The space density of z>4 blazars

High redshift blazars are an important class of Active Galactic Nuclei (AGN) that can provide an independent estimate of the supermassive black-hole mass function in high redshift radio-loud AGN without the bias due to absorption along the line-of-sight. Using the Cosmic Lens All Sky Survey (CLASS) we built a complete radio flux-limited sample of high redshift (z>4) blazars suitable for statistical studies. By combining dedicated optical observations and the SDSS spectroscopic database, we obtained a sample of 26 blazar candidates with a spectroscopic redshift above 4. On the basis of their radio spectrum we distinguish between blazars and QSO with a Gigahertz Peaked Spectrum (GPS) like spectrum. Out of the 18 confirmed blazars 14 constitute a completely identified, flux-limited sample down to a magnitude of 21 (AB). Using this complete sample we derive a space density of blazars with 4<z<5.5 of rho=0.13 (+0.05,-0.03) Gpc^-3. This is the first actual estimate of the blazar space density in this range of redshift. This value is in good agreement with the extrapolation of the luminosity function and cosmological evolution based on a sample of flat-spectrum radio quasars selected at lower redshifts and it is consistent with a cosmological evolution peaking at z$\sim$2 similar to radio-quiet QSO. We do not confirm, instead, the presence of a peak at z~4 in the space density evolution, recently suggested using an X-ray selected sample of blazars. It is possible that this extreme peak of the evolution is present only among the most luminous blazars.Comment: 14 pages, accepted for publication on MNRAS (https://doi.org/10.1093/mnras/sty3526

Procedimiento de extracción sanguínea y disminución de la ansiedad concomitante

En este trabajo se describe el procedimiento a seguir para la correcta extracción de muestras de sangre por venopunción, la ansiedad asociada que puede surgir en los momentos anteriores o durante la extracción sanguínea y métodos o técnicas para resolverlas

Phase tunability of group velocity by modulated-pump-forced coherent population oscillations

We propose a technique to obtain slow and fast light propagations based on coherent population oscillations forced by a modulated pump. This mechanism produces an enhancement of 1 order of magnitude of the delay or advancement of light signals. The relative phase between the pumps to the signal fields is used as a knob for changing light propagation from ultraslow group velocities to negative group velocities. The experimental realization of the phenomenon was carried out in an erbium-doped fiber amplifier at room temperature

Alcohol-related stimuli modulate functional connectivity during response inhibition in young binge drinkers

Binge drinking is a pattern of intermittent excessive alcohol consumption that is highly prevalent in young people. Neurocognitive dual-process models have described substance abuse and adolescence risk behaviours as the result of an imbalance between an overactivated affective-automatic system (related to motivational processing) and damaged and/or immature reflective system (related to cognitive control abilities). Previous studies have evaluated the reflective system of binge drinkers (BDs) through neutral response inhibition tasks and have reported anomalies in theta (4–8 Hz) and beta (12–30 Hz) bands. The present study aimed to investigate the influence of the motivational value of alcohol-related stimuli on brain functional networks devoted to response inhibition in young BDs. Sixty eight BDs and 78 control participants performed a beverage Go/NoGo task while undergoing electrophysiological recording. Whole cortical brain functional connectivity (FC) was evaluated during successful response inhibition trials (NoGo). BDs exhibited fast-beta and theta hyperconnectivity in regions related to cognitive control. These responses were modulated differently depending on the motivational content of the stimuli. The increased salience of alcohol-related stimuli may lead to overactivation of the affective-automatic system in BDs, and compensatory neural resources of the reflective system will thus be required during response inhibition. In BDs, inhibition of the response to alcohol stimuli may require higher theta FC to facilitate integration of information related to the task goal (withholding a response), while during inhibition of the response to no-alcoholic stimuli, higher fast-beta FC would allow to apply top-down inhibitory control of the information related to the prepotent responseFunding for this research was provided by the Plan Nacional Sobre Drogas (PNSD 2015/034) and Ministerio de Economía, Industria y Competitividad together with European Regional Development Fund (PSI2015-70525-P), Ministerio de Ciencia e Innovación (PID2020-113487RB-I00) and Xunta de Galicia (ED431C 2917/06). JBR was supported by the FPU program (FPU2015-03591) of the Spanish Ministry of Education, Culture and Sports. SSS was supported by a predoctoral fellowship from the Spanish Ministerio de Economía y Competitividad (BES-2016-076298).S

