742 research outputs found
Research Notes : United States : Screening for cytoplasmic/maternal effects in resistance to soybean cyst nematode
With the discovery of soybean cyst nematode (SCN) in the U.S. in 1954, the research for resistance was initiated. Ross and Brim (1957) identified several soybean plant introductions resistant to the North Carolina SCN populations. Epps and Hartwig (1972) reported PI lines resistant to race 4
QoS Constrained Optimal Sink and Relay Placement in Planned Wireless Sensor Networks
We are given a set of sensors at given locations, a set of potential
locations for placing base stations (BSs, or sinks), and another set of
potential locations for placing wireless relay nodes. There is a cost for
placing a BS and a cost for placing a relay. The problem we consider is to
select a set of BS locations, a set of relay locations, and an association of
sensor nodes with the selected BS locations, so that number of hops in the path
from each sensor to its BS is bounded by hmax, and among all such feasible
networks, the cost of the selected network is the minimum. The hop count bound
suffices to ensure a certain probability of the data being delivered to the BS
within a given maximum delay under a light traffic model. We observe that the
problem is NP-Hard, and is hard to even approximate within a constant factor.
For this problem, we propose a polynomial time approximation algorithm
(SmartSelect) based on a relay placement algorithm proposed in our earlier
work, along with a modification of the greedy algorithm for weighted set cover.
We have analyzed the worst case approximation guarantee for this algorithm. We
have also proposed a polynomial time heuristic to improve upon the solution
provided by SmartSelect. Our numerical results demonstrate that the algorithms
provide good quality solutions using very little computation time in various
randomly generated network scenarios
Observed Inter annual Variability of Upwelling Characteristics during 2016 2017 A Study using Princeton Ocean Model
Oceanographic observations carried out during 2016 and 2017 onboard INS Sagardhwani in the Southeastern Arabian sea are used to study the inter-annual variability of the upwelling. In 2016, the strong upwelling signatures are noticed in the observations (SST < 27°C and strong up-slopping of isotherms) as well as in the satellite derived sea level anomaly data. Whereas in 2017 the low sea level in June (-2 cm) are weakened during the mid of July (+3 cm) along the southern track (8 °N and 9 °N). This decrease in the strength in 2017 can be attributed to two major reasons. One is the presence of an anti-cyclonic eddy along the coast (8.5 °N, 76.5 °E) weakens the upwelling processes and second is the weak northerly component of the wind compared to 2016. In addition, Lakshadweep low is less prominent and situated towards the southern side (around 7°N) of its usual region of occurrence in 2017. The inter-annual variability of upwelling during July 2016 and 2017 is investigated using the 3D ocean model Princeton Ocean Model. Experiments with model in different combinations of forcing reveals that the alongshore wind component is the major parameter influencing the upwelling characteristics during these periods
Recovery of metal values from copper converter and smelter slags by ferric chloride leaching
A study of the recovery of copper, nickel and cobalt from copper converter and smelter slags by leaching with ferric chloride is reported. The converter slag from Ghatsila, India contained 4.03% copper, 1.99% nickel and 0.48% cobalt and the smelter slag contained 1.76% copper, 0.23% nickel and 0.19% cobalt. Various parameters including the effect of stirring, leaching time, leaching temperature, concentration of ferric chloride, solid-liquid ratio and particle size, on the extraction of copper, nickel and cobalt have been studied. 92% copper, 28% nickel and 24% cobalt could be extracted from converter slag under optimum conditions, whereas 54% copper, 71% nickel and 44% cobalt could be extracted from smelter slag
Research Notes : United States : An improved greenhouse method of evaluation for inheritance of resistance to race 4 of soybean cyst nematode
Studies to determine mode of inheritance of resistance to soybean cyst nematode (SCN), Heterodera glycines, could be influenced by the methods of evaluation in use. Any improvement in growing conditions of the host and pathogen, superior inoculation techniques, inducement of desirable infection in the host with minimum genetic variability in the SCN population could result in optimum expression of full complement of genes conferring resistance to SCN races. Our objective was to determine the mode of inheritance of resistance in Soybean Plant Introduction PI 88.788 for SCN race 4 reaction, using the improved techniques of evaluation
