Sample records for self-limiting power excursion

  1. Burn Control Mechanisms in Tokamaks

    NASA Astrophysics Data System (ADS)

    Hill, M. A.; Stacey, W. M.

    2015-11-01

    Burn control and passive safety in accident scenarios will be an important design consideration in future tokamak reactors, in particular fusion-fission hybrid reactors, e.g. the Subcritical Advanced Burner Reactor. We are developing a burning plasma dynamics code to explore various aspects of burn control, with the intent to identify feedback mechanisms that would prevent power excursions. This code solves the coupled set of global density and temperature equations, using scaling relations from experimental fits. Predictions of densities and temperatures have been benchmarked against DIII-D data. We are examining several potential feedback mechanisms to limit power excursions: i) ion-orbit loss, ii) thermal instability density limits, iii) MHD instability limits, iv) the degradation of alpha-particle confinement, v) modifications to the radial current profile, vi) ``divertor choking'' and vii) Type 1 ELMs. Work supported by the US DOE under DE-FG02-00ER54538, DE-FC02-04ER54698.

  2. Approximate scaling properties of RNA free energy landscapes

    NASA Technical Reports Server (NTRS)

    Baskaran, S.; Stadler, P. F.; Schuster, P.

    1996-01-01

    RNA free energy landscapes are analysed by means of "time-series" that are obtained from random walks restricted to excursion sets. The power spectra, the scaling of the jump size distribution, and the scaling of the curve length measured with different yard stick lengths are used to describe the structure of these "time series". Although they are stationary by construction, we find that their local behavior is consistent with both AR(1) and self-affine processes. Random walks confined to excursion sets (i.e., with the restriction that the fitness value exceeds a certain threshold at each step) exhibit essentially the same statistics as free random walks. We find that an AR(1) time series is in general approximately self-affine on timescales up to approximately the correlation length. We present an empirical relation between the correlation parameter rho of the AR(1) model and the exponents characterizing self-affinity.

  3. Estimates of the effectiveness of automatic control in alleviating wake vortex induced roll excursions

    NASA Technical Reports Server (NTRS)

    Tinling, B. E.

    1977-01-01

    Estimates of the effectiveness of a model following type control system in reducing the roll excursion due to a wake vortex encounter were obtained from single degree of freedom computations with inputs derived from the results of wind tunnel, flight, and simulation experiments. The analysis indicates that the control power commanded by the automatic system must be roughly equal to the vortex induced roll acceleration if effective limiting of the maximum bank angle is to be achieved.

  4. The Role of the Intellectual--An Excursion into Self-Criticism.

    ERIC Educational Resources Information Center

    Galtung, Johan

    2002-01-01

    Distinguishes two roles of the intellectual, one in search of truth and the other in search of power. Sees the latter as closely related to the emergence of nation states and centralized capitalism and as problematic when it results in a small elite expropriating the challenges that should belong to others. (EV)

  5. Consistency of a lumbar movement pattern across functional activities in people with low back pain.

    PubMed

    Marich, Andrej V; Hwang, Ching-Ting; Salsich, Gretchen B; Lang, Catherine E; Van Dillen, Linda R

    2017-05-01

    Limitation in function is a primary reason people with low back pain seek medical treatment. Specific lumbar movement patterns, repeated throughout the day, have been proposed to contribute to the development and course of low back pain. Varying the demands of a functional activity test may provide some insight into whether people display consistent lumbar movement patterns during functional activities. Our purpose was to examine the consistency of the lumbar movement pattern during variations of a functional activity test in people with low back pain and back-healthy people. 16 back-healthy adults and 32 people with low back pain participated. Low back pain participants were classified based on the level of self-reported functional limitations. Participants performed 5 different conditions of a functional activity test. Lumbar excursion in the early phase of movement was examined. The association between functional limitations and early phase lumbar excursion for each test condition was examined. People with low back pain and high levels of functional limitation demonstrated a consistent pattern of greater early phase lumbar excursion across test conditions (p<0.05). For each test condition, the amount of early phase lumbar excursion was associated with functional limitation (r=0.28-0.62). Our research provides preliminary evidence that people with low back pain adopt consistent movement patterns during the performance of functional activities. Our findings indicate that the lumbar spine consistently moves more readily into its available range in people with low back pain and high levels of functional limitation. How the lumbar spine moves during a functional activity may contribute to functional limitations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Relationship of medial gastrocnemius relative fascicle excursion and ankle joint power and work performance during gait in typically developing children: A cross-sectional study.

    PubMed

    Martín Lorenzo, Teresa; Albi Rodríguez, Gustavo; Rocon, Eduardo; Martínez Caballero, Ignacio; Lerma Lara, Sergio

    2017-07-01

    Muscle fascicles lengthen in response to chronic passive stretch through in-series sarcomere addition in order to maintain an optimum sarcomere length. In turn, the muscles' force generating capacity, maximum excursion, and contraction velocity is enhanced. Thus, longer fascicles suggest a greater capacity to develop joint power and work. However, static fascicle length measurements may not be taking sarcomere length differences into account. Thus, we considered relative fascicle excursions through passive ankle dorsiflexion may better correlate with the capacity to generate joint power and work than fascicle length. Therefore, the aim of the present study was to determine if medial gastrocnemius relative fascicle excursions correlate with ankle joint power and work generation during gait in typically developing children. A sample of typically developing children (n = 10) were recruited for this study and data analysis was carried out on 20 legs. Medial gastrocnemius relative fascicle excursion from resting joint angle to maximum dorsiflexion was estimated from trigonometric relations of medial gastrocnemius pennation angle and thickness obtained from B-mode real-time ultrasonography. Furthermore, a three-dimensional motion capture system was used to obtain ankle joint work and power during the stance phase of gait. Significant correlations were found between relative fascicle excursion and peak power absorption (-) r(14) = -0.61, P = .012 accounting for 31% variability, positive work r(18) = 0.56, P = .021 accounting for 31% variability, and late stance positive work r(15) = 0.51, P = .037 accounting for 26% variability. The large unexplained variance may be attributed to mechanics of neighboring structures (e.g., soleus or Achilles tendon mechanics) and proximal joint kinetics which may also contribute to ankle joint power and work performance, and were not taken into account. Further studies are encouraged to provide greater insight on the relationship between relative fascicle excursions and joint function.

  7. Relationship of medial gastrocnemius relative fascicle excursion and ankle joint power and work performance during gait in typically developing children

    PubMed Central

    Martín Lorenzo, Teresa; Albi Rodríguez, Gustavo; Rocon, Eduardo; Martínez Caballero, Ignacio; Lerma Lara, Sergio

    2017-01-01

    Abstract Muscle fascicles lengthen in response to chronic passive stretch through in-series sarcomere addition in order to maintain an optimum sarcomere length. In turn, the muscles’ force generating capacity, maximum excursion, and contraction velocity is enhanced. Thus, longer fascicles suggest a greater capacity to develop joint power and work. However, static fascicle length measurements may not be taking sarcomere length differences into account. Thus, we considered relative fascicle excursions through passive ankle dorsiflexion may better correlate with the capacity to generate joint power and work than fascicle length. Therefore, the aim of the present study was to determine if medial gastrocnemius relative fascicle excursions correlate with ankle joint power and work generation during gait in typically developing children. A sample of typically developing children (n = 10) were recruited for this study and data analysis was carried out on 20 legs. Medial gastrocnemius relative fascicle excursion from resting joint angle to maximum dorsiflexion was estimated from trigonometric relations of medial gastrocnemius pennation angle and thickness obtained from B-mode real-time ultrasonography. Furthermore, a three-dimensional motion capture system was used to obtain ankle joint work and power during the stance phase of gait. Significant correlations were found between relative fascicle excursion and peak power absorption (–) r(14) = −0.61, P = .012 accounting for 31% variability, positive work r(18) = 0.56, P = .021 accounting for 31% variability, and late stance positive work r(15) = 0.51, P = .037 accounting for 26% variability. The large unexplained variance may be attributed to mechanics of neighboring structures (e.g., soleus or Achilles tendon mechanics) and proximal joint kinetics which may also contribute to ankle joint power and work performance, and were not taken into account. Further studies are encouraged to provide greater insight on the relationship between relative fascicle excursions and joint function. PMID:28723790

  8. Edge Mechanisms for Power Excursion Control in Burning Plasmas

    NASA Astrophysics Data System (ADS)

    Hill, M. D.; Stacey, W. M.

    2017-10-01

    ITER must have active and preferably also passive control mechanisms that will limit inadvertent plasma power excursions which could trigger runaway fusion heating. We are identifying and investigating the potential of ion-orbit loss, impurity seeding, and various divertor ``choking'' phenomena to control or limit sudden increases in plasma density or temperature by reducing energy confinement, increasing radiation loss, etc., with the idea that such mechanisms could be tested on DIII-D and other existing tokamaks. We are assembling an edge-divertor code (GTEDGE-2) with a neutral transport model and a burn dynamics code, for this purpose. One potential control mechanism is the enhanced ion orbit loss from the thermalized ion distribution that would result from heating of the thermalized plasma ion distribution. Another possibility is impurity seeding with ions whose emissivity would increase sharply if the edge temperature increased. Enhanced radiative losses should also reduce the thermal energy flux across the separatrix, perhaps dropping the plasma into the poorer L-mode confinement regime. We will present some initial calculations to quantify these ideas. Work supported by US DOE under DE-FC02-04ER54698.

  9. A Review of Criticality Accidents 2000 Revision

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

    Thomas P. McLaughlin; Shean P. Monahan; Norman L. Pruvost

    Criticality accidents and the characteristics of prompt power excursions are discussed. Sixty accidental power excursions are reviewed. Sufficient detail is provided to enable the reader to understand the physical situation, the chemistry and material flow, and when available the administrative setting leading up to the time of the accident. Information on the power history, energy release, consequences, and causes are also included when available. For those accidents that occurred in process plants, two new sections have been included in this revision. The first is an analysis and summary of the physical and neutronic features of the chain reacting systems. Themore » second is a compilation of observations and lessons learned. Excursions associated with large power reactors are not included in this report.« less

  10. Testing the Self-Consistency of the Excursion Set Approach to Predicting the Dark Matter Halo Mass Function

    NASA Astrophysics Data System (ADS)

    Achitouv, I.; Rasera, Y.; Sheth, R. K.; Corasaniti, P. S.

    2013-12-01

    The excursion set approach provides a framework for predicting how the abundance of dark matter halos depends on the initial conditions. A key ingredient of this formalism is the specification of a critical overdensity threshold (barrier) which protohalos must exceed if they are to form virialized halos at a later time. However, to make its predictions, the excursion set approach explicitly averages over all positions in the initial field, rather than the special ones around which halos form, so it is not clear that the barrier has physical motivation or meaning. In this Letter we show that once the statistical assumptions which underlie the excursion set approach are considered a drifting diffusing barrier model does provide a good self-consistent description both of halo abundance as well as of the initial overdensities of the protohalo patches.

  11. Direction-specific impairment of stability limits and falls in children with developmental coordination disorder: Implications for rehabilitation.

    PubMed

    Fong, Shirley S M; Ng, Shamay S M; Chung, Louisa M Y; Ki, W Y; Chow, Lina P Y; Macfarlane, Duncan J

    2016-01-01

    Limit of stability (LOS) is an important yet under-examined postural control ability in children with developmental coordination disorder (DCD). This study aimed to (1) compare the LOS and fall frequencies of children with and without DCD, and (2) explore the relationships between LOS parameters and falls in the DCD population. Thirty primary school-aged children with DCD and twenty age- and sex-matched typically-developing children participated in the study. Postural control ability, specifically LOS in standing, was evaluated using the LOS test. Reaction time, movement velocity, maximum excursion, end point excursion, and directional control were then calculated. Self-reported fall incidents in the previous week were also documented. Multivariate analysis of variance results revealed that children with DCD had shorter LOS maximum excursion in the backward direction compared to the control group (p=0.003). This was associated with a higher number of falls in daily life (rho=-0.556, p=0.001). No significant between-groups differences were found in other LOS-derived outcomes (p>0.05). Children with DCD had direction-specific postural control impairment, specifically, diminished LOS in the backward direction. This is related to their falls in daily life. Therefore, improving LOS should be factored into rehabilitation treatment for children with DCD. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. TECHNICAL REVIEW OF ZPR-I ACCIDENTAL TRANSIENT--THE POWER EXCURSION, EXPOSURES, AND CLINICAL DATA

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

    Brittan, R. O.; Hasterlik, R. J.; Marinelli, L. D.

    1953-01-26

    On June 2. 1952. a large reactivity change was made manually in a ZPR-1 assembly causing a power excursion of about one kwh, which resulted in damage to the reactor core components and radiation exposure of some of the operating personnel to perhaps several hundred rep. A description is presented of the incident, estimates are made of the exposures, and early clinical data are summarized. (C.H.)

  13. Nonstationary envelope process and first excursion probability.

    NASA Technical Reports Server (NTRS)

    Yang, J.-N.

    1972-01-01

    The definition of stationary random envelope proposed by Cramer and Leadbetter, is extended to the envelope of nonstationary random process possessing evolutionary power spectral densities. The density function, the joint density function, the moment function, and the crossing rate of a level of the nonstationary envelope process are derived. Based on the envelope statistics, approximate solutions to the first excursion probability of nonstationary random processes are obtained. In particular, applications of the first excursion probability to the earthquake engineering problems are demonstrated in detail.

  14. Invariance in the recurrence of large returns and the validation of models of price dynamics

    NASA Astrophysics Data System (ADS)

    Chang, Lo-Bin; Geman, Stuart; Hsieh, Fushing; Hwang, Chii-Ruey

    2013-08-01

    Starting from a robust, nonparametric definition of large returns (“excursions”), we study the statistics of their occurrences, focusing on the recurrence process. The empirical waiting-time distribution between excursions is remarkably invariant to year, stock, and scale (return interval). This invariance is related to self-similarity of the marginal distributions of returns, but the excursion waiting-time distribution is a function of the entire return process and not just its univariate probabilities. Generalized autoregressive conditional heteroskedasticity (GARCH) models, market-time transformations based on volume or trades, and generalized (Lévy) random-walk models all fail to fit the statistical structure of excursions.

  15. Limits of Wave Runup and Corresponding Beach-Profile Change from Large-Scale Laboratory Data

    DTIC Science & Technology

    2010-01-01

    A nearly vertical scarp developed after 40 min of wave action, with the upper limit of beach change identified at the toe of the dune scarp. and...change UL was found to approximately equal the vertical excursion of total wave runup, Rtw. An exception was runs where beach or dune scarps were...approximately equal the vertical excursion of total wave runup, Rtw. An exception was runs where beach or dune scarps were produced, which substantially limit the

  16. Accurate Predictions of Mean Geomagnetic Dipole Excursion and Reversal Frequencies, Mean Paleomagnetic Field Intensity, and the Radius of Earth's Core Using McLeod's Rule

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.; Conrad, Joy

    1996-01-01

    The geomagnetic spatial power spectrum R(sub n)(r) is the mean square magnetic induction represented by degree n spherical harmonic coefficients of the internal scalar potential averaged over the geocentric sphere of radius r. McLeod's Rule for the magnetic field generated by Earth's core geodynamo says that the expected core surface power spectrum (R(sub nc)(c)) is inversely proportional to (2n + 1) for 1 less than n less than or equal to N(sub E). McLeod's Rule is verified by locating Earth's core with main field models of Magsat data; the estimated core radius of 3485 kn is close to the seismologic value for c of 3480 km. McLeod's Rule and similar forms are then calibrated with the model values of R(sub n) for 3 less than or = n less than or = 12. Extrapolation to the degree 1 dipole predicts the expectation value of Earth's dipole moment to be about 5.89 x 10(exp 22) Am(exp 2)rms (74.5% of the 1980 value) and the expected geomagnetic intensity to be about 35.6 (mu)T rms at Earth's surface. Archeo- and paleomagnetic field intensity data show these and related predictions to be reasonably accurate. The probability distribution chi(exp 2) with 2n+1 degrees of freedom is assigned to (2n + 1)R(sub nc)/(R(sub nc). Extending this to the dipole implies that an exceptionally weak absolute dipole moment (less than or = 20% of the 1980 value) will exist during 2.5% of geologic time. The mean duration for such major geomagnetic dipole power excursions, one quarter of which feature durable axial dipole reversal, is estimated from the modern dipole power time-scale and the statistical model of excursions. The resulting mean excursion duration of 2767 years forces us to predict an average of 9.04 excursions per million years, 2.26 axial dipole reversals per million years, and a mean reversal duration of 5533 years. Paleomagnetic data show these predictions to be quite accurate. McLeod's Rule led to accurate predictions of Earth's core radius, mean paleomagnetic field intensity, and mean geomagnetic dipole power excursion and axial dipole reversal frequencies. We conclude that McLeod's Rule helps unify geo-paleomagnetism, correctly relates theoretically predictable statistical properties of the core geodynamo to magnetic observation, and provides a priori information required for stochastic inversion of paleo-, archeo-, and/or historical geomagnetic measurements.

  17. High-resolution palaeomagnetic records of the Laschamp geomagnetic excursion from ODP Sites 1061 and 1062

    NASA Astrophysics Data System (ADS)

    Bourne, M. D.; Henderson, G. M.; Thomas, A. L.; Mac Niocaill, C.

    2012-12-01

    The Laschamp geomagnetic excursion (~41 ka) was a brief global deviation in geomagnetic field behaviour from that expected during normal secular variation. Previously published records suggest rapid changes in field direction and a concurrent substantial decrease in field intensity. We present here high-resolution palaeomagnetic records of the Laschamp excursion obtained from two Ocean Drilling Program (ODP) Sites 1061 and 1062 on the Blake-Bahama Outer Ridge (ODP Leg 172) and compare this record with previously published records of the Blake and Iceland Basin Excursions. Relatively high sedimentation rates (>10 cm kyr-1) at these locations allow the determination of transitional field behaviour during the excursion. Rather than assuming a constant sedimentation rate between assigned age tie-points, we employ measurements of 230Thxs concentration in the sediment to assess variations in the sedimentation rates through the core sections of interest. This allows us to better determine the temporal behaviour of the Laschamp excursion with greater accuracy and known uncertainty. The Laschamp excursion at this location appears to be much shorter in duration than the Blake and Iceland Basin excursions. Palaeomagnetic measurements of discrete samples from four cores reveal a single excursional feature, across an interval of 30 cm, associated with a broader palaeointensity low. The excursion is characterised by rapid transitions (less than 500 years) between a stable normal polarity and a partially-reversed, polarity. Peaks in inclination either side of the directional excursion indicate periods of time when the local field is dominated by vertical flux patches. Similar behaviour has been observed in records of the Iceland Basin Excursion from the same region. The palaeointensity record is in good agreement between the two sites. The palaeointensity record shows two minima, where the second dip in intensity is associated with a more limited directional deviation. Similar field intensity behaviour has been observed during the Blake excursion suggesting that the geomagnetic field stability may be reduced for relatively long durations, potentially up to tens of thousands of years.

  18. The Excursion Set Theory of Halo Mass Functions, Halo Clustering, and Halo Growth

    NASA Astrophysics Data System (ADS)

    Zentner, Andrew R.

    I review the excursion set theory with particular attention toward applications to cold dark matter halo formation and growth, halo abundance, and halo clustering. After a brief introduction to notation and conventions, I begin by recounting the heuristic argument leading to the mass function of bound objects given by Press and Schechter. I then review the more formal derivation of the Press-Schechter halo mass function that makes use of excursion sets of the density field. The excursion set formalism is powerful and can be applied to numerous other problems. I review the excursion set formalism for describing both halo clustering and bias and the properties of void regions. As one of the most enduring legacies of the excursion set approach and one of its most common applications, I spend considerable time reviewing the excursion set theory of halo growth. This section of the review culminates with the description of two Monte Carlo methods for generating ensembles of halo mass accretion histories. In the last section, I emphasize that the standard excursion set approach is the result of several simplifying assumptions. Dropping these assumptions can lead to more faithful predictions and open excursion set theory to new applications. One such assumption is that the height of the barriers that define collapsed objects is a constant function of scale. I illustrate the implementation of the excursion set approach for barriers of arbitrary shape. One such application is the now well-known improvement of the excursion set mass function derived from the "moving" barrier for ellipsoidal collapse. I also emphasize that the statement that halo accretion histories are independent of halo environment in the excursion set approach is not a general prediction of the theory. It is a simplifying assumption. I review the method for constructing correlated random walks of the density field in the more general case. I construct a simple toy model to illustrate that excursion set theory (with a constant barrier height) makes a simple and general prediction for the relation between halo accretion histories and the large-scale environments of halos: regions of high density preferentially contain late-forming halos and conversely for regions of low density. I conclude with a brief discussion of the importance of this prediction relative to recent numerical studies of the environmental dependence of halo properties.

  19. Effects of numerical dissipation and unphysical excursions on scalar-mixing estimates in large-eddy simulations

    NASA Astrophysics Data System (ADS)

    Sharan, Nek; Matheou, Georgios; Dimotakis, Paul

    2017-11-01

    Artificial numerical dissipation decreases dispersive oscillations and can play a key role in mitigating unphysical scalar excursions in large eddy simulations (LES). Its influence on scalar mixing can be assessed through the resolved-scale scalar, Z , its probability density function (PDF), variance, spectra, and the budget of the horizontally averaged equation for Z2. LES of incompressible temporally evolving shear flow enabled us to study the influence of numerical dissipation on unphysical scalar excursions and mixing estimates. Flows with different mixing behavior, with both marching and non-marching scalar PDFs, are studied. Scalar fields for each flow are compared for different grid resolutions and numerical scalar-convection term schemes. As expected, increasing numerical dissipation enhances scalar mixing in the development stage of shear flow characterized by organized large-scale pairings with a non-marching PDF, but has little influence in the self-similar stage of flows with marching PDFs. Flow parameters and regimes sensitive to numerical dissipation help identify approaches to mitigate unphysical excursions while minimizing dissipation.

  20. Reliability and feasibility of gait initiation centre-of-pressure excursions using a Wii® Balance Board in older adults at risk of falling.

    PubMed

    Lee, James; Webb, Graham; Shortland, Adam P; Edwards, Rebecca; Wilce, Charlotte; Jones, Gareth D

    2018-04-17

    Impairments in dynamic balance have a detrimental effect in older adults at risk of falls (OARF). Gait initiation (GI) is a challenging transitional movement. Centre of pressure (COP) excursions using force plates have been used to measure GI performance. The Nintendo Wii Balance Board (WBB) offers an alternative to a standard force plate for the measurement of CoP excursion. To determine the reliability of COP excursions using the WBB, and its feasibility within a 4-week strength and balance intervention (SBI) treating OARF. Ten OARF subjects attending SBI and ten young healthy adults, each performed three GI trials after 10 s of quiet stance from a standardised foot position (shoulder width) before walking forward 3 m to pick up an object. Averaged COP mediolateral (ML) and anteroposterior (AP) excursions (distance) and path-length time (GI-onset to first toe-off) were analysed. WBB ML (0.866) and AP COP excursion (0.895) reliability (ICC 3,1 ) was excellent, and COP path-length reliability was fair (0.517). Compared to OARF, healthy subjects presented with larger COP excursion in both directions and shorter COP path length. OARF subjects meaningfully improved their timed-up-and-go and ML COP excursion between weeks 1-4, while AP COP excursions, path length, and confidence-in-balance remained stable. COP path length and excursion directions probably measure different GI postural control attributes. Limitations in WBB accuracy and precision in transition tasks needs to be established before it can be used clinically to measure postural aspects of GI viably. The WBB could provide valuable clinical evaluation of balance function in OARF.

  1. Free-Piston Stirling Machine for Extreme Temperatures

    NASA Technical Reports Server (NTRS)

    Wood, James Gary (Inventor)

    2013-01-01

    A free piston Stirling machine including a thermal buffer tube extending from the machine's expansion space and surrounded by its heat rejector and its regenerator, a displacer cylinder extending from the thermal buffer tube to the compression space and surrounded by the heat rejecting heat exchanger, and a displacer that reciprocates within an excursion limit that extends into the regenerator by no more than 20% of the length of the regenerator during normal operation and preferably within excursion limits that are substantially the length of the heat rejector.

  2. A Power Source for Sunless Lunar Missions Using Lithium Combustion

    NASA Astrophysics Data System (ADS)

    Miller, T. F.; Paul, M. V.

    2016-11-01

    Some lunar exploration targets require non-solar power due to shading. Batteries provide very brief excursions into sunless areas. Undersea powerplants that burn metals have significantly higher specific energy than primary batteries and no exhaust.

  3. The effects of texting on driving performance in a driving simulator: the influence of driver age.

    PubMed

    Rumschlag, Gordon; Palumbo, Theresa; Martin, Amber; Head, Doreen; George, Rajiv; Commissaris, Randall L

    2015-01-01

    Distracted driving is a significant contributor to motor vehicle accidents and fatalities, and texting is a particularly significant form of driver distraction that continues to be on the rise. The present study examined the influence of driver age (18-59 years old) and other factors on the disruptive effects of texting on simulated driving behavior. While 'driving' the simulator, subjects were engaged in a series of brief text conversations with a member of the research team. The primary dependent variable was the occurrence of Lane Excursions (defined as any time the center of the vehicle moved outside the directed driving lane, e.g., into the lane for oncoming traffic or onto the shoulder of the road), measured as (1) the percent of subjects that exhibited Lane Excursions, (2) the number of Lane Excursions occurring and (3) the percent of the texting time in Lane Excursions. Multiple Regression analyses were used to assess the influence of several factors on driving performance while texting, including text task duration, texting skill level (subject-reported), texting history (#texts/week), driver gender and driver age. Lane Excursions were not observed in the absence of texting, but 66% of subjects overall exhibited Lane Excursions while texting. Multiple Regression analysis for all subjects (N=50) revealed that text task duration was significantly correlated with the number of Lane Excursions, and texting skill level and driver age were significantly correlated with the percent of subjects exhibiting Lane Excursions. Driver gender was not significantly correlated with Lane Excursions during texting. Multiple Regression analysis of only highly skilled texters (N=27) revealed that driver age was significantly correlated with the number of Lane Excursions, the percent of subjects exhibiting Lane Excursions and the percent of texting time in Lane Excursions. In contrast, Multiple Regression analysis of those drivers who self-identified as not highly skilled texters (N=23) revealed that text task duration was significantly correlated with the number of Lane Excursions. The present studies confirm past reports that texting impairs driving simulator performance. Moreover, the present study demonstrates that for highly skilled texters, the effects of texting on driving are actually worse for older drivers. Given the increasing frequency of texting while driving within virtually all age groups, these data suggest that 'no texting while driving' education and public service messages need to be continued, and they should be expanded to target older drivers as well. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Excursions out-of-lane versus standard deviation of lateral position as outcome measure of the on-the-road driving test.

    PubMed

    Verster, Joris C; Roth, Thomas

    2014-07-01

    The traditional outcome measure of the Dutch on-the-road driving test is the standard deviation of lateral position (SDLP), the weaving of the car. This paper explores whether excursions out-of-lane are a suitable additional outcome measure to index driving impairment. A literature search was conducted to search for driving tests that used both SDLP and excursions out-of-lane as outcome measures. The analyses were limited to studies examining hypnotic drugs because several of these drugs have been shown to produce next-morning sedation. Standard deviation of lateral position was more sensitive in demonstrating driving impairment. In fact, solely relying on excursions out-of-lane as outcome measure incorrectly classifies approximately half of impaired drives as unimpaired. The frequency of excursions out-of-lane is determined by the mean lateral position within the right traffic lane. Defining driving impairment as having a ΔSDLP > 2.4 cm, half of the impaired driving tests (51.2%, 43/84) failed to produce excursions out-of-lane. Alternatively, 20.9% of driving tests with ΔSDLP < 2.4 cm (27/129) had at least one excursion out-of-lane. Excursions out-of-lane are neither a suitable measure to demonstrate driving impairment nor is this measure sufficiently sensitive to differentiate adequately between differences in magnitude of driving impairment. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Potential Cislunar and Interplanetary Proving Ground Excursion Trajectory Concepts

    NASA Technical Reports Server (NTRS)

    McGuire, Melissa L.; Strange, Nathan J.; Burke, Laura M.; MacDonald, Mark A.; McElrath, Timothy P.; Landau, Damon F.; Lantoine, Gregory; Hack, Kurt J.; Lopez, Pedro

    2016-01-01

    NASA has been investigating potential translunar excursion concepts to take place in the 2020s that would be used to test and demonstrate long duration life support and other systems needed for eventual Mars missions in the 2030s. These potential trajectory concepts could be conducted in the proving ground, a region of cislunar and near-Earth interplanetary space where international space agencies could cooperate to develop the technologies needed for interplanetary spaceflight. Enabled by high power Solar Electric Propulsion (SEP) technologies, the excursion trajectory concepts studied are grouped into three classes of increasing distance from the Earth and increasing technical difficulty: the first class of excursion trajectory concepts would represent a 90-120 day round trip trajectory with abort to Earth options throughout the entire length, the second class would be a 180-210 day round trip trajectory with periods in which aborts would not be available, and the third would be a 300-400 day round trip trajectory without aborts for most of the length of the trip. This paper provides a top-level summary of the trajectory and mission design of representative example missions of these three classes of excursion trajectory concepts.

  6. High-resolution palaeomagnetic records of the Laschamp geomagnetic excursion from the Blake Ridge

    NASA Astrophysics Data System (ADS)

    Mac Niocaill, C.; Bourne, M. D.; Thomas, A. L.; Henderson, G. M.

    2013-05-01

    Geomagnetic excursions are brief (1000s of years) deviations in geomagnetic field behaviour from that expected during 'normal secular' variation. The Laschamp excursion (~41 ka) was a global deviation in geomagnetic field behaviour. Previously published records suggest rapid changes in field direction and a concurrent substantial decrease in field intensity. Accurate dating of excursions and determinations of their durations from multiple locations is vital to our understanding to global field behaviour during these deviations. We present here high-resolution palaeomagnetic records of the Laschamp excursion obtained from two Ocean Drilling Program (ODP) Sites 1061 and 1062 on the Blake-Bahama Outer Ridge (ODP Leg 172) Relatively high sedimentation rates (~30-40 cm kyr-1) at these locations allow the determination of transitional field behaviour during the excursion. Despite their advantages, sedimentary records can be limited by the potential for unrecognized variations in sedimentation rates between widely spaced age-constrained boundaries. Rather than assuming a constant sedimentation rate between assigned age tie-points, we employ measurements of the concentration of 230Thxs in the sediment. 230Thxs is a constant flux proxy and may be used to assess variations in the sedimentation rates through the core sections of interest. Following this approach, we present a new age model for Site 1061 that allows us to better determine the temporal behaviour of the Laschamp excursion with greater accuracy and known uncertainty. Palaeomagnetic measurements of discrete samples from four cores reveal a single excursional feature, across an interval of 30 cm, associated with a broader palaeointensity low. The excursion is characterised by rapid transitions (less than 200 years) between a stable normal polarity and a partially-reversed, polarity. Peaks in inclination either side of the directional excursion indicate periods of time when the local field is dominated by vertical flux patches. Similar behaviour has been observed in records of the Iceland Basin Excursion from the same region. The palaeointensity record is in good agreement between the two sites. The palaeointensity record shows two prominent minima, the first associated with the Laschamp excursion at 41 ka and the second at ~34 ka, possibly associated with the elusive 'Mono-Lake' excursion. Similar field intensity behaviour has been observed during the Blake excursion suggesting that the geomagnetic field stability may be reduced for relatively long durations, potentially up to tens of thousands of years. Using the 230Thxs derived sedimentation rate, we determine that the directional excursion at this location was no longer than ~400 years, occurring within a palaeointensity low lasting 2000 years. We compare this record with previously published records of the Blake and Iceland Basin Excursions from nearby locations. The Laschamp excursion at this location appears to be much shorter in duration than the Blake and Iceland Basin excursions.

  7. Exploring the Angstrom Excursion of Au Nanoparticles Excited away from a Metal Surface by an Impulsive Acoustic Perturbation.

    PubMed

    Kim, Ji-Wan; Kovalenko, Oleksandr; Liu, Yu; Bigot, Jean-Yves

    2016-12-27

    We report the anharmonic angstrom dynamics of self-assembled Au nanoparticles (Au:NPs) away from a nickel surface on top of which they are coupled by their near-field interaction. The deformation and the oscillatory excursion away from the surface are induced by picosecond acoustic pulses and probed at the surface plasmon resonance with femtosecond laser pulses. The overall dynamics are due to an efficient transfer of translational momentum from the Ni surface to the Au:NPs, therefore avoiding usual thermal effects and energy redistribution among the electronic states. Two modes are clearly revealed by the oscillatory shift of the Au:NPs surface plasmon resonance-the quadrupole deformation mode due to the transient ellipsoid shape and the excursion mode when the Au:NPs bounce away from the surface. We find that, contrary to the quadrupole mode, the excursion mode is sensitive to the distance between Au:NPs and Ni. Importantly, the excursion dynamics display a nonsinusoidal motion that cannot be explained by a standard harmonic potential model. A detailed modeling of the dynamics using a Hamaker-type Lennard-Jones potential between two media is performed, showing that each Au:NPs coherently evolves in a nearly one-dimensional anharmonic potential with a total excursion of ∼1 Å. This excursion induces a shift of the surface plasmon resonance detectable because of the strong near-field interaction. This general method of observing the spatiotemporal dynamics with angstrom and picosecond resolutions can be directly transposed to many nanostructures or biosystems to reveal the interaction and contact mechanism with their surrounding medium while remaining in their fundamental electronic states.

  8. ISRU Reactant, Fuel Cell Based Power Plant for Robotic and Human Mobile Exploration Applications

    NASA Technical Reports Server (NTRS)

    Baird, Russell S.; Sanders, Gerald; Simon, Thomas; McCurdy, Kerri

    2003-01-01

    Three basic power generation system concepts are generally considered for lander, rover, and Extra-Vehicular Activity (EVA) assistant applications for robotic and human Moon and Mars exploration missions. The most common power system considered is the solar array and battery system. While relatively simple and successful, solar array/battery systems have some serious limitations for mobile applications. For typical rover applications, these limitations include relatively low total energy storage capabilities, daylight only operating times (6 to 8 hours on Mars), relatively short operating lives depending on the operating environment, and rover/lander size and surface use constraints. Radioisotope power systems are being reconsidered for long-range science missions. Unfortunately, the high cost, political controversy, and launch difficulties that are associated with nuclear-based power systems suggests that the use of radioisotope powered landers, rovers, and EVA assistants will be limited. The third power system concept now being considered are fuel cell based systems. Fuel cell power systems overcome many of the performance and surface exploration limitations of solar array/battery power systems and the prohibitive cost and other difficulties associated with nuclear power systems for mobile applications. In an effort to better understand the capabilities and limitations of fuel cell power systems for Moon and Mars exploration applications, NASA is investigating the use of in-Situ Resource Utilization (ISRU) produced reactant, fuel cell based power plants to power robotic outpost rovers, science equipment, and future human spacecraft, surface-excursion rovers, and EVA assistant rovers. This paper will briefly compare the capabilities and limitations of fuel cell power systems relative to solar array/battery and nuclear systems, discuss the unique and enhanced missions that fuel cell power systems enable, and discuss the common technology and system attributes possible for robotic and human exploration to maximize scientific return and minimize cost and risk to both. Progress made to date at the Johnson Space Center on an ISRU producible reactant, Proton Exchange Membrane (PEM) fuel cell based power plant project to demonstrate the concept in conjunction with rover applications will be presented in detail.

