Piloted simulation of a ground-based time-control concept for air traffic control

NASA Technical Reports Server (NTRS)

Davis, Thomas J.; Green, Steven M.

1989-01-01

A concept for aiding air traffic controllers in efficiently spacing traffic and meeting scheduled arrival times at a metering fix was developed and tested in a real time simulation. The automation aid, referred to as the ground based 4-D descent advisor (DA), is based on accurate models of aircraft performance and weather conditions. The DA generates suggested clearances, including both top-of-descent-point and speed-profile data, for one or more aircraft in order to achieve specific time or distance separation objectives. The DA algorithm is used by the air traffic controller to resolve conflicts and issue advisories to arrival aircraft. A joint simulation was conducted using a piloted simulator and an advanced concept air traffic control simulation to study the acceptability and accuracy of the DA automation aid from both the pilot's and the air traffic controller's perspectives. The results of the piloted simulation are examined. In the piloted simulation, airline crews executed controller issued descent advisories along standard curved path arrival routes, and were able to achieve an arrival time precision of + or - 20 sec at the metering fix. An analysis of errors generated in turns resulted in further enhancements of the algorithm to improve the predictive accuracy. Evaluations by pilots indicate general support for the concept and provide specific recommendations for improvement.

Optimum Strategies for Selecting Descent Flight-Path Angles

NASA Technical Reports Server (NTRS)

Wu, Minghong G. (Inventor); Green, Steven M. (Inventor)

2016-01-01

An information processing system and method for adaptively selecting an aircraft descent flight path for an aircraft, are provided. The system receives flight adaptation parameters, including aircraft flight descent time period, aircraft flight descent airspace region, and aircraft flight descent flyability constraints. The system queries a plurality of flight data sources and retrieves flight information including any of winds and temperatures aloft data, airspace/navigation constraints, airspace traffic demand, and airspace arrival delay model. The system calculates a set of candidate descent profiles, each defined by at least one of a flight path angle and a descent rate, and each including an aggregated total fuel consumption value for the aircraft following a calculated trajectory, and a flyability constraints metric for the calculated trajectory. The system selects a best candidate descent profile having the least fuel consumption value while the fly ability constraints metric remains within aircraft flight descent flyability constraints.

Planning fuel-conservative descents with or without time constraints using a small programmable calculator: Algorithm development and flight test results

NASA Technical Reports Server (NTRS)

Knox, C. E.

1983-01-01

A simplified flight-management descent algorithm, programmed on a small programmable calculator, was developed and flight tested. It was designed to aid the pilot in planning and executing a fuel-conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The algorithm may also be used for planning fuel-conservative descents when time is not a consideration. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard temperature effects. The flight-management descent algorithm is described. The results of flight tests flown with a T-39A (Sabreliner) airplane are presented.

Description of the computations and pilot procedures for planning fuel-conservative descents with a small programmable calculator

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

Vicroy, D.D.; Knox, C.E.

A simplified flight management descent algorithm was developed and programmed on a small programmable calculator. It was designed to aid the pilot in planning and executing a fuel conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The algorithm may also be used for planning fuel conservative descents when time is not a consideration. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard temperature effects. The flight management descent algorithm and the vertical performance modelingmore » required for the DC-10 airplane is described.« less

A Terminal Area Analysis of Continuous Ascent Departure Fuel Use at Dallas/Fort Worth International Airport

NASA Technical Reports Server (NTRS)

Roach, Keenan; Robinson, John E., III

2010-01-01

Aircraft departing from the Dallas/Fort Worth International Airport (DFW) encounter vertical restrictions that prevent continuous ascent operations. The result of these restrictions are temporary level-offs at 10,000 feet. A combination of flow direction, specific Area Navigation (RNAV) route geometry, and arrival streams have been found to be the biggest factors in the duration and frequency of a temporary level-offs. In total, 20% of DFW departures are affected by these level-offs, which have an average duration of just over 100 seconds. The use of continuous descent approaches at DFW are shown to lessen the impact arrivals have on the departures and allow more continuous ascents. The fuel used in a continuous ascent and an ascent with a temporary level-off have been calculated using a fuel burn rate model created from a combination of actual aircraft track data, aircraft manufacturer flight operations manuals, and Eurocontrol's Base of Aircraft Data (BADA) simulation tool. This model represents the average aggregate burn rates for the current fleet mix at DFW. Continuous ascents would save approximately seven gallons of fuel out of 450 gallons used to climb to a cruise altitude of 31,000ft per departure.

A piloted simulator evaluation of a ground-based 4-D descent advisor algorithm

NASA Technical Reports Server (NTRS)

Davis, Thomas J.; Green, Steven M.; Erzberger, Heinz

1990-01-01

A ground-based, four dimensional (4D) descent-advisor algorithm is under development at NASA-Ames. The algorithm combines detailed aerodynamic, propulsive, and atmospheric models with an efficient numerical integration scheme to generate 4D descent advisories. The ability is investigated of the 4D descent advisor algorithm to provide adequate control of arrival time for aircraft not equipped with on-board 4D guidance systems. A piloted simulation was conducted to determine the precision with which the descent advisor could predict the 4D trajectories of typical straight-in descents flown by airline pilots under different wind conditions. The effects of errors in the estimation of wind and initial aircraft weight were also studied. A description of the descent advisor as well as the result of the simulation studies are presented.

2011 Mars Science Laboratory Launch Period Design

NASA Technical Reports Server (NTRS)

Abilleira, Fernando

2011-01-01

The Mars Science Laboratory mission, set to launch in the fall of 2011, has the primary objective of landing the most advanced rover to date to the surface of Mars to assess whether Mars ever was, or still is today, able to sustain carbon-based life. Arriving at Mars in August 2012, the Mars Science Laboratory will also demonstrate the ability to deliver large payloads to the surface of Mars, land more accurately (than previous missions) in a 20-km by 25-km ellipse, and traverse up to 20 km. Following guided entry and parachute deployment, the spacecraft will descend on a parachute and a Powered Descent Vehicle to safely land the rover on the surface of Mars. The launch/arrival strategy is driven by several key requirements, which include: launch vehicle capability, atmosphere-relative entry speed, communications coverage during Entry, Descent and Landing, latitude accessibility, and dust storm season avoidance. Notable among these requirements is maintaining a telecommunications link from atmospheric entry to landing plus one minute, via a Direct-To-Earth X-band link and via orbital assets using an UHF link, to ensure that any failure during Entry, Descent and Landing can be reconstructed in case of a mission anomaly. Due to concerns related to the lifetime of the relay orbiters, two additional launch/arrival strategies have been developed to improve Entry, Descent, and Landing communications. This paper discusses the final launch/arrival strategy selected prior to the launch period down-selection that is scheduled to occur in August 2011. It is also important to note that this paper is an update to Ref. 1 in that it includes two new Type 1 launch periods and drops the Type 2 launch period that is no longer considered.

Planning fuel-conservative descents with or without time constraints using a small programmable calculator: algorithm development and flight test results

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

Knox, C.E.

A simplified flight-management descent algorithm, programmed on a small programmable calculator, was developed and flight tested. It was designed to aid the pilot in planning and executing a fuel-conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The algorithm may also be used for planning fuel-conservative descents when time is not a consideration. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard temperature effects. The flight-management descent algorithm is described. The results of flight testsmore » flown with a T-39A (Sabreliner) airplane are presented.« less

Planning fuel-conservative descents in an airline environmental using a small programmable calculator: Algorithm development and flight test results

NASA Technical Reports Server (NTRS)

Knox, C. E.; Vicroy, D. D.; Simmon, D. A.

1985-01-01

A simple, airborne, flight-management descent algorithm was developed and programmed into a small programmable calculator. The algorithm may be operated in either a time mode or speed mode. The time mode was designed to aid the pilot in planning and executing a fuel-conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The speed model was designed for planning fuel-conservative descents when time is not a consideration. The descent path for both modes was calculated for a constant with considerations given for the descent Mach/airspeed schedule, gross weight, wind, wind gradient, and nonstandard temperature effects. Flight tests, using the algorithm on the programmable calculator, showed that the open-loop guidance could be useful to airline flight crews for planning and executing fuel-conservative descents.

Planning fuel-conservative descents in an airline environmental using a small programmable calculator: algorithm development and flight test results

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

Knox, C.E.; Vicroy, D.D.; Simmon, D.A.

A simple, airborne, flight-management descent algorithm was developed and programmed into a small programmable calculator. The algorithm may be operated in either a time mode or speed mode. The time mode was designed to aid the pilot in planning and executing a fuel-conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The speed model was designed for planning fuel-conservative descents when time is not a consideration. The descent path for both modes was calculated for a constant with considerations given for the descent Mach/airspeed schedule, gross weight, wind, wind gradient, andmore » nonstandard temperature effects. Flight tests, using the algorithm on the programmable calculator, showed that the open-loop guidance could be useful to airline flight crews for planning and executing fuel-conservative descents.« less

Descent Stage of Mars Science Laboratory During Assembly

NASA Technical Reports Server (NTRS)

2008-01-01

This image from early October 2008 shows personnel working on the descent stage of NASA's Mars Science Laboratory inside the Spacecraft Assembly Facility at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The descent stage will provide rocket-powered deceleration for a phase of the arrival at Mars after the phases using the heat shield and parachute. When it nears the surface, the descent stage will lower the rover on a bridle the rest of the way to the ground. The larger three of the orange spheres in the descent stage are fuel tanks. The smaller two are tanks for pressurant gas used for pushing the fuel to the rocket engines.

JPL, a division of the California Institute of Technology, manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington.

User's manual for a fuel-conservative descent planning algorithm implemented on a small programmable calculator

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

Vicroy, D.D.

A simplified flight management descent algorithm was developed and programmed on a small programmable calculator. It was designed to aid the pilot in planning and executing a fuel conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The algorithm may also be used for planning fuel conservative descents when time is not a consideration. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard temperature effects. An explanation and examples of how the algorithm is used,more » as well as a detailed flow chart and listing of the algorithm are contained.« less

Predictability of Top of Descent Location for Operational Idle-Thrust Descents

NASA Technical Reports Server (NTRS)

Stell, Laurel L.

2010-01-01

To enable arriving aircraft to fly optimized descents computed by the flight management system (FMS) in congested airspace, ground automation must accurately predict descent trajectories. To support development of the trajectory predictor and its uncertainty models, commercial flights executed idle-thrust descents at a specified descent speed, and the recorded data included the specified descent speed profile, aircraft weight, and the winds entered into the FMS as well as the radar data. The FMS computed the intended descent path assuming idle thrust after top of descent (TOD), and the controllers and pilots then endeavored to allow the FMS to fly the descent to the meter fix with minimal human intervention. The horizontal flight path, cruise and meter fix altitudes, and actual TOD location were extracted from the radar data. Using approximately 70 descents each in Boeing 757 and Airbus 319/320 aircraft, multiple regression estimated TOD location as a linear function of the available predictive factors. The cruise and meter fix altitudes, descent speed, and wind clearly improve goodness of fit. The aircraft weight improves fit for the Airbus descents but not for the B757. Except for a few statistical outliers, the residuals have absolute value less than 5 nmi. Thus, these predictive factors adequately explain the TOD location, which indicates the data do not include excessive noise.

Minimum-Cost Aircraft Descent Trajectories with a Constrained Altitude Profile

NASA Technical Reports Server (NTRS)

Wu, Minghong G.; Sadovsky, Alexander V.

2015-01-01

An analytical formula for solving the speed profile that accrues minimum cost during an aircraft descent with a constrained altitude profile is derived. The optimal speed profile first reaches a certain speed, called the minimum-cost speed, as quickly as possible using an appropriate extreme value of thrust. The speed profile then stays on the minimum-cost speed as long as possible, before switching to an extreme value of thrust for the rest of the descent. The formula is applied to an actual arrival route and its sensitivity to winds and airlines' business objectives is analyzed.

Mars Science Laboratory's Descent Stage

NASA Technical Reports Server (NTRS)

2008-01-01

This portion of NASA's Mars Science Laboratory, called the descent stage, does its main work during the final few minutes before touchdown on Mars.

The descent stage will provide rocket-powered deceleration for a phase of the arrival at Mars after the phases using the heat shield and parachute. When it nears the surface, the descent stage will lower the rover on a bridle the rest of the way to the ground.

The Mars Science Laboratory spacecraft is being assembled and tested for launch in 2011.

This image was taken at NASA's Jet Propulsion Laboratory, Pasadena, Calif., which manages the Mars Science Laboratory Mission for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology.

Descent advisor preliminary field test

NASA Technical Reports Server (NTRS)

Green, Steven M.; Vivona, Robert A.; Sanford, Beverly

1995-01-01

A field test of the Descent Advisor (DA) automation tool was conducted at the Denver Air Route Traffic Control Center in September 1994. DA is being developed to assist Center controllers in the efficient management and control of arrival traffic. DA generates advisories, based on trajectory predictions, to achieve accurate meter-fix arrival times in a fuel efficient manner while assisting the controller with the prediction and resolution of potential conflicts. The test objectives were to evaluate the accuracy of DA trajectory predictions for conventional- and flight-management-system-equipped jet transports, to identify significant sources of trajectory prediction error, and to investigate procedural and training issues (both air and ground) associated with DA operations. Various commercial aircraft (97 flights total) and a Boeing 737-100 research aircraft participated in the test. Preliminary results from the primary test set of 24 commercial flights indicate a mean DA arrival time prediction error of 2.4 sec late with a standard deviation of 13.1 sec. This paper describes the field test and presents preliminary results for the commercial flights.

Interval Management with Spacing to Parallel Dependent Runways (IMSPIDR) Experiment and Results

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Swieringa, Kurt A.; Capron, William R.

2012-01-01

An area in aviation operations that may offer an increase in efficiency is the use of continuous descent arrivals (CDA), especially during dependent parallel runway operations. However, variations in aircraft descent angle and speed can cause inaccuracies in estimated time of arrival calculations, requiring an increase in the size of the buffer between aircraft. This in turn reduces airport throughput and limits the use of CDAs during high-density operations, particularly to dependent parallel runways. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR) concept uses a trajectory-based spacing tool onboard the aircraft to achieve by the runway an air traffic control assigned spacing interval behind the previous aircraft. This paper describes the first ever experiment and results of this concept at NASA Langley. Pilots flew CDAs to the Dallas Fort-Worth airport using airspeed calculations from the spacing tool to achieve either a Required Time of Arrival (RTA) or Interval Management (IM) spacing interval at the runway threshold. Results indicate flight crews were able to land aircraft on the runway with a mean of 2 seconds and less than 4 seconds standard deviation of the air traffic control assigned time, even in the presence of forecast wind error and large time delay. Statistically significant differences in delivery precision and number of speed changes as a function of stream position were observed, however, there was no trend to the difference and the error did not increase during the operation. Two areas the flight crew indicated as not acceptable included the additional number of speed changes required during the wind shear event, and issuing an IM clearance via data link while at low altitude. A number of refinements and future spacing algorithm capabilities were also identified.

Development and test results of a flight management algorithm for fuel conservative descents in a time-based metered traffic environment

NASA Technical Reports Server (NTRS)

Knox, C. E.; Cannon, D. G.

1980-01-01

A simple flight management descent algorithm designed to improve the accuracy of delivering an airplane in a fuel-conservative manner to a metering fix at a time designated by air traffic control was developed and flight tested. This algorithm provides a three dimensional path with terminal area time constraints (four dimensional) for an airplane to make an idle thrust, clean configured (landing gear up, flaps zero, and speed brakes retracted) descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithm is described. The results of the flight tests flown with the Terminal Configured Vehicle airplane are presented.

A flight management algorithm and guidance for fuel-conservative descents in a time-based metered air traffic environment: Development and flight test results

NASA Technical Reports Server (NTRS)

Knox, C. E.

1984-01-01

A simple airborne flight management descent algorithm designed to define a flight profile subject to the constraints of using idle thrust, a clean airplane configuration (landing gear up, flaps zero, and speed brakes retracted), and fixed-time end conditions was developed and flight tested in the NASA TSRV B-737 research airplane. The research test flights, conducted in the Denver ARTCC automated time-based metering LFM/PD ATC environment, demonstrated that time guidance and control in the cockpit was acceptable to the pilots and ATC controllers and resulted in arrival of the airplane over the metering fix with standard deviations in airspeed error of 6.5 knots, in altitude error of 23.7 m (77.8 ft), and in arrival time accuracy of 12 sec. These accuracies indicated a good representation of airplane performance and wind modeling. Fuel savings will be obtained on a fleet-wide basis through a reduction of the time error dispersions at the metering fix and on a single-airplane basis by presenting the pilot with guidance for a fuel-efficient descent.

Strategies for Choosing Descent Flight-Path Angles for Small Jets

NASA Technical Reports Server (NTRS)

Wu, Minghong Gilbert; Green, Steven M.

2012-01-01

Three candidate strategies for choosing the descent flight path angle (FPA) for small jets are proposed, analyzed, and compared for fuel efficiency under arrival metering conditions. The strategies vary in operational complexity from a universally fixed FPA, or FPA function that varies with descent speed for improved fuel efficiency, to the minimum-fuel FPA computed for each flight based on winds, route, and speed profile. Methodologies for selecting the parameter for the first two strategies are described. The differences in fuel burn are analyzed over a year s worth of arrival traffic and atmospheric conditions recorded for the Dallas/Fort Worth (DFW) Airport during 2011. The results show that the universally fixed FPA strategy (same FPA for all flights, all year) burns on average 26 lbs more fuel per flight as compared to the minimum-fuel solution. This FPA is adapted to the arrival gate (direction of entry to the terminal) and various timespans (season, month and day) to improve fuel efficiency. Compared to a typical FPA of approximately 3 degrees the adapted FPAs vary significantly, up to 1.3 from one arrival gate to another or up to 1.4 from one day to another. Adapting the universally fixed FPA strategy to the arrival gate or to each day reduces the extra fuel burn relative to the minimum-fuel solution by 27% and 34%, respectively. The adaptations to gate and time combined shows up to 57% reduction of the extra fuel burn. The second strategy, an FPA function, contributes a 17% reduction in the 26 lbs of extra fuel burn over the universally fixed FPA strategy. Compared to the corresponding adaptations of the universally fixed FPA, adaptations of the FPA function reduce the extra fuel burn anywhere from 15-23% depending on the extent of adaptation. The combined effect of the FPA function strategy with both directional and temporal adaptation recovers 67% of the extra fuel relative to the minimum-fuel solution.

The Yearly Variation in Fall-Winter Arctic Winter Vortex Descent

NASA Technical Reports Server (NTRS)

Schoeberl, Mark R.; Newman, Paul A.

1999-01-01

Using the change in HALOE methane profiles from early September to late March, we have estimated the minimum amount of diabatic descent within the polar which takes place during Arctic winter. The year to year variations are a result in the year to year variations in stratospheric wave activity which (1) modify the temperature of the vortex and thus the cooling rate; (2) reduce the apparent descent by mixing high amounts of methane into the vortex. The peak descent amounts from HALOE methane vary from l0km -14km near the arrival altitude of 25 km. Using a diabatic trajectory calculation, we compare forward and backward trajectories over the course of the winter using UKMO assimilated stratospheric data. The forward calculation agrees fairly well with the observed descent. The backward calculation appears to be unable to produce the observed amount of descent, but this is only an apparent effect due to the density decrease in parcels with altitude. Finally we show the results for unmixed descent experiments - where the parcels are fixed in latitude and longitude and allowed to descend based on the local cooling rate. Unmixed descent is found to always exceed mixed descent, because when normal parcel motion is included, the path average cooling is always less than the cooling at a fixed polar point.

Flight Management System Execution of Idle-Thrust Descents in Operations

NASA Technical Reports Server (NTRS)

Stell, Laurel L.

2011-01-01

To enable arriving aircraft to fly optimized descents computed by the flight management system (FMS) in congested airspace, ground automation must accurately predict descent trajectories. To support development of the trajectory predictor and its error models, commercial flights executed idle-thrust descents, and the recorded data includes the target speed profile and FMS intent trajectories. The FMS computes the intended descent path assuming idle thrust after top of descent (TOD), and any intervention by the controllers that alters the FMS execution of the descent is recorded so that such flights are discarded from the analysis. The horizontal flight path, cruise and meter fix altitudes, and actual TOD location are extracted from the radar data. Using more than 60 descents in Boeing 777 aircraft, the actual speeds are compared to the intended descent speed profile. In addition, three aspects of the accuracy of the FMS intent trajectory are analyzed: the meter fix crossing time, the TOD location, and the altitude at the meter fix. The actual TOD location is within 5 nmi of the intent location for over 95% of the descents. Roughly 90% of the time, the airspeed is within 0.01 of the target Mach number and within 10 KCAS of the target descent CAS, but the meter fix crossing time is only within 50 sec of the time computed by the FMS. Overall, the aircraft seem to be executing the descents as intended by the designers of the onboard automation.

Test results of flight guidance for fuel conservative descents in a time-based metered air traffic environment. [terminal configured vehicle

NASA Technical Reports Server (NTRS)

Knox, C. E.; Person, L. H., Jr.

1981-01-01

The NASA developed, implemented, and flight tested a flight management algorithm designed to improve the accuracy of delivering an airplane in a fuel-conservative manner to a metering fix at a time designated by air traffic control. This algorithm provides a 3D path with time control (4D) for the TCV B-737 airplane to make an idle-thrust, clean configured (landing gear up, flaps zero, and speed brakes retracted) descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path is calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithms are described and flight test results are presented.

Preliminary test results of a flight management algorithm for fuel conservative descents in a time based metered traffic environment. [flight tests of an algorithm to minimize fuel consumption of aircraft based on flight time

NASA Technical Reports Server (NTRS)

Knox, C. E.; Cannon, D. G.

1979-01-01

A flight management algorithm designed to improve the accuracy of delivering the airplane fuel efficiently to a metering fix at a time designated by air traffic control is discussed. The algorithm provides a 3-D path with time control (4-D) for a test B 737 airplane to make an idle thrust, clean configured descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path is calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithms and the results of the flight tests are discussed.

Descent Advisor Preliminary Field Test

NASA Technical Reports Server (NTRS)

Green, Steven M.; Vivona, Robert A.; Sanford, Beverly

1995-01-01

A field test of the Descent Advisor (DA) automation tool was conducted at the Denver Air Route Traffic Control Center in September 1994. DA is being developed to assist Center controllers in the efficient management and control of arrival traffic. DA generates advisories, based on trajectory predictions, to achieve accurate meter-fix arrival times in a fuel efficient manner while assisting the controller with the prediction and resolution of potential conflicts. The test objectives were: (1) to evaluate the accuracy of DA trajectory predictions for conventional and flight-management system equipped jet transports, (2) to identify significant sources of trajectory prediction error, and (3) to investigate procedural and training issues (both air and ground) associated with DA operations. Various commercial aircraft (97 flights total) and a Boeing 737-100 research aircraft participated in the test. Preliminary results from the primary test set of 24 commercial flights indicate a mean DA arrival time prediction error of 2.4 seconds late with a standard deviation of 13.1 seconds. This paper describes the field test and presents preliminary results for the commercial flights.

Effects of aircraft and flight parameters on energy-efficient profile descents in time-based metered traffic

NASA Technical Reports Server (NTRS)

Dejarnette, F. R.

1984-01-01

Concepts to save fuel while preserving airport capacity by combining time based metering with profile descent procedures were developed. A computer algorithm is developed to provide the flight crew with the information needed to fly from an entry fix to a metering fix and arrive there at a predetermined time, altitude, and airspeed. The flight from the metering fix to an aim point near the airport was calculated. The flight path is divided into several descent and deceleration segments. Descents are performed at constant Mach numbers or calibrated airspeed, whereas decelerations occur at constant altitude. The time and distance associated with each segment are calculated from point mass equations of motion for a clean configuration with idle thrust. Wind and nonstandard atmospheric properties have a large effect on the flight path. It is found that uncertainty in the descent Mach number has a large effect on the predicted flight time. Of the possible combinations of Mach number and calibrated airspeed for a descent, only small changes were observed in the fuel consumed.

Air Traffic Management Technology Demonstration-1 Concept of Operations (ATD-1 ConOps), Version 2.0

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Johnson, William C.; Swenson, Harry N.; Robinson, John E.; Prevot, Tom; Callantine, Todd J.; Scardina, John; Greene, Michael

2013-01-01

This document is an update to the operations and procedures envisioned for NASA s Air Traffic Management (ATM) Technology Demonstration #1 (ATD-1). The ATD-1 Concept of Operations (ConOps) integrates three NASA technologies to achieve high throughput, fuel-efficient arrival operations into busy terminal airspace. They are Traffic Management Advisor with Terminal Metering (TMA-TM) for precise time-based schedules to the runway and points within the terminal area, Controller-Managed Spacing (CMS) decision support tools for terminal controllers to better manage aircraft delay using speed control, and Flight deck Interval Management (FIM) avionics and flight crew procedures to conduct airborne spacing operations. The ATD-1 concept provides de-conflicted and efficient operations of multiple arrival streams of aircraft, passing through multiple merge points, from top-of-descent (TOD) to the Final Approach Fix. These arrival streams are Optimized Profile Descents (OPDs) from en route altitude to the runway, using primarily speed control to maintain separation and schedule. The ATD-1 project is currently addressing the challenges of integrating the three technologies, and their implantation into an operational environment. The ATD-1 goals include increasing the throughput of high-density airports, reducing controller workload, increasing efficiency of arrival operations and the frequency of trajectory-based operations, and promoting aircraft ADS-B equipage.

NASA's ATM Technology Demonstration-1: Integrated Concept of Arrival Operations

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Swenson, Harry N.; Prevot, Thomas; Callantine, Todd J.

2012-01-01

This paper describes operations and procedures envisioned for NASA s Air Traffic Management (ATM) Technology Demonstration #1 (ATD-1). The ATD-1 Concept of Operations (ConOps) demonstration will integrate three NASA technologies to achieve high throughput, fuel-efficient arrival operations into busy terminal airspace. They are Traffic Management Advisor with Terminal Metering (TMA-TM) for precise time-based schedules to the runway and points within the terminal area, Controller-Managed Spacing (CMS) decision support tools for terminal controllers to better manage aircraft delay using speed control, and Flight deck Interval Management (FIM) avionics and flight crew procedures to conduct airborne spacing operations. The ATD-1 concept provides de-conflicted and efficient operations of multiple arrival streams of aircraft, passing through multiple merge points, from top-of-descent (TOD) to touchdown. It also enables aircraft to conduct Optimized Profile Descents (OPDs) from en route altitude to the runway, using primarily speed control to maintain separation and schedule. The ATD-1 project is currently addressing the challenges of integrating the three technologies, and implantation into an operational environment. Goals of the ATD-1 demonstration include increasing the throughput of high-density airports, reducing controller workload, increasing efficiency of arrival operations and the frequency of trajectory-based operations, and promoting aircraft ADS-B equipage.

Controller evaluations of the descent advisor automation aid

NASA Technical Reports Server (NTRS)

Tobias, Leonard; Volckers, Uwe; Erzberger, Heinz

1989-01-01

An automation aid to assist air traffic controllers in efficiently spacing traffic and meeting arrival times at a fix has been developed at NASA Ames Research Center. The automation aid, referred to as the descent advisor (DA), is based on accurate models of aircraft performance and weather conditions. The DA generates suggested clearances, including both top-of-descent point and speed profile data, for one or more aircraft in order to achieve specific time or distance separation objectives. The DA algorithm is interfaced with a mouse-based, menu-driven controller display that allows the air traffic controller to interactively use its accurate predictive capability to resolve conflicts and issue advisories to arrival aircraft. This paper focuses on operational issues concerning the utilization of the DA, specifically, how the DA can be used for prediction, intrail spacing, and metering. In order to evaluate the DA, a real time simulation was conducted using both current and retired controller subjects. Controllers operated in teams of two, as they do in the present environment; issues of training and team interaction will be discussed. Evaluations by controllers indicated considerable enthusiasm for the DA aid, and provided specific recommendations for using the tool effectively.

Mars Reconnaissance Orbiter Navigation Strategy for Dual Support of Insight and ExoMars Entry, Descent and Landing Demonstrator Module in 2016

NASA Technical Reports Server (NTRS)

Wagner, Sean V.; Menon, Premkumar R.; Chung, Min-Kun J.; Williams, Jessica L.

2015-01-01

Mars Reconnaissance Orbiter (MRO) will support NASA's InSight Mission and ESA's ExoMars Entry, Descent and Landing Demonstrator Module (EDM) in the fall of 2016 when both landers arrive at Mars. MRO provided relay support during the Entry, Descent and Landing (EDL) sequences of Mars Phoenix Lander in 2008 and the Mars Science Laboratory in 2012. Unlike these missions, MRO will coordinate between two EDL events separated by only three weeks: InSight on September 28, 2016 and EDM on October 19, 2016. This paper describes MRO Navigation's maneuver strategy to move MRO's ascending node to meet the In- Sight EDL phasing requirement and support EDM.

Radio Frequency Signals in Jupiter's Atmosphere

PubMed

Lanzerotti; Rinnert; Dehmel; Gliem; Krider; Uman; Bach

1996-05-10

During the Galileo probe's descent through Jupiter's atmosphere, under the ionosphere, the lightning and radio emission detector measured radio frequency signals at levels significantly above the probe's electromagnetic noise. The signal strengths at 3 and 15 kilohertz were relatively large at the beginning of the descent, decreased with depth to a pressure level of about 5 bars, and then increased slowly until the end of the mission. The 15-kilohertz signals show arrival direction anisotropies. Measurements of radio frequency wave forms show that the probe passed through an atmospheric region that did not support lightning within at least 100 kilometers and more likely a few thousand kilometers of the descent trajectory. The apparent opacity of the jovian atmosphere increases sharply at pressures greater than about 4 bars.

Development of advanced avionics systems applicable to terminal-configured vehicles

NASA Technical Reports Server (NTRS)

Heimbold, R. L.; Lee, H. P.; Leffler, M. F.

1980-01-01

A technique to add the time constraint to the automatic descent feature of the existing L-1011 aircraft Flight Management System (FMS) was developed. Software modifications were incorporated in the FMS computer program and the results checked by lab simulation and on a series of eleven test flights. An arrival time dispersion (2 sigma) of 19 seconds was achieved. The 4 D descent technique can be integrated with the time-based metering method of air traffic control. Substantial reductions in delays at today's busy airports should result.

Semiautomated Management Of Arriving Air Traffic

NASA Technical Reports Server (NTRS)

Erzberger, Heinz; Nedell, William

1992-01-01

System of computers, graphical workstations, and computer programs developed for semiautomated management of approach and arrival of numerous aircraft at airport. System comprises three subsystems: traffic-management advisor, used for controlling traffic into terminal area; descent advisor generates information integrated into plan-view display of traffic on monitor; and final-approach-spacing tool used to merge traffic converging on final approach path while making sure aircraft are properly spaced. Not intended to restrict decisions of air-traffic controllers.

Mars Science Laboratory Launch-Arrival Space Study: A Pork Chop Plot Analysis

NASA Technical Reports Server (NTRS)

Cianciolo, Alicia Dwyer; Powell, Richard; Lockwood, Mary Kae

2006-01-01

Launch-Arrival, or "pork chop", plot analysis can provide mission designers with valuable information and insight into a specific launch and arrival space selected for a mission. The study begins with the array of entry states for each pair of selected Earth launch and Mars arrival dates, and nominal entry, descent and landing trajectories are simulated for each pair. Parameters of interest, such as maximum heat rate, are plotted in launch-arrival space. The plots help to quickly identify launch and arrival regions that are not feasible under current constraints or technology and also provide information as to what technologies may need to be developed to reach a desired region. This paper provides a discussion of the development, application, and results of a pork chop plot analysis to the Mars Science Laboratory mission. This technique is easily applicable to other missions at Mars and other destinations.

Flight crew support for automated negotiation of descent and arrival clearances

DOT National Transportation Integrated Search

1997-01-01

This paper focuses on the application of data link for communication between air traffic management and FMS-equipped aircraft. Based on requirements and guidelines for data link usage, a general philosophy for automated data exchange and the distribu...

Paget's disease in patients of Asian descent in New Zealand.

PubMed

Sankaran, Shyam; Naot, Dorit; Grey, Andrew; Cundy, Tim

2012-01-01

Paget's disease is considered to be uncommon in Asian people, but we have noted a recent increase in the number of Asian patients referred to our clinic, on a background of an apparently decreasing prevalence in the population of European descent. In this article, we report clinical and epidemiological features of patients of Asian descent with Paget's disease, referred between 1973 and 2010 to the Auckland Paget's disease clinic. No Asian patients were referred before 1993, but 14 have presented between 1993 and 2010, with a median of 8 years between arrival into New Zealand and time of diagnosis. The patients were predominantly of south Asian origin. None of the 8 patients tested carried a mutation in exon 8 of the sequestosome 1 (SQSTM1) gene. The number of new Paget's disease referrals expressed as a proportion of the potentially at-risk Asian population in the Auckland region (derived from census data) was 1/10(4) in 2006 to 2011. Amongst Europeans, the corresponding value decreased from 10/10(4) in 1986 to 1991 to 2/10(4) in 2006 to 2010. The increased number of people of Asian descent diagnosed with Paget's disease in the Auckland region has paralleled the increasing size of the local Asian population. The continuing decline of Paget's disease in the European population, in conjunction with the emergence of the disease in the Asian population, supports the view that an environmental determinant to the disease exists and that Asians are not genetically protected. It also implies that the apparent reduction in Paget's disease prevalence in western cities is unlikely to be explicable by the rising Asian population of these cities. Copyright © 2012 American Society for Bone and Mineral Research.

Mission and Design Sensitivities for Human Mars Landers Using Hypersonic Inflatable Aerodynamic Decelerators

NASA Technical Reports Server (NTRS)

Polsgrove, Tara; Thomas, Herbert D.; Dwyer Cianciolo, Alicia; Collins, Tim; Samareh, Jamshid

2017-01-01

This paper explores the impact of human Mars mission architecture decisions on the design and performance of a lander using the HIAD entry system: (a) Earth departure options, (b) Mars arrival options, (c) Entry Descent and Landing options.

Design and evaluation of Continuous Descent Approach as a fuel-saving procedure

NASA Astrophysics Data System (ADS)

Jin, Li

Continuous Descent Approach (CDA), which is among the key concepts of the Next Generation Air Transportation System (NextGen), is a fuel economical procedure, but requires increased separation to accommodate spacing uncertainties among arriving aircraft. Such negative impact is often overlooked when benefits are estimated. Although a considerable number of researches have been devoted to the estimation of potential fuel saving of CDA, few have attempted to explain the fuel saving observed in field tests from an analytical point of view. This research gives insights into the reasons why CDA saves fuel, and a number of design guidelines for CDA procedures are derived. The analytical relationship between speed, altitude, and time-cumulative fuel consumption is derived based on Base of Aircraft Data (BADA) Total Energy Model. Theoretical analysis implies that speed profile has an impact as substantial as, if not more than, vertical profile on the fuel consumption in the terminal area. In addition, CDA is not intrinsically a fuel-saving procedure: whether CDA saves fuel or not is contingent upon whether the speed profile is properly designed or not. Based on this model, the potential fuel savings due to CDA at San Francisco International Airport were estimated, and the accuracy of this estimation is analyzed. Possible uncertainties in this fuel estimation primarily resulted from the modeled CDA procedure and the inaccuracy of BADA. This thesis also investigates the fuel savings due to CDAs under high traffic conditions, counting not only the savings benefiting from optimal vertical profiles but also the extra fuel burn resulting from the increased separations. The simulated CDAs traffic is based on radar track data, and deconflicted by a scheduling algorithm that targets minimized delays. The delays are absorbed by speed change and path stretching, accounting for the air traffic controls that are entailed by CDAs. The fuel burn statistics calculated based on the BADA Total Energy Model reveals that the CDAs save on average 171.87 kg per arrival, but the number is discounted by delay absorption. The savings diminish as the arrival demand increases, and could be even negative due to large delays. The throughput analysis demonstrated that the impact of CDA on airport capacity is insignificant and tolerable. The Atlanta International Airport was used as the testbed for sensitivity analysis, and the New York Metroplex was used as the test bed for throughput analysis.

Experiment Description and Results for Arrival Operations Using Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR)

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Murdoch, Jennifer L.; Swieringa, Kurt A.; Barmore, Bryan E.; Capron, William R.; Hubbs, Clay E.; Shay, Richard F.; Abbott, Terence S.

2013-01-01

The predicted increase in the number of commercial aircraft operations creates a need for improved operational efficiency. Two areas believed to offer increases in aircraft efficiency are optimized profile descents and dependent parallel runway operations. Using Flight deck Interval Management (FIM) software and procedures during these operations, flight crews can achieve by the runway threshold an interval assigned by air traffic control (ATC) behind the preceding aircraft that maximizes runway throughput while minimizing additional fuel consumption and pilot workload. This document describes an experiment where 24 pilots flew arrivals into the Dallas Fort-Worth terminal environment using one of three simulators at NASA?s Langley Research Center. Results indicate that pilots delivered their aircraft to the runway threshold within +/- 3.5 seconds of their assigned time interval, and reported low workload levels. In general, pilots found the FIM concept, procedures, speeds, and interface acceptable. Analysis of the time error and FIM speed changes as a function of arrival stream position suggest the spacing algorithm generates stable behavior while in the presence of continuous (wind) or impulse (offset) error. Concerns reported included multiple speed changes within a short time period, and an airspeed increase followed shortly by an airspeed decrease.

How to Compute a Slot Marker - Calculation of Controller Managed Spacing Tools for Efficient Descents with Precision Scheduling

NASA Technical Reports Server (NTRS)

Prevot, Thomas

2012-01-01

This paper describes the underlying principles and algorithms for computing the primary controller managed spacing (CMS) tools developed at NASA for precisely spacing aircraft along efficient descent paths. The trajectory-based CMS tools include slot markers, delay indications and speed advisories. These tools are one of three core NASA technologies integrated in NASAs ATM technology demonstration-1 (ATD-1) that will operationally demonstrate the feasibility of fuel-efficient, high throughput arrival operations using Automatic Dependent Surveillance Broadcast (ADS-B) and ground-based and airborne NASA technologies for precision scheduling and spacing.

Pilot and Controller Workload and Situation Awareness with Three Traffic Management Concept

NASA Technical Reports Server (NTRS)

Vu, Kim-Phuong L.; Strybel, Thomas Z.; Kraut, Joshua; Bacon, Paige; Minakata, Katsumi; Battiste, Vernol; Johnson, Walter

2010-01-01

This paper reports on workload and situation awareness of pilots and controllers participating in a human-in-the-loop simulation using three different distributed air-ground traffic management concepts. Eight experimental pilots started the scenario in an en-route phase of flight and were asked to avoid convective weather while performing spacing and merging tasks along with a continuous descent approach (CDA) into Louisville Standiford Airport (SDF). Two controllers managed the sectors through which the pilots flew, with one managing a sector that included the Top of Descent, and the other managing a sector that included the merge point for arrival into SDF. At 3-minute intervals in the scenario, pilots and controllers were probed on their workload or situation awareness. We employed one of three concepts of operation that distributed separation responsibility across human controllers, pilots, and automation to measure changes in operator situation awareness and workload. We found that when pilots were responsible for separation, they had higher levels of awareness, but not necessarily higher levels of workload. When controllers are responsible and actively engaged, they showed higher workload levels compared to pilots and changes in awareness that were dependent on sector characteristics.

Effects of aircraft and flight parameters on energy-efficient profile descents in time-based metered traffic

NASA Technical Reports Server (NTRS)

Dejarnette, F. R.

1984-01-01

Attention is given to a computer algorithm yielding the data required for a flight crew to navigate from an entry fix, about 100 nm from an airport, to a metering fix, and arrive there at a predetermined time, altitude, and airspeed. The flight path is divided into several descent and deceleration segments. Results for the case of a B-737 airliner indicate that wind and nonstandard atmospheric properties have a significant effect on the flight path and must be taken into account. While a range of combinations of Mach number and calibrated airspeed is possible for the descent segments leading to the metering fix, only small changes in the fuel consumed were observed for this range of combinations. A combination that is based on scheduling flexibility therefore seems preferable.

Regression Analysis of Top of Descent Location for Idle-thrust Descents

NASA Technical Reports Server (NTRS)

Stell, Laurel; Bronsvoort, Jesper; McDonald, Greg

2013-01-01

In this paper, multiple regression analysis is used to model the top of descent (TOD) location of user-preferred descent trajectories computed by the flight management system (FMS) on over 1000 commercial flights into Melbourne, Australia. The independent variables cruise altitude, final altitude, cruise Mach, descent speed, wind, and engine type were also recorded or computed post-operations. Both first-order and second-order models are considered, where cross-validation, hypothesis testing, and additional analysis are used to compare models. This identifies the models that should give the smallest errors if used to predict TOD location for new data in the future. A model that is linear in TOD altitude, final altitude, descent speed, and wind gives an estimated standard deviation of 3.9 nmi for TOD location given the trajec- tory parameters, which means about 80% of predictions would have error less than 5 nmi in absolute value. This accuracy is better than demonstrated by other ground automation predictions using kinetic models. Furthermore, this approach would enable online learning of the model. Additional data or further knowl- edge of algorithms is necessary to conclude definitively that no second-order terms are appropriate. Possible applications of the linear model are described, including enabling arriving aircraft to fly optimized descents computed by the FMS even in congested airspace. In particular, a model for TOD location that is linear in the independent variables would enable decision support tool human-machine interfaces for which a kinetic approach would be computationally too slow.

Design and Testing of a Low Noise Flight Guidance Concept

NASA Technical Reports Server (NTRS)

Williams, David H.; Oseguera-Lohr, Rosa M.; Lewis, Elliot T.

2004-01-01

A flight guidance concept was developed to assist in flying continuous descent approach (CDA) procedures designed to lower the noise under the flight path of jet transport aircraft during arrival operations at an airport. The guidance consists of a trajectory prediction algorithm that was tuned to produce a high-efficiency, low noise flight profile with accompanying autopilot and flight display elements needed by the flight control system and pilot to fly the approach. A key component of the flight guidance was a real-time display of energy error relative to the predicted flight path. The guidance was integrated with the conventional Flight Management System (FMS) guidance of a modern jet transport airplane and tested in a high fidelity flight simulation. A charted arrival procedure, which allowed flying conventional arrivals, CDA arrivals with standard guidance, and CDA arrivals with the new low noise guidance, was developed to assist in the testing and evaluation of the low noise guidance concept. Results of the simulation testing showed the low noise guidance was easy to use by airline pilot test subjects and effective in achieving the desired noise reduction. Noise under the flight path was reduced by at least 2 decibels in Sound Exposure Level (SEL) at distances from about 3 nautical miles out to about 17.5 nautical miles from the runway, with a peak reduction of 8.5 decibels at about 10.5 nautical miles. Fuel consumption was also reduced by about 17% for the LNG conditions compared to baseline runs for the same flight distance. Pilot acceptance and understanding of the guidance was quite high with favorable comments and ratings received from all test subjects.

Design of Center-TRACON Automation System

NASA Technical Reports Server (NTRS)

Erzberger, Heinz; Davis, Thomas J.; Green, Steven

1993-01-01

A system for the automated management and control of terminal area traffic, referred to as the Center-TRACON Automation System (CTAS), is being developed at NASA Ames Research Center. In a cooperative program, NASA and FAA have efforts underway to install and evaluate the system at the Denver area and Dallas/Ft. Worth area air traffic control facilities. This paper will review CTAS architecture, and automation functions as well as the integration of CTAS into the existing operational system. CTAS consists of three types of integrated tools that provide computer-generated advisories for both en-route and terminal area controllers to guide them in managing and controlling arrival traffic efficiently. One tool, the Traffic Management Advisor (TMA), generates runway assignments, landing sequences and landing times for all arriving aircraft, including those originating from nearby feeder airports. TMA also assists in runway configuration control and flow management. Another tool, the Descent Advisor (DA), generates clearances for the en-route controllers handling arrival flows to metering gates. The DA's clearances ensure fuel-efficient and conflict free descents to the metering gates at specified crossing times. In the terminal area, the Final Approach Spacing Tool (FAST) provides heading and speed advisories that help controllers produce an accurately spaced flow of aircraft on the final approach course. Data bases consisting of several hundred aircraft performance models, airline preferred operational procedures, and a three dimensional wind model support the operation of CTAS. The first component of CTAS, the Traffic Management Advisor, is being evaluated at the Denver TRACON and the Denver Air Route Traffic Control Center. The second component, the Final Approach Spacing Tool, will be evaluated in several stages at the Dallas/Fort Worth Airport beginning in October 1993. An initial stage of the Descent Advisor tool is being prepared for testing at the Denver Center in late 1994. Operational evaluations of all three integrated CTAS tools are expected to begin at the two field sites in 1995.

Improvement to Airport Throughput Using Intelligent Arrival Scheduling and an Expanded Planning Horizon

NASA Technical Reports Server (NTRS)

Glaab, Patricia C.

2012-01-01

The first phase of this study investigated the amount of time a flight can be delayed or expedited within the Terminal Airspace using only speed changes. The Arrival Capacity Calculator analysis tool was used to predict the time adjustment envelope for standard descent arrivals and then for CDA arrivals. Results ranged from 0.77 to 5.38 minutes. STAR routes were configured for the ACES simulation, and a validation of the ACC results was conducted comparing the maximum predicted time adjustments to those seen in ACES. The final phase investigated full runway-to-runway trajectories using ACES. The radial distance used by the arrival scheduler was incrementally increased from 50 to 150 nautical miles (nmi). The increased Planning Horizon radii allowed the arrival scheduler to arrange, path stretch, and speed-adjust flights to more fully load the arrival stream. The average throughput for the high volume portion of the day increased from 30 aircraft per runway for the 50 nmi radius to 40 aircraft per runway for the 150 nmi radius for a traffic set representative of high volume 2018. The recommended radius for the arrival scheduler s Planning Horizon was found to be 130 nmi, which allowed more than 95% loading of the arrival stream.

Analysis of Flight Management System Predictions of Idle-Thrust Descents

NASA Technical Reports Server (NTRS)

Stell, Laurel

2010-01-01

To enable arriving aircraft to fly optimized descents computed by the flight management system (FMS) in congested airspace, ground automation must accurately predict descent trajectories. To support development of the predictor and its uncertainty models, descents from cruise to the meter fix were executed using vertical navigation in a B737-700 simulator and a B777-200 simulator, both with commercial FMSs. For both aircraft types, the FMS computed the intended descent path for a specified speed profile assuming idle thrust after top of descent (TOD), and then it controlled the avionics without human intervention. The test matrix varied aircraft weight, descent speed, and wind conditions. The first analysis in this paper determined the effect of the test matrix parameters on the FMS computation of TOD location, and it compared the results to those for the current ground predictor in the Efficient Descent Advisor (EDA). The second analysis was similar but considered the time to fly a specified distance to the meter fix. The effects of the test matrix variables together with the accuracy requirements for the predictor will determine the allowable error for the predictor inputs. For the B737, the EDA prediction of meter fix crossing time agreed well with the FMS; but its prediction of TOD location probably was not sufficiently accurate to enable idle-thrust descents in congested airspace, even though the FMS and EDA gave similar shapes for TOD location as a function of the test matrix variables. For the B777, the FMS and EDA gave different shapes for the TOD location function, and the EDA prediction of the TOD location is not accurate enough to fully enable the concept. Furthermore, the differences between the FMS and EDA predictions of meter fix crossing time for the B777 indicated that at least one of them was not sufficiently accurate.

On Target to Mars

NASA Technical Reports Server (NTRS)

Cheng, Yang

2007-01-01

This viewgraph presentation reviews the use of Descent Image Motion Estimation System (DIMES) for the descent of a spacecraft onto the surface of Mars. In the past this system was used to assist in the landing of the MER spacecraft. The overall algorithm is reviewed, and views of the hardware, and views from Spirit's descent are shown. On Spirit, had DIMES not been used, the impact velocity would have been at the limit of the airbag capability and Spirit may have bounced into Endurance Crater. By using DIMES, the velocity was reduced to well within the bounds of the airbag performance and Spirit arrived safely at Mars. Views from Oppurtunity's descent are also shown. The system to avoid and detect hazards is reviewed next. Landmark Based Spacecraft Pinpoint Landing is also reviewed. A cartoon version of a pinpoint landing and the various points is shown. Mars s surface has a large amount of craters, which are ideal landmarks . According to literatures on Martian cratering, 60 % of Martian surface is heavily cratered. The ideal (craters) landmarks for pinpoint landing will be between 1000 to 50 meters in diagonal The ideal altitude for position estimation should greater than 2 km above the ground. The algorithms used to detect and match craters are reviewed.

Flight-Deck Strategies and Outcomes When Flying Schedule-Matching Descents

NASA Technical Reports Server (NTRS)

Kaneshige, John T.; Sharma, Shivanjli; Martin Lynne; Lozito, Sandra; Dulchinos, Victoria

2013-01-01

Recent studies at NASA Ames Research Center have investigated the development and use of ground-based (air traffic controller) tools to manage and schedule air traffic in future terminal airspace. An exploratory study was undertaken to investigate the impacts that such tools (and concepts) could have on the flight-deck. Ten Boeing 747-400 crews flew eight optimized profile descents in the Los Angeles terminal airspace, while receiving scripted current day and futuristic speed clearances, to ascertain their ability to fly schedulematching descents without prior training. Although the study was exploratory in nature, four variables were manipulated: route constraints, winds, speed changes, and clearance phraseology. Despite flying the same scenarios with the same events and timing, there were significant differences in the time it took crews to fly the approaches. This variation is the product of a number of factors but highlights potential difficulties for scheduling tools that would have to accommodate this amount of natural variation in descent times. The focus of this paper is the examination of the crews' aircraft management strategies and outcomes. This includes potentially problematic human-automation interaction issues that may negatively impact arrival times, speed and altitude constraint compliance, and energy management efficiency.

ExoMars 2016 arrives at Mars

NASA Astrophysics Data System (ADS)

Svedhem, Hakan; Vago, Jorge L.; ExoMars Team

2016-10-01

The Trace Gas Orbiter (TGO) and the Schiaparelli Entry, descent and landing Demonstrator Model (EDM) will arrive at Mars on 19 October 2016. The TGO and the EDM are part of the first step of the ExoMars Programme. They will be followed by a Rover and a long lived Surface Platform to be launched in 2020.The EDM is attached to the TGO for the full duration of the cruise to Mars and will be separated three days before arrival at Mars. After separation the TGO will perform a deflection manoeuvre and, on 19 October (during the EDM landing), enter into a highly elliptical near equatorial orbit. TGO will remain in this parking orbit until January 2017, when the orbital plane inclination will be changed to 74 degrees and aerobraking to the final 400 km near circular orbit will start. The final operational orbit is expected to be reached at the end of 2017.The TGO scientific payload consists of four instruments. These are: ACS and NOMAD, both infrared spectrometers for atmospheric measurements in solar occultation mode and in nadir mode, CASSIS, a multichannel camera with stereo imaging capability, and FREND, an epithermal neutron detector for search of subsurface hydrogen. The mass of the TGO is 3700 kg, including fuel. The EDM, with a mass of 600 kg, is mounted on top of the TGO as seen in its launch configuration. The main objective of the EDM is to demonstrate the capability of performing a safe entry, descent and landing on the surface, but it does carry a descent camera and a small battery powered meteorological package that may operate for a few days on the surface.The ExoMars programme is a joint activity by the European Space Agency(ESA) and ROSCOSMOS, Russia. ESA is providing the TGO spacecraft and Schiaparelli (EDM) and two of the TGO instruments and ROSCOSMOS is providing the launcher and the other two TGO instruments. After the arrival of the ExoMars 2020 mission at the surface of Mars, the TGO will handle the communication between the Earth and the Rover and Surface Platform through its (NASA provided) UHF communication system. The 2016 mission was launched by a Russian Proton rocket from Baikonur on 14 March 2016.

Flight Mechanics of the Entry, Descent and Landing of the ExoMars Mission

NASA Technical Reports Server (NTRS)

HayaRamos, Rodrigo; Boneti, Davide

2007-01-01

ExoMars is ESA's current mission to planet Mars. A high mobility rover and a fixed station will be deployed on the surface of Mars. This paper regards the flight mechanics of the Entry, Descent and Landing (EDL) phases used for the mission analysis and design of the Baseline and back-up scenarios of the mission. The EDL concept is based on a ballistic entry, followed by a descent under parachutes and inflatable devices (airbags) for landing. The mission analysis and design is driven by the flexibility in terms of landing site, arrival dates and the very stringent requirement in terms of landing accuracy. The challenging requirements currently imposed to the mission need innovative analysis and design techniques to support system design trade-offs to cope with the variability in entry conditions. The concept of the Global Entry Corridor has been conceived, designed, implemented and successfully validated as a key tool to provide a global picture of the mission capabilities in terms of landing site reachability.

Design and Evaluation of the Terminal Area Precision Scheduling and Spacing System

NASA Technical Reports Server (NTRS)

Swenson, Harry N.; Thipphavong, Jane; Sadovsky, Alex; Chen, Liang; Sullivan, Chris; Martin, Lynne

2011-01-01

This paper describes the design, development and results from a high fidelity human-in-the-loop simulation of an integrated set of trajectory-based automation tools providing precision scheduling, sequencing and controller merging and spacing functions. These integrated functions are combined into a system called the Terminal Area Precision Scheduling and Spacing (TAPSS) system. It is a strategic and tactical planning tool that provides Traffic Management Coordinators, En Route and Terminal Radar Approach Control air traffic controllers the ability to efficiently optimize the arrival capacity of a demand-impacted airport while simultaneously enabling fuel-efficient descent procedures. The TAPSS system consists of four-dimensional trajectory prediction, arrival runway balancing, aircraft separation constraint-based scheduling, traffic flow visualization and trajectory-based advisories to assist controllers in efficient metering, sequencing and spacing. The TAPSS system was evaluated and compared to today's ATC operation through extensive series of human-in-the-loop simulations for arrival flows into the Los Angeles International Airport. The test conditions included the variation of aircraft demand from a baseline of today's capacity constrained periods through 5%, 10% and 20% increases. Performance data were collected for engineering and human factor analysis and compared with similar operations both with and without the TAPSS system. The engineering data indicate operations with the TAPSS show up to a 10% increase in airport throughput during capacity constrained periods while maintaining fuel-efficient aircraft descent profiles from cruise to landing.

Computer-Aided Air-Traffic Control In The Terminal Area

NASA Technical Reports Server (NTRS)

Erzberger, Heinz

1995-01-01

Developmental computer-aided system for automated management and control of arrival traffic at large airport includes three integrated subsystems. One subsystem, called Traffic Management Advisor, another subsystem, called Descent Advisor, and third subsystem, called Final Approach Spacing Tool. Data base that includes current wind measurements and mathematical models of performances of types of aircraft contributes to effective operation of system.

Vertical Compliance Trends in KBOS OPD Arrival Redesign

NASA Technical Reports Server (NTRS)

Stewart, Michael Jeffrey; Matthews, Bryan L.; Feary, Michael S.

