Characterizing small-scale migration behavior of sequestered CO2 in a realistic geological fabric

For typical reservoir conditions, buoyancy and capillary forces grow dominant over viscous forces within a few hundred meters of the injection wells as the pressure gradient due to injection decreases, resulting in qualitatively different plume migration regimes. The migration regime depends on two factors: the capillary pressure of the leading edge of the plume and the range of threshold entry pressures within the rock at the leading edge of the plume. A capillary channel regime arises when these two factors have the same magnitude. Flow patterns within this regime vary from finger-like structures with minimal rock contact to back-filling structures with compact volumes of saturation distributed between fingers. Reservoir heterogeneity is one of the principal factors influencing CO2 migration pathway in the capillary channel regime. Here we characterize buoyancy-driven migration in a natural 2D geologic domain (1 m × 0.5 m peel from an alluvium) in which sedimentologic heterogeneity has been resolved at sub-millimeter (depositional) resolution. The relevant features of the heterogeneity are grain size distribution, which determines the mean and range of threshold pressures and correlation lengths of threshold pressures in horizontal and vertical directions. The relevant physics for this migration regime is invasion percolation, and simulations indicate that CO2 migrates through the peel in a few narrow pathways which cannot be captured by conventional coarse-grid simulations. The storage efficiency of the capillary channel regime would be low and consequently CO2 would also migrate greater distances than expected from models or simulations that neglect the capillary channel flow regime.Bureau of Economic Geolog

Employment, Income and Labour Supply Decision of Rural Households : An Economic Analysis of MGNREGS in Tamil Nadu

In India, Mahatma Gandhi National Rural Employment Guarantee Scheme (MGMGNREGS) is one of the major rural development programmes. It provides guaranteed employment to the rural households for 100 days in a year. This paper has attempted to find out the employment status, income and labour supply decision of the participants and non-participants of MGNREGS in Tamil Nadu. It has also studied the household nutritional security of these households. The study has revealed that the number of migrants in the family, number of livestock units owned, and number of person-days employed in agriculture, nonagriculture and MGNREGS are significantly influenced by the household income of the participants and non-participants of MGNREGS. The analysis of household food-security has shown that the expenditure for all commodities, viz. leisure, cereals, pulses, oils, fruits & vegetables, milk, chicken and fish are positive and significant in the case of MGNREGS participants, whereas the expenditure variable is significant only for two commodities, viz. cereals and oils in case of MGNREGS non-participants. It shows that the MGNREGS participants consume more high-value commodities like milk, chicken and fish, as compared to MGNREGS non-participants. The labour supply decision of sample respondents has shown that the elasticity of labour supply with respect to wage rate is more than one in both participants and non-participants of MGNREGS, indicating that an one per cent increase in wage rate increases labour supply by 1.92 per cent and 2.36 per cent, respectively. In addition, as the number of dependents increases, the household increases labour supply to derive additional income to meet the increased household expenditures. An interesting and encouraging observation is that the scheme has reduced the migration of people from rural to urban areas.MGNREGS, employment, income, labour supply, Agricultural and Food Policy, J21, J22, H23, I31,

Dispersal modes of tree species in the wet forests of southern Western Ghats

Dispersal modes of tree species in a wet evergreen forest at Kakachi in the Kalakad–Mundanthurai Tiger Reserve, southern India are described here. Frugivore visitors to 82 tree species were observed. Biotic agents involved in seed dispersal and seed predation were six species of birds and five species of mammals. Birddispersed species were the most common species (59%), followed by mammal-dispersed species (26%). Primates were less important than bats and civets in seed dispersal. Fifteen per cent of the species had no apparent adaptation for abiotic dispersal (mechanically dispersed) except one wind-dispersed species. Many bird-dispersed species occurred at low density but the total density of bird-dispersed species compares with that of mammal and mechanically dispersed species. Edge or gap habitat species were less abundant than the closed forest ones in all three types of dispersal modes. Species level comparison with other wet forest sites indicates a high degree of similarity between Kakachi and La Selva in central America

Reconciling natural history and species ecology: Myristica beddomei (Myristicaceae) in the Western Ghats, India.

