920 resultados para Branch and bounds


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We look for minimal chiral sets of fermions beyond the standard model that are anomaly free and, simultaneously, vectorlike particles with respect to color SU(3) and electromagnetic U(1). We then study whether the addition of such particles to the standard model particle content allows for the unification of gauge couplings at a high energy scale, above 5.0 x 10(15) GeV so as to be safely consistent with proton decay bounds. The possibility to have unification at the string scale is also considered. Inspired in grand unified theories, we also search for minimal chiral fermion sets that belong to SU(5) multiplets, restricted to representations up to dimension 50. It is shown that, in various cases, it is possible to achieve gauge unification provided that some of the extra fermions decouple at relatively high intermediate scales.

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We consider the two-Higgs-doublet model as a framework in which to evaluate the viability of scenarios in which the sign of the coupling of the observed Higgs boson to down-type fermions (in particular, b-quark pairs) is opposite to that of the Standard Model (SM), while at the same time all other tree-level couplings are close to the SM values. We show that, whereas such a scenario is consistent with current LHC observations, both future running at the LHC and a future e(+)e(-) linear collider could determine the sign of the Higgs coupling to b-quark pairs. Discrimination is possible for two reasons. First, the interference between the b-quark and the t-quark loop contributions to the ggh coupling changes sign. Second, the charged-Higgs loop contribution to the gamma gamma h coupling is large and fairly constant up to the largest charged-Higgs mass allowed by tree-level unitarity bounds when the b-quark Yukawa coupling has the opposite sign from that of the SM (the change in sign of the interference terms between the b-quark loop and the W and t loops having negligible impact).

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It has been pointed out recently that current experiments still allow for a two Higgs doublet model where the hbb¯ coupling (kDmb/v) is negative; a sign opposite to that of the Standard Model. Due to the importance of delayed decoupling in the hH+H− coupling, h→γγ improved measurements will have a strong impact on this issue. For the same reason, measurements or even bounds on h→Zγ are potentially interesting. In this article, we revisit this problem, highlighting the crucial importance of h→VV, which can be understood with simple arguments. We show that the impacts on kD<0 models of both h→bb¯ and h→τ+τ− are very sensitive to input values for the gluon fusion production mechanism; in contrast, h→γγ and h→Zγ are not. We also inquire if the search for h→Zγ and its interplay with h→γγ will impact the sign of the hbb¯ coupling. Finally, we study these issues in the context of the flipped two Higgs doublet model.

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Paper developed for the unit “Innovation Economics and Management” of the PhD programme in Technology Assessment at the Universidade Nova de Lisboa in 2009-10 under the supervision of Prof. Maria Luísa Ferreira

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Abdominal angiostrongyliasis is a parasitic disease caused by Angiostrongylus costaricensis, a metastrongylid nematode with wide geographic distribution, occurring from the United States to Argentina. In Brazil, the disease has been reported from the States of Rio Grande do Sul, Santa Catarina, Paraná, São Paulo, Federal District of Brasilia and Minas Gerais. We report here a case of abdominal angiostrongyliasis in a 9-year-old girl, from Itatiba, State of Espirito Santo, Brazil, submitted to exploratory laparotomy for acute abdomen. Extensive inflammatory lesions of terminal ileum and cecum, with perforations of the first, were present, and ileocecal resection was performed. The pathological picture was characterized by transmural inflammatory granulomatous reaction, extensive eosinophilic infiltration, eosinophilic vasculitis and the presence of worms within a mesenteric artery branch, with histological features of metastrongylid nematodes. This case report contributes to a better knowledge of the geographic distribution of this parasite in Brazil, suggesting that abdominal angiostrongyliasis may represent a disease of medical importance, more than a rarity of academic interest.

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Based on a poster submitted to CONCORD 2011 - Conference on Corporate R&D: The dynamics of Europe's industrial structure and the growth of innovative firms, Sevilla, IPTS, 6 Out. 2011, Seville, http://www.eventisimo.com/concord2011/recibido.html

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We prove that the stable holonomies of a proper codimension 1 attractor Λ, for a Cr diffeomorphism f of a surface, are not C1+θ for θ greater than the Hausdorff dimension of the stable leaves of f intersected with Λ. To prove this result we show that there are no diffeomorphisms of surfaces, with a proper codimension 1 attractor, that are affine on a neighbourhood of the attractor and have affine stable holonomies on the attractor.

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3rd Workshop on High-performance and Real-time Embedded Systems (HIRES 2015). 21, Jan, 2015. Amsterdam, Netherlands.

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RTUWO Advances in Wireless and Optical Communications 2015 (RTUWO 2015). 5-6 Nov Riga, Latvia.

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During the last years, several studies have been made aiming to assess the out-of-plane seismic response of unreinforced stone masonry structures. This fact led to the development of a wide variety of models and approaches, ranging from simple kinematic based analytical models up to complex numerical simulations. Nevertheless, for the sake of simplicity, the out-of-plane seismic response of a masonry wall pier may be obtained by means of a simple single-degree-of-freedom system while still providing good results. In fact, despite the assumptions associated with such a simple formulation, it is also true that the epistemic uncertainty inherent with the selection of appropriate input parameters in more complex models may render them truly ineffective. In this framework, this paper focuses on the study of the out-of-plane bending of unreinforced stone masonry walls (cantilevers) by proposing a simplified analytical approach based on the construction of a linearized four-branch model, which is used to characterize the linear and nonlinear response of such structural elements through an overturning moment-rotation relationship. The formulation of the four-branch model is presented and described in detail and the meaningful parameters used for its construction are obtained from a set of experimental laboratory tests performed on six full-scale unreinforced regular sacco stone masonry specimens. Moreover, a parametric analysis aiming to evaluate the effect of these parameters’ variation on the final configuration of the model is presented and critically discussed. Finally, the results obtained from the application of the developed four-branch model on real unreinforced regular sacco stone masonry walls are thoroughly analysed and the main conclusions obtained from its application are summarized.

