Particle states of Lattice QCD

We determine the degeneracy factor and the average particle mass of particles that produce the Lattice QCD pressure and specific entropy at zero baryon chemical potential. The number of states of the gluons and the quarks are found to converge above $T=$230 MeV to almost constant values, close to the number of states of an ideal Quark-Gluon Phase, while their assigned masses retain high values. The number of states and the average mass of a system containing quarks in interaction with gluons are found to decrease steeply with increase of temperature between $T \sim 150$ and 160 MeV, a region contained within the region of the chiral transition. The minimum value of the number of states within this temperature interval indicates that the states are of hadronic nature.Comment: 21 pages, 18 figure

The strange-quark chemical potential as an experimentally accessible "order parameter" of the deconfinement phase transition for finite baryon-density

We consider the change of the strange-quark chemical potential in the phase diagram of nuclear matter, employing the Wilson loop and scalar quark condensate order parameters, mass-scaled partition functions and enforcing flavor conservation. Assuming the region beyond the hadronic phase to be described by massive, correlated and interacting quarks, in the spirit of lattice and effective QCD calculations, we find the strange-quark chemical potential to change sign: from positive in the hadronic phase - to zero upon deconfinement - to negative in the partonic domain. We propose this change in the sign of the strange-quark chemical potential to be an experimentally accessible order parameter and a unique, concise and well-defined indication of the quark-deconfinement phase transition in nuclear matter.Comment: 22 pages, 14 figures within text, 2 figures(6,B3) as separate files. To be published in J.Phys.G: Nucl.&Part.Phys. G28 (2002

A study of the entanglement in systems with periodic boundary conditions

We define the local periodic linking number, LK, between two oriented closed or open chains in a system with three-dimensional periodic boundary conditions. The properties of LK indicate that it is an appropriate measure of entanglement between a collection of chains in a periodic system. Using this measure of linking to assess the extent of entanglement in a polymer melt we study the effect of CReTA algorithm on the entanglement of polyethylene chains. Our numerical results show that the statistics of the local periodic linking number observed for polymer melts before and after the application of CReTA are the same.Comment: 11 pages, 11 figure

Model of Centauro and strangelet production in heavy ion collisions

We discuss the phenomenological model of Centauro event production in relativistic nucleus-nucleus collisions. This model makes quantitative predictions for kinematic observables, baryon number and mass of the Centauro fireball and its decay products. Centauros decay mainly to nucleons, strange hyperons and possibly strangelets. Simulations of Centauro events for the CASTOR detector in Pb-Pb collisions at LHC energies are performed. The signatures of these events are discussed in detail.Comment: 19 pages, LaTeX+revtex4, 14 eps-figures and 3 table

Acute bacterial meningitis in adults

Over the past several decades, the incidence of bacterial meningitis in children has decreased but there remains a significant burden of disease in adults, with a mortality of up to 30%. Although the pathogenesis of bacterial meningitis is not completely understood, knowledge of bacterial invasion and entry into the CNS is improving. Clinical features alone cannot determine whether meningitis is present and analysis of cerebrospinal fluid is essential for diagnosis. Newer technologies, such as multiplex PCR, and novel diagnostic platforms that incorporate proteomics and genetic sequencing, might help provide a quicker and more accurate diagnosis. Even with appropriate antimicrobial therapy, mortality is high and so attention has focused on adjunctive therapies; adjunctive corticosteroids are beneficial in certain circumstances. Any further improvements in outcome are likely to come from either modulation of the host response or novel approaches to therapy, rather than new antibiotics. Ultimately, the best hope to reduce the disease burden is with broadly protective vaccines

Ethical and practical challenges in implementing informed consent in HIV/AIDS clinical trials in developing or resource-limited countries

Background/rationale: Ethical issues regarding HIV/AIDS human research in the developing world remain under continuous evaluation; a critical area of concern includes informed consent. This paper reviews several of the most important ethical and practical aspects of informed consent in HIV research in developing countries. Enhancement of overall understanding of such key issues might promote higher ethical standards of future research.Objectives: The major objective was to address informed consent in human research in non-Western societies, and specifically in HIV clinical trials of affected adults. Secondary end-points included the consent complexities in HIV research involving vulnerable patient populations in resource-limited nations, such as children, adolescents and women.Methods: A systematic review of the published literature using MEDLINE and EMBASE from 1998 until December 2008 was performed, using the search terms ‘HIV/AIDS’, ‘informed consent’, ‘clinical trials’, ‘developing world’.Results: Ethical complexities such as participants’ diminished autonomy, coercion or monetary inducement, language difficulties, illiteracy or lack of true understanding of the entire study, cultural barriers mainly due to communitarianism and social diversities were identified in the 44 studies reviewed. Informed consent of vulnerable patient populations must be tailored to their sex and developmental age, while counselling is fundamental. Children and adolescents’ assent must be ensured. Local language is to be used, while trusted community leaders and local cultural representatives may convey information.Discussion: Despite the heterogeneity of studies, similarities were  identified. Providing adequate and comprehensive information and assessing the true understanding of the research represent fundamental prerequisites. Potential solutions to the critical areas of concern include peer counselling and meetings with local community leaders or local cultural representatives. Conclusions: International investigators of HIV human research should bear in mind these ethical issues and their potential solutions, when trying to ensure ethical research conduct, based on a truly informed and culturally relevant consent

Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment

We present a phenomenological model which describes the formation of a Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and at the LHC, and its decay to non-strange baryons and Strangelets. We describe the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta < 7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations for the response of the CASTOR calorimeter, and in particular to the traversal of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR