Flight Acoustic Testing and For the Rotorcraft Noise Data Acquisition Model (RNM)

NASA Technical Reports Server (NTRS)

Burley, Casey L.; Smith, Charles D.; Conner, David A.

2006-01-01

Two acoustic flight tests have been conducted on a remote test range at Eglin Air Force Base in the panhandle of Florida. The first was the "Acoustics Week" flight test conducted in September 2003. The second was the NASA Heavy Lift Rotorcraft Acoustics Flight Test conducted in October-November 2005. Benchmark acoustic databases were obtained for a number of rotorcraft and limited fixed wing vehicles for a variety of flight conditions. The databases are important for validation of acoustic prediction programs such as the Rotorcraft Noise Model (RNM), as well as for the development of low noise flight procedures and for environmental impact assessments. An overview of RNM capabilities and a detailed description of the RNM/ART (Acoustic Repropagation Technique) process are presented. The RNM/ART process is demonstrated using measured acoustic data for the MD600N. The RNM predictions for a level flyover speed sweep show the highest SEL noise levels on the flight track centerline occurred at the slowest vehicle speeds. At these slower speeds, broadband noise content is elevated compared to noise levels obtained at the higher speeds. A descent angle sweep shows that, in general, ground noise levels increased with increasing descent rates. Vehicle orientation in addition to vehicle position was found to significantly affect the RNM/ART creation of source noise semi-spheres for vehicles with highly directional noise characteristics and only mildly affect those with weak acoustic directionality. Based on these findings, modifications are proposed for RNM/ART to more accurately define vehicle and rotor orientation.

Flight Acoustic Testing and Data Acquisition For the Rotor Noise Model (RNM)

NASA Technical Reports Server (NTRS)

Conner, David A.; Burley, Casey L.; Smith, Charles D.

2006-01-01

Two acoustic flight tests have been conducted on a remote test range at Eglin Air Force Base in the panhandle of Florida. The first was the Acoustics Week flight test conducted in September 2003. The second was the NASA Heavy Lift Rotorcraft Acoustics Flight Test conducted in October-November 2005. Benchmark acoustic databases were obtained for a number of rotorcraft and limited fixed wing vehicles for a variety of flight conditions. The databases are important for validation of acoustic prediction programs such as the Rotorcraft Noise Model (RNM), as well as for the development of low noise flight procedures and for environmental impact assessments. An overview of RNM capabilities and a detailed description of the RNM/ART (Acoustic Repropagation Technique) process are presented. The RNM/ART process is demonstrated using measured acoustic data for the MD600N. The RNM predictions for a level flyover speed sweep show the highest SEL noise levels on the flight track centerline occurred at the slowest vehicle speeds. At these slower speeds, broadband noise content is elevated compared to noise levels obtained at the higher speeds. A descent angle sweep shows that, in general, ground noise levels increased with increasing descent rates. Vehicle orientation in addition to vehicle position was found to significantly affect the RNM/ART creation of source noise semi-spheres for vehicles with highly directional noise characteristics and only mildly affect those with weak acoustic directionality. Based on these findings, modifications are proposed for RNM/ART to more accurately define vehicle and rotor orientation.

Testing an Emerging Paradigm in Migration Ecology Shows Surprising Differences in Efficiency between Flight Modes

PubMed Central

Duerr, Adam E.; Miller, Tricia A.; Lanzone, Michael; Brandes, Dave; Cooper, Jeff; O'Malley, Kieran; Maisonneuve, Charles; Tremblay, Junior; Katzner, Todd

2012-01-01

To maximize fitness, flying animals should maximize flight speed while minimizing energetic expenditure. Soaring speeds of large-bodied birds are determined by flight routes and tradeoffs between minimizing time and energetic costs. Large raptors migrating in eastern North America predominantly glide between thermals that provide lift or soar along slopes or ridgelines using orographic lift (slope soaring). It is usually assumed that slope soaring is faster than thermal gliding because forward progress is constant compared to interrupted progress when birds pause to regain altitude in thermals. We tested this slope-soaring hypothesis using high-frequency GPS-GSM telemetry devices to track golden eagles during northbound migration. In contrast to expectations, flight speed was slower when slope soaring and eagles also were diverted from their migratory path, incurring possible energetic costs and reducing speed of progress towards a migratory endpoint. When gliding between thermals, eagles stayed on track and fast gliding speeds compensated for lack of progress during thermal soaring. When thermals were not available, eagles minimized migration time, not energy, by choosing energetically expensive slope soaring instead of waiting for thermals to develop. Sites suited to slope soaring include ridges preferred for wind-energy generation, thus avian risk of collision with wind turbines is associated with evolutionary trade-offs required to maximize fitness of time-minimizing migratory raptors. PMID:22558166

Gravitropism and development of wild-type and starch-deficient mutants of Arabidopsis during spaceflight

NASA Technical Reports Server (NTRS)

Kiss, J. Z.; Katembe, W. J.; Edelmann, R. E.

1998-01-01

The "starch-statolith" hypothesis has been used by plant physiologists to explain the gravity perception mechanism in higher plants. In order to help resolve some of the controversy associated with ground-based research that has supported this theory, we performed a spaceflight experiment during the January 1997 mission of the Space Shuttle STS-81. Seedlings of wild-type (WT) Arabidopsis, two reduced-starch strains, and a starchless mutant were grown in microgravity and then given a gravity stimulus on a centrifuge. In terms of development in space, germination was greater than 90% for seeds in microgravity, and flight seedlings were smaller (60% in total length) compared to control plants grown on the ground and to control plants on a rotating clinostat. Seedlings grown in space had two structural features that distinguished them from the controls: a greater density of root hairs and an anomalous hypocotyl hook structure. However, the slower growth and morphological changes observed in the flight seedlings may be due to the effects of ethylene present in the spacecraft. Nevertheless, during the flight hypocotyls of WT seedlings responded to a unilateral 60 min stimulus provided by a 1-g centrifuge while those of the starch-deficient strains did not. Thus the strain with the greatest amount of starch responded to the stimulus given in flight and therefore, these data support the starch-statolith model for gravity sensing.

Testing an emerging paradigm in migration ecology shows surprising differences in efficiency between flight modes.

PubMed

Duerr, Adam E; Miller, Tricia A; Lanzone, Michael; Brandes, Dave; Cooper, Jeff; O'Malley, Kieran; Maisonneuve, Charles; Tremblay, Junior; Katzner, Todd

2012-01-01

To maximize fitness, flying animals should maximize flight speed while minimizing energetic expenditure. Soaring speeds of large-bodied birds are determined by flight routes and tradeoffs between minimizing time and energetic costs. Large raptors migrating in eastern North America predominantly glide between thermals that provide lift or soar along slopes or ridgelines using orographic lift (slope soaring). It is usually assumed that slope soaring is faster than thermal gliding because forward progress is constant compared to interrupted progress when birds pause to regain altitude in thermals. We tested this slope-soaring hypothesis using high-frequency GPS-GSM telemetry devices to track golden eagles during northbound migration. In contrast to expectations, flight speed was slower when slope soaring and eagles also were diverted from their migratory path, incurring possible energetic costs and reducing speed of progress towards a migratory endpoint. When gliding between thermals, eagles stayed on track and fast gliding speeds compensated for lack of progress during thermal soaring. When thermals were not available, eagles minimized migration time, not energy, by choosing energetically expensive slope soaring instead of waiting for thermals to develop. Sites suited to slope soaring include ridges preferred for wind-energy generation, thus avian risk of collision with wind turbines is associated with evolutionary trade-offs required to maximize fitness of time-minimizing migratory raptors.

Calcium metabolism before, during, and after a 3-mo spaceflight: kinetic and biochemical changes

NASA Technical Reports Server (NTRS)

Smith, S. M.; Wastney, M. E.; Morukov, B. V.; Larina, I. M.; Nyquist, L. E.; Abrams, S. A.; Taran, E. N.; Shih, C. Y.; Nillen, J. L.; Davis-Street, J. E.;

Forward flight of birds revisited. Part 1: aerodynamics and performance.

PubMed

Iosilevskii, G

2014-10-01

This paper is the first part of the two-part exposition, addressing performance and dynamic stability of birds. The aerodynamic model underlying the entire study is presented in this part. It exploits the simplicity of the lifting line approximation to furnish the forces and moments acting on a single wing in closed analytical forms. The accuracy of the model is corroborated by comparison with numerical simulations based on the vortex lattice method. Performance is studied both in tethered (as on a sting in a wind tunnel) and in free flights. Wing twist is identified as the main parameter affecting the flight performance-at high speeds, it improves efficiency, the rate of climb and the maximal level speed; at low speeds, it allows flying slower. It is demonstrated that, under most circumstances, the difference in performance between tethered and free flights is small.

Visual Odometry for Autonomous Deep-Space Navigation Project

NASA Technical Reports Server (NTRS)

Robinson, Shane; Pedrotty, Sam

2016-01-01

Autonomous rendezvous and docking (AR&D) is a critical need for manned spaceflight, especially in deep space where communication delays essentially leave crews on their own for critical operations like docking. Previously developed AR&D sensors have been large, heavy, power-hungry, and may still require further development (e.g. Flash LiDAR). Other approaches to vision-based navigation are not computationally efficient enough to operate quickly on slower, flight-like computers. The key technical challenge for visual odometry is to adapt it from the current terrestrial applications it was designed for to function in the harsh lighting conditions of space. This effort leveraged Draper Laboratory’s considerable prior development and expertise, benefitting both parties. The algorithm Draper has created is unique from other pose estimation efforts as it has a comparatively small computational footprint (suitable for use onboard a spacecraft, unlike alternatives) and potentially offers accuracy and precision needed for docking. This presents a solution to the AR&D problem that only requires a camera, which is much smaller, lighter, and requires far less power than competing AR&D sensors. We have demonstrated the algorithm’s performance and ability to process ‘flight-like’ imagery formats with a ‘flight-like’ trajectory, positioning ourselves to easily process flight data from the upcoming ‘ISS Selfie’ activity and then compare the algorithm’s quantified performance to the simulated imagery. This will bring visual odometry beyond TRL 5, proving its readiness to be demonstrated as part of an integrated system.Once beyond TRL 5, visual odometry will be poised to be demonstrated as part of a system in an in-space demo where relative pose is critical, like Orion AR&D, ISS robotic operations, asteroid proximity operations, and more.

Visual Odometry for Autonomous Deep-Space Navigation Project

NASA Technical Reports Server (NTRS)

Robinson, Shane; Pedrotty, Sam

2016-01-01

Autonomous rendezvous and docking (AR&D) is a critical need for manned spaceflight, especially in deep space where communication delays essentially leave crews on their own for critical operations like docking. Previously developed AR&D sensors have been large, heavy, power-hungry, and may still require further development (e.g. Flash LiDAR). Other approaches to vision-based navigation are not computationally efficient enough to operate quickly on slower, flight-like computers. The key technical challenge for visual odometry is to adapt it from the current terrestrial applications it was designed for to function in the harsh lighting conditions of space. This effort leveraged Draper Laboratory's considerable prior development and expertise, benefitting both parties. The algorithm Draper has created is unique from other pose estimation efforts as it has a comparatively small computational footprint (suitable for use onboard a spacecraft, unlike alternatives) and potentially offers accuracy and precision needed for docking. This presents a solution to the AR&D problem that only requires a camera, which is much smaller, lighter, and requires far less power than competing AR&D sensors. We have demonstrated the algorithm's performance and ability to process 'flight-like' imagery formats with a 'flight-like' trajectory, positioning ourselves to easily process flight data from the upcoming 'ISS Selfie' activity and then compare the algorithm's quantified performance to the simulated imagery. This will bring visual odometry beyond TRL 5, proving its readiness to be demonstrated as part of an integrated system. Once beyond TRL 5, visual odometry will be poised to be demonstrated as part of a system in an in-space demo where relative pose is critical, like Orion AR&D, ISS robotic operations, asteroid proximity operations, and more.

X-38 Experimental Controls Laws

NASA Technical Reports Server (NTRS)

Munday, Steve; Estes, Jay; Bordano, Aldo J.

2000-01-01

X-38 Experimental Control Laws X-38 is a NASA JSC/DFRC experimental flight test program developing a series of prototypes for an International Space Station (ISS) Crew Return Vehicle, often called an ISS "lifeboat." X- 38 Vehicle 132 Free Flight 3, currently scheduled for the end of this month, will be the first flight test of a modem FCS architecture called Multi-Application Control-Honeywell (MACH), originally developed by the Honeywell Technology Center. MACH wraps classical P&I outer attitude loops around a modem dynamic inversion attitude rate loop. The dynamic inversion process requires that the flight computer have an onboard aircraft model of expected vehicle dynamics based upon the aerodynamic database. Dynamic inversion is computationally intensive, so some timing modifications were made to implement MACH on the slower flight computers of the subsonic test vehicles. In addition to linear stability margin analyses and high fidelity 6-DOF simulation, hardware-in-the-loop testing is used to verify the implementation of MACH and its robustness to aerodynamic and environmental uncertainties and disturbances.

Neutron Spectroscopy for pulsed beams with frame overlap using a double time-of-flight technique

NASA Astrophysics Data System (ADS)

Harrig, K. P.; Goldblum, B. L.; Brown, J. A.; Bleuel, D. L.; Bernstein, L. A.; Bevins, J.; Harasty, M.; Laplace, T. A.; Matthews, E. F.

2018-01-01

A new double time-of-flight (dTOF) neutron spectroscopy technique has been developed for pulsed broad spectrum sources with a duty cycle that results in frame overlap, where fast neutrons from a given pulse overtake slower neutrons from previous pulses. Using a tunable beam at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory, neutrons were produced via thick-target breakup of 16 MeV deuterons on a beryllium target in the cyclotron vault. The breakup spectral shape was deduced from a dTOF measurement using an array of EJ-309 organic liquid scintillators. Simulation of the neutron detection efficiency of the scintillator array was performed using both GEANT4 and MCNP6. The efficiency-corrected spectral shape was normalized using a foil activation technique to obtain the energy-dependent flux of the neutron beam at zero degrees with respect to the incoming deuteron beam. The dTOF neutron spectrum was compared to spectra obtained using HEPROW and GRAVEL pulse height spectrum unfolding techniques. While the unfolding and dTOF results exhibit some discrepancies in shape, the integrated flux values agree within two standard deviations. This method obviates neutron time-of-flight spectroscopy challenges posed by pulsed beams with frame overlap and opens new opportunities for pulsed white neutron source facilities.

Could some aviation deep vein thrombosis be a form of decompression sickness?

PubMed

Buzzacott, Peter; Mollerlokken, Andreas

2016-10-01

Aviation deep vein thrombosis is a challenge poorly understood in modern aviation. The aim of the present project was to determine if cabin decompression might favor formation of vascular bubbles in commercial air travelers. Thirty commercial flights were taken. Cabin pressure was noted at take-off and at every minute following, until the pressure stabilized. These time-pressure profiles were imported into the statistics program R and analyzed using the package SCUBA. Greatest pressure differentials between tissues and cabin pressures were estimated for 20, 40, 60, 80 and 120 min half-time compartments. Time to decompress ranged from 11 to 47 min. The greatest drop in cabin pressure was from 1022 to 776 mBar, equivalent to a saturated diver ascending from 2.46 msw depth. Mean pressure drop in flights >2 h duration was 193 mBar, while mean pressure drop in flights <2 h was 165 mBar. The greatest drop in pressure over 1 min was 28 mBar. Over 30 commercial flights it was found that the drop in cabin pressure was commensurate with that found to cause bubbles in man. Both the US Navy and the Royal Navy mandate far slower decompression from states of saturation, being 1.7 and 1.9 mBar/min respectively. The median overall rate of decompression found in this study was 8.5 mBar/min, five times the rate prescribed for USN saturation divers. The tissues associated with hypobaric bubble formation are likely slower than those associated with bounce diving, with 60 min a potentially useful index.

Application of hybrid methodology to rotors in steady and maneuvering flight

NASA Astrophysics Data System (ADS)

Rajmohan, Nischint

Helicopters are versatile flying machines that have capabilities that are unparalleled by fixed wing aircraft, such as operating in hover, performing vertical takeoff and landing on unprepared sites. This makes their use especially desirable in military and search-and-rescue operations. However, modern helicopters still suffer from high levels of noise and vibration caused by the physical phenomena occurring in the vicinity of the rotor blades. Therefore, improvement in rotorcraft design to reduce the noise and vibration levels requires understanding of the underlying physical phenomena, and accurate prediction capabilities of the resulting rotorcraft aeromechanics. The goal of this research is to study the aeromechanics of rotors in steady and maneuvering flight using hybrid Computational Fluid Dynamics (CFD) methodology. The hybrid CFD methodology uses the Navier-Stokes equations to solve the flow near the blade surface but the effect of the far wake is computed through the wake model. The hybrid CFD methodology is computationally efficient and its wake modeling approach is nondissipative making it an attractive tool to study rotorcraft aeromechanics. Several enhancements were made to the CFD methodology and it was coupled to a Computational Structural Dynamics (CSD) methodology to perform a trimmed aeroelastic analysis of a rotor in forward flight. The coupling analyses, both loose and tight were used to identify the key physical phenomena that affect rotors in different steady flight regimes. The modeling enhancements improved the airloads predictions for a variety of flight conditions. It was found that the tightly coupled method did not impact the loads significantly for steady flight conditions compared to the loosely coupled method. The coupling methodology was extended to maneuvering flight analysis by enhancing the computational and structural models to handle non-periodic flight conditions and vehicle motions in time accurate mode. The flight test control angles were employed to enable the maneuvering flight analysis. The fully coupled model provided the presence of three dynamic stall cycles on the rotor in maneuver. It is important to mention that analysis of maneuvering flight requires knowledge of the pilot input control pitch settings, and the vehicle states. As the result, these computational tools cannot be used for analysis of loads in a maneuver that has not been duplicated in a real flight. This is a significant limitation if these tools are to be selected during the design phase of a helicopter where its handling qualities are evaluated in different trajectories. Therefore, a methodology was developed to couple the CFD/CSD simulation with an inverse flight mechanics simulation to perform the maneuver analysis without using the flight test control input. The methodology showed reasonable convergence in steady flight regime and control angles predictions compared fairly well with test data. In the maneuvering flight regions, the convergence was slower due to relaxation techniques used for the numerical stability. The subsequent computed control angles for the maneuvering flight regions compared well with test data. Further, the enhancement of the rotor inflow computations in the inverse simulation through implementation of a Lagrangian wake model improved the convergence of the coupling methodology.

Pressurized Structure Technology for UAVS

DTIC Science & Technology

2008-12-01

deficiencies of the UAVs just listed is to employ lighter-than-air or pressurized structure-based ( PSB ) technology. Basically, the UAV will be built such...that a considerable percentage of its weight is supported by or constructed from inflatable structures containing air or helium. PSB technology...neutral buoyancy will allow much slower flight speeds and increased maneuverability while expending little power. PSB airframes used in conjunction

A Turbine-powered UAV Controls Testbed

NASA Technical Reports Server (NTRS)

Motter, Mark A.; High, James W.; Guerreiro, Nelson M.; Chambers, Ryan S.; Howard, Keith D.

2007-01-01

The latest version of the NASA Flying Controls Testbed (FLiC) integrates commercial-off-the-shelf components including airframe, autopilot, and a small turbine engine to provide a low cost experimental flight controls testbed capable of sustained speeds up to 200 mph. The series of flight tests leading up to the demonstrated performance of the vehicle in sustained, autopiloted 200 mph flight at NASA Wallops Flight Facility's UAV runway in August 2006 will be described. Earlier versions of the FLiC were based on a modified Army target drone, AN/FQM-117B, developed as part of a collaboration between the Aviation Applied Technology Directorate at Fort Eustis, Virginia and NASA Langley Research Center. The newer turbine powered platform (J-FLiC) builds on the successes using the relatively smaller, slower and less expensive unmanned aerial vehicle developed specifically to test highly experimental flight control approaches with the implementation of C-coded experimental controllers. Tracking video was taken during the test flights at Wallops and will be available for presentation at the conference. Analysis of flight data from both remotely piloted and autopiloted flights will be presented. Candidate experimental controllers for implementation will be discussed. It is anticipated that flight testing will resume in Spring 2007 and those results will be included, if possible.

Mental rotation task in a pilot during and after pregnancy.

PubMed

Piccardi, Laura; Verde, Paola; Bianchini, Filippo; Morgagni, Fabio; Guariglia, Cecilia; Strollo, Felice

2013-10-01

Discordant findings have been reported about the change in pregnant women's cognitive test performance. Visuo-spatial abilities, which are crucial in terrestrial/flight navigation, could be influenced by hormonal variations. A 32-yr-old Italian Air Force pilot underwent a 2-D Mental Rotation Task (MRT) and hormonal assessment in the second trimester of pregnancy and 1 yr after delivery. Her performance was compared with that of two nonpregnant groups of women: one with flying experience and the other without. Estradiol and progesterone were significantly higher in pregnancy compared with postpartum, while testosterone was almost unchanged. During pregnancy, we observed a significant difference in the subject's response time compared with pilots (she was slower) and nonpilots (she was faster). One year after delivery, her performance was still better than the nonpilot group and was almost the same as the pilot group. Our data are consistent with an effect of pregnancy on visuo-spatial ability that can last for some time after delivery, even with the early recovery of the hormonal levels. MRT smoothly changed in our subject, supporting previous findings that women who are experts in flight navigation are less sensitive to hormonal fluctuations. In this case, visuospatial ability requiring effortful processing underwent variations during pregnancy and postpartum. Further studies are needed in order to confirm our observations in a wider population.

Sediment on Mars: settling faster, moving slower

NASA Astrophysics Data System (ADS)

Kuhn, N. J.

2013-12-01

Using empirical approaches developed on Earth to assess Martian hydrology based on conglomerates such as those found at Gale crater may deliver false results because Martian gravity potentially alters flow-sediment interaction compared to Earth. In this study, we report the results of our Mars Sedimentation Experiments (MarsSedEx I and II) which used settling tubes during reduced gravity flights in November 2012 (and scheduled for November 2013) on board Zero g's G-Force 1. The settling velocity data collected during the flights are compared to several models for terrestrial settling velocities. The results indicate that settling velocities on Mars are underestimated by up to 30 to 50%, depending on the selected model. As a consequence, transport distances of sediment particles increase by a similar proportion in a given flow. We suspect that the underestimation of settling velocity is caused by poor capture of flow hydraulics under reduced gravity. While MarsSedEx I (and II) results are only very preliminary, they indicate that applying empirically derived models for Earth to conglomerates such as those found at Garle crater to derive properties of surface runoff carries the risk of significantly misjudging flow depth and velocities. In the light of the potentially strong influence of topography on runoff generation on Mars, we may therefore end up looking for water in the wrong place.

Problems in analysis of data from muscles of rats flow in space

NASA Technical Reports Server (NTRS)

Tischler, Marc E.; Henriksen, Erik; Jacob, Stephan; Satarug, Soisungwan; Cook, Paul

1988-01-01

Comparison of hind-limb muscles of rats flown on Spacelab-3 or tail-traction-suspended showed that 11-17 h reloading postflight might have altered the results. Soleus atrophied; plantaris, gastrocnemius, and extensor digitorum longus grew slower; and tibialis anteiror grew normally. In both flight and simulated soleus and plantaris, higher tyrosine and greater glutamine/glutamate ratio indicated negative protein balance and increased glutamine production, respectively, relative to controls. Aspartate was lower in these muscles. Reloading generally decreased tyrosine, but increased aspartate and glutamine/glutamate. These data showed that 12 h of reloading after flight is characterized by reversal, to varying extents, of the effects of unloading.

Response of rat hindlimb muscles to 12 hours recovery from tail-cast suspension

NASA Technical Reports Server (NTRS)

Tischler, M. E.; Henriksen, E. J.; Jacob, S.; Jaspers, S. R.

1985-01-01

Previous work has shown a number of biochemical changes which accompany atrophy or reduced muscle growth in hindlimb of tail-casted, suspended rats. These results clearly show that altered muscle growth was due to changes in protein turnover. Accordingly, the rise in soleus tyrosine following unloading reflects the more negative protein balance. Other major changes we found included slower synthesis of glutamine as indicated by lower ratios of glutamine/glutamate and reduced levels of aspartate which coincide with slower aspartate and ammonia metabolism in vitro. In conjunction with the study of SL-3 rats, which were subjected to 12 h of post-flight gravity, a study of the effects of 12 h eight bearing on metabolism of 6-day unloaded hindlimb muscles was carried out.

Adapted ECC ozonesonde for long-duration flights aboard boundary-layer pressurised balloons

NASA Astrophysics Data System (ADS)

Gheusi, François; Durand, Pierre; Verdier, Nicolas; Dulac, François; Attié, Jean-Luc; Commun, Philippe; Barret, Brice; Basdevant, Claude; Clenet, Antoine; Derrien, Solène; Doerenbecher, Alexis; El Amraoui, Laaziz; Fontaine, Alain; Hache, Emeric; Jambert, Corinne; Jaumouillé, Elodie; Meyerfeld, Yves; Roblou, Laurent; Tocquer, Flore

2016-12-01

Since the 1970s, the French space agency CNES has developed boundary-layer pressurised balloons (BLPBs) with the capability to transport lightweight scientific payloads at isopycnic level and offer a quasi-Lagrangian sampling of the lower atmosphere over very long distances and durations (up to several weeks).

Electrochemical concentration cell (ECC) ozonesondes are widely used under small sounding balloons. However, their autonomy is limited to a few hours owing to power consumption and electrolyte evaporation. An adaptation of the ECC sonde has been developed specifically for long-duration BLPB flights. Compared to conventional ECC sondes, the main feature is the possibility of programming periodic measurement sequences (with possible remote control during the flight). To increase the ozonesonde autonomy, the strategy has been adopted of short measurement sequences (2-3 min) regularly spaced in time (e.g. every 15 min). The rest of the time, the sonde pump is turned off. Results of preliminary ground-based tests are first presented. In particular, the sonde was able to provide correct ozone concentrations against a reference UV-absorption ozone analyser every 15 min for 4 days. Then we illustrate results from 16 BLBP flights launched over the western Mediterranean during three summer field campaigns of the ChArMEx project (http://charmex.lsce.ipsl.fr): TRAQA in 2012, and ADRIMED and SAFMED in 2013. BLPB drifting altitudes were in the range 0.25-3.2 km. The longest flight lasted more than 32 h and covered more than 1000 km. Satisfactory data were obtained when compared to independent ozone measurements close in space and time. The quasi-Lagrangian measurements allowed a first look at ozone diurnal evolution in the marine boundary layer as well as in the lower free troposphere. During some flight segments, there was indication of photochemical ozone production in the marine boundary layer or even in the free troposphere, at rates ranging from 1 to 2 ppbv h -1, which is slower than previously found in the boundary layer over land in the same region.

Preliminary Study of Turbulence for a Lobed Body in Hypersonic Flight

DTIC Science & Technology

2013-02-22

physics. Modest improvements in numerical algorithms, particularly those for solving partial differential equations ( PDEs ), can now be fully...dramatically.[7] In slower speed flow fields, this energy is absorbed mostly in molecular translational and rotational modes, but for hypersonic...REFERENCES 1. Génin, F., Fryxell, B. and Menon, S., “Simulation of Detonation Propagation in Turbulent Gas- Solid Reactive Mixtures”, 41 st

Spaceflight effects on cultured embryonic chick bone cells

NASA Technical Reports Server (NTRS)

Landis, W. J.; Hodgens, K. J.; Block, D.; Toma, C. D.; Gerstenfeld, L. C.

2000-01-01

A model calcifying system of primary osteoblast cell cultures derived from normal embryonic chicken calvaria has been flown aboard the shuttle, Endeavour, during the National Aeronautics and Space Administration (NASA) mission STS-59 (April 9-20, 1994) to characterize unloading and other spaceflight effects on the bone cells. Aliquots of cells (approximately 7 x 10(6)) grown in Dulbecco's modified Eagle's medium (DMEM) + 10% fetal bovine serum (FBS) were mixed with microcarrier beads, inoculated into cartridge culture units of artificial hollow fiber capillaries, and carried on the shuttle. To promote cell differentiation, cartridge media were supplemented with 12.5 microg/ml ascorbate and 10 mM beta-glycerophosphate for varying time periods before and during flight. Four cartridges contained cells from 17-day-old embryos grown for 5 days in the presence of ascorbate prior to launch (defined as flight cells committed to the osteoblastic lineage) and four cartridges supported cells from 14-day-old embryos grown for 10 days with ascorbate before launch (uncommitted flight cells). Eight cartridges prepared in the same manner were maintained under normal gravity throughout the flight (control cells) and four additional identical cartridges under normal gravity were terminated on the day of launch (basal cells). From shuttle launch to landing, all cartridges were contained in closed hardware units maintaining 5% CO2, 37 degrees C, and media delivery at a rate of approximately 1.5 ml/6 h. During day 3 and day 5 of flight, duplicate aliquots of conditioned media and accumulated cell products were collected in both the flight and the control hardware units. At the mission end, comparisons among flight, basal, and control samples were made in cell metabolism, gene expression for type I collagen and osteocalcin, and ultrastructure. Both committed and uncommitted flight cells were metabolically active, as measured by glucose uptake and lactate production, at approximately the same statistical levels as control counterparts. Flight cells elaborated a less extensive extracellular matrix, evidenced by a reduced collagen gene expression and collagen protein appearance compared with controls. Osteocalcin was expressed by all cells, a result indicating progressive differentiation of both flight and control osteoblasts, but its message levels also were reduced in flight cells compared with ground samples. This finding suggested that osteoblasts subjected to flight followed a slower progression toward a differentiated function. The summary of data indicates that spaceflight, including microgravity exposure, demonstrably affects bone cells by down-regulating type I collagen and osteocalcin gene expression and thereby inhibiting expression of the osteogenic phenotype notably by committed osteoblasts. The information is important for insight into the response of bone cells to changes of gravity and of force in general.

Orthostatic Intolerance After ISS and Space Shuttle Missions.

PubMed

Lee, Stuart M C; Feiveson, Alan H; Stein, Sydney; Stenger, Michael B; Platts, Steven H

2015-12-01

Cardiovascular deconditioning apparently progresses with flight duration, resulting in a greater incidence of orthostatic intolerance following long-duration missions. Therefore, we anticipated that the proportion of astronauts who could not complete an orthostatic tilt test (OTT) would be higher on landing day and the number of days to recover greater after International Space Station (ISS) than after Space Shuttle missions. There were 20 ISS and 65 Shuttle astronauts who participated in 10-min 80° head-up tilt tests 10 d before launch, on landing day (R+0), and 3 d after landing (R+3). Fisher's Exact Test was used to compare the ability of ISS and Shuttle astronauts to complete the OTT. Cox regression was used to identify cardiovascular parameters associated with OTT completion and mixed model analysis was used to compare the change and recovery rates between groups. The proportion of astronauts who completed the OTT on R+0 (2 of 6) was less in ISS than in Shuttle astronauts (52 of 65). On R+3, 13 of 15 and 19 of 19 of the ISS and Shuttle astronauts, respectively, completed the OTT. An index comprised of stroke volume and diastolic blood pressure provided a good prediction of OTT completion and was altered by spaceflight similarly for both astronaut groups, but recovery was slower in ISS than in Shuttle astronauts. The proportion of ISS astronauts who could not complete the OTT on R+0 was greater and the recovery rate slower after ISS compared to Shuttle missions. Thus, mission planners and crew surgeons should anticipate the need to tailor scheduled activities and level of medical support to accommodate protracted recovery after long-duration microgravity exposures.

Computationally-Efficient Minimum-Time Aircraft Routes in the Presence of Winds

NASA Technical Reports Server (NTRS)

Jardin, Matthew R.

2004-01-01

A computationally efficient algorithm for minimizing the flight time of an aircraft in a variable wind field has been invented. The algorithm, referred to as Neighboring Optimal Wind Routing (NOWR), is based upon neighboring-optimal-control (NOC) concepts and achieves minimum-time paths by adjusting aircraft heading according to wind conditions at an arbitrary number of wind measurement points along the flight route. The NOWR algorithm may either be used in a fast-time mode to compute minimum- time routes prior to flight, or may be used in a feedback mode to adjust aircraft heading in real-time. By traveling minimum-time routes instead of direct great-circle (direct) routes, flights across the United States can save an average of about 7 minutes, and as much as one hour of flight time during periods of strong jet-stream winds. The neighboring optimal routes computed via the NOWR technique have been shown to be within 1.5 percent of the absolute minimum-time routes for flights across the continental United States. On a typical 450-MHz Sun Ultra workstation, the NOWR algorithm produces complete minimum-time routes in less than 40 milliseconds. This corresponds to a rate of 25 optimal routes per second. The closest comparable optimization technique runs approximately 10 times slower. Airlines currently use various trial-and-error search techniques to determine which of a set of commonly traveled routes will minimize flight time. These algorithms are too computationally expensive for use in real-time systems, or in systems where many optimal routes need to be computed in a short amount of time. Instead of operating in real-time, airlines will typically plan a trajectory several hours in advance using wind forecasts. If winds change significantly from forecasts, the resulting flights will no longer be minimum-time. The need for a computationally efficient wind-optimal routing algorithm is even greater in the case of new air-traffic-control automation concepts. For air-traffic-control automation, thousands of wind-optimal routes may need to be computed and checked for conflicts in just a few minutes. These factors motivated the need for a more efficient wind-optimal routing algorithm.

Rapid Mars transits with exhaust-modulated plasma propulsion

NASA Technical Reports Server (NTRS)

Chang-Diaz, Franklin R.; Braden, Ellen; Johnson, Ivan; Hsu, Michael M.; Yang, Tien Fang

1995-01-01

The operational characteristics of the Exhaust-Modulated Plasma Rocket are described. Four basic human and robotic mission scenarios to Mars are analyzed using numerical optimization techniques at variable specific impulse and constant power. The device is well suited for 'split-sprint' missions, allowing fast, one-way low-payload human transits of 90 to 104 days, as well as slower, 180-day, high-payload robotic precursor flights. Abort capabilities, essential for human missions, are also explored.

Hypoxia and flight performance of military instructor pilots in a flight simulator.

PubMed

Temme, Leonard A; Still, David L; Acromite, Michael T

2010-07-01

Military aircrew and other operational personnel frequently perform their duties at altitudes posing a significant hypoxia risk, often with limited access to supplemental oxygen. Despite the significant risk hypoxia poses, there are few studies relating it to primary flight performance, which is the purpose of the present study. Objective, quantitative measures of aircraft control were collected from 14 experienced, active duty instructor pilot volunteers as they breathed an air/nitrogen mix that provided an oxygen partial pressure equivalent to the atmosphere at 18,000 ft (5486.4 m) above mean sea level. The flight task required holding a constant airspeed, altitude, and heading at an airspeed significantly slower than the aircraft's minimum drag speed. The simulated aircraft's inherent instability at the target speed challenged the pilot to maintain constant control of the aircraft in order to minimize deviations from the assigned flight parameters. Each pilot's flight performance was evaluated by measuring all deviations from assigned target values. Hypoxia degraded the pilot's precision of altitude and airspeed control by 53%, a statistically significant decrease in flight performance. The effect on heading control effects was not statistically significant. There was no evidence of performance differences when breathing room air pre- and post-hypoxia. Moderate levels of hypoxia degraded the ability of military instructor pilots to perform a precision slow flight task. This is one of a small number of studies to quantify an effect of hypoxia on primary flight performance.

Effects of microgravity on osteoblast growth

NASA Technical Reports Server (NTRS)

Hughes-Fulford, M.; Tjandrawinata, R.; Fitzgerald, J.; Gasuad, K.; Gilbertson, V.

1998-01-01

Studies from space flights over the past two decades have demonstrated that basic physiological changes occur in humans during space flight. These changes include cephalic fluid shifts, loss of fluid and electrolytes, loss of muscle mass, space motion sickness, anemia, reduced immune response, and loss of calcium and mineralized bone. The cause of most of these manifestations is not known and until recently, the general approach was to investigate general systemic changes, not basic cellular responses to microgravity. Recently analyzed data from the 1973-1974 Skylabs disclose that there is a rise in the systemic hormone, cortisol, which may play a role in bone loss in flight. In two flights where bone growth was measured (Skylabs 3 and 4), the crew members had a significant loss of calcium accompanied by a rise in 24 hour urinary cortisol during the entire flight period. In ground-based work on osteoblasts, we have demonstrated that equivalent amounts of glucocorticoids can inhibit osteoblast cell growth. In addition, this laboratory has recently studied gene growth and activation of mouse osteoblasts (MC3T3-E1) during spaceflight. Osteoblast cells were grown on glass coverslips, loaded in the Biorack plunger boxes 18 hours before launch and activated 19 hours after launch in the Biorack incubator under microgravity conditions. The osteoblasts were launched in a serum deprived state, activated and collected in microgravity. Samples were collected at 29 hours after sera activation (0-g, n=4; 1-g, n=4). The osteoblasts were examined for changes in gene expression and cell morphology. Approximately one day after growth activation, remarkable differences were observed in gene expression in 0-g and 1-g flight samples. The 0-g activated cells had increased c-fos mRNA when compared to flight 1-g controls. The message of immediate early growth gene, cox-2 was decreased in the microgravity activated cells when compared to ground or 1-g flight controls. Cox-1 was not detected in any of the samples. There were no significant differences in the expression of actin mRNA between the 0-g and 1-g samples. These data indicate that quiescent osteoblasts are slower to enter the cell cycle in microgravity, suggesting that the force of gravity itself may be a significant factor in bone loss in spaceflight. Preliminary data from our STS 76 flight experiment support our hypothesis that a basic biological response occurs at the tissue, cellular, and molecular level in 0-g. Here we examine ground-based and space flown data on osteoblast growth in ground-based experiments mimicking space flight conditions and in microgravity to simulate lack of gravity stress to help us understand the mechanism of bone loss by experiments.

T-34C back seat instrument panel

NASA Image and Video Library

1997-05-15

The back seat instrument panel on the NASA T-34C chase plane. In its role as a military trainer, the instructor pilot would ride in the back seat, while the student would be in the front seat. As a chase plane, the back seat would be occupied by a photographer. The aircraft was previously used at the Lewis Research Center in propulsion experiments involving turboprop engines, and was used as a chase aircraft at Dryden for smaller and slower research projects. Chase aircraft accompany research flights for photography and video purposes, and also as support for safety and research. At Dryden, the T-34 is used mainly for smaller remotely piloted vehicles which fly slower than NASA's F-18's, used for larger scale projects. This aircraft was returned to the U.S. Navy in May of 2002. The T-34C, built by Beech, carries a crew of 2 and is nicknamed the Mentor.

Changes in gene expression and signal transduction in microgravity

NASA Technical Reports Server (NTRS)

Hughes-Fulford, M.

2001-01-01

Studies from space flights over the past three decades have demonstrated that basic physiological changes occur in humans during space flight. These changes include cephalic fluid shifts, loss of fluid and electrolytes, loss of muscle mass, space motion sickness, anemia, reduced immune response, and loss of calcium and mineralized bone. The cause of most of these manifestations is not known and until recently, the general approach was to investigate general systemic changes, not basic cellular responses to microgravity. This laboratory has recently studied gene growth and activation of normal osteoblasts (MC3T3-El) during spaceflight. Osteoblast cells were grown on glass coverslips and loaded in the Biorack plunger boxes. The osteoblasts were launched in a serum deprived state, activated in microgravity and collected in microgravity. The osteoblasts were examined for changes in gene expression and signal transduction. Approximately one day after growth activation significant changes were observed in gene expression in 0-G flight samples. Immediate early growth genes/growth factors cox-2, c-myc, bcl2, TGF beta1, bFGF and PCNA showed a significant diminished mRNA induction in microgravity FCS activated cells when compared to ground and 1-G flight controls. Cox-1 was not detected in any of the samples. There were no significant differences in the expression of reference gene mRNA between the ground, 0-G and 1-G samples. The data suggest that quiescent osteoblasts are slower to enter the cell cycle in microgravity and that the lack of gravity itself may be a significant factor in bone loss in spaceflight. Preliminary data from our STS 76 flight experiment support our hypothesis that a basic biological response occurs at the tissue, cellular, and molecular level in 0-G. Here we examine ground-based and space flown data to help us understand the mechanism of bone loss in microgravity.

Microgravity Effects on Plant Growth and Lignification

NASA Astrophysics Data System (ADS)

Cowles, Joe R.; Lemay, Richard; Jahns, Gary

1988-12-01

Lignin is a major cellular component of higher plants. One function of lignin is to support vertical plant growth in a gravity environment. Various investigators working in the 1 g environment have concluded that lignification is influenced by gravity. An experiment was designed for flight on Spacelab II to determine the effect of microgravity on lignification in young plant seedlings. A secondary objective of the experiment was to examine the effect of microgravity on overall seedling growth. Mung bean and oat seeds germinated and the seedlings grew during the Spacelab II mission. Growth of flight mung bean and oat seedlings, however, was slower, and the seedlings exhibited stem and root orientation difficulties. Flight pine seedlings were similar in appearance and growth to 1 g controls. The rate of lignin formation in seedlings grown in space was significantly less in all three species in comparison to 1 g controls. The experiment provided direct evidence that lignification is slowed in a microgravity environment.

A High-Throughput Processor for Flight Control Research Using Small UAVs

NASA Technical Reports Server (NTRS)

Klenke, Robert H.; Sleeman, W. C., IV; Motter, Mark A.

2006-01-01

There are numerous autopilot systems that are commercially available for small (<100 lbs) UAVs. However, they all share several key disadvantages for conducting aerodynamic research, chief amongst which is the fact that most utilize older, slower, 8- or 16-bit microcontroller technologies. This paper describes the development and testing of a flight control system (FCS) for small UAV s based on a modern, high throughput, embedded processor. In addition, this FCS platform contains user-configurable hardware resources in the form of a Field Programmable Gate Array (FPGA) that can be used to implement custom, application-specific hardware. This hardware can be used to off-load routine tasks such as sensor data collection, from the FCS processor thereby further increasing the computational throughput of the system.

FAA Long-Range Aviation Forecasts Fiscal Years 2005-2020

DTIC Science & Technology

1993-09-01

assumptions translate into somewhat slower growth of aviation activity and FAA workload measures during the extended 16 -year period (2004 to 2020) than was...OPERATIONS 1.8 1.2 INSTRUMENT OPERATIONS 2.0 1.3 IFR AIRCRAFT HANDLED 2.0 1.3 FLIGHT SERVICE STTIONS (0.2) 0.1 2 II. LONG-RANGE FORECAST ASSUMPTIONS The...product (GDP), adjusted for price changes and expressed in 1987 dollars, will average 1.9 percent annually over the extended 16 -year fore- cast period

ARC-2012-ACD12-0020-002

NASA Image and Video Library

2012-02-02

Shen_Nargis: Snapshot of a very large simulation showing the altitude and velocity of wind speeds within the 2008 Cyclone Nargis. Top wind speeds for the storm were measured at 135 mph. The lowest altitude winds are shown in blue, while the highest altitude winds are shown in pink. Wind speed is shown by color density: higher density denotes stronger winds, slightly transparent color indicates slower wind speeds. Credit: Bryan Green, NASA Ames Research Center; Bo-wen Shen, NASA Goddard Space Flight Center.

Neutron spectroscopy for pulsed beams with frame overlap using a double time-of-flight technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrig, K. P.; Goldblum, B. L.; Brown, J. A.

A new double time-of- ight (dTOF) neutron spectroscopy technique has been developed for pulsed broad spectrum sources with a duty cycle that results in frame overlap, where fast neutrons from a given pulse overtake slower neutrons from previous pulses. Using a tunable beam at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory, neutrons were produced via thick-target breakup of 16 MeV deuterons on a beryllium target in the cyclotron vault. The breakup spectral shape was deduced from a dTOF measurement using an array of EJ-309 organic liquid scintillators. Simulation of the neutron detection efficiency of the scintillator array was performedmore » using both GEANT4 and MCNP6. The efficiency- corrected spectral shape was normalized using a foil activation technique to obtain the energy-dependent flux of the neutron beam at zero degrees with respect to the incoming deuteron beam. The dTOF neutron spectrum was compared to spectra obtained using HEPROW and GRAVEL pulse height spectrum unfolding techniques. While the unfolding and dTOF results exhibit some discrepancies in shape, the integrated flux values agree within two standard deviations. As a result, this method obviates neutron time-of-flight spectroscopy challenges posed by pulsed beams« less

Neutron spectroscopy for pulsed beams with frame overlap using a double time-of-flight technique

DOE PAGES

Harrig, K. P.; Goldblum, B. L.; Brown, J. A.; ...

2017-10-16

A new double time-of- ight (dTOF) neutron spectroscopy technique has been developed for pulsed broad spectrum sources with a duty cycle that results in frame overlap, where fast neutrons from a given pulse overtake slower neutrons from previous pulses. Using a tunable beam at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory, neutrons were produced via thick-target breakup of 16 MeV deuterons on a beryllium target in the cyclotron vault. The breakup spectral shape was deduced from a dTOF measurement using an array of EJ-309 organic liquid scintillators. Simulation of the neutron detection efficiency of the scintillator array was performedmore » using both GEANT4 and MCNP6. The efficiency- corrected spectral shape was normalized using a foil activation technique to obtain the energy-dependent flux of the neutron beam at zero degrees with respect to the incoming deuteron beam. The dTOF neutron spectrum was compared to spectra obtained using HEPROW and GRAVEL pulse height spectrum unfolding techniques. While the unfolding and dTOF results exhibit some discrepancies in shape, the integrated flux values agree within two standard deviations. As a result, this method obviates neutron time-of-flight spectroscopy challenges posed by pulsed beams« less

European corn borer sex pheromone : Inhibition and elicitation of behavioral response by analogs.

PubMed

Schwarz, M; Klun, J A; Uebel, E C

1990-05-01

The male sexual behavior-stimulating and inhibiting properties of a series of analogs of the European corn borer sex pheromone were determined in a flight tunnel. The structural requirements for inhibition of pheromonal response were far less restrictive than those for elicitation of that response. Analogs that by themselves elicited upwind flight response from males at a low dose were generally less inhibitory to male response than many of the analogs that had no pheromonal activity. These findings suggest that many pheromone analogs bind to pheromone receptors without provoking behavioral response and possibly undergo slower degradation on the antenna than pheromonally active compounds. The disparity of response to analogs by two pheromonal types of the European corn borer indicates that the pheromone receptor and pheromone catabolic systems are biochemically very different in the two types.

The effect of altered gravity on immune cells (Ground studies: TRIPLE LUX-A BIOLAB experiment)

NASA Astrophysics Data System (ADS)

Horn, Astrid; Huber, Kathrin; Kuebler, Ulrich; Briganti, Luca; Baerwalde, Sven; Zander, Vanja; Ullrich, Oliver; Hemmersbach, Ruth

The experiment TRIPLE LUX A, whose performance on Biolab is foreseen for 2010, aims to increase the information about the functioning of immune cells during space flight. Thus, we investigate the impact of altered gravity -microgravity and hypergravity conditions -on the immune response of mammalian macrophages. Previous studies had already demonstrated that phagocytosis in macrophages, an essential step in the innate immune response, is decreased on a fast rotating clinostat. Now, the production of ROS (reactive oxygen species) within the oxidative burst reaction, was measured by means of a luminol assay (luminescence + photo-multiplier technique) comparable to the set up which will be used in the TRIPLE LUX flight hardware. The kinetics of the ROS production was investigated a) under 1 g conditions, b) on a clinostat (with one rotation axis) under varied rotational speed c) in short-term real micro-gravity on a parabolic flight and d) in hypergravity (1.8 g) on the Short Arm Human Centrifuge (SAHC) at DLR Cologne. By means of a photomultiplier clinostat online kinetic luminescent measurements during clinorotation were possible. Permanent fast clinorotation (60 rpm) leads to a dramatic reduction of the oxidative burst signal by up to 60% compared to the signal at 1 g. Slower rotation (30 rpm to 2 rpm) reduces the signal strength even more by up to 90% of the original strength. 60 rpm clinorotation as well as short-term real microgravity (22 s) during parabolic flight likewise decreases the signal of the oxidative burst to a comparable amount, thus the term "simulated weightlessness" is valid for the chosen experimental condi-tion. In contrast, hypergravity leads to a significant signal increase. The results demonstrate a clear effect of altered gravity on the immune response of the macrophages. In the upcoming ISS experiment the established test system (oxidative burst of macrophages) will be tested in continues microgravity within the Biolab hardware, designed by EADS Astrium. The core of the TRIPLELUX experiment hardware onboard the International Space Station consists of two specifically developed Biolab Advanced Experiment Containers (AECs) that, exploiting Biolab automatic features such as the robotic arm Handling Mechanism, allow for fully-automated life support of sample cells as well as investigations of their behaviour in microgravity through the measurement of luminescence.

Task-dependent activation of distinct fast and slow(er) motor pathways during motor imagery.

PubMed

Keller, Martin; Taube, Wolfgang; Lauber, Benedikt

2018-02-22

Motor imagery and actual movements share overlapping activation of brain areas but little is known about task-specific activation of distinct motor pathways during mental simulation of movements. For real contractions, it was demonstrated that the slow(er) motor pathways are activated differently in ballistic compared to tonic contractions but it is unknown if this also holds true for imagined contractions. The aim of the present study was to assess the activity of fast and slow(er) motor pathways during mentally simulated movements of ballistic and tonic contractions. H-reflexes were conditioned with transcranial magnetic stimulation at different interstimulus intervals to assess the excitability of fast and slow(er) motor pathways during a) the execution of tonic and ballistic contractions, b) motor imagery of these contraction types, and c) at rest. In contrast to the fast motor pathways, the slow(er) pathways displayed a task-specific activation: for imagined ballistic as well as real ballistic contractions, the activation was reduced compared to rest whereas enhanced activation was found for imagined tonic and real tonic contractions. This study provides evidence that the excitability of fast and slow(er) motor pathways during motor imagery resembles the activation pattern observed during real contractions. The findings indicate that motor imagery results in task- and pathway-specific subliminal activation of distinct subsets of neurons in the primary motor cortex. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Insights into Submicron Aerosol Composition and Sources from the WINTER Aircraft Campaign Over the Eastern US.

NASA Astrophysics Data System (ADS)

Schroder, J. C.; Campuzano Jost, P.; Day, D. A.; Fibiger, D. L.; McDuffie, E. E.; Blake, N. J.; Hills, A. J.; Hornbrook, R. S.; Apel, E. C.; Weinheimer, A. J.; Campos, T. L.; Brown, S. S.; Jimenez, J. L.

2015-12-01

The WINTER aircraft campaign was a recent field experiment to probe the sources and evolution of gas pollutants and aerosols in Northeast US urban and industrial plumes during the winter. A highly customized Aerodyne aerosol mass spectrometer (AMS) was flown on the NCAR C-130 to characterize submicron aerosol composition and evolution. Thirteen research flights were conducted covering a wide range of conditions, including rural, urban, and marine environments during day and night. Organic aerosol (OA) was a large component of the submicron aerosol in the boundary layer. The fraction of OA (fOA) was smaller (35-40%) than in recent US summer campaigns (~60-70%). Biomass burning was observed to be an important source of OA in the boundary layer, which is consistent with recent wintertime studies that show a substantial contribution of residential wood burning to the OA loadings. OA oxygenation (O/C ratio) shows a broad distribution with a substantial fraction of smaller O/C ratios when compared to previous summertime campaigns. Since measurements were rarely made very close to primary sources (i.e. directly above urban areas), this is consistent with oxidative chemistry being slower during winter. SOA formation and aging in the NYC plume was observed during several flights and compared with summertime results from LA (CalNex) and Mexico City (MILAGRO). Additionally, an oxidation flow reactor (OFR) capable of oxidizing ambient air up to several equivalent days of oxidation was deployed for the first time in an aircraft platform. The aerosol outflow of the OFR was sampled with the AMS to provide real-time snapshots of the potential for aerosol formation and aging. For example, a case study of a flight through the Ohio River valley showed evidence of oxidation of SO2 to sulfate. The measured sulfate enhancements were in good agreement with our OFR chemical model. OFR results for SOA will be discussed.

Eye-Head Coordination in 31 Space Shuttle Astronauts during Visual Target Acquisition.

PubMed

Reschke, Millard F; Kolev, Ognyan I; Clément, Gilles

2017-10-27

Between 1989 and 1995, NASA evaluated how increases in flight duration of up to 17 days affected the health and performance of Space Shuttle astronauts. Thirty-one Space Shuttle pilots participating in 17 space missions were tested at 3 different times before flight and 3 different times after flight, starting within a few hours of return to Earth. The astronauts moved their head and eyes as quickly as possible from the central fixation point to a specified target located 20°, 30°, or 60° off center. Eye movements were measured with electro-oculography (EOG). Head movements were measured with a triaxial rate sensor system mounted on a headband. The mean time to visually acquire the targets immediately after landing was 7-10% (30-34 ms) slower than mean preflight values, but results returned to baseline after 48 hours. This increase in gaze latency was due to a decrease in velocity and amplitude of both the eye saccade and head movement toward the target. Results were similar after all space missions, regardless of length.

Blind Seer: A Scalable Private DBMS

DTIC Science & Technology

2014-05-01

searchable index terms per DB row, in time comparable to (insecure) MySQL (many practical queries can be privately executed with work 1.2-3 times slower...than MySQL , although some queries are costlier). We support a rich query set, including searching on arbitrary boolean formulas on keywords and ranges...index terms per DB row, in time comparable to (insecure) MySQL (many practical queries can be privately executed with work 1.2-3 times slower than MySQL

Angular distribution, kinetic energy distributions, and excitation functions of fast metastable oxygen fragments following electron impact of CO2

NASA Technical Reports Server (NTRS)

Misakian, M.; Mumma, M. J.; Faris, J. F.

1975-01-01

Dissociative excitation of CO2 by electron impact was studied using the methods of translational spectroscopy and angular distribution analysis. Earlier time of flight studies revealed two overlapping spectra, the slower of which was attributed to metastable CO(a3 pi) fragments. The fast peak is the focus of this study. Threshold energy, angular distribution, and improve time of flight measurements indicate that the fast peak actually consists of five overlapping features. The slowest of the five features is found to consist of metastable 0(5S) produced by predissociation of a sigma u + state of CO2 into 0(5S) + CO(a3 pi). Oxygen Rydberg fragments originating directly from a different sigma u + state are believed to make up the next fastest feature. Mechanisms for producing the three remaining features are discussed.

Flight evaluation of the transonic stability and control characteristics of an airplane incorporating a supercritical wing

NASA Technical Reports Server (NTRS)

Matheny, N. W.; Gatlin, D. H.

1978-01-01

A TF-8A airplane was equipped with a transport type supercritical wing and fuselage fairings to evaluate predicted performance improvements for cruise at transonic speeds. A comparison of aerodynamic derivatives extracted from flight and wind tunnel data showed that static longitudinal stability, effective dihedral, and aileron effectiveness, were higher than predicted. The static directional stability derivative was slower than predicted. The airplane's handling qualities were acceptable with the stability augmentation system on. The unaugmented airplane exhibited some adverse lateral directional characteristics that involved low Dutch roll damping and low roll control power at high angles of attack and roll control power that was greater than satisfactory for transport aircraft at cruise conditions. Longitudinally, the aircraft exhibited a mild pitchup tendency. Leading edge vortex generators delayed the onset of flow separation, moving the pitchup point to a higher lift coefficient and reducing its severity.

Designing and building a permanent magnet Zeeman slower for calcium atoms using a 3D printer

NASA Astrophysics Data System (ADS)

Parsagian, Alexandria; Kleinert, Michaela

2015-10-01

We present the design of a Zeeman slower for calcium atoms using permanent magnets instead of more traditional electromagnets and the novel technique of 3D printing to create a very robust and flexible structure for these magnets. Zeeman slowers are ideal tools to slow atoms from several hundreds of meters per second to just a few tens of meters per second. These slower atoms can then easily be trapped in a magneto-optical trap, making Zeeman slowers a very valuable tool in many cold atom labs. The use of permanent magnets and 3D printing results in a highly stable and robust slower that is suitable for undergraduate laboratories. In our design, we arranged 28 magnet pairs, 2.0 cm apart along the axis of the slower and at varying radial distances from the axis. We determined the radial position of the magnets by simulating the combined field of all magnet pairs using Mathematica and comparing it to the ideal theoretical field for a Zeeman slower. Finally, we designed a stable, robust, compact, and easy-to-align mounting structure for the magnets in Google Sketchup, which we then printed using a commercially available 3D printer by Solidoodle. The resulting magnetic field is well suited to slow calcium atoms from the 770 m/s rms velocity at a temperature of 950 K, down to the capture velocity of the magneto-optical trap.

Differential Kinetics of Aspergillus nidulans and Aspergillus fumigatus Phagocytosis.

PubMed

Gresnigt, Mark S; Becker, Katharina L; Leenders, Floris; Alonso, M Fernanda; Wang, Xiaowen; Meis, Jacques F; Bain, Judith M; Erwig, Lars P; van de Veerdonk, Frank L

2018-01-01

Invasive aspergillosis mainly occurs in immunocompromised patients and is commonly caused by Aspergillus fumigatus, while A.nidulans is rarely the causative agent. However, in chronic granulomatous disease (CGD) patients, A. nidulans is a frequent cause of invasive aspergillosis and is associated with higher mortality. Immune recognition of A. nidulans was compared to A. fumigatus to offer an insight into why A. nidulans infections are prevalent in CGD. Live cell imaging with J774A.1 macrophage-like cells and LC3-GFP-mCherry bone marrow-derived macrophages (BMDMs) revealed that phagocytosis of A. nidulans was slower compared to A. fumigatus. This difference could be attributed to slower migration of J774A.1 cells and a lower percentage of migrating BMDMs. In addition, delayed phagosome acidification and LC3-associated phagocytosis was observed with A. nidulans. Cytokine and oxidative burst measurements in human peripheral blood mononuclear cells revealed a lower oxidative burst upon challenge with A. nidulans. In contrast, A. nidulans induced significantly higher concentrations of cytokines. Collectively, our data demonstrate that A. nidulans is phagocytosed and processed at a slower rate compared to A. fumigatus, resulting in reduced fungal killing and increased germination of conidia. This slower rate of A. nidulans clearance may be permissive for overgrowth within certain immune settings. The Author(s). Published by S. Karger AG, Basel.

'No cost of echolocation for flying bats' revisited.

PubMed

Voigt, Christian C; Lewanzik, Daniel

2012-08-01

Echolocation is energetically costly for resting bats, but previous experiments suggested echolocation to come at no costs for flying bats. Yet, previous studies did not investigate the relationship between echolocation, flight speed, aerial manoeuvres and metabolism. We re-evaluated the 'no-cost' hypothesis, by quantifying the echolocation pulse rate, the number of aerial manoeuvres (landings and U-turns), and the costs of transport in the 5-g insectivorous bat Rhogeessa io (Vespertilionidae). On average, bats (n = 15) travelled at 1.76 ± 0.36 m s⁻¹ and performed 11.2 ± 6.1 U-turns and 2.8 ± 2.9 ground landings when flying in an octagonal flight cage. Bats made more U-turns with decreasing wing loading (body weight divided by wing area). At flight, bats emitted 19.7 ± 2.7 echolocation pulses s⁻¹ (range 15.3-25.8 pulses s⁻¹), and metabolic rate averaged 2.84 ± 0.95 ml CO₂ min⁻¹, which was more than 16 times higher than at rest. Bats did not echolocate while not engaged in flight. Costs of transport were not related to the rate of echolocation pulse emission or the number of U-turns, but increased with increasing number of landings; probably as a consequence of slower travel speed when staying briefly on ground. Metabolic power of flight was lower than predicted for R. io under the assumption that energetic costs of echolocation call production is additive to the aerodynamic costs of flight. Results of our experiment are consistent with the notion that echolocation does not add large energetic costs to the aerodynamic power requirements of flight in bats.

Nectar vs. pollen loading affects the tradeoff between flight stability and maneuverability in bumblebees

PubMed Central

Mountcastle, Andrew M.; Combes, Stacey A.

2015-01-01

Bumblebee foragers spend a significant portion of their lives transporting nectar and pollen, often carrying loads equivalent to more than half their body mass. Whereas nectar is stored in the abdomen near the bee’s center of mass, pollen is carried on the hind legs, farther from the center of mass. We examine how load position changes the rotational moment of inertia in bumblebees and whether this affects their flight maneuverability and/or stability. We applied simulated pollen or nectar loads of equal mass to Bombus impatiens bumblebees and examined flight performance in a wind tunnel under three conditions: flight in unsteady flow, tracking an oscillating flower in smooth flow, and flower tracking in unsteady flow. Using an inertial model, we estimated that carrying a load on the legs rather than in the abdomen increases a bee’s moment of inertia about the roll and yaw axes but not the pitch axis. Consistent with these predictions, we found that bees carrying a load on their legs displayed slower rotations about their roll and yaw axes, regardless of whether these rotations were driven by external perturbations or self-initiated steering maneuvers. This allowed pollen-loaded bees to maintain a more stable body orientation and higher median flight speed in unsteady flow but reduced their performance when tracking a moving flower, supporting the concept of a tradeoff between stability and maneuverability. These results demonstrate that the types of resources collected by bees affect their flight performance and energetics and suggest that wind conditions may influence resource selection. PMID:26240364

Testing the time-of-flight model for flagellar length sensing.

PubMed

Ishikawa, Hiroaki; Marshall, Wallace F

2017-11-07

Cilia and flagella are microtubule-based organelles that protrude from the surface of most cells, are important to the sensing of extracellular signals, and make a driving force for fluid flow. Maintenance of flagellar length requires an active transport process known as intraflagellar transport (IFT). Recent studies reveal that the amount of IFT injection negatively correlates with the length of flagella. These observations suggest that a length-dependent feedback regulates IFT. However, it is unknown how cells recognize the length of flagella and control IFT. Several theoretical models try to explain this feedback system. We focused on one of the models, the "time-of-flight" model, which measures the length of flagella on the basis of the travel time of IFT protein in the flagellar compartment. We tested the time-of-flight model using Chlamydomonas dynein mutant cells, which show slower retrograde transport speed. The amount of IFT injection in dynein mutant cells was higher than that in control cells. This observation does not support the prediction of the time-of-flight model and suggests that Chlamydomonas uses another length-control feedback system rather than that described by the time-of-flight model. © 2017 Ishikawa and Marshall. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Testing of models of VVH particle sources and propagation

NASA Technical Reports Server (NTRS)

Blanford, G. E., Jr.; Friedlander, M. W.; Hoppe, M.; Klarmann, J.; Walker, R. M.; Wefel, J. P.

1974-01-01

For comparisons between theoretical and observed charge spectra of VVH particles to be meaningful, at least two conditions must be met. First, charge resolution must be adequate to separate important groups of nuclei, and there should be no significant systematic errors in the charge scale developed. Second, there must be adequate rejection of slower particles of smaller Z, which have been observed in several flights. Within these conditions, it has been shown that observed features of the charge spectrum are not accidents of the analysis but reflect real variations in the relative abundances that must be explained by any successful model.

Preliminary study of the use of the STAR-100 computer for transonic flow calculations

NASA Technical Reports Server (NTRS)

Keller, J. D.; Jameson, A.

1977-01-01

An explicit method for solving the transonic small-disturbance potential equation is presented. This algorithm, which is suitable for the new vector-processor computers such as the CDC STAR-100, is compared to successive line over-relaxation (SLOR) on a simple test problem. The convergence rate of the explicit scheme is slower than that of SLOR, however, the efficiency of the explicit scheme on the STAR-100 computer is sufficient to overcome the slower convergence rate and allow an overall speedup compared to SLOR on the CYBER 175 computer.

Protein crystal growth results from shuttle flight 51-F

NASA Technical Reports Server (NTRS)

Bugg, C. E.

1985-01-01

The protein crystal growth (PCG) experiments run on 51-F were analyzed. It was found that: (1) sample stability is increased over that observed during the experiments on flight 51-D; (2) the dialysis experiments produced lysozyme crystals that were significantly larger than those obtained in our identical ground-based studies; (3) temperature fluctuations apparently caused problems during the crystallization experiments on 51-F; (4) it is indicated that teflon tape stabilizes droplets on the syringe tips; (5) samples survived during the reentry and landing in glass tips that were not stoppered with plungers; (6) from the ground-based studies, it was expected that equilibration should be complete within 2 to 4 days for all of these vapor-diffusion experiments, thus it appears that the vapor diffusion rates are somewhat slower under microgravity conditions; (7) drop tethering was highly successful, all four of the tethered drops were stable, even though they contained MPD solutions; (8) the PCG experiments on 51-F were done to assess the hardware and experimental procedures that are developed for future flights, when temperature control will be available. Lysozyme crystals obtained by microdialysis are considerably larger than those obtained on the ground, using the identical apparatus and procedures.

Going Up. A GPS Receiver Adapts to Space

NASA Technical Reports Server (NTRS)

Lightsey, E. Glenn; Simpson, James E.

2000-01-01

Current plans for the space station call for the GPS receiver to be installed on the U.S. lab module of the station in early 2001 (ISS Assembly Flight SA), followed by the attachment of the antenna array in late 2001 (Flight 8A). At that point the U.S. ISS guidance and control system will be operational. The flight of SIGI on the space station represents a "coming of age" for GPS technology on spacecraft. For at least a decade, the promise of using GPS receivers to automate spacecraft operations, simplify satellite design, and reduce mission costs has enticed satellite designers. Integration of this technology onto spacecraft has been slower than some originally anticipated. However, given the complexity of the GPS sensor, and the importance of the functions it performs, its incorporation into mainstream satellite design has probably occurred at a very reasonable pace. Going from providing experimental payloads on small, unmanned satellites to performing critical operational functions on manned vehicles has been a major evolution. If all goes as planned in the next few months, GPS receivers will soon provide those critical functions on one of the most complex spacecraft in history, the International Space Station.

Difficulty with Out-Loud and Silent Reading in Glaucoma

PubMed Central

Ramulu, Pradeep Y.; Swenor, Bonnielin K.; Jefferys, Joan L.; Friedman, David S.; Rubin, Gary S.

2013-01-01

Purpose. We evaluated the impact of glaucoma on out-loud and silent reading. Methods. Glaucoma patients with bilateral visual field (VF) loss and normally-sighted controls had the following parameters measured: speed reading an International Reading Speed Text (IReST) passage out loud, maximum out-loud MNRead chart reading speed, sustained (30 minutes) silent reading speed, and change in reading speed during sustained silent reading. Results. Glaucoma subjects read slower than controls on the IReST (147 vs. 163 words per minute [wpm], P < 0.001), MNRead (172 vs. 186 wpm, P < 0.001), and sustained silent (179 vs. 218 wpm, P < 0.001) tests. In multivariable analyses adjusting for age, race, sex, education, employment, and cognition, IReST and MNRead reading speeds were 12 wpm (6%–7%) slower among glaucoma subjects compared to controls (P < 0.01 for both), while sustained silent reading speed was 16% slower (95% confidence interval [CI] = −24 to −6%, P = 0.002). Each 5 decibel (dB) decrement in better-eye VF mean deviation was associated with 6 wpm slower IReST reading (95% CI = −9 to −3%, P < 0.001), 5 wpm slower MNRead reading (95% CI = −7 to −2%, P < 0.001), and 9% slower sustained silent reading (95% CI = −13 to −6%, P < 0.001). A reading speed decline of 0.5 wpm/min or more over the sustained silent reading period was more common among glaucoma subjects than controls (odds ratio [OR] = 2.2, 95% CI = 1.0–4.9, P < 0.05). Conclusions. Reading speed is slower among glaucoma patients with bilateral VF loss, with the greatest impact present during sustained silent reading. Persons with glaucoma fatigue during silent reading, resulting in slower reading over time. PMID:23074207

Functional Sensory-Motor Performance Following Long Term Space Flight: The First Results of "Field Test" Experiment

NASA Technical Reports Server (NTRS)

Tomilovskaya, E. S.; Rukavishnikov, I. V.; Kofman, I. S.; Kitov, V. V.; Grishin, A. P.; Yu, N.; Lysova.; Cerisano, J. M.; Kozlovskaya, I. B.; Reschke, M. F.

