Ab initio spectroscopic characterization of the radical CH3_3OCH2_2 at low temperatures

Spectroscopic and structural properties of methoxymethyl radical (CH$_3$OCH$_2$, RDME) are determined using explicitly correlated ab initio methods. This radical of astrophysical and atmospheric relevance has not been fully characterized at low temperatures, which has delayed the astrophysical searches. We provide rovibrational parameters, excitations to the low energy electronic states, torsional and inversion barriers and low vibrational energy levels. In the electronic ground state (X$^2$A), which appears "clean" from non-adiabatic effects, the minimum energy structure is an asymmetric geometry which rotational constants and dipole moment have been determined to be A$_0$=46718.6745 MHz, B$_0$=10748.4182 MHz, and C$_0$=9272.5105 MHz, and 1.432 D ($\mu_A$=0.6952 D, $\mu_B$=1.215 D, $\mu_C$=0.3016 D), respectively. A variational procedure has been applied to determine torsion-inversion energy levels. Each level splits into 3 subcomponents (A$_1$/A$_2$ and E) corresponding to the three methyl torsion minima. Although the potential energy surface presents 12 minima, at low temperatures, the infrared band shapes correspond to a surface with only three minima because the top of the inversion V$^{\alpha}$ barrier at ${\alpha}=0^{\circ}$ (109 cm$^{-1}$) stands below the zero point vibrational energy and the CH$_2$ torsional barrier is relatively high ($\sim$2000 cm$^{-1}$). The methyl torsion barrier was computed to be $\sim$500 cm$^{-1}$ and produces a splitting of 0.01 cm$^{-1}$ of the ground vibrational state

Extracellular ferritin contributes to neuronal injury in an in vitro model of ischemic stroke

Previous clinical and experimental studies have shown that neurological decline and poor functional outcome after acute ischemic stroke in humans are associated with high ferritin levels in serum and cerebrospinal fluid (CSF) within 24 h of ischemic stroke onset. The aim of the present study was to find out if and how high extracellular ferritin concentrations can increase the excitotoxicity effect in a neuronal cortical culture model of stroke. Extracellular ferritin (100 ng/ml) significantly increased the excitotoxic effect caused by excessive exogenous glutamate (50 µM and 100 µM) by leading to an increase in lipid peroxidation, a reduction in mitochondrial membrane potential, and a decrease in neuron viability. Extracellular apoferritin (100 ng/ml), the iron-free form of the protein, does not increase the excitotoxicity of glutamate, which proves that iron was responsible for the neurotoxic effect of the exogenous ferritin. We present evidence that extracellular ferritin iron exacerbates the neurotoxic effect induced by glutamate excitotoxicity and that the effect of ferritin iron is dependent of glutamate excitotoxicity. Our results support the idea that body iron overload is involved in the severity of the brain damage caused by stroke and reveal the need to control systemic iron homeostasis.Peer ReviewedPostprint (author's final draft

Numerical study of the aerodynamics of sound sources in a bass-reflex port

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The aim of this paper is to study the aerodynamics phenomena of a bass-reflex port that causes noise in the audible frequency range. After discarding structural and mechanical vibration issues, the hypothesis considered is that vortex shedding is the source of the noise. Experimental and numerical evidences of the vortex, an analysis of its noise and the similarities between real and simulated performance are presented. The numerically simulated cases with the original geometry are excited at different frequencies and with modifications of the port geometry. Likewise, the internal performance of an enclosure with a closed port was simulated. The simulations have been performed with axisymmetrical geometries using the open-source OpenFOAM® toolbox. Moreover, experimental measurements were carried out. First, acoustic signal experiments were done to analyse the response of the bass-reflex ports. Secondly, a structure vibration measurement was conducted in order to exclude the cabinet structure vibration as a source of the noise in question. A good agreement was found between numerical and experimental results, especially in the frequency band of the detected noise, i.e. the 1000–1500 Hz range. Despite no remarkable improvement being made with the geometry changes explored, the presented CFD approach has proved a useful and cost-effective tool to address this kind of phenomenon.Peer ReviewedPostprint (published version

Renewable Energy Sources on the Change of Energy Matrix in Manabí Province

The exploitation, distribution, and consumption of energy have caused the greatest environmental pollution on the planet and accelerated climate change; even though it has been the promoter of the social, economic development of many generations. Contemporary man can continue to increase his social development, but looking for alternatives to energy development. The work shows a model of energy development that will guarantee the sustainability of social development in the areas of the province of Manabí where energy arrives with low quality and in other places does not exist. The objective of the work is to propose the diversification of the energy matrix from the gradual and progressive introduction of technologies based on the use of renewable resources that it has was distributed in the territory of the province. This result will allow the use of indigenous renewable resources, reduce environmental pollution, and improve the quality of life of populations based on the principle of energy sustainability

