Relationship of Imported Fire Ant (Hymenoptera: Formicidae) Integument Coloration to Cuticular Hydrocarbon and Venom Alkaloid Profiles.

Red imported fire ant (Solenopsis invicta Buren; RIFA) and black imported fire ant (Solenopsis richteri Forel (Hymenoptera: Formicidae); BIFA) are considered distinct species with introgression via a reproductively functional hybrid (HIFA). The RIFA and BIFA common names are based on relative coloration. Due to human color perception variation, using color to identify RIFA, BIFA or HIFA is challenging. Fire ant identification traditionally involves molecular or chemical techniques, but a colorimetric test could allow rapid and low-cost identification. In this study, ant integument coloration was measured by spectrophotometer, and color attributes were compared to a combined gas chromatography (GC) index derived from cuticular hydrocarbon and venom alkaloid indices. Significant Pearson Correlation coefficients were found for colony GC index versus color attributes red to green (a*), blue to yellow (b*), chroma (C*), and hue (h*), but not lightness (L*). The RIFA colonies were distinct from BIFA for four of five color attributes and plots of the a*b* and C*h* horizontal axis of the L*a*b* and L*C*h* color spaces. Color attributes for HIFA indices were not distinct from BIFA and RIFA parental species, but HIFA a*b* and C*h* plots were distinct from RIFA and a*b* plots from BIFA. Color attributes a*, b*, and C* increased and h* decreased with GC index in a sinusoidal pattern. In conclusion, most RIFA and BIFA color attributes were distinct and a*b* and C*h* color axes plots had potential to distinguish HIFA from parental species, but coloration of HIFA indices was variable and complicated identifications among HIFA phenotypes, RIFA and BIFA.

Mechanisms of picosecond laser-induced damage in common multilayer dielectric gratings.

The modifications of multilayer dielectric (MLD) gratings arising from laser-induced damage using 0.6-ps and 10-ps laser pulses at 1053 nm are investigated to better understand the damage-initiation mechanisms. Upon damage initiation, sections of the affected grating pillars are removed, thereby erasing the signature of the underlying mechanisms of laser damage. To address this issue, we performed paired studies using macroscopic grating-like features that are 5 mm in width to reveal the laser-damage morphology of the different grating sections: pillar side wall, sole, and pillar top. The results suggest that, similarly to MLD coatings, there are two damage-initiation mechanisms corresponding to the different pulse durations.

Large-aperture coatings for fusion-class laser systems.

Optical coatings for fusion-class laser systems pose unique challenges, given the large substrate sizes, the high intensities incident on the coatings, and the system-focusing requirements, necessitating a well-controlled optical wavefront. Significant advancements have taken place in the past 30 years to achieve the coating capabilities necessary to build laser systems such as the National Ignition Facility, Laser Mégajoule, OMEGA EP, and OMEGA. This work summarizes the coating efforts and advancements to support such system construction and maintenance.

Ellipsometric modeling of serially bi-deposited glancing-angle-deposition coatings.

Ellipsometric modeling of serially bi-deposited glancing-angle-deposition (GLAD) coatings with a high degree of accuracy is imperative for multilayer coatings. High-precision dispersion curves are demonstrated for a wide variety of applications.

Stress compensation by deposition of a nonuniform corrective coating.

Surface deformation by coating stress is compensated by prefiguring the substrate with a radially nonuniform layer of dense silica. Stresses in the compensation layer and reflector are modeled using finite element analysis to determine the optimal thickness profile, with the deposited coating reducing the surface deformation by 90%. This process is intended to allow implementation of both the compensation layer and the traditional multilayer coating in a single vacuum cycle.

Glancing-angle-deposited silica films for ultraviolet wave plates.

Birefringent silica films are formed by glancing-angle deposition to fabricate quarter- and half-wave plates at a wavelength of 351 nm. A multilayer design is implemented to achieve low-loss transmittance with a high 351-nm laser-induced damage threshold.

Influence of absorption-edge properties on subpicosecond intrinsic laser-damage threshold at 1053 nm in hafnia and silica monolayers.

