Showing papers in "Current Science in 2004"

Physiology and molecular biology of salinity stress tolerance in plants

Abstract: ions and to some extent Cl and SO 4 2 of Mg 2+ and nutrient imbalance caused by excess of Na + and Cl ions. Salinity stress response is multigenic, as a number of processes i n- volved in the tolerance mechanism are affected, such as var ious compatible solutes/osmolytes, polyamines, reactive oxygen species and antioxidant defence mecha- nism, ion transport and compartmentalization of inj u- rious ions. Various genes/cDNAs encoding proteins involved in the above-mentioned processes have been identified and isolated. The role of genes/cDNAs e n- coding proteins involved in regulating other genes/ pro- teins, signal transduction process involving hormones like ABA, JA and polyamines, and strategies to i mprove salinity stress tolerance have also been di scussed. EXCESS amount of salt in the soil adversely affects plant growth and development. Nearly 20% of the world's cul- tivated area and nearly half of the world's i rrigated lands are affected by salinity 1

Turmeric and curcumin: Biological actions and medicinal applications

Abstract: Turmeric (Curcuma longa) is extensively used as a spice, food preservative and colouring material in India, China and South East Asia. It has been used in traditional medicine as a household remedy for various diseases, including biliary disorders, anorexia, cough, diabetic wounds, hepatic disorders, rheumatism and sinusitis. For the last few decades, extensive work has been done to establish the biological activities and pharmacological actions of turmeric and its extracts. Curcumin (diferuloylmethane), the main yellow bioactive component of turmeric has been shown to have a wide spectrum of biological actions. These include its antiinflammatory, antioxidant, anticarcinogenic, antimutagenic, anticoagulant, antifertility, antidiabetic, antibacterial, antifungal, antiprotozoal, antiviral, antifibrotic, antivenom, antiulcer, hypotensive and hypocholesteremic activities. Its anticancer effect is mainly mediated through induction of apoptosis. Its antiinflammatory, anticancer and antioxidant roles may be clinically exploited to control rheumatism, carcinogenesis and oxidative stress-related pathogenesis. Clinically, curcumin has already been used to reduce post-operative inflammation. Safety evaluation studies indicate that both turmeric and curcumin are well tolerated at a very high dose without any toxic effects. Thus, both turmeric and curcumin have the potential for the development of modern medicine for the treatment of various diseases.

Ayurveda and natural products drug discovery

Abstract: This review attempts to portray the discovery and development of medicine from galenical to genomical, with a focus on the potential and role of ayurveda. Natural products, including plants, animals and minerals have beenthe basis of treatment of human diseases. Indigenous people derived therapeutic materials from thousands of plants; however discovering medicines or poisons remains a vital question. Ayurveda is a traditional Indian medicinal system being practised for thousands of years. Considerable research on pharmacognosy, chemistry, pharmacology and clinical therapeutics has been carried out on ayurvedic medicinal plants. Many of the major pharmaceutical corporations have renewed their strategies in favour of natural products drug discovery and it is important to follow systems biology applications to facilitate the process. Numerous drugs have entered the international pharmacopoeia through the study of ethnopharmacology and traditional medicine. For ayurveda and other traditional medicines newer guidelines of standardization, manufacture and quality control are required. Employing a unique holistic approach, ayurvedic medicines are usually customized to an individual constitution. Traditional knowledge-driven drug development can follow a reverse pharmacology path and reduce time and cost of development. New approaches to improve and accelerate the joint drug discovery and development process are expected to take place mainly from innovation in drug target elucidation and lead structure discovery. Powerful new technologies such as automated separation techniques, high-throughput screening and combinatorial chemistry are revolutionizing drug discovery. Traditional knowledge will serve as a powerful search engine and most importantly, will greatly facilitate intentional, focused and safe natural products research to rediscover the drug discovery process.

Prospects of arbuscular mycorrhizal fungi in phytoremediation of heavy metal contaminated soils

Abstract: Arbuscular mycorrhizal (AM) associations are integral, functioning parts of plant roots and are widely recognized as enhancing plant growth on severely disturbed sites, including those contaminated with heavy metals. Theyare reported to be present on the roots of plants growing on heavy metal contaminated soils and play an important role in metal tolerance and accumulation. Isolation of the indigenous and presumably stress-adapted AM fungi can be a potential biotechnological tool for inoculation of plants for successful restoration of degraded ecosystems. This review highlights the potential of AM fungi for enhancing phytoremediation of heavy metal contaminated soils.

