1,631 research outputs found

    TB biomarkers, TB correlates and human challenge models: New tools for improving assessment of new TB vaccines

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    SummaryThe 4th Global Forum on TB Vaccines, convened in Shanghai, China, from 21 – 24 April 2015, brought together a wide and diverse community involved in tuberculosis vaccine research and development to discuss the current status of, and future directions for this critical effort. This paper summarizes the sessions on Biomarkers and Correlates, and Human Challenge Models. Summaries of all sessions from the 4th Global Forum are compiled in a special supplement of Tuberculosis. [August 2016, Vol 99, Supp S1, S1–S30]

    The Complexity of Graph-Based Reductions for Reachability in Markov Decision Processes

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    We study the never-worse relation (NWR) for Markov decision processes with an infinite-horizon reachability objective. A state q is never worse than a state p if the maximal probability of reaching the target set of states from p is at most the same value from q, regard- less of the probabilities labelling the transitions. Extremal-probability states, end components, and essential states are all special cases of the equivalence relation induced by the NWR. Using the NWR, states in the same equivalence class can be collapsed. Then, actions leading to sub- optimal states can be removed. We show the natural decision problem associated to computing the NWR is coNP-complete. Finally, we ex- tend a previously known incomplete polynomial-time iterative algorithm to under-approximate the NWR

    Maximum Edge-Disjoint Paths in kk-sums of Graphs

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    We consider the approximability of the maximum edge-disjoint paths problem (MEDP) in undirected graphs, and in particular, the integrality gap of the natural multicommodity flow based relaxation for it. The integrality gap is known to be Ω(n)\Omega(\sqrt{n}) even for planar graphs due to a simple topological obstruction and a major focus, following earlier work, has been understanding the gap if some constant congestion is allowed. In this context, it is natural to ask for which classes of graphs does a constant-factor constant-congestion property hold. It is easy to deduce that for given constant bounds on the approximation and congestion, the class of "nice" graphs is nor-closed. Is the converse true? Does every proper minor-closed family of graphs exhibit a constant factor, constant congestion bound relative to the LP relaxation? We conjecture that the answer is yes. One stumbling block has been that such bounds were not known for bounded treewidth graphs (or even treewidth 3). In this paper we give a polytime algorithm which takes a fractional routing solution in a graph of bounded treewidth and is able to integrally route a constant fraction of the LP solution's value. Note that we do not incur any edge congestion. Previously this was not known even for series parallel graphs which have treewidth 2. The algorithm is based on a more general argument that applies to kk-sums of graphs in some graph family, as long as the graph family has a constant factor, constant congestion bound. We then use this to show that such bounds hold for the class of kk-sums of bounded genus graphs

    Spectroscopy of 18^{18}Na: Bridging the two-proton radioactivity of 19^{19}Mg

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    The unbound nucleus 18^{18}Na, the intermediate nucleus in the two-proton radioactivity of 19^{19}Mg, was studied by the measurement of the resonant elastic scattering reaction 17^{17}Ne(p,17^{17}Ne)p performed at 4 A.MeV. Spectroscopic properties of the low-lying states were obtained in a R-matrix analysis of the excitation function. Using these new results, we show that the lifetime of the 19^{19}Mg radioactivity can be understood assuming a sequential emission of two protons via low energy tails of 18^{18}Na resonances

    Theory of Thermodynamic Magnetic Oscillations in Quasi-One-Dimensional Conductors

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    The second order correction to free energy due to the interaction between electrons is calculated for a quasi-one-dimensional conductor exposed to a magnetic field perpendicular to the chains. It is found that specific heat, magnetization and torque oscillate when the magnetic field is rotated in the plane perpendicular to the chains or when the magnitude of magnetic filed is changed. This new mechanism of thermodynamic magnetic oscillations in metals, which is not related to the presence of any closed electron orbits, is applied to explain behavior of the organic conductor (TMTSF)2_2ClO4_4.Comment: 11 pages + 5 figures (included

    Theoretical study of the two-proton halo candidate 17^{17}Ne including contributions from resonant continuum and pairing correlations

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    With the relativistic Coulomb wave function boundary condition, the energies, widths and wave functions of the single proton resonant orbitals for 17^{17}Ne are studied by the analytical continuation of the coupling constant (ACCC) approach within the framework of the relativistic mean field (RMF) theory. Pairing correlations and contributions from the single-particle resonant orbitals in the continuum are taken into consideration by the resonant Bardeen-Cooper-Schrieffer (BCS) approach, in which constant pairing strength is used. It can be seen that the fully self-consistent calculations with NL3 and NLSH effective interactions mostly agree with the latest experimental measurements, such as binding energies, matter radii, charge radii and densities. The energy of π\pi2s1/2_{1/2} orbital is slightly higher than that of π1d5/2\pi1d_{5/2} orbital, and the occupation probability of the (π(\pi2s1/2)2_{1/2})^2 orbital is about 20%, which are in accordance with the shell model calculation and three-body model estimation