  9. ISRU Reactant, Fuel Cell Based Power Plant for Robotic and Human Mobile Exploration Applications

    NASA Astrophysics Data System (ADS)

    Baird, Russell S.; Sanders, Gerald; Simon, Thomas; McCurdy, Kerri

    2003-01-01

    Three basic power generation system concepts are generally considered for lander, rover, and Extra-Vehicular Activity (EVA) assistant applications for robotic and human Moon and Mars exploration missions. The most common power system considered is the solar array and battery system. While relatively simple and successful, solar array/battery systems have some serious limitations for mobile applications. For typical rover applications, these limitations include relatively low total energy storage capabilities, daylight only operating times (6 to 8 hours on Mars), relatively short operating lives depending on the operating environment, and rover/lander size and surface use constraints. Radioisotope power systems are being reconsidered for long-range science missions. Unfortunately, the high cost, political controversy, and launch difficulties that are associated with nuclear-based power systems suggests that the use of radioisotope powered landers, rovers, and EVA assistants will be limited. The third power system concept now being considered are fuel cell based systems. Fuel cell power systems overcome many of the performance and surface exploration limitations of solar array/battery power systems and the prohibitive cost and other difficulties associated with nuclear power systems for mobile applications. In an effort to better understand the capabilities and limitations of fuel cell power systems for Moon and Mars exploration applications. NASA is investigating the use of In-Situ Resource Utilization (ISRU) produced reactant, fuel cell based power plants to power robotic outpost rovers, science equipment, and future human spacecraft, surface-excursion rovers, and EVA assistant rovers. This paper will briefly compare the capabilities and limitations of fuel cell power systems relative to solar array/battery and nuclear systems, discuss the unique and enhanced missions that fuel cell power systems enable, and discuss the common technology and system attributes possible for robotic and human exploration to maximize scientific return and minimize cost and risk to both. Progress made to date at the Johnson Space Center on an ISRU producible reactant. Proton Exchange Membrane (PEM) fuel cell based power plant project for use in the first demonstration of this concept in conjunction with rover applications will be presented in detail.

  10. A Comparison of two Brunhes Chron Geomagnetic Excursions Recorded by Neighbouring North Atlantic Sites (ODP Sites 1062 and 1063)

    NASA Astrophysics Data System (ADS)

    Bourne, M.; Mac Niocaill, C.; Knudsen, M. F.; Thomas, A. L.; Henderson, G. M.

    2012-04-01

    A full picture of geomagnetic field behaviour during the Blake excursion is currently limited by a paucity of robust, high-resolution records of this ambiguous event. Some records seem to point towards a 'double-excursion' character whilst others fail to record the Blake excursion at all. We present here a high-resolution record of the Blake excursion obtained from Ocean Drilling Program (ODP) Site 1062 on the Blake Outer Ridge (ODP Leg 172). Palaeomagnetic measurements in three cores reveal a single excursional feature associated with a broad palaeointensity low, characterised by rapid transitions (less than 500 years) between a stable normal polarity and a fully-reversed, pseudo-stable polarity. A relatively high sedimentation rate (~10 cm kyr-1) allows the determination of transitional field behaviour during the excursion. Rather than assuming a constant sedimentation rate between assigned age tie-points, we employ measurements of 230Thxs concentrations in the sediment to assess variations in the sedimentation rates through the core sections of interest. This allows us to determine an age and duration for the two excursions with greater accuracy and known uncertainty. Our new age model gives an age of 127 ka for the midpoint of the Blake event at Site 1062. The age model also gives a duration for the directional excursion of 7.1±1.6 kyr. This duration is similar to that previously reported for the Iceland Basin Excursion (~185 ka) from the nearby Bermuda Rise (ODP Site 1063), which recorded a ~7-8 kyr event. Similarly, a high sedimentation rate (10-15 cm kyr-1) at this site allows a high-resolution reconstruction of the geomagnetic field behaviour during the Iceland Basin Excursion. The Site 1063 palaeomagnetic record suggests more complicated behaviour than that of the Blake excursion at Site 1062. Instead, transitional VGP paths are characterised by stop-and-go behaviour between VGP clusters that may be related to long-standing thermo-dynamic features of the core-mantle system. The long duration of fully reversed directions at the two sites is somewhat longer than that typically assumed for excursions and appears to suggest that there may be a degree of stability associated with the two excursional events. We will present a comparison of the geomagnetic field behaviour of the two excursions as recorded at these two sites.

  11. SPERT I DESTRUCTIVE TEST PROGRAM SAFETY ANALYSIS REPORT

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

    Spano, A.H.; Miller, R.W.

    1962-06-15

    The water-moderated core used for destructive experiments is mounted in the Spent I open-type reactor vessel, which has no provision for pressurization or forced coolant flow. The core is an array of highly enriched aluminum clad, plate-type fuel assemblies, using four bladetype, gang-operated control rods. Reactor transients are initiated at ambient temperature by step-insentions of reactivity, using a control rod which can be quickly ejected from the core. Following an initial series of static measurements to determine the basic- reactor properties of the test core, a series of nondestructive, self-limiting power excursion tests was performed, which covered a reactor periodmore » range down to the point where minor fuel plate damage first occurred -approximately for a 10- msec period test. These tests provided power, temperature, and pressure data. Additional kinetic teste in the period region between 10 and 5 msec were completed to explore the region of limited core damage. Fuel plate damage results included plate distortion, cladding cracking, and fuel melting. These exploratory tests were valuable in revealing unexpected changes in the dependence of pressure, temperature, burst energy, and burst shape parameters on reactor period, although the dependence of peak power on reactor period was not significantly changed. An evaluation of hazards involved in conducting the 2- msec test, based on pessimistic assumptions regarding fission product release and weather conditions, indicates that with the procedural controls normally exercised in the conduct of any transient test at Spent and the special controls to be in effect during the destructive test series, no significant hazard to personnel or to the general public will be obtained. All nuclear operation is conducted remotely approximately 1/2 mile from the reactor building. Discussion is also given of the supervision and control of personnel during and after each destructive test, and of the plans for re-entry, cleanup, and restoration of the facility. (auth)« less

  12. Gravitational dynamos and the low-frequency geomagnetic secular variation.

    PubMed

    Olson, P

    2007-12-18

    Self-sustaining numerical dynamos are used to infer the sources of low-frequency secular variation of the geomagnetic field. Gravitational dynamo models powered by compositional convection in an electrically conducting, rotating fluid shell exhibit several regimes of magnetic field behavior with an increasing Rayleigh number of the convection, including nearly steady dipoles, chaotic nonreversing dipoles, and chaotic reversing dipoles. The time average dipole strength and dipolarity of the magnetic field decrease, whereas the dipole variability, average dipole tilt angle, and frequency of polarity reversals increase with Rayleigh number. Chaotic gravitational dynamos have large-amplitude dipole secular variation with maximum power at frequencies corresponding to a few cycles per million years on Earth. Their external magnetic field structure, dipole statistics, low-frequency power spectra, and polarity reversal frequency are comparable to the geomagnetic field. The magnetic variability is driven by the Lorentz force and is characterized by an inverse correlation between dynamo magnetic and kinetic energy fluctuations. A constant energy dissipation theory accounts for this inverse energy correlation, which is shown to produce conditions favorable for dipole drift, polarity reversals, and excursions.

  13. Gravitational dynamos and the low-frequency geomagnetic secular variation

    PubMed Central

    Olson, P.

    2007-01-01

    Self-sustaining numerical dynamos are used to infer the sources of low-frequency secular variation of the geomagnetic field. Gravitational dynamo models powered by compositional convection in an electrically conducting, rotating fluid shell exhibit several regimes of magnetic field behavior with an increasing Rayleigh number of the convection, including nearly steady dipoles, chaotic nonreversing dipoles, and chaotic reversing dipoles. The time average dipole strength and dipolarity of the magnetic field decrease, whereas the dipole variability, average dipole tilt angle, and frequency of polarity reversals increase with Rayleigh number. Chaotic gravitational dynamos have large-amplitude dipole secular variation with maximum power at frequencies corresponding to a few cycles per million years on Earth. Their external magnetic field structure, dipole statistics, low-frequency power spectra, and polarity reversal frequency are comparable to the geomagnetic field. The magnetic variability is driven by the Lorentz force and is characterized by an inverse correlation between dynamo magnetic and kinetic energy fluctuations. A constant energy dissipation theory accounts for this inverse energy correlation, which is shown to produce conditions favorable for dipole drift, polarity reversals, and excursions. PMID:18048345

  14. Downflow dryout in a heated ribbed vertical annulus with a cosine power profile (Results from test series ECS-2, WSR, and ECS-2cE)

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

    Larson, T.K.; Anderson, J.L.; Condie, K.G.

    Experiments designed to investigate surface dryout in a heated, ribbed annulus test section simulating one of the annular coolant channels of a Savannah River Plant production reactor Mark 22 fuel assembly have been conducted at the Idaho National Engineering Laboratory. The inner surface of the annulus was constructed of aluminum and was electrically heated to provide an axial cosine power profile and a flat azimuthal power shape. Data presented in this report are from the ECS-2, WSR, and ECS-2cE series of tests. These experiments were conducted to examine the onset of wall thermal excursion for a range of flow, inletmore » fluid temperature, and annulus outlet pressure. Hydraulic boundary conditions on the test section represent flowrates (0.1--1.4 1/s), inlet fluid temperatures (293--345 K), and outlet pressures (-18--139.7 cm of water relative to the bottom of the heated length (61--200 cm of water relative to the bottom of the lower plenum)) expected to occur during the Emergency Coolant System (ECS) phase of postulated Loss-of-Coolant Accident in a production reactor. The onset of thermal excursion based on the present data is consistent with data gathered in test rigs with flat axial power profiles. The data indicate that wall dryout is primarily a function of liquid superficial velocity. Air entrainment rate was observed to be a strong function of the boundary conditions (primarily flowrate and liquid temperature), but had a minor effect on the power at the onset of thermal excursion for the range of conditions examined. 14 refs., 33 figs., 13 tabs.« less

  15. Advanced Plasma Propulsion for Human Missions to Jupiter

    NASA Technical Reports Server (NTRS)

    Donahue, Benjamin B.; Pearson, J. Boise

    1999-01-01

    This paper will briefly identify a promising fusion plasma power source, which when coupled with a promising electric thruster technology would provide for an efficient interplanetary transfer craft suitable to a 4 year round trip mission to the Jovian system. An advanced, nearly radiation free Inertial Electrostatic Confinement scheme for containing fusion plasma was judged as offering potential for delivering the performance and operational benefits needed for such high energy human expedition missions, without requiring heavy superconducting magnets for containment of the fusion plasma. Once the Jovian transfer stage has matched the heliocentric velocity of Jupiter, the energy requirements for excursions to its outer satellites (Callisto, Ganymede and Europa) by smaller excursion craft are not prohibitive. The overall propulsion, power and thruster system is briefly described and a preliminary vehicle mass statement is presented.

  16. 30 CFR 56.5001 - Exposure limits for airborne contaminants.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... concentration shall be determined by phase contrast microscopy (PCM) using the OSHA Reference Method in OSHA's.../cc excursion limit, samples shall be further analyzed using transmission electron microscopy...

  17. 30 CFR 56.5001 - Exposure limits for airborne contaminants.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... concentration shall be determined by phase contrast microscopy (PCM) using the OSHA Reference Method in OSHA's.../cc excursion limit, samples shall be further analyzed using transmission electron microscopy...

  18. 30 CFR 56.5001 - Exposure limits for airborne contaminants.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... concentration shall be determined by phase contrast microscopy (PCM) using the OSHA Reference Method in OSHA's.../cc excursion limit, samples shall be further analyzed using transmission electron microscopy...

  19. 30 CFR 56.5001 - Exposure limits for airborne contaminants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... concentration shall be determined by phase contrast microscopy (PCM) using the OSHA Reference Method in OSHA's.../cc excursion limit, samples shall be further analyzed using transmission electron microscopy...

  20. Monolithic integration of fine cylindrical glass microcapillaries on silicon for electrophoretic separation of biomolecules

    PubMed Central

    Cao, Zhen; Ren, Kangning; Wu, Hongkai; Yobas, Levent

    2012-01-01

    We demonstrate monolithic integration of fine cylindrical glass microcapillaries (diameter ∼1 μm) on silicon and evaluate their performance for electrophoretic separation of biomolecules. Such microcapillaries are achieved through thermal reflow of a glass layer on microstructured silicon whereby slender voids are moulded into cylindrical tubes. The process allows self-enclosed microcapillaries with a uniform profile. A simplified method is also described to integrate the microcapillaries with a sample-injection cross without the requirement of glass etching. The 10-mm-long microcapillaries sustain field intensities up to 90 kV/m and limit the temperature excursions due to Joule heating to a few degrees Celsius only. PMID:23874369

  1. Epaxial muscle fiber architecture favors enhanced excursion and power in the leaper Galago senegalensis

    PubMed Central

    Huq, Emranul; Wall, Christine E; Taylor, Andrea B

    2015-01-01

    Galago senegalensis is a habitual arboreal leaper that engages in rapid spinal extension during push-off. Large muscle excursions and high contraction velocities are important components of leaping, and experimental studies indicate that during leaping by G. senegalensis, peak power is facilitated by elastic storage of energy. To date, however, little is known about the functional relationship between epaxial muscle fiber architecture and locomotion in leaping primates. Here, fiber architecture of select epaxial muscles is compared between G. senegalensis (n = 4) and the slow arboreal quadruped, Nycticebus coucang (n = 4). The hypothesis is tested that G. senegalensis exhibits architectural features of the epaxial muscles that facilitate rapid and powerful spinal extension during the take-off phase of leaping. As predicted, G. senegalensis epaxial muscles have relatively longer, less pinnate fibers and higher ratios of tendon length-to-fiber length, indicating the capacity for generating relatively larger muscle excursions, higher whole-muscle contraction velocities, and a greater capacity for elastic energy storage. Thus, the relatively longer fibers and higher tendon length-to-fiber length ratios can be functionally linked to leaping performance in G. senegalensis. It is further predicted that G. senegalensis epaxial muscles have relatively smaller physiological cross-sectional areas (PCSAs) as a consequence of an architectural trade-off between fiber length (excursion) and PCSA (force). Contrary to this prediction, there are no species differences in relative PCSAs, but the smaller-bodied G. senegalensis trends towards relatively larger epaxial muscle mass. These findings suggest that relative increase in muscle mass in G. senegalensis is largely attributable to longer fibers. The relative increase in erector spinae muscle mass may facilitate sagittal flexibility during leaping. The similarity between species in relative PCSAs provides empirical support for previous work linking osteological features of the vertebral column in lorisids with axial stability and reduced muscular effort associated with slow, deliberate movements during anti-pronograde locomotion. PMID:26184388

  2. Evaluation of a new paleosecular variation activity index as a diagnostic tool for geomagnetic field variations

    NASA Astrophysics Data System (ADS)

    Panovska, Sanja; Constable, Catherine

    2015-04-01

    Geomagnetic indices like Dst, K and A, have been used since the early twentieth century to characterize activity in the external part of the modern geomagnetic field and as a diagnostic for space weather. These indices reflect regional and global activity and serve as a proxy for associated physical processes. However, no such tools are yet available for the internal geomagnetic field driven by the geodynamo in Earth's liquid outer core. To some extent this reflects limited spatial and temporal sampling for longer timescales associated with paleomagnetic secular variation, but recent efforts in both paleomagnetic data gathering and modeling activity suggest that longer term characterization of the internal geomagnetic weather/climate and its variability would be useful. Specifically, we propose an index for activity in paleosecular variation, useful as both a local and global measure of field stability during so-called normal secular variation and as a means of identifying more extreme behavior associated with geomagnetic excursions and reversals. To date, geomagnetic excursions have been identified by virtual geomagnetic poles (VGPs) deviating more than some conventional limit from the geographic pole (often 45 degrees), and/or by periods of significant intensity drops below some critical value, for example 50% of the present-day field. We seek to establish a quantitative definition of excursions in paleomagnetic records by searching for synchronous directional deviations and lows in relative paleointensity. We combine paleointensity variations with deviations from the expected geocentric axial dipole (GAD) inclination in a single parameter, which we call the paleosecular variation (PSV) activity index. This new diagnostic can be used on any geomagnetic time series (individual data records, model predictions, spherical harmonic coefficients, etc.) to characterize the level of paleosecular variation activity, find excursions, or even study incipient reversals. Currently reversals can only be detected after they have occurred. A baseline for the new index is established using modern and Holocene geomagnetic field data and models to analyze 'normal' variability. We extend our analyses to the 100 ka interval where several excursions have been identified. We discuss the diminished or absent signatures of excursions in some records, the apparent transgressive behavior of detected excursions, and implications for transitional field behavior. The absence of specific excursions in some sediment records is attributed to smoothing by the sedimentary remanence acquisition process and low sedimentation rates. Overall PSV activity index is inversely correlated with dipole moment, indicating stronger impacts of non-axial-dipole secular variations during periods of low axial dipole strength. Excursional events found with the PSV activity index are analyzed in the context of global probability density functions for VGP positions. We studied the appearance of VGP clusters of the excursions to find the common characteristics of these instabilities, including the non-axial dipole features of the geomagnetic field. A better understanding of geomagnetic excursions will aid attempts to predict when such events might occur in the future.

  3. Terahertz generation via laser coupling to anharmonic carbon nanotube array

    NASA Astrophysics Data System (ADS)

    Sharma, Soni; Vijay, A.

    2018-02-01

    A scheme of terahertz radiation generation employing a matrix of anharmonic carbon nanotubes (CNTs) embedded in silica is proposed. The matrix is irradiated by two collinear laser beams that induce large excursions on CNT electrons and exert a nonlinear force at the beat frequency ω = ω1-ω2. The force derives a nonlinear current producing THz radiation. The THz field is resonantly enhanced at the plasmon resource, ω = ω p ( 1 + β ) / √{ 2 } , where ωp is the plasma frequency and β is a characteristic parameter. Collisions are a limiting factor, suppressing the plasmon resonance. For typical values of plasma parameters, we obtain power conversion efficiency of the order of 10-6.

  4. Solar maximum mission panel jettison analysis remote manipulator system

    NASA Technical Reports Server (NTRS)

    Bauer, R. B.

    1980-01-01

    A study is presented of the development of the Remote Manipulator System (RMS) configurations for jettison of the solar panels on the Solar Maximum Mission/Multimission Satellite. A valid RMS maneuver between jettison configurations was developed. Arm and longeron loads and effector excursions due to the solar panel jettison were determined to see if they were within acceptable limits. These loads and end effector excursions were analyzed under two RMS modes, servos active in position hold submode, and in the brakes on mode.

  5. Relationships Between Varus–Valgus Laxity of the Severely Osteoarthritic Knee and Gait, Instability, Clinical Performance, and Function

    PubMed Central

    Freisinger, Gregory M.; Hutter, Erin E.; Lewis, Jacqueline; Granger, Jeffrey F.; Glassman, Andrew H.; Beal, Matthew D.; Pan, Xueliang; Schmitt, Laura C.; Siston, Robert A.; Chaudhari, Ajit M.W.

    2017-01-01

    Increased varus–valgus laxity has been reported in individuals with knee osteoarthritis (OA) compared to controls. However, the majority of previous investigations may not report truly passive joint laxity, as their tests have been performed on conscious participants who could be guarding against motion with muscle contraction during laxity evaluation. The purpose of this study was to investigate how a measure of passive knee laxity, recorded when the participant is under anesthesia, is related to varus–valgus excursion during gait, clinical measures of performance, perceived instability, and self-reported function in participants with severe knee OA. We assessed passive varus–valgus knee laxity in 29 participants (30 knees) with severe OA, as they underwent total knee arthroplasty (TKA). Participants also completed gait analysis, clinical assessment of performance (6-min walk (6 MW), stair climbing test (SCT), isometric knee strength), and self-reported measures of function (perceived instability, Knee injury, and Osteoarthritis Outcome Score (KOOS) a median of 18 days before the TKA procedure. We observed that greater passive varus–valgus laxity was associated with greater varus–valgus excursion during gait (R2 =0.34, p =0.002). Significant associations were also observed between greater laxity and greater isometric knee extension strength (p =0.014), farther 6 MW distance (p =0.033) and shorter SCT time (p =0.046). No relationship was observed between passive varus–valgus laxity and isometric knee flexion strength, perceived instability, or any KOOS subscale. The conflicting associations between laxity, frontal excursion during gait, and functional performance suggest a complex relationship between laxity and knee cartilage health, clinical performance, and self-reported function that merits further study. PMID:27664972

  6. "To See How Far I Can Go": Benefits of "Fun" in Encouraging Civic Engagement and Building Self-Efficacy among New York Community College Students

    ERIC Educational Resources Information Center

    Naish, Paul D.

    2015-01-01

    Community Days, an innovative initiative to foster community service and civic engagement at the City University of New York's new Guttman Community College, encourages students to perform volunteer work around the city. What makes the program unique are opportunities for students to take self-directed excursions and enjoy free resources in the…

  7. Glucose and triglyceride excursions following a standardized meal in individuals with diabetes: ELSA-Brasil study.

    PubMed

    Riboldi, Bárbara P; Luft, Vivian C; de Castilhos, Cristina D; de Cardoso, Letícia O; Schmidt, Maria I; Barreto, Sandhi M; de Sander, Maria F; Alvim, Sheila M; Duncan, Bruce B

    2015-02-13

    To assess glucose and triglyceride excursions 2 hours after the ingestion of a standardized meal and their associations with clinical characteristics and cardiovascular complications in individuals with diabetes. Blood samples of 898 subjects with diabetes were collected at fasting and 2 hours after a meal containing 455 kcal, 14 g of saturated fat and 47 g of carbohydrates. Self-reported morbidity, socio-demographic characteristics and clinical measures were obtained by interview and exams performed at the baseline visit of the ELSA-Brasil cohort study. Median (interquartile range, IQR) for fasting glucose was 150.5 (123-198) mg/dL and for fasting triglycerides 140 (103-199) mg/dL. The median excursion for glucose was 45 (15-76) mg/dL and for triglycerides 26 (11-45) mg/dL. In multiple linear regression, a greater glucose excursion was associated with higher glycated hemoglobin (10.7, 95% CI 9.1-12.3 mg/dL), duration of diabetes (4.5; 2.6-6.4 mg/dL, per 5 year increase), insulin use (44.4; 31.7-57.1 mg/dL), and age (6.1; 2.5-9.6 mg/dL, per 10 year increase); and with lower body mass index (-5.6; -8.4- -2.8 mg/dL, per 5 kg/m2 increase). In adjusted logistic regression models, a greater glucose excursion was marginally associated with the presence of cardiovascular comorbidities (coronary heart disease, myocardial infarction and angina) in those with obesity. A greater postprandial glycemic response to a small meal was positively associated with indicators of a decreased capacity for insulin secretion and negatively associated with obesity. No pattern of response was observed with a greater postprandial triglyceride excursion.

  8. THE EFFECTS OF TRANSIENTS ON PHOTOSPHERIC AND CHROMOSPHERIC POWER DISTRIBUTIONS

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

    Samanta, T.; Banerjee, D.; Pant, V.

    2016-09-01

    We have observed a quiet-Sun region with the Swedish 1 m Solar Telescope equipped with the CRISP Imaging SpectroPolarimeter. High-resolution, high-cadence, H α line scanning images were taken to observe different layers of the solar atmosphere from the photosphere to upper chromosphere. We study the distribution of power in different period bands at different heights. Power maps of the upper photosphere and the lower chromosphere show suppressed power surrounding the magnetic-network elements, known as “magnetic shadows.” These also show enhanced power close to the photosphere, traditionally referred to as “power halos.” The interaction between acoustic waves and inclined magnetic fieldsmore » is generally believed to be responsible for these two effects. In this study we explore whether small-scale transients can influence the distribution of power at different heights. We show that the presence of transients, like mottles, Rapid Blueshifted Excursions (RBEs), and Rapid Redshifted Excursions (RREs), can strongly influence the power maps. The short and finite lifetime of these events strongly affects all power maps, potentially influencing the observed power distribution. We show that Doppler-shifted transients like RBEs and RREs that occur ubiquitously can have a dominant effect on the formation of the power halos in the quiet Sun. For magnetic shadows, transients like mottles do not seem to have a significant effect on the power suppression around 3 minutes, and wave interaction may play a key role here. Our high-cadence observations reveal that flows, waves, and shocks manifest in the presence of magnetic fields to form a nonlinear magnetohydrodynamic system.« less

  9. Effects of 50 mg vildagliptin twice daily vs. 50 mg sitagliptin once daily on blood glucose fluctuations evaluated by long-term self-monitoring of blood glucose.

    PubMed

    Nomoto, Hiroshi; Kimachi, Kimihiko; Miyoshi, Hideaki; Kameda, Hiraku; Cho, Kyu Yong; Nakamura, Akinobu; Nagai, So; Kondo, Takuma; Atsumi, Tatsuya

    2017-04-29

    To date, several clinical trials have compared differences in glucose fluctuation observed with dipeptidyl peptidase-4 inhibitor treatment in patients with type 2 diabetes mellitus. However, most patients were assessed for limited periods or during hospitalization. The aim of the present study was to evaluate the effects of switching from sitagliptin to vildagliptin, or vice versa, on 12-week glucose fluctuations using self-monitoring of blood glucose in the standard care setting. We conducted a multicenter, prospective, open-label controlled trial in Japanese patients with type 2 diabetes. Thirty-two patients were treated with vildagliptin (50 mg) twice daily or sitagliptin (50 mg) once daily and were allocated to one of two groups: vildagliptin treatment for 12 weeks before switching to sitagliptin for 12 weeks, or vice versa. Daily profiles of blood glucose were assessed several times during each treatment period, and the mean amplitude of glycemic excursions and M-value were calculated. Metabolic biomarkers such as hemoglobin A1c (HbA1c), glycated albumin, and 1,5-anhydroglucitol were also assessed. With vildagliptin treatment, mean amplitude of glycemic excursions was significantly improved compared with sitagliptin treatment (57.9 ± 22.2 vs. 68.9 ± 33.0 mg/dL; p=0.0045). M-value (p=0.019) and mean blood glucose (p=0.0021) were also lower with vildagliptin, as were HbA1c, glycated albumin, and 1,5-anhydroglucitol. There were no significant differences in other metabolic parameters evaluated. Reduction of daily blood glucose profile fluctuations by vildagliptin was superior to that of sitagliptin in Japanese patients with type 2 diabetes.

  10. Influence of hip and knee osteoarthritis on dynamic postural control parameters among older fallers.

    PubMed

    Mat, Sumaiyah; Ng, Chin Teck; Tan, Maw Pin

    2017-03-06

    To compare the relationship between postural control and knee and hip osteoarthritis in older adults with and without a history of falls. Fallers were those with ≥ 2 falls or 1 injurious fall over 12 months. Non-fallers were volunteers with no falls in the past year. Radiological evidence of osteoarthritis with no reported symptoms was considered "asymptomatic osteoarthritis", while "symptomatic osteoarthritis" was defined as radiographic osteoarthritis with pain or stiffness. Dynamic postural control was quantified with the limits of stability test measured on a balance platform (Neurocom® Balancemaster, California, USA). Parameters assessed were end-point excursion, maximal excursion, and directional control. A total of 102 older individuals, mean age 73 years (standard deviation 5.7) years were included. The association between falls and poor performance in maximal excursion and directional control was confounded by age and comorbidities. In the same linear equation model with falls, symptomatic osteoarthritis remained independently associated with poor end-point excursion (β-coefficient (95% confidence interval) -6.80 (-12.14 to -1.42)). Poor performance in dynamic postural control (maximal excursion and directional control) among fallers was not accounted for by hip/knee osteoarthritis, but was confounded by old age and comorbidities. Loss of postural control due to hip/knee osteoarthritis is not a risk factor for falls among community-dwelling older adults.

  11. Determining the Accuracy of Paleomagnetic Remanence and High-Resolution Chronostratigraphy for Sedimentary Rocks using Rock Magnetics

    NASA Astrophysics Data System (ADS)

    Kodama, K. P.

    2017-12-01

    The talk will consider two broad topics in rock magnetism and paleomagnetism: the accuracy of paleomagnetic remanence and the use of rock magnetics to measure geologic time in sedimentary sequences. The accuracy of the inclination recorded by sedimentary rocks is crucial to paleogeographic reconstructions. Laboratory compaction experiments show that inclination shallows on the order of 10˚-15˚. Corrections to the inclination can be made using the effects of compaction on the directional distribution of secular variation recorded by sediments or the anisotropy of the magnetic grains carrying the ancient remanence. A summary of all the compaction correction studies as of 2012 shows that 85% of sedimentary rocks studied have enjoyed some amount of inclination shallowing. Future work should also consider the effect of grain-scale strain on paleomagnetic remanence. High resolution chronostratigraphy can be assigned to a sedimentary sequence using rock magnetics to detect astronomically-forced climate cycles. The power of the technique is relatively quick, non-destructive measurements, the objective identification of the cycles compared to facies interpretations, and the sensitivity of rock magnetics to subtle changes in sedimentary source. An example of this technique comes from using rock magnetics to identify astronomically-forced climate cycles in three globally distributed occurrences of the Shuram carbon isotope excursion. The Shuram excursion may record the oxidation of the world ocean in the Ediacaran, just before the Cambrian explosion of metazoans. Using rock magnetic cyclostratigraphy, the excursion is shown to have the same duration (8-9 Myr) in southern California, south China and south Australia. Magnetostratigraphy of the rocks carrying the excursion in California and Australia shows a reversed to normal geomagnetic field polarity transition at the excursion's nadir, thus supporting the synchroneity of the excursion globally. Both results point to a primary depositional origin for the excursion, and strengthens the argument for oxidation of the world ocean in the Ediacaran. Future work must learn how global climate is encoded by rock magnetics, but our work to date suggests that variations in continental run-off are detected by rock magnetics.

  12. Peak-power limits on fiber amplifiers imposed by self-focusing

    NASA Astrophysics Data System (ADS)

    Farrow, Roger L.; Kliner, Dahv A. V.; Hadley, G. Ronald; Smith, Arlee V.

    2006-12-01

    We have numerically investigated the behavior of the fundamental mode of a step-index, multimode (MM) fiber as the optical power approaches the self-focusing limit (Pcrit). The analysis includes the effects of gain and bending (applicable to coiled fiber amplifiers). We find power-dependent, stationary solutions that propagate essentially without change at beam powers approaching Pcrit in straight and bent fibers. We show that in a MM fiber amplifier seeded with its fundamental eigenmode at powers ≪Pcrit, the transverse spatial profile adiabatically evolves through a continuum of stationary solutions as the beam is amplified toward Pcrit.

  13. On the suitability of fibre optical parametric amplifiers for use in all-optical agile photonic networks

    NASA Astrophysics Data System (ADS)

    Gryspolakis, Nikolaos

    The objective of this thesis is to investigate the suitability of fibre optical parametric amplifiers (FOPAs) for use in multi-channel, dynamic networks. First, we investigate their quasi-static behaviour in such an environment. We study the behaviour of a FOPA under realistic conditions and we examine the impact on the gain spectrum of channel addition for several different operating conditions and regimes. In particular, we examine the impact of surviving channel(s) position, input power and channel spacing. We see how these parameters affect the gain tilt as well as its dynamic characteristics, namely the generation of under or over-shoots at the transition point, possible dependence of rise and fall times on any of the aforementioned parameters and how the gain excursions depend on those parameters. For these studies we assume continuous wave operation for all signals. We observe that the gain spectrum changes are a function of the position and the spacing of the channels. We also find that the gain excursion can reach several dBs (up to 5 dB) in the case of channel add/drop and are heavily dependent on the position of the surviving channels. The channels located in the middle of the transmission band are more prone to channel add/drop-induced gain changes. Moreover, we investigate for the first time the FOPA dynamic behaviour in a packet switching scenario. This part of the study assumes that all but one channels normally vary in a packet-switched fashion. The remaining channel (probe channel) is expected to undergo gain variations due to the perturbation of the system experienced by the other channels. Furthermore, we consider several different scenarios for which the channels spacing, per channel input power (PCIP), variance of the power fluctuation and position of the probe channel will change. We find that when the FOPA operates near saturation the target gain is not achieved more than 50% of the time while the peak-to-peak gain excursions can exceed 1 dB. Next, we introduce modulated channels to the amplifier in order to compare their effect on the Bit Error Rate (BER) performance. We consider the impact on FOPAs when employing different modulation formats, such as RZ, NRZ and RZ-DPSK. Carefully selected modulation formats can improve BER performance and reduce the effects of cross-phase modulation, four wave mixing (FWM) products generation or dispersion (non-linear and linear inter-channel interference). Especially for the case of FOPAs, because of the ultra-fast interaction times of the FWM phenomenon, cross gain modulation can be a great deterrent for using FOPAs. We use RZ-DPSK in order to suppress the WDM signal crosstalk. Only by using RZ-DPSK, we obtain an improved receiver sensitivity of 5 dB when operating at 40 Gb/s. Finally, we investigate ways to mitigate such effects as the ones described above (gain excursions, gain tilt, etc.). We demonstrate that by using a ring configuration with optical feedback for the first time in FOPAs, we can achieve all-optical gain clamping (AOGC), mitigating gain excursions and attaining gain, independent of channel input power for a large range of PCIP. For example, with the use of AOGC, we reduce the add/drop-induced gain excursions from 4 dB to 0.6 dB. Also, by the combined use of AOGC and RZ-DPSK, we mitigate most of the aforementioned hindrances described above.

  14. The Neutral Islands during the Late Epoch of Reionization

    NASA Astrophysics Data System (ADS)

    Xu, Yidong; Yue, Bin; Chen, Xuelei

    2018-05-01

    The large-scale structure of the ionization field during the epoch of reionization (EoR) can be modeled by the excursion set theory. While the growth of ionized regions during the early stage are described by the ``bubble model'', the shrinking process of neutral regions after the percolation of the ionized region calls for an ``island model''. An excursion set based analytical model and a semi-numerical code (islandFAST) have been developed. The ionizing background and the bubbles inside the islands are also included in the treatment. With two kinds of absorbers of ionizing photons, i.e. the large-scale under-dense neutral islands and the small-scale over-dense clumps, the ionizing background are self-consistently evolved in the model.

  15. A Vendian-Cambrian boundary succession from the northwestern margin of the Siberian Platform: stratigraphy, palaeontology, chemostratigraphy and correlation

    NASA Technical Reports Server (NTRS)

    Bartley, J. K.; Pope, M.; Knoll, A. H.; Semikhatov, M. A.; Grotzinger, J. (Principal Investigator)

    1998-01-01

    Siberia contains several key reference sections for studies of biological and environmental evolution across the Proterozoic-Phanerozoic transition. The Platonovskaya Formation, exposed in the Turukhansk region of western Siberia, is an uppermost Proterozoic to Cambrian succession whose trace and body fossils place broad limits on the age of deposition, but do not permit detailed correlation with boundary successions elsewhere. In contrast, a striking negative carbon isotopic excursion in the lower part of the Platonovskaya Formation permits precise chemostratigraphic correlation with upper-most Yudomian successions in Siberia, and possibly worldwide. In addition to providing a tool for correlation, the isotopic excursion preserved in the Platonovskaya and contemporaneous successions documents a major biogeochemical event, likely involving the world ocean. The excursion coincides with the palaeontological breakpoint between Ediacaran- and Cambrian-style assemblages, suggesting a role for biogeochemical change in evolutionary events near the Proterozoic Cambrian boundary.

  16. A Vendian-Cambrian boundary succession from the northwestern margin of the Siberian Platform: stratigraphy, palaeontology, chemostratigraphy and correlation.

    PubMed

    Bartley, J K; Pope, M; Knoll, A H; Semikhatov, M A; Petrov PYu

    1998-07-01

    Siberia contains several key reference sections for studies of biological and environmental evolution across the Proterozoic-Phanerozoic transition. The Platonovskaya Formation, exposed in the Turukhansk region of western Siberia, is an uppermost Proterozoic to Cambrian succession whose trace and body fossils place broad limits on the age of deposition, but do not permit detailed correlation with boundary successions elsewhere. In contrast, a striking negative carbon isotopic excursion in the lower part of the Platonovskaya Formation permits precise chemostratigraphic correlation with upper-most Yudomian successions in Siberia, and possibly worldwide. In addition to providing a tool for correlation, the isotopic excursion preserved in the Platonovskaya and contemporaneous successions documents a major biogeochemical event, likely involving the world ocean. The excursion coincides with the palaeontological breakpoint between Ediacaran- and Cambrian-style assemblages, suggesting a role for biogeochemical change in evolutionary events near the Proterozoic Cambrian boundary.

  17. Excursion Processes Associated with Elliptic Combinatorics

    NASA Astrophysics Data System (ADS)

    Baba, Hiroya; Katori, Makoto

    2018-06-01

    Researching elliptic analogues for equalities and formulas is a new trend in enumerative combinatorics which has followed the previous trend of studying q-analogues. Recently Schlosser proposed a lattice path model in the square lattice with a family of totally elliptic weight-functions including several complex parameters and discussed an elliptic extension of the binomial theorem. In the present paper, we introduce a family of discrete-time excursion processes on Z starting from the origin and returning to the origin in a given time duration 2 T associated with Schlosser's elliptic combinatorics. The processes are inhomogeneous both in space and time and hence expected to provide new models in non-equilibrium statistical mechanics. By numerical calculation we show that the maximum likelihood trajectories on the spatio-temporal plane of the elliptic excursion processes and of their reduced trigonometric versions are not straight lines in general but are nontrivially curved depending on parameters. We analyze asymptotic probability laws in the long-term limit T → ∞ for a simplified trigonometric version of excursion process. Emergence of nontrivial curves of trajectories in a large scale of space and time from the elementary elliptic weight-functions exhibits a new aspect of elliptic combinatorics.

