311 research outputs found

    Minimal Flavour Violation with hierarchical squark masses

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    In a supersymmetric model with hierarchical squark masses we analyze a pattern of flavour symmetry breaking centered on the special role of the top Yukawa coupling and, by extension, of the full Yukawa couplings for the up-type quarks. For sufficiently heavy squarks of the first and second generation this leads to effective Minimal Flavour Violation of the Flavour Changing Neutral Current amplitudes. For this to happen we determine the bounds on the masses of the heavy squarks with QCD corrections taken into account, properly including previously neglected effects. We believe that the view presented in this paper altogether strengthens the case for hierarchical sfermions.Comment: 13 pages, 1 figure. v2: an equation correcte

    CP Violation in Supersymmetry with Effective Minimal Flavour Violation

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    We analyze CP violation in supersymmetry with Effective Minimal Flavour Violation, as recently proposed in arXiv:1011.0730. Unlike the case of standard Minimal Flavour Violation, we show that all the phases allowed by the flavour symmetry can be sizable without violating existing Electric Dipole Moment constraints, thus solving the SUSY CP problem. The EDMs at one and two loops are precisely analyzed as well as their correlations with the expected CP asymmetries in B physics.Comment: 22 pages, 7 figures. v2: Discussion in section 2 extended, conclusions unchanged. Matches published versio

    Ecological Implications of Extreme Events: Footprints of the 2010 Earthquake along the Chilean Coast

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    Deciphering ecological effects of major catastrophic events such as earthquakes, tsunamis, volcanic eruptions, storms and fires, requires rapid interdisciplinary efforts often hampered by a lack of pre-event data. Using results of intertidal surveys conducted shortly before and immediately after Chile's 2010 Mw 8.8 earthquake along the entire rupture zone (ca. 34–38°S), we provide the first quantification of earthquake and tsunami effects on sandy beach ecosystems. Our study incorporated anthropogenic coastal development as a key design factor. Ecological responses of beach ecosystems were strongly affected by the magnitude of land-level change. Subsidence along the northern rupture segment combined with tsunami-associated disturbance and drowned beaches. In contrast, along the co-seismically uplifted southern rupture, beaches widened and flattened increasing habitat availability. Post-event changes in abundance and distribution of mobile intertidal invertebrates were not uniform, varying with land-level change, tsunami height and coastal development. On beaches where subsidence occurred, intertidal zones and their associated species disappeared. On some beaches, uplift of rocky sub-tidal substrate eliminated low intertidal sand beach habitat for ecologically important species. On others, unexpected interactions of uplift with man-made coastal armouring included restoration of upper and mid-intertidal habitat seaward of armouring followed by rapid colonization of mobile crustaceans typical of these zones formerly excluded by constraints imposed by the armouring structures. Responses of coastal ecosystems to major earthquakes appear to vary strongly with land-level change, the mobility of the biota and shore type. Our results show that interactions of extreme events with human-altered shorelines can produce surprising ecological outcomes, and suggest these complex responses to landscape alteration can leave lasting footprints in coastal ecosystems

    Ward Identities, B-> \rho Form Factors and |V_ub|

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    The exclusive FCNC beauty semileptonic decay B-> \rho is studied using Ward identities in a general vector meson dominance framework, predicting vector meson couplings involved. The long distance contributions are discussed which results to obtain form factors and |V_ub|. A detailed comparison is given with other approaches.Comment: 30 pages+four postscript figures, an Appendix adde

    Composite GUTs: models and expectations at the LHC

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    We investigate grand unified theories (GUTs) in scenarios where electroweak (EW) symmetry breaking is triggered by a light composite Higgs, arising as a Nambu-Goldstone boson from a strongly interacting sector. The evolution of the standard model (SM) gauge couplings can be predicted at leading order, if the global symmetry of the composite sector is a simple group G that contains the SM gauge group. It was noticed that, if the right-handed top quark is also composite, precision gauge unification can be achieved. We build minimal consistent models for a composite sector with these properties, thus demonstrating how composite GUTs may represent an alternative to supersymmetric GUTs. Taking into account the new contributions to the EW precision parameters, we compute the Higgs effective potential and prove that it realizes consistently EW symmetry breaking with little fine-tuning. The G group structure and the requirement of proton stability determine the nature of the light composite states accompanying the Higgs and the top quark: a coloured triplet scalar and several vector-like fermions with exotic quantum numbers. We analyse the signatures of these composite partners at hadron colliders: distinctive final states contain multiple top and bottom quarks, either alone or accompanied by a heavy stable charged particle, or by missing transverse energy.Comment: 55 pages, 13 figures, final version to be published in JHE

