Ion-acoustic solitons in warm magnetoplasmas with super-thermal electrons

In this work, the phenomenon of formation of localised electrostatic waves (ESW) or soliton is considered in a warm magnetoplasma with the possibility of non-thermal electron distribution. The parameter regime considered here is relevant in case of magnetospheric plasmas. We show that deviation from a usual relaxed Maxwellian distribution of the electron population has a significant bearing in the allowed parameter regime, where these ESWs can be found. We further consider the presence of more than one electron temperature, which is inspired by recent space-based observations[key-2].Comment: 10 pages, 5 figure

AAUOKHYB -1 : An excellent Okra hybrid developed by Assam Agricultural University (AAU) suitable for diverse agro-climatic situation of North East India

A hybrid development programme on okra (Abelmoschus esculentus) was undertaken at the Assam Agricultural University (AAU), Jorhat. The work included collection and evaluation of okra germplasm, identification of parents for hybridization, selfing of identified parental lines, making crosses and production of hybrid seeds, testing of hybrids for yield and resistance to Yellow Vein Mosaic Virus (YVMV) disease, adaptability under diverse agro-climatic condition and testing in all India trials. The programme resulted in development and identification of excellent Okra hybrid AAUOKHYB-1 in 2017.  The performance of the hybrid was very good under diverse agro-climatic conditions yielding about 162.0 q/ha fruit yield which is 32.5% higher than the best commercial check Arka Anamika. The hybrid showed resistant (R) reaction to YVMV disease. A wide range of heterosis upto 43% was exhibited by the hybrid in different vegetable research centers of the country as compared to the best check variety

Characterization of mango (Mangifera indica L.) genotypes based on physio-chemical quality attributes

Evaluation of fruit crops has been successfully utilized for studying the performance of varieties under different agro climatic regions time to time. In the present study cultivars were characterized on the basis of their physico-biochemical attributes. “Mallika” and “Neelgoa” were found superior in terms of fruit weight (321.87 g), size (12.55 cm, 8.13 cm), pulp weight (257.91 g) and pulp stone ratio (7.71) respectively. “Mallika” excelled in terms of sugar (20.82), while “Amrapali” in carotenoids (8.38 mg/100 g). Among them, Mallika (22.41?B) possessed the high-est amount of total soluble solids while lowest amount in Langra (16.90 ?B) whereas maximum titrable. The study shows the potential of Amrapali in terms of its quality, being late can meet the demand for later period when no other cultivar is available

Impact of pruning on growth, yield and quality of mango cv. Dashehari

An experiment was carried out to study the impact of pruning on growth, yield and quality of mango cv. Dashehari. Ten treatments consisted of heading back of terminal shoots at two different levels viz., M1: 10 cm & M2: 20 cm, with two level of frequency i.e., F1: annually & F2: biennially and at two different timings i.e., T1: immediately after fruit harvest (June-July) & T2: during rest period before the emergence of new growth (floral and vegetative) including control as M0F0T0 with and without Paclobutazol (PBZ), were imposed on the trees. The trial was laid out in Randomized block design replicated thrice and single tree served as treatment unit. On the basis of 6 years (2009-2014) pooled data, it was observed that the vigorous growth in terms of tree height (4.56 m), trunk circumference (43.56 cm) and tree spread (3.03 m) were observed in the trees under control (M0F0T0 without PBZ), whereas the trees which were pruned annually by heading back of 20 cm of terminal shoots during rest period before emergence of new growth along with paclabutrazol application (M2F1T2) showed less growth in terms of tree height (3.30 m) and spread (2.21 m). The annual pruning of tree by heading back of 10 cm of terminal shoots immediately after fruit harvest along with paclobutrazol application (M1F1T1) proved effective for increasing the number of fruits per tree (51.31), yield (9.09 kg/tree and 15.14 t/ha), B: C ratio (4.04), maintaining fruit quality and for having the appropriate dwarfing effect on the tree

From Cluster to Grid: A Case Study in Scaling-Up a Molecular Electronics Simulation Code

This paper describes an ongoing project whose goal is to significantly improve the performance and applicability of a molecular electronics simulation code. The specific goals are to (1) increase computational performance on the simulation problems currently being solved by our physics collaborators; (2) allow much larger problems to be solved in reasonable time; and (3) expand the set of resources available to the code, from a single homogeneous cluster to a campus-wide computational grid, while maintaining acceptable performance across this larger set of resources. We describe the sequential performance of the code, the performance of two parallel versions, and the benefits of problem-specific load balancing strategies. The grid context motivates the need for runtime algorithm selection; we present a component-based software framework that makes this possible

