274 research outputs found

    Pseudo-scalar Higgs boson production at N3^3LOA_{\text{A}}+N3^3LL′^\prime

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    We consider the production of a pseudo-scalar particle AA at the LHC, and present accurate theoretical predictions for its inclusive cross section in gluon fusion. The prediction is based on combining fixed-order perturbation theory and all-order threshold resummation. At fixed order we include the exact next-to-next-to-leading order (NNLO) plus an approximate next-to-next-to-next-to-leading order (N3^3LOA_{\rm A}) which is based on the recent computation at this order for the scalar case. We then add threshold resummation at next-to-next-to-next-to leading logarithmic accuracy (N3^3LL′^\prime). Various forms of threshold resummation are considered, differing by the treatment of subleading terms, allowing a robust estimate of the theoretical uncertainties due to missing higher orders. With particular attention to pseudo-scalar masses of 200200 GeV and 750750 GeV, we also observe that perturbative convergence is much improved when resummation is included. Additionally, results obtained with threshold resummation in direct QCD are compared with analogous results as computed in soft-collinear effective theory, which turn out to be in good agreement. We provide precise predictions for pseudo-scalar inclusive cross section at 1313 TeV LHC for a wide range of masses. The results are available through updated versions of the public codes ggHiggs and TROLL.Comment: 14 pages, 7 figures, 1 table. Now includes a more precise assessment of the uncertainty on the approximate N3LO. Final version accepted by EPJ

    MEIOTIC ORIGIN OF TRISOMY IN NEOPLASM: EVIDENCE IN A CASE OF ERYTROLEUKAEMIA

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    Trisomic cells in neoplasms may represent abnormal clones originated from a tissue-confined mosaicism, and arise therefore by a meiotic error. We report on a 16-month-old child with erythroleukaemia (AML-M6), whose marrow karyotype at onset was 48,XX,del(13)(q12q14),del(14)(q22q32),+21,+21. The parental origin of the supernumerary chromosomes 21 was investigated by comparing 10 polymorphic loci scattered along the whole chromosome on the patient's marrow and her parents' leukocytes. Three loci were informative for the presence of three alleles, two of which were of maternal origin; two further loci showed a maternal allele of higher intensity. Lymphocytes and skin fibroblasts showed a normal karyotype, and molecular analysis on leukocytes at remission, buccal smear and urinary sediment cells consistently showed only one maternal allele, whereas neonatal blood from Guthrie spot showed two maternal alleles as in the marrow. An accurate clinical re-evaluation confirmed a normal phenotype. Our results indicate that tetrasomy 21 arose from a marrow clone with trisomy 21 of meiotic origin. To the best of our knowledge, this is the first evidence that supernumerary chromosomes in neoplastic clones may in fact be present due to a meiotic error. This demonstrates that a tissue-confined constitutional mosaicism for a trisomy may indeed represent the first event in multistep carcinogenesis

    Effects of feeding low fishmeal diets with increasing soybean meal levels on growth, gut histology and plasma biochemistry of sea bass

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    The aquaculture industry depends upon the development of sustainable protein sources to replace fishmeal (FM) in aquafeeds and the products derived from soybeans are some of the most studied plant feedstuffs. A key area of investigation for continuing to improve modern aquafeeds includes the evaluation of varying proportions and combinations of plant ingredients to identify mixtures that are more efficiently utilized by the fish. This study investigated the effects of increasing soybean meal (SBM) by replacing a mix of plant ingredients in low FM (20%) diets on growth, blood biochemistry profile and gut histology on European sea bass. Five isonitrogenous and isolipidic experimental diets were formulated: four diets containing increasing SBM levels (0, 10, 20 and 30%; 0SBM, 10SBM, 20SBM and 30SBM, respectively) with a low content of FM (20%) and one control diet (0% SBM; 35% FM). Diets containing SBM brought to comparable performance and protein utilization, while 0SBM had negative impact on feed conversion rate and protein utilization. Blood parameters suggested an optimal nutritional status under all feeding treatments, even though slightly decreased values were reported at increasing dietary SBM. Histology examination did not show any changes indicative of soy-induced enteritis. We can conclude that for European sea bass: (i) different blends of plant protein did not affect feed intake despite the 20% FM dietary level; (ii) the inclusion of SBM maintains optimal growth and feed utilization in low FM diets; (iii) blood biochemistry profile showed a good nutritional status under all feeding regimes; (iv) no evidence of soy-induced enteritis was reported in any group fed low FM diets. For formulation of practical diets in on-growing of European sea bass, SBM up to 30% can be successfully incorporated into feeds containing low FM inclusion

    Research highlights from the 2018 European Respiratory Society International Congress: airway disease.

