Project Tektite 1 - A multiagency 60 day saturated dive conducted by the United States Navy, the National Aeronautics and Space Administration, the Department of the Interior, and the General Electric Company Summary report

Underwater research in ocean floor habitat for 60 day evaluation of supporting facilities at Virgin Islands for Tektite 1 projec

Power-Law Wave Functions and Generalized Parton Distributions for Pion

We propose a model for generalized parton distributions of the pion based on the power-law ansatz for the effective light-cone wave function.Comment: 27 pages, Latex; Revised and Extended Version, to be published in Phys. Rev.

On Simulating Liouvillian Flow From Quantum Mechanics Via Wigner Functions

The interconnection between quantum mechanics and probabilistic classical mechanics for a free relativistic particle is derived in terms of Wigner functions (WF) for both Dirac and Klein-Gordon (K-G) equations. Construction of WF is achieved by first defining a bilocal 4-current and then taking its Fourier transform w.r.t. the relative 4-coordinate. The K-G and Proca cases also lend themselves to a closely parallel treatment provided the Kemmer- Duffin beta-matrix formalism is employed for the former. Calculation of WF is carried out in a Lorentz-covariant fashion by standard `trace' techniques. The results are compared with a recent derivation due to Bosanac.Comment: 9 pages, Latex; email: [email protected]

Universal description of S-wave meson spectra in a renormalized light-cone QCD-inspired model

A light-cone QCD-inspired model, with the mass squared operator consisting of a harmonic oscillator potential as confinement and a Dirac-delta interaction, is used to study the S-wave meson spectra. The two parameters of the harmonic potential and quark masses are fixed by masses of rho(770), rho(1450), J/psi, psi(2S), K*(892) and B*. We apply a renormalization method to define the model, in which the pseudo-scalar ground state mass fixes the renormalized strength of the Dirac-delta interaction. The model presents an universal and satisfactory description of both singlet and triplet states of S-wave mesons and the corresponding radial excitations.Comment: RevTeX, 17 pages, 7 eps figures, to be published in Phys. Rev.

Clinical relevance of circulating tumour cells in the bone marrow of patients with SCCHN

Background: Clinical outcome of patients with head and neck squamous cell carcinoma (SCCHN) depends on several risk factors like the presence of locoregional lymph node or distant metastases, stage, localisation and histologic differentiation of the tumour. Circulating tumour cells in the bone marrow indicate a poor prognosis for patients with various kinds of malignoma. The present study examines the clinical relevance of occult tumour cells in patients suffering from SCCHN. Patients and Methods: Bone marrow aspirates of 176 patients suffering from SCCHN were obtained prior to surgery and stained for the presence of disseminated tumour cells. Antibodies for cytokeratin 19 were used for immunohistochemical detection with APAAP on cytospin slides. Within a clinical follow-up protocol over a period of 60 months, the prognostic relevance of several clinicopathological parameters and occult tumour cells was evaluated. Results: Single CK19-expressing tumour cells could be detected in the bone marrow of 30.7% of the patients. There is a significant correlation between occult tumour cells in the bone marrow and relapse. Uni- and multivariate analysis of all clinical data showed the metastases in the locoregional lymph system and detection of disseminated tumour cells in the bone marrow to be statistically highly significant for clinical prognosis. Conclusion: The detection of minimal residual disease underlines the understanding of SCCHN as a systemic disease. Further examination of such cells will lead to a better understanding of the tumour biology, as well as to improvement of diagnostic and therapeutic strategies

Gluon Distribution Functions for Very Large Nuclei at Small Transverse Momentum

We show that the gluon distribution function for very large nuclei may be computed for small transverse momentum as correlation functions of an ultraviolet finite two dimensional Euclidean field theory. This computation is valid to all orders in the density of partons per unit area, but to lowest order in $\alpha_s$. The gluon distribution function is proportional to $1/x$, and the effect of the finite density of partons is to modify the dependence on transverse momentum for small transverse momentum.Comment: TPI--MINN--93--52/T, NUC--MINN--93--28/T, UMN--TH--1224/93, LaTex, 11 page

Model for SU(3) vacuum degeneracy using light-cone coordinates

Working in light-cone coordinates, we study the zero-modes and the vacuum in a 2+1 dimensional SU(3) gauge model. Considering the fields as independent of the tranverse variables, we dimensionally reduce this model to 1+1 dimensions. After introducing an appropriate su(3) basis and gauge conditions, we extract an adjoint field from the model. Quantization of this adjoint field and field equations lead to two constrained and two dynamical zero-modes. We link the dynamical zero-modes to the vacuum by writing down a Schrodinger equation and prove the non-degeneracy of the SU(3) vacuum provided that we neglect the contribution of constrained zero-modes.Comment: 22 pages, 5 figure

Masses of the physical mesons from an effective QCD--Hamiltonian

The front form Hamiltonian for quantum chromodynamics, reduced to an effective Hamiltonian acting only in the $q\bar q$ space, is solved approximately. After coordinate transformation to usual momentum space and Fourier transformation to configuration space a second order differential equation is derived. This retarded Schr\"odinger equation is solved by variational methods and semi-analytical expressions for the masses of all 30 pseudoscalar and vector mesons are derived. In view of the direct relation to quantum chromdynamics without free parameter, the agreement with experiment is remarkable, but the approximation scheme is not adequate for the mesons with one up or down quark. The crucial point is the use of a running coupling constant $\alpha_s(Q^2)$, in a manner similar but not equal to the one of Richardson in the equal usual-time quantization. Its value is fixed at the Z mass and the 5 flavor quark masses are determined by a fit to the vector meson quarkonia.Comment: 18 pages, 4 Postscript figure

Finiteness Conditions for Light-Front Hamiltonians

In the context of simple models, it is shown that demanding finiteness for physical masses with respect to a longitudinal cutoff, can be used to fix the ambiguity in the renormalization of fermions masses in the Hamiltonian light-front formulation. Difficulties that arise in applications of finiteness conditions to discrete light-cone quantization are discussed.Comment: REVTEX, 9 page