The effect of nested grid sampling on the parameter estimation of a spatial Gompertz diffusion

This paper evaluates the effects of using data observed on regular nested grids on the parameter estimates of a two-parameter Gompertz diffusion model. This new spatial diffusion process represents a technically more complex stage of Gompertz modeling. Firstly, the diffusion model is introduced through an appropriate transformation of a two-parameter Gaussian diffusion process. Probabilistic characteristics of this model, such as the transition densities and the trend functions, are obtained. Secondly, statistical estimation is considered using data obtained on a regular or irregular grid; the explicit expression of the likelihood equations and the parameter estimators are given for regular grids. Finally, a simulation experiment illustrates the results of this paper.     

Delineation of Rajmahal basaltic flows,inter-trappeans and associated coal layers using Audio-magneto-telluric method

The extensive volcanic activity of Rajmahal occurred during early Cretaceous (~117 Ma). Potentially perspective Gondawana sediments containing coal seam is partially covered by these basalts. Basalts as well as coal are already known to be of immense economic importance over Rajmahal traps. The present study mainly deals with delineation of basaltic lava flows and associated coal layers using the Audio-magneto-telluric (AMT) study in the south central region of Rajmahal traps near Suri, West Bengal, India. Initially, the field situations have been simulated using forward model with top alluvium cover followed by basaltic lava flows, a wedge shaped inter-trappean sedimentary formation with second basaltic lava flows and basement at the bottom. The model was constrained using available litholog. The model study reveals the presence of moderately resistive basalts, relatively conductive inter-trappeans and the basement, except the top alluvium layer and thin inter-trappeans. Subsequently, threeAMT sounding have been carried out over Cholaguria, Hatgacha and Pachami, Suri, West Bengal. The field AMT study reveals three basaltic lava flows with varying thickness from ~40m to ~350m and composite thickness of ~620m to ~640m, which match well with the published borehole litholog. The inter-trappeans have been identified at 500m to 620m, 310m to 400m and 500m to 640m depths over Cholaguria, Hatgacha and Pachami, respectively. It is interesting to mention that the identified inter-trappeans are inferred to be coal/shaly-coal which are matching very well with the published borehole lithologs.     

On Data Interpolation at Three Croatian Repeat Stations by Using the Spherical Elementary Currents Systems Method

A general mathematical tool for expanding vector systems on a sphere into basis functions, spherical elementary current system (SECS) method, was applied for separation of the geomagnetic field variations into external and internal parts, over a limited region of central and southeastern Europe. The registered variations at three Croatian repeat stations were compared to the variations estimated by the SECS method using the variations from the different sets of observatories. The results of the SECS method were also compared to a simple assumption that the variations at repeat station are equal to those at particular observatory. The relevance of this comparison was to get an insight about the possibility of using the SECS method for estimating the geomagnetic field variations over Croatia. The guidelines for the application of the SECS method for the purpose of reducing repeat station data were also given.     

Regional variations in electricity demand elasticities: The situation in the Central United States

Within the sizable literature on electricity demand relatively little attention is given to regional variations in electricity demand elasticities. This paper investigates 39 electric utility companies having a total of 93 separate operating regions in order to assess the nature of regional electricity demand elasticity variations. Residential, commercial, and industrial demand functions are estimated for each operating region using a flow adjustment model of demand. The resulting electricity price, measure of economic activity, and natural gas price elasticities vary regionally, but not in a systematic manner. The demand elasticities found in each sector range from highly inelastic to highly elastic with the pattern of elasticity variations exhibiting few spatial trends or relationships. Comparisons between operating region results and more aggregated statewide results indicate that statewide and national analysis of electricity demand masks much regional detail — a result which has important implications for energy policy making.     

Robe's restricted three-body problem with drag

Robe's restricted three-body problem is investigated with regards to the effects of a linear drag force. In particular. the stability of the model's equilibrium points is studied in this respect. Two scenarios are envisaged: the one originally discussed by Robe himself and the one suggested by him and recently analyzed by the present authors, that assumes for the fluid body the structure of a Roche's ellipsoid.     

Geochemical affinities of cobalt and germanium toward metal,silicate, and sulfide phases at high temperature

Hydrothermal studies indicate that Co and Ge are strongly siderophile when metallic iron is in equilibrium with olivine at 900°C and 500 bars. If the metal is replaced by troilite (FeS), Ge is strongly lithophile whereas Co tends to concentrate in the sulfide phase. If iron meteorites were formed in a core derived from the sulfide phase, they would be depleted in Ge but retain Co.     

Foraminiferids from the London Clay at Lower Swanwick and their palaeoecological interpretation

Sixteen foraminiferid assemblages have been studied from the London Clay succession at Lower Swanwick brickyard. These are divided into three faunules which are interpreted as indicating a shallow shelf regime with strong deltaic influences.