THROES: a caTalogue of HeRschel Observations of Evolved Stars. I. PACS range spectroscopy

This is the first of a series of papers presenting the THROES (A caTalogue of HeRschel Observations of Evolved Stars) project, intended to provide a comprehensive overview of the spectroscopic results obtained in the far-infrared (55-670 microns) with the Her- schel space observatory on low-to-intermediate mass evolved stars in our Galaxy. Here we introduce the catalogue of interactively reprocessed PACS (Photoconductor Array Camera and Spectrometer) spectra covering the 55-200 microns range for 114 stars in this category for which PACS range spectroscopic data is available in the Herschel Science Archive (HSA). Our sample includes objects spanning a range of evolutionary stages, from the asymptotic giant branch to the planetary nebula phase, displaying a wide variety of chemical and physical properties. The THROES/PACS catalogue is accessible via a dedicated web-based inter- face (https://throes.cab.inta-csic.es/) and includes not only the science-ready Herschel spectroscopic data for each source, but also complementary photometric and spectroscopic data from other infrared observatories, namely IRAS (Infrared Astronomical Satellite), ISO (Infrared Space Observatory) or AKARI, at overlapping wavelengths. Our goal is to create a legacy-value Herschel dataset that can be used by the scientific community in the future to deepen our knowledge and understanding of these latest stages of the evolution of low-to-intermediate mass stars.Comment: 38 page

Evidence for intermediate-age stellar populations in early-type galaxies from K-band spectroscopy

The study of stellar populations in early-type galaxies in different environments is a powerful tool for constraining their star formation histories. This study has been traditionally restricted to the optical range, where dwarfs around the turn-off and stars at the base of the RGB dominate the integrated light at all ages. The near-infrared spectral range is especially interesting since in the presence of an intermediate-age population, AGB stars are the main contributors. In this letter, we measure the near-infrared indices NaI and D$_{\rm CO}$ for a sample of 12 early-type galaxies in low density environments and compare them with the Fornax galaxy sample presented by Silva et al. (2008). The analysis of these indices in combination with Lick/IDS indices in the optical range reveals i) the NaI index is a metallicity indicator as good as C4668 in the optical range, and ii) D$_{\rm CO}$ is a tracer of intermediate-age stellar populations. We find that low-mass galaxies in low density environments show higher NaI and D$_{\rm CO}$ than those located in Fornax cluster, which points towards a late stage of star formation for the galaxies in less dense environments, in agreement with results from other studies using independent methods.Comment: 7 pages, 3 figures, accepted for publication in ApJ

Participation and Influence of the libero in recepcion and defence, in volleyball U-19

El objetivo fue conocer la participación e influencia líbero en fase de ataque y defensa, en etapas de formación. La muestra fueron 6948 acciones de juego, realizadas por los jugadores de los 21 equipos del Campeonato de España Juvenil masculino. Las variables fueron: función del receptor/defensor, zona de recepción/defensa en profundidad y lateralidad, eficacia de recepción/defensa, zona donde se realiza colocación en recepción/defensa, zona hacia donde se realiza la colocación en recepción/defensa, tiempo de ataque/contraataque y eficacia de ataque/contraataque. En recepción, existió asociación significativa entre función del receptor y zona de recepción en profundidad-lateralidad, y zona donde se realiza la colocación. En defensa, existió asociación significativa entre función del defensor y zona de defensa en profundidad-lateralidad, eficacia de defensa, zona donde se realiza la colocación, zona hacia donde se realiza la colocación y tiempo de contraataque. La influencia del líbero, en estas etapas, se manifiesta más en defensa que en recepciónThe aim was to know the participation and influence of the libero in side-out phase and counter-attack, in young athletes. The sample was 6948 game actions, carried out by the players of the 21 teams that participate in the Under-19 Spanish Championship. The variables were: player that intervened in reception/dig, depth and laterality reception/dig zone, reception/dig efficacy, setting zone in reception/dig, set´s area in reception/dig, tempo of attack/counterattack and attack/counterattack efficacy. In reception, showed significant association between player that intervened in reception, depth-laterality reception zone and the setting zone. In defense, showed significant association between the player that intervened in dig and the depth-laterality dig zone, dig efficacy, setting zone, set´s area and tempo of counterattack. The influence of the participation of the libero, in young athletes, appeared more often in defense than in the receptio

