Retrieval of sea surface velocities using sequential Ocean Colour Monitor (OCM) data

The Indian remote sensing satellite, IRS-P4 (Oceansat-I) launched on May 26th, 1999 carried two sensors on board, i.e., the Ocean Colour Monitor (OCM) and the Multi-frequency Scanning Microwave Radiometer (MSMR) dedicated for oceanographic research. Sequential data of IRS-P4 OCM has been analysed over parts of both east and west coast of India and a methodology to retrieve sea surface current velocities has been applied. The method is based on matching suspended sediment dispersion patterns, in sequential two time lapsed images. The pattern matching is performed on a pair of atmospherically corrected and geo-referenced sequential images by Maximum Cross-Correlation (MCC) technique. The MCC technique involves computing matrices of cross-correlation coefficients and identifying correlation peaks. The movement of the pattern can be calculated knowing the displacement of windows required to match patterns in successive images. The technique provides actual flow during a specified period by integrating both tidal and wind influences. The current velocities retrieved were compared with synchronous data collected along the east coast during the GSI cruise ST-133 of R.V. Samudra Kaustubh in January 2000. The current data were measured using the ocean current meter supplied by the Environmental Measurement and CONtrol (EMCON), Kochi available with the Geological Survey of India, Marine Wing. This current meter can measure direction and magnitude with an accuracy of ±5‡ and 2% respectively. The measurement accuracies with coefficient of determination (R2 ) of 0.99, for both magnitude (cm.s-1) and direction (deg.) were achieved

APPLICATIONS OF IMAGING SPECTROSCOPY FOR NON-METALLIC MINERAL EXPLORATION

Imaging spectroscopy/hyperspectral remote sensing technique acquires images in a very narrow and contiguous spectral bands. High spectral resolution data provided by imaging spectrometers enables remote compositional mapping of earth surface. In the present study, we demonstrate the potentials of airborne AVIRIS-NG datasets for identification and mapping of non-metallic minerals. Several minerals such as carbonates, sulphates and phyllosilicate exhibit diagnostic absorption feature in Short Wave Infrared Region (SWIR) (2.0–2.5 μm). Therefore, mapping of wavelength of deepest absorption in SWIR is very useful for exploratory earth surface composition/mineral mapping. To map the mineralogical diversity in the parts of Banswara region, Rajasthan, wavelength of deepest absorption feature and absorption band depth in SWIR region was calculated at each pixel. It was found that majority of pixels showed absorption near ∼2.31, 2.33 and 2.20 μm. Detailed analysis of spectra of image revealed dolomite as dominant mineral at pixels showing deepest absorption at 2.31 μm. Calcite and clays were found to be present at pixels showing deepest absorption feature near 2.33 and 2.20 μm respectively. It is noted that mapping wavelength position of deepest feature is a very fast and reliable indicator of mineralogy. The mineral map of calcite and dolomite shall be useful for locating new mining prospect in the region

Application of IRS-P4 OCM data to study the impact of cyclone on coastal environment of Orissa

The present study emphasizes on the impact of cyclone on the coastal environment of Orissa, using the IRS-P4 (OCM) satellite data. The study includes the analysis of IRS-P4 (OCM) data to generate chlorophyll, Suspended Sediment Concentration (SSC) images for the coastal water and Normalized Difference Vegetation Index (NDVI) images for coastal vegetation in the pre and post-cyclonic stages. The effect on mangroves and change in distribution pattern of water constituents like chlorophyll and suspended sediments are brought out

Elevated Proteasome Capacity Extends Replicative Lifespan in Saccharomyces cerevisiae

