9 resultados para pollen concentration in the air
em Cochin University of Science
Resumo:
The present study is an attempt to find out the ralation between RNA/DNA ratio, protein,percentage growth rate and specific growth rate of prawn,Penaeus indicus with respect to Nervous system, Eyestalk and Muscle tissues during ontogenesis. We have isolated and purified a natural agglutinin in the hemolymph of P.indicus with antigenecity, agglutinating, hemolytic and antibacterial properties. The influence of growth and environmental parameters on the level of agglutinin in the hemolymph was studied. Agglutinin concentration during normal growth process was compared. The agglutinin concentration in the hemolymph was quantified through developing ELISA, which is useful in health monitoring studies of individual species. Complete amino acid composition of both the subunits of P.indicus agglutinin were analysed. P.indicus agglutinin showed similarity to those proteins having antigenecity,hemolytic and agglutinating properties.Hence, agglutinin was considered as a natural defence protein in the hemolymph of P.indicus responsible for immune surveillance. The humoral defence mechanism of agglutinin was a co-operative effort with hemocytes and complement system. The composition of isolated agglutinin of P.indicus amino acids will be helpful in the synthesis of new antibacterial analogues which can be used against disease causing organisms.
Resumo:
This thesis Entitled Trace metal speciation in the cochin estuary.Natural waters provide a favourable environment for speciation studies because of the prevailing variable chemical matrix and the variety of metal forms which may exist there.An estuary is a mixing zone of riverine and oceanic waters with widely varying compositions where end members interact both physically and chemically. The trace element chemistry in the estuarine environment has been an area of considerable research in the past decades. The trace metal distribution in the Cochin estuary is considerably influenced by the tropical features of the location and by human activities. The lower Periyar river and the Cochin estuary have been particularly selected for this investigation in view of the impact of trace metals on the estuarine ecosystem as well as in attempt quantify the phenomenon of metal speciation in the waters of a tropical coastal plain waterbody. If the concentration in the water media is very low, then, many of the fractions that could be estimated by speciation schemes for metals will fall below the detection limits, a factor which is undesirable.The study would also delineate the features of metal speciation which modify the chemical regime of ionic elements that traverse natural boundaries in aquatic environments, especally in those tropical areas prone to multivariate geographical settings.
Resumo:
Prevalence of faecal coliform bacteria and the survival of Escherichia coli, Vibrio parahaemolyticus and Salmonella paratyphi were studied in the water and sediment from Vembanadu Lake in the presence and absence of protozoan predators. The density of faecal coliform bacteria ranged between mean MPN value 5080–9000/100 ml in water and 110,000–988,000/1 g in sediment (p <0.01), which was 110 times greater than in overlying water. The laboratory microcosm studies revealed that E. coli, V. parahaemolyticus and S. paratyphi showed significantly higher survival (p <0.05) potential in sediment than in overlying water both in the presence and absence of protozoan predators. The results indicate that Vembanadu Lake sediment constitutes a reservoir of pathogenic bacteria and exhibits potential health hazard from possible resuspension and subsequent ingestion during recreational activities. Therefore, assessment of bacterial concentration in freshwater lake sediments used for contact and non-contact recreation is of considerable significance for the proper assessment of microbial pollution of the overlying water and the management and protection of related health risk at specific recreational sites. In addition, assessment of the bacterial concentration in sediments can be used as a relatively stable indicator of long-term mean bacterial concentration in the water column above.
Resumo:
A series of vanadium-niobium oxide catalysts in which the vanadia content varies between 0.3 and 18mol%was prepared by coprecipitation. These catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), low-energy ion scattering (LEIS), and by catalytic testing in the oxidative dehydrogenation reaction of propane. The results of the surface analysis by XPS and LEIS are compared. It is concluded that the active site on the catalyst surface contains 2.0 ± 0.3 vanadium atoms on average. This can be understood byassuming the existenceof two or three different sites:isolated vanadium atoms, pairs of vanadium atoms, or ensembles of three vanadium atoms. At higher vanadium concentration more vanadium clusters with a higher activity are at the surface.LEIS revealed that as the vanadium concentration in the catalyst increases, vanadium replaces niobium at the surface. At vanadium concentrations above 8 mol%, new phases such as P-(Nb, V)20S which are less active because vanadium is present in isolated sites are formed, while the vanadium surface concentration shows a slight decrease
Resumo:
This paper discusses the salient features associated with the variation in the BODs and dissolved oxygen concentration in the Kadinamkulam Kayal based on fortnightly data from two selected stations from October1987toSeptember1988.The BODs ranged from 5.76 to 24.39 mg/l in the surface water and from 4.96 to 22.60mg!1 in the bottom waterat station-l whereas at station-2, it ranged from 0 to 3.74mg/1 in the surface water and from 0 to 3.40 mg!l in the bottom water. The dissolved oxygen concentration ranged from 0 to 0.72 mglI in the surface water and from 0 to 0.42 mg!l in the bottom waterat station-I, At station-2 it ranged from 2.69 to 6.21mg!1 in the surface waterand from 1.97 to 5.74 mg!1 in the bottom water. The pre-monsoom period showed the highest BODsof 16.68mg!I while the monsoon period showed the lowest of 0.61 mg!I. The dissolved oxygen concentration reached its peak during the monsoon period (5.52 mg/I). Long spells of anoxic condition during the post and pre-monsoon periods was a characteristic feature of the retting zone
