Bounds on the mass and abundance of dark compact objects and black holes in dwarf spheroidal galaxy halos

We establish new dynamical constraints on the mass and abundance of compact objects in the halo of dwarf spheroidal galaxies. In order to preserve kinematically cold the second peak of the Ursa Minor dwarf spheroidal (UMi dSph) against gravitational scattering, we place upper limits on the density of compact objects as a function of their assumed mass. The mass of the dark matter constituents cannot be larger than 1000 solar masses at a halo density in UMi's core of 0.35 solar masses/pc^3. This constraint rules out a scenario in which dark halo cores are formed by two-body relaxation processes. Our bounds on the fraction of dark matter in compact objects with masses >3000 solar masses improve those based on dynamical arguments in the Galactic halo. In particular, objects with masses $\sim 10^{5}$ solar masses can comprise no more than a halo mass fraction $\sim 0.01$. Better determinations of the velocity dispersion of old overdense regions in dSphs may result in more stringent constraints on the mass of halo objects. For illustration, if the preliminary value of 0.5 km/s for the secondary peak of UMi is confirmed, compact objects with masses above $\sim 100$ solar masses could be excluded from comprising all its dark matter halo.Comment: 6 pages, 2 figures, accepted for publication in ApJ Letter

Dark Matter Subhalos in the Ursa Minor Dwarf Galaxy

Through numerical simulations, we study the dissolution timescale of the Ursa Minor cold stellar clump, due to the combination of phase-mixing and gravitational encounters with compact dark substructures in the halo of Ursa Minor. We compare two scenarios; one where the dark halo is made up by a smooth mass distribution of light particles and one where the halo contains 10% of its mass in the form of substructures (subhalos). In a smooth halo, the stellar clump survives for a Hubble time provided that the dark matter halo has a big core. In contrast, when the point-mass dark substructures are added, the clump survives barely for \sim 1.5 Gyr. These results suggest a strong test to the \Lambda-cold dark matter scenario at dwarf galaxy scale.Comment: accepted for publication in Ap

The survival of dynamical fossils in dwarf spheroidal galaxies in conventional and modified dynamics

The survival of unbound density substructure against orbital mixing imposes strong constraints on the slope of the underlying gravitational potential and provides a new test on modified gravities. Here we investigate whether the interpretation that the stellar clump in Ursa Minor (UMi) dwarf spheroidal galaxy is a `dynamical fossil' is consistent with Modified Newtonian dynamics (MOND). For UMi mass models inferred by fitting the velocity dispersion profile, the stellar clump around the second peak of UMi is erased very rapidly, within 1.25 Gyr (6.5 orbits), even with the inclusion of self-gravity. We find that the clump can hardly survive for more than 2 Gyr even under more generous conditions. Alternative scenarios which could lead to a kinematically cold clump are discussed but, so far, none of them were found to be fully satisfactory. Our conclusion is that the cold clump in UMi poses a challenge for both LambdaCDM and MOND.Comment: 14 pages, 13 figures, accepted for publication in MNRA

Efectividad del consejo médico a pacientes alcohólicos y bebedores excesivos atendidos en consultas de atención primaria

ObjetivoComprobar la efectividad del consejo médico antialcohólico que se da en las consultas de atención primaria.DiseñoEstudio cuasi-experimental de tipo «antes-después», abierto, multicéntrico.EmplazamientoCatorce consultas médicas de atención primaria (7 rurales y 7 urbanas) de la provincia de Córdoba (España).ParticipantesUn total de 306 pacientes de ambos sexos, captados mediante búsqueda de casos, que presentaban un consumo de alcohol ≥ 35 (varones) y 21 (mujeres) U a la semana, y/o síndrome de dependencia alcohólica (SDA) (MALTS-O ≥ 11).IntervencionesA todos se les ofreció consejo médico breve antialcohólico y se les hizo un seguimiento para valoración de su estado a los 3 meses, 1 y 2 años.Mediciones principalesLa variable de respuesta fue la suma del consumo autorreferido, más valores normales de GGT, y la confirmación del familiar. El análisis del estudio fue por «intención de tratar».ResultadosDe los 306 pacientes incluidos, en un 95,1% de los casos se trataba de varones y un 78,4% presentaba SDA. Al cabo de 2 años, el 38,89% (IC del 95%, 32,2-44,3%) había alcanzado el objetivo terapéutico: un 23,85% se encontraba en abstinencia total y el 15,0% presentaba un consumo moderado de alcohol, por debajo del límite de riesgo. El comienzo del consumo excesivo antes de los 16 años (odds ratio [OR], 3,0885), vivir en un barrio marginal (OR, 3,2103), consumir tabaco (OR, 1,7187) y un test de CAGE positivo (OR, 1,9949) se asociaron al fracaso de la intervención (p < 0,05).ConclusionesSe demuestra la alta efectividad del consejo antialcohólico impartido por el médico de familia en condiciones habituales de consulta, tanto en bebedores excesivos como en aquellos con SDA.AimTo determine the effectiveness of medical counseling for alcohol abuse, when it is provided in primary care centers.DesignQuasi-experimental, open, multicenter before-after study.Setting14 primary care physician's practices (7 rural, 7 urban) in the province of Córdoba (Spain).Participants306 patients of both sexes, recruited with a case-finding strategy, who consumed ≥35 (men) or ≥21 (women) IU per week, or who had alcohol dependence syndrome (ADS) (MALTS score O≥11).InterventionsAll patients were offered brief counseling to reduce drinking, and all were followed to evaluate their status 3 months, 1 year and 2 years later.Main measuresThe response variable was selfreported alcohol consumption together with normal GGT values or confirmation of alcohol consumption by a relative. The results were subjected to intention-to-treat analysis.ResultsOf the 306 patients included in the study, 95.1% were men and 78.4% had ADS. After 2 years 38.89% (95% CI, 32.2%-44.3%) had attained their treatment goal: 23.85% were in complete abstinence, and 15.0% consumed moderate amounts of alcohol below the limit considered to indicate risk. Starting excessive consumption at less than 16 years of age (odds ratio [OR], 3.0885), living in a slum (OR, 3.2103), smoking (OR, 1.7187), and a positive CAGE test (OR, 1.9949) were associated with failure of the intervention (P<.05).ConclusionsCounseling provided by the family doctor was highly effective under the usual conditions of general practice, both for patients with excessive alcohol consumption and for patients with con ADS