2016-01-01

This report is a high-level summary of vertical compliance trends and overall rates of Area Navigation Optimized Profile Descent (RNAV OPD) utilization for Boston Logan International Airport. Specifically, we investigated trends from three RNAV OPDs and the subsequent redesigned iterations of those procedures: OOSHN3 to OOSHN4, ROBUC1 to ROBUC2, and QUABN3 to JFUND1.

ExoMars Mission Analysis and Design - Launch, Cruise and Arrival Analyses

NASA Technical Reports Server (NTRS)

Cano, Juan L.; Cacciatore, Francesco

2007-01-01

ExoMars is ESA s next mission to planet Mars. The probe is aimed for launch either in 2013 or in 2016. The project is currently undergoing Phase B1 studies under ESA management and Thales Alenia Space Italia project leadership. In that context, DEIMOS Space is responsible for the Mission Analysis and Design for the interplanetary and the entry, descent and landing (EDL) activities. The present mission baseline is based on an Ariane 5 or Proton M launch in 2013 of a spacecraft Composite bearing a Carrier Module (CM) and a Descent Module (DM). A back-up option is proposed in 2016. This paper presents the current status of the interplanetary mission design from launch up to the start of the EDL phase.

Reduced-gravity Testing of The Huygens Probe Ssp Tiltmeter and Hasi Accelerometer Sensors and Their Role In Reconstruction of The Probe Descent Dynamics

NASA Astrophysics Data System (ADS)

Ghafoor, N.; Zarnecki, J.

When the ESA Huygens Probe arrives at Titan in 2005, measurements taken during and after the descent through the atmosphere are likely to revolutionise our under- standing of SaturnSs most enigmatic moon. The accurate atmospheric profiling of Titan from these measurements will require knowledge of the probe descent trajectory and in some cases attitude history, whilst certain atmospheric information (e.g. wind speeds) may be inferred directly from the probe dynamics during descent. Two of the instruments identified as contributing valuable information for the reconstruction of the probeSs parachute descent dynamics are the Surface Science Package Tilt sensor (SSP-TIL) and the Huygens Atmospheric Structure Instrument servo accelerometer (HASI-ACC). This presentation provides an overview of these sensors and their static calibration before describing an investigation into their real-life dynamic performance under simulated Titan-gravity conditions via a low-cost parabolic flight opportunity. The combined use of SSP-TIL and HASI-ACC in characterising the aircraft dynam- ics is also demonstrated and some important challenges are highlighted. Results from some simple spin tests are also presented. Finally, having validated the performance of the sensors under simulated Titan conditions, estimates are made as to the output of SSP-TIL and HASI-ACC under a variety of probe dynamics, ranging from verti- cal descent with spin to a simple 3 degree-of-freedom parachute descent model with horizontal gusting. It is shown how careful consideration must be given to the instru- mentsS principles of operation in each case, and also the impact of the sampling rates and resolutions as selected for the Huygens mission. The presentation concludes with a discussion of ongoing work on more advanced descent modelling and surface dy- namics modelling, and also of a proposal for the testing of the sensors on a sea-surface.

Development, design, and flight test evaluation of a continuous descent approach procedure for nighttime operation at Louisville International Airport.

DOT National Transportation Integrated Search

2006-01-09

The design and flight test of a Continuous Descent Approach (CDA) : procedure for regular nighttime operation at Louisville : International Airport are described in this report. Results of : the analyses of aircraft and FMS performance indicate that ...

Air Traffic Management Technology Demonstration-1 Concept of Operations (ATD-1 ConOps)

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Johnson, William C.; Swenson, Harry; Robinson, John E.; Prevot, Thomas; Callantine, Todd; Scardina, John; Greene, Michael

2012-01-01

The operational goal of the ATD-1 ConOps is to enable aircraft, using their onboard FMS capabilities, to fly Optimized Profile Descents (OPDs) from cruise to the runway threshold at a high-density airport, at a high throughput rate, using primarily speed control to maintain in-trail separation and the arrival schedule. The three technologies in the ATD-1 ConOps achieve this by calculating a precise arrival schedule, using controller decision support tools to provide terminal controllers with speeds for aircraft to fly to meet times at a particular meter points, and onboard software providing flight crews with speeds for the aircraft to fly to achieve a particular spacing behind preceding aircraft.

Initial Investigations of Controller Tools and Procedures for Schedule-Based Arrival Operations with Mixed Flight-Deck Interval Management Equipage

NASA Technical Reports Server (NTRS)

Callantine, Todd J.; Cabrall, Christopher; Kupfer, Michael; Omar, Faisal G.; Prevot, Thomas

2012-01-01

NASA?s Air Traffic Management Demonstration-1 (ATD-1) is a multi-year effort to demonstrate high-throughput, fuel-efficient arrivals at a major U.S. airport using NASA-developed scheduling automation, controller decision-support tools, and ADS-B-enabled Flight-Deck Interval Management (FIM) avionics. First-year accomplishments include the development of a concept of operations for managing scheduled arrivals flying Optimized Profile Descents with equipped aircraft conducting FIM operations, and the integration of laboratory prototypes of the core ATD-1 technologies. Following each integration phase, a human-in-the-loop simulation was conducted to evaluate and refine controller tools, procedures, and clearance phraseology. From a ground-side perspective, the results indicate the concept is viable and the operations are safe and acceptable. Additional training is required for smooth operations that yield notable benefits, particularly in the areas of FIM operations and clearance phraseology.

Highly Automated Arrival Management and Control System Suitable for Early NextGen

NASA Technical Reports Server (NTRS)

Swenson, Harry N.; Jung, Jaewoo

2013-01-01

This is a presentation of previously published work conducted in the development of the Terminal Area Precision Scheduling and Spacing (TAPSS) system. Included are concept and technical descriptions of the TAPSS system and results from human in the loop simulations conducted at Ames Research Center. The Terminal Area Precision Scheduling and Spacing system has demonstrated through research and extensive high-fidelity simulation studies to have benefits in airport arrival throughput, supporting efficient arrival descents, and enabling mixed aircraft navigation capability operations during periods of high congestion. NASA is currently porting the TAPSS system into the FAA TBFM and STARS system prototypes to ensure its ability to operate in the FAA automation Infrastructure. NASA ATM Demonstration Project is using the the TAPSS technologies to provide the ground-based automation tools to enable airborne Interval Management (IM) capabilities. NASA and the FAA have initiated a Research Transition Team to enable potential TAPSS and IM Technology Transfer.

The ExoMars 2016 Mission arriving at Mars

NASA Astrophysics Data System (ADS)

Svedhem, H.; Vago, J. L.

2016-12-01

The ExoMars 2016 mission was launched on a Proton rocket from Baikonur, Kazakhstan, on 14 March 2016 and is scheduled to arrive at Mars on 19 October 2016. ExoMars is a joint programme of the European Space Agency (ESA) and Roscosmos, Russia. It consists of the ExoMars 2016 mission with the Trace Gas Orbiter, TGO, and the Entry Descent and Landing Demonstrator, EDM, named Schiaparelli, and the ExoMars 2020 mission, which carries a lander and a rover. The TGO scientific payload consists of four instruments. These are: ACS and NOMAD, both infrared spectrometers for atmospheric measurements in solar occultation mode and in nadir mode, CASSIS, a multichannel camera with stereo imaging capability, and FREND, an epithermal neutron detector to search for subsurface hydrogen (as proxy for water ice and hydrated minerals). The mass of the TGO is 3700 kg, including fuel. The EDM, with a mass of 600 kg, is mounted on top of the TGO as seen in its launch configuration. The EDM is carried to Mars by the TGO and is separated three days before arrival at Mars. In addition to demonstrating the landing capability two scientific investigations are included with the EDM. The AMELIA investigation aims at characterising the Martian atmosphere during the entry and descent using technical and engineering sensors of the EDM, and the DREAMS suite of sensors that will characterise the environment of the landing site for a few days after the landing. ESA provides the TGO spacecraft and the Schiaparelli Lander demonstrator, ESA member states provide two of the TGO instruments and Roscosmos provides the launcher and the other two TGO instruments. After the arrival of the ExoMars 2020 mission at the surface of Mars, the TGO will handle all communications between the Earth and the Rover. The communication between TGO and the rover/lander is done through a UHF communications system, a contribution from NASA. This presentation will cover a description of the 2016 mission, including the spacecraft, its payload and science and the related plans for scientific operations and measurements, a summary of the activities since arrival, and, if available, some first results of the mission.

Mission and Navigation Design for the 2009 Mars Science Laboratory Mission

NASA Technical Reports Server (NTRS)

D'Amario, Louis A.

2008-01-01

NASA s Mars Science Laboratory mission will launch the next mobile science laboratory to Mars in the fall of 2009 with arrival at Mars occurring in the summer of 2010. A heat shield, parachute, and rocket-powered descent stage, including a sky crane, will be used to land the rover safely on the surface of Mars. The direction of the atmospheric entry vehicle lift vector will be controlled by a hypersonic entry guidance algorithm to compensate for entry trajectory errors and counteract atmospheric and aerodynamic dispersions. The key challenges for mission design are (1) develop a launch/arrival strategy that provides communications coverage during the Entry, Descent, and Landing phase either from an X-band direct-to-Earth link or from a Ultra High Frequency link to the Mars Reconnaissance Orbiter for landing latitudes between 30 deg North and 30 deg South, while satisfying mission constraints on Earth departure energy and Mars atmospheric entry speed, and (2) generate Earth-departure targets for the Atlas V-541 launch vehicle for the specified launch/arrival strategy. The launch/arrival strategy employs a 30-day baseline launch period and a 27-day extended launch period with varying arrival dates at Mars. The key challenges for navigation design are (1) deliver the spacecraft to the atmospheric entry interface point (Mars radius of 3522.2 km) with an inertial entry flight path angle error of +/- 0.20 deg (3 sigma), (2) provide knowledge of the entry state vector accurate to +/- 2.8 km (3 sigma) in position and +/- 2.0 m/s (3 sigma) in velocity for initializing the entry guidance algorithm, and (3) ensure a 99% probability of successful delivery at Mars with respect to available cruise stage propellant. Orbit determination is accomplished via ground processing of multiple complimentary radiometric data types: Doppler, range, and Delta-Differential One-way Ranging (a Very Long Baseline Interferometry measurement). The navigation strategy makes use of up to five interplanetary trajectory correction maneuvers to achieve entry targeting requirements. The requirements for cruise propellant usage and atmospheric entry targeting and knowledge are met with ample margins.

Titan's Surface Diversity and Ongoing Processes-A Review

NASA Astrophysics Data System (ADS)

Soderblom, Laurence A.

2012-04-01

Titan’s landscapes exhibit a wealth of surface diversity that rivals the glossary for a textbook on Earth’s geomorphological styles and geological processes. Long before Cassini-Huygens’ arrival, evidence suggested that Titan’s surface might harbor liquid hydrocarbons, methane and ethane, in the form of lakes, seas, or even oceans. And, as the surface gradually became visible to the Huygens Probe on its slow descent, it became clear that liquids had been quite active in sculpting and dissecting the terrains: a network of dendritic channels densely drapes the highlands located a few kilometers north of the landing site. This led Tomasko and colleagues to lead off the title of their Huygens report with “Rain, winds and haze …” And not only were winds responsible for the Probe’s erratic change in direction as it neared the surface but soon we discovered that they also drive vast seas of longitudinal dunes eastward, wrapping the equatorial zone. Current thinking is that the dunes consist of coarse grains of solid hydrocarbons, perhaps mixed with water ice, that saltate in the slow-moving dense atmosphere. And, although we did not find vast methane-ethane oceans, we did find polar lakes and seas, vast in the north and sparse in the south. Elsewhere impact, tectonic, and, more arguably, volcanic features appear to be ubiquitous. The subjects of Titan’s geology continue to cascade into a host of new details of the subjects of process and geomorphology; the collection terms, familiar to terrestrial science, continues to grow. References: Tomasko, M. G., et al. (2005) “Rain, winds and haze during the Huygens probe’s descent to Titan’s surface”. Nature, Vol. 438, pp.775-778.

Groundwater Productivity and Quality of The Quartzite Ridge of RÓdA~o and Their Vicinities (center of Portugal)

NASA Astrophysics Data System (ADS)

Duque, J.; Chambel, A.

When the ESA Huygens Probe arrives at Titan in 2005, measurements taken during and after the descent through the atmosphere are likely to revolutionise our under- standing of SaturnSs most enigmatic moon. The accurate atmospheric profiling of Titan from these measurements will require knowledge of the probe descent trajectory and in some cases attitude history, whilst certain atmospheric information (e.g. wind speeds) may be inferred directly from the probe dynamics during descent. Two of the instruments identified as contributing valuable information for the reconstruction of the probeSs parachute descent dynamics are the Surface Science Package Tilt sensor (SSP-TIL) and the Huygens Atmospheric Structure Instrument servo accelerometer (HASI-ACC). This presentation provides an overview of these sensors and their static calibration before describing an investigation into their real-life dynamic performance under simulated Titan-gravity conditions via a low-cost parabolic flight opportunity. The combined use of SSP-TIL and HASI-ACC in characterising the aircraft dynam- ics is also demonstrated and some important challenges are highlighted. Results from some simple spin tests are also presented. Finally, having validated the performance of the sensors under simulated Titan conditions, estimates are made as to the output of SSP-TIL and HASI-ACC under a variety of probe dynamics, ranging from verti- cal descent with spin to a simple 3 degree-of-freedom parachute descent model with horizontal gusting. It is shown how careful consideration must be given to the instru- mentsS principles of operation in each case, and also the impact of the sampling rates and resolutions as selected for the Huygens mission. The presentation concludes with a discussion of ongoing work on more advanced descent modelling and surface dy- namics modelling, and also of a proposal for the testing of the sensors on a sea-surface.

Model of aircraft passenger acceptance

NASA Technical Reports Server (NTRS)

Jacobson, I. D.

1978-01-01

A technique developed to evaluate the passenger response to a transportation system environment is described. Reactions to motion, noise, temperature, seating, ventilation, sudden jolts and descents are modeled. Statistics are presented for the age, sex, occupation, and income distributions of the candidates analyzed. Values are noted for the relative importance of system variables such as time savings, on-time arrival, convenience, comfort, safety, the ability to read and write, and onboard services.

Planetary Atmosphere Dynamics and Radiative Transfer

NASA Technical Reports Server (NTRS)

Atkinson, David H.

1996-01-01

This research program has dealt with two projects in the field of planetary atmosphere dynamics and radiative energy transfer, one theoretical and one experimental. The first project, in radiative energy transfer, incorporated the capability to isolate and quantify the contribution of individual atmospheric components to the Venus radiative balance and thermal structure to greatly improve the current understanding of the radiative processes occurring within the Venus atmosphere. This is possible by varying the mixing ratios of each gas species, and the location, number density and aerosol size distributions of the clouds. This project was a continuation of the work initiated under a 1992 University Consortium Agreement. Under the just completed grant, work has continued on the use of a convolution-based algorithm that provided the capability to calculate the k coefficients of a gas mixture at different temperatures, pressures and spectral intervals from the separate k-distributions of the individual gas species. The second primary goal of this research dealt with the Doppler wind retrieval for the Successful Galileo Jupiter probe mission in December, 1995. In anticipation of the arrival of Galileo at Jupiter, software development continued to read the radioscience and probe/orbiter trajectory data provided by the Galileo project and required for Jupiter zonal wind measurements. Sample experiment radioscience data records and probe/orbiter trajectory data files provided by the Galileo Radioscience and Navigation teams at the Jet Propulsion Laboratory, respectively, were used for the first phase of the software development. The software to read the necessary data records was completed in 1995. The procedure by which the wind retrieval takes place begins with initial consistency checks of the raw data, preliminary data reductions, wind recoveries, iterative reconstruction of the probe descent profile, and refined wind recoveries. At each stage of the wind recovery consistency is checked and maintained between the orbiter navigational data, the radioscience data, and the probe descent profile derived by the Atmospheric Instrument Team. Preliminary results show that the zonal winds at Jupiter increase with depth to approximately 150 m/s.

Flight test experience using advanced airborne equipment in a time-based metered traffic environment

NASA Technical Reports Server (NTRS)

Morello, S. A.

1980-01-01

A series of test flights have demonstrated that time-based metering guidance and control was acceptable to pilots and air traffic controllers. The descent algorithm of the technique, with good representation of aircraft performance and wind modeling, yielded arrival time accuracy within 12 sec. It is expected that this will represent significant fuel savings (1) through a reduction of the time error dispersions at the metering fix for the entire fleet, and (2) for individual aircraft as well, through the presentation of guidance for a fuel-efficient descent. Air traffic controller workloads were also reduced, in keeping with the reduction of required communications resulting from the transfer of navigation responsibilities to pilots. A second series of test flights demonstrated that an existing flight management system could be modified to operate in the new mode.

On Belonging: The American Adolescent of Arab Descent.

PubMed

Khouri, Lama Z

2016-08-01

Although American families of Arab origin come from 22 countries and from varied backgrounds and cultures, reports suggest that they suffer equally from acculturation stress, stereotyping, discrimination, and the reverberations of the aftermath of September 11 as well as global affairs. However, because children and adolescents from these families, particularly those who are newly arrived immigrants, tend to do well in school, they are rarely targeted by research or policy. This article uses the narratives of 5 middle school age male students from Arab descent who were in a support group that met for 3 years (2004-2007), beginning shortly after President George W. Bush's declaration of the war on the "axis of evil." I used vignettes from this group to illustrate the stressors this population faces. The final section suggests an option for supporting this population. © 2016 Wiley Periodicals, Inc.

Evaluation of an Airborne Spacing Concept, On-Board Spacing Tool, and Pilot Interface

NASA Technical Reports Server (NTRS)

Swieringa, Kurt; Murdoch, Jennifer L.; Baxley, Brian; Hubbs, Clay

2011-01-01

The number of commercial aircraft operations is predicted to increase in the next ten years, creating a need for improved operational efficiency. Two areas believed to offer significant increases in efficiency are optimized profile descents and dependent parallel runway operations. It is envisioned that during both of these types of operations, flight crews will precisely space their aircraft behind preceding aircraft at air traffic control assigned intervals to increase runway throughput and maximize the use of existing infrastructure. This paper describes a human-in-the-loop experiment designed to study the performance of an onboard spacing algorithm and pilots ratings of the usability and acceptability of an airborne spacing concept that supports dependent parallel arrivals. Pilot participants flew arrivals into the Dallas Fort-Worth terminal environment using one of three different simulators located at the National Aeronautics and Space Administration s (NASA) Langley Research Center. Scenarios were flown using Interval Management with Spacing (IM-S) and Required Time of Arrival (RTA) control methods during conditions of no error, error in the forecast wind, and offset (disturbance) to the arrival flow. Results indicate that pilots delivered their aircraft to the runway threshold within +/- 3.5 seconds of their assigned arrival time and reported that both the IM-S and RTA procedures were associated with low workload levels. In general, pilots found the IM-S concept, procedures, speeds, and interface acceptable; with 92% of pilots rating the procedures as complete and logical, 218 out of 240 responses agreeing that the IM-S speeds were acceptable, and 63% of pilots reporting that the displays were easy to understand and displayed in appropriate locations. The 22 (out of 240) responses, indicating that the commanded speeds were not acceptable and appropriate occurred during scenarios containing wind error and offset error. Concerns cited included the occurrence of multiple speed changes within a short time period, speed changes required within twenty miles of the runway, and an increase in airspeed followed shortly by a decrease in airspeed. Within this paper, appropriate design recommendations are provided, and the need for continued, iterative human-centered design is discussed.

KSC-2011-7097

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7093

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Under the watchful eyes of technicians at the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, a rocket-powered descent stage, after being lowered by an overhead crane, is integrated with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7101

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7079

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, an overhead crane is being lowered over a rocket-powered descent stage for integration with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7076

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, will be integrated with a rocket-powered descent stage. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7103

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7095

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7096

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7088

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Preparing for integration to NASA's Mars Science Laboratory (MSL) rover known as Curiosity, technicians help guide a rocket-powered descent stage over the rover at NASA's Kennedy Space Center Payload Hazardous Servicing Facility. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7086

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, an overhead crane lifts a rocket-powered descent stage for integration with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7075

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, will be integrated with a rocket-powered descent stage. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7087

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Preparing for integration to NASA's Mars Science Laboratory (MSL) rover known as Curiosity, technicians help guide a rocket-powered descent stage over the rover at NASA's Kennedy Space Center Payload Hazardous Servicing Facility. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7100

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7102

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7089

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Under the watchful eyes of technicians at the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, an overhead crane lowers a rocket-powered descent stage over NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, for integration. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7083

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Technicians, at the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, use an overhead crane to move a rocket-powered descent stage for integration with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7099

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7091

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Technicians at the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, guide an overhead crane as it lowers a rocket-powered descent stage over NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, for integration. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7085

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Under the watchful eyes of technicians at the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, an overhead crane begins lifting a rocket-powered descent stage for integration with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7094

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, a rocket-powered descent stage, after being lowered by an overhead crane, is integrated with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7098

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, integration between a rocket-powered descent stage and NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, is complete. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7077

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, will be integrated with a rocket-powered descent stage (shown here to the left of the rover). The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7092

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Under the watchful eyes of technicians at the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, a rocket-powered descent stage, after being lowered by an overhead crane, is integrated with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7074

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, technicians prepare NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, for integration with a rocket-powered descent stage. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7090

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – Technicians at the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, guide an overhead crane as it lowers a rocket-powered descent stage over NASA's Mars Science Laboratory (MSL) rover, known as Curiosity, for integration. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7078

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, technicians dressed in clean room attire, known as "bunny" suits, prepare a rocket-powered descent stage for integration with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7081

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, technicians carefully monitor the attachment of an overhead crane to a rocket-powered descent stage which will be integrated with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

KSC-2011-7084

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, technicians use an overhead crane to move a rocket-powered descent stage for integration with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity. The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

2011 Mars Science Laboratory Mission Design Overview

NASA Technical Reports Server (NTRS)

Abilleira, Fernando

2010-01-01

Scheduled to launch in the fall of 2011 with arrival at Mars occurring in the summer of 2012, NASA's Mars Science Laboratory will explore and assess whether Mars ever had conditions capable of supporting microbial life. In order to achieve its science objectives, the Mars Science Laboratory will be equipped with the most advanced suite of instruments ever sent to the surface of the Red Planet. Delivering the next mobile science laboratory safely to the surface of Mars has various key challenges derived from a strict set of requirements which include launch vehicle performance, spacecraft mass, communications coverage during Entry, Descent, and Landing, atmosphere-relative entry speeds, latitude accessibility, and dust storm season avoidance among others. The Mars Science Laboratory launch/arrival strategy selected after careful review satisfies all these mission requirements.

A Perspective on NASA Ames Air Traffic Management Research

NASA Technical Reports Server (NTRS)

Schroeder, Jeffery A.

2012-01-01

This paper describes past and present air-traffic-management research at NASA Ames Research Center. The descriptions emerge from the perspective of a technical manager who supervised the majority of this research for the last four years. Past research contributions built a foundation for calculating accurate flight trajectories to enable efficient airspace management in time. That foundation led to two predominant research activities that continue to this day - one in automatically separating aircraft and the other in optimizing traffic flows. Today s national airspace uses many of the applications resulting from research at Ames. These applications include the nationwide deployment of the Traffic Management Advisor, new procedures enabling continuous descent arrivals, cooperation with industry to permit more direct flights to downstream way-points, a surface management system in use by two cargo carriers, and software to evaluate how well flights conform to national traffic management initiatives. The paper concludes with suggestions for prioritized research in the upcoming years. These priorities include: enabling more first-look operational evaluations, improving conflict detection and resolution for climbing or descending aircraft, and focusing additional attention on the underpinning safety critical items such as a reliable datalink.

Operational Concept for Flight Crews to Participate in Merging and Spacing of Aircraft

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Barmore, Bryan E.; Abbott, Terence S.; Capron, William R.

2006-01-01

The predicted tripling of air traffic within the next 15 years is expected to cause significant aircraft delays and create a major financial burden for the airline industry unless the capacity of the National Airspace System can be increased. One approach to improve throughput and reduce delay is to develop new ground tools, airborne tools, and procedures to reduce the variance of aircraft delivery to the airport, thereby providing an increase in runway throughput capacity and a reduction in arrival aircraft delay. The first phase of the Merging and Spacing Concept employs a ground based tool used by Air Traffic Control that creates an arrival time to the runway threshold based on the aircraft s current position and speed, then makes minor adjustments to that schedule to accommodate runway throughput constraints such as weather and wake vortex separation criteria. The Merging and Spacing Concept also employs arrival routing that begins at an en route metering fix at altitude and continues to the runway threshold with defined lateral, vertical, and velocity criteria. This allows the desired spacing interval between aircraft at the runway to be translated back in time and space to the metering fix. The tool then calculates a specific speed for each aircraft to fly while enroute to the metering fix based on the adjusted land timing for that aircraft. This speed is data-linked to the crew who fly this speed, causing the aircraft to arrive at the metering fix with the assigned spacing interval behind the previous aircraft in the landing sequence. The second phase of the Merging and Spacing Concept increases the timing precision of the aircraft delivery to the runway threshold by having flight crews using an airborne system make minor speed changes during enroute, descent, and arrival phases of flight. These speed changes are based on broadcast aircraft state data to determine the difference between the actual and assigned time interval between the aircraft pair. The airborne software then calculates a speed adjustment to null that difference over the remaining flight trajectory. Follow-on phases still under development will expand the concept to all types of aircraft, arriving from any direction, merging at different fixes and altitudes, and to any airport. This paper describes the implementation phases of the Merging and Spacing Concept, and provides high-level results of research conducted to date.

The Double Star Orbit Initial Value Problem

NASA Astrophysics Data System (ADS)

Hensley, Hagan

2018-04-01

Many precise algorithms exist to find a best-fit orbital solution for a double star system given a good enough initial value. Desmos is an online graphing calculator tool with extensive capabilities to support animations and defining functions. It can provide a useful visual means of analyzing double star data to arrive at a best guess approximation of the orbital solution. This is a necessary requirement before using a gradient-descent algorithm to find the best-fit orbital solution for a binary system.

Proposed Force Structure for the Australian Army to Perform Maneuver Operations in the Littoral Environment within the Region of Interest

DTIC Science & Technology

2004-06-18

expectations grows in the soil enriched by observations of the wealthy living in close proximity, by oppression of those new rural arrivals and the...wary of treading on eggshells . Action was required and plainly the Indonesian military proved unable or unwilling to prevent the descent into anarchy...successfully on another country’s sovereign soil requires cultural sensitivity, especially if there is a demonstrated anxiety within the populace to the

Time-specific androgen blockade with flutamide inhibits testicular descent in the rat.

PubMed

Husmann, D A; McPhaul, M J

1991-09-01

Inhibition of androgen action by flutamide, a nonsteroidal antiandrogen, blocked testicular descent in 40% of the testes exposed to this agent continuously from gestational day 13 through postpartal day 28. By contrast, only 11% of the testes failed to descend when blocked by 5 alpha-reductase inhibitors during the same period. Flutamide administration over narrower time intervals (gestational day 13-15, 16-17, or 18-19) revealed maximal interference with testicular descent after androgen inhibition during gestational days 16-17. No significant differences in testicular or epididymal weights were evident between descended and undescended testes; furthermore, no correlation was detected between the presence of epididymal abnormalities and testicular descent. These findings indicate that androgen inhibition during a brief period of embryonic development can block testicular descent. The mechanism through which this inhibition occurs remains to be elucidated.

14 CFR 23.69 - Enroute climb/descent.

Code of Federal Regulations, 2013 CFR

2013-01-01

... inoperative and its propeller in the minimum drag position; (2) The remaining engine(s) at not more than... climb/descent. (a) All engines operating. The steady gradient and rate of climb must be determined at... applicant with— (1) Not more than maximum continuous power on each engine; (2) The landing gear retracted...

14 CFR 23.69 - Enroute climb/descent.

Code of Federal Regulations, 2014 CFR

2014-01-01

... inoperative and its propeller in the minimum drag position; (2) The remaining engine(s) at not more than... climb/descent. (a) All engines operating. The steady gradient and rate of climb must be determined at... applicant with— (1) Not more than maximum continuous power on each engine; (2) The landing gear retracted...

14 CFR 23.69 - Enroute climb/descent.

Code of Federal Regulations, 2012 CFR

2012-01-01

... inoperative and its propeller in the minimum drag position; (2) The remaining engine(s) at not more than... climb/descent. (a) All engines operating. The steady gradient and rate of climb must be determined at... applicant with— (1) Not more than maximum continuous power on each engine; (2) The landing gear retracted...

14 CFR 23.69 - Enroute climb/descent.

Code of Federal Regulations, 2011 CFR

2011-01-01

... inoperative and its propeller in the minimum drag position; (2) The remaining engine(s) at not more than... climb/descent. (a) All engines operating. The steady gradient and rate of climb must be determined at... applicant with— (1) Not more than maximum continuous power on each engine; (2) The landing gear retracted...

Entry, Descent, and Landing for Human Mars Missions

NASA Technical Reports Server (NTRS)

Munk, Michelle M.; DwyerCianciolo, Alicia M.

2012-01-01

One of the most challenging aspects of a human mission to Mars is landing safely on the Martian surface. Mars has such low atmospheric density that decelerating large masses (tens of metric tons) requires methods that have not yet been demonstrated, and are not yet planned in future Mars missions. To identify the most promising options for Mars entry, descent, and landing, and to plan development of the needed technologies, NASA's Human Architecture Team (HAT) has refined candidate methods for emplacing needed elements of the human Mars exploration architecture (such as ascent vehicles and habitats) on the Mars surface. This paper explains the detailed, optimized simulations that have been developed to define the mass needed at Mars arrival to accomplish the entry, descent, and landing functions. Based on previous work, technology options for hypersonic deceleration include rigid, mid-L/D (lift-to-drag ratio) aeroshells, and inflatable aerodynamic decelerators (IADs). The hypersonic IADs, or HIADs, are about 20% less massive than the rigid vehicles, but both have their technology development challenges. For the supersonic regime, supersonic retropropulsion (SRP) is an attractive option, since a propulsive stage must be carried for terminal descent and can be ignited at higher speeds. The use of SRP eliminates the need for an additional deceleration system, but SRP is at a low Technology Readiness Level (TRL) in that the interacting plumes are not well-characterized, and their effect on vehicle stability has not been studied, to date. These architecture-level assessments have been used to define the key performance parameters and a technology development strategy for achieving the challenging mission of landing large payloads on Mars.

CTAS: Computer intelligence for air traffic control in the terminal area

NASA Technical Reports Server (NTRS)

Erzberger, Heinz

1992-01-01

A system for the automated management and control of arrival traffic, referred to as the Center-TRACON Automation System (CTAS), has been designed by the ATC research group at NASA Ames research center. In a cooperative program, NASA and the FAA have efforts underway to install and evaluate the system at the Denver and Dallas/Ft. Worth airports. CTAS consists of three types of integrated tools that provide computer-generated intelligence for both Center and TRACON controllers to guide them in managing and controlling arrival traffic efficiently. One tool, the Traffic Management Advisor (TMA), establishes optimized landing sequences and landing times for aircraft arriving in the center airspace several hundred miles from the airport. In TRACON, TMA frequencies missed approach aircraft and unanticipated arrivals. Another tool, the Descent Advisor (DA), generates clearances for the center controllers handling at crossing times provided by TMA. In the TRACON, the final approach spacing tool (FAST) provides heading and speed clearances that produce and accurately spaced flow of aircraft on the final approach course. A data base consisting of aircraft performance models, airline preferred operational procedures and real time wind measurements contribute to the effective operation of CTAS. Extensive simulator evaluations of CTAS have demonstrated controller acceptance, delay reductions, and fuel savings.

Description of a novel HLA-B35 (B*3514) allele found in a Mexican family of Nahua Aztec descent.

PubMed

Vargas-Alarcon, G; Martinez-Laso, J; Granados, J; Diaz-Campos, N; Alvarez, M; Gomez-Casado, E; Alcocer-Varela, J; Arnaiz-Villena, A

1996-02-01

A new allele, HLA-B*3514, has been found in a Mexican family from Nahua descent. Its exon 2 is identical to that of B*3501 allele, but exon 3 bears a 3-base difference at codons 152 and 156, which results in Val-->Glu and Leu-->Trp changes, respectively, in the corresponding HLA molecule at the peptide-binding site. These substitutions may have originated from a DNA stretch donation from an allele belonging to the B15 group, enabling HLA-B*3514 to cope with the presentation of a new set of antigenic peptides. The high frequency of serologic B35 in Amerindians, together with the variety of B35 alleles detected by DNA sequencing in these populations, suggest that a frequent B35 subtype was present in the founder population and that several B35 subtypes may have been recently generated, probably due to the abrupt arrival of new pathogens following European invasions.

KSC-2011-7082

NASA Image and Video Library

2011-09-23

CAPE CANAVERAL, Fla. – At the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida, technicians carefully monitor the attachment of an overhead crane to a rocket-powered descent stage which will be integrated with NASA's Mars Science Laboratory (MSL) rover, known as Curiosity (in the foreground). The descent stage will lower Curiosity to the surface of Mars. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. Curiosity’s 10 science instruments are designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release its gasses so that the rover’s spectrometer can analyze and send the data back to Earth. MSL is scheduled to launch Nov. 25 with a window extending to Dec. 18 and arrival at Mars Aug. 2012. For more information, visit http://www.nasa.gov/msl. Photo credit: NASA/Kim Shiflett

A Revised Trajectory Algorithm to Support En Route and Terminal Area Self-Spacing Concepts

NASA Technical Reports Server (NTRS)

Abbott, Terence S.

2010-01-01

This document describes an algorithm for the generation of a four dimensional trajectory. Input data for this algorithm are similar to an augmented Standard Terminal Arrival (STAR) with the augmentation in the form of altitude or speed crossing restrictions at waypoints on the route. This version of the algorithm accommodates descent Mach values that are different from the cruise Mach values. Wind data at each waypoint are also inputs into this algorithm. The algorithm calculates the altitude, speed, along path distance, and along path time for each waypoint.

Evaluation of the Terminal Sequencing and Spacing System for Performance Based Navigation Arrivals

NASA Technical Reports Server (NTRS)

Thipphavong, Jane; Jung, Jaewoo; Swenson, Harry N.; Martin, Lynne; Lin, Melody; Nguyen, Jimmy

2013-01-01

NASA has developed the Terminal Sequencing and Spacing (TSS) system, a suite of advanced arrival management technologies combining timebased scheduling and controller precision spacing tools. TSS is a ground-based controller automation tool that facilitates sequencing and merging arrivals that have both current standard ATC routes and terminal Performance-Based Navigation (PBN) routes, especially during highly congested demand periods. In collaboration with the FAA and MITRE's Center for Advanced Aviation System Development (CAASD), TSS system performance was evaluated in human-in-the-loop (HITL) simulations with currently active controllers as participants. Traffic scenarios had mixed Area Navigation (RNAV) and Required Navigation Performance (RNP) equipage, where the more advanced RNP-equipped aircraft had preferential treatment with a shorter approach option. Simulation results indicate the TSS system achieved benefits by enabling PBN, while maintaining high throughput rates-10% above baseline demand levels. Flight path predictability improved, where path deviation was reduced by 2 NM on average and variance in the downwind leg length was 75% less. Arrivals flew more fuel-efficient descents for longer, spending an average of 39 seconds less in step-down level altitude segments. Self-reported controller workload was reduced, with statistically significant differences at the p less than 0.01 level. The RNP-equipped arrivals were also able to more frequently capitalize on the benefits of being "Best-Equipped, Best- Served" (BEBS), where less vectoring was needed and nearly all RNP approaches were conducted without interruption.

Aircraft disinsection.

PubMed

Rayman, Russell B

2006-07-01

Aircraft disinsection has been an international practice since the 1920s, the purpose of which is to protect public health, the environment, agriculture, and livestock by the eradication of disease vectors. Although most nations of the world have discontinued this practice, about 20 continue with this requirement. Aircraft disinsection is sanctioned by international law with the World Health Organization (WHO) publishing general procedural guidelines in the International Health Regulations (IHR). There are currently four acceptable procedures: blocks away, top of descent, on arrival, and residual. A 2% pyrethrum solution, a naturally occurring substance found in the chrysanthemum flower, or several synthetic pyrethroids, are the recommended agents because they are extremely effective insecticides which pose minimal health risks. Although the use of insecticides for aircraft disinsection is controversial, national policies compelling this requirement must be respected. This paper will explore the background of aircraft disinsection, the procedures, the types of agents, and the toxicity. If aircraft disinsection is regulatory policy, it should be done in accordance with WHO procedures. Residual application is probably the most efficacious method. The use of air curtains or plastic strips should be explored as an alternative to the use of chemicals.

Empirical analysis of the effect of descent flight path angle on primary gaseous emissions of commercial aircraft.

PubMed

Turgut, Enis T; Usanmaz, Oznur; Rosen, Marc A

2018-05-01

In this study, the effects of descent flight path angle (between 1.25° and 4.25°) on aircraft gaseous emissions (carbon monoxide, total hydrocarbons and nitrogen oxides) are explored using actual flight data from aircraft flight data recording system and emissions indices from the International Civil Aviation Organization. All emissions parameters are corrected to flight conditions using Boeing Fuel Flow Method2, where the ambient air pressure, temperature and humidity data are obtained from long-term radiosonde data measured close to the arrival airport. The main findings highlight that the higher the flight path angle, the higher the emission indices of CO and HC, whereas the lower the emissions index of NO x and fuel consumption. Furthermore, during a descent, a heavier aircraft tends to emit less CO and HC, and more NO x . For a five-tonne aircraft mass increase, the average change in emissions indices are found to be -4.1% and -5.7% (CO), -5.4% and -8.2% (HC), and +1.1% and +1.6% (NO x ) for high and low flight path angle groups, respectively. The average emissions indices for CO, HC and NO x during descent are calculated to be 24.5, 1.7 and 5.6 g/kg of fuel, whereas the average emissions for descending from 32,000 ft (9.7 km) and 24,000 ft (7.3 km) are calculated to be 7-8 kg (CO), ∼0.5 kg (HC) and ∼3 kg (NO x ). Copyright © 2018 Elsevier Ltd. All rights reserved.

Gradient descent learning algorithm overview: a general dynamical systems perspective.

PubMed

Baldi, P

1995-01-01

Gives a unified treatment of gradient descent learning algorithms for neural networks using a general framework of dynamical systems. This general approach organizes and simplifies all the known algorithms and results which have been originally derived for different problems (fixed point/trajectory learning), for different models (discrete/continuous), for different architectures (forward/recurrent), and using different techniques (backpropagation, variational calculus, adjoint methods, etc.). The general approach can also be applied to derive new algorithms. The author then briefly examines some of the complexity issues and limitations intrinsic to gradient descent learning. Throughout the paper, the author focuses on the problem of trajectory learning.

Entry trajectory and atmosphere reconstruction methodologies for the Mars Exploration Rover mission

NASA Astrophysics Data System (ADS)

Desai, Prasun N.; Blanchard, Robert C.; Powell, Richard W.

2004-02-01

The Mars Exploration Rover (MER) mission will land two landers on the surface of Mars, arriving in January 2004. Both landers will deliver the rovers to the surface by decelerating with the aid of an aeroshell, a supersonic parachute, retro-rockets, and air bags for safely landing on the surface. The reconstruction of the MER descent trajectory and atmosphere profile will be performed for all the phases from hypersonic flight through landing. A description of multiple methodologies for the flight reconstruction is presented from simple parameter identification methods through a statistical Kalman filter approach.

7.3 Communications and Navigation

NASA Technical Reports Server (NTRS)

Manning, Rob

2005-01-01

This presentation gives an overview of the networks NASA currently uses to support space communications and navigation, and the requirements for supporting future deep space missions, including manned lunar and Mars missions. The presentation addresses the Space Network, Deep Space Network, and Ground Network, why new support systems are needed, and the potential for catastrophic failure of aging antennas. Space communications and navigation are considered during Aerocapture, Entry, Descent and Landing (AEDL) only in order to precisely position, track and interact with the spacecraft at its destination (moon, Mars and Earth return) arrival. The presentation recommends a combined optical/radio frequency strategy for deep space communications.

The Huygens Descent Trajectory Working Group and the Reconstruction of the Huygens Probe Entry and Descent Trajectory at Titan

NASA Astrophysics Data System (ADS)

Atkinson, David H.; Kazeminejad, Bobby; Lebreton, Jean-Pierre

2015-04-01

Cassini/Huygens, a flagship mission to explore the rings, atmosphere, magnetic field, and moons that make up the Saturn system, is a joint endeavor of NASA, the European Space Agency, and Agenzia Spaziale Italiana. Comprising two spacecraft - a Saturn orbiter built by NASA and a Titan entry/descent probe built by the European Space Agency - Cassini/Huygens was launched in October 1997 and arrived at Saturn in 2004. The Huygens probe parachuted to the surface of Titan in January 2005. During the descent, six science instruments provided measurements of Titan's atmosphere, clouds, and winds, and photographed Titan's surface. It was recognized early in the Huygens program that to correctly interpret and correlate results from the probe science experiments and to provide a reference set of data for ground truth calibration of the Cassini orbiter remote sensing observations, an accurate reconstruction of the probe entry and descent trajectory and surface landing location would be necessary. The Huygens Descent Trajectory Working Group (DTWG) was chartered in 1996 as a subgroup of the Huygens Science Working Team. With membership comprising representatives from all the probe engineering and instrument teams as well as representatives of industry and the Cassini and Huygens Project Scientists, the DTWG presented an organizational framework within which instrument data was shared, the entry and descent trajectory reconstruction implemented, and the trajectory reconstruction efficiently disseminated. The primary goal of the Descent Trajectory Working Group was to develop retrieval methodologies for the probe descent trajectory reconstruction from the entry interface altitude of 1270 km to the surface using navigation data, and engineering and science data acquired by the instruments on the Huygens Probe, and to provide a reconstruction of the Huygens probe trajectory from entry to the surface of Titan that is maximally consistent with all available engineering and science data sets. The official project entry and descent trajectory reconstruction effort was published by the DTWG in 2007. A revised descent trajectory was released in 2010 that accounts for updated measurements of Titan's pole coordinates derived from radar images of Titan taken during Cassini flybys after 2007. The effect of the updated pole positions on Huygens is a southward shift of the trajectory by about 0.3 degrees with a much smaller effect of less than 0.01 degree in the zonal (west to east) direction. The revised Huygens landing coordinates of 192.335 degrees West and 10.573 degrees South with longitude and latitude residuals of respectively 0.035 degrees and 0.007 degrees, respectively, are in excellent agreement with results of recent landing site investigations using visual and radar images from the Cassini VIMS instrument. Acknowledgements *J.-P.L's work was performed while at ESA/ESTEC. DA and BK would like to express appreciation to the European Space Agency's Research and Scientific Support Department for funding the Descent Trajectory Working Group. The work of the Descent Trajectory Working Group would not have been possible without the dedicated efforts of all the Huygens principal investigators and their teams, and the science and engineering data provided from each experiment team, including M. Fulchignoni and the HASI Team, H. Niemann and the GCMS Team, J. Zarnecki and the SSP Team, M. Tomasko and the DISR Team, M. Bird and the DWE Team, and G. Israel and the ACP Team. Additionally, special thanks for many years of support to D.L. Matson, R.T. Mitchell, M. Pérez-Ayúcar, O. Witasse; J. Jones, D. Roth, N. Strange on the Cassini Navigation Team at JPL; A.-M. Schipper and P. Couzin at Thales Alenia; C. Sollazzo, D. Salt, J. Wheadon and S. Standley from the Huygens Ops Team; and R. Trautner and H. Svedhem on the Radar Team at ESTEC.

Flight Test Results: CTAS Cruise/Descent Trajectory Prediction Accuracy for En route ATC Advisories

NASA Technical Reports Server (NTRS)

Green, S.; Grace, M.; Williams, D.

1999-01-01

The Center/TRACON Automation System (CTAS), under development at NASA Ames Research Center, is designed to assist controllers with the management and control of air traffic transitioning to/from congested airspace. This paper focuses on the transition from the en route environment, to high-density terminal airspace, under a time-based arrival-metering constraint. Two flight tests were conducted at the Denver Air Route Traffic Control Center (ARTCC) to study trajectory-prediction accuracy, the key to accurate Decision Support Tool advisories such as conflict detection/resolution and fuel-efficient metering conformance. In collaboration with NASA Langley Research Center, these test were part of an overall effort to research systems and procedures for the integration of CTAS and flight management systems (FMS). The Langley Transport Systems Research Vehicle Boeing 737 airplane flew a combined total of 58 cruise-arrival trajectory runs while following CTAS clearance advisories. Actual trajectories of the airplane were compared to CTAS and FMS predictions to measure trajectory-prediction accuracy and identify the primary sources of error for both. The research airplane was used to evaluate several levels of cockpit automation ranging from conventional avionics to a performance-based vertical navigation (VNAV) FMS. Trajectory prediction accuracy was analyzed with respect to both ARTCC radar tracking and GPS-based aircraft measurements. This paper presents detailed results describing the trajectory accuracy and error sources. Although differences were found in both accuracy and error sources, CTAS accuracy was comparable to the FMS in terms of both meter-fix arrival-time performance (in support of metering) and 4D-trajectory prediction (key to conflict prediction). Overall arrival time errors (mean plus standard deviation) were measured to be approximately 24 seconds during the first flight test (23 runs) and 15 seconds during the second flight test (25 runs). The major source of error during these tests was found to be the predicted winds aloft used by CTAS. Position and velocity estimates of the airplane provided to CTAS by the ATC Host radar tracker were found to be a relatively insignificant error source for the trajectory conditions evaluated. Airplane performance modeling errors within CTAS were found to not significantly affect arrival time errors when the constrained descent procedures were used. The most significant effect related to the flight guidance was observed to be the cross-track and turn-overshoot errors associated with conventional VOR guidance. Lateral navigation (LNAV) guidance significantly reduced both the cross-track and turn-overshoot error. Pilot procedures and VNAV guidance were found to significantly reduce the vertical profile errors associated with atmospheric and aircraft performance model errors.

ExoMars 2016 Status and Future Plans

NASA Astrophysics Data System (ADS)

Svedhem, Håkan; Vago, Jorge

2017-04-01

The ExoMars programme is a joint activity by the European Space Agency(ESA) and ROSCOSMOS, Russia. It consists of the ExoMars 2016 mission, launched 14 March 2016, with the Trace Gas Orbiter, TGO, and the Entry Descent and Landing Demonstrator, EDM, named Schiaparelli, and the ExoMars 2020 mission, to be launched in May 2020, carrying a lander and a rover. TGO and EDM arrived at Mars on 19 October 2016. After a nominal entry and first phase of the descent, the EDM failed at an altitude of about 4 km and fell freely to the surface, near the centre of the landing ellipse in Meridiani Planum. The communication link was maintain up until the failure and a large data set was acquired, allowing for a complete analysis of the first successful part of the mission, and an investigation of the on board anomaly leading to the failure. The TGO spacecraft was inserted into a highly elliptical 4 sol period, near equatorial, capture orbit. Two orbits in late November were dedicated to instrument calibration and initial science observations, where an excellent performance of all instruments could be confirmed. In January 2017 the orbital plane will be changed to its final inclination of 74 degrees and the period will be reduced to one Sol. Early March two orbits are scheduled for another set of instrument observations, after which a long period of aerobraking will commence. The final operational orbit, with a 2 hour period, is expected to be reached early 2018. The TGO scientific payload consists of four instruments. These are: ACS and NOMAD, both infrared spectrometers for atmospheric measurements in solar occultation mode and in nadir mode, CASSIS, a multichannel camera with stereo imaging capability, and FREND, an epithermal neutron detector for search of subsurface hydrogen. The mass of the TGO is 3700 kg, including fuel and the mass of EDM was 600 kg. The EDM was carried to Mars by the TGO and was separated three days before arrival at Mars. This presentation will cover a brief description of the 2016 mission, results from the initial phase since arrival, present status, and future activities.

Flying Schedule-Matching Descents to Explore Flight Crews' Perceptions of Their Load and Task Feasibility

NASA Technical Reports Server (NTRS)

Martin, Lynne Hazel; Sharma, Shivanjli; Lozito, Sharon; Kaneshige, John; Hayashi, Miwa; Dulchinos, Victoria

2012-01-01

Multiple studies have investigated the development and use of ground-based (controller) tools to manage and schedule traffic in future terminal airspace. No studies have investigated the impacts that such tools (and concepts) could have on the flight-deck. To begin to redress the balance, an exploratory study investigated the procedures and actions of ten Boeing-747-400 crews as they flew eight continuous descent approaches in the Los Angeles terminal airspace, with the descents being controlled using speed alone. Although the study was exploratory in nature, four variables were manipulated: speed changes, route constraints, clearance phraseology, and winds. Despite flying the same scenarios with the same events and timing, there was at least a 50 second difference in the time it took crews to fly the approaches. This variation is the product of a number of factors but highlights potential difficulties for scheduling tools that would have to accommodate this amount of natural variation in descent times. The primary focus of this paper is the potential impact of ground scheduling tools on the flight crews performance and procedures. Crews reported "moderate to low" workload, on average; however, short periods of intense and high workload were observed. The non-flying pilot often reported a higher level of workload than the flying-pilot, which may be due to their increased interaction with the Flight Management Computer, when using the aircraft automation to assist with managing the descent clearances. It is concluded that ground-side tools and automation may have a larger impact on the current-day flight-deck than was assumed and that studies investigating this impact should continue in parallel with controller support tool development.

Large Mass, Entry, Descent and Landing Sensitivity Results for Environmental, Performance, and Design Parameters

NASA Technical Reports Server (NTRS)

Shidner, Jeremy D.; Davis, Jody L.; Cianciolo, Alicia D.; Samareh, Jamshid A.; Powell, RIchard W.

2010-01-01

Landing on Mars has been a challenging task. Past NASA missions have shown resilience to increases in spacecraft mass by scaling back requirements such as landing site altitude, landing site location and arrival time. Knowledge of the partials relating requirements to mass is critical for mission designers to understand so that the project can retain margin throughout the process. Looking forward to new missions that will land 1.5 metric tons or greater, the current level of technology is insufficient, and new technologies will need to be developed. Understanding the sensitivity of these new technologies to requirements is the purpose of this paper.

Dosage-based parameters for characterization of puff dispersion results.

PubMed

Berbekar, Eva; Harms, Frank; Leitl, Bernd

2015-01-01

A set of parameters is introduced to characterize the dispersion of puff releases based on the measured dosage. These parameters are the dosage, peak concentration, arrival time, peak time, leaving time, ascent time, descent time and duration. Dimensionless numbers for the scaling of the parameters are derived from dimensional analysis. The dimensionless numbers are tested and confirmed based on a statistically representative wind tunnel dataset. The measurements were carried out in a 1:300 scale model of the Central Business District in Oklahoma City. Additionally, the effect of the release duration on the puff parameters is investigated. Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of Online Composite Mirror Descent Algorithm.

PubMed

Lei, Yunwen; Zhou, Ding-Xuan

2017-03-01

We study the convergence of the online composite mirror descent algorithm, which involves a mirror map to reflect the geometry of the data and a convex objective function consisting of a loss and a regularizer possibly inducing sparsity. Our error analysis provides convergence rates in terms of properties of the strongly convex differentiable mirror map and the objective function. For a class of objective functions with Hölder continuous gradients, the convergence rates of the excess (regularized) risk under polynomially decaying step sizes have the order [Formula: see text] after [Formula: see text] iterates. Our results improve the existing error analysis for the online composite mirror descent algorithm by avoiding averaging and removing boundedness assumptions, and they sharpen the existing convergence rates of the last iterate for online gradient descent without any boundedness assumptions. Our methodology mainly depends on a novel error decomposition in terms of an excess Bregman distance, refined analysis of self-bounding properties of the objective function, and the resulting one-step progress bounds.

Entry, Descent, and Landing Communications for the 2011 Mars Science Laboratory

NASA Technical Reports Server (NTRS)

Abilleira, Fernando; Shidner, Jeremy D.

2012-01-01

The Mars Science Laboratory (MSL), established as the most advanced rover to land on the surface of Mars to date, launched on November 26th, 2011 and arrived to the Martian Gale Crater during the night of August 5th, 2012 (PDT). MSL will investigate whether the landing region was ever suitable to support carbon-based life, and examine rocks, soil, and the atmosphere with a sophisticated suite of tools. This paper addresses the flight system requirement by which the vehicle transmitted indications of the following events using both X-band tones and UHF telemetry to allow identification of probable root causes should a mission anomaly have occurred: Heat-Rejection System (HRS) venting, completion of the cruise stage separation, turn to entry attitude, atmospheric deceleration, bank angle reversal commanded, parachute deployment, heatshield separation, radar ground acquisition, powered descent initiation, rover separation from the descent stage, and rover release. During Entry, Descent, and Landing (EDL), the flight system transmitted a UHF telemetry stream adequate to determine the state of the spacecraft (including the presence of faults) at 8 kbps initiating from cruise stage separation through at least one minute after positive indication of rover release on the surface of Mars. The flight system also transmitted X-band semaphore tones from Entry to Landing plus one minute although since MSL was occulted, as predicted, by Mars as seen from the Earth, Direct-To-Earth (DTE) communications were interrupted at approximately is approx. 5 min after Entry ( approximately 130 prior to Landing). The primary data return paths were through the Deep Space Network (DSN) for DTE and the existing Mars network of orbiting assets for UHF, which included the Mars Reconnaissance Orbiter (MRO), Mars Odyssey (ODY), and Mars Express (MEX) elements. These orbiters recorded the telemetry data stream and returned it back to Earth via the DSN. The paper also discusses the total power received during EDL and the robustness of the telecom design strategy used to ensure EDL communications coverage.

NextGen Operations in a Simulated NY Area Airspace

NASA Technical Reports Server (NTRS)

Smith, Nancy M.; Parke, Bonny; Lee, Paul; Homola, Jeff; Brasil, Connie; Buckley, Nathan; Cabrall, Chris; Chevalley, Eric; Lin, Cindy; Morey, Susan;

ExoMars: ESA's mission to search for signs of life on the red planet

NASA Astrophysics Data System (ADS)

Gardini, B.; Vago, J. L.; Baglioni, P.; Kminek, G.; Gianfiglio, G.

In the framework of its Aurora Exploration Program in 2011 the European Space Agency ESA plans to launch the ExoMars mission ExoMars will deliver two science elements to the Martian surface a Rover carrying the Pasteur scientific payload and a small fixed surface station ---the Geophysics Environment Package GEP The Rover s scientific objectives are 1 To search for signs of past and present life and 2 To characterise in the shallow subsurface the vertical distribution profile for water and geochemical composition The science goals of GEP are 1 to measure geophysics parameters necessary to understand the planet s long-term internal evolution and habitability and 2 to characterise the local environment and identify hazards to future human missions Over its planned 6-month lifetime the Rover will travel a few kilometres searching for traces of past and present signs of life It will do this by collecting and analysing samples from within surface rocks and from underground ---down to 2-m depth The very powerful combination of mobility with the capability to access locations where organic molecules might be well preserved is unique to this mission ExoMars will have the right tools to try to answer the question of whether life ever arose on the red planet The ExoMars mission contains two other elements a Carrier and a Descent Module The Carrier will bring the Descent Module to Mars and release it from the hyperbolic arrival trajectory The Descent Module s objective is to safely deploy the Rover and the GEP ---developing a robust

The distribution of genome shared identical by descent for a pair of full sibs by means of the continuous time Markov chain

NASA Astrophysics Data System (ADS)

Julie, Hongki; Pasaribu, Udjianna S.; Pancoro, Adi

2015-12-01

This paper will allow Markov Chain's application in genome shared identical by descent by two individual at full sibs model. The full sibs model was a continuous time Markov Chain with three state. In the full sibs model, we look for the cumulative distribution function of the number of sub segment which have 2 IBD haplotypes from a segment of the chromosome which the length is t Morgan and the cumulative distribution function of the number of sub segment which have at least 1 IBD haplotypes from a segment of the chromosome which the length is t Morgan. This cumulative distribution function will be developed by the moment generating function.

