Showing papers by "Banaras Hindu University published in 2006"

Impact of Climate Change on Indian Agriculture: A Review

Abstract: During the recent decade, with the growing recognition of the possibility of climate change and clear evidence of observed changes in climate during 20th century, an increasing emphasis on food security and its regional impacts has come to forefront of the scientific community In recent times, the crop simulation models have been used extensively to study the impact of climate change on agricultural production and food security The output provided by the simulation models can be used to make appropriate crop management decisions and to provide farmers and others with alternative options for their farming system It is expected that in the coming decades with the increased use of computers, the use of simulation models by farmers and professionals as well as policy and decision makers will increase In India, substantial work has been done in last decade aimed at understanding the nature and magnitude of change in yield of different crops due to projected climate change This paper presents an overview of the state of the knowledge of possible effect of the climate variability and change on food grain production in India

Water resources and climate change: An Indian perspective

Abstract: In recent times, several studies around the globe show that climatic change is likely to impact significantly upon freshwater resources availability. In India, d emand for water has already increased manifold over the years due to urbanization, agriculture expansion, in-creasing population, rapid industrialization and eco-nomic development. At present, changes in crop ping pattern and land -use pattern, ove r-exploitation of w ater storage and changes in irrigation and drainage are modifying the hydrological cycle in many climate re-gions and river basins of India. An assessment of the availability of water resources in the co n text of future national requiremen ts and expected impacts of climate change and its variability is critical for relevant n atio-nal and regional long -term development strat egies and sustainable development. This article examines the p o-tential for sustainable development of surface water and groundwater resources within the constraints i m-posed by climate change and future r esearch needs in India. Keywords: Climate change, groundwater recharge, hy-drology, run -off, water resource. T

Liposomal Amphotericin B for the Treatment of Visceral Leishmaniasis

Abstract: During the past decade, liposomal amphotericin B has been used with increasing frequency to treat visceral leishmaniasis (VL). The World Health Organization convened a workshop to review current knowledge and to develop guidelines for liposomal amphotericin B use for VL. In Europe, liposomal amphotericin B is widely used to treat VL. In Africa and Asia, the VL disease burden is high and drug access is poor; liposomal amphotericin B is available only through preferential pricing for nonprofit groups in East Africa. Clinical trials and experience demonstrate high efficacy and low toxicity for liposomal amphotericin B (total dose, 20 mg/kg) in immunocompetent patients with VL. Combination trials in areas with antileishmanial drug resistance, and treatment and secondary prophylaxis trials in VL-human immunodeficiency virus-coinfected patients, are important to safeguard the current armamentarium and to optimize regimens. The public health community should work to broaden access to preferential liposomal amphotericin B pricing by public sector VL treatment programs.

Heavy metal contamination in vegetables grown in wastewater irrigated areas of Varanasi, India.

Abstract: No abstract available.

Nuclear modification of electron spectra and implications for heavy quark energy loss in Au+Au collisions at sNN=200GeV

Abstract: The PHENIX experiment has measured midrapidity ([FORMULA: SEE TEXT]) transverse momentum spectra ([FORMULA: SEE TEXT]) of electrons as a function of centrality in Au+Au collisions at [FORMULA: SEE TEXT]. Contributions from photon conversions and from light hadron decays, mainly Dalitz decays of pi0 and eta mesons, were removed. The resulting nonphotonic electron spectra are primarily due to the semileptonic decays of hadrons carrying heavy quarks. Nuclear modification factors were determined by comparison to nonphotonic electrons in p+p collisions. A significant suppression of electrons at high pT is observed in central Au+Au collisions, indicating substantial energy loss of heavy quarks.

Dense-medium modifications to jet-induced Hadron pair distributions in Au+Au collisions at sNN=200GeV

Abstract: Azimuthal correlations of jet-induced high-p(T) charged hadron pairs are studied at midrapidity in Au+Au collisions at sqrt[s(NN)]=200 GeV. The distribution of jet-associated partner hadrons (1.0

Measurement of high-pT single electrons from heavy-flavor decays in p+p collisions at s=200GeV

Abstract: The momentum distribution of electrons from decays of heavy flavor (charm and bottom) for midrapidity |y|< 0.35 in p+p collisions at s=200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over the transverse momentum range 0.3 < p(T)< 9 GeV/c. Two independent methods have been used to determine the heavy-flavor yields, and the results are in good agreement with each other. A fixed-order-plus-next-to-leading-log perturbative QCD calculation agrees with the data within the theoretical and experimental uncertainties, with the data/theory ratio of 1.71 +/- 0.02(stat)+/- 0.18(sys) for 0.3 < p(T)< 9 GeV/c. The total charm production cross section at this energy has also been deduced to be sigma(cc)=567 +/- 57(stat)+/- 193(sys) mu b.

