Bayesian Inference in Satellite Gravity Inversion

NASA Technical Reports Server (NTRS)

Kis, K. I.; Taylor, Patrick T.; Wittmann, G.; Kim, Hyung Rae; Torony, B.; Mayer-Guerr, T.

2005-01-01

To solve a geophysical inverse problem means applying measurements to determine the parameters of the selected model. The inverse problem is formulated as the Bayesian inference. The Gaussian probability density functions are applied in the Bayes's equation. The CHAMP satellite gravity data are determined at the altitude of 400 kilometer altitude over the South part of the Pannonian basin. The model of interpretation is the right vertical cylinder. The parameters of the model are obtained from the minimum problem solved by the Simplex method.

Potential fields & satellite missions: what they tell us about the Earth's core?

NASA Astrophysics Data System (ADS)

Mandea, M.; Panet, I.; Lesur, V.; de Viron, O.; Diament, M.; Le Mouël, J.

2012-12-01

Since the advent of satellite potential field missions, the search to find information they can carry about the Earth's core has been motivated both by an interest in understanding the structure of dynamics of the Earth's interior and by the possibility of applying new space data analysis. While it is agreed upon that the magnetic field measurements from space bring interesting information on the rapid variations of the core magnetic field and flows associated with, the question turns to whether the core process can have a signature in the space gravity data. Here, we tackle this question, in the light of the recent data from the GRACE mission, that reach an unprecedented precision. Our study is based on eight years of high-resolution, high-accuracy gravity and magnetic satellite data, provided by the GRACE and CHAMP satellite missions. From the GRACE CNES/GRGS geoid solutions, we have emphasized the long-term variability by using a specific post-processing technique. From the CHAMP magnetic data we have computed models for the core magnetic field and its temporal variations, and the flow at the top of the core. A correlation analysis between the gravity and magnetic gridded series indicates that the inter-annual changes in the core magnetic field - under a region from the Atlantic to Indian Oceans - coincide with similar changes in the gravity field. These results should be considered as a constituent when planning new Earth's observation space missions and future innovations relevant to both gravity (after GRACE Follow-On) and magnetic (after Swarm) missions.

Atmospheric densities derived from CHAMP/STAR accelerometer observations

NASA Astrophysics Data System (ADS)

Bruinsma, S.; Tamagnan, D.; Biancale, R.

2004-03-01

The satellite CHAMP carries the accelerometer STAR in its payload and thanks to the GPS and SLR tracking systems accurate orbit positions can be computed. Total atmospheric density values can be retrieved from the STAR measurements, with an absolute uncertainty of 10-15%, under the condition that an accurate radiative force model, satellite macro-model, and STAR instrumental calibration parameters are applied, and that the upper-atmosphere winds are less than 150 m/ s. The STAR calibration parameters (i.e. a bias and a scale factor) of the tangential acceleration were accurately determined using an iterative method, which required the estimation of the gravity field coefficients in several iterations, the first result of which was the EIGEN-1S (Geophys. Res. Lett. 29 (14) (2002) 10.1029) gravity field solution. The procedure to derive atmospheric density values is as follows: (1) a reduced-dynamic CHAMP orbit is computed, the positions of which are used as pseudo-observations, for reference purposes; (2) a dynamic CHAMP orbit is fitted to the pseudo-observations using calibrated STAR measurements, which are saved in a data file containing all necessary information to derive density values; (3) the data file is used to compute density values at each orbit integration step, for which accurate terrestrial coordinates are available. This procedure was applied to 415 days of data over a total period of 21 months, yielding 1.2 million useful observations. The model predictions of DTM-2000 (EGS XXV General Assembly, Nice, France), DTM-94 (J. Geod. 72 (1998) 161) and MSIS-86 (J. Geophys. Res. 92 (1987) 4649) were evaluated by analysing the density ratios (i.e. "observed" to "computed" ratio) globally, and as functions of solar activity, geographical position and season. The global mean of the density ratios showed that the models underestimate density by 10-20%, with an rms of 16-20%. The binning as a function of local time revealed that the diurnal and semi-diurnal components are too strong in the DTM models, while all three models model the latitudinal gradient inaccurately. Using DTM-2000 as a priori, certain model coefficients were re-estimated using the STAR-derived densities, yielding the DTM-STAR test model. The mean and rms of the global density ratios of this preliminary model are 1.00 and 15%, respectively, while the tidal and latitudinal modelling errors become small. This test model is only representative of high solar activity conditions, while the seasonal effect is probably not estimated accurately due to correlation with the solar activity effect. At least one more year of data is required to separate the seasonal effect from the solar activity effect, and data taken under low solar activity conditions must also be assimilated to construct a model representative under all circumstances.

Levitation of water and organic substances in high static magnetic fields

NASA Astrophysics Data System (ADS)

Beaugnon, E.; Tournier, R.

1991-08-01

The levitation of various diamagnetic liquid and solid substances such as water, ethanol, acetone, bismuth, antimony, graphite, wood and plastic has been achieved at room temperature in a strong inhomogeneous static magnetic field. These experiments were performed in the hybrid magnet at the Service National des Champs Intenses (CNRS, Grenoble). These findings show that high field superconducting magnets could be used to provide a contactless, low gravity environment for the elaboration of a wide range of materials. En utilisant les forts champs magnétiques produits par la bobine hybride du Service National des Champs Intenses (CNRS, Grenoble), nous avons obtenu àtempérature ambiante la lévitation de substances diamagnétiques solides ou liquides telles que l'eau, l'alcool, l'acétone, le bismuth, l'antimoine, le graphite, le bois et le plastique. Ces résultats montrent que les bobines supraconductrices peuvent être utilisées pour l'élaboration de nombreux matériaux en gravité réduite, sans contact avec un contenant.

Simultaneous ground-satellite observations of daytime traveling ionospheric disturbances over Japan using the GPS-TEC network and the CHAMP satellite

NASA Astrophysics Data System (ADS)

Moral, A. C.; Shiokawa, K.; Otsuka, Y.; Liu, H.; Nishioka, M.; Tsugawa, T.

2017-12-01

We report results of simultaneous ground-satellite measurements of daytime travelling ionospheric disturbances (TIDs) over Japan by using the GEONET GPS receiver network and the CHAMP satellite. For the two years of 2002 and 2008, we examined GPS measurements of TEC (Total Electron Content) and neutral and electron densities measured by CHAMP satellite. Total of fifteen TID events with clear southward moving structures in the GPS-TEC measurements are found by simultaneous ground-satellite measurements. On 2002, simultaneous events are only observed in January (1 event) and February (4 events). On 2008, ten events are observed around winter months (January (3 events), February (5), March (1), and October (1)). Neutral and electron densities measured by CHAMP show quasi-periodic fluctuations throughout the passages for all events. The CHAMP satellite crossed at least one clear TID phase front for all the events. We fitted a sinusoidal function to both ground and satellite data to obtain the frequencies and phase of the observed variations. We calculated the corresponding phase relationships between TEC variations and neutral and electron densities measured by CHAMP to categorize the events. In the presentations we report correspondence of these TID structures seen in the simultaneous ground-satellite observations by GPS-TEC and CHAMP, and discuss their phase relationship to identify the source of the daytime TIDs and specify how much of the observed variations are showing clear frequencies/or not in the nature at middle latitudes.

Simultaneous Observations of TADs in GOCE, CHAMP and GRACE Density Data Compared with CTIPe

NASA Astrophysics Data System (ADS)

Bruinsma, S. L.; Fedrizzi, M.

2012-12-01

The accelerometers on the CHAMP and GRACE satellites have made it possible to accumulate near-continuous records of thermosphere density between about 300 and 490 km since May 2001, and July 2002, respectively. Since November 2009, a third gravity field satellite mission, ESA's GOCE, is in a very low and near heliosynchronous dawn-dusk orbit at about 270 km. The spacecraft is actively maintained at that constant altitude using an ion propulsion engine that compensates the aerodynamic drag in the flight direction. The thrust level, combined with accelerometer and satellite attitude data, is used to compute atmospheric densities and cross-track winds. The response of the thermosphere to geomagnetic disturbances, i.e., space weather, has been extensively studied using the exceptional datasets of CHAMP and GRACE. Thanks to GOCE we now have a third excellent data set for these studies. In this presentation we will show the observed density and its variability for the geomagnetic storm of 5 April 2010, and compare it with predictions along the orbits obtained from a self-consistent physics-based coupled model of the thermosphere, ionosphere, plasmasphere and electrodynamics (CTIPe). For this storm, the CHAMP and GOCE orbit planes were perpendicular (12/24 Local Solar Time, and 6/18 LST, respectively) and the altitude difference was only approximately 30 km. The GRACE densities are at a much higher altitude of about 475 km. Wave-like features are revealed or enhanced after filtering of the densities and calculation of relative density variations. Traveling Atmospheric Disturbances are observed in the data, and the model's fidelity in reproducing the waves is evaluated.

Effect of the Children's Health Activity Motor Program on Motor Skills and Self-Regulation in Head Start Preschoolers: An Efficacy Trial.

PubMed

Robinson, Leah E; Palmer, Kara K; Bub, Kristen L

2016-01-01

Self-regulatory skills are broadly defined as the ability to manage emotions, focus attention, and inhibit some behaviors while activating others in accordance with social expectations and are an established indicator of academic success. Growing evidence links motor skills and physical activity to self-regulation. This study examined the efficacy of a motor skills intervention (i.e., the Children's Health Activity Motor Program, CHAMP) that is theoretically grounded in Achievement Goal Theory on motor skill performance and self-regulation in Head Start preschoolers. A sample of 113 Head Start preschoolers (Mage = 51.91 ± 6.5 months; 49.5% males) were randomly assigned to a treatment (n = 68) or control (n = 45) program. CHAMP participants engaged in 15, 40-min sessions of a mastery climate intervention that focused on the development of motor skills over 5 weeks while control participants engaged in their normal outdoor recess period. The Delay of Gratification Snack Task was used to measure self-regulation and the Test of Gross Motor Development-2nd Edition was used to assess motor skills. All measures were assessed prior to and following the intervention. Linear mixed models were fit for both self-regulation and motor skills. Results revealed a significant time × treatment interaction (p < 0.001). In regard to motor skills, post hoc comparisons found that all children improved their motor skills (p < 0.05), but the CHAMP group improved significantly more than the control group (p < 0.001). Children in CHAMP maintained their self-regulation scores across time, while children in the control group scored significantly lower than the CHAMP group at the posttest (p < 0.05). CHAMP is a mastery climate movement program that enhance skills associated with healthy development in children (i.e., motor skills and self-regulation). This efficacy trial provided evidence that CHAMP helped maintain delay of gratification in preschool age children and significantly improved motor skills while participating in outdoor recess was not effective. CHAMP could help contribute to children's learning-related skills and physical development and subsequently to their academic success.

Case study of inclined sporadic E layers in the Earth's ionosphere observed by CHAMP/GPS radio occultations: Coupling between the tilted plasma layers and internal waves

NASA Astrophysics Data System (ADS)

Gubenko, Vladimir N.; Pavelyev, A. G.; Kirillovich, I. A.; Liou, Y.-A.

2018-04-01

We have used the radio occultation (RO) satellite data CHAMP/GPS (Challenging Minisatellite Payload/Global Positioning System) for studying the ionosphere of the Earth. A method for deriving the parameters of ionospheric structures is based upon an analysis of the RO signal variations in the phase path and intensity. This method allows one to estimate the spatial displacement of a plasma layer with respect to the ray perigee, and to determine the layer inclination and height correction values. In this paper, we focus on the case study of inclined sporadic E (Es) layers in the high-latitude ionosphere based on available CHAMP RO data. Assuming that the internal gravity waves (IGWs) with the phase-fronts parallel to the ionization layer surfaces are responsible for the tilt angles of sporadic plasma layers, we have developed a new technique for determining the parameters of IGWs linked with the inclined Es structures. A small-scale internal wave may be modulating initially horizontal Es layer in height and causing a direction of the plasma density gradient to be rotated and aligned with that of the wave propagation vector k. The results of determination of the intrinsic wave frequency and period, vertical and horizontal wavelengths, intrinsic vertical and horizontal phase speeds, and other characteristics of IGWs under study are presented and discussed.

Features of highly structured equatorial plasma irregularities deduced from CHAMP observations

NASA Astrophysics Data System (ADS)

Xiong, C.; Lühr, H.; Ma, S. Y.; Stolle, C.; Fejer, B. G.

2012-08-01

In this study five years of CHAMP (Challenging Mini-satellite Payload) fluxgate magnetometer (FGM) data is used to investigate the characteristics of Equatorial Plasma Bubbles (EPBs). We filtered the FGM data by using band-passes with four different cut-off periods to get the EPBs with different maximum spatial scale sizes in the meridional plane ranging from 76-608 km. Associated with the EPB observations at about 400 km, the typical altitude of CHAMP during the year 2000-2005, we also investigate the post-sunset equatorial vertical plasma drift data from ROCSAT-1 (Republic of China Satellite 1). Since the height of the F-layer is highly correlated with the vertical plasma drift and solar flux, we sorted the ROCSAT-1 data into different groups by F10.7. From the integrated vertical drift we have estimated the post-sunset uplift of the ionosphere. By comparing the properties of EPB occurrence for different scale sizes with the global distribution of plasma vertical uplift, we have found that EPBs reaching higher altitudes are more structured than those which are sampled by CHAMP near the top side of the depleted fluxtube. Such a result is in accord with 3-D model simulations (Aveiro and Hysell, 2010). Small-scale EPB structures are observed by CHAMP when the irregularities reach apex heights of 800 km and more. Such events are encountered primarily in the Brazilian sector during the months around November, when the post-sunset vertical plasma drift is high.

Marine Geoid Undulation Assessment Over South China Sea Using Global Geopotential Models and Airborne Gravity Data

NASA Astrophysics Data System (ADS)

Yazid, N. M.; Din, A. H. M.; Omar, K. M.; Som, Z. A. M.; Omar, A. H.; Yahaya, N. A. Z.; Tugi, A.

2016-09-01

Global geopotential models (GGMs) are vital in computing global geoid undulations heights. Based on the ellipsoidal height by Global Navigation Satellite System (GNSS) observations, the accurate orthometric height can be calculated by adding precise and accurate geoid undulations model information. However, GGMs also provide data from the satellite gravity missions such as GRACE, GOCE and CHAMP. Thus, this will assist to enhance the global geoid undulations data. A statistical assessment has been made between geoid undulations derived from 4 GGMs and the airborne gravity data provided by Department of Survey and Mapping Malaysia (DSMM). The goal of this study is the selection of the best possible GGM that best matches statistically with the geoid undulations of airborne gravity data under the Marine Geodetic Infrastructures in Malaysian Waters (MAGIC) Project over marine areas in Sabah. The correlation coefficients and the RMS value for the geoid undulations of GGM and airborne gravity data were computed. The correlation coefficients between EGM 2008 and airborne gravity data is 1 while RMS value is 0.1499.In this study, the RMS value of EGM 2008 is the lowest among the others. Regarding to the statistical analysis, it clearly represents that EGM 2008 is the best fit for marine geoid undulations throughout South China Sea.

Effect of the Children’s Health Activity Motor Program on Motor Skills and Self-Regulation in Head Start Preschoolers: An Efficacy Trial

PubMed Central

Robinson, Leah E.; Palmer, Kara K.; Bub, Kristen L.

2016-01-01

Self-regulatory skills are broadly defined as the ability to manage emotions, focus attention, and inhibit some behaviors while activating others in accordance with social expectations and are an established indicator of academic success. Growing evidence links motor skills and physical activity to self-regulation. This study examined the efficacy of a motor skills intervention (i.e., the Children’s Health Activity Motor Program, CHAMP) that is theoretically grounded in Achievement Goal Theory on motor skill performance and self-regulation in Head Start preschoolers. A sample of 113 Head Start preschoolers (Mage = 51.91 ± 6.5 months; 49.5% males) were randomly assigned to a treatment (n = 68) or control (n = 45) program. CHAMP participants engaged in 15, 40-min sessions of a mastery climate intervention that focused on the development of motor skills over 5 weeks while control participants engaged in their normal outdoor recess period. The Delay of Gratification Snack Task was used to measure self-regulation and the Test of Gross Motor Development-2nd Edition was used to assess motor skills. All measures were assessed prior to and following the intervention. Linear mixed models were fit for both self-regulation and motor skills. Results revealed a significant time × treatment interaction (p < 0.001). In regard to motor skills, post hoc comparisons found that all children improved their motor skills (p < 0.05), but the CHAMP group improved significantly more than the control group (p < 0.001). Children in CHAMP maintained their self-regulation scores across time, while children in the control group scored significantly lower than the CHAMP group at the posttest (p < 0.05). CHAMP is a mastery climate movement program that enhance skills associated with healthy development in children (i.e., motor skills and self-regulation). This efficacy trial provided evidence that CHAMP helped maintain delay of gratification in preschool age children and significantly improved motor skills while participating in outdoor recess was not effective. CHAMP could help contribute to children’s learning-related skills and physical development and subsequently to their academic success. PMID:27660751

Ground and CHAMP observations of field-aligned current circuits generated by lower atmospheric disturbances and expectations to the SWARM to clarify their three dimensional structure

NASA Astrophysics Data System (ADS)

Iyemori, Toshihiko; Nakanishi, Kunihito; Aoyama, Tadashi; Lühr, Hermann

2014-05-01

Acoustic gravity waves propagated to the ionosphere cause dynamo currents in the ionosphere. They divert along geomagnetic field lines of force to another hemisphere accompanying electric field and then flow in the ionosphere of another hemisphere by the electric field forming closed current circuits. The oscillating current circuits with the period of acoustic waves generate magnetic variations on the ground, and they are observed as long period geomagnetic pulsations. This effect has been detected during big earthquakes, strong typhoons, tornados etc. On a low-altitude satellite orbit, the spatial distribution (i.e., structure) of the current circuits along the satellite orbit should be detected as temporal magnetic oscillations, and the effect is confirmed by a CHAMP data analysis. On the spatial structure, in particular, in the longitudinal direction, it has been difficult to examine by a single satellite or from ground magnetic observations. The SWARM satellites will provide an unique opportunity to clarify the three dimensional structure of the field-aligned current circuits.

Assessing the Impact of Earth Radiation Pressure Acceleration on Low-Earth Orbit Satellites

NASA Astrophysics Data System (ADS)

Vielberg, Kristin; Forootan, Ehsan; Lück, Christina; Kusche, Jürgen; Börger, Klaus

2017-04-01

The orbits of satellites are influenced by several external forces. The main non-gravitational forces besides thermospheric drag, acting on the surface of satellites, are accelerations due to the Earth and Solar Radiation Pres- sure (SRP and ERP, respectively). The sun radiates visible and infrared light reaching the satellite directly, which causes the SRP. Earth also emits and reflects the sunlight back into space, where it acts on satellites. This is known as ERP acceleration. The influence of ERP increases with decreasing distance to the Earth, and for low-earth orbit (LEO) satellites ERP must be taken into account in orbit and gravity computations. Estimating acceler- ations requires knowledge about energy emitted from the Earth, which can be derived from satellite remote sensing data, and also by considering the shape and surface material of a satellite. In this sensitivity study, we assess ERP accelerations based on different input albedo and emission fields and their modelling for the satellite missions Challenging Mini-Satellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE). As input fields, monthly 1°x1° products of Clouds and the Earth's Radiant En- ergy System (CERES), L3 are considered. Albedo and emission models are generated as latitude-dependent, as well as in terms of spherical harmonics. The impact of different albedo and emission models as well as the macro model and the altitude of satellites on ERP accelerations will be discussed.

Traveling Atmospheric Disturbances (TADs) in the thermosphere inferred from accelerometer data at three altitudes

NASA Astrophysics Data System (ADS)

Bruinsma, Sean; Forbes, Jeffrey

2010-05-01

Densities derived from accelerometer measurements on the GRACE, CHAMP and Air Force/SETA satellites near 490, 390, and 220 km, respectively, are used to elucidate global-scale characteristics of traveling atmospheric disturbances. The accelerometers on the CHAMP and GRACE satellites have made it possible to accumulate near-continuous records of thermosphere density between about 320 and 490 km since May 2001, and July 2002, respectively. They have recorded the response to virtually every significant geomagnetic storm during this period. CHAMP and GRACE are in (near) polar and quasi-circular orbits, sampling 24 hr local time approximately every 4 and 5 months, respectively. These capabilities offer unique opportunities to study the temporal and latitudinal responses of the thermosphere to geomagnetic disturbances. The Air Force/SETA accelerometer data have also been processed, but the analysis is more complicated due to data gaps. Significant and unambiguous TAD activity in the observed response of the thermosphere was detected for about 25 events with CHAMP and GRACE, and less than 10 with SETA. The atmospheric variability is evaluated by de-trending the data, allowing the extraction of specific ranges in horizontal scale, and analyzing density "residuals". The scale of the perturbation is decisive for its lifetime and relative amplitude. Sometimes the disturbances represent wave-like structures propagating far from the source, and these so-called ‘TADs' were detected and described for the May 2003 storm for the first time. Some TADs traveled over the pole into the opposite hemisphere; this was found in both CHAMP and GRACE data. Most TADs propagate equatorward, but poleward propagating TADs have on occasion been detected too. The estimated speeds and amplitudes of the observed TADs, and their dependence on altitude and solar and geomagnetic activity in particular, will be presented in this poster.

Intraannual variability of tides in the thermosphere from model simulations and in situ satellite observations

NASA Astrophysics Data System (ADS)

Häusler, K.; Hagan, M. E.; Forbes, J. M.; Zhang, X.; Doornbos, E.; Bruinsma, S.; Lu, G.

2015-01-01

In this paper, we provide insights into limitations imposed by current satellite-based strategies to delineate tidal variability in the thermosphere, as well as the ability of a state-of-the-art model to replicate thermospheric tidal determinations. Toward this end, we conducted a year-long thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) simulation for 2009, which is characterized by low solar and geomagnetic activity. In order to account for tropospheric waves and tides propagating upward into the ˜30-400 km model domain, we used 3-hourly MERRA (Modern-Era Retrospective Analysis for Research and Application) reanalysis data. We focus on exospheric tidal temperatures, which are also compared with 72 day mean determinations from combined Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) satellite observations to assess the model's capability to capture the observed tidal signatures and to quantify the uncertainties associated with the satellite exospheric temperature determination technique. We found strong day-to-day tidal variability in TIME-GCM that is smoothed out when averaged over as few as ten days. TIME-GCM notably overestimates the 72 day mean eastward propagating tides observed by CHAMP/GRACE, while capturing many of the salient features of other tidal components. However, the CHAMP/GRACE tidal determination technique only provides a gross climatological representation, underestimates the majority of the tidal components in the climatological spectrum, and moreover fails to characterize the extreme variability that drives the dynamics and electrodynamics of the ionosphere-thermosphere system. A multisatellite mission that samples at least six local times simultaneously is needed to provide this quantification.

On the capability of SWARM for estimating time-variable gravity fields and mass variations

NASA Astrophysics Data System (ADS)

Reubelt, Tilo; Baur, Oliver; Weigelt, Matthias; Sneeuw, Nico

2013-04-01

Recently, the implementation of the GRACE Follow-On mission has been approved. However, this successor of GRACE is planned to become operational in 2017 at the earliest. In order to fill the impending gap of 3-4 years between GRACE and GRACE-FO, the capability of the magnetic field mission SWARM as a gap filler for time-variable gravity field determination has to be investigated. Since the three SWARM satellites, where two of them fly on a pendulum formation, are equipped with high-quality GPS receivers and accelerometers, orbit analysis from high-low Satellite-to-Satellite Tracking (hl-SST) can be applied for geopotential recovery. As data analysis from CHAMP and GRACE has shown, the detection of annual gravity signals and gravity trends from hl-SST is possible for long-wavelength features corresponding to a Gaussian radius of 1000 km, although the accuracy of a low-low SST mission like GRACE cannot be reached. However, since SWARM is a three-satellite constellation and might provide GPS data of higher quality compared to previous missions, improved gravity field recovery can be expected. We present detailed closed-loop simulation studies for a 5 years period based on time-variable gravity caused by mass changes in the hydrosphere, cryosphere and solid Earth. Models for these variations are used to simulate the SWARM satellite orbits. We recover time-variable gravity from orbit analysis adopting the acceleration approach. Finally, we convert time-variable gravity to mass change in order to compare with the a priori model input.

An Evaluation of Recent Gravity Models wrt. Altimeter Satellite Missions

NASA Technical Reports Server (NTRS)

Lemoine, Frank G.; Zelensky, N. P.; Luthcke, S. B.; Beckley, B. D.; Chinn, D. S.; Rowlands, D. D.

2003-01-01

With the launch of CHAMP and GRACE, we have entered a new phase in the history of satellite geodesy. For the first time, geopotential models are now available based almost exclusively on satellite-satellite tracking either with GPS in the case of the CHAMP-based geopotential models, or co-orbital intersatellite ultra-precise ranging in the case of GRACE. Different groups have analyzed these data, and produced a series of geopotential models (e.g., EIGENlS, EIGEN2, GGM0lS, GGMOlC) that incorporate the new data. We will compare the performance of these "newer" geopotential models with the standard models now used for computations, (e.g., JGM-3, BGM-96, PGS7727, and GRIMS-C1) for TOPEX, JASON, Geosat-Follow-On (GFO), and Envisat using standard metrics such as SLR RMS of fit, altimeter crossovers, and orbit overlaps. Where covariances are available we can evaluate the predicted geographically correlated orbit error. These predicted results can be compared with the Earth-fixed differences between dynamic and reduced-dynamic orbits to test the predictive accuracy of the covariances, as well as to calibrate the error of the solutions.

Western Continental Margin of India - Re-look using potential field data

NASA Astrophysics Data System (ADS)

Rajaram, M.; S P, A.

2008-05-01

The Western Continental Margin of India (WCMI) evolved as a result of rifting between India and Madagascar that took place during mid Cretaceous (~88Ma).The WCMI is equally important in terms of natural resources as well as research point of view. The major tectonic elements in the western offshore includes the Laxmi and Chagos- Laccadive ridge dividing the WCMI and the adjoining Arabian sea into two basins, Pratap Ridge, Alleppey platform etc. Different theories have been proposed for the evolution of each of these tectonic elements. In the current paper we look at geopotential data on the west coast of India and the western off-shore. The data sets utilized include Satellite derived High Resolution Free Air Gravity data over the off-shore, Bouguer data onland, Champ Satellite Magnetic data, published Marine Magnetic data collected by ONGC, NIO, ground magnetic data over west cost collected by IIG and available aeromagnetic data. From the free air gravity anomaly the structural details of the western offshore can be delineated. The Euler depths of FAG depict deep solutions associated with Pratap Ridge, Comorin Ridge, the west coast fault and the Laxmi Ridge. These may be associated with continental margin and continental fragments. From the aeromagnetic and marine magnetic data it is evident that the West Coast Fault is dissected at several places. The shallow circular feature associated with Bombay High is evident both on the FAG and the analytic signal derived from satellite Magnetic data. The crustal magnetic thickness from MF5 lithospheric model of the Champ appears to suggest that the continental crust extends up to the Chagos- Laccadive ridge. Based on the analysis of these geopotential data sets the various theories for the evolution of the WCMI will be evaluated and these results will be presented.

Change the management of patients with heart failure: Rationale and design of the CHAMP-HF registry.

PubMed

DeVore, Adam D; Thomas, Laine; Albert, Nancy M; Butler, Javed; Hernandez, Adrian F; Patterson, J Herbert; Spertus, John A; Williams, Fredonia B; Turner, Stuart J; Chan, Wing W; Duffy, Carol I; McCague, Kevin; Mi, Xiaojuan; Fonarow, Gregg C

2017-07-01

Heart failure (HF) with reduced ejection fraction (HFrEF) is a common and costly condition that diminishes patients' health status and confers a poor prognosis. Despite the availability of multiple guideline-recommended pharmacologic and cardiac device therapies for patients with chronic HFrEF, outcomes remain suboptimal. Currently, there is limited insight into the rationale underlying clinical decisions by health care providers and patient factors that guide the use and intensity of outpatient HF treatments. A better understanding of current practice patterns has the potential to improve patients' outcomes. The CHAnge the Management of Patients with Heart Failure (CHAMP-HF) registry will evaluate the care and outcomes of patients with chronic HFrEF by assessing real-world treatment patterns, as well as the reasons for and barriers to medication treatment changes. CHAMP-HF will enroll approximately 5,000 patients with chronic HFrEF (left ventricular ejection fraction ≤40%) at approximately 150 US sites, and patients will be followed for a maximum duration of 24 months. Participating sites will collect data from both providers (HF history, examination findings, results of diagnostic studies, pharmacotherapy treatment patterns, decision-making factors, and clinical outcomes) and patients (medication adherence and patient-reported outcomes). The CHAMP-HF registry will provide a unique opportunity to study practice patterns and the adoption of new HF therapies across a diverse mix of health care providers and outpatient practices in the United States that care for HFrEF patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Time-Variable Gravity from Space: Quarter Century of Observations, Mysteries, and Prospects

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

2003-01-01

Any large mass transport in the Earth system produces changes in the gravity field. Via the space geodetic technique of satellite-laser ranging in the last quarter century, the Earth s dynamic oblateness J2 (the lowest-degree harmonic component of the gravity field) has been observed to undergo a slight decrease - until around 1998, when it switched quite suddenly to an increase trend which has continued to date. The secular decrease in J2 has long been attributed primarily to the post-glacial rebound in the mantle; the present increase signifies an even larger change in global mass distribution whose J2 effect overshadows that of the post-glacial rebound, at least over interannual timescales. Intriguing evidences have been found in the ocean water distribution, especially in the extratropical Pacific basins, that may be responsible for this 52 change. New techniques based on satellite-to-satellite tracking will yield greatly improved observations for time-variable gravity, with much higher precision and spatial resolution @e., much higher harmonic degrees). The most important example is the GRACE mission launched in March 2002, following the success of the CHAMP mission. Such observations are becoming a new and powerful tool for remote sensing of geophysical fluid processes that involve larger-scale mass transports.

Evaluation of Gravitational Field Models Based on the Laser Range Observation of Low Earth Orbit Satellites

NASA Astrophysics Data System (ADS)

Wang, H. B.; Zhao, C. Y.; Zhang, W.; Zhan, J. W.; Yu, S. X.

2015-09-01

The Earth gravitational filed model is a kind of important dynamic model in satellite orbit computation. In recent years, several space gravity missions have obtained great success, prompting a lot of gravitational filed models to be published. In this paper, 2 classical models (JGM3, EGM96) and 4 latest models, including EIGEN-CHAMP05S, GGM03S, GOCE02S, and EGM2008 are evaluated by being employed in the precision orbit determination (POD) and prediction, based on the laser range observation of four low earth orbit (LEO) satellites, including CHAMP, GFZ-1, GRACE-A, and SWARM-A. The residual error of observation in POD is adopted to describe the accuracy of six gravitational field models. We show the main results as follows: (1) for LEO POD, the accuracies of 4 latest models (EIGEN-CHAMP05S, GGM03S, GOCE02S, and EGM2008) are at the same level, and better than those of 2 classical models (JGM3, EGM96); (2) If taking JGM3 as reference, EGM96 model's accuracy is better in most situations, and the accuracies of the 4 latest models are improved by 12%-47% in POD and 63% in prediction, respectively. We also confirm that the model's accuracy in POD is enhanced with the increasing degree and order if they are smaller than 70, and when they exceed 70 the accuracy keeps stable, and is unrelated with the increasing degree, meaning that the model's degree and order truncated to 70 are sufficient to meet the requirement of LEO orbit computation with centimeter level precision.

VizieR Online Data Catalog: ChaMP X-ray point source catalog (Kim+, 2007)

NASA Astrophysics Data System (ADS)

Kim, M.; Kim, D.-W.; Wilkes, B. J.; Green, P. J.; Kim, E.; Anderson, C. S.; Barkhouse, W. A.; Evans, N. R.; Ivezic, Z.; Karovska, M.; Kashyap, V. L.; Lee, M. G.; Maksym, P.; Mossman, A. E.; Silverman, J. D.; Tananbaum, H. D.

2009-01-01

We present the Chandra Multiwavelength Project (ChaMP) X-ray point source catalog with ~6800 X-ray sources detected in 149 Chandra observations covering ~10deg2. The full ChaMP catalog sample is 7 times larger than the initial published ChaMP catalog. The exposure time of the fields in our sample ranges from 0.9 to 124ks, corresponding to a deepest X-ray flux limit of f0.5-8.0=9x10-16ergs/cm2/s. The ChaMP X-ray data have been uniformly reduced and analyzed with ChaMP-specific pipelines and then carefully validated by visual inspection. The ChaMP catalog includes X-ray photometric data in eight different energy bands as well as X-ray spectral hardness ratios and colors. To best utilize the ChaMP catalog, we also present the source reliability, detection probability, and positional uncertainty. (10 data files).

Cross-Cultural Adaptation of the CHAMPS Questionnaire in French Canadians with COPD

PubMed Central

Mak, Susanne; Soicher, Judith E.; Mayo, Nancy E.; Wood-Dauphinee, Sharon; Bourbeau, Jean

2016-01-01

Physical activity is difficult to measure in individuals with COPD. The Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire demonstrated strong clinometric properties when used with the elderly and with those affected by chronic disease. Study objectives were to translate, culturally adapt the CHAMPS into French, and reexamine its test-retest reliability and construct validity in French and English Canadians with COPD. This paper presents the cross-cultural adaptation of the CHAMPS; results of its clinometric testing will be described in another article. The CHAMPS examines the degree of physical activity performed in a typical week through two summary scales, caloric expenditure and activity frequency. The CHAMPS was only in English; thus, a cross-cultural adaptation was needed to translate the CHAMPS into French for use in French Canadians with COPD. Cross-cultural adaptation consisted of forward and back translation, with expert review at each stage of translation: minor inconsistencies were uncovered and rectified. Five French participants with COPD completed the finalized Canadian French CHAMPS and participated in cognitive debriefing; no problematic items were identified. A structured and stepwise, cross-cultural adaptation process produced the Canadian French CHAMPS, with items of equivalent meaning to the English version, for use in French Canadians with COPD. PMID:27445570

Cross-Cultural Adaptation of the CHAMPS Questionnaire in French Canadians with COPD.

PubMed

Mak, Susanne; Soicher, Judith E; Mayo, Nancy E; Wood-Dauphinee, Sharon; Bourbeau, Jean

2016-01-01

Physical activity is difficult to measure in individuals with COPD. The Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire demonstrated strong clinometric properties when used with the elderly and with those affected by chronic disease. Study objectives were to translate, culturally adapt the CHAMPS into French, and reexamine its test-retest reliability and construct validity in French and English Canadians with COPD. This paper presents the cross-cultural adaptation of the CHAMPS; results of its clinometric testing will be described in another article. The CHAMPS examines the degree of physical activity performed in a typical week through two summary scales, caloric expenditure and activity frequency. The CHAMPS was only in English; thus, a cross-cultural adaptation was needed to translate the CHAMPS into French for use in French Canadians with COPD. Cross-cultural adaptation consisted of forward and back translation, with expert review at each stage of translation: minor inconsistencies were uncovered and rectified. Five French participants with COPD completed the finalized Canadian French CHAMPS and participated in cognitive debriefing; no problematic items were identified. A structured and stepwise, cross-cultural adaptation process produced the Canadian French CHAMPS, with items of equivalent meaning to the English version, for use in French Canadians with COPD.

Mapping the gravity field in coastal areas: feasibility and interest of a new airborne planar gradiometer concept

NASA Astrophysics Data System (ADS)

Douch, Karim; Panet, Isabelle; Foulon, Bernard; Christophe, Bruno; Pajot-Métivier, Gwendoline; Diament, Michel

2014-05-01

Satellite missions such as CHAMP, GRACE and GOCE have led to an unprecedented improvement of global gravity field models during the past decade. However, for many applications these global models are not sufficiently accurate when dealing with wavelengths shorter than 100 km. This is all the more true in areas where gravity data are scarce and uneven as for instance in the poorly covered land-sea transition area. We suggest here, in line with spatial gravity gradiometry, airborne gravity gradiometry as a convenient way to amplify the sensitivity to short wavelengths and to cover homogeneously coastal region. Moreover, the directionality of the gravity gradients gives new information on the geometry of the gravity field and therefore of the causative bodies. In this respect, we analyze here the performances of a new airborne electrostatic acceleration gradiometer, GREMLIT, which permits along with ancillary measurements to determine the horizontal gradients of the horizontal components of the gravitational field in the instrumental frame. GREMLIT is composed of a compact assembly of 4 planar electrostatic accelerometers inheriting from technologies developed by ONERA for spatial accelerometers. After an overview of the functionals of the gravity field that are of interest for coastal oceanography, passive navigation and hydrocarbon exploration, we present the corresponding required precision and resolution. Then, we investigate the influence of the different parameters of the survey, such as altitude or cross-track distance, on the resolution and precision of the final measurements. To do so, we design numerical simulations of airborne survey performed with GREMLIT and compute the total error budget on the gravity gradients. Based on this error analysis, we infer by a method of error propagation the uncertainty on the different functionals of the gravity potential used for each application. This finally enables us to conclude on the requirements for a high resolution mapping of the gravity field in coastal areas.

Magsat to CHAMP: Magnetic Satellite Explorations of Lithospheric Anomalies over Kursk, Bangui and the Antarctic

NASA Technical Reports Server (NTRS)

Kim, H.; Taylor, Patrick T.; vonFrese, R. R.; Kim, J. W.

2004-01-01

We compare crustal magnetic anomaly maps over the Kursk (Russia) and Bangui (Central African Republic) isolated anomalies and the Antarctic derived from the Magsat, \\Orsted and CHAMP satellite fields. We wish to demonstrate how progress in satellite magnetic missions has improved the recovery of the crustal magnetic field. The 6-month long Magsat mission of 25 years ago generated two major methods of processing satellite magnetic anomaly data for lithospheric studies. The first was a global perspective using spherical harmonics that emphasize the more regional and global lithospheric fields. However, these fields commonly do not resolve local anomaly features in any detail. Therefore a second procedure involved the use of the individual satellite orbit or track data to recover small-scale anomalies on a regional scale. We present results over prominent magnetic anomalies such as Kursk, Bangui and the large Antarctic continent that demonstrate how the various analysis methods affect the recovery of crustal anomalies. The more recent \\Orsted and CHAMP missions are successfully recording data with an improved accuracy and with full spatial and temporal coverage. We show and interpret the total magnetic intensity anomaly maps over these areas from all three satellite magnetometer data sets.

A multi-year comparison of lower stratospheric temperatures from CHAMP radio occultation data with MSU/AMSU records

NASA Astrophysics Data System (ADS)

Steiner, A. K.; Kirchengast, G.; Borsche, M.; Foelsche, U.; Schoengassner, T.

2007-11-01

Long-term upper air temperature records have been established by different groups with considerable effort from radiosonde data and from satellite based (Advanced) Microwave Sounding Unit (MSU/AMSU) measurements, the latter providing information on layer-average stratospheric and tropospheric brightness temperatures. Comparisons of the temperature series show discrepancies not only with respect to radiosonde data but also between MSU data sets stemming from different retrievals. In this context the Global Navigation Satellite System radio occultation (RO) technique offers new possibilities by providing high quality observations of the atmosphere in an active limb sounding mode. RO temperature climatologies have been constructed at the WegCenter/UniGraz based on RO observations of the CHAllenging Minisatellite Payload for geoscientific research (CHAMP) satellite since September 2001, and based on a few months of RO data from other satellite missions (SAC-C, GRACE, COSMIC). Focusing on the MSU lower stratosphere channel (TLS), synthetic TLS temperatures were calculated by applying global weighting functions to zonal-mean monthly mean RO temperature climatology profiles for September 2001-December 2006. These synthetic CHAMP TLS temperatures were compared to recent MSU TLS records from the University of Alabama in Huntsville (UAH, USA) and from Remote Sensing Systems (RSS, USA), as well as to synthetic TLS temperatures from HadAT2 radiosonde data (Hadley Centre/MetOffice, UK) and ECMWF (European Centre for Medium-Range Weather Forecasts) analyses. In terms of TLS temperature anomalies, overall very good agreement of CHAMP temperature anomalies with UAH, RSS, and ECMWF anomalies was found for intra-annual variability (RMS difference of de-trended data <0.1 K globally, 0.1 K in the tropics, <0.25 K in the extratropics), while HadAT2 anomalies show larger differences (factor of two globally and more in the extratropics). Regarding 2001-2006 trends, UAH and RSS exhibit a statistically significant cooling trend difference to CHAMP globally (-0.30 to -0.36 K/5 yrs), stemming mainly from the tropics (-0.40 to -0.42 K/5 yrs), while in the extratropics the cooling trend differences are not significant. The contribution of known error sources regarding the RO data and the related synthetic-MSU computation procedure is about an order of magnitude smaller than these trend differences. Resolution of the trend discrepancy thus requires either additional, so far overlooked, sources of error in the RO TLS record or the presence of currently unresolved biases in the MSU records. SAC-C, GRACE, and COSMIC TLS temperatures closely match CHAMP temperatures, indicating the consistency and homogeneity of the RO data series. The results underpin the benefit of having multiple independent estimates of the same variable from different instruments for detecting residual weaknesses in otherwise high-quality climate records. Continued inter-comparison, and exploiting the traceability of the RO data to the universal time standard (UTC), then enables us to further reduce the uncertainty in the climate records in absolute terms.

Promoting ball skills in preschool-age girls.

PubMed

Veldman, Sanne L C; Palmer, Kara K; Okely, Anthony D; Robinson, Leah E

2017-01-01

Evidence supports that girls are less proficient than boys at performing ball skills. This study examined the immediate and long-term effects of a ball skill intervention on preschool-age girls' ball skill performance. Randomized controlled trial. Girls (M age =47.24±7.38 months) were randomly assigned to a high autonomy, mastery-based 9-week motor skill intervention (the Children's Health Activity Motor Program; CHAMP, 540min; n=38) or a control group (free-play; n=16). Ball skill proficiency was assessed at pretest, posttest, and retention test (after 9 weeks) using the object control subscale of the Test of Gross Motor Development - 2nd Edition. Treatment efficacy was examined using linear mixed models. Two models were fit: one for short-term changes (pretest to posttest) and one for long-term changes (pretest to retention). Linear mixed models revealed a significantly time*treatment interaction for both models. Post hoc analysis confirmed that girls in CHAMP experienced significant gains in ball skills from pretest to posttest (p<.001) and pretest to retention (p<.001). Moreover, girls in CHAMP were no different from the control group at pretest (p>.05) but had significantly higher ball skills scores at both posttest (p<.001) and retention (p<.001). This study demonstrates the positive effects of a ball skill intervention (i.e., CHAMP) on improving girls' ball skills both short- and long-term. Findings suggest that early childhood interventions that focus on the development of ball skills in young girls might be an avenue to improve girls' ball skill performance. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Recent changes of the Earth's core derived from satellite observations of magnetic and gravity fields.

PubMed

Mandea, Mioara; Panet, Isabelle; Lesur, Vincent; de Viron, Olivier; Diament, Michel; Le Mouël, Jean-Louis

2012-11-20

To understand the dynamics of the Earth's fluid, iron-rich outer core, only indirect observations are available. The Earth's magnetic field, originating mainly within the core, and its temporal variations can be used to infer the fluid motion at the top of the core, on a decadal and subdecadal time-scale. Gravity variations resulting from changes in the mass distribution within the Earth may also occur on the same time-scales. Such variations include the signature of the flow inside the core, though they are largely dominated by the water cycle contributions. Our study is based on 8 y of high-resolution, high-accuracy magnetic and gravity satellite data, provided by the CHAMP and GRACE missions. From the newly derived geomagnetic models we have computed the core magnetic field, its temporal variations, and the core flow evolution. From the GRACE CNES/GRGS series of time variable geoid models, we have obtained interannual gravity models by using specifically designed postprocessing techniques. A correlation analysis between the magnetic and gravity series has demonstrated that the interannual changes in the second time derivative of the core magnetic field under a region from the Atlantic to Indian Ocean coincide in phase with changes in the gravity field. The order of magnitude of these changes and proposed correlation are plausible, compatible with a core origin; however, a complete theoretical model remains to be built. Our new results and their broad geophysical significance could be considered when planning new Earth observation space missions and devising more sophisticated Earth's interior models.

Time-Variable Gravity from Space: Quarter Century of Observations, Mysteries, and Prospects

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

2003-01-01

Any large mass transport in the Earth system produces changes in the gravity field. Via the space geodetic technique of satellite-laser ranging in the last quarter century, the Earth's dynamic oblateness J2 (the lowest-degree harmonic component of the gravity field) has been observed to undergo a slight decrease -- until around 1998, when it switched quite suddenly to an increase trend which has continued to date. The secular decrease in J2 has long been attributed primarily to the post-glacial rebound in the mantle; the present increase signifies an even larger change in global mass distribution whose J2 effect overshadows that of the post-glacial rebound, at least over interannual timescales. Intriguing evidences have been found in the ocean water distribution, especially in the extratropical Pacific basins, that may be responsible for this J2 change. New techniques based on satellite-to-satellite tracking will yield greatly improved observations for time-variable gravity, with much higher precision and spatial resolution (i.e., much higher harmonic degrees). The most important example is the GRACE mission launched in March 2002, following the success of the CHAMP mission. In addition, although less precise than GRACE, the GPS/Meteorology constellation mission COSMIC, with 6 mini-satellites to be launched in late 2005, is expected to provide continued and complementary time-variable gravity observations. Such observations are becoming a new and powerful tool for remote sensing of geophysical fluid processes that involve larger-scale mass transports.

Selected Gravity Models in Terms of the fit to the GOCE Kinematic Orbit in the Dynamic Orbit Determination Process

NASA Astrophysics Data System (ADS)

Bobojć, Andrzej; Drożyner, Andrzej; Rzepecka, Zofia

2017-04-01

The work includes the comparison of performance of selected geopotential models in the dynamic orbit estimation of the satellite of the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) mission. This was realized by fitting estimated orbital arcs to the official centimeter-accuracy GOCE kinematic orbit which is provided by the European Space Agency. The Cartesian coordinates of kinematic orbit were treated as observations in the orbit estimation. The initial satellite state vector components were corrected in an iterative process with respect to the J2000.0 inertial reference frame using the given geopotential model, the models describing the remaining gravitational perturbations and the solar radiation pressure. Taking the obtained solutions into account, the RMS values of orbital residuals were computed. These residuals result from the difference between the determined orbit and the reference one - the GOCE kinematic orbit. The performance of selected gravity models was also determined using various orbital arc lengths. Additionally, the RMS fit values were obtained for some gravity models truncated at given degree and order of spherical harmonic coefficients. The advantage of using the kinematic orbit is its independence from any a priori dynamical models. For the research such GOCE-independent gravity models as HUST-Grace2016s, ITU_GRACE16, ITSG-Grace2014s, ITSG-Grace2014k, GGM05S, Tongji-GRACE01, ULUX_CHAMP2013S, ITG-GRACE2010S, EIGEN-51C, EIGEN5S, EGM2008 and EGM96 were adopted.

Coalition Battle Management Language (C-BML) (Language de gestion du champ de bataille (C-BML)

DTIC Science & Technology

2012-02-01

de gestion du champ de bataille (C-BML)) NMSG-048 Final Report. This document...BML) (Langage de gestion du champ de bataille (C-BML)) NMSG-048 Final Report. This document contains information authorized by NATO RTA for...Technical Readiness Level (TRL) that is consistent with an operational deployment. ES - 2 RTO-TR-MSG-048 Langage de gestion du champ de

Comparisons Between TIME-GCM/MERRA Simulations and LEO Satellite Observations

NASA Astrophysics Data System (ADS)

Hagan, M. E.; Haeusler, K.; Forbes, J. M.; Zhang, X.; Doornbos, E.; Bruinsma, S.; Lu, G.

2014-12-01

We report on yearlong National Center for Atmospheric Research (NCAR) thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) simulations where we utilize the recently developed lower boundary condition based on 3-hourly MERRA (Modern-Era Retrospective Analysis for Research and Application) reanalysis data to account for tropospheric waves and tides propagating upward into the model domain. The solar and geomagnetic forcing is based on prevailing geophysical conditions. The simulations show a strong day-to-day variability in the upper thermospheric neutral temperature tidal fields, which is smoothed out quickly when averaging is applied over several days, e.g. up to 50% DE3 amplitude reduction for a 10-day average. This is an important result with respect to tidal diagnostics from satellite observations where averaging over multiple days is inevitable. In order to assess TIME-GCM performance we compare the simulations with measurements from the Gravity field and steady-state Ocean Circulation Explorer (GOCE), Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) satellites.

High-Latitude Neutral Mass Density Maxima

NASA Astrophysics Data System (ADS)

Huang, C. Y.; Huang, Y.; Su, Y.-J.; Huang, T.; Sutton, E. K.

2017-10-01

Recent studies have reported that thermospheric effects due to solar wind driving can be observed poleward of auroral latitudes. In these papers, the measured neutral mass density perturbations appear as narrow, localized maxima in the cusp and polar cap. They conclude that Joule heating below the spacecraft is the cause of the mass density increases, which are sometimes associated with local field-aligned current structures, but not always. In this paper we investigate neutral mass densities measured by accelerometers on the CHAllenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) spacecraft from launch until years 2010 (CHAMP) and 2012 (GRACE), approximately 10 years of observations from each satellite. We extract local maxima in neutral mass densities over the background using a smoothing window with size of one quarter of the orbit. The maxima have been analyzed for each year and also for the duration of each set of satellite observations. We show where they occur, under what solar wind conditions, and their relation to magnetic activity. The region with the highest frequency of occurrence coincides approximately with the cusp and mantle, with little direct evidence of an auroral zone source. Our conclusions agree with the "hot polar cap" observations that have been reported and studied in the past.

Time-Variable Gravity from Space: Quarter Century of Observations, Mysteries, and Prospects

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Boy, John-Paul

2003-01-01

Any large mass transport in the Earth system produces changes in the gravity field. Via the space geodetic technique of satellite-laser ranging in the last quarter century, the Earth's dynamic oblateness J2 (the lowest-degree harmonic component of the gravity field) has been observed to undergo a slight decrease -- until around 1998, when it switched quite suddenly to an increase trend which has continued to 2001 before sharply turning back to the value which it is "supposed to be"!. The secular decrease in J2 has long been attributed primarily to the post-glacial rebound in the mantle; the present increase signifies an even larger change in global mass distribution whose J2 effect overshadows that of the post-glacial rebound, at least over interannual timescales. Intriguing evidences have been found in the ocean water distribution, especially in the extratropical Pacific basins, that may be responsible for this J2 change. New techniques based on satellite-to-satellite tracking will yield greatly improved observations for time-variable gravity, with much higher precision and spatial resolution (i.e., much higher harmonic degrees). The most important example is the GRACE mission launched in March 2002, following the success of the CHAMP mission. Such observations are becoming a new and powerful tool for remote sensing of geophysical fluid processes that involve larger-scale mass transports.

Detection and identification of wild yeasts in Champús, a fermented Colombian maize beverage.

PubMed

Osorio-Cadavid, Esteban; Chaves-López, Clemencia; Tofalo, Rosanna; Paparella, Antonello; Suzzi, Giovanna

2008-09-01

The aim of this study was to identify and characterise the predominant yeasts in Champús, a traditional Colombian cereal-based beverage with a low alcoholic content. Samples of Champús from 20 production sites in the Cauca Valley region were analysed. A total of 235 yeast isolates were identified by conventional microbiological analyses and by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of ITS1-5.8S rDNA-ITS2. The dominant species were: Saccharomyces cerevisiae, Issatchenkia orientalis, Pichia fermentans, Pichia kluyveri var. kluyveri, Zygosaccharomyces fermentati, Torulospora delbruekii, Galactomyces geotrichum and Hanseniaspora spp. Model Champús systems were inoculated with single strains of some isolated sporogenus species and the aromatic profiles were analysed by SPME. Analysis of data showed that Champús strains produced high amounts of esters. The aromatic compounds produced by Saccharomyces and non-Saccharomyces yeasts from Champús can exert a relevant influence on the sensory characteristics of the fermented beverage. The Champús strains could thus represent an important source for new yeast biotypes with potential industrial applications.

De novo pathogenic variants in CHAMP1 are associated with global developmental delay, intellectual disability, and dysmorphic facial features.

PubMed

Tanaka, Akemi J; Cho, Megan T; Retterer, Kyle; Jones, Julie R; Nowak, Catherine; Douglas, Jessica; Jiang, Yong-Hui; McConkie-Rosell, Allyn; Schaefer, G Bradley; Kaylor, Julie; Rahman, Omar A; Telegrafi, Aida; Friedman, Bethany; Douglas, Ganka; Monaghan, Kristin G; Chung, Wendy K

2016-01-01

We identified five unrelated individuals with significant global developmental delay and intellectual disability (ID), dysmorphic facial features and frequent microcephaly, and de novo predicted loss-of-function variants in chromosome alignment maintaining phosphoprotein 1 (CHAMP1). Our findings are consistent with recently reported de novo mutations in CHAMP1 in five other individuals with similar features. CHAMP1 is a zinc finger protein involved in kinetochore-microtubule attachment and is required for regulating the proper alignment of chromosomes during metaphase in mitosis. Mutations in CHAMP1 may affect cell division and hence brain development and function, resulting in developmental delay and ID.

Effects Of HIV stigma reduction interventions in diasporic communities: insights from the CHAMP study.

PubMed

Li, Alan Tai-Wai; Fung, Kenneth Po-Lun; Maticka-Tyndale, Eleanor; Wong, Josephine Pui-Hing

2018-06-01

Racialized diasporic communities in Canada experience disproportionate burden of HIV infection. Their increased vulnerabilities are associated with interlocking challenges, including barriers in accessing resources, migration and settlement stress, and systemic exclusion. Further, people living with HIV (PLHIV) in these diasporic communities face stigma and discrimination in both mainstream Canadian society as well as their own ethno-racial communities. HIV stigma negatively impacts all aspects of HIV care, from testing to disclosure to treatment and ongoing care. In response to these challenges, a Toronto based community organization developed and implemented the CHAMP project to engage people living with HIV/AIDS (PLHIV) and leaders from different service sectors from the African/Caribbean, Asian and Latino communities to explore challenges and strategies to reduce HIV stigma and build community resilience. The study engaged 66 PLHIV and ethno-racial leaders from faith, media and social justice sectors in two stigma-reduction training programs: Acceptance Commitment Therapy Training (ACT) and Social Justice Capacity Building (SJCB). Data collection included pre-and post- intervention surveys, focus groups and monthly activity logs. Participants were followed for a year and data on changes in the participants' attitudes and behaviors as well as their actual engagement in HIV prevention, PLHIV support and stigma reduction activities were collected. CHAMP results showed that the interventions were effective in reducing HIV stigma and increasing participants' readiness to take action towards positive social change. Participants' activity logs over a period of 9 months after completing the training showed they had engaged in 1090 championship activities to advocate for HIV related health equity and social justice issues affecting racialized and newcomer PLHIV and communities.

A Ball Skills Intervention in Preschoolers: The CHAMP Randomized Controlled Trial.

PubMed

Robinson, Leah E; Veldman, Sanne L C; Palmer, Kara K; Okely, Anthony D

2017-11-01

Fundamental motor skills (FMS) contribute to positive health trajectories. A high level of competence in ball skills (a subset of FMS) is a predictor for time spent in moderate- to vigorous-intensity physical activity during adolescence. This study examined the effects of a ball skills intervention on ball skill competence among preschool-aged boys and girls. This is a two-armed randomized controlled trial. A total of 124 preschoolers (Mage ± SD = 48.14 ± 6.62 months) were randomly assigned to one of two groups, the Children's Health Activity Motor Program (CHAMP; n = 81) or control (n = 43). FMS were measured before, after (9 wk), and at retention (18 wk) using the object control subscale of the Test of Gross Motor Development, Second Edition. Changes in ball skill scores were calculated (pretest-posttest, pretest-retention, posttest-retention) and were compared using one-way ANOVAs with post hoc Scheffe analysis. Findings support that groups demonstrated significantly different rates of change from pretest to posttest (F3,117 = 179.45, P < 0.001), pretest to retention (F3,113 = 95.8, P < 0.001), and posttest to retention (F3,113 = 189.89, P < 0.001). Compared with their control group peers, CHAMP boys and girls had greater positive rates of change from pretest to posttest and pretest to retention as well as greater negative rates of change from posttest to retention. CHAMP was effective in improving and maintaining ball skills in preschool-age boys and girls. Findings support that providing a high-quality motor skill program in early childhood settings could potentially be a sustainable public health approach to promoting FMS and positive developmental trajectories for health.

CHAMP (Camera, Handlens, and Microscope Probe)

NASA Technical Reports Server (NTRS)

Mungas, Greg S.; Boynton, John E.; Balzer, Mark A.; Beegle, Luther; Sobel, Harold R.; Fisher, Ted; Klein, Dan; Deans, Matthew; Lee, Pascal; Sepulveda, Cesar A.

2005-01-01

CHAMP (Camera, Handlens And Microscope Probe)is a novel field microscope capable of color imaging with continuously variable spatial resolution from infinity imaging down to diffraction-limited microscopy (3 micron/pixel). As a robotic arm-mounted imager, CHAMP supports stereo imaging with variable baselines, can continuously image targets at an increasing magnification during an arm approach, can provide precision rangefinding estimates to targets, and can accommodate microscopic imaging of rough surfaces through a image filtering process called z-stacking. CHAMP was originally developed through the Mars Instrument Development Program (MIDP) in support of robotic field investigations, but may also find application in new areas such as robotic in-orbit servicing and maintenance operations associated with spacecraft and human operations. We overview CHAMP'S instrument performance and basic design considerations below.

Estimating Density Using Precision Satellite Orbits from Multiple Satellites

NASA Astrophysics Data System (ADS)

McLaughlin, Craig A.; Lechtenberg, Travis; Fattig, Eric; Krishna, Dhaval Mysore

2012-06-01

This article examines atmospheric densities estimated using precision orbit ephemerides (POE) from several satellites including CHAMP, GRACE, and TerraSAR-X. The results of the calibration of atmospheric densities along the CHAMP and GRACE-A orbits derived using POEs with those derived using accelerometers are compared for various levels of solar and geomagnetic activity to examine the consistency in calibration between the two satellites. Densities from CHAMP and GRACE are compared when GRACE is orbiting nearly directly above CHAMP. In addition, the densities derived simultaneously from CHAMP, GRACE-A, and TerraSAR-X are compared to the Jacchia 1971 and NRLMSISE-00 model densities to observe altitude effects and consistency in the offsets from the empirical models among all three satellites.

Internal consistency of the CHAMPS physical activity questionnaire for Spanish speaking older adults.

PubMed

Rosario, Martín G; Vázquez, Jenniffer M; Cruz, Wanda I; Ortiz, Alexis

2008-09-01

The Community Healthy Activities Model Program for Seniors (CHAMPS) is a physical activity monitoring questionnaire for people between 65 to 90 years old. This questionnaire has been previously translated to Spanish to be used in the Latin American population. To adapt the Spanish version of the CHAMPS questionnaire to Puerto Rico and assess its internal consistency. An external review committee adapted the existent Spanish version of the CHAMPS to be used in the Puerto Rican population. Three older adults participated in a second phase with the purpose of training the research team. After the second phase, 35 older adults participated in a third content adaptation phase. During the third phase, the preliminary Spanish version for Puerto Rico of the CHAMPS was given to the 35 participants to assess for clarity, vocabulary and understandability. Interviews to each participant in the third phase were carried out to obtain feedback and create a final Spanish version of the CHAMPS for Puerto Rico. After analyses of this phase, the external review committee prepared a final Spanish version of the CHAMPS for Puerto Rico. The final version was administered to 15 older adults (76 +/- 6.5 years) to assess the internal consistency by using Cronbach's Alpha analysis. The questionnaire showed a strong internal consistency of 0.76. The total time to answer the questionnaire was 17.4 minutes. The Spanish version of the CHAMPS questionnaire for Puerto Rico suggested being an easy to administer and consistent measurement tool to assess physical activity in older adults.

An Evaluation of CHAMPS: A Classroom Management Program

ERIC Educational Resources Information Center

Minnear, Holly J.

2015-01-01

This dissertation was designed to examine the impact of Conversation, Help, Activity, Movement, Participation, Success (CHAMPS), a classroom management program in elementary schools in a district in North Carolina. The participants included principals and teachers who attended a 2-day training course and implemented the CHAMPS program at their…

2010 Coalition Battle Management Language Workshop (Atelier 2010 sur le langage de gestion du champ de bataille pour les operations en coalition)

DTIC Science & Technology

2010-02-01

Feb 2010 2010 Coalition Battle Management Language Workshop (Atelier 2010 sur le langage de gestion du champ de bataille pour les opérations en...RTO MEETING PROCEEDINGS MP-MSG-079 2010 Coalition Battle Management Language Workshop (Atelier 2010 sur le langage de gestion du champ de ...RTO-MP-MSG-079 ES - 3 Atelier 2010 sur le langage de gestion du champ de bataille pour les opérations en coalition (RTO-MP-MSG-079

Family-based HIV prevention and intervention services for youth living in poverty-affected contexts: the CHAMP model of collaborative, evidence-informed programme development

PubMed Central

2010-01-01

Family-based interventions with children who are affected by HIV and AIDS are not well established. The Collaborative HIV Prevention and Adolescent Mental Health Program (CHAMP) represents one of the few evidence-based interventions tested in low-income contexts in the US, Caribbean and South Africa. This paper provides a description of the theoretical and empirical bases of the development and implementation of CHAMP in two of these countries, the US and South Africa. In addition, with the advent of increasing numbers of children infected with HIV surviving into adolescence and young adulthood, a CHAMP+ family-based intervention, using the founding principles of CHAMP, has been developed to mitigate the risk influences associated with being HIV positive. PMID:20573290

What have we gained from GOCE, and what is still to be expected?

NASA Astrophysics Data System (ADS)

Pail, R.; Fecher, T.; Mayer-Gürr, T.; Rieser, D.; Schuh, W. D.; Brockmann, J. M.; Jäggi, A.; Höck, E.

2012-04-01

So far three releases of GOCE-only gravity field models applying the time-wise method have been computed in the frame of the ESA project "GOCE High-Level Processing Facility". They have been complemented by satellite-only combination models generated by the GOCO ("Gravity Observation Combination") consortium. Due to the fact that the processing strategy has remained practically unchanged for all releases, the continuous improvement by including more and more GOCE data can be analyzed. One of the basic features of the time-wise gravity field models (GOCE_TIM) is the fact, that no gravity field prior information is used, neither as reference model nor for constraining the solution. Therefore, the gain of knowledge on the Earth's gravity field derived purely from the GOCE mission can be evaluated. The idea of the complementary GOCO models is to improve the long to medium wavelengths of the gravity field solutions, which are rather weakly defined by GOCE orbit information, by inclusion of additional data from satellite sources such as GRACE, CHAMP and SLR, taking benefit from the individual strengths and favourable features of the individual data types. In this contribution, we will review which impact GOCE has achieved so far on global and regional gravity field modelling. Besides the gravity field modelling itself, the contributions of GOCE to several application fields, such as the computation of geodetic mean dynamic topography (MDT), and also for geophysical modelling of the lithosphere, will be highlighted. Special emphasis shall be given to the discussion to what extent the full variance-covariance information, representing very realistic error estimates of the gravity field accuracy, can be utilized. Finally, also a GOCE performance prediction shall be given. After the end of the extended mission phase by December 2012, currently several mission scenarios are discussed, such as either extending the mission period further as long as possible at the same altitude, or lowering the satellite by 10-20 km for a shorter period. Based on numerical simulation studies the pros and cons of several scenarios regarding the achievable gravity field accuracy shall be evaluated and quantified.

Camera, Hand Lens, and Microscope Probe (CHAMP): An Instrument Proposed for the 2009 MSL Rover Mission

NASA Technical Reports Server (NTRS)

Mungas, Greg S.; Beegle, Luther W.; Boynton, John E.; Lee, Pascal; Shidemantle, Ritch; Fisher, Ted

2004-01-01

The Camera, Hand Lens, and Microscope Probe (CHAMP) will allow examination of martian surface features and materials (terrain, rocks, soils, samples) on spatial scales ranging from kilometers to micrometers, thus enabling both microscopy and context imaging with high operational flexibility. CHAMP is designed to allow the detailed and quantitative investigation of a wide range of geologic features and processes on Mars, leading to a better quantitative understanding of the evolution of the martian surface environment through time. In particular, CHAMP will provide key data that will help understand the local region explored by Mars Surface Laboratory (MSL) as a potential habitat for life. CHAMP will also support other anticipated MSL investigations, in particular by helping identify and select the highest priority targets for sample collection and analysis by the MSL's analytical suite.

The development and implementation of theory-driven programs capable of addressing poverty-impacted children's health, mental health, and prevention needs: CHAMP and CHAMP+, evidence-informed, family-based interventions to address HIV risk and care.

PubMed

McKernan McKay, Mary; Alicea, Stacey; Elwyn, Laura; McClain, Zachary R B; Parker, Gary; Small, Latoya A; Mellins, Claude Ann

2014-01-01

This article describes a program of prevention and intervention research conducted by the CHAMP (Collaborative HIV prevention and Adolescent Mental health Project; McKay & Paikoff, 2007 ) investigative team. CHAMP refers to a set of theory-driven, evidence-informed, collaboratively designed, family-based approaches meant to address the prevention, health, and mental health needs of poverty-impacted African American and Latino urban youth who are either at risk for HIV exposure or perinatally infected and at high risk for reinfection and possible transmission. CHAMP approaches are informed by theoretical frameworks that incorporate an understanding of the critical influences of multilevel contextual factors on youth risk taking and engagement in protective health behaviors. Highly influential theories include the triadic theory of influence, social action theory, and ecological developmental perspectives. CHAMP program delivery strategies were developed via a highly collaborative process drawing upon community-based participatory research methods in order to enhance cultural and contextual sensitivity of program content and format. The development and preliminary outcomes associated with a family-based intervention for a new population, perinatally HIV-infected youth and their adult caregivers, referred to as CHAMP+, is described to illustrate the integration of theory, existing evidence, and intensive input from consumers and healthcare providers.

Synthese de champs sonores adaptative

NASA Astrophysics Data System (ADS)

Gauthier, Philippe-Aubert

La reproduction de champs acoustiques est une approche physique au probleme technologique de la spatialisation sonore. Cette these concerne l'aspect physique de la reproduction de champs acoustiques. L'objectif principal est l'amelioration de la reproduction de champs acoustiques par "synthese de champs acoustiques" ("Wave Field Synthesis", WFS), une approche connue, basee sur des hypotheses de champ libre, a l'aide du controle actif par l'ajout de capteurs de l'erreur de reproduction et d'une boucle fermee. Un premier chapitre technique (chapitre 4) expose les resultats d'appreciation objective de la WFS par simulations et mesures experimentales. L'effet indesirable de la salle de reproduction sur les qualites objectives de la WFS fut illustre. Une premiere question de recherche fut ensuite abordee (chapitre 5), a savoir s'il est possible de reproduire des champs progressifs en salle dans un paradigme physique de controle actif: cette possibilite fut prouvee. L'approche technique privilegiee, "synthese de champs adaptative" ("Adaptive Wave Field Synthesis" [AWFS]), fut definie, puis simulee (chapitre 6). Cette approche d'AWFS comporte une originalite en controle actif et en reproduction de champs acoustiques: la fonction cout quadratique representant la minimisation des erreurs de reproduction inclut une regularisation de Tikhonov avec solution a priori qui vient de la WFS. L'etude de l'AWFS a l'aide de la decomposition en valeurs singulieres (chapitre 7) a permis de comprendre les mecanismes propres a l'AWFS. C'est la deuxieme principale originalite de la these. L'algorithme FXLMS (LMS et reference filtree) est modifie pour l'AWFS (chapitre 8). Le decouplage du systeme par decomposition en valeurs singulieres est illustre dans le domaine du traitement de signal et l'AWFS basee sur le controle independant des modes de rayonnement est simulee (chapitre 8). Ce qui constitue la troisieme originalite principale de cette these. Ces simulations du traitement de signal montrent l'efficacite des algorithmes et la capacite de l'AWFS a attenuer les erreurs attribuables a des reflexions acoustiques. Le neuvieme chapitre presente des resultats experimentaux d'AWFS. L'objectif etait de valider la methode et d'evaluer les performances de l'AWFS. Un autre algorithme prometteur est aussi teste. Les resultats demontrent la bonne marche de l'AWFS et des algorithmes testes. Autant dans le cas de la reproduction de champs harmoniques que dans le cas de la reproduction de champs a large bande, l'AWFS reduit l'erreur de reproduction de la WFS et les effets indesirables causes par les lieux de reproduction.

Quasi-biennial Oscillations (QBO) as seen in GPS/CHAMP Tropospheric and Ionospheric Data

NASA Technical Reports Server (NTRS)

Wu, Dong L.; Pi, Xiaoqing; Ao, Chi O.; Mannucci, Anthony J.

2006-01-01

A viewgraph presentation on Quasi-biennial Oscillations (QBO) from Global Positioning System/Challenging Mini-Satellite Payload (GPS/CHAMP) tropospheric and ionsopheric data is shown. The topics include: 1) A brief review of QBO; 2) Characteristics of small-scale oscillations in GPS/CHAMP 50-Hz raw measurements; 3) Variations of lower atmospheric variances; and 4) Variations of E-region variances.

DTU candidate field models for IGRF-12 and the CHAOS-5 geomagnetic field model

NASA Astrophysics Data System (ADS)

Finlay, Christopher C.; Olsen, Nils; Tøffner-Clausen, Lars

2015-07-01

We present DTU's candidate field models for IGRF-12 and the parent field model from which they were derived, CHAOS-5. Ten months of magnetic field observations from ESA's Swarm mission, together with up-to-date ground observatory monthly means, were used to supplement the data sources previously used to construct CHAOS-4. The internal field part of CHAOS-5, from which our IGRF-12 candidate models were extracted, is time-dependent up to spherical harmonic degree 20 and involves sixth-order splines with a 0.5 year knot spacing. In CHAOS-5, compared with CHAOS-4, we update only the low-degree internal field model (degrees 1 to 24) and the associated external field model. The high-degree internal field (degrees 25 to 90) is taken from the same model CHAOS-4h, based on low-altitude CHAMP data, which was used in CHAOS-4. We find that CHAOS-5 is able to consistently fit magnetic field data from six independent low Earth orbit satellites: Ørsted, CHAMP, SAC-C and the three Swarm satellites (A, B and C). It also adequately describes the secular variation measured at ground observatories. CHAOS-5 thus contributes to an initial validation of the quality of the Swarm magnetic data, in particular demonstrating that Huber weighted rms model residuals to Swarm vector field data are lower than those to Ørsted and CHAMP vector data (when either one or two star cameras were operating). CHAOS-5 shows three pulses of secular acceleration at the core surface over the past decade; the 2006 and 2009 pulses have previously been documented, but the 2013 pulse has only recently been identified. The spatial signature of the 2013 pulse at the core surface, under the Atlantic sector where it is strongest, is well correlated with the 2006 pulse, but anti-correlated with the 2009 pulse.

Time-Variable Gravity from Satellite-Laser-Ranging and Doppler Measurements: An Update on the Low-degree components as well as the connections with Geophysical/Climatic Processes

NASA Technical Reports Server (NTRS)

Cox, Christopher M.; Chao, Benjamin F.; Au, Andrew Y.; Boy, J.-P.

2003-01-01

The oblateness of the Earth's gravity field, 52, has long been observed to undergo a slight decrease due to post-glacial rebound of the mantle. Sometime around 1998 this trend reversed quite suddenly. This reversal persisted until 2001, at which point the atmosphere-corrected time series appears to have reversed yet again. Presently, the time series appears to be returning to the value that would nominally have been reached had the anomaly not occurred. This anomaly signifies a large interannual change in global mass distribution whose J2 effect overshadows that of the post-glacial rebound over such timescales. A number of possible causes have been considered, with oceanic mass redistribution as the leading candidate although other effects, such as glacial melting and core effects may be contributing. The amount by which J2 returns to it's nominal value provides a valuable constraint on the separation of the causes, and will be considered. We will present our latest Satellite Laser Ranging and DORIS Doppler derived time series for J2, and various other low-degree harmonic terms, as well as our investigations into the causes. In addition, we will show the comparison of the J2 results with those derived from CHAMP, as computed at NASA GSFC, and the recently released GRACE gravity model.

The global distribution of gravity wave energy in the lower stratosphere derived from GPS data and gravity wave modelling: Attempt and challenges

NASA Astrophysics Data System (ADS)

Fröhlich, K.; Schmidt, T.; Ern, M.; Preusse, P.; de La Torre, A.; Wickert, J.; Jacobi, Ch.

