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Search Results: 1 - 10 of 554807 matches for " A. K. Patra "
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Biomass and productivity in sal and miscellaneous forests of Satpura plateau (Madhya Pradesh) India  [PDF]
Pramod Kumar Pande, A. K. Patra
Advances in Bioscience and Biotechnology (ABB) , 2010, DOI: 10.4236/abb.2010.11005
Abstract: The paper deals with the biomass and productivity of sal (SF) and miscellaneous forests (MF) of Satpura plateau (Madhya Pradesh) India. These forest types were divided into four sites namely open miscellaneous (OMF, site-I), closed miscellaneous (CMF, site-II), open sal (OSF, site-III) and closed sal (CSF, site-IV). The degree of disturbance followed the order: III (0.70) < I (0.12) < II (0.054) < IV (0.018) while considering total trees as measure. OSF (III) and CSF (IV) were most and least disturbed sites among the four. The percent allocation of above ground tree biomass followed the order: 85.08 (II) < 85.51 (I) < 81.31 (III) < 78.09 (IV). The higher above ground tree biomass was produced by MF than of SF. Closed canopy forests produced higher above ground tree biomass than of the open forests. OMF produced 9.5% less biomass than of the CMF whereas, OSF has 39.91% less biomass than of the CSF. The contribution of above ground biomass of shrubs (%) are as follows: 8.3 (IV)< 32.72 (I) <33.77 (III) <52.63 (II). The percent contribution of root biomass was higher for closed sites as compared with open and sites. The root: shoot ratio was ranged between 0.169-0.249. NPPtree (kg ha-1yr-1) was highest for site –IV (38094.79), followed by III (33384.29), II (12374.89 and I (9736.52). NPPshrub followed the order: 204 (IV) > 109 (III) > 79.80 (I) > 52.69 (II), while for NPPherb, the order of importance was, 109.50 (IV) > 73.27 (I) > (II), 71.75 (III) > 55.71 (II). NPPtotal was highest for closed forest stands than of the open ones. NPPteak was lower for high-disturbed site than of the less disturbed site. Photosynthetic/ non - photosynthetic ratio follows the order: 0.067 (II) > 0.030 (III) > 0.026 (IV) > 0.018 (I). Open forests showed lower values for this ratio. NEP was higher for SF than of the MF. Further closed forests showed higher values of NEP. OSF showed lower values of NEPsal than of the CSF. Disturbances in open forests not only reduced stand biomass of tree species, dominant species in particular, but also declined the tree productivity. So, gap filling plantation in side the forest is suggested to improve the productivity of open forests.
Use of Bio-Resources for Remediation of Soil Pollution  [PDF]
Sharmistha Pal, A. K. Patra, S. K. Reza, Walter Wildi, John Pote
Natural Resources (NR) , 2010, DOI: 10.4236/nr.2010.12012
Abstract: In recent years, economic boom in fast developing countries has been witnessed with spectacular progress in industri- alization and concurrent progress in modern agriculture. Such development is however not without any socio-political and environmental side effects. A major concern has been the environmental pollution. If the current unabated disposal of various forms of wastes to agricultural lands is continued, the inherent capacity of soil to support agricultural pro- duction and sustain other ecosystem services will be in peril. Heavy metals with soil residence times of thousands of years present numerous health hazards to higher organisms. They are also known to decrease plant growth, ground cover and have a negative impact on soil biodiversity. Inorganic and organic contaminants typically found in urban areas are heavy metals and petroleum derived products. The presence of both types of contaminants on the same site presents technical and economic challenges for decontamination strategies. In this article we have reviewed the devel- opments to ameliorate the contaminated soils, with special emphasis on biological approaches, which have shown po- tential to low-cost remediation of soil pollution. Also the limitations of such approaches and direction of further re- search have been highlighted.