Owing to their relatively high resistance to laser-induced damage, hafnia and silica are commonly used in multilayered optical coatings in high-power laser facilities as high- and low-refractive-index materials, respectively. Here, we quantify the laser-induced-damage threshold (LIDT) at 1053 nm in the short-pulse regime of hafnia and silica monolayers deposited by different fabrication methods, including electron-beam evaporation, plasma ion-assisted deposition and ion-assisted deposition. The results demonstrate that nominally identical coatings fabricated by different deposition techniques and/or vendors can exhibit significantly different damage thresholds. A correlation of the LIDT performance of each material with its corresponding absorption edge is investigated. Our analysis indicates a weak correlation between intrinsic LIDT and the optical gap of each material (Tauc gap) but a much better correlation when considering the spectral characteristics in the Urbach tail spectral range. Spectrophotometry and photothermal absorption were used to provide evidence of the correlation between the strength of the red-shifted absorption tail and reduced LIDT at 1053 nm.

Worker Size, Geographical Distribution, and Introgressive Hybridization of Invasive Solenopsis invicta and Solenopsis richteri (Hymenoptera: Formicidae) in Tennessee.

Worker size and geographical distribution of red imported fire ants (Solenopsis invicta Buren), black imported fire ants (Solenopsis richteri Forel), and their hybrid (S. invicta × S. richteri) (Hymenoptera: Formicidae) were evaluated from colonies sampled across Tennessee. The fire ant species and hybrid status were determined using cuticular hydrocarbon and venom alkaloid indices obtained from gas chromatography and mass spectrometry. Hybrids were the most common fire ant throughout Tennessee. With the exception of a few isolated S. invicta samples, only hybrids were found in east Tennessee, and hybrids predominated in middle Tennessee. In west Tennessee, mixed populations of S. richteri and hybrids were found. Hybrids were more common in west Tennessee than a survey performed a decade earlier. No statistical differences were detected in the average inter-colonial worker size of S. richteri and hybrids. Likewise, average worker size was not related to geographic location in Tennessee. The similarity in average worker size among hybrid colonies with a wide range of cuticular hydrocarbon and venom alkaloid values suggests introgression was not impacting ant size in colonies sampled throughout Tennessee.

Optical properties of oxygen vacancies in HfO2 thin films studied by absorption and luminescence spectroscopy.

Hafnium oxide thin films with varying oxygen content were investigated with the goal of finding the optical signature of oxygen vacancies in the film structure. It was found that a reduction of oxygen content in the film leads to changes in both, structural and optical characteristics. Optical absorption spectroscopy, using nanoKelvin calorimetry, revealed an enhanced absorption in the near-ultraviolet (near-UV) and visible wavelength ranges for films with reduced oxygen content, which was attributed to mid-gap electronic states of oxygen vacancies. Absorption in the near-infrared was found to originate from structural defects other than oxygen vacancy. Luminescence generated by continuous-wave 355-nm laser excitation in e-beam films showed significant changes in the spectral profile with oxygen reduction and new band formation linked to oxygen vacancies. The luminescence from oxygen-vacancy states was found to have microsecond-scale lifetimes when compared with nanosecond-scale lifetimes of luminescence attributed to other structural film defects. Laser-damage testing using ultraviolet nanosecond and infrared femtosecond pulses showed a reduction of the damage threshold with increasing number of oxygen vacancies in hafnium oxide films.

Simulation of internal stress waves generated by laser-induced damage in multilayer dielectric gratings.

Multilayer dielectric (MLD) gratings used in ultrahigh-intensity laser systems often exhibit a laser-induced damage performance below that of their constituent materials. Reduced performance may arise from fabrication- and/or design-related issues. Finite element models were developed to simulate stress waves in MLD grating structures generated by laser-induced damage events. These models specifically investigate the influence of geometric and material parameters on how stress waves can lead to degradation of material structural integrity that can have adverse effects on its optical performance under subsequent laser irradiation: closer impedance matching of the layer materials reduces maximum interface stresses by ~20% to 30%; increasing sole thickness from 50 nm to 500 nm reduces maximum interface stresses by ~50%.

Impact of a counter-rotating planetary rotation system on thin-film thickness and uniformity.