    A Primer on the Acute Management of Intravenous Extravasation Injuries for the Plastic Surgeon

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    Intravenous therapy is a common practice among many specialties. Intravenous therapy extravasation is a potential complication to such therapy. Hospitals without a dedicated wound care team trained in these interventions will often default to plastic surgical consultation, making an understanding of available interventions essential to the initial evaluation and management of these injuries. The goal of this article was to provide plastic surgeons and health care providers with a general overview of the acute management of intravenous infiltration and extravasation injuries. Though the decision for surgical versus nonsurgical management is often a clear one for plastic surgeons, local interventions, and therapies are often indicated and under-utilized in the immediate postinfiltration period. Thorough knowledge of these interventions should be a basic requirement in the armamentarium of plastic surgery consultants

    European randomized study of prostate cancer screening: first-year results of the Finnish trial

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    Approximately 20 000 men 55–67 years of age from two areas in Finland were identified from the Population Registry and randomized either to the screening arm (1/3) or the control arm (2/3) of a prostate cancer screening trial. In the first round, the participation rate in the screening arm was 69%. Of the 5053 screened participants, 428 (8.5%) had a serum prostate-specific antigen (PSA) concentration of 4.0 ng/ml or higher, and diagnostic examinations were performed on 399 of them. A total of 106 cancers were detected among them corresponding to a positive predictive value of 27%, which is comparable with mammography screening for breast cancer. The prostate cancer detection rate based on a serum PSA concentration of 4.0 ng ml−1 or higher was 2.1%. Approximately nine out of ten screen-detected prostate cancers were localized (85% clinical stage T1–T2) and well or moderately differentiated (42% World Health Organization (WHO) grade I and 50% grade II), which suggests a higher proportion of curable cancers compared with cases detected by other means. © 1999 Cancer Research Campaig

    One Hundred Priority Questions for the Development of Sustainable Food Systems in Sub-Saharan Africa

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    Sub-Saharan Africa is facing an expected doubling of human population and tripling of food demand over the next quarter century, posing a range of severe environmental, political, and socio-economic challenges. In some cases, key Sustainable Development Goals (SDGs) are in direct conflict, raising difficult policy and funding decisions, particularly in relation to trade-offs between food production, social inequality, and ecosystem health. In this study, we used a horizon-scanning approach to identify 100 practical or research-focused questions that, if answered, would have the greatest positive impact on addressing these trade-offs and ensuring future productivity and resilience of food-production systems across sub-Saharan Africa. Through direct canvassing of opinions, we obtained 1339 questions from 331 experts based in 55 countries. We then used online voting and participatory workshops to produce a final list of 100 questions divided into 12 thematic sections spanning topics from gender inequality to technological adoption and climate change. Using data on the background of respondents, we show that perspectives and priorities can vary, but they are largely consistent across different professional and geographical contexts. We hope these questions provide a template for establishing new research directions and prioritising funding decisions in sub-Saharan Africa

    Minimal Flavour Violation with Strong Higgs Dynamics

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    We develop a variant of the Minimal Flavour Violation ansatz for the case of a strongly interacting heavy-Higgs boson sector. The tower of effective operators differs from that for a Higgs system in the linear regime, and the new operators obtained at leading order include a CP-odd one. We investigate the impact of these operators on Delta F=1 and Delta F=2 observables, demonstrating that the non-linear scenario may have an interesting impact on the anomalies in present data.Comment: 35 pages, 4 figures; version accepted for publication on JHE
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