1,204 research outputs found

    Development of a Portfolio Management Approach with Case Study of the NASA Airspace Systems Program

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    A portfolio management approach was developed for the National Aeronautics and Space Administration s (NASA s) Airspace Systems Program (ASP). The purpose was to help inform ASP leadership regarding future investment decisions related to its existing portfolio of advanced technology concepts and capabilities (C/Cs) currently under development and to potentially identify new opportunities. The portfolio management approach is general in form and is extensible to other advanced technology development programs. It focuses on individual C/Cs and consists of three parts: 1) concept of operations (con-ops) development, 2) safety impact assessment, and 3) benefit-cost-risk (B-C-R) assessment. The first two parts are recommendations to ASP leaders and will be discussed only briefly, while the B-C-R part relates to the development of an assessment capability and will be discussed in greater detail. The B-C-R assessment capability enables estimation of the relative value of each C/C as compared with all other C/Cs in the ASP portfolio. Value is expressed in terms of a composite weighted utility function (WUF) rating, based on estimated benefits, costs, and risks. Benefit utility is estimated relative to achieving key NAS performance objectives, which are outlined in the ASP Strategic Plan.1 Risk utility focuses on C/C development and implementation risk, while cost utility focuses on the development and implementation portions of overall C/C life-cycle costs. Initial composite ratings of the ASP C/Cs were successfully generated; however, the limited availability of B-C-R information, which is used as inputs to the WUF model, reduced the meaningfulness of these initial investment ratings. Development of this approach, however, defined specific information-generation requirements for ASP C/C developers that will increase the meaningfulness of future B-C-R ratings

    Technical Challenges Associated with In-Air Wingtip Docking of Aircraft in Forward Flight

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    Autonomous in-air wingtip docking of aircraft offers significant opportunity for system level performance gains for numerous aircraft applications. Several of the technical challenges facing wingtip docking of fixed-wing aircraft are addressed in this paper, including: close proximity aerodynamic coupling; mechanisms and operations for robust docking; and relative state estimation methods. A simulation framework considering the aerodynamics, rigid-body dynamics, and vehicle controls is developed and used to perform docking sensitivity studies for a system of two 5.5% scale NASA Generic Transport Model aircraft. Additionally, proof of- concept testing of a candidate docking mechanism designed to move the primary wingtip vortex inboard suggests the viability of such an approach for achieving robust docking

    Genetic Structure of Faucet Snail, Bithynia tentaculata Populations in North America, Based on Microsatellite Markers

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    Bithynia tentaculata is believed to have been extirpated from North America during the last glacial maximum. It was reintroduced into North America via the Great Lakes basin in the 1800’s and has recently been expanding its geographic range. This snail serves as intermediate host for three trematodes that cause extensive recurring morbidity and mortality events in migratory water birds along the Mississippi River. Using twelve microsatellite loci for ~200 individual snails from 11populations in North America and Europe, we examined one of the three major geographic regions from which founding populations into the Great Lakes typically originate. Our data supports a single colonization of North America into the Great Lakes Basin followed by subsequent introduction events from the Great Lakes to other large watersheds in North America. However, additional watersheds in Europe require sampling to confirm this result. No populations with genetic signatures indicative of North American glacial relics were found. The initial invasion of North America was likely not from the Ponto-Caspian basin, the usual source of freshwater invasive species to the Laurentian Great Lake

    Ca2+/Calmodulin-Dependent Kinase Kinase α Is Expressed by Monocytic Cells and Regulates the Activation Profile

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    Macrophages are capable of assuming numerous phenotypes in order to adapt to endogenous and exogenous challenges but many of the factors that regulate this process are still unknown. We report that Ca2+/calmodulin-dependent kinase kinase α (CaMKKα) is expressed in human monocytic cells and demonstrate that its inhibition blocks type-II monocytic cell activation and promotes classical activation. Affinity chromatography with paramagnetic beads isolated an approximately 50 kDa protein from nuclear lysates of U937 human monocytic cells activated with phorbol-12-myristate-13-acetate (PMA). This protein was identified as CaMKKα by mass spectrometry and Western analysis. The function of CaMKKα in monocyte activation was examined using the CaMKKα inhibitors (STO-609 and forskolin) and siRNA knockdown. Inhibition of CaMKKα, enhanced PMA-dependent CD86 expression and reduced CD11b expression. In addition, inhibition was associated with decreased translocation of CaMKKα to the nucleus. Finally, to further examine monocyte activation profiles, TNFα and IL-10 secretion were studied. CaMKKα inhibition attenuated PMA-dependent IL-10 production and enhanced TNFα production indicating a shift from type-II to classical monocyte activation. Taken together, these findings indicate an important new role for CaMKKα in the differentiation of monocytic cells

