The Orbital Ephemeris and X-Ray Light Curve of Cyg X-3

The orbital dynamics of Cyg X-3 are a key to understanding this enigmatic X-ray binary. Recent observations by the RXTE ASM and the OSSE instrument on GRO enable us to extend the baseline of arrival time measurements and test earlier models of orbital period evolution. We derive new quadratic and cubic ephemerides from the soft X-ray data (including ASM). We find a significant shift between the predicted soft X-ray phase and the light curve phase measured by OSSE from ~44 to 130 keV. Some of the apparent phase shift may be caused by a difference in light curve shape.Comment: 5 pages, 2 figures, LaTeX (aipproc); to be published in the Proceedings of the 4th Compton Symposiu

Modal Analysis of a Two-Parachute System

The Orion capsule is designed to land under a nominal configuration of three main parachutes; however, the system is required to be fault tolerant and land successfully if one of the main parachutes fails to open. The Capsule Parachute Assembly System (CPAS) Team performed a series of drop tests in order to characterize the performance of the system with two main parachutes. During the series of drop tests, several distinct dynamical modes were observed. The most consequential of these is the pendulum mode. Three other modes are benign: flyout (scissors), maypole, and breathing. The actual multi-body system is nonlinear, flexible, and possesses significant cross-coupling. Rather than perform analysis of this highly complex system directly, we conduct analysis of each dynamical mode observed during flight, based on first principles. This approach is analogous to traditional aircraft flight dynamics analysis in which the full nonlinear behavior of the airframe is decomposed into longitudinal dynamics (phugoid and short-period modes) and lateral dynamics (spiral, roll-subsidence, and dutch-roll modes). This analysis is intended to supplement multi-body nonlinear simulations in order to provide further insight into the system

Église et société au Moyen-Âge

On ne peut comprendre le Moyen Âge sans comprendre le rôle de l’Église.De la chute de l’empire romain d’occident et la conversion des royaumes barbares aux débuts de la Renaissance, l’Europe et la chrétienté se confondent.Cet ouvrage permet de comprendre le rôle de l’Église dans l’évolution de la société médiévale. Un rôle culturel et politique mais aussi économique et juridique. C’est l’Église qui en grande partie forge cette société qui n’est pas sans réagir, parfois violement. La fin du Moyen âge marque un retour des crises internes qui annoncent la réforme.POINTS FORTS- L’ouvrage est parfaitement à jour des recherches les plus récentes.- Les relations entre l’Église et la société sont analysées de façon exhaustives et synthétiquesSOMMAIREPartie 1 : Essor et diversité du christianisme en occident (vers 400-vers 750)1. Héritage de l\u27antiquité tardive2. Les églises des royaumes occidentaux3. Le monde des moines : unité ou diversité ?4. L\u27encadrement des fidèlesPartie 2 : Une église universelle et homogène : le rêve impossible ?(vers 750-vers 1050)1. L\u27ordre carolingien et son rayonnement2. Les conflits d\u27intérêts au sein de l\u27église carolingienne3. Rénovation imperii et expansion de la chrétienté (vers 920-vers 1020)4. Vers une institutionnaliasation de l\u27ecclesia (vers 1020-vers 1050)Partie 3 : Apogée de la papauté et christianisation de la société (vers 1050-vers 1274)1. L\u27affirmation de la papauté (vers 1050 – vers 1190)2. Vigueur de l\u27institution et vitalité de la vie religieuse au XIIe siècle3. Le "beau XIIIe siècle" de l\u27Eglise : réalités et limites4. La christianisation de la société : résistances et contestationsPartie 4 : Le temps des crises et des réformes (vers 1274-vers 1517)5. De l\u27apogée de la papauté à la première crise des institutions6. Schismes, conciles et essor des églises nationales (1378- début XVIe s.)7. La réforme du clergé : succès et limites8. Réforme et vie religieuse des laïcsLES AUTEURS- Anne-Marie Helvétius est professeur d’histoire médiévale à l’université Paris-VIII-Vincennes-Saint-Denis.- Jean-Michel Matz est professeur d’histoire médiévale à l’université d’Anger.PUBLIC CIBLE- Étudiants en histoire en Licence et en Master