Natural history is an important component of any ecological or conservation research. Very often this is not given adequate attention, and observations on the genera or species are often generalized to other, supposedly similar, congeneric species. In this study, we document the natural history of fruit-frugivore interactions of Myristica beddomei (Myristicaceae) found in the mid-elevation evergreen forests of the Western Ghats, India, and determine how different these interactions are compared to other Myristicaceae species. M.beddomei has a single hard seed covered by an orange-yellow aril. Species of Myristicaceae are usually dispersed by large frugivorous birds, and also by primates in the Neotropics. In South Asia, Myristicaceae dispersal is usually by large birds such as hornbills, but our observations over several years indicate that M. beddomei is not bird-dispersed, even though some fruit traits suggest bird dispersal. Our observations suggest that obligate seed predators like macaques and squirrels can facilitate dispersal of the species. We discuss these observations and explore why such outliers might have evolved in the regio

Conservation amidst political unrest: the case of Manas National Park,India

Across the world there exists a large overlap of biodiversity hotspots with areas experiencing high levels of sociopolitical and ethnic conflicts, making the impacts of such activities a critical factor for long-term conservation of biodiversity in these regions1. India is no exception with many forested areas, including protected areas, experiencing conflicts of varying intensity owing to numerous complicated issues ranging from cultural identity to socio-political and environmental security. Such conflicts not only act as a major impediment to scientific monitoring, protection and management in the biodiversity-rich areas, but also lead to abuse of wildlife and natural areas by conflict parties and opportunistic elements in the absence of adequate protection and monitoring forces. Therefore, in the collective interest of biodiversity conservation, a greater challenge perhaps lies in devising new ways and methods to conserve landscapes in strifetorn areas, where emotions are often charged up and conservation of biodiversity does not figure among the immediate priorities

How the decline in India's harrier population hurts its farmers

Harriers are a group of birds that belong to the hawk family that are active during the day and mostly found in vast open plains and grasslands. There are 16 species of harriers distributed worldwide throughout tropical and temperate regions, and six of these species migrate to India from central Asia and neighbouring areas during the winter. They can travel between 3,500 km and 5,000 km during this migration. Studies on tagged harriers in Africa show that they follow different routes during spring and autumn migrations. We do not really know much about the migration of harriers from India – the routes they fly from, or their breeding grounds – but researchers once found that a tagged harrier from Gujarat migrated to Kazakhstan

Bird, flowers and pollination ecology

The recent paper by Atluri et al.1 provides some interesting information on the pollination ecology of Helectresisora. Information on bird flowers, their visitors and their pollination ecology are few from the sub-continent and this paper is a welcome addition to our knowledge of such systems. However, there are a few major errors in the paper that need to be addressed. The most glaring of these is the identification of the bird pollinator. The authors refer toQuaker babbler (Alcippe poioicephala) as one of the pollinators, but according to Figure 1 d in the article, it appears that the bird is the white-headed babbler (Turdoises affinis). The two are very different birds. T. affinis is bigger with a broader bill that can closely fit an H.isora flower, while A. poioicephala is a small bird and its bill and forehead do not fit the flower as closely as T. affinis. Consequently, pollination efficiency may be different between the two species. Misidentification can have important implications when it comes to conservation and in no case should betaken lightly, especially when the pollinators can be identified by proper use of field guides

Role of mashups, social networking platforms and semantic in revolutionizing web integration: Key insights and enterprise implications

The article examines the emergence and role of mashups in integrating data across the web, how social networking platforms penetrated the web by adding social experiences and how they helped in web integration, while solving some of the issues of mashups. We also discuss how semantic markups evolved in parallel, trying to bring in structured data and why social networking platforms need semantics for building the social graph of users. We take the case of Facebook‟s Open Graph protocol and discuss how semantic markups enhanced web integration by simplifying the process of creating mashups, giving more personalized experiences to the users. Finally, we present an integrated view of the role of mashups, social networking platforms and semantics from the angle of web integration and the insights that enterprises can learn from them

Surgical strategies for recurrent craniofacial meningiomas

Journal ArticleRecurrent cranial base meningiomas are among the most difficult tumors to treat surgically. Although they are histologically benign, these tumors often invade through the cranial base into the infratemporal and pterygopalatine fossae. We reviewed our experience with these tumors to describe the natural history of these lesions as well as provide a possible treatment paradigm