429 research outputs found
Exploration of Antiviral Effects of RNA-dependent RNA Polymerases 3, 4 and 5 in Arabidopsis.
Small RNAs play a number of vital roles in plants, including viral resistance. A particular class of small RNA that regulates plant defense from pathogens, among other functions, is known as small interfering RNAs (siRNAs). A key player in the biogenesis pathway of siRNAs are RNA-Dependent RNA Polymerases (RDRs). There are six RDR proteins in Arabidopsis thaliana, three of which have well documented roles (RDRs 1, 2 and 6), and three of which have no documented role. Here, we look at the functions of the unstudied RDRs, RDRs 3, 4 and 5, to see whether they affect antiviral resistance
Determinants of rapid response success for alien invasive species in aquatic ecosystems
Alien invasive species (AIS) have received much attention for their harmful effects on health, ecology and the economy. Although the best approach is prevention of introductions, it is imperative that rapid response (RR) countermeasures be available, should prevention fail. I analyzed 127 cases involving RR to AIS in aquatic systems. Results indicated the rate of eradication success was greater, and slightly higher, for plant versus animal AIS, and when chemical versus mechanical methods were used, respectively, but was unaffected by habitat size. Suppression of AIS was most successful in small habitats and with chemical versus mechanical methods, but was unaffected by taxonomy (plant or animal). Outcome was not affected by the population size, project duration, ecosystem (marine or freshwater), or number (single or multiple) of methods used. Managers should expect that different factors will affect success depending on whether intervention aims for complete elimination or population reduction of AIS
Metal accumulation in Paradiplozoon ichthyoxanthon Avenant-Oldewage, 2013 infecting Labeobarbus aeneus (Burchell, 1822); ecological and species level perspectives
Abstract: Please refer to full text to view abstract.Ph.D. (Zoology
Simulant Development for Hanford Tank Farms Double Valve Isolation (DVI) Valves Testing
Leakage testing of a representative sample of the safety-significant isolation valves for Double Valve Isolation (DVI) in an environment that simulates the abrasive characteristics of the Hanford Tank Farms Waste Transfer System during waste feed delivery to the Waste Treatment and Immobilization Plant (WTP) is to be conducted. The testing will consist of periodic leak performed on the DVI valves after prescribed numbers of valve cycles (open and close) in a simulated environment representative of the abrasive properties of the waste and the Waste Transfer System. The valve operations include exposure to cycling conditions that include gravity drain and flush operation following slurry transfer. The simulant test will establish the performance characteristics and verify compliance with the Documented Safety Analysis. Proper simulant development is essential to ensure that the critical process streams characteristics are represented, National Research Council report “Advice on the Department of Energy's Cleanup Technology Roadmap: Gaps and Bridges
Transmission and Incidence Losses for a Slotted Plate
The objective of this work is to find a model of the stagnation pressure loss resulting from flow through a slotted plate, which is effectively a cascade of flat plate airfoils, particularly at very large angles of incidence. Data from a published experiment is examined, and compared with control volume analysis, and CFD code calculations. An assumption that the loss can be separated into a transmission loss and an incidence loss seems to be justified by the data. Both the data and the CFD code results are consistent with an incidence loss model in which the flow component normal to the slot axis is lost. However, the experimental transmission loss is much larger than calculated values
The use of weak waves as diagnostic tracers in unsteady flows
Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.This paper examines the tracing of the trajectories of weak waves behind a shock wave induced flow in order to establish how the domain shape influences the flow both from a spatial and temporal perspective. The basic principle is that if a particle produces a series of point disturbances in a flow field the perturbations induced will propagate outwards at the local sonic velocity whilst at the same time being convected along with the local flow velocity. A number of issues may be identified for an unsteady flow. Firstly the flow field at later times may be influenced by perturbations produced at earlier times. Secondly, if the positions of the perturbations can be monitored as a function of time then the trajectory and velocity of the particle may be deduced. Thirdly, if a perturbation arises from a point on a boundary then its influence, if any, on any particular part of the flow can be established.cs201
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