Impact of Changes in Management Regime on Fisheries: A Temporal Case Study of Dhir Beel in Assam

The floodplain wetlands (beels) constitute important fisheries resources of Assam. These resources are managed through a complex social framework. The state of this management regime determines the level and sustainable utilization with implications on fisheries and livelihoods. To find the impact of such management regime, a case study has been undertaken in the Dhir beel of Assam. The impact of the change in the management regime on the sustainability of fisheries and livelihoods of fishers has been evaluated. This change in the management regime has been due to immigration of a large number of people from the nearby areas since 1985. The study has compared the scenario that existed ‘before 1985’ (data of 1982-84) and “after 1985’ (data of 2004). There has been a significant increase in the fishing pressure with new fishing practices (1.5 to 5 times) as well as intensity of effort (3 to 7 times). The weakening of the regulating institutions has led to irrational practices which in turn, have resulted in a decline (22.32%) in the production and productivity of the beel. The decline has been more (31.79%) in terms of value than production of fish, indicating a definite decline in the quality of the fish available in these resources. In the changed scenario, the economics of the management has gone against the resource managers as they are to spend more money on monitoring and enforcing the rules. The livelihood of the fishers has also declined with the high degree of sharing of fish among the fishers.Resource /Energy Economics and Policy,

Processing of dust materials from Indian copper plants

In the pyrometallurgical processing of copper are, there is considerable amount of copper losses in the form of dust from the roaster, smelter and converter. Most of this dust is simply charged back into the smelting cir¬cuit, thereby reducing the capacity offresh charge processing. In the present paper separate processing of copper dust sample by sulphuric acid leaching method has been examined with the idea that the resulting leached cop¬per sulphate solution can be used as electrolyte in the copper electro¬refining section of the plant. The copper dust sample from Khetri Copper Complex, Rajsthan contained about 22% copper. The XRD analysis of the sample revealed that copper was mainly present in the forms of ox¬ides, sulphates and sulphides. Simple water leaching of the dust sample dissolved copper to the tune of 30%. This implied that about 30% of cop¬per was present in the sulphate form and rest of the copper was in the oxide and sulphide forms for which acid leaching process might be suit¬able. Sulphuric acid leaching at various concentration and at varied solid : liquid ratio, time and temperature were carried out at atmospheric pressure. The maximum recovery of copper obtained in these experiments was found to be about 52%. Since the sulphuric acid leaching at atmospheric presssure did not yield good results, the dust sample was leached at higher pressure in an autoclave on 200 g scale and the recovery of copper improved to 80%

Reduction of Emission from Aluminium Industries and Cleaner Technology

Aluminium metal is produced by electrolytic reduction of alumina in cells lined with carbon blocks. During the process of smelting different gaseous emissions like PFC (per flurocarbon).HF PAH (poly aromatic hydrocarbon), CO2, SO„ particulate matters etc. occur in to the atmosphere. The concentration of emission from a cell depends upon the type of cell, bath chemistry, scrubbing system and gas cleaning equipment used. These emissions cause severe environmental damages such as global warming and disease like fluorosis, cancer, asthma, emphysema, bronchitis etc. Through the development of newer technologies like, intro-duction of prebake technology, use of non-consumable (inert) anode, use of computer controlled and point feeding of alumina to the cell to control the frequency and duration of anode effects, use of low carbon pitch to replace tar, use of pollution monitoring and control equipment etc., there is a significant reduction in the emission levels. This paper deals with the factors infl-uencing the generation of these emissions and its reduction through the development of various cleaner technologies. Use of pollution control equipment and other remedial mea-sures to minimise the environmental pollution are also discussed

Chemical modeling for predicting the abundances of certain aldimines and amines in hot cores

We consider six isomeric groups (CH3N, CH5N, C2H5N, C2H7N, C3H7N and C3H9N) to review the presence of amines and aldimines within the interstellar medium (ISM). Each of these groups contains at least one aldimine or amine. Methanimine (CH2NH) from CH3N and methylamine (CH3NH2) from CH5N isomeric group were detected a few decades ago. Recently, the presence of ethanimine (CH3CHNH) from C2H5N isomeric group has been discovered in the ISM. This prompted us to investigate the possibility of detecting any aldimine or amine from the very next three isomeric groups in this sequence: C2H7N, C3H7N and C3H9N. We employ high-level quantum chemical calculations to estimate accurate energies of all the species. According to enthalpies of formation, optimized energies, and expected intensity ratio, we found that ethylamine (precursor of glycine) from C2H7N isomeric group, (1Z)-1-propanimine from C3H7N isomeric group, and trimethylamine from C3H9N isomeric group are the most viable candidates for the future astronomical detection. Based on our quantum chemical calculations and from other approximations (from prevailing similar types of reactions), a complete set of reaction pathways to the synthesis of ethylamine and (1Z)-1-propanimine is prepared. Moreover, a large gas-grain chemical model is employed to study the presence of these species in the ISM. Our modeling results suggest that ethylamine and (1Z)-1-propanimine could efficiently be formed in hot-core regions and could be observed with present astronomical facilities. Radiative transfer modeling is also implemented to additionally aid their discovery in interstellar space.Comment: 32 pages, 18 Figures, Accepted for publication in the Astrophysical Journa