2007-12-01

Five years of global temperatures retrieved from radio occultations measured by Champ (Challenging Minisatellite Payload) and SAC-C (Satelite de Aplicaciones Cientificas-C) are analyzed for gravity waves (GWs). In order to separate GWs from other atmospheric variations, a high-pass filter was applied on the vertical profile. Resulting temperature fluctuations correspond to vertical wavelengths between 400 m (instrumental resolution) and 10 km (limit of the high-pass filter). The temperature fluctuations can be converted into GW potential energy, but for comparison with parameterization schemes GW momentum flux is required. We therefore used representative values for the vertical and horizontal wavelength to infer GW momentum flux from the GPS measurements. The vertical wavelength value is determined by high-pass filtering, the horizontal wavelength is adopted from a latitude-dependent climatology. The obtained momentum flux distributions agree well, both in global distribution and in absolute values, with simulations using the Warner and McIntyre parameterization (WM) scheme. However, discrepancies are found in the annual cycle. Online simulations, implementing the WM scheme in the mechanistic COMMA-LIM (Cologne Model of the Middle Atmosphere—Leipzig Institute for Meteorology) general circulation model (GCM), do not converge, demonstrating that a good representation of GWs in a GCM requires both a realistic launch distribution and an adequate representation of GW breaking and momentum transfer.

Scale Sizes of High-Latitude Neutral Mass Density Perturbations

NASA Astrophysics Data System (ADS)

Huang, C. Y.; Huang, Y.; Su, Y. J.; Huang, T.; Sutton, E. K.

2017-12-01

In a statistical study of neutral mass density maxima, we found for a select interval, that 57% of the maxima have correlated field-aligned current (FAC) signatures, indicative of localized Ohmic heating. However the remaining 43% do not, and we suggested that these maxima may be due to gravity waves generated by neutral heating. We follow up on this study by an investigation into the spatial scale sizes of the mass density maxima using high-resolution neutral density and FAC data from CHAMP, when the satellite is in conjunction with DMSP, which provides the corresponding ion drift velocity, particle precipitation and Poynting flux. The study shows the average scale sizes of the perturbations due to J x B heating, as well as the sizes of the waves generated by Joule heating.

Evaluation of Gravitational Field Models Based on the Laser Range Observation of Low Earth Orbit Satellites

NASA Astrophysics Data System (ADS)

Hong-bo, Wang; Chang-yin, Zhao; Wei, Zhang; Jin-wei, Zhan; Sheng-xian, Yu

2016-07-01

The Earth gravitational field model is one of the most important dynamic models in satellite orbit computation. Several space gravity missions made great successes in recent years, prompting the publishing of several gravitational filed models. In this paper, two classical (JGM3, EGM96) and four latest (EIGEN-CHAMP05S, GGM03S, GOCE02S, EGM2008) models are evaluated by employing them in the precision orbit determination (POD) and prediction. These calculations are performed based on the laser ranging observation of four Low Earth Orbit (LEO) satellites, including CHAMP, GFZ-1, GRACE-A, and SWARM-A. The residual error of observation in POD is adopted to describe the accuracy of six gravitational field models. The main results we obtained are as follows. (1) For the POD of LEOs, the accuracies of 4 latest models are at the same level, and better than those of 2 classical models; (2) Taking JGM3 as reference, EGM96 model's accuracy is better in most situations, and the accuracies of the 4 latest models are improved by 12%-47% in POD and 63% in prediction, respectively. We also confirm that the model's accuracy in POD is enhanced with the increasing degree and order if they are smaller than 70, and when they exceed 70, the accuracy keeps constant, implying that the model's degree and order truncated to 70 are sufficient to meet the requirement of LEO computation of centimeter precision.

Multiscale Materials Science: A Mathematical Approach to the Role of Defects and Uncertainty

DTIC Science & Technology

2015-03-01

ADDRESS(ES) Ecole Nationale des Ponts et Chaussees 6 et 8 avenue Blaise Pascal, Cite Descartes , Champs sur Marne 77 455 Marne la Vallee Cedex 2...nationale des ponts et chaussees 6 et 8 avenue Blaise-Pascal, Cite Descartes Champs-sur-Marne F-77455 Mame-la-Vallee cedex 2 www.enpc.fr tel...CHAUSSEES 6, AVENUE BLAISE PASCAL 6 ET 8 CITE DESCARTES CHAMPS SUR MARNE, 77420 FR 13d. BUSINESS OFFICE CONTACT: CAROLINA GARCIA-OLMEDO 13e

Antoine Béchamp: pere de la biologie. Oui ou non?

PubMed

Manchester, K L

2001-06-01

There is an alternative medicine lobby that, in conjunction with antivivisectionists, believes Louis Pasteur to have been a fraud [R. Bottomley's You Don't Have to Feel Unwell! (Newleaf, 1994) is a recent example]. They frame their accusations around a rivalry between Pasteur and a contemporary, Antoine Béchamp, from whom they suggest Pasteur stole his ideas and then distorted them for his own purposes. This article explores some aspects of the controversies between Béchamp and Pasteur.

Constellations of Next Generation Gravity Missions: Simulations regarding optimal orbits and mitigation of aliasing errors

NASA Astrophysics Data System (ADS)

Hauk, M.; Pail, R.; Gruber, T.; Purkhauser, A.

2017-12-01

The CHAMP and GRACE missions have demonstrated the tremendous potential for observing mass changes in the Earth system from space. In order to fulfil future user needs a monitoring of mass distribution and mass transport with higher spatial and temporal resolution is required. This can be achieved by a Bender-type Next Generation Gravity Mission (NGGM) consisting of a constellation of satellite pairs flying in (near-)polar and inclined orbits, respectively. For these satellite pairs the observation concept of the GRACE Follow-on mission with a laser-based low-low satellite-to-satellite tracking (ll-SST) system and more precise accelerometers and state-of-the-art star trackers is adopted. By choosing optimal orbit constellations for these satellite pairs high frequency mass variations will be observable and temporal aliasing errors from under-sampling will not be the limiting factor anymore. As part of the European Space Agency (ESA) study "ADDCON" (ADDitional CONstellation and Scientific Analysis Studies of the Next Generation Gravity Mission) a variety of mission design parameters for such constellations are investigated by full numerical simulations. These simulations aim at investigating the impact of several orbit design choices and at the mitigation of aliasing errors in the gravity field retrieval by co-parametrization for various constellations of Bender-type NGGMs. Choices for orbit design parameters such as altitude profiles during mission lifetime, length of retrieval period, value of sub-cycles and choice of prograde versus retrograde orbits are investigated as well. Results of these simulations are presented and optimal constellations for NGGM's are identified. Finally, a short outlook towards new geophysical applications like a near real time service for hydrology is given.

Coordinating with Humans by Adjustable-Autonomy for Multirobot Pursuit (CHAMP)

NASA Astrophysics Data System (ADS)

Dumond, Danielle; Ayers, Jeanine; Schurr, Nathan; Carlin, Alan; Burke, Dustin; Rousseau, Jeffrey

2012-06-01

One of the primary challenges facing the modern small-unit tactical team is the ability of the unit to safely and effectively search, explore, clear and hold urbanized terrain that includes buildings, streets, and subterranean dwellings. Buildings provide cover and concealment to an enemy and restrict the movement of forces while diminishing their ability to engage the adversary. The use of robots has significant potential to reduce the risk to tactical teams and dramatically force multiply the small unit's footprint. Despite advances in robotic mobility, sensing capabilities, and human-robot interaction, the use of robots in room clearing operations remains nascent. CHAMP is a software system in development that integrates with a team of robotic platforms to enable them to coordinate with a human operator performing a search and pursuit task. In this way, the human operator can either give control to the robots to search autonomously, or can retain control and direct the robots where needed. CHAMP's autonomy is built upon a combination of adversarial pursuit algorithms and dynamic function allocation strategies that maximize the team's resources. Multi-modal interaction with CHAMP is achieved using novel gesture-recognition based capabilities to reduce the need for heads-down tele-operation. The Champ Coordination Algorithm addresses dynamic and limited team sizes, generates a novel map of the area, and takes into account mission goals, user preferences and team roles. In this paper we show results from preliminary simulated experiments and find that the CHAMP system performs faster than traditional search and pursuit algorithms.

Simulation study on combination of GRACE monthly gravity field solutions

NASA Astrophysics Data System (ADS)

Jean, Yoomin; Meyer, Ulrich; Jäggi, Adrian

2016-04-01

The GRACE monthly gravity fields from different processing centers are combined in the frame of the project EGSIEM. This combination is done on solution level first to define weights which will be used for a combination on normal equation level. The applied weights are based on the deviation of the individual gravity fields from the arithmetic mean of all involved gravity fields. This kind of weighting scheme relies on the assumption that the true gravity field is close to the arithmetic mean of the involved individual gravity fields. However, the arithmetic mean can be affected by systematic errors in individual gravity fields, which consequently results in inappropriate weights. For the future operational scientific combination service of GRACE monthly gravity fields, it is necessary to examine the validity of the weighting scheme also in possible extreme cases. To investigate this, we make a simulation study on the combination of gravity fields. Firstly, we show how a deviated gravity field can affect the combined solution in terms of signal and noise in the spatial domain. We also show the impact of systematic errors in individual gravity fields on the resulting combined solution. Then, we investigate whether the weighting scheme still works in the presence of outliers. The result of this simulation study will be useful to understand and validate the weighting scheme applied to the combination of the monthly gravity fields.

CHAMP - Camera, Handlens, and Microscope Probe

NASA Technical Reports Server (NTRS)

Mungas, G. S.; Beegle, L. W.; Boynton, J.; Sepulveda, C. A.; Balzer, M. A.; Sobel, H. R.; Fisher, T. A.; Deans, M.; Lee, P.

2005-01-01

CHAMP (Camera, Handlens And Microscope Probe) is a novel field microscope capable of color imaging with continuously variable spatial resolution from infinity imaging down to diffraction-limited microscopy (3 micron/pixel). As an arm-mounted imager, CHAMP supports stereo-imaging with variable baselines, can continuously image targets at an increasing magnification during an arm approach, can provide precision range-finding estimates to targets, and can accommodate microscopic imaging of rough surfaces through a image filtering process called z-stacking. Currently designed with a filter wheel with 4 different filters, so that color and black and white images can be obtained over the entire Field-of-View, future designs will increase the number of filter positions to include 8 different filters. Finally, CHAMP incorporates controlled white and UV illumination so that images can be obtained regardless of sun position, and any potential fluorescent species can be identified so the most astrobiologically interesting samples can be identified.

Reliability and Validity of 2 Self-Report Measures to Assess Sedentary Behavior in Older Adults.

PubMed

Gennuso, Keith P; Matthews, Charles E; Colbert, Lisa H

2015-05-01

The purpose of this study was to examine the reliability and validity of 2 currently available physical activity surveys for assessing time spent in sedentary behavior (SB) in older adults. Fifty-eight adults (≥65 years) completed the Yale Physical Activity Survey for Older Adults (YPAS) and Community Health Activities Model Program for Seniors (CHAMPS) before and after a 10-day period during which they wore an ActiGraph accelerometer (ACC). Intraclass correlation coefficients (ICC) examined test-retest reliability. Overall percent agreement and a kappa statistic examined YPAS validity. Lin's concordance correlation, Pearson correlation, and Bland-Altman analysis examined CHAMPS validity. Both surveys had moderate test-retest reliability (ICC: YPAS = 0.59 (P < .001), CHAMPS = 0.64 (P < .001)) and significantly underestimated SB time. Agreement between YPAS and ACC was low (κ = -0.0003); however, there was a linear increase (P < .01) in ACC-derived SB time across YPAS response categories. There was poor agreement between ACC-derived SB and CHAMPS (Lin's r = .005; 95% CI, -0.010 to 0.020), and no linear trend across CHAMPS quartiles (P = .53). Neither of the surveys should be used as the sole measure of SB in a study; though the YPAS has the ability to rank individuals, providing it with some merit for use in correlational SB research.

EGSIEM: Combination of GRACE monthly gravity models on normal equation level

NASA Astrophysics Data System (ADS)

Meyer, Ulrich; Jean, Yoomin; Jäggi, Adrian; Mayer-Gürr, Torsten; Neumayer, Hans; Lemoine, Jean-Michel

2016-04-01

One of the three geodetic services to be realized in the frame of the EGSIEM project is a scientific combination service. Each associated processing center (AC) will follow a set of common processing standards but will apply its own, independent analysis method. Therefore the quality, robustness and reliability of the combined monthly gravity fields is expected to improve significantly compared to the individual solutions. The Monthly GRACE gravity fields of all ACs are combined on normal equation level. The individual normal equations are weighted depending on pairwise comparisons of the individual gravity field solutions. To derive these weights and for quality control of the individual contributions first a combination of the monthly gravity fields on solution level is performed. The concept of weighting and of the combination on normal equation level is introduced and the formats used for normal equation exchange and gravity field solutions is described. First results of the combination on normal equation level are presented and compared to the corresponding combinations on solution level. EGSIEM has an open data policy and all processing centers of GRACE gravity fields are invited to participate in the combination.

Turning education into action: Impact of a collective social education approach to improve nurses' ability to recognize and accurately assess delirium in hospitalized older patients.

PubMed

Travers, Catherine; Henderson, Amanda; Graham, Fred; Beattie, Elizabeth

2018-03-01

Although cognitive impairment including dementia and delirium is common in older hospital patients, it is not well recognized or managed by hospital staff, potentially resulting in adverse events. This paper describes, and reports on the impact of a collective social education approach to improving both nurses' knowledge of, and screening for delirium. Thirty-four experienced nurses from six hospital wards, became Cognition Champions (CogChamps) to lead their wards in a collective social education process about cognitive impairment and the assessment of delirium. At the outset, the CogChamps were provided with comprehensive education about dementia and delirium from a multidisciplinary team of clinicians. Their knowledge was assessed to ascertain they had the requisite understanding to engage in education as a collective social process, namely, with each other and their local teams. Following this, they developed ward specific Action Plans in collaboration with their teams aimed at educating and evaluating ward nurses' ability to accurately assess and care for patients for delirium. The plans were implemented over five months. The broader nursing teams' knowledge was assessed, together with their ability to accurately assess patients for delirium. Each ward implemented their Action Plan to varying degrees and key achievements included the education of a majority of ward nurses about delirium and the certification of the majority as competent to assess patients for delirium using the Confusion Assessment Method. Two wards collected pre-and post-audit data that demonstrated a substantial improvement in delirium screening rates. The education process led by CogChamps and supported by educators and clinical experts provides an example of successfully educating nurses about delirium and improving screening rates of patients for delirium. ACTRN 12617000563369. Copyright © 2018 Elsevier Ltd. All rights reserved.

Magnetic Ripples Observed by Low-altitude Satellites and their Relation to Micro-barometric and Ground Magnetic Variations

NASA Astrophysics Data System (ADS)

Iyemori, T.; Aoyama, T.; Nakanishi, K.; Odagi, Y.; Sanoo, Y.; Yokoyama, Y.; Yamada, A.

2017-12-01

The `magnetic ripples' are small scale magnetic fluctuations observed in upper ionosphere by low altitude satellites such as CHAMP or Swarm, and they are spatial structure of field-aligned currents along satellite orbit. They are observed almost always in mid- and low-latitudes. From their geographical and seasonal characteristics, they are supposed to be caused by the atmospheric waves which propagates from lower atmosphere to the ionosphere. Although the global distribution and its local time or seasonal variation of the amplitude of magnetic ripples, or the correlation with meteorological phenomena such as typhoons strongly suggest the cumulus convection as the main origin, we need to clarify which mode of atmospheric waves, i.e., acoustic wave or internal gravity wave, mainly contributes to the magnetic ripples and what meteorological condition correspond them. For those purposes, we analyze ground based magnetic and micro-barometric variations. We try to make quantitative estimation of the contribution from both acoustic and internal mode of gravity waves, acoustic resonance, etc. by calculating PSD (power spectral density) of pressure and ground magnetic variations. In this paper, we present their basic characteristics and discuss the relation with magnetic ripples. [Acknowledgments]: The ground observations have been supported by many people including students at our graduate school and by the collaboration with other institutions.

An Evaluation of CHAMPS for Classroom Management

ERIC Educational Resources Information Center

Evans, Vernessa

2016-01-01

Teacher education programs focus on preparing teachers to instruct students, but they usually do not focus on preparing teachers to manage students' behavior, which may prevent teachers from providing effective instruction. This project study evaluated a classroom behavior management model, CHAMPS, designed to help teachers manage student behavior…

Reliability and Validity of Two Self-report Measures to Assess Sedentary Behavior in Older Adults

PubMed Central

Gennuso, Keith P.; Matthews, Charles E.; Colbert, Lisa H.

2015-01-01

Background The purpose of this study was to examine the reliability and validity of two currently available physical activity surveys for assessing time spent in sedentary behavior (SB) in older adults. Methods Fifty-eight adults (≥65 years) completed the Yale Physical Activity Survey for Older Adults (YPAS) and Community Health Activities Model Program for Seniors (CHAMPS) before and after a 10-day period during which they wore an ActiGraph accelerometer (ACC). Intraclass correlation coefficients (ICC) examined test-retest reliability. Overall percent agreement and a kappa statistic examined YPAS validity. Lin’s concordance correlation, Pearson correlation, and Bland-Altman analysis examined CHAMPS validity. Results Both surveys had moderate test-retest reliability (ICC: YPAS=0.59 (P<0.001), CHAMPS=0.64 (P<0.001)) and significantly underestimated SB time. Agreement between YPAS and ACC was low (κ=−0.0003); however, there was a linear increase (P< 0.01) in ACC-derived SB time across YPAS response categories. There was poor agreement between ACC-derived SB and CHAMPS (Lin’s r=0.005; 95% CI, −0.010 to 0.020), and no linear trend across CHAMPS quartiles (p=0.53). Conclusions Neither of the surveys should be used as the sole measure of SB in a study; though the YPAS has the ability to rank individuals, providing it with some merit for use in correlational SB research. PMID:25110344

Precision Orbit Derived Atmospheric Density: Development and Performance

NASA Astrophysics Data System (ADS)

McLaughlin, C.; Hiatt, A.; Lechtenberg, T.; Fattig, E.; Mehta, P.

2012-09-01

Precision orbit ephemerides (POE) are used to estimate atmospheric density along the orbits of CHAMP (Challenging Minisatellite Payload) and GRACE (Gravity Recovery and Climate Experiment). The densities are calibrated against accelerometer derived densities and considering ballistic coefficient estimation results. The 14-hour density solutions are stitched together using a linear weighted blending technique to obtain continuous solutions over the entire mission life of CHAMP and through 2011 for GRACE. POE derived densities outperform the High Accuracy Satellite Drag Model (HASDM), Jacchia 71 model, and NRLMSISE-2000 model densities when comparing cross correlation and RMS with accelerometer derived densities. Drag is the largest error source for estimating and predicting orbits for low Earth orbit satellites. This is one of the major areas that should be addressed to improve overall space surveillance capabilities; in particular, catalog maintenance. Generally, density is the largest error source in satellite drag calculations and current empirical density models such as Jacchia 71 and NRLMSISE-2000 have significant errors. Dynamic calibration of the atmosphere (DCA) has provided measurable improvements to the empirical density models and accelerometer derived densities of extremely high precision are available for a few satellites. However, DCA generally relies on observations of limited accuracy and accelerometer derived densities are extremely limited in terms of measurement coverage at any given time. The goal of this research is to provide an additional data source using satellites that have precision orbits available using Global Positioning System measurements and/or satellite laser ranging. These measurements strike a balance between the global coverage provided by DCA and the precise measurements of accelerometers. The temporal resolution of the POE derived density estimates is around 20-30 minutes, which is significantly worse than that of accelerometer derived density estimates. However, major variations in density are observed in the POE derived densities. These POE derived densities in combination with other data sources can be assimilated into physics based general circulation models of the thermosphere and ionosphere with the possibility of providing improved density forecasts for satellite drag analysis. POE derived density estimates were initially developed using CHAMP and GRACE data so comparisons could be made with accelerometer derived density estimates. This paper presents the results of the most extensive calibration of POE derived densities compared to accelerometer derived densities and provides the reasoning for selecting certain parameters in the estimation process. The factors taken into account for these selections are the cross correlation and RMS performance compared to the accelerometer derived densities and the output of the ballistic coefficient estimation that occurs simultaneously with the density estimation. This paper also presents the complete data set of CHAMP and GRACE results and shows that the POE derived densities match the accelerometer densities better than empirical models or DCA. This paves the way to expand the POE derived densities to include other satellites with quality GPS and/or satellite laser ranging observations.

Project CHAMP, 1986-1987. OEA Evaluation Report.

ERIC Educational Resources Information Center

Cabrera, Eulalia; And Others

In its fourth year, Project CHAMP (Chinese Achievement and Mastery Program) provided instruction in English as a second language (ESL), native language arts, mathematics, science, and social studies to 728 limited-English-speaking Chinese immigrant students in grades nine through twelve at three schools. Content-area classes were taught in English…

Project CHAMP, 1985-1986. OEA Evaluation Report.

ERIC Educational Resources Information Center

New York City Board of Education, Brooklyn. Office of Educational Assessment.

The Chinese Achievement and Mastery program, Project CHAMP, was a bilingual (Chinese/English) project offered at three high schools in Manhattan. The major goals were to enable Chinese students of limited English proficiency (LEP) to learn English and to master content in mathematics, science, global history, computer mathematics, and native…

A MULTIDISCIPLINARY APPROACH TO THE REHABILITATION OF A COLLEGIATE FOOTBALL PLAYER FOLLOWING ANKLE FRACTURE: A CASE REPORT

PubMed Central

Kaplan, Lee D.; Musto, Tony; Gaunaurd, Ignacio A.; Gailey, Robert S.; Kelley, William P.; Alemi, Timothy J.; Espinosa, Braulio; Mandler, Eli; Scavo, Vincent A.; West, Dustin C.

2016-01-01

ABSTRACT Background and Purpose Multiple rehabilitation factors including overall wellness need to be considered when an athlete returns to sport after an injury. The purpose of this case report is to describe a multidisciplinary approach for return to sport of a Division I collegiate football player following a traumatic ankle fracture requiring surgical repair. The assessment and treatment approach included the use of a performance-based physical therapy outcome measure, self-reported functional abilities, body composition assessments, and nutritional counseling. Case Description A 21 year-old running back fractured his lateral malleolus due to a mechanism of injury of excessive eversion with external rotation of the ankle. Surgical intervention included an open reduction internal fixation (ORIF) of the fibula and syndesmosis. In addition to six months of rehabilitation, the patient received consultations from the team sports nutritionist specialist to provide dietary counseling and body composition testing. The Comprehensive High-level Activity Mobility Predictor-Sport (CHAMP-S), a performance-based outcome measure, self-report on the Foot and Ankle Disability Index (FADI-ADL, FADI-S), and body composition testing using whole body densitometry (BOD POD®), were administered throughout rehabilitation. Outcomes The subject was successfully rehabilitated, returned to his starting role, and subsequently was drafted by a National Football League (NFL) franchise. High-level mobility returned to above pre-injury values, achieving 105% of his preseason CHAMP-S score at discharge. Self-reported function on the FADI-ADL and FADI-Sport improved to 100% at discharge. Body fat percentages decreased (13.3% to 11.9%) and fat mass decreased (12.0 kg to 11.0kg). Lean body mass (78.1 kg to 81.5 kg) and lbm/in increased (1.14 kg/in to 1.19 kg/in). His BMI changed from 29.8 kg/m2 to 30.6 kg/m2. Discussion This case report illustrates the positive effects of a multidisciplinary approach where combining physical therapy and nutritional counseling demonstrated value with return to sport preparation and success following ankle fracture. A targeted physical therapy program combined with a personalized nutrition intervention based on body composition assessment assisted this athlete in avoiding deconditioning (atrophy, decreased aerobic capacities, and increases in body fat) often observed during postoperative care. Level of Evidence 5 PMID:27274429

A MULTIDISCIPLINARY APPROACH TO THE REHABILITATION OF A COLLEGIATE FOOTBALL PLAYER FOLLOWING ANKLE FRACTURE: A CASE REPORT.

PubMed

Feigenbaum, Luis A; Kaplan, Lee D; Musto, Tony; Gaunaurd, Ignacio A; Gailey, Robert S; Kelley, William P; Alemi, Timothy J; Espinosa, Braulio; Mandler, Eli; Scavo, Vincent A; West, Dustin C

2016-06-01

Multiple rehabilitation factors including overall wellness need to be considered when an athlete returns to sport after an injury. The purpose of this case report is to describe a multidisciplinary approach for return to sport of a Division I collegiate football player following a traumatic ankle fracture requiring surgical repair. The assessment and treatment approach included the use of a performance-based physical therapy outcome measure, self-reported functional abilities, body composition assessments, and nutritional counseling. A 21 year-old running back fractured his lateral malleolus due to a mechanism of injury of excessive eversion with external rotation of the ankle. Surgical intervention included an open reduction internal fixation (ORIF) of the fibula and syndesmosis. In addition to six months of rehabilitation, the patient received consultations from the team sports nutritionist specialist to provide dietary counseling and body composition testing. The Comprehensive High-level Activity Mobility Predictor-Sport (CHAMP-S), a performance-based outcome measure, self-report on the Foot and Ankle Disability Index (FADI-ADL, FADI-S), and body composition testing using whole body densitometry (BOD POD®), were administered throughout rehabilitation. The subject was successfully rehabilitated, returned to his starting role, and subsequently was drafted by a National Football League (NFL) franchise. High-level mobility returned to above pre-injury values, achieving 105% of his preseason CHAMP-S score at discharge. Self-reported function on the FADI-ADL and FADI-Sport improved to 100% at discharge. Body fat percentages decreased (13.3% to 11.9%) and fat mass decreased (12.0 kg to 11.0kg). Lean body mass (78.1 kg to 81.5 kg) and lbm/in increased (1.14 kg/in to 1.19 kg/in). His BMI changed from 29.8 kg/m(2) to 30.6 kg/m(2). This case report illustrates the positive effects of a multidisciplinary approach where combining physical therapy and nutritional counseling demonstrated value with return to sport preparation and success following ankle fracture. A targeted physical therapy program combined with a personalized nutrition intervention based on body composition assessment assisted this athlete in avoiding deconditioning (atrophy, decreased aerobic capacities, and increases in body fat) often observed during postoperative care. 5.

Creating Healthy Active Minds for Personal Success (CHAMPS) in Middle School

ERIC Educational Resources Information Center

Shawley, Jessica

2016-01-01

The purpose of this article is to provide support for middle school physical education programs that meet the developmental needs of students while providing for student choice. With its health and physical education program called Creating Healthy Active Minds for Personal Success (CHAMPS), Moscow Middle School is striving to cultivate student…

Project CHAMP, 1983-1984: OEA Evaluation Report.

ERIC Educational Resources Information Center

New York City Board of Education, Brooklyn. Office of Educational Assessment.

Project CHAMP provides instruction in English as a second language (ESL), native language arts, and content-area instruction in mathematics, science, and social studies to Chinese students of limited English proficiency (LEP) in three New York City high schools: Seward Park, Washington Irving, and Martin Luther King, Jr. In 1983-84, the first year…

Evaluation of Refractivity Profiles from CHAMP and SAC-C GPS Radio Occultation

NASA Technical Reports Server (NTRS)

Poli, Paul; Ao, Chi On; Joiner, Joanna; delaTorreJuarez, Manuel; Hoff, Raymond

2002-01-01

The GeoForschungsZentrum's Challenging Minisatellite Payload for Geophysical Research and Application (CHAMP, Germany-US) and the Comision Nacional de Actividades Especiales' Satelite de Aplicaciones Cientificas-C (SAC-C, Argentina-US) missions are the first missions to carry a second-generation Blackjack Global Positioning System (GPS) receiver. One of the new features of this receiver is its ability to sense the lower troposphere closer to the surface than the proof-of-concept GPS Meteorology experiment (GPS/MET). Since their launch, CHAMP and SAC-C have collected thousands of GPS radio occultations, representing a wealth of measurements available for data assimilation and Numerical Weather Prediction (NWP). In order to evaluate the refractivity data derived by the Jet Propulsion Laboratory (JPL) from raw radio occultation measurements, we use Data Assimilation Office (DAO) 6-hour forecasts as an independent state of the atmosphere. We compare CHAMP and SAC-C refractivity (processed by JPL) with refractivity calculated from the DAO global fields of temperature, water vapor content and humidity. We show statistics of the differences as well as histograms of the differences.

Motivators and Barriers to Participation of Ethnic Minority Families in a Family-Based HIV Prevention Program

PubMed Central

Pinto, Rogério M.; McKay, Mary M.; Baptiste, Donna; Bell, Carl C.; Madison-Boyd, Sybil; Paikoff, Roberta; Wilson, Marla; Phillips, Daisy

2010-01-01

SUMMARY Involving low-income, ethnic minority families in lengthy HIV prevention programs can be challenging. Understanding the motivators and barriers to involvement may help researchers and practitioners design programs that can be used by populations most at risk for HIV exposure. The present study discusses motivators and barriers to involvement in the Collaborative HIV Prevention and Adolescent Mental Health Project (CHAMP), using data from a sample of 118 families that participated at varying levels in the twelve sessions of the program. Most participants chose motivators that reflect their perceptions of individual and/or family needs (“CHAMP might help me, mine, and other families”), and of characteristics of the program, such as CHAMP staff were friendly, CHAMP was fun. Among barriers to involvement, respondents expressed concerns about confidentiality, and about being judged by program staff. Respondents also reported experiencing many stressful events in their families (e.g., death and violence in the family) that may have been barriers to their involvement. Knowing these motivators and barriers, researchers and practitioners can enhance involvement in HIV prevention programs. PMID:20686648

Motivators and Barriers to Participation of Ethnic Minority Families in a Family-Based HIV Prevention Program.

PubMed

Pinto, Rogério M; McKay, Mary M; Baptiste, Donna; Bell, Carl C; Madison-Boyd, Sybil; Paikoff, Roberta; Wilson, Marla; Phillips, Daisy

2007-05-01

Involving low-income, ethnic minority families in lengthy HIV prevention programs can be challenging. Understanding the motivators and barriers to involvement may help researchers and practitioners design programs that can be used by populations most at risk for HIV exposure. The present study discusses motivators and barriers to involvement in the Collaborative HIV Prevention and Adolescent Mental Health Project (CHAMP), using data from a sample of 118 families that participated at varying levels in the twelve sessions of the program. Most participants chose motivators that reflect their perceptions of individual and/or family needs ("CHAMP might help me, mine, and other families"), and of characteristics of the program, such as CHAMP staff were friendly, CHAMP was fun. Among barriers to involvement, respondents expressed concerns about confidentiality, and about being judged by program staff. Respondents also reported experiencing many stressful events in their families (e.g., death and violence in the family) that may have been barriers to their involvement. Knowing these motivators and barriers, researchers and practitioners can enhance involvement in HIV prevention programs.

Using the Multiplicative Schwarz Alternating Algorithm (MSAA) for Solving the Large Linear System of Equations Related to Global Gravity Field Recovery up to Degree and Order 120

NASA Astrophysics Data System (ADS)

Safari, A.; Sharifi, M. A.; Amjadiparvar, B.

2010-05-01

The GRACE mission has substantiated the low-low satellite-to-satellite tracking (LL-SST) concept. The LL-SST configuration can be combined with the previously realized high-low SST concept in the CHAMP mission to provide a much higher accuracy. The line of sight (LOS) acceleration difference between the GRACE satellite pair is the mostly used observable for mapping the global gravity field of the Earth in terms of spherical harmonic coefficients. In this paper, mathematical formulae for LOS acceleration difference observations have been derived and the corresponding linear system of equations has been set up for spherical harmonic up to degree and order 120. The total number of unknowns is 14641. Such a linear equation system can be solved with iterative solvers or direct solvers. However, the runtime of direct methods or that of iterative solvers without a suitable preconditioner increases tremendously. This is the reason why we need a more sophisticated method to solve the linear system of problems with a large number of unknowns. Multiplicative variant of the Schwarz alternating algorithm is a domain decomposition method, which allows it to split the normal matrix of the system into several smaller overlaped submatrices. In each iteration step the multiplicative variant of the Schwarz alternating algorithm solves linear systems with the matrices obtained from the splitting successively. It reduces both runtime and memory requirements drastically. In this paper we propose the Multiplicative Schwarz Alternating Algorithm (MSAA) for solving the large linear system of gravity field recovery. The proposed algorithm has been tested on the International Association of Geodesy (IAG)-simulated data of the GRACE mission. The achieved results indicate the validity and efficiency of the proposed algorithm in solving the linear system of equations from accuracy and runtime points of view. Keywords: Gravity field recovery, Multiplicative Schwarz Alternating Algorithm, Low-Low Satellite-to-Satellite Tracking

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

Meng, F.; Banks, J. W.; Henshaw, W. D.

We describe a new partitioned approach for solving conjugate heat transfer (CHT) problems where the governing temperature equations in different material domains are time-stepped in a implicit manner, but where the interface coupling is explicit. The new approach, called the CHAMP scheme (Conjugate Heat transfer Advanced Multi-domain Partitioned), is based on a discretization of the interface coupling conditions using a generalized Robin (mixed) condition. The weights in the Robin condition are determined from the optimization of a condition derived from a local stability analysis of the coupling scheme. The interface treatment combines ideas from optimized-Schwarz methods for domain-decomposition problems togethermore » with the interface jump conditions and additional compatibility jump conditions derived from the governing equations. For many problems (i.e. for a wide range of material properties, grid-spacings and time-steps) the CHAMP algorithm is stable and second-order accurate using no sub-time-step iterations (i.e. a single implicit solve of the temperature equation in each domain). In extreme cases (e.g. very fine grids with very large time-steps) it may be necessary to perform one or more sub-iterations. Each sub-iteration generally increases the range of stability substantially and thus one sub-iteration is likely sufficient for the vast majority of practical problems. The CHAMP algorithm is developed first for a model problem and analyzed using normal-mode the- ory. The theory provides a mechanism for choosing optimal parameters in the mixed interface condition. A comparison is made to the classical Dirichlet-Neumann (DN) method and, where applicable, to the optimized- Schwarz (OS) domain-decomposition method. For problems with different thermal conductivities and dif- fusivities, the CHAMP algorithm outperforms the DN scheme. For domain-decomposition problems with uniform conductivities and diffusivities, the CHAMP algorithm performs better than the typical OS scheme with one grid-cell overlap. Lastly, the CHAMP scheme is also developed for general curvilinear grids and CHT ex- amples are presented using composite overset grids that confirm the theory and demonstrate the effectiveness of the approach.« less

The CHAOS-4 geomagnetic field model

NASA Astrophysics Data System (ADS)

Olsen, Nils; Lühr, Hermann; Finlay, Christopher C.; Sabaka, Terence J.; Michaelis, Ingo; Rauberg, Jan; Tøffner-Clausen, Lars

2014-05-01

We present CHAOS-4, a new version in the CHAOS model series, which aims to describe the Earth's magnetic field with high spatial and temporal resolution. Terms up to spherical degree of at least n = 85 for the lithospheric field, and up to n = 16 for the time-varying core field are robustly determined. More than 14 yr of data from the satellites Ørsted, CHAMP and SAC-C, augmented with magnetic observatory monthly mean values have been used for this model. Maximum spherical harmonic degree of the static (lithospheric) field is n = 100. The core field is expressed by spherical harmonic expansion coefficients up to n = 20; its time-evolution is described by order six splines, with 6-month knot spacing, spanning the time interval 1997.0-2013.5. The third time derivative of the squared radial magnetic field component is regularized at the core-mantle boundary. No spatial regularization is applied to the core field, but the high-degree lithospheric field is regularized for n > 85. CHAOS-4 model is derived by merging two submodels: its low-degree part has been derived using similar model parametrization and data sets as used for previous CHAOS models (but of course including more recent data), while its high-degree lithospheric field part is solely determined from low-altitude CHAMP satellite observations taken during the last 2 yr (2008 September-2010 September) of the mission. We obtain a good agreement with other recent lithospheric field models like MF7 for degrees up to n = 85, confirming that lithospheric field structures down to a horizontal wavelength of 500 km are currently robustly determined.

Southern Argentina Agile Meteor Radar: Initial assessment of gravity wave momentum fluxes

NASA Astrophysics Data System (ADS)

Fritts, D. C.; Janches, D.; Hocking, W. K.

2010-10-01

The Southern Argentina Agile Meteor Radar (SAAMER) was installed on Tierra del Fuego (53.8°S) in May 2008 and has been operational since that time. This paper describes tests of the SAAMER ability to measure gravity wave momentum fluxes and applications of this capability during different seasons. Test results for specified mean, tidal, and gravity wavefields, including tidal amplitudes and gravity wave momentum fluxes varying strongly with altitude and/or time, suggest that the distribution of meteors throughout the diurnal cycle and averaged over a month allows characterization of both monthly mean profiles and diurnal variations of the gravity wave momentum fluxes. Applications of the same methods for real data suggest confidence in the monthly mean profiles and the composite day diurnal variations of gravity wave momentum fluxes at altitudes where meteor counts are sufficient to yield good statistical fits to the data. Monthly mean zonal winds and gravity wave momentum fluxes exhibit anticorrelations consistent with those seen at other midlatitude and high-latitude radars during austral spring and summer, when no strong local gravity wave sources are apparent. When stratospheric variances are significantly enhanced over the Drake Passage “hot spot” during austral winter, however, MLT winds and momentum fluxes over SAAMER exhibit very different correlations that suggest that MLT dynamics are strongly influenced by strong local gravity wave sources within this “hot spot.” SAAMER measurements of mean zonal and meridional winds at these times and their differences from measurements at a conjugate site provide further support for the unusual momentum flux measurements.

Modern Data Analysis techniques in Noise and Vibration Problems

DTIC Science & Technology

1981-11-01

Hilbert l’une de l’autre. Cette propriete se retrouve dans l’etude de la causalite : ce qui de- finit un critere pratique caracterisant un signal donc, par...entre Ie champ direct et Ie champ reflechi se caracterisent loca- lement par l’existence de frequences pour lesquelles l’interference est totale

Factors associated with colostral specific gravity in dairy cows.

PubMed

Morin, D E; Constable, P D; Maunsell, F P; McCoy, G C

2001-04-01

The objectives of this study were to identify factors associated with colostral specific gravity in dairy cows, as measured by a commercially available hydrometer (Colostrometer). Colostral specific gravity was measured in 1085 first-milking colostrum samples from 608 dairy cows of four breeds on a single farm during a 5-yr period. Effects of breed, lactation number, and month and year of calving on colostral specific gravity were determined, as were correlations between colostral specific gravity, nonlactating period length, and 305-d yields of milk, protein, and fat. For 75 multiparous Holstein cows, relationships between colostral specific gravity, colostral IgG1, protein, and fat concentrations, and season of calving were determined. Colostral specific gravity values were lower for Brown Swiss and Ayrshire cows than for Jersey and Holstein cows, and lower for cows entering first or second lactation than third or later lactations. Month of calving markedly affected colostral specific gravity values, with highest values occurring in autumn and lowest values in summer. In multiparous Holstein cows, colostral specific gravity was more strongly correlated with colostral protein concentration (r = 0.76) than IgG1 concentration (r = 0.53), and colostral protein concentration varied seasonally (higher in autumn than summer). Our results demonstrate that colostral specific gravity more closely reflects colostral protein concentration than IgG1 concentration and is markedly influenced by month of calving. These results highlight potential limitations of using colostral specific gravity as an indicator of IgG1 concentration.

Indicators to assess the environmental performances of an innovative subway station : example of Noisy-Champs

NASA Astrophysics Data System (ADS)

Schertzer, D. J. M.; Charbonnier, L.; Versini, P. A.; Tchiguirinskaia, I.

2017-12-01

Noisy-Champs is a train station located in Noisy-le-Grand and Champs-sur-Marne, in the Paris urban area (France). Integrated into the Grand Paris Express project (huge development project to modernise the transport network around Paris), this station is going to be radically transformed and become a major hub. Designed by the architectural office Duthilleul, the new Noisy-Champs station aspires to be an example of an innovative and sustainable infrastructure. Its architectural precepts are indeed meant to improve its environmental performances, especially those related to storm water management, water consumption and users' thermal and hygrometric comfort. In order to assess and monitor these performances, objectives and associated indicators have been developed. They aim to be adapted for a specific infrastructure such as a public transport station. Analyses of pre-existing comfort simulations, blueprints and regulatory documents have led to identify the main issues for the Noisy-Champs station, focusing on its resilience to extreme events like droughts, heatwaves and heaxvy rainfalls. Both objectives and indicators have been proposed by studying the space-time variabilities of physical fluxes (heat, pollutants, radiation, wind and water) and passenger flows, and their interactions. Each indicator is linked to an environmental performance and has been determined after consultation of the different stakeholders involved in the rebuilding of the station. It results a monitoring program to assess the environmental performances of the station composed by both the indicators grid and their related objectives, and a measurement program detailing the nature and location of sensors, and the frequency of measurements.

A Transportable Gravity Gradiometer Based on Atom Interferometry

NASA Technical Reports Server (NTRS)

Yu, Nan; Thompson, Robert J.; Kellogg, James R.; Aveline, David C.; Maleki, Lute; Kohel, James M.

2010-01-01

A transportable atom interferometer-based gravity gradiometer has been developed at JPL to carry out measurements of Earth's gravity field at ever finer spatial resolutions, and to facilitate high-resolution monitoring of temporal variations in the gravity field from ground- and flight-based platforms. Existing satellite-based gravity missions such as CHAMP and GRACE measure the gravity field via precise monitoring of the motion of the satellites; i.e. the satellites themselves function as test masses. JPL's quantum gravity gradiometer employs a quantum phase measurement technique, similar to that employed in atomic clocks, made possible by recent advances in laser cooling and manipulation of atoms. This measurement technique is based on atomwave interferometry, and individual laser-cooled atoms are used as drag-free test masses. The quantum gravity gradiometer employs two identical atom interferometers as precision accelerometers to measure the difference in gravitational acceleration between two points (Figure 1). By using the same lasers for the manipulation of atoms in both interferometers, the accelerometers have a common reference frame and non-inertial accelerations are effectively rejected as common mode noise in the differential measurement of the gravity gradient. As a result, the dual atom interferometer-based gravity gradiometer allows gravity measurements on a moving platform, while achieving the same long-term stability of the best atomic clocks. In the laboratory-based prototype (Figure 2), the cesium atoms used in each atom interferometer are initially collected and cooled in two separate magneto-optic traps (MOTs). Each MOT, consisting of three orthogonal pairs of counter-propagating laser beams centered on a quadrupole magnetic field, collects up to 10(exp 9) atoms. These atoms are then launched vertically as in an atom fountain by switching off the magnetic field and introducing a slight frequency shift between pairs of lasers to create a moving rest frame for the trapped atoms. While still in this moving-frame molasses, the laser frequencies are further detuned from the atomic resonance (while maintaining this relative frequency shift) to cool the atom cloud's temperature to 2 K or below, corresponding to an rms velocity of less than 2 cm/s. After launch, the cold atoms undergo further state and velocity selection to prepare for atom interferometry. The atom interferometers are then realized using laser-induced stimulated Raman transitions to perform the necessary manipulations of each atom, and the resulting interferometer phase is measured using laser-induced fluorescence for state-normalized detection. More than 20 laser beams with independent controls of frequency, phase, and intensity are required for this measurement sequence. This instrument can facilitate the study of Earth's gravitational field from surface and air vehicles, as well as from space by allowing gravity mapping from a low-cost, single spacecraft mission. In addition, the operation of atom interferometer-based instruments in space offers greater sensitivity than is possible in terrestrial instruments due to the much longer interrogation times available in the microgravity environment. A space-based quantum gravity gradiometer has the potential to achieve sensitivities similar to the GRACE mission at long spatial wavelengths, and will also have resolution similar to GOCE for measurement at shorter length scales.

Taking Their Show on the Road: Becky Hebert & Siobhan Champ-Blackwell--National Network of Libraries of Medicine

ERIC Educational Resources Information Center

Library Journal, 2005

2005-01-01

They're two very different women with the same mission: outreach to medically underserved populations. Both work for the National Network of Libraries of Medicine. Becky Hebert (left) covers the Southeast/Atlantic region, and Siobhan Champ-Blackwell, the mid-continental region. They spend much of their lives on the road, exhibiting at minority…

Mediterranean studies of cardiovascular disease and hyperglycemia: analytical modeling of population socio-economic transitions (MedCHAMPS)--rationale and methods.

PubMed

Maziak, Wasim; Critchley, Julia; Zaman, Shahaduz; Unwin, Nigel; Capewell, Simon; Bennett, Kathleen; Unal, Belgin; Husseini, Abdullatif; Romdhane, Habiba Ben; Phillimore, Peter

2013-08-01

In response to the escalating epidemic of cardiovascular disease (CVD) in the Mediterranean Region (MR), an international collaboration aiming at understanding the burden of CVD and evaluating cost-effective strategies to combat it was recently established. This paper describes the rationale and methods of the project MedCHAMPS to disseminate this successful experience. The framework of MedCHAMPS is exceptional in combining multiple disciplines (e.g. epidemiology, anthropology, economics), countries [Turkey, Syria, occupied Palestinian territory (oPt), Tunisia, UK, Ireland], research methods (situational and policy analysis, quantitative and qualitative studies, statistical modeling), and involving local stakeholders at all levels to assess trends of CVD/diabetes in the society and attributes of the local health care systems to provide optimal policy recommendations to reduce the burden of CVD/diabetes. MedCHAMPS provides policy makers in the MR and beyond needed guidance about the burden of CVD, and best cost-effective ways to combat it. Our approach of building developed-developing countries collaboration also provides a roadmap for other researchers seeking to build research base into CVD epidemiology and prevention in developing countries.

CHAMP/GPS water vapor compared with a NWP model and with AMSU/B data

NASA Astrophysics Data System (ADS)

Johnsen, K.-P.; Miao, J.

2003-04-01

The atmospheric water vapor plays a dominant role in the hydrological cycle and in the radiative balance. It is very important for the greenhouse effect in climate modelling as well as for short term numerical weather prediction. Specific humidities derived from CHAMP/GPS are compared with the High resolution Regional weather forecast Model HRM of the Deutscher Wetterdienst over Europe during the BALTEX/Bridge baseline period (October 1999 to February 2002): The model shows slightly larger specific humidities than the radio occultation data obtained from CHAMP (decreasing with increasing height) up to about 1.5~g/kg. Vertically integrated water vapor (IWV) data derived from the CHAMP/GPS profiles are also compared with IWV data derived from AMSU/B data over Antarctica. The AMSU/B IWV data were calculated using an algorithm of Miao (1999). The mean difference between both datasets is with -0.08 kg/m2 quite low and the standard deviation is about 0.79 kg/m2.[0.3cm] Miao, J: Retrieval of Atmospheric Water Vapor Content in Polar Regions Using Spaceborne Microwave Radiometry, Ph.D. thesis, Reports on Polar Research 289, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany, 1998

Investigation of Electrostatic Accelerometer in HUST for Space Science Missions

NASA Astrophysics Data System (ADS)

Bai, Yanzheng; Hu, Ming; Li, Gui; Liu, Li; Qu, Shaobo; Wu, Shuchao; Zhou, Zebing

2014-05-01

High-precision electrostatic accelerometers are significant payload in CHAMP, GRACE and GOCE gravity missions to measure the non-gravitational forces. In our group, space electrostatic accelerometer and inertial sensor based on the capacitive sensors and electrostatic control technique has been investigated for space science research in China such as testing of equivalence principle (TEPO), searching non-Newtonian force in micrometer range, satellite Earth's field recovery and so on. In our group, a capacitive position sensor with a resolution of 10-7pF/Hz1/2 and the μV/Hz1/2 level electrostatic actuator are developed. The fiber torsion pendulum facility is adopt to measure the parameters of the electrostatic controlled inertial sensor such as the resolution, and the electrostatic stiffness, the cross couple between different DOFs. Meanwhile, high voltage suspension and free fall methods are applied to verify the function of electrostatic accelerometer. Last, the engineering model of electrostatic accelerometer has been developed and tested successfully in space and preliminary results are present.

Using the RE-AIM framework to evaluate a community-based summer camp for children with obesity: a prospective feasibility study.

PubMed

Burke, Shauna M; Shapiro, Sheree; Petrella, Robert J; Irwin, Jennifer D; Jackman, Michelle; Pearson, Erin S; Prapavessis, Harry; Shoemaker, Joel Kevin

2015-01-01

Increasing rates of childhood overweight and obesity highlight a need for the evaluation of lifestyle interventions. The purpose of the study was to determine the Reach, Effectiveness, Adoption, Implementation and Maintenance of a novel family-focused program targeting children with obesity (i.e., the Children's Health and Activity Modification Program [C.H.A.M.P.]) using the RE-AIM framework, an evaluation tool for community-based health interventions. A single-centre, single cohort interventional feasibility study was conducted over the course of two years. Children with obesity and their families completed a 4-week group-based lifestyle intervention in Year 1 (n = 15; M age = 10.6; 53% female) and/or Year 2 (n = 25; M age = 10.6; 56% female). Outcome variables were measured pre- and post-intervention, as well as 6- and 12-months following completion of the formal program. Overall, C.H.A.M.P. had high reach in terms of participant representativeness. In addition, participation in the program was associated with significantly improved standardized body mass index (BMI-z), body fat percentage, lean mass percentage, and child- and parent-proxy reported quality of life (QOL; effectiveness/individual maintenance). Furthermore, a number of community partnerships were built, strengthened, and maintained prior to, during, and following implementation of the two-year program (adoption/setting maintenance, respectively). Finally, the intervention was delivered as intended as evidenced by high adherence to the schedule, attendance rates, and cost effectiveness (implementation). Based on RE-AIM metrics, C.H.A.M.P. appears to be a promising childhood obesity program. The findings reported will inform researchers and practitioners on how to design and implement future community-based programs addressing pediatric obesity. ISRCTN Registry, Study ID ISRCTN13143236. Registered 27 March 2015.

ChAMP: updated methylation analysis pipeline for Illumina BeadChips.

PubMed

Tian, Yuan; Morris, Tiffany J; Webster, Amy P; Yang, Zhen; Beck, Stephan; Feber, Andrew; Teschendorff, Andrew E

2017-12-15

The Illumina Infinium HumanMethylationEPIC BeadChip is the new platform for high-throughput DNA methylation analysis, effectively doubling the coverage compared to the older 450 K array. Here we present a significantly updated and improved version of the Bioconductor package ChAMP, which can be used to analyze EPIC and 450k data. Many enhanced functionalities have been added, including correction for cell-type heterogeneity, network analysis and a series of interactive graphical user interfaces. ChAMP is a BioC package available from https://bioconductor.org/packages/release/bioc/html/ChAMP.html. a.teschendorff@ucl.ac.uk or s.beck@ucl.ac.uk or a.feber@ucl.ac.uk. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

Instruments for Imaging from Far to Near

NASA Technical Reports Server (NTRS)

Mungas, Greg; Boynton, John; Sepulveda, Cesar

2009-01-01

The acronym CHAMP (signifying camera, hand lens, and microscope ) denotes any of several proposed optoelectronic instruments that would be capable of color imaging at working distances that could be varied continuously through a range from infinity down to several millimeters. As in any optical instrument, the magnification, depth of field, and spatial resolution would vary with the working distance. For example, in one CHAMP version, at a working distance of 2.5 m, the instrument would function as an electronic camera with a magnification of 1/100, whereas at a working distance of 7 mm, the instrument would function as a microscope/electronic camera with a magnification of 4.4. Moreover, as described below, when operating at or near the shortest-working-distance/highest-magnification combination, a CHAMP could be made to perform one or more spectral imaging functions. CHAMPs were originally intended to be used in robotic geological exploration of the Moon and Mars. The CHAMP concept also has potential for diverse terrestrial applications that could include remotely controlled or robotic geological exploration, prospecting, field microbiology, environmental surveying, and assembly- line inspection. A CHAMP (see figure) would include two lens cells: (1) a distal cell corresponding to the objective lens assembly of a conventional telescope or microscope and (2) a proximal cell that would contain the focusing camera lens assembly and the camera electronic image-detector chip, which would be of the active-pixel-sensor (APS) type. The distal lens cell would face outward from a housing, while the proximal lens cell would lie in a clean environment inside the housing. The proximal lens cell would contain a beam splitter that would enable simultaneous use of the imaging optics (that is, proximal and distal lens assemblies) for imaging and illumination of the field of view. The APS chip would be mounted on a focal plane on a side face of the beam splitter, while light for illuminating the field of view would enter the imaging optics via the end face of the beam splitter. The proximal lens cell would be mounted on a sled that could be translated along the optical axis for focus adjustment. The position of the CHAMP would initially be chosen at the desired working distance of the distal lens from (corresponding to an approximate desired magnification of) an object to be examined. During subsequent operation, the working distance would ordinarily remain fixed at the chosen value and the position of the proximal lens cell within the instrument would be adjusted for focus as needed.

A stable and accurate partitioned algorithm for conjugate heat transfer

NASA Astrophysics Data System (ADS)

Meng, F.; Banks, J. W.; Henshaw, W. D.; Schwendeman, D. W.

2017-09-01

We describe a new partitioned approach for solving conjugate heat transfer (CHT) problems where the governing temperature equations in different material domains are time-stepped in an implicit manner, but where the interface coupling is explicit. The new approach, called the CHAMP scheme (Conjugate Heat transfer Advanced Multi-domain Partitioned), is based on a discretization of the interface coupling conditions using a generalized Robin (mixed) condition. The weights in the Robin condition are determined from the optimization of a condition derived from a local stability analysis of the coupling scheme. The interface treatment combines ideas from optimized-Schwarz methods for domain-decomposition problems together with the interface jump conditions and additional compatibility jump conditions derived from the governing equations. For many problems (i.e. for a wide range of material properties, grid-spacings and time-steps) the CHAMP algorithm is stable and second-order accurate using no sub-time-step iterations (i.e. a single implicit solve of the temperature equation in each domain). In extreme cases (e.g. very fine grids with very large time-steps) it may be necessary to perform one or more sub-iterations. Each sub-iteration generally increases the range of stability substantially and thus one sub-iteration is likely sufficient for the vast majority of practical problems. The CHAMP algorithm is developed first for a model problem and analyzed using normal-mode theory. The theory provides a mechanism for choosing optimal parameters in the mixed interface condition. A comparison is made to the classical Dirichlet-Neumann (DN) method and, where applicable, to the optimized-Schwarz (OS) domain-decomposition method. For problems with different thermal conductivities and diffusivities, the CHAMP algorithm outperforms the DN scheme. For domain-decomposition problems with uniform conductivities and diffusivities, the CHAMP algorithm performs better than the typical OS scheme with one grid-cell overlap. The CHAMP scheme is also developed for general curvilinear grids and CHT examples are presented using composite overset grids that confirm the theory and demonstrate the effectiveness of the approach.

The Chandra Multi-Wavelength Project (ChaMP): A Serendipitous X-Ray Survey Using Chandra Archival Data

NASA Technical Reports Server (NTRS)

Wilkes, Belinda; Lavoie, Anthony R. (Technical Monitor)

2000-01-01

The launch of the Chandra X-ray Observatory in July 2000 opened a new era in X-ray astronomy. Its unprecedented, < 1" spatial resolution and low background is providing views of the X-ray sky 10-100 times fainter than previously possible. We have begun to carry out a serendipitous survey of the X-ray sky using Chandra archival data to flux limits covering the range between those reached by current satellites and those of the small area Chandra deep surveys. We estimate the survey will cover about 8 sq.deg. per year to X-ray fluxes (2-10 keV) in the range 10(exp -13) - 6(exp -16) erg cm2/s and include about 3000 sources per year, roughly two thirds of which are expected to be active galactic nuclei (AGN). Optical imaging of the ChaMP fields is underway at NOAO and SAO telescopes using g',r',z' colors with which we will be able to classify the X-ray sources into object types and, in some cases, estimate their redshifts. We are also planning to obtain optical spectroscopy of a well-defined subset to allow confirmation of classification and redshift determination. All X-ray and optical results and supporting optical data will be place in the ChaMP archive within a year of the completion of our data analysis. Over the five years of Chandra operations, ChaMP will provide both a major resource for Chandra observers and a key research tool for the study of the cosmic X-ray background and the individual source populations which comprise it. ChaMP promises profoundly new science return on a number of key questions at the current frontier of many areas of astronomy including solving the spectral paradox by resolving the CXRB, locating and studying high redshift clusters and so constraining cosmological parameters, defining the true, possibly absorbed, population of quasars and studying coronal emission from late-type stars as their cores become fully convective. The current status and initial results from the ChaMP will be presented.

A stable and accurate partitioned algorithm for conjugate heat transfer

DOE PAGES

Meng, F.; Banks, J. W.; Henshaw, W. D.; ...

2017-04-25

We describe a new partitioned approach for solving conjugate heat transfer (CHT) problems where the governing temperature equations in different material domains are time-stepped in a implicit manner, but where the interface coupling is explicit. The new approach, called the CHAMP scheme (Conjugate Heat transfer Advanced Multi-domain Partitioned), is based on a discretization of the interface coupling conditions using a generalized Robin (mixed) condition. The weights in the Robin condition are determined from the optimization of a condition derived from a local stability analysis of the coupling scheme. The interface treatment combines ideas from optimized-Schwarz methods for domain-decomposition problems togethermore » with the interface jump conditions and additional compatibility jump conditions derived from the governing equations. For many problems (i.e. for a wide range of material properties, grid-spacings and time-steps) the CHAMP algorithm is stable and second-order accurate using no sub-time-step iterations (i.e. a single implicit solve of the temperature equation in each domain). In extreme cases (e.g. very fine grids with very large time-steps) it may be necessary to perform one or more sub-iterations. Each sub-iteration generally increases the range of stability substantially and thus one sub-iteration is likely sufficient for the vast majority of practical problems. The CHAMP algorithm is developed first for a model problem and analyzed using normal-mode the- ory. The theory provides a mechanism for choosing optimal parameters in the mixed interface condition. A comparison is made to the classical Dirichlet-Neumann (DN) method and, where applicable, to the optimized- Schwarz (OS) domain-decomposition method. For problems with different thermal conductivities and dif- fusivities, the CHAMP algorithm outperforms the DN scheme. For domain-decomposition problems with uniform conductivities and diffusivities, the CHAMP algorithm performs better than the typical OS scheme with one grid-cell overlap. Lastly, the CHAMP scheme is also developed for general curvilinear grids and CHT ex- amples are presented using composite overset grids that confirm the theory and demonstrate the effectiveness of the approach.« less

AIUB-RL02: an improved time-series of monthly gravity fields from GRACE data

NASA Astrophysics Data System (ADS)

Meyer, U.; Jäggi, A.; Jean, Y.; Beutler, G.

2016-05-01

The new release AIUB-RL02 of monthly gravity models from GRACE GPS and K-Band range-rate data is based on reprocessed satellite orbits referring to the reference frame IGb08. The release is consistent with the IERS2010 conventions. Improvements with respect to its predecessor AIUB-RL01 include the use of reprocessed (RL02) GRACE observations, new atmosphere and ocean dealiasing products (RL05), an upgraded ocean tide model (EOT11A), and the interpolation of shallow ocean tides (admittances). The stochastic parametrization of AIUB-RL02 was adapted to include daily accelerometer scale factors, which drastically reduces spurious signal at the 161 d period in C20 and at other low degree and order gravity field coefficients. Moreover, the correlation between the noise in the monthly gravity models and solar activity is considerably reduced in the new release. The signal and the noise content of the new AIUB-RL02 monthly gravity fields are studied and calibrated errors are derived from their non-secular and non-seasonal variability. The short-period time-variable signal over the oceans, mostly representing noise, is reduced by 50 per cent with respect to AIUB-RL01. Compared to the official GFZ-RL05a and CSR-RL05 monthly models, the AIUB-RL02 stands out by its low noise at high degrees, a fact emerging from the estimation of seasonal variations for selected river basins and of mass trends in polar regions. Two versions of the monthly AIUB-RL02 gravity models, with spherical harmonics resolution of degree and order 60 and 90, respectively, are available for the time period from March 2003 to March 2014 at the International Center for Global Earth Models or from ftp://ftp.unibe.ch/aiub/GRAVITY/GRACE (last accessed 22 March 2016).

Multi-instrumental Analysis of the Ionospheric Density Response to Geomagnetic Disturbances

NASA Astrophysics Data System (ADS)

Zakharenkova, I.; Astafyeva, E.

2014-12-01

Measurements provided by Low Earth Orbit (LEO) satellite missions have already proved to be very efficient in investigations of global redistribution of ionospheric plasma and thermosphere mass density during such phenomena as geomagnetic storms. LEO satellites have various instruments for research of the ionosphere response to the space weather events like GPS receiver for precise orbit determination (POD), total electron content estimation and radio occultation, altimeter, planar Langmuir probe, topside sounder, special detectors for particle fluxes, magnetometer etc. In this paper, we present results of joint analysis of LEO satellite data, in particular CHAMP, DMSP, JASON, as well as data provided by ground-based networks of GPS receivers and ionosonde stations for global ionospheric response to the geomagnetic disturbances. We use in-situ plasma density data from CHAMP and DMSP satellites, along with data of GPS receiver onboard CHAMP-satellite and ground-based GPS-receivers to study occurrence and global distribution of ionospheric irregularities during the main phase of the storm. Using CHAMP GPS measurements, we created maps of GPS phase fluctuation activity and found two specific zones of the most intense irregularities - first is the region of the auroral oval at high latitudes of both hemispheres, the second one is the low-latitudes/equatorial region between Africa and South America. The interhemispheric asymmetry of the ionospheric irregularities intensity and occurrence in polar region is discussed. Analysis of the topside TEC, derived from CHAMP onboard GPS POD antenna, indicate the significant redistribution of the topside ionospheric plasma density in the equatorial, middle and high-latitude ionosphere during main and recovery phases of geomagnetic storm. Multi-instrumental data allow to analyze in detail the complex modification and dynamics of the upper atmosphere in different altitudinal, spatial and temporal scales.

Estimation of the Earth's gravity field by combining normal equation matrices from GRACE and SLR

NASA Astrophysics Data System (ADS)

Haberkorn, Christoph; Bloßfeld, Mathis; Bouman, Johannes

2014-05-01

Since 2002, GRACE observes the Earth's gravity field with a spatial resolution up to 150 km. The main goal of this mission is the determination of temporal variations in the Earth's gravity field to detect mass displacements. The GRACE mission consists of two identical satellites, which observe the range along the line of sight of both satellites. GRACE observations can be linked with the Earth's gravitational potential, which is expressed in terms of spherical harmonics for global solutions. However, the estimation of low degree coefficients is difficult with GRACE. In contrast to gravity field missions, which observe the gravity field with high spectral resolution, SLR data allow to estimate the lower degree coefficients. Therefore, the coefficient C20 is often replaced by a value derived from Satellite Laser Ranging (SLR). Instead of replacing C20, it can be determined consistently by a combined estimation using GRACE and SLR data. We compute monthly normal equation (NEQ) matrices for GRACE and SLR. Coefficients from monthly GRACE gravity field models of different institutions (Center for Space Research (CSR), USA, Geoforschungszentrum Potsdam (GFZ), Germany and Jet Propulsion Laboratory (JPL), USA) and coefficients from monthly gravity field models of our SLR processing are then combined using the NEQ matrices from both techniques. We will evaluate several test scenarios with gravity field models from different institutions and with different set ups for the SLR NEQ matrices. The effect of the combination on the estimated gravity field will be analysed and presented.

[Antoine Béchamp and Victor Cornil Memento for Romanian pharmacy, chemistry and medicine].

PubMed

Buiuc, D; Pânzaru, Carmen

2008-01-01

Today we commemorate a century from the death of two Romanian loving scientists: Antoine Béchamp (1816- March 31 1908), pharmacist, chemist and physician, professor at the Universities of Strasbourg, Montpellier and Lille, and Victor Cornil (1837- April 14 1908), physician, histopathologist and bacteriologist, professor of the University of Medicine in Paris, co-author with Victor Babeş on the first ever Bacteriological Treaty.

Development and Optical Testing of the Camera, Hand Lens, and Microscope Probe with Scannable Laser Spectroscopy (CHAMP-SLS)

NASA Technical Reports Server (NTRS)

Mungas, Greg S.; Gursel, Yekta; Sepulveda, Cesar A.; Anderson, Mark; La Baw, Clayton; Johnson, Kenneth R.; Deans, Matthew; Beegle, Luther; Boynton, John

2008-01-01

Conducting high resolution field microscopy with coupled laser spectroscopy that can be used to selectively analyze the surface chemistry of individual pixels in a scene is an enabling capability for next generation robotic and manned spaceflight missions, civil, and military applications. In the laboratory, we use a range of imaging and surface preparation tools that provide us with in-focus images, context imaging for identifying features that we want to investigate at high magnification, and surface-optical coupling that allows us to apply optical spectroscopic analysis techniques for analyzing surface chemistry particularly at high magnifications. The camera, hand lens, and microscope probe with scannable laser spectroscopy (CHAMP-SLS) is an imaging/spectroscopy instrument capable of imaging continuously from infinity down to high resolution microscopy (resolution of approx. 1 micron/pixel in a final camera format), the closer CHAMP-SLS is placed to a feature, the higher the resultant magnification. At hand lens to microscopic magnifications, the imaged scene can be selectively interrogated with point spectroscopic techniques such as Raman spectroscopy, microscopic Laser Induced Breakdown Spectroscopy (micro-LIBS), laser ablation mass-spectrometry, Fluorescence spectroscopy, and/or Reflectance spectroscopy. This paper summarizes the optical design, development, and testing of the CHAMP-SLS optics.

Validation of a new plasmapause model derived from CHAMP field-aligned current signatures

NASA Astrophysics Data System (ADS)

Heilig, Balázs; Darrouzet, Fabien; Vellante, Massimo; Lichtenberger, János; Lühr, Hermann

2014-05-01

Recently a new model for the plasmapause location in the equatorial plane was introduced based on magnetic field observations made by the CHAMP satellite in the topside ionosphere (Heilig and Lühr, 2013). Related signals are medium-scale field-aligned currents (MSFAC) (some 10km scale size). An empirical model for the MSFAC boundary was developed as a function of Kp and MLT. The MSFAC model then was compared to in situ plasmapause observations of IMAGE RPI. By considering this systematic displacement resulting from this comparison and by taking into account the diurnal variation and Kp-dependence of the residuals an empirical model of the plasmapause location that is based on MSFAC measurements from CHAMP was constructed. As a first step toward validation of the new plasmapause model we used in-situ (Van Allen Probes/EMFISIS, Cluster/WHISPER) and ground based (EMMA) plasma density observations. Preliminary results show a good agreement in general between the model and observations. Some observed differences stem from the different definitions of the plasmapause. A more detailed validation of the method can take place as soon as SWARM and VAP data become available. Heilig, B., and H. Lühr (2013) New plasmapause model derived from CHAMP field-aligned current signatures, Ann. Geophys., 31, 529-539, doi:10.5194/angeo-31-529-2013

Influence de l'effet de peau sur la rotation d'un rotor fluide

NASA Astrophysics Data System (ADS)

Witkowski, L. Martin; Marty, Ph.

1998-01-01

A rotating magnetic field creates forces in a liquid metal column which therefore rotates. In the case of an infinitely long column, we solve the induction and Navier-Stokes equations. The results are described for the fully coupled case which arises when the Hartmann number Ha and the shield parameter R_{ω} are larger than unity. In this case, we distinguish between two velocity regimes upon the value of R_{ω} with respect to frac{Ha}{sqrt{2}}. Un champ magnétique tournant autour d'une colonne de métal liquide crée des forces qui la mettent en rotation. Dans le cas d'une colonne de hauteur infinie, il est proposé une méthode de résolution des équations couplées régissant la distribution du champ magnétique et du champ de vitesse. Les résultats sont détaillés quand le couplage est fort ce qui correspond à un nombre de Hartmann Ha et un paramètre d'écran R_{ω} grands devant l'unité. Dans ce cas, pour Ha donné, deux régimes apparaissent pour le champ de vitesse suivant que R_{ω} est supérieur ou inférieur à frac{Ha}{sqrt{2}}.

Monthly gravity field solutions based on GRACE observations generated with the Celestial Mechanics Approach

NASA Astrophysics Data System (ADS)

Meyer, Ulrich; Jäggi, Adrian; Beutler, Gerhard

2012-09-01

The main objective of the Gravity Recovery And Climate Experiment (GRACE) satellite mission consists of determining the temporal variations of the Earth's gravity field. These variations are captured by time series of gravity field models of limited resolution at, e.g., monthly intervals. We present a new time series of monthly models, which was computed with the so-called Celestial Mechanics Approach (CMA), developed at the Astronomical Institute of the University of Bern (AIUB). The secular and seasonal variations in the monthly models are tested for statistical significance. Calibrated errors are derived from inter-annual variations. The time-variable signal can be extracted at least up to degree 60, but the gravity field coefficients of orders above 45 are heavily contaminated by noise. This is why a series of monthly models is computed up to a maximum degree of 60, but only a maximum order of 45. Spectral analysis of the residual time-variable signal shows a distinctive peak at a period of 160 days, which shows up in particular in the C20 spherical harmonic coefficient. Basic filter- and scaling-techniques are introduced to evaluate the monthly models. For this purpose, the variability over the oceans is investigated, which serves as a measure for the noisiness of the models. The models in selected regions show the expected seasonal and secular variations, which are in good agreement with the monthly models of the Helmholtz Centre Potsdam, German Research Centre for Geosciences (GFZ). The results also reveal a few small outliers, illustrating the necessity for improved data screening. Our monthly models are available at the web page of the International Centre for Global Earth Models (ICGEM).

Changes in gravitational parameters inferred from time variable GRACE data-A case study for October 2005 Kashmir earthquake

NASA Astrophysics Data System (ADS)

Hussain, Matloob; Eshagh, Mehdi; Ahmad, Zulfiqar; Sadiq, M.; Fatolazadeh, Farzam

2016-09-01

The earth's gravity changes are attributed to the redistribution of masses within and/or on the surface of the earth, which are due to the frictional sliding, tensile cracking and/or cataclastic flow of rocks along the faults and detectable by earthquake events. Inversely, the gravity changes are useful to describe the earthquake seismicity over the active orogenic belts. The time variable gravimetric data are hardly available to the public domain. However, Gravity Recovery and Climatic Experiment (GRACE) is the only satellite mission dedicated to model the variation of the gravity field and an available source to the science community. Here, we have tried to envisage gravity changes in terms of gravity anomaly (Δg), geoid (N) and the gravity gradients over the Indo-Pak plate with emphasis upon Kashmir earthquake of October 2005. For this purpose, we engaged the spherical harmonic coefficients of monthly gravity solutions from the GRACE satellite mission, which have good coverage over the entire globe with unprecedented accuracy. We have analysed numerically the solutions after removing the hydrological signals, during August to November 2005, in terms of corresponding monthly differentials of gravity anomaly, geoid and the gradients. The regional structures like Main Mantle Thrust (MMT), Main Karakoram Thrust (MKT), Herat and Chaman faults are in closed association with topography and with gravity parameters from the GRACE gravimetry and EGM2008 model. The monthly differentials of these quantities indicate the stress accumulation in the northeast direction in the study area. Our numerical results show that the horizontal gravity gradients seem to be in good agreement with tectonic boundaries and differentials of the gravitational elements are subtle to the redistribution of rock masses and topography caused by 2005 Kashmir earthquake. Moreover, the gradients are rather more helpful for extracting the coseismic gravity signatures caused by seismicity over the area. Higher positive values of gravity components having higher terrain elevations are more vulnerable to the seismicity and lower risk of diastrophism otherwise.

Near real-time GRACE gravity field solutions for hydrological monitoring applications

NASA Astrophysics Data System (ADS)

Kvas, Andreas; Gouweleeuw, Ben; Mayer-Gürr, Torsten; Güntner, Andreas

2016-04-01

Within the EGSIEM (European Gravity Service for Improved Emergency Management) project, a demonstrator for a near real-time (NRT) gravity field service which provides daily GRACE gravity field solutions will be established. Compared to the official GRACE gravity products, these NRT solutions will increase the temporal resolution from one month to one day and reduce the latency from currently two months to five days. This fast availability allows the monitoring of total water storage variations and of hydrological extreme events as they occur, in contrast to a 'confirmation after occurrence' as is the situation today. The service will be jointly run by GFZ (German Research Centre for Geosciences) and Graz University of Technology, with each analysis center providing an independent solution. A Kalman filter framework, in which GRACE data is combined with prior information, serves as basis for the gravity field recovery in order to increase the redundancy of the gravity field estimates. The on-line nature of the NRT service necessitates a tailored smoothing algorithm as opposed to post-processing applications, where forward-backward smoothing can be applied. This contribution gives an overview on the near real-time processing chain and highlights differences between the computed NRT solutions and the standard GRACE products. We discuss the special characteristics of the Kalman filtered gravity field models as well as derived products and give an estimate of the expected error levels. Additionally, we show the added value of the NRT solutions through comparison of the first results of the pre-operational phase with in-situ data and monthly GRACE gravity field models.

