Health Risks From Mercury-Contaminated Fish: A Reassessment

Several Congressional bills and a pending EPA regulation would significantly cut mercury emissions from power plants, so as to reduce mercury-related neurological effects among children. There is, however, no estimate of the number of cases of neurological deficiencies that might be avoided by such emissions cuts. To inform policymakers, we develop estimates of the annual number of cases of neurodevelopmental effects among children in the United States, based on existing estimates of the exposure and dose-response relationships for prenatal exposure to methylmercury. Using data on emissions and deposition, we show that eliminating mercury emissions from U.S. power plants would prevent on the order of 10,000 cases of subtle neurological deficiencies per year. For a related paper, see Regulating Mercury Emissions: What Do We Know About Costs and Benefits?Environment, Health and Safety, Regulatory Reform

Timed Analysis of Security Protocols

We propose a method for engineering security protocols that are aware of timing aspects. We study a simplified version of the well-known Needham Schroeder protocol and the complete Yahalom protocol, where timing information allows the study of different attack scenarios. We model check the protocols using UPPAAL. Further, a taxonomy is obtained by studying and categorising protocols from the well known Clark Jacob library and the Security Protocol Open Repository (SPORE) library. Finally, we present some new challenges and threats that arise when considering time in the analysis, by providing a novel protocol that uses time challenges and exposing a timing attack over an implementation of an existing security protocol

Optical Photometry and Spectroscopy of the Suspected Cool Algol AV Delphini: Determination of the Physical Properties

We present new spectroscopic and BVRI photometric observations of the double-lined eclipsing binary AV Del ( period = 3:85 days) conducted over six observing seasons. A detailed radial velocity and light-curve analysis of the optical data shows the system to be most likely semidetached, with the less massive and cooler star filling its Roche lobe. The system is probably a member of the rare class of ‘‘cool Algol’’ systems, which are distinguished from the ‘‘classical’’ Algol systems in that the mass-gaining component is also a late-type star rather than a B- or A-type star. By combining the spectroscopic and photometric analyses, we derive accurate absolute masses for the components of M1 = 1.453 + 0.028 M and M2 = 0.705 + 0.014 M and radii of R1 = 2.632 + 0.030 R and R2 = 4.233 + 0.060 R, as well as effective temperatures of 6000 + 200 and 4275 + 150 K for the primary and secondary, respectively. There are no obvious signs of activity (spottedness) in the optical light curve of the binary

Winning Cores in Parity Games

We introduce the novel notion of winning cores in parity games and develop a deterministic polynomial-time under-approximation algorithm for solving parity games based on winning core approximation. Underlying this algorithm are a number properties about winning cores which are interesting in their own right. In particular, we show that the winning core and the winning region for a player in a parity game are equivalently empty. Moreover, the winning core contains all fatal attractors but is not necessarily a dominion itself. Experimental results are very positive both with respect to quality of approximation and running time. It outperforms existing state-of-the-art algorithms significantly on most benchmarks

Litigating Lead-Based Paint Hazards: Is It a Solution?

None.Environment, Health and Safety, Regulatory Reform

Min-Max Theorems for Packing and Covering Odd (u,v)(u,v)-trails

We investigate the problem of packing and covering odd $(u,v)$-trails in a graph. A $(u,v)$-trail is a $(u,v)$-walk that is allowed to have repeated vertices but no repeated edges. We call a trail odd if the number of edges in the trail is odd. Let $\nu(u,v)$ denote the maximum number of edge-disjoint odd $(u,v)$-trails, and $\tau(u,v)$ denote the minimum size of an edge-set that intersects every odd $(u,v)$-trail. We prove that $\tau(u,v)\leq 2\nu(u,v)+1$. Our result is tight---there are examples showing that $\tau(u,v)=2\nu(u,v)+1$---and substantially improves upon the bound of $8$ obtained in [Churchley et al 2016] for $\tau(u,v)/\nu(u,v)$. Our proof also yields a polynomial-time algorithm for finding a cover and a collection of trails satisfying the above bounds. Our proof is simple and has two main ingredients. We show that (loosely speaking) the problem can be reduced to the problem of packing and covering odd $(uv,uv)$-trails losing a factor of 2 (either in the number of trails found, or the size of the cover). Complementing this, we show that the odd-$(uv,uv)$-trail packing and covering problems can be tackled by exploiting a powerful min-max result of [Chudnovsky et al 2006] for packing vertex-disjoint nonzero $A$-paths in group-labeled graphs

Analysis of sorbents and catalysts used during a 90-day manned test

Chemical analysis of organic trace contaminants in simulated space station atmospheres desorbed from molecular sieve, silicon gel, and catalyst bed

Regulating Mercury Emissions: What Do We Know About Costs and Benefits?

United States policymakers are concerned with mercury emissions because mercury has potentially adverse effects on children whose mothers consumed contaminated fish while pregnant. Congress and the Environmental Protection Agency are considering different proposals to cut or even eliminate mercury emissions from oil and coal-fired power plants. We compare the cost of cutting power plants' mercury emissions with the likely reductions in the number of cases of subtle neurological effects. Given current scientific understanding, the health and environmental improvements are very unlikely to provide an economic justification for the costs of stringent controls on mercury emissions. In addition, if Congress or EPA were to regulate mercury emissions from power plants, an approach that used prices would be more efficient than one that limited the quantity of mercury emissions. For a related paper, see Health Risks From Mercury-Contaminated Fish: A Reassessment.