystem service. PMID:28234957
Hildreth, W.; Singer, B.; Godoy, E.; Munizaga, F.
Cerro Campanario, a towering landmark on the continental divide near Paso Pehuenche, is a glacially eroded remnant of a mafic stratovolcano that is much younger than previously supposed. Consisting of fairly uniform basaltic andesite, rich in olivine and plagioclase, the 10-15 km3 edifice grew rapidly near the end of the middle Pleistocene, about 150-160 ka, as indicated by 40Ar/39Ar and unspiked K-Ar analyses of its lavas.
Pozo, Karla; Kukučka, Petr; Vaňková, Lenka; Přibylová, Petra; Klánová, Jana; Rudolph, Anny; Banguera, Yulieth; Monsalves, Javier; Contreras, Sergio; Barra, Ricardo; Ahumada, Ramón
PBDEs (10 congeners) were analyzed using GC-MS in superficial sediments and organisms of the Concepción Bay after the 2010 Tsunami. From all congeners analyzed PBDE-47, -99, -100 and -209 were the most frequently detected. Concentrations (ngg(-1) d.w.) in sediments for ΣPBDE-47, -99, -100 were low (0.02-0.09). However, PBDE-209 showed significantly higher values ∼20ngg(-1) d.w. This result were ∼10 times lower than those reported in a previous study of the 2010 Tsunami. The high result might be influenced by the massive urban debris dragged by the 2010 Tsunami. In organisms, concentrations of PBDE-47, -99, -100 (∼0.4ngg(-1) d.w.) were higher than those found in sediments (∼0.04ngg(-1) d.w.). Differences in PBDE pattern were also observed between different levels of the trophic food chain (primary and secondary consumers). This is the first attempt to assess the current status of Concepción Bay after the 2010 Tsunami.
Hildreth, W.; Moorbath, S.
Fifteen andesite-dacite stratovolcanoes on the volcanic front of a single segment of the Andean arc show along-arc changes in isotopic and elemental ratios that demonstrate large crustal contributions to magma genesis. All 15 centers lie 90 km above the Benioff zone and 280??20 km from the trench axis. Rate and geometry of subduction and composition and age of subducted sediments and seafloor are nearly constant along the segment. Nonetheless, from S to N along the volcanic front (at 57.5% SiO2) K2O rises from 1.1 to 2.4 wt %, Ba from 300 to 600 ppm, and Ce from 25 to 50 ppm, whereas FeO*/MgO declines from >2.5 to 1.4. Ce/Yb and Hf/Lu triple northward, in part reflecting suppression of HREE enrichment by deep-crustal garnet. Rb, Cs, Th, and U contents all rise markedly from S to N, but Rb/Cs values double northward - opposite to prediction were the regional alkali enrichment controlled by sediment subduction. K/Rb drops steeply and scatters greatly within many (biotite-free) andesitic suites. Wide diversity in Zr/Hf, Zr/Rb, Ba/Ta, and Ba/La within and among neighboring suites (which lack zircon and alkali feldspar) largely reflects local variability of intracrustal (not slab or mantle) contributions. Pb-isotope data define a limited range that straddles the Stacey-Kramers line, is bracketed by values of local basement rocks, in part plots above the field of Nazca plate sediment, and shows no indication of a steep (mantle+sedimentary) Pb mixing trend. 87Sr/86Sr values rise northward from 0.7036 to 0.7057, and 143Nd/144Nd values drop from 0.5129 to 0.5125. A northward climb in basal elevation of volcanic-front edifices from 1350 m to 4500 m elevation coincides with a Bougueranomaly gradient from -95 to -295 mgal, interpreted to indicate thickening of the crust from 30-35 km to 50-60 km. Complementary to the thickening crust, the mantle wedge beneath the front thins northward from about 60 km to 30-40 km (as slab depth is constant). The thick northern crust contains an abundance of Paleozoic and Triassic rocks, whereas the proportion of younger arc-intrusive basement increases southward. Primitive basalts are unknown anywhere along the arc. Base-level isotopic and chemical values for each volcano are established by blending of subcrustal and deep-crustal magmas in zones of melting, assimilation, storage and homogenization (MASH) at the mantle-crust transition. Scavenging of mid-to upper-crustal silicic-alkalic melts and intracrustal AFC (prominent at the largest center) can subsequently modify ascending magmas, but the base-level geochemical signature at each center reflects the depth of its MASH zone and the age, composition, and proportional contribution of the lowermost crust. ?? 1988 Springer-Verlag.
Hildreth, W.; Fierstein, J.; Godoy, E.; Drake, Robert E.; Singer, B.
A remote volcanic field in the rugged headwaters of the Rio Puelche and Rio Invernada (35.8??S) constitutes the largest cluster of Quaternary rhyolite lava flows yet identified in the Andean Southern Volcanic Zone. The Puelche Volcanic Field belongs to an intra-arc belt of silicic magmatic centers that extends, at least, 140 km north-south and lies well east of the volcanic front but nonetheless considerably west of the intraplate extensional fields of basaltic and alkaline centers of pampean Argentina. The authors' mapping has distinguished one shallow intrusive mass of early Pleistocene biotite rhyodacite (70.5% SiO2), 11 eruptive units of mid-Pleistocene high-K biotite-rhyolite lava (71.3-75.6% SiO2), and 4 eruptive units of basaltic andesite (53.95-4.9% SiO2), the conduits of which cut some of the rhyolites. Basal contacts of the rhyolite lava flows (and subjacent pyroclastic precursors) are generally scree covered, but glacial erosion has exposed internal flow structures and lithologic zonation superbly. Thicknesses of individual rhyolite lava flows range from 75 m to 400 m. Feeders for several units are well exposed. Cliff-draping unconformities and intracanyon relationships among the 11 rhyolite units show that the eruptive sequence spanned at least one glacial episode that accentuated the local relief. Lack of ice-contact features suggests, however, that all or most eruptions took place during non-glacial intervals probably between 400 ka and 100 ka. Post-eruptive glacial erosion reduced the rhyolites to several non-contiguous remnants that altogether cover 83 km2 and represent a surviving volume of about 21 km3. Consideration of slopes, lava thicknesses, and paleotopography suggest that the original area and volume were each about three times greater. Phenocryst content of the rhyolites ranges from 1 to 12%, with plagioclase>>biotite>FeTi oxides in all units and amphibole conspicuous in the least silicic. The chemically varied basaltic andesites range from phenocryst-poor to phenocryst-rich, exhibiting large differences in proportions of clinopyroxene, olivine, plagioclase, and xenocrystic quartz. Compositional bimodality of the volcanic field is striking, there being no Quaternary eruptive units having SiO2 contents between 55 and 70%. Major and trace element compositions of the mafic and silicic rocks are nonetheless typical of continental-margin arc suites, not of intracontinental suites. The lack of intermediate eruptive units and the differences between the mafic and rhyolitic lavas in Sr-isotope composition suggest that the rhyolites fractionated from a hybrid parent rather than continuously from basaltic magma. The rhyolites may contain larger contributions of upper-crustal partial melts than do silicic products of the volcanic-front centers 30 km to the west.
Molina, P. G.; Parada, M.; Gutierrez, F. J.; Chang-Qiang, M.; Jianwei, L.; Yuanyuan, L.
