10,004 research outputs found
Status and Management of Pyrethroid Resistance in the Predatory Mite, \u3ci\u3eAmblyseius Fallacis\u3c/i\u3e (Acarina: Phytoseiidae)
Low levels of (5-15 fold) resistance to synthetic pyrethroid (SP) insecticides occur in unexposed apple orchard populations of the predatory mite, Amblyseius fallacis Garman. Permethrin resistance in one strain has been elevated 60--500 fold by selections in green- houses. Multiple resistances to DDT and azinphosmethyl are present and cross-resistance to SP-related compounds is generic at 10--250 fold. Permethrin resistance appears due to both hydrolytic esterase and knock down resistance mechanisms. Permethrin resistance appears to be polygenic and more recessive than dominant; it is unstable in the presence of high densities of susceptible immigrant types, but is reasonably stable in the presence of unselected, resistant immigrant types. Successful establishment of SP-resistant mites into SP-treated, commercial apple orchards was monitored using electrophoretic finger-printing techniques over a two year period. Aspects of management of resistance in A. fallacis to improve IPM are discussed
Radio frequency science considerations
Use of the 400 MHz telecommunications system to obtain scientific information, to provide backup information for the experiments flown, and to obtain measurements which aid in designing future probes is considered. Recommended objectives of such a program are summarized and include: measure 400 MHz amplitude to determine adsorption and perhaps scintillation (if data rate permits); measure noise strength near 400 MHz to reexamine 400 MHz choice and to observe thermal, cosmic, and local synchrotron noise trends; probe VSWR sensing to monitor integrity of system, icing, and possible plasma effects; after the probe is finished, have the bus radio occultation in the same region where the probe fell to evaluate the occultation
First Year Computer Science Projects at Coventry University:Activity-led integrative team projects with continuous assessment.
We describe the group projects undertaken by first year undergraduate
Computer Science students at Coventry University. These are integrative course
projects: designed to bring together the topics from the various modules
students take, to apply them as a coherent whole. They follow an activity-led
approach, with students given a loose brief and a lot of freedom in how to
develop their project.
We outline the new regulations at Coventry University which eases the use of
such integrative projects. We then describe our continuous assessment approach:
where students earn a weekly mark by demonstrating progress to a teacher as an
open presentation to the class. It involves a degree of self and peer
assessment and allows for an assessment of group work that is both fair, and
seen to be fair. It builds attendance, self-study / continuous engagement
habits, public speaking / presentation skills, and rewards group members for
making meaningful individual contributions.Comment: 4 pages. Accepted for presentation at CEP2
Corotation of an intermittent solar wind source
The measured electron content of the solar wind in mid-1970 exhibited a region of relatively high electron density that reappeared at intervals of about 27.8 days. It is shown that the repeating event cannot be reconciled with the concept of a long-enduring steady flow, even though the recurrence period is close to the rotation period of the sun. This evidence of transients is inferred from the short duration of each appearance of the interval of higher density; each should last for roughly one corotation interval if it is caused by a steady stream. The radio path was approximately 0.8 AU long, and the corotation interval exceeded 3 days. Other aspects of the content data patterns support the view that such transient events are common in the solar wind. The mid-1970 repeating event is an unusually good example of the intermittent character of flow regions in the solar wind that fluctuate on a time scale of days but endure as identifiable regions for many months. A sputtering corotating source of thin solar plasma streams could explain this series of events; it could also be explained in terms of a stream that is steady in density and speed but undulating north-south so that it passes into and out of the 0.8 AU radio path in a matter of a day or less
Reduction and analysis of two sets of electron content measurements permitting the inference of electron density in the solar wind Final report
Reduction and analysis of electron content measurements permitting inference of electron density in solar win
The Correlation Function of Rich Clusters of Galaxies in CDM-like Models
We use ensembles of high-resolution CDM simulations to investigate the shape
and amplitude of the two point correlation function of rich clusters. The
standard scale-invariant CDM model with provides a poor description
of the clustering measured from the APM rich cluster redshift survey, which is
better fitted by models with more power at large scales. The amplitudes of the
rich cluster correlation functions measured from our models depend weakly on
cluster richness. Analytic calculations of the clustering of peaks in a
Gaussian density field overestimate the amplitude of the N-body cluster
correlation functions, but reproduce qualitatively the weak trend with cluster
richness. Our results suggest that the high amplitude measured for the
correlation function of richness class Abell clusters is either an
artefact arising from incompleteness in the Abell catalogue, or an indication
that the density perturbations in the early universe were very non-Gaussian.Comment: uuencoded compressed postscript ,MNRAS, in press, OUAST-93-1
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