Ring closing metathesis in protic media by means of a neutral and polar ruthenium benzylidene complex

The ring closing olefine metathesis in protic solvents using a new ruthenium benzylidene complex is described

Synthesis of Telechelic Polyisoprene via Ring-Opening Metathesis Polymerization in the Presence of Chain Transfer Agent

Telechelic polyisoprene was synthesized via the ring-opening metathesis polymerization (ROMP) of 1,5-dimethyl-1,5-cyclooctadiene (DMCOD) in the presence of cis-1,4-diacetoxy-2-butene as a chain transfer agent (CTA). This method afforded telechelic polymer in excellent yield, and the acetoxy groups were successfully removed to yield α,ω-hydroxy end-functionalized polyisoprene with potential for subsequent reactions. Efficient, quantitative incorporation of CTA was achieved, and NMR spectroscopy was utilized to confirm the chemical identity of the polymer end groups. Polymerization of discrete DMCOD monomer generated polyisoprene with excellent regioregularity in the polymer backbone. Successful ROMP of sterically challenging DMCOD in the presence of a CTA for chain end-functionalization was borne out through screening of a variety of Ru-based olefin metathesis catalysts

An annotated checklist of the Coleoptera (Insecta) of the Cayman Islands, West Indies

A faunal list of 605 species of Coleoptera in 396 genera in 63 families is presented for the Cayman Islands. For most species, island and locality within island collecting information is provided

Three-Dimensional Core-Collapse Supernova Simulations with Multi-Dimensional Neutrino Transport Compared to the Ray-by-Ray-plus Approximation

Self-consistent, time-dependent supernova (SN) simulations in three spatial dimensions (3D) are conducted with the Aenus-Alcar code, comparing, for the first time, calculations with fully multi-dimensional (FMD) neutrino transport and the ray-by-ray-plus (RbR+) approximation, both based on a two-moment solver with algebraic M1 closure. We find good agreement between 3D results with FMD and RbR+ transport for both tested grid resolutions in the cases of a 20 solar-mass progenitor, which does not explode with the employed simplified set of neutrino opacities, and of an exploding 9 solar-mass model. This is in stark contrast to corresponding axisymmetric (2D) simulations, which confirm previous claims that the RbR+ approximation can foster explosions in 2D in particular in models with powerful axial sloshing of the stalled shock due to the standing accretion shock instability (SASI). However, while local and instantaneous variations of neutrino fluxes and heating rates can still be considerably higher with RbR+ transport in 3D, the time-averaged quantities are very similar to FMD results because of the absence of a fixed, artificial symmetry axis that channels the flow. Therefore, except for stochastic fluctuations, the neutrino signals and the post-bounce evolution of 3D simulations with FMD and RbR+ transport are also very similar, in particular for our calculations with the better grid resolution. Higher spatial resolution has clearly a more important impact than the differences by the two transport treatments. Our results back up the use of the RbR+ approximation for neutrino transport in 3D SN modeling.Comment: 25 pages, 16 figures; referee comments included, new appendix added; accepted by Ap

An Explicit SU(12) Family and Flavor Unification Model

An explicit SUSY SU(12) unification model with three light chiral families is presented which avoids any external flavor symmetries. The hierarchy of quark and lepton masses and mixings is explained by higher dimensional Yukawa interactions involving Higgs bosons containing SU(5) singlet fields with VEVs appearing at or below the SUSY GUT scale of 2 \times 10^{16} GeV, approximately 50 times smaller than the SU(12) unification scale. The model has been found to be in good agreement with the observed quark and lepton masses and mixings, with nearly all prefactors of O(1) in the four Dirac and one Majorana fermion mass matrices.Comment: 7 pages, in proceedings of the CETUP*2012 Workshop, Lead, SD, 10 July - 1 August 201

Policy Implications of Crop Yield and Revenue Variability at Differing Levels of Disaggregation

Revenue variability at different levels of aggregation has been the focus of several proposals to reform U.S. commodity programs with the 2007 farm bill. In this paper, we estimate revenue variabilityyear-to-year deviations from expected revenuefor corn, soybeans, and cotton at four levels of aggregation: national, state, county and farm. We examine the factors that cause revenue variability and how differences across crops and regions would affect producers risks. We find that national-level revenue variability is nearly double national-level yield variability. Spatial disaggregation increases price and yield variability, but yield variability increases more rapidly than price and revenue variability. A hypothetical national-level revenue program would reduce risk at the average farm-level by slightly more than 8 percent for corn, about 7 percent for soybeans and about 21 percent for cotton. If one integrates farm-level revenue coverage with the national-level program the percent risk reduction more than doubles for both corn and soybeans. Although the increase in risk reduction between the simple national and the integrated program is proportionately less for cotton, the total risk reduction for cotton is the greatest among the three crops.Agricultural and Food Policy,

Evaluating Emergency Takings: Flattening the Economic Curve

Desperate times may breed desperate measures, but when do desperate measures undertaken as a response to an emergency trigger the Fifth Amendment’s requirement that the government provides just compensation when it takes private property for public use? The answer to that question has commonly been posed as a choice between the “police power”—a sovereign government’s power to regulate property’s use in order to further the public health, safety, and welfare—and the eminent domain power, the authority to seize private property for public use with the corresponding requirement to pay compensation. But that should not be the question. After all, emergencies do not increase government power, nor do they necessarily alter constitutional rights, and an invocation of police power by itself does not solve the compensation question but is merely the predicate issue: all governmental actions must be for the public health, safety, or welfare, in the same way that an exercise of the eminent domain power must be for a public use. This Article provides a roadmap for analyzing these questions, hoping that it will result in a more consistent approach for resolving claims for compensation that arise out of claims of emergencies. This Article analyzes the potential takings claims stemming from emergency measures, mostly under the current takings doctrine. Which types of claims are likely to succeed or fail? In “normal” times, it is very difficult to win a regulatory takings claim for compensation. In the midst of emergencies—real or perceived—the courts are even more reluctant to provide a remedy, even when they should, and emergencies are a good time to make bad law, especially in takings law. Can a better case be made analytically for compensation? In sum, this Article argues there is no blanket immunity from the requirement to provide just compensation when property is taken simply because the government claims to be acting in response to an emergency, even though its actions and reasons may satisfy the rational basis test. Instead, claims that the taking is not compensable because of the exigency of an emergency should only win the day if the government successfully shows that the measure was actually needed to avoid imminent danger posed by the property owner’s use and that the restriction on use was narrowly tailored to further that end