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Sample records for agulhas return current

  1. Understanding Thermohaline Mixing in the Agulhas Return Current from Seismic and Finestructure Observations

    DTIC Science & Technology

    2014-07-01

    interleaving thermohaline intrusions at submesoscales . Indian Ocean; Agulhas Current System; seismic observations Unclassified Unclassified...zone that is characterized by the presence of a strong temperature front and is manifested by interleaving thermohaline intrusions at submesoscales ...to elucidate submesoscale and fine scale frontal zone mixing processes by assessing how mesoscale and fine-scale features influence thermohaline

  2. New Thought on the Agulhas Current

    NASA Astrophysics Data System (ADS)

    Meyer, A. A.; Lutjeharms, J. R.; Whittle, C.; Weeks, S.; Roy, C.

    2002-12-01

    A more complete understanding of the fundamental dynamics of the Agulhas Current Proper is evolving rapidly because of new discoveries. The discovery of the Agulhas Undercurrent (Beal and Bryden, 1997) had a profound effect on the overall estimate of the Agulhas Current transport. Also, the discovery of Schouten et al. (2002) that Mozambique Channel Eddies are responsible for the formation of Natal Pulses, which in turn is significantly related to the Indian-Atlantic Interocean leakage of water masses, had a profound effect on how the Agulhas Current System is now perceived. These new insights, historical hydrographic data, and satellite remote sensed data contributed to the formulation of 3 hypotheses on the fundamental dynamics of the Agulhas Current Proper. Hypothesis one: Directly north of the Delagoa Bight the Mozambique Channel Eddies encounter the most northern extend of the shallow Agulhas Current and interact with the seaward side of this Western Boundary Current to form the Delagoa Pulse, obtaining its required cyclonicity from the Delagoa Bight Lee Eddy. Hypothesis two: Water masses of the Agulhas Undercurrent and Red Sea Water are upwelled within the Delagoa Bight Lee eddy which forms the southward propagating Delagoa Pulse. Hence, parts of the Agulhas Undercurrent are transported back into the Atlantic Ocean via a fast-track (10 to 20 km/day) mechanism, the Delagoa Pulse. Hypothesis three: Delagoa Pulses act as mechanisms for the injection of upwelled Agulhas Undercurrent water masses and Red Sea Water onto the eastern Agulhas Bank, supplying a semi-continuous density flow along the 100 m isobath. This density current originates from the Indian Ocean sector of the Agulhas Bank at the Port Alfred Upwelling Cell, feeds the cold bottom ridge, rounds the Alphard Banks, and enters the Atlantic Ocean sector of the Agulhas Bank. The physical and chemical properties of the density flow coined the Lutjeharms (Indian-Atlantic Interocean secondary leakage) Return

  3. Assessment of Hybrid Coordinate Model Velocity Fields During Agulhas Return Current 2012 Cruise

    DTIC Science & Technology

    2013-06-01

    104, 5151–5176. Bleck, R., C. Rooth, D. Hu, and L. Smith, 1992: Salinity- driven thermocline transients in a wind- and thermohaline -forced...isopycnic coordinate model of the North Atlantic. J. Phys. Oceanogr., 22, 1486-1505. Bleck, R., 2002: An oceanic general circulation model framed in...core Agulhas Plateau Eddies. AGU Chapman Conference, The Agulhas System and its Role in Changing Ocean Circulation , Climate, and Marine Ecosystems

  4. Submesoscale cyclones in the Agulhas current

    NASA Astrophysics Data System (ADS)

    Krug, M.; Swart, S.; Gula, J.

    2017-01-01

    Gliders were deployed for the first time in the Agulhas Current region to investigate processes of interactions between western boundary currents and shelf waters. Continuous observations from the gliders in water depths of 100-1000 m and over a period of 1 month provide the first high-resolution observations of the Agulhas Current's inshore front. The observations collected in a nonmeandering Agulhas Current show the presence of submesoscale cyclonic eddies, generated at the inshore boundary of the Agulhas Current. The submesoscale cyclones are often associated with warm water plumes, which extend from their western edge and exhibit strong northeastward currents. These features are a result of shear instabilities and extract their energy from the mean Agulhas Current jet.

  5. Observed eddy dissipation in the Agulhas Current

    NASA Astrophysics Data System (ADS)

    Braby, Laura; Backeberg, Björn C.; Ansorge, Isabelle; Roberts, Michael J.; Krug, Marjolaine; Reason, Chris J. C.

    2016-08-01

    Analyzing eddy characteristics from a global data set of automatically tracked eddies for the Agulhas Current in combination with surface drifters as well as geostrophic currents from satellite altimeters, it is shown that eddies from the Mozambique Channel and south of Madagascar dissipate as they approach the Agulhas Current. By tracking the offshore position of the current core and its velocity at 30°S in relation to eddies, it is demonstrated that eddy dissipation occurs through a transfer of momentum, where anticyclones consistently induce positive velocity anomalies, and cyclones reduce the velocities and cause offshore meanders. Composite analyses of the anticyclonic (cyclonic) eddy-current interaction events demonstrate that the positive (negative) velocity anomalies propagate downstream in the Agulhas Current at 44 km/d (23 km/d). Many models are unable to represent these eddy dissipation processes, affecting our understanding of the Agulhas Current.

  6. Frontolysis by surface heat flux in the Agulhas Return Current region with a focus on mixed layer processes: observation and a high-resolution CGCM

    NASA Astrophysics Data System (ADS)

    Ohishi, Shun; Tozuka, Tomoki; Komori, Nobumasa

    2016-12-01

    Detailed mechanisms for frontogenesis/frontolysis of the Agulhas Return Current (ARC) Front, defined as the maximum of the meridional sea surface temperature (SST) gradient at each longitude within the ARC region (40°-50°E, 55°-35°S), are investigated using observational datasets. Due to larger (smaller) latent heat release to the atmosphere on the northern (southern) side of the front, the meridional gradient of surface net heat flux (NHF) is found throughout the year. In austral summer, surface warming is weaker (stronger) on the northern (southern) side, and thus the NHF tends to relax the SST front. The weaker (stronger) surface warming, at the same time, leads to the deeper (shallower) mixed layer on the northern (southern) side. This enhances the frontolysis, because deeper (shallower) mixed layer is less (more) sensitive to surface warming. In austral winter, stronger (weaker) surface cooling on the northern (southern) side contributes to the frontolysis. However, deeper (shallower) mixed layer is induced by stronger (weaker) surface cooling on the northern (southern) side and suppresses the frontolysis, because the deeper (shallower) mixed layer is less (more) sensitive to surface cooling. Therefore, the frontolysis by the NHF becomes stronger (weaker) through the mixed layer processes in austral summer (winter). The cause of the meridional gradient of mixed layer depth is estimated using diagnostic entrainment velocity and the Monin-Obukhov depth. Furthermore, the above mechanisms obtained from the observation are confirmed using outputs from a high-resolution coupled general circulation model. Causes of model biases are also discussed.

  7. Relating Agulhas Leakage to the Agulhas Current Retroflection Location

    DTIC Science & Technology

    2009-11-03

    observations and oceanographic data for ocean circulations and climate stud- ies, chap. 5, Elsevier Oceanographic Series, 79–97, 2000. Garzoli, S. L. and...branch return flow of the Atlantic meridional overturning circulation (Gordon, 1986; Weijer et al., 1999; Peeters et al., 2004; Biastoch et al., 2008a...into the large-scale circulation . Both models have 46 vertical lay- ers, with layer thicknesses ranging from 6 m at the surface to 250 m at depth, and

  8. Wind changes above warm Agulhas Current eddies

    NASA Astrophysics Data System (ADS)

    Rouault, M.; Verley, P.; Backeberg, B.

    2016-04-01

    Sea surface temperature (SST) estimated from the Advanced Microwave Scanning Radiometer E onboard the Aqua satellite and altimetry-derived sea level anomalies are used south of the Agulhas Current to identify warm-core mesoscale eddies presenting a distinct SST perturbation greater than to 1 °C to the surrounding ocean. The analysis of twice daily instantaneous charts of equivalent stability-neutral wind speed estimates from the SeaWinds scatterometer onboard the QuikScat satellite collocated with SST for six identified eddies shows stronger wind speed above the warm eddies than the surrounding water in all wind directions, if averaged over the lifespan of the eddies, as was found in previous studies. However, only half of the cases showed higher wind speeds above the eddies at the instantaneous scale; 20 % of cases had incomplete data due to partial global coverage by the scatterometer for one path. For cases where the wind is stronger above warm eddies, there is no relationship between the increase in surface wind speed and the SST perturbation, but we do find a linear relationship between the decrease in wind speed from the centre to the border of the eddy downstream and the SST perturbation. SST perturbations range from 1 to 6 °C for a mean eddy SST of 15.9 °C and mean SST perturbation of 2.65 °C. The diameter of the eddies range from 100 to 250 km. Mean background wind speed is about 12 m s-1 (mostly southwesterly to northwesterly) and ranging mainly from 4 to 16 m s-1. The mean wind increase is about 15 %, which corresponds to 1.8 m s-1. A wind speed increase of 4 to 7 m s-1 above warm eddies is not uncommon. Cases where the wind did not increase above the eddies or did not decrease downstream had higher wind speeds and occurred during a cold front associated with intense cyclonic low-pressure systems, suggesting certain synoptic conditions need to be met to allow for the development of wind speed anomalies over warm-core ocean eddies. In many cases

  9. Coastal upwelling on the far eastern Agulhas Bank associated with large meanders in the Agulhas Current

    NASA Astrophysics Data System (ADS)

    Goschen, W. S.; Bornman, T. G.; Deyzel, S. H. P.; Schumann, E. H.

    2015-06-01

    Six large solitary meanders in the Agulhas Current, so-called Natal Pulses, propagated down the eastern coast of South Africa between 2009 and 2011. Their influence on the coastal waters between Port Alfred and Algoa Bay, on the far eastern Agulhas Bank, was measured by thermistor strings moored at 30-80 m bottom depths and two current metres (30 m bottom depth) located at both sides of Algoa Bay. During all events active upwelling lasting 1-3 weeks was observed over the inner shelf and in Algoa Bay. During upwelling the isotherms ascended at an average rate of 1.8 m day-1 as the cold bottom layer increased in thickness to 40-60 m, although upwelled water did not break the surface in all cases. Cold water remained in the area for a further 2-3 weeks. During three Natal Pulses the water temperatures at the outer moorings initially increased as the plume of the leading edge (crest) of the meander moved onshore. During one Natal Pulse upwelling was recorded before the warm water plume impacted the moorings. At the onset of upwelling currents switched to the southwest in the case of Bird Island and southward at the Cape Recife inner-bay site and reached a maximum speed of 80 cm s-1. During all Natal Pulses cold bottom water (10-12 °C) flooded over the 80 m bottom depth moorings as the crest of the meander moved onshore, but also around the same time the core of the Agulhas Current began to move offshore. In all cases upwelling was wide-spread.

  10. Atmospheric driving forces for the Agulhas Current in the subtropics

    NASA Astrophysics Data System (ADS)

    Fetter, A.; Lutjeharms, J. R. E.; Matano, R. P.

    2007-08-01

    The Agulhas Current is the western boundary current of the South Indian Ocean and is thought to play an important role in the global overturning circulation. In this study, we investigate the contribution from the wind stress field over each ocean basin of the southern hemisphere to the variability of Agulhas Current transport. We ran a series of experiments using the Modular Ocean Model 2. The model grid extends from 20°S to 70°S and has a horizontal resolution of $1\\!/\\!_{2° with 25 levels in the vertical. The first experiment was forced with monthly means of the wind stress field from the project ERA 40 from ECMWF. In three other sensitivity experiments, the model was forced with the climatological mean over the whole domain plus the monthly wind stress anomalies (Jan/1979-Dec/2001) over one of the three ocean basins to whit: the South Atlantic, the South Indian and the South Pacific. The results show that inter-annual variations in the Agulhas Current transport are due largely to the wind field over the South Indian Ocean, whereas annual variations are driven by the wind field over both the South Atlantic and South Indian oceans. The annual signal from the South Atlantic is shown to move equatorward along the southeastern coast of Africa through coastally trapped waves.

  11. Origins and impacts of mesoscale meanders in the Agulhas Current

    NASA Astrophysics Data System (ADS)

    Elipot, S.; Beal, L. M.

    2014-12-01

    The Agulhas Current (AC) is the western boundary current of the South Indian subtropical gyre and is also the pathway for the inter-basin exchange of water, heat and salt between the Indian Ocean and the Atlantic Ocean, and thus a crucial part of the global overturning circulation of the world ocean. The AC, which otherwise flows stably along the coast of South Africa, undergoes dramatic offshore excursions from its mean path, forming large mesoscale solitary meanders propagating downstream and potentially linked to the leakage of Indian Ocean waters to the South Atlantic. These irregular meander events have been referred to as Natal Pulses.Here we present new observations and analyses of Agulhas meanders using full-depth velocity mooring observations from the Agulhas Current Time series experiment (ACT). Detailed analyses of the in-situ velocity reveal important differences between the behavior of the flow during solitary meander events and during meander events of smaller amplitude. During solitary meanders, an onshore cyclonic circulation and an offshore anticyclonic circulation act in concert to displace the jet offshore, leading to sudden and strong positive conversion of kinetic energy of the mean flow to the meander. In contrast, smaller amplitude meanderings are principally represented by a single cyclonic circulation spanning the entire jet that acts to displace the jet without significantly extracting kinetic energy from the mean flow. Solitary meander events can be traced upstream using satellite altimetry and linked to either Mozambique Channel eddies or Madagascar dipoles, the latter possibly part of a basin-wide pattern of propagating sea level anomalies consistent with Rossby wave dynamics. However, only a small number of these anomalies lead to solitary meanders. Altimetric observations suggest 1.5 meanders per year and show that the two-year period during ACT when no events were observed is unprecedented in the 20-year satellite record.

  12. Observations of an early Agulhas current retroflection event in 2001: A temporary cessation of inter-ocean exchange south of Africa?

    NASA Astrophysics Data System (ADS)

    van Aken, H. M.; Lutjeharms, J. R. E.; Rouault, M.; Whittle, C.; de Ruijter, W. P. M.

    2013-02-01

    The exchange of heat and salt between the South Indian Ocean and South Atlantic Ocean, at the southern terminus of the Agulhas current, forms a crucial link in the global ocean circulation. It has been surmised that upstream retroflections in this current could produce temporary interruptions to the exchange, but that their impact would depend on the vertical extent of such retroflections and on their duration. The fortuitous presence at sea of a research vessel has now enabled us to investigate such an episode at subsurface levels in combination with remote sensing of the sea surface. We present here the first in situ evidence that an upstream or early retroflection can extend to a depth of well over 750 m and last for 5 months. This event was likely triggered upstream by the happenstance of two Natal Pulses, large cyclonic eddies inshore of the Agulhas current. These eddies short-circuited the Agulhas with its Return current, leading to the shedding of three large Agulhas rings in quick succession. The arrival of a third cyclonic eddy when the Retroflection was still quite retracted did not lead to another ring shedding event. The resulting early retroflection may have had the effect of stalling the shedding of Agulhas rings and their motion towards the Cape Basin. However, these early retroflections are too scarce to allow generic statements on their generation or consequences, and the relation with large-scale environmental factors. It is likely that the observed withdrawal of the retroflection into the Transkei Basin is a fortuitous result of a series of contingent interactions.

  13. Broadening not strengthening of the Agulhas Current since the early 1990s

    NASA Astrophysics Data System (ADS)

    Beal, Lisa M.; Elipot, Shane

    2016-12-01

    Western boundary currents—such as the Agulhas Current in the Indian Ocean—carry heat poleward, moderating Earth’s climate and fuelling the mid-latitude storm tracks. They could exacerbate or mitigate warming and extreme weather events in the future, depending on their response to anthropogenic climate change. Climate models show an ongoing poleward expansion and intensification of the global wind systems, most robustly in the Southern Hemisphere, and linear dynamical theory suggests that western boundary currents will intensify and shift poleward as a result. Observational evidence of such changes comes from accelerated warming and air-sea heat flux rates within all western boundary currents, which are two or three times faster than global mean rates. Here we show that, despite these expectations, the Agulhas Current has not intensified since the early 1990s. Instead, we find that it has broadened as a result of more eddy activity. Recent analyses of other western boundary currents—the Kuroshio and East Australia currents—hint at similar trends. These results indicate that intensifying winds may be increasing the eddy kinetic energy of boundary currents, rather than their mean flow. This could act to decrease poleward heat transport and increase cross-frontal exchange of nutrients and pollutants between the coastal ocean and the deep ocean. Sustained in situ measurements are needed to properly understand the role of these current systems in a changing climate.

  14. Madagascar corals track sea surface temperature variability in the Agulhas Current core region over the past 334 years

    PubMed Central

    Zinke, J.; Loveday, B. R.; Reason, C. J. C.; Dullo, W.-C.; Kroon, D.

    2014-01-01

    The Agulhas Current (AC) is the strongest western boundary current in the Southern Hemisphere and is key for weather and climate patterns, both regionally and globally. Its heat transfer into both the midlatitude South Indian Ocean and South Atlantic is of global significance. A new composite coral record (Ifaty and Tulear massive Porites corals), is linked to historical AC sea surface temperature (SST) instrumental data, showing robust correlations. The composite coral SST data start in 1660 and comprise 200 years more than the AC instrumental record. Numerical modelling exhibits that this new coral derived SST record is representative for the wider core region of the AC. AC SSTs variabilities show distinct cooling through the Little Ice Age and warming during the late 18th, 19th and 20th century, with significant decadal variability superimposed. Furthermore, the AC SSTs are teleconnected with the broad southern Indian and Atlantic Oceans, showing that the AC system is pivotal for inter-ocean heat exchange south of Africa. PMID:24637665

  15. Sea surface temperatures from the southern Benguela region from the Pliocene and Pleistocene: tracking Agulhas Current input into the SE Atlantic

    NASA Astrophysics Data System (ADS)

    Petrick, B. F.; McClymont, E.; Felder, S.; Lloyd, J. M.; Leng, M. J.

    2011-12-01

    The Pliocene and-Pleistocene epochs provide a way to understand the effect of past climate changes on key ocean currents. Here, we show results from ODP Site1087 (31.28'S, 15.19'E, 1374m water depth) to investigate changes in ocean circulation over the period of the mid-Pliocene warm period 3.0-3.5 Ma and compare these to the time of the 100 kyr Pleistocene glacial cycles. ODP 1087 is located in the South-eastern Atlantic Ocean, outside of the Benguela upwelling region; reconstructing the temperature history of the site will therefore provide an important data set from a part of the ocean that has few orbital-scale and continuous Pliocene temperature reconstructions. ODP 1087 can be used to investigate the history of the heat and salt transfer to the Atlantic Ocean from the Indian Ocean via the Agulhas Retroflection, which plays an important part in the global thermohaline circulation (Lutjeharms, 2007). Climate models and reconstructions for the most recent glacial-interglacial cycles have shown that changes to the strength of the heat transfer may cause major climatic changes and may play a role in transitions from glacial to interglacial events (Knorr & Lohmann, 2003). It is unknown how this transfer reacted to generally warmer global temperatures during the mid-Pliocene. Because the mid-Pliocene is seen as a model for future climate change it might provide a model for ocean circulations in a warmer world. Our approach is to apply several organic geochemistry proxies and foraminiferal analyses to reconstruct the history of ODP 1087. The UK37' index records differences in the unsaturated bonds in the C37 alkenones to reconstruct sea surface temperatures (Brassell et al., 1986). We present SSTs generated for the mid-Pliocene Warm period with a resolution of 4000 years. We compare this data to the time of the 100 kyr glacial cycles during the late Pleistocene. Even though ODP 1087 is located outside the Benguela upwelling system, it has lower Pliocene temperatures

  16. Spatio-temporal characteristics of Agulhas leakage: a model inter-comparison study

    NASA Astrophysics Data System (ADS)

    Holton, L.; Deshayes, J.; Backeberg, B. C.; Loveday, B. R.; Hermes, J. C.; Reason, C. J. C.

    2016-05-01

    Investigating the variability of Agulhas leakage, the volume transport of water from the Indian Ocean to the South Atlantic Ocean, is highly relevant due to its potential contribution to the Atlantic Meridional Overturning Circulation as well as the global circulation of heat and salt and hence global climate. Quantifying Agulhas leakage is challenging due to the non-linear nature of this process; current observations are insufficient to estimate its variability and ocean models all have biases in this region, even at high resolution . An Eulerian threshold integration method is developed to examine the mechanisms of Agulhas leakage variability in six ocean model simulations of varying resolution. This intercomparison, based on the circulation and thermohaline structure at the Good Hope line, a transect to the south west of the southern tip of Africa , is used to identify features that are robust regardless of the model used and takes into account the thermohaline biases of each model. When determined by a passive tracer method, 60 % of the magnitude of Agulhas leakage is captured and more than 80 % of its temporal fluctuations, suggesting that the method is appropriate for investigating the variability of Agulhas leakage. In all simulations but one, the major driver of variability is associated with mesoscale features passing through the section. High resolution ({<} 1/10°) hindcast models agree on the temporal (2-4 cycles per year) and spatial (300-500 km) scales of these features corresponding to observed Agulhas Rings. Coarser resolution models ({<} 1/4°) reproduce similar time scale of variability of Agulhas leakage in spite of their difficulties in representing the Agulhas rings properties. A coarser resolution climate model (2°) does not resolve the spatio-temporal mechanism of variability of Agulhas leakage. Hence it is expected to underestimate the contribution of Agulhas Current System to climate variability.

  17. The arrest of Agulhas retroflection during glaciations

    NASA Astrophysics Data System (ADS)

    Zharkov, V.; Nof, D.; Ortiz, J. D.; Paldor, N.; Chassignet, E.

    2011-12-01

    Paleoceanographic proxy data indicate that the Agulhas leakage into the South Atlantic was dramatically reduced during glacial times, thus probably resulting in the collapse of the Atlantic Meridional Overturning Circulation. In our former papers, we hypothesized that this was due to a northward shift of the zero wind stress curl that, in turn, forced the retroflection to occur farther north, where the slant of the coastline relative to the north is steep. Here we propose that strong westerlies (0.4 Pa implying a wind speed of ~ 12 m/s at zero degrees centigrade), which were supposedly common during glaciations, also could have arrested the leakage. This arrest occurs because the wind stress opposes the momentum flux associated with the retroflection and, therefore, the retroflection does not shift in latitude. We use a simple, nonlinear, "reduced gravity" model to show analytically and numerically that, under the above conditions, the eastward wind stress compensates for the zonal westward flow-force associated with the retroflection, thus avoiding the development and shedding of rings. For a nearly zonal wall, westerly winds, and small upper layer thickness along the wall, the arresting wind stress is found, theoretically, to be, τx~0.042α3/2ρf[(2fQ)3/g']1/4 where α is twice the retroflection eddy vorticity, ρ the water density, and Q the Agulhas Current volume flux; the remaining notation is conventional. According to this formula, wind typical for the Agulhas region during glacial times (0.4Pa) significantly affects the moderately strong Agulhas rings of large PV (α=0.1) but, with increasing α, the influence of wind quickly decreases, and becomes negligible for α>0.2. This theoretical result is in agreement with the results of the numerical simulations that we conducted. The numerics show that the wind tends to destroy the detached rings by squeezing them onto the wall, a result that is valid in both the straight and the kinked coast cases. In the

  18. On the return current of the equatorial electrojet

    NASA Astrophysics Data System (ADS)

    Onwumechili, C. A.

    In practically all cases, investigators have found it compelling to include westward currents on the flanks of the dip equator in order to fit well the observed dip equatorial magnetic variation profiles. There are three sources of the return currents: the geometry of field lines in the dynamo region, the polarization at the boundaries of enhanced conductivity at the dip equator, and the local neutral winds varying with height. These combine constructively, taking advantage of the peaks of conductivities around 5-deg-dip latitude, to provide for the return currents of practically all the eastward electrojet current. The return currents flow on the flanks of the dip equator for about 3.5 deg to about 20-deg-dip latitude, in any case not extending beyond the Sq focus. The negative correlation between the width and the intensity of the equatorial electrojet has been confirmed with data derived from physical model, indicating its origin in the return currents. The ionospheric current system so far detected by rockets is essentially in two layers. The intense lower layer including the return currents peaking around 5-deg-dip latitude may be associated with the equatorial electrojet; and the weak upper layer that maintains fairly steady altitude characteristics everywhere may be associated with the worldwide part of the Sq currents.

  19. Routes of Agulhas rings in the southeastern Cape Basin

    NASA Astrophysics Data System (ADS)

    Dencausse, Guillaume; Arhan, Michel; Speich, Sabrina

    2010-11-01

    Using weekly sea surface height data, Agulhas rings from the period October 1992 to December 2006 are detected and tracked, from their formation dates and throughout the Cape Basin. While 102 of them formed at the Agulhas Current retroflection, their subsequent subdivisions and junctions led to 199 trajectories. The rings geographical probability of presence shows two maxima. One, related to numerous ring passages, lies in the submarine bight formed by the Erica seamount, the Schmitt-Ott seamount, and the northeastern tip of the Agulhas Ridge. The other one, to be ascribed to topographic blocking of the eddies, is southeast of the latter obstacle. On the basis of topographic effects three routes for Agulhas rings are distinguished, a Northern route for rings that enter the south-Atlantic northeast of the Erica seamount, a Central one for those passing westward between this seamount and the tip of the Agulhas Ridge, and a Southern one farther south. Despite its bathymetric obstacles, the central route is the dominant one, both in terms of percentage of eddy crossings at its definition segment, and in terms of conveyed volume transport. Specific behaviours of rings along each route are described, referring to observations in previous studies. Some rings from the Northern route interact with the flow regime of the South African continental slope. The southernmost trajectories of the Central route are thought to settle the location of the climatological Subtropical Front in that region. The rings of the Southern route experience important core property alteration as they transit through the subantarctic domain.

  20. Long impulse currents associated with positive return strokes

    NASA Astrophysics Data System (ADS)

    Gomes, C.; Cooray, V.

    1998-05-01

    Long distant electric fields (400-500 km), generated by 26 positive cloud-to-ground flashes, were analysed. These flashes consist of well detectable long impulse fields subsequent to the initial peak. These hook-shaped slow fields are of considerable amplitude and have a mean duration of 1.24 ms. The amplitude of the long impulse field and the initial peak of the field show an approximately linear relationship. The long impulse current pertinent to positive return strokes which give rise to the measured long impulse fields were estimated. Flashes with these slow fields lower a mean charge of 50 C within the first 3 ms (excluding the first 100 μs which contains the initial peak), whereas the maximum charge lowered is 124 C. The mean of the ratio between the peak of the long impulse field and the initial peak is 41%. We also estimated the fields that will be generated by the long impulse currents at distances of 1000 km, 3000 km and 5000 km from the strike. The estimated peak magnetic fields at 5000 km have a mean of 52 pT. The peak magnetic fields observed at distances of about 5000 km from positive lightning flashes, which were associated with red sprites, are in the same range as the peak magnetic fields that we have calculated for the above 26 flashes. Hence we conclude that the observed Q-bursts which coincide with the occurrence of red sprites are due to the long impulse currents of positive return strokes. This slow field variation is rarely observed in connection with negative return strokes. Even when it is present, in the event of a negative return stroke, the amplitude and the duration of the tail are much less than those of its counterpart in positive return strokes. This explains why ionospheric lightning is predominantly associated with positive return strokes but not with negative return strokes.

  1. Agulhas Leakage changes in the Pliocene as a modulator of AMOC strength

    NASA Astrophysics Data System (ADS)

    Patel, N. P.; Deconto, R. M.; Condron, A.

    2015-12-01

    The leakage of Agulhas Current water into the South Atlantic is now thought to be a major player in global climate change. Its volume is linked to the strength and position of southern westerlies. Past changes in the westerly winds over the southern ocean have been noted on glacial-interglacial timescales, in response to both Northern Hemispheric conditions and changes in Antarctic ice volume. The Pliocene to Pleistocene transition, associated cooling and Northern Hemisphere glaciation may have related to changes in Antarctica and the Southern Ocean, affecting both the position and strength of southern westerly winds. A northward shift in the westerlies, observed in past records of glaciation events, is thought to restrict the flow of warm, salty water from the Indian Ocean into the Atlantic, potentially impacting the Atlantic Meridional Overturning Circulation (AMOC) and North Atlantic SSTs. A weakening of the Agulhas Leakage therefore could transmit changes in the southern hemisphere to the northern hemisphere. Much of the Agulhas leakage is carried in small eddies rotating off the main flow south of Cape Horn. High ocean model resolution (< 1/2°) is therefore required to realistically simulate the leakage's response to the overlying wind field. Here we run a series of global high-resolution ocean model (1/6°) experiments using the MITgcm to test the effect of a shift in the southern hemisphere westerlies on the Agulhas Leakage, during a past climate (Pliocene) warmer than today. A prescribed perturbation of the winds near South Africa shows a significant increase in Agulhas eddies into the Atlantic. Following this, we have performed longer simulations (> 25 model years) on the simulated Pliocene Ocean reflecting past shifts in the wind field quantify changes in Agulhas Leakage transport and salinity anomalies into the South Atlantic. We then investigate whether there is any corresponding change in North Atlantic Deep Water formation and the overall response of

  2. Submicrosecond characteristics of lightning return-stroke currents

    NASA Technical Reports Server (NTRS)

    Leteinturier, Christiane; Hamelin, Joel H.; Eybert-Berard, Andre

    1991-01-01

    The authors describe the experimental results obtained during 1987 and 1988 triggered-lightning experiments in Florida. Seventy-four simultaneous submicrosecond time-resolved measurements of triggered return-stroke current (I) and current derivative (dI/dt) were made in Florida in 1987 and 1988. Peak currents ranged from about 5 to 76 kA, peak dI/dt amplitude from 13 to 411 kA/microsec and rise time from 90 to 1000 ns. The mean peak dI/dt values of 110 kA/microsec were 2-3 times higher than data from instrumented towers and peak I and dI/dt appear to be positively correlated. These data confirm previous experiments and conclusions supported by forty measurements. They are important in order to define, for example, standards for lightning protection. Present standards give a dI/dt maximum of 140 kA/microsec.

  3. RETURN CURRENTS AND ENERGY TRANSPORT IN THE SOLAR FLARING ATMOSPHERE

    SciTech Connect

    Codispoti, Anna; Torre, Gabriele; Piana, Michele; Pinamonti, Nicola

    2013-08-20

    According to the standard Ohmic perspective, the injection of accelerated electrons into the flaring region violates local charge equilibrium and therefore, in response, return currents are driven by an electric field to equilibrate such charge violation. In this framework, the energy loss rate associated with these local currents has an Ohmic nature and significantly shortens the accelerated electron path. In the present paper, we adopt a different viewpoint and, specifically, we study the impact of the background drift velocity on the energy loss rate of accelerated electrons in solar flares. We first utilize the Rutherford cross-section to derive the formula of the energy loss rate when the collisional target has a finite temperature and the background instantaneously and coherently moves up to equilibrate the electron injection. We then use the continuity equation for electrons and imaging spectroscopy data provided by RHESSI to validate this model. We show that this new formula for the energy loss rate provides a better fit of the experimental data with respect to the model based on the effects of standard Ohmic return currents.

  4. Current trajectory options for a comet nucleus sample return mission

    NASA Astrophysics Data System (ADS)

    Sauer, Carl G., Jr.

    1992-08-01

    A summary of the current trajectory options available for the ESA comet nucleus sample return mission, Rosetta, is presented. These options include direct trajectories, delta-V-EGA trajectories using a Titan IV/Centaur launch vehicle with upgraded solid rocket motors, a trajectory involving a gravity assist of the earth (VEGA) prior to comet rendezvous, and one involving an additional gravity assist of the earth (VEEGA). Other propulsion options proposed and discussed are solar electric propulsion/ballistic trajectory modes and nuclear electric propulsion trajectory modes. Tables of performance data for each of these trajectory options are given.

  5. Advanced Curation: Solving Current and Future Sample Return Problems

    NASA Technical Reports Server (NTRS)

    Fries, M.; Calaway, M.; Evans, C.; McCubbin, F.

    2015-01-01

    Advanced Curation is a wide-ranging and comprehensive research and development effort at NASA Johnson Space Center that identifies and remediates sample related issues. For current collections, Advanced Curation investigates new cleaning, verification, and analytical techniques to assess their suitability for improving curation processes. Specific needs are also assessed for future sample return missions. For each need, a written plan is drawn up to achieve the requirement. The plan draws while upon current Curation practices, input from Curators, the analytical expertise of the Astromaterials Research and Exploration Science (ARES) team, and suitable standards maintained by ISO, IEST, NIST and other institutions. Additionally, new technologies are adopted on the bases of need and availability. Implementation plans are tested using customized trial programs with statistically robust courses of measurement, and are iterated if necessary until an implementable protocol is established. Upcoming and potential NASA missions such as OSIRIS-REx, the Asteroid Retrieval Mission (ARM), sample return missions in the New Frontiers program, and Mars sample return (MSR) all feature new difficulties and specialized sample handling requirements. The Mars 2020 mission in particular poses a suite of challenges since the mission will cache martian samples for possible return to Earth. In anticipation of future MSR, the following problems are among those under investigation: What is the most efficient means to achieve the less than 1.0 ng/sq cm total organic carbon (TOC) cleanliness required for all sample handling hardware? How do we maintain and verify cleanliness at this level? The Mars 2020 Organic Contamination Panel (OCP) predicts that organic carbon, if present, will be present at the "one to tens" of ppb level in martian near-surface samples. The same samples will likely contain wt% perchlorate salts, or approximately 1,000,000x as much perchlorate oxidizer as organic carbon

  6. Lightning Return-Stroke Current Waveforms Aloft, from Measured Field Change, Current, and Channel Geometry

    NASA Technical Reports Server (NTRS)

    Willett, J. C.; LeVine, D. M.; Idone, V. P.

    2006-01-01

    Three-dimensional reconstructions of six rocket-triggered lightning channels are derived from stereo photographs. These reconstructed channels are used to infer the behavior of the current in return strokes above the ground from current waveforms measured at the channel base and electric-field-change waveforms measured at a range of 5.2 kilometers for 24 return strokes in these channels. Streak photographs of 14 of the same strokes are analyzed to determine the rise times, propagation speeds, and amplitudes of relative light intensity for comparison with the electrical inferences. Results include the following: 1) The fine structure of the field-change waveforms that were radiated by these subsequent return strokes can be explained, in large part, by channel geometry. 2) The average 10 - 90% rise time of the stroke current increased by about a factor of seven in our sample, from an observed 0.31 plus or minus 0.17 microseconds at the surface to an inferred 2.2 plus or minus 0.5 microcseconds at 1 kilometer path length above the surface. 3) The three-dimensional propagation speed of the current front averaged 1.80 plus or minus 0.24 X 10(exp 8) meters per second over channel lengths typically greater than 1 kilometer. 4) Assuming that the measured current was entirely due to the return stroke forced an unreasonably large and abrupt reduction in inferred current amplitude over the first few tens of meters above the surface, especially in cases when the leader was bright relative to its stroke. Therefore, a significant fraction of the current at the surface was probably due to the leader, at least in such cases. 5) Peak return-stroke currents decreased by approximately 37 plus or minus 12% from 100 meters to 1 kilometer of path length above the surface. Because of uncertainty about how to partition the measured current between leader and return stroke, we are unable to infer the variation of current amplitude near the ground.

  7. Return Current Electron Beams and Their Generation of "Raman" Scattering

    NASA Astrophysics Data System (ADS)

    Simon, A.

    1998-11-01

    For some years, we(A. Simon and R. W. Short, Phys. Rev. Lett. 53), 1912 (1984). have proposed that the only reasonable explanation for many of the observations of "Raman" scattering is the presence of an electron beam in the plasma. (The beam creates a bump-on-tail instability.) Two major objections to this picture have been observation of Raman when no n_c/4 surface was present, with no likely source for the electron beam, and the necessity for the initially outward directed beam to bounce once to create the proper waves. Now new observations on LLE's OMEGA(R. Petrasso et al), this conference. and at LULI(C. Labaune et al)., Phys. Plasma 5, 234 (1998). have suggested a new origin for the electron beam. This new scenario answers the previous objections, maintains electron beams as the explanation of the older experiments, and may clear up puzzling observations that have remained unexplained. The new scenario is based on two assumptions: (1) High positive potentials develop in target plasmas during their creation. (2) A high-intensity laser beam initiates spark discharges from nearby surfaces to the target plasma. The resulting return current of electrons should be much more delta-like, is initially inwardly directed, and no longer requires the continued presence of a n_c/4 surface. Scattering of the interaction beam from the BOT waves yields the observed Raman signal. Experimental observations that support this picture will be cited. ``Pulsation'' of the scattering and broadband ``flashes'' are a natural part of this scenario. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460.

  8. Lightning Return-Stroke Current Waveforms Aloft, From Measured Field Change, Current, and Channel Geometry

    NASA Technical Reports Server (NTRS)

    Willett, J. C.; LeVine, D. M.

    2002-01-01

    Direct current measurements are available near the attachment point from both natural cloud-to-ground lightning and rocket-triggered lightning, but little is known about the rise time and peak amplitude of return-stroke currents aloft. We present, as functions of height, current amplitudes, rise times, and effective propagation velocities that have been estimated with a novel remote-sensing technique from data on 24 subsequent return strokes in six different lightning flashes that were triggering at the NASA Kennedy Space Center, FL, during 1987. The unique feature of this data set is the stereo pairs of still photographs, from which three-dimensional channel geometries were determined previously. This has permitted us to calculate the fine structure of the electric-field-change (E) waveforms produced by these strokes, using the current waveforms measured at the channel base together with physically reasonable assumptions about the current distributions aloft. The computed waveforms have been compared with observed E waveforms from the same strokes, and our assumptions have been adjusted to maximize agreement. In spite of the non-uniqueness of solutions derived by this technique, several conclusions seem inescapable: 1) The effective propagation speed of the current up the channel is usually significantly (but not unreasonably) faster than the two-dimensional velocity measured by a streak camera for 14 of these strokes. 2) Given the deduced propagation speed, the peak amplitude of the current waveform often must decrease dramatically with height to prevent the electric field from being over-predicted. 3) The rise time of the current wave front must always increase rapidly with height in order to keep the fine structure of the calculated field consistent with the observations.

  9. Exceptional Agulhas leakage prolonged interglacial warmth during MIS 11c in Europe

    NASA Astrophysics Data System (ADS)

    Koutsodendris, Andreas; Pross, Jörg; Zahn, Rainer

    2014-11-01

    The transport of warm and saline surface water from the Indo-Pacific Ocean into the South Atlantic ("Agulhas leakage") influences the Atlantic Meridional Overturning Circulation (AMOC), which in turn exerts control on European climate. Paleoceanographic data document a remarkably strong Agulhas leakage at the end of marine isotope stage (MIS) 11c interglacial (~400 ka B.P.), which is one of the best orbital analogues for the Holocene. Here we assess the potential influence of this exceptional Agulhas leakage on North Atlantic climate based on a compilation of marine and terrestrial proxy records from the Iberian margin and continental Europe. We show that a ~5 ka long warm period persisted across Europe beyond the MIS 11c climatic optimum. This warm period is testified by increases in foraminifer-derived sea surface temperatures on the Iberian margin, a spread of temperate trees on Iberia, and the expansion both of evergreen trees and thermophilous diatom taxa in Central European lowlands. Paradoxically, this warming coincides with an insolation minimum, implying that orbital forcing can be excluded as the underlying cause. We conclude that persistent warmth during weak insolation at the end of MIS 11c in Europe may have been triggered by strengthened Agulhas leakage, which stimulated a vigorous AMOC and increased the northward transport of warm surface waters to higher latitudes via the North Atlantic Current. The close analogy of the present and MIS 11c orbital forcing underlines the possibility that the present-day increase of the Agulhas leakage, although driven by different forcing than MIS 11c, may considerably affect future climates across Europe.

  10. Atlantic multi-decadal oscillation covaries with Agulhas leakage

    PubMed Central

    Biastoch, Arne; Durgadoo, Jonathan V.; Morrison, Adele K.; van Sebille, Erik; Weijer, Wilbert; Griffies, Stephen M.

    2015-01-01

    The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, ‘Agulhas leakage', forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870–2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. This is relevant for climate in the North Atlantic. PMID:26656850

  11. Atlantic multi-decadal oscillation covaries with Agulhas leakage

    SciTech Connect

    Biastoch, Arne; Durgadoo, Jonathan V.; Morrison, Adele K.; van Sebille, Erik; Weijer, Wilbert; Griffies, Stephen M.

    2015-12-10

    The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, ‘Agulhas leakage’, forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870–2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. Lastly, this is relevant for climate in the North Atlantic.

  12. Atlantic multi-decadal oscillation covaries with Agulhas leakage.

    PubMed

    Biastoch, Arne; Durgadoo, Jonathan V; Morrison, Adele K; van Sebille, Erik; Weijer, Wilbert; Griffies, Stephen M

    2015-12-10

    The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, 'Agulhas leakage', forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870-2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. This is relevant for climate in the North Atlantic.

  13. Return stroke velocities and currents using a solid state silicon detector system

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Rust, W. David

    1988-01-01

    A small, portable device has been developed to measure return stroke velocities. With the device, velocities from 135 strokes that consist of 92 natural return strokes and 43 triggered return strokes have been analyzed. The average return stroke velocity for longer channels, greater than 500 meters, is 1.2 + or - 0.3 x 10 to the 8th m/s for both natural and triggered return strokes. For shorter channel lengths, less than 500 m, natural lightning has a statistically higher average return stroke velocity of 1.9 + or - 0.7 x 10 to the 8th m/s than triggered lightning with an average return stroke velocity of 1.4 + or - 0.4 x 10 to the 8th m/s. Using the transmission line model of the return stroke, natural lightning has a peak current distribution that is log-normal with a median value of 19 kA. Return stroke velocities and currents were determined for two distant single stroke natural positive cloud-to-ground flashes. The velocities were 1.0 and 1.7 x 10 to the 8th ms/s while the estimated peak current for each positive flash was over 125 kA.

  14. Mechanisms of nearshore retention and offshore export of mussel larvae over the Agulhas Bank

    NASA Astrophysics Data System (ADS)

    Weidberg, Nicolás; Porri, Francesca; Von der Meden, Charles E. O.; Jackson, Jennifer M.; Goschen, Wayne; McQuaid, Christopher D.

    2015-04-01

    Ecological connectivity is critical for population dynamics but in many benthic species it is complicated by a planktonic larval phase, whose dispersal remains poorly understood. Using a plankton pump, we examine the distribution of intertidal mussel larvae along three axes: alongshore, cross-shelf and by depth during a large scale (600 km) cruise over the Agulhas Bank off southern Africa in August/September 2010. As a general pattern, higher veliger abundances were found close to the coast. Our analyses of the nearshore flow, estimated from ADCP data and the vertical distribution of larvae, show that onshore larval retention may be mediated by active vertical swimming through the water column guided by light and wind-induced turbulence. A massive offshore export of larvae off St Francis Bay was, however, observed during an Agulhas Current meander which influenced inner shelf waters. We hypothesize that, by increasing and homogenizing flow, the Agulhas Current may erase the effects of larval vertical positioning on onshore retention and transport larvae offshore. Our study highlights the need to integrate the effects of complex, region-specific physical dynamics with the swimming behaviour of larvae in order to explain their spatial distribution, population connectivity and the consequences for population dynamics.

  15. Numerical Solution for the Determination of Towboat Return Currents

    DTIC Science & Technology

    1994-03-01

    Numerical Solution of Potential Flow ...................... 7 Geometry and Grid Development ........................ 7 Boundaries...and size of the hull, and the channel geometry . h. Wake flow . The current produced as water fills in behind the stern to replace the water displaced...time-steps). Geometry and Grid Development Sensitivity tests were conducted using STREMR to determine the potential of modeling the flow field around

  16. The Impact of Return-Current Losses on the Observed Emissions from Solar Flares

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.

    2011-01-01

    Electrons accelerated in solar flares are expected to drive a co-spatial return current in the ambient plasma when they escape the acceleration region. This return current maintains plasma neutrality and the stability of the beam of streaming electrons. The electric field that drives this return current also decelerates the energetic electrons in the beam. The corresponding energy loss experienced by the accelerated electrons can affect the observed properties of the X-ray and radio emissions from flares and the evolution of the thermal flare plasma. I will discuss the properties of the flare emissions expected in a classical, steady-state model. As part of this discussion, I will examine Gordon Emslie's 1980 conjecture that return-current losses result in a maximum brightness for the hard X-ray emission from flares.

  17. Influence of channel base current and varying return stroke speed on the calculated fields of three important return stroke models

    NASA Technical Reports Server (NTRS)

    Thottappillil, Rajeev; Uman, Martin A.; Diendorfer, Gerhard

    1991-01-01

    Compared here are the calculated fields of the Traveling Current Source (TCS), Modified Transmission Line (MTL), and the Diendorfer-Uman (DU) models with a channel base current assumed in Nucci et al. on the one hand and with the channel base current assumed in Diendorfer and Uman on the other hand. The characteristics of the field wave shapes are shown to be very sensitive to the channel base current, especially the field zero crossing at 100 km for the TCS and DU models, and the magnetic hump after the initial peak at close range for the TCS models. Also, the DU model is theoretically extended to include any arbitrarily varying return stroke speed with height. A brief discussion is presented on the effects of an exponentially decreasing speed with height on the calculated fields for the TCS, MTL, and DU models.

  18. Characterization of return-stroke currents in rocket-triggered lightning

    NASA Astrophysics Data System (ADS)

    Schoene, J.; Uman, M. A.; Rakov, V. A.; Rambo, K. J.; Jerauld, J.; Mata, C. T.; Mata, A. G.; Jordan, D. M.; Schnetzer, G. H.

    2009-02-01

    We present a statistical analysis of the salient characteristics of current waveforms for 206 return strokes in 46 rocket-triggered lightning flashes. The flashes were triggered during a variety of experiments related to the interaction of lightning with power lines that were conducted from 1999 through 2004 at the International Center for Lightning Research and Testing at Camp Blanding, Florida. The return-stroke current, after measurement, was injected into either one of two test power lines or into the Earth near a power line via a grounding system of the rocket launcher. Statistical information is presented for return-stroke peak current, charge transfer, half-peak width, and 10%-90% risetime. Our return-stroke peak current statistics are found to be generally consistent with those reported from other triggered-lightning studies and appear to be independent of electrical properties of the strike object, as previously found in another study. We found significant correlation (R2 = 0.76) between lightning return-stroke peak current and the corresponding charge transfer within 1 ms after return-stroke initiation. The dependence is surprisingly similar to that found by Berger and co-workers for the natural first return-stroke peak currents and 1-ms charge transfers. The means of the 10%-90% current risetimes for strikes to the power line (geometric mean 1.2 μs) and for strikes to the Earth (geometric mean 0.4 μs) are significantly different which indicates that the electrical properties of the strike object affect the risetime. This effect is likely related to the impedance seen by lightning at the strike point and/or to reflections at impedance discontinuities within the strike object, larger effective impedances apparently resulting in larger risetimes. A dependence of the return-stroke current half-peak width on the electrical properties of the strike object was not observed in our direct and nearby-strike experiments.

  19. Resistivity and anisotropic return currents in warm dense plasmas

    NASA Astrophysics Data System (ADS)

    Woolsey, Nigel; Booth, Nicola; Robinson, A.; Hakel, P.; Clarke, R.; Dance, R.; Doia, D.; Gizzi, L.; Gregori, G.; Koester, P.; Labate, L.; Li, B.; Makita, M.; Mancini, R.; Pasley, J.; Rajeev, P.; Riley, D.; Wagenaars, E.; Waugh, J.

    2015-11-01

    In an ultra-intense laser interaction with a solid, the electrons from the hot plasma are accelerated by the laser streaming into the solid behind, creating a dense plasma in the bulk. This provides a laboratory for creating warm dense matter in a parameter range where the material resistivity and equation of states are complex and mostly untested. Here we describe an experimental study of electron transport in a low atomic number (plastic) material at solid density and temperatures of 200 eV. The plastic is doped with sulphur as a diagnostic tracer to enable the observation of emission spectra. Through observing high positive polarisation in this emission it is possible to infer in situ anisotropic currents driving the heat transport. Matching the current anisotropy enables tests of resistivity models in these complex plasmas. Results show that the background resistivity at these conditions is high than expected from commonly used models.

  20. Photoelectric return-stroke velocity and peak current estimates in natural and triggered lightning

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Rust, W. David

    1989-01-01

    Two-dimensional photoelectric return stroke velocities from 130 strokes are presented, including 86 negative natural, 41 negative triggered, one positive triggered, and two positive natural return strokes. For strokes starting near the ground and exceeding 500 m in length, the average velocity is 1.3 + or - 0.3 X 10 to the 8th m/s for natural return strokes and 1.2 + or - 0.3 X 10 to the 8th m/s for triggered return strokes. For strokes with lengths less than 500 m, the average velocities are slightly higher. Using the transmission line model (TLM), the shortest segment one-dimensional return stroke velocity, and either the maximum or plateau electric field, it is shown that natural strokes have a peak current distribution that is lognormal with a median value of 16 kA (maximum E) or 12 kA (plateau E). Triggered lightning has a medium peak current value of 21 kA (maximum E) or 15 kA (plateau E). Correlations are found between TLM peak currents and velocities for triggered and natural subsequent return strokes, but not between TLM peak currents and natural first return stroke velocities.

  1. Fast initial continuous current pulses versus return stroke pulses in tower-initiated lightning

    NASA Astrophysics Data System (ADS)

    Azadifar, Mohammad; Rachidi, Farhad; Rubinstein, Marcos; Rakov, Vladimir A.; Paolone, Mario; Pavanello, Davide; Metz, Stefan

    2016-06-01

    We present a study focused on pulses superimposed on the initial continuous current of upward negative discharges. The study is based on experimental data consisting of correlated lightning current waveforms recorded at the instrumented Säntis Tower in Switzerland and electric fields recorded at a distance of 14.7 km from the tower. Two different types of pulses superimposed on the initial continuous current were identified: (1) M-component-type pulses, for which the microsecond-scale electric field pulse occurs significantly earlier than the onset of the current pulse, and (2) fast pulses, for which the onset of the field matches that of the current pulse. We analyze the currents and fields associated with these fast pulses (return-stroke type (RS-type) initial continuous current (ICC) pulses) and compare their characteristics with those of return strokes. A total of nine flashes containing 44 RS-type ICC pulses and 24 return strokes were analyzed. The median current peaks associated with RS-type ICC pulses and return strokes are, respectively, 3.4 kA and 8 kA. The associated median E-field peaks normalized to 100 km are 1.5 V/m and 4.4 V/m, respectively. On the other hand, the electric field peaks versus current peaks for the two data sets (RS-type ICC pulses and return strokes) are characterized by very similar linear regression slopes, namely, 3.67 V/(m kA) for the ICC pulses and 3.77 V/(m kA) for the return strokes. Assuming the field-current relation based on the transmission line model, we estimated the apparent speed of both the RS-type ICC pulses and return strokes to be about 1.4 × 108 m/s. A strong linear correlation is observed between the E-field risetime and the current risetime for the ICC pulses, similar to the relation observed between the E-field risetime and current risetime for return strokes. The similarity of the RS-type ICC pulses with return strokes suggests that these pulses are associated with the mixed mode of charge transfer to ground.