The Impact of the Implementation of the Behavior Intervention Support CHAMPS on Reading Achievement, Discipline Referrals, and Number of Suspensions amongst Students Grades Third through Fifth within a Large Suburban Elementary School

ERIC Educational Resources Information Center

Smith, Jennifer L.

2017-01-01

The purpose of this study was to determine the impact of Randy Spricks (2009) behavior intervention support model, CHAMPS (Conversation, Help, Activity, Movement, Participation, Success), on elementary students in third through fifth grade in the areas of reading achievement, discipline referrals, and suspension numbers within a large culturally…

An Exospheric Temperature Model Based On CHAMP Observations and TIEGCM Simulations

NASA Astrophysics Data System (ADS)

Ruan, Haibing; Lei, Jiuhou; Dou, Xiankang; Liu, Siqing; Aa, Ercha

2018-02-01

In this work, thermospheric densities from the accelerometer measurement on board the CHAMP satellite during 2002-2009 and the simulations from the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM) are employed to develop an empirical exospheric temperature model (ETM). The two-dimensional basis functions of the ETM are first provided from the principal component analysis of the TIEGCM simulations. Based on the exospheric temperatures derived from CHAMP thermospheric densities, a global distribution of the exospheric temperatures is reconstructed. A parameterization is conducted for each basis function amplitude as a function of solar-geophysical and seasonal conditions. Thus, the ETM can be utilized to model the thermospheric temperature and mass density under a specified condition. Our results showed that the averaged standard deviation of the ETM is generally less than 10% than approximately 30% in the MSIS model. Besides, the ETM reproduces the global thermospheric evolutions including the equatorial thermosphere anomaly.

Temporal sea-surface gravity changes observed near the source area prior to the 2011 Tohoku earthquake

NASA Astrophysics Data System (ADS)

Nakamura, T.; Tsuboi, S.

2013-12-01

Recent seismological studies suggested subsurface activities preceding the 2011 Tohoku earthquake; the occurrence of migration of seismicity (Kato et al., 2012) and slow slip events (Ito et al., 2013) in and around the source area one month before the mainshock. In this study, we investigated sea-surface gravity changes observed by the shipboard gravimeter mounted on research vessels before the mainshock. The vessels incidentally passed through the source area along almost the same cruise track twice, four months before and one month before the mainshock. Comparing the sea surface gravity in the former track with that in the latter after Bouguer correction, we find the gravity changes of approximately 7 mGal in coseismic slip areas near the trench axis during the three months. We find these gravity changes even in the crossing areas of the cruise tracks where seafloor topographies have no differences between the tracks. We also find that the topographic differences show positive changes but the gravity changes negative ones in other areas, which is a negative correlation inconsistent with the theoretical relationship between the topographic difference and the gravity change. These mean that the differences of seafloor topographies due to differences between the two cruise tracks are not main causes of the observed gravity changes there. The changes cannot also be explained by drifts of the gravimeter and geostrophic currents. Although we have not had any clear evidences, we speculate that the possible cause may be density increases around the seismogenic zone or uplifts of seafloor in order to explain the changes of this size. We estimate the density increases of 1.0 g/cm**3 in a disk with a radius of 40 km and a width of 200 m or the uplifts of several tens of meters in seafloor areas for the observed gravity changes. Our results indicate that sea-surface gravity observations may be one of valid approaches to monitor the approximate location of a possible great earthquake in offshore areas.

Analyse de L'ancrage des Vortex Intergrains pour le Yttrium BARYUM(2) CUIVRE(3) OXYGENE(7) Polycristallin

NASA Astrophysics Data System (ADS)

Fournier, Patrick

Le Modele de l'Etat Critique Generalise (MECG) est utilise pour decrire les proprietes magnetiques et de transport du YBa_2Cu_3O _7 polycristallin. Ce modele empirique permet de relier la densite de courant critique a la densite de lignes de flux penetrant dans la region intergrain. Deux techniques de mesures sont utilisees pour caracteriser nos materiaux. La premiere consiste a mesurer le champ au centre d'un cylindre creux en fonction du champ magnetique applique pour des temperatures comprises entre 20 et 85K. En variant l'epaisseur de la paroi du cylindre creux, il est possible de suivre l'evolution des cycles d'hysteresis et de determiner des champs caracteristiques qui varient en fonction de cette dimension. En utilisant un lissage des resultats experimentaux, nous determinons J _{co}, H_ {o} et n, les parametres du MECG. La forme des cylindres, avec une longueur comparable au diametre externe, entrai ne la presence d'un champ demagnetisant qui peut etre inclus dans le modele theorique. Ceci nous permet d'evaluer la fraction du volume ecrante, f _{g}, ainsi que le facteur demagnetisant N. Nous trouvons que J_{ co}, H_{o} et f_{g} dependent de la temperature, tandis que n et N (pour une epaisseur de paroi fixe) n'en dependent pas. La deuxieme technique consiste a mesurer le courant critique de lames minces en fonction du champ applique pour differentes temperatures. Nous utilisons un montage que nous avons developpe permettant d'effectuer ces mesures en contact direct avec le liquide refrigerant, i.e. dans l'azote liquide. Nous varions la temperature du liquide en variant la pression du gaz au-dessus du bain d'azote. Cette methode nous permet de balayer des temperatures entre 65K et la temperature critique du materiau ({~ }92K). Nous effectuons le lissage des courbes de courant critique en fonction du champ applique encore a l'aide du MECG, pour a nouveau obtenir ses parametres. Pour trois echantillons avec des traitements thermiques differents, les parametres sont differents confirmant que la variation des proprietes macroscopiques de ces supraconducteurs est intimement reliee a la nature des jonctions entre les grains et de la surface des grains. L'oxygenation prolongee retablit les proprietes initiales des echantillons qui se sont degrades durant le recuit des contacts.

Electromagnetic properties of a modular MHD thruster

NASA Astrophysics Data System (ADS)

Kom, C. H.; Brunet, Y.

1999-04-01

The magnetic field of an annular MHD thruster made of independent superconducting modules has been studied with analytical and numerical methods. This configuration allows to obtain large magnetized volumes and high induction levels with rapidly decreasing stray fields. When some inductors are out of order, the thruster remains still operational, but the stray fields increase in the vicinity of the failure. For given structural materials and superconductors, it is possible to determine the size of the conductor in order to reduce the electromagnetic forces and the peak field supported by the conductors. For an active field of 10 T in a 6 m ray annular active channel of a thruster with 24 modules, the peak field is exactly 15.6 T in the Nb3Sn conductors and the structure has to sustain 10^8 N/m forces. The necessity to place some magnetic or superconducting shield is discussed, particularly when the thruster is in a degraded regime. Nous présentons une étude analytique et numérique du champ magnétique d'un propulseur MHD naval annulaire, constitué de secteurs inducteurs supraconducteurs. Cette configuration nécessite des champs magnétiques élevés dans des volumes importants, et permet une décroissance rapide des champs de fuite. Lorsque quelques inducteurs sont en panne, le propulseur reste toujours opérationnel, mais les champs de fuite sont importants aux environs des modules hors service. Étant donné un matériau supraconducteur, il est possible de déterminer la forme des inducteurs dans le but de réduire à la fois les forces électromagnétiques et le surchamp supporté par le bobinage. Pour un propulseur annulaire constitué de 24 modules inducteurs, et un champ actif de 10 T au centre de la partie active du canal (r = 6 m) on obtient avec du Nb3Sn un champ maximun sur le conducteur de 15,5 T et la structure supporte une force de 10^8 N/m. De plus, la nécessité de placer des écrans magnétique ou supraconducteur en régime dégradé (mise hors service d'un ou de plusieurs modules inducteurs) est discutée.

Methodology of Evaluating the Science Benefit of Various Satellite/Sensor Constellation Orbital Parameters to an Assimilative Data Forecast Model

DTIC Science & Technology

2015-03-02

and Aurora Spectrograph) inst1uments, and radio 129 occultation data from CHAMP (Challenging Minisatellite Payload), SAC-C (Satellite de 130...Aplicaciones Cientificas-C) [Hajj et al, 2004], IOX (Ionospheric Occultation Experiment) 131 [Straus et al, 2003], and the COSMIC (Constellation Observing...T. K. Meehan, L. 385 J. Romans, M. de la Torre Juarez. and T. P. Yunck (2004), CHAMP and SAC-C atmospheric 386 occultation results and

The Role of Neutral Atmospheric Dynamics in Cusp Density - 2nd Campaign

DTIC Science & Technology

2013-12-30

density enhancement at the CHAMP altitude of 400 km. Then Clemmons et al. (2008) presented observations from Distribution A: Approved for public release...250 km. This appeared to contradict the CHAMP observations, so Clemmons et al. proposed that heating occurred at an altitude above Streak, caused by...temperatures less than 1000 K. The ion temperatures can be related to the speed of the plasma as shown by St Maurice and Hanson (1982) using the assumption

Development and Reliability Testing of the Comprehensive High-Level Activity Mobility Predictor (CHAMP) in Male Servicemembers with Traumatic Lower-Limb Loss

DTIC Science & Technology

2013-01-01

Levin GT, Ben Abdelkrim N, Laurencelle L, Castagna C. Lower limb maxi- mal dynamic strength and agility determinants in elite basket - ball players . J...IRB = Institutional Review Board, LLL = lower-limb loss, MBP = Medicine Ball Put, MDC = minimal detectable change, NMCSD = Naval Medical Center...consid- ered for the CHAMP. Coordination, power, speed, and agility are important physical components necessary for successful perfor- mance in sports

Hydrologic Interpretations of Long-Term Gravity Records at Tucson, Arizona

NASA Astrophysics Data System (ADS)

Pool, D. R.; Kennedy, J.; MacQueen, P.; Niebauer, T. M.

2016-12-01

The USGS Arizona Water Science Center monitors groundwater storage using gravity methods at sites across the western United States. A site at the USGS office in Tucson serves as a test station that has been monitored since 1997 using several types of gravity meters. Prior to 2007, the site was observed twice each year by the National Geodetic Survey using an FG5 absolute gravity meter for the purpose of establishing control for local relative gravity surveys of aquifer storage change. Beginning in 2003 the site has also served as a reference to verify the accuracy of an A10 absolute gravity meter that is used for field surveys. The site is in an alluvial basin where gravity can vary with aquifer storage change caused by variable groundwater withdrawals, elevation change caused by aquifer compaction or expansion, and occasional recharge. In addition, continuous gravity records were collected for periods of several months using a super-conducting meter during 2010-2011 and using a spring-based gPhone meter during 2015-2016. The purpose of the continuous records was to provide more precise information about monthly and shorter period variations that could be related to variations in nearby groundwater withdrawals. The record of absolute gravity observations displays variations of as much as 35 microGal that correspond with local hydrologic variations documented from precipitation, streamflow, elevation, depths to water, and well pumping records. Depth to water in nearby wells display variations related to occasional local heavy precipitation events, runoff, recharge, and groundwater withdrawals. Increases in gravity that occur over periods of several months or longer correspond with occasional heavy precipitation and recharge. Periods of gravity decline occur during extended periods between recharge events and periods of increased local groundwater withdrawals. Analysis of the continuous records from both instruments indicate that groundwater drains slowly from storage in response to pumping variations, requiring several days or longer for the aquifer to drain, which is consistent with other hydrologic records.

Droplet-based magnetic bead immunoassay using microchannel-connected multiwell plates (μCHAMPs) for the detection of amyloid beta oligomers.

PubMed

Park, Min Cheol; Kim, Moojong; Lim, Gun Taek; Kang, Sung Min; An, Seong Soo A; Kim, Tae Song; Kang, Ji Yoon

2016-06-21

Multiwell plates are regularly used in analytical research and clinical diagnosis but often require laborious washing steps and large sample or reagent volumes (typically, 100 μL per well). To overcome such drawbacks in the conventional multiwell plate, we present a novel microchannel-connected multiwell plate (μCHAMP) that can be used for automated disease biomarker detection in a small sample volume by performing droplet-based magnetic bead immunoassay inside the plate. In this μCHAMP-based immunoassay platform, small volumes (30-50 μL) of aqueous-phase working droplets are stably confined within each well by the simple microchannel structure (200-300 μm in height and 0.5-1 mm in width), and magnetic beads are exclusively transported into an adjacent droplet through the oil-filled microchannels assisted by a magnet array aligned beneath and controlled by a XY-motorized stage. Using this μCHAMP-based platform, we were able to perform parallel detection of synthetic amyloid beta (Aβ) oligomers as a model analyte for the early diagnosis of Alzheimer's disease (AD). This platform easily simplified the laborious and consumptive immunoassay procedure by achieving automated parallel immunoassay (32 assays per operation in 3-well connected 96-well plate) within 1 hour and at low sample consumption (less than 10 μL per assay) with no cumbersome manual washing step. Moreover, it could detect synthetic Aβ oligomers even below 10 pg mL(-1) concentration with a calculated detection limit of ∼3 pg mL(-1). Therefore, the μCHAMP and droplet-based magnetic bead immunoassay, with the combination of XY-motorized magnet array, would be a useful platform in the diagnosis of human disease, including AD, which requires low consumption of the patient's body fluid sample and automation of the entire immunoassay procedure for high processing capacity.

VizieR Online Data Catalog: YSOs APEX-CHAMP+ high-J CO maps (Yildiz+,

NASA Astrophysics Data System (ADS)

Yildiz, U. A.; Kristensen, L. E.; van Dishoeck, E. F.; Hogerheijde, M. R.; Karska, A.; Belloche, A.; Endo, A.; Frieswijk, W.; Gusten, R.; van Kempen, T. A.; Leurini, S.; Nagy, Z.; Perez-Beaupuits, J. P.; Risacher, C.; van der Marel, N.; van Weeren, R. J.; Wyrowski, F.

2015-01-01

Files contain the observations of 12CO and 13 JCMT-HARP-B and 12CO and 13CO 6-5 from APEX-CHAMP+, toward 26 low mass protostars as listed below. The data analysis was done via GILDAS-CLASS, where raw data are processed to obtain regularly sampled data. The spectra are given in two formats; fits cube and GILDAS lmv cube. File names are self explanatory, i.e., SOURCENAMEMOLECULETRANSITIONTELESCOPENAMEcube_VELOCITYRESOLUTION.fits and SOURCENAMEMOLECULETRANSITIONTELESCOPENAMEcube_VELOCITYRESOLUTION.lmv (3 data files).

Relativité générale et gravitation.

NASA Astrophysics Data System (ADS)

Elbaz, E.

Contents: 1. Description de l'univers observable. 2. Lemicro-univers des particules élémentaires. 3. Analyse tensorielle.4. Relativité restreinte. 5. Effet de la gravitation en relativité générale. 6. Équations d'Einstein. 7. Ondes gravitationnelles. 8. Champ de gravitation statique et isotrope. 9. Structures stellaires. 10. Champ de gravitation non statique isotrope. 11. Introduction à la dynamique cosmologique et au modèle standard de l'univers très primitif. 12. Perspectives actuelles.

Recent geomagnetic secular variation from Swarm and ground observatories as estimated in the CHAOS-6 geomagnetic field model

NASA Astrophysics Data System (ADS)

Finlay, Christopher C.; Olsen, Nils; Kotsiaros, Stavros; Gillet, Nicolas; Tøffner-Clausen, Lars

2016-07-01

We use more than 2 years of magnetic data from the Swarm mission, and monthly means from 160 ground observatories as available in March 2016, to update the CHAOS time-dependent geomagnetic field model. The new model, CHAOS-6, provides information on time variations of the core-generated part of the Earth's magnetic field between 1999.0 and 2016.5. We present details of the secular variation (SV) and secular acceleration (SA) from CHAOS-6 at Earth's surface and downward continued to the core surface. At Earth's surface, we find evidence for positive acceleration of the field intensity in 2015 over a broad area around longitude 90°E that is also seen at ground observatories such as Novosibirsk. At the core surface, we are able to map the SV up to at least degree 16. The radial field SA at the core surface in 2015 is found to be largest at low latitudes under the India-South-East Asia region, under the region of northern South America, and at high northern latitudes under Alaska and Siberia. Surprisingly, there is also evidence for significant SA in the central Pacific region, for example near Hawaii where radial field SA is observed on either side of a jerk in 2014. On the other hand, little SV or SA has occurred over the past 17 years in the southern polar region. Inverting for a quasi-geostrophic core flow that accounts for this SV, we obtain a prominent planetary-scale, anti-cyclonic, gyre centred on the Atlantic hemisphere. We also find oscillations of non-axisymmetric, azimuthal, jets at low latitudes, for example close to 40°W, that may be responsible for localized SA oscillations. In addition to scalar data from Ørsted, CHAMP, SAC-C and Swarm, and vector data from Ørsted, CHAMP and Swarm, CHAOS-6 benefits from the inclusion of along-track differences of scalar and vector field data from both CHAMP and the three Swarm satellites, as well as east-west differences between the lower pair of Swarm satellites, Alpha and Charlie. Moreover, ground observatory SV estimates are fit to a Huber-weighted rms level of 3.1 nT/year for the eastward components and 3.8 and 3.7 nT/year for the vertical and southward components. We also present an update of the CHAOS high-degree lithospheric field, making use of along-track differences of CHAMP scalar and vector field data to produce a new static field model that agrees well with the MF7 field model out to degree 110.

Comparison of Selected Geopotential Models in Terms of the GOCE Orbit Determination Using Simulated GPS Observations

NASA Astrophysics Data System (ADS)

Bobojć, Andrzej

2016-12-01

This work contains a comparative study of the performance of six geopotential models in an orbit estimation process of the satellite of the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) mission. For testing, such models as ULUX_CHAMP2013S, ITG-GRACE 2010S, EIGEN-51C, EIGEN5S, EGM2008, EGM96, were adopted. Different sets of pseudo-range simulations along reference GOCE satellite orbital arcs were obtained using real orbits of the Global Positioning System satellites. These sets were the basic observation data used in the adjustment. The centimeter-accuracy Precise Science Orbit (PSO) for the GOCE satellite provided by the European Space Agency (ESA) was adopted as the GOCE reference orbit. Comparing various variants of the orbital solutions, the relative accuracy of geopotential models in an orbital aspect is determined. Full geopotential models were used in the adjustment process. The solutions were also determined taking into account truncated geopotential models. In such case, an accuracy of the solutions was slightly enhanced. Different arc lengths were taken for the computation.

Satellite observations of atmosphere-ionosphere vertical coupling by gravity waves

NASA Astrophysics Data System (ADS)

Trinh, Thai; Ern, Manfred; Preusse, Peter; Riese, Martin

2017-04-01

The Earth's thermosphere/ionosphere (T/I) is strongly influenced by various processes from above as well as from below. One of the most important processes from below is vertical coupling by atmospheric waves. Among these waves, gravity waves (GWs) excited in the lower atmosphere, mainly in the troposphere and tropopause region, are likely essential for the mean state of the T/I system. The penetration of GWs into the T/I system is however not well understood in modeling as well as observations. In this work, we analyze the correlation between different GW parameters at lower altitudes (below 90 km) and GW induced perturbations in the T/I. At lower altitudes, GW parameters are derived from temperature observations of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). In the T/I, GW induced perturbations of neutral density measured by Gravity field and Ocean Circulation Explorer (GOCE) and CHAllenging Minisatellite Payload (CHAMP) are analyzed. Interestingly, we find positive correlations between the spatial distributions at low altitudes (i.e. below 90km) and the spatial distributions of GW-induced density fluctuations in the T/I (at 200km and above), which suggests that many waves seen in the T/I have their origins in the troposphere or lower stratosphere. It is also indicated that mountain waves generated near the Andes and Antarctic Peninsula propagate up to the T/I. Strong positive correlations between GW perturbations in the T/I and GW parameters at 30 km are mainly found at mid latitudes, which may be an indicator of propagation of convectively generated GWs. Increase of correlation starting from 70 km in many cases shows that filtering of the GW distribution by the background atmosphere is very important. Processes that are likely involved are GW dissipation, generation of secondary GWs, as well as horizontal propagation of GWs. Limitations of our method and of the observations are also discussed.

Daily variation of diurnal thermal tides from CHAMP and GOCE accelerometer measurements

NASA Astrophysics Data System (ADS)

Gasperini, Federico; Doornbos, Eelco; Forbes, Jeffrey M.; Bruinsma, Sean; Haeusler, Kathrin; Hagan, Maura

Daily migrating and non-migrating diurnal tides in exospheric temperature derived from simultaneous accelerometer measurements on CHAMP (near 300 km) and GOCE (near 260 km) are studied for the intervals November-December 2009 and March-April 2010. Neutral densities are converted to exospheric temperatures using the NRLMSISe00 empirical model and by iterating on a convenient parameter (e.g. F10.7 solar flux). This methodology is validated using NCAR TIME-GCM simulations for this period as a mock data set, and results are compared to an approach where differences between ascending and descending orbital measurements are used to estimate diurnal tides for CHAMP and GOCE separately. The tidal components analyzed are the westward-propagating components with zonal wave numbers s=1 and s=2 (DW1 and DW2) and the eastward-propagating components with s=-2 and s=-3 (DE2 and DE3). Spectral analyses are used to reveal potential planetary wave modulations of the daily tidal amplitudes.

The climatology of low latitude ionospheric currents derived from CHAMP observations

NASA Astrophysics Data System (ADS)

Stolle, Claudia; Alken, Patrik

2010-05-01

The multi-year data base of magnetic field and ionospheric measurements from the CHAMP satellite contain enormous potential to investigate the behaviour and the origin of currents in the E and F region ionosphere. Special advantage is drawn from the satellite's near polar orbit and the full data coverage over all longitudes and local times. This paper will present findings about two prominent features of the low latitude ionosphere: equatorial plasma irregularities and the equatorial electrojet (EEJ). Equatorial plasma irregularities (commonly known as "bubbles") severely disturb the post sunset F region ionosphere and cause the strongest radio wave scintillations globally during solar maximum years. Using CHAMP vector magnetic field data, it was possible for the first time to show on a long term basis that equatorial plasma irregularities have signatures in all components of the magnetic field. The first ever global climatology of the occurrence rate of these magnetic signatures has been compiled. Such a data base of disturbed orbits is especially useful for core and crustal magnetic field modellers. The magnetic field observations of CHAMP, Ørsted, and SAC-C were employed to develop a climatological model of the EEJ. Measurements of the EEJ and empirical values from electron density and thermospheric density and winds have in addition enabled the development of a climatological model of the equatorial electric field. These results provide excellent opportunity to investigate the seasonal/longitudinal characteristics of the EEJ and the influence of atmospheric waves on E region dynamics.

Time Changes of the European Gravity Field from GRACE: A Comparison with Ground Measurements from Superconducting Gravimeters and with Hydrology Model Predictions

NASA Technical Reports Server (NTRS)

Hinderer, J.; Lemoine, Frank G.; Crossley, D.; Boy, J.-P.

2004-01-01

We investigate the time-variable gravity changes in Europe retrieved from the initial GRACE monthly solutions spanning a 18 month duration from April 2002 to October 2003. Gravity anomaly maps are retrieved in Central Europe from the monthly satellite solutions we compare the fields according to various truncation levels (typically between degree 10 and 20) of the initial fields (expressed in spherical harmonics to degree 120). For these different degrees, an empirical orthogonal function (EOF) decomposition of the time-variable gravity field leads us to its main spatial and temporal characteristics. We show that the dominant signal is found to be annual with an amplitude and a phase both in agreement with predictions in Europe modeled using snow and soil-moisture variations from recent hydrology models. We compare these GRACE gravity field changes to surface gravity observations from 6 superconducting gravimeters of the GGP (Global Geodynamics Project) European sub-network, with a special attention to loading corrections. Initial results suggest that all 3 data sets (GRACE, hydrology and GGP) are responding to annual changes in near-surface water in Europe of a few microGal (at length scales of approx.1000 km) that show a high value in winter and a summer minimum. We also point out that the GRACE gravity field evolution seems to indicate that there is a trend in gravity between summer 2002 and summer 2003 which can be related to the 2003 heatwave in Europe and its hydrological consequences (drought). Despite the limited time span of our analysis and the uncertainties in retrieving a regional solution from the network of gravimeters, the calibration and validation aspects of the GRACE data processing based on the annual hydrology cycle in Europe are in progress.

Combination of GRACE monthly gravity field solutions from different processing strategies

NASA Astrophysics Data System (ADS)

Jean, Yoomin; Meyer, Ulrich; Jäggi, Adrian

2018-02-01

We combine the publicly available GRACE monthly gravity field time series to produce gravity fields with reduced systematic errors. We first compare the monthly gravity fields in the spatial domain in terms of signal and noise. Then, we combine the individual gravity fields with comparable signal content, but diverse noise characteristics. We test five different weighting schemes: equal weights, non-iterative coefficient-wise, order-wise, or field-wise weights, and iterative field-wise weights applying variance component estimation (VCE). The combined solutions are evaluated in terms of signal and noise in the spectral and spatial domains. Compared to the individual contributions, they in general show lower noise. In case the noise characteristics of the individual solutions differ significantly, the weighted means are less noisy, compared to the arithmetic mean: The non-seasonal variability over the oceans is reduced by up to 7.7% and the root mean square (RMS) of the residuals of mass change estimates within Antarctic drainage basins is reduced by 18.1% on average. The field-wise weighting schemes in general show better performance, compared to the order- or coefficient-wise weighting schemes. The combination of the full set of considered time series results in lower noise levels, compared to the combination of a subset consisting of the official GRACE Science Data System gravity fields only: The RMS of coefficient-wise anomalies is smaller by up to 22.4% and the non-seasonal variability over the oceans by 25.4%. This study was performed in the frame of the European Gravity Service for Improved Emergency Management (EGSIEM; http://www.egsiem.eu) project. The gravity fields provided by the EGSIEM scientific combination service (ftp://ftp.aiub.unibe.ch/EGSIEM/) are combined, based on the weights derived by VCE as described in this article.

Ontogeny of mouse vestibulo-ocular reflex following genetic or environmental alteration of gravity sensing.

PubMed

Beraneck, Mathieu; Bojados, Mickael; Le Séac'h, Anne; Jamon, Marc; Vidal, Pierre-Paul

2012-01-01

The vestibular organs consist of complementary sensors: the semicircular canals detect rotations while the otoliths detect linear accelerations, including the constant pull of gravity. Several fundamental questions remain on how the vestibular system would develop and/or adapt to prolonged changes in gravity such as during long-term space journey. How do vestibular reflexes develop if the appropriate assembly of otoliths and semi-circular canals is perturbed? The aim of present work was to evaluate the role of gravity sensing during ontogeny of the vestibular system. In otoconia-deficient mice (ied), gravity cannot be sensed and therefore maculo-ocular reflexes (MOR) were absent. While canals-related reflexes were present, the ied deficit also led to the abnormal spatial tuning of the horizontal angular canal-related VOR. To identify putative otolith-related critical periods, normal C57Bl/6J mice were subjected to 2G hypergravity by chronic centrifugation during different periods of development or adulthood (Adult-HG) and compared to non-centrifuged (control) C57Bl/6J mice. Mice exposed to hypergravity during development had completely normal vestibulo-ocular reflexes 6 months after end of centrifugation. Adult-HG mice all displayed major abnormalities in maculo-ocular reflexe one month after return to normal gravity. During the next 5 months, adaptation to normal gravity occurred in half of the individuals. In summary, genetic suppression of gravity sensing indicated that otolith-related signals might be necessary to ensure proper functioning of canal-related vestibular reflexes. On the other hand, exposure to hypergravity during development was not sufficient to modify durably motor behaviour. Hence, 2G centrifugation during development revealed no otolith-specific critical period.

Ontogeny of Mouse Vestibulo-Ocular Reflex Following Genetic or Environmental Alteration of Gravity Sensing

PubMed Central

Beraneck, Mathieu; Bojados, Mickael; Le Séac’h, Anne; Jamon, Marc; Vidal, Pierre-Paul

2012-01-01

The vestibular organs consist of complementary sensors: the semicircular canals detect rotations while the otoliths detect linear accelerations, including the constant pull of gravity. Several fundamental questions remain on how the vestibular system would develop and/or adapt to prolonged changes in gravity such as during long-term space journey. How do vestibular reflexes develop if the appropriate assembly of otoliths and semi-circular canals is perturbed? The aim of present work was to evaluate the role of gravity sensing during ontogeny of the vestibular system. In otoconia-deficient mice (ied), gravity cannot be sensed and therefore maculo-ocular reflexes (MOR) were absent. While canals-related reflexes were present, the ied deficit also led to the abnormal spatial tuning of the horizontal angular canal-related VOR. To identify putative otolith-related critical periods, normal C57Bl/6J mice were subjected to 2G hypergravity by chronic centrifugation during different periods of development or adulthood (Adult-HG) and compared to non-centrifuged (control) C57Bl/6J mice. Mice exposed to hypergravity during development had completely normal vestibulo-ocular reflexes 6 months after end of centrifugation. Adult-HG mice all displayed major abnormalities in maculo-ocular reflexe one month after return to normal gravity. During the next 5 months, adaptation to normal gravity occurred in half of the individuals. In summary, genetic suppression of gravity sensing indicated that otolith-related signals might be necessary to ensure proper functioning of canal-related vestibular reflexes. On the other hand, exposure to hypergravity during development was not sufficient to modify durably motor behaviour. Hence, 2G centrifugation during development revealed no otolith-specific critical period. PMID:22808156

Validation of the EGSIEM combined monthly GRACE gravity fields

NASA Astrophysics Data System (ADS)

Li, Zhao; van Dam, Tonie; Chen, Qiang; Weigelt, Matthias; Güntner, Andreas; Jäggi, Adrian; Meyer, Ulrich; Jean, Yoomin; Altamimi, Zuheir; Rebischung, Paul

2016-04-01

Observations indicate that global warming is affecting the water cycle. Here in Europe predictions are for more frequent high precipitation events, wetter winters, and longer and dryer summers. The consequences of these changes include the decreasing availability of fresh water resources in some regions as well as flooding and erosion of coastal and low-lying areas in other regions. These weather related effects impose heavy costs on society and the economy. We cannot stop the immediate effects global warming on the water cycle. But there may be measures that we can take to mitigate the costs to society. The Horizon2020 supported project, European Gravity Service for Improved Emergency Management (EGSIEM), will add value to EO observations of variations in the Earth's gravity field. In particular, the EGSIEM project will interpret the observations of gravity field changes in terms of changes in continental water storage. The project team will develop tools to alert the public water storage conditions could indicate the onset of regional flooding or drought. As part of the EGSIEM project, a combined GRACE gravity product is generated, using various monthly GRACE solutions from associated processing centers (ACs). Since each AC follows a set of common processing standards but applies its own independent analysis method, the quality, robustness, and reliability of the monthly combined gravity fields should be significantly improved as compared to any individual solution. In this study, we present detailed and updated comparisons of the combined EGSIEM GRACE gravity product with GPS position time series, hydrological models, and existing GRACE gravity fields. The GPS residuals are latest REPRO2 station position residuals, obtained by rigorously stacking the IGS Repro 2 , daily solutions, estimating, and then restoring the annual and semi-annual signals.

Comparison of precision orbit derived density estimates for CHAMP and GRACE satellites

NASA Astrophysics Data System (ADS)

Fattig, Eric Dale

Current atmospheric density models cannot adequately represent the density variations observed by satellites in Low Earth Orbit (LEO). Using an optimal orbit determination process, precision orbit ephemerides (POE) are used as measurement data to generate corrections to density values obtained from existing atmospheric models. Densities obtained using these corrections are then compared to density data derived from the onboard accelerometers of satellites, specifically the CHAMP and GRACE satellites. This comparison takes two forms, cross correlation analysis and root mean square analysis. The densities obtained from the POE method are nearly always superior to the empirical models, both in matching the trends observed by the accelerometer (cross correlation), and the magnitudes of the accelerometer derived density (root mean square). In addition, this method consistently produces better results than those achieved by the High Accuracy Satellite Drag Model (HASDM). For satellites orbiting Earth that pass through Earth's upper atmosphere, drag is the primary source of uncertainty in orbit determination and prediction. Variations in density, which are often not modeled or are inaccurately modeled, cause difficulty in properly calculating the drag acting on a satellite. These density variations are the result of many factors; however, the Sun is the main driver in upper atmospheric density changes. The Sun influences the densities in Earth's atmosphere through solar heating of the atmosphere, as well as through geomagnetic heating resulting from the solar wind. Data are examined for fourteen hour time spans between November 2004 and July 2009 for both the CHAMP and GRACE satellites. This data spans all available levels of solar and geomagnetic activity, which does not include data in the elevated and high solar activity bins due to the nature of the solar cycle. Density solutions are generated from corrections to five different baseline atmospheric models, as well as nine combinations of density and ballistic coefficient correlated half-lives. These half-lives are varied among values of 1.8, 18, and 180 minutes. A total of forty-five sets of results emerge from the orbit determination process for all combinations of baseline density model and half-lives. Each time period is examined for both CHAMP and GRACE-A, and the results are analyzed. Results are averaged from all solutions periods for 2004--2007. In addition, results are averaged after binning according to solar and geomagnetic activity levels. For any given day in this period, a ballistic coefficient correlated half-life of 1.8 minutes yields the best correlation and root mean square values for both CHAMP and GRACE. For CHAMP, a density correlated half-life of 18 minutes is best for higher levels of solar and geomagnetic activity, while for lower levels 180 minutes is usually superior. For GRACE, 180 minutes is nearly always best. The three Jacchia-based atmospheric models yield very similar results. The CIRA 1972 or Jacchia 1971 models as baseline consistently produce the best results for both satellites, though results obtained for Jacchia-Roberts are very similar to the other Jacchia-based models. Data are examined in a similar manner for the extended solar minimum period during 2008 and 2009, albeit with a much smaller sampling of data. With the exception of some atypical results, similar combinations of half-lives and baseline atmospheric model produce the best results. A greater sampling of data will aid in characterizing density in a period of especially low solar activity. In general, cross correlation values for CHAMP and GRACE revealed that the POE method matched trends observed by the accelerometers very well. However, one period of time deviated from this trend for the GRACE-A satellite. Between late October 2005 and January 2006, correlations for GRACE-A were very low. Special examination of the surrounding months revealed the extent of time this period covered. Half-life and baseline model combinations that produced the best results during this time were similar to those during normal periods. Plotting these periods revealed very short period density variations in the accelerometer that could not be reproduced by the empirical models, HASDM, or the POE method. Finally, densities produced using precision orbit data for the GRACE-B satellite were shown to be nearly indistinguishable from those produced by GRACE-A. Plots of the densities produced for both satellites during the same time periods revealed this fact. Multiple days were examined covering all possible ranges of solar and geomagnetic activity. In addition, the period in which GRACE-A correlations were low was studied. No significant differences existed between GRACE-A and GRACE-B for all of the days examined.

GPS-Based Reduced Dynamic Orbit Determination Using Accelerometer Data

NASA Technical Reports Server (NTRS)

VanHelleputte, Tom; Visser, Pieter

2007-01-01

Currently two gravity field satellite missions, CHAMP and GRACE, are equipped with high sensitivity electrostatic accelerometers, measuring the non-conservative forces acting on the spacecraft in three orthogonal directions. During the gravity field recovery these measurements help to separate gravitational and non-gravitational contributions in the observed orbit perturbations. For precise orbit determination purposes all these missions have a dual-frequency GPS receiver on board. The reduced dynamic technique combines the dense and accurate GPS observations with physical models of the forces acting on the spacecraft, complemented by empirical accelerations, which are stochastic parameters adjusted in the orbit determination process. When the spacecraft carries an accelerometer, these measured accelerations can be used to replace the models of the non-conservative forces, such as air drag and solar radiation pressure. This approach is implemented in a batch least-squares estimator of the GPS High Precision Orbit Determination Software Tools (GHOST), developed at DLR/GSOC and DEOS. It is extensively tested with data of the CHAMP and GRACE satellites. As accelerometer observations typically can be affected by an unknown scale factor and bias in each measurement direction, they require calibration during processing. Therefore the estimated state vector is augmented with six parameters: a scale and bias factor for the three axes. In order to converge efficiently to a good solution, reasonable a priori values for the bias factor are necessary. These are calculated by combining the mean value of the accelerometer observations with the mean value of the non-conservative force models and empirical accelerations, estimated when using these models. When replacing the non-conservative force models with accelerometer observations and still estimating empirical accelerations, a good orbit precision is achieved. 100 days of GRACE B data processing results in a mean orbit fit of a few centimeters with respect to high-quality JPL reference orbits. This shows a slightly better consistency compared to the case when using force models. A purely dynamic orbit, without estimating empirical accelerations thus only adjusting six state parameters and the bias and scale factors, gives an orbit fit for the GRACE B test case below the decimeter level. The in orbit calibrated accelerometer observations can be used to validate the modelled accelerations and estimated empirical accelerations computed with the GHOST tools. In along track direction they show the best resemblance, with a mean correlation coefficient of 93% for the same period. In radial and normal direction the correlation is smaller. During days of high solar activity the benefit of using accelerometer observations is clearly visible. The observations during these days show fluctuations which the modelled and empirical accelerations can not follow.

Influence of gravity on foams

NASA Astrophysics Data System (ADS)

Monnereau, C.; Vignes-Adler, M.; Kronberg, B.

1999-06-01

The feasibility of experiments on the physics of foams in microgravity environment was investigated during a parabolic flight campaign. Transient foams from surfactant-free organic liquids and stable foams from a soapy solution of a Sodium Dodecyl Sulfate + Dodecanol mixture were investigated. In 0g, the transient foam is stabilized; whatever the liquid the foam bubbles are spherical and their diameter does not change during the flight. When the gravity constant is equal to 1.8 g, the bubbles of the stable foam become polyhedral and numerous topological transformations could be observed. La faisabilité d'expériences permettant d'étudier la physique de la mousse en microgravité a été démontrée au cours de vols paraboliques. Nous avons testé des mousses de liquides organiques sans tensioactif qui sont éphémères dans le champ terrestre, et des mousses à base d'une solution aqueuse d'un mélange de Dodécyl Sulfate de Sodium et de Dodécanol qui sont au contraire très stables. En microgravité, les mousses éphémères sont stabilisées; quel que soit le liquide, les bulles sont sphériques et leur diamètre reste égal à leur valeur initiale. Lorsqu'au cours de la parabole, la gravité devient égale à 1,8 g, les bulles de la mousse stable dont les films sont très rigides prennent une forme polyédrique ; de très nombreuses transformations topologiques de type T1 ont pu alors être observées.

43 CFR 3103.4-3 - Heavy oil royalty reductions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... must certify that the API oil gravity for the initial and subsequent 12-month periods was not subject... reduction for a property if BLM determines that the API oil gravity was manipulated or adulterated by the... effective date of the royalty rate reduction resulting from a manipulated or adulterated API oil gravity so...

43 CFR 3103.4-3 - Heavy oil royalty reductions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... must certify that the API oil gravity for the initial and subsequent 12-month periods was not subject... reduction for a property if BLM determines that the API oil gravity was manipulated or adulterated by the... effective date of the royalty rate reduction resulting from a manipulated or adulterated API oil gravity so...

43 CFR 3103.4-3 - Heavy oil royalty reductions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... must certify that the API oil gravity for the initial and subsequent 12-month periods was not subject... reduction for a property if BLM determines that the API oil gravity was manipulated or adulterated by the... effective date of the royalty rate reduction resulting from a manipulated or adulterated API oil gravity so...

43 CFR 3103.4-3 - Heavy oil royalty reductions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... must certify that the API oil gravity for the initial and subsequent 12-month periods was not subject... reduction for a property if BLM determines that the API oil gravity was manipulated or adulterated by the... effective date of the royalty rate reduction resulting from a manipulated or adulterated API oil gravity so...

Annual Report of the Chief, National Guard Bureau for the Fiscal Year 1971

DTIC Science & Technology

1971-06-30

caaBKinan nicnaKs «a as $mm KI K oriiiims m nriiws liflSIW KI 00 msoHii imsM •» o» 13 J Army CHAMPS Team Handball In January 1971 the Army CHAMPS...the sport of team handball in the United States which would provide a talent base from which to draw players for the U.S. Olympic Team. These... handball . Domestic Action National Guard Domestic Action programs, designed to alleviate social problems within communities throughout the United States

Interpretation of CHAMP Magnetic Anomaly Data over the Pannonian Basin Region Using Lower Altitude Horizontal Gradient Data

NASA Technical Reports Server (NTRS)

Taylor, P. T.; Kis, K. I.; Wittmann, G.

2013-01-01

The ESA SWARM mission will have three earth orbiting magnetometer bearing satellites one in a high orbit and two side-by-side in lower orbits. These latter satellites will record a horizontal magnetic gradient. In order to determine how we can use these gradient measurements for interpretation of large geologic units we used ten years of CHAMP data to compute a horizontal gradient map over a section of southeastern Europe with our goal to interpret these data over the Pannonian Basin of Hungary.

Time-variable gravity fields and ocean mass change from 37 months of kinematic Swarm orbits

NASA Astrophysics Data System (ADS)

Lück, Christina; Kusche, Jürgen; Rietbroek, Roelof; Löcher, Anno

2018-03-01

Measuring the spatiotemporal variation of ocean mass allows for partitioning of volumetric sea level change, sampled by radar altimeters, into mass-driven and steric parts. The latter is related to ocean heat change and the current Earth's energy imbalance. Since 2002, the Gravity Recovery and Climate Experiment (GRACE) mission has provided monthly snapshots of the Earth's time-variable gravity field, from which one can derive ocean mass variability. However, GRACE has reached the end of its lifetime with data degradation and several gaps occurred during the last years, and there will be a prolonged gap until the launch of the follow-on mission GRACE-FO. Therefore, efforts focus on generating a long and consistent ocean mass time series by analyzing kinematic orbits from other low-flying satellites, i.e. extending the GRACE time series. Here we utilize data from the European Space Agency's (ESA) Swarm Earth Explorer satellites to derive and investigate ocean mass variations. For this aim, we use the integral equation approach with short arcs (Mayer-Gürr, 2006) to compute more than 500 time-variable gravity fields with different parameterizations from kinematic orbits. We investigate the potential to bridge the gap between the GRACE and the GRACE-FO mission and to substitute missing monthly solutions with Swarm results of significantly lower resolution. Our monthly Swarm solutions have a root mean square error (RMSE) of 4.0 mm with respect to GRACE, whereas directly estimating constant, trend, annual, and semiannual (CTAS) signal terms leads to an RMSE of only 1.7 mm. Concerning monthly gaps, our CTAS Swarm solution appears better than interpolating existing GRACE data in 13.5 % of all cases, when artificially removing one solution. In the case of an 18-month artificial gap, 80.0 % of all CTAS Swarm solutions were found closer to the observed GRACE data compared to interpolated GRACE data. Furthermore, we show that precise modeling of non-gravitational forces acting on the Swarm satellites is the key for reaching these accuracies. Our results have implications for sea level budget studies, but they may also guide further research in gravity field analysis schemes, including satellites not dedicated to gravity field studies.

Capturing the fingerprint of Etna volcano activity in gravity and satellite radar data

PubMed Central

Negro, Ciro Del; Currenti, Gilda; Solaro, Giuseppe; Greco, Filippo; Pepe, Antonio; Napoli, Rosalba; Pepe, Susi; Casu, Francesco; Sansosti, Eugenio

2013-01-01

Long-term and high temporal resolution gravity and deformation data move us toward a better understanding of the behavior of Mt Etna during the June 1995 – December 2011 period in which the volcano exhibited magma charging phases, flank eruptions and summit crater activity. Monthly repeated gravity measurements were coupled with deformation time series using the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique on two sequences of interferograms from ERS/ENVISAT and COSMO-SkyMed satellites. Combining spatiotemporal gravity and DInSAR observations provides the signature of three underlying processes at Etna: (i) magma accumulation in intermediate storage zones, (ii) magmatic intrusions at shallow depth in the South Rift area, and (iii) the seaward sliding of the volcano's eastern flank. Here we demonstrate the strength of the complementary gravity and DInSAR analysis in discerning among different processes and, thus, in detecting deep magma uprising in months to years before the onset of a new Etna eruption. PMID:24169569

A robust platform based on ultra-high performance liquid chromatography Quadrupole time of flight tandem mass spectrometry with a two-step data mining strategy in the investigation, classification, and identification of chlorogenic acids in Ainsliaea fragrans Champ.

PubMed

Ouyang, Hui; Li, Junmao; Wu, Bei; Zhang, Xiaoyong; Li, Yan; Yang, Shilin; He, Mingzhen; Feng, Yulin

2017-06-16

The chlorogenic acids are the major bioactive constituents of the whole plant of Ainsliaea fragrans Champ. (Xingxiang Tuerfeng). These compounds are usually present as isomeric forms in Xingxiang Tuerfeng. Therefore, an efficient approach should be developed for the rapid discovery and identification of chlorogenic acids isomers through the fragmentation pathway and rules. In this study, the collision induced dissociation tandem mass spectrometry (CID-MS/MS) fragmentation routes of chlorogenic acids were systematically investigated by UHPLC-QTOF-MS/MS in the negative ion mode using eight chlorogenic acids standards. As a result, diagnostic product ions for rapid discovery and classification of chlorogenic acids isomers were determined according to their MS/MS fragmentation patterns and intensity analysis. Based on these findings, a novel two-step data mining strategy was established. The first key step was to screen different kinds of substitution and the skeleton of the quinic acid using the characteristic product ions and neutral losses. The second key step was to screen and classify different types of chlorogenic acids using their diagnostic product ions. It was apply to the rapid investigation, classification, and identification of chlorogenic acids. And the same carbon skeletons from a complex extract of Ainsliaea fragrans Champ. were effectively identified. 88 constituents, including 14 chlorogenic acids types, were rapidly discovered and identified, and in particular, 12 types of chlorogenic acids, including p-CoQC, FQA, BQC, CQA-Glu, CFQA, p-Co-CQC, di-p-CoQC, BCQA, di-CQA-Glu, PCQA, tri-QCA, and P-di-CQA, were first discovered in Ainsliaea fragrans Champ. In conclusion, UHPLC-QTOF-MS/MS method together with a systematic two-step data mining strategy was established as a feasible, effective, and rational technique for analyzing chlorogenic acids. Additionally, this study laid a foundation for the study of the active substances and quality control of Ainsliaea fragrans Champ. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of the Crust of the Pannonian Basin, Hungary Using Low-Altitude CHAMP Horizontal Gradient Magnetic Anomalies

NASA Technical Reports Server (NTRS)

Taylor, Patrick T.; Kis, Karoly I.; Puszta, Sandor; Wittmann, Geza; Kim, Hyung Rae; Toronyi, B.

2011-01-01

The Pannonian Basin is a deep intra-continental basin that formed as part of the Alpine orogeny. It is some 600 by 500 km in area and centered on Hungary. This area was chosen since it has one of the thinnest continental crusts in Europe and is the region of complex tectonic structures. In order to study the nature of the crustal basement we used the long-wavelength magnetic anomalies acquired by the CHAMP satellite. The SWARM constellation, scheduled to be launched next year, will have two lower altitude satellites flying abreast, with a separation of between ca. 150 to 200 km. to record the horizontal magnetic gradient. Since the CHAMP satellite has been in orbit for eight years and has obtained an extensive range of data, both vertically and horizontally there is a large enough data base to compute the horizontal magnetic gradients over the Pannonian Basin region using these many CHAMP orbits. We recomputed a satellite magnetic anomaly map, using the spherical-cap method of Haines (1985), the technique of Alsdorf et al. (1994) and from spherical harmonic coefficients of MF6 (Maus et aI., 2008) employing the latest and lowest altitude CHAMP data. We then computed the horizontal magnetic anomaly gradients (Kis and Puszta, 2006) in order to determine how these component data will improve our interpretation and to preview what the SW ARM mission will reveal with reference to the horizontal gradient anomalies. The gradient amplitude of an 1000 km northeast-southwest profile through our horizontal component anomaly map varied from 0 to 0.025 nT/km with twin positive anomalies (0.025 and 0.023 nT/km) separated by a sharp anomaly negative at o nT/km. Horizontal gradient indicate major magnetization boundaries in the crust (Dole and Jordan, 1978 and Cordell and Grauch, 1985). Our gradient anomaly was modeled with a twodimensional body and the anomaly, of some 200 km, correlates with a 200 km area of crustal thinning in the southwestern Pannonian Basin.

CogChamps - a model of implementing evidence-based care in hospitals: study protocol.

PubMed

Travers, Catherine; Graham, Frederick; Henderson, Amanda; Beattie, Elizabeth

2017-03-14

Delirium and dementia (cognitive impairment; CI), are common in older hospital patients, and both are associated with serious adverse outcomes. Despite delirium often being preventable, it is frequently not recognized in hospital settings, which may be because hospital nurses have not received adequate education or training in recognizing or caring for those with CI. However, the most effective way of increasing nurses' awareness about delirium and dementia, and initiating regular patient screening and monitoring to guide best practices for these patients in hospital settings is not known. Hence this current project, conducted in 2015-2017, aims to redress this situation by implementing a multi-component non-pharmacological evidence-based intervention for patients with CI, through educating and mentoring hospital nurses to change their practice. The development of the practice change component is informed by recent findings from implementation science that focuses on facilitation as the active ingredient in knowledge uptake and utilization. This component focuses on educating and empowering experienced nurses to become Cognition Champions (CogChamps) across six wards in a large Australian tertiary referral hospital. The CogChamps will, in turn, educate other nursing team members to more effectively care for patients with CI. The hospital leadership team are supportive of the project and are directly involved in selecting the CogChamps. CogChamps will be provided with comprehensive education in evidence-based delirium assessment, prevention and management, and practice change management skills. They will receive continuing support from research and education staff about raising awareness, upskilling other staff in delirium assessment and in the adoption of best practices for preventing and managing delirium. Both qualitative and quantitative data are being collected at multiple time-points to evaluate process, impact and outcome, and to provide clarity regarding the most effective aspects of the intervention. This paper describes the study protocol for the implementation of multi-component evidence-based non-pharmacological practices designed to improve the care of older hospital patients with CI. Findings will inform subsequent initiatives directed towards enhancing the capacity of the nursing workforce to implement best practices for providing high quality care for this growing patient population throughout their acute care hospital stay.

Academic medicine: a key partner in strengthening the primary care infrastructure via teaching health centers.

PubMed

Rieselbach, Richard E; Crouse, Byron J; Neuhausen, Katherine; Nasca, Thomas J; Frohna, John G

2013-12-01

In the United States, a worsening shortage of primary care physicians, along with structural deficiencies in their training, threaten the primary care system that is essential to ensuring access to high-quality, cost-effective health care. Community health centers (CHCs) are an underused resource that could facilitate rapid expansion of the primary care workforce and simultaneously prepare trainees for 21st-century practice. The Teaching Health Center Graduate Medical Education (THCGME) program, currently funded by the Affordable Care Act, uses CHCs as training sites for primary-care-focused graduate medical education (GME).The authors propose that the goals of the THCGME program could be amplified by fostering partnerships between CHCs and teaching hospitals (academic medical centers [AMCs]). AMCs would encourage their primary care residency programs to expand by establishing teaching health center (THC) tracks. Modifications to the current THCGME model, facilitated by formal CHC and academic medicine partnerships (CHAMPs), would address the primary care physician shortage, produce physicians prepared for 21st-century practice, expose trainees to interprofessional education in a multidisciplinary environment, and facilitate the rapid expansion of CHC capacity.To succeed, CHAMP THCs require a comprehensive consortium agreement designed to ensure equity between the community and academic partners; conforming with this agreement will provide the high-quality GME necessary to ensure residency accreditation. CHAMP THCs also require a federal mechanism to ensure stable, long-term funding. CHAMP THCs would develop in select CHCs that desire a partnership with AMCs and have capacity for providing a community-based setting for both GME and health services research.

Etudes diélectriques de la transition ferroélectrique induite par application d'un champ électrique dans les céramiques PbMg{1/3}Nb{2/3}O3 (PMN)

NASA Astrophysics Data System (ADS)

Chabin, M.; Malki, M.; Husson, E.; Morell, A.

1994-07-01

The evolution of the dielectric permittivity and loss factor under an external applied electric field has been studied in PbMg{1/3}Nb{2/3}O3 ceramics between 80 and 420 K. For a threshold field of 4 kV.cm^{-1}, it is possible to induce a ferroelectric transition from the average cubic phase to a macroscopically polar phase. The poling and depoling temperatures depend on the various combinations of thermal treatments and on the applied field strength. The transition between the nanopolar state and the macropolar state is discussed L'évolution de la permittivité diélectrique et du facteur de pertes diélectriques sous un champ électrique extérieur a été étudiée dans des céramiques de PbMg{1/3}Nb{2/3}O3 enre 80 et 420 K. Pour un champ de seuil de 4 kV.cm^{-1} il est possible d'induire une transition ferroélectrique de la phase cubique moyenne en une phase macroscopiquement polaire. Les températures de polarisation et de dépolarisation dépendent des différentes combinaisons de traitements thermiques et de la valeur du champ appliqué. La transition entre la phase constituée de nanodomaines polaires et la phase constituée de macrodomaines polaires est discutée.

Modélisation du champ magnétique d'un propulseur M.H.D. annulaire

NASA Astrophysics Data System (ADS)

Kom, C. H.; Brunet, Y.

1995-01-01

Stray fields have to be as small as possible to reduce the magnetic signature of the vessel in M.H.D. propulsion where the magnetic field has to be very high. The calculation of the magnetic field of an angular M.H.D. thruster is presented. The field is produced by a distribution of superconducting magnets in the shape of sectors. An analytical formulation of the field can be used in the active zone, outside the coil ends. An analytical method using a Fourier development of the current sheets is employed for an inductor in cylindrical sectors, and a direct method is used for a massive inductor. Numerical and analytical results are compared. Pour des raisons de discrétion, les champs de fuite doivent être minimisés en propulsion M.H.D. où les champs magnétiques doivent être intenses. Le calcul du champ magnétique d'un propulseur M.H.D. naval annulaire, constitué de secteurs inducteurs supraconducteurs est représenté. Dans la zone active, hors des têtes de bobines, une formulation analytique peut être utilisée. Une méthode analytique utilisant le développemment en série de Fourier du courant est adoptée pour les industeurs cylindriques, et une méthode directe pour les inducteurs massifs. Les résultats numériques sont comparés à ceux obtenus avec un logiciel d'éléments finis 2D.

VizieR Online Data Catalog: ChaMP. I. First X-ray source catalog (Kim+, 2004)

NASA Astrophysics Data System (ADS)

Kim, D.-W.; Cameron, R. A.; Drake, J. J.; Evans, N. R.; Freeman, P.; Gaetz, T. J.; Ghosh, H.; Green, P. J.; Harnden, F. R. Jr; Karovska, M.; Kashyap, V.; Maksym, P. W.; Ratzlaff, P. W.; Schlegel, E. M.; Silverman, J. D.; Tananbaum, H. D.; Vikhlinin, A. A.; Wilkes, B. J.; Grimes, J. P.

2004-01-01

The Chandra Multiwavelength Project (ChaMP) is a wide-area (~14deg2 < survey of serendipitous Chandra X-ray sources, aiming to establish fair statistical samples covering a wide range of characteristics (such as absorbed active galactic nuclei, high-z clusters of galaxies) at flux levels (fX~10-15 to 10-14erg/s/cm2) ) intermediate between the Chandra deep surveys and previous missions. We present the first ChaMP catalog, which consists of 991 near on-axis, bright X-ray sources obtained from the initial sample of 62 observations. The data have been uniformly reduced and analyzed with techniques specifically developed for the ChaMP and then validated by visual examination. To assess source reliability and positional uncertainty, we perform a series of simulations and also use Chandra data to complement the simulation study. The false source detection rate is found to be as good as or better than expected for a given limiting threshold. On the other hand, the chance of missing a real source is rather complex, depending on the source counts, off-axis distance (or PSF), and background rate. The positional error (95% confidence level) is usually less than 1" for a bright source, regardless of its off-axis distance, while it can be as large as 4" for a weak source (~20counts) at a large off-axis distance (Doff-axis>8'). We have also developed new methods to find spatially extended or temporary variable sources, and those sources are listed in the catalog. (5 data files).

The ITSG-Grace2014 Gravity Field Model

NASA Astrophysics Data System (ADS)

Kvas, Andreas; Mayer-Gürr, Torsten; Zehenter, Norbert; Klinger, Beate

2015-04-01

The ITSG-Grace2014 GRACE-only gravity field model consists of a high resolution unconstrained static model (up to degree 200) with trend and annual signal, monthly unconstrained solutions with different spatial resolutions as well as daily snapshots derived by using a Kalman smoother. Apart from the estimated spherical harmonic coefficients, full variance-covariance matrices for the monthly solutions and the static gravity field component are provided. Compared to the previous release, multiple improvements in the processing chain are implemented: updated background models, better ionospheric modeling for GPS observations, an improved satellite attitude by combination of star camera and angular accelerations, estimation of K-band antenna center variations within the gravity field recovery process as well as error covariance function determination. Furthermore, daily gravity field variations have been modeled in the adjustment process to reduce errors caused by temporal leakage. This combined estimation of daily gravity variations field variations together with the static gravity field component represents a computational challenge due to the significantly increased parameter count. The modeling of daily variations up to a spherical harmonic degree of 40 for the whole GRACE observation period results in a system of linear equations with over 6 million unknown gravity field parameters. A least squares adjustment of this size is not solvable in a sensible time frame, therefore measures to reduce the problem size have to be taken. The ITSG-Grace2014 release is presented and selected parts of the processing chain and their effect on the estimated gravity field solutions are discussed.

Temporal gravity field modeling based on least square collocation with short-arc approach

NASA Astrophysics Data System (ADS)

ran, jiangjun; Zhong, Min; Xu, Houze; Liu, Chengshu; Tangdamrongsub, Natthachet

2014-05-01

After the launch of the Gravity Recovery And Climate Experiment (GRACE) in 2002, several research centers have attempted to produce the finest gravity model based on different approaches. In this study, we present an alternative approach to derive the Earth's gravity field, and two main objectives are discussed. Firstly, we seek the optimal method to estimate the accelerometer parameters, and secondly, we intend to recover the monthly gravity model based on least square collocation method. The method has been paid less attention compared to the least square adjustment method because of the massive computational resource's requirement. The positions of twin satellites are treated as pseudo-observations and unknown parameters at the same time. The variance covariance matrices of the pseudo-observations and the unknown parameters are valuable information to improve the accuracy of the estimated gravity solutions. Our analyses showed that introducing a drift parameter as an additional accelerometer parameter, compared to using only a bias parameter, leads to a significant improvement of our estimated monthly gravity field. The gravity errors outside the continents are significantly reduced based on the selected set of the accelerometer parameters. We introduced the improved gravity model namely the second version of Institute of Geodesy and Geophysics, Chinese Academy of Sciences (IGG-CAS 02). The accuracy of IGG-CAS 02 model is comparable to the gravity solutions computed from the Geoforschungszentrum (GFZ), the Center for Space Research (CSR) and the NASA Jet Propulsion Laboratory (JPL). In term of the equivalent water height, the correlation coefficients over the study regions (the Yangtze River valley, the Sahara desert, and the Amazon) among four gravity models are greater than 0.80.

Exploiting the Modified Colombo-Nyquist Rule for Co-estimating Sub-monthly Gravity Field Solutions from a GRACE-like Mission

NASA Astrophysics Data System (ADS)

Devaraju, B.; Weigelt, M.; Mueller, J.

2017-12-01

In order to suppress the impact of aliasing errors on the standard monthly GRACE gravity-field solutions, co-estimating sub-monthly (daily/two-day) low-degree solutions has been suggested as a solution. The maximum degree of the low-degree solutions is chosen via the Colombo-Nyquist rule of thumb. However, it is now established that the sampling of satellites puts a restriction on the maximum estimable order and not the degree - modified Colombo-Nyquist rule. Therefore, in this contribution, we co-estimate low-order sub-monthly solutions, and compare and contrast them with the low-degree sub-monthly solutions. We also investigate their efficacies in dealing with aliasing errors.

Astronaut George Nelson working on Comet Halley Active monitoring program

NASA Image and Video Library

1986-01-14

61C-05-026 (14 Jan. 1986) --- Astronaut George D. Nelson smiles for a fellow crew man's 35mm camera exposure while participating in the Comet Halley active monitoring program (CHAMP). Camera equipment and a protective shroud used to eliminate all cabin light interference surround the mission specialist. This is the first of three 1986 missions which are scheduled to monitor the rare visit by the comet. The principal investigators for CHAMP are S. Alan Stern of the Laboratory for Atmospheric and Space Physics at the University of Colorado; and Dr. Stephen Mende of Lockheed Palo Alto Research Laboratory.

Orbit error characteristic and distribution of TLE using CHAMP orbit data

NASA Astrophysics Data System (ADS)

Xu, Xiao-li; Xiong, Yong-qing

2018-02-01

Space object orbital covariance data is required for collision risk assessments, but publicly accessible two line element (TLE) data does not provide orbital error information. This paper compared historical TLE data and GPS precision ephemerides of CHAMP to assess TLE orbit accuracy from 2002 to 2008, inclusive. TLE error spatial variations with longitude and latitude were calculated to analyze error characteristics and distribution. The results indicate that TLE orbit data are systematically biased from the limited SGP4 model. The biases can reach the level of kilometers, and the sign and magnitude are correlate significantly with longitude.

Comparaison des Champs de Pression Instationnaires Calcules et Mesures sur le Modele ZKP (Comparison of Unstable Pressure Fields Calculated and Measured on the ZKP Model),

DTIC Science & Technology

1980-08-01

bord de fuite. Le nombre de Mach Man’est donc d~fini qu’entre deux limites et seule I’expdrience peut nous permettre de ...Si ion consid~re lea valeurs de Ia portance at du moment quart avant pour ce cas on obtient le tableau suivant: CC rsn Module Phase Module Phase P.P.T...Comparaison des Champs de Pression Instationnaires Calcules et Mesures sur le Mod ele ZK P COMPARISON OF UNSTABLE PRESSURE FIELDS .- %P, CALCULATED

On the possible use of radio occultation middle latitude electron density profiles to retrieve thermospheric parameters

NASA Astrophysics Data System (ADS)

Mikhailov, Andrei V.; Belehaki, Anna; Perrone, Loredanna; Zolesi, Bruno; Tsagouri, Ioanna

2014-04-01

This paper investigates possible use of middle latitude daytime COSMIC and CHAMP ionospheric radio occultation (IRO) electron density profiles (EDPs) to retrieve thermospheric parameters, based on the Mikhailov et al. (2012) method. The aim of this investigation is to assess the applicability of this type of observations for the routine implementation of the method. According to the results extracted from the analysis presented here, about half of COSMIC IRO EDP observed under solar minimum (2007-2008) conditions gave neutral gas density with an inaccuracy close to the declared absolute inaccuracy ±(10-15)% of CHAMP observations, with the results being better than the empirical models JB-2008 and MSISE-00 provide. For the other half of IRO EDP, either the solution provided by the method had to be rejected due to insufficient accuracy or no solution could be obtained. For these cases, the parameters foF2 and hmF2 extracted from the corresponding IRO profiles have been found to be inconsistent with the classic mid-latitude daytime F2-layer formalism that the method relies on, and they are incompatible with the general trend provided by the IRI model. For solar maximum conditions (2002) the method was tested with IRO EDP from CHAMP and it is indicated that its performance is quite stable in the sense that a solution could be obtained for all the cases analyzed here. However available CHAMP EDP are confined by ~ 400 km in altitude and this might be the reason for the 20% bias of the retrieved densities toward larger values in respect to the observed densities. IRO observations up to 600 km under solar maximum are required to confirm the exact performance of the method.

Effect of the improved accelerometer calibration method on AIUB's GRACE monthly gravity field solution

NASA Astrophysics Data System (ADS)

Jean, Yoomin; Meyer, Ulrich; Arnold, Daniel; Bentel, Katrin; Jäggi, Adrian

2017-04-01

The monthly global gravity field solutions derived using the measurements from the GRACE (Gravity Recovery and Climate Experiment) satellites have been continuously improved by the processing centers. One of the improvements in the processing method is a more detailed calibration of the on-board accelerometers in the GRACE satellites. The accelerometer data calibration is usually restricted to the scale factors and biases. It has been assumed that the three different axes are perfectly orthogonal in the GRACE science reference frame. Recently, it was shown by Klinger and Mayer-Gürr (2016) that a fully-populated scale matrix considering the non-orthogonality of the axes and the misalignment of the GRACE science reference frame and the GRACE accelerometer frame improves the quality of the C20 coefficient in the GRACE monthly gravity field solutions. We investigate the effect of the more detailed calibration of the GRACE accelerometer data on the C20 coefficient in the case of the AIUB (Astronomical Institute of the University of Bern) processing method using the Celestial Mechanics Approach. We also investigate the effect of the new calibration parameters on the stochastic parameters in the Celestial Mechanics Approach.

LAGEOS-type satellites in critical supplementary orbit configuration and the Lense-Thirring effect detection

NASA Astrophysics Data System (ADS)

Iorio, Lorenzo; Lucchesi, David

2003-07-01

In this paper we analyse quantitatively the concept of LAGEOS-type satellites in critical supplementary orbit configuration (CSOC) which has proved capable of yielding various observables for many tests of general relativity in the terrestrial gravitational field, with particular emphasis on the measurement of the Lense-Thirring effect. By using an entirely new pair of LAGEOS-type satellites in identical, supplementary orbits with, e.g., semimajor axes a = 12 000 km, eccentricity e = 0.05 and inclinations iS1 = 63.4° and iS2 = 116.6°, it would be possible to cancel out the impact of the mismodelling of the static part of the gravitational field of the Earth to a very high level of accuracy. The departures from the ideal supplementary orbital configuration due to the orbital injection errors would yield systematic gravitational errors of the order of a few per cent, according to the covariance matrix of the EGM96 gravity model up to degree l = 20. However, the forthcoming, new gravity models from the CHAMP and GRACE missions should greatly improve the situation. So, it should be possible to measure the gravitomagnetic shifts of the sum of their nodes Σ\\dotΩLT with an accuracy level perhaps less than 1%, of the difference of their perigees Δ\\dotωLT with an accuracy level of 5% and of ≡ Σ\\dotΩLT - Δ\\dotωLT with an accuracy level of 2.8%. Such results, which are due to the non-gravitational perturbations mismodelling, have been obtained for an observational time span of about 6 years and could be further improved by fitting and removing from the analysed time series the major time-varying perturbations which have known periodicities.

Global ionospheric and thermospheric response to the 5 April 2010 geomagnetic storm: An integrated data-model investigation

NASA Astrophysics Data System (ADS)

Lu, G.; Hagan, M. E.; Häusler, K.; Doornbos, E.; Bruinsma, S.; Anderson, B. J.; Korth, H.

2014-12-01

We present a case study of the 5 April 2010 geomagnetic storm using observations and numerical simulations. The event was driven by a fast-moving coronal mass ejection and despite being a moderate storm with a minimum Dst near -50 nT, the event exhibited elevated thermospheric density and surges of traveling atmospheric disturbances (TADs) more typically seen during major storms. The Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIMEGCM) was used to assess how these features were generated and developed during the storm. The model simulations gave rise to TADs that were highly nonuniform with strong latitude and longitude/local time dependence. The TAD phase speeds ranged from 640 m/s to 780 m/s at 400 km and were ~5% lower at 300 km and approximately 10-15% lower at 200 km. In the lower thermosphere around 100 km, the TAD signatures were nearly unrecognizable due to much stronger influence of upward propagating atmospheric tides. The thermosphere simulation results were compared to observations available from the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE), CHAllenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) satellites. Comparison with GOCE data shows that the TIMEGCM reproduced the cross-track winds over the polar region very well. The model-data comparison also revealed some differences, specifically, the simulations underestimated neutral mass density in the upper thermosphere above ~300 km and overestimated the storm recovery tome by 6 h. These discrepancies indicate that some heating or circulation dynamics and potentially cooling processes are not fully represented in the simulations, and also that updates to some parameterization schemes in the TIMEGCM are warranted.

Utilization of lightflecks by seedlings of five dominant tree species of different subtropical forest successional stages under low-light growth conditions.

PubMed

Zhang, Q; Chen, Y J; Song, L Y; Liu, N; Sun, L L; Peng, C L

2012-05-01

We selected five typical tree species, including one early-successional species (ES) Pinus massoniana Lamb., two mid-successional species (MS) Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils. and two late-successional species (LS) Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry., which represent the plants at three successional periods in Dinghushan subtropical forest succession of southern China. Potted seedlings of the five species were grown under 12% of full sunlight for 36 months. The ES and MS showed the slowest and fastest responses to lightflecks, respectively, which correlated with the rate of stomatal opening. In contrast to P. massoniana and C. concinna, the other three species exhibited a high induction loss. Early-successional species showed the lowest specific leaf area and chlorophyll content, the highest photosynthetic capacity (A(max)) and respiratory carbon losses (R(d)). Compared with ES and MS, LS showed lower A(max) and R(d). The five tree species showed a similar chlorophyll a/b ratio after long-term low-light adaptations. On the other hand, LS had a relatively higher de-epoxidation state to protect themselves from excess light during lightflecks. Our results indicated that (i) slower responses to lightflecks could partially explain why ES species could not achieve seedling regeneration in low-light conditions; (ii) fast responses to lightflecks could partially explain why MS species could achieve seedling regeneration in low-light conditions; and (iii) smaller respiratory carbon losses might confer on the LS species a competitive advantage in low-light conditions.

Combination of monthly gravity field solutions from different processing centers

NASA Astrophysics Data System (ADS)

Jean, Yoomin; Meyer, Ulrich; Jäggi, Adrian

2015-04-01

Currently, the official GRACE Science Data System (SDS) monthly gravity field solutions are generated independently by the Centre for Space Research (CSR) and the German Research Centre for Geosciences (GFZ). Additional GRACE SDS monthly fields are provided by the Jet Propulsion Laboratory (JPL) for validation and outside the SDS by a number of other institutions worldwide. Although the adopted background models and processing standards have been harmonized more and more by the various processing centers during the past years, notable differences still exist and the users are more or less left alone with a decision which model to choose for their individual applications. Combinations are well-established in the area of other space geodetic techniques, such as the Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR), and Very Long Baseline Interferometry (VLBI), where regular comparisons and combinations of space-geodetic products have tremendously increased the usefulness of the products in a wide range of disciplines and scientific applications. In the frame of the recently started Horizon 2020 project European Gravity Service for Improved Emergency Management (EGSIEM), a scientific combination service shall therefore be established to deliver the best gravity products for applications in Earth and environmental science research based on the unified knowledge of the European GRACE community. In a first step the large variety of available monthly GRACE gravity field solutions shall be mutually compared spatially and spectrally. We assess the noise of the raw as well as filtered solutions and compare the secular and seasonal periodic variations fitted to the monthly solutions. In a second step we will explore ways to generate combined solutions, e.g., based on a weighted average of the individual solutions using empirical weights derived from pair-wise comparisons. We will also assess the quality of such a combined solution and discuss the potential benefits for the GRACE and GRACE-FO user community.

Gravity Recovery and Interior Laboratory (GRAIL): Extended Mission and End-Game Status

NASA Technical Reports Server (NTRS)

Zuber, Maria T.; Smith, David E.; Wieczorek, Mark A.; Williams, James G.; Andrews-Hanna, Jeffrey C.; Head, James W.; Kiefer, Walter S.; Matsuyama, Isamu; McGovern, Patrick J.; Nimmo, Francis;

Un test de la variation en dents de scie du champ magnétique terrestre par les anomalies du champ magnétique sur les dorsales

NASA Astrophysics Data System (ADS)

Westphal, Michel; Munschy, Marc

1999-10-01

In order to test the possible saw-tooth behaviour of the Earth's magnetic field during stable polarity intervals, we selected several magnetic profiles over the East Indian Ridge, the Juan de Fuca Ridge and the East Pacific Rise. We then compared the stacked magnetic anomaly profiles with different models. It appears that neither the uniform pattern nor the saw-tooth pattern fully explain the shape of all anomalies. We propose a new magnetic field model with a gradual transition between Gauss and Matuyama periods and smaller intensities for some short episodes.

