Correlated decay of triplet excitations in the Shastry-Sutherland compound SrCu2_2(BO3_3)2_2

The temperature dependence of the gapped triplet excitations (triplons) in the 2D Shastry-Sutherland quantum magnet SrCu$_2$(BO$_3$)$_2$ is studied by means of inelastic neutron scattering. The excitation amplitude rapidly decreases as a function of temperature while the integrated spectral weight can be explained by an isolated dimer model up to 10~K. Analyzing this anomalous spectral line-shape in terms of damped harmonic oscillators shows that the observed damping is due to a two-component process: one component remains sharp and resolution limited while the second broadens. We explain the underlying mechanism through a simple yet quantitatively accurate model of correlated decay of triplons: an excited triplon is long-lived if no thermally populated triplons are near-by but decays quickly if there are. The phenomenon is a direct consequence of frustration induced triplon localization in the Shastry--Sutherland lattice.Comment: 5 pages, 4 figure

The Interior Dynamics of Water Planets

The ever-expanding catalog of detected super-Earths calls for theoretical studies of their properties in the case of a substantial water layer. This work considers such water planets with a range of masses and water mass fractions (2 to 5 M_Earth, 0.02% to 50% H2 O). First, we model the thermal and dynamical structure of the near-surface for icy and oceanic surfaces, finding separate regimes where the planet is expected to maintain a subsurface liquid ocean and where it is expected to exhibit ice tectonics. Newly discovered exoplanets may be placed into one of these regimes given estimates of surface temperature, heat flux, and gravity. Second, we construct a parameterized convection model for the underlying ice mantle of higher ice phases, finding that materials released from the silicate iron core should traverse the ice mantle on the timescale of 0.1 to 100 megayears. We present the dependence of the overturn times of the ice mantle and the planetary radius on total mass and water mass fraction. Finally, we discuss the implications of these internal processes on atmospheric observables.Comment: 9 page 4 figure

Role induction, perseverance in therapy and psychotherapy outcome

Therapists and researchers alike consider premature termination to be problematic to assessing true outcomes in psychotherapy. Some feel that it is the number one problem facing both researchers and clinicians today. The role induction (RI) procedure, or educating clients about the purpose and process of therapy, is one method that has been found to lower premature termination rates as well as increase positive outcomes in psychotherapy. The current study was designed to investigate the effects of a RI onpremature termination rates, outcome, and measures of therapeutic alliance. The mechanism of RI as a medium in which to influence clients to remain in therapy was also investigated. Sixty-eight clients and their therapists participated in the current research. Each client and the therapist completed outcome and alliance measures at specified points in the therapy. Half (n = 34) of the clients received a role induction and the other half acted as a control group. The role induction was in the form of a 13-minute videotape entitled What to Expect in Psychotherapy

Assessing police applicants : a further look at MMPI and Rorschach data

Currently, there are many problems associated with the process of police officer selection. Focusing specifically on psychological testing instruments, the MMPI is the most widely used instrument in police officer selection. The general MMPI profile for the police population, however, is relatively flat. Researchers have tried to pinpoint scales which will differentiate officers, but consistent results have been elusive. The present research was undertaken to determine if the Rorschach could be effectively utilized in conjunction with the information provided by the MMPI in the police selection process. Protocols (N = 53) from police applicants were obtained and found to be within normal limits on the MMPI validity scales and contained valid Rorschach protocols. The Rorschach protocols were then scored and analyzed. Results indicate that this sample differed from the normative data found in Exner\u27s Comprehensive System (1993) on variables of human movement (M), active movement, Populars, extended Form quality (X+%), unusual Form quality (Xu%), texture (T), Lambda (L), and on the Erlebnistypus (EB) measure and the Depression Index. Based on these findings, it appears that the Rorschach could be a viable psychological test to be used in conjunction with the MMPI to screen police applicants. Further research into the use of these two tests, in a sample where follow-up information is available, is warranted

