Determination of true velocity dispersion and the dark matter problem in clusters of galaxies

According to the convention normally followed the redshifts of the galaxies in a cluster are assumed to be of purely dopplerian origin. The resulting velocity dispersion, when used in the virial theorem, leads to a very large proportion of dark matter to be present in the galaxy clusters. However, the recently proposed model of velocity dependent cosmic drag cause redshifts of photons and it is necessary to develop a procedure to determine the true velocity dispersion from the gross redshift data. A method for this has been presented in the paper. Coma and Perseus clusters have been investigated using this procedure and theM/L ratios for both were found to be approximately of the order of 30, i.e., approximately the order ofM/L ratios for individual galaxies. A study of them -z relation indicates that the galaxies with higher redshifts have fainter magnitudes. Distortion of the redshift plots and the typical elongation of the core regions along the line-of-sight is also explained.     

Point Discharge Current During a Solar Eclipse

The effect of solar eclipse of July 22, 2009, obscuring up to 91 %, upon the value of point discharge current (PDC) has been reported in this paper. The observation had been taken from Kolkata (Lat. 22.56°N, Long. 88.5°E). During the eclipse period, significant variations in the magnitude of PDC were observed than their average value for the same period in other days. The average value of the PDC for the successive ±10 days adjacent to the solar eclipse day was about 2.253 A.U. (Arbitrary Unit), while the minimum value showed about 2.242 A.U. at the time of greatest phase at 06:26.4 IST (Indian Standard Time). The results are mainly interpreted in terms of changes of the conductivity of the medium during the solar eclipse.     

Comparative Analysis of Phytoplankton Composition and Abundance over a Two-Decade Period at the Land–Ocean Boundary of a Tropical Mangrove Ecosystem

Inter-annual variations of phytoplankton abundance and community organization were observed over a two-decade period along with the ancillary parameters at the land–ocean boundary associated with the Sundarban mangrove forest (21°32′ and 22°40′ N and 88°05′ and 89° E), along the NE Coast of the Bay of Bengal. The number of definable Bacillariophyceae species exceeded Dinophyceae taxa, and the total number of bloom-forming species declined from a maximum of ten in 2000 and a minimum of two in 2007. Blooms of the diatom Coscinodiscus radiatus were common in 2000 and 2007. Tide cycles and the onset of the monsoon season played important roles in diurnal and seasonal variability of phytoplankton. Phytoplankton biovolume showed seasonality, with the highest levels during post-monsoon periods and lowest levels during the monsoon period. Phytoplankton abundance was correlated to rainfall patterns, which may be altered by long-term changes in climate.     

Kinematics of large scale asymmetric folds and associated smaller scale brittle — Ductile structures in the proterozoic somnur formation, pranhita — Godavari Valley, South India

The development of structural elements and finite strain data are analysed to constrain kinematics of folds and faults at various scales within a Proterozoic fold-and-thrust belt in Pranhita-Godavari basin, south India. The first order structures in this belt are interpreted as large scale buckle folds above a subsurface decollement emphasizing the importance of detachment folding in thin skinned deformation of a sedimentary prism lying above a gneissic basement. That the folds have developed through fixed-hinge buckling is constrained by the nature of variation of mesoscopic fabric over large folds and finite strain data. Relatively low, irrotational flattening strain (X:Z-3.1-4.8, k<1) are associated with zones of near upright early mesoscopic folds and cleavage, whereas large flattening strain (X:Z-3.9-7.3, k<1) involving noncoaxiality are linked to domains of asymmetric, later inclined folds, faults and intense cleavage on the hanging wall of thrusts on the flanks of large folds. In the latter case, the bulk strain can be factorized to components of pure shear and simple shear with a maximum shearing strain of 3. The present work reiterates the importance of analysis of minor structures in conjunction with strain data to unravel the kinematic history of fold-and-thrust belts developed at shallow crustal level.     

