The emergence of classical behavior in magnetic adatoms

A wide class of nanomagnets shows striking quantum behavior, known as quantum spin tunneling (QST): instead of two degenerate ground states with opposite magnetizations, a bonding-antibonding pair forms, resulting in a splitting of the ground state doublet with wave functions linear combination of two classically opposite magnetic states, leading to the quenching of their magnetic moment. Here we study how QST is destroyed and classical behavior emerges in the case of magnetic adatoms, as the strength of their coupling, either to the substrate or to each other, is increased. Both spin-substrate and spin-spin coupling renormalize the QST splitting to zero allowing the environmental decoherence to eliminate superpositions between classical states, leading to the emergence of spontaneous magnetization.Comment: 5 pages, 4 figure

Morphological and geochemical features of crater lakes in Costa Rica: an overview.

This paper describes the compositional and morphological features of the crater lakes found in the volcanoes of Rincón de La Vieja, Poás, Irazú, Congo and Tenorio volcanoes (Costa Rica). As evidenced by the distribution of the water and dissolved gas chemistry along vertical profiles, the different fluid sources feeding the lakes reflect the present status of each of the volcanic systems. The chemical features of the Caliente (Poás volcano) and Rincón crater (Rincón de la Vieja volcano) lakes are mainly dependent on i) inputs of magmatic fluids from sub-lacustrine fumaroles and ii) water-rock interaction processes. Conversely, the Irazú lake is mainly affected by the presence of CO2(H2S)-rich fluids discharged from a hydrothermal system, which masked possible magmatic fluid contributions. Rainfall and organic activity are the main factors responsible for the chemical composition of Hule, Botos, Congo and Tenorio lakes. The chemical and isotopic water composition of Botos, Irazú and Hule lakes have displayed no significant variations along the vertical profiles. In contrast, Caliente lake shows a distinctive chemical stratification, mainly involving F-, Cl- and SO4 2-. The behaviour of these compounds seems to be governed by both dissolution of highly acidic species, i.e. HF, HCl and SO2 released from the magmatic environment, and microbial activity. Despite the significant increases with depth of dissolved CO2 at Caliente and Irazú lakes, the hazard for Nyos-type gas eruptions can be considered negligible, since i) the water volumes are too small and ii) the convective heat transfer limits the CO2 recharge rate. The relatively high concentrations of dissolved CO2 measured at the maximum depth of the Hule lake are likely produced by both degradation of organic material and degassing from a deep source. The sporadic episodes of fish deaths recently observed in this lake can be associated with lake overturn processes that have favoured the rise up to the lake surface of deep, oxygen-depleted waters.Journal of limnolog

RIP2 plays a role in cardiac Ca2+ mishandling prompted by chronic kidney disease

post-print81,7 K

ONGOING RESEARCH ON SPECIES OF DINOPHYSIS: ALTERNATIVES WITH UNCULTURABLE DINOFLAGELLATES

Dinophysis 200

Influence of Chemical Enhancers and Iontophoresis on the In Vitro Transdermal Permeation of Propranolol: Evaluation by Dermatopharmacokinetics

[EN] The aims of this study were to assess, in vitro, the possibility of administering propranolol transdermally and to evaluate the usefulness of the dermatopharmacokinetic (DPK) method in assessing the transport of drugs through stratum corneum, using propranolol as a model compound. Four chemical enhancers (decenoic and oleic acid, laurocapram, and R-(+)-limonene) and iontophoresis at two current densities, 0.25 and 0.5 mA/cm(2) were tested. R-(+)-limonene, and iontophoresis at 0.5 mA/cm(2) were proven to be the most efficient in increasing propranolol transdermal flux, both doubled the original propranolol transdermal flux. Iontophoresis was demonstrated to be superior than the chemical enhancer because it allowed faster delivery of the drug. The DPK method was sufficiently sensitive to detect subtle vehicle-induced effects on the skin permeation of propranolol. The shorter duration of these experiments and their ability to provide mechanistic information about partition between vehicle and skin and diffusivity through skin place them as practical and potentially insightful approach to quantify and, ultimately, optimize topical bioavailability.This research was funded by Ministerio de Ciencia e Innovación (AP2007-03456) and the Universidad CEU Cardenal Herrera.Calatayud-Pascual, M.; Sebastian-Morelló, M.; Balaguer-Fernandez, C.; Delgado-Charro, M.; Lopez-Castellano, A.; Merino Sanjuán, V. (2018). Influence of Chemical Enhancers and Iontophoresis on the In Vitro Transdermal Permeation of Propranolol: Evaluation by Dermatopharmacokinetics. Pharmaceutics. 10(4):1-15. https://doi.org/10.3390/pharmaceutics10040265S11510

