7,799 research outputs found

    (SUSY) Higgs Search at the LHC

    Full text link
    The discovery of the Standard Model (SM) or supersymmetric (SUSY) Higgs bosons belongs to the main endeavors of the Large Hadron Collider (LHC). In this article the status of the signal and background calculations for Higgs boson production at the LHC is reviewed.Comment: 6 pages, 4 figures, plenary talk given at SUSY08, Seoul, Kore

    Generation of Transgenic Mice to Evaluate Promoter Activity and Specificity of Two Human Endogenous Retrovirus Long Terminal Repeats = Untersuchungen zur Promotor-AktivitÀt und -SpezifitÀt von zwei Long Terminal Repeats humaner endogener Retroviren in transgenen MÀusen

    Get PDF
    Generation of Transgenic Mice to Evaluate Promoter Activity and Specificity of two Human Endogenous Retrovirus Long Terminal Repeats Human Endogenous Retrovirus Long Terminal Repeats (HERV-LTRs) comprise 1.8% of the human genome (52.7 Mb). These sequences contain all the signal structures necessary for the regulation of gene transcription, such as promoters, enhancers and transcription factor binding sites. There is evidence that HERV-LTRs regulate gene expression in tissue-specific manner. This potential could be used to drive the expression of therapeutic genes, delivered by retroviral vector systems, in a safe and efficient manner. The HERV-H-H6 LTR and the HERV-L LTR were chosen for the generation of transgenic mice. Their promoter activity and specificity had prior been tested in a luciferase expression vector in vitro (Schoen et al., 2001). HERV-L was cloned into a luciferase expression vector and HERV-H-H6 was inserted into a enhanced green fluorescent protein (EGFP) expression vector. Transgenic mice were generated by DNAmicroinjection into pronuclei of zygotes. One pBL-HERV-L transgenic line and four pEGFP-HERV-H-H6 transgenic lines were established and analyzed. While the HERV-L promoter was not active in transgenic animals, pEGFP-HERV-H-H6 was expressed in gonads of mice of two transgenic lines. As only a single, non-expressing transgenic line was available, HERV-L promoter activity and specificity could not be evaluated. Additional transgenic lines have to be established. Expression level and pattern of the HERV-H-H6 promoter indicate specificity for gonad tissue. Whether the HERV-H-H6 promoter activity is linked to steroid production in cells remains to be clarified. Evaluating promoter activity in transgenic mice in two different expression vectors is not exclusively about the promoters, but also involves knowledge about the reporter genes. Advantages and limits of current applications of both luciferase and EGFP (with focus on the EGFP gene) are described in REVIEW OF THE LITERATURE. The conjunction of EGFP with the HERV-H-H6 promoter is to be seen critically, as all published methods for detection of EGFP in mice are described with EGFP linked to strong promoters. Problems like autofluorescence in fluorescence microscopy might be encountered when weaker promoters, such as HERV-LTRs, drive EGFP expression.Untersuchungen zur Promotor-AktivitĂ€t und –SpezifitĂ€t von zwei Long Terminal Repeats humaner endogener Retroviren in transgenen MĂ€usen 1.8% des humanen Genoms bestehen aus Long Terminal Repeats Humaner Endogener Retroviren (HERV-LTRs). Solche Sequenzen enthalten alle Strukturen, die fĂŒr die Regulierung von Transkription benötigt werden: Promotoren, Enhancer and Bindungsstellen fĂŒr Transkriptionsfaktoren. Es gibt Hinweise, daß HERV-LTRs die Expression von Genen gewebespezifisch regulieren können. Eingebaut in retrovirale GenfĂ€hren, könnten HERV-LTRs therapeutische Gene sicher und effizient aktivieren. Zur Generierung transgener MĂ€use wurden der HERV-H-H6 LTR und der HERV-L LTR ausgewĂ€hlt. Deren Promoter Eigenschaften, wie AktivitĂ€t und GewebespezifitĂ€t, waren bereits in vitro untersucht worden (Schoen et al., 2001). Der HERV-L LTR wurde in einen Luciferase Expressionsvektor und der HERV-H-H6 LTR in einen Enhanced Green Fluorescent Protein (EGFP) Expressionsvektor kloniert. Transgene MĂ€use enstanden durch DNA-Mikroinjektion in den Vorkern von Zygoten. Eine pBL-HERV-L transgene Linie und vier pEGFP-HERV-H-H6 transgene Linien wurden gezĂŒchtet und auf Integration sowie Expression der Genkonstrukte untersucht. WĂ€hrend der HERV-L Promoter keine AktivitĂ€t zeigte, war Expression von pEGFP-HERV-H-H6 in KeimdrĂŒsen von MĂ€usen aus zwei transgenen Linien nachweisbar. Da fĂŒr das Genkonstrukt pBL-HERV-L nur eine einzige, nicht-exprimierende transgene Linie aufgebaut werden konnte, können keine Aussagen ĂŒber die AktivitĂ€t und GewebespezifitĂ€t des HERV-L Promoters getroffen werden. Zu diesem Zwecke mĂŒssten weitere pBL-HERV-L transgene Linien untersucht werden. Das Expressionsmuster des pEGFP-HERV-H-H6 Genkonstruktes, weißt auf eine mögliche GewebespezifitĂ€t fĂŒr KeimdrĂŒsen hin. Eine eventuelle VerknĂŒpfung der AktivitĂ€t des HERV-H-H6 LTRs mit der Produktion von Steroidhormonen mĂŒsste weitergehend geklĂ€rt werden.Da in dieser Arbeit zwei unterschiedliche Reportergen Systeme in der Maus angewandt wurden, sind im Literaturteil Vorteile und EinschrĂ€nkungen von aktuellen Nachweisverfahren beider Reportergene, mit Schwerpunkt EGFP, in Mausgewebe zusammengefasst. Die Verbindung von EGFP mit dem HERV-H-H6 Promoter ist als kritisch zu beurteilen: Alle beschriebenen Nachweisverfahren fĂŒr EGFP in der Maus grĂŒnden auf Mausmodellen, in denen das EGFP von einem starken Promoter kontrolliert wurde. Bei potenziell schwĂ€cheren Promotoren, wie HERV-LTRs, können Probleme auftreten, wie z.B. Autofluoreszenz bei der Fluoreszenzmikroskopie

