916 research outputs found
Transiting Exoplanets with JWST
The era of exoplanet characterization is upon us. For a subset of exoplanets
-- the transiting planets -- physical properties can be measured, including
mass, radius, and atmosphere characteristics. Indeed, measuring the atmospheres
of a further subset of transiting planets, the hot Jupiters, is now routine
with the Spitzer Space Telescope. The James Webb Space Telescope (JWST) will
continue Spitzer's legacy with its large mirror size and precise thermal
stability. JWST is poised for the significant achievement of identifying
habitable planets around bright M through G stars--rocky planets lacking
extensive gas envelopes, with water vapor and signs of chemical disequilibrium
in their atmospheres. Favorable transiting planet systems, are, however,
anticipated to be rare and their atmosphere observations will require tens to
hundreds of hours of JWST time per planet. We review what is known about the
physical characteristics of transiting planets, summarize lessons learned from
Spitzer high-contrast exoplanet measurements, and give several examples of
potential JWST observations.Comment: 22 pages, 11 figures. In press in "Astrophysics in the Next Decade:
JWST and Concurrent Facilities, Astrophysics & Space Science Library,
Thronson, H. A., Tielens, A., Stiavelli, M., eds., Springer: Dordrecht
(2008)." The original publication will be available at
http://www.springerlink.co
Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum
We report a first measurement for ultra-high energy cosmic rays of the
correlation between the depth of shower maximum and the signal in the water
Cherenkov stations of air-showers registered simultaneously by the fluorescence
and the surface detectors of the Pierre Auger Observatory. Such a correlation
measurement is a unique feature of a hybrid air-shower observatory with
sensitivity to both the electromagnetic and muonic components. It allows an
accurate determination of the spread of primary masses in the cosmic-ray flux.
Up till now, constraints on the spread of primary masses have been dominated by
systematic uncertainties. The present correlation measurement is not affected
by systematics in the measurement of the depth of shower maximum or the signal
in the water Cherenkov stations. The analysis relies on general characteristics
of air showers and is thus robust also with respect to uncertainties in
hadronic event generators. The observed correlation in the energy range around
the `ankle' at differs significantly from
expectations for pure primary cosmic-ray compositions. A light composition made
up of proton and helium only is equally inconsistent with observations. The
data are explained well by a mixed composition including nuclei with mass . Scenarios such as the proton dip model, with almost pure compositions, are
thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray
flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report
Numbe
The exposure of the hybrid detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays.
It consists of a surface array to measure secondary particles at ground level
and a fluorescence detector to measure the development of air showers in the
atmosphere above the array. The "hybrid" detection mode combines the
information from the two subsystems. We describe the determination of the
hybrid exposure for events observed by the fluorescence telescopes in
coincidence with at least one water-Cherenkov detector of the surface array. A
detailed knowledge of the time dependence of the detection operations is
crucial for an accurate evaluation of the exposure. We discuss the relevance of
monitoring data collected during operations, such as the status of the
fluorescence detector, background light and atmospheric conditions, that are
used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
Advanced functionality for radio analysis in the Offline software framework of the Pierre Auger Observatory
The advent of the Auger Engineering Radio Array (AERA) necessitates the
development of a powerful framework for the analysis of radio measurements of
cosmic ray air showers. As AERA performs "radio-hybrid" measurements of air
shower radio emission in coincidence with the surface particle detectors and
fluorescence telescopes of the Pierre Auger Observatory, the radio analysis
functionality had to be incorporated in the existing hybrid analysis solutions
for fluoresence and surface detector data. This goal has been achieved in a
natural way by extending the existing Auger Offline software framework with
radio functionality. In this article, we lay out the design, highlights and
features of the radio extension implemented in the Auger Offline framework. Its
functionality has achieved a high degree of sophistication and offers advanced
features such as vectorial reconstruction of the electric field, advanced
signal processing algorithms, a transparent and efficient handling of FFTs, a
very detailed simulation of detector effects, and the read-in of multiple data
formats including data from various radio simulation codes. The source code of
this radio functionality can be made available to interested parties on
request.Comment: accepted for publication in NIM A, 13 pages, minor corrections to
author list and references in v
Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory
We present the results of searches for dipolar-type anisotropies in different
energy ranges above eV with the surface detector array of