Chemistry and biology of bile acids

Abstract: This review makes an attempt to combine the insights gained into the biochemistry and physiology of bile acids with the elegant supramolecular systems designed from them. Bile acids are cholesterol-derived facial amphiphiles responsible for the solubilization of cholesterol and fat through mixed micelle formation with phospholipids. An intriguing aspect of bile acids is that their chemical structure has been postulated to correlate with vertebrate evolution. However, the etiology of molecular evolution of bile acids is still poorly understood. There has been a steady progress in the studies aimed at elucidating physiological functions and developing pharmacological applications of bile acids. In recent years, bile acids and their analogues have been extensively utilized as supramolecular receptors for various types of guest molecules and ions. Under certain defined conditions, the supramolecular association of bile acids and their derivatives leads to gel formation. Thus, modified bile acids might find use in the design of futuristic materials.

Residue burning in rice-wheat cropping system: causes and implications

Abstract: Combine harvesting technologies, which have become common in RWS (rice-wheat system) in India, leave behind large quantities of straw in the field for open burning of residue. Such burnings result in perturbations to the regional atmospheric chemistry due to emissions of trace species like CO 2 , CO, CH 4 , N 2 O, NO x , NMHCs and aerosols. The emissions of CH 4 , CO, N 2 O and NO x have been estimated to be about 110, 2306, 2 and 84 Gg respectively, from rice and wheat straw burning in India in the year 2000. Residue burning causes nutrient and resource loss and adversely affects soil properties, thus calling for improvement in harvesting technologies and sustainable management of RWS.

Molecular markers in herbal drug technology

Abstract: Herbal drug technology is used for converting botanical materials into medicines, where standardization and quality control with proper integration of modern scientific techniques and traditional knowledge is important. The use of chromatographic techniques and marker compounds to standardize botanical preparations has limitations because of their variable sources and chemical complexity. DNA-based molecular markers have utility in the fields like taxonomy, physiology, embryology, genetics, etc. DNA-based techniques have been widely used for authentication of plant species of medicinal importance. Pharmacognosy mainly addresses quality-related issues using routine botanical and organoleptic parameters of crude drugs, and chemoprofiling-assisted characterization with chromatographic and spectroscopic techniques. The new pharmacognosy includes all the aspects of drug development and discovery, where biotechnology-driven applications play an important role. Current focus on chemotype-driven fingerprinting and related techniques requires integration with genotype-driven molecular techniques so that an optimal characterization of botanical materials is possible. This review provides a brief account of various DNA-based technologies that are useful in genotyping and quick identification of botanicals with suitable examples.

Biological fuel cells and their applications

Abstract: One type of genuine fuel cell that does hold promise in the long-term is the biological fuel cell. Unlike conventional fuel cells, which employ hydrogen, ethanol and methanol as fuel, biological fuel cells use organic products produced by metabolic processes or use organic electron donors utilized in the growth processes as fuels for current generation. A distinctive feature of biological fuel cells is that the electrode reactions are controlled by biocatalysts, i.e. the biological redox-reactions are enzymatically driven, while in chemical fuel cells catalysts such as platinum determine the electrode kinetics. This article provides a brief introduction to biological fuel cells.along with their envisaged applications.

Characterization and screening of bacteria from rhizosphere of rice grown in acidic soils of Assam

Abstract: Three groups of rhizobacteria were isolated using three selective culture media from the rhizosphere of rice grown at fifteen locations in Assam. Four bacteria in each group were selected for taxonomic identification, characterization and also for screening the superior isolates to promote rice growth. The isolates of phosphate-solubilizing and fluorescent bacterial groups were found to be eight different species. The three isolates of azospirilla group were identified as Azospirillum brasilense and the fourth isolate was identified as Azospirillum amazonense. RAPD analysis of the Azospirillum isolates indicated that azospirilla were four distinct genotypes. These bacterial strains showed differences in growth pattern, IAA production level (2.0-21.6 μg/ml of culture supernatant), antibiotic resistance profile and nitrogenase activity (0.33-0.75 nmol C 2 H 4 h - 1 100 - c c root volume) in the inoculated roots. A. amazonense A10 (MTCC 4716), Bacillus pantothenticus P4 (MTCC 4695) and Pseudomonas pieketti Psd6 (MTCC 4715) increased rice grain yield by 55.5, 12.2 and 76.9% over the uninoculated control in micro-plot experiments and were found to be at par with or superior to the exotic strains of A. brasilense CDJA and Pseudomonas fluorescence MTCC 103.