2014-01-01

The effect that extended-duration space flights may have on human space travelers, including exploration missions, is widely discussed at the present time. Specifically, there is an increasing amount of evidence showing that the physical capacity of cosmonauts is significantly reduced after long-duration space flights. It is evident that the most impaired functions are those that rely on gravity, particularly up right posture and gait. Because of the sensorimotor disturbances manifested in the neurology of the posture and gait space flight and postflight changes may also be observed in debilitating motion sickness. While the severity of particular symptoms varies, disturbances in spatial orientation and alterations in the accuracy of voluntary movements are persistently observed after long-duration space flights. At this time most of the currently available data are primarily descriptive and not yet suitable for predicting operational impacts of most sensorimotor decrements observed upon landing on planetary surfaces or asteroids. In particular there are no existing data on the recovery dynamics or functionality of neurological, cardiovascular or muscle performance making it difficult to model or simulate the cosmonauts' activity after landing and develop the appropriate countermeasure that will ensure the rapid and safe recovery of crewmembers immediately after landing in what could be hostile environments. However and as a starting position, the videos we have acquired during recent data collection following the long duration flights of cosmonauts and astronauts walking and performing other tasks shortly after return from space flight speak volumes about their level of deconditioning. A joint Russian-American team has developed a new study specifically to address the changes in crewmembers performance and the recovery of performance with the intent of filling the missing data gaps. The first (pilot) phase of this study includes recording body kinematics and quantifying the coordination and timing of relatively simple basic movements - transition from seated and prone positions to standing, walking, stepping over obstacles, tandem walking, muscle compliance, as well as characteristics of postural sway and orthostatic tolerance. Testing for changes in these parameters have been initiated in the medical tent at the landing site. The first set of experiments showed that during the first hour after landing, cosmonauts and astronauts were able to execute (although slower and with more effort than preflight) simple movements such as egress from a seated or prone position and also to remain standing for 3.5 minutes without exhibiting pronounced cardiovascular changes. More challenging tests, however, demonstrated a prominent reduction in coordination - the obstacle task, for example, was performed at much slower speed and with a marked overestimation of the obstacle height and tandem walking was greatly degraded suggesting significant changes in proprioception, brainstem and vestibular function. There is some speculation that the neural changes, either from the bottom-up or top down may be long lasting; requiring compensatory responses that will modify or mask the adverse responses we have observed. Furthermore, these compensatory responses may actually be beneficial, helping achieve a more rapid adaptation to both weightlessness and a return to earth.

Flight investigation of the effect of tail configuration on stall, spin, and recovery characteristics of a low-wing general aviation research airplane

NASA Technical Reports Server (NTRS)

Stough, H. Paul, III; Patton, James M., Jr.; Sliwa, Steven M.

1987-01-01

Flight tests were performed to investigate the stall, spin, and recovery characteristics of a low-wing, single-engine, light airplane with four interchangeable tail configurations. The four tail configurations were evaluated for effects of varying mass distribution, center-of-gravity position, and control inputs. The airplane tended to roll-off at the stall. Variations in tail configuration produced spins ranging from 40 deg to 60 deg angle of attack and turn rates of about 145 to 208 deg/sec. Some unrecoverable flat spins were encountered which required use of the airplane spin chute for recovery. For recoverable spins, antispin rudder followed by forward wheel with ailerons centered provided the quickest spin recovery. The moderate spin modes agreed very well with those predicted from spin-tunnel model tests, however, the flat spin was at a lower angle of attack and a slower rotation rate than indicated by the model tests.

Kinematics of flap-bounding flight in the zebra finch over a wide range of speeds

PubMed

Tobalske; Peacock; Dial

1999-07-01

It has been proposed elsewhere that flap-bounding, an intermittent flight style consisting of flapping phases interspersed with flexed-wing bounds, should offer no savings in average mechanical power relative to continuous flapping unless a bird flies 1.2 times faster than its maximum range speed (Vmr). Why do some species use intermittent bounds at speeds slower than 1.2Vmr? The 'fixed-gear hypothesis' suggests that flap-bounding is used to vary mean power output in small birds that are otherwise constrained by muscle physiology and wing anatomy to use a fixed muscle shortening velocity and pattern of wing motion at all flight speeds; the 'body-lift hypothesis' suggests that some weight support during bounds could make flap-bounding flight aerodynamically advantageous in comparison with continuous flapping over most forward flight speeds. To test these predictions, we studied high-speed film recordings (300 Hz) of wing and body motion in zebra finches (Taenopygia guttata, mean mass 13.2 g, N=4) taken as the birds flew in a variable-speed wind tunnel (0-14 m s-1). The zebra finches used flap-bounding flight at all speeds, so their flight style was unique compared with that of birds that facultatively shift from continuous flapping or flap-gliding at slow speeds to flap-bounding at fast speeds. There was a significant effect of flight speed on all measured aspects of wing motion except percentage of the wingbeat spent in downstroke. Changes in angular velocity of the wing indicated that contractile velocity in the pectoralis muscle changed with flight speed, which is not consistent with the fixed-gear hypothesis. Although variation in stroke-plane angle relative to the body, pronation angle of the wing and wing span at mid-upstroke showed that the zebra finch changed within-wingbeat geometries according to speed, a vortex-ring gait with a feathered upstroke appeared to be the only gait used during flapping. In contrast, two small species that use continuous flapping during slow flight (0-4 m s-1) either change wingbeat gait according to flight speed or exhibit more variation in stroke-plane and pronation angles relative to the body. Differences in kinematics among species appear to be related to wing design (aspect ratio, skeletal proportions) rather than to pectoralis muscle fiber composition, indicating that the fixed-gear hypothesis should perhaps be modified to exclude muscle physiology and to emphasize constraints due to wing anatomy. Body lift was produced during bounds at speeds from 4 to 14 m s-1. Maximum body lift was 0.0206 N (15.9 % of body weight) at 10 m s-1; body lift:drag ratio declined with increasing air speed. The aerodynamic function of bounds differed with increasing speed from an emphasis on lift production (4-10 m s-1) to an emphasis on drag reduction with a slight loss in lift (12 and 14 m s-1). From a mathematical model of aerodynamic costs, it appeared that flap-bounding offered the zebra finch an aerodynamic advantage relative to continuous flapping at moderate and fast flight speeds (6-14 m s-1), with body lift augmenting any savings offered solely by flap-bounding at speeds faster than 7.1 m s-1. The percentage of time spent flapping during an intermittent flight cycle decreased with increasing speed, so the mechanical cost of transport was likely to be lowest at faster flight speeds (10-14 m s-1).

Socioeconomic Status, Race/Ethnicity, and Diurnal Cortisol Trajectories in Middle-Aged and Older Adults.

PubMed

Samuel, Laura J; Roth, David L; Schwartz, Brian S; Thorpe, Roland J; Glass, Thomas A

2018-03-02

Slow afternoon cortisol decline may be a marker of aging. We hypothesize that lower socioeconomic status (SES) and African American race are associated with lower waking cortisol and slower afternoon decline. Six salivary cortisol samples, collected within a 24-hr period from 566 cohort participants aged 56-78 years, were examined in random-effects models. SES measures included socioeconomic vulnerability (household income and assets <500% of poverty) and education (≥college, some college, and ≤high school). African Americans were compared with all others. Adjusting for age and sex, intermediate, but not low, education was associated with approximately 17% lower average waking cortisol and 1% slower decline, compared with high education. Socioeconomic vulnerability was not associated with waking cortisol or linear decline. Accounting for African American race/ethnicity, socioeconomic vulnerability was associated with a 3% faster decline, and education was not associated with cortisol. African Americans had 26% lower average waking cortisol and 1% slower decline than others. African American race/ethnicity, but not lower SES, was associated with lower waking cortisol and slower afternoon decline in middle-aged and older adults. This pattern is likely a marker of earlier biological aging in vulnerable groups. Race/ethnicity may compete with SES as a measure of cumulative vulnerability.

Gait Parameter Adjustments for Walking on a Treadmill at Preferred, Slower, and Faster Speeds in Older Adults with Down Syndrome

PubMed Central

Smith, Beth A.; Kubo, Masayoshi; Ulrich, Beverly D.

2012-01-01

The combined effects of ligamentous laxity, hypotonia, and decrements associated with aging lead to stability-enhancing foot placement adaptations during routine overground walking at a younger age in adults with Down syndrome (DS) compared to their peers with typical development (TD). Our purpose here was to examine real-time adaptations in older adults with DS by testing their responses to walking on a treadmill at their preferred speed and at speeds slower and faster than preferred. We found that older adults with DS were able to adapt their gait to slower and faster than preferred treadmill speeds; however, they maintained their stability-enhancing foot placements at all speeds compared to their peers with TD. All adults adapted their gait patterns similarly in response to faster and slower than preferred treadmill-walking speeds. They increased stride frequency and stride length, maintained step width, and decreased percent stance as treadmill speed increased. Older adults with DS, however, adjusted their stride frequencies significantly less than their peers with TD. Our results show that older adults with DS have the capacity to adapt their gait parameters in response to different walking speeds while also supporting the need for intervention to increase gait stability. PMID:22693497

High heating rate decomposition dynamics of copper oxide by nanocalorimetry-coupled time-of-flight mass spectrometry

NASA Astrophysics Data System (ADS)

Yi, Feng; DeLisio, Jeffery B.; Nguyen, Nam; Zachariah, Michael R.; LaVan, David A.

2017-12-01

The thermodynamics and evolved gases were measured during the rapid decomposition of copper oxide (CuO) thin film at rates exceeding 100,000 K/s. CuO decomposes to release oxygen when heated and serves as an oxidizer in reactive composites and chemical looping combustion. Other instruments have shown either one or two decomposition steps during heating. We have confirmed that CuO decomposes by two steps at both slower and higher heating rates. The decomposition path influences the reaction course in reactive Al/CuO/Al composites, and full understanding is important in designing reactive mixtures and other new reactive materials.

Relation between gastric emptying rate and energy intake in children compared with adults.

PubMed Central

Maes, B D; Ghoos, Y F; Geypens, B J; Hiele, M I; Rutgeerts, P J

1995-01-01

Measurement of gastric emptying rate of solids in children is difficult because the available methods are either invasive or induce a substantial radiation burden. In this study the newly developed 13C octanoic acid breath test was used to examine the gastric emptying rate of solids and milk in healthy children and to compare gastric emptying in children and adults. Fifteen healthy children and three groups of nine healthy adults were studied, using three different test meals labelled with 50 mg of 13C octanoic acid: a low caloric pancake (150 kcal), a high caloric pancake (250 kcal), and 210 ml of milk (134 kcal). Breath samples were taken before and at regular intervals after ingestion of the test meal, and analysed by isotope ratio mass spectrometry. The gastric emptying parameters were derived from the 13CO2 excretion curves by non-linear regression analysis. No significant difference was found between children and adults in the emptying rate of the low caloric solid test meal. In children as well as in adults, increasing the energy content of the solid meal resulted in a significantly slower emptying rate. The milk test meal, however, was emptied at a faster rate in adults and at slower rate in children compared with the low caloric solid test meal. Moreover, the emptying rate of milk in children was significantly slower than in adults. In conclusion, a similar gastric emptying rate of solids but a slower emptying of full cream milk was shown in children of school age compared with adults, using the non-radioactive 13C octanoic acid breath test. PMID:7883214

Prospects for a prolonged slowdown in global warming in the early 21st century

PubMed Central

Knutson, Thomas R.; Zhang, Rong; Horowitz, Larry W.

2016-01-01

Global mean temperature over 1998 to 2015 increased at a slower rate (0.1 K decade−1) compared with the ensemble mean (forced) warming rate projected by Coupled Model Intercomparison Project 5 (CMIP5) models (0.2 K decade−1). Here we investigate the prospects for this slower rate to persist for a decade or more. The slower rate could persist if the transient climate response is overestimated by CMIP5 models by a factor of two, as suggested by recent low-end estimates. Alternatively, using CMIP5 models' warming rate, the slower rate could still persist due to strong multidecadal internal variability cooling. Combining the CMIP5 ensemble warming rate with internal variability episodes from a single climate model—having the strongest multidecadal variability among CMIP5 models—we estimate that the warming slowdown (<0.1 K decade−1 trend beginning in 1998) could persist, due to internal variability cooling, through 2020, 2025 or 2030 with probabilities 16%, 11% and 6%, respectively. PMID:27901045

Use of Minute-by-Minute Cardiovascular Measurements During Tilt Tests to Strengthen Inference on the Effect of Long-Duration Space Flight on Orthostatic Hypotension

NASA Technical Reports Server (NTRS)

Feiveson, Alan H.; Lee, Stuart M. C.; Stenger, Michael B.; Stein, Sydney P.; Platts, Steven H.

2011-01-01

Typical methodology for evaluating the effects of spaceflight on orthostatic hypotension (OH) has been survival analysis of tolerance times from 80 head-up tilt tests. However when scheduled test durations are short, there may not be enough failures to allow survival analysis to adequately estimate and compare the effects of flight phase (e.g. pre-flight, number of days post-flight), flight duration, and their interaction, as well as interactions with effects of interventions or countermeasures. The problem is exacerbated in the presence of a repeated measures design, in which subjects participate in tilt tests during various flight phases. Here we show how it is possible to dramatically improve the efficiency of statistical inference in this setting by making use of the additional information contained in minute-by-minute observations of cardiovascular parameters thought to be reflective of progression towards presyncope during tilt testing. Methods: We retrospectively examined operational tilt test (OTT; 10 -min 80 head-up tilt) data from 20 International Space Station (ISS) and 66 Shuttle astronauts 10 d before launch (L-10), on landing day (R+0) and during recovery (R+1, R+3, R+6-10) depending on the level of participation. Data from 5 ISS astronauts tested on R+0 or R+1 who used non-standard countermeasures were excluded. In addition to OTT survival time, 8 cardiovascular parameters (CP: heart rate, systolic, diastolic, and mean arterial blood pressure, pulse pressure, stroke volume, cardiac output, and total peripheral resistance) that might be predictive of progression towards presyncope were measured every minute of each OTT. Statistical analysis was predicated on a two ]stage model of causation. In the first stage, flight duration and time from landing affect the astronauts' degree of OH, which is manifested in the time trends and variation of the above CPs during OTTs. In the second stage, the behavior of these parameters directly affects OTT survival time. Actual analysis proceeded in the opposite direction. First we identified those CPs or linear combinations that best predicted OTT survival regardless of what spaceflight conditions led to OTT completion or presyncope. From these, we calculated a summary statistic (one per OTT) that best predicted survival. We then used mixed ]model regression analysis to relate changes in the summary statistic to flight phase and duration. Inference on the effects of phase, duration, and their interaction on OH follows directly from this second analysis. Results: A linear combination (W) of diastolic blood pressure (DBP) and stroke volume (SV) was found to be the best predictor of OTT survival using the complete data set of minute-by-minute observations of CPs for each OTT. Furthermore, the log-transformed standard deviation of W (Z = log SW) was found to be a strong predictor of survival in the reduced data set consisting of one observation per OTT. In other words, this measure of variability of W during an OTT was the best indicator of whether or not the subject could complete the 10-min test, with higher variability (i.e. higher values of Z) being associated with greater probability of failure. In the mixed-model regression analysis where Z was now treated as a outcome with flight phase and duration groups (ISS and STS) as predictors, we found that there was a significantly more variability in W (higher values of Z) for both groups at R+0, but with no evidence of an interaction until R+3, when the ISS group still had inflated variability, but not the STS group. Conclusions: Variability of the cardiovascular index W recovers more slowly after long-compared to short-duration spaceflight. Since high variability of W has also been shown to be predictive of OTT failure, a primary manifestation of OH, a logical conclusion is that recovery from OH also is slower after long-duration compared to short-duration spaceflights.

Birds and longevity: does flight driven aerobicity provide an oxidative sink?

PubMed

Hickey, Anthony J R; Jüllig, Mia; Aitken, Jacqueline; Loomes, Kerry; Hauber, Mark E; Phillips, Anthony R J

2012-04-01

Birds generally age slower and live longer than similar sized mammals. For birds this occurs despite elevated blood glucose levels that for mammals would in part define them as diabetic. However these data were acquired in respiration states that have little resemblance to conditions in healthy tissues and mitochondrial RS production is probably minimal in healthy animals. Indeed mitochondria probably act as net consumers rather than producers of RS. Here we propose that (1) if mitochondria are antioxidant systems, the greater mitochondrial mass in athletic species, such as birds, is advantageous as it should provide a substantial sink for RS. (2) The intense drive for aerobic performance and decreased body density to facilitate flight may explain the relative insensitivity of birds to insulin, as well as depressed insulin levels and apparent sensitization to glucagon. Glucagon also associates with the sirtuin protein family, most of which are associated with caloric restriction regulated pathways, mitochondrial biogenesis and life span extension. (3) We note that telomeres, which appear to be unusually long in birds, bind Sirtuins 2 and 4 and therefore may stabilize and protect nuclear DNA. Ultimately these flight driven responses may suppress somatic growth and protect DNA from oxidative damage that would otherwise lead to ageing and non-viral cancers. Copyright © 2011 Elsevier B.V. All rights reserved.

Surface regions of illusory images are detected with a slower processing speed than those of luminance-defined images.

PubMed

Mihaylova, Milena; Manahilov, Velitchko

2010-11-24

Research has shown that the processing time for discriminating illusory contours is longer than for real contours. We know, however, little whether the visual processes, associated with detecting regions of illusory surfaces, are also slower as those responsible for detecting luminance-defined images. Using a speed-accuracy trade-off (SAT) procedure, we measured accuracy as a function of processing time for detecting illusory Kanizsa-type and luminance-defined squares embedded in 2D static luminance noise. The data revealed that the illusory images were detected at slower processing speed than the real images, while the points in time, when accuracy departed from chance, were not significantly different for both stimuli. The classification images for detecting illusory and real squares showed that observers employed similar detection strategies using surface regions of the real and illusory squares. The lack of significant differences between the x-intercepts of the SAT functions for illusory and luminance-modulated stimuli suggests that the detection of surface regions of both images could be based on activation of a single mechanism (the dorsal magnocellular visual pathway). The slower speed for detecting illusory images as compared to luminance-defined images could be attributed to slower processes of filling-in of regions of illusory images within the dorsal pathway.

Homing pigeons (Columba livia) modulate wingbeat characteristics as a function of route familiarity.

PubMed

Taylor, Lucy A; Portugal, Steven J; Biro, Dora

2017-08-15

Mechanisms of avian navigation have received considerable attention, but whether different navigational strategies are accompanied by different flight characteristics is unknown. Managing energy expenditure is critical for survival; therefore, understanding how flight characteristics, and hence energy allocation, potentially change with birds' familiarity with a navigational task could provide key insights into the costs of orientation. We addressed this question by examining changes in the wingbeat characteristics and airspeed of homing pigeons ( Columba livia ) as they learned a homing task. Twenty-one pigeons were released 20 times individually either 3.85 or 7.06 km from home. Birds were equipped with 5 Hz GPS trackers and 200 Hz tri-axial accelerometers. We found that, as the birds' route efficiency increased during the first six releases, their median peak-to-peak dorsal body (DB) acceleration and median DB amplitude also increased. This, in turn, led to higher airspeeds, suggesting that birds fly slower when traversing unfamiliar terrain. By contrast, after route efficiency stabilised, birds exhibited increasing wingbeat frequencies, which did not result in further increases in speed. Overall, higher wind support was also associated with lower wingbeat frequencies and increased DB amplitude. Our study suggests that the cost of early flights from an unfamiliar location may be higher than subsequent flights because of both inefficient routes (increased distance) and lower airspeeds (increased time). Furthermore, the results indicate, for the first time, that birds modulate their wingbeat characteristics as a function of navigational knowledge, and suggest that flight characteristics may be used as 'signatures' of birds' route familiarity. © 2017. Published by The Company of Biologists Ltd.

Beta-2- Adrenergic Receptor Genotype and Other Variables that Contribute to Labor Pain and Progress

PubMed Central

Reitman, Elena; Conell-Price, Jessamyn; Evansmilth, Jennifer; Olson, Luke; Drosinos, Sofia; Jasper, Nancy; Randolph, Paula; Smiley, Richard; Shafer, Steven; Flood, Pamela

2011-01-01

Background Beta-2-adrenergic receptor (β2AR) activity influences labor and its genotype affects the incidence of preterm delivery. We determined the effect of β2AR genotype on term labor progress and pain. Methods We prospectively enrolled 150 nulliparous parturients in the third trimester and obtained sensory thresholds, demographic information and DNA. Cervical dilation, pain scores and labor management data were extracted with associated times. The association of genetic and demographic factors with labor was tested with mixed effects models. Results Parturients who express Gln at the 27 position of the β2AR had slower labor (P<0.03). They progressedfrom 1–10cm dilation in approximately 21 hours compared to 14 hours in otherpatients. Asian ethnicity, previously associated with slower labor, is highly associated with this polymorphism (P<0.0001). Heavier and Black patients had slower latent labor (P<0.01, 0.01) and neuraxial analgesia was associated with slower labor progress (P<0.0001). It could take up to 36 hours for the heaviest and the Black parturients to transition from 1cm cervical dilation to active labor; however once the active phase began, labor rate was the same as other patients’. Conclusion We detected a strong association between β2AR genotype and slower labor. Asian ethnicity may be a proxy for β2AR genotype. Black and heavy women have slower latent labor. These results confirm many of the associations found when this mathematical model was applied to a large retrospectivecohort, further validating this approach to description and analysis of labor progress. PMID:21394004

Subliminal semantic priming in speech.

PubMed

Daltrozzo, Jérôme; Signoret, Carine; Tillmann, Barbara; Perrin, Fabien

2011-01-01

Numerous studies have reported subliminal repetition and semantic priming in the visual modality. We transferred this paradigm to the auditory modality. Prime awareness was manipulated by a reduction of sound intensity level. Uncategorized prime words (according to a post-test) were followed by semantically related, unrelated, or repeated target words (presented without intensity reduction) and participants performed a lexical decision task (LDT). Participants with slower reaction times in the LDT showed semantic priming (faster reaction times for semantically related compared to unrelated targets) and negative repetition priming (slower reaction times for repeated compared to semantically related targets). This is the first report of semantic priming in the auditory modality without conscious categorization of the prime.

Subliminal Semantic Priming in Speech

PubMed Central

Tillmann, Barbara; Perrin, Fabien

2011-01-01

Numerous studies have reported subliminal repetition and semantic priming in the visual modality. We transferred this paradigm to the auditory modality. Prime awareness was manipulated by a reduction of sound intensity level. Uncategorized prime words (according to a post-test) were followed by semantically related, unrelated, or repeated target words (presented without intensity reduction) and participants performed a lexical decision task (LDT). Participants with slower reaction times in the LDT showed semantic priming (faster reaction times for semantically related compared to unrelated targets) and negative repetition priming (slower reaction times for repeated compared to semantically related targets). This is the first report of semantic priming in the auditory modality without conscious categorization of the prime. PMID:21655277

High manoeuvring costs force narrow-winged molossid bats to forage in open space.

PubMed

Voigt, Christian C; Holderied, Marc W

2012-04-01

Molossid bats are specialised aerial-hawkers that, like their diurnal ecological counterparts, swallows and swifts, hunt for insects in open spaces. The long and narrow wings of molossids are considered energetically adapted to fast flight between resource patches, but less suited for manoeuvring in more confined spaces, such as between tree-tops or in forest gaps. To understand whether a potential increase in metabolic costs of manoeuvring excludes molossids from foraging in more confined spaces, we measured energy costs and speed of manoeuvring flight in two tropical molossids, 18 g Molossus currentium and 23 g Molossus sinaloae, when flying in a ~500 m(3) hexagonal enclosure (~120 m(2) area), which is of similar dimensions as typical forest gaps. Flight metabolism averaged 10.21 ± 3.00 and 11.32 ± 3.54 ml CO(2) min(-1), and flight speeds 5.65 ± 0.47 and 6.27 ± 0.68 m s(-1) for M. currentium and M. sinaloae respectively. Metabolic rate during flight was higher for the M. currentium than for the similar-sized, but broader-winged frugivore Carollia sowelli, corroborating that broad-winged bats are better adapted to flying in confined spaces. These higher metabolic costs of manoeuvring flight may be caused by having to fly slower than the optimal foraging speed, and by the additional metabolic costs for centripetal acceleration in curves. This may preclude molossids from foraging efficiently between canopy trees or in forest gaps. The surprisingly brief burst of foraging activity at dusk of many molossids might be related to the cooling of the air column after sunset, which drives airborne insects to lower strata. Accordingly, foraging activity of molossids may quickly turn unprofitable when the abundance of insects decreases above the canopy.

Independently Controlled Wing Stroke Patterns in the Fruit Fly Drosophila melanogaster

PubMed Central

Chakraborty, Soma; Bartussek, Jan; Fry, Steven N.; Zapotocky, Martin

2015-01-01

Flies achieve supreme flight maneuverability through a small set of miniscule steering muscles attached to the wing base. The fast flight maneuvers arise from precisely timed activation of the steering muscles and the resulting subtle modulation of the wing stroke. In addition, slower modulation of wing kinematics arises from changes in the activity of indirect flight muscles in the thorax. We investigated if these modulations can be described as a superposition of a limited number of elementary deformations of the wing stroke that are under independent physiological control. Using a high-speed computer vision system, we recorded the wing motion of tethered flying fruit flies for up to 12 000 consecutive wing strokes at a sampling rate of 6250 Hz. We then decomposed the joint motion pattern of both wings into components that had the minimal mutual information (a measure of statistical dependence). In 100 flight segments measured from 10 individual flies, we identified 7 distinct types of frequently occurring least-dependent components, each defining a kinematic pattern (a specific deformation of the wing stroke and the sequence of its activation from cycle to cycle). Two of these stroke deformations can be associated with the control of yaw torque and total flight force, respectively. A third deformation involves a change in the downstroke-to-upstroke duration ratio, which is expected to alter the pitch torque. A fourth kinematic pattern consists in the alteration of stroke amplitude with a period of 2 wingbeat cycles, extending for dozens of cycles. Our analysis indicates that these four elementary kinematic patterns can be activated mutually independently, and occur both in isolation and in linear superposition. The results strengthen the available evidence for independent control of yaw torque, pitch torque, and total flight force. Our computational method facilitates systematic identification of novel patterns in large kinematic datasets. PMID:25710715

Independently controlled wing stroke patterns in the fruit fly Drosophila melanogaster.

PubMed

Chakraborty, Soma; Bartussek, Jan; Fry, Steven N; Zapotocky, Martin

2015-01-01

Flies achieve supreme flight maneuverability through a small set of miniscule steering muscles attached to the wing base. The fast flight maneuvers arise from precisely timed activation of the steering muscles and the resulting subtle modulation of the wing stroke. In addition, slower modulation of wing kinematics arises from changes in the activity of indirect flight muscles in the thorax. We investigated if these modulations can be described as a superposition of a limited number of elementary deformations of the wing stroke that are under independent physiological control. Using a high-speed computer vision system, we recorded the wing motion of tethered flying fruit flies for up to 12,000 consecutive wing strokes at a sampling rate of 6250 Hz. We then decomposed the joint motion pattern of both wings into components that had the minimal mutual information (a measure of statistical dependence). In 100 flight segments measured from 10 individual flies, we identified 7 distinct types of frequently occurring least-dependent components, each defining a kinematic pattern (a specific deformation of the wing stroke and the sequence of its activation from cycle to cycle). Two of these stroke deformations can be associated with the control of yaw torque and total flight force, respectively. A third deformation involves a change in the downstroke-to-upstroke duration ratio, which is expected to alter the pitch torque. A fourth kinematic pattern consists in the alteration of stroke amplitude with a period of 2 wingbeat cycles, extending for dozens of cycles. Our analysis indicates that these four elementary kinematic patterns can be activated mutually independently, and occur both in isolation and in linear superposition. The results strengthen the available evidence for independent control of yaw torque, pitch torque, and total flight force. Our computational method facilitates systematic identification of novel patterns in large kinematic datasets.

Unlabored system motion by specially conditioned electromagnetic fields in higher dimensional realms

NASA Astrophysics Data System (ADS)

David Froning, H.; Meholic, Gregory V.

2010-01-01

This third of three papers explores the possibility of swift, stress-less system transitions between slower-than-light and faster-than-light speeds with negligible net expenditure of system energetics. The previous papers derived a realm of higher dimensionality than 4-D spacetime that enabled such unlabored motion; and showed that fields that could propel and guide systems on unlabored paths in the higher dimensional realm must be fields that have been conditioned to SU(2) (or higher) Lie group symmetry. This paper shows that the system's surrounding vacuum dielectric ɛμ, within the higher dimensional realm's is a vector (not scalar) quantity with fixed magnitude ɛ0μ0 and changing direction within the realm with changing system speed. Thus, ɛμ generated by the system's EM field must remain tuned to vacuum ɛ0μ0 in both magnitude and direction during swift, unlabored system transitions between slower and faster than light speeds. As a result, the system's changing path and speed is such that the magnitude of the higher dimensional realm's ɛ0μ0 is not disturbed. And it is shown that a system's flight trajectories associated with its swift, unlabored transitions between zero and infinite speed can be represented by curved paths traced-out within the higher dimensional realm.

The influence of lower limb amputation level on the approach in the amputee long jump.

PubMed

Nolan, Lee; Lees, Adrian

2007-02-15

In this study, we investigated the adjustments to posture, kinematic and temporal characteristics of performance made by lower limb amputees during the last few strides in preparation for long jump take-off. Six male unilateral trans-femoral and seven male unilateral trans-tibial amputees competing in a World Championships final were filmed in the sagittal plane using a 100-Hz digital video camera positioned so that the last three strides to take-off were visible. After digitizing using a nine-segment model, a range of kinematic variables were computed to define technique characteristics. Both the trans-femoral and trans-tibial athletes appeared to achieve their reduction in centre of mass during the flight phase between strides, and did so mainly by extending the flight time by increasing stride length, achieved by a greater flexion of the hip joint of the touch-down leg. The trans-tibial athletes appeared to adopt a technique similar to that previously reported for able-bodied athletes. They lowered their centre of mass most on their second last stride (-1.6% of body height compared with -1.4% on the last stride) and used a flexed knee at take-off on the last stride, but they were less able to control their downward velocity at touch-down (-0.4 m x s(-1)). Both this and their restricted approach speed (8.9 m x s(-1) at touch-down), rather than technique limitations, influenced their jump performance. The trans-femoral athletes lowered their centre of mass most on the last stride (-2.3% of body height compared with -1.6% on the second last stride) and, as they were unable to flex their prosthetic knee sufficiently, achieved this by abducting their prosthetic leg during the support phase, which led to a large downward velocity at touch-down (-0.6 m x s(-1)). This, combined with their slower approach velocity (7.1 m x s(-1) at touch-down), restricted their performance.

Enhanced tethered-flight duration and locomotor activity by overexpression of the human gene SOD1 in Drosophila motorneurons.

PubMed

Petrosyan, Agavni; Hsieh, I-Hui; Phillips, John P; Saberi, Kourosh

2015-03-01

Mutation of the human gene superoxide dismutase (hSOD1) is associated with the fatal neurodegenerative disease familial amyotrophic lateral sclerosis (Lou Gehrig's disease). Selective overexpression of hSOD1 in Drosophila motorneurons increases lifespan to 140% of normal. The current study was designed to determine resistance to lifespan decline and failure of sensorimotor functions by overexpressing hSOD1 in Drosophila's motorneurons. First, we measured the ability to maintain continuous flight and wingbeat frequency (WBF) as a function of age (5 to 50 days). Flies overexpressing hSOD1 under the D42-GAL4 activator were able to sustain flight significantly longer than controls, with the largest effect observed in the middle stages of life. The hSOD1-expressed line also had, on average, slower wingbeat frequencies in late, but not early life relative to age-matched controls. Second, we examined locomotor (exploratory walking) behavior in late life when flies had lost the ability to fly (age ≥ 60 d). hSOD1-expressed flies showed significantly more robust walking activity relative to controls. Findings show patterns of functional decline dissimilar to those reported for other life-extended lines, and suggest that the hSOD1 gene not only delays death but enhances sensorimotor abilities critical to survival even in late life.

Sedation and physiologic response to manual restraint after intranasal administration of midazolam in Hispaniolan Amazon parrots (Amazona ventralis).

PubMed

Mans, Christoph; Guzman, David Sanchez-Migallon; Lahner, Lesanna L; Paul-Murphy, Joanne; Sladky, Kurt K

2012-09-01

Administration of intranasal midazolam (2 mg/kg) was evaluated for sedation and effects on cloacal temperature, respiratory rate, and heart rate in manually restrained Hispaniolan Amazon parrots (Amazona ventralis). Adult parrots (n=9) were administered either midazolam (2 mg/kg) or an equal volume of saline solution intranasally before a 15-minute manual restraint in a complete crossover study. Respiratory rate and sedation scores were recorded before and during capture and during and after 15 minutes of manual restraint. Heart rate and cloacal temperature were recorded during manual restraint. After restraint, the parrots received intranasal flumazenil (0.05 mg/kg) or an equal volume of saline solution, and the recovery time was recorded. In those birds that received midazolam, sedation was observed within 3 minutes of administration, and vocalization, flight, and defense responses were significantly reduced during capture. During manual restraint, the mean rate of cloacal temperature increase was significantly slower and remained significantly lower in birds that received midazolam compared with controls. Mean respiratory rates were significantly lower for up to 12 minutes in parrots that received midazolam compared with those receiving saline solution. Flumazenil antagonized the effects of midazolam within 10 minutes. No overt clinical adverse effects to intranasal midazolam and flumazenil administration were observed. Further studies on the safety of intranasal midazolam and flumazenil in this species are warranted.

The Effects of Attentional Engagement on Route Learning Performance in a Virtual Environment: An Aging Study

PubMed Central

Hartmeyer, Steffen; Grzeschik, Ramona; Wolbers, Thomas; Wiener, Jan M.

2017-01-01

Route learning is a common navigation task affected by cognitive aging. Here we present a novel experimental paradigm to investigate whether age-related declines in executive control of attention contributes to route learning deficits. A young and an older participant group was repeatedly presented with a route through a virtual maze comprised of 12 decision points (DP) and non-decision points (non-DP). To investigate attentional engagement with the route learning task, participants had to respond to auditory probes at both DP and non-DP. Route knowledge was assessed by showing participants screenshots or landmarks from DPs and non-DPs and asking them to indicate the movement direction required to continue the route. Results demonstrate better performance for DPs than for non-DPs and slower responses to auditory probes at DPs compared to non-DPs. As expected we found slower route learning and slower responses to the auditory probes in the older participant group. Interestingly, differences in response times to the auditory probes between DPs and non-DPs can predict the success of route learning in both age groups and may explain slower knowledge acquisition in the older participant group. PMID:28775689

Uptake of Sulfate but Not Phosphate by Mycobacterium tuberculosis Is Slower than That for Mycobacterium smegmatis

PubMed Central

Song, Houhui

2012-01-01

Knowledge of the metabolic pathways used by Mycobacterium tuberculosis during infection is important for understanding its nutrient requirements and host adaptation. However, uptake, the first step in the utilization of nutrients, is poorly understood for many essential nutrients, such as inorganic anions. Here, we show that M. tuberculosis utilizes nitrate as the sole nitrogen source, albeit at lower efficiency than asparagine, glutamate, and arginine. The growth of the porin triple mutant M. smegmatis ML16 in media with limiting amounts of nitrate and sulfate as sole nitrogen and sulfur sources, respectively, was delayed compared to that of the wild-type strain. The uptake of sulfate was 40-fold slower than that of the wild-type strain, indicating that the efficient uptake of these anions is dependent on porins. The uptake by M. tuberculosis of sulfate and phosphate was approximately 40- and 10-fold slower than that of M. smegmatis, respectively, which is consistent with the slower growth of M. tuberculosis. However, the uptake of these anions by M. tuberculosis is orders of magnitude faster than diffusion through lipid membranes, indicating that unknown outer membrane proteins are required to facilitate this process. PMID:22194452

Self-organization in a bimotility mixture of model microswimmers

NASA Astrophysics Data System (ADS)

Agrawal, Adyant; Babu, Sujin B.

2018-02-01

We study the cooperation and segregation dynamics in a bimotility mixture of microorganisms which swim at low Reynolds numbers via periodic deformations along the body. We employ a multiparticle collision dynamics method to simulate a two component mixture of artificial swimmers, termed as Taylor lines, which differ from each other only in the propulsion speed. The analysis reveals that a contribution of slower swimmers towards clustering, on average, is much larger as compared to the faster ones. We notice distinctive self-organizing dynamics, depending on the percentage difference in the speed of the two kinds. If this difference is large, the faster ones fragment the clusters of the slower ones in order to reach the boundary and form segregated clusters. Contrarily, when it is small, both kinds mix together at first, the faster ones usually leading the cluster and then gradually the slower ones slide out thereby also leading to segregation.

Auditory perceptual simulation: Simulating speech rates or accents?

PubMed

Zhou, Peiyun; Christianson, Kiel

2016-07-01

When readers engage in Auditory Perceptual Simulation (APS) during silent reading, they mentally simulate characteristics of voices attributed to a particular speaker or a character depicted in the text. Previous research found that auditory perceptual simulation of a faster native English speaker during silent reading led to shorter reading times that auditory perceptual simulation of a slower non-native English speaker. Yet, it was uncertain whether this difference was triggered by the different speech rates of the speakers, or by the difficulty of simulating an unfamiliar accent. The current study investigates this question by comparing faster Indian-English speech and slower American-English speech in the auditory perceptual simulation paradigm. Analyses of reading times of individual words and the full sentence reveal that the auditory perceptual simulation effect again modulated reading rate, and auditory perceptual simulation of the faster Indian-English speech led to faster reading rates compared to auditory perceptual simulation of the slower American-English speech. The comparison between this experiment and the data from Zhou and Christianson (2016) demonstrate further that the "speakers'" speech rates, rather than the difficulty of simulating a non-native accent, is the primary mechanism underlying auditory perceptual simulation effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Megachiropteran bats profoundly unique from microchiropterans in climbing and walking locomotion: Evolutionary implications

PubMed Central

Carter, Richard T.

2017-01-01

Understandably, most locomotor analyses of bats have focused on flight mechanics and behaviors. However, we investigated nonflight locomotion in an effort to glean deeper insights into the evolutionary history of bats. We used high-speed video (300 Hz) to film and compare walking and climbing mechanics and kinematics between several species of the suborders Megachiroptera (Pteropodidae) versus Microchiroptera (Vespertilionidae and Phyllostomatidae). We found fundamentally distinctive behaviors, functional abilities, and performance outcomes between groups, but nearly homogeneous outcomes within groups. Megachiropterans exhibited climbing techniques and skills not found in microchiropterans and which aligned with other fully arboreal mammals. Megachiropterans climbed readily when placed in a head-up posture on a vertical surface, showed significantly greater ability than microchiropterans to abduct and extend the reach of their limbs, and climbed at a greater pace by using a more aggressive ipsilateral gait, at times being supported by only a single contact point. In addition, megachiropterans showed little ability to employ basic walking mechanics when placed on the ground, also a pattern observed in some highly adapted arboreal mammals. Conversely, microchiropterans resisted climbing vertical surfaces in a head-up posture, showed significantly less extension of their limbs, and employed a less-aggressive, slower contralateral gait with three points of contact. When walking, microchiropterans used the same gait they did when climbing which is representative of basic tetrapod terrestrial mechanics. Curiously, megachiropterans cycled their limbs significantly faster when climbing than when attempting to walk, whereas microchiropterans cycled their limbs at significantly faster rates when walking than when climbing. We contend that nonflight locomotion mechanics give a deep evolutionary view into the ancestral es locomotor platform on which flight was built in each of these groups. PMID:28957404

Orion Pad Abort 1 Flight Test: Simulation Predictions Versus Flight Data

NASA Technical Reports Server (NTRS)

Stillwater, Ryan Allanque; Merritt, Deborah S.

2011-01-01

The presentation covers the pre-flight simulation predictions of the Orion Pad Abort 1. The pre-flight simulation predictions are compared to the Orion Pad Abort 1 flight test data. Finally the flight test data is compared to the updated simulation predictions, which show a ove rall improvement in the accuracy of the simulation predictions.

Stability of Silica- and Enzyme-Treated Palm Oil Under Deep Frying Conditions.

PubMed

Karim, Nur Azwani Ab; Noor, Ahmadilfitri Md; Lee, Yee-Ying; Lai, Oi-Ming

2015-12-01

The oxidative and thermal stability of low diglycerides palm oil produced via silica treatment (sPO) and enzymatic treatment (ePO) compared with standard quality palm oil (SQ) and premium quality palm oil (PQ) was investigated. Both of the oils displayed better oxidative stability compared with SQ as well as significantly higher (P < 0.05) thermal resistance and oxidative strength than SQ and PQ due to lower amounts of partial glycerides. Although the initial induction periods (IPs) of sPO and ePO were significantly lower compared with SQ and PQ, both the oils showed slower drops in their IP values. The darkening effect after frying was significantly (P < 0.05) slower in sPO compared with SQ, PQ, and ePO. Besides, there is no difference p > 0.05 in the rate of FFA formation between sPO and PQ. The anisidine value and peroxide values were lowest in sPO, followed by ePO, PQ, and SQ. © 2015 Institute of Food Technologists®

Body saccades of Drosophila consist of stereotyped banked turns.

PubMed

Muijres, Florian T; Elzinga, Michael J; Iwasaki, Nicole A; Dickinson, Michael H

2015-03-01

The flight pattern of many fly species consists of straight flight segments interspersed with rapid turns called body saccades, a strategy that is thought to minimize motion blur. We analyzed the body saccades of fruit flies (Drosophila hydei), using high-speed 3D videography to track body and wing kinematics and a dynamically scaled robot to study the production of aerodynamic forces and moments. Although the size, degree and speed of the saccades vary, the dynamics of the maneuver are remarkably stereotypic. In executing a body saccade, flies perform a quick roll and counter-roll, combined with a slower unidirectional rotation around their yaw axis. Flies regulate the size of the turn by adjusting the magnitude of torque that they produce about these control axes, while maintaining the orientation of the rotational axes in the body frame constant. In this way, body saccades are different from escape responses in the same species, in which the roll and pitch component of banking is varied to adjust turn angle. Our analysis of the wing kinematics and aerodynamics showed that flies control aerodynamic torques during the saccade primarily by adjusting the timing and amount of span-wise wing rotation. © 2015. Published by The Company of Biologists Ltd.

Optimal profit of the parasitation by Aphelinus mali in an IPM complementary strategy for the control of Eriosoma lanigerum.

PubMed

Goossens, D; Bangels, E; Belien, T; Schoevaerts, C; De Maeyer, L

2011-01-01

During summer the parasitoid Aphelinus mali may certainly reduce the infestation of woolly apple aphid (Eriosoma lanigerum), but studies on the single interaction rarely indicate sufficient biological control in the period May-June. In this period chemical control by spirotetramat or pirimicarb remains indispensable in order to anticipate on dense migration waves and subsequent colonization of extension shoots by E. lanigerum. The limited parasitation by A. mali around flowering is linked with a delayed emergence from diapause and with a slower reproduction rate than its host. In 2010 and 2011 the first adult flights monitored on yellow sticky traps corresponded perfectly with the currently used prediction models for A. mali. Further accurate monitoring all along the season enabled also to determine a well defined endo-parasitic phase of A. mali occurring after the small peak observed around flowering. During this endo-parasitic phase A. mali larvae reside inside their mummified host. Compounds with higher acute toxicity on A. mali adults, like chloronicotinyl insecticides (CNI's), are preferably positioned here. Selectivity in the time can then be claimed. Respecting this principle, the further parasitation potential of A. mali in summer is not hampered. Preservation of the first peak of flights of A. mali in the pre-flowering period is essential for an exponential flight increase. This is essential for the parasitation of E. lanigerum in summer, which constitutes a valuable complement in the integrated control strategy.

The behavior of an opponent alters pacing decisions in 4-km cycling time trials.

PubMed

Konings, Marco J; Schoenmakers, Patrick P J M; Walker, Andrew J; Hettinga, Florentina J

2016-05-01

The present study aimed to explore how athletes respond to different behaviors of their opponents. Twelve moderately to highly physically active participants with at least two years of cycling experience completed four 4-km time trials on a Velotron cycle ergometer. After a familiarization time trial (FAM), participants performed three experimental time trials in randomized order with no opponent (NO), a virtual opponent who started slower and finished faster compared to FAM (OP-SLOWFAST), or a virtual opponent who started faster and finished slower compared to FAM (OP-FASTSLOW). Repeated-measures ANOVAs (P<0.05) were used to examine differences in pacing and performance related to power output, velocity and RPE. OP-SLOWFAST and OP-FASTSLOW were completed faster compared to NO (385.5±27.5, 385.0±28.6, and 390.6±29.3s, respectively). An interaction effect for condition×distance (F=3.944, P<0.001) indicated differences in pacing profiles between conditions. Post-hoc analysis revealed that a less aggressive starting strategy was adopted in NO compared to OP-FASTSLOW and OP-SLOWFAST during the initial 1000m. Finally, a faster starting opponent evokes higher power outputs by the participants in the initial 750m compared to a slower starting opponent. The present study is the first to show that the behavior of an opponent affects pacing-related decisions in laboratory-controlled conditions. Our findings support the recently proposed interdependence of perception and action, and emphasize the interaction with the environment as an important determinant for an athlete's pacing decisions, especially during the initial stages of a race. Copyright © 2016 Elsevier Inc. All rights reserved.

Slow but not low: genomic comparisons reveal slower evolutionary rate and higher dN/dS in conifers compared to angiosperms.

PubMed

Buschiazzo, Emmanuel; Ritland, Carol; Bohlmann, Jörg; Ritland, Kermit

2012-01-20

Comparative genomics can inform us about the processes of mutation and selection across diverse taxa. Among seed plants, gymnosperms have been lacking in genomic comparisons. Recent EST and full-length cDNA collections for two conifers, Sitka spruce (Picea sitchensis) and loblolly pine (Pinus taeda), together with full genome sequences for two angiosperms, Arabidopsis thaliana and poplar (Populus trichocarpa), offer an opportunity to infer the evolutionary processes underlying thousands of orthologous protein-coding genes in gymnosperms compared with an angiosperm orthologue set. Based upon pairwise comparisons of 3,723 spruce and pine orthologues, we found an average synonymous genetic distance (dS) of 0.191, and an average dN/dS ratio of 0.314. Using a fossil-established divergence time of 140 million years between spruce and pine, we extrapolated a nucleotide substitution rate of 0.68 × 10(-9) synonymous substitutions per site per year. When compared to angiosperms, this indicates a dramatically slower rate of nucleotide substitution rates in conifers: on average 15-fold. Coincidentally, we found a three-fold higher dN/dS for the spruce-pine lineage compared to the poplar-Arabidopsis lineage. This joint occurrence of a slower evolutionary rate in conifers with higher dN/dS, and possibly positive selection, showcases the uniqueness of conifer genome evolution. Our results are in line with documented reduced nucleotide diversity, conservative genome evolution and low rates of diversification in conifers on the one hand and numerous examples of local adaptation in conifers on the other hand. We propose that reduced levels of nucleotide mutation in large and long-lived conifer trees, coupled with large effective population size, were the main factors leading to slow substitution rates but retention of beneficial mutations.

Identification of atypical flight patterns

NASA Technical Reports Server (NTRS)

Statler, Irving C. (Inventor); Ferryman, Thomas A. (Inventor); Amidan, Brett G. (Inventor); Whitney, Paul D. (Inventor); White, Amanda M. (Inventor); Willse, Alan R. (Inventor); Cooley, Scott K. (Inventor); Jay, Joseph Griffith (Inventor); Lawrence, Robert E. (Inventor); Mosbrucker, Chris (Inventor)

2005-01-01

Method and system for analyzing aircraft data, including multiple selected flight parameters for a selected phase of a selected flight, and for determining when the selected phase of the selected flight is atypical, when compared with corresponding data for the same phase for other similar flights. A flight signature is computed using continuous-valued and discrete-valued flight parameters for the selected flight parameters and is optionally compared with a statistical distribution of other observed flight signatures, yielding atypicality scores for the same phase for other similar flights. A cluster analysis is optionally applied to the flight signatures to define an optimal collection of clusters. A level of atypicality for a selected flight is estimated, based upon an index associated with the cluster analysis.

Feasibility of using S-191 infrared spectra for geological studies from space

NASA Technical Reports Server (NTRS)

Lyon, R. J. P.

1976-01-01

Use of the S-191 spectrometer system aboard the SKYLAB(SL3) mission shows that geologically meaningful spectra can be extracted from the data by which terrain target can be differentiated. The Si-O bond in all silicates (which form most surface rocks) produced an emission minimum which is characteristic of a mineral, or a set of minerals, in a rock. The underflight RB57 mission was far more successful, primarily because of its much slower velocity allowing a higher signal/noise, and hence better spectral resolution for any given area terrain. With the RB57 spectra, areas can be differentiated and significant differences in rock targets demonstrated. The geological provenance of some alluvial outwash in the nearby mountains over which the aircraft also flew its flight strip can be indicated.

KSC-2009-4413

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. –Space shuttle Discovery nears Launch Pad 39A at NASA's Kennedy Space Center in Florida. First motion out of the Vehicle Assembly Building was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. The 3.4-mile journey was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Dimitri Gerondidakis

Voluntary sway and rapid orthogonal transitions of voluntary sway in young adults, and low and high fall-risk older adults.

PubMed

Tucker, Murray G; Kavanagh, Justin J; Morrison, Steven; Barrett, Rod S

2009-10-01

Falls amongst older people have been linked to reduced postural stability and slowed movement responses. The objective of this study was to examine differences in postural stability and the speed of response between young adults, low fall-risk older adults, and high fall-risk older adults during voluntary postural sway movements. Twenty-five young adults (25+/-4 years), and 32 low fall-risk (74+/-5 years), and 16 high fall-risk (79+/-7 years) older adults performed voluntary sway and rapid orthogonal transitions of voluntary sway between the anterior-posterior and medial-lateral directions. Measures included reaction and movement time and the amplitudes of the centre of pressure, centre of mass, and the separation distance between the centre of pressure and centre of mass. Both fall-risk groups compared to the young had slower reaction and movement time, greater centre of pressure and/or centre of mass amplitude in the orthogonal (non-target) direction during voluntary sway, and reduced anterior-posterior and medial-lateral separation between the centre of pressure and centre of mass during voluntary sway and orthogonal transitions. High compared to low fall-risk individuals had slower reaction and movement time, increased non-target centre of mass amplitude during voluntary sway, and reduced medial-lateral centre of pressure and centre of mass separation during voluntary sway and orthogonal transitions. Age-related deterioration of postural control resulted in slower reactive responses and reduced control of the direction of body movement during voluntary sway and orthogonal transitions. Slower postural reaction and movement time and reduced medial-lateral control of the centre of mass during voluntary sway movements are associated with increased fall-risk in community-living older people.

Elite long jumpers with below the knee prostheses approach the board slower, but take-off more effectively than non-amputee athletes.

PubMed

Willwacher, Steffen; Funken, Johannes; Heinrich, Kai; Müller, Ralf; Hobara, Hiroaki; Grabowski, Alena M; Brüggemann, Gert-Peter; Potthast, Wolfgang

2017-11-22

The use of technological aids to improve sport performance ('techno doping') and inclusion of Paralympic athletes in Olympic events are matters of ongoing debate. Recently, a long jumper with a below the knee amputation (BKA) achieved jump distances similar to world-class athletes without amputations, using a carbon fibre running-specific prosthesis (RSP). We show that athletes with BKA utilize a different, more effective take-off technique in the long jump, which provided the best athlete with BKA a performance advantage of at least 0.13 m compared to non-amputee athletes. A maximum speed constraint imposed by the use of RSPs would indicate a performance disadvantage for the long jump. We found slower maximum sprinting speeds in athletes with BKA, but did not find a difference in the overall vertical force from both legs of athletes with BKA compared to non-amputees. Slower speeds might originate from intrinsically lower sprinting abilities of athletes with BKA or from more complex adaptions in sprinting mechanics due to the biomechanical and morphological differences induced by RSPs. Our results suggest that due to different movement strategies, athletes with and without BKA should likely compete in separate categories for the long jump.

Discriminative evaluative conditioning in the long-term after severe accidental injury.

PubMed

Oe, Misari; Schumacher, Sonja; Schnyder, Ulrich; Mueller-Pfeiffer, Christoph; Wilhelm, Frank H; Kuelen, Eveline; Martin-Soelch, Chantal

2016-06-30

Impairments in classical fear conditioning and deficits in discriminative learning are observed in posttraumatic stress disorder (PTSD). However, it is unknown whether similar impairments can be found with types of discriminative learning other than classical conditioning, such as evaluative conditioning (EC), in which the valence of a stimulus can be transferred to other stimuli. In this study, we investigated whether EC is also influenced by traumatic experiences independently of presence of PTSD. We tested 14 accident survivors with remitted PTSD, 14 survivors without PTSD, and 16 non-trauma controls. We used behavioral measures, psychophysiological indicators, and subjective ratings for tasks. General effects of learning were observed across groups and conditioning/extinction. Trauma controls had slower reaction times (RTs) to the aversive conditioned stimulus compared to appetitive conditioned and neutral stimuli, as well as slower RTs and increased accuracy during conditioning than during extinction. Remitted PTSD participants showed opposite results, demonstrating decreased accuracy and slower RTs during conditioning as compared to during extinction. No discriminative effect was found in the non-trauma controls and the remitted PTSD participants. These results suggest that a traumatic experience influences EC, and that this influence differs between individuals who have and have not developed PTSD after traumatic exposure. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Gender differences in scalp hair growth rates are maintained but reduced in pattern hair loss compared to controls.

PubMed

Van Neste, D J J; Rushton, D H

2016-08-01

Hair loss is related to follicular density, programmed regrowth and hair productivity. The dissatisfaction with hair growth in patients experiencing hair loss might be due to slower linear hair growth rate (LHGR). LHGR and hair diameter was evaluated in Caucasian controls and patients with patterned hair loss employing the validated non-invasive, contrast-enhanced-phototrichogram with exogen collection. We evaluated 59,765 anagen hairs (controls 24,609, patients 35,156) and found thinner hairs grew slower than thicker hairs. LHGR in normal women was generally higher than in normal men. LHGR correlates with hair diameter (P < 0.006) and global thinning is associated with slower growth rates. Compared with hair of equal thickness in controls, subjects affected with patterned hair loss showed reduced hair growth rates, an observation found in both male and female patients. Males with pattern hair loss showed further reduction in growth rates as clinical severity worsened. However, sample size limitations prevented statistical evaluation of LHGR in severely affected females. Caucasian ethnicity. In pattern hair loss, LHGR significantly contributes to the apparent decrease in hair volume in affected areas. In early onset, LHRG might have a prognostic value in females but not in males. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Negative effects of microplastic exposure on growth and development of Crepidula onyx.

PubMed

Lo, Hau Kwan Abby; Chan, Kit Yu Karen

2018-02-01

Microplastics exposure could be detrimental to marine organisms especially under high concentrations. However, few studies have considered the multiphasic nature of marine invertebrates' life history and investigated the impact of experiencing microplastics during early development on post-metamorphic stages (legacy effect). Many planktonic larvae can feed selectively and it is unclear whether such selectivity could modulate the impact of algal food-sized microplastic. In this two-stage experiment, veligers of Crepidula onyx were first exposed to additions of algae-sized micro-polystyrene (micro-PS) beads at different concentrations, including ones that were comparable their algal diet. These additions were then either halted or continued after settlement. At environmentally relevant concentration (ten 2-μm microplastic beads ml -1 ), larval and juvenile C. onyx was not affected. At higher concentrations, these micro-PS fed larvae consumed a similar amount of algae compared to those in control but grew relatively slower than those in the control suggesting that ingestion and/or removal of microplastic was/were energetically costly. These larvae also settled earlier at a smaller size compared to the control, which could negatively affect post-settlement success. Juvenile C. onyx receiving continuous micro-PS addition had slower growth rates. Individuals only exposed to micro-PS during their larval stage continued to have slower growth rates than those in the control even if micro-PS had been absent in their surroundings for 65 days highlighting a legacy effect of microplastic exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of theoretical and flight-measured local flow aerodynamics for a low-aspect-ratio fin

NASA Technical Reports Server (NTRS)

Johnson, J. B.; Sandlin, D. R.

1984-01-01

Flight test and theoretical aerodynamic data were obtained for a flight test fixture mounted on the underside of an F-104G aircraft. The theoretical data were generated using two codes, a two dimensional transonic code called Code H, and a three dimensional subsonic and supersonic code call wing-body. Pressure distributions generated by the codes for the flight test fixture as well as boundary layer displacement thickness generated by the two dimensional code were compared to the flight test data. The two dimensional code pressure distributions compared well except at the minimum pressure point and trailing edge. Shock locations compared well except at high transonic speeds. The three dimensional code pressure distributions compared well except at the trailing edge of the flight test fixture. The two dimensional code does not predict displacement thickness of the flight test fixture well.

National health spending in 2013: growth slows, remains in step with the overall economy.

PubMed

Hartman, Micah; Martin, Anne B; Lassman, David; Catlin, Aaron

2015-01-01

In 2013 US health care spending increased 3.6 percent to $2.9 trillion, or $9,255 per person. The share of gross domestic product devoted to health care spending has remained at 17.4 percent since 2009. Health care spending decelerated 0.5 percentage point in 2013, compared to 2012, as a result of slower growth in private health insurance and Medicare spending. Slower growth in spending for hospital care, investments in medical structures and equipment, and spending for physician and clinical care also contributed to the low overall increase. Project HOPE—The People-to-People Health Foundation, Inc.

Gentle vs. aversive handling of pregnant ewes: II. Physiology and behavior of the lambs.

PubMed

Coulon, M; Hild, S; Schroeer, A; Janczak, A M; Zanella, A J

2011-07-06

We compared the effects of aversive and gentle handling in late pregnant ewes on fearfulness, heart rate variability and spatial learning in lambs. Twenty-four Norwegian-Dala ewes were studied. Ewes were subjected to gentle (i.e. soft talking and calm behavior) or aversive handling (i.e. swift movements and shouting) for 10 min twice a day during the last five weeks of pregnancy. Lambs from aversively (AVS) or gently (GEN) treated ewes were tested at 4 weeks of age. Lamb behavior was recorded during a) a human approach test, composed of 4 min of isolation and 4 min of exposure to an unfamiliar human, b) an umbrella startle test followed by 5-min recording, and c) two repetitions of a maze test. In addition, heart rate variability was recorded telemetrically before and after the human and startle tests. The baseline heart rate variability measures suggested a lower influence of vagal stimulation in AVS lambs. In the human approach test, AVS lambs vocalized and explored the environment less, and were slower to approach the human. They also tended to have higher flight distances during the startle test than the GEN lambs. The prenatal treatment had no significant effect in the maze test. In conclusion, we showed that aversive handling of pregnant ewes increased fearfulness and reduced vagal tone in their progeny compared to GEN lambs. These effects can have consequences for how lambs cope with rearing conditions. Copyright © 2011 Elsevier Inc. All rights reserved.

Development of Hydroxyl Tagging Velocimetry for Low Velocity Flows

NASA Technical Reports Server (NTRS)

Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

2016-01-01

Hydroxyl tagging velocimetry (HTV) is a molecular tagging technique that relies on the photo-dissociation of water vapor into OH radicals and their subsequent tracking using laser induced fluorescence. Velocities are then obtained from time-of-flight calculations. At ambient temperature in air, the OH species lifetime is relatively short (<50 µs), making it suited for high speed flows. Lifetime and radicals formation increases with temperature, which allows HTV to also probe low-velocity, high-temperature flows or reacting flows such as flames. The present work aims at extending the domain of applicability of HTV, particularly towards low-speed (<10 m/s) and moderate (<500 K) temperature flows. Results are compared to particle image velocimetry (PIV) measurements recorded in identical conditions. Single shot and averaged velocity profiles are obtained in an air jet at room temperature. By modestly raising the temperature (100-200 degC) the OH production increases, resulting in an improvement of the signal-to-noise ratio (SNR). Use of nitrogen - a non-reactive gas with minimal collisional quenching - extends the OH species lifetime (to over 500 µs), which allows probing of slower flows or, alternately, increases the measurement precision at the expense of spatial resolution. Instantaneous velocity profiles are resolved in a 100degC nitrogen jet (maximum jet-center velocity of 6.5 m/s) with an uncertainty down to 0.10 m/s (1.5%) at 68% confidence level. MTV measurements are compared with particle image velocimetry and show agreement within 2%.

Velocity Measurement in a Dual-Mode Supersonic Combustor using Particle Image Velocimetry

NASA Technical Reports Server (NTRS)

Goyne, C. P.; McDaniel, J. C.; Krauss, R. H.; Day, S. W.; Reubush, D. E. (Technical Monitor); McClinton, C. R. (Technical Monitor); Reubush, D. E.

2001-01-01

Temporally and spatially-resolved, two-component measurements of velocity in a supersonic hydrogen-air combustor are reported. The combustor had a single unswept ramp fuel injector and operated with an inlet Mach number of 2 and a flow total temperature approaching 1200 K. The experiment simulated the mixing and combustion processes of a dual-mode scramjet operating at a flight Mach number near 5. The velocity measurements were obtained by seeding the fuel with alumina particles and performing Particle Image Velocimetry on the mixing and combustion wake of the ramp injector. To assess the effects of combustion on the fuel air-mixing process, the distribution of time-averaged velocity and relative turbulence intensity was determined for the cases of fuel-air mixing and fuel-air reacting. Relative to the mixing case, the near field core velocity of the reacting fuel jet had a slower streamwise decay. In the far field, downstream of 4 to 6 ramp heights from the ramp base, the heat release of combustion resulted in decreased flow velocity and increased turbulence levels. The reacting measurements were also compared with a computational fluid dynamics solution of the flow field. Numerically predicted velocity magnitudes were higher than that measured and the jet penetration was lower.

Space shuttle orbiter leading-edge flight performance compared to design goals

NASA Technical Reports Server (NTRS)

Curry, D. M.; Johnson, D. W.; Kelly, R. E.

1983-01-01

Thermo-structural performance of the Space Shuttle orbiter Columbia's leading-edge structural subsystem for the first five (5) flights is compared with the design goals. Lessons learned from thse initial flights of the first reusable manned spacecraft are discussed in order to assess design maturity, deficiencies, and modifications required to rectify the design deficiencies. Flight data and post-flight inspections support the conclusion that the leading-edge structural subsystem hardware performance was outstanding for the initial five (5) flights.

Sociomoral Reasoning in Congenitally Deaf Children as a Function of Cognitive Maturity.

ERIC Educational Resources Information Center

Markoulis, Diomedes; Christoforou, Maria

1991-01-01

Compares the operational and sociomoral reasoning maturity of 70 deaf children with that of a sensory unimpaired control sample. Tests subjects individually on three Piagetian tasks, story pairs, and the concept of justice. Finds slower development of operational reasoning in the deaf children but comparable development in sociomoral reasoning.…

Visual Processing of Verbal and Nonverbal Stimuli in Adolescents with Reading Disabilities.

ERIC Educational Resources Information Center

Boden, Catherine; Brodeur, Darlene A.

1999-01-01

A study investigated whether 32 adolescents with reading disabilities (RD) were slower at processing visual information compared to children of comparable age and reading level, or whether their deficit was specific to the written word. Adolescents with RD demonstrated difficulties in processing rapidly presented verbal and nonverbal visual…

The effect of different brightness conditions on visually and memory guided saccades.

PubMed

Felßberg, Anna-Maria; Dombrowe, Isabel

2018-01-01

It is commonly assumed that saccades in the dark are slower than saccades in a lit room. Early studies that investigated this issue using electrooculography (EOG) often compared memory guided saccades in darkness to visually guided saccades in an illuminated room. However, later studies showed that memory guided saccades are generally slower than visually guided saccades. Research on this topic is further complicated by the fact that the different existing eyetracking methods do not necessarily lead to consistent measurements. In the present study, we independently manipulated task (memory guided/visually guided) and screen brightness (dark, medium and light) in an otherwise completely dark room, and measured the peak velocity and the duration of the participant's saccades using a popular pupil-cornea reflection (p-cr) eyetracker (Eyelink 1000). Based on a critical reading of the literature, including a recent study using cornea-reflection (cr) eye tracking, we did not expect any velocity or duration differences between the three brightness conditions. We found that memory guided saccades were generally slower than visually guided saccades. In both tasks, eye movements on a medium and light background were equally fast and had similar durations. However, saccades on the dark background were slower and had shorter durations, even after we corrected for the effect of pupil size changes. This means that this is most likely an artifact of current pupil-based eye tracking. We conclude that the common assumption that saccades in the dark are slower than in the light is probably not true, however pupil-based eyetrackers tend to underestimate the peak velocity of saccades on very dark backgrounds, creating the impression that this might be the case. Copyright © 2017 Elsevier Ltd. All rights reserved.

Association of Family History of Exceptional Longevity With Decline in Physical Function in Aging.

PubMed

Ayers, Emmeline; Barzilai, Nir; Crandall, Jill P; Milman, Sofiya; Verghese, Joe

2017-11-09

Although many genetic and nongenetic factors interact to determine an individual's physical phenotype, there has been limited examination of the contribution of family history of exceptional parental longevity on decline in physical function in aging. The LonGenity study recruited a relatively genetically homogenous cohort of Ashkenazi Jewish adults age 65 and older, who were defined as either offspring of parents with exceptional longevity ([OPEL]: having at least one parent who lived to age 95 or older) or offspring of parents with usual survival ([OPUS]: neither parent survived to age 95). Decline in performance on objective measures of strength (grip strength), balance (unipedal stance), and mobility (gait speed) as well as a composite physical function measure, the Short physical performance battery (SPPB), were compared between the two groups over a median follow-up of 3.2 years, accounting for age, sex, education, and comorbidities. Of the 984 LonGenity participants (mean age 76, 55% women), 448 were OPEL and 536 were OPUS. Compared to OPUS, OPEL had slower decline on measures of unipedal stance (-0.03 log-units/year, p = .026), repeated chair rise (0.13 s/year, p = .020) and SPPB (-0.11 points/year, p = .002). OPEL women had slower decline on chair rise and SPPB scores compared to OPUS women, although OPEL men had slower decline on unipedal stance compared to OPUS men. Our findings provide evidence that variation in late-life decline in physical function is associated with familial longevity, and may vary for men and women. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Abdominally implanted transmitters with percutaneous antennas affect the dive performance of Common Eiders

USGS Publications Warehouse

Powell, Abby N.; Latty, Christopher J.; Hollmén, Tuula E.; Petersen, Margaret R.; Andrews, Russel D.

2010-01-01

Implanted transmitters have become an important tool for studying the ecology of sea ducks, but their effects remain largely undocumented. To address this, we assessed how abdominally implanted transmitters with percutaneous antennas affect the vertical dive speeds, stroke frequencies, bottom time, and dive duration of captive Common Eiders (Somateria mollissima). To establish baselines, we recorded video of six birds diving 4.9 m prior to surgery, implanted them with 38- to 47-g platform transmitter terminals, and then recorded their diving for 3.5 months after surgery to determine effects. Descent speeds were 16–25% slower and ascent speeds were 17–44% slower after surgery, and both remained below baseline at the end of the study. Dive durations were longer than baseline until day 22. On most days between 15 and 107 days after surgery, foot-stroke frequencies of birds foraging on the bottom were slower. Foot- and wing-stroke frequencies during descent and bottom time did not differ across the time series. If birds that rely on benthic invertebrates for sustenance dive slower and stay submerged longer after being implanted with a satellite transmitter, their foraging energetics may be affected. Researchers considering use of implanted transmitters with percutaneous antennas should be mindful of these effects and the possibility of concomitant alterations in diving behavior, foraging success, and migratory behavior compared to those of unmarked conspecifics.

Retardation of ice crystallization by short peptides

NASA Astrophysics Data System (ADS)

Kim, Jun Soo; Yethiraj, Arun

2009-03-01

The effect of short peptides on the growth of ice crystals is studied using molecular dynamics simulations. The simulations focus on two sequences (Gly-Pro-Ala-Gly and Gly-Gly-Ala-Gly) that are found in collagen hydrolysate, a substance that is known to retard crystal growth. In the absence of peptides, the growth of ice crystal in the solution with the ice/water interface is observed in at a rate comparable to the experimental data. When peptides are present in the liquid phase, the crystal growth is retarded to a significant extent compared to the pure water. It is found that Gly-Pro-Ala-Gly is more effective (crystallization is up to 5 times slower than in its absence) than Gly-Gly-Ala-Gly (up to 3 times slower) implying that the role of the proline residue is important. The mechanism can be understood in the nature of binding of the peptides to the growing crystal.

