Atmospheric muon background in the ANTARES detector

An evaluation of the background due to atmospheric muons in the ANTARES high energy neutrino telescope is presented. Two different codes for atmospheric shower simulation have been used. Results from comparisons between these codes at sea level and detector level are presented. The first results on the capability of ANTARES to reject this class of background are given.Comment: 4 pages, 4 figures, To appear in Proceedings of the 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, 3 - 10 Aug 200

Nuclear Track Detectors for Environmental Studies and Radiation Monitoring

Several improvements were made for Nuclear Track Detectors (NTDs) used for environmental studies and for particle searches. A new method was used to determine the bulk etch rate of CR39 and Makrofol NTDs. It is based on the simultaneous measurement of the diameter and of the height of etch-pit cones caused by relativistic heavy ions (158 A GeV Pb(82+) and In(49+) ions) and their fragments. The use of alcohol in the etching solution improves the surface quality of NTDs and it raises their thresholds. The detectors were used for the determination of nuclear fragmentation cross sections of Iron and Silicon ions of 1.0 and 0.41 GeV/nucleon. These measurements are important for the determination of doses in hadron therapy and for doses received by astronauts. The detectors were also used in the search of massive particles in the cosmic radiation, for the determination of the mass spectrum of cosmic rays and for the evaluation of Po(210) alpha decay and of natural radon concentrations.Comment: 7 pages, 5 EPS figures. Presented at the 10th Topical Seminar on Innovative Particle and Radiation Detectors, 1-5 October 2006, Siena, Ital

Evaluation of metaperception of goal orientation and moral functioning in soccer spectators

La violencia en el fútbol es un grave problema social. Algunas de sus manifestaciones están relacionadas con el espectáculo deportivo y su tratamiento en los medios de comunicación. La finalidad de este estudio ha sido analizar las propiedades psicométricas de dos escalas en español que miden la meta-percepción de orientación de meta y el funcionamiento moral en espectadores de fútbol. Los participantes fueron estudiantes universitarios (N = 616) que completaron cuestionarios valorando el tiempo dedicado al consumo de programas deportivos sobre fútbol, la meta-percepción de orientación de meta y el funcionamiento moral. Las escalas definitivas mostraron una adecuada validez de constructo, validez convergente y validez concurrente. Estos resultados indican que las nuevas escalas poseen adecuadas propiedades psicométricas, lo que permite una evaluación válida y fiable que mejore el entendimiento de los procesos que operan en los espectadores de deportes como el fútbolSoccer violence is a serious social problem. Some of its manifestations are related to competitive sport and its treatment by the mass media. The purpose of this study was to analyze the psychometric properties of two Spanish scales which measure the metaperception of goal orientation and moral functioning in soccer spectators. Participants (N = 616) reported the time spent viewing soccer sport programming, and rated metaperception of goal orientation and moral functioning. The scales exhibited adequate construct, convergent and concurrent validity. These results indicate that the new scales have adequate psychometric properties, allowing a valid and reliable assessment in order to explain the processes that take place in sport spectators like soccer viewer

Surface-acoustic-wave driven planar light-emitting device

Electroluminescence emission controlled by means of surface acoustic waves (SAWs) in planar light-emitting diodes (pLEDs) is demonstrated. Interdigital transducers for SAW generation were integrated onto pLEDs fabricated following the scheme which we have recently developed. Current-voltage, light-voltage and photoluminescence characteristics are presented at cryogenic temperatures. We argue that this scheme represents a valuable building block for advanced optoelectronic architectures

Nuclear Track Detectors. Searches for Exotic Particles

We used Nuclear Track Detectors (NTD) CR39 and Makrofol for many purposes: i) Exposures at the SPS and at lower energy accelerator heavy ion beams for calibration purposes and for fragmentation studies. ii) Searches for GUT and Intermediate Mass Magnetic Monopoles (IMM), nuclearites, Q-balls and strangelets in the cosmic radiation. The MACRO experiment in the Gran Sasso underground lab, with ~1000 m^2 of CR39 detectors (plus scintillators and streamer tubes), established an upper limit for superheavy GUT poles at the level of 1.4x10^-16 cm^-2 s^-1 sr^-1 for 4x10^-5 <beta<1. The SLIM experiment at the high altitude Chacaltaya lab (5230 m a.s.l.), using 427 m^2 of CR39 detectors exposed for 4.22 y, gave an upper limit for IMMs of ~1.3x10^-15 cm^-2 s^-1 sr^-1. The experiments yielded interesting upper limits also on the fluxes of the other mentioned exotic particles. iii) Environmental studies, radiation monitoring, neutron dosimetry.Comment: Talk given at "New Trends In High-Energy Physics" (experiment, phenomenology, theory) Yalta, Crimea, Ukraine, September 27-October 4, 200

