4,612 research outputs found

    Comment on ``Inflation and flat directions in modular invariant superstring effective theories''

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    The inflation model of Gaillard, Lyth and Murayama is revisited, with a systematic scan of the parameter space for dilaton stabilization during inflation.Comment: 7 pages, 2 figure

    Gaugino Condensation with S-Duality and Field-Theoretical Threshold Corrections

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    We study gaugino condensation in the presence of an intermediate mass scale in the hidden sector. S-duality is imposed as an approximate symmetry of the effective supergravity theory. Furthermore, we include in the K\"ahler potential the renormalization of the gauge coupling and the one-loop threshold corrections at the intermediate scale. It is shown that confinement is indeed achieved. Furthermore, a new running behaviour of the dilaton arises which we attribute to S-duality. We also discuss the effects of the intermediate scale, and possible phenomenological implications of this model.Comment: 19 pages, LaTeX, 3 postscript figures include

    Chirurgie hépatique mineure par laparoscopie en ambulatoire : étude rétrospective observationnelle

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    RésuméAu cours de la dernière décennie, la chirurgie hépatique laparoscopique (CHL) a connu un essor dans le monde entier. Parallèlement, la chirurgie ambulatoire a été développée afin d’améliorer le confort des patients et de réduire les dépenses de santé. L’objectif de cette étude est de rapporter notre expérience préliminaire de la CHL en ambulatoire. Entre 1999 et 2014, 172 patients ont été opérés dans notre institution d’une CHL, incluant 151 résections hépatiques et 21 fenestrations de kystes hépatiques. Tous les patients consécutifs, hautement sélectionnés, opérés d’une CHL en ambulatoire ont été inclus. Vingt patients ont été opérés d’une CHL en ambulatoire. Les indications étaient des kystes hépatiques dans 10 cas, un angiome hépatique dans 3 cas, une hyperplasie nodulaire focale dans 3 cas, et une métastase hépatique de cancer colorectal dans 4 cas. La durée opératoire médiane était de 92minutes (dispersion : 50–240minutes). La perte sanguine médiane était de 35mL (dispersion : 20–150mL). Il n’a pas été observé de complication ni de réhospitalisation. Tous les patients étaient hospitalisés en postopératoire dans notre unité de chirurgie ambulatoire, et ont pu quitter l’établissement 5 à 7heures après la fin de la chirurgie. Le score médian de douleur postopératoire à la sortie était de 3 (échelle visuelle analogique à 10 niveaux ; dispersion : 0–4). Le score médian de qualité de vie à la première consultation postopératoire était de 8 (dispersion : 6–10), et le score médian de satisfaction esthétique était de 8 (dispersion : 7–10). Cette série montre que la CHL ambulatoire est faisable et sûre et chez des patients sélectionnés pour des interventions mineures.SummaryOver the last decade, laparoscopic hepatic surgery (LHS) has been increasingly performed throughout the world. Meanwhile, ambulatory surgery has been developed and implemented with the aims of improving patient satisfaction and reducing health care costs. The objective of this study was to report our preliminary experience with ambulatory minimally-invasive LHS. Between 1999 and 2014, 172 patients underwent LHS at our institution, including 151 liver resections and 21 fenestrations of hepatic cysts. The consecutive series of highly selected patients who underwent ambulatory LHS were included in this study. Twenty patients underwent ambulatory LHS. The indications were liver cysts in 10 cases, liver angioma in 3 cases, focal nodular hyperplasia in 3 cases, and colorectal hepatic metastasis in 4 cases. The median operative time was 92minutes (range: 50–240minutes). The median blood loss was 35mL (range: 20–150mL). There were no postoperative complications or re-hospitalizations. All patients were hospitalized after surgery in our ambulatory surgery unit, and were discharged 5–7hours after surgery. The median postoperative pain score at the time of discharge was 3 (visual analogue scale 0–10; range: 0–4). The median quality-of-life score at the first postoperative visit was 8 (range: 6–10) and the median cosmetic satisfaction score was 8 (range: 7–10). This series shows that, in selected patients, ambulatory LHS is feasible and safe for minor hepatic procedures

    Supergravity Radiative Effects on Soft Terms and the ÎĽ\mu Term

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    We compute quadratically divergent supergravity one-loop effects on soft supersymmetry-breaking parameters and the ÎĽ\mu term in generic hidden sector supergravity models. These effects can significantly modify the matching condition for soft parameters at the Planck scale and also provide several new sources of the ÎĽ\mu term which are naturally of order the weak scale. We also discuss some phenomenological implications of these effects, particularly the violation of the scalar mass universality which may lead to dangerous FCNC phenomena, and apply the results to superstring effective supergravity models.Comment: 12 pages, REVTEX. One reference is adde

