A Neglected Interdependency in Liability Theory

The standard economic model of bilateral precaution concludes that (in the absence of uncertainty, misperception, or error) all negligence-based liability rules induce socially optimal behavior by both injurers and victims. This paper generalizes the standard model to consider situations in which one party’s precaution affects not only expected accident loss, but also directly affects the other party’s effort—or cost—of taking precaution. If the injurer’s care affects the victim’s precaution costs (but not vice versa), most of the standard results continue to hold (except for strict liability with a defense of contributory negligence). If the victim’s precaution affects the injurer’s costs of care (but not vice versa), only strict liability with a defense of contributory negligence leads to the social optimum, while the other negligence-based rules lead to suboptimal outcomes. In the general case (where each party’s costs depend on both parties’ levels of precaution), none of the standard liability rules induce socially optimal behavior in both parties. The paper’s other main result concerns the possibility of self-interested, negligent behavior in equilibrium. Under negligence with a defense of contributory negligence, the only equilibrium is in the mixed strategies of both injurer and victim. This involves the parties choosing (with strictly positive probability) to behave negligently, and gives rise to the possibility of successful litigation in equilibrium, even though there is no uncertainty, misperception, or error. The paper concludes by considering the implications of these results for the design of liability rules.law and economics, and tort law

Stopping Deceptive Health Claims: The Need for a Private Right of Action Under Federal Law

This is the accepted version of the article. The final published version is available at https://journals.sagepub.com/doi/abs/10.1177/009885881664471

Probiotics: Achieving a Better Regulatory Fit

In 2007, the National Institutes of Health (NIH) launched the Human Microbiome Project (HMP), a $150 million initiative to characterize the microbial communities found at several different sites on the human body and to analyze the role of these microbes in human health and disease. Many lines of research have demonstrated the significant role of the microbiota in human physiology. The microbiota is involved, for example, in the healthy development of the immune system, prevention of infection from pathogenic or opportunistic microbes, and maintenance of intestinal barrier function. The HMP findings are helping us understand the role and variation of microorganisms within and across individuals, they are also promoting interest in the development of probiotic products. NIH set aside a portion of HMP funds to study the Ethical, Legal, and Social Implications (ELSI) of the HMP’s scientific goals. Among the funded ELSI studies was an effort to look at the current regulatory framework for probiotics and to determine if it is a good fit for the range of probiotics that are on the market, under development, or that may be developed in the future as a result of the HMP. This article reports on the findings of a Working Group consisting of NIH-funded HMP scientists, physicians, legal academics, government regulators, industry and consumer representatives, bioethicists, food and drug lawyers, and health policymakers who were assembled to address the adequacy of the current regulatory framework for probiotics under the HMP ELSI funded project. Specifically, after discussion of the features of probiotics that are relevant to their regulation and an overview of FDA’s current regulation of probiotics, the article addresses the following questions: 1) Do current regulations adequately address the safety of new probiotic products? 2) Should probiotic foods and dietary supplements be classified as drugs and required to go through the drug approval process? 3) What types of product characterization requirements are appropriate for probiotics? 4) Are current claim regulations appropriate for probiotics and, if not, how might they be improved

Three-dimensional photolithographic micropatterning: a novel tool to probe the complexities of cell migration

In order to independently study the numerous variables that influence cell movement, it will be necessary to employ novel tools and materials that allow for exquisite control of the cellular microenvironment. In this work, we have applied advanced 3D micropatterning technology, known as two-photon laser scanning lithography (TP-LSL), to poly(ethylene glycol) (PEG) hydrogels modified with bioactive peptides in order to fabricate precisely designed microenvironments to guide and quantitatively investigate cell migration. Specifically, TP-LSL was used to fabricate cell adhesive PEGRGDS micropatterns on the surface of non-degradable PEG-based hydrogels (2D) and in the interior of proteolytically degradable PEG-based hydrogels (3D). HT1080 cell migration was guided down these adhesive micropatterns in both 2D and 3D, as observed via time-lapse microscopy. Differences in cell speed, cell persistence, and cell shape were observed based on variation of adhesive ligand, hydrogel composition, and patterned area for both 2D and 3D migration. Results indicated that HT1080s migrate faster and with lower persistence on 2D surfaces, while HT1080s migrating in 3D were smaller and more elongated. Further, cell migration was shown to have a biphasic dependence on PEG-RGDS concentration and cells moving within PEG-RGDS micropatterns were seen to move faster and with more persistence over time. Importantly, the work presented here begins to elucidate the multiple complex factors involved in cell migration, with typical confounding factors being independently controlled. The development of this unique platform will allow researchers to probe how cells behave within increasingly complex 3D microenvironments that begin to mimic specifically chosen aspects of the in vivo landscape

