Time filter

Source Type

Concepcion, Chile

The University of Concepción , also known for its acronym UdeC, is one of the most prestigious universities in Chile. It is the third oldest university in the country and is part of the Council of Rectors. It was the first university founded in the south of Chile, and the first to become a private-law corporation. In addition, it belongs to the Southern Cross University Network .Its main campus is located at the Concepción's University City, with additional campuses in Chillán and Los Ángeles.The QS University Ranking 2012 ranks the University of Concepción as the ninth best in Latin America. The 2011 CSIC University Ranking named it as the second best in Chile and 19th best in Latin America, while business magazine America Economía's 2010 SIR Iberoamerican Ranking rates it as the nation’s number three university. Wikipedia.

Antezana T.,University of Concepcion
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2010

Euphausiids are important components of many ecosystems, especially in productive regions of temperate and high latitudes. The present paper makes the case that E. mucronata plays a keystone role in the food web of the Humboldt Current System (HCS) based on a synthesis of new and published data supporting its potential role as a primary grazer, as well as a principal prey for upper trophic level fish. E. mucronata is an endemic species, concentrated in the coastal upwelling belt of the HCS, with morpho-physiological adaptations to vertically migrate into the Oxygen Minimum Zone (OMZ). Within the 100-km coastal belt of the HCS it accounts for ca. 50% of the meso zooplankton wet weight in winter. In the mixed layer, it is a herbivore with high night ingestion rates (612.2 ng Chl eq ind-1 h-1 or 1013.9 μg C ind-1 d-1, in winter), and accounted for a 19.3% impact on primary production in winter, at an intermediate population abundance (3.8 ind m-3). At higher abundances (50 ind m-3) equivalent to swarms, impact on primary production could reach 254%. Additionally E. mucronata is a common prey of numerous upper trophic level predators. The diet of jack mackerel (Trachurus murphyi) off central Chile (34-39°S) indicates a striking dependence on E. mucronata prey (average of 75% of stomach content in weight). The fishing season off central Chile extended from austral fall (March-April) and continued at least until the end of austral winter (September). The average daily ration of jack mackerel was 17.4 g, which is equivalent to 2.3% of fish body weight per day. The total E. mucronata consumed in 1991 by the landed population of fish (3.7 million tons yr-1) amounted to 23.2 million tons yr-1. The total estimated population of jack mackerel that year (17.6 million tons) would have consumed ca. 110.2 million tons of E. mucronata. Based on stomach contents, consumption of E. mucronata by other nektonic predators off Chile and off Peru is also outstanding. Four different food web scenarios are offered for the northern and southern sectors of the HCS, according to regime shifts of small pelagics such as anchovy and jack mackerel, under the assumption that E. mucronata is a keystone link. © 2009 Elsevier Ltd. All rights reserved.

Barea J.,University of Concepcion | Kotila J.,Yale University | Iachello F.,Yale University
Physical Review Letters | Year: 2012

Neutrinoless double-β decay is of fundamental importance for the determining neutrino mass. By combining a calculation of nuclear matrix elements within the framework of the microscopic interacting boson model with an improved calculation of phase space factors, we set limits on the average light neutrino mass and on the average inverse heavy neutrino mass (flavor-violating parameter). © 2012 American Physical Society.

Tassara A.,University of Concepcion
Tectonophysics | Year: 2010

Unveiling how the interaction of friction (μ), pore pressure (p) and normal stress (σn) controls the shear strength distribution along megathrust faults at convergent plate boundaries is crucial to our understanding of processes leading to the occurrence of devastating earthquake and the construction of mountains. An existing density model of the Chilean margin (18°-45°S) allows the computation of the so-called Vertical Stress Anomaly (VSA) that accounts for the component of normal stress due to the weight of the overlying crustal column. A spatial correlation between VSA, surface geology and several earthquake parameters suggests a significant control exerted by the geologically-dominated density structure of the crust on megathrust shear strength. The very seismogenic forearc in front of the high Central Andes (18°-34°S) has positive VSA values (up to 60MPa) and a mafic-dominated crust, which suggest high values of shear strength at the megathrust that are partially controlled by the weight of a dense forearc crustal column, in addition to a likely dry subduction channel characterized by high-μ and low-p. In contrast, the Southern Andean forearc (34°-45°S) shows neutral-to-negative VSA (down to -30MPa) correlated with a felsic-dominated crust, which added to a presumably wet subduction channel (low-μ and high-p) configures a rather weak megathrust below a light forearc. Earthquakes here are concentrated around the Arauco peninsula, a first-order morpho-structural anomaly characterized by comparatively higher values of VSA than the rest of this segment, which is the nest of the giant (Mw 9.5) Valdivia 1960 earthquake and the southern rupture termination of the recent Mw 8.8 Maule earthquake. The ultimately giant size of the 1960 earthquake resulted from rupture propagation along a 1000km long region characterized by negative VSA values. The correlation between VSA and the along-strike segmentation of the Andean orogen indicates that the geologically-inherited density structure of the forearc also rules long-term mechanical coupling between converging plates and prescribes the possible structure of the orogen. Because Central and Southern Andes represent two extremes in terms of orogenic structure and seismogenic behavior, results presented here have significant implications for the general comprehension of processes occurring at short and long time scale at convergent margins. © 2010 Elsevier B.V.