Role induction, perseverance in therapy and psychotherapy outcome

Therapists and researchers alike consider premature termination to be problematic to assessing true outcomes in psychotherapy. Some feel that it is the number one problem facing both researchers and clinicians today. The role induction (RI) procedure, or educating clients about the purpose and process of therapy, is one method that has been found to lower premature termination rates as well as increase positive outcomes in psychotherapy. The current study was designed to investigate the effects of a RI onpremature termination rates, outcome, and measures of therapeutic alliance. The mechanism of RI as a medium in which to influence clients to remain in therapy was also investigated. Sixty-eight clients and their therapists participated in the current research. Each client and the therapist completed outcome and alliance measures at specified points in the therapy. Half (n = 34) of the clients received a role induction and the other half acted as a control group. The role induction was in the form of a 13-minute videotape entitled What to Expect in Psychotherapy

Spin density wave induced disordering of the vortex lattice in superconducting La2−x_{2-x}Srx_xCuO4_4

We use small angle neutron scattering to study the superconducting vortex lattice in La$_{2-x}$Sr$_x$CuO$_4$ as a function of doping and magnetic field. We show that near optimally doping the vortex lattice coordination and the superconducting coherence length $\xi$ are controlled by a van-Hove singularity crossing the Fermi level near the Brillouin zone boundary. The vortex lattice properties change dramatically as a spin-density-wave instability is approached upon underdoping. The Bragg glass paradigm provides a good description of this regime and suggests that SDW order acts as a novel source of disorder on the vortex lattice.Comment: Accepted in Phys. Rev.

Prisons and Pandemics

This Article focuses on how to balance public health, public safety, and incarcerated people’s legal rights when implementing a program for early release from confinement. Ethical, epidemiological, and legal arguments all point to a need for an immediate reduction in the incarcerated population. However, this leaves open several points of reasonable disagreement about how to manage early release. These include how to set priorities for processing and releasing individuals across the country. For example, officials could prioritize screening individuals who are housed in facilities that have been hit hard by infection; or by screening individuals who have a safe place to quarantine post-release; or individuals who are being held for violations of parole, lower level and nonviolent crimes, or prior to their trials; or individuals who are most vulnerable to coronavirus; or individuals who have already served most of their sentences; and so on. This Article discusses how to set priorities for safely and quickly returning incarcerated individuals to their communities during a life-threatening outbreak. In Part II, we establish why incarcerated people are especially vulnerable during a public health emergency. For a variety of reasons, incarcerated people are more likely than the general public to acquire and to experience negative outcomes from infectious diseases, putting their health and the health of surrounding communities at risk. In Part III, we discuss the pandemic response taken by federal and state prisons and local jails and explain why it has had little success. For the most part, releases have been slow and discretionary, meaning that whether an individual is released is “like the luck of the draw” because there are “wardens in certain prisons that will get right on it, and some that won’t release a soul.” We also outline some of the recommendations proposed by bodies like the ACLU and members of Congress. Careful consideration of these different plans for releasing incarcerated people from confinement is important in order to prepare for COVID-19 in the coming months and to look toward future pandemics. In Part IV, we summarize the moral, practical, and legal arguments for making the health of incarcerated people a priority during a pandemic. These arguments rely on the ethical principle that we are morally required to protect individuals who have been deprived of the liberty to protect themselves; empirical evidence indicating that high infection rates within correctional facilities have serious public health consequences for surrounding communities; and legal precedent that suggests that incarcerated people have a right to protection from infectious diseases. Taking these arguments together, it is reasonable to support a substantial reduction in jail and prison populations, irrespective of one’s general views about the ethics and purpose of mass incarceration. In Part V, we delve into the details of how to release incarcerated people. There have been several general recommendations outlining broad guidelines for doing so. However, the ethical priorities that underlie these different recommendations have not been made explicit and have not been considered together. In this Part, we identify the various ethical considerations relevant to early release, and we argue that five factors should be given special priority. These are (1) risk of recidivism for a violent offense, (2) presumption of innocence for the accused, (3) risk of mortality from coronavirus, (4) proportion of sentence served, and (5) responsibilities to third parties