Powering AGNs with super-critical black holes

We propose a novel mechanism for powering the central engines of Active Galactic Nuclei through super-critical (type II) black hole collapse. In this picture, ~$10^3 M_\odot$ of material collapsing at relativistic speeds can trigger a gravitational shock, which can eject a large percentage of the collapsing matter at relativistic speeds, leaving behind a "light" black hole. In the presence of a poloidal magnetic field, the plasma collimates along two jets, and the associated electron synchrotron radiation can easily account for the observed radio luminosities, sizes and durations of AGN jets. For Lorentz factors of order 100 and magnetic fields of a few hundred $\mu G$, synchrotron electrons can shine for $10^6$ yrs, producing jets of sizes of order 100 kpc. This mechanism may also be relevant for Gamma Ray Bursts and, in the absence of magnetic field, supernova explosions.Comment: 4 pages, 1 figur

Pharmacotherapy in paediatric epilepsy: from trial and error to rational drug and dose selection – a long way to go

Whereas ongoing efforts in epilepsy research focus on the underlying disease processes, the lack of a physiologically-based rationale for drug and dose selection contributes to inadequate treatment response in children. In fact, limited information on the interindividual variation in pharmacokinetics and pharmacodynamics of anti-epileptic drugs (AEDs) in children drive prescription practice, which relies primarily on dose regimens according to a mg/kg basis. Such practice has evolved despite advancements in paediatric pharmacology showing that growth and maturation processes do not correlate linearly with changes in body size. Areas covered: In this review we aim to provide 1) a comprehensive overview of the sources of variability in the response to AEDs, 2) insight into novel methodologies to characterise such variation and 3) recommendations for treatment personalisation. Expert Opinion: The use of pharmacokinetic-pharmacodynamic principles in clinical practice is hindered by the lack of biomarkers and by practical constraints in the evaluation of polytherapy. The identification of biomarkers and their validation as tools for drug development and therapeutics will require some time. Meanwhile, one should not miss the opportunity to integrate the available pharmacokinetic data with modelling and simulation concepts to prevent further delays in the development of personalised treatments for paediatric patients

Changes in marine turbot (Scophthalmus maximus) epidermis and skin mucus composition during development from bilateral larvae to juvenile flat fish

Alike other flat fish, marine turbot has the particularity that changes from larvae with bilateral symmetry to adult with asymmetry, in terms of the position of the eyes. As expected, the skin configuration of this species is also affected by the development and transformation suffered by fish during metamorphosis. In this context, changes in the epidermis of marine turbot were studied using conventional staining and histochemical techniques using six lectins (UEA-I, PNA, RCA-I, WGA, Con A and SBA). During development from larvae to juvenile (3–300 days post-hatching), the epidermis increased in both thickness and the number of cell layers. In fact, the simple cuboidal epithelium observed in larvae at day 3 already became stratified at days 10–12, which sequentially increase in thickness with fish development. Turbot epidermis is composed basically of four cell types: epithelial and mucous or secretory cells that are present through the development, and pigmented cells and a type that the authors described as club-like cells that appear during and post-metamorphosis. The Alcian blue-periodic acid Schiff (AB-PAS) histochemical method revealed the presence of neutral glycoconjugates in mucous and club-like cells at post-metamorphic stages of fish. Accordingly, lectin analysis showed mucous cells containing glycoproteins rich in fucose (UEA-I labelling) and glycoconjugates rich in the sequence galactose-N-acetyl galactosamine (PNA and RCA-I labelling) when this cell type appears. Interestingly, melanophores were observed in the dorsal epidermis of post-metamorphic juveniles. This type of cell contains a black-to-brown pigment that provides the skin the typical colour of this fish species. Changes in mucous coat composition were observed during fish development, which was attributed to different roles of the glycoconjugates.Ministerio de Ciencia e Innovación | Ref. CGL 2009-07904Universidade de Vigo/ CISU

OPTICAL SPECTROSCOPIC OBSERVATIONS OF GAMMA-RAY BLAZAR CANDIDATES. VI. FURTHER OBSERVATIONS FROM TNG, WHT, OAN, SOAR, AND MAGELLAN TELESCOPES

Indexación: Web of ScienceBlazars, one of the most extreme classes of active galaxies, constitute so far the largest known population of.-ray sources, and their number is continuously growing in the Fermi catalogs. However, in the latest release of the Fermi catalog there is still a large fraction of sources that are classified as blazar candidates of uncertain type (BCUs) for which optical spectroscopic observations are necessary to confirm their nature and their associations. In addition, about one-third of the gamma-ray point sources listed in the Third Fermi-LAT Source Catalog (3FGL) are still unassociated and lacking an assigned lower-energy counterpart. Since 2012 we have been carrying out an optical spectroscopic campaign to observe blazar candidates to confirm their nature. In this paper, the sixth of the series, we present optical spectroscopic observations for 30 gamma-ray blazar candidates from different observing programs we carried out with the Telescopio Nazionale Galileo, William Herschel Telescope, Observatorio Astronomico Nacional, Southern Astrophysical Research Telescope, and Magellan. Telescopes. We found that 21 out of 30 sources investigated are BL Lac objects, while the remaining targets are classified as flat-spectrum radio quasars showing the typical broad emission lines of normal quasi-stellar objects. We conclude that our selection of gamma-ray blazar. candidates based on their multifrequency properties continues to be a successful way to discover potential low-energy counterparts of the Fermi. unidentified gamma-ray sources and to confirm the nature of BCUs.http://iopscience.iop.org/article/10.3847/0004-6256/151/4/95/met