Gram-negative prosthetic joint infection: outcome of a debridement, antibiotics and implant retention approach. A large multicentre study

AbstractWe aim to evaluate the epidemiology and outcome of gram-negative prosthetic joint infection (GN-PJI) treated with debridement, antibiotics and implant retention (DAIR), identify factors predictive of failure, and determine the impact of ciprofloxacin use on prognosis. We performed a retrospective, multicentre, observational study of GN-PJI diagnosed from 2003 through to 2010 in 16 Spanish hospitals. We define failure as persistence or reappearance of the inflammatory joint signs during follow-up, leading to unplanned surgery or repeat debridement >30 days from the index surgery related death, or suppressive antimicrobial therapy. Parameters predicting failure were analysed with a Cox regression model. A total of 242 patients (33% men; median age 76 years, interquartile range (IQR) 68–81) with 242 episodes of GN-PJI were studied. The implants included 150 (62%) hip, 85 (35%) knee, five (2%) shoulder and two (1%) elbow prostheses. There were 189 (78%) acute infections. Causative microorganisms were Enterobacteriaceae in 78%, Pseudomonas spp. in 20%, and other gram-negative bacilli in 2%. Overall, 19% of isolates were ciprofloxacin resistant. DAIR was used in 174 (72%) cases, with an overall success rate of 68%, which increased to 79% after a median of 25 months' follow-up in ciprofloxacin-susceptible GN-PJIs treated with ciprofloxacin. Ciprofloxacin treatment exhibited an independent protective effect (adjusted hazard ratio (aHR) 0.23; 95% CI, 0.13–0.40; p <0.001), whereas chronic renal impairment predicted failure (aHR, 2.56; 95% CI, 1.14–5.77; p 0.0232). Our results confirm a 79% success rate in ciprofloxacin-susceptible GN-PJI treated with debridement, ciprofloxacin and implant retention. New therapeutic strategies are needed for ciprofloxacin-resistant PJI

An upper limit on the mass of the black hole in Ursa Minor dwarf galaxy

The well-established correlations between the mass of massive black holes (BHs) in the nuclei of most studied galaxies and various global properties of their hosting galaxy lend support to the idea that dwarf galaxies and globular clusters could also host a BH in their centers. Direct kinematic detection of BHs in dwarf spheroidal (dSph) galaxies are seriously hindered by the small number of stars inside the gravitational influence region of the BH. The aim of this Letter is to establish an upper dynamical limit on the mass of the putative BH in the Ursa Minor (UMi) dSph galaxy. We present direct N-body simulations of the tidal disruption of the dynamical fossil observed in UMi, with and without a massive BH. We find that the observed substructure is incompatible with the presence of a massive BH of (2-3)x10^4 Msun within the core of UMi. These limits are consistent with the extrapolation of the M_{BH}-sigma relation to the M_{BH}<10^6 Msun regime. We also show that the BH may be off-center with respect to the center of symmetry of the whole galaxy.Comment: 6 pages, 3 figures, ApJL (in press

Surface textures of detrital pyroxenes in coastal dune sands (western Gulf of Mexico, Mexico): implications for their preservation and geoenvironmental processes

