Composition of macrobenthos from the Central Indian Ocean Basin

The deep sea is well known for its high faunal diversity. But the current interest in its abundant polymetallic nodules, poses a threat to the little known benthic organisms surviving in this unique environment. The present study is the first attempt to document the Indian Ocean abyssal benthic diversity of macroinvertebrates and to investigate its relation to the surface primary production (chl-a), sediment labile organic matter, organic carbon and texture. The present study is based on 87 individuals. Altogether 39 macroinvertebrate genera were obtained from water depths of 4500–5500 m from 23 box cores. Reduction in macrobenthic density was seen towards the southern latitudes. The area was dominated by deposit feeding macrobenthos. Vertically, the fauna was distributed down to 30 cm depth, with the highest faunal density in the top 2–5 cm sediment section. The values for population density were strongly correlated with surface water chl-a and sediment protein, indicating supply of fresh organic matter as a critical factor for maintaining the deep sea benthic diversity and abundance.     

The CLIVAR C20C project: skill of simulating Indian monsoon rainfall on interannual to decadal timescales. Does GHG forcing play a role?

The ability of atmospheric general circulation models (AGCMs), that are forced with observed sea surface temperatures (SSTs), to simulate the Indian monsoon rainfall (IMR) variability on interannual to decadal timescales is analyzed in a multimodel intercomparison. The multimodel ensemble has been performed within the CLIVAR International “Climate of the 20th Century” (C20C) Project. This paper is part of a C20C intercomparison of key climate time series. Whereas on the interannual timescale there is modest skill in reproducing the observed IMR variability, on decadal timescale the skill is much larger. It is shown that the decadal IMR variability is largely forced, most likely by tropical sea surface temperatures (SSTs), but as well by extratropical and especially Atlantic Multidecadal Oscillation (AMO) related SSTs. In particular there has been a decrease from the late 1950s to the 1990s that corresponds to a general warming of tropical SSTs. Using a selection of control integrations from the World Climate Research Programme’s (WCRP’s) Coupled Model Intercomparison Project phase 3 (CMIP3), it is shown that the increase of greenhouse gases (GHG) in the twentieth century has not significantly contributed to the observed decadal IMR variability.     

Fractal analysis of major faults in India on a regional scale

The seismicity of a region is implicit of the causal faulting mechanisms and geodynamic diversity of the subsurface regime nucleating earthquakes of different magnitudes, several of which may be as devastating as ones historically reported in global perspective of tectonic complexity as in the case of India. Fractal analysis using box-counting method for the major fault networks across the country estimates fractal dimension, D_f, values to be varying between 0.88 and 1.36. The fault segments in parts of northwest Himalayas, northeast India and Indo-Gangetic plains, are observed to be associated with higher D_f values implicating high seismicity rates. On the other hand, low D_f values in the peninsular India indicate isolated pattern of the underlying faults. The fractal dimension is observed to be indicative of predominant faulting types — higher values conforming to thrust faulting mechanism while lower to strike slip tectonism.     

Planning for Delhi

This paper reviews the planning and city building processes in Delhi in three periods — the imperial Mughal, the imperial British and the post-Independence. In the two earlier periods, the plans followed the ideals and tastes of the ruling elites and the cities were built to meet their needs. But the cities were well adapted to the technologies of the times and patterns of social interactions among the residents. Consequently, they provided to most of their residents a living environment which was efficient, healthy and satisfying. One reason for this was that Delhi was a relatively small city and increase in population was slow.The half century since 1941 has witnessed an unprecedented increase in population which has gone up from less than 700,000 in 1941 to 8.4 million in 1991. The increase has been due partly in response to expansion of employment in public administration, trade, finance and manufacturing industries, and partly to large in-migration of displaced persons from Pakistan during 1947–48, and from other states of India throughout the period.The efforts of the public agencies — the Central Government and the Delhi Development Authority — to expand housing have been matched by those of individuals and cooperative societies. But the efforts have been focussed on providing housing to people of medium and high income groups; the housing needs of the poor have been met by rapid growth of slums and unauthorised colonies. Expansion of physical and social infrastructure has also proved inadequate to meet the demands on it. The reliance in the absence of a mass transit facility, on a miscellany of motor vehicles for movement within the city, has resulted in very high levels of air and noise pollution.The hopeful beginning with long-term planning, made with successful implementation of the first master plan 1961–81, has suffered a set back as a result of the failure of the Central Government to approve the second master plan 1981–2001. The Regional Plan 2001 for the National Capital Region, approved in 1988 by all the governments concerned, is also not being implemented. In the resulting, impasse there is unplanned growth of a giant conurbation adding to its various problems. The paper recommends revival of metropolitan and regional planning for direction of growth of the conurbation to 2010.     