Motivos por los que los estudiantes universitarios no practican deporte

Este estudio examinó las causas por las que los jóvenes universitarios no practican deporte. Los participantes fueron estudiantes de la Universidad de Oviedo (N = 1.916). Los resultados mostraron que aquellos que manifiestan motivos de carácter extrínseco para explicar su desvinculación activa del deporte, son estudiantes que, a pesar de todo, siguen estando interesados y predispuestos a practicar (no-practica de carácter reluctante, o también de una no-práctica contra el corazón, con mayores posibilidades de ser captados o reintegrados al deporte). Mientras que los que aducen motivos de carácter intrínseco son universitarios que han dejado de estar interesados por el deporte, les ha dejado de gustar, les resulta aburrido, etc. (no-practica por descontento, con menores posibilidades de ser captados o reincorporados). Observamos que estas dos direcciones se relacionan con el género, la percepción de las repercusiones de la práctica deporte en los estudios y la importancia que asignan al deporte en la vida universitaria. Finalmente se discuten sus implicaciones.This papers presents the reasons why university students say that they don’t practice sports. The information comes from a survey answered by students from the Universidad de Oviedo. The results show that those students who talk about external reasons to quit from sports (reluctant non-practice o against the sentiments non-practice) are students that keep an interest in sports and, eventually, could come back to sports activities. They are people with some possibilities to be active again in sports practice. Whereas those students who sustain internal reasons to quit from sports practice are people who has not interest at all in sports. They don’t like it anymore or they find it boring (non-practice by dissatisfaction). They are people with less possibilities to come again to sports practice. We can see that in both groups there are meaningful variables such as sex, students perception of the impact of sports in academic results and the importance that they give to sports in university life. The paper concludes with the discussion of the implications that the analysed classifications can have in the increase of university sports practice

Reflectionless tunneling in planar Nb/GaAs hybrid junctions

Reflectionless-tunneling was observed in Nb/GaAs superconductor/semiconductor junctions fabricated through a two-step procedure. First, periodic $\delta$-doped layers were grown by molecular beam epitaxy near the GaAs surface, followed by an As cap layer to protect the surface during {\it ex-situ} transfer. Second, Nb was deposited by dc-magnetron sputtering onto the GaAs(001) 2 $\times$ 4 surface {\it in-situ} after thermal desorption of the cap layer. The magnetotransport behavior of the resulting hybrid junctions was successfully analyzed within the random matrix theory of phase-coherent Andreev transport. The impact of junction morphology on reflectionless tunneling and the applicability of the fabrication technique to the realization of complex superconductor/semiconductor mesoscopic systems are discussed.Comment: 10 pages, 3 figures, to be published in Appl. Phys. Let

High frequency mechanical excitation of a silicon nanostring with piezoelectric aluminum nitride layers

A strong trend for quantum based technologies and applications follows the avenue of combining different platforms to exploit their complementary technological and functional advantages. Micro and nano-mechanical devices are particularly suitable for hybrid integration due to the easiness of fabrication at multi-scales and their pervasive coupling with electrons and photons. Here, we report on a nanomechanical technological platform where a silicon chip is combined with an aluminum nitride layer. Exploiting the AlN piezoelectricity, Surface Acoustic Waves are injected in the Si layer where the material has been localy patterned and etched to form a suspended nanostring. Characterizing the nanostring vertical displacement induced by the SAW, we found an external excitation peak efficiency in excess of 500 pm/V at 1 GHz mechanical frequency. Exploiting the long term expertise in silicon photonic and electronic devices as well as the SAW robustness and versatility, our technological platform represents a strong candidate for hybrid quantum systems

Bulk Etch Rate Measurements and Calibrations of Plastic Nuclear Track Detectors

New calibrations of CR39 and Makrofol nuclear track detectors have been obtained using 158 A GeV Pb (82+) and In (49+) ions; a new method for the bulk etch rate determination, using both cone height and base diameter measurements was developed. The CR39 charge resolution based on the etch-pit base area measurement is adequate to identify nuclear fragments in the interval 7 <= Z/beta <= 49. For CR39 the detection threshold is at REL~50 MeV cm^2/g, corresponding to a nuclear fragment with Z/beta~7. Base cone area distributions for Makrofol foils exposed to Pb (82+) ions have shown for the first time all peaks due to nuclear fragments with Z > 50; the distribution of the etched cone heights shows well separated individual peaks for Z/beta = 78 - 83 (charge pickup). The Makrofol detection threshold is at REL 2700 MeV cm^2/g, corresponding to a nuclear fragment with Z/beta~50.Comment: 11 pages, 5 EPS figures. Submitted to Nucl. Instr. Meth.