The Caleu pluton consists of three N-S elongated lithological zones: Gabbro-Diorite Zone (GDZ), Tonalite Zone (TZ) and Granodiorite Zone (GZ); western, middle and eastern portions of the pluton, respectively. The zones are thought to be previously differentiated in a common, isotopically depleted (Sr-Nd), subjacent magma reservoir at a 4 kbar equivalent depth. The emplacement should have occurred at the climax of the Cretaceous rifting. We present preliminary results of U238/Pb206 zircon geochronology; zircon saturation, Tsat(Zrn), and crystallization temperatures (Ti-in-Zrn); as well as relative oxidation states at time of crystallization, based on: (i) the sluggish REE and HFSE subsolidus diffusivities in zircon; (ii) the behavior of Ti4+↔Si4+ and Ce4+↔Zr4+ isovalent replacement, in addition to a constrained TiO2 activity in almost all typical crustal rocks; and (iii) relative oxidation states at time of crystallization, respectively. The latter are obtained by interpolation of the partition coefficients of trivalent (REE) and tetravalent (HFSE) curves in Onuma diagrams for each zircon, and then estimating relative Ce(IV)/Ce(III) ratios. Results obtained from 4 samples (a total of 77 zircon grains) collected from the three mentioned lithological zones indicate U/Pb ages of approximately 99.5 ±1.5 Ma, 96.8 ±0.6 Ma, and 94.4 +2.2 -0.8 Ma; and Ti-in Zrn ranges of ca. 720-870°C, ca. 680-820°C and ca. 750-840°C, for the GDZ, TZ and GZ samples, respectively. On the other hand Tsat(Zrn) of ca. 750-780°C in the TZ, and ca. 830-890°C in the GZ, were obtained. As expected saturation temperatures are similar or higher than Ti-in-Zrn obtained in zircon grains of TZ and GZ, respectively. Cathodoluminiscence images in zircon suggest a magmatic origin, due to absence of complex zoning patterns and fairly well conserved morphologies. Exceptionally the GDZ sample zircons show evidence of inheritance, indicating a xenocrystic and/or antecrystic origin. A relative Ce(IV)/Ce(III) decrease with temperature gives rise to separate trends for each zone, suggesting an independent unbuffered development at time of zircon formation. Taking into account variations in zircon ages, morphologies and crystallization ranges in the collected samples, it is suggested that zircon crystallization took place independent of the magma composition. Furthermore, old inherited zircon grains in the GDZ could be antecrysts, or products of a restricted and not major host rock assimilation, owing to the impossibility of basaltic magmas to saturate zircon crystals, and the isotopically depleted signature. This study is financed by CONICYT-FONDAP grant 15090013, Centro de Excelencia en Geotermia de los Andes (CEGA); and the CONICYT PBCT-PDA07, Programa Bicentenario de Ciencia y Tecnología.
Thamdrup, B; Canfield, D E
Rates and oxidative pathways of organic carbon mineralization were determined in sediments at six stations on the shelf and slope off Concepcion Bay at 36.5 degrees S. The depth distribution of C oxidation rates was determined to 10 cm from accumulation of dissolved inorganic C in 1-5-d incubations. Pathways of C oxidation were inferred from the depth distributions of the potential oxidants (O2, NO3-, and oxides of Mn and Fe) and from directly determined rates of SO4(2-) reduction. The study area is characterized by intense seasonal upwelling, and during sampling in late summer the bottom water over the shelf was rich in NO3- and depleted of O2. Sediments at the four shelf stations were covered by mats of filamentous bacteria of the genera Thioploca and Beggiatoa. Carbon oxidation rates at these sites were extremely high near the sediment surface (>3 micromol cm-3 d-1) and decreased exponentially with depth. The process was entirely coupled to SO4(2-) reduction. At the two slope stations where bottom-water O2 was > 100 microM, C oxidation rates were 10-fold lower and varied less with depth; C oxidation coupled to the reduction of O2, NO3-, and Mn oxides combined to yield an estimated 15% of the total C oxidation between 0 and 10 cm. Carbon oxidation through Fe reduction contributed a further 12-29% of the depth-integrated rate, while the remainder of C oxidation was through SO4(2-) reduction. The depth distribution of Fe reduction agreed well with the distribution of poorly crystalline Fe oxides, and as this pool decreased with depth, the importance of SO4(2-) reduction increased. The results point to a general importance of Fe reduction in C oxidation in continental margin sediments. At the shelf stations, Fe reduction was mainly coupled to oxidation of reduced S. These sediments were generally H2S-free despite high SO4(2-) reduction rates, and precipitation of Fe sulfides dominated H2S scavenging during the incubations. A large NO3- pool was associated with the Thioploca, and the shelf sediments were thus enriched in NO3- relative to the bottom water, with maximum concentrations of 3 micromol cm-3. The NO3- was consumed during our sediment incubations, but no effects on either C or S cycles could be discerned.
Morton, Robert A.; Gelfenbaum, Guy; Buckley, Mark L.; Richmond, Bruce M.
Geological effects of the 2010 Chilean tsunami were quantified at five near-field sites along a 200 km segment of coast located between the two zones of predominant fault slip. Field measurements, including topography, flow depths, flow directions, scour depths, and deposit thicknesses, provide insights into the processes and morphological changes associated with tsunami inundation and return flow. The superposition of downed trees recorded multiple strong onshore and alongshore flows that arrived at different times and from different directions. The most likely explanation for the diverse directions and timing of coastal inundation combines (1) variable fault rupture and asymmetrical slip displacement of the seafloor away from the epicenter with (2) resonant amplification of coastal edge waves. Other possible contributing factors include local interaction of incoming flow and return flow and delayed wave reflection by the southern coast of Peru. Coastal embayments amplified the maximum inundation distances at two sites (2.4 and 2.6 km, respectively). Tsunami vertical erosion included scour and planation of the land surface, inundation scour around the bases of trees, and channel incision from return flow. Sheets and wedges of sand and gravel were deposited at all of the sites. Locally derived boulders up to 1 m in diameter were transported as much as 400 m inland and deposited as fields of dispersed clasts. The presence of lobate bedforms at one site indicates that at least some of the late-stage sediment transport was as bed load and not as suspended load. Most of the tsunami deposits were less than 25 cm thick. Exceptions were thick deposits near open-ocean river mouths where sediment supply was abundant. Human alterations of the land surface at most of the sites provided opportunities to examine some tsunami effects that otherwise would not have been possible, including flow histories, boulder dispersion, and vegetation controls on deposit thickness.
Nelson, A.R.; Kashima, K.; Bradley, L.-A.
A reconnaissance of Holocene stratigraphy beneath fringing marshes of the Valdivia estuary, where an M 9.5 earthquake caused 1-2 m of regional coseismic subsidence in 1960, shows only fragmentary evidence of prehistoric coseismic subsidence. In most of the 150 hand-driven cores that were examined, a distinct unconformity separates 0.5-1.5 m of late Holocene tidal and floodplain mud, peat, and sand from underlying middle Holocene subtidal mud and sand. At the Las Coloradas site, where stratigraphy is best preserved, two A horizons of marsh and meadow soils abruptly overlain by sand and mud probably record coseismic subsidence shortly followed by tsunamis. The amount of subsidence during the earthquakes proved difficult to reconstruct with a diatom transfer function because of differences between modern and fossil diatom assemblages. Maximum 14C ages on macrofossils from the two A horizons at the Las Coloradas site of 1.7-1.3 ka and 2.7-1.7 ka allow correlation of the younger horizon with either of two of six 14C-dated A horizons buried by tsunami sand or post-tsunami tidal sand 200 km to the south at Maull??n, and with a lake-wide mass wasting event in Lago Puyehue, 100 km to the southeast. Tidal records of prehistoric coseismic subsidence at Valdivia are scarce because of a sea-level fall of 3-8 m over the past 6000 years, erosion of marsh and meadow soils during subsidence-induced flooding of the estuary, and largely complete land-level recovery during cycles of coseismic subsidence and postseismic uplift.