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    The annual European Respiratory Society (ERS) International Congress (held in Paris in 2018) was once again a platform for discussion of the highest-quality scientific research, cutting-edge techniques and innovative new therapies within the respiratory field. This article discusses only some of the high-quality research studies presented at this year's Congress, with a particular focus on airway diseases including asthma, chronic obstructive pulmonary disease (COPD), bronchiectasis and cough, as presented through Assembly 5 of the ERS (Airway Diseases: Asthma and COPD). The authors establish the key take-home messages of these studies, compare their findings and place them in the context of current understanding

    Higgs boson gluon-fusion production beyond threshold in N3LO QCD

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    In this article, we compute the gluon fusion Higgs boson cross-section at N3LO through the second term in the threshold expansion. This calculation constitutes a major milestone towards the full N3LO cross section. Our result has the best formal accuracy in the threshold expansion currently available, and includes contributions from collinear regions besides subleading corrections from soft and hard regions, as well as certain logarithmically enhanced contributions for general kinematics. We use our results to perform a critical appraisal of the validity of the threshold approximation at N3LO in perturbative QCD

    NLL soft and Coulomb resummation for squark and gluino production at the LHC

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    We present predictions of the total cross sections for pair production of squarks and gluinos at the LHC, including the stop-antistop production process. Our calculation supplements full fixed-order NLO predictions with resummation of threshold logarithms and Coulomb singularities at next-to-leading logarithmic (NLL) accuracy, including bound-state effects. The numerical effect of higher-order Coulomb terms can be as big or larger than that of soft-gluon corrections. For a selection of benchmark points accessible with data from the 2010-2012 LHC runs, resummation leads to an enhancement of the total inclusive squark and gluino production cross section in the 15-30 % range. For individual production processes of gluinos, the corrections can be much larger. The theoretical uncertainty in the prediction of the hard-scattering cross sections is typically reduced to the 10 % level.Comment: 45 pages, 16 Figures, LaTex. v2: published version. Grids with numerical results for the NLL cross sections for squark and gluino production at the 7/8 TeV LHC are included in the submission and are also available at http://omnibus.uni-freiburg.de/~cs1010/susy.htm

    High precision determination of the gluon fusion Higgs boson cross-section at the LHC

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    We present the most precise value for the Higgs boson cross-section in the gluon-fusion production mode at the LHC. Our result is based on a perturbative expansion through N3^3LO in QCD, in an effective theory where the top-quark is assumed to be infinitely heavy, while all other Standard Model quarks are massless. We combine this result with QCD corrections to the cross-section where all finite quark-mass effects are included exactly through NLO. In addition, electroweak corrections and the first corrections in the inverse mass of the top-quark are incorporated at three loops. We also investigate the effects of threshold resummation, both in the traditional QCD framework and following a SCET approach, which resums a class of π2\pi^2 contributions to all orders. We assess the uncertainty of the cross-section from missing higher-order corrections due to both perturbative QCD effects beyond N3^3LO and unknown mixed QCD-electroweak effects. In addition, we determine the sensitivity of the cross-section to the choice of parton distribution function (PDF) sets and to the parametric uncertainty in the strong coupling constant and quark masses. For a Higgs mass of mH=125 GeVm_H = 125~{\rm GeV} and an LHC center-of-mass energy of 13 TeV13~{\rm TeV}, our best prediction for the gluon fusion cross-section is \[ \sigma = 48.58\,{\rm pb} {}^{+2.22\, {\rm pb}\, (+4.56\%)}_{-3.27\, {\rm pb}\, (-6.72\%)} \mbox{ (theory)} \pm 1.56 \,{\rm pb}\, (3.20\%) \mbox{ (PDF+αs\alpha_s)} \

    Les bulles « robustes »:Pourquoi il faut construire des logements en région parisienne

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    « Bulle » ou « pas bulle » ? La question taraude les observateurs et les acteurs du marché immobilier français. Nous examinons dans cet article les éléments empiriques et théoriques qui expliquent la hausse des prix récente et sa résistance aux retournements conjoncturels. En combinant la notion de bulle économique, les arguments de l’économie spatiale et une analyse d’économie politique, nous suggérons que la valorisation importante de l’immobilier en France est le résultat d’une logique rationnelle et conforte les intérêts des acteurs locaux. Dès lors, la forte valorisation peut être considérée comme une « bulle robuste », à même de résister à des chocs importants. Cette bulle organise un transfert intergénérationnel et peut avoir des effets positifs. Elle peut également renforcer la ségrégation spatiale, alimenter les inégalités territoriales et empêcher d’exploiter les économies d’agglomération possibles. L’analyse est détaillée sur la région Ile-de-France où ces phénomènes sont particulièrement marqués
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