  2. Gas-puff liner implosion in the configuration with helical current return rods

    SciTech Connect

    Sorokin, S. A.

    2013-02-15

    Results of experiments with double-shell gas-puff liners carried out on a high-current MIG generator (2 MA, 80 ns) are presented. To stabilize the process of liner implosion and increase the efficiency of energy transfer from the generator to the liner plasma, a current return in the form of a multifilar helix was used. The effect of the configuration of the current return on the parameters of the generated pulses of argon and neon K-shell radiation (with photon energies of 3-5 and 0.9-1.5 keV, respectively) and the neutron yield from a deuterium liner were studied.

  3. Two-dimensional velocity, optical risetime, and peak current estimates for natural positive lightning return strokes

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Rust, W. D.

    1993-01-01

    Velocities, optical risetimes, and transmission line model peak currents for seven natural positive return strokes are reported. The average 2D positive return stroke velocity for channel segments of less than 500 m in length starting near the base of the channel is 0.8 +/- 0.3 x 10 exp 8 m/s, which is slower than the present corresponding average velocity for natural negative first return strokes of 1.7 +/- 0.7 x 10 exp 8/s. It is inferred that positive stroke peak currents in the literature, which assume the same velocity as negative strokes, are low by a factor of 2. The average 2D positive return stroke velocity for channel segments of greater than 500 m starting near the base of the channel is 0.9 +/- 0.4 x 10 exp 8 m/s. The corresponding average velocity for the present natural negative first strokes is 1.2 +/- 0.6 x 10 exp 8 m/s. No significant velocity change with height is found for positive return strokes.

  4. Identifying Return-Current Losses in Flare Hard X-ray Spectra

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.

    2011-01-01

    I will report on theoretical studies and a data analysis program aimed at identifying and physically interpreting breaks in hard X-ray spectra resulting from return-current energy losses, as well as heating of the flare plasma resulting from these losses.

  5. Reduction of Return Current Noise Using Double-Series Resonant Filter

    NASA Astrophysics Data System (ADS)

    Azuma, Satoshi; Itoh, Daisuke; Sugahara, Kengo

    A novel double-series resonant filter is implemented in order to reduce the high-frequency return current noise generated by AC-powered electric cars with AC/DC PWM converters and inverters. The double-series resonant filter is placed between a main transformer and a converter. The resonant filter is tuned so that the noise signal due to the return current is attenuated at the exact noise frequency; for example, the 105-kHz component of an ATS (Automatic Train Stop) signal is attenuated by this filter. The filter has two LCR resonant circuits, one of which is in parallel with a resistance. This filter design helps achieve good attenuation at the noise frequency and helps limit unnecessary amplification at other frequencies. First, a test filter is realized, and the inductance and capacitance of this filter are in good agreement with the corresponding values in the filter design. Then, the filter is included in a full-scale test system with a main transformer and a converter. Then it is confirmed that a 5-dB reduction in the return current noise is achieved by using the proposed filter. Finally, the return current noise in the test system is confirmed to be well below the desired regulation level. This is expected to help realize simple methods for dealing with the effects of impedance at high frequencies in the main transformer.

  6. Return current effects in passive plasma lenses for relativistic electron beams

    NASA Astrophysics Data System (ADS)

    Govil, Richa

    This thesis presents results of an experimental study of return currents effects on beam focusing in plasma lenses conducted at the Beam Test Facility (BTF) at Lawrence Berkeley National Laboratory (LBNL). Relativistic electron beams can be focused in field-free plasmas due to magnetic self-pinching. However, plasma return currents induced by the changing magnetic flux of a propagating bunch can reduce the total magnetic field and focusing force (Ampere's law). The experiment covered a parameter regime not observed previously, namely, the return current regime, where the collisionless plasma skindepth is small compared to the electron beam size and the focusing strength of the plasma lens is reduced due to return currents. A relativistic electron beam from the BTF, which utilizes the Advanced Light Source (ALS) injector, was used to study the properties of return currents in plasmas. The beam-transport line and experimental chamber were designed to allow measurement of electron beam size continuously along its path, before and after it passed through plasma lenses. For this purpose, an optical transition radiation (OTR) based diagnostic was developed. To ensure plasmas free of external fields, laser- ionization was chosen as the plasma production method. The dependence of plasma density on fill pressure and laser intensity was studied with an in-quadrature Mach- Zehnder radio frequency interferometer. A novel interferometry technique based on evanescent wave detection was developed to measure plasma densities above the cutoff density, for plasmas with a thickness less than the collisionless skin depth. Plasma density was controlled by changing the fill-pressure in the chamber, while the plasma profile was adjusted through the laser intensity. For typical experimental parameters, the electron beam size was observed to reduce in the presence of plasma. Plasma lenses were produced in the return current regime with the ratio of beam size to collisionless plasma

  7. NLDN Performance Characteristics for Return Strokes and Pulses Superimposed on Steady Currents

    NASA Astrophysics Data System (ADS)

    Mallick, S.; Rakov, V. A.; Hill, J. D.; Ngin, T.; Gamerota, W. R.; Pilkey, J. T.; Jordan, D. M.; Uman, M. A.; Cramer, J. A.

    2012-12-01

    Jerauld et al. (2005) and Nag et al. (2011) evaluated the performance characteristic of the U.S. National Lightning Detection Network (NLDN) by comparing NLDN data with the corresponding ground-truth data for lightning triggered at Camp Blanding (CB), Florida. Their results are thought to be applicable to subsequent return strokes in natural downward lightning. Besides return strokes, the NLDN is capable of recording sufficiently large pulses superimposed on steady currents occurring during the initial stage of rocket-triggered or object-initiated lightning, as well as on those following some return-stroke pulses in both downward and upward flashes. The NLDN performance characteristics for such superimposed pulses are presently unknown. In this paper, we extend the studies of Jerauld et al. (2005) and Nag et al. (2011) using additional ground-truth data for CB triggered lightning. The new data set covers the period from 2004 to 2012 (9 years after the last major NLDN upgrade). The data set includes "classical" return strokes, generally preceded by "zero-current" (less than 1 A) intervals and kiloampere-scale pulses (with amplitudes equal to or greater than 1 kA) superimposed on steady currents (initial-stage pulses and M-components). Fisher et al. (1993) found that triggered-lightning return strokes were invariably preceded by a time interval without measurable current flowing to ground (the minimum detectable current level was less than 2 A), implying that a complete cutoff in channel current is a prerequisite for the formation of a subsequent leader/return stroke sequence. This finding is consistent with the observations of McCann (1944) and Berger (1967) who reported that the current between strokes fell below their systems' minimum detectable levels of 0.1 A and 1 A, respectively. On the other hand, "classical" M-components and some of the initial-stage pulses develop along channel sections, a kilometer or more in length, that carry steady currents, typically

  8. Correlated peak relative light intensity and peak current in triggered lightning subsequent return strokes

    NASA Technical Reports Server (NTRS)

    Idone, V. P.; Orville, R. E.

    1985-01-01

    The correlation between peak relative light intensity L(R) and stroke peak current I(R) is examined for 39 subsequent return strokes in two triggered lightning flashes. One flash contained 19 strokes and the other 20 strokes for which direct measurements were available of the return stroke peak current at ground. Peak currents ranged from 1.6 to 21 kA. The measurements of peak relative light intensity were obtained from photographic streak recordings using calibrated film and microsecond resolution. Correlations, significant at better than the 0.1 percent level, were found for several functional relationships. Although a relation between L(R) and I(R) is evident in these data, none of the analytical relations considered is clearly favored. The correlation between L(R) and the maximum rate of current rise is also examined, but less correlation than between L(R) and I(R) is found. In addition, the peak relative intensity near ground is evaluated for 22 dart leaders, and a mean ratio of peak dart leader to peak return stroke relative light intensity was found to be 0.1 with a range of 0.02-0.23. Using two different methods, the peak current near ground in these dart leaders is estimated to range from 0.1 to 6 kA.

  9. JSC Advanced Curation: Research and Development for Current Collections and Future Sample Return Mission Demands

    NASA Technical Reports Server (NTRS)

    Fries, M. D.; Allen, C. C.; Calaway, M. J.; Evans, C. A.; Stansbery, E. K.

    2015-01-01

    Curation of NASA's astromaterials sample collections is a demanding and evolving activity that supports valuable science from NASA missions for generations, long after the samples are returned to Earth. For example, NASA continues to loan hundreds of Apollo program samples to investigators every year and those samples are often analyzed using instruments that did not exist at the time of the Apollo missions themselves. The samples are curated in a manner that minimizes overall contamination, enabling clean, new high-sensitivity measurements and new science results over 40 years after their return to Earth. As our exploration of the Solar System progresses, upcoming and future NASA sample return missions will return new samples with stringent contamination control, sample environmental control, and Planetary Protection requirements. Therefore, an essential element of a healthy astromaterials curation program is a research and development (R&D) effort that characterizes and employs new technologies to maintain current collections and enable new missions - an Advanced Curation effort. JSC's Astromaterials Acquisition & Curation Office is continually performing Advanced Curation research, identifying and defining knowledge gaps about research, development, and validation/verification topics that are critical to support current and future NASA astromaterials sample collections. The following are highlighted knowledge gaps and research opportunities.

  10. Ocean-Atmosphere Interaction Over Agulhas Extension Meanders

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Xie, Xiaosu; Niiler, Pearn P.

    2007-01-01

    Many years of high-resolution measurements by a number of space-based sensors and from Lagrangian drifters became available recently and are used to examine the persistent atmospheric imprints of the semi-permanent meanders of the Agulhas Extension Current (AEC), where strong surface current and temperature gradients are found. The sea surface temperature (SST) measured by the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) and the chlorophyll concentration measured by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) support the identification of the meanders and related ocean circulation by the drifters. The collocation of high and low magnitudes of equivalent neutral wind (ENW) measured by Quick Scatterometer (QuikSCAT), which is uniquely related to surface stress by definition, illustrates not only the stability dependence of turbulent mixing but also the unique stress measuring capability of the scatterometer. The observed rotation of ENW in opposition to the rotation of the surface current clearly demonstrates that the scatterometer measures stress rather than winds. The clear differences between the distributions of wind and stress and the possible inadequacy of turbulent parameterization affirm the need of surface stress vector measurements, which were not available before the scatterometers. The opposite sign of the stress vorticity to current vorticity implies that the atmosphere spins down the current rotation through momentum transport. Coincident high SST and ENW over the southern extension of the meander enhance evaporation and latent heat flux, which cools the ocean. The atmosphere is found to provide negative feedback to ocean current and temperature gradients. Distribution of ENW convergence implies ascending motion on the downwind side of local SST maxima and descending air on the upwind side and acceleration of surface wind stress over warm water (deceleration over cool water); the convection may escalate the contrast of

  11. Changes in Measured Lightning Return Stroke Peak Current After the 1994 National Lightning Detection Network Upgrade

    DTIC Science & Technology

    2011-07-28

    dt, we see that a changing magnetic flux, (D, through a current loop produces an electromotive force, e, in the loop (Griffiths 1989). Two orthogonal...effects are the source of the noisiness of actual return stroke radiation. They suggest that the channel can be represented by a series of randomly...monitor as a user interface and a color monitor to display graphical results. FLASH can be used to produce scatter plots, time series , and contours of

  12. Where Three Oceans Meet: The Agulhas Retroflection Region

    DTIC Science & Technology

    1988-10-01

    Agulhas Retroflection Region by Sara Louise Bennett B.S. Colorado State University, Fort Collins, Colorado 1977 SUBMITED IN PARTIAL FULFILLMENT OF THE...As children we read Rachel Carson’s Silent Spring (1962) and, as teenagers, the Club of Rome’s Limits to Growth (1974). We know that critical natural...and Amnesty International Group 77 of Falmouth for keeping me connected with the real world outside the ivory tower. Donna Carson and Vicki Cullen

  13. Return current and proton emission from wire targets interacting with an intense short pulse laser

    NASA Astrophysics Data System (ADS)

    Beg, Farhat

    2004-05-01

    One of the important characteristics of short pulse high intensity laser-solid interactions is the generation of energetic charged particles, which result from the very efficient conversion of laser energy into hot electrons. Since the electrons in the electric field of the laser have relativistic quiver motions, the temperature of the hot electron distribution of the plasma produced at such extreme intensities can become very high. A large number of hot electrons (1013-1014) having an average energy of the order of 1-2 MeV can be generated as intensities exceed 1019 Wcm-2. Since the resulting beam current exceeds the Alfvén limit, a neutralizing return current of cold plasma electrons moving in the opposite direction is produced. Another source of return current is that due to the escape of very energetic electrons from the target, which then creates a large electrostatic potential due to charge separation. These return currents can cause significant ohmic heating. In addition escaping electrons establish the large electrostatic fields, accelerating a large number of protons from the target with energies of 10's of MeV. The experiments reported here were performed at the Rutherford Appleton Laboratory with the VULCAN laser facility at intensity greater than 5 x1019 Wcm-2 on wire targets. In some shots an additional wire or foil was placed nearby. The laser was blocked by the main wire target so that no laser light reached the additional wire or foil. Three main observations were made: (i) a Z-pinch was driven in the wire due to the return current, (ii) optical transition radiation (OTR) at 2w was generated and (iii) energetic proton emission was observed. The wire targets were observed to be ohmically heated and were m=0 unstable. The OTR emission is likely due to electron bunches accelerated by the ponderomotive force of the laser. The proton emission was in a form of thin disk perpendicular to the wire and centered on the wire at the laser focus. Proton

  14. Electron Beam Return-Current Losses in Solar Flares: Initial Comparison of Analytical and Numerical Results

    NASA Technical Reports Server (NTRS)

    Holman, Gordon

    2010-01-01

    Accelerated electrons play an important role in the energetics of solar flares. Understanding the process or processes that accelerate these electrons to high, nonthermal energies also depends on understanding the evolution of these electrons between the acceleration region and the region where they are observed through their hard X-ray or radio emission. Energy losses in the co-spatial electric field that drives the current-neutralizing return current can flatten the electron distribution toward low energies. This in turn flattens the corresponding bremsstrahlung hard X-ray spectrum toward low energies. The lost electron beam energy also enhances heating in the coronal part of the flare loop. Extending earlier work by Knight & Sturrock (1977), Emslie (1980), Diakonov & Somov (1988), and Litvinenko & Somov (1991), I have derived analytical and semi-analytical results for the nonthermal electron distribution function and the self-consistent electric field strength in the presence of a steady-state return-current. I review these results, presented previously at the 2009 SPD Meeting in Boulder, CO, and compare them and computed X-ray spectra with numerical results obtained by Zharkova & Gordovskii (2005, 2006). The phYSical significance of similarities and differences in the results will be emphasized. This work is supported by NASA's Heliophysics Guest Investigator Program and the RHESSI Project.

  15. Eddy Surface properties and propagation at Southern Hemisphere western boundary current systems

    NASA Astrophysics Data System (ADS)

    Pilo, G. S.; Mata, M. M.; Azevedo, J. L. L.

    2015-02-01

    Oceanic eddies occur in all world oceans, but are more energetic when associated to western boundary currents (WBC) systems. In these regions, eddies play an important role on mixing and energy exchange. Therefore, it is important to quantify and qualify eddies occurring within these systems. Previous studies performed eddy censuses in Southern Hemisphere WBC systems. However, important aspects of local eddy population are still unknown. Main questions to be answered relate to eddies' spatial distribution, propagation and lifetime within each system. Here, we use a global eddy dataset to qualify eddies based on their surface characteristics at the Agulhas Current (AC), the Brazil Current (BC) and the East Australian Current (EAC) Systems. We show that eddy propagation within each system is highly forced by the local mean flow and bathymetry. In the AC System, eddy polarity dictates its propagation distance. BC system eddies do not propagate beyond the Argentine Basin, and are advected by the local ocean circulation. EAC System eddies from both polarities cross south of Tasmania, but only anticyclonics reach the Great Australian Bight. Eddies in all systems and from both polarities presented a geographical segregation according to size. Large eddies occur along the Agulhas Retroflection, the Agulhas Return Current, the Brazil-Malvinas Confluence and the Coral Sea. Small eddies occur in the systems southernmost domains. Understanding eddies' propagation helps to establish monitoring programs, and to better understand how these features would affect local mixing.

  16. Salinity changes in the Agulhas leakage area recorded by stable hydrogen isotopes of C37 alkenones during Termination I and II

    NASA Astrophysics Data System (ADS)

    Kasper, S.; van der Meer, M. T. J.; Mets, A.; Zahn, R.; Sinninghe Damsté, J. S.; Schouten, S.

    2014-02-01

    At the southern tip of Africa, the Agulhas Current reflects back into the Indian Ocean causing so-called "Agulhas rings" to spin off and release relatively warm and saline water into the South Atlantic Ocean. Previous reconstructions of the dynamics of the Agulhas Current, based on paleo-sea surface temperature and sea surface salinity proxies, inferred that Agulhas leakage from the Indian Ocean to the South Atlantic was reduced during glacial stages as a consequence of shifted wind fields and a northwards migration of the subtropical front. Subsequently, this might have led to a buildup of warm saline water in the southern Indian Ocean. To investigate this latter hypothesis, we reconstructed sea surface salinity changes using alkenone δD, and paleo-sea surface temperature using TEXH86 and UK'37, from two sediment cores (MD02-2594, MD96-2080) located in the Agulhas leakage area during Termination I and II. Both UK'37 and TEXH86 temperature reconstructions indicate an abrupt warming during the glacial terminations, while a shift to more negative δDalkenone values of approximately 14‰ during glacial Termination I and II is also observed. Approximately half of the isotopic shift can be attributed to the change in global ice volume, while the residual isotopic shift is attributed to changes in salinity, suggesting relatively high salinities at the core sites during glacials, with subsequent freshening during glacial terminations. Approximate estimations suggest that δDalkenone represents a salinity change of ca. 1.7-1.9 during Termination I and Termination II. These estimations are in good agreement with the proposed changes in salinity derived from previously reported combined planktonic Foraminifera δ18O values and Mg/Ca-based temperature reconstructions. Our results confirm that the δD of alkenones is a potentially suitable tool to reconstruct salinity changes independent of planktonic Foraminifera δ18O.

  17. The effect of beam-driven return current instability on solar hard X-ray bursts

    NASA Technical Reports Server (NTRS)

    Cromwell, D.; Mcquillan, P.; Brown, J. C.

    1986-01-01

    The problem of electrostatic wave generation by a return current driven by a small area electron beam during solar hard X-ray bursts is discussed. The marginal stability method is used to solve numerically the electron and ion heating equations for a prescribed beam current evolution. When ion-acoustic waves are considered, the method appears satisfactory and, following an initial phase of Coulomb resistivity in which T sub e/T sub i rise, predicts a rapid heating of substantial plasma volumes by anomalous ohmic dissipation. This hot plasma emits so much thermal bremsstrahlung that, contrary to previous expectations, the unstable beam-plasma system actually emits more hard X-rays than does the beam in the purely collisional thick target regime relevant to larger injection areas. Inclusion of ion-cyclotron waves results in ion-acoustic wave onset at lower T sub e/T sub i and a marginal stability treatment yields unphysical results.

  18. Linking Agulhas Leakage Variability and North Atlantic Climate MIS 1-5a

    NASA Astrophysics Data System (ADS)

    Dyez, K. A.; Zahn, R.; Hall, I. R.

    2014-12-01

    Agulhas leakage of warm, salty water from the Indian Ocean to the South Atlantic is suggested to have altered Atlantic meridional overturning and climate in the North Atlantic. One way to assess such linkages with North Atlantic climate variability is to examine the past Agulhas hydrography via high-resolution marine records from the Agulhas Bank slope. Here we present one such hydrographic estimate from the Agulhas Bank slope in the Atlantic sector of the Agulhas Corridor using planktic foraminiferal (Globigerinoides ruber) δ18O and Mg/Ca-derived SST to estimate surface salinity. By focusing on the last 80,000 years this is the first quantitative fine-scale Agulhas leakage record that overlaps in time with the Greenland ice core record of abrupt climate changes in the North Atlantic region. Periods of enhanced Agulhas Corridor salinity occur at Northern Hemisphere cool periods (glacial termination and Heinrich meltwater events) and are followed by rapid northern hemisphere warming. We show that the timing of maximal salinity events in relation to periods of North Atlantic freshwater perturbation is consistent with the concept suggested by climate models that Agulhas salinity oscillations could provide buoyancy compensation for the Atlantic and potentially even trigger increased convective activity in the North Atlantic, thereby restoring Atlantic overturning circulation after relatively weak states.

  19. Coronal vs chromospheric heating through co-spatial return currents during the 19 and 20 Jan 2005 solar flare

    NASA Astrophysics Data System (ADS)

    Alaoui, Meriem; Holman, Gordon D.

    2016-05-01

    The high electron flux required to explain the bremsstrahlung X-ray emission observed from solar flares is expected to be accompanied by a neutralizing co-spatial return current. In addition to resupplying the acceleration region with electrons, this return current will both heat the coronal plasma and flatten the electron distribution at lower energies. This flattening in the electron distribution in turn flattens the X-ray spectrum. We have found that return-current collisional thick-target model (RCCTTM) of Holman (2012) provides an acceptable fit to X-ray spectra with strong breaks for 18 flares observed with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). This is a 1D model similar to the collisional thick-target model (CTTM) with two additional assumptions: (1) electrons lose some of their energy through return current losses along their path to the thick target, where they lose all their remaining energy through Coulomb collisions; (2) the non-thermal beam is streaming in a warm target, which means that electrons will be thermalized at a non-zero energy. We assume this energy to be equal to the analytical value derived by Kontar et al. 2015. We show that return-current heating in the corona is about an order of magnitude higher than the heating at the footpoints at times during the flare.

  20. Experiments on current-driven three-dimensional ion sound turbulence. I - Return-current limited electron beam injection. II - Wave dynamics

    NASA Technical Reports Server (NTRS)

    Stenzel, R. L.

    1978-01-01

    Pulsed electron beam injection into a weakly collisional magnetized background plasma is investigated experimentally; properties of the electron beam and background plasma, as well as the low-frequency instabilities and wave dynamics, are discussed. The current of the injected beam closes via a field-aligned return current of background electrons. Through study of the frequency and wavenumber distribution, together with the electron distribution function, the low-frequency instabilities associated with the pulsed injection are identified as ion acoustic waves driven unstable by the return current. The frequency cut-off of the instabilities predicted from renormalized plasma turbulence theory, has been verified experimentally.

  1. Understanding the Impact of Return-Current Losses on the X-Ray Emission from Solar Flares

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.

    2012-01-01

    I obtain and examine the implications of one-dimensional analytic solutions for return-current losses on an initially power-law distribution of energetic electrons with a sharp low-energy cutoff in flare plasma with classical (collisional) resistivity. These solutions show, for example, that return-current losses are not sensitive to plasma density, but are sensitive to plasma temperature and the low energy cutoff of the injected nonthermal electron distribution. A characteristic distance from the electron injection site, x(sub rc), is derived. At distances less than x(sub rc) the electron flux density is not reduced by return-current losses, but plasma heating can be substantial in this region, in the upper, coronal part of the flare loop. Before the electrons reach the collisional thick-target region of the flare loop, an injected power-law electron distribution with a low-energy cutoff maintains that structure, but with a flat energy distribution below the cutoff energy, which is now determined by the total potential drop experienced by the electrons. Modifications due to the presence of collisional losses are discussed. I compare these results with earlier analytical results and with more recent numerical simulations. Emslie's 1980 conjecture that there is a maximum integrated X-ray source brightness on the order of 10(exp -15) photons per square centimeter per second per square centimeter is examined. I find that this is not actually a maximum brightness and its value is parameter dependent, but it is nevertheless a valuable benchmark for identifying return-current losses in hard X-ray spectra. I discuss an observational approach to identifying return-current losses in flare data, including identification of a return-current "bump" in X-ray light curves at low photon energies.

  2. Inter-comparison studies between high-resolution HYCOM simulation and observational data: The South Atlantic and the Agulhas leakage system

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Campos, E. J. D.; Giddy, I.; Santis, W.

    2016-07-01

    Statistical analyses and model-data inter-comparisons are performed to evaluate the model's ability to reproduce the dynamics in the upper layers (< 2000 m) of the South Atlantic ocean. Outputs of an eddy-resolving Ocean General Circulation Model (OGCM) are analyzed and compared with observed data. The model, a 1/12-degree, 22-layer implementation of the Hybrid Coordinate Ocean Model (HYCOM) to the South Atlantic, was forced with monthly-mean products from the NCEP Reanalysis for the period 1960 to 2010. The numerical experiment was capable to reproduce the large scale and the mesoscale dynamic in the South Atlantic and in the Agulhas region. The vertical structure is in agreement with in situ data, the model has lower skill when compared with PIRATA lower temperatures, and is able to capture the seasonal and annual variability in the tropical Atlantic. Furthermore, sensitive change until 2007 is clear in the vertical structure, at 4°N-38°W; 0°-35°W and 10°S-10°W, suggesting an important change in the stratification. The primary results concern a significant change in the decadal anomalies of the temperatures and salinity, which exhibit a warmer and saltier water in the southeastern Atlantic. Furthermore, linear trends found in the transport time-series in the North Brazil Current, and the South Equatorial Current were seen to correspond with increasing trends of the warmer water from the Agulhas Current into South Atlantic. The integrated transport during the period 1960-2010, shows an increase in westward changes in the large-scale circulation south of Africa are show in the negative trends indicate a widening of the "Agulhas gap" and increase in westward volume transport since 1980. It is therefore suggested that variability in the Agulhas System on the last two decades is affecting the dynamic in the South Atlantic, namely the temperature and the volume transport, reach the tropical region of the Atlantic.

  3. On the role of the Agulhas system in ocean circulation and climate.

    PubMed

    Beal, Lisa M; De Ruijter, Wilhelmus P M; Biastoch, Arne; Zahn, Rainer

    2011-04-28

    The Atlantic Ocean receives warm, saline water from the Indo-Pacific Ocean through Agulhas leakage around the southern tip of Africa. Recent findings suggest that Agulhas leakage is a crucial component of the climate system and that ongoing increases in leakage under anthropogenic warming could strengthen the Atlantic overturning circulation at a time when warming and accelerated meltwater input in the North Atlantic is predicted to weaken it. Yet in comparison with processes in the North Atlantic, the overall Agulhas system is largely overlooked as a potential climate trigger or feedback mechanism. Detailed modelling experiments--backed by palaeoceanographic and sustained modern observations--are required to establish firmly the role of the Agulhas system in a warming climate.

  4. Ocean plankton. Environmental characteristics of Agulhas rings affect interocean plankton transport.

    PubMed

    Villar, Emilie; Farrant, Gregory K; Follows, Michael; Garczarek, Laurence; Speich, Sabrina; Audic, Stéphane; Bittner, Lucie; Blanke, Bruno; Brum, Jennifer R; Brunet, Christophe; Casotti, Raffaella; Chase, Alison; Dolan, John R; d'Ortenzio, Fabrizio; Gattuso, Jean-Pierre; Grima, Nicolas; Guidi, Lionel; Hill, Christopher N; Jahn, Oliver; Jamet, Jean-Louis; Le Goff, Hervé; Lepoivre, Cyrille; Malviya, Shruti; Pelletier, Eric; Romagnan, Jean-Baptiste; Roux, Simon; Santini, Sébastien; Scalco, Eleonora; Schwenck, Sarah M; Tanaka, Atsuko; Testor, Pierre; Vannier, Thomas; Vincent, Flora; Zingone, Adriana; Dimier, Céline; Picheral, Marc; Searson, Sarah; Kandels-Lewis, Stefanie; Acinas, Silvia G; Bork, Peer; Boss, Emmanuel; de Vargas, Colomban; Gorsky, Gabriel; Ogata, Hiroyuki; Pesant, Stéphane; Sullivan, Matthew B; Sunagawa, Shinichi; Wincker, Patrick; Karsenti, Eric; Bowler, Chris; Not, Fabrice; Hingamp, Pascal; Iudicone, Daniele

    2015-05-22

    Agulhas rings provide the principal route for ocean waters to circulate from the Indo-Pacific to the Atlantic basin. Their influence on global ocean circulation is well known, but their role in plankton transport is largely unexplored. We show that, although the coarse taxonomic structure of plankton communities is continuous across the Agulhas choke point, South Atlantic plankton diversity is altered compared with Indian Ocean source populations. Modeling and in situ sampling of a young Agulhas ring indicate that strong vertical mixing drives complex nitrogen cycling, shaping community metabolism and biogeochemical signatures as the ring and associated plankton transit westward. The peculiar local environment inside Agulhas rings may provide a selective mechanism contributing to the limited dispersal of Indian Ocean plankton populations into the Atlantic.

  5. Dynamics and characteristics of electric-field structures in the auroral return current region observed by Cluster

    NASA Astrophysics Data System (ADS)

    Marklund, G. T.; Karlsson, T.; Figueiredo, S.; Johansson, T.; Lindqvist, P.-A.; André, M.; Buchert, S.; Kistler, L. M.

    2006-02-01

    The temporal evolution and other characteristics of intense quasi-static electric fields in the return current region are discussed using Cluster observations. A narrow-scale, divergent electric field, the high-altitude signature of a positive U-shaped potential structure, was observed at the poleward edge of the central plasma sheet, close to magnetic midnight at a geocentric distance of about 4.2 Earth radii. Its acceleration potential increased from less than 1 to 3 kV on a 100 s timescale, similar to the formation time for ionospheric plasma density holes, and consistent with previous results for this kind of structure. In the adjacent upward current region, an energy decrease in inverted-V ions was observed some minutes prior to this. The inverted-V potential decrease was roughly equal to the subsequent perpendicular potential increase in the return current region, suggesting that a potential redistribution took place between the two adjacent current branches. Other characteristics of this and three other return current structures are summarized, to illustrate both common and different features of these. The structures are characterized by (all values have been mapped to the ionospheric level) peak electric-field magnitudes of ap1 V m-1, bipolar or unipolar profiles, occurrence at plasma boundaries associated with plasma density gradients, perpendicular scale sizes of ap10 km, downward field-aligned currents of ap10 μA m-2, and upward electron beams with characteristic energies of a few hundred to a few thousand eV. The bipolar and unipolar electric-field profiles are proposed to reflect whether plasma populations, dense enough to support upward field-aligned currents (by which the return current can close) exist on both sides, or on one side only of the boundary.

  6. THE n-DISTRIBUTION OF ELECTRONS AND DOUBLE LAYERS IN THE ELECTRON-BEAM-RETURN-CURRENT SYSTEM OF SOLAR FLARES

    SciTech Connect

    Karlicky, Marian

    2012-05-01

    We investigate processes in the electron-beam-return-current system in the impulsive phase of solar flares to answer a question about the formation of the n-electron distribution detected in this phase of solar flares. An evolution of the electron-beam-return-current system with an initial local density depression is studied using a three-dimensional electromagnetic particle-in-cell model. In the system the strong double layer is formed. Its electric field potential increases with the electron beam flux. In this electric field potential, the electrons of background plasma are strongly accelerated and propagate in the return-current direction. The high-energy part of their distribution at the high-potential side of the strong double layer resembles that of the n-distribution. Thus, the detection of the n-distributions, where a form of the high-energy part of the distribution is the most important, can indicate the presence of strong double layers in solar flares. The similarity between processes in solar flare loops and those in the downward current region of the terrestrial aurora, where the double layers were observed by FAST satellite, supports this idea.

  7. Agulhas leakage dynamics affects decadal variability in Atlantic overturning circulation.

    PubMed

    Biastoch, A; Böning, C W; Lutjeharms, J R E

    2008-11-27

    Predicting the evolution of climate over decadal timescales requires a quantitative understanding of the dynamics that govern the meridional overturning circulation (MOC). Comprehensive ocean measurement programmes aiming to monitor MOC variations have been established in the subtropical North Atlantic (RAPID, at latitude 26.5 degrees N, and MOVE, at latitude 16 degrees N) and show strong variability on intraseasonal to interannual timescales. Observational evidence of longer-term changes in MOC transport remains scarce, owing to infrequent sampling of transoceanic sections over past decades. Inferences based on long-term sea surface temperature records, however, supported by model simulations, suggest a variability with an amplitude of +/-1.5-3 Sv (1 Sv = 10(6) m(3) s(-1)) on decadal timescales in the subtropics. Such variability has been attributed to variations of deep water formation in the sub-arctic Atlantic, particularly the renewal rate of Labrador Sea Water. Here we present results from a model simulation that suggest an additional influence on decadal MOC variability having a Southern Hemisphere origin: dynamic signals originating in the Agulhas leakage region at the southern tip of Africa. These contribute a MOC signal in the tropical and subtropical North Atlantic that is of the same order of magnitude as the northern source. A complete rationalization of observed MOC changes therefore also requires consideration of signals arriving from the south.

  8. Review of X-43A Return to Flight Activities and Current Status

    NASA Technical Reports Server (NTRS)

    Reubush, David E.; Nguyen, Luat T.; Rausch, Vincent L.

    2004-01-01

    This paper provides an overview and status of the return to flight activities for the X-43A scramjet flight demonstrator after the first flight mishap. The first flight was attempted on June 2, 2001 and resulted in vehicle destruction by range safety when the booster went out of control early in the flight. In the time since the mishap much work has been done to examine the causes of the failure and make modifications to the booster to insure that the boost for the second flight will be successful. In addition, all other aspects of the flight have been examined to maximize the probability of a successful flight.

  9. Agulhas leakage as a key process in the modes of Quaternary climate changes.

    PubMed

    Caley, Thibaut; Giraudeau, Jacques; Malaizé, Bruno; Rossignol, Linda; Pierre, Catherine

    2012-05-01

    Heat and salt transfer from the Indian Ocean to the Atlantic Ocean (Agulhas leakage) has an important effect on the global thermohaline circulation and climate. The lack of long transfer record prevents elucidation of its role on climate changes throughout the Quaternary. Here, we present a 1,350-ka accumulation rate record of the planktic foraminiferal species Globorotalia menardii. We demonstrate that, according to previous assumptions, the presence and reseeding of this fauna in the subtropical southeast Atlantic was driven by interocean exchange south of Africa. The Agulhas transfer strengthened at glacial ice-volume maxima for every glacial-interglacial transition, with maximum reinforcements organized according to a 400-ka periodicity. The long-term dynamics of Agulhas leakage may have played a crucial role in regulating meridional overturning circulation and global climate changes during the Mid-Brunhes event and the Mid-Pleistocene transition, and could also play an important role in the near future.

  10. Agulhas leakage as a key process in the modes of Quaternary climate changes

    PubMed Central

    Caley, Thibaut; Giraudeau, Jacques; Malaizé, Bruno; Rossignol, Linda; Pierre, Catherine

    2012-01-01

    Heat and salt transfer from the Indian Ocean to the Atlantic Ocean (Agulhas leakage) has an important effect on the global thermohaline circulation and climate. The lack of long transfer record prevents elucidation of its role on climate changes throughout the Quaternary. Here, we present a 1,350-ka accumulation rate record of the planktic foraminiferal species Globorotalia menardii. We demonstrate that, according to previous assumptions, the presence and reseeding of this fauna in the subtropical southeast Atlantic was driven by interocean exchange south of Africa. The Agulhas transfer strengthened at glacial ice-volume maxima for every glacial-interglacial transition, with maximum reinforcements organized according to a 400-ka periodicity. The long-term dynamics of Agulhas leakage may have played a crucial role in regulating meridional overturning circulation and global climate changes during the Mid-Brunhes event and the Mid-Pleistocene transition, and could also play an important role in the near future. PMID:22508999

  11. Cutaneous Leishmaniasis: Current Treatment Practices in the USA for Returning Travelers

    PubMed Central

    Eiras, Daniel P.; Kirkman, Laura A.; Murray, Henry W.

    2015-01-01

    Opinion statement Leishmaniasis, a protozoal infection transmitted by sandfly bite, produces a clinical spectrum of disease ranging from asymptomatic infection to ulcerative skin and mucosal lesions to visceral involvement. Leishmaniasis is endemic in regions of Africa, the Middle East, south Asia, southern Europe, northern South America, and Central America. There has been an increase in imported leishmaniasis into developed, non-endemic countries due to increasing global travel. While pentavalent antimonials have been the mainstay of antileishmanial treatment for decades, newer therapeutic options have become available for all forms of infection, including liposomal amphotericin B, miltefosine, fluconazole, and ketoconazole. For the returning traveler with cutaneous leishmaniasis in the USA, treatment approaches are determined based on infecting species, initial presentation, extent and progression of disease, the advantages and drawbacks of available parenteral and oral drugs, and clinician-consultant experience. PMID:25788870

  12. Ocean Virtual Laboratory: A New Way to Explore Multi-Sensor Synergy Demonstrated over the Agulhas Region

    NASA Astrophysics Data System (ADS)

    Collard, F.; Quartly, G. D.; Konik, M.; Johannessen, J. A.; Korosov, A.; Chapron, B.; Piolle, J.-F.; Herledan, S.; Darecki, M.; Isar, A.; Nafornita, C.

    2015-12-01

    Ocean Virtual Laboratory is an ESA-funded project to prototype the concept of a single point of access for all satellite remote-sensing data with ancillary model output and in situ measurements for a given region. The idea is to provide easy access for the non-specialist to both data and state-of-the-art processing techniques and enable their easy analysis and display. The project, led by OceanDataLab, is being trialled in the region of the Agulhas Current, as it contains signals of strong contrast (due to very energetic upper ocean dynamics) and special SAR data acquisitions have been recorded there. The project also encourages the take up of Earth Observation data by developing training material to help those not in large scientific or governmental organizations make the best use of what data are available. The website for access is: http://ovlproject.oceandatalab.com/

  13. DE 1 observation of return current regions in the nightside auroral oval

    SciTech Connect

    Marshall, J.A.; Burch, J.L.; Kan, J.R.; Slavin, J.A.

    1988-12-01

    Data from the Dynamics Explorer 1 high altitude plasma instrument (HAPI) and magnetometer (MAG-A) are used to examine particle acceleration and Birkeland current phenomena in the mid-altitude (10,000--20,000 km) nightside auroral region between 2000 and 2200 hours MLT. Field-aligned current densities as derived from the two instruments are compared, generally resulting in good agreement. The latitudinal distribution of upward and downward field-aligned currents is examined, both on a large scale with respect to regional boundaries and on a local scale with respect to individual inverted-V events. The charge carriers of the downward currents are found to be cold ionospheric electrons accelerated into upward beams by potential drops of a few tens of volts located at altitudes near 1 Earth radius. In several instances, large potential differences below the satellite are indicated by energetic upward ion beams with no (or very small) potential drops above the satellite. In these cases, very small Birkeland currents (approx. <10/sup -8/ A/m/sup 2/) are observed above the inverted V, suggesting the possibility that the field-aligned current systems associated with individual inverted-V events may close at relatively low altitudes above the auroral oval, or that field-aligned potential differences may be generated without significant Birkeland currents. copyright American Geophysical Union 1988

  14. The Role of Education in Economic Growth: Theory, History and Current Returns

    ERIC Educational Resources Information Center

    Breton, Theodore R.

    2013-01-01

    Background: This paper was prepared to address the issue of whether current levels of public expenditures on education are cost-effective in countries with widely differing average levels of education. Purpose: The paper examines the role of education in economic growth from a theoretical and historic perspective, addresses why education has been…

  15. Alumni of High School Internship Program Return for 25th Anniversary to Inspire Current Students | Poster

    Cancer.gov

    The Building 549 auditorium is often packed with high school interns eager to hear a scientific lecture. On April 22, however, the room swelled with interns spanning a wider age range. At the 25th Werner H. Kirsten Student Intern Program (WHK SIP) Anniversary Symposium, incoming, current, and former interns gathered to celebrate the program, which has provided biomedical research experience for local high school seniors.

  16. Two-stream stability properties of the return-current layer for intense ion beam propagation through background plasma

    SciTech Connect

    Startsev, Edward A.; Davidson, Ronald C.; Dorf, Mikhail

    2009-09-15

    When an ion beam with sharp edge propagates through a background plasma, its current is neutralized by the plasma return current everywhere except at the beam edge over a characteristic transverse distance {delta}x{sub perpendicular}{approx}{delta}{sub pe}, where {delta}{sub pe}=c/{omega}{sub pe} is the collisionless skin depth and {omega}{sub pe} is the electron plasma frequency. Because the background plasma electrons neutralizing the ion beam current inside the beam are streaming relative to the background plasma electrons outside the beam, the background plasma can support a two-stream surface-mode excitation. Such surface modes have been studied previously assuming complete charge and current neutralization, and have been shown to be strongly unstable. In this paper we study the detailed stability properties of this two-stream surface mode for an electron flow velocity profile self-consistently driven by the ion beam. In particular, it is shown that the self-magnetic field generated inside the unneutralized current layer, which has not been taken into account previously, completely eliminates the instability.

  17. Agulhas Ridge, South Atlantic: the peculiar structure of a transform fault

    NASA Astrophysics Data System (ADS)

    Uenzelmann-Neben, G.; Gohl, K.

    2003-04-01

    Transform faults constitute conservative plate boundaries, where adjacent plates are in tangential contact. Transform faults in the ocean are marked by fracture zones, which are long, linear, bathymetric depressions. One of the largest transform offsets on Earth can be found in the South Atlantic. The 1200 km long Agulhas Falkland Fracture Zone (AFFZ), form by this, developed during the Early Cretaceous break-up of West Gondwana. Between approx. 41°S, 16°E and 43°S, 9°E the Agulhas Falkland Fracture Zone is characterised by a pronounced topographic anomaly, the Agulhas Ridge. The Agulhas Ridge rises more than 2 km above the surrounding seafloor. The only equivalent to this kind of topographic high, as part of the AFFZ, is found in form of marginal ridges along the continental parts of the fracture zone, namely the Falkland Escarpment at the South American continent and the Diaz Ridge adjacent to South Africa. But the Agulhas Ridge differs from both the Falkland Escarpment and the Diaz Ridge in the facts (1) that it was not formed during the early rift-drift phase, and (2) that it separates oceanic crust of different age and not continental from oceanic crust. A set of high-resolution seismic reflection data (total length 2000 km) and a seismic refraction line across the Agulhas Ridge give new information on the crustal and basement structure of this tectonic feature. We have observed that within the Cape Basin, to the North, the basement and sedimentary layers are in parts strongly deformed. We observe basement highs, which point towards intrusions. Both the basement and the sedimentary sequence show strong faulting. This points towards a combined tectono-magmatic activity, which led to the formation of basement ridges parallel to the Agulhas Ridge. Since at least the pre-Oligocene parts and, locally, the whole sedimentary column are affected we infer that the renewed activity began in the Middle Oligocene and may have lasted into the Quaternary. As an origin

  18. Observation of mesoscale ocean currents from GEOSAT altimeter data

    NASA Astrophysics Data System (ADS)

    Naeije, M. C.; Wakker, K. F.; Scharroo, R.; Ambrosius, B. A. C.

    This paper discusses an altimeter data processing technique designed to compute time series of the mesoscale dynamic sea surface and to produce mean sea surfaces and surface variability. The technique has been applied to GEOSAT data collected over the North and South Atlantic and the South Indian Ocean. The computed mean sea surfaces show a high correlation with ocean bottom topography, whereas the variability is found to be associated with mesoscale ocean currents. High variability levels are spotted near the Gulfstream Extension and the Agulhas Return Current. Detailed examination of the sea surface and related flow field time series made it possible to identify a large number of eddies and to keep track of them in both the nort-west and south-east Atlantic. Additionally, some of the eddy characteristics have been resolved such as translation and swirl velocity. It is found that the eddy motion is affected by ocean bottom slopes.

  19. Multicentennial Agulhas leakage variability and links to North Atlantic climate during the past 80,000 years

    NASA Astrophysics Data System (ADS)

    Dyez, Kelsey A.; Zahn, Rainer; Hall, Ian R.

    2014-12-01

    New high-resolution sea surface temperature (SST) and sea surface salinity (SSS) estimates are presented from the Agulhas Bank slope in the Atlantic sector of the Agulhas Corridor using planktic foraminiferal (Globigerinoides ruber) δ18O and Mg/Ca-derived SST. By focusing on the last 80,000 years, this is the first fine-scale Agulhas leakage record that overlaps in time with much of the Greenland ice core record of abrupt climate changes in the North Atlantic region. The multicentennial profiles indicate instances of warm SST and/or increased SSS coincident with Northern Hemisphere cool periods, followed by Northern Hemisphere warming. These periods of enhanced SST and SSS in the Agulhas Corridor occur at the last glacial termination (T1) and during North Atlantic cold episodes associated with Heinrich (H) meltwater events. To a first-order approximation, the timing of maximal salinity events in relation to periods of North Atlantic freshwater perturbation is consistent with the concept suggested by climate models that enhanced Agulhas leakage provides for buoyancy compensation and can potentially trigger increased convective activity in the North Atlantic, thereby restoring Atlantic overturning circulation after relatively weak states.

  20. Observations of the vertical and temporal evolution of a Natal Pulse along the Eastern Agulhas Bank

    NASA Astrophysics Data System (ADS)

    Pivan, Xavier; Krug, Marjolaine; Herbette, Steven

    2016-09-01

    This study reinvestigates the work of Lutjeharms et al. (2001, 2003) who documented the properties of a Natal Pulse using isopycnal Lagrangian floats. We combined Lagrangian analyses and Eulerian maps derived from objective analysis to better describe the evolution of a Natal Pulse along three density surfaces referred to as the surface (satellite-observed), shallow (isopycnal 1026.8 kg m-3), and deep (isopycnal 1027.2 kg m-3) layer. Our observations show that this Natal Pulse extended to a depth of 1000 m and was associated with cyclonic relative vorticity values of about 6.5-8.5 × 10-5 s-1 in the surface and shallow layer and 4 × 10-5 s-1 in the deep layer. This Natal Pulse contributed to cross-shelf exchange through the offshore advection of Eastern Agulhas Bank water near the surface, onshore advection of South Indian Central Water and/or Indian Equatorial Water in the shallow layer, and Antarctic Intermediate Water in the deep layer. Sea surface temperature maps showed that the downstream progression of the Natal Pulse along the 3000 m isobath was related to a readjustment of its rotation axis. This readjustment advected Eastern Agulhas Bank water into the Natal Pulse eddy and triggered a SST cooling of about 3°C in the cyclonic area. The importance of a warm recirculating Agulhas plume originating from the Natal Pulse was highlighted. This warm water plume extended to a depth of 700 m and was associated with onshore velocities exceeding those experienced within the Natal Pulse eddy by a factor of 2. Our observations indicate that the June/July 1998 Natal Pulse and its associated plumes enhanced cross-shelf exchanges.

  1. Lagrangian Validation of Numerical Drifter Trajectories Using Drifting Buoys: Application to the Agulhas System

    DTIC Science & Technology

    2009-05-20

    are from Lagrangian float exper- iments inside three different models: NCOM, ORCA , and AG01. The models vary in their ability to simulate the...num- ber of floats that is released at 30°S is 1.5 x 106. The 1/2° global ocean sea-ice ORCA model (Biastoch et al., 2008c) is based on NEMO (Madec...inside the ORCA model, that spans the greater Agulhas region (20°W-70°E; 47°S- 7°S) (Biastoch et al., 2008a,b). The two-way nesting procedure

  2. The South Indian Ocean Countercurrent: a return pathway of the Indonesian Throughflow?

    NASA Astrophysics Data System (ADS)

    Lambert, Erwin; leBars, Dewi; de Ruijter, Will

    2014-05-01

    The South Indian Ocean Counter Current (SICC) is associated with a thermal front embedded in a broad eastward flow across the subtropical Indian Ocean and feeds into the poleward Leeuwin Current (LC). Previous studies have shown that the LC and SICC are sensitive to variations of the inflow of Pacific water through the Indonesian Passages (ITF). These subtropical countercurrents, of which the SICC is an example, are characterized by high eddy activity and theoretical work has shown the non-linear nature of their dynamics. That has motivated us to investigate the inertial response to the ITF of the IO circulaion. Analysis of two global eddy resolving model runs with the Indonesian Passages open and closed showed that the full 15 Sv of the ITF flows through the Mozambique Channel but only 10 Sv ends up in the Agulhas Current. This suggests that the SICC-LC system forms part of the return pathway of the ITF to the Pacific. Using the Hallberg Isopycnal Model we have investigated the combined effect of ITF, wind- and buoyancy forcing on the Indian Ocean circulation in the inertial boundary layer regime.

  3. Two-dimensional current density and temperature development in the return rail of an EM launcher with temperature-dependent properties

    SciTech Connect

    Drake, P.A.; Rathmann, C.E. )

    1991-01-01

    This paper describes a method successfully used to model the two-dimensional current and temperature development in the return rail of an EML during launch, incorporating temperature-dependent electrical and thermal material properties. Due to these temperature dependencies and the non-linearities they introduce, the derived equations must be solved numerically. Comparisons of the current and temperature responses are made with the results of a previously published constant-property model. This two- dimensional model duplicates the breech responses of one- dimensional analyses and, in addition, provides the detailed structure of the current and temperature sheaths. In particular, application of this model shows that the most severe gradients occur away from the breech, and that they are much in excess of those predicted by one-dimensional analyses.

