1,308 research outputs found

    An experimental study of the turbulent boundary layer on a transport wing in subsonic and transonic flow

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    The upper surface boundary layer on a transport wing model was extensively surveyed with miniature yaw probes at a subsonic and a transonic cruise condition. Additional data were obtained at a second transonic test condition, for which a separated region was present at mid-semispan, aft of mid-chord. Significant variation in flow direction with distance from the surface was observed near the trailing edge except at the wing root and tip. The data collected at the transonic cruise condition show boundary layer growth associated with shock wave/boundary layer interaction, followed by recovery of the boundary layer downstream of the shock. Measurements of fluctuating surface pressure and wingtip acceleration were also obtained. The influence of flow field unsteadiness on the boundary layer data is discussed. Comparisons among the data and predictions from a variety of computational methods are presented. The computed predictions are in reasonable agreement with the experimental data in the outboard regions where 3-D effects are moderate and adverse pressure gradients are mild. In the more highly loaded mid-span region near the trailing edge, displacement thickness growth was significantly underpredicted, except when unrealistically severe adverse pressure gradients associated with inviscid calculations were used to perform boundary layer calculations

    The effect of ratio and interval training on Pavlovian-instrumental transfer in mice.

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    Conditional stimuli (CS) that are paired with reward can be used to motivate instrumental responses. This process is called Pavlovian-instrumental transfer (PIT). A recent study in rats suggested that habitual responses are particularly sensitive to the motivational effects of reward cues. The current experiments examined this idea using ratio and interval training in mice. Two groups of animals were trained to lever press for food pellets that were delivered on random ratio or random interval schedules. Devaluation tests revealed that interval training led to habitual responding while ratio training produced goal-directed actions. The presentation of CSs paired with reward led to positive transfer in both groups, however, the size of this effect was much larger in mice that were trained on interval schedules. This result suggests that habitual responses are more sensitive to the motivational influence of reward cues than goal-directed actions. The implications for neurobiological models of motivation and drug seeking behaviors are discussed

    Star-Forming Galaxies at z~2: An Emerging Picture of Galaxy Dynamics and Assembly

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    In these proceedings, we summarize recent results from our "SINS" VLT/SINFONI integral-field survey, focusing on the 52 detected UV/optically-selected star-forming galaxies at z~2. Our H-alpha emission-line imaging and kinematic data of these systems illustrates that a substantial fraction (> 1/3) of these galaxies are large, rotating disks and that these disks are clumpy, thick, and forming stars rapidly. We compare these systems to local disk scaling relations and find that the backbones of these relations are already in place at z~2. Detailed analysis of the large disks in our sample provides strong evidence that this population cannot result from a merger-dominated formation history and instead must be assembled by the smooth but rapid inflow of gas along filaments. These systems will then secularly evolve from clump-dominated disks to bulge-dominated disks on short timescales, a phenomenon that is observed in our SINS observations and is consistent with predictions from numerical simulations. These results provide new and exciting insights into the formation of bulge-dominated galaxies in the local Universe.Comment: 7 pages, to appear in the proceedings of "Galaxy Evolution: Emerging Insights and Future Challenges," Austin, TX, 11-14 Nov 200

    Relating functional and structural signatures of Parkinson’s disease to changes in dopamine signalling: A PET/fMRI study

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    Cognitive impairments in early Parkinson\u27s disease are known to be linked to complex changes in the dopamine system within the brain. For example, dopamine-producing neurons in one key region of the brain are significantly degenerated, but those in another are spared. Dopamine-replacement therapy (DRT) has been pursued and it has produced significant improvements in certain cognitive functions - unfortunately it also produced significant impairments in others.https://ir.lib.uwo.ca/brainscanprojectsummaries/1019/thumbnail.jp

    Psychometric Testing of the Self-Care of Heart Failure Index

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    BACKGROUND: Self-care is believed to improve outcomes in heart failure (HF) patients. However, research testing this assumption is hampered by difficulties in measuring self-care. The purpose of this study was to evaluate the psychometric properties of a revised instrument measuring self-care in persons with HF, the Self-Care of Heart Failure Index (SCHFI). The SCHFI is a self-report measure comprised of 15 items rated on a 4-point response scale and divided into 3 subscales. METHODS AND RESULTS: Psychometric testing was done using data from 760 HF patients (age 70.36 +/- 12.3 years, 51% male) from 7 sites in the United States. Reliability of the SCHFI (alpha.76) was adequate. Reliability of the Self-Care Maintenance subscale was lower than desired (alpha.56) but the reliability of the other subscales was adequate: Self-Care Management (alpha.70) and Self-Care Self-Confidence (alpha.82). Construct validity was supported with satisfactory model fit on confirmatory factor analysis (NFI=.69, CFI.73). Construct validity was supported further with significant total and subscale (all P \u3c .05) differences between patients experienced with HF and those newly diagnosed, consistent with the underlying theory. CONCLUSION: Low reliability of the Self-Care Maintenance subscale was expected because the items reflect behaviors known to vary in individuals. The reliability and validity of the SCHFI are sufficient to support its use in clinical research

    A Report on: Engaging Private sector actors in cocoa value chains in adopting Climate Smart Cocoa (CSC) Practices in Ghana

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    International Institute of Tropical Agriculture (IITA) and its consortium members (Sustainable Food Lab-SFL, Root Capital-RC, Rainforest Alliance-RA and CIAT) on the Climate Change, Agriculture and Food Security (CCAFS) Flagship Project entitled, “Mainstreaming Climate Smart Value Chains “has for the past two years laid the foundation to engage the private sector in piloting new CSC recommendations. A period of diagnostics has culminated into decision support tools ready for use in the pilots in three climate impact zones delineated by the project (see map). The objective of meetings with the private sector was to scope their commitment for Climate Smart Agriculture (CSA) adoption. It was also to understand whether the private sector have on-going initiatives towards addressing the challenges of CC in the cocoa value chain. To do this, some of the private sector companies were contacted for possible collaboration with the consortium to pilot and co-learn with the implementation of the new Climate Smart Cocoa (CSC) practices with their farmers. The team that represented the consortium in the process of engaging the private sector was mainly from IITA and SFL

    Analysis of a cricket's chirp

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    14 p. : ill. ; 23 cm
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