The colored Hanbury Brown--Twiss effect

The Hanbury Brown--Twiss effect is one of the celebrated phenomenologies of modern physics that accommodates equally well classical (interferences of waves) and quantum (correlations between indistinguishable particles) interpretations. The effect was discovered in the late thirties with a basic observation of Hanbury Brown that radio-pulses from two distinct antennas generate signals on the oscilloscope that wiggle similarly to the naked eye. When Hanbury Brown and his mathematician colleague Twiss took the obvious step to propose bringing the effect in the optical range, they met with considerable opposition as single-photon interferences were deemed impossible. The Hanbury Brown--Twiss effect is nowadays universally accepted and, being so fundamental, embodies many subtleties of our understanding of the wave/particle dual nature of light. Thanks to a novel experimental technique, we report here a generalized version of the Hanbury Brown--Twiss effect to include the frequency of the detected light, or, from the particle point of view, the energy of the detected photons. In addition to the known tendencies of indistinguishable photons to arrive together on the detector, we find that photons of different colors present the opposite characteristic of avoiding each others. We postulate that fermions can be similarly brought to exhibit positive (boson-like) correlations by frequency filtering.Comment: 18 pages, includes supplementary material of the derivation

Warm CO in evolved stars from the THROES catalogue. II. Herschel/PACS spectroscopy of C-rich envelopes

This is the second paper of a series making use of Herschel/PACS spectroscopy of evolved stars in the THROES catalogue to study the inner regions of their circumstellar envelopes (CSEs). We analyze the CO emission spectra, including a large number of high-$J$ CO lines (from $J$=14-13 to $J$=45-44), as a proxy for the warm molecular gas in the CSEs of a sample of bright carbon-rich stars spanning different evolutionary stages from the Asymptotic Giant Branch (AGB) to the young planetary nebulae (PNe) phase. We use the rotational diagram (RD) to derive rotational temperatures ($T_{\rm rot}$) and masses ($M_{\rm H_2}$) of the envelope layers where the CO transitions arise. We also obtain a first order estimate of the mass-loss rates and assess the impact of the opacity correction for a range of characteristic envelope radii. We use multi-epoch spectra for the well studied C-rich envelope IRC+10216 to investigate the impact of CO flux variability on the values of $T_{\rm rot}$ and $M_{\rm H_2}$. PACS sensitivity allowed the study of higher rotational numbers than before, indicating the presence of a significant amount of warmer gas ($\sim$200-900 K) not traceable with lower-$J$ CO observations at sub-mm/mm wavelengths. The masses are in the range $\sim10^{-2}-10^{-5}\,\rm M_{\odot}$, anti-correlated with temperature. For some strong CO emitters we infer a double temperature (warm $T_{\rm rot}\sim$400 K and hot $T_{\rm rot}\sim$820 K) component. From the analysis of IRC+10216, we corroborate that the effect of line variability is perceptible on the $T_{\rm rot}$ of the hot component only, and certainly insignificant on $M_{\rm H_2}$ and, hence, the mass-loss rate. Therefore, the parameters derived from the RD are robust even when strong line flux variability occurs, with the major source of uncertainty in the estimate of the mass-loss rate being the size of the CO-emitting volume.Comment: accepted in A&

