Towards Integrated Protection from the Southern Pine Beetle

Current southern pine beetle ( Dendroctonus frontalis Zimm.) control depends heavily upon direct approaches having short-term payoffs. Chemical or physical tactics have fidled to check epidemics in the Gulf South. A major challenge lies in developing and using indirect methods for managing this pest. Promotion of stand resistance and biotic agents, and manipulation of stand density and cutting practices, hold prospect for reducing the incidence and severity of beetle-caused losses

Benchmarking of a 1D Scrape-off layer code SOLF1D with SOLPS and its use in modelling long-legged divertors

A 1D code modelling SOL transport parallel to the magnetic field (SOLF1D) is benchmarked with 2D simulations of MAST-U SOL performed via the SOLPS code for two different collisionalities. Based on this comparison, SOLF1D is then used to model the effects of divertor leg stretching in 1D, in support of the planned Super-X divertor on MAST. The aim is to separate magnetic flux expansion from volumetric power losses due to recycling neutrals by stretching the divertor leg either vertically or radially.Comment: 31 pages, 17 figures. This is an author-created, un-copyedited version of an article accepted for publication in Plasma Physics and Controlled Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

Endoparasitic Nematodes of Ips Bark Beetles in Eastern Texas

East Texas Ips species contained 4 specific internal nematodes; I. avulsus (Eichhoff) were infected with Parasitylenchus avulsi Massey, I. grandicollis (Eichhoff) with Contortylenchus grandicolli (Massey) Rlihm, and I. calligraphus (Germar) with Contortylenchus elongatus (Massey) Nickle and Parasitaphelenchus sp. In all 3 bark beetles, infection peaked in July and August when 50-58% of adults from naturally attacked pine trees contained nematodes. Infection levels declined to 20-30% during January and February. Infected I. grandicollis and I. avulsus adults appeared lighter in color than noninfected adults. Nematode infection apparently delayed emergence of both sexes of I. grandicollis and females of I. avulsus. In I. grandicollis, nematode infection did not affect ability to construct egg galleries or number of offspring produced. Supercooling temperatures for infected I. grandicollis and I. calligraphus were no different than those of noninfected beetles

Effects of Feeding and Mating on Pheromone Release in the Southern Pine Beetle

Response of field populations of Delldroetoll1lS frontalis Zimmermann to their aggregating pheromone was correlated with pheromone content of dissectted hindgut tissues of adult beetles a determined by the gas-liquid chromatography (GLC) technique. Adult beetles in various stages of feeding activity and reproductive states were used for this purpose. Two major components of the aggregating pheromones, frontalin and trans-verbenol, were found in the largest quantities in emergent unfed females. After 48 hours of feeding, frontal in content of the hindguts was 29% and trans-verbeno content was only 5% of that of emergent females. Continuous bioassays of females feeding in host material showed increasing response of field populations to the beetle until 24-48 hours after feeding had begun, then response declined. The fact that pheromone content declined steadily following beetle attack while field response increased was thought to be due to capture of the pheromone in frass particles, thus slowing its rate of release. The decline of pheromone components in hindguts of mated females was not precipitous or abrupt a suggested by behavioral studies on other species of DendroctollllS. Field bioassays confirmed the GLC studies and showed that in both virgin and mated females peak attractiveness occurred 24-48 hours after the tree was attacked the beetles

Distribution of Some Predators and Parasites of the Southern Pine Beetle in Two Species of Pine

Southern pine beetle, Dendroctonus frontalis Zimmerman, and its natural insect enemies were reared from infested loblolly pines, Pinus taeda L., and shortleaf pines, P. echinata Mill. Southern pine beetle broods were most dense during spring (Mar.-May) and least dense in late summer. Populations were higher in late winter than in midsummer. There were no differences in beetle densities between the pine species. Twelve predators and 9 parasites comprised ca. 99% of the natural enemy complex. Total density of the 12 predators did not vary with either season or tree species. Total parasite density, however, was highest in midsummer, lowest in late winter, and was significantly higher in shortleaf pine. Species diversity of predators and parasites was highest during spring and summer seasons and varied significantly between tree species

Nuclear binding energies: Global collective structure and local shell-model correlations

Nuclear binding energies and two-neutron separation energies are analyzed starting from the liquid-drop model and the nuclear shell model in order to describe the global trends of the above observables. We subsequently concentrate on the Interacting Boson Model (IBM) and discuss a new method in order to provide a consistent description of both, ground-state and excited-state properties. We address the artefacts that appear when crossing mid-shell using the IBM formulation and perform detailed numerical calculations for nuclei situated in the 50-82 shell. We also concentrate on local deviations from the above global trends in binding energy and two-neutron separation energies that appear in the neutron-deficient Pb region. We address possible effects on the binding energy, caused by mixing of low-lying $0^{+}$ intruder states into the ground state, using configuration mixing in the IBM framework. We also study ground-state properties using a deformed mean-field approach. Detailed comparisons with recent experimental data in the Pb region are amply discussed.Comment: 69 pages, TeX (ReVTeX). 23 eps figures. 1 table. Modified version. Accepted in Nucl. Phys.