Flight Evaluation of Center-TRACON Automation System Trajectory Prediction Process

NASA Technical Reports Server (NTRS)

Williams, David H.; Green, Steven M.

1998-01-01

Two flight experiments (Phase 1 in October 1992 and Phase 2 in September 1994) were conducted to evaluate the accuracy of the Center-TRACON Automation System (CTAS) trajectory prediction process. The Transport Systems Research Vehicle (TSRV) Boeing 737 based at Langley Research Center flew 57 arrival trajectories that included cruise and descent segments; at the same time, descent clearance advisories from CTAS were followed. Actual trajectories of the airplane were compared with the trajectories predicted by the CTAS trajectory synthesis algorithms and airplane Flight Management System (FMS). Trajectory prediction accuracy was evaluated over several levels of cockpit automation that ranged from a conventional cockpit to performance-based FMS vertical navigation (VNAV). Error sources and their magnitudes were identified and measured from the flight data. The major source of error during these tests was found to be the predicted winds aloft used by CTAS. The most significant effect related to flight guidance was the cross-track and turn-overshoot errors associated with conventional VOR guidance. FMS lateral navigation (LNAV) guidance significantly reduced both the cross-track and turn-overshoot error. Pilot procedures and VNAV guidance were found to significantly reduce the vertical profile errors associated with atmospheric and airplane performance model errors.

21 CFR 884.2800 - Computerized Labor Monitoring System.

Code of Federal Regulations, 2014 CFR

2014-04-01

... monitoring system is a system intended to continuously measure cervical dilation and fetal head descent and... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Computerized Labor Monitoring System. 884.2800... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Monitoring...

21 CFR 884.2800 - Computerized Labor Monitoring System.

Code of Federal Regulations, 2012 CFR

2012-04-01

... monitoring system is a system intended to continuously measure cervical dilation and fetal head descent and... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Computerized Labor Monitoring System. 884.2800... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Monitoring...

21 CFR 884.2800 - Computerized Labor Monitoring System.

Code of Federal Regulations, 2013 CFR

2013-04-01

... monitoring system is a system intended to continuously measure cervical dilation and fetal head descent and... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Computerized Labor Monitoring System. 884.2800... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Monitoring...

So Happy Together

NASA Technical Reports Server (NTRS)

2008-01-01

These three images show the progression of 'stacking' the Mars Science Laboratory rover and its descent stage in one of the Jet Propulsion Laboratory's 'clean room.' In the first image, the car-size rover is in the middle of the picture with several team members surrounding it. The team members are all dressed in special head-to-toe white suits, called 'bunny suits.' One team member is holding on to a tether to guide the large insect-like descent stage down on top of the rover. The descent stage looms high in this image. The second image shows the descent stage a few feet above the rover with the team member continuing to guide the two pieces together. The final image shows the two pieces on top of each other.

Imagine taking a very long 10-month journey with someone you've just recently met! The assembly team successfully introduced the Mars Science Laboratory rover to one of its space travel partners. For the first time, it was coupled with its 'descent stage,' the part of the spacecraft that lowers the rover to the Martian surface.

Up until now, thousands of hands and minds have been making sure this pairing is a perfect fit ... on paper. The intricate parts of the rover and descent stage have all separately undergone some serious testing. Now that they're stacked together, their teams can see how they fit together in real life. With this match-making a success, the rover and descent stage will be joined with the protective case (the 'aeroshell') for more testing. But, these pieces aren't staying together forever! They'll be separated, checked, and assembled many more times before finally coming together just before launch.

High Altitude Medical Problems

PubMed Central

Hultgren, Herbert N.

1979-01-01

Increased travel to high altitude areas by mountaineers and nonclimbing tourists has emphasized the clinical problems associated with rapid ascent. Acute mountain sickness affects most sojourners at elevations above 10,000 feet. Symptoms are usually worse on the second or third day after arrival. Gradual ascent, spending one to three days at an intermediate altitude, and the use of acetazolamide (Diamox) will prevent or ameliorate symptoms in most instances. Serious and potentially fatal problems, such as high altitude pulmonary edema or cerebral edema, occur in approximately 0.5 percent to 1.0 percent of visitors to elevations above 10,000 feet—especially with heavy physical exertion on arrival, such as climbing or skiing. Early recognition, high flow oxygen therapy and prompt descent are crucially important in management. Our knowledge of the causes of these and other high altitude problems, such as retinal hemorrhage, systemic edema and pulmonary hypertension, is still incomplete. Even less is known of the effect of high altitudes on medical conditions common at sea level or on the action of commonly used drugs. ImagesFigure 2. PMID:483805

Simulation Evaluation of Controller-Managed Spacing Tools under Realistic Operational Conditions

NASA Technical Reports Server (NTRS)

Callantine, Todd J.; Hunt, Sarah M.; Prevot, Thomas

2014-01-01

Controller-Managed Spacing (CMS) tools have been developed to aid air traffic controllers in managing high volumes of arriving aircraft according to a schedule while enabling them to fly efficient descent profiles. The CMS tools are undergoing refinement in preparation for field demonstration as part of NASA's Air Traffic Management (ATM) Technology Demonstration-1 (ATD-1). System-level ATD-1 simulations have been conducted to quantify expected efficiency and capacity gains under realistic operational conditions. This paper presents simulation results with a focus on CMS-tool human factors. The results suggest experienced controllers new to the tools find them acceptable and can use them effectively in ATD-1 operations.

Three-dimensional tracking of Cuvier's beaked whales' echolocation sounds using nested hydrophone arrays.

PubMed

Gassmann, Martin; Wiggins, Sean M; Hildebrand, John A

2015-10-01

Cuvier's beaked whales (Ziphius cavirostris) were tracked using two volumetric small-aperture (∼1 m element spacing) hydrophone arrays, embedded into a large-aperture (∼1 km element spacing) seafloor hydrophone array of five nodes. This array design can reduce the minimum number of nodes that are needed to record the arrival of a strongly directional echolocation sound from 5 to 2, while providing enough time-differences of arrivals for a three-dimensional localization without depending on any additional information such as multipath arrivals. To illustrate the capabilities of this technique, six encounters of up to three Cuvier's beaked whales were tracked over a two-month recording period within an area of 20 km(2) in the Southern California Bight. Encounter periods ranged from 11 min to 33 min. Cuvier's beaked whales were found to reduce the time interval between echolocation clicks while alternating between two inter-click-interval regimes during their descent towards the seafloor. Maximum peak-to-peak source levels of 179 and 224 dB re 1 μPa @ 1 m were estimated for buzz sounds and on-axis echolocation clicks (directivity index = 30 dB), respectively. Source energy spectra of the on-axis clicks show significant frequency components between 70 and 90 kHz, in addition to their typically noted FM upsweep at 40-60 kHz.

14 CFR 27.67 - Climb: one engine inoperative.

Code of Federal Regulations, 2013 CFR

2013-01-01

.... For multiengine helicopters, the steady rate of climb (or descent), at V y (or at the speed for... and the remaining engines at either— (1) Maximum continuous power and, for helicopters for which... power for helicopters for which certification for the use of continuous OEI power is requested. (Secs...

14 CFR 27.67 - Climb: one engine inoperative.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... For multiengine helicopters, the steady rate of climb (or descent), at V y (or at the speed for... and the remaining engines at either— (1) Maximum continuous power and, for helicopters for which... power for helicopters for which certification for the use of continuous OEI power is requested. (Secs...

14 CFR 27.67 - Climb: one engine inoperative.

Code of Federal Regulations, 2010 CFR

2010-01-01

.... For multiengine helicopters, the steady rate of climb (or descent), at V y (or at the speed for... and the remaining engines at either— (1) Maximum continuous power and, for helicopters for which... power for helicopters for which certification for the use of continuous OEI power is requested. (Secs...

Challenges of the Cassini Test Bed Simulating the Saturnian Environment

NASA Technical Reports Server (NTRS)

Hernandez, Juan C.; Badaruddin, Kareem S.

2007-01-01

The Cassini-Huygens mission is a joint NASA and European Space Agency (ESA) mission to collect scientific data of the Saturnian system and is managed by the Jet Propulsion Laboratory (JPL). After having arrived in Saturn orbit and releasing the ESA's Huygens probe for a highly successful descent and landing mission on Saturn's moon Titan, the Cassini orbiter continues on its tour of Saturn, its satellites, and the Saturnian environment. JPL's Cassini Integrated Test laboratory (ITL) is a dedicated high fidelity test bed that verifies and validates command sequences and flight software before upload to the Cassini spacecraft. The ITL provides artificial stimuli that allow a highly accurate hardware-in-the-loop test bed model that tests the operation of the Cassini spacecraft on the ground. This enables accurate prediction and recreation of mission events and flight software and hardware behavior. As we discovered more about the Saturnian environment, a combination of creative test methods and simulation changes were necessary to simulate the harmful effect that the optical and physical environment has on the pointing performance of Cassini. This paper presents the challenges experienced and overcome in that endeavor to simulate and test the post Saturn Orbit Insertion (SOI) and Probe Relay tour phase of the Cassini mission.

Science objectives of ESA's ExoMars mission

NASA Astrophysics Data System (ADS)

Vago, J. L.; Gardini, B.; Baglioni, P.; Kminek, G.; Gianfiglio, G.; Exomars Project Team

ExoMars will deliver two science elements to the Martian surface: a Rover, carrying the Pasteur scientific payload; and a small, fixed surface station -the Geophysics & Environment Package (GEP). The ExoMars mission's scientific objectives are: 1) To search for signs of past and present life on Mars; 2) To characterise the water/geochemical environment as a function of depth in the shallow subsurface; 3) To study the surface environment and identify hazards to future human missions; and 4) To investigate the planet's deep interior to better understand Mars's evolution and habitability. Over its planned 6-month lifetime, the Rover will travel a few kilometres searching for traces of past and present signs of life. It will do this by collecting and analysing samples from within surface rocks, and from underground -down to 2-m depth. The very powerful combination of mobility with the capability to access locations where organic molecules may be well preserved is unique to this mission. The ExoMars mission contains two other elements: a Carrier and a Descent Module. The Carrier will bring the Descent Module to Mars and release it from the hyperbolic arrival trajectory. The Descent Module's objective is to safely deploy the Pasteur Rover and the GEP -developing a robust European Entry, Descent and Landing System (EDLS) is another fundamental goal of this mission. The mission's data relay capability will be provided by a NASA orbiter. The Pasteur Rover's mass is presently estimated at 190 kg, including the Pasteur scientific payload. The Pasteur payload contains: Panoramic Instruments: stereoscopic cameras, a ground-penetrating radar, and an IR spectrometer; Contact Instrument for studying surface rocks: a close-up imager and a Mössbauer spectrometer; a subsurface drill capable of reaching a depth of 2 m, and also of collecting specimens from exposed bedrock; a sample preparation and distribution unit; a microscope; an oxidation sensor; and a variety of analytical instruments for the characterisation of organic substances and geochemistry in the collected samples. Latitudinal bands between -15 deg and 45 deg can be targeted for landing, ensuring that the mission is flexible enough to accommodate interesting new sites based on latest available data from on-going Mars orbital missions.

Distributed Method to Optimal Profile Descent

NASA Astrophysics Data System (ADS)

Kim, Geun I.

Current ground automation tools for Optimal Profile Descent (OPD) procedures utilize path stretching and speed profile change to maintain proper merging and spacing requirements at high traffic terminal area. However, low predictability of aircraft's vertical profile and path deviation during decent add uncertainty to computing estimated time of arrival, a key information that enables the ground control center to manage airspace traffic effectively. This paper uses an OPD procedure that is based on a constant flight path angle to increase the predictability of the vertical profile and defines an OPD optimization problem that uses both path stretching and speed profile change while largely maintaining the original OPD procedure. This problem minimizes the cumulative cost of performing OPD procedures for a group of aircraft by assigning a time cost function to each aircraft and a separation cost function to a pair of aircraft. The OPD optimization problem is then solved in a decentralized manner using dual decomposition techniques under inter-aircraft ADS-B mechanism. This method divides the optimization problem into more manageable sub-problems which are then distributed to the group of aircraft. Each aircraft solves its assigned sub-problem and communicate the solutions to other aircraft in an iterative process until an optimal solution is achieved thus decentralizing the computation of the optimization problem.

Sealing scientific probes against deep space and the Venusian environment A tough job

NASA Technical Reports Server (NTRS)

Pokras, J.; Reinert, R. P.; Switz, R. J.

1978-01-01

The Pioneer Venus mission evolved from studies conducted during the late 1960s and early 1970s. It was found that a need existed for low cost orbiters and landers to explore the planet. The considered mission was to be accomplished with six separate vehicles arriving at Venus nearly simultaneously in mid-December 1978. The probes are designed to survive entry and descent into the atmosphere. A description is presented of the approaches used to maintain sealing integrity for the large and small probes under the constraints imposed by the harsh Venusian environment. Attention is given to probe vehicle configuration, pressure vessel sealing requirements, material and configuration considerations, permanent seals, separable seals, development problems, and aspects of seal testing.

Resolving Off-Nominal Situations in Schedule-Based Terminal Area Operations: Results from a Human-in-the-Loop Simulation

NASA Technical Reports Server (NTRS)

Mercer, Joey; Callantine, Todd; Martin, Lynne

2012-01-01

A recent human-in-the-loop simulation in the Airspace Operations Laboratory (AOL) at NASA's Ames Research Center investigated the robustness of Controller-Managed Spacing (CMS) operations. CMS refers to AOL-developed controller tools and procedures for enabling arrivals to conduct efficient Optimized Profile Descents with sustained high throughput. The simulation provided a rich data set for examining how a traffic management supervisor and terminal-area controller participants used the CMS tools and coordinated to respond to off-nominal events. This paper proposes quantitative measures for characterizing the participants responses. Case studies of go-around events, replicated during the simulation, provide insights into the strategies employed and the role the CMS tools played in supporting them.

Space Science

NASA Image and Video Library

1996-12-04

The Mars Pathfinder began the journey to Mars with liftoff atop a Delta II expendable launch vehicle from launch Complex 17B on Cape Canaveral Air Station. The Mars Pathfinder traveled on a direct trajectory to Mars, and arrived there in July 1997. Mars Pathfinder sent a lander and small robotic rover, Sojourner, to the surface of Mars. The primary objective of the mission was to demonstrate a low-cost way of delivering a science package to the surface of Mars using a direct entry, descent and landing with the aid of small rocket engines, a parachute, airbags and other techniques. In addition, landers and rovers of the future will share the heritage of Mars Pathfinder designs and technologies first tested in this mission. Pathfinder also collected invaluable data about the Martian surface.

7 CFR 319.75-6 - Arrival notification.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 5 2011-01-01 2011-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6 Arrival...

7 CFR 319.75-6 - Arrival notification.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 5 2014-01-01 2014-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6 Arrival...

7 CFR 319.75-6 - Arrival notification.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 5 2013-01-01 2013-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6 Arrival...

7 CFR 319.75-6 - Arrival notification.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 5 2012-01-01 2012-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6 Arrival...

A comparison of discrete versus continuous adjoint states to invert groundwater flow in heterogeneous dual porosity systems

NASA Astrophysics Data System (ADS)

Delay, Frederick; Badri, Hamid; Fahs, Marwan; Ackerer, Philippe

2017-12-01

Dual porosity models become increasingly used for simulating groundwater flow at the large scale in fractured porous media. In this context, model inversions with the aim of retrieving the system heterogeneity are frequently faced with huge parameterizations for which descent methods of inversion with the assistance of adjoint state calculations are well suited. We compare the performance of discrete and continuous forms of adjoint states associated with the flow equations in a dual porosity system. The discrete form inherits from previous works by some of the authors, as the continuous form is completely new and here fully differentiated for handling all types of model parameters. Adjoint states assist descent methods by calculating the gradient components of the objective function, these being a key to good convergence of inverse solutions. Our comparison on the basis of synthetic exercises show that both discrete and continuous adjoint states can provide very similar solutions close to reference. For highly heterogeneous systems, the calculation grid of the continuous form cannot be too coarse, otherwise the method may show lack of convergence. This notwithstanding, the continuous adjoint state is the most versatile form as its non-intrusive character allows for plugging an inversion toolbox quasi-independent from the code employed for solving the forward problem.

7 CFR 319.75-6 - Arrival notification.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Plant Protection and Quarantine of the arrival by such means as a manifest, Customs entry document... 7 Agriculture 5 2010-01-01 2010-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION...

Models for estimating runway landing capacity with Microwave Landing System (MLS)

NASA Technical Reports Server (NTRS)

Tosic, V.; Horonjeff, R.

1975-01-01

A model is developed which is capable of computing the ultimate landing runway capacity, under ILS and MLS conditions, when aircraft population characteristics and air traffic control separation rules are given. This model can be applied in situations when only a horizontal separation between aircraft approaching a runway is allowed, as well as when both vertical and horizontal separations are possible. It is assumed that the system is free of errors, that is that aircraft arrive at specified points along the prescribed flight path precisely when the controllers intend for them to arrive at these points. Although in the real world there is no such thing as an error-free system, the assumption is adequate for a qualitative comparison of MLS with ILS. Results suggest that an increase in runway landing capacity, caused by introducing the MLS multiple approach paths, is to be expected only when an aircraft population consists of aircraft with significantly differing approach speeds and particularly in situations when vertical separation can be applied. Vertical separation can only be applied if one of the types of aircraft in the mix has a very steep descent angle.

Steps Towards the Integration of Conflict Resolution with Metering and Scheduling

NASA Technical Reports Server (NTRS)

McNally, B. David; Edwards, Thomas (Technical Monitor)

1998-01-01

NASA Ames Research Center is developing decision support tool technology for air traffic controllers to improve the efficiency and capacity of National Airspace System. The goal is to provide technology, tools and procedures that result in the highest possible level of user preferred trajectories whenever possible with safe and efficient traffic management when necessary. The work is being conducted under the NASA Advanced Air Transportation Technology Program in cooperation with the FAA through the Inter-Agency Integrated Product Team. The objective is to develop technology and procedures that lead towards a seamless integration of conflict resolution with metering and scheduling for arrival aircraft and en route aircraft that are under metering restrictions. A requirement is that the integration incorporate user preferred trajectories. The ultimate goal is the implementation and validation of the Descent Advisor (DA) concept which provides clearance advisories to a sector controller that simultaneously meet metering constraints, are conflict free, incorporate a user preferred (e.g., minimum fuel) descent profile, and generally require no further corrective clearance as the aircraft transitions from en route cruise into the TRACON. The DA concept may also be applied to en route aircraft under metering constraints, e.g., miles-in-trail. To achieve the DA concept a stepwise development and field evaluation is anticipated. This paper addresses the initial steps towards implementation of the DA. The Traffic Management Advisor (TMA) computes arrival time sequence and required delay information for display to the sector controller during periods when arrivals must be metered due to landing rate restrictions at the airport. The Initial Conflict Probe (ICP) compares trajectory predictions for all aircraft and alerts the controller when any two aircraft are predicted to violate separation standards (5 mi. and 2000 ft. in en route airspace). ICP also includes a trial planning function allowing the controller to develop and check a separate "what if" trajectory for conflict resolution. TMA and ICP currently operate independent of one another and have separate controller displays. The TMA meter list is on the radar controller's plan view display. The ICP is still under development, but the current concept calls for a list of predicted conflicts at the data controller position. The research described herein address two steps towards the implementation of DA. The first is to develop a concept for integrated display of conflict and metering information on a controller's display. The objective is to provide the controller with situational awareness of one problem while he develops a solution to the other. The next step is to expand the concept for display of automated clearance advisories for one problem (e.g., metering) which take into account the other problems (e.g., conflicts). Information to be communicated between TMA and ICP to facilitate' manual or automated advisories is being identified as the concept matures. In order to study the ICP/TMA integration concept the CTAS conflict probe capability has been adapted to Ft. Worth Center. The system is being validated in the laboratory with all-track data and for non -interference with TMA, TMA is already running as a daily use prototype at Ft. Worth Center. A laboratory prototype system has been developed under the CTAS baseline which combines conflict and metering information on a common user interface. Elements of the user interface are shown in Figure 1. In this simple illustration the user sees the simultaneous effect of a trial plan on meter fix delay and conflict status. Delay information is shown in the aircraft flight data block, the meter list, and the TMA timeline. Experience during Descent Advisor development and observations at Ft. Worth Center high and low attitude arrival sectors during metering suggests that manual trial planning will be unworkable during rush periods due to high controller workload.

7 CFR 319.8-4 - Notice of arrival.

Code of Federal Regulations, 2010 CFR

2010-01-01

... for the Plant Protection and Quarantine Programs, a notice of such arrival, on a form provided for... 7 Agriculture 5 2010-01-01 2010-01-01 false Notice of arrival. 319.8-4 Section 319.8-4 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE...

A Rocket Investigation of Mesospheric Eddy Diffusion Effects on Airglow and Oxygen Chemistry

NASA Technical Reports Server (NTRS)

Ulwick, James C.

2001-01-01

A Terrier Orion rocket was launched at 0750 Z on 02/25/98 about seven minutes after the Clemson University chemical release rocket. Measurements made of the electron density by a dc probe calibrated by a capacitance probe showed several layers of electron density on a rocket ascent in the altitude range from 90 to 110 km. Rocket descent results showed several but not all of the ascent structure. From power spectral analysis of the measured electron densities, turbulent parameters are derived Measurements were made on rocket ascent and descent by an infrared radiometer of the OH Meinel (3-1) band and O2 singlet delta emissions. Profiles of the emissions are presented and discussed on both rocket ascent and descent an enhancement of the OH emission monitored by the OH radiometer was observed above 90 km. The glow was not defected by the O2 radiometer and was significantly reduced on rocket descent. Using these data and a mechanistic analysis, a profile proportional to atomic oxygen is obtained. This profile is compared to one from the ATOX probe on the rocket. A one-dimensional (1-D) photochemical model that solves the time-dependent continuity equations is used with the rocket data to investigate the odd-oxygen concentration in the near equatorial mesosphere.

Pegasus XL CYGNSS Arrival at CCAFS

NASA Image and Video Library

2016-12-02

The Orbital ATK L-1011 Stargazer aircraft begins its descent to the Skid Strip at Cape Canaveral Air Force Station in Florida. Attached beneath the Stargazer is the Orbital ATK Pegasus XL with NASA's Cyclone Global Navigation Satellite System (CYGNSS) on board. CYGNSS was processed and prepared for its mission at Vandenberg Air Force Base in California. CYGNSS is scheduled for its airborne launch aboard the Pegasus XL rocket from the Skid Strip on Dec. 12. CYGNSS will make frequent and accurate measurements of ocean surface winds throughout the life cycle of tropical storms and hurricanes. The data that CYGNSS provides will enable scientists to probe key air-sea interaction processes that take place near the core of storms, which are rapidly changing and play a critical role in the beginning and intensification of hurricanes.

Assessment of environments for Mars Science Laboratory entry, descent, and surface operations

USGS Publications Warehouse

Vasavada, Ashwin R.; Chen, Allen; Barnes, Jeffrey R.; Burkhart, P. Daniel; Cantor, Bruce A.; Dwyer-Cianciolo, Alicia M.; Fergason, Robini L.; Hinson, David P.; Justh, Hilary L.; Kass, David M.; Lewis, Stephen R.; Mischna, Michael A.; Murphy, James R.; Rafkin, Scot C.R.; Tyler, Daniel; Withers, Paul G.

2012-01-01

The Mars Science Laboratory mission aims to land a car-sized rover on Mars' surface and operate it for at least one Mars year in order to assess whether its field area was ever capable of supporting microbial life. Here we describe the approach used to identify, characterize, and assess environmental risks to the landing and rover surface operations. Novel entry, descent, and landing approaches will be used to accurately deliver the 900-kg rover, including the ability to sense and "fly out" deviations from a best-estimate atmospheric state. A joint engineering and science team developed methods to estimate the range of potential atmospheric states at the time of arrival and to quantitatively assess the spacecraft's performance and risk given its particular sensitivities to atmospheric conditions. Numerical models are used to calculate the atmospheric parameters, with observations used to define model cases, tune model parameters, and validate results. This joint program has resulted in a spacecraft capable of accessing, with minimal risk, the four finalist sites chosen for their scientific merit. The capability to operate the landed rover over the latitude range of candidate landing sites, and for all seasons, was verified against an analysis of surface environmental conditions described here. These results, from orbital and model data sets, also drive engineering simulations of the rover's thermal state that are used to plan surface operations.

Huygens Highlights and lessons learned

NASA Astrophysics Data System (ADS)

Lebreton, Jean-Pierre

2015-04-01

Ten years ago, on 14 January 2005, the Huygens Probe parachuted down to the surface of Titan, Saturn's largest moon. Huygens is part of the international Cassini/Huygens mission, a joint endeavor of NASA, the European Space Agency, and Agenzia Spaziale Italiana. Cassini/Huygens, comprising the NASA-provided Saturn Orbiter and the ESA-provided Huygens probe, was launched in October 1997. It arrived at Saturn in early July 2004. Huygens was released on the 3rd orbit around Saturn. It made measurements during the hypersonic entry, the descent, and for more than one hour on the surface. Unique in situ characterization of the atmosphere along the entry and descent trajectory and of the surface at the landing site was provided, revealing that many Earth-like processes were at work on Titan, a very fascinating methane world. Huygens observations also allowed inferring the ice crust thickness, hence an estimation of the depth of the icy crust/liquid water ocean interface. Huygens measurements are also used as ground-truth of the measurements made by the orbiter during Titan flybys. In this presentation, after a brief review of the major mission milestones, Huygens achievements are discussed in the context of the progress made in our understanding of Titan during the Cassini/Huygens mission. Lessons learned for the future in situ exploration of Titan are addressed. * Most of this work was performed while at ESA/ESTEC, Noordwijk, The Netherlands

33 CFR 146.202 - Notice of arrival or relocation of MODUs on the OCS.

Code of Federal Regulations, 2010 CFR

2010-07-01

... OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES OPERATIONS Mobile Offshore Drilling Units § 146.202 Notice of arrival or relocation of MODUs on the OCS. (a) The owner of any mobile offshore drilling unit engaged in OCS activities shall, 14 days before arrival of the unit on the OCS or as...

A conjugate gradient method with descent properties under strong Wolfe line search

NASA Astrophysics Data System (ADS)

Zull, N.; ‘Aini, N.; Shoid, S.; Ghani, N. H. A.; Mohamed, N. S.; Rivaie, M.; Mamat, M.

2017-09-01

The conjugate gradient (CG) method is one of the optimization methods that are often used in practical applications. The continuous and numerous studies conducted on the CG method have led to vast improvements in its convergence properties and efficiency. In this paper, a new CG method possessing the sufficient descent and global convergence properties is proposed. The efficiency of the new CG algorithm relative to the existing CG methods is evaluated by testing them all on a set of test functions using MATLAB. The tests are measured in terms of iteration numbers and CPU time under strong Wolfe line search. Overall, this new method performs efficiently and comparable to the other famous methods.

CryoScout: A Descent Through the Mars Polar Cap

NASA Technical Reports Server (NTRS)

Hecht, M. H.; Saunders, R. S.

2003-01-01

CryoScout was proposed as a subsurface investigation of the stratigraphic climate record embedded in Mars North Polar cap. After landing on a gentle landscape in the midst of the mild summer season, CryoScout was to use the continuous polar sunlight to power the descent of a cryobot, a thermal probe, into the ice at a rate of about 1 m per day. CryoScout would probe deep enough into this time capsule to see the effects of planetary obliquity variations and discrete events such as dust storms or volcanic eruptions. By penetrating tens of meters of ice, the mission would explore at least one of the dominant "MOC layers" observed in exposed layered terrain.

Probability of identity by descent in metapopulations.

PubMed Central

Kaj, I; Lascoux, M

1999-01-01

Equilibrium probabilities of identity by descent (IBD), for pairs of genes within individuals, for genes between individuals within subpopulations, and for genes between subpopulations are calculated in metapopulation models with fixed or varying colony sizes. A continuous-time analog to the Moran model was used in either case. For fixed-colony size both propagule and migrant pool models were considered. The varying population size model is based on a birth-death-immigration (BDI) process, to which migration between colonies is added. Wright's F statistics are calculated and compared to previous results. Adding between-island migration to the BDI model can have an important effect on the equilibrium probabilities of IBD and on Wright's index. PMID:10388835

A GNM mission and system design proposal

NASA Technical Reports Server (NTRS)

Bailey, Stephen

1990-01-01

Here, the author takes an advocacy position for the proposed Mars Global Network Mission (GNM); it is not intended to be an objective review, although both pros and cons are presented in summary. The mission consists of launches from earth in the '96, '98, and '01 opportunities on Delta-class launch vehicles (approx. 1000 kg injected to Mars in 8 to 10 ft diameter shroud). The trans Mars boost stage injects a stack of small independent, aeroshelled spacecraft. The stack separates from the boost stage and each rigid (as opposed to deployable) aeroshell flies to Mars on its own, performing midcourse maneuvers as necessary. Each spacecraft flies a unique trajectory which is targeted to achieve approach atmospheric interface at the desired latitude and lighting conditions; arrival times may vary by a month or more. A direct entry is performed, there is no propulsive orbit capture. The aeroshelled rough-landers are targeted to achieve a desired attitude and entry flight path angle, and then follow a passive ballistic trajectory until terminal descent. Based on sensed acceleration (integrated to deduce altitude), the aft aeroshell skirt is jettisoned; a short later a supersonic parachute is deployed. The ballistic coefficient of the parachute is sized to achieve terminal velocity at about 8 km. However the parachute is not deployed until a few Km above the surface to minimize wind-induced drift. The nose cap descent imaging begins, a laser altimeter also measures true altitude. Based on range and range rate to the surface, the parachute is jettisoned and the lander uses descent engines to achieve touchdown velocity. A contact sensor shuts down the motors to avoid cratering, and the lander rough-lands at less than 5 m/sec. The remaining aeroshell and a deployable bladder attenuate landing loads and minimize the possibility of tip over. Science instruments are deployed and activated, and the network is established.

Rebuilding Iraq - The Danish Interagency Strategy

DTIC Science & Technology

2007-02-09

HDI ), Iraq dropped from position number 76 in 1990, to position 126 in 2000. No other country underwent a similar descent in the same period. In the...and mutually impressionable main tendencies in Iraq today: progress in the political process, endeavors to rebuild the country , and a continued...the country , and (3) a continued serious security situation including violent incidents especially in the central part of Iraq but also in other

Calculation of Flight Deck Interval Management Assigned Spacing Goals Subject to Multiple Scheduling Constraints

NASA Technical Reports Server (NTRS)

Robinson, John E.

2014-01-01

The Federal Aviation Administration's Next Generation Air Transportation System will combine advanced air traffic management technologies, performance-based procedures, and state-of-the-art avionics to maintain efficient operations throughout the entire arrival phase of flight. Flight deck Interval Management (FIM) operations are expected to use sophisticated airborne spacing capabilities to meet precise in-trail spacing from top-of-descent to touchdown. Recent human-in-the-loop simulations by the National Aeronautics and Space Administration have found that selection of the assigned spacing goal using the runway schedule can lead to premature interruptions of the FIM operation during periods of high traffic demand. This study compares three methods for calculating the assigned spacing goal for a FIM operation that is also subject to time-based metering constraints. The particular paradigms investigated include: one based upon the desired runway spacing interval, one based upon the desired meter fix spacing interval, and a composite method that combines both intervals. These three paradigms are evaluated for the primary arrival procedures to Phoenix Sky Harbor International Airport using the entire set of Rapid Update Cycle wind forecasts from 2011. For typical meter fix and runway spacing intervals, the runway- and meter fix-based paradigms exhibit moderate FIM interruption rates due to their inability to consider multiple metering constraints. The addition of larger separation buffers decreases the FIM interruption rate but also significantly reduces the achievable runway throughput. The composite paradigm causes no FIM interruptions, and maintains higher runway throughput more often than the other paradigms. A key implication of the results with respect to time-based metering is that FIM operations using a single assigned spacing goal will not allow reduction of the arrival schedule's excess spacing buffer. Alternative solutions for conducting the FIM operation in a manner more compatible with the arrival schedule are discussed in detail.

Mars Phoenix Entry, Descent, and Landing Simulation Design and Modelling Analysis

NASA Technical Reports Server (NTRS)

Prince, Jill L.; Desai, Prasun N.; Queen, Eric M.; Grover, Myron R.

2008-01-01

The 2007 Mars Phoenix Lander was launched in August of 2007 on a ten month cruise to reach the northern plains of Mars in May 2008. Its mission continues NASA s pursuit to find evidence of water on Mars. Phoenix carries upon it a slew of science instruments to study soil and ice samples from the northern region of the planet, an area previously undiscovered by robotic landers. In order for these science instruments to be useful, it was necessary for Phoenix to perform a safe entry, descent, and landing (EDL) onto the surface of Mars. The EDL design was defined through simulation and analysis of the various phases of the descent. An overview of the simulation and various models developed to characterize the EDL performance is provided. Monte Carlo statistical analysis was performed to assess the performance and robustness of the Phoenix EDL system and are presented in this paper. Using these simulation and modelling tools throughout the design and into the operations phase, the Mars Phoenix EDL was a success on May 25, 2008.

21 CFR 884.2800 - Computerized Labor Monitoring System.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Computerized Labor Monitoring System. 884.2800... Devices § 884.2800 Computerized Labor Monitoring System. (a) Identification. A computerized labor monitoring system is a system intended to continuously measure cervical dilation and fetal head descent and...

Search for the Mars 2 Debris Field

NASA Image and Video Library

2014-10-29

NASA Mars Reconnaissance Orbiter acquired this image to aid in the search for the missing lander, Mars 2. If the debris field is found, it could serve as a future landing location to study the effects of crash landing on the Martian surface. Despite the recent successes of missions landing on Mars, like the Mars Science Laboratory (Curiosity) or the arrival of new satellites, such as India's MOM orbiter, the Red Planet is also a graveyard of failed missions. The Soviet Mars 2 lander was the first man-made object to touch the surface of the Red Planet when it crashed landed on 27 November 1971. It is believed that the descent stage malfunctioned after the lander entered the atmosphere at too steep an angle. Attempts to contact the probe after the crash were unsuccessful. http://photojournal.jpl.nasa.gov/catalog/PIA18888

Flight Reconstruction of the Mars Pathfinder Disk-Gap-Band Parachute Drag Coefficient

NASA Technical Reports Server (NTRS)

Desai, Prasun; Schofield, John T.; Lisano, Michael E.

2003-01-01

On July 4, 1997, the Mars Pathfinder (MPF) mission successfully landed on Mars. The entry, descent, and landing (EDL) scenario employed the use of a Disk-Gap-Band parachute design to decelerate the Lander. Flight reconstruction of the entry using MPF flight accelerometer data revealed that the MPF parachute decelerated faster than predicted. In the summer of 2003, the Mars Exploration Rover (MER) mission will send two Landers to the surface of Mars arriving in January 2004. The MER mission utilizes a similar EDL scenario and parachute design as that employed by MPF. As a result, characterizing the degree of underperformance of the MPF parachute system is critical for the MER EDL trajectory design. This paper provides an overview of the methodology utilized to estimate the MPF parachute drag coefficient as experienced on Mars.

Part I: Houtermans

NASA Astrophysics Data System (ADS)

Frenkel, Victor Ya.

The following sections are included: * PROFESSOR FRIEDRICH HOUTERMANS: WORKS, LIFE, FATE * Introduction * Beginnings * Göttingen * Berlin * 1933 * London * Impressions of Kharkov * Kharkov: 1935-1937 * Arrests * Last Months in the USSR (From Charlotte Houtermans' Diary) * Descent into the Prisons: 1937-39 * From Desperation to Hope (Continuation of Charlotte Houtermans' Diary) * Fighting for Freedom * Descent into the Prisons: 1939-40 * The Bridge over the River Bug * On the Other Shore * Back in Berlin * The Plutonium Report * "They should Accelerate!" * Back in Kharkov * Kharkov Trace (What Happened at the Session of the Academy of Sciences) * Who are Beck and Godin? * War's End * The Age of the Earth * Friends on Houtermans * Chronology * Appendices (Compiled by the Editor) * Last Diary * Odessa 1930 * Chronological Report of my Life in Russian Prisons * Alexander Weissberg's Letter * After the War

14 CFR 29.1045 - Climb cooling test procedures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... engines and powerplant components. (c) Each operating engine must— (1) For helicopters for which the use... continuous power (or at full throttle when above the critical altitude); (2) For helicopters for which the... one engine operative; and (2) Sea level. (f) The climb or descent must be conducted at an airspeed...

14 CFR 29.1045 - Climb cooling test procedures.

Code of Federal Regulations, 2012 CFR

2012-01-01

... engines and powerplant components. (c) Each operating engine must— (1) For helicopters for which the use... continuous power (or at full throttle when above the critical altitude); (2) For helicopters for which the... one engine operative; and (2) Sea level. (f) The climb or descent must be conducted at an airspeed...

14 CFR 29.1045 - Climb cooling test procedures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... engines and powerplant components. (c) Each operating engine must— (1) For helicopters for which the use... continuous power (or at full throttle when above the critical altitude); (2) For helicopters for which the... one engine operative; and (2) Sea level. (f) The climb or descent must be conducted at an airspeed...

Continuous time-of-flight ion mass spectrometer

DOEpatents

Funsten, Herbert O.; Feldman, William C.

2004-10-19

A continuous time-of-flight mass spectrometer having an evacuated enclosure with means for generating an electric field located in the evacuated enclosure and means for injecting a sample material into the electric field. A source of continuous ionizing radiation injects ionizing radiation into the electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between arrival of a secondary electron out of said ionized atoms or molecules at a first predetermined location and arrival of a sample ion out of said ionized atoms or molecules at a second predetermined location.

Modelling the descent of nitric oxide during the elevated stratopause event of January 2013

NASA Astrophysics Data System (ADS)

Orsolini, Yvan J.; Limpasuvan, Varavut; Pérot, Kristell; Espy, Patrick; Hibbins, Robert; Lossow, Stefan; Raaholt Larsson, Katarina; Murtagh, Donal

2017-03-01

Using simulations with a whole-atmosphere chemistry-climate model nudged by meteorological analyses, global satellite observations of nitrogen oxide (NO) and water vapour by the Sub-Millimetre Radiometer instrument (SMR), of temperature by the Microwave Limb Sounder (MLS), as well as local radar observations, this study examines the recent major stratospheric sudden warming accompanied by an elevated stratopause event (ESE) that occurred in January 2013. We examine dynamical processes during the ESE, including the role of planetary wave, gravity wave and tidal forcing on the initiation of the descent in the mesosphere-lower thermosphere (MLT) and its continuation throughout the mesosphere and stratosphere, as well as the impact of model eddy diffusion. We analyse the transport of NO and find the model underestimates the large descent of NO compared to SMR observations. We demonstrate that the discrepancy arises abruptly in the MLT region at a time when the resolved wave forcing and the planetary wave activity increase, just before the elevated stratopause reforms. The discrepancy persists despite doubling the model eddy diffusion. While the simulations reproduce an enhancement of the semi-diurnal tide following the onset of the 2013 SSW, corroborating new meteor radar observations at high northern latitudes over Trondheim (63.4°N), the modelled tidal contribution to the forcing of the mean meridional circulation and to the descent is a small portion of the resolved wave forcing, and lags it by about ten days.

Controlled weather balloon ascents and descents for atmospheric research and climate monitoring

PubMed Central

Kräuchi, Andreas; Philipona, Rolf; Romanens, Gonzague; Hurst, Dale F.; Hall, Emrys G.; Jordan, Allen F.

2017-01-01

In situ upper-air measurements are often made with instruments attached to weather balloons launched at the surface and lifted into the stratosphere. Present-day balloon-borne sensors allow near-continuous measurements from the Earth’s surface to about 35 km (3–5 hPa), where the balloons burst and their instrument payloads descend with parachutes. It has been demonstrated that ascending weather balloons can perturb the air measured by very sensitive humidity and temperature sensors trailing behind them, particularly in the upper troposphere and lower stratosphere (UTLS). The use of controlled balloon descent for such measurements has therefore been investigated and is described here. We distinguish between the single balloon technique that uses a simple automatic valve system to release helium from the balloon at a preset ambient pressure, and the double balloon technique that uses a carrier balloon to lift the payload and a parachute balloon to control the descent of instruments after the carrier balloon is released at preset altitude. The automatic valve technique has been used for several decades for water vapor soundings with frost point hygrometers, whereas the double balloon technique has recently been re-established and deployed to measure radiation and temperature profiles through the atmosphere. Double balloon soundings also strongly reduce pendulum motion of the payload, stabilizing radiation instruments during ascent. We present the flight characteristics of these two ballooning techniques and compare the quality of temperature and humidity measurements made during ascent and descent. PMID:29263765

Controlled weather balloon ascents and descents for atmospheric research and climate monitoring.

PubMed

Kräuchi, Andreas; Philipona, Rolf; Romanens, Gonzague; Hurst, Dale F; Hall, Emrys G; Jordan, Allen F

2016-01-01

In situ upper-air measurements are often made with instruments attached to weather balloons launched at the surface and lifted into the stratosphere. Present-day balloon-borne sensors allow near-continuous measurements from the Earth's surface to about 35 km (3-5 hPa), where the balloons burst and their instrument payloads descend with parachutes. It has been demonstrated that ascending weather balloons can perturb the air measured by very sensitive humidity and temperature sensors trailing behind them, particularly in the upper troposphere and lower stratosphere (UTLS). The use of controlled balloon descent for such measurements has therefore been investigated and is described here. We distinguish between the single balloon technique that uses a simple automatic valve system to release helium from the balloon at a preset ambient pressure, and the double balloon technique that uses a carrier balloon to lift the payload and a parachute balloon to control the descent of instruments after the carrier balloon is released at preset altitude. The automatic valve technique has been used for several decades for water vapor soundings with frost point hygrometers, whereas the double balloon technique has recently been re-established and deployed to measure radiation and temperature profiles through the atmosphere. Double balloon soundings also strongly reduce pendulum motion of the payload, stabilizing radiation instruments during ascent. We present the flight characteristics of these two ballooning techniques and compare the quality of temperature and humidity measurements made during ascent and descent.

Europe reaches new frontier - Huygens lands on Titan

NASA Astrophysics Data System (ADS)

2005-01-01

The first scientific data arrived at the European Space Operations Centre (ESOC) in Darmstadt, Germany, this afternoon at 17:19 CET. Huygens is mankind’s first successful attempt to land a probe on another world in the outer Solar System. “This is a great achievement for Europe and its US partners in this ambitious international endeavour to explore Saturn system,” said Jean-Jacques Dordain, ESA’s Director General. Following its release from the Cassini mothership on 25 December, Huygens reached Titan’s outer atmosphere after 20 days and a 4 million km cruise. The probe started its descent through Titan’s hazy cloud layers from an altitude of about 1270 km at 11:13 CET. During the following three minutes Huygens had to decelerate from 18 000 to 1400 km per hour. A sequence of parachutes then slowed it down to less than 300 km per hour. At a height of about 160 km the probe’s scientific instruments were exposed to Titan’s atmosphere. At about 120 km, the main parachute was replaced by a smaller one to complete the descent, with an expected touchdown at 13:34 CET. Preliminary data indicate that the probe landed safely, likely on a solid surface. The probe began transmitting data to Cassini four minutes into its descent and continued to transmit data after landing at least as long as Cassini was above Titan’s horizon. The certainty that Huygens was alive came already at 11:25 CET today, when the Green Bank radio telescope in West Virginia, USA, picked up a fain but unmistakable radio signal from the probe. Radio telescopes on Earth continued to receive this signal well past the expected lifetime of Huygens. Huygens data, relayed by Cassini, were picked up by NASA’s Deep Space Network and delivered immediately to ESA’s European Space Operation Centre in Darmstadt, Germany, where the scientific analysis is currently taking place. “Titan was always the target in the Saturn system where the need for ‘ground truth’ from a probe was critical. It is a fascinating world and we are now eagerly awaiting the scientific results,” says Professor David Southwood, Director of ESA’s scientific programmme. “The Huygens scientists are all delighted. This was worth the long wait,” says Dr Jean-Pierre Lebreton, ESA Huygens Mission Manager. Huygens is expected to provide the first direct and detailed sampling of Titan’s atmospheric chemistry and the first photographs of its hidden surface, and will supply a detailed ‘weather report’. One of the main reasons for sending Huygens to Titan is that its nitrogen atmosphere, rich in methane, and its surface may contain many chemicals of the kind that existed on the young Earth. Combined with the Cassini observations, Huygens will afford an unprecedented view of Saturn’s mysterious moon. “Descending through Titan was a once-in-a-lifetime opportunity and today’s achievement proves that our partnership with ESA was an excellent one,” says Alphonso Diaz, NASA Associate Administrator of Science. The Cassini-Huygens mission is a cooperation between NASA, the European Space Agency and ASI, the Italian space agency. The Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, is managing the mission for NASA’s Office of Space Science, Washington. JPL designed, developed and assembled the Cassini orbiter. “The teamwork in Europe and the USA, between scientists, industry and agencies has been extraordinary and has set the foundations for today’s enormous success,” concludes Jean-Jacques Dordain.

ARTIST CONCEPT - APOLLO XI - LUNAR SURFACE

NASA Image and Video Library

1969-07-11

S69-39011 (July 1969) --- TRW Incorporated's artist concept depicting the Apollo 11 Lunar Module (LM) descending to the surface of the moon. Inside the LM will be astronauts Neil A. Armstrong, commander, and Edwin E. Aldrin Jr., lunar module pilot. Astronaut Michael Collins, command module pilot, will remain with the Command and Service Modules (CSM) in lunar orbit. TRW's LM descent engine will brake Apollo 11's descent to the lunar surface. The throttle-able rocket engine will be fired continuously the last 10 miles of the journey to the moon, slowing the LM to a speed of two miles per hour at touchdown. TRW Incorporated designed and built the unique engine at Redondo Beach, California under subcontract to the Grumman Aircraft Engineering Corporation, Bethpage, New York, the LM prime contractor.

Perceptions of Care: Self Reflections of Women Teachers of African Descent Who Teach in Urban Settings

ERIC Educational Resources Information Center

Abioro, Elizabeth

2010-01-01

Discussions and debates about the educational system in the United States continue to center on curriculum and school reform. However, many children in America's public schools suffer from existing "life hazards" including social isolation, poverty, neglect, drug abuse, violence, school failure, and the breakdown of traditional family…

Concept of Operations for Interval Management Arrivals and Approach

NASA Technical Reports Server (NTRS)

Hicok, Daniel S.; Barmore, Bryan E.

2016-01-01

This paper presents the concept of operations for interval management operations to be deployed in the US National Airspace System (NAS) by the Federal Aviation Administration (FAA) Interval Management Program. The arrivals and approach operations are explored in detail including the primary operation and variations. The use of interval management operations is described that begin in en route airspace and continue to a termination point inside the arrival terminal area in the highly automated terminal environment that includes other arrival management tools such as arrival metering, Ground-based Interval Management - Spacing (GIM-S), and Terminal Sequencing and Spacing (TSAS). The roles of Air Traffic and Pilots and the ground automation tools that are used by Air Traffic Controllers to enable the operations are explored.

Development of an Interval Management Algorithm Using Ground Speed Feedback for Delayed Traffic

NASA Technical Reports Server (NTRS)

Barmore, Bryan E.; Swieringa, Kurt A.; Underwood, Matthew C.; Abbott, Terence; Leonard, Robert D.

2016-01-01

One of the goals of NextGen is to enable frequent use of Optimized Profile Descents (OPD) for aircraft, even during periods of peak traffic demand. NASA is currently testing three new technologies that enable air traffic controllers to use speed adjustments to space aircraft during arrival and approach operations. This will allow an aircraft to remain close to their OPD. During the integration of these technologies, it was discovered that, due to a lack of accurate trajectory information for the leading aircraft, Interval Management aircraft were exhibiting poor behavior. NASA's Interval Management algorithm was modified to address the impact of inaccurate trajectory information and a series of studies were performed to assess the impact of this modification. These studies show that the modification provided some improvement when the Interval Management system lacked accurate trajectory information for the leading aircraft.

Telecommunications Relay Support of the Mars Phoenix Lander Mission

NASA Technical Reports Server (NTRS)

Edwards, Charles D., Jr.; Erickson, James K.; Gladden, Roy E.; Guinn, Joseph R.; Ilott, Peter A.; Jai, Benhan; Johnston, Martin D.; Kornfeld, Richard P.; Martin-Mur, Tomas J.; McSmith, Gaylon W.;

Scientific and Technical Support for the Galileo Net Flux Radiometer Experiment

NASA Technical Reports Server (NTRS)

Sromovsky, Lawrence A.

1997-01-01

This report describes work in support of the Galileo Net Flux Radiometer (NFR), an instrument mounted on the Galileo probe, a spacecraft designed for entry into and direct measurements of Jupiter's atmosphere. Tasks originally proposed for the post launch period are briefly as follows: attend and support PSG (Project Science Group) and other project science meetings; support in-flight checkouts; maintain and keep safe the spare instrument and GSE (Ground Support Equipment); organize and maintain documentation; finish NFR calibration measurements, documentation, and analysis; characterize and diagnose instrument anomalies; develop descent data analysis tools; and science data analysis and publication. Because we had the capability to satisfy a project support need we also subsequently proposed and were funded to make ground- based observations of Jupiter during the period surrounding the Galileo arrival at Jupiter, using the Swedish Solar Telescope at La Palma, Canary Islands. The following section (11) provides background information on the NFR instrument.

Optimizing Parking Orbits for Roundtrip Mars Missions

NASA Technical Reports Server (NTRS)

Qu, Min; Merill, Raymond G.; Chai, Patrick; Komar, David R.

2017-01-01

A roundtrip Mars mission presents many challenges to the design of a transportation system and requires a series of orbital maneuvers within Mars vicinity to capture, reorient, and then return the spacecraft back to Earth. The selection of a Mars parking orbit is crucial to the mission design; not only can the parking or-bit choice drastically impact the ?V requirements of these maneuvers but also it must be properly aligned to target desired surface or orbital destinations. This paper presents a method that can optimize the Mars parking orbits given the arrival and departure conditions from heliocentric trajectories, and it can also en-force constraints on the parking orbits to satisfy other architecture design requirements such as co-planar subperiapsis descent to planned landing sites, due east or co-planar ascent back to the parking orbit, or low cost transfers to and from Phobos and Deimos.

Mars pathfinder lander deployment mechanisms

NASA Technical Reports Server (NTRS)

Gillis-Smith, Greg R.

1996-01-01

The Mars Pathfinder Lander employs numerous mechanisms, as well as autonomous mechanical functions, during its Entry, Descent and Landing (EDL) Sequence. This is the first US lander of its kind, since it is unguided and airbag-protected for hard landing using airbags, instead of retro rockets, to soft land. The arrival condition, location, and orientation of the Lander will only be known by the computer on the Lander. The Lander will then autonomously perform the appropriate sequence to retract the airbags, right itself, and open, such that the Lander is nearly level with no airbag material covering the solar cells. This function uses two different types of mechanisms - the Airbag Retraction Actuators and the Lander Petal Actuators - which are designed for the high torque, low temperature, dirty environment and for limited life application. The development of these actuators involved investigating low temperature lubrication, Electrical Discharge Machining (EDM) to cut gears, and gear design for limited life use.

An Airborne Conflict Resolution Approach Using a Genetic Algorithm

NASA Technical Reports Server (NTRS)

Mondoloni, Stephane; Conway, Sheila

2001-01-01

An airborne conflict resolution approach is presented that is capable of providing flight plans forecast to be conflict-free with both area and traffic hazards. This approach is capable of meeting constraints on the flight plan such as required times of arrival (RTA) at a fix. The conflict resolution algorithm is based upon a genetic algorithm, and can thus seek conflict-free flight plans meeting broader flight planning objectives such as minimum time, fuel or total cost. The method has been applied to conflicts occurring 6 to 25 minutes in the future in climb, cruise and descent phases of flight. The conflict resolution approach separates the detection, trajectory generation and flight rules function from the resolution algorithm. The method is capable of supporting pilot-constructed resolutions, cooperative and non-cooperative maneuvers, and also providing conflict resolution on trajectories forecast by an onboard FMC.

KSC-07pd1375

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- STS-117 Commander Frederick Sturckow and Pilot Lee Archambault aim high to begin landing practice in the shuttle training aircraft (STA). The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

Non-mechanical beam control for entry, descent and landing laser radar (Conference Presentation)

NASA Astrophysics Data System (ADS)

Stockley, Jay E.; Kluttz, Kelly; Hosting, Lance; Serati, Steve; Bradley, Cullen P.; McManamon, Paul F.; Amzajerdian, Farzin

2017-05-01

Laser radar for entry, descent, and landing (EDL) applications as well as the space docking problem could benefit from a low size, weight, and power (SWaP) beam control system. Moreover, an inertia free approach employing non-mechanical beam control is also attractive for laser radar that is intended to be employed aboard space platforms. We are investigating a non-mechanical beam steering (NMBS) sub-system based on liquid crystal polarization grating (LCPG) technology with emphasis placed on improved throughput and significant weight reduction by combining components and drastically reducing substrate thicknesses. In addition to the advantages of non-mechanical, gimbal free beam control, and greatly improved SWaP, our approach also enables wide area scanning using a scalable architecture. An extraterrestrial application entails additional environmental constraints, consequently an environmental test plan tailored to an EDL mission will also be discussed. In addition, we will present advances in continuous fine steering technology which would complement the coarse steering LCPG technology. A low-SWaP, non-mechanical beam control system could be used in many laser radar remote sensing applications including meteorological studies and agricultural or environmental surveys in addition to the entry, descent, and landing application.