    Benefit Assessment for Metroplex Tactical Runway Configuration Management (mTRCM) in a Simulated Environment

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    The System-Oriented Runway Management (SORM) concept is a collection of capabilities focused on a more efficient use of runways while considering all of the factors that affect runway use. Tactical Runway Configuration Management (TRCM), one of the SORM capabilities, provides runway configuration and runway usage recommendations, and monitoring the active runway configuration for suitability given existing factors. This report focuses on the metroplex environment, with two or more proximate airports having arrival and departure operations that are highly interdependent. The myriad of factors that affect metroplex opeations require consideration in arriving at runway configurations that collectively best serve the system as a whole. To assess the metroplex TRCM (mTRCM) benefit, the performance metrics must be compared with the actual historical operations. The historical configuration schedules can be viewed as the schedules produced by subject matter experts (SMEs), and therefore are referred to as the SMEs' schedules. These schedules were obtained from the FAA's Aviation System Performance Metrics (ASPM) database; this is the most representative information regarding runway configuration selection by SMEs. This report focused on a benefit assessment of total delay, transit time, and throughput efficiency (TE) benefits using the mTRCM algorithm at representative volumes for today's traffic at the New York metroplex (N90)

    A prospective safety and feasibility study of metered cryospray for patients with chronic bronchitis in COPD

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    BACKGROUND: No currently approved intervention counteracts airway metaplasia and mucus hypersecretion of Chronic Bronchitis (CB) in COPD. Metered Cryospray (MCS) delivering liquid nitrogen (LN2) to the tracheobronchial airways ablates abnormal epithelium and facilitates healthy mucosal regeneration. The objective of this study was to evaluate the feasibility, efficacy and safety of MCS in CB. METHODS: Patients with a FEV1, 30-80% of expected, taking optimal medication were recruited. Primary outcomes: feasibility - completion of treatments; efficacy - 3-month change in St George's Respiratory Questionnaire (SGRQ); safety - incidence of adverse events (AEs). SECONDARY OUTCOMES: lung function, exercise capacity, additional patient-reported outcomes (PROs). RESULTS: 35 patients, 19 male/16 female, aged 47-76 years, GOLD grade I (3), II (10) and III (22), underwent staggered LN2 treatments to the tracheobronchial tree.34 patients completed three treatments, each lasting 34·3±12·1 min, separated by 4-6 weeks: one withdrew after the first treatment. Approximately 1800 doses of MCS were delivered.Clinically meaningful improvements in PROs were observed at 3-months; ΔSGRQ -6·4 [95% CI -11.4, -1.3; p=0·01], COPD Assessment Test (CAT) -3·8 [95% CI -6.4, -1.3; p<0·01] and Leicester Cough Questionnaire (LCQ) 21·6 [95% CI 7.3, 35.9; p<0·01]. CAT changes were durable to 6-months (-3·4 [95% CI -5.9, -0.9; p=0·01]), SGRQ and LCQ to 9-months (-6·9 [95% CI -13.0, -0.9; p=0·03] and 13·4 [95% 2.1, 24.6; p=0·02], respectively).At 12-months, 14 serious AEs were recorded in 11 (31·4%) subjects, 6 moderate (43%) and 8 severe (57%). 9 were respiratory-related: 6 exacerbations of COPD, 2 pneumonias, and 1, increased coughing, recovered without sequelae. None were serious device or procedure-related AEs. CONCLUSION: MCS is safe, feasible and associated with clinically meaningful improvements in multidimensional PROs

    Projected Demand and Potential Impacts to the National Airspace System of Autonomous, Electric, On-Demand Small Aircraft

