Flavor Changing Neutral Current Effects and CP Violation in the Minimal 3-3-1 Model

We investigate in detail the flavor structure of the minimal 331 model and its implications for several flavor changing neutral current (FCNC) processes. In this model, where the weak SU(2)_L gauge group of the Standard Model is extended to a SU(3)_L, the by far dominant new contributions come from an additional neutral Z' gauge boson, that can transmit FCNCs at tree-level. At the same time, electroweak precision observables receive new contributions only at the loop level and do not constrain the model very strongly. In our analysis, we take into account new CP violating effects that have been neglected in earlier analyses, and account for a general flavor structure without reference to a certain parameterization of the new mixing matrix. We begin by studying the bounds obtained from quantities such as Delta M_K, epsilon_K, Delta M_{d/s} as well as sin 2 beta|_{J/psi K_S}, and go on to explore the implications for several clean rare decay channels, namely the decays K+->pi+ nu nu, K_L -> pi0 nu nu, B_{d/s} -> mu+ mu- and K_L -> pi0 l+l-. We find sizeable effects in all these decays, but the most interesting quantity turns out to be the B_s - bar B_s mixing phase beta_s, as measured in the mixing induced CP asymmetry of B_s -> J/psi phi, which can be large. In general, we find effects in purely hadronic channels to be larger than in (semi-)leptonic ones, due to a suppression of the Z'-lepton couplings.Comment: 29 pages, 11 figures, Some Comments and References added, version to appear in Phys Rev

La réglementation de l'audit est-elle dans l'intérêt public : quelques enseignements du modèle français

Cet article s'appuie sur les travaux académiques des dix dernières années pour évaluer les effets de la réglementation française visant à accroître l'indépendance des auditeurs. Pour les sociétés cotées en bourse, l'obligation de recourir à deux auditeurs se solde notamment par une moindre concentration du marché de l'audit : les Big Four détiennent une part de marché plus faible. Pour autant, les honoraires ne sont pas plus faibles, en raison vraisemblablement, d'une part, des coûts de coordination entre les deux auditeurs qui excèdent les bénéfices escomptés résultant d'un marché plus concurrentiel, d'autre part, de l'impossibilité de changer d'auditeur pendant la durée légale de six ans. Par ailleurs, la plus grande indépendance supposée, induite par cette réglementation spécifique, ne se traduit pas par une moindre gestion des résultats par les dirigeants français, malgré l'interdiction de facturer des honoraires de conseil. Ces constats empiriques nous conduisent à avancer que des assouplissements réglementaires du marché de l'audit pourraient s'avérer bénéfiques pour les actionnaires des entreprises françaisesAudit ; Réglementation; France ; Concentration ; Honoraires ; Gestion des résultats ; Audit ; Regulation ; France ; Concentration ; Audit fees ; Earnings management

Validating an Operational Flood Forecast Model Using Citizen Science in Hampton Roads, VA, USA

Changes in the eustatic sea level have enhanced the impact of inundation events in the coastal zone, ranging in significance from tropical storm surges to pervasive nuisance flooding events. The increased frequency of these inundation events has stimulated the production of interactive web-map tracking tools to cope with changes in our changing coastal environment. Tidewatch Maps, developed by the Virginia Institute of Marine Science (VIMS), is an effective example of an emerging street-level inundation mapping tool. Leveraging the Semi-implicit Cross-scale Hydro-science Integrated System Model (SCHISM) as the engine, Tidewatch operationally disseminates 36-h inundation forecast maps with a 12-h update frequency. SCHISM’s storm tide forecasts provide surge guidance for the legacy VIMS Tidewatch Charts sensor-based tidal prediction platform, while simultaneously providing an interactive and operationally functional forecast mapping tool with hourly temporal resolution and a 5 m spatial resolution throughout the coastal plain of Virginia, USA. This manuscript delves into the hydrodynamic modeling and geospatial methods used at VIMS to automate the 36-h street-level flood forecasts currently available via Tidewatch Maps, and the paradigm-altering efforts involved in validating the spatial, vertical, and temporal accuracy of the model. Supplementary material: Catch the King Tide GPS data points were collected by volunteers to effectively breadcrumb their path tracing the tidal high water contour lines by pressing the \u27Save Data\u27 button in the free Sea Level Rise Mobile App every few steps along the water\u27s edge during the high tide on the morning of November 5th, 2017. https://doi.org/10.25773/276h-2b4

Efficient gene targeting and foreign DNA removal by homologous recombination in the picoeukaryote Ostreococcus

With fewer than 8000 genes and a minimalist cellular organization, the green picoalga Ostreococcus tauri is one of the simplest photosynthetic eukaryotes. Ostreococcus tauri contains many plant-specific genes but exhibits a very low gene redundancy. The haploid genome is extremely dense with few repeated sequences and rare transposons. Thanks to the implementation of genetic transformation and vectors for inducible overexpression/knockdown this picoeukaryotic alga has emerged in recent years as a model organism for functional genomics analyses and systems biology. Here we report the development of an efficient gene targeting technique which we use to knock out the nitrate reductase and ferritin genes and to knock in a luciferase reporter in frame to the ferritin native protein. Furthermore, we show that the frequency of insertion by homologous recombination is greatly enhanced when the transgene is designed to replace an existing genomic insertion. We propose that a natural mechanism based on homologous recombination may operate to remove inserted DNA sequences from the genome