Estudio Hidrogeoquimico De Las Áreas Termales Del Complejo Volcánico Copahue-Caviahue

Hydrogeochemical study on Thermal areas of the Copahue-Caviahue Volcanic Complex The hydrothermal system hosted in the Copahue- Caviahue Volcanic Complex consists of different geothermal areas around the Copahue volcano, whose last eruptive cycle started on December 22 of 2012. This work presents new data from the samplings of November 2012 and march 2013 in Las Maquinas, Las Maquinitas, villa de Copahue and Chancho-Có areas. These acid-sulfate and steam heated waters, presented changes in their SO4-2 concentrations, especially in Las Maquinas and Las Maquinitas areas. Meanwhile, SO4-2/Cl- ratios presented a strong decrease in the samples from November 2012, regarding the samples from 2013. These values were corrected by the seasonal effect, and the observed differences remained. Rare Earth elements compositions on waters from these hotsprings are also presented

Investigating the structure and fragmentation of a highly filamentary IRDC

We present 3.7 arcsec (~0.05 pc) resolution 3.2 mm dust continuum observations from the IRAM PdBI, with the aim of studying the structure and fragmentation of the filamentary Infrared Dark Cloud G035.39-00.33. The continuum emission is segmented into a series of 13 quasi-regularly spaced (~0.18pc) cores, following the major axis of the IRDC. We compare the spatial distribution of the cores with that predicted by theoretical work describing the fragmentation of hydrodynamic fluid cylinders, finding a significant (factor of ~8) discrepancy between the two. Our observations are consistent with the picture emerging from kinematic studies of molecular clouds suggesting that the cores are harboured within a complex network of independent sub-filaments. This result emphasises the importance of considering the underlying physical structure, and potentially, dynamically important magnetic fields, in any fragmentation analysis. The identified cores exhibit a range in (peak) beam-averaged column density ($3.6{\rm x}10^{23}{\rm cm}^{-2}<N_{H,c}<8.0{\rm x}10^{23}{\rm cm}^{-2}$), mass ($8.1M_{\odot}<M_{c}<26.1M_{\odot}$), and number density ($6.1{\rm x}10^{5}{\rm cm}^{-3}<n_{H, c, eq}<14.7{\rm x}10^{5}{\rm cm}^{-3}$). Two of these cores, dark in the mid-infrared, centrally-concentrated, monolithic (with no traceable substructure at our PdBI resolution), and with estimated masses of the order ~20-25$M_{\odot}$, are good candidates for the progenitors of intermediate-to-high-mass stars. Virial parameters span a range $0.2<\alpha_{\rm vir}<1.3$. Without additional support, possibly from dynamically important magnetic fields with strengths of the order 230$\mu$G<B<670$\mu$G, the cores are susceptible to gravitational collapse. These results may imply a multi-layered fragmentation process, which incorporates the formation of sub-filaments, embedded cores, and the possibility of further fragmentation

Interstellar Plunging Waves: ALMA Resolves the Physical Structure of Nonstationary MHD Shocks

Magnetohydrodynamic (MHD) shocks are violent events that inject large amounts of energy in the interstellar medium dramatically modifying its physical properties and chemical composition. Indirect evidence for the presence of such shocks has been reported from the especial chemistry detected toward a variety of astrophysical shocked environments. However, the internal physical structure of these shocks remains unresolved since their expected spatial scales are too small to be measured with current instrumentation. Here we report the first detection of a fully spatially resolved, MHD shock toward the infrared dark cloud (IRDC) G034.77-00.55. The shock, probed by silicon monoxide (SiO) and observed with the Atacama Large Millimeter/submillimeter Array (ALMA), is associated with the collision between the dense molecular gas of the cloud and a molecular gas flow pushed toward the IRDC by the nearby supernova remnant (SNR) W44. The interaction is occurring on subparsec spatial scales thanks to the enhanced magnetic field of the SNR, making the dissipation region of the MHD shock large enough to be resolved with ALMA. Our observations suggest that molecular flow–flow collisions can be triggered by stellar feedback, inducing shocked molecular gas densities compatible with those required for massive star formation

Deuterium fractionation across the infrared-dark cloud G034.77−00.55 interacting with the supernova remnant W44

