Showing papers in "Current Science in 2008"

Biosurfactants : Properties, commercial production and application

Abstract: Biosurfactants or microbial surfactants are surface-active biomolecules that are produced by a variety of microorganisms. Biosurfactants have gained importance in the fields of enhanced oil recovery, environmental bio-remediation, food processing and pharmaceuticals owing to their unique properties such as higher biodegradability and lower toxicity. Interest in the production of biosurfactants has steadily increased during the past decade. However, large-scale production of these molecules has not been realized because of low yields in production processes and high recovery and purification costs. This article describes some practical approaches that have been adopted to make the bio-surfactant production process economically attractive. These include the use of cheaper raw materials, optimized and efficient bioprocesses and overproducing mutant and recombinant strains for obtaining maximum productivity. Here, we discuss the role and applications of biosurfactants focusing mainly on medicinal and therapeutic perspectives. With these specialized and cost-effective applications in biomedicine, we can look forward to biosurfactants as the molecules of the future.

Materials for next-generation lithium batteries

Abstract: Likely developments awaiting the science and technology of next-generation lithium batteries form the focus of this article. New anode materials based on nano-structured carbons and lithium-alloying metals, novel eco-friendly cathode materials, safe and non-flammable aprotic electrolytes, and polymer electrolytes are discussed. Possible scenarios for improvements in existing or presumed battery active materials are suggested. Advances in the science and technology of lithium batteries are previewed with a prognosis of challenges and opportunities in the development of marketable materials and products.

Effect of increasing temperature on yield of some winter crops in northwest India

Abstract: The effect of increase in temperature on grain yield of some winter crops (wheat, mustard, barley and chickpea) in northwest India was evaluated on the basis of historic records and through a dynamic crop growth model, WTGROWS. The optimal date of sowing was also evaluated in view of the increase in seasonal temperature. The yield of these crops, especially wheat, already showing signs of stagnation in most places of northwest India, is most likely to be affected by temperature changes. The solar radiation-temperature interactions study in wheat reveals some interesting trends and is seen to vary from one location to another. Keeping in view the trends in global climate change, a shift in sowing time, as an adaptation strategy is recommended. The simple and empirical relations between yield and seasonal temperature change can be well used for a crude estimate of yield dependence of temperature rise of these winter crops.

Antidiabetic activity of Aloe vera and histology of organs in streptozotocin-induced diabetic rats

Abstract: An attempt was made to study the beneficial effects of Aloe vera (L.) Burm. fil. in streptozotocin-induced diabetic rats. In diabetic induced rats fed with A. vera (300 mg/kg body wt), the fasting plasma glucose levels were reduced to normal and body weight was found to be increased. In the pancreatic sections of diabetic rats fed with A. vera, the islets were comparable to normal rats. In liver, the changes caused after induction of diabetes are granular cytoplasm, dilated sinusoids, shrunken nuclei and inflammation, which was reduced after feeding with A. vera. Excess proliferation of epithelium in the small intestine was observed in diabetic rats, which was reduced after A. vera feeding. In diabetic rats and diabetic rats fed with A. vera, no change was noticed in the kidney and stomach.

RF plasma-treated polymers for biomedical applications

Abstract: N. Gomathi, A. Sureshkumar and Sudarsan Neogi* The choice of polymers for various biomedical applications depends on their surface properties. All polymers do not possess the surface properties required for biomedical applications. Surface prop-erties of the materials like surface free energy, hydrophilicity and surface morphology, which influ-ence the cell–polymer interaction, decide the choice of the polymer. Radio frequency (RF) plasma offers a unique route for surface modification of polymers without affecting their bulk properties. This process results in a smooth, pinhole-free ultrathin film. Plasma treatment of polymers can render the material surface either hydrophilic or hydrophobic through the use of the respective plasma gases. It has found various applications in automobile, electronic, biomedical and chemical industries. In this article the properties and effects of RF plasma treatment of polymers are dis-cussed with reference to their biomedical applications, such as in body implants, bioseparation, sterilization, biosensors, ophthalmology, etc.

