The B_s and D_s decay constants in 3 flavor lattice QCD

Capitalizing on recent advances in lattice QCD, we present a calculation of the leptonic decay constants f_{B_s} and f_{D_s} that includes effects of one strange sea quark and two light sea quarks. The discretization errors of improved staggered fermion actions are small enough to simulate with 3 dynamical flavors on lattices with spacings around 0.1 fm using present computer resources. By shedding the quenched approximation and the associated lattice scale ambiguity, lattice QCD greatly increases its predictive power. NRQCD is used to simulate heavy quarks with masses between 1.5 m_c and m_b. We arrive at the following results: f_{B_s} = 260 \pm 7 \pm 26 \pm 8 \pm 5 MeV and f_{D_s} = 290 \pm 20 \pm 29 \pm 29 \pm 6 MeV. The first quoted error is the statistical uncertainty, and the rest estimate the sizes of higher order terms neglected in this calculation. All of these uncertainties are systematically improvable by including another order in the weak coupling expansion, the nonrelativistic expansion, or the Symanzik improvement program.Comment: 4 page

D_s spectrum and leptonic decays with Fermilab heavy quarks and improved staggered light quarks

We present preliminary results for the D_s meson spectrum and decay constants in unquenched lattice QCD. Simulations are carried out with 2+1 dynamical quarks using gauge configurations generated by the MILC collaboration. We use the ``asqtad'' a^2 improved staggered action for the light quarks, and the clover heavy quark action with the Fermilab interpretation. We compare our spectrum results with the newly discovered 0+ and 1+ states in the D_s system.Comment: 3pp. Presented at 21st International Symposium on Lattice Field Theory (LATTICE 2003), Tsukuba, Ibaraki, Japan, 15-19 Jul 200

Measuring the Quality of Postgraduate Physician Assistant Fellowship/Residency Programs with a Surgical Focus

Introduction Postgraduate programs for PAs provide formal postgraduate training for clinical specialty areas. These programs are intended to provide intense specialty training in various fields, as well as to standardize education beyond the entry level. The purpose of this descriptive study was to determine if there are consistent trends or clear differences in program length, approach to training, validation of learning, and accreditation through the Accreditation Review Commission on Education for the Physician Assistant (ARC-PA) for postgraduate programs with a surgical focus in the United States. Methods This study is a non-experimental and descriptive research design. Program directors were mailed a survey consisting of questions about program information, prerequisites, curriculum, training, evaluation, and perspective of graduates after completion of program. Results Of the 29 program directors who were mailed a survey, 62% responded with completed surveys (n=18). 38% of respondents (n=11) stated the annual salary ranged from $40,000 to$60,000. Five programs were accredited by the ARC-PA and four programs were actively seeking accreditation. The majority of program directors believed the attitude of the medical community is higher towards PAs who complete a postgraduate education program. Conclusion As postgraduate programs increase in popularity, it is important to evaluate the standardization of the programs nationally. Papers like this will help drive a consistent approach to PA fellowship development and evolution. As healthcare evolves, there is a need to develop highly specialized physician assistants and place a premium on retaining them within the healthcare systems. Obtaining information on standard practices across postgraduate PA programs helps determine what requirements should be upheld nationally

Heavy-Light Mesons with Quenched Lattice NRQCD: Results on Decay Constants

We present a quenched lattice calculation of heavy-light meson decay constants, using non-relativistic (NRQCD) heavy quarks in the mass region of the $b$ quark and heavier, and clover-improved light quarks. The NRQCD Hamiltonian and the heavy-light current include the corrections at first order in the expansion in the inverse heavy quark mass. We study the dependence of the decay constants on the heavy meson mass $M$, for light quarks with the tree level ($c_{SW}$ = 1), as well as the tadpole improved clover coefficient. We compare decay constants from NRQCD with results from clover ($c_{SW}=1$) heavy quarks. Having calculated the current renormalisation constant $Z_A$ in one-loop perturbation theory, we demonstrate how the heavy mass dependence of the pseudoscalar decay constants changes after renormalisation. For the first time, we quote a result for $f_B$ from NRQCD including the full one-loop matching factors at $O(\alpha/M)$.Comment: 45 pages, latex, 24 postscript figure