Water for India in 2050: first-order assessment of available options

Abstract: Water resources of India are examined in the context of the growing population and the national ambition to become and be seen as a developed nation. The motivation was provided by the continuing debate on the proposed project for interlinking of rivers by National Water Development Agency. The population of India is expected to stab ilize around 1640 million by the year 2050. As a result, g ross per capita water availability will decline from ~ 1820 m 3 / yr in 2001 to as low as ~ 1140 m 3 /yr in 2050. Total water requirement of the country for various activities around the year 2050 has been assessed to 1450 km 3 /yr. This is significantly more than the current estimate of ut ilizable water resource potential (1122 km 3 /yr) through conventional development strategies. Therefore, when compared with the availability of ~ 500 km 3 /yr at present, the water availability around 2050 needs to be almost trebled. Various options have been considered in quant itative terms, as possible sources to augment the anticipated deficit. It is argued that due to consideration s of gest ation period and capital requirements, rainwater harvesting and water-conservation measures must receive the highest priority followed by renovation and recycling to be followed by intra- and then inter-basin transfers in the last phase. But, investigations and planning pro cesses for all options must begin immediately. WITH rapid population growth and rising expectation for a better life, the natural resources of our earth face i ncreasing pressure. It is p aramount that basic resources for human survival, viz. air, land and water must be properly managed. The quantity and quality of these r esources are critical to ensure adequate food supplies, pu blic health and transportation. In particular, the manage ment of water resources has profound impact on society with regard to quality of life. Water-management decisions can have environmental, physical, social and economic impacts that are wid espread and pervasive. It is, therefore, necessary to have most relevant information for arriving at rational dec isions that will result in the maximum amount of benefit to most people. Accurate and reliable information on the w ater resource system can, therefore, be a vital aid to strategic management of the resource. To appreciate this, an ove rview of the emerging water-resource scenario in I ndia is presented in the following.

Origin of agriculture and domestication of plants and animals linked to early Holocene climate amelioration

Abstract: Domestication of plants and animals was necessary for the evolution of agriculture, spatial expansion and population increase of humans during the Holocene, which facilitated the evolution of technically innov ative societies. The agricultural practices enabled pe ople to establish permanent settlements and expand urbanbased societies. Domestication of plants and animals transformed the profession of the early humans from hunting and gathering to selective hunting, herding and settled agriculture. The earliest archaeological evidences, found throughout the tropical and subtropical areas of southwestern and southern Asia, northern and central Africa and Central America, suggest rapid and large-scale domestication of plants and animals ca. 10,000–7000 cal years BP. This interval corresponds to an intense humid phase and equable climates, as observed in numerous paleo records across the regions. I suggest that domestication of plants and animals and subsequent beginning of agr iculture were linked to cli mate amelioration in the early Holocene. CLIMATE has played a critical role in the evolution of fauna and flora. Proxy data suggest occurrence of wid espread repeated, abrupt climate changes throughout the geological record 1 . Persistent abrupt changes in climate may alter ecological landscape, le ading to faunal adaptation. Human adaptation and migration in response to s evere climate changes are known from the paleo records 2 . R ecent archaeological findings from Yana River, Siberia, ind icate that humans adapted to the harsh, frigid climate of the Arctic during the late Pleistocene about 27,000 year ago 3

Degradation of β-lactam antibiotics

Abstract: Recent developments in the chemistry and biology of β-lactam antibiotics which culminated with the introduction of several clinically useful classical and non-classical β-lactams have been most thrilling and highly rewarding. While this review touches upon the historical development of β-lactams and their reactivity in a nutshell, it provides an overview of various aspects of chemical and enzymatic degradation of β-lactams, pointing to various routes of degradation, degradation products and allergenicity.

