124 research outputs found

    Modelos mentales : ejecutivos sector privado-publico en las ciudades de Talca-Chile y Lujan-Argentina

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    134 p.La presente investigación tiene por objetivo analizar y comparar desde una perspectiva descriptiva los Modelos Mentales de los ejecutivos pertenecientes a la ciudad de Lujan-Argentina y de Talca-Chile, ya sean tanto del sector privado como publico. Entendiendose como Modelos Mentales según Peter Senge, en su libro La Quinta Disciplina, a los supuestos hondamente arraigados, generalizaciones e imágenes que influyen sobre nuestro modo de comprender el mundo y actuar. Para tal motivo, fragmentaremos nuestro trabajo en las fases de: Fundamentación Teórica: Donde obtuvimos la información adecuada, a través de la revisión de bibliografía pertinente, apoyándonos en la Memoria de Grado titulada "Modelos Mentales Ejecutivos sector publico y privado de la ciudad de Talca", efectuada por los alumnos Gabriela Fuentes Moreno y Ariel Schleef Sommer de la Universidad de Talca, tomando como base dicha investigación para analizar comparativamente las diferencias sustanciales entre los Modelos Mentales de los ejecutivos de la ciudad de Lujan y Talca, según sean del sector publico y privado, donde llegamos a establecer similitudes y diferencias entre los ejecutivos Argentinos de la ciudad de Lujan y Chilenos de la ciudad de Talca. Fundamentación Empírica: Desarrollada con la realización de Prueba Piloto con el fin de adecuar los instrumentos a aplicar a la cultura Argentina. Estudio Descriptivo: Desarrollado con la aplicación de cinco instrumentos de medición de las variables mas relevantes (Aprendizaje, Autoridad, Delegación, Liderazgo y Liderazgo para sus Subordinados), donde establecimos en primera instancia similitudes y diferencias entre los ejecutivos de Lujan; y finalmente realizamos un análisis comparativo de los resultados de nuestro estudio con los de la Memoria anteriormente mencionada

    Simulación Numérica del Efecto de un Mecanismo de Estratificación de Aire en un Quemador de Alta Velocidad

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    In this work, staged air combustion in a high speed burner was analyzed by mean of numerical simulation in order to determine its effects on temperature distribution and pollutant chemical species formation such as CO and NOx. The simulations were achieved using the commercial software ANSYS FLUENT as a design tool to predict the behavior of the thermal system and to establish operation conditions with or without staged air. Eddy Dissipation model was used for combustion simulation, while k - ε Realizable and Discrete Ordinates models were utilized for turbulence and radiation simulation, respectively. Results show that staged air mechanism allows better flame stabilization, combustion reactions initiation and fuel-air mixing. The CO formation was different in reaction zone and NOx emissions were not significantly influenced by the staged air.En este trabajo se analizó por medio de simulación numérica el efecto de la estratificación de aire en un quemador de alta velocidad con el fin de determinar su efecto sobre la distribución de temperatura, la estabilidad de llama y la formación de especies químicas contaminantes como CO y NOx. Las simulaciones se realizaron utilizando el software comercial ANSYS FLUENT para predecir el comportamiento del sistema con y sin uso del mecanismo de suministro de aire por etapas. En cada simulación se empleó el modelo Eddy Dissipation para la combustión, mientras que los modelos k - ε Realizable y Ordenadas Discretas fueron usados para la simulación del flujo turbulento y la radiación, respectivamente. Los resultados muestran que el uso de un mecanismo para estratificar el aire favorece la estabilización de llama, la iniciación de las reacciones de combustión y el mecanismo de mezclado. La formación de CO presentó diferencias en la zona de reacción y las emisiones de NOx no fueron significativamente influenciadas por el mecanismo de estratificación de aire

    Magnesium Removal from an Aluminum A-332 Molten Alloy Using Enriched Zeolite with Nanoparticles of SiO 2

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    In order to improve the Mg removal from an A-380 molten alloy, mixtures of zeolite and SiO2 nanoparticles (SiO2(NPs)) were tested. Zeolite was enriched with 2.5, 5, 7.5, 10, or 12.5 wt-% of amorphous SiO2(NPs). The SiO2(NPs) and zeolite were mixed for 30 min in ethanol for each experiment and then dried in a furnace at 80°C for 12 h. The enriched zeolites were analyzed by scanning electron microscopy, transmission electron microscopy, and N2 gas adsorption analysis. The Mg removal was carried out injecting each mixture into the molten aluminum alloy at 750°C using argon. The Mg content of the molten alloy was measured after different periods of the injection time. Zeolites enriched with 2.5 and 5 wt-% of SiO2(NPs) were demonstrated to be the better mixtures, removing Mg from an initial content of 1.6 to a final content of 0.0002 and 0.0101 wt-%, respectively, in 45 min of injection