Development of the Los Alamos continuous high average-power microsecond pulser ion accelerator

NASA Astrophysics Data System (ADS)

Bitteker, L. J.; Wood, B. P.; Davis, H. A.; Waganaar, W. J.; Boyd, I. D.; Lovberg, R. H.

2000-10-01

The continuous high average-power microsecond pulser (CHAMP) ion accelerator is being constructed at Los Alamos National Laboratory. Progress on the testing of the CHAMP diode is discussed. A direct simulation Monte Carlo computer code is used to investigate the puffed gas fill of the CHAMP anode. High plenum pressures and low plenum volumes are found to be desirable for effective gas puffs. The typical gas fill time is 150-180 μs from initiation of valve operation to end of fill. Results of anode plasma production at three stages of development are discussed. Plasma properties are monitored with electric and magnetic field probes. From this data, the near coil plasma density under nominal conditions is found to be on the order of 1×1016 cm-3. Large error is associated with this calculation due to inconsistencies between tests and the limitations of the instrumentation used. The diode insulating magnetic field is observed to result in lower density plasma with a more diffuse structure than for the cases when the insulating field is not applied. The importance of these differences in plasma quality on the beam production is yet to be determined.

Reliability of Physical Activity Measures During Free-Living Activities in People After Total Knee Arthroplasty.

PubMed

Almeida, Gustavo J; Irrgang, James J; Fitzgerald, G Kelley; Jakicic, John M; Piva, Sara R

2016-06-01

Few instruments that measure physical activity (PA) can accurately quantify PA performed at light and moderate intensities, which is particularly relevant in older adults. The evidence of their reliability in free-living conditions is limited. The study objectives were: (1) to determine the test-retest reliability of the Actigraph (ACT), SenseWear Armband (SWA), and Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire in assessing free-living PA at light and moderate intensities in people after total knee arthroplasty; (2) to compare the reliability of the 3 instruments relative to each other; and (3) to determine the reliability of commonly used monitoring time frames (24 hours, waking hours, and 10 hours from awakening). A one-group, repeated-measures design was used. Participants wore the activity monitors for 2 weeks, and the CHAMPS questionnaire was completed at the end of each week. Test-retest reliability was determined by using the intraclass correlation coefficient (ICC [2,k]) to compare PA measures from one week with those from the other week. Data from 28 participants who reported similar PA during the 2 weeks were included in the analysis. The mean age of these participants was 69 years (SD=8), and 75% of them were women. Reliability ranged from moderate to excellent for the ACT (ICC=.75-.86) and was excellent for the SWA (ICC=.93-.95) and the CHAMPS questionnaire (ICC=.86-.92). The 95% confidence intervals (95% CI) of the ICCs from the SWA were the only ones within the excellent reliability range (.85-.98). The CHAMPS questionnaire showed systematic bias, with less PA being reported in week 2. The reliability of PA measures in the waking-hour time frame was comparable to that in the 24-hour time frame and reflected most PA performed during this period. Reliability may be lower for time intervals longer than 1 week. All PA measures showed good reliability. The reliability of the ACT was lower than those of the SWA and the CHAMPS questionnaire. The SWA provided more precise reliability estimates. Wearing PA monitors during waking hours provided sufficiently reliable measures and can reduce the burden on people wearing them. © 2016 American Physical Therapy Association.

Nouvelles approches en theorie du champ moyen dynamique: le cas du pouvoir thermoelectrique et celui de l'effet orbital d'un champ magnetique

NASA Astrophysics Data System (ADS)

Arsenault, Louis-Francois

Les applications reliees a la generation d'energie motivent la recherche de materiaux ayant un fort pouvoir thermoelectrique (S). De plus, S nous renseigne sur certaines proprietes fondamentales des materiaux, comme, par exemple, la transition entre l'etat coherent et incoherent des quasi-particules lorsque la temperature augmente. Empiriquement, la presence de fortes interactions electron-electron peut mener a un pouvoir thermoelectrique geant. Nous avons donc etudie le modele le plus simple qui tient compte de ces fortes interactions, le modele de Hubbard. La theorie du champ moyen dynamique (DMFT) est tout indiquee dans ce cas. Nous nous sommes concentres sur un systeme tridimensionnel (3d) cubique a face centree (fcc), et ce, pour plusieurs raisons. A) Ce type de cristal est tres commun dans la nature. B) La DMFT donne de tres bons resultats en 3d et donc ce choix sert aussi de preuve de principe de la methode. C) Finalement, a cause de la frustration electronique intrinseque au fcc, celui-ci ne presente pas de symetrie particule-trou, ce qui est tres favorable a l'apparition d'une grande valeur de S. Ce travail demontre que lorsque le materiau est un isolant a demi-remplissage a cause des fortes interactions (isolant de Mott), il est possible d'obtenir de grands pouvoirs thermoelectriques en le dopant legerement. C'est un resultat pratique important. Du point de vue methodologique, nous avons montre comment la limite de frequence infinie de S et l'approche dite de Kelvin, qui considere la limite de frequence nulle avant la limite thermodynamique pour S, donnent des estimations fiables de la vraie limite continue (DC) dans les domaines de temperature appropriee. Ces deux approches facilitent grandement les calculs en court-circuit ant la necessite de recourir a de problematiques prolongements analytiques. Nous avons trouve que la methode de calcul a frequence infinie fonctionne bien lorsque les echelles d'energie sont relativement faibles. En d'autres termes, cette approche donne une bonne representation de S lorsque le systeme devient coherent. Les calculs montrent aussi que la formule Kelvin est precise lorsque la fonction spectrale des electrons devient incoherente, soit a plus haute temperature. Dans la limite Kelvin, S est essentiellement l'entropie par particule, tel que propose il y a longtemps. Nos resultats demontrent ainsi que la vision purement entropique de S est la bonne dans le regime incoherent, alors que dans le regime coherent, l'approche a frequence infinie est meilleure. Nous avons utilise une methode a la fine pointe, soit le Monte-Carlo quantique en temps continu pour resoudre la DMFT. Pour permettre une exploration rapide du diagramme de phase, nous avons du developper une nouvelle version de la methode des perturbations iterees pour qu'elle soit applicable aussi a forte interaction au-dela de la valeur critique de la transition de Mott. Un autre sujet a aussi ete aborde. L'effet orbital du champ magnetique dans les systemes electroniques fortement correles est une question tres importante et peu developpee. Cela est d'autant plus essentiel depuis la decouverte des oscillations quantiques dans les supraconducteurs a haute temperature (haut- Tc). Par desir de developper une methode la moins biaisee possible, nous avons derive la DMFT lorsqu'un champ se couplant a l'operateur energie cinetique par la substitution de Peierls est present. Ce type d'approche est necessaire pour comprendre entre autres l'effet de la physique de Mott sur des phenomenes tels que les oscillations quantiques. Nous avons obtenu un resultat tres important en demontrant rigoureusement que la relation d'auto-coherence de la DMFT et le systeme intermediaire d'impurete quantique restent les memes. L'effet du champ peut etre contenu dans la fonction de Green locale, ce qui constitue la grande difference avec le cas habituel. Ceci permet de continuer a utiliser les solutionneurs d'impuretes standards, qui sont de plus en plus puissants. Nous avons aussi developpe la methode pour le cas d'un empilement de plans bidimensionnels selon z, ce qui permet d'etudier l'effet orbital du champ dans des nanostructures et meme dans les materiaux massifs, si le nombre de plans est suffisant pour obtenir la limite tridimensionnelle. Mots cles : Pouvoir thermoelectrique, Theorie du Champ Moyen Dynamique, Modele de Hubbard, Effet orbital du champ magnetique, Electrons fortement correles, Materiaux quantiques, Theorie des perturbations iterees

Regularized GRACE monthly solutions by constraining the difference between the longitudinal and latitudinal gravity variations

NASA Astrophysics Data System (ADS)

Chen, Qiujie; Chen, Wu; Shen, Yunzhong; Zhang, Xingfu; Hsu, Houze

2016-04-01

The existing unconstrained Gravity Recovery and Climate Experiment (GRACE) monthly solutions i.e. CSR RL05 from Center for Space Research (CSR), GFZ RL05a from GeoForschungsZentrum (GFZ), JPL RL05 from Jet Propulsion Laboratory (JPL), DMT-1 from Delft Institute of Earth Observation and Space Systems (DEOS), AIUB from Bern University, and Tongji-GRACE01 as well as Tongji-GRACE02 from Tongji University, are dominated by correlated noise (such as north-south stripe errors) in high degree coefficients. To suppress the correlated noise of the unconstrained GRACE solutions, one typical option is to use post-processing filters such as decorrelation filtering and Gaussian smoothing , which are quite effective to reduce the noise and convenient to be implemented. Unlike these post-processing methods, the CNES/GRGS monthly GRACE solutions from Centre National d'Etudes Spatiales (CNES) were developed by using regularization with Kaula rule, whose correlated noise are reduced to such a great extent that no decorrelation filtering is required. Actually, the previous studies demonstrated that the north-south stripes in the GRACE solutions are due to the poor sensitivity of gravity variation in east-west direction. In other words, the longitudinal sampling of GRACE mission is very sparse but the latitudinal sampling of GRACE mission is quite dense, indicating that the recoverability of the longitudinal gravity variation is poor or unstable, leading to the ill-conditioned monthly GRACE solutions. To stabilize the monthly solutions, we constructed the regularization matrices by minimizing the difference between the longitudinal and latitudinal gravity variations and applied them to derive a time series of regularized GRACE monthly solutions named RegTongji RL01 for the period Jan. 2003 to Aug. 2011 in this paper. The signal powers and noise level of RegTongji RL01 were analyzed in this paper, which shows that: (1) No smoothing or decorrelation filtering is required for RegTongji RL01 anymore. (2) The signal powers of RegTongji RL01 are obviously stronger than those of the filtered solutions but the noise levels of the regularized and filtered solutions are consistent, suggesting that RegTongji RL01 has the higher signal-to-noise ratio.

Ground Based Investigation of Electrostatic Accelerometer in HUST

NASA Astrophysics Data System (ADS)

Bai, Y.; Zhou, Z.

2013-12-01

High-precision electrostatic accelerometers with six degrees of freedom (DOF) acceleration measurement were successfully used in CHAMP, GRACE and GOCE missions which to measure the Earth's gravity field. In our group, space inertial sensor based on the capacitance transducer and electrostatic control technique has been investigated for test of equivalence principle (TEPO), searching non-Newtonian force in micrometer range, and satellite Earth's field recovery. The significant techniques of capacitive position sensor with the noise level at 2×10-7pF/Hz1/2 and the μV/Hz1/2 level electrostatic actuator are carried out and all the six servo loop controls by using a discrete PID algorithm are realized in a FPGA device. For testing on ground, in order to compensate one g earth's gravity, the fiber torsion pendulum facility is adopt to measure the parameters of the electrostatic controlled inertial sensor such as the resolution, and the electrostatic stiffness, the cross couple between different DOFs. A short distance and a simple double capsule equipment the valid duration about 0.5 second is set up in our lab for the free fall tests of the engineering model which can directly verify the function of six DOF control. Meanwhile, high voltage suspension method is also realized and preliminary results show that the horizontal axis of acceleration noise is about 10-8m/s2/Hz1/2 level which limited mainly by the seismic noise. Reference: [1] Fen Gao, Ze-Bing Zhou, Jun Luo, Feasibility for Testing the Equivalence Principle with Optical Readout in Space, Chin. Phys. Lett. 28(8) (2011) 080401. [2] Z. Zhu, Z. B. Zhou, L. Cai, Y. Z. Bai, J. Luo, Electrostatic gravity gradiometer design for the advanced GOCE mission, Adv. Sp. Res. 51 (2013) 2269-2276. [3] Z B Zhou, L Liu, H B Tu, Y Z Bai, J Luo, Seismic noise limit for ground-based performance measurements of an inertial sensor using a torsion balance, Class. Quantum Grav. 27 (2010) 175012. [4] H B Tu, Y Z Bai, Z B Zhou, L Liu, L Cai, and J Luo, Performance measurements of an inertial sensor with a two-stage controlled torsion pendulum, Class Quantum. Grav. 27 (2010) 205016.

Satellite observations of middle atmosphere-thermosphere vertical coupling by gravity waves

NASA Astrophysics Data System (ADS)

Trinh, Quang Thai; Ern, Manfred; Doornbos, Eelco; Preusse, Peter; Riese, Martin

2018-03-01

Atmospheric gravity waves (GWs) are essential for the dynamics of the middle atmosphere. Recent studies have shown that these waves are also important for the thermosphere/ionosphere (T/I) system. Via vertical coupling, GWs can significantly influence the mean state of the T/I system. However, the penetration of GWs into the T/I system is not fully understood in modeling as well as observations. In the current study, we analyze the correlation between GW momentum fluxes observed in the middle atmosphere (30-90 km) and GW-induced perturbations in the T/I. In the middle atmosphere, GW momentum fluxes are derived from temperature observations of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite instrument. In the T/I, GW-induced perturbations are derived from neutral density measured by instruments on the Gravity field and Ocean Circulation Explorer (GOCE) and CHAllenging Minisatellite Payload (CHAMP) satellites. We find generally positive correlations between horizontal distributions at low altitudes (i.e., below 90 km) and horizontal distributions of GW-induced density fluctuations in the T/I (at 200 km and above). Two coupling mechanisms are likely responsible for these positive correlations: (1) fast GWs generated in the troposphere and lower stratosphere can propagate directly to the T/I and (2) primary GWs with their origins in the lower atmosphere dissipate while propagating upwards and generate secondary GWs, which then penetrate up to the T/I and maintain the spatial patterns of GW distributions in the lower atmosphere. The mountain-wave related hotspot over the Andes and Antarctic Peninsula is found clearly in observations of all instruments used in our analysis. Latitude-longitude variations in the summer midlatitudes are also found in observations of all instruments. These variations and strong positive correlations in the summer midlatitudes suggest that GWs with origins related to convection also propagate up to the T/I. Different processes which likely influence the vertical coupling are GW dissipation, possible generation of secondary GWs, and horizontal propagation of GWs. Limitations of the observations as well as of our research approach are discussed.

Requirement for specific gravity and creatinine adjustments for urinary steroids and luteinizing hormone concentrations in adolescents.

PubMed

Singh, Gurmeet K S; Balzer, Ben W R; Desai, Reena; Jimenez, Mark; Steinbeck, Katharine S; Handelsman, David J

2015-11-01

Urinary hormone concentrations are often adjusted to correct for hydration status. We aimed to determine whether first morning void urine hormones in growing adolescents require adjustments and, if so, whether urinary creatinine or specific gravity are better adjustments. The study population was adolescents aged 10.1 to 14.3 years initially who provided fasting morning blood samples at 0 and 12 months (n = 343) and first morning urine every three months (n = 644). Unadjusted, creatinine and specific gravity-adjusted hormonal concentrations were compared by Deming regression and Bland-Altman analysis and grouped according to self-rated Tanner stage or chronological age. F-ratios for self-rated Tanner stages and age groups were used to compare unadjusted and adjusted hormonal changes in growing young adolescents. Correlations of paired serum and urinary hormonal concentration of unadjusted and creatinine and specific gravity-adjusted were also compared. Fasting first morning void hormone concentrations correlated well and were unbiased between unadjusted or adjusted by either creatinine or specific gravity. Urine creatinine concentration increases with Tanner stages, age and male gender whereas urine specific gravity was not influenced by Tanner stage, age or gender. Adjustment by creatinine or specific gravity of urinary luteinizing hormone, estradiol, testosterone, dihydrotestosterone and dehydroepiandrosterone concentrations did not improve correlation with paired serum concentrations. Urine steroid and luteinizing hormone concentrations in first morning void samples of adolescents are not significantly influenced by hydration status and may not require adjustments; however, if desired, both creatinine and specific gravity adjustments are equally suitable. © The Author(s) 2015.

Low-degree gravity change from GPS data of COSMIC and GRACE satellite missions

NASA Astrophysics Data System (ADS)

Lin, Tingjung; Hwang, Cheinway; Tseng, Tzu-Pang; Chao, B. F.

2012-01-01

This paper demonstrates estimation of time-varying gravity harmonic coefficients from GPS data of COSMIC and GRACE satellite missions. The kinematic orbits of COSMIC and GRACE are determined to the cm-level accuracy. The NASA Goddard's GEODYN II software is used to model the orbit dynamics of COSMIC and GRACE, including the effect of a static gravity field. The surface forces are estimated per one orbital period. Residual orbits generated from kinematic and reference orbits serve as observables to determine the harmonic coefficients in the weighted-constraint least-squares. The monthly COSMIC and GRACE GPS data from September 2006 to December 2007 (16 months) are processed to estimate harmonic coefficients to degree 5. The geoid variations from the GPS and CSR RL04 (GRACE) solutions show consistent patterns over space and time, especially in regions of active hydrological changes. The monthly GPS-derived second zonal coefficient closely resembles the SLR-derived and CSR RL04 values, and third and fourth zonal coefficients resemble the CSR RL04 values.

Neuro-vestibular and Sensory-motor Challenges Associated with NASA Mission Architectures for Moon and Mars

NASA Technical Reports Server (NTRS)

Paloski, William H.

2004-01-01

Data from six-month low Earth orbit space flight missions suggest that that substantial neuro-vestibular/sensory-motor adaptation will take place during six-month transit missions to and from Mars. Could intermittent or continuous artificial gravity be used to offset these effects? To what degree would the effects of adaptation to this rotational cure affect its potential benefits? Also, little information exists regarding the gravity thresholds for maintaining functional performance of complex sensory-motor tasks such as balance control and locomotion. Will sensory-motor coordination systems adapt to 30- 90 days of 1/6 g on the lunar surface or 18 months of 3/8 g on the Martian surface? Would some form of gravity replacement therapy be required on the surface? And, will transitions between 0 g and 1/6 g or 1/3 g present as great a challenge to the vestibular system as transitions between 0 g and 1 g? Concerted research and development efforts will be required to obtain the answers.

Neuro-vestibular and Sensory-motor Challenges Associated with NASA Mission Architectures for Moon and Mars

NASA Technical Reports Server (NTRS)

Paloski, William H.

2004-01-01

Data from six-month low Earth orbit space flight missions suggest that that substantial neuro-vestibuladsensory-motor adaptation will take place during six-month transit missions to and from Mars. Could intermittent or continuous artificial gravity be used to offset these effects? To what degree would the effects of adaptation to this rotational cure affect its potential benefits? Also, little information exists regarding the gravity thresholds for maintaining functional performance of complex sensory-motor tasks such as balance control and locomotion. Will sensory-motor coordination systems adapt to 30-90 days of 1/6 g on the lunar surface or 18 months of 3/8 g on the Martian surface? Would some form of gravity replacement therapy be required on the surface? And, will transitions between 0 g and 1/6 g or 1/3 g present as great a challenge to the vestibular system as transitions between 0 g and 1 g? Concerted research and development efforts will be required to obtain the answers.

KENNEDY SPACE CENTER, FLA. - This logo for the Gravity Probe B mission portrays the theory of curved spacetime and "frame-dragging," developed by Einstein and other scientists, that the mission will test. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit. Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring the effects. The experiment was developed by Stanford University, NASA’s Marshall Space Flight Center and Lockheed Martin.

NASA Image and Video Library

2003-10-30

KENNEDY SPACE CENTER, FLA. - This logo for the Gravity Probe B mission portrays the theory of curved spacetime and "frame-dragging," developed by Einstein and other scientists, that the mission will test. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit. Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring the effects. The experiment was developed by Stanford University, NASA’s Marshall Space Flight Center and Lockheed Martin.

Satellite gravity field derivatives for identifying geological boundaries.

NASA Astrophysics Data System (ADS)

Alvarez, O.; Gimenez, M.; Braitenberg, C.; Folguera, A.

2012-04-01

The Pampean flat slab zone developed in the last 17 Ma between 27° and 33°S, and has denuded an intricate collage of crustal blocks amalgamated during the Pampean, Famatinian and San Rafael deformational stages, that is far of being completely understood. For potential field studies these amalgamations have the effect of defining important compositional and density heterogeneities. Geophysical data from different studies show a sharp boundary between the two adjacent and contrasting crusts of Pampia and the Cuyania terrane. Recent aeromagnetic surveys have inferred a mafic and ultramafic belt interpreted as a buried ophiolitic suite hosted in the corresponding suture. This boundary coincides locally with basement exposures of high to medium grade metamorphic rocks developed in close association with the Famatinian orogen of Early to Middle Ordovician age. Lower crustal rocks are exposed along this first order crustal discontinuity. The Río de la Plata basement crops out from southern Uruguay to eastern-center Argentina with an approximate surface of 20,000 km2. Oldest rocks have been dated in 2,200 and 1,700 Ma, indicating that they constituted a different block to Pampia. The boundary between Pampia and the Rio de la Plata craton is not exposed. However, a strong gravimetric anomaly identified in the central part of the foothills of the Sierras de Córdoba indicates a first order crustal discontinuity that has been related to their collision in Neoproterozoic times. This work focuses on the determination of mass heterogeneities over the Pampean flat slab zone using gravity anomaly and vertical gravity gradient, with the aim to determine discontinuities in the pattern of terrain amalgamation that conformed the basement. Satellite gravimetry is highly sensitive to these variations. Recent satellite missions, (CHAMP, GRACE, and GOCE) have introduced an extraordinary improvement in the global mapping of the gravity field. We control the quality of the terrestrial data entering the EGM2008 by a comparison analysis with the satellite only gravitational model of GOCE up to degree N=250. Using the global model EGM2008, the vertical gravity gradient and the gravity anomaly for South Central Andes are calculated. We correct the observations for the topographic effect using tesseroids by using a 1-arc minute global relief model of earth's surface. Results are compared to a schematic geological map of the South Central Andes region, which includes main geological features with regional dimensions presumably accompanied by crustal density variations. We clearly depict the geological structures and delineation of significant terrains such as Pampia, Cuyania, and Chilenia terranes. Of great interest is the contact between the Rio de la Plata craton and the Pampia Terrain, a boundary that has not been clearly defined till now. Our work aims to highlight the potential of this new tool of satellite gravimetry, with the addition of topographic correction, to achieve tectonic interpretation of medium to long wavelength of a determined study region. We demonstrate that the new gravity fields can be used for identifying geological boundaries related to density differences, in a regional dimension and thus are a new useful tool in geophysical exploration.

ARISTOTELES: A European approach for an Earth gravity field recovery mission

NASA Technical Reports Server (NTRS)

Benz, R.; Faulks, H.; Langemann, M.

1989-01-01

Under contract of the European Space Agency a system study for a spaceborne gravity field recovery mission was performed, covering as a secondary mission objective geodetic point positioning in the cm range as well. It was demonstrated that under the given programmatic constraints including dual launch and a very tight development schedule, a six months gravity field mission in a 200 km near polar, dawn-dusk orbit is adequate to determine gravity anomalies to better than 5 mgal with a spatial resolution of 100 x 100 km half wavelength. This will enable scientists to determine improved spherical harmonic coefficients of the Earth gravity field equation to the order and degree of 180 or better.

Accounting for time- and space-varying changes in the gravity field to improve the network adjustment of relative-gravity data

USGS Publications Warehouse

Kennedy, Jeffrey R.; Ferre, Ty P.A.

2015-01-01

The relative gravimeter is the primary terrestrial instrument for measuring spatially and temporally varying gravitational fields. The background noise of the instrument—that is, non-linear drift and random tares—typically requires some form of least-squares network adjustment to integrate data collected during a campaign that may take several days to weeks. Here, we present an approach to remove the change in the observed relative-gravity differences caused by hydrologic or other transient processes during a single campaign, so that the adjusted gravity values can be referenced to a single epoch. The conceptual approach is an example of coupled hydrogeophysical inversion, by which a hydrologic model is used to inform and constrain the geophysical forward model. The hydrologic model simulates the spatial variation of the rate of change of gravity as either a linear function of distance from an infiltration source, or using a 3-D numerical groundwater model. The linear function can be included in and solved for as part of the network adjustment. Alternatively, the groundwater model is used to predict the change of gravity at each station through time, from which the accumulated gravity change is calculated and removed from the data prior to the network adjustment. Data from a field experiment conducted at an artificial-recharge facility are used to verify our approach. Maximum gravity change due to hydrology (observed using a superconducting gravimeter) during the relative-gravity field campaigns was up to 2.6 μGal d−1, each campaign was between 4 and 6 d and one month elapsed between campaigns. The maximum absolute difference in the estimated gravity change between two campaigns, two months apart, using the standard network adjustment method and the new approach, was 5.5 μGal. The maximum gravity change between the same two campaigns was 148 μGal, and spatial variation in gravity change revealed zones of preferential infiltration and areas of relatively high groundwater storage. The accommodation for spatially varying gravity change would be most important for long-duration campaigns, campaigns with very rapid changes in gravity and (or) campaigns where especially precise observed relative-gravity differences are used in the network adjustment.

Satellite observations of ground water changes in New Mexico

USDA-ARS?s Scientific Manuscript database

In 2002 NASA launched the Gravity Recovery and Climate Experiment (GRACE) satellite mission. GRACE consists of two satellites with a separation of about 200 km.  By accurately measuring the separation between the twin satellites, the differences in the gravity field can be determined. Monthly observ...

Development of Gravity-Sensing Organs in Altered Gravity

NASA Technical Reports Server (NTRS)

Wiederhold, M. L.; Gao, W. Y.; Harrison, J. L.; Hejl, R.

1996-01-01

Experiments are described in which the development of the gravity-sensing organs was studied in newt larvae reared in micro-g on the IML-2 mission and in Aplysia embryos and larvae reared on a centrifuge at 1 to 5 g. In Aplysia embryos, the statolith (single dense mass on which gravity and linear acceleration act) was reduced in size in a graded fashion at increasing g. In early post-metamorphic Aplysia or even in isolated statocysts from such animals, the number of statoconia produced is reduced at high gravity Newt larvae launched before any of the otoconia were formed and reared for 15 days in micro-gravity had nearly adult labyrinths at the end of the IML-2 mission. The otoliths of the saccule and utricle were the same size in flight and ground-reared larvae. However, the system of aragonitic otoconia produced in the endolymphatic sac in amphibians was much larger and developed earlier in the flight-reared larvae. At later developmental stages, the aragonitic otoconia enter and fill the saccule. One flight-reared larva was maintained for nine months post-flight and the size of the saccular otolith, as well as the volume of otoconia within the endolymphatic sac, were considerably larger than in age-matched, ground-reared newts. This suggests that rearing in micro-gravity initiates a process that continues for several months after introduction to 1-g, which greatly increases the volume of otoconia. The flight-reared animal had abnormal posture, pointing its head upward, whereas normal ground-reared newts always keep their head horizontal. This suggests that rearing for even a short period in micro-gravity can have lasting functional consequences in an animal subsequently reared in 1-g conditions on Earth.

Geomagnetic main field modeling with DMSP

NASA Astrophysics Data System (ADS)

Alken, P.; Maus, S.; Lühr, H.; Redmon, R. J.; Rich, F.; Bowman, B.; O'Malley, S. M.

2014-05-01

The Defense Meteorological Satellite Program (DMSP) launches and maintains a network of satellites to monitor the meteorological, oceanographic, and solar-terrestrial physics environments. In the past decade, geomagnetic field modelers have focused much attention on magnetic measurements from missions such as CHAMP, Ørsted, and SAC-C. With the completion of the CHAMP mission in 2010, there has been a multiyear gap in satellite-based vector magnetic field measurements available for main field modeling. In this study, we calibrate the special sensor magnetometer instrument on board DMSP to create a data set suitable for main field modeling. These vector field measurements are calibrated to compute instrument timing shifts, scale factors, offsets, and nonorthogonality angles of the fluxgate magnetometer cores. Euler angles are then computed to determine the orientation of the vector magnetometer with respect to a local coordinate system. We fit a degree 15 main field model to the data set and compare with the World Magnetic Model and Ørsted scalar measurements. We call this model DMSP-MAG-1, and its coefficients and software are available for download at http://geomag.org/models/dmsp.html. Our results indicate that the DMSP data set will be a valuable source for main field modeling for the years between CHAMP and the recently launched Swarm mission.

Transverse magnetic field effects on the resonant tunneling current

NASA Astrophysics Data System (ADS)

Cury, L. A.; Celeste, A.; Goutiers, B.; Portal, J. C.; Sivco, D. L.; Cho, A. Y.

1991-04-01

Resonant tunneling process in an (InGa)As-(InAI)As symmetric double-barrier structure subjected to a transverse magnetic field B_{perp} (perpendicular to the current) is investigated. We particularly focus on the experimental behaviour of V_p, the voltage at the current peak position, as a function of the magnetic field B_{perp}. For strong magnetic fields a clear dependence on B_{perp}^2 is observed, as expected. However, an original result is obtained at small magnetic fields where a deviation from the parabolic behaviour is observed. The more complicated dependence on B_{perp} of V_p is obtained from a numerical fit. A qualitative discussion is proposed on the basis of a previous publication (L. A. Cury, A. Celeste, J. C. Portal, Solid-States Electron. 32 (1989) 1689) and the differences with the results of other authors are pointed out. Un système à double barrière à semiconducteurs basé sur les alliages (InGa)As(InAI)As est étudié sous un fort champ magnétique transverse B_{perp} (perpendiculaire au courant). On étudie plus particulièrement la variation expérimentale de la tension V_p associée au courant pic en fonction du champ magnétique B_{perp}. A très fort champ, le comportement attendu de V_p en B_{perp}^2 est observé. Dans le domaine des bas champs magnétiques une déviation du comportement quadratique est mise en évidence. Le comportement plus compliqué de V_p en fonction de B_{perp} est obtenu au travers d'un lissage numérique. Nous proposons une discussion qualitative, de ces résultats, fondée sur notre travail antérieur (L. A. Cury, A. Celeste, J. C. Portal, Solid-States Electron. 32 (1989) 1689) ainsi qu'une comparaison avec les résultats d'autres auteurs.

Parental Perspectives of a 4-Week Family-Based Lifestyle Intervention for Children with Obesity

PubMed Central

Pearson, Erin S.; Irwin, Jennifer D.; Burke, Shauna M.; Shapiro, Sheree

2013-01-01

Objectives: The childhood obesity epidemic is now recognized as one of the most serious public health challenges of the 21st century. Community-based behaviour modification treatment programs involving both children and their families are warranted. The purpose of this study was to explore the experiences of parents whose children participated in the Children's Health and Activity Modification Program (C.H.A.M.P.): a 4-week lifestyle program delivered as a day-camp for obese children at risk for type II diabetes and their families. Parents were required to attend four half-day education sessions during the intervention period. Methods: Seven focus groups were conducted immediately following the 4-week interventions offered in August 2008 and 2009. The perspectives of 38 parents representing 32 children aged 8-14 with obesity (i.e., body mass index > the 95th percentile) were shared. Results: Overall, parents were pleased with the impact of the program and proud of their children's accomplishments (e.g., increased physical activity levels, enhanced self-esteem, weight loss). Several facilitators to success (e.g., social support; a positive environment) and barriers to its maintenance (e.g., time management; unsupportive family members) were identified, and recommendations were made for future programs. Although parents found the half-day sessions valuable, post-programmatic bi-monthly booster session adherence declined over the one-year follow-up period. Conclusion: Delivered as a 4-week day-camp, C.H.A.M.P. represents a unique approach to the treatment of childhood obesity. Future family-based interventions should consider avenues for intensifying the parental program component whilst employing strategies to promote parental adherence in service of enhancing long-term sustainability of health behaviour changes. PMID:23445699

Association between pain and the frailty phenotype in older men: longitudinal results from the Concord Health and Ageing in Men Project (CHAMP).

PubMed

Megale, Rodrigo Z; Ferreira, Manuela L; Ferreira, Paulo H; Naganathan, Vasi; Cumming, Robert; Hirani, Vasant; Waite, Louise M; Seibel, Markus J; Le Couteur, David G; Handelsman, David J; Blyth, Fiona M

2018-05-01

to determine whether pain increases the risk of developing the frailty phenotype and whether frailty increases the risk of developing chronic or intrusive pain, using longitudinal data. longitudinal data from the Concord Health and Ageing in Men Project (CHAMP), a prospective population based cohort study. a total of 1,705 men aged 70 years or older, living in an urban area of New South Wales, Australia. data on the presence of chronic pain (daily pain for at least 3 months), intrusive pain (pain causing moderate to severe interference with activities) and the criteria for the Cardiovascular Health Study (CHS) frailty phenotype were collected in three waves, from January 2005 to October 2013. Data on age, living arrangements, education, smoking status, alcohol consumption, body mass index, comorbidities, cognitive function, depressive symptoms and history of vertebral or hip fracture were also collected and included as covariates in the analyses. a total of 1,705 participants were included at baseline, of whom 1,332 provided data at the 2-year follow-up and 940 at the 5-year follow-up. Non-frail (robust and pre-frail) men who reported chronic pain were 1.60 (95% confidence interval (CI): 1.02-2.51, P = 0.039) times more likely to develop frailty at follow-up, compared to those with no pain. Intrusive pain did not significantly increase the risk of future frailty. Likewise, the frailty status was not associated with future chronic or intrusive pain in the adjusted analysis. the presence of chronic pain increases the risk of developing the frailty phenotype in community-dwelling older men.

Le changement comme tradition dans la recherche et la formation a la recherche en biotechnologie et en peripherie Etude de cas en sciences de la sante, sciences naturelles et genie

NASA Astrophysics Data System (ADS)

Bourque, Claude Julie

Le champ de la recherche scientifique et de la formation a la recherche est traverse depuis quelques dizaines d'annees par plusieurs courants et discours associes au changement, mais peu de travaux empiriques permettent de comprendre ce qui change concretement. C'est la contribution originale de cette these au champ de l'education, plus specifiquement a l'etude sociologique de l'enseignement superieur ou sont concentrees les activites liees a la triade thematique du programme doctoral dans lequel elle a ete produite : recherche, formation et pratique. L'enquete-terrain a ete realisee en 2009 et 2010 aupres de 808 repondants affilies a 60 etablissements au Quebec et a produit un vaste materiau de nature mixte (donnees quantitatives et qualitatives). Un portrait de la nebuleuse biotechnologique qui touche les secteurs des sciences de la sante, des sciences naturelles et du genie a ete realise. Ce domaine concerne des dizaines de disciplines et se revele de nature transdisciplinaire, mais les pratiques n'y sont pas davantage marquees par le changement que celles d'autres domaines connexes. Les dynamiques sociales ont fait l'objet d'analyses comparatives dans quatre contextes: le choix des programmes, des objets et des methodes, le financement, la diffusion et la planification de la carriere. Les resultats indiquent que les echanges entre les agents traditionnellement situes au coeur des activites de recherche dominent ces dynamiques dans tous les contextes etudies. L'etude des representations au fondement des pratiques a revele l'existence de trois ecoles de pensee qui coexistent dans le champ scientifique: academique, pragmatique et economiste. Ces ecoles permettent de categoriser les agents en fonction des zones de fractures qui marquent leurs oppositions tout en identifiant ce qu'ils ont en commun. Les representations et les pratiques liees a la formation temoignent d'un habitus plutot homogene, alors que les contradictions semblent plus souvent ancrees dans des luttes universitaires que scientifiques, concentrees sur la negociation du capital scientifique, symbolique et economique en jeu dans la formation doctorale, dans les carrieres auxquelles elle mene, et dans les qualites du titre de Ph.D. Au final, la confusion entre des logiques opposees peut etre reduite en reinterpretant le changement comme tradition du champ scientifique. Mots-cles Sociologie, education, enseignement superieur, science et technologie, biotechnologie, formation doctorale, champ scientifique, reseaux sociaux

Time Periods of Unusual Density Behavior Observed by GRACE and CHAMP

NASA Astrophysics Data System (ADS)

McLaughlin, C. A.; Fattig, E.; Mysore Krishna, D.; Locke, T.; Mehta, P. M.

2011-12-01

Time periods of low cross correlation between precision orbit ephemeris (POE) derived density and accelerometer density for CHAMP and GRACE are examined. In particular, the cross correlation for GRACE dropped from typical values near 0.9 to much lower values and then returned to typical over the time period of late October to late December of 2005. This time period includes a maneuver where GRACE-A and GRACE-B swapped positions. However, the drop in cross correlation begins and reaches its low point before the maneuvers begin. In addition, the densities were found using GRACE-A, but GRACE-B did most of the maneuvering. The time period is characterized by high frequency variations in accelerometer density of the same magnitude as the daylight to eclipse variations over the course of an orbit. However, the daylight to eclipse variations are particularly small during this time period because the orbit plane is near the terminator. Additionally, the difference between the accelerometer and POE derived densities are not unusually large during this time period. This implies the variations are not unusual, just more significant when the orbit plane is near terminator. Cyclical variations in correlation of the POE derived densities with accelerometer derived densities are seen for both GRACE and CHAMP, but the magnitude of the variations are much larger for GRACE, possibly because of the higher altitude of GRACE. The cycles seem to be phased so that low correlations occur with low beta angle when the orbit plane is near the terminator. The low correlation is possibly caused by the lower amplitude of the daylight to eclipse signal making higher frequency variations relatively more important. However, another possible explanation is terminator waves in density that propagate to the thermosphere from lower in the atmosphere. These waves have been observed in CHAMP accelerometer data and global circulation model simulations. Further investigation is needed to see if the variations correspond to terminator waves or if they represent typical high frequency signal from another source that is more apparent when the orbit plane is near the terminator. 1. C. A. McLaughlin, E. Fattig, D. Mysore Krishna, and P. M. Mehta, "Time Periods of Anomalous Density for GRACE and CHAMP," AAS/AIAA Astrodynamics Specialists Conference, AAS 11-613, Girdwood, AK, August 2011. 2. C. A. McLaughlin, A. Hiatt, and T. Lechtenberg, "Calibrating Precision Orbit Derived Total Density," Journal of Spacecraft and Rockets, Vol. 48, No. 1, January-February 2011, pp. 166-174.

Etude du champ magnetique dans les nuages moleculaires

NASA Astrophysics Data System (ADS)

Houde, Martin

2001-12-01

Ce travail est une étude du champ magnétique duns l'environnement circumstellaire des étoiles jeunes. Il a pour origine la certitude qu'avait l'auteur qu'il se devait d'être possible de détecter la présence d'un champ magnétique, et de possiblement le caractériser, par le biais d'observations de profils spectraux d'espèces moléculaires ioniques. Il en découle donc qu'un des buts principaux était de prouver que cela est effectivement possible. La thèse comporte alors des éléments théoriques et expérimentaux qui sont à la fois complémentaires et intimement liés. L'aspect théorique est basé sur l'interaction mutuelle que des particules neutres et chargées peuvent avoir l'une sur l'autre daps un plasma faiblement ionisé comme ceux existants daps les nuages moléculaires sites de formation stellaire. Il appert que la présence d'un champ magnétique a un effet direct sur le comportement des ions (via la force de Lorentz) et indirect sur les molécules neutres (via les nombreuses collisions entre les deux types de particules). Une telle interaction est, comme il est maintenant bien connu, présente dans les premières étapes de la formation dune étoile. Il s'agit bien sûr de la diffusion ambipolaire. Nous montrerons qu'il existe cependant un autre type de diffusion, jusqu'ici inconnue, qui se manifeste plus tard au tours de l'évolution des nuages moléculaires. Celle-ci peut avoir un effet dramatique sur l'apparence des profils spectraux (de rotation moléculaire) des espèces ioniques lorsque comparés à ceux qu'exhibent des espèces neutres coexistantes. Mais pour ce faire, il doit y avoir existence de mouvements organisés (des flots ou jets) de matière ou encore la présence de turbulence dans les régions considérées. Une distribution de vélocité du type maxwellienne ne révèlera pas la présence du champ magnétique. Les observations, qui ont pour but de confirmer la théorie, se situent dans le domaine des longueurs d'ondes millimétriques et sous- millimétriques. Plusieurs espèces moléculaires furent détectées dans un échantillon significatif de nuages moléculaires. L'effet prédit fut confirmé et ce peu importe si les raies observées sont opaques ou transparentes. Dans le dernier chapitre, nous considérerons une application intéressante où nous utiliserons la manifestation de cet effet (ou son manque) pour vérifier l'alignement préférentiel des flots bipolaires, qui accompagnent souvent la présence de proto- étoiles, avec le champ magnétique local.

Assessing specific gravity of young Eucalyptus plantation trees using a resistance drilling technique

Treesearch

José Tarcísio da Silva Oliveira; Xiping Wang; Graziela Baptista Vidaurre

2017-01-01

The resistance drilling technique has been in focus for assessing the specific gravity (SG) of young Eucalyptus trees from plantations for pulpwood production. Namely, the data of 50 34-month-old and 50 62-monthold trees from Eucalyptus grandis × Eucalyptus urophylla clonal plantations was evaluated, while...

Evaluation of new GRACE time-variable gravity data over the ocean

NASA Astrophysics Data System (ADS)

Chambers, Don P.

2006-09-01

Monthly GRACE gravity field models from the three science processing centers (CSR, GFZ, and JPL) are analyzed for the period from February 2003 to April 2005 over the ocean. The data are used to estimate maps of the mass component of sea level at smoothing radii of 500 km and 750 km. In addition to using new gravity field models, a filter has been applied to estimate and remove systematic errors in the coefficients that cause erroneous patterns in the maps of equivalent water level. The filter is described and its effects are discussed. The GRACE maps have been evaluated using a residual analysis with maps of altimeter sea level from Jason-1 corrected for steric variations using the World Ocean Atlas 2001 monthly climatology. The mean uncertainty of GRACE maps determined from an average of data from all 3 processing centers is estimated to be less than 1.8 cm RMS at 750 km smoothing and 2.4 cm at 500 km smoothing, which is better than was found previously using the first generation GRACE gravity fields.

EGSIEM combination service: combination of GRACE monthly K-band solutions on normal equation level

NASA Astrophysics Data System (ADS)

Meyer, Ulrich; Jean, Yoomin; Arnold, Daniel; Jäggi, Adrian

2017-04-01

The European Gravity Service for Improved Emergency Management (EGSIEM) project offers a scientific combination service, combining for the first time monthly GRACE gravity fields of different analysis centers (ACs) on normal equation (NEQ) level and thus taking all correlations between the gravity field coefficients and pre-eliminated orbit and instrument parameters correctly into account. Optimal weights for the individual NEQs are commonly derived by variance component estimation (VCE), as is the case for the products of the International VLBI Service (IVS) or the DTRF2008 reference frame realisation that are also derived by combination on NEQ-level. But variance factors are based on post-fit residuals and strongly depend on observation sampling and noise modeling, which both are very diverse in case of the individual EGSIEM ACs. These variance factors do not necessarily represent the true error levels of the estimated gravity field parameters that are still governed by analysis noise. We present a combination approach where weights are derived on solution level, thereby taking the analysis noise into account.

Ionospheric Density Enhancements at Low and Middle Latitudes during Superstorms Observed from Multiple Satellites

NASA Astrophysics Data System (ADS)

Lei, J.; Wang, W.; Burns, A. G.; Yue, X.

2014-12-01

The total electron content (TEC) data measured by the Jason, CHAMP, GRACE and SAC-C satellites, the in-situ electron densities from CHAMP and GRACE, and the vertical E×B drifts from the ROCSAT satellite are utilized to examine the ionospheric response to superstorms. The combination of observations from multiple satellites provides a unique global view of positive ionospheric storm effect at low and middle latitudes, especially over Oceans and under sunlit conditions during the main phases of the storms. In this talk, we will focus on the morphology, evolution and driving mechanisms of the storm-time ionosphere and explore the relative contributions of the horizontal and vertical transport effects to the observed positive storm phase at different latitudes.

LWS Proposal to Provide Scientific Guidance and Modeling Support for the Ionospheric Mapping Mission. Part 1

NASA Technical Reports Server (NTRS)

Richmond, Arthur D.

2005-01-01

A data assimilation system for specifying the thermospheric density has been developed over the last several years. This system ingests GRACE/CHAMP-type in situ as well as SSULI/SSUSI remote sensing observations while making use of a physical model, the Coupled Thermosphere-Ionosphere Model (CTIM) (Fuller-Rowel1 et al., 1996). The Kalman filter was implemented as the backbone to the data assimilation system, which provides a statistically 'best' estimate as well as an estimate of the error in its state. The system was tested using a simulated thermosphere and observations. CHAMP data were then used to provide the system with a real data source. The results of this study are herein.

Interpretation of the Total Magnetic Field Anomalies Measured by the CHAMP Satellite Over a Part of Europe and the Pannonian Basin

NASA Technical Reports Server (NTRS)

Kis, K. I.; Taylor, Patrick T.; Wittmann, G.; Toronyi, B.; Puszta, S.

2012-01-01

In this study we interpret the magnetic anomalies at satellite altitude over a part of Europe and the Pannonian Basin. These anomalies are derived from the total magnetic measurements from the CHAMP satellite. The anomalies reduced to an elevation of 324 km. An inversion method is used to interpret the total magnetic anomalies over the Pannonian Basin. A three dimensional triangular model is used in the inversion. Two parameter distributions: Laplacian and Gaussian are investigated. The regularized inversion is numerically calculated with the Simplex and Simulated Annealing methods and the anomalous source is located in the upper crust. A probable source of the magnetization is due to the exsolution of the hematite-ilmenite minerals.

Cost-effectiveness of an Evidence-Based Childhood Asthma Intervention in Real-World Primary Care Settings.

PubMed

Dor, Avi; Luo, Qian; Gerstein, Maya Tuchman; Malveaux, Floyd; Mitchell, Herman; Markus, Anne Rossier

We present an incremental cost-effectiveness analysis of an evidence-based childhood asthma intervention (Community Healthcare for Asthma Management and Prevention of Symptoms [CHAMPS]) to usual management of childhood asthma in community health centers. Data used in the analysis include household surveys, Medicaid insurance claims, and community health center expenditure reports. We combined our incremental cost-effectiveness analysis with a difference-in-differences multivariate regression framework. We found that CHAMPS reduced symptom days by 29.75 days per child-year and was cost-effective (incremental cost-effectiveness ratio: $28.76 per symptom-free days). Most of the benefits were due to reductions in direct medical costs. Indirect benefits from increased household productivity were relatively small.

Reprocessing the GRACE-derived gravity field time series based on data-driven method for ocean tide alias error mitigation

NASA Astrophysics Data System (ADS)

Liu, Wei; Sneeuw, Nico; Jiang, Weiping

2017-04-01

GRACE mission has contributed greatly to the temporal gravity field monitoring in the past few years. However, ocean tides cause notable alias errors for single-pair spaceborne gravimetry missions like GRACE in two ways. First, undersampling from satellite orbit induces the aliasing of high-frequency tidal signals into the gravity signal. Second, ocean tide models used for de-aliasing in the gravity field retrieval carry errors, which will directly alias into the recovered gravity field. GRACE satellites are in non-repeat orbit, disabling the alias error spectral estimation based on the repeat period. Moreover, the gravity field recovery is conducted in non-strictly monthly interval and has occasional gaps, which result in an unevenly sampled time series. In view of the two aspects above, we investigate the data-driven method to mitigate the ocean tide alias error in a post-processing mode.

GRACE gravity field recovery using refined acceleration approach

NASA Astrophysics Data System (ADS)

Li, Zhao; van Dam, Tonie; Weigelt, Matthias

2017-04-01

Since 2002, the GRACE mission has yielded monthly gravity field solutions with such a high level of quality that we have been able to observe so many changes to the Earth mass system. Based on GRACE L1B observations, a number of official monthly gravity field models have been developed and published using different methods, e.g. the CSR RL05, JPL RL05, and GFZ RL05 are being computed by a dynamic approach, the ITSG and Tongji GRACE are generated using what is known as the short-arc approach, the AIUB models are computed using celestial mechanics approach, and the DMT-1 model is calculated by means of an acceleration approach. Different from the DMT-1 model, which links the gravity field parameters directly to the bias-corrected range measurements at three adjacent epochs, in this work we present an alternative acceleration approach which connects range accelerations and velocity differences to the gradient of the gravitational potential. Due to the fact that GPS derived velocity difference is provided at a lower precision, we must reduce this approach to residual quantities using an a priori gravity field which allows us to subsequently neglect the residual velocity difference term. We find that this assumption would cause a problem in the low-degree gravity field coefficient, particularly for degree 2 and also from degree 16 to 26. To solve this problem, we present a new way of handling the residual velocity difference term, that is to treat this residual velocity difference term as unknown but estimable quantity, as it depends on the unknown residual gravity field parameters and initial conditions. In other word, we regard the kinematic orbit position vectors as pseudo observations, and the corrections of orbits are estimated together with both the geopotential coefficients and the accelerometer scale/bias by using a weighted least square adjustment. The new approach is therefore a refinement of the existing approach but offers a better approximation to reality. This result is especially important in view of the upcoming GRACE Follow-On mission, which will be equipped with a laser ranging instrument offering a higher precision. Our validation results show that this refined acceleration approach could produce monthly GRACE gravity solutions at the same level of precision as the other approaches.

Application of Satellite Gravimetry for Water Resource Vulnerability Assessment

NASA Technical Reports Server (NTRS)

Rodell, Matthew

2012-01-01

The force of Earth's gravity field varies in proportion to the amount of mass near the surface. Spatial and temporal variations in the gravity field can be measured via their effects on the orbits of satellites. The Gravity Recovery and Climate Experiment (GRACE) is the first satellite mission dedicated to monitoring temporal variations in the gravity field. The monthly gravity anomaly maps that have been delivered by GRACE since 2002 are being used to infer changes in terrestrial water storage (the sum of groundwater, soil moisture, surface waters, and snow and ice), which are the primary source of gravity variability on monthly to decadal timescales after atmospheric and oceanic circulation effects have been removed. Other remote sensing techniques are unable to detect water below the first few centimeters of the land surface. Conventional ground based techniques can be used to monitor terrestrial water storage, but groundwater, soil moisture, and snow observation networks are sparse in most of the world, and the countries that do collect such data rarely are willing to share them. Thus GRACE is unique in its ability to provide global data on variations in the availability of fresh water, which is both vital to life on land and vulnerable to climate variability and mismanagement. This chapter describes the unique and challenging aspects of GRACE terrestrial water storage data, examples of how the data have been used for research and applications related to fresh water vulnerability and change, and prospects for continued contributions of satellite gravimetry to water resources science and policy.

Time-dependent gravity in Southern California, May 1974 to April 1979

NASA Technical Reports Server (NTRS)

Whitcomb, J. H.; Franzen, W. O.; Given, J. W.; Pechmann, J. C.; Ruff, L. J.

1980-01-01

The Southern California gravity survey, begun in May 1974 to obtain high spatial and temporal density gravity measurements to be coordinated with long-baseline three dimensional geodetic measurements of the Astronomical Radio Interferometric Earth Surveying project, is presented. Gravity data was obtained from 28 stations located in and near the seismically active San Gabriel section of the Southern California Transverse Ranges and adjoining San Andreas Fault at intervals of one to two months using gravity meters relative to a base station standard meter. A single-reading standard deviation of 11 microGal is obtained which leads to a relative deviation of 16 microGal between stations, with data averaging reducing the standard error to 2 to 3 microGal. The largest gravity variations observed are found to correlate with nearby well water variations and smoothed rainfall levels, indicating the importance of ground water variations to gravity measurements. The largest earthquake to occur during the survey, which extended to April, 1979, is found to be accompanied in the station closest to the earthquake by the largest measured gravity changes that cannot be related to factors other than tectonic distortion.

A daily wetness index from satellite gravity for near-real time global monitoring of hydrological extremes

NASA Astrophysics Data System (ADS)

Gouweleeuw, Ben; Kvas, Andreas; Gruber, Christian; Mayer-Gürr, Torsten; Flechtner, Frank; Hasan, Mehedi; Güntner, Andreas

2017-04-01

Since April 2002, the Gravity Recovery and Climate Experiment (GRACE) satellite mission has been churning out water storage anomaly data, which has been shown to be a unique descriptor of large-scale hydrological extreme events. Nonetheless, efforts to assess the comprehensive information from GRACE on total water storage variations for near-real time flood or drought monitoring have been limited so far, primarily due to its coarse temporal (weekly to monthly) and spatial (> 150.000 km2) resolution and the latency of standard products of about 2 months,. Pending the status of the aging GRACE satellite mission, the Horizon 2020 funded EGSIEM (European Gravity Service for Improved Emergency Management) project is scheduled to launch a 6 month duration near-real time test run of GRACE gravity field data from April 2017 onward, which will provide daily gridded data with a latency of 5 days. This fast availability allows the monitoring of total water storage variations related to hydrological extreme events, as they occur, as opposed to a 'confirmation after occurrence', which is the current situation. This contribution proposes a global GRACE-derived gridded wetness indicator, expressed as a gravity anomaly in dimensionless units of standard deviation. Results of a retrospective evaluation (April 2002-December 2015) of the proposed index against databases of hydrological extremes will be presented. It is shown that signals for large extreme floods related to heavy/monsoonal rainfall are picked up really well in the Southern Hemisphere and lower Northern Hemisphere (Africa, S-America, Australia, S-Asia), while extreme floods in the Northern Hemisphere (Russia) related to snow melt are often not. The latter is possibly related to a lack of mass movement over longer distances, e.g. when melt water is not drained due to river ice blocking.

Correlating GRACE with Standardized Precipitation Indices and Precipitation Gauges for the High Plains Aquifer

NASA Astrophysics Data System (ADS)

Miller, K. A.; Clancy, K.

2016-12-01

The NASA and German Aerospace Center Gravity Recovery and Climate Experiment (GRACE) detects monthly changes in the gravity of the earth assumed to be water storage using the distance between two satellites, GRACE A and GRACE B, as a phase change. We will use level 3 GRACE Tellus data from the NASA Jet Propulsion Laboratory Physical Oceanography Distributed Active Archive Center (PO.DAAC). The data have a resolution of 9 km2 and are available for 2002 to 2015. We examine GRACE data for the High Plains aquifer (Texas, Oklahoma, Wyoming, Nebraska, Kansas, New Mexico, Colorado and South Dakota) and compare changes to monthly averaged precipitation gauges, standardized precipitation indices for one, three, six, and twelve-months. We hypothesize that GRACE data will correlate best with 1) three-month standardized precipitation indices; 2) regions with natural land cover; 3) and in years where precipitation is at or above average.

Evaluation of GOCE-based global gravity field models over Japan after the full mission using free-air gravity anomalies and geoid undulations

NASA Astrophysics Data System (ADS)

Odera, Patroba Achola; Fukuda, Yoichi

2017-09-01

The performance of Gravity field and steady-state Ocean Circulation Explorer (GOCE) global gravity field models (GGMs), at the end of GOCE mission covering 42 months, is evaluated using geoid undulations and free-air gravity anomalies over Japan, including six sub-regions (Hokkaido, north Honshu, central Honshu, west Honshu, Shikoku and Kyushu). Seventeen GOCE-based GGMs are evaluated and compared with EGM2008. The evaluations are carried out at 150, 180, 210, 240 and 270 spherical harmonics degrees. Results show that EGM2008 performs better than GOCE and related GGMs in Japan and three sub-regions (Hokkaido, central Honshu and Kyushu). However, GOCE and related GGMs perform better than EGM2008 in north Honshu, west Honshu and Shikoku up to degree 240. This means that GOCE data can improve geoid model over half of Japan. The improvement is only evident between degrees 150 and 240 beyond which EGM2008 performs better than GOCE GGMs in all the six regions. In general, the latest GOCE GGMs (releases 4 and 5) perform better than the earlier GOCE GGMs (releases 1, 2 and 3), indicating the contribution of data collected by GOCE in the last months before the mission ended on 11 November 2013. The results indicate that a more accurate geoid model over Japan is achievable, based on a combination of GOCE, EGM2008 and terrestrial gravity data sets. [Figure not available: see fulltext. Caption: Standard deviations of the differences between observed and GGMs implied ( a) free-air gravity anomalies over Japan, ( b) geoid undulations over Japan. n represents the spherical harmonic degrees

CM5, a pre-Swarm comprehensive geomagnetic field model derived from over 12 yr of CHAMP, Ørsted, SAC-C and observatory data

NASA Astrophysics Data System (ADS)

Sabaka, Terence J.; Olsen, Nils; Tyler, Robert H.; Kuvshinov, Alexey

2015-03-01

A comprehensive magnetic field model named CM5 has been derived from CHAMP, Ørsted and SAC-C satellite and observatory hourly-means data from 2000 August to 2013 January using the Swarm Level-2 Comprehensive Inversion (CI) algorithm. Swarm is a recently launched constellation of three satellites to map the Earth's magnetic field. The CI technique includes several interesting features such as the bias mitigation scheme known as Selective Infinite Variance Weighting (SIVW), a new treatment for attitude error in satellite vector measurements, and the inclusion of 3-D conductivity for ionospheric induction. SIVW has allowed for a much improved lithospheric field recovery over CM4 by exploiting CHAMP along-track difference data yielding resolution levels up to spherical harmonic degree 107, and has allowed for the successful extraction of the oceanic M2 tidal magnetic field from quiet, nightside data. The 3-D induction now captures anomalous Solar-quiet features in coastal observatory daily records. CM5 provides a satisfactory, continuous description of the major magnetic fields in the near-Earth region over this time span, and its lithospheric, ionospheric and oceanic M2 tidal constituents may be used as validation tools for future Swarm Level-2 products coming from the CI algorithm and other dedicated product algorithms.

Improving Physical Fitness and Cognitive Functions in Middle School Students: Study Protocol for the Chinese Childhood Health, Activity and Motor Performance Study (Chinese CHAMPS).

PubMed

Zhou, Zhixiong; Dong, Shanshan; Yin, Jun; Fu, Quan; Ren, Hong; Yin, Zenong

2018-05-14

Background : Sedentary lifestyles and their associated harmful consequences are public health concerns that impact more than half of the world's youth population in both developed and developing countries. Methods : The Chinese Childhood Health; Activity and Motor Performance Study (Chinese CHAMPS) was a cluster randomized controlled trial to modify school physical activity policies and the physical education (PE) curriculum; using teacher training and parent engagement to increase opportunities and support students' physical activity and healthy eating. Using a 2 × 2 factorial design, the study tested the incremental effects of increasing the amount and intensity of physical activity, alongside adding support for healthy eating, on health-related and cognitive function outcomes in Chinese middle school students. Results : The intervention was implemented by PE teachers in 12 middle schools in three Chinese cities, with a targeted enrollment of 650 students from August 2015⁻June 2016. The assessment of the outcomes involved a test battery of physical fitness and cognitive functioning at both baseline and at the end of the intervention. Process information on implementation was also collected. Discussion : The Chinese CHAMPS is a multi-level intervention that is designed to test the influences of policy and environmental modifications on the physical activity and eating behaviors of middle school students. It also addresses some key weaknesses in school-based physical activity interventions.

External field characterization using CHAMP satellite data for induction studies

NASA Astrophysics Data System (ADS)

Kunagu, Praveen; Chandrasekhar, E.

2013-06-01

Knowledge of external inducing source field morphology is essential for precise estimation of electromagnetic (EM) induction response. A better characterization of the external source field of magnetospheric origin can be achieved by decomposing it into outer and inner magnetospheric contributions, which are best represented in Geocentric Solar Magnetospheric (GSM) and Solar Magnetic (SM) reference frames, respectively. Thus we propose a spherical harmonic (SH) model to estimate the outer magnetospheric contribution, following the iterative reweighted least squares approach, using the vector magnetic data of the CHAMP satellite. The data covers almost a complete solar cycle from July 2001 to September 2010, spanning 54,474 orbits. The SH model, developed using orbit-averaged vector magnetic data, reveals the existence of a stable outer magnetospheric contribution of about 7.39 nT. This stable field was removed from the CHAMP data after transforming to SM frame. The residual field in the SM frame acts as a primary source for induction in the Earth. The analysis of this time-series using wavelet transformation showed a dominant 27-day periodicity of the geomagnetic field. Therefore, we calculated the inductive EM C-response function in a least squares sense considering the 27-day period variation as the inducing signal. From the estimated C-response, we have determined that the global depth to the perfect substitute conductor is about 1132 km and its conductivity is around 1.05 S/m.

Upper critical field measurements in high-Tc superconducting oxides

NASA Astrophysics Data System (ADS)

Ousset, J. C.; Bobo, J. F.; Ulmet, J. P.; Rakoto, H.; Cheggour, N.

We present upper critical field measurements on the superconducting oxides RE Ba2Cu3O7-δ (RE = Y, Gd) performed in a pulsed magnetic field up to 43 T. Values for Hc2 as high as 52 T and 77 T for Y and Gd respectively, are expected at 77 K. However, in order to observe no resistive behaviour up to 43 T the temperature must be decreased down to 50 K. In the case of oxygen deficient systems the magnetoresistance reveals two superconducting phases wich could be related to two different orders of oxygen vacancies. Nous présentons des mesures de champ critique Hc2 sur les supraconducteurs TR Ba 2Cu3O7-δ (TR = Y, Gd) réalisées en champ magnétique pulsé jusqu'à 43 T. Elles permettent de prévoir des valeurs de H c2 de 52 T et 77 T respectivement pour Y et Gd à 77 K. Cependant, pour ne pas observer de comportement résistif jusqu'au champ maximum, il est nécessaire de refroidir l'échantillon jusqu'à 50 K. Dans le cas des systèmes déficients en oxygène (δ important) nous mettons en évidence l'existence de deux phases supraconductrices qui pourraient être dues à deux ordres différents des lacunes d'oxygène.

CM5, a Pre-Swarm Comprehensive Geomagnetic Field Model Derived from Over 12 Yr of CHAMP, Orsted, SAC-C and Observatory Data

NASA Technical Reports Server (NTRS)

Sabaka, Terence J.; Olsen, Nils; Tyler, Robert H.; Kuvshinov, Alexey

2014-01-01

A comprehensive magnetic field model named CM5 has been derived from CHAMP, Ørsted and SAC-C satellite and observatory hourly-means data from 2000 August to 2013 January using the Swarm Level-2 Comprehensive Inversion (CI) algorithm. Swarm is a recently launched constellation of three satellites to map the Earth's magnetic field. The CI technique includes several interesting features such as the bias mitigation scheme known as Selective Infinite Variance Weighting (SIVW), a new treatment for attitude error in satellite vector measurements, and the inclusion of 3-D conductivity for ionospheric induction. SIVW has allowed for a much improved lithospheric field recovery over CM4 by exploiting CHAMP along-track difference data yielding resolution levels up to spherical harmonic degree 107, and has allowed for the successful extraction of the oceanic M2 tidal magnetic field from quiet, nightside data. The 3-D induction now captures anomalous Solar-quiet features in coastal observatory daily records. CM5 provides a satisfactory, continuous description of the major magnetic fields in the near-Earth region over this time span, and its lithospheric, ionospheric and oceanic M2 tidal constituents may be used as validation tools for future Swarm Level-2 products coming from the CI algorithm and other dedicated product algorithms.

Cost of Incremental Expansion of an Existing Family Medicine Residency Program.

PubMed

Ashkin, Evan A; Newton, Warren P; Toomey, Brian; Lingley, Ronald; Page, Cristen P

2017-07-01

Expanding residency training programs to address shortages in the primary care workforce is challenged by the present graduate medical education (GME) environment. The Medicare funding cap on new GME positions and reductions in the Health Resources and Services Administration (HRSA) Teaching Health Center (THC) GME program require innovative solutions to support primary care residency expansion. Sparse literature exists to assist in predicting the actual cost of incremental expansion of a family medicine residency program without federal or state GME support. In 2011 a collaboration to develop a community health center (CHC) academic medical partnership (CHAMP), was formed and created a THC as a training site for expansion of an existing family medicine residency program. The cost of expansion was a critical factor as no Federal GME funding or HRSA THC GME program support was available. Initial start-up costs were supported by a federal grant and local foundations. Careful financial analysis of the expansion has provided actual costs per resident of the incremental expansion of the residencyRESULTS: The CHAMP created a new THC and expanded the residency from eight to ten residents per year. The cost of expansion was approximately $72,000 per resident per year. The cost of incremental expansion of our residency program in the CHAMP model was more than 50% less than that of the recently reported cost of training in the HRSA THC GME program.

Investigating the polar ionosphere during the development of neutral density enhancements on 24-25 September 2000

NASA Astrophysics Data System (ADS)

Horvath, Ildiko; Lovell, Brian C.

2017-04-01

We focus on the well-known northern daytime neutral density spikes detected by CHAMP on 25 September 2000 and related coupled magnetospheric-ionospheric-thermospheric processes. We investigate the underlying magnetic events and resultant thermospheric variations plus the state of the ionospheric polar region by employing multi-instrument CHAMP and DMSP data. Results show the unfolding of a weak (SYM-HMin ≈ -27 nT; 0345 UT) magnetic storm during which these northern density spikes occurred. Some smaller southern daytime density spikes were also detected prior to this storm on the previous day. All these density spikes were detected in or near polar convection flow channels (FCs). Each FC was characterized by strong antisunward zonal ion drifts that excited the zonal and meridional neutral winds leaving the signature of FC in the CHAMP neutral wind measurements and thus providing direct observational evidence of FC underlying the density spike. Additional to the small-scale field-aligned current (SS-FAC) filaments, the sudden intensifications of ionospheric closure current in the FC fueled the thermosphere and contributed to the development of upwelling and density spike. Some smaller density increases occurred due to the weak intensification of ionospheric closure currents. Equatorward (poleward) directed meridional neutral winds strengthened (weakened) the density spike by moving the neutral density up and along (down and against) the upwelling fueled by the ionospheric closure current and SS-FAC filaments.

Measuring Water Storage in the Amazon

NASA Image and Video Library

2010-07-07

This image is from data taken by NASA Gravity Recovery and Climate Experiment showing the Amazon basin in South America. The amount of water stored in the Amazon basin varies from month to month. Animations are available at the Photojournal.

A new monthly gravity field model based on GRACE observations computed by the modified dynamic approach

NASA Astrophysics Data System (ADS)

Zhou, H.; Luo, Z.; Li, Q.; Zhong, B.

2016-12-01

The monthly gravity field model can be used to compute the information about the mass variation within the system Earth, i.e., the relationship between mass variation in the oceans, land hydrology, and ice sheets. For more than ten years, GRACE has provided valuable information for recovering monthly gravity field model. In this study, a new time series of GRACE monthly solution, which is truncated to degree and order 60, is computed by the modified dynamic approach. Compared with the traditional dynamic approach, the major difference of our modified approach is the way to process the nuisance parameters. This type of parameters is mainly used to absorb low-frequency errors in KBRR data. One way is to remove the nuisance parameters before estimating the geo-potential coefficients, called Pure Predetermined Strategy (PPS). The other way is to determine the nuisance parameters and geo-potential coefficients simultaneously, called Pure Simultaneous Strategy (PSS). It is convenient to detect the gross error by PPS, while there is also obvious signal loss compared with the solutions derived from PSS. After comparing the difference of practical calculation formulas between PPS and PSS, we create the Filter Predetermine Strategy (FPS), which can combine the advantages of PPS and PSS efficiently. With FPS, a new monthly gravity field model entitled HUST-Grace2016s is developed. The comparisons of geoid degree powers and mass change signals in the Amazon basin, the Greenland and the Antarctic demonstrate that our model is comparable with the other published models, e.g., the CSR RL05, JPL RL05 and GFZ RL05 models. Acknowledgements: This work is supported by China Postdoctoral Science Foundation (Grant No.2016M592337), the National Natural Science Foundation of China (Grant Nos. 41131067, 41504014), the Open Research Fund Program of the State Key Laboratory of Geodesy and Earth's Dynamics (Grant No. SKLGED2015-1-3-E).

Champ Lyons: An Incomplete Life

PubMed Central

Dalton, Martin L.

2003-01-01

The life of Champ Lyons, MD, is presented, with emphasis on his tenure as Chairman of the Department of Surgery of the Medical College of Alabama (University of Alabama in Birmingham School of Medicine) from 1950 until 1965. Before becoming chairman Dr. Lyons, as an esteemed microbiologist, participated in the early use of penicillin in wounded servicemen during World War II. Later in his career, he made many contributions to the emerging disciplines of vascular and cardiac surgery. After a brief illness in 1965, Dr. Lyons expired due to a brain tumor. His relatively brief career and his unanticipated sudden demise have lessened the fame of Dr. Lyons to which he is justly entitled. It is the purpose of this presentation to reawaken the surgical community to the importance of this giant of American surgery. PMID:12724636

Transport de Particules et Atmospheres D'etoiles Magnetiques

NASA Astrophysics Data System (ADS)

LeBlanc, Francis

1995-01-01

Les phenomenes relies a la diffusion atomique dans les etoiles sont etudies de facon intensive depuis environ un quart de siecle. La diffusion peut a la fois modifier les abondances atomiques presentes ainsi qu'affecter la structure et l'evolution stellaires. Dans cette these, nous allons etudier trois phenomenes physiques relies a la diffusion. Nous avons developpe la theorie de la derive induite par la radiation afin qu'elle soit facilement applicable dans le contexte de l'astrophysique stellaire. Des calcuis detailles furent effectues afin d'evaluer l'importance de cet effet sur la diffusion relative de l'^3 He et l'^4He et montrent que la derive induite par la radiation accelere la separation de ces deux isotopes dans une etoile de temperature effective de 18000 K. Lorsque l'^4He est present, ce phenomene augmente la vitesse de derive de l'^3He qui migre vers l'exterieur ce qui fait apparai tre la surabondance de cet isotope plus tot dans l'evolution. Des calculs sur le lithium a la base de la zone convective d'une etoile avec une temperature effective de 6700 K monuent que la derive induite par la radiation n'est pas importante dans ce cas. Ce phenomene semble aussi etre negligeable pour l'oxygene dans les etoiles de type A ainsi que pour le mercure dans les etoiles de type B. Deuxiemement nous avons construit des modeles d'atmospheres d'etoiles ayant un champ magnetique horizontal et constant en incluant l'interaction entre ce champ et la diffusion ambipolaire de l'hydrogene. Cette interaction cause une compression de la zone d'ionisation de l'hydrogene. Dans un modele de temperature effective de 10,000 K, et avec log g = 4.0 la gravite effective, c'est-a-dire la gravite plus l'acceleration causee par la force de Lorentz, en presence d'un champ magnetique de 5 kG est sept fois plus grande que la gravite. Ce phenomene affecte donc fortement la structure des etoiles Ap. Cette modification de la structure des etoiles magnetiques cause un plus grand elargissement des raies de Balmer de l'hydrogene. Puisque le champ magnetique observe n'est pas uniforme a la surface des etoiles Ap, la modification de la structure causee par l'interaction entre la diffusion ambipolaire de l'hydrogene et le champ magnetique engendre une variation de l'elargissement des raies de Balmer durant une periode de rotation. La variation causee par ce phenomene est inferieure aux variations observees. D'autres facteurs tels que des gradients horizontaux et verticaux de la metallicite et de la configuration du champ magnetique peuvent aussi influencer la variation des raies de Balmer. Des ameliorations majeures furent apportees au calcul des accelerations radiatives. Grace a des bases de donnees plus completes, il est maintenant possible de calculer l'acceleration causee par la photoionisation. De plus nous avons calcule de maniere approximative l'opacite monochromatique totale qui est un ingredient essentiel au calcul de l'acceleration radiative. Des ameliorations concernant l'elargissement des raies et la distribution de l'acceleration entre les divers ions d'un element furent aussi incluses. Des calculs detailles de l'acceleration radiative sur le fer montrent qu'une abondance consistente avec les observations peut etre supportee dans les etoiles de type A et F. L'abondance de fer supportee depend de la temperature effective et de la gravite de surface de l'etoile. Les accelerations radiatives ont ete tabulees afin d'etre facilement utilisables dans des codes d'evolution stellaire.

La genèse du concept de champ quantique

NASA Astrophysics Data System (ADS)

Darrigol, O.