Asenjo Lobos C.,University of Concepcion
Cochrane database of systematic reviews (Online) | Year: 2010

Clozapine is an atypical antipsychotic demonstrated to be superior in the treatment of refractory schizophrenia which causes fewer movement disorders. Clozapine, however, entails a significant risk of serious blood disorders such as agranulocytosis which could be potentially fatal. Currently there are a number of newer antipsychotics which have been developed with the purpose to find both a better tolerability profile and a superior effectiveness. To compare the clinical effects of clozapine with other atypical antipsychotics (such as amisulpride, aripiprazole, olanzapine, quetiapine, risperidone, sertindole, ziprasidone and zotepine) in the treatment of schizophrenia and schizophrenia-like psychoses. We searched the Cochrane Schizophrenia Groups Register (June 2007) and reference lists of all included randomised controlled trials. We also manually searched appropriate journals and conference proceedings relating to clozapine combination strategies and contacted relevant pharmaceutical companies. All relevant randomised, at least single-blind trials, comparing clozapine with other atypical antipsychotics, any dose and oral formulations, for people with schizophrenia or related disorders. We selected trials and extracted data independently. For dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) based on a random-effects model. We calculated numbers needed to treat/harm (NNT/NNH) where appropriate. For continuous data, we calculated mean differences (MD) again based on a random-effects model. The review currently includes 27 blinded randomised controlled trials, which involved 3099 participants. Twelve randomised control trials compared clozapine with olanzapine, five with quetiapine, nine with risperidone, one with ziprasidone and two with zotepine. Attrition from these studies was high (overall 30.1%), leaving the interpretation of results problematic. Clozapine had a higher attrition rate due to adverse effects than olanzapine (9 RCTs, n=1674, RR 1.60 CI 1.07 to 2.40, NNT 25 CI 15 to 73) and risperidone (6 RCTs, n=627, RR 1.88 CI 1.11 to 3.21, NNT 16 CI 9 to 59). Fewer participants in the clozapine groups left the trials early due to inefficacy than risperidone (6 RCTs, n=627, RR 0.40 CI 0.23 to 0.70, NNT 11 CI 7 to 21), suggesting a certain higher efficacy of clozapine.Clozapine was more efficacious than zotepine in improving the participants general mental state (BPRS total score: 1 RCT, n=59, MD -6.00 CI -9.83 to -2.17), but not consistently more than olanzapine, quetiapine, risperidone and ziprasidone. There was no significant difference between clozapine and olanzapine or risperidone in terms of positive or negative symptoms of schizophrenia. According to two studies from China quetiapine was more efficacious for negative symptoms than clozapine (2 RCTs, n=142, MD 2.23 CI 0.99 to 3.48).Clozapine produced somewhat fewer extrapyramidal side-effects than risperidone (use of antiparkinson medication: 6 RCTs, n=304, RR 0.39 CI 0.22 to 0.68, NNT 7 CI 5 to 18) and zotepine (n=59, RR 0.05 CI 0.00 to 0.86, NNT 3 CI 2 to 5). More participants in the clozapine group showed decreased white blood cells than those taking olanzapine, more hypersalivation and sedation than those on olanzapine, risperidone and quetiapine and more seizures than people on olanzapine and risperidone. Also clozapine produced an important weight gain not seen with risperidone.Other differences in adverse effects were less documented and should be replicated, for example, clozapine did not alter prolactin levels whereas olanzapine, risperidone and zotepine did; compared with quetiapine, clozapine produced a higher incidence of electrocardiogram (ECG) alterations; and compared with quetiapine and risperidone clozapine produced a higher increase of triglyceride levels. Other findings that should be replicated were: clozapine improved social functioning less than risperidone and fewer participants in the clozapine group had to be hospitalised to avoid suicide attempts compared to olanzapine.Other important outcomes such as service use, cognitive functioning, satisfaction with care or quality of life were rarely reported. Clozapine may be a little more efficacious than zotepine and risperidone but further trials are required to confirm this finding. Clozapine differs more clearly in adverse effects from other second generation antipsychotics and the side-effect profile could be key in the selection of treatment depending on the clinical situation and a patient's preferences. Data on other important outcomes such as cognitive functioning, quality of life, death or service use are currently largely missing, making further large and well-designed trials necessary. It is also important to take into account that the large number of people leaving the studies early limits the validity and interpretation of our findings.

Muller E.A.,Imperial College London | Mejia A.,University of Concepcion
Journal of Physical Chemistry Letters | Year: 2014

Literature values regarding the pressure dependence of the interfacial tension of the system of carbon dioxide (CO2) + water (H 2O) show an unexplained divergence and scatter at the transition between low-pressure gas-liquid equilibrium and the high-pressure liquid-liquid equilibrium. We employ the Statistical Associating Fluid Theory (SAFT) and canonical molecular dynamics simulations based on the corresponding coarse grained force field to map out the phase diagram of the mixture and the interfacial tension for this system. We showcase how at ambient temperatures a triple point (gas-liquid-liquid) is expected and detail the implications that the appearance of the third phase has on the interfacial tensions of the system. © 2014 American Chemical Society.

Discover hidden collaborations