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Late Paleocene sedimentation in the pericratonic Kachchh Basin marks the initial marine transgression during the Cenozoic era. A 17 m thick sandstone-dominated succession, known as the clastic member (CM) of the Matanomadh Formation (MF), is exposed sporadically in the basin. Three facies associations are reconstructed in the succession in three different sections. Facies association-1 contains matrix-supported pebbly conglomerate facies, horizontally-laminated sandstone-mudstone alternation facies, hummocky- and swaley cross-bedded sandstone facies, wave-rippled sandstone facies and climbing ripple cross-laminated sandstone facies. This facies association developed between shoreface and foreshore zone under the influence of storms on a barrier ridge. Facies association-2 contains sigmoidal cross-bedded sandstone facies, sandstone-mudstone alternation facies, flaser-bedded sandstone facies, herringbone cross-bedded sandstone facies and tangential cross-bedded sandstone facies. This facies association possessing tidal bundles and herringbone cross-beds developed on a tidal flat with strong tidal influence. Facies association-3 comprises pebbly sandstone facies, horizontally-bedded sandstone facies, tangential cross-bedded sandstone facies exhibiting reactivation surfaces and tabular cross-bedded sandstone facies. This facies association represents sedimentation in a river-dominated estuary and reactivation surfaces and herringbone cross-beds indicating tidal influence. The bipolar paleocurrent pattern changes to unipolar up-section because of the change in the depositional currents from tidal to fluvial. The sedimentation took place in an open coast similar to the Korean coast. The presence of neap-spring tidal rhythmites further suggests that a semidiurnal system similar to the modern day Indian Ocean was responsible for the sedimentation. Here, the overall sequence developed during the transgressive phase where barrier ridge succession is succeeded by the tidal flat succession and the latter, in turn, is succeeded by the estuarine succession. This study resolves the most debated issue of initial marine transgression in the Kachchh Basin during the Cenozoic.

Cenozoic era was the turning point in the geological history of the Indian subcontinent when India experienced maximum isolation before it collided with Asia and there occurred a great mountain building activity shaping the Himalaya. In the Cenozoic era, the sedimentation commenced in the late Paleocene (∼57.9 Ma) in the pericratonic basins of the western India as well as the foreland basins of the Himalaya that marks the beginning of a major transgression on the Indian subcontinent. Till now, it is not sure whether this transgression was forced by tectonics or climate. We have interpreted that the primary driver for this transgression was the tectonics that marks the beginning of the India–Asia convergence. A major regression of similar magnitude occurred during latest middle Eocene (41.3–38.0 Ma) that corresponds to global sea-level fall. This regression is global and can be identified even in the Cenozoic basins developed within the African plate. It is interpreted that this regression was driven by the global cooling during latest middle Eocene/late Eocene possibly associated with the nucleation of the Antarctica ice-sheets coupled with the uplift of the Himalaya.

The one-dimensional models for catalytic converters are used to account for the reduction of pollutants like hydrocarbons (HC), carbon monoxide (CO) and nitric oxide (NO). The proposed model considers both gaseous as well as solid phase reactions of only one gas propylene that could possibly be occurring in the converter channels. Metal substrates were considered, as the better heat conducting solid material. The Runge–Kutta method and backward implicit schemes were employed to solve the coupled ordinary and partial differential equations.

The problem of gas absorption into a falling film reactor was studied in the case of an instantaneous reaction. A diffusion-convection-reaction model was developed taking momentum, mass and heat transfer effects into account. The performance of the model was examined for sulphonation of tridecylbenzene. The resultant equations were solved using a finite difference backward implicit scheme. The results indicated an increase in the axial temperature of the liquid film for a short distance from the reactor top and the predicted conversion was in close agreement with the experimental results.

A series of 5-[( N -substituted benzylidenylimino)amino]-2-oxo/thiobarbituric acids (3a–3h) have been synthesized by the condensation of 5-hydrazino-2-oxo/thiobarbituric acids (2a–2b) with various aromatic aldehydes. Cycloaddition of thioglycolic acid to 3a–3h , yielded 5-[(2′-substituted phenyl-4′-oxothiazolidin-3′-yl)amino]-2-oxo/thiobarbituric acids (4a–4h) . All these compounds were screened, in vivo, for their anticonvulsant activity and acute toxicity studies. Compounds 4f and 4g were found to be most potent compounds of this series and were compared with the reference drugs, phenytoin sodium, lamotrigine and sodium valproate. The structures of these compounds have been established by IR, 1 H NMR and mass spectroscopic data.

Sal (Shorea robusta) is an important forest tree species in north and north-eastern India. Large-scale plantations of this species have been raised there under taungya and coppice system of management. The conventional volume table prepared for high sal forest is referred to infer the volume of production of this species. Earlier workers have used aerial remote sensing data to develop volume tables of this species. In the present study a volume table for sal is developed based on remotely sensed satellite data using a regression technique. A two-step method was developed to estimate mean tree volume from satellite data. In step 1, mean crown diameter — an intermediate variable - was estimated from satellite data. In step 2, the estimated mean crown diameter was used to estimate the mean tree volume. Addition of age of the crop as an independent variable improved the predictive ability of the regression equation.