CLVTOPS Liftoff and Separation Analysis Validation Using Ares I-X Flight Data

NASA Technical Reports Server (NTRS)

Burger, Ben; Schwarz, Kristina; Kim, Young

2011-01-01

CLVTOPS is a multi-body time domain flight dynamics simulation tool developed by NASA s Marshall Space Flight Center (MSFC) for a space launch vehicle and is based on the TREETOPS simulation tool. CLVTOPS is currently used to simulate the flight dynamics and separation/jettison events of the Ares I launch vehicle including liftoff and staging separation. In order for CLVTOPS to become an accredited tool, validation against other independent simulations and real world data is needed. The launch of the Ares I-X vehicle (first Ares I test flight) on October 28, 2009 presented a great opportunity to provide validation evidence for CLVTOPS. In order to simulate the Ares I-X flight, specific models were implemented into CLVTOPS. These models include the flight day environment, reconstructed thrust, reconstructed mass properties, aerodynamics, and the Ares I-X guidance, navigation and control models. The resulting simulation output was compared to Ares I-X flight data. During the liftoff region of flight, trajectory states from the simulation and flight data were compared. The CLVTOPS results were used to make a semi-transparent animation of the vehicle that was overlaid directly on top of the flight video to provide a qualitative measure of the agreement between the simulation and the actual flight. During ascent, the trajectory states of the vehicle were compared with flight data. For the stage separation event, the trajectory states of the two stages were compared to available flight data. Since no quantitative rotational state data for the upper stage was available, the CLVTOPS results were used to make an animation of the two stages to show a side-by-side comparison with flight video. All of the comparisons between CLVTOPS and the flight data show good agreement. This paper documents comparisons between CLVTOPS and Ares I-X flight data which serve as validation evidence for the eventual accreditation of CLVTOPS.

KSC-2009-4407

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. – Space shuttle Discovery is silhouetted against the dawn sky as it rolls out to Launch Pad 39A at NASA's Kennedy Space Center in Florida. First motion out of the Vehicle Assembly Building was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. The 3.4-mile journey was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Dimitri Gerondidakis

KSC-2009-4412

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. –At NASA's Kennedy Space Center in Florida, a worker checks the tread on the crawler-transporter as it carries space shuttle Endeavour to Launch Pad 39A. The 3.4-mile journey was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. First motion out of the Vehicle Assembly Building was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Dimitri Gerondidakis

KSC-2009-4409

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. – The morning sun highlights the back of space shuttle Discovery as it makes its way to Launch Pad 39A at NASA's Kennedy Space Center in Florida. The 3.4-mile journey was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. First motion out of the Vehicle Assembly Building was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Dimitri Gerondidakis

KSC-2009-4411

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. – At NASA's Kennedy Space Center in Florida, a worker walks alongside the crawler-transporter as it carries space shuttle Endeavour to Launch Pad 39A. The 3.4-mile journey was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. First motion out of the Vehicle Assembly Building was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Dimitri Gerondidakis

KSC-2009-4406

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. – Space shuttle Discovery is silhouetted against the dawn sky as it rolls out to Launch Pad 39A at NASA's Kennedy Space Center in Florida. First motion out of the Vehicle Assembly Building was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. The 3.4-mile journey was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Dimitri Gerondidakis

Haste Makes Waste but Condition Matters: Molt Rate–Feather Quality Trade-Off in a Sedentary Songbird

PubMed Central

Vágási, Csongor I.; Pap, Péter L.; Vincze, Orsolya; Benkő, Zoltán; Marton, Attila; Barta, Zoltán

2012-01-01

Background The trade-off between current and residual reproductive values is central to life history theory, although the possible mechanisms underlying this trade-off are largely unknown. The ‘molt constraint’ hypothesis suggests that molt and plumage functionality are compromised by the preceding breeding event, yet this candidate mechanism remains insufficiently explored. Methodology/Principal Findings The seasonal change in photoperiod was manipulated to accelerate the molt rate. This treatment simulates the case of naturally late-breeding birds. House sparrows Passer domesticus experiencing accelerated molt developed shorter flight feathers with more fault bars and body feathers with supposedly lower insulation capacity (i.e. shorter, smaller, with a higher barbule density and fewer plumulaceous barbs). However, the wing, tail and primary feather lengths were shorter in fast-molting birds if they had an inferior body condition, which has been largely overlooked in previous studies. The rachis width of flight feathers was not affected by the treatment, but it was still condition-dependent. Conclusions/Significance This study shows that sedentary birds might face evolutionary costs because of the molt rate–feather quality conflict. This is the first study to experimentally demonstrate that (1) molt rate affects several aspects of body feathers as well as flight feathers and (2) the costly effects of rapid molt are condition-specific. We conclude that molt rate and its association with feather quality might be a major mediator of life history trade-offs. Our findings also suggest a novel advantage of early breeding, i.e. the facilitation of slower molt and the condition-dependent regulation of feather growth. PMID:22808221

Growth rate effects on the formation of dislocation loops around deep helium bubbles in Tungsten

DOE PAGES

Sandoval, Luis; Perez, Danny; Uberuaga, Blas P.; ...

2016-11-15

Here, the growth process of spherical helium bubbles located 6 nm below a (100) surface is studied using molecular dynamics and parallel replica dynamics simulations, over growth rates from 10 6 to 10 12 helium atoms per second. Slower growth rates lead to a release of pressure and lower helium content as compared with fast growth cases. In addition, at slower growth rates, helium bubbles are not decorated by multiple dislocation loops, as these tend to merge or emit given sufficient time. At faster rates, dislocation loops nucleate faster than they can emit, leading to a more complicated dislocation structuremore » around the bubble.« less

Metabolomics Characterization of U.S. and Japanese F-15 and C-130 Flight Line Crews Exposed to Jet Fuel Volatile Organic Compounds and Aerosols

DTIC Science & Technology

2014-09-30

resulted in the identification of metabolite patterns indicative of flight line exposure when compared to non -flight line control subjects...virtually non -invasive sample collection, minimal sample processing, robust and stable analytical platform, with excellent analytical and biological...identification of metabolite patterns indicative of flight line exposure when compared to non -flight line control subjects. Regardless of fuel (JP-4 or

A Preliminary Flight Investigation of Formation Flight for Drag Reduction on the C-17 Aircraft

NASA Technical Reports Server (NTRS)

Pahle, Joe; Berger, Dave; Venti, Michael W.; Faber, James J.; Duggan, Chris; Cardinal, Kyle

2012-01-01

Many theoretical and experimental studies have shown that aircraft flying in formation could experience significant reductions in fuel use compared to solo flight. To date, formation flight for aerodynamic benefit has not been thoroughly explored in flight for large transport-class vehicles. This paper summarizes flight data gathered during several two ship, C-17 formation flights at a single flight condition of 275 knots, at 25,000 ft MSL. Stabilized test points were flown with the trail aircraft at 1,000 and 3,000 ft aft of the lead aircraft at selected crosstrack and vertical offset locations within the estimated area of influence of the vortex generated by the lead aircraft. Flight data recorded at test points within the vortex from the lead aircraft are compared to data recorded at tare flight test points outside of the influence of the vortex. Since drag was not measured directly, reductions in fuel flow and thrust for level flight are used as a proxy for drag reduction. Estimated thrust and measured fuel flow reductions were documented at several trail test point locations within the area of influence of the leads vortex. The maximum average fuel flow reduction was approximately 7-8%, compared to the tare points flown before and after the test points. Although incomplete, the data suggests that regions with fuel flow and thrust reduction greater than 10% compared to the tare test points exist within the vortex area of influence.

Visual cues to geographical orientation during low-level flight

NASA Technical Reports Server (NTRS)

Battiste, Vernol; Delzell, Suzanne

1991-01-01

A field study of an operational Emergency Medical Service (EMS) unit was conducted to investigate the relationships among geographical orientation, pilot decision making, and workload in EMS flights. The map data collected during this study were compared to protocols gathered in the laboratory, where pilots viewed a simulated flight over different types of unfamiliar terrain and verbally identified the features utilized to maintain geographical orientation. The EMS pilot's questionnaire data were compared with data from non-EMS helicopter pilots with comparable flight experience.

Binocular Interactions Underlying the Classic Optomotor Responses of Flying Flies

PubMed Central

Duistermars, Brian J.; Care, Rachel A.; Frye, Mark A.

2012-01-01

In response to imposed course deviations, the optomotor reactions of animals reduce motion blur and facilitate the maintenance of stable body posture. In flies, many anatomical and electrophysiological studies suggest that disparate motion cues stimulating the left and right eyes are not processed in isolation but rather are integrated in the brain to produce a cohesive panoramic percept. To investigate the strength of such inter-ocular interactions and their role in compensatory sensory–motor transformations, we utilize a virtual reality flight simulator to record wing and head optomotor reactions by tethered flying flies in response to imposed binocular rotation and monocular front-to-back and back-to-front motion. Within a narrow range of stimulus parameters that generates large contrast insensitive optomotor responses to binocular rotation, we find that responses to monocular front-to-back motion are larger than those to panoramic rotation, but are contrast sensitive. Conversely, responses to monocular back-to-front motion are slower than those to rotation and peak at the lowest tested contrast. Together our results suggest that optomotor responses to binocular rotation result from the influence of non-additive contralateral inhibitory as well as excitatory circuit interactions that serve to confer contrast insensitivity to flight behaviors influenced by rotatory optic flow. PMID:22375108

Graphene: corrosion-inhibiting coating.

PubMed

Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R; Jennings, G Kane; Rogers, Bridget R; Bolotin, Kirill I

2012-02-28

We report the use of atomically thin layers of graphene as a protective coating that inhibits corrosion of underlying metals. Here, we employ electrochemical methods to study the corrosion inhibition of copper and nickel by either growing graphene on these metals, or by mechanically transferring multilayer graphene onto them. Cyclic voltammetry measurements reveal that the graphene coating effectively suppresses metal oxidation and oxygen reduction. Electrochemical impedance spectroscopy measurements suggest that while graphene itself is not damaged, the metal under it is corroded at cracks in the graphene film. Finally, we use Tafel analysis to quantify the corrosion rates of samples with and without graphene coatings. These results indicate that copper films coated with graphene grown via chemical vapor deposition are corroded 7 times slower in an aerated Na(2)SO(4) solution as compared to the corrosion rate of bare copper. Tafel analysis reveals that nickel with a multilayer graphene film grown on it corrodes 20 times slower while nickel surfaces coated with four layers of mechanically transferred graphene corrode 4 times slower than bare nickel. These findings establish graphene as the thinnest known corrosion-protecting coating.

Airborne measurements and emission estimates of greenhouse gases and other trace constituents from the 2013 California Yosemite Rim wildfire

NASA Astrophysics Data System (ADS)

Yates, E. L.; Iraci, L. T.; Singh, H. B.; Tanaka, T.; Roby, M. C.; Hamill, P.; Clements, C. B.; Lareau, N.; Contezac, J.; Blake, D. R.; Simpson, I. J.; Wisthaler, A.; Mikoviny, T.; Diskin, G. S.; Beyersdorf, A. J.; Choi, Y.; Ryerson, T. B.; Jimenez, J. L.; Campuzano-Jost, P.; Loewenstein, M.; Gore, W.

2016-02-01

This paper presents airborne measurements of multiple atmospheric trace constituents including greenhouse gases (such as CO2, CH4, O3) and biomass burning tracers (such as CO, CH3CN) downwind of an exceptionally large wildfire. In summer 2013, the Rim wildfire, ignited just west of the Yosemite National Park, California, and burned over 250,000 acres of the forest during the 2-month period (17 August to 24 October) before it was extinguished. The Rim wildfire plume was intercepted by flights carried out by the NASA Ames Alpha Jet Atmospheric eXperiment (AJAX) on 29 August and the NASA DC-8, as part of SEAC4RS (Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys), on 26 and 27 August during its intense, primary burning period. AJAX revisited the wildfire on 10 September when the conditions were increasingly smoldering, with slower growth. The more extensive payload of the DC-8 helped to bridge key measurements that were not available as part of AJAX (e. g. CO). Data analyses are presented in terms of emission ratios (ER), emission factors (EF) and combustion efficiency and are compared with previous wildfire studies. ERs were 8.0 ppb CH4 (ppm CO2)-1 on 26 August, 6.5 ppb CH4 (ppm CO2)-1 on 29 August and 18.3 ppb CH4 (ppm CO2)-1 on 10 September 2013. The increase in CH4 ER from 6.5 to 8.0 ppb CH4 (ppm CO2)-1 during the primary burning period to 18.3 ppb CH4 (ppm CO2)-1 during the fire's slower growth period likely indicates enhanced CH4 emissions from increased smoldering combustion relative to flaming combustion. Given the magnitude of the Rim wildfire, the impacts it had on regional air quality and the limited sampling of wildfire emissions in the western United States to date, this study provides a valuable dataset to support forestry and regional air quality management, including observations of ERs of a wide number of species from the Rim wildfire.

Airborne Measurements and Emission Estimates of Greenhouse Gases and Other Trace Constituents From the 2013 California Yosemite Rim Wildfire

NASA Technical Reports Server (NTRS)

Yates, E. L.; Iraci, L. T.; Singh, H. B.; Tanaka, T.; Roby, M. C.; Hamill, P.; Clements, C. B.; Lareau, N.; Contezac, J.; Blake, D. R.;

Optimal Aircraft Control Upset Recovery With and Without Component Failures

NASA Technical Reports Server (NTRS)

Sparks, Dean W.; Moerder, Daniel D.

2002-01-01

This paper treats the problem of recovering sustainable nondescending (safe) flight in a transport aircraft after one or more of its control effectors fail. Such recovery can be a challenging goal for many transport aircraft currently in the operational fleet for two reasons. First, they have very little redundancy in their means of generating control forces and moments. These aircraft have, as primary control surfaces, a single rudder and pairwise elevators and aileron/spoiler units that provide yaw, pitch, and roll moments with sufficient bandwidth to be used in stabilizing and maneuvering the airframe. Beyond this, throttling the engines can provide additional moments, but on a much slower time scale. Other aerodynamic surfaces, such as leading and trailing edge flaps, are only intended to be placed in a position and left, and are, hence, very slow-moving. Because of this, loss of a primary control surface strongly degrades the controllability of the vehicle, particularly when the failed effector becomes stuck in a non-neutral position where it exerts a disturbance moment that must be countered by the remaining operating effectors. The second challenge in recovering safe flight is that these vehicles are not agile, nor can they tolerate large accelerations. This is of special importance when, at the outset of the recovery maneuver, the aircraft is flying toward the ground, as is frequently the case when there are major control hardware failures. Recovery of safe flight is examined in this paper in the context of trajectory optimization. For a particular transport aircraft, and a failure scenario inspired by an historical air disaster, recovery scenarios are calculated with and without control surface failures, to bring the aircraft to safe flight from the adverse flight condition that it had assumed, apparently as a result of contact with a vortex from a larger aircraft's wake. An effort has been made to represent relevant airframe dynamics, acceleration limits, and actuator limits faithfully, since these contribute to the lack of agility and control power that plays an important role in defining what can be achieved with the vehicle when it is in extremis.

Performance of two MALDI-TOF MS systems for the identification of yeasts isolated from bloodstream infections and cerebrospinal fluids using a time-saving direct transfer protocol.

PubMed

Hamprecht, Axel; Christ, Sara; Oestreicher, Tanja; Plum, Georg; Kempf, Volkhard A J; Göttig, Stephan

2014-04-01

The rapid and correct identification of pathogens is of paramount importance for the treatment of patients with invasive infections. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) can speed up the identification of bacteria and fungi and has quickly been embraced by medical microbiology laboratories worldwide. Different MALDI-TOF systems have been compared in studies focussing on identification rates of different pathogens. Another aspect that has not been systematically assessed is the performance in daily routine and handling, which is important especially for microbiology routine laboratories. We compared two widespread commercial systems, Microflex LT Biotyper (Bruker) and VitekMS (bioMérieux), for the identification of 210 relevant clinical yeasts under routine conditions, using a time-saving direct transfer protocol. We assessed the need for an additional extraction step, the threshold for species identification and the duration of measurements with the two systems. The tested yeasts included 34 Candida albicans isolates, 144 non-albicans Candida spp. and 32 yeasts of different genera. The results of the two MS systems were compared with that of biochemical identification and, in case of discrepancies, DNA sequencing of the internal transcribed spacer or the large subunit of ribosomal DNA. Both systems correctly identified 96.2 % of isolates [202/210, non-significant (n.s.)]. Misidentifications were observed for VitekMS only (n = 5, no major errors, n.s.). VitekMS was the slower system (19.8 vs. 8.0 min for 10 samples, p = 0.002) but had the advantage of a more effective direct transfer protocol with less need for an additional extraction step.

Slow but not low: genomic comparisons reveal slower evolutionary rate and higher dN/dS in conifers compared to angiosperms

PubMed Central

2012-01-01

Background Comparative genomics can inform us about the processes of mutation and selection across diverse taxa. Among seed plants, gymnosperms have been lacking in genomic comparisons. Recent EST and full-length cDNA collections for two conifers, Sitka spruce (Picea sitchensis) and loblolly pine (Pinus taeda), together with full genome sequences for two angiosperms, Arabidopsis thaliana and poplar (Populus trichocarpa), offer an opportunity to infer the evolutionary processes underlying thousands of orthologous protein-coding genes in gymnosperms compared with an angiosperm orthologue set. Results Based upon pairwise comparisons of 3,723 spruce and pine orthologues, we found an average synonymous genetic distance (dS) of 0.191, and an average dN/dS ratio of 0.314. Using a fossil-established divergence time of 140 million years between spruce and pine, we extrapolated a nucleotide substitution rate of 0.68 × 10-9 synonymous substitutions per site per year. When compared to angiosperms, this indicates a dramatically slower rate of nucleotide substitution rates in conifers: on average 15-fold. Coincidentally, we found a three-fold higher dN/dS for the spruce-pine lineage compared to the poplar-Arabidopsis lineage. This joint occurrence of a slower evolutionary rate in conifers with higher dN/dS, and possibly positive selection, showcases the uniqueness of conifer genome evolution. Conclusions Our results are in line with documented reduced nucleotide diversity, conservative genome evolution and low rates of diversification in conifers on the one hand and numerous examples of local adaptation in conifers on the other hand. We propose that reduced levels of nucleotide mutation in large and long-lived conifer trees, coupled with large effective population size, were the main factors leading to slow substitution rates but retention of beneficial mutations. PMID:22264329

Aeroelastic Deformation: Adaptation of Wind Tunnel Measurement Concepts to Full-Scale Vehicle Flight Testing

NASA Technical Reports Server (NTRS)

Burner, Alpheus W.; Lokos, William A.; Barrows, Danny A.

2005-01-01

The adaptation of a proven wind tunnel test technique, known as Videogrammetry, to flight testing of full-scale vehicles is presented. A description is presented of the technique used at NASA's Dryden Flight Research Center for the measurement of the change in wing twist and deflection of an F/A-18 research aircraft as a function of both time and aerodynamic load. Requirements for in-flight measurements are compared and contrasted with those for wind tunnel testing. The methodology for the flight-testing technique and differences compared to wind tunnel testing are given. Measurement and operational comparisons to an older in-flight system known as the Flight Deflection Measurement System (FDMS) are presented.

Shift schedule, work-family relationships, marital communication, job satisfaction and health among transport service shift workers.

PubMed

Iskra-Golec, Irena; Smith, Lawrence; Wilczek-Rużyczka, Ewa; Siemiginowska, Patrycja; Wątroba, Joanna

2017-02-21

Existing research has documented that shiftwork consequences may depend on the shift system parameters. Fast rotating systems (1-3 shifts of the same kind in a row) and day work have been found to be less disruptive biologically and socially than slower rotating systems and afternoon and night work. The aim of this study was to compare day workers and shift workers of different systems in terms of rotation speed and shifts worked with regard to work-family and family-work positive and negative spillover, marital communication style, job satisfaction and health. Employees (N = 168) of the maintenance workshops of transportation service working different shift systems (day shift, weekly rotating 2 and 3‑shift system, and fast rotating 3-shift system) participated in the study. They completed the Work- Family Spillover Questionnaire, Marital Communication Questionnaire, Minnesota Job Satisfaction Questionnaire and the Physical Health Questionnaire (a part of the Standard Shiftwork Index). The workers of quicker rotating 3-shift systems reported significantly higher scores of family-to-work facilitation (F(3, 165) = 4.175, p = 0.007) and a higher level of constructive style of marital communication (Engagement F(3, 165) = 2.761, p = 0.044) than the workers of slower rotating 2-shift systems. There were no differences between the groups of workers with regard to health and job satisfaction. A higher level of work-family facilitation and a more constructive style of marital communication were found among the workers of faster rotating 3-shift system when compared to the workers of a slower rotating 2-shift system (afternoon, night). This may indicate that the fast rotating shift system in contrary to the slower rotating one is more friendly for the work and family domains and for the relationship between them. Int J Occup Med Environ Health 2017;30(1):121-131. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Information Display System for Atypical Flight Phase

NASA Technical Reports Server (NTRS)

Statler, Irving C. (Inventor); Ferryman, Thomas A. (Inventor); Amidan, Brett G. (Inventor); Whitney, Paul D. (Inventor); White, Amanda M. (Inventor); Willse, Alan R. (Inventor); Cooley, Scott K. (Inventor); Jay, Joseph Griffith (Inventor); Lawrence, Robert E. (Inventor); Mosbrucker, Chris J. (Inventor);

XB-70A #1 liftoff with TB-58A chase aircraft

NASA Technical Reports Server (NTRS)

1960-01-01

This photo shows XB-70A #1 taking off on a research flight, escorted by a TB-58 chase plane. The TB-58 (a prototype B-58 modified as a trainer) had a dash speed of Mach 2. This allowed it to stay close to the XB-70 as it conducted its research maneuvers. When the XB-70 was flying at or near Mach 3, the slower TB-58 could often keep up with it by flying lower and cutting inside the turns in the XB-70's flight path when these occurred. The XB-70 was the world's largest experimental aircraft. It was capable of flight at speeds of three times the speed of sound (roughly 2,000 miles per hour) at altitudes of 70,000 feet. It was used to collect in-flight information for use in the design of future supersonic aircraft, military and civilian. The major objectives of the XB-70 flight research program were to study the airplane's stability and handling characteristics, to evaluate its response to atmospheric turbulence, and to determine the aerodynamic and propulsion performance. In addition there were secondary objectives to measure the noise and friction associated with airflow over the airplane and to determine the levels and extent of the engine noise during takeoff, landing, and ground operations. The XB-70 was about 186 feet long, 33 feet high, with a wingspan of 105 feet. Originally conceived as an advanced bomber for the United States Air Force, the XB-70 was limited to production of two aircraft when it was decided to limit the aircraft's mission to flight research. The first flight of the XB-70 was made on Sept. 21, 1964. The number two XB-70 was destroyed in a mid-air collision on June 8, 1966. Program management of the NASA-USAF research effort was assigned to NASA in March 1967. The final flight was flown on Feb. 4, 1969. Designed by North American Aviation (later North American Rockwell and still later, a division of Boeing) the XB-70 had a long fuselage with a canard or horizontal stabilizer mounted just behind the crew compartment. It had a sharply swept 65.6-percent delta wing. The outer portion of the wing could be folded down in flight to provide greater lateral-directional stability. The airplane had two windshields. A moveable outer windshield was raised for high-speed flight to reduce drag and lowered for greater visibility during takeoff and landing. The forward fuselage was constructed of riveted titanium frames and skin. The remainder of the airplane was constructed almost entirely of stainless steel. The skin was a brazed stainless-steel honeycomb material. Six General Electric YJ93-3 turbojet engines, each in the 30,000-pound-thrust class, powered the XB-70. Internal geometry of the inlets was controllable to maintain the most efficient airflow to the engines.

Pre- and post-flight-test models versus measured skyship-500 control responses

NASA Technical Reports Server (NTRS)

Jex, Henry R.; Magdaleno, Raymond E.; Gelhausen, Paul; Tischler, Mark B.

1987-01-01

The dynamical equations-of-motion (EOM) for cruising airships require nonconventional terms to account for buoyancy and apparent-mass-effects, but systematic validation of these equations against flight data is not available. Using a candidate set of EOM, three comparisons are made with carefully-measured describing functions derived from frequency-sweep flight tests on the Skyship-500 airship. The first compares the pre-flight predictions to the data; the second compares the 'best-fit' equations to data at each of two airspeeds and the third compared the ability to extrapolate from one condition to another via airship-specific scaling laws. Two transient responses are also compared. The generally good results demonstrate that fairly simple, perturbation equation models are adequate for many types of flight-control analysis and flying quality evaluations of cruising airships.

ACUTE METHANOL TOXICITY IN MINIPIGS

EPA Science Inventory

The pig hos been proposed as a potential animal model for methanol-induced neuro-ocular toxicosis in humans because of its reported low liver tetrahydro folate levels and therefore, slower formate metabolism as compared to humans. o determine the validity of the animal model, min...

Comparative analysis of operational forecasts versus actual weather conditions in airline flight planning, volume 2

NASA Technical Reports Server (NTRS)

Keitz, J. F.

1982-01-01

The impact of more timely and accurate weather data on airline flight planning with the emphasis on fuel savings is studied. This volume of the report discusses the results of Task 2 of the four major tasks included in the study. Task 2 compares various catagories of flight plans and flight tracking data produced by a simulation system developed for the Federal Aviation Administrations by SRI International. (Flight tracking data simulate actual flight tracks of all aircraft operating at a given time and provide for rerouting of flights as necessary to resolve traffic conflicts.) The comparisons of flight plans on the forecast to flight plans on the verifying analysis confirm Task 1 findings that wind speeds are generally underestimated. Comparisons involving flight tracking data indicate that actual fuel burn is always higher than planned, in either direction, and even when the same weather data set is used. Since the flight tracking model output results in more diversions than is known to be the case, it was concluded that there is an error in the flight tracking algorithm.

The self-reported health of U.S. flight attendants compared to the general population

PubMed Central

2014-01-01

Background Few studies have examined the broad health effects of occupational exposures in flight attendants apart from disease-specific morbidity and mortality studies. We describe the health status of flight attendants and compare it to the U.S. population. In addition, we explore whether the prevalence of major health conditions in flight attendants is associated with length of exposure to the aircraft environment using job tenure as a proxy. Methods We surveyed flight attendants from two domestic U.S. airlines in 2007 and compared the prevalence of their health conditions to contemporaneous cohorts in the National Health and Nutrition Survey (NHANES), 2005-2006 and 2007-2008. We weighted the prevalence of flight attendant conditions to match the age distribution in the NHANES and compared the two populations stratified by gender using the Standardized Prevalence Ratio (SPR). For leading health conditions in flight attendants, we analyzed the association between job tenure and health outcomes in logistic regression models. Results Compared to the NHANES population (n =5,713), flight attendants (n = 4,011) had about a 3-fold increase in the age-adjusted prevalence of chronic bronchitis despite considerably lower levels of smoking. In addition, the prevalence of cardiac disease in female flight attendants was 3.5 times greater than the general population while their prevalence of hypertension and being overweight was significantly lower. Flight attendants reported 2 to 5.7 times more sleep disorders, depression, and fatigue, than the general population. Female flight attendants reported 34% more reproductive cancers. Health conditions that increased with longer job tenure as a flight attendant were chronic bronchitis, heart disease in females, skin cancer, hearing loss, depression and anxiety, even after adjusting for age, gender, body mass index (BMI), education, and smoking. Conclusions This study found higher rates of specific diseases in flight attendants than the general population. Longer tenure appears to explain some of the higher disease prevalence. Conclusions are limited by the cross-sectional design and recall bias. Further study is needed to determine the source of risk and to elucidate specific exposure-disease relationships over time. PMID:24612632

Effect of magnetically simulated zero-gravity and enhanced gravity on the walk of the common fruitfly†

PubMed Central

Hill, Richard J. A.; Larkin, Oliver J.; Dijkstra, Camelia E.; Manzano, Ana I.; de Juan, Emilio; Davey, Michael R.; Anthony, Paul; Eaves, Laurence; Medina, F. Javier; Marco, Roberto; Herranz, Raul

2012-01-01

Understanding the effects of gravity on biological organisms is vital to the success of future space missions. Previous studies in Earth orbit have shown that the common fruitfly (Drosophila melanogaster) walks more quickly and more frequently in microgravity, compared with its motion on Earth. However, flight preparation procedures and forces endured on launch made it difficult to implement on the Earth's surface a control that exposed flies to the same sequence of major physical and environmental changes. To address the uncertainties concerning these behavioural anomalies, we have studied the walking paths of D. melanogaster in a pseudo-weightless environment (0g*) in our Earth-based laboratory. We used a strong magnetic field, produced by a superconducting solenoid, to induce a diamagnetic force on the flies that balanced the force of gravity. Simultaneously, two other groups of flies were exposed to a pseudo-hypergravity environment (2g*) and a normal gravity environment (1g*) within the spatially varying field. The flies had a larger mean speed in 0g* than in 1g*, and smaller in 2g*. The mean square distance travelled by the flies grew more rapidly with time in 0g* than in 1g*, and slower in 2g*. We observed no other clear effects of the magnetic field, up to 16.5 T, on the walks of the flies. We compare the effect of diamagnetically simulated weightlessness with that of weightlessness in an orbiting spacecraft, and identify the cause of the anomalous behaviour as the altered effective gravity. PMID:22219396

Effect of magnetically simulated zero-gravity and enhanced gravity on the walk of the common fruitfly.

PubMed

Hill, Richard J A; Larkin, Oliver J; Dijkstra, Camelia E; Manzano, Ana I; de Juan, Emilio; Davey, Michael R; Anthony, Paul; Eaves, Laurence; Medina, F Javier; Marco, Roberto; Herranz, Raul

2012-07-07

Understanding the effects of gravity on biological organisms is vital to the success of future space missions. Previous studies in Earth orbit have shown that the common fruitfly (Drosophila melanogaster) walks more quickly and more frequently in microgravity, compared with its motion on Earth. However, flight preparation procedures and forces endured on launch made it difficult to implement on the Earth's surface a control that exposed flies to the same sequence of major physical and environmental changes. To address the uncertainties concerning these behavioural anomalies, we have studied the walking paths of D. melanogaster in a pseudo-weightless environment (0g*) in our Earth-based laboratory. We used a strong magnetic field, produced by a superconducting solenoid, to induce a diamagnetic force on the flies that balanced the force of gravity. Simultaneously, two other groups of flies were exposed to a pseudo-hypergravity environment (2g*) and a normal gravity environment (1g*) within the spatially varying field. The flies had a larger mean speed in 0g* than in 1g*, and smaller in 2g*. The mean square distance travelled by the flies grew more rapidly with time in 0g* than in 1g*, and slower in 2g*. We observed no other clear effects of the magnetic field, up to 16.5 T, on the walks of the flies. We compare the effect of diamagnetically simulated weightlessness with that of weightlessness in an orbiting spacecraft, and identify the cause of the anomalous behaviour as the altered effective gravity.

Comparison of a Fixed-Wing and Multi-Rotor Uav for Environmental Mapping Applications: a Case Study

NASA Astrophysics Data System (ADS)

Boon, M. A.; Drijfhout, A. P.; Tesfamichael, S.

2017-08-01

The advent and evolution of Unmanned Aerial Vehicles (UAVs) and photogrammetric techniques has provided the possibility for on-demand high-resolution environmental mapping. Orthoimages and three dimensional products such as Digital Surface Models (DSMs) are derived from the UAV imagery which is amongst the most important spatial information tools for environmental planning. The two main types of UAVs in the commercial market are fixed-wing and multi-rotor. Both have their advantages and disadvantages including their suitability for certain applications. Fixed-wing UAVs normally have longer flight endurance capabilities while multi-rotors can provide for stable image capturing and easy vertical take-off and landing. Therefore, the objective of this study is to assess the performance of a fixed-wing versus a multi-rotor UAV for environmental mapping applications by conducting a specific case study. The aerial mapping of the Cors-Air model aircraft field which includes a wetland ecosystem was undertaken on the same day with a Skywalker fixed-wing UAV and a Raven X8 multi-rotor UAV equipped with similar sensor specifications (digital RGB camera) under the same weather conditions. We compared the derived datasets by applying the DTMs for basic environmental mapping purposes such as slope and contour mapping including utilising the orthoimages for identification of anthropogenic disturbances. The ground spatial resolution obtained was slightly higher for the multi-rotor probably due to a slower flight speed and more images. The results in terms of the overall precision of the data was noticeably less accurate for the fixed-wing. In contrast, orthoimages derived from the two systems showed small variations. The multi-rotor imagery provided better representation of vegetation although the fixed-wing data was sufficient for the identification of environmental factors such as anthropogenic disturbances. Differences were observed utilising the respective DTMs for the mapping of the wetland slope and contour mapping including the representation of hydrological features within the wetland. Factors such as cost, maintenance and flight time is in favour of the Skywalker fixed-wing. The multi-rotor on the other hand is more favourable in terms of data accuracy including for precision environmental planning purposes although the quality of the data of the fixed-wing is satisfactory for most environmental mapping applications.

Flight Technical Error Analysis of the SATS Higher Volume Operations Simulation and Flight Experiments

NASA Technical Reports Server (NTRS)

Williams, Daniel M.; Consiglio, Maria C.; Murdoch, Jennifer L.; Adams, Catherine H.

2005-01-01

This paper provides an analysis of Flight Technical Error (FTE) from recent SATS experiments, called the Higher Volume Operations (HVO) Simulation and Flight experiments, which NASA conducted to determine pilot acceptability of the HVO concept for normal operating conditions. Reported are FTE results from simulation and flight experiment data indicating the SATS HVO concept is viable and acceptable to low-time instrument rated pilots when compared with today s system (baseline). Described is the comparative FTE analysis of lateral, vertical, and airspeed deviations from the baseline and SATS HVO experimental flight procedures. Based on FTE analysis, all evaluation subjects, low-time instrument-rated pilots, flew the HVO procedures safely and proficiently in comparison to today s system. In all cases, the results of the flight experiment validated the results of the simulation experiment and confirm the utility of the simulation platform for comparative Human in the Loop (HITL) studies of SATS HVO and Baseline operations.

Aging near the wall in colloidal glasses

NASA Astrophysics Data System (ADS)

Cao, Cong; Huang, Xinru; Weeks, Eric

In a colloidal glass system, particles move slower as sample ages. In addition, their motions may be affected by their local structure, and this structure will be different near a wall. We examine how the aging process near a wall differs from that in the bulk of the sample. In particular, we use a confocal microscope to observe 3D motion in a bidisperse colloidal glass sample. We find that flat walls induce the particles to organize into layers. The aging process behaves differently near the boundary, especially within the first three layers. Particle motion near the wall is noticeably slower but also changes less dramatically with age. We compare and contrast aging seen in samples with flat and rough walls.

Preterm newborns show slower repair of oxidative damage and paternal smoking associated DNA damage.

PubMed

Vande Loock, Kim; Ciardelli, Roberta; Decordier, Ilse; Plas, Gina; Haumont, Dominique; Kirsch-Volders, Micheline

2012-09-01

Newborns have to cope with hypoxia during delivery and a sudden increase in oxygen at birth. Oxygen will partly be released as reactive oxygen species having the potential to cause damage to DNA and proteins. In utero, increase of most (non)-enzymatic antioxidants occurs during last weeks of gestation, making preterm neonates probably more sensitive to oxidative stress. Moreover, it has been hypothesized that oxidative stress might be the common etiological factor for certain neonatal diseases in preterm infants. The aim of this study was to assess background DNA damage; in vitro H(2)O(2) induced oxidative DNA damage and repair capacity (residual DNA damage) in peripheral blood mononucleated cells from 25 preterm newborns and their mothers. In addition, demographic data were taken into account and repair capacity of preterm was compared with full-term newborns. Multivariate linear regression analysis revealed that preterm infants from smoking fathers have higher background DNA damage levels than those from non-smoking fathers, emphasizing the risk of paternal smoking behaviour for the progeny. Significantly higher residual DNA damage found after 15-min repair in preterm children compared to their mothers and higher residual DNA damage after 2 h compared to full-term newborns suggest a slower DNA repair capacity in preterm children. In comparison with preterm infants born by caesarean delivery, preterm infants born by vaginal delivery do repair more slowly the in vitro induced oxidative DNA damage. Final impact of passive smoking and of the slower DNA repair activity of preterm infants need to be confirmed in a larger study population combining transgenerational genetic and/or epigenetic effects, antioxidant levels, genotypes, repair enzyme efficiency/levels and infant morbidity.

Interpretation of Overall Colonic Transit in Defecation Disorders in Males and Females

PubMed Central

Shin, Andrea; Camilleri, Michael; Nadeau, Ashley; Nullens, Sara; Rhee, Jong Chul; Jeong, In Du; Burton, Duane D.

2013-01-01

Background There is little information regarding gender-specific measurements of colonic transit and anorectal function in patients with defecation disorders (DD). Aim To compare overall colonic transit by gender in DD. Methods In 407 patients with constipation due to DD diagnosed by a single gastroenterologist (1994– 2012), DD was characterized by anorectal manometry, balloon expulsion test, and colonic transit by scintigraphy. The primary endpoint was overall colonic transit (geometric center, GC) at 24hours (GC24). Effects of gender in DD on colonic transit, and comparison with transit in 208 healthy controls were assessed by Mann-Whitney rank sum test. Secondary endpoints were maximum anal resting (ARP) and squeeze (ASP) pressures. We also tested association of the physiological endpoints among DD females by pregnancy history and among DD patients by colectomy history. Results The DD patients were 67 males (M) and 340 females (F). Significant differences by gender in DD patients were observed in GC24 (median: M: 2.2; F: 1.8; p=0.01), ARP (median: M: 87.8mmHg; F: 82.4mmHg; p=0.04), and ASP (median: M: 182.4mmHg; F: 128.7mmHg; p<0.001). GC24 was slower in DD compared to same gender healthy controls. GC24 did not differ among DD females by pregnancy history. Anorectal functions and upper GI transit did not differ among DD patients by colectomy history. Conclusions Patients with DD have slower colonic transit compared to gender-matched controls. Among DD patients, males have higher ARP and ASP, and females have slower colonic transit. Although the clinical significance of these differences may be unclear, findings suggest that interpretation of these tests in suspected DD should be based on same gender control data. PMID:23406422

Reversal learning in gonadectomized marmosets with and without hormone replacement: are males more sensitive to punishment?

PubMed

LaClair, Matthew; Lacreuse, Agnès

2016-05-01

This study examined sex differences in executive function in middle-aged gonadectomized marmosets (Callithrix jacchus) with or without hormonal replacement. We tested ten castrated male (mean age 5.5 years) marmosets treated with testosterone cypionate (T, n = 5) or vehicle (n = 5) on Reversal Learning, which contributes to cognitive flexibility, and the Delayed Response task, measuring working memory. Their performance was compared to that of 11 ovariectomized females (mean age = 3.7 years) treated with Silastic capsules filled with 17-β estradiol (E2, n = 6) or empty capsules (n = 5), previously tested on the same tasks (Lacreuse et al. in J Neuroendocrinol 26:296-309, 2014. doi: 10.1111/jne.12147). Behavioral observations were conducted daily. Females exhibited more locomotor behaviors than males. Males and females did not differ in the number of trials taken to reach criterion on the reversals, but males had significantly longer response latencies, regardless of hormone replacement. They also had a greater number of refusals than females. Additionally, both control and T-treated males, but not females, had slower responses on incorrect trials, suggesting that males were making errors due to distraction, lack of motivation or uncertainty. Furthermore, although both males and females had slower responding following an incorrect compared to a correct trial, the sex difference in response latencies was disproportionally large following an incorrect trial. No sex difference was found in the Delayed Response task. Overall, slower response latencies in males than females during Reversal Learning, especially during and following an incorrect trial, may reflect greater sensitivity to punishment (omission of reward) and greater performance monitoring in males, compared to females. Because these differences occurred in gonadectomized animals and regardless of hormone replacement, they may be organized early in life.

Aerodynamic Flight-Test Results for the Adaptive Compliant Trailing Edge

NASA Technical Reports Server (NTRS)

Cumming, Stephen B.; Smith, Mark S.; Ali, Aliyah N.; Bui, Trong T.; Ellsworth, Joel C.; Garcia, Christian A.

2016-01-01

The aerodynamic effects of compliant flaps installed onto a modified Gulfstream III airplane were investigated. Analyses were performed prior to flight to predict the aerodynamic effects of the flap installation. Flight tests were conducted to gather both structural and aerodynamic data. The airplane was instrumented to collect vehicle aerodynamic data and wing pressure data. A leading-edge stagnation detection system was also installed. The data from these flights were analyzed and compared with predictions. The predictive tools compared well with flight data for small flap deflections, but differences between predictions and flight estimates were greater at larger deflections. This paper describes the methods used to examine the aerodynamics data from the flight tests and provides a discussion of the flight-test results in the areas of vehicle aerodynamics, wing sectional pressure coefficient profiles, and air data.

Cruise noise of the SR-2 propeller model in a wind tunnel

NASA Technical Reports Server (NTRS)

Dittmar, James H.

1989-01-01

Noise data on the SR-2 model propeller were taken in the NASA Lewis Research Center 8- by 6-Foot Wind Tunnel. The maximum blade passing tone rises with increasing helical tip Mach number to a peak level at a helical tip Mach number of about 1.05; then it remains the same or decreases at higher helical tip Mach numbers. This behavior, which has been observed with other propeller models, points to the possibility of using higher propeller tip speeds to limit airplane cabin noise while maintaining high flight speed and efficiency. Noise comparisons of the straight-blade SR-2 propeller and the swept-blade SR-7A propeller showed that the tailored sweep of the SR-7A appears to be the cause of both lower peak noise levels and a slower noise increase with increasing helical tip Mach number.

Optimum take-off angle in the long jump.

PubMed

Linthorne, Nicholas P; Guzman, Maurice S; Bridgett, Lisa A

2005-07-01

In this study, we found that the optimum take-off angle for a long jumper may be predicted by combining the equation for the range of a projectile in free flight with the measured relations between take-off speed, take-off height and take-off angle for the athlete. The prediction method was evaluated using video measurements of three experienced male long jumpers who performed maximum-effort jumps over a wide range of take-off angles. To produce low take-off angles the athletes used a long and fast run-up, whereas higher take-off angles were produced using a progressively shorter and slower run-up. For all three athletes, the take-off speed decreased and the take-off height increased as the athlete jumped with a higher take-off angle. The calculated optimum take-off angles were in good agreement with the athletes' competition take-off angles.

Negative charge emission due to excimer laser bombardment of sodium trisilicate glass

NASA Astrophysics Data System (ADS)

Langford, S. C.; Jensen, L. C.; Dickinson, J. T.; Pederson, L. R.

1990-10-01

We describe measurements of negative charge emission accompanying irradiation of sodium trisilicate glass (Na2Oṡ3SiO2) with 248-nm excimer laser light at fluences on the order of 2 J/cm2 per pulse, i.e., at the threshold for ablative etching of the glass surface. The negative charge emission consists of a very prompt photoelectron burst coincident with the laser pulse, followed by a much slower plume of electrons and negative ions traveling with a high density cloud of positive ions, previously identified as primarily Na+. Using combinations of E and B fields in conjunction with time-of-flight methods, the negative ions were successfully separated from the plume and tentatively identified as O-, Si-, NaO-, and perhaps NaSi-. These negative species are probably formed by gas phase collisions in the near-surface region which result in electron attachment.

Response time effects of alerting tone and semantic context for synthesized voice cockpit warnings

NASA Technical Reports Server (NTRS)

Simpson, C. A.; Williams, D. H.

1980-01-01

Some handbooks and human factors design guides have recommended that a voice warning should be preceded by a tone to attract attention to the warning. As far as can be determined from a search of the literature, no experimental evidence supporting this exists. A fixed-base simulator flown by airline pilots was used to test the hypothesis that the total 'system-time' to respond to a synthesized voice cockpit warning would be longer when the message was preceded by a tone because the voice itself was expected to perform both the alerting and the information transfer functions. The simulation included realistic ATC radio voice communications, synthesized engine noise, cockpit conversation, and realistic flight routes. The effect of a tone before a voice warning was to lengthen response time; that is, responses were slower with an alerting tone. Lengthening the voice warning with another work, however, did not increase response time.

"Thunderstruck": Plasma-Polymer-Coated Porous Silicon Microparticles As a Controlled Drug Delivery System.

PubMed

McInnes, Steven J P; Michl, Thomas D; Delalat, Bahman; Al-Bataineh, Sameer A; Coad, Bryan R; Vasilev, Krasimir; Griesser, Hans J; Voelcker, Nicolas H

2016-02-01

Controlling the release kinetics from a drug carrier is crucial to maintain a drug's therapeutic window. We report the use of biodegradable porous silicon microparticles (pSi MPs) loaded with the anticancer drug camphothecin, followed by a plasma polymer overcoating using a loudspeaker plasma reactor. Homogenous "Teflon-like" coatings were achieved by tumbling the particles by playing AC/DC's song "Thunderstruck". The overcoating resulted in a markedly slower release of the cytotoxic drug, and this effect correlated positively with the plasma polymer coating times, ranging from 2-fold up to more than 100-fold. Ultimately, upon characterizing and verifying pSi MP production, loading, and coating with analytical methods such as time-of-flight secondary ion mass spectrometry, scanning electron microscopy, thermal gravimetry, water contact angle measurements, and fluorescence microscopy, human neuroblastoma cells were challenged with pSi MPs in an in vitro assay, revealing a significant time delay in cell death onset.

KSC-2009-4414

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. –Sitting on top of the mobile launcher platform and propelled by the crawler-transporter, space shuttle Discovery rolls up Launch Pad 39A at NASA's Kennedy Space Center in Florida after a nearly 12-hour journey from the Vehicle Assembly Building. First motion out of the VAB was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. The rollout was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Troy Cryder

KSC-2009-4415

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. –Sitting on top of the mobile launcher platform and propelled by the crawler-transporter, space shuttle Discovery rolls up Launch Pad 39A at NASA's Kennedy Space Center in Florida after a nearly 12-hour journey from the Vehicle Assembly Building. First motion out of the VAB was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. The rollout was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Troy Cryder

KSC-2009-4420

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. –Sitting on top of the mobile launcher platform and propelled by the crawler-transporter, space shuttle Discovery rolls onto Launch Pad 39A at NASA's Kennedy Space Center in Florida after a nearly 12-hour journey from the Vehicle Assembly Building. First motion out of the VAB was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. The rollout was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Troy Cryder

KSC-2009-4410

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. – Cast in shadow by the external fuel tank blocking the morning sun, space shuttle Discovery makes its way to Launch Pad 39A at NASA's Kennedy Space Center in Florida. The 3.4-mile journey was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. First motion out of the Vehicle Assembly Building was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Dimitri Gerondidakis

Cooling rate effects in sodium silicate glasses: Bridging the gap between molecular dynamics simulations and experiments

NASA Astrophysics Data System (ADS)

Li, Xin; Song, Weiying; Yang, Kai; Krishnan, N. M. Anoop; Wang, Bu; Smedskjaer, Morten M.; Mauro, John C.; Sant, Gaurav; Balonis, Magdalena; Bauchy, Mathieu

2017-08-01

Although molecular dynamics (MD) simulations are commonly used to predict the structure and properties of glasses, they are intrinsically limited to short time scales, necessitating the use of fast cooling rates. It is therefore challenging to compare results from MD simulations to experimental results for glasses cooled on typical laboratory time scales. Based on MD simulations of a sodium silicate glass with varying cooling rate (from 0.01 to 100 K/ps), here we show that thermal history primarily affects the medium-range order structure, while the short-range order is largely unaffected over the range of cooling rates simulated. This results in a decoupling between the enthalpy and volume relaxation functions, where the enthalpy quickly plateaus as the cooling rate decreases, whereas density exhibits a slower relaxation. Finally, we show that, using the proper extrapolation method, the outcomes of MD simulations can be meaningfully compared to experimental values when extrapolated to slower cooling rates.

Performance Lapses in Children with Attention-Deficit/Hyperactivity Disorder Contribute to Poor Reading Fluency

PubMed Central

Jacobson, Lisa A.; Ryan, Matthew; Denckla, Martha B.; Mostofsky, Stewart H.; Mahone, E. Mark

2013-01-01

Children with Attention-Deficit/Hyperactivity Disorder (ADHD) demonstrate increased response variability compared with controls, which is thought to be associated with deficits in attention regulation and response control that subsequently affect performance of more cognitively demanding tasks, such as reading. The present study examined response variability during a computerized simple reaction time (RT) task in 67 children. Ex-Gaussian analyses separated the response time distribution into normal (mu and sigma) and exponential (tau) components; the association of each with reading fluency was examined. Children with ADHD had significantly slower, more variable, and more skewed RTs compared with controls. After controlling for ADHD symptom severity, tau (but not mu or mean RT) was significantly associated with reduced reading fluency, but not with single word reading accuracy. These data support the growing evidence that RT variability, but not simply slower mean response speed, is the characteristic of youth with ADHD and that longer response time latencies (tau) may be implicated in the poorer academic performance associated with ADHD. PMID:23838684

Performance lapses in children with attention-deficit/hyperactivity disorder contribute to poor reading fluency.

PubMed

Jacobson, Lisa A; Ryan, Matthew; Denckla, Martha B; Mostofsky, Stewart H; Mahone, E Mark

2013-11-01

Children with Attention-Deficit/Hyperactivity Disorder (ADHD) demonstrate increased response variability compared with controls, which is thought to be associated with deficits in attention regulation and response control that subsequently affect performance of more cognitively demanding tasks, such as reading. The present study examined response variability during a computerized simple reaction time (RT) task in 67 children. Ex-Gaussian analyses separated the response time distribution into normal (mu and sigma) and exponential (tau) components; the association of each with reading fluency was examined. Children with ADHD had significantly slower, more variable, and more skewed RTs compared with controls. After controlling for ADHD symptom severity, tau (but not mu or mean RT) was significantly associated with reduced reading fluency, but not with single word reading accuracy. These data support the growing evidence that RT variability, but not simply slower mean response speed, is the characteristic of youth with ADHD and that longer response time latencies (tau) may be implicated in the poorer academic performance associated with ADHD.

Effects of spaceflight on the spermatogonial population of rat seminiferous epithelium

NASA Technical Reports Server (NTRS)

Sapp, Walter J.; Philpott, Delbert E.; Williams, Carol S.; Kato, Katharine; Stevenson, Joann; Vasquez, M.; Serova, L. V.

1990-01-01

Testes from rats flown on Cosmos 1887 were compared with vivarium control and synchronous control samples. The mean weights of flight testes, normalized for weight per 100 g, were 6.4 percent less when compared with the vivarium controls. Counts of spermatogonia from tissue sections (seminiferous tubules in maturation stage 6) from five animals in each group revealed 4 percent fewer spermatogonia in flight testes compared with synchronous controls and 11 percent fewer spermatogonia in flight samples compared with vivarium controls.

Potential effects of the United States-Mexico border fence on wildlife.

PubMed

Flesch, Aaron D; Epps, Clinton W; Cain, James W; Clark, Matt; Krausman, Paul R; Morgart, John R

2010-02-01

Security infrastructure along international boundaries threatens to degrade connectivity for wildlife. To explore potential effects of a fence under construction along the U.S.-Mexico border on wildlife, we assessed movement behavior of two species with different life histories whose regional persistence may depend on transboundary movements. We used radiotelemetry to assess how vegetation and landscape structure affect flight and natal dispersal behaviors of Ferruginous Pygmy-Owls (Glaucidium brasilianum), and satellite telemetry, gene-flow estimates, and least-cost path models to assess movement behavior and interpopulation connectivity of desert bighorn sheep (Ovis canadensis mexicana). Flight height of Pygmy-Owls averaged only 1.4 m (SE 0.1) above ground, and only 23% of flights exceeded 4 m. Juvenile Pygmy-Owls dispersed at slower speeds, changed direction more, and had lower colonization success in landscapes with larger vegetation openings or higher levels of disturbance (p < or = 0.047), which suggests large vegetation gaps coupled with tall fences may limit transboundary movements. Female bighorn sheep crossed valleys up to 4.9 km wide, and microsatellite analyses indicated relatively high levels of gene flow and migration (95% CI for F(ST)=0.010-0.115, Nm = 1.9-24.8, M =10.4-15.4) between populations divided by an 11-km valley. Models of gene flow based on regional topography and movement barriers suggested that nine populations of bighorn sheep in northwestern Sonora are linked by dispersal with those in neighboring Arizona. Disruption of transboundary movement corridors by impermeable fencing would isolate some populations on the Arizona side. Connectivity for other species with similar movement abilities and spatial distributions may be affected by border development, yet mitigation strategies could address needs of wildlife and humans.

Gust Alleviation Using Direct Gust Measurement

NASA Technical Reports Server (NTRS)

Hoppe, Sven Marco

2000-01-01

The increasing competition in the market of civil aircraft leads to operating efficiency and passenger comfort being very important sales arguments. Continuous developments in jet propulsion technology helped to reduce energy consumption, as well as noise and vibrations due to the engines. The main problem with respect to ride comfort is, however, the transmittance of accelerations and jerkiness imposed by atmospheric turbulence from the wings to the fuselage. This 'gust' is also a design constraint: Light airplane structures help to save, energy, but are more critical to resist the loads imposed by turbulence. For both reasons, efficient gust alleviation is necessary to improve the performance of modern aircraft. Gust can be seen as a change in the angle of attack or as an additional varying vertical component of the headwind. The effect of gust can be very strong, since the same aerodynamic forces that keep the airplane flying are involved. Event though the frequency range of those changes is quite low, it is impossible for the pilot to alleviate gust manually. Besides, most of the time during the flight, the, autopilot maintains course and the attitude of flight. Certainly, most autopilots should be capable of damping the roughest parts of turbulence, but they are unable to provide satisfactory results in that field. A promising extension should be the application of subsidiary, control, where the inner (faster) control loop alleviates turbulence and the outer (slower) loop controls the attitude of flight. Besides the mentioned ride comfort, another reason for gust alleviation with respect to the fuselage is the sensibility of electrical devices to vibration and high values of acceleration. Many modern airplane designs--especially inherently instable military aircraft--are highly dependent on avionics. The lifetime and the reliability of these systems is thus essential.

A versatile dual-species Zeeman slower for caesium and ytterbium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopkins, S. A., E-mail: s.a.hopkins@durham.ac.uk; Butler, K.; Guttridge, A.

2016-04-15

We describe the design, construction, and operation of a versatile dual-species Zeeman slower for both Cs and Yb, which is easily adaptable for use with other alkali metals and alkaline earths. With the aid of analytic models and numerical simulation of decelerator action, we highlight several real-world problems affecting the performance of a slower and discuss effective solutions. To capture Yb into a magneto-optical trap (MOT), we use the broad {sup 1}S{sub 0} to {sup 1}P{sub 1} transition at 399 nm for the slower and the narrow {sup 1}S{sub 0} to {sup 3}P{sub 1} intercombination line at 556 nm formore » the MOT. The Cs MOT and slower both use the D2 line (6{sup 2}S{sub 1/2} to 6{sup 2}P{sub 3/2}) at 852 nm. The slower can be switched between loading Yb or Cs in under 0.1 s. We demonstrate that within a few seconds the Zeeman slower loads more than 10{sup 9} Yb atoms and 10{sup 8} Cs atoms into their respective MOTs. These are ideal starting numbers for further experiments on ultracold mixtures and molecules.« less

Unraveling the role of protein dynamics in dihydrofolate reductase catalysis

PubMed Central

Luk, Louis Y. P.; Javier Ruiz-Pernía, J.; Dawson, William M.; Roca, Maite; Loveridge, E. Joel; Glowacki, David R.; Harvey, Jeremy N.; Mulholland, Adrian J.; Tuñón, Iñaki; Moliner, Vicent; Allemann, Rudolf K.

2013-01-01

Protein dynamics have controversially been proposed to be at the heart of enzyme catalysis, but identification and analysis of dynamical effects in enzyme-catalyzed reactions have proved very challenging. Here, we tackle this question by comparing an enzyme with its heavy (15N, 13C, 2H substituted) counterpart, providing a subtle probe of dynamics. The crucial hydride transfer step of the reaction (the chemical step) occurs more slowly in the heavy enzyme. A combination of experimental results, quantum mechanics/molecular mechanics simulations, and theoretical analyses identify the origins of the observed differences in reactivity. The generally slightly slower reaction in the heavy enzyme reflects differences in environmental coupling to the hydride transfer step. Importantly, the barrier and contribution of quantum tunneling are not affected, indicating no significant role for “promoting motions” in driving tunneling or modulating the barrier. The chemical step is slower in the heavy enzyme because protein motions coupled to the reaction coordinate are slower. The fact that the heavy enzyme is only slightly less active than its light counterpart shows that protein dynamics have a small, but measurable, effect on the chemical reaction rate. PMID:24065822

Hubble Captures Rare Triple-Moon Conjunction

NASA Image and Video Library

2015-02-06

Three moons and their shadows parade across Jupiter near the end of the event at 07:10 UT on January 24, 2015. Europa has entered the frame at lower left. Slower-moving Callisto is above and to the right of Europa. Fastest-moving Io is approaching the eastern limb of the planet. Europa's shadow is toward the left side of the image and Callisto's shadow to the right. (The moons' orbital velocities are proportionally slower with increasing distance from the planet.) Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) More info: Firing off a string of snapshots like a sports photographer at a NASCAR race, NASA's Hubble Space Telescope captured a rare look at three of Jupiter's largest moons zipping across the banded face of the gas-giant planet: Europa, Callisto, and Io. Jupiter's four largest moons can commonly be seen transiting the face of the giant planet and casting shadows onto its cloud tops. However, seeing three moons transiting the face of Jupiter at the same time is rare, occurring only once or twice a decade. Missing from the sequence, taken on January 24, 2015, is the moon Ganymede that was too far from Jupiter in angular separation to be part of the conjunction. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Intense flight and endotoxin injection elicit similar effects on leukocyte distributions but dissimilar effects on plasma-based immunological indices in pigeons.

PubMed

Matson, Kevin D; Horrocks, Nicholas P C; Tieleman, B Irene; Haase, Eberhard

2012-11-01

Most birds rely on flight for survival. Yet as an energetically taxing and physiologically integrative process, flight has many repercussions. Studying pigeons (Columba livia) and employing physiological and immunological indices that are relevant to ecologists working with wild birds, we determined what, if any, acute immune-like responses result from bouts of intense, non-migratory flight. We compared the effects of flight with the effects of a simulated bacterial infection. We also investigated indices in terms of their post-flight changes within individuals and their relationship with flight speed among individuals. Compared to un-flown controls, flown birds exhibited significant elevations in numbers of heterophils relative to numbers of lymphocytes and significant reductions in numbers of eosinophils and monocytes. Furthermore, within-individual changes in concentrations of an acute phase protein were greater in flown birds than in controls. However, none of the flight-affected indices showed any evidence of being related to flight speed. While some of the effects of flight were comparable to the effects of the simulated bacterial infection, other effects were observed only after one of these two physiological challenges. Our study suggests that flight by pigeons yields immune-like responses, and these responses have the potential to complicate the conclusions drawn by ecologists regarding immune function in free-living birds. Still, a better understanding of the repercussions of flight can help clarify the ties between the physiology of exercise and the disease ecology of migration and will ultimately assist in the broader goal of accounting for immunological variation within and among species.

Experiment K-6-16. Morphological examination of rat testes. The effect of Cosmos 1887 flight on spermatogonial population and testosterone level in rat testes

NASA Technical Reports Server (NTRS)

Philpott, D. E.; Kato, K.; Stevenson, J.; Vasques, M.; Sapp, W.; Williams, C.; Popova, I. A.; Serova, L. V.

1990-01-01

Testes from rats flown on Cosmos 1887 for twelve and a half days were compared to basal control, synchronous control and vivarium maintained rats. When the mean weights of flight testes, normalized for weight/100 gms, were compared to the vivarium controls they were 6.7 percent lighter. Although the flight testes were lighter than the synchronous, the difference is not significant. Counts of spermatogonial cells from 5 animals in each group revealed a 4 percent decrease in flight compared to vivarium controls. In both cases the t-Test significance was less than 0.02. The serum testosterone levels of all animals (flight, synchronous and vivarium) were significantly below the basal controls.

New model of flap-gliding flight.

PubMed

Sachs, Gottfried

2015-07-21

A new modelling approach is presented for describing flap-gliding flight in birds and the associated mechanical energy cost of travelling. The new approach is based on the difference in the drag characteristics between flapping and non-flapping due to the drag increase caused by flapping. Thus, the possibility of a gliding flight phase, as it exists in flap-gliding flight, yields a performance advantage resulting from the decrease in the drag when compared with continuous flapping flight. Introducing an appropriate non-dimensionalization for the mathematical relations describing flap-gliding flight, results and findings of generally valid nature are derived. It is shown that there is an energy saving of flap-gliding flight in the entire speed range compared to continuous flapping flight. The energy saving reaches the highest level in the lower speed region. The travelling speed of flap-gliding flight is composed of the weighted average of the differing speeds in the flapping and gliding phases. Furthermore, the maximum range performance achievable with flap-gliding flight and the associated optimal travelling speed are determined. Copyright © 2015 Elsevier Ltd. All rights reserved.

Green Flight Challenge

NASA Image and Video Library

2011-09-25

Brien A. Seeley M.D., President of Comparative Aircraft Flight Efficiency (CAFE) Foundation briefs pilots and ground crew prior to competition as part of the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Monday, Sept. 26, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-25

Brien A. Seeley M.D., President of Comparative Aircraft Flight Efficiency (CAFE) Foundation, right, briefs pilots and ground crew prior to competition as part of the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Monday, Sept. 26, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Yunteng; Zhang, Jie; Li, Yang

2015-08-15

We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He{sub 2}{sup +} and He{sub 4}{sup +}, which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl{sub 4} doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He){sub n}C{sup +}, (He){sub n}Cl{sup +}, and (He){sub n}CCl{sup +}. Usingmore » both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.« less

Current best management practices for harvesting and storing dry hay: a research review

USDA-ARS?s Scientific Manuscript database

The production of high-quality grass or legume hays in humid environments is complicated by slower drying rates, and increased probability of rainfall events compared to hay produced under arid climatic conditions. As a result, hay producers in humid environments often face the management dilemma of...

Maltase-glucoamylase: Mucosal regulator of prandial starch glucogenesis and complementary hepatic gluconeogenesis of mice

USDA-ARS?s Scientific Manuscript database

It was hypothesized that the slower rate of starch digestion by residual sucraseisomaltase (Si) maltase failed to fully regulate gluconeogenesis. In the present study the rate of gluconeogenesis was measured directly (J Appl Physiol 104: 944-951, 2008) and compared with exogenous glucose derived fro...

Stress sensitivity in Toxoplasma gondii is linked to its uniquely flexible life cycle

USDA-ARS?s Scientific Manuscript database

Hammondia hammondi is the nearest relative of Toxoplasma gondii, but unlike T. gondii is obligately heteroxenous. We have compared H. hammondi and T. gondii development in vitro and identified multiple H. hammondi-specific growth states. Despite replicating slower than T. gondii, H. hammondi was res...

Salivary habituation to food stimuli in successful weight loss maintainers, obese and normal-weight adults

PubMed Central

Bond, DS; Raynor, HA; McCaffery, JM; Wing, RR

2017-01-01

Objective Research shows that slower habituation of salivary responses to food stimuli is related to greater energy intake and that obese (Ob) individuals habituate slower than those of normal weight (NW). No study has examined habituation rates in weight loss maintainers (WLMs) who have reduced from obese to normal weight, relative to those who are Ob or NW. Design Salivation to two baseline water trials and 10 lemon-flavored lollipop trials were studied in 14 WLMs, 15 Ob and 18 NW individuals comparable in age, gender and ethnicity. Linear mixed models were used to compare WLMs with Ob and NW groups. Results Salivation in the WLM and NW groups decreased significantly (for both P <0.005) across trials, indicative of habituation. Salivary responses in the Ob group did not habituate (P=0.46). When compared with Ob group, WLMs showed a quicker reduction in salivation (P<0.05). WLM and NW groups did not differ in habituation rate (P=0.49). Conclusions WLMs have habituation rates that are comparable to NW individuals without previous history of obesity, and show quicker habituation than those who are currently obese. These results suggest that physiological responses to food may ‘normalize’ with successful weight loss maintenance. PMID:20010900

Effects of Nanotexture on Electrical Profiling of Single Tumor Cell and Detection of Cancer from Blood in Microfluidic Channels

PubMed Central

Islam, Muhymin; Motasim Bellah, Mohammad; Sajid, Adeel; Raziul Hasan, Mohammad; Kim, Young-tae; Iqbal, Samir M.

2015-01-01

Microfluidic channels have been implemented to detect cancer cells from blood using electrical measurement of each single cell from the sample. Every cell provided characteristic current profile based on its mechano-physical properties. Cancer cells not only showed higher translocation time and peak amplitude compared to blood cells, their pulse shape was also distinctively different. Prevalent microfluidic channels are plain but we created nanotexture on the channel walls using micro reactive ion etching (micro-RIE). The translocation behaviors of the metastatic renal cancer cells through plain and nanotextured PDMS microchannels showed clear differences. Nanotexture enhanced the cell-surface interactions and more than 50% tumor cells exhibited slower translocation through nanotextured channels compared to plain devices. On the other hand, most of the blood cells had very similar characteristics in both channels. Only 7.63% blood cells had slower translocation in nanotextured microchannels. The tumor cell detection efficiency from whole blood increased by 14% in nanotextured microchannels compared to plain channels. This interesting effect of nanotexture on translocation behavior of tumor cells is important for the early detection of cancer. PMID:26373820

Comparative evaluation of Space Transportation System (STS)-3 flight and acoustic test random vibration response of the OSS-1 payload

NASA Technical Reports Server (NTRS)

On, F. J.

1983-01-01

A comparative evaluation of the Space Transportation System (STS)-3 flight and acoustic test random vibration response of the Office of Space Science-1 (OSS-1) payload is presented. The results provide insight into the characteristics of vibroacoustic response of pallet payload components in the payload bay during STS flights.

Post-Flight Assessment of Low Density Supersonic Decelerator Flight Dynamics Test 2 Simulation

NASA Technical Reports Server (NTRS)

Dutta, Soumyo; Bowes, Angela L.; White, Joseph P.; Striepe, Scott A.; Queen, Eric M.; O'Farrel, Clara; Ivanov, Mark C.

2016-01-01

NASA's Low Density Supersonic Decelerator (LDSD) project conducted its second Supersonic Flight Dynamics Test (SFDT-2) on June 8, 2015. The Program to Optimize Simulated Trajectories II (POST2) was one of the flight dynamics tools used to simulate and predict the flight performance and was a major tool used in the post-flight assessment of the flight trajectory. This paper compares the simulation predictions with the reconstructed trajectory. Additionally, off-nominal conditions seen during flight are modeled in the simulation to reconcile the predictions with flight data. These analyses are beneficial to characterize the results of the flight test and to improve the simulation and targeting of the subsequent LDSD flights.

The challenges of the first migration: movement and behaviour of juvenile vs. adult white storks with insights regarding juvenile mortality.