  4. Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse

    PubMed Central

    2016-01-01

    Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS) was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA). However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a) automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b) the use of just a single CSA value in a pulsatile vessel is inaccurate; (c) time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave) and with the outflow (jugular venous pulse) in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders. PMID:27006525

  5. A description of eddy-mean flow feedbacks in equatorial and boundary current systems of the South Indian Ocean

    NASA Astrophysics Data System (ADS)

    Aguiar-González, Borja; Ponsoni, Leandro; Maas, Leo R. M.; Ridderinkhof, Herman; van Aken, Hendrik

    2015-04-01

    While many observational and modeling efforts have addressed eddy-mean flow interactions acting over nearly idealized zonal jets, little is know about whether findings in those studies can be extended to current systems with different configurations in the real ocean. This topic is of special interest for ocean-climate models where eddy interactions with the mean flow may be unresolved, demanding further insight on the mechanism by which the eddy field and the mean circulation should feed back in a realistic representation of future climate change scenarios. Following this motivation, we investigate local exchange of momentum and kinetic energy operating in a variety of eddy-mean flow systems of the South Indian Ocean (SIO). To this aim we use 21 years (1993-2013) of newly processed satellite altimetry observations, and adopt a definition of the mean flow as a seasonally-dependent temporal mean where the eddy field encompasses the daily instantaneous deviation from the altimeter-derived velocities. This approach allows time-varying feedbacks to evolve throughout the year. We find that the eddy field feeds back on the mean circulation, contributing importantly to the overall seasonal strengthening and weakening of all current systems involved in the tropical and subtropical gyre of the SIO. Although significant contributions to the momentum and energy balances were also obtained along the Agulhas (Return) Current and the Antarctic Circumpolar Current (ACC), they exhibit a weak/absent seasonal cycle, suggesting that the strength of these dynamical processes is mostly persistent throughout the year. Spatial distribution of the eddy kinetic energy conversion rates and the convergence of horizontal eddy momentum fluxes indicate that over regions where the eddy field draws energy from the mean flow through barotropic instabilities, the current is importantly decelerated by alongstream eddy forces on its upstream side, while further downstream the situation reverses with

  6. Ocean circulation in the southern Benguela region from the Pliocene to the Pleistocene: tracking Agulhas leakage into the SE Atlantic

    NASA Astrophysics Data System (ADS)

    Petrick, Benjamin; McClymont, Erin; Felder, Sojna; Leng, Melanie

    2013-04-01

    The transition from the warmth of the middle Pliocene to the large amplitude, 100 kyr glacial-interglacial cycles of the late Pleistocene provides a way to understand the forcings and impacts of regional and global climate change. Here, we investigate changes in ocean circulation over the period from 3.5 Ma to present using a marine sediment core, ODP Site 1087 (31o28'S, 15o19'E, 1374m water depth). ODP 1087 is located in the South-east Atlantic Ocean, outside the Benguela upwelling region. Its location allows investigation of the history of the heat and salt transfer to the Atlantic Ocean from the Indian Ocean ("Agulhas leakage"), which plays an important part in the global thermohaline circulation. It is not known how this transfer reacted to generally warmer global temperatures during the mid-Pliocene, nor to the transition to a globally cooler climate in the early Pleistocene. Our approach is to apply several organic geochemistry proxies and foraminiferal analyses to reconstruct the history of ODP 1087. These include the U37K' index to reconstruct sea surface temperatures, pigment analysis for understanding productivity changes, and foraminifera assemblage analysis to detect the presence of different water masses at the site. We have identified changes in SSTs and biological productivity that we argue to reflect shifts in the position of the Benguela upwelling cells, and a changing influence of Agulhas leakage. Our new data reveal a different organization in the Southeast Atlantic. It shows that during the Pliocene ODP 1087 was dominated by Benguela upwelling which had shifted south. We find no evidence for Agulhas leakage during the mid Pliocene, which could mean that Agulhas Leakage was severely reduced during the mid Pliocene. The implications of these results for understanding Plio-Pleistocene climate changes will be explored here.

  7. Pleistocene ice-rafted debris events recorded at the Agulhas Plateau - indicators of intermittent Indian-Atlantic gateway closure

    NASA Astrophysics Data System (ADS)

    Ziegler, M.; Hall, I. R.; Siret, P. J.; Zahn, R.

    2012-04-01

    Interocean exchange of heat and salt around South Africa - the so called 'Agulhas Leakage' - is thought to be a key link in the maintenance of the Atlantic meridional overturning circulation (AMOC). It takes place at the Agulhas Retroflection, largely by the intermittent shedding of enormous rings that penetrate into the South Atlantic Ocean (Lutjeharms, 1996, Biastoch et al., 2008; Beal et al., 2011). Recent palaeoceanographic studies suggest that variability in the latitudinal position of the subtropical front (STF) in the Southern Ocean, act as a gatekeeper for the Agulhas retroflection and moreover, that a variable northward migration of the STF potentially modulated the severity of glacial periods by altering the amount of Agulhas leakage with consequences for the AMOC (Bard and Rickaby, 2009). Here we present a high-resolution record of ice rafted debris (IRD) from the southern Agulhas Plateau (sediment core MD02-2588, 41°19,90 S and 25°49,70 E, 2907 m water depth) covering the last 350,000 years. We find distinct millennial scale events with high abundances of IRD in the sediments. Scanning-electron microscope analysis of individual grains shows a wide range of morphologies, with a high degree of angularity being a dominant feature, with surface microfeatures (linear fractures, grooves and troughs) that are typical for glacial origin and transport. We interpret these IRD events as indicators for a northward shift of the Southern Ocean frontal system, thereby allowing sufficient cooling and iceberg survivability as far north as the Agulhas Plateau. Our proxy record suggests significant millennial scale variability of the frontal movements throughout the last three glacial cycles. Largest IRD peaks occur during marine isotope stage 8 (~300 ka BP) and hence during a period for which an extreme northward shift in the STF has been identified previously (Bard and Rickaby, 2009). We compare our IRD record with records of millennial scale climate variability in

  8. Lightning return stroke models

    NASA Technical Reports Server (NTRS)

    Lin, Y. T.; Uman, M. A.; Standler, R. B.

    1980-01-01

    We test the two most commonly used lightning return stroke models, Bruce-Golde and transmission line, against subsequent stroke electric and magnetic field wave forms measured simultaneously at near and distant stations and show that these models are inadequate to describe the experimental data. We then propose a new return stroke model that is physically plausible and that yields good approximations to the measured two-station fields. Using the new model, we derive return stroke charge and current statistics for about 100 subsequent strokes.

  9. Changing surface water conditions for the last 500 ka in the Southeast Atlantic: Implications for variable influences of Agulhas leakage and Benguela upwelling

    NASA Astrophysics Data System (ADS)

    Petrick, Benjamin F.; McClymont, Erin L.; Marret, Fabienne; Meer, Marcel T. J.

    2015-09-01

    The Southeast Atlantic Ocean is an important component of global ocean circulation, as it includes heat and salt transfer into the Atlantic through the Agulhas leakage as well as the highly productive Benguela upwelling system. Here we reconstruct sea surface temperatures (SSTs) from Ocean Drilling Program (ODP) Site 1087 in the Southeast Atlantic to investigate surface ocean circulation patterns during the late Pleistocene (0-500 ka). The UK'37 index and dinoflagellate cyst assemblages are used to reconstruct SSTs, δDalkenone is used to reconstruct changes in sea surface salinity, and mass accumulation rates of alkenones and chlorine pigments are quantified to detect changing marine export productivity. The greatest amplitude of SST warming precedes decreases in benthic δ18O and therefore occurs early in the transition from glacials to interglacials. The δDalkenone, as a salinity indicator, increases before SSTs, suggesting that the pattern of Agulhas leakage is more complex than suggested by SST proxies. Marine isotope stage (MIS) 10 shows an anomalous pattern: it is marked by a pronounced increase in chlorine concentration, which may be related to enhanced/expanded Benguela upwelling reaching the core site. We find no evidence of an absence of Agulhas leakage throughout the record, suggesting that there is no Agulhas cutoff even during MIS 10. Finally, the ODP Site 1087 record shows an increasing strength of Agulhas leakage towards the present day, which may have impacted the intensity of the Atlantic meridional overturning circulation. As a result, the new analyses from ODP Site 1087 demonstrate a complex interaction between influences of the Benguela upwelling and the Agulhas leakage through the late Pleistocene, which are inferred here to reflect changing circulation patterns in the Southern Ocean and in the atmosphere.

  10. Tatanka Returns.

    ERIC Educational Resources Information Center

    Simonelli, Richard

    1993-01-01

    Describes efforts of the InterTribal Bison Cooperative (Rapid City, SD) to reintroduce the buffalo for cultural purposes to American Indian reservations. Explains how the buffalo's return is contributing to community wellness. Discusses career opportunities for both Native and non-Native people in buffalo management. (LP)

  11. Declining Returns.

    ERIC Educational Resources Information Center

    Rosen, Gerald H.; Perrin, Robert

    1992-01-01

    The Teachers Insurance and Annuities Association's (TIAA) College Retirement and Equity Fund is criticized for its low returns and its chief executive officer's recent salary raise. It is said to be in need of additional regulation and policyholder involvement. A TIAA vice president responds that the analysis given is inaccurate and misleading.…

  12. Accelerated electron distributions with high- and low-energy cutoffs deduced from the application of a return-current model to solar flare X-ray spectra observed by RHESSI

    NASA Astrophysics Data System (ADS)

    Alaoui, Meriem; Holman, Gordon D.

    2015-04-01

    The X-ray bremsstrahlung emission observed from solar flares requires a high flux, and corresponding high current, of non-thermal electrons. This current is thought to be stabilized by a co-spatial return current, which also resupplies electrons to the acceleration region. In the standard collisional thick-target model (CTTM), electrons accelerated in the corona lose all of their energy through Coulomb collisions when they reach the higher densities in the lower atmosphere of the sun. In the presence of the return current, however, the electrons also lose energy in the corona as they propagate downward. These losses introduce a break into the observed X-ray spectrum if the potential drop associated with the return current is sufficiently high.We analyzed the temporal evolution of RHESSI (Ramaty High Energy Solar Spectroscopic Imager) spectra from a solar flare with strong spectral breaks in terms of a return-current collisional thick-target model (RCCTTM). The presence of strong breaks ensures that albedo and non-uniform ionization are not sufficient to explain the spectral flattening at energies below the break. We find that the model successfully fits the spectral data. The fits were significantly improved with the inclusion of a high-energy cutoff to the injected electron distribution (better chi-squared values and residuals), providing the time evolution of the highest energy to which electrons were accelerated. A lower limit to the low-energy cutoff to the electron distribution was obtained by restricting the beam density to a value less than the ambient coronal density. The derived plasma resistivity and the drift speed of the return-current electrons both suggest that plasma turbulence might have been important in the corona.This work was supported by the NASA Heliophysics Guest Investigator Program and the RHESSI Project.

  13. Changing surface water conditions for the last 500 ka in the Southeast Atlantic:Tracking Agulhas leakage using UK37' and δD

    NASA Astrophysics Data System (ADS)

    Petrick, Benjamin; McClymont, Erin; van der Meer, Marcel; Marret, Fabienne

    2015-04-01

    The Southeast Atlantic Ocean is an important component of global ocean circulation, as it includes heat and salt transfer into the Atlantic through Agulhas Leakage. Here, we reconstruct sea surface temperatures (SSTs) and sea surface salinity from Ocean Drilling Program (ODP) Site 1087 in the Southeast Atlantic to investigate surface ocean circulation patterns during the late Pleistocene (0-500 ka). The alkenone-derived U37K'index and assemblages of dinoflagellate cysts are used to reconstruct SSTs. The hydrogen isotope composition of the alkenones (δDalkenone) is used to reconstruct changes in sea-surface salinity. The greatest amplitude of SST warming precedes decreases in benthic δ18O and therefore occurs early in the transition from glacials to interglacials. The timing of the early warming is consistent with previously published foraminifera reconstructions from the same site (Caley et al., 2012). However, δDalkenone decreases at the start of interglacials, suggesting that sea surface salinity increased earlier than the deglacial warmings, and indicating that the pattern of Agulhas leakage is more complex than suggested by SST proxies alone. Furthermore, the δDalkenonevalues indicate a strong salinity increases occurred before both MIS 11 and MIS 1, which are both periods where there is evidence of connection between increased Agulhas Leakage and a stronger Atlantic meridional overturning circulation (AMOC). Finally, the ODP site 1087 record shows an overall trend of increasing SSTs and δDalkenone towards the present day, suggesting that Agulhas leakage has strengthened since 500 ka, which may have impacted the intensity of the AMOC. Caley, T., Giraudeau, J., Malaize, B., Rossignol, L., Pierre, C., 2012. Agulhas leakage as a key process in the modes of Quaternary climate changes. Proc. Natl. Acad. Sci. 109, 6835-6839. doi:10.1073/pnas.1115545109

  14. Exploiting multi-proxy analysis of marine sediments in the southeast Atlantic: Intensification of Agulhas leakage tied to the start of the 100ka cycles.

    NASA Astrophysics Data System (ADS)

    Petrick, Benjamin; McClymont, Erin; Marret, Fabienne

    2013-04-01

    The transition in orbital forcing from a 41 ka world to a 100 ka world was a major change in the climate regime over the last 1.5 Ma but its causes and its impacts are still being investigated. Here, we present reconstructions of sea-surface temperature (SST), salinity, and plankton assemblages obtained from a single core, ODP site 1087 (31°28'S, 15°19'E, 1374m water depth) spanning the last 1.5 Ma. Our hypothesis is that the response and position of the Agulhas leakage, which transfers heat and salt to the SE Atlantic region, has shifted as a result of changes in the dominant periodicity of orbital forcing. We draw on evidence from the alkenone (U37K') proxy for SST, dinoflagllate species analysis, and foraminifera oxygen isotopes for salinity and ice volume, to identify changes in the input of the Agulhas leakage to the SE Atlantic. We present the first continuous record of SE Atlantic SSTs reaching to 1.5 Ma which spans both the 41 kyr and 100 kyr glacial cycles. We identify large changes in SST and salinity on glacial-interglacial timescales, but show that there is a consistent pattern of SSTs leading salinity and then global ice volume change, so that deglaciation occurs some 5-10 kyr after the onset of rapid warming in the SE Atlantic during the recent glacials and interglacials. This early warming pattern, which characterizes the most recent cycles, began to develop as early at 900 ka, as the 100 kyr cycles became dominant. Before this time there is little evidence of Agulhas leakage in the ODP1087 record. We also show that over the last 600 ka there has been a strengthening of the Agulhas Leakage which has led to warmer interglacials over this time period. Overall the record shows that the strength and location of the Agulhas leakage is sensitive to changes in the dominant cycles in the climate.

  15. Effects of midlatitude westerlies on the paleoproductivity at the Agulhas Bank slope during the penultimate glacial cycle: Evidence from coccolith Sr/Ca ratios

    NASA Astrophysics Data System (ADS)

    Mejia, Luz Maria; Ziveri, Patrizia; Cagnetti, Marilisa; Bolton, Clara; Zahn, Rainer; Marino, Gianluca; Martinez Mendez, Gema; Stoll, Heather

    2015-04-01

    Because modern primary productivity on the Agulhas Bank, off South Africa, is linked to the mid-latitude westerlies, a paleoproductivity record from this area could be used to investigate past may changes in the westerlies dynamics. Coccolith Sr/Ca is a suitable productivity indicator to explore paleoproductivity from the penultimate glacial-interglacial cycle because it is independent of preservation changes that may accompany changes in deepwater circulation. In the Agulhas Bank slope core MD96-2080, the coccolith Sr/Ca record shows that phases of depressed productivity coincided with periods of stratification in the same core, indicated by high relative abundances of the coccolithophore Florisphaera profunda, and with low relative abundances of the upwelling indicator G. bulloides in the Cape Basin. This coherence suggests that upwelling regulated productivity throughout this region. As in the present, we infer that periods of low productivity result from northward positions of the westerlies which block the upwelling-promoting easterlies. Productivity minima also coincide with periods of increased ice-rafted detritus (IRD) deposition on the Agulhas Plateau, which also indicates extreme northward positions of the westerlies. The influence of the westerlies appears to be obliquity-conditioned, as productivity minima occur during low obliquity intervals. The dynamic connection between productivity and the westerlies is supported by coeval salinity changes in the South Indian Gyre that likewise respond sensitively to a poleward contraction of the westerlies.

  16. Influence of tissue conductivity anisotropy on EEG/MEG field and return current computation in a realistic head model: a simulation and visualization study using high-resolution finite element modeling.

    PubMed

    Wolters, C H; Anwander, A; Tricoche, X; Weinstein, D; Koch, M A; MacLeod, R S

    2006-04-15

    To achieve a deeper understanding of the brain, scientists, and clinicians use electroencephalography (EEG) and magnetoencephalography (MEG) inverse methods to reconstruct sources in the cortical sheet of the human brain. The influence of structural and electrical anisotropy in both the skull and the white matter on the EEG and MEG source reconstruction is not well understood. In this paper, we report on a study of the sensitivity to tissue anisotropy of the EEG/MEG forward problem for deep and superficial neocortical sources with differing orientation components in an anatomically accurate model of the human head. The goal of the study was to gain insight into the effect of anisotropy of skull and white matter conductivity through the visualization of field distributions, isopotential surfaces, and return current flow and through statistical error measures. One implicit premise of the study is that factors that affect the accuracy of the forward solution will have at least as strong an influence over solutions to the associated inverse problem. Major findings of the study include (1) anisotropic white matter conductivity causes return currents to flow in directions parallel to the white matter fiber tracts; (2) skull anisotropy has a smearing effect on the forward potential computation; and (3) the deeper a source lies and the more it is surrounded by anisotropic tissue, the larger the influence of this anisotropy on the resulting electric and magnetic fields. Therefore, for the EEG, the presence of tissue anisotropy both for the skull and white matter compartment substantially compromises the forward potential computation and as a consequence, the inverse source reconstruction. In contrast, for the MEG, only the anisotropy of the white matter compartment has a significant effect. Finally, return currents with high amplitudes were found in the highly conducting cerebrospinal fluid compartment, underscoring the need for accurate modeling of this space.

  17. Investigating the role of capacitive coupling between the operating table and the return electrode of an electrosurgery unit in the modification of the current density distribution within the patients’ body

    PubMed Central

    2013-01-01

    Background Electrosurgery units are widely employed in modern surgery. Advances in technology have enhanced the safety of these devices, nevertheless, accidental burns are still regularly reported. This study focuses on possible causes of sacral burns as complication of the use of electrosurgery. Burns are caused by local densifications of the current, but the actual pathway of current within patient’s body is unknown. Numerical electromagnetic analysis can help in understanding the issue. Methods To this aim, an accurate heterogeneous model of human body (including seventy-seven different tissues), electrosurgery electrodes, operating table and mattress was build to resemble a typical surgery condition. The patient lays supine on the mattress with the active electrode placed onto the thorax and the return electrode on his back. Common operating frequencies of electrosurgery units were considered. Finite Difference Time Domain electromagnetic analysis was carried out to compute the spatial distribution of current density within the patient’s body. A differential analysis by changing the electrical properties of the operating table from a conductor to an insulator was also performed. Results Results revealed that distributed capacitive coupling between patient body and the conductive operating table offers an alternative path to the electrosurgery current. The patient’s anatomy, the positioning and the different electromagnetic properties of tissues promote a densification of the current at the head and sacral region. In particular, high values of current density were located behind the sacral bone and beneath the skin. This did not occur in the case of non-conductive operating table. Conclusion Results of the simulation highlight the role played from capacitive couplings between the return electrode and the conductive operating table. The concentration of current density may result in an undesired rise in temperature, originating burns in body region far from

  18. Effects of midlatitude westerlies on the paleoproductivity at the Agulhas Bank slope during the penultimate glacial cycle: Evidence from coccolith Sr/Ca ratios

    NASA Astrophysics Data System (ADS)

    Mejía, Luz María.; Ziveri, Patrizia; Cagnetti, Marilisa; Bolton, Clara; Zahn, Rainer; Marino, Gianluca; Martínez-Méndez, Gema; Stoll, Heather

    2014-07-01

    Modern primary productivity on the Agulhas Bank, off South Africa, has been proposed to be linked to the midlatitude westerlies. A paleoproductivity record from this area may therefore resolve temporal changes in the westerly dynamics. Accordingly, we produced a coccolith Sr/Ca-based paleoproductivity record from core MD96-2080 (Agulhas Bank slope) during the penultimate glacial-interglacial cycle. Deriving the productivity signal from Sr/Ca requires a correction for a temperature effect, here constrained using Mg/Ca sea surface temperatures from the foraminifer Globigerina bulloides from core MD96-2080. Phases of depressed productivity coincided with periods of stratification in the same core, indicated by high relative abundances of the coccolithophore Florisphaera profunda and with low relative abundances of the upwelling indicator G. bulloides in the nearby Cape Basin. These observations collectively suggest that productivity was regulated by upwelling throughout this region. We infer that, as in the present, periods of low productivity result from a more northerly position of the westerlies, potentially accompanied by subtropical front displacements, and blockage of upwelling promoting easterlies. Productivity minima also coincide with periods of increased ice-rafted detritus (IRD) deposition on the Agulhas Plateau, which also indicates extreme northward positions of the westerlies. The influence of the westerlies appears to be obliquity conditioned, as productivity minima (and IRD maxima) occur during low-obliquity intervals. The dynamic connection between productivity and the westerlies is supported by coeval salinity changes in the South Indian Gyre that likewise respond sensitively to a poleward contraction of the westerlies.

  19. Strontium isotope investigation of ungulate movement patterns on the Pleistocene Paleo-Agulhas Plain of the Greater Cape Floristic Region, South Africa

    NASA Astrophysics Data System (ADS)

    Copeland, Sandi R.; Cawthra, Hayley C.; Fisher, Erich C.; Lee-Thorp, Julia A.; Cowling, Richard M.; le Roux, Petrus J.; Hodgkins, Jamie; Marean, Curtis W.

    2016-06-01

    Middle Stone Age sites located within the Greater Cape Floristic Region on the South African southern coast have material culture with early evidence for key modern human behaviors such as projectile weaponry, large animal hunting, and symbolic behavior. In order to interpret how and why these changes evolved, it is necessary to understand their ecological context as it has direct relevance to foraging behavior. During periods of lowered sea level, a largely flat and vast expanse of land existed south of the modern coastline, but it is now submerged by higher sea levels. This exposed area, the Paleo-Agulhas Plain, likely created an ecological context unlike anything in the region today, as evidenced by fossil assemblages dominated by migratory ungulates. One hypothesis is that the Paleo-Agulhas Plain supported a migration ecosystem of large grazers driven by summer rainfall, producing palatable forage during summer in the east, and winter rainfall, producing palatable forage during winter in the west. Alternatively, ungulates may have been moving from the coastal plain in the south to the interior north of the Cape Fold Mountains, as observed for elephants in historic times. In this study, we assess ungulate movement patterns with inter- and intra-tooth enamel samples for strontium isotopes in fossil fauna from Pinnacle Point sites PP13B and PP30. To accomplish our goals we created a bioavailable 87Sr/86Sr isoscape for the region by collecting plants at 171 sampling sites and developing a geospatial model. The strontium isotope results indicate that ungulates spent most of their time on the Paleo-Agulhas Plain and avoided dissected plain, foothill, and mountain habitats located more than about 15 km north of the modern coastline. The results clearly exclude a north-south (coastal-interior) movement or migration pattern, and cannot falsify the east-west movements hypothesized in the south coast migration ecosystem hypothesis.

  20. 'Self-consistent' production of ion conics on return current region auroral field lines - A time-dependent, semi-kinetic model

    NASA Technical Reports Server (NTRS)

    Brown, David G.; Wilson, Gordon R.; Horwitz, James L.; Gallagher, Dennis L.

    1991-01-01

    We describe initial results from a time-dependent, semi-kinetic model of plasma outflow incorporating wave-particle interactions along current-carrying auroral field lines. Electrostatic waves are generated by the current driven ion cyclotron instability (CDICI), causing perpendicular velocity diffusion of ions plus electron heating via anomalous resistivity when and where the relative drift between electrons and ions exceeds certain critical velocities. Using the local bulk parameters we calculate these critical velocities, and so are able to self-consistently switch on and off the heating of the various particle species. Due to the dependence of these critical velocities on the bulk parameters of the species the heating effects exhibit quite complex spatial and temporal variations. A wide range of ion distribution functions are observed in these simulations, including conics with energies of a few electron volts and 'ring' distributions. The rings are seen to be a natural result of transverse heating and velocity filter effects and do not require coherent acceleration processes. We also observe the formation of a density depletion in hydrogen and enhanced oxygen densities at high altitudes.

  1. Sample Return Science

    NASA Astrophysics Data System (ADS)

    Williford, K. H.; Allwood, A.; Beegle, L. W.; Bhartia, R.; Flannery, D.; Hoffmann, A.; Mora, M. F.; Orbay, J.; Petrizzo, D. A.; Tuite, M. L., Jr.; Willis, P. A.

    2014-12-01

    The first clear identification of an ancient habitable environment on Mars by the Mars Science Laboratory (MSL) rover mission relied on a synthetic analytical approach combining orbital and surface imagery and spectroscopy with sophisticated sample acquisition and handling technology including a rotary percussive drill that provided powdered rock for bulk geochemical analysis [1]. The recent announcement of the instrument package for the proposed NASA Mars2020 rover mission, including micro x-ray fluorescence (PIXL) for elemental mapping as well as scanning ultraviolet laser fluorescence and Raman (SHERLOC) suggests a shift in emphasis of Mars surface science towards spatially resolved geochemical analysis that will support the selection and acquisition of samples for coring, caching, and possible return to Earth for further analysis. During a recent field expedition to investigate Archean and Proterozoic biosignatures in the Pilbara region of Western Australia, we deployed a dry, rotary percussive coring drill with a bit assembly analogous to that being considered for Mars2020. Six targets of varying age and lithology were sampled with the coring drill, and surrounding and adjacent rock samples were collected simultaneously. These samples were subsequently prepared and subsampled for bulk and in situ, spatially resolved analysis using conventional laboratory methods as well as the existing PIXL and SHERLOC platforms currently in development. Here we present new approaches and data from this integrated and ongoing program of "sample return science" designed to simulate, and eventually reduce risk associated with a long-term effort towards Mars sample return. [1] Grotzinger, J.P. et al. 2014. Science 343 DOI: 10.1126/science.1242777.

  2. The Returns to Community College

    ERIC Educational Resources Information Center

    Agan, Amanda Yvonne

    2013-01-01

    Almost half of postsecondary students are currently enrolled in community colleges. These institutions imply that even amongst students with the same degree outcome there is considerable heterogeneity in the path taken to get there. I estimate the life-cycle private and social returns to the different postsecondary paths and sequential decisions…

  3. Why Do Staff Return?

    ERIC Educational Resources Information Center

    Magnuson, Connie

    1992-01-01

    Surveyed 211 returning staff from 25 camps and interviewed 19 returning staff to study factors that influence a counselor's decision to return to camp. Examined the following dimensions of motivation and hygiene factors: (1) stimulation or inspiration; (2) personal; (3) job-related experience; (4) living conditions and camp life; (5) camp…

  4. Strontium isotope investigation of ungulate movement patterns on the Pleistocene Paleo-Agulhas Plain of the Greater Cape Floristic Region, South Africa

    SciTech Connect

    Copeland, Sandi R.; Cawthra, Hayley C.; Fisher, Erich C.; Lee-Thorp, Julia A.; Cowling, Richard M.; le Roux, Petrus J.; Hodgkins, Jamie; Marean, Curtis W.

    2016-04-16

    Middle Stone Age sites located within the Greater Cape Floristic Region on the South African southern coast have material culture with early evidence for key modern human behaviors such as projectile weaponry, large animal hunting, and symbolic behavior. In order to interpret how and why these changes evolved, it is necessary to understand their ecological context as it has direct relevance to foraging behavior. During periods of lowered sea level, a largely flat and vast expanse of land existed south of the modern coastline, but it is now submerged by higher sea levels. This exposed area, the Paleo-Agulhas Plain, likely created an ecological context unlike anything in the region today, as evidenced by fossil assemblages dominated by migratory ungulates. One hypothesis is that the Paleo-Agulhas Plain supported a migration ecosystem of large grazers driven by summer rainfall, producing palatable forage during summer in the east, and winter rainfall, producing palatable forage during winter in the west. Furthermore, ungulates may have been moving from the coastal plain in the south to the interior north of the Cape Fold Mountains, as observed for elephants in historic times.

  5. Strontium isotope investigation of ungulate movement patterns on the Pleistocene Paleo-Agulhas Plain of the Greater Cape Floristic Region, South Africa

    DOE PAGES

    Copeland, Sandi R.; Cawthra, Hayley C.; Fisher, Erich C.; ...

    2016-04-16

    Middle Stone Age sites located within the Greater Cape Floristic Region on the South African southern coast have material culture with early evidence for key modern human behaviors such as projectile weaponry, large animal hunting, and symbolic behavior. In order to interpret how and why these changes evolved, it is necessary to understand their ecological context as it has direct relevance to foraging behavior. During periods of lowered sea level, a largely flat and vast expanse of land existed south of the modern coastline, but it is now submerged by higher sea levels. This exposed area, the Paleo-Agulhas Plain, likelymore » created an ecological context unlike anything in the region today, as evidenced by fossil assemblages dominated by migratory ungulates. One hypothesis is that the Paleo-Agulhas Plain supported a migration ecosystem of large grazers driven by summer rainfall, producing palatable forage during summer in the east, and winter rainfall, producing palatable forage during winter in the west. Furthermore, ungulates may have been moving from the coastal plain in the south to the interior north of the Cape Fold Mountains, as observed for elephants in historic times.« less

  6. Returning to practice.

    PubMed

    Holland, S

    1994-03-01

    All too often health visitors seeking to return to practice following a career break are met with negative response, writes Stevie Holland. Here she recounts the words and experiences of some of the health visitors who enrolled on the HVA's open learning 'Return to practice' courses in recent years. The health visiting profession needs to encourage the enthusiasm and innovation of returners if it is to survive in today's political climate, she warns.

  7. Assured crew return vehicle

    NASA Technical Reports Server (NTRS)

    Cerimele, Christopher J. (Inventor); Ried, Robert C. (Inventor); Peterson, Wayne L. (Inventor); Zupp, George A., Jr. (Inventor); Stagnaro, Michael J. (Inventor); Ross, Brian P. (Inventor)

    1991-01-01

    A return vehicle is disclosed for use in returning a crew to Earth from low earth orbit in a safe and relatively cost effective manner. The return vehicle comprises a cylindrically-shaped crew compartment attached to the large diameter of a conical heat shield having a spherically rounded nose. On-board inertial navigation and cold gas control systems are used together with a de-orbit propulsion system to effect a landing near a preferred site on the surface of the Earth. State vectors and attitude data are loaded from the attached orbiting craft just prior to separation of the return vehicle.

  8. Comet nucleus and asteroid sample return missions

    NASA Technical Reports Server (NTRS)

    Melton, Robert G.; Thompson, Roger C.; Starchville, Thomas F., Jr.; Adams, C.; Aldo, A.; Dobson, K.; Flotta, C.; Gagliardino, J.; Lear, M.; Mcmillan, C.

    1992-01-01

    During the 1991-92 academic year, the Pennsylvania State University has developed three sample return missions: one to the nucleus of comet Wild 2, one to the asteroid Eros, and one to three asteroids located in the Main Belt. The primary objective of the comet nucleus sample return mission is to rendezvous with a short period comet and acquire a 10 kg sample for return to Earth. Upon rendezvous with the comet, a tethered coring and sampler drill will contact the surface and extract a two-meter core sample from the target site. Before the spacecraft returns to Earth, a monitoring penetrator containing scientific instruments will be deployed for gathering long-term data about the comet. A single asteroid sample return mission to the asteroid 433 Eros (chosen for proximity and launch opportunities) will extract a sample from the asteroid surface for return to Earth. To limit overall mission cost, most of the mission design uses current technologies, except the sampler drill design. The multiple asteroid sample return mission could best be characterized through its use of future technology including an optical communications system, a nuclear power reactor, and a low-thrust propulsion system. A low-thrust trajectory optimization code (QuickTop 2) obtained from the NASA LeRC helped in planning the size of major subsystem components, as well as the trajectory between targets.

  9. Optimization of return electrodes in neurostimulating arrays

    NASA Astrophysics Data System (ADS)

    Flores, Thomas; Goetz, Georges; Lei, Xin; Palanker, Daniel

    2016-06-01

    Objective. High resolution visual prostheses require dense stimulating arrays with localized inputs of individual electrodes. We study the electric field produced by multielectrode arrays in electrolyte to determine an optimal configuration of return electrodes and activation sequence. Approach. To determine the boundary conditions for computation of the electric field in electrolyte, we assessed current dynamics using an equivalent circuit of a multielectrode array with interleaved return electrodes. The electric field modeled with two different boundary conditions derived from the equivalent circuit was then compared to measurements of electric potential in electrolyte. To assess the effect of return electrode configuration on retinal stimulation, we transformed the computed electric fields into retinal response using a model of neural network-mediated stimulation. Main results. Electric currents at the capacitive electrode-electrolyte interface redistribute over time, so that boundary conditions transition from equipotential surfaces at the beginning of the pulse to uniform current density in steady state. Experimental measurements confirmed that, in steady state, the boundary condition corresponds to a uniform current density on electrode surfaces. Arrays with local return electrodes exhibit improved field confinement and can elicit stronger network-mediated retinal response compared to those with a common remote return. Connecting local return electrodes enhances the field penetration depth and allows reducing the return electrode area. Sequential activation of the pixels in large monopolar arrays reduces electrical cross-talk and improves the contrast in pattern stimulation. Significance. Accurate modeling of multielectrode arrays helps optimize the electrode configuration to maximize the spatial resolution, contrast and dynamic range of retinal prostheses.

  10. Power and energy dissipation in subsequent return strokes as predicted by a new return stroke model

    NASA Technical Reports Server (NTRS)

    Cooray, Vernon

    1991-01-01

    Recently, Cooray introduced a new return stroke model which is capable of predicting the temporal behavior of the return stroke current and the return stroke velocity as a function of the height along the return stroke channel. The authors employed this model to calculate the power and energy dissipation in subsequent return strokes. The results of these calculations are presented here. It was concluded that a large fraction of the total energy available for the dart leader-subsequent stroke process is dissipated in the dart leader stage. The peak power per unit length dissipated in a subsequent stroke channel element decreases with increasing height of that channel element from ground level. For a given channel element, the peak power dissipation increases with increasing current in that channel element. The peak electrical power dissipation in a typical subsequent return stroke is about 1.5 times 10(exp 11) W. The energy dissipation in a subsequent stroke increases with increasing current in the return stroke channel, and for a typical subsequent stroke, the energy dissipation per unit length is about 5.0 times 10(exp 3) J/m.

  11. Assured crew return capability Crew Emergency Return Vehicle (CERV) avionics

    NASA Technical Reports Server (NTRS)

    Myers, Harvey Dean

    1990-01-01

    The Crew Emergency Return Vehicle (CERV) is being defined to provide Assured Crew Return Capability (ACRC) for Space Station Freedom. The CERV, in providing the standby lifeboat capability, would remain in a dormat mode over long periods of time as would a lifeboat on a ship at sea. The vehicle must be simple, reliable, and constantly available to assure the crew's safety. The CERV must also provide this capability in a cost effective and affordable manner. The CERV Project philosophy of a simple vehicle is to maximize its useability by a physically deconditioned crew. The vehicle reliability goes unquestioned since, when needed, it is the vehicle of last resort. Therefore, its systems and subsystems must be simple, proven, state-of-the-art technology with sufficient redundancy to make it available for use as required for the life of the program. The CERV Project Phase 1'/2 Request for Proposal (RFP) is currently scheduled for release on October 2, 1989. The Phase 1'/2 effort will affirm the existing project requirements or amend and modify them based on a thorough evaluation of the contractor(s) recommendations. The system definition phase, Phase 2, will serve to define CERV systems and subsystems. The current CERV Project schedule has Phase 2 scheduled to begin October 1990. Since a firm CERV avionics design is not in place at this time, the treatment of the CERV avionics complement for the reference configuration is not intended to express a preference with regard to a system or subsystem.

  12. Fluctuation behaviors of financial return volatility duration

    NASA Astrophysics Data System (ADS)

    Niu, Hongli; Wang, Jun; Lu, Yunfan

    2016-04-01

    It is of significantly crucial to understand the return volatility of financial markets because it helps to quantify the investment risk, optimize the portfolio, and provide a key input of option pricing models. The characteristics of isolated high volatility events above certain threshold in price fluctuations and the distributions of return intervals between these events arouse great interest in financial research. In the present work, we introduce a new concept of daily return volatility duration, which is defined as the shortest passage time when the future volatility intensity is above or below the current volatility intensity (without predefining a threshold). The statistical properties of the daily return volatility durations for seven representative stock indices from the world financial markets are investigated. Some useful and interesting empirical results of these volatility duration series about the probability distributions, memory effects and multifractal properties are obtained. These results also show that the proposed stock volatility series analysis is a meaningful and beneficial trial.

  13. Electrostatic Return of Contaminants

    NASA Technical Reports Server (NTRS)

    Rantanen, R.; Gordon, T.

    2003-01-01

    A Model has been developed capable of calculating the electrostatic return of spacecraft-emitted molecules that are ionized and attracted back to the spacecraft by the spacecraft electric potential on its surfaces. The return of ionized contaminant molecules to charged spacecraft surfaces is very important to all altitudes. It is especially important at geosynchronous and interplanetary environments, since it may be the only mechanism by which contaminants can degrade a surface. This model is applicable to all altitudes and spacecraft geometries. In addition to results of the model will be completed to cover a wide range of potential space systems.

  14. Return to Play

    ERIC Educational Resources Information Center

    Mangan, Marianne

    2013-01-01

    Call it physical activity, call it games, or call it play. Whatever its name, it's a place we all need to return to. In the physical education, recreation, and dance professions, we need to redesign programs to address the need for and want of play that is inherent in all of us.

  15. Sustainable Mars Sample Return

    NASA Technical Reports Server (NTRS)

    Alston, Christie; Hancock, Sean; Laub, Joshua; Perry, Christopher; Ash, Robert

    2011-01-01

    The proposed Mars sample return mission will be completed using natural Martian resources for the majority of its operations. The system uses the following technologies: In-Situ Propellant Production (ISPP), a methane-oxygen propelled Mars Ascent Vehicle (MAV), a carbon dioxide powered hopper, and a hydrogen fueled balloon system (large balloons and small weather balloons). The ISPP system will produce the hydrogen, methane, and oxygen using a Sabatier reactor. a water electrolysis cell, water extracted from the Martian surface, and carbon dioxide extracted from the Martian atmosphere. Indigenous hydrogen will fuel the balloon systems and locally-derived methane and oxygen will fuel the MAV for the return of a 50 kg sample to Earth. The ISPP system will have a production cycle of 800 days and the estimated overall mission length is 1355 days from Earth departure to return to low Earth orbit. Combining these advanced technologies will enable the proposed sample return mission to be executed with reduced initial launch mass and thus be more cost efficient. The successful completion of this mission will serve as the next step in the advancement of Mars exploration technology.

  16. Mars Earth Return Vehicle (MERV) Propulsion Options

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; McGuire, Melissa L.; Burke, Laura; Fincannon, James; Warner, Joe; Williams, Glenn; Parkey, Thomas; Colozza, Tony; Fittje, Jim; Martini, Mike; Packard, Tom; Hemminger, Joseph; Gyekenyesi, John

    2010-01-01

    The COMPASS Team was tasked with the design of a Mars Sample Return Vehicle. The current Mars sample return mission is a joint National Aeronautics and Space Administration (NASA) and European Space Agency (ESA) mission, with ESA contributing the launch vehicle for the Mars Sample Return Vehicle. The COMPASS Team ran a series of design trades for this Mars sample return vehicle. Four design options were investigated: Chemical Return /solar electric propulsion (SEP) stage outbound, all-SEP, all chemical and chemical with aerobraking. The all-SEP and Chemical with aerobraking were deemed the best choices for comparison. SEP can eliminate both the Earth flyby and the aerobraking maneuver (both considered high risk by the Mars Sample Return Project) required by the chemical propulsion option but also require long low thrust spiral times. However this is offset somewhat by the chemical/aerobrake missions use of an Earth flyby and aerobraking which also take many months. Cost and risk analyses are used to further differentiate the all-SEP and Chemical/Aerobrake options.

  17. Assured Crew Return Vehicle

    NASA Technical Reports Server (NTRS)

    Stone, D. A.; Craig, J. W.; Drone, B.; Gerlach, R. H.; Williams, R. J.

    1991-01-01

    The developmental status is discussed regarding the 'lifeboat' vehicle to enhance the safety of the crew on the Space Station Freedom (SSF). NASA's Assured Crew Return Vehicle (ACRV) is intended to provide a means for returning the SSF crew to earth at all times. The 'lifeboat' philosophy is the key to managing the development of the ACRV which further depends on matrixed support and total quality management for implementation. The risk of SSF mission scenarios are related to selected ACRV mission requirements, and the system and vehicle designs are related to these precepts. Four possible ACRV configurations are mentioned including the lifting-body, Apollo shape, Discoverer shape, and a new lift-to-drag concept. The SCRAM design concept is discussed in detail with attention to the 'lifeboat' philosophy and requirements for implementation.

  18. The Mechanism Underlying Inhibition of Saccadic Return

    ERIC Educational Resources Information Center

    Ludwig, Casimir J. H.; Farrell, Simon; Ellis, Lucy A.; Gilchrist, Iain D.

    2009-01-01

    Human observers take longer to re-direct gaze to a previously fixated location. Although there has been some exploration of the characteristics of inhibition of saccadic return (ISR), the exact mechanisms by which ISR operates are currently unknown. In the framework of accumulation models of response times, in which evidence is integrated over…

  19. Return to sport following amputation.

    PubMed

    Matthews, D; Sukeik, M; Haddad, F

    2014-08-01

    Amputation in athletes has a substantial impact on lifestyle and sporting activity, as well as self-perception and quality of life. The impact of limb loss on athletic ability will vary depending on the cause of amputation and the anatomical location of the amputation. The use of sporting activity for rehabilitation of amputees was first introduced in 1944 at Stoke Mandeville Hospital. The first international paralympic games were founded in 1960. Following these events the opportunity to participate in sport following limb loss has increased significantly. Sport participation has been aided by the development of sporting prostheses, however multiple factors will determine the exact prosthesis used. These include the nature of the sporting activity as well as the level of the amputation. The biomechanics involved in walking and running are altered following the loss of a limb or part thereof. This can cause subsequent degenerative changes within the remaining joints on the amputated limb as well as the contralateral limb. Factors affecting return to sporting activity are multivariate and inter-related, including patient factors, surgical factors, nature and level of the sporting activity and prosthetic factors. The authors review current literature, detail predictive factors of return to sport and the physical and psychosocial impact on patients following limb amputation.

  20. Return to work (RTW) after head injury.

    PubMed

    McMordie, W R; Barker, S L; Paolo, T M

    1990-01-01

    This study explored return to work (RTW) after head injury from survey data on 177 cases of head injury. Although 45% of the sample study did engage in some work-related activity only 19% were in competitive employment positions. Factors which were related to RTW after head injury were: age when injured, sex, length of loss of consciousness and Likert ratings of learning, motor and ambulation impairment. Many of those who did return to competitive employment did so in less demanding positions than held pre-injury. Limitations of the current study and suggestions for future research are ventured.

  1. Returns to Education in Bangladesh

    ERIC Educational Resources Information Center

    Asadullah, Mohammad Niaz

    2006-01-01

    This paper reports labour market returns to education in Bangladesh using data from recent nationwide household survey. Returns are estimated separately for rural and urban samples, males, females and private-sector employees. Substantial heterogeneity in returns is observed; for example, estimates are higher for urban (than rural sample) and…

  2. Energy Vs. Productivity: Diminishing Returns

    ERIC Educational Resources Information Center

    MOSAIC, 1975

    1975-01-01

    Energy invested in corn production is compared with food energy returned in calculations by David Pimentel at Cornell University. The rate of return is falling off sharply in this already energy-intensive agriculture. Increased energy input, in the form of fertilizer, would yield far greater returns where agriculture is less sophisticated.…

  3. Titan Science Return Quantification

    NASA Technical Reports Server (NTRS)

    Weisbin, Charles R.; Lincoln, William

    2014-01-01

    Each proposal for a NASA mission concept includes a Science Traceability Matrix (STM), intended to show that what is being proposed would contribute to satisfying one or more of the agency's top-level science goals. But the information traditionally provided cannot be used directly to quantitatively compare anticipated science return. We added numerical elements to NASA's STM and developed a software tool to process the data. We then applied this methodology to evaluate a group of competing concepts for a proposed mission to Saturn's moon, Titan.

  4. 21 CFR 211.204 - Returned drug products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Returned drug products. 211.204 Section 211.204 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Returned and Salvaged...

  5. 21 CFR 211.204 - Returned drug products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Returned drug products. 211.204 Section 211.204 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Returned and Salvaged...

  6. 21 CFR 211.204 - Returned drug products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Returned drug products. 211.204 Section 211.204 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Returned and Salvaged...

  7. 21 CFR 211.204 - Returned drug products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Returned drug products. 211.204 Section 211.204 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Returned and Salvaged...

  8. 21 CFR 211.204 - Returned drug products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Returned drug products. 211.204 Section 211.204 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Returned and Salvaged...

  9. Returning Samples from Enceladus

    NASA Astrophysics Data System (ADS)

    Tsou, P.; Kanik, I.; Brownlee, D.; McKay, C.; Anbar, A.; Glavin, D.; Yano, H.

    2012-12-01

    From the first half century of space exploration, we have obtained samples only from the Moon, comet Wild 2, the Solar Wind and the asteroid Itokawa. The in-depth analyses of these samples in terrestrial laboratories have yielded profound knowledge that could not have been obtained without the returned samples. While obtaining samples from Solar System bodies is crucial science, it is rarely done due to cost and complexity. Cassini's discovery of geysers on Enceladus and organic materials, indicate that there is an exceptional opportunity and science rational to do a low-cost flyby sample return mission, similar to what was done by the Stardust. The earliest low cost possible flight opportunity is the next Discovery Mission [Tsou et al 2012]. Enceladus Plume Discovery - While Voyager provided evidence for young surfaces on Enceladus, the existence of Enceladus plumes was discovered by Cassini. Enceladus and comets are the only known solar system bodies that have jets enabling sample collection without landing or surface contact. Cassini in situ Findings -Cassini's made many discoveries at Saturn, including the break up of large organics in the plumes of Enceladus. Four prime criteria for habitability are liquid water, a heat source, organics and nitrogen [McKay et al. 2008, Waite et al. 2009, Postberg et al. 2011]. Out of all the NASA designated habitability targets, Enceladus is the single body that presents evidence for all four criteria. Significant advancement in the exploration of the biological potential of Enceladus can be made on returned samples in terrestrial laboratories where the full power of state-of-the-art laboratory instrumentation and procedures can be used. Without serious limits on power, mass or even cost, terrestrial laboratories provide the ultimate in analytical capability, adaptability, reproducibility and reliability. What Questions can Samples Address? - Samples collected from the Enceladus plume will enable a thorough and replicated

  10. Return to Space

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This video documents the preparations for Shuttle Flight STS-26 with Shuttle Discovery, NASA's return to manned space flight after the Challenger disaster. Footage and descriptions document such changes to the new Shuttle as new joints, improved insulation, and added O-rings to the solid rocket boosters; new safety hardware and procedures such as parachute and sidewire evacuations during liftoff, and new pressure suits; modified landing gear, brakes, and nose wheel steering, as well as a modified landing runway. Also profiled are the 5 member crew of all veteran Shuttle astronauts, the TDRS 3 Satellite to be released from the cargo bay in orbit, and 11 commercial and student experiments to be performed during the mission.

  11. Dealing with returned manuscripts.

    PubMed

    Peh, W C G; Ng, K H

    2009-11-01

    It is useful for authors to learn to deal with returned manuscripts with a rejection decision or a request for revision. Common reasons for rejection include contents outside the scope of the journal or inappropriate for the journal, incomplete submission, poor methodology, faulty experimental design, major flaws in the interpretation of results, extremely poor writing, and duplicated or plagiarised work. Authors should use the editor's and reviewers' comments to improve their manuscripts and resubmit elsewhere. Common reasons for revision requests include minor faults in the methodology, minor inaccuracies in data, inconsistencies among different sections of the manuscript, faulty deductions, data that do not support the conclusions, excessive data or text, poor or excessive illustrations, and poor but salvageable writing. A request for revision should be viewed positively, as it means that there is a possibility that the manuscript may still be potentially publishable, provided that all the editor's and reviewers' comments are addressed.

  12. Awaiting Halley's Return

    NASA Astrophysics Data System (ADS)

    Heyn, Herman M.

    2004-01-01

    When Comet Halley perihelioned in early 1986, there were people still around who had witnessed its previous, 1910 apparition. )Then there is Mark Twain, who was born under the comet in 1835, wished for his demise upon its return, and died one day after it perihelioned in 1910!( I so enjoyed my 1986 view of Halley, that I decided I would like to be among those who see it again when it perihelions in 2061. The big problem with this ambition is that I would need to live to a Guinness Book of World's Records age of 131 years. Now, thanks to Randy Showstack's In Brief news note, ``Farthest, faintest detection of a comet'' (Eos, 16 September 2003), I have been handed a fallback position which, literally, I may be able to live with: a telescopic photo of Halley at aphelion.

  13. Returning to freud.

    PubMed

    Chessick, Richard D

    2010-01-01

    In this article I attempt to renew interest in the importance of Freud's work for both the practice of psychoanalysis and in the training of psychoanalysts. I hope to stimulate readers to return to Freud's writings in detail, which seem to be increasingly neglected these days both in training and in the many conflicting contemporary models of psychoanalysis. I propose that the identity of psychoanalysis can still be based on Freud's work, and his approach can form a fundamental center from which there are various channels of divergence that may be useful when the patient seems to need them. But the centerpiece of our training and our orientation, I suggest, should be the basic principles spelled out in Freud's numerous volumes, in spite of the many changes and contradictions and even outright mistakes and cultural blindness he displays in some instances. I proceed to review some of these basic principles in the hope of persuading the reader to return to Freud again. I present these with some commentary from my own 50 years of clinical experience. I briefly review the clinical cornerstones of Freud's approach as developed in his early books, his controversial papers on technique, and his later emendations, which constitute the actual reality of Freud at work in psychoanalysis (that sometimes--and sometimes wisely--violates his papers on technique), and I discuss his notion of curative factors in psychoanalysis. All of this is to revive an interest in Freud's thought and to emphasize the lasting value of his work, both in its contemporary clinical relevance and as the proposed foundation stone of our identity as psychoanalysts.

