Grouped random effects models for Bayesian meta-analysis

Meta-analysis refers to quantitative methods to combine results from independent studies so as to draw overall conclusions. Frequently, results from dissimilar studies are inappropriately combined, resulting in suspect inferential synthesis. We present a straightforward method to identify and address this problem through the development of grouped random effect models for meta-analysis. We examine 15 comparative studies that investigate the efficacy of a new anti-epileptic drug, progabide. The flexibility of this modelling scheme is exemplified by the result that the open studies support the efficacy of progabide while the closed studies support the reverse hypothesis. Bayesian approaches for meta-analysis are preferable because of the small number of studies prevalent in meta-analysis. We specify diffuse proper prior and hyperprior distributions to assure posterior propriety. We investigate sensitivity of the posterior to choice of prior. We use Gibbs sampling and the Metropolis algorithm to generate samples from the relevant posteriors. We analyse posterior summaries and plots of model parameters to suggest solutions to questions of interest.     

Elimination of the adverse effects of small model features by the local modification of automatically generated meshes

Issues related to the automated identification and elimination of the adverse influence of small geometric model features on the quality of automatically generated meshes, using local mesh modification operators, are addressed. The definition of mesh validity with respect to the geometric model is extended to include multiple mesh entity classifications. Checks based on mesh topology are used to ensure no dimensional reductions in the locally modified mesh. Example geometric models of varied complexity containing small geometric features are used to demonstrate the ability of presented procedures to improve mesh quality in terms of aspect ratio and small angle metrics.     

Sediment Threshold with Upward Seepage

An analytical model is presented to determine the threshold bed shear stress for noncohesive sediment motion subject to upward seepage on horizontal sedimentary bed under a stream flow. Hydrodynamic, seepage, and micromechanical forces acting on a solitary sediment particle, resting over a sedimentary bed under slip-spinning condition, are analyzed. The correlation coefficient between the results obtained using the present model and the experimental data of threshold bed shear stress with upward seepage on the horizontal bed is 0.767. It indicates that the model predicts satisfactorily the threshold bed shear stress with upward seepage.     

A new customized document categorization scheme using rough membership

One of the problems that plague document ranking is the inherent ambiguity, which arises due to the nuances of natural language. Though two documents may contain the same set of words, their relevance may be very different to a single user, since the context of the words usually determines the relevance of a document. Context of a document is very difficult to model mathematically other than through user preferences. Since it is difficult to perceive all possible user interests a priori and install filters for the same at the server side, we propose a rough-set-based document filtering scheme which can be used to build customized filters at the user end. The documents retrieved by a traditional search engine can then be filtered automatically by this agent and the user is not flooded with a lot of irrelevant material. A rough-set-based classificatory analysis is used to learn the user's bias for a category of documents. This is then used to filter out irrelevant documents for the user. To do this we have proposed the use of novel rough membership functions for computing the membership of a document to various categories.     

Heat conduction in bismuth-antimony alloy single crystals between 4.2 and 300 K

Thermal conductivity measurements in the temperature range 4.2–300 K on three single crystals of bismuth containing 1.77, 3.2, and 9.33 at % antimony, respectively, are reported. In the low-temperature region, a change from purely phonon-phonon scattering process to a predominantly impurity scattering process was observed with the increase of antimony concentration. In the high-temperature region, the analysis of the results shows the dominance of the electronic contribution over the phonon contribution to the total thermal conductivity, though the latter is not negligible. Individual contributions to total electronic thermal conductivity were calculated, using the equation formulated by Price, for the sample containing 9.33 at % antimony. The agreement between (K _E)_calc and (K _E)_exp = K ? K_L seems to be quite satisfactory up to about 200 K.     

Higher order finite strip analysis for curved bridge decks

The development of a higher order finite strip method for improved accuracy and its application to orthotropic curved bridge decks are discussed. A quintic polynomial in the radial direction is employed along with a basic function series in the angular direction which satisfy a priori the boundary conditions along the radial edges. Thus a two-dimensional plate bending problem is reduced to a one-dimensional one. As a result, both the size and bandwidth of the global stiffness matrix are greatly reduced. The method is easy to program, requires a minimum input data and small computer storage. In order to estimate the reliability of the present formulation, three examples of curved plates are solved and the results are compared with the existing solutions.     

Detection of Helicobacter pylori associated antigen and heat shock protein 60 on follicular dendritic cells in the germinal centres of low grade B cell lymphoma of gastric mucosa associated lymphoid tissue (MALT)

AIMS: To investigate the localisation of Helicobacter pylori antigens and the expression of human heat shock proteins (HSP) in stomachs affected by MALT lymphoma. METHODS: Surgically resected stomachs from 24 patients with MALT lymphoma were immunostained with anti-H pylori rabbit antibodies (ORP-1 and ORP-2) and anti-human HSP60 mouse monoclonal antibodies (mAb) (LK-1 and LK-2). RESULTS: Follicular dendritic cells of germinal centres in the stomachs affected by MALT lymphoma were immunostained with anti-H pylori polyclonal antibodies and with anti-human HSP60 mAb, as were the epithelial cells. None of the lymph node samples reacted. CONCLUSIONS: Human HSP60, which cross reacts with anti-H pylori polyclonal antibodies, is often expressed on follicular dendritic cells in gastric MALT lymphoma tissues and may be aetiologically relevant to lymphomagenesis of MALT lymphoma.     

S.E.M. studies of the Li-film growth and the voltage-delay phenomenon associated with the lithium-thionyl chloride inorganic electrolyte system

The “voltage-delay” exhibited by the Li/SOCl₂ inorganic electrolyte cells has been determined to be due to the Li anode which presumably reacts with the soluble depolarizer SOCl₂ and forms a protective film. The morphology and the growth of the Li film have been studied at temperatures of 25°, 45°, 55°, 70° and 85°C employing S.E.M. The results show that Li is coated with LiCi crystals formed due to the chemical reaction between Li and inorganic electrolyte (LiAlCl₄-SOCl₂). The LiCl film (many microns thick) grows with time and temperature of storage resulting in the voltage delay. The voltage recovery appears to occur due to the mechanical disruption of the film during the anodic dissolution of Li from under the film at isolated spots. The Li film growth is significantly reduced in the absence of LiAlCl₄ in SOCl₂.     

Fatty acid compositions of indian shark liver fats

Summary Liver fats ofCarcharias limbatus andPristis cuspidatus from the West Coast of India have been studied. Lithium salt-acetone and lead salt-alcohol methods were adopted for the resolution of the fatty acids. An efficient, electrically heated and packed column has been employed for fractionation of the methyl esters of fatty acids. These fats have been found to have a high content of saturated fatty acids and thus belong to the fourth group of Tsujimoto's classification of Elasmobranch fish liver fats. Analyses of the liver oils from the same species of fish show that there is a tendeney towards saturation or hydrogenation of polyethylenic acids accompanied by an increasing concentration of unsaponifiable matter, which is mainly alcohol ethers of the selachyl type, in accordance with Lovern's views.