Lithium in the Hyades L5 brown dwarf 2MASS J04183483+2131275

Aims. From the luminosity, effective temperature and age of the Hyades brown dwarf 2MASS J04183483+2131275 (2M0418), substellar evolutionary models predict a mass in the range 39−55 Jupiter masses (MJup) which is insufficient to produce any substantial lithium burning except for the very upper range >53 MJup. Our goal is to measure the abundance of lithium in this object, test the consistency between models and observations and refine constraints on the mass and age of the object. Methods. We used the 10.4-m Gran Telescopio Canarias (GTC) with its low-dispersion optical spectrograph to obtain ten spectra of 2277 s each covering the range 6300–10 300 Å with a resolving power of R ~ 500. Results. In the individual spectra, which span several months, we detect persistent unresolved Hα in emission with pseudo equivalent widths (pEW) in the range 45–150 Å and absorption lines of various alkalis with the typical strengths found in objects of L5 spectral type. The lithium resonance line at 6707.8 Å is detected with pEW of 18 ± 4 Å in 2M0418 (L5). Conclusions. We determine a lithium abundance of log N(Li) = 3.0 ± 0.4 dex consistent with a minimum preservation of 90% of this element which confirms 2M0418 as a brown dwarf with a maximum mass of 52 MJup. We infer a maximum age for the Hyades of 775 Myr from a comparison with the BHAC15 models. Combining recent results from the literature with our study, we constrain the mass of 2M0418 to 45–52 MJup and the age of the cluster to 580–775 Myr (1σ) based on the lithium depletion boundary method.We thank the referee for a detailed report that improved the quality of this manuscript. This research has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under the grants AYA2015- 69350-C3-2-P and AYA2015-69350-C3-3-P. We thank Yakiv Pavlenko for his calculations of equivalent widths at different temperatures, Isabelle Baraffe for her models, and Eduardo Martín for sharing his results prior to publication. This work is based on observations made with the Gran Telescopio Canarias (GTC), operated on the island of La Palma in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias (programme GTC77- 16B led by Pérez Garrido). This research has made use of the Simbad and Vizier databases, operated at the Centre de Données Astronomiques de Strasbourg (CDS), and of NASA’s Astrophysics Data System Bibliographic Services (ADS). We thank John Stauffer for kindly providing the optical spectra of the K and M Hyades members published in 1997 (Stauffer et al. 1997a)

Clasificador de subgéneros de música electrónica

¿Qué hace que nosotros, los humanos, seamos capaces de diferenciar canciones de distintos géneros? Quizás el lector se habrá encontrado alguna vez en la difícil situación de explicar a alguien “cómo suena” el estilo de música que le gusta. Entonces, ¿podría existir una clasificación de géneros automática?. El incremento del contenido digital disponible en diversas áreas nos obliga a buscar formas más rápidas y eficientes de almacenar y ordenar la información. Nunca había sido tan fácil hacer música y miles de canciones nuevas se publican cada día. En sitios web como Beatport, cada semana se publican 25.000 canciones nuevas de música electrónica. Probablemente sería de gran ayuda clasificar automáticamente todo este contenido. En la actualidad, con los algoritmos de aprendizaje automático se buscan patrones comunes para clasificar y facilitar el acceso de datos digitalizados. Durante los últimos 20 años, se ha estudiado el reconocimiento de géneros musicales para predecir automáticamente el género de una canción. En los estudios pasados se han clasificado géneros y subgéneros en distintos estilos musicales, pero hasta donde alcanza nuestro conocimiento, nunca se ha abordado la clasificación de subgéneros de música electrónica. No obstante, existe una amplia variedad de música electrónica y a pesar de que para un oyente ocasional todo podría sonar tremendamente parecido, los fans distinguen entre subgéneros. Por lo tanto tienen que tener características que los definan. La clasificación en géneros es subjetiva, pero partiendo de un conjunto debidamente clasificado podemos pensar que los diferentes géneros tienen algunas cualidades intrínsecas objetivables que los caracterizan. En este proyecto, nuestro objetivo es clasificar automáticamente subgéneros de música electrónica atendiendo exclusivamente a datos de audio

