94 research outputs found

    QCD Corrections in Supersymmetric Theories

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    I discuss the effects of QCD radiative corrections in Supersymmetric theories. After summarizing the SUSY--QCD lagrangian in the Minimal Supersymmetric extension of the Standard Model, I will discuss the new features introduced by SUSY, and the main complications compared to standard QCD corrections. I will then discuss a few examples of QCD calculations in SUSY theories, for standard processes and for processes involving SUSY particles including the extended Higgs sector. [Talk given at "QCD 97", Montpellier 3-9 July 1997.]Comment: 5 pages, no figures, needs espcrc2.st

    Towards Higgs boson production in gluon fusion to NNLO in the MSSM

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    We consider the Higgs boson production in the gluon-fusion channel to next-to-next-to-leading order within the Minimal Supersymmetric Standard Model. In particular, we present analytical results for the matching coefficient of the effective theory and study its influence on the total production cross section in the limit where the masses of all MSSM particles coincide. For supersymmetric masses below 500 GeV it is possible to find parameters leading to a significant enhancement of the Standard Model cross section, the KK-factors, however, change only marginally.Comment: 20 pages; v2: modification of discussion of numerical effect, version to appear in EPJC; v3: eq.(18) corrected, minor correction

    Preclinical activity of melflufen (J1) in ovarian cancer

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    Ovarian cancer carries a significant mortality. Since symptoms tend to be minimal, the disease is often diagnosed when peritoneal metastases are already present. The standard of care in advanced ovarian cancer consists of platinum-based chemotherapy combined with cytoreductive surgery. Unfortunately, even after optimal cytoreduction and adjuvant chemotherapy, most patients with stage III disease will develop a recurrence. Intraperitoneal administration of chemotherapy is an alternative treatment for patients with localized disease. The pharmacological and physiochemical properties of melflufen, a peptidase potentiated alkylator, raised the hypothesis that this drug could be useful in ovarian cancer and particularily against peritoneal carcinomatosis. In this study the preclinical effects of melflufen were investigated in different ovarian cancer models. Melflufen was active against ovarian cancer cell lines, primary cultures of patient-derived ovarian cancer cells, and inhibited the growth of subcutaneous A2780 ovarian cancer xenografts alone and when combined with gemcitabine or liposomal doxorubicin when administered intravenously. In addition, an intra- and subperitoneal xenograft model showed activity of intraperitoneal administered melflufen for peritoneal carcinomatosis, with minimal side effects and modest systemic exposure. In conclusion, results from this study support further investigations of melflufen for the treatment of peritoneal carcinomatosis from ovarian cancer, both for intravenous and intraperitoneal administration

    Higgs Boson Theory and Phenomenology

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    Precision electroweak data presently favors a weakly-coupled Higgs sector as the mechanism responsible for electroweak symmetry breaking. Low-energy supersymmetry provides a natural framework for weakly-coupled elementary scalars. In this review, we summarize the theoretical properties of the Standard Model (SM) Higgs boson and the Higgs sector of the minimal supersymmetric extension of the Standard Model (MSSM). We then survey the phenomenology of the SM and MSSM Higgs bosons at the Tevatron, LHC and a future e+e- linear collider. We focus on the Higgs discovery potential of present and future colliders and stress the importance of precision measurements of Higgs boson properties.Comment: 90 pages, 31 figures. Revised version. To be published in Progress in Particle and Nuclear Physics. This paper with higher resolution figures can be found at http://scipp.ucsc.edu/~haber/higgsreview/higgsrev.p

    Recent Progress in Perturbative Quantum Field Theory

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    In this talk, the recent breakthrough in two-loop perturbative calculations is reviewed, with emphasis on the applications to phenomenological studies. The recent precision measurement of the anomalous magnetic moment of the muon by the Brookhaven g-2 collaboration is also used as an illustrative example of the importance of Standard Model precision perturbative calculations to further our understanding of Nature.Comment: Plenary talk given at ICHEP02, July 24-31, 2002, Amsterda

    TESLA Technical Design Report Part III: Physics at an e+e- Linear Collider

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    The TESLA Technical Design Report Part III: Physics at an e+e- Linear ColliderComment: 192 pages, 131 figures. Some figures have reduced quality. Full quality figures can be obtained from http://tesla.desy.de/tdr. Editors - R.-D. Heuer, D.J. Miller, F. Richard, P.M. Zerwa