  14. 11. VIEW OF A SITE RETURN WEAPONS COMPONENT. SITE RETURNS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. VIEW OF A SITE RETURN WEAPONS COMPONENT. SITE RETURNS WERE NUCLEAR WEAPONS SHIPPED TO THE ROCKY FLATS PLANT FROM THE NUCLEAR WEAPON STOCKPILE FOR RETIREMENT, TESTING, OR UPGRADING. FISSILE MATERIALS (PLUTONIUM, URANIUM, ETC.) AND RARE MATERIALS (BERYLLIUM) WERE RECOVERED FOR REUSE, AND THE REMAINDER WAS DISPOSED. (8/7/62) - Rocky Flats Plant, Plutonium Fabrication, Central section of Plant, Golden, Jefferson County, CO

  15. Documenting investment policy boosts safety, returns.

    PubMed

    Kovener, R R

    1992-02-01

    The process and responsibility for a healthcare organization's investment decisions should be clearly documented in an investment policy. Any investment policy should contain at least seven elements: how investments relate to the organization's mission; responsibilities of involved parties; long- and short-term objectives; desired balance between return and risk; proportions of a portfolio held in stocks, bonds, and other investments; disposition of donated assets; desired investment reports; and the process for keeping the policy current.

  16. Christmas Island birds returning

    NASA Astrophysics Data System (ADS)

    Six months after their mass exodus, birds are beginning to return to Christmas Island. Roughly 17 million birds, almost the entire adult bird population, either perished or fled their mid-Pacific atoll home last autumn, leaving behind thousands of nestlings to starve (Eos, April 5, 1983, p. 131). It is believed that the strong El Niño altered the ecology of the surrounding waters and forced the birds to flee. Christmas Island is the world's largest coral atoll.“Ocean and atmosphere scientists are unsure of future directions for the El Niño conditions and cannot now predict what will happen to the birds in the coming months,” said Ralph W. Schreiber, curator of ornithology at the Natural History Museum of Los Angeles County in California. Heisthe ornithologist who discovered the disappearance. “The recovery of the bird populations depends on the food supply in the waters surrounding the island.” The island's birds feed exclusively on small fish and squid.

  17. The Point of No Return

    PubMed Central

    Logan, Gordon D.

    2015-01-01

    Bartlett (1958) described the point of no return as a point of irrevocable commitment to action, which was preceded by a period of gradually increasing commitment. As such, the point of no return reflects a fundamental limit on the ability to control thought and action. I review the literature on the point of no return, taking three perspectives. First, I consider the point of no return from the perspective of the controlled act, as a locus in the architecture and anatomy of the underlying processes. I review experiments from the stop-signal paradigm that suggest that the point of no return is located late in the response system. Then I consider the point of no return from the perspective of the act of control that tries to change the controlled act before it becomes irrevocable. From this perspective, the point of no return is a point in time that provides enough “lead time” for the act of control to take effect. I review experiments that measure the response time to the stop signal as the lead time required for response inhibition in the stop-signal paradigm. Finally, I consider the point of no return in hierarchically controlled tasks, in which there may be many points of no return at different levels of the hierarchy. I review experiments on skilled typing that suggest different points of no return for the commands that determine what is typed and the countermands that inhibit typing, with increasing commitment to action the lower the level in the hierarchy. I end by considering the point of no return in perception and thought as well as action. PMID:25633089

  18. Capital Structure and Stock Returns

    ERIC Educational Resources Information Center

    Welch, Ivo

    2004-01-01

    U.S. corporations do not issue and repurchase debt and equity to counteract the mechanistic effects of stock returns on their debt-equity ratios. Thus over one- to five-year horizons, stock returns can explain about 40 percent of debt ratio dynamics. Although corporate net issuing activity is lively and although it can explain 60 percent of debt…

  19. Workers' Compensation, Return to Work, and Lumbar Fusion for Spondylolisthesis.

    PubMed

    Anderson, Joshua T; Haas, Arnold R; Percy, Rick; Woods, Stephen T; Ahn, Uri M; Ahn, Nicholas U

    2016-01-01

    Lumbar fusion for spondylolisthesis is associated with consistent outcomes in the general population. However, workers' compensation is a risk factor for worse outcomes. Few studies have evaluated prognostic factors within this clinically distinct population. The goal of this study was to identify prognostic factors for return to work among patients with workers' compensation claims after fusion for spondylolisthesis. The authors used International Classification of Diseases, Ninth Revision, and Current Procedural Terminology codes to identify 686 subjects from the Ohio Bureau of Workers' Compensation who underwent fusion for spondylolisthesis from 1993 to 2013. Positive return to work status was recorded in patients who returned to work within 2 years of fusion and remained working for longer than 6 months. The criteria for return to work were met by 29.9% (n=205) of subjects. The authors used multivariate logistic regression analysis to identify prognostic factors for return to work. Negative preoperative prognostic factors for postoperative return to work included: out of work for longer than 1 year before fusion (P<.001; odds ratio [OR], 0.16); depression (P=.007; OR<0.01); long-term opioid analgesic use (P=.006; OR, 0.41); lumbar stenosis (P=.043; OR, 0.55); and legal representation (P=.042; OR, 0.63). Return to work rates associated with these factors were 9.7%, 0.0%, 10.0%, 29.2%, and 25.0%, respectively. If these subjects were excluded, the return to work rate increased to 60.4%. The 70.1% (n=481) of subjects who did not return to work had markedly worse outcomes, shown by higher medical costs, chronic opioid dependence, and higher rates of failed back syndrome, total disability, and additional surgery. Psychiatric comorbidity increased after fusion but was much higher in those who did not return to work. Future studies are needed to identify how to better facilitate return to work among similar patients with workers' compensation claims.

  20. Mars Sample Return Using Solar Sail Propulsion

    NASA Technical Reports Server (NTRS)

    Johnson, Les; Macdonald, Malcolm; Mcinnes, Colin; Percy, Tom

    2012-01-01

    Many Mars Sample Return (MSR) architecture studies have been conducted over the years. A key element of them is the Earth Return Stage (ERS) whose objective is to obtain the sample from the Mars Ascent Vehicle (MAV) and return it safely to the surface of the Earth. ERS designs predominantly use chemical propulsion [1], incurring a significant launch mass penalty due to the low specific impulse of such systems coupled with the launch mass sensitivity to returned mass. It is proposed to use solar sail propulsion for the ERS, providing a high (effective) specific impulse propulsion system in the final stage of the multi-stage system. By doing so to the launch mass of the orbiter mission can be significantly reduced and hence potentially decreasing mission cost. Further, solar sailing offers a unique set of non-Keplerian low thrust trajectories that may enable modifications to the current approach to designing the Earth Entry Vehicle by potentially reducing the Earth arrival velocity. This modification will further decrease the mass of the orbiter system. Solar sail propulsion uses sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like surface made of a lightweight, reflective material. The continuous photonic pressure provides propellantless thrust to conduct orbital maneuvering and plane changes more efficiently than conventional chemical propulsion. Because the Sun supplies the necessary propulsive energy, solar sails require no onboard propellant, thus reducing system mass. This technology is currently at TRL 7/8 as demonstrated by the 2010 flight of the Japanese Aerospace Exploration Agency, JAXA, IKAROS mission. [2

  1. FRS Geospatial Return File Format

    EPA Pesticide Factsheets

    The Geospatial Return File Format describes format that needs to be used to submit latitude and longitude coordinates for use in Envirofacts mapping applications. These coordinates are stored in the Geospatail Reference Tables.

  2. Another Kind of Returning Student.

    ERIC Educational Resources Information Center

    Chandler, Judith B.

    1984-01-01

    Discusses the needs of women who are returning to school for adult basic education. Provides suggestions for meeting the needs of this group in terms of professional action, counselor education, teacher training, grants, financial support, publication, and volunteerism. (JAC)

  3. Principles of rehabilitation and return to sports following injury.

    PubMed

    Fournier, Magali

    2015-04-01

    Rehabilitation of an athlete can present its own challenges. Few protocols are available to guide physicians in proper return to sport. Rehabilitation after foot and ankle sport injury can be categorized into 3 different stages but should also be individualized. The focus of this article is to help the treating physician in creating a protocol to safely return an injured athlete back to sport based on current literature and principles.

  4. Phootprint - A Phobos sample return mission study

    NASA Astrophysics Data System (ADS)

    Koschny, Detlef; Svedhem, Håkan; Rebuffat, Denis

    Introduction ESA is currently studying a mission to return a sample from Phobos, called Phootprint. This study is performed as part of ESA’s Mars Robotic Exploration Programme. Part of the mission goal is to prepare technology needed for a sample return mission from Mars itself; the mission should also have a strong scientific justification, which is described here. 1. Science goal The main science goal of this mission will be to Understand the formation of the Martian moons Phobos and put constraints on the evolution of the solar system. Currently, there are several possibilities for explaining the formation of the Martian moons: (a) co-formation with Mars (b) capture of objects coming close to Mars (c) Impact of a large body onto Mars and formation from the impact ejecta The main science goal of this mission is to find out which of the three scenarios is the most probable one. To do this, samples from Phobos would be returned to Earth and analyzed with extremely high precision in ground-based laboratories. An on-board payload is foreseen to provide information to put the sample into the necessary geological context. 2. Mission Spacecraft and payload will be based on experience gained from previous studies to Martian moons and asteroids. In particular the Marco Polo and MarcoPolo-R asteroid sample return mission studies performed at ESA were used as a starting point. Currently, industrial studies are ongoing. The initial starting assumption was to use a Soyuz launcher. Uunlike the initial Marco Polo and MarcoPolo-R studies to an asteroid, a transfer stage will be needed. Another main difference to an asteroid mission is the fact that the spacecraft actually orbits Mars, not Phobos or Deimos. It is possible to select a spacecraft orbit, which in a Phobos- or Deimos-centred reference system would give an ellipse around the moon. The following model payload is currently foreseen: - Wide Angle Camera, - Narrow Angle Camera, - Close-Up Camera, - Context camera for

  5. OSIRIS-REx, Returning the Asteroid Sample

    NASA Technical Reports Server (NTRS)

    Ajluni, Thomas, M.; Everett, David F.; Linn, Timothy; Mink, Ronald; Willcockson, William; Wood, Joshua

    2015-01-01

    This paper addresses the technical aspects of the sample return system for the upcoming Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission. The overall mission design and current implementation are presented as an overview to establish a context for the technical description of the reentry and landing segment of the mission.The prime objective of the OSIRIS-REx mission is to sample a primitive, carbonaceous asteroid and to return that sample to Earth in pristine condition for detailed laboratory analysis. Targeting the near-Earth asteroid Bennu, the mission launches in September 2016 with an Earth reentry date of September 24, 2023.OSIRIS-REx will thoroughly characterize asteroid Bennu providing knowledge of the nature of near-Earth asteroids that is fundamental to understanding planet formation and the origin of life. The return to Earth of pristine samples with known geologic context will enable precise analyses that cannot be duplicated by spacecraft-based instruments, revolutionizing our understanding of the early Solar System. Bennu is both the most accessible carbonaceous asteroid and one of the most potentially Earth-hazardous asteroids known. Study of Bennu addresses multiple NASA objectives to understand the origin of the Solar System and the origin of life and will provide a greater understanding of both the hazards and resources in near-Earth space, serving as a precursor to future human missions to asteroids.This paper focuses on the technical aspects of the Sample Return Capsule (SRC) design and concept of operations, including trajectory design and reentry retrieval. Highlights of the mission are included below.The OSIRIS-REx spacecraft provides the essential functions for an asteroid characterization and sample return mission: attitude control propulsion power thermal control telecommunications command and data handling structural support to ensure successful

  6. Phobos Sample Return - a mission to return a sample from a Martian moon

    NASA Astrophysics Data System (ADS)

    Korablev, Oleg; Koschny, Detlef; Voirin, Thomas

    2016-07-01

    Phobos Sample Return is a mission currently studied by the European Space Agency (ESA), in collaboration with Russia. The main scientific goal is to return about 100 g of sample from the Martian moon Phobos. The current ESA Phase A study has identified a feasible mission with a launch in Sep 2024. It would arrive at Mars in Aug 2025, land on Phobos in April 2026, escape from Mars in September 2026 and bring back a sample to Earth in the summer of 2027. The spacecraft consists of a Propulsion Module (PM), a Lander Module (LM), an Earth Return Vehicle (ERV), and an Earth Reentry Capsule (ERC). A sampling Acquisition Transfer and Containment system (SATCS) composed of a robotic arm, sampling and sealing mechanism is responsible for the surface sampling operations. The PM is responsible for bringing the whole S/C composite into Mars orbit. The Lander/ERV/ERC composite would separate from the PM after Mars Orbit Insertion. After a phase of 1 month spent observing Deimos from a quasi-satellite orbit, the composite would be transferred to Phobos' vicinity for an extensive phase of detailed surface characterization which would allow the selection of the candidate landing site. The S/C would then land on Phobos and remain on the surface for a few weeks. After some initial characterization of the surroundings, the sample would be taken and transferred to the ERC. The ERV with the ERC would leave Phobos and return to Earth; the LM would continue performing surface science on Phobos until several weeks after ERV departure. Shortly before atmospheric entry, the ERC would separate from the ERV to enter the atmosphere safely. After recovery, the sample would be returned into an analysis lab. This presentation will give the latest status of the mission study, and outline future activities.

  7. Return to work following ileostomy.

    PubMed

    Whates, P D; Irving, M

    1984-08-01

    The experiences of 1033 members of the 51 English divisions of the Ileostomy Association of Great Britain and Ireland have been analysed in respect of their return to work after construction of an ileostomy. Although there was a fall in the number of patients returning to work after operation this was often for reasons unrelated to surgery. The majority of those returning to work resumed work with the same employer and usually in the same post. Fifty-nine (5.7 per cent) patients began work for the first time after operation, including 33 (3.2 per cent) who were previously inactive although of working age. Analysis of occupational class shows that, although a number of patients initially resumed work within a lower class, once established in employment successful career advancement was possible. Problems in the gaining or resumption of employment were reported by 56 (5.4 per cent) patients. In 22 (2.1 per cent) patients, almost all approaching or above retirement age, successful surgery resulted in a decision not to return to employment. An ileostomy is no barrier to successful return to work in nearly all occupations, and is accomplished by the majority of patients without major difficulty.

  8. Radiation from lightning return strokes over a finitely conducting earth

    NASA Technical Reports Server (NTRS)

    Le Vine, D. M.; Gesell, L.; Kao, Michael

    1986-01-01

    The effects of the conductivity of the earth on radiation from lightning return strokes are examined theoretically using a piecewise linear transmission line model for the return stroke. First, calculations are made of the electric field radiated during the return stroke, and then this electric field is used to compute the response of conventional AM radio receivers and electric field change systems during the return stroke. The calculations apply to the entire transient waveform (they are not restricted to the initial portions of the return stroke) and yield fast field changes and RF radiation in agreement with measurements made during real lightning. This research was motivated by measurements indicating that a time delay exists between the time of arrival of the fast electric field change and the RF radiation from first return strokes. The time delay is on the order of 20 microsec for frequencies in the HF-UHF range for lightning in Florida. The time delay is obtained theoretically in this paper. It occurs when both the effects of attenuation due to conductivity of the earth, and the finite velocity of propagation of the current pulse up the return stroke channel, are taken into account in the model.

  9. The Benguela Current: An ecosystem of four components

    NASA Astrophysics Data System (ADS)

    Hutchings, L.; van der Lingen, C. D.; Shannon, L. J.; Crawford, R. J. M.; Verheye, H. M. S.; Bartholomae, C. H.; van der Plas, A. K.; Louw, D.; Kreiner, A.; Ostrowski, M.; Fidel, Q.; Barlow, R. G.; Lamont, T.; Coetzee, J.; Shillington, F.; Veitch, J.; Currie, J. C.; Monteiro, P. M. S.

    2009-12-01

    sulphur eruptions result from local and remote forcing, restricting the habitat available for pelagic and demersal fish species. The Luderitz-Orange River Cone is an intensive perennial upwelling cell where strong winds, high turbulence and strong offshore transport constitute a partial barrier to epipelagic fish species. Upwelling source water alters in salinity and oxygen, across this boundary zone. A decline in upwelling-favourable winds occurred between 1990 and 2005. The southern Benguela region is characterised by a pulsed, seasonal, wind-driven upwelling at discrete centres and warm Agulhas water offshore. High primary productivity forms a belt of enrichment along the coast, constrained by a front. Low-oxygen water, which only occurs close inshore, may adversely affect some resources. The west coast is primarily a nursery ground for several fish species which spawn on the Agulhas Bank and are transported by alongshore jet currents to the west coast. The Agulhas Bank forms the southern boundary of the Benguela system and it displays characteristics of both an upwelling and a temperate shallow shelf system, with seasonal stratification and mixing, coastal, shelf-edge and dynamic upwelling, moderate productivity and a well oxygenated shelf. A large biomass of fish occupies the Bank during the summer season, with some evidence for tight coupling between trophic levels. A cool ridge of upwelled water, with links to coastal upwelling and to the Agulhas Current, appears to play an important but poorly understood role affecting the distribution and productivity of pelagic fish. A boom in sardine and anchovy populations was accompanied by an eastward shift, followed by 5 years of poor recruitment by sardine but successful recruitment of anchovy, indicating changes in the early life-history patterns of these two species.

  10. Prediction of Stock Returns Based on Cross-Sectional Multivariable Model

    NASA Astrophysics Data System (ADS)

    Yamada, Shinya; Takahashi, Shinsuke; Funabashi, Motohisa

    A new prediction method of stock returns was constructed from a cross-sectional multivariable model where explanatory variables are current financial indexes and an explained variable is a future stock return. To achieve precise prediction, explanatory variables were appropriately selected over time based on various test statistics and optimization of a performance index of expected portfolio return. A long-short portfolio, in which stocks with high predicted return were bought and stocks with low predicted return were sold short, was constructed to evaluate the proposed method. The simulation test showed that the proposed prediction method was effective to achieve high portfolio performance.

  11. Sample Return Primer and Handbook

    NASA Technical Reports Server (NTRS)

    Barrow, Kirk; Cheuvront, Allan; Faris, Grant; Hirst, Edward; Mainland, Nora; McGee, Michael; Szalai, Christine; Vellinga, Joseph; Wahl, Thomas; Williams, Kenneth; Lee, Gentry; Duxbury, Thomas

    2007-01-01

    This three-part Sample Return Primer and Handbook provides a road map for conducting the terminal phase of a sample return mission. The main chapters describe element-by-element analyses and trade studies, as well as required operations plans, procedures, contingencies, interfaces, and corresponding documentation. Based on the experiences of the lead Stardust engineers, the topics include systems engineering (in particular range safety compliance), mission design and navigation, spacecraft hardware and entry, descent, and landing certification, flight and recovery operations, mission assurance and system safety, test and training, and the very important interactions with external support organizations (non-NASA tracking assets, landing site support, and science curation).

  12. 28 CFR 540.24 - Returned mail.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Returned mail. 540.24 Section 540.24... PERSONS IN THE COMMUNITY Correspondence § 540.24 Returned mail. Staff shall open and inspect for contraband all undelivered mail returned to an institution by the Post Office before returning it to...

  13. 28 CFR 540.24 - Returned mail.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Returned mail. 540.24 Section 540.24... PERSONS IN THE COMMUNITY Correspondence § 540.24 Returned mail. Staff shall open and inspect for contraband all undelivered mail returned to an institution by the Post Office before returning it to...

  14. 28 CFR 540.24 - Returned mail.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Returned mail. 540.24 Section 540.24... PERSONS IN THE COMMUNITY Correspondence § 540.24 Returned mail. Staff shall open and inspect for contraband all undelivered mail returned to an institution by the Post Office before returning it to...

  15. 28 CFR 540.24 - Returned mail.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Returned mail. 540.24 Section 540.24... PERSONS IN THE COMMUNITY Correspondence § 540.24 Returned mail. Staff shall open and inspect for contraband all undelivered mail returned to an institution by the Post Office before returning it to...

  16. 28 CFR 540.24 - Returned mail.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Returned mail. 540.24 Section 540.24... PERSONS IN THE COMMUNITY Correspondence § 540.24 Returned mail. Staff shall open and inspect for contraband all undelivered mail returned to an institution by the Post Office before returning it to...

  17. Uncertain Educational Returns in a Developing Economy

    ERIC Educational Resources Information Center

    Mohapatra, Sandeep; Luckert, Martin K.

    2012-01-01

    This paper estimates the distribution of educational returns by gender for India. While previous studies focus on mean returns, the variance of educational returns has important implications for policy-making and micro-level decision making with respect to education. If the variance of educational returns is large, it can leave large sections of…

  18. Biological Sterilization of Returned Mars Samples

    NASA Technical Reports Server (NTRS)

    Allen, C. C.; Albert, F. G.; Combie, J.; Bodnar, R. J.; Hamilton, V. E.; Jolliff, B. L.; Kuebler, K.; Wang, A.; Lindstrom, D. J.; Morris, P. A.

    1999-01-01

    Martian rock and soil, collected by robotic spacecraft, will be returned to terrestrial laboratories early in the next century. Current plans call for the samples to be immediately placed into biological containment and tested for signs of present or past life and biological hazards. It is recommended that "Controlled distribution of unsterilized materials from Mars should occur only if rigorous analyses determine that the materials do not constitute a biological hazard. If any portion of the sample is removed from containment prior to completion of these analyses it should first be sterilized." While sterilization of Mars samples may not be required, an acceptable method must be available before the samples are returned to Earth. The sterilization method should be capable of destroying a wide range of organisms with minimal effects on the geologic samples. A variety of biological sterilization techniques and materials are currently in use, including dry heat, high pressure steam, gases, plasmas and ionizing radiation. Gamma radiation is routinely used to inactivate viruses and destroy bacteria in medical research. Many commercial sterilizers use Co-60 , which emits gamma photons of 1.17 and 1.33 MeV. Absorbed doses of approximately 1 Mrad (10(exp 8) ergs/g) destroy most bacteria. This study investigates the effects of lethal doses of Co-60 gamma radiation on materials similar to those anticipated to be returned from Mars. The goals are to determine the gamma dose required to kill microorganisms in rock and soil samples and to determine the effects of gamma sterilization on the samples' isotopic, chemical and physical properties. Additional information is contained in the original extended abstract.

  19. Analysing Enterprise Returns on Training.

    ERIC Educational Resources Information Center

    Moy, Janelle; McDonald, Rod

    Recent Australian and overseas studies on evaluation of enterprises' return on training investment (ROTI) were reviewed to identify key issues in encouraging increased evaluation of training benefits by enterprises and successful approaches that may inform future "enterprise-friendly" studies of ROTI. It was concluded that more…

  20. Neurocognitive Performance: Returning to Competition

    ERIC Educational Resources Information Center

    McDaniel, Larry W.; McIntire, Kyle

    2010-01-01

    Athletes who suffer from concussions under report their symptoms in order to expedite their return to competition. Athletic trainers and coaches must be aware of what is going on with athletes, even if it means requiring them to refrain from competition. Ninety percent of concussions are minor and can be difficult to diagnosis. There is a lack of…

  1. Comet coma sample return instrument

    NASA Technical Reports Server (NTRS)

    Albee, A. L.; Brownlee, Don E.; Burnett, Donald S.; Tsou, Peter; Uesugi, K. T.

    1994-01-01

    The sample collection technology and instrument concept for the Sample of Comet Coma Earth Return Mission (SOCCER) are described. The scientific goals of this Flyby Sample Return are to return to coma dust and volatile samples from a known comet source, which will permit accurate elemental and isotopic measurements for thousands of individual solid particles and volatiles, detailed analysis of the dust structure, morphology, and mineralogy of the intact samples, and identification of the biogenic elements or compounds in the solid and volatile samples. Having these intact samples, morphologic, petrographic, and phase structural features can be determined. Information on dust particle size, shape, and density can be ascertained by analyzing penetration holes and tracks in the capture medium. Time and spatial data of dust capture will provide understanding of the flux dynamics of the coma and the jets. Additional information will include the identification of cosmic ray tracks in the cometary grains, which can provide a particle's process history and perhaps even the age of the comet. The measurements will be made with the same equipment used for studying micrometeorites for decades past; hence, the results can be directly compared without extrapolation or modification. The data will provide a powerful and direct technique for comparing the cometary samples with all known types of meteorites and interplanetary dust. This sample collection system will provide the first sample return from a specifically identified primitive body and will allow, for the first time, a direct method of matching meteoritic materials captured on Earth with known parent bodies.

  2. Comet coma sample return instrument

    NASA Astrophysics Data System (ADS)

    Albee, A. L.; Brownlee, Don E.; Burnett, Donald S.; Tsou, Peter; Uesugi, K. T.

    The sample collection technology and instrument concept for the Sample of Comet Coma Earth Return Mission (SOCCER) are described. The scientific goals of this Flyby Sample Return are to return to coma dust and volatile samples from a known comet source, which will permit accurate elemental and isotopic measurements for thousands of individual solid particles and volatiles, detailed analysis of the dust structure, morphology, and mineralogy of the intact samples, and identification of the biogenic elements or compounds in the solid and volatile samples. Having these intact samples, morphologic, petrographic, and phase structural features can be determined. Information on dust particle size, shape, and density can be ascertained by analyzing penetration holes and tracks in the capture medium. Time and spatial data of dust capture will provide understanding of the flux dynamics of the coma and the jets. Additional information will include the identification of cosmic ray tracks in the cometary grains, which can provide a particle's process history and perhaps even the age of the comet. The measurements will be made with the same equipment used for studying micrometeorites for decades past; hence, the results can be directly compared without extrapolation or modification. The data will provide a powerful and direct technique for comparing the cometary samples with all known types of meteorites and interplanetary dust. This sample collection system will provide the first sample return from a specifically identified primitive body and will allow, for the first time, a direct method of matching meteoritic materials captured on Earth with known parent bodies.

  3. Heat Pipe Blocks Return Flow

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1982-01-01

    Metal-foil reed valve in conventional slab-wick heat pipe limits heat flow to one direction only. With sink warmer than source, reed is forced closed and fluid returns to source side through annular transfer wick. When this occurs, wick slab on sink side of valve dries out and heat pipe ceases to conduct heat.

  4. Phobos Sample Return: Next Approach

    NASA Astrophysics Data System (ADS)

    Zelenyi, Lev; Martynov, Maxim; Zakharov, Alexander; Korablev, Oleg; Ivanov, Alexey; Karabadzak, George

    The Martian moons still remain a mystery after numerous studies by Mars orbiting spacecraft. Their study cover three major topics related to (1) Solar system in general (formation and evolution, origin of planetary satellites, origin and evolution of life); (2) small bodies (captured asteroid, or remnants of Mars formation, or reaccreted Mars ejecta); (3) Mars (formation and evolution of Mars; Mars ejecta at the satellites). As reviewed by Galimov [2010] most of the above questions require the sample return from the Martian moon, while some (e.g. the characterization of the organic matter) could be also answered by in situ experiments. There is the possibility to obtain the sample of Mars material by sampling Phobos: following to Chappaz et al. [2012] a 200-g sample could contain 10-7 g of Mars surface material launched during the past 1 mln years, or 5*10-5 g of Mars material launched during the past 10 mln years, or 5*1010 individual particles from Mars, quantities suitable for accurate laboratory analyses. The studies of Phobos have been of high priority in the Russian program on planetary research for many years. Phobos-88 mission consisted of two spacecraft (Phobos-1, Phobos-2) and aimed the approach to Phobos at 50 m and remote studies, and also the release of small landers (long-living stations DAS). This mission implemented the program incompletely. It was returned information about the Martian environment and atmosphere. The next profect Phobos Sample Return (Phobos-Grunt) initially planned in early 2000 has been delayed several times owing to budget difficulties; the spacecraft failed to leave NEO in 2011. The recovery of the science goals of this mission and the delivery of the samples of Phobos to Earth remain of highest priority for Russian scientific community. The next Phobos SR mission named Boomerang was postponed following the ExoMars cooperation, but is considered the next in the line of planetary exploration, suitable for launch around 2022. A

  5. Mars Sample Return Landed with Red Dragon

    NASA Technical Reports Server (NTRS)

    Stoker, Carol R.; Lemke, Lawrence G.

    2013-01-01

    A Mars Sample Return (MSR) mission is the highest priority science mission for the next decade as recommended by the recent Decadal Survey of Planetary Science. However, an affordable program to carry this out has not been defined. This paper describes a study that examined use of emerging commercial capabilities to land the sample return elements, with the goal of reducing mission cost. A team at NASA Ames examined the feasibility of the following scenario for MSR: A Falcon Heavy launcher injects a SpaceX Dragon crew capsule and trunk onto a Trans Mars Injection trajectory. The capsule is modified to carry all the hardware needed to return samples collected on Mars including a Mars Ascent Vehicle (MAV), an Earth Return Vehicle (ERV) and Sample Collection and Storage hardware. The Dragon descends to land on the surface of Mars using SuperSonic Retro Propulsion (SSRP) as described by Braun and Manning [IEEEAC paper 0076, 2005]. Samples are acquired and deliverd to the MAV by a prelanded asset, possibly the proposed 2020 rover. After samples are obtained and stored in the ERV, the MAV launches the sample-containing ERV from the surface of Mars. We examined cases where the ERV is delivered to either low Mars orbit (LMO), C3 = 0 (Mars escape), or an intermediate energy state. The ERV then provides the rest of the energy (delta V) required to perform trans-Earth injection (TEI), cruise, and insertion into a Moon-trailing Earth Orbit (MTEO). A later mission, possibly a crewed Dragon launched by a Falcon Heavy (not part of the current study) retrieves the sample container, packages the sample, and performs a controlled Earth re-entry to prevent Mars materials from accidentally contaminating Earth. The key analysis methods used in the study employed a set of parametric mass estimating relationships (MERs) and standard aerospace analysis software codes modified for the MAV class of launch vehicle to determine the range of performance parameters that produced converged

  6. STS-32 Return to KSC

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Space Shuttle Columbia, returning to KSC after the successful STS-32 mission, is poised atop the Shuttle Carrier Aircraft (SCA) as the duo fly by the Vehicle Assembly Building (VAB) at KSC January 26. Columbia, carrying the Long Duration Exposure Facility (LDEF) in its payload bay, was compleitng a two-day ferry flight from Edwards Air Force Base, California. Landing at the Shuttle Landing Facility occurred a few moments later at 3:30 p.m.

  7. The returning traveler with fever.

    PubMed

    Saxe, S E; Gardner, P

    1992-06-01

    The febrile returning traveler tests a clinician's knowledge of tropical medicine as well as skills in differential diagnosis. A thorough history with special emphasis placed on the patient's travel itinerary and knowledge of the geographic location and incubation times of certain tropical diseases will narrow the diagnostic possibilities. This will allow the clinician to focus the diagnostic work-up and make wise choices of laboratory tests and procedures.

  8. Asteroid Return Mission Feasibility Study

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Gershman, Robert; Landau, Damon; Polk, James; Porter, Chris; Yeomans, Don; Allen, Carlton; Williams, Willie; Asphaug, Erik

    2011-01-01

    This paper describes an investigation into the technological feasibility of finding, characterizing, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the International Space Station (ISS) for scientific investigation, evaluation of its resource potential, determination of its internal structure and other aspects important for planetary defense activities, and to serve as a testbed for human operations in the vicinity of an asteroid. Reasonable projections suggest that several dozen candidates NEAs in the size range of interest (approximately 2-m diameter) will be known before the end of the decade from which a suitable target could be selected. The conceptual mission objective is to return an approximately 10,000-kg asteroid to the ISS in a total flight time of approximately 5 years using a single Evolved Expendable Launch Vehicle. Preliminary calculations indicate that this could be accomplished using a solar electric propulsion (SEP) system with high-power Hall thrusters and a maximum power into the propulsion system of approximately 40 kW. The SEP system would be used to provide all of the post-launch delta V. The asteroid would have an unrestricted Earth return Planetary Protection categorization, and would be curated at the ISS where numerous scientific and resource utilization experiments would be conducted. Asteroid material brought to the ground would be curated at the NASA Johnson Space Center. This preliminary study identified several areas where additional work is required, but no show stoppers were identified for the approach that would return an entire 10,000-kg asteroid to the ISS in a mission that could be launched by the end of this decade.

  9. Economic Returns to Military Service

    DTIC Science & Technology

    1991-07-01

    on subsequent earnings, the short time horizon over which vets could return to school and catchup , and employer discrimination against and societal...the military, drop below those of nonveterans for a brief period after discharge, and then catchup and overtake the earnings of nonveterans thereafter... catchup , and employer discrimination against and societal rejection of Vietnam vets as noted in previous sections of this report. In sum, his studies do not

  10. Challenging Return to Play Decisions

    PubMed Central

    Asplund, Chad A.; O’Connor, Francis G.

    2015-01-01

    Context: Sports medicine providers frequently return athletes to play after sports-related injuries and conditions. Many of these conditions have guidelines or medical evidence to guide the decision-making process. Occasionally, however, sports medicine providers are challenged with complex medical conditions for which there is little evidence-based guidance and physicians are instructed to individualize treatment; included in this group of conditions are exertional heat stroke (EHS), exertional rhabdomyolysis (ER), and exertional collapse associated with sickle cell trait (ECAST). Evidence Acquisition: The MEDLINE (2000-2015) database was searched using the following search terms: exertional heat stroke, exertional rhabdomyolysis, and exertional collapse associated with sickle cell trait. References from consensus statements, review articles, and book chapters were also utilized. Study Design: Clinical review. Level of Evidence: Level 4. Results: These entities are unique in that they may cause organ system damage capable of leading to short- or long-term detriments to physical activity and may not lend to complete recovery, potentially putting the athlete at risk with premature return to play. Conclusion: With a better understanding of the pathophysiology of EHS, ER, and ECAST and the factors associated with recovery, better decisions regarding return to play may be made. PMID:26896216

  11. Tick size and stock returns

    NASA Astrophysics Data System (ADS)

    Onnela, Jukka-Pekka; Töyli, Juuso; Kaski, Kimmo

    2009-02-01

    Tick size is an important aspect of the micro-structural level organization of financial markets. It is the smallest institutionally allowed price increment, has a direct bearing on the bid-ask spread, influences the strategy of trading order placement in electronic markets, affects the price formation mechanism, and appears to be related to the long-term memory of volatility clustering. In this paper we investigate the impact of tick size on stock returns. We start with a simple simulation to demonstrate how continuous returns become distorted after confining the price to a discrete grid governed by the tick size. We then move on to a novel experimental set-up that combines decimalization pilot programs and cross-listed stocks in New York and Toronto. This allows us to observe a set of stocks traded simultaneously under two different ticks while holding all security-specific characteristics fixed. We then study the normality of the return distributions and carry out fits to the chosen distribution models. Our empirical findings are somewhat mixed and in some cases appear to challenge the simulation results.

  12. CRPE: Cesium Return Program Experience FY 1995

    SciTech Connect

    Clements, E.P.

    1995-11-01

    Since 1945, the chemical reprocessing of irradiated nuclear fuels in the Hanford Chemical Separation areas has resulted in the generation of significant volumes of high-level, liquid, radioactive, by-product materials. However, because these materials were recognized to have beneficial uses, their disposal was delayed. To investigate the possibilities, the By-product Utilization Program (BUP) was initiated. The program mission was to develop a means for the application of radioactive-fission products for the benefit of society. Cs capsules were fabricated and distributed to private irradiation facilities for beneficial product sterilization. In June of 1988, a small leak developed in one of the Cs capsules at a private irradiator facility that is located in Decatur, Georgia. This leak prompted DOE to remove these capsules and to re-evaluate the BUP with the irradiator facilities that were currently using Cs capsules. As a result of this evaluation, a recall was issued to require that all remaining Cs capsules be returned to Hanford for safe management and storage pending final capsule disposition. The WHC completed the return of 309 capsules from a private irradiation facility, located in Northglenn, Colorado, to the Hanford Reservation. The DOE is also planning to remove 25 Cs capsules from a small, private irradiator facility located in Lynchburg, Virginia. This small irradiator facility is currently operational and uses the capsules for the underwater irradiation of wood-flooring products. This report discusses transportation-related activities that WHC has researched, developed, implemented, and is currently managing to ensure the safe and efficient movement of Cs-137 back to the Hanford Reservation.

  13. Maternity Leave: Tips for Returning to Work

    MedlinePlus

    ... telecommuting or working part time. Prepare to continue breast-feeding. If you plan to breast-feed after returning ... or nearby child care, consider the logistics of breast-feeding your baby during the workday. Set a return- ...

  14. Returning to sports after a back injury

    MedlinePlus

    ... medlineplus.gov/ency/patientinstructions/000518.htm Returning to sports after a back injury To use the sharing ... Back pain - returning to sports Which Type of Sport is Best? In deciding when and if to ...

  15. 5 CFR 1650.5 - Returned funds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Returned funds. 1650.5 Section 1650.5 Administrative Personnel FEDERAL RETIREMENT THRIFT INVESTMENT BOARD METHODS OF WITHDRAWING FUNDS FROM THE THRIFT SAVINGS PLAN General § 1650.5 Returned funds. If a withdrawal is returned as undeliverable, the TSP...

  16. Heterogeneity in Schooling Rates of Return

    ERIC Educational Resources Information Center

    Henderson, Daniel J.; Polachek, Solomon W.; Wang, Le

    2011-01-01

    This paper relaxes the assumption of homogeneous rates of return to schooling by employing nonparametric kernel regression. This approach allows us to examine the differences in rates of return to education both across and within groups. Similar to previous studies we find that on average blacks have higher returns to education than whites,…

  17. Mars 2005 Sample Return Workshop

    NASA Technical Reports Server (NTRS)

    Gulick, V. C. (Editor)

    1997-01-01

    Convened at the request of Dr. Jurgen Rahe of the NASA Office of Space Science, the purpose of this workshop was to reexamine the science issues that will determine how an optimum sample return mission would be carried out in 2005 given the new context that has emerged for Mars exploration since the last such workshop was held (in 1987). The results and summary of discussion that took place at the meeting are contained in this volume. The community was invited to participate in the preparation of the final written report by browsing through the agenda and reading the text and viewgraphs provided by workshop participants and submitting comments for that section.

  18. Return to Flight Task Group

    NASA Technical Reports Server (NTRS)

    2005-01-01

    It has been 29 months since Columbia was lost over East Texas in February 2003. Seven months after the accident, the Columbia Accident Investigation Board (CAIB) released the first volume of its final report, citing a variety of technical, managerial, and cultural issues within NASA and the Space Shuttle Program. To their credit, NASA offered few excuses, embraced the report, and set about correcting the deficiencies noted by the accident board. Of the 29 recommendations issued by the CAIB, 15 were deemed critical enough that the accident board believed they should be implemented prior to returning the Space Shuttle to flight. Some of these recommendations were relatively easy, most were straightforward, a few bordered on the impossible, and others were largely overcome by events, particularly the decision by the President to retire the Space Shuttle by 2010. The Return to Flight Task Group (RTF TG, or simply, the Task Group) was chartered by the NASA Administrator in July 2003 to provide an independent assessment of the implementation of the 15 CAIB return-to-flight recommendations. An important observation must be stated up-front: neither the CAIB nor the RTF TG believes that all risk can be eliminated from Space Shuttle operations; nor do we believe that the Space Shuttle is inherently unsafe. What the CAIB and RTF TG do believe, however, is that NASA and the American public need to understand the risks associated with space travel, and that NASA must make every reasonable effort to minimize such risk. Since the release of the CAIB report, NASA and the Space Shuttle Program expended enormous effort and resources toward correcting the causes of the accident and preparing to fly again. Relative to the 15 specific recommendations that the CAIB indicated should be implemented prior to returning to flight, NASA has met or exceeded most of them the Task Group believes that NASA met the intent of the CAIB for 12 of these recommendations. The remaining three

  19. Hematospermia in a returned traveler

    PubMed Central

    Lang, Raynell; Minion, Jessica; Wong, Alexander

    2017-01-01

    Hematospermia is a common complaint among patients seen in outpatient urology clinics. The differential diagnosis is broad and includes inflammatory, infectious, neoplastic, structural, systemic, and traumatic causes. The most common infectious causes are uropathogens and sexually transmitted infections. However, with increasing global travel, physicians must maintain a high clinical suspicion for pathogens not endemic to their region, including Echinococcus, Mycobacterium tuberculosis, and Schistosoma.1 We present a case of hematospermia in a traveler returning from Eastern Africa with exposure to Lake Malawi. The patient’s microscopic analysis of semen was positive for Schistosoma haematobium, revealing a rare presentation of S. haematobium infection. PMID:28163813

  20. Returning individual research results for genome sequences of pancreatic cancer

    PubMed Central

    2014-01-01

    Background Disclosure of individual results to participants in genomic research is a complex and contentious issue. There are many existing commentaries and opinion pieces on the topic, but little empirical data concerning actual cases describing how individual results have been returned. Thus, the real life risks and benefits of disclosing individual research results to participants are rarely if ever presented as part of this debate. Methods The Australian Pancreatic Cancer Genome Initiative (APGI) is an Australian contribution to the International Cancer Genome Consortium (ICGC), that involves prospective sequencing of tumor and normal genomes of study participants with pancreatic cancer in Australia. We present three examples that illustrate different facets of how research results may arise, and how they may be returned to individuals within an ethically defensible and clinically practical framework. This framework includes the necessary elements identified by others including consent, determination of the significance of results and which to return, delineation of the responsibility for communication and the clinical pathway for managing the consequences of returning results. Results Of 285 recruited patients, we returned results to a total of 25 with no adverse events to date. These included four that were classified as medically actionable, nine as clinically significant and eight that were returned at the request of the treating clinician. Case studies presented depict instances where research results impacted on cancer susceptibility, current treatment and diagnosis, and illustrate key practical challenges of developing an effective framework. Conclusions We suggest that return of individual results is both feasible and ethically defensible but only within the context of a robust framework that involves a close relationship between researchers and clinicians. PMID:24963353

  1. Submicrosecond risetimes in lightning return-stroke fields

    NASA Technical Reports Server (NTRS)

    Weidman, C. D.; Krider, E. P.

    1980-01-01

    Measurements of lightning electric field, E, and dE/dt signatures have been made near Tampa Bay, Florida, under conditions where the lightning locations were known and where the results were not significantly affected by the response time of the measuring system or groundwave propagation. The fast transitions found on the initial portion of return-stroke fields have 10-90% risetimes ranging from 40 to 200 nsec, with a mean of 90 nsec. The maximum field derivatives during return strokes range from 5 to 75 V/m per microsec with a mean of 29 V/m per microsec when normalized to a distance of 100 km. These field risetime and derivative values suggest that return-stroke currents contain large, submicrosecond components, and this in turn suggests that it may be necessary to reevaluate the possible effects of lightning and the performance of lightning-protection devices in many situations.

  2. Returning to work while breastfeeding.

    PubMed

    Biagioli, Frances

    2003-12-01

    Mothers who work outside the home initiate breastfeeding at the same rate as mothers who stay at home. However, the breastfeeding continuance rate declines sharply in mothers who return to work. While the work environment may be less than ideal for the breastfeeding mother, obstacles can be overcome. Available breast pump types include manual pumps, battery-powered pumps, electric diaphragm pumps, electric piston pumps, and hospital-grade electric piston pumps. Electric piston pumps may be the most suitable type for mothers who work outside the home for more than 20 hours per week; however, when a mother is highly motivated, any pump type can be successful in any situation. Conservative estimates suggest that breast milk can be stored at room temperature for eight hours, refrigerated for up to eight days, and frozen for many months. A breastfeeding plan can help the working mother anticipate logistic problems and devise a practical pumping schedule. A mother's milk production usually is well established by the time her infant is four weeks old; it is best to delay a return to work until at least that time, and longer if possible.

  3. The dynamics of health and return migration.

    PubMed

    Davies, Anita A; Borland, Rosilyne M; Blake, Carolyn; West, Haley E

    2011-06-01

    The increasing importance and complexity of migration globally also implies a global increase in return migration, and thus an increased interest in the health of returning migrants. The health of returning migrants is impacted by the cumulative exposure to social determinants and risk factors of health during the migration process, during the return movement, and following return. Circular migration often occurs among the diaspora, which can result in the transfer of knowledge and skills that contribute to development, including health system strengthening. Migrants with dual nationality often return to countries with better health services than their country of origin when they are sick and can not get care at home. To maintain and improve the health of returning migrants, multi-sectoral policies at global and national levels should facilitate access to appropriate and equitable health services, social services, and continuity of care across and within borders.

  4. THE RETURN OF THE ANDROMEDIDS METEOR SHOWER

    SciTech Connect

    Wiegert, Paul A.; Brown, Peter G.; Weryk, Robert J.; Wong, Daniel K.

    2013-03-15

    The Andromedid meteor shower underwent spectacular outbursts in 1872 and 1885, producing thousands of visual meteors per hour and described as ''stars fell like rain'' in Chinese records of the time. The shower originates from comet 3D/Biela whose disintegration in the mid-1800's is linked to the outbursts, but the shower has been weak or absent since the late 19th century. This shower returned in 2011 December with a zenithal hourly rate of approximately 50, the strongest return in over a hundred years. Some 122 probable Andromedid orbits were detected by the Canadian Meteor Orbit Radar while one possible brighter Andromedid member was detected by the Southern Ontario Meteor Network and several single station possible Andromedids by the Canadian Automated Meteor Observatory. The shower outburst occurred during 2011 December 3-5. The radiant at R.A. +18 Degree-Sign and decl. +56 Degree-Sign is typical of the ''classical'' Andromedids of the early 1800s, whose radiant was actually in Cassiopeia. Numerical simulations of the shower were necessary to identify it with the Andromedids, as the observed radiant differs markedly from the current radiant associated with that shower. The shower's orbital elements indicate that the material involved was released before 3D/Biela's breakup prior to 1846. The observed shower in 2011 had a slow geocentric speed (V{sub G} = 16 km s{sup -1}) and was comprised of small particles: the mean measured mass from the radar is {approx}5 Multiplication-Sign 10{sup -7} kg, corresponding to radii of 0.5 mm at a bulk density of 1000 kg m{sup -3}. Numerical simulations of the parent comet indicate that the meteoroids of the 2011 return of the Andromedids shower were primarily ejected during 3D/Biela's 1649 perihelion passage. The orbital characteristics, radiant, and timing as well as the absence of large particles in the streamlet are all broadly consistent with simulations. However, simulations of the 1649 perihelion passage necessitate going

  5. Risk analysis of earth return options for the Mars rover/sample return mission

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Four options for return of a Mars surface sample to Earth were studied to estimate the risk of mission failure and the risk of a sample container breach that might result in the release of Martian life forms, should such exist, in the Earth's biosphere. The probabilities calculated refer only to the time period from the last midcourse correction burn to possession of the sample on Earth. Two extreme views characterize this subject. In one view, there is no life on Mars, therefore there is no significant risk and no serious effort is required to deal with back contamination. In the other view, public safety overrides any desire to return Martian samples, and any risk of damaging contamination greater than zero is unacceptable. Zero risk requires great expense to achieve and may prevent the mission as currently envisioned from taking place. The major conclusion is that risk of sample container breach can be reduced to a very low number within the framework of the mission as now envisioned, but significant expense and effort, above that currently planned is needed. There are benefits to the public that warrant some risk. Martian life, if it exists, will be a major discovery. If it does not, there is no risk.

  6. Potential of space-borne GNSS reflectometry to constrain simulations of the ocean circulation. A case study for the South African current system

    NASA Astrophysics Data System (ADS)

    Saynisch, Jan; Semmling, Maximilian; Wickert, Jens; Thomas, Maik

    2015-11-01

    The Agulhas current system transports warm and salty water masses from the Indian Ocean into the Southern Ocean and into the Atlantic. The transports impact past, present, and future climate on local and global scales. The size and variability, however, of the respective transports are still much debated. In this study, an idealized model based twin experiment is used to study whether sea surface height (SSH) anomalies estimated from reflected signals of the Global Navigation Satellite System reflectometry (GNSS-R) can be used to determine the internal water mass properties and transports of the Agulhas region. A space-borne GNSS-R detector on the International Space Station (ISS) is assumed and simulated. The detector is able to observe daily SSH fields with a spatial resolution of 1-5∘. Depending on reflection geometry, the precision of a single SSH observation is estimated to reach 3 cm (20 cm) when the carrier phase (code delay) information of the reflected GNSS signal is used. The average precision over the Agulhas region is 7 cm (42 cm). The proposed GNSS-R measurements surpass the radar-based satellite altimetry missions in temporal and spatial resolution but are less precise. Using the estimated GNSS-R characteristics, measurements of SSH are generated by sampling a regional nested general circulation model of the South African oceans. The artificial observations are subsequently assimilated with a 4DVAR adjoint data assimilation method into the same ocean model but with a different initial state and forcing. The assimilated and the original, i.e., the sampled model state, are compared to systematically identify improvements and degradations in the model variables that arise due to the assimilation of GNSS-R based SSH observations. We show that SSH and the independent, i.e., not assimilated model variables velocity, temperature, and salinity improve by the assimilation of GNSS-R based SSH observations. After the assimilation of 90 days of SSH observations

  7. Mars Sample Return mission utilizing in-situ propellant production

    NASA Technical Reports Server (NTRS)

    Zubrin, Robert; Price, Steve

    1995-01-01

    This report presents the results of a study examining the potential of in-situ propellant production (ISPP) on Mars to aid in achieving a low cost Mars Sample Return (MSR) mission. Two versions of such a mission were examined: a baseline version employing a dual string spacecraft, and a light weight version employing single string architecture with selective redundancy. Both systems employed light weight avionics currently being developed by Lockheed Martin, Jet Propulsion Lab and elsewhere in the aerospace community, both used a new concept for a simple, light weight parachuteless sample return capsule, both used a slightly modified version of the Mars Surveyor lander currently under development at Lockheed Martin for flight in 1998, and both used a combination of the Sabatier-electrolysis and reverse water gas shift ISPP systems to produce methane/oxygen propellant on Mars by combining a small quantity of imported hydrogen with the Martian CO2 atmosphere. It was found that the baseline mission could be launched on a Delta 7925 and return a 0.5 kg sample with 82 percent mission launch margin;over and beyond subsystem allocated contingency masses . The lightweight version could be launched on a Mid-Lite vehicle and return a 0.25 kg sample with 11 percent launch margin, over and above subsystem contingency mass allocations.