Phototrophic Growth and Accumulation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Purple Nonsulfur Bacterium Rhodopseudomonas palustris SP5212
M. Mukhopadhyay,A. Patra,A. K. Paul
Journal of Polymers , 2013, DOI: 10.1155/2013/523941
Abstract: The ability of the phototrophic bacterium Rhodopseudomonas palustris SP5212 to produce polyhydroxyalkanoates (PHAs), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] in particular was, assessed in acetate medium supplemented with hydroxybutyrate and valerate as cosubstrates. The isolate accumulated the polymer accounting for some 49.06% and 30% of cell dry weight when grown in hydroxybutyrate and valerate, respectively. PHA accumulation as well as 3HV monomer incorporation (30?mol%) was maximum at 0.1% hydroxybutyrate, while valerate at 0.1% and 0.3% was suitable for total polymer accumulation and 3HV monomer incorporation, respectively. Cosupplementation of hydroxybutyrate and valerate in the ratio of 3?:?1 led to the accumulation of PHA accounting for 54% of cell dry weight, which contained more than 50?mol% of 3HV monomer. Moreover, the biphasic cultivation conditions with hydroxybutyrate as cosubstrate have improved the quality as well as quantity of the accumulated copolymer significantly. 1. Introduction Polyhydroxyalkanoates (PHAs) represent a unique class of environmentally biodegradable polymers of commercial importance. They are synthesized and accumulated as intracellular carbon and energy rich reserve materials by a wide variety of bacteria when grown under conditions of carbon excess and at least one of the nutrients becomes limiting [1, 2]. PHAs serve as a sink for reducing equivalents depending on the organisms and the physiological conditions of the cells. Accumulated PHAs also play a significant role in the survival of the producer microorganisms under conditions of environmental stress such as osmotic pressure, desiccation, and UV-irradiation [3]. Moreover, they have received increased attention as alternatives to conventional hydrocarbon based thermoplastics mainly because of their material properties, biodegradability, and biocompatibility. The incorporation of 3-hydroxyvalerate (3HV monomer) into the polymer of 3-hydroxybutyrate (3HB) can result in the synthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] with improved thermoplastic properties that are more suitable for commercial application [4]. It is, therefore, apparent that the PHA materials can be tailored to specific applications by varying their chemical structure [5], which could be achieved by variation of producing organisms, carbon sources, cosubstrates and cultural conditions. Altogether, 150 hydroxyalkanoic acids have been identified as constituents of PHAs [6], and these subunits of PHA have been broadly subdivided as short chain length
Intriguing aspects of F-region plasma irregularities revealed by the Gadanki radar observations during the SAFAR campaign
A. K. Patra,D. V. Phanikumar
Annales Geophysicae (ANGEO) , 2009,
Abstract: Intriguing new results of F-region irregularities observed using the Gadanki MST radar during the SAFAR campaigns, which were conducted during the equinox and summer of 2008 that corresponds to low solar activity condition, are presented. The summer observations are first of its kind from Gadanki. Observations revealed remarkably different morphology of the F-region irregularities in summer when compared to that in equinox. In summer, the F-region irregularities were observed as horizontally stratified structures, while in equinox they were observed as plume structures. Further, the irregularities in summer commenced during the post-midnight hours in contrast to their commencement in the post-sunset hours and occurrence extending to post-midnight hours in equinox. In addition, an intriguing observation of the summer time irregularities is that they occurred when the background electron density was remarkably low as characterized by the disappearance of the F layer trace in the ionograms. An interesting event of equinox that was observed for 10 h and extended beyond the sunrise time displayed multiple plume structures having periods similar to those of the E-region velocity variations. These observations are discussed with due focus on the genesis of post-midnight F-region irregularities and their possible linkage to the E-region dynamics.
Study of Various Factors for Enhancement of Artemisinin in Artemisia Annua Hairy Roots
Nivedita Patra,A. K. Srivastava,Shilpi Sharma
International Journal of Chemical Engineering and Applications , 2013, DOI: 10.7763/ijcea.2013.v4.284
Abstract: Artemisinin is an alternate anti-malarial drug which is widely used in the cure of multi-drug resistant Plasmodium falciparum malaria. In this study, enhancement of artemisinin content by using several elicitors and precursors was attempted initially by using one at a time (OVAT) approach. The most potent elicitor(s) & precursor were thereafter identified by the detailed analysis of the responses with respect to biomass and bioactive compound with respect to the concentrations of different effectors. Central Composite Design (CCD) was thereafter used to identify the antagonistic or synergistic effects of high and low concentrations of different precursors and elicitors. The maximum artemisinin content obtained was 3.45 mg/g on 15d by using the elicitor methyl jasmonate (40 μg/l) and the precursors casein acid hydrolysate (50 μg/l), sodium acetate (500 μg/l). Effect of addition time of elicitors and precursors on overall optimum biomass growth and artemisinin yield and productivity was also established.
On the stability and the similarity of N=82 isotones
P. Arumugam,S. K. Patra,A. Abbas
Physics , 2003,
Abstract: Here we study the stability and the similarity of all even $58\leq Z\leq 70, N=82 isotones. We confirm the two decades old study of one of the authors (AA) regarding the extra-ordinary stability and the similarity of these nuclei. We present here a new evidence which shows very strongly the said magicity of those nuclei and as such there exists a new ``plateau'' of magicity. Three well studied theoretical models which have been successfully applied in nuclear physics are used here to study the above phenomena. None of these model is able to reproduce the similarity and the doubly magic character of these nuclei. Therefore this hints at ``new physics'' in these N=82 isotones.
Antimicrobial Activity of Organic Solvent Extracts of Three Marine Macroalgae From Chilika Lake, Orissa, India
Patra, J. K.,Patra, A. P.,Mahapatra, N. K.,Thatoi, H. N.