Saturable Absorption of Free-Electron Laser Radiation by Graphite near the Carbon K-Edge

The interaction of intense light with matter gives rise to competing nonlinear responses that can dynamically change material properties. Prominent examples are saturable absorption (SA) and two-photon absorption (TPA), which dynamically increase and decrease the transmission of a sample depending on pulse intensity, respectively. The availability of intense soft X-ray pulses from free-electron lasers (FELs) has led to observations of SA and TPA in separate experiments, leaving open questions about the possible interplay between and relative strength of the two phenomena. Here, we systematically study both phenomena in one experiment by exposing graphite films to soft X-ray FEL pulses of varying intensity. By applying real-time electronic structure calculations, we find that for lower intensities the nonlinear contribution to the absorption is dominated by SA attributed to ground-state depletion; our model suggests that TPA becomes more dominant for larger intensities (\u3e1014 W/cm2). Our results demonstrate an approach of general utility for interpreting FEL spectroscopies

Advancing In Situ Modeling of ICMEs: New Techniques for New Observations

It is generally known that multi-spacecraft observations of interplanetary coronal mass ejections (ICMEs) more clearly reveal their three-dimensional structure than do observations made by a single spacecraft. The launch of the STEREO twin observatories in October 2006 has greatly increased the number of multipoint studies of ICMEs in the literature, but this field is still in its infancy. To date, most studies continue to use on flux rope models that rely on single track observations through a vast, multi-faceted structure, which oversimplifies the problem and often hinders interpretation of the large-scale geometry, especially for cases in which one spacecraft observes a flux rope, while another does not. In order to tackle these complex problems, new modeling techniques are required. We describe these new techniques and analyze two ICMEs observed at the twin STEREO spacecraft on 22-23 May 2007, when the spacecraft were separated by ~8 degrees. We find a combination of non-force-free flux rope multi-spacecraft modeling, together with a new non-flux rope ICME plasma flow deflection model, better constrains the large-scale structure of these ICMEs. We also introduce a new spatial mapping technique that allows us to put multispacecraft observations and the new ICME model results in context with the convecting solar wind. What is distinctly different about this analysis is that it reveals aspects of ICME geometry and dynamics in a far more visually intuitive way than previously accomplished. In the case of the 22-23 May ICMEs, the analysis facilitates a more physical understanding of ICME large-scale structure, the location and geometry of flux rope sub-structures within these ICMEs, and their dynamic interaction with the ambient solar wind

A Compact Beam Stop for a Rare Kaon Decay Experiment

We describe the development and testing of a novel beam stop for use in a rare kaon decay experiment at the Brookhaven AGS. The beam stop is located inside a dipole spectrometer magnet in close proximity to straw drift chambers and intercepts a high-intensity neutral hadron beam. The design process, involving both Monte Carlo simulations and beam tests of alternative beam-stop shielding arrangements, had the goal of minimizing the leakage of particles from the beam stop and the resulting hit rates in detectors, while preserving maximum acceptance for events of interest. The beam tests consisted of measurements of rates in drift chambers, scintilation counter hodoscopes, a gas threshold Cherenkov counter, and a lead glass array. Measurements were also made with a set of specialized detectors which were sensitive to low-energy neutrons, photons, and charged particles. Comparisons are made between these measurements and a detailed Monte Carlo simulation.Comment: 39 pages, 14 figures, submitted to Nuclear Instruments and Method