Antioxidants: New-generation therapeutic base for treatment of polygenic disorders

Abstract: Hyperphysiological burden of free radicals causes imbalance in homeostatic phenomena between oxidants and antioxidants in the body. This imbalance leads to oxidative stress that is being suggested as the root cause of aging and various human diseases like atherosclerosis, stroke, diabetes, cancer and neuro degenerative diseases such as Al zheimer’s disease and Parkinsonism. Therefore, in modern Western medicine, the balance between antioxidation and oxidation is believed to be a critical concept for maintaining a healthy biological system. Researches in the recent past have accumulated enormous evidence advocating enrichment of body systems with antioxidants to co rrect vitiated homeostasis and prevent the onset as well as treat the disease caused/fostered due to free rad icals and related oxidative stress. This article pr esents current understanding of the role of free radicals and oxidative stress in pathogen esis of various diseases and advancements made in developing antioxidantbased therapeutics and also discuss the opportunities to develop therapeutics from traditional medicinal practice.

Integrating marker-assisted selection in crop breeding: Prospects and challenges

Abstract: Mapping and tagging of agriculturally important genes have been greatly facilitated by an array of molecular markers in crop plants Marker-assisted selection (MAS) is gaining considerable importance as it would improve the efficiency of plant breeding through precise transfer of genomic regions of interest (foreground selection) and accelerating the recovery of the recurrent parent genome (background selection) MAS has been more widely employed for simply inherited traits than for polygenic traits, although there are a few success stories in improving quantitative traits through MAS The success of MAS depends upon several critical factors, including the number of target genes to be transferred, the distance between the flanking markers and the target gene, the number of genotypes selected in each breeding generation, the nature of germplasm and the technical options available at the marker level With the advent of third-generation marker technologies, such as the single nucleotide polymorphisms, the power and efficiency of genotyping are expected to improve in the coming decades The present review discusses the basic requirements and the potential applications of MAS in crop plants, the design parameters in a MAS scheme, recent developments in MAS strategies and genotyping techniques, and the significance of integrating MAS into conventional plant breeding programmes

Microzonation of earthquake hazard in Greater Delhi area

Abstract: A spate of earthquakes in the recent past, causing extensive damage,has heightened the sensitivity of engineers and planners to the looming seismic risk in densely populated Indian cities. Delhi city is in a seismically active region and hence it is important to understand the existing earthquake hazard to the city on a scientific basis. This article, after discussing the seismo-tectonic status of the city and its environs, presents probabilistic seismic hazard analysis of an area of 30 km x 40 km with its centre at India Gate, Delhi city. The quantified hazard in terms of the rock level peak ground acceleration value is mapped on a grid size of 1 km x 1 km, for a return period of 2500 years. In engineering parlance, this corresponds to a probability of exceedance of 2% in a design life of 50 years. This map can be used as the basis for further site-specific studies at soft, soil deposits.

Viral infections and trace elements : A complex interaction

Abstract: Several trace elements are essential micronutrients and are required for various body functions and well being of the immune system The deficiencies of trace elements and infectious diseases often coexist and exhibit complex interactions Several trace elements such as selenium, zinc, copper, manganese, etc have immunomodulatory functions and thus influence the susceptibility to the course and the outcome of a variety of viral infections Some trace elements inhibit virus replication in the host cells, thus showing antiviral activity Many trace elements act as antioxidants or help such functions that not only regulate immune responses of the host, but also may alter the genome of the viruses The grave consequences of this may be the emergence of new infections The trace elements, viruses and immune system interactions have been briefly reviewed in this article to highlight the importance of trace element nutrition of host in not only optimizing immune response to infections, but also in preventing viral mutations which could increase viral pathogenicity

Phytochemical variability in commer- cial herbal products and preparations of Withania somnifera (Ashwagandha)

Abstract: Withania somnifera (Hindi - Ashwagandha, English - winter cherry) is used in Ayurvedic formulations for a variety of health-promoting effects. Several mono- and poly-herbal products commercially available in the Indian market were quantitatively analysed for a number of chemical constituents. The results revealed wide variations in the content of all seven constituents tested. More than 70-fold variation in the daily intake of withaferin A (the main active constituent of Ashwagandha) was found in the products. The study thus emphasizes the need for stringent phytochemical standardization of herbal products.

