XMM-Newton observation of the double pulsar system J0737-3039

We report on a 50 ksec XMM-Newton observation of the double pulsar system J0737-3039 performed on April 2004. We present results of the spectral analysis of these data combined with the much shorter Chandra pointing performed on January 2004. Black body emission with effective temperature of 0.20^{+0.02}_{-0.02} keV (90% confidence level) and emission radius 75^{+30}_{-9} m for a distance of 0.5 kpc (implying a 0.5-10 keV luminosity \~6x10^{29} erg/s) is a viable interpretation, calling for a stream of particles accelerated in the magnetosphere of PSR J0737-3039A and depositing their kinetic energy in the magnetic polar cap of PSR J0737-3039A or of the companion PSR J0737-3039B. A single power-law emission model implies a very steep photon index Gamma=4.2^{+2.1}_{-1.2} and a suspiciously high hydrogen column density, whereas a photon index Gamma=2 does not provide an adequate description of the XMM-Newton and Chandra data. A two component model (a black body plus a power-law with Gamma=2) is statistically acceptable, but the additional power-law component is not required by the data.Comment: Accepted for publication on ApJ

HST Proper Motion confirms the optical identification of the nearby pulsar PSR 1929+10

We report on the proper motion measurement of the proposed optical counterpart of the X-ray/radio pulsar PSR 1929+10. Using images obtained with the HST/STIS (average epoch 2001.73) we computed a yearly displacement of +97 +/- 1 mas yr^{-1} in RA and +46 +/- 1 mas yr^{-1} in Dec since the epoch (1994.52) of the original HST/FOC detection. Both the magnitude and direction of the optical proper motion components are found to be fully consistent with the most recent VLBA radio measurements. This result provides an unambiguous confirmation of the pulsar optical identification. In addition, we have used the combined STIS/FOC datasets to derive information on the pulsar spectrum, which seems characterized by a power law component, apparently unrelated to the X-ray emission.Comment: 12 pages, 3 figures, submitted to ApJ Letter

X-Rays from the Nearby Solitary Millisecond Pulsar PSR J0030+0451 - the Final ROSAT Observations

We report on X-ray observations of the solitary 4.8 ms pulsar PSR J0030+0451. The pulsar was one of the last targets observed in DEC-98 by the ROSAT PSPC. X-ray pulses are detected on a $4.5\sigma$ level and make the source the $11^{th}$ millisecond pulsar detected in the X-ray domain. The pulsed fraction is found to be $69\pm18$. The X-ray pulse profile is characterized by two narrow peaks which match the gross pulse profile observed at 1.4 GHz. Assuming a Crab-like spectrum the X-ray flux is in the range $f_x= 2-3\times 10^{-13}$ erg s$^{-1}$ cm$^{-2}$ ($0.1-2.4$ keV), implying an X-ray efficiency of $L_x/\dot{E}\sim 0.5-5 \times 10^{-3} (d/0.23 {kpc})^2$.Comment: Accepted for publication in Ap

It’s Not What They Do, It’s How They Do It: Athlete Experiences of Great Coaching

Throughout the history of sport, a select number of individuals have emerged from their peers as superior coaches. We have come to know these individuals as the coaching greats: Vince Lombardi of the Green Bay Packers, Pat Summitt of the Tennessee Lady Volunteers, and John Wooden of the UCLA Bruins to name a few. The context of sport lends itself to the study of coaching greatness; however, no studies have directly explored this phenomenon. More often than not, society identifies coaches as “great” based on two criteria: win/loss records and public attention that is garnered through the media. This narrow definition limits the study of coaching greatness in two ways. First, the media focuses its coverage on high visibility sports and on coaches that work at higher levels of competition. Second, a winning record may not necessarily mean that a coach is great. As a result, we cannot rely on external resources (i.e., win/loss records and the media) to define greatness or to gain a thorough understanding of the factors that underlie great coaching. To truly explore this phenomenon, we must examine coaches from a variety of sports and competitive levels. If coaches are not winning championships or getting media attention, perhaps the only way to accurately determine their greatness is through the athletes that play for them. Therefore, the primary purpose of this study was to explore athlete experiences of great coaching. This was achieved by conducting a total of 18 in-depth phenomenological interviews with elite level athletes (9 female; 9 male) representing a variety of sports (i.e., baseball, basketball, football, soccer, softball, volleyball, and water polo). Participants ranged in age from 22 to 42 years. All interview transcripts were typed verbatim. Analyses of the transcripts revealed a total of 1,553 meaning units that were further grouped into sub-themes and general themes. This led to the development of a final thematic structure revealing six major dimensions that characterized these athletes’ experiences of great coaching: Coach Attributes, The Environment, Relationships, The System, Coaching Actions, and Influences