Despite the now widespread use of nonlinear estimators, their finite-sample properties have received very little attention in either the statistics or econometrics literature. We partially redress this problem by deriving and examining the second-order bias and mean squared error of a fairly wide class of nonlinear estimators which includes Nonlinear Least Squares, Maximum Likelihood, and many Generalized Method of Moments estimators as special cases. A number of examples are provided. The results from a Monte Carlo exercise demonstrate how the results can be applied for improved inferences.

This paper considers Zellner's two estimators in a seemingly unrelated regression equations (SURE) model. Efficiency properties of the two estimators are analyzed by asymptotic expansions and Monte Carlo experiments under non-normal disturbances. It is shown that the two estimators have the same efficiency up to the second-order terms of O(T − 1 2 ) , and that non-normality influences the rate of convergency to normality of the estimators.

In recent years considerable interest has developed in evaluation of alternative refrigerants to CFC12. This paper presents the transport properties of near-azeotropic ternary mixtures of HCFC22, HCFC124 and HFC152a of different composition, namely HCFC22/HCFC124/HFC152a (33/52/15),(53/34/13),(61/28/11) and (36/40/24) respectively, computed over a wide range of temperatures using estimation techniques. The properties are presented in graphical form. Further correlations have been developed to express each property as a function of temperature to facilitate their use in the design of refrigeration systems.

In this paper we have provided a general result on the higher-order approximate moments of the ratio of quadratic forms in the non-normal vector. The results for the normal case are then presented as a special case of this result. It is also indicated that the results for a large class of econometric estimators and test statistics can be obtained by using our general result.

This paper considers the choice of scalars characterizing the double k-class estimators of the coefficients in a linear regression model. We demonstrate the existence of a double k-class estimator that dominates the least squares and Stein-rule estimators and we give feasible values for the characterizing scalars which nearly minimize the risk of the estimator.

For estimating the coefficients in a linear regression model, the Stein-rule estimators are considered and their performance is studied according to the criterion of Pitman closeness. For this purpose, an asymptotic approximation for the criterion is derived and analyzed.

Determining the specification of a regression model according to the regressors' significance leads to a pre-test strategy. The exact sampling distribution of such a preliminary-test estimator is derived in this paper.

For the estimation of the mean μ of a normal population with unknown variance σ2, Searles (1964) provides the minimum mean squared (MMSE) estimator (1 + σ2/(nμ2))−1 x in the class of all estimators of the type x . This MMSE estimator however is not computable in practice if σ/μ is unknown. Srivastava (1980) showed that the corresponding computable estimator t = (1 + s2/(n x 2)) x is more efficient than the usual estimator x whenever σ2/(nμ2) is at least 0.5. However, the gain in efficiency is a function of μ and σ2, and therefore remains unknown. This note provides a uniformly minimum variance unbiased estimate of the exact efficiency ratio E(t − μ)2/E( x − μ)2 to help determine the usefulness of t over x in practice.

In this note we furnish a set-up under which the Stein-rule estimator turns out to be a feasible version of the minimum risk estimator.

The risks of estimators incorporating the correction to the sample mean in the spirit of Stein and Lindley are approximated in the case of small disturbances.

In this presentation, we report our studies of some optical and electronic properties of narrow and wide gap materials. The relevance of the present study in relation to solar cells has also been discussed. These studies are essentially based on the earlier work of Penn,(1) Van Vechten,(2) Breckenridgeet al.(3) and Grimes and Cowley.(4) We are then led to a comparative assessment of the various models.(1–4) Although these models give fair estimates of the Penn gap, it is found that none of them are universally applicable. This has been shown to be especially true for some materials including the alkali halides. Possible reasons for these discrepancies are discussed. In the second part of this work, we present our studies of the temperature and pressure dependence of the Penn gap, energy gap and the high frequency dielectric constant. The electronphonon contribution to the total temperature dependence of (i) the energy gap and (ii) the refractive index is then evaluated. The inverse square law governing the variation of deformation potential with the lattice parameter is seen to be valid for a large number of semiconductors.

Using Phillips and Van Vechten's theory the homopolar gap ( E h ), ionic gap ( E c ) and Penn gap ( E p ) have been derived for the layered compound semiconductors SnS 2 and SnSe 2 . The values of E p so derived have been found to be in agreement with the values obtained from the Grimes-Cowley modification of the Penn model, and also with the reflectance spectra of the respective materials. Using the above data the Phillips ionicity has been calculated and the octahedral coordination of SnS 2 and SnSe 2 has been discussed on the basis of the calculated value of ionicity. The bond electronic polarizability has been evaluated using Chemla's approach and the values so obtained have been found in agreement with the values obtained from the Clausius-Mossottirelation. The Varshni formula has been shown to explain fairly well the temperature dependence of energy gap and the constants involved have been derived. The calculated isobaric temperature gradient of E g [( ∂E g ∂T) p ] has been found to be in accordance with the reported values, and the electron lattice interaction has been evaluated.

