Detection of Prolonged Diapause of Northern Corn Rootworm in Michigan (Coleoptera: Chrysomelidae)

Prolonged diapause of northern corn rootworm, while known from other Midwestern states, has not previously been reported in Michigan. Populations of northern corn rootworm, (Diabrotica barberi) from two first-year corn fields in Genesee County, Michigan were examined for prolonged egg diapause. Pro- longed diapause was suspected in these populations due to an unusually high proportion of northern versus western corn rootworms in these fields. Eggs obtained from females collected at these sites were reared in the laboratory for two years. The presence of the prolonged diapause trait was confirmed in one population by eggs which hatched following two simulated winters (7.3%). None of the eggs m the second population hatched following the second chill period, however, some eggs in this population remained in apparent diapause at the end of two years. The potential for using observed population shifts in favor of D. barberi as an early warning of the expansion of prolonged diapause in a population is discussed

Modification of silicon carbide fibers for use in SiC/Ti composites

The degradation of silicon carbide fibers during exposure to conditions typical of composite fabrication was investigated. The tensile strength of pristine fibers and fibers sputtered with thin metal coatings were determined before and after treatment at 870 C for one hour in vacuum. Each fiber strength distribution was related by an analytical procedure to a projected composite ultimate tensile strength (PC UTS). The results indicate that a thin aluminum diffusion barrier can yield a 150 percent increase in PC UTS over the baseline SiC/Ti system

Space station common module network topology and hardware development

Conceptual space station common module power management and distribution (SSM/PMAD) network layouts and detailed network evaluations were developed. Individual pieces of hardware to be developed for the SSM/PMAD test bed were identified. A technology assessment was developed to identify pieces of equipment requiring development effort. Equipment lists were developed from the previously selected network schematics. Additionally, functional requirements for the network equipment as well as other requirements which affected the suitability of specific items for use on the Space Station Program were identified. Assembly requirements were derived based on the SSM/PMAD developed requirements and on the selected SSM/PMAD network concepts. Basic requirements and simplified design block diagrams are included. DC remote power controllers were successfully integrated into the DC Marshall Space Flight Center breadboard. Two DC remote power controller (RPC) boards experienced mechanical failure of UES 706 stud-mounted diodes during mechanical installation of the boards into the system. These broken diodes caused input to output shorting of the RPC's. The UES 706 diodes were replaced on these RPC's which eliminated the problem. The DC RPC's as existing in the present breadboard configuration do not provide ground fault protection because the RPC was designed to only switch the hot side current. If ground fault protection were to be implemented, it would be necessary to design the system so the RPC switched both the hot and the return sides of power

Revisiting Extraversion and Leadership Emergence: A Social Network Churn Perspective

One of the classic relationships in personality psychology is that extraversion is associated with emerging as an informal leader. However, recent findings raise questions about the longevity of extraverted individuals as emergent leaders. Here, we adopt a social network churn perspective to study the number of people entering, remaining in, and leaving the leadership networks of individuals over time. We propose that extraverted individuals endure as emergent leaders in networks over time, but experience significant changes in the people being led, including the loss of people who once considered them a leader but now no longer do. In Study 1 (N = 545), extraverted individuals had a larger number of new and remaining people in their leadership networks, but also lost more people, above and beyond differences in initial leadership network size. In Study 2 (N = 764), we replicated and extended these results in an organizational sample while controlling for alternative explanations such as formal rank, network size, self-monitoring, and narcissism. Extraversion predicted the number of people entering, remaining in, and leaving leadership networks over time. Our findings suggest that while extraverted individuals tend to emerge as leaders, they are also more likely to experience greater network churn—they tend to lead different people over time and leave people in their wake who once perceived them a leader but now no longer do. We discuss the challenges posed by this network churn perspective for extraverted emergent leaders and highlight its importance for our understanding of extraversion and emergent leadership

Peeled film GaAs solar cells for space power

Gallium arsenide (GaAs) peeled film solar cells were fabricated, by Organo-Metallic Vapor Phase Epitaxy (OMVPE), incorporating an aluminum arsenide (AlAs) parting layer between the device structure and the GaAs substrate. This layer was selectively removed by etching in dilute hydrofloric (HF) acid to release the epitaxial film. Test devices exhibit high series resistance due to insufficient back contact area. A new design is presented which uses a coverglass superstrate for structural support and incorporates a coplanar back contact design. Devices based on this design should have a specific power approaching 700 W/Kg

Contact-Induced Emigration of Potato Leafhopper (Homoptera: Cicadellidae) from Alfalfa-Forage Grass Mixtures

