Fluid geochemistry and seismic activityin the period 1998-2002 at Turrialba Volcano (Costa Rica)

Turrialba Volcano, located in Central-Southern Costa Rica, has been characterized, since the last period of eruptive activity in 1884-1886, by a weak and discontinuous fumarolic activity in the western area of its summit. During the 1998-2002 period, fumaroles discharging from central and West craters were collected for chemical analyses of major and trace gas compounds, 13C/12C in CO2 and 18O/16O and D/H (in one fumarolic condensate), isotopic ratios. Geophysical measurements (seismic activity and ground deformation), monitored in the same period, were compared to geochemical data to define the status of the volcanic system. Chemical and isotopic characteristics of fumaroles of Turrialba Volcano seem to be related to interaction processes between a magmatic source and a shallower hydrothermal aquifer. Since February 1997, seismicity at Turrialba Volcano gradually increased, while since August 2001 new fumaroles start to discharge from a new fracture system located in the area between central and West craters. Since September 2001, strong compositional changes of gas discharges have been recorded at central crater. These occurrences are possibly due to variations in the permeability of the conduit system feeding the fumaroles. Heat pulse episodes from a magmatic source have possibly caused the increase of vapour pressure at depth and, consequently, favoured the uprising of the magmatic fluids toward the surface. The observed evolution of chemical and physical parameters suggests that to forecast a possible renewal of the volcanic activity in the near future a full program of both geochemical and geophysical surveillance must be provided at Turrialba Volcano

Cosmology with interaction in the dark sector

Unless some unknown symmetry in Nature prevents or suppresses a non-minimal coupling in the dark sector, the dark energy field may interact with the pressureless component of dark matter. In this paper, we investigate some cosmological consequences of a general model of interacting dark matter-dark energy characterized by a dimensionless parameter $\epsilon$. We derive a coupled scalar field version for this general class of scenarios and carry out a joint statistical analysis involving SNe Ia data ({Legacy} and {Constitution} sets), measurements of baryon acoustic oscillation peak at $z = 0.20$ (2dFGRS) and $z = 0.35$ (SDSS), and measurements of the Hubble evolution $H(z)$. For the specific case of vacuum decay ($w = -1$), we find that, although physically forbidden, a transfer of energy from dark matter to dark energy is favored by the data.Comment: 5 pages, 5 figures, LaTe

Scalar field description of a parametric model of dark energy

We investigate theoretical and observational aspects of a time-dependent parameterization for the dark energy equation of state (EoS) $w(z)$, which is a well behaved function of the redshift $z$ over the entire cosmological evolution, i.e., $z \in [-1,\infty)$. By using a theoretical algorithm of constructing the quintessence potential directly from the effective EoS parameter, we derive and discuss the general features of the resulting potential for this $w(z)$ function. Since the parameterization here discussed allows us to divide the parametric plane in defined regions associated to distinct classes of dark energy models, we use the most recent observations from type Ia supernovae, baryon acoustic oscillation peak and Cosmic Microwave Background shift parameter to check which class is observationally prefered. We show that the largest portion of the confidence contours lies into the region corresponding to a possible crossing of the so-called phanton divide line at some point of the cosmic evolution.Comment: 5 pages, 2 figures, LaTe

Distance Functions and Normalization Under Stream Scenarios

Data normalization is an essential task when modeling a classification system. When dealing with data streams, data normalization becomes especially challenging since we may not know in advance the properties of the features, such as their minimum/maximum values, and these properties may change over time. We compare the accuracies generated by eight well-known distance functions in data streams without normalization, normalized considering the statistics of the first batch of data received, and considering the previous batch received. We argue that experimental protocols for streams that consider the full stream as normalized are unrealistic and can lead to biased and poor results. Our results indicate that using the original data stream without applying normalization, and the Canberra distance, can be a good combination when no information about the data stream is known beforehand.Comment: Paper accepted to the 2023 International Joint Conference on Neural Network

The zooarchaeological record of the North stretch of Middle Paraná River, left margin (Corrientes, Argentina)