Exomars mission description and architecture

NASA Astrophysics Data System (ADS)

Giorgio, Vincenzo; Cassi, Carlo; Santoro, Pasquale

Msftedit 5.41.15.1507; INTRODUCTION ExoMars is the first mission of the ESA Exploration Programme. It will demonstrate flight and in-situ verification of key exploration enabling technologies to support the European ambitions for future human exploration missions. The main technology demonstration objectives are: Entry, Descent and Landing (EDL) of a large payload on the surface of Mars, Surface mobility via a Rover having several kilometres of mobility range, Access to sub-surface via a Drill to acquire samples down to 2 meters, Automatic sample preparation and distribution for analyses of scientific experiments. In parallel, important scientific objectives will be accomplished through a state-of-the art scientific payload. The ExoMars scientific objectives, in order of priority, are: The search for traces of past and present life, To characterise the water/geochemical environment as a function of depth in the shallow subsurface; To study the surface environment and identify hazards to future human missions; To investigate the planet's subsurface and deep interior to better understand the evolution and habitability of Mars. mission scenario The combinations of the above constraints and other considerations have recently led to a re-definition of the baseline mission that can be summarised as follows: Launch date: Dec 2013 Spacecraft Composite: Carrier + Descent Module Launcher: Ariane 5 from Kourou (back-up Proton from Baikonur) Descent Module released from Mars orbit Courier Module expendable (crash on Mars) Landing between 5° South and 34 ° North Descent Module landing configuration with vented airbags Data relay function provided by a NASA spacecraft. This scenario has been named enhanced baseline, as it basically responds to the need of increasing the payload mass (larger DM mass) and improving the landing accuracy to meet a semi-major axis of the landing error ellipse, downrange of the nominal landing site, of 50 km (3σ) which proved to be unfeasible with the hyperbolic arrival. DESCENT MODULE CONFIGURATION The main DM elements are: the Front Shield, the Back Shell, and the Lander. The Front Shield is an Al honeycomb composite with CFRP skins, covered with light ablative material. Its diameter is 3.4 m. It is separated from the back shell after the deployment of the parachute. The conical Back Shell is made up of a structure covered by a back shield made from the same materials as the front one. This structure provides support for the accommodation of the CM/DM separation mechanisms, some DM equipment such as parachute and thrusters, and the interfaces with the Front Shield and Landing Platform. The Lander is formed by the Landing Platform (Support and Egress Structure, SES and Air Bag System, ABS) and the DM avionic subsystems. It also accommodates the Humboldt Payload. A view is provided in (note the use of the old terminology of GEP for the box housing some of the Humboldt instruments). The Rover with its Pasteur Payload is installed and locked onto the Lander.

7 CFR 319.55-5 - Notice of arrival by permittee.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 5 2011-01-01 2011-01-01 false Notice of arrival by permittee. 319.55-5 Section 319.55-5 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Rice Rules and Regulations § 319.55...

7 CFR 319.55-5 - Notice of arrival by permittee.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Notice of arrival by permittee. 319.55-5 Section 319.55-5 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Rice Rules and Regulations § 319.55...

19 CFR 146.40 - Operator responsibilities for direct delivery.

Code of Federal Regulations, 2013 CFR

2013-04-01

...; DEPARTMENT OF THE TREASURY (CONTINUED) FOREIGN TRADE ZONES Admission of Merchandise to a Zone § 146.40 Operator responsibilities for direct delivery. (a) Arrival of conveyance. Upon arrival at a subzone or zone... Zone Operator's Bond and to relieve the carrier of responsibility. (5) Forward the in-bond or cartage...

19 CFR 146.40 - Operator responsibilities for direct delivery.

Code of Federal Regulations, 2014 CFR

2014-04-01

...; DEPARTMENT OF THE TREASURY (CONTINUED) FOREIGN TRADE ZONES Admission of Merchandise to a Zone § 146.40 Operator responsibilities for direct delivery. (a) Arrival of conveyance. Upon arrival at a subzone or zone... Zone Operator's Bond and to relieve the carrier of responsibility. (5) Forward the in-bond or cartage...

19 CFR 146.40 - Operator responsibilities for direct delivery.

Code of Federal Regulations, 2011 CFR

2011-04-01

...; DEPARTMENT OF THE TREASURY (CONTINUED) FOREIGN TRADE ZONES Admission of Merchandise to a Zone § 146.40 Operator responsibilities for direct delivery. (a) Arrival of conveyance. Upon arrival at a subzone or zone... Zone Operator's Bond and to relieve the carrier of responsibility. (5) Forward the in-bond or cartage...

19 CFR 146.40 - Operator responsibilities for direct delivery.

Code of Federal Regulations, 2012 CFR

2012-04-01

...; DEPARTMENT OF THE TREASURY (CONTINUED) FOREIGN TRADE ZONES Admission of Merchandise to a Zone § 146.40 Operator responsibilities for direct delivery. (a) Arrival of conveyance. Upon arrival at a subzone or zone... Zone Operator's Bond and to relieve the carrier of responsibility. (5) Forward the in-bond or cartage...

19 CFR 146.40 - Operator responsibilities for direct delivery.

Code of Federal Regulations, 2010 CFR

2010-04-01

...; DEPARTMENT OF THE TREASURY (CONTINUED) FOREIGN TRADE ZONES Admission of Merchandise to a Zone § 146.40 Operator responsibilities for direct delivery. (a) Arrival of conveyance. Upon arrival at a subzone or zone... Zone Operator's Bond and to relieve the carrier of responsibility. (5) Forward the in-bond or cartage...

7 CFR 319.41-4 - Notice of arrival by permittee.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 5 2011-01-01 2011-01-01 false Notice of arrival by permittee. 319.41-4 Section 319.41-4 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Indian Corn or Maize, Broomcorn, and...

19 CFR 162.5 - Search of arriving vehicles and aircraft.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Search of arriving vehicles and aircraft. 162.5 Section 162.5 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Inspection, Examination, and Search...

7 CFR 319.41-4 - Notice of arrival by permittee.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Notice of arrival by permittee. 319.41-4 Section 319.41-4 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Indian Corn or Maize, Broomcorn, and...

Field evaluation of flight deck procedures for flying CTAS descents

DOT National Transportation Integrated Search

1997-01-01

Flight deck descent procedures were developed for a field evaluation of the CTAS Descent Advisor conducted in the fall of 1995. During this study, CTAS descent clearances were issued to 185 commercial flights at Denver International Airport. Data col...

26 CFR 1.102-1 - Gifts and inheritances.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Gifts and inheritances. 1.102-1 Section 1.102-1...) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.102-1 Gifts and inheritances... inheritances. The income from any property received as a gift, or under a will or statute of descent and...

A Shared Heritage: Afro-Latin@s and Black History

ERIC Educational Resources Information Center

Busey, Christopher L.; Cruz, Bárbara C.

2015-01-01

As the Latin@ population continues to grow in the United States, it is imperative that social studies teachers are aware of the rich history and sociocultural complexities of Latin@ identity. In particular, there is a large population of Latin@s of African descent throughout Latin America, the Caribbean, and North America. However, Afro-Latin@s…

African Immigrant Families in the United States: Surviving the Sociocultural Tide

ERIC Educational Resources Information Center

Obiakor, Festus E.; Afolayan, Michael O.

2007-01-01

There exists a significant yet unique level and magnitude of problems that immigrants of African descent have to grapple with in their efforts to settle down into their new American lives. This fact makes the continuity of the natal culture very difficult. However, in spite of their many problems, African immigrants never lose touch with their…

Statistics on continuous IBD data: Exact distribution evaluation for a pair of full(half)-sibs and a pair of a (great-) grandchild with a (great-) grandparent

PubMed Central

Stefanov, Valeri T

2002-01-01

Background Pairs of related individuals are widely used in linkage analysis. Most of the tests for linkage analysis are based on statistics associated with identity by descent (IBD) data. The current biotechnology provides data on very densely packed loci, and therefore, it may provide almost continuous IBD data for pairs of closely related individuals. Therefore, the distribution theory for statistics on continuous IBD data is of interest. In particular, distributional results which allow the evaluation of p-values for relevant tests are of importance. Results A technology is provided for numerical evaluation, with any given accuracy, of the cumulative probabilities of some statistics on continuous genome data for pairs of closely related individuals. In the case of a pair of full-sibs, the following statistics are considered: (i) the proportion of genome with 2 (at least 1) haplotypes shared identical-by-descent (IBD) on a chromosomal segment, (ii) the number of distinct pieces (subsegments) of a chromosomal segment, on each of which exactly 2 (at least 1) haplotypes are shared IBD. The natural counterparts of these statistics for the other relationships are also considered. Relevant Maple codes are provided for a rapid evaluation of the cumulative probabilities of such statistics. The genomic continuum model, with Haldane's model for the crossover process, is assumed. Conclusions A technology, together with relevant software codes for its automated implementation, are provided for exact evaluation of the distributions of relevant statistics associated with continuous genome data on closely related individuals. PMID:11996673

How to define pathologic pelvic floor descent in MR defecography during defecation?

PubMed

Schawkat, Khoschy; Heinrich, Henriette; Parker, Helen L; Barth, Borna K; Mathew, Rishi P; Weishaupt, Dominik; Fox, Mark; Reiner, Caecilia S

2018-06-01

To assess the extents of pelvic floor descent both during the maximal straining phase and the defecation phase in healthy volunteers and in patients with pelvic floor disorders, studied with MR defecography (MRD), and to define specific threshold values for pelvic floor descent during the defecation phase. Twenty-two patients (mean age 51 ± 19.4) with obstructed defecation and 20 healthy volunteers (mean age 33.4 ± 11.5) underwent 3.0T MRD in supine position using midsagittal T2-weighted images. Two radiologists performed measurements in reference to PCL-lines in straining and during defecation. In order to identify cutoff values of pelvic floor measurements for diagnosis of pathologic pelvic floor descent [anterior, middle, and posterior compartments (AC, MC, PC)], receiver-operating characteristic (ROC) curves were plotted. Pelvic floor descent of all three compartments was significantly larger during defecation than at straining in patients and healthy volunteers (p < 0.002). When grading pelvic floor descent in the straining phase, only two healthy volunteers showed moderate PC descent (10%), which is considered pathologic. However, when applying the grading system during defecation, PC descent was overestimated with 50% of the healthy volunteers (10 of 20) showing moderate PC descent. The AUC for PC measurements during defecation was 0.77 (p = 0.003) and suggests a cutoff value of 45 mm below the PCL to identify patients with pathologic PC descent. With the adapted cutoff, only 15% of healthy volunteers show pathologic PC descent during defecation. MRD measurements during straining and defecation can be used to differentiate patients with pelvic floor dysfunction from healthy volunteers. However, different cutoff values should be used during straining and during defecation to define normal or pathologic PC descent.

Evaluation of pelvic descent disorders by dynamic contrast roentgenography.

PubMed

Takano, M; Hamada, A

2000-10-01

For precise diagnosis and rational treatment of the increasing number of patients with descent of intrapelvic organ(s) and anatomic plane(s), dynamic contrast roentgenography of multiple intrapelvic organs and planes is described. Sixty-six patients, consisting of 11 males, with a mean age (+/- standard deviation) of 65.6+/-14.2 years and with chief complaints of intrapelvic organ and perineal descent or defecation problems, were examined in this study. Dynamic contrast roentgenography was obtained by opacifying the ileum, urinary bladder, vagina, rectum, and the perineum. Films were taken at both squeeze and strain phases. On the films the lowest points of each organ and plane were plotted, and the distances from the standard line drawn at the upper surface of the sacrum were measured. The values were corrected to percentages according to the height of the sacrococcygeal bone of each patient. From these corrected values, organ or plane descents at strain and squeeze were diagnosed and graphically demonstrated as a descentgram in each patient. Among 17 cases with subjective symptoms of bladder descent, 9 cases (52.9 percent) showed roentgenographic descent. By the same token, among the cases with subjective feeling of descent of the vagina, uterus, peritoneum, perineum, rectum, and anus, roentgenographic descent was confirmed in 15 of 20 (75 percent), 7 of 9 (77.8 percent), 6 of 16 (37.5 percent), 33 of 33 (100 percent), 25 of 37 (67.6 percent), and 22 of 36 (61.6 percent), respectively. The descentgrams were divided into three patterns: anorectal descent type, female genital descent type, and total organ descent type. Dynamic contrast roentgenography and successive descentgraphy of multiple intrapelvic organs and planes are useful for objective diagnosis and rational treatment of patients with descent disorders of the intrapelvic organ(s) and plane(s).

7 CFR 319.37-11 - Arrival notification.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Arrival notification. 319.37-11 Section 319.37-11 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Nursery Stock, Plants, Roots, Bulbs, Seeds, and Other Plant Products 1,2 § 319.37-11...

7 CFR 319.37-11 - Arrival notification.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 5 2011-01-01 2011-01-01 false Arrival notification. 319.37-11 Section 319.37-11 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Nursery Stock, Plants, Roots, Bulbs, Seeds, and Other Plant Products 1,2 § 319.37-11...

An Analysis of the Relationship Between the Heat Index and Arrivals in the Emergency Department

PubMed Central

Levy, Matthew; Broccoli, Morgan; Cole, Gai; Jenkins, J Lee; Klein, Eili Y.

2015-01-01

Background: Heatwaves are one of the most deadly weather-related events in the United States and account for more deaths annually than hurricanes, tornadoes, floods, and earthquakes combined. However, there are few statistically rigorous studies of the effect of heatwaves on emergency department (ED) arrivals. A better understanding of this relationship can help hospitals plan better and provide better care for patients during these types of events. Methods: A retrospective review of all ED patient arrivals that occurred from April 15 through August 15 for the years 2008 through 2013 was performed. Daily patient arrival data were combined with weather data (temperature and humidity) to examine the potential relationships between the heat index and ED arrivals as well as the length of time patients spend in the ED using generalized additive models. In particular the effect the 2012 heat wave that swept across the United States, and which was hypothesized to increase arrivals was examined. Results: While there was no relationship found between the heat index and arrivals on a single day, a non-linear relationship was found between the mean three-day heat index and the number of daily arrivals. As the mean three-day heat index initially increased, the number of arrivals significantly declined. However, as the heat index continued to increase, the number of arrivals increased. It was estimated that there was approximately a 2% increase in arrivals when the mean heat index for three days approached 100°F. This relationship was strongest for adults aged 18-64, as well as for patients arriving with lower acuity. Additionally, a positive relationship was noted between the mean three-day heat index and the length of stay (LOS) for patients in the ED, but no relationship was found for the time from which a patient was first seen to when a disposition decision was made. No significant relationship was found for the effect of the 2012 heat wave on ED arrivals, though it did have an effect on patient LOS. Conclusion: A single hot day has only a limited effect on ED arrivals, but continued hot weather has a cumulative effect. When the heat index is high (~90°F) for a number of days in a row, this curtails peoples activities, but if the heat index is very hot (~100°F) this likely results in an exacerbation of underlying conditions as well as heat-related events that drives an increase in ED arrivals. Periods of high heat also affects the length of stay of patients either by complicating care or by making it more difficult to discharge patients. PMID:26579329

Analysis of various descent trajectories for a hypersonic-cruise, cold-wall research airplane

NASA Technical Reports Server (NTRS)

Lawing, P. L.

1975-01-01

The probable descent operating conditions for a hypersonic air-breathing research airplane were examined. Descents selected were cruise angle of attack, high dynamic pressure, high lift coefficient, turns, and descents with drag brakes. The descents were parametrically exercised and compared from the standpoint of cold-wall (367 K) aircraft heat load. The descent parameters compared were total heat load, peak heating rate, time to landing, time to end of heat pulse, and range. Trends in total heat load as a function of cruise Mach number, cruise dynamic pressure, angle-of-attack limitation, pull-up g-load, heading angle, and drag-brake size are presented.

Mars Science Laboratory: Entry, Descent, and Landing System Performance

NASA Technical Reports Server (NTRS)

Way, David W.; Powell, Richard W.; Chen, Allen; SanMartin, A. Miguel; Burkhart, P. Daniel; Mendeck, Gavin F.

2007-01-01

In 2010, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems, by delivering the largest and most capable rover to date to the surface of Mars. To do so, MSL will fly a guided lifting entry at a lift-to-drag ratio in excess of that ever flown at Mars, deploy the largest parachute ever at Mars, and perform a novel Sky Crane maneuver. Through improved altitude capability, increased latitude coverage, and more accurate payload delivery, MSL is allowing the science community to consider the exploration of previously inaccessible regions of the planet. The MSL EDL system is a new EDL architecture based on Viking heritage technologies and designed to meet the challenges of landing increasing massive payloads on Mars. In accordance with level-1 requirements, the MSL EDL system is being designed to land an 850 kg rover to altitudes as high as 1 km above the Mars Orbiter Laser Altimeter defined areoid within 10 km of the desired landing site. Accordingly, MSL will enter the largest entry mass, fly the largest 70 degree sphere-cone aeroshell, generate the largest hypersonic lift-to-drag ratio, and deploy the largest Disk-Gap-Band supersonic parachute of any previous mission to Mars. Major EDL events include a hypersonic guided entry, supersonic parachute deploy and inflation, subsonic heatshield jettison, terminal descent sensor acquisition, powered descent initiation, sky crane terminal descent, rover touchdown detection, and descent stage flyaway. Key performance metrics, derived from level-1 requirements and tracked by the EDL design team to indicate performance capability and timeline margins, include altitude and range at parachute deploy, time on radar, and propellant use. The MSL EDL system, which will continue to develop over the next three years, will enable a notable extension in the advancement of Mars surface science by delivering more science capability than ever before to the surface of Mars. This paper describes the current MSL EDL system performance as predicted by end-to-end EDL simulations, highlights the sensitivity of this baseline performance to several key environmental assumptions, and discusses some of the challenges faced in delivering such an unprecedented rover payload to the surface of Mars.

Mars Science Laboratory: Entry, Descent, and Landing System Performance

NASA Technical Reports Server (NTRS)

Way, David W.; Powell, Richard W.; Chen, Allen; Steltzner, Adam D.; San Martin, Alejandro M.; Burkhart, Paul D.; mendeck, Gavin F.

2006-01-01

In 2010, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems, by delivering the largest and most capable rover to date to the surface of Mars. To do so, MSL will fly a guided lifting entry at a lift-to-drag ratio in excess of that ever flown at Mars, deploy the largest parachute ever at Mars, and perform a novel Sky Crane maneuver. Through improved altitude capability, increased latitude coverage, and more accurate payload delivery, MSL is allowing the science community to consider the exploration of previously inaccessible regions of the planet. The MSL EDL system is a new EDL architecture based on Viking heritage technologies and designed to meet the challenges of landing increasing massive payloads on Mars. In accordance with level-1 requirements, the MSL EDL system is being designed to land an 850 kg rover to altitudes as high as 1 km above the Mars Orbiter Laser Altimeter defined areoid within 10 km of the desired landing site. Accordingly, MSL will enter the largest entry mass, fly the largest 70 degree sphere-cone aeroshell, generate the largest hypersonic lift-to-drag ratio, and deploy the largest Disk-Gap-Band supersonic parachute of any previous mission to Mars. Major EDL events include a hypersonic guided entry, supersonic parachute deploy and inflation, subsonic heatshield jettison, terminal descent sensor acquisition, powered descent initiation, sky crane terminal descent, rover touchdown detection, and descent stage flyaway. Key performance metrics, derived from level-1 requirements and tracked by the EDL design team to indicate performance capability and timeline margins, include altitude and range at parachute deploy, time on radar, and propellant use. The MSL EDL system, which will continue to develop over the next three years, will enable a notable extension in the advancement of Mars surface science by delivering more science capability than ever before to the surface of Mars. This paper describes the current MSL EDL system performance as predicted by end-to-end EDL simulations, highlights the sensitivity of this baseline performance to several key environmental assumptions, and discusses some of the challenges faced in delivering such an unprecedented rover payload to the surface of Mars.

Concept of Operations for Interval Management Arrivals and Approach

NASA Technical Reports Server (NTRS)

Hicok, Daniel S.; Barmore, Bryan E.

2016-01-01

This paper presents the concept of operations for interval management operations to be deployed in the US National Airspace System (NAS) by the Federal Aviation Administration (FAA) after 2020. The use of interval management operations is described that begin in en route airspace and continue to a termination point inside the arrival terminal area, in a terminal environment that includes other arrival management tools such as arrival metering, Ground-based Interval Management - Spacing (GIM-S), and Terminal Sequencing and Spacing (TSAS). The roles of Air Traffic Controllers and Flight Crews and the ground automation tools that are used by Air Traffic Controllers to enable the primary operation and variations are described.

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.

Explaining Success and Failure in Mainstream Schooling through the Lens of Cultural Continuities and Discontinuities: Two Case Studies

ERIC Educational Resources Information Center

Markose, Susan; Hellsten, Meeri

2009-01-01

This article investigates the home literacy practices of two immigrant families, one each of Lebanese and Chinese descent. It explores the consequences of mismatches between home and school literacy practices in relation to mainstream academic outcomes. Two mothers of the families in this study are interviewed about their beliefs and parenting…

The Educational Resettlement of Refugee Children: Examining Several Theoretical Approaches

ERIC Educational Resources Information Center

Lerner, Amy B.

2012-01-01

Each year, approximately 100,000 refugees arrive in the United States (Refugee Council USA). Nearly half of these arrivals are children. The number of refugees worldwide has more than sextupled since the 1950s, and according to the United States Committee for Refugees and immigrants (USCRI) this number is expected to continue to grow in coming…

Opening Spaces of Conversation: Citizen Education for Newcomers as a Democratic Practice

ERIC Educational Resources Information Center

Wildemeersch, Danny

2017-01-01

The arrival of newcomers in our societies "impinges upon us" (Peter Jarvis). Adult and continuing education are invited to take a stance. In response to this, I explore how relevant citizenship education for and with newcomers can be conceived of. In the first place, I explore how the arrival of newcomers triggers ambivalent reactions…

14 CFR 93.28 - One-for-one trade of Arrival Authorizations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false One-for-one trade of Arrival Authorizations. 93.28 Section 93.28 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at Chicago O'Hare International...

Process improvement to enhance existing stroke team activity toward more timely thrombolytic treatment.

PubMed

Cho, Han-Jin; Lee, Kyung Yul; Nam, Hyo Suk; Kim, Young Dae; Song, Tae-Jin; Jung, Yo Han; Choi, Hye-Yeon; Heo, Ji Hoe

2014-10-01

Process improvement (PI) is an approach for enhancing the existing quality improvement process by making changes while keeping the existing process. We have shown that implementation of a stroke code program using a computerized physician order entry system is effective in reducing the in-hospital time delay to thrombolysis in acute stroke patients. We investigated whether implementation of this PI could further reduce the time delays by continuous improvement of the existing process. After determining a key indicator [time interval from emergency department (ED) arrival to intravenous (IV) thrombolysis] and conducting data analysis, the target time from ED arrival to IV thrombolysis in acute stroke patients was set at 40 min. The key indicator was monitored continuously at a weekly stroke conference. The possible reasons for the delay were determined in cases for which IV thrombolysis was not administered within the target time and, where possible, the problems were corrected. The time intervals from ED arrival to the various evaluation steps and treatment before and after implementation of the PI were compared. The median time interval from ED arrival to IV thrombolysis in acute stroke patients was significantly reduced after implementation of the PI (from 63.5 to 45 min, p=0.001). The variation in the time interval was also reduced. A reduction in the evaluation time intervals was achieved after the PI [from 23 to 17 min for computed tomography scanning (p=0.003) and from 35 to 29 min for complete blood counts (p=0.006)]. PI is effective for continuous improvement of the existing process by reducing the time delays between ED arrival and IV thrombolysis in acute stroke patients.

Automatic toilet seat lowering apparatus

DOEpatents

Guerty, Harold G.

1994-09-06

A toilet seat lowering apparatus includes a housing defining an internal cavity for receiving water from the water supply line to the toilet holding tank. A descent delay assembly of the apparatus can include a stationary dam member and a rotating dam member for dividing the internal cavity into an inlet chamber and an outlet chamber and controlling the intake and evacuation of water in a delayed fashion. A descent initiator is activated when the internal cavity is filled with pressurized water and automatically begins the lowering of the toilet seat from its upright position, which lowering is also controlled by the descent delay assembly. In an alternative embodiment, the descent initiator and the descent delay assembly can be combined in a piston linked to the rotating dam member and provided with a water channel for creating a resisting pressure to the advancing piston and thereby slowing the associated descent of the toilet seat. A toilet seat lowering apparatus includes a housing defining an internal cavity for receiving water from the water supply line to the toilet holding tank. A descent delay assembly of the apparatus can include a stationary dam member and a rotating dam member for dividing the internal cavity into an inlet chamber and an outlet chamber and controlling the intake and evacuation of water in a delayed fashion. A descent initiator is activated when the internal cavity is filled with pressurized water and automatically begins the lowering of the toilet seat from its upright position, which lowering is also controlled by the descent delay assembly. In an alternative embodiment, the descent initiator and the descent delay assembly can be combined in a piston linked to the rotating dam member and provided with a water channel for creating a resisting pressure to the advancing piston and thereby slowing the associated descent of the toilet seat.

Mirror gait retraining for the treatment of patellofemoral pain in female runners

PubMed Central

Willy, Richard W.; Scholz, John P.; Davis, Irene S.

2012-01-01

Background Abnormal hip mechanics are often implicated in female runners with patellofemoral pain. We sought to evaluate a simple gait retraining technique, using a full-length mirror, in female runners with patellofemoral pain and abnormal hip mechanics. Transfer of the new motor skill to the untrained tasks of single leg squat and step descent was also evaluated. Methods Ten female runners with patellofemoral pain completed 8 sessions of mirror and verbal feedback on their lower extremity alignment during treadmill running. During the last 4 sessions, mirror and verbal feedback were progressively removed. Hip mechanics were assessed during running gait, a single leg squat and a step descent, both pre- and post-retraining. Subjects returned to their normal running routines and analyses were repeated at 1-month and 3-month post-retraining. Data were analyzed via repeated measures analysis of variance. Findings Subjects reduced peaks of hip adduction, contralateral pelvic drop, and hip abduction moment during running (P<0.05, effect size=0.69–2.91). Skill transfer to single leg squatting and step descent was noted (P<0.05, effect size=0.91–1.35). At 1 and 3 months post retraining, most mechanics were maintained in the absence of continued feedback. Subjects reported improvements in pain and function (P<0.05, effect size=3.81–7.61) and maintained through 3 months post retraining. Interpretation Mirror gait retraining was effective in improving mechanics and measures of pain and function. Skill transfer to the untrained tasks of squatting and step descent indicated that a higher level of motor learning had occurred. Extended follow-up is needed to determine the long term efficacy of this treatment. PMID:22917625

The nature of crustal boundaries: combined interpretation of wide-angle and normal-incidence seismic data

NASA Astrophysics Data System (ADS)

Long, Roger E.; Matthews, Patricia A.; Graham, Daniel P.

1994-04-01

After a few seconds two-way traveltime, normal-incidence seismic reflection sections are composed mainly of assemblages of short reflections. Very rarely are seen continuous reflections that might correspond to the Moho or a mid-crustal discontinuity. The inferred continuity of these boundaries has traditionally come from refraction seismology. There is now a body of high quality, coincident wide-angle and normal-incidence seismic data that have been recorded with 50-100 m shot spacing and with high frequency sources (e.g. MOBIL, BABEL). The complexity and characteristics of the wide-angle arrivals seen on these data suggest that they do not originate from continuous boundaries. It is suggested that these arrivals are reflections from the same assemblage of short length reflectors that are responsible for normal-incidence reflections. Seismic velocities below the middle crust may (1) change corresponding to normal-incidence reflectivity, or (2) generally increase with depth with localised sills or lens structures of different velocity accounting for the observed reflections. Wide-angle arrivals that have traditionally been identified as reflections from crustal boundaries (e.g. the mid-crust and Moho) and which were considered indicative of a sharp velocity discontinuity from continuous boundaries, may instead result from a concentration of lamellae.

Validation of Genome-Wide Prostate Cancer Associations in Men of African Descent

PubMed Central

Chang, Bao-Li; Spangler, Elaine; Gallagher, Stephen; Haiman, Christopher A.; Henderson, Brian; Isaacs, William; Benford, Marnita L.; Kidd, LaCreis R.; Cooney, Kathleen; Strom, Sara; Ann Ingles, Sue; Stern, Mariana C.; Corral, Roman; Joshi, Amit D.; Xu, Jianfeng; Giri, Veda N.; Rybicki, Benjamin; Neslund-Dudas, Christine; Kibel, Adam S.; Thompson, Ian M.; Leach, Robin J.; Ostrander, Elaine A.; Stanford, Janet L.; Witte, John; Casey, Graham; Eeles, Rosalind; Hsing, Ann W.; Chanock, Stephen; Hu, Jennifer J.; John, Esther M.; Park, Jong; Stefflova, Klara; Zeigler-Johnson, Charnita; Rebbeck, Timothy R.

2010-01-01

Background Genome-wide association studies (GWAS) have identified numerous prostate cancer susceptibility alleles, but these loci have been identified primarily in men of European descent. There is limited information about the role of these loci in men of African descent. Methods We identified 7,788 prostate cancer cases and controls with genotype data for 47 GWAS-identified loci. Results We identified significant associations for SNP rs10486567 at JAZF1, rs10993994 at MSMB, rs12418451 and rs7931342 at 11q13, and rs5945572 and rs5945619 at NUDT10/11. These associations were in the same direction and of similar magnitude as those reported in men of European descent. Significance was attained at all report prostate cancer susceptibility regions at chromosome 8q24, including associations reaching genome-wide significance in region 2. Conclusion We have validated in men of African descent the associations at some, but not all, prostate cancer susceptibility loci originally identified in European descent populations. This may be due to heterogeneity in genetic etiology or in the pattern of genetic variation across populations. Impact The genetic etiology of prostate cancer in men of African descent differs from that of men of European descent. PMID:21071540

Studies of the hormonal control of postnatal testicular descent in the rat.

PubMed

Spencer, J R; Vaughan, E D; Imperato-McGinley, J

1993-03-01

Dihydrotestosterone is believed to control the transinguinal phase of testicular descent based on hormonal manipulation studies performed in postnatal rats. In the present study, these hormonal manipulation experiments were repeated, and the results were compared with those obtained using the antiandrogens flutamide and cyproterone acetate. 17 beta-estradiol completely blocked testicular descent, but testosterone and dihydrotestosterone were equally effective in reversing this inhibition. Neither flutamide nor cyproterone acetate prevented testicular descent in postnatal rats despite marked peripheral antiandrogenic action. Further analysis of the data revealed a correlation between testicular size and descent. Androgen receptor blockade did not produce a marked reduction in testicular size and consequently did not prevent testicular descent, whereas estradiol alone caused marked testicular atrophy and testicular maldescent. Reduction of the estradiol dosage or concomitant administration of androgens or human chorionic gonadotropin resulted in both increased testicular size and degree of descent. These data suggest that growth of the neonatal rat testis may contribute to its passage into the scrotum.

On the Borders: The Arrival of Irregular Immigrants in Malta--Some Implications for Education

ERIC Educational Resources Information Center

Mercieca, Duncan

2007-01-01

This paper concerns the issue of the continual arrival of irregular immigrants in Malta and the problems that ensue. The view generally held is that we need to respond to the needs of irregular immigrants by providing services. However, with reference to some of Jacques Derrida's ideas, I argue in this paper that the "other"/immigrant is…

Climate Change and Phenology: Empoasca fabae (Hemiptera: Cicadellidae) Migration and Severity of Impact

PubMed Central

Lamp, William O.

2015-01-01

Climate change can benefit individual species, but when pest species are enhanced by warmer temperatures agricultural productivity may be placed at greater risk. We analyzed the effects of temperature anomaly on arrival date and infestation severity of potato leafhopper, Empoasca fabae Harris, a classic new world long distance migrant, and a significant pest in several agricultural crops. We compiled E. fabae arrival dates and infestation severity data at different states in USA from existing literature reviews and agricultural extension records from 1951–2012, and examined the influence of temperature anomalies at each target state or overwintering range on the date of arrival and severity of infestation. Average E. fabae arrival date at different states reveal a clear trend along the south-north axis, with earliest arrival closest to the overwintering range. E. fabae arrival has advanced by 10 days over the last 62 years. E. fabae arrived earlier in warmer years in relation to each target state level temperature anomaly (3.0 days / °C increase in temperature anomaly). Increased temperature had a significant and positive effect on the severity of infestation, and arrival date had a marginal negative effect on severity. These relationships suggest that continued warming could advance the time of E. fabae colonization and increase their impact on affected crops. PMID:25970705

Intermediate addition multifocals provide safe stair ambulation with adequate 'short-term' reading.

PubMed

Elliott, David B; Hotchkiss, John; Scally, Andrew J; Foster, Richard; Buckley, John G

2016-01-01

A recent randomised controlled trial indicated that providing long-term multifocal wearers with a pair of distance single-vision spectacles for use outside the home reduced falls risk in active older people. However, it also found that participants disliked continually switching between using two pairs of glasses and adherence to the intervention was poor. In this study we determined whether intermediate addition multifocals (which could be worn most of the time inside and outside the home and thus avoid continual switching) could provide similar gait safety on stairs to distance single vision spectacles whilst also providing adequate 'short-term' reading and near vision. Fourteen healthy long-term multifocal wearers completed stair ascent and descent trials over a 3-step staircase wearing intermediate and full addition bifocals and progression-addition lenses (PALs) and single-vision distance spectacles. Gait safety/caution was assessed using foot clearance measurements (toe on ascent, heel on descent) over the step edges and ascent and descent duration. Binocular near visual acuity, critical print size and reading speed were measured using Bailey-Lovie near charts and MNRead charts at 40 cm. Gait safety/caution measures were worse with full addition bifocals and PALs compared to intermediate bifocals and PALs. The intermediate PALs provided similar gait ascent/descent measures to those with distance single-vision spectacles. The intermediate addition PALs also provided good reading ability: Near word acuity and MNRead critical print size were better with the intermediate addition PALs than with the single-vision lenses (p < 0.0001), with a mean near visual acuity of 0.24 ± 0.13 logMAR (~N5.5) which is satisfactory for most near vision tasks when performed for a short period of time. The better ability to 'spot read' with the intermediate addition PALs compared to single-vision spectacles suggests that elderly individuals might better comply with the use of intermediate addition PALs outside the home. A lack of difference in gait parameters for the intermediate addition PALs compared to distance single-vision spectacles suggests they could be usefully used to help prevent falls in older well-adapted full addition PAL wearers. A randomised controlled trial to investigate the usefulness of intermediate multifocals in preventing falls seems warranted. © 2015 The Authors Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.

Correlation Between Echodefecography and 3-Dimensional Vaginal Ultrasonography in the Detection of Perineal Descent in Women With Constipation Symptoms.

PubMed

Murad-Regadas, Sthela M; Pinheiro Regadas, Francisco Sergio; Rodrigues, Lusmar V; da Silva Vilarinho, Adjra; Buchen, Guilherme; Borges, Livia Olinda; Veras, Lara B; da Cruz, Mariana Murad

2016-12-01

Defecography is an established method of evaluating dynamic anorectal dysfunction, but conventional defecography does not allow for visualization of anatomic structures. The purpose of this study was to describe the use of dynamic 3-dimensional endovaginal ultrasonography for evaluating perineal descent in comparison with echodefecography (3-dimensional anorectal ultrasonography) and to study the relationship between perineal descent and symptoms and anatomic/functional abnormalities of the pelvic floor. This was a prospective study. The study was conducted at a large university tertiary care hospital. Consecutive female patients were eligible if they had pelvic floor dysfunction, obstructed defecation symptoms, and a score >6 on the Cleveland Clinic Florida Constipation Scale. Each patient underwent both echodefecography and dynamic 3-dimensional endovaginal ultrasonography to evaluate posterior pelvic floor dysfunction. Normal perineal descent was defined on echodefecography as puborectalis muscle displacement ≤2.5 cm; excessive perineal descent was defined as displacement >2.5 cm. Of 61 women, 29 (48%) had normal perineal descent; 32 (52%) had excessive perineal descent. Endovaginal ultrasonography identified 27 of the 29 patients in the normal group as having anorectal junction displacement ≤1 cm (mean = 0.6 cm; range, 0.1-1.0 cm) and a mean anorectal junction position of 0.6 cm (range, 0-2.3 cm) above the symphysis pubis during the Valsalva maneuver and correctly identified 30 of the 32 patients in the excessive perineal descent group. The κ statistic showed almost perfect agreement (κ = 0.86) between the 2 methods for categorization into the normal and excessive perineal descent groups. Perineal descent was not related to fecal or urinary incontinence or anatomic and functional factors (sphincter defects, pubovisceral muscle defects, levator hiatus area, grade II or III rectocele, intussusception, or anismus). The study did not include a control group without symptoms. Three-dimensional endovaginal ultrasonography is a reliable technique for assessment of perineal descent. Using this technique, excessive perineal descent can be defined as displacement of the anorectal junction >1 cm and/or its position below the symphysis pubis on Valsalva maneuver.

Scientific and Technical Support for the Galileo Net Flux Radiometer Experiment

NASA Technical Reports Server (NTRS)

Sromovsky, Lawrence A.

1997-01-01

This report describes work in support of the Galileo Net Flux Radiometer (NFR), an instrument mounted on the Galileo probe, a spacecraft designed for entry into and direct measurements of Jupiter's atmosphere. Tasks originally proposed for the post launch period covered by NCC 2-854 are briefly as follows: attend and support PSG (Project Science Group) and other project science meetings; support in-flight checkouts; maintain and keep safe the spare instrument and GSE (Ground Support Equipment); organize and maintain documentation; finish NFR calibration measurements, documentation, and analysis; characterize and diagnose instrument anomalies; develop descent data analysis tools; and science data analysis and publication. Because we had the capability to satisfy a project support need we also subsequently proposed and were funded to make ground-based observations of Jupiter during the period surrounding the Galileo arrival at Jupiter, using the Swedish Solar Telescope at La Palma, Canary Islands. The following section provides background information on the NFR instrument. Section 3 contains the final report of work done.

Aerial Deployment and Inflation System for Mars Helium Balloons

NASA Technical Reports Server (NTRS)

Lachenmeler, Tim; Fairbrother, Debora; Shreves, Chris; Hall, Jeffery, L.; Kerzhanovich, Viktor V.; Pauken, Michael T.; Walsh, Gerald J.; White, Christopher V.

2009-01-01

A method is examined for safely deploying and inflating helium balloons for missions at Mars. The key for making it possible to deploy balloons that are light enough to be buoyant in the thin, Martian atmosphere is to mitigate the transient forces on the balloon that might tear it. A fully inflated Mars balloon has a diameter of 10 m, so it must be folded up for the trip to Mars, unfolded upon arrival, and then inflated with helium gas in the atmosphere. Safe entry into the Martian atmosphere requires the use of an aeroshell vehicle, which protects against severe heating and pressure loads associated with the hypersonic entry flight. Drag decelerates the aeroshell to supersonic speeds, then two parachutes deploy to slow the vehicle down to the needed safe speed of 25 to 35 m/s for balloon deployment. The parachute system descent dynamic pressure must be approximately 5 Pa or lower at an altitude of 4 km or more above the surface.

A Long Distance Laser Altimeter for Terrain Relative Navigation and Spacecraft Landing

NASA Technical Reports Server (NTRS)

Pierrottet, Diego F.; Amzajerdian, Farzin; Barnes, Bruce W.

2014-01-01

A high precision laser altimeter was developed under the Autonomous Landing and Hazard Avoidance (ALHAT) project at NASA Langley Research Center. The laser altimeter provides slant-path range measurements from operational ranges exceeding 30 km that will be used to support surface-relative state estimation and navigation during planetary descent and precision landing. The altimeter uses an advanced time-of-arrival receiver, which produces multiple signal-return range measurements from tens of kilometers with 5 cm precision. The transmitter is eye-safe, simplifying operations and testing on earth. The prototype is fully autonomous, and able to withstand the thermal and mechanical stresses experienced during test flights conducted aboard helicopters, fixed-wing aircraft, and Morpheus, a terrestrial rocket-powered vehicle developed by NASA Johnson Space Center. This paper provides an overview of the sensor and presents results obtained during recent field experiments including a helicopter flight test conducted in December 2012 and Morpheus flight tests conducted during March of 2014.

KSC-07pd1370

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- STS-117 Pilot Lee Archambault climbs into the shuttle training aircraft, or STA, at KSC's Shuttle Landing Facility. He will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1367

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- STS-117 Pilot Lee Archambault heads for the shuttle training aircraft, or STA, at KSC's Shuttle Landing Facility. He will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1369

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- STS-117 Pilot Lee Archambault heads for the shuttle training aircraft, or STA, at KSC's Shuttle Landing Facility. He will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1371

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- STS-117 Commander Frederick Sturckow settles into his seat in the shuttle training aircraft, or STA, at KSC's Shuttle Landing Facility. He will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1366

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- STS-117 Commander Frederick Sturckow (left) and Pilot Lee Archambault head for the shuttle training aircraft, or STA, at KSC's Shuttle Landing Facility. They will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1376

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- Back at KSC's Shuttle Landing Facility, STS-117 Commander Frederick Sturckow (left) and Pilot Lee Archambault are satisfied with their landing practice in the shuttle training aircraft (STA) behind them. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1377

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- Back at KSC's Shuttle Landing Facility, STS-117 Pilot Lee Archambault and Commander Frederick Sturckow are satisfied with their landing practice in the shuttle training aircraft (STA) behind them. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1372

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- STS-117 Pilot Lee Archambault settles into his seat in the shuttle training aircraft, or STA, at KSC's Shuttle Landing Facility. He will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1368

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- STS-117 Commander Frederick Sturckow climbs into the shuttle training aircraft, or STA, at KSC's Shuttle Landing Facility. He will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

14 CFR 23.69 - Enroute climb/descent.

Code of Federal Regulations, 2010 CFR

2010-01-01

... climb/descent. (a) All engines operating. The steady gradient and rate of climb must be determined at.... The steady gradient and rate of climb/descent must be determined at each weight, altitude, and ambient...

Algorithms for accelerated convergence of adaptive PCA.

PubMed

Chatterjee, C; Kang, Z; Roychowdhury, V P

2000-01-01

We derive and discuss new adaptive algorithms for principal component analysis (PCA) that are shown to converge faster than the traditional PCA algorithms due to Oja, Sanger, and Xu. It is well known that traditional PCA algorithms that are derived by using gradient descent on an objective function are slow to converge. Furthermore, the convergence of these algorithms depends on appropriate choices of the gain sequences. Since online applications demand faster convergence and an automatic selection of gains, we present new adaptive algorithms to solve these problems. We first present an unconstrained objective function, which can be minimized to obtain the principal components. We derive adaptive algorithms from this objective function by using: 1) gradient descent; 2) steepest descent; 3) conjugate direction; and 4) Newton-Raphson methods. Although gradient descent produces Xu's LMSER algorithm, the steepest descent, conjugate direction, and Newton-Raphson methods produce new adaptive algorithms for PCA. We also provide a discussion on the landscape of the objective function, and present a global convergence proof of the adaptive gradient descent PCA algorithm using stochastic approximation theory. Extensive experiments with stationary and nonstationary multidimensional Gaussian sequences show faster convergence of the new algorithms over the traditional gradient descent methods.We also compare the steepest descent adaptive algorithm with state-of-the-art methods on stationary and nonstationary sequences.

Aircraft Configuration and Flight Crew Compliance with Procedures While Conducting Flight Deck Based Interval Management (FIM) Operations

NASA Technical Reports Server (NTRS)

Shay, Rick; Swieringa, Kurt A.; Baxley, Brian T.

2012-01-01

Flight deck based Interval Management (FIM) applications using ADS-B are being developed to improve both the safety and capacity of the National Airspace System (NAS). FIM is expected to improve the safety and efficiency of the NAS by giving pilots the technology and procedures to precisely achieve an interval behind the preceding aircraft by a specific point. Concurrently but independently, Optimized Profile Descents (OPD) are being developed to help reduce fuel consumption and noise, however, the range of speeds available when flying an OPD results in a decrease in the delivery precision of aircraft to the runway. This requires the addition of a spacing buffer between aircraft, reducing system throughput. FIM addresses this problem by providing pilots with speed guidance to achieve a precise interval behind another aircraft, even while flying optimized descents. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR) human-in-the-loop experiment employed 24 commercial pilots to explore the use of FIM equipment to conduct spacing operations behind two aircraft arriving to parallel runways, while flying an OPD during high-density operations. This paper describes the impact of variations in pilot operations; in particular configuring the aircraft, their compliance with FIM operating procedures, and their response to changes of the FIM speed. An example of the displayed FIM speeds used incorrectly by a pilot is also discussed. Finally, this paper examines the relationship between achieving airline operational goals for individual aircraft and the need for ATC to deliver aircraft to the runway with greater precision. The results show that aircraft can fly an OPD and conduct FIM operations to dependent parallel runways, enabling operational goals to be achieved efficiently while maintaining system throughput.

All Recent Mars Landers Have Landed Downrange - Are Mars Atmosphere Models Mis-Predicting Density?

NASA Technical Reports Server (NTRS)

Desai, Prasun N.

2008-01-01

All recent Mars landers (Mars Pathfinder, the two Mars Exploration Rovers Spirit and Opportunity, and the Mars Phoenix Lander) have landed further downrange than their pre-entry predictions. Mars Pathfinder landed 27 km downrange of its prediction [1], Spirit and Opportunity landed 13.4 km and 14.9 km, respectively, downrange from their predictions [2], and Phoenix landed 21 km downrange from its prediction [3]. Reconstruction of their entries revealed a lower density profile than the best a priori atmospheric model predictions. Do these results suggest that there is a systemic issue in present Mars atmosphere models that predict a higher density than observed on landing day? Spirit Landing: The landing location for Spirit was 13.4 km downrange of the prediction as shown in Fig. 1. The navigation errors upon Mars arrival were very small [2]. As such, the entry interface conditions were not responsible for this downrange landing. Consequently, experiencing a lower density during the entry was the underlying cause. The reconstructed density profile that Spirit experienced is shown in Fig. 2, which is plotted as a fraction of the pre-entry baseline prediction that was used for all the entry, descent, and landing (EDL) design analyses. The reconstructed density is observed to be less dense throughout the descent reaching a maximum reduction of 15% at 21 km. This lower density corresponded to approximately a 1- low profile relative to the dispersions predicted. Nearly all the deceleration during the entry occurs within 10- 50 km. As such, prediction of density within this altitude band is most critical for entry flight dynamics analyses and design (e.g., aerodynamic and aerothermodynamic predictions, landing location, etc.).

The Future of Air Traffic Management

NASA Technical Reports Server (NTRS)

Denery, Dallas G.; Erzberger, Heinz; Edwards, Thomas A. (Technical Monitor)

1998-01-01

A system for the control of terminal area traffic to improve productivity, referred to as the Center-TRACON Automation System (CTAS), is being developed at NASA's Ames Research Center under a joint program with the FAA. CTAS consists of a set of integrated tools that provide computer-generated advisories for en-route and terminal area controllers. The premise behind the design of CTAS has been that successful planning of traffic requires accurate trajectory prediction. Data bases consisting of representative aircraft performance models, airline preferred operational procedures and a three dimensional wind model support the trajectory prediction. The research effort has been the design of a set of automation tools that make use of this trajectory prediction capability to assist controllers in overall management of traffic. The first tool, the Traffic Management Advisor (TMA), provides the overall flow management between the en route and terminal areas. A second tool, the Final Approach Spacing Tool (FAST) provides terminal area controllers with sequence and runway advisories to allow optimal use of the runways. The TMA and FAST are now being used in daily operations at Dallas/Ft. Worth airport. Additional activities include the development of several other tools. These include: 1) the En Route Descent Advisor that assist the en route controller in issuing conflict free descents and ascents; 2) the extension of FAST to include speed and heading advisories and the Expedite Departure Path (EDP) that assists the terminal controller in management of departures; and 3) the Collaborative Arrival Planner (CAP) that will assist the airlines in operational decision making. The purpose of this presentation is to review the CTAS concept and to present the results of recent field tests. The paper will first discuss the overall concept and then discuss the status of the individual tools.

Shallow subsurface imaging of northern Cascadia margin using downward continued short-streamer data

NASA Astrophysics Data System (ADS)

Yelisetti, S.; Ghosal, D.; Spence, G.

2017-12-01

Since Eocene, the Juan de Fuca plate has been subducting beneath the North American plate, scrapping off sediments from the down going plate, accreting to the margin forming frontal accretionary wedge, Crescent terrane and the Pacific Rim terrane, which are separated by landward dipping Crescent thrust and Tofino faults. In 1989, the Geological Survey of Canada has acquired several multichannel seismic lines along the northern Cascadia margin to study the subduction zone processes and the formation and distribution of methane hydrates in the accreted sediment section. Seismic reflections and refractions are recorded on a 3.6 km streamer up to 14 s using 4 ms sample rate with 183 m near-offset. In this study, we present the migrated image of line 89-06 which indicate the top of the down-going plate and several landward dipping frontal thrusts. Additionally, a bottom simulating reflector (BSR) is identified over a 20 km distance at a depth of 250 m beneath the seafloor within the accretionary wedge sediments where the water depth is around 1500-2000 m. Preliminary velocity analyses corresponding to the BSR reflection using semblance method indicate high-velocity sediment with P-wave velocities of 2.0 km/s. To better constrain the velocity distribution of such shallow subsurface features, we have analyzed the refracted arrivals from the seaward part of the Tofino basin sediment section. Specifically, we have downward continued the shot and receiver gathers to the seafloor bringing the far offset refracted phases to near offset as first arrivals. Since the refractions are not well captured over the trench deposits due to large water depth ( 2500 m) and limited streamer length, the downward continued results do not show refracted arrivals very clearly at the near offset. In contrast, moving landward along the frontal slope with gradual decrease in water depth to 1300 m and less, the effect of downward continuation seems to be more prominent bringing the refracted phases to near offset more clearly as first arrivals. More detailed first arrival tomographic velocity analysis is currently underway using these downward continued datasets. The tomographic velocity model will then be used as a starting model for future full waveform inversion to obtain the high-resolution velocity and attenuation models of the accreted sediments.

Effects of flutamide and finasteride on rat testicular descent.

PubMed

Spencer, J R; Torrado, T; Sanchez, R S; Vaughan, E D; Imperato-McGinley, J

1991-08-01

The endocrine control of descent of the testis in mammalian species is poorly understood. The androgen dependency of testicular descent was studied in the rat using an antiandrogen (flutamide) and an inhibitor of the enzyme 5 alpha-reductase (finasteride). Androgen receptor blockade inhibited testicular descent more effectively than inhibition of 5 alpha-reductase activity. Moreover, its inhibitory effect was limited to the outgrowth phase of the gubernaculum testis, particularly the earliest stages of outgrowth. Gubernacular size was also significantly reduced in fetuses exposed to flutamide during the outgrowth period. In contrast, androgen receptor blockade or 5 alpha-reductase inhibition applied after the initiation of gubernacular outgrowth or during the regression phase did not affect testicular descent. Successful inhibition of the development of epididymis and vas by prenatal flutamide did not correlate with ipsilateral testicular maldescent, suggesting that an intact epididymis is not required for descent of the testis. Plasma androgen assays confirmed significant inhibition of dihydrotestosterone formation in finasteride-treated rats. These data suggest that androgens, primarily testosterone, are required during the early phases of gubernacular outgrowth for subsequent successful completion of testicular descent.

Testicular descent related to growth hormone treatment.

PubMed

Papadimitriou, Anastasios; Fountzoula, Ioanna; Grigoriadou, Despina; Christianakis, Stratos; Tzortzatou, Georgia

2003-01-01

An 8.7 year-old boy with cryptorchidism and growth hormone (GH) deficiency due to septooptic dysplasia presented testicular descent related to the commencement of hGH treatment. This case suggests a role for GH in testicular descent.

Aircraft Vortex Wake Descent and Decay under Real Atmospheric Effects

DOT National Transportation Integrated Search

1973-10-01

Aircraft vortex wake descent and decay in a real atmosphere is studied analytically. Factors relating to encounter hazard, wake generation, wake descent and stability, and atmospheric dynamics are considered. Operational equations for encounter hazar...

Computational and theoretical investigation of Mars's atmospheric impact on the descent module "Exomars-2018" under aerodynamic deceleration

NASA Astrophysics Data System (ADS)

Golomazov, M. M.; Ivankov, A. A.

2016-12-01

Methods for calculating the aerodynamic impact of the Martian atmosphere on the descent module "Exomars-2018" intended for solving the problem of heat protection of the descent module during aerodynamic deceleration are presented. The results of the investigation are also given. The flow field and radiative and convective heat exchange are calculated along the trajectory of the descent module until parachute system activation.

Apollo lunar descent guidance

NASA Technical Reports Server (NTRS)

Klumpp, A. R.

1974-01-01

Apollo lunar-descent guidance transfers the Lunar Module from a near-circular orbit to touchdown, traversing a 17 deg central angle and a 15 km altitude in 11 min. A group of interactive programs in an onboard computer guide the descent, controlling altitude and the descent propulsion system throttle. A ground-based program pre-computes guidance targets. The concepts involved in this guidance are described. Explicit and implicit guidance are discussed, guidance equations are derived, and the earlier Apollo explicit equation is shown to be an inferior special case of the later implicit equation. Interactive guidance, by which the two-man crew selects a landing site in favorable terrain and directs the trajectory there, is discussed. Interactive terminal-descent guidance enables the crew to control the essentially vertical descent rate in order to land in minimum time with safe contact speed. The altitude maneuver routine uses concepts that make gimbal lock inherently impossible.

Vertical Descent and Landing Tests of a 0.13-Scale Model of the Convair XFY-1 Vertically Rising Airplane in Still Air, TED No. NACA DE 368

NASA Technical Reports Server (NTRS)

Smith, Charlee C., Jr.; Lovell, Powell M., Jr.

1954-01-01

An investigation is being conducted to determine the dynamic stability and control characteristics of a 0.13-scale flying model of Convair XFY-1 vertically rising airplane. This paper presents the results of flight and force tests to determine the stability and control characteristics of the model in vertical descent and landings in still air. The tests indicated that landings, including vertical descent from altitudes representing up to 400 feet for the full-scale airplane and at rates of descent up to 15 or 20 feet per second (full scale), can be performed satisfactorily. Sustained vertical descent in still air probably will be more difficult to perform because of large random trim changes that become greater as the descent velocity is increased. A slight steady head wind or cross wind might be sufficient to eliminate the random trim changes.

Analysis of the Capacity Potential of Current Day and Novel Configurations for New York's John F. Kennedy Airport

NASA Technical Reports Server (NTRS)

Glaab, Patricia; Tamburro, Ralph; Lee, Paul

2016-01-01

In 2015, a series of systems analysis studies were conducted on John F. Kennedy Airport in New York (NY) in a collaborative effort between NASA and the Port Authority of New York and New Jersey (PANYNJ). This work was performed to build a deeper understanding of NY airspace and operations to determine the improvements possible through operational changes with tools currently available, and where new technology is required for additional improvement. The analysis was conducted using tool-based mathematical analyses, video inspection and evaluation using recorded arrival/departure/surface traffic captured by the Aerobahn tool (used by Kennedy Airport for surface metering), and aural data archives available publically through the web to inform the video segments. A discussion of impacts of trajectory and operational choices on capacity is presented, including runway configuration and usage (parallel, converging, crossing, shared, independent, staggered), arrival and departure route characteristics (fix sharing, merges, splits), and how compression of traffic is staged. The authorization in March of 2015 for New York to use reduced spacing under the Federal Aviation Administration (FAA) Wake Turbulence Recategorization (RECAT) also offers significant capacity benefit for New York airports when fully transitioned to the new spacing requirements, and the impact of these changes for New York is discussed. Arrival and departure capacity results are presented for each of the current day Kennedy Airport configurations. While the tools allow many variations of user-selected conditions, the analysis for these studies used arrival-priority, no-winds, additional safety buffer of 5% to the required minimum spacing, and a mix of traffic typical for Kennedy. Two additional "novel" configurations were evaluated. These configurations are of interest to Port Authority and to their airline customers, and are believed to offer near-term capacity benefit with minimal operational and equipage changes. One of these is the addition of an Optimized Profile Descent (OPD) route to runways 22L and 22R, and the other is the simultaneous use of 4 runways, which is not currently done at Kennedy. The background and configuration for each of these is described, and the capacity results are presented along with a discussion of drawbacks and enablers for each.

