662 research outputs found

    Higher-order multipole amplitudes in charmonium radiative transitions

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    Using 24 million ψψ(2S)\psi' \equiv \psi(2S) decays in CLEO-c, we have searched for higher multipole admixtures in electric-dipole-dominated radiative transitions in charmonia. We find good agreement between our data and theoretical predictions for magnetic quadrupole (M2) amplitudes in the transitions ψγχc1,2\psi' \to \gamma \chi_{c1,2} and χc1,2γJ/ψ\chi_{c1,2} \to \gamma J/\psi, in striking contrast to some previous measurements. Let b2Jb_2^J and a2Ja_2^J denote the normalized M2 amplitudes in the respective aforementioned decays, where the superscript JJ refers to the angular momentum of the χcJ\chi_{cJ}. By performing unbinned maximum likelihood fits to full five-parameter angular distributions, we determine the ratios a2J=1/a2J=2=0.670.13+0.19a_2^{J=1}/a_2^{J=2} = 0.67^{+0.19}_{-0.13} and a2J=1/b2J=1=2.270.99+0.57a_2^{J=1}/b_2^{J=1} = -2.27^{+0.57}_{-0.99}, where the theoretical predictions are independent of the charmed quark magnetic moment and are a2J=1/a2J=2=0.676±0.071a_2^{J=1}/a_2^{J=2} = 0.676 \pm 0.071 and a2J=1/b2J=1=2.27±0.16a_2^{J=1}/b_2^{J=1} = -2.27 \pm 0.16.Comment: 32 pages, 7 figures, acceptance updat

    Dalitz Plot Analysis of Ds to K+K-pi+

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    We perform a Dalitz plot analysis of the decay Ds to K+K-pi+ with the CLEO-c data set of 586/pb of e+e- collisions accumulated at sqrt(s) = 4.17 GeV. This corresponds to about 0.57 million D_s+D_s(*)- pairs from which we select 14400 candidates with a background of roughly 15%. In contrast to previous measurements we find good agreement with our data only by including an additional f_0(1370)pi+ contribution. We measure the magnitude, phase, and fit fraction of K*(892) K+, phi(1020)pi+, K0*(1430)K+, f_0(980)pi+, f_0(1710)pi+, and f_0(1370)pi+ contributions and limit the possible contributions of other KK and Kpi resonances that could appear in this decay.Comment: 21 Pages,available through http://www.lns.cornell.edu/public/CLNS/, submitted to PR

    Search for D0 to p e- and D0 to pbar e+

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    Using data recorded by CLEO-c detector at CESR, we search for simultaneous baryon and lepton number violating decays of the D^0 meson, specifically, D^0 --> p-bar e^+, D^0-bar --> p-bar e^+, D^0 --> p e^- and D^0-bar --> p e^-. We set the following branching fraction upper limits: D^0 --> p-bar e^+ (D^0-bar --> p-bar e^+) p e^- (D^0-bar --> p e^-) < 1.2 * 10^{-5}, both at 90% confidence level.Comment: 10 pages, available through http://www.lns.cornell.edu/public/CLNS/, submitted to PRD. Comments: changed abstract, added reference for section 1, vertical axis in Fig.5 changed (starts from 1.5 rather than 2.0), fixed typo

    Charmonium decays to gamma pi0, gamma eta, and gamma eta'

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    Using data acquired with the CLEO-c detector at the CESR e+e- collider, we measure branching fractions for J/psi, psi(2S), and psi(3770) decays to gamma pi0, gamma eta, and gamma eta'. Defining R_n = B[ psi(nS)-->gamma eta ]/B[ psi(nS)-->gamma eta' ], we obtain R_1 = (21.1 +- 0.9)% and, unexpectedly, an order of magnitude smaller limit, R_2 < 1.8% at 90% C.L. We also use J/psi-->gamma eta' events to determine branching fractions of improved precision for the five most copious eta' decay modes.Comment: 14 pages, available through http://www.lns.cornell.edu/public/CLNS/, published in Physical Review

    Entrepreneurial intentions and entrepreneurship education to University students in Portugal