Time and dose-dependent antimicrobial potential of Ag nanoparticles synthesized by top-down approach

Abstract: Silver nanoparticles are known to be good antibiotic agents. In this study, silver (Ag) nanoparticles (∼6 nm) were synthesized using electro-exploding wire (EEW) technique. Antibacterial action of Ag nanoparticles was studied both in liquid and solid phase using colony-forming unit (CFU) detection. Time and dose-dependent study of Ag nanoparticles shows that the effectiveness of particles increases with increasing particle dose and treatment time. This effect was dose-dependent and more pronounced against Gram-negative bacteria compared to Gram-positive bacteria. Transmission electron microscopy result shows particle binding with bacterial cell membrane. Membrane potential assay and cytoplasm diffusion assay show the effectiveness of Ag nanoparticle used in this study.

Soil carbon storage capacity as a tool to prioritize areas for carbon sequestration

Abstract: Carbon dioxide (CO 2 ), one of the major components of greenhouse gases, is of major concern in terms of the global warming phenomenon. To mitigate the effect of atmospheric CO 2 , carbon capture and storage (CCS) has been found to be an important tool. The present study aims at explaining the role of soils as one of the most important natural resources in enhancing CCS. Soils capture and store both organic and inorganic forms of carbon and thus act both as source and sink for atmospheric CO 2 . The datasets developed on CCS of soils permit us to generate thematic maps on soil carbon stocks, which may serve as ready reckoners for planners in prioritizing C sequestration programmes.

Natural anthocyanins as photosensitizers for dye-sensitized solar devices

Abstract: Different natural pigments containing anthocyanins extracted from tropical flowers were studied as possible sensitizers for TiO 2 by assembling dye-sensitized solar cells (DSCs). Photocurrent densities ranging from 1.1 to 5.4 mA cm -2 were obtained with photovoltages ranging from 390 to 410 mV. The overall efficiency and fill factor of these cells varied from 0.2 to 1.1 and 53 to 64 respectively. Among the flower pigments studied, the extract from Hibiscus surattensis-HST (cultivated species/colour of the flower: magenta) gave the best photosensitized effect, which can be used as an environment-friendly, low-cost alternative system, especially for educational purposes.

Performance analysis of numerical schemes in highly swirling turbulent flows in cyclones

Abstract: The aim of this study is to investigate the suitability of various numerical schemes and turbulence models in highly complex swirling flows which occur in tangential inlet cyclones. Three-dimensional steady governing equations for incompressible turbulent flow inside a cyclone were solved numerically using Fluent CFD (computational fluid dynamics) code. The Reynolds stress turbulence model, the Standard k-e and the RNG k-e turbulence models together with various combinations of numerical schemes are used to obtain axial and tangential velocity profiles, pressure drop and turbulent quantities. Computational results were compared with experimental and numerical values given in the literature, so as to evaluate the performance of the numerical schemes and turbulent models. Comparison of CFD results with experimental data shows that the Reynolds Stress turbulence model yields a reasonably good prediction. Results obtained from the numerical tests have demonstrated that the use of the Presto interpolation scheme for pressure, the Simplec algorithm for pressure-velocity coupling and the quadratic upstream interpolation for convective kinetics (quick) scheme for momentum variables gives satisfactory results for highly swirling flows in cyclones.

Molecular physiology of plant nitrogen use efficiency and biotechnological options for its enhancement

Abstract: Nitrogen use efficiency (NUE) in plants is a complex phenomenon that depends on a number of internal and external factors, which include soil nitrogen availability, its uptake and assimilation, photosynthetic carbon and reductant supply, carbon-nitrogen flux, nitrate signalling and regulation by light and hormones, to name a few. The molecular basis for organism-wide regulation of nitrate assimilation is not yet fully understood, and biotechnological interventions to improve crop NUE have met with limited success so far. This article summarizes the physiological, biochemical and molecular aspects of NUE, QTL mapping studies as well as transgenic efforts to improve it in crop plants and model plants. It encompasses primary and secondary N-assimilatory pathways and their interplay with carbon metabolism, as well as signalling and regulatory components outside the metabolic cascade. The article highlights the need for an integrated approach combining fertilizer management techniques with biotechnological interventions to improve N flux and NUE for Indian crop cultivars.