STS-69 Mission Commander David M. Walker arrives at SLF

NASA Technical Reports Server (NTRS)

1995-01-01

STS-69 Mission Commander David M. Walker arrives at KSC's Shuttle Landing Facility. Walker and four fellow crew members flew in from Johnson Space Center, Houston in the T-38 jet aircraft traditionally used by the astronaut corps. Later today, the countdown will begin as final preparations continue toward liftoff of the Space Shuttle Endeavour at 11:04 a.m. EDT, August 31 on STS-69.

Navy and Marine Corps Medical News. February 17, 2010

DTIC Science & Technology

2010-02-17

arrival at a medical unit or hospital. It continues through their entire road to recovery ," said Robinson. "When our people who are in the fight...Haiti — Marines and Sailors with Combat Logistics Battalion 24 arrived at an empty soccer field Jan. 31 with a mission – transform this recreation...operational stress continuum,” said Hammer. “Sleep, hydration, rotating shifts, and nutrition , are also important in mitigating

A Descent Rate Control Approach to Developing an Autonomous Descent Vehicle

NASA Astrophysics Data System (ADS)

Fields, Travis D.

Circular parachutes have been used for aerial payload/personnel deliveries for over 100 years. In the past two decades, significant work has been done to improve the landing accuracies of cargo deliveries for humanitarian and military applications. This dissertation discusses the approach developed in which a circular parachute is used in conjunction with an electro-mechanical reefing system to manipulate the landing location. Rather than attempt to steer the autonomous descent vehicle directly, control of the landing location is accomplished by modifying the amount of time spent in a particular wind layer. Descent rate control is performed by reversibly reefing the parachute canopy. The first stage of the research investigated the use of a single actuation during descent (with periodic updates), in conjunction with a curvilinear target. Simulation results using real-world wind data are presented, illustrating the utility of the methodology developed. Additionally, hardware development and flight-testing of the single actuation autonomous descent vehicle are presented. The next phase of the research focuses on expanding the single actuation descent rate control methodology to incorporate a multi-actuation path-planning system. By modifying the parachute size throughout the descent, the controllability of the system greatly increases. The trajectory planning methodology developed provides a robust approach to accurately manipulate the landing location of the vehicle. The primary benefits of this system are the inherent robustness to release location errors and the ability to overcome vehicle uncertainties (mass, parachute size, etc.). A separate application of the path-planning methodology is also presented. An in-flight path-prediction system was developed for use in high-altitude ballooning by utilizing the path-planning methodology developed for descent vehicles. The developed onboard system improves landing location predictions in-flight using collected flight information during the ascent and descent. Simulation and real-world flight tests (using the developed low-cost hardware) demonstrate the significance of the improvements achievable when flying the developed system.

THE AFRICAN DESCENT AND GLAUCOMA EVALUATION STUDY (ADAGES): PREDICTORS OF VISUAL FIELD DAMAGE IN GLAUCOMA SUSPECTS

PubMed Central

Khachatryan, Naira; Medeiros, Felipe A.; Sharpsten, Lucie; Bowd, Christopher; Sample, Pamela A.; Liebmann, Jeffrey M.; Girkin, Christopher A.; Weinreb, Robert N.; Miki, Atsuya; Hammel, Na’ama; Zangwill, Linda M.

2015-01-01

Purpose To evaluate racial differences in the development of visual field (VF) damage in glaucoma suspects. Design Prospective, observational cohort study. Methods Six hundred thirty six eyes from 357 glaucoma suspects with normal VF at baseline were included from the multicenter African Descent and Glaucoma Evaluation Study (ADAGES). Racial differences in the development of VF damage were examined using multivariable Cox Proportional Hazard models. Results Thirty one (25.4%) of 122 African descent participants and 47 (20.0%) of 235 European descent participants developed VF damage (p=0.078). In multivariable analysis, worse baseline VF mean deviation, higher mean arterial pressure during follow up, and a race *mean intraocular pressure (IOP) interaction term were significantly associated with the development of VF damage suggesting that racial differences in the risk of VF damage varied by IOP. At higher mean IOP levels, race was predictive of the development of VF damage even after adjusting for potentially confounding factors. At mean IOPs during follow-up of 22, 24 and 26 mmHg, multivariable hazard ratios (95%CI) for the development of VF damage in African descent compared to European descent subjects were 2.03 (1.15–3.57), 2.71 (1.39–5.29), and 3.61 (1.61–8.08), respectively. However, at lower mean IOP levels (below 22 mmHg) during follow-up, African descent was not predictive of the development of VF damage. Conclusion In this cohort of glaucoma suspects with similar access to treatment, multivariate analysis revealed that at higher mean IOP during follow-up, individuals of African descent were more likely to develop VF damage than individuals of European descent. PMID:25597839

[Ethnic differences in forensic psychiatry: an exploratory study at a Dutch forensic psychiatric centre].

PubMed

van der Stoep, T

Compared to the percentage of ethnic minorities in the general population, ethnic minorities are overrepresented in forensic psychiatry. If these minorities are to be treated successfully, we need to know more about this group. So far, however, little is known about the differences between mental disorders and types of offences associated with patients of non-Dutch descent and those associated with patients of Dutch descent.
AIM: To take the first steps to obtain the information we need in order to provide customised care for patients of non-Dutch descent.
METHOD: It proved possible to identify differences between patients of Dutch and non-Dutch descent with regard to treatment, diagnosis and offences committed within a group of patients who were admitted to the forensic psychiatric centre Oostvaarderskliniek during the period 2001 - 2014.
RESULTS: The treatment of patients of non-Dutch descent lasted longer than the treatment of patients of Dutch descent (8.5 year versus 6.6 year). Furthermore, patients from ethnic minority groups were diagnosed more often with schizophrenia (49.1% versus 21.4%), but less often with pervasive developmental disorders or sexual disorders. Patients of non-Dutch descent were more often convicted for sexual crimes where the victim was aged 16 years or older, whereas patients of Dutch descent were convicted of sexual crimes where the victim was under 16.
CONCLUSION: There are differences between patients of Dutch and non-Dutch descent with regard to treatment duration, diagnosis and offences they commit. Future research needs to investigate whether these results are representative for the entire field of forensic psychiatry and to discover the reasons for these differences.

The impact of Asian descent on the incidence of acquired severe aplastic anaemia in children.

PubMed

McCahon, Emma; Tang, Keith; Rogers, Paul C J; McBride, Mary L; Schultz, Kirk R

2003-04-01

Previous studies have suggested an increased incidence of acquired severe aplastic anaemia in Asian populations. We evaluated the incidence of aplastic anaemia in people of Asian descent, using a well-defined paediatric (0-14 years) population in British Columbia, Canada to minimize environmental factors. The incidence in children of East/South-east Asian descent (6.9/million/year) and South Asian (East Indian) descent (7.3/million/year) was higher than for those of White/mixed ethnic descent (1.7/million/year). There appeared to be no contribution by environmental factors. This study shows that Asian children have an increased incidence of severe aplastic anaemia possibly as a result of a genetic predisposition.

Enhancement to Non-Contacting Stress Measurement of Blade Vibration Frequency

NASA Technical Reports Server (NTRS)

Platt, Michael; Jagodnik, John

2011-01-01

A system for turbo machinery blade vibration has been developed that combines time-of-arrival sensors for blade vibration amplitude measurement and radar sensors for vibration frequency and mode identification. The enabling technology for this continuous blade monitoring system is the radar sensor, which provides a continuous time series of blade displacement over a portion of a revolution. This allows the data reduction algorithms to directly calculate the blade vibration frequency and to correctly identify the active modes of vibration. The work in this project represents a significant enhancement in the mode identification and stress calculation accuracy in non-contacting stress measurement system (NSMS) technology when compared to time-of-arrival measurements alone.

Intrascrotal CGRP 8-37 causes a delay in testicular descent in mice.

PubMed

Samarakkody, U K; Hutson, J M

1992-07-01

The genitofemoral nerve is a key factor in the inguinoscrotal descent of the testis. The effect of androgens may be mediated via the central nervous system, which in turn secretes the neurotransmitter calcitonin gene-related peptide (CGRP) at the genitofemoral nerve endings, to cause testicular descent. The effect of endogenous CGRP was examined by weekly injections of a vehicle with or without synthetic antagonist (CGRP 8-37) into the developing scrotum of neonatal mice. The descent of the testis was delayed in the experimental group compared with the control group. At 2 weeks of age 43% of controls had descended testes compared with 0% of experimental animals. At 3 weeks of age 17% of experimentals still had undescended testes, whereas all testes were descended in controls. At 4 weeks 3 testes remained undescended in the experimental group. It is concluded that the CGRP antagonist can retard testicular descent. This result is consistent with the hypothesis that CGRP is an important intermediary in testicular descent.

Linking phenological events in migratory passerines with a changing climate: 50 years in the Laurel Highlands of Pennsylvania.

PubMed

McDermott, Molly E; DeGroote, Lucas W

2017-01-01

Advanced timing of both seasonal migration and reproduction in birds has been strongly associated with a warming climate for many bird species. Phenological responses to climate linking these stages may ultimately impact fitness. We analyzed five decades of banding data from 17 migratory bird species to investigate 1) how spring arrival related to timing of breeding, 2) if the interval between arrival and breeding has changed with increasing spring temperatures, and 3) whether arrival timing or breeding timing best predicted local productivity. Four of 17 species, all mid- to long-distance migrants, hatched young earlier in years when migrants arrived earlier to the breeding grounds (~1:1 day advancement). The interval between arrival on breeding grounds and appearance of juveniles shortened with warmer spring temperatures for 12 species (1-6 days for every 1°C increase) and over time for seven species (1-8 days per decade), suggesting that some migratory passerines adapt to climate change by laying more quickly after arrival or reducing the time from laying to fledging. We found more support for the former, that the rate of reproductive advancement was higher than that for arrival in warm years. Timing of spring arrival and breeding were both poor predictors of avian productivity for most migrants analyzed. Nevertheless, we found evidence that fitness benefits may occur from shifts to earlier spring arrival for the multi-brooded Song Sparrow. Our results uniquely demonstrate that co-occurring avian species are phenologically plastic in their response to climate change on their breeding grounds. If migrants continue to show a weaker response to temperatures during migration than breeding, and the window between arrival and optimal breeding shortens further, biological constraints to plasticity may limit the ability of species to adapt successfully to future warming.

Human chorionic gonadotropin but not the calcitonin gene-related peptide induces postnatal testicular descent in mice.

PubMed

Houle, A M; Gagné, D

1995-01-01

The androgen-regulated paracrine factor, calcitonin gene-related peptide (CGRP), has been proposed as a possible mediator of testicular descent. This peptide has been found to increase rhythmic contractions of gubernaculae and is known to be released by the genitofemoral nerve. We have investigated the ability of CGRP to induce premature testicular descent. CGRP was administered alone, or in combination with human chorionic gonadotropin (hCG) to C57BL/6 male mice postnatally. The extent of testicular descent at 18 days postpartum was then ascertained. The potential relationship between testicular weight and descent was also examined. Our results show that testes of mice treated with either hCG alone, or in combination with 500 ng CGRP, were at a significantly lower position than those of controls by 16% and 17%, respectively. In contrast, mice treated with 500 ng of CGRP alone had testes at a higher position when compared to those of controls, by 19%. In mice treated with 50 ng of CGRP alone or in combination with hCG, testes were at a position similar to those in controls. Furthermore, testicular descent was analyzed in relation to testicular weight, and we found that significantly smaller testes per gram of body weight than those of controls were at a significantly lower position compared to those of controls. Our data demonstrate that CGRP had no effect on postnatal testicular descent and that there is no relationship between postnatal descent and testicular weight.

Air traffic management evaluation tool

NASA Technical Reports Server (NTRS)

Sridhar, Banavar (Inventor); Chatterji, Gano Broto (Inventor); Schipper, John F. (Inventor); Bilimoria, Karl D. (Inventor); Grabbe, Shon (Inventor); Sheth, Kapil S. (Inventor)

2012-01-01

Methods for evaluating and implementing air traffic management tools and approaches for managing and avoiding an air traffic incident before the incident occurs. A first system receives parameters for flight plan configurations (e.g., initial fuel carried, flight route, flight route segments followed, flight altitude for a given flight route segment, aircraft velocity for each flight route segment, flight route ascent rate, flight route descent route, flight departure site, flight departure time, flight arrival time, flight destination site and/or alternate flight destination site), flight plan schedule, expected weather along each flight route segment, aircraft specifics, airspace (altitude) bounds for each flight route segment, navigational aids available. The invention provides flight plan routing and direct routing or wind optimal routing, using great circle navigation and spherical Earth geometry. The invention provides for aircraft dynamics effects, such as wind effects at each altitude, altitude changes, airspeed changes and aircraft turns to provide predictions of aircraft trajectory (and, optionally, aircraft fuel use). A second system provides several aviation applications using the first system. Several classes of potential incidents are analyzed and averted, by appropriate change en route of one or more parameters in the flight plan configuration, as provided by a conflict detection and resolution module and/or traffic flow management modules. These applications include conflict detection and resolution, miles-in trail or minutes-in-trail aircraft separation, flight arrival management, flight re-routing, weather prediction and analysis and interpolation of weather variables based upon sparse measurements. The invention combines these features to provide an aircraft monitoring system and an aircraft user system that interact and negotiate changes with each other.

Transformable descent vehicles

NASA Astrophysics Data System (ADS)

Pichkhadze, K. M.; Finchenko, V. S.; Aleksashkin, S. N.; Ostreshko, B. A.

2016-12-01

This article presents some types of planetary descent vehicles, the shape of which varies in different flight phases. The advantages of such vehicles over those with unchangeable form (from launch to landing) are discussed. It is shown that the use of transformable descent vehicles widens the scope of possible tasks to solve.

43 CFR 10.14 - Lineal descent and cultural affiliation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... evidence sufficient to: (i) Establish the identity and cultural characteristics of the earlier group, (ii... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Lineal descent and cultural affiliation... GRAVES PROTECTION AND REPATRIATION REGULATIONS General § 10.14 Lineal descent and cultural affiliation...

43 CFR 10.14 - Lineal descent and cultural affiliation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... evidence sufficient to: (i) Establish the identity and cultural characteristics of the earlier group, (ii... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Lineal descent and cultural affiliation... GRAVES PROTECTION AND REPATRIATION REGULATIONS General § 10.14 Lineal descent and cultural affiliation...

An Examination of the Mediating Effect of Acculturation on the Relationship between Parenting Style, Academic Experience, and Resilience among Second and Third Generations West Indian College Students and Their Families

ERIC Educational Resources Information Center

Greene, Makeda Jacqueline

2017-01-01

With the increase of West Indian families of African descent acculturating into new communities and cultivating spaces for their cultures and customs to flourish, there is an increased significance for continued quantitative analyses to examine the cultural patterns, values and practices that take place within the West Indian familial structures…

Thermo-Physics Technical Note No. 60: thermal analysis of SNAP 10A reactor core during atmospheric reentry and resulting core disintegration and fuel element separation

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

Mouradian, E.M.

1966-02-16

A thermal analysis is carried out to determine the temperature distribution throughout a SNAP 10A reactor core, particularly in the vicinity of the grid plates, during atmospheric reentry. The transient temperatue distribution of the grid plate indicates when sufficient melting occurs so that fuel elements are free to be released and continue their descent individually.

EVA Suits Arrival

NASA Image and Video Library

2002-01-01

Extravehicular Activity (EVA) suits packed inside containers arrive at the Space Station Processing Facility from Johnson Space Center in Texas. The suits will be used by STS-117 crew members to perform several spacewalks during the mission. The mission payload aboard Space Shuttle Atlantis is the S3/S4 integrated truss structure, along with a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the International Space Station.

Altair Descent and Ascent Reference Trajectory Design and Initial Dispersion Analyses

NASA Technical Reports Server (NTRS)

Kos, Larry D.; Polsgrove, Tara T.; Sostaric, Ronald r.; Braden, Ellen M.; Sullivan, Jacob J.; Lee, Thanh T.

2010-01-01

The Altair Lunar Lander is the linchpin in the Constellation Program (CxP) for human return to the Moon. Altair is delivered to low Earth orbit (LEO) by the Ares V heavy lift launch vehicle, and after subsequent docking with Orion in LEO, the Altair/Orion stack is delivered through translunar injection (TLI). The Altair/Orion stack separating from the Earth departure stage (EDS) shortly after TLI and continues the flight to the Moon as a single stack. Altair performs the lunar orbit insertion (LOI) maneuver, targeting a 100-km circular orbit. This orbit will be a polar orbit for missions landing near the lunar South Pole. After spending nearly 24 hours in low lunar orbit (LLO), the lander undocks from Orion and performs a series of small maneuvers to set up for descending to the lunar surface. This descent begins with a small deorbit insertion (DOI) maneuver, putting the lander on an orbit that has a perilune of 15.24 km (50,000 ft), the altitude where the actual powered descent initiation (PDI) commences. At liftoff from Earth, Altair has a mass of 45 metric tons (mt). However after LOI (without Orion attached), the lander mass is slightly less than 33 mt at PDI. The lander currently has a single descent module main engine, with TBD lb(sub f) thrust (TBD N), providing a thrust-to-weight ratio of approximately TBD Earth g's at PDI. LDAC-3 (Lander design and analysis cycle #3) is the most recently closed design sizing and mass properties iteration. Upgrades for loss of crew (LDAC-2) and loss of mission (LDAC-3) have been incorporated into the lander baseline design (and its Master Equipment List). Also, recently, Altair has been working requirements analyses (LRAC-1). All nominal data here are from the LDAC-3 analysis cycle. All dispersions results here are from LRAC-1 analyses.

Fuel-Efficient Descent and Landing Guidance Logic for a Safe Lunar Touchdown

NASA Technical Reports Server (NTRS)

Lee, Allan Y.

2011-01-01

The landing of a crewed lunar lander on the surface of the Moon will be the climax of any Moon mission. At touchdown, the landing mechanism must absorb the load imparted on the lander due to the vertical component of the lander's touchdown velocity. Also, a large horizontal velocity must be avoided because it could cause the lander to tip over, risking the life of the crew. To be conservative, the worst-case lander's touchdown velocity is always assumed in designing the landing mechanism, making it very heavy. Fuel-optimal guidance algorithms for soft planetary landing have been studied extensively. In most of these studies, the lander is constrained to touchdown with zero velocity. With bounds imposed on the magnitude of the engine thrust, the optimal control solutions typically have a "bang-bang" thrust profile: the thrust magnitude "bangs" instantaneously between its maximum and minimum magnitudes. But the descent engine might not be able to throttle between its extremes instantaneously. There is also a concern about the acceptability of "bang-bang" control to the crew. In our study, the optimal control of a lander is formulated with a cost function that penalizes both the touchdown velocity and the fuel cost of the descent engine. In this formulation, there is not a requirement to achieve a zero touchdown velocity. Only a touchdown velocity that is consistent with the capability of the landing gear design is required. Also, since the nominal throttle level for the terminal descent sub-phase is well below the peak engine thrust, no bound on the engine thrust is used in our formulated problem. Instead of bangbang type solution, the optimal thrust generated is a continuous function of time. With this formulation, we can easily derive analytical expressions for the optimal thrust vector, touchdown velocity components, and other system variables. These expressions provide insights into the "physics" of the optimal landing and terminal descent maneuver. These insights could help engineers to achieve a better "balance" between the conflicting needs of achieving a safe touchdown velocity, a low-weight landing mechanism, low engine fuel cost, and other design goals. In comparing the computed optimal control results with the preflight landing trajectory design of the Apollo-11 mission, we noted interesting similarities between the two missions.

Overview of the Phoenix Entry, Descent and Landing System

NASA Technical Reports Server (NTRS)

Grover, Rob

2005-01-01

A viewgraph presentation on the entry, descent and landing system of Phoenix is shown. The topics include: 1) Phoenix Mission Goals; 2) Payload; 3) Aeroshell/Entry Comparison; 4) Entry Trajectory Comparison; 5) Phoenix EDL Timeline; 6) Hypersonic Phase; 7) Parachute Phase; 8) Terminal Descent Phase; and 9) EDL Communications.

Ascent/Descent Software

NASA Technical Reports Server (NTRS)

Brown, Charles; Andrew, Robert; Roe, Scott; Frye, Ronald; Harvey, Michael; Vu, Tuan; Balachandran, Krishnaiyer; Bly, Ben

2012-01-01

The Ascent/Descent Software Suite has been used to support a variety of NASA Shuttle Program mission planning and analysis activities, such as range safety, on the Integrated Planning System (IPS) platform. The Ascent/Descent Software Suite, containing Ascent Flight Design (ASC)/Descent Flight Design (DESC) Configuration items (Cis), lifecycle documents, and data files used for shuttle ascent and entry modeling analysis and mission design, resides on IPS/Linux workstations. A list of tools in Navigation (NAV)/Prop Software Suite represents tool versions established during or after the IPS Equipment Rehost-3 project.

Steepest descent method implementation on unconstrained optimization problem using C++ program

NASA Astrophysics Data System (ADS)

Napitupulu, H.; Sukono; Mohd, I. Bin; Hidayat, Y.; Supian, S.

2018-03-01

Steepest Descent is known as the simplest gradient method. Recently, many researches are done to obtain the appropriate step size in order to reduce the objective function value progressively. In this paper, the properties of steepest descent method from literatures are reviewed together with advantages and disadvantages of each step size procedure. The development of steepest descent method due to its step size procedure is discussed. In order to test the performance of each step size, we run a steepest descent procedure in C++ program. We implemented it to unconstrained optimization test problem with two variables, then we compare the numerical results of each step size procedure. Based on the numerical experiment, we conclude the general computational features and weaknesses of each procedure in each case of problem.

Dynamics of the Venera 13 and 14 descent modules in the parachute segment of descent

NASA Astrophysics Data System (ADS)

Vishniak, A. A.; Kariagin, V. P.; Kovtunenko, V. M.; Kotov, B. B.; Kuznetsov, V. V.; Lopatkin, A. I.; Perov, O. V.; Pichkhadze, K. M.; Rysev, O. V.

1983-05-01

The parachute system for the Venera 13 and 14 descent modules was designed to assure the prescribed duration of descent in the Venus cloud layer as well as the separation of heat-shield elements from the module. A mathematical model is developed which makes possible a numerical analysis of the dynamics of the module-parachute system with allowance for parachute inertia, atmospheric turbulence, the means by which the parachute is attachead to the module, and the elasticity and damping of the suspended system. A formula is derived for determining the period of oscillations of the module in the parachute segment of descent. A comparison of theoretical and experimental results shows that this formula can be used in the design calculations, especially at the early stage of module development.

Tracer-Based Determination of Vortex Descent in the 1999-2000 Arctic Winter

NASA Technical Reports Server (NTRS)

Greenblatt, Jeffery B.; Jost, Hans-Juerg; Loewenstein, Max; Podolske, James R.; Hurst, Dale F.; Elkins, James W.; Schauffler, Sue M.; Atlas, Elliot L.; Herman, Robert L.; Webster, Christopher R.

2001-01-01

A detailed analysis of available in situ and remotely sensed N2O and CH4 data measured in the 1999-2000 winter Arctic vortex has been performed in order to quantify the temporal evolution of vortex descent. Differences in potential temperature (theta) among balloon and aircraft vertical profiles (an average of 19-23 K on a given N2O or CH4 isopleth) indicated significant vortex inhomogeneity in late fall as compared with late winter profiles. A composite fall vortex profile was constructed for November 26, 1999, whose error bars encompassed the observed variability. High-latitude, extravortex profiles measured in different years and seasons revealed substantial variability in N2O and CH4 on theta surfaces, but all were clearly distinguishable from the first vortex profiles measured in late fall 1999. From these extravortex-vortex differences, we inferred descent prior to November 26: 397+/-15 K (1sigma) at 30 ppbv N2O and 640 ppbv CH4, and 28+/-13 K above 200 ppbv N2O and 1280 ppbv CH4. Changes in theta were determined on five N2O and CH4 isopleths from November 26 through March 12, and descent rates were calculated on each N2O isopleth for several time intervals. The maximum descent rates were seen between November 26 and January 27: 0.82+/-0.20 K/day averaged over 50-250 ppbv N2O. By late winter (February 26-March 12), the average rate had decreased to 0.10+/-0.25 K/day. Descent rates also decreased with increasing N2O; the winter average (November 26-March 5) descent rate varied from 0.75+/-0.10 K/day at 50 ppbv to 0.40+/-0.11 K/day at 250 ppbv. Comparison of these results with observations and models of descent in prior years showed very good overall agreement. Two models of the 1999-2000 vortex descent, SLIMCAT and REPROBUS, despite theta offsets with respect to observed profiles of up to 20 K on most tracer isopleths, produced descent rates that agreed very favorably with the inferred rates from observation.

Immediate effects of a distal gait modification during stair descent in individuals with patellofemoral pain.

PubMed

Aliberti, Sandra; Mezêncio, Bruno; Amadio, Alberto Carlos; Serrão, Julio Cerca; Mochizuki, Luis

2018-05-23

Knee pain during stair managing is a common complaint among individuals with PFP and can negatively affect their activities of daily living. Gait modification programs can be used to decrease patellofemoral pain. Immediate effects of a stair descent distal gait modification session that intended to emphasize forefoot landing during stair descent are described in this study. To analyze the immediate effects of a distal gait modification session on lower extremity movements and intensity of pain in women with patellofemoral pain during stair descent. Nonrandomized controlled trial. Sixteen women with patellofemoral pain were allocated into two groups: (1) Gait Modification Group (n = 8); and 2) Control Group (n = 8). The intensity of pain (visual analog scale) and kinematics of knee, ankle, and forefoot (multi-segmental foot model) during stair descent were assessed before and after the intervention. After the gait modification session, there was an increase of forefoot eversion and ankle plantarflexion as well as a decrease of knee flexion. An immediate decrease in patellofemoral pain intensity during stair descent was also observed. The distal gait modification session changed the lower extremity kinetic chain strategy of movement, increasing foot and ankle movement contribution and decreasing knee contribution to the task. An immediate decrease in patellofemoral pain intensity during stair descent was also observed. To emphasize forefoot landing may be a useful intervention to immediately relieve pain in patients with patellofemoral pain during stair descent. Clinical studies are needed to verify the gait modification session effects in medium and long terms.

Human Scleral Structural Stiffness Increases More Rapidly With Age in Donors of African Descent Compared to Donors of European Descent

PubMed Central

Fazio, Massimo A.; Grytz, Rafael; Morris, Jeffrey S.; Bruno, Luigi; Girkin, Christopher A.; Downs, J. Crawford

2014-01-01

Purpose. We tested the hypothesis that the variation of peripapillary scleral structural stiffness with age is different in donors of European (ED) and African (AD) descent. Methods. Posterior scleral shells from normal eyes from donors of European (n = 20 pairs; previously reported) and African (n = 9 pairs) descent aged 0 and 90 years old were inflation tested within 48 hours post mortem. Scleral shells were pressurized from 5 to 45 mm Hg and the full-field, 3-dimensional (3D) deformation of the outer surface was recorded at submicrometric accuracy using speckle interferometry (ESPI). Mean maximum principal (tensile) strain of the peripapillary and midperipheral regions surrounding the optic nerve head (ONH) were fit using a functional mixed effects model that accounts for intradonor variability, same-race correlation, and spatial autocorrelation to estimate the effect of race on the age-related changes in mechanical scleral strain. Results. Mechanical tensile strain significantly decreased with age in the peripapillary sclera in the African and European descent groups (P < 0.001), but the age-related stiffening was significantly greater in the African descent group (P < 0.05). Maximum principal strain in the peripapillary sclera was significantly higher than in the midperipheral sclera for both ethnic groups. Conclusions. The sclera surrounding the ONH stiffens more rapidly with age in the African descent group compared to the European group. Stiffening of the peripapillary sclera with age may be related to the higher prevalence of glaucoma in the elderly and persons of African descent. PMID:25237162

Human scleral structural stiffness increases more rapidly with age in donors of African descent compared to donors of European descent.

PubMed

Fazio, Massimo A; Grytz, Rafael; Morris, Jeffrey S; Bruno, Luigi; Girkin, Christopher A; Downs, J Crawford

2014-09-18

We tested the hypothesis that the variation of peripapillary scleral structural stiffness with age is different in donors of European (ED) and African (AD) descent. Posterior scleral shells from normal eyes from donors of European (n = 20 pairs; previously reported) and African (n = 9 pairs) descent aged 0 and 90 years old were inflation tested within 48 hours post mortem. Scleral shells were pressurized from 5 to 45 mm Hg and the full-field, 3-dimensional (3D) deformation of the outer surface was recorded at submicrometric accuracy using speckle interferometry (ESPI). Mean maximum principal (tensile) strain of the peripapillary and midperipheral regions surrounding the optic nerve head (ONH) were fit using a functional mixed effects model that accounts for intradonor variability, same-race correlation, and spatial autocorrelation to estimate the effect of race on the age-related changes in mechanical scleral strain. Mechanical tensile strain significantly decreased with age in the peripapillary sclera in the African and European descent groups (P < 0.001), but the age-related stiffening was significantly greater in the African descent group (P < 0.05). Maximum principal strain in the peripapillary sclera was significantly higher than in the midperipheral sclera for both ethnic groups. The sclera surrounding the ONH stiffens more rapidly with age in the African descent group compared to the European group. Stiffening of the peripapillary sclera with age may be related to the higher prevalence of glaucoma in the elderly and persons of African descent. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Latin American Immigrant Women and Intergenerational Sex Education

ERIC Educational Resources Information Center

Alcalde, Maria Cristina; Quelopana, Ana Maria

2013-01-01

People of Latin American descent make up the largest and fastest-growing minority group in the USA. Rates of pregnancy, childbirth, and sexually transmitted infections among people of Latin American descent are higher than among other ethnic groups. This paper builds on research that suggests that among families of Latin American descent, mothers…

Analysis of foot clearance in firefighters during ascent and descent of stairs.

PubMed

Kesler, Richard M; Horn, Gavin P; Rosengren, Karl S; Hsiao-Wecksler, Elizabeth T

2016-01-01

Slips, trips, and falls are a leading cause of injury to firefighters with many injuries occurring while traversing stairs, possibly exaggerated by acute fatigue from firefighting activities and/or asymmetric load carriage. This study examined the effects that fatigue, induced by simulated firefighting activities, and hose load carriage have on foot clearance while traversing stairs. Landing and passing foot clearances for each stair during ascent and descent of a short staircase were investigated. Clearances decreased significantly (p < 0.05) post-exercise for nine of 12 ascent parameters and increased for two of eight descent parameters. Load carriage resulted in significantly decreased (p < 0.05) clearance over three ascent parameters, and one increase during descent. Decreased clearances during ascent caused by fatigue or load carriage may result in an increased trip risk. Increased clearances during descent may suggest use of a compensation strategy to ensure stair clearance or an increased risk of over-stepping during descent. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Toward a Caribbean psychology: an African-centered approach.

PubMed

Sutherland, Marcia Elizabeth

2011-01-01

Although the Americas and Caribbean region are purported to comprise different ethnic groups, this article’s focus is on people of African descent, who represent the largest ethnic group in many countries. The emphasis on people of African descent is related to their family structure, ethnic identity, cultural, psychohistorical, and contemporary psychosocial realities. This article discusses the limitations of Western psychology for theory, research, and applied work on people of African descent in the Americas and Caribbean region. In view of the adaptations that some people of African descent have made to slavery, colonialism, and more contemporary forms of cultural intrusions, it is argued that when necessary, notwithstanding Western psychology’s limitations, Caribbean psychologists should reconstruct mainstream psychology to address the psychological needs of these Caribbean people. The relationship between theory and psychological interventions for the optimal development of people of African descent is emphasized throughout this article. In this regard, the African-centered and constructionist viewpoint is argued to be of utility in addressing the psychological growth and development of people of African descent living in the Americas and Caribbean region.

Establishing and Validating Empirically-Based Ground Truth Criteria for Seismic Events Recorded on Regional Networks (Postprint)

DTIC Science & Technology

2011-12-30

which data sets containing GT0 events (explosions and mine tremors) are available, local crustal structure is well known, and hand-picked arrival...available, local crustal structure is well known, and hand-picked arrival times have been obtained. Boomer et al. (2010) describes the development of...local criteria for the simple crustal structure of the Archean Kaapvaal Craton in southern Africa. Continuing the development of local criteria in

Ascent/descent ancillary data production user's guide

NASA Technical Reports Server (NTRS)

Brans, H. R.; Seacord, A. W., II; Ulmer, J. W.

1986-01-01

The Ascent/Descent Ancillary Data Product, also called the A/D BET because it contains a Best Estimate of the Trajectory (BET), is a collection of trajectory, attitude, and atmospheric related parameters computed for the ascent and descent phases of each Shuttle Mission. These computations are executed shortly after the event in a post-flight environment. A collection of several routines including some stand-alone routines constitute what is called the Ascent/Descent Ancillary Data Production Program. A User's Guide for that program is given. It is intended to provide the reader with all the information necessary to generate an Ascent or a Descent Ancillary Data Product. It includes descriptions of the input data and output data for each routine, and contains explicit instructions on how to run each routine. A description of the final output product is given.

Real-time Upstream Monitoring System: Using ACE Data to Predict the Arrival of Interplanetary Shocks

NASA Astrophysics Data System (ADS)

Donegan, M. M.; Wagstaff, K. L.; Ho, G. C.; Vandegriff, J.

2003-12-01

We have developed an algorithm to predict Earth arrival times for interplanetary (IP) shock events originating at the Sun. Our predictions are generated from real-time data collected by the Electron, Proton, and Alpha Monitor (EPAM) instrument on NASA's Advanced Composition Explorer (ACE) spacecraft. The high intensities of energetic ions that occur prior to and during an IP shock pose a radiation hazard to astronauts as well as to electronics in Earth orbit. The potential to predict such events is based on characteristic signatures in the Energetic Storm Particle (ESP) event ion intensities which are often associated with IP shocks. We have previously reported on the development and implementation of an algorithm to forecast the arrival of ESP events. Historical ion data from ACE/EPAM was used to train an artificial neural network which uses the signature of an approaching event to predict the time remaining until the shock arrives. Tests on the trained network have been encouraging, with an average error of 9.4 hours for predictions made 24 hours in advance, and an reduced average error of 4.9 hours when the shock is 12 hours away. The prediction engine has been integrated into a web-based system that uses real-time ACE/EPAM data provided by the NOAA Space Environment Center (http://sd-www.jhuapl.edu/UPOS/RISP/ index.html.) This system continually processes the latest ACE data, reports whether or not there is an impending shock, and predicts the time remaining until the shock arrival. Our predictions are updated every five minutes and provide significant lead-time, thereby supplying critical information that can be used by mission planners, satellite operations controllers, and scientists. We have continued to refine the prediction capabilities of this system; in addition to forecasting arrival times for shocks, we now provide confidence estimates for those predictions.

Baseline data from a planned RCT on attitudes to female genital cutting after migration: when are interventions justified?

PubMed Central

Johnsdotter, Sara; Selling, Katarina Ekholm; Källestål, Carina; Essén, Birgitta

2017-01-01

Objectives To present the primary outcomes from a baseline study on attitudes towards female genital cutting (FGC) after migration. Design Baseline data from a planned cluster randomised, controlled trial. Face-to-face interviews were used to collect questionnaire data in 2015. Based on our hypothesis that established Somalis could be used as facilitators of change among those newly arrived, data were stratified into years of residency in Sweden. Setting Sweden. Participants 372 Somali men and women, 206 newly arrived (0–4 years), 166 established (>4 years). Primary outcome measures Whether FGC is acceptable, preferred for daughter and should continue, specified on anatomical extent. Results The support for anatomical change of girls and women’s genitals ranged from 0% to 2% among established and from 4% to 8% among newly arrived. Among those supporting no anatomical change, 75%–83% among established and 53%–67% among newly arrived opposed all forms of FGC, with the remaining supporting pricking of the skin with no removal of tissue. Among newly arrived, 37% stated that pricking was acceptable, 39% said they wanted their daughter to be pricked and 26% reported they wanted pricking to continue being practised. Those who had lived in Sweden ≤ 2 years had highest odds of supporting FGC; thereafter, the opposition towards FGC increased over time after migration. Conclusion A majority of Somali immigrants, including those newly arrived, opposed all forms of FGC with increased opposition over time after migration. The majority of proponents of FGC supported pricking. We argue that it would have been unethical to proceed with the intervention as it, with this baseline, would have been difficult to detect a change in attitudes given that a majority opposed all forms of FGC together with the evidence that a strong attitude change is already happening. Therefore, we decided not to implement the planned intervention. Trial registration number Trial registration number NCT02335697;Pre-results. PMID:28801440

Cruise-Efficient Short Takeoff and Landing (CESTOL): Potential Impact on Air Traffic Operations

NASA Technical Reports Server (NTRS)

Couluris, G. J.; Signor, D.; Phillips, J.

2010-01-01

The National Aeronautics and Space Administration (NASA) is investigating technological and operational concepts for introducing Cruise-Efficient Short Takeoff and Landing (CESTOL) aircraft into a future US National Airspace System (NAS) civil aviation environment. CESTOL is an aircraft design concept for future use to increase capacity and reduce emissions. CESTOL provides very flexible takeoff, climb, descent and landing performance capabilities and a high-speed cruise capability. In support of NASA, this study is a preliminary examination of the potential operational impact of CESTOL on airport and airspace capacity and delay. The study examines operational impacts at a subject site, Newark Liberty Intemational Airport (KEWR), New Jersey. The study extends these KEWR results to estimate potential impacts on NAS-wide network traffic operations due to the introduction of CESTOL at selected major airports. These are the 34 domestic airports identified in the Federal Aviation Administration's Operational Evolution Plan (OEP). The analysis process uses two fast-time simulation tools to separately model local and NAS-wide air traffic operations using predicted flight schedules for a 24-hour study period in 2016. These tools are the Sen sis AvTerminal model and NASA's Airspace Concept Evaluation System (ACES). We use both to simulate conventional-aircraft-only and CESTOL-mixed-with-conventional-aircraft operations. Both tools apply 4-dimension trajectory modeling to simulate individual flight movement. The study applies AvTerminal to model traffic operations and procedures for en route and terminal arrival and departures to and from KEWR. These AvTerminal applications model existing arrival and departure routes and profiles and runway use configurations, with the assumption jet-powered, large-sized civil CESTOL aircraft use a short runway and standard turboprop arrival and departure procedures. With these rules, the conventional jet and CESTOL aircraft are procedurally separated from each other geographically and in altitude during tenninal airspace approach and departure operations, and each use a different arrival runway. AvTeminal implements its unique Focal-point Scheduling Process to sequence, space and delay aircraft to resolve spacing and overtake conflicts among flights in the airspace and airport system serving KEWR. This Process effectively models integrated arrival and departure operations. AvTerminal assesses acceptance rates and delay magnitude and causality at selected locations, including en route outer boundary fixes, tenninal airspace arrival and departure boundary fixes, terminal airspace arrival merge and departure diverge fixes, and runway landing and takeoff runways. The analysis compares the resulting capacity impacts, flight delays and delay sources between CESTOL and conventional KEWR operations. AvTerminal quantitative results showed that CESTOL has significant capability to increase airport arrival acceptance rates (35-40% at KEWR) by taking advantage of otherwise underused airspace and runways where available. The study extrapolates the AvTerminal-derived KEWR peak arrival and departure acceptance rates to estimate capacity parameter values for each of the OEP airports in the ACES modeling of traffic through the entire NAS network. The extrapolations of acceptance rates allow full, partial or no achievement of CESTOL capacity gains at an OEP airport as determined by assessments of the degree to which local procedures allow leveraging of CESTOL capabilities. These assessments consider each OEP airport's runway geometries, runway system configurations, airport and airspace operations, and potential CESTOL traffic loadings. The ACES modeling, simulates airport and airspace spacing constraints imposed by airport runway system, terminal and en route air traffic control and traffic flow management operations using airport acceptance rates representing conventional-aircraft-only and CESTOL-mixed operations. CEOL aircraft are assumed to have Mach 0.8, and alternatively Mach 0.7, cruise speeds to examine compatibility with conventional aircraft operations in common airspace. The ACES results provides estimates of CESTOL delay impact NAS-wide and at OEP airports due to changes in OEP airport acceptance rates and changes in en route airspace potential conflict rates. Preliminary results show meaningful nationwide delay reductions (20%) due to CESTOL operations at 34 major domestic airports.

Rotary Wing Deceleration Use on Titan

NASA Technical Reports Server (NTRS)

Young, Larry A.; Steiner, Ted J.

2011-01-01

Rotary wing decelerator (RWD) systems were compared against other methods of atmospheric deceleration and were determined to show significant potential for application to a system requiring controlled descent, low-velocity landing, and atmospheric research capability on Titan. Design space exploration and down-selection results in a system with a single rotor utilizing cyclic pitch control. Models were developed for selection of a RWD descent system for use on Titan and to determine the relationships between the key design parameters of such a system and the time of descent. The possibility of extracting power from the system during descent was also investigated.

Experimental Infrasound Studies in Nevada

NASA Astrophysics Data System (ADS)

Herrin, E. T.; Negraru, P. T.; Golden, P.; Williams, A.

2009-12-01

An experimental propagation study was carried out in Nevada in June 2009 on Julian days 173-177. During this field experiment we deployed 16 single channel digital infrasound recorders to monitor the munitions disposal activities near Hawthorne, NV. The sensors were deployed in a single line and placed approximately 12 km apart at distances ranging from 2 to 177 km. A four element semi-permanent infrasound array named FNIAR was installed approximately 154 km north of the detonation site in line with the individual temporary recorders. Tropospheric arrivals were observed during all days of the experiment, but during day 176 the observed arrivals had very large amplitudes. A large signal was observed at 58 km from the detonation site with amplitude as large as 4 Pascals, while at 94 km no signal was observed. At FNIAR the amplitude of the tropospheric arrival was 1 Pascal. During this day meteorological data acquired in the propagation path showed a strong jet stream to the north. On day 177 we were not able to identify tropospheric arrivals beyond 34 km, but at stations beyond 152 km we observed stratospheric arrivals. Continuous monitoring of these signals at FNIAR shows that stratospheric arrivals are the most numerous. In a two month period, from 06/15/2009 to 08/15/2009 there were 35 operational days at the Hawthorne disposal facility resulting in 212 explosions with known origin times. Based on the celerity values there were 115 explosions that have only stratospheric arrivals (celerities of 300-275 m/s), 72 explosions with both tropospheric (celerities above 330 m/s) and stratospheric arrivals, 20 explosions that were not detected and five explosions that have only tropospheric arrivals.

An Impacting Descent Probe for Europa and the Other Galilean Moons of Jupiter

NASA Astrophysics Data System (ADS)

Wurz, P.; Lasi, D.; Thomas, N.; Piazza, D.; Galli, A.; Jutzi, M.; Barabash, S.; Wieser, M.; Magnes, W.; Lammer, H.; Auster, U.; Gurvits, L. I.; Hajdas, W.

2017-08-01

We present a study of an impacting descent probe that increases the science return of spacecraft orbiting or passing an atmosphere-less planetary bodies of the solar system, such as the Galilean moons of Jupiter. The descent probe is a carry-on small spacecraft (<100 kg), to be deployed by the mother spacecraft, that brings itself onto a collisional trajectory with the targeted planetary body in a simple manner. A possible science payload includes instruments for surface imaging, characterisation of the neutral exosphere, and magnetic field and plasma measurement near the target body down to very low-altitudes ( 1 km), during the probe's fast ( km/s) descent to the surface until impact. The science goals and the concept of operation are discussed with particular reference to Europa, including options for flying through water plumes and after-impact retrieval of very-low altitude science data. All in all, it is demonstrated how the descent probe has the potential to provide a high science return to a mission at a low extra level of complexity, engineering effort, and risk. This study builds upon earlier studies for a Callisto Descent Probe for the former Europa-Jupiter System Mission of ESA and NASA, and extends them with a detailed assessment of a descent probe designed to be an additional science payload for the NASA Europa Mission.

Keepers of Our Stories

ERIC Educational Resources Information Center

Stasiuk, Glen

2010-01-01

Storytelling is an integral part of life for Indigenous Australians. Before the arrival of Europeans and continuing after; gathered around the campfire in the evening stories were and are still shared; passed from one generation to the next. In modern times, in addition to a continuing oral traditions, another method of storytelling has risen from…

Hair Breakage in Patients of African Descent: Role of Dermoscopy

PubMed Central

Quaresma, Maria Victória; Martinez Velasco, María Abril; Tosti, Antonella

2015-01-01

Dermoscopy represents a useful technique for the diagnosis and follow-up of hair and scalp disorders. To date, little has been published regarding dermoscopy findings of hair disorders in patients of African descent. This article illustrates how dermoscopy allows fast diagnosis of hair breakage due to intrinsic factors and chemical damage in African descent patients. PMID:27170942

Ethnic Identity and Acculturative Stress as Mediators of Depression in Students of Asian Descent

ERIC Educational Resources Information Center

Lantrip, Crystal; Mazzetti, Francesco; Grasso, Joseph; Gill, Sara; Miller, Janna; Haner, Morgynn; Rude, Stephanie; Awad, Germine

2015-01-01

This study underscored the importance of addressing the well-being of college students of Asian descent, because these students had higher rates of depression and lower positive feelings about their ethnic group compared with students of European descent, as measured by the Affirmation subscale of the Ethnic Identity Scale. Affirmation mediated…

Device for Lowering Mars Science Laboratory Rover to the Surface

NASA Technical Reports Server (NTRS)

2008-01-01

This is hardware for controlling the final lowering of NASA's Mars Science Laboratory rover to the surface of Mars from the spacecraft's hovering, rocket-powered descent stage.

The photo shows the bridle device assembly, which is about two-thirds of a meter, or 2 feet, from end to end, and has two main parts. The cylinder on the left is the descent brake. On the right is the bridle assembly, including a spool of nylon and Vectran cords that will be attached to the rover.

When pyrotechnic bolts fire to sever the rigid connection between the rover and the descent stage, gravity will pull the tethered rover away from the descent stage. The bridle or tether, attached to three points on the rover, will unspool from the bridle assembly, beginning from the larger-diameter portion of the spool at far right. The rotation rate of the assembly, hence the descent rate of the rover, will be governed by the descent brake. Inside the housing of that brake are gear boxes and banks of mechanical resistors engineered to prevent the bridle from spooling out too quickly or too slowly. The length of the bridle will allow the rover to be lowered about 7.5 meters (25 feet) while still tethered to the descent stage.

The Starsys division of SpaceDev Inc., Poway, Calif., provided the descent brake. NASA's Jet Propulsion Laboratory, Pasadena, Calif., built the bridle assembly. Vectran is a product of Kuraray Co. Ltd., Tokyo. JPL, a division of the California Institute of Technology, manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington.

Antarctic Polar Descent and Planetary Wave Activity Observed in ISAMS CO from April to July 1992

NASA Technical Reports Server (NTRS)

Allen, D. R.; Stanford, J. L.; Nakamura, N.; Lopez-Valverde, M. A.; Lopez-Puertas, M.; Taylor, F. W.; Remedios, J. J.

2000-01-01

Antarctic polar descent and planetary wave activity in the upper stratosphere and lower mesosphere are observed in ISAMS CO data from April to July 1992. CO-derived mean April-to-May upper stratosphere descent rates of 15 K/day (0.25 km/day) at 60 S and 20 K/day (0.33 km/day) at 80 S are compared with descent rates from diabatic trajectory analyses. At 60 S there is excellent agreement, while at 80 S the trajectory-derived descent is significantly larger in early April. Zonal wavenumber 1 enhancement of CO is observed on 9 and 28 May, coincident with enhanced wave 1 in UKMO geopotential height. The 9 May event extends from 40 to 70 km and shows westward phase tilt with height, while the 28 May event extends from 40 to 50 km and shows virtually no phase tilt with height.

The Uncertain Significance of Low Vitamin D levels in African Descent Populations: A Review of the Bone and Cardiometabolic Literature

PubMed Central

O'Connor, Michelle Y; Thoreson, Caroline K; Ramsey, Natalie L M; Ricks, Madia; Sumner, Anne E

2014-01-01

Vitamin D levels in people of African descent are often described as inadequate or deficient. Whether low vitamin D levels in people of African descent lead to compromised bone or cardiometabolic health is unknown. Clarity on this issue is essential because if clinically significant vitamin D deficiency is present, vitamin D supplementation is necessary. However, if vitamin D is metabolically sufficient, vitamin D supplementation could be wasteful of scarce resources and even harmful. In this review vitamin D physiology is described with a focus on issues specific to populations of African descent such as the influence of melanin on endogenous vitamin D production and lactose intolerance on the willingness of people to ingest vitamin D fortified foods. Then data on the relationship of vitamin D to bone and cardiometabolic health in people of African descent are evaluated. PMID:24267433

Descent Assisted Split Habitat Lunar Lander Concept

NASA Technical Reports Server (NTRS)

Mazanek, Daniel D.; Goodliff, Kandyce; Cornelius, David M.

2008-01-01

The Descent Assisted Split Habitat (DASH) lunar lander concept utilizes a disposable braking stage for descent and a minimally sized pressurized volume for crew transport to and from the lunar surface. The lander can also be configured to perform autonomous cargo missions. Although a braking-stage approach represents a significantly different operational concept compared with a traditional two-stage lander, the DASH lander offers many important benefits. These benefits include improved crew egress/ingress and large-cargo unloading; excellent surface visibility during landing; elimination of the need for deep-throttling descent engines; potentially reduced plume-surface interactions and lower vertical touchdown velocity; and reduced lander gross mass through efficient mass staging and volume segmentation. This paper documents the conceptual study on various aspects of the design, including development of sortie and outpost lander configurations and a mission concept of operations; the initial descent trajectory design; the initial spacecraft sizing estimates and subsystem design; and the identification of technology needs

Descent graphs in pedigree analysis: applications to haplotyping, location scores, and marker-sharing statistics.

PubMed Central

Sobel, E.; Lange, K.

1996-01-01

The introduction of stochastic methods in pedigree analysis has enabled geneticists to tackle computations intractable by standard deterministic methods. Until now these stochastic techniques have worked by running a Markov chain on the set of genetic descent states of a pedigree. Each descent state specifies the paths of gene flow in the pedigree and the founder alleles dropped down each path. The current paper follows up on a suggestion by Elizabeth Thompson that genetic descent graphs offer a more appropriate space for executing a Markov chain. A descent graph specifies the paths of gene flow but not the particular founder alleles traveling down the paths. This paper explores algorithms for implementing Thompson's suggestion for codominant markers in the context of automatic haplotyping, estimating location scores, and computing gene-clustering statistics for robust linkage analysis. Realistic numerical examples demonstrate the feasibility of the algorithms. PMID:8651310

KSC-2012-4254

NASA Image and Video Library

2012-08-03

CAPE CANAVERAL, Fla. – At NASA’s Kennedy Space Center in Florida, NASA Administrator Charles Bolden, left, joins Dr. Jon Olansen, Morpheus project manager, in the control room at the Shuttle Landing Facility for the first tethered flight of the Morpheus lander. After undergoing testing at Johnson Space Center in Houston for nearly a year, Morpheus arrived at Kennedy on July 27 to begin about three months of tests. A field, replete with boulders, rocks, slopes, craters and hazards to avoid, was created at the north end of Kennedy's runway to provide a realistic landscape for test flights of the lander. Morpheus utilizes autonomous landing and hazard avoidance technology, or ALHAT, to navigate to a safe landing site during its descent. Project Morpheus is one of 20 small projects comprising the Advanced Exploration Systems, or AES, program in NASA's Human Exploration and Operations Mission Directorate. AES projects pioneer new approaches for rapidly developing prototype systems, demonstrating key capabilities and validating operational concepts for future human missions beyond Earth orbit. For more information on Project Morpheus, visit http://www.nasa.gov/centers/johnson/exploration/morpheus/index.html. Photo credit: NASA/Kim Shiflett

KSC-2012-4253

NASA Image and Video Library

2012-08-03

CAPE CANAVERAL, Fla. – At NASA’s Kennedy Space Center in Florida, NASA Administrator Charles Bolden joins Morpheus project manager Dr. Jon Olansen, pointing at monitor, in the control room at the Shuttle Landing Facility for the first tethered flight of the Morpheus lander. After undergoing testing at Johnson Space Center in Houston for nearly a year, Morpheus arrived at Kennedy on July 27 to begin about three months of tests. A field, replete with boulders, rocks, slopes, craters and hazards to avoid, was created at the north end of Kennedy's runway to provide a realistic landscape for test flights of the lander. Morpheus utilizes autonomous landing and hazard avoidance technology, or ALHAT, to navigate to a safe landing site during its descent. Project Morpheus is one of 20 small projects comprising the Advanced Exploration Systems, or AES, program in NASA's Human Exploration and Operations Mission Directorate. AES projects pioneer new approaches for rapidly developing prototype systems, demonstrating key capabilities and validating operational concepts for future human missions beyond Earth orbit. For more information on Project Morpheus, visit http://www.nasa.gov/centers/johnson/exploration/morpheus/index.html. Photo credit: NASA/Kim Shiflett

Inherent smoothness of intensity patterns for intensity modulated radiation therapy generated by simultaneous projection algorithms

NASA Astrophysics Data System (ADS)

Xiao, Ying; Michalski, Darek; Censor, Yair; Galvin, James M.

2004-07-01

The efficient delivery of intensity modulated radiation therapy (IMRT) depends on finding optimized beam intensity patterns that produce dose distributions, which meet given constraints for the tumour as well as any critical organs to be spared. Many optimization algorithms that are used for beamlet-based inverse planning are susceptible to large variations of neighbouring intensities. Accurately delivering an intensity pattern with a large number of extrema can prove impossible given the mechanical limitations of standard multileaf collimator (MLC) delivery systems. In this study, we apply Cimmino's simultaneous projection algorithm to the beamlet-based inverse planning problem, modelled mathematically as a system of linear inequalities. We show that using this method allows us to arrive at a smoother intensity pattern. Including nonlinear terms in the simultaneous projection algorithm to deal with dose-volume histogram (DVH) constraints does not compromise this property from our experimental observation. The smoothness properties are compared with those from other optimization algorithms which include simulated annealing and the gradient descent method. The simultaneous property of these algorithms is ideally suited to parallel computing technologies.

Long Awaited Fundamental Measurement of the Martian Upper Atmosphere from the Langmuir Probe and Waves Instrument on the MAVEN Mission.