PubMed

Rotics, Shay; Kaatz, Michael; Resheff, Yehezkel S; Turjeman, Sondra Feldman; Zurell, Damaris; Sapir, Nir; Eggers, Ute; Flack, Andrea; Fiedler, Wolfgang; Jeltsch, Florian; Wikelski, Martin; Nathan, Ran

2016-07-01

Migration conveys an immense challenge, especially for juvenile birds coping with enduring and risky journeys shortly after fledging. Accordingly, juveniles exhibit considerably lower survival rates compared to adults, particularly during migration. Juvenile white storks (Ciconia ciconia), which are known to rely on adults during their first fall migration presumably for navigational purposes, also display much lower annual survival than adults. Using detailed GPS and body acceleration data, we examined the patterns and potential causes of age-related differences in fall migration properties of white storks by comparing first-year juveniles and adults. We compared juvenile and adult parameters of movement, behaviour and energy expenditure (estimated from overall dynamic body acceleration) and placed this in the context of the juveniles' lower survival rate. Juveniles used flapping flight vs. soaring flight 23% more than adults and were estimated to expend 14% more energy during flight. Juveniles did not compensate for their higher flight costs by increased refuelling or resting during migration. When juveniles and adults migrated together in the same flock, the juvenile flew mostly behind the adult and was left behind when they separated. Juveniles showed greater improvement in flight efficiency throughout migration compared to adults which appears crucial because juveniles exhibiting higher flight costs suffered increased mortality. Our findings demonstrate the conflict between the juveniles' inferior flight skills and their urge to keep up with mixed adult-juvenile flocks. We suggest that increased flight costs are an important proximate cause of juvenile mortality in white storks and likely in other soaring migrants and that natural selection is operating on juvenile variation in flight efficiency. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

[The comparative characteristics of crystalline lens and limb regeneration in newts operated on before and after the completion of an orbital space flight].

PubMed

Tuchkova, S Ia; Brushlinskaia, N V; Grigorian, E N; Mitashov, V I

1994-01-01

It has been already established that a tendency towards synchronization and acceleration of the forelimb and lens regeneration is observed in Pleurodeles waltlii under the effect of space flight factors. Here we present the results obtained after 16-day space flight of two groups of newts. In animals of group I forelimbs were amputated and lenses were removed 14 and 7 days before the space flight, respectively. Intact animals of group II were operated on the day of the sputnik landing. Regenerates of the flight and corresponding control animals were fixed at the same time after the operation. For evaluation of the regeneration rate morphological criteria were used: morphological stages of regeneration were compared in the experiment and the control. For quantitative assay of the regeneration rate we determined the index of nuclei labelled with 3H-thymidine in the blastema and lens rudiment cells and used morphometry of the lens regenerates. Acceleration of forelimb and lens regeneration was observed in both groups of animals. In group II more than two-fold increase of the index of labelled nuclei was found in the blastema cells at the comparable stages of development. The size of lens regenerates in flight groups I and II exceeded reliably those in the control animals. The results obtained suggest a prolonged effect of the space flight factors on forelimb and lens regeneration. Under the conditions of space flight the lens regenerates reached more advanced stages of regeneration, as compared with the control animals operated after the space flight. These results also suggest acceleration of regeneration in lower vertebrates.

How Cheap Is Soaring Flight in Raptors? A Preliminary Investigation in Freely-Flying Vultures

PubMed Central

Duriez, Olivier; Kato, Akiko; Tromp, Clara; Dell'Omo, Giacomo; Vyssotski, Alexei L.; Sarrazin, François; Ropert-Coudert, Yan

2014-01-01

Measuring the costs of soaring, gliding and flapping flight in raptors is challenging, but essential for understanding their ecology. Among raptors, vultures are scavengers that have evolved highly efficient soaring-gliding flight techniques to minimize energy costs to find unpredictable food resources. Using electrocardiogram, GPS and accelerometer bio-loggers, we report the heart rate (HR) of captive griffon vultures (Gyps fulvus and G. himalayensis) trained for freely-flying. HR increased three-fold at take-off (characterized by prolonged flapping flight) and landing (>300 beats-per-minute, (bpm)) compared to baseline levels (80–100 bpm). However, within 10 minutes after the initial flapping phase, HR in soaring/gliding flight dropped to values similar to baseline levels, i.e. slightly lower than theoretically expected. However, the extremely rapid decrease in HR was unexpected, when compared with other marine gliders, such as albatrosses. Weather conditions influenced flight performance and HR was noticeably higher during cloudy compared to sunny conditions when prolonged soaring flight is made easier by thermal ascending air currents. Soaring as a cheap locomotory mode is a crucial adaptation for vultures who spend so long on the wing for wide-ranging movements to find food. PMID:24454760

How cheap is soaring flight in raptors? A preliminary investigation in freely-flying vultures.

PubMed

Duriez, Olivier; Kato, Akiko; Tromp, Clara; Dell'Omo, Giacomo; Vyssotski, Alexei L; Sarrazin, François; Ropert-Coudert, Yan

2014-01-01

Measuring the costs of soaring, gliding and flapping flight in raptors is challenging, but essential for understanding their ecology. Among raptors, vultures are scavengers that have evolved highly efficient soaring-gliding flight techniques to minimize energy costs to find unpredictable food resources. Using electrocardiogram, GPS and accelerometer bio-loggers, we report the heart rate (HR) of captive griffon vultures (Gyps fulvus and G. himalayensis) trained for freely-flying. HR increased three-fold at take-off (characterized by prolonged flapping flight) and landing (>300 beats-per-minute, (bpm)) compared to baseline levels (80-100 bpm). However, within 10 minutes after the initial flapping phase, HR in soaring/gliding flight dropped to values similar to baseline levels, i.e. slightly lower than theoretically expected. However, the extremely rapid decrease in HR was unexpected, when compared with other marine gliders, such as albatrosses. Weather conditions influenced flight performance and HR was noticeably higher during cloudy compared to sunny conditions when prolonged soaring flight is made easier by thermal ascending air currents. Soaring as a cheap locomotory mode is a crucial adaptation for vultures who spend so long on the wing for wide-ranging movements to find food.

The Apollo 16 microbial response to space environment experiment

NASA Technical Reports Server (NTRS)

Taylor, G. R.

1975-01-01

The effect was evaluated of a particular space flight on the survival rate of nine different species. Although a reasonable variety of organisms (viruses, yeasts, filamentous fungi, bacteria, and an invertebrate) were tested under several different conditions, no statistically valid differences could be detected in the survival of flight samples when compared to corresponding ground-based controls. In general, these evaluations were based on multiple observations of from ten to thirty replicates of up to one million cells each. While the results conflict with those of certain other space flight investigations, it is observed that the conditions of a particular space flight cannot be exactly duplicated, and therefore results from different flights are not directly comparable.

Altitude exposures during commercial flight: a reappraisal.

PubMed

Hampson, Neil B; Kregenow, David A; Mahoney, Anne M; Kirtland, Steven H; Horan, Kathleen L; Holm, James R; Gerbino, Anthony J

2013-01-01

Hypobaric hypoxia during commercial air travel has the potential to cause or worsen hypoxemia in individuals with pre-existing cardiopulmonary compromise. Knowledge of cabin altitude pressures aboard contemporary flights is essential to counseling patients accurately about flying safety. The objective of the study was to measure peak cabin altitudes during U.S. domestic commercial flights on a variety of aircraft. A handheld mountaineering altimeter was carried by the investigators in the plane cabin during commercial air travel and peak cabin altitude measured. The values were then compared between aircraft models, aircraft classes, and distances flown. The average peak cabin altitude on 207 flights aboard 17 different aircraft was 6341 +/- 1813 ft (1933 m +/- 553 m), significantly higher than when measured in a similar fashion in 1988. Peak cabin altitude was significantly higher for flights longer than 750 mi (7085 +/- 801 ft) compared to shorter flights (5160 +/- 2290 ft/1573 +/- 698 m). Cabin altitude increased linearly with flight distance for flights up to 750 mi in length, but was independent of flight distance for flights exceeding 750 mi. Peak cabin altitude was less than 5000 ft (1524 m) in 70% of flights shorter than 500 mi. Peak cabin altitudes greater than 8000 ft (2438 m) were measured on approximately 10% of the total flights. Peak cabin altitude on commercial aircraft flights has risen over time. Cabin altitude is lower with flights of shorter distance. Physicians should take these factors into account when determining an individual's need for supplemental oxygen during commercial air travel.

Surface tension dominates insect flight on fluid interfaces.

PubMed

Mukundarajan, Haripriya; Bardon, Thibaut C; Kim, Dong Hyun; Prakash, Manu

2016-03-01

Flight on the 2D air-water interface, with body weight supported by surface tension, is a unique locomotion strategy well adapted for the environmental niche on the surface of water. Although previously described in aquatic insects like stoneflies, the biomechanics of interfacial flight has never been analysed. Here, we report interfacial flight as an adapted behaviour in waterlily beetles (Galerucella nymphaeae) which are also dexterous airborne fliers. We present the first quantitative biomechanical model of interfacial flight in insects, uncovering an intricate interplay of capillary, aerodynamic and neuromuscular forces. We show that waterlily beetles use their tarsal claws to attach themselves to the interface, via a fluid contact line pinned at the claw. We investigate the kinematics of interfacial flight trajectories using high-speed imaging and construct a mathematical model describing the flight dynamics. Our results show that non-linear surface tension forces make interfacial flight energetically expensive compared with airborne flight at the relatively high speeds characteristic of waterlily beetles, and cause chaotic dynamics to arise naturally in these regimes. We identify the crucial roles of capillary-gravity wave drag and oscillatory surface tension forces which dominate interfacial flight, showing that the air-water interface presents a radically modified force landscape for flapping wing flight compared with air. © 2016. Published by The Company of Biologists Ltd.

Surface tension dominates insect flight on fluid interfaces

PubMed Central

Mukundarajan, Haripriya; Bardon, Thibaut C.; Kim, Dong Hyun; Prakash, Manu

2016-01-01

ABSTRACT Flight on the 2D air–water interface, with body weight supported by surface tension, is a unique locomotion strategy well adapted for the environmental niche on the surface of water. Although previously described in aquatic insects like stoneflies, the biomechanics of interfacial flight has never been analysed. Here, we report interfacial flight as an adapted behaviour in waterlily beetles (Galerucella nymphaeae) which are also dexterous airborne fliers. We present the first quantitative biomechanical model of interfacial flight in insects, uncovering an intricate interplay of capillary, aerodynamic and neuromuscular forces. We show that waterlily beetles use their tarsal claws to attach themselves to the interface, via a fluid contact line pinned at the claw. We investigate the kinematics of interfacial flight trajectories using high-speed imaging and construct a mathematical model describing the flight dynamics. Our results show that non-linear surface tension forces make interfacial flight energetically expensive compared with airborne flight at the relatively high speeds characteristic of waterlily beetles, and cause chaotic dynamics to arise naturally in these regimes. We identify the crucial roles of capillary–gravity wave drag and oscillatory surface tension forces which dominate interfacial flight, showing that the air–water interface presents a radically modified force landscape for flapping wing flight compared with air. PMID:26936640

Contrasting Levels of Molecular Evolution on the Mouse X Chromosome

PubMed Central

Larson, Erica L.; Vanderpool, Dan; Keeble, Sara; Zhou, Meng; Sarver, Brice A. J.; Smith, Andrew D.; Dean, Matthew D.; Good, Jeffrey M.

2016-01-01

The mammalian X chromosome has unusual evolutionary dynamics compared to autosomes. Faster-X evolution of spermatogenic protein-coding genes is known to be most pronounced for genes expressed late in spermatogenesis, but it is unclear if these patterns extend to other forms of molecular divergence. We tested for faster-X evolution in mice spanning three different forms of molecular evolution—divergence in protein sequence, gene expression, and DNA methylation—across different developmental stages of spermatogenesis. We used FACS to isolate individual cell populations and then generated cell-specific transcriptome profiles across different stages of spermatogenesis in two subspecies of house mice (Mus musculus), thereby overcoming a fundamental limitation of previous studies on whole tissues. We found faster-X protein evolution at all stages of spermatogenesis and faster-late protein evolution for both X-linked and autosomal genes. In contrast, there was less expression divergence late in spermatogenesis (slower late) on the X chromosome and for autosomal genes expressed primarily in testis (testis-biased). We argue that slower-late expression divergence reflects strong regulatory constraints imposed during this critical stage of sperm development and that these constraints are particularly acute on the tightly regulated sex chromosomes. We also found slower-X DNA methylation divergence based on genome-wide bisulfite sequencing of sperm from two species of mice (M. musculus and M. spretus), although it is unclear whether slower-X DNA methylation reflects development constraints in sperm or other X-linked phenomena. Our study clarifies key differences in patterns of regulatory and protein evolution across spermatogenesis that are likely to have important consequences for mammalian sex chromosome evolution, male fertility, and speciation. PMID:27317678

Comparison between Hydrogen and Methane Fuels in a 3-D Scramjet at Mach 8

DTIC Science & Technology

2016-06-24

performance of small chained hydrocarbons ( ethylene and methane) was compared with hydrogen to establish the importance of its lower specific energy...Report Comparison between hydrogen, methane and ethylene fuels in a 3-D Scramjet at Mach 8 Professor Michael K. Smart Chair of Hypersonic Propulsion...hydrocarbons ( ethylene and methane) was compared with hydrogen to establish the importance of its lower specific energy content and slower reaction

Supersonic Flight Dynamics Test 1 - Post-Flight Assessment of Simulation Performance

NASA Technical Reports Server (NTRS)

Dutta, Soumyo; Bowes, Angela L.; Striepe, Scott A.; Davis, Jody L.; Queen, Eric M.; Blood, Eric M.; Ivanov, Mark C.

2015-01-01

NASA's Low Density Supersonic Decelerator (LDSD) project conducted its first Supersonic Flight Dynamics Test (SFDT-1) on June 28, 2014. Program to Optimize Simulated Trajectories II (POST2) was one of the flight dynamics codes used to simulate and predict the flight performance and Monte Carlo analysis was used to characterize the potential flight conditions experienced by the test vehicle. This paper compares the simulation predictions with the reconstructed trajectory of SFDT-1. Additionally, off-nominal conditions seen during flight are modeled in post-flight simulations to find the primary contributors that reconcile the simulation with flight data. The results of these analyses are beneficial for the pre-flight simulation and targeting of the follow-on SFDT flights currently scheduled for summer 2015.

Predicting hypoxaemia during flights in children with cystic fibrosis

PubMed Central

Buchdahl, R; Babiker, A; Bush, A; Cramer, D

2001-01-01

BACKGROUND—We have previously suggested that it is possible to predict oxygen desaturation during flight in children with cystic fibrosis and chronic lung disease by non-invasive measurement of oxygen saturation following inhalation of 15% oxygen—the pre-flight hypoxic challenge. This study reports on the results of measurements over 5years.
METHODS—The study comprised a pre-flight hypoxic challenge measuring oxygen saturation by finger tip pulse oximetry (SpO2) during tidal breathing of 15% oxygen in nitrogen and spirometric testing 1 month before the flight followed by SpO2 measurements during intercontinental flights to and from holidays abroad with children in wake and sleep states.
RESULTS—Pre-flight tests were completed on 87 children with cystic fibrosis. Desaturation of <90% occurred in 10 children at some stage during the flight, three of whom received supplementary oxygen. Using a cut off SpO2 of 90%, the pre-flight hypoxic challenge correctly predicted desaturation in only two of these children. The sensitivity and specificity of the pre-flight hypoxic challenge were 20% and 99%, respectively, compared with 70% and 96% for spirometric tests (using a cut off for forced expiratory volume in 1 second (FEV1) of <50% predicted). Overall, pre-flight spirometric tests were a better predictor of desaturation during flight with the area under the Receiver Operating Characteristic (ROC) curve of 0.89 compared with 0.73 for the hypoxic challenge test.
CONCLUSIONS—In this group of subjects pre-flight spirometric testing was a better predictor of desaturation during flight than the pre-flight hypoxic challenge.

 PMID:11641514

Effect of nitrogen fertilization and fungicides on Botryosphaeria stem blight lesion development on detached stems

USDA-ARS?s Scientific Manuscript database

: Botryosphaeria stem blight is a destructive disease of blueberries that has not been well managed with fungicides. Field observations showed that stem blight is more severe on vigorously growing plants than on slower growing plants. Detached stem assays were used to compare the effect of fertil...

Effect of nitrogen fertilization and fungicides on Botryosphaeria stem blight lesion development on detached blueberry stems

USDA-ARS?s Scientific Manuscript database

Botryosphaeria stem blight is a destructive disease of blueberries. Field observations indicate stem blight is more severe on vigorous plants than on slower growing plants. Two studies compared the effect of two types of fertilizers applied at four rates and nine fungicides on lesion development fo...

The Development of Rhythmic Attending in Auditory Sequences: Attunement, Referent Period, Focal Attending.

ERIC Educational Resources Information Center

Drake, Carolyn; Jones, Mari Riess; Baruch, Clarisse

2000-01-01

Extends dynamic attending theory to developmental questions concerning tempo and time hierarchies. Compares performance of 4- to 10-year-olds, and adults on dynamic attending activities. Suggests that growth trends could be expressed in terms of listeners' engagement of slower attending oscillators with age and musical experience, accompanied by…

Impaired Visual Attention in Children with Dyslexia.

ERIC Educational Resources Information Center

Heiervang, Einar; Hugdahl, Kenneth

2003-01-01

A cue-target visual attention task was administered to 25 children (ages 10-12) with dyslexia. Results showed a general pattern of slower responses in the children with dyslexia compared to controls. Subjects also had longer reaction times in the short and long cue-target interval conditions (covert and overt shift of attention). (Contains…

Southern pulpwood production, 1980

Treesearch

Victor A. Rudis

1980-01-01

Total southern pulpwood production in 1980 was 54.5 million cords, an amount comparable to the 54.3 million cords reported in 1979. This slower growth is in marked contrast to the 3 to 12 percent growth which occurred in the years since 1975 (fig. 1). Softwood roundwood continues to be the most important contributor to annual production.

Distinctive ribonucleic acid patterns of human rotavirus subgroups 1 and 2.

PubMed Central

Kalica, A R; Greenberg, H B; Espejo, R T; Flores, J; Wyatt, R G; Kapikian, A Z; Chanock, R M

1981-01-01

The ribonucleic acid migration patterns of 7 subgroup 1 and 16 subgroup 2 human rotaviruses recovered from four geographic areas were compared. The subgroup 1 ribonucleic acid patterns had strikingly slower-moving segments 10 and 11, suggesting a correlation between the ribonucleic acid pattern and the subgroup specificity. Images PMID:6270002

In Vivo Protein Dynamics on the Nanometer Length Scale and Nanosecond Time Scale

DOE PAGES

Anunciado, Divina B.; Nyugen, Vyncent P.; Hurst, Gregory B.; ...

2017-04-07

Selectively labeled GroEL protein was produced in living deuterated bacterial cells to enhance its neutron scattering signal above that of the intracellular milieu. Quasi-elastic neutron scattering shows that the in-cell diffusion coefficient of GroEL was (4.7 ± 0.3) × 10 –12 m 2/s, a factor of 4 slower than its diffusion coefficient in buffer solution. Furthermore, for internal protein dynamics we see a relaxation time of (65 ± 6) ps, a factor of 2 slower compared to the protein in solution. Comparison to the literature suggests that the effective diffusivity of proteins depends on the length and time scale beingmore » probed. Retardation of in-cell diffusion compared to the buffer becomes more significant with the increasing probe length scale, suggesting that intracellular diffusion of biomolecules is nonuniform over the cellular volume. This approach outlined here enables investigation of protein dynamics within living cells to open up new lines of research using “in-cell neutron scattering” to study the dynamics of complex biomolecular systems.« less

In Vivo Protein Dynamics on the Nanometer Length Scale and Nanosecond Time Scale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anunciado, Divina B.; Nyugen, Vyncent P.; Hurst, Gregory B.

Selectively labeled GroEL protein was produced in living deuterated bacterial cells to enhance its neutron scattering signal above that of the intracellular milieu. Quasi-elastic neutron scattering shows that the in-cell diffusion coefficient of GroEL was (4.7 ± 0.3) × 10 –12 m 2/s, a factor of 4 slower than its diffusion coefficient in buffer solution. Furthermore, for internal protein dynamics we see a relaxation time of (65 ± 6) ps, a factor of 2 slower compared to the protein in solution. Comparison to the literature suggests that the effective diffusivity of proteins depends on the length and time scale beingmore » probed. Retardation of in-cell diffusion compared to the buffer becomes more significant with the increasing probe length scale, suggesting that intracellular diffusion of biomolecules is nonuniform over the cellular volume. This approach outlined here enables investigation of protein dynamics within living cells to open up new lines of research using “in-cell neutron scattering” to study the dynamics of complex biomolecular systems.« less

Beta-2 adrenoceptor genotype and progress in term and late preterm active labor

PubMed Central

MILLER, Russell S.; SMILEY, Richard M.; DANIEL, Danette; WENG, Chunhua; EMALA, Charles W.; BLOUIN, Jean-Louis; FLOOD, Pamela D.

2011-01-01

OBJECTIVE To evaluate whether beta-2 adrenoceptor genotype at a functional polymorphic site encoding for amino acid residue 16 influences rate of cervical dilatation in term and late preterm active labor. STUDY DESIGN Subjects that underwent vaginal delivery at 34 or greater weeks gestational age between May, 2006, and August, 2007, were identified. Each subject had provided venous blood from which DNA was extracted for beta-2 adrenoceptor genotyping. Digital cervical examinations with paired examination times were collected from intrapartum records. Rate of cervical dilatation in active labor was determined using linear regression and rates were compared between genotype groups. RESULTS Among 401 subjects with satisfactory genotype and intrapartum data, overall rate of active labor was 0.76+/−0.01 cm/hr. When labor was compared by genotype, homozygous Arg/Arg16 subjects progressed at a slower rate (0.64+/−0.03 cm/hr) than all other pooled genotypes (0.8+/−0.02 cm/hr). CONCLUSION Homozygous beta-2 adrenoceptor genotype encoding for Arg/Arg16 was associated with slower progress in active labor. PMID:21600547

ALMA discovery of a rotating SO/SO2 flow in HH212. A possible MHD disk wind?

NASA Astrophysics Data System (ADS)

Tabone, B.; Cabrit, S.; Bianchi, E.; Ferreira, J.; Pineau des Forêts, G.; Codella, C.; Gusdorf, A.; Gueth, F.; Podio, L.; Chapillon, E.

2017-11-01

We wish to constrain the possible contribution of a magnetohydrodynamic disk wind (DW) to the HH212 molecular jet. We mapped the flow base with ALMA Cycle 4 at 0.̋13 60 au resolution and compared these observations with synthetic DW predictions. We identified, in SO/SO2, a rotating flow that is wider and slower than the axial SiO jet. The broad outflow cavity seen in C34S is not carved by a fast wide-angle wind but by this slower agent. Rotation signatures may be fitted by a DW of a moderate lever arm launched out to 40 au with SiO tracing dust-free streamlines from 0.05-0.3 au. Such a DW could limit the core-to-star efficiency to ≤50%.

Effects of Cascaded Voltage Collapse and Protection of Many Induction Machine Loads upon Load Characteristics Viewed from Bulk Transmission System

NASA Astrophysics Data System (ADS)

Kumano, Teruhisa

As known well, two of the fundamental processes which give rise to voltage collapse in power systems are the on load tap changers of transformers and dynamic characteristics of loads such as induction machines. It has been well established that, comparing among these two, the former makes slower collapse while the latter makes faster. However, in realistic situations, the load level of each induction machine is not uniform and it is well expected that only a part of loads collapses first, followed by collapse process of each load which did not go into instability during the preceding collapses. In such situations the over all equivalent collapse behavior viewed from bulk transmission level becomes somewhat different from the simple collapse driven by one aggregated induction machine. This paper studies the process of cascaded voltage collapse among many induction machines by time simulation, where load distribution on a feeder line is modeled by several hundreds of induction machines and static impedance loads. It is shown that in some cases voltage collapse really cascades among induction machines, where the macroscopic load dynamics viewed from upper voltage level makes slower collapse than expected by the aggregated load model. Also shown is the effects of machine protection of induction machines, which also makes slower collapse.

Direct observation of the photodegradation of anthracene and pyrene adsorbed onto mangrove leaves.

PubMed

Wang, Ping; Wu, Tun-Hua; Zhang, Yong

2014-01-01

An established synchronous fluorimetry method was used for in situ investigation of the photodegradation of pyrene (PYR) and anthracene (ANT) adsorbed onto fresh leaves of the seedlings of two mangrove species, Aegiceras corniculatum (L.) Blanco (Ac) and Kandelia obovata (Ko) in multicomponent mixtures (mixture of the ANT and PYR). Experimental results indicated that photodegradation was the main transformation pathway for both ANT and PYR in multicomponent mixtures. The amount of the PAHs volatilizing from the leaf surfaces and entering the inner leaf tissues was negligible. Over a certain period of irradiation time, the photodegradation of both PYR and ANT adsorbed onto the leaves of Ac and Ko followed first-order kinetics, with faster rates being observed on Ac leaves. In addition, the photodegradation rate of PYR on the leaves of the mangrove species in multicomponent mixtures was much slower than that of adsorbed ANT. Compared with the PAHs adsorbed as single component, the photodegradation rate of ANT adsorbed in multicomponent mixtures was slower, while that of PYR was faster. Moreover, the photodegradation of PYR and ANT dissolved in water in multicomponent mixtures was investigated for comparison. The photodegradation rate on leaves was much slower than in water. Therefore, the physical-chemical properties of the substrate may strongly influence the photodegradation rate of adsorbed PAHs.

Age-Related Differences in Spatiotemporal Variables and Ground Reaction Forces During Sprinting in Boys.

PubMed

Nagahara, Ryu; Takai, Yohei; Haramura, Miki; Mizutani, Mirai; Matsuo, Akifumi; Kanehisa, Hiroaki; Fukunaga, Tetsuo

2018-02-24

We aimed to elucidate age-related differences in spatiotemporal and ground reaction force variables during sprinting in boys over a broad range of chronological ages. Ground reaction force signals during 50-m sprinting were recorded in 99 boys aged 6.5-15.4 years. Step-to-step spatiotemporal variables and mean forces were then calculated. There was a slower rate of development in sprinting performance in the age span from 8.8 to 12.1 years compared with younger and older boys. During that age span, mean propulsive force was almost constant, and step frequency for older boys was lower regardless of sprinting phase. During the ages younger than 8.8 years and older than 12.1 years, sprint performance rapidly increased with increasing mean propulsive forces during the middle acceleration and maximal speed phases and during the initial acceleration phase. There was a stage of temporal slower development of sprinting ability from age 8.8 to 12.1 years, being characterized by unchanged propulsive force and decreased step frequency. Moreover, increasing propulsive forces during the middle acceleration and maximal speed phases and during the initial acceleration phase are probably responsible for the rapid development of sprinting ability before and after the period of temporal slower development of sprinting ability.

Direct Observation of the Photodegradation of Anthracene and Pyrene Adsorbed onto Mangrove Leaves

PubMed Central

Wang, Ping; Wu, Tun-Hua; Zhang, Yong

2014-01-01

An established synchronous fluorimetry method was used for in situ investigation of the photodegradation of pyrene (PYR) and anthracene (ANT) adsorbed onto fresh leaves of the seedlings of two mangrove species, Aegiceras corniculatum (L.) Blanco (Ac) and Kandelia obovata (Ko) in multicomponent mixtures (mixture of the ANT and PYR). Experimental results indicated that photodegradation was the main transformation pathway for both ANT and PYR in multicomponent mixtures. The amount of the PAHs volatilizing from the leaf surfaces and entering the inner leaf tissues was negligible. Over a certain period of irradiation time, the photodegradation of both PYR and ANT adsorbed onto the leaves of Ac and Ko followed first-order kinetics, with faster rates being observed on Ac leaves. In addition, the photodegradation rate of PYR on the leaves of the mangrove species in multicomponent mixtures was much slower than that of adsorbed ANT. Compared with the PAHs adsorbed as single component, the photodegradation rate of ANT adsorbed in multicomponent mixtures was slower, while that of PYR was faster. Moreover, the photodegradation of PYR and ANT dissolved in water in multicomponent mixtures was investigated for comparison. The photodegradation rate on leaves was much slower than in water. Therefore, the physical-chemical properties of the substrate may strongly influence the photodegradation rate of adsorbed PAHs. PMID:25144741

RLV-TD Flight Measured Aeroacoustic Levels and its Comparison with Predictions

NASA Astrophysics Data System (ADS)

Manokaran, K.; Prasath, M.; Venkata Subrahmanyam, B.; Ganesan, V. R.; Ravindran, Archana; Babu, C.

2017-12-01

The Reusable Launch Vehicle-Technology Demonstrator (RLV-TD) is a wing body configuration successfully flight tested. One of the important flight measurements is the acoustic levels. There were five external microphones, mounted on the fuselage-forebody, wing, vertical tail, inter-stage (ITS) and core base shroud to measure the acoustic levels from lift-off to splash down. In the ascent phase, core base shroud recorded the overall maximum at both lift-off and transonic conditions. In-flight noise levels measured on the wing is second highest, followed by fuselage and vertical tail. Predictions for flight trajectory compare well at all locations except for vertical tail (4.5 dB). In the descent phase, maximum measured OASPL occurs at transonic condition for the wing, followed by vertical tail and fuselage. Predictions for flight trajectory compare well at all locations except for wing (- 6.0 dB). Spectrum comparison is good in the ascent phase compared to descent phase. Roll Reaction control system (RCS) thruster firing signature is seen in the acoustic measurements on the wing and vertical tail during lift-off.

Bird Flight as a Model for a Course in Unsteady Aerodynamics

NASA Astrophysics Data System (ADS)

Jacob, Jamey; Mitchell, Jonathan; Puopolo, Michael

2014-11-01

Traditional unsteady aerodynamics courses at the graduate level focus on theoretical formulations of oscillating airfoil behavior. Aerodynamics students with a vision for understanding bird-flight and small unmanned aircraft dynamics desire to move beyond traditional flow models towards new and creative ways of appreciating the motion of agile flight systems. High-speed videos are used to record kinematics of bird flight, particularly barred owls and red-shouldered hawks during perching maneuvers, and compared with model aircraft performing similar maneuvers. Development of a perching glider and associated control laws to model the dynamics are used as a class project. Observations are used to determine what different species and sizes of birds share in their methods to approach a perch under similar conditions. Using fundamental flight dynamics, simplified models capable of predicting position, attitude, and velocity of the flier are developed and compared with the observations. By comparing the measured data from the videos and predicted and measured motions from the glider models, it is hoped that the students gain a better understanding of the complexity of unsteady aerodynamics and aeronautics and an appreciation for the beauty of avian flight.

Investigation of the flight mechanics simulation of a hovering helicopter

NASA Technical Reports Server (NTRS)

Chaimovich, M.; Rosen, A.; Rand, O.; Mansur, M. H.; Tischler, M. B.

1992-01-01

The flight mechanics simulation of a hovering helicopter is investigated by comparing the results of two different numerical models with flight test data for a hovering AH-64 Apache. The two models are the U.S. Army BEMAP and the Technion model. These nonlinear models are linearized by applying a numerical linearization procedure. The results of the linear models are compared with identification results in terms of eigenvalues, stability and control derivatives, and frequency responses. Detailed time histories of the responses of the complete nonlinear models, as a result of various pilots' inputs, are compared with flight test results. In addition the sensitivity of the models to various effects are also investigated. The results are discussed and problematic aspects of the simulation are identified.

Orthostatic Intolerance and Motion Sickness After Parabolic Flight

NASA Technical Reports Server (NTRS)

Schlegel, Todd T.; Brown, Troy E.; Wood, Scott J.; Benavides, Edgar W.; Bondar, Roberta L.; Stein, Flo; Moradshahi, Peyman; Harm, Deborah L.; Low, Phillip A.

1999-01-01

Orthostatic intolerance is common in astronauts after prolonged space flight. However, the "push-pull effect" in military aviators suggests that brief exposures to transitions between hypo- and hypergravity are sufficient to induce untoward autonomic cardiovascular physiology in susceptible individuals. We therefore investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy test subjects before and after a seated 2-hr parabolic flight. At the same time, we also investigated relationships between parabolic flight-induced vomiting and changes in orthostatic and autonomic cardiovascular function. After parabolic flight, 8 of 16 subjects could not tolerate a 30-min upright tilt test, compared to 2 of 16 before flight. Whereas new intolerance in non-Vomiters resembled the clinical postural tachycardia syndrome (POTS), new intolerance in Vomiters was characterized by comparatively isolated upright hypocapnia and cerebral vasoconstriction. As a group, Vomiters also had evidence for increased postflight fluctuations in efferent vagal-cardiac nerve traffic occurring independently of any superimposed change in respiration. Results suggest that syndromes of orthostatic intolerance resembling those occurring after space flight can occur after a brief (i.e., 2-hr) parabolic flight.

Identification of pilot dynamics from in-flight tracking data

NASA Technical Reports Server (NTRS)

Hess, R. A.; Mnich, M. A.

1985-01-01

Data from a representative flight task involving an F-14 'pursuer' aircraft tracking a T-38 'target' aircraft in a 3G wind-up turn and in level flight are processed using a least squares identification technique in an attempt to identify pilot/vehicle dynamics. Comparative identification results are provided by a Fourier coefficient method which requires a carefully designed and implemented input consisting of a sum of sinusoids. The least-squares results compare favorably with those obtained by the Fourier technique. An example of crossover frequency regression is discussed in the light of the conditions of one of the flight configurations.

Rodent growth, behavior, and physiology resulting from flight on the Space Life Sciences-1 mission

NASA Technical Reports Server (NTRS)

Jahns, G.; Meylor, J.; Fast, T.; Hawes, N.; Zarow, G.

1992-01-01

A rodent-based spaceflight study is conducted to investigate physiological changes in rats vs humans and the effects of changes in the design of the Research Animal Holding Facility (RAHF) and the Animal Enclosure Module (AEM). Rats were housed in the AEM and the RAHF, and controls were kept in identical flight hardware on earth subjected to the same flight-environmental profile. Biosamples and organ weights are taken to compare the rats before and after flight, and food/water intake are also compared. Weight gain, body weight, and food consumptions in the flight rats are significantly lower than corresponding values for the control subjects. Flight rats tend to have smaller postexperiment spleens and hearts, and flight rats consumed more water in the AEM than in the RAHF. The rodents' behavior is analogous to humans with respect to physiological and reconditioning effects, showing that the rat is a good model for basic research into the effects of spaceflight on humans.

Development and evaluation of an airplane electronic display format aligned with the inertial velocity vector

NASA Technical Reports Server (NTRS)

Steinmetz, G. G.

1986-01-01

The development of an electronic primary flight display format aligned with the aircraft velocity vector, a simulation evaluation comparing this format with an electronic attitude-aligned primary flight display format, and a flight evaluation of the velocity-vector-aligned display format are described. Earlier tests in turbulent conditions with the electronic attitude-aligned display format had exhibited unsteadiness. A primary objective of aligning the display format with the velocity vector was to take advantage of a velocity-vector control-wheel steering system to provide steadiness of display during turbulent conditions. Better situational awareness under crosswind conditions was also achieved. The evaluation task was a curved, descending approach with turbulent and crosswind conditions. Primary flight display formats contained computer-drawn perspective runway images and flight-path angle information. The flight tests were conducted aboard the NASA Transport Systems Research Vehicle (TSRV). Comparative results of the simulation and flight tests were principally obtained from subjective commentary. Overall, the pilots preferred the display format aligned with the velocity vector.

Aerodynamic Parameter Estimation for the X-43A (Hyper-X) from Flight Data

NASA Technical Reports Server (NTRS)

Morelli, Eugene A.; Derry, Stephen D.; Smith, Mark S.

2005-01-01

Aerodynamic parameters were estimated based on flight data from the third flight of the X-43A hypersonic research vehicle, also called Hyper-X. Maneuvers were flown using multiple orthogonal phase-optimized sweep inputs applied as simultaneous control surface perturbations at Mach 8, 7, 6, 5, 4, and 3 during the vehicle descent. Aerodynamic parameters, consisting of non-dimensional longitudinal and lateral stability and control derivatives, were estimated from flight data at each Mach number. Multi-step inputs at nearly the same flight conditions were also flown to assess the prediction capability of the identified models. Prediction errors were found to be comparable in magnitude to the modeling errors, which indicates accurate modeling. Aerodynamic parameter estimates were plotted as a function of Mach number, and compared with estimates from the pre-flight aerodynamic database, which was based on wind-tunnel tests and computational fluid dynamics. Agreement between flight estimates and values computed from the aerodynamic database was excellent overall.

Effects of Walking Speed and Visual-Target Distance on Toe Trajectory During Swing Phase

NASA Technical Reports Server (NTRS)

Miller, Chris; Peters, Brian; Brady, Rachel; Warren, Liz; Richards, Jason; Mulavara, Ajitkumar; Sung, Hsi-Guang; Bloomberg, Jacob

2006-01-01

After spaceflight, astronauts experience disturbances in their ability to walk and maintain postural stability (Bloomberg, et al., 1997). One of the post-flight neurovestibular assessments requires that the astronaut walk on a treadmill at 1.8 m/sec (4.0 mph), while performing a visual acuity test, set at two different distances ( far and near ). For the first few days after landing, some crewmembers can not maintain the required pace, so a lower speed may be used. The slower velocity must be considered in the kinematic analysis, because Andriacchi, et al. (1977) showed that in clinical populations, changes in gait parameters may be attributable more to slower gait speed than pathology. Studying toe trajectory gives a global view of control of the leg, since it involves coordination of muscles and joints in both the swing and stance legs (Karst, et al., 1999). Winter (1992) and Murray, et al. (1984) reported that toe clearance during overground walking increased slightly as speed increased, but not significantly. Also, toe vertical peaks in both early and late swing phase did increase significantly with increasing speed. During conventional testing of overground locomotion, subjects are usually asked to fix their gaze on the end of the walkway a far target. But target (i.e., visual fixation) distance has been shown to affect head and trunk motion during treadmill walking (Bloomberg, et al., 1992; Peters, et al., in review). Since the head and trunk can not maintain stable gaze without proper coordination with the lower body (Mulavara & Bloomberg, 2003), it would stand to reason that lower body kinematics may be altered as well when target distance is modified. The purpose of this study was to determine changes in toe vertical trajectory during treadmill walking due to changes in walking speed and target distance.

Relationship between National Institutes of Health research awards to US medical schools and managed care market penetration.

PubMed

Moy, E; Mazzaschi, A J; Levin, R J; Blake, D A; Griner, P F

1997-07-16

Medical research conducted in academic medical centers is often dependent on support from clinical revenues generated in these institutions. Anecdotal evidence suggests that managed care has the potential to affect research conducted in academic medical centers by challenging these clinical revenues. To examine whether empirical evidence supports a relationship between managed care and the ability of US medical schools to sustain biomedical research. Data on annual extramural research grants awarded to US medical schools by the National Institutes of Health (NIH) from fiscal years 1986 to 1995 were obtained, and each medical school was matched to a market for which information about health maintenance organization (HMO) penetration in 1995 was available. Growth in total NIH awards, traditional research project (R01) awards, R01 awards to clinical and basic science departments, and changes in institutional ranking by NIH awards were compared among schools located in markets with low, medium, and high managed care penetration. Medical schools in all markets had comparable rates of growth in NIH awards from 1986 to 1990. Thereafter, medical schools in markets with high managed care penetration had slower growth in the dollar amounts and numbers of NIH awards compared with schools in markets with low or medium managed care penetration. This slower growth for schools in high managed care markets was associated with loss of share of NIH awards, equal to $98 million in 1995, and lower institutional ranking by NIH awards. Much of this revenue loss can be explained by the slower growth of R01 awards to clinical departments in medical schools in high managed care markets. These findings provide evidence of an inverse relationship between growth in NIH awards during the past decade and managed care penetration among US medical schools. Whether this association is causal remains to be determined.

Slower saccadic reading in Parkinson’s disease

PubMed Central

Jehangir, Naz; Yu, Caroline Yizhu; Song, Jeehey; Shariati, Mohammad Ali; Binder, Steven; Beyer, Jill; Santini, Veronica; Poston, Kathleen

2018-01-01

Idiopathic Parkinson’s Disease (PD) is characterized by degeneration of dopaminergic and other neurons, leading to motor and non-motor deficits. Abnormal eye movements in PD, including fixations, saccades, and convergence, are well described. However, saccadic reading, which requires serial and alternating saccades and fixations, is not well studied, despite its obvious impact on the quality of life. In this study, we assessed saccadic reading using variations of the King-Devick (KD) test, a rapid single digit number naming test, as a way to assess the ability to make serial left-to-right ocular motor movements necessary for reading. We recruited 42 treated PD patients and 80 age-matched controls and compared their reading times with a variety of measures, including age, duration of disease, Unified Parkinson’s Disease Rating Scale (UPDRS), the National Eye Institute 25-Item Visual Functioning Questionnaire 25 (VFQ-25), and Montreal Cognitive assessment (MoCA) test. The subjects performed 4 trials of reading 120 single digit numbers aloud as fast as possible without making errors. In each trial, they read 3 pages (KD1, KD2, and KD3), and each page contained 40 numbers per page in 8 lines with 5 numbers/line. We found that PD patients read about 20% slower than controls on all tests (KD1, 2, and 3 tests) (p < 0.02), and both groups read irregularly spaced numbers slower than regularly spaced numbers. Having lines between numbers to guide reading (KD1 tests) did not impact reading time in both PD and controls, but increased visual crowding as a result of decreased spacing between numbers (KD3 tests) was associated with significantly slower reading times in both PD and control groups. Our study revealed that saccadic reading is slower in PD, but controls and PD patients are both impacted by visuospatial planning challenges posed by increased visual crowding and irregularity of number spacing. Reading time did not correlate with UPDRS or MoCA scores in PD patients but significantly correlated with age, duration of disease, and VFQ-25 scores. The presence of convergence insufficiency did not significantly correlate with reading time in PD patients, although on average there was slower reading time in those with convergence insufficiency by 8 s (p = 0.2613). We propose that a simple reading task using 120 single-digit numbers can be used as a screening tool in the clinical setting to assess functional ocular motor difficulties in Parkinson’s disease that can have a profound impact on quality of life. PMID:29364897

Slower saccadic reading in Parkinson's disease.

PubMed

Jehangir, Naz; Yu, Caroline Yizhu; Song, Jeehey; Shariati, Mohammad Ali; Binder, Steven; Beyer, Jill; Santini, Veronica; Poston, Kathleen; Liao, Yaping Joyce

2018-01-01

Idiopathic Parkinson's Disease (PD) is characterized by degeneration of dopaminergic and other neurons, leading to motor and non-motor deficits. Abnormal eye movements in PD, including fixations, saccades, and convergence, are well described. However, saccadic reading, which requires serial and alternating saccades and fixations, is not well studied, despite its obvious impact on the quality of life. In this study, we assessed saccadic reading using variations of the King-Devick (KD) test, a rapid single digit number naming test, as a way to assess the ability to make serial left-to-right ocular motor movements necessary for reading. We recruited 42 treated PD patients and 80 age-matched controls and compared their reading times with a variety of measures, including age, duration of disease, Unified Parkinson's Disease Rating Scale (UPDRS), the National Eye Institute 25-Item Visual Functioning Questionnaire 25 (VFQ-25), and Montreal Cognitive assessment (MoCA) test. The subjects performed 4 trials of reading 120 single digit numbers aloud as fast as possible without making errors. In each trial, they read 3 pages (KD1, KD2, and KD3), and each page contained 40 numbers per page in 8 lines with 5 numbers/line. We found that PD patients read about 20% slower than controls on all tests (KD1, 2, and 3 tests) (p < 0.02), and both groups read irregularly spaced numbers slower than regularly spaced numbers. Having lines between numbers to guide reading (KD1 tests) did not impact reading time in both PD and controls, but increased visual crowding as a result of decreased spacing between numbers (KD3 tests) was associated with significantly slower reading times in both PD and control groups. Our study revealed that saccadic reading is slower in PD, but controls and PD patients are both impacted by visuospatial planning challenges posed by increased visual crowding and irregularity of number spacing. Reading time did not correlate with UPDRS or MoCA scores in PD patients but significantly correlated with age, duration of disease, and VFQ-25 scores. The presence of convergence insufficiency did not significantly correlate with reading time in PD patients, although on average there was slower reading time in those with convergence insufficiency by 8 s (p = 0.2613). We propose that a simple reading task using 120 single-digit numbers can be used as a screening tool in the clinical setting to assess functional ocular motor difficulties in Parkinson's disease that can have a profound impact on quality of life.

In-flight hypoxia events in tactical jet aviation: characteristics compared to normobaric training.

PubMed

Deussing, Eric C; Artino, Anthony R; Folga, Richard V

2011-08-01

Hypoxia continues to be a significant threat in military aviation. In an attempt to counter the hypoxia threat, military jet aviators receive periodic training using a reduced oxygen breathing device (ROBD). This study explored the characteristics of in-flight hypoxia events among tactical jet aviators and compared reported symptoms to those experienced during ROBD training. An anonymous survey was administered to naval aviators prior to aviation physiology training. The survey queried them about previous in-flight hypoxia encounters and the symptoms they experienced. These data were then compared to symptom data from a previous ROBD training survey using Chi-square analyses. Of the 566 aviators who completed the survey, 112 (20%) reported experiencing hypoxia symptoms in a tactical jet aircraft and 64 aviators (57%) indicated they were not wearing the required oxygen mask when the incident first occurred. The results also revealed only 21% of hypoxia events were reported in aviation hazard reports and the three most commonly recorded in-flight hypoxia symptoms were tingling (54%), difficulty concentrating (32%), and dizziness (30%). Chi-square analyses revealed statistically significant differences in frequency of reporting between 5 of 16 symptoms encountered in flight compared to ROBD training. The present investigation is the first survey-based study of hypoxia events in U.S. naval aviation. The study reveals in-flight, mask-on hypoxia has a similar overall reported symptom profile to ROBD training. Further, results suggest increased oxygen-mask compliance among these aviators may be necessary to effectively combat in-flight hypoxia.

Comparison of ground-based and space flight energy expenditure and water turnover in middle-aged healthy male US astronauts

NASA Technical Reports Server (NTRS)

Lane, H. W.; Gretebeck, R. J.; Schoeller, D. A.; Davis-Street, J.; Socki, R. A.; Gibson, E. K.

1997-01-01

Energy requirements during space flight are poorly defined because they depend on metabolic-balance studies, food disappearance, and dietary records. Water turnover has been estimated by balance methods only. The purpose of this study was to determine energy requirements and water turnover for short-term space flights (8-14 d). Subjects were 13 male astronauts aged 36-51 y with normal body mass indexes (BMIs). Total energy expenditure (TEE) was determined during both a ground-based period and space flight and compared with the World Health Organization (WHO) calculations of energy requirements and dietary intake. TEE was not different for the ground-based and the space-flight periods (12.40 +/- 2.83 and 11.70 +/- 1.89 MJ/d, respectively), and the WHO calculation using the moderate activity correction was a good predictor of TEE during space flight. During the ground-based period, energy intake and TEE did not differ, but during space flight energy intake was significantly lower than TEE; body weight was also less at landing than before flight. Water turnover was lower during space flight than during the ground-based period (2.7 +/- 0.6 compared with 3.8 +/- 0.5 L/d), probably because of lower fluid intakes and perspiration loss during flight. This study confirmed that the WHO calculation can be used for male crew members' energy requirements during short space flights.

Estimating the health consequences of flight attendant work: comparing flight attendant health to the general population in a cross-sectional study.

PubMed

McNeely, Eileen; Mordukhovich, Irina; Tideman, Samuel; Gale, Sara; Coull, Brent

2018-03-23

Flight attendants are an understudied occupational group, despite undergoing a wide and unique range of adverse job-related exposures. In our study, we aimed to characterize the health profile of cabin crew relative to the U.S. general population. In 2014-2015, we surveyed participants of the Harvard Flight Attendant Health Study. We compared the prevalence of their health conditions to a contemporaneous cohort in the National Health and Nutrition Examination Survey (NHANES 2013-2014) using age-weighted standardized prevalence ratios (SPRs). We also analyzed associations between job tenure and selected health outcomes, using logistic regression and adjusting for potential confounders. Compared to the NHANES population (n = 2729), flight attendants (n = 5366) had a higher prevalence of female reproductive cancers (SPR = 1.66, 95% CI: 1.18-2.33), cancers at all sites (SPR = 2.15, 95% CI: 1.73-2.67 among females), as well as sleep disorders, fatigue, and depression, with SPRs ranging between 1.98 and 5.57 depending on gender and the specific condition examined. In contrast, we observed a decreased prevalence of cardiac and respiratory outcomes among flight crew relative to NHANES. Health conditions that increased with longer job tenure were sleep disorders, anxiety/depression, alcohol abuse, any cancer, peripheral artery disease, sinusitis, foot surgery, infertility, and several perinatal outcomes. We observed higher rates of specific adverse health outcomes in U.S. flight attendants compared to the general population, as well as associations between longer tenure and health conditions, which should be interpreted in light of recall bias and a cross-sectional design. Future longitudinal studies should evaluate specific exposure-disease associations among flight crew.

Effects of space flight and IGF-1 on immune function

NASA Astrophysics Data System (ADS)

1999-01-01

We tested the hypothesis that insulin-like growth factor-1 (IGF-1) would ameliorate space flight-induced effects on the immune system. Twelve male, Sprague-Dawley rats, surgically implanted with mini osmotic pumps, were subjected to space flight for 10 days on STS-77. Six rats received 10 mg/kg/day of IGF-1 and 6 rats received saline. Flight animals had a lymphocytopenia and granulocytosis which were reversed by IGF-1. Flight animals had significantly higher corticosterone levels than ground controls but IGF-1 did not impact this stress hormone. Therefore, the reversed granulocytosis did not correlate with serum corticosterone. Space flight and IGF-1 also combined to induce a monocytopenia that was not evident in ground control animals treated with IGF-1 or in animals subjected to space flight but given physiological saline. There was a significant increase in spleen weights in vivarium animals treated with IGF-1, however, this change did not occur in flight animals. We observed reduced agonist-induced lymph node cell proliferation by cells from flight animals compared to ground controls. The reduced proliferation was not augmented by IGF-1 treatment. There was enhanced secretion of TNF, IL-6 and NO by flight-animal peritoneal macrophages compared to vivarium controls, however, O2- secretion was not affected. These data suggest that IGF-1 can ameliorate some of the effects of space flight but that space flight can also impact the normal response to IGF-1.

Association of fall history with the Timed Up and Go test score and the dual task cost: A cross-sectional study among independent community-dwelling older adults.

PubMed

Asai, Tsuyoshi; Oshima, Kensuke; Fukumoto, Yoshihiro; Yonezawa, Yuri; Matsuo, Asuka; Misu, Shogo

2018-05-21

To investigate the associations between fall history and the Timed Up and Go (TUG) test (single-TUG test), TUG test while counting aloud backwards from 100 (dual-TUG test) and the dual-task cost (DTC) among independent community-dwelling older adults. This cross-sectional study included 537 older adults who lived independently in the community. Data on fall history in the previous year were obtained by self-administrated questionnaire. The single- and dual-TUG tests were carried out, and the DTC value was computed from these results. Associations between fall history and these TUG-related values were analyzed using multivariate logistic regression models. The participants were divided into fall risk groups using the cut-off values of those significantly associated with falling, and the odds ratios (OR) were computed. Slower single-TUG test scores and lower DTC values were significantly associated with fall history after adjusting for potential confounders (single-TUG test score: OR 1.133, 95% CI 1.029-1.249; DTC value: OR 0.984, 95% CI 0.968-0.998). Older adults with slower single-TUG test scores and lower DTC values reported a fall history more often than those in other categories (OR compared with the lower-risk single-TUG and lower-risk DTC groups: 3.474, 95% CI 1.881-6.570). Slower single-TUG test scores and lower DTC values are associated with fall history among independent community-dwelling older adults. To some extent, dual task performance might provide added value for fall assessment, compared with administering the TUG test alone. Geriatr Gerontol Int 2018; ••: ••-••. © 2018 Japan Geriatrics Society.

Dopaminergic modulation of arm swing during gait among Parkinson’s disease patients

PubMed Central

Sterling, Nicholas W.; Cusumano, Joseph P.; Shaham, Noam; Piazza, Stephen J.; Liu, Guodong; Kong, Lan; Du, Guangwei; Lewis, Mechelle M.; Huang, Xuemei

2015-01-01

Background Reduced arm swing amplitude, symmetry, and coordination during gait have been reported in Parkinson’s disease (PD), but the relationship between dopaminergic depletion and these upper limb gait changes remains unclear. This study investigated the effects of dopaminergic drugs on arm swing velocity, symmetry, and coordination in PD. Methods Forearm angular velocity was recorded in 16 PD and 17 control subjects (Controls) during free walking trials. Angular velocity amplitude of each arm, arm swing asymmetry, and maximum cross-correlation were compared between control and PD groups, and between OFF- and ON-medication states among PD subjects. Results Compared to Controls, PD subjects in the OFF-medication state exhibited lower angular velocity amplitude of the slower- (p=0.0018), but not faster- (p=0.2801) swinging arm. In addition, PD subjects demonstrated increased arm swing asymmetry (p=0.0046) and lower maximum cross-correlation (p=0.0026). Following dopaminergic treatment, angular velocity amplitude increased in the slower- (p=0.0182), but not faster- (p=0.2312) swinging arm among PD subjects. Furthermore, arm swing asymmetry decreased (p=0.0386), whereas maximum cross-correlation showed no change (p=0.7436). Pre-drug angular velocity amplitude of the slower-swinging arm was correlated inversely with the change in arm swing asymmetry (R=−0.73824, p=0.0011). Conclusions This study provides quantitative evidence that reduced arm swing and symmetry in PD can be modulated by dopaminergic replacement. The lack of modulations of bilateral arm coordination suggests that additional neurotransmitters may also be involved in arm swing changes in PD. Further studies are warranted to investigate the longitudinal trajectory of arm swing dynamics throughout PD progression. PMID:25502948

Dopaminergic modulation of arm swing during gait among Parkinson's disease patients.

PubMed

Sterling, Nicholas W; Cusumano, Joseph P; Shaham, Noam; Piazza, Stephen J; Liu, Guodong; Kong, Lan; Du, Guangwei; Lewis, Mechelle M; Huang, Xuemei

2015-01-01

Reduced arm swing amplitude, symmetry, and coordination during gait have been reported in Parkinson's disease (PD), but the relationship between dopaminergic depletion and these upper limb gait changes remains unclear. We aimed to investigate the effects of dopaminergic drugs on arm swing velocity, symmetry, and coordination in PD. Forearm angular velocity was recorded in 16 PD and 17 control subjects (Controls) during free walking trials. Angular velocity amplitude of each arm, arm swing asymmetry, and maximum cross-correlation were compared between control and PD groups, and between OFF- and ON-medication states among PD subjects. Compared to Controls, PD subjects in the OFF-medication state exhibited lower angular velocity amplitude of the slower- (p = 0.0018), but not faster- (p = 0.2801) swinging arm. In addition, PD subjects demonstrated increased arm swing asymmetry (p = 0.0046) and lower maximum cross-correlation (p = 0.0026). Following dopaminergic treatment, angular velocity amplitude increased in the slower- (p = 0.0182), but not faster- (p = 0.2312) swinging arm among PD subjects. Furthermore, arm swing asymmetry decreased (p = 0.0386), whereas maximum cross-correlation showed no change (p = 0.7436). Pre-drug angular velocity amplitude of the slower-swinging arm was correlated inversely with the change in arm swing asymmetry (R = -0.73824, p = 0.0011). This study provides quantitative evidence that reduced arm swing and symmetry in PD can be modulated by dopaminergic replacement. The lack of modulations of bilateral arm coordination suggests that additional neurotransmitters may also be involved in arm swing changes in PD. Further studies are warranted to investigate the longitudinal trajectory of arm swing dynamics throughout PD progression.

Time for a strategy in night-time dopaminergic therapy? An objective sensor-based analysis of nocturnal hypokinesia and sleeping positions in Parkinson's disease.

PubMed

Sringean, Jirada; Anan, Chanawat; Thanawattano, Chusak; Bhidayasiri, Roongroj

2017-02-15

Nocturnal hypokinesia is a common night-time symptom in patients with Parkinson's disease (PD). However, there is still little understanding of the nature, and variations of severity of this symptom. To evaluate the severity of nocturnal hypokinesia and sleep positions in PD patients using multisite wearable sensors. Nocturnal parameters and sleep positions in 18 PD couples were assessed and compared using wearable sensors (limbs and trunk) for one night in their homes. Nocturnal parameters included number, velocity, acceleration, degree, limb movements and the number of times they got out of bed. PD patients had significantly fewer episodes of turns in bed than their spouses (p=0.043), which was associated with significantly slower speed (p=0.005), acceleration (p=0.005) and fewer degrees (p=0.017). When we split the night into the first and second half, significant findings were mainly demonstrated in the second half of the night, including significantly fewer turns (p=0.02) with smaller degrees (p=0.017), slower speed (p=0.005) and acceleration (p=0.007). No significant differences in these parameters were shown in the first half of the night except for smaller degrees of turn in bed in PD patients (p=0.028) and slower acceleration (p=0.037). In addition, PD patients spent significantly more time in a supine position compared to their spouses (p=0.031) with significantly less time in a prone position (p=0.041). Nocturnal hypokinesia gets worse as the night progresses. Treatment of nocturnal hypokinesia should aim at providing a continuous dopaminergic delivery that can achieve a sustained therapeutic level of dopamine throughout the night. Copyright © 2016 Elsevier B.V. All rights reserved.

The chemical stability of abasic RNA compared to abasic DNA

PubMed Central

Küpfer, Pascal A.; Leumann, Christian J.

2007-01-01

We describe the synthesis of an abasic RNA phosphoramidite carrying a photocleavable 1-(2-nitrophenyl)ethyl (NPE) group at the anomeric center and a triisopropylsilyloxymethyl (TOM) group as 2′-O-protecting group together with the analogous DNA and the 2′-OMe RNA abasic building blocks. These units were incorporated into RNA-, 2′-OMe-RNA- and DNA for the purpose of studying their chemical stabilities towards backbone cleavage in a comparative way. Stability measurements were performed under basic conditions (0.1 M NaOH) and in the presence of aniline (pH 4.6) at 37°C. The kinetics and mechanisms of strand cleavage were followed by High pressure liquid chromotography and ESI-MS. Under basic conditions, strand cleavage at abasic RNA sites can occur via β,δ-elimination and 2′,3′-cyclophosphate formation. We found that β,δ-elimination was 154-fold slower compared to the same mechanism in abasic DNA. Overall strand cleavage of abasic RNA (including cyclophosphate formation) was still 16.8 times slower compared to abasic DNA. In the presence of aniline at pH 4.6, where only β,δ-elimination contributes to strand cleavage, a 15-fold reduced cleavage rate at the RNA abasic site was observed. Thus abasic RNA is significantly more stable than abasic DNA. The higher stability of abasic RNA is discussed in the context of its potential biological role. PMID:17151071

Guillain-Barré syndrome in the elderly.

PubMed

Peric, Stojan; Berisavac, Ivana; Stojiljkovic Tamas, Olivera; Rajic, Sonja; Babic, Milica; Cvijanovic, Milan; Dominovic-Kovacevic, Aleksandra; Basta, Ivana; Beslac-Bumbasirevic, Ljiljana; Lavrnic, Dragana

2016-06-01

The aim of the study was to analyze specific features of Guillain-Barré syndrome (GBS) in old people. The study included 403 GBS patients (62% young [<60 years], 35% young-old [60-80 years], and 3% old-old [>80 years]). Diagnosis of GBS was made according to the National Institute of Neurological Disorders and Stroke (NINDS criteria). Severe disability (GBS disability score of >3) at nadir was more common in old compared with young patients (p = 0.0001) as was mortality (9% vs. 2%, respectively). Acute motor and sensory axonal neuropathy and hyponatremia were more common in old compared with young patients (12% vs. 6% and 27% vs. 18%, respectively, p = 0.04). A positive history for malignancy was more than three times more common in old than young patients (11% vs. 3%, respectively, p = 0.01). Disability on nadir was similar in young-old and old-old subjects with disability on discharge being more severe in old-old (p = 0.04) suggesting slower recovery in this subgroup. Bulbar symptoms were more common in old-old compared with young-old (50% vs. 19%, respectively, p = 0.01). Comorbidities were present in virtually all old-old patients compared with 66% of young-old patients (p = 0.04). In conclusion, Elderly patients, and especially old-old patients, with GBS have more severe disease with slower recovery than do younger patients. © 2016 Peripheral Nerve Society.

Differences in the Aerobic Capacity of Flight Muscles between Butterfly Populations and Species with Dissimilar Flight Abilities

PubMed Central

Rauhamäki, Virve; Wolfram, Joy; Jokitalo, Eija; Hanski, Ilkka; Dahlhoff, Elizabeth P.

2014-01-01

Habitat loss and climate change are rapidly converting natural habitats and thereby increasing the significance of dispersal capacity for vulnerable species. Flight is necessary for dispersal in many insects, and differences in dispersal capacity may reflect dissimilarities in flight muscle aerobic capacity. In a large metapopulation of the Glanville fritillary butterfly in the Åland Islands in Finland, adults disperse frequently between small local populations. Individuals found in newly established populations have higher flight metabolic rates and field-measured dispersal distances than butterflies in old populations. To assess possible differences in flight muscle aerobic capacity among Glanville fritillary populations, enzyme activities and tissue concentrations of the mitochondrial protein Cytochrome-c Oxidase (CytOx) were measured and compared with four other species of Nymphalid butterflies. Flight muscle structure and mitochondrial density were also examined in the Glanville fritillary and a long-distance migrant, the red admiral. Glanville fritillaries from new populations had significantly higher aerobic capacities than individuals from old populations. Comparing the different species, strong-flying butterfly species had higher flight muscle CytOx content and enzymatic activity than short-distance fliers, and mitochondria were larger and more numerous in the flight muscle of the red admiral than the Glanville fritillary. These results suggest that superior dispersal capacity of butterflies in new populations of the Glanville fritillary is due in part to greater aerobic capacity, though this species has a low aerobic capacity in general when compared with known strong fliers. Low aerobic capacity may limit dispersal ability of the Glanville fritillary. PMID:24416122

A Comparison of the Preferred Teaching Styles of Oklahoma Aviation Maintenance Instructors and Flight Instructors

ERIC Educational Resources Information Center

King, Deann Marie

2013-01-01

The purpose of this study was to compare the preferred teaching styles of Oklahoma aviation maintenance instructors and flight instructors. The scope of this study included maintenance instructors in CareerTech schools (Part 147 programs) and ground/flight instructors in Part 141 flight schools in Oklahoma. The methodology included administering…

The aerodynamic cost of flight in bats--comparing theory with measurement

NASA Astrophysics Data System (ADS)

von Busse, Rhea; Waldman, Rye M.; Swartz, Sharon M.; Breuer, Kenneth S.

2012-11-01

Aerodynamic theory has long been used to predict the aerodynamic power required for animal flight. However, even though the actuator disk model does not account for the flapping motion of a wing, it is used for lack of any better model. The question remains: how close are these predictions to reality? We designed a study to compare predicted aerodynamic power to measured power from the kinetic energy contained in the wake shed behind a bat flying in a wind tunnel. A high-accuracy displaced light-sheet stereo PIV system was used in the Trefftz plane to capture the wake behind four bats flown over a range of flight speeds (1-6m/s). The total power in the wake was computed from the wake vorticity and these estimates were compared with the power predicted using Pennycuick's model for bird flight as well as estimates derived from measurements of the metabolic cost of flight, previously acquired from the same individuals.

A search for solar neutrons on a long duration balloon flight

NASA Technical Reports Server (NTRS)

Koga, R.; Frye, G. M., Jr.; Owens, A.; Denehy, B. V.; Mace, O.; Thomas, J.

1985-01-01

The EOSCOR 3 detector, designed to measure the flux of solar neutrons, was flown on a long duration RACOON balloon flight from Australia during Jan. through Feb, 1983. The Circum-global flight lasted 22 days. No major solar activity occurred during the flight and thus only an upper limit to the solar flare neutrons flux is given. The atmospheric neutron response is compared with that obtained on earlier flights from Palestine, Texas.

A search for solar neutrons on a long duration balloon flight

NASA Astrophysics Data System (ADS)

Koga, R.; Frye, G. M., Jr.; Owens, A.; Denehy, B. V.; Mace, O.; Thomas, J.

1985-08-01

The EOSCOR 3 detector, designed to measure the flux of solar neutrons, was flown on a long duration RACOON balloon flight from Australia during Jan. through Feb, 1983. The Circum-global flight lasted 22 days. No major solar activity occurred during the flight and thus only an upper limit to the solar flare neutrons flux is given. The atmospheric neutron response is compared with that obtained on earlier flights from Palestine, Texas.

Deterministic Ethernet for Space Applications

NASA Astrophysics Data System (ADS)

Fidi, C.; Wolff, B.

2015-09-01

Typical spacecraft systems are distributed to be able to achieve the required reliability and availability targets of the mission. However the requirements on these systems are different for launchers, satellites, human space flight and exploration missions. Launchers require typically high reliability with very short mission times whereas satellites or space exploration missions require very high availability at very long mission times. Comparing a distributed system of launchers with satellites it shows very fast reaction times in launchers versus much slower once in satellite applications. Human space flight missions are maybe most challenging concerning reliability and availability since human lives are involved and the mission times can be very long e.g. ISS. Also the reaction times of these vehicles can get challenging during mission scenarios like landing or re-entry leading to very fast control loops. In these different applications more and more autonomous functions are required to fulfil the needs of current and future missions. This autonomously leads to new requirements with respect to increase performance, determinism, reliability and availability. On the other hand side the pressure on reducing costs of electronic components in space applications is increasing, leading to the use of more and more COTS components especially for launchers and LEO satellites. This requires a technology which is able to provide a cost competitive solution for both the high reliable and available deep-space as well as the low cost “new space” markets. Future spacecraft communication standards therefore have to be much more flexible, scalable and modular to be able to deal with these upcoming challenges. The only way to fulfill these requirements is, if they are based on open standards which are used cross industry leading to a reduction of the lifecycle costs and an increase in performance. The use of a communication network that fulfills these requirements will be essential for such spacecraft’s to allow the use in launcher, satellite, human space flight and exploration missions. Using one technology and the related infrastructure for these different applications will lead to a significant reduction of complexity and would moreover lead to significant savings in size weight and power while increasing the performance of the overall system. The paper focuses on the use of the TTEthernet technology for launchers, satellites and human spaceflight and will demonstrate the scalability of the technology for the different applications. The data used is derived from the ESA TRP 7594 on “Reliable High-Speed Data Bus/Network for Safety-Oriented Missions”.

Negative charge emission due to excimer laser bombardment of sodium trisilicate glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langford, S.C.; Jensen, L.C.; Dickinson, J.T.

We describe measurements of negative charge emission accompanying irradiation of sodium trisilicate glass (Na{sub 2}O{center dot}3SiO{sub 2}) with 248-nm excimer laser light at fluences on the order of 2 J/cm{sup 2} per pulse, i.e., at the threshold for ablative etching of the glass surface. The negative charge emission consists of a very prompt photoelectron burst coincident with the laser pulse, followed by a much slower plume of electrons and negative ions traveling with a high density cloud of positive ions, previously identified as primarily Na{sup +}. Using combinations of {bold E} and {bold B} fields in conjunction with time-of-flight methods,more » the negative ions were successfully separated from the plume and tentatively identified as O{sup {minus}}, Si{sup {minus}}, NaO{sup {minus}}, and perhaps NaSi{sup {minus}}. These negative species are probably formed by gas phase collisions in the near-surface region which result in electron attachment.« less

The Influence of Emotional State and Pictorial Cues on Perceptual Judgments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimberly R. Raddatz; Abigail Werth; Tuan Q. Tran

2007-10-01

Perspective displays (e.g., CDTI) are commonly used as decision aids in environments characterized by periods of high emotional arousal (e.g., terrain enhanced primary flight displays). However, little attention has been devoted to understanding how emotional state, independently or in conjunction with other perceptual factors (e.g., pictorial depth cues), can impact perceptual judgments. Preliminary research suggests that induced emotional state (positive or negative) adversely impacts size comparisons in perspective displays (Tran & Raddatz, 2006). This study further investigated how size comparisons are affected by emotional state and pictorial depth cues while attenuating the limitations of the Tran & Raddatz (2006) study.more » Results confirmed that observers do make slower judgments under induced emotional state. However, observers under negative emotional state showed higher sensitivity (d’) and required more evidence to respond that a size difference exists (response bias) than observers under positive emotional state. Implications for display design and human performance are discussed.« less

Effects of space flight exposure on cell growth, tumorigenicity and gene expression in cancer cells

NASA Astrophysics Data System (ADS)

Yang, Cheng; Li, Yuehui; Zhang, Zhijie; Luo, Chen; Tong, Yongqing; Zhou, Guohua; Xie, Pingli; Hu, Jinyue; Li, Guancheng

2008-12-01

It is well recognized that harsh outer space environment, consisting of microgravity and radiation, poses significant health risks for human cells. To investigate potential effects of the space environment exposure on cancer cells we examined the biological changes in Caski cells carried by the "Shen Zhou IV" spaceship. After exposure for 7 days in spaceflight, 1440 survival subclonal cell lines were established and 4 cell lines were screened. 44F10 and 17E3 were selected because of their increased cell proliferation and tumorigenesis, while 48A9 and 31F2 had slower cytological events. Experiments with cell proliferation assay, flow cytometry, soft agar assay, tumorigenesis assay and DNA microarray analysis have shown that selected cell lines presented multiple biological changes in cell morphology, cell growth, tumorigenicity and gene expression. These results suggest that space environment exposure can make significant biological impact on cancer cells and provide an entry point to find the immunological target of tumorigenesis.