Spatial variability of soil properties and its application in predicting surface map of hydraulic parameters in an agricultural farm

Abstract: Knowledge of spatial variation of soil properties is important in precision farming and environmental modelling. Spatial distribution of water content at field capacity (FC) and permanent wilting point (PWP) at different zones of a farm governs the available water for plant growth. These two soil hydraulic parameters play key roles in crop selection for different blocks of a farm, and in scheduling irrigation of crops in a field. In this study, spatial variation of bulk density organic carbon, silt and clay contents for two soil depths (0-15 and 15-30 cm) in the agricultural farm of the Indian Agricultural Research Institute, New Delhi were quantified and the respective surface maps were prepared through ordinary kriging. Particle size distribution shows better spatial correlation structure than bulk density and organic carbon content. Gaussian model fits well with experimental semivariogram of bulk density, and silt and clay contents. Hole-effect model was found to be the best to fit the experimental semivariogram of organic carbon content. Spatial correlation structure for both surface (0-15 cm) and subsurface (15-30 cm) soil layer remains the same, but the magnitude of spatial correlation differs. Cross-validation of the kriged map shows that spatial prediction of basic soil properties using semivariogram parameters is better than assuming mean of observed value for any unsampled location. Pedo-transfer functions were coupled with the surface map of basic soil properties to generate a map of water content at FC and PWP. Evaluation of spatial maps of θ FC and θ PWP showed reasonable accuracy of these two hydraulic parameters for farm-level or regional-scale application.

Changing streamflow patterns in the rivers of northwestern Himalaya : Implications of global warming in the 20th century

Abstract: The results of trend analyses of the discharge data of four rivers in northwestern Himalaya, namely Beas, Chenab, Ravi and Satluj, are presented here and the impact of climate change in the last century is discussed. In the case of Satluj river, studies indicate an episodic variation in discharge in all three seasons on a longer timescale of about 82 years (1922–2004). Statistically significant decrease in the average annual and monsoon discharge and insignificant increase in winter and spring discharge, despite increasing temperatures during all the three seasons can also be seen. Decreasing discharge during winter and monsoon seasons in the post-1990 period, despite rising temperatures and average monsoon precipitation strongly indicates decreasing contribution of glaciers to the discharge and their gradual disappearance. On a shorter timescale of the last four decades of the 20th century, barring the Beas river, which shows a significantly decreasing trend, the other three rivers have shown a statistically insignificant change (at 95% confidence level) in their average annual discharge. Annual peak flood discharges show significant increasing trends in the Satluj and Chenab basins, significant decreasing trend in the Beas river and insignificant trend in the Ravi river. Notwithstanding these variations, the studies indicate an increase in the number of ‘high-magnitude flood’ events in the rivers in northwestern Himalaya in the last three decades.

The endophytic fungal complex of Catharanthus roseus (L.) G. Don

Abstract: Catharanthus roseus (L.) is well known for its production of several anticancerous vinca alkaloids such as vincristine, vindesine, vinorelbine, vinblastin, and the recently discovered vinflunine. This plant is a host to a plethora of endophytic fungi. A total 183 endophytic fungi representing 13 fungal taxa were isolated from leaf, stem and root tissues of C. roseus from two sites representing two different ecosystems in North India. Interestingly, with two exceptions (one coelomycete and one ascomycete), all of the isolates were Hyphomycetes. Root tissues were heavily colonized by genera such as Alternaria, Cladosporium and Aspergillus. However, leaf tissues showed a greater diversity of endophytes and Drechslera, Curvularia, Bipolaris, Alternaria and Aspergillus spp. were the dominant fungi isolated. Interestingly, a fungus producing no fruiting structures was the most prevalent, isolated from C. roseus. On the basis of its partial ITS-5.8 S rDNA sequences, it was identified as Chaetomium globossum, with 99% sequence similarity (537/540). The species richness as well as frequency of colonization of endophytic fungi were pronounced in the root tissues at both sites (Loc 1, 38.6%; Loc 2, 33.7%). This study suggests that endophytes are both host- and tissue-specific. It also confirms that despite ecological variations, there were little differences in the species richness of fungal endophytes recovered from plants in the two different ecological sites.