NASA Astrophysics Data System (ADS)

Andersson, Laila; Andrews, David; Ergun, Bob; Delory, Greg; Morooka, Michiko; Fowler, Chris; McEnulty, Tess; Weber, Tristan; Eriksson, Anders; Malaspina, David; Crary, Frank; Mitchell, David; McFadden, Jim; Halekas, Jasper; Larson, Davin; Connerney, Jack; Espley, Jared; Eparvies, Frank

2015-04-01

Electron temperature and density are critical quantities in understanding an upper atmosphere. Approximately 40 years ago, the Viking landers reached the Martian surface, measuring the first (and only) two temperature profiles during it's descent. With the MAVEN mission arriving at Mars details of the Martian ionosphere can agin be studied by a complete plasma package. This paper investigates the first few months of data from the MAVEN mission when the orbit is below 500 km and around the northern hemisphere's terminator. The fo-cus of this presentation is on the different measure-ments that the Langmuir probe and Waves (LPW) in-strument is making on the MAVEN mission. Some of the LPW highlights that will be presented: (a) the long awaited new the electron temperature profiles; (b) the structures observed on the nightside ionosphere; (c) wave-particle insteractions observed below 500 km; and (d) the observed dusty environment at Mars. This presentation is supported by measurements from the other Particle and Fileds (PF) measurements on MAVEN.

Deep Space 2: The Mars Microprobe Mission

NASA Astrophysics Data System (ADS)

Smrekar, Suzanne; Catling, David; Lorenz, Ralph; Magalhães, Julio; Moersch, Jeffrey; Morgan, Paul; Murray, Bruce; Presley-Holloway, Marsha; Yen, Albert; Zent, Aaron; Blaney, Diana

The Mars Microprobe Mission will be the second of the New Millennium Program's technology development missions to planetary bodies. The mission consists of two penetrators that weigh 2.4 kg each and are being carried as a piggyback payload on the Mars Polar Lander cruise ring. The spacecraft arrive at Mars on December 3, 1999. The two identical penetrators will impact the surface at ~190 m/s and penetrate up to 0.6 m. They will land within 1 to 10 km of each other and ~50 km from the Polar Lander on the south polar layered terrain. The primary objective of the mission is to demonstrate technologies that will enable future science missions and, in particular, network science missions. A secondary goal is to acquire science data. A subsurface evolved water experiment and a thermal conductivity experiment will estimate the water content and thermal properties of the regolith. The atmospheric density, pressure, and temperature will be derived using descent deceleration data. Impact accelerometer data will be used to determine the depth of penetration, the hardness of the regolith, and the presence or absence of 10 cm scale layers.

Dynamical Evolution of the Inner Heliosphere Approaching Solar Activity Maximum: Interpreting Ulysses Observations Using a Global MHD Model. Appendix 1

NASA Technical Reports Server (NTRS)

Riley, Pete; Mikic, Z.; Linker, J. A.

2003-01-01

In this study we describe a series of MHD simulations covering the time period from 12 January 1999 to 19 September 2001 (Carrington Rotation 1945 to 1980). This interval coincided with: (1) the Sun s approach toward solar maximum; and (2) Ulysses second descent to the southern polar regions, rapid latitude scan, and arrival into the northern polar regions. We focus on the evolution of several key parameters during this time, including the photospheric magnetic field, the computed coronal hole boundaries, the computed velocity profile near the Sun, and the plasma and magnetic field parameters at the location of Ulysses. The model results provide a global context for interpreting the often complex in situ measurements. We also present a heuristic explanation of stream dynamics to describe the morphology of interaction regions at solar maximum and contrast it with the picture that resulted from Ulysses first orbit, which occurred during more quiescent solar conditions. The simulation results described here are available at: http://sun.saic.com.

KSC-07pd1373

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- The shuttle training aircraft, or STA, with STS-117 Commander Frederick Sturckow and Pilot Lee Archambault in the cockpit begins to taxi to the runway at KSC's Shuttle Landing Facility. Sturckow and Archambault will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

KSC-07pd1374

NASA Image and Video Library

2007-06-05

KENNEDY SPACE CENTER, FLA. -- It's wheels up for the shuttle training aircraft, or STA, after takeoff from KSC's Shuttle Landing Facility with STS-117 Commander Frederick Sturckow and Pilot Lee Archambault in the cockpit. Sturckow and Archambault will be making practice landings in the STA, which is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. STS-117 is scheduled to launch at 7:38 p.m. June 8. During the 11-day mission and three spacewalks, the crew will work with flight controllers at NASA's Johnson Space Center in Houston to install the 17-ton segment on the station's girder-like truss and deploy the set of solar arrays, S3/S4. The mission will increase the space station's power capability in preparation for the arrival of new science modules from the European and Japanese space agencies. Photo credit: NASA/Kim Shiflett

Observations and modelling of the boundary layer using remotely piloted aircraft

NASA Astrophysics Data System (ADS)

Cayez, Gregoire; Dralet, Jean-Philippe; Seity, Yann; Momboisse, Geraud; Hattenberger, Gautier; Bronz, Murat; Roberts, Greg

2014-05-01

Over the past decade, the scientific community considers the RPAS (remotely piloted aircraft system) as a tool which can help to improve their knowledge of climate and atmospheric phenomena. RPAS equipped with instruments can now conduct measurements in areas that are too hazardous or remote for a manned plane. RPAS are especially adapted system for observing the atmospheric boundary layer processes at high vertical and temporal resolution. The main objectives of VOLTIGE (Vecteur d'Observation de La Troposphère pour l'Investigation et la Gestion de l'Environnement) are to study the life cycle of fog with micro-RPAS, encourage direct participation of the students on the advancement and development of novel observing systems, and assess the feasibility of deploying RPAS in Météo-France's operational network. The instrumented RPAS flights successfully observed the evolution of small-scale meteorological events. Before the arrival of the warm pseudo-front, profiles show a temperature inversion of a hundred meters, which overlaps a cold and wet atmospheric layer. Subsequent profiles show the combination of the arrival of a marine air mass as well as the arrival of a higher level warm pseudo-front. A third case study characterizes the warm sector of the disturbance. Two distinct air masses are visible on the vertical profiles, and show a dry air above an air almost saturated and slightly colder. The temperature and the relative humidity profiles show < 1 meter vertical resolution with a difference between ascent and descent profiles within ± 0.5°C and ± 6 % RH. These results comply with the Météo-France standard limits of quality control. The RPAS profiles were compared with those of the Arome forecast model (an operational model at Météo France). The temperature and wind in the Arome model profiles generally agree with those of the RPAS (less for relative humidity profiles). The Arome model also suggests transitions between air masses occurred at a higher level than those measured by RPAS. These results suggest that forecast models may be improved using high resolution and frequent in-situ measurements.

JPL-20180307-INSIGHf-0001-Mars InSight Arrives at Vandenberg Air Force Base

NASA Image and Video Library

2018-03-07

NASA's InSight spacecraft arrived at Vandenberg Air Force Base, California, to begin final preparations for launch. InSight will be the first mission to look deep beneath the Martian surface, studying the planet's interior by listening for marsquakes and measuring its heat output. It will be the first planetary spacecraft to launch from this west coast launch facility. The launch period for InSight opens May 5, 2018 and continues through June 8, 2018.

Pulmonary paragonimiasis in an immigrant from Laos.

PubMed

Brown, R W; Clarke, R J; Denham, I; Trembath, P W

A chest X-ray film, taken in a refugee camp in Thailand six months before a 25-year-old Laotian farmer arrived in Australia, demonstrated lesions which were assumed to be tubercular. Despite antituberculous chemotherapy, the lesions continued to grow. On the man's arrival in Australia, cytological examination of bronchial washings showed the presence of numerous Paragonimus ova, and the patient received treatment with praziquantel. Paragonimiasis should be suspected in a Southeast-Asian refugee who presents with a pulmonary lesion which is similar to that of tuberculosis.

Descent Equations Starting from High Rank Chern-Simons

NASA Astrophysics Data System (ADS)

Kang, Bei; Pan, Yi; Wu, Ke; Yang, Jie; Yang, Zi-Feng

2018-04-01

In this paper a set of generalized descent equations are proposed. The solutions to those descent equations labeled by r for any r (r ≥ 2, r ɛ ℕ) are forms of degrees varying from 0 to (2r ‑ 1). And the case of r = 2 is mainly discussed. Supported by National Natural Science Foundation of China under Grant Nos. 11475116, 11401400

Mars Science Laboratory Entry, Descent and Landing System Overview

NASA Technical Reports Server (NTRS)

Steltzner, Adam D.; San Martin, A. Miguel; Rivellini, Tomasso P.; Chen, Allen

2013-01-01

The Mars Science Laboratory project recently places the Curiosity rove on the surface of Mars. With the success of the landing system, the performance envelope of entry, descent and landing capabilities has been extended over the previous state of the art. This paper will present an overview to the MSL entry, descent and landing system design and preliminary flight performance results.

Study of Some Planetary Atmospheres Features by Probe Entry and Descent Simulations

NASA Technical Reports Server (NTRS)

Gil, P. J. S.; Rosa, P. M. B.

2005-01-01

Characterization of planetary atmospheres is analyzed by its effects in the entry and descent trajectories of probes. Emphasis is on the most important variables that characterize atmospheres e.g. density profile with altitude. Probe trajectories are numerically determined with ENTRAP, a developing multi-purpose computational tool for entry and descent trajectory simulations capable of taking into account many features and perturbations. Real data from Mars Pathfinder mission is used. The goal is to be able to determine more accurately the atmosphere structure by observing real trajectories and what changes are to expect in probe descent trajectories if atmospheres have different properties than the ones assumed initially.

Rapid Generation of Optimal Asteroid Powered Descent Trajectories Via Convex Optimization

NASA Technical Reports Server (NTRS)

Pinson, Robin; Lu, Ping

2015-01-01

This paper investigates a convex optimization based method that can rapidly generate the fuel optimal asteroid powered descent trajectory. The ultimate goal is to autonomously design the optimal powered descent trajectory on-board the spacecraft immediately prior to the descent burn. Compared to a planetary powered landing problem, the major difficulty is the complex gravity field near the surface of an asteroid that cannot be approximated by a constant gravity field. This paper uses relaxation techniques and a successive solution process that seeks the solution to the original nonlinear, nonconvex problem through the solutions to a sequence of convex optimal control problems.

NASA aviation safety reporting system

NASA Technical Reports Server (NTRS)

1978-01-01

Reports describing various types of communication problems are presented along with summaries dealing with judgment and decision making. Concerns relating to the ground proximity warning system are summarized and several examples of true terrain proximity warnings are provided. An analytic study of reports relating to profile descents was performed. Problems were found to be associated with charting and graphic presentation of the descents, with lack of uniformity of the descent procedures among facilities using them, and with the flight crew workload engendered by profile descents, particularly when additional requirements are interposed by air traffic control during the execution of the profiles. A selection of alert bulletins and responses to them were reviewed.

Tracer-based Determination of Vortex Descent in the 1999/2000 Arctic Winter

NASA Technical Reports Server (NTRS)

Greenblatt, Jeffrey B.; Jost, Hans-Juerg; Loewenstein, Max; Podolske, James R.; Hurst, Dale F.; Elkins, James W.; Schauffler, Sue M.; Atlas, Elliot L.; Herman, Robert L.; Webster, Chrisotopher R.

2002-01-01

A detailed analysis of available in situ and remotely sensed N2O and CH4 data measured in the 1999/2000 winter Arctic vortex has been performed in order to quantify the temporal evolution of vortex descent. Differences in potential temperature (theta) among balloon and aircraft vertical profiles (an average of 19-23 K on a given N2O or CH4 isopleth) indicated significant vortex inhomogeneity in late fall as compared with late winter profiles. A composite fall vortex profile was constructed for 26 November 1999, whose error bars encompassed the observed variability. High-latitude extravortex profiles measured in different years and seasons revealed substantial variability in N2O and CH4 on theta surfaces, but all were clearly distinguishable from the first vortex profiles measured in late fall 1999. From these extravortex-vortex differences we inferred descent prior to 26 November: as much as 397 plus or minus 15 K (lsigma) at 30 ppbv N2O and 640 ppbv CH4, and falling to 28 plus or minus 13 K above 200 ppbv N2O and 1280 ppbv CH4. Changes in theta were determined on five N2O and CH4 isopleths from 26 November through 12 March, and descent rates were calculated on each N2O isopleth for several time intervals. The maximum descent rates were seen between 26 November and 27 January: 0.82 plus or minus 0.20 K/day averaged over 50- 250 ppbv N2O. By late winter (26 February to 12 March), the average rate had decreased to 0.10 plus or minus 0.25 K/day. Descent rates also decreased with increasing N2O; the winter average (26 November to 5 March) descent rate varied from 0.75 plus or minus 0.10 K/day at 50 ppbv to 0.40 plus or minus 0.11 K/day at 250 ppbv. Comparison of these results with observations and models of descent in prior years showed very good overall agreement. Two models of the 1999/2000 vortex descent, SLIMCAT and REPROBUS, despite theta offsets with respect to observed profiles of up to 20 K on most tracer isopleths, produced descent rates that agreed very favorably with the inferred rates from observation.

Mermaid floating seismometer : A versatile Oceanographic profiler dedicated to the Earthscope Ocean Program.

NASA Astrophysics Data System (ADS)

Hello, Y.; Nolet, G.; Bonnieux, S.; Yegikyan, M.; Chao, Y.; Chen, J.

2016-12-01

Mermaids have been developed to improve seismic data coverage in the oceanic domain for imaging of the Earth's interior. The first generation of Mermaids was housed in conventional Argo-type floats, while hardware and software was developed to analyze acoustic signals, determine whether an earthquake has been recorded, and whether the Mermaid should to come up to the surface and transmit to the satellite. Since 2012, we have deployed small test networks of Mermaids in the Indian Ocean, and in the Mediterranean sea, and we present at this meeting the result from a main network of 9 Mermaids deployed since mid 2014 in the Galapagos archipelago to image the deep plume structure. Since then, we have moved from typical cylinder container, which equips most of the Argo Floats, to a more suitable spherical design, which allows for a larger power supply and more versatile payload. The life time of the new Mermaids is 6 years if sampling continuously for seismic signals, e.g. for seismic tomography by providing worldwide coverage of P wave arrival times. The passband can be widened to allow for monitoring of whale and dolphin sounds. An interface board allows to connect up to 8 external sensors to serve other goals (bio-Argo, geochemical, meteorological). This year we have started collaboration with Sea-Trec to equip the Mermaids with an optional new green renewable power source to guaranty its 6 years lifetime even with a full payload. The Mermaids monitor continuously during the parking phase when drifting freely at a depth down to 3000m, but also provide Argo profiles during the descent. We are collaborating with Sea-Bird to customize an SBE37 to equip the Mermaid for salinity measurements. The new Mermaid has all the features to answer many scientific goals, and a project to develop a user-friendly, adaptable, software system has begun in collaboration with i3s. The first stage of a global network, EarthScope-Oceans, will be launched in 2017, and is planned to grow to 500 units to image the deep interior of the Earth.

Cancer patterns among children of Turkish descent in Germany: A study at the German Childhood Cancer Registry

PubMed Central

Spallek, Jacob; Spix, Claudia; Zeeb, Hajo; Kaatsch, Peter; Razum, Oliver

2008-01-01

Background Cancer risks of migrants might differ from risks of the indigenous population due to differences in socioeconomic status, life style, or genetic factors. The aim of this study was to investigate cancer patterns among children of Turkish descent in Germany. Methods We identified cases with Turkish names (as a proxy of Turkish descent) among the 37,259 cases of childhood cancer registered in the German Childhood Cancer Registry (GCCR) during 1980–2005. As it is not possible to obtain reference population data for children of Turkish descent, the distribution of cancer diagnoses was compared between cases of Turkish descent and all remaining (mainly German) cases in the registry, using proportional cancer incidence ratios (PCIRs). Results The overall distribution of cancer diagnoses was similar in the two groups. The PCIRs in three diagnosis groups were increased for cases of Turkish descent: acute non-lymphocytic leukaemia (PCIR 1.23; CI (95%) 1.02–1.47), Hodgkin's disease (1.34; 1.13–1.59) and Non-Hodgkin/Burkitt lymphoma (1.19; 1.02–1.39). Age, sex, and period of diagnosis showed no influence on the distribution of diagnoses. Conclusion No major differences were found in cancer patterns among cases of Turkish descent compared to all other cases in the GCCR. Slightly higher proportions of systemic malignant diseases indicate that analytical studies involving migrants may help investigating the causes of such cancers. PMID:18462495

The mental health of unaccompanied refugee minors on arrival in the host country.

PubMed

Vervliet, Marianne; Meyer Demott, Melinda A; Jakobsen, Marianne; Broekaert, Eric; Heir, Trond; Derluyn, Ilse

2014-02-01

Despite increasing numbers of unaccompanied refugee minors (UM) in Europe and heightened concerns for this group, research on their mental health has seldom included the factor "time since arrival." As a result, our knowledge of the mental health statuses of UM at specific points in time and over periods in their resettlement trajectories in European host countries is limited. This study therefore examined the mental health of UM shortly after their arrival in Norway (n = 204) and Belgium (n = 103) through the use of self-report questionnaires (HSCL-37A, SLE, RATS, HTQ). High prevalence scores of anxiety, depression and posttraumatic stress disorder (PTSD) symptoms were found. In addition, particular associations were found with the number of traumatic events the UM reported. The results indicate that all UM have high support needs on arrival in the host country. Longitudinal studies following up patterns of continuity and change in their mental health during their trajectories in the host country are necessary. © 2014 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Observation of arrival times of EAS with energies or = 6 x 10 (14) eV

NASA Technical Reports Server (NTRS)

Sun, L.

1985-01-01

The Earth's atmosphere is continually being bombarded by primary cosmic ray particles which are generally believed to be high-energy nuclei. The fact that the majority of cosmic ray primaries are charged particles and that space is permeated with random magnetic fields, means that the particles do not travel in straight lines. The arrival time distribution of EAS may also transfer some information about the primary particles. Actually, if the particles come to our Earth in a completely random process, the arrival time distribution of pairs of successive particles should fit an exponential law. The work reported here was arried out at Sydney University from May 1982 to January 1983. All the data are used to plot the arrival-time distribution of the events, that is, the distribution of time-separation between consecutive events on a 1 minute bin size. During this period more than 2300 showers were recorded. The results are discussed and compared with that of some other experiments.

Steepest descent with momentum for quadratic functions is a version of the conjugate gradient method.

PubMed

Bhaya, Amit; Kaszkurewicz, Eugenius

2004-01-01

It is pointed out that the so called momentum method, much used in the neural network literature as an acceleration of the backpropagation method, is a stationary version of the conjugate gradient method. Connections with the continuous optimization method known as heavy ball with friction are also made. In both cases, adaptive (dynamic) choices of the so called learning rate and momentum parameters are obtained using a control Liapunov function analysis of the system.

CREW Escape Capsule Retrorocket Concept. Volume 2. Selection of a Retrorocket System

DTIC Science & Technology

1977-05-01

Unlimited. 17 DISTRIUTION ST ATEMENT (or h & afiertct entered In Block 20 it different from Repor ) e IS SUPPLEMENTARY NOTES 19 K(EY WOrlDS (Continue -r...c.& UNCLASSIFIED SECUR TN CLASSIFICATION OF THIS PAGE(Wrin Veta Entered) 20. combination with recovery system descent rates of 30 through 60 ft/sec...thrusts are calculated by equation 1. A value of ignition height error E = ±0.5 ft or 2 JEL = 1.0 ft was selected as a design goal based on previous

The Role of la Familia for Women of Mexican Descent Who Are Leaders in Higher Education

ERIC Educational Resources Information Center

Elizondo, Sandra Gray

2012-01-01

The purpose of this qualitative case study was to describe the role of "la familia" for women of Mexican descent as it relates to their development as leaders and their leadership in academia. Purposeful sampling was utilized to reach the goal of 18 participants who were female academic leaders of Mexican descent teaching full time in…

Forecasting international tourism demand from the US, Japan and South Korea to Malaysia: A SARIMA approach

NASA Astrophysics Data System (ADS)

Borhan, Nurbaizura; Arsad, Zainudin

2014-07-01

One of the major contributing sectors for Malaysia's economic growth is tourism. The number of international tourist arrivals to Malaysia has been showing an upward trend as a result of several programs and promotion introduced by the Malaysian government to attract international tourists to the country. This study attempts to model and to forecast tourism demand for Malaysia by three selected countries: the US, Japan and South Korea. This study utilized monthly time series data for the period from January 1999 to December 2012 and employed the well-known Box-Jenkins seasonal ARIMA modeling procedures. Not surprisingly the results show the number of tourist arrivals from the three countries contain strong seasonal component as the arrivals strongly dependent on the season in the country of origin. The findings of the study also show that the number of tourist arrivals from the US and South Korea will continue to increase in the near future. Meanwhile the arrivals from Japan is forecasted to show a drop in the near future and as such tourism authorities in Malaysia need to enhance the promotional effort to attract more tourists from Japan to visit Malaysia.

The Genetics of Bene Israel from India Reveals Both Substantial Jewish and Indian Ancestry

PubMed Central

Davidson, Natalie R.; Billing-Ross, Paul; Dubrovsky, Maya; Campbell, Christopher L.; Oddoux, Carole; Friedman, Eitan; Atzmon, Gil; Halperin, Eran; Ostrer, Harry; Keinan, Alon

2016-01-01

The Bene Israel Jewish community from West India is a unique population whose history before the 18th century remains largely unknown. Bene Israel members consider themselves as descendants of Jews, yet the identity of Jewish ancestors and their arrival time to India are unknown, with speculations on arrival time varying between the 8th century BCE and the 6th century CE. Here, we characterize the genetic history of Bene Israel by collecting and genotyping 18 Bene Israel individuals. Combining with 486 individuals from 41 other Jewish, Indian and Pakistani populations, and additional individuals from worldwide populations, we conducted comprehensive genome-wide analyses based on FST, principal component analysis, ADMIXTURE, identity-by-descent sharing, admixture linkage disequilibrium decay, haplotype sharing and allele sharing autocorrelation decay, as well as contrasted patterns between the X chromosome and the autosomes. The genetics of Bene Israel individuals resemble local Indian populations, while at the same time constituting a clearly separated and unique population in India. They are unique among Indian and Pakistani populations we analyzed in sharing considerable genetic ancestry with other Jewish populations. Putting together the results from all analyses point to Bene Israel being an admixed population with both Jewish and Indian ancestry, with the genetic contribution of each of these ancestral populations being substantial. The admixture took place in the last millennium, about 19–33 generations ago. It involved Middle-Eastern Jews and was sex-biased, with more male Jewish and local female contribution. It was followed by a population bottleneck and high endogamy, which can lead to increased prevalence of recessive diseases in this population. This study provides an example of how genetic analysis advances our knowledge of human history in cases where other disciplines lack the relevant data to do so. PMID:27010569

The Genetics of Bene Israel from India Reveals Both Substantial Jewish and Indian Ancestry.

PubMed

Waldman, Yedael Y; Biddanda, Arjun; Davidson, Natalie R; Billing-Ross, Paul; Dubrovsky, Maya; Campbell, Christopher L; Oddoux, Carole; Friedman, Eitan; Atzmon, Gil; Halperin, Eran; Ostrer, Harry; Keinan, Alon

2016-01-01

The Bene Israel Jewish community from West India is a unique population whose history before the 18th century remains largely unknown. Bene Israel members consider themselves as descendants of Jews, yet the identity of Jewish ancestors and their arrival time to India are unknown, with speculations on arrival time varying between the 8th century BCE and the 6th century CE. Here, we characterize the genetic history of Bene Israel by collecting and genotyping 18 Bene Israel individuals. Combining with 486 individuals from 41 other Jewish, Indian and Pakistani populations, and additional individuals from worldwide populations, we conducted comprehensive genome-wide analyses based on FST, principal component analysis, ADMIXTURE, identity-by-descent sharing, admixture linkage disequilibrium decay, haplotype sharing and allele sharing autocorrelation decay, as well as contrasted patterns between the X chromosome and the autosomes. The genetics of Bene Israel individuals resemble local Indian populations, while at the same time constituting a clearly separated and unique population in India. They are unique among Indian and Pakistani populations we analyzed in sharing considerable genetic ancestry with other Jewish populations. Putting together the results from all analyses point to Bene Israel being an admixed population with both Jewish and Indian ancestry, with the genetic contribution of each of these ancestral populations being substantial. The admixture took place in the last millennium, about 19-33 generations ago. It involved Middle-Eastern Jews and was sex-biased, with more male Jewish and local female contribution. It was followed by a population bottleneck and high endogamy, which can lead to increased prevalence of recessive diseases in this population. This study provides an example of how genetic analysis advances our knowledge of human history in cases where other disciplines lack the relevant data to do so.

Foundational Methane Propulsion Related Technology Efforts, and Challenges for Applications to Human Exploration Beyond Earth Orbit

NASA Technical Reports Server (NTRS)

Brown, Thomas; Klem, Mark; McRight, Patrick

2016-01-01

Current interest in human exploration beyond earth orbit is driving requirements for high performance, long duration space transportation capabilities. Continued advancement in photovoltaic power systems and investments in high performance electric propulsion promise to enable solar electric options for cargo delivery and pre-deployment of operational architecture elements. However, higher thrust options are required for human in-space transportation as well as planetary descent and ascent functions. While high thrust requirements for interplanetary transportation may be provided by chemical or nuclear thermal propulsion systems, planetary descent and ascent systems are limited to chemical solutions due to their higher thrust to weight and potential planetary protection concerns. Liquid hydrogen fueled systems provide high specific impulse, but pose challenges due to low propellant density and the thermal issues of long term propellant storage. Liquid methane fueled propulsion is a promising compromise with lower specific impulse, higher bulk propellant density and compatibility with proposed in-situ propellant production concepts. Additionally, some architecture studies have identified the potential for commonality between interplanetary and descent/ascent propulsion solutions using liquid methane (LCH4) and liquid oxygen (LOX) propellants. These commonalities may lead to reduced overall development costs and more affordable exploration architectures. With this increased interest, it is critical to understand the current state of LOX/LCH4 propulsion technology and the remaining challenges to its application to beyond earth orbit human exploration. This paper provides a survey of NASA's past and current methane propulsion related technology efforts, assesses the accomplishments to date, and examines the remaining risks associated with full scale development.

The VSPA Foot: A Quasi-Passive Ankle-Foot Prosthesis With Continuously Variable Stiffness.

PubMed

Shepherd, Max K; Rouse, Elliott J

2017-12-01

Most commercially available prosthetic feet do not exhibit a biomimetic torque-angle relationship, and are unable to modulate their mechanics to assist with other mobility tasks, such as stairs and ramps. In this paper, we present a quasi-passive ankle-foot prosthesis with a customizable torque-angle curve and an ability to quickly modulate ankle stiffness between tasks. The customizable torque-angle curve is obtained with a cam-based transmission and a fiberglass leaf spring. To achieve variable stiffness, the leaf spring's support conditions can be actively modulated by a small motor, shifting the torque-angle curve to be more or less stiff. We introduce the design, characterize the available torque-angle curves, and present kinematics from a transtibial amputee subject performing level-ground walking, stair ascent/descent, and ramp ascent/descent. The subject exhibited a more normative range of motion on stairs and ramps at lower stiffness levels, and preferred different stiffness levels for each task. Paired with an appropriate intent recognition system, our novel ankle prosthesis could improve gait biomechanics during walking and many other mobility tasks.

Evaluating the accuracy performance of Lucas-Kanade algorithm in the circumstance of PIV application

NASA Astrophysics Data System (ADS)

Pan, Chong; Xue, Dong; Xu, Yang; Wang, JinJun; Wei, RunJie

2015-10-01

Lucas-Kanade (LK) algorithm, usually used in optical flow filed, has recently received increasing attention from PIV community due to its advanced calculation efficiency by GPU acceleration. Although applications of this algorithm are continuously emerging, a systematic performance evaluation is still lacking. This forms the primary aim of the present work. Three warping schemes in the family of LK algorithm: forward/inverse/symmetric warping, are evaluated in a prototype flow of a hierarchy of multiple two-dimensional vortices. Second-order Newton descent is also considered here. The accuracy & efficiency of all these LK variants are investigated under a large domain of various influential parameters. It is found that the constant displacement constraint, which is a necessary building block for GPU acceleration, is the most critical issue in affecting LK algorithm's accuracy, which can be somehow ameliorated by using second-order Newton descent. Moreover, symmetric warping outbids the other two warping schemes in accuracy level, robustness to noise, convergence speed and tolerance to displacement gradient, and might be the first choice when applying LK algorithm to PIV measurement.

Understanding and Optimizing Asynchronous Low-Precision Stochastic Gradient Descent

PubMed Central

De Sa, Christopher; Feldman, Matthew; Ré, Christopher; Olukotun, Kunle

2018-01-01

Stochastic gradient descent (SGD) is one of the most popular numerical algorithms used in machine learning and other domains. Since this is likely to continue for the foreseeable future, it is important to study techniques that can make it run fast on parallel hardware. In this paper, we provide the first analysis of a technique called Buckwild! that uses both asynchronous execution and low-precision computation. We introduce the DMGC model, the first conceptualization of the parameter space that exists when implementing low-precision SGD, and show that it provides a way to both classify these algorithms and model their performance. We leverage this insight to propose and analyze techniques to improve the speed of low-precision SGD. First, we propose software optimizations that can increase throughput on existing CPUs by up to 11×. Second, we propose architectural changes, including a new cache technique we call an obstinate cache, that increase throughput beyond the limits of current-generation hardware. We also implement and analyze low-precision SGD on the FPGA, which is a promising alternative to the CPU for future SGD systems. PMID:29391770

Energy minimization in medical image analysis: Methodologies and applications.

PubMed

Zhao, Feng; Xie, Xianghua

2016-02-01

Energy minimization is of particular interest in medical image analysis. In the past two decades, a variety of optimization schemes have been developed. In this paper, we present a comprehensive survey of the state-of-the-art optimization approaches. These algorithms are mainly classified into two categories: continuous method and discrete method. The former includes Newton-Raphson method, gradient descent method, conjugate gradient method, proximal gradient method, coordinate descent method, and genetic algorithm-based method, while the latter covers graph cuts method, belief propagation method, tree-reweighted message passing method, linear programming method, maximum margin learning method, simulated annealing method, and iterated conditional modes method. We also discuss the minimal surface method, primal-dual method, and the multi-objective optimization method. In addition, we review several comparative studies that evaluate the performance of different minimization techniques in terms of accuracy, efficiency, or complexity. These optimization techniques are widely used in many medical applications, for example, image segmentation, registration, reconstruction, motion tracking, and compressed sensing. We thus give an overview on those applications as well. Copyright © 2015 John Wiley & Sons, Ltd.

Mars Sample Return Using Commercial Capabilities: Propulsive Entry, Descent, and Landing of a Capsule Form Vehicle

NASA Technical Reports Server (NTRS)

Gonzales, Andrew A.; Lemke, Lawrence G.; Huynh, Loc C.

2014-01-01

This paper describes a critical portion of the work that has been done at NASA, Ames Research Center regarding the use of the commercially developed Dragon capsule as a delivery vehicle for the elements of a high priority Mars Sample Return mission. The objective of the investigation was to determine entry and landed mass capabilities that cover anticipated mission conditions. The "Red Dragon", Mars configuration, uses supersonic retro-propulsion, with no required parachute system, to perform Entry, Descent, and Landing (EDL) maneuvers. The propulsive system proposed for use is the same system that will perform an abort, if necessary, for a human rated version of the Dragon capsule. Standard trajectory analysis tools are applied to publically available information about Dragon and other legacy capsule forms in order to perform the investigation. Trajectory simulation parameters include entry velocity, flight path angle, lift to drag Ratio (L/D), landing site elevation, atmosphere density, and total entry mass, in addition engineering assumptions for the performance of the propulsion system are stated. Mass estimates for major elements of the overall proposed architecture are coupled to this EDL analysis to close the overall architecture. Three synodic launch opportunities, beginning with the 2022 opportunity, define the arrival conditions. Results state the relations between the analysis parameters as well as sensitivities to those parameters. The EDL performance envelope includes landing altitudes between 0 and -4 km referenced to the Mars Orbiter Laser Altimeter datum as well as minimum and maximum atmosphere density. Total entry masses between 7 and 10 mt are considered with architecture closure occurring between 9.0 and 10 mt. Propellant mass fractions for each major phase of the EDL - Entry, Terminal Descent, and Hazard Avoidance - have been derived. An assessment of the effect of the entry conditions on the Thermal Protection System (TPS) currently in use for Dragon missions shows no significant stressors. A useful payload mass of 2.0 mt is provided and includes mass and grow allowance for a Mars Ascent Vehicle (MAV), Earth Return Vehicle (ERV), and mission unique equipment. The useful payload supports an architecture that receives a sample from another surface asset and sends it directly back to Earth for recovery in a high Earth orbit. The work shows that emerging commercial capabilities as well as previously studied EDL methodologies can be used to efficiently support an important planetary science objective. The work also has applications for human exploration missions that will also use propulsive EDL techniques

Surface erosion caused on Mars from Viking descent engine plume

USGS Publications Warehouse

Hutton, R.E.; Moore, H.J.; Scott, R.F.; Shorthill, R.W.; Spitzer, C.R.

1980-01-01

During the Martian landings the descent engine plumes on Viking Lander 1 (VL-1) and Viking Lander 2 (VL-2) eroded the Martian surface materials. This had been anticipated and investigated both analytically and experimentally during the design phase of the Viking spacecraft. This paper presents data on erosion obtained during the tests of the Viking descent engine and the evidence for erosion by the descent engines of VL-1 and VL-2 on Mars. From these and other results, it is concluded that there are four distinct surface materials on Mars: (1) drift material, (2) crusty to cloddy material, (3) blocky material, and (4) rock. ?? 1980 D. Reidel Publishing Co.

Local flow management/profile descent algorithm. Fuel-efficient, time-controlled profiles for the NASA TSRV airplane

NASA Technical Reports Server (NTRS)

Groce, J. L.; Izumi, K. H.; Markham, C. H.; Schwab, R. W.; Thompson, J. L.

1986-01-01

The Local Flow Management/Profile Descent (LFM/PD) algorithm designed for the NASA Transport System Research Vehicle program is described. The algorithm provides fuel-efficient altitude and airspeed profiles consistent with ATC restrictions in a time-based metering environment over a fixed ground track. The model design constraints include accommodation of both published profile descent procedures and unpublished profile descents, incorporation of fuel efficiency as a flight profile criterion, operation within the performance capabilities of the Boeing 737-100 airplane with JT8D-7 engines, and conformity to standard air traffic navigation and control procedures. Holding and path stretching capabilities are included for long delay situations.

State dependent arrival in bulk retrial queueing system with immediate Bernoulli feedback, multiple vacations and threshold

NASA Astrophysics Data System (ADS)

Niranjan, S. P.; Chandrasekaran, V. M.; Indhira, K.

2017-11-01

The objective of this paper is to analyse state dependent arrival in bulk retrial queueing system with immediate Bernoulli feedback, multiple vacations, threshold and constant retrial policy. Primary customers are arriving into the system in bulk with different arrival rates λ a and λ b . If arriving customers find the server is busy then the entire batch will join to orbit. Customer from orbit request service one by one with constant retrial rate γ. On the other hand if an arrival of customers finds the server is idle then customers will be served in batches according to general bulk service rule. After service completion, customers may request service again with probability δ as feedback or leave from the system with probability 1 - δ. In the service completion epoch, if the orbit size is zero then the server leaves for multiple vacations. The server continues the vacation until the orbit size reaches the value ‘N’ (N > b). At the vacation completion, if the orbit size is ‘N’ then the server becomes ready to provide service for customers from the main pool or from the orbit. For the designed queueing model, probability generating function of the queue size at an arbitrary time will be obtained by using supplementary variable technique. Various performance measures will be derived with suitable numerical illustrations.

Integrated Targeting and Guidance for Powered Planetary Descent

NASA Astrophysics Data System (ADS)

Azimov, Dilmurat M.; Bishop, Robert H.

2018-02-01

This paper presents an on-board guidance and targeting design that enables explicit state and thrust vector control and on-board targeting for planetary descent and landing. These capabilities are developed utilizing a new closed-form solution for the constant thrust arc of the braking phase of the powered descent trajectory. The key elements of proven targeting and guidance architectures, including braking and approach phase quartics, are employed. It is demonstrated that implementation of the proposed solution avoids numerical simulation iterations, thereby facilitating on-board execution of targeting procedures during the descent. It is shown that the shape of the braking phase constant thrust arc is highly dependent on initial mass and propulsion system parameters. The analytic solution process is explicit in terms of targeting and guidance parameters, while remaining generic with respect to planetary body and descent trajectory design. These features increase the feasibility of extending the proposed integrated targeting and guidance design to future cargo and robotic landing missions.

Integrated Targeting and Guidance for Powered Planetary Descent

NASA Astrophysics Data System (ADS)

Azimov, Dilmurat M.; Bishop, Robert H.

2018-06-01

This paper presents an on-board guidance and targeting design that enables explicit state and thrust vector control and on-board targeting for planetary descent and landing. These capabilities are developed utilizing a new closed-form solution for the constant thrust arc of the braking phase of the powered descent trajectory. The key elements of proven targeting and guidance architectures, including braking and approach phase quartics, are employed. It is demonstrated that implementation of the proposed solution avoids numerical simulation iterations, thereby facilitating on-board execution of targeting procedures during the descent. It is shown that the shape of the braking phase constant thrust arc is highly dependent on initial mass and propulsion system parameters. The analytic solution process is explicit in terms of targeting and guidance parameters, while remaining generic with respect to planetary body and descent trajectory design. These features increase the feasibility of extending the proposed integrated targeting and guidance design to future cargo and robotic landing missions.

A molecular signature of an arrest of descent in human parturition

PubMed Central

MITTAL, Pooja; ROMERO, Roberto; TARCA, Adi L.; DRAGHICI, Sorin; NHAN-CHANG, Chia-Ling; CHAIWORAPONGSA, Tinnakorn; HOTRA, John; GOMEZ, Ricardo; KUSANOVIC, Juan Pedro; LEE, Deug-Chan; KIM, Chong Jai; HASSAN, Sonia S.

2010-01-01

Objective This study was undertaken to identify the molecular basis of an arrest of descent. Study Design Human myometrium was obtained from women in term labor (TL; n=29) and arrest of descent (AODes, n=21). Gene expression was characterized using Illumina® HumanHT-12 microarrays. A moderated t-test and false discovery rate adjustment were applied for analysis. Confirmatory qRT-PCR and immunoblot was performed in an independent sample set. Results 400 genes were differentially expressed between women with an AODes compared to those with TL. Gene Ontology analysis indicated enrichment of biological processes and molecular functions related to inflammation and muscle function. Impacted pathways included inflammation and the actin cytoskeleton. Overexpression of HIF1A, IL-6, and PTGS2 in AODES was confirmed. Conclusion We have identified a stereotypic pattern of gene expression in the myometrium of women with an arrest of descent. This represents the first study examining the molecular basis of an arrest of descent using a genome-wide approach. PMID:21284969

Design principles of descent vehicles with an inflatable braking device

NASA Astrophysics Data System (ADS)

Alexashkin, S. N.; Pichkhadze, K. M.; Finchenko, V. S.

2013-12-01

A new type of descent vehicle (DVs) is described: a descent vehicle with an inflatable braking device (IBD DV). IBD development issues, as well as materials needed for the design, manufacturing, and testing of an IBD and its thermal protection, are discussed. A list is given of Russian integrated test facilities intended for testing IBD DVs. Progress is described in the development of IBD DVs in Russia and abroad.

Synonymous ABCA3 Variants Do Not Increase Risk for Neonatal Respiratory Distress Syndrome

PubMed Central

Wambach, Jennifer A.; Wegner, Daniel J.; Heins, Hillary B.; Druley, Todd E.; Mitra, Robi D.; Hamvas, Aaron; Cole, F. Sessions

2014-01-01

Objective To determine whether synonymous variants in the adenosine triphosphate-binding cassette A3 transporter (ABCA3) gene increase the risk for neonatal respiratory distress syndrome (RDS) in term and late preterm infants of European and African descent. Study design Using next-generation pooled sequencing of race-stratified DNA samples from infants of European and African descent at $34 weeks gestation with and without RDS (n = 503), we scanned all exons of ABCA3, validated each synonymous variant with an independent genotyping platform, and evaluated race-stratified disease risk associated with common synonymous variants and collapsed frequencies of rare synonymous variants. Results The synonymous ABCA3 variant frequency spectrum differs between infants of European descent and those of African descent. Using in silico prediction programs and statistical strategies, we found no potentially disruptive synonymous ABCA3 variants or evidence of selection pressure. Individual common synonymous variants and collapsed frequencies of rare synonymous variants did not increase disease risk in term and late-preterm infants of European or African descent. Conclusion In contrast to rare, nonsynonymous ABCA3 mutations, synonymous ABCA3 variants do not increase the risk for neonatal RDS among term and late-preterm infants of European or African descent. PMID:24657120

A systematic review and meta-analysis of comparative studies assessing the efficacy of luteinizing hormone-releasing hormone therapy for children with cryptorchidism.

PubMed

Li, Tao; Gao, Liang; Chen, Peng; Bu, Siyuan; Cao, Dehong; Yang, Lu; Wei, Qiang

2016-05-01

To assess the efficacy of intranasal luteinizing hormone-releasing hormone (LHRH) therapy for cryptorchidism. Eligible studies were identified by two reviewers using PubMed, Embase, and Web of Science databases. Primary outcomes were complete testicular descent rate, complete testicular descent rate for nonpalpable testis, and pre-scrotal and inguinal testis. Secondary outcomes included testicular descent with different medicines strategy and a subgroup analysis. Pooled data including the 1255 undescended testes showed that complete testicular descent rate was 20.9 % in LHRH group versus 5.6 % in the placebo group, which was significantly different [relative risk (RR) 3.94, 95 % confidence interval (CI) 2.14-7.28, P < 0.0001]. There was also a significant difference in the incidence of pre-scrotal and inguinal position testis descent, with 22.8 % in the LHRH group versus 3.6 % in the placebo group (RR 5.79, 95 % CI 2.94-11.39, P < 0.00001). However, side effects were more frequent in the LHRH group (RR 2.61, 95 % CI 1.52-4.49, P = 0.0005). There were no significant differences for nonpalpable testes. LHRH had significant benefits on testicular descent, particularly for inguinal and pre-scrotal testes, which was also accompanied by temporary slight side effects.

Global Patterns of Prostate Cancer Incidence, Aggressiveness, and Mortality in Men of African Descent

PubMed Central

Rebbeck, Timothy R.; Devesa, Susan S.; Chang, Bao-Li; Bunker, Clareann H.; Cheng, Iona; Cooney, Kathleen; Eeles, Rosalind; Fernandez, Pedro; Giri, Veda N.; Gueye, Serigne M.; Haiman, Christopher A.; Henderson, Brian E.; Heyns, Chris F.; Hu, Jennifer J.; Ingles, Sue Ann; Isaacs, William; Jalloh, Mohamed; John, Esther M.; Kibel, Adam S.; Kidd, LaCreis R.; Layne, Penelope; Leach, Robin J.; Neslund-Dudas, Christine; Okobia, Michael N.; Ostrander, Elaine A.; Park, Jong Y.; Patrick, Alan L.; Phelan, Catherine M.; Ragin, Camille; Roberts, Robin A.; Rybicki, Benjamin A.; Stanford, Janet L.; Strom, Sara; Thompson, Ian M.; Witte, John; Xu, Jianfeng; Yeboah, Edward; Hsing, Ann W.; Zeigler-Johnson, Charnita M.

2013-01-01

Prostate cancer (CaP) is the leading cancer among men of African descent in the USA, Caribbean, and Sub-Saharan Africa (SSA). The estimated number of CaP deaths in SSA during 2008 was more than five times that among African Americans and is expected to double in Africa by 2030. We summarize publicly available CaP data and collected data from the men of African descent and Carcinoma of the Prostate (MADCaP) Consortium and the African Caribbean Cancer Consortium (AC3) to evaluate CaP incidence and mortality in men of African descent worldwide. CaP incidence and mortality are highest in men of African descent in the USA and the Caribbean. Tumor stage and grade were highest in SSA. We report a higher proportion of T1 stage prostate tumors in countries with greater percent gross domestic product spent on health care and physicians per 100,000 persons. We also observed that regions with a higher proportion of advanced tumors reported lower mortality rates. This finding suggests that CaP is underdiagnosed and/or underreported in SSA men. Nonetheless, CaP incidence and mortality represent a significant public health problem in men of African descent around the world. PMID:23476788

The GalileoJupiter Probe Doppler Wind Experiment

NASA Astrophysics Data System (ADS)

Atkinson, D. H.

2001-09-01

The GalileoJupiter atmospheric entry probe was launched along with the Galileoorbiter spacecraft from Cape Canaveral in Florida, USA, on October 18, 1989. Following a cruise of greater than six years, the probe arrived at Jupiter on December 7, 1995. During its 57-minute descent, instruments on the probe studied the atmospheric composition and structure, the clouds, lightning, and energy structure of the upper Jovian atmosphere. One of the two radio channels over which the experiment data was transmitted to the orbiter was driven by an ultrastable oscillator. All motions of the probe and orbiter, including the speed of probe descent, Jupiter's rotation, and the atmospheric winds, contributed to a Doppler shift of the probe radio frequency. By accurately measuring the frequency of the probe radio signal, an accurate time history of the probe-orbiter relative motions could be reconstructed. Knowledge of the nominal probe and orbiter trajectories allowed the nominal Doppler shift to be removed from the probe radio frequency leaving a measurable frequency residual arising primarily from the zonal winds in Jupiter's atmosphere, and micromotions of the probe arising from probe spin, swing under the parachute, atmospheric turbulence, and aerodynamic effects. Assuming that the zonal horizontal winds dominate the residual probe motion, a profile of frequency residuals was generated. Inversion of the frequency residuals resulted in the first in situ measurements of the vertical profile of Jupiter's deep zonal winds. It is found that beneath 700 mb, the winds are strong and prograde, rising rapidly to 170 m/s between 1 and 4 bars. Beneath 4 bars to 21 bars, the depth at which the link with the probe was lost, the winds remain constant and strong. When corrections for the high temperatures encountered by the probe are considered, there is no evidence of diminishing or strengthening of the zonal winds in the deepest regions explored by the Galileoprobe. Following the wind recovery, the frequency residuals offer tantalizing clues to microstructure in the atmospheric dynamics, including turbulence and wave motion.

Evolutionary analyses of non-genealogical bonds produced by introgressive descent.

PubMed

Bapteste, Eric; Lopez, Philippe; Bouchard, Frédéric; Baquero, Fernando; McInerney, James O; Burian, Richard M

2012-11-06

All evolutionary biologists are familiar with evolutionary units that evolve by vertical descent in a tree-like fashion in single lineages. However, many other kinds of processes contribute to evolutionary diversity. In vertical descent, the genetic material of a particular evolutionary unit is propagated by replication inside its own lineage. In what we call introgressive descent, the genetic material of a particular evolutionary unit propagates into different host structures and is replicated within these host structures. Thus, introgressive descent generates a variety of evolutionary units and leaves recognizable patterns in resemblance networks. We characterize six kinds of evolutionary units, of which five involve mosaic lineages generated by introgressive descent. To facilitate detection of these units in resemblance networks, we introduce terminology based on two notions, P3s (subgraphs of three nodes: A, B, and C) and mosaic P3s, and suggest an apparatus for systematic detection of introgressive descent. Mosaic P3s correspond to a distinct type of evolutionary bond that is orthogonal to the bonds of kinship and genealogy usually examined by evolutionary biologists. We argue that recognition of these evolutionary bonds stimulates radical rethinking of key questions in evolutionary biology (e.g., the relations among evolutionary players in very early phases of evolutionary history, the origin and emergence of novelties, and the production of new lineages). This line of research will expand the study of biological complexity beyond the usual genealogical bonds, revealing additional sources of biodiversity. It provides an important step to a more realistic pluralist treatment of evolutionary complexity.

Mars Descent Imager (MARDI) on the Mars Polar Lander

USGS Publications Warehouse

Malin, M.C.; Caplinger, M.A.; Carr, M.H.; Squyres, S.; Thomas, P.; Veverka, J.

2001-01-01

The Mars Descent Imager, or MARDI, experiment on the Mars Polar Lander (MPL) consists of a camera characterized by small physical size and mass (???6 ?? 6 ?? 12 cm, including baffle; <500 gm), low power requirements (<2.5 W, including power supply losses), and high science performance (1000 x 1000 pixel, low noise). The intent of the investigation is to acquire nested images over a range of resolutions, from 8 m/pixel to better than 1 cm/pixel, during the roughly 2 min it takes the MPL to descend from 8 km to the surface under parachute and rocket-powered deceleration. Observational goals will include studies of (1) surface morphology (e.g., nature and distribution of landforms indicating past and present environmental processes); (2) local and regional geography (e.g., context for other lander instruments: precise location, detailed local relief); and (3) relationships to features seen in orbiter data. To accomplish these goals, MARDI will collect three types of images. Four small images (256 x 256 pixels) will be acquired on 0.5 s centers beginning 0.3 s before MPL's heatshield is jettisoned. Sixteen full-frame images (1024 X 1024, circularly edited) will be acquired on 5.3 s centers thereafter. Just after backshell jettison but prior to the start of powered descent, a "best final nonpowered descent image" will be acquired. Five seconds after the start of powered descent, the camera will begin acquiring images on 4 s centers. Storage for as many as ten 800 x 800 pixel images is available during terminal descent. A number of spacecraft factors are likely to impact the quality of MARDI images, including substantial motion blur resulting from large rates of attitude variation during parachute descent and substantial rocket-engine-induced vibration during powered descent. In addition, the mounting location of the camera places the exhaust plume of the hydrazine engines prominently in the field of view. Copyright 2001 by the American Geophysical Union.

A comprehensive review of prehospital and in-hospital delay times in acute stroke care.

PubMed

Evenson, K R; Foraker, R E; Morris, D L; Rosamond, W D

2009-06-01

The purpose of this study was to systematically review and summarize prehospital and in-hospital stroke evaluation and treatment delay times. We identified 123 unique peer-reviewed studies published from 1981 to 2007 of prehospital and in-hospital delay time for evaluation and treatment of patients with stroke, transient ischemic attack, or stroke-like symptoms. Based on studies of 65 different population groups, the weighted Poisson regression indicated a 6.0% annual decline (P<0.001) in hours/year for prehospital delay, defined from symptom onset to emergency department arrival. For in-hospital delay, the weighted Poisson regression models indicated no meaningful changes in delay time from emergency department arrival to emergency department evaluation (3.1%, P=0.49 based on 12 population groups). There was a 10.2% annual decline in hours/year from emergency department arrival to neurology evaluation or notification (P=0.23 based on 16 population groups) and a 10.7% annual decline in hours/year for delay time from emergency department arrival to initiation of computed tomography (P=0.11 based on 23 population groups). Only one study reported on times from arrival to computed tomography scan interpretation, two studies on arrival to drug administration, and no studies on arrival to transfer to an in-patient setting, precluding generalizations. Prehospital delay continues to contribute the largest proportion of delay time. The next decade provides opportunities to establish more effective community-based interventions worldwide. It will be crucial to have effective stroke surveillance systems in place to better understand and improve both prehospital and in-hospital delays for acute stroke care.

Refugees, Veterans, and Continuing Pedagogies of PTSD in Asian American Studies

ERIC Educational Resources Information Center

Tang, Shirley Suet-ling; Kiang, Peter Nien-chu

2011-01-01

In this chapter, the authors describe how a pedagogical commitment at one urban public school to support teaching and learning with Southeast Asian refugee students and their Vietnam veteran classmates two decades ago has continued to be meaningful for more recently arrived refugee students from other world regions, as well as for a diverse, new…

A Study of the Delivery of Adult Walk-In Primary Care at Womack Army Hospital, Fort Bragg, North Carolina

DTIC Science & Technology

1980-05-01

patients have begun arriving, they start out behind and they continue to get further behind as the morning progresses. This factor was brought to the...program and give a false indication of the actual time that paients had to spend in the AMOSIST program to get definitive care. It can be seen in...AMOSISTs in the AMIC. In the mornings, when the arrival rate and the patient load are the heaviest, there was a tendency for the physician to get somewhat

Method for utilizing decay heat from radioactive nuclear wastes

DOEpatents

Busey, H.M.

1974-10-14

Management of radioactive heat-producing waste material while safely utilizing the heat thereof is accomplished by encapsulating the wastes after a cooling period, transporting the capsules to a facility including a plurality of vertically disposed storage tubes, lowering the capsules as they arrive at the facility into the storage tubes, cooling the storage tubes by circulating a gas thereover, employing the so heated gas to obtain an economically beneficial result, and continually adding waste capsules to the facility as they arrive thereat over a substantial period of time.

Advances in POST2 End-to-End Descent and Landing Simulation for the ALHAT Project

NASA Technical Reports Server (NTRS)

Davis, Jody L.; Striepe, Scott A.; Maddock, Robert W.; Hines, Glenn D.; Paschall, Stephen, II; Cohanim, Babak E.; Fill, Thomas; Johnson, Michael C.; Bishop, Robert H.; DeMars, Kyle J.;

Fast Optimization for Aircraft Descent and Approach Trajectory

NASA Technical Reports Server (NTRS)

Luchinsky, Dmitry G.; Schuet, Stefan; Brenton, J.; Timucin, Dogan; Smith, David; Kaneshige, John

2017-01-01

We address problem of on-line scheduling of the aircraft descent and approach trajectory. We formulate a general multiphase optimal control problem for optimization of the descent trajectory and review available methods of its solution. We develop a fast algorithm for solution of this problem using two key components: (i) fast inference of the dynamical and control variables of the descending trajectory from the low dimensional flight profile data and (ii) efficient local search for the resulting reduced dimensionality non-linear optimization problem. We compare the performance of the proposed algorithm with numerical solution obtained using optimal control toolbox General Pseudospectral Optimal Control Software. We present results of the solution of the scheduling problem for aircraft descent using novel fast algorithm and discuss its future applications.

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

[The royal philanthropic expedition of the vaccine (Xavier de Balmis/Josep Salvany). 1803-1806].

PubMed

Botet, Francesc Asensi

2009-12-01

Six years after Jenner discovered the anti-smallpox vaccine, King Charles IV mandated the initiation of vaccination campaigns throughout his kingdom. The overseas campaign was coordinated by the Valencian military doctor Xavier de Balmis with the aid of the Catalan Josep Salvany. The vaccine was transported to America "in vivo" in 22 children. The expedition departed from La Coruña on November 1806 and arrived to the Venezuelan port of La Guayra where it was split in two: One sub expedition under the order of Josep Salvany, continued by land to Colombia, Ecuador, Peru and Bolivia. Salvany died in the Bolivian city of Cochabamba. The other sub expedition, leaded by Balmis himself, continued by sea to Cuba and Mexico. From Acapulco it arrived to Manila and from there to Macau followed by inland penetration into China.

The Hölder continuity of spectral measures of an extended CMV matrix

NASA Astrophysics Data System (ADS)

Munger, Paul E.; Ong, Darren C.

2014-09-01

We prove results about the Hölder continuity of the spectral measures of the extended CMV matrix, given power law bounds of the solution of the eigenvalue equation. We thus arrive at a unitary analogue of the results of Damanik, Killip, and Lenz ["Uniform spectral properties of one-dimensional quasicrystals, III. α-continuity," Commun. Math. Phys. 212, 191-204 (2000)] about the spectral measure of the discrete Schrödinger operator.