Resolving galaxies in time and space: II: Uncertainties in the spectral synthesis of datacubes

In a companion paper we have presented many products derived from the application of the spectral synthesis code STARLIGHT to datacubes from the CALIFA survey, including 2D maps of stellar population properties and 1D averages in the temporal and spatial dimensions. Here we evaluate the uncertainties in these products. Uncertainties due to noise and spectral shape calibration errors and to the synthesis method are investigated by means of a suite of simulations based on 1638 CALIFA spectra for NGC 2916, with perturbations amplitudes gauged in terms of the expected errors. A separate study was conducted to assess uncertainties related to the choice of evolutionary synthesis models. We compare results obtained with the Bruzual & Charlot models, a preliminary update of them, and a combination of spectra derived from the Granada and MILES models. About 100k CALIFA spectra are used in this comparison. Noise and shape-related errors at the level expected for CALIFA propagate to 0.10-0.15 dex uncertainties in stellar masses, mean ages and metallicities. Uncertainties in A_V increase from 0.06 mag in the case of random noise to 0.16 mag for shape errors. Higher order products such as SFHs are more uncertain, but still relatively stable. Due to the large number statistics of datacubes, spatial averaging reduces uncertainties while preserving information on the history and structure of stellar populations. Radial profiles of global properties, as well as SFHs averaged over different regions are much more stable than for individual spaxels. Uncertainties related to the choice of base models are larger than those associated with data and method. Differences in mean age, mass and metallicity are ~ 0.15 to 0.25 dex, and 0.1 mag in A_V. Spectral residuals are ~ 1% on average, but with systematic features of up to 4%. The origin of these features is discussed. (Abridged)Comment: A&A, accepte

A Hubble Space Telescope ACS Search for Brown Dwarf Binaries in the Pleiades Open Cluster

We present the results of a high-resolution imaging survey for brown dwarf binaries in the Pleiades open cluster. The observations were carried out with the Advance Camera for Surveys onboard the Hubble Space Telescope. Our sample consists of 15 bona-fide brown dwarfs. We confirm 2 binaries and detect their orbital motion, but we did not resolve any new binary candidates in the separation range between 5.4AU and 1700AU and masses in the range 0.035--0.065~Msun. Together with the results of our previous study (Martin et al., 2003), we can derive a visual binary frequency of 13.3$^{+13.7}_{-4.3}$\% for separations greater than 7~AU masses between 0.055--0.065~M_{\sun} and mass ratios between 0.45--0.9$<q<$1.0. The other observed properties of Pleiades brown dwarf binaries (distributions of separation and mass ratio) appear to be similar to their older counterparts in the field.Comment: 29 pages, 7 figures, 6 tables, accepted for publication in Ap

Detecting the footprint of selection on the genomes of Murciano-Granadina goats

Artificial selection is one of the major forces modifying the genetic composition of livestock populations. Identifying genes under selection could be useful to elucidate their impact on phenotypic variation. We aimed to identify genomic regions targeted by selection for dairy and pigmentation traits in Murciano-Granadina goats. Performance of a selection scan based on the integrated haplotype score test in a population of 1183 Murciano-Granadina goats resulted in the identification of 77 candidate genomic regions/SNPs. The most significant selective sweeps mapped to chromosomes 1 (69.86&nbsp;Mb), 4 (41.80–49.95&nbsp;Mb), 11 (65.74&nbsp;Mb), 12 (31.24 and 52.51&nbsp;Mb), 17 (34.76–37.67&nbsp;Mb), 22 (31.75&nbsp;Mb), and 26 (26.69–31.05&nbsp;Mb). By using previously generated RNA-Seq data, we built a catalogue of 6414 genes that are differentially expressed across goat lactation (i.e. 78&nbsp;days post-partum, early lactation; 216&nbsp;days post-partum, late lactation; 285&nbsp;days post-partum, dry period). Interestingly, 183 of these genes mapped to selective sweeps and several of them display functions related with lipid, protein, and carbohydrate metabolism, insulin signaling, cell proliferation, as well as mammary development and involution. Of particular interest are the CSN3 and CSN1S2 genes, which encode two major milk proteins. Additionally, we found three pigmentation genes (GLI3, MC1R, and MITF) co-localizing with selective sweeps. Performance of a genome-wide association study and Sanger sequencing and TaqMan genotyping experiments revealed that the c.801C&gt;G (p.Cys267Trp) polymorphism in the melanocortin 1 receptor (MC1R) gene is the main determinant of the black (GG or GC genotypes) and brown (CC genotypes) colorations of Murciano-Granadina goats