Estructuras y liderazgo en cuatro redes españolas dedicadas al tráfico de drogas

Este artículo tiene como objetivo estudiar, desde la perspectiva del análisis de redes sociales, la estructura, las personas más relevantes y las posiciones jerárquicas de los miembros de cuatro grupos involucrados en el tráfico de cocaína de nivel medio (mayoristas). Con este fin, se ha recabado información de los archivos policiales sobre cuatro operaciones criminales, a través de un cuestionario de 76 variables, divididas en cuatro áreas principales: las características de la organización, el mercado ilícito, actividades instrumentales o transversales y el perfil de los miembros del grupo. También se ha recogido información sobre contactos telefónicos y reuniones registradas en la investigación policial, con el fin de analizar la organización desde la perspectiva del análisis de redes sociales. Las cuatro redes han sido examinadas teniendo en cuenta tres aspectos: la estructura, los actores centrales e intermediarios y sus posiciones jerárquicas. Los resultados muestran diferencias con los enfoques tradicionales jerárquicos y avanzan posibles aplicaciones para la investigación y la inteligencia criminalThe aim of the paper is to present the findings of a research which targets the application of social network analysis (SNA) perspective to data coming from police investigations about four middle level drug trafficking organizations. For that purpose, we have collected information from police files of 4 investigations of criminal organizations by means of a questionnaire of 76 variables divided in four main areas: features of the organization, illicit market, instrumental or transversal activities and profile of members. Additionally, we have gathered information about wiretappings and meetings registered by the criminal investigation with the intention to analyze the organization under SNA perspective. The four networks have been analyzed taking into account three dimensions: a) structure and inside roles; b) powerful members; c) hierarchical positions. Results show up differences between networks and advantages of SNA perspective in comparison with more hierarchical approaches and further applications for investigation and intelligence purpose

Programa de rehabilitación multimodal en cirugía pancreática

La rehabilitación multimodal comprende un conjunto multidisciplinar de intervenciones perioperatorias cuyo objetivo es mejorar losresultados quirúrgicos y disminuir las complicaciones mediante la reducción del estrés quirúrgico y el control del dolor. El objetivo de este trabajo es analizar los resultados de la aplicación de los programas ERAS en cirugía pancreática y compararlos con los resultados obtenidos tras la aplicación de los cuidados tradicionales. Para ello, se ha llevado a cabo una revisión en distintas bases de datos, a través de la herramienta Alcorze, de estudios sobre la aplicación del protocolo ERAS en cirugía pancreática en comparación con los cuidados tradicionales. Se han seleccionado y analizado 13 estudios con un total de 13916 pacientes. La aplicación de los protocolos ERAS en cirugía pancreática se asocia con una reducción del tiempo de estancia hospitalaria y los costes sanitarios, sin aumentar la tasa de mortalidad, reingresos o complicaciones.<br /

Optical pumping of a single hole spin in a p-doped quantum dot coupled to a metallic nanoparticle

The preparation of quantum states with a defined spin is analyzed in a hybrid system consisting of a p-doped semiconductor quantum dot (QD) coupled to a metallic nanoparticle. The quantum dot is described as a four-level atom-like system using the density matrix formalism. The lower levels are Zeeman-split hole spin states and the upper levels correspond to positively charged excitons containing a spin-up, spin-down hole pair and a spin electron. A metallic nanoparticle with spheroidal geometry is placed in close proximity to the quantum dot, and its effects are considered in the quasistatic approximation. A linearly polarized laser field drives two of the optical transitions of the QD and produces localized surface plasmons in the nanoparticle which act back upon the QD. The frequencies of these localized plasmons are very different along the two principal axes of the nanoparticle, thus producing an anisotropic modification of the spontaneous emission rates of the allowed optical transitions which is accompanied by local-field corrections. This effect translates into a preferential acceleration of some of the optical pathways and therefore into a fast initialization of the QD by excitation with a short optical pulse. The population transfer between the lower levels of the QD and the fidelity is analyzed as a function of the nanoparticle's aspect ratio, the external magnetic field, and the Rabi frequency of the driving field. It is also shown that the main effect of the local-field corrections is a lengthening of the time elapsed to reach the steady-state. The hole spin is predicted to be successfully cooled from 5 to 0.04 K at a magnetic field of 4.6 T applied in the Voigt geometry

Propagation-induced transition from slow to fast light in highly doped erbium fibers

We analyze the propagation regime of an amplitude-modulated 1536 nm signal when traveling along a highly doped erbium fiber pumped at 977 nm as a function of the fiber length. A propagation-induced transition from superluminal to subluminal propagation takes place along the fiber length which allows a change in regime solely based upon increasing the signal modulation frequency. This peculiar behavior is due to the interplay between pump absorption and pump-power broadening of the spectral hole induced by coherent population oscillations. The effect of ion density on this frequency-dependent regime change has been investigated