Heavy-to-light transition form factors and their relations in light-cone QCD sum rules

The improved light-cone QCD sum rules by using chiral current correlator is systematically reviewed and applied to the calculation of all the heavy-to-light form factors, including all the semileptonic and penguin ones. By choosing suitable chiral currents, the light-cone sum rules for all the form factors are greatly simplified and depend mainly on one leading twist distribution amplitude of the light meson. As a result, relations between these form factors arise naturally. At the considered accuracy these relations reproduce the results obtained in the literature. Moreover, since the explicit dependence on the leading twist distribution amplitudes is preserved, these relations may be more useful to simulate the experimental data and extract the information on the distribution amplitude.Comment: 1+16 pages, no figure

#FeesMustFall# movement in the post-apartheid era: legitimacy battle for leaders

Purpose Underpinned by institutional legitimacy, this study explores how South African public university senior managers struggled to maintain legitimacy during an unplanned radical change process. Design/methodology/approach Gioia's grounded theory analysis approach is employed to analyse interviews with 37 senior managers of public-funded universities in South Africa. Findings This study's findings show that a change without proper planning severely damages institutions in all aspects of leadership's normative, empirical, moral and pragmatic legitimacy. Research limitations/implications This study contributes to the literature on legitimacy by illustrating the importance of institutional legitimacy during unplanned social change and the factors that negate legitimacy. Originality/value Though other legitimacy models have been well developed, they do not apply to such unplanned social change in organisations. This study shows a different angle of the legitimacy crisis under unplanned social change conditions

Information sharing, bank penetration and tax evasion in emerging markets

Tax evasion, which is typically considered an illegal activity, is a critical problem and is considered a barrier to economic growth. A review of the literature shows that tax and social security contributions, regulations, public sector services, the quality of institutions and tax compliance, play important roles in determining the degree to which firms attempt to evade taxes. Measuring tax evasion is problematic due to data requirements and inadequacies. Few tax evasion indices have been estimated but it appears that they cannot be used for international comparisons across countries. This important issue has largely been ignored in the literature, in particular for emerging markets. Consequently, this paper is conducted to develop a new tax evasion index (TEI) using the most substantial and recent data from the standardized World Bank Enterprises Survey 2006–2017. In addition, using the newly developed TEI, the paper examines the importance and contribution of information sharing and bank penetration to the degree of tax evasion in emerging markets. The paper uses a sample of 112 emerging markets from 2006–2017 and the Tobit model in estimation. The empirical findings from the paper indicate that the average TEI during the 2006– 2017 period for emerging markets is 0.62, with a range of (0.25, 0.75). In addition, we find that information sharing and bank penetration negatively affect the degree of tax evasion, as proxied by the TEI, in emerging markets. The empirical results also confirm the view that large firms are considered to have adopted good tax compliance practices, while firms located in remote areas are more likely to evade taxes. Policy implications have emerged on the basis of the empirical findings from the paper

Scalar Decay in Chaotic Mixing

I review the local theory of mixing, which focuses on infinitesimal blobs of scalar being advected and stretched by a random velocity field. An advantage of this theory is that it provides elegant analytical results. A disadvantage is that it is highly idealised. Nevertheless, it provides insight into the mechanism of chaotic mixing and the effect of random fluctuations on the rate of decay of the concentration field of a passive scalar.Comment: 35 pages, 15 figures. Springer-Verlag conference style svmult.cls (included). Published in "Transport in Geophysical Flows: Ten Years After," Proceedings of the Grand Combin Summer School, 14-24 June 2004, Valle d'Aosta, Italy. Fixed some typo

What Does The Korringa Ratio Measure?

We present an analysis of the Korringa ratio in a dirty metal, emphasizing the case where a Stoner enhancement of the uniform susceptibilty is present. We find that the relaxation rates are significantly enhanced by disorder, and that the inverse problem of determining the bare density of states from a study of the change of the Knight shift and relaxation rates with some parameter, such as pressure, has rather constrained solutions, with the disorder playing an important role. Some preliminary applications to the case of chemical substitution in the Rb$_{3-x}$K$_x$C$_{60}$ family of superconductors is presented and some other relevant systems are mentioned.Comment: 849, Piscataway, New Jersey 08855 24 June 199

