3,151 research outputs found
Turbulence and Mixing in the Intracluster Medium
The intracluster medium (ICM) is stably stratified in the hydrodynamic sense
with the entropy increasing outwards. However, thermal conduction along
magnetic field lines fundamentally changes the stability of the ICM, leading to
the "heat-flux buoyancy instability" when and the "magnetothermal
instability" when . The ICM is thus buoyantly unstable regardless of
the signs of and . On the other hand, these
temperature-gradient-driven instabilities saturate by reorienting the magnetic
field (perpendicular to when and parallel to when ), without generating sustained convection. We show that
after an anisotropically conducting plasma reaches this nonlinearly stable
magnetic configuration, it experiences a buoyant restoring force that resists
further distortions of the magnetic field. This restoring force is analogous to
the buoyant restoring force experienced by a stably stratified adiabatic
plasma. We argue that in order for a driving mechanism (e.g, galaxy motions or
cosmic-ray buoyancy) to overcome this restoring force and generate turbulence
in the ICM, the strength of the driving must exceed a threshold, corresponding
to turbulent velocities . For weaker driving, the ICM
remains in its nonlinearly stable magnetic configuration, and turbulent mixing
is effectively absent. We discuss the implications of these findings for the
turbulent diffusion of metals and heat in the ICM.Comment: 8 pages, 2 figs., submitted to the conference proceedings of "The
Monster's Fiery Breath;" a follow up of arXiv:0901.4786 focusing on the
general mixing properties of the IC
Analyses of Generic Dairy Advertising, 1984-97
Generic advertising raised fluid milk sales about 6.0 percent, or 18.1 billion pounds, between September 1984 and September 1997. Sales of cheese rose by about 6.8 billion pounds (milk equivalent) in the same period because of increased generic advertising. An assessment of 15 cents per hundredweight of milk sold commercially, mandated by the Dairy and Tobacco Adjustment Act of 1983, funded the advertising. Activities of the National Fluid Milk Processor Promotion Board also contributed to increased milk sales over the past year. Gross returns to dairy farmers between September 1984 and September 1997 were estimated to increase by $3.44 for each dollar spent on generic advertising.cheese, fluid milk, advertising, demand, entry, exit, distributed lag, econometrics, simulation, elasticities, Milk Processor Education Program, Livestock Production/Industries, Marketing,
A Robust Frame of WSN Utilizing Localization Technique
Wireless sensor networks are becoming increasingly popular due to their low cost and wide applicability to support a large number of diverse application areas. Localization of sensor nodes is a fundamental requirement that makes the sensor data meaningful. A wireless sensor network (WSN) consist of spatially distributed autonomous devices using sensors to monitor cooperatively physical or environmental conditions such as temperature, sound, vibration, pressure, motion or pollutants at different locations. The development of wireless sensor networks was originally motivated by a military application like battlefield surveillance. Node localization is required to report the origin of events, assist group querying of sensors, routing and to answer questions on the network coverage. So one of the fundamental challenges in wireless sensor network is node localization. This paper discusses different approaches of node localization discovery in wireless sensor networks. The overview of the schemes proposed by different scholars for the improvement of localization in wireless sensor networks is also presented. Keywords: Localization, Particle Swarm Optimization, Received Signal Strength, Angle of Arrival
Red palm weevil incidence: Spatial pattern and implications in technology adoption
Red palm weevil (RPW) is one of the major fatal pests of coconut. Conventional extension approaches need to be refined forachieving the desired outcome on adoption of integrated pest management (IPM) strategies against RPW, especially among smalland marginal farming communities. The pattern of incidence, severity of infestation and age of palms are the factors motivatingfarmers for adoption of IPM practices. Taking these into account, a technology delivery approach for RPW management wasevolved and implemented in the entire geographical extent of 520 ha area of Edava grama panchayat in Thiruvananthapuramdistrict of Kerala state, India. This approach involves farmer participatory surveillance and monitoring with technical facilitationfrom research institutions which is a paradigm shift to community based area wide management strategies. Besides holdings’profile, number of RPW infested/lost palms and GPS (i.e., latlong) coordinates of infested palms were recorded. The spatialdistribution pattern was analyzed using Indices of Dispersion (ID), Patchiness (IP) Cluster Frequency (ICF) and Mean Crowding(IMC) at different cluster levels (i.e., holdings, administrative segments and grids). ESRI GIS software was used to depict geospatialpatterns of RPW infestation. Among 5410 coconut holdings, 18.7 per cent were having RPW infested palms. The pest incidencein juvenile palms was significantly higher compared to adult palms. The distribution pattern of infested palms was observed to beaggregated. Knowledge level of farmers regarding aspects of pest and management was below 10 per cent. The proposedmethodology of participatory data documentation resulted in rapid and reliable collection of data from large area with an additionalbenefit of experiential learning for farmers in the locality
Phytochemical Investigation and Pharmocological Studies of the Flowers of \u3cem\u3ePithecellobium Dulce\u3c/em\u3e
To evaluate the effects from the fresh flowers of Pithecellobium dulce (Roxb.) Benth, belonging to the family of Leguminosae subfamily Mimosoideae, a glycoside quercitin has been isolated. The ethyl acetate soluble of P. dulce containing the above glycoside was studied both in silico and in vitro for the anti-inflammatory and anti-bacterial properties. The concatenation of the in silico and in vivo has been done. Results indicated the activity of this flavonol glycoside in the protection of HRBC lysis and against the gram positive micro organisms, thus confirming its anti-inflammatory and anti-bacterial properties
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