Modelling the Vertical Transport of Pollutants by Fronts

A quantitative study of the amount of air transported between the boundary layer and the free atmosphere is important for understanding air quality and upper tropospheric ozone, which is a greenhouse gas. Frontal systems are known to be an effective mechanism for the vertical transport of pollutants. Numerical experiments have been performed with a simple two-dimensional front model to simulate vertical transport of trace gases within developing cold fronts. Three different trace gases experiments have been done numerically according to the different initial fields of trace gases such as aerosol, ozone and H₂O₂. Trace gas field tilts to the east while the front tilts to the west. Aerosol simulation shows that pollutants can be transported out of the boundary to altitudes of about 10 km. The stratospheric ozone is brought downwards in a tropopause fold behind of the frontal surface. The meridional gradient in trace gas (H₂O₂) can cause a complicate structure in the trace field by the meridional advection.     

Immobilization of Cationic Titanium Dioxide (TiO<Subscript>2</Subscript><Superscript>+</Superscript>) on Electrospun Nanofibrous Mat: Synthesis,Characterization, and Potential Environmental Application

We report a facile approach to fabrication and characterization of cationic titanium dioxide (TiO₂⁺) on poly (vinyl alcohol)/poly (acrylic acid) (PVA/PAA) composite electro-spun nanofibrous mat. The aim of this study is to develop a “functional electrospun nanofibrous mat” as a sustainable approach to superior photocatalytic degradation of organic colorants. For that, the PVA/PAA nanofibrous mat was prepared by electrospinning of PVA and PAA solution according to an aspect ratio of 1:1 and later water stability was induced by the thermal cross linking at an elevated temperature of 145 °C for 30 minute. By means of electrostatic layer-by-layer (LbL) assembly, cationic titanium dioxide (TiO₂⁺, ~19 nm) was immobilized on the surface of the water stable nanofibrous mat. As functionalized composited nanofibrous mat was characterized by using scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis and thermogravimetric analysis (TGA). Superior competency of the functionalized nanofibrous mat towards photocatalytic degradation of organic dye (methyl blue) in aqueous solution was observed by using UV-visible spectrophotometer with quantitative measuring method. The result indicates a complete degradation of methyl blue within 40 mins and superior reusability upto 5 cycles application. The study signifies the prospect of using electrospun nanofibers to manipulate the catalytic activity, which could be a foundation for further rational design of various composite nanofibrous materials.     

Efficacy of N2O2 donor schiff bases and their Zn2+ complexes on various morphological and biochemical parameters of Cicer arietinum L.

Schiff-base polydentate ligands types of salen and salophen can form stable complexes with Zn²⁺ and these metal complexes can act as a source of zinc (Zn) to plant's body if they are used as micronutrient supplements. Inspired by these facts, four different Schiff-base ligands and their Zn²⁺ complexes were first synthesized and then characterized by different analytical and spectroscopic techniques. To investigate their effects local chickpea seeds were treated with each ligands and complexes and different morphological and biochemical parameters were monitored. Among all the complexes and ligands it was found that the C4 complex, that is, [N,N'-(o-phenylene)bis-(3-methoxysalicylidenediamine)] monohydrate showed the maximum efficacy when treated as a micronutrient supplement for Cicer arietinum L. So that these complexes especially the C4 can act as an potential source of Zn.     

Assessment of Atmospheric Arsenic Level in Airborne Dust Particulates of an Urban City of Central India

An assessment of arsenic contamination in Raipur city (21°14′N, 18°38′E) of Chhattisgarh in the central part of India is reported here, for a monitoring period between November 1996 to June 1997, in airborne dust particulates. The concentration level of As were higher in the industrial site, followed by heavy traffic as compared to other sites. The monthly atmospheric arsenic deposition, in μg As per g of dust fall, of 6 sites are in the range of 0.100(μ0.020)–4.00(μ0.020); site no. 1 industrial area, 0.100(μ0.020)–0.320(μ0.020); site no. 2 residential area, 0.044(μ0.070)–0.337(μ0.030); site no. 3 commercial area, 0.093(μ0.068)–1.870(μ0.020); site no. 4 residential area, 0.111(μ0.020)–1.912(μ0.010); site no. 5 residential area and 0.068(μ0.040)–3.037(μ0.060); site no. 6 heavy traffic area. The total annual flux of As in the fall-out at different zones is in the range 0.033–1.12 kg km^-2 yr^-1. The month wise collection and analysis of dust fall out rate between 3.0(μ0.10)–91.3(μ1.4) mt (metric tonnes) km^-2 month^-1 were observed at all 6 sampling sites. Anthropogenic and environmental factors play important roles in the contribution of arsenic in airborne particulate matters.     