  18. Excursion Processes Associated with Elliptic Combinatorics

    NASA Astrophysics Data System (ADS)

    Baba, Hiroya; Katori, Makoto

    2018-04-01

    Researching elliptic analogues for equalities and formulas is a new trend in enumerative combinatorics which has followed the previous trend of studying q-analogues. Recently Schlosser proposed a lattice path model in the square lattice with a family of totally elliptic weight-functions including several complex parameters and discussed an elliptic extension of the binomial theorem. In the present paper, we introduce a family of discrete-time excursion processes on Z starting from the origin and returning to the origin in a given time duration 2T associated with Schlosser's elliptic combinatorics. The processes are inhomogeneous both in space and time and hence expected to provide new models in non-equilibrium statistical mechanics. By numerical calculation we show that the maximum likelihood trajectories on the spatio-temporal plane of the elliptic excursion processes and of their reduced trigonometric versions are not straight lines in general but are nontrivially curved depending on parameters. We analyze asymptotic probability laws in the long-term limit T → ∞ for a simplified trigonometric version of excursion process. Emergence of nontrivial curves of trajectories in a large scale of space and time from the elementary elliptic weight-functions exhibits a new aspect of elliptic combinatorics.

  19. Geomagnetic excursions in the Brunhes and Matuyama Chrons: Do they come in bunches?

    NASA Astrophysics Data System (ADS)

    Channell, J. E. T.

    2012-04-01

    Geomagnetic excursions, defined here as brief directional aberrations of the main dipole field outside the range of expected secular variation, remain controversial. Poorly-correlated records of apparent excursions from lavas and sediments can often be assigned to sampling artifacts, sedimentological phenomena, volcanic terrane effects, or local secular variation, rather than behavior of the main dipole field. Although records of magnetic excursions date from the 1960s, the number of Brunhes excursions in recent reviews of the subject have reached the 12-17 range, of which only about ~7 are adequately and/or consistently recorded. For the Matuyama Chron, the current inventory of excursions stands at about 10. The better quality excursion records, with reasonable age control, imply millennial-scale or even sub-millennial-scale durations. When "adequately" recorded, excursions are manifest as paired polarity reversals flanking virtual geomagnetic poles (VGPs) that reach high latitudes in the opposite hemisphere. At the young end of the excursion record, the Mono Lake (~33 ka) and Laschamp (~41 ka) excursions are well documented, although records of the former are not widely distributed. Several excursions younger than the Mono Lake excursion (at 17 ka and 25 ka) have recently been recorded in lavas and sediments, respectively. Is the 17-41 ka interval characterized by multiple excursions? Similarly, multiple excursions have been recorded in the 188-238 ka interval that encompasses records of the Iceland Basin excursion (~188 ka) and the Pringle Falls (PF) excursion. The PF excursion has been assigned ages in the 211-238 ka range. Does this mean that this interval is also characterized by several discrete excursions? The 500-600 ka interval incorporates not only the Big Lost excursion at ~565 ka, but also anomalous magnetization directions from lava flows, particularly in the West Eifel volcanics that yield mid-latitude northern-hemisphere VGPs with a range of Ar/Ar ages. The key question is whether such intervals of mid-latitude VGPs denote high-amplitude secular variation or inadequately recorded magnetic excursions. We propose that excursions characterized by high VGP latitudes in the opposite hemisphere should be termed Category 1 excursions, and those manifest by low/mid-latitude VGPs should be termed Category 2 excursions. In the future, improved records may "elevate" Category 2 excursions to Category 1. We do not view this subdivision of Category 1 and Category 2 excursions as necessarily a geomagnetic distinction, but possibly a distinction based on recording fidelity.

  20. Quaternary magnetic excursions recorded in marine sediments.

    NASA Astrophysics Data System (ADS)

    Channell, J. E. T.

    2017-12-01

    This year is the golden (50th) anniversary of the first documentation of a magnetic excursion, the Laschamp excursion in volcanics from the Chaine des Puys (Bonhommet and Babkine, 1967). The first recording of an excursion in sediments was from the Blake Outer Ridge (Smith and Foster, 1969). Magnetic excursions are directional aberrations of the geomagnetic field apparently involving short-lived reversal of the main dipole field. They have durations of a few kyrs, and are therefore rarely recorded in sediments with mean sedimentation rates <10 cm/kyr. Certain Brunhes-aged excursions are now well documented having been recorded in both marine sediments and in lavas (Laschamp excursion, 41 ka). Other excursions have not been adequately recorded in lavas, but have been widely recorded in marine and lake sediments (Iceland Basin excursion, 190 ka). The recording of excursions is fortuitous both in lava sequences and in marine sediments due to their millennial/centennial-scale duration, however, the global recording of the Laschamp and Iceland Basin excursions imply that excursions involve the main dipole field, are recorded synchronously over the globe, and are therefore important in stratigraphic correlation. The marine sediment record includes magnetic excursions at 26 ka (Rockall), 32 ka (Mono Lake), 41 ka (Laschamp), 115 ka (Blake), 190 ka (Iceland Basin), 238 ka (Pringle Falls?), 286 ka (Portuguese Orphan), 495 ka (Bermuda), 540 ka (Big Lost), 590 ka (La Palma), and 670 ka (Osaka Bay), implying at least 11 excursions in the Brunhes Chron. For the Matuyama Chron, excursions have been recorded in marine sediments at 868 ka (Kamikatsura?), 932 ka (Santa Rosa), 1051 ka (Intra-Jaramillo), 1115 ka (Punaruu), 1255 ka (Bjorn), 1476 ka (Gardar), 1580 ka (Gilsa), and 2737 ka (Porcupine). Excursions coincide with minima in relative paleointensity (RPI) records. Ages are from correlation of excursion records to oxygen isotope records in the same cores, and ice-volume calibration of the oxygen isotope template. The marine sediment record of excursions, combined with independent documentation of excursions in lavas with Ar/Ar age control, is progressively strengthening our knowledge of the excursion inventory in the Quaternary, and enhancing the importance of excursions and RPI in Quaternary stratigraphy.

  1. SPERT Destructive Test - I on Aluminum, Highly Enriched Plate Type Core

    ScienceCinema

    None

    2018-01-16

    SPERT - Special Power Excursion Reactor Tests Destructive Test number 1 On Aluminum, Highly Enriched Plate Type Core. A test studying the behavior of the reactor under destructive conditions on a light water moderated pool-type reactor with a plate-type core.

  2. PIC simulation of the vacuum power flow for a 5 terawatt, 5 MV, 1 MA pulsed power system

    NASA Astrophysics Data System (ADS)

    Liu, Laqun; Zou, Wenkang; Liu, Dagang; Guo, Fan; Wang, Huihui; Chen, Lin

    2018-03-01

    In this paper, a 5 Terawatt, 5 MV, 1 MA pulsed power system based on vacuum magnetic insulation is simulated by the particle-in-cell (PIC) simulation method. The system consists of 50 100-kV linear transformer drive (LTD) cavities in series, using magnetically insulated induction voltage adder (MIVA) technology for pulsed power addition and transmission. The pulsed power formation and the vacuum power flow are simulated when the system works in self-limited flow and load-limited flow. When the pulsed power system isn't connected to the load, the downstream magnetically insulated transmission line (MITL) works in the self-limited flow, the maximum of output current is 1.14 MA and the amplitude of voltage is 4.63 MV. The ratio of the electron current to the total current is 67.5%, when the output current reached the peak value. When the impedance of the load is 3.0 Ω, the downstream MITL works in the self-limited flow, the maximums of output current and the amplitude of voltage are 1.28 MA and 3.96 MV, and the ratio of the electron current to the total current is 11.7% when the output current reached the peak value. In addition, when the switches are triggered in synchronism with the passage of the pulse power flow, it effectively reduces the rise time of the pulse current.

  3. Influence of the cubic spectral phase of high-power laser pulses on their self-phase modulation

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

    Ginzburg, V N; Kochetkov, A A; Yakovlev, I V

    2016-02-28

    Spectral broadening of high-power transform-limited laser pulses under self-phase modulation in a medium with cubic nonlinearity is widely used to reduce pulse duration and to increase its power. It is shown that the cubic spectral phase of the initial pulse leads to a qualitatively different broadening of its spectrum: the spectrum has narrow peaks and broadening decreases. However, the use of chirped mirrors allows such pulses to be as effectively compressed as transform-limited pulses. (nonlinear optical phenomena)

  4. Design, fabrication, and testing of energy-harvesting thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Jovanovic, Velimir; Ghamaty, Saeid

    2006-03-01

    An energy-harvesting thermoelectric generator (TEG) is being developed to provide power for wireless sensors used in health monitoring of Navy machinery. TEGs are solid-state devices that convert heat directly into electricity without any moving parts. In this application, the TEGs utilize the heat transfer between shipboard waste heat sources and the ambient air to generate electricity. In order to satisfy the required small design volume of less than one cubic inch, Hi-Z is using its innovative thin-film Quantum Well (QW) thermoelectric technology that will provide a factor of four increase in efficiency and a large reduction in the device volume over the currently used bulk Bi IITe 3 based thermoelectics. QWs are nanostructured multi-layer films. These wireless sensors can be used to detect cracks, corrosion, impact damage, and temperature and vibration excursions as part of the Condition Based Maintenance (CBM) of the Navy ship machinery. The CBM of the ship machinery can be significantly improved by automating the process with the use of self-powered wireless sensors. These power-harvesting TEGs can be used to replace batteries as electrical power sources and to eliminate power cables and data lines. The first QW TEG module was fabricated and initial tests were successful. It is planned to conduct performance tests the entire prototype QW TEG device (consisting of the TEG module, housing, thermal insulation and the heat sink) in a simulated thermal environment of a Navy ship.

  5. Entry Dispersion Analysis for the Stardust Comet Sample Return Capsule

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Mitcheltree, Robert A.; Cheatwood, F. McNeil

    1997-01-01

    Stardust will be the first mission to return samples from beyond the Earth-Moon system. The sample return capsule, which is passively controlled during the fastest Earth entry ever, will land by parachute in Utah. The present study analyzes the entry, descent, and landing of the returning sample capsule. The effects of two aerodynamic instabilities are revealed (one in the high altitude free molecular regime and the other in the transonic/subsonic flow regime). These instabilities could lead to unacceptably large excursions in the angle-of-attack near peak heating and main parachute deployment, respectively. To reduce the excursions resulting from the high altitude instability, the entry spin rate of the capsule is increased. To stabilize the excursions from the transonic/subsonic instability, a drogue chute with deployment triggered by an accelerometer and timer is added prior to main parachute deployment. A Monte Carlo dispersion analysis of the modified entry (from which the impact of off-nominal conditions during the entry is ascertained) shows that the capsule attitude excursions near peak heating and drogue chute deployment are within Stardust program limits. Additionally, the size of the resulting 3-sigma landing ellipse is 83.5 km in downrange by 29.2 km in crossrange, which is within the Utah Test and Training Range boundaries.

  6. High-resolution record of the Laschamp geomagnetic excursion at the Blake-Bahama Outer Ridge

    NASA Astrophysics Data System (ADS)

    Bourne, Mark D.; Mac Niocaill, Conall; Thomas, Alex L.; Henderson, Gideon M.

    2013-12-01

    Geomagnetic excursions are brief deviations of the geomagnetic field from behaviour expected during `normal secular' variation. The Laschamp excursion at ˜41 ka was one such deviation. Previously published records suggest rapid changes in field direction and a concurrent substantial decrease in field intensity associated with this excursion. Accurate dating of excursions, and determination of their durations from multiple locations, is vital to our understanding of global field behaviour during these deviations. We present here high-resolution palaeomagnetic records of the Laschamp excursion obtained from two Ocean Drilling Program (ODP) Sites, 1061 and 1062 on the Blake-Bahama Outer Ridge (ODP Leg 172). High sedimentation rates (˜30-40 cm kyr-1) at these locations allow determination of transitional field behaviour during the excursion. Palaeomagnetic measurements of discrete samples from four cores reveal a single excursional feature, across an interval of 30 cm, associated with a broader palaeointensity low. We determine the age and duration of the Laschamp excursion using a stratigraphy linked to the δ18O record from the Greenland ice cores. This chronology dates the Laschamp excursion at the Blake Ridge to 41.3 ka. The excursion is characterized by rapid transitions (less than 200 yr) between stable normal polarity and a partially reversed polarity state. The palaeointensity record is in good agreement between the two sites, revealing two prominent minima. The first minimum is associated with the Laschamp excursion at 41 ka and the second corresponds to the Mono Lake excursion at ˜35.5 ka. We determine that the directional excursion during the Laschamp at this location was no longer than ˜400 yr, occurring within a palaeointensity minimum that lasted 2000 yr. The Laschamp excursion at this location is much shorter in duration than the Blake and Iceland Basin excursions.

  7. Beating the confusion limit: the necessity of high angular resolution for probing the physics of Sagittarius A* and its environment: opportunities for LINC-NIRVANA (LBT), GRAVITY (VLTI) and and METIS (E-ELT)

    NASA Astrophysics Data System (ADS)

    Eckart, A.; Sabha, N.; Witzel, G.; Straubmeier, C.; Shahzamanian, B.; Valencia-S., M.; García-Marín, Macarena; Horrobin, M.; Moser, L.; Zuther, J.; Fischer, S.; Rauch, C.; Rost, S.; Iserlohe, C.; Yazici, S.; Smajic, S.; Wiest, M.; Araujo-Hauck, C.; Wank, I.

    2012-07-01

    The super-massive 4 million solar mass black hole (SMBH) SgrA* shows variable emission from the millimeter to the X-ray domain. A detailed analysis of the infrared light curves allows us to address the accretion phenomenon in a statistical way. The analysis shows that the near-infrared flux density excursions are dominated by a single state power law, with the low states of SgrA* are limited by confusion through the unresolved stellar background. We show that for 8-10m class telescopes blending effects along the line of sight will result in artificial compact star-like objects of 0.5-1 mJy that last for about 3-4 years. We discuss how the imaging capabilities of GRAVITY at the VLTI, LINC-NIRVANA at the LBT and METIS at the E-ELT will contribute to the investigation of the low variability states of SgrA*.

  8. Speed And Power Control Of An Engine By Modulation Of The Load Torque

    DOEpatents

    Ziph, Benjamin; Strodtman, Scott; Rose, Thomas K

    1999-01-26

    A system and method of speed and power control for an engine in which speed and power of the engine is controlled by modulation of the load torque. The load torque is manipulated in order to cause engine speed, and hence power to be changed. To accomplish such control, the load torque undergoes a temporary excursion in the opposite direction of the desired speed and power change. The engine and the driven equipment will accelerate or decelerate accordingly as the load torque is decreased or increased, relative to the essentially fixed or constant engine torque. As the engine accelerates or decelerates, its power increases or decreases in proportion.

  9. Whole-body kinematic and dynamic response of restrained PMHS in frontal sled tests.

    PubMed

    Forman, Jason; Lessley, David; Kent, Richard; Bostrom, Ola; Pipkorn, Bengt

    2006-11-01

    The literature contains a wide range of response data describing the biomechanics of isolated body regions. Current data for the validation of frontal anthropomorphic test devices and human body computational models lack, however, a detailed description of the whole-body response to loading with contemporary restraints in automobile crashes. This study presents data from 14 frontal sled tests describing the physical response of postmortem human surrogates (PMHS) in the following frontal crash environments: A) (5 tests) driver position, force-limited 3-point belt plus airbag restraint (FLB+AB), 48 km/h deltaV. B) (3 tests) passenger position, FLB+AB restraint, 48 km/h deltaV. C) (3 tests) passenger position, standard (not force-limited) 3-point belt plus air bag restraint (SB+AB), 48 km/h deltaV. D) (3 tests) passenger position, standard 3-point belt restraint (SB), 29 km/h deltaV. Reported data include x-axis and z-axis (SAE occupant reference frame) accelerations of the head, spine (upper, middle, and lower), and pelvis; rate of angular rotation of the head about y-axis; displacements of the head, upper spine, pelvis and knee relative to the vehicle buck; and deformation contours of the upper and lower chest. A variety of kinematic trends are identified across the different test conditions, including a decrease in head and thorax excursion and a change in the nature of the excursion in the driver position compared to the passenger position. Despite this increase in forward excursion when compared to the driver's side FLB+AB tests, the passenger's side FLB+AB tests resulted in greater peak thoracic (T8) x-axis accelerations (passenger's side -29 g; driver's side -22 g;) and comparable maximum chest deflection (passenger's side - 23+/-3.1% of the undeformed chest depth; driver's side - 23+/-5.6%; ). In the 48 km/h passenger's side tests, the head excursion associated with the force-limiting belt system was approximately 15% greater than that for a standard belt system in tests that were otherwise identical. This was accompanied by a decrease in chest deflection of approximately 20% with the force-limiting system. Despite the decrease in test speed, the 29 km/h passenger's side tests with standard (not force-limiting) 3-point belt restraints resulted in maximum chest deflection (16+/-5.6% average) comparable to that observed in the 48 km/h, FLB+AB, driver's side tests (21+/-3.1% average). Finally, forward head excursion was slightly higher in the 29 km/h passenger's side tests (33+/-1.1 cm average) than in the 48 km/h driver's side tests (27+/-3.7 cm average), and was lower than that in the 48 km/h FLB+AB (58+/-4.4 cm average) and SB+AB (46+/-2.1 cm average) passenger's side tests.

  10. Heat removal capability of divertor coaxial tube assembly

    NASA Astrophysics Data System (ADS)

    Shibui, Masanao; Nakahira, Masataka; Tada, Eisuke; Takatsu, Hideyuki

    1994-05-01

    To deal with high power flowing in the divertor region, an advanced divertor concept with gas target has been proposed for use in ITER/EDA. The concept uses a divertor channel to remove the radiated power while allowing neutrals to recirculate. Candidate channel wall designs include a tube array design where many coaxial tubes are arranged in the toroidal direction to make louver. The coaxial tube consists of a Be protection tube encases many supply tubes wound helically around a return tube. V-alloy and hardened Cu-alloy have been proposed for use in the supply and return tubes. Some coolants have also been proposed for the design including pressurized He and liquid metals, because these coolants are consistent with the selection of coolants for the blanket and also meet the requirement of high temperature operation. In the coaxial tube design, the coolant area is restricted and brittle Be material is used under severe thermal cyclings. Thus, to obtain the coaxial tube with sufficient safety margin for the expected fusion power excursion, it is essential to understand its applicability limit. The paper discusses heat removal capability of the coaxial tube and recommends some design modifications.

  11. Advanced Power Conditioning System

    NASA Technical Reports Server (NTRS)

    Johnson, N. L.

    1971-01-01

    The second portion of the advanced power conditioning system development program is reported. Five 100-watt parallel power stages with majority-vote-logic feedback-regulator were breadboarded and tested to the design goals. The input voltage range was 22.1 to 57.4 volts at loads from zero to 500 watts. The maximum input ripple current was 200 mA pk-pk (not including spikes) at 511 watts load; the output voltage was 56V dc with a maximum change of 0.89 volts for all variations of line, load, and temperature; the maximum output ripple was 320 mV pk-pk at 512 watts load (dependent on filter capacitance value); the maximum efficiency was 93.9% at 212 watts and 50V dc input; the minimum efficiency was 87.2% at 80-watt load and 50V dc input; the efficiency was above 90% from 102 watts to 372 watts; the maximum excursion for an 80-watt load change was 2.1 volts with a recovery time of 7 milliseconds; and the unit performed within regulation limits from -20 C to +85 C. During the test sequence, margin tests and failure mode tests were run with no resulting degradation in performance.

  12. Steady-state phase error for a phase-locked loop subjected to periodic Doppler inputs

    NASA Technical Reports Server (NTRS)

    Chen, C.-C.; Win, M. Z.

    1991-01-01

    The performance of a carrier phase locked loop (PLL) driven by a periodic Doppler input is studied. By expanding the Doppler input into a Fourier series and applying the linearized PLL approximations, it is easy to show that, for periodic frequency disturbances, the resulting steady state phase error is also periodic. Compared to the method of expanding frequency excursion into a power series, the Fourier expansion method can be used to predict the maximum phase error excursion for a periodic Doppler input. For systems with a large Doppler rate fluctuation, such as an optical transponder aboard an Earth orbiting spacecraft, the method can be applied to test whether a lower order tracking loop can provide satisfactory tracking and thereby save the effect of a higher order loop design.

  13. Intermittent many-body dynamics at equilibrium

    NASA Astrophysics Data System (ADS)

    Danieli, C.; Campbell, D. K.; Flach, S.

    2017-06-01

    The equilibrium value of an observable defines a manifold in the phase space of an ergodic and equipartitioned many-body system. A typical trajectory pierces that manifold infinitely often as time goes to infinity. We use these piercings to measure both the relaxation time of the lowest frequency eigenmode of the Fermi-Pasta-Ulam chain, as well as the fluctuations of the subsequent dynamics in equilibrium. The dynamics in equilibrium is characterized by a power-law distribution of excursion times far off equilibrium, with diverging variance. Long excursions arise from sticky dynamics close to q -breathers localized in normal mode space. Measuring the exponent allows one to predict the transition into nonergodic dynamics. We generalize our method to Klein-Gordon lattices where the sticky dynamics is due to discrete breathers localized in real space.

  14. 75 FR 26841 - Petition for Waiver of Compliance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... definition of ``antiquated'' is being built prior to the end of World War II, even though this equipment is... equipment in steam and diesel locomotive powered excursion service on the entire trackage of the Great Lakes... accordance with part 211 of title 49 Code of Federal Regulations (CFR), notice is hereby given that the...

  15. Rain, Mud, Bikes and the Power of Relationships

    ERIC Educational Resources Information Center

    Willis, Judy

    2005-01-01

    In this article, the author describes her experiences on an annual teacher-student bike excursion at Santa Barbara Middle School in California. The trip, while plagued with rain, allowed her to develop closer relationships with her students that extended into the classroom. These continuing relationships have led to the establishment of greater…

  16. Transplanckian censorship and global cosmic strings

    NASA Astrophysics Data System (ADS)

    Dolan, Matthew J.; Draper, Patrick; Kozaczuk, Jonathan; Patel, Hiren

    2017-04-01

    Large field excursions are required in a number of axion models of inflation. These models also possess global cosmic strings, around which the axion follows a path mirroring the inflationary trajectory. Cosmic strings are thus an interesting theoretical laboratory for the study of transplanckian field excursions. We describe connections be-tween various effective field theory models of axion monodromy and study the classical spacetimes around their supercritical cosmic strings. For small decay constants f < M p and large winding numbers n > M p /f , the EFT is under control and the string cores undergo topological inflation, which may be either of exponential or power-law type. We show that the exterior spacetime is nonsingular and equivalent to a decompactifying cigar geometry, with the radion rolling in a potential generated by axion flux. Signals are able to circumnavigate infinite straight strings in finite but exponentially long time, t ˜ e Δ a/ M p . For finite loops of supercritical string in asymptotically flat space, we argue that if topological inflation occurs, then topological censorship implies transplanckian censorship, or that external observers are forbidden from threading the loop and observing the full excursion of the axion.

  17. Addendum to NuMI shielding assessment

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

    Vaziri, Kamran; /Fermilab

    2007-10-01

    The original safety assessment and the Safety Envelope for the NuMI beam line corresponds to 400 kW of beam power. The Main Injector is currently capable of and approved for producing 500 kW of beam power2. However, operation of the NuMI beam line at 400 kW of power brings up the possibility of an occasional excursion above 400 kW due to better than usual tuning in one of the machines upstream of the NuMI beam line. An excursion above the DOE approved Safety Envelope will constitute a safety violation. The purpose of this addendum is to evaluate the radiological issuesmore » and modifications required to operate the NuMI beam line at 500 kW. This upgrade will allow 400 kW operations with a reasonable safety margin. Configuration of the NuMI beam line, boundaries, safety system and the methodologies used for the calculations are as described in the original NuMI SAD. While most of the calculations presented in the original shielding assessment were based on Monte Carlo simulations, which were based on the design geometries, most of the results presented in this addendum are based on the measurements conducted by the AD ES&H radiation safety group.« less

  18. Space transfer concepts and analysis for exploration missions. Implementation plan and element description document. Volume 1: Major trades. Book 2: Draft final

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Topics addressed are: (1) an artificial gravity assessment study; (2) Mars mission transport vehicle (MTV)/Mars excursion vehicle (MEV) mission scenarios; (3) aerobrake issues; (4) equipment life and self-check; (5) earth-to-orbit (ETO) heavy lift launch vehicle (HLLV) definition trades; and (6) risk analysis.

  19. The statistical overlap theory of chromatography using power law (fractal) statistics.

    PubMed

    Schure, Mark R; Davis, Joe M

    2011-12-30

    The chromatographic dimensionality was recently proposed as a measure of retention time spacing based on a power law (fractal) distribution. Using this model, a statistical overlap theory (SOT) for chromatographic peaks is developed that estimates the number of peak maxima as a function of the chromatographic dimension, saturation and scale. Power law models exhibit a threshold region whereby below a critical saturation value no loss of peak maxima due to peak fusion occurs as saturation increases. At moderate saturation, behavior is similar to the random (Poisson) peak model. At still higher saturation, the power law model shows loss of peaks nearly independent of the scale and dimension of the model. The physicochemical meaning of the power law scale parameter is discussed and shown to be equal to the Boltzmann-weighted free energy of transfer over the scale limits. The scale is discussed. Small scale range (small β) is shown to generate more uniform chromatograms. Large scale range chromatograms (large β) are shown to give occasional large excursions of retention times; this is a property of power laws where "wild" behavior is noted to occasionally occur. Both cases are shown to be useful depending on the chromatographic saturation. A scale-invariant model of the SOT shows very simple relationships between the fraction of peak maxima and the saturation, peak width and number of theoretical plates. These equations provide much insight into separations which follow power law statistics. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. An investigation of the dynamic relationship between navicular drop and first metatarsophalangeal joint dorsal excursion

    PubMed Central

    Griffin, Nicole L; Miller, Charlotte; Schmitt, Daniel; D'Août, Kristiaan

    2013-01-01

    The modern human foot is a complex biomechanical structure that must act both as a shock absorber and as a propulsive strut during the stance phase of gait. Understanding the ways in which foot segments interact can illuminate the mechanics of foot function in healthy and pathological humans. It has been proposed that increased values of medial longitudinal arch deformation can limit metatarsophalangeal joint excursion via tension in the plantar aponeurosis. However, this model has not been tested directly in a dynamic setting. In this study, we tested the hypothesis that during the stance phase, subtalar pronation (stretching of the plantar aponeurosis and subsequent lowering of the medial longitudinal arch) will negatively affect the amount of first metatarsophalangeal joint excursion occurring at push-off. Vertical descent of the navicular (a proxy for subtalar pronation) and first metatarsophalangeal joint dorsal excursion were measured during steady locomotion over a flat substrate on a novel sample consisting of asymptomatic adult males and females, many of whom are habitually unshod. Least-squares regression analyses indicated that, contrary to the hypothesis, navicular drop did not explain a significant amount of variation in first metatarsophalangeal joint dorsal excursion. These results suggest that, in an asymptomatic subject, the plantar aponeurosis and the associated foot bones can function effectively within the normal range of subtalar pronation that takes place during walking gait. From a clinical standpoint, this study highlights the need for investigating the in vivo kinematic relationship between subtalar pronation and metatarsophalangeal joint dorsiflexion in symptomatic populations, and also the need to explore other factors that may affect the kinematics of asymptomatic feet. PMID:23600634

  1. Entry Trajectory Issues for the Stardust Sample Return Capsule

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Mitcheltree, Robert A.; Cheatwood, F. McNeil

    1999-01-01

    The Stardust mission was successfully launched on February 7, 1999. It will be the first mission to return samples from a comet. The sample return capsule, which is passively controlled during the fastest Earth entry ever, will land by parachute in Utah. The present study describes the analysis of the entry, descent, and landing of the returning sample capsule utilizing the final, launch configuration capsule mass properties. The effects of two aerodynamic instabilities are revealed (one in the high altitude free molecular regime and the other in the transonic/subsonic flow regime). These instabilities could lead to unacceptably large excursions in the angle-of-attack near peak heating and main parachute deployment, respectively. To reduce the excursions resulting from the high altitude instability, the entry spin rate of the capsule is increased. To stabilize the excursions from the transonic/subsonic instability, a drogue chute with deployment triggered by a gravity-switch and timer is added prior to main parachute deployment. A Monte Carlo dispersion analysis of the modified entry (from which the impact of off-nominal conditions during the entry is ascertained) predicts that the capsule attitude excursions near peak heating and drogue chute deployment are within Stardust mission limits. Additionally, the size of the resulting 3-sigma landing ellipse is 60.8 km in downrange by 19.9 km in crossrange, which is within the Utah Test and Training Range boundaries.

  2. Practices and Methods for Actualization of the Scientific Information in Art Excursions (Excursions and Cultural Heritage in the Contemporary World)

    ERIC Educational Resources Information Center

    Portnova, Tatiana V.

    2016-01-01

    The paper deals with various practices and methods for actualization of the scientific information in art excursions. The modern society is characterized by commitment to information richness. The range of cultural and historical materials used as the basis for art excursions is really immense. However if to consider the number of excursions with…

  3. Enhanced optical gain clamping for upstream packet based traffic on hybrid WDM/TDM-PON using fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Neto, B.; Klingler, A.; Reis, C.; Dionísio, R. P.; Nogueira, R. N.; Teixeira, A. L. J.; André, P. S.

    2011-03-01

    In this paper, we propose a method to mitigate the temporal power transients arising from Erbium doped fiber amplifiers (EDFAs) on packeted/bursty scenario. The technique, applicable on hybrid WDM/TDM-PON for extended reach, is based on a low power clamping provided by a distributed feedback (DFB) laser and a fiber Bragg grating (FBG). An improvement in the data signal Q factor was achieved keeping the clamping control signal with a low power, accompanied by a maximum reduction in the gain excursion of 1.12 dB.

  4. Mercury enrichment indicates volcanic triggering of Valanginian environmental change

    NASA Astrophysics Data System (ADS)

    Charbonnier, Guillaume; Morales, Chloé; Duchamp-Alphonse, Stéphanie; Westermann, Stéphane; Adatte, Thierry; Föllmi, Karl B.

    2017-01-01

    The Valanginian stage (Early Cretaceous) includes an episode of significant environmental changes, which are well defined by a positive δ13C excursion. This globally recorded excursion indicates important perturbations in the carbon cycle, which has tentatively been associated with a pulse in volcanic activity and the formation of the Paraná-Etendeka large igneous province (LIP). Uncertainties in existing age models preclude, however, its positive identification as a trigger of Valanginian environmental changes. Here we report that in Valanginian sediments recovered from a drill core in Wąwał (Polish Basin, Poland), and from outcrops in the Breggia Gorge (Lombardian Basin, southern Switzerland), and Orpierre and Angles (Vocontian Basin, SE France), intervals at or near the onset of the positive δ13C excursion are significantly enriched in mercury (Hg). The persistence of the Hg anomaly in Hg/TOC, Hg/phyllosilicate, and Hg/Fe ratios shows that organic-matter scavenging and/or adsorbtion onto clay minerals or hydrous iron oxides only played a limited role. Volcanic outgassing was most probably the primary source of the Hg enrichments, which demonstrate that an important magmatic pulse triggered the Valanginian environmental perturbations.

  5. Predictable "individual differences" in uptake and excretion of gases and lipid soluble vapours simulation study.

    PubMed Central

    Fiserova-Bergerova, V; Vlach, J; Cassady, J C

    1980-01-01

    A five-compartment pharmacokinetic model with two excretory pathways, exhalation and metabolism, based on first order kinetics is used to outline the effect of body build, pulmonary ventilation, and lipid content in blood on uptake, distribution, and clearance of low solubility gases and lipid soluble vapours during and after exposure. The model shows the extent that individual differences have on altering uptake and distribution, with consequent changes in blood concentration, rate of excretion, and toxicity, even when variations in these parameters are within physiological ranges. The model is also used to describe the concentration variation of inhaled substances in tissues of subjects exposed to concentrations with permitted excursions. During the same course of exposure, the tissue concentrations of low solubility gases fluctuate much more than tissue concentrations of lipid soluble vapours. The fluctuation is reduced by metabolism of inhaled substance. These conclusions are recommended for consideration whenever evaluating the effect of excursions above the threshold limit values used in the control of industrial exposures (by excursion factors). PMID:7370192

  6. A 5 nW Quasi-Linear CMOS Hot-Electron Injector for Self-Powered Monitoring of Biomechanical Strain Variations.

    PubMed

    Zhou, Liang; Abraham, Adam C; Tang, Simon Y; Chakrabartty, Shantanu

    2016-12-01

    Piezoelectricity-driven hot-electron injectors (p-HEI) are used for self-powered monitoring of mechanical activity in biomechanical implants and structures. Previously reported p-HEI devices operate by harvesting energy from a piezoelectric transducer to generate current and voltage references which are then used for initiating and controlling the process of hot-electron injection. As a result, the minimum energy required to activate the device is limited by the power requirements of the reference circuits. In this paper we present a p-HEI device that operates by directly exploiting the self-limiting capability of an energy transducer when driving the process of hot-electron injection in a pMOS floating-gate transistor. As a result, the p-HEI device can activate itself at input power levels less than 5 nW. Using a prototype fabricated in a 0.5- [Formula: see text] bulk CMOS process we validate the functionality of the proposed injector and show that for a fixed input power, its dynamics is quasi-linear with respect to time. The paper also presents measurement results using a cadaver phantom where the fabricated p-HEI device has been integrated with a piezoelectric transducer and is used for self-powered monitoring of mechanical activity.

  7. Analysis of the SL-1 Accident Using RELAPS5-3D

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

    Francisco, A.D. and Tomlinson, E. T.

    2007-11-08

    On January 3, 1961, at the National Reactor Testing Station, in Idaho Falls, Idaho, the Stationary Low Power Reactor No. 1 (SL-1) experienced a major nuclear excursion, killing three people, and destroying the reactor core. The SL-1 reactor, a 3 MW{sub t} boiling water reactor, was shut down and undergoing routine maintenance work at the time. This paper presents an analysis of the SL-1 reactor excursion using the RELAP5-3D thermal-hydraulic and nuclear analysis code, with the intent of simulating the accident from the point of reactivity insertion to destruction and vaporization of the fuel. Results are presented, along with amore » discussion of sensitivity to some reactor and transient parameters (many of the details are only known with a high level of uncertainty).« less

  8. Strategies adopted by younger and older adults while operating a non-pedal tricycle.

    PubMed

    Calve, Tatiane; Russo Júnior, Douglas Vicente; Barela, Ana Maria Forti

    Exercises that could prevent gait impairment of older adults should be implemented in such a way that practitioners can keep motivation and adherence independent of older adults fitness levels. This study describes how younger and older adults use a non-pedal tricycle to transport their bodies along a pathway. Nine younger (24±4.9y) and nine older (66±4.0y) adults participated in this study. They moved along a straight pathway at a self-selected comfortable speed with reflective markers on their main lower limb landmarks. A computerized gait analysis system with infrared cameras was used to obtain kinematic data to calculate spatial-temporal parameters and lower limb angles. Overall, participants from both groups were able to perform the task moving at a similar mean speed, with similar stride length and ankle joint excursion. Older adults had higher cadence (mean difference of 17steps/min; 95% CI=0.99-1.15) and hip excursion (mean difference of 12°; 95% CI=28-33), longer stance duration (mean difference of 3.4%; 95% CI=56.2-59.5), and lower knee excursion (mean difference of 6°; 95% CI=47.9-53.8) than younger adults. Older adults were able to transport their body with a non-pedal tricycle with more hip and less knee excursion than younger adults. Professionals that work with the older population should look at and take into consideration the use of non-pedal tricycles in exercise protocols and investigate the long-term impacts. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

  9. Scalar excursions in large-eddy simulations

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

    Matheou, Georgios; Dimotakis, Paul E.