Morton, R.A.; Gelfenbaum, G.; Buckley, M.L.; Richmond, B.M.
Geological effects of the 2010 Chilean tsunami were quantified at five near-field sites along a 200. km segment of coast located between the two zones of predominant fault slip. Field measurements, including topography, flow depths, flow directions, scour depths, and deposit thicknesses, provide insights into the processes and morphological changes associated with tsunami inundation and return flow. The superposition of downed trees recorded multiple strong onshore and alongshore flows that arrived at different times and from different directions. The most likely explanation for the diverse directions and timing of coastal inundation combines (1) variable fault rupture and asymmetrical slip displacement of the seafloor away from the epicenter with (2) resonant amplification of coastal edge waves. Other possible contributing factors include local interaction of incoming flow and return flow and delayed wave reflection by the southern coast of Peru. Coastal embayments amplified the maximum inundation distances at two sites (2.4 and 2.6. km, respectively). Tsunami vertical erosion included scour and planation of the land surface, inundation scour around the bases of trees, and channel incision from return flow. Sheets and wedges of sand and gravel were deposited at all of the sites. Locally derived boulders up to 1. m in diameter were transported as much as 400. m inland and deposited as fields of dispersed clasts. The presence of lobate bedforms at one site indicates that at least some of the late-stage sediment transport was as bed load and not as suspended load. Most of the tsunami deposits were less than 25. cm thick. Exceptions were thick deposits near open-ocean river mouths where sediment supply was abundant. Human alterations of the land surface at most of the sites provided opportunities to examine some tsunami effects that otherwise would not have been possible, including flow histories, boulder dispersion, and vegetation controls on deposit thickness. ?? 2011.
CLIGEN (CLImate GENerator) is a stochastic weather generator that produces daily estimates of precipitation and individual storm parameters, including time to peak, peak intensity and storm duration. These parameters are typically used as inputs for other models, such as the Water Erosion Prediction...
Tang, Liujuan; Titov, Vasily V.; Moore, Christopher; Wei, Yong
The magnitude 8.3 earthquake in central Chile on 16 September 2015 and the resulting tsunami severely affected the region, with 15 deaths ( Onemi in Monitoreo por sismo de mayor intensidad. (In Spanish) [Available at: http://www.onemi.cl/alerta/se-declara-alerta-roja-por-sismo-de-mayor-intensidad-y-alarma-de-tsunami/], 2015), over one million evacuated, and flooding in nearby coastal cities. We present our real-time assessment of the 2015 Chile tsunami using the Short-term Inundation Forecasting for Tsunamis system, and post-event analyses with local community models in Chile. We evaluate three real-time tsunami sources, which were inverted at the time that the first quarter-, half-, and full-wave passed the first tsunameter (DART 32402, located approximately 580 km north-northwest of the epicenter), respectively. Measurement comparisons from 26 deep-ocean tsunameters and 38 coastal tide stations show that good model accuracies are achieved for all three sources, particularly for the local sites that recorded the most destructive waves. The study highlights the forecast speed, time and accuracy dependence, and their implications for the local forecast capability. Our analyses suggest that the tsunami's main origination area is about 100-200 km long and 100 km wide, to the north of the earthquake epicenter along the trench and the total estimated tsunami wave energy is 7.9 × 1013 J (with 13 % uncertainty). The study provides important guidelines for the earliest reliable estimate of tsunami energy and local forecasts. They can be obtained with the first quarter-wave of tsunameter recording. These results are also confirmed by a forecast analysis of the 2011 Japan tsunami. Furthermore, we find that the first half-wave tsunameter data are sufficient to accurately forecast the 2015 Chile tsunami, due to the specific orientation between the nearest tsunameter and the source. The study also suggests expanding the operational use of the local community models in real
... continental United States of fresh Cape gooseberry fruit (Physalis peruviana L.) with husks from Chile. Based... fresh Cape gooseberry fruit (Physalis peruviana L.) with husks from Chile. We solicited comments on...
Bedregal, Paula; Hernández, Viviana; Mingo, M Verónica; Castañón, Carla; Valenzuela, Patricia; Moore, Rosario; de la Cruz, Rolando; Castro, Daniela
Early child development is a population determinant of physical, mental and social health. To know the base line situation prior to the implementation of "Chile grows with you" (Chile Crece Contigo) is key to its evaluation.
Cigolini, C.; Laiolo, M.; Coppola, D.; Ulivieri, G.
We report data from a radon survey conducted at Villarrica volcano. Measurements have been obtained at selected sites by E-PERM® electrets and two automatic stations utilizing DOSEman detectors (SARAD Gmbh). Mean values for Villarrica are 1600 (±1150) Bq/m3 are similar to values recorded at Cerro Negro and Arenal in Central America. Moderately higher emissions, at measurement sites, were recorded on the NNW sector of the volcano and the summit, ranging from 1800 to 2400 Bq/m3. These measurements indicate that this area could potentially be a zone of flank weakness. In addition, the highest radon activities, up to 4600 Bq/m3, were measured at a station located near the intersection of the Liquiñe-Ofqui Fault Zone with the Gastre Fault Zone. To date, the Villarrica radon measurements reported here are, together with those collected at Galeras (Colombia), the sole radon data reported from South American volcanoes. This research may contribute to improving future geochemical monitoring and volcano surveillance.
Clouds and haze cover most of the Italian peninsula in this view of central Italy (41.5N, 14.0E) but the Bay of Naples region with Mt. Vesuvius and the island of Capri are clear. The Adriatic Sea in the background separates Italy from the cloud covered Balkans of eastern Europe and the Tyrrhenian Sea in the foreground lies between the Italian mainland and the off scene islands of Corsica and Sardinia. Several aircraft contrails can also be seen.
Introduction and Purpose of the Study Immigrants in Chile have diverse characteristics and include socioeconomically deprived populations. The location of socioeconomically deprived immigrants is important for the development of public policy intelligence at the local and national levels but their areas of residence have not been mapped in Chile. This study explored the spatial distribution of socioeconomic deprivation among immigrants in Chile, 1992–2012, and compared it to the total population. Material and Methods Areas with socioeconomically deprived populations were identified with a deprivation index which we developed modelled upon the Index of Multiple Deprivation (IMD) for England. Our IMD was based upon the indicators of unemployment, low educational level (primary) and disability from Census data at county level for the three decades 1992, 2002 and 2012, for 332, 339 and 343 counties respectively. We developed two versions of the IMD one based on disadvantage among the total population and another focused upon the circumstances of immigrants only. We generated a spatial representation of the IMD using GIS, for the overall IMD score and for each dimension of the index, separately. We also compared the immigrants´ IMD to the total population´s IMD using Pearson´s correlation test. Results Results showed that socioeconomically deprived immigrants tended to be concentrated in counties in the northern and central area of Chile, in particular within the Metropolitan Region of Santiago. These were the same counties where there was the greatest concentration of socioeconomic deprivation for the total population during the same time periods. Since 1992 there have been significant change in the location of the socioeconomically deprived populations within the Metropolitan Region of Santiago with the highest IMD scores for both the total population and immigrants becoming increasingly concentrated in the central and eastern counties of the Region. Conclusion
... Notification of the Next Meetings of the U.S.-Chile FTA Environmental Affairs Council and ECA Joint Commission... State. ACTION: Notice of the next meeting of the U.S.-Chile Free Trade Agreement Environmental Affairs... States Trade Representative (``USTR'') are providing notice that the United States and Chile intend...
