The impact of a collapsing gas bubble above rigid, notched walls is considered. Such surface crevices and imperfections often function as bubble nucleation sites, and thus have a direct relation to cavitation-induced erosion and damage structures. A generic configuration is investigated numerically using a second-order accurate compressible multi-component flow solver in a two-dimensional axisymmetric coordinate system. Results show that the crevice geometry has a significant effect on the collapse dynamics, jet formation, subsequent wave dynamics and interactions. The wall-pressure distribution associated with erosion potential is a direct consequence of development and intensity of these flow phenomena.

Drug Safety Communications (DSCs) are used by the Food and Drug Administration (FDA) to inform health care providers, patients, caregivers, and the general public about safety issues related to FDA-approved drugs. To assess patient knowledge of the messaging contained in DSCs related to the sleep aids zolpidem and eszopiclone, we conducted a large, cross-sectional patient survey of 1,982 commercially insured patients selected by stratified random sampling from the Optum Research Database who had filled at least two prescriptions for either zolpidem or eszopiclone between July 1, 2012 and June 30, 2013. Among the 594 respondents (32.7% response rate), two-thirds reported hearing generally about drug safety information prior to starting a new drug, with the remaining one-third “rarely” or “never” hearing such information. Providers and pharmacists were primary sources of drug safety information. Two-thirds of zolpidem users and half of eszopiclone users reported having heard about the related DSC messages, ability to accurately identify the major factual messages was limited (overall median 2 correct out of 5, with men and those reporting higher educational level scoring higher [2/5 vs. 1/5, p=0.001]). Respondents reacted to new drug safety information about their sleep aids by reporting that they would want to learn about alternative ways to help them sleep (70%) and seek out more information about the safety of their specific sleeping pill (59-78%). Opportunities may exist for the FDA to work with providers and pharmacies to help ensure the DSC information is more widely received and is more fully understood by those taking the affected medications.

Biomarkers can be powerful tools to guide diagnosis, treatment, and research. However, prudent use of biomarkers requires formal validation efforts. Although the data needed for biomarker validation has traditionally been hard to access, new research initiatives can ease this process.

The FDA's new table of surrogate endpoints used for drug approvals is an important step forward for overseeing the use of biomarkers in clinical trials. Nevertheless, we present several ways in which the table can be improved.

Environmentalism in the United States historically has been divided into its utilitarian and preservationist impulses, represented by Gifford Pinchot and John Muir, respectively. Pinchot advocated conservation of natural resources to be used for human purposes; Muir advocated protection from humans, for nature’s own sake. In the first half of the twentieth century, natural resource economics was firmly in Pinchot’s side of that schism. That position began to change as the postwar environmental movement gained momentum. In particular, John Krutilla, an economist at Resources for the Future, pushed economics to the point that it could embrace Muir’s vision as well as Pinchot’s. Krutilla argued that if humans preferred a preserved state to a developed one, then such preferences were every bit as “economic.” Either way, there were opportunity costs and an economic choice to be made.

Observations in experiments and simulations show that the kinematic behaviour of an elastic capsule, suspended and rotating in shear flow, depends upon the flow strength, the capsule membrane material properties and its at-rest shape. We develop a linear stability description of the periodically rotating base state of this coupled system, as represented by a boundary integral flow formulation with spherical harmonic basis functions describing the elastic capsule geometry. This yields Floquet multipliers that classify the stability of the capsule motion for elastic capillary numbers $Ca$ ranging from $Ca=0.01$ to 5. Viscous dissipation rapidly damps most perturbations. However, for all cases, a single component grows or decays slowly, depending upon $Ca$ , over many periods of the rotation. The transitions in this stability behaviour correspond to the different classes of rotating motion observed in previous studies.