Drug and poison information - the Tygerberg experience

This report is based on an analysis of 6 411 consultations processed by the Tygerberg Phannacology and Toxicology Consultation Centre. Seventy-five per cent of the consultations were of a toxicological nature: 47% related to non-drug chemicals, 37% to drugs and 16% to plants and animals. Pesticides utilised in the home environment featured most pronrinently in the non-drug chemical group, while queries about paracetamol overdose topped the list in the drug group. The most frequent queries in the biological category concerned potentially poisonous plants. Twenty-five per cent of the consultations related to phannacotherapeutics.Most potentially toxic exposures to non-drug chemicals occurred in the household setting. Contrary to popular belief, few acute pesticide poisonings were encountered as a result of exposures during farnring activities. Another important finding was that there is a frustrating lack of reliable and readily available information in respect of potentially toxic ingredients contained in household and industrial preparations.The large nnmber of household exposures highlights the need for education in the safe storage and usage of non-drug chemicals. Legislation on the inclusion of basic toxicological information and warnings on labels of household and industrial non-drug chemical products should be considered. In addition, the Government should take responsibility for centralising information on all potentially toxic non-drug chemicals and make this information available to poison centres at all times. It is also imperative that more attention be given to the training of health care professionals in applied phannacokinetics and toxicology

Experimental properties of Bose-Einstein condensates in 1D optical lattices: Bloch oscillations, Landau-Zener tunneling and mean-field effects

We report experimental results on the properties of Bose-Einstein condensates in 1D optical lattices. By accelerating the lattice, we observed Bloch oscillations of the condensate in the lowest band, as well as Landau-Zener (L-Z) tunneling into higher bands when the lattice depth was reduced and/or the acceleration of the lattice was increased. The dependence of the L-Z tunneling rate on the condensate density was then related to mean-field effects modifying the effective potential acting on the condensate, yielding good agreement with recent theoretical work. We also present several methods for measuring the lattice depth and discuss the effects of the micromotion in the TOP-trap on our experimental results.Comment: 11 pages, 14 figure

Theoretical Analysis of a Large Momentum Beamsplitter using Bloch Oscillations

In this paper, we present the implementation of Bloch oscillations in an atomic interferometer to increase the separation of the two interfering paths. A numerical model, in very good agreement with the experiment, is developed. The contrast of the interferometer and its sensitivity to phase fluctuations and to intensity fluctuations are also calculated. We demonstrate that the sensitivity to phase fluctuations can be significantly reduced by using a suitable arrangement of Bloch oscillations pulses

Thermal and mechanical properties of W/Cu composite materials for ITER heat sink applications

One of the main challenges in the development of a fusion power plant is the adequate selection of the materials that will withstand the extreme conditions of temperature, load and radiation. Among those issues, the control of the heat removal by the divertor is critical, hence the highest heat load inside the reactor will be found in it. For this purpose, one solution proposed is a novel optimized water-cooled monoblock divertor consisting of W as plasma facing material and W/Cu composites as the baseline heat sink material. The attraction of these metal matrix composites in fusion applications is twofold: the W matrix provides the necessary strength of the composite at high temperatures, while Cu provides the required high thermal conductivity for efficient heat removal in the cooling system. In this context, the goal of this study is the characterization of W-Cu composite materials produced by means of liquid Cu infiltration of open porous W preforms. In order to achieve it, a new experimental device was set up to test the composites under high vacuum atmosphere while in the temperature range between 273 K and 1073 K. Tensile and fracture tests in three point bending configuration have been conducted in this temperature range and atmosphere. Additionally, micromechanical and physical characterization was also performed by means of micro and nanoindentation and High Temperature X-Ray Diffraction respectively

Generalized Species Sampling Priors with Latent Beta reinforcements

Many popular Bayesian nonparametric priors can be characterized in terms of exchangeable species sampling sequences. However, in some applications, exchangeability may not be appropriate. We introduce a {novel and probabilistically coherent family of non-exchangeable species sampling sequences characterized by a tractable predictive probability function with weights driven by a sequence of independent Beta random variables. We compare their theoretical clustering properties with those of the Dirichlet Process and the two parameters Poisson-Dirichlet process. The proposed construction provides a complete characterization of the joint process, differently from existing work. We then propose the use of such process as prior distribution in a hierarchical Bayes modeling framework, and we describe a Markov Chain Monte Carlo sampler for posterior inference. We evaluate the performance of the prior and the robustness of the resulting inference in a simulation study, providing a comparison with popular Dirichlet Processes mixtures and Hidden Markov Models. Finally, we develop an application to the detection of chromosomal aberrations in breast cancer by leveraging array CGH data.Comment: For correspondence purposes, Edoardo M. Airoldi's email is [email protected]; Federico Bassetti's email is [email protected]; Michele Guindani's email is [email protected] ; Fabrizo Leisen's email is [email protected]. To appear in the Journal of the American Statistical Associatio

Current in the light-front Bethe-Salpeter formalism II: Applications

We pursue applications of the light-front reduction of current matrix elements in the Bethe-Salpeter formalism. The normalization of the reduced wave function is derived from the covariant framework and related to non-valence probabilities using familiar Fock space projection operators. Using a simple model, we obtain expressions for generalized parton distributions that are continuous. The non-vanishing of these distributions at the crossover between kinematic regimes (where the plus component of the struck quark's momentum is equal to the plus component of the momentum transfer) is tied to higher Fock components. Moreover continuity holds due to relations between Fock components at vanishing plus momentum. Lastly we apply the light-front reduction to time-like form factors and derive expressions for the generalized distribution amplitudes in this model.Comment: 12 pages, 6 figures, RevTex

Bragg spectroscopy with an accelerating Bose-Einstein condensate

We present the results of Bragg spectroscopy performed on an accelerating Bose-Einstein condensate. The Bose condensate undergoes circular micro-motion in a magnetic TOP trap and the effect of this motion on the Bragg spectrum is analyzed. A simple frequency modulation model is used to interpret the observed complex structure, and broadening effects are considered using numerical solutions to the Gross-Pitaevskii equation.Comment: 5 pages, 3 figures, to appear in PRA. Minor changes to text and fig

Dynamical structure factor of the anisotropic Heisenberg chain in a transverse field

We consider the anisotropic Heisenberg spin-1/2 chain in a transverse magnetic field at zero temperature. We first determine all components of the dynamical structure factor by combining exact results with a mean-field approximation recently proposed by Dmitriev {\it et al}., JETP 95, 538 (2002). We then turn to the small anisotropy limit, in which we use field theory methods to obtain exact results. We discuss the relevance of our results to Neutron scattering experiments on the 1D Heisenberg chain compound ${\rm Cs_2CoCl_4}$.Comment: 13 pages, 14 figure