Thermal instability of an expanding dusty plasma with equilibrium cooling

We present an analysis of radiation induced instabilities in an expanding plasma with considerable presence of dust particles and equilibrium cooling. We have shown that the equilibrium expansion and cooling destabilize the radiation condensation modes and the presence of dust particles enhances this effect. We have examined our results in the context of ionized, dusty-plasma environments such as those found in planetary nebulae (PNe). We show that due to the non-static equilibrium and finite equilibrium cooling, small-scale localized structures formed out of thermal instability, become transient, which agrees with the observational results. The dust-charge fluctuation is found to heavily suppress these instabilities, though in view of non-availability of convincing experimental data, a definitive conclusion could not be made.Comment: 23 pages, 14 figure

Temperature dependence of the resistance of metallic nanowires (diameter ≥\geq 15 nm): Applicability of Bloch-Gr\"{u}neisen theorem

We have measured the resistances (and resistivities) of Ag and Cu nanowires of diameters ranging from 15nm to 200nm in the temperature range 4.2K-300K with the specific aim to assess the applicability of the Bloch-Gr\"{u}neisen formula for electron phonon resistivity in these nanowires. The wires were grown within polymeric templates by electrodeposition. We find that in all the samples the resistance reaches a residual value at T=4.2K and the temperature dependence of resistance can be fitted to the Bloch-Gr\"{u}neisen formula in the entire temperature range with a well defined transport Debye temperature ($\Theta_{R}$). The value of Debye temperature obtained from the fits lie within 8% of the bulk value for Ag wires of diameter 15nm while for Cu nanowires of the same diameter the Debye temperature is significantly lesser than the bulk value. The electron-phonon coupling constants (measured by $\alpha_{el-ph}$ or $\alpha_{R}$) in the nanowires were found to have the same value as that of the bulk. The resistivities of the wires were seen to increase as the wire diameter was decreased. This increase in the resistivity of the wires may be attributed to surface scattering of conduction electrons. The specularity p was estimated to be about 0.5. The observed results allow us to obtain the resistivities exactly from the resistance and gives us a method of obtaining the exact numbers of wires within the measured array (grown within the template).Comment: 9 pages, 10 figure

Comparative performance of some popular ANN algorithms on benchmark and function approximation problems

We report an inter-comparison of some popular algorithms within the artificial neural network domain (viz., Local search algorithms, global search algorithms, higher order algorithms and the hybrid algorithms) by applying them to the standard benchmarking problems like the IRIS data, XOR/N-Bit parity and Two Spiral. Apart from giving a brief description of these algorithms, the results obtained for the above benchmark problems are presented in the paper. The results suggest that while Levenberg-Marquardt algorithm yields the lowest RMS error for the N-bit Parity and the Two Spiral problems, Higher Order Neurons algorithm gives the best results for the IRIS data problem. The best results for the XOR problem are obtained with the Neuro Fuzzy algorithm. The above algorithms were also applied for solving several regression problems such as cos(x) and a few special functions like the Gamma function, the complimentary Error function and the upper tail cumulative $\chi^2$-distribution function. The results of these regression problems indicate that, among all the ANN algorithms used in the present study, Levenberg-Marquardt algorithm yields the best results. Keeping in view the highly non-linear behaviour and the wide dynamic range of these functions, it is suggested that these functions can be also considered as standard benchmark problems for function approximation using artificial neural networks.Comment: 18 pages 5 figures. Accepted in Pramana- Journal of Physic

Performance of two Askaryan Radio Array stations and first results in the search for ultrahigh energy neutrinos

Ultrahigh energy neutrinos are interesting messenger particles since, if detected, they can transmit exclusive information about ultrahigh energy processes in the Universe. These particles, with energies above 1016 eV, interact very rarely. Therefore, detectors that instrument several gigatons of matter are needed to discover them. The ARA detector is currently being constructed at the South Pole. It is designed to use the Askaryan effect, the emission of radio waves from neutrino-induced cascades in the South Pole ice, to detect neutrino interactions at very high energies. With antennas distributed among 37 widely separated stations in the ice, such interactions can be observed in a volume of several hundred cubic kilometers. Currently three deep ARA stations are deployed in the ice, of which two have been taking data since the beginning of 2013. In this article, the ARA detector “as built” and calibrations are described. Data reduction methods used to distinguish the rare radio signals from overwhelming backgrounds of thermal and anthropogenic origin are presented. Using data from only two stations over a short exposure time of 10 months, a neutrino flux limit of 1.5 × 10−6 GeV=cm2=s=sr is calculated for a particle energy of 1018 eV, which offers promise for the full ARA detector