The Hölder continuity of spectral measures of an extended CMV matrix.

PubMed

Munger, Paul E; Ong, Darren C

2014-09-01

We prove results about the Hölder continuity of the spectral measures of the extended CMV matrix, given power law bounds of the solution of the eigenvalue equation. We thus arrive at a unitary analogue of the results of Damanik, Killip, and Lenz ["Uniform spectral properties of one-dimensional quasicrystals, III. α-continuity," Commun. Math. Phys.55, 191-204 (2000)] about the spectral measure of the discrete Schrödinger operator.

Is prenatal urethral descent a risk factor for urinary incontinence during pregnancy and the postpartum period?

PubMed

Pizzoferrato, Anne-Cécile; Fauconnier, Arnaud; Bader, Georges; de Tayrac, Renaud; Fort, Julie; Fritel, Xavier

2016-07-01

Obstetric trauma during childbirth is considered a major risk factor for postpartum urinary incontinence (UI), particularly stress urinary incontinence. Our aim was to investigate the relation between postpartum UI, mode of delivery, and urethral descent, and to define a group of women who are particularly at risk of postnatal UI. A total of 186 women were included their first pregnancy. Validated questionnaires about urinary symptoms during pregnancy, 2 and 12 months after delivery, were administered. Urethral descent was assessed clinically and by ultrasound at inclusion. Multivariate logistic regression analysis was used to determine the risk factors for UI during pregnancy, at 2 months and 1 year after first delivery. The prevalence of UI was 38.6, 46.5, 35.6, and 34.4 % at inclusion, late pregnancy, 2 months postpartum, and 1 year postpartum respectively. No significant association was found between UI at late pregnancy and urethral descent assessed clinically or by ultrasound. The only risk factor for UI at 2 months postpartum was UI at inclusion (OR 6.27 [95 % CI 2.70-14.6]). The risk factors for UI at 1 year postpartum were UI at inclusion (6.14 [2.22-16.9]), body mass index (BMI), and urethral descent at inclusion, assessed clinically (7.21 [2.20-23.7]) or by ultrasound. The mode of delivery was not associated with urethral descent. Prenatal urethral descent and UI during pregnancy are risk factors for UI at 1 year postpartum. These results indicate that postnatal UI is more strongly influenced by susceptibility factors existing before first delivery than by the mode of delivery.

Eye Movement Patterns of the Elderly during Stair Descent:Effect of Illumination

NASA Astrophysics Data System (ADS)

Kasahara, Satoko; Okabe, Sonoko; Nakazato, Naoko; Ohno, Yuko

The relationship between the eye movement pattern during stair descent and illumination was studied in 4 elderly people in comparison with that in 5 young people. The illumination condition was light (85.0±30.9 lx) or dark (0.7±0.3 lx), and data of eye movements were obtained using an eye mark recorder. A flight of 15 steps was used for the experiment, and data on 3 steps in the middle, on which the descent movements were stabilized, were analyzed. The elderly subjects pointed their eyes mostly directly in front in the facial direction regardless of the illumination condition, but the young subjects tended to look down under the light condition. The young subjects are considered to have confirmed the safety of the front by peripheral vision, checked the stepping surface by central vision, and still maintained the upright position without leaning forward during stair descent. The elderly subjects, in contrast, always looked at the visual target by central vision even under the light condition and leaned forward. The range of eye movements was larger vertically than horizontally in both groups, and a characteristic eye movement pattern of repeating a vertical shuttle movement synchronous with descent of each step was observed. Under the dark condition, the young subjects widened the range of vertical eye movements and reduced duration of fixation. The elderly subjects showed no change in the range of eye movements but increased duration of fixation during stair descent. These differences in the eye movements are considered to be compensatory reactions to narrowing of the vertical visual field, reduced dark adaptation, and reduced dynamic visual acuity due to aging. These characteristics of eye movements of the elderly lead to an anteriorly leaned posture and lack of attention to the front during stair descent.

Designing Feature and Data Parallel Stochastic Coordinate Descent Method forMatrix and Tensor Factorization

DTIC Science & Technology

2016-05-11

AFRL-AFOSR-JP-TR-2016-0046 Designing Feature and Data Parallel Stochastic Coordinate Descent Method for Matrix and Tensor Factorization U Kang Korea...maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or   any other aspect...Designing Feature and Data Parallel Stochastic Coordinate Descent Method for Matrix and Tensor Factorization 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386

Using survival analysis to determine association between maternal pelvis height and antenatal fetal head descent in Ugandan mothers.

PubMed

Munabi, Ian Guyton; Luboga, Samuel Abilemech; Mirembe, Florence

2015-01-01

Fetal head descent is used to demonstrate the maternal pelvis capacity to accommodate the fetal head. This is especially important in low resource settings that have high rates of childbirth related maternal deaths and morbidity. This study looked at maternal height and an additional measure, maternal pelvis height, from automotive engineering. The objective of the study was to determine the associations between maternal: height and pelvis height with the rate of fetal head descent in expectant Ugandan mothers. This was a cross sectional study on 1265 singleton mothers attending antenatal clinics at five hospitals in various parts of Uganda. In addition to the routine antenatal examination, each mother had their pelvis height recorded following informed consent. Survival analysis was done using STATA 12. It was found that 27% of mothers had fetal head descent with an incident rate of 0.028 per week after the 25th week of pregnancy. Significant associations were observed between the rate of fetal head descent with: maternal height (Adj Haz ratio 0.93 P < 0.01) and maternal pelvis height (Adj Haz ratio 1.15 P < 0.01). The significant associations observed between maternal: height and pelvis height with rate of fetal head descent, demonstrate a need for further study of maternal pelvis height as an additional decision support tool for screening mothers in low resource settings.

Using survival analysis to determine association between maternal pelvis height and antenatal fetal head descent in Ugandan mothers

PubMed Central

Munabi, Ian Guyton; Luboga, Samuel Abilemech; Mirembe, Florence

2015-01-01

Introduction Fetal head descent is used to demonstrate the maternal pelvis capacity to accommodate the fetal head. This is especially important in low resource settings that have high rates of childbirth related maternal deaths and morbidity. This study looked at maternal height and an additional measure, maternal pelvis height, from automotive engineering. The objective of the study was to determine the associations between maternal: height and pelvis height with the rate of fetal head descent in expectant Ugandan mothers. Methods This was a cross sectional study on 1265 singleton mothers attending antenatal clinics at five hospitals in various parts of Uganda. In addition to the routine antenatal examination, each mother had their pelvis height recorded following informed consent. Survival analysis was done using STATA 12. Results It was found that 27% of mothers had fetal head descent with an incident rate of 0.028 per week after the 25th week of pregnancy. Significant associations were observed between the rate of fetal head descent with: maternal height (Adj Haz ratio 0.93 P < 0.01) and maternal pelvis height (Adj Haz ratio 1.15 P < 0.01). Conclusion The significant associations observed between maternal: height and pelvis height with rate of fetal head descent, demonstrate a need for further study of maternal pelvis height as an additional decision support tool for screening mothers in low resource settings. PMID:26918071

Powered Flight Design and Reconstructed Performance Summary for the Mars Science Laboratory Mission

NASA Technical Reports Server (NTRS)

Sell, Steven; Chen, Allen; Davis, Jody; San Martin, Miguel; Serricchio, Frederick; Singh, Gurkirpal

2013-01-01

The Powered Flight segment of Mars Science Laboratory's (MSL) Entry, Descent, and Landing (EDL) system extends from backshell separation through landing. This segment is responsible for removing the final 0.1% of the kinetic energy dissipated during EDL and culminating with the successful touchdown of the rover on the surface of Mars. Many challenges exist in the Powered Flight segment: extraction of Powered Descent Vehicle from the backshell, performing a 300m divert maneuver to avoid the backshell and parachute, slowing the descent from 85 m/s to 0.75 m/s and successfully lowering the rover on a 7.5m bridle beneath the rocket-powered Descent Stage and gently placing it on the surface using the Sky Crane Maneuver. Finally, the nearly-spent Descent Stage must execute a Flyaway maneuver to ensure surface impact a safe distance from the Rover. This paper provides an overview of the powered flight design, key features, and event timeline. It also summarizes Curiosity's as flown performance on the night of August 5th as reconstructed by the flight team.

Hot Flashes

MedlinePlus

... report menopausal hot flashes than do women of European descent. Hot flashes are less common in women of Japanese and Chinese descent than in white European women. Complications Nighttime hot flashes (night sweats) can ...

Carrier Screening

MedlinePlus

... most common in people of Eastern or Central European Jewish, French Canadian, and Cajun descent. But anyone ... most commonly affects people of Eastern and Central European Jewish, Cajun, and French Canadian descent, but it ...

A refined chronology of prehistoric Madagascar and the demise of the megafauna

NASA Astrophysics Data System (ADS)

Crowley, Brooke E.

2010-09-01

The vertebrate community of Madagascar is one of the most unique and diverse on Earth, yet faunal diversity today is just a fraction of that present in the Pleistocene and Early Holocene. An understanding of the chronology of extinction relative to climate change and anthropogenic factors is essential to test hypotheses for extinction. Here, I combine over 200 new radiocarbon dates with published 14C dates from extinct and extant subfossil vertebrates. These new data provide evidence for the prolonged existence of both extant and extinct endemic terrestrial vertebrate species well before human arrival, with habitation of some localities extending back before the Last Glacial Maximum. I analyze the data for patterns among body sizes and ecoregions in relation to four major historical events: human arrival (ca 2500 years ago), establishment of human settlements (ca 1500 years ago), Late Holocene aridification (peaking ca 1000 years ago), and European arrival (ca 500 years ago). Patterns in endemic species abundance after human arrival differ depending on body size and geographic location. Within the first 500 years after human arrival, there were population declines in (1) very large species (>150 kg) and large species (10-150 kg) in the Dry Deciduous Forest, (2) large species in the Central Highlands, and (3) very large species in the Spiny Thicket. This first pulse of declines was likely triggered by human predation. Large species continued to be well represented in the Spiny Thicket and Succulent Woodland until ca 1000 years ago, when their populations plummeted. This second pulse of declines may have been solely triggered by continued human predation, or it may have resulted from a combination of increasing Late Holocene aridity and human impacts in the form of hunting and habitat modification. The abundance of endemic animals weighing <10 kg increased dramatically in the aftermath of the decline in large-bodied species.

Steel erected at A-3 Test Stand

NASA Technical Reports Server (NTRS)

2008-01-01

Workers erect the first fabricated steel girders to arrive at the A-3 Test Stand at Stennis Space Center. Steel work began at the construction site Oct. 29 and is scheduled to continue into next spring.

Steel erected at A-3 Test Stand

NASA Image and Video Library

2008-10-29

Workers erect the first fabricated steel girders to arrive at the A-3 Test Stand at Stennis Space Center. Steel work began at the construction site Oct. 29 and is scheduled to continue into next spring.

Study on the propagation properties of laser in aerosol based on Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Leng, Kun; Wu, Wenyuan; Zhang, Xi; Gong, Yanchun; Yang, Yuntao

2018-02-01

When laser propagate in the atmosphere, due to aerosol scattering and absorption, laser energy will continue to decline, affecting the effectiveness of the laser effect. Based on the Monte Carlo method, the relationship between the photon spatial energy distributions of the laser wavelengths of 10.6μm in marine, sand-type, water-soluble and soot aerosols ,and the propagation distance, visibility and the divergence angle were studied. The results show that for 10.6μm laser, the maximum number of attenuation of photons arriving at the receiving plane is sand-type aerosol, the minimal attenuation is water soluble aerosol; as the propagation distance increases, the number of photons arriving at the receiving plane decreases; as the visibility increases, the number of photons arriving at the receiving plane increases rapidly and then stabilizes; in the above cases, the photon energy distribution does not deviated from the Gaussian distribution; as the divergence angle increases, the number of photons arriving at the receiving plane is almost unchanged, but the photon energy distribution gradually deviates from the Gaussian distribution.

A Near-Term Concept for Trajectory Based Operations with Air/Ground Data Link Communication

NASA Technical Reports Server (NTRS)

McNally, David; Mueller, Eric; Thipphavong, David; Paielli, Russell; Cheng, Jinn-Hwei; Lee, Chuhan; Sahlman, Scott; Walton, Joe

2010-01-01

An operating concept and required system components for trajectory-based operations with air/ground data link for today's en route and transition airspace is proposed. Controllers are fully responsible for separation as they are today, and no new aircraft equipage is required. Trajectory automation computes integrated solutions to problems like metering, weather avoidance, traffic conflicts and the desire to find and fly more time/fuel efficient flight trajectories. A common ground-based system supports all levels of aircraft equipage and performance including those equipped and not equipped for data link. User interface functions for the radar controller's display make trajectory-based clearance advisories easy to visualize, modify if necessary, and implement. Laboratory simulations (without human operators) were conducted to test integrated operation of selected system components with uncertainty modeling. Results are based on 102 hours of Fort Worth Center traffic recordings involving over 37,000 individual flights. The presence of uncertainty had a marginal effect (5%) on minimum-delay conflict resolution performance, and windfavorable routes had no effect on detection and resolution metrics. Flight plan amendments and clearances were substantially reduced compared to today s operations. Top-of-descent prediction errors are the largest cause of failure indicating that better descent predictions are needed to reliably achieve fuel-efficient descent profiles in medium to heavy traffic. Improved conflict detections for climbing flights could enable substantially more continuous climbs to cruise altitude. Unlike today s Conflict Alert, tactical automation must alert when an altitude amendment is entered, but before the aircraft starts the maneuver. In every other failure case tactical automation prevented losses of separation. A real-time prototype trajectory trajectory-automation system is running now and could be made ready for operational testing at an en route Center in 1-2 years.

Apollo 15 mission report, supplement 4: Descent propulsion system final flight evaluation

NASA Technical Reports Server (NTRS)

Avvenire, A. T.; Wood, S. C.

1972-01-01

The results of a postflight analysis of the LM-10 Descent Propulsion System (DPS) during the Apollo 15 Mission are reported. The analysis determined the steady state performance of the DPS during the descent phase of the manned lunar landing. Flight measurement discrepancies are discussed. Simulated throttle performance results are cited along with overall performance results. Evaluations of the propellant quantity gaging system, propellant loading, pressurization system, and engine are reported. Graphic illustrations of the evaluations are included.

Apollo experience report: Descent propulsion system

NASA Technical Reports Server (NTRS)

Hammock, W. R., Jr.; Currie, E. C.; Fisher, A. E.

1973-01-01

The propulsion system for the descent stage of the lunar module was designed to provide thrust to transfer the fully loaded lunar module with two crewmen from the lunar parking orbit to the lunar surface. A history of the development of this system is presented. Development was accomplished primarily by ground testing of individual components and by testing the integrated system. Unique features of the descent propulsion system were the deep throttling capability and the use of a lightweight cryogenic helium pressurization system.

Cryptorchidism and delayed testicular descent in Florida black bears.

PubMed

Dunbar, M R; Cunningham, M W; Wooding, J B; Roth, R P

1996-10-01

Retained testes were found in 11 (16%) of 71 black bears (Ursus americanus) examined over a 3-year period in Florida (USA). Four of the 11 bears were older than one year and weighed more than 32 kg; therefore, they were considered to be cryptorchid. The remaining seven bears may have had delayed testicular descent due to their apparent normal immature development. This is the first known published report of the prevalence of cryptorchidism and apparently normal delayed testicular descent in a black bear population.

Mars Science Laboratory Entry, Descent and Landing System Development Challenges and Preliminary Flight Performance

NASA Technical Reports Server (NTRS)

Steltzner, Adam D.; San Martin, A. Miguel; Rivellini, Tommaso P.

2013-01-01

The Mars Science Laboratory project recently landed the Curiosity rover on the surface of Mars. With the success of the landing system, the performance envelope of entry, descent, and landing capabilities has been extended over the previous state of the art. This paper will present an overview of the MSL entry, descent, and landing system, a discussion of a subset of its development challenges, and include a discussion of preliminary results of the flight reconstruction effort.

Mars Science Laboratory Descent Stage

NASA Image and Video Library

2011-11-10

The descent stage of NASA Mars Science Laboratory spacecraft is being lifted during assembly of the spacecraft in this photograph taken inside the Payload Hazardous Servicing Facility at NASA Kennedy Space Center, Fla.

Descent Stage of Mars Science Laboratory During Assembly

NASA Image and Video Library

2008-11-19

This image from early October 2008 shows personnel working on the descent stage of NASA Mars Science Laboratory inside the Spacecraft Assembly Facility at NASA Jet Propulsion Laboratory, Pasadena, Calif.

Efficacy of natalizumab therapy in patients of African descent with relapsing multiple sclerosis: analysis of AFFIRM and SENTINEL data.

PubMed

Cree, Bruce A C; Stuart, William H; Tornatore, Carlo S; Jeffery, Douglas R; Pace, Amy L; Cha, Choon H

2011-04-01

Patients with multiple sclerosis (MS) who are of African descent experience a more aggressive disease course than patients who are of white race/ethnicity. In phase 3 clinical trials (Natalizumab Safety and Efficacy in Relapsing Remitting Multiple Sclerosis [AFFIRM] and Safety and Efficacy of Natalizumab in Combination With Interferon Beta-1a in Patients With Relapsing Remitting Multiple Sclerosis [SENTINEL]), natalizumab use significantly improved clinical and magnetic resonance imaging outcomes over 2 years in patients with relapsing MS. Because patients of African descent may be less responsive to interferon beta treatment than patients of white race/ethnicity, the efficacy of natalizumab therapy in this population is clinically important. To evaluate the efficacy of natalizumab use in patients of African descent with relapsing MS. Post hoc analysis. Academic research. Patients of African descent with relapsing MS who received natalizumab or placebo in the phase 3 AFFIRM study and those who received natalizumab plus intramuscular interferon beta-1a or placebo plus intramuscular interferon beta-1a in the phase 3 SENTINEL study. Efficacy of natalizumab use in patients of African descent with relapsing MS who participated in the AFFIRM or SENTINEL trial. Forty-nine patients of African descent participated in AFFIRM (n = 10) or SENTINEL (n = 39). Demographic and baseline disease characteristics were similar between patients treated with natalizumab (n = 21) or placebo (n = 28). Natalizumab therapy significantly reduced the annualized MS relapse rate by 60% (0.21 vs 0.53 in the placebo group, P = .02). Compared with placebo use, natalizumab therapy also significantly reduced the accumulation of lesions observed on magnetic resonance imaging over 2 years: the mean number of gadolinium-enhancing lesions was reduced by 79% (0.19 vs 0.91, P = .03), and the mean number of new or enlarged T2-weighted lesions was reduced by 90% (0.88 vs 8.52, P = .008). Natalizumab therapy significantly improved the relapse rate and accumulation of brain lesions in patients of African descent with relapsing MS.

Measurement of CPAS Main Parachute Rate of Descent

NASA Technical Reports Server (NTRS)

Ray, Eric S.

2011-01-01

The Crew Exploration Vehicle Parachute Assembly System (CPAS) is being designed to land the Orion Crew Module (CM) at a safe rate of descent at splashdown. Flight test performance must be measured to a high degree of accuracy to ensure this requirement is met with the most efficient design possible. Although the design includes three CPAS Main parachutes, the requirement is that the system must not exceed 33 ft/s under two Main parachutes, should one of the Main parachutes fail. Therefore, several tests were conducted with clusters of two Mains. All of the steady-state rate of descent data are normalized to standard sea level conditions and checked against the limit. As the Orion design gains weight, the system is approaching this limit to within measurement precision. Parachute "breathing," cluster interactions, and atmospheric anomalies can cause the rate of descent to vary widely and lead to challenges in characterizing parachute terminal performance. An early test had contradictory rate of descent results from optical trajectory and Differential Global Positioning Systems (DGPS). A thorough analysis of the data sources and error propagation was conducted to determine the uncertainty in the trajectory. It was discovered that the Time Space Position Information (TSPI) from the optical tracking provided accurate position data. However, the velocity from TPSI must be computed via numerical differentiation, which is prone to large error. DGPS obtains position through pseudo-range calculations from multiple satellites and velocity through Doppler shift of the carrier frequency. Because the velocity from DGPS is a direct measurement, it is more accurate than TSPI velocity. To remedy the situation, a commercial off-the-shelf product that combines GPS and an Inertial Measurement Unit (IMU) was purchased to significantly improve rate of descent measurements. This had the added benefit of solving GPS dropouts during aircraft extraction. Statistical probability distributions for CPAS Main parachute rate of descent and drag coefficient were computed and plotted. Using test data, a terminal rate of descent at splashdown can be estimated as a function of canopy loading.

Mars Science Laboratory Rover and Descent Stage

NASA Image and Video Library

2008-11-19

In this February 17, 2009, image, NASA Mars Science Laboratory rover is attached to the spacecraft descent stage. The image was taken inside the Spacecraft Assembly Facility at NASA JPL, Pasadena, Calif.

40 CFR 161.175 - Certified limits.

Code of Federal Regulations, 2010 CFR

2010-07-01

... how the certified limits were arrived at (e.g., sample analysis, quantitative estimate based on....175 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Product Chemistry Data Requirements § 161.175...

Simulation and analysis of traffic flow based on cellular automaton

NASA Astrophysics Data System (ADS)

Ren, Xianping; Liu, Xia

2018-03-01

In this paper, single-lane and two-lane traffic model are established based on cellular automaton. Different values of vehicle arrival rate at the entrance and vehicle departure rate at the exit are set to analyze their effects on density, average speed and traffic flow. If the road exit is unblocked, vehicles can pass through the road smoothly despite of the arrival rate at the entrance. If vehicles enter into the road continuously, the traffic condition is varied with the departure rate at the exit. To avoid traffic jam, reasonable vehicle departure rate should be adopted.

Kawasaki Disease

MedlinePlus

... descent. The disease is more likely to affect boys than girls. Most cases occur in children younger than 5 ... descent. The disease is more likely to affect boys than girls. Most cases occur in children younger than 5 ...

Dynamic ground-effect measurements on the F-15 STOL and Maneuver Technology Demonstrator (S/MTD) configuration

NASA Technical Reports Server (NTRS)

Kemmerly, Guy T.

1990-01-01

A moving-model ground-effect testing method was used to study the influence of rate-of-descent on the aerodynamic characteristics for the F-15 STOL and Maneuver Technology Demonstrator (S/MTD) configuration for both the approach and roll-out phases of landing. The approach phase was modeled for three rates of descent, and the results were compared to the predictions from the F-15 S/MTD simulation data base (prediction based on data obtained in a wind tunnel with zero rate of descent). This comparison showed significant differences due both to the rate of descent in the moving-model test and to the presence of the ground boundary layer in the wind tunnel test. Relative to the simulation data base predictions, the moving-model test showed substantially less lift increase in ground effect, less nose-down pitching moment, and less increase in drag. These differences became more prominent at the larger thrust vector angles. Over the small range of rates of descent tested using the moving-model technique, the effect of rate of descent on longitudinal aerodynamics was relatively constant. The results of this investigation indicate no safety-of-flight problems with the lower jets vectored up to 80 deg on approach. The results also indicate that this configuration could employ a nozzle concept using lower reverser vector angles up to 110 deg on approach if a no-flare approach procedure were adopted and if inlet reingestion does not pose a problem.

Gentle Africanized bees on an oceanic island

PubMed Central

Rivera-Marchand, Bert; Oskay, Devrim; Giray, Tugrul

2012-01-01

Oceanic islands have reduced resources and natural enemies and potentially affect life history traits of arriving organisms. Among the most spectacular invasions in the Western hemisphere is that of the Africanized honeybee. We hypothesized that in the oceanic island Puerto Rico, Africanized bees will exhibit differences from the mainland population such as for defensiveness and other linked traits. We evaluated the extent of Africanization through three typical Africanized traits: wing size, defensive behavior, and resistance to Varroa destructor mites. All sampled colonies were Africanized by maternal descent, with over 65% presence of European alleles at the S-3 nuclear locus. In two assays evaluating defense, Puerto Rican bees showed low defensiveness similar to European bees. In morphology and resistance to mites, Africanized bees from Puerto Rico are similar to other Africanized bees. In behavioral assays on mechanisms of resistance to Varroa, we directly observed that Puerto Rican Africanized bees groomed-off and bit the mites as been observed in other studies. In no other location, Africanized bees have reduced defensiveness while retaining typical traits such as wing size and mite resistance. This mosaic of traits that has resulted during the invasion of an oceanic island has implications for behavior, evolution, and agriculture. PMID:23144660

KSC-2012-4169

NASA Image and Video Library

2012-08-01

CAPE CANAVERAL, Fla. - At a hangar near the Shuttle Landing Facility, or SLF, at NASA’s Kennedy Space Center in Florida, Chirold Epp, Johnson Space Center Project Manager for ALHAT, speaks to members of the media. In the background is the Morpheus prototype lander, which arrived at Kennedy on July 27. Testing of the prototype lander had been ongoing at NASA’s Johnson Space Center in Houston in preparation for its first free-flight test at Kennedy Space Center. The SLF will provide the lander with the kind of field necessary for realistic testing, complete with rocks, craters and hazards to avoid. Morpheus utilizes an autonomous landing and hazard avoidance technology, or ALHAT, payload that will allow it to navigate to clear landing sites amidst rocks, craters and other hazards during its descent. Project Morpheus is one of 20 small projects comprising the Advanced Exploration Systems, or AES, program in NASA’s Human Exploration and Operations Mission Directorate. AES projects pioneer new approaches for rapidly developing prototype systems, demonstrating key capabilities and validating operational concepts for future human missions beyond Earth orbit. For more information on Project Morpheus, visit http://morpheuslander.jsc.nasa.gov/. Photo credit: NASA/Kim Shiflett

KSC-2012-4167

NASA Image and Video Library

2012-08-01

CAPE CANAVERAL, Fla. - At a hangar near the Shuttle Landing Facility, or SLF, at NASA’s Kennedy Space Center in Florida, the Johnson Space Center Project Morpheus Manager Jon Olansen speaks to members of the media. In the foreground is the Morpheus prototype lander, which arrived at Kennedy on July 27. Testing of the prototype lander had been ongoing at NASA’s Johnson Space Center in Houston in preparation for its first free-flight test at Kennedy Space Center. The SLF will provide the lander with the kind of field necessary for realistic testing, complete with rocks, craters and hazards to avoid. Morpheus utilizes an autonomous landing and hazard avoidance technology, or ALHAT, payload that will allow it to navigate to clear landing sites amidst rocks, craters and other hazards during its descent. Project Morpheus is one of 20 small projects comprising the Advanced Exploration Systems, or AES, program in NASA’s Human Exploration and Operations Mission Directorate. AES projects pioneer new approaches for rapidly developing prototype systems, demonstrating key capabilities and validating operational concepts for future human missions beyond Earth orbit. For more information on Project Morpheus, visit http://morpheuslander.jsc.nasa.gov/. Photo credit: NASA/Kim Shiflett

KSC-2012-4168

NASA Image and Video Library

2012-08-01

CAPE CANAVERAL, Fla. - At a hangar near the Shuttle Landing Facility, or SLF, at NASA’s Kennedy Space Center in Florida, the Johnson Space Center Project Morpheus Manager Jon Olansen speaks to members of the media. In the background is the Morpheus prototype lander, which arrived at Kennedy on July 27. Testing of the prototype lander had been ongoing at NASA’s Johnson Space Center in Houston in preparation for its first free-flight test at Kennedy Space Center. The SLF will provide the lander with the kind of field necessary for realistic testing, complete with rocks, craters and hazards to avoid. Morpheus utilizes an autonomous landing and hazard avoidance technology, or ALHAT, payload that will allow it to navigate to clear landing sites amidst rocks, craters and other hazards during its descent. Project Morpheus is one of 20 small projects comprising the Advanced Exploration Systems, or AES, program in NASA’s Human Exploration and Operations Mission Directorate. AES projects pioneer new approaches for rapidly developing prototype systems, demonstrating key capabilities and validating operational concepts for future human missions beyond Earth orbit. For more information on Project Morpheus, visit http://morpheuslander.jsc.nasa.gov/. Photo credit: NASA/Kim Shiflett

[Ethnic origin and alveolar bone loss in Israeli adults].

PubMed

Zadik, Y; Bechor, R; Shochat, Z; Galor, S

2008-04-01

The aim of this study was to evaluate the association of alveolar bone loss and ethnic origin among Israeli adults. The study population consisted of 815 male military personnel, aged 25 to 60 years (average 38.1 +/- 7.0 yr), who arrived at a military dental clinic for routine dental examination during 2004-5. The distance between CEJ and alveolar bone crest was measure on pair of standardized posterior bitewing radiographs. Associations between the periodontal score and place of birth, the father ethnic origin and the mother ethnic origin were evaluated using the chi2-test. The individual's place of birth had no influence on the radiographic alveolar bone loss. Father of Yemenite-, North-African- or Mediterranean-origin, and mother of Yemenite-, North-African- or Asian-origin have associated to the occurrence and severity of alveolar bone loss, whereas sons to father or mother from Israeli or European descent were found to have less bone loss (p < 0.001). Ethnic origin has an influence on the alveolar bone loss in Israeli adults. However, more research is needed on the role of the potentially confounders in the association between origin and periodontal health.

East Eurasian ancestry in the middle of Europe: genetic footprints of Steppe nomads in the genomes of Belarusian Lipka Tatars

PubMed Central

Pankratov, Vasili; Litvinov, Sergei; Kassian, Alexei; Shulhin, Dzmitry; Tchebotarev, Lieve; Yunusbayev, Bayazit; Möls, Märt; Sahakyan, Hovhannes; Yepiskoposyan, Levon; Rootsi, Siiri; Metspalu, Ene; Golubenko, Maria; Ekomasova, Natalia; Akhatova, Farida; Khusnutdinova, Elza; Heyer, Evelyne; Endicott, Phillip; Derenko, Miroslava; Malyarchuk, Boris; Metspalu, Mait; Davydenko, Oleg; Villems, Richard; Kushniarevich, Alena

2016-01-01

Medieval era encounters of nomadic groups of the Eurasian Steppe and largely sedentary East Europeans had a variety of demographic and cultural consequences. Amongst these outcomes was the emergence of the Lipka Tatars—a Slavic-speaking Sunni-Muslim minority residing in modern Belarus, Lithuania and Poland, whose ancestors arrived in these territories via several migration waves, mainly from the Golden Horde. Our results show that Belarusian Lipka Tatars share a substantial part of their gene pool with Europeans as indicated by their Y-chromosomal, mitochondrial and autosomal DNA variation. Nevertheless, Belarusian Lipkas still retain a strong genetic signal of their nomadic ancestry, witnessed by the presence of common Y-chromosomal and mitochondrial DNA variants as well as autosomal segments identical by descent between Lipkas and East Eurasians from temperate and northern regions. Hence, we document Lipka Tatars as a unique example of former Medieval migrants into Central Europe, who became sedentary, changed language to Slavic, yet preserved their faith and retained, both uni- and bi-parentally, a clear genetic echo of a complex population interplay throughout the Eurasian Steppe Belt, extending from Central Europe to northern China. PMID:27453128

Genetic concepts in Greek literature from the eighth to the fourth century B.C.

PubMed

Bazopoulou-Kyrkanidou, E

1992-03-01

A review of the concepts of genetics found in epic, historical and dramatic ancient Greek writings from the eighth to the fourth centuries B.C., is presented. The derived data suggest that the development of genetical concepts and ideas started with the praise of the heroes' divine or noble origin in Homer's epic poems (eighth century B.C.). It continued in the tracing of the descent and vicissitudes of the families of the Greek gods and the common ancestry of the Greek tribes as described in Hesiod's genealogical poems (around 700 B.C.), in the statement of descent and dual parenthood of leaders and kings in the books of Herodotus and Xenophon (fifth and fourth centuries B.C.), and in the concern about the lineage of the tragic figures in Greek drama (fifth century B.C.). The genetical concepts expressed in these writings most probably reflected popular notions of that time. They must, therefore, have been the basis of the perceptions and theories on heredity and procreation expressed by the ancient physicians and philosophers in the fifth and fourth centuries B.C., which in turn influenced the development of genetics for many centuries.

Foot and Ankle Kinematics During Descent From Varying Step Heights.

PubMed

Gerstle, Emily E; O'Connor, Kristian; Keenan, Kevin G; Cobb, Stephen C

2017-12-01

In the general population, one-third of incidences during step negotiation occur during the transition to level walking. Furthermore, falls during curb negotiation are a common cause of injury in older adults. Distal foot kinematics may be an important factor in determining injury risk associated with transition step negotiation. The purpose of this study was to identify foot and ankle kinematics of uninjured individuals during descent from varying step heights. A 7-segment foot model was used to quantify kinematics as participants walked on a level walkway, stepped down a single step (heights: 5 cm, 15 cm, 25 cm), and continued walking. As step height increased, landing strategy transitioned from the rearfoot to the forefoot, and the rearfoot, lateral and medial midfoot, and medial forefoot became more plantar flexed. During weight acceptance, sagittal plane range of motion of the rearfoot, lateral midfoot, and medial and lateral forefoot increased as step height increased. The changes in landing strategy and distal foot function suggest a less stable ankle position at initial contact and increased demand on the distal foot at initial contact and through the weight acceptance phase of transition step negotiation as step height increases.

Knowledge-Based Scheduling of Arrival Aircraft in the Terminal Area

NASA Technical Reports Server (NTRS)

Krzeczowski, K. J.; Davis, T.; Erzberger, H.; Lev-Ram, Israel; Bergh, Christopher P.

1995-01-01

A knowledge based method for scheduling arrival aircraft in the terminal area has been implemented and tested in real time simulation. The scheduling system automatically sequences, assigns landing times, and assign runways to arrival aircraft by utilizing continuous updates of aircraft radar data and controller inputs. The scheduling algorithm is driven by a knowledge base which was obtained in over two thousand hours of controller-in-the-loop real time simulation. The knowledge base contains a series of hierarchical 'rules' and decision logic that examines both performance criteria, such as delay reductions, as well as workload reduction criteria, such as conflict avoidance. The objective of the algorithm is to devise an efficient plan to land the aircraft in a manner acceptable to the air traffic controllers. This paper describes the scheduling algorithms, gives examples of their use, and presents data regarding their potential benefits to the air traffic system.

Knowledge-based scheduling of arrival aircraft

NASA Technical Reports Server (NTRS)

Krzeczowski, K.; Davis, T.; Erzberger, H.; Lev-Ram, I.; Bergh, C.

1995-01-01

A knowledge-based method for scheduling arrival aircraft in the terminal area has been implemented and tested in real-time simulation. The scheduling system automatically sequences, assigns landing times, and assigns runways to arrival aircraft by utilizing continuous updates of aircraft radar data and controller inputs. The scheduling algorithms is driven by a knowledge base which was obtained in over two thousand hours of controller-in-the-loop real-time simulation. The knowledge base contains a series of hierarchical 'rules' and decision logic that examines both performance criteria, such as delay reduction, as well as workload reduction criteria, such as conflict avoidance. The objective of the algorithms is to devise an efficient plan to land the aircraft in a manner acceptable to the air traffic controllers. This paper will describe the scheduling algorithms, give examples of their use, and present data regarding their potential benefits to the air traffic system.

Bayesian analysis of Jolly-Seber type models

USGS Publications Warehouse

Matechou, Eleni; Nicholls, Geoff K.; Morgan, Byron J. T.; Collazo, Jaime A.; Lyons, James E.

2016-01-01

We propose the use of finite mixtures of continuous distributions in modelling the process by which new individuals, that arrive in groups, become part of a wildlife population. We demonstrate this approach using a data set of migrating semipalmated sandpipers (Calidris pussila) for which we extend existing stopover models to allow for individuals to have different behaviour in terms of their stopover duration at the site. We demonstrate the use of reversible jump MCMC methods to derive posterior distributions for the model parameters and the models, simultaneously. The algorithm moves between models with different numbers of arrival groups as well as between models with different numbers of behavioural groups. The approach is shown to provide new ecological insights about the stopover behaviour of semipalmated sandpipers but is generally applicable to any population in which animals arrive in groups and potentially exhibit heterogeneity in terms of one or more other processes.

Spread of cattle led to the loss of matrilineal descent in Africa: a coevolutionary analysis.

PubMed Central

Holden, Clare Janaki; Mace, Ruth

2003-01-01

Matrilineal descent is rare in human societies that keep large livestock. However, this negative correlation does not provide reliable evidence that livestock and descent rules are functionally related, because human cultures are not statistically independent owing to their historical relationships (Galton's problem). We tested the hypothesis that when matrilineal cultures acquire cattle they become patrilineal using a sample of 68 Bantu- and Bantoid-speaking populations from sub-Saharan Africa. We used a phylogenetic comparative method to control for Galton's problem, and a maximum-parsimony Bantu language tree as a model of population history. We tested for coevolution between cattle and descent. We also tested the direction of cultural evolution--were cattle acquired before matriliny was lost? The results support the hypothesis that acquiring cattle led formerly matrilineal Bantu-speaking cultures to change to patrilineal or mixed descent. We discuss possible reasons for matriliny's association with horticulture and its rarity in pastoralist societies. We outline the daughter-biased parental investment hypothesis for matriliny, which is supported by data on sex, wealth and reproductive success from two African societies, the matrilineal Chewa in Malawi and the patrilineal Gabbra in Kenya. PMID:14667331

Experimental studies of the rotor flow downwash on the Stability of multi-rotor crafts in descent

NASA Astrophysics Data System (ADS)

Veismann, Marcel; Dougherty, Christopher; Gharib, Morteza

2017-11-01

All rotorcrafts, including helicopters and multicopters, have the inherent problem of entering rotor downwash during vertical descent. As a result, the craft is subject to highly unsteady flow, called vortex ring state (VRS), which leads to a loss of lift and reduced stability. To date, experimental efforts to investigate this phenomenon have been largely limited to analysis of a single, fixed rotor mounted in a horizontal wind tunnel. Our current work aims to understand the interaction of multiple rotors in vertical descent by mounting a multi-rotor craft in a low speed, vertical wind tunnel. Experiments were performed with a fixed and rotationally free mounting; the latter allowing us to better capture the dynamics of a free flying drone. The effect of rotor separation on stability, generated thrust, and rotor wake interaction was characterized using force gauge data and PIV analysis for various descent velocities. The results obtained help us better understand fluid-craft interactions of drones in vertical descent and identify possible sources of instability. The presented material is based upon work supported by the Center for Autonomous Systems and Technologies (CAST) at the Graduate Aerospace Laboratories of the California Institute of Technology (GALCIT).

'The full has never been told': building a theory of sexual health for heterosexual Black men of Caribbean descent.

PubMed

Crowell, Candice N; Delgado-Romero, Edward A; Mosley, Della V; Huynh, Sophia

2016-08-01

Research on Black sexual health often fails to represent the heterogeneity of Black ethnic groups. For people of Caribbean descent in the USA, ethnicity is a salient cultural factor that influences definitions and experiences of sexual health. Most research on people of Caribbean descent focuses on the relatively high rate of STIs, but sexual health is defined more broadly than STI prevalence. Psychological and emotional indicators and the voice of participants are important to consider when exploring the sexual health of a minority culture. The purpose of this study was to qualitatively explore how heterosexual Black men of Caribbean descent define and understand sexual health for themselves. Eleven men who self-identified as Black, Caribbean and heterosexual participated in three focus groups and were asked to define sexual health, critique behaviours expertly identified as healthy and address what encourages and discourages sexual health in their lives. Findings point to six dimensions of sexual health for heterosexual Black men of Caribbean descent. These include: heterosexually privileged, protective, contextual, interpersonal, cultural and pleasurable dimensions. There were some notable departures from current expert definitions of sexual health. Recommendations for further theory development are provided.

School Librarian, Teacher Collaborator, and Independent Learner: A Symbiosis for Equitable Education in an Alternative High School

ERIC Educational Resources Information Center

Jaaskelainen, Kristal; Deneen, Musetta

2018-01-01

As the future arrives faster and faster one must ask continually, what do kids actually need from their formal education today and tomorrow? Continuous innovation of method and strategy must be integral to the practice of all teaching professionals. Equitable educators must take a look at the learners in front of them, when and where they stand,…

Feature Clustering for Accelerating Parallel Coordinate Descent

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

Scherrer, Chad; Tewari, Ambuj; Halappanavar, Mahantesh

2012-12-06

We demonstrate an approach for accelerating calculation of the regularization path for L1 sparse logistic regression problems. We show the benefit of feature clustering as a preconditioning step for parallel block-greedy coordinate descent algorithms.

2007 Mars Phoenix Entry, Descent, and Landing Simulation and Modeling Analysis

NASA Technical Reports Server (NTRS)

Prince, Jill L.; Grover, Myron R.; Desai, Prasun N.; Queen, Eric M.

2007-01-01

This viewgraph presentation reviews the entry, descent, and landing of the 2007 Mars Phoenix lander. Aerodynamics characteristics along with Monte Carlo analyses are also presented for launch and landing site opportunities.

Entry, Descent, and Landing With Propulsive Deceleration

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan

2012-01-01

The future exploration of the Solar System will require innovations in transportation and the use of entry, descent, and landing (EDL) systems at many planetary landing sites. The cost of space missions has always been prohibitive, and using the natural planetary and planet s moons atmospheres for entry, descent, and landing can reduce the cost, mass, and complexity of these missions. This paper will describe some of the EDL ideas for planetary entry and survey the overall technologies for EDL that may be attractive for future Solar System missions.

Gradient optimization and nonlinear control

NASA Technical Reports Server (NTRS)

Hasdorff, L.

1976-01-01

The book represents an introduction to computation in control by an iterative, gradient, numerical method, where linearity is not assumed. The general language and approach used are those of elementary functional analysis. The particular gradient method that is emphasized and used is conjugate gradient descent, a well known method exhibiting quadratic convergence while requiring very little more computation than simple steepest descent. Constraints are not dealt with directly, but rather the approach is to introduce them as penalty terms in the criterion. General conjugate gradient descent methods are developed and applied to problems in control.

Orion Heat Shield

NASA Image and Video Library

2015-03-09

THE ORION HEAT SHIELD THAT SUCCESSFULLY SURVIVED A HIGH-VELOCITY REENTRY DURING ITS DEC. 5 FLIGHT TEST, IS CONTINUING ITS JOURNEY, NOW AT MARSHALL. IT ARRIVED ON MONDAY, MARCH 9 AND WILL BE INSTALLED IN THE BUILDING 4705 7-AXIS MILLING AND MACHINING CENTER.

Cardiovascular disease, diabetes and established risk factors among populations of sub-Saharan African descent in Europe: a literature review

PubMed Central

Agyemang, Charles; Addo, Juliet; Bhopal, Raj; de Graft Aikins, Ama; Stronks, Karien

2009-01-01

Background Most European countries are ethnically and culturally diverse. Globally, cardiovascular disease (CVD) is the leading cause of death. The major risk factors for CVD have been well established. This picture holds true for all regions of the world and in different ethnic groups. However, the prevalence of CVD and related risk factors vary among ethnic groups. Methods This article provides a review of current understanding of the epidemiology of vascular disease, principally coronary heart disease (CHD), stroke and related risk factors among populations of Sub-Sahara African descent (henceforth, African descent) in comparison with the European populations in Europe. Results Compared with European populations, populations of African descent have an increased risk of stroke, whereas CHD is less common. They also have higher rates of hypertension and diabetes than European populations. Obesity is highly prevalent, but smoking rate is lower among African descent women. Older people of African descent have more favourable lipid profile and dietary habits than their European counterparts. Alcohol consumption is less common among populations of African descent. The rate of physical activity differs between European countries. Dutch African-Suriname men and women are less physically active than the White-Dutch whereas British African women are more physically active than women in the general population. Literature on psychosocial stress shows inconsistent results. Conclusion Hypertension and diabetes are highly prevalent among African populations, which may explain their high rate of stroke in Europe. The relatively low rate of CHD may be explained by the low rates of other risk factors including a more favourable lipid profile and the low prevalence of smoking. The risk factors are changing, and on the whole, getting worse especially among African women. Cohort studies and clinical trials are therefore needed among these groups to determine the relative contribution of vascular risk factors, and to help guide the prevention efforts. There is a clear need for intervention studies among these populations in Europe. PMID:19671137

Assessing the ability to derive rates of polar middle-atmospheric descent using trace gas measurements from remote sensors

NASA Astrophysics Data System (ADS)

Ryan, Niall J.; Kinnison, Douglas E.; Garcia, Rolando R.; Hoffmann, Christoph G.; Palm, Mathias; Raffalski, Uwe; Notholt, Justus

2018-02-01

We investigate the reliability of using trace gas measurements from remote sensing instruments to infer polar atmospheric descent rates during winter within 46-86 km altitude. Using output from the Specified Dynamics Whole Atmosphere Community Climate Model (SD-WACCM) between 2008 and 2014, tendencies of carbon monoxide (CO) volume mixing ratios (VMRs) are used to assess a common assumption of dominant vertical advection of tracers during polar winter. The results show that dynamical processes other than vertical advection are not negligible, meaning that the transport rates derived from trace gas measurements do not represent the mean descent of the atmosphere. The relative importance of vertical advection is lessened, and exceeded by other processes, during periods directly before and after a sudden stratospheric warming, mainly due to an increase in eddy transport. It was also found that CO chemistry cannot be ignored in the mesosphere due to the night-time layer of OH at approximately 80 km altitude. CO VMR profiles from the Kiruna Microwave Radiometer and the Microwave Limb Sounder were compared to SD-WACCM output, and show good agreement on daily and seasonal timescales. SD-WACCM CO profiles are combined with the CO tendencies to estimate errors involved in calculating the mean descent of the atmosphere from remote sensing measurements. The results indicate errors on the same scale as the calculated descent rates, and that the method is prone to a misinterpretation of the direction of air motion. The true rate of atmospheric descent is seen to be masked by processes, other than vertical advection, that affect CO. We suggest an alternative definition of the rate calculated using remote sensing measurements: not as the mean descent of the atmosphere, but as an effective rate of vertical transport for the trace gas under observation.

Mars Descent Imager for Curiosity

NASA Image and Video Library

2010-07-19

A pocketknife provides scale for this image of the Mars Descent Imager camera; the camera will fly on the Curiosity rover of NASA Mars Science Laboratory mission. Malin Space Science Systems, San Diego, Calif., supplied the camera for the mission.

Death eaters respond to the dark mark of decomposition day and night: observations of initial insect activity on piglet carcasses.

PubMed

Weidner, Lauren M; Monzon, Michael A; Hamilton, George C

2016-11-01

Some insect taxa can be of critical importance for criminal investigations because they can be used to assist with a time since death determination. Blow flies (Diptera: Calliphoridae) often are the initial colonizers of a carcass, usually arriving within minutes to hours after carcass exposure during the day. Other insects, such as coleopterans and hymenopterans, can arrive to a carcass during early colonization and affect blow fly development. However, the extent of these interactions remains unclear. This study analyzed the initial 6 h after a piglet carcass was placed out in two locations (rural and urban) in diurnal and nocturnal conditions with continuous video recording and hourly observations. Four piglets were placed out every 2 weeks over the summer of 2014. Initial blow fly arrivals to the carcasses were only recorded during diurnal conditions, and a checklist of orders associated with each environment (time and location) was created. During diurnal conditions, initial blow fly arrival times in rural environments were significantly faster than those in urban, arriving as quickly as 23 s after exposure. These observations also included a novel interaction with Vespidae, which to the best of our knowledge has not been seen in the literature before. This experiment provides baseline data on early insect colonization in two environments in New Jersey, and lends insight into insect interactions that could affect initial colonization.

Descent and Landing Triggers for the Orion Multi-Purpose Crew Vehicle Exploration Flight Test-1

NASA Technical Reports Server (NTRS)

Bihari, Brian D.; Semrau, Jeffrey D.; Duke, Charity J.

2013-01-01

The Orion Multi-Purpose Crew Vehicle (MPCV) will perform a flight test known as Exploration Flight Test-1 (EFT-1) currently scheduled for 2014. One of the primary functions of this test is to exercise all of the important Guidance, Navigation, Control (GN&C), and Propulsion systems, along with the flight software for future flights. The Descent and Landing segment of the flight is governed by the requirements levied on the GN&C system by the Landing and Recovery System (LRS). The LRS is a complex system of parachutes and flight control modes that ensure that the Orion MPCV safely lands at its designated target in the Pacific Ocean. The Descent and Landing segment begins with the jettisoning of the Forward Bay Cover and concludes with sensing touchdown. This paper discusses the requirements, design, testing, analysis and performance of the current EFT-1 Descent and Landing Triggers flight software.

Natural course of undescended testes after inguinoscrotal surgery.

PubMed

Meij-deVries, Annebeth; van der Voort, Laszla M; Sijstermans, Karlijn; Meijer, Robert W; van der Plas, Evelyn M; Hack, Wilfried W M

2013-12-01

The purpose of the study is to study the natural course of undescended testes after inguinoscrotal surgery. From 2003-2010, 24 boys were observed with 26 undescended testes after inguinoscrotal surgery; 12 had previously undergone inguinal hernia repair and 12 orchidopexy. Spontaneous descent was awaited and (re-)orchidopexy would only be performed in case of non-descent at puberty. The boys were assessed annually for testis position and for testis volume as measured by ultrasound. At the end of the study period, 19 testes had reached scrotal position; of these, 13 (68%) had descended spontaneously and 6 (32%) had been (re-)orchidopexied. No difference was found in the rate of spontaneous descent after previous orchidopexy or inguinal hernia repair (P=0.419). Spontaneous descent of undescended testes after inguinoscrotal surgery occurs regularly. In this study, it was observed in two out of every three cases. © 2013.

Entry, Descent, and Landing Performance for a Mid-Lift-to-Drag Ratio Vehicle at Mars

NASA Technical Reports Server (NTRS)

Johnson, Breanna J.; Braden, Ellen M.; Sostaric, Ronald R.; Cerimele, Christopher J.; Lu, Ping

2018-01-01

In an effort to mature the design of the Mid-Lift-to-Drag ratio Rigid Vehicle (MRV) candidate of the NASA Evolvable Mars Campaign (EMC) architecture study, end-to-end six-degree-of-freedom (6DOF) simulations are needed to ensure a successful entry, descent, and landing (EDL) design. The EMC study is assessing different vehicle and mission architectures to determine which candidate would be best to deliver a 20 metric ton payload to the surface of Mars. Due to the large mass payload and the relatively low atmospheric density of Mars, all candidates of the EMC study propose to use Supersonic Retro-Propulsion (SRP) throughout the descent and landing phase, as opposed to parachutes, in order to decelerate to a subsonic touchdown. This paper presents a 6DOF entry-to-landing performance and controllability study with sensitivities to dispersions, particularly in the powered descent and landing phases.

POST2 End-To-End Descent and Landing Simulation for the Autonomous Landing and Hazard Avoidance Technology Project

NASA Technical Reports Server (NTRS)

Fisher, Jody l.; Striepe, Scott A.

2007-01-01

The Program to Optimize Simulated Trajectories II (POST2) is used as a basis for an end-to-end descent and landing trajectory simulation that is essential in determining the design and performance capability of lunar descent and landing system models and lunar environment models for the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. This POST2-based ALHAT simulation provides descent and landing simulation capability by integrating lunar environment and lander system models (including terrain, sensor, guidance, navigation, and control models), along with the data necessary to design and operate a landing system for robotic, human, and cargo lunar-landing success. This paper presents the current and planned development and model validation of the POST2-based end-to-end trajectory simulation used for the testing, performance and evaluation of ALHAT project system and models.

Gender differences of sagittal knee and ankle biomechanics during stair-to-ground descent transition.

PubMed

Hong, Yoon No Gregory; Shin, Choongsoo S

2015-12-01

Falls on stairs often result in severe injury and occur twice as frequently in women. However, gender differences in kinetics and kinematics during stair descent are unknown. Thus, this study aimed to determine whether gender differences of knee and ankle biomechanics exist in the sagittal plane during the stair-to-ground descending transition. It was hypothesized that 1) women would reveal higher ground-toe-trochanter angle and lower ground-toe length during stair-to-ground descent transition than men; and 2) women would reveal lower peak knee extension moment during stair-to-ground descent transition than men. Fifteen men and fifteen women were recruited and performed a stair descent activity. Kinetic and kinematic data were obtained using a force plate and motion capture system. The women performed the stair descent with a lower peak knee extension moment and a peak knee power at the early weight acceptance phase. The women also revealed a higher ground-toe-trochanter angle and a lower ground-toe length, which indicated a more forward position of the lower extremity relative to the toe contact point at both the initial contact and at the time of peak kinematic and kinetic events. This study found that knee and ankle kinematics and kinetics differed significantly between the genders due to differences in ground-toe-trochanter angle. Women have a different stair descending strategy that reduces the demand of the lower extremity muscle function, but this strategy seems to increase the risk of falls. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of race on the professional lives of physicians of African descent.

PubMed

Nunez-Smith, Marcella; Curry, Leslie A; Bigby, JudyAnn; Berg, David; Krumholz, Harlan M; Bradley, Elizabeth H

2007-01-02

Increasing the racial and ethnic diversity of the physician workforce is a national priority. However, insight into the professional experiences of minority physicians is limited. This knowledge is fundamental to developing effective strategies to recruit, retain, and support a diverse physician workforce. To characterize how physicians of African descent experience race in the workplace. Qualitative study based on in-person and in-depth racially concordant interviews using a standard discussion guide. The 6 New England states in the United States. 25 practicing physicians of African descent representing a diverse range of primary practice settings, specialties, and ages. Professional experiences of physicians of African descent. 1) Awareness of race permeates the experience of physicians of African descent in the health care workplace; 2) race-related experiences shape interpersonal interactions and define the institutional climate; 3) responses to perceived racism at work vary along a spectrum from minimization to confrontation; 4) the health care workplace is often silent on issues of race; and 5) collective race-related experiences can result in "racial fatigue," with personal and professional consequences for physicians. The study was restricted to New England and may not reflect the experiences of physicians in other geographic regions. The findings are meant to be hypothesis-generating and require additional follow-up studies. The issue of race remains a pervasive influence in the work lives of physicians of African descent. Without sufficient attention to the specific ways in which race shapes physicians' work experiences, health care organizations are unlikely to create environments that successfully foster and sustain a diverse physician workforce.

Fish-eye View of NASA Curiosity Rover and its Powered Descent Vehicle

NASA Image and Video Library

2011-11-23

An engineer says goodbye to the Curiosity rover and its powered descent vehicle in the Jet Propulsion Laboratory Spacecraft Assembly Facility shortly before the spacecraft was readied for shipment to Kennedy Space Center for launch.

Integrating Powered Descent Vehicle with Back Shell of Mars Spacecraft

NASA Image and Video Library

2011-11-10

The powered descent vehicle of NASA Mars Science Laboratory spacecraft is being prepared for final integration into the spacecraft back shell in this photograph from inside the Payload Hazardous Servicing Facility at NASA Kennedy Space Center, Fla.

Test Image by Mars Descent Imager

NASA Image and Video Library

2010-07-19

Ken Edgett, deputy principal investigator for NASA Mars Descent Imager, holds a ruler used as a depth-of-field test target. The instrument took this image inside the Malin Space Science Systems clean room in San Diego, CA, during calibration testing.