    Estimating the abundance of the critically endangered Baltic Proper harbour porpoise (Phocoena phocoena) population using passive acoustic monitoring

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    The SAMBAH project was funded by the LIFE+ program of the European Commission (LIFE08 NAT/S/000261) and co-funded by Bundesamt für Naturschutz, Germany (SAMBAH II 5 Vw/52602/2011-Mar 36032/66); Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit, Germany (COSAMM FKZ 0325238); Carlsbergfondet, Denmark (CF16-0861); European Association of Zoos and Aquaria, The Netherlands; Główny Inpektorat Ochrony Środowiska, Poland; Havs-och Vattenmyndigheten, Sweden; Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy, Poland; Japanese Science and Technology Agency-CREST, Japan (7620-7); Kolmårdens Djurpark, Sweden; Maailman Luonnon Säätiö (WWF) Suomen Rahasto, Finland; Miljøministeriet, Denmark; Miljø- og Fødevareministeriet, Denmark (SN 343/SN-0008); Narodowy Fundusz Ochrony Środowiska i Gospodarki Wodnej, Poland (561/2009/Wn-50/OP/RE-LF/D); Naturvårdsverket, Sweden; SNAK Ph.D. School, Aarhus University, Denmark (91147/365); Tampereen Särkänniemi Ltd., Finland; Turun ammattikorkeakoulu Oy, Finland; Uniwersytet Gdański, Poland; Wojewódzki Fundusz Ochrony Środowiska i Gospodarki Wodnej w Gdańsku, Poland; and Ympäristöministeriö, Finland.Knowing the abundance of a population is a crucial component to assess its conservation status and develop effective conservation plans. For most cetaceans, abundance estimation is difficult given their cryptic and mobile nature, especially when the population is small and has a transnational distribution. In the Baltic Sea, the number of harbour porpoises (Phocoena phocoena) has collapsed since the mid-20th century and the Baltic Proper harbour porpoise is listed as Critically Endangered by the IUCN and HELCOM; however, its abundance remains unknown. Here, one of the largest ever passive acoustic monitoring studies was carried out by eight Baltic Sea nations to estimate the abundance of the Baltic Proper harbour porpoise for the first time. By logging porpoise echolocation signals at 298 stations during May 2011-April 2013, calibrating the loggers' spatial detection performance at sea, and measuring the click rate of tagged individuals, we estimated an abundance of 71-1105 individuals (95% CI, point estimate 491) during May-October within the population's proposed management border. The small abundance estimate strongly supports that the Baltic Proper harbour porpoise is facing an extremely high risk of extinction, and highlights the need for immediate and efficient conservation actions through international cooperation. It also provides a starting point in monitoring the trend of the population abundance to evaluate the effectiveness of management measures and determine its interactions with the larger neighboring Belt Sea population. Further, we offer evidence that design-based passive acoustic monitoring can generate reliable estimates of the abundance of rare and cryptic animal populations across large spatial scales.Publisher PDFPeer reviewe

    Oxr1 Is Essential for Protection against Oxidative Stress-Induced Neurodegeneration

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    Oxidative stress is a common etiological feature of neurological disorders, although the pathways that govern defence against reactive oxygen species (ROS) in neurodegeneration remain unclear. We have identified the role of oxidation resistance 1 (Oxr1) as a vital protein that controls the sensitivity of neuronal cells to oxidative stress; mice lacking Oxr1 display cerebellar neurodegeneration, and neurons are less susceptible to exogenous stress when the gene is over-expressed. A conserved short isoform of Oxr1 is also sufficient to confer this neuroprotective property both in vitro and in vivo. In addition, biochemical assays indicate that Oxr1 itself is susceptible to cysteine-mediated oxidation. Finally we show up-regulation of Oxr1 in both human and pre-symptomatic mouse models of amyotrophic lateral sclerosis, indicating that Oxr1 is potentially a novel neuroprotective factor in neurodegenerative disease

    The Dark Energy Survey Supernova Program: Corrections on Photometry Due to Wavelength-dependent Atmospheric Effects