the Pierre Auger Observatory, reporting on both the phase and the amplitude
measurements of the first harmonic modulation in the right-ascension
distribution. Upper limits on the amplitudes are obtained, which provide the
most stringent bounds at present, being below 2% at 99% for EeV
energies. We also compare our results to those of previous experiments as well
as with some theoretical expectations.Comment: 28 pages, 11 figure
Soccer and homosexuality: the conflicts that lie within the affective game of the coach-adolescent athlete relationship
Discussions regarding homosexuality within a sports context are mediated by emotional nuances, especially in the world of soccer, where practitioners are required to have attributes such as strength, masculinity and aggressiveness. As a consequence, this work aimed to analyze the symbolic representation of homosexual relationships between
adolescent soccer players and their coaches; and, furthermore, to understand the intention behind homoerotic relationships that are established between members of the management team and its players. In this study, researchers used the life history methodology, with participation from three adolescent athletes, ages 14, 15 and 16, and three former athletes, ages 26, 28 and 45, who we called speakers. Based on the collection and analysis of research participantsâ testimonies, homosexual relations were found to have occurred between athletes and coaches, or between athletes and other members of the management team, as a part of a âsocial contractâ that is exclusively linked to their professional objectives. These relationships appear to be purely objective; authentic affective links are absent, due apparently to the transient nature of the athletes in these groups. Too, this context is usually marked by the athleteâs physical and emotional vulnerability, and the agreements he makes within this context are accompanied with moral dilemmas, because such adolescents idealize the coach as a paternal archetype.âFutebol e homossexualidade: Os conflitos que se encontram dentro do jogo afetivo da relação treinador-atleta
adolescente.â As discussĂ”es a respeito da homossexualidade no contexto esportivo sĂŁo mediadas por nuanças emocionais,
especialmente no mundo do futebol que exige de seus praticantes atributos de força, virilidade e agressividade. Por este
motivo este trabalho teve como objetivos diagnosticar existĂȘncia de relaçÔes homossexuais entre atletas adolescentes da
modalidade de futebol e seus técnicos e sua representação simbólica e ainda, compreender a intencionalidade das relaçÔes
homoafetivas que se estabelecem entre componentes da equipe diretiva e os jogadores. Esta pesquisa Ă© de natureza qualitativa
e a tĂ©cnica adotada foi a âhistĂłria de vidaâ e a participação de trĂȘs atletas adolescentes em atividade, com idade de
14, 15 e 16 anos e trĂȘs ex-atletas profissionais, com idades 26, 28 e 45 anos serviram de base metodolĂłgica. A partir da
anålise e tratamento dos depoimentos verificou-se que ocorreram relaçÔes homossexuais nas categorias de base envolvendo
técnico e atleta, ou com outros membros da equipe diretiva, como parte dos contratos sociais, ligados exclusivamente a
objetivos profissionais. Estas relaçÔes parecem ser puramente objetais, nĂŁo parecendo existir vĂnculos afetivos duradouros,
aparentemente, devido à natureza transitória de atletas nesses grupos. Também, nesses ambientes, muitas vezes marcados
pela vulnerabilidade fĂsica e emocional dos atletas, os acertos para as relaçÔes homossexuais sĂŁo permeadas por dilemas
morais, tendo em vista que os atletas adolescentes idealizam o treinador como o arquĂ©tipo paterno ideal.âEl fĂștbol y la homosexualidad: Los conflictos que se encuentran dentro del juego afectivo de la relaciĂłn
atleta-entrenador de los adolescentes.â Las discusiones sobre la homosexualidad en contexto deportivo estĂĄn mediadas por
matices emocionales, sobre todo en el mundo del fĂștbol que exige a sus jugadores atributos como la fuerza, la virilidad y los jugadores. En este estudio, los investigadores utilizaron la metodologĂa de la historia de vida, con la participaciĂłn de
tres atletas adolescentes, con 14, 15 y 16 años, y tres ex atletas con 26, 28 y 45 años, que llamamos âoradoresâ. Basado
en la recogida y anĂĄlisis de testimonios de participantes en la investigaciĂłn, se encontrĂł que las relaciones homosexuales
que se han producido entre los atletas y entrenadores, o entre atletas y otros miembros del equipo de gestiĂłn, son como
parte de un âcontrato socialâ que estĂĄ vinculado exclusivamente a sus objetivos profesionales. Estas relaciones parecen
ser solamente como un objeto; porque a veces no hay vĂnculos afectivos autĂ©nticos, debido aparentemente a la naturaleza
transitoria de los atletas en estos grupos. Demasiado, este contexto es generalmente marcado por la vulnerabilidad fĂsica
y emocional del deportista, y los acuerdos que hace dentro de este contexto se acompañan con dilemas morales, debido
a que tales adolescentes idealizan el entrenador como un arquetipo paterno.
la agresividad. Por lo tanto, este estudio tuvo como objetivo diagnosticar la existencia de relaciones homosexuales entre
adolescentes atletas de fĂștbol y sus entrenadores y la representaciĂłn simbĂłlica de estas relaciones. TambiĂ©n comprender
la intencionalidad de las relaciones homoafetivas que se intercambian entre algunos componentes del equipo directivo y(undefined
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