Chowdhury U.,B Borooah College |
Tanti B.,Gauhati University |
Rethy P.,NERIST |
Applied Biochemistry and Biotechnology | Year: 2014
The utility of RAPD markers in assessing genetic diversity and phenetic relationships of six different species of Piper from Northeast India was investigated. Polymerase chain reaction (PCR) with four arbitrary 10-mer oligonucleotide primers applied to the six species produced a total of 195 marker bands, of which, 159 were polymorphic. On average, six RAPD fragments were amplified per reaction. In the UPGMA phenetic dendrogram based on Jaccard’s coefficient, the different accessions of Piper showed a high level of genetic variation. This study may be useful in identifying diverse genetic stocks of Piper, which may then be conserved on a priority basis. © 2014, Springer Science+Business Media New York.
Sharma P.,Cotton College |
Deka D.,B Borooah College |
Saikia R.,Cotton College
Hungarian Geographical Bulletin | Year: 2011
Land use change is accelerating throughout Northeast India and is the cause of many environmental problems. The Umtrew is a major river that originates on the Meghalaya Plateau, fl ows down to the Assam Valley, and is one of the tributaries of the Brahmaputra (Roy, P.S. and Tomar, S. 2001). The Umtrew Basin covers an area of 1253.1 sq km, mostly in the foothills of the Meghalaya Plateau. Remote sensing and GIS techniques are used to explore the changing patt ern of land use/land cover. The study employs satellite data from Landsat-MSS and IRS-1C LISS III for the years 1977, 1999, 2004 and 2007. Its aim is to formulate a plan/strategy for maintaining environmental quality.
Choudhury D.,B Borooah College |
Banik A.,B Borooah College |
Sarma R.,Indian Institute of Technology Guwahati
Acta Crystallographica Section C: Crystal Structure Communications | Year: 2010
In the title compound, C19H15NO, the neutral mol-ecules are held together in the crystal structure by very weak C - H⋯O inter-actions, giving rise to a linear chain-like structure. The structure of the mol-ecule has been optimized using density functional theory at the B3LYP/6-31G(d) level and this is compared with the mol-ecular structure in the solid state. The two structures show significant differences in the relative orientations of the aromatic rings, which is inter-esting for further supra-molecular study. Apart from the crystal structure analysis, powder X-ray diffraction, UV-visible and thermogravimetric analyses of the compound have been carried out. © 2010 International Union of Crystallography.
Majumdar H.C.,B Borooah College |
Shyam J.,Nowgong College
Plant Archives | Year: 2013
In the present paper, 20 plant species belonging to 17 families used for treatment of Jaundice in Nalbari District of Assam have been documented. The ethnobotanical information regarding vernacular name, family name, mode of preparation are provided. Different plant parts namely leaf, stem, root, bark, fruits and even whole plants are administered either raw or with some medium. The presence of alkaloids in the plant parts used was tested by using Mayer's reagents, Dragendroff's reagent and Wegner's reagent.
See L.,International Institute For Applied Systems Analysis |
Schepaschenko D.,International Institute For Applied Systems Analysis |
Lesiv M.,Lviv Polytechnic |
Lesiv M.,Polish Academy of Sciences |
And 23 more authors.
ISPRS Journal of Photogrammetry and Remote Sensing | Year: 2015
Land cover is of fundamental importance to many environmental applications and serves as critical baseline information for many large scale models e.g. in developing future scenarios of land use and climate change. Although there is an ongoing movement towards the development of higher resolution global land cover maps, medium resolution land cover products (e.g. GLC2000 and MODIS) are still very useful for modelling and assessment purposes. However, the current land cover products are not accurate enough for many applications so we need to develop approaches that can take existing land covers maps and produce a better overall product in a hybrid approach. This paper uses geographically weighted regression (GWR) and crowdsourced validation data from Geo-Wiki to create two hybrid global land cover maps that use medium resolution land cover products as an input. Two different methods were used: (a) the GWR was used to determine the best land cover product at each location; (b) the GWR was only used to determine the best land cover at those locations where all three land cover maps disagree, using the agreement of the land cover maps to determine land cover at the other cells. The results show that the hybrid land cover map developed using the first method resulted in a lower overall disagreement than the individual global land cover maps. The hybrid map produced by the second method was also better when compared to the GLC2000 and GlobCover but worse or similar in performance to the MODIS land cover product depending upon the metrics considered. The reason for this may be due to the use of the GLC2000 in the development of GlobCover, which may have resulted in areas where both maps agree with one another but not with MODIS, and where MODIS may in fact better represent land cover in those situations. These results serve to demonstrate that spatial analysis methods can be used to improve medium resolution global land cover information with existing products. © 2014 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).