CO2-forced climate and vegetation instability during Late Paleozoic deglaciation

The late Paleozoic deglaciation is the vegetated Earth's only recorded icehouse-to-greenhouse transition, yet the climate dynamics remain enigmatic. By using the stable isotopic compositions of soil-formed minerals, fossil-plant matter, and shallow-water brachiopods, we estimated atmospheric partial pressure of carbon dioxide (pCO2) and tropical marine surface temperatures during this climate transition. Comparison to southern Gondwanan glacial records documents covariance between inferred shifts in pCO2, temperature, and ice volume consistent with greenhouse gas forcing of climate. Major restructuring of paleotropical flora in western Euramerica occurred in step with climate and pCO2 shifts, illustrating the biotic impact associated with past CO2-forced turnover to a permanent ice-free world.     

Carcinogens 3,4-benzpyrene and 3-methylcholanthrene: induction of mitochondrial oxidative enzymes

Sections of liver from rats injected with 3,4-benzpyrene and 3-methylcholanthrene, when incubated in mediums specific for the histochemical demonstration of mitochondrial oxidative enzymes, show greater activity of several of these enzymes than do sections from control rats. This observation was confirmed by comparison of the staining of mitochondria isolated from the control and from "induced" rats. The fact that an inhibitor of protein synthesis, actinomycin D, effectively diminished the stimulation provided evidence that the stimulation of activity is due to an increase in enzyme synthesis, generally called induction.     

Association of bovine KISS1 single nucleotide polymorphisms with reproductive traits in Indian Cattle

Kisspeptins, a family of neuropeptide encoded by the Kiss1 gene, have emerged as crucial regulator of fertility and reproduction by regulating the hypothalamic–pituitary–gonadal axis. The present study was aimed to identify and associate SNPs in the KISS1 gene with reproductive traits in cattle of Indian origin. DNA samples collected from 300 individual cows of three Indian dairy breeds (Gir, Kankrej and Frieswal) of cattle were used in the study. The SNPs of KISS1 gene were identified with PCR-RFLP and sequence analysis using two sets of primer pairs. A total of 5 SNPs were identified in the targeted region of which, two were selected for screening the population and association studies. The analysis revealed that genotypes of rs442633552G>A and rs42022871C>T had a significant association with dry period. The SNP rs42022871C>T also established significant role in milk production traits, and selection of TT-genotyped animals will improve the reproduction and production potential of the animals.     

Nitrous oxide emission measurement with acetylene inhibition method in paddy fields under flood conditions

Nitrous oxide (N₂O) emission from flooded rice paddy fields was continuously measured by the closed chamber method at an experimental plot in Thailand for a whole cultivation period. To characterize the N₂O emission with regard to the denitrification N loss, the C₂H₂ inhibition method was applied. Flood water on the soil greatly suppressed the N₂O emission. The N₂O emission was mitigated considerably by even a thin film of the flood water. The overall average N₂O emissions under flood conditions for one crop season (83 days) at the control site and the C₂H₂ treated site were 10.3 and 11.8 μg N m⁻² h⁻¹, respectively. The N₂O emission from the C₂H₂ treated site was consistently higher than that from the control site and the N₂O emission from both sites followed the same diurnal and seasonal variation pattern, indicating the effect of denitrification inhibition by the supplied C₂H₂. The N₂O emission enhanced along with temperature increase when NO₃–N concentration in the soil water was above 0.4 mg N l⁻¹ and soil temperature was above 24°C, suggesting specific temperature influence over the emission. The increase in NO₃–N concentration and temperature in the soil affected only the N₂O emission while the difference in the emission at the C₂H₂ treated site and the control site was not so much affected. It was suggested that most of the actively produced N₂O under higher NO₃–N concentration and temperature would likely to quickly emit to the atmosphere rather than to undergo further reduction to N₂.     

Contrasting the financial efficiency of agroforestry practices in buffer zone management of Madhupur National Park, Bangladesh

This research contrasts the financial profitability of different agroforestry practices in community-based buffer zone management of Madhupur National Park (MNP), Bangladesh. This park is the second largest in Bangladesh and subjected to enormous anthropogenic pressure and land rights-related conflicts. This paper reports the different agroforestry practices of villagers in different modules of the buffer zone of MNP, identified by a participatory research approach. It then assesses the profitability of each module on the basis of cost–benefit analysis, net present value, internal rate of return, and annualized income. Results indicate three agroforestry systems were being practised in the buffer zone by the participants: agro-silviculture, agro-silvo-horticulture, and combined woodlot and agroforestry. Among these modules, agro-silvo-horticulture was the most profitable, followed by agro-silviculture then combined woodlot and agroforestry. We recognize that not all of the participants can practise intensive agroforestry; our results suggest that the community-based buffer zone management strategy for MNP would benefit from prioritizing agroforestry practices where possible. This will lead to more successful buffer zone management for the conservation of natural forests while supporting the development of local resource-dependent communities.