1,516 research outputs found
Dual output variable pitch turbofan actuation system
An improved actuating mechanism was provided for a gas turbine engine incorporating fan blades of the variable pitch variety, the actuator adapted to rotate the individual fan blades within apertures in an associated fan disc. The actuator included means such as a pair of synchronizing ring gears, one on each side of the blade shanks, and adapted to engage pinions disposed thereon. Means were provided to impart rotation to the ring gears in opposite directions to effect rotation of the blade shanks in response to a predetermined input signal. In the event of system failure, a run-away actuator was prevented by an improved braking device which arrests the mechanism
A study of commuter airplane design optimization
Problems of commuter airplane configuration design were studied to affect a minimization of direct operating costs. Factors considered were the minimization of fuselage drag, methods of wing design, and the estimated drag of an airplane submerged in a propellor slipstream; all design criteria were studied under a set of fixed performance, mission, and stability constraints. Configuration design data were assembled for application by a computerized design methodology program similar to the NASA-Ames General Aviation Synthesis Program
From Campus to Corporation: Using Developmental Assessment Centers to Facilitate Students’ Next Career Steps
introduction
For the things we have to learn before we can do them, we learn by doing them. —Aristotle, The Nicomachean Ethics
Honors graduates have much to learn when transitioning into their first position after college. For instance, workplaces have an entirely different culture and set of expectations from undergraduate honors classrooms (Wendlandt & Rochlen). Furthermore, the skills they need to become successful employees or graduate students are different from those required of successful honors college students, with a greater emphasis on communication skills (Stevens) as one example.
Honors students are bright, curious, and hard-working (Achterberg), and honors programs give them the opportunity to foster accelerated academic success and access to extensive resources. Although honors programs are extremely beneficial to students intellectually and academically, many honors students graduate without adequate knowledge of the skills and capabilities that they are expected to have in the workplace. Thus, these recent graduates are often intellectually but not organizationally prepared.
At the Pennsylvania State University’s Schreyer Honors College, we have found a way to mitigate this gap in skills and understanding by operating an assessment center, a work simulation program designed to allow students to experience organizational life while also receiving crucial feedback from those with experience in the workforce. The value of assessment centers lies in enhancing scholars’ educational and career development, and successful implementation requires important considerations, processes, and resources. The detailed story of Schreyer Honors College’s Leadership Assessment Center elaborates on the factors that have been crucial to the team’s success in providing this opportunity to Penn State’s honors students over the past ten years and might inspire other academic institutions to consider creating assessment centers for their scholars’ education.
Although the Assessment Center’s enhanced educational experience for honors college students is its primary goal, the benefits extend to all involved in the center, including graduate students, alumni, and the undergraduate students and faculty who serve as administrators for the center. A successful assessment center can also benefit the college itself as a tool for recruiting future students. As a former dean of Schreyer pointed out early on, “This gives me an edge when talking to prospective parents and students who are considering Penn State versus other institutions. The progressive nature of our overall program is enhanced by offering unique opportunities like the assessment center.
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Monitoring and Evaluation of Smolt Migration in the Columbia Basin : Volume XV : Evaluation of the 2007 Predictions of the Run-Timing of Wild and Hatchery-Reared Salmon and Steelhead Smolts to Rock Island, Lower Granite, McNary, John Day, and Bonneville Dams using Program RealTime.
