527 research outputs found
Paper Session III-C - Advanced Mechanisms For Space Applications
The Air Force Research Laboratory (AFRL) is currently engaged in developing and demonstrating several advanced spacecraft and launch vehicle mechanism technologies. A variety of mechanisms are required to accomplish spacecraft and launch vehicle functions such as deployment, articulation, positioning, and isolation. Current off-the-shelf mechanisms such as pyrotechnics, gimbals, paraffin actuators, and electro-mechanical devices may not be able to meet future satellite requirements. For this reason, advanced technologies are needed that will increase mechanism efficiency in terms of cost, weight, reliability/survivability, and power consumption. In addition to developing these technologies, it is necessary to prove them in flight demonstrations in order to make technology transition feasible. This paper summarizes the status of several space-related programs being conducted by AFRL for developing and demonstrating new technology to support future DoD space requirements. One of these flight programs will fly the first whole-spacecraft isolation system on a Taurus launch vehicle in January 1998 and another will demonstrate the first solar array with overall array specific power greater than 150W/Kg in the fall of 2002. This solar array is being developed for flight on the third New Millennium Program technology demonstration flight
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Distinctive Structural and Molecular Features of Myelinated Inhibitory Axons in Human Neocortex.
Numerous types of inhibitory neurons sculpt the performance of human neocortical circuits, with each type exhibiting a constellation of subcellular phenotypic features in support of its specialized functions. Axonal myelination has been absent among the characteristics used to distinguish inhibitory neuron types; in fact, very little is known about myelinated inhibitory axons in human neocortex. Here, using array tomography to analyze samples of neurosurgically excised human neocortex, we show that inhibitory myelinated axons originate predominantly from parvalbumin-containing interneurons. Compared to myelinated excitatory axons, they have higher neurofilament and lower microtubule content, shorter nodes of Ranvier, and more myelin basic protein (MBP) in their myelin sheath. Furthermore, these inhibitory axons have more mitochondria, likely to sustain the high energy demands of parvalbumin interneurons, as well as more 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP), a protein enriched in the myelin cytoplasmic channels that are thought to facilitate the delivery of nutrients from ensheathing oligodendrocytes. Our results demonstrate that myelinated axons of parvalbumin inhibitory interneurons exhibit distinctive features that may support the specialized functions of this neuron type in human neocortical circuits
Sexual Harassment and Australian Registered Nurses
Using a multi-method approach, this thesis examines sex-based and sexual harassment as perceived and experienced by Australian Registered Nurses (RN). The first phase of the research was a broadly based, exploratory survey questionnaire which served as a foundation for the second and third phases of the study. This initial phase and its analysis focused on the frequency and kinds of harassment the Registered Nurses described, as well as their responses and the affects of the harassment on them personally and professionally. ... The second phase of the study involved sixteen in-depth interviews that focused on how Registered Nurses acquire or process knowledge about harassment and how this knowledge is personally and socially reproduced. That is to say, how these RNs come to 'see' and 'understand' harassment; come to recognise harassment, label it, deal with it and interpret their action or inaction when confronted with it
B16: Chikungunya Virus Time Course Infection of Human Macrophages
Chikungunya virus (CHIKV) is an Alphavirus spread by Aedes spp. mosquitoes and is responsible for infecting 1.1 million people per year worldwide, including a large epidemic in the western hemisphere in 2014-2015. During the body’s immune response to CHIKV, human macrophages become infected after phagocytosis of CHIKV and undergo induced apoptosis, catalyzing the virus spread in the body. It is presently unclear what macrophage genes, functions, and intracellular signaling pathways are impacted during the early, intermediate, and late stages of CHIKV infection. Therefore we quantified the transcriptional response of human macrophage cells infected with CHIKV at two different timepoints
Novel Missions for Next Generation Microsatellites: The Results of a Joint AFRL/JPL Study
