Variational method for objective analysis of scalar variable and its derivative

In this study real time data have been used to compare the standard and triangle method by performing the objective analysis of mean sea level pressure. In the standard method, derivative fields are obtained from the grid point data using finite difference scheme whereas in the triangle method, a set of non-overlapping triangles are formed from the observations and the scalar and the spatial derivatives are computed directly at the centroid of each of the non-overlapping triangles. These scalars and their derivatives are then mapped to uniform grids by using the standard method. It has been found that objectively analysed scalar field obtained using standard method is superior to the scalar field derived by the triangle method, whereas the derivative fields produced by triangle method are superior to the derivative fields produced using standard method. A variational objective analysis scheme has been developed and an experiment has been carried out with depression case of June (11-15) 2004. It is found that the new scheme (variational) is able to extract the better parts of both triangle and standard methods. The results of this study will be useful in carrying out diagnostic calculations that involve derivative estimates

GENOPROTECTIVE EFFECTS OF ETHANOLIC STEM EXTRACTS OF TINOSPORA CORDIFOLIA ON SODIUM ARSENITE-INDUCED DNA DAMAGE IN SWISS MICE LYMPHOCYTES BY COMET ASSAY

Objective: The study was aimed to evaluate the DNA protective effects of ethanolic extracts of Tinospora cordifolia stem on Swiss albino mice lymphocytes against the sodium arsenite-induced genotoxicity. Methods: In this experiment, 25 animals of nearly the same age were equally divided. Group 1 (control) fed on tap water while rest four (2, 3, 4, and 5) groups were treated with 4 mg/kg body weight, per orally sodium arsenite for 12 weeks. Sodium arsenite pretreated groups (4 and 5) were followed by administration of 80 mg/kg body weight, per orally T. cordifolia extracts for the next 12 weeks. Animals were sacrificed at the 8th week and 12th week, respectively, for the assessment of sodium arsenite-induced genotoxicity and comparative genoprotective effects of experimental plant extracts. The extent of DNA migration is directly proportional to the magnitude of DNA damage. Percentage tail DNA content and olive tail moment parameters were used in the comet to relate DNA damage. Results: The findings suggested that the ethanolic stem extracts of T. cordifolia significantly inhibited the sodium arsenite-induced oxidative genotoxicity. The phytoconstituents of T. cordifolia shown to retard genetic damage associated with arsenic exposure. Conclusion: T. cordifolia may be used as a preventive herbal preparation against chemical or arsenical toxicity

Mesoscale objective analysis of daily rainfall with satellite and conventional data over Indian summer monsoon region

A mesoscale objective analysis scheme for producing daily rainfall analysis on a regular latitude/longitude grid over the Indian monsoon region is described. The Barnes scheme is applied to interpolate irregularly distributed daily rainfall data on to a regular grid. The spatial resolution of the interpolated arrays is 0.25 degrees of latitude by 0.25 degrees of longitude. Daily rainfall derived from INSAT IR radiances and raingauge observations are combined to produce this analysis. Some objectively determined constraints are employed in this study: (i) weights are determined as a function of data spacing, (ii) in order to achieve convergence of the analysed values three passes through the data are considered and there is automatic elimination of wavelengths smaller than twice the average data spacing. The case of a typical westward moving monsoon depression during the 1994 monsoon season is selected to represent the characteristics of the analysed rainfall. Objective analyses of six days (16 to 21 August 1994) have been carried out using Barnes three pass scheme. The weighting function scale length parameter (c, denominator in the exponential Gaussian weight function) is varied from over a range of values and the root mean square (rms) errors are computed to select the appropriate value of c. The value of c depends on the number of correction passes being performed and on the density of the observations. The characteristics of the output field from this analysis system have been examined by comparing the analysed rainfall with the observed values. The heavy rainfall over the Western Ghat of India has been clearly brought out in this analysis

An efficient optimum interpolation scheme for objective analysis over Indian region

