Coefficient sets for one dimensional gravity operations using filter theory

Summary Between three at a time of the four quantities ellipticity of the niveau-ellipsoid of the earth, gravity flattening, gravity gradient flattening and ellipticity of the isogravitational surface touching the niveau-ellipsoid at the equator there are functional relations in form of determinant equations.

---

Zusammenfassung Zwischen jeweils drei der vier Grössen Abplattung des Niveauellipsoids der Erde, Schwereabplattung, Schweregradientabplattung und Abplattung der das Niveauellipsoid im Äquator berührenden Fläche konstanter Schwerebeschleunigung werden Funktionalbeziehungen in Form von Determinantengleichungen aufgestellt.

     

Apparent resistivity over a three layer earth with an inhomogeneous interstratum

Summary The theory of resistivity sounding on a three layer earth comprising an inhomogeneous interstratum has been presented. The electrical conductivity in the intermediate layer, embedded between two layers of uniform conductivity, is assumed to follow either generalised power law or exponential variation. A point source of current is placed on the surface. The electric potential functions on the ground surface have been obtained. The expressions for apparent resistivity over the above models for the Wenner and Schlumberger electrode configurations have been derived.     

Cooling age record of domal uplift in the core of the Higher Himalayan Crystallines (HHC), southwest Zanskar, India

The cooling and tectonic history of the Higher Himalayan Crystallines (HHC) in southwest Zanskar (along the Kishtwar-Padam traverse) is constrained by K-Ar biotite and fission-track (FT) apatite and zircon ages. A total of nine biotite samples yields ages in the range of 14–24 Ma, indicating the post-metamorphic cooling of these rocks through ∼ 300°C in the Miocene. Overall, the ages become younger away from the Zanskar Shear Zone (ZSZ), which marks the basement-cover detachment fault between the HHC and the Tethyan sedimentary zone, towards the core of the HHC. The same pattern is also observed for the FT apatite ages, which record the cooling of the rocks through ∼ 120°C. The apatite ages range from 11 Ma in the vicinity of the ZSZ to 4 Ma at the granitic core of the HHC. This pattern of discordant cooling ages across the HHC in southwest Zanskar reveals an inversion of isotherms due to fast uplift-denudation (hence cooling) of the HHC core, which is, in turn, related to domal uplift within the HHC. The Chisoti granite gneiss is the exposed domal structure along the studied traverse. Cooling history of two granite gneisses at the core of the HHC is also quantified with the help of the biotite, zircon and apatite ages; the time-temperatures thus obtained indicate a rapid pulse of cooling at ∼ 6 Ma, related to accelerated uplift-denudation of the HHC core at this time. Long-term denudation rates of 0.5–0.7 mm/yr are estimated for the high-grade rocks of the Higher Himalaya in southwest Zanskar over the past 4.0–5.5 m.yr.     

Cosmogenic and nucleogenic isotopic changes in Mars: their rates and implications to the evolutionary history of Martian surface

We present calculations of rates of production of several nuclides in the Martian atmosphere and in the regolith due to nuclear interactions of cosmic ray and radiogenic particles and consider their implications to the evolutionary history of Mars. Nuclides selected are those which, considering their chemical properties, may be useful as tracers for delineating the past histories of the Martian atmosphere and regolith. Calculations are presented for different assumed atmospheric pressures. The regolith production rates for the present thin Martian atmosphere (approximately 20 g cm-2) are expected to be fairly robust because they are based primarily on observed cosmogenic effects in the Moon, for which semiempirical estimates of nuclide production rates have been provided earlier by Reedy (1981). Uncertainties which arise in the calculations of nuclide production rates for an earlier hypothetical Martian atmosphere of approximately 300-500 g cm-2 thickness are discussed. Compared to cosmic ray production rates, the nucleogenic production rates are smaller by several orders of magnitude. However, the nucleogenic production extends to much deeper levels, whereas the cosmogenic production is essentially confined to the top 750-1000 g cm-2 depth. Important examples of nucleogenic production are discussed. Isotopes of neon and argon appear to be very promising for delineating relative magnitudes of a number of planetary processes related to the temporal changes in the thickness of the atmosphere, as well as their release from the regolith. However, quantification of the processes would require higher-precision isotopic data for the atmosphere and also direct measurements of isotopic ratios in the Martian regolith, along with supplementary information on changes in the isotopic compositions of hydrogen, carbon, and nitrogen, which are affected by a variety of mechanisms of escape of gases from the atmosphere. Cosmogenic effects are minimal in these cases. We show that although we can at present draw but limited inferences, the planet Mars presents a unique opportunity to use cosmogenic nuclides as tools to delineate the evolutionary history of the planet as a whole, as well as its regolith and the atmosphere. This arises because of two factors: minimal degassing of the planet, and a fairly intense chemical weathering history of the upper surface. Consequently, an appreciable fraction of some of the isotopes of volatile elements is contributed by nuclear reactions.     