    Here, the range of values of scalar fields in turbulent flows is bounded by their boundary values, for passive scalars, and by a combination of boundary values, reaction rates, phase changes, etc., for active scalars. The current investigation focuses on the local conservation of passive scalar concentration fields and the ability of the large-eddy simulation (LES) method to observe the boundedness of passive scalar concentrations. In practice, as a result of numerical artifacts, this fundamental constraint is often violated with scalars exhibiting unphysical excursions. The present study characterizes passive-scalar excursions in LES of a shear flow and examines methods formore » diagnosis and assesment of the problem. The analysis of scalar-excursion statistics provides support of the main hypothesis of the current study that unphysical scalar excursions in LES result from dispersive errors of the convection-term discretization where the subgrid-scale model (SGS) provides insufficient dissipation to produce a sufficiently smooth scalar field. In the LES runs three parameters are varied: the discretization of the convection terms, the SGS model, and grid resolution. Unphysical scalar excursions decrease as the order of accuracy of non-dissipative schemes is increased, but the improvement rate decreases with increasing order of accuracy. Two SGS models are examined, the stretched-vortex and a constant-coefficient Smagorinsky. Scalar excursions strongly depend on the SGS model. The excursions are significantly reduced when the characteristic SGS scale is set to double the grid spacing in runs with the stretched-vortex model. The maximum excursion and volume fraction of excursions outside boundary values show opposite trends with respect to resolution. The maximum unphysical excursions increase as resolution increases, whereas the volume fraction decreases. The reason for the increase in the maximum excursion is statistical and traceable to the number of grid points (sample size) which increases with resolution. In contrast, the volume fraction of unphysical excursions decreases with resolution because the SGS models explored perform better at higher grid resolution.« less

  10. Scalar excursions in large-eddy simulations

    DOE PAGES

    Matheou, Georgios; Dimotakis, Paul E.

    2016-08-31

    Here, the range of values of scalar fields in turbulent flows is bounded by their boundary values, for passive scalars, and by a combination of boundary values, reaction rates, phase changes, etc., for active scalars. The current investigation focuses on the local conservation of passive scalar concentration fields and the ability of the large-eddy simulation (LES) method to observe the boundedness of passive scalar concentrations. In practice, as a result of numerical artifacts, this fundamental constraint is often violated with scalars exhibiting unphysical excursions. The present study characterizes passive-scalar excursions in LES of a shear flow and examines methods formore » diagnosis and assesment of the problem. The analysis of scalar-excursion statistics provides support of the main hypothesis of the current study that unphysical scalar excursions in LES result from dispersive errors of the convection-term discretization where the subgrid-scale model (SGS) provides insufficient dissipation to produce a sufficiently smooth scalar field. In the LES runs three parameters are varied: the discretization of the convection terms, the SGS model, and grid resolution. Unphysical scalar excursions decrease as the order of accuracy of non-dissipative schemes is increased, but the improvement rate decreases with increasing order of accuracy. Two SGS models are examined, the stretched-vortex and a constant-coefficient Smagorinsky. Scalar excursions strongly depend on the SGS model. The excursions are significantly reduced when the characteristic SGS scale is set to double the grid spacing in runs with the stretched-vortex model. The maximum excursion and volume fraction of excursions outside boundary values show opposite trends with respect to resolution. The maximum unphysical excursions increase as resolution increases, whereas the volume fraction decreases. The reason for the increase in the maximum excursion is statistical and traceable to the number of grid points (sample size) which increases with resolution. In contrast, the volume fraction of unphysical excursions decreases with resolution because the SGS models explored perform better at higher grid resolution.« less

  11. 25 CFR 518.9 - Are any of the investigative or enforcement powers of the Commission limited by the issuance of a...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Commission limited by the issuance of a certificate of self-regulation? 518.9 Section 518.9 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR GENERAL PROVISIONS SELF REGULATION OF CLASS II... issuance of a certificate of self-regulation? No. Subject to the provisions of 25 U.S.C. 2710(c)(5)(A) the...

  12. Interhemispheric difference of pallidal local field potential activity in cervical dystonia.

    PubMed

    Lee, Jung Ryun; Kiss, Zelma H T

    2014-03-01

    Cervical dystonia (CD) produces involuntary neck muscle contractions that result in abnormal and often asymmetrical postures of the head and neck. Basal ganglia oscillatory activity in the 3-12 Hz band correlating with involuntary muscle activity suggests a role in the pathophysiology of primary dystonia. Despite the asymmetrical postures seen with CD, no comparison of interhemispheric differences of pallidal local field potential (LFP) activity has been reported. The aim of this study was to examine the interhemispheric differences of LFP power in globus pallidus interna (GPi) in CD patients and compare these with their predominant head excursion identified as torticollis, laterocollis and retrocollis. LFPs were recorded from bilateral GPi in 11 patients with CD using microelectrodes during deep brain stimulation surgery. LFP power was measured in right and left GPi separately. The mean percentage of total GPi LFP power in 4-30 Hz frequency band on each brain side was determined and related to their predominant CD symptoms. Interhemispheric difference in the mean percentage of LFP power in 4-12 Hz and 13-30 Hz band frequencies was found in patients with torticollis and laterocollis regardless of excursion direction. However, patients with retrocollis did not show interhemispheric difference in LFP activity in any band frequency. Interhemispheric differences in synchronisation of pallidal LFP activity in 4-12 Hz and 13-30 Hz bands are related to the CD clinical condition, suggesting that these frequencies are important in the pathophysiology of dystonia.

  13. Probing the Natural World, Level III, Record Book, Student Guide: What's Up? Intermediate Science Curriculum Study.

    ERIC Educational Resources Information Center

    Bonar, John R., Ed.; Hathway, James A., Ed.

    This is the student's edition of the Record Book for the unit "What's Up" of the Intermediate Science Curriculum Study (ISCS) for level III students (grade 9). Space is provided for answers to the questions from the student text as well as for the optional excursions and the self evaluation. An introductory note to the student explains…

  14. Multipathway modulation of exercise and glucose stress effects upon GH secretion in healthy men.

    PubMed

    Veldhuis, Johannes D; Olson, Thomas P; Takahashi, Paul Y; Miles, John M; Joyner, Michael J; Yang, Rebecca J; Wigham, Jean

    2015-09-01

    Exercise evokes pulsatile GH release followed by autonegative feedback, whereas glucose suppresses GH release followed by rebound-like GH release (feedforward escape). Here we test the hypothesis that age, sex steroids, insulin, body composition and physical power jointly determine these dynamic GH responses. This was a prospectively randomized glucose-blinded study conducted in the Mayo Center for Advancing Translational Sciences in healthy men ages 19-77 years (N=23). Three conditions, fasting/rest/saline, fasting/exercise/saline and fasting/rest/iv glucose infusions, were used to drive GH dynamics during 10-min blood sampling for 6h. Linear correlation analysis was applied to relate peak/nadir GH dynamics to age, sex steroids, insulin, CT-estimated abdominal fat and physical power (work per unit time). Compared with the fasting/rest/saline (control) day, fasting/exercise/saline infusion evoked peak GH within 1h, followed by negative feedback 3-5h later. The dynamic GH excursion was strongly (R(2)=0.634) influenced by (i) insulin negatively (P=0.011), (ii) power positively (P=0.0008), and (iii) E2 positively (P=0.001). Dynamic glucose-modulated GH release was determined by insulin negatively (P=0.0039) and power positively (P=0.0034) (R(2)=0.454). Under rest/saline, power (P=0.031) and total abdominal fat (P=0.012) (R(2)=0.267) were the dominant correlates of GH excursions. In healthy men, dynamic GH perturbations induced by exercise and glucose are strongly related to physical power, insulin, estradiol, and body composition, thus suggesting a network of regulatory pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. 29 CFR 1910.1001 - Asbestos.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... regulated areas. Building/facility owner is the legal entity, including a lessee, which exercises control... education, training, and experience to anticipate, recognize, evaluate and develop controls for occupational... appendix A to this section, or by an equivalent method. (2) Excursion limit. The employer shall ensure that...

  16. 29 CFR 1910.1001 - Asbestos.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... regulated areas. Building/facility owner is the legal entity, including a lessee, which exercises control... education, training, and experience to anticipate, recognize, evaluate and develop controls for occupational... appendix A to this section, or by an equivalent method. (2) Excursion limit. The employer shall ensure that...

  17. The conformal limit of inflation in the era of CMB polarimetry

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

    Pajer, Enrico; Wijck, Jaap V.S. van; Pimentel, Guilherme L., E-mail: enrico.pajer@gmail.com, E-mail: g.leitepimentel@uva.nl, E-mail: j.v.s.vanwijck@uu.nl

    2017-06-01

    We argue that the non-detection of primordial tensor modes has taught us a great deal about the primordial universe. In single-field slow-roll inflation, the current upper bound on the tensor-to-scalar ratio, r <0.07 (95% CL), implies that the Hubble slow-roll parameters obey ε||η , and therefore establishes the existence of a new hierarchy. We dub this regime the conformal limit of (slow-roll) inflation, and show that it includes Starobinsky-like inflation as well as all viable single-field models with a sub-Planckian field excursion. In this limit, all primordial correlators are constrained by the full conformal group to leading non-trivial order inmore » slow-roll. This fixes the power spectrum and the full bispectrum, and leads to the ''conformal'' shape of non-Gaussianity. The size of non-Gaussianity is related to the running of the spectral index by a consistency condition, and therefore it is expected to be small. In passing, we clarify the role of boundary terms in the ζ action, the order to which constraint equations need to be solved, and re-derive our results using the Wheeler-deWitt formalism.« less

  18. Mid-Brunhes magnetic excursions in marine isotope stages 9, 13, 14, and 15 (286, 495, 540, and 590 ka) at North Atlantic IODP Sites U1302/3, U1305, and U1306

    NASA Astrophysics Data System (ADS)

    Channell, J. E. T.

    2017-02-01

    Integrated Ocean Drilling Program (IODP) Site U1302/3 (Orphan Knoll, off Newfoundland) recorded magnetic excursions in marine isotope stages (MIS) 9a (at 286 ka) and 13a (at 495 ka). Sites U1306 and U1305 (Eirik Drift, off SE Greenland) record excursions in MIS 14a/b (at 540 ka) and 15b/c (at 590 ka). In the excursion intervals, magnetic measurements of continuous "u-channel" samples from multiple holes within site are augmented by measurements of cubic (8 cm3) discrete samples. The excursions lie in relative paleointensity (RPI) minima at each site and in RPI reference stacks, and correspond to dated intervals of 10Be overproduction in other deep-sea sediment records. Although observed at multiple holes at each site, and from u-channel and discrete samples, the excursions are not observed at all three sites, and often at only one of the three sites. Sporadic recording of these magnetic excursions, and excursions in general, is attributed to a combination of filtering by the process of acquisition of detrital remanent magnetization (DRM), postdepositional overprint of weak excursion magnetizations, the millennial or even centennial duration of directional excursions, and nonuniform sedimentation rates at these timescales in North Atlantic sediment drifts.

  19. Power and energy computational models for the design and simulation of hybrid-electric combat vehicles

    NASA Astrophysics Data System (ADS)

    Smith, Wilford; Nunez, Patrick

    2005-05-01

    This paper describes the work being performed under the RDECOM Power and Energy (P&E) program (formerly the Combat Hybrid Power System (CHPS) program) developing hybrid power system models and integrating them into larger simulations, such as OneSAF, that can be used to find duty cycles to feed designers of hybrid power systems. This paper also describes efforts underway to link the TARDEC P&E System Integration Lab (SIL) in San Jose CA to the TARDEC Ground Vehicle Simulation Lab (GVSL) in Warren, MI. This linkage is being performed to provide a methodology for generating detailed driver profiles for use in the development of vignettes and mission profiles for system design excursions.

  20. Experimental demonstration of fresh bunch self-seeding in an X-ray free electron laser

    DOE PAGES

    Emma, C.; Lutman, A.; Guetg, M. W.; ...

    2017-04-10

    Here, we report the generation of ultrahigh brightness X-ray pulses using the Fresh Bunch Self-Seeding (FBSS) method in an X-ray Free Electron Laser (XFEL). The FBSS method uses two different electron slices or bunches, one to generate the seed and the other to amplify it after the monochromator. This method circumvents the trade-off between the seed power and electron slice energy spread, which limits the efficiency of regular self-seeded FELs. The experiment, the performance of which is limited by existing hardware, shows FBSS feasibility, generating 5.5 keV photon pulses which are 9 fs long and of 7.3 ×10 –5 bandwidthmore » and 50 GW power. FBSS performance is compared with Self Amplified Spontaneous Emission/self-seeding performance, measuring a brightness increase of twelve/two times, respectively. In an optimized XFEL, FBSS can increase the peak power a hundred times more than state-of-the-art to multi-TW, opening new research areas for nonlinear science and single molecule imaging.« less

  1. An Internet-based virtual reality intervention for enhancing self-esteem in women with disabilities: Results of a feasibility study.

    PubMed

    Nosek, Margaret A; Robinson-Whelen, Susan; Hughes, Rosemary B; Nosek, Thomas M

    2016-11-01

    To examine the feasibility of an online self-esteem enhancement group program for women with disabilities. A sample of 19 racially and ethnically diverse, community-living women with physical disabilities, 22 to 61 years old, participated in a 7-session interactive group intervention (extending Hughes et al., 2004) in the 3-D, immersive, virtual environment of SecondLife.com, using avatars with voice and text communication. Baseline and postintervention questionnaires were administered online. Criteria for determining feasibility were (a) enrollment, (b) engagement, (c) acceptability, and (d) improvement on measures of self-esteem, depression, self-efficacy, and social support. We attained our enrollment goal and engagement exceeded expectations. Acceptability was positive; participants gave "helpful" and "enjoyable" ratings of 3.21 and 3.27, respectively, (mean on a 1 to 4 Likert scale, where 4 = high) to 5 intervention components-session materials, group sharing and discussion, relaxation exercises, action planning, and group excursions. Significant increases from baseline to postintervention were found on the Rosenberg Self-Esteem Scale (p = .02; Cohen's d = .60) and the Center for Epidemiologic Studies Depression Scale-10 (p = .005; Cohen's d = .74), with a trend toward significance on the Generalized Self-Efficacy Scale (p = .08; Cohen's d = .42). The intervention did not significantly affect the measure of social support. An intervention to enhance self-esteem may have a corollary benefit on depressive symptomatology. Offering psycho-educational, small group interventions using online virtual worlds shows promise for circumventing disability-related and environmental barriers to accessing mental health services experienced by women with mobility limitations, and should undergo further development and testing. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  2. Effect of African- and European-American maternal attitudes and limit-setting strategies on children's self-regulation.

    PubMed

    LeCuyer, Elizabeth A; Swanson, Dena P; Cole, Robert; Kitzman, Harriet

    2011-12-01

    The effect of maternal attitudes and limit-setting strategies on children's self-regulation (measured as committed compliance) was compared in 151 African-American (AA) and 108 European-American (EA) mothers and their 3-year-old children. There were no ethnic differences in children's compliance, however ethnicity moderated the relationship between maternal authoritarian attitudes and children's compliance. Higher authoritarian attitudes predicted less children's compliance in the EA sample, but greater compliance in the AA sample. Observational limit-setting data revealed that in both ethnic groups, maternal authoritarian attitudes influenced children's self-regulation through maternal use of lower-power (gentle) verbal strategies, fewer physical strategies, and judicious use of higher-power verbal strategies. The findings indicate that the meaning and purpose of authoritarian attitudes varies across these mothers' socio-cultural contexts. Copyright © 2011 Wiley Periodicals, Inc.

  3. 75 FR 45671 - Submission for OMB Review: Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-03

    ... previously approved collection. Title of Collection: Asbestos in General Industry (29 CFR 1910.1001). OMB... hazardous asbestos exposure. Asbestos exposure results in asbestosis, an emphysema-like condition; lung... requirement to prevent release of airborne asbestos above the time-weighted average and excursion limit. Other...

  4. Linear and nonlinear thermodynamics of a kinetic heat engine with fast transformations

    NASA Astrophysics Data System (ADS)

    Cerino, Luca; Puglisi, Andrea; Vulpiani, Angelo

    2016-04-01

    We investigate a kinetic heat engine model composed of particles enclosed in a box where one side acts as a thermostat and the opposite side is a piston exerting a given pressure. Pressure and temperature are varied in a cyclical protocol of period τ : their relative excursions, δ and ɛ , respectively, constitute the thermodynamic forces dragging the system out of equilibrium. The analysis of the entropy production of the system allows us to define the conjugated fluxes, which are proportional to the extracted work and the consumed heat. In the limit of small δ and ɛ the fluxes are linear in the forces through a τ -dependent Onsager matrix whose off-diagonal elements satisfy a reciprocal relation. The dynamics of the piston can be approximated, through a coarse-graining procedure, by a Klein-Kramers equation which—in the linear regime—yields analytic expressions for the Onsager coefficients and the entropy production. A study of the efficiency at maximum power shows that the Curzon-Ahlborn formula is always an upper limit which is approached at increasing values of the thermodynamic forces, i.e., outside of the linear regime. In all our analysis the adiabatic limit τ →∞ and the the small-force limit δ ,ɛ →0 are not directly related.

  5. Spiral Transformation for High-Resolution and Efficient Sorting of Optical Vortex Modes.

    PubMed

    Wen, Yuanhui; Chremmos, Ioannis; Chen, Yujie; Zhu, Jiangbo; Zhang, Yanfeng; Yu, Siyuan

    2018-05-11

    Mode sorting is an essential function for optical multiplexing systems that exploit the orthogonality of the orbital angular momentum mode space. The familiar log-polar optical transformation provides a simple yet efficient approach whose resolution is, however, restricted by a considerable overlap between adjacent modes resulting from the limited excursion of the phase along a complete circle around the optical vortex axis. We propose and experimentally verify a new optical transformation that maps spirals (instead of concentric circles) to parallel lines. As the phase excursion along a spiral in the wave front of an optical vortex is theoretically unlimited, this new optical transformation can separate orbital angular momentum modes with superior resolution while maintaining unity efficiency.

  6. Spiral Transformation for High-Resolution and Efficient Sorting of Optical Vortex Modes

    NASA Astrophysics Data System (ADS)

    Wen, Yuanhui; Chremmos, Ioannis; Chen, Yujie; Zhu, Jiangbo; Zhang, Yanfeng; Yu, Siyuan

    2018-05-01

    Mode sorting is an essential function for optical multiplexing systems that exploit the orthogonality of the orbital angular momentum mode space. The familiar log-polar optical transformation provides a simple yet efficient approach whose resolution is, however, restricted by a considerable overlap between adjacent modes resulting from the limited excursion of the phase along a complete circle around the optical vortex axis. We propose and experimentally verify a new optical transformation that maps spirals (instead of concentric circles) to parallel lines. As the phase excursion along a spiral in the wave front of an optical vortex is theoretically unlimited, this new optical transformation can separate orbital angular momentum modes with superior resolution while maintaining unity efficiency.

  7. Bound on largest r ∼< 0.1 from sub-Planckian excursions of inflaton

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

    Chatterjee, Arindam; Mazumdar, Anupam, E-mail: arindam@hri.res.in, E-mail: a.mazumdar@lancaster.ac.uk

    2015-01-01

    In this paper we will discuss the range of large tensor to scalar ratio, r, obtainable from a sub-Planckian excursion of a single, slow roll driven inflaton field. In order to obtain a large r for such a scenario one has to depart from a monotonic evolution of the slow roll parameters in such a way that one still satisfies all the current constraints of \\texttt(Planck), such as the scalar amplitude, the tilt in the scalar power spectrum, running and running of the tilt close to the pivot scale. Since the slow roll parameters evolve non-monotonically, we will also considermore » the evolution of the power spectrum on the smallest scales, i.e. at P{sub s}(k ∼ 10{sup 16} Mpc{sup −1})∼< 10{sup −2}, to make sure that the amplitude does not become too large. All these constraints tend to keep the tensor to scalar ratio, r ∼< 0.1. We scan three different kinds of potential for supersymmetric flat directions and obtain the benchmark points which satisfy all the constraints. We also show that it is possible to go beyond r ∼> 0.1 provided we relax the upper bound on the power spectrum on the smallest scales.« less

  8. Rapid directional changes associated with a 6.5 kyr-long Blake geomagnetic excursion at the Blake-Bahama Outer Ridge

    NASA Astrophysics Data System (ADS)

    Bourne, Mark; Mac Niocaill, Conall; Thomas, Alex L.; Knudsen, Mads Faurschou; Henderson, Gideon M.

    2012-06-01

    Geomagnetic excursions are recognized as intrinsic features of the Earth's magnetic field. High-resolution records of field behaviour, captured in marine sedimentary cores, present an opportunity to determine the temporal and geometric character of the field during geomagnetic excursions and provide constraints on the mechanisms producing field variability. We present here the highest resolution record yet published of the Blake geomagnetic excursion (∼125 ka) measured in three cores from Ocean Drilling Program (ODP) Site 1062 on the Blake-Bahama Outer Ridge. The Blake excursion has a controversial structure and timing but these cores have a sufficiently high sedimentation rate (∼10 cm ka-1) to allow detailed reconstruction of the field behaviour at this site during the excursion. Palaeomagnetic measurements of the cores reveal rapid transitions (<500 yr) between the contemporary stable normal polarity and a completely reversed state of long duration which spans a stratigraphic interval of 0.7 m. We determine the duration of the reversed state during the Blake excursion using oxygen isotope stratigraphy, combined with 230Th excess measurements to assess variations in the sedimentation rates through the sections of interest. This provides an age and duration for the Blake excursion with greater accuracy and with constrained uncertainty. We date the directional excursion as falling between 129 and 122 ka with a duration for the deviation of 6.5±1.3 kyr. The long duration of this interval and the fully reversed field suggest the existence of a pseudo-stable, reversed dipole field component during the excursion and challenge the idea that excursions are always of short duration.

  9. Midtarsal locking, the windlass mechanism, and running strike pattern: A kinematic and kinetic assessment.

    PubMed

    Bruening, Dustin A; Pohl, Michael B; Takahashi, Kota Z; Barrios, Joaquin A

    2018-05-17

    Changes in running strike pattern affect ankle and knee mechanics, but little is known about the influence of strike pattern on the joints distal to the ankle. The purpose of this study was to explore the effects of forefoot strike (FFS) and rearfoot strike (RFS) running patterns on foot kinematics and kinetics, from the perspectives of the midtarsal locking theory and the windlass mechanism. Per the midtarsal locking theory, we hypothesized that the ankle would be more inverted in early stance when using a FFS, resulting in decreased midtarsal joint excursions and increased dynamic stiffness. Associated with a more engaged windlass mechanism, we hypothesized that a FFS would elicit increased metatarsophalangeal joint excursions and negative work in late stance. Eighteen healthy female runners ran overground with both FFS and RFS patterns. Instrumented motion capture and a validated multi-segment foot model were used to analyze midtarsal and metatarsophalangeal joint kinematics and kinetics. During early stance in FFS the ankle was more inverted, with concurrently decreased midtarsal eversion (p < 0.001) and abduction excursions (p = 0.003) but increased dorsiflexion excursion (p = 0.005). Dynamic midtarsal stiffness did not differ (p = 0.761). During late stance in FFS, metatarsophalangeal extension was increased (p = 0.009), with concurrently increased negative work (p < 0.001). In addition, there was simultaneously increased midtarsal positive work (p < 0.001), suggesting enhanced power transfer in FFS. Clear evidence for the presence of midtarsal locking was not observed in either strike pattern during running. However, the windlass mechanism appeared to be engaged to a greater extent during FFS. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Relative fascicle excursion effects on dynamic strength generation during gait in children with cerebral palsy.

    PubMed

    Martín Lorenzo, T; Lerma Lara, S; Martínez-Caballero, I; Rocon, E

    2015-10-01

    Evaluation of muscle structure gives us a better understanding of how muscles contribute to force generation which is significantly altered in children with cerebral palsy (CP). While most muscle structure parameters have shown to be significantly correlated to different expressions of strength development in children with CP and typically developing (TD) children, conflicting results are found for muscle fascicle length. Muscle fascicle length determines muscle excursion and velocity, and contrary to what might be expected, correlations of fascicle length to rate of force development have not been found for children with CP. The lack of correlation between muscle fascicle length and rate of force development in children with CP could be due, on the one hand, to the non-optimal joint position adopted for force generation on the isometric strength tests as compared to the position of TD children. On the other hand, the lack of correlation could be due to the erroneous assumption that muscle fascicle length is representative of sarcomere length. Thus, the relationship between muscle architecture parameters reflecting sarcomere length, such as relative fascicle excursions and dynamic power generation, should be assessed. Understanding of the underlying mechanisms of weakness in children with CP is key for individualized prescription and assessment of muscle-targeted interventions. Findings could imply the detection of children operating on the descending limb of the sarcomere length-tension curve, which in turn might be at greater risk of developing crouch gait. Furthermore, relative muscle fascicle excursions could be used as a predictive variable of outcomes related to crouch gait prevention treatments such as strength training. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Electricity by intermittent sources: An analysis based on the German situation 2012

    NASA Astrophysics Data System (ADS)

    Wagner, Friedrich

    2014-02-01

    The 2012 data of the German load, the on- and offshore and the photo-voltaic energy production are used and scaled to the limit of supplying the annual demand (100% case). The reference mix of the renewable energy (RE) forms is selected such that the remaining back-up energy is minimised. For the 100% case, the RE power installation has to be about 3 times the present peak load. The back-up system can be reduced by 12% in this case. The surplus energy corresponds to 26% of the demand. The back-up system and more so the grid must be able to cope with large power excursions. All components of the electricity supply system operate at low capacity factors. Large-scale storage can hardly be motivated by the effort to further reduce CO2 emission. Demand-side management will intensify the present periods of high economic activities. Its rigorous implementation will expand the economic activities into the weekends. On the basis of a simple criterion, the increase of periods with negative electricity prices in Germany is assessed. It will be difficult with RE to meet the low CO2 emission factors which characterise those European Countries which produce electricity mostly by nuclear and hydro power.

  12. A Whale of an Interest in Sea Creatures: The Learning Potential of Excursions

    ERIC Educational Resources Information Center

    Hedges, Helen

    2004-01-01

    Excursions, or field trips, are a common component of early childhood programs, seen as a means of enriching the curriculum by providing experiences with people, places, and things in the community. Although excursions have been used as a framework for research on children's memory development, research on the efficacy of excursions in terms of…

  13. Value of self-monitoring blood glucose pattern analysis in improving diabetes outcomes.

    PubMed

    Parkin, Christopher G; Davidson, Jaime A

    2009-05-01

    Self-monitoring of blood glucose (SMBG) is an important adjunct to hemoglobin A1c (HbA1c) testing. This action can distinguish between fasting, preprandial, and postprandial hyperglycemia; detect glycemic excursions; identify and monitor resolution of hypoglycemia; and provide immediate feedback to patients about the effect of food choices, activity, and medication on glycemic control. Pattern analysis is a systematic approach to identifying glycemic patterns within SMBG data and then taking appropriate action based upon those results. The use of pattern analysis involves: (1) establishing pre- and postprandial glucose targets; (2) obtaining data on glucose levels, carbohydrate intake, medication administration (type, dosages, timing), activity levels and physical/emotional stress; (3) analyzing data to identify patterns of glycemic excursions, assessing any influential factors, and implementing appropriate action(s); and (4) performing ongoing SMBG to assess the impact of any therapeutic changes made. Computer-based and paper-based data collection and management tools can be developed to perform pattern analysis for identifying patterns in SMBG data. This approach to interpreting SMBG data facilitates rational therapeutic adjustments in response to this information. Pattern analysis of SMBG data can be of equal or greater value than measurement of HbA1c levels. 2009 Diabetes Technology Society.

  14. Nuclear reactor safety device

    DOEpatents

    Hutter, Ernest

    1986-01-01

    A safety device is disclosed for use in a nuclear reactor for axially repositioning a control rod with respect to the reactor core in the event of an upward thermal excursion. Such safety device comprises a laminated helical ribbon configured as a tube-like helical coil having contiguous helical turns with slidably abutting edges. The helical coil is disclosed as a portion of a drive member connected axially to the control rod. The laminated ribbon is formed of outer and inner laminae. The material of the outer lamina has a greater thermal coefficient of expansion than the material of the inner lamina. In the event of an upward thermal excursion, the laminated helical coil curls inwardly to a smaller diameter. Such inward curling causes the total length of the helical coil to increase by a substantial increment, so that the control rod is axially repositioned by a corresponding amount to reduce the power output of the reactor.

  15. Intermittent Fermi-Pasta-Ulam Dynamics at Equilibrium

    NASA Astrophysics Data System (ADS)

    Campbell, David; Danieli, Carlo; Flach, Sergej

    The equilibrium value of an observable defines a manifold in the phase space of an ergodic and equipartitioned many-body syste. A typical trajectory pierces that manifold infinitely often as time goes to infinity. We use these piercings to measure both the relaxation time of the lowest frequency eigenmode of the Fermi-Pasta-Ulam chain, as well as the fluctuations of the subsequent dynamics in equilibrium. We show that previously obtained scaling laws for equipartition times are modified at low energy density due to an unexpected slowing down of the relaxation. The dynamics in equilibrium is characterized by a power-law distribution of excursion times far off equilibrium, with diverging variance. The long excursions arise from sticky dynamics close to regular orbits in the phase space. Our method is generalizable to large classes of many-body systems. The authors acknowledge financial support from IBS (Project Code IBS-R024-D1).

  16. Self-compression of spatially limited laser pulses in a system of coupled light-guides

    NASA Astrophysics Data System (ADS)

    Balakin, A. A.; Litvak, A. G.; Mironov, V. A.; Skobelev, S. A.

    2018-04-01

    The self-action features of wave packets propagating in a 2D system of equidistantly arranged fibers are studied analytically and numerically on the basis of the discrete nonlinear Schrödinger equation. Self-consistent equations for the characteristic scales of a Gaussian wave packet are derived on the basis of the variational approach, which are proved numerically for powers P < 10 P_cr , slightly exceeding the critical one for self-focusing. At higher powers, the wave beams become filamented, and their amplitude is limited due to the nonlinear breaking of the interaction between neighboring light-guides. This makes it impossible to collect a powerful wave beam in a single light-guide. Variational analysis shows the possibility of the adiabatic self-compression of soliton-like laser pulses in the process of 3D self-focusing on the central light-guide. However, further increase of the field amplitude during self-compression leads to the development of longitudinal modulation instability and the formation of a set of light bullets in the central fiber. In the regime of hollow wave beams, filamentation instability becomes predominant. As a result, it becomes possible to form a set of light bullets in optical fibers located on the ring.

  17. Evaluation of pediatric ATD biofidelity as compared to child volunteers in low-speed far-side oblique and lateral impacts.

    PubMed

    Seacrist, Thomas; Locey, Caitlin M; Mathews, Emily A; Jones, Dakota L; Balasubramanian, Sriram; Maltese, Matthew R; Arbogast, Kristy B

    2014-01-01

    Motor vehicle crashes are a leading cause of injury and mortality for children. Mitigation of these injuries requires biofidelic anthropomorphic test devices (ATDs) to design and evaluate automotive safety systems. Effective countermeasures exist for frontal and near-side impacts but are limited for far-side impacts. Consequently, far-side impacts represent increased injury and mortality rates compared to frontal impacts. Thus, the objective of this study was to evaluate the biofidelity of the Hybrid III and Q-series pediatric ATDs in low-speed far-side impacts, with and without shoulder belt pretightening. Low-speed (2 g) far-side oblique (60°) and lateral (90°) sled tests were conducted using the Hybrid III and Q-series 6- and 10-year-old ATDs. ATDs were restrained by a lap and shoulder belt equipped with a precrash belt pretightener. Photoreflective targets were attached to the head, spine, shoulders, and sternum. ATDs were exposed to 8 low-speed sled tests: 2 oblique nontightened, 2 oblique pretightened, 2 lateral nontightened, 2 lateral pretightened. ATDs were compared with previously collected 9- to 11-year-old (n=10) volunteer data and newly collected 6- to 8-year-old volunteer data (n=7) tested with similar methods. Kinematic data were collected from a 3D target tracking system. Metrics of comparison included excursion, seat belt and seat pan reaction loads, belt-to-torso angle, and shoulder belt slip-out. The ATDs exhibited increased lateral excursion of the head top, C4, and T1 as well as increased downward excursion of the head top compared to the volunteers. Volunteers exhibited greater forward excursion than the ATDs in oblique nontightened impacts. These kinematics correspond to increased shoulder belt slip-out for the ATDs in oblique tests (ATDs=90%; volunteers=36%). Contrarily, similar shoulder belt slip-out was observed between ATDs and volunteers in lateral impacts (ATDs=80%; volunteers=78%). In pretightened impacts, the ATDs exhibited reduced lateral excursion and torso roll-out angle compared to the volunteers. In general, the ATDs overestimated lateral excursion in both impact directions, while underestimating forward excursion of the head and neck in oblique impacts compared to the pediatric volunteers. This was primarily due to pendulum-like lateral bending of the entire ATD torso compared to translation of the thorax relative to the abdomen prior to the lateral bending of the upper torso in the volunteers, likely due to the multisegmented spinal column in the volunteers. Additionally, the effect of belt pretightening on occupant kinematics was greater for the ATDs than the volunteers.

  18. Altered Tibiofemoral Joint Contact Mechanics and Kinematics in Patients with Knee Osteoarthritis and Episodic Complaints of Joint Instability

    PubMed Central

    Farrokhi, Shawn; Voycheck, Carrie A.; Klatt, Brian A.; Gustafson, Jonathan A.; Tashman, Scott; Fitzgerald, G. Kelley

    2014-01-01

    Background To evaluate knee joint contact mechanics and kinematics during the loading response phase of downhill gait in knee osteoarthritis patients with self-reported instability. Methods Forty-three subjects, 11 with medial compartment knee osteoarthritis and self-reported instability (unstable), 7 with medial compartment knee osteoarthritis but no reports of instability (stable), and 25 without knee osteoarthritis or instability (control) underwent Dynamic Stereo X-ray analysis during a downhill gait task on a treadmill. Findings The medial compartment contact point excursions were longer in the unstable group compared to the stable (p=0.046) and the control groups (p=0.016). The peak medial compartment contact point velocity was also greater for the unstable group compared to the stable (p=0.047) and control groups (p=0.022). Additionally, the unstable group demonstrated a coupled movement pattern of knee extension and external rotation after heel contact which was different than the coupled motion of knee flexion and internal rotation demonstrated by stable and control groups. Interpretation Our findings suggest that knee joint contact mechanics and kinematics are altered during the loading response phase of downhill gait in knee osteoarthritis patients with self-reported instability. The observed longer medial compartment contact point excursions and higher velocities represent objective signs of mechanical instability that may place the arthritic knee joint at increased risk for disease progression. Further research is indicated to explore the clinical relevance of altered contact mechanics and kinematics during other common daily activities and to assess the efficacy of rehabilitation programs to improve altered joint biomechanics in knee osteoarthritis patients with self-reported instability. PMID:24856791

  19. Relationship of the functional movement screen in-line lunge to power, speed, and balance measures.

    PubMed

    Hartigan, Erin H; Lawrence, Michael; Bisson, Brian M; Torgerson, Erik; Knight, Ryan C

    2014-05-01

    The in-line lunge of the Functional Movement Screen (FMS) evaluates lateral stability, balance, and movement asymmetries. Athletes who score poorly on the in-line lunge should avoid activities requiring power or speed until scores are improved, yet relationships between the in-line lunge scores and other measures of balance, power, and speed are unknown. (1) Lunge scores will correlate with center of pressure (COP), maximum jump height (MJH), and 36.6-meter sprint time and (2) there will be no differences between limbs on lunge scores, MJH, or COP. Descriptive laboratory study. Level 3. Thirty-seven healthy, active participants completed the first 3 tasks of the FMS (eg, deep squat, hurdle step, in-line lunge), unilateral drop jumps, and 36.6-meter sprints. A 3-dimensional motion analysis system captured MJH. Force platforms measured COP excursion. A laser timing system measured 36.6-m sprint time. Statistical analyses were used to determine whether a relationship existed between lunge scores and COP, MJH, and 36.6-m speed (Spearman rho tests) and whether differences existed between limbs in lunge scores (Wilcoxon signed-rank test), MJH, and COP (paired t tests). Lunge scores were not significantly correlated with COP, MJH, or 36.6-m sprint time. Lunge scores, COP excursion, and MJH were not statistically different between limbs. Performance on the FMS in-line lunge was not related to balance, power, or speed. Healthy participants were symmetrical in lunging measures and MJH. Scores on the FMS in-line lunge should not be attributed to power, speed, or balance performance without further examination. However, assessing limb symmetry appears to be clinically relevant.

