18,748 research outputs found

    Phenomenological Consequences of Soft Leptogenesis

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    Soft supersymmetry breaking terms involving heavy singlet sneutrinos can be the dominant source of leptogenesis. The relevant range of parameters is different from standard leptogenesis: a lighter Majorana mass, M < 10^9 GeV (allowing a solution of the gravitino problem), and smaller Yukawa couplings, Y_N < 10^{-4}. We investigate whether the various couplings of the singlet sneutrinos, which are constrained by the requirement of successful `soft leptogenesis', can have observable phenomenological consequences. Specifically, we calculate the contributions of the relevant soft supersymmetric breaking terms to the electric dipole moments of the charged leptons and to lepton flavor violating decays. Our result is that these contributions are small.Comment: 11 pages, 1 figure; v2: an additional contribution is considered (modifying: fig. 1, eq. 10-13, 22) and a reference added. Conclusions unchange

    Seesaw Mass Matrix Model of Quarks and Leptons with Flavor-Triplet Higgs Scalars

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    In a seesaw mass matrix model M_f = m_L M_F^{-1} m_R^\dagger with a universal structure of m_L \propto m_R, as the origin of m_L (m_R) for quarks and eptons, flavor-triplet Higgs scalars whose vacuum expectation values v_i are proportional to the square roots of the charged lepton masses m_{ei}, i.e. v_i \propto \sqrt{m_{ei}}, are assumed. Then, it is investigated whether such a model can explain the observed neutrino masses and mixings (and also quark masses and mixings) or not.Comment: version accepted by EPJ

    Genomic homogeneity in fibrolamellar carcinomas

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    Background-Fibrolamellar carcinoma (FLC) is a variant of hepatocellular carcinoma (HCC) with distinctive clinical and histological features. To date there have been few studies on the genotypic aspects of FLC and no previous attempts have been made to use the arbitrarily primed-polymerase chain reaction (AF-FCR) technique to detect genetic alterations in this disease.Aim-The aim of this study was to assess the degree of genomic heterogeneity of FEC using the AP-PCR technique. Methods-A fetal of 50 tissue samples of primary and metastatic FLCs from seven patients were microdissected. AP-PCR amplification of each genomic DNA sample was carried out using two arbitrary primers.Results-DNA fingerprints of the primary FLCs and all their metastatic lesions (both synchronous and metachronous disease) were identical in an individual patient. The fingerprints were different between tumours of different patients. No evidence of intratumour heterogeneity was observed.Conclusions-Such genomic homogeneity in FLCs may explain their indolent growth. The absence of clonal evolution, which is present in other tumours (particularly HCCs), may explain the distinct behaviour in this tumour. The tumorigenic pathway and degree of somatic genomic changes in this disease may be less complex than in HCC

    A Unified Description of Quark and Lepton Mass Matrices in a Universal Seesaw Model

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    In the democratic universal seesaw model, the mass matrices are given by \bar{f}_L m_L F_R + \bar{F}_L m_R f_R + \bar{F}_L M_F F_R (f: quarks and leptons; F: hypothetical heavy fermions), m_L and m_R are universal for up- and down-fermions, and M_F has a structure ({\bf 1}+ b_f X) (b_f is a flavour-dependent parameter, and X is a democratic matrix). The model can successfully explain the quark masses and CKM mixing parameters in terms of the charged lepton masses by adjusting only one parameter, b_f. However, so far, the model has not been able to give the observed bimaximal mixing for the neutrino sector. In the present paper, we consider that M_F in the quark sectors are still "fully" democratic, while M_F in the lepton sectors are partially democratic. Then, the revised model can reasonably give a nearly bimaximal mixing without spoiling the previous success in the quark sectors.Comment: 7 pages, no figur

    Advance care planning in 21st century Australia: a systematic review and appraisal of online advance care directive templates against national framework criteria