Linear Analysis of a Two-Parachute System Undergoing Pendulum Motion

Motion resembling that of a pendulum undergoing large-amplitude oscillation was ob- served during a series of flight tests of an unoccupied Orion Capsule Parachute Assembly System (CPAS) drop-test vehicle. Large excursions away from vertical by the capsule could cause it to strike the ground or ocean at a large angle with respect to vertical, with an undesirable attitude with respect to heading, or with a large horizontal or vertical speed. These conditions are to be avoided because they would endanger the occupants of the capsule in an actual mission. Pendulum motion is intimately related to a parachutes aerodynamic normal force coefficient, which is a nonlinear function of angle of attack. An analytical investigation of the dynamics of pendulum motion is undertaken with the aid of a simplified model of the physical system and the assumption that the normal force coefficient is a linear function of angle of attack in the neighborhood of a value corresponding to stable equilibrium. The analysis leads to a simple relationship for the location of a pivot point, which provides insights that are consistent with previous studies

Compton Echoes from Gamma-ray Bursts

Recent observations of gamma-ray bursts (GRBs) have provided growing evidence for collimated outflows and emission, and strengthened the connection between GRBs and supernovae. If massive stars are the progenitors of GRBs, the hard photon pulse will propagate in the pre-burst, dense environment. Circumstellar material will Compton scatter the prompt GRB radiation and give rise to a reflection echo. We calculate luminosities, spectra, and light curves of such Compton echoes in a variety of emission geometries and ambient gas distributions, and show that the delayed hard X-ray flash from a pulse propagating into a red supergiant wind could be detectable by Swift out to z~0.2. Independently of the gamma-ray spectrum of the prompt burst, reflection echoes will typically show a high-energy cutoff between m_ec^2/2 and m_ec^2 because of Compton downscattering. At fixed burst energy per steradian, the luminosity of the reflected echo is proportional to the beaming solid angle, Omega_b, of the prompt pulse, while the number of bright echoes detectable in the sky above a fixed limiting flux increases as Omega_b^{1/2}, i.e. it is smaller in the case of more collimated jets. The lack of an X-ray echo at one month delay from the explosion poses severe constraints on the possible existence of a lateral GRB jet in SN 1987A. The late r-band afterglow observed in GRB990123 is fainter than the optical echo expected in a dense red supergiant environment from a isotropic prompt optical flash. Significant MeV delayed emission may be produced through the bulk Compton (or Compton drag) effect resulting from the interaction of the decelerating fireball with the scattered X-ray radiation.Comment: LaTeX, 18 pages, 4 figures, revised version accepted for publication in the Ap

OSSE spectral analysis techniques

Analysis of the spectra from the Oriented Scintillation Spectrometer Experiment (OSSE) is complicated because of the typically low signal to noise (approx. 0.1 percent) and the large background variability. The OSSE instrument was designed to address these difficulties by periodically offset-pointing the detectors from the source to perform background measurements. These background measurements are used to estimate the background during each of the source observations. The resulting background-subtracted spectra can then be accumulated and fitted for spectral lines and/or continua. Data selection based on various environmental parameters can be performed at various stages during the analysis procedure. In order to achieve the instrument's statistical sensitivity, however, it will be necessary for investigators to develop a detailed understanding of the instrument operation, data collection, and the background spectrum and its variability. A brief description of the major steps in the OSSE spectral analysis process is described, including a discussion of the OSSE background spectrum and examples of several observational strategies

Mutual Zonated Interactions of Wnt and Hh Signaling Are Orchestrating the Metabolism of the Adult Liver in Mice and Human

The Hedgehog (Hh) and Wnt/β-Catenin (Wnt) cascades are morphogen pathways whose pronounced influence on adult liver metabolism has been identified in recent years. How both pathways communicate and control liver metabolic functions are largely unknown. Detecting core components of Wnt and Hh signaling and mathematical modeling showed that both pathways in healthy liver act largely complementary to each other in the pericentral (Wnt) and the periportal zone (Hh) and communicate mainly by mutual repression. The Wnt/Hh module inversely controls the spatiotemporal operation of various liver metabolic pathways, as revealed by transcriptome, proteome, and metabolome analyses. Shifting the balance to Wnt (activation) or Hh (inhibition) causes pericentralization and periportalization of liver functions, respectively. Thus, homeostasis of the Wnt/Hh module is essential for maintaining proper liver metabolism and to avoid the development of certain metabolic diseases. With caution due to minor species-specific differences, these conclusions may hold for human liver as well

Multipliers for p-Bessel sequences in Banach spaces

Multipliers have been recently introduced as operators for Bessel sequences and frames in Hilbert spaces. These operators are defined by a fixed multiplication pattern (the symbol) which is inserted between the analysis and synthesis operators. In this paper, we will generalize the concept of Bessel multipliers for p-Bessel and p-Riesz sequences in Banach spaces. It will be shown that bounded symbols lead to bounded operators. Symbols converging to zero induce compact operators. Furthermore, we will give sufficient conditions for multipliers to be nuclear operators. Finally, we will show the continuous dependency of the multipliers on their parameters.Comment: 17 page