A Unified Theory of Matter Genesis: Asymmetric Freeze-In

We propose a unified theory of dark matter (DM) genesis and baryogenesis. It explains the observed link between the DM density and the baryon density, and is fully testable by a combination of collider experiments and precision tests. Our theory utilises the "thermal freeze-in" mechanism of DM production, generating particle anti-particle asymmetries in decays from visible to hidden sectors. Calculable, linked, asymmetries in baryon number and DM number are produced by the feeble interaction mediating between the two sectors, while the out-of-equilibrium condition necessary for baryogenesis is provided by the different temperatures of the visible and hidden sectors. An illustrative model is presented where the visible sector is the MSSM, with the relevant CP violation arising from phases in the gaugino and Higgsino masses, and both asymmetries are generated at temperatures of order 100 GeV. Experimental signals of this mechanism can be spectacular, including: long-lived metastable states late decaying at the LHC; apparent baryon-number or lepton-number violating signatures associated with these highly displaced vertices; EDM signals correlated with the observed decay lifetimes and within reach of planned experiments; and a prediction for the mass of the dark matter particle that is sensitive to the spectrum of the visible sector and the nature of the electroweak phase transition.Comment: LaTeX, 22 pages, 6 figure

A Trapping Experiment to Estimate the Bluegill Population in a Farm Pond

Estimates of fish populations from recapture of marked fish have, on several occasions, yielded estimates far below the population later shown to be present (Krumholz 1944, Carlander and Lewis 1948, Fredin 1950, Carlander 1952). Fredin (1950) suggested that the recapture of the fish by some method different from that used in the original capture might give less biased results. In the present investigation the bluegill population was estimated by the marking and recovery technique using seines and baited wire traps

ECONOMIC INSIGHTS INTO THE SITING PROBLEM: AN APPLICATION OF THE EXPECTED UTILITY MODEL

Despite the generally recognized need for facilities such as power plants, landfills, prisons, and medical laboratories, finding host sites has become extremely difficult. This study uses the expected utility (EU) model to explain individiuals' preferences in the hypothetical case of siting a municipal solid waste composting facility. The three principal factors which EU theory prescribes would affect the decision process- benefits of the proposed facility, losses from the facility, and the (perceived) probability of various scenarios occurring- embodied by the variables in a multinomial logit model explain a substantial amount of the variation in siting decisions.Public Economics,

Cationic Alkylaluminum-Complexed Zirconocene Hydrides: NMR-Spectroscopic Identification, Crystallographic Structure Determination, and Interconversion with Other Zirconocene Cations

The ansa-zirconocene complex rac-Me_2Si(1-indenyl)_2ZrCl_2 ((SBI)ZrCl_2) reacts with diisobutylaluminum hydride and trityl tetrakis(perfluorophenyl)borate in hydrocarbon solutions to give the cation [(SBI)Zr(μ-H)_3(Al^iBu_2)_2]^+, the identity of which is derived from NMR data and supported by a crystallographic structure determination. Analogous reactions proceed with many other zirconocene dichloride complexes. [(SBI)Zr(μ-H)_3(Al^iBu2)_2]^+ reacts reversibly with ClAl^iBu_2 to give the dichloro-bridged cation [(SBI)Zr(μ-Cl)_2Al^iBu_2]^+. Reaction with AlMe_3 first leads to mixed-alkyl species [(SBI)Zr(μ-H)_3(AlMe_x^iBu_(2−x))_2^]+ by exchange of alkyl groups between aluminum centers. At higher AlMe_3/Zr ratios, [(SBI)Zr(μ-Me)_2AlMe_2]^+, a constituent of methylalumoxane-activated catalyst systems, is formed in an equilibrium, in which the hydride cation [(SBI)Zr(μ-H)_3(AlR_2)_2]^+ strongly predominates at comparable HAl^iBu_2 and AlMe_3 concentrations, thus implicating the presence of this hydride cation in olefin polymerization catalyst systems

Eccentricity of the Apical System and Peristome of Sand Dollars (Echinodermata: Echinoidea: Clypeasteroida: Scutellina)

Eccentricity, location of structures away from a central position, is associated with directional movement. Although sand dollars have directional movement, only eccentricity of the anus is apparent. Eccentricity of the apical system and peristome is less apparent. We have found the apical system and the peristome are statistically significantly slightly anterior in Mellita tenuis, Mellita quinquiesperforata, Mellita isometra, and Encope aberrans. The apical system of Leodia sexiesperforata is central and that of Echinarachnius parma is anterior, whereas the peristome of both is statistically significantly slightly posterior. The usual selective pressure for pronounced anterior location of the mouth in animals with directional movement may be countered by the mode of feeding in sand dollars that utilizes the oral surface. The basis for the eccentricity of the apical system is not known

Securities trading and settlement in Europe: issues and outlook

The institutional arrangements for trading and settling securities in Europe remain fragmented along national lines, making cross-border trading costly. Consolidation efforts are under way, however, and major market centers have now emerged in France, Germany, and the United Kingdom. Although the restructuring of trading and settlement systems should bring the European Community closer to its goal of a single capital market, changes in corporate governance and the competitive environment may raise significant regulatory issues.Capital market - Europe ; Securities - Europe ; International finance