1,261 research outputs found

    Mixing angle of doubly heavy baryons in QCD

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    We calculate the mixing angles between the spin--1/2, Ξbc\Xi_{bc}--Ξbc\Xi^\prime_{bc} and Ωbc\Omega_{bc}--Ωbc\Omega^\prime_{bc} states of doubly heavy baryons within the QCD sum rules method. It is found that the mixing angles are large and have the values φΞbc=160±50\varphi_{\Xi_{bc}} = 16^0 \pm 5^0 and φΩbc=180±60\varphi_{\Omega_{bc}} = 18^0 \pm 6^0, respectively. The mixing angles are slightly smaller compared to the predictions of the non--relativistic quark model, φΞbc=25.50\varphi_{\Xi_{bc}} = 25.5^0 and φΩbc=25.90\varphi_{\Omega_{bc}} = 25.9^0.Comment: 6 Page

    Margaret Fuller's Rome and the problem of provincial American democracy

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    Margaret Fuller's visit to Italy as a correspondent for the New York Tribune at the time of the 1848 revolutions gave her a unique perspective on them, not only as a feminist intellectual but also as a commentator on the American relationship with revolutionary Europe. In her Tribune writings she addressed issues at once more partisan and more global than those she had covered inside the United States, including the political condition of Italy as a subject state under Austrian imperial control, and as an object of ridicule by many American observers, and the condition of American slavery. Italian peoples and slaves, in her mind, were, like women, oppressed by a transatlantic patriarchy whose prejudices allowed only for white males to enjoy political independence. Fuller called for American support for the Roman republic, but her sympathies did not reflect the thrust of American opinion. Many Americans did not believe Italians were capable of maintaining republican self-government, which was different, they alleged, from their own version, part of the inheritance of the American Revolution. That heritage conferred a unique American revolutionary 'exceptionalism'. For these Americans, the 1848 revolutions provided evidence that Europe was impulsive, reactionary and flawed; they saw in them confirmation of the superiority of American race relations and democratic society. After her death in 1850, the American Civil War would confirm Fuller's implicit sense that the United States and Europe were more alike than many Americans of her generation believed or realized. Her critique of American attitudes to the prospect for democracy in Italy provides perspective on the ambiguity of American global leadership today

    The Relevance of Giuseppe Mazzini's Ideas of Insurgency to the American Slavery Crisis of the 1850s

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    This chapter discusses Mazzini's influence in the context of the slavery crisis of the 1850s in the United States. That decade, which saw a crisis erupt in Kansas over the question of whether slavery should be allowed to expand, ended dramatically at Harpers Ferry, Virginia, where the violent abolitionist John Brown led a doomed attempt to arm and liberate slaves. Mazzini studied, wrote about, and on occasion attempted to enact popular insurrection and guerilla warfare. His ideas became essential to Brown's ideology and actions, which precipitated the Civil War. The chapter suggests an under-appreciated aspect of Mazzini's influence in America, invites a reassessment of the American sectional crisis of the 1850s for its transatlantic dimensions, and proposes a sobering but important dimension to the historical path of the spread of democratic nationalism. © The British Academy 2008. All rights reserved

    Faster juvenile growth promotes earlier sex change in a protandrous hermaphrodite (barramundi Lates calcarifer)

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    The relationship between growth and sexual maturation is central to understanding the dynamics of animal populations which exhibit indeterminate growth. In sequential hermaphrodites, which undergo post-maturation sex change, the size and age at which sex change occurs directly affects reproductive output and hence population productivity. However, these traits are often labile, and may be strongly influenced by heterogenous growth and mortality rates. We analysed otolith microstructure of a protandrous (i.e., male-to-female) fish (barramundi Lates calcarifer) to examine growth in relation to individual variation in the timing of sex change. Growth trajectories of individuals with contrasting life histories were examined to elucidate the direction and extent to which growth rate influences the size and age individuals change sex. Then, the relationships between growth rate, maturation schedules and asymptotic maximum size were explored to identify potential trade-offs between age at female maturity and growth potential. Rapid growth was strongly associated with decreased age at sex change, but this was not accompanied by a decrease in size at sex change. Individuals that were caught as large females grew faster than those caught as males, suggesting that fast-growing individuals ultimately obtain higher fitness and therefore make a disproportionate contribution to population fecundity. These results indicate that individual-level variation in maturation schedules is not reflective of trade-offs between growth and reproduction. Rather, we suggest that conditions experienced during the juvenile phase are likely to be a key determinant of post-maturation fitness. These findings highlight the vulnerability of sex-changing species to future environmental change and harvest

