1,875 research outputs found
Designing fuzzy rule based classifier using self-organizing feature map for analysis of multispectral satellite images
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
Ultraviolet emission lines of Si II in quasars --- investigating the "Si II disaster"
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 () 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
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
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
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
Electron Temperature Evolution in Expanding Ultracold Neutral Plasmas
We have used the free expansion of ultracold neutral plasmas as a
time-resolved probe of electron temperature. A combination of experimental
measurements of the ion expansion velocity and numerical simulations
characterize the crossover from an elastic-collision regime at low initial
Gamma_e, which is dominated by adiabatic cooling of the electrons, to the
regime of high Gamma_e in which inelastic processes drastically heat the
electrons. We identify the time scales and relative contributions of various
processes, and experimentally show the importance of radiative decay and
disorder-induced electron heating for the first time in ultracold neutral
plasmas
- …