    Polya urns via the contraction method

    Full text link
    We propose an approach to analyze the asymptotic behavior of P\'olya urns based on the contraction method. For this, a new combinatorial discrete time embedding of the evolution of the urn into random rooted trees is developed. A decomposition of these trees leads to a system of recursive distributional equations which capture the distributions of the numbers of balls of each color. Ideas from the contraction method are used to study such systems of recursive distributional equations asymptotically. We apply our approach to a couple of concrete P\'olya urns that lead to limit laws with normal limit distributions, with non-normal limit distributions and with asymptotic periodic distributional behavior.Comment: minor revision; accepted for publication in Combinatorics, Probability & Computing (Special issue dedicated to the memory of Philippe Flajolet

    The emergence of cohabitation as a first union and its later stability: the case of Hungarian women

    Get PDF
    With the transition of the 1990s in the countries of Central and Eastern Europe, the demographic behavior of their populations has changed drastically. This paper focuses on Hungary where some of these developments like falling marriage rates were evident even before 1990. We examine the emergence of cohabitation as a first union and the stability of such relationships. Are they rather transformed into marriage or do they end in dissolution? How long do Hungarian woman stay in these unions? In addition to some descriptive statistics we apply event history analysis because this allows us to study the impact of individual-level characteristics on such choices. The data used is the Hungarian Generations and Gender Survey collected around November 2001. The analysis shows that there are marked differences in behavior between periods and that factors like pregnancy or employment do influence the decision for cohabitation as well as its further development.Hungary

    International Integration and Regional Development in China

    Get PDF
    Concerns about the duration of China?s growth and hence the question of a permanent significant contribution of China to world economic growth relate, amongst other things, to the problem of reducing regional disparity in China. While China?s high average growth is driven by a small number of rapidly developing provinces, the majority of provinces have experienced more moderate development. To obtain broad continous growth it is important to identify the determinants of provincial growth. Therefore, we introduce a stylized model of regional development which is characterized by two pillars: (i) International integration indicated by FDI and/or trade lead to imitation of international technologies, technology spill overs and temporary dynamic scale economies, and (ii) domestic factors indicated by human and real capital available through interregional factor mobility. Using panel data analysis and GMM estimates our empirical analysis supports the predictions from our theoretical model of regional development. Positive and significant coefficients for FDI and trade support the importance of international integration and technology imitation. A negative and significant lagged GDP per capita indicates a catching up, non steady state process across China?s provinces.Highly significant human and real capital identifies the importance of these domestic growth restricting factors. However, other potentially important factors like labor or government expenditures are (surprisingly) insignificant or even negative. Further, in contrast to implications from NEG models indicators for urbanization and agglomeration do not contribute significantly.international integration, regional development, FDI, China