Effects of Anharmonicity on Vibrational Frequencies and Molar Absorptivities of Triplet-HON

The reaction between NO and atomic hydrogen to form HNO is one that has been studied both experimentally and theoretically due to the observation of HNO in interstellar matter, as well as HNO\u27s role as an intermediate product in some atmospheric reactions.[5] However, this reaction can also produce the HON molecule when performed in solid argon or para-hydrogen matrix environments at extremely low temperatures (10K and below 5K, respectively). [15, 20] Surprisingly, the HNO and HON products are formed at comparable rates in the para-hydrogen matrix, even though the reaction to form HNO has no energy barrier whilst the formation of HON must surpass a 12 kcal=mol barrier.[20, 5] The molar absorptivities of these two molecules are required to thoroughly study the kinetics of the H + NO reaction occurring within the matrix; since the IR spectrum is taken in situ, these values must be obtained computationally.The Double Harmonic Approximation (DHA) is a common method for calculating the molar absorptivities of a molecule; however, the DHA does not consider anharmonicity or coupling between vibrational levels. We propose both of these additions as important contributors to the molar absorptivities of HON due to the highly anharmonic character of its O-H vibrational mode, and therefore applied Vibrational Second-Order Perturbation Theory (VPT2). Unfortunately, while the VPT2 method provided better models of the potential energies than the DHA, the dipole moment polynomials were less accurate when compared to the ab initio data. Application of the linear variational method instead of VPT2 allowed us to control over whether or not coupling was included in the system, as well as the number of anharmonicity terms added (degree of polynomial), and we found a 10th order polynomial with a linear combination of the harmonic wavefunctions nine lowest energy levels was necessary to best model a single vibrational mode. The combinations of harmonic wavefunctions from each vibrational mode required when modeling the entire system is still unclear, but the inclusion of coupling between the modes has a significant effect on the calculated anharmonic frequencies and should be taken into account in any future analysis

Job Insecurity and Youth Emancipation: A Theoretical Approach

In this paper, we propose a theoretical model to study the effect of income insecurity of parents and offspring on the child's residential choice. Parents are partially altruistic toward their children and will provide financial help to an independent child when her income is low relative to the parents'. We show that first-order stochastic dominance (FOSD) shifts in the distribution of the child's future income (or her parents') will have ambiguous effects on the child's residential choice. The analysis identifies altruism as the source of ambiguity in the results. If parents are selfish or the joint income distribution of parents and child places no mass on the region where transfers are provided, a FOSD shift in the distribution of the child's (parents') future income will reduce (raise) the child's current income threshold for independenceAltruism; Emancipation; Job security; Option value

Job Insecurity and Children's Emancipation

The age at which children leave the parental home differs considerably across countries. We present a theoretical model predicting that higher job security of parents and lower job security of children may delay emancipation. We then provide aggregate evidence which supports this hypothesis for 12 European countries. We also give microeconometric evidence for Italy, the single country for which we have access to household-specific information on job security and coresidence. It is a very interesting case to study since, in the late 1990s, approximately 75 per cent of young Italians aged 18 to 35 were living at home and they had only a 4 per cent probability of emancipation in the subsequent 3 years. We show that this probability would have increased by 4 to 10 percentage points if their fathers had gone from having a fully secure job to becoming unemployed for sure.emancipation, job security, option value

Three-graviton scattering and recoil effects in M-atrix theory

We study the scattering of three gravitons in M-atrix theory at finite N. With a specific choice of the background we obtain the complete result up to two loops. The contributions from three-body forces agree with the ones presented in recent papers. We extend the calculation and evaluate the two-body exchanges as well. Such terms, somewhat difficult to isolate and compute, had been neglected so far in the existing literature. We show that the result we have obtained from M-atrix theory precisely matches the result from one-particle reducible tree diagrams in eleven-dimensional supergravity .Comment: corrected reference to the second paper in ref [6] in which recoil effects were considered and comparative comments added. latex, 22 page