Planetary rotation systems incorporating forward- and counter-rotating planets are used as a means of increasing coating-system capacity for large oblong substrates. Comparisons of planetary motion for the two types of rotating systems are presented based on point tracking for multiple revolutions as well as comparisons of quantitative thickness and uniformity. Counter-rotation system geometry is shown to result in differences in thin-film thickness relative to standard planetary rotation for precision optical coatings. This systematic error in thin-film thickness will reduce deposition yields for sensitive coating designs.

Efficacy of Nootka Oil as a Biopesticide for Management of Imported Fire Ants (Hymenoptera: Formicidae).

Recent concerns regarding the impact of traditional synthetic pesticides on nontarget organisms have generated demand for alternative products with lower environmental impact. This demand has led to increasing focus on plant essential oils as sources of new biopesticides. In this study, we demonstrate that the essential oil of the Alaskan yellow cedar, Cupressus nootkatensis (D. Don) Spach, has activity against hybrid imported fire ant workers, Solenopsis invicta Buren × Solenopsis richteri Forel. In digging assays, ants were repelled by nootka oil and digging continued to be suppressed by nearly 50% in nootka oil-treated sand aged 6 mo in the laboratory. Higher worker mortality was also observed in contact and fumigation assays compared to control checks. In a field drench test, mortality of mounds treated with nootka oil lagged behind mounds treated with bifenthrin treatment for 7 wk, but both nootka oil and bifenthrin had higher mortality than the untreated check at the end of the 12-wk evaluation period. In a band application evaluation, nootka oil plots maintained a 90-95% reduction in fire ant mounds from the 2nd to 17th wk, when new mounds began to intrude on the field plots. The quarantine-approved bifenthrin band treatment maintained 100% control from the 2nd to 24th wk. Although the formulation tested here did not perform to Federal Imported Fire Ant Quarantine standards, other formulations may enable this product to reach 100% control. In addition, nootka oil could be beneficial in situations where ant suppression rather than complete quarantine elimination is the management goal.

Analysis of a planetary-rotation system for evaporated optical coatings.

The impact of planetary design considerations for optical coating deposition is analyzed, including the ideal number of planets, variations in system performance, and the deviation of planet motion from the ideal. System capacity is maximized for four planets, although substrate size can significantly influence this result. Guidance is provided in the design of high-performance deposition systems based on the relative impact of different error modes. Errors in planet mounting such that the planet surface is not perpendicular to the axis of rotation are particularly problematic, suggesting planetary design modifications would be appropriate.

Impact of deposition-rate fluctuations on thin-film thickness and uniformity.

Variations in deposition rate are superimposed on a thin-film deposition model with planetary rotation to determine the impact on film thickness. Variations in magnitude and frequency of the fluctuations relative to the speed of planetary revolution lead to thickness errors and uniformity variations up to 3%. Sufficiently rapid oscillations in the deposition rate have a negligible impact, while slow oscillations are found to be problematic, leading to changes in the nominal film thickness. Superimposing noise as a random fluctuation in the deposition rate has a negligible impact, confirming the importance of any underlying harmonic oscillations in the deposition rate or source operation.

Nano-indentation of single-layer optical oxide thin films grown by electron-beam deposition.

Mechanical characterization of optical oxide thin films is performed using nano-indentation, and the results are explained based on the deposition conditions used. These oxide films are generally deposited to have a porous microstructure that optimizes laser induced damage thresholds, but changes in deposition conditions lead to varying degrees of porosity, density, and possibly the microstructure of the thin film. This can directly explain the differences in the mechanical properties of the film studied here and those reported in literature. Of the four single-layer thin films tested, alumina was observed to demonstrate the highest values of nano-indentation hardness and elastic modulus. This is likely a result of the dense microstructure of the thin film arising from the particular deposition conditions used.

Electron-beam-deposited distributed polarization rotator for high-power laser applications.

Electron-beam deposition of silica and alumina is used to fabricate distributed polarization rotators suitable for smoothing the intensity of large-aperture, high-peak-power lasers. Low-modulation, low-loss transmittance with a high 351-nm laser-damage threshold is achieved.

Plasma-ion-assisted coatings for 15 femtosecond laser systems.

Large-aperture deposition of high-laser-damage-threshold, low-dispersion optical coatings for 15 femtosecond pulses have been developed using plasma-ion-assisted electron-beam evaporation. Coatings are demonstrated over 10 in. aperture substrates.