Program RealTime provided monitoring and forecasting of the 2007 inseason outmigrations via the internet for 26 PIT-tagged stocks of wild ESU Chinook salmon and steelhead to Lower Granite and/or McNary dams, one PIT-tagged hatchery-reared ESU of sockeye salmon to Lower Granite Dam, one PIT-tagged wild stock of sockeye salmon to McNary Dam, and 20 passage-indexed runs-at-large, five each to Rock Island, McNary, John Day, and Bonneville dams. Nineteen stocks are of wild yearling Chinook salmon which were captured, PIT-tagged, and released at sites above Lower Granite Dam in 2007 and have at least one year's historical migration data previous to the 2007 migration. These stocks originate in 19 tributaries of the Salmon, Grande Ronde and Clearwater Rivers, all tributaries to the Snake River, and are subsequently detected through tag identification and monitored at Lower Granite Dam. Seven wild PIT-tagged runs-at-large of Snake or Upper Columbia River ESU salmon and steelhead were monitored at McNary Dam. Three wild PIT-tagged runs-at-large were monitored at Lower Granite Dam, consisting of the yearling and subyearling Chinook salmon and the steelhead runs. The hatchery-reared PIT-tagged sockeye salmon stock from Redfish Lake was monitored outmigrating through Lower Granite Dam. Passage-indexed stocks (stocks monitored by FPC passage indices) included combined wild and hatchery runs-at-large of subyearling and yearling Chinook, coho, and sockeye salmon, and steelhead forecasted to Rock Island, McNary, John Day, and Bonneville dams
Predicting Changes in Bee Assemblages Following State Transitions at North American Dryland Ecotones
Drylands worldwide are experiencing ecosystem state transitions: the expansion of some ecosystem types at the expense of others. Bees in drylands are particularly abundant and diverse, with potential for large compositional differences and seasonal turnover across ecotones. To better understand how future ecosystem state transitions may influence bees, we compared bee assemblages and their seasonality among sites at the Sevilleta National Wildlife Refuge (NM, USA) that represent three dryland ecosystem types (and two ecotones) of the southwestern U.S. (Plains grassland, Chihuahuan Desert grassland, and Chihuahuan Desert shrubland). Using passive traps, we caught bees during two-week intervals from March–October, 2002–2014. The resulting dataset included 302 bee species and 56 genera. Bee abundance, composition, and diversity differed among ecosystems, indicating that future state transitions could alter bee assemblage composition in our system. We found strong seasonal bee species turnover, suggesting that bee phenological shifts may accompany state transitions. Common species drove the observed trends, and both specialist and generalist bee species were indicators of ecosystem types or months; these species could be sentinels of community-wide responses to future shifts. Our work suggests that predicting the consequences of global change for bee assemblages requires accounting for both within-year and among-ecosystem variation
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Nevada Test Site Perspective on Characterization and Loading of Legacy Transuranic Drums Utilizing the Central Characterization Project
The Nevada Test Site (NTS) has successfully completed a multi-year effort to characterize and ship 1860 legacy transuranic (TRU) waste drums for disposal at the Waste Isolation Pilot Plant (WIPP), a permanent TRU disposal site. This has been a cooperative effort among the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO), the U.S. Department of Energy, Carlsbad Field Office (DOE/CBFO), the NTS Management and Operations (M&O) contractor Bechtel Nevada (BN), and various contractors under the Central Characterization Project (CCP) umbrella. The success is due primarily to the diligence, perseverance, and hard work of each of the contractors, the DOE/CBFO, and NNSA/NSO, along with the support of the U.S. Department of Energy, Headquarters (DOE/HQ). This paper presents, from an NTS perspective, the challenges and successes of utilizing the CCP for obtaining a certified characterization program, sharing responsibilities for characterization, data validation, and loading of TRU waste with BN to achieve disposal at WIPP from a Small Quantity Site (SQS) such as the NTS. The challenges in this effort arose from two general sources. First, the arrangement of DOE/CBFO contractors under the CCP performing work and certifying waste at the NTS within a Hazard Category 2 (HazCat 2) non-reactor nuclear facility operated by BN, presented difficult challenges. The nuclear safety authorization basis, safety liability and responsibility, conduct of operations, allocation and scheduling of resources, and other issues were particularly demanding. The program-level and field coordination needed for the closely interrelated characterization tasks was extensive and required considerable effort by all parties. The second source of challenge was the legacy waste itself. None of the waste was generated at the NTS. The waste was generated at Lawrence Livermore National Laboratory (LLNL), Lawrence Berkeley Laboratory (LBL), Lynchburg, Rocky Flats Environmental Technology Site (RFETS), and a variety of other sites over 20 years ago, making the development of Acceptable Knowledge a significant and problematic effort. In addition, the characterization requirements, and data quality objectives for shipment and WIPP disposal today, were non-existent when this waste was generated, resulting in real-time adjustments to unexpected conditions