Men of African Descent and Carcinoma of the Prostate Consortium

Cancer.gov

The Men of African Descent and Carcinoma of the Prostate Consortium collaborates on epidemiologic studies to address the high burden of prostate cancer and to understand the causes of etiology and outcomes among men of African ancestry.

Application of biological filters in water treatment systems

NASA Technical Reports Server (NTRS)

Hurley, T. L.; Bambenek, R. A.

1973-01-01

Silver chloride placed on or close to barrier kills bacteria as they arrive. Dead bacteria accumulate linearly, whereas previously, live bacteria accumulated exponentially. During continuous 30-day tests, no bacteriological contamination was found downstream of filters with silver chloride added.

Prevalence of chronic kidney disease and comorbidities in isolated African descent communities (PREVRENAL): methodological design of a cohort study.

PubMed

Salgado-Filho, Natalino; Lages, Joyce Santos; Brito, Dyego José; Salgado, João Victor; Silva, Gyl Eanes; Santos, Alcione Miranda; Monteiro-Júnior, Francisco Chagas; Santos, Elisangela Milhomen; Silva, Antônio Augusto; Araújo, Denizar Vianna; Sesso, Ricardo Castro

2018-02-26

Chronic kidney disease (CKD) is considered a serious public health problem, both in Brazil and worldwide, with an increasing number of cases observed inrecent years. Especially, CKD has been reported to be highly prevalent in those of African descent. However, Brazil lacks data from early-stage CKD population studies, and the prevalence of CKD is unknown for both the overall and African descent populations. Hence, the present study aimsto estimate the prevalence of early-stage CKD and its associated risk factors in African-Brazilians from isolated African-descent communities. Herein, the detailed methodology design of the study is described. This population-based, prospective, longitudinal, cohort study (PREVRENAL) is performed in three stages: first, clinical, nutritional, and anthropometric evaluations; measurements of serum and urinary markers; and examinations of comorbiditieswere performed. Second, repeated examinations of individuals with CKD, systemic arterial hypertension, and/or diabetes mellitus; image screening; and cardiac risk assessment were performed. Third, long-term monitoring of all selected individuals will be conducted (ongoing). Using probability sampling, 1539 individuals from 32 communities were selected. CKD was defined asaglomerular filtration rate (GFR) ≤60 mL/min/1.73m 2 and albuminuria > 30 mg/day. This study proposes to identify and monitor individuals with and without reduced GFR and high albuminuria in isolated populations of African descendants in Brazil. As there are currently no specific recommendations for detecting CKD in African descendants, four equations for estimating the GFR based on serum creatinine and cystatin C were used and will be retrospectively compared. The present report describes the characteristics of the target population, selection of individuals, and detection of a population at risk, along with the imaging, clinical, and laboratory methodologies used. The first and second stages have been concluded and the results will be published in the near future. The subsequent (third) stage is the long-term, continuous monitoring of individuals diagnosed with renal abnormalities or with CKD risk factors. The entire study population will be re-evaluated five years after the study initiation. The expectation is to obtain information about CKD evolution among this population, including the progression rate, complication development, and cardiovascular events.

Body density affects stroke patterns in Baikal seals.

PubMed

Watanabe, Yuuki; Baranov, Eugene A; Sato, Katsufumi; Naito, Yasuhiko; Miyazaki, Nobuyuki

2006-09-01

Buoyancy is one of the primary external forces acting on air-breathing divers and it can affect their swimming energetics. Because the body composition of marine mammals (i.e. the relative amounts of lower-density lipid and higher-density lean tissue) varies individually and seasonally, their buoyancy also fluctuates widely, and individuals would be expected to adjust their stroke patterns during dives accordingly. To test this prediction, we attached acceleration data loggers to four free-ranging Baikal seals Phoca sibirica in Lake Baikal and monitored flipper stroking activity as well as swimming speed, depth and inclination of the body axis (pitch). In addition to the logger, one seal (Individual 4) was equipped with a lead weight that was jettisoned after a predetermined time period so that we had a set of observations on the same individual with different body densities. These four data sets revealed the general diving patterns of Baikal seals and also provided direct insights into the influence of buoyancy on these patterns. Seals repeatedly performed dives of a mean duration of 7.0 min (max. 15.4 min), interrupted by a mean surface duration of 1.2 min. Dive depths were 66 m on average, but varied substantially, with a maximum depth of 324 m. The seals showed different stroke patterns among individuals; some seals stroked at lower rates during descent than ascent, while the others had higher stroke rates during descent than ascent. When the lead weight was detached from Individual 4, the seal increased its stroke rate in descent by shifting swimming mode from prolonged glides to more stroke-and-glide swimming, and decreased its stroke rate in ascent by shifting from continuous stroking to stroke-and-glide swimming. We conclude that seals adopt different stroke patterns according to their individual buoyancies. We also demonstrate that the terminal speed reached by Individual 4 during prolonged glide in descent depended on its total buoyancy and pitch, with higher speeds reached in the weighted condition and at steeper pitch. A simple physical model allowed us to estimate the body density of the seal from the speed and pitch (1,027-1,046 kg m(-3), roughly corresponding to 32-41% lipid content, for the weighted condition; 1,014-1,022 kg m(-3), 43-47% lipid content, for the unweighted condition).

Locating single-point sources from arrival times containing large picking errors (LPEs): the virtual field optimization method (VFOM)

NASA Astrophysics Data System (ADS)

Li, Xi-Bing; Wang, Ze-Wei; Dong, Long-Jun

2016-01-01

Microseismic monitoring systems using local location techniques tend to be timely, automatic and stable. One basic requirement of these systems is the automatic picking of arrival times. However, arrival times generated by automated techniques always contain large picking errors (LPEs), which may make the location solution unreliable and cause the integrated system to be unstable. To overcome the LPE issue, we propose the virtual field optimization method (VFOM) for locating single-point sources. In contrast to existing approaches, the VFOM optimizes a continuous and virtually established objective function to search the space for the common intersection of the hyperboloids, which is determined by sensor pairs other than the least residual between the model-calculated and measured arrivals. The results of numerical examples and in-site blasts show that the VFOM can obtain more precise and stable solutions than traditional methods when the input data contain LPEs. Furthermore, we discuss the impact of LPEs on objective functions to determine the LPE-tolerant mechanism, velocity sensitivity and stopping criteria of the VFOM. The proposed method is also capable of locating acoustic sources using passive techniques such as passive sonar detection and acoustic emission.

An implantable instrument for studying the long-term flight biology of migratory birds

NASA Astrophysics Data System (ADS)

Spivey, Robin J.; Bishop, Charles M.

2014-01-01

The design of an instrument deployed in a project studying the high altitude Himalayan migrations of bar-headed geese (Anser indicus) is described. The electronics of this archival datalogger measured 22 × 14 × 6.5 mm, weighed 3 g, was powered by a ½AA-sized battery weighing 10 g and housed in a transparent biocompatible tube sealed with titanium electrodes for electrocardiography (ECG). The combined weight of 32 g represented less than 2% of the typical bodyweight of the geese. The primary tasks of the instrument were to continuously record a digitised ECG signal for heart-rate determination and store 12-bit triaxial accelerations sampled at 100 Hz with 15% coverage over each 2 min period. Measurement of atmospheric pressure provided an indication of altitude and rate of ascent or descent during flight. Geomagnetic field readings allowed for latitude estimation. These parameters were logged twice per minute along with body temperature. Data were stored to a memory card of 8 GB capacity. Instruments were implanted in geese captured on Mongolian lakes during the breeding season when the birds are temporarily flightless due to moulting. The goal was to collect data over a ten month period, covering both southward and northward migrations. This imposed extreme constraints on the design's power consumption. Raw ECG can be post-processed to obtain heart-rate, allowing improved rejection of signal interference due to strenuous activity of locomotory muscles during flight. Accelerometry can be used to monitor wing-beat frequency and body kinematics, and since the geese continued to flap their wings continuously even during rather steep descents, act as a proxy for biomechanical power. The instrument enables detailed investigation of the challenges faced by the geese during these arduous migrations which typically involve flying at extreme altitudes through cold, low density air where oxygen availability is significantly reduced compared to sea level.

Field evaluation of descent advisor trajectory prediction accuracy

DOT National Transportation Integrated Search

1996-07-01

The Descent Advisor (DA) automation tool has undergone a series of field tests : at the Denver Air Route Traffic Control Center to study the feasibility of : DA-based clearances and procedures. The latest evaluation, conducted in the : fall of 1995, ...

Entry, Descent and Landing Systems Analysis: Exploration Class Simulation Overview and Results

NASA Technical Reports Server (NTRS)

DwyerCianciolo, Alicia M.; Davis, Jody L.; Shidner, Jeremy D.; Powell, Richard W.

2010-01-01

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and exploration or human-scale missions. The year one exploration class mission activity considered technologies capable of delivering a 40-mt payload. This paper provides an overview of the exploration class mission study, including technologies considered, models developed and initial simulation results from the EDL-SA year one effort.

Error measure comparison of currently employed dose-modulation schemes for e-beam proximity effect control

NASA Astrophysics Data System (ADS)

Peckerar, Martin C.; Marrian, Christie R.

1995-05-01

Standard matrix inversion methods of e-beam proximity correction are compared with a variety of pseudoinverse approaches based on gradient descent. It is shown that the gradient descent methods can be modified using 'regularizers' (terms added to the cost function minimized during gradient descent). This modification solves the 'negative dose' problem in a mathematically sound way. Different techniques are contrasted using a weighted error measure approach. It is shown that the regularization approach leads to the highest quality images. In some cases, ignoring negative doses yields results which are worse than employing an uncorrected dose file.

Flight Data Entry, Descent, and Landing (EDL) Repository

NASA Technical Reports Server (NTRS)

Martinez, Elmain M.; Winterhalter, Daniel

2012-01-01

Dr. Daniel Winterhalter, NASA Engineering and Safety Center Chief Engineer at the Jet Propulsion Laboratory, requested the NASA Engineering and Safety Center sponsor a 3-year effort to collect entry, descent, and landing material and to establish a NASA-wide archive to serve the material. The principle focus of this task was to identify entry, descent, and landing repository material that was at risk of being permanently lost due to damage, decay, and undocumented storage. To provide NASA-wide access to this material, a web-based digital archive was created. This document contains the outcome of the effort.

Rosetta Mission's "7 Hours of Terror" and Philae's Descent

NASA Astrophysics Data System (ADS)

Blanco, Philip

2015-09-01

In November 2014 the Rosetta mission to Comet 67P/Churyumov-Gerasimenko made the headlines when its Philae lander completed a successful unpowered descent onto the surface of the comet nucleus after "7 hours of terror" for the mission scientists. 67P's irregular shape and rotation made this task even more challenging. Philae fell almost radially towards 67P, as shown in an animation produced by the European Space Agency (ESA) prior to the event. Below, we investigate whether it is possible to model the spacecraft's descent time and impact speed using concepts taught in an introductory physics course.

Prevalence of Hb S (HHB: c.20A > T) in a Honduran population of African descent.

PubMed

Erazo, Brian M; Ramírez, Gilberto A; Cerrato, Linda E; Pinto, Luis J; Castro, Edder J; Yanez, Néstor J; Montoya, Brayan; Fontecha, Gustavo A

2015-01-01

Sickle cell disease is the most common hemoglobinopathy worldwide, particularly in Africa and among people of African descent. Serious clinical consequences characterize the homozygous condition. To determine the prevalence of Hb S (HBB: c.20A > T) and anemia in a community of people of African descent from Honduras, 202 individuals were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The high prevalence found indicates that it is necessary to implement a program to prevent the consequences of this disease in vulnerable populations of Honduras.

Forward stair descent with hybrid neuroprosthesis after paralysis: Single case study demonstrating feasibility

PubMed Central

Bulea, Thomas C.; Kobetic, Rudi; Audu, Musa L.; Schnellenberger, John R.; Pinault, Gilles; Triolo, Ronald J.

2015-01-01

The ability to negotiate stairs is important for community access and independent mobility but requires more effort and strength than level walking. For this reason, previous attempts to utilize functional neuromuscular stimulation (FNS) to restore stair navigation after spinal cord injury (SCI) have had limited success and are not readily generalizable. Stair descent is particularly challenging because it requires energy absorption via eccentric muscle contractions, a task not easily accomplished with FNS. This article presents the design and initial testing of a hybrid neuroprosthesis with a variable impedance knee mechanism (VIKM-HNP) for stair descent. Using a 16-channel percutaneous FNS system, a muscle activation pattern was synthesized to descend stairs with the VIKM-HNP in a step-by-step fashion. A finite state control system was implemented to deactivate knee extensor stimulation and utilize the VIKM-HNP to absorb energy and regulate descent speed. Feasibility testing was performed on one individual with complete thoracic-level SCI. Stair descent was achieved with maximum upper-limb forces of less than 45% body weight compared with previously reported value of 70% with FNS only. The experiments also provided insight into design requirements for future hybrid systems for stair navigation, the implications of which are discussed. PMID:25437932

TDRS-M Spacecraft Arrival

NASA Image and Video Library

2017-06-23

NASA's TDRS-M satellite arrives inside its shipping container at Space Coast Regional Airport in Titusville, Florida, aboard a U.S. Air Force transport aircraft. The spacecraft is transported to the nearby Astrotech facility, also in Titusville, for preflight processing. The TDRS-M is the latest spacecraft destined for the agency's constellation of communications satellites that allows nearly continuous contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. Liftoff atop a United Launch Alliance Atlas V rocket is scheduled to take place from Space Launch Complex 41 at Cape Canaveral Air Force Station at 9:02 a.m. EDT Aug. 3, 2017.

TDRS-M Atlas V First and Second Stage Arrival

NASA Image and Video Library

2017-06-26

The United Launch Alliance (ULA) Mariner arrives at Port Canaveral in Florida carrying an Atlas V rocket booster bound for nearby Cape Canaveral Air Force Station. The rocket is scheduled to launch the Tracking and Data Relay Satellite, TDRS-M. It will be the latest spacecraft destined for the agency's constellation of communications satellites that allows nearly continuous contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. Liftoff atop the ULA Atlas V rocket is scheduled to take place from Cape Canaveral's Space Launch Complex 41 on Aug. 3, 2017 at 9:02 a.m. EDT.

Optimal Terminal Descent Guidance Logic to Achieve a Soft Lunar Touchdown

NASA Technical Reports Server (NTRS)

Lee, Allan Y.

2011-01-01

Altair Lunar Lander is the linchpin in the Constellation Program for human return to the Moon. In the 2010design reference mission, Altair is to be delivered to low Earth orbit by the Ares V heavy lift launch vehicle, and after subsequent docking with Orion in LEO, the Altair/Orion stack is delivered through trans-lunar injection (TLI). The Altair/Orion stack separates from the Ares V Earth departure stage shortly after TLI and continues the flight to the Moon as a single stack. Fig. 1 depicts one version of the Altair lunar lander.

Interpretation of 3He variations in the solar wind

NASA Technical Reports Server (NTRS)

Coplan, M. A.; Ogilvie, K. W.; Geiss, J.; Bochsler, P.

1983-01-01

The ion composition instrument (ICI) on ISEE-3 observed the isotopes of helium of mass 3 and 4 in the solar wind almost continuously between August 1978 and July 1982. This period included the increase towards the maximum of solar activity cycle 21, the maximum period, and the beginning of the descent towards solar minimum. Observations were made when the solar wind speed was between 300 and 620 km/s. For part of the period evidence for regular interplanetary magnetic sector structure was clear and a number of 3He flares occurred during this time.

Interpretation of He-3 abundance variations in the solar wind

NASA Technical Reports Server (NTRS)

Coplan, M. A.; Ogilvie, K. W.; Bochsler, P.; Geiss, J.

1984-01-01

The ion composition instrument (ICI) on ISEE-3 observed the isotopes of helium of mass 3 and 4 in the solar wind almost continuously between August 1978 and July 1982. This period included the increase towards the maximum of solar activity cycle 21, the maximum period, and the beginning of the descent towards solar minimum. Observations were made when the solar wind speed was between 300 and 620 km/s. For part of the period evidence for regular interplanetary magnetic sector structure was clear and a number of He-3 flares occurred during this time.

The Internet: Creating Equity through Continuous Education or Perpetuating a Digital Divide? Essay Review of "Race in Cyberspace," edited by Beth E. Kolko, Lisa Nakamura, and Gilbert B. Rodman; "The Internet: An Ethnographic Approach," by Daniel Miller and Don Slater; and "The Digital Divide: Standing at the Intersection of Race and Technology," by Raneta L. Mack.

ERIC Educational Resources Information Center

Lindsay, Beverly; Poindexter, Maria T.

2003-01-01

Reviews three books that address the relations between technology, race, and education, and illuminate the realistic impact that the Internet has had on persons of African descent in the United States and Trinidad. Discusses the digital divide among U.S. racial/ethnic groups and across countries and the social and political implications of the…

Characteristics of atmospheric transport into the Antarctic troposphere

NASA Astrophysics Data System (ADS)

Stohl, A.; Sodemann, H.

2010-01-01

We have developed a 5.5 year climatology of atmospheric transport into the Antarctic troposphere, which uses the same data set and methods as described in a recent study for the Arctic. This allows direct comparisons of transport properties for the two polar regions. The climatology is based on a simulation with the Lagrangian particle dispersion model FLEXPART, where the model atmosphere was globally filled with particles. Transport characteristics as well as emission sensitivities were derived from 6 hourly particle positions. We found that the probability for near-surface air to originate from the stratosphere on a time scale of 10 days is an order of magnitude higher near the South Pole than near the North Pole, a result of higher topography and descent that partly compensates for the flow of air down the Antarctic Plateau with the katabatic winds. The stratospheric influence is largest in fall, which is opposite to the seasonality in the Arctic. Stratospheric influence is much smaller over the shelf ice regions and in a band around Antarctica. The average time for which air near the surface has been exposed to continuous darkness in July (continuous light in January) is longest over the Ronne Ice Shelf and Ross Ice Shelf at ˜11 days (20 days). We calculated how sensitive Antarctic air masses are to emission input up to 30 days before arriving in Antarctica if removal processes are ignored. The emission sensitivity shows strong meridional gradients and, as a result, is generally low over South America, Africa, and Australia. For a 10 day time scale, the largest emission sensitivities over these continents are 1-2 orders of magnitude smaller than over Eurasia for transport to the Arctic, showing that foreign continents have a much smaller potential to pollute the Antarctic than the Arctic troposphere. Emission sensitivities and derived black carbon (BC) source contributions over South America, Africa, and Australia are substantially (a factor 10 for Africa) larger in winter than in summer. In winter, biomass burning contributes more BC than anthropogenic sources. For typical aerosol lifetimes of 5-10 days, ship emissions south of 60°S account for half of the total BC concentrations in the lowest 1000 m of the atmosphere south of 70°S in December. The increasing number of tourists visiting Antarctica and fishing vessels operating close to Antarctica are, therefore, a matter of concern.

Method and apparatus for producing a thermal atomic oxygen beam

NASA Technical Reports Server (NTRS)

Banks, Bruce A. (Inventor); Rutledge, Sharon K. (Inventor)

1994-01-01

Atomic oxygen atoms are routed to a material through a sufficiently tortuous path so that vacuum ultraviolet radiation is obstructed from arriving at the surface of the material. However, the material surface continues to be exposed to the atomic oxygen.

A Geometric Perspective on the Method of Descent

NASA Astrophysics Data System (ADS)

Wang, Qian

2018-06-01

We derive a first order representation formula for the tensorial wave equation \\Box_g φ^I=F^I in globally hyperbolic Lorentzian spacetimes {(M^{2+1}, g) by giving a geometric formulation of the method of descent which is applicable for any dimension.

JPL Tech Works Mars 2020 Descent Stage

NASA Image and Video Library

2018-03-13

A technician works on the descent stage for NASA's Mars 2020 mission inside JPL's Spacecraft Assembly Facility. Mars 2020 is slated to carry NASA's next Mars rover to the Red Planet in July of 2020. https://photojournal.jpl.nasa.gov/catalog/PIA22342

Accurate seismic phase identification and arrival time picking of glacial icequakes

NASA Astrophysics Data System (ADS)

Jones, G. A.; Doyle, S. H.; Dow, C.; Kulessa, B.; Hubbard, A.

2010-12-01

A catastrophic lake drainage event was monitored continuously using an array of 6, 4.5 Hz 3 component geophones in the Russell Glacier catchment, Western Greenland. Many thousands of events and arrival time phases (e.g., P- or S-wave) were recorded, often with events occurring simultaneously but at different locations. In addition, different styles of seismic events were identified from 'classical' tectonic earthquakes to tremors usually observed in volcanic regions. The presence of such a diverse and large dataset provides insight into the complex system of lake drainage. One of the most fundamental steps in seismology is the accurate identification of a seismic event and its associated arrival times. However, the collection of such a large and complex dataset makes the manual identification of a seismic event and picking of the arrival time phases time consuming with variable results. To overcome the issues of consistency and manpower, a number of different methods have been developed including short-term and long-term averages, spectrograms, wavelets, polarisation analyses, higher order statistics and auto-regressive techniques. Here we propose an automated procedure which establishes the phase type and accurately determines the arrival times. The procedure combines a number of different automated methods to achieve this, and is applied to the recently acquired lake drainage data. Accurate identification of events and their arrival time phases are the first steps in gaining a greater understanding of the extent of the deformation and the mechanism of such drainage events. A good knowledge of the propagation pathway of lake drainage meltwater through a glacier will have significant consequences for interpretation of glacial and ice sheet dynamics.

Wavelet-based automatic determination of the P- and S-wave arrivals

NASA Astrophysics Data System (ADS)

Bogiatzis, P.; Ishii, M.

2013-12-01

The detection of P- and S-wave arrivals is important for a variety of seismological applications including earthquake detection and characterization, and seismic tomography problems such as imaging of hydrocarbon reservoirs. For many years, dedicated human-analysts manually selected the arrival times of P and S waves. However, with the rapid expansion of seismic instrumentation, automatic techniques that can process a large number of seismic traces are becoming essential in tomographic applications, and for earthquake early-warning systems. In this work, we present a pair of algorithms for efficient picking of P and S onset times. The algorithms are based on the continuous wavelet transform of the seismic waveform that allows examination of a signal in both time and frequency domains. Unlike Fourier transform, the basis functions are localized in time and frequency, therefore, wavelet decomposition is suitable for analysis of non-stationary signals. For detecting the P-wave arrival, the wavelet coefficients are calculated using the vertical component of the seismogram, and the onset time of the wave is identified. In the case of the S-wave arrival, we take advantage of the polarization of the shear waves, and cross-examine the wavelet coefficients from the two horizontal components. In addition to the onset times, the automatic picking program provides estimates of uncertainty, which are important for subsequent applications. The algorithms are tested with synthetic data that are generated to include sudden changes in amplitude, frequency, and phase. The performance of the wavelet approach is further evaluated using real data by comparing the automatic picks with manual picks. Our results suggest that the proposed algorithms provide robust measurements that are comparable to manual picks for both P- and S-wave arrivals.

Urban sprawl and delayed ambulance arrival in the U.S.

PubMed

Trowbridge, Matthew J; Gurka, Matthew J; O'Connor, Robert E

2009-11-01

Minimizing emergency medical service (EMS) response time is a central objective of prehospital care, yet the potential influence of built environment features such as urban sprawl on EMS system performance is often not considered. This study measures the association between urban sprawl and EMS response time to test the hypothesis that features of sprawling development increase the probability of delayed ambulance arrival. In 2008, EMS response times for 43,424 motor-vehicle crashes were obtained from the Fatal Analysis Reporting System, a national census of crashes involving > or =1 fatality. Sprawl at each crash location was measured using a continuous county-level index previously developed by Ewing et al. The association between sprawl and the probability of a delayed ambulance arrival (> or =8 minutes) was then measured using generalized linear mixed modeling to account for correlation among crashes from the same county. Urban sprawl is significantly associated with increased EMS response time and a higher probability of delayed ambulance arrival (p=0.03). This probability increases quadratically as the severity of sprawl increases while controlling for nighttime crash occurrence, road conditions, and presence of construction. For example, in sprawling counties (e.g., Fayette County GA), the probability of a delayed ambulance arrival for daytime crashes in dry conditions without construction was 69% (95% CI=66%, 72%) compared with 31% (95% CI=28%, 35%) in counties with prominent smart-growth characteristics (e.g., Delaware County PA). Urban sprawl is significantly associated with increased EMS response time and a higher probability of delayed ambulance arrival following motor-vehicle crashes in the U.S. The results of this study suggest that promotion of community design and development that follows smart-growth principles and regulates urban sprawl may improve EMS performance and reliability.

A theory for the radiation of magnetohydrodynamic surface waves and body waves into the solar corona

NASA Technical Reports Server (NTRS)

Davila, Joseph M.

1988-01-01

The Green's function for the slab coronal hole is obtained explicitly. The Fourier integral representation for the radiated field inside and outside the coronal hole waveguide is obtained. The radiated field outside the coronal hole is calculated using the method of steepest descents. It is shown that the radiated field can be written as the sum of two contributions: (1) a contribution from the integral along the steepest descent path and (2) a contribution from all the poles of the integrand between the path of the original integral and the steepest descent path. The free oscillations of the waveguide can be associated with the pole contributions in the steepest descent representation for the Green's function. These pole contributions are essentially generalized surface waves with a maximum amplitude near the interface which separates the plasma inside the coronal hole from the surrounding background corona. The path contribution to the integral is essentially the power radiated in body waves.

Preliminary assessment of the Mars Science Laboratory entry, descent, and landing simulation

NASA Astrophysics Data System (ADS)

Way, David W.

On August 5, 2012, the Mars Science Laboratory rover, Curiosity, successfully landed inside Gale Crater. This landing was the seventh successful landing and fourth rover to be delivered to Mars. Weighing nearly one metric ton, Curiosity is the largest and most complex rover ever sent to investigate another planet. Safely landing such a large payload required an innovative Entry, Descent, and Landing system, which included the first guided entry at Mars, the largest supersonic parachute ever flown at Mars, and the novel Sky Crane landing system. A complete, end-to-end, six degree-of-freedom, multi-body computer simulation of the Mars Science Laboratory Entry, Descent, and Landing sequence was developed at the NASA Langley Research Center. In-flight data gathered during the successful landing is compared to pre-flight statistical distributions, predicted by the simulation. These comparisons provide insight into both the accuracy of the simulation and the overall performance of the Entry, Descent, and Landing system.

Comparison of linear cephalometric dimensions in Americans of European descent (Ann Arbor, Cleveland, Philadelphia) and Americans of African descent (Nashville).

PubMed

Dibbets, Jos M H; Nolte, Kai

2002-08-01

Eleven dimensions, extracted from four commercially available cephalometric atlases were compared. Three populations were American of European descent and one was American of African descent. The source data were carefully corrected for linear enlargement. The confounding effect of linear radiographic enlargement is exemplified by depicting the often-used distance, sella-nasion, before and after correction. Total face height was smallest in the Cleveland population and largest in the Nashville population. The difference was fully accounted for by differences in lower face height and that was the most variable of all dimensions studied. Upper face height was almost identical in all four populations. Posterior face height was largest in the Nashville population. The mandible in the Nashville population had an average ramus height, but a longer corpus. Mandibular dimensions were equal in the three other populations. The maxilla was clearly shortest in the Cleveland population and almost of equal length in the three others.

Free Falling in Stratified Fluids

NASA Astrophysics Data System (ADS)

Lam, Try; Vincent, Lionel; Kanso, Eva

2017-11-01

Leaves falling in air and discs falling in water are examples of unsteady descents due to complex interaction between gravitational and aerodynamic forces. Understanding these descent modes is relevant to many branches of engineering and science such as estimating the behavior of re-entry space vehicles to studying biomechanics of seed dispersion. For regularly shaped objects falling in homogenous fluids, the motion is relatively well understood. However, less is known about how density stratification of the fluid medium affects the falling behavior. Here, we experimentally investigate the descent of discs in both pure water and in stable linearly stratified fluids for Froude numbers Fr 1 and Reynolds numbers Re between 1000 -2000. We found that stable stratification (1) enhances the radial dispersion of the disc at landing, (2) increases the descent time, (3) decreases the inclination (or nutation) angle, and (4) decreases the fluttering amplitude while falling. We conclude by commenting on how the corresponding information can be used as a predictive model for objects free falling in stratified fluids.

Dopaminergic influence on rat tongue function and limb movement initiation.

PubMed

Ciucci, Michelle Renee; Connor, Nadine P

2009-04-01

Altering dopamine synaptic transmission can affect both cranial and limb sensorimotor function, but often to a different degree of severity. We hypothesized that haloperidol has dose-dependent but differential effects on lingual forces, lingual movement rates, and limb movement initiation. We measured average and maximal lingual force, tongue press rate and cataleptic descent time in nine Fischer 344/Brown Norway rats in varied doses of haloperidol. Decreases in lingual force and temporal parameters and increases in cataleptic descent time were related to haloperidol dose. However, they were related to a different degree as the relationships were strong between average force and tongue press rate, moderate between maximal force and tongue press rate, moderate between average force and cataleptic descent time, and weak between maximal force and cataleptic descent time. Elucidating the relationships between the cranial and limb sensorimotor systems in the context of altered dopamine synaptic transmission may assist in developing therapies for conditions such as Parkinson's disease.

Involvement of Fibroblast Growth Factors and Their Receptors in Epididymo-Testicular Descent and Maldescent

PubMed Central

Hadziselimovic, Faruk

2016-01-01

Maldescent of the epididymo-testicular unit can occur as an isolated event or as a component of various syndromes. When part of a syndrome, crypto-epididymis is usually accompanied by other genital and/or extragenital features. Epididymis development is primarily regulated by androgens, and successful epididymo-testicular unit development and descent requires an intact hypothalamic-pituitary-gonadal axis. The developing gonadotropin-releasing hormone system is essential for epididymo-testicular descent and is highly sensitive to reduced fibroblast growth factor (FGF) signaling. Our understanding of the impact of FGFR1 in the process of epididymo-testicular descent has recently improved. At later stages of embryonic development, the undifferentiated epididymal mesenchyme is a specific domain for FGFR1 expression. The majority of individuals with syndromic crypto-epididymis, as well as individuals with isolated maldescent of the epididymo-testicular unit, exhibit some disturbance of FGF, FGFR1 and/or genes involved in hypothalamic-pituitary-gonadal axis regulation. However, the mechanisms underlying FGF dysregulation may differ between various syndromes. PMID:27022326

Involvement of Fibroblast Growth Factors and Their Receptors in Epididymo-Testicular Descent and Maldescent.

PubMed

Hadziselimovic, Faruk

2016-02-01

Maldescent of the epididymo-testicular unit can occur as an isolated event or as a component of various syndromes. When part of a syndrome, crypto-epididymis is usually accompanied by other genital and/or extragenital features. Epididymis development is primarily regulated by androgens, and successful epididymo-testicular unit development and descent requires an intact hypothalamic-pituitary-gonadal axis. The developing gonadotropin-releasing hormone system is essential for epididymo-testicular descent and is highly sensitive to reduced fibroblast growth factor (FGF) signaling. Our understanding of the impact of FGFR1 in the process of epididymo-testicular descent has recently improved. At later stages of embryonic development, the undifferentiated epididymal mesenchyme is a specific domain for FGFR1 expression. The majority of individuals with syndromic crypto-epididymis, as well as individuals with isolated maldescent of the epididymo-testicular unit, exhibit some disturbance of FGF, FGFR1 and/or genes involved in hypothalamic-pituitary-gonadal axis regulation. However, the mechanisms underlying FGF dysregulation may differ between various syndromes.

Effect of shoe type on descending a curb.

PubMed

George, Juff; Heller, Michelle; Kuzel, Michael

2012-01-01

The aim of this study was to evaluate the effect of shoe type on the performance of women during curb descent. Performance during curb stepping may be explained by biomechanical research that has evaluated the kinematics of overground walking and stair ascent and descent. Studies have reported that women exhibit performance differences when wearing high heels, flip flops and sneakers during overground walking and stair ascent and descent. Thus, in addition to features of the curb, the type of shoe being worn may also affect performance. Although several studies have investigated curb stepping, no known studies have investigated the effects of different types of footwear on curb descent performance. This research was conducted in a real-world environment where participants wore three different types of shoes and performed a series of activities that involved curb stepping. The subjects were videotaped while descending a curb, allowing for observation of changes in gait parameters. Results of this study indicate that wearing high heels leads to performance differences as compared to wearing flip flops or sneakers.

Hazard avoidance via descent images for safe landing

NASA Astrophysics Data System (ADS)

Yan, Ruicheng; Cao, Zhiguo; Zhu, Lei; Fang, Zhiwen

2013-10-01

In planetary or lunar landing missions, hazard avoidance is critical for landing safety. Therefore, it is very important to correctly detect hazards and effectively find a safe landing area during the last stage of descent. In this paper, we propose a passive sensing based HDA (hazard detection and avoidance) approach via descent images to lower the landing risk. In hazard detection stage, a statistical probability model on the basis of the hazard similarity is adopted to evaluate the image and detect hazardous areas, so that a binary hazard image can be generated. Afterwards, a safety coefficient, which jointly utilized the proportion of hazards in the local region and the inside hazard distribution, is proposed to find potential regions with less hazards in the binary hazard image. By using the safety coefficient in a coarse-to-fine procedure and combining it with the local ISD (intensity standard deviation) measure, the safe landing area is determined. The algorithm is evaluated and verified with many simulated descent downward looking images rendered from lunar orbital satellite images.

The relief formed by the descent phenomenon in the north-east part of Kosova.

PubMed

Bulliqi, Shpejtim; Isufi, Florim; Ramadani, Ibrahim; Gashi, Gani

2012-04-01

In the diverse relief of north-east part of Kosova a relatively wide range occupies the relief modelled by the descent phenomenon, which is conditioned by morph-structural and climatic factors quite suitable for their development. The morphogenesis activity of descent phenomenon is conditioned by the types of rocks, tectonic process of this region and climatic conditions. These factors condition horizontal and vertical relief fragmentation, slope, especially in Gollaku mountains and in SE part of Kopaonik mountain. Along the tectonic descents, the steepness is detaching and the detaching lines consisting of magmatic rocks show overthrows, demolitions and stony torrents, but the Teri gene composition formations are modelled by sliding and muddy torrents, depending upon the presence of clayey and alevrolite belts on these Teri gene ones. The impact of factors and conditions on the relief of this part, the phenomena like demolitions, overthrows, sliding, muddy torrents, stony torrents, etc, operate here, which play an important morphological role in the modelling of relief.

Use of Data Comm by Flight Crew to Conduct Interval Management Operations to Parallel Dependent Runways

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Hubbs, Clay; Shay, Rick; Karanian, James

2011-01-01

The Interval Management (IM) concept is being developed as a method to maintain or increase high traffic density airport arrival throughput while allowing aircraft to conduct near idle thrust descents. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR1) experiment at NASA Langley Research Center used 24 commercial pilots to examine IM procedures to conduct parallel dependent runway arrival operations while maintaining safe but efficient intervals behind the preceding aircraft. The use of IM procedures during these operations requires a lengthy and complex clearance from Air Traffic Control (ATC) to the participating aircraft, thereby making the use of Controller Pilot Data Link Communications (CPDLC) highly desirable as the communication method. The use of CPDLC reduces the need for voice transmissions between controllers and flight crew, and enables automated transfer of IM clearance elements into flight management systems or other aircraft avionics. The result is reduced crew workload and an increase in the efficiency of crew procedures. This paper focuses on the subset of data collected related to the use of CPDLC for IM operations into a busy airport. Overall, the experiment and results were very successful, with the mean time under 43 seconds for the flight crew to load the clearance into the IM spacing tool, review the calculated speed, and respond to ATC. An overall mean rating of Moderately Agree was given when the crews were asked if the use of CPDLC was operationally acceptable as simulated in this experiment. Approximately half of the flight crew reported the use of CPDLC below 10,000 for IM operations was unacceptable, with 83% reporting below 5000 was unacceptable. Also described are proposed modifications to the IM operations that may reduce CPDLC Respond time to less than 30 seconds and should significantly reduce the complexity of crew procedures, as well as follow-on research issues for operational use of CPDLC during IM operations.

49 CFR 1005.5 - Disposition of claims.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... shall pay, decline, or make a firm compromise settlement offer in writing or electronically to the... to apply a depreciation factor to arrive at the current actual value of the lost or damaged item...

49 CFR 370.9 - Disposition of claims.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... delay to property transported shall pay, decline, or make a firm compromise settlement offer in writing... the lost or damaged item as a base to apply a depreciation factor to arrive at the current actual...

14 CFR 93.29 - International Arrival Authorizations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction... marketing arrangement unless the flight was predominately marketed, by contract, under the control of another Carrier. If the flight was under the marketing control of another Carrier or the entire inventory...

Early detection of invasive fishes in Lake Superior

EPA Science Inventory

Invasive species pose a serious threat to the Great Lakes warranting continual monitoring for the arrival of new species. Three locations in Lake Superior were identified as "high risk" for new introductions: St. Louis River near Duluth, MN, Upper St. Marys River near S...

The Ecology of Minority Languages in Melbourne

ERIC Educational Resources Information Center

Bradshaw, Julie

2013-01-01

Melbourne's linguistic and cultural diversity has continually changed in response to global economic forces and shifting patterns of war and conflict. Immigrant and refugee communities have arrived with different skills, educational and professional profiles, and cultural and religious values. The ecological niches of three contrasting linguistic…

Early detection of non-indigenous fishes in Lake Superior

EPA Science Inventory

Invasive species pose a serious threat to the ecological stability of the Great Lakes warranting continual monitoring for the arrival of new species. Three locations in Lake Superior were identified as “high risk” for new introductions: St. Louis River near Duluth, M...

Facing Up to Facebook

ERIC Educational Resources Information Center

Eberhardt, David M.

2007-01-01

While college educators have long recognized the intensely social quality of campus life, many faculty and administrators have watched student culture become even more social in recent years as various interactive technologies, including online social networks, have emerged. Starting before students arrive on campus and continuing into their days…

Cuff-less blood pressure measurement using pulse arrival time and a Kalman filter

NASA Astrophysics Data System (ADS)

Zhang, Qiang; Chen, Xianxiang; Fang, Zhen; Xue, Yongjiao; Zhan, Qingyuan; Yang, Ting; Xia, Shanhong

2017-02-01

The present study designs an algorithm to increase the accuracy of continuous blood pressure (BP) estimation. Pulse arrival time (PAT) has been widely used for continuous BP estimation. However, because of motion artifact and physiological activities, PAT-based methods are often troubled with low BP estimation accuracy. This paper used a signal quality modified Kalman filter to track blood pressure changes. A Kalman filter guarantees that BP estimation value is optimal in the sense of minimizing the mean square error. We propose a joint signal quality indice to adjust the measurement noise covariance, pushing the Kalman filter to weigh more heavily on measurements from cleaner data. Twenty 2 h physiological data segments selected from the MIMIC II database were used to evaluate the performance. Compared with straightforward use of the PAT-based linear regression model, the proposed model achieved higher measurement accuracy. Due to low computation complexity, the proposed algorithm can be easily transplanted into wearable sensor devices.

Luteinising hormone releasing hormone for incomplete descent of the testis.

PubMed

Klidjian, A M; Swift, P G; Johnstone, J M

1985-06-01

Forty boys with 54 incompletely descended testes took part in a double blind, controlled trial of intranasal luteinising hormone releasing hormone. In the control (placebo) group of 18 boys there was no significant change in testicular descent and all required orchidopexy; in the 22 treated boys, however, 12 of 29 testes (42%) were found in a lower position. This study supports the idea that a trial of intranasal luteinising hormone releasing hormone (1200 micrograms/day for 28 days) will help clarify the need for orchidopexy in at least 30% of boys with incomplete descent of the testis, particularly those in whom the testes have emerged from the inguinal canal.

Historical perspective - Viking Mars Lander propulsion

NASA Technical Reports Server (NTRS)

Morrisey, Donald C.

1989-01-01

This paper discusses the Viking 1 and 2 missions to Mars in 1975-1976 and describes the design evolution of the Viking Terminal Descent Rocket Engines responsible for decelerating the Viking Mars Landers during the final portion of their descent from orbit. The Viking Terminal Descent Rocket Engines have twice the thrust of the largest monopropellant hydrazine engine developed previously but weigh considerably less. The engine has 18 nozzles, the capability of 10:1 throttling, is totally sealed until fired, employs no organic unsealed materials, is 100 percent germ free, utilized hydrazine STM-20 as the propellant, and starts at a temperature more than 45 F below the propellant's freezing point.

Mars Smart Lander Simulations for Entry, Descent, and Landing

NASA Technical Reports Server (NTRS)

Striepe, S. A.; Way, D. W.; Balaram, J.

2002-01-01

Two primary simulations have been developed and are being updated for the Mars Smart Lander Entry, Descent, and Landing (EDL). The high fidelity engineering end-to-end EDL simulation that is based on NASA Langley's Program to Optimize Simulated Trajectories (POST) and the end-to-end real-time, hardware-in-the-loop simulation testbed, which is based on NASA JPL's (Jet Propulsion Laboratory) Dynamics Simulator for Entry, Descent and Surface landing (DSENDS). This paper presents the status of these Mars Smart Lander EDL end-to-end simulations at this time. Various models, capabilities, as well as validation and verification for these simulations are discussed.

Entry, Descent and Landing Systems Analysis Study: Phase 1 Report

NASA Technical Reports Server (NTRS)

DwyerCianciolo, Alicia M.; Davis, Jody L.; Komar, David R.; Munk, Michelle M.; Samareh, Jamshid A.; Powell, Richard W.; Shidner, Jeremy D.; Stanley, Douglas O.; Wilhite, Alan W.; Kinney, David J.;

Multi stage unreliable retrial Queueing system with Bernoulli vacation

NASA Astrophysics Data System (ADS)

Radha, J.; Indhira, K.; Chandrasekaran, V. M.

2017-11-01

In this work we considered the Bernoulli vacation in group arrival retrial queues with unreliable server. Here, a server providing service in k stages. Any arriving group of units finds the server free, one from the group entering the first stage of service and the rest are joining into the orbit. After completion of the i th, (i=1,2,…k) stage of service, the customer may go to (i+1)th stage with probability θi , or leave the system with probability qi = 1 - θi , (i = 1,2,…k - 1) and qi = 1, (i = k). The server may enjoy vacation (orbit is empty or not) with probability v after finishing the service or continuing the service with probability 1-v. After finishing the vacation, the server search for the customer in the orbit with probability θ or remains idle for new arrival with probability 1-θ. We analyzed the system using the method of supplementary variable.

Huygens Atmospheric Structure Instrument (HASI) test by a stratospheric balloon experiment

NASA Astrophysics Data System (ADS)

Fulchignoni, M.; Gaborit, V.; Aboudam, A.; Angrilli, F.; Antonello, M.; Bastianello, S.; Bettanini, C.; Bianchini, G.; Colombatti, G.; Ferri, F.; Lion Stoppato, P.

2002-09-01

We developped a series of balloon experiments parachuting a 1:1 scale mock up of the Huygens probe from an altitude larger than 30 km in order to simulate at planetary scale the final part of the descent of the probe in the Titan atmosphere. The Earth atmosphere represents a natural laboratory where most of the physical parameters meet quite well the bulk condition of Titan's environment, with the exception of temperature. A first balloon experiment has been carried out in June 2001 and the results have been reported at the last DPS (V. Gaborit et al., BAAS 33, 38.03) The mock up of the probe descending in the Titan atmosphere for the Huygens Cassini Mission has been successfully launched with stratospheric balloon from Italian Space Agency Base "Luigi Broglio" in Sicily and recovered on May 30th 2002. The probe has been lifted at 32 km altitude and then released to perform a 45 minutes descent decelerated by parachute, to simulate Huygens mission at Titan. Preliminary aerodynamics study of the probe has focused on the achievement of a descent velocity profile and a spin rate profile, satisfying the Huygens mission to Titan requirements. The descent velocity and spin rate have been calculated by solving a system of ODE describing the translational and rotational motion of the probe trough the earth atmosphere during parachute aided descent Results of these calculations have driven the choice of an appropriate angle of attack of the blades in the bottom of the probe and ballast weight during flight. The probe is hosting spares of HASI sensors, housekeeping sensors and other dedicated sensors, Beagle II UV Sensors and Huygens SSP Tilt Sensor, for a total of 77 acquired sensor channels, sampled during ascent, drift and descent phase. Main goals are i) to verify sensor performance and perform a realistic functional test in dynamical and environmental conditions similar to those during the descent in Titan atmosphere; ii) to investigate impact at ground to check the impact detection sequence of HASI accelerometer and HASI in the surface phase; iii) to test the codes developped to perfor the descent trajectory reconstruction of the Huygens probe in the Titan atmosphere. An integrated data acquisition and instrument control system has been developed, based on PC architecture and soft-real-time application. Sensors channels have been sampled at the nominal HASI data rates, with a max rate of 1 kHz. Software has been developed for data acquisition, onboard storage and telemetry transmission satisfying all requests for real-time monitoring, diagnostic and redundancy.

Navigation and EDL for the Mars Exploration Rovers

NASA Technical Reports Server (NTRS)

Watkins, Michael M.; Han, Dongsuk

2006-01-01

A viewgraph presentation on Deep Space Navigation, and Entry, Decent, and Landing (EDL) for Mars Exploration Rovers is shown. The contents include: 1) JPL Spacecraft Operating across the Solar System; 2) 2003 - 2004: The Busiest Period in JPL's History; 3) Deep Space Navigation Will Enable Many of the New NASA Missions; 4) What Exactly is Navigation vs. GNC for Deep Space?; 5) Cruise and Approach: Why is Deep Space Navigation So Difficult?; 6) Project Importance of GNC: Landing Site Selection; 7) Planetary Communications and Tracking; 8) Tracking Data Types; 9) Delta Differential One-Way Range (deltaDOR); 10) All Solutions Leading up to TCM-4 Design; 11) Entry Flight Path Sensitivities; 12) MER Navigation Results; 13) Atmospheric Entry Targeting and Delivery; 14) Landing Ellipse Orientation; 15) MER Landing Site Trade Example; 16) Entry, Descent and Landing: Entry Guidance or What Things Do We NOT do for MER Landings (but we will later...); 17) Entering Martian Space 8:29 p.m. PST (ERT); 18) Entry, Descent and Landing; 19) Entry, Descent and Landing: Terminal Guidance; 20) The Challenge Going from 12,000 mph to Zero in Less Than Six Minutes; 21) Spirit Landing Location; 22) Entry, Descent and Landing: The Future; 23) Powered Descent Time-Line; and 24) Updated Sky Crane Maneuver Description. A short summary is also given on planetary guidance, navigation and control as it pertains to EDL systems

Divergent mortality trends by ethnicity in Fiji.

PubMed

Taylor, Richard; Carter, Karen; Naidu, Shivnay; Linhart, Christine; Azim, Syed; Rao, Chalapati; Lopez, Alan D

2013-12-01

To examine trends in infant mortality rate (IMR), adult mortality and life expectancy (LE) in the two major Fijian ethnic groups since 1975. Estimates of IMR, adult mortality (15-59 years) and LE by ethnicity are calculated from previously unreported Fiji Ministry of Health data and extracted from published sources. Over 1975-2008: IMR decreased from 33 to 20 deaths/1,000 live births in i-Taukei (Fiji Melanesians); and 38 to 18 in Fijians of Indian descent. Increased adult male mortality among i-Taukei and decline among Fijians of Indian descent led to an equal probability of dying in 2007 of 29%; while in female adults the probability trended upwards in i-Taukei to 25%, and declined in Fijians of Indian descent to 17%. Life expectancy in both ethnicities increased until 1985 (to 64 years for males; 68 for females) then forming a plateau in males of both ethnicities, and Fijian females of Indian descent, but declining in i-Taukei females to 66 years in 2007. Despite IMR declines over 1975-2008, LE for i-Taukei and Fijians of Indian descent has not increased since 1985, and has actually decreased in i-Taukei women, consistent with trends in adult mortality (15-59 years). Mortality analyses in Fiji that consider the entire population mask divergent trends in the major ethnic groups. This situation is most likely a consequence of non-communicable disease mortality, requiring further assessment and a strengthened response.

High-Resolution Detection of Identity by Descent in Unrelated Individuals

PubMed Central

Browning, Sharon R.; Browning, Brian L.

2010-01-01

Detection of recent identity by descent (IBD) in population samples is important for population-based linkage mapping and for highly accurate genotype imputation and haplotype-phase inference. We present a method for detection of recent IBD in population samples. Our method accounts for linkage disequilibrium between SNPs to enable full use of high-density SNP data. We find that our method can detect segments of a length of 2 cM with moderate power and negligible false discovery rate in Illumina 550K data in Northwestern Europeans. We compare our method with GERMLINE and PLINK, and we show that our method has a level of resolution that is significantly better than these existing methods, thus extending the usefulness of recent IBD in analysis of high-density SNP data. We survey four genomic regions in a sample of UK individuals of European descent and find that on average, at a given location, our method detects IBD in 2.7 per 10,000 pairs of individuals in Illumina 550K data. We also present methodology and results for detection of homozygosity by descent (HBD) and survey the whole genome in a sample of 1373 UK individuals of European descent. We detect HBD in 4.7 individuals per 10,000 on average at a given location. Our methodology is implemented in the freely available BEAGLE software package. PMID:20303063

LANDER program manual: A lunar ascent and descent simulation

NASA Technical Reports Server (NTRS)

1988-01-01

LANDER is a computer program used to predict the trajectory and flight performance of a spacecraft ascending or descending between a low lunar orbit of 15 to 500 nautical miles (nm) and the lunar surface. It is a three degree-of-freedom simulation which is used to analyze the translational motion of the vehicle during descent. Attitude dynamics and rotational motion are not considered. The program can be used to simulate either an ascent from the Moon or a descent to the Moon. For an ascent, the spacecraft is initialized at the lunar surface and accelerates vertically away from the ground at full thrust. When the local velocity becomes 30 ft/s, the vehicle turns downrange with a pitch-over maneuver and proceeds to fly a gravity turn until Main Engine Cutoff (MECO). The spacecraft then coasts until it reaches the requested holding orbit where it performs an orbital insertion burn. During a descent simulation, the lander begins in the holding orbit and performs a deorbit burn. It then coasts to pericynthion, where it reignites its engines and begins a gravity turn descent. When the local horizontal velocity becomes zero, the lander pitches up to a vertical orientation and begins to hover in search of a landing site. The lander hovers for a period of time specified by the user, and then lands.

Patterns of vitamin D, parathyroid hormone and c-terminal telopeptide of collagen type 1 in Caucasian and African descent HIV-infected populations in Central Europe.

PubMed

Noe, Sebastian; Oldenbuettel, Celia; Heldwein, Silke; Jaeger, Hans; Wolf, Eva

2017-10-02

Risk factors for bone loss in HIV patients might differ or have a different impact in African descent compared to Caucasian populations. The aim of the paper is to analyze the relevance of risk factors on surrogate markers of bone metabolism in HIV-infected African descent and Caucasian patients. This is a cross-sectional study in a single HIV-specialized research and clinical care center in Munich, Germany. We included 889 patients in the study, among them 771 Caucasians (86.7%). Only in Caucasians lower vitamin D levels [OR: 2.5 (95CI: 1.6-3.7)], lower calcium levels [OR: 1.8 (1.2-2.8)], and the use of tenofovir disoproxil fumarate [OR: 2.8 (1.8-4.4)] were significantly associated with elevated PTH in multivariate analysis. Likewise, only in Caucasians elevated PTH was significantly associated with elevated markers of c-terminal telopeptides of collagen type 1 (β-CTX) [OR: 1.7 (1.0-3.0)]. Effects of traditional risk factors for secondary hyperparathyroidism and increased markers of bone turn-over seem to be less distinct in African descent HIV patients. The clinical impact and generalizability of this finding as well as the significance of vitamin D supplementation in African descent patients therefore warrants further investigation.

A Comparative Study of Probability Collectives Based Multi-agent Systems and Genetic Algorithms

NASA Technical Reports Server (NTRS)

Huang, Chien-Feng; Wolpert, David H.; Bieniawski, Stefan; Strauss, Charles E. M.

2005-01-01

We compare Genetic Algorithms (GA's) with Probability Collectives (PC), a new framework for distributed optimization and control. In contrast to GA's, PC-based methods do not update populations of solutions. Instead they update an explicitly parameterized probability distribution p over the space of solutions. That updating of p arises as the optimization of a functional of p. The functional is chosen so that any p that optimizes it should be p peaked about good solutions. The PC approach works in both continuous and discrete problems. It does not suffer from the resolution limitation of the finite bit length encoding of parameters into GA alleles. It also has deep connections with both game theory and statistical physics. We review the PC approach using its motivation as the information theoretic formulation of bounded rationality for multi-agent systems. It is then compared with GA's on a diverse set of problems. To handle high dimensional surfaces, in the PC method investigated here p is restricted to a product distribution. Each distribution in that product is controlled by a separate agent. The test functions were selected for their difficulty using either traditional gradient descent or genetic algorithms. On those functions the PC-based approach significantly outperforms traditional GA's in both rate of descent, trapping in false minima, and long term optimization.

Atrioventricular nonuniformity of pericardial constraint.

PubMed

Hamilton, Douglas R; Sas, Rozsa; Tyberg, John V

2004-10-01

Physiologists and clinicians commonly refer to "pressure" as a measure of the constraining effects of the pericardium; however, "pericardial pressure" is really a local measurement of epicardial radial stress. During diastole, from the bottom of the y descent to the beginning of the a wave, pericardial pressure over the right atrium (P(pRA)) is approximately equal to that over the right ventricle (P(pRV)). However, in systole, during the interval between the bottom of the x descent and the peak of the v wave, these two pericardial pressures appear to be completely decoupled in that P(pRV) decreases, whereas P(pRA) remains constant or increases. This decoupling indicates considerable mechanical independence between the RA and RV during systole. That is, RV systolic emptying lowers P(pRV), but P(pRA) continues to increase, suggesting that the relation of the pericardium to the RA must allow effective constraint, even though the pericardium over the RV is simultaneously slack. In conclusion, we measured the pericardial pressure responsible for the previously reported nonuniformity of pericardial strain. P(pRA) and P(pRV) are closely coupled during diastole, but during systole they become decoupled. Systolic nonuniformity of pericardial constraint may augment the atrioventricular valve-opening pressure gradient in early diastole and, so, affect ventricular filling.

Led to the Liberal Arts

ERIC Educational Resources Information Center

Roach, Ronald

2005-01-01

The individual stories of scholars of South Asian descent are as divergent as the communities, countries of origin and cultural traditions from which they and their families originate. Though their numbers are believed to trail those of their counterparts in business, science and engineering fields, U.S. scholars of South Asian descent are adding…

Familial primary cutaneous amyloidosis. Clinical, genetic, and immunofluorescent studies.

PubMed

Vasily, D B; Bhatia, S G; Uhlin, S R

1978-08-01

Familial primary cutaneous amyloidosis, a rare, autosomal dominant genodermatosis, affected 16 of 46 family members of German descent. Previous case reports involved families of Russian, Spanish, or Chinese descent. The finding of IgG, IgM, C3 in the amyloid deposits confirms recent reports of immunofluorescent dermal amyloid deposits.