Context. Supernova remnants (SNRs) may regulate star formation in galaxies. For example, SNR-driven shocks may form new molecular gas or compress pre-existing clouds and trigger the formation of new stars. / Aims. To test this scenario, we measured the deuteration of N2H+, DfracN2H+ – a well-studied tracer of pre-stellar cores – across the infrared-dark cloud (IRDC) G034.77-00.55, which is known to be experiencing a shock interaction with the SNR W44. / Methods. We use N2H+ and N2D+J = 1−0 single pointing observations obtained with the 30m antenna at the Instituto de Radioas-tronomia Millimetrica to infer DfracN2H+ towards five positions across the cloud, namely a massive core, different regions across the shock front, a dense clump, an+d ambient gas. / Results. We find DfracN2H+ in the range 0.03−0.1, which is several orders of magnitude larger than the cosmic D/H ratio (~10−5). The DfracN2H+ across the shock front is enhanced by more than a factor of 2 (DfracN2H+ ~ 0.05 - 0.07) with respect to the ambient gas (≤0.03) and simila+r to that measured generally in pre-stellar cores. Indeed, in the massive core and dense clump regions of this IRDC we measure DfracN2H+ ~ 0.01. / Conclusions. We find enhanced deuteration of N2H+ across the region of the shock, that is, at a level that is enhanced with respect to regions of unperturbed gas. It is possible that this has been induced by shock compression, which would then be indirect evidence that the shock is triggering conditions for future star formation. However, since unperturbed dense regions also show elevated levels of deuteration, further, higher-resolution studies are needed to better understand the structure and kinematics of the deuterated material in the shock region; for example, to decipher whether it is still in a relatively diffuse form or is already organised in a population of low-mass pre-stellar cores

15N Fractionation in Infrared-Dark Cloud Cores

Nitrogen is one of the most abundant elements in the Universe and its 14N/15N isotopic ratio has the potential to provide information about the initial environment in which our Sun formed. Recent findings suggest that the Solar System may have formed in a massive cluster since the presence of short-lived radioisotopes in meteorites can only be explained by the influence of a supernova. The aim of this project is to determine the 14N/15N ratio towards a sample of cold, massive dense cores at the initial stages in their evolution. We have observed the J=1-0 transitions of HCN, H13CN, HC15N, HN13C and H15NC toward a sample of 22 cores in 4 Infrared-Dark Clouds (IRDCs). IRDCs are believed to be the precursors of high-mass stars and star clusters. Assuming LTE and a temperature of 15K, the column densities of HCN, H13CN, HC15N, HN13C and H15NC are calculated and their 14N/15N ratio is determined for each core. The 14N/15N ratio measured in our sample of IRDC cores range between ~70 and >763 in HCN and between ~161 and ~541 in HNC. They are consistent with the terrestrial atmosphere (TA) and protosolar nebula (PSN) values, and with the ratios measured in low-mass pre-stellar cores. However, the 14N/15N ratios measured in cores C1, C3, F1, F2 and G2 do not agree with the results from similar studies toward the same massive cores using nitrogen bearing molecules with nitrile functional group (-CN) and nitrogen hydrides (-NH) although the ratio spread covers a similar range. Amongst the 4 IRDCs we measured relatively low 14N/15N ratios towards IRDC G which are comparable to those measured in small cosmomaterials and protoplanetary disks. The low average gas density of this cloud suggests that the gas density, rather than the gas temperature, may be the dominant parameter influencing the initial nitrogen isotopic composition in young PSN

The role of metacognition in self-critical rumination: an investigation in individuals presenting with low self-esteem

Background: No research, to date, has directly investigated the role of metacognition in self-critical rumination and low self-esteem. Aim: To investigate the presence of metacognitive beliefs about self-critical rumination; the goal of self-critical rumination and its stop signal; and the degree of detachment from intrusive self-critical thoughts. Method: Ten individuals reporting both a self-acknowledged tendency to judge themselves critically and having low self-esteem were assessed using metacognitive profiling, a semi-structured interview. Results: All participants endorsed both positive and negative metacognitive beliefs about self-critical rumination. Positive metacognitive beliefs concerned the usefulness of self-critical rumination as a means of improving cognitive performance and enhancing motivation. Negative metacognitive beliefs concerned the uncontrollability of self-critical rumination and its negative impact on mood, motivation and perception of self-worth. The primary goal of engaging in self-critical rumination was to achieve a better or clearer understanding of a given trigger situation or to feel more motivated to resolve it. However, only four participants were able to identify when this goal had been achieved, which was if the trigger situation were not to occur again. Participants unanimously stated that they were either unable to detach from their self-critical thoughts or could do so some of the time with varying degrees of success. More often than not, though, self-critical thoughts were viewed as facts, would rarely be seen as distorted or biased, and could take hours or days to dissipate. Conclusions: These findings provide preliminary evidence that specific facets of metacognition play a role in the escalation and perseveration of self-critical rumination