... (Second Review)] Preserved Mushrooms From Chile, China, India, and Indonesia; Determinations On the basis...)), that revocation of the antidumping duty orders on preserved mushrooms from Chile, China, India, and... determines that revocation of the antidumping duty order on preserved mushrooms from Indonesia would not...
The work of Dr. Claudio Costa Casaretto covers a broad field in the history of Medicine in Chile. He contributed with the historical aspects in the Centennial issue of Revista Médica de Chile in July, 1972. He published 85 papers in this journal in a lapse of 20 years. In his works, he investigated about medical personalities with the highest relevance for Chilean medicine such as Dr. William Blest, graduated in Edinburgh and director of the first Medicine Course in Chile in 1833, the French obstetrician Dr. Lorenzo Sazie, first Dean of the Faculty of Medicine of the University of Chile in 1843 and Dr. Eloisa Díaz, first physician graduated in Chile and South America in 1887. He published the translation from Latin of Juan Ignacio Molina's verses "Elegies to smallpox", Chilean writer and erudite of the XVIII century. He also undertook the origins of Universidad de San Felipe (1737), Universidad de Chile (1842) and Pontificia Universidad Católica de Chile (1889) and the main educational events occurred in the Faculty of Medicine of the University of Chile, during the past century. He also published about the public health situation and sanitary care during the XIX century, about the conflict between private and public teaching and other political events of the past century. The work of Dr. Costa as a whole, is a real history textbook of Chilean Medicine. Dr. Costa and Dr. Enrique Laval are the most important Chilean medical historians of the XX century.
... pomegranates from Chile using mitigation measures other than fumigation with methyl bromide. DATES: We will... with methyl bromide. The Animal and Plant Health Inspection Service (APHIS) also received a request... fresh figs and pomegranates from Chile using mitigation measures other than fumigation with...
... baby kiwi from Chile using mitigation measures other than fumigation with methyl bromide. DATES... (Actinidia arguta) from Chile was allowed only if the fruit was fumigated with methyl bromide. On March 21... United States under a systems approach. The systems approach provides an alternative to fumigation...
Blueberry (Vaccinium spp.) has great economic importance in Chile, currently with about 8,500 ha being cultivated. Recently, the presence of canker and dieback symptoms has been observed along the productive blueberry zone of Chile extending from the V Region (32º49´ South lat.) in the north to the ...
Corvalan-Vasquez, Oscar E.
The development of apprenticeship programs in several Latin American countries was investigated with a focus on the results of an industrial apprenticeship program in Santiago, Chile. The program studied was the Instituto Nacional de Capacitacion Profesional (INACAP), the national vocational training institute of Chile. The purpose of the study…
Arias-Bohart, Elizabeth T.
Abstract Carlota gen. n., with one included species C. coigue sp. n., is described and illustrated from the Valdivian forests of Chile. The relationships of this genus to other Agrypnini from Chile are discussed and generic key for Chilean Agrypninae genera is provided. PMID:25061355
Narodowski, Mariano; Nores, Milagros
The view that competition initiatives in education, such as Chile's introduction of vouchers, promote socioeconomic segregation in schools is questioned. Chile and Argentina have faced very different decentralization reforms, carried out within different regulatory frameworks, but have arrived at similar situations in terms of schools'…
Crosta, G.; Hermanns, R. L.; Valbuzzi, E.; Dehls, J.; Yugsi Molina, F. X.; Sepulveda, S.
The western slope of the Andes of northern Chile - southern Perù is generally subdivided from the west to the east into the morphological units of: the Coastal Cordillera, Central Depression, the Western Escarpment-Precordillera and the Western Andean Cordillera. The western escarpment and Precordillera are formed by the Azapa coarse-grained clastic formation (sandstones, conglomerates, mudstones) and the Oxaya (rhyodacitic ignimbrites) and Diablo volcanoclastic formations (Oligocene and Miocene). Important uplift has been suggested between the deposition of the Oxaya and Diablo formations. The entire area has been characterized by a long-term hyperaridity (Atacama desert), initially established between 20 and 15 Ma, and this caused a strong difference between the long term continuous uplift and low denudation rates. This long sector of the central western escarpment and Precordillera is incised by deep canyons and subparallel drainage network in the upper part. The drainage network developed in two main phases: a lower-middle Miocene phase with formation of a parallel poorly structured drainage network cutting into the Oxaya formation, and presently well preserved; the canyons have been incised in the initial topography starting around 9 Ma and up to about 3.8 Ma with subsequent refilling episodes. Valley incision (ave. rate of 0.2 mm yr-1) has been controlled by topographic uplift and less arid climate (after 7 Ma). As a consequence of these geologic and climatic settings the evolution of this area has been characterized by canyon incision and extremely large slope instabilities. These slope instabilities occur in the "interfluvial" sectors of the western escarpment and Precordillera and along the canyon flanks. Landslides affecting the preserved paleosurfaces, interested by the parallel drainage network in the Oxaya formation, involve volumes of various cubic kilometres (Lluta collapse, Latagualla Landslide) and can control the drainage network. These mega
With this issue, Revista Médica de Chile will have been published uninterruptedly, for 130 years. Formal medical education had an early development since Chile became independent from Spain (1817). The first Medical Sciences Course was organized in 1833 by the Irish physician William C Blest. The Santiago Medical Society was founded in 1869 and its journal-Revista Médica de Chile--in 1872. Its first director was Dr. German Schneider. Revista Medica is the oldest serial publication in South America and the second oldest in the Spanish speaking world. This is a remarkable fact for a comparatively young country. With the creation of the Medical Society and Revista Medica, a process of continuous medical education was started and they became a real Graduate School. The Journal has adopted the main changes in knowledge and technology. Some important milestones of its development, during the second half of the 20th century, were the definition of its objectives and structure, the incorporation of peer review of manuscripts (even with foreign reviewers) the adoption of international guidelines for publication, its incorporation into the main biomedical journal indexes, the modernization of its printing process, the making of a computer generated index of all papers published since 1872, its incorporation into a digital library in INTERNET and the active participation of its editors in the World Association of Medical Journal Editors. The success of the journal is influenced by the independence that the Medical Society has conferred to the editors (all outstanding University Professors), as well as to the characteristics of an educational campus "invisible and without tumult" (Ingelfinger).
Chile's 1st case of AIDS was diagnosed in 1984. Some 250 AIDS cases and 1600 HIV positive persons have since been reported, although the actual number by some estimates may reach 5000. Chile, although in the initial stages of the epidemic, already has a serious problem which at present can only be combatted through education. It will be necessary to convince the population that significant modifications of sexual behavior are needed to control the spread of the disease. Education for AIDS prevention is a priority of the National Commission on AIDS (CONASIDA), which is basing its program on the premise that stable monogamy is the most natural form of expression of a couple. Manuals for prevention are under development, and the 1st, for health workers and the general population, is in process of publication. A series of pamphlets and educational videos for workers in sexually transmitted disease clinics are under development. Educational materials are also being created for specific groups such as university students and agricultural workers and for groups at high risk. A social communications campaign has been prepared and approved by the authorities, and is awaiting funding for dissemination. Education of the population is also a concern for the Catholic Church, which views reinforcement of the family and its mission of providing sex education as a primary means of preventing AIDS. CONASIDA is also responsible for epidemiological study of AIDS in Chile through surveillance of sentinel groups and in quality control of the blood supply. Condoms are to be distributed in sexually transmitted disease clinics for the purpose of AIDS prevention.