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    Electric propulsion and autonomy are technology frontiers that offer tremendous potential to achieve low operating costs for small-aircraft. Such technologies enable simple and safe to operate vehicles that could dramatically improve regional transportation accessibility and speed through point-to-point operations. This analysis develops an understanding of the potential traffic volume and National Airspace System (NAS) capacity for small on-demand aircraft operations. Future demand projections use the Transportation Systems Analysis Model (TSAM), a tool suite developed by NASA and the Transportation Laboratory of Virginia Polytechnic Institute. Demand projections from TSAM contain the mode of travel, number of trips and geographic distribution of trips. For this study, the mode of travel can be commercial aircraft, automobile and on-demand aircraft. NASA's Airspace Concept Evaluation System (ACES) is used to assess NAS impact. This simulation takes a schedule that includes all flights: commercial passenger and cargo; conventional General Aviation and on-demand small aircraft, and operates them in the simulated NAS. The results of this analysis projects very large trip numbers for an on-demand air transportation system competitive with automobiles in cost per passenger mile. The significance is this type of air transportation can enhance mobility for communities that currently lack access to commercial air transportation. Another significant finding is that the large numbers of operations can have an impact on the current NAS infrastructure used by commercial airlines and cargo operators, even if on-demand traffic does not use the 28 airports in the Continental U.S. designated as large hubs by the FAA. Some smaller airports will experience greater demand than their current capacity allows and will require upgrading. In addition, in future years as demand grows and vehicle performance improves other non-conventional facilities such as short runways incorporated into shopping mall or transportation hub parking areas could provide additional capacity and convenience

    The Spin of Holographic Electrons at Nonzero Density and Temperature

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    We study the Green's function of a gauge invariant fermionic operator in a strongly coupled field theory at nonzero temperature and density using a dual gravity description. The gravity model contains a charged black hole in four dimensional anti-de Sitter space and probe charged fermions. In particular, we consider the effects of the spin of these probe fermions on the properties of the Green's function. There exists a spin-orbit coupling between the spin of an electron and the electric field of a Reissner-Nordstrom black hole. On the field theory side, this coupling leads to a Rashba like dispersion relation. We also study the effects of spin on the damping term in the dispersion relation by considering how the spin affects the placement of the fermionic quasinormal modes in the complex frequency plane in a WKB limit. An appendix contains some exact solutions of the Dirac equation in terms of Heun polynomials.Comment: 27 pages, 11 figures; v2: minor changes, published versio

    Caregiver‐reported clinical characteristics and the burden associated with Kabuki syndrome

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    Publisher's version (útgefin grein)Kabuki syndrome is a genetic disorder that can affect multiple body systems and manifest as congenital abnormalities and both developmental and socio-emotional delays. The condition is largely unknown by most primary care physicians and has no available treatment other than symptomatic management. This research sought to obtain caregiver-reported data about the experience of living with and caring for someone with Kabuki syndrome to fill a gap in the available literature. Fifty-seven caregivers participated in an online survey and reported that Kabuki syndrome affected their children in a wide variety of ways, including a high frequency of visits to various healthcare professionals. Caregivers reported their child experienced problems with hearing, eating, eyes, mouth, immune system, anxiety, depression, autism, teeth, joints, seizures, kidneys, and heart. Caregivers also described the challenges of caring for someone with Kabuki syndrome, including an impact on emotional well-being and the ability to work outside the home. This unique research characterizes the caregiver experience of living with and caring for someone with Kabuki syndrome, both through observed manifestations of Kabuki syndrome in their own children and their experience managing their treatment. Additional research is needed to investigate the patient experience of living with Kabuki syndrome.Rene King, President & Founder, All Things Kabuki Inc. was essential to participant recruitment and the overall success of this study. Siobhan McDonald from Endpoint Outcomes assisted with recruitment and survey administration. Caitlin Pohl from Endpoint Outcomes contributed to the design of the study, survey administration, and data analysis. Christina Theodore‐Oklota is employed by Ultragenyx Pharmaceutical Inc. who funded this research. Deborah Hartman and Deborah Hoffman were employed by Takeda Pharmaceuticals at the time this research was conducted. Chris Evans, Maggie Paulich, and Shayna Egan are employed by Endpoint Outcomes who was paid to conduct this research. Hans T. Björnsson is a consultant for Millennium Pharmaceuticals.Peer Reviewe
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