1,998 research outputs found

    Designing fuzzy rule based classifier using self-organizing feature map for analysis of multispectral satellite images

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    We propose a novel scheme for designing fuzzy rule based classifier. An SOFM based method is used for generating a set of prototypes which is used to generate a set of fuzzy rules. Each rule represents a region in the feature space that we call the context of the rule. The rules are tuned with respect to their context. We justified that the reasoning scheme may be different in different context leading to context sensitive inferencing. To realize context sensitive inferencing we used a softmin operator with a tunable parameter. The proposed scheme is tested on several multispectral satellite image data sets and the performance is found to be much better than the results reported in the literature.Comment: 23 pages, 7 figure

    A tight coupling between β\u3csub\u3e2\u3c/sub\u3eY97 and β\u3csub\u3e2\u3c/sub\u3eF200 of the GABA\u3csub\u3eA\u3c/sub\u3e receptor mediates GABA binding

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    The GABAA receptor is an oligopentameric chloride channel that is activated via conformation changes induced upon the binding of the endogenous ligand, GABA, to the extracellular inter-subunit interfaces. Although dozens of amino acid residues at the α/β interface have been implicated in ligand binding, the structural elements that mediate ligand binding and receptor activation are not yet fully described. In this study, double-mutant cycle analysis was employed to test for possible interactions between several arginines (α1R67, α1R120, α1R132, and β2R207) and two aromatic residues (β2Y97 and β2F200) that are present in the ligand-binding pocket and are known to influence GABA affinity. Our results show that neither α1R67 nor α1R120 is functionally coupled to either of the aromatics, whereas a moderate coupling exists between α1R132 and both aromatic residues. Significant functional coupling between β2R207 and both β2Y97 and β2F200 was found. Furthermore, we identified an even stronger coupling between the two aromatics, β2Y97 and β2F200, and for the first time provided direct evidence for the involvement of β2Y97 and β2F200 in GABA binding. As these residues are tightly linked, and mutation of either has similar, severe effects on GABA binding and receptor kinetics, we believe they form a single functional unit that may directly coordinate GABA

    Market Efficiency of Hessian Cloth and Sacking Bags’ Transferable Specific Delivery Contract transactions in a Regional Commodity Exchange in West Bengal, India

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    The price stabilization function of the commodity futures market is conditioned upon the efficiency of the market. An attempt has been made in this paper to test the efficiency of the hessian cloth and sacking bags’ contracts transactions in the East India Jute and Hessian Commodity Exchange - the oldest commodity-specific regional exchange in India - so as to gauge its contribution in the economically significant roles of price stabilization and price discovery in the underlying commodity spot market. Empirical results, based on the Johansen cointegration test, suggested that most of the hessian and sacking bags’ contracts were inefficient in the long run. In the short run, the sacking bags’ forward market exhibited short-run inefficiencies and pricing biases. However, large positive deviations from the co-integrating relation between the forward and spot prices of hessian cloth contracts were significantly corrected in the following period in the forward market. Therefore, the paper concludes, hessian forward contracts are relatively more efficient as compared to sacking bags’ contracts.Keywords: Market efficiency, East India Jute and Hessian Commodity Exchange, Hessian, Sacking, Cointegration test, Vector Error Correction.JEL classification: C58, G13, G14, P22

    Ultraviolet emission lines of Si II in quasars --- investigating the "Si II disaster"

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    The observed line intensity ratios of the Si II 1263 and 1307 \AA\ multiplets to that of Si II 1814\,\AA\ in the broad line region of quasars are both an order of magnitude larger than the theoretical values. This was first pointed out by Baldwin et al. (1996), who termed it the "Si II disaster", and it has remained unresolved. We investigate the problem in the light of newly-published atomic data for Si II. Specifically, we perform broad line region calculations using several different atomic datasets within the CLOUDY modeling code under optically thick quasar cloud conditions. In addition, we test for selective pumping by the source photons or intrinsic galactic reddening as possible causes for the discrepancy, and also consider blending with other species. However, we find that none of the options investigated resolves the Si II disaster, with the potential exception of microturbulent velocity broadening and line blending. We find that a larger microturbulent velocity (500kms1\sim 500 \rm \, kms^{-1}) may solve the Si II disaster through continuum pumping and other effects. The CLOUDY models indicate strong blending of the Si II 1307 \AA\ multiplet with emission lines of O I, although the predicted degree of blending is incompatible with the observed 1263/1307 intensity ratios. Clearly, more work is required on the quasar modelling of not just the Si II lines but also nearby transitions (in particular those of O I) to fully investigate if blending may be responsible for the Si II disaster.Comment: Accepted for publication in Ap

    Sustained drug release from multi-layered sequentially crosslinked electrospun gelatin nanofiber mesh

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    The aim of this study is to develop electrospun gelatin nanofibers based drug delivery carrier to achieve controlled and sustainable release of hydrophobic drug (piperine) for prolonged time. To accomplish this, we devised some strategies such as sandwiching the drug loaded gelatin nanofiber mesh with another gelatin nanofiber matrix without drug (acting as diffusion barrier), sequential crosslinking and finally, a combination of both. As fabricated multilayered electrospun nanofibers mesh was first characterized in terms of degradation study, morphology, drug-polymer interactions, thermal stability followed by studying their release kinetics in different physiological pH as per the gastrointestinal tract. Our results show that with optimized diffusional barrier support and sequential crosslinking together, a zero order sustained drug release up to 48 h may be achieved with a flexibility to vary the drug loading as per the therapeutic requirements. This work lays out the possibility of systematic design of multilayer nano-fiber mesh of a biopolymer as a drug delivery vehicle for hydrophobic drugs with a desired signature of zero order release for prolonged duration

    Pasture Larval Burden in a Grazing Land of Subtropical Hill Region of Meghalaya

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    Gastrointestinal (GI) helminths infections are considered as one of the most devastating diseases of livestock as it causes mortality, morbidity and thereby economic losses to the livestock owners. Infective larvae of nematodes are the source of infection to the livestock and one of the ways of nematode infection to the livestock is the ingestion of infective larvae (L3) through contaminated pasture. The count of infective larvae could give an idea of infection in animals grazed in a particular pasture land. Management of pasture is an important component of nematode parasite control programs. In the present study, pasture larval burden (PLB) of nematodes in a grazing pasture land of goats of a subtropical hill region of RiBhoi district of Meghalaya has been worked out during the year 2012-13, as such type of study has not yet been done earlier in this region

    Experimental Realization of an Exact Solution to the Vlasov Equations for an Expanding Plasma

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    We study the expansion of ultracold neutral plasmas in the regime in which inelastic collisions are negligible. The plasma expands due to the thermal pressure of the electrons, and for an initial spherically symmetric Gaussian density profle, the expansion is self-similar. Measurements of the plasma size and ion kinetic energy using fluorescence imaging and spectroscopy show that the expansion follows an analytic solution of the Vlasov equations for an adiabatically expanding plasma.Comment: 4 pages, 4 figure