Pellegrini Filho, Alberto; Zurita, Laura
This piece provides an initial assessment of the First Citizen Consensus Conference, an event held in the city of Santiago, Chile, from 22-24 November 2003, on the subject of "The Management of My Medical Record." This conference was the first citizen consensus conference that has been held in Chile as well as the first such conference in Latin America. Consensus conferences were devised by the Danish Board of Technology in 1987 as a way to assess science and technology issues through discussions between experts and a panel of lay persons. At the end of a consensus conference, the lay persons express their opinions and recommendations in a consensus report that is directed at policymakers, decision-makers, and the public in general. The objective of a consensus conference is to bridge the gaps that routinely exist among the general public, experts, and elected officials. So far, the Danish Board of Technology has organized more than 20 of these conferences, using a methodology that has become established as a model. Taking into account the changes that have occurred in the relationship between science and society at large, the Pan American Health Organization has decided to support the holding of consensus conferences in Latin America and the Caribbean. The First Citizen Consensus Conference adapted the Danish methodology to conditions in Chile, and this piece assesses the modifications that were made. In addition, some 6 to 12 months after the conference, there will be an external evaluation of the outcomes and impact of the conference, especially in the communications media, public debate, decision-making, and perceptions of the persons who were involved. Despite the criticisms made in this piece and some shortcomings that are pointed out, the First Citizen Consensus Conference achieved all of its objectives and will serve as an excellent model for similar conferences in other countries of the Americas.
Questions from patients about pain conditions and analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. The topic addressed in this issue is central pain, a neuropathic pain syndrome caused by a lesion in the brain or spinal cord that sensitizes one's perception of pain. It is a debilitating condition caused by various diseases such as multiple sclerosis, strokes, spinal cord injuries, or brain tumors. Varied symptoms and the use of pharmacological medicines and nonpharmacological therapies will be addressed.
Mortality by abortion has continuously decreased over the past fifty years in Chile. In fact, maternal death as a result of an induced abortion has become an exceptionally rare phenomenon in epidemiological terms (a risk of 1 in 4 million pregnant women of fertile age or 0.4 per 100,000 life births for abortion of any type, excluding ectopic pregnancy). After abortion became illegal in 1989, deaths related to abortion continued to decrease from 10.8 to 0.39 per 100,000 live births. This scientific fact challenges the common notion that less permissive abortion laws lead to greater mortality associated with abortion.
Heusser, C J
Pollen of southern beech and podocarp at Laguna de Tagua Tagua during the late Pleistocene indicates that cooler and more humid intervals were a feature of Ice Age climate at this subtropical latitude in Chile. The influence of the southern westerlies may have been greater at this time, and the effect of the Pacific anticyclone was apparently weakened. The climate today, wet in winter and dry in summer, supports broad sclerophyll vegetation that developed during the Holocene with the arrival of paleo-Indians and the extinction of mastodon and horse.
Abstract Chile, a middle-income country, recently joined Israel and Singapore as the world’s only countries to require reciprocity as a precondition for organ transplantation. The Chilean reform includes opt-out provisions designed to foster donation and priority for organ transplantation for registered people. Although the reform has had serious difficulties in achieving its mission, it can be reviewed by other countries that seek to address the serious shortage of organs. As increased organ donation can substantially enhance or save more lives, the effect on organ availability due to incentives arising from rules of preference should not be underestimated. PMID:25767299
Aguilera, Pablo; Garrido, Marcela; Lessard, Eli; Swanson, Julian; Mallon, William K.; Saldias, Fernando; Basaure, Carlos; Lara, Barbara; Swadron, Stuart P.
Introduction While a nationwide poison control registry exists in Chile, reporting to the center is sporadic and happens at the discretion of the treating physician or by patients’ self-report. Moreover, individual hospitals do not monitor accidental or intentional poisoning in a systematic manner. The goal of this study was to identify all cases of intentional medication overdose (MO) that occurred over two years at a large public hospital in Santiago, Chile, and examine its epidemiologic profile. Methods This study is a retrospective, explicit chart review conducted at Hospital Sótero del Rio from July 2008 until June 2010. We included all cases of identified intentional MO. Alcohol and recreational drugs were included only when they were ingested with other medications. Results We identified 1,557 cases of intentional MO and analyzed a total of 1,197 cases, corresponding to 0.51% of all emergency department (ED) presentations between July 2008 and June 2010. The median patient age was 25 years. The majority was female (67.6%). Two peaks were identified, corresponding to the spring of each year sampled. The rate of hospital admission was 22.2%. Benzodiazepines, selective serotonin reuptake inhibitors, and tricyclic antidepressants (TCA) were the causative agents most commonly found, comprising 1,044 (87.2%) of all analyzed cases. Acetaminophen was involved in 81 (6.8%) cases. More than one active substance was involved in 35% of cases. In 7.3% there was ethanol co-ingestion and in 1.0% co-ingestion of some other recreational drug (primarily cocaine). Of 1,557 cases, six (0.39%) patients died. TCA were involved in two of these deaths. Conclusion Similar to other developed and developing nations, intentional MO accounts for a significant number of ED presentations in Chile. Chile is unique in the region, however, in that its spectrum of intentional overdoses includes an excess burden of tricyclic antidepressant and benzodiazepine overdoses, a relatively low rate
Chile, a middle-income country, recently joined Israel and Singapore as the world's only countries to require reciprocity as a precondition for organ transplantation. The Chilean reform includes opt-out provisions designed to foster donation and priority for organ transplantation for registered people. Although the reform has had serious difficulties in achieving its mission, it can be reviewed by other countries that seek to address the serious shortage of organs. As increased organ donation can substantially enhance or save more lives, the effect on organ availability due to incentives arising from rules of preference should not be underestimated.