Effect of Nickel and Cadmium on Ammonium Uptake Kinetics of Free and Immobilized Cells of Anacystis nidulans

The stress effect of Ni and Cd on the ammonium uptake varied significantly (ANOVA test) in free and immobilized state of the test organism. The effect due to the interaction between different variables (cell state type, metal type and metal dose) was studied to depict the significant or non‐significant variation in the ammonium uptake by free and immobilized cells in the presence of metal ions. Ammonium uptake exhibited a competitive mode of inhibition in the presence of Ni in both free and immobilized state of the organism. However, Cd exhibited non‐competitive and competitive inhibition in free and immobilized cells, respectively. The study demonstrates that there is a considerable influence of metal ions on the ammonium uptake. Cd was found to be more toxic compared to Ni in both free and immobilized state.     

Whistler observations of magnetospheric electric field in the night side plasma-sphere at low latitude

Whistlers recorded at low latitude ground stations of Gulmarg, Nainital and Varanasi were used to infer the east-west component of electric field on the nightside plasmasphere atL=1.2, 1.12, and 1.07 during magnetic storm periods. The method of measuring electric field from the observed cross-L motions of whistler ducts within the plasma-sphere, indicated by changes in nose frequency of whistlers has been outlined. The nose frequencies of the non-nose whistlers under consideration have been deduced from Dowden-Allocock linear Q-technique. The results show eastward electric fields of 0.7 mVm^–1 in the equatorial plane of Gulmarg and 0.3 mVm^–1 in the equatorial plane of Nainital in the premidnight local time sector. Near midnight, there is a sharp transition from eastward field to a westward electric field of 0.2–0.7 mV m^–1 for Gulmarg, 0.3–0.5 mV m^–1 for Nainital and 0.1–0.3 mVm^–1 for Varanasi.     

Equilibrium structure of stars obeying a generalized differential rotation law

In the present paper we have considered the problem of determining the equilibrium structure of differentially rotating stars in which the angular velocity of rotation varies both along the axis of rotation and in directions perpendicular to it. For this purpose, a generalized law of differential rotation of the type ² =b ₀+b ₁ s ²+b ₂ s ⁴+b ₃ z ²+b ₄ z ⁴+b ₅ z ² s ² (here is a nondimensional measure of the angular velocity of a fluid element distants from the axis of rotation andz from the plane through the centre of the star perpendicular to the axis of rotation, andb's are suitably chosen parameters) has been used. Whereas Kippenhahn and Thomas averaging approach has been used to incorporate the rotational effects in the stellar structure equations, Kopal's results on Roche equipotentials have been used to obtain the explicit form of the stellar structure equations, which incorporate the rotational effects up to second order of smallness in the distortion parameters. The method has been used to compute the equilibrium structure of certain differentially rotating polytropes. Certain differentially rotating polytropes. Certain differentially rotating models of the Sun have also been computed by using this approach.     

The 2020 Mw 5.5 Mizoram earthquake and associated swarm activity in the junction of the Surma Basin and Indo-Myanmar Subduction Region

Natural Hazards - Two Artificial Intelligence (AI) methods, Fuzzy Inference System (FIS) and Artificial Neural Network (ANN), are applied to Landslide Susceptibility Mapping (LSM), to compare...     

Integration of satellite remote sensing and geophysical techniques (electrical resistivity tomography and ground penetrating radar) for landslide characterization at Kunjethi (Kalimath), Garhwal Himalaya,India

Natural Hazards - During the extreme precipitation event of 15th–17th June 2013 in Garhwal Himalaya, glacial lake outburst flooding accompanied by numerous landslides and flash flood events...