This paper presents a fairly general and sufficiently weak condition on the observation matrix for the asymptotic normality of the least squares estimator of coefficient vector in a linear regression model. The asymptotic distribution of a statistic for testing the nullity of coefficient vector is also considered.

Two-stage coronary artery ligation in dogs consistently induced ventricular ectopics and raised plasma catecholamine and free fatty acid levels. Ether or pentobarbitone anaesthesia completely abolished the cardiac irregularities and lowered the plasma catecholamine and free fatty acid levels. Chloralose anaesthesia, on the other hand, did not affect the ventricular ectopics, plasma catecholamines and free fatty acids. Haemorrhagic hypotension did not alter the incidence of ventricular ectopics following coronary artery ligation. In chloralose anaesthetized dogs, the neural factors concerned in the genesis of cardiac arrhythmias following coronary artery ligation were analysed by surgical and pharmacological procedures. Bilateral vagotomy, mid-collicular or spinal (C1) transection did not significantly influence the incidence of ventricular ectopics. Spinal (C4-T6) cord destruction completely abolished ventricular ectopics, restored normal rhythm and lowered plasma catecholamine and free fatty acid levels. Spinal anacsthesia with xylocaine was also found to completely abolish ventricular ectopics. Cardiac sympathectomy or bilateral adrenalectomy significantly inhibited the ventricular ectopics and lowered plasma catecholamines and free fatty acids. Ganglionic blockade, adrenergic neurone blockade or β-adrenoceptor blockade restored normal sinus rhythm. The results implicate the prime importance of spinal autonomic loci in the integration of reflex cardiac arrhythmia arising from myocardial ischaemia. The afferent and efferent pathways of the reflex seem to be in the sympathetics.

An experimental investigation into some of the optical and electronic properties of electron beam evaporated thin films of natural galena is presented in this study. In particular, we focus our attention on potentialities of thin films of natural galena for making thin film resistors. The dark (i)I–V characteristics and (ii) sheet resistance and electrical conductivity as a function of temperature, as also (iii) sheet-resistance and I–V characteristics as a function of irradiance constitute the study of the electronic properties while (i) refractive index, (ii) optical density and (iii) transmittance account for the optical properties. The temperature dependent electrical conductivity for these films is shown to obey our studies reported earlier for natural galena crystals. The very large resistivity of these films is accounted for by a very large inter-grain distance as is indicated by the scanning electron micrographs. The energy gap-refractive index values are in complete accord with the Moss relation.

In this paper we develop small-σ and large-T asymptotic expansions of the distribution functions of a family of adaptive shrinkage estimators and theirF-ratios. We demonstrate that the small-σ approximation is much more accurate than the large-T approximation. The small-σ approximate distribution function of the improvedF-ratio is a weighted sum of centralF distribution functions with varying degrees of freedom. This result is useful for forming confidence intervals and testing hypotheses using shrinkage estimators.

The validity of expressions for the exact moments of k-class estimator with 0≦1E;k

This paper presents a brief survey of the developments in the estimation of seemingly unrelated regression equation models covering a period of one and a half decades, including some of the recent results by the authors.

In this article the authors have investigated the situations in which the single-equation least squares estimator is identical with the generalized least squares estimator in the seemingly unrelated regression model. The condition obtained turned out to be advantageous from an empirical point of view as it permits one to decide whether to go for a single-equation least squares method or Zellner's method with estimated disturbance variance covariance matrix for estimating the coefficients in the model.

In our earlier paper [ Srivastava, Agnihotri and Dwivedi (1980) ] the dominance of double k-class over k-class with respect to exact mean squared error matrix criteria is established. It is observed that given a member of k-class, one can pick up a member of double k-class that will provide an improved estimator of the coefficients. This result prompted us to study the exact finite sample properties of the double k-class estimator. For this, we have considered a structural equation containing two endogenous variables and have investigated the properties of double k-class estimators of the coefficients of explanatory endogenous variables assuming characterizing scalars to be non-stochastic.

For the inverse of mean, a class of estimators with finite moments is considered and its properties are analyzed in the context of normal and non-normal populations.

Small-disturbance approximations for the bias vector and mean squared error matrix of the mixed regression estimator for the coefficients in a linear regression model are derived and efficiency with respect to least squares estimator is examined.

This paper considers a class of recently developed biased estimators of regression coefficients and studies its sampling properties when the disturbances are not normally distributed. It has been found that the conditions of dominance of these estimators over the least squares estimator, under non-normality, are quite different than their well-known dominance conditions under normality. Some implications of the results are also discussed.

This paper presents a class of estimators for the mean of a normal population and determines the conditions on characterizing scalars under which the class of estimators uniformly dominates over the conventional sample mean according to the mean-square-error criterion.