This is a historical study of the roots of a concept which has proved to be essential in modern particle physics : the concept of quantum field. The first steps were accomplished by two young theoreticians : Pascual Jordan quantized the free electromagnetic field in 1925 by means of the formal rules of the just discovered matrix mechanics, and Paul Dirac quantized the whole system charges + field in 1927. Using Dirac's equation for electrons (1928) and Jordan's idea of quantized matter waves (second quantization), Werner Heisenberg and Wolfgang Pauli provided in 1929-1930 an extension of Dirac's radiation theory and the proof of its relativistic invariance. Meanwhile Enrico Fermi discovered independently a more elegant and pedagogical formulation. To appreciate the degree of historical necessity of the quantization of fields, and the value of contemporaneous critics to this approach, it was necessary to investigate some of the history of the old radiation theory. We present the various arguments however provisional or naïve or wrong they could be in retrospect. So we hope to contribute to a more vivid picture of notions which, once deprived of their historical setting, might seem abstruse to the modern user. Nous présentons une étude historique des origines d'un concept devenu essentiel dans la physique moderne des particules : le concept de champ quantique. Deux jeunes théoriciens franchirent les premières étapes : Pascual Jordan quantifia le champ électromagnétique en 1925 grâce aux règles formelles de la mécanique des matrices naissante, et Paul Dirac quantifia le système complet charges + champ en 1927. Au moyen de l'équation de l'électron de Dirac (1928) et de l'idée de Jordan d'ondes de matière quantifiées (deuxième quantification), Werner Heisenberg et Wolfgang Pauli donnèrent en 1929-1930 une extension de la théorie du rayonnement de Dirac et la preuve de son invariance relativiste. Pendant ce temps Enrico Fermi découvrit indépendamment une formulation plus élégante et plus pédagogique. Pour apprécier le degré de nécessité historique de la quantification des champs et la valeur des critiques contemporaines à cette approche, nous avons dû analyser quelques points de l'histoire de l'ancienne théorie du rayonnement. Nous présentons les divers arguments quelque provisoires, naïfs ou faux qu'ils puissent sembler aujourd'hui. Ainsi nous espérons brosser un tableau plus vivant de notions menacées d'hermétisme si l'on oublie leurs fondements historiques.

The Grace Mission: The Challenges of Using Micron-Level Satellite-to-Satellite Ranging to Measure the Earth's Gravity Field

NASA Technical Reports Server (NTRS)

Watkins, M.; Bettadpur, S.

2000-01-01

The GRACE Mission, to be launched in mid-2001, will provide an unprecedented map of the Earth's gravity field every month. In this paper, we outline the challenges associated with this micron-level satellite-to-satellite ranging, the solutions used by the GRACE project, and the expected science applications of the data.

Probing the Spatio-Temporal Characteristics of Temporal Aliasing Errors and their Impact on Satellite Gravity Retrievals

NASA Astrophysics Data System (ADS)

Wiese, D. N.; McCullough, C. M.

2017-12-01

Studies have shown that both single pair low-low satellite-to-satellite tracking (LL-SST) and dual-pair LL-SST hypothetical future satellite gravimetry missions utilizing improved onboard measurement systems relative to the Gravity Recovery and Climate Experiment (GRACE) will be limited by temporal aliasing errors; that is, the error introduced through deficiencies in models of high frequency mass variations required for the data processing. Here, we probe the spatio-temporal characteristics of temporal aliasing errors to understand their impact on satellite gravity retrievals using high fidelity numerical simulations. We find that while aliasing errors are dominant at long wavelengths and multi-day timescales, improving knowledge of high frequency mass variations at these resolutions translates into only modest improvements (i.e. spatial resolution/accuracy) in the ability to measure temporal gravity variations at monthly timescales. This result highlights the reliance on accurate models of high frequency mass variations for gravity processing, and the difficult nature of reducing temporal aliasing errors and their impact on satellite gravity retrievals.

Seasonal and height variation of gravity wave activities observed by a meteor radar at King Sejong Station (62°S, 57°W), Antarctica

NASA Astrophysics Data System (ADS)

Kim, Y.; Lee, C.; Kim, J.; Choi, J.; Jee, G.

2010-12-01

We have analyzed wind data from individual meteor echoes detected by a meteor radar at King Sejong Station, Antarctica to measure gravity wave activity in the mesopause region. Wind data in the meteor altitudes has been obtained routinely by the meteor radar since its installation in March 2007. The mean variances in the wind data that were filtered for large scale motions (mean winds and tides) can be regarded as the gravity wave activity. Monthly mean gravity wave activities show strong seasonal and height dependences in the altitude range of 80 to 100 km. The gravity wave activities except summer monotonically increase with altitude, which is expected since decreasing atmospheric densities cause wave amplitudes to increase. During summer (Dec. - Feb.) the height profiles of gravity wave activities show a minimum near 90 - 95 km, which may be due to different zonal wind and strong wind shear near 80 - 95 km. Our gravity wave activities are generally stronger than those of the Rothera station, implying sensitive dependency on location. The difference may be related to gravity wave sources in the lower atmosphere near Antarctic vortex.

Repeat Absolute and Relative Gravity Measurements for Geothermal Reservoir Monitoring in the Ogiri Geothermal Field, Southern Kyushu, Japan

NASA Astrophysics Data System (ADS)

Nishijima, J.; Umeda, C.; Fujimitsu, Y.; Takayama, J.; Hiraga, N.; Higuchi, S.

2016-09-01

Repeat hybrid microgravity measurements were conducted around the Ogiri Geothermal Field on the western slope of Kirishima volcano, southern Kyushu, Japan. This study was undertaken to detect the short-term gravity change caused by the temporary shutdown of production and reinjection wells for regular maintenance in 2011 and 2013. Repeat microgravity measurements were taken using an A-10 absolute gravimeter (Micro-g LaCoste) and CG-5 gravimeter (Scintrex) before and after regular maintenance. Both instruments had an accuracy of 10 μgal. The gravity stations were established at 27 stations (two stations for absolute measurements and 25 stations for relative measurements). After removal of noise effects (e.g., tidal movement, precipitation, shallow groundwater level changes), the residual gravity changes were subdivided into five types of response. We detected a gravity decrease (up to 20 μgal) in the reinjection area and a gravity increase (up to 30 μgal) in the production area 1 month after the temporary shutdown. Most of the gravity stations recovered after the maintenance. The temporal density changes in the geothermal reservoir were estimated based on these gravity changes.

Evaluation of EGM2008 Earth Gravitational Model in Algeria using gravity and GPS/levelling data

NASA Astrophysics Data System (ADS)

Benahmed Daho, S. A.

2009-04-01

The present work focuses on the evaluation of the EGM2008 geopotential model that was recently released by the NGA (National Geospatial-Intelligence Agency, U.S)/EGM-development team, in Algeria using the free air gravity anomalies supplied by BGI and GETECH, some of the precise GPS data collected from the international TYRGEONET (TYRhenian GEOdynamical NETwork) and ALGEONET (ALGerian GEOdynamical NETwork) projects and the last Algerian local gravimetric geoid model. Additional comparisons of the terrestrial point data with the corresponding values obtained from other geopotential models were made. Five global geopotential models were used in this comparison: the Preliminary Earth Gravitational Model PGM2007A, the combined CHAMP and GRACE model EIGEN-CG01C, the combined GRACE and LAGEOS model EIGEN-GL04C, OSU91A and EGM96. The study shows that all tested models are an improvement over OSU91A geopotential model used in all previous Algerian geoid computations and that new released combined model (EGM2008) is relatively superior to other tested models in the Algerian region. According to our numerical results, the new EGM2008 model fits better the observed values used in this investigation. Its standard deviations fit with GPS/levelling data are 21.4cm and 18.7cm before and after fitting using four-parameters transformation model. We strongly recommend the use of this new model in the remove-restore technique for the computation of the improved geoid for Algeria. In addition to these more general investigations, special GPS campaign has been performed for altimetric auscultation of a storage tank in which we wanted to test the possibilities to replace levelling by GPS measurements. The evaluation revealed promising results but also that much attention has to be paid on the GPS evaluation method. Key words: Geopotential model, TYRGEONET and ALGEONET projects, GPS/levelling data.

Hybrid Atom Electrostatic System for Satellite Geodesy

NASA Astrophysics Data System (ADS)

Zahzam, Nassim; Bidel, Yannick; Bresson, Alexandre; Huynh, Phuong-Anh; Liorzou, Françoise; Lebat, Vincent; Foulon, Bernard; Christophe, Bruno

2017-04-01

The subject of this poster comes within the framework of new concepts identification and development for future satellite gravity missions, in continuation of previously launched space missions CHAMP, GRACE, GOCE and ongoing and prospective studies like NGGM, GRACE 2 or E-GRASP. We were here more focused on the inertial sensors that complete the payload of such satellites. The clearly identified instruments for space accelerometry are based on the electrostatic technology developed for many years by ONERA and that offer a high level of performance and a high degree of maturity for space applications. On the other hand, a new generation of sensors based on cold atom interferometry (AI) is emerging and seems very promising in this context. These atomic instruments have already demonstrated on ground impressive results, especially with the development of state-of-the-art gravimeters, and should reach their full potential only in space, where the microgravity environment allows long interaction times. Each of these two types of instruments presents their own advantages which are, for the electrostatic sensors (ES), their demonstrated short term sensitivity and their high TRL, and for AI, amongst others, the absolute nature of the measurement and therefore no need for calibration processes. These two technologies seem in some aspects very complementary and a hybrid sensor bringing together all their assets could be the opportunity to take a big step in this context of gravity space missions. We present here the first experimental association on ground of an electrostatic accelerometer and an atomic accelerometer and underline the interest of calibrating the ES instrument with the AI. Some technical methods using the ES proof-mass as the Raman Mirror seem very promising to remove rotation effects of the satellite on the AI signal. We propose a roadmap to explore further in details and more rigorously this attractive hybridization scheme in order to assess its potential for a future geodesy space mission with theoretical and experimental work.

Childhood and Adolescent Migraine Prevention (CHAMP) Study: A Double-blinded, Placebo-controlled, Comparative Effectiveness Study of Amitriptyline, Topiramate and Placebo in the Prevention of Childhood and Adolescent Migraine

PubMed Central

Hershey, Andrew D.; Powers, Scott W.; Coffey, Christopher S.; Eklund, Dixie D.; Chamberlin, Leigh Ann; Korbee, Leslie L.

2013-01-01

Background Migraine is one of the most common health problems for children and adolescents. If not successfully treated, it can impact patients and families with significant disability due to loss of school, work and social function. When headaches become frequent, it is essential to try to prevent the headaches. For children and adolescents this is guided by extrapolation from adult studies, a limited number of small studies in children and adolescents and practitioner preference. The aim of the Childhood and Adolescent Migraine Prevention (CHAMP) study is to determine the most effective preventive agent to use in children and adolescents. Methods CHAMP is a double-blinded, placebo-controlled, multi-center, comparative-effectiveness study of amitriptyline and topiramate for the prevention of episodic and chronic migraine, designed to mirror real-world practice, sponsored by the US National Institute of Neurological Disorders and Stroke/National Institutes of Health (U01NS076788). The study will recruit 675 subjects between the ages of 8 and 17 years old, inclusive, who have migraine with or without aura or chronic migraine as defined by the International Classification of Headache Disorders, 2nd Edition, with at least 4 headaches in the 28 days prior to randomization. The subjects will be randomized in a 2:2:1 (amitriptyline: topiramate: placebo) ratio. Doses are weight based and will be slowly titrated over an 8 week period to a target dose of 1 mg/kg of amitriptyline and 2 mg/kg of topiramate. The primary outcome will be a 50% reduction in headache frequency between the 28 day baseline and the final 28 days of treatment (weeks 20–24). Conclusions The goal of the CHAMP study is to obtain level 1 evidence for the effectiveness of amitriptyline and topiramate in the prevention of migraine in children and adolescents. If this study proves to be positive, it will provide information to the practicing physician as how to best prevent migraine in children and adolescents and subsequently improve the disability and outcomes. PMID:23594025

Gravity changes, soil moisture and data assimilation

NASA Astrophysics Data System (ADS)

Walker, J.; Grayson, R.; Rodell, M.; Ellet, K.

2003-04-01

Remote sensing holds promise for near-surface soil moisture and snow mapping, but current techniques do not directly resolve the deeper soil moisture or groundwater. The benefits that would arise from improved monitoring of variations in terrestrial water storage are numerous. The year 2002 saw the launch of NASA's Gravity Recovery And Climate Experiment (GRACE) satellites, which are mapping the Earth's gravity field at such a high level of precision that we expect to be able to infer changes in terrestrial water storage (soil moisture, groundwater, snow, ice, lake, river and vegetation). The project described here has three distinct yet inter-linked components that all leverage off the same ground-based monitoring and land surface modelling framework. These components are: (i) field validation of a relationship between soil moisture and changes in the Earth's gravity field, from ground- and satellite-based measurements of changes in gravity; (ii) development of a modelling framework for the assimilation of gravity data to constrain land surface model predictions of soil moisture content (such a framework enables the downscaling and disaggregation of low spatial (500 km) and temporal (monthly) resolution measurements of gravity change to finer spatial and temporal resolutions); and (iii) further refining the downscaling and disaggregation of space-borne gravity measurements by making use of other remotely sensed information, such as the higher spatial (25 km) and temporal (daily) resolution remotely sensed near-surface soil moisture measurements from the Advanced Microwave Scanning Radiometer (AMSR) instruments on Aqua and ADEOS II. The important field work required by this project will be in the Murrumbidgee Catchment, Australia, where an extensive soil moisture monitoring program by the University of Melbourne is already in place. We will further enhance the current monitoring network by the addition of groundwater wells and additional soil moisture sites. Ground-based gravity measurements will also be made on a monthly basis at each monitoring site. There will be two levels of modelling and monitoring; regional across the entire Murrumbidgee Catchment (100,000 km2), and local across a small sub-catchment (150 km2).

Fluid lavage of open wounds (FLOW): design and rationale for a large, multicenter collaborative 2 x 3 factorial trial of irrigating pressures and solutions in patients with open fractures.

PubMed

2010-05-06

Open fractures frequently result in serious complications for patients, including infections, wound healing problems, and failure of fracture healing, many of which necessitate subsequent operations. One of the most important steps in the initial management of open fractures is a thorough wound irrigation and debridement to remove any contaminants. There is, however, currently no consensus regarding the optimal approach to irrigating open fracture wounds during the initial operative procedure. The selection of both the type of irrigating fluid and the pressure of fluid delivery remain controversial. The primary objective of this study is to investigate the effects of irrigation solutions (soap vs. normal saline) and pressure (low vs. high; gravity flow vs. high; low vs. gravity flow) on re-operation within one year among patients with open fractures. The FLOW study is a multi-center, randomized controlled trial using a 2 x 3 factorial design. Surgeons at clinical sites in North America, Europe, Australia, and Asia will recruit 2 280 patients who will be centrally randomized into one of the 6 treatment arms (soap + low pressure; soap + gravity flow pressure; soap + high pressure; saline + low pressure; saline + gravity flow pressure; saline + high pressure). The primary outcome of the study is re-operation to promote wound or bone healing, or to treat an infection. This composite endpoint of re-operation includes a narrow spectrum of patient-important procedures: irrigation and debridement for infected wound, revision and closure for wound dehiscence, wound coverage procedures for infected or necrotic wound, bone grafts or implant exchange procedures for established nonunion in patients with postoperative fracture gaps less than 1 cm, intramedullary nail dynamizations in the operating room, and fasciotomies for compartment syndrome. Patients, outcome adjudicators, and data analysts will be blinded. We will compare rates of re-operation at 12 months across soap vs. saline, low pressure vs. high pressure, gravity flow pressure vs. high pressure, and low pressure vs. gravity flow pressure. We will measure function and quality of life with the Short Form-12 (SF-12) and the EuroQol-5 Dimensions (EQ-5D) at baseline, 2 weeks, 6 weeks, 3 months, 6 months, 9 months, and 12 months after initial surgical management, and measure patients' illness beliefs with the Somatic Pre-Occupation and Coping (SPOC) questionnaire at 1 and 6 weeks. We will also compare non-operatively managed infections, wound healing, and fracture healing problems at 12 months after initial surgery. This study represents a major international effort to identify a simple and easily applicable strategy for emergency wound management. The importance of the question and the potential to identify a low cost treatment strategy argues strongly for global participation, especially in low and middle income countries such as India and China where disability from traumatic injuries is substantial. This trial is registered at ClinicalTrials.gov (NCT00788398).

Gravity monitoring of Tatun Volcanic Group activities and inference for underground fluid circulations

NASA Astrophysics Data System (ADS)

Mouyen, Maxime; Chao, Benjamin Fong; Hwang, Cheinway; Hsieh, Wen-Chi

2016-12-01

The Tatun Volcano Group (TVG), located on the northern coast of Taiwan adjacent to the city of Taipei, experiences active hydrothermalism but has no historical record of volcanic eruption. Yet recent studies suggest that TVG is dormant-active rather than extinct. To monitor mass transfers and to gain further understanding of this volcanic area, gravity variations have been recorded continuously since 2012 using a superconducting gravimeter, and once every few months since 2005 using absolute gravimeters. We analyze the continuous gravity time series and propose a model that best explains the gravity variations due to local groundwater redistribution. By correcting these variations, we identify gravity changes as large as 35 μGal that occurred concomitantly to fluid pressure-induced earthquakes and changes in the gas composition at Dayoukeng, one of TVG's fumaroles, over 2005-2007. We examine several fluid movements that can match the gravity observations, yet too few additional constraints exist to favor any of them. In particular, no significant ground displacements are observed when these gravity variations occurred. On the other hand, the model of gravity changes due to local groundwater redistribution can be routinely computed and removed from the ongoing time gravity measurements in order to quickly identify any unusual mass transfer occurring beneath TVG.

Gravity monitoring of Tatun Volcanic Group activities and inference for underground fluid circulations

NASA Astrophysics Data System (ADS)

Mouyen, Maxime; Chao, Benjamin; Hwang, Cheinway; Hsieh, Wen-Chi

2017-04-01

The Tatun Volcano Group (TVG), located on the northern coast of Taiwan adjacent to the city of Taipei, experiences active hydrothermalism but has no historical record of volcanic eruption. Yet recent studies suggest that TVG is dormant-active rather than extinct. To monitor mass transfers and to gain further understanding of this volcanic area, gravity variations have been recorded continuously since 2012 using a superconducting gravimeter, and once every few months since 2005 using absolute gravimeters. We analyze the continuous gravity time series and propose a model that best explain the gravity variations due to local groundwater redistribution. By correcting these variations, we identify gravity changes as large as 35 µGal that occurred concomitantly to fluid pressure-induced earthquakes and changes in the gas composition at Dayoukeng, one of TVG's fumaroles, over 2005-2007. We examine several fluid movements that can match the gravity observations, yet too few additional constraints exist to favor any of them. In particular, no significant ground displacements are observed when these gravity variations occurred. On the other hand, the model of gravity changes due to local groundwater redistribution can be routinely computed and removed from the ongoing time gravity measurements in order to quickly identify any unusual mass transfer occurring beneath TVG.

Sensitivity of Gravity Wave Fluxes to Interannual Variations in Tropical Convection and Zonal Wind.

PubMed

Alexander, M Joan; Ortland, David A; Grimsdell, Alison W; Kim, Ji-Eun

2017-09-01

Using an idealized model framework with high-frequency tropical latent heating variability derived from global satellite observations of precipitation and clouds, the authors examine the properties and effects of gravity waves in the lower stratosphere, contrasting conditions in an El Niño year and a La Niña year. The model generates a broad spectrum of tropical waves including planetary-scale waves through mesoscale gravity waves. The authors compare modeled monthly mean regional variations in wind and temperature with reanalyses and validate the modeled gravity waves using satellite- and balloon-based estimates of gravity wave momentum flux. Some interesting changes in the gravity spectrum of momentum flux are found in the model, which are discussed in terms of the interannual variations in clouds, precipitation, and large-scale winds. While regional variations in clouds, precipitation, and winds are dramatic, the mean gravity wave zonal momentum fluxes entering the stratosphere differ by only 11%. The modeled intermittency in gravity wave momentum flux is shown to be very realistic compared to observations, and the largest-amplitude waves are related to significant gravity wave drag forces in the lowermost stratosphere. This strong intermittency is generally absent or weak in climate models because of deficiencies in parameterizations of gravity wave intermittency. These results suggest a way forward to improve model representations of the lowermost stratospheric quasi-biennial oscillation winds and teleconnections.

Proceedings from the DRG Seminar on Robotics in the Battlefield (31st) Held on 6-8 March 1991 in Paris, France. Volume A (Actes du 31ieme Seminaire sur la Robotique du Champ de Bataille, Groupe sur la Recherche pour la Defense).

DTIC Science & Technology

1992-06-01

que ce que l’on peut esp~rer avec des hommes. Le second serait un robot de renseignement, sorte d’unit6 4 recherche dans la profondeur , mis en place par...3 1ime Seminaire sur la robotique du champ de Bataille Groupe sur la Recherche pour la Defense S92-25111 92 9 14 00O ;-" SANS CLASSIFICATION...6l6mentaires de pilotage d’un v~hicule en vue d’en am~liorer et d’en simplifier la t~l6commandabilit6 by M. Urvoy - Adaptation de l’algorithme A * 6 la

Topside ionospheric irregularities as seen from multisatellite observations

NASA Astrophysics Data System (ADS)

Zakharenkova, Irina; Astafyeva, Elvira

2015-01-01

use in situ data from CHAMP and DMSP satellites, along with data of GPS receiver onboard CHAMP satellite and ground-based GPS receivers to study the occurrence and global distribution of ionospheric irregularities during the main phase of the geomagnetic storm of 29-31 August 2004 (minimum Dst excursion of -128 nT). Using the CHAMP GPS measurements, we created maps of GPS phase fluctuation activity and found two specific zones of the most intense irregularities: (1) the region of the auroral oval at high latitudes of both hemispheres and (2) the low latitudes/equatorial region between Africa and South America. At high latitudes, the topside ionospheric irregularities appeared to be more intensive in the southern hemisphere, which is, most likely, due to seasonal variations in the interhemispheric field-aligned currents system. An analysis of multi-instrumental observations reveals reinforcement of the equatorial ionization anomaly after sunset in Atlantic sector on 30 August and formation of the significant plasma depletions and irregularities over a large longitudinal range. Equatorial irregularities were also found in the morning sector at the recovery phase of the storm. In addition to low Earth orbit (LEO) GPS measurements, we analyze the LEO in situ measurements, and we show that these two techniques cannot be interchangeable in all cases because of the altitudinal extent of plasma irregularities. Overall, we demonstrate that the LEO GPS technique can serve a useful tool for detection of the topside ionospheric irregularities during space weather events and may essentially contribute to other methods based on various instruments.

Textilome abdominal, à propos d'un cas

PubMed Central

Erguibi, Driss; Hassan, Robleh; Ajbal, Mohamed; Kadiri, Bouchaib

2015-01-01

Le textilome, également appelé gossybipomas, est une complication postopératoire très rare. Il peut s'agir d'un corps étranger composé de compresse(s) ou champ(s) chirurgicaux oubliés au niveau d'un foyer opératoire. Ils sont plus souvent asymptomatiques, et difficile à diagnostiquer. En particulier, les cas chroniques ne présentent pas de signes cliniques et radiologiques spécifiques pour le diagnostic différentiel. L'anamnèse est donc indispensable pour le diagnostic vu que les signes cliniques ne sont pas concluants. Le cliché d'abdomen sans préparation est peu contributif, l’échographie est fiable. La tomodensitométrie permet un diagnostic topographique précis, mais ce n'est pas toujours le cas. Certaines équipes proposent des explorations par IRM. Nous rapportons un cas de textilome intra abdominal, chez une patiente de 31 ans opérée il y a 8 ans pour grossesse extra-utérine, chez qui la TDM abdomino-pelvienne a évoqué un kyste hydatique péritonéale sans localisation du foie. Traitée par extrait d'un petit champ de 25x15cm et adhérant au sigmoïde. Le but de ce travail est de mettre en évidence le problème de diagnostic de cette pathologie et l'importance de la laparotomie exploratrice. PMID:26523184

Relative Validity of a Diet History Questionnaire Against a Four-Day Weighed Food Record among Older Men in Australia: The Concord Health and Ageing in Men Project (CHAMP).

PubMed

Rosilene, W V R; Cumming, R; Travison, T; Blyth, F; Naganathan, V; Allman-Farinelli, M; Hirani, V

2015-06-01

To evaluate the relative validity of the diet history questionnaire (DHQ) used in the Concord Health and Ageing in Men Project (CHAMP) against a four-day weighed food record (4dWFR) as the reference method. Detailed DHQ followed by a 4dWFR were completed between July 2012 and October of 2013. Burwood, Canada Bay and Strathfield in Sydney, Australia. Fifty six community- dwelling men aged 75 years and over (mean=79 years). DHQ estimates of intakes were generally higher than estimates from 4dWFR. Differences between the two methods were generally less than 20% with the exception of β-carotene (37%). Fixed and proportional biases were only present for retinol, β-carotene, magnesium, phosphorus and percentage of energy from protein; however, 95% limits of agreement were in some cases wide. Pearson correlation coefficient of log-transformed unadjusted values ranged from 0.15 (zinc) to 0.70 (alcohol), and from 0.06 (iron) to 0.63 (thiamin) after energy-adjustment. Spearman's correlation coefficients ranged from 0.16 (zinc) to 0.80 (alcohol) before energy adjustment, and from 0.15(zinc) to 0.81(alcohol) after energy adjustment. Our findings suggest that the DHQ used in CHAMP to measure the nutritional intake of its participants is appropriate to this age group and provides reasonably similar results to the 4dWFR for the majority of nutrients analysed.

Incorporating prosocial behavior to promote physical activity in older adults: Rationale and design of the Program for Active Aging and Community Engagement (PACE)☆, ☆☆

PubMed Central

Foy, Capri G.; Vitolins, Mara Z.; Case, L. Douglas; Harris, Susan J.; Massa-Fanale, Carol; Hopley, Richard J.; Gardner, Leah; Rudiger, Nicole; Yamamoto, Kathryn; Swain, Brittany; Goff, David C.; Danhauer, Suzanne C.; Booth, Deborah; Gaspari, Jamie

2014-01-01

Despite the benefits of regular physical activity among older adults, physical activity rates are low in this population. The Program for Active Aging and Community Engagement (PACE) is an ongoing randomized controlled trial designed to compare the effects of two interventions on physical activity at 12 months among older adults. A total of 300 men and women aged 55 years or older will be randomized into either a healthy aging (HA) control intervention (n = 150), which is largely based upon educational sessions, or a prosocial behavior physical activity (PBPA) intervention (n = 150), which incorporates structured physical activity sessions, cognitive-behavioral counseling, and opportunities to earn food for donation to a regional food bank based on weekly physical activity and volunteering. The PBPA intervention is delivered at a local YMCA, and a regional grocery store chain donates the food to the food bank. Data will be collected at baseline, 3, 6, and 12 months. The primary outcome is physical activity as assessed by the Community Healthy Activities Model Program for Seniors (CHAMPS) Questionnaire at 12 months. Secondary outcomes include physical function and health-related quality of life. If successful, the PACE study will demonstrate that prosocial behavior and volunteerism may be efficaciously incorporated into interventions and will provide evidence for a novel motivating factor for physical activity. PMID:23876672

Incorporating prosocial behavior to promote physical activity in older adults: rationale and design of the Program for Active Aging and Community Engagement (PACE).

PubMed

Foy, Capri G; Vitolins, Mara Z; Case, L Douglas; Harris, Susan J; Massa-Fanale, Carol; Hopley, Richard J; Gardner, Leah; Rudiger, Nicole; Yamamoto, Kathryn; Swain, Brittany; Goff, David C; Danhauer, Suzanne C; Booth, Deborah; Gaspari, Jamie

2013-09-01

Despite the benefits of regular physical activity among older adults, physical activity rates are low in this population. The Program for Active Aging and Community Engagement (PACE) is an ongoing randomized controlled trial designed to compare the effects of two interventions on physical activity at 12 months among older adults. A total of 300 men and women aged 55 years or older will be randomized into either a healthy aging (HA) control intervention (n = 150), which is largely based upon educational sessions, or a prosocial behavior physical activity (PBPA) intervention (n = 150), which incorporates structured physical activity sessions, cognitive-behavioral counseling, and opportunities to earn food for donation to a regional food bank based on weekly physical activity and volunteering. The PBPA intervention is delivered at a local YMCA, and a regional grocery store chain donates the food to the food bank. Data will be collected at baseline, 3, 6, and 12 months. The primary outcome is physical activity as assessed by the Community Healthy Activities Model Program for Seniors (CHAMPS) Questionnaire at 12 months. Secondary outcomes include physical function and health-related quality of life. If successful, the PACE study will demonstrate that prosocial behavior and volunteerism may be efficaciously incorporated into interventions and will provide evidence for a novel motivating factor for physical activity. © 2013.

In-orbit Calibration Approach of the Microscope Experiment for the Test of the Equivalence Principle at 10-15

NASA Astrophysics Data System (ADS)

Pradels, Grégory

Considering the scientific objectives of the MICROSCOPE space mission, very weak accelerations have to be controlled and measured in orbit. Accelerometers, similar in the concept to the MICROSCOPE instrument, have already characterised the vibration environment on board a satellite at low altitude as well as the fluctuation of drag : analysis of the data provided by the CHAMP mission accelerometer have been performed. By modelling the expected acceleration signals applied on the MICROSCOPE instrument in orbit, the developed analytic model of the mission measurement has shown the interest and the requirements for the instrument calibration. Because of the on-ground seismic perturbations, the instrument cannot be calibrated in laboratory and an in-orbit procedure has to be defined. The proposed approach exploits the drag-free system of the satellite and the sensitivity of the accelerometers. Results obtained from the dedicated simulator of the mission are presented. The goal of the CNES-ESA MICROSCOPE space mission is the test of one of the most famous principle in physics, the Equivalence Principle (EP), basement of General Relativity and which fixes the universality of free fall of all bodies in same gravity field. In the establishment of new theory for Grand Unification, evidence of an EP violation may occur from 10-14 for relative ratio of inertial and gravitational mass between two different materials. The verification by experiment of this theoretical expectation becomes then fundamental. The MICROSCOPE mission is also a technological challenge of a dedicated differential accelerometer able to measure, on board a satellite, very weak accelerations acting on two proof masses made of different materials. In the case of a pure inertial orbit, this specific instrument measures the differential acceleration due to the non uniform Earth gravitational field. With the support of a Drag free system, that reduces the amplitude of the non-gravitational forces applied on the satellite, a spectral density of 10-12 m/s^2/Hz is expected in the frequency range around 10-3 Hz. Then, an accuracy of a few 10-15 m/s^2 can be reached after an integration over 1 day in presence of the 8 m/s^2 Earth gravity field, leading to the EP test with a two orders of magnitude better accuracy than the current laboratory tests. The two ultra sensitive accelerometers, used in combination to build the instrument, are derived from the one flying in the CHAMP space mission which offers for the first time a very fine measurement (10-9 m/s^2/Hz resolution) of the non-gravitational forces applied on a satellite at altitude lower than 500 km. The temporal and spectral analyses confirm the specified intrinsic parameters of the instrument as the bias, the noise level or the thermal sensitivity. A time-frequency analysis provides the first look on disturbances that might occur on this type of satellite : mechanical vibrations after thruster firings, peaks of different amplitudes due to Earth's shadow crossings or effects of the satellite thermal control. A specific and adaptive filter has been developed to reject these perturbations out of the geodesic measurements. After this treatment, the data show some very interesting behaviours as the evolution of the drag with the rotation of the orbit of the satellite. These results are of great interest for the future projects like MICROSCOPE, LISA the space gravity wave antenna developed by NASA and ESA or GOCE the ESA gradiometric solid Earth mission. The MICROSCOPE mission requires not only high resolution for the accelerometers but also fine matching of the parameters because the eventual EP violation signal is detected in the instrument output comparison. The analytic model of the mission measurement demonstrates the necessity of the evaluation of the instrument sensitivity, alignment and coupling with a minimum accuracy of 3 10-4, depending on the relative test mass position, the orbital pointing mode of the satellite, the performance of the drag-free and the attitude control system. This calibration phase is necessary to reject the common mode of the forces applied on the satellite out of the differential measurement. However, the level of the on-ground perturbations in laboratory induced by human activity and seismic noise limits the possibility of a pre- launched calibration. Then, a specific in-orbit procedure has to be defined. The proposed solution consists in exciting the satellite along or about well defined axes with the support of the Drag Free system. Taking into account the measurement range and the resolution of the differential accelerometers, the Drag Free system operation and the electrical thruster performance, the observability of all instrument parameters has been demonstrated with the required accuracy. Different tests of the method are performed with a software dedicated simulator. With an estimation of the Earth's gravitational field and the non-gravitational forces applied to the satellite along the orbit, computed by the "Observatoire de la Côte d'Azur", the validity of this calibration method has been checked for nominal conditions of the satellite operation. The introduction of disturbances like the one observed on the measurements of the CHAMP mission confirms the possibility of an in-orbit calibration with the required accuracy and with the support of the specific filter mentioned below. The MICROSCOPE space mission is of high interest for fundamental physics and exploits for the fist time the combination of a Drag Free system with very high sensitive accelerometer. This system is already selected for other scientific missions like the geodesic mission GOCE which objectives is to map the gravity gradient of the Earth with an accuracy of 4 mEötvös/Hz.

Responses of Myosin Heavy Chain Phenotypes and Gene Expressions in Neck Muscle to Micro- an Hyper-Gravity in Mice

NASA Astrophysics Data System (ADS)

Ohira, Tomotaka; Ohira, Takashi; Kawano, F.; Shibaguchi, T.; Okabe, H.; Ohno, Y.; Nakai, N.; Ochiai, T.; Goto, K.; Ohira, Y.

2013-02-01

Neck muscles are known to play important roles in the maintenance of head posture against gravity. However, it is not known how the properties of neck muscle are influenced by gravity. Therefore, the current study was performed to investigate the responses of neck muscle (rhomboideus capitis) in mice to inhibition of gravity and/or increase to 2-G for 3 months to test the hypothesis that the properties of neck muscles are regulated in response to the level of mechanical load applied by the gravitational load. Three male wild type C57BL/10J mice (8 weeks old) were launched by space shuttle Discovery (STS-128) and housed in Japanese Experimental Module “KIBO” on the International Space Station in mouse drawer system (MDS) project, which was organized by Italian Space Agency. Only 1 mouse returned to the Earth alive after 3 months by space shuttle Atlantis (STS-129). Neck muscles were sampled from both sides within 3 hours after landing. Cage and laboratory control experiments were also performed on the ground. Further, 3-month ground-based control experiments were performed with 6 groups, i.e. pre-experiment, 3-month hindlimb suspension, 2-G exposure by using animal centrifuge, and vivarium control (n=5 each group). Five mice were allowed to recover from hindlimb suspension (including 5 cage control) for 3 months in the cage. Neck muscles were sampled bilaterally before and after 3-month suspension and 2-G exposure, and at the end of 3-month ambulation recovery. Spaceflight-associated shift of myosin heavy chain phenotype from type I to II and atrophy of type I fibers were observed. In response to spaceflight, 17 genes were up-regulated and 13 genes were down-regulated vs. those in the laboratory control. Expression of 6 genes were up-regulated and that of 88 genes were down-regulated by 3-month exposure to 2-G vs. the age-matched cage control. In response to chronic hindlimb suspension, 4 and 20 genes were up- or down-regulated. Further, 98 genes responded significantly to both hindlimb unloading and exposure to 2-G. Thirteen genes were up-regulated and 85 were down-regulated. In conclusion, long-term gravitational unloading of mouse caused shift of fiber phenotype toward fast-twitch type and atrophy of slow-twitch fibers in neck muscle. These responses were closely related to the up- or down-regulation of genes, suggesting that oxidative muscular metabolism may be inhibited in microgravity environment.

Gravity Wave Variances and Propagation Derived from AIRS Radiances

DTIC Science & Technology

2011-04-15

synoptically warm condition and susequently affect ozone depletion (Hamill and Toon, 1991). The importance of gravity waves on climate and weather... troposphere to upper stratosphere can those GWs grow into significant strengths. Locations of high occurrence of convectively generated GWs are also...maximum comes in one month later. A close look at the vertical config- uration of the zonal wind reveals that tropospheric westerlies in the SH high

A modified acceleration-based monthly gravity field solution from GRACE data

NASA Astrophysics Data System (ADS)

Chen, Qiujie; Shen, Yunzhong; Chen, Wu; Zhang, Xingfu; Hsu, Houze; Ju, Xiaolei

2015-08-01

This paper describes an alternative acceleration approach for determining GRACE monthly gravity field models. The main differences compared to the traditional acceleration approach can be summarized as: (1) The position errors of GRACE orbits in the functional model are taken into account; (2) The range ambiguity is eliminated via the difference of the range measurements and (3) The mean acceleration equation is formed based on Cowell integration. Using this developed approach, a new time-series of GRACE monthly solution spanning the period January 2003 to December 2010, called Tongji_Acc RL01, has been derived. The annual signals from the Tongji_Acc RL01 time-series agree well with those from the GLDAS model. The performance of Tongji_Acc RL01 shows that this new model is comparable with the RL05 models released by CSR and JPL as well as with the RL05a model released by GFZ.

Refinement of Earth's gravity field with Topex GPS measurements

NASA Technical Reports Server (NTRS)

Wu, Sien-Chong; Wu, Jiun-Tsong

1989-01-01

The NASA Ocean Topography Experiment satellite TOPEX will carry a microwave altimeter accurate to a few centimeters for the measurement of ocean height. The capability can be fully exploited only if TOPEX altitude can be independently determined to 15 cm or better. This in turn requires an accurate gravity model. The gravity will be tuned with selected nine 10-day arcs of laser ranging, which will be the baseline tracking data type, collected in the first six months of TOPEX flight. TOPEX will also carry onboard an experimental Global Positioning System (GPS) flight receiver capable of simultaneously observing six GPS satellites above its horizon to demonstrate the capability of GPS carrier phase and P-code pseudorange for precise determination of the TOPEX orbit. It was found that subdecimeter orbit accuracy can be achieved with a mere two-hour arc of GPS tracking data, provided that simultaneous measurements are also made at six of more ground tracking sites. The precision GPS data from TOPEX are also valuable for refining the gravity model. An efficient technique is presented for gravity tuning using GPS measurements. Unlike conventional global gravity tuning, this technique solves for far fewer gravity parameters in each filter run. These gravity parameters yield local gravity anomalies which can later be combined with the solutions over other parts of the earth to generate a global gravity map. No supercomputing power will be needed for such combining. The approaches used in this study are described and preliminary results of a covariance analysis presented.

Gravity Probe B

NASA Image and Video Library

2003-07-12

At Vandenberg AFB, the canister enclosing the Gravity Probe B (GP-B) spacecraft is removed from the transporter. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

Gravity Probe B

NASA Image and Video Library

2003-07-12

The Gravity Probe B experiment enters the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

Determining the Ability of Terrestrial Time-Lapse Microgravity Surveying on a Glacier to Find Summer Mass Balance Using Gravitational Modeling

NASA Astrophysics Data System (ADS)

Young, Emma V.

Mass loss of alpine glaciers presently account for about half of the cryospheric contribution to the global sea-level rise. Mass balance of alpine glaciers has predominantly been monitored by; (1) glaciological and hydrological methods, and (2) satellite gravimetric methods using data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellite mission. However, the former can be logistically costly and have large extrapolation errors: measurements taken at monthly temporal scales are expensive and have a spatial resolution of roughly one kilometer. The latter provides monthly mass-balance estimates of aggregates of alpine glaciers, although the spatial resolution ( 300 km) is far too coarse for assessing individual glaciers' mass balance. Ground-based, time-lapse microgravity measurements can potentially overcome some of the disadvantages of the glaciological, hydrological, and satellite gravitational methods for assessing mass changes and their spatial distribution on a single glacier. Gravity models were utilized to predict the gravity signals of the summer-time mass balance, changes in the seasonal snow cover outside of the glacier, and the vertical gravity gradient (VGG) needed for the free-air correction on Wolverine Glacier, AK. The modeled gravity signal of the summer-time mass balance (average of -0.237 mGal) is more than an order of magnitude larger than the uncertainty of conventional relative gravimeters (+/- 0.007 mGal). Therefore, modeling predict that the time-lapse gravitational method could detect the summer-time mass balance on Wolverine Glacier. The seasonal snow effect was shown to have the greatest influence ( -0.15 mGal) on the outer 100 m boundary of the glacier and minimal effect ( -0.02 mGal) towards the center, both larger than the uncertainty of relative gravimeters. The VGG has a positive deviation, about -0.1 to -0.2 mGal/m, from the normal VGG (-0.309 mGal/m). Thus, seasonal snow effect and VGG need to be correctly accounted for when processing gravity measurements to derive the residual gravity signal of the glacier mass balance. Accurate measurements of elevation changes, seasonal snow depth, and the VGG should be performed in future gravity surveys of glaciers.

Textilome abdominal: à propos d'un cas

PubMed Central

Serghini, Issam; El Fikri, Abdelghani; Salim Lalaoui, Jaafar; Zoubir, Mohamed; Boui, Mohammed; Boughanem, Mohamed

2011-01-01

Le textilome est une complication postopératoire très rare mais bien connue. Il peut s'agir d'un corps étranger composé de compresse(s) ou champ(s) chirurgicaux laissés au niveau d'un foyer opératoire. La découverte du textilome abdominale est généralement tardive. L'anamnèse est donc essentielle pour diagnostic vu que la clinique n'est pas concluante. La clinique associe des troubles chroniques du transit à des syndromes sub-occlusifs, le cliché d'abdomen sans préparation est peu contributif. L’échographie est fiable. La tomodensitométrie permet un diagnostic topographique précis. Certaines équipes proposent des explorations par IRM. Nous rapportons un cas de textilome intra abdominale, chez une patiente opérée 6 mois auparavant d'un fibrome utérin. PMID:22355422

Émission spontanée amplifiée (ÉSA) dans une structure à double cavité verticale (Bi-VCSEL)

NASA Astrophysics Data System (ADS)

Boucher, Y.; Gayraud, L.

2004-11-01

Nous présentons une étude théorique de l'Émission Spontanée Amplifiée dans une structure verticale à double cavité, décrite en termes de couplage d'ondes. Chaque cavité y est représentée par un saut de phase, tandis que les puits quantiques sont assimilés à des singularités de Dirac de la permittivité. Les sources sont prises en compte dans le cadre du formalisme des matrices de transfert étendues (3 × 3), qui inclut la saturation des zones actives sous l'effet du champ interne. Dans le plan spectral, celui-ci apparaît, au même titre que le champ émis, filtré par la fonction de transfert bimode de la structure.

Health Status Variation Across Practices in Outpatients With Heart Failure: Insights From the CHAMP-HF (Change the Management of Patients With Heart Failure) Registry.

PubMed

Khariton, Yevgeniy; Hernandez, Adrian F; Fonarow, Gregg C; Sharma, Puza P; Duffy, Carol I; Thomas, Laine; Mi, Xiaojuan; Albert, Nancy M; Butler, Javed; McCague, Kevin; Nassif, Michael E; Williams, Fredonia B; DeVore, Adam; Patterson, J Herbert; Spertus, John A

2018-04-01

Although a key treatment goal for patients with heart failure with reduced ejection fraction is to optimize their health status (their symptoms, function, and quality of life), the variability across outpatient practices in achieving this goal is unknown. In the CHAMP-HF (Change the Management of Patients With Heart Failure) registry, associations between baseline practice characteristics and Kansas City Cardiomyopathy Questionnaire (KCCQ) Overall Summary (OS) and Symptom Frequency (SF) scores were assessed in 3494 patients across 140 US practices using hierarchical regression after accounting for 23 patient and 11 treatment characteristics. We then calculated an adjusted median odds ratio to quantify the average difference in likelihood that a patient would have excellent (KCCQ-OS, ≥75) health status or minimal (monthly or fewer) symptoms (KCCQ-SF, ≥75) when treated at one practice versus another, at random. The mean (±SD) KCCQ-OS and KCCQ-SF were 64.2±24 and 68.9±25.6, with 40% (n=1380) and 50% (n=1760) having KCCQ scores ≥75, respectively. The adjusted median odds ratio across practices, for KCCQ-OS ≥75, was 1.70 (95% confidence interval, 1.54-1.99; P <0.001) indicating a median 70% higher odds of a patient having good-to-excellent health status when treated at one random practice versus another. In regard to KCCQ-SF, the adjusted median odds ratio for KCCQ-SF ≥75 was 1.54 (95% confidence interval, 1.41-1.76; P =0.001). In a large, contemporary registry of outpatients with chronic heart failure with reduced ejection fraction, we observed significant practice-level variability in patients' health status. Quantifying patients' health status as a measure of quality should be explored as a foundation for improving care. URL: https://www.centerwatch.com. Unique identifier: TX144901. © 2018 American Heart Association, Inc.

Monitoring of sporadic plasma layers in the lower ionosphere in the communication link satellite-to-satellite

NASA Astrophysics Data System (ADS)

Pavelyev, Alexander; Matyugov, Stanislav; Wickert, Jens; Liou, Yuei An; Yakovlev, Oleg

Method of global monitoring of sporadic plasma layers in the lower ionosphere is developed. In-vestigations were carried out by use of analysis of the amplitude and phase components of radio holograms obtained during the radio occultation missions CHAMP, FORMOSAT-3. Sporadic amplitude scintillation observed in RO experiments contain important information concerning the seasonal, geographical, and temporal distributions of the ionospheric disturbances and de-pend on solar activity. The geographical and seasonal distributions of sporadic layers in the lower ionosphere as function of solar activity in the period 2002-2008 years is obtained. The general number of RO events with strong amplitude variations can be used as an indicator of the ionospheric activity. We found that during 2001-2008 the daily averaged S4 index measured during CHAllenging Minisatellite Payload (CHAMP) mission depends essentially on solar ac-tivity. The maximum occurred in January 2002, minimum has been observed in summer 2008. Different temporal behavior of S4 index has been detected for polar (with latitude greater than 55 degrees) and low latitude (moderate and equatorial) regions. For polar regions S4 index is slowly decreasing with solar activity. In the low latitude areas S4 index is sharply oscillat-ing, depending on the solar ultraviolet emission variations. The geographical distribution of S4 index variations indicates different origin of ionospheric plasma disturbances in polar and low latitude areas. Origin of the plasma disturbances in the polar areas may be connected with influence of solar wind, the ultraviolet emission of the Sun may be the main cause of the ionospheric irregularities in the low latitude zone. Analysis reveals global oscillations of S4 index with the periods of 5-7 months. Analysis of these oscillations may provide additional connection with solar activity. Therefore, the S4 index of RO signal is important radio physical indicator of solar activity.

Semi-Infinite Geology Modeling Algorithm (SIGMA): a Modular Approach to 3D Gravity

NASA Astrophysics Data System (ADS)

Chang, J. C.; Crain, K.

2015-12-01

Conventional 3D gravity computations can take up to days, weeks, and even months, depending on the size and resolution of the data being modeled. Additional modeling runs, due to technical malfunctions or additional data modifications, only compound computation times even further. We propose a new modeling algorithm that utilizes vertical line elements to approximate mass, and non-gridded (point) gravity observations. This algorithm is (1) magnitudes faster than conventional methods, (2) accurate to less than 0.1% error, and (3) modular. The modularity of this methodology means that researchers can modify their geology/terrain or gravity data, and only the modified component needs to be re-run. Additionally, land-, sea-, and air-based platforms can be modeled at their observation point, without having to filter data into a synthesized grid.

Near-real time orbit determination for the GPS, CHAMP, GRACE, TerraSAR-X, and TanDEM-X satellites

NASA Astrophysics Data System (ADS)

Michalak, Grzegorz; Koenig, Rolf

The GFZ German Research Centre for Geosciences developed a near-real time (NRT) orbit gen-eration system for GPS and Low Earth Orbiting (LEO) satellites to support radio occultation data processing for the CHAMP, GRACE, Terra-SAR-X and the upcoming TanDEM-X mis-sions and fast baseline determination for the TanDEM-X mission. Precise NRT orbits are being generated for the CHAMP and GRACE-A satellites since August 2006 and for TerraSAR-X since August 2007. For each LEO, the system consists of three independent chains delivering NRT orbits with different latencies and accuracies. The first chain generates in a preceding step NRT GPS orbits and clock biases and based thereon LEO orbits with delays of 30 minutes counted from the last measurement point to the time the orbit product is available. The orbit accuracies can be assessed via Satellite Laser Ranging (SLR) to 7 cm. The second chain is based on predicted GPS orbits from the International GNSS Service (IGS) but endowed with in-house estimated clock biases. This chain generates orbits with the same latency of 30 minutes but with better accuracies of 5 cm SLR RMS. The third chain, the least accurate but the fastest, is based on predicted IGS GPS orbits and clocks and delivers LEO orbits with latencies of 13 minutes and accuracies of 10 cm SLR RMS. The system design is such that it can easily be extended to cope with new satellites like TanDEM-X requiring precise and fast available orbits.

Layered superconductors in a parallel field: on the mixed state at equilibrium

NASA Astrophysics Data System (ADS)

Carton, J. P.

1991-01-01

The model describes a set of superconducting planes weakly coupled by Josephson tunnelling. When a magnetic field is applied parallel to the layers and the temperature is low enough so that the interplane coherence length is smaller than the corresponding spacing a, vortex cores fit in between two adjacent planes. In this case the mixed state is studied for high and low fields. The results are consistent with an isosceles triangle picture for the unit cell of the vortex lattice. H_{c1allel} is found to be frac{\\varphi0}{4πλ_Jλ}lnfrac{λ}{a} where λ and λ_J are the two penetration lengths. Le modèle décrit un ensemble de plans supraconducteurs faiblement couplés par effet Josephson. Quand un champ magnétique est appliqué parallèlement aux couches et que la températures est assez basse pour que la longueur de cohérence entre plans soit inférieure à leur distance a, les coeurs de vortex s'ajustent entre deux plans consécutifs. L'état mixte est étudié dans ce cas pour des champs forts et des champs faibles. Les résultats sont compatibles avec un triangle isocèle comme cellule de base du réseau de vortex. On trouve H_{c1allel}=frac{\\varphi0}{4πλ_Jλ}lnλ/a ou λ et λ_J sont les deux longueurs de pénétration.

Synthetic thermosphere winds based on CHAMP neutral and plasma density measurements

NASA Astrophysics Data System (ADS)

Gasperini, F.; Forbes, J. M.; Doornbos, E. N.; Bruinsma, S. L.

2016-04-01

Meridional winds in the thermosphere are key to understanding latitudinal coupling and thermosphere-ionosphere coupling, and yet global measurements of this wind component are scarce. In this work, neutral and electron densities measured by the Challenging Minisatellite Payload (CHAMP) satellite at solar low and geomagnetically quiet conditions are converted to pressure gradient and ion drag forces, which are then used to solve the horizontal momentum equation to estimate low latitude to midlatitude zonal and meridional "synthetic" winds. We validate the method by showing that neutral and electron densities output from National Center for Atmospheric Research (NCAR) Thermosphere Ionosphere Mesosphere Electrodynamics-General Circulation Model (TIME-GCM) can be used to derive solutions to the momentum equations that replicate reasonably well (over 85% of the variance) the winds self-consistently calculated within the TIME-GCM. CHAMP cross-track winds are found to share over 65% of the variance with the synthetic zonal winds, providing further reassurance that this wind product should provide credible results. Comparisons with the Horizontal Wind Model 14 (HWM14) show that the empirical model largely underestimates wind speeds and does not reproduce much of the observed variability. Additionally, in this work we reveal the longitude, latitude, local time, and seasonal variability in the winds; show evidence of ionosphere-thermosphere (IT) coupling, with enhanced postsunset eastward winds due to depleted ion drag; demonstrate superrotation speeds of ˜27 m/s at the equator; discuss vertical wave coupling due the diurnal eastward propagating tide with zonal wave number 3 and the semidiurnal eastward propagating tide with zonal wave number 2.

Global Assimilative Ionospheric Model

DTIC Science & Technology

2002-09-30

CHAMP) and Satelite de Aplicaciones Cientificas-C (SAC-C), as well as from the Ionospheric Occultation Experiment (IOX) instrument developed by...strong interest in future collaborative research. TRANSITIONS Our project is still in its initial stage. No software has been transitioned to

Impedance de surface dans les supraconducteurs quasi-bidimensionnels

NASA Astrophysics Data System (ADS)

Achkir, Driss Brice

Ce travail a caractere experimental et theorique vise l'etude de l'etat supraconducteur de trois familles de composes: les supraconducteurs conventionnels, les organiques et les cuprates YBCO. Pour ce faire, nous avons utilise une technique hyperfrequence, a savoir la mesure d'impedance de surface en fonction de la temperature et du champ magnetique. Dans les supraconducteurs conventionnels, nous avons mesure pour la premiere fois le pic de "coherence" dans la partie reelle de la conductivite. Bien que predit par la theorie BCS, ce pic n'avait pas ete clairement observe en raison de difficultes techniques liees a ce type d'experience. D'autre part, la theorie d'Eliashberg appliquee a la partie reelle de la conductivite du niobium nous a revele l'importance des mesures hyperfrequences pour mieux extraire la partie basse frequence de la densite spectrale alphasp2F(omega). Cette possibilite est attrayante puisque c'est precisement la region de frequences de alphasp2F(omega) ou les donnees d'effet tunnel sont imprecises. Les resultats obtenus sur la longueur de penetration dans les organiques et les cuprates ont permis de montrer que le gap presente des lignes de zeros au niveau de Fermi ou qu'il est, a tout le moins, fortement anisotrope. En effet, la dependance en temperature de la longueur de penetration dans les cristaux purs est lineaire a basse temperature et elle devient quadratique dans les cristaux dopes. Pour le cas des supraconducteurs organiques quasi-bidimensionnels (Et)sb2X, nous avons aussi observe un maximum sur la partie reelle de la conductivite qui n'a rien a voir avec un pic de coherence. Pour ces composes, nous avons effectue une des toutes premieres etudes des fluctuations supraconductrices en temperature et en champ magnetique. Nous montrons que la paraconductivite sigmasp' due aux fluctuations presente un comportement de type Aslamazov-Larkin de nature tridimensionnelle. Ces mesures sont appuyees par les resultats theoriques d'un modele Ginzburg-Landau dynamique que nous avons developpe. De plus, a partir de l'analyse des fluctuations, nous avons pu identifier le champ critique pour la transition resistive en champ et ainsi en deduire la transition de fonte du reseau de vortex dans le (Et)sb2Cu(SCN)sb2.

Superposed epoch analysis of vertical ion velocity, electron temperature, field-aligned current, and thermospheric wind in the dayside auroral region as observed by DMSP and CHAMP

NASA Astrophysics Data System (ADS)

Kervalishvili, G.; Lühr, H.

2016-12-01

This study reports on the results obtained by a superposed epoch analysis (SEA) method applied to the electron temperature, vertical ion velocity, field-aligned current (FAC), and thermospheric zonal wind velocity at high-latitudes in the Northern Hemisphere. The SEA study is performed in a magnetic latitude versus magnetic local time (MLat-MLT) frame. The obtained results are based on observations collected during the years 2001-2005 by the CHAMP and DMSP (F13 and F15) satellites. The dependence on interplanetary magnetic field (IMF) orientations is also investigated using data from the NASA/GSFC's OMNI database. Further, the obtained results are subdivided into three Lloyd seasons of 130 days each, which are defined as follows: local winter (1 January ± 65 days), combined equinoxes (1 April and 1 October ± 32days), and local summer (1 July ± 65 days). A period of 130 days is needed by the CHAMP satellite to pass through all local times. The time and location of the electron temperature peaks from CHAMP measurements near the cusp region are used as the reference parameter for the SEA method to investigate the relationship between the electron temperature and other ionospheric quantities. The SEA derived MLat profiles of the electron temperature show a seasonal dependence, increasing from winter to summer, as expected. But, the temperature rise (difference between the reference temperature peak and the background electron temperature) strongly decreases towards local summer. The SEA derived MLat profiles of the ion vertical velocity at DMSP altitude show the same seasonal behaviour as the electron temperature rice. There exists a clear linear relation between these two variables with a quiet large correlation coefficient value, >0.9. The SEA derived MLat profiles of both, thermospheric zonal wind velocity and FAC, show a clear IMF By orientation dependence for all local seasons. The zonal wind velocity is prominently directed towards west in the MLat-MLT frame for both signs of IMF By, but speeds are larger for positive By. FAC shows a systematic imbalance between downward (upward) and upward (downward) peaks equatorward and poleward of the reference point for positive (negative) IMF By. The influence of upflow events depends strongly on the amplitude of IMF By, to a lesser extend on Bz.

JPL-20180430-GRACFOf-0001-Twin Satellites to Weigh in on Earths Changing Water

NASA Image and Video Library

2018-04-30

GRACE Follow-On (GRACE-FO), successor to the 15-year GRACE mission (Gravity Recovery and Climate Experiment), will map the mass of water as it moves around Earth from month to month and measure the changing amount of water in the atmosphere. This is a video file.

Parallel Observations with Three Superconducting Gravity Sensors During 2014-2015 at Metsähovi Geodetic Research Station, Finland

NASA Astrophysics Data System (ADS)

Virtanen, Heikki; Raja-Halli, Arttu

2017-11-01

The new dual-sphere superconducting gravimeter (SG) OSG-073 was installed at Metsähovi Geodetic Fundamental Station in Southern Finland in February 2014. Its two gravity sensors (N6 and N7) are side by side, not one on top of the other as in other earlier dual-sensor installations. The old SG T020 has been recording continuously since 1994-2016. This instrument is situated in the same room at a distance of 3 m from the dual-sphere SG. T020 observed simultaneously for 1 year with N6 and for 15 months with N7. The gravity signals observed by N6 and N7 are very similar, except for the initial exponential drift. We have calculated the power spectral density to compare the noise level of these instruments with other low noise SGs. In this paper we present the observed differences in the gravity time series of T020 and OSG-073, induced by local hydrology. We have observed a clear 10-20 nms-2 difference in the seasonal gravity variations of OSG-073 and T020. We have found clear gravity differences due to transient effect of heavy precipitation. In addition, we compare the remote effect on gravity due to variations in the Baltic Sea level and total water storage in Finland to the observed gravity signal. We also present modeling results of gravity variations due to local hydrology.

Biomedical Aspects of Lunar and Mars Exploration Missions

NASA Technical Reports Server (NTRS)

Charles, John B.

2006-01-01

Recent long-range planning for exploration-class missions has emphasized the need for anticipating the medical and human factors aspects of such expeditions. Missions returning Americans to the moon for stays of up to 6 months at a time will provide the opportunity to demonstrate the means to function safely and efficiently on another planet. Details of mission architectures are still under study, but a typical Mars design reference mission comprises a six-month transit from Earth to Mars, eighteen months in residence on Mars, and a six-month transit back to Earth. Physiological stresses will come from environmental factors such as prolonged exposure to radiation, weightlessness en route to Mars and then back to Earth, and low gravity and a toxic atmosphere while on Mars. Psychological stressors will include remoteness from Earth, confinement, and potential interpersonal conflicts, all complicated by circadian alterations. Medical risks including trauma must be considered. The role of such risk-modifying influences as artificial gravity and improved propulsion technologies to shorten round-trip time will also be discussed. Results of planning for assuring human health and performance will be presented.

Selection of artificial gravity by animals during suborbital rocket flights.

PubMed

Lange, K O; Belleville, R E; Clark, F C

1975-06-01

White rats selected preferred artificial gravity levels by locomotion in centrifuges consisting of two runways mounted in the nose of sounding rockets. Roll rate of the Aerobee 150A rocket was designed to produce an angular velocity of 45 r.p.m. during 5 min of free-fall, providing a gravity range range from 0.3 to 1.5 G depending on a subject's runway position. One animal was released at the high and one at the low gravity position in each flight. Animal positions were continuously recorded. Flight subjects were selected from about 100 trained animals adapted to the simulated launch environment for several months. In two flights excessive rollrates produced gravity ranges above the designed limits. In two other flights the desired range was produced. Locomotion patterns during these flights were similar. All four animals explored the entire available G-range. One rat settled at 0.4 G after 2 min; the others crossed the 1-G location in progressively narrower excursions and were near earth gravity at the end of the test period. Data were more varible than in laboratory tests above 1 G and the observation periods were necessarily few and short. Tentatively, however, the data suggest that normal earth-reared rats select earth gravity when available magnitudes include values above and below 1 B. Modification of gravity preference by prolonged exposure to higher or lower levels remains a possibility.

Artificial gravity as a countermeasure for mitigating physiological deconditioning during long-duration space missions.

PubMed

Clément, Gilles R; Bukley, Angelia P; Paloski, William H

2015-01-01

In spite of the experience gained in human space flight since Yuri Gagarin's historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of weightlessness on humans. Were astronauts to embark upon a journey to Mars today, the 6-month exposure to weightlessness en route would leave them considerably debilitated, even with the implementation of the suite of piece-meal countermeasures currently employed. Continuous or intermittent exposure to simulated gravitational states on board the spacecraft while traveling to and from Mars, also known as artificial gravity, has the potential for enhancing adaptation to Mars gravity and re-adaptation to Earth gravity. Many physiological functions are adversely affected by the weightless environment of spaceflight because they are calibrated for normal, Earth's gravity. Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth's surface, thereby avoiding the physiological deconditioning that takes place in weightlessness. Because researchers have long been concerned by the adverse sensorimotor effects that occur in weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented.

High Degree and Order Gravity Fields of the Moon Derived from GRAIL Data

NASA Technical Reports Server (NTRS)

Lemoine, F. G.; Goossens, S. J.; Sabaka, T. J.; Nicholas, J. B.; Mazarico, E.; Rowlands, D. D.; Loomis, B. D.; Chinn, D. S.; Caprette, D. S.; McCarthy, J. J.;

Recent results on modelling the spatial and temporal structure of the Earth's gravity field.

PubMed

Moore, P; Zhang, Q; Alothman, A

2006-04-15

The Earth's gravity field plays a central role in sea-level change. In the simplest application a precise gravity field will enable oceanographers to capitalize fully on the altimetric datasets collected over the past decade or more by providing a geoid from which absolute sea-level topography can be recovered. However, the concept of a static gravity field is now redundant as we can observe temporal variability in the geoid due to mass redistribution in or on the total Earth system. Temporal variability, associated with interactions between the land, oceans and atmosphere, can be investigated through mass redistributions with, for example, flow of water from the land being balanced by an increase in ocean mass. Furthermore, as ocean transport is an important contributor to the mass redistribution the time varying gravity field can also be used to validate Global Ocean Circulation models. This paper will review the recent history of static and temporal gravity field recovery, from the 1980s to the present day. In particular, mention will be made of the role of satellite laser ranging and other space tracking techniques, satellite altimetry and in situ gravity which formed the basis of gravity field determination until the last few years. With the launch of Challenging Microsatellite Payload and Gravity and Circulation Experiment (GRACE) our knowledge of the spatial distribution of the Earth's gravity field is taking a leap forward. Furthermore, GRACE is now providing insight into temporal variability through 'monthly' gravity field solutions. Prior to this data we relied on satellite tracking, Global Positioning System and geophysical models to give us insight into the temporal variability. We will consider results from these methodologies and compare them to preliminary results from the GRACE mission.

Aquifer-storage change in the lower Canada del Oro Subbasin, Pima County, Arizona, 1996-98

USGS Publications Warehouse

Pool, D.R.

1999-01-01

Aquifer storage was monitored using gravity methods in the Lower Canada del Oro subbasin from 1996 through 1998 to determine areas of infiltration and amounts of recharge along the Canada del Oro Wash after major surface flow and to estimate aquifer-storage change and specific-yield values for the regional aquifer.  Both purposes were addressed by periodic monitoring of changes in aquifer storage and water levels at a network of gravity stations and monitor wells.  Water levels and gravity were also monitored near an active withdrawal well for several months for the purpose of estimating specific yield of the aquifer within the cone of water-leel depression at the well.

Gravity Probe B

NASA Image and Video Library

2003-07-12

The Gravity Probe B experiment rests on an assembly and test stand in the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

Gravity Probe B

NASA Image and Video Library

2003-07-12

The Gravity Probe B experiment is lowered onto an assembly and test stand in the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

Gravity Probe B

NASA Image and Video Library

2003-07-12

The Gravity Probe B experiment is lifted from its transporter in the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

Gravity Probe B

NASA Image and Video Library

2003-07-12

Enclosed in a canister, the Gravity Probe B (GP-B) spacecraft arrives on Vandenberg Air Force Base, headed for the spacecraft processing facility. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

Gravity Probe B

NASA Image and Video Library

2003-07-12

A transporter carrying the Gravity Probe B experiment backs into the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

ARC-2009-ACD09-0150-007

NASA Image and Video Library

2009-07-22

NASA Research Park (NRP) Timothy Collins, President and Chairman, KleenSpeed Technologies, Inc. and Captain Andrew Butte, rescue helicopter pilot and former Army Aviator, with Butte's 1999 SWIFT. ChampCar Butte has given his racecar to KleenSpeed for conversion to electric.

Orbit determination and gravity field recovery from Doppler tracking data to the Lunar Reconnaissance Orbiter

NASA Astrophysics Data System (ADS)

Maier, Andrea; Baur, Oliver

2016-03-01

We present results for Precise Orbit Determination (POD) of the Lunar Reconnaissance Orbiter (LRO) based on two-way Doppler range-rates over a time span of ~13 months (January 3, 2011 to February 9, 2012). Different orbital arc lengths and various sets of empirical parameters were tested to seek optimal parametrization. An overlap analysis covering three months of Doppler data shows that the most precise orbits are obtained using an arc length of 2.5 days and estimating arc-wise constant empirical accelerations in along track direction. The overlap analysis over the entire investigated time span of 13 months indicates an orbital precision of 13.79 m, 14.17 m, and 1.28 m in along track, cross track, and radial direction, respectively, with 21.32 m in total position. We compare our orbits to the official science orbits released by the US National Aeronautics and Space Administration (NASA). The differences amount to 9.50 m, 6.98 m, and 1.50 m in along track, cross track, and radial direction, respectively, as well as 12.71 m in total position. Based on the reconstructed LRO orbits, we estimated lunar gravity field coefficients up to spherical harmonic degree and order 60. The results are compared to gravity field solutions derived from data collected by other lunar missions.

Intercomparison and Assessment of GRACE Temporal Gravity Solutions Performance

NASA Astrophysics Data System (ADS)

Choe, J.; Nerem, R. S.; Leuliette, E. W.

2006-12-01

The GRACE mission has been producing monthly estimates of changes in the Earth's gravity field since April 2002. Converting the raw GRACE range, accelerometer, and GPS measurements into estimates of the gravity field is a complex process, and therefore different analysis groups use various "recipes" resulting in different models of the time-varying gravity field. We have intercompared the solutions generated by a number of groups: Center for Space Research (CSR), Jet Propulsion Laboratory (JPL), Goddard Space Flight Center (GSFC), Centre National d'Etudes Spatiales (CNES) and GeoForschungsZentrum (GFZ), to determine the characteristics of each group's solutions as applied to different scientific applications. For different scales of gaussian smoothing, we have examined the power spectrum of each model, the pattern of seasonal gravity variations, the residuals from a seasonal fit, and results from locations in the Sahara desert and Atlantic Ocean where the signals are known to be small. We have also characterized the level of "striping" in each center's solutions. In addition, we have compared each center's solutions for changes in Greenland and Antarctic ice mass, global ocean mass, and hydrologic changes over the continents. Using these tests and evaluations, we have been able to characterize the performance of each center's gravity solutions.

Engaging intercollegiate athletes in preventing and intervening in sexual and intimate partner violence.

PubMed

Moynihan, Mary M; Banyard, Victoria L; Arnold, Julie S; Eckstein, Robert P; Stapleton, Jane G

2010-01-01

the object of this exploratory evaluation was to evaluate the "Bringing in the Bystander" sexual and intimate partner violence prevention program with a new sample of intercollegiate athletes. fifty-three male and female athletes participated in the program (experimental group), and 86 were in the control group. All completed pretest, posttest, and 2-month follow-up surveys, including assessment of rape myth acceptance, intent to engage in bystander behaviors, bystander confidence, and bystander behaviors. the program worked overall and for both women and men, improved bystander confidence and intent to engage in bystander behaviors, and did not create significant backlash effects (ie, worsening of attitudes as a result of program). the program fits with the intent of the National Collegiate Athletic Association CHAMPS/Life Skills program regarding its focus on the overall development of student-athletes and demonstrates the promising bystander approach compatible with the 2007 American College Health Association toolkit, Shifting the Paradigm: Primary Prevention of Sexual Violence.

Extracting Ocean-Generated Tidal Magnetic Signals from Swarm Data Through Satellite Gradiometry

NASA Technical Reports Server (NTRS)

Sabaka, Terence J.; Tyler, Robert H.; Olsen, Nils

2016-01-01

Ocean-generated magnetic field models of the Principal Lunar, M2, and the Larger Lunar elliptic, N2, semidiurnal tidal constituents were estimated through a "Comprehensive Inversion" of the first 20.5 months of magnetic measurements from European Space Agency's (ESA) Swarm satellite constellation mission. While the constellation provides important north-south along-track gradiometry information, it is the unique low-spacecraft pair that allows for east-west cross-track gradiometry. This latter type is crucial in delivering an M2 estimate of similar quality with that derived from over 10 years of CHAMP satellite data but over a shorter interval, at higher altitude, and during more magnetically disturbed conditions. Recovered N2 contains nonoceanic signal but is highly correlated with theoretical models in regions of maximum oceanic amplitude. Thus, satellite magnetic gradiometry may eventually enable the monitoring of ocean electrodynamic properties at temporal resolutions of 1 to 2 years, which may have important implications for the inference of ocean temperature and salinity.

Off-Earth Driving Champs in Miles

NASA Image and Video Library

2011-12-07

The total distance driven on Mars by NASA Mars Exploration Rover, 21.35 miles by early December 2011, is approaching the record total for off-Earth driving, held by the robotic Lunokhod 2 rover operated on Earth moon by the Soviet Union in 1973.

Using GoNoodle to Introduce Health Concepts in the K-5 Classroom

ERIC Educational Resources Information Center

Whitney, Elizabeth A.

2016-01-01

This article introduces readers to the GoNoodle platform for incorporating physical activity throughout the school day, and describes how one of the features, Ultimate Champ Training, can be used to teach health concepts in the elementary school classroom.

Genetic Analysis of Mice Skin Exposed by Hyper-Gravity

NASA Astrophysics Data System (ADS)

Takahashi, Rika; Terada, Masahiro; Seki, Masaya; Higashibata, Akira; Majima, Hideyuki J.; Ohira, Yoshinobu; Mukai, Chiaki; Ishioka, Noriaki

2013-02-01

In the space environment, physiological alterations, such as low bone density, muscle weakness and decreased immunity, are caused by microgravity and cosmic radiation. On the other hand, it is known that the leg muscles are hypertrophy by 2G-gravity. An understanding of the effects on human body from microgravity to hyper-gravity is very important. Recently, the Japan Aerospace Exploration Agency (JAXA) has started a project to detect the changes on gene expression and mineral metabolism caused by microgravity by analyzing the hair of astronauts who stay in the international Space Station (ISS) for a long time. From these results of human hair’s research, the genetic effects of human hair roots by microgravity will become clear. However, it is unclear how the gene expression of hair roots was effected by hypergravity. Therefore, in this experiment, we analyzed the effect on mice skin contained hair roots by comparing microgravity or hypergravity exposed mice. The purpose of this experiment is to evaluate the genetic effects on mice skin by microgravity or 2G-gravity. The samples were taken from mice exposed to space flight (FL) or hypergravity environment (2G) for 3-months, respectively. The extracted and amplified RNA from these mice skin was used to DNA microarray analysis. in this experiment, we analyzed the effect of gravity by using mice skin contained hair roots, which exposed space (FL) and hyper-gravity (2G) for 3 months and each control. By DNA microarray analysis, we found the common 98 genes changed in both FL and 2G. Among these 98 genes, the functions and pathways were identified by Gene Ontology (GO) analysis and Ingenuity Pathways Analysis (IPA) software. Next, we focused the one of the identified pathways and compared the effects on each molecules in this pathways by the different environments, such as FL and 2G. As the results, we could detect some interesting molecules, which might be depended on the gravity levels. In addition, to investigate the relationships between genes and protein expression, the proteome analysis was performed. From the result of 2-dimentional electrophoresis, we could detect the some different spots between FL and 2G. These identifications are now in progress using by MALDI-TOF-MS/MS. These results suggested that many genes or proteins on the mice skin might be effected by the different gravity levels.

Microgravity cultivation of cells and tissues

NASA Technical Reports Server (NTRS)

Freed, L. E.; Pellis, N.; Searby, N.; de Luis, J.; Preda, C.; Bordonaro, J.; Vunjak-Novakovic, G.

1999-01-01

In vitro studies of cells and tissues in microgravity, either simulated by cultivation conditions on earth or actual, during spaceflight, are expected to help identify mechanisms underlying gravity sensing and transduction in biological organisms. In this paper, we review rotating bioreactor studies of engineered skeletal and cardiovascular tissues carried out in unit gravity, a four month long cartilage tissue engineering study carried out aboard the Mir Space Station, and the ongoing laboratory development and testing of a system for cell and tissue cultivation aboard the International Space Station.

Viking relativity experiment - Verification of signal retardation by solar gravity

NASA Technical Reports Server (NTRS)

Reasenberg, R. D.; Shapiro, I. I.; Macneil, P. E.; Goldstein, R. B.; Breidenthal, J. C.; Brenkle, J. P.; Cain, D. L.; Kaufman, T. M.; Komarek, T. A.; Zygielbaum, A. I.