Indian summer monsoon in future climate projection by a super high-resolution global model

Abstract: The impact of future climate change on the Indian summer monsoon has been investigated using a super high-resolution global general circulation model. The model with approximately 20-km mesh horizontal resolution can resolve features on finer spatial scales, which were till now resolved by employing high-resolution regional models. Regional models are known to have high dependency on the lateral boundary forcing and significant inability to represent regionalglobal scale interactions comprehensively. Another advantage of the 20-km global model is its fidelity in representing the regional distribution of the present-day monsoon rainfall. Super high-resolution future scenario for the Indian summer monsoon shows widespread but spatially varying increase in rainfall over the interior regions and significant reduction in orographic rainfall over the west coasts of Kerala and Karnataka and the eastern hilly regions around Assam. Over these regions, the drastic reduction of wind by steep orography predominates over the moisture build-up effect (that causes enhanced rainfall over other parts) in reducing the rainfall. This indicates that monsoon rainfall is strongly controlled by parameterized physics and high-resolution processes which need to be resolved with adequately high resolution. The model projects substantial, spatially heterogeneous increase in both extreme hot and heavy rainfall events over most parts of India by the end of the century. While fine-scale surface moisture feedbacks influence the response of extreme hot events, extreme precipitation is influenced by fine-scale orography, evaporation, moisture content and circulation. Thus, the results indicate that consideration of fine-scale processes is critical for accurate assessment of local and regionalscale vulnerability to climate change.

Fluxes of methane and nitrous oxide from an Indian mangrove

Abstract: Fluxes of greenhouse gases, CH 4 and N 2 O, were measured from a mangrove ecosystem of the Cauvery delta (Muthupet) in South India. CH 4 emissions were in the range between 18.99 and 37.53 mg/sq. m/d, with an average of 25.21 mg/sq. m/d, whereas N 2 O emission ranged between 0.41 and 0.80 mg/sq. m/d (average of 0.62 mg/sq. m/d). The emission of CH 4 and N 2 O correlated positively with the number of pneumatophores. In addition to the flux measurements, different parts of the roots of Avicennia marina were quantified for CH 4 concentration. Invariably in all the seasons, measured CH 4 concentrations were high in the cable roots, with gradual decrease through the pneumatophores below water level and the above water level. This clearly indicates the transport of CH 4 through the roots. We were able to establish that CH 4 was released passively through the mangrove pneumatophores and is also a source to the atmosphere. We present some additional information on transport mechanisms of CH 4 through the pneumatophores and bubble release from the mangrove ecosystems.

Bioinvasion of Kappaphycus alvarezii on corals in the Gulf of Mannar, India.

Abstract: Kappaphycus alvarezii (Doty) Doty (Rhodophyta: Solieriaceae) is a Philippine-derived macroalga introduced into the Gulf of Mannar Marine Biosphere Reserve, South India for mariculture in 2000. Here we report its bioinvasion on branching corals (Acropora sp.) in the Kurusadai Island. Qualitative data collected using underwater photography clearly indicated its invasion and establishment on live and dead corals as well as coral rubbles and pavements. It specifically invaded Acropora sp. as monospecific beds with extraordinary phenotypic plasticity in the form of thallus, thickness of its major axis and lateral branching. It shows remarkable shadowing and smothering effects over the coral colonies. The primary and secondary branches are much reduced in the invaded algal colonies. Quantitative data on its live cover on corals and biomass production are also reported. These observations are discussed with available limited information on bioinvasion of K. alvarezii on coral reefs. Our findings disprove all arguments and misapprehensions reported earlier about this species as coral-friendly and as a safe candidate for mariculture for the production of carrageenan under wild conditions in the Gulf of Mannar. Our observations underscore the need for urgent reconsideration of its cultivation in a biologically diverse ecosystem, the Gulf of Mannar.

