Nonharmonic phonons in MgB_2 at elevated temperatures

Inelastic neutron scattering was used to measure phonon spectra in MgB_2 and Mg_(0.75)Al_(0.25)B_2 from 7 to 750 K to investigate anharmonicity and adiabatic electron-phonon coupling. First-principles calculations of phonons with a linear response method were performed at multiple unit cell volumes, and the Helmholtz free energy was minimized to obtain the lattice parameters and phonon dynamics at elevated temperature in the quasiharmonic approximation. Most of the temperature dependence of the phonon density of states could be understood with the quasiharmonic approximation, although there was also significant thermal broadening of the phonon spectra. In comparison to Mg_(0.75)Al_(0.25)B_2, in the energy range of 60 to 80 meV the experimental phonon spectra from MgB_2 showed a nonmonotonic change with temperature around 500 K. This may originate from a change with temperature of the adiabatic electron-phonon coupling

A microfabricated ion trap with integrated microwave circuitry

We describe the design, fabrication and testing of a surface-electrode ion trap, which incorporates microwave waveguides, resonators and coupling elements for the manipulation of trapped ion qubits using near-field microwaves. The trap is optimised to give a large microwave field gradient to allow state-dependent manipulation of the ions' motional degrees of freedom, the key to multiqubit entanglement. The microwave field near the centre of the trap is characterised by driving hyperfine transitions in a single laser-cooled 43Ca+ ion.Comment: 4 pages, 5 figure

Effects of X-rays on vascular function in transplanted tumours and normal tissues in the mouse.

The effects of X-radiation on the Nembutal-induced redistribution of the cardiac output in two types of transplanted mouse tumours and some normal mouse tissues have been investigated, using rubidium-86 and 125I-human serum albumin. Irradiation causes an increase in 86Rb uptake (relative blood perfusion) by the tumours of anaesthetized mice, but has little or no effect in non-anaesthetized mice. The increase is dose- and time-dependent. Tumour plasma space is not significantly affected by radiation and Nembutal. Muscle blood perfusion is severely decreased in anaesthetized mice and is not affected by radiation, at least within the time limits of the experiments. This means that radiation-induced functional vascular changes in normal and neoplastic tissues follow different time courses. On the basis of the present results, and of the results of other authors, it is argued that irradiation damages the vasculature of tumours in such a way that it becomes more sensitive to changes in systemic blood pressure

Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source

The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically focused neutron guide, high speed magnetic bearing choppers, and a massive array of ^3He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection

Moral cleansing as hypocrisy: When private acts of charity make you feel better than you deserve

What counts as hypocrisy? Current theorizing emphasizes that people see hypocrisy when an individual sends them “false signals” about his or her morality (Jordan, Sommers, Bloom, & Rand, 2017); indeed, the canonical hypocrite acts more virtuously in public than in private. An alternative theory posits that people see hypocrisy when an individual enjoys “undeserved moral benefits,” such as feeling more virtuous than his or her behavior merits, even when the individual has not sent false signals to others (Effron, O’Connor, Leroy, & Lucas, 2018). This theory predicts that acting less virtuously in public than in private can seem hypocritical by indicating that individuals have used good deeds to feel less guilty about their public sins than they should. Seven experiments (*N* = 3,468 representing 64 nationalities) supported this prediction. Participants read about a worker in a “sin industry” who secretly performed good deeds. When the individual’s public work (e.g., selling tobacco) was inconsistent with, versus unrelated to, the good deeds (e.g., anonymous donations to an anti-smoking cause vs. an anti-obesity cause), participants perceived him as more hypocritical, which in turn predicted less praise for his good deeds. Participants also inferred that the individual was using the inconsistent good deeds to cleanse his conscience for his public work, and such moral cleansing appeared hypocritical when it successfully alleviated his guilt. These results broaden and deepen understanding about how lay people conceptualize hypocrisy. Hypocrisy does not require appearing more virtuous than you are; it suffices to feel more virtuous than you deserve