Shuttle payload S-band communications system

The Shuttle payload S-band communications system design, operational capabilities, and performance are described in detail. System design requirements, overall system and configuration and operation, and laboratory/flight test results are presented. Payload communications requirements development is discussed in terms of evolvement of requirements as well as the resulting technical challenges encountered in meeting the initial requirements. Initial design approaches are described along with cost-saving initiatives that subsequently had to be made. The resulting system implementation that was finally adopted is presented along with a functional description of the system operation. A description of system test results, problems encountered, how the problems were solved, and the system flight experience to date is presented. Finally, a summary of the advancements made and the lessons learned is discussed

Physical mechanisms of interface-mediated intervalley coupling in Si

The conduction band degeneracy in Si is detrimental to quantum computing based on spin qubits, for which a nondegenerate ground orbital state is desirable. This degeneracy is lifted at an interface with an insulator as the spatially abrupt change in the conduction band minimum leads to intervalley scattering. We present a theoretical study of the interface-induced valley splitting in Si that provides simple criteria for optimal fabrication parameters to maximize this splitting. Our work emphasizes the relevance of different interface-related properties to the valley splitting.Comment: 4 pages, revised versio

Preliminary catalog of pictures taken on the lunar surface during the Apollo 15 mission

Catalog of all pictures taken from lunar module or lunar surface during Apollo 15 missio

First-principle study of excitonic self-trapping in diamond

We present a first-principles study of excitonic self-trapping in diamond. Our calculation provides evidence for self-trapping of the 1s core exciton and gives a coherent interpretation of recent experimental X-ray absorption and emission data. Self-trapping does not occur in the case of a single valence exciton. We predict, however, that self-trapping should occur in the case of a valence biexciton. This process is accompanied by a large local relaxation of the lattice which could be observed experimentally.Comment: 12 pages, RevTex file, 3 Postscript figure

Temperature effects on dislocation core energies in silicon and germanium

Temperature effects on the energetics of the 90-degree partial dislocation in silicon and germanium are investigated, using non-equilibrium methods to estimate free energies, coupled with Monte Carlo simulations. Atomic interactions are described by Tersoff and EDIP interatomic potentials. Our results indicate that the vibrational entropy has the effect of increasing the difference in free energy between the two possible reconstructions of the 90-degree partial, namely, the single-period and the double-period geometries. This effect further increases the energetic stability of the double-period reconstruction at high temperatures. The results also indicate that anharmonic effects may play an important role in determining the structural properties of these defects in the high-temperature regime.Comment: 8 pages in two-column physical-review format with six figure

Empathy: a review of the concept

The inconsistent definition of empathy has had a negative impact on both research and practice. The aim of this article is to review and critically appraise a range of definitions of empathy and, through considered analysis, to develop a new conceptualisation. From the examination of 43 discrete definitions, 8 themes relating to the nature of empathy emerged: “distinguishing empathy from other concepts”; “cognitive or affective?”; “congruent or incongruent?”; “subject to other stimuli?”; “self/other distinction or merging?”; “trait or state influences?”; “has a behavioural outcome?”; and “automatic or controlled?” The relevance and validity of each theme is assessed and a new conceptualisation of empathy is offered. The benefits of employing a more consistent and complete definition of empathy are discussed

Pines’ demon observed as a 3D acoustic plasmon in Sr₂RuO₄

Sr2RuO4での「パインズの悪魔」の観測 67年前に予言された金属の奇妙な振る舞いの発見. 京都大学プレスリリース. 2023-08-10.Speak of the Demon: Discovery of strange behavior of new plasmons predicted in the 50s. 京都大学プレスリリース. 2023-09-25.The characteristic excitation of a metal is its plasmon, which is a quantized collective oscillation of its electron density. In 1956, David Pines predicted that a distinct type of plasmon, dubbed a ‘demon’, could exist in three-dimensional (3D) metals containing more than one species of charge carrier. Consisting of out-of-phase movement of electrons in different bands, demons are acoustic, electrically neutral and do not couple to light, so have never been detected in an equilibrium, 3D metal. Nevertheless, demons are believed to be critical for diverse phenomena including phase transitions in mixed-valence semimetals, optical properties of metal nanoparticles, soundarons in Weyl semimetals and high-temperature superconductivity in, for example, metal hydrides. Here, we present evidence for a demon in Sr₂RuO₄ from momentum-resolved electron energy-loss spectroscopy. Formed of electrons in the β and γ bands, the demon is gapless with critical momentum qc = 0.08 reciprocal lattice units and room-temperature velocity v = (1.065 ± 0.12) × 10⁵ m s⁻¹ that undergoes a 31% renormalization upon cooling to 30 K because of coupling to the particle–hole continuum. The momentum dependence of the intensity of the demon confirms its neutral character. Our study confirms a 67-year old prediction and indicates that demons may be a pervasive feature of multiband metals

Posttraumatic growth as positive personality change: evidence, controversies and future directions

This target article focuses on the construct of post-traumatic growth—positive psychological change experienced as a result of the struggle with highly challenging life circumstances. Prominent theories of post-traumatic growth define it in terms of personality change, and as a result, this area of research should be of great interest to personality psychologists. Despite this fact, most of the research on this topic has not been sufficiently informed by relevant research in personality psychology, and much of the extant research suffers from significant methodological limitations. We review the literature on post-traumatic growth, with a particular focus on how researchers have conceptualized it and the specific methodological issues associated with these conceptualizations. We outline some ways in which personality science can both be enriched by the study of this phenomenon and inform rigorous research on post-traumatic growth and provide a series of guidelines for future research of post-traumatic growth as positive personality change