    B--> K^* l^+ l^- decay in the two Higgs doublet model with flavor changing neutral currents

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    We study the decay width, forward-backward asymmetry and the longitudinal lepton polarization for the exclusive decay B --> K^* l^+ l^- in the two Higgs doublet model with three level flavor changing neutral currents (model III) and analyse the dependencies of these quantities on the the selected parameters, \xi^{U,D}, of model III including the next to leading QCD corrections. It is found that to look for charged Higgs effects, the measurements of the branching ratio, forward-backward asymmetry and the longitudinal lepton polarization for the decay B --> K^* l^+ l^- are promising.Comment: 17 pages, 6 figure

    Strong coupling constants of heavy spin--3/2 baryons with light pseudoscalar mesons

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    The strong coupling constants among members of the heavy spin--3/2 baryons containing single heavy quark with light pseudoscalar mesons are calculated in the framework of the light cone QCD sum rules. Using symmetry arguments, the structure independent relations among different correlation functions are obtained. It is shown that all possible transitions can be described in terms of one universal invariant function whose explicit expression is Lorenz structure dependent.Comment: 16 Pages, 1 figure and 1 Tabl

    Lepton polarization and CP-violating effects in "B -> K^* tau^+ tau^-" decay in standard and two Higgs doublet models

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    The most general model independent expressions for the CP-violating asymmetry, longitudinal, transversal and normal polarizations of leptons are derived. Application of these general results to the concrete models such as Standard model and three different types of two Higgs doublet model is discussed.Comment: 18 pages, 8 postscripted figure

    Managing complex respiratory patients in the community: an evaluation of a pilot integrated respiratory care service

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    Introduction: In the UK, there is significant variation in respiratory care and outcomes. An integrated approach to the management of high-risk respiratory patients, incorporating specialist and primary care teams' expertise, is the basis for new integrated respiratory services designed to reduce this variation; however, this model needs evaluating.Methods: To evaluate an integrated service managing high-risk respiratory patients, electronic searches for patients with asthma and chronic obstructive pulmonary disease at risk of poor outcomes were performed in two general practitioner (GP) practices in a local service-development initiative. Patients were reviewed at joint clinics by primary and secondary care professionals. GPs also nominated patients for inclusion. Reviews were delivered to best standards of care including assessments of diagnosis, control, spirometry, self-management, education, medication, inhaler technique and smoking cessation support. Follow-up of routine clinical data collected at 9-months postclinic were compared with seasonally matched 9-months prior to integrated review.Results: 82 patients were identified, 55 attended. 13 (23.6%) had their primary diagnosis changed. In comparison with the seasonally adjusted baseline period, in the 9-month follow-up there was an increase in inhaled corticosteroid prescriptions of 23.3%, a reduction in short-acting β2-agonist prescription of 33.3%, a reduction in acute respiratory exacerbations of 67.6%, in unscheduled GP surgery visits of 53.3% and acute respiratory hospital admissions reduced from 3 to 0. Only 4 patients (7.3%) required referral to secondary care. Health economic evaluation showed respiratory-related costs per patient reduced by £231.86.Conclusions: Patients with respiratory disease in this region at risk of suboptimal outcomes identified proactively and managed by an integrated team improved outcomes without the need for hospital referral

    Rare B -> K^* l^+ l^- decay, two Higgs doublet model, and light cone QCD sum rules

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    The decay width, forward-backward asymmetry and lepton longitudinal and transversal polarization for the exclusive K^* -> l^+ l^- decay in a two Higgs doublet model are computed. It is shown that all these quantities are very effective tools for establishing new physics.Comment: 18 pages, 7 figures, LaTeX formatte
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