A financial analysis of born-global firms: evidence from Spain

From the beginning of the 1970s to the present day, significant changes have taken place in the competitive and organizational behavior of small and medium-sized companies (SMEs). Recently, some of these factors have applied more intensively, and this has given rise to growth in the number of new companies that undertake overseas operations almost immediately (known as born globals). The phenomenon of early internationalization is relatively recent, so there are still many aspects that need to be studied. The objective of this study is to contribute to the scarce empirical literature existing in Spain on this topic, by providing evidence on the possible differences in character of the born-global firms compared with the rest of exporting companies. To this end, the focus of the study is on the analysis of variables such as the size and sector of activity of these companies, and their principal economic and financial magnitudes. A sample of 1,324 Spanish SMEs that were exporting in 2007 was surveyed; of this total approximately 12% identified themselves as having adopted early internationalization. The results obtained indicate that the born-global firms are, on average, smaller; they are classified mostly to the services sector; and they are much more leveraged than the rest of Spanish SMEs that export

Estudio preliminar de las orquídeas de la Isla de Ometepe

En la Isla de Ometepe se identificaron 18 taxones de orquídeas (Orchydiaceae) so- bre tres sustratos y biotopos diferentes: terrestres, litófitas y epífitas. La mayor riqueza parece concentrarse en el volcán Concepción, probablemente debido a su menor cobertura vegetal y la continua expulsión de cenizas vol- cánicas, gases tóxicos, y ráfagas de viento ex- tremo. El presente trabajo es un catálogo pre- liminar de la flora de orquídeas de la Isla de Ometepe, que deberá enriquecerse en el futuro según se acometan nuevas campañas de pros- pección florística. En particular, resulta intere- sante señalar que los diferentes ecosistemas al- bergados en los dos volcanes de la isla habrán de implicar necesariamente espectros florísti- cos distintos, lo que reviste de mayor interés al estudio de las orquídeas de Ometepe. El volcán Maderas, con mayor cobertura forestal, tiene una flora en orquídeas diferente del Concep- ción. A parte de éstas, el presente trabajo do- cumenta otras especies vegetales interesantes por su restringida distribución en Nicaragua, en general, y en Ometepe en particular; caso de Gunera sp, Pernettya sp y Utricularia endresii, esta última una planta carnívora. Todas fueron recogidas en el volcán Concepción, salvo la úl- tima que lo fue en ambos.Peer Reviewe

Hernia discal lumbar: Tratamiento conservador

Existe una gran demanda de patología lumbar crónica y aguda que debe de tratarse conjuntamente entre el especialista en Rehabilitación y el Cirujano de columna vertebral. En este trabajo se detallan las posibilidades del tratamiento conservador antes de optar por la cirugía. Se realiza una revisión bibliográfica de los resultados conservadores del tratamiento de la lumbociática de origen discal comparando aquellos estudios publicados con validez estadística. Se detallan las modernas pautas de rehabilitación y los resultados según los autores de los diversos tipos de tratamiento. El resumen es que muchas lumbociáticas están mal tratadas de forma conservadora con lo que aumenta el número de intervenciones quirúrgicas, se necesita pues un abordaje interdisciplinar para el tratamiento de estos enfermos.There are many cases of acute and chronic lumbar pathology demanding a combined treatment protocol in which both the physiotherapist and the spine surgeon can take part. In this work the possibilities for conservative treatment before a final surgical option are described. Based on a review of the literature, the results after conservative treatment of lumbosciatica with statistical value are discussed. Modern rehabilitation techniques and their results are exposed. As conclusion, most patients with lumbosciatica are treated with poor conservative protocols, and therefore the number of spinal surgeries increases because unsatisfactory results. An interdisciplinary approach seems to be desirable for treatment of these patients

Influence of the notch-sharpening technique on styrene-acrylonitrile fracture behavior

