Corrección de errores de nivelación de datos aerogeofísicos

En el presente trabajo se realiza una mejora a la técnica de correlación línea a línea (line-to-line correlation) para la remoción de errores de nivelación de datos geofísicos obtenidos mediante prospección aérea. Esta técnica, bajo la hipótesis de continuidad y fuerte correlación de los registros de perfiles de líneas de vuelo adyacentes, logra la nivelación mediante la construcción de un filtro funcional mediante una ventana móvil en una dimensión. Se aplica este filtro línea a línea en forma recursiva logrando disminuir los errores de nivelación y ajustarlos en el sentido de los cuadrados mínimos. Nuestra mejora consiste en la implementación de la técnica mediante la aplicación de filtros n-dimensionales, sobre bases de sucesiones polinomiales ortogonales. El procedimiento utilizado consistió en la generación de datos sintéticos a los cuales se les introdujo errores de nivelación ad-hoc de diferentes características típicas para simular los encontrados en una aeroprospección real. Luego aplicamos la técnica con este método mejorado como si se tratase de datos reales y comparamos con los datos sintéticos sin error de nivelación. Hemos hallado los rangos en que las bases ortogonales de Legendre y Chebyshev mejoran notablemente la estabilidad y resultados de la técnica, respecto de la implementación usando la base canónica. Luego se ha aplicado la técnica mejorada a un registro aeromagnético real adquirido sobre el área volcánica del Archipiélago James Ross, en el Mar de Weddell, en el extremo nororiental de la Península Antártica, obteniendo un muy buen resultado en la remoción de los errores de nivelación de la prospección. La remoción efectiva de los errores de nivelación resulta de fundamental importancia para lograr obtener, a partir de la inversión de los datos, modelos consistentes y representativos de la realidad geofísica que intenta describirse.Eje: Geofísica Aplicada y Ambiental.Facultad de Ciencias Astronómicas y Geofísica

Expansion of magnetic clouds in the outer heliosphere

A large amount of magnetized plasma is frequently ejected from the Sun as coronal mass ejections (CMEs). Some of these ejections are detected in the solar wind as magnetic clouds (MCs) that have flux rope signatures. Magnetic clouds are structures that typically expand in the inner heliosphere. We derive the expansion properties of MCs in the outer heliosphere from one to five astronomical units to compare them with those in the inner heliosphere. We analyze MCs observed by the Ulysses spacecraft using insitu magnetic field and plasma measurements. The MC boundaries are defined in the MC frame after defining the MC axis with a minimum variance method applied only to the flux rope structure. As in the inner heliosphere, a large fraction of the velocity profile within MCs is close to a linear function of time. This is indicative of} a self-similar expansion and a MC size that locally follows a power-law of the solar distance with an exponent called zeta. We derive the value of zeta from the insitu velocity data. We analyze separately the non-perturbed MCs (cases showing a linear velocity profile almost for the full event), and perturbed MCs (cases showing a strongly distorted velocity profile). We find that non-perturbed MCs expand with a similar non-dimensional expansion rate (zeta=1.05+-0.34), i.e. slightly faster than at the solar distance and in the inner heliosphere (zeta=0.91+-0.23). The subset of perturbed MCs expands, as in the inner heliosphere, at a significantly lower rate and with a larger dispersion (zeta=0.28+-0.52) as expected from the temporal evolution found in numerical simulations. This local measure of the expansion also agrees with the distribution with distance of MC size,mean magnetic field, and plasma parameters. The MCs interacting with a strong field region, e.g. another MC, have the most variable expansion rate (ranging from compression to over-expansion)

Calibration of the operative cosmic ray detector at Marambio Base in the Antarctic Peninsula

During 2019 an Antarctic Space Weather Laboratory was deployed at Marambio base in the Antarctic Peninsula. The main instrument installed was a cosmic ray detector based on water Cherenkov radiation (WCD). This detector is the first permanent Antarctic node of the LAGO (Latin American Giant Observatory) Collaboration. Long-term calibrated observations of the WCD will be presented here. Finally, the global galactic cosmic rays variability observed with the WCD will be compared with observations of a neutron monitor with similar rigidity cut off than the Marambio site

Low-Cost Heaving Single-Buoy Wave-Energy Point Absorber Optimization for Sardinia West Coast