Structure and activity of the Streptococcus pyogenes family GH1 6-phospho β-glycosidase, Spy1599

The group A streptococcus Streptococcus pyogenes is the causative agent of a wide spectrum of invasive infections, including necrotizing fasciitis, scarlet fever and toxic shock syndrome. In the context of its carbohydrate chemistry, it is interesting that S. pyogenes (in this work strain M1 GAS SF370) displays a spectrum of oligosaccharide-processing enzymes that are located in close proximity on the genome but that the in vivo function of these proteins remains unknown. These proteins include different sugar transporters (SPy1593 and SPy1595), both GH125 -1,6- and GH38 -1,3-mannosidases (SPy1603 and SPy1604), a GH84 -hexosaminidase (SPy1600) and a putative GH2 -galactosidase (SPy1586), as well as SPy1599, a family GH1 `putative -glucosidase'. Here, the solution of the three-dimensional structure of SPy1599 in a number of crystal forms complicated by unusual crystallographic twinning is reported. The structure is a classical (/)8-barrel, consistent with CAZy family GH1 and other members of the GH-A clan. SPy1599 has been annotated in sequence depositions as a -glucosidase (EC 3.2.1.21), but no such activity could be found; instead, three-dimensional structural overlaps with other enzymes of known function suggested that SPy1599 contains a phosphate-binding pocket in the active site and has possible 6-phospho--glycosidase activity. Subsequent kinetic analysis indeed showed that SPy1599 has 6-phospho--glucosidase (EC 3.2.1.86) activity. These data suggest that SPy1599 is involved in the intracellular degradation of 6-phosphoglycosides, which are likely to originate from import through one of the organism's many phosphoenolpyruvate phosphotransfer systems (PEP-PTSs)

Controlling the quantum dynamics of a mesoscopic spin bath in diamond

Understanding and mitigating decoherence is a key challenge for quantum science and technology. The main source of decoherence for solid-state spin systems is the uncontrolled spin bath environment. Here, we demonstrate quantum control of a mesoscopic spin bath in diamond at room temperature that is composed of electron spins of substitutional nitrogen impurities. The resulting spin bath dynamics are probed using a single nitrogen-vacancy (NV) centre electron spin as a magnetic field sensor. We exploit the spin bath control to dynamically suppress dephasing of the NV spin by the spin bath. Furthermore, by combining spin bath control with dynamical decoupling, we directly measure the coherence and temporal correlations of different groups of bath spins. These results uncover a new arena for fundamental studies on decoherence and enable novel avenues for spin-based magnetometry and quantum information processing

You can lead a horse to water . . . what Self-Determination Theory can contribute to our understanding of clinical policy implementation

There has been increasing reliance on policy directives as instruments for shaping clinical practice in health care, despite it being widely recognized that there is a significant translation gap between clinical policy and its implementation. Self- Determination Theory, a widely researched and empirically validated theory of human needs’ fulfilment and motivation, offers a potentially valuable theoretical framework for understanding not only why the current policy environment has not led to the anticipated improvement in the quality and safety of clinical care but, importantly, also provides guidance about how organizations can create an environment that can nurture behavioural change in the workforce. We describe an alternative approach to clinical policy-making underpinned by Self-Determination Theory, which we believe has broad application for the science of clinical implementation theory

Comparison Studies of Finite Momentum Correlators on Anisotropic and Isotropic Lattices

We study hadronic two- and three-point correlators relevant for heavy to light pseudoscalar meson semi-leptonic decays, using Symanzik improved glue, D234 light quark and NRQCD heavy quark actions. Detailed comparisons are made between simulations on anisotropic and isotropic lattices involving finite momentum hadrons. We find evidence that having an anisotropy helps in extracting better signals at higher momenta. Initial results for the form factors f_+(q^2) and f_0(q^2) are presented with tree-level matching of the lattice heavy-light currents.Comment: 43 pages with 50 postscript figure