  20. The effect of muscle excursion on muscle recovery after tendon repair in a neglected tendon injury: a study in rabbit soleus muscles.

    PubMed

    Jeon, Suk Ha; Chung, Moon Sang; Baek, Goo Hyun; Lee, Young Ho; Gong, Hyun Sik

    2011-01-01

    We attempted to determine whether muscle excursion observed during operation can be a prognostic indicator of muscle recovery after delayed tendon repair in a rabbit soleus model. Eighteen rabbits underwent tenotomy of the soleus muscles bilaterally and were divided into three groups according to the period from tenotomy to repair. The tendons of each group were repaired 2, 4, and 6 weeks after tenotomy. The excursion of each soleus muscle was measured at the time of tenotomy (baseline), at 2, 4, 6 weeks after tenotomy, and 8 weeks after tendon repair. The amount of muscle recovery after tendon repair in terms of muscle excursion independently depended on the timing of repair and on the muscle excursion observed during repair. The regression model predicted that the muscle excursion recovered on average by 0.6% as the muscle excursion at the time of repair increased by 1% after adjusting for the timing of repair. This study suggests that measuring the muscle excursion during tendon repair may help physicians estimate the potential of muscle recovery in cases of delayed tendon repair. Copyright © 2010 Orthopaedic Research Society.

  1. Coupled high-resolution marine and terrestrial records of carbon and hydrologic cycles variations during the Paleocene-Eocene Thermal Maximum (PETM)

    NASA Astrophysics Data System (ADS)

    Tipple, Brett J.; Pagani, Mark; Krishnan, Srinath; Dirghangi, Sitindra S.; Galeotti, Simone; Agnini, Claudia; Giusberti, Luca; Rio, Domenico

    2011-11-01

    The Paleocene-Eocene Thermal Maximum is characterized by a massive perturbation of the global carbon cycle reflected in a large, negative carbon isotope excursion associated with rapid global warming and changes in the hydrologic system. The magnitude of the carbon isotope excursion from terrestrial carbonates and organic carbon is generally larger relative to marine carbonates. However, high-resolution marine and terrestrial isotopic records from the same locality for direct comparison are limited. Here we present coupled carbon isotope records from terrestrial biomarkers (δ 13C n-alkane ), marine bulk carbonates (δ 13C carbonate), and bulk organic carbon (δ 13C organic) from the continuous sedimentary record of the Forada section in northern Italy in order to evaluate the magnitude and phase relationships between terrestrial and marine environments. Consistent with previous reports, we find that the carbon isotope excursion established from δ 13C n-alkane values is more negative than those established from δ 13C carbonate and δ 13C organic values. In contrast to the majority of PETM records, all Forada δ 13C records show a sharp 13C-enrichment immediately following the onset of the carbon isotope excursion. Further, the terrestrial δ 13C n-alkane record lags δ 13C carbonate/δ 13C organic trends by ~ 4-5 kyr—offsets that reflect the long residence time of soil organic carbon. Hydrogen isotope records from higher-plant leaf waxes (δD n-alkane ) and sea-surface temperatures (TEX 86) were established to assess hydrologic and ocean temperature trends. We find δD n-alkane values trend more positive, associated with higher temperatures prior to the onset of the carbon isotope excursion, and conclude that regional changes in the hydrologic cycle likely occurred before the onset of the carbon isotope anomaly.

  2. ePave: A Self-Powered Wireless Sensor for Smart and Autonomous Pavement.

    PubMed

    Xiao, Jian; Zou, Xiang; Xu, Wenyao

    2017-09-26

    "Smart Pavement" is an emerging infrastructure for various on-road applications in transportation and road engineering. However, existing road monitoring solutions demand a certain periodic maintenance effort due to battery life limits in the sensor systems. To this end, we present an end-to-end self-powered wireless sensor-ePave-to facilitate smart and autonomous pavements. The ePave system includes a self-power module, an ultra-low-power sensor system, a wireless transmission module and a built-in power management module. First, we performed an empirical study to characterize the piezoelectric module in order to optimize energy-harvesting efficiency. Second, we developed an integrated sensor system with the optimized energy harvester. An adaptive power knob is designated to adjust the power consumption according to energy budgeting. Finally, we intensively evaluated the ePave system in real-world applications to examine the system's performance and explore the trade-off.

  3. ePave: A Self-Powered Wireless Sensor for Smart and Autonomous Pavement

    PubMed Central

    Xiao, Jian; Zou, Xiang

    2017-01-01

    “Smart Pavement” is an emerging infrastructure for various on-road applications in transportation and road engineering. However, existing road monitoring solutions demand a certain periodic maintenance effort due to battery life limits in the sensor systems. To this end, we present an end-to-end self-powered wireless sensor—ePave—to facilitate smart and autonomous pavements. The ePave system includes a self-power module, an ultra-low-power sensor system, a wireless transmission module and a built-in power management module. First, we performed an empirical study to characterize the piezoelectric module in order to optimize energy-harvesting efficiency. Second, we developed an integrated sensor system with the optimized energy harvester. An adaptive power knob is designated to adjust the power consumption according to energy budgeting. Finally, we intensively evaluated the ePave system in real-world applications to examine the system’s performance and explore the trade-off. PMID:28954430

  4. Transients control in Raman fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Freitas, Marcio; Givigi, Sidney N., Jr.; Klein, Jackson; Calmon, Luiz C.; de Almeida, Ailson R.

    2004-11-01

    Raman fiber amplifiers (RFA) are being used in optical transmission communication systems in the recent years due to their advantages in comparison to erbium-doped fiber amplifiers (EDFA). Recently the analysis of RFAs dynamic response and transients control has become important in order to predict the system response to add/drop of channels or cable cuts in optical systems, and avoid impairments caused by the power transients. Fast signal power transients in the surviving channels are caused by the cross-gain saturation effect in RFA and the slope of the gain saturation characteristics determines the steady-state surviving channel power excursion. We are presenting the modeling and analysis of power transients and its control using a pump control method for a single and multi-pump scheme.

  5. Mercury enrichment indicates volcanic triggering of Valanginian environmental change

    PubMed Central

    Charbonnier, Guillaume; Morales, Chloé; Duchamp-Alphonse, Stéphanie; Westermann, Stéphane; Adatte, Thierry; Föllmi, Karl B.

    2017-01-01

    The Valanginian stage (Early Cretaceous) includes an episode of significant environmental changes, which are well defined by a positive δ13C excursion. This globally recorded excursion indicates important perturbations in the carbon cycle, which has tentatively been associated with a pulse in volcanic activity and the formation of the Paraná-Etendeka large igneous province (LIP). Uncertainties in existing age models preclude, however, its positive identification as a trigger of Valanginian environmental changes. Here we report that in Valanginian sediments recovered from a drill core in Wąwał (Polish Basin, Poland), and from outcrops in the Breggia Gorge (Lombardian Basin, southern Switzerland), and Orpierre and Angles (Vocontian Basin, SE France), intervals at or near the onset of the positive δ13C excursion are significantly enriched in mercury (Hg). The persistence of the Hg anomaly in Hg/TOC, Hg/phyllosilicate, and Hg/Fe ratios shows that organic-matter scavenging and/or adsorbtion onto clay minerals or hydrous iron oxides only played a limited role. Volcanic outgassing was most probably the primary source of the Hg enrichments, which demonstrate that an important magmatic pulse triggered the Valanginian environmental perturbations. PMID:28106091

  6. Fueled By Wealth, Funneled By Politics: The Dominance of Domestic Drivers of Arms Procurement in Southeast Asia

    DTIC Science & Technology

    2015-12-01

    in driving arms procurements in Malaysia , Indonesia, and Singapore: availability of resources, domestic politics, external threats, and force...could incite more frequent excursions toward competitive arms dynamics. 14. SUBJECT TERMS Malaysia , Indonesia, Singapore, Southeast Asia, arms...This thesis investigates the following four factors to determine which are most powerful in driving arms procurements in Malaysia , Indonesia, and

  7. 29 CFR 1910.1001 - Asbestos.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... The designation of a material as “PACM” may be rebutted pursuant to paragraph (j)(8) of this section... level as demonstrated by a statistically valid protocol; and (C) The equivalent method is documented and... PACM are in excess of the TWA and/or excursion limit prescribed in paragraph (c) of this section. (2...

  8. 29 CFR 1910.1001 - Asbestos.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... The designation of a material as “PACM” may be rebutted pursuant to paragraph (j)(8) of this section... level as demonstrated by a statistically valid protocol; and (C) The equivalent method is documented and... PACM are in excess of the TWA and/or excursion limit prescribed in paragraph (c) of this section. (2...

  9. Beyond the Lonely, Choosing Will: Professional Development in Teacher Thinking. Occasional Paper No. 131.

    ERIC Educational Resources Information Center

    Buchmann, Margret

    This paper aims to accomplish several purposes through conceptual analysis, story telling and interpretation, excursions into philosophy, and recent studies of teachers' professional development. First, the paper identifies limitations and confusions in current conceptions of teachers' professional thinking: equating teacher thinking with planning…

  10. The effect of spinal position on sciatic nerve excursion during seated neural mobilisation exercises: an in vivo study using ultrasound imaging

    PubMed Central

    Ellis, Richard; Osborne, Samantha; Whitfield, Janessa; Parmar, Priya; Hing, Wayne

    2017-01-01

    Objectives Research has established that the amount of inherent tension a peripheral nerve tract is exposed to influences nerve excursion and joint range of movement (ROM). The effect that spinal posture has on sciatic nerve excursion during neural mobilisation exercises has yet to be determined. The purpose of this research was to examine the influence of different sitting positions (slump-sitting versus upright-sitting) on the amount of longitudinal sciatic nerve movement during different neural mobilisation exercises commonly used in clinical practice. Methods High-resolution ultrasound imaging followed by frame-by-frame cross-correlation analysis was used to assess sciatic nerve excursion. Thirty-four healthy participants each performed three different neural mobilisation exercises in slump-sitting and upright-sitting. Means comparisons were used to examine the influence of sitting position on sciatic nerve excursion for the three mobilisation exercises. Linear regression analysis was used to determine whether any of the demographic data represented predictive variables for longitudinal sciatic nerve excursion. Results There was no significant difference in sciatic nerve excursion (across all neural mobilisation exercises) observed between upright-sitting and slump-sitting positions (P = 0.26). Although greater body mass index, greater knee ROM and younger age were associated with higher levels of sciatic nerve excursion, this model of variables offered weak predictability (R2 = 0.22). Discussion Following this study, there is no evidence that, in healthy people, longitudinal sciatic nerve excursion differs significantly with regards to the spinal posture (slump-sitting and upright-sitting). Furthermore, although some demographic variables are weak predictors, the high variance suggests that there are other unknown variables that may predict sciatic nerve excursion. It can be inferred from this research that clinicians can individualise the design of seated neural mobilisation exercises, using different seated positions, based upon patient comfort and minimisation of neural mechanosensitivity with the knowledge that sciatic nerve excursion will not be significantly influenced. PMID:28559669

  11. Conducting polymer electrodes for visual prostheses.

    PubMed

    Green, R A; Devillaine, F; Dodds, C; Matteucci, P; Chen, S; Byrnes-Preston, P; Poole-Warren, L A; Lovell, N H; Suaning, G J

    2010-01-01

    Conducting polymers (CPs) have the potential to provide superior neural interfaces to conventional metal electrodes by introducing more efficient charge transfer across the same geometric area. In this study the conducting polymer poly(ethylene dioxythiophene) (PEDOT) was coated on platinum (Pt) microelectrode arrays. The in vitro electrical characteristics were assessed during biphasic stimulation regimes applied between electrode pairs. It was demonstrated that PEDOT could reduce the potential excursion at a Pt electrode interface by an order of magnitude. The charge injection limit of PEDOT was found to be 15 x larger than Pt. Additionally, PEDOT coated electrodes were acutely implanted in the suprachoroidal space of a cat retina. It was demonstrated that PEDOT coated electrodes also had lower potential excursions in vivo and electrically evoked potentials (EEPs) could be detected within the vision cortex.

  12. Self-mode-locked chromium-doped forsterite laser generates 50-fs pulses

    NASA Technical Reports Server (NTRS)

    Seas, A.; Petricevic, V.; Alfano, R. R.

    1993-01-01

    Stable transform-limited (delta nu-delta tau = 0.32) femtosecond pulses with a FWHM of 50 fs were generated from a self-mode-locked chromium-doped forsterite laser. The forsterite laser was synchronously pumped by a CW mode-locked Nd:YAG (82 MHz) laser that generated picosecond pulses (200-300 ps) and provided the starting mechanism for self-mode-locked operation. Maximum output power was 45 mW for 3.9 W of absorbed pumped power with the use of an output coupler with 1 percent transmission. The self-mode-locked forsterite laser was tuned from 1240 to 1270 nm.

  13. Evaluation of diaphragmatic motion in normal and diaphragmatic paralyzed dogs using M-mode ultrasonography.

    PubMed

    Choi, Mihyun; Lee, Namsoon; Kim, Ahyoung; Keh, Seoyeon; Lee, Jinsoo; Kim, Hyunwook; Choi, Mincheol

    2014-01-01

    Diagnosis of unilateral diaphragmatic paralysis in dogs is currently based on fluoroscopic detection of unequal movement between the crura. Bilateral paralysis may be more difficult to confirm with fluoroscopy because diaphragmatic movement is sometimes produced by compensatory abdominal muscle contractions. The purpose of this study was to develop a new method to evaluate diaphragmatic movement using M-mode ultrasonography and to describe findings for normal and diaphragmatic paralyzed dogs. Fifty-five clinically normal dogs and two dogs with diaphragmatic paralysis were recruited. Thoracic radiographs were acquired for all dogs and fluoroscopy studies were also acquired for clinically affected dogs. Two observers independently measured diaphragmatic direction of motion and amplitude of excursion using M-mode ultrasonography for dogs meeting study inclusion criteria. Eight of the clinically normal dogs were excluded due to abnormal thoracic radiographic findings. For the remaining normal dogs, the lower limit values of diaphragmatic excursion were 2.85-2.98 mm during normal breathing. One dog with bilateral diaphragmatic paralysis showed paradoxical movement of both crura at the end of inspiration. One dog with unilateral diaphragmatic paralysis had diaphragmatic excursion values of 2.00 ± 0.42 mm on the left side and 4.05 ± 1.48 mm on the right side. The difference between left and right diaphragmatic excursion values was 55%. Findings indicated that M-mode ultrasonography is a relatively simple and objective method for measuring diaphragmatic movement in dogs. Future studies are needed in a larger number of dogs with diaphragmatic paralysis to determine the diagnostic sensitivity of this promising new technique. © 2013 American College of Veterinary Radiology.

  14. Review of droop-controlled bi-directional inverter in conducting islanded operation of photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Khaw, Ace Lin Yi; Wong, Jianhui; Lim, Yun Seng

    2017-04-01

    Global warming due to the excessive greenhouse gas emissions has led to the emergence of green technologies in Malaysia, particularly photovoltaic (PV) systems. Under the current regulatory framework, islanded operation of the PV system is not permissible. As a result, any renewable energy sources will be disconnected immediately in the event of grid outages. This practice is to ensure the safety of working personnel, as well as the customer equipment connected within the distribution networks. In addition, there is no synchronizing equipment to aid the reconnection of the islanded network to the grid. However, with the shutdown of the Distributed Generator (DG) during islanded operation, the customers are not able to utilize the available renewable energy and the number of power interruption is not improved with the renewable energy sources. Therefore, the main objective of this paper is to investigate the feasibility of the PV system in conducting islanding operation with the use of Energy Storage System (ESS). This paper also proposes a control algorithm to maintain the voltage and frequency excursion within the statutory limit by manipulating the real and reactive power flow of the ESS within the transition period between grid connected and islanding operation.

  15. Three-dimensional kinematics of the lower limbs during forward ice hockey skating.

    PubMed

    Upjohn, Tegan; Turcotte, René; Pearsall, David J; Loh, Jonathan

    2008-05-01

    The objectives of the study were to describe lower limb kinematics in three dimensions during the forward skating stride in hockey players and to contrast skating techniques between low- and high-calibre skaters. Participant motions were recorded with four synchronized digital video cameras while wearing reflective marker triads on the thighs, shanks, and skates. Participants skated on a specialized treadmill with a polyethylene slat bed at a self-selected speed for 1 min. Each participant completed three 1-min skating trials separated by 5 min of rest. Joint and limb segment angles were calculated within the local (anatomical) and global reference planes. Similar gross movement patterns and stride rates were observed; however, high-calibre participants showed a greater range and rate of joint motion in both the sagittal and frontal planes, contributing to greater stride length for high-calibre players. Furthermore, consequent postural differences led to greater lateral excursion during the power stroke in high-calibre skaters. In conclusion, specific kinematic differences in both joint and limb segment angle movement patterns were observed between low- and high-calibre skaters.

  16. Operating characteristics of a 0.87 kW-hr flywheel energy storage module

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Scibbe, H. W.; Parker, R. D.; Zaretsky, E. V.

    1985-01-01

    Discussion is given of the design and loss characteristics of 0.87 kW-hr (peak) flywheel energy storage module suitable for aerospace and automotive applications. The maraging steel flywheel rotor, a 46-cm- (18-in-) diameter, 58-kg (128-lb) tapered disk, delivers 0.65 kW-hr of usable energy between operating speeds of 10,000 and 20,000 rpm. The rotor is supported by 20- and 25-mm bore diameter, deep-groove ball bearings, lubricated by a self-replenishing wick type lubrication system. To reduce aerodynamic losses, the rotor housing was evacuated to vacuum levels from 40 to 200 millitorr. Dynamic rotor instabilities uncovered during testing necessitated the use of an elastometric-bearing damper to limit shaft excursions. Spindown losses from bearing, seal, and aerodynamic drag at 50 millitorr typically ranged from 64 to 193 W at 10,000 and 20,000 rpm, respectively. Discharge efficiency of the flywheel system exceeded 96 percent at torque levels greater than 21 percent of rated torque.

  17. Comparison of standard (self-directed) versus intensive patient training for the human insulin inhalation powder (HIIP) delivery system in patients with type 2 diabetes: efficacy, safety, and training measures.

    PubMed

    Rosenstock, Julio; Nakano, Masako; Silverman, Bernard L; Sun, Bin; de la Peña, Amparo; Suri, Ajit; Muchmore, Douglas B

    2007-02-01

    The Lilly/Alkermes human insulin inhalation powder (HIIP) delivery system [AIR (a registered trademark of Alkermes, Inc., Cambridge, MA) Inhaled Insulin System] was designed to be easy to use. Training methods were compared in insulin-naive patients with type 2 diabetes. Patients (n = 102) were randomized to standard or intensive training. With standard training, patients learned how to use the HIIP delivery system by reading directions for use (DFU) and trying on their own. Intensive training included orientation to the HIIP delivery system with individual coaching and inspiratory flow rate training. Both groups received preprandial HIIP + metformin with or without a thiazolidinedione for 4 weeks. Overall 2-h postprandial blood glucose (PPBG) excursion was the primary measure. Noninferiority was defined as the upper limit of the two-sided 95% confidence interval of the mean difference between groups being 1.2 < or = mmol/L. Overall 2-h PPBG excursions (least squares mean +/- SE) at endpoint were -0.11 +/- 0.38 (standard training) and 0.23 +/- 0.36 (intensive training) mmol/L. The mean difference (standard minus intensive training) and two-sided 95% confidence interval were -0.35 (-1.02, 0.33) mmol/L. No statistically or clinically significant differences were observed between training methods in premeal, postmeal, or bedtime blood glucose values, HIIP doses at endpoint, or blood glucose values after a test meal. No discontinuations occurred because of difficulty of use or dislike of the HIIP system. DFU compliance was >90% in both training groups. There were no significant differences between training methods in safety measures. The HIIP delivery system is easy to use, and most patients can learn to use it by reading the DFU without assistance from health care professionals.

  18. Enzymatic biofuel cell-based self-powered biosensing of protein kinase activity and inhibition via thiophosphorylation-mediated interface engineering.

    PubMed

    Gu, Chengcheng; Gai, Panpan; Han, Lei; Yu, Wen; Liu, Qingyun; Li, Feng

    2018-05-24

    We developed a facile and ultrasensitive enzymatic biofuel cell (EBFC)-based self-powered biosensor of protein kinase A (PKA) activity and inhibition via thiophosphorylation-mediated interface engineering. The detection limit was down to 0.00022 U mL-1 (S/N = 3). In addition, the PKA activities from MCF-7 and A549 cell lysates were analyzed and achieved reliable results.

  19. Thermal anomalies of the transmitter experiment package on the communications technology satellite

    NASA Technical Reports Server (NTRS)

    Alexovich, R. E.; Curren, A. N.

    1979-01-01

    The causes of four temporary thermal-control-system malfunctions that gave rise to unexpected temperature excursions in the 12-gigahertz, 200-watt transmitter experiment package (TEP) on the Communications Technology Satellite were investigated. The TEP consists of a nominal 200-watt output stage tube (OST), a supporting power-processing system (PPS), and a variable-conductance heat-pipe system (VCHPS). The VCHPS, which uses three heat pipes to conduct heat from the body of the OST to a radiator fin, was designed to maintain the TEP at safe operating temperatures at all operating conditions. On four occasions during 1977, all near the spring and fall equinoxes, the OST body temperature and related temperatures displayed sudden, rapid, and unexpected rises above normal levels while the TEP was operating at essentially constant, normal conditions. The temperature excursions were terminated without TEP damage by reducing the radio frequency (RF) output power of the OST. Between the anomalies and since the fourth, the thermal control system has apparently functioned as designed. The results indicate the most probable cause of the temperature anomalies is depriming of the arteries in the variable-conductance heat pipes. A mode was identified in which the TEP, as presently configured, may operate with stable temperatures and with minimum change in performance level.

  20. Geometry and scaling laws of excursion and iso-sets of enstrophy and dissipation in isotropic turbulence

    NASA Astrophysics Data System (ADS)

    Elsas, José Hugo; Szalay, Alexander S.; Meneveau, Charles

    2018-04-01

    Motivated by interest in the geometry of high intensity events of turbulent flows, we examine the spatial correlation functions of sets where turbulent events are particularly intense. These sets are defined using indicator functions on excursion and iso-value sets. Their geometric scaling properties are analysed by examining possible power-law decay of their radial correlation function. We apply the analysis to enstrophy, dissipation and velocity gradient invariants Q and R and their joint spatial distributions, using data from a direct numerical simulation of isotropic turbulence at Reλ ≈ 430. While no fractal scaling is found in the inertial range using box-counting in the finite Reynolds number flow considered here, power-law scaling in the inertial range is found in the radial correlation functions. Thus, a geometric characterisation in terms of these sets' correlation dimension is possible. Strong dependence on the enstrophy and dissipation threshold is found, consistent with multifractal behaviour. Nevertheless, the lack of scaling of the box-counting analysis precludes direct quantitative comparisons with earlier work based on multifractal formalism. Surprising trends, such as a lower correlation dimension for strong dissipation events compared to strong enstrophy events, are observed and interpreted in terms of spatial coherence of vortices in the flow.

  1. Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals.

    PubMed

    LaMontagne, A D; Kelsey, K T

    2001-03-01

    This study sought to identify determinants of workplace exposures to ethylene oxide to assess the effect of the Occupational Safety and Health Administration's (OSHA's) 1984 ethylene oxide standard. An in-depth survey of all hospitals in Massachusetts that used ethylene oxide from 1990 through 1992 (96% participation, N = 90) was conducted. Three types of exposure events were modeled with logistic regression: exceeding the 8-hour action level, exceeding the 15-minute excursion limit, and worker exposures during unmeasured accidental releases. Covariates were drawn from data representing an ecologic framework including direct and indirect potential exposure determinants. After adjustment for frequencies of ethylene oxide use and exposure monitoring, a significant inverse relation was observed between exceeding the action level and the use of combined sterilizer-aerators, an engineering control technology developed after the passage of the OSHA standard. Conversely, the use of positive-pressure sterilizers that employ ethylene oxide gas mixtures was strongly related to both exceeding the excursion limit and the occurrence of accidental releases. These findings provide evidence of a positive effect of OSHA's ethylene oxide standard and specific targets for future prevention and control efforts.

  2. 30W, 10μJ, 10-ps SPM-induced spectrally compressed pulse generation in a low non-linearity ytterbium-doped rod-type fibre amplifier

    NASA Astrophysics Data System (ADS)

    Zaouter, Y.; Cormier, E.; Rigail, P.; Hönninger, C.; Mottay, E.

    2007-02-01

    The concept of spectral compression induced by self phase modulation is used to generate transform-limited 10ps pulses in a rare-earth-doped low nonlinearity fibre amplifier. The seed source of the amplifier stage is a high power, Yb 3+:KGW bulk oscillator which delivers 500 fs transform-limited pulses at 10MHz repetition rate. After a reduction of the repetition rate down to 3MHz, the femtosecond pulses are negatively chirped by transmission gratings in a compressor arrangement. The resulting 10ps pulses are further seeded into the power amplifier and up to 32W output power is obtained while the spectral bandwidth is reduced to less than 0.5 nm by means of self phase modulation.

  3. Effect of the self-pumped limiter concept on the tritium fuel cycle

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

    Finn, P.A.; Sze, D.K.; Hassanein, A.

    1988-09-01

    The self-pumped limiter concept was the impurity control system for the reactor in the Tokamak Power Systems Study (TPSS). The use of a self-pumped limiter had a major impact on the design of the tritium systems of the TPSS fusion reactor. The self-pumped limiter functions by depositing the helium ash under a layer of metal (vanadium). The majority of the hydrogen species are recycled at the plasma edge; a small fraction permeates to the blanket/coolant which was lithium in TPSS. Use of the self-pumped limiter results in the elimination of the plasma processing system. Thus, the blanket tritium processing systemmore » becomes the major tritium system. The main advantages achieved for the tritium systems with a self-pumped limiter are a reduction in the capital cost of tritium processing equipment as well as a reduction in building space, a reduced tritium inventory for processing and for reserve storage, an increase in the inherent safety of the fusion plant and an improvement in economics for a fusion world economy.« less

  4. Autonomous self-powered structural health monitoring system

    NASA Astrophysics Data System (ADS)

    Qing, Xinlin P.; Anton, Steven R.; Zhang, David; Kumar, Amrita; Inman, Daniel J.; Ooi, Teng K.

    2010-03-01

    Structural health monitoring technology is perceived as a revolutionary method of determining the integrity of structures involving the use of multidisciplinary fields including sensors, materials, system integration, signal processing and interpretation. The core of the technology is the development of self-sufficient systems for the continuous monitoring, inspection and damage detection of structures with minimal labor involvement. A major drawback of the existing technology for real-time structural health monitoring is the requirement for external electrical power input. For some applications, such as missiles or combat vehicles in the field, this factor can drastically limit the use of the technology. Having an on-board electrical power source that is independent of the vehicle power system can greatly enhance the SHM system and make it a completely self-contained system. In this paper, using the SMART layer technology as a basis, an Autonomous Self-powered (ASP) Structural Health Monitoring (SHM) system has been developed to solve the major challenge facing the transition of SHM systems into field applications. The architecture of the self-powered SHM system was first designed. There are four major components included in the SHM system: SMART Layer with sensor network, low power consumption diagnostic hardware, rechargeable battery with energy harvesting device, and host computer with supporting software. A prototype of the integrated self-powered active SHM system was built for performance and functionality testing. Results from the evaluation tests demonstrated that a fully charged battery system is capable of powering the SHM system for active scanning up to 10 hours.

  5. Autonomous excursions using tablets and smartphones

    NASA Astrophysics Data System (ADS)

    Marra, Wouter; Groothengel, Marin; van de Grint, Liesbeth; Karssenberg, Derek; Stouthamer, Esther

    2017-04-01

    Excursions and fieldworks are valuable components for geosciences education. However, field activities can be time consuming for teachers and pose a logistical challenge to fit in regular courses. Furthermore, the participation of students diminishes with group size in case of instructor-led outings. We are developing excursions that students can follow autonomously without a teacher present, using instructions, assignments and background information on tablets and smartphones. The goal of this approach is to increase the level of active participation, and to reduce logistical and time table issues. We developed a bike-excursion about the landscape and geology in the vicinity of our University. Such excursion was on the wish-list for several years, but posed a logistical challenge for the group of about 80 students in the available timeslot. In our approach, students had a time-window of two weeks in which they could finish the excursion in groups of 2. 8-Inch tablets with water- and shock-proof cases were available for this excursion. For the excursion we used three apps: 1) IZI-Travel for providing the route, spoken navigation instructions, spoken explanations at stops, location-related images, assignments as text, and multiple-choose questions. 2) PDF-Maps for providing geo-referenced maps. 3) ESRI Collector which the students used to digitize polygons on a map, and to collect geo-referenced photos with explanation. These data were answers to assignments and were later used in a tutorial on campus. The assignments where students had to collect data, and the small group size (pairs) increased the level of active participation. The use of a final tutorial on campus was important for the autonomous excursion, as it gave students the opportunity to discuss their observations and questions with their teacher. The developed teaching materials are available online to use and adapt for others. Parts could be useful for other universities and schools in the vicinity of the excursion location.

  6. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Ferries, excursion boats and other vessels. [Reserved] 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH....177 Ferries, excursion boats and other vessels. [Reserved] ...

  7. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Ferries, excursion boats and other vessels. [Reserved] 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH....177 Ferries, excursion boats and other vessels. [Reserved] ...

  8. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Ferries, excursion boats and other vessels. [Reserved] 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH....177 Ferries, excursion boats and other vessels. [Reserved] ...

  9. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Ferries, excursion boats and other vessels. [Reserved] 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH....177 Ferries, excursion boats and other vessels. [Reserved] ...

  10. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Ferries, excursion boats and other vessels. [Reserved] 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH....177 Ferries, excursion boats and other vessels. [Reserved] ...

  11. Efficient designs for powering microscale devices with nanoscale biomolecular motors.

    PubMed

    Lin, Chih-Ting; Kao, Ming-Tse; Kurabayashi, Katsuo; Meyhöfer, Edgar

    2006-02-01

    Current MEMS and microfluidic designs require external power sources and actuators, which principally limit such technology. To overcome these limitations, we have developed a number of microfluidic systems into which we can seamlessly integrate a biomolecular motor, kinesin, that transports microtubules by extracting chemical energy from its aqueous working environment. Here we establish that our microfabricated structures, the self-assembly of the bio-derived transducer, and guided, unidirectional transport of microtubules are ideally suited to create engineered arrays for efficiently powering nano- and microscale devices.

  12. Comparison of longitudinal excursion of a nerve-phantom model using quantitative ultrasound imaging and motion analysis system methods: A convergent validity study.

    PubMed

    Paquette, Philippe; El Khamlichi, Youssef; Lamontagne, Martin; Higgins, Johanne; Gagnon, Dany H

    2017-08-01

    Quantitative ultrasound imaging is gaining popularity in research and clinical settings to measure the neuromechanical properties of the peripheral nerves such as their capability to glide in response to body segment movement. Increasing evidence suggests that impaired median nerve longitudinal excursion is associated with carpal tunnel syndrome. To date, psychometric properties of longitudinal nerve excursion measurements using quantitative ultrasound imaging have not been extensively investigated. This study investigates the convergent validity of the longitudinal nerve excursion by comparing measures obtained using quantitative ultrasound imaging with those determined with a motion analysis system. A 38-cm long rigid nerve-phantom model was used to assess the longitudinal excursion in a laboratory environment. The nerve-phantom model, immersed in a 20-cm deep container filled with a gelatin-based solution, was moved 20 times using a linear forward and backward motion. Three light-emitting diodes were used to record nerve-phantom excursion with a motion analysis system, while a 5-cm linear transducer allowed simultaneous recording via ultrasound imaging. Both measurement techniques yielded excellent association ( r  = 0.99) and agreement (mean absolute difference between methods = 0.85 mm; mean relative difference between methods = 7.48 %). Small discrepancies were largely found when larger excursions (i.e. > 10 mm) were performed, revealing slight underestimation of the excursion by the ultrasound imaging analysis software. Quantitative ultrasound imaging is an accurate method to assess the longitudinal excursion of an in vitro nerve-phantom model and appears relevant for future research protocols investigating the neuromechanical properties of the peripheral nerves.

  13. Dynamics of the earth magnetic field in the 10-75 kyr period comprising the Laschamp and Mono Lake excursions: New results from the French Chaîne des Puys in a global perspective

    NASA Astrophysics Data System (ADS)

    Laj, Carlo; Guillou, Hervé; Kissel, Catherine

    2014-02-01

    We report here on a new paleomagnetic (directions and intensities) and coupled K/Ar and 40Ar/39Ar analysis of 35 different flows, emplaced in the Chaîne des Puys during the 75 to 10 kyr interval, which contains the Mono Lake and Laschamp excursions. There is a remarkable agreement between the new set of absolute volcanic intensities and published sedimentary (GLOPIS-75) and cosmogenic (10Be and 36Cl) records. The Laschamp and Mono Lake excursions are clearly revealed by a very significant intensity drop at 41.2±1.6 ka and 34.2±1.2 ka respectively. The duration of the Laschamp excursion is ˜1500 yr and about 640 yr when the drop of paleointensity or the directional change are considered respectively. The intensity drop at the Mono Lake is twice as short. In the ˜7 ka interval separating the two excursions, the field intensity recovers to almost non-transitional values. The rate of decrease of the field intensity during these excursions attains 18 nT/yr for the Laschamp and even greater value (33 nT/yr) for the Mono Lake. This figure is, for the Laschamp excursion, similar to the present field intensity decrease in the last two centuries so that one may wonder whether such a high rate of change may be characteristic of an impending geomagnetic event (reversal or excursion). We suggest that the name Auckland excursion should be used for the present-day called Mono Lake.

  14. Condylar motion in children with primary dentition during lateral excursion.

    PubMed

    Yamasaki, Youichi; Hayasaki, Haruaki; Nishi, Megumi; Nakata, Shiho; Nakata, Minoru

    2002-07-01

    Normal development of primary and mixed dentition is indispensable for establishing a healthy mandibular function of the permanent dentition. Because condylar movements are crucial for mandibular function, extensive studies have been reported. However, most of these studies have dealt with mandibular functions in adults, and there is less known about children with primary dentition. The purpose of this study was to clarify the condylar movements during lateral excursions in children with primary dentition and compare these movements with those of adults from the viewpoint of functional development. With use of an optoelectronic recording system with six degrees of freedom, the lateral excursions of 24 children and 20 young women, with sound dentition, were recorded at 100 Hz. The results show that the balancing side condyle of the children had a significantly smaller vertical excursion and a significantly larger anteroposterior excursion than that of adults, indicating the shallower and more anteriorly directed movements of the entire mandible during lateral excursions in children with primary dentition.

  15. Horizontal and vertical movements of Caribbean reef sharks (Carcharhinus perezi): conservation implications of limited migration in a marine sanctuary

    PubMed Central

    Howey, Lucy A.; Tolentino, Emily R.; Jordan, Lance K. B.; Ruppert, Jonathan L. W.; Brooks, Edward J.

    2017-01-01

    Despite the ecological and economic importance of the Caribbean reef shark (Carcharhinus perezi), little data exist regarding the movements and habitat use of this predator across its range. We deployed 11 pop-up satellite archival tags on Caribbean reef sharks captured in the northeast Exuma Sound, The Bahamas, to assess their horizontal and vertical movements throughout the water column. Sharks showed high site fidelity to The Bahamas suggesting Bahamian subpopulations remain protected within the Bahamian Shark Sanctuary. Depth data indicate that Caribbean reef sharks spent a significant proportion (72–91%) of their time above 50 m in narrow vertical depth bands, which varied considerably on an individual basis. This may be indicative of high site fidelity to specific bathymetric features. Animals exhibited three broadly categorized sporadic off-bank excursions (more than 50 m excursions) down to a depth of 436.1 m, which were more frequent during the night. These deeper excursions during night may be indicative of foraging in relation to prey on mesophotic reefs, as well as diel-vertically migrating prey from the deeper meso- and bathypelagic zones. These vertical movements suggest that Caribbean reef sharks can be significant vectors of ecosystem connectivity further warranting holistic multi-system management and conservation approaches. PMID:28386422

  16. Horizontal and vertical movements of Caribbean reef sharks (Carcharhinus perezi): conservation implications of limited migration in a marine sanctuary.