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    Wavelength-dependent atmospheric effects impact photometric supernova flux measurements for ground-based observations. We present corrections on supernova flux measurements from the Dark Energy Survey Supernova Program’s 5YR sample (DES-SN5YR) for differential chromatic refraction (DCR) and wavelength-dependent seeing, and we show their impact on the cosmological parameters w and Ωm . We use g − i colors of Type Ia supernovae to quantify astrometric offsets caused by DCR and simulate point-spread functions (PSFs) using the GalSIM package to predict the shapes of the PSFs with DCR and wavelength-dependent seeing. We calculate the magnitude corrections and apply them to the magnitudes computed by the DES-SN5YR photometric pipeline. We find that for the DES-SN5YR analysis, not accounting for the astrometric offsets and changes in the PSF shape cause an average bias of +0.2 mmag and −0.3 mmag, respectively, with standard deviations of 0.7 mmag and 2.7 mmag across all DES observing bands (griz) throughout all redshifts. When the DCR and seeing effects are not accounted for, we find that w and Ωm are lower by less than 0.004 ± 0.02 and 0.001 ± 0.01, respectively, with 0.02 and 0.01 being the 1σ statistical uncertainties. Although we find that these biases do not limit the constraints of the DES-SN5YR sample, future surveys with much higher statistics, lower systematics, and especially those that observe in the u band will require these corrections as wavelength-dependent atmospheric effects are larger at shorter wavelengths. We also discuss limitations of our method and how they can be better accounted for in future surveys

    Age-related immune response heterogeneity to SARS-CoV-2 vaccine BNT162b2

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    Although two-dose mRNA vaccination provides excellent protection against SARS-CoV-2, there is little information about vaccine efficacy against variants of concern (VOC) in individuals above eighty years of age1. Here we analysed immune responses following vaccination with the BNT162b2 mRNA vaccine2 in elderly participants and younger healthcare workers. Serum neutralization and levels of binding IgG or IgA after the first vaccine dose were lower in older individuals, with a marked drop in participants over eighty years old. Sera from participants above eighty showed lower neutralization potency against the B.1.1.7 (Alpha), B.1.351 (Beta) and P.1. (Gamma) VOC than against the wild-type virus and were more likely to lack any neutralization against VOC following the first dose. However, following the second dose, neutralization against VOC was detectable regardless of age. The frequency of SARS-CoV-2 spike-specific memory B cells was higher in elderly responders (whose serum showed neutralization activity) than in non-responders after the first dose. Elderly participants showed a clear reduction in somatic hypermutation of class-switched cells. The production of interferon-γ and interleukin-2 by SARS-CoV-2 spike-specific T cells was lower in older participants, and both cytokines were secreted primarily by CD4 T cells. We conclude that the elderly are a high-risk population and that specific measures to boost vaccine responses in this population are warranted, particularly where variants of concern are circulating

    Artificial reefs built by 3D printing: Systematisation in the design, material selection and fabrication

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    The recovery of degraded marine coasts and the improvement of natural habitats are current issues of vital importance for the development of life, both marine and terrestrial. In this sense, the immersion of artificial reefs (ARs) in the marine environment is a way to stimulate the recovery of these damaged ecosystems. But it is necessary to have a multidisciplinary approach that analyses the materials, designs and construction process of artificial reefs in order to understand their true impact on the environment. For this reason, this paper presents the manufacture of artificial reefs by 3D printing, proposing designs with a combination of prismatic and random shapes, with different external overhangs as well as inner holes. For the definition of the artificial reef designs, criteria provided by marine biologists and the results obtained from a numerical simulation with ANSYS were taken into account, with which the stability of the artificial reefs on the seabed was analysed. Three dosages of cement mortars and three dosages of geopolymer mortars were studied as impression materials. The studies included determination of the rheological properties of the mortars, to define the printability, determination of the cost of the materials used, and determination of the mechanical strength and biological receptivity in prismatic specimens that were immersed in the sea for 3 months. To evaluate the environmental impact of the materials used in the production of the mortars, a Life Cycle Assessment (LCA) was carried out. In order to choose the mortars that encompassed the best properties studied, Multi-Criteria Decision Making (MCDM) was applied and the two best mortars were used for the manufacture of the artificial reefs. Finally, the advantages and disadvantages of the 3D printing process used were analysed. The results of the studies carried out in this research show that cement mortars have better characteristics for artificial reef applications using 3D printing, and that the technique applied for the manufacture of the artificial reefs allowed the digital models to be faithfully reproduced

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

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