The development of technologies for miniature, low-mass, high density components and of systems that efficiently utilize these teclmologies has enabled a path to the next generation of highly capable microsatellites in the range of 10 - 100-kg. The characteristics and capabilities of this emerging class of satellites are briefly described. These satellites have the potential for revolutionizing space missions owing to their small size, low cost, significant capability, and good return on investment. This paper documents conceptual microsatellite mission scenarios examined in a collaborative effort between the Air Force Research Laboratory (AFRL) and the Jet Propulsion Laboratory of the California Institute of Technology (JPL). Six areas of mutual interest were selected from an initial set of about 30 microsatellite mission areas. Each of the selected areas was examined in more depth. The concepts explored include a remote sensing microsatellite, an on-orbit servicing microsatellite, a micronavigation and communication system, an adjunct microsatellite, and two distributed microsatellite systems; one for surveillance and one for space weather and physics observations. These missions are described briefly. A unique characteristic of these microsatellites, exploited in some of the mission scenarios, is the potential for low cost and rapid launch using non-traditional methods. One method examined involves using air-to-space missile technology
High Contrast Vacuum Nuller Testbed (VNT) Contrast, Performance and Null Control
Herein we report on our contrast assessment and the development, sensing and control of the Vacuum Nuller Testbed to realize a Visible Nulling Coronagraphy (VNC) for exoplanet detection and characterization. Tbe VNC is one of the few approaches that works with filled, segmented and sparse or diluted-aperture telescope systems. It thus spans a range of potential future NASA telescopes and could be flown as a separate instrument on such a future mission. NASA/Goddard Space Flight Center has an established effort to develop VNC technologies, and an incremental sequence of testbeds to advance this approach and its critical technologies. We discuss the development of the vacuum Visible Nulling Coronagraph testbed (VNT). The VNT is an ultra-stable vibration isolated testbed that operates under closed-loop control within a vacuum chamber. It will be used to achieve an incremental sequence of three visible-light nulling milestones with sequentially higher contrasts of 10(exp 8), 10(exp 9) and ideally 10(exp 10) at an inner working angle of 2*lambda/D. The VNT is based on a modified Mach-Zehnder nulling interferometer, with a "W" configuration to accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters. We discuss the laboratory results, optical configuration, critical technologies and the null sensing and control approach
EV Financing Options for Low-to-Moderate Income Individuals in Columbus, OH
Course Code: AEDECON 4567Through the assessment of existing electric vehicle (EV) equity programs, this report aims to provide Smart Columbus with policy options that will help increase adoption of EVs in low- to moderate-income (LMI) households in central Ohio through financing for personal vehicle ownership/lease. Our research uses key informant interviews and EV equity program websites and reports to draw comparisons with the capacity for the City of Columbus to adopt similar program components. We recommend that Smart Columbus consider developing a program to provide low-interest loans and grants as a financing option for an EV equity program in central Ohio. We also propose a structural outline for a five-step program that we recommend Smart Columbus adopt in pursuit of an EV equity program. Finally, we recommend two ways Smart Columbus can engage with the LMI community to alleviate barriers to EV adoption. These steps are to (1) create a financial literacy course in the program's application process (2) develop a set of key performance indicators to measure both environmental and social impacts within LMI communities.Academic Major: City and Regional PlanningAcademic Major: Environment, Economy, Development, and Sustainabilit
2D/3D Visual Tracker for Rover Mast