    Automatised matching between two scalar sectors at the one-loop level

    Get PDF
    Nowadays, one needs to consider seriously the possibility that a large separation between the scale of new physics and the electroweak scale exists. Nevertheless, there are still observables in this scenario, in particular the Higgs mass, which are sensitive to the properties of the UV theory. In order to obtain reliable predictions for a model which involves very heavy degrees of freedom, the precise matching to an effective theory is necessary. While this has been so far only studied for a few selected examples, we present an extension of the Mathematica{\tt Mathematica} package SARAH{\tt SARAH} to perform automatically the matching between two scalar sectors at the full one-loop level for general models. We show that we can reproduce all important results for commonly studied models like split- or high-scale supersymmetry. One can now easily go beyond that and study new ideas involving very heavy states, where the effective model can either be just the standard model or an extension of it. Also scenarios with several matching scales can be easily considered. We provide model files for the MSSM with seven different mass hierarchies as well as two high-scale versions of the NMSSM. Moreover, it is explained how new models are implemented

    Short-run and Long-run Dynamics of Growth,Inequality and Poverty in the Developing World

    Get PDF
    Growth, inequality, and poverty are central elements of the development process. However the mutual effects and directions of causality have been, and remain, one of the most controversial issues. After introducing a simple theoretical framework we derive some fundamental relations between growth, inequality and poverty. In the empirical part we test for unit roots and coin- tegration and apply GMM techniques on an error correction model (ECM) to estimate the pairwise short-run and long-run dynamics for income growth and changes in inequality and poverty in a panel of 114 developing countries and six regional subpanels for 1981 to 2005. The results confirm the relations of the theoretical framework; the evidence shows that in nearly all cases the vari- ables exhibit a short-run and long-run relationship. The findings reveal positive bidirectional causality between growth and inequality as well as between in- equality and poverty, and negative bidirectional causality between growth and poverty. Furthermore, the evidence shows that the level of development affects the poverty-reducing effect of growth, and that growth has benefited the poor regions far less. In summary, we show that growth, income distribution and poverty reduction are strongly inter-related, so a sucessful development strat- egy requires effective, country-specific combinations of growth and distribution policies.poverty, inequality, growth and development, panel cointegration, panel causality

    The CP-Violating 2HDM in Light of a Strong First Order Electroweak Phase Transition and Implications for Higgs Pair Production

    Get PDF
    We investigate the strength of the electroweak phase transition (EWPT) within the CP-violating 2-Higgs-Doublet Model (C2HDM). By applying a renormalisation scheme which allows efficient scans of the C2HDM parameter space, we analyse the possibility of a strong first order EWPT required for baryogenesis and study its phenomenological implications for the LHC. Like in the CP-conserving (real) 2HDM (R2HDM) we find that a strong EWPT favours mass gaps between the non-SM-like Higgs bosons. These lead to prominent final states comprised of gauge+Higgs bosons or pairs of Higgs bosons. In contrast to the R2HDM, the CP-mixing of the C2HDM also favours approximately mass degenerate spectra with dominant decays into SM particles. The requirement of a strong EWPT further allows us to distinguish the C2HDM from the R2HDM using the signal strengths of the SM-like Higgs boson. We additionally find that a strong EWPT requires an enhancement of the SM-like trilinear Higgs coupling at next-to-leading order (NLO) by up to a factor of 2.4 compared to the NLO SM coupling, establishing another link between cosmology and collider phenomenology. We provide several C2HDM benchmark scenarios compatible with a strong EWPT and all experimental and theoretical constraints. We include the dominant branching ratios of the non-SM-like Higgs bosons as well as the Higgs pair production cross section of the SM-like Higgs boson for every benchmark point. The pair production cross sections can be substantially enhanced compared to the SM and could be observable at the high-luminosity LHC, allowing access to the trilinear Higgs couplings

    Vector-like Bottom Quarks in Composite Higgs Models

    Get PDF
    Like many other models, Composite Higgs Models feature the existence of heavy vector-like quarks. Mixing effects between the Standard Model fields and the heavy states, which can be quite large in case of the top quark, imply deviations from the SM. In this work we investigate the possibility of heavy bottom partners. We show that they can have a significant impact on electroweak precision observables and the current Higgs results if there is a sizeable mixing with the bottom quark. We explicitly check that the constraints from the measurement of the CKM matrix element VtbV_{tb} are fulfilled, and we test the compatibility with the electroweak precision observables. In particular we evaluate the constraint from the ZZ coupling to left-handed bottom quarks. General formulae have been derived which include the effects of new bottom partners in the loop corrections to this coupling and which can be applied to other models with similar particle content. Furthermore, the constraints from direct searches for heavy states at the LHC and from the Higgs search results have been included in our analysis. The best agreement with all the considered constraints is achieved for medium to large compositeness of the left-handed top and bottom quarks.Comment: additional figures, extended discussion of numerical result
    • 

    corecore