Isothermal transient current studies in cellulose acetate films

Step voltage transient current studies have been made in cellulose acetate films as a function of filed and thickness. A logarithmic plot (Scherr-Montroll plot) of the transient current vs. time gives a knee at a time t_T, which is interpreted as the transit time of the charge carrier. The value of the carrier mobility has been estimated to be 3.9 × 10^?9 cm².V^?1.S^?1 in cellulose acetate film. The carrier mobility in iodine-doped (2% w/w) cellulose acetate film has also been determined from Scher-Montroll plot and is found to be 3.3 × 10^?7 cm².V^?1.S^?1.     

An A Contrario Decision Method for Shape Element Recognition

Shape recognition is the field of computer vision which addresses the problem of finding out whether a query shape lies or not in a shape database, up to a certain invariance. Most shape recognition methods simply sort shapes from the database along some (dis-)similarity measure to the query shape. Their main weakness is the decision stage, which should aim at giving a clear-cut answer to the question: “do these two shapes look alike?” In this article, the proposed solution consists in bounding the number of false correspondences of the query shape among the database shapes, ensuring that the obtained matches are not likely to occur “by chance”. As an application, one can decide with a parameterless method whether any two digital images share some shapes or not.     

Heterogeneous distribution of glycinergic and GABAergic afferents on an identified central neuron

Age-related increases and decreases have been described in cortical dendritic neuropil. Here, we examine age-related changes in the basilar dendrites of supragranular pyramidal cells in human superior temporal gyrus (i.e., Wernicke's area) of left and right hemispheres. Tissue was obtained from 20 neurologically normal right-handers from 18-79 years: 10 males (Mage = 52.2 years; SDage = 17.4) and 10 females (Mage = 47.8; SDage = 20.5). In tissue prepared by a modified rapid Golgi technique, ten pyramidal cells were sampled from each hemisphere and evaluated according to the following parameters: total dendritic length, mean dendritic length, and dendritic segment count. Despite considerable interindividual variation, the data exhibited significant dendritic degeneration with aging. There was an age-related decrease in total dendritic length (r[20] = -0.44; P < 0.05) and especially in mean dendritic length (r[20] = -0.69; P < 0.001) with increasing age. Age-mean dendritic length correlations were negative for all segment orders and revealed a progressive decrease in segment length in more distal branches. The number of dendritic segments remained relatively stable across the age span sampled. The data also indicated that interhemispheric dendritic asymmetries decreased with age. Individuals under 50 years of age had significantly greater total dendritic length values in the left hemisphere. Interhemispheric dendritic differences were not significant in individuals over 50.     

Unsteady compressible 3-dimensional boundary-layer flow near an asymmetric stagnation point with mass transfer

The heat and mass transfer for unsteady laminar compressible boundary-layer flow, which is asymmetric with respect to a 3-dimensional stagnation point (i.e. for a jet incident at an angle on the body), have been studied. It is assumed that the free-stream velocity, wall temperature, and surface mass transfer vary arbitrarily with time and also that the gas has variable properties. The solution in the neighbourhood of the stagnation point has been obtained by series expansion in the longitudinal distance. The resulting partial differential equations have been solved numerically using an implicit finite-difference scheme. The results show that, in contrast with the symmetric flow, the maximum heat transfer does not occur at the stagnation point. The skin-friction and heat-transfer components due to asymmetric flow are only weakly affected by the mass transfer as compared to those components associated with symmetric flow. The variation of the wall temperature with time has a strong effect on the heat transfer component associated with the symmetric part of the flow. The skin friction and heat transfer are strongly affected by the variation of the density-viscosity product across the boundary layer. The skin friction responds more to the fluctuations of the free stream oscillating velocities than the heat transfer. The results have been compared with the available results and they are found to be in excellent agreement.