    PubMed

    Shipley, Oliver N; Howey, Lucy A; Tolentino, Emily R; Jordan, Lance K B; Ruppert, Jonathan L W; Brooks, Edward J

    2017-02-01

    Despite the ecological and economic importance of the Caribbean reef shark ( Carcharhinus perezi ), little data exist regarding the movements and habitat use of this predator across its range. We deployed 11 pop-up satellite archival tags on Caribbean reef sharks captured in the northeast Exuma Sound, The Bahamas, to assess their horizontal and vertical movements throughout the water column. Sharks showed high site fidelity to The Bahamas suggesting Bahamian subpopulations remain protected within the Bahamian Shark Sanctuary. Depth data indicate that Caribbean reef sharks spent a significant proportion (72-91%) of their time above 50 m in narrow vertical depth bands, which varied considerably on an individual basis. This may be indicative of high site fidelity to specific bathymetric features. Animals exhibited three broadly categorized sporadic off-bank excursions (more than 50 m excursions) down to a depth of 436.1 m, which were more frequent during the night. These deeper excursions during night may be indicative of foraging in relation to prey on mesophotic reefs, as well as diel-vertically migrating prey from the deeper meso- and bathypelagic zones. These vertical movements suggest that Caribbean reef sharks can be significant vectors of ecosystem connectivity further warranting holistic multi-system management and conservation approaches.

  17. Simulator study of the effectiveness of an automatic control system designed to improve the high-angle-of-attack characteristics of a fighter airplane

    NASA Technical Reports Server (NTRS)

    Gilbert, W. P.; Nguyen, L. T.; Vangunst, R. W.

    1976-01-01

    A piloted, fixed-base simulation was conducted to study the effectiveness of some automatic control system features designed to improve the stability and control characteristics of fighter airplanes at high angles of attack. These features include an angle-of-attack limiter, a normal-acceleration limiter, an aileron-rudder interconnect, and a stability-axis yaw damper. The study was based on a current lightweight fighter prototype. The aerodynamic data used in the simulation were measured on a 0.15-scale model at low Reynolds number and low subsonic Mach number. The simulation was conducted on the Langley differential maneuvering simulator, and the evaluation involved representative combat maneuvering. Results of the investigation show the fully augmented airplane to be quite stable and maneuverable throughout the operational angle-of-attack range. The angle-of-attack/normal-acceleration limiting feature of the pitch control system is found to be a necessity to avoid angle-of-attack excursions at high angles of attack. The aileron-rudder interconnect system is shown to be very effective in making the airplane departure resistant while the stability-axis yaw damper provided improved high-angle-of-attack roll performance with a minimum of sideslip excursions.

  18. RACLETTE: a model for evaluating the thermal response of plasma facing components to slow high power plasma transients. Part II: Analysis of ITER plasma facing components

    NASA Astrophysics Data System (ADS)

    Federici, Gianfranco; Raffray, A. René

    1997-04-01

    The transient thermal model RACLETTE (acronym of Rate Analysis Code for pLasma Energy Transfer Transient Evaluation) described in part I of this paper is applied here to analyse the heat transfer and erosion effects of various slow (100 ms-10 s) high power energy transients on the actively cooled plasma facing components (PFCs) of the International Thermonuclear Experimental Reactor (ITER). These have a strong bearing on the PFC design and need careful analysis. The relevant parameters affecting the heat transfer during the plasma excursions are established. The temperature variation with time and space is evaluated together with the extent of vaporisation and melting (the latter only for metals) for the different candidate armour materials considered for the design (i.e., Be for the primary first wall, Be and CFCs for the limiter, Be, W, and CFCs for the divertor plates) and including for certain cases low-density vapour shielding effects. The critical heat flux, the change of the coolant parameters and the possible severe degradation of the coolant heat removal capability that could result under certain conditions during these transients, for example for the limiter, are also evaluated. Based on the results, the design implications on the heat removal performance and erosion damage of the variuos ITER PFCs are critically discussed and some recommendations are made for the selection of the most adequate protection materials and optimum armour thickness.

  19. Finite element comparison of human and Hybrid III responses in a frontal impact.

    PubMed

    Danelson, Kerry A; Golman, Adam J; Kemper, Andrew R; Gayzik, F Scott; Clay Gabler, H; Duma, Stefan M; Stitzel, Joel D

    2015-12-01

    The improvement of finite element (FE) Human Body Models (HBMs) has made them valuable tools for investigating restraint interactions compared to anthropomorphic test devices (ATDs). The objective of this study was to evaluate the effect of various combinations of safety restraint systems on the sensitivity of thoracic injury criteria using matched ATD and Human Body Model (HBM) simulations at two crash severities. A total of seven (7) variables were investigated: 3-point belt with two (2) load limits, frontal airbag, knee bolster airbag, a buckle pretensioner, and two (2) delta-v's - 40kph and 50kph. Twenty four (24) simulations were conducted for the Hybrid III ATD FE model and repeated with a validated HBM for 48 total simulations. Metrics tested in these conditions included sternum deflection, chest acceleration, chest excursion, Viscous Criteria (V*C) criteria, pelvis acceleration, pelvis excursion, and femur forces. Additionally, chest band deflection and rib strain distribution were measured in the HBM for additional restraint condition discrimination. The addition of a frontal airbag had the largest effect on the occupant chest metrics with an increase in chest compression and acceleration but a decrease in excursion. While the THUMS and Hybrid III occupants demonstrated the same trend in the chest compression measurements, there were conflicting results in the V*C, acceleration, and displacement metrics. Similarly, the knee bolster airbag had the largest effect on the pelvis with a decrease in acceleration and excursion. With a knee bolster airbag the simulated occupants gave conflicting results, the THUMS had a decrease in femur force and the ATD had an increase. Preferential use of dummies or HBM's is not debated; however, this study highlights the ability of HBM metrics to capture additional chest response metrics. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Precision measurement of the local bias of dark matter halos

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

    Lazeyras, Titouan; Wagner, Christian; Schmidt, Fabian

    2016-02-01

    We present accurate measurements of the linear, quadratic, and cubic local bias of dark matter halos, using curved 'separate universe' N-body simulations which effectively incorporate an infinite-wavelength overdensity. This can be seen as an exact implementation of the peak-background split argument. We compare the results with the linear and quadratic bias measured from the halo-matter power spectrum and bispectrum, and find good agreement. On the other hand, the standard peak-background split applied to the Sheth and Tormen (1999) and Tinker et al. (2008) halo mass functions matches the measured linear bias parameter only at the level of 10%. The predictionmore » from the excursion set-peaks approach performs much better, which can be attributed to the stochastic moving barrier employed in the excursion set-peaks prediction. We also provide convenient fitting formulas for the nonlinear bias parameters b{sub 2}(b{sub 1}) and b{sub 3}(b{sub 1}), which work well over a range of redshifts.« less

  1. From Belief to Action: Omani EFL Teachers' Self-Efficacy in Relation to Their Teaching of English as a Foreign Language

    ERIC Educational Resources Information Center

    Al-Shukri, Abdullah Khamis

    2016-01-01

    Research has documented that teacher self-efficacy has positive impacts on different aspects of teaching and learning. Yet, research on teacher self-efficacy in the field of teaching English as a Foreign Language (EFL) is relatively limited. Considering the powerful impacts of teacher self-efficacy on teaching and learning, it is crucial to pursue…

  2. 46 CFR 2.01-45 - Excursion permit.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., on Coast Guard Form CG-950, Application for Excursion Permit. If, after inspection, permission is... the application process for excursion permits for inspected passenger vessels are contained in §§ 71.10, 115.204, or 176.204 of this chapter. Details concerning the application process for special...

  3. High temperature furnace

    DOEpatents

    Borkowski, Casimer J.

    1976-08-03

    A high temperature furnace for use above 2000.degree.C is provided that features fast initial heating and low power consumption at the operating temperature. The cathode is initially heated by joule heating followed by electron emission heating at the operating temperature. The cathode is designed for routine large temperature excursions without being subjected to high thermal stresses. A further characteristic of the device is the elimination of any ceramic components from the high temperature zone of the furnace.

  4. The Experiential Learning Impact of International and Domestic Study Tours: Class Excursions That Are More than Field Trips

    ERIC Educational Resources Information Center

    Gomez-Lanier, Lilia

    2017-01-01

    Experiential education programs, such as international and domestic study tours, bridge the limitations of formal learning classroom by allowing students to experience reality in a new learning dimension. This mixed-methods study explores experiential learning during a domestic interior design study tour to New York City and an international…

  5. Geologist's Field Assistant: Developing Image and Spectral Analyses Algorithms for Remote Science Exploration

    NASA Technical Reports Server (NTRS)

    Gulick, V. C.; Morris, R. L.; Bishop, J.; Gazis, P.; Alena, R.; Sierhuis, M.

    2002-01-01

    We are developing science analyses algorithms to interface with a Geologist's Field Assistant device to allow robotic or human remote explorers to better sense their surroundings during limited surface excursions. Our algorithms will interpret spectral and imaging data obtained by various sensors. Additional information is contained in the original extended abstract.

  6. 46 CFR 115.204 - Permit to carry excursion party.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... jacket, fire safety, and manning standards applicable to a vessel in the service for which the excursion... crew required, any additional lifesaving or safety equipment required, the route for which the permit... applicable minimum safety standards when issuing an excursion permit. In particular, a vessel that is being...

  7. 46 CFR 115.204 - Permit to carry excursion party.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... jacket, fire safety, and manning standards applicable to a vessel in the service for which the excursion... crew required, any additional lifesaving or safety equipment required, the route for which the permit... applicable minimum safety standards when issuing an excursion permit. In particular, a vessel that is being...

  8. 46 CFR 115.204 - Permit to carry excursion party.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... jacket, fire safety, and manning standards applicable to a vessel in the service for which the excursion... crew required, any additional lifesaving or safety equipment required, the route for which the permit... applicable minimum safety standards when issuing an excursion permit. In particular, a vessel that is being...

  9. 40 CFR 63.1438 - Parameter monitoring levels and excursions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... required to submit Periodic Reports semiannually or quarterly. The first semiannual period is the 6-month... excursions. (5) For the fifth semiannual period—two excused excursions. (6) For the sixth and all subsequent... during the entire test period. The monitoring level(s) shall be those established during from the...

  10. 40 CFR 63.1438 - Parameter monitoring levels and excursions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... required to submit Periodic Reports semiannually or quarterly. The first semiannual period is the 6-month... excursions. (5) For the fifth semiannual period—two excused excursions. (6) For the sixth and all subsequent... during the entire test period. The monitoring level(s) shall be those established during from the...

  11. 40 CFR 63.1438 - Parameter monitoring levels and excursions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... required to submit Periodic Reports semiannually or quarterly. The first semiannual period is the 6-month... excursions. (5) For the fifth semiannual period—two excused excursions. (6) For the sixth and all subsequent... during the entire test period. The monitoring level(s) shall be those established during from the...

  12. 40 CFR 63.1438 - Parameter monitoring levels and excursions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... required to submit Periodic Reports semiannually or quarterly. The first semiannual period is the 6-month... excursions. (5) For the fifth semiannual period—two excused excursions. (6) For the sixth and all subsequent... during the entire test period. The monitoring level(s) shall be those established during from the...

  13. 36 CFR 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Ferries, excursion boats and other vessels. [Reserved] 1192.177 Section 1192.177 Parks, Forests, and Public Property ARCHITECTURAL... GUIDELINES FOR TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and...

  14. 36 CFR 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Ferries, excursion boats and other vessels. [Reserved] 1192.177 Section 1192.177 Parks, Forests, and Public Property ARCHITECTURAL... GUIDELINES FOR TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and...

  15. 36 CFR 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Ferries, excursion boats and other vessels. [Reserved] 1192.177 Section 1192.177 Parks, Forests, and Public Property ARCHITECTURAL... GUIDELINES FOR TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and...

  16. 36 CFR 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Ferries, excursion boats and other vessels. [Reserved] 1192.177 Section 1192.177 Parks, Forests, and Public Property ARCHITECTURAL... GUIDELINES FOR TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and...

  17. Free gracilis transfer for smile in children: the Massachusetts Eye and Ear Infirmary Experience in excursion and quality-of-life changes.

    PubMed

    Hadlock, Tessa A; Malo, Juan S; Cheney, Mack L; Henstrom, Douglas K

    2011-01-01

    Free muscle transfer for facial reanimation has become the standard of care in recent decades and is now the cornerstone intervention for dynamic smile reanimation. We sought to quantify smile excursion and quality-of-life (QOL) changes in our pediatric free gracilis recipients following reanimation. We quantified gracilis muscle excursion in 17 pediatric patients undergoing 19 consecutive pediatric free gracilis transplantation operations, using our validated SMILE program, as an objective measure of functional outcome. These were compared against excursion measured the same way in a cohort of 17 adults with 19 free gracilis operations. In addition, we prospectively evaluated QOL outcomes in these children using the Facial Clinimetric Evaluation (FaCE) instrument. The mean gracilis excursion in our pediatric free gracilis recipients was 8.8 mm ± 5.0 mm, which matched adult results, but with fewer complete failures of less than 2-mm excursion, with 2 (11%) and 4 (21%), respectively. Quality-of-life measures indicated statistically significant improvements following dynamic smile reanimation (P = .01). Dynamic facial reanimation using free gracilis transfer in children has an acceptable success rate, yields improved commissure excursion, and improves QOL in the pediatric population. It should be considered first-line therapy for children with lack of a meaningful smile secondary to facial paralysis.

  18. The Blake geomagnetic excursion recorded in a radiometrically dated speleothem

    NASA Astrophysics Data System (ADS)

    Osete, María-Luisa; Martín-Chivelet, Javier; Rossi, Carlos; Edwards, R. Lawrence; Egli, Ramon; Muñoz-García, M. Belén; Wang, Xianfeng; Pavón-Carrasco, F. Javier; Heller, Friedrich

    2012-11-01

    One of the most important developments in geomagnetism has been the recognition of polarity excursions of the Earth's magnetic field. Accurate timing of the excursions is a key point for understanding the geodynamo process and for magnetostratigraphic correlation. One of the best-known excursions is the Blake geomagnetic episode, which occurred during marine isotope stage MIS 5, but its morphology and age remain controversial. Here we show, for the first time, the Blake excursion recorded in a stalagmite which was dated using the uranium-series disequilibrium techniques. The characteristic remanent magnetisation is carried by fine-grained magnetite. The event is documented by two reversed intervals (B1 and B2). The age of the event is estimated to be between 116.5±0.7 kyr BP and 112.0±1.9 kyr BP, slightly younger (∼3-4 kyr) than recent estimations from sedimentary records dated by astronomical tuning. Low values of relative palaeointensity during the Blake episode are estimated, but a relative maximum in the palaeofield intensity coeval with the complete reversal during the B2 interval was observed. Duration of the Blake geomagnetic excursion is 4.5 kyr, two times lower than single excursions and slightly higher than the estimated diffusion time for the inner core (∼3 kyr).

  19. An Evaluation of the British Columbia Asthma Monitoring System (BCAMS) and PM2.5 Exposure Metrics during the 2014 Forest Fire Season

    PubMed Central

    McLean, Kathleen E.; Yao, Jiayun; Henderson, Sarah B.

    2015-01-01

    The British Columbia Asthma Monitoring System (BCAMS) tracks forest fire smoke exposure and asthma-related health outcomes, identifying excursions beyond expected daily counts. Weekly reports during the wildfire season support public health and emergency management decision-making. We evaluated BCAMS by identifying excursions for asthma-related physician visits and dispensations of the reliever medication salbutamol sulfate and examining their corresponding smoke exposures. A disease outbreak detection algorithm identified excursions from 1 July to 31 August 2014. Measured, modeled, and forecasted concentrations of fine particulate matter (PM2.5) were used to assess exposure. We assigned PM2.5 levels to excursions by choosing the highest value within a seven day window centred on the excursion day. Smoky days were defined as those with PM2.5 levels ≥ 25 µg/m3. Most excursions (57%–71%) were assigned measured or modeled PM2.5 concentrations of 10 µg/m3 or higher. Of the smoky days, 55.8% and 69.8% were associated with at least one excursion for physician visits and salbutamol dispensations, respectively. BCAMS alerted most often when measures of smoke exposure were relatively high. Better performance might be realized by combining asthma-related outcome metrics in a bivariate model. PMID:26075727

  20. Atmospheric Carbon Dioxide and its Relation to Carbon Cycle Perturbations During Ocean Anoxic Event 1d: A High Resolution Record From Dispersed Plant Cuticle

    NASA Astrophysics Data System (ADS)

    Richey, J. D.; Upchurch, G. R.; Joeckel, R.; Smith, J. J.; Ludvigson, G. A.; Lomax, B. H.

    2013-12-01

    Past geological greenhouse intervals are associated with Ocean Anoxic Events (OAEs), which result from an increase in marine primary productivity and/or an increase in the preservation of organic matter. The end point is widespread black shale deposition combined with a long-term atmospheric positive δ13C excursion and an increase in the burial of 12C. Some OAEs show a negative δ13C excursion preceding the positive excursion, indicating a perturbation in the global carbon cycle prior to the initiation of these events. The Rose Creek (RCP) locality, southeastern Nebraska, is the only known terrestrial section that preserves OAE1d (Cretaceous, Albian-Cenomanian Boundary) and has abundant charcoal and plant cuticle. These features allow for a combined carbon isotope and stomatal index (SI) analysis to determine both changes in the cycling between carbon pools (C isotope analysis) and changes in paleo-CO2 via changes in SI. Preliminary (and ongoing) SI data analysis using dispersed cuticle of Pandemophyllum kvacekii (an extinct Laurel) collected at 30 cm intervals indicate changes in SI consistent with changes in CO2. Fitting our samples to a published RCP δ13C profile, pre-excursion CO2 concentrations are high. CO2 decreases to lower concentrations in the basal 1.2 m of the RCP section, where δ13Cbulk shows a negative excursion and δ13Ccharcoal remains at pre-excursion values. CO2 concentrations become higher toward the top of the negative δ13C excursion, where δ13Cbulk and δ13Ccharcoal are at their most negative values, and drop as the negative carbon excursion terminates. Using published transfer functions, we estimate that pre-excursion CO2 concentrations were a maximum of 900 ppm. In the basal 1.2 m of RCP, CO2 drops to a maximum of 480 ppm, and rises to a maximum of 710 ppm near the top of the negative excursion. As δ13C values rise towards pre-excursion values, CO2 declines to a maximum of 400 ppm. The trend in SI is comparable to the trend in δ13Ccharcoal and follows recognized patterns, while SI shows partial divergence from δ13Cbulk. These data, while preliminary, highlight the importance of considering isotope substrate when investigating carbon cycle perturbations.

  1. The Precambrian Biogeochemical Carbon Isotopic Record: Contributions of Thermal Versus Biological Processes

    NASA Technical Reports Server (NTRS)

    DesMarais, David J.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Superplumes offer a new approach for understanding global C cycles. Isotopes help to discern the impacts of geological, environmental and biological processes ujpun the evolution of these cycles. For example, C-13/C-12 values of coeval sedimentary organics and carbonates give global estimates of the fraction of C buried as organics (Forg), which today lies near 0.2. Before Oxygenic photosynthesis arose, our biosphere obtained reducing power for biosynthesis solely from thermal volatiles and rock alteration. Thus Forg was dominated by the mantle redox state, which has remained remarkably constant for greater than Gy. Recent data confirm that the long-term change in Forg had been small, indicating that the mantle redox buffer remains important even today. Oxygenic photosynthesis enabled life to obtain additional reducing power by splitting the water molecule. Accordingly, biological organic production rose above the level constrained by the mantle-derived flux of reduced species. For example, today, chemoautotrophs harvesting energy from hydrothermal emanations can synthesize at most between 0.2 x 10(exp 12) and 2x 10(exp 12) mol C yr-1 of organic C globally. In contrast, global photosynthetic productivity is estimated at 9000 x 10(exp 12) mol C yr-1. Occasionally photosynthetic productivity did contribute to dramatically -elevated Forg values (to 0.4 or more) as evidenced by very high carbonate C-13/C-12. The interplay between biological, tectonic and other environmental factors is illustrated by the mid-Archean to mid-Proterozoic isotopic record. The relatively constant C-13/C-12 values of Archean carbonates support the view that photosynthetically-driven Forg increases were not yet possible. In contrast, major excursions in C-13/C-12, and thus also in Forg, during the early Proterozoic confirmed the global importance of oxygenic photosynthesis by that time. Remarkably, the superplume event at 1.9 Ga did not trigger another major Forg increase, despite the favorable conditions for organic burial that were evidenced by elevated sea levels and higher black shale abundances. Perhaps those superplume-rated processes that favored enhanced organic burial were offset by the ability of mantle-derived redox buffering, which was enhanced during the superplume event, to limit excursions in Forg.

  2. Laser beam self-focusing in turbulent dissipative media.

    PubMed

    Hafizi, B; Peñano, J R; Palastro, J P; Fischer, R P; DiComo, G

    2017-01-15

    A high-power laser beam propagating through a dielectric in the presence of fluctuations is subject to diffraction, dissipation, and optical Kerr nonlinearity. A method of moments was applied to a stochastic, nonlinear enveloped wave equation to analyze the evolution of the long-term spot radius. For propagation in atmospheric turbulence described by a Kolmogorov-von Kármán spectral density, the analysis was benchmarked against field experiments in the low-power limit and compared with simulation results in the high-power regime. Dissipation reduced the effect of self-focusing and led to chromatic aberration.

  3. Self-organization and self-limitation in high power impulse magnetron sputtering

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

    Anders, Andre

    The plasma over the racetrack in high power impulse magnetron sputtering develops in traveling ionization zones. Power densities can locally reach 10{sup 9} W/m{sup 2}, which is much higher than usually reported. Ionization zones move because ions are 'evacuated' by the electric field, exposing neutrals to magnetically confined, drifting electrons. Drifting secondary electrons amplify ionization of the same ionization zone where the primary ions came from, while sputtered and outgassing atoms are supplied to the following zone(s). Strong density gradients parallel to the target disrupt electron confinement: a negative feedback mechanism that stabilizes ionization runaway.

  4. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  5. 36 CFR § 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Ferries, excursion boats and other vessels. [Reserved] § 1192.177 Section § 1192.177 Parks, Forests, and Public Property... GUIDELINES FOR TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and...

  6. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  7. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  8. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  9. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  10. Cruising through Research: Library Skills for Young Adults.

    ERIC Educational Resources Information Center

    Volkman, John D.

    This book presents an approach for school librarians to use to introduce basic research tools to students in grades 7-12. Twelve "Excursions" (i.e., library research projects) are described. Excursions 1 and 2 provide an introduction to reference books, and Excursions 3 and 4 explore note-taking and basic organization of research papers. The…

  11. Weakly Nonergodic Dynamics in the Gross-Pitaevskii Lattice

    NASA Astrophysics Data System (ADS)

    Mithun, Thudiyangal; Kati, Yagmur; Danieli, Carlo; Flach, Sergej

    2018-05-01

    The microcanonical Gross-Pitaevskii (also known as the semiclassical Bose-Hubbard) lattice model dynamics is characterized by a pair of energy and norm densities. The grand canonical Gibbs distribution fails to describe a part of the density space, due to the boundedness of its kinetic energy spectrum. We define Poincaré equilibrium manifolds and compute the statistics of microcanonical excursion times off them. The tails of the distribution functions quantify the proximity of the many-body dynamics to a weakly nonergodic phase, which occurs when the average excursion time is infinite. We find that a crossover to weakly nonergodic dynamics takes place inside the non-Gibbs phase, being unnoticed by the largest Lyapunov exponent. In the ergodic part of the non-Gibbs phase, the Gibbs distribution should be replaced by an unknown modified one. We relate our findings to the corresponding integrable limit, close to which the actions are interacting through a short range coupling network.

  12. Sedimentary and Volcanic Records of the Laschamp and Mono Lake Excursions from Australia and New Zealand

    NASA Astrophysics Data System (ADS)

    Ingham, E. M.; Roberts, A. P.; Turner, G. M.; Heslop, D.; Ronge, T.; Conway, C.; Leonard, G.; Townsend, D.; Tiedemann, R.; Lamy, F.; Calvert, A. T.

    2014-12-01

    Geomagnetic excursions are short-lived deviations of the geomagnetic field from the normal range of secular variation. Despite significant advances in geomagnetic excursion research over the past 20 years, fundamental questions remain concerning the typical duration and global morphology of excursional geomagnetic fields. To answer such questions, more high-resolution, chronologically well-constrained excursion records are required, particularly from the Southern Hemisphere. We present preliminary paleomagnetic records of the Laschamp (~41 ka) and Mono Lake (~35 ka) excursions from three marine sediment cores from the Bounty Trough, New Zealand margin, and complementary volcanic records of the Laschamp excursion from lavas of Mt Ruapehu, New Zealand. Relatively high sedimentation rates of 12 - 26 cm/kyr in the Bounty Trough during glacial periods allow identification of excursional field behavior at each of the studied core locations. Each core displays one or two excursional events, with rapid directional swings between stable normal polarity and reversed excursional directions, each associated with coincident relative paleointensity minima. These anomalous paleomagnetic directions are interpreted to represent the Laschamp and Mono Lake excursions, based on a combination of tephrochronology, radiocarbon dating, and cyclostratigraphy (defined from core-scanning X-ray fluorescence and magnetic susceptibility records). Beside these records, we present results from fourteen lava flows, on Mt Ruapehu, for which 40Ar-39Ar dating indicates ages of between 39 and 45 ka. The step heating 40Ar-39Ar experiments produced particularly flat age plateaus, with corresponding 2 s.d. errors mostly approaching 1 kyr. The youngest and oldest flows carry normal polarity magnetization, however six flows, dated between 41 and 43 ka, display transitional field characteristics. Three of these flows display a declination swing of around 180o, which coincides with a previously published result from the Auckland Basalt Field. Together, these data provide rare excursion records from the southern hemisphere, which will provide an improved view of geomagnetic field morphology during these excursions.

  13. ODP Site 1063 (Bermuda Rise) revisited: Oxygen isotopes, excursions and paleointensity in the Brunhes Chron

    NASA Astrophysics Data System (ADS)

    Channell, J. E. T.; Hodell, D. A.; Curtis, J. H.

    2012-02-01

    An age model for the Brunhes Chron of Ocean Drilling Program (ODP) Site 1063 (Bermuda Rise) is constructed by tandem correlation of oxygen isotope and relative paleointensity data to calibrated reference templates. Four intervals in the Brunhes Chron where paleomagnetic inclinations are negative for both u-channel samples and discrete samples are correlated to the following magnetic excursions with Site 1063 ages in brackets: Laschamp (41 ka), Blake (116 ka), Iceland Basin (190 ka), Pringle Falls (239 ka). These ages are consistent with current age estimates for three of these excursions, but not for "Pringle Falls" which has an apparent age older than a recently published estimate by ˜28 kyr. For each of these excursions (termed Category 1 excursions), virtual geomagnetic poles (VGPs) reach high southerly latitudes implying paired polarity reversals of the Earth's main dipole field, that apparently occurred in a brief time span (<2 kyr in each case), several times shorter than the apparent duration of regular polarity transitions. In addition, several intervals of low paleomagnetic inclination (low and negative in one case) are observed both in u-channel and discrete samples at ˜318 ka (MIS 9), ˜412 ka (MIS 11) and in the 500-600 ka interval (MIS 14-15). These "Category 2" excursions may constitute inadequately recorded (Category 1) excursions, or high amplitude secular variation.

  14. Self-heating and failure in scalable graphene devices

    DOE PAGES

    Beechem, Thomas E.; Shaffer, Ryan A.; Nogan, John; ...

    2016-06-09

    Self-heating induced failure of graphene devices synthesized from both chemical vapor deposition (CVD) and epitaxial means is compared using a combination of infrared thermography and Raman imaging. Despite a larger thermal resistance, CVD devices dissipate >3x the amount of power before failure than their epitaxial counterparts. The discrepancy arises due to morphological irregularities implicit to the graphene synthesis method that induce localized heating. As a result, morphology, rather than thermal resistance, therefore dictates power handling limits in graphene devices.

  15. Self-teaching neural network learns difficult reactor control problem

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

    Jouse, W.C.

    1989-01-01

    A self-teaching neural network used as an adaptive controller quickly learns to control an unstable reactor configuration. The network models the behavior of a human operator. It is trained by allowing it to operate the reactivity control impulsively. It is punished whenever either the power or fuel temperature stray outside technical limits. Using a simple paradigm, the network constructs an internal representation of the punishment and of the reactor system. The reactor is constrained to small power orbits.

  16. Suspended-sediment flux and retention in a backwater tidal slough complex near the landward boundary of an estuary

    USGS Publications Warehouse

    Morgan-King, Tara L.; Schoellhamer, David H.

    2013-01-01

    Backwater tidal sloughs are commonly found at the landward boundary of estuaries. The Cache Slough complex is a backwater tidal region within the Upper Sacramento–San Joaquin Delta that includes two features that are relevant for resource managers: (1) relatively high abundance of the endangered fish, delta smelt (Hypomesus transpacificus), which prefers turbid water and (2) a recently flooded shallow island, Liberty Island, that is a prototype for habitat restoration. We characterized the turbidity around Liberty Island by measuring suspended-sediment flux at four locations from July 2008 through December 2010. An estuarine turbidity maximum in the backwater Cache Slough complex is created by tidal asymmetry, a limited tidal excursion, and wind-wave resuspension. During the study, there was a net export of sediment, though sediment accumulates within the region from landward tidal transport during the dry season. Sediment is continually resuspended by both wind waves and flood tide currents. The suspended-sediment mass oscillates within the region until winter freshwater flow pulses flush it seaward. The hydrodynamic characteristics within the backwater region such as low freshwater flow during the dry season, flood tide dominance, and a limited tidal excursion favor sediment retention.

  17. Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals.

    PubMed Central

    LaMontagne, A D; Kelsey, K T

    2001-01-01

    OBJECTIVES: This study sought to identify determinants of workplace exposures to ethylene oxide to assess the effect of the Occupational Safety and Health Administration's (OSHA's) 1984 ethylene oxide standard. METHODS: An in-depth survey of all hospitals in Massachusetts that used ethylene oxide from 1990 through 1992 (96% participation, N = 90) was conducted. Three types of exposure events were modeled with logistic regression: exceeding the 8-hour action level, exceeding the 15-minute excursion limit, and worker exposures during unmeasured accidental releases. Covariates were drawn from data representing an ecologic framework including direct and indirect potential exposure determinants. RESULTS: After adjustment for frequencies of ethylene oxide use and exposure monitoring, a significant inverse relation was observed between exceeding the action level and the use of combined sterilizer-aerators, an engineering control technology developed after the passage of the OSHA standard. Conversely, the use of positive-pressure sterilizers that employ ethylene oxide gas mixtures was strongly related to both exceeding the excursion limit and the occurrence of accidental releases. CONCLUSIONS: These findings provide evidence of a positive effect of OSHA's ethylene oxide standard and specific targets for future prevention and control efforts. PMID:11236406

  18. Deciphering the impact of diagenesis overprint on negative δ13C excursions using rock magnetism: Case study of Ediacaran carbonates, Yangjiaping section, South China

    NASA Astrophysics Data System (ADS)

    Macouin, Mélina; Ader, Magali; Moreau, Marie-Gabrielle; Poitou, Charles; Yang, Zhenyu; Sun, Zhimming

    2012-10-01

    Rock magnetism is used here to investigate the genesis of one of the puzzling negative carbon isotopic excursions of the Neoproterozoic in the Yangtze platform (South China). A detailed characterization of the magnetic mineralogy, which includes low-temperature and high-field magnetometry and classical magnetic measurement (ARM, IRM, susceptibility), was therefore performed along upper Doushantuo and lower Dengying Formations outcropping in the Yangjiaping section. The derived magnetic parameters show variations that can be interpreted as variations in magnetic grains size and in oxide contents. They show that the magnetic content is significantly reduced in samples presenting negative δ13Ccalcite values. We interpret this as a result of magnetite dissolution and secondary carbonate precipitation during early diagenesis bacterial sulfate reduction. Combined with C and O isotopic data, paleomagnetic techniques thus show that the upper Doushantuo-lower Dengying negative excursion of the Yangjiaping section is largely due to diagenesis, although the preservation of a genuine δ13C excursion of lower magnitude from +7‰ down to 0‰, instead of down to -9‰ as usually considered, cannot be ruled out. A corrected δ13Ccarbonate chemostratigraphic curve is therefore proposed. The unambiguous identification of a strong diagenetic component for this excursion casts doubts on the primary nature of other potentially time equivalent negative excursions of the Yangtze platform and thus to its correlation to negative excursions in other cratons (i.e. Shuram excursion). More generally, this study illustrates the potential of magnetic mineralogy characterization, a low cost, time efficient and non-destructive technique, as screening tool for diagenetic overprints of δ13C and δ18O.

  19. A self-powered piezoelectric energy harvesting interface circuit with efficiency-enhanced P-SSHI rectifier

    NASA Astrophysics Data System (ADS)

    Liu, Lianxi; Pang, Yanbo; Yuan, Wenzhi; Zhu, Zhangming; Yang, Yintang

    2018-04-01

    The key to self-powered technique is initiative to harvest energy from the surrounding environment. Harvesting energy from an ambient vibration source utilizing piezoelectrics emerged as a popular method. Efficient interface circuits become the main limitations of existing energy harvesting techniques. In this paper, an interface circuit for piezoelectric energy harvesting is presented. An active full bridge rectifier is adopted to improve the power efficiency by reducing the conduction loss on the rectifying path. A parallel synchronized switch harvesting on inductor (P-SSHI) technique is used to improve the power extraction capability from piezoelectric harvester, thereby trying to reach the theoretical maximum output power. An intermittent power management unit (IPMU) and an output capacitor-less low drop regulator (LDO) are also introduced. Active diodes (AD) instead of traditional passive ones are used to reduce the voltage loss over the rectifier, which results in a good power efficiency. The IPMU with hysteresis comparator ensures the interface circuit has a large transient output power by limiting the output voltage ranges from 2.2 to 2 V. The design is fabricated in a SMIC 0.18 μm CMOS technology. Simulation results show that the flipping efficiency of the P-SSHI circuit is over 80% with an off-chip inductor value of 820 μH. The output power the proposed rectifier can obtain is 44.4 μW, which is 6.7× improvement compared to the maximum output power of a traditional rectifier. Both the active diodes and the P-SSHI help to improve the output power of the proposed rectifier. LDO outputs a voltage of 1.8 V with the maximum 90% power efficiency. The proposed P-SSHI rectifier interface circuit can be self-powered without the need for additional power supply. Project supported by the National Natural Science Foundation of China (Nos. 61574103, U1709218) and the Key Research and Development Program of Shaanxi Province (No. 2017ZDXM-GY-006).

  20. Dendron engineering in self-host blue iridium dendrimers towards low-voltage-driving and power-efficient nondoped electrophosphorescent devices.

    PubMed

    Wang, Yang; Wang, Shumeng; Ding, Junqiao; Wang, Lixiang; Jing, Xiabin; Wang, Fosong

    2016-12-20

    Dendron engineering in self-host blue Ir dendrimers is reported to develop power-efficient nondoped electrophosphorescent devices for the first time, which can be operated at low voltage close to the theoretical limit (E g /e: corresponding to the optical bandgap divided by the electron charge). With increasing dendron's HOMO energy levels from B-POCz to B-CzCz and B-CzTA, effective hole injection is favored to promote exciton formation, resulting in a significant reduction of driving voltage and improvement of power efficiency. Consequently, the nondoped device of B-CzTA achieves extremely low driving voltages of 2.7/3.4/4.4 V and record high power efficiencies of 30.3/24.4/16.3 lm W -1 at 1, 100 and 1000 cd m -2 , respectively. We believe that this work will pave the way to the design of novel power-efficient self-host blue phosphorescent dendrimers used for energy-saving displays and solid-state lightings.

  1. Use of an Anatomical Scalar to Control for Sex-Based Size Differences in Measures of Hyoid Excursion during Swallowing

    ERIC Educational Resources Information Center

    Molfenter, Sonja M.; Steele, Catriona M.

    2014-01-01

    Purpose: Traditional methods for measuring hyoid excursion from dynamic videofluoroscopy recordings involve calculating changes in position in absolute units (mm). This method shows a high degree of variability across studies but agreement that greater hyoid excursion occurs inmen than in women. Given that men are typically taller than women, the…

  2. Relation of Phanerozoic stable isotope excursions to climate, bacterial metabolism, and major extinctions

    PubMed Central

    Stanley, Steven M.

