The effect of non-linear quantum electrodynamics on relativistic transparency and laser absorption in ultra-relativistic plasmas

With the aid of large-scale three-dimensional QED-PIC simulations, we describe a realistic experimental configuration to measure collective effects that couple strong field quantum electrodynamics to plasma kinetics. For two counter propagating lasers interacting with a foil at intensities exceeding $10^{22}$ Wcm$^{-2}$, a binary result occurs; when quantum effects are included, a foil that classically would effectively transmit the laser pulse becomes opaque. This is a dramatic change in plasma behavior, directly as a consequence of the coupling of radiation reaction and pair production to plasma dynamics

One qubit almost completely reveals the dynamics of two

From the time dependence of states of one of them, the dynamics of two interacting qubits is determined to be one of two possibilities that differ only by a change of signs of parameters in the Hamiltonian. The only exception is a simple particular case where several parameters in the Hamiltonian are zero and one of the remaining nonzero parameters has no effect on the time dependence of states of the one qubit. The mean values that describe the initial state of the other qubit and of the correlations between the two qubits also are generally determined to within a change of signs by the time dependence of states of the one qubit, but with many more exceptions. An example demonstrates all the results. Feedback in the equations of motion that allows time dependence in a subsystem to determine the dynamics of the larger system can occur in both classical and quantum mechanics. The role of quantum mechanics here is just to identify qubits as the simplest objects to consider and specify the form that equations of motion for two interacting qubits can take.Comment: 6 pages with new and updated materia

Crystallization, data collection and data processing of maltose-binding protein (MalE) from the phytopathogen Xanthomonas axonopodis pv. citri

Maltose-binding protein is the periplasmic component of the ABC transporter responsible for the uptake of maltose/maltodextrins. The Xanthomonas axonopodis pv. citri maltose-binding protein MalE has been crystallized at 293 Kusing the hanging-drop vapour-diffusion method. The crystal belonged to the primitive hexagonal space group P6_122, with unit-cell parameters a = 123.59, b = 123.59, c = 304.20 Å, and contained two molecules in the asymetric unit. It diffracted to 2.24 Å resolution

Spin observables and the determination of the parity of Θ+\Theta^+ in photoproduction reactions

Spin observables in the photoproduction of the $\Theta^+$ are explored for the purpose of determining the parity of the $\Theta^+$. Based on reflection symmetry in the scattering plane, we show that certain spin observables in the photoproduction of the $\Theta^+$ can be related directly to its parity. We also show that measurements of both the target nucleon asymmetry and the $\Theta^+$ polarization may be useful in determining the parity of $\Theta^+$ in a model-independent way. Furthermore, we show that no combination of spin observables involving only the polarization of the photon and/or nucleon in the initial state can determine the parity of $\Theta^+$ unambiguously.Comment: LaTeX, 11 pages, minor revisio

Opportunities for promoting physical activity in rural communities by understanding the interests and values of community members

Purpose. Physical activity (PA) has well-established health benefits, but most Americans do not meet national guidelines. In southeastern Missouri, trails have been developed to increase rates of PA. Although this has had success, broad-scale interventions will be needed to improve rates further. In this study, we surveyed residents of southeastern Missouri to identify ways to improve rates of PA. Methods. We conducted a telephone survey in 2015 of adults (n=524) from eight rural Missouri towns that had walking trails, regarding their activities and interests. Findings. Forty percent of respondents reported both walking and meeting PA recommendations, 29% reported walking but not meeting PA recommendations, and the remainder did not walk or did not answer. Respondents who used the trails were significantly more likely to meet PA recommendations (odds ratio = 2.7; 95% confidence interval = 1.7, 4.5). Certain values and interests that may encourage PA or draw people to trails were common. Conclusions. The group that walked but did not meet PA recommendations would be the ideal group to target for intervention, which could focus on their reported values and interests (e.g., personal relationships, being outdoors). Use of walking trails was associated with meeting PA recommendations