KSC-2009-4421

NASA Image and Video Library

2009-08-04

CAPE CANAVERAL, Fla. –Sitting on top of the mobile launcher platform and propelled by the crawler-transporter, space shuttle Discovery rolls up Launch Pad 39A at NASA's Kennedy Space Center in Florida after a nearly 12-hour journey from the Vehicle Assembly Building. First motion out of the VAB was at 2:07 a.m. EDT Aug. 4. Rollout was delayed approximately 2 hours due to lightning in the area. The rollout was slower than usual as technicians stopped several times to clear mud from the crawler's treads and bearings caused by the waterlogged crawlerway. The drying mud of the crawlerway is evident in the foreground. Discovery's 13-day flight will deliver a new crew member and 33,000 pounds of equipment to the International Space Station. The equipment includes science and storage racks, a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill. Launch of Discovery on its STS-128 mission is targeted for late August. Photo credit: NASA/Troy Cryder

1/f oscillations in a model of moth populations oriented by diffusive pheromones

NASA Astrophysics Data System (ADS)

Barbosa, L. A.; Martins, M. L.; Lima, E. R.

2005-01-01

An individual-based model for the population dynamics of Spodoptera frugiperda in a homogeneous environment is proposed. The model involves moths feeding plants, mating through an anemotaxis search (i.e., oriented by odor dispersed in a current of air), and dying due to resource competition or at a maximum age. As observed in the laboratory, the females release pheromones at exponentially distributed time intervals, and it is assumed that the ranges of the male flights follow a power-law distribution. Computer simulations of the model reveal the central role of anemotaxis search for the persistence of moth population. Such stationary populations are exponentially distributed in age, exhibit random temporal fluctuations with 1/f spectrum, and self-organize in disordered spatial patterns with long-range correlations. In addition, the model results demonstrate that pest control through pheromone mass trapping is effective only if the amounts of pheromone released by the traps decay much slower than the exponential distribution for calling female.

Meta-Analysis of Single-Case Research Design Studies on Instructional Pacing.

PubMed

Tincani, Matt; De Mers, Marilyn

2016-11-01

More than four decades of research on instructional pacing has yielded varying and, in some cases, conflicting findings. The purpose of this meta-analysis was to synthesize single-case research design (SCRD) studies on instructional pacing to determine the relative benefits of brisker or slower pacing. Participants were children and youth with and without disabilities in educational settings, excluding higher education. Tau-U, a non-parametric statistic for analyzing data in SCRD studies, was used to determine effect size estimates. The article extraction yielded 13 instructional pacing studies meeting contemporary standards for high quality SCRD research. Eleven of the 13 studies reported small to large magnitude effects when two or more pacing parameters were compared, suggesting that instructional pacing is a robust instructional variable. Brisker instructional pacing with brief inter-trial interval (ITI) produced small increases in correct responding and medium to large reductions in challenging behavior compared with extended ITI. Slower instructional pacing with extended wait-time produced small increases in correct responding, but also produced small increases in challenging behavior compared with brief wait-time. Neither brief ITI nor extended wait-time meets recently established thresholds for evidence-based practice, highlighting the need for further instructional pacing research. © The Author(s) 2016.

Developmental hearing loss impedes auditory task learning and performance in gerbils

PubMed Central

von Trapp, Gardiner; Aloni, Ishita; Young, Stephen; Semple, Malcolm N.; Sanes, Dan H.

2016-01-01

The consequences of developmental hearing loss have been reported to include both sensory and cognitive deficits. To investigate these issues in a non-human model, auditory learning and asymptotic psychometric performance were compared between normal hearing (NH) adult gerbils and those reared with conductive hearing loss (CHL). At postnatal day 10, before ear canal opening, gerbil pups underwent bilateral malleus removal to induce a permanent CHL. Both CHL and control animals were trained to approach a water spout upon presentation of a target (Go stimuli), and withhold for foils (Nogo stimuli). To assess the rate of task acquisition and asymptotic performance, animals were tested on an amplitude modulation (AM) rate discrimination task. Behavioral performance was calculated using a signal detection theory framework. Animals reared with developmental CHL displayed a slower rate of task acquisition for AM discrimination task. Slower acquisition was explained by an impaired ability to generalize to newly introduced stimuli, as compared to controls. Measurement of discrimination thresholds across consecutive testing blocks revealed that CHL animals required a greater number of testing sessions to reach asymptotic threshold values, as compared to controls. However, with sufficient training, CHL animals approached control performance. These results indicate that a sensory impediment can delay auditory learning, and increase the risk of poor performance on a temporal task. PMID:27746215

Prosody in Infant-Directed Speech Is Similar across Western and Traditional Cultures

ERIC Educational Resources Information Center

Broesch, Tanya L.; Bryant, Gregory A.

2015-01-01

When speaking to infants, adults typically alter the acoustic properties of their speech in a variety of ways compared with how they speak to other adults; for example, they use higher pitch, increased pitch range, more pitch variability, and slower speech rate. Research shows that these vocal changes happen similarly across industrialized…

Length Effects in Pseudo-Word Spelling: Stronger in Dyslexic than in Non-Dyslexic Students

ERIC Educational Resources Information Center

Juul, Holger; Petersen, Dorthe Klint

2017-01-01

It is often discussed whether dyslexics show a deviant pattern of reading and spelling development when compared to typically developing students, or whether they follow the same pattern as other students, only at markedly slower rate. The present cross-sectional study investigated phonological encoding skills in dyslexic Danish students. We…

The microbiome, intestinal function, and arginine metabolism of healthy Indian women are different from those of American and Jamaican women

USDA-ARS?s Scientific Manuscript database

Indian women have slower arginine flux during pregnancy compared with American and Jamaican women. Arginine is a semi-essential amino acid that becomes essential during periods of rapid lean tissue deposition. It is synthesized only from citrulline, a nondietary amino acid produced mainly in the gut...

Sensitization and Habituation of Motivated Behavior in Overweight and Non-Overweight Children

ERIC Educational Resources Information Center

Epstein, Leonard H.; Robinson, Jodie L.; Temple, Jennifer L.; Roemmich, James N.; Marusewski, Angela; Nadbrzuch, Rachel

2008-01-01

The rate of habituation to food is inversely related to energy intake, and overweight children may habituate slower to food and consume more energy. This study compared patterns of sensitization, as defined by an initial increase in operant or motivated responding for food, and habituation, defined by gradual reduction in responding, for macaroni…

Transition from Sensorimotor Stage 5 to Stage 6 by Down Syndrome Children: A Response to Gibson.

ERIC Educational Resources Information Center

Mervis, Carolyn B.; Cardoso-Martins, Claudia

1984-01-01

The study compared longitudinally performance of six Down syndrome and six nonretarded children on Object Permanence and Means-Ends Relations Scales. Results indicated that Down syndrome children progressed from Sensorimotor Stage 5 to Stage 6 at the same rate as nonretarded children, once Down's Ss slower developmental pace was considered.…

Linguistic Profiles of Children with CI as Compared with Children with Hearing or Specific Language Impairment

ERIC Educational Resources Information Center

Hoog, Brigitte E.; Langereis, Margreet C.; Weerdenburg, Marjolijn; Knoors, Harry E. T.; Verhoeven, Ludo

2016-01-01

Background: The spoken language difficulties of children with moderate or severe to profound hearing loss are mainly related to limited auditory speech perception. However, degraded or filtered auditory input as evidenced in children with cochlear implants (CIs) may result in less efficient or slower language processing as well. To provide insight…

Flight Versus Ground Out-of-hospital Rapid Sequence Intubation Success: a Systematic Review and Meta-analysis.

PubMed

Fouche, Pieter F; Stein, Christopher; Simpson, Paul; Carlson, Jestin N; Zverinova, Kristina M; Doi, Suhail A

2018-01-29

Endotracheal intubation (ETI) is a critical procedure performed by both air medical and ground based emergency medical services (EMS). Previous work has suggested that ETI success rates are greater for air medical providers. However, air medical providers may have greater airway experience, enhanced airway education, and access to alternative ETI options such as rapid sequence intubation (RSI). We sought to analyze the impact of the type of EMS on RSI success. A systematic literature search of Medline, Embase, and the Cochrane Library was conducted and eligibility, data extraction, and assessment of risk of bias were assessed independently by two reviewers. A bias-adjusted meta-analysis using a quality-effects model was conducted for the primary outcomes of overall intubation success and first-pass intubation success. Forty-nine studies were included in the meta-analysis. There was no difference in the overall success between flight and ground based EMS; 97% (95% CI 96-98) vs. 98% (95% CI 91-100), and no difference in first-pass success for flight compared to ground based RSI; 82% (95% CI 73-89) vs. 82% (95% CI 70-93). Compared to flight non-physicians, flight physicians have higher overall success 99% (95% CI 98-100) vs. 96% (95% CI 94-97) and first-pass success 89% (95% CI 77-98) vs. 71% (95% CI 57-84). Ground-based physicians and non-physicians have a similar overall success 98% (95% CI 88-100) vs. 98% (95% CI 95-100), but no analysis for physician ground first pass was possible. Both overall and first-pass success of RSI did not differ between flight and road based EMS. Flight physicians have a higher overall and first-pass success compared to flight non-physicians and all ground based EMS, but no such differences are seen for ground EMS. Our results suggest that ground EMS can use RSI with similar outcomes compared to their flight counterparts.

Design of a Permanent-Magnet Zeeman Slower

NASA Astrophysics Data System (ADS)

Adler, Charles; Narducci, Frank; Sukenik, Charles; Mulholland, Jonathan; Goodale, Sarah

2006-05-01

During the past decade, low cost, flexible, and highly-polarized magnetic field sheet material has become available with field strengths useful for applications in modern atomic physics experiments. One advantage of using such material is that it can easily be cut to almost any desired shape without appreciable loss of field strength making it more versatile than ceramic magnets. We present the design of a Zeeman slower, made from such material, for cooling an atomic beam of neutral rubidium atoms and discuss results from an atomic beam trajectory simulation which indicates that the slower should perform well. We will also report on progress of a prototype permanent magnet Zeeman slower presently under construction in the laboratory.

Flapping wing aerodynamics: from insects to vertebrates.

PubMed

Chin, Diana D; Lentink, David

2016-04-01

More than a million insects and approximately 11,000 vertebrates utilize flapping wings to fly. However, flapping flight has only been studied in a few of these species, so many challenges remain in understanding this form of locomotion. Five key aerodynamic mechanisms have been identified for insect flight. Among these is the leading edge vortex, which is a convergent solution to avoid stall for insects, bats and birds. The roles of the other mechanisms - added mass, clap and fling, rotational circulation and wing-wake interactions - have not yet been thoroughly studied in the context of vertebrate flight. Further challenges to understanding bat and bird flight are posed by the complex, dynamic wing morphologies of these species and the more turbulent airflow generated by their wings compared with that observed during insect flight. Nevertheless, three dimensionless numbers that combine key flow, morphological and kinematic parameters - the Reynolds number, Rossby number and advance ratio - govern flapping wing aerodynamics for both insects and vertebrates. These numbers can thus be used to organize an integrative framework for studying and comparing animal flapping flight. Here, we provide a roadmap for developing such a framework, highlighting the aerodynamic mechanisms that remain to be quantified and compared across species. Ultimately, incorporating complex flight maneuvers, environmental effects and developmental stages into this framework will also be essential to advancing our understanding of the biomechanics, movement ecology and evolution of animal flight. © 2016. Published by The Company of Biologists Ltd.

Comparative disposition of pharmacologic markers for cytochrome P-450 mediated metabolism, glomerular filtration rate, and extracellular and total body fluid volume of Greyhound and Beagle dogs.

PubMed

KuKanich, B; Coetzee, J F; Gehring, R; Hubin, M

2007-08-01

The purpose of the study was to compare the disposition of pharmacologic markers for cytochrome P-450 (CYP) metabolism, glomerular filtration rate (GFR), and extracellular (ECFV) and total body fluid volumes (TBFV) of Greyhounds and Beagles. Six healthy Greyhound and six healthy Beagle dogs were studied. Antipyrine, a marker for CYP metabolism and TBFV, and inulin, a marker for the GFR and ECFV, were administered i.v. Samples were collected at predetermined times and plasma was analyzed by validated high-pressure liquid chromatography (HPLC) methods. There were no differences in the disposition or pharmacokinetic parameters for inulin between the dog breeds. However, the clearance of antipyrine (mean = 8.33 mL/min/kg) in Greyhounds was significantly slower than Beagles (13.42 mL/min/kg, P = 0.004). The volume of distribution of antipyrine was significantly larger in Greyhounds (0.789 L/kg) than in Beagles (0.644 L/kg, P = 0.01). The half-life of antipyrine was significantly longer in Greyhounds (1.09 h) compared with Beagles (0.55 h, P = 0.002). The in vitro plasma protein binding of antipyrine was significantly less in Greyhounds (28%) compared with Beagles (40.3%, P = 0.008). Greyhounds exhibited significantly slower CYP metabolism, higher TBFV, and lower in vitro protein binding of antipyrine compared with Beagles. No differences in GFR or ECFV were found.

Differential rate in decline in ovarian reserve markers in women with polycystic ovary syndrome compared with control subjects: results of a longitudinal study.

PubMed

Ahmad, Asima K; Kao, Chia-Ning; Quinn, Molly; Lenhart, Nikolaus; Rosen, Mitchell; Cedars, Marcelle I; Huddleston, Heather

2018-03-01

To estimate rates of ovarian aging in polycystic ovary syndrome (PCOS) subjects versus a community control population. Longitudinal. Tertiary academic center. PCOS subjects diagnosed according to the 2004 Rotterdam criteria were systematically enrolled in a PCOS cohort study. The comparison control subjects were from the Ovarian Aging study, a prospective longitudinal study of ovarian aging in healthy women with regular menstrual cycles. Clinical data collection over two study visits. Antral follicle count (AFC), ovarian volume (OV), and antimüllerian hormone level (AMH). PCOS subjects were found to have higher baseline values for all ovarian reserve markers compared with control subjects. Univariate models indicated that, compared with control subjects, PCOS patients experienced significantly faster rates of decline for both AFC and AMH. Change in OV did not differ significantly. To account for potential confounder effects, multiple analysis of covariance models were evaluated for the best fit, considering age, body mass index, and baseline ovarian reserve markers. Adjusted models demonstrated that PCOS patients do not experience a significant difference in AFC decline compared with control subjects, but they do experience a faster rate of decline in AMH (P<.01) and slower rate of decline in OV (P<.01). Ovarian aging in PCOS is characterized by a more rapid decline in AMH and a slower decline in OV compared with control subjects. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Practical Possibilities of High-Altitude Flight with Exhaust-Gas Turbines in Connection with Spark Ignition Engines Comparative Thermodynamic and Flight Mechanical Investigations

NASA Technical Reports Server (NTRS)

Weise, A.

1947-01-01

As a means of preparing for high-altitude flight with spark-ignition engines in conjunction with exhaust-gas turbosuperchargers, various methods of modifying the exhaust-gas temperatures, which are initially higher than a turbine can withstand are mathematically compared. The thermodynamic results first obtained are then examined with respect to the effect on flight speed, climbing speed, ceiling, economy, and cruising range. The results are so presented in a generalized form that they may be applied to every appropriate type of aircraft design and a comparison with the supercharged engine without exhaust-gas turbine can be made.

Flight Capacities and Diurnal Flight Patterns of the Ambrosia Beetles, Xyleborus glabratus and Monarthrum mali (Coleoptera: Curculionidae).

PubMed

Seo, Meeja; Martini, Xavier; Rivera, Monique J; Stelinski, Lukasz L

2017-06-01

We compared the flight activity of Xyleborus glabratus Eichhoff, vector and symbiont of the causal agent of laurel wilt disease (Raffaelea lauricola), with a native species Monarthrum mali (Fitch) using flight mills. Flight mills were operated either for 24 h or for three 3-h time intervals. During the 3-h interval experiment, the shortest time to flight initiation for X. glabratus occurred at 1600-1900 hours. The average flight time and total flying distance during 1600-2100 hours were also higher than those quantified during the other two recording times investigated. However, total flight duration and proportion of fliers was highest at 1000-1300 hours. We compared several flight parameters. About 64.0% of tested X. glabratus flew <20 m. During 24-h recording periods, M. mali flew longer distances than X. glabratus. Over 50.0% of M. mali flew over 100 m on the flight mill. Xyleborus glabratus flight activity was greatest between 1200 and 1800 hours, while M. mali flew most frequently between 1500 and 2100 hours. Monarthrum mali flew more than five times more frequently than X. glabratus, and their longest single flight distance (37.5 ± 12.5 m) and total flight distance (213.7 ± 85.5 m) were greater than those of X. glabratus. These data will be useful for development of species-specific control and monitoring protocols for these ambrosia beetles based on greater understanding of their flight capacities and associated invasion distance. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A comparison of the bromination dynamics of pitch-based and vapor-grown graphite fibers

NASA Technical Reports Server (NTRS)

Gaier, J. R.

1986-01-01

The electrical resistance of pitch based P-100 fibers and experimental organic vapor grown fibers was recorded in-situ during bromination and subsequent exposure to ambient laboratory air. The results indicate that the bromination and debromination reactions proceed much slower for vapor grown fibers than for pitch based. While this may be due in part to the larger diameter of the vapor grown fibers, the majority of the effect can probably be attributed to the differences in graphene plane orientation between the fiber types. Although the reactions are slower in the vapor grown than in the pitch based fibers, the extent of reaction as measured by the change in electrical resistance is essentially the same, with comparable (or larger) decreases in resistivity. The bromination reaction proceeds with one or more plateaus in the resistance versus time curves, which suggests staging and strengthens the argument that these fibers produce true intercalation compounds.

Tidal evolution of the Galilean satellites - A linearized theory

NASA Technical Reports Server (NTRS)

Greenberg, R.

1981-01-01

The Laplace resonance among the Galilean satellites Io, Europa, and Ganymede is traditionally reduced to a pendulum-like dynamical problem by neglecting short-period variations of several orbital elements. However, some of these variations that can now be neglected may once have had longer periods, comparable to the 'pendulum' period, if the system was formerly in deep resonance (pairs of periods even closer to the ratio 2:1 than they are now). In that case, the dynamical system cannot be reduced to fewer than nine dimensions. The nine-dimensional system is linearized here in order to study small variations about equilibrium. When tidal effects are included, the resulting evolution is substantially the same as was indicated by the pendulum approach, except that evolution out of deep resonance is found to be somewhat slower than suggested by extrapolation of the pendulum results. This slower rate helps support the hypothesis that the system may have evolved from deep resonance.

Shifting attention across near and far spaces: implications for the use of hands-free cell phones while driving.

PubMed

Ferlazzo, Fabio; Fagioli, Sabrina; Di Nocera, Francesco; Sdoia, Stefano

2008-11-01

In three experiments, participants performed two tasks concurrently during driving. In the peripheral detection task, they responded manually to visual stimuli delivered through a LED placed on the internal rear mirror; in the conversation task, they were engaged in a conversation with a passenger, or through earphone-operated, loudspeaker-operated, or hand-held cell phones. Results showed that drivers were slower at responding to the visual stimuli when conversing through a hand-held cell phone or an earphone-operated cell phone than when conversing through a loudspeaker-operated cell phone or with a passenger. These results suggest that due to the brain coding the space into multiple representations, devices that make phone conversations taking place in the near, personal space make drivers slower at responding to visual stimuli, compared to devices that make the conversation occurring in a far space.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongdong, E-mail: lidongchem@sina.cn; Zhu, Yuntao; Liang, Zhiqiang

Highlights: ► The synthesized mesoporous hydroxyapatite has nanostructure and bioactivity. ► The materials have high surface area and amino group. ► The materials show higher drug loading and slower release rate than pure HAP. - Abstract: Mesoporous nanosized hydroxyapatite (HAP) functionalized by alendronate (ALN) was synthesized using cationic surfactant CTAB as template. The structural, morphological and textural properties were fully characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and N{sub 2} adsorption/desorption. Then the obtained materials were performed as drug delivery carriers using ibuprofen (IBU) as a model drug to investigate their drug storage/releasemore » properties in simulated body fluid (SBF). The materials showed relatively slower release rate compared with HAP due to the ionic interaction between -NH{sub 3}{sup +} on the matrix and -COO{sup −}belongs to IBU. The system provides a new concept for improving the drug loading or slowing down the release rate.« less

Aging and the Pathogenic Response to Burn

PubMed Central

Rani, Meenakshi; Schwacha, Martin G.

2012-01-01

Aging is an important and critical factor that contributes to the clinical outcome of burn patients. The very young and the elderly are more likely to succumb after major burn as compared to their adult counterparts. With the aging population, improved understanding of the mechanisms underlying age-associated complications after burns becomes even more demanding. It is widely accepted that elderly burn patients have significantly increased morbidity and mortality. Irrespective of the type of burn injury, the aged population shows slower recoveries and suffers more complications. Age-associated immune dysfunction, immunosenescence, may predispose the elderly burn patients to more infections, slower healing and/or to other complications. Furthermore, pre-existing, age-related medical conditions such as, pulmonary/cardiovascular dysfunctions and diabetes in the elderly are other important factors that contribute to their poorer outcomes after major burn. The present review describes the impact of aging on burn patients outcomes. PMID:22724078

Age-Group Differences in Interference from Young and Older Emotional Faces.

PubMed

Ebner, Natalie C; Johnson, Marcia K

2010-11-01

Human attention is selective, focusing on some aspects of events at the expense of others. In particular, angry faces engage attention. Most studies have used pictures of young faces, even when comparing young and older age groups. Two experiments asked (1) whether task-irrelevant faces of young and older individuals with happy, angry, and neutral expressions disrupt performance on a face-unrelated task, (2) whether interference varies for faces of different ages and different facial expressions, and (3) whether young and older adults differ in this regard. Participants gave speeded responses on a number task while irrelevant faces appeared in the background. Both age groups were more distracted by own than other-age faces. In addition, young participants' responses were slower for angry than happy faces, whereas older participants' responses were slower for happy than angry faces. Factors underlying age-group differences in interference from emotional faces of different ages are discussed.

Balance training reduces falls risk in older individuals with type 2 diabetes.

PubMed

Morrison, Steven; Colberg, Sheri R; Mariano, Mira; Parson, Henri K; Vinik, Arthur I

2010-04-01

This study assessed the effects of balance/strength training on falls risk and posture in older individuals with type 2 diabetes. Sixteen individuals with type 2 diabetes and 21 age-matched control subjects (aged 50-75 years) participated. Postural stability and falls risk was assessed before and after a 6-week exercise program. Diabetic individuals had significantly higher falls risk score compared with control subjects. The diabetic group also exhibited evidence of mild-to-moderate neuropathy, slower reaction times, and increased postural sway. Following exercise, the diabetic group showed significant improvements in leg strength, faster reaction times, decreased sway, and, consequently, reduced falls risk. Older individuals with diabetes had impaired balance, slower reactions, and consequently a higher falls risk than age-matched control subjects. However, all these variables improved after resistance/balance training. Together these results demonstrate that structured exercise has wide-spread positive effects on physiological function for older individuals with type 2 diabetes.

Analyzing the anodic reactions for iron surface with a porous Al2O3 cluster with the scanning vibrating electrode

NASA Astrophysics Data System (ADS)

Eliyan, Faysal Fayez

2017-09-01

The Scanning Vibrating Electrode Technique (SVET) was used to analyze the anodic reactions inside and around a porous Al2O3 cluster embedded onto an iron foil. The tests were carried out at -0.7 V vs. Saturated Calomel Electrode, in naturally aerated solutions of 0.1, 0.2, 0.35, and 0.5 M bicarbonate concentration. During 10 h of testing, the SVET showed evidence for a formation of a passive film in and around the cluster, in the scanning area shown in the graphical abstract. In the dilute 0.1 and 0.2 M solutions, the passive films formed slower than those in 0.35 and 0.5 M solutions. In the SVET maps, the passive films showed that they could suppress dissolution to currents comparable to those of slower dissolution under the porous Al2O3 cluster.

Viscoelastic relaxations of high alcohols and alkanes: Effects of heterogeneous structure and translation-orientation coupling

NASA Astrophysics Data System (ADS)

Yamaguchi, Tsuyoshi

2017-03-01

The frequency-dependent shear viscosity of high alcohols and linear alkanes, including 1-butanol, 1-octanol, 1-dodecanol, n-hexane, n-decane, and n-tetradecane, was calculated using molecular dynamics simulation. The relaxation of all the liquids was bimodal. The correlation functions of the collective orientation were also evaluated. The analysis of these functions showed that the slower relaxation mode of alkanes is assigned to the translation-orientation coupling, while that of high alcohols is not. The X-ray structure factors of all the alcohols showed prepeaks, as have been reported in the literature, and the intermediate scattering functions were calculated at the prepeak. Comparing the intermediate scattering function with the frequency-dependent shear viscosity based on the mode-coupling theory, it was demonstrated that the slower viscoelastic relaxation of the alcohols is assigned to the relaxation of the heterogeneous structure described by the prepeak.

Advances in Magnetic Resonance Imaging Contrast Agents for Biomarker Detection

PubMed Central

Sinharay, Sanhita; Pagel, Mark D.

2016-01-01

Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized 13C to detect the agent with outstanding sensitivity. These hyperpolarized 13C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection. PMID:27049630

Sounding Rockets as a Real Flight Platform for Aerothermodynamic Cfd Validation of Hypersonic Flight Experiments

NASA Astrophysics Data System (ADS)

Stamminger, A.; Turner, J.; Hörschgen, M.; Jung, W.

2005-02-01

This paper describes the possibilities of sounding rockets to provide a platform for flight experiments in hypersonic conditions as a supplement to wind tunnel tests. Real flight data from measurement durations longer than 30 seconds can be compared with predictions from CFD calculations. This paper will regard projects flown on sounding rockets, but mainly describe the current efforts at Mobile Rocket Base, DLR on the SHarp Edge Flight EXperiment SHEFEX.

Bone histology in extant and fossil penguins (Aves: Sphenisciformes).

PubMed

Ksepka, Daniel T; Werning, Sarah; Sclafani, Michelle; Boles, Zachary M

2015-11-01

Substantial changes in bone histology accompany the secondary adaptation to life in the water. This transition is well documented in several lineages of mammals and non-avian reptiles, but has received relatively little attention in birds. This study presents new observations on the long bone microstructure of penguins, based on histological sections from two extant taxa (Spheniscus and Aptenodytes) and eight fossil specimens belonging to stem lineages (†Palaeospheniscus and several indeterminate Eocene taxa). High bone density in penguins results from compaction of the internal cortical tissues, and thus penguin bones are best considered osteosclerotic rather than pachyostotic. Although the oldest specimens sampled in this study represent stages of penguin evolution that occurred at least 25 million years after the loss of flight, major differences in humeral structure were observed between these Eocene stem taxa and extant taxa. This indicates that the modification of flipper bone microstructure continued long after the initial loss of flight in penguins. It is proposed that two key transitions occurred during the shift from the typical hollow avian humerus to the dense osteosclerotic humerus in penguins. First, a reduction of the medullary cavity occurred due to a decrease in the amount of perimedullary osteoclastic activity. Second, a more solid cortex was achieved by compaction. In extant penguins and †Palaeospheniscus, most of the inner cortex is formed by rapid osteogenesis, resulting an initial latticework of woven-fibered bone. Subsequently, open spaces are filled by slower, centripetal deposition of parallel-fibered bone. Eocene stem penguins formed the initial latticework, but the subsequent round of compaction was less complete, and thus open spaces remained in the adult bone. In contrast to the humerus, hindlimb bones from Eocene stem penguins had smaller medullary cavities and thus higher compactness values compared with extant taxa. Although cortical lines of arrested growth have been observed in extant penguins, none was observed in any of the current sampled specimens. Therefore, it is likely that even these 'giant' penguin taxa completed their growth cycle without a major pause in bone deposition, implying that they did not undergo a prolonged fasting interval before reaching adult size. © 2015 Anatomical Society.

Bone histology in extant and fossil penguins (Aves: Sphenisciformes)

PubMed Central

Ksepka, Daniel T; Werning, Sarah; Sclafani, Michelle; Boles, Zachary M

2015-01-01

Substantial changes in bone histology accompany the secondary adaptation to life in the water. This transition is well documented in several lineages of mammals and non-avian reptiles, but has received relatively little attention in birds. This study presents new observations on the long bone microstructure of penguins, based on histological sections from two extant taxa (Spheniscus and Aptenodytes) and eight fossil specimens belonging to stem lineages (†Palaeospheniscus and several indeterminate Eocene taxa). High bone density in penguins results from compaction of the internal cortical tissues, and thus penguin bones are best considered osteosclerotic rather than pachyostotic. Although the oldest specimens sampled in this study represent stages of penguin evolution that occurred at least 25 million years after the loss of flight, major differences in humeral structure were observed between these Eocene stem taxa and extant taxa. This indicates that the modification of flipper bone microstructure continued long after the initial loss of flight in penguins. It is proposed that two key transitions occurred during the shift from the typical hollow avian humerus to the dense osteosclerotic humerus in penguins. First, a reduction of the medullary cavity occurred due to a decrease in the amount of perimedullary osteoclastic activity. Second, a more solid cortex was achieved by compaction. In extant penguins and †Palaeospheniscus, most of the inner cortex is formed by rapid osteogenesis, resulting an initial latticework of woven-fibered bone. Subsequently, open spaces are filled by slower, centripetal deposition of parallel-fibered bone. Eocene stem penguins formed the initial latticework, but the subsequent round of compaction was less complete, and thus open spaces remained in the adult bone. In contrast to the humerus, hindlimb bones from Eocene stem penguins had smaller medullary cavities and thus higher compactness values compared with extant taxa. Although cortical lines of arrested growth have been observed in extant penguins, none was observed in any of the current sampled specimens. Therefore, it is likely that even these ‘giant’ penguin taxa completed their growth cycle without a major pause in bone deposition, implying that they did not undergo a prolonged fasting interval before reaching adult size. PMID:26360700

Wintertime Emission Ratios of CO2 and NOy from Washington, D.C.-Baltimore

NASA Astrophysics Data System (ADS)

Salmon, O. E.; Shepson, P. B.; Ren, X.; Stirm, B. H.; Brown, S. S.; Fibiger, D. L.; Thornton, J. A.; Dickerson, R. R.; McDuffie, E. E.; Gurney, K. R.

2016-12-01

Cities are known to be key emitters of the combustion products carbon dioxide (CO2) and nitrogen oxides (NOx=NO+NO2), as a result of spatially concentrated combustion sources from the transportation sector and electric energy generating stations. Wintertime in mid-latitude cities provides a unique environment for these species to accumulate and react. Fewer daylight hours of relatively weak radiation, along with lower temperatures, can lead to slower oxidation of NOx, which influences the partitioning of total reactive nitrogen (NOy; the sum of NOx, NO3, N2O5, ClNO2, HNO3, acyl peroxy nitrates, and alkyl nitrates). The altered photochemical lifetimes of these reactive nitrogen species can result in unique chemistry and transport, altering the oxidizing capacity of the atmosphere within the city, and downwind of it as well. A collaborative study, employing three airborne platforms, named the Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER) was conducted in the northeastern United States in 2015 to investigate these cold season trends. Recent studies have suggested national inventories overestimate NOx emissions. We estimate city-wide emission rates of NOy from the Washington, D.C.-Baltimore area, and report their magnitude as emission factors relative to CO2. The University of Maryland's (UMD) 402B research Cessna and Purdue University's Airborne Laboratory for Atmospheric Research were instrumented to measure CO2, NO2, and other gaseous species. Measurements of NOy, and partitioning of its constituent species, were conducted from the NCAR C-130. NOy mixing ratios were estimated from the UMD and Purdue NO2 measurements using the C-130 measurements of NO2:NOy, a ratio whose magnitude is a function of time since emission from the cities. The Purdue and UMD mass balance flights around Washington, D.C.-Baltimore allow for the determination of the urban area's downwind enhancement in CO2 and estimated NOy. The urban enhancements in these gases are multiplied by the perpendicular wind speed to give the total emission rate. Here we compare our absolute NOy emission rates and the relative NOy:CO2 emission ratios from the UMD and Purdue flights to inventory estimates.

Flight simulator evaluation of a novel flight instrument display to minimize the risks of spatial disorientation.

PubMed

Braithwaite, M G; Durnford, S J; Groh, S L; Jones, H D; Higdon, A A; Estrada, A; Alvarez, E A

1998-08-01

Spatial disorientation (SD) in flight remains a major source of attrition. Many SD accidents would occur regardless of the instrument display in use, since the aircrew are simply not looking at the instruments. However, there are a number of accidents which might be amenable to improved instrument displays. In an attempt to improve maintenance and reattainment of correct orientation with a reduced cognitive workload, a novel instrument display has been developed. This paper describes an assessment of the display in a UH-60 helicopter flight simulator. This study tested the hypothesis that during instrument flight and recovery from unusual attitudes, the novel display permits a more accurate maintenance and reestablishment of flight parameters than the standard flight instruments. There were 16 male aviators who flew a simulated instrument flight profile and recovery from unusual attitudes using both the standard flight instruments and the novel display. The two display formats were tested both with and without a secondary task. When compared with the standard instruments, both control of flight parameters and recovery from unusual attitudes were significantly improved when using the novel display. Analysis of the secondary task scores showed that cognitive workload was reduced when using the novel display compared with the standard instruments. Results from all aspects of the assessment indicated benefits of the new display. Future testing should be carried out during real flight, and the display should be further developed to be used in a head-up or helmet-mounted device.

Study of the flying ability of Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) adults using a computer-monitored flight mill.

PubMed

Ávalos, J A; Martí-Campoy, A; Soto, A

2014-08-01

The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae), native to tropical Asian regions, has become a serious threat to palm trees all over the world. Knowledge of its flight potential is vital to improving the preventive and curative measures currently used to manage this pest. As R. ferrugineus is a quarantine pest, it is difficult to study its flight potential in the field. A computer-monitored flight mill was adapted to analyse the flying ability of R. ferrugineus through the study of different flight parameters (number of flights, total distance flown, longest single flight, flight duration, and average and maximum speed) and the influence of the weevil's sex, age, and body size on these flight parameters. Despite significant differences in the adult body size (body weight and length) of males and females, the sex of R. ferrugineus adults did not have an influence on their flight potential. Neither adult body size nor age was found to affect the weevil's flying abilities, although there was a significantly higher percentage of individuals flying that were 8-23 days old than 1-7 days old. Compared to the longest single flight, 54% of the insects were classified as short-distance flyers (covering <100 m) and 36 and 10% were classified as medium- (100-5000 m) and long-distance (>5000 m), respectively. The results are compared with similar studies on different insect species under laboratory and field conditions.

Cosmic Radiation Exposure of Future Hypersonic Flight Missions.

PubMed

Koops, L

2017-06-15

Cosmic radiation exposure in air traffic grows with flight altitude, geographical latitude and flight time. For future high-speed intercontinental point-to-point travel, the trade-off between reduced flight time and enhanced dose rate at higher flight altitudes is investigated. Various representative (partly) hypersonic cruise missions are considered and in dependence on solar activity the integral route dose is calculated for envisaged flight profiles and trajectories. Our results are compared to those for corresponding air connections served by present day subsonic airliners. During solar maximum, we find a significant reduction in route dose for all considered high-speed missions compared to the subsonic reference. However, during solar minimum, comparable or somewhat larger doses result on transpolar trajectories with (partly) hypersonic cruise at Mach 5. Both solar activity and routing are hence found to determine, whether passengers can profit from shorter flight times in terms of radiation exposure, despite of altitude-induced higher dose rates. Yet, aircrews with fixed number of block hours are always subject to larger annual doses, which in the considered cases take values up to five times the reference. We comment on the implications of our results for route planning and aviation decision-making in the absence of radiation shielding solutions. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

IRVE-II Post-Flight Trajectory Reconstruction

NASA Technical Reports Server (NTRS)

O'Keefe, Stephen A.; Bose, David M.

2010-01-01

NASA s Inflatable Re-entry Vehicle Experiment (IRVE) II successfully demonstrated an inflatable aerodynamic decelerator after being launched aboard a sounding rocket from Wallops Flight Facility (WFF). Preliminary day of flight data compared well with pre-flight Monte Carlo analysis, and a more complete trajectory reconstruction performed with an Extended Kalman Filter (EKF) approach followed. The reconstructed trajectory and comparisons to an attitude solution provided by NASA Sounding Rocket Operations Contract (NSROC) personnel at WFF are presented. Additional comparisons are made between the reconstructed trajectory and pre and post-flight Monte Carlo trajectory predictions. Alternative observations of the trajectory are summarized which leverage flight accelerometer measurements, the pre-flight aerodynamic database, and on-board flight video. Finally, analysis of the payload separation and aeroshell deployment events are presented. The flight trajectory is reconstructed to fidelity sufficient to assess overall project objectives related to flight dynamics and overall, IRVE-II flight dynamics are in line with expectations

Population Dynamics and Flight Phenology Model of Codling Moth Differ between Commercial and Abandoned Apple Orchard Ecosystems.

PubMed

Joshi, Neelendra K; Rajotte, Edwin G; Naithani, Kusum J; Krawczyk, Greg; Hull, Larry A

2016-01-01

Apple orchard management practices may affect development and phenology of arthropod pests, such as the codling moth (CM), Cydia pomonella (L.) (Lepidoptera: Tortricidae), which is a serious internal fruit-feeding pest of apples worldwide. Estimating population dynamics and accurately predicting the timing of CM development and phenology events (for instance, adult flight, and egg-hatch) allows growers to understand and control local populations of CM. Studies were conducted to compare the CM flight phenology in commercial and abandoned apple orchard ecosystems using a logistic function model based on degree-days accumulation. The flight models for these orchards were derived from the cumulative percent moth capture using two types of commercially available CM lure baited traps. Models from both types of orchards were also compared to another model known as PETE (prediction extension timing estimator) that was developed in 1970s to predict life cycle events for many fruit pests including CM across different fruit growing regions of the United States. We found that the flight phenology of CM was significantly different in commercial and abandoned orchards. CM male flight patterns for first and second generations as predicted by the constrained and unconstrained PCM (Pennsylvania Codling Moth) models in commercial and abandoned orchards were different than the flight patterns predicted by the currently used CM model (i.e., PETE model). In commercial orchards, during the first and second generations, the PCM unconstrained model predicted delays in moth emergence compared to current model. In addition, the flight patterns of females were different between commercial and abandoned orchards. Such differences in CM flight phenology between commercial and abandoned orchard ecosystems suggest potential impact of orchard environment and crop management practices on CM biology.

Population Dynamics and Flight Phenology Model of Codling Moth Differ between Commercial and Abandoned Apple Orchard Ecosystems

PubMed Central

Joshi, Neelendra K.; Rajotte, Edwin G.; Naithani, Kusum J.; Krawczyk, Greg; Hull, Larry A.

2016-01-01

Apple orchard management practices may affect development and phenology of arthropod pests, such as the codling moth (CM), Cydia pomonella (L.) (Lepidoptera: Tortricidae), which is a serious internal fruit-feeding pest of apples worldwide. Estimating population dynamics and accurately predicting the timing of CM development and phenology events (for instance, adult flight, and egg-hatch) allows growers to understand and control local populations of CM. Studies were conducted to compare the CM flight phenology in commercial and abandoned apple orchard ecosystems using a logistic function model based on degree-days accumulation. The flight models for these orchards were derived from the cumulative percent moth capture using two types of commercially available CM lure baited traps. Models from both types of orchards were also compared to another model known as PETE (prediction extension timing estimator) that was developed in 1970s to predict life cycle events for many fruit pests including CM across different fruit growing regions of the United States. We found that the flight phenology of CM was significantly different in commercial and abandoned orchards. CM male flight patterns for first and second generations as predicted by the constrained and unconstrained PCM (Pennsylvania Codling Moth) models in commercial and abandoned orchards were different than the flight patterns predicted by the currently used CM model (i.e., PETE model). In commercial orchards, during the first and second generations, the PCM unconstrained model predicted delays in moth emergence compared to current model. In addition, the flight patterns of females were different between commercial and abandoned orchards. Such differences in CM flight phenology between commercial and abandoned orchard ecosystems suggest potential impact of orchard environment and crop management practices on CM biology. PMID:27713702

Midodrine as a Countermeasure to Orthostatic Hypotension Immediately After Space Shuttle Landing

NASA Technical Reports Server (NTRS)

Platts, Steven H.; Stenger, Michael B.; Ribeiro, L. Christine; Lee, Stuart M. C.

2010-01-01

Midodrine prevents post-space flight orthostatic intolerance when testing is conducted in a controlled laboratory setting within 2-4 hours after Space Shuttle landing. It is unknown if midodrine is as effective during re-entry and immediately following landing. METHODS: Cardiovascular responses to 10 minutes of 80 head-up tilt in five male astronauts were compared before and immediately after Space Shuttle missions. Preflight tests were conducted in the Johnson Space Center Cardiovascular Laboratory without midodrine. Post-flight testing was performed in the Crew Transport Vehicle on the Space Shuttle runway within 60 minutes of landing; midodrine was self-administered before re-entry. Survival analysis was performed (Gehan-Breslow test) to compare presyncope rates pre- to post-flight. Cardiovascular responses (last minute standing minus supine) to tilt before and after space flight were compared using paired t-tests. RESULTS: Midodrine did not prevent post-flight orthostatic hypotension in two of the five astronauts, but the rate of presyncope across the group did not increase (p=0.17) from pre- to post-flight. Also, although the change in heart rate from supine to the last minute of standing was not affected by space flight, systolic blood pressure decreased more (p=0.05) and diastolic blood pressure tended to decrease (p=0.08) after space flight. CONCLUSIONS: Accurate interpretation of the current results requires that similar data be collected in control subjects (without midodrine) on the CTV. However, drug interaction concerns with commonly used anti-emetics and potentiation of prolonged QTc intervals observed in long duration astronauts make the routine use of midodrine for immediate post-flight orthostatic hypotension unlikely. 2

Risk Factors for Injury and Cigarette Smoking and Temporal Trends in Demographic and Lifestyle Characteristics Among U.S. Army Ordinance School Students

DTIC Science & Technology

2008-07-01

took 166 ± 92 days or had a 24% slower healing time to clinical union , compared with nonsmokers at 134 ± 71 days. Possible attributes of the delayed ...1993). Are smokers a risk group for delayed healing of tibial shaft fractures . Annales Chirurgiae et Gynaeacologiae, 82:254-262. 47. Mazess R...experience stress fractures , compared with Caucasians(29), possibly because Blacks having a higher bone density(30,31).Other studies performed

A comparison of Wortmann airfoil computer-generated lift and drag polars with flight and wind tunnel results

NASA Technical Reports Server (NTRS)

Bowers, A. H.; Sim, A. G.

1984-01-01

Computations of drag polars for a low-speed Wortmann sailplane airfoil are compared with both wind tunnel and flight test results. Excellent correlation was shown to exist between computations and flight results except when separated flow regimes were encountered. Smoothness of the input coordinates to the PROFILE computer program was found to be essential to obtain accurate comparisons of drag polars or transition location to either the flight or wind tunnel flight results.

Rise in prostate-specific antigen in men with untreated low-grade prostate cancer is slower during spring-summer.

PubMed

Vieth, R; Choo, R; Deboer, L; Danjoux, C; Morton, G C; Klotz, L

2006-01-01

To test the hypothesis that the rate of rise in prostate-specific antigen (PSA) is slower during the spring-summer than during the rest of the year, we used PSA data from a prospective single-arm cohort study of men who had been followed to characterize a watchful observation protocol with selective delayed intervention for clinically localized, low-to-intermediate grade prostate adenocarcinoma. The rate of PSA increase was calculated as the visit-to-visit slope of log (PSA) against time, from 1 calendar-quarter visit to the next. The nonparametric Friedman test confirmed differences in rate of PSA rise among the calendar quarters (P = 0.041). Post hoc analysis showed the rate of PSA increase during Q2 was significantly slower than in each one of the other calendar quarters (Q1 versus Q2, P = 0.025; Q3 versus Q2, P = 0.002; Q4 versus Q2, P = 0.013), with no differences among quarters Q1, Q3, and Q4. These results are consistent with the vitamin D hypothesis that the higher 25-hydroxyvitamin D levels associated with spring and summer have a desirable effect on prostate biology. The therapeutic implication is that vitamin D supplementation in the range of 2000 IU/d, a dose comparable to the effect of summer, can benefit men monitored for rising PSA.

Evaluating the Recovery Curve for Clinically Assessed Reaction Time After Concussion.

PubMed

Del Rossi, Gianluca

2017-08-01

  A change in reaction time is one of various clinical measures of neurocognitive function that can be monitored after concussion and has been reported to be among the most sensitive indicators of cognitive impairment.   To determine the timeline for clinically assessed simple reaction time to return to baseline after a concussion in high school athletes.   Observational study.   Athletic training room.   Twenty-one high school-aged volunteers.   Participants completed 8 trials of the ruler-drop test during each session. Along with baseline measures, a total of 6 additional test sessions were completed over the course of 4 weeks after a concussion (days 3, 7, 10, 14, 21, and 28).   The mean reaction times calculated for all participants from each of the 7 test sessions were analyzed to assess the change in reaction time over the 7 time intervals.   After a concussion and compared with baseline, simple reaction time was, on average, 26 milliseconds slower at 48 to 72 hours postinjury (P < .001), almost 18 milliseconds slower on day 7 (P < .001), and about 9 milliseconds slower on day 10 (P < .001). Simple reaction time did not return to baseline levels until day 14 postinjury.   Clinically assessed simple reaction time appeared to return to baseline levels within a timeframe that mirrors other measures of cognitive performance (approximately 14 days).

Functioning of the Ocean Biological Pump in the Oxygen Minimum Zones

NASA Astrophysics Data System (ADS)

Moore, J. K.

2015-12-01

Oxygen minimum zones occur at mid-depths in the water column in regions with weak ventilation and relatively high export of organic matter from surface waters. They are important ocean for ocean biogeochemistry, and potentially for climate, as sites of water column denitrification and nitrous oxide production. Denitrification is the dominant loss process for fixed nitrogen in the oceans, and can thus affect the ocean inventory of this key nutrient. Denitrification is less energetically efficient than oxic remineralization. Larger zooplankton, which feed on sinking particles, are not present in the lowest oxygen waters. Both of these factors suggest that the remineralization of sinking particles may be slower within the OMZs than in more oxygenated waters. There is limited field evidence and from some modeling studies that remineralization is slower (remineralization length scales are longer) within OMZ waters. In this talk, I will present results from the Community Earth System Model (CESM) ocean component attempting to test this hypothesis. Comparing model results with observed ocean biogeochemical tracer distributions (i.e., phosphate, oxygen), I will examine whether slower remineralization within low oxygen waters provides a better match between simulated and observed tracer distributions. Longer remineralization length scales under low oxygen conditions would provide a negative feedback under global warming scenarios. The biological pump would transfer organic materials to depth more efficiently as ocean oxygen concentrations decline and the OMZs expand.

Incomplete proteasomal degradation of green fluorescent proteins in the context of tandem fluorescent protein timers

PubMed Central

Khmelinskii, Anton; Meurer, Matthias; Ho, Chi-Ting; Besenbeck, Birgit; Füller, Julia; Lemberg, Marius K.; Bukau, Bernd; Mogk, Axel; Knop, Michael

2016-01-01

Tandem fluorescent protein timers (tFTs) report on protein age through time-dependent change in color, which can be exploited to study protein turnover and trafficking. Each tFT, composed of two fluorescent proteins (FPs) that differ in maturation kinetics, is suited to follow protein dynamics within a specific time range determined by the maturation rates of both FPs. So far, tFTs have been constructed by combining slower-maturing red fluorescent proteins (redFPs) with the faster-maturing superfolder green fluorescent protein (sfGFP). Toward a comprehensive characterization of tFTs, we compare here tFTs composed of different faster-maturing green fluorescent proteins (greenFPs) while keeping the slower-maturing redFP constant (mCherry). Our results indicate that the greenFP maturation kinetics influences the time range of a tFT. Moreover, we observe that commonly used greenFPs can partially withstand proteasomal degradation due to the stability of the FP fold, which results in accumulation of tFT fragments in the cell. Depending on the order of FPs in the timer, incomplete proteasomal degradation either shifts the time range of the tFT toward slower time scales or precludes its use for measurements of protein turnover. We identify greenFPs that are efficiently degraded by the proteasome and provide simple guidelines for the design of new tFTs. PMID:26609072

Delayed expression of SAGs correlates with longevity in CMS wheat plants compared to its fertile plants.

PubMed

Semwal, Vimal Kumar; Singh, Bhupinder; Khanna-Chopra, Renu

2014-04-01

Reproductive sinks regulate monocarpic senescence in crop plants. Monocarpic senescence was studied in wheat fertile (cv. HW 2041) and its isonuclear cytoplasmic male sterile (CMS) line. CMS plants exhibited slower rate of senescence accompanied by longer green leaf area duration and slower deceleration in chlorophyll, protein content, PN and rubisco content coupled with lower protease activities than fertile (F) plants. CMS plants also exhibited lower ROS levels and less membrane damage than F plants. CMS plants maintained better antioxidant defense, less oxidative damage in chloroplast and higher transcript levels of both rbcL and rbcS genes during senescence than F plants. F plants exhibited early induction and higher expression of SAGs like serine and cysteine proteases, glutamine synthetases GS1 and GS2, WRKY53 transcription factor and decline in transcript levels of CAT1 and CAT2 genes than CMS plants. Hence, using genetically fertile and its CMS line of wheat it is confirmed that delayed senescence in the absence of reproductive sinks is linked with slower protein oxidation, rubisco degradation and delayed activation of SAGs. Better antioxidant defense in chloroplasts at later stages of senescence was able to mitigate the deleterious effects of ROS in CMS plants. We propose that delayed increase in ROS in cytoplasmic male sterile wheat plants resulted in delayed activation of WRKY53, SAGs and the associated biochemical changes than fertile plants.

Homologization of the flight musculature of zygoptera (insecta: odonata) and neoptera (insecta).

PubMed

Büsse, Sebastian; Genet, Cécile; Hörnschemeyer, Thomas

2013-01-01

Among the winged insects (Pterygota) the Dragonflies and Damselflies (Odonata) are unique for several reasons. Behaviourally they are aerial predators that hunt and catch their prey in flight, only. Morphologically the flight apparatus of Odonata is significantly different from what is found in the remaining Pterygota. However, to understand the phylogenetic relationships of winged insects and the origin and evolution of insect flight in general, it is essential to know how the elements of the odonatan flight apparatus relate to those of the other Pterygota. Here we present a comprehensive, comparative morphological investigation of the thoracic flight musculature of damselflies (Zygoptera). Based on our new data we propose a homologization scheme for the thoracic musculature throughout Pterygota. The new homology hypotheses will allow for future comparative work and especially for phylogenetic analyses using characters of the thoracic musculature throughout all winged insects. This will contribute to understand the early evolution of pterygote insects and their basal phylogenetic relationship.

Homologization of the Flight Musculature of Zygoptera (Insecta: Odonata) and Neoptera (Insecta)

PubMed Central

Büsse, Sebastian; Genet, Cécile; Hörnschemeyer, Thomas

2013-01-01

Among the winged insects (Pterygota) the Dragonflies and Damselflies (Odonata) are unique for several reasons. Behaviourally they are aerial predators that hunt and catch their prey in flight, only. Morphologically the flight apparatus of Odonata is significantly different from what is found in the remaining Pterygota. However, to understand the phylogenetic relationships of winged insects and the origin and evolution of insect flight in general, it is essential to know how the elements of the odonatan flight apparatus relate to those of the other Pterygota. Here we present a comprehensive, comparative morphological investigation of the thoracic flight musculature of damselflies (Zygoptera). Based on our new data we propose a homologization scheme for the thoracic musculature throughout Pterygota. The new homology hypotheses will allow for future comparative work and especially for phylogenetic analyses using characters of the thoracic musculature throughout all winged insects. This will contribute to understand the early evolution of pterygote insects and their basal phylogenetic relationship. PMID:23457479

Evaluation of the in vivo disintegration of solid dosage forms of a bile acid sequestrant in dogs using gamma-scintigraphy and correlation to in vitro disintegration.

PubMed

Hussain, Munir A; Chang, Rong-Kun; Sandefer, Erik; Page, Richard C; Digenis, George A

2003-03-01

[corrected] To evaluate the in vivo disintegration behavior of tablets and capsules of a bile acid sequestrant, DMP 504, in beagle dogs and to assess the significance of the in vitro disintegration of the dosage forms on subsequent in vivo behavior in order to draw possible in vitro-in vivo correlations. Tablet and capsule formulations of a bile acid sequestrant, DMP 504, were formulated with samarium oxide and neutron activated to produce radioactive 53Sm to noninvasively evaluate their in vivo behavior in beagle dogs by gamma-scintigraphy. A four-way crossover design was completed (n = 4) in which (a) tablets from two different batches were administered under the fasted condition and manufactured using different lots of drug substance where one batch exhibited relatively faster in vitro disintegration time (30 min) than the other tablet batch, which resulted in slower disintegration (45 min), (b) a capsule formulation was administered to fasted beagles, and (c) the tablet having slower in vitro disintegration was also administered in the fed state, and its in vivo disintegration was compared to that observed in the fasted state. Tablets manufactured using a lot of DMP 504 having relatively fast in vitro disintegration (approximately 30 min) resulted in relatively rapid in vivo disintegration time (15 min) in the fasted condition. This in vivo disintegration time was comparable to the in vivo disintegration of the capsules (17 min) even though the in vitro capsule disintegration time was considerably faster (2 min). Tablets prepared using a drug substance that provided a longer in vitro disintegration time (approximately 45 min) resulted in a slower in vivo disintegration (63 min). There was no difference observed in the in vivo disintegration behavior in fasted and fed dogs for the tablets that provided slower in vitro disintegration. In vivo disintegration of tablets of the bile acid sequestrant DMP 504 correlated with in vitro disintegration times. Gamma-Scintigraphy continues to be a good tool to use during early stages of product development to investigate in vivo performance of dosage forms. The results of this study provided evidence that the physical chemical specifications of the drug substance may not always be indicative of in vitro or in vivo performance of tablet dosage form, even when formulation and process are not changed.

Challenges in Rotorcraft Acoustic Flight Prediction and Validation

NASA Technical Reports Server (NTRS)

Boyd, D. Douglas, Jr.

2003-01-01

Challenges associated with rotorcraft acoustic flight prediction and validation are examined. First, an outline of a state-of-the-art rotorcraft aeroacoustic prediction methodology is presented. Components including rotorcraft aeromechanics, high resolution reconstruction, and rotorcraft acoustic prediction arc discussed. Next, to illustrate challenges and issues involved, a case study is presented in which an analysis of flight data from a specific XV-15 tiltrotor acoustic flight test is discussed in detail. Issues related to validation of methodologies using flight test data are discussed. Primary flight parameters such as velocity, altitude, and attitude are discussed and compared for repeated flight conditions. Other measured steady state flight conditions are examined for consistency and steadiness. A representative example prediction is presented and suggestions are made for future research.

Flight testing of airbreathing hypersonic vehicles

NASA Technical Reports Server (NTRS)

Hicks, John W.

1993-01-01

Using the scramjet engine as the prime example of a hypersonic airbreathing concept, this paper reviews the history of and addresses the need for hypersonic flight tests. It also describes how such tests can contribute to the development of airbreathing technology. Aspects of captive-carry and free-flight concepts are compared. An incremental flight envelope expansion technique for manned flight vehicles is also described. Such critical issues as required instrumentation technology and proper scaling of experimental devices are addressed. Lastly, examples of international flight test approaches, existing programs, or concepts currently under study, development, or both, are given.

Bird flight and airplane flight. [instruments to measure air currents and flight characteristics

NASA Technical Reports Server (NTRS)

Magnan, A.

1980-01-01

Research was based on a series of mechanical, electrical, and cinematographic instruments developed to measure various features of air current behavior as well as bird and airplane flight. Investigation of rising obstruction and thermal currents led to a theory of bird flight, especially of the gliding and soaring types. It was shown how a knowledge of bird flight can be applied to glider and ultimately motorized aircraft construction. The instruments and methods used in studying stress in airplanes and in comparing the lift to drag ratios of airplanes and birds are described.

Flight determined lift and drag characteristics of an F-8 airplane modified with a supercritical wing with comparison to wind-tunnel results

NASA Technical Reports Server (NTRS)

Pyle, J. S.; Steers, L. L.

1975-01-01

Flight measurements obtained with a TF-8A airplane modified with a supercritical wing are presented for altitudes from 7.6 kilometers (25,000 feet) to 13.7 kilometers (45,000 feet), Mach numbers from 0.6 to 1.2, and Reynolds numbers from 0.8 x 10 to the 7th power to 2.3 x 10 to the 7th power. Flight results for the airplane with and without area-rule fuselage fairings are compared. The techniques used to determine the lift and drag characteristics of the airplane are discussed. Flight data are compared with wind-tunnel model results, where applicable.

Aerobic power and flight capacity in birds: a phylogenetic test of the heart-size hypothesis.

PubMed

Nespolo, Roberto F; González-Lagos, César; Solano-Iguaran, Jaiber J; Elfwing, Magnus; Garitano-Zavala, Alvaro; Mañosa, Santiago; Alonso, Juan Carlos; Altimiras, Jordi

2018-01-09

Flight capacity is one of the most important innovations in animal evolution; it only evolved in insects, birds, mammals and the extinct pterodactyls. Given that powered flight represents a demanding aerobic activity, an efficient cardiovascular system is essential for the continuous delivery of oxygen to the pectoral muscles during flight. It is well known that the limiting step in the circulation is stroke volume (the volume of blood pumped from the ventricle to the body during each beat), which is determined by the size of the ventricle. Thus, the fresh mass of the heart represents a simple and repeatable anatomical measure of the aerobic power of an animal. Although several authors have compared heart masses across bird species, a phylogenetic comparative analysis is still lacking. By compiling heart sizes for 915 species and applying several statistical procedures controlling for body size and/or testing for adaptive trends in the dataset (e.g. model selection approaches, phylogenetic generalized linear models), we found that (residuals of) heart size is consistently associated with four categories of flight capacity. In general, our results indicate that species exhibiting continuous hovering flight (i.e. hummingbirds) have substantially larger hearts than other groups, species that use flapping flight and gliding show intermediate values, and that species categorized as poor flyers show the smallest values. Our study reveals that on a broad scale, routine flight modes seem to have shaped the energetic requirements of birds sufficiently to be anatomically detected at the comparative level. © 2018. Published by The Company of Biologists Ltd.

In-flight Assessment of Lower Body Negative Pressure as a Countermeasure for Post-flight Orthostatic Intolerance

NASA Technical Reports Server (NTRS)

Charles, J. B.; Stenger, M. B.; Phillips, T. R.; Arzeno, N. M.; Lee, S. M. C.

2009-01-01

Introduction. We investigated the efficacy of combining fluid loading with sustained lower body negative pressure (LBNP) to reverse orthostatic intolerance associated with weightlessness during and immediately after Space Shuttle missions. Methods. Shuttle astronauts (n=13) underwent 4 hours of LBNP at -30 mm(Hg) and ingested water and salt ( soak treatment) during flight in two complementary studies. In the first study (n=8), pre-flight heart rate (HR) and blood pressure (BP) responses to an LBNP ramp (5-min stages of -10 mm(Hg) steps to -50 mm(Hg) were compared to responses in-flight one and two days after LBNP soak treatment. In the second study (n=5), the soak was performed 24 hr before landing, and post-flight stand test results of soak subjects were compared with those of an untreated cohort (n=7). In both studies, the soak was scheduled late in the mission and was preceded by LBNP ramp tests at approximately 3-day intervals to document the in-flight loss of orthostatic tolerance. Results. Increased HR and decreased BP responses to LBNP were evident early in-flight. In-flight, one day after LBNP soak, HR and BP responses to LBNP were not different from pre-flight, but the effect was absent the second day after treatment. Post-flight there were no between-group differences in HR and BP responses to standing, but all 5 treatment subjects completed the 5-minute stand test whereas 2 of 7 untreated cohort subjects did not. Discussion. Exaggerated HR and BP responses to LBNP were evident within the first few days of space flight, extending results from Skylab. The combined LBNP and fluid ingestion countermeasure restored in-flight LBNP HR and BP responses to pre-flight levels and provided protection of post-landing orthostatic function. Unfortunately, any benefits of the combined countermeasure were offset by the complexity of its implementation, making it inappropriate for routine application during Shuttle flights.

On Why Wayne Dennis Found Hopi Infants Retarded in Age at Onset of Walking.

ERIC Educational Resources Information Center

Harriman, Arthur E.; Lukosius, Patricia A.

1982-01-01

In 1940 Dennis found Hopi infants slower in onset of walking, whether or not the cradleboard was used. Present differences in genetic background, health, and nutrition were compared showing that an inadequate diet may have accounted for former walking delays. The present onset of walking may reflect external food program improvements in nutrition.…

Children with Dyslexia Are Slow Writers Because They Pause More Often and Not Because They Are Slow at Handwriting Execution

ERIC Educational Resources Information Center

Sumner, Emma; Connelly, Vincent; Barnett, Anna L.

2013-01-01

It is commonly assumed that children with dyslexia are slower at handwriting than other children. However, evidence of slow handwriting in children with dyslexia is very mixed. Thirty-one children with dyslexia, aged 9 years, were compared to both age-matched children and younger spelling-ability matched children. Participants completed an…

The Locus of Naming Difficulties in Children with Dyslexia: Evidence of Inefficient Phonological Encoding

ERIC Educational Resources Information Center

Truman, Amanda; Hennessey, Neville W.

2006-01-01

Twenty-four children with dyslexia (aged 7;7 to 12;1) and twenty-four age-matched controls named pictures aloud while hearing nonsense syllables either phonologically related (i.e., part of) or unrelated to the target picture name. Compared with controls, dyslexics had slower reaction times overall and, for low frequency items, the degree of…

An on-farm trial evaluating the effect of fast and slow growing genotypes on meat quality of chickens reared on a local pasture

USDA-ARS?s Scientific Manuscript database

There has been increasing interest among the consumers for free range and organic poultry in recent years. Even though heritage breed birds grow much slower compared to commercial breeds, many free range producers believe that they are better suited for outdoor production systems. We conducted an on...

Oral Braille Reading Decoding Strategies of Middle School Students Who Are Blind or Have Low Vision

ERIC Educational Resources Information Center

Nannemann, Allison C.; Bruce, Susan M.; Hussey, Colleen; Vercollone, Becky S.; McCarthy, Mary

2017-01-01

Students who are visually impaired may face unique literacy challenges as they learn to read and write braille. One such challenge relates to slower reading speeds for students who read braille as compared to those who read print. In addition to learning letters, sounds, grammar, and spelling, braille readers must learn contractions and…

61. The World-Wide Inaccessible Web, Part 2: Internet Routes

ERIC Educational Resources Information Center

Baggaley, Jon; Batpurev, Batchuluun; Klaas, Jim

2007-01-01

In the previous report in this series, Web browser loading times were measured in 12 Asian countries, and were found to be up to four times slower than commonly prescribed as acceptable. Failure of webpages to load at all was frequent. The current follow-up study compares these loading times with the complexity of the Internet routes linking the…

Altered processing of visual emotional stimuli in posttraumatic stress disorder: an event-related potential study.

PubMed

Saar-Ashkenazy, Rotem; Shalev, Hadar; Kanthak, Magdalena K; Guez, Jonathan; Friedman, Alon; Cohen, Jonathan E

2015-08-30

Patients with posttraumatic stress disorder (PTSD) display abnormal emotional processing and bias towards emotional content. Most neurophysiological studies in PTSD found higher amplitudes of event-related potentials (ERPs) in response to trauma-related visual content. Here we aimed to characterize brain electrical activity in PTSD subjects in response to non-trauma-related emotion-laden pictures (positive, neutral and negative). A combined behavioral-ERP study was conducted in 14 severe PTSD patients and 14 controls. Response time in PTSD patients was slower compared with that in controls, irrespective to emotional valence. In both PTSD and controls, response time to negative pictures was slower compared with that to neutral or positive pictures. Upon ranking, both control and PTSD subjects similarly discriminated between pictures with different emotional valences. ERP analysis revealed three distinctive components (at ~300, ~600 and ~1000 ms post-stimulus onset) for emotional valence in control subjects. In contrast, PTSD patients displayed a similar brain response across all emotional categories, resembling the response of controls to negative stimuli. We interpret these findings as a brain-circuit response tendency towards negative overgeneralization in PTSD. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Rumen clearance rates in relation to the occurrence of alfalfa bloat in cattle. 1. Passage of water-soluble markers.

PubMed

Majak, W; Hall, J W; Rode, L M; Kalnin, C M

1986-06-01

Ruminal chlorophyll and rates of passage of two water-soluble markers were simultaneously determined in cattle with different susceptibilities to alfalfa bloat. The markers showed a slower rate of passage from the rumens of more susceptible cattle where the average half-lives for cobalt-ethylenediaminetetraacetic acid and chromium-ethylenediaminetetraacetic acid were 12 to 17 h. Average half-life of the markers was 8 h in the rumens of the less susceptible animals. In agreement, chloroplast particles in the liquid phase of rumen contents showed greater accumulation in animals susceptible to bloat, but many more observations were required to detect differences in chlorophyll among animals. This was partly due to the unhomogeneous dispersion of chloroplast fragments in the reticulorumen compared with the uniform distribution of the inert markers. Differences in rumen volumes (estimated from the quantity of marker administered and its initial concentration) were detected among animals, but these did not show a relationship to bloat susceptibility. In vitro studies indicated that alfalfa chloroplast particles were not readily degraded by rumen microorganisms. Our results support earlier conclusions on slower rates of salivation for cattle that bloat compared with those that do not.

[Comparable disorder of the body schema in patients with complex regional pain syndrome (CRPS) and phantom pain].

PubMed

Reinersmann, A; Haarmeyer, G S; Blankenburg, M; Frettlöh, J; Krumova, E K; Ocklenburg, S; Maier, C

2011-09-01

In patients with complex regional pain syndrome (CRPS) a disruption of the body schema has been shown in an altered cortical representation of the hand and in delayed reaction times (RT) in the hand laterality recognition task. However, the role of attentional processes or the effect of isolated limb laterality training has not yet been clarified. The performance of healthy subjects (n = 38), CRPS patients (n = 12) and phantom limb pain (PLP) patients (n = 12) in a test battery of attentional performance (TAP) and in a limb laterality recognition task was compared and the effect of limb laterality training in CRPS patients and healthy subjects evaluated. The RTs of both CRPS and PLP patients were significantly slower than those of healthy subjects despite normal TAP values. The CRPS and PLP patients showed bilaterally delayed RTs. Through training RTs improved significantly but the RTs of CRPS patients remained slower than those of healthy subjects. In this study an equal disruption of the body schema was found in both CRPS and PLP patients which cannot be accounted for by attentional processes. For CRPS patients this disorder cannot be fully reversed by isolated limb laterality recognition training.

Attentional bias for trauma-related words: exaggerated emotional Stroop effect in Afghanistan and Iraq war veterans with PTSD.