Local Development Applied to Energy Scheme

Manabí is a province with great potential, either in the agri-food sector or in the renewable generation of energy. However, the limitations inherited from traditional development models prevent achieving the sustainable development of this territory. This paper proposes a development model at the local level, aimed at achieving equity and, through the use of renewable energy sources and other potentials present in specific territories, to improve the quality of life and reduce the risks of societies present there. Through geographic information systems, it was possible to generate and display on maps information related to the energy demand at the provincial and cantonal levels, as well as the province's energy behavior considering the population density

Effects of Thermal Radiation Using Wood Stoves on Population Health

The use of biomass for cooking food in the rural sector of the province of Manabí is very common. The present work analyzes the situation of families that use wood stoves for the cooking of food in the community of Casas Viejas, canton Jipipapa, province of Manabí. Thermography techniques have used to measure the level of emissivity to which users of traditional kitchens are exposed. It was determined that the exposure is direct and reaches temperatures up to 250 ° C, being able to raise its body temperature in the abdominal area up to 80 ° C. This periodic and prolonged exposure to thermal radiation can seriously affect the health of users

Extracellular ferritin contributes to neuronal injury in an in vitro model of ischemic stroke

Previous clinical and experimental studies have shown that neurological decline and poor functional outcome after acute ischemic stroke in humans are associated with high ferritin levels in serum and cerebrospinal fluid (CSF) within 24 hours of ischemic stroke onset. The aim of the present study was to find out if and how high extracellular ferritin concentrations can increase the excitotoxicity effect in a neuronal cortical culture model of stroke. Extracellular ferritin (100 ng/ml) significantly increased the excitotoxic effect caused by excessive exogenous glutamate (50 µM and 100 µM) by leading to an increase in lipid peroxidation, a reduction in mitochondrial membrane potential and a decrease in neuron viability. Extracellular apoferritin (100 ng/ml), the iron-free form of the protein, does not increase the excitotoxicity of glutamate, which proves that iron was responsible for the neurotoxic effect of the exogenous ferritin. We present evidence that extracellular ferritin iron exacerbate the neurotoxic effect induced by glutamate excitotoxicity and that the effect of ferritin iron is dependent of glutamate excitotoxicity. Our results support the idea that body iron overload is involved in the severity of the brain damage caused by stroke and reveal the need to control systemic iron homeostasis

Management Model For University Cooperation At Universidad Técnica De Manabí, Ecuador

In researching a management model for university cooperation at the Universidad Técnica de Manabí, with its components, phases, stages, input, and output information as well as the premises of its practical application, thereby achieving qualitative and quantitative changes proposed in the conception of university cooperation for sustainable development. The model for the management of cooperation, the assumptions of the model and the components are exposed, and a map with universities that are currently on the network and the issues raised in the strategy, setting out the results at national and International levels

Luminosity-Metallicity Relation for dIrr Galaxies in the Near-Infrared

(abridged) The present work is a first step to collect homogeneous abundances and near-infrared (NIR) luminosities for a sample of dwarf irregular (dIrr) galaxies, located in nearby groups. The use of NIR luminosities is intended to provide a better proxy to mass than the blue luminosities commonly used in the literature; in addition, selecting group members reduces the impact of uncertain distances. Accurate abundances are derived to assess the galaxy metallicity. Optical spectra are collected for Hii regions in the dIrrs, allowing the determination of oxygen abundances by means of the temperature-sensitive method. For each dIrr galaxy H-band imaging is performed and the total magnitudes are measured via surface photometry. This high-quality database allows us to build a well-defined luminosity-metallicity relation in the range -13 >= M(H) >= -20. The scatter around its linear fit is reduced to 0.11 dex, the lowest of all relations currently available. There might exist a difference between the relation for dIrrs and the relation for giant galaxies, although a firm conclusion should await direct abundance determinations for a significant sample of massive galaxies. This new dataset provides an improved luminosity-metallicity relation, based on a standard NIR band, for dwarf star-forming galaxies. The relation can now be compared with some confidence to the predictions of models of galaxy evolution. Exciting follow-ups of this work are (a) exploring groups with higher densities, (b) exploring nearby galaxy clusters to probe environmental effects on the luminosity-metallicity relation, and (c) deriving direct oxygen abundances in the central regions of star-forming giant galaxies, to settle the question of a possible dichotomy between the chemical evolution of dwarfs and that of massive galaxies.Comment: 23 pages, 10 figures, accepted by A&