Hazarika R.,B Borooah College |
Saikia A.,Gauhati University
International Journal of Remote Sensing | Year: 2013
Remote sensing and geographic information systems (GISs) are increasingly being used in protected area monitoring and habitat suitability studies. In this article, Erdas Imagine's Expert Classifier tool was used to assess the specific trajectories of habitat suitability change during 1994-2007 in the Sonitpur elephant habitat, India. Sonitpur has been witness to increasing human-elephant conflict in the past decade. The suitability analysis took into account information relating to forest type and density, elevation, slope, source of water, human activities in terms of settlement, agriculture, tea plantations, roads, and railways. Satellite imagery, data from topographical maps, digital elevation data, and global positioning system readings formed the major data inputs that were incorporated into a GIS. Various decision rules were created and confidence levels assigned to the input layers to generate high, medium, and low habitat suitability. The area witnessed a sharp decline in suitability from 63% in 1994 to less than 38% by 2007. The high-suitability area declined by more than 50% during this period. The unique natural protected areas of Sonitpur, which are a mix of reserved forests, wildlife sanctuaries, and a national park, urgently need to be protected from further habitat degradation. © 2013 Copyright 2013 Taylor & Francis.
Borah R.,Tezpur University |
Banerjee S.,Tezpur University |
Banerjee S.,B Borooah College |
Kumar A.,Tezpur University
Synthetic Metals | Year: 2014
Polyaniline nanofibers have been synthesized by dilute polymerization technique and functionalized with glutaraldehyde under acidic condition. The effects of surface functionalization of polyaniline nanofibers on their structural, conformational, and optical properties have been investigated using transmission electron microscopy (TEM), X-ray diffraction, UV-visible, infrared, and fluorescence spectroscopy. TEM and UV-vis spectroscopy results depict that fiber diameter is decreased from 35.66 to 31.04 nm on functionalization. XRD analysis suggests increased doping of surface functionalized polyaniline nanofibers (SF-PNFs) than that of the pristine polyaniline nanofibers (PNFs). Evolution of fluorescence peak at 452 nm in the fluorescence spectra and disappearance of absorption peak at 630 nm in the absorption spectra of surface functionalized polyaniline nanofibers (SF-PNFs) can be explained on the basis of the dynamic block co-polymeric structure of polyaniline (PAni). Study of optical properties shows that surface functionalization of polyaniline nanofibers (PNFs) brings about a partial transition of emeraldine base (EB) into emeraldine salt (ES) form of polyaniline. This is confirmed from the FTIR analysis, which depicts rearrangement in the polyaniline chain due to oxidation at the amine sites of benzenoid rings and reduction at the imine sites of quinoid rings after functionalization with glutaraldehyde due to its higher reactivity towards amine group. The possible mechanisms of functionalization of polyaniline nanofibers depending on different chemical structures of glutaraldehyde under acidic condition have been discussed in detail. © 2014 Elsevier B.V. All rights reserved.
Deka R.K.,Gauhati University |
Bhattacharya A.,B Borooah College
International Journal of Physical Sciences | Year: 2011
The effect of transverse magnetic field on the flow past an infinite vertical plate, immersed in a stably stratified fluid has been investigated. The non-dimensional governing equations are solved by Laplace transform technique. Numerical computations for velocity, temperature, plate heat flux and skin-friction are made for different values of the physical parameters and shown in graphs. Important observations due to the effect of thermal stratification is made and compared with the case of no stratification. It is observed that due to the application of transverse magnetic field on the flow, the steady state is reached at smaller times. © 2011 Academic Journals.
PubMed | B Borooah College
Type: Journal Article | Journal: Applied biochemistry and biotechnology | Year: 2014
The utility of RAPD markers in assessing genetic diversity and phenetic relationships of six different species of Piper from Northeast India was investigated. Polymerase chain reaction (PCR) with four arbitrary 10-mer oligonucleotide primers applied to the six species produced a total of 195 marker bands, of which, 159 were polymorphic. On average, six RAPD fragments were amplified per reaction. In the UPGMA phenetic dendrogram based on Jaccards coefficient, the different accessions of Piper showed a high level of genetic variation. This study may be useful in identifying diverse genetic stocks of Piper, which may then be conserved on a priority basis.
PubMed | Gauhati University and B Borooah College
Type: | Journal: Journal of insect science (Online) | Year: 2015
Differential hemocyte count of circulating plasmatocytes (PL) and granulocytes (GR) of fifth-instar larvae of Muga Silkworm Antheraea assama Westwood (Lepidoptera: Saturniidae) reared at four different sericulture farms situated at different altitudes, viz, Khanapara State Sericulture Farm, Assam, altitude 55.5m above sea level (ASL); Nongpoh (Central Silk Board farm), Meghalaya, altitude 464m ASL; Tura (Central Silk Board farm), West Garo Hills, Meghalaya, 657m ASL; and Kalimpong (Central Silk Board farm), West Bengal, altitude 1,247m ASL, were calculated and compared to investigate the effect of altitude on the number of PL and GR per mm(3) of larval hemolymph. The investigation showed that the mean circulating PL and GR were highest at Khanapara (55.5m ASL) located at the lowest altitude, whereas their numbers gradually decreased with increase in altitude at Nongpoh (464m ASL), Tura (657m ASL), and Kalimpong (1,247m ASL). This may be attributed to the average environmental temperatures observed at different altitudes, which may affect the overall hemocyte load of larval stages reared at those altitudes.