Dexmedetomidine Clearance Decreases with Increasing Drug Exposure:Implications for Current Dosing Regimens and Target-controlled Infusion Models Assuming Linear Pharmacokinetics

Background: Numerous pharmacokinetic models have been published aiming at more accurate and safer dosing of dexmedetomidine. The vast majority of the developed models underpredict the measured plasma concentrations with respect to the target concentration, especially at plasma concentrations higher than those used in the original studies. The aim of this article was to develop a dexmedetomidine pharmacokinetic model in healthy adults emphasizing linear versus nonlinear kinetics. Methods: The data of two previously published clinical trials with stepwise increasing dexmedetomidine target-controlled infusion were pooled to build a pharmacokinetic model using the NONMEM software package (ICON Development Solutions, USA). Data from 48 healthy subjects, included in a stratified manner, were utilized to build the model. Results: A three-compartment mamillary model with nonlinear elimination from the central compartment was superior to a model assuming linear pharmacokinetics. Covariates included in the final model were age, sex, and total body weight. Cardiac output did not explain between-subject or within-subject variability in dexmedetomidine clearance. The results of a simulation study based on the final model showed that at concentrations up to 2 ng center dot ml(-1), the predicted dexmedetomidine plasma concentrations were similar between the currently available Hannivoort model assuming linear pharmacokinetics and the nonlinear model developed in this study. At higher simulated plasma concentrations, exposure increased nonlinearly with target concentration due to the decreasing dexmedetomidine clearance with increasing plasma concentrations. Simulations also show that currently approved dosing regimens in the intensive care unit may potentially lead to higher-than-expected dexmedetomidine plasma concentrations. Conclusions: This study developed a nonlinear three-compartment pharmacokinetic model that accurately described dexmedetomidine plasma concentrations. Dexmedetomidine may be safely administered up to target-controlled infusion targets under 2 ng center dot ml(-1) using the Hannivoort model, which assumed linear pharmacokinetics. Consideration should be taken during long-term administration and during an initial loading dose when following the dosing strategies of the current guidelines

The discovery of the most UV-Lya luminous star-forming galaxy: a young, dust- and metal-poor starburst with QSO-like luminosities

We report the discovery of BOSS-EUVLG1 at z=2.469, by far the most luminous, almost un-obscured star-forming galaxy known at any redshift. First classified as a QSO within the Baryon Oscillation Spectroscopic Survey, follow-up observations with the Gran Telescopio Canarias reveal that its large luminosity, MUV = -24.40 and log(L_Lya/erg s-1) = 44.0, is due to an intense burst of star-formation, and not to an AGN or gravitational lensing. BOSS-EUVLG1 is a compact (reff = 1.2 kpc), young (4-5 Myr) starburst with a stellar mass log(M*/Msun) = 10.0 +/- 0.1 and a prodigious star formation rate of ~1000 Msun yr-1. However, it is metal- and dust-poor (12+log(O/H) = 8.13 +/- 0.19, E(B-V) = 0.07, log(LIR/LUV) < -1.2), indicating that we are witnessing the very early phase of an intense starburst that has had no time to enrich the ISM. BOSS-EUVLG1 might represent a short-lived (<100 Myrs), yet important phase of star-forming galaxies at high redshift that has been missed in previous surveys. Within a galaxy evolutionary scheme, BOSS-EUVLG1 could likely represent the very initial phases in the evolution of massive quiescent galaxies, even before the dusty star-forming phase.Comment: 6 pages, 3 figures, 1 table. Accepted for publication in MNRAS Letter

J-PLUS: analysis of the intracluster light in the Coma cluster

The intracluster light (ICL) is a luminous component of galaxy clusters composed of stars that are gravitationally bound to the cluster potential but do not belong to the individual galaxies. Previous studies of the ICL have shown that its formation and evolution are intimately linked to the evolutionary stage of the cluster. Thus, the analysis of the ICL in the Coma cluster will give insights into the main processes driving the dynamics in this highly complex system. Using a recently developed technique, we measure the ICL fraction in Coma at several wavelengths, using the J-PLUS unique filter system. The combination of narrow- and broadband filters provides valuable information on the dynamical state of the cluster, the ICL stellar types, and the morphology of the diffuse light. We use the Chebyshev-Fourier Intracluster Light Estimator (CICLE) to disentangle the ICL from the light of the galaxies, and to robustly measure the ICL fraction in seven J-PLUS filters. We obtain the ICL fraction distribution of the Coma cluster at different optical wavelengths, which varies from $\sim 7\%-21\%$, showing the highest values in the narrowband filters J0395, J0410, and J0430. This ICL fraction excess is distinctive pattern recently observed in dynamically active clusters (mergers), indicating a higher amount of bluer stars in the ICL compared to the cluster galaxies. Both the high ICL fractions and the excess in the bluer filters are indicative of a merging state. The presence of younger/lower-metallicity stars the ICL suggests that the main mechanism of ICL formation for the Coma cluster is the stripping of the stars in the outskirts of infalling galaxies and, possibly, the disruption of dwarf galaxies during past/ongoing mergers.Comment: 10 pages, 3 figures, 1 table. Accepted for publication in A&