  8. Melioidosis in a returning traveller

    PubMed Central

    Ismail, Alaa; Buckley, Adam; Dubrey, Simon William

    2013-01-01

    A 66-year-old man returned to the UK from Thailand with a 2-week history of new confusion, hallucinations, fever with rigours and productive cough. He had not responded to (unspecified) antibiotic treatment in Thailand. On examination he was afebrile, with an abbreviated mental test score of 8/10 and no other findings on systemic examination. He was treated with ceftriaxone in response to discovery of a Gram-negative organism in blood. This was converted to meropenem on the clinical suspicion of our microbiologist, on the basis of a history of contact with surface water in the Far East. A blood culture subsequently confirmed Burkholderia pseudomallei. His condition remained stable for approximately 4 days, but then deteriorated over the course of the next 2 weeks with pneumonia and subsequent formation of disseminated abscesses. Treatment was withdrawn as his condition deteriorated to the point at which survival was deemed impossible and he subsequently died. PMID:23605844

  9. Partial Return Yoke for MICE

    SciTech Connect

    Witte H.; Plate, S

    2013-05-03

    The international Muon Ionization Cooling Experiment (MICE) is a large scale experiment which is presently assembled at the Rutherford Appleton Laboratory in Didcot, UK. The purpose of MICE is to demonstrate the concept of ionization cooling experimentally. Ionization cooling is an important accelerator concept which will be essential for future HEP experiments such as a potential Muon Collider or a Neutrino Factory. The MICE experiment will house up to 18 superconducting solenoids, all of which produce a substantial amount of magnetic flux. Recently it was realized that this magnetic flux leads to a considerable stray magnetic field in the MICE hall. This is a concern as technical equipment in the MICE hall may may be compromised by this. In July 2012 a concept called partial return yoke was presented to the MICE community, which reduces the stray field in the MICE hall to a safe level. This report summarizes the general concept, engineering considerations and the expected shielding performance.

  10. Sample Return Enabled by a Crewed Presence in Cislunar or Cismartian Space: Farther Reach, Better Science

    NASA Astrophysics Data System (ADS)

    Lewis, R.; Niles, P.; Fries, M.; McCubbin, F.; Archer, D.; Bleacher, J.; Boyce, J.; Cohen, B.; Evans, C.; Graff, T.; Gruener, J.; Lawrence, S.; Lupisella, M.; Ming, D.; Needham, D.; Young, K.

    2017-02-01

    Human presence in/on lunar and Mars space/surfaces provides a unique opportunity to utilize robust spacecraft infrastructure as well as the capabilities of humans to fundamentally improve sample return well beyond current capabilities.

  11. Understanding the multifractality in portfolio excess returns

    NASA Astrophysics Data System (ADS)

    Chen, Cheng; Wang, Yudong

    2017-01-01

    The multifractality in stock returns have been investigated extensively. However, whether the autocorrelations in portfolio returns are multifractal have not been considered in the literature. In this paper, we detect multifractal behavior of returns of portfolios constructed based on two popular trading rules, size and book-to-market (BM) ratio. Using the multifractal detrended fluctuation analysis, we find that the portfolio returns are significantly multifractal and the multifractality is mainly attributed to long-range dependence. We also investigate the multifractal cross-correlation between portfolio return and market average return using the detrended cross-correlation analysis. Our results show that the cross-correlations of small fluctuations are persistent, while those of large fluctuations are anti-persistent.

  12. Return to Work After Diskogenic Fusion in Workers' Compensation Subjects.

    PubMed

    Anderson, Joshua T; Haas, Arnold R; Percy, Rick; Woods, Stephen T; Ahn, Uri M; Ahn, Nicholas U

    2015-12-01

    Lumbar fusion for degenerative disk disease (DDD) is associated with variable clinical outcomes. Patients with workers' compensation claims often have worse fusion outcomes than the general population. Few studies have evaluated the risk factors for poor outcomes within this clinically distinct population. The goal of this study was to identify preoperative predictors of return to work status after fusion for DDD in a workers' compensation setting. The authors used International Classification of Diseases, Ninth Revision (ICD-9), diagnosis and Current Procedural Terminology (CPT) procedural codes to identify 1037 subjects from the Ohio Bureau of Workers' Compensation database who underwent fusion for DDD between 1993 and 2013. Of these subjects, 23.2% (n=241) made a sustained return to work within 2 years after fusion. To identify preoperative predictors of postoperative return to work status, the authors used multivariate logistic regression analysis, adjusting for many important covariates. These included prolonged time out of work (P<.001; odds ratio [OR], 0.24), psychiatric history (P<.001; OR, 0.14), prolonged use of opioid analgesics (P<.001; OR, 0.46), male sex (P=.014; OR, 0.65), and legal representation (P=.042; OR, 0.67). The return to work rates associated with these risk factors were 10.4%, 2.0%, 11.9%, 21.1%, and 20.7%, respectively. Of the study subjects, 76.8% (n=796) did not return to work and had considerably worse postoperative outcomes, highlighted by chronic opioid dependence and high rates of failed back syndrome, additional surgery, and new psychiatric comorbidity. The low return to work rates and other generally poor outcomes reported in this study may indicate a more limited role for lumbar fusion among patients with DDD who have workers' compensation claims. More studies are needed to determine whether fusion for DDD can improve function and quality of life in these patients.

  13. 76 FR 17521 - Specified Tax Return Preparers Required To File Individual Income Tax Returns Using Magnetic Media

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-30

    ... File Individual Income Tax Returns Using Magnetic Media AGENCY: Internal Revenue Service (IRS... for ``specified tax return preparers'' to file individual income tax returns using magnetic media... individual income tax returns using magnetic media (electronically). Section 17 of the Worker,...

  14. Bulgarian Turkish emigration and return.

    PubMed

    Vasileva, D

    1992-01-01

    The main factors which determined the 1989 migration of Turks in Bulgaria back to Turkey are discussed. Background history is provided. After World War I, Turks in bulgaria comprised 10% of the total population. Bulgarian policy had been, up to the 1980s to send Rumelian Turks back, but the policy after 1980 was one of a national revival process to integrate Turks into the developed socialist society. Muslim traditions, customs, and Turkish language were interfered with. International disfavor resulted. In May 1989, the Communist Party declared, in an effort to show democratic ideals, open borders. Thus began the new emigration wave. 369,839 people fled to the Turkish border. 43% of the 9.47 ethnic Turks in bulgaria went to Turkey within 4 months. The numbers decreased in November, and soon after the communist regime ended. New laws were adopted allowing Turks to assume their original Turkish names. The huge migration was clearly political, and as such, the emigrant Turks should be determined as refugees and asylum seekers. The provocation of ethnic Turks was used by the communist regime to solve potential social conflicts. Not only did Turks flee to escape from violence or for religious, cultural, and moral reasons but also due to free market initiatives begun in Turkey in the early 1980s which improved Turkish quality of life. Food and consumer goods were cheaper and economic advantages were perceived. Emigrants were primarily peasants with lower levels of education, professional qualifications, and labor skills. 154,937 (42%) returned to bulgaria and 58% stayed in Turkey to comprise 25% of the former Turkish population. During this period, tensions between countries was high.l Bulgarians actively encouraged emigration and Turkey welcomed it. The emigrants to Turkey were seen as foreigners (muhacir or gocmen) but were received with good will and were readily accepted into menial positions. Emigrants were confronted with political, linguistic, and cultural

  15. 7 CFR 356.8 - Return procedure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Return procedure. 356.8 Section 356.8 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FORFEITURE PROCEDURES § 356.8 Return procedure. If, at the conclusion...

  16. 26 CFR 50.7 - Returns.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) REGULATIONS RELATING TO THE TAX IMPOSED WITH RESPECT TO CERTAIN HYDRAULIC MINING § 50.7 Returns. (a) Form of... on which hydraulic mining operations began and ended during the taxable year for which the return is made; (7) The number of cubic yards mined by the hydraulic process at the mine during the taxable...

  17. 26 CFR 50.7 - Returns.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) REGULATIONS RELATING TO THE TAX IMPOSED WITH RESPECT TO CERTAIN HYDRAULIC MINING § 50.7 Returns. (a) Form of... on which hydraulic mining operations began and ended during the taxable year for which the return is made; (7) The number of cubic yards mined by the hydraulic process at the mine during the taxable...

  18. 26 CFR 50.7 - Returns.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) REGULATIONS RELATING TO THE TAX IMPOSED WITH RESPECT TO CERTAIN HYDRAULIC MINING § 50.7 Returns. (a) Form of... on which hydraulic mining operations began and ended during the taxable year for which the return is made; (7) The number of cubic yards mined by the hydraulic process at the mine during the taxable...

  19. 26 CFR 50.7 - Returns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) REGULATIONS RELATING TO THE TAX IMPOSED WITH RESPECT TO CERTAIN HYDRAULIC MINING § 50.7 Returns. (a) Form of... on which hydraulic mining operations began and ended during the taxable year for which the return is made; (7) The number of cubic yards mined by the hydraulic process at the mine during the taxable...

  20. 26 CFR 50.7 - Returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) REGULATIONS RELATING TO THE TAX IMPOSED WITH RESPECT TO CERTAIN HYDRAULIC MINING § 50.7 Returns. (a) Form of... on which hydraulic mining operations began and ended during the taxable year for which the return is made; (7) The number of cubic yards mined by the hydraulic process at the mine during the taxable...

  1. Aggregate Unemployment Decreases Individual Returns to Education

    ERIC Educational Resources Information Center

    Ammermueller, Andreas; Kuckulenz, Anja; Zwick, Thomas

    2009-01-01

    Aggregate unemployment may affect individual returns to education through qualification-specific responses in participation and wage bargaining. This paper shows that an increase in regional unemployment by 1% decreases returns to education by 0.005 percentage points. This implies that higher skilled employees are better sheltered from labour…

  2. The Returns to Quality in Graduate Education

    ERIC Educational Resources Information Center

    Stevenson, Adam

    2016-01-01

    This paper estimates the monetary return to quality in US graduate education, controlling for cognitive ability and self-selection across award level, program quality, and field-of-study. In most program types, I cannot reject the hypothesis of no returns to either degree completion or program quality. Important exceptions include master's…

  3. 46 CFR 308.514 - Return premium.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Return premium. 308.514 Section 308.514 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance § 308.514 Return premium. No premium will...

  4. 27 CFR 41.112 - Tax return.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2012-04-01 2011-04-01 true Tax return. 41.112 Section 41.112 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... States Deferred Payment of Tax in Puerto Rico on Tobacco Products § 41.112 Tax return. The...

  5. 27 CFR 41.112 - Tax return.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2013-04-01 2013-04-01 false Tax return. 41.112 Section 41.112 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... States Deferred Payment of Tax in Puerto Rico on Tobacco Products § 41.112 Tax return. The...

  6. 27 CFR 41.112 - Tax return.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Tax return. 41.112 Section 41.112 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... States Deferred Payment of Tax in Puerto Rico on Tobacco Products § 41.112 Tax return. The...

  7. 27 CFR 41.112 - Tax return.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2011-04-01 2011-04-01 false Tax return. 41.112 Section 41.112 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... States Deferred Payment of Tax in Puerto Rico on Tobacco Products § 41.112 Tax return. The...

  8. 27 CFR 41.112 - Tax return.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2014-04-01 2014-04-01 false Tax return. 41.112 Section 41.112 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... States Deferred Payment of Tax in Puerto Rico on Tobacco Products § 41.112 Tax return. The...

  9. 21 CFR 203.23 - Returns.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., or charitable institution documents the return by filling out a credit memo specifying: (1) The name..., health care entity, or charitable institution forwards a copy of each credit memo to the manufacturer and retains a copy of each credit memo for its records; (c) Any drugs returned to a manufacturer or...

  10. 21 CFR 203.23 - Returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., or charitable institution documents the return by filling out a credit memo specifying: (1) The name..., health care entity, or charitable institution forwards a copy of each credit memo to the manufacturer and retains a copy of each credit memo for its records; (c) Any drugs returned to a manufacturer or...

  11. 21 CFR 203.23 - Returns.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., or charitable institution documents the return by filling out a credit memo specifying: (1) The name..., health care entity, or charitable institution forwards a copy of each credit memo to the manufacturer and retains a copy of each credit memo for its records; (c) Any drugs returned to a manufacturer or...

  12. 21 CFR 203.23 - Returns.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., or charitable institution documents the return by filling out a credit memo specifying: (1) The name..., health care entity, or charitable institution forwards a copy of each credit memo to the manufacturer and retains a copy of each credit memo for its records; (c) Any drugs returned to a manufacturer or...

  13. 21 CFR 203.23 - Returns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., or charitable institution documents the return by filling out a credit memo specifying: (1) The name..., health care entity, or charitable institution forwards a copy of each credit memo to the manufacturer and retains a copy of each credit memo for its records; (c) Any drugs returned to a manufacturer or...

  14. Returned Solar Max hardware degradation study results

    NASA Technical Reports Server (NTRS)

    Triolo, Jack J.; Ousley, Gilbert W.

    1989-01-01

    The Solar Maximum Repair Mission returned with the replaced hardware that had been in low Earth orbit for over four years. The materials of this returned hardware gave the aerospace community an opportunity to study the realtime effects of atomic oxygen, solar radiation, impact particles, charged particle radiation, and molecular contamination. The results of these studies are summarized.

  15. 46 CFR 308.514 - Return premium.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Return premium. 308.514 Section 308.514 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance § 308.514 Return premium. No premium will...

  16. 46 CFR 308.514 - Return premium.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Return premium. 308.514 Section 308.514 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance § 308.514 Return premium. No premium will...

  17. 46 CFR 308.514 - Return premium.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Return premium. 308.514 Section 308.514 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Open Policy War Risk Cargo Insurance § 308.514 Return premium. No premium will...

  18. 46 CFR 308.514 - Return premium.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Return premium. 308.514 Section 308.514 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance § 308.514 Return premium. No premium will...

  19. 12 CFR 210.12 - Return of cash items and handling of returned checks.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Return of cash items and handling of returned checks. 210.12 Section 210.12 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL... FEDWIRE (REGULATION J) Collection of Checks and Other Items By Federal Reserve Banks § 210.12 Return...

  20. 26 CFR 1.6013-2 - Joint return after filing separate return.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... of the excess. (ii) If any part of such excess is attributable to fraud with intent to evade tax at... (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Tax Returns Or Statements § 1.6013-2 Joint return after... separate return of either spouse are to be taken into account in determining the extent to which the...

  1. Rossby Rip Currents

    NASA Astrophysics Data System (ADS)

    Marshall, D. P.; Vogel, B.; Zhai, X.

    2014-12-01

    Oceanic Rossby waves and eddies flux energy and fluid westward, the latter through the Stokes drift or bolus transport. While the wave energy is largely dissipated at the western boundary, mass conservation requires that the fluid be returned offshore through Rossby rip currents. The form and magnitude of these rip currents are investigated through linear Rossby wave theory, a nonlinear numerical model, and analysis of sea surface height satellite observations. The net eastward volume transport by Rossby rip currents over the global ocean is estimated to be of order 10 Sv. In an eddying ocean, both the westward Stokes drift and eastward rip currents assume the form of banded quasi-zonal jets, albeit for reasons unrelated to the rip currents themselves. A mismatch between the vertical structures of the eddy energy and the Rossby rip currents will also be discussed.

  2. Characterization of avalanche photodiodes for lidar atmospheric return signal detectors

    NASA Technical Reports Server (NTRS)

    Antill, C. W., Jr.; Holloway, R. M.

    1988-01-01

    Results are presented from tests to characterize noise, dark current, overload, and gain versus bias, relationships of ten avalanche photodiodes. The advantages of avalanche photodiodes over photomultiplier tubes for given laser wavelengths and return signal amplitudes are outlined. The relationship between responsivity and temperature and dark current and temperature are examined. Also, measurements of the noise equivalent power, the excess noise factor, and linearity are given. The advantages of using avalanche photodiodes in the Lidar Atmospheric Sensing Experiment and the Lidar In-Space Technology Experiment are discussed.

  3. What stock market returns to expect for the future?

    PubMed

    Diamond, P A

    2000-01-01

    In evaluating proposals for reforming Social Security that involve stock investments, the Office of the Chief Actuary (OCACT) has generally used a 7.0 percent real return for stocks. The 1994-96 Advisory Council specified that OCACT should use that return in making its 75-year projections of investment-based reform proposals. The assumed ultimate real return on Treasury bonds of 3.0 percent implies a long-run equity premium of 4.0 percent. There are two equity-premium concepts: the realized equity premium, which is measured by the actual rates of return; and the required equity premium, which investors expect to receive for being willing to hold available stocks and bonds. Over the past two centuries, the realized premium was 3.5 percent on average, but 5.2 percent for 1926 to 1998. Some critics argue that the 7.0 percent projected stock returns are too high. They base their arguments on recent developments in the capital market, the current high value of the stock market, and the expectation of slower economic growth. Increased use of mutual funds and the decline in their costs suggest a lower required premium, as does the rising fraction of the American public investing in stocks. The size of the decrease is limited, however, because the largest cost savings do not apply to the very wealthy and to large institutional investors, who hold a much larger share of the stock market's total value than do new investors. These trends suggest a lower equity premium for projections than the 5.2 percent of the past 75 years. Also, a declining required premium is likely to imply a temporary increase in the realized premium because a rising willingness to hold stocks tends to increase their price. Therefore, it would be a mistake during a transition period to extrapolate what may be a temporarily high realized return. In the standard (Solow) economic growth model, an assumption of slower long-run growth lowers the marginal product of capital if the savings rate is constant

  4. Mars Orbiter Sample Return Power Design

    NASA Technical Reports Server (NTRS)

    Mardesich, N.; Dawson, S.

    2005-01-01

    Mars has greatly intrigued scientists and the general public for many years because, of all the planets, its environment is most like Earth's. Many scientists believe that Mars once had running water, although surface water is gone today. The planet is very cold with a very thin atmosphere consisting mainly of CO2. Mariner 4, 6, and 7 explored the planet in flybys in the 1960s and by the orbiting Mariner 9 in 1971. NASA then mounted the ambitious Viking mission, which launched two orbiters and two landers to the planet in 1975. The landers found ambiguous evidence of life. Mars Pathfinder landed on the planet on July 4, 1997, delivering a mobile robot rover that demonstrated exploration of the local surface environment. Mars Global Surveyor is creating a highest-resolution map of the planet's surface. These prior and current missions to Mars have paved the way for a complex Mars Sample Return mission planned for 2003 and 2005. Returning surface samples from Mars will necessitate retrieval of material from Mars orbit. Sample mass and orbit are restricted to the launch capability of the Mars Ascent Vehicle. A small sample canister having a mass less than 4 kg and diameter of less than 16 cm will spend from three to seven years in a 600 km orbit waiting for retrieval by a second spacecraft consisting of an orbiter equipped with a sample canister retrieval system, and a Earth Entry Vehicle. To allow rapid detection of the on-orbit canister, rendezvous, and collection of the samples, the canister will have a tracking beacon powered by a surface mounted solar array. The canister must communicate using RF transmission with the recovery vehicle that will be coming in 2006 or 2009 to retrieve the canister. This paper considers the aspect and conclusion that went into the design of the power system that achieves the maximum power with the minimum risk. The power output for the spherical orbiting canister was modeled and plotted in various views of the orbit by the Satellite

  5. Preventive letter: doubling the return rate after gestational diabetes mellitus.

    PubMed

    Olmos, Pablo R; Borzone, Gisella R; Berkowitz, Loni; Mertens, Nicolás; Busso, Dolores; Santos, José L; Poblete, José A; Vera, Claudio; Belmar, Cristián; Goldenberg, Denisse; Samith, Bárbara; Acosta, Ana M; Escalona, Manuel

    2015-05-01

    To measure the impact of a "Preventive Letter" designed to encourage the return of gestational diabetes mellitus (GDM) mothers to follow up visit after delivery, in the context of a worldwide concern about low return rates after delivery of these patients. Mothers with GDM require medical evaluation and an oral glucose tolerance test (OGTT) 6 weeks after delivery, in order to: [a] confirm remission of GDM and [b] provide advice on the prevention of type 2 diabetes. In the year 2003 we developed a "Preventive Letter", containing three aspects: [a] current treatment, [b] suggested management during labor, and [c] a stapled laboratory order for OGTT to be performed 6 weeks after delivery. The return rate after delivery was assessed in two groups of GDM mothers: [a] "Without Preventive Letter" (n = 253), and "With Preventive Letter" (n = 215). Both groups, similar with respect to age (33.0 ± 5.4 and 32.3 ± 4.9 years respectively, p = 0.166) and education time (14.9 ± 1.8 and 15.0 ± 1.8 years respectively, p = 0.494), showed a significant difference in the 1-year return rate after delivery, as assessed by the Kaplan-Meier test: 32.0 % for the group "Without Preventive Letter", and 76.0 % for the group "With Preventive Letter" (p < 0.001). The 1-year return rate after delivery of GDM mothers was 2.4 times higher in the group "With Preventive Letter" than in the group without it. We believe that this low-cost approach could be useful in other institutions caring for pregnant women with diabetes.

  6. Return to work after knee replacement: a qualitative study of patient experiences

    PubMed Central

    Bardgett, Michelle; Lally, Joanne; Malviya, Ajay; Deehan, David

    2016-01-01

    Objective An increasing number of patients in the working population are undergoing total knee replacement (TKR) for end-stage osteoarthritis. The timing and success of return to work is becoming increasingly important for this group of patients with social and economic implications for patients, employers and society. There is limited understanding of the patient variables that determine the ability to return to work. Our objective was (from the patient's perspective) to gain an insight into the factors influencing return to work following knee replacement. Setting and participants This qualitative study was undertaken in a secondary-care setting in a large teaching hospital in the north of England. Semistructured interviews were carried out with 10 patients regarding their experiences of returning to work following TKR. Outcomes Interviews were transcribed and analysed using a qualitative thematic approach to identify the factors influencing return to work from the patient's perspective. Results Three themes were identified that influenced the process of return to work, from the patient's perspective. These were delays in surgical intervention, limited and often inconsistent advice from healthcare professionals regarding return to work, and finally the absence of rehabilitation to optimise patient's recovery and facilitate return to work. Conclusions There is currently no consistent process to optimise return to work for patients of working age after TKR. The impact of delayed surgical intervention, limited advice regarding return to work, and a lack of work-focused rehabilitation, all contribute to potential delays in successful return to work. There is a need to change the focus of healthcare provision for this cohort of patients, and provide a tailored healthcare intervention to optimise patient outcomes. PMID:26832426

  7. Integrating public perspectives in sample return planning.

    PubMed

    Race, M S; MacGregor, D G

    2000-01-01

    Planning for extraterrestrial sample returns--whether from Mars or other solar system bodies--must be done in a way that integrates planetary protection concerns with the usual mission technical and scientific considerations. Understanding and addressing legitimate societal concerns about the possible risks of sample return will be a critical part of the public decision making process ahead. This paper presents the results of two studies, one with lay audiences, the other with expert microbiologists designed to gather information on attitudes and concerns about sample return risks and planetary protection. Focus group interviews with lay subjects, using generic information about Mars sample return and a preliminary environmental impact assessment, were designed to obtain an indication of how the factual content is perceived and understood by the public. A research survey of microbiologists gathered information on experts' views and attitudes about sample return, risk management approaches and space exploration risks. These findings, combined with earlier research results on risk perception, will be useful in identifying levels of concern and potential conflicts in understanding between experts and the public about sample return risks. The information will be helpful in guiding development of the environmental impact statement and also has applicability to proposals for sample return from other solar system bodies where scientific uncertainty about extraterrestrial life may persist at the time of mission planning.

  8. Reliability, return periods, and risk under nonstationarity

    NASA Astrophysics Data System (ADS)

    Read, Laura K.; Vogel, Richard M.

    2015-08-01

    Water resources design has widely used the average return period as a concept to inform management and communication of the risk of experiencing an exceedance event within a planning horizon. Even though nonstationarity is often apparent, in practice hydrologic design often mistakenly assumes that the probability of exceedance, p, is constant from year to year which leads to an average return period To equal to 1/p; this expression is far more complex under nonstationarity. Even for stationary processes, the common application of an average return period is problematic: it does not account for planning horizon, is an average value that may not be representative of the time to the next flood, and is generally not applied in other areas of water planning. We combine existing theoretical and empirical results from the literature to provide the first general, comprehensive description of the probabilistic behavior of the return period and reliability under nonstationarity. We show that under nonstationarity, the underlying distribution of the return period exhibits a more complex shape than the exponential distribution under stationary conditions. Using a nonstationary lognormal model, we document the increased complexity and challenges associated with planning for future flood events over a planning horizon. We compare application of the average return period with the more common concept of reliability and recommend replacing the average return period with reliability as a more practical way to communicate event likelihood in both stationary and nonstationary contexts.

  9. Return to sports after shoulder arthroplasty.

    PubMed

    Johnson, Christine C; Johnson, Daniel J; Liu, Joseph N; Dines, Joshua S; Dines, David M; Gulotta, Lawrence V; Garcia, Grant H

    2016-09-18

    Many patients prioritize the ability to return to sports following shoulder replacement surgeries, including total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (RTSA), and hemiarthroplasty (HA). While activity levels after hip and knee replacements have been well-established in the literature, studies on this topic in the field of shoulder arthroplasty are relatively limited. A review of the literature regarding athletic activity after shoulder arthroplasty was performed using the PubMed database. All studies relevant to shoulder arthroplasty and return to sport were included. The majority of patients returned to their prior level of activity within six months following TSA, RTSA, and shoulder HA. Noncontact, low demand activities are permitted by most surgeons postoperatively and generally have higher return rates than contact sports or high-demand activities. In some series, patients reported an improvement in their ability to participate in sports following the arthroplasty procedure. The rates of return to sports following TSA (75%-100%) are slightly higher than those reported for HA (67%-76%) and RTSA (75%-85%). Patients undergoing TSA, RTSA, and shoulder HA should be counseled that there is a high probability that they will be able to return to their preoperative activity level within six months postoperatively. TSA has been associated with higher rates of return to sports than RTSA and HA, although this may reflect differences in patient population or surgical indication.

  10. Return to sports after shoulder arthroplasty

    PubMed Central

    Johnson, Christine C; Johnson, Daniel J; Liu, Joseph N; Dines, Joshua S; Dines, David M; Gulotta, Lawrence V; Garcia, Grant H

    2016-01-01

    Many patients prioritize the ability to return to sports following shoulder replacement surgeries, including total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (RTSA), and hemiarthroplasty (HA). While activity levels after hip and knee replacements have been well-established in the literature, studies on this topic in the field of shoulder arthroplasty are relatively limited. A review of the literature regarding athletic activity after shoulder arthroplasty was performed using the PubMed database. All studies relevant to shoulder arthroplasty and return to sport were included. The majority of patients returned to their prior level of activity within six months following TSA, RTSA, and shoulder HA. Noncontact, low demand activities are permitted by most surgeons postoperatively and generally have higher return rates than contact sports or high-demand activities. In some series, patients reported an improvement in their ability to participate in sports following the arthroplasty procedure. The rates of return to sports following TSA (75%-100%) are slightly higher than those reported for HA (67%-76%) and RTSA (75%-85%). Patients undergoing TSA, RTSA, and shoulder HA should be counseled that there is a high probability that they will be able to return to their preoperative activity level within six months postoperatively. TSA has been associated with higher rates of return to sports than RTSA and HA, although this may reflect differences in patient population or surgical indication. PMID:27672564

  11. Integrating Public Perspectives in Sample Return Planning

    NASA Technical Reports Server (NTRS)

    Race, Margaret S.; MacGregor, G.

    2001-01-01

    Planning for extraterrestrial sample returns, whether from Mars or other solar system bodies, must be done in a way that integrates planetary protection concerns with the usual mission technical and scientific considerations. Understanding and addressing legitimate societal concerns about the possible risks of sample return will be a critical part of the public decision making process ahead. This paper presents the results of two studies, one with lay audiences, the other with expert microbiologists, designed to gather information, on attitudes and concerns about sample return risks and planetary protection. Focus group interviews with lay subjects, using generic information about Mars sample return and a preliminary environmental impact assessment, were designed to obtain an indication of how the factual content is perceived and understood by the public. A research survey of microbiologists gathered information on experts' views and attitudes about sample return, risk management approaches and space exploration risks. These findings, combined with earlier research results on risk perception, will be useful in identifying levels of concern and potential conflicts in understanding between experts and the public about sample return risks. The information will be helpful in guiding development of the environmental impact statement and also has applicability to proposals for sample return from other solar system bodies where scientific uncertainty about extraterrestrial life may persist at the time of mission planning.

  12. Return to Flying Duties Following Centrifuge or Vibration Exposures

    NASA Technical Reports Server (NTRS)

    Scheuring, Richard A.; Clarke, Jonathan; Jones, Jeffrey A.

    2009-01-01

    Introduction: In an effort to determine the human performance limits for vibration in spacecraft being developed by NASA, astronauts were evaluated during a simulated launch profile in a centrifuge/vibration environment and separate vibration-only simulation. Current USAF and Army standards for return to flight following centrifuge exposures require 12-24 hours to pass before a crewmember may return to flying duties. There are no standards on vibration exposures and return to flying duties. Based on direct observation and provocative neurological testing of the astronauts, a new standard for return to flying duties following centrifuge and/or vibration exposures was established. Methods: 13 astronaut participants were exposed to simulated launch profiles in a + 3.5 Gx bias centrifuge/vibration environment and separately on a vibration table at the NASA-Ames Research Center. Each subject had complete neurological evaluations pre- and post-exposure for the centrifuge/vibration runs with the NASA neurological function rating scale (NFRS). Subjects who participated in the vibration-only exposures had video oculography performed with provocative maneuvers in addition to the NFRS. NFRS evaluations occurred immediately following each exposure and at 1 hour post-run. Astronauts who remained symptomatic at 1 hour had repeat NFRS performed at 1 hour intervals until the crewmember was asymptomatic. Results: Astronauts in the centrifuge/vibration study averaged a 3-5 point increase in NFRS scores immediately following exposure but returned to baseline 3 hours post-run. Subjects exposed to the vibration-only simulation had a 1-3 point increase following exposure and returned to baseline within 1-2 hours. Pre- and post- vibration exposure video oculography did not reveal any persistent ocular findings with provocative testing 1 hour post-exposure. Discussion: Based on direct observations and objective measurement of neurological function in astronauts following simulated launch

  13. Grand valley irrigation return flow case study

    SciTech Connect

    Keys, J.W.

    1981-06-01

    Irrigation water supply is furnished annually to about 71,500 acres of land in the Grand Valley of western Colorado. Return flows from that irrigation contribute about 780,000 tpy of salt to the Colorado River, causing an increase of 77 mg/l in the salinity concentration at Imperial Dam. A case study of water quality in this region is focused on: water quality data for irrigation and return flows/ identification of regulations that affect irrigation and return flows/ and a proposed program for controlling salinity levels. (1 map, 9 references, 8 tables)

  14. Rejected asylum seekers: the problem of return.

    PubMed

    Noll, G

    1999-01-01

    "During this decade the return of rejected asylum seekers has become an issue of increasing concern to major asylum states in the industrialized world. This article exposes the various political and legal approaches taken by returning states as well as the constraints emerging from human rights law. As a rigid control paradigm and related enforcement practices entail a considerable risk of human rights violations, it seems reasonable to focus on measures enhancing the voluntary compliance of all actors involved with norms governing return." (EXCERPT)

  15. Technology for return of planetary samples

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Technological requirements of a planetary return sample mission were studied. The state-of-the-art for problems unique to this class of missions was assessed and technological gaps were identified. The problem areas where significant advancement of the state-of-the-art is required are: life support for the exobiota during the return trip and within the Planetary Receiving Laboratory (PRL); biohazard assessment and control technology; and quarantine qualified handling and experimentation methods and equipment for studying the returned sample in the PRL. Concepts for solving these problems are discussed.

  16. Return to Play Following Hip Arthroscopy.

    PubMed

    Lee, Simon; Kuhn, Andrew; Draovitch, Pete; Bedi, Asheesh

    2016-10-01

    Femoroacetabular impingement may be particularly disabling to the high-demand athlete, especially those with significant cutting and pivoting requirements. If nonoperative treatment fails to adequately alleviate symptoms or sufficiently restore function in the athlete, hip arthroscopy can lead to improved pain, improved range of motion, and high rates of return to play with proper postoperative rehabilitation. The rate of return to previous level of competition is also high with accurate diagnosis and well-executed correction of deformity. A clear understanding of the etiology, diagnosis, management, and outcomes is essential for clinicians to optimally help patients to return to play.

  17. FE Simulation of SMA Seal for Mars Sample Return

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Younse, Paulo; Bhandari, Pradeep

    2013-01-01

    Several NASA rovers and landers have been on Mars and performed successful in-situ exploration. Returning Martian samples to Earth for extensive analysis is of great interest to the planetary science community. Current Mars sample return architecture would require leaving the acquired samples on Mars for years before being retrieved by subsequent mission. Each sample would be sealed securely to keep its integrity. A reliable seal technique that does not affect the integrity of the samples and uses a simple low-mass tool is required. The shape memory alloy (SMA) seal technique is a promising candidate. A study of the thermal performances of several primary designs of a SMA seal for sample tubes by finite element (FE) simulation are presented in this paper. The results show sealing the sample tube by SMA plugs and controlling the sample temperature below the allowed temperature level are feasible.

  18. An Integrated Tool for System Analysis of Sample Return Vehicles

    NASA Technical Reports Server (NTRS)

    Samareh, Jamshid A.; Maddock, Robert W.; Winski, Richard G.

    2012-01-01

    The next important step in space exploration is the return of sample materials from extraterrestrial locations to Earth for analysis. Most mission concepts that return sample material to Earth share one common element: an Earth entry vehicle. The analysis and design of entry vehicles is multidisciplinary in nature, requiring the application of mass sizing, flight mechanics, aerodynamics, aerothermodynamics, thermal analysis, structural analysis, and impact analysis tools. Integration of a multidisciplinary problem is a challenging task; the execution process and data transfer among disciplines should be automated and consistent. This paper describes an integrated analysis tool for the design and sizing of an Earth entry vehicle. The current tool includes the following disciplines: mass sizing, flight mechanics, aerodynamics, aerothermodynamics, and impact analysis tools. Python and Java languages are used for integration. Results are presented and compared with the results from previous studies.

  19. Flight status of robotic asteroid sample return mission Hayabusa2

    NASA Astrophysics Data System (ADS)

    Tsuda, Yuichi; Nakazawa, Satoru; Kushiki, Kenichi; Yoshikawa, Makoto; Kuninaka, Hitoshi; Watanabe, Seiichiro

    2016-10-01

    The Japan Aerospace Exploration Agency launched the asteroid sample return spacecraft "Hayabusa2" on December 3, 2014. Hayabusa2 will reach the C-type asteroid 1999 JU3 in 2018, and return back to the Earth in 2020. Sample collections from three sites, four surface rovers deployment and a 4 MJ-class kinetic impact crater generation are planned in the 1.5 years of the asteroid-proximity operation. The mission objective of Hayabusa2 has three aspects, science, engineering and exploration, all of which would be expanded by the successful round-trip journey. This paper describes the outline of the Hayabusa2 mission and the current flight status after the seven month of the interplanetary cruise.

  20. 27 CFR 25.164 - Quarterly and semimonthly returns.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS BEER Tax on Beer Preparation and Remittance of Tax Returns... on beer (unless prepaid) by return on Form 5000.24. The brewer shall file Form 5000.24 as a return... file a return on Form 5000.24 for each return period even though no beer was removed for consumption...

  1. 27 CFR 25.164 - Quarterly and semimonthly returns.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL BEER Tax on Beer Preparation and Remittance of Tax Returns... on beer (unless prepaid) by return on Form 5000.24. The brewer shall file Form 5000.24 as a return... file a return on Form 5000.24 for each return period even though no beer was removed for consumption...

  2. 27 CFR 25.164 - Quarterly and semimonthly returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL BEER Tax on Beer Preparation and Remittance of Tax Returns... on beer (unless prepaid) by return on Form 5000.24. The brewer shall file Form 5000.24 as a return... file a return on Form 5000.24 for each return period even though no beer was removed for consumption...

  3. 27 CFR 25.164 - Quarterly and semimonthly returns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS BEER Tax on Beer Preparation and Remittance of Tax Returns... on beer (unless prepaid) by return on Form 5000.24. The brewer shall file Form 5000.24 as a return... file a return on Form 5000.24 for each return period even though no beer was removed for consumption...

  4. 27 CFR 40.355 - Return of manufacturer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., a semimonthly tax return on TTB Form 5000.24. A return shall be filed for each semimonthly return... for that particular return period. (b) Waiver from filing. The manufacturer need not file a return for... period and the appropriate TTB officer has granted a waiver from filing in response to a written...

  5. 27 CFR 40.355 - Return of manufacturer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., a semimonthly tax return on TTB Form 5000.24. A return shall be filed for each semimonthly return... for that particular return period. (b) Waiver from filing. The manufacturer need not file a return for... period and the appropriate TTB officer has granted a waiver from filing in response to a written...

  6. Reliability estimation from field return data.

    PubMed

    Wilson, Simon; Joyce, Toby; Lisay, Ed

    2009-09-01

    In this article statistical inference for the failure time distribution of a product from "field return data", that records the time between the product being shipped and returned for repair or replacement, is described. The problem that is addressed is that the data are not failure times because they also include the time that it took to ship and install the product and then to return it to the manufacturer for repair or replacement. The inference attempts to infer the distribution of time to failure (that is, from installation to failure) from the data when in addition there are separate data on the times from shipping to installation, and from failure to return. The method is illustrated with data from units installed in a telecommunications network.

  7. Self-Checks Help Spot Melanoma's Return

    MedlinePlus

    ... news/fullstory_163682.html Self-Checks Help Spot Melanoma's Return Patient-detected symptoms were most common way ... Feb. 20, 2017 (HealthDay News) -- Self-checks by melanoma skin cancer patients play an important role in ...

  8. Preparing for the Meteoritic Return of Stardust

    NASA Astrophysics Data System (ADS)

    Jenniskens, P.; Kontinos, D.; Jordan, D.; Wright, M.; Olejniczak, J.; Raiche, G.; Wercinski, P.; Desai, P. N.; Taylor, M. J., Stenbaek-Nielsen, H. C.; McHarg, M. G.; Abe, S.; Rairden, R. L.; Albers, J.; Winter, M. And, Harms, F.; Wolf, J.; Revelle, D. O.; Gural, P.; Dantowitz, R.; Rietmeijer, F.; Hladiuk, D.; Hildebrand, A. R.

    2007-01-01

    The hypervelocity entry of a sample return capsule on its way back from interplanetary space acts as an artificial meteor, with flow conditions similar to natural m-sized meteoroids. Unlike natural fireballs, a sample return capsule arrives at a known time and its shock emissions and ablation can be studied without the confusion of fragmentation and the obscuring emissions from ablated meteoric metals. The entry of the Stardust Sample Return Capsule (SRC) on Sunday January 15, 2006, was also a real-life test of key risk drivers for future Thermal Protection System (TPS) design, by measuring the amount of radiative heat flux and the ablation response of the TPS. This paper presents results from the calculations made to predict the expected meteoric emissions for the Stardust SRC entry and re-evaluates the surface temperature measurements obtained during a prior mission that observed the Genesis sample return.

  9. Phootprint: A European Phobos Sample Return Mission

    NASA Astrophysics Data System (ADS)

    Barraclough, S.; Ratcliffe, A.; Buchwald, R.; Scheer, H.; Chapuy, M.; Garland, M.; Rebuffat, D.

    2014-06-01

    Phootprint is an ESA funded feasibility study for a European Phobos Sample Return Mission. A complete system design has been performed including ERC, Landing Leg, Sample Acquisition System and GNC Proximity Operations.

  10. Hydraulic Fracturing Return Waters and Legacy Landscapes

    NASA Astrophysics Data System (ADS)

    Bain, D. J.; Michanowicz, A. R.; Ferrar, K. J.

    2010-12-01

    Hydraulic fracturing of gas-bearing shales to enhance recovery is growing increasingly common globally. However, disposal of return water remains a challenge, particularly in humid environments where evapoconcentration potential is limited. Further, return water typical of recent activity in the Marcellus Shale in the eastern United States is substantially saltier relative to other shales where hydraulic fracturing has been employed. This presentation explores scenarios of both traditional return water disposal and accidental releases of return water to fluvial systems using simple exchange modeling, with particular attention to conditions in landscapes typical of Marcellus country. That is, these simulations will incorporate a historic context, acknowledging decades of coal extraction from surface and sub-surface mines and energy production via combustion of said coal. The interactions between “naturally attenuated” historic contamination and rapidly changing water chemistry are critical to accurate risk assessment in this uncertain environment.

  11. STS-26: The return to flight

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The major activities leading up to the return to flight of the Space Shuttles are summarized. Major orbiter modifications and solid rocket motor redesign are described. Shuttle payloads are discussed briefly. Also provided are the biographies of the crew.

  12. Mercury Sample Return using Solar Sails

    NASA Technical Reports Server (NTRS)

    Montgomery, Edward E.; Young, Roy M.; Adams, Charles L.

    2006-01-01

    A conventional Mercury sample return mission requires significant launch mass due to the large deltav required for the outbound and return trips, and the large mass of a planetary lander and ascent vehicle. Solar sailing can be used to reduce lander mass allocation by delivering the lander to a low, thermally safe orbit close to the terminator. Propellant mass is not an issue for solar sails so a sample can be returned relatively easily, without resorting to lengthy, multiple gravity assists. The initial Mercury sample return studies reported here were conducted under ESA contract ESTEC/16534/02/NL/NR, PI Colin McInnes, Technical Officer Peter Falkner. Updated solar sail capabilities were developed under the Ground System Demonstration program, funded by the NASA's In-Space Propulsion Technology (ISPT) Program.

  13. Hayabusa: Navigation Challenges for Earth Return

    NASA Technical Reports Server (NTRS)

    Haw, Robert J.; Bhaskaran, S.; Strauss, W.; Sklyanskiy, E.; Graat, E. J.; Smith, J. J.; Menom, P.; Ardalan, S.; Ballard, C.; Williams, P.; Kawaguchi, J.; Makoto, Y.; Ohnishi, T.

    2011-01-01

    Hayabusa was a JAXA sample-return mission to Itokawa navigated, in part, by JPL personnel. Hayabusa survived several near mission-ending failures at Itokawa yet returned to Earth with an asteroid regolith sample on June 13, 2010. This paper describes NASA/JPL's participation in the Hayabusa mission during the last 100 days of its mission, wherein JPL provided tracking data and orbit determination, plus verification of maneuver design and entry, descent and landing.

  14. 26 CFR 1.6033-4 - Required use of magnetic media for returns by organizations required to file returns under...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 13 2010-04-01 2010-04-01 false Required use of magnetic media for returns by... Returns § 1.6033-4 Required use of magnetic media for returns by organizations required to file returns under section 6033. The return of an organization that is required to be filed on magnetic media...

  15. 26 CFR 1.6033-4 - Required use of magnetic media for returns by organizations required to file returns under...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 13 2011-04-01 2011-04-01 false Required use of magnetic media for returns by...) Information Returns § 1.6033-4 Required use of magnetic media for returns by organizations required to file returns under section 6033. The return of an organization that is required to be filed on magnetic...

  16. 26 CFR 1.6033-4 - Required use of magnetic media for returns by organizations required to file returns under...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 13 2014-04-01 2014-04-01 false Required use of magnetic media for returns by...) Information Returns § 1.6033-4 Required use of magnetic media for returns by organizations required to file returns under section 6033. The return of an organization that is required to be filed on magnetic...

  17. 26 CFR 1.6033-4 - Required use of magnetic media for returns by organizations required to file returns under...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 13 2013-04-01 2013-04-01 false Required use of magnetic media for returns by...) Information Returns § 1.6033-4 Required use of magnetic media for returns by organizations required to file returns under section 6033. The return of an organization that is required to be filed on magnetic...

  18. 26 CFR 1.6033-4 - Required use of magnetic media for returns by organizations required to file returns under...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 13 2012-04-01 2012-04-01 false Required use of magnetic media for returns by...) Information Returns § 1.6033-4 Required use of magnetic media for returns by organizations required to file returns under section 6033. The return of an organization that is required to be filed on magnetic...

  19. Comet nucleus and asteroid sample return missions

    NASA Astrophysics Data System (ADS)

    1992-06-01

    Three Advanced Design Projects have been completed this academic year at Penn State. At the beginning of the fall semester the students were organized into eight groups and given their choice of either a comet nucleus or an asteroid sample return mission. Once a mission had been chosen, the students developed conceptual designs. These were evaluated at the end of the fall semester and combined into three separate mission plans, including a comet nucleus same return (CNSR), a single asteroid sample return (SASR), and a multiple asteroid sample return (MASR). To facilitate the work required for each mission, the class was reorganized in the spring semester by combining groups to form three mission teams. An integration team consisting of two members from each group was formed for each mission so that communication and information exchange would be easier among the groups. The types of projects designed by the students evolved from numerous discussions with Penn State faculty and mission planners at the Johnson Space Center Human/Robotic Spacecraft Office. Robotic sample return missions are widely considered valuable precursors to manned missions in that they can provide details about a site's environment and scientific value. For example, a sample return from an asteroid might reveal valuable resources that, once mined, could be utilized for propulsion. These missions are also more adaptable when considering the risk to humans visiting unknown and potentially dangerous locations, such as a comet nucleus.

  20. Comet nucleus and asteroid sample return missions

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Three Advanced Design Projects have been completed this academic year at Penn State. At the beginning of the fall semester the students were organized into eight groups and given their choice of either a comet nucleus or an asteroid sample return mission. Once a mission had been chosen, the students developed conceptual designs. These were evaluated at the end of the fall semester and combined into three separate mission plans, including a comet nucleus same return (CNSR), a single asteroid sample return (SASR), and a multiple asteroid sample return (MASR). To facilitate the work required for each mission, the class was reorganized in the spring semester by combining groups to form three mission teams. An integration team consisting of two members from each group was formed for each mission so that communication and information exchange would be easier among the groups. The types of projects designed by the students evolved from numerous discussions with Penn State faculty and mission planners at the Johnson Space Center Human/Robotic Spacecraft Office. Robotic sample return missions are widely considered valuable precursors to manned missions in that they can provide details about a site's environment and scientific value. For example, a sample return from an asteroid might reveal valuable resources that, once mined, could be utilized for propulsion. These missions are also more adaptable when considering the risk to humans visiting unknown and potentially dangerous locations, such as a comet nucleus.

  1. 49 CFR 236.720 - Circuit, common return.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Circuit, common return. A term applied where one wire is used for the return of more than one electric circuit. ... 49 Transportation 4 2013-10-01 2013-10-01 false Circuit, common return. 236.720 Section...

  2. 49 CFR 236.720 - Circuit, common return.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Circuit, common return. A term applied where one wire is used for the return of more than one electric circuit. ... 49 Transportation 4 2012-10-01 2012-10-01 false Circuit, common return. 236.720 Section...

  3. 49 CFR 236.720 - Circuit, common return.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Circuit, common return. A term applied where one wire is used for the return of more than one electric circuit. ... 49 Transportation 4 2014-10-01 2014-10-01 false Circuit, common return. 236.720 Section...

  4. 49 CFR 236.720 - Circuit, common return.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Circuit, common return. A term applied where one wire is used for the return of more than one electric circuit. ... 49 Transportation 4 2011-10-01 2011-10-01 false Circuit, common return. 236.720 Section...

  5. Doppler shifts of radar return from the sea surface

    NASA Astrophysics Data System (ADS)

    Ermakov, S. A.; Kapustin, I. A.; Molkov, A. A.; Sergievskaya, I. A.; Shomina, O. V.

    2016-10-01

    Investigation of the Doppler shift of radar return from the sea surface is very important for better understanding of capabilities of exploitation of microwave radar for measuring velocities of marine currents. Here new field experiments carried out from a Platform on the Black Sea with a coherent X-band scatterometer, and a Doppler multifrequency (X- /C-/S-band) dual-polarized radar recently designed at IAP RAS are discussed. It is shown that the radar return contains both Bragg (polarized) and non polarized scattering components, presumably giving different contributions to radar Doppler shifts. Radar Doppler shifts were estimated using two different definitions as a) a frequency of the "centre of gravity" of an instantaneous radar return spectrum (ASIS) averaged over periods of dominant wind waves and b) the "centre of gravity" of the averaged over dominant wave periods spectrum (SAS). The ASIS and SAS values for both VV and HH-polarizations are shown to be different due to effects of radar backscatter modulation by dominant (long) wind waves. The radar Modulation Transfer Function (MTF) has been analyzed from experimental data and difference between SAS- and ASIS-values has been satisfactory explained using the measured MTF-values. It is obtained that experimental values of ASIS can be satisfactory described by the Bragg model despite the significant contribution of NP component to the radar backscatter. A physical explanation of the effect is given.

  6. Return to Play After Liver and Spleen Trauma

    PubMed Central

    Juyia, Rushad F.; Kerr, Hamish A.

    2014-01-01

    Context: Sport-related spleen and liver injuries pose a challenge for the physician. Although rare, these injuries can have serious and even life-threatening outcomes if not accurately diagnosed and managed in a timely fashion. Currently, there are no evidence-based guidelines on duration and intensity of restricted activity and return to play after spleen and liver injury. In addition, there is controversy on follow-up imaging after injury. Evidence Acquisition: PubMed was searched using the terms splenic or spleen and trauma and hepatic or liver and trauma from 1980 to 2013. The citations from sentinel papers were also reviewed. Study Design: Clinical review. Level of Evidence: Level 3. Results: Ultrasound is ideal in the unstable athlete. Nonoperative management of blunt splenic and hepatic injuries is recommended for hemodynamically stable patients regardless of injury grade, patient age, or presence of associated injuries. Follow-up imaging is not routinely recommended unless clinically indicated. Athletes may engage in light activity for the first 3 months after injury and then gradual return to unrestricted activity as tolerated. High-level athletes may choose splenectomy or serial imaging for faster return to play. Conclusion: Intravenous contrast-enhanced computed tomography is the diagnostic imaging modality of choice in stable athletes with blunt abdominal trauma. Strength-of-Recommendation Taxonomy: C. PMID:24790694

  7. The propagation speed of a positive lightning return stroke

    NASA Technical Reports Server (NTRS)

    Idone, Vincent P.; Orville, Richard E.; Mach, Douglas M.; Rust, W. David

    1987-01-01

    The first direct determination of the propagation speed of a lightning return stroke lowering positive charge to ground has been made. This stroke was the third of eight otherwise negative strokes in a triggered lightning flash initiated at the Kennedy Space Center, FL. Two independent optical systems, one photographic and the other photoelectric, yielded common recordings for the third and fourth strokes; the respective two-dimensional return stroke propagation speeds were 1.0 vs 0.93 x 10 to the 8th m/s for the positive (third) stroke and 1.0 vs 1.0 x 10 to the 8th m/s for the fourth stroke. Using fast electric-field data, the positive stroke peak current was estimated to be 21 kA. Photoelectric data only yielded propagation speeds of 1.4, 1.6, 1.2, 1.3, 1.0 and 0.90 x 10 to the 8th m/s for the first, second and fifth through eighth return strokes, respectively.

