On the Nature of X(4260)

We study the property of $X(4260)$ resonance by re-analyzing all experimental data available, especially the $e^+e^- \rightarrow J/\psi\,\pi^+\pi^-,\,\,\,\omega\chi_{c0}$ cross section data. The final state interactions of the $\pi\pi$, $K\bar K$ couple channel system are also taken into account. A sizable coupling between the $X(4260)$ and $\omega\chi_{c0}$ is found. The inclusion of the $\omega\chi_{c0}$ data indicates a small value of $\Gamma_{e^+e^-}=23.30\pm 3.55$eV.Comment: Refined analysis with new experimental data included. 13 page

Facing unemployment : urban layoffs and the way out in post-reform China (1993-1999) : an empirical and theoretical analysis

• In the literature, there are several terms that are used to designate persons who are laid off, such as layoffs, retrenched workers, off-duty workers, left-post workers etc., which is in Chinese ‘ xia gang zhi gong ’. The author prefer to use the term ‘ layoffs ’ in this paper, which seems to be consistent with other international studies. The Institute of Social Studies is Europe's longest-established centre of higher education and research in development studies. Post-graduate teaching programmes range from six-week diploma courses to the PhD programme. Research at ISS is fundamental in the sense of laying a scientific basis for the formulation of appropriate development policies. The academic work of ISS is disseminated in the form of books, journal articles, teaching texts, monographs and working papers. The Working Paper series provides a forum for work in progress which seeks to elicit comments and generate discussion. The series includes the research of staff, PhD participants and visiting fellows, and outstanding research papers by graduate students. For further information contact

A pQCD-based description of heavy and light flavor jet quenching

We present a successful description of the medium modification of light and heavy flavor jets within a perturbative QCD (pQCD) based approach. Only the couplings involving hard partons are assumed to be weak. The effect of the medium on a hard parton, per unit time, is encoded in terms of three non-perturbative, related transport coefficients which describe the transverse momentum squared gained, the elastic energy loss and diffusion in elastic energy transfer. A fit of the centrality dependence of the suppression and the azimuthal anisotropy of leading hadrons tends to favor somewhat larger transport coefficients for heavy quarks. Imposing additional constraints based on leading order (LO) Hard Thermal Loop (HTL) effective theory, leads to a worsening of the fit.Comment: v2, 4 pages, 3 figure

Joint radio resource management based on the species competition model

For optimal radio resource utilization in heterogeneous wireless networks, Joint Radio Resource Management (JRRM) is required. In distributed JRRM, each radio each access network (RAN) adjusts network parameters to affect user's RAN selection, thereby indirectly implementing joint radio resource allocation. The mathematical method for instructing such adjustment is lacking. In this article, the relationship between different RANs is mapped into the competition between species in the well-known L-V model developed by ecologists. Based on this model, an adjustment algorithm of distributed joint radio resource allocation is proposed. The simulation results show that compared with no adjustment or over adjustment, our adjustment algorithm can: 1) obtain proper resource allocation; 2) guarantee network coexistence. ©2006 IEEE.published_or_final_versio

Testing a new luminosity/redshift indicator for γ\gamma-ray bursts

We have tested a relative spectral lag (RSL) method suggested earlier as a luminosity/redshift (or distance) estimator, using the generalized method by Schaefer & Collazzi. We find the derivations from the luminosity/redshift-RSL (L/R-RSL) relation are comparable with the corresponding observations. Applying the luminosity-RSL relation to two different GRB samples, we find that there exist no violators from the generalized test, namely the Nakar & Piran test and Li test. We also find that about 36 per cent of Schaefer's sample are outliers for the L/R-RSL relation within 1$\sigma$ confidence level, but no violators at 3$\sigma$ level within the current precision of L/R-RSL relation. An analysis of several potential outliers for other luminosity relations shows they can match the L/R-RSL relation well within an acceptable uncertainty. All the coincident results seem to suggest that this relation could be a potential tool for cosmological study.Comment: 7 pages, 6 figures and 1 table; Comments are welcom

Newton-Hooke Limit of Beltrami-de Sitter Spacetime, Principles of Galilei-Hooke's Relativity and Postulate on Newton-Hooke Universal Time

Based on the Beltrami-de Sitter spacetime, we present the Newton-Hooke model under the Newton-Hooke contraction of the $BdS$ spacetime with respect to the transformation group, algebra and geometry. It is shown that in Newton-Hooke space-time, there are inertial-type coordinate systems and inertial-type observers, which move along straight lines with uniform velocity. And they are invariant under the Newton-Hooke group. In order to determine uniquely the Newton-Hooke limit, we propose the Galilei-Hooke's relativity principle as well as the postulate on Newton-Hooke universal time. All results are readily extended to the Newton-Hooke model as a contraction of Beltrami-anti-de Sitter spacetime with negative cosmological constant.Comment: 25 pages, 3 figures; some misprints correcte