Haye, Pilar A.; Segovia, Nicolás I.; Muñoz-Herrera, Natalia C.; Gálvez, Francisca E.; Martínez, Andrea; Meynard, Andrés; Pardo-Gandarillas, María C.; Poulin, Elie; Faugeron, Sylvain
The role of dispersal potential on phylogeographic structure, evidenced by the degree of genetic structure and the presence of coincident genetic and biogeographic breaks, was evaluated in a macrogeographic comparative approach along the north-central coast of Chile, across the biogeographic transition zone at 30°S. Using 2,217 partial sequences of the mitochondrial Cytochrome Oxidase I gene of eight benthic invertebrate species along ca. 2,600 km of coast, we contrasted dispersal potential with genetic structure and determined the concordance between genetic divergence between biogeographic regions and the biogeographic transition zone at 30°S. Genetic diversity and differentiation highly differed between species with high and low dispersal potential. Dispersal potential, sometimes together with biogeographic region, was the factor that best explained the genetic structure of the eight species. The three low dispersal species, and one species assigned to the high dispersal category, had a phylogeographic discontinuity coincident with the biogeographic transition zone at 30°S. Furthermore, coalescent analyses based on the isolation-with-migration model validate that the split between biogeographic regions north and south of 30°S has a historic origin. The signatures of the historic break in high dispersers is parsimoniously explained by the homogenizing effects of gene flow that have erased the genetic signatures, if ever existed, in high dispersers. Of the four species with structure across the break, only two had significant albeit very low levels of asymmetric migration across the transition zone. Historic processes have led to the current biogeographic and phylogeographic structure of marine species with limited dispersal along the north-central coast of Chile, with a strong lasting impact in their genetic structure. PMID:24586356
Silva, Claudio; Andrade, Isabel; Yáñez, Eleuterio; Hormazabal, Samuel; Barbieri, María Ángela; Aranis, Antonio; Böhm, Gabriela
The effects of climate change on ocean conditions will have impacts on fish stocks, primarily through physiological and behavioural effects, such as changes in growth, reproduction, mortality and distribution. Habitat and distribution predictions for marine fishery species under climate change scenarios are important for understanding the overall impacts of such global changes on the human society and on the ecosystem. In this study, we examine the impacts of climate change on anchovy fisheries off Chile using predicted changes in global models according to the National Centre for Atmospheric Research (NCAR) Community Climate System Model 3.0 (CCSM3) and IPCC high future CO2 emission scenario A2, habitat suitability index (HSI) models and satellite-based sea surface temperature (SST) and chlorophyll-a (Chl-a) estimates from high-resolution regional models for the simulation period 2015-2065. Predictions of SST from global climate models were regionalised using the Delta statistical downscaling technique. Predictions of chlorophyll-a were developed using historical Chl-a and SST (2003-2013) satellite data and applying a harmonic model. The results show an increase in SST of up to 2.5 °C by 2055 in the north and central-south area for an A2 scenario. The habitat suitability index model was developed using historical (2001-2011) monthly fisheries and environmental data. The catch per unit effort (CPUE) was used as an abundance index in developing the HSI models and was calculated as the total catch (ton) by hold capacity (m3) in a 10‧ × 10‧ fishing grid square of anchovy, integrated over one month of fishing activity. The environmental data included the distance to coast (DC), thermal (SST) and food availability (Chl-a) conditions. The HSI modelling consists of estimating SI curves based on available evidence regarding the optimum range of environmental conditions for anchovy and estimating an integrated HSI using the Arithmetic Mean Model (AMM) method. The
Francis, Peter W.
A series of false color composite images covering the volcanic cordillera was written. Each image is 45 km (1536 x 1536 pixels) and was constructed using bands 7, 4, and 2 of the Thematic Mapper (TM) data. Approximately 100 images were prepared to date. A set of LANDSAT Multispectral Scanner (MSS) images was used in conjunction with the TM hardcopy to compile a computer data base of all volcanic structure in the Central Andean province. Over 500 individual structures were identified. About 75 major volcanoes were identified as active, or potentially active. A pilot study was begun combining Shuttle Imaging Radar (SIR) data with TM for a test area in north Chile and Bolivia.
Paulmier, A.; Ruiz-Pino, D.; Garçon, V.; Farías, L.
Processes regulating OMZs persistence in the oxygenated ocean remain poorly understood. Four cruises (21°-30°S) and fixed-point monitoring (36°S) between 2000 and 2002 using techniques adapted to O2 conditions as low as 1 μM allow a preliminary analysis of the entire Chilean OMZ structure. A shallow OMZ is observed in the three studied areas, although its structure differs. Off northern and central Chile, the OMZ is a permanent feature, more pronounced at the coast than further offshore. On the shelf, it forms in spring and erodes in fall. A conceptual model of two intermittent active or passive phases (intense or low biogeochemical O2 consumption) is proposed as a key mechanism for the local OMZ maintaining. The highest O2 consumptions are paradoxically favoured at the oxycline when the OMZ is less intense as offshore and on the shelf in spring and fall, suggesting a control by O2 availability of the OMZ remineralization.
Oliveira, R E; Neves, W A
After almost 2000 years of local development, including limited trading with neighboring ethnic groups, the societies that occupied the oases of San Pedro de Atacama, Northern Chile, became part of the trade web of the Tiwanaku empire, between 500 and 1000 CE. Archaeological evidence tends to support the idea that the period under the influence of the altiplano (high plane) empire was very affluent. Here we investigate the possibility that this affluence had a positive impact on the health status of the Atacameneans, using the oral health as an indirect indicator of quality of life. Dental decay, dental abscess, dental wear, linear enamel hypoplasia, periodontal disease and dental calculus were analyzed on 371 skeletons from 12 sites from San Pedro de Atacama oases. We believe that if, indeed, there were better biological conditions during the altiplano influence, this could have been caused by the access to a more diversified food intake promoted by the intensification of the trading network established by Tiwanaku in the central-south Andes, of which San Pedro de Atacama became an important node.
Waylen, Peter R.; Caviedes, César N.
The El Niño-Southern Oscillation (ENSO) phenomenon has been shown to influence dramatically precipitation and streamflow in tropical western South America. The statistical properties of annual and winter precipitation totals and streamflow characteristics in the Aconcagua River basin, in temperate central Chile, are investigated in such a way as to permit the identification of flood- and drought-generating processes and their possible linkages to upset behavior in the tropical Pacific. Despite the considerable distance to those regions generally associated with ENSO events, the phenomenon produces marked effects upon the various physical processes which govern the surface hydrometeorology of the study area. El Niño years result in significant increases in annual and winter precipitation, particularly along the coastal margin. The likelihood of rain or rain-on-snow flooding, in the succeeding winter, increases, as does the size of spring snowmelt in the southern summer, 1 year after the upset conditions in the tropical region. Annual low flows are of higher magnitude and occur earlier in the year than is usual.
Muñoz-Leal, Sebastián; Venzal, José M; González-Acuña, Daniel; Nava, Santiago; Lopes, Marcos G; Martins, Thiago F; Figueroa, Cecilia; Fernández, Nicolás; Labruna, Marcelo B
Ornithodoros atacamensis n. sp. is described from larvae collected on the lizard Liolaemus bisignatus and from free-living adults collected in desert areas from the Pan de Azúcar and Llanos de Challe National Parks, in Northern Chile. Additionally, unengorged larvae were obtained from fertilized females, which laid eggs in the laboratory. Morphological and mitochondrial 16S rDNA sequence analyses were performed in order to compare this new soft tick species with other congeneric Neotropical representatives. Larvae of O. atacamensis are morphologically closely related to Ornithodoros talaje sensu stricto, Ornithodoros puertoricensis, Ornithodoros rioplatensis, Ornithodoros guaporensis and Ornithodoros hasei, all belonging to the O. talaje species group. The larval diagnostic characters for this species are a combination of a large pyriform dorsal plate with a length of approximately 300μm, 17 pairs of dorsal setae with five central pairs, hypostome with apex pointed and dental formula 2/2 in most rows, 3/3 apically, and capsule of the Haller's organ oval in shape without reticulations. Phylogenetic analyses inferred from the mitochondrial 16S rRNA gene and a Principal Component Analysis based on morphometric characters provide additional support to the description of O. atacamensis as an independent lineage within the genus clustering within the O. talaje species group.
Bosch, A E
The program 'Educacion y Trabajo' (Education and Work) in Chile was designed to help train unskilled workers and to facilitate their entrance into the labor market. Employing a participatory educational approach, the program provided personal and vocational training for men and women aged 15-30 years. Both technical and personal development training, which are embedded in Popular Education methodology, emphasize interaction among students and between students and teachers using games, videos, slides, manuals, cartoons, and worksheets. Interviews with female participants confirmed the program's empowering effects on the personal, as well as economic situation of women. The study further demonstrates how Popular Education is applied and adapted to promote self-esteem and self-reliance among female participants. Process-oriented, participatory learning, and horizontal relationships between the learner and teacher, allowed for the development of interactive structures in the classroom. This approach has especially benefited married women. Central to this empowerment process is awareness raising. By emphasizing the sociocultural origin of social structures, Popular Education helps demystify the social sphere and shows the importance of each individual in contributing to its improvement. However, while this program helps enhance women's self-esteem, self-confidence, and self-promotion, it only represents an initial step. To continue the path to full empowerment, negotiating powers must go beyond the household level and into the formal economy.