PubMed

Ashley, Victoria; Honzel, Nikki; Larsen, Jary; Justus, Timothy; Swick, Diane

2013-03-14

Post-traumatic stress disorder (PTSD) involves debilitating symptoms that can disrupt cognitive functioning. The emotional Stroop has been commonly used to examine the impact of PTSD on attentional control, but no published study has yet used it with Afghanistan and Iraq war veterans, and only one previous study has compared groups on habituation to trauma-related words. We administered the emotional Stroop, the Beck Depression Inventory (BDI), and the PTSD Checklist (PCL) to 30 veterans with PTSD, 30 military controls, and 30 civilian controls. Stroop word types included Combat, Matched-neutral, Neutral, Positive and Negative. Compared to controls, veterans with PTSD were disproportionately slower in responding to Combat words. They were also slower and less accurate overall, did not show interference on Negative or Positive words relative to Neutral, and showed a trend for delayed but successful habituation to Combat words. Higher PCL and BDI scores also correlated with larger interference effects. Because of its specificity in detecting attentional biases to trauma-related words, the emotional Stroop task may serve as a useful pre- and post task with intervention studies of PTSD patients.

Increased effect of target eccentricity on covert shifts of visual attention in patients with neglect.

PubMed

Hamilton, Roy H; Stark, Marianna; Coslett, H Branch

2010-01-01

Debate continues regarding the mechanisms underlying covert shifts of visual attention. We examined the relationship between target eccentricity and the speed of covert shifts of attention in normal subjects and patients with brain lesions using a cued-response task in which cues and targets were presented at 2 degrees or 8 degrees lateral to the fixation point. Normal subjects were slower on invalid trials in the 8 degrees as compared to 2 degrees condition. Patients with right-hemisphere stroke with neglect were slower in their responses to left-sided invalid targets compared to valid targets, and demonstrated a significant increase in the effect of target validity as a function of target eccentricity. Additional data from one neglect patient (JM) demonstrated an exaggerated validity x eccentricity x side interaction for contralesional targets on a cued reaction time task with a central (arrow) cue. We frame these results in the context of a continuous 'moving spotlight' model of attention, and also consider the potential role of spatial saliency maps. By either account, we argue that neglect is characterized by an eccentricity-dependent deficit in the allocation of attention.

An investigation of spatial representation of pitch in individuals with congenital amusia.

PubMed

Lu, Xuejing; Sun, Yanan; Thompson, William Forde

2017-09-01

Spatial representation of pitch plays a central role in auditory processing. However, it is unknown whether impaired auditory processing is associated with impaired pitch-space mapping. Experiment 1 examined spatial representation of pitch in individuals with congenital amusia using a stimulus-response compatibility (SRC) task. For amusic and non-amusic participants, pitch classification was faster and more accurate when correct responses involved a physical action that was spatially congruent with the pitch height of the stimulus than when it was incongruent. However, this spatial representation of pitch was not as stable in amusic individuals, revealed by slower response times when compared with control individuals. One explanation is that the SRC effect in amusics reflects a linguistic association, requiring additional time to link pitch height and spatial location. To test this possibility, Experiment 2 employed a colour-classification task. Participants judged colour while ignoring a concurrent pitch by pressing one of two response keys positioned vertically to be congruent or incongruent with the pitch. The association between pitch and space was found in both groups, with comparable response times in the two groups, suggesting that amusic individuals are only slower to respond to tasks involving explicit judgments of pitch.

Reduced intrinsic heart rate is associated with reduced arrhythmic susceptibility in guinea-pig heart.

PubMed

Osadchii, Oleg E

2014-12-01

In the clinical setting, patients with slower resting heart rate are less prone to cardiovascular death compared with those with elevated heart rate. However, electrophysiological adaptations associated with reduced cardiac rhythm have not been thoroughly explored. In this study, relationships between intrinsic heart rate and arrhythmic susceptibility were examined by assessments of action potential duration (APD) rate adaptation and inducibility of repolarization alternans in sinoatrial node (SAN)-driven and atrioventricular (AV)-blocked guinea-pig hearts perfused with Langendorff apparatus. Electrocardiograms, epicardial monophasic action potentials, and effective refractory periods (ERP) were assessed in normokalemic and hypokalemic conditions. Slower basal heart rate in AV-blocked hearts was associated with prolonged ventricular repolarization during spontaneous beating, and with attenuated APD shortening at increased cardiac activation rates during dynamic pacing, when compared with SAN-driven hearts. During hypokalemic perfusion, the inducibility of repolarization alternans and tachyarrhythmia by rapid pacing was found to be lower in AV-blocked hearts. This difference was ascribed to prolonged ERP in the setting of reduced basal heart rate, which prevented ventricular capture at critically short pacing intervals required to induce arrhythmia. Reduced basal heart rate is associated with electrophysiological changes that prevent electrical instability upon an abrupt cardiac acceleration.

Attentional bias for trauma-related words: exaggerated emotional Stroop effect in Afghanistan and Iraq war veterans with PTSD

PubMed Central

2013-01-01

Background Post-traumatic stress disorder (PTSD) involves debilitating symptoms that can disrupt cognitive functioning. The emotional Stroop has been commonly used to examine the impact of PTSD on attentional control, but no published study has yet used it with Afghanistan and Iraq war veterans, and only one previous study has compared groups on habituation to trauma-related words. Methods We administered the emotional Stroop, the Beck Depression Inventory (BDI), and the PTSD Checklist (PCL) to 30 veterans with PTSD, 30 military controls, and 30 civilian controls. Stroop word types included Combat, Matched-neutral, Neutral, Positive and Negative. Results Compared to controls, veterans with PTSD were disproportionately slower in responding to Combat words. They were also slower and less accurate overall, did not show interference on Negative or Positive words relative to Neutral, and showed a trend for delayed but successful habituation to Combat words. Higher PCL and BDI scores also correlated with larger interference effects. Conclusions Because of its specificity in detecting attentional biases to trauma-related words, the emotional Stroop task may serve as a useful pre- and post task with intervention studies of PTSD patients. PMID:23496805

The role of semantically related distractors during encoding and retrieval of words in long-term memory.

PubMed

Meade, Melissa E; Fernandes, Myra A

2016-07-01

We examined the influence of divided attention (DA) on recognition of words when the concurrent task was semantically related or unrelated to the to-be-recognised target words. Participants were asked to either study or retrieve a target list of semantically related words while simultaneously making semantic decisions (i.e., size judgements) to another set of related or unrelated words heard concurrently. We manipulated semantic relatedness of distractor to target words, and whether DA occurred during the encoding or retrieval phase of memory. Recognition accuracy was significantly diminished relative to full attention, following DA conditions at encoding, regardless of relatedness of distractors to study words. However, response times (RTs) were slower with related compared to unrelated distractors. Similarly, under DA at retrieval, recognition RTs were slower when distractors were semantically related than unrelated to target words. Unlike the effect from DA at encoding, recognition accuracy was worse under DA at retrieval when the distractors were related compared to unrelated to the target words. Results suggest that availability of general attentional resources is critical for successful encoding, whereas successful retrieval is particularly reliant on access to a semantic code, making it sensitive to related distractors under DA conditions.

[Attentional impairment in children with attention deficit and hyperactivity disorder].

PubMed

Abbes, Zeineb; Bouden, Asma; Amado, Isabelle; Chantal Bourdel, Marie; Tabbane, Karim; Béchir Halayem, Mohamed

2009-10-01

Attention-deficit hyperactivity disorder (ADHD) is a heterogeneous disorder currently defined by clinical history and behavioral report of impairment. The Attention Network test (ANT) gives measures of different aspects of the complex process of attention. We ask if children with Attention Deficit Hyperactivity Disorder (ADHD) will show a characteristic pattern of deficits on this test. The sample included 40 children (M=9 years) who performed the "Attention network test". Children with an ADHD diagnosis (N=20) were compared to a control group (N=20). The group of children with ADHD showed slower reaction times in all conditions (mean RT=866 ms; SD=234,063). Children with ADHD showed a significant impairment in their executive control system compared to healthy subjects, with slower reaction times in incongruent conditions and lower accuracy scores (RT=1064 ms; F(1.38) p=0.02). Our results showed that spatial orienting and alerting in ADHD was no different than controls (p=0,68). ADHD group showed a greater variable response (p=0,0001). The present study showed that impairment in executive control system and variability measures are the characteristic pattern of deficits in children with ADHD.

Is Animal Age a Factor In the Response of Bone to Spaceflight?

NASA Technical Reports Server (NTRS)

Morey-Holton, E. R.; Garetto, L. P.; Doty, S. B.; Halloran, B. P.; Turner, R. T.; Dalton, Bonnie (Technical Monitor)

2002-01-01

The rodent bone response to spaceflight may be influenced by a multitude of actors including flight duration, strain, and housing. Review of bone formation rates during spaceflight suggests that age may also play a role in the response. Weanling rats show fewer bone changes than older rats. To determine if the long bones of weanling rats were insensitive to weight-bearing, a hindlimb unloading experiment was conducted simultaneously with a 9d shuttle flight in 34d old group-housed male rats. All animals were injected with bone markers 7d and 1d before flight and euthanized at landing, 24hr, and 72hr following recovery. If no differences in body weight, bone length, or bone formation at the tibiofibular junction were noted at the different time points, data were combined for each group. No significant differences in body weight were found at any time period among the groups. The humerus, tibia, and femur elongated significantly during the flight period with no difference in lengths between groups at the end of the flight period. The group-housed flight rats showed no change in cortical bone formation rate compared to preflight values, flight controls, or vivarium controls. However, the hindlimb unloading group showed a significant 30% decrease in bone formation rate compared to all other groups. Individually-housed 38d old animals flown for 14d showed approx. 10% suppression of cortical growth. We speculate that the mechanical threshold required for cross-sectional bone growth is reached in group-house weanling rats during spaceflight, perhaps, through physical interactions, and that the weanling animals are sensitive to loading. However, the threshold is not fully reached in either singly-housed flight or hindlimb unloaded weanling rats. Older singly-housed flight animals appear to show equal or greater bone changes compared to hindlimb unloaded rats. We conclude that age, flight duration, strain, and housing have important roles in rodent skeletal responses to spaceflight.

Biochemical and hematologic changes after short-term space flight

NASA Technical Reports Server (NTRS)

Leach, Carolyn S.

1991-01-01

Clinical laboratory data from blood samples obtained from astronauts before and after 28 flights (average duration = 6 days) of the Space Shuttle were analyzed by the paired t-test and the Wilcoxon signed-rank test and compared with data from the Skylab flights (duration = 28, 56, and 84 days). Angiotensin I and aldosterone were elevated immediately after short-term space flights, but the response of angiotensin I was delayed after Skylab flights. Serum calcium was not elevated after Shuttle flights, but magnesium and uric acid decreased after both Shuttle and Skylab. Creatine phosphokinase in serum was reduced after Shuttle but not Skylab flights, probably because exercises to prevent deconditioning were not performed on the Shuttle. Total cholesterol was unchanged after Shuttle flights, but low density lipoprotein cholesterol increased and high density lipoprotein cholesterol decreased. The concentration of red blood cells was elevated after Shuttle flights and reduced after Skylab flights.

Changes in pituitary growth hormone cells prepared from rats flown on Spacelab 3

NASA Technical Reports Server (NTRS)

Grindeland, R.; Hymer, W. C.; Farrington, M.; Fast, T.; Hayes, C.; Motter, K.; Patil, L.; Vasques, M.

1987-01-01

The effect of exposure to microgravity on pituitary gland was investigated by examining cells isolated from anterior pituitaries of rats flown on the 7-day Spacelab 3 mission and, subsequently, cultured for 6 days. Compared with ground controls, flight cells contained more intracellular growth hormone (GH); however, the flight cells released less GH over the 6-day culture period and after implantation into hypophysectomized rats than did the control cells. Compared with control rats, glands from large rats (400 g) contained more somatotrophs (44 percent compared with 37 percent in control rats); small rats (200 g) showed no difference. No major differences were found in the somatotroph ultrastructure (by TEM) or in the pattern of the immunoactive GH variants. However, high-performance liquid chromatography fractionation of culture media indicated that flight cells released much less of a biologically active high-molecular weight GH variant, suggesting that space flight may lead to secretory dysfunction.

A comparative study of seminiferous tubular epithelium from rats flown on Cosmos 1887 and SL3

NASA Technical Reports Server (NTRS)

Sapp, Walter J.; Williams, Carol S.; Kato, K.; Philpott, Delbert E.; Stevenson, J.; Serova, L. V.

1989-01-01

Space flight, with its unique environmental constraints such as immobilization, decreased and increased pressures, and radiation, is known to affect testicular morphology and spermatogenesis. Among the several biological experiments and animals on board COSMOS 1887 Biosputnik flight were 10 rats, from which were collected testicular tissue. Average weights of flight tests were 6.4 pct. below that of the vivarium control when normalized for weight loss/100 grams body weight. Counts of surviving spermatogonia per tubule cross section indicated an average of 39 spermatogonia for flight animals, 40 for synchronous controls and 44 for the vivarium controls. Serum testosterone was significantly decreased when compared to basal controls but the decrease was not significant when compared in vivarium and synchronous control groups. The significant decrease in spermatogonia and the decrease in serum testosterone are similar to that in animals flown on Space Lab 3 (Challenger Shuttle).

Comparative morphology of the thorax musculature of adult Anisoptera (Insecta: Odonata): Functional aspects of the flight apparatus.

PubMed

Bäumler, Fabian; Gorb, Stanislav N; Büsse, Sebastian

2018-05-02

Due to their unique flight mechanism including a direct flight musculature, Odonata show impressive flight skills. Several publications addressed the details of this flight apparatus like: sclerites, wings, musculature, and flight aerodynamics. However, 3D-analysis of the thorax musculature of adult dragonflies was not studied before and this paper allows for a detailed insight. We, therefore, focused on the thorax musculature of adult Anisoptera using micro-computed tomography. Herewith, we present a comparative morphological approach to identify differences within Anisoptera: Aeshnidae, Corduliidae, Gomphidae, and Libellulidae. In total, 54 muscles were identified: 16 prothoracic, 19 mesothoracic, and 19 metathoracic. Recorded differences were for example, the reduction of muscle Idlm4 and an additional muscle IIIdlm1 in Aeshna cyanea, previously described as rudimentary or missing. Muscle Iscm1, which was previously reported missing in all Odonata, was found in all investigated species. The attachment of muscle IIpcm2 in Pantala flavescens is interpreted as a probable adaption to its long-distance migration behaviour. Furthermore, we present a review of functions of the odonatan flight muscles, considering previous publications. The data herein set a basis for functional and biomechanical studies of the flight apparatus and will therefore lay the foundation for a better understanding of the odonatan flight. Copyright © 2018 Elsevier Ltd. All rights reserved.

Miscarriage among flight attendants.

PubMed

Grajewski, Barbara; Whelan, Elizabeth A; Lawson, Christina C; Hein, Misty J; Waters, Martha A; Anderson, Jeri L; MacDonald, Leslie A; Mertens, Christopher J; Tseng, Chih-Yu; Cassinelli, Rick T; Luo, Lian

2015-03-01

Cosmic radiation and circadian disruption are potential reproductive hazards for flight attendants. Flight attendants from 3 US airlines in 3 cities were interviewed for pregnancy histories and lifestyle, medical, and occupational covariates. We assessed cosmic radiation and circadian disruption from company records of 2 million individual flights. Using Cox regression models, we compared respondents (1) by levels of flight exposures and (2) to teachers from the same cities, to evaluate whether these exposures were associated with miscarriage. Of 2654 women interviewed (2273 flight attendants and 381 teachers), 958 pregnancies among 764 women met study criteria. A hypothetical pregnant flight attendant with median first-trimester exposures flew 130 hours in 53 flight segments, crossed 34 time zones, and flew 15 hours during her home-base sleep hours (10 pm-8 am), incurring 0.13 mGy absorbed dose (0.36 mSv effective dose) of cosmic radiation. About 2% of flight attendant pregnancies were likely exposed to a solar particle event, but doses varied widely. Analyses suggested that cosmic radiation exposure of 0.1 mGy or more may be associated with increased risk of miscarriage in weeks 9-13 (odds ratio = 1.7 [95% confidence interval = 0.95-3.2]). Risk of a first-trimester miscarriage with 15 hours or more of flying during home-base sleep hours was increased (1.5 [1.1-2.2]), as was risk with high physical job demands (2.5 [1.5-4.2]). Miscarriage risk was not increased among flight attendants compared with teachers. Miscarriage was associated with flight attendant work during sleep hours and high physical job demands and may be associated with cosmic radiation exposure.

Role of Corticosteroids in Bone Loss During Space Flight

NASA Technical Reports Server (NTRS)

Wronski, Thomas J.; Halloran, Bernard P.; Miller, Scott C.

1998-01-01

The primary objective of this research project is to test the hypothesis that corticosteroids contribute to the adverse skeletal effects of space flight. To achieve this objective, serum corticosteroids, which are known to increase during space flight, must be maintained at normal physiologic levels in flight rats by a combination of adrenalectomy and corticosteroid supplementation via implanted hormone pellets. Bone analyses in these animals will then be compared to those of intact flight rats that, based on past experience, will undergo corticosteroid excess and bone loss during space flight. The results will reveal whether maintaining serum corticosteroids at physiologic levels in flight rats affects the skeletal abnormalities that normally develop during space flight. A positive response to this question would indicate that the bone loss and decreased bone formation associated with space flight are mediated, at least in part, by corticosteroid excess.

Flight of the Chinese white pine beetle (Coleoptera: Scolytidae) in relation to sex, body weight and energy reserve.

PubMed

Chen, H; Li, Z; Bu, S H; Tian, Z Q

2011-02-01

The flight distance, flight time and individual flight activities of males and females of Dendroctonus armandi were recorded during 96-h flight trials using a flight mill system. The body weight, glucose, glycogen and lipid content of four treatments (naturally emerged, starved, phloem-fed and water-fed) were compared among pre-flight, post-flight and unflown controls. There was no significant difference between males and females in total flight distance and flight time in a given 24-h period. The flight distance and flight time of females showed a significant linear decline as the tethered flying continued, but the sustained flight ability of females was better than that of males. The females had higher glycogen and lipid content than the males; however, there was no significant difference between both sexes in glucose content. Water-feeding and phloem-feeding had significant effects on longevity, survival days and flight potential of D. armandi, which resulted in longer feeding days, poorer flight potential and lower energy substrate content. Our results demonstrate that flight distances in general do not differ between water-fed and starved individuals, whereas phloem-fed females and males fly better than water-fed and starved individuals.

Unification of some biochemical methods of research in the pre- and post-flight periods

NASA Technical Reports Server (NTRS)

Tigranyan, R. A.

1980-01-01

The biochemical methods for determination of various parameters and factors during pre- and post-flight periods, as used by American and Soviet teams dealing with space flight medicine are compared. The emphasis is on the exchange of information on the study of the blood and urine content of space travelers before and after space flight. A series of electrolytic, enzymatic, and hormonal factors is discussed.

Force limits measured on a space shuttle flight

NASA Technical Reports Server (NTRS)

Scharton, T.

2000-01-01

The random vibration forces between a payload and the sidewall of the space shuttle have been measured in flight and compared with the force specifications used in ground vibration tests. The flight data are in agreement with a semi-empirical method, which is widely used to predict vibration test force limits.

Flight Test Validation of Optimal Input Design and Comparison to Conventional Inputs

NASA Technical Reports Server (NTRS)

Morelli, Eugene A.

1997-01-01

A technique for designing optimal inputs for aerodynamic parameter estimation was flight tested on the F-18 High Angle of Attack Research Vehicle (HARV). Model parameter accuracies calculated from flight test data were compared on an equal basis for optimal input designs and conventional inputs at the same flight condition. In spite of errors in the a priori input design models and distortions of the input form by the feedback control system, the optimal inputs increased estimated parameter accuracies compared to conventional 3-2-1-1 and doublet inputs. In addition, the tests using optimal input designs demonstrated enhanced design flexibility, allowing the optimal input design technique to use a larger input amplitude to achieve further increases in estimated parameter accuracy without departing from the desired flight test condition. This work validated the analysis used to develop the optimal input designs, and demonstrated the feasibility and practical utility of the optimal input design technique.

Prediction of unsuppressed jet engine exhaust noise in flight from static data

NASA Technical Reports Server (NTRS)

Stone, J. R.

1980-01-01

A methodology developed for predicting in-flight exhaust noise from static data is presented and compared with experimental data for several unsuppressed turbojet engines. For each engine, static data over a range of jet velocities are compared with the predicted jet mixing noise and shock-cell noise. The static engine noise over and above the jet and shock noises is identified as excess noise. The excess noise data are then empirically correlated to smooth the spectral and directivity relations and account for variations in test conditions. This excess noise is then projected to flight based on the assumption that the only effects of flight are a Doppler frequency shift and a level change given by 40 log (1 - m sub 0 cos theta), where M sub 0 is the flight Mach number and theta is the observer angle relative to the jet axis.

An exploration of function analysis and function allocation in the commercial flight domain

NASA Technical Reports Server (NTRS)

Mcguire, James C.; Zich, John A.; Goins, Richard T.; Erickson, Jeffery B.; Dwyer, John P.; Cody, William J.; Rouse, William B.

1991-01-01

The applicability is explored of functional analysis methods to support cockpit design. Specifically, alternative techniques are studied for ensuring an effective division of responsibility between the flight crew and automation. A functional decomposition is performed of the commercial flight domain to provide the information necessary to support allocation decisions and demonstrate methodology for allocating functions to flight crew or to automation. The function analysis employed 'bottom up' and 'top down' analyses and demonstrated the comparability of identified functions, using the 'lift off' segment of the 'take off' phase as a test case. The normal flight mission and selected contingencies were addressed. Two alternative methods for using the functional description in the allocation of functions between man and machine were investigated. The two methods were compared in order to ascertain their relative strengths and weaknesses. Finally, conclusions were drawn regarding the practical utility of function analysis methods.

Evaluation of constipation in older adults: radioopaque markers (ROMs) versus wireless motility capsule (WMC).

PubMed

Rao, S S C; Coss-Adame, E; Valestin, J; Mysore, K

2012-01-01

There is scarce information regarding assessment of constipation in older subjects. We examined regional and whole-gut transit time (WGTT) with wireless motility capsule (WMC) and compared this with radioopaque markers (ROM) transit. 39 constipated and 11 healthy older subjects (≥ 65 years) ingested a ROM capsule and WMC, wore a data receiver and kept stool diaries for 5 days. WMC recordings were analyzed for colonic transit time (CTT), WGTT and gastric emptying time (GET). Radiographs obtained on day 5 assessed ROM transit. Results for each device were compared. The CTT (p = <0.0001), WGTT (p = <0.001) and GET (p = <0.04) as measured by WMC were all slower in constipated subjects compared to healthy subjects. ROM colonic transit was also slower (p = <0.007) in constipated compared to healthy subjects. The diagnostic utility for identifying subjects with constipation as assessed by receiver operating characteristics were similar; 0.85 (WMC) versus 0.73 (ROM). Device agreement for slow colonic transit was 88% with good correlation between WMC and ROM (CTT r=0.718, p=0.0001, WGTT r=0.693, p=0.0001). Slow transit constipation was identified in 28% with ROM and 32% with WMC. No adverse events were recorded. WMC is a safe and useful device that provides objective diagnosis of delayed colonic and whole gut transit in older constipated adults. It is a radiation-free, physiologic and ambulatory technique that provides additional diagnostic information than ROM. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

THE IMPACT OF NEONATAL BREASTFEEDING ON GROWTH TRAJECTORIES OF YOUTH EXPOSED AND UNEXPOSED TO DIABETES IN UTERO: THE EPOCH STUDY

PubMed Central

Crume, T.L.; Ogden, L.G.; Mayer-Davis, E.J.; Hamman, R.F.; Norris, J.M.; Bischoff, K.J.; McDuffie, R.; Dabelea, D.

2011-01-01

Objective To evaluate the influence of breastfeeding on the body mass index (BMI) growth trajectory from birth through 13 years of age among offspring of diabetic pregnancies (ODP) and offspring of non-diabetic pregnancies (ONDP) participating in the EPOCH study. Subjects There were 94 ODP and 399 ONDP who had multiple BMI measures obtained from birth throughout childhood. A measure of breast milk-months was derived from maternal self-report to categorize breastfeeding status as adequate (≥6 breast milk-months) or low (<6 breast milk-months). Mixed linear effects models were constructed to assess the impact of breastfeeding on the BMI growth curves during infancy (birth to 27 months) and childhood (27 months to 13 years). Results ODP who were adequately breastfed had a slower BMI growth trajectory during childhood (p=0.047) and slower period-specific growth velocity with significant differences between 4 to 6 years of age (p=0.03) and 6 to 9 years of age (p=0.01) compared to ODP with low breastfeeding. A similar pattern was seen in the ONDP, with adequate breastfeeding associated with lower average BMI in infancy (p=0.03) and childhood (p=0.0002) and a slower growth trajectory in childhood (p=0.0002). Slower period-specific growth velocity was seen among the ONDP associated with adequate breastfeeding with significant differences between 12–26 months (p=0.02), 4–6 years (p=0.03), 6–9 years (p=0.0001) and 9–13 years of age (p<.0001). Conclusion Our study provides novel evidence that breastfeeding is associated with long-term effects on childhood BMI growth that extend beyond infancy into early and late childhood. Importantly, these effects are also present in the high-risk offspring, exposed to overnutrition during pregnancy. Breastfeeding in the early postnatal period may represent a critical opportunity to reduce the risk of childhood obesity. PMID:22290537

Neuromuscular performance in the hip joint of elderly fallers and non-fallers.

PubMed

Morcelli, Mary Hellen; LaRoche, Dain Patrick; Crozara, Luciano Fernandes; Marques, Nise Ribeiro; Hallal, Camilla Zamfolini; Rossi, Denise Martineli; Gonçalves, Mauro; Navega, Marcelo Tavella

2016-06-01

Low strength and neuromuscular activation of the lower limbs have been associated with falls making it an important predictor of functional status in the elderly. To compare the rate of neuromuscular activation, rate of torque development, peak torque and reaction time between young and elderly fallers and non-fallers for hip flexion and extension. We evaluated 44 elderly people who were divided into two groups: elderly fallers (n = 20) and elderly non-fallers (n = 24); and 18 young people. The subjects performed three isometric hip flexion and extension contractions. Electromyography data were collected for the rectus femoris, gluteus maximus and biceps femoris muscles. The elderly had 49 % lower peak torque and 68 % lower rate of torque development for hip extension, 28 % lower rate of neuromuscular activation for gluteus maximus and 38 % lower rate of neuromuscular activation for biceps femoris than the young (p < 0.05). Furthermore, the elderly had 42 % lower peak torque and 62 % lower rate of torque development for hip flexion and 48 % lower rate of neuromuscular for rectus femoris than the young (p < 0.05). The elderly fallers showed consistent trend toward a lower rate of torque development than elderly non-fallers for hip extension at 50 ms (29 %, p = 0.298, d = 0.76) and 100 ms (26 %, p = 0.452, d = 0.68).The motor time was 30 % slower for gluteus maximus, 42 % slower for rectus femoris and 50 % slower for biceps femoris in the elderly than in the young. Impaired capacity of the elderly, especially fallers, may be explained by neural and morphological aspects of the muscles. The process of senescence affects the muscle function of the hip flexion and extension, and falls may be related to lower rate of torque development and slower motor time of biceps femoris.

Time to Cooling Is Associated with Resuscitation Outcomes

PubMed Central

Janata, Andreas; Peacock, W. Frank; Deal, Nathan S.; Kalra, Sarathi; Sterz, Fritz

2016-01-01

Our purpose was to analyze evidence related to timing of cooling from studies of targeted temperature management (TTM) after return of spontaneous circulation (ROSC) after cardiac arrest and to recommend directions for future therapy optimization. We conducted a preliminary review of studies of both animals and patients treated with post-ROSC TTM and hypothesized that a more rapid cooling strategy in the absence of volume-adding cold infusions would provide improved outcomes in comparison with slower cooling. We defined rapid cooling as the achievement of 34°C within 3.5 hours of ROSC without the use of volume-adding cold infusions, with a ≥3.0°C/hour rate of cooling. Using the PubMed database and a previously published systematic review, we identified clinical studies published from 2002 through 2014 related to TTM. Analysis included studies with time from collapse to ROSC of 20–30 minutes, reporting of time from ROSC to target temperature and rate of patients in ventricular tachycardia or ventricular fibrillation, and hypothermia maintained for 20–24 hours. The use of cardiopulmonary bypass as a cooling method was an exclusion criterion for this analysis. We compared all rapid cooling studies with all slower cooling studies of ≥100 patients. Eleven studies were initially identified for analysis, comprising 4091 patients. Two additional studies totaling 609 patients were added based on availability of unpublished data, bringing the total to 13 studies of 4700 patients. Outcomes for patients, dichotomized into faster and slower cooling approaches, were determined using weighted linear regression using IBM SPSS Statistics software. Rapid cooling without volume-adding cold infusions yielded a higher rate of good neurological recovery than slower cooling methods. Attainment of a temperature below 34°C within 3.5 hours of ROSC and using a cooling rate of more than 3°C/hour appear to be beneficial. PMID:27906641

On the physics of frequency-domain controlled source electromagnetics in shallow water. 1: isotropic conductivity

NASA Astrophysics Data System (ADS)

Chave, Alan D.; Everett, Mark E.; Mattsson, Johan; Boon, James; Midgley, Jonathan

2017-02-01

In recent years, marine controlled source electromagnetics (CSEM) has found increasing use in hydrocarbon exploration due to its ability to detect thin resistive zones beneath the seafloor. It is the purpose of this paper to evaluate the physics of CSEM for an ocean whose electrical thickness is comparable to or much thinner than that of the overburden using the in-line configuration through examination of the elliptically polarized seafloor electric field, the time-averaged energy flow depicted by the real part of the complex Poynting vector, energy dissipation through Joule heating and the Fréchet derivatives of the seafloor field with respect to the subseafloor conductivity that is assumed to be isotropic. The deep water (ocean layer electrically much thicker than the overburden) seafloor EM response for a model containing a resistive reservoir layer has a greater amplitude and reduced phase as a function of offset compared to that for a half-space, or a stronger and faster response. For an ocean whose electrical thickness is comparable to or much smaller than that of the overburden, the electric field displays a greater amplitude and reduced phase at small offsets, shifting to a stronger amplitude and increased phase at intermediate offsets and a weaker amplitude and enhanced phase at long offsets, or a stronger and faster response that first changes to stronger and slower, and then transitions to weaker and slower. These transitions can be understood by visualizing the energy flow throughout the structure caused by the competing influences of the dipole source and guided energy flow in the reservoir layer, and the air interaction caused by coupling of the entire subseafloor resistivity structure with the sea surface. A stronger and faster response occurs when guided energy flow is dominant, while a weaker and slower response occurs when the air interaction is dominant. However, at intermediate offsets for some models, the air interaction can partially or fully reverse the direction of energy flux in the reservoir layer toward rather than away from the source, resulting in a stronger and slower response. The Fréchet derivatives are dominated by preferential sensitivity to the reservoir layer conductivity for all water depths except at high frequencies, but also display a shift with offset from the galvanic to the inductive mode in the underburden and overburden due to the interplay of guided energy flow and the air interaction. This means that the sensitivity to the horizontal conductivity is almost as strong as to the vertical component in the shallow parts of the subsurface, and in fact is stronger than the vertical sensitivity deeper down. However, the sensitivity to horizontal conductivity is still weak compared to the vertical component within thin resistive regions. The horizontal sensitivity is gradually decreased when the water becomes deep. These observations in part explain the success of shallow towed CSEM using only measurements of the in-line component of the electric field.

Green Flight Challenge

NASA Image and Video Library

2011-09-27

CAFE Foundation Security Chief and Event Manager Bruno Mombrinie, left, talks with CAFE Foundation eCharging Chief Alan Soule as flight crews prepare for the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Linearized aerodynamic and control law models of the X-29A airplane and comparison with flight data

NASA Technical Reports Server (NTRS)

Bosworth, John T.

1992-01-01

Flight control system design and analysis for aircraft rely on mathematical models of the vehicle dynamics. In addition to a six degree of freedom nonlinear simulation, the X-29A flight controls group developed a set of programs that calculate linear perturbation models throughout the X-29A flight envelope. The models include the aerodynamics as well as flight control system dynamics and were used for stability, controllability, and handling qualities analysis. These linear models were compared to flight test results to help provide a safe flight envelope expansion. A description is given of the linear models at three flight conditions and two flight control system modes. The models are presented with a level of detail that would allow the reader to reproduce the linear results if desired. Comparison between the response of the linear model and flight measured responses are presented to demonstrate the strengths and weaknesses of the linear models' ability to predict flight dynamics.

Effet de l'encombrement visuel de l'ecran primaire de vol sur la performance du pilote, la charge de travail et le parcours visuel

NASA Astrophysics Data System (ADS)

Doyon-Poulin, Philippe

Flight deck of 21st century commercial aircrafts does not look like the one the Wright brothers used for their first flight. The rapid growth of civilian aviation resulted in an increase in the number of flight deck instruments and of their complexity, in order to complete a safe and ontime flight. However, presenting an abundance of visual information using visually cluttered flight instruments might reduce the pilot's flight performance. Visual clutter has received an increased interest by the aerospace community to understand the effects of visual density and information overload on pilots' performance. Aerospace regulations demand to minimize visual clutter of flight deck displays. Past studies found a mixed effect of visual clutter of the primary flight display on pilots' technical flight performance. More research is needed to better understand this subject. In this thesis, we did an experimental study in a flight simulator to test the effects of visual clutter of the primary flight display on the pilot's technical flight performance, mental workload and gaze pattern. First, we identified a gap in existing definitions of visual clutter and we proposed a new definition relevant to the aerospace community that takes into account the context of use of the display. Then, we showed that past research on the effects of visual clutter of the primary flight display on pilots' performance did not manipulate the variable of visual clutter in a similar manner. Past research changed visual clutter at the same time than the flight guidance function. Using a different flight guidance function between displays might have masked the effect of visual clutter on pilots' performance. To solve this issue, we proposed three requirements that all tested displays must satisfy to assure that only the variable of visual clutter is changed during study while leaving other variables unaffected. Then, we designed three primary flight displays with a different visual clutter level (low, medium, high) but with the same flight guidance function, by respecting the previous requirements. Twelve pilots, with a mean experience of over 4000 total flight hours, completed an instrument landing in a flight simulator using all three displays for a total of nine repetitions. Our results showed that pilots reported lower workload level and had better lateral precision during the approach using the medium-clutter display compared to the low- and high-clutter displays. Also, pilots reported that the medium-clutter display was the most useful for the flight task compared to the two other displays. Eye tracker results showed that pilots' gaze pattern was less efficient for the high-clutter display compared to the low- and medium-clutter displays. Overall, these new experimental results emphasize the importance of optimizing visual clutter of flight displays as it affects both objective and subjective performance of experienced pilots in their flying task. This thesis ends with practical recommendations to help designers optimize visual clutter of displays used for man-machine interface.

A review of some head-up display formats. [tests on sensing equipment for flights following partly visible terrain close to the ground

NASA Technical Reports Server (NTRS)

Naish, J. M.

1979-01-01

Two alternate head-up display devices (HUD) were compared for properties relevant to the accurate performance of concurrent tasks in real flight conditions and in various flight modes. The comparisons were made to find the disorientation resistance of the HUDs along with the tracking accuracy, interference resistance, fixation resistance, and error resistance. The use of displacement and flight path information for vertical control is discussed in terms of flight stability. Several combinations of symbols and driving signals are described, including a compensated control law, which were used in simulated flight to deal with wind shear.

Real-Time Aerodynamic Parameter Estimation without Air Flow Angle Measurements

NASA Technical Reports Server (NTRS)

Morelli, Eugene A.

2010-01-01

A technique for estimating aerodynamic parameters in real time from flight data without air flow angle measurements is described and demonstrated. The method is applied to simulated F-16 data, and to flight data from a subscale jet transport aircraft. Modeling results obtained with the new approach using flight data without air flow angle measurements were compared to modeling results computed conventionally using flight data that included air flow angle measurements. Comparisons demonstrated that the new technique can provide accurate aerodynamic modeling results without air flow angle measurements, which are often difficult and expensive to obtain. Implications for efficient flight testing and flight safety are discussed.

Statistical analysis of flight times for space shuttle ferry flights

NASA Technical Reports Server (NTRS)

Graves, M. E.; Perlmutter, M.

1974-01-01

Markov chain and Monte Carlo analysis techniques are applied to the simulated Space Shuttle Orbiter Ferry flights to obtain statistical distributions of flight time duration between Edwards Air Force Base and Kennedy Space Center. The two methods are compared, and are found to be in excellent agreement. The flights are subjected to certain operational and meteorological requirements, or constraints, which cause eastbound and westbound trips to yield different results. Persistence of events theory is applied to the occurrence of inclement conditions to find their effect upon the statistical flight time distribution. In a sensitivity test, some of the constraints are varied to observe the corresponding changes in the results.

Developmental hearing loss impedes auditory task learning and performance in gerbils.

PubMed

von Trapp, Gardiner; Aloni, Ishita; Young, Stephen; Semple, Malcolm N; Sanes, Dan H

2017-04-01

The consequences of developmental hearing loss have been reported to include both sensory and cognitive deficits. To investigate these issues in a non-human model, auditory learning and asymptotic psychometric performance were compared between normal hearing (NH) adult gerbils and those reared with conductive hearing loss (CHL). At postnatal day 10, before ear canal opening, gerbil pups underwent bilateral malleus removal to induce a permanent CHL. Both CHL and control animals were trained to approach a water spout upon presentation of a target (Go stimuli), and withhold for foils (Nogo stimuli). To assess the rate of task acquisition and asymptotic performance, animals were tested on an amplitude modulation (AM) rate discrimination task. Behavioral performance was calculated using a signal detection theory framework. Animals reared with developmental CHL displayed a slower rate of task acquisition for AM discrimination task. Slower acquisition was explained by an impaired ability to generalize to newly introduced stimuli, as compared to controls. Measurement of discrimination thresholds across consecutive testing blocks revealed that CHL animals required a greater number of testing sessions to reach asymptotic threshold values, as compared to controls. However, with sufficient training, CHL animals approached control performance. These results indicate that a sensory impediment can delay auditory learning, and increase the risk of poor performance on a temporal task. Copyright © 2016 Elsevier B.V. All rights reserved.

Demonstrating a Nutritional Advantage to the Fast-Cooking Dry Bean (Phaseolus vulgaris L.).

PubMed

Wiesinger, Jason A; Cichy, Karen A; Glahn, Raymond P; Grusak, Michael A; Brick, Mark A; Thompson, Henry J; Tako, Elad

2016-11-16

Dry beans (Phaseolus vulgaris L.) are a nutrient-dense food rich in protein and micronutrients. Despite their nutritional benefits, long cooking times limit the consumption of dry beans worldwide, especially in nations where fuelwood for cooking is often expensive or scarce. This study evaluated the nutritive value of 12 dry edible bean lines that vary for cooking time (20-89 min) from four market classes (yellow, cranberry, light red kidney, and red mottled) of economic importance in bean-consuming regions of Africa and the Americas. When compared to their slower cooking counterparts within each market class, fast-cooking dry beans retain more protein and minerals while maintaining similar starch and fiber densities when fully cooked. For example, some of the highest protein and mineral retention values were measured in the fast-cooking yellow bean cultivar Cebo Cela, which offered 20% more protein, 10% more iron, and 10% more zinc with each serving when compared with Canario, a slow-cooking yellow bean that requires twice the cooking time to become palatable. A Caco-2 cell culture model also revealed the bioavailability of iron is significantly higher in faster cooking entries (r = -0.537, P = 0.009) as compared to slower cooking entries in the same market class. These findings suggest that fast-cooking bean varieties have improved nutritive value through greater nutrient retention and improved iron bioavailability.

Effect of modified atmosphere packaging and temperature abuse on flavor related volatile compounds of rocket leaves (Diplotaxis tenuifolia L.).

PubMed

Mastrandrea, Leonarda; Amodio, Maria Luisa; Pati, Sandra; Colelli, Giancarlo

2017-07-01

The effect of storage conditions on flavor-related volatile composition of wild rocket ( Diplotaxis tenuifolia ) was investigated on Modified Atmosphere packed (MAP) leaves stored under isothermal and non-isothermal conditions. In a first experiment the effect of MAP was compared to the storage in air at 5 °C; a second experiment aimed to study the effect of non isothermal conditions, with two temperature abuses (at 13 °C for 24 h) during a 5 °C. Twenty-four volatiles were detected, including C6, C5, isothiocyanate, lipid-derived and sulfur compounds. In the first experiment, MAP-stored rocket showed a slower loss of typical flavour volatiles (thiocyanates and isothiocyanates) and a slower production of off-flavors until 6 days of storage, compared to leaves stored in air. After this time, dimethyl sulfide and acetaldehyde dramatically increased in MAP-stored rocket samples. In the second experiment, samples stored under non-isothermal conditions showed lower O 2 and higher CO 2 concentrations than samples stored under isothermal conditions. Rocket leaves stored under non-isothermal conditions showed an increased production of volatiles responsible of off-flavors (acetaldehyde and dimethyl sulfide) following temperature abuse comparing to storage in isothermal condition. Thus, dimethyl sulfide and acetaldehyde could be effective markers for tracking the effect of temperature fluctuations on rocket during storage.

Exercise Countermeasures for Bone Loss During Space Flight: A Method for the Study of Ground Reaction Forces and Their Implications for Bone Strain

NASA Technical Reports Server (NTRS)

Peterman, M.; McCrory, J. L.; Sharkey, N. A.; Piazza, S.; Cavanagh, P. R.

1999-01-01

The human zero-gravity locomotion simulator and the cadaver simulator offer a powerful combination for the study of the implications of exercise for maintaining bone quality during space flight. Such studies, when compared with controlled in-flight exercise programs, could help in the identification of a strain threshold for the prevention of bone loss during space flight.

Evaluation of the Malcolm horizon in a moving-base flight simulator

NASA Technical Reports Server (NTRS)

Gillingham, K. K.

1984-01-01

The efficacy of the Malcolm Horizon (MH) in a controlled, simulated, instrument flight environment was examined. Eight flight parameters were used to compare performance under experimental and control conditions. The parameters studied were pitch attitude, roll attitude, turn rate, airspeed, vertical velocity, heading, altitude, and course deviation. Testing of a commercial realization of the MH concept in a flight simulator revealed strengths and weaknesses of the currently available MH hardware.

KC-135 Winglet Program Review

NASA Technical Reports Server (NTRS)

1982-01-01

The results of a joint NASA/USAF program to develop flight test winglets on a KC-135 aircraft are reviewed. The winglet development from concept through wind tunnel and flight tests is discussed. Predicted, wind tunnel, and flight test results are compared for the performance, loads and flutter characteristics of the winglets. The flight test winglets had a variable winglet cant and incidence angle capability which enabled a limited evaluation of the effects of these geometry changes.

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The e-Genius aircraft prepares to takeoff for the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The PhoEnix aircraft prepares to takeoff for the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The Pipistrel-USA, Taurus G4 aircraft prepares to takeoff for the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The e-Genius aircraft is pulled out to the runway for the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

Media and ground crew look at aircraft as they participate in the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Rat gestation during space flight: outcomes for dams and their offspring born after return to Earth.

PubMed

Wong, A M; DeSantis, M

1997-01-01

Sprague-Dawley rats were studied to learn whether gestation in the near-zero gravity, high radiation environment of space impacts selected mammalian postnatal events. Ten rats spent days nine to twenty of pregnancy aboard the space shuttle orbiter Atlantis (STS-66). Their movement was studied shortly after return to Earth; subsequently, several of their offspring were cross-fostered and examined through postnatal day 81 (P81) for whole body growth and somatic motor development. Values for the flight animals were compared to ground-based control groups. Relative to controls, the pregnant flight rats showed a marked paucity of locomotion during the first few hours after returning to Earth. There was greater likelihood of perinatal morbidity for the offspring of flight dams when compared to the control groups. Whole body weight of surviving offspring, averaged for each group separately, showed typical sigmoidal growth curves when plotted against postnatal age. The flight group for our study had a larger ratio of female to male pups, and that was sufficient to account for the lower average daily weight gained by the flight animals when compared to the control groups. Walking was universally achieved by P13 and preceded eye opening, which was complete in all pups by P17. Thus, both of these developmental horizons were attained on schedule in the flight as well as the control rats. Characteristic changes were observed in hind limb step length and gait width as the pups grew. These patterns occurred at the same time in each group of rats. Therefore, prenatal space flight from days nine to twenty of gestation did not interfere with the establishment of normal patterns for hind paw placement during walking.

Rat Gestation During Space Flight: Outcomes for Dams and Their Offspring Born After Return to Earth

NASA Technical Reports Server (NTRS)

Wong, Andre M.; DeSantis, Mark

1997-01-01

Sprague-Dawley rats were studied to learn whether gestation in the near-zero gravity, high radiation environment of space impacts selected mammalian postnatal events. Ten rats spent days nine to twenty of pregnancy aboard the space shuttle orbiter Atlantis (STS-66). Their movement was studied shortly after return to Earth; subsequently, several of their offspring were cross-fostered and examined through postnatal day 81 (P81) for whole body growth and somatic motor development. Values for the flight animals were compared to ground-based control groups. Relative to controls, the pregnant flight rats showed a marked paucity of locomotion during the first few hours after returning to Earth. There was greater likelihood of perinatal morbidity for the offspring of flight dams when compared to the control groups. Whole body weight of surviving offspring, averaged for each group separately, showed typical sigmoidal growth curves when plotted against postnatal age. The flight group for our study had a larger ratio of female to male pups, and that was sufficient to account for the lower average daily weight gained by the flight animals when compared to the control groups. Walking was universally achieved by P13 and preceded eye opening, which was complete in all pups by P17. Thus, both of these developmental horizons were attained on schedule in the flight as well as the control rats. Characteristic changes were observed in hind limb step length and gait width as the pups grew. These patterns occurred at the same time in each group of rats. Therefore, prenatal space flight from days nine to twenty of gestation did not interfere with the establishment of normal patterns for hind paw placement during walking.

NSTA-NASA Shuttle Student Involvement Project. Experiment Results: Insect Flight Observation at Zero Gravity

NASA Technical Reports Server (NTRS)

Nelson, T. E.; Peterson, J. R.

1982-01-01

The flight responses of common houseflies, velvetbean caterpillar moths, and worker honeybees were observed and filmed for a period of about 25 minutes in a zero-g environment during the third flight of the Space Shuttle Vehicle (flight number STS-3; March 22-30, 1982). Twelve fly puparia, 24 adult moths, 24 moth pupae, and 14 adult bees were loaded into an insect flight box, which was then stowed aboard the Shuttle Orbiter, the night before the STS-3 launch at NASA's Kennedy Space Center (KSC). The main purpose of the experiment was to observe and compare the flight responses of the three species of insects, which have somewhat different flight control mechanisms, under zero-g conditions.

Flight effects on noise generated by the JT8D-17 engine in a quiet nacelle and a conventional nacelle as measured in the NASA-Ames 40- by 80-foot wind tunnel

NASA Technical Reports Server (NTRS)

Strout, F. G.

1976-01-01

A JT8D-17 turbofan engine was tested in the NASA-Ames 40- by 80-foot wind tunnel to determine flight effects on jet and fan noise. Baseline, quiet nacelle with 20-lobe ejector/suppressor, and internal mixer configurations were tested over a range of engine power settings and tunnel velocities. Flight effects derived from the 40- by 80-foot wind tunnel test are compared with 727/JT8D flight test data and with model data obtained in a smaller wind tunnel. Procedures are defined for measuring noise data in a wind tunnel relatively near the sources and analyzing the results to obtain far-field flight effects. Wind tunnel and 727 flight test noise results compare favorably for both the baseline and quiet nacelle configurations. Two reports are provided, including a comprehensive version with extensive test results and analysis and the subject summary version that emphasizes data analysis and program finding.

Flight Performance During Exposure to Acute Hypobaric Hypoxia.

PubMed

Steinman, Yuval; van den Oord, Marieke H A H; Frings-Dresen, Monique H W; Sluiter, Judith K

2017-08-01

The purpose of the present study was to examine the influence of hypobaric hypoxia (HH) on a pilot's flight performance during exposure to simulated altitudes of 91, 3048, and 4572 m (300, 10,000, and 15,000 ft) and to monitor the pilot's physiological reactions. In a single-blinded counter-balanced design, 12 male pilots were exposed to HH while flying in a flight simulator that had been placed in a hypobaric chamber. Flight performance of the pilots, pilot's alertness level, Spo2, heart rate (HR), minute ventilation (VE), and breathing frequency (BF) were measured. A significant difference was found in Flight Profile Accuracy (FPA) between the three altitudes. Post hoc analysis showed no significant difference in performance between 91 m and 3048 m. A trend was observed at 4572 m, suggesting a decrease in flight performance at that altitude. Significantly lower alertness levels were observed at the start of the flight at 4572 m compared to 91 m, and at the end of the flight at 4572 m compared to the start at that altitude. Spo2 and BF decreased, and HR increased significantly with altitude. The present study did not provide decisive evidence for a decrease in flight performance during exposure to simulated altitudes of 3048 and 4572 m. However, large interindividual variation in pilots' flight performance combined with a gradual decrease in alertness levels observed in the present study puts into question the ability of pilots to safely fly an aircraft while exposed to these altitudes without supplemental oxygen.Steinman Y, van den Oord MHAH, Frings-Dresen MHW, Sluiter JK. Flight performance during exposure to acute hypobaric hypoxia. Aerosp Med Hum Perform. 2017; 88(8):760-767.

Miscarriage Among Flight Attendants

PubMed Central

Grajewski, Barbara; Whelan, Elizabeth A.; Lawson, Christina C.; Hein, Misty J.; Waters, Martha A.; Anderson, Jeri L.; MacDonald, Leslie A.; Mertens, Christopher J.; Tseng, Chih-Yu; Cassinelli, Rick T.; Luo, Lian

2015-01-01

Background Cosmic radiation and circadian disruption are potential reproductive hazards for flight attendants. Methods Flight attendants from 3 US airlines in 3 cities were interviewed for pregnancy histories and lifestyle, medical, and occupational covariates. We assessed cosmic radiation and circadian disruption from company records of 2 million individual flights. Using Cox regression models, we compared respondents (1) by levels of flight exposures and (2) to teachers from the same cities, to evaluate whether these exposures were associated with miscarriage. Results Of 2654 women interviewed (2273 flight attendants and 381 teachers), 958 pregnancies among 764 women met study criteria. A hypothetical pregnant flight attendant with median firsttrimester exposures flew 130 hours in 53 flight segments, crossed 34 time zones, and flew 15 hours during her home-base sleep hours (10 pm–8 am), incurring 0.13 mGy absorbed dose (0.36 mSv effective dose) of cosmic radiation. About 2% of flight attendant pregnancies were likely exposed to a solar particle event, but doses varied widely. Analyses suggested that cosmic radiation exposure of 0.1 mGy or more may be associated with increased risk of miscarriage in weeks 9–13 (odds ratio = 1.7 [95% confidence interval = 0.95–3.2]). Risk of a first-trimester miscarriage with 15 hours or more of flying during home-base sleep hours was increased (1.5 [1.1–2.2]), as was risk with high physical job demands (2.5 [1.5–4.2]). Miscarriage risk was not increased among flight attendants compared with teachers. Conclusions Miscarriage was associated with flight attendant work during sleep hours and high physical job demands and may be associated with cosmic radiation exposure. PMID:25563432

Ares I-X Separation and Reentry Trajectory Analyses

NASA Technical Reports Server (NTRS)

Tartabini, Paul V.; Starr, Brett R.

2011-01-01

The Ares I-X Flight Test Vehicle was launched on October 28, 2009 and was the first and only test flight of NASA s two-stage Ares I launch vehicle design. The launch was successful and the flight test met all of its primary and secondary objectives. This paper discusses the stage separation and reentry trajectory analysis that was performed in support of the Ares I-X test flight. Pre-flight analyses were conducted to assess the risk of stage recontact during separation, to evaluate the first stage flight dynamics during reentry, and to define the range safety impact ellipses of both stages. The results of these pre-flight analyses were compared with available flight data. On-board video taken during flight showed that the flight test vehicle successfully separated without any recontact. Reconstructed trajectory data also showed that first stage flight dynamics were well characterized by pre-flight Monte Carlo results. In addition, comparisons with flight data indicated that the complex interference aerodynamic models employed in the reentry simulation were effective in capturing the flight dynamics during separation. Finally, the splash-down locations of both stages were well within predicted impact ellipses.

Effect of Sampling Schedule on Pharmacokinetic Parameter Estimates of Promethazine in Astronauts

NASA Technical Reports Server (NTRS)

Boyd, Jason L.; Wang, Zuwei; Putcha, Lakshmi

2005-01-01

Six astronauts on the Shuttle Transport System (STS) participated in an investigation on the pharmacokinetics of promethazine (PMZ), a medication used for the treatment of space motion sickness (SMS) during flight. Each crewmember completed the protocol once during flight and repeated thirty days after returned to Earth. Saliva samples were collected at scheduled times for 72 h after PMZ administration; more frequent samples were collected on the ground than during flight owing to schedule constraints in flight. PMZ concentrations in saliva were determined by a liquid chromatographic/mass spectrometric (LC-MS) assay and pharmacokinetic parameters (PKPs) were calculated using actual flight and ground-based data sets and using time-matched sampling schedule on ground to that during flight. Volume of distribution (V(sub c)) and clearance (Cl(sub s),) decreased during flight compared to that from time-matched ground data set; however, Cl(sub s) and V(sub c) estimates were higher for all subjects when partial ground data sets were used for analysis. Area under the curve (AUC) normalized with administered dose was similar in flight and partial ground data; however AUC was significantly lower using time-matched sampling compared with the full data set on ground. Half life (t(sub 1/2)) was longest during flight, shorter with matched-sampling schedule on ground and shortest when complete data set from ground was used. Maximum concentration (C(sub max)), time for C(sub max), (t(sub max)), parameters of drug absorption, depicted a similar trend with lowest and longest respectively, during flight, lower with time-matched ground data and highest and shortest with full ground data.

[Effects of parabolic flight on redox status in SH-SY5Y cells].

PubMed

Bi, Lei; Qu, Li-Na; Huang, Zeng-Ming; Wang, Chun-Yan; Li, Qi; Tan, Ying-Jun; Li, Ying-Hui

2009-10-25

Space flight is known to produce a number of neurological disturbances. The etiology is unknown, but it may involve increased oxidative stress. A line of experimental evidence indicates that space flight may disrupt antioxidant defense system and result in increased oxidative stress. In vitro studies found that abundant of NO was produced in rat pheochromocytoma (PC12) cells, SHSY5Y neuroblastoma cells, and protein nitration was increased in PC12 cells within a simulated microgravity rotating wall bioreactor high aspect ratio vessel system or clinostat system. In the present study, we observed the change of redox status in SH-SY5Y cells after parabolic flight, and studied the effects of key redox molecule, thioredoxin (TRX), during the altered gravity. SH-SY5Y cells were divided into four groups: control cells, control cells transfected with TRX, flight cells and flight cells transfected with TRX. The expression levels of 3-nitrotyrosine (3-NT), inducible nitric oxide synthase (iNOS), TRX and thioredoxin reductase (TRXR) were observed by immunocytochemical method. It was shown that after parabolic flight, the staining of 3-NT and TRX were enhanced, while the expression level of TRXR was down-regulated compared with control. As for flight cells transfected with TRX, the staining of 3-NT and iNOS were weakened compared with flight cells. These results obtained suggest that altered gravity may increase protein nitration, down-regulate TRXR and elicit oxidative stress in SH-SY5Y cells, while TRX transfection could partly protect cells against oxidative stress induced by parabolic flight.

Effect of sampling schedule on pharmacokinetic parameter estimates of promethazine in astronauts

NASA Astrophysics Data System (ADS)

Boyd, Jason L.; Wang, Zuwei; Putcha, Lakshmi

2005-08-01

Six astronauts on the Shuttle Transport System (STS) participated in an investigation on the pharmacokinetics of promethazine (PMZ), a medication used for the treatment of space motion sickness (SMS) during flight. Each crewmember completed the protocol once during flight and repeated thirty days after returned to Earth. Saliva samples were collected at scheduled times for 72 h after PMZ administration; more frequent samples were collected on the ground than during flight owing to schedule constraints in flight. PMZ concentrations in saliva were determined by a liquid chromatographic/mass spectrometric (LC-MS) assay and pharmacokinetic parameters (PKPs) were calculated using actual flight and ground-based data sets and using time-matched sampling schedule on ground to that during flight. Volume of distribution (Vc) and clearance (Cls) decreased during flight compared to that from time-matched ground data set; however, ClS and Vc estimates were higher for all subjects when partial ground data sets were used for analysis. Area under the curve (AUC) normalized with administered dose was similar in flight and partial ground data; however AUC was significantly lower using time-matched sampling compared with the full data set on ground. Half life (t1/2) was longest during flight, shorter with matched-sampling schedule on ground and shortest when complete data set from ground was used. Maximum concentration (Cmax), time for Cmax (tmax), parameters of drug absorption, depicted a similar trend with lowest and longest respectively, during flight, lower with time- matched ground data and highest and shortest with full ground data.

Learning to Count: Structured Practice with Spatial Cues Supports the Development of Counting Sequence Knowledge in 3-Year-Old English-Speaking Children

ERIC Educational Resources Information Center

Dunbar, Kristina; Ridha, Aala; Cankaya, Ozlem; Jiménez Lira, Carolina; LeFevre, Jo-Anne

2017-01-01

Research Findings: Children who speak English are slower to learn the counting sequence between 11 and 20 compared to children who speak Asian languages. In the present research, we examined whether providing children with spatially relevant information during counting would facilitate their acquisition of the counting sequence. Three-year-olds…

2012 Year-End Poll of Employers: A Look at Hiring and Salary Projections for the Coming Year. Summary Report

ERIC Educational Resources Information Center

Estrada, Rebecca; Schoenfeld, Gregg

2012-01-01

Employers across the globe project a slightly more positive hiring outlook for 2013 compared with 2012, according to responses to the 2012 Year-End Poll of Employers of the Graduate Management Admission Council (GMAC). Hiring decisions in 2012 were influenced by a mixture of economic conditions from the unfolding Eurozone crisis, to slower growth…

Oral Gabapentin for Photorefractive Keratectomy Pain

DTIC Science & Technology

2011-02-01

keratomileusis ( LASIK ) is the predomi- nant procedure of choice for most patients and surgeons, photorefractive keratectomy (PRK) remains a viable...thus have an increased risk for LASIK flap dislocation.2,3 Although slower visual recovery, prolonged use of topical steroidal agents, and...postoperative corneal haze are considered drawbacks to PRK compared with LASIK ,4,5 the primary disadvantage of PRK is postoperative pain. Topical and oral

Post-Flight Analysis of the Guidance, Navigation, and Control Performance During Orion Exploration Flight Test 1

NASA Technical Reports Server (NTRS)

Barth, Andrew; Mamich, Harvey; Hoelscher, Brian

2015-01-01

The first test flight of the Orion Multi-Purpose Crew Vehicle presented additional challenges for guidance, navigation and control as compared to a typical re-entry from the International Space Station or other Low Earth Orbit. An elevated re-entry velocity and steeper flight path angle were chosen to achieve aero-thermal flight test objectives. New IMU's, a GPS receiver, and baro altimeters were flight qualified to provide the redundant navigation needed for human space flight. The guidance and control systems must manage the vehicle lift vector in order to deliver the vehicle to a precision, coastal, water landing, while operating within aerodynamic load, reaction control system, and propellant constraints. Extensive pre-flight six degree-of-freedom analysis was performed that showed mission success for the nominal mission as well as in the presence of sensor and effector failures. Post-flight reconstruction analysis of the test flight is presented in this paper to show whether that all performance metrics were met and establish how well the pre-flight analysis predicted the in-flight performance.

Pulmonary O2 uptake on-kinetics in endurance- and sprint-trained master athletes.

PubMed

Berger, N J A; Rittweger, J; Kwiet, A; Michaelis, I; Williams, A G; Tolfrey, K; Jones, A M

2006-12-01

The purpose of this study was to characterise the VO2 kinetic response to moderate intensity cycle exercise in endurance-trained (END) and sprint or power-trained (SPR) track and field master athletes ranging in age from 45 to 85 years. We hypothesised that the time constant (tau) describing the Phase II VO2 on-response would be smaller in the END compared to the SPR athletes, and that the tau would become greater with increasing age in both groups. Eighty-four master athletes who were competing at either the British or European Veteran Athletics Championships acted as subjects, and were classified as either END (800 m - marathon; n = 41), or SPR (100 - 400 m and field events; n = 43) specialists. Subjects completed two 6 minute "step" transitions to a work rate of moderate intensity on a cycle ergometer and pulmonary gas exchange was measured breath-by-breath. Analysis of variance revealed that SPR athletes had slower VO2 on-kinetics (i.e., greater tau) compared to END athletes at each of the age groups studied: 46 - 55 yrs (END: 25 +/- 6 vs. SPR: 36 +/- 9 s; p < 0.10), 56 - 65 yrs (END: 25 +/- 5 vs. SPR: 35 +/- 10 s; p < 0.05), 66 - 75 yrs (END: 29 +/- 10 vs. SPR: 40 +/- 13 s; p < 0.05), and 76 - 85 yrs (END: 31 +/- 10 vs. SPR: 51 +/- 18 s; p < 0.05). The VO2 on-kinetics became slower with advancing age in the SPR athletes (p < 0.05 between 56 - 65 and 76 - 85 yrs) but were not significantly changed in the END athletes. The slower VO2 on-kinetics in SPR compared to END master athletes is consistent both with differences in physiology (e.g., muscle fibre type, oxidative/glycolytic capacity) and training between these specialist athletes. Master END athletes have similar tau values to their younger counterparts (approximately 25 s) suggesting that participation in endurance exercise training limits the slowing of VO2 on-kinetics with age in this population.

Does public transport use prevent declines in walking speed among older adults living in England? A prospective cohort study

PubMed Central

Rouxel, Patrick; Webb, Elizabeth; Chandola, Tarani

2017-01-01

Objectives Although there is some evidence that public transport use confers public health benefits, the evidence is limited by cross-sectional study designs and health-related confounding factors. This study examines the effect of public transport use on changes in walking speed among older adults living in England, comparing frequent users of public transport to their peers who did not use public transport because of structural barriers (poor public transport infrastructure) or through choice. Design Prospective cohort study. Setting England, UK. Participants Older adults aged ≥60 years eligible for the walking speed test. 6246 individuals at wave 2 (2004–2005); 5909 individuals at wave 3 (2006–2007); 7321 individuals at wave 4 (2008–2009); 7535 individuals at wave 5 (2010–2011) and 7664 individuals at wave 6 (2012–2013) of the English Longitudinal Study of Ageing. Main outcome measure The walking speed was estimated from the time taken to walk 2.4 m. Fixed effects models and growth curve models were used to examine the associations between public transport use and walking speed. Results Older adults who did not use public transport through choice or because of structural reasons had slower walking speeds (−0.02 m/s (95% CI −0.03 to –0.003) and −0.02 m/s (95% CI −0.03 to –0.01), respectively) and took an extra 0.07 s to walk 2.4 m compared with their peers who used public transport frequently. The age-related trajectories of decline in walking speed were slower for frequent users of public transport compared with non-users. Conclusions Frequent use of public transport may prevent age-related decline in physical capability by promoting physical activity and lower limb muscle strength among older adults. The association between public transport use and slower decline in walking speed among older adults is unlikely to be confounded by health-related selection factors. Improving access to good quality public transport could improve the health of older adults. PMID:28963309

Marked exacerbation of orthostatic intolerance after long- vs. short-duration spaceflight in veteran astronauts.

PubMed

Meck, J V; Reyes, C J; Perez, S A; Goldberger, A L; Ziegler, M G

2001-01-01

The incidence of postflight orthostatic intolerance after short-duration spaceflight is about 20%. However, the incidence after long-duration spaceflight was unknown. The purpose of this study was to test the hypothesis that orthostatic intolerance is more severe after long-duration than after short-duration flight. We performed tilt tests on six astronauts before and after long-duration (129-190 days) spaceflights and compared these data with data obtained during stand tests before and after previous short-duration missions. Five of the six astronauts studied became presyncopal during tilt testing after long-duration flights. Only one had become presyncopal during stand testing after short-duration flights. We also compared the long-duration flight tilt test data to tilt test data from 20 different astronauts who flew on the short-duration Shuttle missions that delivered and recovered the astronauts to and from the Mir Space Station. Five of these 20 astronauts became presyncopal on landing day. Heart rate responses to tilt were no different between astronauts on long-duration flights and astronauts on short-duration flights, but long-duration subjects had lower stroke volumes and cardiac outputs than short-duration presyncopal subjects, suggesting a possible decrease in cardiac contractile function. One subject had subnormal norepinephrine release with upright posture after the long flight but not after the short flight. Plasma volume losses were not greater after long flights. Long-duration spaceflight markedly increases orthostatic intolerance, probably with multiple contributing factors.

Animal Enclosure Module (AEM)

NASA Technical Reports Server (NTRS)

1998-01-01

The primary objective of this research project is to test the hypothesis that corticosteroids contribute to the adverse skeletal effects of space flight. To achieve this objective, serum corticosteroids, which are known to increase during space flight, must be maintained at normal physiologic levels in flight rats by a combination of adrenalectomy and corticosteroid supplementation via implanted hormone pellets. Bone analyses in these animals will then be compared to those of intact flight rats that, based on past experience, will undergo corticosteroid excess and bone loss during space flight. The results will reveal whether maintaining serum corticosteroids at physiologic levels in flight rats affects the skeletal abnormalities that normally develop during space flight. A positive response to this question would indicate that the bone loss and decreased bone formation associated with space flight are mediated, at least in part, by corticosteroid excess.

STS-1 operational flight profile. Volume 5: Descent, cycle 3. Appendix C: Monte Carlo dispersion analysis

NASA Technical Reports Server (NTRS)

1980-01-01

The results of three nonlinear the Monte Carlo dispersion analyses for the Space Transportation System 1 Flight (STS-1) Orbiter Descent Operational Flight Profile, Cycle 3 are presented. Fifty randomly selected simulation for the end of mission (EOM) descent, the abort once around (AOA) descent targeted line are steep target line, and the AOA descent targeted to the shallow target line are analyzed. These analyses compare the flight environment with system and operational constraints on the flight environment and in some cases use simplified system models as an aid in assessing the STS-1 descent flight profile. In addition, descent flight envelops are provided as a data base for use by system specialists to determine the flight readiness for STS-1. The results of these dispersion analyses supersede results of the dispersion analysis previously documented.

Heat stress and carbon monoxide exposure during C-130 vehicle transportation.

PubMed

Dor, Alex; Pokroy, Russell; Goldstein, Liav; Barenboim, Erez; Zilberberg, Michal

2005-04-01

Running gasoline engines in a confined space causes heat stress and carbon monoxide (CO) buildup. Loading the C-130 aircraft by driving the vehicles onto the platform may expose the C-130 cabin crew to these environmental hazards. This study was aimed at investigating heat stress and CO exposure in the C-130 cabin during vehicle airlift. There were four summer flights (two two-vehicle, two three-vehicle; 2 d, 2 nights) studied. The cabin heat stress index (wet bulb globe temperature, WBGT) and CO levels before vehicle loading (control) were compared with those after vehicle loading. Furthermore, two- and three-vehicle transportations, as well as day and night transportations, were compared. Ground temperature ranged from 18.2 to 33.4 degrees C. Mean heat stress index was higher in vehicle transportation than control flights, the greatest difference being 5.9 degrees C (p < 0.001). The WBGT levels exceeded the recommended exposure limit in 28 of 38 measurements during day flights. The cabin heat stress increased sharply with vehicle loading, and continued to increase for a range of 60-140 min after loading. Elevated cabin CO levels were found in three-vehicle flights as compared with two, and in night flights as compared with day. In hot climates, C-130 vehicle transportation may exacerbate heat stress. The in-flight heat stress can be predicted by the ambient temperature, duration of the vehicle transportation, and number of transported vehicles. The cabin CO level is related to the number of transported vehicles. We recommend the use of effective environmental control systems during C-130 vehicle transportation in hot climates.

Time Resolved Studies of Carrier Dynamics in III -v Heterojunction Semiconductors.