Stilbenes with tyrosinase inhibitory activity

Abstract: Tyrosinase (EC 1.14.18.1) is a multicopper monooxygenase enzyme with wide distribution. In mammals, it is responsible for pigmentation of skin, eyes and hair. The enzyme is involved in the undesired browning of bruised or cut fruits and vegetables. In insects, tyrosinase is one of the key enzymes in the molting process. Investigation of inhibitors of this enzyme may lead to development of novel skin whitening agents, anti-browning substances or insect control compounds. A number of naturally occurring stilbenes have been shown to possess strong tyrosinase inhibitory potential. Results from the studies on several natural and synthetic analogues have indicated that the number of free OH groups and their positions on the aromatic rings are important for the activity. This review gives a brief overview of the enzyme and describes tyrosinase-inhibiting stilbenoids regarding their botanical origin, structure-activity relationships, mechanisms of action and practical applications.

Simulation of a severe thunderstorm event during the field experiment of STORM programme 2006, using WRF-NMM model

Abstract: In the tropics, most of the extreme weather events are convective in nature Many parts over the Indian region experience thunderstorms at higher frequency during the pre-monsoon months (March-May), when the atmosphere is highly unstable because of high temperatures prevailing at lower levels During April and May, the eastern and northeastern parts of the country, ie Gangetic West Bengal, Jharkhand, Orissa, Bihar, Assam and parts of other northeastern states are affected by higher frequency of severe thunderstorms, locally named as 'Kal-baishakhi' or 'Nor'westers' Realizing the importance of better understanding and prediction of these severe local storms over east and northeast India and their socio-economic impact, the Department of Science and Technology, Government of India organized a national coordinated programme on 'Severe Thunderstorm Observation and Regional Modelling (STORM)' to be carried out in the pre-monsoon season of 2006-10 Mesoscale models are essential for the accurate prediction of such high-impact weather events In the present study, an attempt has been made to simulate one thunderstorm event that occurred on 20 May 2006 at Kolkata (2252°N, 8837°E) during the field experiment of STORM 2006, using Non-hydrostatic Mesoscale Model (NMM) core of the Weather Research and Forecasting (WRF) system with different initial conditions This model has been developed by the National Oceanic and Atmospheric Administration/National Centers for Environment Prediction The model results are validated with STORM field experiment data The model performed well in capturing stability indices, which act as indicators of severe convective activity along with the thunder-storm-affected parameters as in the observations The results of these analyses show that the 3 km WRF-NMM has better capability when it comes to thunderstorm simulation This suggests that high-resolution models have the potential to provide unique and valuable information for severe thunderstorm forecasters

Forest conservation, afforestation and reforestation in India: Implications for forest carbon stocks

Abstract: This article presents an assessment of the implications of past and current forest conservation and regeneration policies and programmes for forest carbon sink in India. The area under forests, including part of the area afforested, is increasing and currently 67.83 mha of area is under forest cover. Assuming that the current trend continues, the area under forest cover is projected to reach 72 mha by 2030. Estimates of carbon stock in Indian forests in both soil and vegetation range from 8.58 to 9.57 GtC. The carbon stock in existing forests is projected to be nearly stable over the next 25 year period at 8.79 GtC. However, if the current rate of afforestation and reforestation is assumed to continue, the carbon stock could increase from 8.79 GtC in 2006 to 9.75 GtC by 2030 - an increase of 11%. The estimates made in this study assume that the current trend will continue and do not include forest degradation and loss of carbon stocks due to biomass extraction, fire, grazing and other disturbances.

