Synthesis,characterization and antimicrobial screening of thiazole based 1,3,4-oxadiazoles heterocycles

Research on Chemical Intermediates - In an effort to find a new pharmacologically dynamic molecule, we report here the synthesis and in vitro antimicrobial activity of various...     

Effect of bulky substituents on the photochromic properties of indoline spiropyrans containing an annelated aromatic or heteroaromatic fragment

Novel indoline spiropyrans containing bulky neopentyl substituents at the nitrogen atom of the indoline fragment were prepared. The structure of the obtained compounds was established by a set of physicochemical methods of analysis. Comparison was made for the spectral absorption and kinetic parameters of the obtained compounds and their analogs containing methyl and benzyl substituents instead of neopentyl ones.     

Effect of environmental fluctuation on a detritus based ecosystem

Present paper deals with the stochastic perturbation analysis on a detritus based three dimensional food-chain in presence of gestation delays and recycling delay. We have perturbed some demographic parameters by white noise and coloured noise and then extensive numerical simulations are performed to understand the effect of fluctuating environment on the dynamics of the model system for different values of forcing intensities. We have explained how stochastic perturbation terms can be introduced in the model system. Mathematical analysis reveals the fact that the internal dynamics have no ability to suppress the environmental stochasticity and rhythmic oscillation does not persist in presence of environmental driving forces rather oscillate in a irregular fashion.     

On the Stein phenomenon under divergence loss and an unknown variance–covariance matrix

The paper develops a general class of shrinkage estimators for estimating the normal mean, which dominates the sample mean in three or higher dimensions under a general divergence loss. In the process, the earlier works of James and Stein [11] and Efron and Morris [5] are generalized considerably.     

Likelihood-based Inference for the Ratios of Regression Coefficients in Linear Models

We consider the standard linear multiple regression model in which the parameter of interest is the ratio of two regression coefficients. Our setup includes a broad range of applications. We show that the 1− α confidence interval for the interest parameter based on the profile, conditional profile, modified profile or adjusted profile likelihood can potentially become the entire real line, while appropriately chosen integrated likelihoods do not suffer from this drawback. We further explore the asymptotic length of confidence intervals in order to compare integrated likelihood-based proposals. The analysis is facilitated by an orthogonal parameterization.     

Stability and bifurcation in a diffusive prey-predator system: Non-linear bifurcation analysis

A stability analysis of a non-linear prey-predator system under the influence of one dimensional diffusion has been investigated to determine the nature of the bifurcation point of the system. The non-liner bifurcation analysis determining the steady state solution beyond the critical point enables us to determine characteristic features of the spatial inhomogeneous pattern arising out of the bifurcation of the state of the system.     

On a class of asymptotically optimal nonparametric tests for grouped data II

Summary In a previous paper [5], the author has proposed a class of asymptotically optimal (in the sense of Wald [11]) nonparametric tests for testing the hypothesis of no regression in a multiple linear regression model. In the present paper, we are interested in testing that the intercept in the multiple (linear) regression model is zero along with the absence of regression. A class of permutationally distribution-free tests has been proposed and their asymptotic optimality has been established. These results generalize analogus findings of Puri and Sen [9] for ungrouped data. As an important application, an alternative test to the problem of paired comparison has been considered. Research supported by National Institutes of Health, Institute of General Medical Sciences GM 12868-05.     

Critical behaviour of optical birefringence in the vicinity of nematic–isotropic and smectic A–isotropic phase transitions of the eight members of alkyloxy-cyanobiphenyls

We report the measurements of birefringence (Δn) as a function of the temperature of a homologous series of alkyloxy-cyanobiphenyls (nOCB) liquid crystalline compounds by means of high-resolution optical transmission method. The temperature dependence of the birefringence has been determined from the transmitted intensity data for two different wavelengths. The order parameter critical exponent β, obtained by using a four-parameter fitting procedure consistent with the mean-field theory for a weakly first order transition, is found to be in good agreement with the theoretically predicted tricritical value. A weak birefringence has been found to develop on approaching the clearing temperature, which is tentatively attributed to the formation of a small mesophase domain within the isotropic phase. This striking behaviour leads to a further quantification of the critical fluctuation close to the transition. Finally, the order character of the nematic–isotropic (N–I) and smectic A–isotropic (SmA–I) phase transitions have been assessed by using the birefringence data. The critical exponent α (usually assigned to the heat capacity) extracted from Δn data describes the critical nature of N–I and SmA–I transitions and strongly supports the tricritical nature of the same.     

Global regulation of individual decision making

Collective behavior of a group of individuals is studied. Each individual adopts one of two alternative decisions on the basis of a neural network bistable dynamical system. The parameters of this system are regulated by collective behavior of the group with the purpose to control the number of individuals with certain decision. It is shown how behavior of the group depends on the distribution of initial states of individuals before they begin the process of decision making. If this distribution is narrow, then it can be impossible to achieve a stable coexistence of two decisions, and oscillations in the number of individuals with given decisions are observed. Various implications of this theory are discussed. Copyright © 2016 John Wiley & Sons, Ltd.