    2010-01-01

    Conspicuous global stable carbon isotope excursions that are recorded in marine sedimentary rocks of Phanerozoic age and were associated with major extinctions have generally paralleled global stable oxygen isotope excursions. All of these phenomena are therefore likely to share a common origin through global climate change. Exceptional patterns for carbon isotope excursions resulted from massive carbon burial during warm intervals of widespread marine anoxic conditions. The many carbon isotope excursions that parallel those for oxygen isotopes can to a large degree be accounted for by the Q10 pattern of respiration for bacteria: As temperature changed along continental margins, where ∼90% of marine carbon burial occurs today, rates of remineralization of isotopically light carbon must have changed exponentially. This would have reduced organic carbon burial during global warming and increased it during global cooling. Also contributing to the δ13C excursions have been release and uptake of methane by clathrates, the positive correlation between temperature and degree of fractionation of carbon isotopes by phytoplankton at temperatures below ∼15°, and increased phytoplankton productivity during “icehouse” conditions. The Q10 pattern for bacteria and climate-related changes in clathrate volume represent positive feedbacks for climate change. PMID:21041682

  3. Highway driving safety the day after using sleep medication: the direction of lapses and excursions out-of-lane in drowsy drivers.

    PubMed

    Verster, Joris C; Mooren, Loes; Bervoets, Adriana C; Roth, Thomas

    2017-10-24

    The primary outcome measure of the on-road driving test is the Standard Deviation of Lateral Position. However, other outcome measures, such as lapses and excursions out-of-lane, also need to be considered as they may be related to crash risk. The aim of this study was to determine the direction of lapses and excursions out-of-lane (i.e. towards/into the adjacent traffic lane or towards/into the road shoulder). In total, data from 240 driving tests were re-analysed, and 628 lapses and 401 excursions out-of-lane were identified. The analyses revealed that lapses were made equally frequently over left (49.4%) and over right (43.3%). In contrast, excursions out-of-lane were almost exclusively directed over right into the (safer) road shoulder (97.3%). These findings suggest that drivers are unaware of having lapses, whereas excursions out-of-lane are events where the driver is aware of loss of vehicle control. © 2017 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.

  4. Miniaturized power limiter metasurface based on Fano-type resonance and Babinet principle.

    PubMed

    Loo, Y L; Wang, H G; Zhang, H; Ong, C K

    2016-09-05

    In this work, we present a miniaturize power limiter, a device with size smaller than that required by the working frequency, made of coupled self-complementary electric inductive-capacitive (CELC) resonator and original electric inductive-capacitive (ELC) structure. We also make use of Babinet principle to ensure both CELC and ELC are resonating at the same frequency. The CELC structure is loaded with a Schottky diode to achieve the effect of a nonlinear power limiter. The constructive interference of CELC and ELC structure produces a new Fano-type resonance peak at a lower frequency. The Fano peak is sharp and able to concentrate electric field at a region between the inner and outer metallic patch of the metastructure, hence enhancing the nonlinear properties of the loaded diode. The Fano peak enhances the maximum isolation of the power limiter due to the local field enhancement at where the diode is loaded. Numerical simulation and experiment are conducted in the S-band frequency to verify the power limiting effect of the device designed and to discuss the formation of Fano peak. The power limiter designed has a maximum isolation of 8.4 dB and a 3-dB isolation bandwidth of 6%.

  5. Studies on third-order optical nonlinearity and power limiting of conducting polymers using the z-scan technique for nonlinear optical applications

    NASA Astrophysics Data System (ADS)

    Pramodini, S.; Sudhakar, Y. N.; SelvaKumar, M.; Poornesh, P.

    2014-04-01

    We present the synthesis and characterization of third-order optical nonlinearity and optical limiting of the conducting polymers poly (aniline-co-o-anisidine) and poly (aniline-co-pyrrole). Nonlinear optical studies were carried out by employing the z-scan technique using a He-Ne laser operating in continuous wave mode at 633 nm. The copolymers exhibited a reverse saturable absorption process and self-defocusing properties under the experimental conditions. The estimated values of βeff, n2 and χ(3) were found to be of the order of 10-2 cm W-1, 10-5 esu and 10-7 esu respectively. Self-diffraction rings were observed due to refractive index change when exposed to the laser beam. The copolymers possess a lower limiting threshold and clamping level, which is essential to a great extent for power limiting devices. Therefore, copolymers of aniline emerge as a potential candidate for nonlinear optical device applications.

  6. On-shot characterization of single plasma mirror temporal contrast improvement

    NASA Astrophysics Data System (ADS)

    Obst, L.; Metzkes-Ng, J.; Bock, S.; Cochran, G. E.; Cowan, T. E.; Oksenhendler, T.; Poole, P. L.; Prencipe, I.; Rehwald, M.; Rödel, C.; Schlenvoigt, H.-P.; Schramm, U.; Schumacher, D. W.; Ziegler, T.; Zeil, K.

    2018-05-01

    We report on the setup and commissioning of a compact recollimating single plasma mirror (PM) for temporal contrast enhancement at the Draco 150 TW laser during laser-proton acceleration experiments. The temporal contrast with and without PM is characterized single-shot by means of self-referenced spectral interferometry with extended time excursion at unprecedented dynamic and temporal range. This allows for the first single-shot measurement of the PM trigger point, which is interesting for the quantitative investigation of the complex pre-plasma formation process at the surface of the target used for proton acceleration. As a demonstration of high contrast laser plasma interaction we present proton acceleration results with ultra-thin liquid crystal targets of ∼ 1 μm down to 10 nm thickness. Focus scans of different target thicknesses show that highest proton energies are reached for the thinnest targets at best focus. This indicates that the contrast enhancement is effective such that the acceleration process is not limited by target pre-expansion induced by laser light preceding the main laser pulse.

  7. Off-design temperature effects on nuclear fuel pins for an advanced space-power-reactor concept

    NASA Technical Reports Server (NTRS)

    Bowles, K. J.

    1974-01-01

    An exploratory out-of-reactor investigation was made of the effects of short-time temperature excursions above the nominal operating temperature of 990 C on the compatibility of advanced nuclear space-power reactor fuel pin materials. This information is required for formulating a reliable reactor safety analysis and designing an emergency core cooling system. Simulated uranium mononitride (UN) fuel pins, clad with tungsten-lined T-111 (Ta-8W-2Hf) showed no compatibility problems after heating for 8 hours at 2400 C. At 2520 C and above, reactions occurred in 1 hour or less. Under these conditions free uranium formed, redistributed, and attacked the cladding.

  8. Military Power in Operations Other Than War

    DTIC Science & Technology

    1994-06-03

    of a Shiite state in the south, a Kurdish state in the north, and a Sunni Arab Mesopotamian state in the center, all at war with each other. While...made an excursion into a culture as different from America’s as an African Negro’s is different from that of an Eskimo. No man could hope to span the ...differences in American and Vietnamese culture and heritage in the short time of his appointment in our land. How could I explain . . that while an

  9. Anomalous Dynamical Behavior of Freestanding Graphene Membranes

    NASA Astrophysics Data System (ADS)

    Ackerman, M. L.; Kumar, P.; Neek-Amal, M.; Thibado, P. M.; Peeters, F. M.; Singh, Surendra

    2016-09-01

    We report subnanometer, high-bandwidth measurements of the out-of-plane (vertical) motion of atoms in freestanding graphene using scanning tunneling microscopy. By tracking the vertical position over a long time period, a 1000-fold increase in the ability to measure space-time dynamics of atomically thin membranes is achieved over the current state-of-the-art imaging technologies. We observe that the vertical motion of a graphene membrane exhibits rare long-scale excursions characterized by both anomalous mean-squared displacements and Cauchy-Lorentz power law jump distributions.

  10. Modeling and analysis of several classes of self-oscillating inverters. I - State-plane representations. II - Model extension, classification, and duality relationships

    NASA Technical Reports Server (NTRS)

    Lee, F. C. Y.; Wilson, T. G.

    1982-01-01

    The present investigation is concerned with an important class of power conditioning networks, taking into account self-oscillating dc-to-square-wave transistor inverters. The considered circuits are widely used both as the principal power converting and processing means in many systems and as low-power analog-to-discrete-time converters for controlling the switching of the output-stage semiconductors in a variety of power conditioning systems. Aspects of piecewise-linear modeling are discussed, taking into consideration component models, and an equivalent-circuit model. Questions of singular point analysis and state plane representation are also investigated, giving attention to limit cycles, starting circuits, the region of attraction, a hard oscillator, and a soft oscillator.

  11. A micro-sized bio-solar cell for self-sustaining power generation.

    PubMed

    Lee, Hankeun; Choi, Seokheun

    2015-01-21

    Self-sustainable energy sources are essential for a wide array of wireless applications deployed in remote field locations. Due to their self-assembling and self-repairing properties, "biological solar (bio-solar) cells" are recently gaining attention for those applications. The bio-solar cell can continuously generate electricity from microbial photosynthetic and respiratory activities under day-night cycles. Despite the vast potential and promise of bio-solar cells, they, however, have not yet successfully been translated into commercial applications, as they possess persistent performance limitations and scale-up bottlenecks. Here, we report an entirely self-sustainable and scalable microliter-sized bio-solar cell with significant power enhancement by maximizing solar energy capture, bacterial attachment, and air bubble volume in well-controlled microchambers. The bio-solar cell has a ~300 μL single chamber defined by laser-machined poly(methyl methacrylate) (PMMA) substrates and it uses an air cathode to allow freely available oxygen to act as an electron acceptor. We generated a maximum power density of 0.9 mW m(-2) through photosynthetic reactions of cyanobacteria, Synechocystis sp. PCC 6803, which is the highest power density among all micro-sized bio-solar cells.

  12. Reflective limiters based on self-induced violation of C T symmetry

    NASA Astrophysics Data System (ADS)

    Makri, Eleana; Thomas, Roney; Kottos, Tsampikos

    2018-04-01

    Non-Hermitian bipartite photonic lattices with charge-conjugation (C T ) symmetry can support resonant defect modes which are resilient to bipartite losses and structural imperfections. When, however, a (self-)induced violation of the C T symmetry occurs via tiny permittivity variations, the resonant mode is exposed to the bipartite losses and it is destroyed. Consequently, the transmission peak is suppressed while the reflectance becomes (almost) unity. We propose the use of such photonic systems as power switches, limiters, and sensors.

  13. Ankle Plantarflexor Spasticity Does Not Restrict the Recovery of Ankle Plantarflexor Strength or Ankle Power Generation for Push-Off During Walking Following Traumatic Brain Injury.

    PubMed

    Williams, Gavin; Banky, Megan; Olver, John

    2016-01-01

    The main aim of this project was to determine the impact of plantarflexor spasticity on muscle performance for ambulant people with traumatic brain injury (TBI). A large metropolitan rehabilitation hospital. Seventy-two ambulant people with TBI who were attending physiotherapy for mobility limitations. Twenty-four participants returned for a 6-month follow-up reassessment. Cross-sectional cohort study. Self-selected walking speed, Tardieu scale, ankle plantarflexor strength, and ankle power generation (APG). Participants with ankle plantarflexor spasticity had significantly lower self-selected walking speed; however, there was no significant difference in ankle plantarflexor strength or APG. Participants with ankle plantarflexor spasticity were not restricted in the recovery of self-selected walking speed, ankle plantarflexor strength, or APG, indicating equivalent ability to improve their mobility over time despite the presence of spasticity. Following TBI, people with ankle plantarflexor spasticity have significantly greater mobility limitations than those without spasticity, yet retain the capacity for recovery of self-selected walking speed, ankle plantarflexor strength, and APG.

  14. Modeling the Impact of Forest and Peat Fires on Carbon-Isotopic Compositions of Cretaceous Atmosphere and Vegetation

    NASA Astrophysics Data System (ADS)

    Finkelstein, D. B.; Pratt, L. M.

    2004-12-01

    Prevalence of wildfires or peat fires associated with seasonally dry conditions in the Cretaceous is supported by recent studies documenting the widespread presence of pyrolytic polycyclic aromatic hydrocarbons and fusinite. Potential roles of CO2 emissions from fire have been overlooked in many discussions of Cretaceous carbon-isotope excursions (excluding K-P boundary discussions). Enhanced atmospheric CO2 levels could increase fire frequency through elevated lightning activity. When biomass or peat is combusted, emissions of CO2 are more negative than atmospheric CO2. Five reservoirs (atmosphere, vegetation, soil, and shallow and deep oceans), and five fluxes (productivity, respiration, litter fall, atmosphere-ocean exchange, and surface-deep ocean exchange) were modeled as a closed system. The size of the Cretaceous peat reservoir was estimated by compilation of published early Cretaceous coal resources. Initial pCO2 was assumed to be 2x pre-industrial atmospheric levels (P.A.L.). Critical variables in the model are burning efficiency and post-fire growth rates. Assuming 1% of standing terrestrial biomass is consumed by wildfires each year for ten years (without combustion of peat), an increase of atmospheric CO2 (from 2.0 to 2.2x P.A.L.) and a negative carbon isotope excursion (-1.2 ‰ ) are recorded by both atmosphere and new growth. Net primary productivity linked to the residence time of the vegetation and soil reservoirs results in a negative isotope shift followed by a broad positive isotope excursion. Decreasing the rate of re-growth dampens this trailing positive shift and increases the duration of the excursion. Post-fire pCO2 and new growth returned to initial values after 72 years. Both negative and positive isotope excursions are recorded in the model in surface ocean waters. Exchange of CO2 with the surface- and deep-ocean dampens the isotopic shift of the atmosphere. Excursions are first recorded in the atmosphere (and new growth), followed by the ocean, vegetation, and soil reservoirs. Ten to twenty five-year cycles of drought and fire are not recorded as individual excursions in the soil reservoir as the rate of transfer between the vegetation and soil reservoirs homogenizes the signal. A wildfire-modeled excursion does not propagate a geologically significant excursion through time. Combustion of a peat reservoir is necessary to drive and validate a geologically and isotopically significant excursion. Assuming 0.5% of the standing early Cretaceous peat reservoir is consumed by fire for each year for ten years coupled with the earlier scenario, the atmospheric CO2 increases from 2.0 to 3.1x P.A.L., atmosphere, vegetation, and the surface ocean record a negative carbon isotope excursion of -5.1 ‰ , -3.8 ‰ and -1.8 ‰ respectively, with a duration of 741 years. Increasing the size of the vegetation reservoir translates the excursions from the centennial to millennial scale. For example, doubling the vegetation reservoir (from 1.4 to 2.8E+16 gC) for a 25 year global peat conflagration (0.5% combusted each year) results in a CO2 increase from 2.0 to 4.0x P.A.L., and the atmosphere, vegetation, and the surface ocean reservoirs with a negative carbon isotope excursion of -5.7 ‰ , -8.7 ‰ and -2.3 ‰ respectively. Addition of carbonaceous aerosols (black carbon and polycyclic aromatic hydrocarbons) to pelagic marine sediments could potentially serve as a high-resolution record of ancient fires and firmly tie isotopic shifts to paleofires.

  15. Short Magma Residence Times at Mt. Rainier and the Probable Absence of a Large, Integrated, and Long-lived Magma Reservoir System

    NASA Astrophysics Data System (ADS)

    Sisson, T. W.; Lanphere, M. A.

    2003-12-01

    Intensive, high-precision K-Ar and 40Ar/39Ar geochronology have proven essential for producing modern geologic maps of volcanoes and from these determining the volcanoes' time-volume histories. If sufficiently abundant, these data can also reveal aspects of the magma supply system. For Cascade volcanoes a general result has been the demonstration that edifice growth is highly episodic. Mount Rainier grew in the last 500,000 years atop the remains of an ancestral edifice that was active in the same location 1 - 2 Myr ago. The 500,000 year history of the modern edifice falls into four stages of alternating high and low magmatic output of subequal duration, but major and trace element compositions of eruptives show no correlation with volcano growth stages. Instead, the same spectrum of magmas (andesite to low-Si dacite) erupted throughout the history of the volcano with compositions in the same relative abundances. Superimposed on this seemingly null result are at least 6 brief but pronounced excursions in magma trace-element compositions. Concentrations of Zr, Ba, or Sr can double and then return to background values passing into and out of a single flow or flow-group. Some excursions are tightly bracketed by mapping and by measured ages and have durations no more than the geochronologic measurement precision of about 10,000 years. True excursion durations are potentially much shorter. The brevity and abrupt onsets and cessations of these compositional excursions are evidence against the presence of a sizeable, long-lived magma reservoir anywhere beneath the volcano, including a MASH zone in the lower crust, that would have attenuated, dampened, and homogenized compositional excursions introduced into the magmatic system. Instead, we take 10,000 years as a probable upper limit to the average residence time of magma batches transiting the crustal portion of Mount Rainier's plumbing system. A consistent scenario is that parental magmas enter the crust, differentiate, assimilate, and either erupt or solidify in less than 10,000 years. Geochronologic evidence from much larger magmatic systems (Reid and coworkers, Long Valley, Yellowstone) suggests that more productive systems can have much longer average residence times than modestly active arc stratovolcanoes like Mt. Rainier.

  16. Multiple-time-scale motion in molecularly linked nanoparticle arrays.

    PubMed

    George, Christopher; Szleifer, Igal; Ratner, Mark

    2013-01-22

    We explore the transport of electrons between electrodes that encase a two-dimensional array of metallic quantum dots linked by molecular bridges (such as α,ω alkaline dithiols). Because the molecules can move at finite temperatures, the entire transport structure comprising the quantum dots and the molecules is in dynamical motion while the charge is being transported. There are then several physical processes (physical excursions of molecules and quantum dots, electronic migration, ordinary vibrations), all of which influence electronic transport. Each can occur on a different time scale. It is therefore not appropriate to use standard approaches to this sort of electron transfer problem. Instead, we present a treatment in which three different theoretical approaches-kinetic Monte Carlo, classical molecular dynamics, and quantum transport-are all employed. In certain limits, some of the dynamical effects are unimportant. But in general, the transport seems to follow a sort of dynamic bond percolation picture, an approach originally introduced as formal models and later applied to polymer electrolytes. Different rate-determining steps occur in different limits. This approach offers a powerful scheme for dealing with multiple time scale transport problems, as will exist in many situations with several pathways through molecular arrays or even individual molecules that are dynamically disordered.

  17. Assessment of vertical excursions and open-sea psychological performance at depths to 250 fsw.

    PubMed

    Miller, J W; Bachrach, A J; Walsh, J M

    1976-12-01

    A series of 10 two-man descending vertical excursion dives was carried out in the open sea from an ocean-floor habitat off the coast of Puerto Rico by four aquanauts saturated on a normoxic-nitrogen breathing mixture at a depth of 106 fsw. The purpose of these dives was two-fold: to validate laboratory findings with respect to decompression schedules and to determine whether such excursions would produce evidence of adaptation to nitrogen narcosis. For the latter, tests designed to measure time estimation, short-term memory, and auditory vigilance were used. The validation of experimental excursion tables was carried out without incidence of decompression sickness. Although no signs of nitrogen narcosis were noted during testing, all subjects made significantly longer time estimates in the habitat and during the excursions than on the surface. Variability and incomplete data prevented a statistical analysis of the short-term memory results, and the auditory vigilance proved unusable in the water.

  18. Human risk factors associated with pilots in runway excursions.

    PubMed

    Chang, Yu-Hern; Yang, Hui-Hua; Hsiao, Yu-Jung

    2016-09-01

    A breakdown analysis of civil aviation accidents worldwide indicates that the occurrence of runway excursions represents the largest portion among all aviation occurrence categories. This study examines the human risk factors associated with pilots in runway excursions, by applying a SHELLO model to categorize the human risk factors and to evaluate the importance based on the opinions of 145 airline pilots. This study integrates aviation management level expert opinions on relative weighting and improvement-achievability in order to develop four kinds of priority risk management strategies for airline pilots to reduce runway excursions. The empirical study based on experts' evaluation suggests that the most important dimension is the liveware/pilot's core ability. From the perspective of front-line pilots, the most important risk factors are the environment, wet/containment runways, and weather issues like rain/thunderstorms. Finally, this study develops practical strategies for helping management authorities to improve major operational and managerial weaknesses so as to reduce the human risks related to runway excursions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. The metatarsosesamoid joint: an in vitro 3D quantitative assessment.

    PubMed

    Jamal, Bilal; Pillai, Anand; Fogg, Quentin; Kumar, Senthil

    2015-03-01

    The anatomy of the first metatarsophalangeal (MTP) joint, particularly the metatarsosesamoid articulation, remains poorly understood. Our goal was to quantitatively define the excursion of the sesamoids. Seven cadavers were dissected to assess the articulating surfaces throughout a normal range of motion. The dissections were digitally reconstructed in various positions using a MicroScribe. For first MTP joint, excursion averaged 14.7mm for the tibial sesamoid in the sagittal plane and 7.5mm for the fibular sesamoid. The sesamoids also moved medially to laterally when the joint was dorsiflexed. For the maximally dorsiflexed joint, excursion averaged 2.8mm for the tibial sesamoid and 3.5mm for the fibular sesamoid. Hallucal sesamoids appear to have differential tracking: the tibial sesamoid has greater longitudinal excursion; the fibular sesamoid has greater lateral excursion. The anatomical data will interest those involved with the design of an effective hallux arthroplasty. Copyright © 2014 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  20. Geomagnetic field excursion recorded 17 ka at Tianchi Volcano, China: New 40Ar/39Ar age and significance

    NASA Astrophysics Data System (ADS)

    Singer, Brad S.; Jicha, Brian R.; He, Huaiyu; Zhu, Rixiang

    2014-04-01

    New 40Ar/39Ar dating of a comenditic lava atop Tianchi Volcano, China, indicates eruption at 17.1 ± 0.9 ka. The flow interior records a pair of transitional virtual geomagnetic poles and a low paleointensity of ~25 μT. Thus, it records a geomagnetic field excursion that is younger than the 41 ka Laschamp or 32 ka Auckland excursions. Implications are: (1) following a repose of several tens of kyr, Tianchi Volcano became highly active immediately following termination of the last glaciation maximum. The flare-up of silicic eruptions may reflect rapid deglaciation of the edifice. (2) A 17 ka age for the Tianchi excursion provides the first direct radioisotopic evidence that excursional behavior, which is imprecisely dated and less well documented magnetically at several other sites, is a global feature of geodynamo behavior. (3) During the Brunhes chron, 13 well-dated excursions cluster into two periods, including seven between 17 and 212 ka, and six between about 530 and 730 ka.

  1. A self-powered, one-step chip for rapid, quantitative and multiplexed detection of proteins from pinpricks of whole blood.

    PubMed

    Wang, Jun; Ahmad, Habib; Ma, Chao; Shi, Qihui; Vermesh, Ophir; Vermesh, Udi; Heath, James

    2010-11-21

    We describe an automated, self-powered chip based on lateral flow immunoassay for rapid, quantitative, and multiplex protein detection from pinpricks of whole blood. The device incorporates on-chip purification of blood plasma by employing inertial forces to focus blood cells away from the assay surface, where plasma proteins are captured and detected on antibody "barcode" arrays. Power is supplied from the capillary action of a piece of adsorbent paper, and sequentially drives, over a 40 minute period, the four steps required to capture serum proteins and then develop a multiplex immunoassay. An 11 protein panel is assayed from whole blood, with high sensitivity and high reproducibility. This inexpensive, self-contained, and easy to operate chip provides a useful platform for point-of-care diagnoses, particularly in resource-limited settings.

  2. Analysis and Forecasting of Shoreline Position

    NASA Astrophysics Data System (ADS)

    Barton, C. C.; Tebbens, S. F.

    2007-12-01

    Analysis of historical shoreline positions on sandy coasts, in the geologic record, and study of sea-level rise curves reveals that the dynamics of the underlying processes produce temporal/spatial signals that exhibit power scaling and are therefore self-affine fractals. Self-affine time series signals can be quantified over many orders of magnitude in time and space in terms of persistence, a measure of the degree of correlation between adjacent values in the stochastic portion of a time series. Fractal statistics developed for self-affine time series are used to forecast a probability envelope bounding future shoreline positions. The envelope provides the standard deviation as a function of three variables: persistence, a constant equal to the value of the power spectral density when 1/period equals 1, and the number of time increments. The persistence of a twenty-year time series of the mean-high-water (MHW) shoreline positions was measured for four profiles surveyed at Duck, NC at the Field Research Facility (FRF) by the U.S. Army Corps of Engineers. The four MHW shoreline time series signals are self-affine with persistence ranging between 0.8 and 0.9, which indicates that the shoreline position time series is weakly persistent (where zero is uncorrelated), and has highly varying trends for all time intervals sampled. Forecasts of a probability envelope for future MHW positions are made for the 20 years of record and beyond to 50 years from the start of the data records. The forecasts describe the twenty-year data sets well and indicate that within a 96% confidence envelope, future decadal MHW shoreline excursions should be within 14.6 m of the position at the start of data collection. This is a stable-oscillatory shoreline. The forecasting method introduced here includes the stochastic portion of the time series while the traditional method of predicting shoreline change reduces the time series to a linear trend line fit to historic shoreline positions and extrapolated linearly to forecast future positions with a linearly increasing mean that breaks the confidence envelope eight years into the future and continues to increase. The traditional method is a poor representation of the observed shoreline position time series and is a poor basis for extrapolating future shoreline positions.

  3. Head Excursion of Restrained Human Volunteers and Hybrid III Dummies in Steady State Rollover Tests

    PubMed Central

    Moffatt, Edward; Hare, Barry; Hughes, Raymond; Lewis, Lance; Iiyama, Hiroshi; Curzon, Anne; Cooper, Eddie

    2003-01-01

    Seatbelts provide substantial benefits in rollover crashes, yet occupants still receive head and neck injuries from contacting the vehicle roof interior when the roof exterior strikes the ground. Prior research has evaluated rollover restraint performance utilizing anthropomorphic test devices (dummies), but little dynamic testing has been done with human volunteers to learn how they move during rollovers. In this study, the vertical excursion of the head of restrained dummies and human subjects was measured in a vehicle being rotated about its longitudinal roll axis at roll rates from 180-to-360 deg/sec and under static inversion conditions. The vehicle’s restraint design was the commonly used 3-point seatbelt with continuous loop webbing and a sliding latch plate. This paper presents an analysis of the observed occupant motion and provides a comparison of dummy and human motion under similar test conditions. Thirty-five tests (eighteen static and seventeen dynamic) were completed using two different sizes of dummies and human subjects in both near and far-side roll directions. The research indicates that far-side rollovers cause the restrained test subjects to have greater head excursion than near-side rollovers, and that static inversion testing underestimates head excursion for far-side occupants. Human vertical head excursion of up to 200 mm was found at a roll rate of 220 deg/sec. Humans exhibit greater variability in head excursion in comparison to dummies. Transfer of seatbelt webbing through the latch plate did not correlate directly with differences in head excursion. PMID:12941241

  4. Record of the Late Devonian Hangenberg global positive carbon-isotope excursion in an epeiric sea setting: Carbonate production, organic-carbon burial and paleoceanography during the late Famennian

    USGS Publications Warehouse

    Cramer, Bradley D.; Saltzman, Matthew R.; Day, J.E.; Witzke, B.J.

    2008-01-01

    Latest Famennian marine carbonates from the mid-continent of North America were examined to investigate the Late Devonian (very late Famennian) Hangenberg positive carbon-isotope (??13 Ccarb) excursion. This global shift in the ?? 13C of marine waters began during the late Famennian Hangenberg Extinction Event that occurred during the Middle Siphonodella praesulcata conodont zone. The post-extinction recovery interval spans the Upper S. praesulcata Zone immediately below the Devonian-Carboniferous boundary. Positive excursions in ?? 13 Ccarb are often attributed to the widespread deposition of organic-rich black shales in epeiric sea settings. The Hangenberg ??13 Ccarb excursion documented in the Louisiana Limestone in this study shows the opposite trend, with peak ??13 Ccarb values corresponding to carbonate production in the U.S. mid-continent during the highstand phase of the very late Famennian post-glacial sea level rise. Our data indicate that the interval of widespread black shale deposition (Hangenberg Black Shale) predates the peak isotope values of the Hangenberg ??13 Ccarb excursion and that peak values of the Hangenberg excursion in Missouri are not coincident with and cannot be accounted for by high Corg burial in epeiric seas. We suggest instead that sequestration and burial of Corg in the deep oceans drove the peak interval of the ??13Ccarb excursion, as a result of a change in the site of deep water formation to low-latitude epeiric seas as the global climate shifted between cold and warm states.

  5. A paleomagnetic record in loess-paleosol sequences since late Pleistocene in the arid Central Asia

    NASA Astrophysics Data System (ADS)

    Li, Guanhua; Xia, Dunsheng; Appel, Erwin; Wang, Youjun; Jia, Jia; Yang, Xiaoqiang

    2018-03-01

    Geomagnetic excursions during Brunhes epoch have been brought to the forefront topic in paleomagnetic study, as they provide key information about Earth's interior dynamics and could serve as another tool for stratigraphic correlation among different lithology. Loess-paleosol sequences provide good archives for decoding geomagnetic excursions. However, the detailed pattern of these excursions was not sufficiently clarified due to pedogenic influence. In this study, paleomagnetic analysis was performed in loess-paleosol sequences on the northern piedmont of the Tianshan Mountains (northwestern China). By radiocarbon and luminance dating, the loess section was chronologically constrained to mainly the last c.130 ka, a period when several distinct geomagnetic excursions were involved. The rock magnetic properties in this loess section are dominated by magnetite and maghemite in a pseudo-single-domain state. The rock magnetic properties and magnetic anisotropy indicate weakly pedogenic influence for magnetic record. The stable component of remanent magnetization derived from thermal demagnetization revealed the presence of two intervals of directional anomalies with corresponding intensity lows in the Brunhes epoch. The age control in the key layers indicates these anomalies are likely associated with the Laschamp and Blake excursions, respectively. In addition, relative paleointensity in the loess section is basically compatible with other regional and global relative paleointensity records and indicates two low-paleointensity zones, possibly corresponding to the Blake and Laschamp excursions, respectively. As a result, this study suggests that the loess section may have the potential to record short-lived excursions, which largely reflect the variation of dipole components in the global archives.

  6. Engaging students in research learning experiences through hydrology field excursions and projects

    NASA Astrophysics Data System (ADS)

    Ewen, T.; Seibert, J.

    2014-12-01

    One of the best ways to engage students and instill enthusiasm for hydrology is to expose them to hands-on learning. A focus on hydrology field research can be used to develop context-rich and active learning, and help solidify idealized learning where students are introduced to individual processes through textbook examples, often neglecting process interactions and an appreciation for the complexity of the system. We introduced a field course where hydrological measurement techniques are used to study processes such as snow hydrology and runoff generation, while also introducing students to field research and design of their own field project. In the field projects, students design a low-budget experiment with the aim of going through the different steps of a 'real' scientific project, from formulating the research question to presenting their results. In one of the field excursions, students make discharge measurements in several alpine streams with a salt tracer to better understand the spatial characteristics of an alpine catchment, where source waters originate and how they contribute to runoff generation. Soil moisture measurements taken by students in this field excursion were used to analyze spatial soil moisture patterns in the alpine catchment and subsequently used in a publication. Another field excursion repeats a published experiment, where preferential soil flow paths are studied using a tracer and compared to previously collected data. For each field excursion, observational data collected by the students is uploaded to an online database we developed, which also allows students to retrieve data from past excursions to further analyze and compare their data. At each of the field sites, weather stations were installed and a webviewer allows access to realtime data from data loggers, allowing students to explore how processes relate to climatic conditions. With in-house film expertise, these field excursions were also filmed and short virtual excursions were produced, which we plan to use in a large introductory course, exposing students to field research at an early stage.

  7. 47 CFR 20.21 - Signal boosters.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... operation to ensure compliance with applicable noise and gain limits and either self-correct or shut down... provide equivalent uplink and downlink gain and conducted uplink power output that is at least 0.05 watts... referenced to the booster's input port for each band of operation. (C) Booster Gain Limits. (1) The uplink...

  8. 47 CFR 20.21 - Signal boosters.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... operation to ensure compliance with applicable noise and gain limits and either self-correct or shut down... provide equivalent uplink and downlink gain and conducted uplink power output that is at least 0.05 watts... referenced to the booster's input port for each band of operation. (C) Booster Gain Limits. (1) The uplink...

  9. Ultra-rapid BioChaperone Lispro Improves post-prandial Blood Glucose Excursions versus Insulin Lispro in a 14-day crossover Treatment Study in Patients with Type 1 Diabetes.

    PubMed

    Andersen, Grit; Meiffren, Grégory; Lamers, Daniela; DeVries, J Hans; Ranson, Aymeric; Seroussi, Cyril; Alluis, Bertrand; Gaudier, Martin; Soula, Olivier; Heise, Tim

    2018-06-19

    To investigate safety and efficacy of BioChaperone insulin lispro (BCLIS), an ultra-rapid formulation of insulin lispro (LIS) in patients with type 1 diabetes. In this randomized, double-blind study, patients self-administered individualized bolus doses of BCLIS or LIS during two 14-day periods in a crossover fashion. Postprandial blood glucose (PPG) was assessed following individualized solid mixed meal tests (MMT) (50% carbs, 29% fat, 21% proteins) with additional randomization for the sequence of timing of insulin administration, immediately (t0), 15 minutes before (t-15) and 15 minutes after (t+15) meal start on days 1, 2 and 3 and with t0 administration on day 14. Pharmacokinetics (PK) were assessed for t0 MMTs. Patients also used individualized BCLIS or LIS doses immediately before meals during two 10-day outpatient periods with unchanged basal insulin regimen. Overall, 35 patients completed both treatment periods. In MMTs with t0 administration, the higher early postprandial PK exposure of BCLIS led to significant reductions in 1-2 hr PPG excursions by 30-40% vs LIS and the accelerated absorption and action of BCLIS persisted over 14 days. There was no difference in glucose excursion over the full 360 min postprandial period. PPG control was similar between BCLIS injected at t+15 and LIS at t0. BCLIS demonstrated safety and tolerability comparable to LIS. No injection site reactions occurred with BCLIS. BCLIS was well-tolerated and safe over 14 days of treatment and significantly improved PPG versus LIS when administered at mealtime. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  10. The dominance behavioral system and manic temperament: Motivation for dominance, self-perceptions of power, and socially dominant behaviors

    PubMed Central

    Johnson, Sheri L.; Carver, Charles S.

    2013-01-01

    The dominance behavioral system has been conceptualized as a biologically based system comprising motivation to achieve social power and self-perceptions of power. Biological, behavioral, and social correlates of dominance motivation and self-perceived power have been related to a range of psychopathological tendencies. Preliminary evidence suggests that mania and risk for mania (manic temperament) relate to the dominance system. Method Four studies examine whether manic temperament, measured with the Hypomanic Personality Scale (HPS), is related to elevations in dominance motivation, self-perceptions of power, and engagement in socially dominant behavior across multiple measures. In Study 1, the HPS correlated with measures of dominance motivation and the pursuit of extrinsically-oriented ambitions for fame and wealth among 454 undergraduates. In Study 2, the HPS correlated with perceptions of power and extrinsically-oriented lifetime ambitions among 780 undergraduates. In Study 3, the HPS was related to trait-like tendencies to experience hubristic (dominance-related) pride, as well as dominance motivation and pursuit of extrinsically-oriented ambitions. In Study 4, we developed the Socially Dominant Behavior Scale to capture behaviors reflecting high power. The scale correlated highly with the HPS among 514 undergraduates. Limitations The studies rely on self-ratings of manic temperament and dominance constructs, and findings have not yet been generalized to a clinical sample. Conclusions Taken together, results support the hypothesis that manic temperament is related to a focus on achieving social dominance, ambitions related to achieving social recognition, perceptions of having achieved power, tendencies to experience dominance-related pride, and engagement in social behaviors consistent with this elevated sense of power. PMID:22840614

  11. Transient and Steady-state Tests of the Space Power Research Engine with Resistive and Motor Loads

    NASA Technical Reports Server (NTRS)

    Rauch, Jeffrey S.; Kankam, M. David

    1995-01-01

    The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

  12. Transient and steady-state tests of the space power research engine with resistive and motor loads

    NASA Astrophysics Data System (ADS)

    Rauch, Jeffrey S.; Kankam, M. David

    1995-01-01

    The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

  13. Effect of self-organized interdependence between populations on the evolution of cooperation

    NASA Astrophysics Data System (ADS)

    Luo, Chao; Zhang, Xiaolin

    2017-01-01

    In this article, based on interdependent networks, the effect of self-organized interdependence on the evolution of cooperation is studied. Different from the previous works, the interdependent strength, which can effectively improve the fitness of players, is taken as a kind of limited resources and co-evolves with players' strategy. We show that the self-organization of interdependent strength would spontaneously lead to power law distribution at the stationary state, where the level of cooperation in system can be significantly promoted. Furthermore, when intermediate quantity of interdependence resources existing in system, the power law distribution is most evident with the power β ≈ 1.72, meanwhile the level of cooperation also reaches the maximum value. We discuss the related microscopic system properties which are responsible for the observed results and also demonstrate that the power law distribution of interdependence resources is an elementary property which is robust against the governing repeated games and the initial resources allocation patterns.

