Comparison of K+K^+ and e−e^- Quasielastic Scattering

We formulate $K^+$-nucleus quasielastic scattering in a manner which closely parallels standard treatments of $e^-$-nucleus quasielastic scattering. For $K^+$ scattering, new responses involving scalar contributions appear in addition to the Coulomb (or longitudinal) and transverse $(e,e')$ responses which are of vector character. We compute these responses using both nuclear matter and finite nucleus versions of the Relativistic Hartree Approximation to Quantum Hadrodynamics including RPA correlations. Overall agreement with measured $(e,e')$ responses and new $K^+$ quasielastic scattering data for $^{40}$Ca at |\qs|=500 MeV/c is good. Strong RPA quenching is essential for agreement with the Coulomb response. This quenching is notably less for the $K^+$ cross section even though the new scalar contributions are even more strongly quenched than the vector contributions. We show that this ``differential quenching'' alters sensitive cancellations in the expression for the $K^+$ cross section so that it is reduced much less than the individual responses. We emphasize the role of the purely relativistic distinction between vector and scalar contributions in obtaining an accurate and consistent description of the $(e,e')$ and $K^+$ data within the framework of our nuclear structure model.Comment: 26 pages, 5 uuencoded figures appended to end of this fil

Physical Processes in Star Formation

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00693-8.Star formation is a complex multi-scale phenomenon that is of significant importance for astrophysics in general. Stars and star formation are key pillars in observational astronomy from local star forming regions in the Milky Way up to high-redshift galaxies. From a theoretical perspective, star formation and feedback processes (radiation, winds, and supernovae) play a pivotal role in advancing our understanding of the physical processes at work, both individually and of their interactions. In this review we will give an overview of the main processes that are important for the understanding of star formation. We start with an observationally motivated view on star formation from a global perspective and outline the general paradigm of the life-cycle of molecular clouds, in which star formation is the key process to close the cycle. After that we focus on the thermal and chemical aspects in star forming regions, discuss turbulence and magnetic fields as well as gravitational forces. Finally, we review the most important stellar feedback mechanisms.Peer reviewedFinal Accepted Versio

The Psychological Science Accelerator’s COVID-19 rapid-response dataset

In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data

Percutaneous Cardiopulmonary Bypass

We have employed a percutaneous cardiopulmonary bypass (PCPB) system during high risk interventional procedures in the cardiac catheterization laboratory. Eight patients (group 1) were elective and six (group 2) were emergencies. Group 1 (ages 39 - 80 years, mean 56 years) includes seven patients who were high risk percutaneous transluminal coronary angioplasty (PTCA) and one patient who underwent balloon aortic valvuloplasty. Group 2 (ages 54 - 80 years, mean 66 years) were in cardiogenic shock, five of whom had arrested. All patients were fully heparinized (300 iu•Kg1) prior to percutaneous insertion of 17 - 19F cannulae. Group 1 patients underwent ilio-femoral angiography prior to cannulae insertion. Mean bypass time was 103 minutes (range 37 - 231 minutes) in group 1 and 406 minutes (range 40 -1781 minutes) in group 2. Bypass was instituted at a flow of 0.5 1•min-1 in group 1, flow was increased if chest pain, ECG changes or hypotension occurred, (maximum flow 0.5-2.5 1•min-1 mean flow 1.7 1•min-1) Maximum bypass flow in group 2 was 4 - 5.5 1•min-1 (mean 4.5 1•min-1). Mean fluid infusion during PCPB was 200 ml•hour-1 in group 1 and 385 ml•hour-1 in group 2. The mortality was four patients, all in group 2. Three patients were unable to support their circulation when weaned from PCPB and one patient had a massive intrathoracic bleed such that PCPB could not be maintained. There were no procedural complications associated with cannulae insertion or perfusion management. Of the survivors two had an unexplained haematuria (normal plasma haemoglobin). Two patients bled from the cannulation site following cannulae removal, haemostasis was achieved without surgical intervention

Investigation of Isovector Axial Response via Polarization Transfer in the (pol.p, pol.n) Reaction

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440