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    Objectives A drive to promote advance care planning at a population level has led to a proliferation of online advance care directive (ACD) templates but little information to guide consumer choice. The current study aimed to appraise the quality of online ACD templates promoted for use in Australia. Methods A systematic review of online Australian ACD templates was conducted in February 2014. ACD templates were identified via Google searches, and quality was independently appraised by two reviewers against criteria from the 2011 report A National Framework for Advance Care Directives. Bias either towards or against future medical treatment was assessed using criteria designed to limit subjectivity. Results Fourteen online ACD templates were included, all of which were available only in English. Templates developed by Southern Cross University best met the framework criteria. One ACD template was found to be biased against medical treatment – the Dying with Dignity Victoria Advance Healthcare Directive. Conclusions More research is needed to understand how online resources can optimally elicit and record consumers’ individual preferences for future care. Future iterations of the framework should address online availability and provide a simple rating system to inform choice and drive quality improvement

    Evolution of the Yukawa coupling constants and seesaw operators in the universal seesaw model

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    The general features of the evolution of the Yukawa coupling constants and seesaw operators in the universal seesaw model with det M_F=0 are investigated. Especially, it is checked whether the model causes bursts of Yukawa coupling constants, because in the model not only the magnitude of the Yukawa coupling constant (Y_L^u)_{33} in the up-quark sector but also that of (Y_L^d)_{33} in the down-quark sector is of the order of one, i.e., (Y_L^u)_{33} \sim (Y_L^d)_{33} \sim 1. The requirement that the model should be calculable perturbatively puts some constraints on the values of the intermediate mass scales and tan\beta (in the SUSY model).Comment: 21 pages, RevTex, 10 figure

    Neutrino masses and R-parity violation

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    We review different contributions to the neutrino masses in the context of R-parity violating supersymmetry in a basis independent manner. We comment on the generic spectrum expected in such a scenario comparing different contributions.Comment: Invited brief review for Mod. Phys. Lett. A, 15 pages, uses axodraw.st

    A Detailed Analysis of One-loop Neutrino Masses from the Generic Supersymmetric Standard Model

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    In the generic supersymmetric standard model which had no global symmetry enforced by hand, lepton number violation is a natural consequence. Supersymmetry, hence, can be considered the source of experimentally demanded beyond standard model properties for the neutrinos. With an efficient formulation of the model, we perform a comprehensive detailed analysis of all one-loop contributions to neutrino masses.Comment: 27 pages Revtex, no figur

    Prehospital delay for acute coronary syndrome in China

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    Background: Despite the effectiveness of timely reperfusion therapy for acute coronary syndrome, prehospital delay remains a global concern. Objective: This article assesses the state-of-the-science regarding prehospital delay for acute coronary syndrome in China. Method: Electronic databases and hand searching were undertaken using key words such as prehospital delay, care-seeking delay, coronary heart disease, heart disease, acute coronary syndrome, unstable angina pain, acute myocardial infarction, cardiovascular disease, chest pain, and Chin (China/Chinese). The Chinese search was supervised by a Chinese health librarian. Results: Based on the search criteria, 28 studies were identified and reviewed using a standardized data extraction tool. Older age, attribution of symptoms to noncardiac causes, lack of health insurance coverage, poor access to transportation, and female sex were identified as contributing to prehospital delay. Conclusion: Health system reforms in China are necessary, particularly with regard to addressing the needs of older people, women, and other vulnerable populations in the context of the rising number of people with coronary heart disease. Developing targeted strategies, learned from both national and international experience, are required to develop targeted interventions. Copyright © 2010 Wolters Kluwer Health. Lippincott Williams & Wilkins

    Nurse educators in Australia: High job satisfaction despite role ambiguity

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    Purpose: The purpose of this study was to describe the nurse educator role in Australian hospitals, including their practice and performance standards. Methods: A cross-sectional, online survey of nurse educators employed in acute care hospitals in Australia was administered over a three-month period. The survey comprised established and researcher-developed scales, and a single open-ended question. Quantitative data was analysed using descriptive statistics. Qualitative data was analysed using a general inductive approach. Results: Nurse educators who were more likely to fulfill nurse educator competency practice domains had master’s degrees in education, defined professional development needs, and met regularly with their managers. These educators also had higher levels of job satisfaction. Participants identified that role ambiguity and role confusion adversely impacted nurse educator role expectations, responsibilities, and job satisfaction. Despite this, the majority of educators intended to stay in their role for the foreseeable future. Conclusions: Role ambiguity influenced professional identity and job satisfaction, highlighting the need for clarification of nurse educator roles. These findings suggest the need for review of the nurse educator role and incorporation of professional and educational requirements and practice competencies. Ongoing role monitoring is recommended to identify the effects of role change
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