Utilización de un recinto de la Universidad Nacional de Luján como modelo experimental y demostrativo para la aplicación de técnicas de acondicionamiento natural de bajo costo

Un pequeño recinto dentro de la Universidad Nacional de Luján es utilizado por el equipo de trabajo desde hace diez años como modelo experimental y demostrativo para la aplicación de técnicas de acondicionamiento ambiental de bajo costo y mínimo consumo energético. Con anterioridad al inicio de esta experiencia, el recinto era conocido por su pésima respuesta ambiental, sobre todo en el período cálido. Sobre el mismo fueron aplicadas con el tiempo sucesivas mejoras siguiendo una metodología que apuntaba tanto a lo experimental como a lo pedagógico y demostrativo, dada la similitud constructiva que el recinto mostraba con las viviendas precarias que autoconstruyen sectores de menores recursos. En el trabajo se muestran las sucesivas técnicas utilizadas, los resultados parciales medidos como consecuencia de las mismas, hasta llegar al momento actual en que se demuestra la muy satisfactoria respuesta alcanzada en relación con el confort ambiental interior para cualquier época del año.For ten years, a research team has been using a small room at the National University of Lujan as an experimental demonstration model for the application of low-cost environmental conditioning energy-efficient techniques. Before starting this experience, the building was characterized for its poor environmental conditions, especially during the warm season. Over time, successive improvements were applied upon it following not only an experimental methodology but also educational and demonstrative ones, since this room had been made with similar building materials to the ones used in poor-quality housing of low-income self-builders. This paper shows the consecutive techniques applied and the measurement of the partial results obtained from the application of these techniques till the present time, which demonstrates a very satisfactory response related to the indoor environmental quality at any time of the year.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Using internet enabled mobile devices and social networking technologies to promote exercise as an intervention for young first episode psychosis patients

<p>Abstract</p> <p>Background</p> <p>Young people with first episode psychosis are at an increased risk for a range of poor health outcomes. In contrast to the growing body of evidence that suggests that exercise therapy may benefit the physical and mental health of people diagnosed with schizophrenia, there are no studies to date that have sought to extend the use of exercise therapy among patients with first episode psychosis. The aim of the study is to test the feasibility and acceptability of an exercise program that will be delivered via internet enabled mobile devices and social networking technologies among young people with first episode psychosis.</p> <p>Methods/Design</p> <p>This study is a qualitative pilot study being conducted at Orygen Youth Health Research Centre in Melbourne, Australia. Participants are young people aged 15-24 who are receiving clinical care at a specialist first episode psychosis treatment centre. Participants will also comprise young people from the general population. The exercise intervention is a 9-week running program, designed to gradually build a person's level of fitness to be able to run 5 kilometres (3 miles) towards the end of the program. The program will be delivered via an internet enabled mobile device. Participants will be asked to post messages about their running experiences on the social networking website, and will also be asked to attend three face-to-face interviews.</p> <p>Discussion</p> <p>This paper describes the development of a qualitative study to pilot a running program coupled with the use of internet enabled mobile devices among young people with first episode psychosis. If the program is found to be feasible and acceptable to patients, it is hoped that further rigorous evaluations will ultimately lead to the introduction of exercise therapy as part of an evidence-based, multidisciplinary approach in routine clinical care.</p

Detection of helicoidal motion in the optical jet of PKS 0521-365

The jet activity of active galactic nuclei (AGNs), and its interaction with the interstellar medium, may play a pivotal role in the processes that regulate the growth and star formation of its host galaxy. Observational evidence that pinpoints the conditions of such interaction is paramount to unveil the physical processes involved. We report on the discovery of extended emission-line regions exhibiting an S-shaped morphology along the optical jet of the radioloud AGN PKS 0521-365 (z = 0.055), by using long-slit spectroscopic observations obtained with FOcal Reducer/low dispersion Spectrograph 2 on the Very Large Telescope. The velocity pattern derived from the [O II].3727 angstrom, H beta lambda 4861 angstrom and [O III] lambda lambda 4959, 5007 angstrom emission lines is well fitted by a sinusoidal function of the form: v(r) = alpha r(1/2)sin(beta r(1/2) + gamma), suggesting helicoidal motions along the jet up to distances of 20 kpc. We estimate a lower limit for the mass of the outflowing ionized gas along the jet of similar to 10(4)M(circle dot). Helical magnetic fields and jet precession have been proposed to explain helicoidal paths along the jet at pc scales; nevertheless, it is not clear yet whether these hypotheses may hold at kpc scales