NASA Astrophysics Data System (ADS)

Westland, Duncan James

Available from UMI in association with The British Library. Requires signed TDF. Picosecond time-resolution photoluminescence spectroscopy has been used to study transient processes in Ga _{.47}In_{.53 }As/InP multiple quantum wells (MQWs), and in bulk Ga_{.47}In _{.53}As and GaSb. To facilitate the experimental studies, apparatus was constructed to allow the detection of transient luminescence with 3ps time resolution. A frequency upconversion technique was employed. Relaxation of energetic carriers in bulk Ga _{.47}In_{.53 }As by optic phonons has been investigated, and, at carrier densities ~3 times 10^{18}cm ^{-3} is found to be a considerably slower process than simple theory predicts. The discrepancy is resolved by the inclusion of a non-equilibrium population of longitudinal optic phonons in the theoretical description. Slow energy loss is also observed in a 154A MQW under similar conditions, but carriers are found to relax more quickly in a 14A MQW with a comparable repeat period. The theory of non-equilibrium mode occupation is modified to describe the case of a MQW and is found to agree with experiment. Carrier relaxation in GaSb is studied and the importance of occupation of the L _6 conduction band valley in this material is demonstrated. The ambipolar diffusion of a photoexcited carrier plasma through an InP capping layer was investigated using an optical time-of-flight technique. This experiment also enables the efficiency of carrier capture by a Ga _{.47}In_{.53 }As quantum well to be determined. A capture time of 4ps was found.

Use of injectable promethazine to decrease symptom scores of Space Motion Sickness

NASA Technical Reports Server (NTRS)

Beck, B. G.; Nicogossian, A. E.

1992-01-01

Space motion sickness (SMS) has been a problem affecting approximately 74 percent of first time shuttle flyers. Promethazine injections have been used for 29 cases of SMS to decrease the severity of their illness. Although reported to be effective in reducing symptoms in 27 of the 29 cases, there has been no proof of its efficacy. Methods: Retrospective analysis of medical debriefs examining the symptom scores for nausea, vomiting, decreased appetite, and stomach awareness were performed. Each symptom is rated on a mild = 1, moderate = 2, severe = 3 system for each flight day. Crewmember scores for the first three flight days on an initial flight in which injectable promethazine had not been used were compared to scores in a later flight in which the promethazine was utilized. Scores were also compared in a similar group of crewmembers who did not use promethazine. Results: There was a decrease in median scores for all symptoms except nausea, however, it was significant (p = 0.14) only for the vomiting scores. This significant decrease was not seen in the control group. Conclusions: Injectable promethazine has been associated with a significant decrease in vomiting compared to earlier flights in which injectable promethazine was not used.

Analysis of low altitude atmospheric turbulence data measured in flight

NASA Technical Reports Server (NTRS)

Ganzer, V. M.; Joppa, R. G.; Vanderwees, G.

1977-01-01

All three components of turbulence were measured simultaneously in flight at each wing tip of a Beech D-18 aircraft. The flights were conducted at low altitude, 30.5 - 61.0 meters (100-200 ft.), over water in the presence of wind driven turbulence. Statistical properties of flight measured turbulence were compared with Gaussian and non-Gaussian turbulence models. Spatial characteristics of the turbulence were analyzed using the data from flight perpendicular and parallel to the wind. The probability density distributions of the vertical gusts show distinctly non-Gaussian characteristics. The distributions of the longitudinal and lateral gusts are generally Gaussian. The power spectra compare in the inertial subrange at some points better with the Dryden spectrum, while at other points the von Karman spectrum is a better approximation. In the low frequency range the data show peaks or dips in the power spectral density. The cross between vertical gusts in the direction of the mean wind were compared with a matched non-Gaussian model. The real component of the cross spectrum is in general close to the non-Gaussian model. The imaginary component, however, indicated a larger phase shift between these two gust components than was found in previous research.

Functional liver image guided hepatic therapy (FLIGHT) with hepatobiliary iminodiacetic acid (HIDA) scans.

PubMed

Long, David E; Tann, Mark; Huang, Ke Colin; Bartlett, Gregory; Galle, James O; Furukawa, Yukie; Maluccio, Mary; Cox, John A; Kong, Feng-Ming Spring; Ellsworth, Susannah G

2018-05-01

Hepatobiliary iminodiacetic acid (HIDA) scans provide global and regional assessments of liver function that can serve as a road map for functional avoidance in stereotactic body radiation therapy (SBRT) planning. Functional liver image guided hepatic therapy (FLIGHT), an innovative planning technique, is described and compared with standard planning using functional dose-volume histograms. Thresholds predicting for decompensation during follow up are evaluated. We studied 17 patients who underwent HIDA scans before SBRT. All SBRT cases were replanned using FLIGHT. The following dosimetric endpoints were compared for FLIGHT versus standard SBRT planning: functional residual capacity <15 Gy (FRC 15 HIDA), mean liver dose (MLD), equivalent uniform dose (EUD), and functional EUD (FEUD). Receiver operating characteristics curves were used to evaluate whether baseline HIDA values, standard cirrhosis scoring, and/or dosimetric data predicted clinical decompensation. Compared with standard planning, FLIGHT significantly improved FRC 15 HIDA (mean improvement: 5.3%) as well as MLD, EUD, and FEUD (P < .05). Considerable interindividual variations in the extent of benefit were noted. Decompensation during follow-up was associated with baseline global HIDA <2.915%/min/m 2 , FRC 15 HIDA <2.11%/min/m 2 , and MELD ≥11 (P < .05). FLIGHT with HIDA-based parameters may complement blood chemistry-based assessments of liver function and facilitate individualized, adaptive liver SBRT planning. Copyright © 2018. Published by Elsevier Inc.

Comparative analysis of operational forecasts versus actual weather conditions in airline flight planning: Summary report

NASA Technical Reports Server (NTRS)

Keitz, J. F.

1982-01-01

The impact of more timely and accurate weather data on airline flight planning with the emphasis on fuel savings is studied. This summary report discusses the results of each of the four major tasks of the study. Task 1 compared airline flight plans based on operational forecasts to plans based on the verifying analyses and found that average fuel savings of 1.2 to 2.5 percent are possible with improved forecasts. Task 2 consisted of similar comparisons but used a model developed for the FAA by SRI International that simulated the impact of ATc diversions on the flight plans. While parts of Task 2 confirm the Task I findings, inconsistency with other data and the known impact of ATC suggests that other Task 2 findings are the result of errors in the model. Task 3 compares segment weather data from operational flight plans with the weather actually observed by the aircraft and finds the average error could result in fuel burn penalties (or savings) of up to 3.6 percent for the average 8747 flight. In Task 4 an in-depth analysis of the weather forecast for the 33 days included in the study finds that significant errors exist on 15 days. Wind speeds in the area of maximum winds are underestimated by 20 to 50 kts., a finding confirmed in the other three tasks.

The effect of real and simulated time-zone shifts upon the circadian rhythms of body temperature, plasma 11-hydroxycorticosteroids, and renal excretion in human subjects

PubMed Central

Elliott, Ann L.; Mills, J. N.; Minors, D. S.; Waterhouse, J. M.

1972-01-01

1. Observations were made upon five subjects who flew through 4½-6 time zones, four of them returning later to their starting point, and upon twenty-three subjects experiencing simulated 6 or 8 hr time zones shifts in either direction in an isolation unit. 2. Measurements were made of plasma concentration of 11-hydroxycorticosteroids, of body temperature, and of urinary excretion of sodium, potassium and chloride. Their rhythm was defined, where possible, by fitting a sine curve of period 24 hr to each separate 24-hr stretch of data and computing the acrophase, or maximum predicted by the sine curve. 3. The adaptation of the plasma steroid rhythm was assessed by the presence of a sharp fall in concentration after the sample collected around 08.00 hr. The time course of adaptation varied widely between individuals; it was usually largely complete by the fourth day after westward, and rather later after eastward, flights. After time shift the pattern often corresponded neither to an adapted nor to an unadapted one, and in a subject followed for many months after a real flight a normal amplitude only appeared 2-3 months after flight. 4. Temperature rhythm adapted by a movement of the acrophase, without change in amplitude, although on some days no rhythm could be observed. This movement was always substantial even on the first day, and was usually nearly complete by the fifth. 5. High nocturnal excretion of electrolyte was often seen in the early days after time shift, more notably after simulated westward flights. Adaptation of urinary electrolyte rhythms usually proceeded as with temperature, but the movement of the acrophase was slower, more variable between individuals, more erratic, and sometimes reversed after partial adaptation. On a few days there were two maxima corresponding to those expected on real and on experimental time. 6. Sodium excretion was much less regular than that of potassium, but adapted more rapidly to time shift, so that the two often became completely dissociated. Chloride behaved much as sodium. 7. The time course of adaptation of the plasma steroid and urinary potassium rhythms were sufficiently similar to suggest a causal connexion. The time course of adaptation of the temperature rhythm did not coincide with that of any other component considered here. PMID:5016984

Correlation of HIFiRE-5 Flight Data with Computed Pressure and Heat Transfer (Postprint)

DTIC Science & Technology

2015-06-01

AFRL-RQ-WP-TP-2015-0149 CORRELATION OF HIFiRE-5 FLIGHT DATA WITH COMPUTED PRESSURE AND HEAT TRANSFER (POSTPRINT) Joseph S. Jewell...results with St was compared to flight heat transfer measurements, and transition locations were inferred. Finally, a computational heat conduction...HIFiRE-5 Flight Data With Computed Pressure and Heat Transfer Joseph S. Jewell,1 James H. Miller,2 and Roger L. Kimmel3 U.S. Air Force Research

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The e-Genius aircraft is pulled pulled out to the runway for the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The e-Genius pilots talk with a fellow team member prior to their takeoff for the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The Pipistrel-USA team look up at aircraft as they participate in the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The Embry-Riddle Aeronautical University, EcoEagle prepares to takeoff as an demonstration aircraft for the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The checkered flag is waved as the PhoEnix aircraft crosses the finish line of the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The Pipistrel-USA, Taurus G4 aircraft is seen as it participates in the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Comparative Flight Activities and Pathogen Load of Two Stocks of Honey Bees Reared in Gamma-Irradiated Combs

PubMed Central

de Guzman, Lilia I.; Frake, Amanda M.

2017-01-01

Gamma irradiation is known to inactivate various pathogens that negatively affect honey bee health. Bee pathogens, such as Deformed wing virus (DWV) and Nosema spp., have a deleterious impact on foraging activities and bee survival, and have been detected in combs. In this study, we assessed the effects of gamma irradiation on the flight activities, pathogen load, and survival of two honey bee stocks that were reared in irradiated and non-irradiated combs. Overall, bee genotype influenced the average number of daily flights, the total number of foraging flights, and total flight duration, in which the Russian honey bees outperformed the Italian honey bees. Exposing combs to gamma irradiation only affected the age at first flight, with worker bees that were reared in non-irradiated combs foraging prematurely compared to those reared in irradiated combs. Precocious foraging may be associated with the higher levels of DWV in bees reared in non-irradiated combs and also with the lower amount of pollen stores in colonies that used non-irradiated combs. These data suggest that gamma irradiation of combs can help minimize the negative impact of DWV in honey bees. Since colonies with irradiated combs stored more pollen than those with non-irradiated combs, crop pollination efficiency may be further improved when mite-resistant stocks are used, since they performed more flights and had longer flight durations. PMID:29186033

Oxygen Uptake Kinetics Is Slower in Swimming Than Arm Cranking and Cycling during Heavy Intensity

PubMed Central

Sousa, Ana; Borrani, Fabio; Rodríguez, Ferran A.; Millet, Grégoire P.

2017-01-01

Oxygen uptake (V·O2) kinetics has been reported to be influenced by the activity mode. However, only few studies have compared V·O2 kinetics between activities in the same subjects in which they were equally trained. Therefore, this study compared the V·O2 kinetics response to swimming, arm cranking, and cycling within the same group of subjects within the heavy exercise intensity domain. Ten trained male triathletes (age 23.2 ± 4.5 years; height 180.8 ± 8.3 cm; weight 72.3 ± 6.6 kg) completed an incremental test to exhaustion and a 6-min heavy constant-load test in the three exercise modes in random order. Gas exchange was measured by a breath-by-breath analyzer and the on-transient V·O2 kinetics was modeled using bi-exponential functions. V·O2peak was higher in cycling (65.6 ± 4.0 ml·kg−1·min−1) than in arm cranking or swimming (48.7 ± 8.0 and 53.0 ± 6.7 ml·kg−1·min−1; P < 0.01), but the V·O2 kinetics were slower in swimming (τ1 = 31.7 ± 6.2 s) than in arm cranking (19.3 ± 4.2 s; P = 0.001) and cycling (12.4 ± 3.7 s; P = 0.001). The amplitude of the primary component was lower in both arm cranking and swimming (21.9 ± 4.7 and 28.4 ± 5.1 ml·kg−1·min−1) compared with cycling (39.4 ± 4.1 ml·kg−1·min−1; P = 0.001). Although the gain of the primary component was higher in arm cranking compared with cycling (15.3 ± 4.2 and 10.7 ± 1.3 ml·min−1·W−1; P = 0.02), the slow component amplitude, in both absolute and relative terms, did not differ between exercise modes. The slower V·O2 kinetics during heavy-intensity swimming is exercise-mode dependent. Besides differences in muscle mass and greater type II muscle fibers recruitment, the horizontal position adopted and the involvement of trunk and lower-body stabilizing muscles could be additional mechanisms that explain the differences between exercise modalities. PMID:28919863

Comparing the Impact of Refractive and Non-Refractive Vision Loss on Functioning and Disability: The Salisbury Eye Evaluation

PubMed Central

Zebardast, Nazlee; Swenor, Bonnielin K.; van Landingham, Suzanne W.; Massof, Robert W.; Munoz, Beatriz; West, Sheila K.; Ramulu, Pradeep Y.

2015-01-01

Purpose To compare the effects of uncorrected refractive error (URE) and non-refractive visual impairment (VI) on performance and disability measures. Design Cross-sectional population-based study. Participants 2469 individuals with binocular presenting visual acuity (PVA) of 20/80 or better who participated in the first round of the Salisbury Eye Evaluation study. Methods URE was defined as binocular PVA of 20/30 or worse, improving to better than 20/30 with subjective refraction. VI was defined as post-refraction binocular best corrected visual acuity (BCVA) of 20/30 or worse. The visual acuity decrement attributable to VI was calculated as the difference between BCVA and 20/30 while that due to URE was taken as the difference between PVA and BCVA. Multivariable regression analyses were used to assess the disability impact of 1) vision status (VI, URE, or normal vision) using the group with normal vision as reference, and 2) a one-line decrement in acuity due to VI or URE. Main Outcome Measures Objective measures of visual function were obtained from timed performance of mobility and near vision tasks, self-reported driving cessation, and self-reported visual difficulty measured by the Activities of Daily Vision (ADV) scale. ADV responses were analyzed using Rasch analysis to determine visual ability. Results Compared to individuals with normal vision, subjects with VI (n=191) had significantly poorer objective and subjective visual functioning in all metrics examined (p<0.05) while subjects with URE (n=132) demonstrated slower walking speeds, slower near task performance, more frequent driving cessation and lower ADV scores (p<0.05), but did not demonstrate slower stair climbing or descent speed. For all functional metrics evaluated, the impact of VI was greater than the impact of URE. The impact of a one-line VA decrement due to VI was associated with greater deficits in mobility measures and driving cessation when compared to a one-line VA decrement due to URE. Conclusions VI is associated with greater disability than URE across a wide variety of functional measures, even in analyses adjusting for the severity of vision loss. Refractive and non-refractive vision loss should be distinguished in studies evaluating visual disability, and should be understood to have differing consequences. PMID:25813453

Comparing the Impact of Refractive and Nonrefractive Vision Loss on Functioning and Disability: The Salisbury Eye Evaluation.

PubMed

Zebardast, Nazlee; Swenor, Bonnielin K; van Landingham, Suzanne W; Massof, Robert W; Munoz, Beatriz; West, Sheila K; Ramulu, Pradeep Y

2015-06-01

To compare the effects of uncorrected refractive error (URE) and nonrefractive visual impairment (VI) on performance and disability measures. Cross-sectional, population-based study. A total of 2469 individuals with binocular presenting visual acuity (PVA) of ≥ 20/80 who participated in the first round of the Salisbury Eye Evaluation study. The URE was defined as binocular PVA of ≤ 20/30, improving to >20/30 with subjective refraction. The VI was defined as post-refraction binocular best-corrected visual acuity (BCVA) of ≤ 20/30. The visual acuity decrement due to VI was calculated as the difference between BCVA and 20/30, whereas visual acuity due to URE was taken as the difference between PVA and BCVA. Multivariable regression analyses were used to assess the disability impact of (1) vision status (VI, URE, or normal vision) using the group with normal vision as reference and (2) a 1-line decrement in acuity due to VI or URE. Objective measures of visual function were obtained from timed performance of mobility and near vision tasks, self-reported driving cessation, and self-reported visual difficulty measured by the Activities of Daily Vision (ADV) scale. The ADV responses were analyzed using Rasch analysis to determine visual ability. Compared with individuals with normal vision, subjects with VI (n = 191) had significantly poorer objective and subjective visual functioning in all metrics examined (P < 0.05), whereas subjects with URE (n = 132) demonstrated slower walking speeds, slower near task performance, more frequent driving cessation, and lower ADV scores (P < 0.05), but did not demonstrate slower stair climbing or descent speed. For all functional metrics evaluated, the impact of VI was greater than the impact of URE. The impact of a 1-line VA decrement due to VI was associated with greater deficits in mobility measures and driving cessation when compared with a 1-line VA decrement due to URE. Visual impairment is associated with greater disability than URE across a wide variety of functional measures, even in analyses adjusting for the severity of vision loss. Refractive and nonrefractive vision loss should be distinguished in studies evaluating visual disability and be understood to have differing consequences. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Retinal Adaptation Abnormalities in Primary Open-Angle Glaucoma

PubMed Central

Dul, Mitchell; Ennis, Robert; Radner, Shira; Lee, Barry; Zaidi, Qasim

2015-01-01

Purpose. Dynamic color and brightness adaptation are crucial for visual functioning. The effects of glaucoma on retinal ganglion cells (RGCs) could compromise these functions. We have previously used slow dynamic changes of light at moderate intensities to measure the speed and magnitude of subtractive adaptation in RGCs. We used the same procedure to test if RGC abnormalities cause slower and weaker adaptation for patients with glaucoma when compared to age-similar controls. We assessed adaptation deficits in specific classes of RGCs by testing along the three cardinal color axes that isolate konio, parvo, and magno RGCs. Methods. For one eye each of 10 primary open-angle glaucoma patients and their age-similar controls, we measured the speed and magnitude of adapting to 1/32 Hz color modulations along the three cardinal axes, at central fixation and 8° superior, inferior, nasal, and temporal to fixation. Results. In all 15 comparisons (5 locations × 3 color axes), average adaptation was slower and weaker for glaucoma patients than for controls. Adaptation developed slower at central targets than at 8° eccentricities for controls, but not for patients. Adaptation speed and magnitude differed between affected and control eyes even at retinal locations showing no visual field loss with clinical perimetry. Conclusions. Neural adaptation is weaker in glaucoma patients for all three classes of RGCs. Since adaptation abnormalities are manifested even at retinal locations not exhibiting a visual field loss, this novel form of assessment may offer a functional insight into glaucoma and an early diagnosis tool. PMID:25613950

Flapping wing flight can save aerodynamic power compared to steady flight.

PubMed

Pesavento, Umberto; Wang, Z Jane

2009-09-11

Flapping flight is more maneuverable than steady flight. It is debated whether this advantage is necessarily accompanied by a trade-off in the flight efficiency. Here we ask if any flapping motion exists that is aerodynamically more efficient than the optimal steady motion. We solve the Navier-Stokes equation governing the fluid dynamics around a 2D flapping wing, and determine the minimal aerodynamic power needed to support a specified weight. While most flapping wing motions are more costly than the optimal steady wing motion, we find that optimized flapping wing motions can save up to 27% of the aerodynamic power required by the optimal steady flight. We explain the cause of this energetic advantage.

Propulsion system-flight control integration-flight evaluation and technology transition

NASA Technical Reports Server (NTRS)

Burcham, Frank W., Jr.; Gilyard, Glenn B.; Myers, Lawrence P.

1990-01-01

Integration of propulsion and flight control systems and their optimization offering significant performance improvement are assessed. In particular, research programs conducted by NASA on flight control systems and propulsion system-flight control interactions on the YF-12 and F-15 aircraft are addressed; these programs have demonstrated increased thrust, reduced fuel consumption, increased engine life, and improved aircraft performance. Focus is placed on altitude control, speed-Mach control, integrated controller design, as well as flight control systems and digital electronic engine control. A highly integrated digital electronic control program is analyzed and compared with a performance seeking control program. It is shown that the flight evaluation and demonstration of these technologies have been a key part in the transition of the concepts to production and operational use on a timely basis.

Post-Flight Aerodynamic and Aerothermal Model Validation of a Supersonic Inflatable Aerodynamic Decelerator

NASA Technical Reports Server (NTRS)

Tang, Chun; Muppidi, Suman; Bose, Deepak; Van Norman, John W.; Tanimoto, Rebekah; Clark, Ian

2015-01-01

NASA's Low Density Supersonic Decelerator Program is developing new technologies that will enable the landing of heavier payloads in low density environments, such as Mars. A recent flight experiment conducted high above the Hawaiian Islands has demonstrated the performance of several decelerator technologies. In particular, the deployment of the Robotic class Supersonic Inflatable Aerodynamic Decelerator (SIAD-R) was highly successful, and valuable data were collected during the test flight. This paper outlines the Computational Fluid Dynamics (CFD) analysis used to estimate the aerodynamic and aerothermal characteristics of the SIAD-R. Pre-flight and post-flight predictions are compared with the flight data, and a very good agreement in aerodynamic force and moment coefficients is observed between the CFD solutions and the reconstructed flight data.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Towprayoon, S.; Kuntrangwattana, S.

Cutting oil wastewater from an iron and steel factory was applied to the soil windrow. Self-remediation was then compared with remediation with acclimatized indigenous microbes. The incremental reduction rate of the microorganisms and hydrocarbon-degradable microbes was slower in self-remediation than in the latter treatment. Within 30 days, when the acclimatized indigenous microbes were used, there was a significant reduction of the contaminated hydrocarbons, while self-remediation took longer to reduce to the same concentration. Various nitrogen sources were applied to the soil pile, namely, organic compost, chemical fertilizer, ammonium sulfate, and urea. The organic compost induced a high yield of hydrocarbon-degradablemore » microorganisms, but the rate at which the cutting oil in the soil decreased was slower than when other nitrogen sources were used. The results of cutting oil degradation studied by gas chromatography showed the absence of some important hydrocarbons. The increment of the hydrocarbon-degradable microbes in the land treatment ecosystem does not necessarily correspond to the hydrocarbon reduction efficiency. 3 refs., 3 figs.« less

The impact of finger counting habits on arithmetic in adults and children.

PubMed

Newman, Sharlene D; Soylu, Firat

2014-07-01

Here, we explored the impact of finger counting habits on arithmetic in both adults and children. Two groups of participants were examined, those that begin counting with their left hand (left-starters) and those that begin counting with their right hand (right-starters). For the adults, performance on an addition task in which participants added 2 two-digit numbers was compared. The results revealed that left-starters were slower than right-starters when adding and they had lower forward and backward digit-span scores. The children (aged 5-12) showed similar results on a single-digit timed addition task-right-starters outperformed left-starters. However, the children did not reveal differences in working memory or verbal and non-verbal intelligence as a function of finger counting habit. We argue that the motor act of finger counting influences how number is represented and suggest that left-starters may have a more bilateral representation that accounts for the slower processing.

A comparative analysis of carbon dioxide displacement rates for euthanasia of the ferret.

PubMed

Fitzhugh, Dawn C; Parmer, Amanda; Shelton, Larry J; Sheets, James T

2008-02-01

Though carbon dioxide asphyxiation is a common method of euthanasia for laboratory animals, species-specific guidelines have not been established for this procedure in the domestic ferret (Mustela putorius furo). The authors investigated the efficacy and stress effects of carbon dioxide euthanasia in 24 ferrets that had participated in previous experimental protocols. They euthanized ferrets by placing them in cages that were either prefilled with carbon dioxide or gradually filled at a displacement rate of 10%, 20% or 50% of the cage volume per min. Blinded observers subjectively evaluated ferret distress. Prefilling the cage or filling it at a rate of 50% volume per min resulted in less time to recumbency and to last breath than did filling the cage at a slower displacement rate. Slower carbon dioxide displacement rates also caused an increase in ferret blood glucose concentrations, which may indicate distress. Overall, observers found that prefilling the euthanasia cage caused the least stress to ferrets.

Balance Training Reduces Falls Risk in Older Individuals With Type 2 Diabetes

PubMed Central

Morrison, Steven; Colberg, Sheri R.; Mariano, Mira; Parson, Henri K.; Vinik, Arthur I.

2010-01-01

OBJECTIVE This study assessed the effects of balance/strength training on falls risk and posture in older individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS Sixteen individuals with type 2 diabetes and 21 age-matched control subjects (aged 50–75 years) participated. Postural stability and falls risk was assessed before and after a 6-week exercise program. RESULTS Diabetic individuals had significantly higher falls risk score compared with control subjects. The diabetic group also exhibited evidence of mild-to-moderate neuropathy, slower reaction times, and increased postural sway. Following exercise, the diabetic group showed significant improvements in leg strength, faster reaction times, decreased sway, and, consequently, reduced falls risk. CONCLUSIONS Older individuals with diabetes had impaired balance, slower reactions, and consequently a higher falls risk than age-matched control subjects. However, all these variables improved after resistance/balance training. Together these results demonstrate that structured exercise has wide-spread positive effects on physiological function for older individuals with type 2 diabetes. PMID:20097781

"Paradox of slow frequencies" - Are slow frequencies in upper cortical layers a neural predisposition of the level/state of consciousness (NPC)?

PubMed

Northoff, Georg

2017-09-01

Consciousness research has much focused on faster frequencies like alpha or gamma while neglecting the slower ones in the infraslow (0.001-0.1Hz) and slow (0.1-1Hz) frequency range. These slower frequency ranges have a "bad reputation" though; their increase in power can observed during the loss of consciousness as in sleep, anesthesia, and vegetative state. However, at the same time, slower frequencies have been conceived instrumental for consciousness. The present paper aims to resolve this paradox which I describe as "paradox of slow frequencies". I first show various data that suggest a central role of slower frequencies in integrating faster ones, i.e., "temporo-spatial integration and nestedness". Such "temporo-spatial integration and nestedness" is disrupted during the loss of consciousness as in anesthesia and sleep leading to "temporo-spatial fragmentation and isolation" between slow and fast frequencies. Slow frequencies are supposedly mediated by neural activity in upper cortical layers in higher-order associative regions as distinguished from lower cortical layers that are related to faster frequencies. Taken together, slower and faster frequencies take on different roles for the level/state of consciousness. Faster frequencies by themselves are sufficient and thus a neural correlate of consciousness (NCC) while slower frequencies are a necessary non-sufficient condition of possible consciousness, e.g., a neural predisposition of the level/state of consciousness (NPC). This resolves the "paradox of slow frequencies" in that it assigns different roles to slower and faster frequencies in consciousness, i.e., NCC and NPC. Taken as NCC and NPC, fast and slow frequencies including their relation as in "temporo-spatial integration and nestedness" can be considered a first "building bloc" of a future "temporo-spatial theory of consciousness" (TTC) (Northoff, 2013; Northoff, 2014b; Northoff & Huang, 2017). Copyright © 2017 Elsevier Inc. All rights reserved.

Correlating Computed and Flight Instructor Assessments of Straight-In Landing Approaches by Novice Pilots on a Flight Simulator

NASA Technical Reports Server (NTRS)

Heath, Bruce E.; Khan, M. Javed; Rossi, Marcia; Ali, Syed Firasat

2005-01-01

The rising cost of flight training and the low cost of powerful computers have resulted in increasing use of PC-based flight simulators. This has prompted FAA standards regulating such use and allowing aspects of training on simulators meeting these standards to be substituted for flight time. However, the FAA regulations require an authorized flight instructor as part of the training environment. Thus, while costs associated with flight time have been reduced, the cost associated with the need for a flight instructor still remains. The obvious area of research, therefore, has been to develop intelligent simulators. However, the two main challenges of such attempts have been training strategies and assessment. The research reported in this paper was conducted to evaluate various performance metrics of a straight-in landing approach by 33 novice pilots flying a light single engine aircraft simulation. These metrics were compared to assessments of these flights by two flight instructors to establish a correlation between the two techniques in an attempt to determine a composite performance metric for this flight maneuver.

Methodology for Flight Relevant Arc-Jet Testing of Flexible Thermal Protection Systems

NASA Technical Reports Server (NTRS)

Mazaheri, Alireza; Bruce, Walter E., III; Mesick, Nathaniel J.; Sutton, Kenneth

2013-01-01

A methodology to correlate flight aeroheating environments to the arc-jet environment is presented. For a desired hot-wall flight heating rate, the methodology provides the arcjet bulk enthalpy for the corresponding cold-wall heating rate. A series of analyses were conducted to examine the effects of the test sample model holder geometry to the overall performance of the test sample. The analyses were compared with arc-jet test samples and challenges and issues are presented. The transient flight environment was calculated for the Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Earth Atmospheric Reentry Test (HEART) vehicle, which is a planned demonstration vehicle using a large inflatable, flexible thermal protection system to reenter the Earth's atmosphere from the International Space Station. A series of correlations were developed to define the relevant arc-jet test environment to properly approximate the HEART flight environment. The computed arcjet environments were compared with the measured arc-jet values to define the uncertainty of the correlated environment. The results show that for a given flight surface heat flux and a fully-catalytic TPS, the flight relevant arc-jet heat flux increases with the arc-jet bulk enthalpy while for a non-catalytic TPS the arc-jet heat flux decreases with the bulk enthalpy.

Orthostatic intolerance and motion sickness after parabolic flight

NASA Technical Reports Server (NTRS)

Schlegel, T. T.; Brown, T. E.; Wood, S. J.; Benavides, E. W.; Bondar, R. L.; Stein, F.; Moradshahi, P.; Harm, D. L.; Fritsch-Yelle, J. M.; Low, P. A.

2001-01-01

Because it is not clear that the induction of orthostatic intolerance in returning astronauts always requires prolonged exposure to microgravity, we investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy subjects before and after the brief micro- and hypergravity of parabolic flight. Concomitantly, we investigated the effect of parabolic flight-induced vomiting on orthostatic tolerance, R-wave-R-wave interval and arterial pressure power spectra, and carotid-cardiac baroreflex and Valsalva responses. After parabolic flight 1) 8 of 16 subjects could not tolerate 30 min of upright tilt (compared to 2 of 16 before flight); 2) 6 of 16 subjects vomited; 3) new intolerance to upright tilt was associated with exaggerated falls in total peripheral resistance, whereas vomiting was associated with increased R-wave-R-wave interval variability and carotid-cardiac baroreflex responsiveness; and 4) the proximate mode of new orthostatic failure differed in subjects who did and did not vomit, with vomiters experiencing comparatively isolated upright hypocapnia and cerebral vasoconstriction and nonvomiters experiencing signs and symptoms reminiscent of the clinical postural tachycardia syndrome. Results suggest, first, that syndromes of orthostatic intolerance resembling those developing after space flight can develop after a brief (i.e., 2-h) parabolic flight and, second, that recent vomiting can influence the results of tests of autonomic cardiovascular function commonly utilized in returning astronauts.

Predictive adaptive responses: Condition-dependent impact of adult nutrition and flight in the tropical butterfly Bicyclus anynana.

PubMed

Saastamoinen, Marjo; van der Sterren, Dominique; Vastenhout, Nienke; Zwaan, Bas J; Brakefield, Paul M

2010-12-01

The experience of environmental stress during development can substantially affect an organism's life history. These effects are often mainly negative, but a growing number of studies suggest that under certain environmental conditions early experience of such stress may yield individuals that are less sensitive to environmental stress later on in life. We used the butterfly Bicyclus anynana to study the effects of limited larval and adult food and forced flight on individual performance measured as reproduction and adult life span. Larvae exposed to food stress showed longer development and produced smaller adults. Thus, they were not able to fully compensate for the food deprivation during development. Females that experienced food stress during development did not increase tolerance for adult food limitation. However, females exposed to food stress during development coped better with forced flight compared with the control group. The apparent absence of costs of flight in poor-quality females may be a by-product of an altered body allocation, as females experiencing both food stress treatments had increased thorax ratios, compared with controls, and increased flight performances. The results reveal an important plasticity component to variation in flight performance and suggest that the cost of flight depends on an individual's internal condition.

Results of a simulator test comparing two display concepts for piloted flight-path-angle control

NASA Technical Reports Server (NTRS)

Kelley, W. W.

1978-01-01

Results of a simulator experiment which was conducted in order to compare pilot gamma-control performance using two display formats are reported. Pilots flew a variable flight path angle tracking task in the landing configuration. Pilot and airplane performance parameters were recorded and pilot comments noted for each case.

Carcass and meat quality of dual-purpose chickens (Lohmann Dual, Belgian Malines, Schweizerhuhn) in comparison to broiler and layer chicken types.

PubMed

Mueller, S; Kreuzer, M; Siegrist, M; Mannale, K; Messikommer, R E; Gangnat, I D M

2018-05-18

Currently, there is an intensive ethical discussion about the practice of culling day-old layer cockerels. One solution to avoid this practice could be using dual-purpose types, where males are fattened for meat and females used for egg production. The aim of the present study was to compare fattening performance, carcass conformation, and composition as well as meat quality of Lohmann Dual, a novel dual-purpose type, and 2 traditional dual-purpose types (Belgian Malines and Schweizerhuhn) with 2 broiler types and 1 layer type (Lohmann Brown Plus). Broilers included a conventional line (Ross PM3) and a slower-growing line (Sasso 51) fulfilling requirements of organic farming. Nine birds of each type were fed on a conventional broiler diet. Feed intake and metabolizability of nitrogen and energy were recorded per pen (n = 3), the latter through excreta sampling. For each bird, carcass conformation was assessed, and weights of body, carcass, breast meat, legs, wings, and inner organs were determined. Additionally, breast angle, an indicator for carcass appeal, and skin color were recorded. Meat quality assessment included determinations of thaw and cooking loss, shear force, meat color, and proximate composition of the breast meat. None of the dual-purpose types (20 to 30 g ADG) performed as well in growth as the intensively growing broiler line (68 g ADG). However, Lohmann Dual could compete with the slower-growing broiler line (slower growth but better feed efficiency, similar in carcass weight and breast proportion). Also breast angle was quite similar between Lohmann Dual (100°) and the extensive broiler type (115°C) compared to the intensive broiler line (180°). Meat quality was most favorable in the intensive broilers with the smallest shear force and thawing loss, whereas meat quality was not different between the other types. The Schweizerhuhn performed only at the level of the layer hybrid, and the Belgian Malines was ranked only slightly better.

Coping with Self-Threat and the Evaluation of Self-Related Traits: An fMRI Study

PubMed Central

Corcoran, Katja; Ebner, Franz

2015-01-01

A positive view of oneself is important for a healthy lifestyle. Self-protection mechanisms such as suppressing negative self-related information help us to maintain a positive view of ourselves. This is of special relevance when, for instance, a negative test result threatens our positive self-view. To date, it is not clear which brain areas support self-protective mechanisms under self-threat. In the present functional magnetic resonance imaging (fMRI) study the participants (N = 46) received a (negative vs. positive) performance test feedback before entering the scanner. In the scanner, the participants were instructed to ascribe personality traits either to themselves or to a famous other. Our results showed that participants responded slower to negative self-related traits compared to positive self-related traits. High self-esteem individuals responded slower to negative traits compared to low self-esteem individuals following a self-threat. This indicates that high self-esteem individuals engage more in self-enhancing strategies after a threat by inhibiting negative self-related information more successfully than low self-esteem individuals. This behavioral pattern was mirrored in the fMRI data as dACC correlated positively with trait self-esteem. Generally, ACC activation was attenuated under threat when participants evaluated self-relevant traits and even more for negative self-related traits. We also found that activation in the ACC was negatively correlated with response times, indicating that greater activation of the ACC is linked to better access (faster response) to positive self-related traits and to impaired access (slower response) to negative self-related traits. These results confirm the ACC function as important in managing threatened self-worth but indicate differences in trait self-esteem levels. The fMRI analyses also revealed a decrease in activation within the left Hippocampus and the right thalamus under threat. This indicates that a down-regulation of activation in these regions might also serve as coping mechanism in dealing with self-threat. PMID:26333130

Macroscopic kinetics of pentameric ligand gated ion channels: comparisons between two prokaryotic channels and one eukaryotic channel.

PubMed

Laha, Kurt T; Ghosh, Borna; Czajkowski, Cynthia

2013-01-01

Electrochemical signaling in the brain depends on pentameric ligand-gated ion channels (pLGICs). Recently, crystal structures of prokaryotic pLGIC homologues from Erwinia chrysanthemi (ELIC) and Gloeobacter violaceus (GLIC) in presumed closed and open channel states have been solved, which provide insight into the structural mechanisms underlying channel activation. Although structural studies involving both ELIC and GLIC have become numerous, thorough functional characterizations of these channels are still needed to establish a reliable foundation for comparing kinetic properties. Here, we examined the kinetics of ELIC and GLIC current activation, desensitization, and deactivation and compared them to the GABAA receptor, a prototypic eukaryotic pLGIC. Outside-out patch-clamp recordings were performed with HEK-293T cells expressing ELIC, GLIC, or α1β2γ2L GABAA receptors, and ultra-fast ligand application was used. In response to saturating agonist concentrations, we found both ELIC and GLIC current activation were two to three orders of magnitude slower than GABAA receptor current activation. The prokaryotic channels also had slower current desensitization on a timescale of seconds. ELIC and GLIC current deactivation following 25 s pulses of agonist (cysteamine and pH 4.0 buffer, respectively) were relatively fast with time constants of 24.9 ± 5.1 ms and 1.2 ± 0.2 ms, respectively. Surprisingly, ELIC currents evoked by GABA activated very slowly with a time constant of 1.3 ± 0.3 s and deactivated even slower with a time constant of 4.6 ± 1.2 s. We conclude that the prokaryotic pLGICs undergo similar agonist-mediated gating transitions to open and desensitized states as eukaryotic pLGICs, supporting their use as experimental models. Their uncharacteristic slow activation, slow desensitization and rapid deactivation time courses are likely due to differences in specific structural elements, whose future identification may help uncover mechanisms underlying pLGIC gating transitions.

Robotic gaming prototype for upper limb exercise: Effects of age and embodiment on user preferences and movement.

PubMed

Eizicovits, Danny; Edan, Yael; Tabak, Iris; Levy-Tzedek, Shelly

2018-01-01

Effective human-robot interactions in rehabilitation necessitates an understanding of how these should be tailored to the needs of the human. We report on a robotic system developed as a partner on a 3-D everyday task, using a gamified approach. To: (1) design and test a prototype system, to be ultimately used for upper-limb rehabilitation; (2) evaluate how age affects the response to such a robotic system; and (3) identify whether the robot's physical embodiment is an important aspect in motivating users to complete a set of repetitive tasks. 62 healthy participants, young (<30 yo) and old (>60 yo), played a 3D tic-tac-toe game against an embodied (a robotic arm) and a non-embodied (a computer-controlled lighting system) partner. To win, participants had to place three cups in sequence on a physical 3D grid. Cup picking-and-placing was chosen as a functional task that is often practiced in post-stroke rehabilitation. Movement of the participants was recorded using a Kinect camera. The timing of the participants' movement was primed by the response time of the system: participants moved slower when playing with the slower embodied system (p = 0.006). The majority of participants preferred the robot over the computer-controlled system. Slower response time of the robot compared to the computer-controlled one only affected the young group's motivation to continue playing. We demonstrated the feasibility of the system to encourage the performance of repetitive 3D functional movements, and track these movements. Young and old participants preferred to interact with the robot, compared with the non-embodied system. We contribute to the growing knowledge concerning personalized human-robot interactions by (1) demonstrating the priming of the human movement by the robotic movement - an important design feature, and (2) identifying response-speed as a design variable, the importance of which depends on the age of the user.

Effect of voluntary hyperventilation with supplemental CO2 on pulmonary O2 uptake and leg blood flow kinetics during moderate-intensity exercise.

PubMed

Chin, Lisa M K; Heigenhauser, George J F; Paterson, Donald H; Kowalchuk, John M

2013-12-01

Pulmonary O2 uptake (V(O₂p)) and leg blood flow (LBF) kinetics were examined at the onset of moderate-intensity exercise, during hyperventilation with and without associated hypocapnic alkalosis. Seven male subjects (25 ± 6 years old; mean ± SD) performed alternate-leg knee-extension exercise from baseline to moderate-intensity exercise (80% of estimated lactate threshold) and completed four to six repetitions for each of the following three conditions: (i) control [CON; end-tidal partial pressure of CO2 (P(ET, CO₂)) ~40 mmHg], i.e. normal breathing with normal inspired CO2 (0.03%); (ii) hypocapnia (HYPO; P(ET, CO₂) ~20 mmHg), i.e. sustained hyperventilation with normal inspired CO2 (0.03%); and (iii) normocapnia (NORMO; P(ET, CO₂) ~40 mmHg), i.e. sustained hyperventilation with elevated inspired CO2 (~5%). The V(O₂p) was measured breath by breath using mass spectrometry and a volume turbine. Femoral artery mean blood velocity was measured by Doppler ultrasound, and LBF was calculated from femoral artery diameter and mean blood velocity. Phase 2 V(O₂p) kinetics (τV(O₂p)) was different (P < 0.05) amongst all three conditions (CON, 19 ± 7 s; HYPO, 43 ± 17 s; and NORMO, 30 ± 8 s), while LBF kinetics (τLBF) was slower (P < 0.05) in HYPO (31 ± 9 s) compared with both CON (19 ± 3 s) and NORMO (20 ± 6 s). Similar to previous findings, HYPO was associated with slower V(O₂p) and LBF kinetics compared with CON. In the present study, preventing the fall in end-tidal P(CO₂) (NORMO) restored LBF kinetics, but not V(O₂p) kinetics, which remained 'slowed' relative to CON. These data suggest that the hyperventilation manoeuvre itself (i.e. independent of induced hypocapnic alkalosis) may contribute to the slower V(O₂p) kinetics observed during HYPO.

Zone-forming fungi experiment MA-147

NASA Technical Reports Server (NTRS)

Rogers, T. D.; Taylor, G. R.; Brower, M. E.

1976-01-01

Streptomyces levoris was used as an experimental microorganism during the Apollo Soyuz Test Project to study specific biological considerations that may be influenced by space flight factors. Preflight, inflight, and postflight growth rates of the cultures were compared by photographing the specimens at regular intervals. Preliminary results based on visual comparison of the photographic data indicate that an increased growth rate occurred during space flight in two of eight flight specimens. The increased growth rate continued in the two specimens during the postflight period until termination of the experiment. Radiation effects may be responsible for the absence of spores in two areas of the last spore ring that was formed during the inflight period in one of the flight cultures; however, the radiation studies related to this experiment have not been completed. Distinct morphological differences in spore rings were observed when postflight spore rings were compared with inflight spore rings. Factors that are related to space flight recovery and reentry into earth gravity may have effected these alterations.

Helicopter force-feel and stability augmentation system with parallel servo-actuator

NASA Technical Reports Server (NTRS)

Hoh, Roger H. (Inventor)

2006-01-01

A force-feel system is implemented by mechanically coupling a servo-actuator to and in parallel with a flight control system. The servo-actuator consists of an electric motor, a gearing device, and a clutch. A commanded cockpit-flight-controller position is achieved by pilot actuation of a trim-switch. The position of the cockpit-flight-controller is compared with the commanded position to form a first error which is processed by a shaping function to correlate the first error with a commanded force at the cockpit-flight-controller. The commanded force on the cockpit-flight-controller provides centering forces and improved control feel for the pilot. In an embodiment, the force-feel system is used as the basic element of stability augmentation system (SAS). The SAS provides a stabilization signal that is compared with the commanded position to form a second error signal. The first error is summed with the second error for processing by the shaping function.

Morphogenesis in bat wings: linking development, evolution and ecology.

PubMed

Adams, Rick A

2008-01-01

The evolution of powered flight in mammals required specific developmental shifts from an ancestral limb morphology to one adapted for flight. Through studies of comparative morphogenesis, investigators have quantified points and rates of divergence providing important insights into how wings evolved in mammals. Herein I compare growth,development and skeletogenesis of forelimbs between bats and the more ancestral state provided by the rat (Rattus norvegicus)and quantify growth trajectories that illustrate morphological divergence both developmentally and evolutionarily. In addition, I discuss how wing shape is controlled during morphogenesis by applying multivariate analyses of wing bones and wing membranes and discuss how flight dynamics are stabilized during flight ontogeny. Further, I discuss the development of flight in bats in relation to the ontogenetic niche and how juveniles effect populational foraging patterns. In addition, I provide a hypothetical ontogenetic landscape model that predicts how and when selection is most intense during juvenile morphogenesis and test this model with data from a population of the little brown bat, Myotis lucifugus. (c) 2007 S. Karger AG, Basel

A parachute system for upper atmospheric studies

NASA Technical Reports Server (NTRS)

Maksimovic, V. M.

1979-01-01

The Goddard Space Flight Center's Sounding Rocket Division successfully flight tested a high altitude, low velocity, 63.5 foot cross parachute system. The system was developed to provide a platform for atmospheric studies at altitudes higher than those attainable with balloons. This paper represents the approach taken to determine the necessary conditions for a successful apogee deployment of the parachute. The test flight deployed the parachute system at an apogee altitude of 61 kilometers. Post-flight results of rocket and parachute performance are compared to the preflight analyses.

Calculation of Shuttle Base Heating Environments and Comparison with Flight Data

NASA Technical Reports Server (NTRS)

Greenwood, T. F.; Lee, Y. C.; Bender, R. L.; Carter, R. E.

1983-01-01

The techniques, analytical tools, and experimental programs used initially to generate and later to improve and validate the Shuttle base heating design environments are discussed. In general, the measured base heating environments for STS-1 through STS-5 were in good agreement with the preflight predictions. However, some changes were made in the methodology after reviewing the flight data. The flight data is described, preflight predictions are compared with the flight data, and improvements in the prediction methodology based on the data are discussed.

Green Flight Challenge

NASA Image and Video Library

2011-09-27

CAFE Foundation Hanger Boss Mike Fenn waves the checkered flag as aircraft pass the finish line of the miles per gallon (MPG) flight during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Lateral stability and control derivatives extracted from space shuttle Challenger flight data

NASA Technical Reports Server (NTRS)

Schiess, James R.

1988-01-01

Flight data taken from six flights of the Space Transportation System shuttle Challenger (STS-6, 7, 8, 11, 13 and 17) during atmospheric entry are analyzed to determine the shuttle lateral aerodynamic characteristics. Maximum likelihood estimation is applied to data derived from accelerometer and rate gyro measurements and trajectory, meteorological and control surface data to estimate lateral-directional stability and control derivatives. The vehicle stability and control surface effectiveness are compared across the flights and to preflight predicted values.

Lateral stability and control derivatives extracted from five early flights of the space shuttle Columbia

NASA Technical Reports Server (NTRS)

Schiess, J. R.

1986-01-01

Flight data taken from the first five flights (STS-2, 3, 4, 5 and 9) of the Space Transportation System Shuttle Columbia during entry are analyzed to determine the Shuttle lateral aerodynamic characteristics. Maximum likelihood estimation is applied to data derived from accelerometer and rate gyro measurements and trajectory, meteorological and control surface data to estimate lateral-directional stability and control derivatives. The estimated parameters are compared across the five flights and to preflight predicted values.

Selected Flight Test Results for Online Learning Neural Network-Based Flight Control System

NASA Technical Reports Server (NTRS)

Williams-Hayes, Peggy S.

2004-01-01

The NASA F-15 Intelligent Flight Control System project team developed a series of flight control concepts designed to demonstrate neural network-based adaptive controller benefits, with the objective to develop and flight-test control systems using neural network technology to optimize aircraft performance under nominal conditions and stabilize the aircraft under failure conditions. This report presents flight-test results for an adaptive controller using stability and control derivative values from an online learning neural network. A dynamic cell structure neural network is used in conjunction with a real-time parameter identification algorithm to estimate aerodynamic stability and control derivative increments to baseline aerodynamic derivatives in flight. This open-loop flight test set was performed in preparation for a future phase in which the learning neural network and parameter identification algorithm output would provide the flight controller with aerodynamic stability and control derivative updates in near real time. Two flight maneuvers are analyzed - pitch frequency sweep and automated flight-test maneuver designed to optimally excite the parameter identification algorithm in all axes. Frequency responses generated from flight data are compared to those obtained from nonlinear simulation runs. Flight data examination shows that addition of flight-identified aerodynamic derivative increments into the simulation improved aircraft pitch handling qualities.

Respiratory symptoms of flight attendants during high-altitude flight: possible relation to cabin ozone exposure.

PubMed

Tashkin, D P; Coulson, A H; Simmons, M S; Spivey, G H

1983-01-01

The smaller size and lighter weight of the Boeing 747SP aircraft, introduced into passenger service in 1976, permitted higher-altitude flight than older commercial aircraft and thus potentially greater ozone exposure for those of board. Concerned flight attendants distributed questionnaires relating to symptoms experienced on the Boeing 747SP and/or conventional 747 aircraft to Los Angeles- and New York-based flight attendants. Respondents reported symptoms by frequency and severity and by in-flight and after-flight occurrence. Based on the assessment of three health scientists as to ozone-relatedness, the frequency of "definite" and "probable" ozone-related symptoms of any severity reported by both groups of attendants was significantly associated with 747SP flights (chi-squares: P less than 0.05). After-flight symptoms significantly associated with 747SP experience, although fewer in number than in-flight symptoms, were all in the scientists' "definite" category. In 21 flight attendants who complained of moderate to severe symptoms during 747SP flights, a battery of pulmonary function tests performed approximately two weeks after their last 747SP flight failed to reveal abnormalities. The symptom questionnaire results are consistent with possible exposure of cabin attendants to toxic levels of ozone during the higher-altitude flights of the Boeing 747SP compared to conventional 747 aircraft.

High Prevalence and Clinical/Sociodemographic Correlates of Miscarriages Among Flight Attendants.

PubMed

Heidecker, Bettina; Spencer, Rachel Maureen; Hayes, Victoria; Hall, Sarah; Parikh, Nisha; Stock, Eveline Oestreicher; Redberg, Rita

2017-12-01

There are many occupational health hazards associated with long hours of air travel, including cosmic radiation exposure, circadian rhythm disruptions, prior and secondhand smoke exposure, for flight attendants who flew before smoking bans were initiated in the 1990s. Previous studies in flight attendants have found increased incidence of breast cancer and melanoma. However, there is little information on the relationship of airline travel and reproductive health in flight attendants. Secondhand smoke exposure has numerous negative health effects, such as increased cardiac events and respiratory infections, but its effect on reproductive health is not known. This study seeks to examine the role of secondhand smoke exposure on the miscarriage rate in flight attendants who flew before the smoking ban. Flight attendants who flew before the smoking ban and participating in a study of health effects of secondhand smoke were asked to complete a reproductive health survey. We compared miscarriage rates of flight attendants to the general population using 2010 data from the Centers for Disease Control and Prevention. In our cohort of 145 female flight attendants exposed to secondhand smoke, there were 45 miscarriages (26%), compared with a 17.1% rate in the Centers for Disease Control and Prevention report (P = .002). There was no difference in secondhand smoke exposure between the flight attendants with miscarriage and the group without miscarriage (P = .93). This study found an increased incidence of miscarriage in flight attendants, which was unrelated to secondhand smoke exposure. Other factors, such as circadian rhythm disruption and radiation, may be related to these reproductive health findings and require further investigation. Copyright © 2017 Elsevier Inc. All rights reserved.

Blood and clonogenic hemopoietic cells of newts after the space flight

NASA Astrophysics Data System (ADS)

Michurina, T. V.; Domaratskaya, E. I.; Nikonova, T. M.; Khrushchov, N. G.

Ribbed newts were used for studying the effect of space flight on board of the biosatellite (Cosmos-2229) on blood and clonogenic hemopoietic cells. In blood of newts of the flight group, the relative proportion of neutrophils increased, whereas that of lymphocytes and eosinophils decreased. Space flight did not result in loss of the ability of newt blood cells to incorporate H^3-thymidine. Analysis of clonogenic hemopoietic cells was performed using the method of hemopoietic colony formation on cellulose acetate membranes implanted into the peritoneal cavity of irradiated newts. To analyze reconstitution of hemopoiesis after irradiation donor hemopoietic cells from flight or control newts were transplanted into irradiated newts whose hemopoietic organs were investigated. The newt can be considered an adequate model for studying hemopoiesis under the conditions of the space flight. Previous studies on rats subjected to 5- to 19-day space flights revealed a decrease in the number of clonogenic cells in their hemopoietic organs accompanied by specific changes in the precursor cell compartment and in blood /1,2/. Hence, it was interesting to analyze blood and hemopoietic tissue of lower vertebrates after a space flight and to compare the response to it of animals belonging to different taxonomic groups. We analyzed blood and clonogenic hemopoietic cells of ribbed newts, Pleurodeles waltl (age one year, weight 20-28 g) subjected to a 12-day space flight on board of a Cosmos-2229 biosatellite. The same animals were used in studies on limb and lens regeneration. The results were compared with those obtained with control groups of newts: (1) basic control, operated newts sacrificed on the day of biosatellite launching (BC); (2) synchronous control, operated newts kept in the laboratory under simulated space flight conditions (SC); and (3) intact newts (IC).

Effect of urinary pH and nicotine excretion rate on plasma nicotine during cigarette smoking and chewing nicotine gum

PubMed Central

Feyerabend, C.; Russell, M. A. H.

1978-01-01

1 Plasma nicotine levels produced by chewing nicotine gum were compared with those obtained by cigarette smoking under conditions of controlled urinary pH. 2 Although absorption was slower, plasma levels comparable to cigarette smoking were built up on 4 mg (but not 2 mg) nicotine gum. 3 Urinary excretion of nicotine was influenced markedly by pH and the rate of urine flow. 4 Plasma nicotine was higher under alkaline compared to acidic conditions (P < 0.001) but the rate of urinary nicotine excretion appeared to have little effect on the plasma level.

Post-Spaceflight (STS-135) Mouse Splenocytes Demonstrate Altered Activation Properties and Surface Molecule Expression

PubMed Central

Crucian, Brian; Sams, Clarence

2015-01-01

Alterations in immune function have been documented during or post-spaceflight and in ground based models of microgravity. Identification of immune parameters that are dysregulated during spaceflight is an important step in mitigating crew health risks during deep space missions. The in vitro analysis of leukocyte activity post-spaceflight in both human and animal species is primarily focused on lymphocytic function. This report completes a broader spectrum analysis of mouse lymphocyte and monocyte changes post 13 days orbital flight (mission STS-135). Analysis includes an examination in surface markers for cell activation, and antigen presentation and co-stimulatory molecules. Cytokine production was measured after stimulation with T-cell mitogen or TLR-2, TLR-4, or TLR-5 agonists. Splenocyte surface marker analysis immediate post-spaceflight and after in vitro culture demonstrated unique changes in phenotypic populations between the flight mice and matched treatment ground controls. Post-spaceflight splenocytes (flight splenocytes) had lower expression intensity of CD4+CD25+ and CD8+CD25+ cells, lower percentage of CD11c+MHC II+ cells, and higher percentage of CD11c+MHC I+ populations compared to ground controls. The flight splenocytes demonstrated an increase in phagocytic activity. Stimulation with ConA led to decrease in CD4+ population but increased CD4+CD25+ cells compared to ground controls. Culturing with TLR agonists led to a decrease in CD11c+ population in splenocytes isolated from flight mice compared to ground controls. Consequently, flight splenocytes with or without TLR-agonist stimulation showed a decrease in CD11c+MHC I+, CD11c+MHC II+, and CD11c+CD86+ cells compared to ground controls. Production of IFN-γ was decreased and IL-2 was increased from ConA stimulated flight splenocytes. This study demonstrated that expression of surface molecules can be affected by conditions of spaceflight and impaired responsiveness persists under culture conditions in vitro. PMID:25970640

Personality and morphological traits affect pigeon survival from raptor attacks.

PubMed

Santos, Carlos D; Cramer, Julia F; Pârâu, Liviu G; Miranda, Ana C; Wikelski, Martin; Dechmann, Dina K N

2015-10-22

Personality traits have recently been shown to impact fitness in different animal species, potentially making them similarly relevant drivers as morphological and life history traits along the evolutionary pathways of organisms. Predation is a major force of natural selection through its deterministic effects on individual survival, but how predation pressure has helped to shape personality trait selection, especially in free-ranging animals, remains poorly understood. We used high-precision GPS tracking to follow whole flocks of homing pigeons (Columba livia) with known personalities and morphology during homing flights where they were severely predated by raptors. This allowed us to determine how the personality and morphology traits of pigeons may affect their risk of being predated by raptors. Our survival model showed that individual pigeons, which were more tolerant to human approach, slower to escape from a confined environment, more resistant to human handling, with larger tarsi, and with lighter plumage, were more likely to be predated by raptors. We provide rare empirical evidence that the personality of prey influences their risk of being predated under free-ranging circumstances.

Personality and morphological traits affect pigeon survival from raptor attacks

PubMed Central

Santos, Carlos D.; Cramer, Julia F.; Pârâu, Liviu G.; Miranda, Ana C.; Wikelski, Martin; Dechmann, Dina K. N.

2015-01-01

Personality traits have recently been shown to impact fitness in different animal species, potentially making them similarly relevant drivers as morphological and life history traits along the evolutionary pathways of organisms. Predation is a major force of natural selection through its deterministic effects on individual survival, but how predation pressure has helped to shape personality trait selection, especially in free-ranging animals, remains poorly understood. We used high-precision GPS tracking to follow whole flocks of homing pigeons (Columba livia) with known personalities and morphology during homing flights where they were severely predated by raptors. This allowed us to determine how the personality and morphology traits of pigeons may affect their risk of being predated by raptors. Our survival model showed that individual pigeons, which were more tolerant to human approach, slower to escape from a confined environment, more resistant to human handling, with larger tarsi, and with lighter plumage, were more likely to be predated by raptors. We provide rare empirical evidence that the personality of prey influences their risk of being predated under free-ranging circumstances. PMID:26489437

Aggressive behavior and performance in the Tegu lizard Tupinambis merianae.

PubMed

Herrel, Anthony; Andrade, Denis V; de Carvalho, José Eduardo; Brito, Ananda; Abe, Augusto; Navas, Carlos

2009-01-01

Aggression is an important component of behavior in many animals and may be crucial to providing individuals with a competitive advantage when resources are limited. Although much is known about the effects of catecholamines and hormones on aggression, relatively few studies have examined the effects of physical performance on aggression. Here we use a large, sexually dimorphic teiid lizard to test whether individuals that show high levels of physical performance (bite force) are also more aggressive toward a potential threat (i.e., a human approaching the lizard). Our results show that independent of their sex, larger individuals with higher bite forces were indeed more aggressive. Moreover, our data show that individuals with higher bite forces tend to show decreased escape responses and are slower, providing evidence for a trade-off between fight and flight abilities. As bite force increased dramatically with body size, we suggest that large body size and bite force may reduce the threshold for an individual to engage in an aggressive encounter, allowing it to potentially gain or maintain resources and fight off predators while minimizing the risk of injury.

Ozone budgets from the Dynamics and Chemistry of Marine Stratocumulus experiment

NASA Technical Reports Server (NTRS)

Kawa, S. R.; Pearson, R., Jr.

1989-01-01

Measurements from the Dynamics and Chemistry of marine Stratocumulus experiment have been used to study components of the regional ozone budget. The surface destruction rate is determined by eddy correlation of ozone and vertical velocity measured by a low-flying aircraft. Significant variability is found in the measured surface resistance; it is partially correlated with friction velocity but appears to have other controlling influences as well. The mean resistance is 4190 s/m which is higher (slower destruction) than most previous estimates for seawater. Flux and mean measurements throughout the marine boundary layer are used to estimate the net rate of in situ photochemical production/destruction of ozone. Averaged over the flights, ozone concentration is found to be near steady state, and a net of photochemical destruction of 0.02-0.07 ng/cu m per sec is diagnosed. This is an important confirmation of photochemical model results for the remote marine boundary layer. Ozone vertical distributions above the boundary layer show a strongly layered structure with very sharp gradients. These distributions are possibly related to the stratospheric ozone source.

Age-Related Imbalance Is Associated With Slower Walking Speed: An Analysis From the National Health and Nutrition Examination Survey.

PubMed

Xie, Yanjun J; Liu, Elizabeth Y; Anson, Eric R; Agrawal, Yuri

Walking speed is an important dimension of gait function and is known to decline with age. Gait function is a process of dynamic balance and motor control that relies on multiple sensory inputs (eg, visual, proprioceptive, and vestibular) and motor outputs. These sensory and motor physiologic systems also play a role in static postural control, which has been shown to decline with age. In this study, we evaluated whether imbalance that occurs as part of healthy aging is associated with slower walking speed in a nationally representative sample of older adults. We performed a cross-sectional analysis of the previously collected 1999 to 2002 National Health and Nutrition Examination Survey (NHANES) data to evaluate whether age-related imbalance is associated with slower walking speed in older adults aged 50 to 85 years (n = 2116). Balance was assessed on a pass/fail basis during a challenging postural task-condition 4 of the modified Romberg Test-and walking speed was determined using a 20-ft (6.10 m) timed walk. Multivariable linear regression was used to evaluate the association between imbalance and walking speed, adjusting for demographic and health-related covariates. A structural equation model was developed to estimate the extent to which imbalance mediates the association between age and slower walking speed. In the unadjusted regression model, inability to perform the NHANES balance task was significantly associated with 0.10 m/s slower walking speed (95% confidence interval: -0.13 to -0.07; P < .01). In the multivariable regression analysis, inability to perform the balance task was significantly associated with 0.06 m/s slower walking speed (95% confidence interval: -0.09 to -0.03; P < .01), an effect size equivalent to 12 years of age. The structural equation model estimated that age-related imbalance mediates 12.2% of the association between age and slower walking speed in older adults. In a nationally representative sample, age-related balance limitation was associated with slower walking speed. Balance impairment may lead to walking speed declines. In addition, reduced static postural control and dynamic walking speed that occur with aging may share common etiologic origins, including the decline in visual, proprioceptive, and vestibular sensory and motor functions.

Increased Flight Altitudes among Migrating Golden Eagles Suggest Turbine Avoidance at a Rocky Mountain Wind Installation

PubMed Central

Johnston, Naira N.; Bradley, James E.; Otter, Ken A.

2014-01-01

Potential wind-energy development in the eastern Rocky Mountain foothills of British Columbia, Canada, raises concerns due to its overlap with a golden eagle (Aquila chrysaetos) migration corridor. The Dokie 1 Wind Energy Project is the first development in this area and stands as a model for other projects in the area because of regional consistency in topographic orientation and weather patterns. We visually tracked golden eagles over three fall migration seasons (2009–2011), one pre- and two post-construction, to document eagle flight behaviour in relation to a ridge-top wind energy development. We estimated three-dimensional positions of eagles in space as they migrated through our study site. Flight tracks were then incorporated into GIS to ascertain flight altitudes for eagles that flew over the ridge-top area (or turbine string). Individual flight paths were designated to a category of collision-risk based on flight altitude (e.g. flights within rotor-swept height; ≤150 m above ground) and wind speed (winds sufficient for the spinning of turbines; >6.8 km/h at ground level). Eagles were less likely to fly over the ridge-top area within rotor-swept height (risk zone) as wind speed increased, but were more likely to make such crosses under headwinds and tailwinds compared to western crosswinds. Most importantly, we observed a smaller proportion of flights within the risk zone at wind speeds sufficient for the spinning of turbines (higher-risk flights) during post-construction compared to pre-construction, suggesting that eagles showed detection and avoidance of turbines during migration. PMID:24671199

Increased flight altitudes among migrating golden eagles suggest turbine avoidance at a Rocky Mountain wind installation.

PubMed

Johnston, Naira N; Bradley, James E; Otter, Ken A

2014-01-01

Potential wind-energy development in the eastern Rocky Mountain foothills of British Columbia, Canada, raises concerns due to its overlap with a golden eagle (Aquila chrysaetos) migration corridor. The Dokie 1 Wind Energy Project is the first development in this area and stands as a model for other projects in the area because of regional consistency in topographic orientation and weather patterns. We visually tracked golden eagles over three fall migration seasons (2009-2011), one pre- and two post-construction, to document eagle flight behaviour in relation to a ridge-top wind energy development. We estimated three-dimensional positions of eagles in space as they migrated through our study site. Flight tracks were then incorporated into GIS to ascertain flight altitudes for eagles that flew over the ridge-top area (or turbine string). Individual flight paths were designated to a category of collision-risk based on flight altitude (e.g. flights within rotor-swept height; ≤150 m above ground) and wind speed (winds sufficient for the spinning of turbines; >6.8 km/h at ground level). Eagles were less likely to fly over the ridge-top area within rotor-swept height (risk zone) as wind speed increased, but were more likely to make such crosses under headwinds and tailwinds compared to western crosswinds. Most importantly, we observed a smaller proportion of flights within the risk zone at wind speeds sufficient for the spinning of turbines (higher-risk flights) during post-construction compared to pre-construction, suggesting that eagles showed detection and avoidance of turbines during migration.

Adults with Dyslexia Demonstrate Space-Based and Object-Based Covert Attention Deficits: Shifting Attention to the Periphery and Shifting Attention between Objects in the Left Visual Field

ERIC Educational Resources Information Center

Buchholz, J.; Davies, A.A.

2005-01-01

Performance on a covert visual attention task is compared between a group of adults with developmental dyslexia (specifically phonological difficulties) and a group of age and IQ matched controls. The group with dyslexia were generally slower to detect validly-cued targets. Costs of shifting attention toward the periphery when the target was…

An accelerometry-based comparison of 2 robotic assistive devices for treadmill training of gait.

PubMed

Regnaux, Jean-Philippe; Saremi, Kaveh; Marehbian, Jon; Bussel, Bernard; Dobkin, Bruce H

2008-01-01

Two commercial robotic devices, the Gait Trainer (GT) and the Lokomat (LOKO), assist task-oriented practice of walking. The gait patterns induced by these motor-driven devices have not been characterized and compared. A healthy participant chose the most comfortable gait pattern on each device and for treadmill (TM) walking at 1, 2 (maximum for the GT), and 3 km/h and over ground at similar speeds. A system of accelerometers on the thighs and feet allowed the calculation of spatiotemporal features and accelerations during the gait cycle. At the 1 and 2 km/h speed settings, single-limb stance times were prolonged on the devices compared with overground walking. Differences on the LOKO were decreased by adjusting the hip and knee angles and step length. At the 3 km/h setting, the LOKO approximated the participant's overground parameters. Irregular accelerations and decelerations from toe-off to heel contact were induced by the devices, especially at slower speeds. The LOKO and GT impose mechanical constraints that may alter leg accelerations-decelerations during stance and swing phases, as well as stance duration, especially at their slower speed settings, that are not found during TM and overground walking. The potential impact of these perturbations on training to improve gait needs further study.

RNA editing of the GABAA receptor α3 subunit alters the functional properties of recombinant receptors

PubMed Central

Nimmich, Mitchell L.; Heidelberg, Laura S.; Fisher, Janet L.

2009-01-01

RNA editing provides a post-transcriptional mechanism to increase structural heterogeneity of gene products. Recently, the α3 subunit of the GABAA receptors has been shown to undergo RNA editing. As a result, a highly conserved isoleucine residue in the third transmembrane domain is replaced with a methionine. To determine the effect of this structural change on receptor function, we compared the GABA sensitivity, pharmacological properties and macroscopic kinetics of recombinant receptors containing either the edited or unedited forms of the α3 subunit along with β3 and γ2L. Editing substantially altered the GABA sensitivity and deactivation rate of the receptors, with the unedited form showing a lower GABA EC50 and slower decay. Comparable effects were observed with a mutation at the homologous location in the α1 subunit, suggesting a common role for this site in regulation of channel gating. Except for the response to GABA, the pharmacological properties of the receptor were unaffected by editing, with similar enhancement by a variety of modulators. Since RNA editing of the α3 subunit increases through development, our findings suggest that GABAergic neurotransmission may be more effective early in development, with greater GABA sensitivity and slower decay rates conferred by the unedited α3 subunit. PMID:19367790

Complex word reading in Dutch deaf children and adults.