Temporal changes in rate of recession : Evidences from Satopanth and Bhagirath Kharak glaciers, Uttarakhand, using Total Station Survey

Abstract: Snouts of Satopanth and Bhagirath Kharak glaciers, located at the head of the Alaknanda valley in Chamoli District, Uttarakhand, were monitored using Total Station Survey. Retreat of the snouts and area vacated by recession of the glaciers were estimated for 44 years by way of superimposing the Survey of India to-posheet of 1962 on the map prepared by Total Station Survey in 2006. The total area vacated by the Satopanth and Bhagirath Kharak glaciers during 44 years was 313,923.14 sq. m (0.314 sq. km) and 129,369.16 sq. m (0.13 sq. km) respectively. The annual average retreat of the snout of the Satopanth glacier between 1962 and 2005 (43 years) was estimated as 22.88 m/yr, whereas retreat was low (7.42 m/yr) for the Bhagirath Kharak glacier. Interestingly, actual field measurements for the year 2005-06, showed an estimated retreat of 6.5 and 1.5 m/yr for the Satopanth and Bhagirath Kharak glaciers respectively. Snouts of the Satopanth and Bhagirath Kharak glaciers recorded continuous recession for the past four decades, with decline in recession of both cases. Both glaciers are situated in the same basin and experience similar climatic conditions. However, different recession rates of glaciers are attributed to unequal distribution of tributary glaciers, active cirques, drainage characteristics, density and distribution of supraglacial debris over the glacier surface.

Bioenergetic cost of heat tolerance in wheat crop

Abstract: Decline in national wheat productivity, and stagnation of yield in the national Advanced Varietal Trials in the past decade are partly attributed to high temperature stress during the period of grain-filling. In view of the predicted global warming, terminal heat stress is likely to increase. Heat shock proteins (HSPs) synthesized to cope with the heat stress in different organisms are known to provide protection and repair the cellular damage caused by heat. The production cost of HSPs from different plant species - wheat, Arabidopsis, Phaseolus and maize ubiquitin was calculated based on their reported amino acid composition, and the production value of individual amino acids published earlier. Glucose required for the production of wheat HSP 101 was 20% higher compared to the storage proteins in wheat grains. Thus, incorporation of terminal heat tolerance into high-yielding cultivars will have an energetic cost, and would require additional carbon assimilates and N inputs.

Land-use and land-cover change and future implication analysis in Manas National Park, India using multi-temporal satellite data

Abstract: The Manas National Park is an important conservation area in the Bhabhar and flood plain ecosystem of Northeast India. Satellite imageries of 1977, 1998 and 2006 were analysed to detect the change in habitat types with the help of remote sensing and geographic information system tools. Results indicate landscape-level changes in the vegetation and overall habitat quality within the Park. There is a substantial increase in savannah grassland (74.6%) accompanied by decline in alluvial grasslands (46.8%) from 1977 to 2006. A total of 20.47 km 2 has also been encroached during this period. Water sources in the Park have declined and there has been a significant shift towards a drier and woodland type of vegetation. These land-use changes were a result of non-implementation of habitat management/manipulation activities that are a prerequisite for supporting viable populations of specific endangered animal species in a given Protected Area. In this communication, we recommend a set of habitat management activities for restoration of key habitats in Manas.

Volatiles as priming agents that initiate plant growth and defence responses

Abstract: Plants are exposed to attack by pathogens and insect pests For protection against this stress, plants have evolved defensive strategies to counteract potential invaders In the present review comparisons are drawn between herbivores-induced plant volatiles as an elicitor of plant defences and two other classes of signalling molecules, C6 green-leaf volatiles and C4 bacterial volatiles, which appear to prime plant defences thereby enhancing the capacity to mobilize cellular defence responses when plants are faced with herbivore/pathogen attacks Several chemical changes in the soil are associated with plant growth-promoting rhizobacteria wherein particularly, the volatile components, 2,3-butanediol and acetoin are released extensively that trigger the maximum level of growth promotion

A comparative study on performance of MM5 and WRF models in simulation of tropical cyclones over Indian seas

