Interactions Between Host-plant Volatiles and the Sex Pheromones of the Bird Cherry-oat Aphid, <Emphasis Type="Italic">Rhopalosiphum padi</Emphasis> and the Damson-hop Aphid, <Emphasis Type="Italic">Phorodon humuli</Emphasis>

The bird cherry-oat aphid, Rhopalosiphum padi (L.), and the damson-hop aphid, Phorodon humuli (Schrank), migrate at the same time of year and colonize closely related Prunus spp. as primary hosts, but utilize (1R,4aS,7S,7aR)-nepetalactol and (1RS,4aR,7S,7aS)-nepetalactol, respectively, as sex pheromones. Interactions between these sex pheromones and benzaldehyde and methyl salicylate, plant volatiles common to primary hosts of both species, were investigated to assess whether they confer reproductive isolation between these species. Female autumn migrants (gynoparae) and males of these two species were caught in the field with water traps baited with their respective sex pheromones. Rhopalosiphum padi gynoparae and males also responded positively to benzaldehyde. Release of either benzaldehyde or methyl salicylate with the conspecific sex pheromone increased catches of both species of aphid. However, releasing both plant volatiles with the sex pheromone of R. padi increased catches of gynoparae and males, but reduced those with the sex pheromone of P. humuli. These results support the hypothesis that specific plant volatiles synergize responses of autumn migrating aphids to their sex pheromone. Because these interactions are species-specific, they may be important in allowing males to discriminate between conspecific sexual females (oviparae) and those of other aphid species.     

Evaluation of low ash impact sorbent injection technologies for mercury control at a Texas lignite/PRB fired power plant

A sorbent injection test program was carried out at NRG Texas Power LLC's (NRG) Limestone Electric Generating Station (LMS). LMS fires a 30/70 blend of Powder River Basin (PRB) and Texas Lignite, and is equipped with a cold-side electrostatic precipitator (ESP) and wet scrubber. The plant markets its fly ash for beneficial use, so development of a low ash impact mercury control technology is important to the economics of implementing a mercury control system. In addition to standard activated carbon injection, two different low ash impact mercury control technologies were evaluated in parametric tests: low ash impact sorbents and Toxecon™ II. The parametric ACI test program conducted at LMS demonstrated that high (>90%) levels of mercury removal could be achieved with carbon sorbents. The Toxecon™ II design used at LMS did not provide for as high a mercury removal as injection upstream of the ESP, likely due to poor coverage of the cross-sectional area of the ESP. Limited concrete testing was performed with simulated ash/carbon mixtures. As expected, the amount of air-entraining additive required increased with increasing carbon content in the ash. However, it appeared that small amounts of non-passivated carbon may be acceptable in fly ash for concrete use.     

A multicomponent intervention to prevent partner violence within an existing service intervention.

Intimate partner violence (IPV) is an enormous public health problem that results in injury, health problems, and substantial cost to society. Despite having a grasp of the scope of IPV, public health officials and workers know little about how to prevent it. The few empirically established primary prevention programs consist of school-based curricula targeting high school students. Additional venues for IPV prevention are needed, especially for women at elevated risk. This article describes a preventive intervention for IPV consisting of three components: (a) a structured assessment for IPV; (b) a brochure-driven intervention for women experiencing IPV, including safety planning, referrals, and advocacy; and (c) a skills-based curriculum delivered to all participants that focuses on improving relationship decisions and outcomes. While this intervention could potentially be delivered in a multitude of clinical settings, this article focuses on its delivery within a home visitation program for young, disadvantaged new mothers, a population known to be at increased risk for IPV. If found to be effective, this intervention could be incorporated into many service delivery systems, with broad-based clinical implications for IPV prevention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel-Fed Traveling Wave Photodetector for > 100-GHz Applications

A fully packaged traveling wave photodetector (TWPD) with monolithically integrated optical power splitter for high-speed high-power applications in excess of 100 GHz is demonstrated. The detector module provides a responsivity of 0.24 A/W with a polarization dependence of only 0.2 dB at 1.55 mum wavelength and is suitable for the detection of RZ data rates in excess of 80 Gbit/s with unsaturated peak voltages of >0.5 V. Chip-based measurements show a broadband impedance match, a 3 dB bandwidth of 80 GHz and a maximum electrical output power of -2.5 dBm at 150 GHz.     

