Pradeep A.K.,University of Calicut |
Pramod C.,Government Brennen College
Candollea | Year: 2013
Parasopubia hofmannii Pradeep & Pramod and Parasopubia hofmannii var. albiflora Pradeep & Pramod (Orobanchaceae) are two new taxa described from South India. They are compared with the Indian species Parasopubia delphinifolia (L.) H.-P. Hofm. & Eb. Fisch. Detailed descriptions, illustrations and taxonomical note are provided. A key for the identification of the Indian species of Parasopubia H.-P. Hofm. & Eb. Fisch. is also provided. © CONSERVATOIRE ET JARDIN BOTANIQUES DE GENÈVE 2013.
Mathew S.,Government Brennen College |
Sunitha M.S.,National Institute of Technology Calicut
Information Sciences | Year: 2010
The fuzzy graph approach is more powerful in cluster analysis than the usual graph - theoretic approach due to its ability to handle the strengths of arcs effectively. The concept of node-strength sequence is introduced and is studied in a complete fuzzy graph. Two new connectivity parameters in fuzzy graphs namely, fuzzy node connectivity (κ) and fuzzy arc connectivity (κ′) are introduced and obtained the fuzzy analogue of Whitney's theorem. Fuzzy node cut, fuzzy arc cut and fuzzy bond are defined. Fuzzy bond is a special type of a fuzzy bridge. It is proved that at least one of the end nodes of a fuzzy bond is a fuzzy cutnode. It is shown that κ = κ′ for a fuzzy tree and it is the minimum of the strengths of its strong arcs. The relationships of the new parameters with already existing vertex and edge connectivity parameters are studied and is shown that the value of all these parameters are equal in a compete fuzzy graph. Also a new clustering technique based on fuzzy arc connectivity is introduced. © 2009 Elsevier Inc. All rights reserved.
Antony J.V.,Cochin University of Science and Technology |
Antony J.V.,Government Brennen College |
Chandran P.,Cochin University of Science and Technology |
Kurian P.,Cochin University of Science and Technology |
And 2 more authors.
Journal of Physical Chemistry C | Year: 2015
A simple aqueous method has been used for the direct synthesis of water-soluble sulfonated polystyrene (SPS) encapsulated CdS quantum dots (QDs). The aqueous solution of the QDs, stabilized by two SPSs of different sulfonation level, shows a blue shift in ultraviolet-visible (UV-vis) absorption and band edge emission. High resolution transmission electron microscope (HR-TEM) establishes the presence of quantum confined CdS particles. The sulfonation level of SPS influences the size of QDs and strongly affects the photoluminescence (PL). The CdS QDs passivated by SPS with less sulfonation level exhibit only band edge emission (463 nm), while QDs in aqueous solution of SPS with high sulfonic acid content emits predominantly defect state emission (610 nm) against the band edge emission (463 nm). The PL of the SPS-CdS nanocomposites demonstrates an interesting variation in emission spectra and quantum yield via the change in sulfonation level, the change in pH and on keeping in aqueous solution. In addition, the z-scan measurements show negative nonlinear refraction coefficient, indicating self-defocusing phenomena. The absolute value of the third order nonlinear refractive index and nonlinear absorption are decided by the CdS QDs surface chemistry. © 2015 American Chemical Society.
Venugopalan Nambiar M.,Government Brennen College
Journal of Advanced Zoology | Year: 2012
Monthal, is one of the tributary of Mane river. It forms an extensive system of small streams and rivulets when it closes to the point culminating with sea. it is rich with both mangrove flora and fauna. Due to extensive destruction of mangrove vegetation or land filling, depending fauna, more precisely the fishes were found severely affected and majority of the fishes are in endangered condition at least with respect to Mahe river system. The surrounding paddy fields, the breeding centre of many freshwater fishes, also filled for housing and other human activities and deposition of waste materials. Once, this area is popularly known for both freshwater and estuarine edible fishes. The present study forms status study of ichthyo-fauna of this river. There 13 edible fish species are identified and reported in the present study. It stresses the importance of urgent measure to conserve that ichthyo-fauna of this region which are vulnerable at present. Further the shelled fishes also seen depleted in its average landings. The water qualities of the river, such as, salinity, pH, biological parameters and presence of toxic heavy metals were examined by means of standard methods. The accumulation of toxic heavy metals leads the destruction of ichthyo-fauna and they enter into human body through food chain causes severe hazardous problems to human health.
Nishanth T.,Sree Krishna College Guruvayur |
Praseed K.M.,Sir Syed College |
Satheesh Kumar M.K.,Government Brennen College |
Valsaraj K.T.,Louisiana State University
Aerosol and Air Quality Research | Year: 2014
This paper presents the results of measurements of the surface ozone (O3), oxides of nitrogen (NOx), methane (CH4) and total non-methane hydrocarbons (TNMHCs) in a rural coastal location at Kannur (11.9°N, 75.4°E, 5 m asl), India from November 2009 to December 2011. The diurnal cycle for surface O3 had a peak in the afternoon and declined during nighttime. The maximum and minimum mixing ratio of surface O3 was observed in winter and monsoon seasons respectively. NOx concentration was high during mid-night to early morning and low during noontime. The diurnal variations of mixing ratios for NOx and O3 were anti-correlated. Monthly average maximum (2.26 ± 0.44 ppmv) and minimum (0.43 ± 0.19 ppmv) CH4 concentrations were observed in December and August respectively. The diurnal variations of CH4 were similar to that of NOx. A CH4 buildup was observed during early morning hours throughout the observational period. On an annual basis, the maximum, minimum and average total NMHCs were (25.45 ± 6.58 ppbv), (13.84 ± 4.31 ppbv), and (19.23 ± 5.56 ppbv) respectively at the observational site. Analysis of O3, NO, NO2, CH4 and NMHC have been carried out and the correlation between O3 and its precursors is discussed detailed. Further, the diurnal variation of O3 over a free tropospheric region at Ooty, a hill station lying in the Western Ghats region of south India on clear sky days in February 2011 is also reported for a comparison. © Taiwan Association for Aerosol Research.