Abstract: Tropical cyclone is one of the most devastating and deadly weather phenomenon worldwide. It is a result of organized intense convective activities over warm tropical oceans. In recent years mesoscale models are extensively used for simulation of genesis, intensification and movement of tropical cyclones. In this study, the recent three very severe cyclonic storms generated over Indian seas (Bay of Bengal and Arabian Sea) are considered. During 26-29 April 2006, a very severe tropical cyclone, known as Mala, developed over the Bay of Bengal and crossed the Arakan coast of Myanmar on 29 April 2006. During 2-7 June 2007, a super cyclonic storm, known as Gonu, developed over the Arabian sea and crossed the Makran coast on 7 June 2007. During 11-16 November 2007, a very severe cyclonic storm, known as Sidr, developed over the Bay of Bengal and crossed the Khulna-Barisal coast of Bangladesh on 15 November 2007. In the present study, two state-ofthe- art mesoscale models, MM5 and WRF, developed at the National Center for Atmospheric Research (NCAR), USA, have been used to evaluate the performances of both the models in the simulation of the above-mentioned tropical cyclones. The performances of both the models have been calculated by integrating with 15 different initial conditions, i.e. each case with five different initial conditions. A number of meteorological fields, viz. central pressure, wind and precipitation have been verified against observations/ verification analyses. The vector displacement error in track forecast has also been calculated using the best track provided by the India Meteorological Department. The results indicate that the WRF model has better performance in respect of track and intensity prediction than the MM5 model.

Estimation of retreat rate of Gangotri glacier using rapid static and kinematic GPS survey

Abstract: The Gangotri glacier is retreating like other glaciers in the Himalaya and its volume and size are shrinking as well. Reoccupying the historical snout positions using Global Positioning System (GPS) in rapid static mode indicates the varying rates of retreat during different time-spans of the last century, with the total retreat of 1519.13 m in the last 69 years. Post 1971, the rate of retreat of the glacier has declined. Monitoring of glacier terminus using GPS survey in kinematic mode reveals that the glacier has retreated at much lower rate (12.10 ± 0.041 ma -1 ) between 2004 and 2005. The study further shows that the southern portion of the snout is retreating at significantly lower rate in comparison to the northern part. However, maximum recession (13.76 ± 0.048 m in 2004-05) took place along the centreline of the glacier.

Introduction of the American grey squirrel (Sciurus carolinensis) in Europe : a case study in biological invasion

Abstract: The introduction of the eastern grey squirrel (native to America) in Europe is causing a dramatic decline in the range of the native European red squirrel, due to competition. Grey squirrels compete with the native species mainly for food; furthermore, they can maintain and spread a poxvirus, which causes a lethal disease in red squirrels in Britain. According to some modelling scenarios, grey squirrels will spread from Italy to France and Switzerland in the next 20-30 years, and to a large part of Eurasia in the long term. This would represent a serious threat for the survival of the red squirrel throughout its range. This case study of biological invasion suggests that the risks posed by the introduced species may be minimized with a reduction in animal trade between countries and using a procedure of risk-assessment for every imported species.

Prioritization of sub-watersheds for sustainable development and management of natural resources: An integrated approach using remote sensing, GIS and socio-economic data

Abstract: The study area is one of the watersheds of North Pennar basin, covering an area of 570 km(2) and lies between latitude 13 degrees 55'-14 degrees 17'N and longitude 77 degrees 05'-77 degrees 25'E in Pavagada area, Tumkur District, Karnataka and a small portion in Ananthpur District, Andhra Pradesh, India, forming a part of the hardrock terrain The drainage network shows dendritic to sub-dendritic pattern and is non-perennial in nature Poor soil cover, sparse vegetation, erratic rainfall and lack of soil moisture characterize the area for most part of the year Recurring drought coupled with increase in groundwater exploitation results in decline the groundwater level The entire study area has been further divided into nine sub-watersheds, namely Byadanur, Devadabetta, Talamaradahalli, Gowdatimmanahalli, Naliganahalli, Nagalamadike, Maddalenahalli, Paluvalli tank and Dalavayihalli, ranging in geographical area from 49 to 75 km(2) It has been taken up for prioritization based on available natural resources derived from satellite images and socio-economic conditions, including drainage density, slope, water yield capacity, ground-water prospects, soil, wasteland, irrigated area, forest cover and data on agricultural labourers, SC/ST population and rainfall On the basis of priority and weightage assigned to each thematic map, the sub-watersheds have been grouped into three categories: high, medium and low priority The prioritization results reveal that Nagalamadike, Maddalenahalli and Dalavayihalli sub-watersheds rank highest on the basis of weightage and are considered as high priority These sub-watersheds may be taken up with development and management plans to conserve natural resources on sustainable basis with immediate effect, which will ultimately lead to soil and water conservation