Temperature control,emission abatement and costs: key EMF 27 results from Environment Canada’s Integrated Assessment Model

This paper investigates the potential impacts of alternative international climate change scenarios based on different policies and technological circumstances on future emission pathways and abatement costs. It also examines if these hypothetical scenarios could result in significant emission reductions required to control the global temperature from rising to no more than 2.5 °C above preindustrial level. Using an integrated assessment model, this paper examines these issues under 12 scenarios derived from four policy perspectives and three technology dimensions. Results show that the no-policy-change baseline scenarios lead to high global average temperatures in the future. To control the temperature efficiently, every global region will be required to undertake considerable abatement efforts. Current country pledges alone, even if fully implemented, cannot control the global temperature in the future to within a comfortable zone. There will still be large gap between the reductions needed to meet the 2.5 degree objective, associated with 550 ppm and the reductions associated with existing abatement efforts. Further stringent policies together with favourable technological conditions may lead to the desired level of temperature control. Participation by only a subset of nations not only makes achieving the temperature goal difficult but also costly. To achieve temperature control efficiently, global coordination and full participation by all regions are necessary and global participation may reduce global abatement costs. It is worth noting that abatement costs vary widely across regions under different policy and technology scenarios.     

SARAL/AltiKa Waveform Analysis to Monitor Inland Water Levels: A Case Study of Maithon Reservoir,Jharkhand, India

In the present study, behavior of the SARAL/AltiKa (Satellite with ARgos and ALtiKa) waveforms over Maithon Reservoir (～65 km² of surface area), Jharkhand, India, has been studied. The estimated water level has been compared with the in situ measurements at hydro-gauging station at the dam site. The problem of minimization of errors in the water level retrieval from AltiKa measurements has been resolved by improvement of the retracking method. A real retracking gate detection algorithm based on statistical analysis harnessing various physical parameters of the waveform has been developed, which has been applied to SARAL/AltiKa waveforms over the Maithon reservoir. Comparing the in-situ measurements with altimetry data (from cycle 1, 19 March 2013 to cycle 12, 8 April 2014) showed that it is crucial to improve the retracking method. Results showed accuracy of water level monitoring increased by nearly 76% by the newly developed waveform retracking algorithm over non-retracked water level. We also compared this new method with the existing ice-1 algorithm and found that with the new method there is improvement of ～27% over ice-1 retracked water level. The correlation coefficient values and root mean square values without retracking, with ice-1 algorithm and with newly developed retracking algorithm were 0.87, 0.91, and 0.95, and 8.12 cm, 2.08 cm, and 1.42 cm, respectively. This shows the proposed retracker performed better than ice-1. The retracking procedure helped in outliers' identification and substitution and with waveform fitting and waveform parameter extraction. This algorithm should have good performance capability for retrieving water level over inland water bodies like Maithon reservoir.     

Climate change impact assessment of a river basin using CMIP5 climate models and the VIC hydrological model

Climate change has significant impacts on water availability in larger river basins. The present study evaluates the possible impacts of projected future daily rainfall (2011–2099) on the hydrology of a major river basin in peninsular India, the Godavari River Basin, (GRB), under RCP4.5 and RCP8.5 scenarios. The study highlights a criteria-based approach for selecting the CMIP5 GCMs, based on their fidelity in simulating the Indian Summer Monsoon rainfall. The nonparametric kernel regression based statistical downscaling model is employed to project future daily rainfall and the variable infiltration capacity (VIC) macroscale hydrological model is used for hydrological simulations. The results indicate an increase in future rainfall without significant change in the spatial pattern of hydrological variables in the GRB. The climate-change-induced projected hydrological changes provide a crucial input to define water resource policies in the GRB. This methodology can be adopted for the climate change impacts assessment of larger river basins worldwide.     

Diffusion of the galactic cosmic rays in the vicinity of the solar system

Cosmic-ray propagation in the vicinity of 1 kpc from the Sun is considered. The data on the 10¹²–10¹⁵ eV particle anisotropy, on 10¹² eV electron spectrum, and on temporal cosmic-ray variations are analyzed. The diffusion coefficientD(10¹²–10¹³ eV)=10²⁹–10³⁰ cm²s^–1 inferred from the analysis coincides with its standard value in the large-halo model withh=15 kpc. The total power of cosmic-ray generation, about 3×10⁴⁹ erg per SN in the proton component and about 10⁴⁸ erg per SN in the electron component, typical of the galactic diffusion model is in agreement with the obtained parameters of local sources.     

Petrogenesis of ultramafic rocks and olivine-rich troctolites from the East Taiwan Ophiolite in the Lichi mélange

Mineralogy and Petrology - We examine ultramafic and olivine-rich troctolite blocks of the East Taiwan Ophiolite (ETO) in the Lichi Mélange. Although ultramafic rocks are extensively...