Evaluation Of Ambient Air Pollution Impact On Carrot Plants At A Sub Urban Site Using Open Top Chambers

Abstract: The present experiment was done to evaluate the impact of ambient air pollution on carrot (Dacus carotavar. Pusa Kesar) plants using open top chambers (OTCs) ventilated with ambient (NFCs) or charcoal filtered air (FCs) at a suburban site of Varanasi, India. Various morphological, physiological and biochemical characteristics of the plants were studied at different growth stages. Air monitoring data clearly showed high concentrations of SO2, NO2and O3in the ambient air of study site. SO2and NO2concentrations were higher during early growth stages of carrot, whereas O3concentration was highest during later growth stages. Filtration of air has caused significant reductions in all the three pollutant concentrations in FCs as compared to NFCs.Plants growing in FCs showed significantly higher photosynthetic rate, stomatal conductance, water use efficiency and variable fluorescence as compared to plants growing in NFCs. Protein content also showed a similar pattern, however, lipid peroxidation, ascorbic acid content and peroxidase activity were higher in plants growing in NFCs as compared to FCs. Shoot length, number of leaves per plant, leaf area and root and shoot weight increased significantly upon filtration of ambient air. Total nitrogen decreased significantly in root, but increased significantly in shoot of plants grown in NFCs. Total P, Mg, Ca and K contents decreased significantly in plants grown in NFCs as compared to FCs. The individual pollutant concentrations were below threshold for plant injury, but the combined effect of all the three seems to act synergistically in causing greater adverse impact on dry weight and physiology of carrot plants. The study clearly indicates that air pollutants are high enough in the ambient air to cause significant unfavorable impact on carrot plants. The work further supports the usefulness of OTCs for assessing air pollution damage under field conditions in developing countries.

Suppression of charge order, disappearance of antiferromagnetism, and emergence of ferromagnetism in Nd 0.5 Ca 0.5 MnO 3 nanoparticles

Abstract: Nd0.5Ca0.5MnO3 nanoparticles (average diameter similar to 20 and 40 nm) are synthesized by the polymeric precursor sol-gel method and characterized by various physico-chemical techniques. Quite strikingly, in the 20 nm particles, the charge-ordered (CO) and the antiferromagnetic phases observed in the bulk below 250 K and 160 K, respectively, are completely absent. Instead, a ferromagnetic (FM) transition is observed at 95 K followed by an insulator-to-metal transition at 75 K. The 40 nm particles show a residual CO phase but a transition to the FM state also occurs, at a slightly higher temperature of 110 K.

Powder neutron diffraction study of phase transitions in and a phase diagram of (1-x)[Pb(Mg1/3Nb2/3)O3]-xPbTiO3

Abstract: Dielectric, piezoelectric resonance frequency, and powder neutron diffraction studies as a function of temperature have been performed on several compositions of $(1\ensuremath{-}x)[\mathrm{Pb}({\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}){\mathrm{O}}_{3}]\text{\ensuremath{-}}x\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ $(PM\mathrm{N}\text{\ensuremath{-}}x\mathrm{PT})$ ceramics in and outside the morphotropic phase boundary (MPB) region to investigate the phase transitions and phase stabilities in this mixed system. Anomalies in the temperature dependence of piezoelectric resonance frequency and dielectric constant are correlated with structural changes using Rietveld analysis of powder neutron diffraction data. The frequency dependent dielectric studies reveal relaxor ferroelectric behavior for $xl0.35$ and a normal ferroelectric behavior for $x\ensuremath{\geqslant}0.35$. The dielectric peak temperature and the Vogel-Fulcher freezing temperature are found to increase linearly with ``$x$'' while their difference, after decreasing linearly with $x$, vanishes at $x=0.35$ suggesting a crossover form relaxor ferroelectric to normal ferroelectric behavior at this composition. A phase diagram of the $\mathrm{PMN}\text{\ensuremath{-}}x\mathrm{PT}$ system showing the stability fields of ergodic relaxor, monoclinic ${M}_{B}$, monoclinic ${M}_{C}$, tetragonal and cubic phases is presented. Our results suggest the presence of a succession of three phase transitions, not reported earlier, corresponding to structural changes from the monoclinic ${M}_{B}$ to the monoclinic ${M}_{C}$ to the tetragonal to the cubic phases for $0.27\ensuremath{\leqslant}x\ensuremath{\leqslant}0.30$ on heating above room temperature. In addition, our studies confirm the earlier findings on transitions from the monoclinic ${M}_{C}$ to the tetragonal to the cubic phases for $0.31\ensuremath{\leqslant}x\ensuremath{\leqslant}0.34$ on heating above room temperature and tetragonal to monoclinic ${M}_{C}$ phase on cooling below room temperature for $x=0.36$. All these transitions are found to be accompanied with anomalies either in the temperature dependence of dielectric constant or the piezoelectric resonance frequency or both. Rietveld analyses of the powder neutron diffraction data at various temperatures on a pseudorhombohedral composition with $x=0.25$ suggest that the short range ${M}_{B}$ type monoclinic order present at room temperature grows to long range monoclinic order on lowering the temperature. The temperature variations of the unit cell parameters and atomic shifts are also presented to throw light on the nature of the various phase transitions in this mixed system.