Resumo:
Heavy metals in the surface sediments of the two coastal ecosystems of Cochin, southwest India were assessed. The study intends to evaluate the degree of anthropogenic influence on heavy metal concentration in the sediments of the mangrove and adjacent estuarine stations using enrichment factor and geoaccumulation index. The inverse relationship of Cd and Zn with texture in the mangrove sediments suggested the anthropogenic enrichment of these metals in the mangrove systems. In the estuarine sediments, the absence of any significant correlation of the heavy metals with other sedimentary parameters and their strong interdependence revealed the possibility that the input is not through the natural weathering processes. The analysis of enrichment factor indicated a minor enrichment for Pb and Zn in mangrove sediments. While, extremely severe enrichment for Cd, moderate enrichment for Zn and minor enrichment of Pb were observed in estuarine system. The geo accumulation index exhibited very low values for all metals except Zn, indicating the sediments of the mangrove ecosystem are unpolluted to moderately polluted by anthropogenic activities. However, very strongly polluted condition for Cd and a moderately polluted condition for Zn were evident in estuarine sediments
Resumo:
The study is undertaken with an objective to investigate the linkage between air-sea fluxes in the Indian Ocean and monsoon forcing. Since the monsoon activity is linked to fluxes, the variability of surface marine meteorological fields under the variable monsoon conditions is also studied. The very objective of the present study is to document various sea surface parameters of the Indian Ocean and to examine the anomalies found in them. Hence it is attempted to relate the anomaly to the variability of monsoon over India, highlighting the occasion of contrasting monsoon periods. The analysis of anomalies of surface meteorological fields such as SST, wind speed and direction, sea level pressure and cloud cover for contrasting monsoons are also studied. During good monsoon years, the pressure anomalies are negative indicating a fall in SLP during pre-monsoon and monsoon months. The interaction of the marine atmosphere with tropical Indian Ocean and its influence on ISMR continue to be an area of active research.
Resumo:
ZnS: Cu: Cl phosphor prepared under a vacuum firing process is found to give blue electroluminescence with emission peak at 460 nm which remams unaltered with the frequency of the excitation voltage. Addition of excess chlorine in the phosphor gives blue, green and red emission at 460, 520 and 640 run. The intensity of the blue band decreases and It fmally disappears as chlorine concentration is increased. A scheme involving three energy levels attributed to Cu2+, Cu+ and Cl- centres in Zns explains the experimental results completely.
Resumo:
Mangroves are considered to play a significant role in global carbon cycling. Themangrove forests would fix CO2 by photosynthesis into mangrove lumber and thus decrease the possibility of a catastrophic series of events - global warming by atmospheric CO2, melting of the polar ice caps, and inundation of the great coastal cities of the world. The leaf litter and roots are the main contributors to mangrove sediments, though algal production and allochthonous detritus can also be trapped (Kristensen et al, 2008) by mangroves due to their high organic matter content and reducing nature are excellent metal retainers. Environmental pollution due to metals is of major concern. This is due to the basic fact that metals are not biodegradable or perishable the way most organic pollutants are. While most organic toxicants can be destroyed by combustion and converted into compounds such as C0, C02, SOX, NOX, metals can't be destroyed. At the most the valance and physical form of metals may change. Concentration of metals present naturally in air, water and soil is very low. Metals released into the environment through anthropogenic activities such as burning of fossils fuels, discharge of industrial effluents, mining, dumping of sewage etc leads to the development of higher than tolerable or toxic levels of metals in the environment leading to metal pollution. Of course, a large number of heavy metals such as Fe, Mn, Cu, Ni, Zn, Co, Cr, Mo, and V are essential to plants and animals and deficiency of these metals may lead to diseases, but at higher levels, it would lead to metal toxicity. Almost all industrial processes and urban activities involve release of at least trace quantities of half a dozen metals in different forms. Heavy metal pollution in the environment can remain dormant for a long time and surface with a vengeance. Once an area gets toxified with metals, it is almost impossible to detoxify it. The symptoms of metal toxicity are often quite similar to the symptoms of other common diseases such as respiratory problems, digestive disorders, skin diseases, hypertension, diabetes, jaundice etc making it all the more difficult to diagnose metal poisoning. For example the Minamata disease caused by mercury pollution in addition to affecting the nervous system can disturb liver function and cause diabetes and hypertension. The damage caused by heavy metals does not end up with the affected person. The harmful effects can be transferred to the person's progenies. Ironically heavy metal pollution is a direct offshoot of our increasing ability to mass produce metals and use them in all spheres of existence. Along with conventional physico- chemical methods, biosystem approachment is also being constantly used for combating metal pollution