Biotechnological potential of marine sponges

Abstract: Marine sponges (Porifera) have attracted significant attention from various scientific disciplines. Remarkable traces, left by sponges in the fossil records have been studied by paleontologists and evolutionary biologists. As sponges produce various novel chemical molecules, they have been a goldmine to chemists and also found their way into biotechnological applications. Microbiologists became fascinated by these unique animals with the discovery that sponges contain an abundance of unusual microorganisms, having potential for drug discovery. Cell biologists are investigating these simple animals to understand their basic organization on the cellular and skeletal level. Since the last few years, molecular biologists are working on sponge genome, which will contribute to the understanding of the evolution of molecular mechanism of metazoan genes and diseases. This review aims to provide an overview of the different interdisciplinary approaches involved in the exploration of marine sponges for their biotechnological potential.

IMD's new operational models for long-range forecast of southwest monsoon rainfall over India and their verification for 2003

Abstract: In 2003, India Meteorological Department (IMD) introduced several new models for the long-range forecast of the southwest monsoon rainfall. With this, it has become possible to issue the long-range forecasts in two stages. On 16 April, IMD issued the forecast for the 2003 southwest monsoon rainfall for the country as a whole, giving its users an extra lead time of about 40 days. On 9 July, IMD issued a forecast update and additional forecasts for three broad homogeneous regions of India. It also gave a five-category probabilistic forecast. In view of its importance for agriculture, for the first time, IMD also issued a forecast for July rainfall. The development of the new models is discussed in this article. The forecasts issued operationally in 2003 using these new models have proved to be accurate.

Toxicity analysis of 33'44'5-pentachloro biphenyl through chemical reactivity and selectivity profiles

Abstract: Global reactivity profiles like electronegativity, hardness, polarizabilty, electrophilicity index and local selectivity profiles like condensed Fukui function and regional electrophilic power of 33'44'5-pentachloro biphenyl have been calculated using B3LYP/6-31G* including both Hartree-Fock and density functional theory-based exchange functionals in both gas and solution phases in order to gain insights into the toxic nature of this compound. Both global and local electrophilicity have been found to be adequate in explaining respectively the overall toxicity of the selected system and the most probable sites of toxicity, viz. Cl 2 0 , C 1 0 and H 1 4 . Planarity and electron affinity are the possible criteria for determining the toxic nature of this biphenyl.

Biomass gasification technology - a route to meet energy needs

Abstract: The paper addresses a distributed power generation system that has evolved at the Indian Institute of Science, Bangalore. The technological and field-related experience pertaining to open top re-burn down draft biomass gasification system coupled with the internal combustion engine or thermal device are brought out. The gasifier reactor design uses dual air entry – air nozzles and open top to help in establishing a thick high temperature zone to remove the contaminants in the product gas; a gas clean-up system to further refine the gas to ultra-pure quality. These elements are integrated with other sub-systems, namely feedstock preparation, ash handling, water treatment, process automation and other accessories to form an Independent Power Producer.Based on this technology there are over 30 units operating in India and abroad, with an accumulated capacity of over 20 MW. Over 80,000 h of operation of these systems have resulted in a saving of about 350 tons of fossil fuel, implying a saving of about 1120 tons of $CO_{2}$ – a promising candidate for Clean Development Mechanisms (CDMs),other than reduction in toxic gases like $NO_{x} and SO_{x}$.

Water quality in sustainable water management

Abstract: Water pollution is a serious problem as almost 70% of India’s surface water resources and a growing number of its groundwater reserves have been contaminated by biological, organic and inorganic pollutants. Pollution of surface and groundwater resources occurs through point and diffuse sources. Examples of point source pollution are effluents from industries and fromsewage-treatment plants. Typical examples of diffuse pollution sources are agricultural runoffs due to inorganic fertilizers and pesticides and natural contamination of groundwater by fluoride, arsenic and dissolved salts due to geo-chemical activities. In pursuit of measures to achieve sustainability in water management, the Centre for Sustainable Technologies (CST) at the Indian Institute of Science (IISc) has begun to address treatment of fluoride-contaminated groundwater for potable requirements. The fluorosis problem is severe in India as almost 80% of the rural population depends on untreated groundwater for potable water supplies. A new method to treat fluoride-contaminated water using magnesium oxide has been developed at IISc. The IISc method relies on precipitation, sedimentation, and filtration techniques and is efficient for a range of groundwater chemistry conditions.