In the optimum interpolation scheme, the weights for the observations are computed by solving a set of linear equations for every grid point. As the number of observations increases particularly over data-rich regions, the matrix dimension increases and the computer time required to solve these equations to determine weights increases considerably. In order to reduce the computer time for computing the weights, Tanguay and Robert suggested schemes in which the gaussian function representing the autocorrelation function has been approximated by a second-order and also by a fourth-order Taylor series expansion. This resulted in the solution of matrices of order 4 or 9 respectively to obtain weighting functions irrespective of the number of observations used in the analysis. In the present study, the analyses of mean sea level pressure and geopotential height at 700 mbar level have been carried out for five days using the above two schemes and the regular OI scheme. The analyses are found to be similar in all the three cases suggesting that a lot of computer time could be saved without sacrificing the analysis accuracy by using the modified scheme in which the second-order approximation is utilized

Rainfall analysis using conventional and non-conventional rainfall information on monthly scale

The aim of this paper is to describe the technique used to create the merged analysis of rainfall over the Indian and adjoining region (1.5° to 35.5° N and 63.5° to 97.5° E). The technique is tested for monthly gridded fields of rainfall for a 2–year monsoon period (2001 and 2003) on a 1° x 1° latitude–longitude grid by merging rainfall estimates from different sources, viz satellite based estimates, rain gauge analysis and numerical weather prediction model rainfall. First, in order to reduce the random error involved in the satellite rainfall estimates and the model predictions, satellite and model estimates are combined linearly based on a maximum likelihood estimate method. In this case the weight for each component is inversely proportional to the squares of the individual random errors. The weight is determined by comparing the components with the concurrent gauge analysis. As the combined analysis contains bias from the individual input data sources, the combined analysis is then blended with the analysis based on gauge observations. It is seen that the merged analysis produced here is closer to the observations than the individual sources. It is observed that the magnitude and distribution of the orographic heavy rainfall along the Western Ghats of India is very different and more realistic compared to the Global Precipitation Climatology Project (GPCP) and the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP). When compared with the India Meteorological Department analysis, it is found that the merged analysis shows higher correlation than the satellite and model predicted rainfall. From the results it can be concluded that this study has shown promising results and the analyses can be used as a bench mark for evaluating model simulations which serves as a basis for real–time monitoring. Based on these promising results, long term datasets on high resolution grid for daily and monthly scale over Indian and adjoining region will be generated, which in turn can be used to study spatial and temporal variability of rainfall over Indian and adjoining regio

EVALUATION OF ANTICLASTOGENIC POTENTIAL OF CINNAMOMUM CASSIA BARK EXTRACT AGAINST ARSENIC GENOTOXICITY BY USING MICRONUCLEUS ASSAY IN MUS MUSCULUS CAUDAL ERYTHROCYTES

Objective: The study was aimed to evaluate the anticlastogenic potential of ethanolic extract of Cinnamomum cassia against arsenic-induced genotoxicity.Methods: In the experiment, 30 animals were taken and divided into five groups and each group contains six animals. Group 1 was control and fed on tap water of Patna city while rest four (2, 3, 4, 5) groups were treated with 4 mg/kg body weight, per orally sodium arsenite for 8 weeks. Sodium arsenite pre-treated Groups 4 and 5 were followed by dose of 100 mg/kg body weight of 5% ethanolic solution of test plant bark extract for next 8 weeks (total duration of dosing 16 weeks). Caudal blood collected from each mouse by minor nick without their sacrifice and smeared blood was stained by double staining. Approximately, 2000 cells were scored by light microscopy to determine micronucleus (MN) frequency. The percentage of MN frequency was expressed in the terms of mean and standard deviation.Results: High index of MN frequency was observed in the Groups 2 and 3 while its frequency drastically reduced in Groups 4 and 5. The mean number of MN scored per 2000 cell were found to be 4.5, 23.5, 18.8, 10.5, and 9.66 in animal Groups 1, 2, 3, 4, 5,respectively.Conclusion: C. cassia may be effective drug in the area of preventive cancer or other kinds of diseases which lead to damage of genetic materials