Management of early-instar Japanese beetle (Coleoptera: Searabaeidae) in field-grown nursery crops.

Numerous field studies were conducted in commercial nurseries in Tennessee from 1996 through 1999 to evaluate chemical and biological treatments, application timing and rates, and method of application for control of early instars of Japanese beetle, Popillia japonica Newman. Insecticide treatments included bifenthrin, bendiocarb, chlorpyrifos, carbaryl, fipronil, halofenozide, imidacloprid, permethrin, tefluthrin, thiamethoxam, and trichlorfon. Biological treatments included entomopathogenic nematodes (Heterorhabditis bacteriophora HP88 or H. marelatus, Bacillus thuringiensis Berliner subspecies japonensis Buibui strain, and Beauveria bassiana (Balsamo) Vuillemin. All treatments were applied on the soil surface or injected into the soil around the base of each tree. Tree type and size varied among and within tests, however, the sampling unit (61-cm-diameter root ball) remained the same throughout all tests. The biological treatments provided poor-to-moderate control (0-75%) of Japanese beetle larvae. Imidacloprid was the most frequently evaluated insecticide and achieved 91-100, 87-100, 83-100, and 41-100% control with applications in May, June, July, and August, respectively. Halofenozide treatments were not significantly different from imidacloprid treatments with one exception. Halofenozide provided 60-87, 85-100, and 82-92 control with applications made in June, July, and August, respectively. Fipronil and thiamethoxam were evaluated to a lesser extent but both performed similarly to imidacloprid. Most other insecticide treatments were less successful in reducing numbers of Japanese beetle larvae and with few exceptions achieved <50% control.

Mycosis of bandedwinged whitefly (Trialeurodes abutilonea) (Homoptera: aleyrodidae) caused by Orthomyces aleyrodis gen. & sp. nov. (Entomophthorales: Entomophthoraceae).

A new genus and species of fungus, Orthomyces aleyrodis Steinkraus, Humber & Oliver gen. & sp. nov. (Entomophthorales: Entomophthoraceae) is described. In 1994 and 1995, this fungus caused epizootics in high populations of bandedwinged whitefly (Trialeurodes abutilonea) on cotton and cocklebur in Alabama. In 1996, T. abutilonea populations were lower and no infected specimens were found. This is the first report of an entomophthoralean infecting an aleyrodid in the New World and the first report of entomophthoralean epizootics in whiteflies.

Quantification of the major brown shrimp allergen Pen a 1 (tropomyosin) by a monoclonal antibody-based sandwich ELISA.

BACKGROUND: Among 13 allergens found in extracts of cooked brown shrimp (Penaeus aztecus) the 36 kd muscle protein tropomyosin has been identified as the only major shrimp allergen (Pen a 1). Cross-reacting molecules with similar molecular weights were detected in other crustacea species such as crab, lobster, and crawfish. Because Pen a 1 and Pen a 1-like allergens are important in crustacea allergy, the aim of this study was to develop a monoclonal antibody (mAb)-based sandwich ELISA to quantify Pen a 1 and to evaluate Pen a 1 levels in four commercial shrimp, crab, and lobster extracts. METHODS: Two Pen a 1-specific mAbs with different epitope specificities were selected. ELISA plates coated with captured mAb 3.2 were incubated with samples containing Pen a 1. Bound Pen a 1 was detected by a combination of biotinylated mAb 4.9.5 and alkaline phosphatase-labeled streptavidin. RESULTS: The optimized sandwich ELISA could detect Pen a 1 concentrations ranging from 4 to 125 ng/ml. Four commercial shrimp extracts demonstrated a 40-fold difference in Pen a 1 levels (24 to 920 microg/ml). Crab and lobster extracts contained detectable levels of Pen a 1-like proteins. No reactivity to cockroach, house dust mite, oyster, codfish, or peanut extracts was detected, which indicates that the developed assay is crustacea-specific. CONCLUSION: A sensitive sandwich assay was developed to quantify Pen a 1. This assay will be helpful to standardize shrimp extracts in regard to the content of the major allergen, Pen a 1, and to study cross-reactivities among and evaluate occupational exposure to different crustacea species.