This work presents the Water Energy Point Absorber (WEPA), which is a heaving single-buoy point absorber optimized for a specific site off the west coast of Sardinia Island. The aim of the study is to present the optimization process undertaken to identify the best configuration in terms of performance and cost. The optimization is carried out thanks to a simulation tool developed in Matlab-Simulink environment and verified through to the commercial software Orcaflex. Simulations are performed in the time domain with the installation site’s waves as input. The hydrodynamics parameters are computed thanks to the commercial software Ansys Aqwa and given to the model as input. The yearly energy production is computed as output for each configuration. Several parametric analyses are performed to identify the optimal Power Take Off (PTO) and buoy size. Among the main findings, it shall be mentioned that the PTO-rated torque has a strong influence on the energy production, higher PTO-rated torque proved to have better performance. The optimal hull size is strictly related to the incoming waves, and for the given site the smaller hulls are performing better than larger ones. The hull height, hull mass and hull draft have little impact on productivity. Finally, a comprehensive techno–economic analysis is performed, showing that the best configuration can be identified only after a detailed feasibility study and rigorous cost analysis

Alcohol-induced blood-brain barrier impairment: An in vitro study

In recent years, alcohol abuse has dramatically grown with deleterious consequence for people’s health and, in turn, for health care costs. It has been demonstrated, in humans and animals, that alcohol intoxication induces neuroinflammation and neurodegeneration thus leading to brain impairments. Furthermore, it has been shown that alcohol consumption is able to impair the blood– brain barrier (BBB), but the molecular mechanisms underlining this detrimental effect have not been fully elucidated. For this reason, in this study we investigated the effects of alcohol exposure on a rat brain endothelial (RBE4) cell line, as an in vitro-validated model of brain microvascular endothelial cells. To assess whether alcohol caused a concentration-related response, the cells were treated at different times with increasing concentrations (10–1713 mM) of ethyl alcohol (EtOH). Microscopic and molecular techniques, such as cell viability assay, immunofluorescence and Western blotting, were used to examine the mechanisms involved in alcohol-induced brain endothelial cell alterations including tight junction distribution, apoptosis, and reactive oxygen species production. Our findings clearly demonstrate that alcohol causes the formation of gaps between cells by tight junction disassembly, triggered by the endoplasmic reticulum and oxidative stress, highlighted by GRP78 chaperone upregulation and increase in reactive oxygen species production, respectively. The results from this study shed light on the mechanisms underlying alcohol-induced blood–brain barrier dysfunction and a better understanding of these processes will allow us to take advantage of developing new therapeutic strategies in order to prevent the deleterious effects of alcohol

Proteomic and carbonylation profile analysis of rat skeletal muscles following acute swimming exercise

Previous studies by us and other groups characterized protein expression variation following long-term moderate training, whereas the effects of single bursts of exercise are less known. Making use of a proteomic approach, we investigated the effects of acute swimming exercise (ASE) on protein expression and carbonylation patterns in two hind limb muscles: the Extensor Digitorum Longus (EDL) and the Soleus, mostly composed of fast-twitch and slow-twitch fibres, respectively. Carbonylation is one of the most common oxidative modifications of proteins and a marker of oxidative stress. In fact, several studies suggest that physical activity and the consequent increase in oxygen consumption can lead to increase in reactive oxygen and nitrogen species (RONS) production, hence the interest in examining the impact of RONS on skeletal muscle proteins following ASE. Results indicate that protein expression is unaffected by ASE in both muscle types. Unexpectedly, the protein carbonylation level was reduced following ASE. In particular, the analysis found 31 and 5 spots, in Soleus and EDL muscles respectively, whose carbonylation is reduced after ASE. Lipid peroxidation levels in Soleus were markedly reduced as well. Most of the decarbonylated proteins are involved either in the regulation of muscle contractions or in the regulation of energy metabolism. A number of hypotheses may be advanced to account for such results, which will be addressed in future studies

Cannabidiol protects dopaminergic neuronal cells from cadmium

The protective effect of cannabidiol (CBD), the non-psychoactive component of Cannabis sativa, against neuronal toxicity induced by cadmium chloride (CdCl2 10 μM) was investigated in a retinoic acid (RA)-differentiated SH-SY5Y neuroblastoma cell line. CBD (1 μM) was applied 24 h before and removed during cadmium (Cd) treatment. In differentiated neuronal cells, CBD significantly reduced the Cd-dependent decrease of cell viability, and the rapid reactive oxygen species (ROS) increase. CBD significantly prevented the endoplasmic reticulum (ER) stress (GRP78 increase) and the subcellular distribution of the cytochrome C, as well as the overexpression of the pro-apoptotic protein BAX. Immunocytochemical analysis as well as quantitative protein evaluation by western blotting revealed that CBD partially counteracted the depletion of the growth associated protein 43 (GAP43) and of the neuronal specific class III β-tubulin (β3 tubulin) induced by Cd treatment. These data showed that Cd-induced neuronal injury was ameliorated by CBD treatment and it was concluded that CBD may represent a potential option to protect neuronal cells from the detrimental effects of Cd toxicity