Corrosion of alloys used in dentistry: A review

Abstract: For regaining the normal functions of the dentition, artificial materials are often used to restore the missing part or structure, these are known as dental materials. Metals and alloys, e.g., gold alloys are commonly used dental materials, due to their high strength and other desirable properties. Due to high cost of gold, alloys are being increasingly used in dental applications. Many substitutes for gold alloys have also been employed and some of them possess superior mechanical properties. Increasing knowledge about interaction of dental materials with oral tissues has resulted in evolution of high performance dental materials to meet the various requirements of the oral environment. Leaching of metallic ions and food habits are the main cause of corrosion of metallic dental implants and restorations. Therefore, corrosion has been considered as the most important factor in the selection of metallic materials, hence it deserves special emphasis and must be evaluated in ever-changing oral environment. The main objective of the present review is to describe the importance of corrosion of dental metals and alloys. Different dental materials together with oral environments and various types of corrosion have been described and related reported findings have also been reviewed briefly.

Human sat III and Drosophila hsrω transcripts: a common paradigm for regulation of nuclear RNA processing in stressed cells

Abstract: Exposure of cells to stressful conditions elicits a highly conserved defense mechanism termed the heat shock response, resulting in the production of specialized proteins which protect the cells against the deleterious effects of stress. The heat shock response involves not only a widespread inhibition of the ongoing transcription and activation of heat shock genes, but also important changes in post-transcriptional processing. In particular, a blockade in splicing and other post-transcriptional processing has been described following stress in different organisms, together with an altered spatial distribution of the proteins involved in these activities. However, the specific mechanisms that regulate these activities under conditions of stress are little understood. Non-coding RNA molecules are increasingly known to be involved in the regulation of various activities in the cell, ranging from chromatin structure to splicing and RNA degradation. In this review, we consider two non-coding RNAs, the hsrω transcripts in Drosophila and the sat III transcripts in human cells, that seem to be involved in the dynamics of RNA-processing factors in normal and/or stressed cells, and thus provide new paradigms for understanding transcriptional and post-transcriptional regulations in normal and stressed cells.

Pr3+ doped lithium tellurite glass as a temperature sensor

Abstract: Optical properties of Pr3+ doped lithium tellurite glass suitable for drawing fiber have been studied and profile of energy levels obtained. An excitation with 457.9 nm line of Ar+ gives strong fluorescence from 3P0,1 and 1D2 levels to various low-lying levels. It is found that the fluorescence intensity ratio from 3P1 and 3P0 levels to a common lower level viz. 3H5 at different temperatures can be used to measure the temperature.

Oral miltefosine for the treatment of Indian visceral leishmaniasis.

