We performed the optimization of lattice constants of Group- III nitrides (InN, AlN, GaN) in wurtzite and Zinc blende structures using various semilocal exchange correlation functional in generalized gradient approximations (GGA) namely PBE, WC, PBEsol in addition to local density approximation (LDA) functional. We used these optimized lattice parameters to predict the band gap values using modified Becke Johnson exchange potential with original and improved parameterization as suggested by David Koller for semiconductors having band gap values below 7eV. Among the different functionals considered, PBEsol optimize the lattice parameters with smallest mean error (0.00639 Å) relative to experimental values, while WC approximation with a slightly greater value of mean error (0.00513 Å). It is shown that mBJLDA approximation improves the band gap for the materials studied when compared with LDA and GGA results. It is also shown that LDA optimized parameters with mBJLDA approximation, which leads to mean error of 0.162 eV reproduces the experimental band gap in most efficient way.
Avian species diversity and their assemblage are responsible for maintaining the integrity and health of any ecosystem. Documentation of avian diversity in different habitats is sensitive tool for monitoring the environmental condition. The present investigation aimed to record the diversity of avian fauna at the main campus and agricultural landscapes of Chaudhary Charan Singh Haryana agricultural University, Hisar (Haryana). Line transect and point count methods were used to taking observations on different species of birds. A total of 101 bird species under 17 orders 43 families and 86 genera were recorded; out of them, 78, 17, 5 and one species were resident, winter migrant, summer migrant and passage migrant, respectively. Species richness of order Passeriformes was highest, followed by Pelecaniformes and Muscicapidae, the most diverse family in the study area. Analysis of food and feeding guilds revealed that the insectivorous guild is predominant, followed by Omnivore, Carnivore, Granivore, Frugivore and Nectarivore. Out of the total observed species, 23 have declining population trends at global level, whereas three species (Alexandrine Parakeet, Asian Woollyneck, Black-headed ibis) are listed as Near Threatened and Common Pochard is vulnerable as per IUCN Red List. The species richness was significantly higher in farmland, followed by main campus and experimental orchards. Jaccard’s similarity index between habitats revealed that the main campus and farmland area has a maximum (0.73) similarity in bird communities. This emphasises the significance of these study sites as key habitats for bird species of conservation priorities.
Imidacloprid is a systemic insecticide that acts as an insect neurotoxin and belongs to class of chemicals called the neonicotinoides which act on central nervous system of insects. Three concentration of imidacloprid (0.134 µl, 0.195 µl and 0.285 µl) have been used during the experiment for evaluation of enzymatic activity. The increase in superoxide dismutase (SOD) activity suggests that SOD has the capacity to scavenge reactive oxygen species (ROS) under the stress at lower concentration of imidacloprid and it also indicated that the activity of the superoxide dismutase had shown different responses to toxicity of various concentrations of imidacloprid for different exposure periods in earthworm Eisenia fetida. Imidacloprid at concentrations of 0.195 µl and 0.285µl had shown the SOD activities of 6.773 and 7.263 U/mg protein respectively at 48 hr of exposure, while a concentration of 0.285µl has showed an enzyme activity of 6.835 U/mg protein at 24 hr of exposure. The study revealed that the activity of antioxidant enzyme of earthworms is altered due to stress produced by neonicotinoid insecticide. The statistical data of pesticide is highly significant with respect to treatment and time of exposure.
Because of their high biomass in the soil, earthworms are used as bio-indicator species for assessing soil toxicity against pesticides. The regular observed sensitivity to relatively low pesticide concentrations exits in soils is a significant ecological observation. Insecticide residues harm the flora of beneficial invertebrates and harm the physiological functions of earthworms, resulting in death. They affect morphological parameters as well as internal organs, and eight different imidacloprid concentrations (0.050 µl/cm2, 0.100 µl/cm2, 0.150 µl/cm2, 0.200 µl/cm2, 0.250 µl/cm2, 0.300 µl/cm2, 0.350 µl/cm2, 0.400 µl/cm2) were prepared with water during the procedure. To establish the LC50 value, earthworms of Eisenia fetida were exposed to various concentrations of imidacloprid using the usual paper contact toxicity method, and their toxicity levels are established. The mortality percentage was estimated after 24 hours of imidacloprid exposure, and a dosage of 0.195 µl/cm2 resulted in 50% mortality of earthworms. When higher concentrations of imidacloprid were used, negative effects were observed. For ecotoxicological evaluations, the following morphological and behavioural changes were observed during the experiment: Preclittelar bulging, body constriction, blackening of the body, segment swelling, oozing of coelomic fluid, body constriction, cuticle rupture, and oozing of fluid from the body are all common side effects.
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