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    [EN] This article analyzes entrepreneurial intentions and motivations that encourage university students of Tourism to create their own company. Methodology is based on an empirical study, using a questionnaire adapted from a model of Veciana and Urbano (Actitudes de los estudiantes universitarios hacia la creación de empresas: un estudio empírico comparativo entre Catalunya y Puerto Rico. El emprendedor innovador y la creación de empresas de I + D + I, University of Valencia, pp 35 58, 2004), including the desirability and viability concepts. One hundred and sixty students answered the questionnaire from a total study population of 243 official Tourism degree students of the Superior Institute of Accounting and Management of Porto. This research finds out that the university students have a very positive perception about the desire to create their own company; a 90 % of students express their desire to do it, and 83.5 % express their intention. Moreover, a 57.5 % think that within actual crisis it is more difficult to do than before it. This research lets us get an in-depth study of a student of Tourism degree, finding out his entrepreneurial attitudes. It can be the first step to wake up and encourage students interest for starting up their own business.Del Rio-Rama, MDLC.; Peris-Ortiz, M.; Álvarez García, J.; Rueda Armengot, C. (2016). Entrepreneurial intentions and entrepreneurship education to University students in Portugal. Technology, Innovation and Education. 2(7):1-11. doi:10.1186/s40660-016-0013-5S11127Ajzen I (1991) The theory of plannes behavior. Organ Behav Hum Decis Process 50:179–211Aponte M (2002) Factores condicionantes de la creación de empresas en Puerto Rico: un enfoque institucional. Doctoral dissertation, Autonomous University of BarcelonaAponte M, Urbano D, Veciana JM (2006) Actitudes hacia la creación de empresas: un estudio comparativo entre Catalunya y Puerto Rico. Centro de Investigaciones Comerciales e Iniciativas Académicas de la Facultad de Administración de Empresas. Forum Empresarial 11(2):52–75Bae TJ, Qian S, Miao C, Fiet JO (2014) The relationship between entrepreneurship education and entrepreneurial intentions: a meta-analytic review. Entrep Theory Pract 38(2):217–254Brice J (2004) The role of personality dimensions on the formation of entrepreneurial intentions. USASBE Small Business Advancement National Center. University of Central Arkansas, USACabana-Villca R, Cortes-Castillo I, Plaza-Pasten D, Castillo-Vergara M, Alvarez-Marin A (2013) Análisis de las capacidades emprendedoras potenciales y efectivas en alumnos de centros de educación superior. J Technol Manag Innov 8(1):65–75Davidsson P (1989) Continued entrepreneurship and small firm business. Stockholm School of Economics, StockholmDavidsson P (1995) Culture, structure and regional levels of entrepreneurship. Entrep Reg Dev 7(1):41–62De Jorge-Moreno J, Castillo LL, Triguero MS (2012) The effect of business and economics education programs on students’ entrepreneurial intention. Eur J Train Dev 36(4):409–425Díaz JC, Hernández RM, Barata ML (2007) Estudiantes universitarios y creación de empresas. Un análisis comparativo entre España y Portugal. In Ayala, J.C. (coord.) Conocimiento, innovación y emprendedores: camino al futuro. Grupo FEDRA, MadridDo Paço AMF, Ferreira JM, Raposo M, Rodrigues RG, Dinis A (2011) Behaviours and entrepreneurial intention: empirical findings about secondary students. J Int Entrep 9(1):20–38Dohse D, Walter SG (2010) The role of entrepreneurship education and regional context in forming entrepreneurial intentions (No. 2010, 18). Document de treball de l’IEBEuropean Commission (2006). Entrepreneurship education in Europe: Fostering entrepreneurial mindsets through education and learning, Final Proceedings of the Conference on Entrepreneurship Education in OsloEurostat (2014) Informes sobre el empleo en la Unión Europea. Available in: http://europa.eu/publications/statistics/index_es.htmFuentes F, Saco F, Rodríguez P (2013) Estudio sobre el perfil emprendedor en el alumnado universitario de Córdoba. UCO Consejo Social de la Universidad de Córdoba, III Edición, Córdoba, pp 1–180Fuentes García FJ (2007) Análisis del Perfil Emprendedor del alumnado universitario y preuniversitario de Córdoba. Consejo Social Universidad de Córdoba, pp 1–105Genesca Garrigosa E, Veciana Verges JM (1984) Actitudes hacia la creación de empresas. Información Comercial Española 611:147–155Gerba DT (2012) Impact of entrepreneurship education on entrepreneurial intentions of business and engineering students in Ethiopia. Afr J Econ Manag Stud 3(2):258–277Gorman G, Hanlon D, King W (1997) Some research perspectives on entrepreneurship education and education for small business management: a ten-year literature review. Int Small Bus J 15(3):56–77Guerrero M, Rialp J, Urbano D (2008) The impact of desirability and feasibility on entrepreneurial intentions: a structural equation model. Int Entrep Manag J 4(1):35–50Haynie JM, Shepherd DA, McMullen JS (2009) An opportunity for me? The role of resources in opportunity evaluation decisions. J Manage Stud 46(3):337–361Hernangomez J, Martín N, Rodriguez AI, Saboia F (2005) El emprendedor nace o se