This work investigates how the surface textures and morphology of pyroxene grains evolve during their source‐to‐sink history. This study applies to detrital clinopyroxenes concentrated in coastal dune sands of the Gulf of Mexico which were sourced in the Trans Mexican Volcanic Belt then transported and deposited in environments subject to limited chemical weathering. The composition and morphology of the pyroxenes was characterised using single‐grain geochemical analysis and surface texture imagery with a novel approach based on the compactness property to assess the shape of minerals. This reveals heterogenous diopside‐augite populations, displaying mineral morphologies dominantly controlled by impact breakage along cleavages, little physical abrasion along their edges and with limited evidence for chemical weathering. Mechanical surface textures dominate over mechanical/chemical and chemical surface textures. These mechanical surface textures are preserved primarily as flat cleavage surfaces and rounded edges inherited from fluvial‐intertidal and aeolian transport, respectively. Mechanically/chemically induced surface textures are preserved as elongated depressions. Chemical surface textures are sparse and mostly represented by mammillated textures that suggest local dissolution under subaqueous conditions. The scarcity of chemical surface textures is attributed to frequent fragmentation of the clinopyroxenes along cleavages and limited chemical weathering during transport of the observed populations. Clinopyroxene grains in the coastal dune sands primarily retain surface characteristics from fluvial transport. Although the breakage of minerals along cleavages can obscure their original morphology under a weathering‐limited erosion regime, this study shows how surface textures and morphology of pyroxene grains is used to determine episodes of transport and deposition close to volcanic environments. The use of the compactness property as a shape descriptor measurement of particles provides an alternative approach to observe how clinopyroxene remains unaltered despite the high energy conditions of the coastal area

Characterization and Decomposition of the Natural van der Waals SnSb2Te4 under Compression

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.inorgchem.0c01086.[EN] High pressure X-ray diffraction, Raman scattering, and electrical measurements, together with theoretical calculations, which include the analysis of the topological electron density and electronic localization function, evidence the presence of an isostructural phase transition around 2 GPa, a Fermi resonance around 3.5 GPa, and a pressure-induced decomposition of SnSb2Te4 into the high-pressure phases of its parent binary compounds (alpha-Sb2Te3 and SnTe) above 7 GPa. The internal polyhedral compressibility, the behavior of the Raman-active modes, the electrical behavior, and the nature of its different bonds under compression have been discussed and compared with their parent binary compounds and with related ternary materials. In this context, the Raman spectrum of SnSb2Te4 exhibits vibrational modes that are associated but forbidden in rocksalt-type SnTe; thus showing a novel way to experimentally observe the forbidden vibrational modes of some compounds. Here, some of the bonds are identified with metavalent bonding, which were already observed in their parent binary compounds. The behavior of SnSb2Te4 is framed within the extended orbital radii map of BA(2)Te(4) compounds, so our results pave the way to understand the pressure behavior and stability ranges of other "natural van der Waals" compounds with similar stoichiometry.This work has been performed under financial support from the Spanish MINECO under Project MALTA-CONSOLIDER TEAM network (RED2018-102612-T) and Project FIS2017-83295-P, from Generalitat Valenciana under Project PROMETEO/2018/123. This publication is a product of the "Programa de Valoracion y Recursos Conjuntos de I+D+i VLC/CAMPUS and has been financed by the Spanish Ministerio de Educacion, Cultura y Deporte, as part of "Programa Campus de Excelencia Internacional". Supercomputer time has been provided by the Red Espanola de Supercomputacion (RES) and the MALTA cluster. J.A.S. acknowledges a "Ramon y Cajal" fellowship (RYC-2015-17482) for financial support, and E.L.D.S. acknowledges Marie Sklodowska-Curie Grant No. 785789-COMEX from the European Union's Horizon 2020 research and innovation program. We also thank ALBA synchrotron and DIAMOND light source for funded experiments.Sans-Tresserras, JÁ.; Vilaplana Cerda, RI.; Da Silva, EL.; Popescu, C.; Cuenca-Gotor, VP.; Andrada-Chacón, A.; Sánchez-Benitez, J.... (2020). Characterization and Decomposition of the Natural van der Waals SnSb2Te4 under Compression. Inorganic Chemistry. 59(14):9900-9918. https://doi.org/10.1021/acs.inorgchem.0c01086S990099185914Mellnik, A. R., Lee, J. S., Richardella, A., Grab, J. L., Mintun, P. J., Fischer, M. H., … Ralph, D. C. (2014). Spin-transfer torque generated by a topological insulator. Nature, 511(7510), 449-451. doi:10.1038/nature13534Chen, Y. L., Analytis, J. G., Chu, J.-H., Liu, Z. K., Mo, S.-K., Qi, X. L., … Shen, Z.-X. (2009). 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Activation of Ventral Tegmental Area 5-HT2C Receptors Reduces Incentive Motivation

FUNDING AND DISCLOSURE The research was funded by Wellcome Trust (WT098012) to LKH; and National Institute of Health (DK056731) and the Marilyn H. Vincent Foundation to MGM. The University of Michigan Transgenic Core facility is partially supported by the NIH-funded University of Michigan Center for Gastrointestinal Research (DK034933). The remaining authors declare no conflict of interest. ACKNOWLEDGMENTS We thank Dr Celine Cansell, Ms Raffaella Chianese and the staff of the Medical Research Facility for technical assistance. We thank Dr Vladimir Orduña for the scientific advice and technical assistance.Peer reviewedPublisher PD