A visual-tracker computer program controls an articulated mast on a Mars rover to keep a designated feature (a target) in view while the rover drives toward the target, avoiding obstacles. Several prior visual-tracker programs have been tested on rover platforms; most require very small and well-estimated motion between consecutive image frames a requirement that is not realistic for a rover on rough terrain. The present visual-tracker program is designed to handle large image motions that lead to significant changes in feature geometry and photometry between frames. When a point is selected in one of the images acquired from stereoscopic cameras on the mast, a stereo triangulation algorithm computes a three-dimensional (3D) location for the target. As the rover moves, its body-mounted cameras feed images to a visual-odometry algorithm, which tracks two-dimensional (2D) corner features and computes their old and new 3D locations. The algorithm rejects points, the 3D motions of which are inconsistent with a rigid-world constraint, and then computes the apparent change in the rover pose (i.e., translation and rotation). The mast pan and tilt angles needed to keep the target centered in the field-of-view of the cameras (thereby minimizing the area over which the 2D-tracking algorithm must operate) are computed from the estimated change in the rover pose, the 3D position of the target feature, and a model of kinematics of the mast. If the motion between the consecutive frames is still large (i.e., 3D tracking was unsuccessful), an adaptive view-based matching technique is applied to the new image. This technique uses correlation-based template matching, in which a feature template is scaled by the ratio between the depth in the original template and the depth of pixels in the new image. This is repeated over the entire search window and the best correlation results indicate the appropriate match. The program could be a core for building application programs for systems that require coordination of vision and robotic motion
The impact of the UK soft drink industry levy on the soft drink marketplace, 2017–2020: An interrupted time series analysis with comparator series
Background: In April 2018, the UK government implemented a levy on soft drinks importers and manufacturers, tiered according to the amount of sugar in drinks. The stated aim was to encourage manufacturers to reduce sugar and portion sizes. Previous evidence suggests that the policy has been successful in reducing sugar in drinks in the short-term since implementation, but their sustained effects have not been explored. This study aimed to assess the impact of the soft drink industry levy (SDIL) on sugar levels, price, portion size and use of non-sugar sweeteners in the medium-term. Methods and findings: Product data from 30 November 2017 to 14 March 2020 from one major UK retail supermarket were analysed (112,452 observations, 126 weekly time points). We used interrupted time series analysis, to assess the impact of the soft-drink industry levy (SDIL) on levy-eligible soft drinks, with exempt drinks (i.e. 100% fruit juices, milks, flavoured milks) acting as a comparator series. At the point of implementation of the SDIL (April 2018) there was a step change in the proportion of eligible drinks with sugar content below the SDIL levy threshold (5g per 100ml) (+0.08, 95%CI: +0.04, +0.12), with a similar sized decrease in the proportion in the highest levy category (> = 8g sugar per 100ml) (-0.06, 95%CI: -0.10, -0.03). Between April 2018 and March 2020, the proportion of eligible drinks below the SDIL levy threshold continued to gradually increase (p = 0.003), while those in the highest levy category decreased (p = 0.007). There was a step change in price of eligible drinks in the higher levy category at the point of implementation of +£0.049 (95%CI: +£0.034, +£0.065) per 100mL (for comparison, the levy is set at £0.024 per 100mL for this group). Trends in price for the high levy category were not altered by the SDIL. In the no levy category, there was a step change in price at the implementation (+£0.012 per 100mL, 95%CI: +£0.008, +£0.023), followed by a second step change in October 2018 (-£0.018p per 100mL, 95%CI: -£0.033, -£0.001p). The volume of products in the higher levy group decreased at the time of the implementation (-305mL on average including multipacks, 95%CI: -511, -99). The change in trend for the product volume of drinks in the higher levy group between April 2018 and March 2020 was in the increasing direction (+704mL per year, 95%CI: -95, 1504), but it did not meet our threshold for statistical significance (p = 0.084). There were no changes observed in the volume of lower levy drinks or no levy drinks. There was a step change in the proportion of drinks with non-sugar sweeteners at the implementation of the SDIL (+0.04, 95%CI: +0.02, +0.06). Conclusion: These results suggest that the SDIL was successful in [1] producing reductions in sugar levels that were maintained over the medium term up to March 2020 and [2] a reduction in product volume for higher tier drinks that may be diminishing over time. Our results also show that the SDIL was associated with a maintained price differential between high and low sugar drinks
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