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By controlling the transmission of Chagas disease, the challenge of providing assistance to millions of infected patients that reach old age arises. In this study, the socioeconomic, demographic and comorbidity records of all elderly chagasic patients followed at the Pharmaceutical Care Service of the Chagas Disease Research Laboratory were assessed. The information related to the clinical form of the disease was obtained from medical records provided by the Walter Cantídio University Hospital. The profile of the studied population was: women (50.5%); mean age of 67 years; retired (54.6%); married (51.6 %); high illiteracy rate (40.2%); and family income equal to the minimum wage (51.5%). The predominant clinical forms of Chagas disease were cardiac (65.3%) and indeterminate (14.7%). The main electrocardiographic changes were the right bundle branch block (41.0%), associated or not with the anterosuperior left bundle branch block (27.4%). The average number of comorbidities per patient was 2.23 ± 1.54, with systemic arterial hypertension being the main one found (67.0%). It was found that the elderly comprise a vulnerable group of patients that associate aging with cardiac and/or digestive disorders resulting from the evolution of Chagas disease and other comorbidities, which requires special attention from health services to ensure more appropriate medical and social care.

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Ophthalmoplegic migraine (OM) is a childhood disorder of uncertain etiology manifesting recurrent unilateral headache associated with a transitory oculomotor (usually IIIrd nerve) palsy. Recent publications emphasize the finding on MRI of contrast enhancement in the IIIrd nerve suggesting that OM may be a recurrent inflammatory neuropathy. We report the case of a 7-year-old boy with typical symptoms of this disorder. Angio MR and Angio CT revealed the presence of an infundibular dilatation of a perforating branch of the posterior cerebral artery adjacent to the symptomatic IIIrd nerve. We speculate that this and perhaps other cases of OM may have a different pathophysiology related to compression of the IIIrd nerve by an adjacent vascular structure that could activate the trigeminovascular system and produce migrainous pain.

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INTRODUCTION: Deforestation, uncontrolled forest, human population migration from endemic areas, and the large number of reservoirs and wild vectors naturally infected by Trypanosoma cruzi promote the endemicity of Chagas disease in the Amazon region. METHODS: We conducted an initial serological survey (ELISA) in a sample of 1,263 persons; 1,095 (86.7%) were natives of the State of Amazonas, 666 (52.7%) were male, and 948 (75.1%) were over 20 years old. Serum samples that were found to be reactive, indeterminate, or inconclusive by indirect immunofluorescence (IFI) or positive with low titer by IFA were tested by Western blot (WB). Serologically confirmed patients (WB) were evaluated in terms of epidemiological, clinical, ECG, and echocardiography characteristics. RESULTS: Fifteen patients had serologically confirmed T. cruzi infection, and 12 of them were autochthonous to the state of Amazonas, for an overall seroprevalence of 1.2% and 0.9% for the state of Amazonas. Five of the 15 cases were males, and the average age was 47 years old; most were farmers with low education. One patient who was not autochthonous, having originated from Alagoas, showed right bundle branch block, bundle branch block, and anterosuperior left ventricular systolic dysfunction with an ejection fraction of 54%. CONCLUSIONS: The results of this study ratify the importance of monitoring CD cases in Amazonia, particularly in the state of Amazonas.

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Bioethics, as a branch of philosophy that focuses on questions relative to health and human life, is closely tied to the idea of justice and equality. As such, in understanding the concept of equality in its original sense, that is, in associating it to the idea to treat "unequals" (those who are unequal or different, in terms of conditions or circumstances) unequally (differentially), in proportion to their inequalities (differences), we see that the so-called "one-and-only waiting list" for transplants established in law no. 9.434/97, ends up not addressing the concept of equality and justice, bearing upon bioethics, even when considering the objective criteria of precedence established in regulation no. 9.4347/98, Thus, the organizing of transplants on a one-and-only waiting list, with a few exceptions that are weakly applicable, without a case by case technical and grounded analysis, according to each particular necessity, ends up institutionalizing inequalities, condemning patients to happenstance and, consequently, departs from the ratio legis, which aims at seeking the greatest application of justice in regards to organ transplants. We conclude, therefore, that from an analysis of the legislation and of the principles of bioethics and justice, there is a need for the creation of a collegiate of medical experts, that, based on medical criteria and done in a well established manner, can analyze each case to be included on the waiting list, deferentially and according to the necessity; thus, precluding that people in special circumstances be treated equal to people in normal circumstances.

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A search for pair production of vector-like quarks, both up-type (T) and down-type (B), as well as for four-top-quark production, is presented. The search is based on pp collisions at s√=8 TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 20.3 fb−1. Data are analysed in the lepton-plus-jets final state, characterised by an isolated electron or muon with high transverse momentum, large missing transverse momentum and multiple jets. Dedicated analyses are performed targeting three cases: a T quark with significant branching ratio to a W boson and a b-quark (TT¯→Wb+X), and both a T quark and a B quark with significant branching ratio to a Higgs boson and a third-generation quark (TT¯→Ht+X and BB¯→Hb+X respectively). No significant excess of events above the Standard Model expectation is observed, and 95% CL lower limits are derived on the masses of the vector-like T and B quarks under several branching ratio hypotheses assuming contributions from T→Wb, Zt, Ht and B→Wt, Zb, Hb decays. The 95% CL observed lower limits on the T quark mass range between 715 GeV and 950 GeV for all possible values of the branching ratios into the three decay modes, and are the most stringent constraints to date. Additionally, the most restrictive upper bounds on four-top-quark production are set in a number of new physics scenarios.