NASA/RAE collaboration on nonlinear control using the F-8C digital fly-by-wire aircraft

Design procedures are reviewed for variable integral control to optimize response (VICTOR) algorithms and results of preliminary flight tests are presented. The F-8C aircraft is operated in the remotely augmented vehicle (RAV) mode, with the control laws implemented as FORTRAN programs on a ground-based computer. Pilot commands and sensor information are telemetered to the ground, where the data are processed to form surface commands which are then telemetered back to the aircraft. The RAV mode represents a singlestring (simplex) system and is therefore vulnerable to a hardover since comparison monitoring is not possible. Hence, extensive error checking is conducted on both the ground and airborne computers to prevent the development of potentially hazardous situations. Experience with the RAV monitoring and validation procedures is described

OGO-6 gas-surface energy transfer experiment

The kinetic energy flux of the upper atmosphere was analyzed using OGO-6 data. Energy transfer between 10 microwatts/sq cm and 0.1 W/sq cm was measured by short-term frequency changes of temperature-sensitive quartz crystals used in the energy transfer probe. The condition of the surfaces was continuously monitored by a quartz crystal microbalance to determine the effect surface contamination had on energy accommodation. Results are given on the computer analysis and laboratory tests performed to optimize the operation of the energy transfer probe. Data are also given on the bombardment of OGO-6 surfaces by high energy particles. The thermoelectrically-cooled quartz crystal microbalance is described in terms of its development and applications

“It gave me something big in my life to wonder and think about which took over the space … and not MS”: Managing well-being in multiple sclerosis through art-making

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2014 Informa UK Ltd.Background and aim: Individuals living with Multiple Sclerosis (MS) often face progressive loss of function, uncertainty and disruption to self-image and valued roles. Previous studies show that creative self-expression is valued by some people living with long-term illness, yet its meaning for people living with MS is unclear. This research study explored the meanings of leisure-based visual art-making for people living with MS. Method: This qualitative study followed guidelines for Interpretative Phenomenological Analysis (IPA). Single semi-structured interviews were conducted with five adults (2 males; 3 females; 40–65 years), recruited from MS Ireland. Findings: Participants valued art-making for contributing to a more satisfying way of life; for filling occupational voids and using time well. Deep immersion offered respite from worry about illness. Creative classes offered social camaraderie and opportunities for learning and development. Art-making processes and products were highly affirmative, increasing emotional well-being and promoting self-worth. Most felt that they expressed valued aspects of self through their art. Art-making appeared to assist with identity maintenance, accommodating functional losses associated with MS whilst opening “new doors”. Conclusion: Art-making offered a multi-faceted means of supporting identity and increasing fulfilment in lives that were restricted in many ways by MS

The Nearby and Extremely Metal-Poor Galaxy CGCG 269-049

We present Hubble Space Telescope (HST) and Spitzer Space Telescope images and photometry of the extremely metal-poor (Z = 0.03 Z_sol) blue dwarf galaxy CGCG 269-049. The HST images reveal a large population of red giant and asymptotic giant branch stars, ruling out the possibility that the galaxy has recently formed. From the magnitude of the tip of the red giant branch, we measure a distance to CGCG 269-049 of only 4.9 +/- 0.4 Mpc. The spectral energy distribution of the galaxy between ~3.6 - 70 microns is also best fitted by emission from predominantly ~10 Gyr old stars, with a component of thermal dust emission having a temperature of 52 +/- 10 K. The HST and Spitzer photometry indicate that more than 60% of CGCG 269-049's stellar mass consists of stars ~10 Gyr old, similar to other local blue dwarf galaxies. Our HST H-alpha image shows no evidence of a supernova-driven outflow that could be removing metals from the galaxy, nor do we find evidence that such outflows occurred in the past. Taken together with CGCG 269-049's large ratio of neutral hydrogen mass to stellar mass (~10), these results are consistent with recent simulations in which the metal deficiency of local dwarf galaxies results mainly from inefficient star formation, rather than youth or the escape of supernova ejecta.Comment: 35 Pages, 7 Figures, accepted for publication in ApJ; new version corrects errors in Table 1, Figure 3, and related calculations in tex

Search for antiproton decay at the Fermilab Antiproton Accumulator

A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on thirteen antiproton decay modes. The results include the first explicit experimental limits on the muonic decay modes of the antiproton, and the first limits on the decay modes e- gamma gamma, and e- omega. The most stringent limit is for the decay mode pbar-> e- gamma. At 90% C.L. we find that tau/B(pbar-> e- gamma) > 7 x 10^5 yr. The most stringent limit for decay modes with a muon in the final state is for the decay pbar-> mu- gamma. At 90% C.L. we find that tau/B(pbar-> mu- gamma) > 5 x 10^4 yr.Comment: 20 pages, 8 figures. Submitted to Phys. Rev. D. Final results on 13 channels (was 15) are presente