hace? Un análisis de los determinantes del espíritu emprendedor. XVI Spanish-Portuguese Meeting of Scientic Management. Sevilla:33–44Hmieleski KM, Corbett AC (2006) Proclivity for improvisation as a predictor of entrepreneurial intentions. J Small Bus Manage 44(1):45–63Honjo Y (2004) Growth of new start-up firms: evidence from the Japanese manufacturing industry. Appl Econ Lett 11(1):21–32Hyde GC (1989) The relationship between policy and research. In Rosa, P.; Birley, S. Cannon, T. and O´Neill, K. The Role and Contribution of Small Business Research, Chap. 3:55–77, Institute ReportKolvereid L (1996) Prediction of employment status choice intentions. Entrep Theory Pract 21(1):47–57Kourilsky ML, Walstad WB (1998) Entrepreneurship and female youth: knowledge, attitude, gender differences, and educational practices. J Bus Ventur 13(1):77–88Krueger N, Brazeal D (1994) Entrepreneurial Potencial and Potencial Entrepreneurs. Entrep Theory Pract 18(3):91–104Krueger NF, Carsrud AL (1993) Entrepreneurial intentions: applying the theory of planned behaviour. Entrep Reg Dev 5(4):315–330Lanero A, Vázquez JL, Gutiérrez P, García MP (2011) The impact of entrepreneurship education in European universities: an intention-based approach analyzed in the Spanish area. Int Rev Public Nonprofit Marketin 8(2):111–130Miller BK, Bell JD, Palmer M, González A (2009) Predictors of entrepreneurial intentions: a quasi-experiment comparing students enrolled in introductory management and entrepreneurship classes. J Bus Entrep 21(2):39–62Neck HM, Zacharakis AL, Bygrave WD, Reynolds PD (2003) Global entrepreneurship monitor: 2002 executive report. Babson College, Babson, MANorth DC (1990) Institutions, Institutional Change and Economic Performance. Cambridge University Press, Cambridge (UK)North D (1993) Instituciones, cambio institucional y desempeño económico. Fondo de Cultura Económica, MéxicoNorth DC (2005) Understanding the Process of Economic Change. Academic Foundation. University Press, PrincentonGEM Portugal (2012) Estudo sobre o Empreendedorismo. Global Entrepreneruship Monitor (GEM). Instituto Universitário de Lisboa (ISCTEIUL) http://web.spi.pt/GEMportugal2012/files/GEM_PORTUGAL_2012.pdfRaposo M, do Paço A, Ferreira J (2008a) Entrepreneur’s profile: a taxonomy of attribu tes and motivations of university students. J Small Bus Enterp Dev 15(2):405–420Raposo MLB, Ferreira JJM, do Paço AMF, Rodrigues RJG (2008b) Propensity to firm creation: empirical research using structural equations. Int Entrep Manag J 4(4):485–504Robinson PB, Stimpson DV, Huefner JC, Hunt HK (1991) An attitude approach to the prediction of entrepreneurship. Entrep Theory Pract 15(4):13–31Samad Aghayi J (2008) Entrepreneurship organization. Public Administration Training Center Publications, TehranScherer RF, Adams JS, Carley S, Wiebe FA (1989) Role model performance effects on development of entrepreneurial career preference. Entrep Theory and Pract, spring:53–71Scherer RF, Brodzinski JD, Wiebe F (1991) Examining the relationship between personality and entrepreneurial career preference. Entrep Reg Dev 3(2):195–206Shane S (2003) A General Theory of Enttrepreneurship- The Individual Oportunity Nexus. Edward Elgar EditoresShapero A (1982) Social dimensions of entrepreneurship. In: Kent CA et al (eds) The encyclopedia of entrepreneurship. Prentice-Hall, Englewood Cliffs, pp 72–89Shapero A, Sokol L (1982) The social dimensions of entrepreneurship.Encyclopedia of Entrepreneurship:72–90Storey DJ (1994) Employment. In Storey, D.J. Understanding the small business sector. Capítulo 6, pp. 160–203. London: RoutledgeToledano N, Urbano D (2008) Promoting entrepreneurial mindsets at universities: a case study in the South of Spain. Eur J Int Manag 2(4):382–399Trequattrini R, Lombardi R, Lardo A, Cuozzo B (2015). The Impact of Entrepreneurial Universities on Regional Growth: a Local Intellectual Capital Perspective. Journal of the Knowledge Economy, 1–13Urbano D (2006) La creación de empresas en Catalunya. Organismos de apoyo y actitudes hacia la actividad emprendedora, Ed. Generalitat de Catalunya-CIDEM, BarcelonaUrbano D, Toledano N (2008) The systems of university education and their influence on the students’ attitudes in the business world: a multiple case study. Oikos 25:87–103Veciana JM (1989) Características del empresario en España. Papeles de Economía Española 39:19–36Veciana JM, Urbano D (2004) Actitudes de los estudiantes universitarios hacia la creación de empresas: un estudio empírico comparativo entre Catalunya y Puerto Rico. El emprendedor innovador y la creación de empresas de I + D + I, University of Valencia, pp 35–58Veciana JM, Aponte M, Urbano D (2005) University student’s attitudes towards entrepreneurship: a two countries comparison. Int Entrep Manag J 1:165–182Wang CK, Wong PK (2004) Entrepreneurial interest of university students in Singapore. Technovation 24(2):163–172White SB, Reynolds PD (1996) Government programs and high growth new firms. Frontiers of Entrepreneurship Research. Center for Entrepreneurial Studies Babson College. Wellesley, MA.: 621–635Yari A, Toulabi Z, Pourashraf Y (2013) Designing propensity to entrepreneurship paradigm in Ilam universities (structural equation model approach). J Novel Appl Sci 2:872–88