Anti-TNF-α antibody allows healing of joint damage in polyarthritic transgenic mice
Anti-tumor-necrosis-factor-α (TNF-α) monoclonal antibody was used to treat Tg197 transgenic mice, which constitutively produce human TNF-α (hTNF-α) and develop a progressive polyarthritic disease. Treatment of both young (7- or 8-week-old) and aged (27- or 28-week-old) mice commenced when at least two limbs showed signs of moderate to severe arthritis. The therapeutic efficacy of anti-TNF-α antibody was assessed using various pathological indicators of disease progression. The clinical severity of arthritis in Tg197 mice was significantly reduced after anti-TNF-α treatment in comparison with saline-treated mice and in comparison with baseline assessments in both young and aged mice. The treatment with anti-TNF-α prevented loss of body weight. Inflammatory pathways as reflected by elevated circulating hTNF-α and local expression of various proinflammatory mediators were all diminished by anti-TNF-α treatment, confirming a critical role of hTNF-α in this model of progressive polyarthritis. More importantly, the amelioration of the disease was associated with reversal of existing structural damage, including synovitis and periosteal bone erosions evident on histology. Repair of cartilage was age dependent: reversal of cartilage degradation after anti-TNF-α treatment was observed in young mice but not in aged mice
A noise-reduction GWAS analysis implicates altered regulation of neurite outgrowth and guidance in autism
<p>Abstract</p> <p>Background</p> <p>Genome-wide Association Studies (GWAS) have proved invaluable for the identification of disease susceptibility genes. However, the prioritization of candidate genes and regions for follow-up studies often proves difficult due to false-positive associations caused by statistical noise and multiple-testing. In order to address this issue, we propose the novel GWAS noise reduction (GWAS-NR) method as a way to increase the power to detect true associations in GWAS, particularly in complex diseases such as autism.</p> <p>Methods</p> <p>GWAS-NR utilizes a linear filter to identify genomic regions demonstrating correlation among association signals in multiple datasets. We used computer simulations to assess the ability of GWAS-NR to detect association against the commonly used joint analysis and Fisher's methods. Furthermore, we applied GWAS-NR to a family-based autism GWAS of 597 families and a second existing autism GWAS of 696 families from the Autism Genetic Resource Exchange (AGRE) to arrive at a compendium of autism candidate genes. These genes were manually annotated and classified by a literature review and functional grouping in order to reveal biological pathways which might contribute to autism aetiology.</p> <p>Results</p> <p>Computer simulations indicate that GWAS-NR achieves a significantly higher classification rate for true positive association signals than either the joint analysis or Fisher's methods and that it can also achieve this when there is imperfect marker overlap across datasets or when the closest disease-related polymorphism is not directly typed. In two autism datasets, GWAS-NR analysis resulted in 1535 significant linkage disequilibrium (LD) blocks overlapping 431 unique reference sequencing (RefSeq) genes. Moreover, we identified the nearest RefSeq gene to the non-gene overlapping LD blocks, producing a final candidate set of 860 genes. Functional categorization of these implicated genes indicates that a significant proportion of them cooperate in a coherent pathway that regulates the directional protrusion of axons and dendrites to their appropriate synaptic targets.</p> <p>Conclusions</p> <p>As statistical noise is likely to particularly affect studies of complex disorders, where genetic heterogeneity or interaction between genes may confound the ability to detect association, GWAS-NR offers a powerful method for prioritizing regions for follow-up studies. Applying this method to autism datasets, GWAS-NR analysis indicates that a large subset of genes involved in the outgrowth and guidance of axons and dendrites is implicated in the aetiology of autism.</p
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