Poststroke Trajectories: The Process of Recovery Over the Longer Term Following Stroke

We adopted a grounded theory approach to explore the process of recovery experienced by stroke survivors over the longer term who were living in the community in the United Kingdom, and the interacting factors that are understood to have shaped their recovery trajectories. We used a combination of qualitative methods. From the accounts of 22 purposively sampled stroke survivors, four different recovery trajectories were evident: (a) meaningful recovery, (b) cycles of recovery and decline, (c) ongoing disruption, (d) gradual, ongoing decline. Building on the concept of the illness trajectory, our findings demonstrate how multiple, interacting factors shape the process and meaning of recovery over time. Such factors included conception of recovery and meanings given to the changing self, the meanings and consequences of health and illness experiences across the life course, loss, sense of agency, and enacting relationships. Awareness of the process of recovery will help professionals better support stroke survivors

Practical Methods for Continuous Gravitational Wave Detection using Pulsar Timing Data

Gravitational Waves (GWs) are tiny ripples in the fabric of space-time predicted by Einstein's General Relativity. Pulsar timing arrays (PTAs) are well poised to detect low frequency ($10^{-9}$ -- $10^{-7}$ Hz) GWs in the near future. There has been a significant amount of research into the detection of a stochastic background of GWs from supermassive black hole binaries (SMBHBs). Recent work has shown that single continuous sources standing out above the background may be detectable by PTAs operating at a sensitivity sufficient to detect the stochastic background. The most likely sources of continuous GWs in the pulsar timing frequency band are extremely massive and/or nearby SMBHBs. In this paper we present detection strategies including various forms of matched filtering and power spectral summing. We determine the efficacy and computational cost of such strategies. It is shown that it is computationally infeasible to use an optimal matched filter including the poorly constrained pulsar distances with a grid based method. We show that an Earth-term-matched filter constructed using only the correlated signal terms is both computationally viable and highly sensitive to GW signals. This technique is only a factor of two less sensitive than the computationally unrealizable optimal matched filter and a factor of two more sensitive than a power spectral summing technique. We further show that a pairwise matched filter, taking the pulsar distances into account is comparable to the optimal matched filter for the single template case and comparable to the Earth-term-matched filter for many search templates. Finally, using simulated data optimal quality, we place a theoretical minimum detectable strain amplitude of $h>2\times 10^{-15}$ from continuous GWs at frequencies on the order $\sim1/T_{\rm obs}$.Comment: submitted to Ap

Going beyond defining: Preschool educators\u27 use of knowledge in their pedagogical reasoning about vocabulary instruction

Previous research investigating both the knowledge of early childhood educators and the support for vocabulary development present in early childhood settings has indicated that both educator knowledge and enacted practice are less than optimal, which has grave implications for children\u27s early vocabulary learning and later reading achievement. Further, the nature of the relationship between educators\u27 knowledge and practice is unclear, making it difficult to discern the best path towards improved knowledge, practice, and children\u27s vocabulary outcomes. The purpose of the present study was to add to the existing literature by using stimulated recall interviews and a grounded approach to examine how 10 preschool educators used their knowledge to made decisions about their moment-to-moment instruction in support of children\u27s vocabulary development. Results indicate that educators were thinking in highly context-specific ways about their goals and strategies for supporting vocabulary learning, taking into account important knowledge of their instructional history with children and of the children themselves to inform their decision making in the moment. In addition, they reported thinking about research-based goals and strategies for supporting vocabulary learning that went beyond simply defining words for children. Implications for research and professional development are discussed

A search for antiproton decay at the Fermilab Antiproton Accumulator

We report on the search for anti-proton decay at the Fermilab Antiproton Accumulator Ring. Experiment 868 (APEX) was designed to search for two-body p̄ decay modes containing an electron in the final state (→e+X)(p̄→e+X) and to conduct an exploratory search for decays with a muon in the final state (→μ+X).(p̄→μ+X). Data were taken for three months in the Spring of 1995. Preliminary results yield lower limits on /BRτp̄/BR in the range of 105–106105–106 years for selected channels having an electron in the final state, improving on previous results by approximately 3 orders of magnitude. Additionally, we report the first preliminary results for the →μγp̄→μγ and →μπ0p̄→μπ0 decay channels. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87906/2/419_1.pd