Dillehay, Tom D.; Ocampo, Carlos; Saavedra, José; Sawakuchi, Andre Oliveira; Vega, Rodrigo M.; Pino, Mario; Collins, Michael B.; Scott Cummings, Linda; Arregui, Iván; Villagran, Ximena S.; Hartmann, Gelvam A.; Mella, Mauricio; González, Andrea; Dix, George
Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia. PMID:26580202
Dillehay, Tom D; Ocampo, Carlos; Saavedra, José; Sawakuchi, Andre Oliveira; Vega, Rodrigo M; Pino, Mario; Collins, Michael B; Scott Cummings, Linda; Arregui, Iván; Villagran, Ximena S; Hartmann, Gelvam A; Mella, Mauricio; González, Andrea; Dix, George
Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia.
Haas, J; Olivares, M A; Palma-Behnke, R
Hydropeaking operations can severely degrade ecosystems. As variable renewable sources (e.g. wind power) are integrated into a power grid, fluctuations in the generation-demand balance are expected to increase. In this context, compensating technologies, notably hydropower reservoir plants, could operate in a stronger peaking scheme. This issue calls for an integrated modeling of the entire power system, including not only hydropower reservoirs, but also all other plants. A novel methodology to study the link between the short-term variability of renewable energies and the subdaily hydrologic alteration, due to hydropower reservoir operations is presented. Grid operations under selected wind power portfolios are simulated using a short-term hydro-thermal coordination tool. The resulting turbined flows by relevant reservoir plants are then compared in terms of the Richard-Baker flashiness index to both the baseline and the natural flow regime. Those are then analyzed in order to: i) detect if there is a significant change in the degree of subdaily hydrologic alteration (SDHA) due to a larger wind penetration, and ii) identify which rivers are most affected. The proposed scheme is applied to Chile's Central Interconnect System (SIC) for scenarios up to 15% of wind energy penetration. Results show a major degree of SDHA under the baseline as compared to the natural regime. As wind power increases, so does the SDHA in two important rivers. This suggests a need for further ecological studies in those rivers, along with an analysis of operational constraints to limit the SDHA.
Simonsen, Lone; Flores, Jose; Miller, Mark A.; Viboud, Cécile
Scarce information about the epidemiology of historical influenza pandemics in South America prevents complete understanding of pandemic patterns throughout the continent and across different climatic zones. To fill gaps with regard to spatiotemporal patterns of deaths associated with the 1918 influenza pandemic in Chile, we reviewed archival records. We found evidence that multiple pandemic waves at various times of the year and of varying intensities occurred during 1918–1921 and that influenza-related excess deaths peaked during July–August 1919. Pandemic-associated mortality rates were elevated for all age groups, including for adults >50 years of age; elevation from baseline was highest for young adults. Overall, the rate of excess deaths from the pandemic was estimated at 0.94% in Chile, similar to rates reported elsewhere in Latin America, but rates varied ≈10-fold across provinces. Patterns of death during the pandemic were affected by variation in host-specific susceptibility, population density, baseline death rate, and climate. PMID:25341056
Martínez, Jessica; Leal, Germán; Conget, Paulette
The microsporidian Nosema apis and Nosema ceranae have been associated with colony disorders of Apis mellifera and Apis cerana, respectively. N. apis is endemic in South America. Recently, N. ceranae has been detected in Brazil, Uruguay and Argentina. No report of its presence, distribution and prevalence in Chile is available. Here, we present a real-time PCR-based method that was able to discriminate between N. apis and N. ceranae. The dynamic range of this assay was 100 to 100,000 spores per honeybee. False-negative results were avoided due to the use of ACTIN gene as internal standard. False-positive results were obtained neither in experimentally nor in naturally contaminated samples. Using this method, we screened 240 beehives from the Chilean region where 42% of the total country honey production take places (Región del Biobío). Nosema spp. were detected in the four provinces and in 20 of the 26 communes of the region. Among the samples analysed, 49% were positive for N. ceranae. Their infection level ranged from 200 to more than 100,000 spores per honeybee. N. apis was not detected in this region. Hence, our data show that in Chile N. ceranae is an emergent pathogen that is been replacing N. apis. Also, they support that N. ceranae maybe the actual responsible for nosemosis in A. mellifera in South America.
Oerder, Véra; Colas, Francois; Echevin, Vincent; Codron, Francis; Tam, Jorge; Belmadani, Ali
The consequences of global warming on the Peru-Chile Current System (PCCS) ocean circulation are examined with a high-resolution, eddy-resolving regional oceanic model. We performed a dynamical downscaling of climate scenarios from the IPSL-CM4 Coupled General Circulation Model (CGCM), corresponding to various levels of CO2 concentrations in the atmosphere. High-resolution atmospheric forcing for the regional ocean model are obtained from the IPSL atmospheric model run on a stretched grid with increased horizontal resolution in the PCCS region. When comparing future scenarios to preindustrial (PI) conditions, the circulation along the Peru and Chile coasts is strongly modified by changes in surface winds and increased stratification caused by the regional warming. While the coastal poleward undercurrent is intensified, the surface equatorial coastal jet shoals and the nearshore mesoscale activity are reinforced. Reduction in alongshore wind stress and nearshore wind stress curl drive a year-round reduction in upwelling intensity off Peru. Modifications in geostrophic circulation mitigate this upwelling decrease in late austral summer. The depth of the upwelling source waters becomes shallower in warmer conditions, which may have a major impact on the system's biological productivity.
From 1984, when the first case of AIDS was diagnosed in Chile, to December 2003, 6.060 patients with AIDS and 6.514 with asymptomatic HIV infection have been notified to a passive national surveillance system; around 3,800 have died due to the infection. Magnitude of the under reporting is discussed. Assumed routes of the infection have been: sexual (94.1%), blood--largely intravenous drug use--(4.3%) and vertical transmission (1.6%). According to analysis performed by the National Commission on AIDS (CONASIDA), a governmental office, HIV/AIDS epidemic in Chile is characterized by: predominance in male homo/bisexuals, urban and rural distribution, impoverishment of the affected people, diagnosis made mainly during adulthood and a steady trend to affecting more women and heterosexuals at large. Since 2001 there has been a continuous increase in access to standard antiretroviral therapy (HAART) for those cared for by the public health system, reaching free coverage for 100% of this population by 2003, which has determined a significant decrease in the rate AIDS-associated clinical manifestations while reaching an stop of the previously increasing lethality of the infection (from a 15% increase from 1993-1997 to 0.2% from 1998-2003).