Aging is characterized by the accumulation of damaged cellular macromolecules caused by declining repair and elimination pathways. An integral component employed by cells to counter toxic protein aggregates is the conserved ubiquitin/proteasome system (UPS). Previous studies have described an age-dependent decline of proteasomal function and increased longevity correlates with sustained proteasome capacity in centenarians and in naked mole rats, a long-lived rodent. Proof for a direct impact of enhanced proteasome function on longevity, however, is still lacking. To determine the importance of proteasome function in yeast aging, we established a method to modulate UPS capacity by manipulating levels of the UPS–related transcription factor Rpn4. While cells lacking RPN4 exhibit a decreased non-adaptable proteasome pool, loss of UBR2, an ubiquitin ligase that regulates Rpn4 turnover, results in elevated Rpn4 levels, which upregulates UPS components. Increased UPS capacity significantly enhances replicative lifespan (RLS) and resistance to proteotoxic stress, while reduced UPS capacity has opposing consequences. Despite tight transcriptional co-regulation of the UPS and oxidative detoxification systems, the impact of proteasome capacity on lifespan is independent of the latter, since elimination of Yap1, a key regulator of the oxidative stress response, does not affect lifespan extension of cells with higher proteasome capacity. Moreover, since elevated proteasome capacity results in improved clearance of toxic huntingtin fragments in a yeast model for neurodegenerative diseases, we speculate that the observed lifespan extension originates from prolonged elimination of damaged proteins in old mother cells. Epistasis analyses indicate that proteasome-mediated modulation of lifespan is at least partially distinct from dietary restriction, Tor1, and Sir2. These findings demonstrate that UPS capacity determines yeast RLS by a mechanism that is distinct from known longevity pathways and raise the possibility that interventions to promote enhanced proteasome function will have beneficial effects on longevity and age-related disease in humans

Progress on silica pervaporation membranes in solvent dehydration and solvent recovery processes

10.3390/ma13153354Materials1315335

Application of IRS-P4 OCM data to study the impact of tidal propagation on sediment dynamics in the Gulf of Kachchh

This paper reports observations with respect to suspended sediment dispersal pattern at various stages of the tide cycles using the Indian Remote Sensing Satellite (IRS-P4) Ocean Colour Monitor (OCM) data, exploiting the high temporal resolution of two days and specific narrow spectral channels suitable to retrieve suspended sediment concentration. The shelf region of the Gulf, west of its mouth, plays a key role in sediment dispersal pattern within the Gulf of Kachchh as is evidenced by different linear shaped, clockwise and anticlockwise circulation patterns. The suspended sediments are transported as a V-shaped front into the Gulf during flooding conditions and as linear plumes fanning out of the Gulf during ebb conditions. Sediments are being transported into the Gulf along the northern shore from the Indus delta during flooding phase, whereas the southern shore gets sediments from the southern parts of the mouth. The study of sediment dispersal pattern led to dividing the Gulf of Kachchh into six zones, having characteristic sediment dispersal patterns. The information is useful for maintaining the approach channels of ports in addition to understanding dispersal of pollutants such as oil slicks under tidal influence

Application of IRS-P4 OCM data to study the impact of tidal propagation on sediment dynamics in the Gulf of Kachchh

129-137This paper reports observations with respect to suspended sediment dispersal pattern at various stages of the tide cycles using the Indian Remote Sensing Satellite (IRS-P4) Ocean Colour Monitor (OCM) data, exploiting the high temporal resolution of two days and specific narrow spectral channels suitable to retrieve suspended sediment concentration. The shelf region of the Gulf, west of its mouth, plays a key role in sediment dispersal pattern within the Gulf of Kachchh as is evidenced by different linear shaped, clockwise and anticlockwise circulation patterns. The suspended sediments are transported as a V-shaped front into the Gulf during flooding conditions and as linear plumes fanning out of the Gulf during ebb conditions. Sediments are being transported into the Gulf along the northern shore from the Indus delta during flooding phase, whereas the southern shore gets sediments from the southern parts of the mouth. The study of sediment dispersal pattern led to dividing the Gulf of Kachchh into six zones, having characteristic sediment dispersal patterns. The information is useful for maintaining the approach channels of ports in addition to understanding dispersal of pollutants such as oil slicks under tidal influence