1979-01-01

Analysis of 14 months of data obtained from radio ranging to the Viking spacecraft verified, to an estimated accuracy of 0.1%, the prediction of the general theory of relativity that the round-trip times of light signals traveling between the earth and Mars are increased by the direct effect of solar gravity. The corresponding value for the metric parameter gamma is 1.000 plus or minus 0.002, where the quoted uncertainty, twice the formal standard deviation, allows for possible systematic errors.

The Relationship of High-Latitude Thermospheric Wind With Ionospheric Horizontal Current, as Observed by CHAMP Satellite

NASA Astrophysics Data System (ADS)

Huang, Tao; Lühr, Hermann; Wang, Hui; Xiong, Chao

2017-12-01

The relationship between high-latitude ionospheric currents (Hall current and field-aligned current) and thermospheric wind is investigated. The 2-D patterns of horizontal wind and equivalent current in the Northern Hemisphere derived from the CHAMP satellite are considered for the first time simultaneously. The equivalent currents show strong dependences on both interplanetary magnetic field (IMF) By and Bz components. However, IMF By orientation is more important in controlling the wind velocity patterns. The duskside wind vortex as well as the antisunward wind in the morning polar cap is more evident for positive By. To better understand their spatial relation in different sectors, a systematic superposed epoch analysis is applied. Our results show that in the dusk sector, the vectors of the zonal wind and equivalent current are anticorrelated, and both of them form a vortical flow pattern for different activity levels. The currents and zonal wind are intensified with the increase of merging electric field. However, on the dawnside, where the relation is less clear, antisunward zonal winds dominate. Plasma drift seems to play a less important role for the wind than neutral forces in this sector. In the noon sector, the best anticorrelation between equivalent current and wind is observed for a positive IMF By component and it is less obvious for negative By. A clear seasonal effect with current intensities increasing from winter to summer is observed in the noon sector. Different from the currents, the zonal wind intensity shows little dependence on seasons. Our results indicate that the plasma drift and the neutral forces are of comparable influence on the zonal wind at CHAMP altitude in the noon sector.

Characteristics of satellite accelerometer measurements of thermospheric neutral winds at high latitudes

NASA Astrophysics Data System (ADS)

Doornbos, E.; Ridley, A. J.; Cnossen, I.; Aruliah, A. L.; Foerster, M.

2015-12-01

Thermospheric neutral winds play an important part in the coupled thermosphere-ionosphere system at high latitudes. Neutral wind speeds have been derived from the CHAMP and GOCE satellites, which carried precise accelerometers in low Earth orbits. Due to the need to simultaneously determine thermosphere neutral density from the accelerometer in-track measurements, only information on the wind component in the cross-track direction, perpendicular to the flight direction can be derived. However, contrary to ground-based Fabry-Perot interferometer and scanning Doppler imager observations of the thermosphere wind, these satellite-based measurements provide equally distributed coverage over both hemispheres. The sampling of seasonal and local time variations depend on the precession rate of the satellite's orbital plane, with CHAMP covering about 28 cycles of 24-hour local solar time coverage, during its 10 year mission (2000-2010), while the near sun-synchronous orbit of GOCE resulted in a much more limited local time coverage ranging from 6:20 to 8:00 (am and pm), during a science mission duration of 4 years (2009-2013). For this study, the wind data from both CHAMP and GOCE have been analysed in terms of seasonal variations and geographic and geomagnetic local solar time and latitude coordinates, in order to make statistical comparisons for both the Northern and Southern polar areas. The wind data from both satellites were studied independently and in combination, in order to investigate how the strengths and weaknesses of the instruments and orbit parameters of these missions affect investigations of interhemispheric differences. Finally, the data have been compared with results from coupled ionosphere-thermosphere models and from ground-based FPI and SDI measurements.

Radar response to crop residue cover and tillage application on postharvest agricultural surfaces

NASA Astrophysics Data System (ADS)

McNairn, Heather

Les informations sur les pratiques de conservation des sols comme le labourage et la gestion des residus de culture sont requises afin d'estimer avec exactitude les risques d'erosion des sols. Quoique les micro-ondes soient sensibles aux conditions d'humidite et aux proprietes geometriques des surfaces, il n'en demeure pas moins que l'on connait encore peu sur la sensibilite des micro-ondes polarisees lineaires ou des parametres polarimetriques du ROS en fonction des caracteristiques des residus. A partir de donnees prises a l'aide d'un diffusometre monte sur un camion en 1996 et lors d'une mission SIR-C menee en 1994, cette recherche a demontre que les micro-ondes sont sensibles a la fois a la quantite et au type de couverture de residus, de meme qu'a la teneur en eau des residus. La reponse des polarisations croisees lineaires et de plusieurs parametres polarimetriques, incluant la hauteur pedestre, a permis d'observer qu'une diffusion volumique importante avait lieu en presence de vegetation senescente qui se tenait debout et pour les champs non laboures. La diffusion de surface dominait cependant pour les champs avec de faibles quantites de residus et des residus plus fins. La recherche a toutefois demontre que des conditions de surface complexes etaient crees par differentes combinaisons de residus et de pratiques de labourage. Par consequent, il faudra attendre que des donnees multi-polarisees ou polarimetriques soient acquises par les capteurs prevus a bord du satellite canadien RADARSAT-2 et du satellite ENVISAT de l'Agence spatiale europeenne avant de pouvoir completement caracteriser les champs apres la recolte.

GRGM900C: A degree 900 lunar gravity model from GRAIL primary and extended mission data

PubMed Central

Lemoine, Frank G; Goossens, Sander; Sabaka, Terence J; Nicholas, Joseph B; Mazarico, Erwan; Rowlands, David D; Loomis, Bryant D; Chinn, Douglas S; Neumann, Gregory A; Smith, David E; Zuber, Maria T

2014-01-01

We have derived a gravity field solution in spherical harmonics to degree and order 900, GRGM900C, from the tracking data of the Gravity Recovery and Interior Laboratory (GRAIL) Primary (1 March to 29 May 2012) and Extended Missions (30 August to 14 December 2012). A power law constraint of 3.6 ×10−4/ℓ2 was applied only for degree ℓ greater than 600. The model produces global correlations of gravity, and gravity predicted from lunar topography of ≥ 0.98 through degree 638. The model's degree strength varies from a minimum of 575–675 over the central nearside and farside to 900 over the polar regions. The model fits the Extended Mission Ka-Band Range Rate data through 17 November 2012 at 0.13 μm/s RMS, whereas the last month of Ka-Band Range-Rate data obtained from altitudes of 2–10 km fit at 0.98 μm/s RMS, indicating that there is still signal inherent in the tracking data beyond degree 900. PMID:26074638

GRACE time-variable gravity field recovery using an improved energy balance approach

NASA Astrophysics Data System (ADS)

Shang, Kun; Guo, Junyi; Shum, C. K.; Dai, Chunli; Luo, Jia

2015-12-01

A new approach based on energy conservation principle for satellite gravimetry mission has been developed and yields more accurate estimation of in situ geopotential difference observables using K-band ranging (KBR) measurements from the Gravity Recovery and Climate Experiment (GRACE) twin-satellite mission. This new approach preserves more gravity information sensed by KBR range-rate measurements and reduces orbit error as compared to previous energy balance methods. Results from analysis of 11 yr of GRACE data indicated that the resulting geopotential difference estimates agree well with predicted values from official Level 2 solutions: with much higher correlation at 0.9, as compared to 0.5-0.8 reported by previous published energy balance studies. We demonstrate that our approach produced a comparable time-variable gravity solution with the Level 2 solutions. The regional GRACE temporal gravity solutions over Greenland reveals that a substantially higher temporal resolution is achievable at 10-d sampling as compared to the official monthly solutions, but without the compromise of spatial resolution, nor the need to use regularization or post-processing.

GRGM900C: A degree 900 lunar gravity model from GRAIL primary and extended mission data.

PubMed

Lemoine, Frank G; Goossens, Sander; Sabaka, Terence J; Nicholas, Joseph B; Mazarico, Erwan; Rowlands, David D; Loomis, Bryant D; Chinn, Douglas S; Neumann, Gregory A; Smith, David E; Zuber, Maria T

2014-05-28

We have derived a gravity field solution in spherical harmonics to degree and order 900, GRGM900C, from the tracking data of the Gravity Recovery and Interior Laboratory (GRAIL) Primary (1 March to 29 May 2012) and Extended Missions (30 August to 14 December 2012). A power law constraint of 3.6 ×10 -4 / ℓ 2 was applied only for degree ℓ greater than 600. The model produces global correlations of gravity, and gravity predicted from lunar topography of ≥ 0.98 through degree 638. The model's degree strength varies from a minimum of 575-675 over the central nearside and farside to 900 over the polar regions. The model fits the Extended Mission Ka-Band Range Rate data through 17 November 2012 at 0.13 μm/s RMS, whereas the last month of Ka-Band Range-Rate data obtained from altitudes of 2-10 km fit at 0.98 μm/s RMS, indicating that there is still signal inherent in the tracking data beyond degree 900.

GRGM900C: A Degree 900 Lunar Gravity Model from GRAIL Primary and Extended Mission Data

NASA Technical Reports Server (NTRS)

Lemoine, Frank G.; Goossens, Sander; Sabaka, Terence J.; Nicholas, Joseph B.; Mazarico, Erwan; Rowlands, David D.; Bryant, D. Loomis; Chinn, Douglas S.; Neumann, Gregory A.; Smith, David E.;

Use of Absolute Gravity Measurements to Monitor Groundwater in the Española Basin, New Mexico

NASA Astrophysics Data System (ADS)

Cogbill, A. H.; Ferguson, J. F.; Keating, E. H.

2005-05-01

We present early results of three-year project using absolute gravity instrumentation to monitor groundwater in an arid to semi-arid region in northern New Mexico. Over 100 permanent gravity stations have been established in the groundwater basin. A-10 absolute gravity meters, manufactured by Micro-g Solutions, Inc., have been used to monitor long-term gravity changes in the groundwater basin. Over fifty A-10 sites have been established; other gravity sites have been established by reference to the primary A-10 sites using Scintrex CG-3M relative gravimeters. We have used geodetic-quality GPS surveys to directly measure any possible elevation changes at the gravity sites; thus far, no significant changes in elevation have been observed. For the A-10 gravity sites, we have learned that sites must be constructed rather carefully to minimize noise levels due to certain characteristics of the A-10 measurement system. At good sites, away from regions where we expect changes due to groundwater removal, reproducibility of the A-10 measurements is ±4~μGal. To date, we have data from repeat campaigns over a period of 22 months. We have observed systematic changes in gravity of as much as 14~μGal at certain sites. We have directly incorporated gravity modeling into a detailed 3D groundwater model of the basin. On the basis of groundwater modeling, we believe that such gravity changes are due to increased recharge at some sites, as precipitation began to return to normal amounts after a long, pronounced drought about a year into the study. Somewhat surprisingly, no significant gravity changes have been observed at the Buckman Well Field, a spatially small well field that is heavily pumped as a municipal supply field for Santa Fe, New Mexico. One interpretation of this observation is that pumping at the Buckman Field is accessing nearby surface sources rather than groundwater, despite the fact that pumping is occurring from more than 300~m depth.

Einstein's Theory Fights off Challengers

NASA Astrophysics Data System (ADS)

2010-04-01

Two new and independent studies have put Einstein's General Theory of Relativity to the test like never before. These results, made using NASA's Chandra X-ray Observatory, show Einstein's theory is still the best game in town. Each team of scientists took advantage of extensive Chandra observations of galaxy clusters, the largest objects in the Universe bound together by gravity. One result undercuts a rival gravity model to General Relativity, while the other shows that Einstein's theory works over a vast range of times and distances across the cosmos. The first finding significantly weakens a competitor to General Relativity known as "f(R) gravity". "If General Relativity were the heavyweight boxing champion, this other theory was hoping to be the upstart contender," said Fabian Schmidt of the California Institute of Technology in Pasadena, who led the study. "Our work shows that the chances of its upsetting the champ are very slim." In recent years, physicists have turned their attention to competing theories to General Relativity as a possible explanation for the accelerated expansion of the universe. Currently, the most popular explanation for the acceleration is the so-called cosmological constant, which can be understood as energy that exists in empty space. This energy is referred to as dark energy to emphasize that it cannot be directly detected. In the f(R) theory, the cosmic acceleration comes not from an exotic form of energy but from a modification of the gravitational force. The modified force also affects the rate at which small enhancements of matter can grow over the eons to become massive clusters of galaxies, opening up the possibility of a sensitive test of the theory. Schmidt and colleagues used mass estimates of 49 galaxy clusters in the local universe from Chandra observations, and compared them with theoretical model predictions and studies of supernovas, the cosmic microwave background, and the large-scale distribution of galaxies. They found no evidence that gravity is different from General Relativity on scales larger than 130 million light years. This limit corresponds to a hundred-fold improvement on the bounds of the modified gravitational force's range that can be set without using the cluster data. "This is the strongest ever constraint set on an alternative to General Relativity on such large distance scales," said Schmidt. "Our results show that we can probe gravity stringently on cosmological scales by using observations of galaxy clusters." The reason for this dramatic improvement in constraints can be traced to the greatly enhanced gravitational forces acting in clusters as opposed to the universal background expansion of the universe. The cluster-growth technique also promises to be a good probe of other modified gravity scenarios, such as models motivated by higher-dimensional theories and string theory. A second, independent study also bolsters General Relativity by directly testing it across cosmological distances and times. Up until now, General Relativity had been verified only using experiments from laboratory to Solar System scales, leaving the door open to the possibility that General Relativity breaks down on much larger scales. To probe this question, a group at Stanford University compared Chandra observations of how rapidly galaxy clusters have grown over time to the predictions of General Relativity. The result is nearly complete agreement between observation and theory. "Einstein's theory succeeds again, this time in calculating how many massive clusters have formed under gravity's pull over the last five billion years," said David Rapetti of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University and SLAC National Accelerator Laboratory, who led the new study. "Excitingly and reassuringly, our results are the most robust consistency test of General Relativity yet carried out on cosmological scales." Rapetti and his colleagues based their results on a sample of 238 clusters detected across the whole sky by the now-defunct ROSAT X-ray telescope. These data were enhanced by detailed mass measurements for 71 distant clusters using Chandra, and 23 relatively nearby clusters using ROSAT, and combined with studies of supernovas, the cosmic microwave background, the distribution of galaxies and distance estimates to galaxy clusters. Galaxy clusters are important objects in the quest to understand the Universe as a whole. Because the observations of the masses of galaxy clusters are directly sensitive to the properties of gravity, they provide crucial information. Other techniques such as observations of supernovas or the distribution of galaxies measure cosmic distances, which depend only on the expansion rate of the universe. In contrast, the cluster technique used by Rapetti and his colleagues measure in addition the growth rate of the cosmic structure, as driven by gravity. "Cosmic acceleration represents a great challenge to our modern understanding of physics," said Rapetti's co-author Adam Mantz of NASA's Goddard Space Flight Center in Maryland. "Measurements of acceleration have highlighted how little we know about gravity at cosmic scales, but we're now starting to push back our ignorance." The paper by Fabian Schmidt was published in Physics Review D, Volume 80 in October 2009 and is co-authored by Alexey Vikhlinin of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and Wayne Hu of the University of Chicago, Illinois. The paper by David Rapetti was recently accepted for publication in the Monthly Notices of the Royal Astronomical Society and is co-authored by Mantz, Steve Allen of KIPAC at Stanford and Harald Ebeling of the Institute for Astronomy in Hawaii. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

Dissolved oxygen in gravity sewers--measurement and simulation.

PubMed

Gudjonsson, G; Vollertsen, J; Hvitved-Jacobsen, T

2002-01-01

Dissolved oxygen (DO) concentrations were during 2 months continuously measured in an intercepting sewer. Measurements were made upstream and downstream in a 3.6 km gravity sewer. DO showed significant diurnal variations mainly caused by changes in the organic matter composition of the wastewater. At low temperatures the gravity sewer was strictly aerobic. However, towards the end of the measuring campaign, DO concentrations decreased as temperature increased and the sewer became anaerobic part of the day. A conceptual model that takes into account bulk water and biofilm DO uptake as well as reaeration was used to simulate the DO measured. Using measurements from the upstream station as input, the model was calibrated to yield good validation results of the DO at the downstream station.

Identifying high frequency signals in the daily swath mascon solutions from GRACE

NASA Astrophysics Data System (ADS)

Save, H.

2016-12-01

The Gravity Recovery and Climate Experiment (GRACE) mission has provided us with unique information about the total water column in the Earth system over the past 14 years. The GRACE project provides a monthly mean time-variable gravity solution. There has been significant progress in the community over the years to develop shorter time-window gravity solutions. The daily swath mascon solutions, which are under development at the Center for Space Research (CSR), are computed using daily GRACE observation data. This paper discusses the development and the progress of this product. This paper summarizes the analysis of these solutions with special emphasis on identifying the higher frequency natural processes observed by GRACE using these daily swath mascon solutions.

Gravity Probe B

NASA Image and Video Library

2003-07-18

In the spacecraft processing facility on North Vandenberg Air Force Base, workers conduct battery charge/discharge cycles as part of the battery conditioning process on Gravity Probe B. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

Gravity Probe B

NASA Image and Video Library

2003-07-18

In the spacecraft processing facility on North Vandenberg Air Force Base, battery charge/discharge cycles are underway as part of the battery conditioning process on Gravity Probe B. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

C-glycosides from the stems of Calophyllum membranaceum.

PubMed

Zhu, Ling-Juan; Yi, Sen; Li, Xue; Chen, Hai-Feng; Ming, Meng; Zhang, Xue; Yao, Xin-Sheng

2018-01-01

Three new C-glycosides, calophymembransides D-F (1-3), were isolated from the stems of Calophyllum membranaceum Gardn. et Champ.. The structures were assigned on the basis of spectroscopic data. RXRα transcriptional inhibition and α-glucosidase inhibition assays indicated that all the isolates were inactive.

Artificial gravity as a countermeasure for mitigating physiological deconditioning during long-duration space missions

PubMed Central

Clément, Gilles R.; Bukley, Angelia P.; Paloski, William H.

2015-01-01

In spite of the experience gained in human space flight since Yuri Gagarin’s historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of weightlessness on humans. Were astronauts to embark upon a journey to Mars today, the 6-month exposure to weightlessness en route would leave them considerably debilitated, even with the implementation of the suite of piece-meal countermeasures currently employed. Continuous or intermittent exposure to simulated gravitational states on board the spacecraft while traveling to and from Mars, also known as artificial gravity, has the potential for enhancing adaptation to Mars gravity and re-adaptation to Earth gravity. Many physiological functions are adversely affected by the weightless environment of spaceflight because they are calibrated for normal, Earth’s gravity. Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth’s surface, thereby avoiding the physiological deconditioning that takes place in weightlessness. Because researchers have long been concerned by the adverse sensorimotor effects that occur in weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented. PMID:26136665

Two-View Gravity Stress Imaging Protocol for Nondisplaced Type II Supination External Rotation Ankle Fractures: Introducing the Gravity Stress Cross-Table Lateral View.

PubMed

Boffeli, Troy J; Collier, Rachel C; Gervais, Samuel J

Assessing ankle stability in nondisplaced Lauge-Hansen supination external rotation type II injuries requires stress imaging. Gravity stress mortise imaging is routinely used as an alternative to manual stress imaging to assess deltoid integrity with the goal of differentiating type II from type IV injuries in cases without a posterior or medial fracture. A type II injury with a nondisplaced fibula fracture is typically treated with cast immobilization, and a type IV injury is considered unstable and often requires operative repair. The present case series (two patients) highlights a standardized 2-view gravity stress imaging protocol and introduces the gravity stress cross-table lateral view. The gravity stress cross-table lateral view provides a more thorough evaluation of the posterior malleolus owing to the slight external rotation and posteriorly directed stress. External rotation also creates less bony overlap between the tibia and fibula, allowing for better visualization of the fibula fracture. Gravity stress imaging confirmed medial-sided injury in both cases, confirming the presence of supination external rotation type IV or bimalleolar equivalent fractures. Open reduction and internal fixation was performed, and both patients achieved radiographic union. No further treatment was required at 21 and 33 months postoperatively. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

A research about characteristics of longitudinal variations of ES layers irregularities based on CHAMP occultation measurements

NASA Astrophysics Data System (ADS)

Liao, Sunmin

2018-04-01

Based on the data of CHAMP occultation measurements, this paper makes a preliminary analysis of the longitudinal variations of ES irregular structure by using Fourier decomposition and reconstruction technique. It is found that the longitudinal variations of the ES irregular structure show the features of multiple wave-numbers, which is dominated by the wave number 1 to the wave number 5 components, and decrease from the amplitudes of the wave number 6 components. The features of wave number structures are very different in different DIP latitude and different seasons. The number of crests in summer and autumn is mostly 3 or 4 crest structures, while the number of crests in spring achieves 5 at DIP 15°N with small fluctuates, the crests number of winter is the least. In the multiple wave-numbers structure, the wave number 4 component shows a significant dependence on the season, mainly in the summer and autumn, particularly obvious from July to October.

Determination Gradients of the Earth's Magnetic Field from the Measurements of the Satellites and Inversion of the Kursk Magnetic Anomaly

NASA Technical Reports Server (NTRS)

Karoly, Kis; Taylor, Patrick T.; Geza, Wittmann

2014-01-01

We computed magnetic field gradients at satellite altitude, over Europe with emphasis on the Kursk Magnetic Anomaly (KMA). They were calculated using the CHAMP satellite total magnetic anomalies. Our computations were done to determine how the magnetic anomaly data from the new ESA/Swarm satellites could be utilized to determine the structure of the magnetization of the Earths crust, especially in the region of the KMA. Since the ten years of 2 CHAMP data could be used to simulate the Swarm data. An initial East magnetic anomaly gradient map of Europe was computed and subsequently the North, East and Vertical magnetic gradients for the KMA region were calculated. The vertical gradient of the KMA was determined using Hilbert transforms. Inversion of the total KMA was derived using Simplex and Simulated Annealing algorithms. Our resulting inversion depth model is a horizontal quadrangle with upper 300-329 km and lower 331-339 km boundaries.

The oscillation model of hydrothermal dynamics beneath Aso volcano, southwest Japan after small eruption on May 2011: A new understanding model using repeated absolute and relative gravity measurement

NASA Astrophysics Data System (ADS)

Sofyan, Yayan; Nishijima, Jun; Fujimitsu, Yasuhiro; Yoshikawa, Shin; Kagiyama, Tsuneomi; Ohkura, Takahiro

2016-01-01

At the end of 2010, the seismic activity in Aso volcano intensely increased and water level in the Nakadake crater decreased until early in 2011, then was followed by a small eruption in May 2011. After the eruption and heavy rain, the volcanic activity subsided to calm period, crater bottom was refilled with water, and water level increased in the Nakadake crater. The next tremor reappeared in 2014 and tracked to eruption in November 2014. This eruptive pattern and water level variation in the crater repeatedly appeared on the surface, and it should be related to the hydrothermal dynamics beneath Aso volcano. We initiated the gravity measurements in relation to hydrothermal dynamics in the subsurface of Aso volcano using Scintrex CG-5 (549) and LaCoste Romberg type G-1016 relative gravimeter at 28 benchmarks in April 2011, one month before the eruption. The repeated gravity measurements continue to monitor Aso volcano with a series of the measurement after the eruption in every three months to a half year. We analyze the gravity variation from 2011 to 2014 between the time of the phreatic and strombolian eruption. The measurements covered the area more than 60 km2 in the west side of Aso caldera. A new gravity network was also installed in May 2010 at seven benchmarks using A10-017 absolute gravimeter, which re-occupied in October 2010, June 2011 and two benchmarks in June 2014. As a result, the gravity changes distinguish hydrothermal dynamic in the subsurface, which has a direct correlation to water level fluctuation in the crater, after the first eruption and before the second discharge. The monitoring data notice large gravity changes between the surveys at benchmarks around Nakadake crater and Kusasenri area. The simple 3D inversion models of the 4-D gravity data deduce the density contrast distribution beneath Aso volcano. The inversion and mass change result generate the oscillation typical as a new understanding model. The variation of the mass shows a similar trend with the hydrothermal input rate to the crater of past research. The third year monitoring from April 2013 displays a large gravity and mass variation, while precipitation data in this period is smaller than the previous season. The largest increased mass about 43 million tons by Gaussian method occurred between May 2013 and September 2013. According to the three year gravity monitoring, the calm period in Aso volcano happens after May 2011 eruption until September 2013, which is followed by the active period, before the November 2014 eruption. This result will contribute to understand the process of eruption.

Remote Sensing the Thermosphere's State Using Emissions From Carbon Dioxide and Nitric Oxide

NASA Astrophysics Data System (ADS)

Weimer, D. R.; Mlynczak, M. G.; Doornbos, E.

2017-12-01

Measurements of emissions from nitric oxide and carbon dioxide in the thermosphere have strong correlations with properties that are very useful to the determination of thermospheric densities. We have compared emissions measured with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite with neutral density measurements from the Challenging Mini-satellite Payload (CHAMP), the Gravity Recovery and Climate Experiment (GRACE), the Ocean Circulation Explorer (GOCE), and the three Swarm satellites, spanning a time period of over 15 years. It has been found that nitric oxide emissions match changes in the exospheric temperatures that have been derived from the densities through use of the Naval Reasearch Laboratory Mass Spectrometer, Incoherent Scatter Radar Extended Model (NRLMSISE-00) thermosphere model. Similarly, our results indicate that the carbon dioxide emissions have annual and semiannual oscillations that correlate with changes in the amount of oxygen in the thermosphere, also determined by use of the NRLMSISE-00 model. These annual and semi-annual variations are found to have irregular amplitudes and phases, which make them very difficult to accurately predict. Prediction of exospheric temperatures through the use of geomagnetic indices also tends to be inexact. Therefore, it would be possible and very useful to use measurements of the thermosphere's infrared emissions for real-time tracking of the thermosphere's state, so that more accurate calculations of the density may be obtained.

Contribution to the Study of Regional Magnetization of Satellite Magnetic Measurement: Magsat, Orsted, and Champ (with Gravity Field)

NASA Technical Reports Server (NTRS)

Taylor, Patrick T.

2004-01-01

A discussion of and introduction to satellite-altitude geopotential field studies and their interpretation with emphasis on results from metalliferous regions will be given. The magnetic and gravimetric measurements from satellite altitudes show heterogeneity in deeper parts of the lithosphere. These patterns of magnetic anomalies do not only reveal the largest iron ore deposits such as Kiruna, Sweden, Kursk, Russia, and Banugi, Central African Republic but also linear features indicating structural discontinuities. Changes of magnetic amplitude of these patterns are caused by intersecting transverse fractures localizing magmatism and concentration of metals. In addition satellite altitude data are related to variations in crustal thickness and heat flow. Deep-rooted structural discontinuities, defined by combination of geological and geophysical criteria, with spacing of several hundred kilometers, reveal a quite uniform pattern in the deeper parts of the lithosphere. As these structures provide favorable pathways for the ascent of heat, magmas and ore-forming fluids, their recognition is of crucial importance and can be used in the compilation of a new type of mineral prognosis map. An example from Europe includes a pattern of east west trending structural discontinuities or belts and their junction with the NW-trending Tornqvist-Teisseyre Line. The Upper Silesian-Cracovian Zn-Pb district occurs along one of the latitudinal belts. Leslaw Teper of the University of Silesia has been invited to show the fractures in crystalline basement beneath the sediments hosting the Zn-Pb ores.

Recent observations of traveling ionospheric disturbances and plasma bubbles using Optical Mesosphere Thermosphere Imagers in Asian and African sectors

NASA Astrophysics Data System (ADS)

Shiokawa, K.; Otsuka, Y.; Tsuchiya, S.; Moral, A. C.; Okoh, D.

2017-12-01

We review recent observational results of medium-scale traveling ionospheric disturbances (MSTIDs) and equatorial plasma bubbles obtained by using airglow imagers and Fabry-Perot interferometers of the Optical Mesosphere Thermosphere Imagers (OMTIs) at Asian and African sectors. The OMTIs contains 20 airglow imagers and 5 Fabry-Perot interferometers (FPIs) at Canada, USA (Alaska), Russia, Finland, Norway, Iceland, Japan, Thailand, Indonesia, Australia, and Nigeria (http://stdb2.isee.nagoya-u.ac.jp/omti/). The 3-dimentional Fast Fourier Transformation of airglow images makes it possible to analyze 16-year airglow images obtained at Shigaraki (34.8N) and Rikubetsu (43.5N), Japan, to obtain phase velocity spectra of gravity waves and MSTIDs. The MSTIDs spectra show clear southwestward preference of propagation and minor northeastward propagation over Japan. We also found clear negative correlation between MSTID power and solar F10.7 flux, indicating that MSTIDs becomes more active during solar quiet time. This fact suggest the control of ionospheric Perkins and E-F coupling instabilities by solar activities. Three TIDs in airglow images over Indonesia, including midnight brightness waves (MBWs), were compared with CHAMP-satellite overpass to investigate neutral density variations in the thermosphere associated with the TIDs. We found clear correspondence in variations between the airglow intensities and neutral densities, suggesting that the observed TIDs over the equatorial region is caused by gravity waves. We also compare average thermospheric temperatures measured by the four FPIs for 3-4 years with the MSIS90E and GAIA models. The comparison shows that GAIA generally shows better fitting than the MSIS90E, but at the equatorial stations, GAIA tends to fail to reproduce the FPI temperature, probably due to ambiguity of location of the midnight temperature maximum. We also made statistics of plasma bubble occurrence using airglow imager and GNSS receiver at Abuja (9.0N), Nigeria near the geomagnetic equator based on 1.6 year observations. The bubble occurrence is high at equinoxes. There are 33 % of events for which bubble detection by airglow image and GNSS ROTI is different. We discuss possible cause of these differences in the presentation.

The Spatial-Temporal Characteristics of Air Pollution in China from 2001–2014

PubMed Central

Bao, Junzhe; Yang, Xiping; Zhao, Zhiyuan; Wang, Zhenkun; Yu, Chuanhua; Li, Xudong

2015-01-01

To provide some useful information about the control of air pollution in China, we studied the spatial-temporal characteristics of air pollution in China from 2001–2014. First, we drew several line charts and histograms of the Air Pollution Index (API) and Air Quality Index (AQI) of 31 capital cities and municipalities to research the distribution across different times and cities; then, we researched the spatial clustering of API and AQI; finally, we examined the shift of the gravity center of API and AQI in different years and months. The API values had a decreasing trend: the high values had a clustering trend in some northern cities, and the low values had a clustering trend in some southern cities. The AQI values were relatively low, from 15:00–17:00 during the day. The gravity center of API had a trend of moving south from 2001–2003, then fluctuated in an unordered pattern and moved north in the winter. The AQI gravity center did not have a regular shift during different months. In conclusion, the government should take action to mitigate air pollution in some typical cities, as well as air pollution during the winter. PMID:26694427

Tropical Gravity Wave Momentum Fluxes and Latent Heating Distributions

NASA Technical Reports Server (NTRS)

Geller, Marvin A.; Zhou, Tiehan; Love, Peter T.

2015-01-01

Recent satellite determinations of global distributions of absolute gravity wave (GW) momentum fluxes in the lower stratosphere show maxima over the summer subtropical continents and little evidence of GW momentum fluxes associated with the intertropical convergence zone (ITCZ). This seems to be at odds with parameterizations forGWmomentum fluxes, where the source is a function of latent heating rates, which are largest in the region of the ITCZ in terms of monthly averages. The authors have examined global distributions of atmospheric latent heating, cloud-top-pressure altitudes, and lower-stratosphere absolute GW momentum fluxes and have found that monthly averages of the lower-stratosphere GW momentum fluxes more closely resemble the monthly mean cloud-top altitudes rather than the monthly mean rates of latent heating. These regions of highest cloud-top altitudes occur when rates of latent heating are largest on the time scale of cloud growth. This, plus previously published studies, suggests that convective sources for stratospheric GW momentum fluxes, being a function of the rate of latent heating, will require either a climate model to correctly model this rate of latent heating or some ad hoc adjustments to account for shortcomings in a climate model's land-sea differences in convective latent heating.

VANDENBERG AFB, CALIF. - Logos identify the mission of this Delta II rocket that will launch the Gravity Probe B experiment, developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-12

VANDENBERG AFB, CALIF. - Logos identify the mission of this Delta II rocket that will launch the Gravity Probe B experiment, developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The targeted launch date is Dec. 6, 2003.

Radial and tangential gravity rates from GRACE in areas of glacial isostatic adjustment

NASA Astrophysics Data System (ADS)

van der Wal, Wouter; Kurtenbach, Enrico; Kusche, Jürgen; Vermeersen, Bert

2011-11-01

In areas dominated by Glacial Isostatic Adjustment (GIA), the free-air gravity anomaly rate can be converted to uplift rate to good approximation by using a simple spectral relation. We provide quantitative comparisons between gravity rates derived from monthly gravity field solutions (GFZ Potsdam, CSR Texas, IGG Bonn) from the Gravity Recovery and Climate Experiment (GRACE) satellite mission with uplift rates measured by GPS in these areas. The band-limited gravity data from the GRACE satellite mission can be brought to very good agreement with the point data from GPS by using scaling factors derived from a GIA model (the root-mean-square of differences is 0.55 mm yr-1 for a maximum uplift rate signal of 10 mm yr-1). The root-mean-square of the differences between GRACE derived uplift rates and GPS derived uplift rates decreases with increasing GRACE time period to a level below the uncertainty that is expected from GRACE observations, GPS measurements and the conversion from gravity rate to uplift rate. With the current length of time-series (more than 8 yr) applying filters and a hydrology correction to the GRACE data does not reduce the root-mean-square of differences significantly. The smallest root-mean-square was obtained with the GFZ solution in Fennoscandia and with the CSR solution in North America. With radial gravity rates in excellent agreement with GPS uplift rates, more information on the GIA process can be extracted from GRACE gravity field solutions in the form of tangential gravity rates, which are equivalent to a rate of change in the deflection of the vertical scaled by the magnitude of gravity rate vector. Tangential gravity rates derived from GRACE point towards the centre of the previously glaciated area, and are largest in a location close to the centre of the former ice sheet. Forward modelling showed that present day tangential gravity rates have maximum sensitivity between the centre and edge of the former ice sheet, while radial gravity rates are most sensitive in the centre of the former ice sheet. As a result, tangential gravity rates offer constraints on a two-layer mantle viscosity profile that are different from radial gravity rates, which can be exploited in future GIA studies.

Effects of simulated increased gravity on the rate of aging of rats - Implications for the rate of living theory of aging

NASA Technical Reports Server (NTRS)

Economos, A. C.; Ballard, R. C.; Blunden, M.; Miquel, J.; Lindseth, K. A.; Fleming, J.; Philpott, D. E.; Oyama, J.

1982-01-01

It was found that the rate of aging of 17 month old rats which had been exposed to 3.14 times normal gravity in an animal centrifuge for 8 months was larger than that of the controls as determined by the apparently elevated lipofuscin content in heart and kidney, reduced numbers and increased size of mitochondria of heart tissue, and inferior liver mitochondria respiration. Steady-state food intake per day per kg body weight, which is presumably proportional to rate of living or specific basal metabolic expenditure, was found to be about 18 percent higher than in the controls after an initial 2 month adaptation period. Although half of the centrifuged animals lived only a little shorter than the controls (average about 343 vs. 364 days on the average, statistically nonsignificant), the remaining half (longest survivors) lived on the centrifuge an average of 520 days (range 483-572) compared to an average of 574 days (range 502-615) for the controls, computed from the onset of centrifugation, or 11 percent shorter. These findings indicate that a moderate increase of the level of basal metabolism of young adult rats adapted to hypergravity compared to controls in normal gravity is accompanied by a roughly similar increase in the rate of organ aging and reduction of survival, in agreement with Pearl's (1928) rate of living theory of aging, previously experimentally demonstrated only in poikilotherms.

First results of the EGSIEM Near Real-Time Service

NASA Astrophysics Data System (ADS)

Kvas, Andreas; Gruber, Christian; Gouweleeuw, Ben; Chen, Qiang; Poropat, Lea; Flechtner, Frank; Mayer-Gürr, Torsten; Güntner, Andreas

2017-04-01

To enable the use of GRACE and GRACE-FO earth observation data for rapid monitoring applications, the Horizon2020 funded EGSIEM (European Gravity Service for Improved Emergency Management) project has established a demonstrator for a near real-time (NRT) gravity field service. The service aims to increase the temporal resolution of mass transport products from one month to one day and to reduce the latency from currently two months to five days. This allows the monitoring of hydrological extreme events as they occur, in contrast to a 'confirmation after occurrence' as is the situation today. The service will be jointly run by GFZ (German Research Centre for Geosciences) and Graz University of Technology, with each analysis center providing an independent solution. On-line validation will be performed by the University of Luxembourg using GNSS loading. A six-month long operational test run of the service starting in April 2017 is planned, in case GRACE Quick-Look data (provided by JPL) is still available. Within this time period, daily gravity field solutions serve as input to the EGSIEM Hydrological Service, which derives flood and drought indicators to be used within DLR's Center for Satellite Based Crisis Information and the Global Flood Awareness System (GloFAS). This contribution highlights the current status of the NRT service and the results of the preparation phase. The performance of the NRT mass transport products will be shown by comparison with independent GNSS loading and ocean bottom pressure data as well as as catchment aggregated values for hydrological extreme events.

Understanding Characteristics of Families Who Buy Local Produce

ERIC Educational Resources Information Center

Racine, Elizabeth F.; Mumford, Elizabeth A.; Laditka, Sarah B.; Lowe, Anna E.

2013-01-01

Objective: To examine individual characteristics associated with local produce purchasing among North Carolina families with children. Design: Cross-sectional analysis using data from the 2008 North Carolina Child Health Assessment and Monitoring Program (NC CHAMP), a representative sample of adults who have land-line telephones. Setting: North…

Reconstruction de la surface de Fermi dans l'etat normal d'un supraconducteur a haute Tc: Une etude du transport electrique en champ magnetique intense

NASA Astrophysics Data System (ADS)

Le Boeuf, David

Des mesures de resistance longitudinale et de resistance de Hall en champ magnetique intense transverse (perpendiculaire aux plans CuO2) ont ete effectuees au sein de monocristaux de YBa2Cu3Oy (YBCO) demacles, ordonnes et de grande purete, afin d'etudier l'etat fondamental des supraconducteurs a haute Tc dans le regime sous-dope. Cette etude a ete realisee en fonction du dopage et de l'orientation du courant d'excitation J par rapport a l'axe orthorhombique b de la structure cristalline. Les mesures en champ magnetique intense revelent par suppression de la supraconductivite des oscillations magnetiques des resistances longitudinale et de Hall dans YBa2Cu 3O6.51 et YBa2Cu4O8. La conformite du comportement de ces oscillations quantiques au formalisme de Lifshitz-Kosevich, apporte la preuve de l'existence d'une surface de Fermi fermee a caractere quasi-2D, abritant des quasiparticules coherentes respectant la statistique de Fermi-Dirac, dans la phase pseudogap d'YBCO. La faible frequence des oscillations quantiques, combinee avec l'etude de la partie monotone de la resistance de Hall en fonction de la temperature indique que la surface de Fermi d'YBCO sous-dope comprend une petite poche de Fermi occupee par des porteurs de charge negative. Cette particularite de la surface de Fermi dans le regime sous-dope incompatible avec les calculs de structure de bande est en fort contraste avec la structure electronique presente dans le regime surdope. Cette observation implique ainsi l'existence d'un point critique quantique dans le diagramme de phase d'YBCO, au voisinage duquel la surface de Fermi doit subir une reconstruction induite par l'etablissement d'une brisure de la symetrie de translation du reseau cristallin sous-jacent. Enfin, l'etude en fonction du dopage de la resistance de Hall et de la resistance longitudinale en champ magnetique intense suggere qu'un ordre du type onde de densite (DW) est responsable de la reconstruction de la surface de Fermi. L'analogie de la phenomenologie entourant le comportement des resistances longitudinale et de Hall dans YBa2Cu3Oy, avec des systemes dans lesquels l'existence d'un ordre du type DW est etablie, notamment des cuprates a structure tetragonale a basse temperature ("Low Temperature Tetragonal", LTT), indique que l'ordre causant la reconstruction de la surface de Fermi est stabilise au voisinage du dopage p = 1/8, et est en competition directe avec la supraconductivite.

Development of an Atom Interferometer Gravity Gradiometer for Earth Sciences

NASA Technical Reports Server (NTRS)

Rakholia, A.; Sugarbaker, A.; Black, A.; Kasecivh, M.; Saif, B.; Luthcke, S.; Callahan, L.; Seery, B.; Feinberg, L.; Mather, J.;

Gravity Probe B

NASA Image and Video Library

2003-07-11

Workers in the spacecraft processing facility on North Vandenberg Air Force Base get ready to begin processing the Gravity Probe B experiment, including setting up mechanical and electrical ground support equipment, making necessary connections and conditioning the spacecraft battery. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

The Gravity of the Situation. Chapter 1

NASA Technical Reports Server (NTRS)

Paloski, William; Clement, Gilles; Bukley, Angie; Paloski, William

2006-01-01

Prolonged exposure in humans to a microgravity environment can lead to significant loss of bone and muscle mass, cardiovascular and sensory-motor deconditioning, and hormonal changes. These adaptive changes to weightlessness present a formidable obstacle to human exploration of space, particularly for missions requiring travel times of several months or more, such as on a trip to Mars. Countermeasures that address each of these body systems separately show only limited success. One possible remedy for this situation is artificial gravity, because it tackles all these systems across the board.

Testing Einstein in Space: The Gravity Probe B Relativity Mission

NASA Astrophysics Data System (ADS)

Mester, John

The Gravity Probe B Relativity Mission was successfully launched on April 20, 2004 from Vandenberg Air Force Base in California, a culmination of 40 years of collaborative development at Stanford University and NASA. The goal of the GP-B experiment is to perform precision tests of two independent predictions of general relativity, the geodetic effect and frame dragging. On-orbit cryogenic operations lasted 17.3 months, exceeding requirements. Analysis of the science data is now in progress with a planned announcement of results scheduled for December 2007.

Scattering and Propagation in Random Media

DTIC Science & Technology

1988-01-01

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78 FR 63211 - Privacy Act of 1974; Report of an Altered CMS System of Records Notice

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-23

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Medicare & Medicaid Services Privacy Act of... Services (CMS), Department of Health and Human Services (HHS). ACTION: Altered System of Records Notice...), Veterans Health Administration (Champ VA), Children's Health Insurance Program (CHIP), Department of...

Correlates of Externalizing Behavior Symptoms among Youth within Two Impoverished, Urban Communities

ERIC Educational Resources Information Center

Gopalan, Geetha; Cavaleri, Mary A.; Bannon, William M.; McKay, Mary M.

2009-01-01

This study examines whether risk factors associated with child externalizing behavior symptoms differ between two similar low-income, urban communities, using baseline parent data of 154 African American youth (ages 9-15) participating in the Collaborative HIV-Prevention and Adolescent Mental Health Project (CHAMP) family program. Separate…

Prior Learning Assessment Redesign: Using Evidence to Support Change

ERIC Educational Resources Information Center

McKay, Heather; Cohn, Bitsy; Kuang, Li

2016-01-01

In November 2014, the Colorado Community College System (CCCS) received a round three Trade Adjustment Assistance Community College Career Training (TAACCCT) grant from the United States Department of Labor. This grant, from the Colorado Helps Advanced Manufacturing Program (CHAMP), had two primary goals. The first was to facilitate the redesign…

75 FR 42446 - Ocean Transportation Intermediary License Applicants

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-21

... Change. CACC Global Logistics, Inc. (NVO & OFF), 151 E. 220th Street, Carson, CA 90754. Officers: Annie... NVO & OFF License. E-Freight Solutions Inc. dba E-Lines Shipping and Logistics, and Ocean Champ Shipping Limited (NVO), 1000 Corporate Center Drive, Suite 320, Monterey Park, CA 91754. Officers: Joey Tam...

Training Manual for HIV/AIDS Prevention.

ERIC Educational Resources Information Center

Epps, Patricia H.; Vallenari, Allison

This manual includes all necessary information for implementing the Champs program, which trains older elementary school students or middle/high school students to operate puppets to deliver an HIV/AIDS message to kindergarten through sixth graders. Relying on a peer approach, the Program provides scripted, prerecorded lessons intended to reach…

Fractional gravity studies on the ISS of sensory mechanisms involved in phototropism

NASA Astrophysics Data System (ADS)

Kiss, John Z.; Correll, Melanie; Edelmann, Richard; Millar, Katherine

The major goals of this research are (1) to better understand cellular mechanisms of pho-totropism in plants and (2) to determine the effects and influence of gravity on light perception in plants. Because of the interfering effect of the strong gravitropic response, microgravity conditions are needed to effectively study phototropism. Experiments performed on the In-ternational Space Station (ISS) were used to explore the mechanisms of both blue-light and red-light-induced phototropism in plants. We utilized the European Modular Cultivation Sys-tem (EMCS), which has environmental controls for plant growth as well as centrifuges for gravity treatments. TROPI-1 (for tropisms) was successfully performed on the ISS during late 2006. We obtained data on seedlings grown in microgravity and discovered a novel positive phototropic response to red light in hypocotyls of seedlings of Arabidopsis thaliana. However, one problem encoun-tered during TROPI-1 was low seed germination due to long storage periods (8 months) in flight hardware. Thus, the originally proposed fractional gravity studies were not performed. TROPI-2 provides an opportunity to regain the results from these important fractional gravity experiments. TROPI-2 experiments will provide a better understanding of how plants integrate sensory input from multiple light and gravity perception systems. This information is important for growing plants on long-term space missions as part of life support systems. The fractional gravity studies contain 0.16g (Moon) and 0.38g (Mars) treatments, so information to be obtained is relevant to exploration objectives

Evidence for a continuous spectrum of equatorial waves in the Indian Ocean

NASA Astrophysics Data System (ADS)

Eriksen, Charles C.

1980-06-01

Seven-month records of current and temperature measurements from a moored array centered at 53°E on the equator in the Indian Ocean are consistent with a continuous spectrum of equatorially trapped internal inertial-gravity, mixed Rossby-gravity, and Kelvin waves. A model spectrum of free linear waves analogous to those for mid-latitude internal gravity waves is used to compute spectra of observed quantities at depths greater than about 2000 m. Model parameters are adjusted to fit general patterns in the observed spectra over periods from roughly 2 days to 1 month. Measurements at shallower depths presumably include forced motions which we have not attempted to model. This `straw-person' spectrum is consistent with the limited data available. The model spectru Ē (n, m, ω) = K · B(m) · C(n, ω), where Ē is an average local energy density in the equatorial wave guide which has amplitude K, wave number shape B(m) ∝ (1 + m/m*)-3, where m is vertical mode number and the bandwidth parameter m* is between 4 and 8, and frequency shape C(n, ω) ∝ [(2n + 1 + s2)½ · σ3]-1 where n is meridional mode number, and s and σ are dimensionless zonal wave number and frequency related by the usual dispersion relation. The scales are (β/cm)½ and (β · cm)½ for horizontal wave number and frequency, where cm is the Kelvin wave speed of the vertical mode m. At each frequency and vertical wave number, energy is partitioned equally among the available inertial gravity modes so that the field tends toward horizontal isotropy at high frequency. The transition between Kelvin and mixed Rossby-gravity motion at low frequency and inertial-gravity motion at high frequency occurs at a period of roughly 1 week. At periods in the range 1-3 weeks, the model spectrum which fits the observations suggests that mixed Rossby-gravity motion dominates; at shorter periods gravity motion dominates. The model results are consistent with the low vertical coherence lengths observed (roughly 80 m). Horizontal coherence over 2 km is consistent with isotropic energy flux. Evidence for net zontal energy flux is not found in this data, and the presence of a red wave number shape suggests that net flux will be difficult to observe from modest moored arrays. The equatorial wave spectrum does not match across the diurnal and semidiurnal tides to the high-frequency internal wave spectrum (the latter is roughly 1 decade higher).

GOCE, Satellite Gravimetry and Antarctic Mass Transports

NASA Astrophysics Data System (ADS)

Rummel, Reiner; Horwath, Martin; Yi, Weiyong; Albertella, Alberta; Bosch, Wolfgang; Haagmans, Roger

2011-09-01

In 2009 the European Space Agency satellite mission GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) was launched. Its objectives are the precise and detailed determination of the Earth's gravity field and geoid. Its core instrument, a three axis gravitational gradiometer, measures the gravity gradient components V xx , V yy , V zz and V xz (second-order derivatives of the gravity potential V) with high precision and V xy , V yz with low precision, all in the instrument reference frame. The long wavelength gravity field is recovered from the orbit, measured by GPS (Global Positioning System). Characteristic elements of the mission are precise star tracking, a Sun-synchronous and very low (260 km) orbit, angular control by magnetic torquing and an extremely stiff and thermally stable instrument environment. GOCE is complementary to GRACE (Gravity Recovery and Climate Experiment), another satellite gravity mission, launched in 2002. While GRACE is designed to measure temporal gravity variations, albeit with limited spatial resolution, GOCE is aiming at maximum spatial resolution, at the expense of accuracy at large spatial scales. Thus, GOCE will not provide temporal variations but is tailored to the recovery of the fine scales of the stationary field. GRACE is very successful in delivering time series of large-scale mass changes of the Antarctic ice sheet, among other things. Currently, emphasis of respective GRACE analyses is on regional refinement and on changes of temporal trends. One of the challenges is the separation of ice mass changes from glacial isostatic adjustment. Already from a few months of GOCE data, detailed gravity gradients can be recovered. They are presented here for the area of Antarctica. As one application, GOCE gravity gradients are an important addition to the sparse gravity data of Antarctica. They will help studies of the crustal and lithospheric field. A second area of application is ocean circulation. The geoid surface from the gravity field model GOCO01S allows us now to generate rather detailed maps of the mean dynamic ocean topography and of geostrophic flow velocities in the region of the Antarctic Circumpolar Current.

The role of geomagnetic observatory data during the Swarm mission

NASA Astrophysics Data System (ADS)

Ridley, Victoria; Macmillan, Susan; Beggan, Ciaran

2014-05-01

The scientific use of Swarm magnetic data and Swarm-derived products is greatly enhanced through combination with observatory data and indices. The strength of observatory data is their long-term accuracy, with great care being taken to ensure temperature control and correction, platform stability and magnetic cleanliness at each site. Observatory data are being distributed with Swarm data as an auxiliary product. We describe the preparation of the data set of ground observatory hourly mean values, including procedures to check and select observatory data spanning the modern magnetic survey satellite era. Existing collaborations, such as INTERMAGNET and the World Data Centres for Geomagnetism, are proving invaluable for this. We also discuss how observatory measurements are being used to ground-truth Swarm data as part of the Calibration/Validation effort. Recent efforts to improve the coverage and timeliness of observatory data have been encouraged and now over 60 INTERMAGNET observatories and several other high-quality observatories are providing close-to-definitive data within 3 months of measurement. During the Calibration/Validation period these data are gathered and homogenised on a regular basis by BGS. We then identify measurements collected during overhead passes of the Swarm satellites. For each pass, we remove an estimate of the main field from both the data collected at altitude and that collected on the ground. Both sets of data are then normalised relative to the data variance during all passes in the Calibration/Validation period. The absolute differences of the two sets of normalised data can be used as a metric of satellite data quality relative to observatory data quality. This can be examined by universal time, local time, disturbance level and geomagnetic latitude, for example. A preliminary study of CHAMP data, using definitive minute mean observatory data, has shown how this approach can provide a baseline for detecting abnormalities at all local times and at different disturbance levels. Though it is difficult to predict how quasi-definitive data might affect the analysis, we present the results obtained for each Swarm satellite and compare these results with those found for CHAMP.

Ionospheric irregularities and acoustic/gravity wave activity above low-latitude thunderstorms

DOE PAGES

Lay, Erin H.

2017-12-18

Ionospheric irregularities due to plasma bubbles, scintillation, and acoustic/gravity waves are studied in the low-latitude ionosphere in relation to thunderstorm activity. Ionospheric total electron content (TEC) measurements from the Low Latitude Ionospheric Sensor Network (LISN) and lightning measurements from the World-Wide Lightning Location Network (WWLLN) are compared during two summer months and two winter months in 2013. Large amplitude fluctuations in TEC are found to have a strongly-peaked diurnal pattern in the late evening and nighttime summer ionosphere. The maximum magnitude and coverage area of these fluctuations increases as thunderstorm area increases. Summertime mid-amplitude fluctuations do not exhibit the samemore » diurnal variation, but do increase in magnitude and coverage area as thunderstorm area increases. Wintertime ionospheric fluctuations do not appear to be related to thunderstorm activity. Lastly, these findings show that thunderstorms have an observable effect on magnitude and coverage area of ionospheric fluctuations.« less

Ionospheric irregularities and acoustic/gravity wave activity above low-latitude thunderstorms

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

Lay, Erin H.

Ionospheric irregularities due to plasma bubbles, scintillation, and acoustic/gravity waves are studied in the low-latitude ionosphere in relation to thunderstorm activity. Ionospheric total electron content (TEC) measurements from the Low Latitude Ionospheric Sensor Network (LISN) and lightning measurements from the World-Wide Lightning Location Network (WWLLN) are compared during two summer months and two winter months in 2013. Large amplitude fluctuations in TEC are found to have a strongly-peaked diurnal pattern in the late evening and nighttime summer ionosphere. The maximum magnitude and coverage area of these fluctuations increases as thunderstorm area increases. Summertime mid-amplitude fluctuations do not exhibit the samemore » diurnal variation, but do increase in magnitude and coverage area as thunderstorm area increases. Wintertime ionospheric fluctuations do not appear to be related to thunderstorm activity. Lastly, these findings show that thunderstorms have an observable effect on magnitude and coverage area of ionospheric fluctuations.« less

Observed changes in the Earth's dynamic oblateness from GRACE data and geophysical models.

PubMed

Sun, Y; Ditmar, P; Riva, R

A new methodology is proposed to estimate changes in the Earth's dynamic oblateness ([Formula: see text] or equivalently, [Formula: see text]) on a monthly basis. The algorithm uses monthly Gravity Recovery and Climate Experiment (GRACE) gravity solutions, an ocean bottom pressure model and a glacial isostatic adjustment (GIA) model. The resulting time series agree remarkably well with a solution based on satellite laser ranging (SLR) data. Seasonal variations of the obtained time series show little sensitivity to the choice of GRACE solutions. Reducing signal leakage in coastal areas when dealing with GRACE data and accounting for self-attraction and loading effects when dealing with water redistribution in the ocean is crucial in achieving close agreement with the SLR-based solution in terms of de-trended solutions. The obtained trend estimates, on the other hand, may be less accurate due to their dependence on the GIA models, which still carry large uncertainties.

Ionospheric Irregularities and Acoustic/Gravity Wave Activity Above Low-Latitude Thunderstorms

NASA Astrophysics Data System (ADS)

Lay, Erin H.

2018-01-01

Ionospheric irregularities due to plasma bubbles, scintillation, and acoustic/gravity waves are studied in the low-latitude ionosphere in relation to thunderstorm activity. Ionospheric total electron content (TEC) measurements from the Low Latitude Ionospheric Sensor Network and lightning measurements from the World-Wide Lightning Location Network are compared during two summer months and two winter months in 2013. Large amplitude fluctuations in TEC are found to have a strongly peaked diurnal pattern in the late evening and nighttime summer ionosphere. The maximum magnitude and coverage area of these fluctuations increases as thunderstorm area increases. Summertime midamplitude fluctuations do not exhibit the same diurnal variation but do increase in magnitude and coverage area as thunderstorm area increases. Wintertime ionospheric fluctuations do not appear to be related to thunderstorm activity. These findings show that thunderstorms have an observable effect on magnitude and coverage area of ionospheric fluctuations.

Impact of tracking loop settings of the Swarm GPS receiver on gravity field recovery

NASA Astrophysics Data System (ADS)

Dahle, C.; Arnold, D.; Jäggi, A.

2017-06-01

The Swarm mission consists of three identical satellites equipped with GPS receivers and orbiting in near-polar low Earth orbits. Thus, they can be used to determine the Earth's gravity field by means of high-low satellite-to-satellite tracking (hl-SST). However, first results by several groups have revealed systematic errors both in precise science orbits and resulting gravity field solutions which are caused by ionospheric disturbances affecting the quality of Swarm GPS observations. Looking at gravity field solutions, the errors lead to systematic artefacts located in two bands north and south of the geomagnetic equator. In order to reduce these artefacts, erroneous GPS observations can be identified and rejected before orbit and gravity field processing, but this may also lead to slight degradations of orbit and low degree gravity field coefficient quality. Since the problems were believed to be receiver-specific, the GPS tracking loop bandwidths onboard Swarm have been widened several times starting in May 2015. The influence of these tracking loop updates on Swarm orbits and, particularly, gravity field solutions is investigated in this work. The main findings are that the first updates increasing the bandwidth from 0.25 Hz to 0.5 Hz help to significantly improve the quality of Swarm gravity fields and that the improvements are even larger than those achieved by GPS data rejection. It is also shown that these improvements are indeed due to an improved quality of GPS observations around the geomagnetic equator, and not due to missing observations in these regions. As the ionospheric activity is rather low in the most recent months, the effect of the tracking loop updates in summer 2016 cannot be properly assessed yet. Nevertheless, the quality of Swarm gravity field solutions has already improved after the first updates which is especially beneficial in view of filling the upcoming gap between the GRACE and GRACE Follow-on missions with hl-SST gravity products.

VANDENBERG AFB, CALIF. - The first stage of the Delta II launch vehicle for the Gravity Probe B experiment arrives at Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-15

VANDENBERG AFB, CALIF. - The first stage of the Delta II launch vehicle for the Gravity Probe B experiment arrives at Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - A worker in the spacecraft processing facility on North Vandenberg Air Force Base checks the Gravity Probe B experiment during prelaunch testing. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-12

VANDENBERG AFB, CALIF. - A worker in the spacecraft processing facility on North Vandenberg Air Force Base checks the Gravity Probe B experiment during prelaunch testing. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif., rolls back from the Delta II rocket that will launch the Gravity Probe B experiment. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-12

VANDENBERG AFB, CALIF. - The mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif., rolls back from the Delta II rocket that will launch the Gravity Probe B experiment. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

Further developments in orbit ephemeris derived neutral density

NASA Astrophysics Data System (ADS)

Locke, Travis

There are a number of non-conservative forces acting on a satellite in low Earth orbit. The one which is the most dominant and also contains the most uncertainty is atmospheric drag. Atmospheric drag is directly proportional to atmospheric density, and the existing atmospheric density models do not accurately model the variations in atmospheric density. In this research, precision orbit ephemerides (POE) are used as input measurements in an optimal orbit determination scheme in order to estimate corrections to existing atmospheric density models. These estimated corrections improve the estimates of the drag experienced by a satellite and therefore provide an improvement in orbit determination and prediction as well as a better overall understanding of the Earth's upper atmosphere. The optimal orbit determination scheme used in this work includes using POE data as measurements in a sequential filter/smoother process using the Orbit Determination Tool Kit (ODTK) software. The POE derived density estimates are validated by comparing them with the densities derived from accelerometers on board the Challenging Minisatellite Payload (CHAMP) and the Gravity Recovery and Climate Experiment (GRACE). These accelerometer derived density data sets for both CHAMP and GRACE are available from Sean Bruinsma of the Centre National d'Etudes Spatiales (CNES). The trend in the variation of atmospheric density is compared quantitatively by calculating the cross correlation (CC) between the POE derived density values and the accelerometer derived density values while the magnitudes of the two data sets are compared by calculating the root mean square (RMS) values between the two. There are certain high frequency density variations that are observed in the accelerometer derived density data but not in the POE derived density data or any of the baseline density models. These high frequency density variations are typically small in magnitude compared to the overall day-night variation. However during certain time periods, such as when the satellite is near the terminator, the variations are on the same order of magnitude as the diurnal variations. These variations can also be especially prevalent during geomagnetic storms and near the polar cusps. One of the goals of this work is to see what affect these unmodeled high frequency variations have on orbit propagation. In order to see this effect, the orbits of CHAMP and GRACE are propagated during certain time periods using different sources of density data as input measurements (accelerometer, POE, HASDM, and Jacchia 1971). The resulting orbit propagations are all compared to the propagation using the accelerometer derived density data which is used as truth. The RMS and the maximum difference between the different propagations are analyzed in order to see what effect the unmodeled density variations have on orbit propagation. These results are also binned by solar and geomagnetic activity level. The primary input into the orbit determination scheme used to produce the POE derived density estimates is a precision orbit ephemeris file. This file contains position and velocity in-formation for the satellite based on GPS and SLR measurements. The values contained in these files are estimated values and therefore contain some level of error, typically thought to be around the 5-10 cm level. The other primary focus of this work is to evaluate the effect of adding different levels of noise (0.1 m, 0.5 m, 1 m, 10 m, and 100 m) to this raw ephemeris data file before it is input into the orbit determination scheme. The resulting POE derived density estimates for each level of noise are then compared with the accelerometer derived densities by computing the CC and RMS values between the data sets. These results are also binned by solar and geomagnetic activity level.

Synoptic-scale variability of arctic gravity wave activity during summer and potential impacts on the high latitude middle atmosphere

NASA Astrophysics Data System (ADS)

Gerrard, Andrew John

Although the role of gravity waves in the global atmospheric circulation is generally understood, discussion of synoptic gravity wave activity, especially pertaining to high latitude summer environments, is lacking in the literature. Tropospherically generated gravity waves greatly contribute to the zonal drag necessary to induce meridional outflow and subsequent upwelling observed in the adiabatically cooled summer mesosphere, ultimately resulting in an environment conducive to mesospheric cloud formation. However, the very gravity wave activity responsible for this induced cooling is also believed to be a major source of variability on mesospheric clouds over shorter time scales, and this topic should be of considerable interest if such clouds are to be used as tracers of the global climate. It is therefore the purpose of this thesis to explore high latitude synoptic gravity wave activity and ultimately seek an understanding of the associated influence on overlaying summer mesospheric clouds. Another goal is to better understand and account for potential variability in high latitude middle and upper atmospheric measurements that can be directly associated with "weather conditions" at lower altitudes. These endeavors are addressed through Rayleigh/aerosol lidar data obtained from the ARCtic LIdar TEchnology (ARCLITE) facility located at Sondrestrom, Greenland (67°N, 310°E), global tropospheric and stratospheric analyses and forecasts, and the Gravity-wave Regional Or Global RAy Tracer (GROGRAT) model. In this study we are able to show that (a) the upper stratospheric gravity wave strength and the brightness of overlaying mesospheric clouds, as measured by representative field proxies, are negatively correlated over time scales of less than a day, (b) such upper stratospheric gravity wave variability is inversely related to mesospheric cloud variability on time scales of ˜1 to 4 hours, (c) gravity wave hindcasts faithfully reproduce experimental lidar observations taken over the month of August 1996, (d) the observed upper stratospheric gravity wave activity is shown to originate from regionalized, non-orographic sources in the troposphere, (e) such gravity wave activity can propagate through the middle atmosphere, potentially impacting overlaying mesospheric clouds, and (f) the forecasting of such upper stratospheric gravity wave activity, and therefore the corresponding mesospheric cloud activity, is feasible. In conclusion, the results herein provide additional evidence of gravity wave influence on mesospheric clouds, a step towards the forecasting of regional gravity wave activity, and ultimately a better understanding of synoptic gravity wave activity at high latitudes.

A space-time multiscale modelling of Earth's gravity field variations

NASA Astrophysics Data System (ADS)

Wang, Shuo; Panet, Isabelle; Ramillien, Guillaume; Guilloux, Frédéric

2017-04-01

The mass distribution within the Earth varies over a wide range of spatial and temporal scales, generating variations in the Earth's gravity field in space and time. These variations are monitored by satellites as the GRACE mission, with a 400 km spatial resolution and 10 days to 1 month temporal resolution. They are expressed in the form of gravity field models, often with a fixed spatial or temporal resolution. The analysis of these models allows us to study the mass transfers within the Earth system. Here, we have developed space-time multi-scale models of the gravity field, in order to optimize the estimation of gravity signals resulting from local processes at different spatial and temporal scales, and to adapt the time resolution of the model to its spatial resolution according to the satellites sampling. For that, we first build a 4D wavelet family combining spatial Poisson wavelets with temporal Haar wavelets. Then, we set-up a regularized inversion of inter-satellites gravity potential differences in a bayesian framework, to estimate the model parameters. To build the prior, we develop a spectral analysis, localized in time and space, of geophysical models of mass transport and associated gravity variations. Finally, we test our approach to the reconstruction of space-time variations of the gravity field due to hydrology. We first consider a global distribution of observations along the orbit, from a simplified synthetic hydrology signal comprising only annual variations at large spatial scales. Then, we consider a regional distribution of observations in Africa, and a larger number of spatial and temporal scales. We test the influence of an imperfect prior and discuss our results.

Design of Superconducting Gravity Gradiometer Cryogenic System for Mars Mission

NASA Technical Reports Server (NTRS)

Li, X.; Lemoine, F. G.; Paik, H. J.; Zagarola, M.; Shirron, P. J.; Griggs, C. E.; Moody, M. V.; Han, S.-C.

2016-01-01

Measurement of a planet's gravity field provides fundamental information about the planet's mass properties. The static gravity field reveals information about the internal structure of the planet, including crustal density variations that provide information on the planet's geological history and evolution. The time variations of gravity result from the movement of mass inside the planet, on the surface, and in the atmosphere. NASA is interested in a Superconducting Gravity Gradiometer (SGG) with which to measure the gravity field of a planet from orbit. An SGG instrument is under development with the NASA PICASSO program, which will be able to resolve the Mars static gravity field to degree 200 in spherical harmonics, and the time-varying field on a monthly basis to degree 20 from a 255 x 320 km orbit. The SGG has a precision two orders of magnitude better than the electrostatic gravity gradiometer that was used on the ESA's GOCE mission. The SGG operates at the superconducting temperature lower than 6 K. This study developed a cryogenic thermal system to maintain the SGG at the design temperature in Mars orbit. The system includes fixed radiation shields, a low thermal conductivity support structure and a two-stage cryocooler. The fixed radiation shields use double aluminized polyimide to emit heat from the warm spacecraft into the deep space. The support structure uses carbon fiber reinforced plastic, which has low thermal conductivity at cryogenic temperature and very high stress. The low vibration cryocooler has two stages, of which the high temperature stage operates at 65 K and the low temperature stage works at 6 K, and the heat rejection radiator works at 300 K. The study also designed a second option with a 4-K adiabatic demagnetization refrigerator (ADR) and two-stage 10-K turbo-Brayton cooler.

Design of Superconducting Gravity Gradiometer Cryogenic System for Mars Mission

NASA Technical Reports Server (NTRS)

Li, X.; Lemoine, F. G.; Shirron, P. J.; Paik, H. J.; Griggs, C. E.; Moody, M. V.; Han, S. C.; Zagarola, M.

2016-01-01

Measurement of a planets gravity field provides fundamental information about the planets mass properties. The static gravity field reveals information about the internal structure of the planet, including crustal density variations that provide information on the planets geological history and evolution. The time variations of gravity result from the movement of mass inside the planet, on the surface, and in the atmosphere. NASA is interested in a Superconducting Gravity Gradiometer (SGG) with which to measure the gravity field of a planet from orbit. An SGG instrument is under development with the NASA PICASSO program, which will be able to resolve the Mars static gravity field to degree 200 in spherical harmonics, and the time-varying field on a monthly basis to degree 20 from a 255 x 320 km orbit. The SGG has a precision two orders of magnitude better than the electrostatic gravity gradiometer that was used on the ESAs GOCE mission. The SGG operates at the superconducting temperature lower than 6 K. This study developed a cryogenic thermal system to maintain the SGG at the design temperature in Mars orbit. The system includes fixed radiation shields, a low thermal conductivity support structure and a two-stage cryocooler. The fixed radiation shields use double aluminized polyimide to emit heat from the warm spacecraft into the deep space. The support structure uses carbon fiber reinforced plastic, which has low thermal conductivity at cryogenic temperature and very high stress. The low vibration cryocooler has two stages, of which the high temperature stage operates at 65 K and the low temperature stage works at 6 K, and the heat rejection radiator works at 300 K. The study also designed a second option with a 4-K adiabatic demagnetization refrigerator (ADR) and two-stage 10-K turbo-Brayton cooler.

The Geopotential Research Mission - Mapping the near earth gravity and magnetic fields

NASA Technical Reports Server (NTRS)

Taylor, P. T.; Keating, T.; Smith, D. E.; Langel, R. A.; Schnetzler, C. C.; Kahn, W. D.

1983-01-01

The Geopotential Research Mission (GRM), NASA's low-level satellite system designed to measure the gravity and magnetic fields of the earth, and its objectives are described. The GRM will consist of two, Shuttle launched, satellite systems (300 km apart) that will operate simultaneously at a 160 km circular-polar orbit for six months. Current mission goals include mapping the global geoid to 10 cm, measuring gravity-field anomalies to 2 mgal with a spatial resolution of 100 km, detecting crustal magnetic anomalies of 100 km wavelength with 1 nT accuracy, measuring the vectors components to + or - 5 arc sec and 5 nT, and computing the main dipole or core field to 5 nT with a 2 nT/year secular variation detection. Resource analysis and exploration geology are additional applications considered.

Galileo 1989 VEEGA trajectory design. [Venus-Earth-Earth-Gravity-Assist

NASA Technical Reports Server (NTRS)

D'Amario, Louis A.; Byrnes, Dennis V.; Johannesen, Jennie R.; Nolan, Brian G.

1989-01-01

The new baseline for the Galileo Mission is a 1989 Venus-earth-earth gravity-assist (VEEGA) trajectory, which utilizes three gravity-assist planetary flybys in order to reduce launch energy requirements significantly compared to other earth-Jupiter transfer modes. The launch period occurs during October-November 1989. The total flight time is about 6 years, with November 1995 as the most likely choice for arrival at Jupiter. Optimal 1989 VEEGA trajectories have been generated for a wide range of earth launch dates and Jupiter arrival dates. Launch/arrival space contour plots are presented for various trajectory parameters, including propellant margin, which is used to measure mission performance. The accessible region of the launch/arrival space is defined by propellant margin and launch energy constraints; the available launch period is approximately 1.5 months long.

Gravity Probe B

NASA Image and Video Library

2003-07-13

In the spacecraft processing facility on North Vandenberg Air Force Base, workers prepare to remove the soft shipping cover from the Gravity Probe B experiment. Immediate processing includes setting up mechanical and electrical ground support equipment, making necessary connections and conditioning the spacecraft battery. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

Gravity Probe B

NASA Image and Video Library

2003-07-11

Workers in the spacecraft processing facility on North Vandenberg Air Force Base get ready to begin processing the Gravity Probe B experiment. Mechanical and electrical ground support equipment will be set up and necessary connections made with the spacecraft. Spacecraft battery conditioning will also begin. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

The Impact of CHAMPS on the Exclusionary Discipline Incidents of African-American Boys

ERIC Educational Resources Information Center

Russell-Smith, Saundra

2018-01-01

African-American boys who receive exclusionary discipline (i.e. in- or out-of-school suspensions) are overrepresented at the elementary (kindergarten through fifth grade) level. Although African-American boys comprised only 15% of the population of this school, they accounted for 70% of the exclusionary discipline incidents. This…

Thermospheric Data Assimilation

DTIC Science & Technology

2016-05-05

forecasting longer than 3 days. Furthermore, validation of assimilation analyses with independent CHAMP mass density observations confirms that the...approach developed in this project. 15. SUBJECT TERMS Data assimilation, Ensemble forecasting , Thermosphere-ionosphere coupled data assimilation...Neutral mass density specification and forecasting , 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 6 19a. NAME

Exploring Intercollegiate Athletic Department-Community Partnerships through the Lens of Community Service Organizations

ERIC Educational Resources Information Center

Svensson, Per G.; Huml, Matthew R.; Hancock, Meg G.

2014-01-01

Institutions of higher education are increasingly engaging in partnerships with local communities. Within a sport context, the creation of the NCAA CHAMPS/Life Skills Program has emphasized partnerships between athletic departments and local community service organizations (CSOs). Prior studies, however, have used student-athletes rather than the…

Competitions: What Parents of Gifted Students Must Know

ERIC Educational Resources Information Center

Karnes, Frances A.; Riley, Tracy L.

