Propagators on the two-dimensional light-cone

Light-cone quantization procedure recently presented is applied to the two-dimensional light-cone theories. By introducing the two distinct null planes it is shown that the modification term in the two-dimensional massless light-cone propagators suggested about twenty years ago vanishs.Comment: LATEX, 9page

Quantum effects of a massive 3-form coupled to a Dirac field

We consider the coupling of A_{\mu\nu\rho} to the generic current of matter field, later identified with the spin density current of a Dirac field. In fact, one of the objectives of this paper is to investigate the impact of the quantum fluctuations of A_{\mu\nu\rho} on the effective dynamics of the spinor field. The consistency of the field equations, even at the classical level, requires the introduction of a mass term for A_{\mu\nu\rho}. In this case, the Casimir vacuum pressure includes a contribution that is explicitly dependent on the mass of A_{\mu\nu\rho} and leads us to conclude that the mass term plays the same role as the infrared cutoff needed to regularize the finite volume partition functional previously calculated in the massless case. Remarkably, even in the presence of a mass term, A_{\mu\nu\rho} contains a mixture of massless and massive spin-0 fields so that the resulting equation is still gauge invariant. This is yet another peculiar, but physically relevant property of A_{\mu\nu\rho} since it is reflected in the effective dynamics of the spinor fields and confirms the confining property of A_{\mu\nu\rho} already expected from the earlier calculation of the Wilson loop.Comment: 10 pages, Revtex, no figures; in print on Phys.Rev.D; added new reference

Selberg Supertrace Formula for Super Riemann Surfaces III: Bordered Super Riemann Surfaces

This paper is the third in a sequel to develop a super-analogue of the classical Selberg trace formula, the Selberg supertrace formula. It deals with bordered super Riemann surfaces. The theory of bordered super Riemann surfaces is outlined, and the corresponding Selberg supertrace formula is developed. The analytic properties of the Selberg super zeta-functions on bordered super Riemann surfaces are discussed, and super-determinants of Dirac-Laplace operators on bordered super Riemann surfaces are calculated in terms of Selberg super zeta-functions.Comment: 43 pages, amste

Some Results on Cubic and Higher Order Extensions of the Poincar\'e Algebra

In these lectures we study some possible higher order (of degree greater than two) extensions of the Poincar\'e algebra. We first give some general properties of Lie superalgebras with some emphasis on the supersymmetric extension of the Poincar\'e algebra or Supersymmetry. Some general features on the so-called Wess-Zumino model (the simplest field theory invariant under Supersymmetry) are then given. We further introduce an additional algebraic structure called Lie algebras of order F, which naturally comprise the concepts of ordinary Lie algebras and superalgebras. This structure enables us to define various non-trivial extensions of the Poincar\'e algebra. These extensions are studied more precisely in two different contexts. The first algebra we are considering is shown to be an (infinite dimensional) higher order extension of the Poincar\'e algebra in $(1+2)-$dimensions and turns out to induce a symmetry which connects relativistic anyons. The second extension we are studying is related to a specific finite dimensional Lie algebra of order three, which is a cubic extension of the Poincar\'e algebra in $D-$space-time dimensions. Invariant Lagrangians are constructed.Comment: Mini course given at the Workshop higher symmetries in physics, Madrid, Spain, November 6-8, 200

Cortactin expression predicts poor survival in laryngeal carcinoma

Amplification of the 11q13 region is one of the most frequent aberrations in squamous cell carcinomas of the head and neck region (HNSCC). Amplification of 11q13 has been shown to correlate with the presence of lymph node metastases and decreased survival. The 11q13.3 amplicon carries numerous genes including cyclin D1 and cortactin. Recently, we reported that FADD becomes overexpressed upon amplification and that FADD protein expression predicts for lymph node positivity and disease-specific mortality. However, the gene within the 11q13.3 amplicon responsible for this correlation is yet to be identified. In this paper, we compared, using immunohistochemical analysis for cyclin D1, FADD and cortactin in a series of 106 laryngeal carcinomas which gene correlates best with lymph node metastases and increased disease-specific mortality. Univariate Cox regression analysis revealed that high expression of cyclin D1 (P=0.016), FADD (P=0.003) and cortactin (P=0.0006) predict for increased risk to disease-specific mortality. Multivariate Cox analysis revealed that only high cortactin expression correlates with disease-specific mortality independent of cyclin D1 and/or FADD. Of genes located in the 11q13 amplicon, cortactin expression is the best predictor for shorter disease-specific survival in late stage laryngeal carcinomas

The state of HRM in the Middle East:Challenges and future research agenda

Based on a robust structured literature analysis, this paper highlights the key developments in the field of human resource management (HRM) in the Middle East. Utilizing the institutional perspective, the analysis contributes to the literature on HRM in the Middle East by focusing on four key themes. First, it highlights the topical need to analyze the context-specific nature of HRM in the region. Second, via the adoption of a systematic review, it highlights state of development in HRM in the research analysis set-up. Third, the analysis also helps to reveal the challenges facing the HRM function in the Middle East. Fourth, it presents an agenda for future research in the form of research directions. While doing the above, it revisits the notions of “universalistic” and “best practice” HRM (convergence) versus “best-fit” or context distinctive (divergence) and also alternate models/diffusion of HRM (crossvergence) in the Middle Eastern context. The analysis, based on the framework of cross-national HRM comparisons, helps to make both theoretical and practical implications

11q13 amplification status and human papillomavirus in relation to p16 expression defines two distinct etiologies of head and neck tumours

Two distinct etiologies of head and neck squamous cell carcinoma (HNSCC) have been proposed, DNA damage owing to tobacco and alcohol exposure and human papillomavirus (HPV) oncogene-mediated transformation. Common genetic alterations in HNSCC include TP53 mutations, 11q13 amplification (amp) and CDKN2A/p16 mutations or promoter methlyation. However, in HPV+ HNSCC it is frequent to observe wild-type TP53 and expression of p16. The relationship of this unusual pattern with 11q13 amp has not been tested. In a retrospective study on 125 HNSCC patients, only 17% (five out of 30) of HPV+ vs 44% (39 out of 89) of HPV − tumours expressed 11q13 amp (adjusted odds ratio (OR)=0.2, 95% confidence interval (CI)=0.1–0.6). A subpopulation of tumours (n=69) were classified according to the three molecular markers, TP53, p16 and 11q13 amp. In addition to wild-type TP53, and p16 expression, HPV+ tumours were more likely not to be amplified at 11q13 (OR=6.5, 95% CI=1.8–23.9). As HPV+ HNSCC lack the genetic alterations which are common in other tumours, we hypothesise that HPV infection may represent an early event in the HNSCC carcinogenic process, thus suggesting a distinct molecular pathway