    Physics searches at the LHC

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    With the LHC up and running, the focus of experimental and theoretical high energy physics will soon turn to an interpretation of LHC data in terms of the physics of electroweak symmetry breaking and the TeV scale. We present here a broad review of models for new TeV-scale physics and their LHC signatures. In addition, we discuss possible new physics signatures and describe how they can be linked to specific models of physics beyond the Standard Model. Finally, we illustrate how the LHC era could culminate in a detailed understanding of the underlying principles of TeV-scale physics.Comment: 184 pages, 55 figures, 14 tables, hundreds of references; scientific feedback is welcome and encouraged. v2: text, references and Overview Table added; feedback still welcom

    Supersymmetric next-to-next-to-leading order corrections to Higgs boson production in gluon fusion

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    We compute the total cross section for the production of a light CP even Higgs boson within the framework of supersymmetric QCD up to next-to-next-to-leading order. Technical subtleties in connection to the evaluation of three-loop Feynman integrals with many mass scales are discussed in detail and explicit results for the counterterms of the evanescent couplings are provided. The new results are applied to several phenomenological scenarios which are in accordance with the recent discovery at the LHC. In a large part of the still allowed parameter space the KK factor of the supersymmetric theory is close to the one of the Standard Model. However, for the case where one of the top squarks is light, a deviation of more than 5% in the next-to-next-to-leading order prediction of the cross section can be observed where at the same time the predicted Higgs boson mass has a value of about 125 GeV.Comment: 37 page

    Is sleep disruption a risk factor for Alzheimer’s disease?

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    Sleep disturbances are routinely encountered in Alzheimer’s disease (AD) and affect about 25–40% of patients in the mild-to-moderate stages of the disease. In many, sleep pathology may represent a symptom of the underlying neurodegeneration. However, a history of sleep disruption occurring years prior to onset of cognitive symptoms could represent a potential risk factor for AD. The aim of the present narrative review was to evaluate current evidence linking sleep disturbances with AD development and to understand the mechanisms that may contribute to this. Although the mechanisms by which poor sleep may contribute to AD genesis is not fully understood, emerging evidence linking disturbances in the sleep wake cycle with Aβ deposition is shedding light on the relationship between sleep pathology and the subsequent development of AD. Aβ burden appears to be enhanced by sleep-wake cycle disruptions and is suspected as being an important mechanism by which sleep disruptions contribute in AD development. Other mechanisms triggered by sleep disruption may also be involved in AD development, such as brain hypoxia, oxidative stress, circadian activity rhythms disturbances, overexpression of orexins, and blood-brain barrier impairment. Further understanding of the link between sleep disturbances and future development of AD is still needed before sleep disturbances are clearly marked as a preventable risk factor for AD. In these circumstances, early lifestyle interventions to help increase the quantity and quality of sleep may have a favorable outcome on decreasing the incidence of AD and this needs to be investigated further

    Transcriptomic epidemiology of smoking: the effect of smoking on gene expression in lymphocytes

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    <p>Abstract</p> <p>Background</p> <p>This investigation offers insights into system-wide pathological processes induced in response to cigarette smoke exposure by determining its influences at the gene expression level.</p> <p>Methods</p> <p>We obtained genome-wide quantitative transcriptional profiles from 1,240 individuals from the San Antonio Family Heart Study, including 297 current smokers. Using lymphocyte samples, we identified 20,413 transcripts with significantly detectable expression levels, including both known and predicted genes. Correlation between smoking and gene expression levels was determined using a regression model that allows for residual genetic effects.</p> <p>Results</p> <p>With a conservative false-discovery rate of 5% we identified 323 unique genes (342 transcripts) whose expression levels were significantly correlated with smoking behavior. These genes showed significant over-representation within a range of functional categories that correspond well with known smoking-related pathologies, including immune response, cell death, cancer, natural killer cell signaling and xenobiotic metabolism.</p> <p>Conclusions</p> <p>Our results indicate that not only individual genes but entire networks of gene interaction are influenced by cigarette smoking. This is the largest <it>in vivo </it>transcriptomic epidemiological study of smoking to date and reveals the significant and comprehensive influence of cigarette smoke, as an environmental variable, on the expression of genes. The central importance of this manuscript is to provide a summary of the relationships between gene expression and smoking in this exceptionally large cross-sectional data set.</p
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