    Inflation and flat directions in modular invariant superstring effective theories

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    The potential during inflation must be very flat in, at least, the direction of the inflaton. In renormalizable global supersymmetry, flat directions are ubiquitous, but they are not preserved in a generic supergravity theory. It is known that at least some of them are preserved in no-scale supergravity, and simple generalizations of it. We here study a more realistic generalization, based on string-derived supergravity, using the linear supermultiplet formalism for the dilaton. We consider a general class of hybrid inflation models, where a Fayet-Illiopoulos DD term drives some fields to large values. The potential is dominated by the FF term, but flatness is preserved in some directions. This allows inflation, with the dilaton stabilized in its domain of attraction, and some moduli stabilized at their vacuum values. Another modulus may be the inflaton.Comment: 19 pages, REVTEX, further typos, refs fixe

    Comparative mapping of human chromosome 13 genes in the pig shows a similar gene arrangement

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    Previous comparative mapping between the human and pig genomes suggested complete conservation of human chromosome 13 (HSA13) to pig chromosome 11 (SSC11). The objectives of this study were comparative gene mapping of pig homologs of HSA13 genes and an examination of gene order within this conserved synteny group by physical assignment of each locus. A detailed HSA13 to SSC11 comparison was chosen since the comparative gene map is not well developed for these chromosomes and a rearranged gene order within conserved synteny groups was observed from the comparison between human chromosome 13 and bovine chromosome 12. Pig sequence tagged sites (STSs) for six HSA13 genes were developed and physically mapped using a somatic cell hybrid panel (SCHP) to SSC11 with 85–100% concordance. Fluorescent in situ hybridization (FISH) mapping also was applied to determine the gene order within each subchromosomal region. Results from this study increase the comparative information available on SSC11 and suggest the same gene order among examined loci on SSC11 and HSA13

    Comparative mapping of human chromosome 3 genes in the pig shows different gene order

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    A comparative map of human chromosome 3 (HSA3) and pig chromosome 13 (SSC13) was constructed using physically assigned pig sequence tagged sites (STSs). Pig STS representing 11 HSA3 genes were developed and 10 pig STS were regionally mapped using a somatic cell hybrid panel (SCHP) to SSC13 with 80–100% concordance. Large-insert probes were obtained by screening a YAC library with primers for each STS. YACs were identified for DRD3, GAP43, PIT1, SI, and SST for fluorescent in situ hybridization (FISH) mapping. Single gene and bicolor FISH with each pairwise combination was used to further define gene order on SSC13. These data confrim chromosome painting results that showed HSA3 probes hybridize to a major portion of pig chromosome 13 and demonstrate extensive gene rearrangements within this conserved synteny group

    Making Ends Meet: String Unification and Low-Energy Data

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    A long-standing problem in string phenomenology has been the fact that the string unification scale disagrees with the GUT scale obtained by extrapolating low-energy data within the framework of the minimal supersymmetric standard model (MSSM). In this paper we examine several effects that may modify the minimal string predictions and thereby bring string-scale unification into agreement with low-energy data. These include heavy string threshold corrections, non-standard hypercharge normalizations, light SUSY thresholds, intermediate gauge structure, and thresholds arising from extra matter beyond the MSSM. We explicitly evaluate these contributions within a variety of realistic free-fermionic string models, including the flipped SU(5), SO(6) x SO(4), and various SU(3) x SU(2) x U(1) models, and find that most of these sources do not substantially alter the minimal string predictions. Indeed, we find that the only way to reconcile string unification with low-energy data is through certain types of extra matter. Remarkably, however, many of the realistic string models contain precisely this required matter in their low-energy spectra.Comment: 10 pages, standard LaTeX, 1 figure (Encapsulated PostScript), version published in Phys. Rev. Lett. 75 (1995) 264

    Inflation and Kahler Stabilization of the Dilaton

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    The problems of attempting inflationary model-building in a theory containing a dilaton are explained. In particular, I study the shape of the dilaton potential today and during inflation, based on a weakly-coupled heterotic string model where corrections to the Kahler potential are assumed to be responsible for dilaton stabilization. Although no specific model-building is attempted, if the inflationary energy density is related to the scale of gaugino condensation, then the dilaton may be stabilized close enough to today's value that there is no significant change in the GUT scale coupling. This can occur in a very wide range of models, and helps to provide some justification for the standard predictions of the spectral index. I explain how this result can ultimately be traced to the supersymmetry structure of the theory.Comment: 12 pages, submitted to PR
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