0++0^{++} Resonances Observed at BES

In last 10 years, $0^{++}$ resonances have been observed and studied at BES in many processes, such as $J/\psi\to\gamma\pi^+\pi^-\pi^+\pi^-$, $\gamma\pi^+\pi^-$, $\gamma\pi^0\pi^0$, $\gamma K^+K^-$, $\gamma K_SK_S$, $\gamma\omega\phi$, $\omega\pi^+\pi^-$, $\omega K^+K^-$, $\phi\pi^+\pi^-$, $\phi K^+K^-$, $\psi(2S)\to J/\psi\pi^+\pi^-$, $\chi_{c0}\to\pi^+\pi^-K^+K^-$, $\pi^+\pi^-\pi^+\pi^-$ etc.. The results on $0^{++}$ resonances observed at BES are reviewed.Comment: Plenary talk at SCADRON70, Lisbon, Feb. 200

Inappropriate prescription of prism glasses for obligate fixation disparity measured with the Pola test

In the subjective measurement of fixation disparity (FD), the subject sees and fuses contours presented in the peripheral macular areas of both eyes ('fusion loek', a square for instanee). The pointing direction of the foveolae of both eyes relative to each other is determined by means of two haploscopically seen objects presented in the central visual field (Fig. la). ..

Surjective H-Colouring over reflexive digraphs

The Surjective H-Colouring problem is to test if a given graph allows a vertex-surjective homomorphism to a fixed graph H. The complexity of this problem has been well studied for undirected (partially) reflexive graphs. We introduce endo-triviality, the property of a structure that all of its endomorphisms that do not have range of size 1 are automorphisms, as a means to obtain complexity-theoretic classifications of Surjective H-Colouring in the case of reflexive digraphs. Chen (2014) proved, in the setting of constraint satisfaction problems, that Surjective H-Colouring is NP-complete if H has the property that all of its polymorphisms are essentially unary. We give the first concrete application of his result by showing that every endo-trivial reflexive digraph H has this property. We then use the concept of endo-triviality to prove, as our main result, a dichotomy for Surjective H-Colouring when H is a reflexive tournament: if H is transitive, then Surjective H-Colouring is in NL; otherwise, it is NP-complete. By combining this result with some known and new results, we obtain a complexity classification for Surjective H-Colouring when H is a partially reflexive digraph of size at most 3

NJL with eight quark interactions: Chiral phases at finite T

The thermodynamic potential and thermal dependence of low lying mass spectra of scalars and pseudoscalars are evaluated in a generalized Nambu -- Jona-Lasinio model, which incorporates eight-quark interactions. These are necessary to stabilize the scalar effective potential for the light and strange quark flavors, which would be otherwise unbounded from below. In addition it turns out that they are also crucial to i) lower the temperature of the chiral transition, in conformity with lattice calculations, ii) sharpen the temperature interval in which the crossover occurs, iii) or even allow for first order transitions to occur with realistic quark mass values, from certain critical values of the parameters. These are unprecedented results which cannot be obtained within the NJL approaches restricted to quartic and six-quark interactions.Comment: 6 pages, 3 figures, Talk presented at SCADRON 70 Workshop on Scalar Mesons and Related Topics, Lisbon, 11-16 February 200

What do We Know about Social Entrepreneurship: An Analysis of Empirical Research

Despite the growing attention to social entrepreneurship as a scholarly field of research, it is still in a stage of infancy. Research in the past two decades has been primarily dedicated to establishing a conceptual foundation, which has resulted in a considerable stream of conceptual papers. Empirical articles have gradually appeared since the turn of the century. Although they are still outnumbered by conceptual articles, empirical articles are of considerable significance for the evolution of social entrepreneurship as a field of scientific inquiry. The purpose of this paper is to gauge the current state of empirical research in the field by reviewing 31 empirical research studies on social entrepreneurship, classifying them along four dimensions and summarising research findings for each of these dimensions. To serve this purpose in a meaningful fashion requires discriminating between different perspectives on social entrepreneurship. Hence, four different schools of thought are presented, and the articles in our sample are classified accordingly

Social Entrepreneurship and Performance: The Role of Perceived Barriers and Risk

This study investigates if and in what way social entrepreneurs are hampered in turning their efforts into sustainable organizations. Using binary logit regressions and unique data containing approximately 26,000 individual-level data points for 36 countries, this

Seguidilla und Mantilla - das Spanienbild im Libretto von opéra-comique und opéra-bouffe:Untersuchungen an Hand von ausgewählten Librettotexten des 19. Jahrhunderts

Die als Folge der Romantik auftretende Mode der couleur locale und des Exotismus prägt das Kunstschaffen des 19. Jahrhunderts, so auch die populäre, typisch französische Unterhaltungsform jener Zeit, die opéra-comique bzw. – nach 1850 – die sich daraus entwickelnde opéra-bouffe. Die vorliegende Untersuchung konzentriert sich auf die hispanistisch inspirierten Librettotexte dieser Opernform und stellt deren Libretti als sorgfältig komponierte Intrigenkomödien heraus, die das noch unbekannte Spanien darstellen, indem sie zentrale Epochen der spanischen Geschichte und typisch spanische Charakterzüge aufgreifen. Nach 1850 trägt die Kritik an Missständen in der französischen Gesellschaft häufig spanische Verkleidung. Das daraus entstehende Spanienbild ist ein Amalgam von Realitätsbezügen und Klischees, deren Kern jedoch authentisch ist. Zusammen mit der gezielt eingesetzten, spanisch klingenden Musik entsteht ein Unterhaltungstheater, das jedoch auf spanischem Boden nicht nur Zustimmung findet.<br

Social Entrepreneurship in the Modern Economy: Warm Glow, Cold Feet

This study tests and extends current knowledge on the causes of social entrepreneurship: a type of entrepreneurship that concerns the process of discovering, evaluating, and pursuing opportunities aimed at the creation of social value. In contrast to what is common in this research domain, this study applies a research design based on unique, large-scale and internationally comparable survey data. Various research themes are addressed such as the occurrence and drivers of social entrepreneurship at the macro-level, factors that influence the survival of social ventures at the firm level, and the differences and commonalities between social and commercial entrepreneurs at the individual level. At the macro-level it is concluded that social entrepreneurship clearly is a global phenomenon with a prevailing role for the level of income in a country as one of the drivers of its occurrence. At the micro-level results indicate a deviating entrepreneurial profile for social entrepreneurs that tends to be, in some respects, less favorable compared to commercial entrepreneurs in terms of effort put into the organisation, self-confidence, ambition, funding and progression to more mature stages of the entrepreneurial process. The results of this thesis are of particular interest for public policy-makers, private foundations, and support organizations who want to promote social entrepreneurship and improve the sector infrastructure. This study advocates taking account for this deviating entrepreneurial profile