Toxic effects of dimecron to Labeo rohita Ham. fingerlings during acute and chronic exposures: histopathological changes

The exposure to the highest dimecron cone. (8 mg/1) resulted in severe histopathological changes in different tissues of Labeo rohita fingerling. Cell necrosis, cytoplasmic vacuolation and pycnotic nuclei were major abnormalities observed in liver tissue. The degeneration of glomeruli and proximal tubules, cytoplasmic vacuolation and focal haemorrhagic area were noted in case of kidney tissues. Major changes observed in intestinal tissues were degeneration of villi, disintegrity of mucosal layers, necrosis of epithelial cells etc. However, hypertrophy of cells and granulation of cytoplasm were major histopathological changes observed in fish at lower dimecron cones. (4 mg/1)

Toxic effects of dimecron to fingerlings of Labeo rohita (Ham.) during acute and chronic exposures

The toxic effects of dimecron on growth, body composition and oxygen consumption of fingerlings of Labeo rohita were studied. Dimecron concentrations of 4 and 8 mg/l were used. Both acute (3-h) and chronic (15- 42 d) exposure schedules were followed. Compared with the control fish, both 4 and 8 mg/l dimecron treatment significantly suppressed weight gained in fish by 9.71% and 30% respectively during a 42 day exposure period. However, the length of fish was suppressed by 11.46% significantly only in fish group exposed to 8 mg/l dimecron. Similarly, the protein content was also significantly reduced in the above group of fish. The oxygen consumption of fish was elevated considerably, but not significantly in both group of treated fish (8.5% and 26.07%) during acute exposure. However, after 15 days of exposure the rate decreased by 18.98% significantly only in fish exposed to 8 mg/l dimecron. The threshold level of DO at low oxygen environment found to be slightly higher in fish at 8 mg/l dimecron. The survival time at the above oxygen condition was reduced during acute exposure (3-h) and that was extended during chronic (15-d) exposure

Expression of Heterosis for Productive Traits in Bottle Gourd Hybrids

A study was conducted in bottle gourd to estimate the magnitude of heterosis for yield and its thirteen yield related components. Twenty one bottle gourd hybrids generated from 7 × 7 diallel cross (excluding reciprocals) along with their seven parents evaluated in a Randomized Block Design with three replication at at the Olericulture Division of Horticulture Research Centre, Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh during 2018-19. Most of the crosses showed significant heterobeltiosis for earliness. The highest heterobeltiotic effect was observed in the cross P2XP7 and P4XP7. The best heterotic cross for fruit length was P4XP5. Maximum heterotic effect in respect of fruit number per plant was found in the cross P1XP6 and P4XP6. In terms of yield per plant the highest heterobeltiosis was shown by the crosses P3XP4, P3XP5, P4XP5 and P4XP7. In the overall analysis, both additive and non-additive gene actions were found important with predominance of the additive gene effects in the inheritance of bottle gourd

Structural and magnetization behaviors of Ni substituted Li-Mg ferrites

Magnetization behaviors of Ni-substituted LixMg0.5Ni0.5-2xFe2+xO4 ferrites, where x = 0.25, 0.20, 0.15, 0.10 and 0.00 synthesized by standard ceramic technology sintered at 1300°C in air for 5 hours has been presented in the present study. The bulk density and lattice constants of the samples found to be decreased with the increase in the Ni-content for the x values from 0.25 to 0.00. DC electrical resistivity has found to show highest magnitude at room temperature and decreases with further increase in temperature. Magnetization of the samples has been measured as a function of the field using hysteresis loop tracer at 30°C. It was observed that addition of nickel in polycrystalline Li-Mg ferrites plays an important role in modification of structural and magnetization characteristics

Composition, temperature and frequency dependent magnetic, dielectric and electrical properties of magnesium-zinc ferrites

Polycrystalline spinel MgxZn0.3Cu0.7-2xFe2+xO4, where x = 0.10, 0.20, 0.25, 0.30 and 0.35 ferrites (hereafter abbreviated as Mg-Zn) have been prepared by conventional double sintering technique. The samples were sintered at 1250°C in air for 6 hours. Measurements have been done at temperature and frequency ranges of 0 - 350°C and 0 - 500 kHz, respectively. In this work, some extrinsic magnetic properties such as Curie temperature, initial permeability, loss factor, quality factor, dielectric constant and resistivity of the samples have been studied. The Curie temperature and loss tangent of the samples decreased with increase in Cu-content whereas permeability, Qfactor, resistivity and dielectric constant have been noticed to be increased with the increase in Cucontent. The decrease in Curie temperature related to fact of weakening the strength of exchange AB interaction. Maxwell-Wagner type of interfacial polarization might have found correlated with the normal dielectric behavior of the samples, however no relaxation peaks were observed in the dielectric dispersion curves of the Mg-Zn samples in virgin state or doped state

Spatio-temporal distribution of reactive nitrogen species in relation to wheat cultivation in Bangladesh

Farmers generally use more nitrogen fertilizer than others for crop production in Bangladesh because of its visible growth symptoms. Such practice is responsible for extra reactive N (Nr) load to the environment, but data are not available. Nitrous oxide (N2O) data were collected from a field trial following static closed-chamber technique, which were used for calibration and validation of DeNitrification and DeComposition model along with soil clay fraction, pH, bulk density and organic carbon contents. The model was well fitted and estimated about 364 g N2O–N ha−1 emission in Rajshahi region and only 15 g N2O–N ha−1 in Barisal region. District-wise N2O–N emissions varied from < 1–15.96 t season−1. In 2011–2016, N2O–N emissions from wheat fields were about 103–129 t yr−1 in Bangladesh. The model estimated nitric oxide (NO), ammonia (NH3) and nitrate (NO3) fluxes varied from 0.012 to 0.447, 7 to 12.5 and 0 to 4.7 kg N ha−1, respectively, under ambient temperature condition. In about 79% yield variabilities were explainable by N2O emission. In dominant wheat growing areas, if sowing is started from 15 to 30 November, N2O emission could be reduced by 8–40% with 5–13% reduction in yields compared to 10 November sowing. In similar areas and same sowing date with 1.5 °C temperature rise, N2O emission may increase by 8–45% and wheat yield might reduce by about 4–8%. Time of seeding and other cultural management in wheat cultivation would be the main avenue for reducing Nr loads to the environment

Thermal hysteresis of permeability and transport properties of Cu Substituted Ni0.28Cu0.10+ x Zn0.62– x Fe1.98O4 ferrites

Cu Substituted Ni–Cu–Zn ferrites of Composition Ni0.28Cu0.10+ x Zn0.62– x Fe1.98O4 have been prepared by the standard double sintering ceramic technique. The samples were sintered at 1150 C for 3 hours in air. The analysis of XRD patterns indicates that the samples have the single phase cubic spinel structure. The lattice constant is found to decrease linearly with increase in Cu2+ ion concentration obeying Vegard's law. The initial permeability (μ i ) of the Ni–Cu–Zn ferrites exhibits thermal hysteresis when the temperature is cycled from above the Curie temperature Tc to below. The sharp decrease of μ i at T = Tc indicates the sample's good homogeneity. The Curie temperatures, Tc of the studied ferrite samples were determined from the μ i – T curves where the Hopkinson type of peak at the Tc has been observed with the manifestation of a sharp fall in permeability. The Tc is found to increase with increasing Cu-content. DC electrical resistivity increases significantly with the increase of Cu-Content. The ac resistivity (ρ ac ) and dielectric constant (ε′) of the samples are found to decrease with increase in frequency, exhibiting normal ferrimagnetic behavior