  8. Comet Odyssey: Comet Surface Sample Return

    NASA Astrophysics Data System (ADS)

    Weissman, Paul R.; Bradley, J.; Smythe, W. D.; Brophy, J. R.; Lisano, M. E.; Syvertson, M. L.; Cangahuala, L. A.; Liu, J.; Carlisle, G. L.

    2010-10-01

    Comet Odyssey is a proposed New Frontiers mission that would return the first samples from the surface of a cometary nucleus. Stardust demonstrated the tremendous power of analysis of returned samples in terrestrial laboratories versus what can be accomplished in situ with robotic missions. But Stardust collected only 1 milligram of coma dust, and the 6.1 km/s flyby speed heated samples up to 2000 K. Comet Odyssey would collect two independent 800 cc samples directly from the surface in a far more benign manner, preserving the primitive composition. Given a minimum surface density of 0.2 g/cm3, this would return two 160 g surface samples to Earth. Comet Odyssey employs solar-electric propulsion to rendezvous with the target comet. After 180 days of reconnaissance and site selection, the spacecraft performs a "touch-and-go” maneuver with surface contact lasting 3 seconds. A brush-wheel sampler on a remote arm collects up to 800 cc of sample. A duplicate second arm and sampler collects the second sample. The samples are placed in a return capsule and maintained at colder than -70 C during the return flight and at colder than -30 C during re-entry and for up to six hours after landing. The entire capsule is then refrigerated and transported to the Astromaterials Curatorial Facility at NASA/JSC for initial inspection and sample analysis by the Comet Odyssey team. Comet Odyssey's planned target was comet 9P/Tempel 1, with launch in December 2017 and comet arrival in June 2022. After a stay of 300 days at the comet, the spacecraft departs and arrives at Earth in May 2027. Comet Odyssey is a forerunner to a flagship Cryogenic Comet Sample Return mission that would return samples from deep below the nucleus surface, including volatile ices. This work was supported by internal funds from the Jet Propulsion Laboratory.

  9. Rossby rip currents

    NASA Astrophysics Data System (ADS)

    Marshall, David P.; Vogel, Bendix; Zhai, Xiaoming

    2013-08-01

    Oceanic Rossby waves and eddies flux energy and fluid westward, the latter through the Stokes drift or bolus transport. While the wave energy is largely dissipated at the western boundary, mass conservation requires that the fluid be returned offshore through Rossby rip currents. The form and magnitude of these rip currents are investigated through linear Rossby wave theory, a nonlinear numerical model, and analysis of sea surface height satellite observations. The net eastward volume transport by Rossby rip currents over the global ocean is estimated to be of order 10 Sv (1 Sv ≡106 m3 s-1). In an eddying ocean, both the westward Stokes drift and eastward rip currents can assume the form of banded quasi-zonal jets.

  10. Groundbreaking Mars Sample Return for Science and Human Exploration

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara; Draper, David; Eppler, Dean; Treiman, Allan

    2012-01-01

    Partnerships between science and human exploration have recent heritage for the Moon (Lunar Precursor Robotics Program, LPRP) and nearearth objects (Exploration Precursor Robotics Program, xPRP). Both programs spent appreciable time and effort determining measurements needed or desired before human missions to these destinations. These measurements may be crucial to human health or spacecraft design, or may be desired to better optimize systems designs such as spacesuits or operations. Both LPRP and xPRP recommended measurements from orbit, by landed missions and by sample return. LPRP conducted the Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS) missions, providing high-resolution visible imagery, surface and subsurface temperatures, global topography, mapping of possible water ice deposits, and the biological effects of radiation [1]. LPRP also initiated a landed mission to provide dust and regolith properties, local lighting conditions, assessment of resources, and demonstration of precision landing [2]. This mission was canceled in 2006 due to funding shortfalls. For the Moon, adequate samples of rocks and regolith were returned by the Apollo and Luna programs to conduct needed investigations. Many near-earth asteroids (NEAs) have been observed from the Earth and several have been more extensively characterized by close-flying missions and landings (NEAR, Hayabusa, Rosetta). The current Joint Robotic Precursor Activity program is considering activities such as partnering with the New Frontiers mission OSIRIS-Rex to visit a NEA and return a sample to the Earth. However, a strong consensus of the NEO User Team within xPRP was that a dedicated mission to the asteroid targeted by humans is required [3], ideally including regolith sample return for more extensive characterization and testing on the Earth.

  11. Return on investment from employment of community health workers.

    PubMed

    Rush, Carl H

    2012-01-01

    Community Health Workers (CHWs) are gaining acceptance in the US health care system, but have been subject to challenges as to their "cost-effectiveness." This situation is shifting, with a growing body of published evidence as to the effectiveness of CHWs, but much of the evidence of cost savings from employing CHWs is still unpublished. Return on investment analysis for CHWs must consider a range of possible CHW roles and stakeholder points of view. Current trends suggest we may be entering a new era of acceptance in which a generally lower threshold of evidence is required in proposing the employment of CHWs.

  12. A narrative review of sports-related concussion and return-to-play testing with asymptomatic athletes

    PubMed Central

    Porcher, Nathan J.; Solecki, Thomas J.

    2013-01-01

    Objective The purpose of this literature review was to demonstrate, through examples in the current literature, the cumulative and long-term effects of multiple concussions, postinjury protocols, and the efficacy of current and past return-to-play guidelines. Methods A PubMed search was performed using the keywords and key phrases: concussions and long-term effects, concussions and return to play, and multiple concussions. We limited the search to articles that had been published from August 2007 to August 2012 and were specific to human participants. Of the 450 total articles that the search returned, we selected studies specifically demonstrating athletes who were symptom-free, passed neuropsychological testing, returned to play, and were tested in measures of postural control, transcranial magnetic stimulation, electroencephalographic studies, and magnetic resonance imaging spectroscopy. Results Selected studies show evidence that, although a previously concussed athlete may be symptom-free and returned to a neuropsychological baseline, the athlete may continue to have prolonged neurological abnormalities that could disqualify them from being ready to return to play. Conclusion It appears that some neurological deficits persist beyond the current return-to-play standards and that discrepancy exists between common practices of returning athletes to competition and new standards of published research. PMID:24396328

  13. In-line beam current monitor

    DOEpatents

    Ekdahl, Jr., Carl A.; Frost, Charles A.

    1986-01-01

    An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

  14. In-line beam current monitor

    DOEpatents

    Ekdahl, C.A. Jr.; Frost, C.A.

    1984-11-13

    An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

  15. 27 CFR 479.151 - Failure to make returns: Substitute returns.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2014-04-01 2014-04-01 false Failure to make returns: Substitute returns. 479.151 Section 479.151 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS,...

  16. 27 CFR 479.151 - Failure to make returns: Substitute returns.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2011-04-01 2010-04-01 true Failure to make returns: Substitute returns. 479.151 Section 479.151 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS,...

  17. 27 CFR 479.151 - Failure to make returns: Substitute returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2013-04-01 2013-04-01 false Failure to make returns: Substitute returns. 479.151 Section 479.151 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS,...

  18. 27 CFR 479.151 - Failure to make returns: Substitute returns.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2012-04-01 2010-04-01 true Failure to make returns: Substitute returns. 479.151 Section 479.151 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS,...

  19. 27 CFR 479.151 - Failure to make returns: Substitute returns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Failure to make returns: Substitute returns. 479.151 Section 479.151 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS,...

  20. 75 FR 76940 - Specified Tax Return Preparers Required To File Individual Income Tax Returns Using Magnetic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-10

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE TREASURY Internal Revenue Service 26 CFR Parts 1 and 301 RIN 1545-BJ52 Specified Tax Return Preparers Required To File Individual Income Tax Returns Using Magnetic Media; Correction AGENCY: Internal Revenue...

  1. Return Migration: A Study of College Graduates Returning to Rural U.S. Homes

    ERIC Educational Resources Information Center

    Mahoney, Elizabeth D.

    2009-01-01

    The purpose of this study is to explore perceptions of return migration experiences and gain knowledge from rural residents who have left to obtain a college education and start careers in non-rural areas, and who then returned to their rural hometowns with the social and economic benefits of a college education, and other valuable resources. This…

  2. 12 CFR 229.31 - Returning bank's responsibility for return of checks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Returning bank's responsibility for return of checks. 229.31 Section 229.31 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC)...

  3. 26 CFR 1.6013-2 - Joint return after filing separate return.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... adopt and use the last-in, first-out inventory method under section 472, this election may not be...(b), any election, other than the election to file a separate return, made by either spouse in his... such spouse shall not be changed in the making of the joint return where such election would have...

  4. 26 CFR 1.6013-2 - Joint return after filing separate return.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... adopt and use the last-in, first-out inventory method under section 472, this election may not be...(b), any election, other than the election to file a separate return, made by either spouse in his... such spouse shall not be changed in the making of the joint return where such election would have...

  5. 76 FR 31543 - Disclosure of Returns and Return Information to Designee of Taxpayer; Hearing Cancellation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-01

    ... addressed. As of May 23, 2011, no one has requested to speak. Therefore, the public hearing scheduled for...: Cancellation of a notice of public hearing on a proposed rulemaking. SUMMARY: This document cancels a public... authorizations permitting disclosure of returns and return information. DATES: The public hearing,...

  6. Planetary Protection Technology for Mars Sample Return

    NASA Technical Reports Server (NTRS)

    Gershman, Robert

    2005-01-01

    The NASA Mars Exploration Program has recently adopted a plan that includes a first Mars sample return (MSR) mission proposed for launch in 2013. Such a mission would deal with two new categories of planetary protection requirements: (1) assuring a very low probability of inadvertent release of the sample in order to provide extra protection against the extremely unlikely possibility of biological hazards in the returned material and (2) keeping the samples free of round-trip Earth organisms to facilitate confirmation of safety after return to Earth. This paper describes the planetary-protection-related technical challenges awaiting any MSR mission and describes work in progress on technology needed to meet these challenges. New technology is needed for several functions. Containment assurance requires breaking the chain of contact with Mars: the exterior of the sample container must not be contaminated with Mars material either during the loading process or during launch from the Mars surface.

  7. SOCCER: Comet Coma Sample Return Mission

    NASA Technical Reports Server (NTRS)

    Albee, A. L.; Uesugi, K. T.; Tsou, Peter

    1994-01-01

    Comets, being considered the most primitive bodies in the solar system, command the highest priority among solar system objects for studying solar nebula evolution and the evolution of life through biogenic elements and compounds. Sample Of Comet Coma Earth Return (SOCCER), a joint effort between NASA and the Institute of Space and Astronautical Science (ISAS) in Japan, has two primary science objectives: (1) the imaging of the comet nucleus and (2) the return to Earth of samples of volatile species and intact dust. This effort makes use of the unique strengths and capabilities of both countries in realizing this important quest for the return of samples from a comet. This paper presents an overview of SOCCER's science payloads, engineering flight system, and its mission operations.

  8. A wave function for stock market returns

    NASA Astrophysics Data System (ADS)

    Ataullah, Ali; Davidson, Ian; Tippett, Mark

    2009-02-01

    The instantaneous return on the Financial Times-Stock Exchange (FTSE) All Share Index is viewed as a frictionless particle moving in a one-dimensional square well but where there is a non-trivial probability of the particle tunneling into the well’s retaining walls. Our analysis demonstrates how the complementarity principle from quantum mechanics applies to stock market prices and of how the wave function presented by it leads to a probability density which exhibits strong compatibility with returns earned on the FTSE All Share Index. In particular, our analysis shows that the probability density for stock market returns is highly leptokurtic with slight (though not significant) negative skewness. Moreover, the moments of the probability density determined under the complementarity principle employed here are all convergent - in contrast to many of the probability density functions on which the received theory of finance is based.

  9. Earth Entry Vehicle for Mars Sample Return

    NASA Technical Reports Server (NTRS)

    Mitcheltree, R. A.; Braun, R. D.; Hughes. S. J.; Simonsen, L. C.

    2000-01-01

    The driving requirement for design of a Mars Sample return mission is assuring containment of the returned samples. The impact of this requirement on developmental costs, mass allocation, and design approach of the Earth Entry Vehicle is significant. A simple Earth entry vehicle is described which can meet these requirements and safely transport the Mars Sample Return mission's sample through the Earth's atmosphere to a recoverable location on the surface. Detailed analysis and test are combined with probabilistic risk assessment to design this entirely passive concept that circumvents the potential failure modes of a parachute terminal descent system. The design also possesses features that mitigate other risks during the entry, descent, landing and recovery phases. The results of a full-scale drop test are summarized.

  10. Rapid impactor sample return (RISR) mission scenario

    NASA Astrophysics Data System (ADS)

    Walker, James D.; Freitas, Christopher J.; Tapley, Mark B.

    2004-01-01

    Due to the long lead time and great expense of traditional sample return mission plans to Mars or other astronomical bodies, there is a need for a new and innovative way to return materials, potentially at a lower cost. The Rapid Impactor Sample Return (RISR) mission is one such proposal. The general mission scenario involves a single pass of Mars, a Martian moon or an asteroid at high speeds (7 km/s), with the sample return vehicle skimming just 1 or 2 m above a high point (such as a top ridge on Olympus Mons on Mars) and releasing an impactor. The impactor strikes the ground, throwing up debris. The debris with roughly the same forward velocity will be captured by the sample return vehicle and returned to Earth. There is no delay or orbit in the vicinity of Mars or the asteroid: RISR is a one-pass mission. This paper discusses some of the details of the proposal. Calculations are presented that address the question of how much material can be recovered with this technique. There are concerns about the effect of Mars tenuous atmosphere. However, it will be noted that such issues do not occur for RISR style missions to Phobos, Deimos, or asteroids and Near Earth Objects (NEOs). Recent test results in the missile defense community (IFTs 6-8 in 2001, 2002) have scored direct hits at better than 1 m accuracy with closing velocities of 7.6 km/s, giving the belief that accuracy and sensing issues are developed to a point that the RISR mission scenario is feasible.

  11. Immediate return preference emerged from a synaptic learning rule for return maximization.

    PubMed

    Yamaguchi, Yoshiya; Aihara, Takeshi; Sakai, Yutaka

    2015-02-01

    Animals including human often prefer immediate returns to larger delayed returns. It holds true in the human communications. Standard interpretation of the immediate return preference is that an animal might subjectively discount the value of a delayed reward, and that might choose the larger valued one. The interpretation has been successfully applied to explain behavior of many species including human. However, the description is not necessarily sufficient to apply for interactions of individuals. This study adopts a different approach to seek a possibility that immediate return preference may be reproduced by learning rule to maximize objective outcomes. We show that a synaptic learning rule to achieve the temporal difference (TD) learning for outcome maximization fails the maximization and exhibits immediate return preference if the context is not properly represented as a internal state.

  12. Multiple Approaches to Down Sizing of the Lunar Sample Return Collection

    NASA Technical Reports Server (NTRS)

    Lofgren, Gary E.; Horz, F.

    2010-01-01

    Future Lunar missions are planned for at least 7 days, significantly longer than the 3 days of the later Apollo missions. The last of those missions, A-17, returned 111 kg of samples plus another 20 kg of containers. The current Constellation program requirements for return weight for science is 100 kg with the hope of raising that limit to near 250 kg including containers and other non-geological materials. The estimated return weight for rock and soil samples will, at best, be about 175 kg. One method proposed to accomplish down-sizing of the collection is the use of a Geo-Lab in the lunar habitat to complete a preliminary examination of selected samples and facilitate prioritizing the return samples.

  13. Deciphering Martian climatic history using returned samples

    NASA Technical Reports Server (NTRS)

    Paige, D. A.; Krieger, D. B.; Brigham, C. A.

    1988-01-01

    By necessity, a Mars sample return mission must sample the upper few meters of the Martian surface. This material was subjected to a wide variety of physical processes. Presently, the most important processes are believed to be wind-driven erosion and deposition, and water ice accumulation at higher latitudes. A sample return mission represents an opportunity to better understand and quantify these important geological processes. By obtaining sample cores at key locations, it may be possible to interpret much of recent Martian climatic history.

  14. Return-volatility correlation in financial dynamics.

    PubMed

    Qiu, T; Zheng, B; Ren, F; Trimper, S

    2006-06-01

    We investigate the return-volatility correlation both local and nonlocal in time with daily and minutely data of the German DAX and Chinese indices, and observe a leverage effect for the German DAX, while an antileverage effect for the Chinese indices. In the negative time direction, i.e., for the volatility-return correlation, an antileverage effect nonlocal in time is detected for both the German DAX and Chinese indices, although the duplicate local in time does not exist. A retarded volatility model may describe the asymmetric properties of the financial indices in the positive time direction.

  15. Return-volatility correlation in financial dynamics

    NASA Astrophysics Data System (ADS)

    Qiu, T.; Zheng, B.; Ren, F.; Trimper, S.

    2006-06-01

    We investigate the return-volatility correlation both local and nonlocal in time with daily and minutely data of the German DAX and Chinese indices, and observe a leverage effect for the German DAX, while an antileverage effect for the Chinese indices. In the negative time direction, i.e., for the volatility-return correlation, an antileverage effect nonlocal in time is detected for both the German DAX and Chinese indices, although the duplicate local in time does not exist. A retarded volatility model may describe the asymmetric properties of the financial indices in the positive time direction.

  16. Horizontal fields generated by return strokes

    NASA Technical Reports Server (NTRS)

    Cooray, Vernon

    1991-01-01

    Horizontal fields generated by return strokes play an important role in the interaction of lightning generated electric fields with power lines. In many of the recent investigations on the interaction of lightning electromagnetic fields with power lines, the horizontal field was calculated by employing the expression for the tilt of the electric field of a plane wave propagating over finitely conducting earth. The method is suitable for calculating horizontal fields generated by return strokes at distances as close as 200m. At these close ranges, the use of the wavetilt expression can cause large errors.

  17. 7 CFR 3560.305 - Return on investment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Return on investment. 3560.305 Section 3560.305... AGRICULTURE DIRECT MULTI-FAMILY HOUSING LOANS AND GRANTS Financial Management § 3560.305 Return on investment. (a) Borrower's return on investment. Borrowers may receive a return on their investment (ROI)...

  18. 26 CFR 1.6013-1 - Joint returns.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 13 2012-04-01 2012-04-01 false Joint returns. 1.6013-1 Section 1.6013-1...) INCOME TAXES (CONTINUED) Tax Returns Or Statements § 1.6013-1 Joint returns. (a) In general. (1) A husband and wife may elect to make a joint return under section 6013(a) even though one of the spouses...

  19. 26 CFR 1.6013-1 - Joint returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 13 2013-04-01 2013-04-01 false Joint returns. 1.6013-1 Section 1.6013-1...) INCOME TAXES (CONTINUED) Tax Returns Or Statements § 1.6013-1 Joint returns. (a) In general. (1) A husband and wife may elect to make a joint return under section 6013(a) even though one of the spouses...

  20. 26 CFR 1.6013-1 - Joint returns.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 13 2014-04-01 2014-04-01 false Joint returns. 1.6013-1 Section 1.6013-1...) INCOME TAXES (CONTINUED) Tax Returns Or Statements § 1.6013-1 Joint returns. (a) In general. (1) A husband and wife may elect to make a joint return under section 6013(a) even though one of the spouses...

  1. 26 CFR 1.6013-1 - Joint returns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 13 2010-04-01 2010-04-01 false Joint returns. 1.6013-1 Section 1.6013-1...) INCOME TAXES Tax Returns Or Statements § 1.6013-1 Joint returns. (a) In general. (1) A husband and wife may elect to make a joint return under section 6013(a) even though one of the spouses has no...

  2. 26 CFR 1.6013-1 - Joint returns.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 13 2011-04-01 2011-04-01 false Joint returns. 1.6013-1 Section 1.6013-1...) INCOME TAXES (CONTINUED) Tax Returns Or Statements § 1.6013-1 Joint returns. (a) In general. (1) A husband and wife may elect to make a joint return under section 6013(a) even though one of the spouses...

  3. 27 CFR 479.51 - Fraudulent return.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2012-04-01 2010-04-01 true Fraudulent return. 479.51 Section 479.51 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES, AND...

  4. 27 CFR 479.51 - Fraudulent return.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Fraudulent return. 479.51 Section 479.51 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES, AND...

  5. 27 CFR 479.51 - Fraudulent return.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2013-04-01 2013-04-01 false Fraudulent return. 479.51 Section 479.51 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES, AND...

  6. 27 CFR 479.51 - Fraudulent return.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2011-04-01 2010-04-01 true Fraudulent return. 479.51 Section 479.51 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES, AND...

  7. 27 CFR 479.51 - Fraudulent return.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2014-04-01 2014-04-01 false Fraudulent return. 479.51 Section 479.51 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES, AND...

  8. Tortuosity of lightning return stroke channels

    NASA Technical Reports Server (NTRS)

    Levine, D. M.; Gilson, B.

    1984-01-01

    Data obtained from photographs of lightning are presented on the tortuosity of return stroke channels. The data were obtained by making piecewise linear fits to the channels, and recording the cartesian coordinates of the ends of each linear segment. The mean change between ends of the segments was nearly zero in the horizontal direction and was about eight meters in the vertical direction. Histograms of these changes are presented. These data were used to create model lightning channels and to predict the electric fields radiated during return strokes. This was done using a computer generated random walk in which linear segments were placed end-to-end to form a piecewise linear representation of the channel. The computer selected random numbers for the ends of the segments assuming a normal distribution with the measured statistics. Once the channels were simulated, the electric fields radiated during a return stroke were predicted using a transmission line model on each segment. It was found that realistic channels are obtained with this procedure, but only if the model includes two scales of tortuosity: fine scale irregularities corresponding to the local channel tortuosity which are superimposed on large scale horizontal drifts. The two scales of tortuosity are also necessary to obtain agreement between the electric fields computed mathematically from the simulated channels and the electric fields radiated from real return strokes. Without large scale drifts, the computed electric fields do not have the undulations characteristics of the data.

  9. Early Learning: Return on Investment. Annotated Bibliography

    ERIC Educational Resources Information Center

    Hite, Jenny

    2014-01-01

    Today's researchers seek to determine if contemporary pre-K programs provide the strong return on investment found by researchers in the 1960's High/Scope Perry Preschool Program and 1970's North Carolina Abecedarian Project. Research then showed that these two programs created positive academic effects that accompanied their students as they…

  10. An Organization's Economic Return on Training Investment.

    ERIC Educational Resources Information Center

    Pucel, David J.; Lyau, Nyan-Myau

    A study examined the relationship between investment in training and labor productivity in a sample of 237 large and medium-size Taiwanese firms producing auto parts. Of the 162 firms (68.4%) that returned usable questionnaires, 142 (59.9%) had training programs and 131 (55.3%) provided full cost data. The data were analyzed by multiple regression…

  11. NASA returns rocks from a comet.

    PubMed

    Burnett, Don S

    2006-12-15

    Cometary particles returned by the Stardust Discovery Mission are primarily silicate materials of solar system origin. Some of the grains were formed at high temperatures close to the Sun, but then transported far out to the Kuiper belt region of the solar system before being incorporated in the comet.

  12. A Sample Return Container with Hermetic Seal

    NASA Technical Reports Server (NTRS)

    Kong, Kin Yuen; Rafeek, Shaheed; Sadick, Shazad; Porter, Christopher C.

    2000-01-01

    A sample return container is being developed by Honeybee Robotics to receive samples from a derivative of the Champollion/ST4 Sample Acquisition and Transfer Mechanism or other samplers and then hermetically seal samples for a sample return mission. The container is enclosed in a phase change material (PCM) chamber to prevent phase change during return and re-entry to earth. This container is designed to operate passively with no motors and actuators. Using the sampler's featured drill tip for interfacing, transfer-ring and sealing samples, the container consumes no electrical power and therefore minimizes sample temperature change. The circular container houses a few isolated canisters, which will be sealed individually for samples acquired from different sites or depths. The drill based sampler indexes each canister to the sample transfer position, below the index interface for sample transfer. After sample transfer is completed, the sampler indexes a seal carrier, which lines up seals with the openings of the canisters. The sampler moves to the sealing interface and seals the sample canisters one by one. The sealing interface can be designed to work with C-seals, knife edge seals and cup seals. Again, the sampler provides all sealing actuation. This sample return container and co-engineered sample acquisition system are being developed by Honeybee Robotics in collaboration with the JPL Exploration Technology program.

  13. Galahad: medium class asteroid sample return mission

    NASA Astrophysics Data System (ADS)

    Cheng, Andrew; Rivkin, Andrew; Adler, Mark

    The Galahad asteroid sample return mission proposal to the NASA New Frontiers solicitation met all of the objectives for the Asteroid Rover/Sample Return mission as defined in that announcement. Galahad is in many ways similar to the Marco Polo and the OSIRIS-Rex proposals. All three missions plan bulk sample returns from primitive, C or B class Near Earth asteroids. Galahad in particular will rendezvous with and orbit the binary C-asteroid 1996 FG3, making extensive orbital measurements. It will then land and collect over 60 g of well-documented samples with geologic context for return to Earth. The samples are expected to provide abundant materials from the early solar system, including chondrules and CAIs, as well as a primitive assemblage of organics, presolar grains and probably hydrated minerals. Analyses of these samples will yield new understanding of the early solar system, planetary accretion, and the nature and origins of prebiotic organic material. We will discuss scientific and technical approaches to characterization of, landing on, and sample collection from small primitive bodies.

  14. Enterprise Return on a Training Investment.

    ERIC Educational Resources Information Center

    Doucouliagos, Chris; Sgro, Pasquale

    The return on investment (ROI) obtained by enterprises that invest in training was examined through case studies of seven Australian work organizations. The case study organizations included a government-owned transportation company, a privately owned company, a major nongovernmental charitable organization, a publicly listed corporation, and two…

  15. The 80's--Return to Traditions.

    ERIC Educational Resources Information Center

    Deloria, Vine, Jr.

    Indians should be the ones to determine Indian education policy. Local control and freedom from outside interference would be the best thing for Indian education all around. Policymakers must first realize that education, if it is to be relevant to American Indians, must return in both content and substance to Indian traditions. Rather than…

  16. Near-Earth Asteroid Sample Return Missions

    NASA Technical Reports Server (NTRS)

    Sears, D. W. G.; Allen, C. C.; Britt, D. T.; Brownlee, D. E.; Cheng, A.; Chapman, C. R.; Clark, B. C.; Drake, B. G.; Franchi, I. A.; Gorevan, S.

    2001-01-01

    The rate of discovery of new Near Earth Asteroids (NEAs) and the success of D-S 1 and NEAR-Shoemaker, suggest that sample return from NEAs is now technically feasible. Here we present a summary of a recent workshop on the topic. Additional information is contained in the original extended abstract.

  17. Return Migration to Mexico: Does Health Matter?

    PubMed Central

    Arenas, Erika; Goldman, Noreen; Pebley, Anne R.; Teruel, Graciela

    2015-01-01

    We use data from three rounds of the Mexican Family Life Survey to examine whether migrants in the United States returning to Mexico in the period 2005–2012 have worse health than those remaining in the United States. Despite extensive interest by demographers in health-related selection, this has been a neglected area of study in the literature on U.S.-Mexico migration, and the few results to date have been contradictory and inconclusive. Using five self-reported health variables collected while migrants resided in the United States and subsequent migration history, we find direct evidence of higher probabilities of return migration for Mexican migrants in poor health as well as lower probabilities of return for migrants with improving health. These findings are robust to the inclusion of potential confounders reflecting the migrants’ demographic characteristics, economic situation, family ties, and origin and destination characteristics. We anticipate that in the coming decade, health may become an even more salient issue in migrants’ decisions about returning to Mexico, given the recent expansion in access to health insurance in Mexico. PMID:26385111

  18. Exploring Literate Lives: Returning to the Field

    ERIC Educational Resources Information Center

    Henderson, Robyn; Woods, Annette

    2016-01-01

    The challenges of conducting lengthy fieldwork in today's busy academic world have impacted the types of research that are able to be carried out. In particular, traditional educational ethnography has become problematic for research beyond initial doctoral research programs. This article analyzes data collected during a return to the field of a…

  19. Return Migration to Mexico: Does Health Matter?

    PubMed

    Arenas, Erika; Goldman, Noreen; Pebley, Anne R; Teruel, Graciela

    2015-12-01

    We use data from three rounds of the Mexican Family Life Survey to examine whether migrants in the United States returning to Mexico in the period 2005-2012 have worse health than those remaining in the United States. Despite extensive interest by demographers in health-related selection, this has been a neglected area of study in the literature on U.S.-Mexico migration, and the few results to date have been contradictory and inconclusive. Using five self-reported health variables collected while migrants resided in the United States and subsequent migration history, we find direct evidence of higher probabilities of return migration for Mexican migrants in poor health as well as lower probabilities of return for migrants with improving health. These findings are robust to the inclusion of potential confounders reflecting the migrants' demographic characteristics, economic situation, family ties, and origin and destination characteristics. We anticipate that in the coming decade, health may become an even more salient issue in migrants' decisions about returning to Mexico, given the recent expansion in access to health insurance in Mexico.

  20. [Coordination for a successful return home].

    PubMed

    Mamoudy, Claire; Jaulin, Marie; Cerf, Dominique

    2014-01-01

    The organisation of the return home of a dependent person is an important stage in their care. Good coordination between the different healthcare and social professionals enable their needs to be assessed in order for adapted solutions to be offered. In this global approach, the teams take into account not only the patient in their living environment but also their family carer.

  1. Renewal, reform, and return to flight.

    PubMed

    Dorr, Robert F

    2005-06-01

    The Washington Watch column discusses budget issues on Capitol Hill relating to aerospace issues, including the shuttle's delayed return to flight and Michael Griffin becoming the new NASA administrator; the Transportation Security Administration becoming downsized; and new personnel at the Pentagon.

  2. Multivariate Models of Adult Pacific Salmon Returns

    PubMed Central

    Burke, Brian J.; Peterson, William T.; Beckman, Brian R.; Morgan, Cheryl; Daly, Elizabeth A.; Litz, Marisa

    2013-01-01

    Most modeling and statistical approaches encourage simplicity, yet ecological processes are often complex, as they are influenced by numerous dynamic environmental and biological factors. Pacific salmon abundance has been highly variable over the last few decades and most forecasting models have proven inadequate, primarily because of a lack of understanding of the processes affecting variability in survival. Better methods and data for predicting the abundance of returning adults are therefore required to effectively manage the species. We combined 31 distinct indicators of the marine environment collected over an 11-year period into a multivariate analysis to summarize and predict adult spring Chinook salmon returns to the Columbia River in 2012. In addition to forecasts, this tool quantifies the strength of the relationship between various ecological indicators and salmon returns, allowing interpretation of ecosystem processes. The relative importance of indicators varied, but a few trends emerged. Adult returns of spring Chinook salmon were best described using indicators of bottom-up ecological processes such as composition and abundance of zooplankton and fish prey as well as measures of individual fish, such as growth and condition. Local indicators of temperature or coastal upwelling did not contribute as much as large-scale indicators of temperature variability, matching the spatial scale over which salmon spend the majority of their ocean residence. Results suggest that effective management of Pacific salmon requires multiple types of data and that no single indicator can represent the complex early-ocean ecology of salmon. PMID:23326586

  3. Return on Investment in Training: Research Readings.

    ERIC Educational Resources Information Center

    Smith, Andrew, Ed.

    Following an introduction ("Return on Investment in Training" by Andrew Smith) that provides an overview and a synopsis of research findings, the following five chapters of this book present the results of five research projects funded by the National Research and Evaluation Committee in Australia in 1999-2000. The first four of these…

  4. Reality Check: A Teacher Educator Returns Home

    ERIC Educational Resources Information Center

    Scherff, Lisa; Kaplan, Jeff

    2006-01-01

    This collaborative self-study, told through email excerpts and reflections, explores a teacher educator's return to high school teaching. In this study, we juxtapose our voices and alternate between past and present to develop insights that reveal how going back can lead to moving forward with respect to educating prospective teachers. While the…

  5. An Editor's Journey: Return to Haiti

    ERIC Educational Resources Information Center

    Moy, Yvette

    2012-01-01

    This paper recounts the author's story as she returned to Haiti in February to join a building project near Port-Au-Prince and to document efforts by U.S. higher education institutions to help the country rebound from the devastating 2010 earthquake. The author describes how consortiums have been formed in order to support the development of the…

  6. 26 CFR 36.3121(l)(10)-3 - Returns.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 15 2011-04-01 2011-04-01 false Returns. 36.3121(l)(10)-3 Section 36.3121(l)(10....3121(l)(10)-3 Returns. (a) The forms prescribed for use in making returns of the taxes imposed by the... returns of its liability under an agreement entered into as provided in § 36.3121(l)(1)-1. Returns of...

  7. 26 CFR 36.3121(l)(10)-3 - Returns.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 15 2014-04-01 2014-04-01 false Returns. 36.3121(l)(10)-3 Section 36.3121(l)(10....3121(l)(10)-3 Returns. (a) The forms prescribed for use in making returns of the taxes imposed by the... returns of its liability under an agreement entered into as provided in § 36.3121(l)(1)-1. Returns of...

  8. 26 CFR 36.3121(l)(10)-3 - Returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 15 2013-04-01 2013-04-01 false Returns. 36.3121(l)(10)-3 Section 36.3121(l)(10....3121(l)(10)-3 Returns. (a) The forms prescribed for use in making returns of the taxes imposed by the... returns of its liability under an agreement entered into as provided in § 36.3121(l)(1)-1. Returns of...

  9. 26 CFR 36.3121(l)(10)-3 - Returns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 15 2010-04-01 2010-04-01 false Returns. 36.3121(l)(10)-3 Section 36.3121(l)(10....3121(l)(10)-3 Returns. (a) The forms prescribed for use in making returns of the taxes imposed by the... returns of its liability under an agreement entered into as provided in § 36.3121(l)(1)-1. Returns of...

  10. 26 CFR 36.3121(l)(10)-3 - Returns.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 15 2012-04-01 2012-04-01 false Returns. 36.3121(l)(10)-3 Section 36.3121(l)(10....3121(l)(10)-3 Returns. (a) The forms prescribed for use in making returns of the taxes imposed by the... returns of its liability under an agreement entered into as provided in § 36.3121(l)(1)-1. Returns of...

  11. 26 CFR 301.6103(p)(2)(B)-1 - Disclosure of returns and return information by other agencies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... other agencies. 301.6103(p)(2)(B)-1 Section 301.6103(p)(2)(B)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(2)(B)-1 Disclosure of returns and return information... regulations thereunder, including, if applicable, safeguards imposed by section 6103(p)(4). (d) Records...

  12. 26 CFR 301.6103(p)(4)-1 - Procedures relating to safeguards for returns or return information.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... or return information. 301.6103(p)(4)-1 Section 301.6103(p)(4)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(4)-1 Procedures relating to safeguards for returns..., see § 301.6103(p)(7)-1....

  13. 26 CFR 301.6103(n)-1 - Disclosure of returns and return information in connection with written contracts or agreements...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... administration purposes. 301.6103(n)-1 Section 301.6103(n)-1 Internal Revenue INTERNAL REVENUE SERVICE... and Returns Returns and Records § 301.6103(n)-1 Disclosure of returns and return information in... administration purposes. (a) General rule. (1) Pursuant to the provisions of section 6103(n) of the...

  14. 26 CFR 301.6103(n)-1 - Disclosure of returns and return information in connection with written contracts or agreements...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... administration purposes. 301.6103(n)-1 Section 301.6103(n)-1 Internal Revenue INTERNAL REVENUE SERVICE... and Returns Returns and Records § 301.6103(n)-1 Disclosure of returns and return information in... administration purposes. (a) General rule. (1) Pursuant to the provisions of section 6103(n) of the...

  15. 26 CFR 301.6103(n)-1 - Disclosure of returns and return information in connection with written contracts or agreements...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... administration purposes. 301.6103(n)-1 Section 301.6103(n)-1 Internal Revenue INTERNAL REVENUE SERVICE... and Returns Returns and Records § 301.6103(n)-1 Disclosure of returns and return information in... administration purposes. (a) General rule. (1) Pursuant to the provisions of section 6103(n) of the...

  16. 26 CFR 301.6103(n)-1 - Disclosure of returns and return information in connection with written contracts or agreements...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... administration purposes. 301.6103(n)-1 Section 301.6103(n)-1 Internal Revenue INTERNAL REVENUE SERVICE... and Returns Returns and Records § 301.6103(n)-1 Disclosure of returns and return information in... administration purposes. (a) General rule. (1) Pursuant to the provisions of section 6103(n) of the...

  17. 26 CFR 301.6103(p)(4)-1 - Procedures relating to safeguards for returns or return information.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... or return information. 301.6103(p)(4)-1 Section 301.6103(p)(4)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(4)-1 Procedures relating to safeguards for returns..., see § 301.6103(p)(7)-1....

  18. 26 CFR 301.6103(p)(4)-1 - Procedures relating to safeguards for returns or return information.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... or return information. 301.6103(p)(4)-1 Section 301.6103(p)(4)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(4)-1 Procedures relating to safeguards for returns..., see § 301.6103(p)(7)-1....

  19. 26 CFR 301.6103(p)(4)-1 - Procedures relating to safeguards for returns or return information.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... or return information. 301.6103(p)(4)-1 Section 301.6103(p)(4)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(4)-1 Procedures relating to safeguards for returns..., see § 301.6103(p)(7)-1....

  20. 26 CFR 301.6103(p)(4)-1 - Procedures relating to safeguards for returns or return information.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... or return information. 301.6103(p)(4)-1 Section 301.6103(p)(4)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(4)-1 Procedures relating to safeguards for returns..., see § 301.6103(p)(7)-1....

  1. 26 CFR 1.6011-7 - Specified tax return preparers required to file individual income tax returns using magnetic media.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... individual income tax returns using magnetic media. 1.6011-7 Section 1.6011-7 Internal Revenue INTERNAL... tax returns using magnetic media. Individual income tax returns that are required to be filed on magnetic media by tax return preparers under section 6011(e)(3) and § 301.6011-7 of this chapter must...

  2. 26 CFR 301.6103(l)-1 - Disclosure of returns and return information for purposes other than tax administration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... for purposes other than tax administration. 301.6103(l)-1 Section 301.6103(l)-1 Internal Revenue... ADMINISTRATION Information and Returns Returns and Records § 301.6103(l)-1 Disclosure of returns and return... provisions of section 6103(l) of the Internal Revenue Code, the term agent includes a contractor....

  3. 26 CFR 301.6103(l)-1 - Disclosure of returns and return information for purposes other than tax administration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... for purposes other than tax administration. 301.6103(l)-1 Section 301.6103(l)-1 Internal Revenue... ADMINISTRATION Information and Returns Returns and Records § 301.6103(l)-1 Disclosure of returns and return... provisions of section 6103(l) of the Internal Revenue Code, the term agent includes a contractor....

  4. 26 CFR 301.6103(l)-1 - Disclosure of returns and return information for purposes other than tax administration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... for purposes other than tax administration. 301.6103(l)-1 Section 301.6103(l)-1 Internal Revenue... ADMINISTRATION Information and Returns Returns and Records § 301.6103(l)-1 Disclosure of returns and return... provisions of section 6103(l) of the Internal Revenue Code, the term agent includes a contractor....

  5. 26 CFR 301.6103(l)-1 - Disclosure of returns and return information for purposes other than tax administration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... for purposes other than tax administration. 301.6103(l)-1 Section 301.6103(l)-1 Internal Revenue... ADMINISTRATION Information and Returns Returns and Records § 301.6103(l)-1 Disclosure of returns and return... provisions of section 6103(l) of the Internal Revenue Code, the term agent includes a contractor....

  6. 26 CFR 301.6103(l)-1 - Disclosure of returns and return information for purposes other than tax administration.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... for purposes other than tax administration. 301.6103(l)-1 Section 301.6103(l)-1 Internal Revenue... ADMINISTRATION Information and Returns Returns and Records § 301.6103(l)-1 Disclosure of returns and return... provisions of section 6103(l) of the Internal Revenue Code, the term agent includes a contractor....

  7. 26 CFR 1.6011-7 - Specified tax return preparers required to file individual income tax returns using magnetic media.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... individual income tax returns using magnetic media. 1.6011-7 Section 1.6011-7 Internal Revenue INTERNAL... tax returns using magnetic media. Individual income tax returns that are required to be filed on magnetic media by tax return preparers under section 6011(e)(3) and § 301.6011-7 of this chapter must...

  8. 26 CFR 1.6011-7 - Specified tax return preparers required to file individual income tax returns using magnetic media.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... individual income tax returns using magnetic media. 1.6011-7 Section 1.6011-7 Internal Revenue INTERNAL... tax returns using magnetic media. Individual income tax returns that are required to be filed on magnetic media by tax return preparers under section 6011(e)(3) and § 301.6011-7 of this chapter must...

  9. 26 CFR 301.6033-4 - Required use of magnetic media for returns by organizations required to file returns under...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 18 2012-04-01 2012-04-01 false Required use of magnetic media for returns by... ADMINISTRATION Information and Returns Returns and Records § 301.6033-4 Required use of magnetic media for... required to file returns under section 6033 on magnetic media. An organization required to file a...

  10. 26 CFR 1.6011-7 - Specified tax return preparers required to file individual income tax returns using magnetic media.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... individual income tax returns using magnetic media. 1.6011-7 Section 1.6011-7 Internal Revenue INTERNAL... tax returns using magnetic media. Individual income tax returns that are required to be filed on magnetic media by tax return preparers under section 6011(e)(3) and § 301.6011-7 of this chapter must...

  11. 26 CFR 301.6033-4 - Required use of magnetic media for returns by organizations required to file returns under...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 18 2014-04-01 2014-04-01 false Required use of magnetic media for returns by... ADMINISTRATION Information and Returns Returns and Records § 301.6033-4 Required use of magnetic media for... required to file returns under section 6033 on magnetic media. An organization required to file a...

  12. 26 CFR 301.6033-4 - Required use of magnetic media for returns by organizations required to file returns under...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 18 2013-04-01 2013-04-01 false Required use of magnetic media for returns by... ADMINISTRATION Information and Returns Returns and Records § 301.6033-4 Required use of magnetic media for... required to file returns under section 6033 on magnetic media. An organization required to file a...

  13. 26 CFR 301.6103(p)(2)(B)-1 - Disclosure of returns and return information by other agencies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... other agencies. 301.6103(p)(2)(B)-1 Section 301.6103(p)(2)(B)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(2)(B)-1 Disclosure of returns and return information by other agencies. (a) General rule. Subject to the requirements of paragraphs (b), (c), and (d)...

  14. 26 CFR 301.6103(p)(2)(B)-1 - Disclosure of returns and return information by other agencies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... other agencies. 301.6103(p)(2)(B)-1 Section 301.6103(p)(2)(B)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(2)(B)-1 Disclosure of returns and return information by other agencies. (a) General rule. Subject to the requirements of paragraphs (b), (c), and (d)...

  15. 26 CFR 301.6103(p)(2)(B)-1 - Disclosure of returns and return information by other agencies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... other agencies. 301.6103(p)(2)(B)-1 Section 301.6103(p)(2)(B)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(2)(B)-1 Disclosure of returns and return information by other agencies. (a) General rule. Subject to the requirements of paragraphs (b), (c), and (d)...

  16. 26 CFR 301.6103(p)(2)(B)-1 - Disclosure of returns and return information by other agencies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... other agencies. 301.6103(p)(2)(B)-1 Section 301.6103(p)(2)(B)-1 Internal Revenue INTERNAL REVENUE... Information and Returns Returns and Records § 301.6103(p)(2)(B)-1 Disclosure of returns and return information by other agencies. (a) General rule. Subject to the requirements of paragraphs (b), (c), and (d)...

  17. 26 CFR 301.6103(n)-1 - Disclosure of returns and return information in connection with written contracts or agreements...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... administration purposes. 301.6103(n)-1 Section 301.6103(n)-1 Internal Revenue INTERNAL REVENUE SERVICE... and Returns Returns and Records § 301.6103(n)-1 Disclosure of returns and return information in... administration purposes. (a) General rule. (1) Pursuant to the provisions of section 6103(n) of the...

  18. The effect that energy storage and return feet have on the propulsion of the body: a pilot study.

    PubMed

    Crimin, Anthony; McGarry, Anthony; Harris, Elena Jane; Solomonidis, Stephan Emanuel

    2014-09-01

    A variety of energy storage and return prosthetic feet are currently available for use within lower limb prostheses. Designs claim to provide a beneficial energy return during push-off, but the extent to which this occurs remains disputed. Techniques currently used to measure energy storage, dissipation and return within the structure of the prosthetic foot are debatable, with limited evidence to support substantial elastic energy storage and return from existing designs. The aim of this study was to evaluate the performance of energy storage and return foot designs through considering the ankle power during push-off and the effect on body centre of mass propulsion. To achieve this aim, the gait patterns of six trans-tibial prosthetic users wearing different designs of energy storage and return feet were analysed while ascending a ramp. Three examples of energy storage and return feet (suitable for moderate activity) were selected and randomly evaluated: the Blatchford's Epirus, Össur Assure and College Park Tribute feet. The power at the anatomical and mechanical ankle joints was integrated to evaluate the work done over the gait cycle. The direction of the inertial force, and therefore propulsion of the body centre of mass, was used to indicate the effect of the energy return by the energy storage and return feet. Results indicate that although energy storage and return feet may provide energy return, the work done around the prosthetic ankle indicates net power absorption. Therefore, the prosthetic limb is unable to contribute to the body centre of mass propulsion to the same extent as the biological limb.

  19. Return to physical activity after gastrocnemius recession

    PubMed Central

    Tang Qian Ying, Camelia; Lai Wei Hong, Sean; Lee, Bing Howe; Thevendran, Gowreeson

    2016-01-01

    AIM To prospectively investigate the time taken and patients’ ability to resume preoperative level of physical activity after gastrocnemius recession. METHODS Endoscopic gastrocnemius recession (EGR) was performed on 48 feet in 46 consecutive sportspersons, with a minimum follow-up of 24 mo. The Halasi Ankle Activity Score was used to quantify the level of physical activity. Time taken to return to work and physical activity was recorded. Functional outcomes were evaluated using the short form 36 (SF-36), American Orthopedic Foot and Ankle Society (AOFAS) Hindfoot score and modified Olerud and Molander (O and M) scores respectively. Patient’s satisfaction and pain experienced were assessed using a modified Likert scale and visual analogue scales. P-value < 0.05 was considered statistically significant. RESULTS Ninety-one percent (n = 42) of all patients returned to their preoperative level of physical activity after EGR. The mean time for return to physical activity was 7.5 (2-24) mo. Ninety-eight percent (n = 45) of all patients were able to return to their preoperative employment status, with a mean time of 3.6 (1-12) mo. Ninety-six percent (n = 23) of all patients with an activity score > 2 were able to resume their preoperative level of physical activity in mean time of 8.8 mo, as compared to 86% (n = 19) of patients whose activity score was ≤ 2, with mean time of 6.1 mo. Significant improvements were noted in SF-36, AOFAS hindfoot and modified O and M scores. Ninety percent of all patients rated good or very good outcomes on the Likert scale. CONCLUSION The majority of patients were able to return to their pre-operative level of sporting activity after EGR. PMID:27900272

  20. Planetary Protection for LIFE-Sample Return from Enceladus

    NASA Astrophysics Data System (ADS)

    Tsou, Peter; Yano, Hajime; Takano, Yoshinori; McKay, David; Takai, Ken; Anbar, Ariel; Baross, J.

    ]. Current Plan: At the 1st flyby of Enceladus at high plume altitude (~150 km), we would survey the status of the plume and jets by making in situ measurements of the gas and dust densities, compositions, and velocities. We would also collect solid ice/volatile samples based upon prior ground planning. The 2nd and final flyby (determined via optimal trajectory from the 1st flyby) will be conducted at low altitude (~20 km), and would perform in situ measurements and collect solid ice and volatile samples. During the 5 year return cruise, we would maintain the samples in their captured state (frozen) under desiccating conditions of low temperature and pressure. After a direct Earth reentry, we would transport the frozen samples from the sample return capsule into a sealed sample transport container, which would then be transported to a higher Biosafety Level (BSL) facility from JAMSTEC (Japan Agency for Marine-Earth Science and Technology) for sample return capsule de-integration and sample distribution. Planetary Protection: Several options for sample return have been conceived and some even demonstrated on previous flight missions (STARDUST, Genesis and Hayabusa). To date, a flight qualified sample containment system does not exist in the US, and it would be cost prohibitive to flight-qualify such a system for use by LIFE under a Discovery Program. Harsh sterilization of the samples would destroy valuable molecular information, defeating the very purpose of returning samples to assess the habitability of Enceladus. The LIFE team has found a viable approach by teaming with JAXA/ISAS. Their Hayabusa II sample containment is a third generation device that can be further improved to meet these NASA and COSPAR planetary protection requirements in an Integrated Sample Subsystem for LIFE. Another aspect of LIFE is the initial de-integration and certification of the returned samples in a higher BSL facility. JAMSTEC is the world’s leading oceanography organization. They are

  1. Current sensor

    DOEpatents

    Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

    2007-01-16

    A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.

  2. 76 FR 22611 - Specified Tax Return Preparers Required To File Individual Income Tax Returns Using Magnetic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-22

    ... Individual Income Tax Returns Using Magnetic Media; Correction AGENCY: Internal Revenue Service (IRS... using magnetic media pursuant to section 6011(e)(3) of the Internal Revenue Code. DATES: This...

  3. Visual cortex responses to suprachoroidal electrical stimulation of the retina: effects of electrode return configuration.

    PubMed

    Cicione, Rosemary; Shivdasani, Mohit N; Fallon, James B; Luu, Chi D; Allen, Penny J; Rathbone, Graeme D; Shepherd, Robert K; Williams, Chris E

    2012-06-01

    A clinically effective retinal prosthesis must evoke localized phosphenes in a retinotopic manner in response to stimulation of each of the retinal electrodes, evoke brightness cues over a wide dynamic range and function within safe stimulus limits. The effects of varying return configuration for retinal stimulation are currently unknown. To investigate this, we implanted a flexible, 7 × 12 electrode array into the suprachoroidal space of normally-sighted, anesthetized cats. Multi-unit activity in the primary visual cortex was recorded in response to electrical stimulation using various return configurations: monopolar vitreous (MPV), common ground (CG), hexagonal (HX), monopolar remote (MPR) and bipolar (BP_N). MPV stimulation was found to be the most charge efficient and was most likely to induce cortical activity within safe charge limits. HX and CG stimulation were found to exhibit greater retinal selectivity compared to the MPV return at the expense of lower cortical yield and higher P50 charge levels, while cortical selectivity was unaffected by choice of return. Responses using MPR and widely spaced BP_N configurations were similar to those using the MPV return. These results suggest that choice of return configuration for a retinal prosthesis will be balanced between resolution and stimulation within safe charge limits.

