Connecting physical resonant amplitudes and lattice QCD

We present a determination of the isovector, $P$-wave $\pi\pi$ scattering phase shift obtained by extrapolating recent lattice QCD results from the Hadron Spectrum Collaboration using $m_\pi =236$ MeV. The finite volume spectra are described using extensions of L\"uscher's method to determine the infinite volume Unitarized Chiral Perturbation Theory scattering amplitude. We exploit the pion mass dependence of this effective theory to obtain the scattering amplitude at $m_\pi= 140$ MeV. The scattering phase shift is found to be in good agreement with experiment up to center of mass energies of 1.2 GeV. The analytic continuation of the scattering amplitude to the complex plane yields a $\rho$-resonance pole at $E_\rho= \left[755(2)(1)(^{20}_{02})-\frac{i}{2}\,129(3)(1)(^{7}_{1})\right]~{\rm MeV}$. The techniques presented illustrate a possible pathway towards connecting lattice QCD observables of few-body, strongly interacting systems to experimentally accessible quantities.Comment: 8 pages, 6 figures, equivalent to published version, added two appendices and a figur

Changing Patterns of Human Campylobacteriosis, England and Wales, 1990–2007

To explore hypotheses for age-related changes in the incidence of Campylobacter infections in England and Wales during 1990–2007, we analyzed electronic laboratory data. Disease incidence was reduced among children, and the greatest increase in risk was for those >60 years of age. Risk factors for campylobacteriosis in the elderly population should be identified

B2 and G2 Toda systems on compact surfaces: a variational approach

We consider the B2 and G2 Toda systems on compact surfaces. We attack the problem using variational techniques. We get existence and multiplicity of solutions under a topological assumption on the surface and some generic conditions on the parameters. We also extend some of the results to the case of general systems.Comment: 28 pages, accepted on Journal of Mathematical Physic

Ultraviolet observations of the X-ray photoionized wind of Cygnus X-1 during X-ray soft/high state

(Shortened) Ultraviolet observations of the black hole X-ray binary Cygnus X-1 were obtained using the STIS on HSTubble. We detect P Cygni line features show strong, broad absorption components when the X-ray source is behind the companion star and noticeably weaker absorption when the X-ray source is between us and the companion star. We fit the P Cygni profiles using the SEI method applied to a spherically symmetric stellar wind subject to X-ray photoionization from the black hole. The Si IV doublet provides the most reliable estimates of the parameters of the wind and X-ray illumination. The velocity $v$ increases with radius $r$ according to $v=v_\infty(1-r_\star/r)^\beta$, with$\beta\approx0.75$ and $v_\infty\approx1420$ km s$^{-1}$.The microturbulent velocity was $\approx160$ km s$^{-1}$. Our fit implies a ratio of X-ray luminosity to wind mass-loss rate of L$_{X,38}/\dot M_{-6} \approx 0.33$, measured at $\dot M_{-6}$ = 4.8. Our models determine parameters that may be used to estimate the accretion rate onto the black hole and independently predict the X-ray luminosity. Our predicted L$_x$ matches that determined by contemporaneous RXTE ASM remarkably well, but is a factor of 3 lower than the rate according to Bondi-Hoyle-Littleton spherical wind accretion. We suggest that some of the energy of accretion may go into powering a jet.Comment: 34 pages, 21 figures, 4 tables, accepted for publication in Ap

The Effect of Temperature on the Surface Tension of Sap of Thuja Plicata Heartwood

Capillary rise and drop volume methods were applied to the measurement of heartwood sap surface tension. Increase in sap temperature appeared to cause a substantial decrease in surface tension as measured by the former method. Since with the latter method surface tension values only decreased from 58.1 to 56.8 dyne/cm over the temperature range 25 to 80 C, it was concluded that changes in the contact angle of sap on glass were likely to have affected the results obtained by the capillary rise method. The absence of a substantial decrease in sap surface tension with increasing temperature is of considerable relevance to lumber drying

The Sloan Lens ACS Survey. IX. Colors, Lensing and Stellar Masses of Early-type Galaxies

We present the current photometric dataset for the Sloan Lens ACS (SLACS) Survey, including HST photometry from ACS, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade `A' (certain) lens systems, bringing the number of SLACS grade `A' lenses to 85; including 13 grade `B' (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade `A' systems have elliptical morphologies while ~10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for every system, making SLACS the largest homogeneous dataset of galaxy-scale lenses to date. We have developed a novel Bayesian stellar population analysis code to determine robust stellar masses with accurate error estimates. We apply this code to deep, high-resolution HST imaging and determine stellar masses with typical statistical errors of 0.1 dex; we find that these stellar masses are unbiased compared to estimates obtained using SDSS photometry, provided that informative priors are used. The stellar masses range from 10^10.5 to 10^11.8 M$_\odot$ and the typical stellar mass fraction within the Einstein radius is 0.4, assuming a Chabrier IMF. The ensemble properties of the SLACS lens galaxies, e.g. stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M* >~ 10^11 M$_\odot$, and are therefore an ideal dataset to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z ~ 0.5.Comment: 20 pages, 18 figures, 5 tables, published in Ap

The impact of relative position and returns on sacrifice and reciprocity: an experimental study using individual decisions

We present a comprehensive experimental design that makes it possible to characterize other-regarding preferences and their relationship to the decision maker’s relative position. Participants are faced with a large number of decisions involving variations in the trade-offs between own and other’s payoffs, as well as in other potentially important factors like the decision maker’s relative position. We find that: (1) choices are responsive to the cost of helping and hurting others; (2) The weight a decision maker places on others’ monetary payoffs depends on whether the decision maker is in an advantageous or disadvantageous relative position; and (3) We find no evidence of reciprocity of the type linked to menu-dependence. The results of a mixture-model estimation show considerable heterogeneity in subjects’ motivations and confirm the absence of reciprocal motives. Pure selfish behavior is the most frequently observed behavior. Among the subjects exhibiting social preferences, social-welfare maximization is the most frequent, followed by inequality-aversion and by competitiveness

Cancellation of Radiated Sound Fields by the Use of Multipole Secondary Sources

In this paper the cancellation of sound fields in the region exterior to a primary source by the use of a single, higher order, secondary source is discussed. The nature of the secondary source or sources required to achieve that cancellation, either globally or in particular regions, is a subject of current interest. It has recently been suggested that the sound radiation from coherent, finite size radiators may be represented as a superposition of monopole sound fields or alternatively as the sound field radiated by a single multipole. It has also been observed that the sound field radiated by a monopole source may be represented by an infinite order multipole source placed elsewhere. In the same way, multipole sources of finite order may be represented by displaced multipoles of higher order. In principle, it is thus possible to create a single multipole secondary source that could represent, and then if operated out of phase with respect to the primary source, cancel the sound field generated by an arbitrary coherent radiator. In this paper, the results of a theoretical and experimental study to determine the feasibility of such an approach are presented. Secondary sources of up to octupole order have been realized using loudspeakers and the farfield attenuation they may achieve has been established as a function of frequency, secondary source order and primary-secondary source separation distance. Excellent agreement between measurement and theoretical prediction has been obtained. It will be shown in particular that useful levels of low frequency global farfield attenuation may be obtained using secondary sources truncated at octupole order and positioned at a relatively large fraction of a wavelength from the primary source. In addition, it will be shown that the secondary multipole components’ strengths may be adjusted to achieve cancellation in specific angular sectors. It has thus been concluded that the approach suggested here may find applications in active control of low frequency exterior sound fields