PubMed

van Hoogmoed, Anne H; Knoors, Harry; Schreuder, Robert; Verhoeven, Ludo

2013-03-01

Children who are deaf are often delayed in reading comprehension. This delay could be due to problems in morphological processing during word reading. In this study, we investigated whether 6th grade deaf children and adults are delayed in comparison to their hearing peers in reading complex derivational words and compounds compared to monomorphemic words. The results show that deaf children are delayed in reading both derivational words and compounds as compared to hearing children, while both deaf and hearing adults performed equally well on a lexical decision task. However, deaf adults generally showed slower reaction times than hearing adults. For both deaf and hearing children, derivational words were more difficult than compounds, as reflected in hearing children's slower reaction times and in deaf children's lower accuracy scores. This finding likely reflects deaf children's lack of familiarity with the meaning of the bound morphemes attached to the stems in derivational words. Therefore, it might be beneficial to teach deaf children the meaning of bound morphemes and to train them to use morphology in word reading. Moreover, these findings imply that it is important to focus on both monomorphemic and polymorphemic words when assessing word reading ability in deaf children. Copyright © 2012 Elsevier Ltd. All rights reserved.

Growth and proteomic analysis of tomato fruit under partial root-zone drying.

PubMed

Marjanović, Milena; Stikić, Radmila; Vucelić-Radović, Biljana; Savić, Sladjana; Jovanović, Zorica; Bertin, Nadia; Faurobert, Mireille

2012-06-01

The effects of partial root-zone drying (PRD) on tomato fruit growth and proteome in the pericarp of cultivar Ailsa Craig were investigated. The PRD treatment was 70% of water applied to fully irrigated (FI) plants. PRD reduced the fruit number and slightly increased the fruit diameter, whereas the total fruit fresh weight (FW) and dry weight (DW) per plant did not change. Although the growth rate was higher in FI than in PRD fruits, the longer period of cell expansion resulted in bigger PRD fruits. Proteins were extracted from pericarp tissue at two fruit growth stages (15 and 30 days post-anthesis [dpa]), and submitted to proteomic analysis including two-dimensional gel electrophoresis and mass spectrometry for identification. Proteins related to carbon and amino acid metabolism indicated that slower metabolic flux in PRD fruits may be the cause of a slower growth rate compared to FI fruits. The increase in expression of the proteins related to cell wall, energy, and stress defense could allow PRD fruits to increase the duration of fruit growth compared to FI fruits. Upregulation of some of the antioxidative enzymes during the cell expansion phase of PRD fruits appears to be related to their role in protecting fruits against the mild stress induced by PRD.

Reduced proliferation and osteocalcin expression in osteoblasts of male idiopathic osteoporosis.

PubMed

Ruiz-Gaspà, Sílvia; Blanch-Rubió, Josep; Ciria-Recasens, Manuel; Monfort, Jordi; Tío, Laura; Garcia-Giralt, Natàlia; Nogués, Xavier; Monllau, Joan C; Carbonell-Abelló, Jordi; Pérez-Edo, Lluis

2010-03-01

Osteoporosis is characterized by low bone mineral density (BMD), resulting in increasing susceptibility to bone fractures. In men, it has been related to some diseases and toxic habits, but in some instances the cause of the primary--or idiopathic--osteoporosis is not apparent. In a previous study, our group compared histomorphometric measurements in cortical and cancellous bones from male idiopathic osteoporosis (MIO) patients to those of control subjects and found reduced bone formation without major differences in bone resorption. To confirm these results, this study analyzed the etiology of this pathology, examining the osteoblast behavior in vitro. We compared two parameters of osteoblast activity in MIO patients and controls: osteoblastic proliferation and gene expression of COL1A1 and osteocalcin, in basal conditions and with vitamin D(3) added. All these experiments were performed from a first-passage osteoblastic culture, obtained from osteoblasts that had migrated from the transiliac explants to the plate. The results suggested that the MIO osteoblast has a slower proliferation rate and decreased expression of genes related to matrix formation, probably due to a lesser or slower response to some stimulus. We concluded that, contrary to female osteoporosis, in which loss of BMD is predominantly due to increased resorption, low BMD in MIO seems to be due to an osteoblastic defect.

Acoustic Predictions of Manned and Unmanned Rotorcraft Using the Comprehensive Analytical Rotorcraft Model for Acoustics (CARMA) Code System

NASA Technical Reports Server (NTRS)

Boyd, D. Douglas, Jr.; Burley, Casey L.; Conner, David A.

2005-01-01

The Comprehensive Analytical Rotorcraft Model for Acoustics (CARMA) is being developed under the Quiet Aircraft Technology Project within the NASA Vehicle Systems Program. The purpose of CARMA is to provide analysis tools for the design and evaluation of efficient low-noise rotorcraft, as well as support the development of safe, low-noise flight operations. The baseline prediction system of CARMA is presented and current capabilities are illustrated for a model rotor in a wind tunnel, a rotorcraft in flight and for a notional coaxial rotor configuration; however, a complete validation of the CARMA system capabilities with respect to a variety of measured databases is beyond the scope of this work. For the model rotor illustration, predicted rotor airloads and acoustics for a BO-105 model rotor are compared to test data from HART-II. For the flight illustration, acoustic data from an MD-520N helicopter flight test, which was conducted at Eglin Air Force Base in September 2003, are compared with CARMA full vehicle flight predictions. Predicted acoustic metrics at three microphone locations are compared for limited level flight and descent conditions. Initial acoustic predictions using CARMA for a notional coaxial rotor system are made. The effect of increasing the vertical separation between the rotors on the predicted airloads and acoustic results are shown for both aerodynamically non-interacting and aerodynamically interacting rotors. The sensitivity of including the aerodynamic interaction effects of each rotor on the other, especially when the rotors are in close proximity to one another is initially examined. The predicted coaxial rotor noise is compared to that of a conventional single rotor system of equal thrust, where both are of reasonable size for an unmanned aerial vehicle (UAV).

A rapid rotation to an inverted seated posture inhibits muscle force, activation, heart rate and blood pressure.

PubMed

Johar, Pramod; Grover, Varun; DiSanto, Mario C; Button, Duane C; Behm, David G

2013-08-01

Although previous studies have demonstrated neuromuscular and cardiovascular changes with slow inversion rates, emergencies, such as overturned vehicles and helicopters can occur rapidly. The purpose of this study was to investigate changes in neuromuscular and cardiovascular responses with rapid (1 s) and slower (3 s) transitions from upright to inverted seated positions. Twenty-two subjects performed separate and concurrent unilateral elbow flexion and leg extension maximal voluntary contractions (MVCs) for 6 s in an upright seated position and when inverted with 1 and 3 s rotations. Elbow flexion and leg extension force; biceps, triceps, quadriceps and hamstrings electromyographic (EMG) activity, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured. Whether the elbow flexion or leg extension contractions occurred concurrently or individually, significant (p < 0.05) decreases in MVC force and EMG activity were found when inverted within 1 and 3 s rotations as compared to upright. Triceps and hamstrings EMG activity (p < 0.05) decreased when inverted within 1 s rotation as compared to upright. Following rotation, the maintenance of the inverted position (3-6 s timepoint) resulted in a significant (p < 0.05) increase in leg extension MVC as compared to the initial second of rotation to inversion. HR, SBP and DBP demonstrated (p < 0.001) decreases when inverted within 1 and 3 s rotations as compared to upright. In conclusion, this is the first study to show that irrespective of rotation speed, inversion inhibited neuromuscular and cardiovascular responses, similar to the more deliberate, slower rotation of previous inversion studies.

Primary Arthrodesis versus Open Reduction and Internal Fixation for Low-Energy Lisfranc Injuries in a Young Athletic Population.

PubMed

Cochran, Grant; Renninger, Christopher; Tompane, Trevor; Bellamy, Joseph; Kuhn, Kevin

2017-09-01

There are 2 Level I studies comparing open reduction and internal fixation (ORIF) and primary arthrodesis (PA) in high-energy Lisfranc injuries. There are no studies comparing ORIF and PA in young athletic patients with low-energy injuries. All operatively managed low-energy Lisfranc injuries sustained by active duty military personnel at a single institution were identified from 2010 to 2015. The injury pattern, method of treatment, and complications were reviewed. Implant removal rates, fitness test scores, return to military duty rates, and Foot and Ankle Ability Measure (FAAM) scores were compared. Thirty-two patients were identified with the average age of 28 years. PA was performed in 14 patients with ORIF in 18. The PA group returned to full duty at an average of 4.5 months whereas the ORIF group returned at an average of 6.7 months ( P = .0066). The PA group ran their fitness test an average of 9 seconds per mile slower than their preoperative average whereas the ORIF group ran it an average of 39 seconds slower per mile ( P = .032). There were no differences between the 2 groups in the FAAM scores at an average of 35 months. Implant removal was performed in 15 (83%) in the ORIF group and 2 (14%) in the PA group ( P = .005). Low-energy Lisfranc injuries treated with primary arthrodesis had a lower implant removal rate, an earlier return to full military activity, and better fitness test scores after 1 year, but there was no difference in FAAM scores after 3 years. Level III, comparative cohort study.

The ability of people with Parkinson's disease to modify dual-task performance in response to instructions during simple and complex walking tasks.

PubMed

Kelly, Valerie E; Shumway-Cook, Anne

2014-01-01

Gait impairments are a common and consequential motor symptom in Parkinson's disease (PD). A cognitive strategy that incorporates instructions to concentrate on specific parameters of walking is an effective approach to gait rehabilitation for persons with PD during single-task and simple dual-task walking conditions. This study examined the ability to modify dual-task walking in response to instructions during a complex walking task in people with PD compared to healthy older adults (HOA). Eleven people with PD and twelve HOA performed a cognitive task while walking with either a usual base or a narrow base of support. Dual-task walking and cognitive task performance were characterized under two conditions-when participants were instructed focus on walking and when they were instructed to focus on the cognitive task. During both usual base and narrow base walking, instructions affected cognitive task response latency, with slower performance when instructed to focus on walking compared to the cognitive task. Regardless of task or instructions, cognitive task performance was slower in participants with PD compared to HOA. During usual base walking, instructions influenced gait speed for both people with PD and HOA, with faster gait speed when instructed to focus on walking compared to the cognitive task. In contrast, during the narrow base walking, instructions affected gait speed only for HOA, but not for people with PD. This suggests that among people with PD the ability to modify walking in response to instructions depends on the complexity of the walking task.

Flight test derived heating math models for critical locations on the orbiter during reentry

NASA Technical Reports Server (NTRS)

Hertzler, E. K.; Phillips, P. W.

1983-01-01

An analysis technique was developed for expanding the aerothermodynamic envelope of the Space Shuttle without subjecting the vehicle to sustained flight at more stressing heating conditions. A transient analysis program was developed to take advantage of the transient maneuvers that were flown as part of this analysis technique. Heat rates were derived from flight test data for various locations on the orbiter. The flight derived heat rates were used to update heating models based on predicted data. Future missions were then analyzed based on these flight adjusted models. A technique for comparing flight and predicted heating rate data and the extrapolation of the data to predict the aerothermodynamic environment of future missions is presented.

Assessment of Turbulent CFD Against STS-128 Hypersonic Flight Data

NASA Technical Reports Server (NTRS)

Wood, William A.; Kleb, William L.; Hyatt, Andrew J.

2010-01-01

Turbulent CFD simulations are compared against surface temperature measurements of the space shuttle orbiter windward tiles at reentry flight conditions. Algebraic turbulence models are used within both the LAURA and DPLR CFD codes. The flight data are from temperature measurements obtained by seven thermocouples during the STS-128 mission (September 2009). The flight data indicate boundary layer transition onset over the Mach number range 13.5{15.5, depending upon the location on the vehicle. But the boundary layer flow appeared to be transitional down through Mach 12, based upon the flight data and CFD trends. At Mach 9 the simulations match the flight data on average within 20 F/11 C, where typical surface temperatures were approximately 1600 F/870 C.

The FLIGHT Drosophila RNAi database

PubMed Central

Bursteinas, Borisas; Jain, Ekta; Gao, Qiong; Baum, Buzz; Zvelebil, Marketa

2010-01-01

FLIGHT (http://flight.icr.ac.uk/) is an online resource compiling data from high-throughput Drosophila in vivo and in vitro RNAi screens. FLIGHT includes details of RNAi reagents and their predicted off-target effects, alongside RNAi screen hits, scores and phenotypes, including images from high-content screens. The latest release of FLIGHT is designed to enable users to upload, analyze, integrate and share their own RNAi screens. Users can perform multiple normalizations, view quality control plots, detect and assign screen hits and compare hits from multiple screens using a variety of methods including hierarchical clustering. FLIGHT integrates RNAi screen data with microarray gene expression as well as genomic annotations and genetic/physical interaction datasets to provide a single interface for RNAi screen analysis and datamining in Drosophila. PMID:20855970

Recent findings in cardiovascular physiology with space travel.

PubMed

Hughson, Richard L

2009-10-01

The cardiovascular system undergoes major changes in stress with space flight primarily related to the elimination of the head-to-foot gravitational force. A major observation has been that the central venous pressure is not elevated early in space flight yet stroke volume is increased at least early in flight. Recent observations demonstrate that heart rate remains lower during the normal daily activities of space flight compared to Earth-based conditions. Structural and functional adaptations occur in the vascular system that could result in impaired response with demands of physical exertion and return to Earth. Cardiac muscle mass is reduced after flight and contractile function may be altered. Regular and specific countermeasures are essential to maintain cardiovascular health during long-duration space flight.

Predicted and flight test results of the performance, stability and control of the space shuttle from reentry to landing

NASA Technical Reports Server (NTRS)

Kirsten, P. W.; Richardson, D. F.; Wilson, C. M.

1983-01-01

Aerodynaic performance, stability and control data obtained from the first five reentries of the Space Shuttle orbiter are given. Flight results are compared to pedicted data from Mach 26.4 to Mach 0.4. Differences between flight and predicted data as well as probable causes for the discrepancies are given.

Shuttle SRB preflight/post-flight thermal assessment

NASA Technical Reports Server (NTRS)

1985-01-01

The development of the thermal protection system for the Solid Rocket Booster is reported. Tests and analytical efforts were conducted and new problems are continually attacked and solved. During the first six Shuttle flights it was necessary to make a final thermal assessment of the TPS and structural systems temperatures. The thermal assessments were made and are compared with post flight data.

Method of Curved Models and Its Application to the Study of Curvilinear Flight of Airships. Part II

NASA Technical Reports Server (NTRS)

Gourjienko, G A

1937-01-01

This report compares the results obtained by the aid of curved models with the results of tests made by the method of damped oscillations, and with flight tests. Consequently we shall be able to judge which method of testing in the tunnel produces results that are in closer agreement with flight test results.

Automated Flight Routing Using Stochastic Dynamic Programming

NASA Technical Reports Server (NTRS)

Ng, Hok K.; Morando, Alex; Grabbe, Shon

2010-01-01

Airspace capacity reduction due to convective weather impedes air traffic flows and causes traffic congestion. This study presents an algorithm that reroutes flights in the presence of winds, enroute convective weather, and congested airspace based on stochastic dynamic programming. A stochastic disturbance model incorporates into the reroute design process the capacity uncertainty. A trajectory-based airspace demand model is employed for calculating current and future airspace demand. The optimal routes minimize the total expected traveling time, weather incursion, and induced congestion costs. They are compared to weather-avoidance routes calculated using deterministic dynamic programming. The stochastic reroutes have smaller deviation probability than the deterministic counterpart when both reroutes have similar total flight distance. The stochastic rerouting algorithm takes into account all convective weather fields with all severity levels while the deterministic algorithm only accounts for convective weather systems exceeding a specified level of severity. When the stochastic reroutes are compared to the actual flight routes, they have similar total flight time, and both have about 1% of travel time crossing congested enroute sectors on average. The actual flight routes induce slightly less traffic congestion than the stochastic reroutes but intercept more severe convective weather.

Validations of Coupled CSD/CFD and Particle Vortex Transport Method for Rotorcraft Applications: Hover, Transition, and High Speed Flights

NASA Technical Reports Server (NTRS)

Anusonti-Inthra, Phuriwat

2010-01-01

This paper presents validations of a novel rotorcraft analysis that coupled Computational Fluid Dynamics (CFD), Computational Structural Dynamics (CSD), and Particle Vortex Transport Method (PVTM) methodologies. The CSD with associated vehicle trim analysis is used to calculate blade deformations and trim parameters. The near body CFD analysis is employed to provide detailed near body flow field information which is used to obtain high-fidelity blade aerodynamic loadings. The far field wake dominated region is simulated using the PVTM analysis which provides accurate prediction of the evolution of the rotor wake released from the near body CFD domains. A loose coupling methodology between the CSD and CFD/PVTM modules are used with appropriate information exchange amongst the CSD/CFD/PVTM modules. The coupled CSD/CFD/PVTM methodology is used to simulate various rotorcraft flight conditions (i.e. hover, transition, and high speed flights), and the results are compared with several sets of experimental data. For the hover condition, the results are compared with hover data for the HART II rotor tested at DLR Institute of Flight Systems, Germany. For the forward flight conditions, the results are validated with the UH-60A flight test data.

Flight experience with flight control redundancy management

NASA Technical Reports Server (NTRS)

Szalai, K. J.; Larson, R. R.; Glover, R. D.

1980-01-01

Flight experience with both current and advanced redundancy management schemes was gained in recent flight research programs using the F-8 digital fly by wire aircraft. The flight performance of fault detection, isolation, and reconfiguration (FDIR) methods for sensors, computers, and actuators is reviewed. Results of induced failures as well as of actual random failures are discussed. Deficiencies in modeling and implementation techniques are also discussed. The paper also presents comparison off multisensor tracking in smooth air, in turbulence, during large maneuvers, and during maneuvers typical of those of large commercial transport aircraft. The results of flight tests of an advanced analytic redundancy management algorithm are compared with the performance of a contemporary algorithm in terms of time to detection, false alarms, and missed alarms. The performance of computer redundancy management in both iron bird and flight tests is also presented.

Three Dimensional Aerodynamic Analysis of a High-Lift Transport Configuration

NASA Technical Reports Server (NTRS)

Dodbele, Simha S.

1993-01-01

Two computational methods, a surface panel method and an Euler method employing unstructured grid methodology, were used to analyze a subsonic transport aircraft in cruise and high-lift conditions. The computational results were compared with two separate sets of flight data obtained for the cruise and high-lift configurations. For the cruise configuration, the surface pressures obtained by the panel method and the Euler method agreed fairly well with results from flight test. However, for the high-lift configuration considerable differences were observed when the computational surface pressures were compared with the results from high-lift flight test. On the lower surface of all the elements with the exception of the slat, both the panel and Euler methods predicted pressures which were in good agreement with flight data. On the upper surface of all the elements the panel method predicted slightly higher suction compared to the Euler method. On the upper surface of the slat, pressure coefficients obtained by both the Euler and panel methods did not agree with the results of the flight tests. A sensitivity study of the upward deflection of the slat from the 40 deg. flap setting suggested that the differences in the slat deflection between the computational model and the flight configuration could be one of the sources of this discrepancy. The computation time for the implicit version of the Euler code was about 1/3 the time taken by the explicit version though the implicit code required 3 times the memory taken by the explicit version.

A Limited Rotary-Wing Flight Investigation of Hyperstereo in Helmet-Mounted Display Designs

DTIC Science & Technology

2009-07-01

when compared to current and near-term I2 systems with a direct optical linkage. In summary, the current binocular I2 HMD design of ANVIS, which...terms of visual and optical performance. This assessment was performed by measuring a number of system parameters and by comparing the obtained...to subject #2 who had 800 NVG flight hours. Interestingly, across all maneuvers for which the hyperstereo HMD was asked to be compared to ANVIS

Implementation of an Adaptive Controller System from Concept to Flight Test

NASA Technical Reports Server (NTRS)

Larson, Richard R.; Burken, John J.; Butler, Bradley S.; Yokum, Steve

2009-01-01

The National Aeronautics and Space Administration (NASA) at the Dryden Flight Research Center (DFRC) has been conducting flight-test research using an F-15 aircraft (figure 1). This aircraft has been specially modified to interface a neural net (NN) controller as part of a single-string Airborne Research Test System (ARTS) computer with the existing quad-redundant flight control system (FCC) shown in figure 2. The NN commands are passed to FCC channels 2 and 4 and are cross channel data linked (CCDL) to the other computers as shown. Numerous types of fault-detection monitors exist in the FCC when the NN mode is engaged; these monitors would cause an automatic disengagement of the NN in the event of a triggering fault. Unfortunately, these monitors still may not prevent a possible NN hard-over command from coming through to the control laws. Therefore, an additional and unique safety monitor was designed for a single-string source that allows authority at maximum actuator rates but protects the pilot and structural loads against excessive g-limits in the case of a NN hard-over command input. This additional monitor resides in the FCCs and is executed before the control laws are computed. This presentation describes a "floating limiter" (FL) concept that was developed and successfully test-flown for this program (figure 3). The FL computes the rate of change of the NN commands that are input to the FCC from the ARTS. A window is created with upper and lower boundaries, which is constantly "floating" and trying to stay centered as the NN command rates are changing. The limiter works by only allowing the window to move at a much slower rate than those of the NN commands. Anywhere within the window, however, full rates are allowed. If a rate persists in one direction, it will eventually "hit" the boundary and be rate-limited to the floating limiter rate. When this happens, a persistent counter begins and after a limit is reached, a NN disengage command is generated. The tunable metrics for the FL are (1) window size, (2) drift rate, and (3) persistence counter. Ultimate range limits are also included in case the NN command should drift slowly to a limit value that would cause the FL to be defeated. The FL has proven to work as intended. Both high-g transients and excessive structural loads are controlled with NN hard-over commands. This presentation discusses the FL design features and presents test cases. Simulation runs are included to illustrate the dramatic improvement made to the control of NN hard-over effects. A mission control room display from a flight playback is presented to illustrate the neural net fault display representation. The FL is very adaptable to various requirements and is independent of flight condition. It should be considered as a cost-effective safety monitor to control single-string inputs in general.

Orbital experiment ``Gravisensor'': phototropic reactions of the moss Physcomitrella patens to different types of LED lighting.

NASA Astrophysics Data System (ADS)

Nikitin, Vladimir; Berkovich, Yuliy A.; Skripnikov, Alexander; Zyablova, Natalya; Mukhoyan, Makar; Emelianov, Grigory

The experiment was conducted on Russian Biological Satelite Bion-M #1 19.04-19.05 2013. Five transparent plastic cultural flasks were placed in five light isolated sections of Biocont-B2 cylindrical container with inner diameter of 120 mm and height of 230 mm. In four sections the flasks could be illuminated by top or side LED with wavelength of 458 nm, 630 nm, 730 nm, and white (color temperature 5000° K, peaks 453, 559 nm). Photon flux in each variant was 15 umol/(m2c). In the fifth section the flask with the shoots was in conditions of constant dark. Each section was equipped with its own video camera module. Cameras, video recorder and lighting were managed by micro controller. 12 days before launch, 5 tips of the moss shoots were explanted at each of the five flasks on the agar medium with nutrient components and were cultivated under white fluorescent lamps at 12 hour photo period till the launch. After entering the orbit and during next 14 days of flight top LEDs were turned on above the flasks. Then for the following 14 days of flight the side LEDs of similar wavelength were turned on. The moss gametophores were cultivated at 12-h photoperiod. During the experiment on an hourly basis a video recording of the moss was performed. Similar equipment was used for ground control. After the experiment video files were used to produce separate time-lapse films for each flask using AviSynth program. In flight the shoots demonstrated the maximum growth speed with far red lighting and slower speed with white lighting. With blue and red lighting after switching to side light stimuli the growth of shoots almost stopped. In the dark the shoots continued to grow until the 13 day after launch of the satellite, then their growth stopped. In ground control the relation of growth rate with various LEDs remained basically the same, with the exception of side blue lighting, where the shoots demonstrated considerable vertical growth. In flight the angle of inclination towards the light source was maximal (about 90º) with white lighting, and somewhat smaller with 730 nm. Under red and blue light the angle of phototropic inclination was difficult to measure due to poor growth of the shoots.In ground control the growth rate under blue light was several times higher, than in flight and final degree of inclination of the shoot tip came to about 10º. In ground control under side red lighting the growth was weak, while demonstrating a pronounced phototropic bend of 90º. In ground control in the dark a vertical growth of one shoot was observed with the rate somewhat larger, than in flight variant. Data on the dynamics of inclination of experimental and control plants are presented. The acquired data will be used to analyse the mechanisms of phototropic growth changes of moss shoots.

Test-engine and inlet performance of an aircraft used for investigating flight effects on fan noise

NASA Technical Reports Server (NTRS)

Golub, R. A.; Preisser, J. S.

1984-01-01

As part of the NASA Flight Effects on Fan Noise Program, a Grumman OV-1B Mohawk aircraft was modified to carry a modified and instrumented Pratt & Whitney JT15D-1 turbofan engine. Onboard flight data, together with simultaneously measured farfield acoustic data, comprise a flight data base to which JT15D-1 static and wind-tunnel data are compared. The overall objective is to improve the ability to use ground-based facilities for the prediction of flight inlet radiated noise. This report describes the hardware and presents performance results for the research engine.

Space transportation system biomedical operations support study

NASA Technical Reports Server (NTRS)

White, S. C.

1983-01-01

The shift of the Space Transportation System (STS) flight tests of the orbiter vehicle to the preparation and flight of the payloads is discussed. Part of this change is the transition of the medical and life sciences aspects of the STS flight operations to reflect the new state. The medical operations, the life sciences flight experiments support requirements and the intramural research program expected to be at KSC during the operational flight period of the STS and a future space station are analyzed. The adequacy of available facilities, plans, and resources against these future needs are compared; revisions and/or alternatives where appropriate are proposed.

Orbiter entry leeside heat-transfer data analysis

NASA Technical Reports Server (NTRS)

Throckmorton, D. A.; Zoby, E. V.

1983-01-01

Heat-transfer data measured along the Space Shuttle Orbiter's leeward centerline and over the wing leeside surface during the STS-2 and STS-3 mission entries are presented. The flight data are compared with available wind-tunnel results. Flight heating levels are, in general, lower than those which are inferred from the wind-tunnel results. This result is apparently due to the flight leeside flowfield remaining laminar over a larger Reynolds number range than that of corresponding ground test results. The flight/wind-tunnel data comparisons confirm the adequacy of, and conservatism embodied in, the direct application of wind-tunnel data at flight conditions for the design of Orbiter leeside thermal protection.

Fatigue-test acceleration with flight-by-flight loading and heating to simulate supersonic-transport operation

NASA Technical Reports Server (NTRS)

Imig, L. A.; Garrett, L. E.

1973-01-01

Possibilities for reducing fatigue-test time for supersonic-transport materials and structures were studied in tests with simulated flight-by-flight loading. In order to determine whether short-time tests were feasible, the results of accelerated tests (2 sec per flight) were compared with the results of real-time tests (96 min per flight). The effects of design mean stress, the stress range for ground-air-ground cycles, simulated thermal stress, the number of stress cycles in each flight, and salt corrosion were studied. The flight-by-flight stress sequences were applied to notched sheet specimens of Ti-8Al-1Mo-1V and Ti-6Al-4V titanium alloys. A linear cumulative-damage analysis accounted for large changes in stress range of the simulated flights but did not account for the differences between real-time and accelerated tests. The fatigue lives from accelerated tests were generally within a factor of two of the lives from real-time tests; thus, within the scope of the investigation, accelerated testing seems feasible.

Design and Flight Evaluation of a New Force-Based Flow Angle Probe

NASA Technical Reports Server (NTRS)

Corda, Stephen; Vachon, Michael Jacob

2006-01-01

A novel force-based flow angle probe was designed and flight tested on the NASA F-15B Research Testbed aircraft at NASA Dryden Flight Research Center. The prototype flow angle probe is a small, aerodynamic fin that has no moving parts. Forces on the prototype flow angle probe are measured with strain gages and correlated with the local flow angle. The flow angle probe may provide greater simplicity, greater robustness, and better access to flow measurements in confined areas relative to conventional moving vane-type flow angle probes. Flight test data were obtained at subsonic, transonic, and supersonic Mach numbers to a maximum of Mach 1.70. Flight conditions included takeoff, landing, straight and level flight, flight at higher aircraft angles of attack, and flight at elevated g-loadings. Flight test maneuvers included angle-of-attack and angle-of-sideslip sweeps. The flow angle probe-derived flow angles are compared with those obtained with a conventional moving vane probe. The flight tests validated the feasibility of a force-based flow angle measurement system.

Esophageal function testing using multichannel intraluminal impedance.

PubMed

Srinivasan, R; Vela, M F; Katz, P O; Tutuian, R; Castell, J A; Castell, D O

2001-03-01

Multichannel intraluminal impedance (MII) is a new technique for evaluation of bolus transport. We evaluated esophageal function using bolus transport time (BTT) and contraction wave velocity (CWV) of liquid, semisolid, and solid boluses. Ten healthy subjects underwent MII swallow evaluation with various boluses of sterile water (pH 5), applesauce, three different sized marshmallows, and iced and 130 degrees F water. The effect of bethanechol was also studied. There was no difference in BTT or CWV for all water volumes from 1 to 20 ml. There was significant linear increase of BTT with progressively larger volumes of applesauce, and BTT of applesauce was longer than for water. BTT was significantly longer with large marshmallows vs. small and medium and was longer than for water. BTT for iced water was similar to 130 degrees F water. Applesauce showed a significant linear decrease of CWV with progressively larger volumes and was slower than water. Marshmallow showed significantly slower CWV with the large vs. small, and CWV for ice water was significantly slower than 130 degrees F water. Therefore, BTT of liquid is constant, whereas BTT of semisolid and solid are volume dependent and longer than liquids. CWV of semisolids and solids are slower than liquids. CWV of cold liquids is slower than warm liquids. MII can be used as a discriminating test of esophageal function.

Clutter and conspecifics: a comparison of their influence on echolocation and flight behaviour in Daubenton's bat, Myotis daubentonii.

PubMed

Fawcett, Kayleigh; Ratcliffe, John M

2015-03-01

We compared the influence of conspecifics and clutter on echolocation and flight speed in the bat Myotis daubentonii. In a large room, actual pairs of bats exhibited greater disparity in peak frequency (PF), minimum frequency (F MIN) and call period compared to virtual pairs of bats, each flying alone. Greater inter-individual disparity in PF and F MIN may reduce acoustic interference and/or increase signal self-recognition in the presence of conspecifics. Bats flying alone in a smaller flight room, to simulate a more cluttered habitat as compared to the large flight room, produced calls of shorter duration and call period, lower intensity, and flew at lower speeds. In cluttered space, shorter call duration should reduce masking, while shorter call period equals more updates to the bat's auditory scene. Lower intensity likely reflects reduced range detection requirements, reduced speed the demands of flying in clutter. Our results show that some changes (e.g. PF separation) are associated with conspecifics, others with closed habitat (e.g. reduced call intensity). However, we demonstrate that call duration, period, and flight speed appear similarly influenced by conspecifics and clutter. We suggest that some changes reduce conspecific interference and/or improve self-recognition, while others demonstrate that bats experience each other like clutter.

Reduced flight-to-light behaviour of moth populations exposed to long-term urban light pollution

PubMed Central

Ebert, Dieter

2016-01-01

The globally increasing light pollution is a well-recognized threat to ecosystems, with negative effects on human, animal and plant wellbeing. The most well-known and widely documented consequence of light pollution is the generally fatal attraction of nocturnal insects to artificial light sources. However, the evolutionary consequences are unknown. Here we report that moth populations from urban areas with high, globally relevant levels of light pollution over several decades show a significantly reduced flight-to-light behaviour compared with populations of the same species from pristine dark-sky habitats. Using a common garden setting, we reared moths from 10 different populations from early-instar larvae and experimentally compared their flight-to-light behaviour under standardized conditions. Moths from urban populations had a significant reduction in the flight-to-light behaviour compared with pristine populations. The reduced attraction to light sources of ‘city moths' may directly increase these individuals' survival and reproduction. We anticipate that it comes with a reduced mobility, which negatively affects foraging as well as colonization ability. As nocturnal insects are of eminent significance as pollinators and the primary food source of many vertebrates, an evolutionary change of the flight-to-light behaviour thereby potentially cascades across species interaction networks. PMID:27072407

Reduced flight-to-light behaviour of moth populations exposed to long-term urban light pollution.

PubMed

Altermatt, Florian; Ebert, Dieter

2016-04-01

The globally increasing light pollution is a well-recognized threat to ecosystems, with negative effects on human, animal and plant wellbeing. The most well-known and widely documented consequence of light pollution is the generally fatal attraction of nocturnal insects to artificial light sources. However, the evolutionary consequences are unknown. Here we report that moth populations from urban areas with high, globally relevant levels of light pollution over several decades show a significantly reduced flight-to-light behaviour compared with populations of the same species from pristine dark-sky habitats. Using a common garden setting, we reared moths from 10 different populations from early-instar larvae and experimentally compared their flight-to-light behaviour under standardized conditions. Moths from urban populations had a significant reduction in the flight-to-light behaviour compared with pristine populations. The reduced attraction to light sources of 'city moths' may directly increase these individuals' survival and reproduction. We anticipate that it comes with a reduced mobility, which negatively affects foraging as well as colonization ability. As nocturnal insects are of eminent significance as pollinators and the primary food source of many vertebrates, an evolutionary change of the flight-to-light behaviour thereby potentially cascades across species interaction networks. © 2016 The Author(s).

Onset of Oviposition Triggers Abrupt Reduction in Migratory Flight Behavior and Flight Muscle in the Female Beet Webworm, Loxostege sticticalis

PubMed Central

Cheng, Yunxia; Luo, Lizhi; Sappington, Thomas W.; Jiang, Xingfu; Zhang, Lei; Frolov, Andrei N.

2016-01-01

Flight and reproduction are usually considered as two life history traits that compete for resources in a migratory insect. The beet webworm, Loxostege sticticalis L., manages the costs of migratory flight and reproduction through a trade-off in timing of these two life history traits, where migratory behavior occurs during the preoviposition period. To gain insight into how migratory flight and reproduction are coordinated in the female beet webworm, we conducted experiments beginning at the end of the preoviposition period. We used flight mills to test whether flight performance and supportive flight musculature and fuel are affected by the number of eggs oviposited, or by the age of mated and unmated females after onset of oviposition by the former. The results showed that flight distance, flight velocity, flight duration, and flight muscle mass decreased abruptly at the onset of oviposition, compared to that of virgin females of the same age which did not change over the next 7 d. These results indicate that onset of oviposition triggers a decrease in flight performance and capacity in female beet webworms, as a way of actively managing reallocation of resources away from migratory flight and into egg production. In addition to the abrupt switch, there was a gradual, linear decline in flight performance, flight muscle mass, and flight fuel relative to the number of eggs oviposited. The histolysis of flight muscle and decrease of triglyceride content indicate a progressive degradation in the ability of adults to perform additional migratory flights after onset of oviposition. Although the results show that substantial, albeit reduced, long-duration flights remain possible after oviposition begins, additional long-distance migratory flights probably are not launched after the initiation of oviposition. PMID:27893835

Onset of Oviposition Triggers Abrupt Reduction in Migratory Flight Behavior and Flight Muscle in the Female Beet Webworm, Loxostege sticticalis.

PubMed

Cheng, Yunxia; Luo, Lizhi; Sappington, Thomas W; Jiang, Xingfu; Zhang, Lei; Frolov, Andrei N

2016-01-01

Flight and reproduction are usually considered as two life history traits that compete for resources in a migratory insect. The beet webworm, Loxostege sticticalis L., manages the costs of migratory flight and reproduction through a trade-off in timing of these two life history traits, where migratory behavior occurs during the preoviposition period. To gain insight into how migratory flight and reproduction are coordinated in the female beet webworm, we conducted experiments beginning at the end of the preoviposition period. We used flight mills to test whether flight performance and supportive flight musculature and fuel are affected by the number of eggs oviposited, or by the age of mated and unmated females after onset of oviposition by the former. The results showed that flight distance, flight velocity, flight duration, and flight muscle mass decreased abruptly at the onset of oviposition, compared to that of virgin females of the same age which did not change over the next 7 d. These results indicate that onset of oviposition triggers a decrease in flight performance and capacity in female beet webworms, as a way of actively managing reallocation of resources away from migratory flight and into egg production. In addition to the abrupt switch, there was a gradual, linear decline in flight performance, flight muscle mass, and flight fuel relative to the number of eggs oviposited. The histolysis of flight muscle and decrease of triglyceride content indicate a progressive degradation in the ability of adults to perform additional migratory flights after onset of oviposition. Although the results show that substantial, albeit reduced, long-duration flights remain possible after oviposition begins, additional long-distance migratory flights probably are not launched after the initiation of oviposition.

First-principles equation-of-state table of silicon and its effects on high-energy-density plasma simulations

NASA Astrophysics Data System (ADS)

Hu, S. X.; Gao, R.; Ding, Y.; Collins, L. A.; Kress, J. D.

2017-04-01

Using density-functional theory-based molecular-dynamics simulations, we have investigated the equation of state for silicon in a wide range of plasma density and temperature conditions of ρ =0.001 -500 g /c m3 and T =2000 -108K . With these calculations, we have established a first-principles equation-of-state (FPEOS) table of silicon for high-energy-density (HED) plasma simulations. When compared with the widely used SESAME-EOS model (Table 3810), we find that the FPEOS-predicted Hugoniot is ˜20% softer; for off-Hugoniot plasma conditions, the pressure and internal energy in FPEOS are lower than those of SESAME EOS for temperatures above T ≈ 1-10 eV (depending on density), while the former becomes higher in the low-T regime. The pressure difference between FPEOS and SESAME 3810 can reach to ˜50%, especially in the warm-dense-matter regime. Implementing the FPEOS table of silicon into our hydrocodes, we have studied its effects on Si-target implosions. When compared with the one-dimensional radiation-hydrodynamics simulation using the SESAME 3810 EOS model, the FPEOS simulation showed that (1) the shock speed in silicon is ˜10% slower; (2) the peak density of an in-flight Si shell during implosion is ˜20% higher than the SESAME 3810 simulation; (3) the maximum density reached in the FPEOS simulation is ˜40% higher at the peak compression; and (4) the final areal density and neutron yield are, respectively, ˜30% and ˜70% higher predicted by FPEOS versus the traditional simulation using SESAME 3810. All of these features can be attributed to the larger compressibility of silicon predicted by FPEOS. These results indicate that an accurate EOS table, like the FPEOS presented here, could be essential for the precise design of targets for HED experiments.

First-principles equation-of-state table of silicon and its effects on high-energy-density plasma simulations

DOE PAGES

Hu, S. X.; Gao, R.; Ding, Y.; ...

2017-04-21

Using density-functional theory–based molecular-dynamics simulations, we have investigated the equation of state for silicon in a wide range of plasma density and temperature conditions of ρ=0.001–500g/cm 3 and T=2000–10 8K. With these calculations, we have established a first-principles equation-of-state (FPEOS) table of silicon for high-energy-density (HED) plasma simulations. When compared with the widely used SESAME-EOS model (Table 3810), we find that the FPEOS-predicted Hugoniot is ~20% softer; for off-Hugoniot plasma conditions, the pressure and internal energy in FPEOS are lower than those of SESAME EOS for temperatures above T ≈ 1–10 eV (depending on density), while the former becomes highermore » in the low- T regime. The pressure difference between FPEOS and SESAME 3810 can reach to ~50%, especially in the warm-dense-matter regime. Implementing the FPEOS table of silicon into our hydrocodes, we have studied its effects on Si-target implosions. When compared with the one-dimensional radiation-hydrodynamics simulation using the SESAME 3810 EOS model, the FPEOS simulation showed that (1) the shock speed in silicon is ~10% slower; (2) the peak density of an in-flight Si shell during implosion is ~20% higher than the SESAME 3810 simulation; (3) the maximum density reached in the FPEOS simulation is ~40% higher at the peak compression; and (4) the final areal density and neutron yield are, respectively, ~30% and ~70% higher predicted by FPEOS versus the traditional simulation using SESAME 3810. All of these features can be attributed to the larger compressibility of silicon predicted by FPEOS. Furthermore, these results indicate that an accurate EOS table, like the FPEOS presented here, could be essential for the precise design of targets for HED experiments.« less

First-principles equation-of-state table of silicon and its effects on high-energy-density plasma simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, S. X.; Gao, R.; Ding, Y.

Using density-functional theory–based molecular-dynamics simulations, we have investigated the equation of state for silicon in a wide range of plasma density and temperature conditions of ρ=0.001–500g/cm 3 and T=2000–10 8K. With these calculations, we have established a first-principles equation-of-state (FPEOS) table of silicon for high-energy-density (HED) plasma simulations. When compared with the widely used SESAME-EOS model (Table 3810), we find that the FPEOS-predicted Hugoniot is ~20% softer; for off-Hugoniot plasma conditions, the pressure and internal energy in FPEOS are lower than those of SESAME EOS for temperatures above T ≈ 1–10 eV (depending on density), while the former becomes highermore » in the low- T regime. The pressure difference between FPEOS and SESAME 3810 can reach to ~50%, especially in the warm-dense-matter regime. Implementing the FPEOS table of silicon into our hydrocodes, we have studied its effects on Si-target implosions. When compared with the one-dimensional radiation-hydrodynamics simulation using the SESAME 3810 EOS model, the FPEOS simulation showed that (1) the shock speed in silicon is ~10% slower; (2) the peak density of an in-flight Si shell during implosion is ~20% higher than the SESAME 3810 simulation; (3) the maximum density reached in the FPEOS simulation is ~40% higher at the peak compression; and (4) the final areal density and neutron yield are, respectively, ~30% and ~70% higher predicted by FPEOS versus the traditional simulation using SESAME 3810. All of these features can be attributed to the larger compressibility of silicon predicted by FPEOS. Furthermore, these results indicate that an accurate EOS table, like the FPEOS presented here, could be essential for the precise design of targets for HED experiments.« less

Effects of lifting tempo on one repetition maximum and hormonal responses to a bench press protocol.

PubMed

Headley, Samuel A; Henry, Kelley; Nindl, Bradley C; Thompson, Brian A; Kraemer, William J; Jones, Margaret T

2011-02-01

This study was carried out in 2 parts: part 1 was designed to measure the 1 repetition maximum (1RM) bench press with 2 different moderate-velocity tempos (2/0/2) vs. (2/0/4) in male lifters while part 2 compared the hormonal responses at the same tempos as described in part 1. In both parts 1 and 2, the 1RMs (lbs) were higher on the 2/0/2 tempo than on the 2/0/4 tempo. The change in plasma volume (PV) was greater after the 2/0/4 tempo (-5.7 ± 1.7% vs. 0.96 ± 1.2%, p < 0.05). All blood parameters were significantly (p < 0.05) higher post-exercise compared with baseline. With PV corrected, insulin-like growth factor 1 (IGF-1) (ng·mL⁻¹) was higher with the 2/0/2 tempo only (pre-exercise: 277.4 ± 21.8, post-exercise: 308.1 ± 22.9; 2/0/4 tempo pre-exercise: 277.2 ± 17.6, post-exercise: 284.8 ± 21.2). In conclusion, heavier loads can be lifted and more total work can be performed using a (2/0/2) tempo compared with a slower (2/0/4) tempo, but with the exception of IGF-1, the hormonal responses are similar. Individuals may get the same metabolic responses to training by using different tempos, but they will need to use less weight at a slower tempo.

Artificial evolution of the morphology and kinematics in a flapping-wing mini-UAV.

PubMed

de Margerie, E; Mouret, J B; Doncieux, S; Meyer, J-A

2007-12-01

Birds demonstrate that flapping-wing flight (FWF) is a versatile flight mode, compatible with hovering, forward flight and gliding to save energy. This extended flight domain would be especially useful on mini-UAVs. However, design is challenging because aerodynamic efficiency is conditioned by complex movements of the wings, and because many interactions exist between morphological (wing area, aspect ratio) and kinematic parameters (flapping frequency, stroke amplitude, wing unfolding). Here we used artificial evolution to optimize these morpho-kinematic features on a simulated 1 kg UAV, equipped with wings articulated at the shoulder and wrist. Flight tests were conducted in a dedicated steady aerodynamics simulator. Parameters generating horizontal flight for minimal mechanical power were retained. Results showed that flight at medium speed (10-12 m s(-1)) can be obtained for reasonable mechanical power (20 W kg(-1)), while flight at higher speed (16-20 m s(-1)) implied increased power (30-50 W kg(-1)). Flight at low speed (6-8 m s(-1)) necessitated unrealistic power levels (70-500 W kg(-1)), probably because our simulator neglected unsteady aerodynamics. The underlying adaptation of morphology and kinematics to varying flight speed were compared to available biological data on the flight of birds.

Comparative Transcriptome Analyses Uncover Key Candidate Genes Mediating Flight Capacity in Bactrocera dorsalis (Hendel) and Bactrocera correcta (Bezzi) (Diptera: Tephritidae).

PubMed

Guo, Shaokun; Zhao, Zihua; Liu, Lijun; Li, Zhihong; Shen, Jie

2018-01-30

Flight capacity is important for invasive pests during entry, establishment and spreading. Both Bactrocera dorsalis Hendel and Bactrocera correcta Bezzi are invasive fruit flies but their flight capacities differ. Here, a tethered flight mill test demonstrated that B. dorsalis exhibits a greater flight capacity than B. correcta . RNA-Seq was used to determine the transcriptomic differences associated with the flight capacity of two Bactrocera species. Transcriptome data showed that 6392 unigenes were differentially expressed between the two species in the larval stage, whereas in the adult stage, 4104 differentially expressed genes (DEGs) were identified in females, and 3445 DEGs were observed in males. The flight capacity appeared to be correlated with changes in the transcriptional levels of genes involved in wing formation, flight muscle structure, energy metabolism, and hormonal control. Using RNA interference (RNAi) to verify the function of one DEG, the epidermal growth factor receptor ( EGFR ), we confirmed the role of this gene in regulating wing development, and thereby flight capacity, in both species. This work reveals the flight mechanism of fruit flies and provides insight into fundamental transcriptomics for further studies on the flight performance of insects.

Comparative Transcriptome Analyses Uncover Key Candidate Genes Mediating Flight Capacity in Bactrocera dorsalis (Hendel) and Bactrocera correcta (Bezzi) (Diptera: Tephritidae)

PubMed Central

Zhao, Zihua; Liu, Lijun; Li, Zhihong; Shen, Jie

2018-01-01

Flight capacity is important for invasive pests during entry, establishment and spreading. Both Bactrocera dorsalis Hendel and Bactrocera correcta Bezzi are invasive fruit flies but their flight capacities differ. Here, a tethered flight mill test demonstrated that B. dorsalis exhibits a greater flight capacity than B. correcta. RNA-Seq was used to determine the transcriptomic differences associated with the flight capacity of two Bactrocera species. Transcriptome data showed that 6392 unigenes were differentially expressed between the two species in the larval stage, whereas in the adult stage, 4104 differentially expressed genes (DEGs) were identified in females, and 3445 DEGs were observed in males. The flight capacity appeared to be correlated with changes in the transcriptional levels of genes involved in wing formation, flight muscle structure, energy metabolism, and hormonal control. Using RNA interference (RNAi) to verify the function of one DEG, the epidermal growth factor receptor (EGFR), we confirmed the role of this gene in regulating wing development, and thereby flight capacity, in both species. This work reveals the flight mechanism of fruit flies and provides insight into fundamental transcriptomics for further studies on the flight performance of insects. PMID:29385681

Aviator's Fluid Balance During Military Flight.

PubMed

Levkovsky, Anna; Abot-Barkan, Sivan; Chapnik, Leah; Doron, Omer; Levy, Yuval; Heled, Yuval; Gordon, Barak

2018-02-01

A loss of 1% or more of bodyweight due to dehydration has a negative effect on cognitive performance, which could critically affect flight safety. There is no mention in the literature concerning the amounts of military pilots' fluid loss during flight. The aim of this study was to quantify fluid loss of pilots during military flight. There were 48 aviators (mean age 23.9) from the Israeli Air Force who participated in the study, which included 104 training flights in various flight platforms. Bodyweight, urine specific gravity, and environmental heat strain were measured before and after each flight. Fluid loss was calculated as the weight differences before and after the flight. We used a univariate and one-way ANOVA to analyze the effect of different variables on the fluid loss. The mean fluid loss rate was 462 ml · h-1. The results varied among different aircraft platforms and depended on flight duration. Blackhawk pilots lost the highest amount of fluids per flight, albeit had longer flights (mean 108 min compared to 35.5 in fighter jets). Jet fighter pilots had the highest rate of fluid loss per hour of flight (up to 692 ml, extrapolated). Overall, at 11 flights (11%) aircrew completed their flight with a meaningful fluid loss. We conclude that military flights may be associated with significant amount of fluid loss among aircrew.Levkovsky A, Abot-Barkan S, Chapnik L, Doron O, Levy Y, Heled Y, Gordon B. Aviator's fluid balance during military flight. Aerosp Med Hum Perform. 2018; 89(2):9498.

75 FR 21044 - Notice of Centennial Challenges 2011 CAFE Green Flight Challenge

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-22

... is a prize competition designed to bring about the development of new aviation technologies that can... Comparative Aircraft Flight Efficiency (CAFE) Foundation. NASA is providing the prize purse. DATES: 2011 CAFE...

Trends in software reliability for digital flight control

NASA Technical Reports Server (NTRS)

Hecht, H.; Hecht, M.

1983-01-01

Software error data of major recent Digital Flight Control Systems Development Programs. The report summarizes the data, compare these data with similar data from previous surveys and identifies trends and disciplines to improve software reliability.

Studies of Vestibular Neurons in Normal, Hyper- and Hypogravity

NASA Technical Reports Server (NTRS)

Correia, Manning J.

1996-01-01

During the past year, pre-, in- and postflight studies were conducted in association with the Axon project for Bion 10 (Cosmos 2229). Recordings were made during pre- and postflight studies, from 118 horizontal semicircular canal afferents and 27 vestibular nucleus neurons in 7 rhesus monkeys; 137 pulse rotation protocols alone were executed (548 acceleration and deceleration responses were curve fit). Usable data was obtained from 127 horizontal afferents concerning their spontaneous discharge. Curve fits and analysis was made of sinusoidal and sum of sinusoidal responses from 42 and 35 horizontal afferents, respectively. Also recordings were made from neurons inflight from the two flight animals. The mean spontaneous rate varied from 128 spikes/sec. during preflight to 92 spikes/sec during postflight (day 5) - a change of 28%. In direct contrast to the results of Cosmos 2044, the best fitted neural adaptation operator (k) and the gain of the pulse response were decreased during post flight when compared to preflight. Surprisingly, the best fitted gain and k values for the sum of sines were slightly elevated during post flight tests. The gain and phase of single sine responses were compared for pre- and post flight tests and compared to a larger population of afferents. In contrast to Cosmos 2044 results where on the first day of post flight testing the gains of the best fitted sine response were skewed toward the higher values of the Miles and Braitman distribution, the gain of the best fitted sine responses during the first day of post flight testing (day 2) during Cosmos 2229 were exactly on the mode of the Miles and Braitman distribution. Thus, at least for the periodic stimuli, (pulses and sine waves) we found no change in gain and neural adaptation during post flight testing following Cosmos 2229. This conclusion is different from the one derived following the Cosmos 2044 flight. Cosmos flight 2229 differed from Cosmos flight 2044 in several significant ways: For example, during preflight, (1) The animals preflight training was different (less well trained on the gaze task) and (2) the animals were exposed to more experimental manipulations (surgical and rotational). Inflight, (1) the animals were required to make a pointing gesture (motor response) in association with eye movements to obtain reward, (2) the inflight diet was different (more balanced), (3) the feeder for one of the animals clogged following 9 days of flight resulting in evident dehydration and probably less head motion exposure in that monkey and (4) there was limited video taping of the monkeys in space. During postflight, (1) we were unable to test the flight animals until 26 hours postflight as compared to 14.5 hours during Cosmos 2044, (2) the animals received significantly more exposure to motion stimuli during postflight testing than during Cosmos 2044. These differences in the vestibular environment will require analysis of several parameters other than just neural and eye movement responses. For example, computer programs will have to be written and used to recover and quantify the number of head movements made by each animal during flight. This activity is critical to the production of neural adaptation and increased gain.

Green Flight Challenge

NASA Image and Video Library

2011-09-27

Pipistrel-USA Pilots Robin Reid, left, and David Morss, talk on their cell phones shortly after participating in the miles per gallon (MPG) flight in their Taurus G4 aircraft during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Tuesday, Sept. 27, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

A comparison of computer-generated lift and drag polars for a Wortmann airfoil to flight and wind tunnel results

NASA Technical Reports Server (NTRS)

Bowers, A. H.; Sandlin, D. R.

1984-01-01

Computations of drag polars for a low-speed Wortmann sailplane airfoil are compared to both wind tunnel and flight results. Excellent correlation is shown to exist between computations and flight results except when separated flow regimes were encountered. Wind tunnel transition locations are shown to agree with computed predictions. Smoothness of the input coordinates to the PROFILE airfoil analysis computer program was found to be essential to obtain accurate comparisons of drag polars or transition location to either the flight or wind tunnel results.

In-flight acoustic test results for the SR-2 and SR-3 advanced-design propellers

NASA Technical Reports Server (NTRS)

Lasagna, P. L.; Mackall, K. G.; Cohn, R. B.

1983-01-01

Several advanced-design propellers, previously tested in the wind tunnel at the Lewis Research Center, have been tested in flight at the Dryden Flight Research Facility. The flight-test propellers were mounted on a pylon on the top of the fuselage of a JetStar airplane. Acoustic data for the advanced-design SR-2 and SR-3 propellers at Mach numbers to 0.8 and helical-tip Mach numbers to 1.15 are presented; maximum blade-passage frequency sound-pressure levels are also compared.

The energy expenditure of helicopter pilots.

PubMed

Thornton, R; Brown, G A; Higenbottam, C

1984-08-01

The energy expenditure of Army Air Corps and Royal Air Force pilots has been measured during flight in Gazelle and Puma helicopters respectively. Heart rates were also recorded. The results were compared with resting values obtained in the crewroom before flight, and confirmed the findings of other authors that the energy cost of flying helicopters in level flight is about 50% higher than that of sitting at rest.

Analysis of general aviation accidents during operations under instrument flight rules

NASA Technical Reports Server (NTRS)

Bennett, C. T.; Schwirzke, Martin; Harm, C.

1990-01-01

A report is presented to describe some of the errors that pilots make during flight under IFR. The data indicate that there is less risk during the approach and landing phase of IFR flights, as compared to VFR operations. Single-pilot IFR accident rates continue to be higher than two-pilot IFR incident rates, reflecting the high work load of IFR operations.

Green Flight Challenge

NASA Image and Video Library

2011-09-25

The PhoEnix aircraft takes off during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Monday, Sept. 26, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-28

A hot air balloon passes over the campus of the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Thursday, Sept. 29, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-27

The campus of the 2011 Green Flight Challenge, sponsored by Google, is seen in this aerial view at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Wednesday, Sept. 28, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-25

The Pipistrel-USA, Taurus G4 aircraft takes off during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Monday, Sept. 26, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-28

A hot air balloons pass over the campus of the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Thursday, Sept. 29, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

Green Flight Challenge

NASA Image and Video Library

2011-09-25

The e-Genius aircraft takes off during the 2011 Green Flight Challenge, sponsored by Google, at the Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. on Monday, Sept. 26, 2011. NASA and the Comparative Aircraft Flight Efficiency (CAFE) Foundation are having the challenge with the goal to advance technologies in fuel efficiency and reduced emissions with cleaner renewable fuels and electric aircraft. Photo Credit: (NASA/Bill Ingalls)

KC-135 winglet flight results

NASA Technical Reports Server (NTRS)

Montoya, L. C.

1981-01-01

Three KC-135 winglet configurations were flight tested for cant/incidence angles of 15 deg/-4 deg, 15 deg/-2 deg, and 0 deg/-4 deg, as well as the basic wing. The flight results for the 15 deg/-4 deg and basic wing configurations confirm the wind tunnel predicted 7% incremental decrease in total drag at cruise conditions. The 15 deg/-4 configuration flight measured wing and winglet pressure distributions, loads, stability and control, flutter, and buffet also correlate well with predicted values. The only unexpected flight results as compared with analytical predictions is a flutter speed decrease for the 0 deg/-4 deg configuration. The 15 deg/-2 deg configuration results show essentially the same incremental drag reduction as the 15 deg/-4 deg configuration; however, the flight loads are approximately 30% higher for the 15 deg/-2 deg configuration. The drag data for the 0 deg/-4 deg configuration show only a flight drag reduction.

Lateral and longitudinal aerodynamic stability and control parameters of the basic vortex flap research aircraft as determined from flight test data

NASA Technical Reports Server (NTRS)

Suit, W. T.; Batterson, J. G.

1986-01-01

The aerodynamics of the basic F-106B were determined at selected points in the flight envelope. The test aircraft and flight procedures were presented. Aircraft instrumentation and the data system were discussed. The parameter extraction procedure was presented along with a discussion of the test flight results. The results were used to predict the aircraft motions for maneuvers that were not used to determine the vehicle aerodynamics. The control inputs used to maneuver the aircraft to get data for the determination of the aerodynamic parameters were discussed in the flight test procedures. The results from the current flight tests were compared with the results from wind tunnel test of the basic F-106B.

Thrust imbalance of solid rocket motor pairs on Space Shuttle flights

NASA Technical Reports Server (NTRS)

Foster, W. A., Jr.; Shu, P. H.; Sforzini, R. H.

1986-01-01

This analysis extends the investigation presented at the 17th Joint Propulsion Conference in 1981 to include fifteen sets of Space Shuttle flight data. The previous report dealt only with static test data and the first flight pair. The objective is to compare the authors' previous theoretical analysis of thrust imbalance with actual Space Shuttle performance. The theoretical prediction method, which involves a Monte Carlo technique, is reviewed briefly as are salient features of the flight instrumentation system and the statistical analysis. A scheme for smoothing flight data is discussed. The effects of changes in design parameters are discussed with special emphasis on the filament wound motor case being developed to replace the steel case. Good agreement between the predictions and the flight data is demonstrated.

Midcourse Guidance Study for Tactical Guided Weapons. Volume I. Survey and Analysis

DTIC Science & Technology

1976-08-01

relatively moderate when compared to air intercept guidance requirements.) The alignment phase involved the comparison of gyrocom- passing (using... phase of flight for discrete updates. The AFBGW aero and guidance configuration is derived from current Air Force glide weapon concepts. The AFBGW... comparable midcourse flight phase . Harpoon and Standard Arm represent performance levels similar to the AFBGW requirements, but differences in

Cockpit data management

NASA Technical Reports Server (NTRS)

Groce, J. L.; Boucek, G. P.

1988-01-01

This study is a continuation of an FAA effort to alleviate the growing problems of assimilating and managing the flow of data and flight related information in the air transport flight deck. The nature and extent of known pilot interface problems arising from new NAS data management programs were determined by a comparative timeline analysis of crew tasking requirements. A baseline of crew tasking requirements was established for conventional and advanced flight decks operating in the current NAS environment and then compared to the requirements for operation in a future NAS environment emphasizing Mode-S data link and TCAS. Results showed that a CDU-based pilot interface for Mode-S data link substantially increased crew visual activity as compared to the baseline. It was concluded that alternative means of crew interface should be available during high visual workload phases of flight. Results for TCAS implementation showed substantial visual and motor tasking increases, and that there was little available time between crew tasks during a TCAS encounter. It was concluded that additional research should be undertaken to address issues of ATC coordination and the relative benefit of high workload TCAS features.

Altered Innate and Lymphocytic Immune Responses in Mouse Splenocytes Post-Flight

NASA Technical Reports Server (NTRS)

Hwang, ShenAn; Crucian, Brian E.; Sams, Clarence F.; Actor, Jeffrey K.

2011-01-01

Space flight is known to affect immune responses of astronauts and animals, decreasing lymphocytic responses to mitogenic stimuli, delayed typed hypersensitivity reactions, and T-cell activation. Despite changes in immune suppression, there are no reports of consistent adverse clinical events post flight. To further investigate the spectrum of affected immune responses, murine splenocytes were stimulated immediately post-shuttle flight (14 days on STS-135) with T-cell stimulators or toll-like receptor agonists. Comparisons were made to ground control splenocytes from age-matched mice. Cell phenotypes were assessed, as well as activation markers and associated cytokine production. The CD4+ population decreased with no concurrent decrease in CD8+ cells from shuttle mice post flight compared to ground controls. Regarding antigen presenting cell populations, the number of CD11c+ cells were slightly elevated post flight, compared to ground controls, with increased MHC Class I expression (I-A(sup b)) and no change in Class II expression (H-2K(sup b)). CD86+ populations were also significantly diminished. However, the decreased markers did not correlate with activity. Stimulation of splenocytes post flight showed significant increase in bead uptake, increased Class I expression, increased TNF-alpha and IL-6 production in response to TLR-2 (zymosan) and TLR-4 (LPS) agonists. While most activated (ConA or anti-CD3/anti-CD28) CD4+ cells showed markedly diminished responses (reduced IL-2 production), non-specific T cell responses to superantigen (SEA/SEB) increased post flight as determined by expression of early activation markers. Production of additional cytokines was also dysregulated postflight. Overall, persistent immune changes during space flight could represent unique clinical risks for exploration class missions. The consequences of pathogenic encounter remain an important concern that should be addressed.

Dietary mercury exposure causes decreased escape takeoff flight performance and increased molt rate in European starlings (Sturnus vulgaris).

PubMed

Carlson, Jenna R; Cristol, Daniel; Swaddle, John P

2014-10-01

Mercury is a widespread and persistent environmental contaminant that occurs in aquatic and terrestrial habitats. Recently, songbirds that forage from primarily terrestrial sources have shown evidence of bioaccumulation of mercury, but little research has assessed the effects of mercury on their health and fitness. There are many indications that mercury negatively affects neurological functioning, bioenergetics, and behavior through a variety of mechanisms and in a wide array of avian taxa. Effective flight is crucial to avian fitness and feather molt is an energetically expensive life history trait. Therefore, we investigated whether mercury exposure influenced flight performance and molt in a common songbird, the European starling (Sturnus vulgaris). Specifically, we dosed the diet of captive starlings with methylmercury cysteine at 0.0, 0.75, or 1.5 μg/g wet weight and recorded changes in flight performance after 1 year of dietary mercury exposure. We also recorded the annual molt of wing feathers. We found that individuals dosed with mercury exhibited decreased escape takeoff flight performance compared with controls and blood mercury was also correlated with an increased rate of molt, which can reduce flight performance and thermoregulatory ability. This study reveals two novel endpoints, flight performance and molt, that may be affected by dietary mercury exposure. These findings suggest a potential impact on wild songbirds exposed to mercury levels comparable to the high dosage levels in the present study. Any decrease in flight efficiency could reduce fitness due to a direct impact on survival during predation events or by decreased efficiency in other critical activities (such as foraging or migration) that require efficient flight.

Adaptive control of a millimeter-scale flapping-wing robot.

PubMed

Chirarattananon, Pakpong; Ma, Kevin Y; Wood, Robert J

2014-06-01

Challenges for the controlled flight of a robotic insect are due to the inherent instability of the system, complex fluid-structure interactions, and the general lack of a complete system model. In this paper, we propose theoretical models of the system based on the limited information available from previous work and a comprehensive flight controller. The modular flight controller is derived from Lyapunov function candidates with proven stability over a large region of attraction. Moreover, it comprises adaptive components that are capable of coping with uncertainties in the system that arise from manufacturing imperfections. We have demonstrated that the proposed methods enable the robot to achieve sustained hovering flights with relatively small errors compared to a non-adaptive approach. Simple lateral maneuvers and vertical takeoff and landing flights are also shown to illustrate the fidelity of the flight controller. The analysis suggests that the adaptive scheme is crucial in order to achieve millimeter-scale precision in flight control as observed in natural insect flight.

The Route Analysis Based On Flight Plan

NASA Astrophysics Data System (ADS)

Feriyanto, Nur; Saleh, Chairul; Fauzi, Achmad; Rachman Dzakiyullah, Nur; Riza Iwaputra, Kahfi

2016-02-01

Economic development effects use of air transportation since the business process in every aspect was increased. Many people these days was prefer using airplane because it can save time and money. This situation also effects flight routes, many airlines offer new routes to deal with competition. Managing flight routes is one of the problems that must be faced in order to find the efficient and effective routes. This paper investigates the best routes based on flight performance by determining the amount of block fuel for the Jakarta-Denpasar flight route. Moreover, in this work compares a two kinds of aircraft and tracks by calculating flight distance, flight time and block fuel. The result shows Jakarta-Denpasar in the Track II has effective and efficient block fuel that can be performed by Airbus 320-200 aircraft. This study can contribute to practice in making an effective decision, especially helping executive management of company due to selecting appropriate aircraft and the track in the flight plan based on the block fuel consumption for business operation.

[Comparative efficacy of different regimens of locomotor training in long-term space flights by the data of biomechanical and electromyographic parametrs of walking].

PubMed

Shpakov, A V; Voronov, A V; Fomina, E V; Lysova, N Iu; Chernova, M V; Kozlovskaia, I B

2013-01-01

Biomechanical and electromyographic characteristics of locomotion were investigated before and after space flight on the 3rd, 7th and 10th day after landing in 18 cosmonauts--crewmembers of long-term ISS space flights. It was shown that microgravity causes the development of significant changes in biomechanical and electromyographic characteristics of walking. Decrease of the angular displacement amplitude in leg joints, reduction of the length of the double step, increase of the electromyographic cost of locomotion were recorded after flight. It was also shown that interval locomotor physical training in long-term space flights in the regimen of alternation running and walking prevents physiological cost of locomotor movements increase after space flight and provides more effective maintenance of the neuromuscular system functions after flight. After flight smaller changes of biomechanical and electromyographic characteristics of walking were observed in cosmonauts who used locomotor training in interval regimen.

Collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation

NASA Astrophysics Data System (ADS)

Yang, Shangwen; Guo, Baohua; Xiao, Xuefei; Gao, Haichao

2018-01-01

To allocate the en-routes and slots to the flights with collaborative decision making, a collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation was proposed. Evaluation indexes include flight delay costs, delay time and the number of turning points. Analytic hierarchy process is applied to determining index weights. Remark set for current two flights not yet obtained the en-route and slot in flight schedule is established. Then, fuzzy comprehensive evaluation is performed, and the en-route and slot for the current two flights are determined. Continue selecting the flight not yet obtained an en-route and a slot in flight schedule. Perform fuzzy comprehensive evaluation until all flights have obtained the en-routes and slots. MatlabR2007b was applied to numerical test based on the simulated data of a civil en-route. Test results show that, compared with the traditional strategy of first come first service, the algorithm gains better effect. The effectiveness of the algorithm was verified.

High pressure study on molecular mobility of leucrose

NASA Astrophysics Data System (ADS)

Kaminski, K.; Kaminska, E.; Hensel-Bielowka, S.; Pawlus, S.; Paluch, M.; Ziolo, J.

2008-08-01

Broadband dielectric measurements on leucrose were performed under ambient and high pressure. We showed that in this disaccharide, there are two secondary relaxation modes, a slower one sensitive to pressure and a faster one that is not. This finding clearly indicates that the faster secondary relaxation originates from the intramolecular motion. This conclusion contradicted previous interpretations of this mode observed for trehalose and maltitol, systems very closely related to leucrose. In addition, pressure sensitivity of the slower relaxation confirms our recent interpretation about the character of this process. Furthermore, we discovered that unlike the faster relaxation, the slower secondary relaxation is sensitive to the thermodynamic history of measurements. Finally, monitoring the changes in maximum loss of the slower secondary relaxation measured at the same pressure and temperature conditions for glasses obtained via different thermodynamic routes enabled us to draw a conclusion about the density of the formed glasses. Our observations may be helpful in establishing a new method of suppressing crystallization of amorphous drugs.