Monitoring of glacial mass balance in the Baspa basin using accumulation area ratio method

Abstract: In the Himalaya, glacier and snow-melt form an important source of water into the North Indian ri vers. However, this source of water is not permanent as glacial dimensions change with climate. One of the important parameters to model future changes in glacial extent is the mass balance. In this communication an attempt has been made to calculate the mass balance for 19 glaciers in Himachal Pradesh using accumulation area ratio (AAR) method. A regression relationship between AAR and specific mass balance was developed using field data from 1982 to 1988 for Shaune Garang glacier and 1976 to 1984 for Gor Garang glacier. Regression analysis suggests good correlation between AAR and specific mass balance with r 2 as 0.80. AAR for 2000 and 2001 was estimated for 19 glaciers in the Baspa basin by systematic weekly analysis of WiFS images of Indian Remote Sensing satellite from May to September. Mass balance was estimated during 2001 and 2002 for 19 gl aciers in the basin, suggesting overall specific mass balance value of – 90 and – 78 cm, respectively. The investigations suggest a loss of 0.2347 km 3 of glacial ice in the last two years. The investigation has shown that four glaciers have no accumulation area, as these are located in lower -altitude zones. These glaciers are expected to face terminal retreat due to lack of formation of new ice. This is likely to pose serious problem of availability of water to many villages located in the Baspa basin.

Performance of Bt cotton (MECH-162) under Integrated Pest Management in farmers' participatory field trial in Nanded district, Central India

Abstract: Farmers' participatory field trail was conducted in 3318 ha representing rainfed cotton-growing region in Nanded district of the central zone, to evaluate the performance of Bt cotton hybrid MECII-162 under Integrated Pest Management (IPM), and to compare it with conventional cotton (CC) hybrids/varieties grown with and without IPM There was significant reduction in bollworm incidence, particularly the American bollworm (Heliocoverpa armigera) and pink bollworm (Pectinophora gossypiella) and the damage caused by them to the fruiting bodies in Bt MECH-162 compared to CC with IPM In Bt MECH-162, 115% of the fruiting bodies were damaged compared to 294% in CC with IPM Maximum damage was observed in CC without IPM, where seven sprays of pesticides were made for control of insect pests in comparison to three on Bt MECH-162 Population of the sucking pests and two natural enemies monitored was also lower in Bt MECH-162 compared to CC The latter without IPM recorded the lowest population of natural enemies Seed cotton yield (124 q/ha), and net returns (Rs 16231/ha) were highest for Bt MECH-162 CC under IPM recorded an yield of 71 q/ha, and return of Rs 10507/ha The results show that IPM in cotton was most effective with Bt MECH-162, and provided higher return though the initial seed cost for the farmers was higher

Isolation, characterization and antimicrobial activity of marine halophilic Actinopolyspora species AH1 from the west coast of India

Abstract: A halophilic Actinopolyspora species AH1 was isolated from a marine sediment sample obtained from Alibag coast, Maharashtra. The strain showed good growth in medium containing 10 to 15% (w/v) NaCl and with 30 to 36°C temperature. Cultural properties of Actinopolyspora were studied extensively on starch casein agar and other media. Strain AH1 showed an elongated and circular shape with 20 to 30 spore-chain structures observed by slide culture technique and scanning electron microscopy. The morphological, biochemical and physiological characters of the isolate conformed to the characteristics of the genus Actinopolyspora, which contained only three species, viz. A. halophila, A. mortivallis and A. iraqiensis. However, the Actinopolyspora species AH1 isolated and characterized by us showed different properties compared to the known species. It showed resistance to clindamycin, vancomycin, nalixidic acid and streptomycin antibiotics. Interestingly, it showed good antibacterial activity against Staphylococcus aureus, S. epidermidis, Bacillus subtilis and antifungal activities against Aspergillus niger, A. fumigatus, A. flavus, Fusarium oxysporum, Penicillium species and Trichoderma species. This is a report of the antimicrobial activity exhibited by Actinopolyspora species AH1 isolated from the marine sediment.