Malaysian Journal of Microbiology , 2009,
Abstract: In vitro study of antibacterial activity of organic solvent extracts of three marine macroalgae viz., Chaetomorpha linum (Mell) Kuetzing, Enteromorpha compressa (L) Greville and Polysiphonia subtilissima Mont. showed specific activity in inhibiting the growth of three Gram-negative bacteria (Shigella flexneri, Vibrio cholerae and Escherichia coli) and two Gram positive bacteria (Bacillus subtilis and Bacillus brevis). The results revealed that the chloroform and ethyl acetate extracts were active against most of the pathogens whereas methanol and ethanol extracts were active only against S. flexneri.
Limnological Studies Related to Physico-Chemical Characteristics of Water of Santragachi and Joypur Jheel, W.B., India
A. Patra,K.B. Santra,C.K. Manna
Our Nature , 2010, DOI: 10.3126/on.v8i1.4328
Abstract: The present study deals with the seasonal limnological investigation related to physico-chemical characteristics of water of the Santragachi and Joypur Jheel, West Bengal, India. Besides temperature and meteorological data, 17 limnological parameters were tested following standard methods at 3 sampling sites/stations of each Jheel. The physico-chemical parameters (transparency, pH, DO, BOD, COD, free CO 2, total alkalinity, conductivity, CaCO 3, TSS, TDS, Chloride, Ammonia, Nitrite, Nitrate, Phosphate, etc.) showed distinct temporal or seasonal variation in both the Jheels. Higher nutrient contents (nitrate, phosphate) are present in Santragachi Jheel. This finding also signifies eutrophication/higher trophic level. Water transparency, dissolved oxygen, BOD, total alkalinity, conductivity, CaCO 3 hardness, TSS, nitrate and phosphate was correlated with various physico-chemical parameters in both the Jheels. ?The physico-chemical characteristics of water of the two Jheels revealed the poor water quality in Santragachi Jheel than the Joypur Jheel. These characteristics showed maximum contamination of water due to sewage effluents in Santragachi Jheel. The two years (February, 2000 - January, 2002) survey reflects higher degree of pollution in Santragachi Jheel. DOI: 10.3126/on.v8i1.4328
First simultaneous lidar observations of sodium layers and VHF radar observations of E-region field-aligned irregularities at the low-latitude station Gadanki
S. Sridharan, A. K. Patra, N. Venkateswara Rao,G. Ramkumar
Annales Geophysicae (ANGEO) , 2009,
Abstract: Simultaneous observations of atmospheric sodium (Na) made by a resonance lidar and E-region field-aligned-irregularities (FAI) made by the Indian MST radar, both located at Gadanki (13.5° N, 79.2° E) and horizontal winds acquired by a SKiYMET meteor radar at Trivandrum (8.5° N, 77° E) are used to investigate the relationship among sodium layer, FAI and neutral winds in the mesosphere and lower thermosphere region. The altitudes and descent rates of higher altitude (~95 km) Na layer and FAI agree quite well. The descending structures of the higher altitude Na layer and FAI are found to be closely related to the diurnal tidal phase structure in zonal winds observed over Trivandrum. At lower altitudes, the descent rate of FAI is larger than that of Na layer and zonal tidal phase. These observations support the hypothesis that the metallic ion layers are formed by the zonal wind shear associated with tidal winds and subsequently get neutralized to manifest in the form of descending Na layers. The descending FAI echoing layers are manifestation of the instabilities setting in on the ionization layer. In the present observations, the altitudes of occurrence of Na layer and FAI echoes being low, we surmise that it is quite possible that the FAI echoes are due to the descent of already formed irregularities at higher altitudes.
Equatorial Spread F structures and associated airglow intensity variations observed over Gadanki
R. Sekar, D. Chakrabarty, R. Narayanan,A. K. Patra
Annales Geophysicae (ANGEO) , 2008,
Abstract: Co-ordinated campaigns have been conducted from Gadanki (13.5° N, 79.2° E, dip lat 6.4° N) by operating simultaneously the Indian MST radar in ionospheric coherent backscatter mode and by monitoring thermosphere airglow line emissions (630.0 nm and 777.4 nm) using a narrow band multi-wavelength scanning photometer during January-March for the past five years (2003–2007) and also during April 2006, as a special campaign. Simultaneous radar and optical observations reveal optical signatures corresponding to a variety of equatorial spread F (ESF) structures. The optical signatures corresponding to ESF structures with wave-like bottomside modulations with plasma plumes, confined bottomside flat and wavelike structures, vertically extended plume structure in the absence of bottomside structure apart from the classical plasma depletions and enhancements are obtained during these campaigns. The plasma depletions and enhancements were identified using optical measurements. In addition, estimations of zonal wavelength of the bottomside structures and the inference of shears in the zonal plasma drift in the presence of confined structures, were carried out using bi-directional airglow measurements. Furthermore, it is found that the vertical columnar intensity of OI 630.0 nm airglow exceeded the slanted columnar intensity in the presence of large bottomside structure. The need for the appropriate physical mechanisms for some of the ESF structures and their characterizations with optical observations are discussed.
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