    Precision Measurement of B(D+ -> mu+ nu) and the Pseudoscalar Decay Constant fD+

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    We measure the branching ratio of the purely leptonic decay of the D+ meson with unprecedented precision as B(D+ -> mu+ nu) = (3.82 +/- 0.32 +/- 0.09)x10^(-4), using 818/pb of data taken on the psi(3770) resonance with the CLEO-c detector at the CESR collider. We use this determination to derive a value for the pseudoscalar decay constant fD+, combining with measurements of the D+ lifetime and assuming |Vcd| = |Vus|. We find fD+ = (205.8 +/- 8.5 +/- 2.5) MeV. The decay rate asymmetry [B(D+ -> mu+ nu)-B(D- -> mu- nu)]/[B(D+ -> mu+ nu)+B(D- -> mu- nu)] = 0.08 +/- 0.08, consistent with no CP violation. We also set 90% confidence level upper limits on B(D+ -> tau+ nu) < 1.2x10^(-3) and B(D+ -> e+ nu) < 8.8x10^(-6).Comment: 24 pages, 11 figures and 6 tables, v2 replaced some figure vertical axis scales, v3 corrections from PRD revie

    Inclusive chi_bJ(nP) Decays to D0 X

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    Using Upsilon(2S) and Upsilon(3S) data collected with the CLEO III detector we have searched for decays of chi_bJ to final states with open charm. We fully reconstruct D0 mesons with p_D0 > 2.5 GeV/c in three decay modes (K-pi+, K-pi+pi0, and K-pi-pi+pi+) in coincidence with radiative transition photons that tag the production of one of the chi_bJ(nP) states. We obtain significant signals for the two J=1 states. Recent NRQCD calculations of chi_{bJ}(nP) --> c cbar X depend on one non-perturbative parameter per chi_bJ triplet. The extrapolation from the observed D0 X rate over a limited momentum range to a full c cbar X rate also depends on these same parameters. Using our data to fit for these parameters, we extract results which agree well with NRQCD predictions, confirming the expectation that charm production is largest for the J=1 states. In particular, for J=1, our results are consistent with c cbar g accounting for about one-quarter of all hadronic decays.Comment: Version 2 updates include corrections to important errors in Table V and VII column headers which summarize results, and additional minor edits. 17 pages, available through http://www.lns.cornell.edu/public/CLNS

    Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015

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    SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation

    Azimuthal anisotropy and correlations at large transverse momenta in p+pp+p and Au+Au collisions at sNN\sqrt{s_{_{NN}}}= 200 GeV

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    Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au+Au collisions at sNN\sqrt{s_{_{NN}}}= 200 GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au+Au collisions to those in p+pp+p at the same energy. Elliptic anisotropy, v2v_2, is found to reach its maximum at pt3p_t \sim 3 GeV/c, then decrease slowly and remain significant up to pt7p_t\approx 7 -- 10 GeV/c. Stronger suppression is found in the back-to-back high-ptp_t particle correlations for particles emitted out-of-plane compared to those emitted in-plane. The centrality dependence of v2v_2 at intermediate ptp_t is compared to simple models based on jet quenching.Comment: 4 figures. Published version as PRL 93, 252301 (2004
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