En este trabajo se integran los datos obtenidos a partir del análisis macroscópico del material faunístico recuperado en posición estratigráfica en cinco sitios emplazados en la llanura aluvial del Paraná Medio (Corrientes, Argentina). El mismo constituye una síntesis de lo realizado hasta el momento sobre esta ergología para los sitios estudiados. En esta instancia el objetivo del análisis fue generar información respecto de los procesos involucrados en la formación de los depósitos estudiados y las evidencias concretas de la acción antrópica en su composición, así como también evaluar la variabilidad del registro arqueofaunístico depositado a lo largo del bloque espacio-tiempo bajo estudio. Los resultados obtenidos permiten sostener que los agentes físicos y químicos asociados a la dinámica de un ambiente marcadamente hidrófilo limitaron en gran parte las observaciones y líneas de análisis que se pueden desarrollar. A pesar de esto, las evidencias de acción antrópica permiten sostener el origen cultural de los conjuntos estudiados. Estas dan cuenta de la explotación y procesamiento de animales acuáticos junto a ciertas especies terrestres con algún grado de dependencia del medio acuático propias de este ambiente; taxa que presentan poco riesgo de obtención dada su profusión, diversidad y presencia respecto al ciclo ecológico. La información así generada permitió considerar el área trabajada a la luz de los modelos propuestos para interpretar el registro arqueológico del Paraná Medio.This paper presents a summary of the macroscopic analysis of faunal material recovered from five archaeological sites located in Middle Paraná alluvial plain (Corrientes, Argentina). The aim of this work is to understand the formation processes, especially regarding evidence of anthropic modifications, as well as to evaluate the variability within the zooarchaeological assemblages studied. The results show that physical and chemical constraints of a seasonally wet humid subtropical environment were the main agents that caused limitations of data sets. Nevertheless, anthropic modifications support that the faunal record is product of human action. Through the information presented, it is possible to record a whole use of a wide range of taxa, with a highlighted exploitation of aquatic animals together with some land animals with a certain grade of dependence to aquatic environment; taxa that are available throughout the year. Generalizations of the archeological record from Middle Paraná River were considered in the data interpretation.

Uso actual y potencial de aguas residuales domésticas (ARD) para irrigación en la provincia de Salta, Argentina

En este trabajo se presenta un relevamiento de las principales experiencias actuales de reutilización de aguas residuales domésticas (ARD) para irrigación en la provincia de Salta, Argentina. Se identificaron tres experiencias de reúso directo y cuatro experiencias de reúso indirecto de ARD para irrigación. Las mismas se localizan en inmediaciones a los sistemas de tratamiento de líquidos cloacales. La calidad microbiológica de los efluentes indica que ningún caso cumple con las directrices propuestas por la OMS para riego irrestricto y de áreas verdes. Se estima que el potencial de reúso con ARD en la provincia asciende a unas 3500 hectáreas, considerando cultivos de referencia según la localidad. Esta estimación debe ser complementada con estudios de factibilidad para cada caso en particular. Los resultados obtenidos representan un aporte para el reconocimiento y la validación de las aguas residuales como un recurso hídrico alternativo para la región.Fil: Salas Barboza, Ariela Griselda Judith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; ArgentinaFil: Gatto D'andrea, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; ArgentinaFil: Garces, V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; ArgentinaFil: Rodriguez Alvarez, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; ArgentinaFil: Liberal, Viviana Isabel. Universidad Nacional de Salta; ArgentinaFil: Paoli, H.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Seghezzo, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentin

The nasal delivery of nanoencapsulated statins – An approach for brain delivery

© 2016 Clementino et al. Purpose: Along with their cholesterol-lowering effect, statins have shown a wide range of pleiotropic effects potentially beneficial to neurodegenerative diseases. However, such effects are extremely elusive via the conventional oral administration. The purpose of the present study was to prepare and characterize the physicochemical properties and the in vivo biodistribution of simvastatin-loaded lecithin/chitosan nanoparticles (SVT-LCNs) suitable for nasal administration in view of an improved delivery of the statins to the brain. Materials and methods: Chitosan, lecithin, and different oil excipients were used to prepare nanocapsules loaded with simvastatin. Particle size distribution, surface charge, structure, simvastatin loading and release, and interaction with mucus of nanoparticles were determined. The nanoparticle nasal toxicity was evaluated in vitro using RPMI 2651 nasal cell lines. Finally, in vivo biodistribution was assessed by gamma scintigraphy via Tc99m labeling of the particles. Results: Among the different types of nanoparticles produced, the SVT-LCN_MaiLab showed the most ideal physicochemical characteristics, with small diameter (200 nm), positive surface charge (+48 mV) and high encapsulation efficiency (EE; 98%). Size distribution was further confirmed by nanoparticle tracking analysis and electron microscopy. The particles showed a relatively fast release of simvastatin in vitro (35.6%±4.2% in 6 hours) in simulated nasal fluid. Blank nanoparticles did not show cytotoxicity, evidencing that the formulation is safe for nasal administration, while cytotoxicity of simvastatin-loaded nanoparticles (IC50) was found to be three times lower than the drug solution (9.92 vs 3.50 μM). In rats, a significantly higher radioactivity was evidenced in the brain after nasal delivery of simvastatin-loaded nanoparticles in comparison to the administration of a similar dose of simvastatin suspension. Conclusion: The SVT-LCNs developed presented some of the most desirable characteristics for mucosal delivery, that is, small particle size, positive surface charge, long-term stability, high EE, and mucoadhesion. In addition, they displayed two exciting features: First was their biodegradability by enzymes present in the mucus layer, such as lysozyme. This indicates a new Trojan-horse strategy which may enhance drug release in the proximity of the nasal mucosa. Second was their ability to enhance the nose-to-brain transport as evidenced by preliminary gamma scintigraphy studies