Dutch higher education and Chinese students in the Netherlands

The number of Chinese students in the Dutch higher education sector has grown rapidly. In 2014 the number of Chinese BA and MA students reached 4638, or about 7 percent of the population of international students in the Netherlands. The number of formally employed PhD students in that year was 427. After the Germans, the Chinese have become the second largest group of international students. Dutch HBO schools (‘universities of applied sciences’) used to attract about half of all Chinese students in the Netherlands, but their share has been dropping perceptibly in recent years. The presence of Chinese students has become a structural aspect of the Dutch higher education sector. In the competition for student talent from China, the Netherlands lose out to top-ranked universities in the English-speaking world. Nevertheless, the Netherlands has proven to be quite successful as one of the most English of all non-English-speaking countries with a very wide range of study programmes in English. When looking at the relative costs of studying abroad the Netherlands occupies a middle position. As a result, Chinese students often come to the Netherlands as an excellent second-best choice. Self-development and exposure to foreign cultures are the most important reasons to study abroad. Another consideration is the hope of gaining a competitive advantage in the Chinese job market upon return. Students view the Netherlands as safe, egalitarian, and open to different cultures. This appreciation of certain aspects of Dutch society is also a reflection on satisfaction with some social changes inherent to China’s rapid modernization. Students appreciate the fact that Dutch education puts more emphasis on skills and the use of knowledge. Contacts with international students is an important aspect of positive experiences of Chinese students. Relations with Dutch students seems to be less common. Students encounter problems with a language, different customs, integration, and even prejudice in Dutch society. Many students also report being uncomfortable being exposed by questions and criticisms of Chinese politics. These tensions could potentially harm the image of the Netherlands in China and affect student inflow. Chinese bachelor’s students perform relatively well in comparison with Dutch and many other international students. A relatively high percentage successfully completes their education and mostly within the nominal study time. In comparison with students from other non-EEA countries the stay rate for employment reasons after graduation is relatively low and continues to drop. Most Chinese students are enrolled in programmes in the field of business, science, and engineering. As a result, most of the graduates who stay find work in financial services, trade, business, communication and hospitality. Only students in technology and science stay relatively less often for employment after graduation.Asian Studie

More on scattering of Chern-Simons vortices

I derive a general formalism for finding kinetic terms of the effective Lagrangian for slowly moving Chern-Simons vortices. Deformations of fields linear in velocities are taken into account. From the equations they must satisfy I extract the kinetic term in the limit of coincident vortices. For vortices passing one over the other there is locally the right-angle scattering. The method is based on analysis of field equations instead of action functional so it may be useful also for nonvariational equations in nonrelativistic models of Condensed Matter Physics.Comment: discussion around Eq.(45) is generalised, one more condition for the local right-angle scattering is adde

Strong Couplings of Heavy Mesons to A Light Vector Meson in QCD

We make a detailed analysis of the $BB\rho(DD\rho)$ and $B^*B\rho(D^{*}D\rho)$ strong couplings $g_{BB\rho}(g_{DD\rho})$ and $g_{B^*B\rho}(g_{D^{*}D\rho})$ using QCD light cone sum rules(LCSR). The existing some negligence is pointed out in the previous LCSR calculation on $g_{B^*B\rho} (g_{D^{\ast}D\rho}$) and an updated estimate is presented. Our findings can be used to understand the behavior of the $B,D \to \rho$ semileptonic form factors at large momentum transitions.Comment: 15 pages, latex, 2 figures, version appearing in PRD, typos correcte

Micropatterned 2D Hybrid Perovskite Thin Films with Enhanced Photoluminescence Lifetimes

The application of luminescent materials in display screens and devices requires micropatterned structures. In this work, we have successfully printed microstructures of a two-dimensional (2D), orange-colored organic/inorganic hybrid perovskite ((C6H5CH2NH3)2PbI4) using two different soft lithography techniques. Notably, both techniques yield microstructures with very high aspect ratios in the range of 1.5-1.8. X-ray diffraction reveals a strong preferential orientation of the crystallites along the c-axis in both patterned structures, when compared to nonpatterned, drop-casted thin films. Furthermore, (time-resolved) photoluminescence (PL) measurements reveal that the optical properties of (C6H5CH2NH3)2PbI4 are conserved upon patterning. We find that the larger grain sizes of the patterned films with respect to the nonpatterned film give rise to an enhanced PL lifetime. Thus, our results demonstrate easy and cost-effective ways to manufacture patterns of 2D organic/inorganic hybrid perovskites, while even improving their optical properties. This demonstrates the potential use of color-tunable 2D hybrids in optoelectronic devices