Chemical and radiative transfer modeling of Propylene Oxide

The recent identification of the first complex chiral molecule, propylene oxide (PrO) in space opens up a new window to further study the origin of homochirality on the Earth. There are some recent studies to explain the formation of PrO however additional studies on the formation of this species are needed for better understanding. We seek to prepare a complete reaction network to study the formation of propylene oxide in the astrophysically relevant conditions. Based on our results, a detailed radiative transfer modeling has been carried out to propose some more transitions which would potentially be targeted in the millimeter wave domain. Gas-grain chemical network was used to explain the observed abundance of PrO in a cold shell surrounding the high-mass star-forming region of Sgr B2. Quantum chemical calculations were employed to study various reaction parameters and to compute multiple vibrational frequencies of PrO. To model the formation of PrO in the observed region, we considered a dark cloud model. Additionally, we used a model to check the feasibility of forming PrO in the hot core region. Some potential transitions in the millimeter wave domain are predicted which could be useful for the future astronomical detection. Radiative transfer modeling has been utilized to extract the physical condition which might be useful to know the properties of the source in detail. Moreover, vibrational transitions of PrO has been provided which could be very useful for the future detection of PrO by the upcoming James Webb Space Telescope (JWST).Comment: 35 pages, 15 figures, Accepted for the publication in Astronomy and Astrophysic

Effect of Binding Energies on the Encounter Desorption

The abundance of interstellar ice constituents is usually expressed with respect to the water ice because, in denser regions, a significant portion of the interstellar grain surface would be covered by water ice. The binding energy (BE) or adsorption energy of the interstellar species regulates the chemical complexity of the interstellar grain mantle. Due to the high abundance of water ice, the BE of surface species with the water is usually provided and widely used in astrochemical modeling. However, the hydrogen molecules would cover some part of the grain mantle in the denser and colder part of the interstellar medium. Even at around similar to 10 K, few atoms and simple molecules with lower adsorption energies can migrate through the surface. The BE of the surface species with H-2 substrate would be very different from that of a water substrate. However, adequate information regarding these differences is lacking. Here, we employ the quantum chemical calculation to provide the BE of 95 interstellar species with H-2 substrate. These are representative of the BEs of species to a H-2 overlayer on a grain surface. On average, we notice that the BE with the H-2 monomer substrate is almost ten times lower than the BE of these species reported earlier with the H2O c-tetramer configuration. The encounter desorption of H and H-2 was introduced [with E-D (H, H-2) = 45 K and E-D (H-2, H-2) = 23 K] to have a realistic estimation of the abundances of the surface species in the colder and denser region. Our quantum chemical calculations yield higher adsorption energy of H-2 than that of H [E-D (H, H-2) = 23-25 K and E-D (H-2, H-2) = 67-79 K]. We further implement an astrochemical model to study the effect of encounter desorption with the present realistic estimation. The encounter desorption of the N atom [calculations yield E-D (N, H-2) = 83 K] is introduced to study the differences with its inclusion

Airway management in cardiac arrest -- not a question of choice but of quality?

This study presented an innovative method in order to estimate training required for skilful and successful intubations during ED cardiac arrests. Video reviews were taken from a system that routinely records ED staff during cardiac arrests and as these recordings are already part of everyday clinical practice, it is likely that there is minimal Hawthorne effect. Cardiac arrest research often reiterates the fact that the basics should be done well. It is commendable that intubations by the residents in this observational study resulted in a modest mean delay in chest compressions of only 8.6 seconds for the intubation attempt. However, nearly a third of intubation attempts were unsuccessful at the first attempt, and there were 11 oesophageal intubations (albeit they were all recognised) in the 93 patients that were included

Host-guest interaction of cucurbit[7]uril with para-nitrophenol: A weakly binding inclusion complex

Host-guest interaction between water soluble rigid molecular container cucurbit[7]uril (CB[7]) and a water soluble organic guest para-nitrophenol (PNP) has been investigated using 1H NMR spectroscopy and isothermal titration calorimetry. The stoichiometry, binding constant and other thermodynamic parameters of complexation have been obtained which show the formation of weakly binding 1:1 inclusion complex resulting from enthalpy-entropy compensation. Cyclic voltammetry study of PNP-CB[7] complex in acidic pH reveals a large cathodic shift in the reduction potentials of PNP, indicating either stabilization of PNP or destabilization of the electro-reduced product inside CB[7] cavity