Dendroclimatic analysis of teak (Tectona grandis L. f.) annual rings from two locations of peninsular India

Climate-related tree-growth variability in teak (Tectona grandis L. f.) has been studied based on response function analysis from dry deciduous forests of Mundagod (Karnataka) and Chandrapur (Maharashtra), peninsular India, representing two ecological zones. Rainfall during the monsoon months of the current year was found to be positively associated with radial growth of teak at both sites, whereas premonsoon April rainfall was found to be negatively associated. Rainfall and temperature of the current year during March have positive influence on the growth of teak at Chandrapur and Mundagod respectively. Furthermore, rainfall during October of the preceding year showed negative influence on tree growth at Mundagod and positive influence at Chandrapur, which might be due to the difference in relative humidity and soil type at both the locations, apart from soil moisture

Effect of growth rate and latewood content on basic density of wood from 120-to 154-Year-old natural-grown Teak (Tectona grandis L. f.)

The relationship between the radial variations of growth ring features and basic density were investigated in juvenile and mature wood for five 120-to150-year-old trees of Tectona grandis L. grown naturally in moist deciduous forest of Thane,Maharashtra. The study showed that the mean basic density of growth rings in juvenile wood was 0.665 (0.602-0.702) g cm-3 and 0.613 (0.562-0.665) g cm-3 in mature wood. The annual growth in juvenile period was high with a ring width mean of 4.03 mm and the latewood content represented 76.36 % of the annual growth, while in mature period was low with a ring width mean of 1.24 mm and the latewood content represented 59.41% of the annual growth. The patterns of radial variation of ring width, latewood content and basic density were more inherent in the juvenile wood than mature wood of all trees due to cambial ageing. The basic density of five individual trees showed an insignificant correlation between ring-width and latewood content in juvenile wood, whereas a significant positive correlation was found in mature wood of most of individual trees. The mean ring width value of all trees showed a highly significant positive correlation with basic density in both types of wood but mean latewood content showed a non-significant or low significant correlatio

Rhizosphere of rice plants harbor bacteria with multiple plant growth promoting features

114 diazotrophic bacteria from the rice rhizosphere of five districts of Eastern Uttar Pradesh (India) were isolated and screened for plant growth promoting (PGP) activities employing standard microbiological and biochemical techniques. All these isolates showed nitrogenase activity in the range of 0.23 to 1.72 μmol C2H4 mg-1 protein h-1. Further analysis showed that 84 (73.68%) isolates were Indole-3-acetic acid (IAA) producer; the value of IAA production ranged from 10.1 to 353.0 μg IAA mg-1 protein. IAA production occurred solely in the medium supplemented with tryptophan. P solubilization activity was observed in 28 (24.56%) isolates, the activity being in the range of 38.50 to 321.0 P released μg mg-1 protein. 45 (39.46%) isolates were capable of producing siderophore, the range of production being 4.50 to 223.26 μg mg-1 protein. Analysis of molecular diversity was made by amplified ribosomal DNA restriction analysis (ARDRA) and denaturating gradient gel electrophoresis (DGGE), which exhibited distinct differences among all the isolates. Of the 114 isolates, twenty one (21) isolates showed multiple plant growth promoting traits and were potent in terms of PGP activities. These isolates were identified on the basis of 16S rDNA sequencing and belonged to the genera Pantoea, Bacillus, Microbacterium, Pseudomonas, Sphingomonas, Ancylobacter, Enterobacter, Advenella, γ-proteobacterium strain VA3S1, Rhizobium and Agrobacterium. Findings of this study suggest that certain isolates may be exploited for developing a potential source of biofertilizer.Key words: Plant growth promoting rhizobacteria, N2 fixation, amplified ribosomal DNA restriction analysis, indole-3-acetic acid, siderophore, denaturing gradient gel electrophoresis, temperature gradient gel electrophoresi