Studies were conducted to evaluate the mechanisms leading to increased potato leafhopper, Empoasca fabae (Harris), emigration from alfalfa-forage grass mixtures. A laboratory behavioral bioassay was used to measure daily emigration rates of adult leafhoppers from alfalfa, Medicago sativa L.; smooth bromegrass, Bromus inermis Leyss.; orchardgrass, Dactylis glomerata L.; and timothy, Phleum pratense L., alone and in 1:1 mixtures of each grass with alfalfa. Emigration was ≍9-fold greater from pure bromegrass and orchardgrass treatments versus alfalfa alone, and ≍5-fold greater than from mixtures of alfalfa and each grass species. In a 2nd experiment, alfalfa and forage grasses were separated by a barrier permeable to plant volatiles. Only 31% of the potato leafhoppers placed on alfalfa adjacent to either alfalfa or grass emigrated. However, when introduced to the side containing a forage grass, <85% of the leafhoppers emigrated, regardless of adjacent plant. Thus, stimuli obtained from physical contact with the grass versus grass volatiles alone were required to elicit emigration. Observations of potato leafhoppers on single plants of smooth bromegrass, orchardgrass, and alfalfa revealed that individuals fed on all 3 species; however, the frequency and duration of probing differed as did mean residency time (10.7 h alfalfa, 7.5 h bromegrass, 5.9 h orchardgrass). These experiments suggested that physical contact is necessary to elicit emigration from grasses. By increasing emigration, alfalfa-forage grass mixtures may reduce potato leafhopper damage to alfalfa. Additionally, intercropping with forage grasses may lower the number of feeding bouts on alfalfa and reduce subsequent hopperbur

Detection of Prolonged Diapause of Northern Corn Rootworm in Michigan (Coleoptera: Chrysomelidae)

Prolonged diapause of northern corn rootworm, while known from other Midwestern states, has not previously been reported in Michigan. Populations of northern corn rootworm, (Diabrotica barberi) from two first-year corn fields in Genesee County, Michigan were examined for prolonged egg diapause. Pro- longed diapause was suspected in these populations due to an unusually high proportion of northern versus western corn rootworms in these fields. Eggs obtained from females collected at these sites were reared in the laboratory for two years. The presence of the prolonged diapause trait was confirmed in one population by eggs which hatched following two simulated winters (7.3%). None of the eggs m the second population hatched following the second chill period, however, some eggs in this population remained in apparent diapause at the end of two years. The potential for using observed population shifts in favor of D. barberi as an early warning of the expansion of prolonged diapause in a population is discussed

Demonstration of an Integrated Pest Management Program for Wheat in Tajikistan

Citation: Landis, D. A., Saidov, N., Jaliov, A., El Bouhssini, M., Kennelly, M., Bahlai, C., . . . Maredia, K. (2016). Demonstration of an Integrated Pest Management Program for Wheat in Tajikistan. Journal of Integrated Pest Management, 7(1), 9. doi:10.1093/jipm/pmw010Citation: Landis, D., Saidav, N., . . . & Maredia, K. (2016). Demonstration of an Integrated Pest Management Program for Wheat in Tajikistan. Journal of Integrated Pest Management, 7(1), 1-9. https://doi.org/10.1093/jipm/pmw010Wheat is an important food security crop in central Asia but frequently suffers severe damage and yield losses from insect pests, pathogens, and weeds. With funding from the United States Agency for International Development, a team of scientists from three U.S. land-grant universities in collaboration with the International Center for Agricultural Research in Dry Areas and local institutions implemented an integrated pest management (IPM) demonstration program in three regions of Tajikistan from 2011 to 2014. An IPM package was developed and demonstrated in farmer fields using a combination of crop and pest management techniques including cultural practices, host plant resistance, biological control, and chemical approaches. The results from four years of demonstration/research indicated that the IPM package plots almost universally had lower pest abundance and damage and higher yields and were more profitable than the farmer practice plots. Wheat stripe rust infestation ranged from 30% to over 80% in farmer practice plots, while generally remaining below 10% in the IPM package plots. Overall yield varied among sites and years but was always at least 30% to as much as 69% greater in IPM package plots. More than 1,500 local farmers-40% women-were trained through farmer field schools and field days held at the IPM demonstration sites. In addition, students from local agricultural universities participated in on-site data collection. The IPM information generated by the project was widely disseminated to stakeholders through peer-reviewed scientific publications, bulletins and pamphlets in local languages, and via Tajik national television