The worldwide threat of antimicrobial resistance

Abstract: Antibiotics have undoubtedly made a major contribution to improvements in both human and animal health and welfare. The recent years have brought an alarming rise in the prevalence of resistance to some agents among certain groups of bacteria. Concern is growing that therapeutic options will become increasingly limited if resistance rates continue to rise. There is widespread agreement that action is required to reverse or at least slow down this process. Necessary steps to manage the situation include better surveillance to assess accurately the extent of the problems, more prudent use of the available antibiotics to conserve valuable therapeutic resources and improved infection control to limit the spread of resistant organisms. Achieving these goals will not be possible without the government, medical professionals and public being better informed and educated. Regulatory bodies and the pharmaceutical industry need to work together to ensure a steady supply of new antimicrobials. Our understanding of the processes driving resistance at both the molecular and population levels is advancing. However, the relative contributions of the various uses of antimicrobials to the resistance problem and which will be the most effective containment measures are still hotly debated. Progress is being made, but continued concerted action is necessary if the usefulness of this most important group of therapeutic agents is to be preserved. Developing countries have an important role to play... eventually the non-prescription availability of agents will have to be addressed.

Nitrogen cycling : A review of the processes, transformations and fluxes in coastal ecosystems

Abstract: The coastal and marine nitrogen cycle occupies a complex, central role within the biogeochemical cycles. Human interventions in the earth system have risen to unprecedented levels, strongly influencing the global nitrogen cycle. The nitrogen cycle in the open ocean compared to coastal ecosystems appears to have remained unharmed, although recent observations have shown increasing anthropogenic influence. Projections suggest that global nitrogen cycle is being altered either directly by the continued addition of anthropogenically created fixed nitrogen to the earth system and its cascading effects, or indirectly through anthropogenically induced climate change. These alterations have the potential to cause positive feedbacks in the climate system, but they are neither well understood nor quantified. In the atmosphere, concentrations of the greenhouse gas, nitrous oxide and of the nitrogen-precursors of smog and acid rain are increasing. This unprecedented nitrogen loading has contributed to long-term decline in coastal fisheries. This article reviews some of the major processes, transformations and fluxes of nitrogen in the coastal ecosystems with reference to mangroves, occurring naturally and also due to human perturbations.

Detection of biomarker in breath: A step towards noninvasive diabetes monitoring

Abstract: Along with more than two hundred volatile organic compounds (VOCs), acetone is also a normal constituent of breath of healthy individuals, albeit in the sub-ppm range, and its concentration increases in diabetic patients. Considering the importance of breath acetone as a biomarker of diabetes, some studies have already been made to measure breath acetone concentration (and correlate with blood sugar level) using GC-MS. There are a few reports of measuring breath acetone concentration using semiconductor sensor in the background of air (i.e. in the absence of VOCs present in normal breath and hence the question of selectivity remains in the real situation) and at a higher concentration (above 10 ppm). We report excellent sensitivity of sonochemically prepared nanosized gamma-Fe2O3 sensors towards sub-ppm acetone (pathological range) in the background of human breath. Our preliminary results should stimulate further research towards developing cheap, rugged and compact semiconductor sensors for noninvasive monitoring of diabetes.