A continuum method of pile driving analysis: Comparison with the wave equation method

What may be called a ‘Continuum’ method of finite element analysis is used in this paper to predict the behaviour of a pile during driving. In this both the pile and the soil are treated as two distinct parts of the same solid continuum, but with different properties. The behaviour of the soil medium, assumed to be semi-infinite and nonlinear, is represented by the hyperbolic stress-strain relationship. Discretizing the pile-soil system in turn by conventional axi-symmetric and mapped finite elements, the problem is solved in the time-domain using the central difference scheme.

The example considered is that of a fully embedded steel pipe pile for which both field test data and Wave Equation solution are available. Results show that: the Continuum Method is capable of a greater degree of accuracy than the conventional Wave Equation Method, but it is far more expensive than the latter in terms of computational effort needed; the effects of radiation damping and wave dispersion in the soil are found to be small; and the mapped finite elements give significantly better results than conventional elements.     

Leadership and Trade-Offs Between Social–Ecological Outcomes in Community-Governed Forests

I explore the effect of leadership on the trade-off between social and ecological outcomes of community driven efforts in governing forests globally. I do so by using logistic regression and QCA (qualitative comparative analysis) for the analysis of cross-sectional data from the International Forestry Resources and Institutions (IFRI) research program. While the net effect of leadership on the trade-off in forestry outcomes is significant, there are multiple causal paths via which various factors influence the trade-off in forestry outcomes. Some of these paths take place in the presence of leadership, while the presence or the absence of leadership is irrelevant for the rest of the paths. This finding indicates that leaders often play an important role in the decisionmaking process during the governance of forests, especially when hard decisions need to be taken.     

Groundwater arsenic contamination in Ganga–Meghna–Brahmaputra plain, its health effects and an approach for mitigation

The authors’ survey of the Ganga–Meghna–Brahmaputra (GMB) plain (area 569,749 km²; population >500 million) over the past 20 years and analysis of more than 220,000 hand tube-well water samples revealed groundwater arsenic contamination in the floodplains of the Ganga–Brahmaputra river (Uttar Pradesh, Bihar, Jharkhand, West Bengal, and Assam) in India and the Padma–Meghna–Brahmaputra river in Bangladesh. On average, 50 % of the water samples contain arsenic above the World Health Organization guideline value of 10 μg/L in India and Bangladesh. More than 100 million people in the GMB plain are potentially at risk. The authors’ medical team screened around 155,000 people from the affected villages and registered 16,000 patients with different types of arsenical skin lesions. Arsenic neuropathy and adverse pregnancy outcomes have been recorded. Infants and children drinking arsenic-contaminated water are believed to be at high risk. About 45,000 biological samples analyzed from arsenic-affected villages of the GMB plain revealed an elevated level of arsenic present in patients as well as non-patients, indicating that many are sub-clinically affected. In West Bengal and Bangladesh, there are huge surface water in rivers, wetlands, and flooded river basins. In the arsenic-affected GMB plain, the crisis is not over water scarcity but about managing the available water resources.     

Self-similar MHD shock waves for a rotating atmosphere under the force of gravitation

A study has been made of self-similar magnetohydrodynamic spherical shock waves for a rotating atmosphere taking into account the effect of self-gravitation. The energy is assumed to vary with some power of time. A study has been made to investigate the effects of magnetic field in the presence and absence of gravitation. The variation of flow variables is shown in tables for several different cases of physical interest.     

Heating of the intracluster medium by quasar outflows

We study the possibility of quasar outflows in clusters and groups of galaxies heating the intracluster gas in order to explain the recent observation of excess entropy in this gas. We show that radio galaxies alone cannot provide the energy required to explain the observations but the inclusion of Broad Absorption Line (BAL) outflows can do so, and that in this scenario most of the heating takes place atz ∼ 1–4, the “preheating” epoch being at a lower redshift for lower mass clusters.