    Charge Order with Structural Distortion in Organic Conductors: Comparison between \theta-(ET)2RbZn(SCN)4 and \alpha-(ET)2I3

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    Charge ordering with structural distortion in quasi-two-dimensional organic conductors \theta-(ET)2RbZn(SCN)4 (ET=BEDT-TTF) and \alpha-(ET)2I3 is investigated theoretically. By using the Hartree-Fock approximation for an extended Hubbard model which includes both on-site and intersite Coulomb interactions together with Peierls-type electron-lattice couplings, we examine the role of lattice degrees of freedom on charge order. It is found that the experimentally observed, horizontal charge order is stabilized by lattice distortion in both compounds. In particular, the lattice effect is crucial to the realization of the charge order in \theta-(ET)2RbZn(SCN)4, while the peculiar band structure whose symmetry is lower than that of \theta-(ET)2RbZn(SCN)4 in the metallic phase is also an important factor in \alpha-(ET)2I3 together with the lattice distortion. For \alpha-(ET)2I3, we obtain a phase transition from a charge-disproportionated metallic phase to the horizontal charge order with lattice modulations, which is consistent with the latest X-ray experimental result.Comment: 10 pages, 13 figures, to appear in J. Phys. Soc. Jpn. Vol. 77 (2008) No.

    Motivational Interviewing training for physiotherapy and occupational therapy students: Effect on confidence, knowledge and skills.

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    Copyright © 2019 The Authors. Objective: To examine the effectiveness of a three-day training programme on knowledge, confidence and fidelity to Motivational Interviewing (MI) delivery in an undergraduate occupational therapy and physiotherapy cohort (n = 25). Methods: Training outcomes were assessed pre-training, post-training and following a subsequent clinical placement. The Motivational Interviewing Knowledge and Attitudes Test (MIKAT) and an 8-item survey assessed knowledge, attitudes and confidence respectively. MI fidelity was evaluated by a simulated patient interview rated with the Motivational Interviewing Treatment Integrity scale (MITI). Analysis was by one-way repeated measures ANOVA. Results: Self-report measurements indicated increased confidence but no effect on knowledge or attitude. MITI analysis showed superior performance in all four global criteria and an increased frequency of MI adherent behaviours post-training. Positive changes were maintained following clinical placement. MITI summary scores indicated an improvement in question to reflection ratio in line with beginner competency. Conclusion(s): Participation in a three-day MI training programme significantly improved student confidence and MI skilfulness. Practice Implications: Where feasible, MI training should be embedded within the curriculum. Further research is needed elucidate the best practices to incorporate teaching this skill set within the curriculum in order to best prepare students to counsel clients in behaviour change in their applied settings.Health Education England North West Londo

    Positive Youth Development: Developing, Implementing, and Sustaining Music-Based Services for Emerging Adults Experiencing Homelessness

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    Research suggests that comprehensive services that consider the complex and interconnected needs of emerging adults experiencing homelessness may be more effective than interventions with a singular focus. There is little research that demonstrates how agencies that implement programs for individuals experiencing homelessness develop and sustain meaningful services for emerging adults, especially under conditions of increasing austerity. This study targets this gap in the literature by investigating how one transitional living program for emerging adults experiencing homelessness developed a music studio. Specifically, this study examines the factors and processes that were involved in developing, implementing, and sustaining the music studio. Findings suggest an ongoing organizational commitment to Positive Youth Development plays an important role

    High-Order Coupled Cluster Method Study of Frustrated and Unfrustrated Quantum Magnets in External Magnetic Fields

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    We apply the coupled cluster method (CCM) in order to study the ground-state properties of the (unfrustrated) square-lattice and (frustrated) triangular-lattice spin-half Heisenberg antiferromagnets in the presence of external magnetic fields. Here we determine and solve the basic CCM equations by using the localised approximation scheme commonly referred to as the `LSUBmm' approximation scheme and we carry out high-order calculations by using intensive computational methods. We calculate the ground-state energy, the uniform susceptibility, the total (lattice) magnetisation and the local (sublattice) magnetisations as a function of the magnetic field strength. Our results for the lattice magnetisation of the square-lattice case compare well to those results of QMC for all values of the applied external magnetic field. We find a value for magnetic susceptibility of χ=0.070\chi=0.070 for the square-lattice antiferromagnet, which is also in agreement with the results of other approximate methods (e.g., χ=0.0669\chi=0.0669 via QMC). Our estimate for the range of the extent of the (M/Ms=M/M_s=)13\frac 13 magnetisation plateau for the triangular-lattice antiferromagnet is 1.37<λ<2.151.37< \lambda < 2.15, which is in good agreement with results of spin-wave theory (1.248<λ<2.1451.248 < \lambda < 2.145) and exact diagonalisations (1.38<λ<2.161.38 < \lambda < 2.16). The CCM value for the in-plane magnetic susceptibility per site is χ=0.065\chi=0.065, which is below the result of the spin-wave theory (evaluated to order 1/S) of χSWT=0.0794\chi_{SWT}=0.0794.Comment: 30 pages, 13 figures, 1 Tabl
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