Cruz-Coke, R; Moreno, R S
We have studied the correlation between the ethnic structure and the prevalence of single gene defects in Chile. At present the Chilean population is approximately 64% white and 35% Amerindian with traces of other admixture. Fewer than 4% of the Chilean population are foreign born. Investigations indicate that all severe diseases and many others without impaired reproduction have mutation rates within the range of the white population. Classical ethnic diseases are very rare. Autosomal recessive disorders have a wide range of variability: cystic fibrosis has a low incidence and PKU has a similar incidence to English rates. Only 30% of the inborn errors of metabolism have been described in Chilean medical publications. In addition, no Chilean haemoglobin or haptoglobin variants have been described. Some rare inherited diseases in Chilean human isolates have been described, including achromatopsia, chondrocalcinosis, and Creutzfeldt-Jakob disease. The prevalence of intrahepatic cholestasis of pregnancy and supernumerary nipples is the highest in the world and they are associated with aboriginal origin. Single gene defects in Chile are probably shaped by factors related to its ethnic population structure. These local rare single gene defects may be good markers of population admixture for genetic epidemiological studies. PMID:7815439
Casas, Lidia; Vivaldi, Lieta
This article examines, from a human rights perspective, the experience of women, and the practices of health care providers regarding abortion in Chile. Most abortions, as high as 100,000 a year, are obtained surreptitiously and clandestinely, and income and connections play a key role. The illegality of abortion correlates strongly with vulnerability, feelings of guilt and loneliness, fear of prosecution, physical and psychological harm, and social ostracism. Moreover, the absolute legal ban on abortion has a chilling effect on health care providers and endangers women's lives and health. Although misoprostol use has significantly helped to prevent greater harm and enhance women's agency, a ban on sales created a black market. Against this backdrop, feminists have taken action in aid of women. For instance, a feminist collective opened a telephone hotline, Linea Aborto Libre (Free Abortion Line), which has been crucial in informing women of the correct and safe use of misoprostol. Chile is at a crossroads. For the first time in 24 years, abortion law reform seems plausible, at least when the woman's life or health is at risk and in cases of rape and fetal anomalies incompatible with life. The political scenario is unfolding as we write. Congressional approval does not mean automatic enactment of a new law; a constitutional challenge is highly likely and will have to be overcome.
Steubing, Bernhard; Böni, Heinz; Schluep, Mathias; Silva, Uca; Ludwig, Christian
The quantities of e-waste are expected to increase sharply in Chile. The purpose of this paper is to provide a quantitative data basis on generated e-waste quantities. A material flow analysis was carried out assessing the generation of e-waste from computer equipment (desktop and laptop PCs as well as CRT and LCD-monitors). Import and sales data were collected from the Chilean Customs database as well as from publications by the International Data Corporation. A survey was conducted to determine consumers' choices with respect to storage, re-use and disposal of computer equipment. The generation of e-waste was assessed in a baseline as well as upper and lower scenarios until 2020. The results for the baseline scenario show that about 10,000 and 20,000 tons of computer waste may be generated in the years 2010 and 2020, respectively. The cumulative e-waste generation will be four to five times higher in the upcoming decade (2010-2019) than during the current decade (2000-2009). By 2020, the shares of LCD-monitors and laptops will increase more rapidly replacing other e-waste including the CRT-monitors. The model also shows the principal flows of computer equipment from production and sale to recycling and disposal. The re-use of computer equipment plays an important role in Chile. An appropriate recycling scheme will have to be introduced to provide adequate solutions for the growing rate of e-waste generation.
Rubilar-Rogers, David; Otero, Rodrigo A.; Yury-Yáñez, Roberto E.; Vargas, Alexander O.; Gutstein, Carolina S.
In Chile, the record of dinosaurs in Jurassic and Cretaceous sediments is often restricted to footprints, with few skeletal remains. Tetanuran theropods are known in the Upper Jurassic, and bones of titanosaur sauropods in the Late Cretaceous, including partial skeletons (e.g. Atacamatitan chilensis Kellner et al.). Also from the late Cretaceous, an ornithopod vertebra, a pair of theropod teeth and one tarsometatarsus of a gaviiform bird (Neogaeornis wetzeli Lambrecht) have been reported. The Cenozoic fossil record comprises abundant and well-preserved marine birds from Eocene and Miocene units, with a specially abundant record of Sphenisciformes and less frequently, Procellariiformes. There is an excellent Miocene-Pliocene record of other birds such as Odontopterygiformes, including the most complete skeleton ever found of a pelagornithid, Pelagornis chilensis Mayr and Rubilar-Rogers. Fossil birds are also known from Pliocene and Pleistocene strata. A remarkable collection of birds was discovered in lacustrine sediments of late Pleistocene age associated to human activity. The perspectives in the study of dinosaurs in Chile are promising because plenty of material stored in institutional collections is not described yet. The record of Chilean dinosaurs is relevant for understanding the dynamics and evolution of this group of terrestrial animals in the western edge of Gondwana, while Cenozoic birds from the Region may contribute to the understanding of current biogeography for instance, the effect of the emergence and establishment of the Humboldt Current.
Reyes B, Humberto; Andresen H, Max; Palma H, Joaquín
During the first semester of 2009 Revista Médica de Chile has received an increasing number of manuscripts. Close to 30% were rejected while most other are in the process of being improved by the authors after receiving criticisms by external peer reviewers and the editors. The time lag between acceptance and publication of manuscripts is on an average six months. During 2008, 10% of articles published were submitted by authors from countries other than Chile and most of them were printed in English. Impact factor and other indexes provided by the ISI Web of Knowledge showed a promising improvement in 2008. The International Advisory Committee and the National Editorial Committee were renewed, a new Section on Laboratory Medicine was incorporated and several minor changes were done in design and format, in the title page and the issues' content. The main problems to be faced relate to the increasing cost of editing and printing, with a reduction in commercial advertising historically contributed by the pharmaceutical industry. Another major concern is to stimulate governmental agencies, scientific societies and universities to establish a national independent registry of clinical trials, that should become a mandatory requisite for every manuscript submitted to Chilean medical journals, reporting clinical trials performed in the country; foreign manuscripts should document the satisfaction of an identical requisite in their original source.
Vogt, N.; Evans, M.; Aranda, J.; Gotta, V.; Monsalves, A.; Puebla, E.
In Chile, one of the developing countries in Latin-America, there are large social differences that persist between the richest and the poorest citizens. On the other hand, Chile has the advantage of a special and unique resource, the incomparably clear and dry skies in the desert of Atacama in the north of the country. This advantage is being exploited by the installation of large and powerful international observatories. However, the Chilean people's perception of this resource and the corresponding advantages for their country are still underdeveloped and rather poor. Therefore, we have been conducting successful outreach activities at all levels during the past few years, with special highlights during the International Year of Astronomy 2009, including participation of our undergraduate physics and astronomy students, the local media like newspapers, radio, and TV stations, talks and workshops in schools, popular talks for the general public, exhibitions, contests, and other multi-media efforts. We briefly describe these activities and outline the difference between our situation and that existing in developed countries like the USA.
García O, Maritza; Olea N, Andrea
In Chile, the first cases of AIDS were reported 23 years ago, and since then, through December 2006, 17.235 persons have been notified with HIV infection or AIDS1. To the year 2005, there have been 5.288 fatal cases of AIDS. The last available data indicates that notification rates for AIDS and HIV infection in 2006 were 2.5 and 4.5 per 100.000 inhabitants, respectively, and mortality rate for AIDS in 2005 was 2.4 per 100.000 inhabitants. Trend analysis shows a decline in the notification rate among men, both for HIV infection and AIDS, which could be a real decrease or a sub notification bias. In Chile, like in other countries of the region, variations in the epidemiologic pattern were observed considering age group, gender, educational level and geographic distribution of the population. Currently, the Chilean Ministry of Health has implemented both a surveillance and monitoring system on line, in order to improve the quality and opportunity of the information, therefore providing an important tool to HIV infection/AIDS prevention and control strategies.