Simultaneous Parasitism of Field-Collected Green Cloverworm, \u3ci\u3eHypena Scabra\u3c/i\u3e (Lepidoptera: Noctuidae) Larvae by Endoparasitioids and an Entomopathogenic Fungus

The impacts of entomopathogens (e.g., fungi, bacteria, protists and viruses) on larval Lepidoptera and their associated insect parasitoids have been examined in laboratory studies but field studies of interaction between these two mortality factors are rare. We present field observations of concurrent insect parasitism and fungal disease infection in larvae of the green cloverworm, Hypena scabra, a sporadic pest of soybean (Glycine max) in North America. We reared ten parasitoid species from H. scabra larvae during our three-month study. Three parasitoid species were dominant and overlapped the period of infection by the entomopathogenic fungus Nomuraea rileyi: Aleiodes nolophanae, Cotesia plathypenae and Campylochaeta plathypenae. Two of the three parasitoid species, Co. plathypenae and Ca. plathypenae, completed development within H. scabra larvae infected by N. rileyi. Overall incidence of simultaneous parasitism and fungal infection was low, averaging 6.7% of H. scabra larvae parasitized by Ca. plathypenae and 3.3% of those parasitized by Co. plathypenae

Vortex Fluctuations in the Critical Casimir Effect of Superfluid and Superconducting Films

Vortex-loop renormalization techniques are used to calculate the magnitude of the critical Casimir forces in superfluid films. The force is found to become appreciable when size of the thermal vortex loops is comparable to the film thickness, and the results for T < Tc are found to match very well with perturbative renormalization theories that have only been carried out for T > Tc. When applied to a high-Tc superconducting film connected to a bulk sample, the Casimir force causes a voltage difference to appear between the film and bulk, and estimates show that this may be readily measurable.Comment: 4 pages, 5 figures, Revtex 4, typo correctio

The walking robot project

A walking robot was designed, analyzed, and tested as an intelligent, mobile, and a terrain adaptive system. The robot's design was an application of existing technologies. The design of the six legs modified and combines well understood mechanisms and was optimized for performance, flexibility, and simplicity. The body design incorporated two tripods for walking stability and ease of turning. The electrical hardware design used modularity and distributed processing to drive the motors. The software design used feedback to coordinate the system and simple keystrokes to give commands. The walking machine can be easily adapted to hostile environments such as high radiation zones and alien terrain. The primary goal of the leg design was to create a leg capable of supporting a robot's body and electrical hardware while walking or performing desired tasks, namely those required for planetary exploration. The leg designers intent was to study the maximum amount of flexibility and maneuverability achievable by the simplest and lightest leg design. The main constraints for the leg design were leg kinematics, ease of assembly, degrees of freedom, number of motors, overall size, and weight

Space Laser Power Transmission System Studies

Power transmission by laser technique is addressed. Space to Earth and space to space configurations are considered

Non-equilibrium umbrella sampling applied to force spectroscopy of soft matter

Physical systems often respond on a timescale which is longer than that of the measurement. This is particularly true in soft matter where direct experimental measurement, for example in force spectroscopy, drives the soft system out of equilibrium and provides a non-equilibrium measure. Here we demonstrate experimentally for the first time that equilibrium physical quantities (such as the mean square displacement) can be obtained from non-equilibrium measurements via umbrella sampling. Our model experimental system is a bead fluctuating in a time-varying optical trap. We also show this for simulated force spectroscopy on a complex soft molecule--a piston-rotaxane

Coupling of phonons to a helium atom adsorbed on graphite

We compute the self-energy for a ^4He atom adsorbed on graphite to second order in the phonon coupling. The phonon contributions amount to several degrees Kelvin. The imaginary part corresponds to a lifetime of some 10^(-11) s