  4. Return period adjustment for runoff coefficients based on analysis in undeveloped Texas watersheds

    USGS Publications Warehouse

    Dhakal, Nirajan; Fang, Xing; Asquith, William H.; Cleveland, Theodore G.; Thompson, David B.

    2013-01-01

    The rational method for peak discharge (Qp) estimation was introduced in the 1880s. The runoff coefficient (C) is a key parameter for the rational method that has an implicit meaning of rate proportionality, and the C has been declared a function of the annual return period by various researchers. Rate-based runoff coefficients as a function of the return period, C(T), were determined for 36 undeveloped watersheds in Texas using peak discharge frequency from previously published regional regression equations and rainfall intensity frequency for return periods T of 2, 5, 10, 25, 50, and 100 years. The C(T) values and return period adjustments C(T)/C(T=10  year) determined in this study are most applicable to undeveloped watersheds. The return period adjustments determined for the Texas watersheds in this study and those extracted from prior studies of non-Texas data exceed values from well-known literature such as design manuals and textbooks. Most importantly, the return period adjustments exceed values currently recognized in Texas Department of Transportation design guidance when T>10  years.

  5. A Reliable Earth Return System for Safe Recovery of Mars Samples

    NASA Technical Reports Server (NTRS)

    Braun, R.; Killough, B.; Mitcheltree, R.; Carroll, C.

    2000-01-01

    The objective of a Mars sample return mission is to bring selected Mars surface materials to Earth. Numerous approaches for the Earth-return segment have been analyzed including propulsive or aerocapture return to low-Earth orbit followed by Space Shuttle rendezvous and direct entry. Of these approaches, ballistic entry of a small capsule terminating in a ground landing has been shown to be the lowest risk strategy. Over the past two years, significant work has been performed towards development of a robust direct entry vehicle for Mars sample return. In June 1999, the NASA Planetary Protection Officer provided initial guidance to the former Mars Sample Return Project. The sample return phase of the mission was assigned a restricted Earth return planetary protection classification. The draft mission requirement states that the total mean probability of release of unsterilized Mars material into the Earth;s biosphere must be less than 1.0E-06 (1 in a million). This strict requirement drives the approach and design of the Earth return system. To meet this requirement, selection of the Earth return strategy and development of the Earth return system must be guided by risk, not performance, based decisions. An initial Probabilistic Risk Assessment (PRA) was performed to address the direct entry Earth return system containment assurance reliability and to identify high-risk elements of this system. The results of this PRA identified risk elements that include thermal protection system performance during entry, spin-eject orientation and aerodynamic stability during entry, structural integrity under atmospheric deceleration and impact loads, and tracking/recovery of this system. This initial probabilistic risk quantification demonstrates that, with the proper development program, a prototypical direct entry design can satisfy the containment assurance reliability requirement. Through the current Mars Sample Return Advanced Technology Development effort, an extensive

  6. The Global Statistics of Return Times: Return Time Dimensions Versus Generalized Measure Dimensions

    NASA Astrophysics Data System (ADS)

    Mantica, Giorgio

    2010-03-01

    We investigate return times in dynamical systems, i.e. the time required by a trajectory to complete a return journey to a neighborhood of the initial position. In particular, we study the relations holding between the scaling exponents of phase-space moments of return times in balls of diminishing radius, on the one side, and the generalized dimensions of invariant measures, on the other. Because of a heuristic use of Kac theorem, the former have been used in place of the latter in numerical and experimental investigations: to mark the distinction, we call them return time dimensions. We derive a full set of inequalities linking generalized dimensions of invariant measures and return time dimensions. We comment on their optimality with the aid of two maps due to von Neumann-Kakutani and to Gaspard-Wang. We conjecture a formula for the return time dimensions in a typical system. We only assume that the dynamical system under investigation is ergodic and that motion takes place in a compact, finite dimensional space.

  7. Near-Earth Asteroid Returned Sample (NEARS)

    NASA Technical Reports Server (NTRS)

    Shoemaker, Eugene M.; Cheng, Andrew F.

    1994-01-01

    The concept of the Near-Earth Asteroid Returned Sample (NEARS) mission is to return to Earth 10-100 g from each of four to six sites on a near-Earth asteroid and to perform global characterization of the asteroid and measure mass, volume, and density to ten percent. The target asteroid for the mission is 4660 Nereus, probably a primitive C-type asteroid, with the alternate target being 1989ML, an extremely accessible asteroid of unknown type. Launch dates will be 1998, 2000, 2002, and 2004 on the Delta II-7925 launch vehicle. The mission objectives are three-fold. (1) Provide first direct and detailed petrological, chemical, age, and isotopic characterization of a near-Earth asteroid and relate it to terrestrial, lunar, and meteoritic materials. (2) Sample the asteroid regolith and characterize any exotic fragments. (3) Identify heterogeneity in the asteroid's isotopic properties, age, and elemental chemistry.

  8. Organic Contamination Standards for Mars Sample Return

    NASA Astrophysics Data System (ADS)

    Pugel, D. E.; Conley, Catharine

    Collecting samples from Mars and bringing them to Earth for study has long been an objective of planetary exploration, among other reasons because this allows for the application of the most sensitive instruments to detect biosignatures and other indications of possible Mars life. Understanding terrestrial contamination that could be introduced into Mars samples and confound life detection measurements is an essential aspect of the investigative process. Defining quantitative limits on terrestrial organic contamination is necessary for planetary protection purposes, to ensure high confidence in a putative detection of `Mars life' or possible biohazards in samples after return to Earth. As reported here, NASA's Office of Planetary Protection is initiating a process to establish appropriate limits and controls on organic contamination introduced into Mars samples that will be collected and cached by the Mars 2020 mission for possible future return to Earth.

  9. STARDUST: Finessing expensive cometary sample returns

    NASA Astrophysics Data System (ADS)

    Brownlee, Donald E.; Tsou, Peter; Atkins, Kenneth L.; Yen, Chen-wan; Vellinga, Joseph M.; Price, Stephen; Benton Clark, C.

    1996-07-01

    The STARDUST Discovery mission will collect samples of cometary coma and interstellar dust and return them to Earth. Five years after launch in February 1999, coma dust in the 1- to 100-μm size range will be captured by impact into ultra-low-density silica aerogel during a 6 kms -1 flyby of Comet Wild 2. The returned samples will be investigated at laboratories where the most critical information on these primitive materials is retained. The Jet Propulsion Laboratory will provide project management with Lockheed Martin Astronautics as the spacecraft industrial partner STARDUST management will aggressively and innovatively achieve cost control through the use of Total Quality Management principles, the chief of which will be organization in a Project Engineering and Integration Team that "flattens" the traditional hierarchical structure by including all project elements from the beginning, in a concurrent engineering framework focusing on evolving Integrated Mission Capability

  10. Returners and explorers dichotomy in human mobility

    NASA Astrophysics Data System (ADS)

    Pappalardo, Luca; Simini, Filippo; Rinzivillo, Salvatore; Pedreschi, Dino; Giannotti, Fosca; Barabási, Albert-László

    2015-09-01

    The availability of massive digital traces of human whereabouts has offered a series of novel insights on the quantitative patterns characterizing human mobility. In particular, numerous recent studies have lead to an unexpected consensus: the considerable variability in the characteristic travelled distance of individuals coexists with a high degree of predictability of their future locations. Here we shed light on this surprising coexistence by systematically investigating the impact of recurrent mobility on the characteristic distance travelled by individuals. Using both mobile phone and GPS data, we discover the existence of two distinct classes of individuals: returners and explorers. As existing models of human mobility cannot explain the existence of these two classes, we develop more realistic models able to capture the empirical findings. Finally, we show that returners and explorers play a distinct quantifiable role in spreading phenomena and that a correlation exists between their mobility patterns and social interactions.

  11. Returners and explorers dichotomy in human mobility.

    PubMed

    Pappalardo, Luca; Simini, Filippo; Rinzivillo, Salvatore; Pedreschi, Dino; Giannotti, Fosca; Barabási, Albert-László

    2015-09-08

    The availability of massive digital traces of human whereabouts has offered a series of novel insights on the quantitative patterns characterizing human mobility. In particular, numerous recent studies have lead to an unexpected consensus: the considerable variability in the characteristic travelled distance of individuals coexists with a high degree of predictability of their future locations. Here we shed light on this surprising coexistence by systematically investigating the impact of recurrent mobility on the characteristic distance travelled by individuals. Using both mobile phone and GPS data, we discover the existence of two distinct classes of individuals: returners and explorers. As existing models of human mobility cannot explain the existence of these two classes, we develop more realistic models able to capture the empirical findings. Finally, we show that returners and explorers play a distinct quantifiable role in spreading phenomena and that a correlation exists between their mobility patterns and social interactions.

  12. Returners and explorers dichotomy in human mobility

    PubMed Central

    Pappalardo, Luca; Simini, Filippo; Rinzivillo, Salvatore; Pedreschi, Dino; Giannotti, Fosca; Barabási, Albert-László

    2015-01-01

    The availability of massive digital traces of human whereabouts has offered a series of novel insights on the quantitative patterns characterizing human mobility. In particular, numerous recent studies have lead to an unexpected consensus: the considerable variability in the characteristic travelled distance of individuals coexists with a high degree of predictability of their future locations. Here we shed light on this surprising coexistence by systematically investigating the impact of recurrent mobility on the characteristic distance travelled by individuals. Using both mobile phone and GPS data, we discover the existence of two distinct classes of individuals: returners and explorers. As existing models of human mobility cannot explain the existence of these two classes, we develop more realistic models able to capture the empirical findings. Finally, we show that returners and explorers play a distinct quantifiable role in spreading phenomena and that a correlation exists between their mobility patterns and social interactions. PMID:26349016

  13. Near-Earth Asteroid Sample Return Workshop

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This volume contains abstracts that have been accepted for presentation at the Near-Earth Asteroid Sample Return Workshop, 11-12 Dec 2000. The Steering Committee consisted of Derek Sears, Chair, Dan Britt, Don Brownlee, Andrew Cheng, Benton Clark, Leon Gefert, Steve Gorevan, Marilyn Lindstrom, Carle Pieters, Jeff Preble, Brian Wilcox, and Don Yeomans. Logistical, administrative, and publications support were provided by the Publications and Program Services Department of the Lunar and Planetary Institute.

  14. Isotopic studies in returned lunar samples

    NASA Technical Reports Server (NTRS)

    Alexander, E. C., Jr.

    1971-01-01

    Analysis of lunar soil samples returned by Apollo 11 and 12 flights are discussed. Isotopic studies of the rare gases from Apollo 11 flight lunar samples are presented. The lunar soil analyses indicated the following: (1) high concentrations of solar wind rare gases, (2) isotopic match between solar wind gases and gas components in gas-rich meteorites, and (3) rare gases attributable to spallation reactions induced in heavier nuclides by cosmic ray particles.

  15. Environmental water incentive policy and return flows

    NASA Astrophysics Data System (ADS)

    Qureshi, M. E.; Schwabe, K.; Connor, J.; Kirby, M.

    2010-04-01

    With increasing urban, industrial, and agricultural water demand and projected reduced supply under climate change, allocations to the environment are critically low in many arid and semiarid basins. Consequently, many governments are striving to augment environmental flows, often through market-oriented mechanisms that involve compensating irrigated agriculture, the largest water user in most basins, for reducing diversions. A widely documented challenge with policies to recover water for the environment arises because part of the water diversion reduction can form the basis for downstream consumptive water rights or environmental flows. This article gives an empirical comparison of two incentive policies to acquire water for environmental flows for a part of the Murray-Darling Basin (MDB), Australia. One policy consists of paying irrigators and water delivery firms to make capital and management investments that improve on-farm irrigation and water-conveyance; the other policy consists of having the government buy water from irrigators on the active MDB water market. The results show that the first option results in relatively larger return flow reduction, while the second option tends to induce significant irrigated land retirement with relatively large reductions in consumptive use and small reductions in return flow. In cases where irrigation losses result in little useful return flow (e.g., evaporative loss reduction or during drought in some instances), efficiency-improving investments may provide some cost-effective opportunities. Where a large portion of loss forms valuable return flow, it is difficult to make a case for the cost-effectiveness of policies involving payments for investments in irrigation and conveyance system upgrades.

  16. Horizontal electric fields from lightning return strokes

    NASA Technical Reports Server (NTRS)

    Thomson, E. M.; Medelius, P. J.; Rubinstein, M.; Uman, M. A.; Johnson, J.

    1988-01-01

    An experiment to measure simultaneously the wideband horizontal and vertical electric fields from lightning return strokes is described. Typical wave shapes of the measured horizontal and vertical fields are presented, and the horizontal fields are characterized. The measured horizontal fields are compared with calculated horizontal fields obtained by applying the wavetilt formula to the vertical fields. The limitations and sources of error in the measurement technique are discussed.

  17. Edward Teller Returns to LOS Alamos

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.

    2010-01-01

    I was asked to share some reflections of Edward Teller's return to Los Alamos during my directorship. I met Teller late in his life. My comments focus on that time and they will be mostly in the form of stories of my interactions and those of my colleagues with Teller. Although the focus of this symposium is on Teller's contributions to science, at Los Alamos it was never possible to separate Teller's science from policy and controversy ...

  18. Mercury Sample Return using Solar Sails

    NASA Astrophysics Data System (ADS)

    Young, Roy; Montgomery, E.; Adams, C.

    2006-12-01

    Over the previous three years NASA’s In-Space Propulsion Technology (ISPT) Program has matured solar sail technology from laboratory components to full systems, demonstrated in as relevant a space environment as could be simulated on the ground. Solar sail propulsion uses sunlight to propel vehicles through space by reflecting solar photons from a large sails made of a lightweight, reflective material. With photonic pressure providing continuous thrust, sailcraft can conduct missions not available with conventional propulsion: • high-inclination plane changes • flyby or rendezvous missions to outer solar system objects • non-Keplarian orbits (e.g. above the pole of a planet) • hovering indefinitely near a Lagrange point in space To illustrate the capabilities of solar sails, the results of an European Space Agency Mercury Sample Return study using solar sails is described and compared with a mission using conventional propulsion. A conventional Mercury sample return mission requires significant launch mass due to the large Δv required for the outbound and return trips, and the large mass of a planetary lander and ascent vehicle. Solar sailing can reduce mass by delivering the lander to a low, orbit close to the terminator and providing the Δv for the return flight. The mission concept calls for a 275 m sail to deliver a lander, cruise stage and science payload to a Sun-synchronous orbit at Mercury in 2.85 years. The lander acquires samples, and conducts limited surface exploration. An ascent vehicle delivers a small vehicle containing the samples for transfer to the solar sail. The solar sail then spirals back to Earth in 1 year. Solar sailing reduces launch mass by 60% and trip time by 40%, relative to conventional mission concepts. Results of technology development activities sponsored by the ISPT Program will be provided to demonstrate the level of technology readiness for such missions.

  19. Management of the Returning Traveler with Diarrhea

    PubMed Central

    2009-01-01

    Abstract: Traveler's diarrhea (TD) strikes 20—60% of travelers visiting developing countries. It occurs shortly after the return and can be distinguished into two categories: acute and persistent TD. Acute TD, mostly caused by bacterial and viral pathogens, is usually mild and self-limited, and deserves empirical symptomatic and/or antibiotic therapy in selected cases. Fluoroquinolones are progressively superseded in this indication by azithromycin, a well tolerated macrolide active against most bacteria responsible for TD, including the quinolone-resistant species of Campylobacter jejuni that are now pervasive, especially in Southeast Asia and India. Persistent TD in the returning traveler is much rarer than its acute counterpart and may be associated with three types of causes. Persistent infections, among which Giardia and possibly Entamoeba predominate, account for a significant proportion of cases. Postinfectious processes represent a second cause and comprise temporary lactose malabsorption and postinfectious irritable bowel syndrome, now considered a major cause of persistent TD. Finally, apparently unrelated chronic diseases causing diarrhea are occasionally unmasked by TD and represent a third type of persistent TD, among which the well established case of incident inflammatory bowel disease poses intriguing pathogenesis questions. This review discusses recent advances in the field and provides practical recommendations for the management of TD in adult, immunocompetent returning travelers. PMID:21180583

  20. Cloud Thickness from Offbeam Returns - Thor Lidar

    NASA Technical Reports Server (NTRS)

    Cahalan, R.; Kolasinski, J.; McGill, M.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Physical thickness of a cloud layer, and sometimes multiple cloud layers, can be estimated from the time delay of off-beam returns from a pulsed laser source illuminating one side of the cloud layer. In particular, the time delay of light returning from the outer diffuse halo of light surrounding the beam entry point, relative to the time delay at beam center, determines the cloud physical thickness. The delay combined with the pulse stretch gives the optical thickness. The halo method works best for thick cloud layers, typically optical thickness exceeding 2, and thus compliments conventional lidar which cannot penetrate thick clouds. Cloud layer top and base have been measured independently over the ARM/SGP site using conventional laser ranging (lidar) and the top minus base thickness are compared with a cloud top halo estimate obtained from the NASA/Goddard THOR System (THOR = THickness from Offbeam Returns). THOR flies on the NASA P3, and measures the halo timings from several km above cloud top, at the same time providing conventional lidar cloud top height. The ARM/SGP micropulse lidar provides cloud base height for validation.

  1. Malaria in a returning traveler from Jamaica.

    PubMed

    Kavanaugh, Michael; Bavaro, Mary

    2014-06-01

    Malaria in Jamaica is a real, but uncommon entity and poses a health risk to our Department of Defense personnel, which should not be overlooked in returning travelers. Malaria in Jamaica was actually considered eradicated in the 1960s, but there has been a reemergence attributed to the combination of Haitian nationals as well as endemic Anopheles mosquitoes in the Kingston area. Our facility recently admitted a 33-year-old Marine who had two Emergency Department visits before being evaluated for malaria. He had returned from Kingston 14 days before presentation, which included fever, night sweats, and headache followed by a period of malaise prior to the next paroxysm. He was found to have a 1.5% parasitemia with Malaria falciparum that borders on severe malaria. Fortunately, he was treated effectively with atovaquone/proguanil and had a favorable outcome. The Center for Disease Control acknowledges that malaria is present in Jamaica, but only recommends mosquito avoidance without prophylaxis. This case emphasizes the need to consider malaria in differential diagnosis in Jamaica as well as in any returning travelers with fever because of broad global travel.

  2. Earnings Quality Measures and Excess Returns.

    PubMed

    Perotti, Pietro; Wagenhofer, Alfred

    2014-06-01

    This paper examines how commonly used earnings quality measures fulfill a key objective of financial reporting, i.e., improving decision usefulness for investors. We propose a stock-price-based measure for assessing the quality of earnings quality measures. We predict that firms with higher earnings quality will be less mispriced than other firms. Mispricing is measured by the difference of the mean absolute excess returns of portfolios formed on high and low values of a measure. We examine persistence, predictability, two measures of smoothness, abnormal accruals, accruals quality, earnings response coefficient and value relevance. For a large sample of US non-financial firms over the period 1988-2007, we show that all measures except for smoothness are negatively associated with absolute excess returns, suggesting that smoothness is generally a favorable attribute of earnings. Accruals measures generate the largest spread in absolute excess returns, followed by smoothness and market-based measures. These results lend support to the widespread use of accruals measures as overall measures of earnings quality in the literature.

  3. Earnings Quality Measures and Excess Returns

    PubMed Central

    Perotti, Pietro; Wagenhofer, Alfred

    2014-01-01

    This paper examines how commonly used earnings quality measures fulfill a key objective of financial reporting, i.e., improving decision usefulness for investors. We propose a stock-price-based measure for assessing the quality of earnings quality measures. We predict that firms with higher earnings quality will be less mispriced than other firms. Mispricing is measured by the difference of the mean absolute excess returns of portfolios formed on high and low values of a measure. We examine persistence, predictability, two measures of smoothness, abnormal accruals, accruals quality, earnings response coefficient and value relevance. For a large sample of US non-financial firms over the period 1988–2007, we show that all measures except for smoothness are negatively associated with absolute excess returns, suggesting that smoothness is generally a favorable attribute of earnings. Accruals measures generate the largest spread in absolute excess returns, followed by smoothness and market-based measures. These results lend support to the widespread use of accruals measures as overall measures of earnings quality in the literature. PMID:26300582

  4. 21 CFR 111.520 - When may a returned dietary supplement be salvaged?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false When may a returned dietary supplement be salvaged? 111.520 Section 111.520 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CURRENT GOOD MANUFACTURING PRACTICE IN...

  5. 21 CFR 111.510 - What requirements apply when a returned dietary supplement is received?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false What requirements apply when a returned dietary supplement is received? 111.510 Section 111.510 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CURRENT GOOD MANUFACTURING PRACTICE...

  6. Cluster of zoonotic cutaneous leishmaniasis (Leishmania major) in European travelers returning from Turkmenistan.

    PubMed

    Larréché, Sébastien; Launay, Grégoire; Weibel Galluzzo, Christelle; Bousquet, Aurore; Eperon, Gilles; Pilo, Jean-Etienne; Ravel, Christophe; Chappuis, François; Dupin, Michel; Mérens, Audrey

    2013-01-01

    We report a cluster of cutaneous leishmaniasis due to Leishmania major in four immunocompetent travelers returning from Western Turkmenistan and having atypical and/or multiple lesions. Treatments with pentamidine or fluconazole were effective. Physicians should be aware that some virulent strains of L major currently circulate in Central Asia.

  7. Brain Gain or Brain Circulation? U.S. Doctoral Recipients Returning to South Korea

    ERIC Educational Resources Information Center

    Lee, Jenny J.; Kim, Dongbin

    2010-01-01

    This study explored the reasons for current reverse mobility patterns in South Korea and how the country benefits from returning U.S. doctoral recipients in the forms of brain gain and brain circulation. Based on interviews of Korean faculty who studied in the U.S., this study found that while the political economy might help to explain why Korean…

  8. School Leadership Preparation and Development in Kenya: Evaluating Performance Impact and Return on Leadership Development Investment

    ERIC Educational Resources Information Center

    Asuga, Gladys; Eacott, Scott; Scevak, Jill

    2015-01-01

    Purpose: The purpose of this paper is to evaluate the quality of the current provision for school leadership in Kenya, the extent to which they have an impact on student outcomes and the return on school leadership preparation and development investment. Design/Methodology/Approach: The paper draws from educational leadership, management and…

  9. Is It Ever Too Late to Study? The Economic Returns on Late Tertiary Degrees in Sweden

    ERIC Educational Resources Information Center

    Hallsten, Martin

    2012-01-01

    This paper addresses the economic returns on tertiary degrees obtained in ages above 30 for individuals with upper-secondary schooling in light of current ideas on lifelong learning. Sweden is a case in point: Swedish tertiary education is open to older students, and labor market legislation supports employees who take a leave to study. The…

  10. Severe malaria not responsive to artemisinin derivatives in man returning from Angola to Vietnam.

    PubMed

    Van Hong, Nguyen; Amambua-Ngwa, Alfred; Tuan, Nguyen Quang; Cuong, Do Duy; Giang, Nguyen Thi Huong; Van Dung, Nguyen; Tinh, Ta Thi; Van Tien, Nguyen; Phuc, Bui Quang; Duong, Tran Thanh; Rosanas-Urgell, Anna; D'Alessandro, Umberto; Van Geertruyden, Jean-Pierre; Erhart, Annette

    2014-07-01

    Resistance to artemisinin derivatives, the most potent antimalarial drugs currently used, has emerged in Southeast Asia and threatens to spread to Africa. We report a case of malaria in a man who returned to Vietnam after 3 years in Angola that did not respond to intravenous artesunate and clindamycin or an oral artemisinin-based combination.

  11. Women's Job-Related Training in Canada: Returns to Human Capital Investments

    ERIC Educational Resources Information Center

    Quinlan, Elizabeth

    2008-01-01

    The prevailing discourse informing most Canadian training and labor market policy assumes a positive link between individuals' training and their labor market returns in the new knowledge economy. The primary objective of the study is to test the current rhetoric by developing a statistical model of women's job-related training. Training…

  12. 21 CFR 111.130 - What quality control operations are required for returned dietary supplements?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false What quality control operations are required for returned dietary supplements? 111.130 Section 111.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CURRENT GOOD...

  13. 77 FR 47426 - Agency Information Collection Activities: Request for the Return of Original Documents, Form...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-08

    ... the Return of Original Documents, Form Number G-884; Extension, Without Change, of a Currently... this 60-day period, USCIS will be evaluating whether to revise the Form G-884. Should USCIS decide to revise Form G-884, we will advise the public when we publish the 30-day notice in the Federal Register...

  14. 21 CFR 111.520 - When may a returned dietary supplement be salvaged?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false When may a returned dietary supplement be salvaged? 111.520 Section 111.520 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CURRENT GOOD MANUFACTURING PRACTICE IN...

  15. 21 CFR 111.510 - What requirements apply when a returned dietary supplement is received?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false What requirements apply when a returned dietary supplement is received? 111.510 Section 111.510 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CURRENT GOOD MANUFACTURING PRACTICE...

  16. 2016 Consensus statement on return to sport from the First World Congress in Sports Physical Therapy, Bern.

    PubMed

    Ardern, Clare L; Glasgow, Philip; Schneiders, Anthony; Witvrouw, Erik; Clarsen, Benjamin; Cools, Ann; Gojanovic, Boris; Griffin, Steffan; Khan, Karim M; Moksnes, Håvard; Mutch, Stephen A; Phillips, Nicola; Reurink, Gustaaf; Sadler, Robin; Silbernagel, Karin Grävare; Thorborg, Kristian; Wangensteen, Arnlaug; Wilk, Kevin E; Bizzini, Mario

    2016-07-01

    Deciding when to return to sport after injury is complex and multifactorial-an exercise in risk management. Return to sport decisions are made every day by clinicians, athletes and coaches, ideally in a collaborative way. The purpose of this consensus statement was to present and synthesise current evidence to make recommendations for return to sport decision-making, clinical practice and future research directions related to returning athletes to sport. A half day meeting was held in Bern, Switzerland, after the First World Congress in Sports Physical Therapy. 17 expert clinicians participated. 4 main sections were initially agreed upon, then participants elected to join 1 of the 4 groups-each group focused on 1 section of the consensus statement. Participants in each group discussed and summarised the key issues for their section before the 17-member group met again for discussion to reach consensus on the content of the 4 sections. Return to sport is not a decision taken in isolation at the end of the recovery and rehabilitation process. Instead, return to sport should be viewed as a continuum, paralleled with recovery and rehabilitation. Biopsychosocial models may help the clinician make sense of individual factors that may influence the athlete's return to sport, and the Strategic Assessment of Risk and Risk Tolerance framework may help decision-makers synthesise information to make an optimal return to sport decision. Research evidence to support return to sport decisions in clinical practice is scarce. Future research should focus on a standardised approach to defining, measuring and reporting return to sport outcomes, and identifying valuable prognostic factors for returning to sport.

  17. Scientific Collaborations: How Do We Measure the Return on Relationships?

    PubMed Central

    Fair, Jeanne M.; Stokes, Martha Mangum; Pennington, Deana; Mendenhall, Ian H.

    2016-01-01

    Emerging infectious diseases (EIDs), the majority of which are zoonotic, represent a tremendous challenge for public health and biosurveillance infrastructure across the globe. Due to the complexity of zoonotic pathogens, it is essential that research and response to EIDs be a transdisciplinary effort. And while crisis and circumstance may be the initial catalyst for responding to an outbreak, we provide examples of how transdisciplinary scientific collectives, which are organized and solidified in advance of crises, can transform the way the world responds to outbreaks and in some cases could even prevent one from occurring (1). Current methods for assessing whether a cooperative engagement between countries is producing measurable and sustainable value is based on the ideas of return on investment and do not consider the inherent importance of relationships. In this article, we apply the idea of return on relationships (ROR) and propose a method for measuring ROR, using a system dynamics modeling framework commonly used in epidemiology. Tracking the numerous and diverse scientific collaborations that emerged from a training workshop for biosurveillance of bats held in Singapore in 2014, we apply a methodology for visualizing and measuring the relationship networks and outcomes that result. Additionally, the collaborative, multidisciplinary network that coalesced in response to the Hantavirus outbreak in New Mexico is 1993 is discussed as an example of the long-term benefits of ROR. PMID:26913278

  18. Venus Surface Sample Return: A Weighty High-Pressure Challenge

    NASA Technical Reports Server (NTRS)

    Sweetser, Ted; Cameron, Jonathon; Chen, Gun-Shing; Cutts, Jim; Gershman, Bob; Gilmore, Martha S.; Hall, Jeffrey L.; Kerzhanovich, Viktor; McRonald, Angus; Nilsen, Erik

    1999-01-01

    A mission to return a sample to Earth from the surface of Venus faces a multitude of multidisciplinary challenges. In addition to the complications inherent in any sample return mission, Venus presents the additional difficulties of a deep gravity well essentially equivalent to Earth's and a hot-house atmosphere which generates extremes of high temperature, density, and pressure unmatched at any other known surface in the solar system. The Jet Propulsion Laboratory of the California Institute of Technology recently conducted a study to develop an architecture for such a mission; a major goal of this study was to identify technology developments which would need to be pursued in order to make such a mission feasible at a cost much less than estimated in previous. The final design of this mission is years away but the study results presented here show our current mission architecture as it applies to a particular mission opportunity, give a summary of the engineering and science trades which were made in the process of developing it, and identify the main technology development efforts needed.

  19. Zika without symptoms in returning travellers: What are the implications?

    PubMed

    Ginier, Mylène; Neumayr, Andreas; Günther, Stephan; Schmidt-Chanasit, Jonas; Blum, Johannes

    2016-01-01

    Against the background of the emergence and rapid spread of Zika virus (ZIKV) in the Americas, we report the case of an afebrile ZIKV infection in a traveller returning from Central America to highlight relevant clinical and diagnostic aspects. ZIKV should be considered in the differential diagnosis of patients with clinical symptoms suggestive of dengue or chikungunya fever. Given the frequent subfebril and afebrile manifestations of ZIKV infections, we propose abstaining from the term "Zika fever (ZF)" in favour of "Zika virus disease (ZVD)". Owing to its unspecific clinical presentation and cross-reactivity in serological assays, ZVD may easily be missed or misdiagnosed as dengue fever. Until conclusive data on the currently suspected link between ZIKV infection in pregnancy and foetal microcephaly become available, pregnant women and women who are trying to become pregnant should be advised against travelling to regions with ongoing ZIKV transmission. In addition, male travellers returning from regions with ongoing transmission should be informed of the potential risk of sexual transmission until conclusive data on the significance of this mode of transmission become available. Although probably low and seasonally restricted, there is a risk of ZIKV importation to Aedes mosquito-infested regions in temperate climates (including regions of North America and Europe) with consecutive autochthonous transmission.

  20. Scientific Collaborations: How Do We Measure the Return on Relationships?

    PubMed

    Fair, Jeanne M; Stokes, Martha Mangum; Pennington, Deana; Mendenhall, Ian H

    2016-01-01

    Emerging infectious diseases (EIDs), the majority of which are zoonotic, represent a tremendous challenge for public health and biosurveillance infrastructure across the globe. Due to the complexity of zoonotic pathogens, it is essential that research and response to EIDs be a transdisciplinary effort. And while crisis and circumstance may be the initial catalyst for responding to an outbreak, we provide examples of how transdisciplinary scientific collectives, which are organized and solidified in advance of crises, can transform the way the world responds to outbreaks and in some cases could even prevent one from occurring (1). Current methods for assessing whether a cooperative engagement between countries is producing measurable and sustainable value is based on the ideas of return on investment and do not consider the inherent importance of relationships. In this article, we apply the idea of return on relationships (ROR) and propose a method for measuring ROR, using a system dynamics modeling framework commonly used in epidemiology. Tracking the numerous and diverse scientific collaborations that emerged from a training workshop for biosurveillance of bats held in Singapore in 2014, we apply a methodology for visualizing and measuring the relationship networks and outcomes that result. Additionally, the collaborative, multidisciplinary network that coalesced in response to the Hantavirus outbreak in New Mexico is 1993 is discussed as an example of the long-term benefits of ROR.

  1. Energy Return On Investment of Engineered Geothermal Systems Data

    DOE Data Explorer

    Mansure, Chip

    2012-01-01

    The project provides an updated Energy Return on Investment (EROI) for Enhanced Geothermal Systems (EGS). Results incorporate Argonne National Laboratory's Life Cycle Assessment and base case assumptions consistent with other projects in the Analysis subprogram. EROI is a ratio of the energy delivered to the consumer to the energy consumed to build, operate, and decommission the facility. EROI is important in assessing the viability of energy alternatives. Currently EROI analyses of geothermal energy are either out-of-date, of uncertain methodology, or presented online with little supporting documentation. This data set is a collection of files documenting data used to calculate the Energy Return On Investment (EROI) of Engineered Geothermal Systems (EGS) and erratum to publications prior to the final report. Final report is available from the OSTI web site (http://www.osti.gov/geothermal/). Data in this collections includes the well designs used, input parameters for GETEM, a discussion of the energy needed to haul materials to the drill site, the baseline mud program, and a summary of the energy needed to drill each of the well designs. EROI is the ratio of the energy delivered to the customer to the energy consumed to construct, operate, and decommission the facility. Whereas efficiency is the ratio of the energy delivered to the customer to the energy extracted from the reservoir.

  2. Earth Return Aerocapture for the TransHab/Ellipsled Vehicle

    NASA Technical Reports Server (NTRS)

    Muth, W. D.; Hoffmann, C.; Lyne, J. E.

    2000-01-01

    The current architecture being considered by NASA for a human Mars mission involves the use of an aerocapture procedure at Mars arrival and possibly upon Earth return. This technique would be used to decelerate the vehicles and insert them into their desired target orbits, thereby eliminating the need for propulsive orbital insertions. The crew may make the interplanetary journey in a large, inflatable habitat known as the TransHab. It has been proposed that upon Earth return, this habitat be captured into orbit for use on subsequent missions. In this case, the TransHab would be complimented with an aeroshell, which would protect it from heating during the atmospheric entry and provide the vehicle with aerodynamic lift. The aeroshell has been dubbed the "Ellipsled" because of its characteristic shape. This paper reports the results of a preliminary study of the aerocapture of the TransHab/Ellipsled vehicle upon Earth return. Undershoot and overshoot boundaries have been determined for a range of entry velocities, and the effects of variations in the atmospheric density profile, the vehicle deceleration limit, the maximum vehicle roll rate, the target orbit, and the vehicle ballistic coefficient have been examined. A simple, 180 degree roll maneuver was implemented in the undershoot trajectories to target the desired 407 km circular Earth orbit. A three-roll sequence was developed to target not only a specific orbital energy, but also a particular inclination, thereby decreasing propulsive inclination changes and post-aerocapture delta-V requirements. Results show that the TransHab/Ellipsled vehicle has a nominal corridor width of at least 0.7 degrees for entry speeds up to 14.0 km/s. Most trajectories were simulated using continuum flow aerodynamics, but the impact of high-altitude viscous effects was evaluated and found to be minimal. In addition, entry corridor comparisons have been made between the TransHab/Ellipsled and a modified Apollo capsule which is also

  3. 78 FR 49296 - Centennial Challenges 2014 Sample Return Robot Challenge

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-13

    ... SPACE ADMINISTRATION Centennial Challenges 2014 Sample Return Robot Challenge AGENCY: National Aeronautics and Space Administration (NASA). ACTION: Notice of Centennial Challenges 2014 Sample Return Robot... Robot Challenge is scheduled and teams that wish to compete may register. Centennial Challenges is...

  4. 49 CFR 236.720 - Circuit, common return.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.720 Circuit, common return. A term applied where one wire is used for the return of more than one...

  5. NASA's Planned Return to the Moon: Global Access and Anytime Return Requirement Implications on the Lunar Orbit Insertion Burns

    NASA Technical Reports Server (NTRS)

    Garn, Michelle; Qu, Min; Chrone, Jonathan; Su, Philip; Karlgaard, Chris

    2008-01-01

    Lunar orbit insertion LOI is a critical maneuver for any mission going to the Moon. Optimizing the geometry of this maneuver is crucial to the success of the architecture designed to return humans to the Moon. LOI burns necessary to meet current NASA Exploration Constellation architecture requirements for the lunar sortie missions are driven mainly by the requirement for global access and "anytime" return from the lunar surface. This paper begins by describing the Earth-Moon geometry which creates the worst case (delta)V for both the LOI and the translunar injection (TLI) maneuvers over the full metonic cycle. The trajectory which optimizes the overall (delta)V performance of the mission is identified, trade studies results covering the entire lunar globe are mapped onto the contour plots, and the effects of loitering in low lunar orbit as a means of reducing the insertion (delta)V are described. Finally, the lighting conditions on the lunar surface are combined with the LOI and TLI analyses to identify geometries with ideal lighting conditions at sites of interest which minimize the mission (delta)V.

  6. Calculations of lightning return stroke electric and magnetic fields above ground

    NASA Technical Reports Server (NTRS)

    Master, M. J.; Uman, M. A.; Ling, Y. T.; Standler, R. B.

    1981-01-01

    Lin et al., (1980) presented a lightning return stroke model with which return stroke electric and magnetic fields measured at ground level could be reproduced. This model and a modified version of it, in which the initial current peak decays with height above ground, are used to compute waveforms for altitudes from 0-10 km and at ranges of 20 m to 10 km. Both the original and modified models gave accurate predictions of measured ground-based fields. The use of the calculated fields in calibrating airborne field measurements from simultaneous ground and airborne data is discussed.

  7. The changes on physical characteristics of lightning discharge plasma during individual return stroke process

    SciTech Connect

    Xu, He; Yuan, Ping; Cen, Jian-Yong; Zhang, Guang-Shu

    2014-03-15

    A cloud-to-ground lightning with six return strokes has been recorded with a slit-less spectrograph in Qinghai province. According to the spectra of return strokes without continuous current, the electron density, the channel temperature, and the gas pressure have been calculated. Then, the correlativity of these parameters has been analyzed. The results indicate that the total intensity of spectra is positive correlated to the intensity of spectral line, they both decrease with time rapidly; furthermore, the channel temperature and the gas pressure decrease with time slowly in the similar trends.

  8. Trajectory design for a Mars Rover/Sample Return mission

    NASA Astrophysics Data System (ADS)

    Sweetser, Theodore H.

    This paper discusses two of the orbit design problems faced in the design of a Mars Rover/Sample Return mission, which is currently being studied at the Jet Propulsion Laboratory. The first is the problem of interplanetary transfer - what is the best trajectory for getting equipment to Mars and a sample back. Several kinds of trajectories are examined before the conclusion is made that straightforward direct transfers are best. The second orbit design problem is what kind of orbit around Mars is best for making high-resolution maps of sites where the rover could land and gather samples, and how can the same orbiter be used as a relay between a rover on Mars and ground stations on Earth. This question is examined in the context of alternate mission options being considered, and the answer depends on the requirements of the particular mission option.

  9. Academic Specialisation and Returns to Education: Evidence from India

    ERIC Educational Resources Information Center

    Saha, Bibhas; Sensarma, Rudra

    2011-01-01

    We study returns to academic specialisation for Indian corporate sector workers by analysing cross-sectional data on male employees randomly selected from six large firms. Our analysis shows that going to college pays off, as it brings significant incremental returns over and above school education. However, the increase in returns is more…

  10. 76 FR 56819 - Centennial Challenges 2012 Sample Return Robot Challenge

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... SPACE ADMINISTRATION Centennial Challenges 2012 Sample Return Robot Challenge AGENCY: National... 42 U.S.C. 2451(314)(d). The 2012 Sample Return Robot Challenge is scheduled and teams that wish to... technologies of interest and value to NASA and the nation. The 2012 Sample Return Robot Challenge is a...

  11. 29 CFR 825.311 - Intent to return to work.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Intent to return to work. 825.311 Section 825.311 Labor... Intent to return to work. (a) An employer may require an employee on FMLA leave to report periodically on the employee's status and intent to return to work. The employer's policy regarding such reports...

  12. 47 CFR 65.600 - Rate of return reports.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Rate of return reports. 65.600 Section 65.600 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERSTATE RATE OF RETURN PRESCRIPTION PROCEDURES AND METHODOLOGIES Rate of Return Reports § 65.600 Rate of...

  13. Supporting Women Returning to Work: A European Perspective.

    ERIC Educational Resources Information Center

    Shepherd, Jan; Saxby-Smith, Sue

    A 2-year project examined the effectiveness of courses for returning workers in enabling women to make a sustained return to paid employment in the following countries: France; Spain; Ireland; and the United Kingdom. In each country, a short foundation-level program and a longer accredited return-to-work program were selected for evaluation.…

  14. 26 CFR 53.7701-1 - Tax return preparer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Tax return preparer. 53.7701-1 Section 53.7701... EXCISE TAXES (CONTINUED) FOUNDATION AND SIMILAR EXCISE TAXES Procedure and Administration § 53.7701-1 Tax return preparer. (a) In general. For the definition of a tax return preparer, see § 301.7701-15 of...

  15. 26 CFR 156.7701-1 - Tax return preparer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Tax return preparer. 156.7701-1 Section 156... EXCISE TAXES (CONTINUED) EXCISE TAX ON GREENMAIL Procedure and Administration § 156.7701-1 Tax return preparer. (a) In general. For the definition of a tax return preparer, see § 301.7701-15 of this...

  16. 26 CFR 56.7701-1 - Tax return preparer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Tax return preparer. 56.7701-1 Section 56.7701... EXCISE TAXES (CONTINUED) PUBLIC CHARITY EXCISE TAXES § 56.7701-1 Tax return preparer. (a) In general. For the definition of a tax return preparer, see § 301.7701-15 of this chapter. (b)...

  17. 26 CFR 54.7701-1 - Tax return preparer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Tax return preparer. 54.7701-1 Section 54.7701... EXCISE TAXES (CONTINUED) PENSION EXCISE TAXES § 54.7701-1 Tax return preparer. (a) In general. For the definition of a tax return preparer, see § 301.7701-15 of this chapter. (b) Effective/applicability...

  18. 26 CFR 40.7701-1 - Tax return preparer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 16 2011-04-01 2011-04-01 false Tax return preparer. 40.7701-1 Section 40.7701... EXCISE TAXES EXCISE TAX PROCEDURAL REGULATIONS § 40.7701-1 Tax return preparer. (a) In general. For the definition of a tax return preparer, see § 301.7701-15 of this chapter. (b) Effective/applicability...

  19. 26 CFR 40.7701-1 - Tax return preparer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 16 2013-04-01 2013-04-01 false Tax return preparer. 40.7701-1 Section 40.7701... EXCISE TAXES EXCISE TAX PROCEDURAL REGULATIONS § 40.7701-1 Tax return preparer. (a) In general. For the definition of a tax return preparer, see § 301.7701-15 of this chapter. (b) Effective/applicability...

  20. 27 CFR 25.211 - Beer returned to brewery.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Beer returned to brewery..., DEPARTMENT OF THE TREASURY ALCOHOL BEER Beer Returned to Brewery § 25.211 Beer returned to brewery. (a) General. Beer, produced in the United States, on which the brewer has paid or determined the tax may...

  1. 27 CFR 25.211 - Beer returned to brewery.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Beer returned to brewery..., DEPARTMENT OF THE TREASURY LIQUORS BEER Beer Returned to Brewery § 25.211 Beer returned to brewery. (a) General. Beer, produced in the United States, on which the brewer has paid or determined the tax may...

  2. 27 CFR 25.211 - Beer returned to brewery.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Beer returned to brewery..., DEPARTMENT OF THE TREASURY ALCOHOL BEER Beer Returned to Brewery § 25.211 Beer returned to brewery. (a) General. Beer, produced in the United States, on which the brewer has paid or determined the tax may...

  3. 27 CFR 25.211 - Beer returned to brewery.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Beer returned to brewery..., DEPARTMENT OF THE TREASURY LIQUORS BEER Beer Returned to Brewery § 25.211 Beer returned to brewery. (a) General. Beer, produced in the United States, on which the brewer has paid or determined the tax may...

  4. 26 CFR 301.6063-1 - Signing of partnership returns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Signing of partnership returns. 301.6063-1 Section 301.6063-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED....6063-1 Signing of partnership returns. For provisions relating to the signing of returns of...

  5. 26 CFR 301.6063-1 - Signing of partnership returns.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 18 2011-04-01 2011-04-01 false Signing of partnership returns. 301.6063-1 Section 301.6063-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED....6063-1 Signing of partnership returns. For provisions relating to the signing of returns of...

  6. 26 CFR 301.6063-1 - Signing of partnership returns.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 18 2012-04-01 2012-04-01 false Signing of partnership returns. 301.6063-1 Section 301.6063-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED....6063-1 Signing of partnership returns. For provisions relating to the signing of returns of...

  7. 26 CFR 301.6063-1 - Signing of partnership returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 18 2013-04-01 2013-04-01 false Signing of partnership returns. 301.6063-1 Section 301.6063-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED....6063-1 Signing of partnership returns. For provisions relating to the signing of returns of...

  8. 26 CFR 301.6063-1 - Signing of partnership returns.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 18 2014-04-01 2014-04-01 false Signing of partnership returns. 301.6063-1 Section 301.6063-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED....6063-1 Signing of partnership returns. For provisions relating to the signing of returns of...

  9. 19 CFR 145.35 - United States products returned.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false United States products returned. 145.35 Section... OF THE TREASURY (CONTINUED) MAIL IMPORTATIONS Special Classes of Merchandise § 145.35 United States products returned. Products of the United States returned after having been exported, which have not...

  10. 19 CFR 145.35 - United States products returned.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 2 2014-04-01 2014-04-01 false United States products returned. 145.35 Section... OF THE TREASURY (CONTINUED) MAIL IMPORTATIONS Special Classes of Merchandise § 145.35 United States products returned. Products of the United States returned after having been exported, which have not...

  11. 19 CFR 145.35 - United States products returned.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 2 2011-04-01 2011-04-01 false United States products returned. 145.35 Section... OF THE TREASURY (CONTINUED) MAIL IMPORTATIONS Special Classes of Merchandise § 145.35 United States products returned. Products of the United States returned after having been exported, which have not...

  12. 19 CFR 145.35 - United States products returned.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 2 2013-04-01 2013-04-01 false United States products returned. 145.35 Section... OF THE TREASURY (CONTINUED) MAIL IMPORTATIONS Special Classes of Merchandise § 145.35 United States products returned. Products of the United States returned after having been exported, which have not...

  13. 19 CFR 145.35 - United States products returned.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 2 2012-04-01 2012-04-01 false United States products returned. 145.35 Section... OF THE TREASURY (CONTINUED) MAIL IMPORTATIONS Special Classes of Merchandise § 145.35 United States products returned. Products of the United States returned after having been exported, which have not...

  14. 78 FR 13899 - Revision of Annual Information Return/Reports

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-01

    ... Benefits Security Administration RIN 1210-AB51 Revision of Annual Information Return/Reports AGENCY... Annual Return/Report is the principal source of information and data concerning the operations, funding... would have on the information collection request titled ``Form 5500, Annual Return/Report of...

  15. 22 CFR 42.22 - Returning resident aliens.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Returning resident aliens. 42.22 Section 42.22... Returning resident aliens. (a) Requirements for returning resident status. An alien shall be classifiable as... presented that: (1) The alien had the status of an alien lawfully admitted for permanent residence at...

  16. 22 CFR 42.22 - Returning resident aliens.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Returning resident aliens. 42.22 Section 42.22... Returning resident aliens. (a) Requirements for returning resident status. An alien shall be classifiable as... presented that: (1) The alien had the status of an alien lawfully admitted for permanent residence at...

  17. 22 CFR 42.22 - Returning resident aliens.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Returning resident aliens. 42.22 Section 42.22... Returning resident aliens. (a) Requirements for returning resident status. An alien shall be classifiable as... presented that: (1) The alien had the status of an alien lawfully admitted for permanent residence at...

  18. 22 CFR 42.22 - Returning resident aliens.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Returning resident aliens. 42.22 Section 42.22... Returning resident aliens. (a) Requirements for returning resident status. An alien shall be classifiable as... presented that: (1) The alien had the status of an alien lawfully admitted for permanent residence at...

  19. 22 CFR 42.22 - Returning resident aliens.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Returning resident aliens. 42.22 Section 42.22... Returning resident aliens. (a) Requirements for returning resident status. An alien shall be classifiable as... presented that: (1) The alien had the status of an alien lawfully admitted for permanent residence at...

  20. 27 CFR 25.211 - Beer returned to brewery.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Beer returned to brewery..., DEPARTMENT OF THE TREASURY LIQUORS BEER Beer Returned to Brewery § 25.211 Beer returned to brewery. (a) General. Beer, produced in the United States, on which the brewer has paid or determined the tax may...

  1. 27 CFR 53.185 - Credit on returns.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2012-04-01 2011-04-01 true Credit on returns. 53.185... Other Administrative Provisions of Special Application to Manufacturers Taxes § 53.185 Credit on returns..., in lieu of claiming refund of the overpayment, claim credit for the overpayment on any return of...

  2. 26 CFR 48.6416(f)-1 - Credit on returns.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 16 2012-04-01 2012-04-01 false Credit on returns. 48.6416(f)-1 Section 48.6416... Special Application to Retailers and Manufacturers Taxes § 48.6416(f)-1 Credit on returns. Any person..., in lieu of claiming refund of the overpayment, claim credit for the overpayment on any return of...

  3. 26 CFR 48.6416(f)-1 - Credit on returns.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 16 2011-04-01 2011-04-01 false Credit on returns. 48.6416(f)-1 Section 48.6416... Special Application to Retailers and Manufacturers Taxes § 48.6416(f)-1 Credit on returns. Any person..., in lieu of claiming refund of the overpayment, claim credit for the overpayment on any return of...

  4. 26 CFR 48.6416(f)-1 - Credit on returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 16 2013-04-01 2013-04-01 false Credit on returns. 48.6416(f)-1 Section 48.6416... Special Application to Retailers and Manufacturers Taxes § 48.6416(f)-1 Credit on returns. Any person..., in lieu of claiming refund of the overpayment, claim credit for the overpayment on any return of...

  5. 27 CFR 53.185 - Credit on returns.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2013-04-01 2013-04-01 false Credit on returns. 53.185... Other Administrative Provisions of Special Application to Manufacturers Taxes § 53.185 Credit on returns..., in lieu of claiming refund of the overpayment, claim credit for the overpayment on any return of...

  6. 26 CFR 48.6416(f)-1 - Credit on returns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Credit on returns. 48.6416(f)-1 Section 48.6416... Special Application to Retailers and Manufacturers Taxes § 48.6416(f)-1 Credit on returns. Any person..., in lieu of claiming refund of the overpayment, claim credit for the overpayment on any return of...

