Towards the Deconfinement Phase Transition in Hot Gauge Theories

The phase structure of hot gauge theories with dynamical matter fields is reexamined in the canonical ensemble with respect to triality. We discuss properties of chromoelectric and chromomagnetic sectors of the theory and show whereas electric charges carrying a unit of Z(N) charge are screened at high temperatures via dynamical matter loops, this is not the case for the Z(N) magnetic flux. An order parameter is constructed to probe the realization of local Z(N) symmetry in the magnetic sector. We argue this order parameter may be used to detect the deconfinement phase transition which is defined in terms of the screening mechanism.Comment: poster presented at LATTICE97; 3 pages, late

Deconfinement in QCD with dynamical quarks

We study the phase structure of full QCD within the canonical ensemble with respect to triality in a lattice formulation. The procedure for the calculation of the effective potentials in this case is given. As an example we consider the three dimensional SU(2) gauge model at finite temperatures in the strong coupling region. The potential exhibits a deconfinement phase transition unlike the similar potential obtained in the grand canonical ensemble which demonstrates explicit Z(N) symmetry breaking at any temperature. Furthermore, we investigate the effective potential with the chiral condensate included. In contradiction to other authors, we find chiral symmetry restoration in all triality sectors. In the scheme with massless staggered fermions we observe chiral symmetry restoration accompanying a deconfinement phase transition of first order. Above the critical point, besides two Z(2) symmetric "deconfining" vacua there exists a metastable "confining" vacuum in a wide region of parameters. Such a picture could be interpreted as an indication on a mixed state of hadrons and quarks in the vicinity of the critical line.Comment: 17 pages with 6 eps. figures include

Fresh look on triality

Investigating the $Z_3$ symmetry in Quantum Chromodynamics (QCD) we show that full QCD with a vacuum of vanishing baryonic number does not lead to metastable phases. Rather in QCD with dynamical fermions, the degeneracy of $Z_3$ phases manifests itself in observables without open triality.Comment: 9 pages, 0 figures, latex, IK-TUW-Preprint 930840

The M(BH)-Sigma Relation for Supermassive Black Holes

We investigate the differences in the M(BH)-sigma relation derived recently by Ferrarese & Merritt (2000) and Gebhardt et al. (2000). The shallower slope found by the latter authors (3.75 vs. 4.8) is due partly to the use of a regression algorithm that ignores measurement errors, and partly to the value of the velocity dispersion adopted for a single galaxy, the Milky Way. A steeper relation is shown to provide a better fit to black hole masses derived from reverberation mapping studies. Combining the stellar dynamical, gas dynamical, and reverberation mapping mass estimates, we derive a best-fit relation M(BH) = 1.30 (+/- 0.36) X 10^8 (sigma_c/200)^{4.72(+/- 0.36)}, where M(BH) is in solar masses, and sigma in km/s.Comment: The Astrophysical Journal, in pres

Nutritional Content and a Phase - I Safety Clinical Trial of a Herbal-Nutritional Supplement (Imuniti) With Putative Immune-Modulating Properties

The relationship between HIV and AIDS and poor nutrition has been well established. Poor nutrition hastens the progression of HIV infection to AIDS. The rising pandemic of HIV and AIDS and high toxicity associated with anti-retroviral use are major factors that have compelled research to explore traditional herbal medicines as potential alternatives or supplements to anti-retroviral agents. A Phase I clinical trial was conducted on IMUNITI Wellness Pack, a herbal product with putative immune-modulating properties. The product is a combination of 7 herbal preparations, minerals, vitamins, and a specially formulated soya-maize meal porridge and a bottle of water purifier. The aim was to evaluate the safety and tolerability of IMUNITI, with a purpose of developing it for use in HIV-infected patients. The phase I study was conducted at the MRC clinic in Botha’s hill and the study lasted 5 weeks from date of participant dosing. The study was a randomised blinded placebocontrolled phase I clinical trial conducted on 48 healthy males. The participants were randomly divided into 4 groups of 12. The 3 groups received different escalating doses of IMUNITI while the forth group received placebo tablets. Participants consumed IMUNITI daily for a period of 5 weeks. Assessments were done at baseline, week 1 and week 5 to determine the safety parameters in all participants. In this study, IMUNITI did not show any safety concerns. In all study participants, there were no significant changes above the upper limit of the reference ranges of the laboratory tests for full blood count, INR, renal and biochemical safety parameters. IMUNITI was well tolerated. Furthermore, the nutritional content analysis of IMUNITI showed that it is a high kilojoule, high protein content product which contains a mixture of sugars, vitamins, traces of calcium, phosphorus and minerals.Key words: HIV and AIDS, Immune booster, herbal product, traditional medicine

Static SU(3) potentials for sources in various representations

The potentials and string tensions between static sources in a variety of representations (fundamental, 8, 6, 15-antisymmetric, 10, 27 and 15-symmetric) have been computed by measuring Wilson loops in pure gauge SU(3). The simulations have been done primarily on anisotropic lattices, using a tadpole improved action improved to O(a_{s}^4). A range of lattice spacings (0.43 fm, 0.25 fm and 0.11 fm) and volumes ($8^3\times 24$, $10^3 \times 24$, $16^3 \times 24$ and $18^3 \times 24$) has been used in an attempt to control discretization and finite volume effects. At intermediate distances, the results show approximate Casimir scaling. Finite lattice spacing effects dominate systematic error, and are particularly large for the representations with the largest string tensions.Comment: Version to appear in PR

On the relevance of center vortices to QCD

In a numerical experiment, we remove center vortices from an ensemble of lattice SU(2) gauge configurations. This removal adds short-range disorder. Nevertheless, we observe long-range order in the modified ensemble: confinement is lost and chiral symmetry is restored (together with trivial topology), proving that center vortices are responsible for both phenomena. As for the Abelian monopoles, they survive but their percolation properties are lost.Comment: 4 pages, 5 figures; discussion expanded, text compressed... to appear in Phys. Rev. Let