The Centre Catala del Plastic and Universidad Rey Juan Carlos laboratories joined forces to investigate the effect of the notch-sharpening technique on the fracture parameters of styrene-acrylonitrile. Contact notch-sharpening techniques, such as razor tapping, razor sliding, and razor broaching, and a noncontact procedure, femtolaser, were analyzed. The fracture values of the samples with notches sharpened via contact techniques were divided into two groups: one with pop-in and the other with no pop-in in the load-displacement records; this resulted in the lowest and highest fracture toughnesses, respectively. The fracture parameters of the specimens with notches sharpened via a femtolaser were between those of the samples with notches sharpened via contact procedures in which pop-in occurred and those in which it did not. To explain these results, the crack front of the nontested specimens after sharpening was investigated in depth, we identified the type of damage and measured its size and the crack tip radii. The morphology of the crack front was related to the fractographic study.Postprint (author's final draft

Wastewater Treatment by Advanced Oxidation Process and Their Worldwide Research Trends

Background: Water is a scarce resource and is considered a fundamental pillar of sustainable development. The modern development of society requires more and more drinking water. For this cleaner wastewater, treatments are key factors. Among those that exist, advanced oxidation processes are being researched as one of the sustainable solutions. The main objective of this manuscript is to show the scientific advances in this field. Methods: In this paper, a systematic analysis of all the existing scientific works was carried out to verify the evolution of this line of research. Results: It was observed that the three main countries researching this field are China, Spain, and the USA. Regarding the scientific collaboration between countries, three clusters were detected—one of Spain, one of China and the USA, and one of Italy and France. The publications are grouped around three types of water: industrial, urban, and drinking. Regarding the research, 15 clusters identified from the keywords analyzed the advanced oxidation process (alone or combined with biological oxidation) with the type of wastewater and the target pollutant, removal of which is intended. Finally, the most important scientific communities or clusters detected in terms of the number of published articles were those related to the elimination of pollutants of biological origin, such as bacteria, and of industrial nature, such as pesticides or pharmaceutical products

Astrocyte Clocks and Glucose Homeostasis

The endogenous timekeeping system evolved to anticipate the time of the day through the 24 hours cycle of the Earth’s rotation. In mammals, the circadian clock governs rhythmic physiological and behavioral processes, including the daily oscillation in glucose metabolism, food intake, energy expenditure, and whole-body insulin sensitivity. The results from a series of studies have demonstrated that environmental or genetic alterations of the circadian cycle in humans and rodents are strongly associated with metabolic diseases such as obesity and type 2 diabetes. Emerging evidence suggests that astrocyte clocks have a crucial role in regulating molecular, physiological, and behavioral circadian rhythms such as glucose metabolism and insulin sensitivity. Given the concurrent high prevalence of type 2 diabetes and circadian disruption, understanding the mechanisms underlying glucose homeostasis regulation by the circadian clock and its dysregulation may improve glycemic control. In this review, we summarize the current knowledge on the tight interconnection between the timekeeping system, glucose homeostasis, and insulin sensitivity. We focus specifically on the involvement of astrocyte clocks, at the organism, cellular, and molecular levels, in the regulation of glucose metabolismOB-M is supported with a Ramón y Cajal award (RYC2018‐026293‐I.) from the Ministerio de Ciencia, Innovación y Universidades of Spain; by Spanish Agencia Estatal de Investigación (PID2019-109556RB-I00) and the Xunta de Galicia-Consellería de Cultura, Educación e Ordenación Universitaria (ED431F 2020/009)S

Technological Advances in the Diagnosis and Management of Tinnitus

Tinnitus disorder is a bothersome perception of a composite noise or tone in the ears in the absence of an external source, associated with emotional distress, cognitive dysfunction, and/or autonomic arousal. Tinnitus frequently occurs as a symptom together with other hearing disorders (high-frequency hearing loss, Meniere’s disease, vestibular schwannoma), auditory pathway disorders (hyperacusis), mental disorders (anxiety, depression), vascular risk factors (high blood pressure, dyslipidemia), or neurological disorders (intracranial hypertension, migraine).La Caixa Foundation 100010434 LCF/PR/DE18/52010002European Commission 848261Andalusian Health Government RH-0150-202