S-wave and P-wave non-strange baryons in the potential model of QCD

In this paper, we study the nucleon energy spectrum in the ground-state (with orbital momentum L=0) and the first excited state (L=1). The aim of this study is to find the mass and mixing angles of excited nucleons using a potential model describing QCD. This potential is of the "Coulombian + linear" type and we take into account some relativistic effects, namely we use essentially a relativistic kinematic necessary for studying light flavors. By this model, we found the proton and $\Delta (1232)$ masses respectively equal to ($968MeV$, $1168MeV$), and the masses of the excited states are between $1564MeV$ and $1607MeV$.Comment: 26 pages, 1 figur

(Field) Symmetrization Selection Rules

QCD and QED exhibit an infinite set of three-point Green's functions that contain only OZI rule violating contributions, and (for QCD) are subleading in the large N_c expansion. The Green's functions describe the ``decay'' of a J^{PC}={1,3,5 ...}^{-+} exotic hybrid meson current to two J=0 (hybrid) meson currents with identical P and C. We prove that the QCD amplitude for a neutral hybrid {1,3,5 ...}^{-+} exotic current to create eta pi0 only comes from OZI rule violating contributions under certain conditions, and is subleading in N_c.Comment: 20 pages, LaTeX. Two postscript figures. Final published versio

CARACTERISTIQUES EPIDEMIOLOGIQUES DU NEUROBLASTOME DANS UN SERVICE DE PEDIATRIE

Introduction : Le neuroblastome est la tumeur maligne solide extra-cérébrale la plus fréquente du jeune enfant. Cette tumeur se caractérise par une extrême variabilité clinique et évolutive, allant de la régression spontanée sans traitement à la progression rapidement fatale, malgré une chimiothérapie intensive. L’Objectif de ce travail est de décrire le profil épidémiologique, les aspects cliniques et paracliniques des cas de neuroblastome hospitalisés aux service de pédiatrie du CHU Tizi Ouzou.Matériel et méthode : Notre étude est rétrospective descriptive étalée sur une période de 4 ans, et nous avons recensés 13 cas de neuroblastome.Résultats : L’âge médian des patients était de 02 ans et demi. Le Sex ratio était de 5.5 M/F. Le neuroblastome abdominal représentait 77 % de l’ensemble des neuroblastomes. 80 % de ces derniers étaient de localisation surrénalienne. Il existait une prédilection pour le côté gauche. Aucune forme cervicale n’a été retrouvée. La masse abdominale était le signe révélateur le plus fréquent dans notre étude avec 77 % des cas. Biologiquement, 69,2 % de nos patients ont eu un taux élevé de catécholamines urinaires. La scintigraphie à la MIBG avait montré une localisation osseuse secondaire chez 7 cas. L’échographie abdomino-pelvienne avait révélé des anomalies dans 92 % des cas chez nos patients. L’aspect le plus fréquent était une masse rétropéritonéale latéro-vertébrale, extra-rénale. Selon la classification TNM, les malades étaient au stade IV dans 53,8 % cas.Conclusion : Les données de cette étude et sa comparaison aux études recensée dans la littérature, montre que le profil général du neuroblastome reste approximativement similaire. Le diagnostic précoce grâce à une connaissance adéquate des symptômes révélateur et la stadification correcte restent les clés d’une meilleure approche thérapeutique

Hybrid Decays

The heavy quark expansion of Quantum Chromodynamics and the strong coupling flux tube picture of nonperturbative glue are employed to develop the phenomenology of hybrid meson decays. The decay mechanism explicitly couples gluonic degrees of freedom to the pair produced quarks and hence does not obey the well known, but model-dependent, selection rule which states that hybrids do not decay to pairs of L=0 mesons. However, the nonperturbative nature of gluonic excitations in the flux tube picture leads to a new selection rule: light hybrids do not decay to pairs of identical mesons. New features of the model are highlighted and partial widths are presented for several low lying hybrid states.Comment: 13 pages, 1 table, revte

The hybrid meson: new results from the updated mg and alpha_s parameters

We present new results concerning the masses and the decay widths of the most interesting hybrid meson states taking as inputs the gluon mass mg and the non-perturbative QCD running coupling constant ?alpha_s(0) comming from both LQCD and SDE recent estimations.Comment: 10 pages, 8 table

Cell-Free DNA as a Diagnostic and Prognostic Biomarker in Pediatric Rhabdomyosarcoma.

PURPOSE: Total cell-free DNA (cfDNA) and tumor-derived cfDNA (ctDNA) can be used to study tumor-derived genetic aberrations. We analyzed the diagnostic and prognostic potential of cfDNA and ctDNA, obtained from pediatric patients with rhabdomyosarcoma. METHODS: cfDNA was isolated from diagnostic plasma samples from 57 patients enrolled in the EpSSG RMS2005 study. To study the diagnostic potential, shallow whole genome sequencing (shWGS) and cell-free reduced representation bisulphite sequencing (cfRRBS) were performed in a subset of samples and all samples were tested using droplet digital polymerase chain reaction to detect methylated RASSF1A (RASSF1A-M). Correlation with outcome was studied by combining cfDNA RASSF1A-M detection with analysis of our rhabdomyosarcoma-specific RNA panel in paired cellular blood and bone marrow fractions and survival analysis in 56 patients. RESULTS: At diagnosis, ctDNA was detected in 16 of 30 and 24 of 26 patients using shallow whole genome sequencing and cfRRBS, respectively. Furthermore, 21 of 25 samples were correctly classified as embryonal by cfRRBS. RASSF1A-M was detected in 21 of 57 patients. The presence of RASSF1A-M was significantly correlated with poor outcome (the 5-year event-free survival [EFS] rate was 46.2% for 21 RASSF1A-M‒positive patients, compared with 84.9% for 36 RASSF1A-M‒negative patients [P < .001]). RASSF1A-M positivity had the highest prognostic effect among patients with metastatic disease. Patients both negative for RASSF1A-M and the rhabdomyosarcoma-specific RNA panel (28 of 56 patients) had excellent outcome (5-year EFS 92.9%), while double-positive patients (11/56) had poor outcome (5-year EFS 13.6%, P < .001). CONCLUSION: Analyzing ctDNA at diagnosis using various techniques is feasible in pediatric rhabdomyosarcoma and has potential for clinical use. Measuring RASSF1A-M in plasma at initial diagnosis correlated significantly with outcome, particularly when combined with paired analysis of blood and bone marrow using a rhabdomyosarcoma-specific RNA panel