Effect of Current Crowding on Frequency Response of a Stepped Planar RF Transmission-Line Lowpass Filter for Power Electronics

This paper relates to prototype design studies of a stepped-tapered (in width) planar Cu-Al₂O₃-Ni-BaTiO₃-Ni-Al₂O ₃-Cu radio frequency (RF) lowpass filter for an integrated power electronics module. An empirical cascaded one-dimensional (1-D) current-crowding model, using ABCD matrices, is employed to explain the anomalous, and degraded, high-frequency roll-off slope of the Ni-BaTiO ₃-Ni attenuator segment in the desired (wide-to-narrow) forward connection. Good agreement between theory and experiment is obtained with the empirical current-crowding model, which incorporates changes in the resistance and self-inductance of the Ni conductor as functions of current crowding and skin depth. Additional support for postulated current crowding was inferred from two-dimensional (2-D) finite-element analysis (FEA) modeling of the electromagnetic field distributions in the individual attenuator segments. Such studies could serve as an aid to the design of other planar structures of improved tapered or exponential shape for enhancing the high-frequency roll-off response and slope     

Stability of a class of linear switching systems with time delay

We consider a switching system composed of a finite number of linear delay differential equations (DDEs). It has been shown that the stability of a switching system composed of a finite number of linear ordinary differential equations (ODEs) may be achieved by using a common Lyapunov function method switching rule. We modify this switching rule for ODE systems to a common Lyapunov functional method switching rule for DDE systems and show that it stabilizes our model. Our result uses a Riccati-type Lyapunov functional under a condition on the time delay.     

Instrumentation for high-speed digital recording of switchingsurges

Three sophisticated monitoring systems were developed and used to make unattended measurements of over 600 switching surges on 33 motors at 11 different utilities. The authors describe in detail one of the recording systems which relies on ECL (emitted coupler logic) digital electronics and high-speed commercial digitizers to measure the multiple, fast-risetime, high-voltage surges typically created by vacuum circuit breaker switching operations. This three-channel monitoring system is capable of digitizing a voltage waveform at 5 ns intervals and has 64 K bytes of memory per channel. The digitizer sampling rate is varied in real time to allow high-speed recording of up to 256 transients. Wideband capacitive voltage dividers with a flat response from below power frequencies to 20 MHz were designed to bolt directly onto the motor terminals and were used to couple the surges to the monitoring system. Results from typical field measurements made with this system on motors controlled by vacuum switchgear are also reported     

Induction of acute phase gene expression by brain irradiation

PURPOSE: To investigate the in vivo acute phase molecular response of the brain to ionizing radiation. METHODS AND MATERIALS: C3Hf/Sed/Kam mice were given midbrain or whole-body irradiation. Cerebral expression of interleukins (IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6), interferon (IFN-gamma), tumor necrosis factors (TNF-alpha and TNF-beta), intercellular adhesion molecule-1 (ICAM-1), inducible nitric oxide synthetase (iNOS), von Willebrand factor (vWF), alpha 1-antichymotrypsin (EB22/5.3), and glial fibrillary acidic protein (GFAP) was measured at various times after various radiation doses by ribonuclease (RNase) protection assay. The effects of dexamethasone or pentoxifylline treatment of mice on radiation-induced gene expression were also examined. RESULTS: Levels of TNF-alpha, IL-1 beta, ICAM-1, EB22/5.3 and to a lesser extent IL-1 alpha and GFAP, messenger RNA were increased in the brain after irradiation, whether the dose was delivered to the whole body or only to the midbrain. Responses were radiation dose dependent, but were not found below 7 Gy; the exception being ICAM-1, which was increased by doses as low as 2 Gy. Most responses were rapid, peaking within 4-8 h, but antichymotrypsin and GFAP responses were delayed and still elevated at 24 h, by which time the others had subsided. Pretreatment of mice with dexamethasone or pentoxifylline suppressed radiation-induced gene expression, either partially or completely. Dexamethasone was more inhibitory than pentoxifylline at the doses chosen. CONCLUSIONS: The initial response of the brain to irradiation involves expression of inflammatory gene products, which are probably responsible for clinically observed early symptoms of brain radiotherapy. This mechanism explains the beneficial effects of the clinical use of steroids in such circumstances.