Electrical and Magnetic behaviour of PrFeAsO0.8F0.2 superconductor
The superconducting and ground state samples of PrFeAsO0.8F0.2 and PrFeAsO
have been synthesised via easy and versatile single step solid state reaction
route. X-ray & Reitveld refine parameters of the synthesised samples are in
good agreement to the earlier reported value of the structure. The ground state
of the pristine compound (PrFeAsO) exhibited a metallic like step in
resistivity below 150K followed by another step at 12K. The former is
associated with the spin density wave (SDW) like ordering of Fe spins and later
to the anomalous magnetic ordering for Pr moments. Both the resistivity
anomalies are absent in case of superconducting PrFeAsO0.8F0.2 sample. Detailed
high field (up to 12Tesla) electrical and magnetization measurements are
carried out for superconducting PrFeAsO0.8F0.2 sample. The PrFeAsO0.8F0.2
exhibited superconducting onset (Tconset) at around 47K with Tc({\rho} =0) at
38K. Though the Tconset remains nearly invariant, the Tc({\rho} =0) is
decreased with applied field, and the same is around 23K under applied field of
12Tesla. The upper critical field (Hc2) is estimated from the Ginzburg Landau
equation (GL) fitting, which is found to be ~ 182Tesla. Critical current
density (Jc) being calculated from high field isothermal magnetization (MH)
loops with the help of Beans critical state model, is found to be of the order
of 103 A/cm2. Summarily, the superconductivity characterization of single step
synthesised PrFeAsO0.8F0.2 superconductor is presented.Comment: 15 Pages Text + Fig
Effect of Azimuthal Asymmetry Caused by Upwelling on 3D Ocean Acoustic Propagation
3-D underwater parabolic equation model based on implicit finite difference method has been implemented for South Eastern Arabian Sea (SEAS). The bathymetric and geo-acoustic features have been integrated in the model for a 50 km circular region in SEAS. The model can simulate the effects of azimuthal variation in oceanographic features and compute azimuthally coupled pressure due to an omni-directional source. The azimuthal variation in oceanographic conditions can be observed during an upwelling event. In the first case study, the effect of upwelling event on three-dimensional acoustic propagation has been studied by using sound speed profile data derived from INS Sagardhwani observations. The difference in Transmission loss mosaic for upslope and downslope propagation is due to bathymetry as well as upwelling. In the second case study, the effect of upwelling only, is studied by running a model corresponding to range independent sound speed profile field and range dependent bathymetry. It was observed that during this upwelling event, the transmission loss is higher at longer ranges during upslope propagation than downslope propagation. This is due to the increase in the thickness of sonic layer duct as acoustic wave propagates from shallow to deep water. The effect of azimuthal variation
Assessing the Impacts of Climate Change on Crop Yields in Different Agro-climatic Zones of India
The study attempts to estimate and predict climate impact on crop yields using future temperature projections under two climate emissions scenarios of RCP 4.5 and 8.5 for three different time periods (2030s, 2050s and 2080s) across Agro-climatic zones (ACZ) of India. During the period 1966-2011, a significant rise was observed in both the annual mean maximum and minimum temperature across ACZs. Rainfall recorded an annual decline in Himalayan Regions and Gangetic Plains and a rise in Coastal Regions, Plateau & Hills and Western Dry Region. Our results showed high heterogeneity in climate impact on kharif and rabi crop yields (with both negative and positive estimates) across ACZs. It was found that rainfall had a positive effect on most of crop yields, but was not sufficient enough to counterbalance the impact of temperature. Changes in crop yield were more pronounced for higher emission scenario of RCP 8.5. Thus, it was evident that the relative impacts of climate change and the associated vulnerability vary by ACZs, hence comprehensive crop and region-specific adaptation measures should be emphasized that helps in enhancing resilience of agricultural system in short to medium term
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