Abstract: Summary Large-scale antimony resistance in the treatment of visceral leishmaniasis (VL) in north Bihar, India, has led to the development of miltefosine as an alternative therapy. In a pilot study and later in three Phase II studies involving 249 patients, oral miltefosine, 100–150 mg/day for 28 days, was shown to cure ∼90% patients with reasonable safety. In the pivotal Phase III trial, 299 patients were treated at three centres with amphotericin B as the comparator drug (99 patients). In this trial 38% and 20% patients had mild to moderate vomiting and diarrhoea respectively, similar to previous studies. Asymptomatic transient elevation of hepatic transaminases and mild renal dysfunction were observed in 15% and 10% patients respectively. The final cure rate was 94% with miltefosine and 97% with amphotericin B; based on these results, the drug was approved in India. Subsequently in two paediatric studies involving 119 patients in the age group of 2–11 years, the safety and efficacy of miltefosine (2.5 mg/kg daily for 28 days) was established with a cure rate (94%) similar to that seen in adults. Miltefosine is the first oral antileishmanial drug with a high degree of safety and efficacy for the treatment of VL.

J/ψ production and nuclear effects for d+Au and p+p collisions at sNN=200GeV

Abstract: J/{psi} production in d+Au and p+p collisions at {radical}(s{sub NN})=200 GeV has been measured by the PHENIX experiment at rapidities -2.2

Production of L-asparaginase, an anticancer agent, from Aspergillus niger using agricultural waste in solid state fermentation.

Abstract: This article reports the production of high levels of L-asparaginase from a new isolate of Aspergillus niger in solid state fermentation (SSF) using agro-wastes from three leguminous crops (bran of Cajanus cajan, Phaseolus mungo, and Glycine max). When used as the sole source for growth in SSF, bran of G. max showed maximum enzyme production followed by that of P. mungo and C. cajan. A 96-h fermentation time under aerobic condition with moisture content of 70%, 30 min of cooking time and 1205-1405 micro range of particle size in SSF appeared optimal for enzyme production. Enzyme yield was maximum (40.9 +/- 3.35 U/g of dry substrate) at pH 6.5 and temperature 30 +/- 2 degrees C. The optimum temperature and pH for enzyme activity were 40 degrees C and 6.5, respectively. The study suggests that choosing an appropriate substrate when coupled with process level optimization improves enzyme production markedly. Developing an asparaginase production process based on bran of G. max as a substrate in SSF is economically attractive as it is a cheap and readily available raw material in agriculture-based countries.

Common Suppression Pattern of η and π0 Mesons at High Transverse Momentum in Au + Au Collisions at √sNN = 200GeV

Abstract: Inclusive transverse momentum spectra of eta mesons have been measured within p(T)=2-10 GeV/c at midrapidity by the PHENIX experiment in Au+Au collisions at root s(NN) = 200 GeV. In central Au+Au the eta yields are significantly suppressed compared to peripheral Au+Au, d+Au, and p+p yields scaled by the corresponding number of nucleon-nucleon collisions. The magnitude, centrality, and p(T) dependence of the suppression is common, within errors, for eta and pi(0). The ratio of eta to pi(0) spectra at high p(T) amounts to 0.40 < R-eta/pi(0)< 0.48 for the three systems, in agreement with the world average measured in hadronic and nuclear reactions and, at large scaled momentum, in e(+)e(-) collisions.

Effect of oxygen content of powder on microstructure and mechanical properties of hot isostatically pressed superalloy Inconel 718

Abstract: Inert gas atomized (IGA) superalloy Inconel 718 powders with varied oxygen levels of 275, 180 and 140 ppm were consolidated by hot isostatic pressing (HIPing) at 1200 °C/120 MPa/3 h. The microstructural characterization of as-HIPed alloys has shown that the densification phenomenon of the powder does not depend on its oxygen content. However, the formation of deleterious phases such as prior particle boundaries (PPBs) occur more predominantly in the HIPed material produced from the powder with high oxygen content. It was also observed that the recrystallization and formation of annealing twins in the HIPed alloy are greatly influenced by the oxygen content. Transmission electron microscopy (TEM) studies have revealed that the precipitation of γ″, γ′ and δ phases does not depend on oxygen level of HIPed alloy during heat treatment as per AMS 5662J standard schedule but the MC carbides enriched with Nb and Ti precipitated preferentially at the PPBs for the alloy with high oxygen content of 275 ppm. In contrast, the carbides were found to be precipitated more uniformly in the matrix of the alloy with low oxygen content of 140 ppm. Tensile properties of the as-HIPed and HIP + heat treated alloys have shown that the yield strength (YS), ultimate tensile strength (UTS) do not get influenced by the oxygen content, but the ductility was found to be deteriorated drastically at elevated temperatures with increasing the oxygen content of the alloy. Stress rupture properties of the heat treated alloys at 650 °C under a stress level of 690 MPa have maintained a direct relation with the oxygen content, as the alloy with 275 ppm of oxygen content has shown inferior rupture life of 27 h with 2.1% ductility as compared to 84.5 h of life with 4.5% ductility and 116 h of life with 6% ductility offered by the alloys with 180 and 140 ppm of oxygen content, respectively. A better combination of mechanical properties achieved by use of prealloyed powder with low oxygen content makes it possible to explore the near net shape advantage of HIP technology to its maximum potential for alloy 718 components.