  7. Parametrization of Fresnel returns in middle-atmosphere radar experiments

    NASA Technical Reports Server (NTRS)

    Rastogi, P. K.

    1983-01-01

    Weak reflections from sharp discontinuities in radio refractivity are usually invoked to explain the results of radio propagation experiments. The characteristics of refractivity structures required to produce Fresnel returns are examined and experimental evidence for Fresnel returns in middle-atmosphere radar experiments is reviewed. The consequences of these returns on estimating the turbulence and wind parameters are outlined.

  8. Welfare Returns and Temporary Time Limits: A Proportional Hazard Model

    ERIC Educational Resources Information Center

    Albert, Vicky N.; King, William C.; Iaci, Ross

    2007-01-01

    This study analyzes welfare returns for families who leave welfare for a "sit-out" period of 12 months in response to a temporary time limit requirement in Nevada. Findings reveal that relatively few families return for cash assistance after sitting out and that the majority who do return soon after their sit-out period is complete.…

  9. 10 CFR 436.22 - Adjusted internal rate of return.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Methodology and Procedures for Life Cycle Cost Analyses § 436.22 Adjusted internal rate of return. The adjusted internal rate of return is the overall rate of return on an energy or water conservation measure... yearly net savings in energy or water and non-fuel or non-water operation and maintenance...

  10. 10 CFR 436.22 - Adjusted internal rate of return.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Methodology and Procedures for Life Cycle Cost Analyses § 436.22 Adjusted internal rate of return. The adjusted internal rate of return is the overall rate of return on an energy or water conservation measure... yearly net savings in energy or water and non-fuel or non-water operation and maintenance...

  11. 46 CFR 113.10-5 - Common return.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Common return. 113.10-5 Section 113.10-5 Shipping COAST... SYSTEMS AND EQUIPMENT Fire and Smoke Detecting and Alarm Systems § 113.10-5 Common return. A conductor must not be used as a common return from more than one zone....

  12. Why we need asteroid sample return mission?

    NASA Astrophysics Data System (ADS)

    Barucci, Maria Antonietta

    2016-07-01

    Small bodies retain evidence of the primordial solar nebula and the earliest solar system processes that shaped their evolution. They may also contain pre-solar material as well as complex organic molecules, which could have a major role to the development of life on Earth. For these reasons, asteroids and comets have been targets of interest for missions for over three decades. However, our knowledge of these bodies is still very limited, and each asteroid or comet visited by space mission has revealed unexpected scientific results, e.g. the structure and nature of comet 67P/Churyumov-Gerasimenko (67P/C-G) visited by the Rosetta mission. Only in the laboratory can instruments with the necessary precision and sensitivity be applied to individual components of the complex mixture of materials that forms a small body regolith, to determine their precise chemical and isotopic composition. Such measurements are vital for revealing the evidence of stellar, interstellar medium, pre-solar nebula and parent body processes that are retained in primitive material, unaltered by atmospheric entry or terrestrial contamination. For those reasons, sample return missions are considered a high priority by a number of the leading space agencies. Abundant within the inner Solar System and the main impactors on terrestrial planets, small bodies may have been the principal contributors of the water and organic material essential to create life on Earth. Small bodies can therefore be considered to be equivalent to DNA for unravelling our solar system's history, offering us a unique window to investigate both the formation of planets and the origin of life. A sample return mission to a primitive Near-Earth Asteroid (NEA) has been study at ESA from 2008 in the framework of ESA's Cosmic Vision (CV) programme, with the objective to answer to the fundamental CV questions "How does the Solar System work?" and "What are the conditions for life and planetary formations?". The returned material

  13. 26 CFR 1.1502-79A - Separate return years generally applicable for consolidated return years beginning before January...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... December 31, 1967. (ii) P, S, and T join in the filing of a consolidated return for 1968, which return... Testing Dates (and Corporations Joining or Leaving Consolidated Groups) Before June 25, 1999...

  14. 26 CFR 26.6109-1 - Tax return preparers furnishing identifying numbers for returns or claims for refund.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) ESTATE AND GIFT TAXES GENERATION-SKIPPING TRANSFER TAX... for returns or claims for refund. (a) In general. Each generation-skipping transfer tax return...

  15. 26 CFR 26.6109-1 - Tax return preparers furnishing identifying numbers for returns or claims for refund.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) ESTATE AND GIFT TAXES GENERATION-SKIPPING TRANSFER TAX... for returns or claims for refund. (a) In general. Each generation-skipping transfer tax return...

  16. 26 CFR 26.6109-1 - Tax return preparers furnishing identifying numbers for returns or claims for refund.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) ESTATE AND GIFT TAXES GENERATION-SKIPPING TRANSFER TAX... for returns or claims for refund. (a) In general. Each generation-skipping transfer tax return...

  17. 26 CFR 26.6109-1 - Tax return preparers furnishing identifying numbers for returns or claims for refund.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) ESTATE AND GIFT TAXES GENERATION-SKIPPING TRANSFER TAX... for returns or claims for refund. (a) In general. Each generation-skipping transfer tax return...

  18. 26 CFR 26.6109-1 - Tax return preparers furnishing identifying numbers for returns or claims for refund.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) ESTATE AND GIFT TAXES GENERATION-SKIPPING TRANSFER TAX... for returns or claims for refund. (a) In general. Each generation-skipping transfer tax return...

  19. Recommended Maximum Temperature For Mars Returned Samples

    NASA Technical Reports Server (NTRS)

    Beaty, D. W.; McSween, H. Y.; Czaja, A. D.; Goreva, Y. S.; Hausrath, E.; Herd, C. D. K.; Humayun, M.; McCubbin, F. M.; McLennan, S. M.; Hays, L. E.

    2016-01-01

    The Returned Sample Science Board (RSSB) was established in 2015 by NASA to provide expertise from the planetary sample community to the Mars 2020 Project. The RSSB's first task was to address the effect of heating during acquisition and storage of samples on scientific investigations that could be expected to be conducted if the samples are returned to Earth. Sample heating may cause changes that could ad-versely affect scientific investigations. Previous studies of temperature requirements for returned mar-tian samples fall within a wide range (-73 to 50 degrees Centigrade) and, for mission concepts that have a life detection component, the recommended threshold was less than or equal to -20 degrees Centigrade. The RSSB was asked by the Mars 2020 project to determine whether or not a temperature requirement was needed within the range of 30 to 70 degrees Centigrade. There are eight expected temperature regimes to which the samples could be exposed, from the moment that they are drilled until they are placed into a temperature-controlled environment on Earth. Two of those - heating during sample acquisition (drilling) and heating while cached on the Martian surface - potentially subject samples to the highest temperatures. The RSSB focused on the upper temperature limit that Mars samples should be allowed to reach. We considered 11 scientific investigations where thermal excursions may have an adverse effect on the science outcome. Those are: (T-1) organic geochemistry, (T-2) stable isotope geochemistry, (T-3) prevention of mineral hydration/dehydration and phase transformation, (T-4) retention of water, (T-5) characterization of amorphous materials, (T-6) putative Martian organisms, (T-7) oxidation/reduction reactions, (T-8) (sup 4) He thermochronometry, (T-9) radiometric dating using fission, cosmic-ray or solar-flare tracks, (T-10) analyses of trapped gasses, and (T-11) magnetic studies.

  20. Return to school after brain injury

    PubMed Central

    Hawley, C; Ward, A; Magnay, A; Mychalkiw, W

    2004-01-01

    Aims: To examine return to school and classroom performance following traumatic brain injury (TBI). Methods: This cross-sectional study set in the community comprised a group of 67 school-age children with TBI (35 mild, 13 moderate, 19 severe) and 14 uninjured matched controls. Parents and children were interviewed and children assessed at a mean of 2 years post injury. Teachers reported on academic performance and educational needs. The main measures used were classroom performance, the Children's Memory Scale (CMS), the Wechsler Intelligence Scale for Children–third edition UK (WISC-III) and the Weschler Objective Reading Dimensions (WORD). Results: One third of teachers were unaware of the TBI. On return to school, special arrangements were made for 18 children (27%). Special educational needs were identified for 16 (24%), but only six children (9%) received specialist help. Two thirds of children with TBI had difficulties with school work, half had attention/concentration problems and 26 (39%) had memory problems. Compared to other pupils in the class, one third of children with TBI were performing below average. On the CMS, one third of the severe group were impaired/borderline for immediate and delayed recall of verbal material, and over one quarter were impaired/borderline for general memory. Children in the severe group had a mean full-scale IQ significantly lower than controls. Half the TBI group had a reading age ⩾1 year below their chronological age, one third were reading ⩾2 years below their chronological age. Conclusions: Schools rely on parents to inform them about a TBI, and rarely receive information on possible long-term sequelae. At hospital discharge, health professionals should provide schools with information about TBI and possible long-term impairments, so that children returning to school receive appropriate support. PMID:14736628

  1. The Genesis Solar Wind Sample Return Mission

    NASA Technical Reports Server (NTRS)

    Wiens, Roger C.; Burnett, Donald S.; Neugebauer, Marcia; Sasaki, Chester; Sevilla, Donald; Stansbery, Eileen; Clark, Ben; Smith, Nick; Oldham, Lloyd

    1990-01-01

    The Genesis spacecraft was launched on August 8 from Cape Canaveral on a journey to become the first spacecraft to return from interplanetary space. The fifth in NASA's line of low-cost Discovery-class missions, its goal is to collect samples of solar wind and return them to Earth for detailed isotopic and elemental analysis. The spacecraft is to collect solar wind for over two years, while circling the L1 point 1.5 million km sunward of the earth, before heading back for a capsule-style re-entry in September, 2004. After parachute deployment, a mid-air helicopter recovery will be used to avoid a hard landing. The mission has been in the planning stages for over ten years. Its cost, including development, mission operations, and sample analysis, is approximately $209M. The Genesis science team, headed by principal investigator Donald Burnett of Caltech, consists of approximately 20 co-investigators from universities and science centers around the country and internationally. The spacecraft consists of a relatively flat spacecraft bus containing most of the subsystem components, situated below a sample return capsule (SRC) which holds the solar-wind collection substrates and an electrostatic solar wind concentrator. Some of the collectors are exposed throughout the collection period, for a sample of bulk solar wind, while others are exposed only to certain solar wind regimes, or types of flow. Ion and electron spectrometers feed raw data to the spacecraft control and data-handling (C&DH) unit, which determines ion moments and electron flux geometries in real time. An algorithm is used to robotically decide between interstream (IS), coronal hole (CH), and coronal mass ejection (CME) regimes, and to control deployment of the proper arrays to sample these wind regimes independently. This is the first time such a solar-wind decision algorithm has been used on board a spacecraft.

  2. Study of return rate and return time of undeliverable postal letters.

    PubMed

    Schmidt-Pokrzywniak, Andrea; Stang, Andreas

    2010-07-01

    Postal questionnaires are widely used to collect data in health research and epidemiologic studies. One problem related to mail surveys is the availability of an up-to-date and accurate list of people in the population from which to draw the sample for the survey. For the identification of incorrect postal addresses it is important that all incorrectly addressed mails are returned as undeliverable. This study examines the proportion of unreturned postal letters that were sent to incorrect addresses. We sent 339 letters to existing addresses throughout Germany, but used fictional names name of persons. Three hundred and three letters (98.2%) were returned as undeliverable. The return rates only slightly differed by layout of the envelopes, region and deliverer.

  3. The return on investment in online education.

    PubMed

    Bishop, Tana M

    2007-01-01

    In the decade since online education emerged in higher education, digital learning has become increasingly commonplace. Various models exist-from those offered fully online to others that combine traditional classroom time with some online activities. This article identifies the dominant emergent models, provides examples of their implementation across higher-education institutions, and evaluates the cost analyses conducted to date on this relatively new teaching and learning model. The ways in which we determine the return on investment depend upon the cost indicators selected, the measures of effectiveness used, and the indices by which institutions mark progress toward their educational and cost objectives.

  4. Reflection, return to practice and revalidation.

    PubMed

    Robinson, Jane

    2015-07-01

    This article explores the use of reflection and critical thinking during a return-to-practice programme, demonstrating both concepts and their value in developing insight. The aim of the article is to provide insight into a learner's reflection about nursing older people and encourage nurses to reflect and think critically about their own practice, which is a requirement of forthcoming revalidation. Lessons learned as a result of reflection must be demonstrated in order for registered nurses to revalidate. Reflection and insight gained from critical thinking can have a positive effect on individual nurses and the quality of patient care they provide.

  5. Technology for return of planetary samples, 1977

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Recent progress on the development of a basic warning system (BWS) proposed to assess the biohazard of a Mars sample returned to earth, an earth orbiting spacecraft, or to a moon base was presented. The BWS package consists of terrestrial microorganisms representing major metabolic pathways. A vital processes component of the BWS will examine the effects of a Mars sample at terrestrial atmospheric conditions while a hardy organism component will examine the effects of a Mars sample under conditions approaching those of the Martian environment. Any deleterious insult on terrestrial metabolism effected by the Mars sample could be indicated long before the sample reached earth proximity.

  6. STARDUST: An Incredulous Dream to Incredible Return

    NASA Technical Reports Server (NTRS)

    Tsou, Peter

    2006-01-01

    This viewgraph presentation reviews the Stardust mission. The goal of the mission was to return to Earth a very small part of a comet for study. The success of the mission gave us a small part of a comet to use for research into questions such as the cometary origin of water and life on earth and the formation of the solar system. The slides review the challenges, the strategy, the laboratory experiments, the instrument development, the characteristics of Aerogel, the Stardust trajectory, pictures of the samples and a listing of the firsts that were accomplished during the Stardust project.

  7. Factors affecting planned return to work after trauma: A prospective descriptive qualitative and quantitative study.

    PubMed

    Folkard, S S; Bloomfield, T D; Page, P R J; Wilson, D; Ricketts, D M; Rogers, B A

    2016-12-01

    The use of patient reported outcome measures (PROMs) in trauma is limited. The aim of this pilot study is to evaluate qualitative responses and factors affecting planned return to work following significant trauma, for which there is currently a poor evidence base. National ethical approval was obtained for routine prospective PROMs data collection, including EQ-5D, between Sept 2013 and March 2015 for trauma patients admitted to the Sussex Major Trauma Centre (n=92). 84 trauma patients disclosed their intended return to work at discharge. Additional open questions asked 'things done well' and 'things to be improved'. EQ-5D responses were valued using the time trade-off method. Statistical analysis between multiple variables was completed by ANOVA, and with categorical categories by Chi squared analysis. Only 18/68 of patients working at admission anticipated returning to work within 14days post-discharge. The injury severity scores (ISS) of those predicting return to work within two weeks and those predicting return to work longer than two weeks were 14.17 and 13.59, respectively. Increased physicality of work showed a trend towards poorer return to work outcomes, although non-significant in Chi-squared test in groups predicting return in less than or greater than two weeks (4.621, p=0.2017ns). No significant difference was demonstrated in the comparative incomes of patients with different estimated return to work outcomes (ANOVA r(2)=0.001, P=0.9590ns). EQ-5D scores were higher in those predicting return to work within two weeks when compared to greater than two weeks. Qualitative thematic content analysis of open responses was possible for 66/92 of respondents. Prominent positive themes were: care, staff, professionalism, and communication. Prominent negative themes were: food, ward response time, and communication. This pilot study highlights the importance of qualitative PROMs analysis in leading patient-driven improvements in trauma care. We provide standard

  8. The Importance of Meteorite Collections to Sample Return Missions: Past, Present, and Future Considerations

    NASA Technical Reports Server (NTRS)

    Welzenbach, L. C.; McCoy, T. J.; Glavin, D. P.; Dworkin, J. P.; Abell, P. A.

    2012-01-01

    While much of the scientific community s current attention is drawn to sample return missions, it is the existing meteorite and cosmic dust collections that both provide the paradigms to be tested by these missions and the context for interpreting the results. Recent sample returns from the Stardust and Hayabusa missions provided us with new materials and insights about our Solar System history and processes. As an example, Stardust sampled CAIs among the population of cometary grains, requiring extensive and unexpected radial mixing in the early solar nebula. This finding would not have been possible, however, without extensive studies of meteoritic CAIs that established their high-temperature, inner Solar System formation. Samples returned by Stardust also revealed the first evidence of a cometary amino acid, a discovery that would not have been possible with current in situ flight instrument technology. The Hayabusa mission provided the final evidence linking ordinary chondrites and S asteroids, a hypothesis that developed from centuries of collection and laboratory and ground-based telescopic studies. In addition to these scientific findings, studies of existing meteorite collections have defined and refined the analytical techniques essential to studying returned samples. As an example, the fortuitous fall of the Allende CV3 and Murchison CM2 chondrites within months before the return of Apollo samples allowed testing of new state-of-the-art analytical facilities. The results of those studies not only prepared us to better study lunar materials, but unanticipated discoveries changed many of our concepts about the earliest history and processes of the solar nebula. This synergy between existing collections and future space exploration is certainly not limited to sample return missions. Laboratory studies confirmed the existence of meteorites from Mars and raised the provocative possibility of preservation of ancient microbial life. The laboratory studies in

  9. A review of return-stroke models based on transmission line theory

    NASA Astrophysics Data System (ADS)

    De Conti, Alberto; Silveira, Fernando H.; Visacro, Silvério; Cardoso, Thiago C. M.

    2015-12-01

    This paper presents a review of lightning return-stroke models based on transmission line theory. The reviewed models are classified in three different categories, namely discharge-type, lumped-excitation, and parameter-estimation models. An attempt is made to address the difficulties that some models experience in reproducing directly or indirectly observable features of lightning, such as current characteristics and remote electromagnetic fields. It is argued that most of these difficulties are related to a poor discretization of the lightning channel, to inconsistencies in the calculation of per-unit-length channel parameters, to uncertainties in the representation of the upper end of the channel, and to assuming an ideal switch to connect the channel to ground in the transition from leader to return stroke. Applications of transmission line return-stroke models are also outlined.

  10. Old-Age Disability and Wealth among Return Mexican Migrants from the United States

    PubMed Central

    Wong, Rebeca; Gonzalez-Gonzalez, Cesar

    2012-01-01

    Objective To examine the old-age consequences of international migration with a focus on disability and wealth from the perspective of the origin country. Methods Analysis sample includes persons aged 60+ from the Mexican Health and Aging Study, a national survey of older-adults in Mexico in 2001. Univariate methods are used to present a comparative profile of return migrants. Multivariate models are estimated for physical disability and wealth. Results Gender differences are profound. Return migrant women are more likely to be disabled while men are wealthier than comparable older adults in Mexico. Discussion Compared to current older adults, younger cohorts of Mexico-U.S. migrants increasingly include women, and more migrants seem likely to remain in the United States rather than return, thus more research will be needed on the old-age conditions of migrants in both countries. PMID:20876848

  11. Quantitative Planetary Protection for Sample Return from Ocean Worlds

    NASA Astrophysics Data System (ADS)

    Neveu, Marc; Takano, Yoshinori; Porco, Carolyn; McKay, Christopher P.; Glavin, Daniel; Anbar, Ariel; Sherwood, Brent; Yano, Hajime

    2016-07-01

    Volcanism on ocean worlds [1,2] facilitates ocean sample return missions, enabling uniquely flexible, sensitive, and specific laboratory analyses on Earth to study how far chemistry has evolved in presumably habitable oceans [3,4]. Such mission concepts have yet to quantitatively address planetary protection (PP) for ocean worlds [3,4]. These harbor liquid water [5,6], metabolically useful energy [7], and organic matter to support life [8]. Ocean temperatures may not exceed the limit for life as we know it [9,10], they are shielded from exogenic radiation by kilometers of ice, and their material has likely not been naturally exchanged with Earth [11]. The above factors would place sample return missions in Cat. V - Restricted Earth Return [12,13]. Forward PP requirements for Europa [13] and other ocean worlds [14] require that the probability of "introduction of a single viable terrestrial microorganism into a liquid-water environment" be lower than 10 ^{-4}. This probability should be estimated from (F1) "bioburden at launch," (F2) "cruise survival for contaminating organisms," (F3) "organism survival in the radiation environment adjacent to the target," (F4) "the probability of encountering […] the target," (F5) "the probability of surviving landing/impact on the target," (F6) "mechanisms and timescales of transport to the subsurface," and (F7) "survival […] after subsurface transfer" [13,14]. The compliance of specific designs of known cost could be evaluated from measurements of molecular contaminants as robust and universal proxies for microbial particulates [15] (F1); known microbial radiation tolerance [16] and planetary radiation budgets [17] (F2-F3); trajectory design (F4); projected impact velocities [18] (F5); ice transport timescales [19] (F6), and biomass growth rates in ice [20] (F7). In contrast, current backward PP requirements are only qualitative. Current policy [13,15] prohibits "destructive impact upon return," and requires that (B1) "unless

  12. An Investigation of Domestic Approval Plan Return Rates by Academic Subjects before and after Subject Reprofiling at a Medium-Sized Academic Library.

    ERIC Educational Resources Information Center

    Herbert, Ida L.

    Approval plans are widely used in academic libraries to acquire current books soon after publication without time-consuming, costly title-by-title ordering. However, return rates of unselected books to the approval plan vendor are sometimes unacceptably high. Wright State University Library attempted to moderate their high approval return rates by…

  13. 26 CFR 301.6103(c)-1 - Disclosure of returns and return information to designee of taxpayer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... telephone conversation with Internal Revenue Service officials. (iii) As long as the requirements of this... telephone conversation, for disclosures of returns and return information to be made to the other person. (3... paragraph, common data means information reflected on the Federal return required by State law to...

  14. 26 CFR 301.6103(c)-1 - Disclosure of returns and return information to designee of taxpayer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... telephone conversation with Internal Revenue Service officials. (iii) As long as the requirements of this... telephone conversation, for disclosures of returns and return information to be made to the other person. (3... paragraph, common data means information reflected on the Federal return required by State law to...

  15. 26 CFR 301.6103(c)-1 - Disclosure of returns and return information to designee of taxpayer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... telephone conversation with Internal Revenue Service officials. (iii) As long as the requirements of this... telephone conversation, for disclosures of returns and return information to be made to the other person. (3... paragraph, common data means information reflected on the Federal return required by State law to...

  16. 26 CFR 301.6103(c)-1 - Disclosure of returns and return information to designee of taxpayer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... telephone conversation with Internal Revenue Service officials. (iii) As long as the requirements of this... telephone conversation, for disclosures of returns and return information to be made to the other person. (3... paragraph, common data means information reflected on the Federal return required by State law to...

  17. Return times of polynomials as meta-Fibonacci numbers

    NASA Astrophysics Data System (ADS)

    Emerson, Nathaniel D.

    We consider generalized closest return times of a complex polynomial of degree at least two. Most previous studies on this subject have focused on the properties of polynomials with particular return times, especially the Fibonacci numbers. We study the general form of these closest return times. The main result of this paper is that these closest return times are meta-Fibonacci numbers. In particular, this result applies to the return times of a principal nest of a polynomial. Furthermore, we show that an analogous result holds in a tree with dynamics that is associated with a polynomial.

  18. Temperature distribution and evolution characteristic in lightning return stroke channel

    NASA Astrophysics Data System (ADS)

    Mu, Yali; Yuan, Ping; Wang, Xuejuan; Dong, Caixia

    2016-07-01

    According to the time-resolved spectra of four lightning return strokes, the temperatures of arc core channel and the peripheral optical channel surrounding the arc core are investigated by different methods; the temperature distribution along the radial direction of channel on the peak current stage is discussed. The results show that a temperature gradient is formed along the radial direction of channel during the discharge process. With the increasing of the radius, the temperature decreases gradually. The temperature of arc core channel is about 4000-5000 K higher than that of the peripheral optical channel. The time evolution of channel temperature shows that the falling of the temperature is very slow compared with the decreasing of the current after their peak values. After the peak current, the channel temperature is still maintained at around 20,000 K up to 200-400 μ s . The heat effect resulting from such a long-time high temperature is the main source of most direct lightning disasters.

  19. Work-Related Factors Considered by Sickness-Absent Employees When Estimating Timeframes for Returning to Work

    PubMed Central

    Choi, YoonSun

    2016-01-01

    Introduction Work-related factors have been found to be influential in shaping a number of return-to-work outcomes including return-to-work expectations. Based on the idea that work-related factors have the potential for modification through workplace-based initiatives, this study involved a detailed examination of work-related factors referenced by workers as being taken into consideration when estimating timeframes for returning to work. Methods Focus groups were conducted with 30 employees, currently off work (≤ 3 months) due to a musculoskeletal condition. During the focus groups, participants wrote and spoke about the factors that they considered when forming their expectations for returning to work. Data were subjected to thematic content analysis. Results Discussions revealed that participants’ considerations tended to differ depending on whether or not they had a job to return to. Those with jobs (n = 23) referenced specific influences such as working relationships, accommodations, physical and practical limitations, as well as concerns about their ability to do their job. Those without a job to return to (n = 7) talked about the ways they would go about finding work, and how long they thought this would take. Both groups mentioned the influence of wanting to find the “right” job, retraining and being limited due to the need for income. Conclusion Findings indicate that employees reference numerous work-related factors when estimating their timeframes for returning to work, and that many of these have been previously identified as relating to other return-to-work outcomes. Findings suggest the potential to improve return-to-work expectation through addressing work-related influences, and helping people work through the tasks they need to complete in order to move forward in the return-to-work process. PMID:27706194

  20. Note on a modified return period scale for upper-truncated unbounded flood distributions

    NASA Astrophysics Data System (ADS)

    Bardsley, Earl

    2017-01-01

    Probability distributions unbounded to the right often give good fits to annual discharge maxima. However, all hydrological processes are in reality constrained by physical upper limits, though not necessarily well defined. A result of this contradiction is that for sufficiently small exceedance probabilities the unbounded distributions anticipate flood magnitudes which are impossibly large. This raises the question of whether displayed return period scales should, as is current practice, have some given number of years, such as 500 years, as the terminating rightmost tick-point. This carries the implication that the scale might be extended indefinitely to the right with a corresponding indefinite increase in flood magnitude. An alternative, suggested here, is to introduce a sufficiently high upper truncation point to the flood distribution and modify the return period scale accordingly. The rightmost tick-mark then becomes infinity, corresponding to the upper truncation point discharge. The truncation point is likely to be set as being above any physical upper bound and the return period scale will change only slightly over all practical return periods of operational interest. The rightmost infinity tick point is therefore proposed, not as an operational measure, but rather to signal in flood plots that the return period scale does not extend indefinitely to the right.

  1. Project Hyreus: Mars Sample Return Mission Utilizing in Situ Propellant Production

    NASA Technical Reports Server (NTRS)

    Bruckner, A. P.; Thill, Brian; Abrego, Anita; Koch, Amber; Kruse, Ross; Nicholson, Heather; Nill, Laurie; Schubert, Heidi; Schug, Eric; Smith, Brian

    1993-01-01

    Project Hyreus is an unmanned Mars sample return mission that utilizes propellants manufactured in situ from the Martian atmosphere for the return voyage. A key goal of the mission is to demonstrate the considerable benefits of using indigenous resources and to test the viability of this approach as a precursor to manned Mars missions. The techniques, materials, and equipment used in Project Hyreus represent those that are currently available or that could be developed and readied in time for the proposed launch date in 2003. Project Hyreus includes such features as a Mars-orbiting satellite equipped with ground-penetrating radar, a large rover capable of sample gathering and detailed surface investigations, and a planetary science array to perform on-site research before samples are returned to Earth. Project Hyreus calls for the Mars Landing Vehicle to land in the Mangala Valles region of Mars, where it will remain for approximately 1.5 years. Methane and oxygen propellant for the Earth return voyage will be produced using carbon dioxide from the Martian atmosphere and a small supply of hydrogen brought from Earth. This process is key to returning a large Martian sample to Earth with a single Earth launch.

  2. Going home after Hurricane Katrina: Determinants of return migration and changes in affected areas.

    PubMed

    Groen, Jeffrey A; Polivka, Anne E

    2010-11-01

    This article examines the decision of Hurricane Katrina evacuees to return to their pre-Katrina areas and documents how the composition of the Katrina-affected region changed over time. Using data from the Current Population Survey, we show that an evacuee's age, family income, and the severity of damage in an evacuee's county of origin are important determinants of whether an evacuee returned during the first year after the storm. Blacks were less likely to return than whites, but this difference is primarily related to the geographical pattern of storm damage rather than to race per se. The difference between the composition of evacuees who returned and the composition of evacuees who did not return is the primary force behind changes in the composition of the affected areas in the first two years after the storm. Katrina is associated with substantial shifts in the racial composition of the affected areas (namely, a decrease in the percentage of residents who are black) and an increasing presence of Hispanics. Katrina is also associated with an increase in the percentage of older residents, a decrease in the percentage of residents with low income/education, and an increase in the percentage of residents with high income/education.

  3. Return-to-Play Recommendations After Cervical, Thoracic, and Lumbar Spine Injuries

    PubMed Central

    Huang, Philip; Anissipour, Alireza; McGee, William; Lemak, Lawrence

    2016-01-01

    Context: Currently, there is a national focus on establishing and disseminating standardized guidelines for return to play for athletes at all levels of competition. As more data become available, protocols and guidelines are being refined and implemented to assist physicians, coaches, trainers, players, and parents in making decisions about return to play. To date, no standardized criteria for returning to play exist for injuries to the spine. Evidence Acquisition: Electronic databases including PubMed and MEDLINE and professional orthopaedic, neurosurgical, and spine organizational websites were reviewed between 1980 and 2015. Study Design: Clinical review. Level of Evidence: Level 4. Results: Although clinical guidelines have been published for return to play after spine injury, they are almost exclusively derived from expert opinion and clinical experience rather than from well-designed studies. Furthermore, recommendations differ and vary depending on anatomic location, type of sport, and surgery performed. Conclusion: Despite a lack of consensus and specific recommendations, there is universal agreement that athletes should be pain free, completely neurologically intact, and have full strength and range of motion before returning to play after spinal injury. PMID:26502187

  4. Characteristics of the horizontal electric field associated with nearby lightning return strokes

    NASA Astrophysics Data System (ADS)

    Yu, J. L.; Fan, Y. D.; Wang, J. G.; Qi, R. H.; Zhou, M.; Cai, L.; Cui, M. J.; Yuan, Z. J.

    2017-02-01

    There exists inherent difficulty in measuring the horizontal electric field (Er) associated with lightning return strokes due to the overshadowing effect of the vertical electric field component, not much progress in Er measurements were observed until now. In order to study the characteristics of Er associated with nearby lightning return strokes, the modified transmission-line model with linear current decay with height (MTLL) return stroke model and Finite Difference Time Domain (FDTD) method were used to calculate Er for 12 observation points with different distances (20, 50 100, and 200 m) away from the lightning channel and different heights (0, 10, and 20 m) above ground. Four characteristic parameters, namely, the return-stroke speed (v), the total length of the return stroke channel (H), the ground relative permittivity (ε) and the ground conductivity (σ), were considered. Results show that the polarity of Er changes between the ground level and the space. The influence intensity rank of the four characteristic parameters on Er at ground level is: σ>v>ε>H. The influence of the characteristic parameters on Er are more important for v≤0.6c, H≤6000 m and σ≤2.5×10-3S/m.

  5. Estimation of return periods of multiple losses per winter associated with historical windstorm series over Germany

    NASA Astrophysics Data System (ADS)

    Karremann, Melanie; Pinto, Joaquim G.; von Bomhard, Philipp; Klawa, Matthias

    2014-05-01

    During the last decades, several windstorm series hit Western Europe leading to large cumulative economic losses. Such storm series are an example of serial clustering of extreme cyclones and present a considerable risk for the insurance industry. Here, clustering of events and return periods of storm series for Germany are quantified based on potential losses using empirical models. Two reanalysis datasets and observations from 123 German Weather Service stations are considered for the winters 1981/1982 to 2010/2011. Based on these datasets, histograms of events exceeding selected return levels (1-, 2- and 5-year) are derived. Return periods of historical storm series are estimated based on the Poisson and the negative Binomial distribution. About 4680 years of global circulation model simulations forced with current climate conditions are analysed to provide a better assessment of historical return periods. Estimations differ between the considered distributions. Except for frequent and weak events, the return period estimates obtained with the Poisson distribution clearly deviate from empirical data. This clearly documents overdispersion in the loss data, thus indicating the clustering of potential loss events. Better assessments are achieved for the negative Binomial distribution, e.g. 34 to 53 years for the storm series like 1989/1990. The overdispersion (clustering) of potential loss events clearly states the importance of an adequate risk assessment of multiple events per winter for economical applications.

  6. Project Hyreus: Mars sample return mission utilizing in situ propellant production

    NASA Technical Reports Server (NTRS)

    Abrego, Anita; Bair, Chris; Hink, Anthony; Kim, Jae; Koch, Amber; Kruse, Ross; Ngo, Dung; Nicholson, Heather; Nill, Laurie; Perras, Craig

    1993-01-01

    Project Hyreus is an unmanned Mars sample return mission that utilizes propellants manufactured in situ from the Martian atmosphere for the return voyage. A key goal of the mission is to demonstrate the considerable benefits of using indigenous resources and to test the viability of this approach as a precursor to manned Mars missions. The techniques, materials, and equipment used in Project Hyreus represent those that are currently available or that could be developed and readied in time for the proposed launch date in 2003. Project Hyreus includes such features as a Mars-orbiting satellite equipped with ground-penetrating radar, a large rover capable of sample gathering and detailed surface investigations, and a planetary science array to perform on-site research before samples are returned to Earth. Project Hyreus calls for the Mars Landing Vehicle to land in the Mangala Valles region of Mars, where it will remain for approximately 1.5 years. Methane and oxygen propellant for the Earth return voyage will be produced using carbon dioxide from the Martian atmosphere and a small supply of hydrogen brought from Earth. This process is key to returning a large Martian sample to Earth with a single Earth launch.

  7. Mars Double-Flyby Free Returns

    NASA Technical Reports Server (NTRS)

    Jesick, Mark

    2015-01-01

    A subset of Earth-originating Mars double-flyby ballistic trajectories is documented. The subset consists of those trajectories that, after the first Mars flyby, perform a half-revolution transfer with Mars before returning to Earth. This class of free returns is useful for both human and robotic Mars missions because of its low geocentric energy at departure and arrival, and because of its extended stay time in the vicinity of Mars. Ballistic opportunities are documented over Earth departure dates ranging from 2015 through 2100. The mission is viable over three or four consecutive Mars synodic periods and unavailable for the next four, with the pattern repeating approximately every 15 years. Over the remainder of the century, a minimum Earth departure hyperbolic excess speed of 3.16 km/s, a minimum Earth atmospheric entry speed of 11.47 km/s, and a minimum flight time of 904 days are observed. The algorithm used to construct these trajectories is presented along with several examples.

  8. A wavelet based investigation of long memory in stock returns

    NASA Astrophysics Data System (ADS)

    Tan, Pei P.; Galagedera, Don U. A.; Maharaj, Elizabeth A.

    2012-04-01

    Using a wavelet-based maximum likelihood fractional integration estimator, we test long memory (return predictability) in the returns at the market, industry and firm level. In an analysis of emerging market daily returns over the full sample period, we find that long-memory is not present and in approximately twenty percent of 175 stocks there is evidence of long memory. The absence of long memory in the market returns may be a consequence of contemporaneous aggregation of stock returns. However, when the analysis is carried out with rolling windows evidence of long memory is observed in certain time frames. These results are largely consistent with that of detrended fluctuation analysis. A test of firm-level information in explaining stock return predictability using a logistic regression model reveal that returns of large firms are more likely to possess long memory feature than in the returns of small firms. There is no evidence to suggest that turnover, earnings per share, book-to-market ratio, systematic risk and abnormal return with respect to the market model is associated with return predictability. However, degree of long-range dependence appears to be associated positively with earnings per share, systematic risk and abnormal return and negatively with book-to-market ratio.

  9. A Mars Sample Return Sample Handling System

    NASA Technical Reports Server (NTRS)

    Wilson, David; Stroker, Carol

    2013-01-01

    We present a sample handling system, a subsystem of the proposed Dragon landed Mars Sample Return (MSR) mission [1], that can return to Earth orbit a significant mass of frozen Mars samples potentially consisting of: rock cores, subsurface drilled rock and ice cuttings, pebble sized rocks, and soil scoops. The sample collection, storage, retrieval and packaging assumptions and concepts in this study are applicable for the NASA's MPPG MSR mission architecture options [2]. Our study assumes a predecessor rover mission collects samples for return to Earth to address questions on: past life, climate change, water history, age dating, understanding Mars interior evolution [3], and, human safety and in-situ resource utilization. Hence the rover will have "integrated priorities for rock sampling" [3] that cover collection of subaqueous or hydrothermal sediments, low-temperature fluidaltered rocks, unaltered igneous rocks, regolith and atmosphere samples. Samples could include: drilled rock cores, alluvial and fluvial deposits, subsurface ice and soils, clays, sulfates, salts including perchlorates, aeolian deposits, and concretions. Thus samples will have a broad range of bulk densities, and require for Earth based analysis where practical: in-situ characterization, management of degradation such as perchlorate deliquescence and volatile release, and contamination management. We propose to adopt a sample container with a set of cups each with a sample from a specific location. We considered two sample cups sizes: (1) a small cup sized for samples matching those submitted to in-situ characterization instruments, and, (2) a larger cup for 100 mm rock cores [4] and pebble sized rocks, thus providing diverse samples and optimizing the MSR sample mass payload fraction for a given payload volume. We minimize sample degradation by keeping them frozen in the MSR payload sample canister using Peltier chip cooling. The cups are sealed by interference fitted heat activated memory

  10. Exiting and Returning to the Parental Home for Boomerang Kids

    PubMed Central

    Sandberg-Thoma, Sara E.; Snyder, Anastasia R.; Jang, Bohyun Joy

    2015-01-01

    Young adults commonly exit from and return to the parental home, yet few studies have examined the motivation behind these exits and returns using a life course framework. Using data from the National Longitudinal Survey of Youth 1997, the authors examined associations between mental health problems and economic characteristics and exits from (n = 8,162), and returns to (n = 6,530), the parental home during the transition to adulthood. The average age of the respondents was 24 years. The authors found evidence that mental health and economic characteristics were related to home leaving and returning. Emotional distress was associated with earlier exits from, and returns to, the parental home; alcohol problems were associated with earlier returns to the parental home. The findings regarding economic resources were unexpectedly mixed. Greater economic resources were linked to delayed exits from, and earlier returns to, the parental home. The implications of these findings for young adults are discussed. PMID:26023244

  11. The Extinction and Return of Fear of Public Speaking.

    PubMed

    Laborda, Mario A; Schofield, Casey A; Johnson, Emily M; Schubert, Jessica R; George-Denn, Daniel; Coles, Meredith E; Miller, Ralph R

    2016-11-01

    Prior studies indicate extinguished fear often partially returns when participants are later tested outside the extinction context. Cues carried from the extinction context to the test context sometimes reduce return of fear, but it is unclear whether such extinction cues (ECs) reduce return of fear of public speaking. Here we assessed return of fear of public speaking, and whether either of two types of ECs can attenuate it. Participants gave speeches of increasing difficulty during an exposure practice session and were tested 2 days later in a different context. Testing occurred in the presence of physical ECs, after mentally rehearsing the exposure session, or without either reminder. Practice reduced fear of public speaking, but fear partially returned at test. Neither physical nor mental ECs reduced partial return of fear of public speaking. The return of extinguished fear of public speaking, although small, was reliable, but not appreciably sensitive to presence of ECs.

  12. Impact of the salt leakage through the Indian-Atlantic ocean gateway on the Atlantic MOC

    NASA Astrophysics Data System (ADS)

    Marino, G.; Zahn, R.; Ziveri, P.; Ziegler, M.; Hall, I. R.; Elderfield, H.

    2012-04-01

    Freshwater perturbation in the northern North Atlantic exerts a strong influence on the stability of the Atlantic meridional overturning circulation (AMOC) with potentially severe impacts on the regional and global climates. The occurrence of ice rafted detritus (IRD) in the glacial sediments of the North Atlantic testifies to past episodes of Laurentide ice sheet surging that also coincided with AMOC curtailments and prominent climate deterioration in the Northeast Atlantic and Western Europe. The equally abrupt warming shifts observed in Greenland ice core and North Atlantic sediment core records that characterize the end of each IRD event have been related to the rapid resumption of AMOC and its associated heat transport. The hysteresis response, under glacial boundary conditions, of the AMOC to freshwater forcing suggests that a reduction in this forcing may have been sufficient to trigger the rapid AMOC resumptions revealed by several palaeoceanographic records. But recent modelling studies allude to the potential importance of a salt surplus, originating in the Indian Ocean and transported to the South Atlantic via the Agulhas leakage, that may have acted as a positive feedback on the AMOC strengthening. This possibility, however, has yet to be adequately tested with palaeoproxy reconstructions. We present a suite of multi-centennial-scale palaeoceanographic records spanning a full glacial cycle from the Southwest African margin and Agulhas Plateau that have been generated as part of the EU Marie Curie GATEWAYS project. The sediment cores are positioned such that they monitor the leakage of Agulhas water into the Atlantic and the Agulhas Return Current that straddles the South Atlantic subtropical front on its way to the Indian Ocean. Paired Mg/Ca-δ18O analyses on the planktonic foraminifera Globigerinoides ruber and Globigerina bulloides reveal millennial-scale surface ocean temperature and salinity changes at the core sites that reflect recurrent

  13. Stray current characteristics of DC transit systems

    SciTech Connect

    Moody, K.J. . Transportation Technologies Div.)

    1994-06-01

    The re-emergence and rapid growth of use of DC-powered transit systems around the world has led to the adaptation of three distinct operational modes: grounded, ungrounded, and diode grounded. Each of these modes causes widely varying amounts of stray current in systems using the running rails for negative return current. The advantages of each operational mode and the possible stray current effects on transit and adjacent utility structures are discussed.

  14. Healthier before they migrate, less healthy when they return? The health of returned migrants in Mexico

    PubMed Central

    Ullmann, S. Heidi; Goldman, Noreen; Massey, Douglas S.

    2011-01-01

    Over the course of the 20th century, Mexico-U.S. migration has emerged as an important facet of both countries, with far reaching economic and social impacts. The health of Mexican immigrants in the U.S. has been well studied, but relatively less is known about the health of returned migrants to Mexico. The objectives of this paper are twofold. Relying on health data pertaining to two stages of the life course, early life health (pre-migration) and adult health (post-migration) from the Mexican Migration Project gathered between 2007 and 2009, we aim to assess disparities in adult health status between male returned migrants and male non-migrants in Mexico, accounting for their potentially different early life health profiles. While we find evidence that returned migrants had more favorable early life health, the results for adult health are more complex. Returned migrants have a higher prevalence of heart disease, emotional/psychiatric disorders, obesity, and smoking than non-migrants but no differences are found in self-rated health, diabetes, or hypertension. PMID:21729820

  15. Aerothermodynamic environments for Mars entry, Mars return, and lunar return aerobraking missions

    NASA Technical Reports Server (NTRS)

    Rochelle, W. C.; Bouslog, S. A.; Ting, P. C.; Curry, D. M.

    1990-01-01

    The aeroheating environments to vehicles undergoing Mars aerocapture, earth aerocapture from Mars, and earth aerocapture from the moon are presented. An engineering approach for the analysis of various types of vehicles and trajectories was taken, rather than performing a benchmark computation for a specific point at a selected time point in a trajectory. The radiation into Mars using the Mars Rover Sample Return (MRSR) 2-ft nose radius bionic remains a small contributor of heating for 6 to 10 km/sec; however, at 12 km/sec it becomes comparable with the convection. For earth aerocapture, returning from Mars, peak radiation for the MRSR SRC is only 25 percent of the peak convection for the 12-km/sec trajectory. However, when large vehicles are considered with this trajectory, peak radiation can become 2 to 4 times higher than the peak convection. For both Mars entry and return, a partially ablative Thermal Protection System (TPS) would be required, but for Lunar Transfer Vehicle return an all-reusable TPS can be used.

  16. Looking back at Waldo: oculomotor inhibition of return does not prevent return fixations.

    PubMed

    Smith, Tim J; Henderson, John M

    2011-01-04

    Inhibition of Return (IOR) is a difficulty in processing stimuli presented at recently attended locations. IOR is widely believed to facilitate foraging of a visual scene by decreasing the probability that gaze will return to previously fixated locations. However, there is a lack of clear evidence in support of the foraging facilitator hypothesis during scene search. The original R. M. Klein and W. J. MacInnes' (1999) Where's Waldo study reported a forward bias in the distribution of fixations that was taken as evidence for the foraging facilitator hypothesis. The present study was designed to replicate R. M. Klein and W. J. MacInnes' (1999) but include detailed analysis of fixation distributions in order to test the precise predictions of the foraging facilitator hypothesis. The results indicate that latencies of saccades returning to 1-back (and possibly 2-back) locations during visual search are elevated. However, there is no evidence that the probability of returning to these locations is significantly less than control locations. Eye movement behavior during search of visual scenes does not support the view that IOR facilitates foraging.

  17. Football injuries: current concepts.

    PubMed

    Olson, David E; Sikka, Robby Singh; Hamilton, Abigail; Krohn, Austin

    2011-01-01

    Football is one of the most popular sports in the United States and is the leading cause of sports-related injury. A large focus in recent years has been on concussions, sudden cardiac death, and heat illness, all thought to be largely preventable health issues in the young athlete. Injury prevention through better understanding of injury mechanisms, education, proper equipment, and practice techniques and preseason screening may aid in reducing the number of injuries. Proper management of on-field injuries and health emergencies can reduce the morbidity associated with these injuries and may lead to faster return to play and reduced risk of future injury. This article reviews current concepts surrounding frequently seen football-related injuries.

  18. The Gulliver sample return mission to Deimos

    NASA Astrophysics Data System (ADS)

    Britt, D. T.; Robinson, M.; Gulliver Team

    The Martian moon Deimos presents a unique opportunity for a sample return mission. Deimos is spectrally analogous to type D asteroids, which are thought to be composed of highly primitive carbonaceous material that originated in the outer asteroid belt. It also is in orbit around Mars and has been accumulating material ejected from the Martian surface ever since the earliest periods of Martian history, over 4.4 Gyrs ago. There are a number of factors that make sample return from Deimos extremely attractive. It is Better: Deimos is a repository for two kinds of extremely significant and scientifically exciting ancient samples: (1) Primitive spectral D-type material that may have accreted in the outer asteroid belt and Trojan swarm. This material samples the composition of solar nebula well outside the zone of terrestrial planets and provides a direct sample of primitive material so common past 3 AU but so uncommon in the meteorite collection. (2) Ancient Mars, which could include the full range of Martian crustal and upper mantle material from the early differentiation and crustal-forming epoch as well as samples from the era of high volatile flux, thick atmosphere, and possible surface water. The Martian material on Deimos would be dominated by ejecta from the ancient crust of Mars, delivered during the Noachian Period of basin-forming impacts and heavy bombardment. It is Closer: Compared to other primitive D-type asteroids, Deimos is by far the most accessible. Because of its orbit around Mars, Deimos is far closer than any other D asteroid. It is Safer: Deimos is also by far the safest small body for sample return yet imaged. It is an order of magnitude less rocky than Eros and the NEAR-Shoemaker mission succeeded in landing on Eros with a spacecraft not designed for landing and proximity maneuvering. Because of Viking imagery we already know a great deal about the surface roughness of Deimos. It is known to be very smooth and have moderate topography and

  19. Orbiter Return-To-Flight Entry Aeroheating

    NASA Technical Reports Server (NTRS)

    Campbell, Charles H.; Anderson, Brian; Bourland, Gary; Bouslog, Stan; Cassady, Amy; Horvath, Tom; Berry, Scott A.; Gnoffo, Peter; Wood, Bill; Reuther, James; Driver, Dave; Chao, Dennis

    2006-01-01

    The Columbia accident on February 1, 2003 began an unprecedented level of effort within the hypersonic aerothermodynamic community to support the Space Shuttle Program. During the approximately six month time frame of the primary Columbia Accident Investigation Board activity, many technical disciplines were involved in a concerted effort to reconstruct the last moments of the Columbia and her crew, and understand the critical events that led to that loss. Significant contributions to the CAIB activity were made by the hypersonic aerothermodynamic community(REF CAIB) in understanding the re-entry environments that led to the propagation of an ascent foam induced wing leading edge damage to a subsequent breech of the wing spar of Columbia, and the subsequent breakup of the vehicle. A core of the NASA hypersonic aerothermodynamics team that was involved in the CAIB investigation has been combined with the United Space Alliance and Boeing Orbiter engineering team in order to position the Space Shuttle Program with a process to perform in-flight Thermal Protection System damage assessments. This damage assessment process is now part of the baselined plan for Shuttle support, and is a direct out-growth of the Columbia accident and NASAs response. Multiple re-entry aeroheating tools are involved in this damage assessment process, many of which have been developed during the Return To Flight activity. In addition, because these aeroheating tools are part of an overall damage assessment process that also involves the thermal and stress analyses community, in addition to a much broader mission support team, an integrated process for performing the damage assessment activities has been developed by the Space Shuttle Program and the Orbiter engineering community. Several subsets of activity in the Orbiter aeroheating communities support to the Return To Flight effort have been described in previous publications (CFD?, Cavity Heating? Any BLT? Grid Generation?). This work will

  20. Quick returns and night work as predictors of sleep quality, fatigue, work-family balance and satisfaction with work hours.

    PubMed

    Dahlgren, Anna; Tucker, Philip; Gustavsson, Petter; Rudman, Ann

    2016-01-01

    Quick returns (intervals of <11 h between the end of one shift and the start of the next) are associated with short sleeps and fatigue on the subsequent shift. Recent evidence suggests that shift workers regard quick returns as being more problematic than night work. The current study explored quick returns and night work in terms of their impact on sleep, unwinding, recovery, exhaustion, satisfaction with work hours and work-family interference. Data from the 2006 cohort of Swedish nursing students within the national Longitudinal Analysis of Nursing Education (LANE) study were analysed (N = 1459). Respondents completed a questionnaire prior to graduation (response rate 69.2%) and 3 years after graduation (65.9%). The analyses examined associations between frequency of quick returns and night work and measures taken in year three, while adjusting for confounding factors (in year three and prior graduation). Frequency of quick returns was a significant predictor of poor sleep quality, short sleeps, unwinding, exhaustion, satisfaction with work hours and work-to-family interference, with higher frequency predicting more negative outcomes. Quick returns did not predict recovery after rest days. Frequency of night work did not predict any of the outcomes. In conclusion, quick returns were an important determinant of sleep, recovery and wellbeing, whereas night work did not show such an association.