Deuterium fractionation across the infrared-dark cloud G034.77-00.55 interacting with the supernova remnant W44

Supernova remnants (SNRs) may regulate star formation in galaxies. For example, SNR-driven shocks may form new molecular gas or compress pre-existing clouds and trigger the formation of new stars. Aims. To test this scenario, we measured the deuteration of N2H+, DNfrac 2H+- a well-studied tracer of pre-stellar cores - across the infrared-dark cloud (IRDC) G034.77-00.55, which is known to be experiencing a shock interaction with the SNR W44. Methods. We use N2H+ and N2D+ J = 1-0 single pointing observations obtained with the 30m antenna at the Instituto de Radioastronomia Millimetrica to infer DN2H+ frac towards five positions across the cloud, namely a massive core, different regions across the shock front, a dense clump, and ambient gas. Results. We find DN2H+ frac in the range 0.03-0.1, which is several orders of magnitude larger than the cosmic D/H ratio (∼10-5). The DN2H+ frac across the shock front is enhanced by more than a factor of 2 (DNfrac 2H+∼ 0.05-0.07) with respect to the ambient gas (=0.03) and similar to that measured generally in pre-stellar cores. Indeed, in the massive core and dense clump regions of this IRDC we measure DN2H+ frac ∼ 0.1

Polarized Light from Massive Protoclusters (POLIMAP). I. Dissecting the Role of Magnetic Fields in the Massive Infrared Dark Cloud G28.37+0.07

Magnetic fields may play a crucial role in setting the initial conditions of massive star and star cluster formation. To investigate this, we report SOFIA-HAWC+ 214 μm observations of polarized thermal dust emission and high-resolution GBT-Argus C18O(1-0) observations toward the massive Infrared Dark Cloud (IRDC) G28.37+0.07. Considering the local dispersion of B-field orientations, we produce a map of the B-field strength of the IRDC, which exhibits values between ∼0.03 and 1 mG based on a refined Davis-Chandrasekhar-Fermi method proposed by Skalidis & Tassis. Comparing to a map of inferred density, the IRDC exhibits a B-n relation with a power-law index of 0.51 ± 0.02, which is consistent with a scenario of magnetically regulated anisotropic collapse. Consideration of the mass-to-flux ratio map indicates that magnetic fields are dynamically important in most regions of the IRDC. A virial analysis of a sample of massive, dense cores in the IRDC, including evaluation of magnetic and kinetic internal and surface terms, indicates consistency with virial equilibrium, sub-Alfvénic conditions, and a dominant role for B-fields in regulating collapse. A clear alignment of magnetic field morphology with the direction of the steepest column density gradient is also detected. However, there is no preferred orientation of protostellar outflow directions with the B-field. Overall, these results indicate that magnetic fields play a crucial role in regulating massive star and star cluster formation, and therefore they need to be accounted for in theoretical models of these processes

Relationship between cardiac deformation parameters measured by cardiovascular magnetic resonance and aerobic fitness in endurance athletes

Background: Athletic training leads to remodelling of both left and right ventricles with increased myocardial mass and cavity dilatation. Whether changes in cardiac strain parameters occur in response to training is less well established. In this study we investigated the relationship in trained athletes between cardiovascular magnetic resonance (CMR) derived strain parameters of cardiac function and fitness. Methods: 35 endurance athletes and 35 age and sex matched controls underwent CMR at 3.0T including cine imaging in multiple planes and tissue tagging by spatial modulation of magnetization (SPAMM). CMR data were analysed quantitatively reporting circumferential strain and torsion from tagged images and left and right ventricular longitudinal strain from feature tracking of cine images. Athletes performed a maximal ramp-incremental exercise test to determine the lactate threshold (LT) and maximal oxygen uptake (V̇O2max). Results: LV circumferential strain at all levels, LV twist and torsion, LV late diastolic longitudinal strain rate, RV peak longitudinal strain and RV early and late diastolic longitudinal strain rate were all lower in athletes than controls. On multivariable linear regression only LV torsion (beta=-0.37, P=0.03) had a significant association with LT. Only RV longitudinal late diastolic strain rate (beta=-0.35, P=0.03) had a significant association with V̇O2max. Conclusions: This cohort of endurance athletes had lower LV circumferential strain, LV torsion and biventricular diastolic strain rates than controls. Increased LT, which is a major determinant of performance in endurance athletes, was associated with decreased LV torsion. Further work is needed to understand the mechanisms by which this occurs