2005-01-01

The media calls them the wizards of tomorrow, the fix-it-kids, athletes of the mind, star players, and champs. These are the young people who compete and win academic, artistic, leadership, and service related competitions. Competitors spell words as difficult as autochthonous, make new scientific discoveries, compose poetry, publish their short…

Microscope in orbit calibration procedure for a test of the equivalence principle at 10(-15).

PubMed

Pradels, G; Touboul, P

2003-01-01

The scientific objectives of the MICROSCOPE space mission impose a very fine calibration of the on-board accelerometers. However the required performance cannot be achieved on ground because of the presence of high disturbing sources. On-board the CHAMP satellite, accelerometers similar in the concept to the MICROSCOPE instrument, have already flown and analysis of the provided data then allowed to characterise the vibration environment at low altitude as well as the fluctuation of the drag. The requirements of the in-orbit calibration procedure for the MICROSCOPE instrument are demonstrated by modelling the expected applied acceleration signals with the developed analytic model of the mission. The proposed approach exploits the drag-free system of the satellite and the sensitivity of the accelerometers. A specific simulator of the attitude control system of the satellite has been developed and tests of the proposed solution are performed using nominal conditions or disturbing conditions as observed during the CHAMP mission. c2003 International Astronautical Federation. Published by Elsevier Science Ldt. All rights reserved.

Utility of Satellite Magnetic Observations for Estimating Near-Surface Magnetic Anomalies

NASA Technical Reports Server (NTRS)

Kim, Hyung Rae; vonFrese, Ralph R. B.; Taylor, Patrick T.; Kim, Jeong Woo; Park, Chan Hong

2003-01-01

Regional to continental scale magnetic anomaly maps are becoming increasingly available from airborne, shipborne, and terrestrial surveys. Satellite data are commonly considered to fill the coverage gaps in regional compilations of these near-surface surveys. For the near-surface Antarctic magnetic anomaly map being produced by the Antarctic Digital Magnetic Anomaly Project (ADMAP), we show that near-surface magnetic anomaly estimation is greatly enhanced by the joint inversion of the near-surface data with the satellite observations relative to the conventional technique such as minimum curvature. Orsted observations are especially advantageous relative to the Magsat data that have order-of-magnitude greater measurement errors, albeit at much lower orbital altitudes. CHAMP is observing the geomagnetic field with the same measurement accuracy as the Orsted mission, but at the lower orbital altitudes covered by Magsat. Hence, additional significant improvement in predicting near-surface magnetic anomalies can result as these CHAMP data are available. Our analysis also suggests that considerable new insights on the magnetic properties of the lithosphere may be revealed by a further order-of-magnitude improvement in the accuracy of the magnetometer measurements at minimum orbital altitude.

Modélisation par éléments finis 3D du champ magnétostatique dans les enroulements des réactances cuirassées de grande puissance. Comparaison avec le calcul en 2D

NASA Astrophysics Data System (ADS)

Ngnegueu, Triomphant; Terme, Claude; Mailhot, Michel

1993-03-01

In this paper, the finite element method is applied for the computation of the magnetostatic field in the windings of a shell-form reactor. The modeling is carried out in 3D, using FLUX3D, a software developed at the Laboratoire d'Electrotechnique de Grenoble. The results are compared to those obtained in 2D. These calculation results are also compared to some test results. Dans cet article, nous décrivons une application de la méthode des éléments finis pour la modélisation du champ magnétostatique dans les enroulements d'une réactance cuirassée de grande puissance. La modélisation est conduite en 3D, en utilisant le logiciel FLUX3D. Les résultats du calcul sont comparés avec ceux obtenus en 2D. Quelques comparaisons sont aussi effectuées avec des résultats de mesure.

Thermospheric density variations: Observability using precision satellite orbits and effects on orbit propagation

NASA Astrophysics Data System (ADS)

Lechtenberg, Travis; McLaughlin, Craig A.; Locke, Travis; Krishna, Dhaval Mysore

2013-01-01

paper examines atmospheric density estimated using precision orbit ephemerides (POE) from the CHAMP and GRACE satellites during short periods of greater atmospheric density variability. The results of the calibration of CHAMP densities derived using POEs with those derived using accelerometers are examined for three different types of density perturbations, [traveling atmospheric disturbances (TADs), geomagnetic cusp phenomena, and midnight density maxima] in order to determine the temporal resolution of POE solutions. In addition, the densities are compared to High-Accuracy Satellite Drag Model (HASDM) densities to compare temporal resolution for both types of corrections. The resolution for these models of thermospheric density was found to be inadequate to sufficiently characterize the short-term density variations examined here. Also examined in this paper is the effect of differing density estimation schemes by propagating an initial orbit state forward in time and examining induced errors. The propagated POE-derived densities incurred errors of a smaller magnitude than the empirical models and errors on the same scale or better than those incurred using the HASDM model.

CHAMP: a locally adaptive unmixing-based hyperspectral anomaly detection algorithm

NASA Astrophysics Data System (ADS)

Crist, Eric P.; Thelen, Brian J.; Carrara, David A.

1998-10-01

Anomaly detection offers a means by which to identify potentially important objects in a scene without prior knowledge of their spectral signatures. As such, this approach is less sensitive to variations in target class composition, atmospheric and illumination conditions, and sensor gain settings than would be a spectral matched filter or similar algorithm. The best existing anomaly detectors generally fall into one of two categories: those based on local Gaussian statistics, and those based on linear mixing moles. Unmixing-based approaches better represent the real distribution of data in a scene, but are typically derived and applied on a global or scene-wide basis. Locally adaptive approaches allow detection of more subtle anomalies by accommodating the spatial non-homogeneity of background classes in a typical scene, but provide a poorer representation of the true underlying background distribution. The CHAMP algorithm combines the best attributes of both approaches, applying a linear-mixing model approach in a spatially adaptive manner. The algorithm itself, and teste results on simulated and actual hyperspectral image data, are presented in this paper.

Properties of traveling atmospheric disturbances (TADs) inferred from CHAMP accelerometer observations

NASA Astrophysics Data System (ADS)

Bruinsma, Sean L.; Forbes, Jeffrey M.

2009-02-01

Densities derived from accelerometer measurements on the CHAMP satellite near 400 km are used to statistically establish characteristics of large-scale (>1000 km) traveling atmospheric disturbances (TADs). Only TADs that at least propagate from the auroral zone to the equator are analyzed here, and a total of 21 identifiable events are found over the years 2001 2007. The average speed of all TADs, regardless of local time, is 646 ± 122 ms-1. The average speeds on the dayside and nightside are 595 ± 127 ms-1 and 685 ± 106 ms-1, respectively, i.e., the speed appears to be 10% higher on average on the nightside. On six occasions TADs were only detected on the night side; however, TADs on the dayside often appear more distinctly in the data. Moreover, contrary to some theoretical expectations, dayside TADs do not dissipate more readily than night side TADs, although much less are detected between 8 20 solar local time. No clear dependence of TAD amplitude or phase speed with respect to Kp, or rate of increase of Kp, is found.

Substorm-related thermospheric density and wind disturbances derived from CHAMP observations

NASA Astrophysics Data System (ADS)

Ritter, P.; Lühr, H.; Doornbos, E.

2010-06-01

The input of energy and momentum from the magnetosphere is most efficiently coupled into the high latitude ionosphere-thermosphere. The phenomenon we are focusing on here is the magnetospheric substorm. This paper presents substorm related observations of the thermosphere derived from the CHAMP satellite. With its sensitive accelerometer the satellite can measure the air density and zonal winds. Based on a large number of substorm events the average high and low latitude thermospheric response to substorm onsets was deduced. During magnetic substorms the thermospheric density is enhanced first at high latitudes. Then the disturbance travels at an average speed of 650 m/s to lower latitudes, and 3-4 h later the bulge reaches the equator on the night side. Under the influence of the Coriolis force the travelling atmospheric disturbance (TAD) is deflected westward. In accordance with present-day atmospheric models the disturbance zonal wind velocities during substorms are close to zero near the equator before midnight and attain moderate westward velocities after midnight. In general, the wind system is only weakly perturbed (Δvy<20 m/s) by substorms.

Etude de pratiques d'enseignement relatives a la modelisation en sciences et technologies avec des enseignants du secondaire

NASA Astrophysics Data System (ADS)

Aurousseau, Emmanuelle

Les modeles sont des outils amplement utilises en sciences et technologies (S&T) afin de representer et d’expliquer un phenomene difficilement accessible, voire abstrait. La demarche de modelisation est presentee de maniere explicite dans le programme de formation de l’ecole quebecoise (PFEQ), notamment au 2eme cycle du secondaire (Quebec. Ministere de l'Education du Loisir et du Sport, 2007a). Elle fait ainsi partie des sept demarches auxquelles eleves et enseignants sont censes recourir. Cependant, de nombreuses recherches mettent en avant la difficulte des enseignants a structurer leurs pratiques d’enseignement autour des modeles et de la demarche de modelisation qui sont pourtant reconnus comme indispensables. En effet, les modeles favorisent la conciliation des champs concrets et abstraits entre lesquels le scientifique, meme en herbe, effectue des allers-retours afin de concilier le champ experimental de reference qu’il manipule et observe au champ theorique relie qu’il construit. L’objectif de cette recherche est donc de comprendre comment les modeles et la demarche de modelisation contribuent a faciliter l’articulation du concret et de l’abstrait dans l’enseignement des sciences et des technologies (S&T) au 2eme cycle du secondaire. Pour repondre a cette question, nous avons travaille avec les enseignants dans une perspective collaborative lors de groupes focalises et d’observation en classe. Ces dispositifs ont permis d’examiner les pratiques d’enseignement que quatre enseignants mettent en oeuvre en utilisant des modeles et des demarches de modelisation. L’analyse des pratiques d’enseignement et des ajustements que les enseignants envisagent dans leur pratique nous permet de degager des connaissances a la fois pour la recherche et pour la pratique des enseignants, au regard de l’utilisation des modeles et de la demarche de modelisation en S&T au secondaire.

VizieR Online Data Catalog: Galactic CHaMP. II. Dense gas clumps. (Ma+, 2013)

NASA Astrophysics Data System (ADS)

Ma, B.; Tan, J. C.; Barnes, P. J.

2015-04-01

A total of 303 dense gas clumps have been detected using the HCO+(1-0) line in the CHaMP survey (Paper I, Barnes et al. 2011, J/ApJS/196/12). In this article we have derived the SED for these clumps using Spitzer, MSX, and IRAS data. The Midcourse Space Experiment (MSX) was launched in 1996 April. It conducted a Galactic plane survey (0

Élimination du bore du silicium par plasma inductif sous champ électrique

NASA Astrophysics Data System (ADS)

Combes, R.; Morvan, D.; Picard, G.; Amouroux, J.

1993-05-01

We analyzed purification mechanisms of silicon by inductive plasma with a fluoride slag. The aim is to study boron elimination from doped electronic grade silicon in function of the nature of the slag to obtain a photovoltaic grade silicon. The steady began with the calculation and the comparison of the stability diagram of boron compounds in presence of CaF2, BaF2 and MgF2. This study led us to conclude that BaF2 is the better slag for silicon purification. This has been confirmed by experience. In a second time, we made purifications under electric bias to enhance slag efficiency. We noticed that BaF2 is more sensitive to electric bias than other slags. Nous avons analysé le mécanisme de purification du silicium sous plasma inductif en présence d'un laitier fluoré. L'objectif principal est d'étudier l'élimination du bore du silicium électronique dopé en fonction de la nature du fluorure pour obtenir un silicium de qualité photovoltaïque. L'étude a commencé par l'établissement et la comparaison de diagrammes des composés du bore en présence de CaF2, de MgF2 et de BaF2. Nous avons déduit de cette première étude que BaF2 est le meilleur laitier pour la purification du silicium. Ceci a été corroboré par l'expérience. Nous avons ensuite opéré en présence d'un champ électrique dans le but d'améliorer encore l'efficacité des laitiers. Nous avons constaté que BaF2 est plus sensible au champ électrique que les deux autres laitiers utilisés.

Mineral resource of the month: barite

USGS Publications Warehouse

Miller, M. Michael

2006-01-01

Also called barytes, barite forms in various geologic environments and is frequently found with both metallic and nonmetallic minerals. Most barite is produced by open-pit mining techniques, and most crude barite requires some upgrading to meet minimum purity or specific gravity levels.

Co-Seismic Gravity Gradient Changes of the 2006-2007 Great Earthquakes in the Central Kuril Islands from GRACE Observations

NASA Astrophysics Data System (ADS)

Rahimi, A.; Shahrisvand, M.

2017-09-01

GRACE satellites (the Gravity Recovery And climate Experiment) are very useful sensors to extract gravity anomalies after earthquakes. In this study, we reveal co-seismic signals of the two combined earthquakes, the 2006 Mw8.3 thrust and 2007 Mw8.1 normal fault earthquakes of the central Kuril Islands from GRACE observations. We compute monthly full gravitational gradient tensor in the local north-east-down frame for Kuril Islands earthquakes without spatial averaging and de-striping filters. Some of gravitational gradient components (e.g. ΔVxx, ΔVxz) enhance high frequency components of the earth gravity field and reveal more details in spatial and temporal domain. Therefore, co-seismic activity can be better illustrated. For the first time, we show that the positive-negative-positive co-seismic ΔVxx due to the Kuril Islands earthquakes ranges from - 0.13 to + 0.11 milli Eötvös, and ΔVxz shows a positive-negative-positive pattern ranges from - 0.16 to + 0.13 milli Eötvös, agree well with seismic model predictions.

Source Parameter Inversion for Recent Great Earthquakes from a Decade-long Observation of Global Gravity Fields

NASA Technical Reports Server (NTRS)

Han, Shin-Chan; Riva, Ricccardo; Sauber, Jeanne; Okal, Emile

2013-01-01

We quantify gravity changes after great earthquakes present within the 10 year long time series of monthly Gravity Recovery and Climate Experiment (GRACE) gravity fields. Using spherical harmonic normal-mode formulation, the respective source parameters of moment tensor and double-couple were estimated. For the 2004 Sumatra-Andaman earthquake, the gravity data indicate a composite moment of 1.2x10(exp 23)Nm with a dip of 10deg, in agreement with the estimate obtained at ultralong seismic periods. For the 2010 Maule earthquake, the GRACE solutions range from 2.0 to 2.7x10(exp 22)Nm for dips of 12deg-24deg and centroid depths within the lower crust. For the 2011 Tohoku-Oki earthquake, the estimated scalar moments range from 4.1 to 6.1x10(exp 22)Nm, with dips of 9deg-19deg and centroid depths within the lower crust. For the 2012 Indian Ocean strike-slip earthquakes, the gravity data delineate a composite moment of 1.9x10(exp 22)Nm regardless of the centroid depth, comparing favorably with the total moment of the main ruptures and aftershocks. The smallest event we successfully analyzed with GRACE was the 2007 Bengkulu earthquake with M(sub 0) approx. 5.0x10(exp 21)Nm. We found that the gravity data constrain the focal mechanism with the centroid only within the upper and lower crustal layers for thrust events. Deeper sources (i.e., in the upper mantle) could not reproduce the gravity observation as the larger rigidity and bulk modulus at mantle depths inhibit the interior from changing its volume, thus reducing the negative gravity component. Focal mechanisms and seismic moments obtained in this study represent the behavior of the sources on temporal and spatial scales exceeding the seismic and geodetic spectrum.

The impact of (mega)-cities on the earth's gravity

NASA Astrophysics Data System (ADS)

Schnitzer, S.; Estrella, N.; Güntner, A.; Matiu, M.; Peterseim, N.; Menzel, A.

2013-12-01

The world population is constantly growing; today over 7 billion people populate the planet. This development has led to a strong urbanization and expanding cities. According to the United Nations, since 2007 more human beings have lived in urban areas than in rural areas, and by 2030 the urban share will be more than 60%. The challenges of fast growing cities lie in urban management, supply to inhabitants of resources (e.g. water, power, food), and strong environmental problems (e.g. pollution), i.e. their ecological footprint. In our study we address the question of another footprint, whether (mega)-cities have an impact on the earth's gravity field. Analyzing the possible triggers will help to understand the multiple footprints of big cities in various regions. We analyze several data sources. The main data sets are a) monthly solutions of the gravity satellite mission GRACE, detecting changes in the earth's gravity field over time, b) data of the hydrological model WGHM, estimating mass changes in terrestrial and ground water storage, c) urban population data of the United Nations, d) land cover information of the European Space Agency, e) different climate data sets and other auxiliary data. The results suggest a non-uniform pattern of gravity changes with variations in trends related to different clustering parameters.

Thermosphere Global Time Response to Geomagnetic Storms Caused by Coronal Mass Ejections

NASA Astrophysics Data System (ADS)

Oliveira, D. M.; Zesta, E.; Schuck, P. W.; Sutton, E. K.

2017-10-01

We investigate, for the first time with a spatial superposed epoch analysis study, the thermosphere global time response to 159 geomagnetic storms caused by coronal mass ejections (CMEs) observed in the solar wind at Earth's orbit during the period of September 2001 to September 2011. The thermosphere neutral mass density is obtained from the CHAMP (CHAllenge Mini-Satellite Payload) and GRACE (Gravity Recovery Climate Experiment) spacecraft. All density measurements are intercalibrated against densities computed by the Jacchia-Bowman 2008 empirical model under the regime of very low geomagnetic activity. We explore both the effects of the pre-CME shock impact on the thermosphere and of the storm main phase onset by taking their times of occurrence as zero epoch times (CME impact and interplanetary magnetic field Bz southward turning) for each storm. We find that the shock impact produces quick and transient responses at the two high-latitude regions with minimal propagation toward lower latitudes. In both cases, thermosphere is heated in very high latitude regions within several minutes. The Bz southward turning of the storm onset has a fast heating manifestation at the two high-latitude regions, and it takes approximately 3 h for that heating to propagate down to equatorial latitudes and to globalize in the thermosphere. This heating propagation is presumably accomplished, at least in part, with traveling atmospheric disturbances and complex meridional wind structures. Current models use longer lag times in computing thermosphere density dynamics during storms. Our results suggest that the thermosphere response time scales are shorter and should be accordingly adjusted in thermospheric empirical models.

Application of the satellite system of the earth's gravity field measurement (GRACE) for the evaluation of water balance in large Russian river catchments

NASA Astrophysics Data System (ADS)

Frolova, Natalia; Zotov, Leonid; Grigoriev, Vadim; Sazonov, Alexey; Kireeva, Maria; Krylenko, Inna

2017-04-01

Space-based Earth observing systems provided a substantially large amount of information to the scientific community in recent decades. Cumulative effects of redistribution of masses in the Earth system can be seen in the changes of the gravity field of the Earth. Gravity Recovery and Climate Experiment (GRACE) satellites, launched 17.03.2002 from Plesetsk, provide a set of monthly Earth's gravity field observations. GRACE data is very useful for hydrological and climatological studies, especially over large territory, not completely covered by the meteorological and hydrological networks, like Russia. Possible application of the satellite gravity survey data obtained under the GRACE for solving various hydrological problems is discussed. The GRACE-based monthly gravity field data are transformed into the maps of water level equivalent and averaged for the catchments of the largest rivers of Russia. The temporal variability of the parameter is analyzed. Possible application of the GRACE data for the evaluation of particular components of water balance within the largest river basins of the European part of Russia is discussed. After averaging over 15 large Russian rivers basins annual component shows amplitude increase since 2009. Trend component grows until 2009 and then reaches a plateau. It is mostly dominated by Siberian rivers. Map for the trend show gravity field increase in Siberia, at Back Sea and decrease over Caspian Sea since 2003. GRACE satellite gravimetry data can be used for estimating terrestrial water storage (TWS) in a river basin scale. Terrestrial water storage (TWS) is the integrated sum of all basin storages (surface water bodies, soil and ground aquifer, snowpack and glaciers) and the ability to estimate TWS dynamics is useful for understanding the basin's water cycle, its interconnection with the local climate, physics of predictability of extreme hydrological events. Despite the importance of the TWS estimates, reliable ground-based monitoring data of all TWS components are scarce or absent at all. Since observations are not sufficient to monitor TWS, hydrological models are considered as a comprehensive tool to simulate TWS components at a basin scale. However accuracy of the model-derived TWS is influenced by the uncertainty of the model structure and parameters, reliability of input data, etc. To improve the TWS-estimates, it is reasonable to combine the simulated TWS with independent observations provided by the GRACE gravity data. Ninety-seven monthly TWS retrieval from GRACE data (from April 2002 to December 2009) was examined and compared with TWS-estimates obtained by the ECOMAG hydrological model simulations. The case study was carried out for the Northern Dvina River basin. Quantitative analyze between the hydrological model and GRACE-based TWS showed that latter is in good consistency with the simulation results on both seasonal and inter-annual time scales. Overall, the results highlight the benefit of assimilating GRACE data for hydrological applications, particularly in data-sparse regions, while also providing insight on future refinements of the methodology of GRACE-data application in watershed hydrology. The study is financially supported by the Russian Foundation for Basic Research (Proj.№ 16-35-60080; 16-05-00753) and the Russian Science Foundation (Grant No. 14-17-00155).

Towards combined global monthly gravity field solutions

NASA Astrophysics Data System (ADS)

Jaeggi, Adrian; Meyer, Ulrich; Beutler, Gerhard; Weigelt, Matthias; van Dam, Tonie; Mayer-Gürr, Torsten; Flury, Jakob; Flechtner, Frank; Dahle, Christoph; Lemoine, Jean-Michel; Bruinsma, Sean

2014-05-01

Currently, official GRACE Science Data System (SDS) monthly gravity field solutions are generated independently by the Centre for Space Research (CSR) and the German Research Centre for Geosciences (GFZ). Additional GRACE SDS monthly fields are provided by the Jet Propulsion Laboratory (JPL) for validation and outside the SDS by a number of other institutions worldwide. Although the adopted background models and processing standards have been harmonized more and more by the various processing centers during the past years, notable differences still exist and the users are more or less left alone with a decision which model to choose for their individual applications. This procedure seriously limits the accessibility of these valuable data. Combinations are well established in the area of other space geodetic techniques, such as the Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR), and Very Long Baseline Interferometry (VLBI). Regularly comparing and combining space-geodetic products has tremendously increased the usefulness of the products in a wide range of disciplines and scientific applications. Therefore, we propose in a first step to mutually compare the large variety of available monthly GRACE gravity field solutions, e.g., by assessing the signal content over selected regions, by estimating the noise over the oceans, and by performing significance tests. We make the attempt to assign different solution characteristics to different processing strategies in order to identify subsets of solutions, which are based on similar processing strategies. Using these subsets we will in a second step explore ways to generate combined solutions, e.g., based on a weighted average of the individual solutions using empirical weights derived from pair-wise comparisons. We will also assess the quality of such a combined solution and discuss the potential benefits for the GRACE and GRACE-FO user community, but also address minimum processing requirements to be met by each analysis centre to enable a meaningful combination (either performed on the solution level or, preferably, on the normal equation level).

Location and severity of spasticity in the first 1-2 weeks and at 3 and 18 months after stroke.

PubMed

Welmer, A-K; Widén Holmqvist, L; Sommerfeld, D K

2010-05-01

There is no consensus concerning the location or severity of spasticity, or how this changes with time after stroke. The purpose was to describe: the location and severity of spasticity, in different muscle groups, during the first 1-2 weeks and at 3 and 18 months after stroke; the association between the severity of spasticity and control of voluntary movements; and the occurrence of spasticity in younger versus older patients. In a cohort of consecutive patients, the following parameters were assessed during the first 1-2 weeks (n = 109) and at 3 (n = 95) and 18 (n = 66) months after first-ever stroke: spasticity, by the Modified Ashworth Scale in different muscle groups; plantar-flexor clonus, by physical examination; and movement function, by the Lindmark Motor Assessment Scale. During the first 1-2 weeks and at 3 months after stroke, spasticity was most common in the anti-gravity muscles. The severity of upper extremity spasticity increased over time (P < 0.05). Upper extremity spasticity and movement scores were moderately associated (r = -0.61, P < 0.05). At 3 months, spasticity was more common amongst the younger patients (P < 0.05). The results confirm that spasticity is most common in the anti-gravity muscles and is associated with the control of voluntary movements. As the severity of spasticity also increased after 3 months, when neurally mediated spasticity is expected to have passed its peak, intrinsic muscle changes may play a larger role than neural components with the passage of time after stroke.

Editorial:

NASA Astrophysics Data System (ADS)

Wald, Robert M.

2004-01-01

I am very pleased to be assuming the Editorship of Classical and Quantum Gravity for the next five years. I hope to continue the successful policies that have made this journal well known for its openness to new developments in the field, for the efficiency of its editorial process, and for the quality and importance of its articles. Classical and Quantum Gravity has truly blossomed under the guidance of its previous Editors-in-Chief, Malcolm MacCallum, Kellogg Stelle, Gary Gibbons and Hermann Nicolai. During the past 12 months, a total of 847 manuscripts have been submitted, representing an increase of nearly 50% over the past four years alone. Beginning in 2000, the frequency of publication was increased from 12 to 24 issues per year. The rate of full-text downloads is now 7200 per month, nearly a three-fold increase over four years. For regular manuscripts, the average time between receipt and first decision now stands at only 59 days, the receipt-to-acceptance time is now only 72 days, and the receipt-to-online publication time is only 116 days. The corresponding times for letters are 36 days, 44 days and 62 days, respectively. Much of the improvement in refereeing and publication times can be directly attributed to the state-of-the art Web-based refereeing system, maintained by the able administration of the IOP editorial team, consisting of Andrew Wray, Joe Tennant, Joanne Rowse and Susannah Bruce. Both the growth in journal size and the decrease in publication times have been accomplished without any decrease in quality. As one objective measure of this, the 'impact factor' index of Classical and Quantum Gravity has risen steadily over the past four years. Even more significantly, Classical and Quantum Gravity has undergone major intellectual growth since its founding. In 1984, modern string theory was in the process of being born, the subject of 'loop quantum gravity' did not exist at all, 'new inflation' truly was 'new', and the possibility of observing gravitational radiation by laser interferometry was not much more than a dream. Similarly, neither the power of modern desktop computers nor the wealth of present cosmological data was widely anticipated. The subjects of 'classical and quantum gravity' were very different in 1984 from what they are in 2004, but the journal Classical and Quantum Gravity has kept up with the changes and developments (and, in some cases, revolutions) that have occurred in these areas. Much of this openness towards new developments in the field can be attributed to the distinguished Editorial Board of Classical and Quantum Gravity, comprising a very broad mix of leading researchers, many of whom are working at the cutting edge of research in their sub-fields. My goal during the next five years is to maintain the open and forward-looking approach that has been characteristic of Classical and Quantum Gravity, while at the same time ensuring that the highest intellectual standards are applied to all work published by the journal.

An overview of the Columbia Habitat Monitoring Program's (CHaMP) spatial-temporal design framework

EPA Science Inventory

We briefly review the concept of a master sample applied to stream networks in which a randomized set of stream sites is selected across a broad region to serve as a list of sites from which a subset of sites is selected to achieve multiple objectives of specific designs. The Col...

Ionospheric Behavior During the First Few Hours of Intense Geomagnetic Storms

NASA Technical Reports Server (NTRS)

Mannucci, Anthony J.; Crowley, Geoff; Tsurutani, Bruce; Fuller-Rowell, Tim

2006-01-01

The behavior of the ionosphere during the first few hours of intense geomagnetic storms is presented. The topics include: 1) TEC Modification; 2) JASON TEC (1336 km altitude); 3) Multiple Storms; 4) CHAMP (greater than 400 km) November 20, 2003; 5) November 20, 1PM LT, Ground; 6) Role of Modeling; and 7) Composition-related increase.

Self-Esteem Enhancing Reasons for Having Sex and the Sexual Behaviors of African American Adolescents

ERIC Educational Resources Information Center

Robinson, Melissa L.; Holmbeck, Grayson N.; Paikoff, Roberta

2007-01-01

A sample of 146 African American adolescents living in impoverished neighborhoods with high HIV rates participated in the Chicago HIV Prevention and Adolescent Mental Health Project (CHAMP), a longitudinal study of adolescent HIV risk exposure. The current study examined self-reported reasons why African American adolescents may participate in…

ARC-2009-ACD09-0150-002

NASA Image and Video Library

2009-07-22

NASA Research Park (NRP) Moffett Field, California: Timothy Collins, President and Chairman, KleenSpeed Technologies, Inc. and Captain Andrew Butte, rescue helicopter pilot and former Army Aviator, with Butte's 1999 SWIFT. ChampCar Butte has given his racecar to KleenSpeed for conversion to electric. KleenSpeed is an advanced R&D firm focusing on scalable electric propulsion systems for transportation.

Large scale mass redistribution and surface displacement from GRACE and SLR

NASA Astrophysics Data System (ADS)

Cheng, M.; Ries, J. C.; Tapley, B. D.

2012-12-01

Mass transport between the atmosphere, ocean and solid earth results in the temporal variations in the Earth gravity field and loading induced deformation of the Earth. Recent space-borne observations, such as GRACE mission, are providing extremely high precision temporal variations of gravity field. The results from 10-yr GRACE data has shown a significant annual variations of large scale vertical and horizontal displacements occurring over the Amazon, Himalayan region and South Asia, African, and Russian with a few mm amplitude. Improving understanding from monitoring and modeling of the large scale mass redistribution and the Earth's response are a critical for all studies in the geosciences, in particular for determination of Terrestrial Reference System (TRS), including geocenter motion. This paper will report results for the observed seasonal variations in the 3-dimentional surface displacements of SLR and GPS tracking stations and compare with the prediction from time series of GRACE monthly gravity solution.

Development of gravity-sensing organs in altered gravity

NASA Technical Reports Server (NTRS)

Wiederhold, M. L.; Gao, W. Y.; Harrison, J. L.; Hejl, R.

1997-01-01

Experiments are described in which the development of the gravity-sensing organs was studied in newt larvae reared in microgravity on the IML-2 mission and in Aplysia embryos and larvae reared on a centrifuge at 1 to 5 g. In Aplysia embryos, the statolith (single dense mass on which gravity and linear acceleration act) was reduced in size in a graded fashion at increasing g. In early post-metamorphic Aplysia or even in isolated statocysts from such animals, the number of statoconia produced is reduced at high g. Newt larvae launched before any of the otoconia were formed and reared for 15 days in microgravity had nearly adult labyrinths at the end of the IML-2 mission. The otoliths of the saccule and utricle were the same size in flight and ground-reared larvae. However, the system of aragonitic otoconia produced in the endolymphatic sac in amphibians was much larger and developed earlier in the flight-reared larvae. At later developmental stages, the aragonitic otoconia enter and fill the saccule. One flight-reared larva was maintained for nine months post-flight and the size of the saccular otolith, as well as the volume of otoconia within the endolymphatic sac, were considerably larger than in age-matched, ground-reared newts. This suggests that rearing in microgravity initiates a process that continues for several months after introduction to 1-g, which greatly increases the volume of otoconia. The flight-reared animal had abnormal posture, pointing its head upward, whereas normal ground-reared newts always keep their head horizontal. This suggests that rearing for even a short period in microgravity can have lasting functional consequences in an animal subsequently reared in 1-g conditions on Earth.

An improved GRACE monthly gravity field solution by modeling the non-conservative acceleration and attitude observation errors

NASA Astrophysics Data System (ADS)

Chen, Qiujie; Shen, Yunzhong; Chen, Wu; Zhang, Xingfu; Hsu, Houze

2016-06-01

The main contribution of this study is to improve the GRACE gravity field solution by taking errors of non-conservative acceleration and attitude observations into account. Unlike previous studies, the errors of the attitude and non-conservative acceleration data, and gravity field parameters, as well as accelerometer biases are estimated by means of weighted least squares adjustment. Then we compute a new time series of monthly gravity field models complete to degree and order 60 covering the period Jan. 2003 to Dec. 2012 from the twin GRACE satellites' data. The derived GRACE solution (called Tongji-GRACE02) is compared in terms of geoid degree variances and temporal mass changes with the other GRACE solutions, namely CSR RL05, GFZ RL05a, and JPL RL05. The results show that (1) the global mass signals of Tongji-GRACE02 are generally consistent with those of CSR RL05, GFZ RL05a, and JPL RL05; (2) compared to CSR RL05, the noise of Tongji-GRACE02 is reduced by about 21 % over ocean when only using 300 km Gaussian smoothing, and 60 % or more over deserts (Australia, Kalahari, Karakum and Thar) without using Gaussian smoothing and decorrelation filtering; and (3) for all examples, the noise reductions are more significant than signal reductions, no matter whether smoothing and filtering are applied or not. The comparison with GLDAS data supports that the signals of Tongji-GRACE02 over St. Lawrence River basin are close to those from CSR RL05, GFZ RL05a and JPL RL05, while the GLDAS result shows the best agreement with the Tongji-GRACE02 result.

VANDENBERG AFB, CALIF. - The first stage of the Delta II launch vehicle for the Gravity Probe B experiment is ready to be lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-15

VANDENBERG AFB, CALIF. - The first stage of the Delta II launch vehicle for the Gravity Probe B experiment is ready to be lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - Viewed from inside, the second stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-18

VANDENBERG AFB, CALIF. - Viewed from inside, the second stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The interstage of the Delta II launch vehicle for the Gravity Probe B experiment is moved into the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif., where it will be mated with the second stage. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-16

VANDENBERG AFB, CALIF. - The interstage of the Delta II launch vehicle for the Gravity Probe B experiment is moved into the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif., where it will be mated with the second stage. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The first stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-15

VANDENBERG AFB, CALIF. - The first stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The second stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-18

VANDENBERG AFB, CALIF. - The second stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The second stage of the Delta II launch vehicle for the Gravity Probe B experiment is moved into the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. Behind it can be seen the first stage of the Delta II. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-18

VANDENBERG AFB, CALIF. - The second stage of the Delta II launch vehicle for the Gravity Probe B experiment is moved into the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. Behind it can be seen the first stage of the Delta II. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - Workers on the mobile service tower at Space Launch Complex 2, Vandenberg Air Force Base, Calif., check the Delta II rocket’s second stage as it is mated with the first stage. The Delta II is the launch vehicle for the Gravity Probe B experiment, developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-18

VANDENBERG AFB, CALIF. - Workers on the mobile service tower at Space Launch Complex 2, Vandenberg Air Force Base, Calif., check the Delta II rocket’s second stage as it is mated with the first stage. The Delta II is the launch vehicle for the Gravity Probe B experiment, developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - In the spacecraft processing facility on North Vandenberg Air Force Base, the Gravity Probe B experiment sits on an assembly and test stand where it has been subject to various prelaunch testing. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-12

VANDENBERG AFB, CALIF. - In the spacecraft processing facility on North Vandenberg Air Force Base, the Gravity Probe B experiment sits on an assembly and test stand where it has been subject to various prelaunch testing. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The interstage of the Delta II launch vehicle for the Gravity Probe B experiment is prepared for lifting up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. It will enclose the second stage. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-16

VANDENBERG AFB, CALIF. - The interstage of the Delta II launch vehicle for the Gravity Probe B experiment is prepared for lifting up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. It will enclose the second stage. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The second stage of the Delta II launch vehicle for the Gravity Probe B experiment arrives at the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-12

VANDENBERG AFB, CALIF. - The second stage of the Delta II launch vehicle for the Gravity Probe B experiment arrives at the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The first stage of the Delta II launch vehicle for the Gravity Probe B experiment is raised to a vertical position at Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-15

VANDENBERG AFB, CALIF. - The first stage of the Delta II launch vehicle for the Gravity Probe B experiment is raised to a vertical position at Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The interstage of the Delta II launch vehicle for the Gravity Probe B experiment is moved into the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif., where it will be mated with the second stage. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-12

VANDENBERG AFB, CALIF. - The interstage of the Delta II launch vehicle for the Gravity Probe B experiment is moved into the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif., where it will be mated with the second stage. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - Viewed from inside, the second stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. Behind it is the first stage of the Delta II. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-18

VANDENBERG AFB, CALIF. - Viewed from inside, the second stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. Behind it is the first stage of the Delta II. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The interstage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. It will enclose the second stage. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-16

VANDENBERG AFB, CALIF. - The interstage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted up the mobile service tower on Space Launch Complex 2, Vandenberg Air Force Base, Calif. It will enclose the second stage. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

VANDENBERG AFB, CALIF. - The second stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted off the transporter after its arrival on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

NASA Image and Video Library

2003-09-18

VANDENBERG AFB, CALIF. - The second stage of the Delta II launch vehicle for the Gravity Probe B experiment is lifted off the transporter after its arrival on Space Launch Complex 2, Vandenberg Air Force Base, Calif. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

Equivalent water height extracted from GRACE gravity field model with robust independent component analysis

NASA Astrophysics Data System (ADS)

Guo, Jinyun; Mu, Dapeng; Liu, Xin; Yan, Haoming; Dai, Honglei

2014-08-01

The Level-2 monthly GRACE gravity field models issued by Center for Space Research (CSR), GeoForschungs Zentrum (GFZ), and Jet Propulsion Laboratory (JPL) are treated as observations used to extract the equivalent water height (EWH) with the robust independent component analysis (RICA). The smoothing radii of 300, 400, and 500 km are tested, respectively, in the Gaussian smoothing kernel function to reduce the observation Gaussianity. Three independent components are obtained by RICA in the spatial domain; the first component matches the geophysical signal, and the other two match the north-south strip and the other noises. The first mode is used to estimate EWHs of CSR, JPL, and GFZ, and compared with the classical empirical decorrelation method (EDM). The EWH STDs for 12 months in 2010 extracted by RICA and EDM show the obvious fluctuation. The results indicate that the sharp EWH changes in some areas have an important global effect, like in Amazon, Mekong, and Zambezi basins.

Brain stimulation and constraint for perinatal stroke hemiparesis: The PLASTIC CHAMPS Trial.

PubMed

Kirton, Adam; Andersen, John; Herrero, Mia; Nettel-Aguirre, Alberto; Carsolio, Lisa; Damji, Omar; Keess, Jamie; Mineyko, Aleksandra; Hodge, Jacquie; Hill, Michael D

2016-05-03

To determine whether the addition of repetitive transcranial magnetic stimulation (rTMS) and/or constraint-induced movement therapy (CIMT) to intensive therapy increases motor function in children with perinatal stroke and hemiparesis. A factorial-design, blinded, randomized controlled trial (clinicaltrials.gov/NCT01189058) assessed rTMS and CIMT effects in hemiparetic children (aged 6-19 years) with MRI-confirmed perinatal stroke. All completed a 2-week, goal-directed, peer-supported motor learning camp randomized to daily rTMS, CIMT, both, or neither. Primary outcomes were the Assisting Hand Assessment and the Canadian Occupational Performance Measure at baseline, and 1 week, 2 and 6 months postintervention. Outcome assessors were blinded to treatment. Interim safety analyses occurred after 12 and 24 participants. Intention-to-treat analysis examined treatment effects over time (linear mixed effects model). All 45 participants completed the trial. Addition of rTMS, CIMT, or both doubled the chances of clinically significant improvement. Assisting Hand Assessment gains at 6 months were additive and largest with rTMS + CIMT (β coefficient = 5.54 [2.57-8.51], p = 0.0004). The camp alone produced large improvements in Canadian Occupational Performance Measure scores, maximal at 6 months (Cohen d = 1.6, p = 0.002). Quality-of-life scores improved. Interventions were well tolerated and safe with no decrease in function of either hand. Hemiparetic children participating in intensive, psychosocial rehabilitation programs can achieve sustained functional gains. Addition of CIMT and rTMS increases the chances of improvement. This study provides Class II evidence that combined rTMS and CIMT enhance therapy-induced functional motor gains in children with stroke-induced hemiparetic cerebral palsy. © 2016 American Academy of Neurology.

KSC-03PD-2746

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. The Gravity Probe B experiment enters the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2744

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. At Vandenberg AFB, the canister enclosing the Gravity Probe B (GP-B) spacecraft is removed from the transporter. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

Proceedings of Hawaiian Winter Workshop (6th) on Dynamics of Oceanic Internal Gravity Waves Held in Manoa, Hawaii on 15-18 January 1991

DTIC Science & Technology

1991-11-01

Gravity Waves 12. PERSONAL AUTHOR(S) MUller, Peter and Henderson, Diane (eds.) 13a. TYPE OF REPORT 13b TIME COVERED 14. DATE OF REPORT (Year, Month, Day) 15...differ by 27r in defining the buoyancy scale.) Because the largest overturns must be several times larger than Dillon’s rms scale, LB is a good upper...0.6 times GM76 at 0.01 cpm. From there, they slope upward as k+ 0.0 7 and k+0 16. The shallow spectrum makes a sharp transition at the rolloff and

KSC-2011-3095

NASA Image and Video Library

2011-04-26

CAPE CANAVERAL, Fla. -- NASA's Gravity Recovery and Interior Laboratory, or GRAIL, mission logo on the side of the United Launch Alliance Delta II rocket that will loft the spacecraft into lunar orbit. The GRAIL mission is a part of NASA's Discovery Program. GRAIL will fly twin spacecraft in tandem orbits around the moon for several months to measure its gravity field. The mission also will answer longstanding questions about Earth's moon and provide scientists a better understanding of how Earth and other rocky planets in the solar system formed. GRAIL is scheduled to launch September 8, 2011. For more information visit: http://science.nasa.gov/missions/grail/. Photo credit: NASA/Jim Grossmann

Autolysis of Escherichia coli and Bacillus subtilis cells in low gravity

NASA Technical Reports Server (NTRS)

Kacena, M. A.; Smith, E. E.; Todd, P.

1999-01-01

The role of gravity in the autolysis of Bacillus subtilis and Escherichia coli was studied by growing cells on Earth and in microgravity on Space Station Mir. Autolysis analysis was completed by examining the death phase or exponential decay of cells for approximately 4 months following the stationary phase. Consistent with published findings, the stationary-phase cell population was 170% and 90% higher in flight B. subtilis and E. coli cultures, respectively, than in ground cultures. Although both flight autolysis curves began at higher cell densities than control curves, the rate of autolysis in flight cultures was identical to that of their respective ground control rates.

Weightbearing vs Gravity Stress Radiographs for Stability Evaluation of Supination-External Rotation Fractures of the Ankle.

PubMed

Seidel, Angela; Krause, Fabian; Weber, Martin

2017-07-01

Isolated lateral malleolar fractures may result from a supination-external rotation (SER) injury of the ankle. Stable fractures maintain tibiotalar congruence due to competent medial restraints and can be treated nonoperatively with excellent functional results and long-term prognosis. Stability might be assessed with either stress radiographs or weightbearing radiographs. A consecutive series of patients with closed SER fractures (presumed AO 44-B1) were prospectively enrolled from 2008 to 2015. Patients with clearly unstable fractures (medial clear space more than 7 mm) on the initial nonweightbearing radiograph were excluded and operated on. All other patients were examined with a gravity stress and a weightbearing anteroposterior radiograph. Borderline instability of the fracture was assumed when the medial clear space was 4 to 7 mm. Those were treated nonoperatively. Of 104 patients with isolated lateral malleolar fractures of the SER type, 14 patients were treated operatively because of clear instability (displacement) on the initial radiographs. Of the nonoperative patients, 44 patients demonstrated borderline instability on the gravity stress but stability on the weightbearing radiograph ("gravity borderline"); the remaining 46 were stable in both tests ("gravity stable"). At an average follow-up of 23 months, no significant differences were seen in the American Orthopaedic Foot & Ankle Society hindfoot score (92 points gravity-borderline group vs 93 points gravity-unstable group), the Foot Functional Index score (11 vs 10 points), the Short Form 36 (SF-36) physical component (86 vs 85 points), and SF-36 mental component (84 vs 81 points). Radiographically, all fractures had healed with anatomic congruity of the ankle. Weightbearing radiographs provided a reliable basis to decide about stability and nonoperative treatment in isolated lateral malleolar fractures of the SER type with excellent clinical and radiographic outcome at short-term follow-up. Gravity stress radiographs appear to overrate the need for operative treatment. Level III, prospective comparative study.

Cultures Traditionnelles de Plein Champ (Traditional Field Crops). Appropriate Technologies for Development. Peace Corps Information Collection & Exchange Reprint Series No. R-65.

ERIC Educational Resources Information Center

Leonard, David

Written in French, this manual, which deals with traditional field crops, is primarily designed to help Peace Corps volunteers develop and strengthen their agricultural skills. The focus of the manual is on surveying and interpreting local agricultural environment and individual farm units, developing agricultural extension techniques and…

Collaborating With an Urban Community to Develop an HIV and AIDS Prevention Program for Black Youth and Families

ERIC Educational Resources Information Center

Baptiste, Donna R.; Paikoff, Roberta L.; McKay, Mary McKernan; Madison-Boyd, Sybil; Coleman, Doris; Bell, Carl

2005-01-01

This article describes a collaboration between academic researchers and residents of a low-income, inner-city community to develop and deliver an HIV and AIDS prevention program for Black youth. The Chicago HIV Prevention and Adolescent Mental Health Project (CHAMP) Program was developed and implemented to decrease HIV and AIDS risk exposure among…

Environmental Quality Technology

DTIC Science & Technology

1992-01-01

34Flowthrough bioassay studies on the effects of antifouling TBT leachates." Tributyltin : Environmental Effects, M. A. Champ and P. F. Seligman, eds...organisms. Evaluating the effects of tributyltin on oysters by using the POMFRET system. NONPOINT $OURCE POLLUTION AQUATIC IMPACT PAHs AJR PETROLEUM...on effects of copper and tributyltin -based antifouling paint leachates." NOSC Technical Report 1060 (June). Henderson, R. S., and S. M. Salazar. 1991

Correlations between Geomagnetic Disturbances and Field-Aligned Currents during the 22-29 July 2004 Storm Time Interval

NASA Astrophysics Data System (ADS)

Hood, R.; Woodroffe, J. R.; Morley, S.; Aruliah, A. L.

2017-12-01

Using the CHAMP fluxgate magnetometer to calculate field-aligned current (FAC) densities and magnetic latitudes, with SuperMAG ground magnetometers analogously providing ground geomagnetic disturbances (GMD) magnetic perturbations and latitudes, we probe FAC locations and strengths as predictors of GMD locations and strengths. We also study the relationships between solar wind drivers and global magnetospheric activity, and both FACs and GMDs using IMF Bz and the Sym-H index. We present an event study of the 22-29 July 2004 storm time interval, which had particularly large GMDs given its storm intensity. We find no correlation between FAC and GMD magnitudes, perhaps due to CHAMP orbit limitations or ground magnetometer coverage. There is, however, a correlation between IMF Bz and nightside GMD magnitudes, supportive of their generation via tail reconnection. IMF Bz is also correlated with dayside FAC and GMD magnetic latitudes, indicating solar wind as an initial driver. The ring current influence increases during the final storm, with improved correlations between the Sym-H index and both FAC magnetic latitudes and GMD magnitudes. Sym-H index correlations may only be valid for higher intensity storms; a statistical analysis of many storms is needed to verify this.

The CDC Hemophilia A Mutation Project (CHAMP) Mutation List: a New Online Resource

PubMed Central

Payne, Amanda B.; Miller, Connie H.; Kelly, Fiona M.; Soucie, J. Michael; Hooper, W. Craig

2015-01-01

Genotyping efforts in hemophilia A (HA) populations in many countries have identified large numbers of unique mutations in the Factor VIII gene (F8). To assist HA researchers conducting genotyping analyses, we have developed a listing of F8 mutations including those listed in existing locus-specific databases as well as those identified in patient populations and reported in the literature. Each mutation was reviewed and uniquely identified using Human Genome Variation Society (HGVS) nomenclature standards for coding DNA and predicted protein changes as well as traditional nomenclature based on the mature, processed protein. Listings also include the associated hemophilia severity classified by International Society of Thrombosis and Haemostasis (ISTH) criteria, associations of the mutations with inhibitors, and reference information. The mutation list currently contains 2,537 unique mutations known to cause HA. HA severity caused by the mutation is available for 2,022 mutations (80%) and information on inhibitors is available for 1,816 mutations (72%). The CDC Hemophilia A Mutation Project (CHAMP) Mutation List is available at http://www.cdc.gov/hemophiliamutations for download and search and will be updated quarterly based on periodic literature reviews and submitted reports. PMID:23280990

English language proficiency and physical activity among Mexican-origin women in South Texas and South Carolina.

PubMed

Salinas, Jennifer J; Hilfinger Messias, DeAnne K; Morales-Campos, Daisy; Parra-Medina, Deborah

2014-02-01

To examine the relationship between English language proficiency (ELP), physical activity, and physical activity-related psychosocial measures (i.e., exercise self-efficacy, exercise social support, perceptions of environmental supports) among Mexican-origin women in South Carolina and Texas. Adjusted robust regression and interaction modeling to evaluate baseline questionnaire data on self-reported ELP with CHAMPS leisure-time moderate-to-vigorous physical activity (MVPA), accelerometry data, Physical Activity Self-Efficacy, Physical Activity Social Support, and Environmental Support for Physical Activity in 118 Mexican-origin women. The adjusted regression revealed a significant association between ELP and perceived physical activity self-efficacy (β = 234.2, p = .004), but not with physical activity social support. In South Carolina, CHAMPS leisure-time MVPA (411.4 versus 114.3 minutes, p < .05) was significantly different between women in the high ELP quartile and those in the very low quartile. Among high ELP Mexican-origin women, participants in Texas reported significantly higher MVPA measured by accelerometry (p = .042) than those in South Carolina. Our findings indicate that ELP was associated with physical activity and that contextual factors may also play a role.

Thermosphere Response to Geomagnetic Variability during Solar Minimum Conditions

NASA Astrophysics Data System (ADS)

Forbes, Jeffrey; Gasperini, Federico; Zhang, Xiaoli; Doornbos, Eelco; Bruinsma, Sean; Haeusler, Kathrin; Hagan, Maura

2015-04-01

The response of thermosphere mass density to variable geomagnetic activity at solar minimum is revealed as a function of height utilizing accelerometer data from GRACE near 480 km, CHAMP near 320 km, and GOCE near 260 km during the period October-December, 2009. The GOCE data at 260 km, and to some degree the CHAMP measurements at 320 km, reveal the interesting feature that the response maximum occurs at low latitudes, rather than at high latitudes where the geomagnetic energy input is presumed to be deposited. The latitude distribution of the response is opposite to what one might expect based on thermal expansion and/or increase in mean molecular weight due to vertical transport of N2 at high latitudes. We speculate that what is observed reflects the consequences of an equatorward meridional circulation with downward motion and compressional heating at low latitudes. A numerical simulation using the National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Mesosphere Electrodynamics General Circulation Model (TIME-GCM) is used to assist with this diagnosis. At 480 km GRACE reveals maximum density responses at high southern (winter) latitudes, consistent with recent interpretations in terms of compositional versus temperature effects near the oxygen-helium transition altitude during low solar activity.

Large-scale traveling atmospheric disturbances (LSTADs) in the thermosphere inferred from CHAMP, GRACE, and SETA accelerometer data

NASA Astrophysics Data System (ADS)

Bruinsma, Sean L.; Forbes, Jeffrey M.

2010-08-01

Densities derived from accelerometer measurements on the GRACE, CHAMP, and Air Force/SETA satellites near 490, 390, and 220 km, respectively, are used to elucidate global-scale characteristics of traveling atmospheric disturbances (TADs). Several characteristics elucidated in numerical simulations are confirmed in this study, namely: (1) propagation speeds increase from the lower thermosphere to the upper thermosphere; (2) propagation to the equator and even into the opposite hemisphere can occur; (3) greater attenuation of TADs occurs during daytime and at higher levels of solar activity (i.e., more wave activity during nighttime and solar minimum), presumably due to the greater influence of ion drag. In addition, we find that the occurrence of significant TAD activity emanating from the auroral regions does not reflect a clear relation with the level of planetary magnetic activity as measured by Kp. There is also evidence of waves originating in the tropics, presumably due to convective sources; to some extent this may contribute to the Kp and solar flux relationships noted above. Further elucidation of local time, season, and altitude dependences of TAD propagation characteristics may be forthcoming from density measurements from the GOCE and Swarm missions.

Etudes optiques de nouveaux materiaux laser: Des orthosilicates dopes a l'ytterbium: Le yttrium (lutetium,scandium) pentoxide de silicium

NASA Astrophysics Data System (ADS)

Denoyer, Aurelie

La decouverte et l'elaboration de nouveaux materiaux laser solides suscitent beaucoup d'interet parmi la communaute scientifique. En particulier les lasers dans la gamme de frequence du micron debouchent sur beaucoup d'applications, en telecommunication, en medecine, dans le domaine militaire, pour la, decoupe des metaux (lasers de puissance), en optique non lineaire (doublage de frequence, bistabilite optique). Le plus couramment utilise actuellement est le Nd:YAG dans cette famille de laser, mais des remplacants plus performants sont toujours recherches. Les lasers a base d'Yb3+ possedent beaucoup d'avantages compares aux lasers Nd3+ du fait de leur structure electronique simple et de leur deterioration moins rapide. Parmi les matrices cristallines pouvant accueillir l'ytterbium, les orthosilicates Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5 se positionnent tres bien, du fait de leur bonne conductivite thermique et du fort eclatement de leur champ cristallin necessaire a l'elaboration de lasers quasi-3 niveaux. De plus l'etude fine et systematique des proprietes microscopiques de nouveaux materiaux s'avere toujours tres interessante du point de vue de la recherche fondamentale, c'est ainsi que de nouveaux modeles sont concus (par exemple pour le champ cristallin) ou que de nouvelles proprietes inhabituelles sont decouvertes, menant a de nouvelles applications. Ainsi d'autres materiaux dopes a l'ytterbium sont connus pour leurs proprietes de couplage electron-phonon, de couplage magnetique, d'emission cooperative ou encore de bistabilite optique, mais ces proprietes n'ont encore jamais ete mises en evidence dans Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5. Ainsi, cette these a pour but l'etude des proprietes optiques et des interactions microscopiques dans Yb:Y2SiO 5, Yb:Lu2SiO5 et Yb:Sc2SiO5. Nous utilisons principalement les techniques d'absorption IR et de spectroscopie Raman pour determiner les excitations du champ cristallin et les modes de vibration dans le materiau. Des mesures optiques sous champ magnetique ont egalement ete effectuees dans le but de caracteriser le comportement de ces excitations lorsqu'elles sont soumises a l'effet Zeeman. La resonance paramagnetique electronique a permis de completer cette etude de l'eclatement Zeeman suivant toutes les orientations du cristal. Enfin la fluorescence par excitation selective et la fluorescence induite par Raman FT, completent la description des niveaux d'energie et revelent l'existence d'emission cooperative de deux ions Yb3+ et de transferts d'energie. Les resultats de cette these apportent une contribution originale dans le domaine des nouveaux materiaux lasers par l'etude et la comprehension des interactions fines et des proprietes microscopiques d'un materiau en particulier. Ils debouchent a la fois sur des applications possibles dans le domaine de l'optique et des lasers, et sur la comprehension d'aspects fondamentaux. Cette these a prouve l'interet de ces matrices pour leur utilisation comme lasers solides: un fort eclatement du champ cristallin favorable a l'elaboration de laser quasi-3 niveaux, et de larges bandes d'absorption (dues a un fort couplage electron-phonon et a des raies satellites causees par une interaction d'echange entre deux ions Yb3+) qui permettent la generation d'impulsions laser ultra-courtes, l'accordabilite du laser, etc. De plus la miniaturisation des lasers est possible pour l'optique integree grace a des couches minces synthetisees par epitaxie en phase liquide dont nous avons demontre la tres bonne qualite structurale et l'ajustement possible de certains parametres. Nous avons reconstruit le tenseur g du niveau fondamental (qui donne des informations precieuses sur les fonctions d'onde), ceci dans le but d'aider les theoriciens a concevoir un modele de champ cristallin valide. Plusieurs mecanismes de transferts d'energie ont ete mis en evidence: un mecanisme de relaxation d'un site vers l'autre, un mecanisme d'emission cooperative, et un mecanisme d'excitation de l'Yb3+ par le Tm3+ (impurete presente dans le materiau). Ces transferts sont plutot nefastes pour la fabrication d'un laser mais sont interessants pour l'optique non lineaire (doublage de frequence, memoires optiques). Enfin, plusieurs elements (le couplage magnetique de paire, le couplage electron-phonon et l'emission cooperative) nous ont permis de conclure sur le caractere covalent de la matrice. Nous avons d'ailleurs demontre ici le role de la covalence dans l'emission cooperative, transition habituellement attribuee aux interactions multipolaires electriques.

A Test Run of the EGSIEM Near Real-Time Service Based on GRACE Mission Data

NASA Astrophysics Data System (ADS)

Kvas, A.; Gruber, C.; Gouweleeuw, B.; Guntner, A.; Mayer-Gürr, T.; Flechtner, F. M.

2017-12-01

To enable the use of GRACE and GRACE-FO data for rapid monitoring applications, the EGSIEM (European Gravity Service for Improved Emergency Management) project, funded by the Horizon 2020 Framework Program for Research and Innovation of the European Union, has implemented a demonstrator for a near real-time (NRT) gravity field service. The goal of this service is to provide daily gravity field solutions with a maximum latency of five days. For this purpose, two independent approaches were developed at the German Research Centre for Geosciences (GFZ) and Graz University of Technology (TUG). Based on these daily gravity field solutions, statistical flood and drought indicators are derived by the EGSIEM Hydrological Service, developed at GFZ. The NRT products are subsequently provided to the Center for Satellite based Crisis Information (ZKI) at the German Aerospace Center as well as the Global Flood Awareness System (GloFAS) at the Joint Research Center of the European Commission. In the first part of this contribution, the performance of the service based on a statistical analysis of historical flood events during the GRACE period is evaluated. Then, results from the six month long operational test run of the service which started on April 1st 2017 are presented and a comparison between historical and operational gravity products and flood indicators is made.

Glacial isostatic adjustment on the Northern Hemisphere - new results from GRACE

NASA Astrophysics Data System (ADS)

Mueller, J.; Steffen, H.; Gitlein, O.; Denker, H.; Timmen, L.

2007-12-01

The Earth's gravity field mapped by the Gravity Recovery and Climate Experiment (GRACE) satellite mission shows variations due to the integral effect of mass variations in the atmosphere, hydrosphere and geosphere. The Earth's gravity field is provided in form of monthly solutions by several institutions, e.~g. GFZ Potsdam, CSR and JPL. During the GRACE standard processing of these analysis centers, oceanic and atmospheric contributions as well as tidal effects are reduced. The solutions of the analysis centers differ slightly, which is due the application of different reduction models and center-specific processing schemes. We present our investigation of mass variations in the areas of glacial isostatic adjustment (GIA) in North America and Northern Europe from GRACE data. One key issue is the separation of GIA parts and the reduction of the observed quantities by applying dedicated filters (e.~g. isotropic, non-isotropic, and destriping filters) and global models of hydrological variations (e.~g. WGHM, LaDWorld, GLDAS). In a further step, we analyze the results of both regions regarding their reliability, and finally present a comparison to results of a geodynamical modeling and absolute gravity measurements. Our results clearly show that the quality of the GRACE-derived gravity- change signal benefits from improved reduction models and chosen analysis techniques. Nevertheless, the comparison to results of geodynamic models still reveals differences, and thus further studies are in progress.

Time-Variable Gravity from Satellite Laser-Ranging: The Low-Degree Components and Their Connections with Geophysical/Climatic Changes

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Cox, Christopher M.

2004-01-01

Satellite laser-ranging (SLR) has been observing the tiny variations in Earth s global gravity for over 2 decades. The oblateness of the Earth's gravity field, J2, has been observed to undergo a secular decrease of J2 due mainly to the post-glacial rebound of the mantle. Sometime around 1998 this trend reversed quite suddenly. This reversal persisted until 2001, at which point the atmosphere-corrected time series appears to have reversed yet again towards normal. This anomaly signifies a large interannual change in global mass distribution. A number of possible causes have been considered, with oceanic mass redistribution as the leading candidate although other effects, such as glacial melting and core effects may be contributing. In fact, a strong correlation has been found between the J2 variability and the Pacific decadal oscillation. It is relatively more difficult to solve for corresponding signals in the shorter wavelength harmonics from the existing SLR-derived time variable gravity results, although it appears that geophysical fluid mass transport is being observed. For example, the recovered J3 time series shows remarkable agreement with NCEP-derived estimates of atmospheric gravity variations. Likewise, some of the non-zonal harmonic components have significant interannual signal that appears to be related to mass transport related to climatic effects such as El Nino Southern Oscillation. We will present recent updates on the J2 evolution, as well as a monthly time sequence of low-degree component map of the time-variable gravity complete through degree 4, and examine possible geophysical/climatic causes.

Implications of postseismic gravity change following the great 2004 Sumatra-Andaman earthquake from the regional harmonic analysis of GRACE intersatellite tracking data

USGS Publications Warehouse

Han, S.-C.; Sauber, J.; Luthcke, S.B.; Ji, C.; Pollitz., F. F.

2008-01-01

We report Gravity Recovery and Climate Experiment (GRACE) satellite observations of coseismic displacements and postseismic transients from the great Sumatra-Andaman Islands (thrust event; Mw ???9.2) earthquake in December 2004. Instead of using global spherical harmonic solutions of monthly gravity fields, we estimated the gravity changes directly using intersatellite range-rate data with regionally concentrated spherical Slepian basis functions every 15-day interval. We found significant step-like (coseismic) and exponential-like (postseismic) behavior in the time series of estimated coefficients (from May 2003 to April 2007) for the spherical Slepian function's. After deriving coseismic slip estimates from seismic and geodetic data that spanned different time intervals, we estimated and evaluated postseismic relaxation mechanisms with alternate asthenosphere viscosity models. The large spatial coverage and uniform accuracy of our GRACE solution enabled us to clearly delineate a postseismic transient signal in the first 2 years of postearthquake GRACE data. Our preferred interpretation of the long-wavelength components of the postseismic avity change is biviscous viscoelastic flow. We estimated a transient viscosity of 5 ??17 Pa s and a steady state viscosity of 5 ?? 1018 - 1019 Pa s. Additional years of the GRACE observations should provide improved steady state viscosity estimates. In contrast to our interpretation of coseismic gravity change, the prominent postearthquake positive gravity change around the Nicobar Islands is accounted for by seafloor uplift with less postseismic perturbation in intrinsic density in the region surrounding the earthquake. Copyright 2008 by the American Geophysical Union.

Two components of postseismic gravity changes of megathrust earthquakes from satellite gravimetry

NASA Astrophysics Data System (ADS)

Tanaka, Y.; Heki, K.

2013-12-01

There are several reports of the observations of gravity changes due to megathrust earthquakes with data set of Gravity Recovery And Climate Experiment (GRACE) satellite. We analyzed the co- and postseismic gravity changes of the three magnitude 9 class earthquakes, the 2004 Sumatra-Andaman, the 2010 Chile (Maule), and the 2011 Tohoku-Oki earthquakes, using the newly released data (Release 05 data) set. In addition to the coseismic steps, these earthquakes showed a common feature that the postseismic changes include two components with different polarity and time constants, i.e. rapid decreases over a few months, followed by slow increases lasting for years. This is shown in the auxiliary figure of this abstract. In this figure, the white circles are the data whose seasonal and secular changes were removed. The vertical translucent lines denote the earthquake occurrence times. All the three earthquakes suggest the existence of two postseismic gravity change components with two distinct time constants. The first (short-term) component showed geographical distribution similar to the coseismic changes, but the position of the largest gravity decrease shifted toward the trench. The short-term components can be related to afterslip, but their time constants and distributions showed significant deviation from gravity changes predicted by the afterslip models. The second (long-term) components are characterized by positive gravity changes with the peak close to the trench axis. The long-term components should be attributed to different or multiple mechanisms, e.g. viscous relaxation of rocks in the upper mantle [Han and Simons, 2008; Panet et al., 2007] and diffusion of supercritical water around the down-dip end of the ruptured fault [Ogawa and Heki, 2007]. Both of the two mechanisms can explain the postseismic gravity increase in this timescale to some extent, but there have been no decisive evidence to prove or disprove either one of these. But generally speaking, postseismic crustal movements measured by GPS do not show such polarity reversals. This suggests that satellite gravimetry can separate two independent physical postseismic processes that are not discernible by observing only surface crustal movements.

The complete spectrum of the equatorial electrojet related to solar tides: CHAMP observations

NASA Astrophysics Data System (ADS)

Lühr, H.; Manoj, C.

2013-08-01

Based on 10 yr of magnetic field measurements by the CHAMP satellite we draw a detailed picture of the equatorial electrojet (EEJ) tidal variations. For the first time the complete EEJ spectrum related to average solar tides has been compiled. A large fraction of the resulting spectrum is related to the switch on/off of the EEJ between day and night. This effect has carefully been considered when interpreting the results. As expected, largest amplitudes are caused by the migrating tides representing the mean diurnal variation. Higher harmonics of the daily variations show a 1/f fall-off in amplitude. Such a spectrum is required to represent the vanishing of the EEJ current at night. The migrating tidal signal exhibits a distinct annual variation with large amplitudes during December solstice and equinox seasons but a depression by a factor of 1.7 around June-July. A rich spectrum of non-migrating tidal effects is deduced. Most prominent is the four-peaked longitudinal pattern around August. Almost 90% of the structure can be attributed to the diurnal eastward-propagating tide DE3. In addition the westward-propagating DW5 is contributing to wave-4. The second-largest non-migrating tide is the semi-diurnal SW4 around December solstice. It causes a wave-2 feature in satellite observations. The three-peaked longitudinal pattern, often quoted as typical for the December season, is significantly weaker. During the months around May-June a prominent wave-1 feature appears. To first order it represents a stationary planetary wave SPW1 which causes an intensification of the EEJ at western longitudes beyond 60° W and a weakening over Africa/India. In addition, a prominent ter-diurnal non-migrating tide TW4 causes the EEJ to peak later, at hours past 14:00 local time in the western sector. A particularly interesting non-migrating tide is the semi-diurnal SW3. It causes largest EEJ amplitudes from October through December. This tidal component shows a strong dependence on solar flux level with increasing amplitudes towards solar maximum. We are not aware of any previous studies mentioning this behaviour of SW3. The main focus of this study is to present the observed EEJ spectrum and its relation to tidal driving. For several of the identified spectral components we cannot offer convincing explanations for the generation mechanisms.

Un champ semantique: les noms d'appartenance raciale au Honduras britannique (A Semantic Field: Names of Racial Identity in the British Honduras)

ERIC Educational Resources Information Center

Tabouret-Keller, Andree

1975-01-01

This article studies the problem of social identity among six different racial groups in the British Honduras, focusing on what the groups call themselves and what others call them, and on the semantic field of these terms, i.e. the socio-cultural values they represent. (Text is in French.) (AM)

ENVIRONMENTAL TECHNOLOGY VERIFICATION JOINT (NSF-EPA) VERIFICATION STATEMENT AND REPORT, PERFORMANCE OF INDUCTION MIXERS FOR DISINFECTION OF WET WEATHER FLOWS, US FILTER/STRANCO PRODUCTS WATER CHAMP R F SERIES CHEMICAL INDUCTION SYSTEM

EPA Science Inventory

The Wet-Weather Flow Technologies Pilot of the EPA's Technology Verification (ETV) Program under a partnership with NSF International has verified the performawnce of the USFilter/Stranco Products chemical induction mixer used for disinfection of wet-weather flows. The USFilter t...

Multi-Target Single Cycle Instrument Placement

NASA Technical Reports Server (NTRS)

Pedersen, Liam; Smith, David E.; Deans, Matthew; Sargent, Randy; Kunz, Clay; Lees, David; Rajagopalan, Srikanth; Bualat, Maria

2005-01-01

This presentation is about the robotic exploration of Mars using multiple targets command cycle, safe instrument placements, safe operation, and K9 Rover which has a 6 wheel steer rocket-bogey chassis (FIDO, MER), 70% MER size, 1.2 GHz Pentium M laptop running Linux OS, Odometry and compass/inclinometer, CLARAty architecture, 5 DOF manipulator w/CHAMP microscopic camera, SciCams, NavCams and HazCams.

Study of the Electric Field-Induced Low Temperature Phase in Pb(Mg_{1/3}Nb_{2/3})O_3: Titanium Influence

NASA Astrophysics Data System (ADS)

Bidault, O.; Husson, E.; Gaucher, P.

1997-06-01

The temperature dependence of the dielectric permittivity under a dc electric field is studied in (1 - x)Pb(Mg{1/3}Nb{2/3})O3-xPbTiO3 ceramics (0 leq x leq 0.1). The size of the ordered regions, which is the key parameter to understand the dielectric response of such materials, is suggested to be reduced by T_i doping. A ferroelectric transition can be induced by a field E from the average cubic phase. Whereas PMN is a relaxor undergoing a macroscopic phase transition only if E > 4 kV cm^{-1}, materials with x = 0.1 exhibit a spontaneous cubic to rhombohedral transition at 280 K on cooling. Moreover, in all the studied samples, the T_f temperature deduced from the Vogel-Fulcher relation is found to be very close to the poling temperature under high field. La variation en température de la constante diélectrique de céramiques de composition (1 - x)Pb(Mg{1/3}Nb{2/3})O{3}-xPbTiO3 (0 leq x leq 0,1) est étudiée alors qu'un champ dc est appliqué à l'échantillon. La taille des régions ordonnées, paramètre-clé pour comprendre la réponse du matériau, est réduite par l'introduction de titane. Une transition de phase ferroélectrique peut être induite sous champ à partir de la phase cubique en moyenne. Si PMN est un relaxeur, ne transitant qu'à condition d'avoir E > 4 kV cm^{-1}, la transition cubique to rhomboèdrique devient spontanée pour PMN: 10% T_i (à 280 K au refroidissement). De plus, pour tous les échantillons, la température T_f, déduite de la relation de Vogel-Fulcher est systématiquement trouvée voisine de celle d'apparition de la phase polaire sous champ.

CHAMP: Cognitive behaviour therapy for health anxiety in medical patients, a randomised controlled trial

PubMed Central

2011-01-01

Background Abnormal health anxiety, also called hypochondriasis, has been successfully treated by cognitive behaviour therapy (CBT) in patients recruited from primary care, but only one pilot trial has been carried out among those attending secondary medical clinics where health anxiety is likely to be more common and have a greater impact on services. The CHAMP study extends this work to examine both the clinical and cost effectiveness of CBT in this population. Method/Design The study is a randomized controlled trial with two parallel arms and equal randomization of 466 eligible patients (assuming a 20% drop-out) to an active treatment group of 5-10 sessions of cognitive behaviour therapy and to a control group. The aim at baseline, after completion of all assessments but before randomization, was to give a standard simple explanation of the nature of health anxiety for all participants. Subsequently the control group was to receive whatever care might usually be available in the clinics, which is normally a combination of clinical assessment, appropriate tests and reassurance. Those allocated to the active treatment group were planned to receive between 5 and 10 sessions of an adapted form of cognitive behaviour therapy based on the Salkovskis/Warwick model, in which a set of treatment strategies are chosen aimed at helping patients understand the factors that drive and maintain health anxiety. The therapy was planned to be given by graduate research workers, nurses or other health professionals trained for this intervention whom would also have their competence assessed independently during the course of treatment. The primary outcome is reduction in health anxiety symptoms after one year and the main secondary outcome is the cost of care after two years. Discussion This represents the first trial of adapted cognitive behaviour therapy in health anxiety that is large enough to test not only the clinical benefits of treatment but also whether the cost of treatment is offset by savings from reduced use of other health services in comparison to the control group. Cognitive behaviour therapy for Health Anxiety in Medical Patients (CHAMP) Trial registration Current Controlled Trials ISRCTN14565822 PMID:21672205

Field Line Mapping of the Polar Cap Neutral Density Anomaly

NASA Astrophysics Data System (ADS)

Sutton, E. K.; Lin, C. S.; Huang, C. Y.; Cooke, D. L.

2016-12-01

Polar cap neutral density anomaly (PCNDA) events of localized density enhancement with a half size around 700-1000 km had been frequently detected by CHAMP satellite at around 400 km during major magnetic storms with Dst < -100 nT. Density enhancement is probably produced via Joule heating of the thermosphere when a significant amount of energy is deposited in the polar cap. We have identified 12 PCNDA events measured by CHAMP during two major magnetic storms including one initiated by a large solar wind pressure pulse. Their density anomaly locations are found to scatter randomly within the polar circle of 80o magnetic latitude in the geomagnetic coordinate. However after transformed to the Geocentric Solar Wind (GSW) coordinates, their locations become aligned in the direction of solar wind velocity. To better understand the polar cap energy deposition we trace magnetic field lines to the magnetosphere up to 30 earth radii from the ionosphere at 400 km using the data-based Tsyganenko T95 and TS05 magnetic field models. Field line tracing is performed in the GSW coordinate along the CHAMP orbit as well as for the whole polar cap. Each traced magnetic field line is classified into one of the three categories, (1) magnetosphere closed field line (MC) crossing the equatorial plane within 30 earth radii, (2) open field line connected to the magnetopause (MP), or (3) open field line connected to the magnetotail lobe (MT). For nine PCNDA events among the 10 events that we are able to conduct tracing, field lines originated from the density anomaly regions are classified as MT. Only one outlier event in association with a very large IMF BZ is classified as MP. Furthermore the separation angle between the density anomaly peak and the MP-MT field line separation point at 400 km on the X- and Z-axes meridian plane varies from -4o to 16o. Based on these results we speculate that convective electric fields and field aligned currents in the ionosphere might be enhanced near the MP-MT separation point during magnetic storms, resulting in intense localized Joule heating of the thermosphere.