Experiments on ecological restoration of coal mine spoil using native trees in a dry tropical environment, India: a synthesis.

Abstract: A series of experiments was conducted on the rehabilitation of mine spoil in a dry tropical region of India for determining the suitability of tree species for plantation, growth performance of selected indigenous species in monoculture and impact of the plantations on the restoration of biological fertility of soil. All of the 17 indigenous species examined could grow in the mine spoil and the growth of a majority of them could be improved by amending the mine spoil with NPK fertilizer. Direct seeding showed greatest height of Zizyphus jujuba and Pongamia pinnata on flat surface, and of Azadirachta indica on slope. In terms of diameter, Syzygium cumini performed best on flat surface and Terminalia arjuna on slope. Total biomass in plantations of selected native tree species on mine spoil at 5-yr age varied from 7.2 to 74.7 t ha−1, being minimum for Shorea robusta and maximum for Dendrocalamus strictus. Total net production ranged from 3.5 (for Shorea robusta) to 32.0 t ha−1 yr−1 (for Dendrocalamus strictus), respectively. Microbial biomass in the redeveloping soil was lower compared to that in natural forest soil but immobilization of soil C in microbial biomass was greater in the mine spoil than in the natural forest. The study indicated that net primary production of the plantations was a function of the amount of foliage, soil C was a function of the amount of litter fall and biomass C was a function of soil C. Plantation of trees significantly accelerated the soil redevelopment process on the mine spoil.

Influence of modified processing on structure and properties of hot isostatically pressed superalloy Inconel 718

Abstract: Inert gas atomized (IGA) superalloy Inconel 718 powder was consolidated by hot isostatic pressing (HIPing) at 1200 °C under 120 MPa pressure for 3 h. The HIPed alloy heat treated as per the aerospace materials specification (AMS) 5662J standard schedule, viz. solution treatment (ST) at 980 °C for 1 h/water quenching (WQ) to room temperature (RT) and a two-step ageing treatment (AT) at 720 °C for 8 h/furnace cooling (FC) at 55 °C h −1 to 620 °C and holding at 620 °C for 8 h and air cooling (AC) to room temperature has exhibited the yield strength (YS) and ultimate tensile strength (UTS) comparable to that of the conventionally processed (forged and heat treated) IN 718. However, its ductility and stress rupture properties at 650 °C were found to be poor due to the presence of prior particle boundary (PPB) networks decorated with highly stable oxides (Al 2 O 3 and TiO 2 ) and brittle MC (Nb, Ti)C carbides. To mitigate this problem, the HIPed alloy was subjected to solution treatment at 1270 °C for 1 h followed by re-HIPing at 1100 °C/130 MPa/3 h before heat-treating it as per AMS 5662J standard schedule. Optical and scanning electron microscopy (SEM) of the alloy processed under modified HIPing and heat treatment conditions have shown the dissolution of MC-carbides, breaking up of PPB networks and formation of equiaxed grains with an average diameter of about 50 μm. Transmission electron microscopy (TEM) of this alloy has revealed uniform distribution of γ″ and γ′ strengthening precipitates in the γ-matrix and the presence of δ(Ni 3 Nb) phase as well as very fine oxide particles near the grain boundaries. The tensile properties of the alloy processed under modified conditions have shown quite satisfactory levels of YS and UTS combined with a significantly improved elongation (EL) values at room temperature (19.5%) and at 650 °C (8.0%). The improvement in alloy ductility was found to correlate well with the fractography of the tensile tested specimens, which showed the predominance of transgranular fracture with fine dimples at room temperature and fine dimples together with the particle boundary facets at 650 °C. The stress rupture properties of modified processed alloy at 650 °C and at a stress level of 690 MPa have shown a vastly improved rupture life of 80 h combined with 5% ductility. The improvement in tensile and stress rupture properties accomplished by the modified processing makes it possible to explore the near net shape capability of HIP technology to its full potential in the development of alloy 718 components.