4,260 research outputs found
Rearing of \u3ci\u3eScolytus Multistraiatus\u3c/i\u3e (Marsham) (Scolytidae: Coleoptera) for Toxicological Experiments
(excerpt)
In a study of the oral and contact toxicity of methoxychlor residues to the smaller European elm bark beetle, S, multistriatus, it is essential to have beetle material available which is of uniform physiological condition and age (Riedl, 197 3). Several rearing containers for bark beetles have been described in the literature (Clark and Osgood, 1964; Fox, 1958; Germain and Wygant, 1967; Schmitz, 1972). A common problem in such containers appears to be fungus growth on the logs due to insufficient ventilation and high humidity. Although these environmental conditions might not cause high mortality, they can render emerging beetles unsuitable for bioassays. In order to guarantee fresh beetle material of uniform age newly emerged beetles must be extracted immediately. This paper describes emergence drums with a ventilation system that prevents fungus growth. Also described is an efficient extraction device which prevented the insect from moving back into the rearing container once it reached the collecting apparatus
Aspects of the Feeding Behavior of \u3ci\u3eScolytus Multistriatus\u3c/i\u3e (Marsham) (Scoltytidae: Coleoptera) and Implications for Control
(excerpt)
Successful protection of elm trees can only be accomplished by means of thorough understanding of the feeding behavior of the smaller European elm bark beetle, Scolytus multistriatus (Marsham). Wolfenbarger and Buchanan (1939) and Whitten (1958) noted that most feeding occurred in the outer portion of the upper crown region, but offered no quantitative data. Therefore, this study was initiated to investigate the regional distribution of feeding injuries along a vertical and horizontal gradient in native American elm, Ulmus americana L
Culture Techniques for Rearing Soil Anthropods
Excerpt: Interest in soil biology has been prompted by recent investigations into the action of insecticides on plants and animals. Observations in the field must be supplemented by laboratory investigations conducted under controlled conditions. Consequently, it becomes necessary to rear and handle soil animals under artificial situations for bio-assay and life cycle studies. When large numbers of individuals are required, special problems in maintenance and manipulation arise. Relatively inexpensive and simple methods for such projects are essential and this paper describes some of those techniques which we have found expedient
Stability of the proton-to-electron mass ratio
We report a limit on the fractional temporal variation of the
proton-to-electron mass ratio as, obtained by comparing the frequency of a
rovibrational transition in SF6 with the fundamental hyperfine transition in
Cs. The SF6 transition was accessed using a CO2 laser to interrogate spatial
2-photon Ramsey fringes. The atomic transition was accessed using a primary
standard controlled with a Cs fountain. This result is direct and model-free
Adenovirus flow in host cell networks
Viruses are obligatory parasites that take advantage of intracellular niches to replicate. During infection, their genomes are carried in capsids across the membranes of host cells to sites of virion production by exploiting cellular behaviour and resources to guide and achieve all aspects of delivery and the downstream virus manufacturing process. Successful entry hinges on execution of a precisely tuned viral uncoating program where incoming capsids disassemble in consecutive steps to ensure that genomes are released at the right time, and in the right place for replication to occur. Each step of disassembly is cell-assisted, involving individual pathways that transmit signals to regulate discrete functions, but at the same time, these signalling pathways are organized into larger networks, which communicate back and forth in complex ways in response to the presence of virus. In this review, we consider the elegant strategy by which adenoviruses (AdVs) target and navigate cellular networks to initiate the production of progeny virions. There are many remarkable aspects about the AdV entry program; for example, the virus gains targeted control of a large well-defined local network neighbourhood by coupling several interacting processes (including endocytosis, autophagy and microtubule trafficking) around a collective reference state centred on the interactional topology and multifunctional nature of protein VI. Understanding the network targeting activity of protein VI, as well as other built-in mechanisms that allow AdV particles to be efficient at navigating the subsystems of the cell, can be used to improve viral vectors, but also has potential to be incorporated for use in entirely novel delivery systems.Peer reviewe
Preliminary analysis of a wake trailing a spacecraft
Using void regions trailing orbiting bodies to conserve propellant of untethered modules flying in formation with mother spacecraf
Thermo-Electric Properties of Quantum Point Contacts
I. Introduction
II. Theoretical background (Landauer-Buttiker formalism of
thermo-electricity, Quantum point contacts as ideal electron waveguides,
Saddle-shaped potential)
III. Experiments (Thermopower, Thermal conductance, Peltier effect)
IV. ConclusionsComment: #4 of a series of 4 legacy reviews on QPC'
An Efficient Pseudospectral Method for the Computation of the Self-force on a Charged Particle: Circular Geodesics around a Schwarzschild Black Hole
The description of the inspiral of a stellar-mass compact object into a
massive black hole sitting at a galactic centre is a problem of major relevance
for the future space-based gravitational-wave observatory LISA (Laser
Interferometer Space Antenna), as the signals from these systems will be buried
in the data stream and accurate gravitational-wave templates will be needed to
extract them. The main difficulty in describing these systems lies in the
estimation of the gravitational effects of the stellar-mass compact object on
his own trajectory around the massive black hole, which can be modeled as the
action of a local force, the self-force. In this paper, we present a new
time-domain numerical method for the computation of the self-force in a
simplified model consisting of a charged scalar particle orbiting a nonrotating
black hole. We use a multi-domain framework in such a way that the particle is
located at the interface between two domains so that the presence of the
particle and its physical effects appear only through appropriate boundary
conditions. In this way we eliminate completely the presence of a small length
scale associated with the need of resolving the particle. This technique also
avoids the problems associated with the impact of a low differentiability of
the solution in the accuracy of the numerical computations. The spatial
discretization of the field equations is done by using the pseudospectral
collocation method and the time evolution, based on the method of lines, uses a
Runge-Kutta solver. We show how this special framework can provide very
efficient and accurate computations in the time domain, which makes the
technique amenable for the intensive computations required in the
astrophysically-relevant scenarios for LISA.Comment: 15 pages, 9 figures, Revtex 4. Minor changes to match published
versio
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