Dripping Faucet Dynamics Clarified by an Improved Mass-Spring Model

An improved mass-spring model for a dripping faucet is presented. The model is constructed based on the numerical results which we recently obtained from fluid dynamical calculations. Both the fluid dynamical calculations and the present mass-spring model exhibit a variety of complex behavior including transition to chaos in good agreement with experiments. Further, the mass-spring model reveals fundamental dynamics inherent in the dripping faucet system.Comment: 17 pages, 17 figure

Exposure to nanometric pollutants in primary schools: Environmental implications

School children are highly susceptible to chemicals in the atmosphere. Some studies have demonstrated that the pollution is related to respiratory problems and impaired cognitive development in children. In this context, the objective of this study was to determine nanoparticles and associated species and their origin in fresh air currents in La Salle Canoas School in Rio Grande do Sul (Brazil). Different analyses by using high-resolution transmission electron microscopy with energy-dispersive, X-ray spectroscopy (HR-TEM/SAED/EDS), and the scanning (STEM) mode were carried out. The EDS analysis of the atmospheric particles demonstrated that materials contain a significant proportion of elements such as Cr, Fe, Mn, Ni, and Si and other trace metals Zn, Pb, Zr, Ca, Cu, K, Cr, and Cd from exhaust and non-exhaust. The main source of the particles was emission from internal combustion in motor vehicles, road dust, and brake and tire wear. This emphasizes the importance of urban planning to reduce exposure of children to traffic gas emissions

The high schools in Colombia and the creation of a convenient environment for organizational change / As escolas secundárias na Colômbia e a criação de um ambiente conveniente para a mudança organizacional

Research on change management and its impact on organizational performance has become a significant factor for the preservation of organizations that operates in markets with high level of uncertainty.  However, change management cannot be considered as an attribute of the organizations by themselves; it is closely related to the management and leadership skills of the chancellor, principal or school directors. Being the high schools, those organizations that must be at the forefront of the training processes; this research aims to establish the perception of the schools’ directors regarding the creation of an environment conducive to organizational change. To do this, a research instrument was applied to 338 schools throughout the country, extracted from a ranking of the best high schools in Colombia, according to the results of the state tests that are performed on their graduates. The main results indicate the use of proactive language, transmit positive energy and demonstration of gratitude are the most frequent skills to lead positive change in Schools. Likewise, assertive communication becomes a skill to improve and develop change processes in those educational institutions

Size determination and quantification of engineered cerium oxide nanoparticles by flow field-flow fractionation coupled to inductively coupled plasma mass spectrometry

Facing the lack of studies on characterization and quantification of cerium oxide nanoparticles (CeO2 NPs), whose consumption and release is greatly increasing, this work proposes a method for their sizing and quantification by Flow Field-flow Fractionation (FFFF) coupled to Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Two modalities of FFFF (Asymmetric Flow- and Hollow Fiber-Flow Field Flow Fractionation, AF4 and HF5, respectively) are compared, and their advantages and limitations discussed. Experimental conditions (carrier composition, pH, ionic strength, crossflow and carrier flow rates) are studied in detail in terms of NP separation, recovery, and repeatability. Size characterization of CeO2 NPs was addressed by different approaches. In the absence of feasible size standards of CeO2 NPs, suspensions of Ag, Au, and SiO2 NPs of known size were investigated. Ag and Au NPs failed to show a comparable behavior to that of the CeO2 NPs, whereas the use of SiO2 NPs provided size estimations in agreement to those predicted by the theory. The latter approach was thus used for characterizing the size of CeO2 NPs in a commercial suspension. Results were in adequate concordance with those achieved by transmission electron microscopy, X-ray diffraction and dynamic light scattering. The quantification of CeO2 NPs in the commercial suspension by AF4-ICP-MS required the use of a CeO2 NPs standards, since the use of ionic cerium resulted in low recoveries (99 ± 9% vs. 73 ± 7%, respectively). A limit of detection of 0.9 µg L-1 CeO2 corresponding to a number concentration of 1.8 × 1012 L-1 for NPs of 5 nm was achieved for an injection volume of 100 µL