Glueball-glueball scattering in a constituent gluon model

In this work we use a mapping technique to derive in the context of a constituent gluon model an effective Hamiltonian that involves explicit gluon degrees of freedom. We study glueballs with two gluons using the Fock-Tani formalism. In the present work we consider two possibilities for $0^{++}$: (i) as a pure $s\bar{s}$ and calculate, in the context of a quark interchange picture, the cross-section; (ii) as a glueball where a new calculation for this cross-section is made, in the context of the constituent gluon model, with gluon interchange.Comment: Proceedings of the International Workshop IX Hadron Physics and VII Relativistic Aspects of Nuclear Physics (HADRON-RANP 2004

Meson decay in the Fock-Tani Formalism

The Fock-Tani formalism is a first principle method to obtain effective interactions from microscopic Hamiltonians. Usually this formalism was applied to scattering, here we introduced it to calculate partial decay widths for mesons.Comment: Presented at HADRON05 XI. "International Conference on Hadron Spectroscopy" Rio de Janeiro, Brazil, August 21 to 26, 200

Hypoxaemia on arrival in a multidisciplinary intensive care unit

Background. Transport of the critically ill patient poses the risk of numerous complications. Hypoxaemia is one such serious adverse event and is associated with potential morbidity and mortality. It is, however, potentially preventable.Objective. To determine the incidence of hypoxaemia on arrival in a tertiary multidisciplinary intensive care unit (ICU) and to identify risk factors for this complication.Method. A retrospective observational study was conducted at King Edward VIII Hospital, Durban, South Africa, from May 2013 to February 2014.Results. Hypoxaemia occurred in 15.5% of admissions sampled. Statistically significant risk factors for hypoxaemia on univariate analysis (p<0.05) included lack of peripheral capillary oxygen saturation (SpO2) monitoring, transfer by an intern as opposed to other medical/ paramedical staff, and transfer from internal medicine. Use of neuromuscular blockers and transfer from theatre were protective. Binary logistic regression analysis revealed lack of SpO2 monitoring to be the only significant independent predictor of hypoxaemia (odds ratio 6.1; 95% confidence interval 1.5 - 24.5; p=0.02).Conclusion. Hypoxaemia is common on admission to the ICU and may be prevented by simple interventions such as appropriate transport monitoring

Nonequilibrium Temperature and Thermometry in Heat-Conducting Phi-4 Models

We analyze temperature and thermometry for simple nonequilibrium heat-conducting models. We show in detail, for both two- and three-dimensional systems, that the ideal gas thermometer corresponds to the concept of a local instantaneous mechanical kinetic temperature. For the Phi-4 models investigated here the mechanical temperature closely approximates the local thermodynamic equilibrium temperature. There is a significant difference between kinetic temperature and the nonlocal configurational temperature. Neither obeys the predictions of extended irreversible thermodynamics. Overall, we find that kinetic temperature, as modeled and imposed by the Nos\'e-Hoover thermostats developed in 1984, provides the simplest means for simulating, analyzing, and understanding nonequilibrium heat flows.Comment: 20 pages with six figures, revised following review at Physical Review

Early catecholamine dose as a predictor of outcome among patients in a multidisciplinary intensive care unit

Background. Vasoactive and/or inotropic agents are used in the management of patients with circulatory shock. It is a clinical perception that mortality in critically ill patients increases with increasing doses of inotropes and/or vasopressors; however, the clinical significance of catecholamine doses early in the management of critically ill patients has not been investigated well, especially in the South African (SA) context. Arbitrary ‘maximum’ doses of catecholamine therapy are used that are not evidence based. This study will help clinicians by either showing that there is no clear cut-off beyond which survival is unlikely or by identifying a dose of inotropic support above which survival is unlikely. This article provides clinicians with an evidence base against which to direct their therapy.Objectives. To describe the inotropic prescribing practices in a heterogeneous population of shocked critically ill patients in a tertiary intensive care unit (ICU) in SA, establish an association between inotropic dose and outcome and ascertain the nature of this association.Methods. This was a retrospective observational study of 189 patients admitted to a multidisciplinary academic ICU. The admission, 24-hour and maximum inotrope doses were collected and analysed, and these and other biochemical and clinical parameters were evaluated as predictors of mortality.Results. A total of 189 patients met the study inclusion criteria. The overwhelming majority of patients (99%) received adrenaline, with only 7% of those requiring inotropes receiving noradrenaline. Median inotrope dose at admission, 24-hour dose and maximum dose in the first 24 hours were all significantly higher in non-survivors than survivors. ICU mortality increased with increasing inotrope dose, and an inotrope dose ≥60 μg/min on admission was associated with an ICU mortality of 89%, with the same cut-off at 24 hours being associated with a mortality of 89%. Survivors at doses >80 μg/min were only noted among trauma patients.Conclusions. High early inotrope doses are associated with increasing ICU mortality. The findings highlight the need for further research on the clinical use of inotrope dose in risk stratification in the critical care environment. The current results call into question the routine provision of high-dose inotropic support in non-trauma patients