Non-linear Plasma Wake Growth of Electron Holes

An object's wake in a plasma with small Debye length that drifts \emph{across} the magnetic field is subject to electrostatic electron instabilities. Such situations include, for example, the moon in the solar wind wake and probes in magnetized laboratory plasmas. The instability drive mechanism can equivalently be considered drift down the potential-energy gradient or drift up the density-gradient. The gradients arise because the plasma wake has a region of depressed density and electrostatic potential into which ions are attracted along the field. The non-linear consequences of the instability are analysed in this paper. At physical ratios of electron to ion mass, neither linear nor quasilinear treatment can explain the observation of large-amplitude perturbations that disrupt the ion streams well before they become ion-ion unstable. We show here, however, that electron holes, once formed, continue to grow, driven by the drift mechanism, and if they remain in the wake may reach a maximum non-linearly stable size, beyond which their uncontrolled growth disrupts the ions. The hole growth calculations provide a quantitative prediction of hole profile and size evolution. Hole growth appears to explain the observations of recent particle-in-cell simulations

Coherent output of photons from coupled superconducting transmission line resonators controlled by charge qubits

We study the coherent control of microwave photons propagating in a superconducting waveguide consisting of coupled transmission line resonators, each of which is connected to a tunable charge qubit. While these coupled line resonators form an artificial photonic crystal with an engineered photonic band structure, the charge qubits collectively behave as spin waves in the low excitation limit, which modify the band-gap structure to slow and stop the microwave propagation. The conceptual exploration here suggests an electromagnetically controlled quantum device based on the on-chip circuit QED for the coherent manipulation of photons, such as the dynamic creation of laser-like output from the waveguide by pumping the artificial atoms for population inversion.Comment: 8 pages, 3 figure

Money, moral transgressions, and blame

Two experiments tested participants' attributions for others' immoral behaviors when conducted for more versus less money. We hypothesized and found that observers would blame wrongdoers more when seeing a transgression enacted for little rather than a lot of money, and that this would be evident in observers' hand-washing behavior. Experiment 1 used a cognitive dissonance paradigm. Participants (N = 160) observed a confederate lie in exchange for either a relatively large or a small monetary payment. Participants blamed the liar more in the small (versus large) money condition. Participants (N = 184) in Experiment 2 saw images of someone knocking over another to obtain a small, medium, or large monetary sum. In the small (versus large) money condition, participants blamed the perpetrator (money) more. Hence, participants assigned less blame to moral wrong-doers, if the latter enacted their deed to obtain relatively large sums of money. Small amounts of money accentuate the immorality of others' transgressions

Public vs private administration of rural health insurance schemes: a comparative study in Zhejiang of China.

: Since 2003, China has experimented in some of the country's counties with the private administration of the New Cooperative Medical Scheme (NCMS), a publicly subsidized health insurance scheme for rural populations. Our study compared the effectiveness and efficiency of private vs public administration in four counties in one of China's most affluent provinces in the initial stage of the NCMS's implementation. The study was undertaken in Ningbo city of Zhejiang province. Out of 10 counties in Ningbo, two counties with private administration for the NCMS (Beilun and Ninghai) were compared with two others counties with public administration (Zhenhai and Fenghua), using the following indicators: (1) proportion of enrollees who were compensated for inpatient care; (2) average reimbursement-expense ratio per episode of inpatient care; (3) overall administration cost; (4) enrollee satisfaction. Data from 2004 to 2006 were collected from the local health authorities, hospitals and the contracted insurance companies, supplemented by a randomized household questionnaire survey covering 176 households and 479 household members. In our sample counties, private administration of the NCMS neither reduced transaction costs, nor improved the benefits of enrollees. Enrollees covered by the publicly administered NCMS were more likely to be satisfied with the insurance scheme than those covered by the privately administered NCMS. Experience in the selected counties suggests that private administration of the NCMS did not deliver the hoped-for results. We conclude that caution needs to be exercised in extending private administration of the NCMS

Elastic Wave Scattering and Dynamic Stress Concentrations in Stretching Thick Plates with Two Cutouts by Using the Refined Dynamic Theory

Based on the refined dynamic equation of stretching plates, the elastic tension–compression wave scattering and dynamic stress concentrations in the thick plate with two cutouts are studied. In view of the problem that the shear stress is automatically satisfied under the free boundary condition, the generalized stress of the first-order vanishing moment of shear stress is considered. The numerical results indicate that, as the cutout is thick, the maximum value of the dynamic stress factor obtained using the refined dynamic theory is 19% higher than that from the solution of plane stress problems of elastic dynamics