Sustainable biomass power for rural India: case study of biomass gasifier for village electrification.

Abstract: The performance and impact of a decentralized biomass gasifier-based power generation system in an unelectrified village are presented. In Hosahalli village, Karnataka, India, lighting, drinking water, irrigation water and flour-milling services are provided using power derived from the biomass gasifier-based power generation system. The system consists of a 20 kW gasifier-engine generator system with all the accessories for fuel processing and electricity distribution.The biomass power system has functioned for over 14 years (1988–2004) in Hosahalli village (population of 218 during 2003), meeting all the electricity needs of the village. Lighting and piped drinking water supply using biomass electricity, was provided for over 85% of the days during the past six years. The fuel, operation and maintenance cost ranged from Rs 5.85/kWh at a load of 5 kW to Rs 3.34/kWh at a load of 20 kW. Technical, social, economic and management-related lessons learnt are presented here.

Shaking table tests in earthquake geotechnical engineering

Abstract: Research in earthquake geotechnical engineering has shown considerable development in the recent past. We focus here on developments of model testing in earthquake geotechnical engineering. Two aspects of model testing are given importance, namely manual shaking table and laminar box. Design, development, calibration and performance of these equipments are described. Model testing is the essential requirement of earthquake geotechnical engineering that helps in understanding the behaviour of geotechnical facilities and their performance during earthquake. Manual shaking table developed very economically can be used as an alternative to a more sophisticated shaking table. Laminar box is a sophisticated container which can enhance the accuracy in assessing the ground behaviour. Some of the important calibration techniques necessary are also discussed.

Recession and morphogeometrical changes of Dokriani glacier (1962-1995) Garhwal Himalaya, India

Abstract: Dokriani glacier is one of the well -developed, m ediumsized (7.0 km 2 ) valley glaciers of Gangotri group of glaciers in the Garhwal Himalaya. The glacier was originally mapped in 1962 –63 and was remapped in 1995 by the Survey of India. The snout, surface area and elevation changes were determined by a comparison of these two topographic maps and fieldwork. The glacier shows rapid frontal recession, substantial thinning at the lower elevation and reduction of gl acier area and volume. Between 1962 and 1995, glacier volume is estimated to have been reduce by about 20% and frontal area had vacated by 10%. The study revealed that during the period 1962–1995 the glacier has receded by 550 m with an average rate of 16.6 m/yr. However, the yearly monitoring of snout position of the glacier during 1991–1995 revealed an average rate of recession of 17.4 m/yr and has vacated an area of 3957 m 2 . GLACIERS are dynamic and fragile ice bodies on the lan dscape and are products of the climate and climatic changes. Change in climate is clearly reflected in mass and te mperature changes of glaciers. Hence the perennial land ice bodies are considered the key for climate system stu dies

Sustainable building technologies

Abstract: The paper addresses certain issues pertaining to the energy, environment, alternative building technologies and sustainable building construction. Brief history of developments in building materials is discussed. Energy consumption in manufacture and transportation of some common and alternative building materials and the implications on environment are presented. Brief details of some of the energy-efficient alternative building technologies developed by ASTRA are provided. Impacts of alternative building technologies on energy and environment are discussed. Some thoughts about utilizing industrial and mine wastes as well as recycling of building wastes for meeting the demand for buildings in a sustainable fashion have also been presented.

Inventory of methane and nitrous oxide emissions from agricultural soils of India and their global warming potential

Abstract: Agricultural soils contribute towards the emission of methane and nitrous oxide, the two important greenhouse gases causing global warming. Due to the diverse soil, land-use types and climatic conditions, there are uncertainties in quantificatio n of greenhouse gas emission from agricultural soils in India. An inve ntory of the emission of methane and nitrous oxide from different states in India was prepared using the methodology given by the Inter-Governmental Panel on Climate Change. For methane emission, state-specific emission coefficients have been used for all major rice ecosystems. In case of nitrous oxide, both direct and indirect emissions from agricultural soils in different states have been calculated using the emission coeff icients derived from the experiments conducted in India. For the base year 1994–95, methane and nitrous oxide emissions from Indian agricultural fields were est imated to be 2.9 Tg (61 Tg CO2 equivalent) and 0.08 Tg (39 Tg CO2 equivalent) respectively.