Investigation of the high-frequency attenuation parameter, κ (kappa), from aftershocks of the 2010 Mw 8.8 Maule, Chile earthquake

USGS Publications Warehouse

Neighbors, Corrie; Liao, E. J.; Cochran, Elizabeth S.; Funning, G. J.; Chung, A. I.; Lawrence, J. F.; Christensen, C. M.; Miller, M.; Belmonte, A.; Sepulveda, H. H. Andrés

2014-01-01

The Bío Bío region of Chile experienced a vigorous aftershock sequence following the 2010 February 27 Mw 8.8 Maule earthquake. The immediate aftershock sequence was captured by two temporary seismic deployments: the Quake Catcher Network Rapid Aftershock Mobilization Program (QCN RAMP) and the Incorporated Research Institutions for Seismology CHile Aftershock Mobilization Program (IRIS CHAMP). Here, we use moderate to large aftershocks (ML ≥ 4.0) occurring between 2010 March 1 and June 30 recorded by QCN RAMP and IRIS CHAMP stations to determine the spectral decay parameter, kappa (κ). First, we compare waveforms and κ estimates from the lower-resolution QCN stations to the IRIS CHAMP stations to ensure the QCN data are of sufficient quality. We find that QCN stations provide reasonable estimates of κ in comparison to traditional seismic sensors and provide valuable additional observations of local ground motion variation. Using data from both deployments, we investigate the variation in κ for the region to determine if κ is influenced primarily by local geological structure, path attenuation, or source properties (e.g. magnitude, mechanism and depth). Estimates of κ for the Bío Bío region range from 0.0022 to 0.0704 s with a mean of 0.0295 s and are in good agreement with κ values previously reported for similar tectonic environments. κ correlates with epicentral distance and, to a lesser degree, with source magnitude. We find little to no correlation between the site kappa, κ0, and mapped geology, although we were only able to compare the data to a low-resolution map of surficial geology. These results support an increasing number of studies that suggest κobservations can be attributed to a combination of source, path and site properties; additionally, measured κ are often highly scattered making it difficult to separate the contribution from each of these factors. Thus, our results suggest that contributions from the site, path and source should be carefully considered when interpreting κ values.

Effect of prehatching weightlessness on adult fish behavior in dynamic environments

NASA Technical Reports Server (NTRS)

Hoffman, R. B.; Salinas, G. A.; Boyd, J. F.; Baky, A. A.; Von Baumgarten, R. J.

1978-01-01

At 16-17 months of age, three groups of fish from the embryonated eggs in the ASTP killifish experiment were subjected to postflight tests consisting of rapidly changing environments. It was found that the group of fish with the least amount of development at orbital insertion (A-32) had a decreased rheotropism for both the moving background and the rotating water current tests when compared to ground control fish. Exposure to parabolic aircraft flight conditions revealed that the A-32 fish were less disoriented during zero gravity periods and were hypersensitive to high-gravity periods. These results suggested a modified vestibular competency due to a 9-d prehatching weightlessness exposure.

KSC-03PD-2745

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. A transporter carrying the Gravity Probe B experiment backs into the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2748

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. The Gravity Probe B experiment is lowered onto an assembly and test stand in the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2749

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. The Gravity Probe B experiment rests on an assembly and test stand in the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2747

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. The Gravity Probe B experiment is lifted from its transporter in the spacecraft processing facility on North Vandenberg Air Force Base. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2742

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. Enclosed in a canister, the Gravity Probe B (GP-B) spacecraft arrives on Vandenberg Air Force Base, headed for the spacecraft processing facility. Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2743

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. Enclosed in a canister, the Gravity Probe B (GP-B) spacecraft arrives at the spacecraft processing facility on North Vandenberg Air Force Base . Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2881

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. Logos identify the mission of this Delta II rocket that will launch the Gravity Probe B experiment, developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The targeted launch date is Dec. 6, 2003.

KSC-03PD-2880

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. Logos identify the mission of this Delta II rocket that will launch the Gravity Probe B experiment, developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The targeted launch date is Dec. 6, 2003.

Evaluation of recent GRACE monthly solution series with an ice sheet perspective

NASA Astrophysics Data System (ADS)

Horwath, Martin; Groh, Andreas

2016-04-01

GRACE monthly global gravity field solutions have undergone a remarkable evolution, leading to the latest (Release 5) series by CSR, GFZ, and JPL, to new series by other processing centers, such as ITSG and AIUB, as well as to efforts to derive combined solutions, particularly by the EGSIEM (European Gravity Service for Improved Emergency Management) project. For applications, such as GRACE inferences on ice sheet mass balance, the obvious question is on what GRACE solution series to base the assessment. Here we evaluate different GRACE solution series (including the ones listed above) in a unified framework. We concentrate on solutions expanded up to degree 90 or higher, since this is most appropriate for polar applications. We empirically assess the error levels in the spectral as well as in the spatial domain based on the month-to-month scatter in the high spherical harmonic degrees. We include empirical assessment of error correlations. We then apply all series to infer Antarctic and Greenland mass change time series and compare the results in terms of apparent signal content and noise level. We find that the ITSG solutions show lowest noise level in the high degrees (above 60). A preliminary combined solution from the EGSIEM project shows lowest noise in the degrees below 60. This virtue maps into the derived ice mass time series, where the EGSIEM-based results show the lowest noise in most cases. Meanwhile, there is no indication that any of the considered series systematically dampens actual geophysical signals.

Detecting atmospheric normal modes with periods less than 6 h by barometric observations

NASA Astrophysics Data System (ADS)

Ermolenko, S. I.; Shved, G. M.; Jacobi, Ch.

2018-04-01

The theory of atmospheric normal modes (ANMs) predicts the existence of relatively short-period gravity-inertia ANMs. Simultaneous observations of surface air-pressure variations by barometers at distant stations of the Global Geodynamics Project network during an interval of 6 months were used to detect individual gravity-inertia ANMs with periods of ∼2-5 h. Evidence was found for five ANMs with a lifetime of ∼10 days. The data of the stations, which are close in both latitude and longitude, were utilized for deriving the phases of the detected ANMs. The phases revealed wave propagation to the west and increase of zonal wavenumbers with frequency. As all the detected gravity-inertia ANMs are westward propagating, they are suggested to be generated due to the breakdown of migrating solar tides and/or large-scale Rossby waves. The existence of an ANM background will complicate the detection of the translational motions of the Earth's inner core.

Satellite radio occultation investigations of internal gravity waves in the planetary atmospheres

NASA Astrophysics Data System (ADS)

Kirillovich, Ivan; Gubenko, Vladimir; Pavelyev, Alexander

Internal gravity waves (IGWs) modulate the structure and circulation of the Earth’s atmosphere, producing quasi-periodic variations in the wind velocity, temperature and density. Similar effects are anticipated for the Venus and Mars since IGWs are a characteristic of stably stratified atmosphere. In this context, an original method for the determination of IGW parameters from a vertical temperature profile measurement in a planetary atmosphere has been developed [Gubenko et al., 2008, 2011, 2012]. This method does not require any additional information not contained in the profile and may be used for the analysis of profiles measured by various techniques. The criterion for the IGW identification has been formulated and argued. In the case when this criterion is satisfied, the analyzed temperature fluctuations can be considered as wave-induced. The method is based on the analysis of relative amplitudes of the wave field and on the linear IGW saturation theory in which these amplitudes are restricted by dynamical (shear) instability processes in the atmosphere. When the amplitude of an internal wave reaches the shear instability threshold, energy is assumed to be dissipated in such a way that the IGW amplitude is maintained at the instability threshold level as the wave propagates upwards. We have extended the developed technique [Gubenko et al., 2008] in order to reconstruct the complete set of wave characteristics including such important parameters as the wave kinetic and potential energy per unit mass and IGW fluxes of the energy and horizontal momentum [Gubenko et al., 2011]. We propose also an alternative method to estimate the relative amplitudes and to extract IGW parameters from an analysis of perturbations of the Brunt-Vaislala frequency squared [Gubenko et al., 2011]. An application of the developed method to the radio occultation (RO) temperature data has given the possibility to identify the IGWs in the Earth's, Martian and Venusian atmospheres and to determine the magnitudes of key wave parameters such as the intrinsic frequency, amplitudes of vertical and horizontal wind velocity perturbations, vertical and horizontal wavelengths, intrinsic vertical and horizontal phase (and group) speeds, kinetic and potential energy per unit mass, vertical fluxes of the wave energy and horizontal momentum. Vertical profiles of temperature retrieved from RO measurements of the CHAMP (Earth), Mars Global Surveyor (Mars), Magellan and Venus Express (Venus) missions are used and analyzed to identify discrete or “narrow spectral” wave events and to determine IGW characteristics in the Earth’s, Martian and Venusian atmospheres. This work was partially supported by the RFBR grant 13-02-00526-a and Program 22 of the RAS Presidium. References. Gubenko V.N., Pavelyev A.G., Andreev V.E. Determination of the intrinsic frequency and other wave parameters from a single vertical temperature or density profile measurement // J. Geophys. Res. 2008. V. 113. No.D08109, doi:10.1029/2007JD008920. Gubenko V.N., Pavelyev A.G., Salimzyanov R.R., Pavelyev A.A. Reconstruction of internal gravity wave parameters from radio occultation retrievals of vertical temperature profiles in the Earth’s atmosphere // Atmos. Meas. Tech. 2011. V. 4. No.10. P. 2153-2162, doi:10.5194/amt-4-2153-2011. Gubenko V.N., Pavelyev A.G., Salimzyanov R.R., Andreev V.E. A method for determination of internal gravity wave parameters from a vertical temperature or density profile measurement in the Earth’s atmosphere // Cosmic Res. 2012. V. 50. No.1. P. 21-31, doi: 10.1134/S0010952512010029.

Wave Coupling in the Atmosphere-Ionosphere System

NASA Astrophysics Data System (ADS)

Forbes, J. M.

2016-12-01

Vertically-propagating solar and lunar tides, Kelvin waves, gravity waves (GW) and planetary waves (PW) constitute the primary mechanism for transmitting lower atmosphere variability to the upper atmosphere and ionosphere. Vertically propagating waves grow exponentially with height into the more rarified atmosphere where they dissipate, deposit net momentum and heat, and induce net constituent transport. Some waves penetrate to the base of the exosphere (ca. 500-600 km). Over the past decade, a mature knowledge of the tidal part of the spectrum has emerged, in an average or climatological sense, up to about 110 km. This knowledge has largely accrued as a result of remote sensing observations made from the TIMED satellite. These observations have also enabled limited studies on day-to-day variability of atmospheric tides, the PW and Kelvin wave spectra up to 110 km, and PW-tide coupling. Complementary ionospheric observations made by GPS receivers, COSMIC, CHAMP, and ROCSAT contain signatures of plasma redistributions induced by these waves, and ionosphere-thermosphere (IT) general circulation models have been developed that provide a corroborating theoretical foundation. Pioneering theoretical and modeling work also demonstrate the importance of the GW part of the spectrum on thermosphere circulation and thermal structure. While significant strides have been made, critical shortcomings in our understanding of atmosphere-IT coupling remain. In particular, we are practically absent any observations of the vertical evolution and dissipation of the wave spectrum between 100 and 200 km, which is also the region where electric fields and currents are generated by dynamo action. Moreover, the day-to-day variability of the wave spectrum and secondary wave generation remain to be quantified in this critical region. In this talk, the above progress and knowledge gaps will be examined in light of imminent and potential future missions.

Climatology of GW-TIDs in the magnetic equatorial upper thermosphere over India

NASA Astrophysics Data System (ADS)

Manju, G.; Aswathy, R. P.

2017-11-01

An analysis of Gravity wave induced travelling ionospheric disturbances (GW-TIDs) in the thermosphere during high and low solar epochs is undertaken using ionosonde data at Trivandrum (8.50N, 770E). Wavelet analysis is performed on the temporal variations of foF2 and the amplitudes of waves present in two period bands of (0.5-1.5) h and (2-4) h are extracted. The real height profiles are generated at 15 min internal for the whole day (for sample days) during high and low solar activity years. The study reveals that the GW-TID activity is significantly greater for solar minimum compared to solar maximum for the period 8.5-17.5 h. Diurnally the GW-TID activity in the (2-4) h period band peaks in the post sunset hours for both high and low solar epochs. For the 0.5-1.5 h period band, the diurnal maximum in GW-TID is occurring in the post sunset hours for high solar epoch while it occurs in the morning hours around 10 h LT for low solar epoch. Seasonally the day time GW-TID activity maximizes (minimizes) for winter (vernal equinox). The post sunset time GW-TID maximizes (minimizes) either for summer/winter (vernal equinox). The other interesting observation is the anti correlation of GW-TID in upper thermosphere with solar activity for day time and the correlation of the same with solar activity in the post sunset hours. The present results for daytime are in agreement with the equatorial daytime GW-TID behaviour reported from CHAMP satellite observations. The GW-TID activity during post sunset time for equatorial region upper thermosphere has not been reported so far.

Testing of Selected Geopotential Models in Terms of GOCE Satellite Orbit Determination Using Simulated GPS Observations

NASA Astrophysics Data System (ADS)

Bobojc, Andrzej; Drozyner, Andrzej

2016-04-01

This work contains a comparative study of performance of twenty geopotential models in an orbit estimation process of the satellite of the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) mission. For testing, among others, such models as JYY_GOCE02S, ITG-GOCE02, ULUX_CHAMP2013S, GOGRA02S, ITG-GRACE2010S, EIGEN-51C, EGM2008, EGM96, JGM3, OSU91a, OSU86F were adopted. A special software package, called the Orbital Computation System (OCS), based on the classical method of least squares was used. In the frame of OCS, initial satellite state vector components are corrected in an iterative process, using the given geopotential model and the models describing the remaining gravitational perturbations. An important part of the OCS package is the 8th order Cowell numerical integration procedure, which enables a satellite orbit computation. Different sets of pseudorange simulations along reference GOCE satellite orbital arcs were obtained using real orbits of the Global Positioning System (GPS) satellites. These sets were the basic observation data used in the adjustment. The centimeter-accuracy Precise Science Orbit (PSO) for the GOCE satellite provided by the European Space Agency (ESA) was adopted as the GOCE reference orbit. Comparing various variants of the orbital solutions, the relative accuracy of geopotential models in an orbital aspect is determined. Full geopotential models were used in the adjustment process. However, the solutions were also determined taking into account truncated geopotential models. In such case, an accuracy of the orbit estimated was slightly enhanced. The obtained solutions refer to the orbital arcs with the lengths of 90-minute and 1-day.

Computational Analysis of Artificial Gravity as a Possible Countermeasure to Spaceflight Induced Bone Loss

NASA Technical Reports Server (NTRS)

Mulugeta, L.; Werner, C. R.; Pennline, J. A.

2015-01-01

During exploration class missions, such as to asteroids and Mars, astronauts will be exposed to reduced gravity for extended periods. Data has shown that astronauts lose bone mass at a rate of 1% to 2% a month in microgravity, particularly in lower extremities such as the proximal femur. Exercise countermeasures have not completely eliminated bone loss from long duration spaceflight missions, which leaves astronauts susceptible to early onset osteoporosis and greater risk of fracture. Introduction of the Advanced Resistive Exercise Device and other large exercise devices on the International Space Station (ISS), coupled with improved nutrition, has further minimized bone loss. However, unlike the ISS, exploration vehicles will have very limited volume and power available to accommodate such capabilities. Therefore, novel concepts like artificial gravity systems are being explored as a means to provide sufficient load stimulus to the musculoskeletal system to mitigate bone changes that may lead to early onset osteoporosis and increased risk of fracture. Currently, there is minimal data available to drive further research and development efforts to appropriately explore such options. Computational modeling can be leveraged to gain insight on the level of osteoprotection that may be achieved using artificial gravity produced by a spinning spacecraft or centrifuge. With this in mind, NASA's Digital Astronaut Project (DAP) has developed a bone remodeling model that has been validated for predicting volumetric bone mineral density (vBMD) changes of trabecular and cortical bone both for gravitational unloading condition and the equivalent of 1g daily load stimulus. Using this model, it is possible to simulate vBMD changes in trabecular and cortical bone under different gravity conditions. In this presentation, we will discuss our preliminary findings regarding if and how artificial gravity may be used to mitigate spaceflight induced bone loss.

The gravity field and orientation of Mercury after the MESSENGER mission

NASA Astrophysics Data System (ADS)

Mazarico, E.; Genova, A.; Goossens, S. J.; Lemoine, F. G.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.; Solomon, S. C.

2015-12-01

After more than four years in orbit about Mercury, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft impacted the planet's surface north of Shakespeare crater (54.44° N, 210.12° E,) on 30 April 2015. One of the main goals of the mission was to determine the gravity field of Mercury in order to learn about Mercury's interior. Together with ground-based radar measurements of the obliquity and forced librations, MESSENGER-derived gravity models helped revise models of Mercury's interior. Nevertheless, the refinement of Mercury's orientation with the latest data from MESSENGER can further improve the interior modeling of the planet. The last eight months of the mission provided a special opportunity to conduct low-altitude measurements, with extensive radio tracking coverage below 200 km altitude north of ~30°N. MESSENGER's Mercury Laser Altimeter (MLA) mapped the topography of Mercury's northern hemisphere with a sub-meter vertical precision, an along-track sampling of ~500 m, and a longitudinal resolution (~0.1°) limited by the number of spacecraft orbits (~4,000). The combination of gravity and topography helps determine crustal thickness and interior properties. Altimetric ranges provide geodetic constraints to improve the spacecraft orbit determination, and thus the gravity field model. In particular, whereas the MESSENGER spacecraft was not tracked at each periapsis passage, MLA operated nearly continuously (outside of thermally challenging periods). From an analysis of the entire radiometric and altimetric datasets acquired by MESSENGER, a new gravity field to degree and order 100 has been obtained, resolving features down to ~75 km horizontal scale. The altimetric data help reduce the uncertainties in the determination of the pole position. A reanalysis of the Mercury flybys also constrains the spin rate over the longest available time span.

A pilot study to assess if urine specific gravity and urine colour charts are useful indicators of dehydration in acute stroke patients.

PubMed

Rowat, Anne; Smith, Laura; Graham, Cat; Lyle, Dawn; Horsburgh, Dorothy; Dennis, Martin

2011-09-01

The purpose of this pilot study was to examine whether urine specific gravity and urine colour could provide an early warning of dehydration in stroke patients compared with standard blood indicators of hydration status. Dehydration after stroke has been associated with increased blood viscosity, venous thrombo-embolism and stroke mortality at 3-months. Earlier identification of dehydration might allow us to intervene to prevent significant dehydration developing or reduce its duration to improve patient outcomes. We recruited 20 stroke patients in 2007 and measured their urine specific gravity with urine test strips, a refractometer, and urine colour of specimens taken daily on 10 consecutive days and compared with the routine blood urea:creatinine ratios over the same period to look for trends and relationships over time. The agreement between the refractometer, test strips and urine colour were expressed as a percentage with 95% confidence intervals. Nine (45%) of the 20 stroke patients had clinical signs of dehydration and had a significantly higher admission median urea:creatinine ratio (P = 0·02, Mann-Whitney U-test). There were no obvious relationships between urine specific gravity and urine colour with the urea:creatinine ratio. Of the 174 urine samples collected, the refractometer agreed with 70/174 (40%) urine test strip urine specific gravity and 117/174 (67%) urine colour measurements. Our results do not support the use of the urine test strip urine specific gravity as an early indicator of dehydration. Further research is required to develop a practical tool for the early detection of dehydration in stroke patients. © 2011 Blackwell Publishing Ltd.

ITSG-Grace2016 data preprocessing methodologies revisited: impact of using Level-1A data products

NASA Astrophysics Data System (ADS)

Klinger, Beate; Mayer-Gürr, Torsten

2017-04-01

For the ITSG-Grace2016 release, the gravity field recovery is based on the use of official GRACE (Gravity Recovery and Climate Experiment) Level-1B data products, generated by the Jet Propulsion Laboratory (JPL). Before gravity field recovery, the Level-1B instrument data are preprocessed. This data preprocessing step includes the combination of Level-1B star camera (SCA1B) and angular acceleration (ACC1B) data for an improved attitude determination (sensor fusion), instrument data screening and ACC1B data calibration. Based on a Level-1A test dataset, provided for individual month throughout the GRACE period by the Center of Space Research at the University of Texas at Austin (UTCSR), the impact of using Level-1A instead of Level-1B data products within the ITSG-Grace2016 processing chain is analyzed. We discuss (1) the attitude determination through an optimal combination of SCA1A and ACC1A data using our sensor fusion approach, (2) the impact of the new attitude product on temporal gravity field solutions, and (3) possible benefits of using Level-1A data for instrument data screening and calibration. As the GRACE mission is currently reaching its end-of-life, the presented work aims not only at a better understanding of GRACE science data to reduce the impact of possible error sources on the gravity field recovery, but it also aims at preparing Level-1A data handling capabilities for the GRACE Follow-On mission.

Annual, Seasonal, and Secular Changes in Time-Variable Gravity from GRACE

NASA Astrophysics Data System (ADS)

Lemoine, F. G.; Luthcke, S. B.; Klosko, S. M.; Rowlands, D. D.; Chinn, D. S.; McCarthy, J. J.; Ray, R. D.; Boy, J.

2007-12-01

The NASA/DLR GRACE mission, launched in 2002, has now operated for more than five years, producing monthly and ten-day snapshots of the variations of the gravity field of the Earth. The available solutions, either from spherical harmonics or from mascons, allow us new insights into the variations of surface gravity on the Earth at annual, inter-annual, and secular time scales. Our baseline time series, based on GGM02C, NCEP Atmospheric Gravity with IB, and GOT00 tides now is extended to July 2007, spanning four+ years, and we analyze both mascon and spherical harmonic solutions from this time series with respect to global hydrology variations. Our 4degx4deg mascon solutions are extended to cover all continental regions of the globe. Comparisons with hydrology (land-surface) models can offer insights into how these models might be improved. We compare our baseline time series, with new time series that include an updated Goddard Ocean Tide (GOT) model, ECMWF- 3hr atmosphere de-aliasing data, and the MOG-2D ocean dealiasing product. Finally, we intercompare the spherical harmonic solutions at low degree from GRACE from the various product centers (e.g., GFZ, CSR, GRGS), and look for secular signals in both the GSFC mascon and spherical harmonic solutions, taking care to compare the results for secular gravity field change with independent solutions developed over 25 years of independent tracking to geodetic satellites by Satellite Laser Ranging (SLR) and DORIS.

Land Water Storage within the Congo Basin Inferred from GRACE Satellite Gravity Data

NASA Technical Reports Server (NTRS)

Crowley, John W.; Mitrovica, Jerry X.; Bailey, Richard C.; Tamisiea, Mark E.; Davis, James L.

2006-01-01

GRACE satellite gravity data is used to estimate terrestrial (surface plus ground) water storage within the Congo Basin in Africa for the period of April, 2002 - May, 2006. These estimates exhibit significant seasonal (30 +/- 6 mm of equivalent water thickness) and long-term trends, the latter yielding a total loss of approximately 280 km(exp 3) of water over the 50-month span of data. We also combine GRACE and precipitation data set (CMAP, TRMM) to explore the relative contributions of the source term to the seasonal hydrological balance within the Congo Basin. We find that the seasonal water storage tends to saturate for anomalies greater than 30-44 mm of equivalent water thickness. Furthermore, precipitation contributed roughly three times the peak water storage after anomalously rainy seasons, in early 2003 and 2005, implying an approximately 60-70% loss from runoff and evapotranspiration. Finally, a comparison of residual land water storage (monthly estimates minus best-fitting trends) in the Congo and Amazon Basins shows an anticorrelation, in agreement with the 'see-saw' variability inferred by others from runoff data.

Gravity, Body Mass and Composition, and Metabolic Rate

NASA Technical Reports Server (NTRS)

Pace, N.; Smith, A. H.

1985-01-01

Metabolic rate and body composition as a function of sex and age were defined in 5 species of common laboratory mammals, the mouse, hamster, rat, guinea pig and rabbit. Oxygen consumption and carbon dioxide production rates were measured individually in 6 male and 6 female animals for each of 8 age cohorts ranging from 1 month to 2 years, and for each of the species. From the results it is evident that among these small mammals there is no indication of scaling of muscularity to body size, despite the 100-fold difference in body mass represented by the skeletal musculature seems to reach a pronounced peak value at age 2 to 3 months and then declines, the fraction of the fat-free body represented by other body components in older animals must increase complementarily. Under normal gravity conditions muscularity in small laboratory mammals displays large, systematic variation as a function both of species and age. This variation must be considered when such animals are subjects of experiments to study the effects of altered gravitational loading on the skeletal musculature of the mammal.

Hydrology Applications of the GRACE missions

NASA Astrophysics Data System (ADS)

Srinivasan, M. M.; Ivins, E. R.; Jasinski, M. F.

2014-12-01

NASA and their German space agency partners have a rich history of global gravity observations beginning with the launch of the Gravity Recovery And Climate Experiment (GRACE) in 2002. The science goals of the mission include providing monthly maps of variations in the gravity field, where the major time-varying signal is due to water motion in the Earth system. GRACE has a unique ability to observe the mass flux of water movement at monthly time scales. The hydrology applications of the GRACE mission include measurements of seasonal storage of surface and subsurface water and evapotranspiration at the land-ocean-atmosphere boundary. These variables are invaluable for improved modeling and prediction of Earth system processes. Other mission-critical science objectives include measurements that are a key component of NASA's ongoing climate measuring capabilities. Successful strategies to enhance science and practical applications of the proposed GRACE-Follow On (GRACE-FO) mission, scheduled to launch in 2017, will require engaging with and facilitating between representatives in the science, societal applications, and mission planning communities. NASA's Applied Sciences Program is supporting collaboration on an applied approach to identifying communities of potential and of practice in order to identify and promote the societal benefits of these and future gravity missions. The objective is to engage applications-oriented users and organizations and enable them to envision possible applications and end-user needs as a way to increase the benefits of these missions to the nations. The focus of activities for this applications program include; engaging the science community in order to identify applications and current and potential data users, developing a written Applications Plan, conducting workshops and user tutorials, providing ready access to information via web pages, developing databases of key and interested users/scientists, creating printed materials (posters, brochures) that identify key capabilities and applications of the missions and data, and participation in key science meetings and decision support processes.

Crew Health and Performance on Mars

NASA Technical Reports Server (NTRS)

Stegemoeller, Charlie

1998-01-01

The issues surrounding the health and performance on Mars of a human crew are discussed in this presentation. The work of Human Space Life Sciences Program Office (HSLSPO) in the preparation of a crew for a Martian mission is reviewed. This includes a review of issues relating to human health and performance (HHP) in space and microgravity. The Mars design reference mission requires the most rigorous life sciences critical path of any manned mission in the forseeable future. This mission will require a 30 months round trip, with 4 different transistions to different gravities, and two episodes of high gravity load, during the Mars and Earth Aerobraking exercises. A graph is presented which shows the number of subjects with human space flight experience greater than 30 days. A chart presents the physical challenges to HHP in terms of gravity and acceleration and the length of times the crew will be exposed to the various gravity loads. Another chart presents the radiation challenges to the HHP for the duration of the trip. The human element is the most complex element of the mission design. Some challenges (i.e., human engineering and life support) must be overcome, and some issues such as bone loss, and radiation exposure must be addressed prior to making a decision for a manned Martian mission.

Determination of specific yield and water-table changes using temporal microgravity surveys collected during the second injection, storage, and recovery test at Lancaster, Antelope Valley, California, November 1996 through April 1997

USGS Publications Warehouse

Howle, James F.; Phillips, Steven P.; Denlinger, Roger P.; Metzger, Loren F.

2003-01-01

To evaluate the feasibility of artificially recharging the ground-water system in the Lancaster area of the Antelope Valley, California, the U.S. Geological Survey, in cooperation with the Los Angeles County Department of Public Works and the Antelope Valley-East Kern Water Agency, conducted a series of injection, storage, and recovery tests between September 1995 and September 1998. A key component of this study was to measure the response of the water table to injection, which was difficult because the water table averaged 300 feet below land surface. Rather than install many expensive piezometers, microgravity surveys were conducted to determine specific yield and to measure the development of a ground-water mound during the injection of about 1,050 acre-feet of fresh water into an alluvial-aquifer system. The surveys were done prior to, during, and near the end of a 5-month injection period (November 12, 1996, to April 17, 1997). Results of the surveys indicate increases in gravity of as much as 66 microgals between a bedrock reference station and 20 gravity stations within a 1-square-mile area surrounding the injection site. The changes were assumed to have been caused by changes in the ground-water elevation. Gravity and ground-water levels were measured simultaneously at an existing well (7N/12W-34B1). The coupled measurements were used to calculate a specific yield of 0.13 for the alluvial aquifer near the well. To determine the gravitational effect of the injection mound on the gravity measurements made near well 7N/12W-34B1, a two-dimensional gravity model was used. Results of the model simulation show that the effect on gravity associated with the mass of the injection mound was minor and thus had a negligible effect on the calculation of specific yield. The specific yield of 0.13, therefore, was used to infer water-level changes at other gravity stations within the study area. The gravity-derived water-level changes were compared with simulated water-table changes.

Statistical Characterization of MP3 Encoders for Steganalysis: ’CHAMP3’

DTIC Science & Technology

2004-04-27

compression exceeds those of typical stegano- graphic tools (e. g., LSB image embedding), the availability of commented source codes for MP3 encoders...developed by testing the approach on known and unknown reference data. 15. SUBJECT TERMS EOARD, Steganography , Digital Watermarking...Pages kbps Kilobits per Second LGPL Lesser General Public License LSB Least Significant Bit MB Megabyte MDCT Modified Discrete Cosine Transformation MP3

Physics of the Geospace Response to Powerful HF Radio Waves

DTIC Science & Technology

2012-10-31

studies of the response of the Earth’s space plasma to high-power HF radio waves from the High-frequency Active Auroral Research Program ( HAARP ...of HF heating and explored to simulate artificial ducts. DMSP- HAARP experiments revealed that HF-created ion outflows and artificial density ducts...in the topside ionosphere appeared faster than predicted by the models, pointing to kinetic (suprathermal) effects. CHAMP/GRACE- HAARP experiments

Stull Repeats as Chili Champ | Poster

Cancer.gov

By Ken Michaels, Staff Writer Jim Stull, winner of the ninth annual Protective Services Chili Cookoff in January of last year, proved that he’s no one-trick pony; he brought a brand new recipe to the 2013 event and won again! And he did it decisively. His Black Bean ‘n Pumpkin Chili garnered 107 points; the second place winner netted less than half that with 52. “For me, a

ARC-2009-ACD09-0150-003

NASA Image and Video Library

2009-07-22

Timothy Collins, President and Chairman, KleenSpeed Technologies, Inc. and Captain Andrew Butte, rescue helicopter pilot and former Army Aviator, with Butte's 1999 SWIFT. ChampCar Butte has given his racecar to KleenSpeed for conversion to electric. KleenSpeed is an advanced R&D firm focusing on scalable electric propulsion systems for transportation. The company is based at the NASA Research Park (NRP) Moffett Field, California as a lease holder.

Oscillator strengths of the optical transitions in a semiconductor superlattice under an electric field

NASA Astrophysics Data System (ADS)

Tronc, P.

1992-04-01

The oscillator strengths of the optical transitions in a semiconductor superlattice under an electric field parallel to the growth axis can be calculated using a perturbative model with Bloch envelope functions. The applied electric field and the electron-hole interaction inducing formation of indirect excitons both induce strength asymmetry between the oblique +p and -p transitions of the Wannier-Stark ladder. Features of the photocurrent spectra recorded at low temperature can be accounted for by the present model in a very simple manner. Les forces d'oscillateur des transitions optiques dans un superréseau semiconducteur soumis à un champ électrique parallèle à la direction de croissance, peuvent être calculées à l'aide d'un modèle de perturbation avec des fonctions enveloppes de Bloch. Le champ électrique appliqué ainsi que l'interaction électron-trou, qui induit la formation d'excitons indirects, entraînent une asymétrie entre les forces d'oscillateur des transitions +p et -p dans l'échelle de Wannier-Stark. Certaines caractéristiques des spectres de photocourant enregistrés à basse température peuvent être prévues d'une manière très simple.

The influence of anthropometry and body composition on children's bone health: the childhood health, activity and motor performance school (the CHAMPS) study, Denmark.

PubMed

Heidemann, Malene; Holst, René; Schou, Anders J; Klakk, Heidi; Husby, Steffen; Wedderkopp, Niels; Mølgaard, Christian

2015-02-01

Overweight, physical inactivity and sedentary behaviour have become increasing problems during the past decade. Increased sedentary behaviour may change the body composition (BC) by increasing the fat mass relative to the lean mass (LM). These changes may influence bone health to describe how anthropometry and BC predict the development of the bone accruement. The longitudinal study is a part of The CHAMPS study-DK. Children were DXA scanned at baseline and at 2-year follow-up. BC (LM, BF %) and BMC, BMD and BA were measured. The relationship between bone traits, anthropometry and BC was analysed by multilevel regression analyses. Of the invited children, 742/800 (93%) accepted to participate. Of these, 682/742 (92%) participated at follow-up. Mean (range) of age at baseline was 9.5 years (7.7-12.1). Height, BMI, LM and BF % predicted bone mineral accrual and bone size positively and independently. Height and BMI are both positive predictors of bone accruement. LM is a more precise predictor of bone traits than BF % in both genders. The effects of height and BMI and LM on bone accruement are nearly identical in the two genders, while changes in BF % have different but positive effects on bone accretion in both boys and girls.

A southern Africa harmonic spline core field model derived from CHAMP satellite data

NASA Astrophysics Data System (ADS)

Nahayo, E.; Kotzé, P. B.; McCreadie, H.

2015-02-01

The monitoring of the Earth's magnetic field time variation requires a continuous recording of geomagnetic data with a good spatial coverage over the area of study. In southern Africa, ground recording stations are limited and the use of satellite data is needed for the studies where high spatial resolution data is required. We show the fast time variation of the geomagnetic field in the southern Africa region by deriving an harmonic spline model from CHAMP satellite measurements recorded between 2001 and 2010. The derived core field model, the Southern Africa Regional Model (SARM), is compared with the global model GRIMM-2 and the ground based data recorded at Hermanus magnetic observatory (HER) in South Africa and Tsumeb magnetic observatory (TSU) in Namibia where the focus is mainly on the long term variation of the geomagnetic field. The results of this study suggest that the regional model derived from the satellite data alone can be used to study the small scale features of the time variation of the geomagnetic field where ground data is not available. In addition, these results also support the earlier findings of the occurrence of a 2007 magnetic jerk and rapid secular variation fluctuations of 2003 and 2004 in the region.

An algorithm for deriving core magnetic field models from the Swarm data set

NASA Astrophysics Data System (ADS)

Rother, Martin; Lesur, Vincent; Schachtschneider, Reyko

2013-11-01

In view of an optimal exploitation of the Swarm data set, we have prepared and tested software dedicated to the determination of accurate core magnetic field models and of the Euler angles between the magnetic sensors and the satellite reference frame. The dedicated core field model estimation is derived directly from the GFZ Reference Internal Magnetic Model (GRIMM) inversion and modeling family. The data selection techniques and the model parameterizations are similar to what were used for the derivation of the second (Lesur et al., 2010) and third versions of GRIMM, although the usage of observatory data is not planned in the framework of the application to Swarm. The regularization technique applied during the inversion process smoothes the magnetic field model in time. The algorithm to estimate the Euler angles is also derived from the CHAMP studies. The inversion scheme includes Euler angle determination with a quaternion representation for describing the rotations. It has been built to handle possible weak time variations of these angles. The modeling approach and software have been initially validated on a simple, noise-free, synthetic data set and on CHAMP vector magnetic field measurements. We present results of test runs applied to the synthetic Swarm test data set.

KSC-03PD-2754

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. In the spacecraft processing facility on North Vandenberg Air Force Base, workers conduct battery charge/discharge cycles as part of the battery conditioning process on Gravity Probe B. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2751

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. In the spacecraft processing facility on North Vandenberg Air Force Base, workers conduct battery charge/discharge cycles as part of the battery conditioning process on Gravity Probe B. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2752

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. In the spacecraft processing facility on North Vandenberg Air Force Base, workers conduct battery charge/discharge cycles as part of the battery conditioning process on Gravity Probe B. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2750

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. In the spacecraft processing facility on North Vandenberg Air Force Base, battery charge/discharge cycles are underway as part of the battery conditioning process on Gravity Probe B. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2753

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. In the spacecraft processing facility on North Vandenberg Air Force Base, workers conduct battery charge/discharge cycles as part of the battery conditioning process on Gravity Probe B. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03pd2743

NASA Image and Video Library

2003-07-11

VANDENBERG AFB, CALIF. - Enclosed in a canister, the Gravity Probe B (GP-B) spacecraft arrives at the spacecraft processing facility on North Vandenberg Air Force Base . Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einstein’s general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it). Once in orbit, for 18 months each gyroscope’s spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASA’s Marshall Space Flight Center.

KSC-2011-6513

NASA Image and Video Library

2011-08-18

CAPE CANAVERAL, Fla. -- Technicians lower NASA's twin Gravity Recovery and Interior Laboratory (GRAIL) spacecraft into place atop a United Launch Alliance Delta II rocket on Space Launch Complex 17B at Cape Canaveral Air Force Station in Florida. The lunar probes are attached to a spacecraft adapter ring in their side-by-side launch configuration and wrapped in plastic to prevent contamination outside the clean room. The spacecraft will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch is scheduled for Sept. 8. For more information, visit www.nasa.gov/grail. Photo credit: NASA/Kim Shiflett

KSC-2011-6103

NASA Image and Video Library

2011-07-30

CAPE CANAVERAL, Fla. -- Preparations are under way to begin two days of fueling activities on NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft in the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Charisse Nahser

KSC-03PD-2868

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. A worker in the spacecraft processing facility on North Vandenberg Air Force Base checks the Gravity Probe B experiment during prelaunch testing. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

Navigation of the Twin GRAIL Spacecraft into Science Formation at the Moon

NASA Technical Reports Server (NTRS)

Antreasian, P. G.; Bhat, R. S.; Criddle, K. E.; Goodson, T. D.; Hatch, S. J; Jefferson, D. C.; Lau, E. L.; Mohan, S.; Parker, J. S.; Roncoli, R. B.;

Tide Gauge Records Reveal Improved Processing of Gravity Recovery and Climate Experiment Time-Variable Mass Solutions over the Coastal Ocean

NASA Astrophysics Data System (ADS)

Piecuch, Christopher G.; Landerer, Felix W.; Ponte, Rui M.

2018-05-01

Monthly ocean bottom pressure solutions from the Gravity Recovery and Climate Experiment (GRACE), derived using surface spherical cap mass concentration (MC) blocks and spherical harmonics (SH) basis functions, are compared to tide gauge (TG) monthly averaged sea level data over 2003-2015 to evaluate improved gravimetric data processing methods near the coast. MC solutions can explain ≳ 42% of the monthly variance in TG time series over broad shelf regions and in semi-enclosed marginal seas. MC solutions also generally explain ˜5-32 % more TG data variance than SH estimates. Applying a coastline resolution improvement algorithm in the GRACE data processing leads to ˜ 31% more variance in TG records explained by the MC solution on average compared to not using this algorithm. Synthetic observations sampled from an ocean general circulation model exhibit similar patterns of correspondence between modeled TG and MC time series and differences between MC and SH time series in terms of their relationship with TG time series, suggesting that observational results here are generally consistent with expectations from ocean dynamics. This work demonstrates the improved quality of recent MC solutions compared to earlier SH estimates over the coastal ocean, and suggests that the MC solutions could be a useful tool for understanding contemporary coastal sea level variability and change.

VLTI: First Light for the Second Generation

NASA Astrophysics Data System (ADS)

Woillez, J.; Gonté, F.; Abad, J. A.; Abadie, S.; Abuter, R.; Accardo, M.; Acuña, M.; Alonso, J.; Andolfato, L.; Avila, G.; Barriga, P. J.; Beltran, J.; Berger, J.-P.; Bollados, C.; Bourget, P.; Brast, R.; Bristow, P.; Caniguante, L.; Castillo, R.; Conzelmann, R.; Cortes, A.; Delplancke, F.; Dell Valle, D.; Derie, F.; Diaz, A.; Donoso, R.; Duhoux, Ph.; Dupuy, C.; Elao, C.; Egner, S.; Fuenteseca, E.; Fernandez, R.; Gaytan, D.; Glindemann, A.; Gonzales, J.; Guisard, S.; Hagenauer, P.; Haimerl, A.; Heinz, V.; Henriquez, J. P.; van der Heyden, P.; Hubin, N.; Huerta, R.; Jochum, L.; Kirchbauer, J.-P.; Leiva, A.; Lévêque, S.; Lizon, J.-P.; Luco, F.; Mardones, P.; Mellado, A.; Mérand, A.; Osorio, J.; Ott, J.; Pallanca, L.; Pavez, M.; Pasquini, L.; Percheron, I.; Pirard, J.-F.; Phan, D. T.; Pineda, J. C.; Pino, A.; Poupar, S.; Ramírez, A.; Reinero, C.; Riquelme, M.; Romero, J.; Rivinius, Th.; Rojas, C.; Rozas, F.; Salgado, F.; Schöller, M.; Schuhler, N.; Siclari, W.; Stephan, C.; Tamblay, R.; Tapia, M.; Tristram, K.; Valdes, G.; de Wit, W.-J.; Wright, A.; Zins, G.

2015-12-01

The Very Large Telescope Interferometer (VLTI) stopped operation on 4 March 2015 with the objective of upgrading its infrastructure in preparation for the second generation VLTI instruments GRAVITY and MATISSE. A brief account of the eight bustling months it took our interferometer to metamorphose into its second generation, under the supervision of the VLTI Facility Project, is presented.

New insights into ocean tide loading corrections on tidal gravity data in Canary Islands

NASA Astrophysics Data System (ADS)

Arnoso, J.; Benavent, M.; Bos, M. S.; Montesinos, F. G.

2009-04-01

The Canary Islands are an interesting area to investigate ocean tides loading effects due to the complex coastline of the islands and the varying bathymetry. We present here the quality of five recent global oceanic tidal models, GOT00.2, GOT4.7, FES2004, TPXO.7.1 and AG2006, by comparing their predicted ocean tide loading values with results from tidal gravity observations made on three islands, Lanzarote, Tenerife and El Hierro, for the four harmonic constituents O1, K1, M2 and S2. In order to improve the accuracy of the loading corrections on the gravity tide measurements, we have used the high resolution regional oceanic model CIAM2 to supplement the global models considered here. This regional model has been obtained by assimilating TOPEX/Poseidon altimetry at crossovers and along-track points and tide gauge observations into a hydrodynamic model. The model has a 5'Ã-5' resolution and covers the area between the coordinates 26°.5N to 30°.0N and 19°.0W to 12°.5W. The gravity tide observing sites have been occupied by three different LaCoste&Romberg (LCR) spring gravimeters during different periods of observation. We considered here the most recent gravity tide observations made with LCR Graviton-EG1194 in El Hierro Island, for a period of 6 months during 2008. In the case of Tenerife and Lanzarote sites we have used observation periods of 6 months and 8 years with LCR-G665 and LCR-G434 gravimeters, respectively. The last two sites have been revisited in order to improve the previous tidal analysis results. Thus, the gravity ocean tide loading corrections, based on the five global ocean tide models supplemented with the regional model CIAM2 allowed us to review the normalization factors (scale factor and phase lag) of both two gravimeters. Also, we investigated the discrepancies of the corrected gravimetric factors with the DDW elastic and inelastic non hydrostatic body tide model (Dehant et al., 1999). The lowest values are found for inelastic model in the case of M2 and O1 waves at three sites. However, the scatter between oceanic models seen at final residual vectors does not indicate clearly if tidal observations are close to elastic or inelastic body tide model. Finally, after computing misfits of gravity tide observations and ocean tide loading calculations the level of agreement between the five global oceanic models is below 0.2 Gal (1 Gal=10-8ms-2), except for the solar harmonic K1, which reaches a large value that reflects the thermal instability at three sites because the period of K1 is very close to that of S1. None of the five global models seems to give results that are clearly better than the other models.

Impact of a Community-Based Programme for Motor Development on Gross Motor Skills and Cognitive Function in Preschool Children from Disadvantaged Settings

ERIC Educational Resources Information Center

Draper, Catherine E.; Achmat, Masturah; Forbes, Jared; Lambert, Estelle V.

2012-01-01

The aims of the studies were to assess the impact of the Little Champs programme for motor development on (1) the gross motor skills, and (2) cognitive function of children in the programme. In study 1, 118 children from one Early Childhood Development Centre (ECDC) were tested using the Test of Gross Motor Development-2, and in study 2, 83…

10. VIEW OF BASEMENT, LOOKING NORTHEAST. AT LEFT CENTER IS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. VIEW OF BASEMENT, LOOKING NORTHEAST. AT LEFT CENTER IS A 'BISON' CORN CRACKER (Wolf Co., Champ, Pennsylvania), DESIGNED TO CRACK KERNEL CORN. AT LEFT IS A 'EUREKA' CLEANER (S. Howe Co., Silver Creek, New York), WHOSE RECIPROCATING SIEVES REMOVED COARSE FOREIGN MATERIAL FROM WHEAT BEFORE MAKING FLOUR. Photographer: Jet T. Lowe, 1985 - Alexander's Grist Mill, Lock 37 on Ohio & Erie Canal, South of Cleveland, Valley View, Cuyahoga County, OH

Prediction of Aerodynamic Loads on Rotorcraft.

DTIC Science & Technology

1982-09-01

CALCULATION ON HORIZONTAL AXIS WIND TURBINE IN NON UNIFORM FLOW by E.Lupo 6 PREDICTION ET VERIFICATION EXPERIMENTALE DU CHAMP DES VITESSES D’UN ROTOR...calculs, do plus en plus sophistiqugs, tridimensionnols quasi -stationnairos ou instationnaires non portants ou portents, mime our pale isolfe do rotor...exemple d’dquations de Ia mdcanique des pales. Ces 6quationa sont quasi lin~aires en fonc- tion des portances mgme non lindaires. L’a6rodynamique examinde

Evaluation of the Impacts of Live Fire Training at CFB Shilo

DTIC Science & Technology

2003-04-22

des activites d’entrainement faites au secteur d’entrainement de la BFC Shilo et est la suite de la phase I, effectuee en septembre 2000. Durant la...premiere phase, trois champs de bataille avaient ete echantillonnes pour evaluer la contamination par les explosifs, les metaux, les COVs et les...iv Sommaire Le contexte international de demilitarisation, de la fermeture de bases et de la severite croissante des lois environnementales a

Adapting to wildfire: Moving beyond homeowner risk perceptions to taking action

Treesearch

Patricia Champ

2017-01-01

Champ’s presentation focused on how to get homeowners to take action to protect their properties from fire. She framed this challenge as a last-mile problem, which is a concept from the literature on supply chain. The last mile is the end of the supply chain where a product is transferred to the customer. The last mile is often the most difficult part of the entire...

A SmallSat constellation mission architecture for a GRACE-type mission design

NASA Astrophysics Data System (ADS)

Deccia, C. M. A.; Nerem, R. S.; Yunck, T.

2017-12-01

The Gravity Recovery and Climate Experiment (GRACE) launched in 2002 and has been providing invaluable information of Earth's time-varying gravity field and GRACE-FO will continue this time series. For this work, we focus on architectures of future post-GRACE-FO like missions. Single pairs of satellites like GRACE and GRACE-FO are inherently limited in their spatio-temporal coverage. Full global coverage for a single pair can take up to 30 days for spatial resolutions of a few hundred kilometers, thus a single satellite pair is unable to observe sub-monthly signals in the Earth's time varying gravity field (e.g. hydrologic signals, etc.). Small satellite systems are becoming increasingly affordable and will soon allow a constellation of GRACE-type satellites to be deployed, with the capability to range between multiple satellites. Here, using simulation studies, we investigate the performance of such a constellation for different numbers of satellites (N) and different orbital configurations, in order to understand the improved performance that might be gained from such future mission architectures.

Intraseasonal to interannual variations in the tropical wave activity revealed in reanalyses and their potential impact on the QBO

NASA Astrophysics Data System (ADS)

Kim, Young-Ha; Yoo, Changhyun

2017-04-01

We investigate activities of tropical waves represented in reanalysis products. The wave activities are quantified by the Eliassen-Palm (EP) flux at 100 hPa, after decomposed into the following four components: equatorially trapped Kelvin waves and mixed Rossby-gravity waves, gravity waves, and Rossby waves. Monthly EP fluxes of the four waves exhibit considerable temporal variations at intraseasonal and interannual, along with seasonal, time scales. These variations are discussed with the tropical large-scale variabilities, including the Madden-Julian Oscillation (MJO), the El Ninõ-Southern Oscillation, and the stratospheric quasi-biennial oscillation (QBO). We find that during boreal winter, the interannual variation of Kelvin wave activity is in phase with that of the MJO amplitude, while such a simultaneous variation cannot be seen in other seasons. The gravity wave is dominated by a semi-annual cycle, while the departure from its semi-annual cycle is largely correlated with the QBO phase in the stratosphere. Potential impacts of the variations in the wave activity upon the QBO properties will be assessed using a simple one-dimensional QBO model.

Vecteurs Singuliers des Theories des Champs Conformes Minimales

NASA Astrophysics Data System (ADS)

Benoit, Louis

En 1984 Belavin, Polyakov et Zamolodchikov revolutionnent la theorie des champs en explicitant une nouvelle gamme de theories, les theories quantiques des champs bidimensionnelles invariantes sous les transformations conformes. L'algebre des transformations conformes de l'espace-temps presente une caracteristique remarquable: en deux dimensions elle possede un nombre infini de generateurs. Cette propriete impose de telles conditions aux fonctions de correlations qu'il est possible de les evaluer sans aucune approximation. Les champs des theories conformes appartiennent a des representations de plus haut poids de l'algebre de Virasoro, une extension centrale de l'algebre conforme du plan. Ces representations sont etiquetees par h, le poids conforme de leur vecteur de plus haut poids, et par la charge centrale c, le facteur de l'extension centrale, commune a toutes les representations d'une meme theorie. Les theories conformes minimales sont constituees d'un nombre fini de representations. Parmi celles-ci se trouvent des theories unitaires dont les representation forment la serie discrete de l'algebre de Virasoro; leur poids h a la forme h_{p,q}(m)=[ (p(m+1) -qm)^2-1] (4m(m+1)), ou p,q et m sont des entiers positifs et p+q<= m+1. L'entier m parametrise la charge centrale: c(m)=1 -{6over m(m+1)} avec n>= 2. Ces representations possedent un sous-espace invariant engendre par deux sous-representations avec h_1=h_{p,q} + pq et h_2=h_{p,q} + (m-p)(m+1-q) dont chacun des vecteurs de plus haut poids portent le nom de vecteur singulier et sont notes respectivement |Psi _{p,q}> et |Psi_{m-p,m+1-q}>. . Les theories super-conformes sont une version super-symetrique des theories conformes. Leurs champs appartiennent a des representation de plus haut poids de l'algebre de Neveu-Schwarz, une des deux extensions super -symetriques de l'algebre de Virasoro. Les theories super -conformes minimales possedent la meme structure que les theories conformes minimales. Les representations sont elements de la serie h_{p,q}= [ (p(m+2)-qm)^2-4] /(8m(m+2)) ou p,q et m sont des entiers positifs, p et q etant de meme parite, et p+q<= m+2. La charge centrale est donnee par c(m)={3over 2}-{12over m(m+2)} avec m >= 2. Les vecteurs singuliers | Psi_{p,q}> et |Psi_{m-p,m+2-q} > sont respectivement de poids h _{p,q}+pq/2 et h_ {p,q}+(m-p)(m+2-q)/2.. Les vecteurs singuliers ont une norme nulle et on doit les eliminer des representations pour que celles -ci soient unitaires. Cette elimination engendrent des equations (super-)differentielles qui dependent directement de la forme explicite des vecteurs singuliers et auxquelles doivent obeir les fonctions de correlations de la theorie. Ainsi la connaissance de ces vecteurs singuliers est intimement reliee au calcul des fonctions de correlation. Les equations definissant les vecteurs singuliers forment un systeme lineaire surdetermine dont le nombre d'equations est de l'ordre de N(pq), le nombre de partitions de l'entier pq. Puisque les vecteurs singuliers jouent un role capital en theorie conforme, il est naturel de chercher des formes explicites pour les vecteurs (ou pour des familles infinies de ceux -ci). Nous donnons ici la forme explicite pour la famille infinie de vecteurs singuliers ayant un de ses indices egal a 1, pour les algebres de Virasoro et de Neveu-Schwarz. Depuis ces decouvertes, d'autres techniques de construction des vecteurs singuliers ont ete developpees, dont celle de Bauer, Di Francesco, Itzykson et Zuber pour l'algebre de Virasoro qui reproduit directement l'expression explicite des vecteurs singuliers |Psi _{1,q}> et |Psi_{p,1}>. Ils ont utilise l'algebre des produits d'operateurs et la fusion entre representations irreductibles pour engendrer des relations de recurence produisant les vecteurs singuliers. Dans le dernier chapitre de cette these nous adaptons cet algorithme a la construction des vecteurs singuliers de l'algebre de Neveu-Schwarz.

Skeletogenesis in sea urchin larvae under modified gravity conditions.

PubMed

Marthy, H J; Gasset, G; Tixador, R; Eche, B; Schatt, P; Dessommes, A; Marthy, U; Bacchieri, R

1998-01-01

From many points of view, skeletogenesis in sea urchins has been well described. Based on this scientific background and considering practical aspects of sea urchin development (i.e. availability of material, size of larvae, etc.), we wanted to know whether orderly skeletogenesis requires the presence of gravity. The objective has been approached by three experiments successfully performed under genuine microgravity conditions (in the STS-65 IML-2 mission of 1994; in the Photon-10 IBIS mission of 1995 and in the STS-76 S/MM-03 mission of 1996). Larvae of the sea urchin Sphaerechinus granularis were allowed to develop in microgravity conditions for several days from blastula stage onwards (onset of skeletogenesis). At the end of the missions, the recovered skeletal structures were studied with respect to their mineral composition, architecture and size. Live larvae were also recovered for post-flight culture. The results obtained clearly show that the process of mineralisation is independent of gravity: that is, the skeletogenic cells differentiate correctly in microgravity. However, abnormal skeleton architectures were encountered, particularly in the IML-2 mission, indicating that the process of positioning of the skeletogenic cells may be affected, directly or indirectly, by environmental factors, including gravity. Larvae exposed to microgravity from blastula to prism/early pluteus stage for about 2 weeks (IBIS mission), developed on the ground over the next 2 months into normal metamorphosing individuals.

New iGrav superconducting gravimeter: accuracy, drift and first results

NASA Astrophysics Data System (ADS)

Le Moigne, N.; Champollion, C.; Warburton, R. J.; Bayer, R.; Deville, S.; Doerflinger, E.; chery, J.; Vernant, P.; Boudin, F.; Collard, P.

2011-12-01

A GWR iGrav superconducting gravimeter has been installed in the Larzac karstic area (Southern France near the Mediterranean Sea, elevation 800m, karst thickness 200m). Continuous sub-μGal gravity measurements are needed to study water storage and transfer in the non-saturated zone of the karstic area. The GWR iGrav is a new generation of superconducting gravimeter of reduced size (Dewar 15L) with simplified installation. At first, the specifications of the iGrav site will be presented, then the drift behaviour and the data processing. The drift quickly decreases to less than 0.1 μGal per day and only a few offsets are observed in the data. In order to look at the stability of the iGrav over a wide time period, a FG5 gravimeter is used for bi-monthly absolute gravity measurements and for frequent calibrations. As a result of the installation, the iGrav allows sub-μGal gravity monitoring only a few weeks after the beginning of the installation. After having discussed the instrumental and data processing points of view, preliminary results on the local karstic water storage will be presented and interpreted by combining different geophysical data. Continuous gravity data allow to study processes at different timescale such as summer evapotranspiration or high precipitating event characteristic of the Mediterranean autumn.

Effect of IOP based infusion system with and without balanced phaco tip on cumulative dissipated energy and estimated fluid usage in comparison to gravity fed infusion in torsional phacoemulsification.

PubMed

Malik, Praveen K; Dewan, Taru; Patidar, Arun Kr; Sain, Ekta

2017-01-01

To evaluate the effect of three different combinations of tip designs and infusion systems in torsional phacoemulsification (INFINITI and CENTURION) in patients with cataract. According to the manufacturer, two unique improvements in the Centurion are: active fluid dynamic management system and use of an intrepid balanced tip. The study specifically aimed to evaluate the beneficial effects, if any, of change in tip design and infusion system individually and in combination on both per-operative parameters as well as endothelial health over 6 months. One hundred and twenty six consenting patients of grade 4.0-6.9 senile cataract were randomized into three groups for phacoemulsification: Group A ( n  = 42): Gravity fed infusion system and 45 0 Kelman miniflared ABS phaco tip; Group B ( n  = 42): intraocular pressure (IOP) based infusion system and 45 0 Kelman miniflared ABS phaco tip; Group C ( n  = 42): IOP based infusion system and 45 0 Intrepid balanced phaco tip. The cumulative dissipated energy (CDE), estimated fluid usage (EFU) and total aspiration time (TAT) were compared peroperatively. The endothelial parameters were followed up postoperatively for six months. The three arms were matched for age ( p  = 0.525), gender ( p  = 0.96) and grade of cataract ( p  = 0.177). Group C was associated with significant reductions in CDE ( p  = 0.001), EFU ( p  < 0.0005) as well as TAT ( p  = 0.001) in comparison to the other groups. All three groups had comparable baseline endothelial cell density ( p  = 0.876) and central corneal thickness ( p  = 0.561). On post-operative evaluation, although all groups were comparable till 3 months, by 6 months, the percentage losses in endothelial cell density were significantly lower in group C as compared to the other groups. Use of an IOP based phacoemulsification system in association with use of the Intrepid balanced tip reduces the CDE, EFU and TAT in comparison to a gravity fed system with a mini flared tip or IOP based system with a mini flared tip while also providing better endothelial preservation thus favouring the use of an IOP fed system with a balanced tip. Trial registration No.: CTRI/2016/06/007022.

New advanced tools for combined ULF wave analysis of multipoint space-borne and ground observations: application to single event and statistical studies

NASA Astrophysics Data System (ADS)

Balasis, G.; Papadimitriou, C.; Daglis, I. A.; Georgiou, M.; Giamini, S. A.

2013-12-01

In the past decade, a critical mass of high-quality scientific data on the electric and magnetic fields in the Earth's magnetosphere and topside ionosphere has been progressively collected. This data pool will be further enriched by the measurements of the upcoming ESA/Swarm mission, a constellation of three satellites in three different polar orbits between 400 and 550 km altitude, which is expected to be launched in November 2013. New analysis tools that can cope with measurements of various spacecraft at various regions of the magnetosphere and in the topside ionosphere as well as ground stations will effectively enhance the scientific exploitation of the accumulated data. Here, we report on a new suite of algorithms based on a combination of wavelet spectral methods and artificial neural network techniques and demonstrate the applicability of our recently developed analysis tools both for individual case studies and statistical studies of ultra-low frequency (ULF) waves. First, we provide evidence for a rare simultaneous observation of a ULF wave event in the Earth's magnetosphere, topside ionosphere and surface: we have found a specific time interval during the Halloween 2003 magnetic storm, when the Cluster and CHAMP spacecraft were in good local time (LT) conjunction, and have examined the ULF wave activity in the Pc3 (22-100 mHz) and Pc4-5 (1-22 mHz) bands using data from the Geotail, Cluster and CHAMP missions, as well as the CARISMA and GIMA magnetometer networks. Then, we perform a statistical study of Pc3 wave events observed by CHAMP for the full decade (2001-2010) of the satellite vector magnetic data: the creation of a database of such events enabled us to derive valuable statistics for many important physical properties relating to the spatio-temporal location of these waves, the wave power and frequency, as well as other parameters and their correlation with solar wind conditions, magnetospheric indices, electron density data, ring current decay and radiation belt enhancements. The work leading to this paper has received funding from the European Union's Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520 for the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project.

Retrieval of temperature profiles from CHAMP for climate monitoring: intercomparison with Envisat MIPAS and GOMOS and different atmospheric analyses

NASA Astrophysics Data System (ADS)

Gobiet, A.; Kirchengast, G.; Manney, G. L.; Borsche, M.; Retscher, C.; Stiller, G.

2007-02-01

This study describes and evaluates a Global Navigation Satellite System (GNSS) radio occultation (RO) retrieval scheme particularly aimed at delivering bias-free atmospheric parameters for climate monitoring and research. The focus of the retrieval is on the sensible use of a priori information for careful high-altitude initialisation in order to maximise the usable altitude range. The RO retrieval scheme has been meanwhile applied to more than five years of data (September 2001 to November 2006) from the German CHAllenging Minisatellite Payload for geoscientific research (CHAMP) satellite. In this study it was validated against various correlative datasets including the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the Global Ozone Monitoring for Occultation of Stars (GOMOS) sensors on Envisat, five different atmospheric analyses, and the operational CHAMP retrieval product from GeoForschungsZentrum (GFZ) Potsdam. In the global mean within 10 to 30 km altitude we find that the present validation observationally constrains the potential RO temperature bias to be <0.2 K. Latitudinally resolved analyses show biases to be observationally constrained to <0.2-0.5 K up to 35 km in most cases, and up to 30 km in any case, even if severely biased (about 10 K or more) a priori information is used in the high altitude initialisation of the retrieval. No evidence is found for the 10-35 km altitude range of RO bias sources other than those potentially propagated downward from initialisation, indicating that the widely quoted RO promise of "unbiasedness and long-term stability due to intrinsic self-calibration" can indeed be realized given care in the data processing to strictly limit structural uncertainty. The results demonstrate that an adequate high-altitude initialisation technique is crucial for accurate stratospheric RO retrievals and that still common methods of initialising the involved hydrostatic integral with an upper boundary temperature or pressure value derived from meteorological analyses is prone to introduce biases from the initialisation data to the retrieved temperatures down to below 25 km. Above 30 to 35 km, GNSS RO delivers a considerable amount of observed information up to around 40 km, which is particularly interesting for numerical weather prediction (NWP) systems, where direct assimilation of non-initialized (a priori-free) observed RO bending angles is thus the method of choice. The results underline the value of RO for climate applications.

Retrieval of temperature profiles from CHAMP for climate monitoring: intercomparison with Envisat MIPAS and GOMOS and different atmospheric analyses

NASA Astrophysics Data System (ADS)

Gobiet, A.; Kirchengast, G.; Manney, G. L.; Borsche, M.; Retscher, C.; Stiller, G.

2007-07-01

This study describes and evaluates a Global Navigation Satellite System (GNSS) radio occultation (RO) retrieval scheme particularly aimed at delivering bias-free atmospheric parameters for climate monitoring and research. The focus of the retrieval is on the sensible use of a priori information for careful high-altitude initialisation in order to maximise the usable altitude range. The RO retrieval scheme has been meanwhile applied to more than five years of data (September 2001 to present) from the German CHAllenging Minisatellite Payload for geoscientific research (CHAMP) satellite. In this study it was validated against various correlative datasets including the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the Global Ozone Monitoring for Occultation of Stars (GOMOS) sensors on Envisat, five different atmospheric analyses, and the operational CHAMP retrieval product from GeoForschungsZentrum (GFZ) Potsdam. In the global mean within 10 to 30 km altitude we find that the present validation observationally constrains the potential RO temperature bias to be <0.2 K. Latitudinally resolved analyses show biases to be observationally constrained to <0.2-0.5 K up to 35 km in most cases, and up to 30 km in any case, even if severely biased (about 10 K or more) a priori information is used in the high altitude initialisation of the retrieval. No evidence is found for the 10-35 km altitude range of residual RO bias sources other than those potentially propagated downward from initialisation, indicating that the widely quoted RO promise of "unbiasedness and long-term stability due to intrinsic self-calibration" can indeed be realised given care in the data processing to strictly limit structural uncertainty. The results thus reinforce that adequate high-altitude initialisation is crucial for accurate stratospheric RO retrievals. The common method of initialising, at some altitude in the upper stratosphere, the hydrostatic integral with an upper boundary temperature or pressure value derived from meteorological analyses is prone to introduce biases from the upper boundary down to below 25 km. Also above 30 to 35 km, GNSS RO delivers a considerable amount of observed information up to around 40 km, which is particularly interesting for numerical weather prediction (NWP) systems, where direct assimilation of non-initialised observed RO bending angles (free of a priori) is thus the method of choice. The results underline the value of RO for climate applications.

LCS-1: a high-resolution global model of the lithospheric magnetic field derived from CHAMP and Swarm satellite observations

NASA Astrophysics Data System (ADS)

Olsen, Nils; Ravat, Dhananjay; Finlay, Christopher C.; Kother, Livia K.

2017-12-01

We derive a new model, named LCS-1, of Earth's lithospheric field based on four years (2006 September-2010 September) of magnetic observations taken by the CHAMP satellite at altitudes lower than 350 km, as well as almost three years (2014 April-2016 December) of measurements taken by the two lower Swarm satellites Alpha and Charlie. The model is determined entirely from magnetic 'gradient' data (approximated by finite differences): the north-south gradient is approximated by first differences of 15 s along-track data (for CHAMP and each of the two Swarm satellites), while the east-west gradient is approximated by the difference between observations taken by Swarm Alpha and Charlie. In total, we used 6.2 mio data points. The model is parametrized by 35 000 equivalent point sources located on an almost equal-area grid at a depth of 100 km below the surface (WGS84 ellipsoid). The amplitudes of these point sources are determined by minimizing the misfit to the magnetic satellite 'gradient' data together with the global average of |Br| at the ellipsoid surface (i.e. applying an L1 model regularization of Br). In a final step, we transform the point-source representation to a spherical harmonic expansion. The model shows very good agreement with previous satellite-derived lithospheric field models at low degree (degree correlation above 0.8 for degrees n ≤ 133). Comparison with independent near-surface aeromagnetic data from Australia yields good agreement (coherence >0.55) at horizontal wavelengths down to at least 250 km, corresponding to spherical harmonic degree n ≈ 160. The LCS-1 vertical component and field intensity anomaly maps at Earth's surface show similar features to those exhibited by the WDMAM2 and EMM2015 lithospheric field models truncated at degree 185 in regions where they include near-surface data and provide unprecedented detail where they do not. Example regions of improvement include the Bangui anomaly region in central Africa, the west African cratons, the East African Rift region, the Bay of Bengal, the southern 90°E ridge, the Cretaceous quiet zone south of the Walvis Ridge and the younger parts of the South Atlantic.

KSC-03PD-2741

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. Workers in the spacecraft processing facility on North Vandenberg Air Force Base get ready to begin processing the Gravity Probe B experiment, including setting up mechanical and electrical ground support equipment, making necessary connections and conditioning the spacecraft battery. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2740

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. Workers in the spacecraft processing facility on North Vandenberg Air Force Base get ready to begin processing the Gravity Probe B experiment, including setting up mechanical and electrical ground support equipment, making necessary connections and conditioning the spacecraft battery. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-03PD-2867

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. In the spacecraft processing facility on North Vandenberg Air Force Base, the Gravity Probe B experiment sits on an assembly and test stand where it has been subject to various prelaunch testing. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center. The targeted launch date is Dec. 6, 2003.

KSC-03PD-2739

NASA Technical Reports Server (NTRS)

2003-01-01

VANDENBERG AFB, CALIF. Workers in the spacecraft processing facility on North Vandenberg Air Force Base get ready to begin processing the Gravity Probe B experiment, including setting up mechanical and electrical ground support equipment, making necessary connections and conditioning the spacecraft battery. The Gravity Probe B will launch a payload of four gyroscopes into low-Earth polar orbit to test two extraordinary predictions of Albert Einsteins general theory of relativity: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earths rotation drags space and time around with it). Once in orbit, for 18 months each gyroscopes spin axis will be monitored as it travels through local spacetime, observing and measuring these effects. The experiment was developed by Stanford University, Lockheed Martin and NASAs Marshall Space Flight Center.

KSC-2011-4450

NASA Image and Video Library

2011-06-15

CAPE CANAVERAL, Fla. -- In the Astrotech payload processing facility in Titusville, Fla., technicians prepare a solar panel for attachment to NASA's Gravity Recovery and Interior Laboratory, or GRAIL. The United Launch Alliance Delta II rocket that will carry the twin GRAIL spacecraft into lunar orbit is fully stacked at NASA's Space Launch Complex 17B and launch is scheduled for Sept. 8. The GRAIL mission is a part of NASA's Discovery Program. GRAIL will fly twin spacecraft in tandem orbits around the moon for several months to measure its gravity field. The mission also will answer longstanding questions about Earth's moon and provide scientists a better understanding of how Earth and other rocky planets in the solar system formed. For more information, visit http://solarsystem.nasa.gov/grail. Photo credit: NASA/Frank Michaux

KSC-2011-6092

NASA Image and Video Library

2011-07-30

CAPE CANAVERAL, Fla. -- Preparations are under way to transport the protective canister housing NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft to the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. In the HPF, the spacecraft will undergo two days of fueling activities. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Charisse Nahser

KSC-2011-6465

NASA Image and Video Library

2011-08-12

CAPE CANAVERAL, Fla. -- At Astrotech Space Operation's payload processing facility in Titusville, Fla., a protective canister encases NASA's twin Gravity Recovery and Interior Laboratory spacecraft. Preparations are under way to transport the lunar probes, attached to a spacecraft adapter ring in their side-by-side launch configuration, to the launch pad. The spacecraft will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Jim Grossmann

KSC-2011-6097

NASA Image and Video Library

2011-07-30

CAPE CANAVERAL, Fla. -- The protective canister housing NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft is lifted from around the mylar-covered spacecraft in the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. In the HPF, the spacecraft will undergo two days of fueling activities. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Charisse Nahser

KSC-2011-6104

NASA Image and Video Library

2011-07-30

CAPE CANAVERAL, Fla. -- Lockheed Martin technicians examine NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft before they are moved onto workstands in the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. In the HPF, the spacecraft will undergo two days of fueling activities. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Charisse Nahser

KSC-2011-6320

NASA Image and Video Library

2011-08-09

CAPE CANAVERAL, Fla. -- At Astrotech Space Operation's payload processing facility in Titusville, Fla., preparations are under way to determine the weight of one of NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft before the spacecraft are stacked in their launch configuration in readiness for transport to the launch pad. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Jim Grossmann

KSC-2011-6110

NASA Image and Video Library

2011-07-30

CAPE CANAVERAL, Fla. -- Preparations are under way to lift the second of NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft to a workstand in the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. In the HPF, the spacecraft will undergo two days of fueling activities. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Charisse Nahser

KSC-2011-6095

NASA Image and Video Library

2011-07-30

CAPE CANAVERAL, Fla. -- Lockheed Martin technicians oversee the lift of the protective canister housing NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft from the transporter in the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. In the HPF, the spacecraft will undergo two days of fueling activities. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Charisse Nahser

KSC-2011-6099

NASA Image and Video Library

2011-07-30

CAPE CANAVERAL, Fla. -- Lockheed Martin technicians push NASA's mylar-covered twin Gravity Recovery and Interior Laboratory lunar spacecraft toward the work area of the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. In the HPF, the spacecraft will undergo two days of fueling activities. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Charisse Nahser

KSC-2011-6105

NASA Image and Video Library

2011-07-30

CAPE CANAVERAL, Fla. -- Preparations are under way to lift one of NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft onto a workstand in the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. In the HPF, the spacecraft will undergo two days of fueling activities. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Charisse Nahser

KSC-2011-6321

NASA Image and Video Library

2011-08-09

CAPE CANAVERAL, Fla. -- At Astrotech Space Operation's payload processing facility in Titusville, Fla., Lockheed Martin technicians determine the readiness of one of NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft before the spacecraft are stacked in their launch configuration in preparation for transport to the launch pad. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Jim Grossmann