  14. Video game-based exercises for balance rehabilitation: a single-subject design.

    PubMed

    Betker, Aimee L; Szturm, Tony; Moussavi, Zahra K; Nett, Cristabel

    2006-08-01

    To investigate whether coupling foot center of pressure (COP)-controlled video games to standing balance exercises will improve dynamic balance control and to determine whether the motivational and challenging aspects of the video games would increase a subject's desire to perform the exercises and complete the rehabilitation process. Case study, pre- and postexercise. University hospital outpatient clinic. A young adult with excised cerebellar tumor, 1 middle-aged adult with single right cerebrovascular accident, and 1 middle-aged adult with traumatic brain injury. A COP-controlled, video game-based exercise system. The following were calculated during 12 different tasks: the number of falls, range of COP excursion, and COP path length. Postexercise, subjects exhibited a lower fall count, decreased COP excursion limits for some tasks, increased practice volume, and increased attention span during training. The COP-controlled video game-based exercise regime motivated subjects to increase their practice volume and attention span during training. This in turn improved subjects' dynamic balance control.

  15. Temperature-Controlled Clamping and Releasing Mechanism

    NASA Technical Reports Server (NTRS)

    Rosing, David; Ford, Virginia

    2005-01-01

    A report describes the development of a mechanism that automatically clamps upon warming and releases upon cooling between temperature limits of approx. =180 K and approx. =293 K. The mechanism satisfied a need specific to a program that involved repeated excursions of a spectrometer between a room-temperature atmospheric environment and a cryogenic vacuum testing environment. The mechanism was also to be utilized in the intended application of the spectrometer, in which the spectrometer would be clamped for protection during launch of a spacecraft and released in the cold of outer space to allow it to assume its nominal configuration for scientific observations. The mechanism is passive in the sense that its operation does not depend on a control system and does not require any power other than that incidental to heating and cooling. The clamping and releasing action is effected by bolt-preloaded stacks of shape-memory-alloy (SMA) cylinders. In designing this mechanism, as in designing other, similar SMA mechanisms, it was necessary to account for the complex interplay among thermal expansion, elastic and inelastic deformation under load, and SMA thermomechanical properties.

  16. STV engine design considerations

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The topics covered include the following: (1) engine design criteria and issues; (2) design requirements for man rating; (3) test requirements for man rating; (4) design requirements for space basing; (5) engine operation requirements; (6) health monitoring; (7) lunar transfer vehicle (LTV) feed system; (8) lunar excursion vehicle (LEV) propellant system; (9) area ratio gimbal angle limits; (10) reaction control system; and (11) engine configuration and characteristics. This document is presented in viewgraph form.

  17. A self-tuning automatic voltage regulator designed for an industrial environment

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

    Flynn, D.; Hogg, B.W.; Swidenbank, E.

    Examination of the performance of fixed parameter controllers has resulted in the development of self-tuning strategies for excitation control of turbogenerator systems. In conjunction with the advanced control algorithms, sophisticated measurement techniques have previously been adopted on micromachine systems to provide generator terminal quantities. In power stations, however, a minimalist hardware arrangement would be selected leading to relatively simple measurement techniques. The performance of a range of self-tuning schemes is investigated on an industrial test-bed, employing a typical industrial hardware measurement system. Individual controllers are implemented on a standard digital automatic voltage regulator, as installed in power stations. This employsmore » a VME platform, and the self-tuning algorithms are introduced by linking to a transputer network. The AVR includes all normal features, such as field forcing, VAR limiting and overflux protection. Self-tuning controller performance is compared with that of a fixed gain digital AVR.« less

  18. Active transport improves the precision of linear long distance molecular signalling

    NASA Astrophysics Data System (ADS)

    Godec, Aljaž; Metzler, Ralf

    2016-09-01

    Molecular signalling in living cells occurs at low copy numbers and is thereby inherently limited by the noise imposed by thermal diffusion. The precision at which biochemical receptors can count signalling molecules is intimately related to the noise correlation time. In addition to passive thermal diffusion, messenger RNA and vesicle-engulfed signalling molecules can transiently bind to molecular motors and are actively transported across biological cells. Active transport is most beneficial when trafficking occurs over large distances, for instance up to the order of 1 metre in neurons. Here we explain how intermittent active transport allows for faster equilibration upon a change in concentration triggered by biochemical stimuli. Moreover, we show how intermittent active excursions induce qualitative changes in the noise in effectively one-dimensional systems such as dendrites. Thereby they allow for significantly improved signalling precision in the sense of a smaller relative deviation in the concentration read-out by the receptor. On the basis of linear response theory we derive the exact mean field precision limit for counting actively transported molecules. We explain how intermittent active excursions disrupt the recurrence in the molecular motion, thereby facilitating improved signalling accuracy. Our results provide a deeper understanding of how recurrence affects molecular signalling precision in biological cells and novel medical-diagnostic devices.

  19. Evaluation of dynamic balance among community-dwelling older adult fallers: a generalizability study of the limits of stability test.

    PubMed

    Clark, S; Rose, D J

    2001-04-01

    To establish reliability estimates of the 75% Limits of Stability Test (75% LOS test) when administered to community-dwelling older adults with a history of falls. Generalizability theory was used to estimate both the relative contribution of identified error sources to the total measurement error and generalizability coefficients. A random effects repeated-measures analysis of variance (ANOVA) was used to assess consistency of LOS test movement variables across both days and targets. A motor control research laboratory in a university setting. Fifty community-dwelling older adults with 2 or more falls in the previous year. Spatial and temporal measures of dynamic balance derived from the 75% LOS test included average movement velocity, maximum center of gravity (COG) excursion, end-point COG excursion, and directional control. Estimated generalizability coefficients for 2 testing days ranged from.58 to.87. Total variance in LOS test measures attributable to inconsistencies in day-to-day test performance (Day and Subject x Day facets) ranged from 2.5% to 8.4%. The ANOVA results indicated that no significant differences were observed in the LOS test variables across the 2 testing days. The 75% LOS test administered to older adult fallers on 2 consecutive days provides consistent and reliable measures of dynamic balance.

  20. Evaluating OSHA's ethylene oxide standard: employer exposure-monitoring activities in Massachusetts hospitals from 1985 through 1993.

    PubMed Central

    LaMontagne, A D; Kelsey, K T

    1997-01-01

    OBJECTIVES: This study characterized exposure-monitoring activities and findings under the Occupational Safety and Health Administration's (OSHA's) 1984 ethylene oxide (EtO) standard. METHODS: In-depth mail and telephone surveys were followed by on-site interviews at all EtO-using hospitals in Massachusetts (n = 92, 96% participation rate). RESULTS: By 1993, most hospitals had performed personal exposure monitoring for OSHA's 8-hour action level (95%) and the excursion limit (87%), although most did not meet the 1985 implementation deadline. In 1993, 66% of hospitals reported the installation of EtO alarms to fulfill the standard's "alert" requirement. Alarm installation also lagged behind the 1985 deadline and peaked following a series of EtO citations by OSHA. From 1990 through 1992, 23% of hospitals reported having exceeded the action level once or more; 24% reported having exceeded the excursion limit; and 33% reported that workers were accidentally exposed to EtO in the absence of personal monitoring. CONCLUSIONS: Almost a decade after passage of the EtO standard, exposure-monitoring requirements were widely, but not completely, implemented. Work-shift exposures had markedly decreased since the mid-1980s, but overexposures continued to occur widely. OSHA enforcement appears to have stimulated implementation. PMID:9240100

  1. Influx of Dissolved Silica in Shallow Marine Environments in the Early Rhaetian (Late Triassic): Implications for Timing of Supercontinental Rifting

    NASA Astrophysics Data System (ADS)

    Tackett, L.

    2017-12-01

    The Rhaetian Stage of the Late Triassic terminated with a mass extinction, but the late Norian-early Rhaetian paleoecological and geochemical transitions and their relationship to events leading up to the End-Triassic mass extinction are poorly understood. To address this issue, presented here is a multi-proxy dataset from New York Canyon, Nevada (USA) relating isotope chemostratigraphy (Sr, C, O), shallow marine benthic macrofossils, and microfossils. At this Panthalassan locality the Norian-Rhaetian boundary is characterized by a negative strontium isotope excursion that facilitates correlation with Tethyan deposits. In sedimentary horizons immediately below and above this excursion, siliceous demosponge spicules (desmids) are abundant components of the microfossil populations, and silicification of calcareous microfossils becomes common. In the sedimentary beds marking the main excursion, hexactinellid sponge spicules are abundant. These results indicate a large input of dissolved silica in shallow marine environments, while the negative strontium values are consistent with increased seafloor spreading and hydrothermal vent activity or basalt weathering, either scenario being a plausible silica source for the typically silica-limited sponges that proliferated during this interval. The biosedimentary features observed across the Norian-Rhaetian boundary are similar to those observed in the earliest Jurassic in marine sections around the world following the End-Triassic mass extinction, but no clear biotic turnover is observed across the Norian-Rhaetian boundary in this succession. Thus, biosedimentary shifts across the Norian-Rhaetian boundary may add important geochemical context to the end-Triassic mass extinction event.

  2. Glucose excursions and glycaemic control during Ramadan fasting in diabetic patients: insights from continuous glucose monitoring (CGM).

    PubMed

    Lessan, N; Hannoun, Z; Hasan, H; Barakat, M T

    2015-02-01

    Ramadan fasting represents a major shift in meal timing and content for practicing Muslims. This study used continuous glucose monitoring (CGM) to assess changes in markers of glycaemic excursions during Ramadan fasting to investigate the short-term safety of this practice in different groups of patients with diabetes. A total of 63 subjects (56 with diabetes, seven healthy volunteers; 39 male, 24 female) had CGM performed during, before and after Ramadan fasting. Mean CGM curves were constructed for each group for these periods that were then used to calculate indicators of glucose control and excursions. Post hoc data analyses included comparisons of different medication categories (metformin/no medication, gliptin, sulphonylurea and insulin). Medication changes during Ramadan followed American Diabetes Association guidelines. Among patients with diabetes, there was a significant difference in mean CGM curve during Ramadan, with a slow fall during fasting hours followed by a rapid rise in glucose level after the sunset meal (iftar). The magnitude of this excursion was greatest in the insulin-treated group, followed by the sulphonylurea-treated group. Markers of control deteriorated in a small number (n=3) of patients. Overall, whether fasting or non-fasting, subjects showed no statistically significant changes in mean interstitial glucose (IG), mean amplitude of glycaemic excursion (MAGE), high and low blood glucose indices (HBGI/LBGI), and number of glucose excursions and rate of hypoglycaemia. The main change in glycaemic control with Ramadan fasting in patients with diabetes is in the pattern of excursions. Ramadan fasting caused neither overall deterioration nor improvement in the majority of patients with good baseline glucose control. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  3. Comparison of Diaphragmatic Breathing Exercise, Volume and Flow Incentive Spirometry, on Diaphragm Excursion and Pulmonary Function in Patients Undergoing Laparoscopic Surgery: A Randomized Controlled Trial

    PubMed Central

    Anand, R.

    2016-01-01

    Objective. To evaluate the effects of diaphragmatic breathing exercises and flow and volume-oriented incentive spirometry on pulmonary function and diaphragm excursion in patients undergoing laparoscopic abdominal surgery. Methodology. We selected 260 patients posted for laparoscopic abdominal surgery and they were block randomization as follows: 65 patients performed diaphragmatic breathing exercises, 65 patients performed flow incentive spirometry, 65 patients performed volume incentive spirometry, and 65 patients participated as a control group. All of them underwent evaluation of pulmonary function with measurement of Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Peak Expiratory Flow Rate (PEFR), and diaphragm excursion measurement by ultrasonography before the operation and on the first and second postoperative days. With the level of significance set at p < 0.05. Results. Pulmonary function and diaphragm excursion showed a significant decrease on the first postoperative day in all four groups (p < 0.001) but was evident more in the control group than in the experimental groups. On the second postoperative day pulmonary function (Forced Vital Capacity) and diaphragm excursion were found to be better preserved in volume incentive spirometry and diaphragmatic breathing exercise group than in the flow incentive spirometry group and the control group. Pulmonary function (Forced Vital Capacity) and diaphragm excursion showed statistically significant differences between volume incentive spirometry and diaphragmatic breathing exercise group (p < 0.05) as compared to that flow incentive spirometry group and the control group. Conclusion. Volume incentive spirometry and diaphragmatic breathing exercise can be recommended as an intervention for all patients pre- and postoperatively, over flow-oriented incentive spirometry for the generation and sustenance of pulmonary function and diaphragm excursion in the management of laparoscopic abdominal surgery. PMID:27525116

  4. Comparison of Diaphragmatic Breathing Exercise, Volume and Flow Incentive Spirometry, on Diaphragm Excursion and Pulmonary Function in Patients Undergoing Laparoscopic Surgery: A Randomized Controlled Trial.

    PubMed

    Alaparthi, Gopala Krishna; Augustine, Alfred Joseph; Anand, R; Mahale, Ajith

    2016-01-01

    Objective. To evaluate the effects of diaphragmatic breathing exercises and flow and volume-oriented incentive spirometry on pulmonary function and diaphragm excursion in patients undergoing laparoscopic abdominal surgery. Methodology. We selected 260 patients posted for laparoscopic abdominal surgery and they were block randomization as follows: 65 patients performed diaphragmatic breathing exercises, 65 patients performed flow incentive spirometry, 65 patients performed volume incentive spirometry, and 65 patients participated as a control group. All of them underwent evaluation of pulmonary function with measurement of Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Peak Expiratory Flow Rate (PEFR), and diaphragm excursion measurement by ultrasonography before the operation and on the first and second postoperative days. With the level of significance set at p < 0.05. Results. Pulmonary function and diaphragm excursion showed a significant decrease on the first postoperative day in all four groups (p < 0.001) but was evident more in the control group than in the experimental groups. On the second postoperative day pulmonary function (Forced Vital Capacity) and diaphragm excursion were found to be better preserved in volume incentive spirometry and diaphragmatic breathing exercise group than in the flow incentive spirometry group and the control group. Pulmonary function (Forced Vital Capacity) and diaphragm excursion showed statistically significant differences between volume incentive spirometry and diaphragmatic breathing exercise group (p < 0.05) as compared to that flow incentive spirometry group and the control group. Conclusion. Volume incentive spirometry and diaphragmatic breathing exercise can be recommended as an intervention for all patients pre- and postoperatively, over flow-oriented incentive spirometry for the generation and sustenance of pulmonary function and diaphragm excursion in the management of laparoscopic abdominal surgery.

  5. A carbon isotopic and sedimentological record of the latest Devonian (Famennian) from the Western U.S. and Germany

    USGS Publications Warehouse

    Myrow, P.M.; Strauss, J.V.; Creveling, J.R.; Sicard, K.R.; Ripperdan, R.; Sandberg, C.A.; Hartenfels, S.

    2011-01-01

    New carbon isotopic data from upper Famennian deposits in the western United States reveal two previously unrecognized major positive isotopic excursions. The first is an abrupt ~. 3??? positive excursion, herein referred to as ALFIE (A Late Famennian Isotopic Excursion), recorded in two sections of the Pinyon Peak Limestone of north-central Utah. Integration of detailed chemostratigraphic and biostratigraphic data suggests that ALFIE is the Laurentian record of the Dasberg Event, which has been linked to transgression in Europe and Morocco. Sedimentological data from the Chaffee Group of western Colorado also record transgression at a similar biostratigraphic position, with a shift from restricted to open-marine lithofacies. ALFIE is not evident in chemostratigraphic data from age-equivalent strata in Germany studied herein and in southern Europe, either because it is a uniquely North American phenomenon, or because the German sections are too condensed relative to those in Laurentia. A second positive carbon isotopic excursion from the upper Chaffee Group of Colorado is recorded in transgressive strata deposited directly above a previously unrecognized paleokarst interval. The age of this excursion, and the duration of the associated paleokarst hiatus, are not well constrained, although the events occurred sometime after the Late Famennian Middle expansa Zone. The high positive values recorded in this excursion are consistent with those associated with the youngest Famennian Middle to Late praesulcata Hangenberg Isotopic Excursion in Europe, the isotopic expression of the Hangenberg Event, which included mass extinction, widespread black shale deposition, and a glacio-eustatic fall and rise. If correct, this would considerably revise the age of the Upper Chaffee Group strata of western Colorado. ?? 2011 Elsevier B.V.

  6. Duration of and decoupling between carbon isotope excursions during the end-Triassic mass extinction and Central Atlantic Magmatic Province emplacement

    NASA Astrophysics Data System (ADS)

    Yager, Joyce A.; West, A. Joshua; Corsetti, Frank A.; Berelson, William M.; Rollins, Nick E.; Rosas, Silvia; Bottjer, David J.

    2017-09-01

    Changes in δ13Ccarb and δ13Corg from marine strata occur globally in association with the end-Triassic mass extinction and the emplacement of the Central Atlantic Magmatic Province (CAMP) during the break up of Pangea. As is typical in deep time, the timing and duration of these isotopic excursions has remained elusive, hampering attempts to link carbon cycle perturbations to specific processes. Here, we report δ13Ccarb and δ13Corg from Late Triassic and Early Jurassic strata near Levanto, Peru, where intercalated dated ash beds permit temporal calibration of the carbon isotope record. Both δ13Ccarb and δ13Corg exhibit a broad positive excursion through the latest Triassic into the earliest Jurassic. The first order positive excursion in δ13Corg is interrupted by a negative shift noted in many sections around the world coincident with the extinction horizon. Our data indicate that the negative excursion lasts 85 ± 25 kyrs, longer than inferred by previous studies based on cyclostratigraphy. A 260 ± 80 kyr positive δ13Corg shift follows, during which the first Jurassic ammonites appear. The overall excursion culminates in a return to pre-perturbation carbon isotopic values over the next 1090 ± 70 kyrs. Via chronologic, isotopic, and biostratigraphic correlation to other successions, we find that δ13Ccarb and δ13Corg return to pre-perturbation values as CAMP volcanism ceases and in association with the recovery of pelagic and benthic biota. However, the initiation of the carbon isotope excursion at Levanto predates the well-dated CAMP sills from North America, indicating that CAMP may have started earlier than thought based on these exposures, or that the onset of carbon cycle perturbations was not related to CAMP.

  7. Fission yield and criticality excursion code

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

    Blanchard, A.

    2000-06-30

    The ANSI/ANS 8.3 standard allows a maximum yield not to exceed 2 x 10 fissions to calculate requiring the alarm system to be effective. It is common practice to use this allowance or to develop some other yield based on past criticality accident history or excursion experiments. The literature on the subject of yields discusses maximum yields larger and somewhat smaller than the ANS 8.3 permissive value. The ability to model criticality excursions and vary the various parameters to determine a credible maximum yield for operational specific cases has been available for some time but is not in common usemore » by criticality safety specialists. The topic of yields for various solution, metal, oxide powders, etc. in various geometry's and containers has been published by laboratory specialists or university staff and students for many decades but have not been available to practitioners. The need for best-estimate calculations of fission yields with a well-validated criticality excursion code has long been recognized. But no coordinated effort has been made so far to develop a generalized and well-validated excursion code for different types of systems. In this paper, the current practices to estimate fission yields are summarized along with its shortcomings for the 12-Rad zone (at SRS) and Criticality Alarm System (CAS) calculations. Finally the need for a user-friendly excursion code is reemphasized.« less

  8. A self-powered, one-step chip for rapid, quantitative and multiplexed detection of proteins from pinpricks of whole blood†

    PubMed Central

    Wang, Jun; Ahmad, Habib; Ma, Chao; Shi, Qihui; Vermesh, Ophir; Vermesh, Udi; Heath, James

    2012-01-01

    We describe an automated, self-powered chip based on lateral flow immunoassay for rapid, quantitative, and multiplex protein detection from pinpricks of whole blood. The device incorporates on-chip purification of blood plasma by employing inertial forces to focus blood cells away from the assay surface, where plasma proteins are captured and detected on antibody “barcode” arrays. Power is supplied from the capillary action of a piece of adsorbent paper, and sequentially drives, over a 40 minute period, the four steps required to capture serum proteins and then develop a multiplex immunoassay. An 11 protein panel is assayed from whole blood, with high sensitivity and high reproducibility. This inexpensive, self-contained, and easy to operate chip provides a useful platform for point-of-care diagnoses, particularly in resource-limited settings. PMID:20924527

  9. Probabilistic risk assessment of the Space Shuttle. Phase 3: A study of the potential of losing the vehicle during nominal operation. Volume 5: Auxiliary shuttle risk analyses

    NASA Technical Reports Server (NTRS)

    Fragola, Joseph R.; Maggio, Gaspare; Frank, Michael V.; Gerez, Luis; Mcfadden, Richard H.; Collins, Erin P.; Ballesio, Jorge; Appignani, Peter L.; Karns, James J.

    1995-01-01

    Volume 5 is Appendix C, Auxiliary Shuttle Risk Analyses, and contains the following reports: Probabilistic Risk Assessment of Space Shuttle Phase 1 - Space Shuttle Catastrophic Failure Frequency Final Report; Risk Analysis Applied to the Space Shuttle Main Engine - Demonstration Project for the Main Combustion Chamber Risk Assessment; An Investigation of the Risk Implications of Space Shuttle Solid Rocket Booster Chamber Pressure Excursions; Safety of the Thermal Protection System of the Space Shuttle Orbiter - Quantitative Analysis and Organizational Factors; Space Shuttle Main Propulsion Pressurization System Probabilistic Risk Assessment, Final Report; and Space Shuttle Probabilistic Risk Assessment Proof-of-Concept Study - Auxiliary Power Unit and Hydraulic Power Unit Analysis Report.

  10. Scaphoid tuberosity excursion is minimized during a dart-throwing motion: A biomechanical study.

    PubMed

    Werner, Frederick W; Sutton, Levi G; Basu, Niladri; Short, Walter H; Moritomo, Hisao; St-Amand, Hugo

    2016-01-01

    The purpose of this study was to determine whether the excursion of the scaphoid tuberosity and therefore scaphoid motion is minimized during a dart-throwing motion. Scaphoid tuberosity excursion was studied as an indicator of scaphoid motion in 29 cadaver wrists as they were moved through wrist flexion-extension, radioulnar deviation, and a dart-throwing motion. Study results demonstrate that excursion was significantly less during the dart-throwing motion than during either wrist flexion-extension or radioulnar deviation. If the goal of early wrist motion after carpal ligament or distal radius injury and reconstruction is to minimize loading of the healing structures, a wrist motion in which scaphoid motion is minimal should reduce length changes in associated ligamentous structures. Therefore, during rehabilitation, if a patient uses a dart-throwing motion that minimizes his or her scaphoid tuberosity excursion, there should be minimal changes in ligament loading while still allowing wrist motion. Bench research, biomechanics, and cross-sectional. Not applicable. The study was laboratory based. Copyright © 2016 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

  11. Compensation for large thorax excursions in EIT imaging.

    PubMed

    Schullcke, B; Krueger-Ziolek, S; Gong, B; Mueller-Lisse, U; Moeller, K

    2016-09-01

    Besides the application of EIT in the intensive care unit it has recently also been used in spontaneously breathing patients suffering from asthma bronchiole, cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). In these cases large thorax excursions during deep inspiration, e.g. during lung function testing, lead to artifacts in the reconstructed images. In this paper we introduce a new approach to compensate for image artifacts resulting from excursion induced changes in boundary voltages. It is shown in a simulation study that boundary voltage change due to thorax excursion on a homogeneous model can be used to modify the measured voltages and thus reduce the impact of thorax excursion on the reconstructed images. The applicability of the method on human subjects is demonstrated utilizing a motion-tracking-system. The proposed technique leads to fewer artifacts in the reconstructed images and improves image quality without substantial increase in computational effort, making the approach suitable for real-time imaging of lung ventilation. This might help to establish EIT as a supplemental tool for lung function tests in spontaneously breathing patients to support clinicians in diagnosis and monitoring of disease progression.

  12. Self-Powered Multiparameter Health Sensor.

    PubMed

    Tobola, Andreas; Leutheuser, Heike; Pollak, Markus; Spies, Peter; Hofmann, Christian; Weigand, Christian; Eskofier, Bjoern M; Fischer, Georg

    2018-01-01

    Wearable health sensors are about to change our health system. While several technological improvements have been presented to enhance performance and energy-efficiency, battery runtime is still a critical concern for practical use of wearable biomedical sensor systems. The runtime limitation is directly related to the battery size, which is another concern regarding practicality and customer acceptance. We introduced ULPSEK-Ultra-Low-Power Sensor Evaluation Kit-for evaluation of biomedical sensors and monitoring applications (http://ulpsek.com). ULPSEK includes a multiparameter sensor measuring and processing electrocardiogram, respiration, motion, body temperature, and photoplethysmography. Instead of a battery, ULPSEK is powered using an efficient body heat harvester. The harvester produced 171 W on average, which was sufficient to power the sensor below 25 C ambient temperature. We present design issues regarding the power supply and the power distribution network of the ULPSEK sensor platform. Due to the security aspect of self-powered health sensors, we suggest a hybrid solution consisting of a battery charged by a harvester.

  13. Resolution enhancement in digital holography by self-extrapolation of holograms.

    PubMed

    Latychevskaia, Tatiana; Fink, Hans-Werner

    2013-03-25

    It is generally believed that the resolution in digital holography is limited by the size of the captured holographic record. Here, we present a method to circumvent this limit by self-extrapolating experimental holograms beyond the area that is actually captured. This is done by first padding the surroundings of the hologram and then conducting an iterative reconstruction procedure. The wavefront beyond the experimentally detected area is thus retrieved and the hologram reconstruction shows enhanced resolution. To demonstrate the power of this concept, we apply it to simulated as well as experimental holograms.

  14. 22. WILEY CITY LINE BICENTENNIAL EXCURSION TROLLEY NEAR CONGDON ...

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

    22. WILEY CITY LINE - BICENTENNIAL EXCURSION TROLLEY NEAR CONGDON CASTLE - Yakima Valley Transportation Company Interurban Railroad, Connecting towns of Yakima, Selah & Wiley City, Yakima, Yakima County, WA

  15. On Geomagnetism and Paleomagnetism

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.

    1998-01-01

    A statistical description of Earth's broad scale, core-source magnetic field has been developed and tested. The description features an expected, or mean, spatial magnetic power spectrum that is neither "flat" nor "while" at any depth, but is akin to spectra advanced by Stevenson and McLeod. This multipole spectrum describes the magnetic energy range; it is not steep enough for Gubbins' magnetic dissipation range. Natural variations of core multipole powers about their mean values are to be expected over geologic time and are described via trial probability distribution functions that neither require nor prohibit magnetic isotropy. The description is thus applicable to core-source dipole and low degree non-dipole fields despite axial dipole anisotropy. The description is combined with main field models of modem satellite and surface geomagnetic measurements to make testable predictions of: (1) the radius of Earth's core, (2) mean paleomagnetic field intensity, and (3) the mean rates and durations of both dipole power excursions and durable axial dipole reversals. The predicted core radius is 0.7% above the 3480 km seismologic value. The predicted root mean square paleointensity (35.6 mu T) and mean Virtual Axial Dipole Moment (about 6.2 lx 1022 Am(exp 2)) are within the range of various mean paleointensity estimates. The predicted mean rate of dipole power excursions, as defined by an absolute dipole moment <20% of the 1980 value, is 9.04/Myr and 14% less than obtained by analysis of a 4 Myr paleointensity record. The predicted mean rate of durable axial dipole reversals (2.26/Myr) is 2.3% more than established by the polarity time-scale for the past 84 Myr. The predicted mean duration of axial dipole reversals (5533 yr) is indistinguishable from an observational value. The accuracy of these predictions demonstrates the power and utility of the description, which is thought to merit further development and testing. It is suggested that strong stable stratification of Earth's uppermost outer core leads to a geologically long interval of no dipole reversals and a very nearly axisymmetric field outside the core. Statistical descriptions of other planetary magnetic fields are outlined.

  16. A benchtop biorobotic platform for in vitro observation of muscle-tendon dynamics with parallel mechanical assistance from an elastic exoskeleton.

    PubMed

    Robertson, Benjamin D; Vadakkeveedu, Siddarth; Sawicki, Gregory S

    2017-05-24

    We present a novel biorobotic framework comprised of a biological muscle-tendon unit (MTU) mechanically coupled to a feedback controlled robotic environment simulation that mimics in vivo inertial/gravitational loading and mechanical assistance from a parallel elastic exoskeleton. Using this system, we applied select combinations of biological muscle activation (modulated with rate-coded direct neural stimulation) and parallel elastic assistance (applied via closed-loop mechanical environment simulation) hypothesized to mimic human behavior based on previously published modeling studies. These conditions resulted in constant system-level force-length dynamics (i.e., stiffness), reduced biological loads, increased muscle excursion, and constant muscle average positive power output-all consistent with laboratory experiments on intact humans during exoskeleton assisted hopping. Mechanical assistance led to reduced estimated metabolic cost and MTU apparent efficiency, but increased apparent efficiency for the MTU+Exo system as a whole. Findings from this study suggest that the increased natural resonant frequency of the artificially stiffened MTU+Exo system, along with invariant movement frequencies, may underlie observed limits on the benefits of exoskeleton assistance. Our novel approach demonstrates that it is possible to capture the salient features of human locomotion with exoskeleton assistance in an isolated muscle-tendon preparation, and introduces a powerful new tool for detailed, direct examination of how assistive devices affect muscle-level neuromechanics and energetics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Intermittent Astrophysical Radiation Sources and Terrestrial Life

    NASA Astrophysics Data System (ADS)

    Melott, Adrian

    2013-04-01

    Terrestrial life is exposed to a variety of radiation sources. Astrophysical observations suggest that strong excursions in cosmic ray flux and spectral hardness are expected. Gamma-ray bursts and supernovae are expected to irradiate the atmosphere with keV to GeV photons at irregular intervals. Supernovae will produce large cosmic ray excursions, with time development varying with distance from the event. Large fluxes of keV to MeV protons from the Sun pose a strong threat to electromagnetic technology. The terrestrial record shows cosmogenic isotope excursions which are consistent with major solar proton events, and there are observations of G-stars suggesting that the rate of such events may be much higher than previously assumed. In addition there are unknown and unexplained astronomical transients which may indicate new classes of events. The Sun, supernovae, and gamma-ray bursts are all capable of producing lethal fluences, and some are expected on intervals of 10^8 years or so. The history of life on Earth is filled with mass extinctions at a variety of levels of intensity. Most are not understood. Astrophysical radiation may play a role, particularly from large increases in muon irradiation on the ground, and changes in atmospheric chemistry which deplete ozone, admitting increased solar UVB. UVB is strongly absorbed by DNA and proteins, and breaks the chemical bonds---it is a known carcinogen. High muon fluxes will also be damaging to such molecules, but experiments are needed to pin down the rate. Solar proton events which are not directly dangerous for the biota may nevertheless pose a major threat to modern electromagnetic technology through direct impact on satellites and magnetic induction of large currents in power grids, disabling transformers. We will look at the kind of events that are expected on timescales from human to geological, and their likely consequences.

  18. Burst annealing of high temperature GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Brothers, P. R.; Horne, W. E.

    1991-01-01

    One of the major limitations of solar cells in space power systems is their vulnerability to radiation damage. One solution to this problem is to periodically heat the cells to anneal the radiation damage. Annealing was demonstrated with silicon cells. The obstacle to annealing of GaAs cells was their susceptibility to thermal damage at the temperatures required to completely anneal the radiation damage. GaAs cells with high temperature contacts and encapsulation were developed. The cells tested are designed for concentrator use at 30 suns AMO. The circular active area is 2.5 mm in diameter for an area of 0.05 sq cm. Typical one sun AMO efficiency of these cells is over 18 percent. The cells were demonstrated to be resistant to damage after thermal excursions in excess of 600 C. This high temperature tolerance should allow these cells to survive the annealing of radiation damage. A limited set of experiments were devised to investigate the feasibility of annealing these high temperature cells. The effect of repeated cycles of electron and proton irradiation was tested. The damage mechanisms were analyzed. Limitations in annealing recovery suggested improvements in cell design for more complete recovery. These preliminary experiments also indicate the need for further study to isolate damage mechanisms. The primary objective of the experiments was to demonstrate and quantify the annealing behavior of high temperature GaAs cells. Secondary objectives were to measure the radiation degradation and to determine the effect of repeated irradiation and anneal cycles.

  19. Author Correction: Reliability and feasibility of gait initiation centre-of-pressure excursions using a Wii® Balance Board in older adults at risk of falling.

    PubMed

    Lee, James; Webb, Graham; Shortland, Adam P; Edwards, Rebecca; Wilce, Charlotte; Jones, Gareth D

    2018-05-12

    In the original publication, the article title was incorrectly published as 'Reliability and feasibility of gait initiation centre-of-pressure excursions using a Wii® Balance Board in older adults at risk of failing'. The correct title should read as 'Reliability and feasibility of gait initiation centre-of-pressure excursions using a Wii® Balance Board in older adults at risk of falling'.

  20. Brownian excursions on combs

    NASA Astrophysics Data System (ADS)

    Dean, David S.; Jansons, Kalvis M.

    1993-03-01

    In this paper we use techniques from Ito excursion theory to analyze Brownian motion on generalized combs. Ito excursion theory is a little-known area of probability theory and we therefore present a brief introduction for the uninitiated. A general method for analyzing transport along the backbone of the comb is demonstrated and the specific case of a comb whose teeth are scaling branching trees is examined. We then present a recursive method for evaluating the distribution of the first passage times on hierarchical combs.

  1. Avalanches and scaling collapse in the large-N Kuramoto model

    NASA Astrophysics Data System (ADS)

    Coleman, J. Patrick; Dahmen, Karin A.; Weaver, Richard L.

    2018-04-01

    We study avalanches in the Kuramoto model, defined as excursions of the order parameter due to ephemeral episodes of synchronization. We present scaling collapses of the avalanche sizes, durations, heights, and temporal profiles, extracting scaling exponents, exponent relations, and scaling functions that are shown to be consistent with the scaling behavior of the power spectrum, a quantity independent of our particular definition of an avalanche. A comprehensive scaling picture of the noise in the subcritical finite-N Kuramoto model is developed, linking this undriven system to a larger class of driven avalanching systems.

  2. Empowering self-defense training.

    PubMed

    Thompson, Martha E

    2014-03-01

    The purpose of self-defense training is to expand people's options, yet it is often framed as a solely physical, and limiting, response to violence. I draw on my own experience as a self-defense instructor and that of others in the self-defense movement to argue that an empowerment approach to self-defense training contributes to the anti-violence movement in multiple ways: providing a pathway to increase women's and girls' safety and their potential for becoming powerful and effective social change agents right now, providing an informed and embodied understanding of violence, and offering comprehensive options to recognize, prevent, and interrupt violence.

  3. Sulfur cycling in plays an important role in the development of Ocean Anoxic Events

    NASA Astrophysics Data System (ADS)

    Gomes, M. L.; Raven, M. R.; Fike, D. A.; Gill, B. C.; Johnston, D. T.

    2017-12-01

    Ocean Anoxic Events (OAEs) are major carbon cycle perturbations marked by enhanced organic carbon deposition in the marine realm and carbon isotope excursions in organic and inorganic carbon. Although not as severe as the "big five" mass extinctions, OAEs had dire consequences for marine ecosystems and thus influenced Mesozoic evolutionary patterns. Sulfur cycle reconstructions provide insight into the biogeochemical processes that played a role in the development of OAEs because the sulfur cycle is linked with the carbon and oxygen cycles. We present sulfur and oxygen isotope records from carbonate-associated sulfate from the Toarcian OAE that documents a positive sulfate-oxygen isotope excursion of +6‰, which is similar to the magnitude of the positive sulfur isotope excursion documented at the same site and other globally distributed sites. This high-resolution record allows us to explore temporal variability in the onset of the isotopic excursions: the onset of the positive sulfate-oxygen isotope excursion occurs at the same stratigraphic interval as the onset of the positive carbon isotope excursion and both precede the onset of the positive sulfate-sulfur isotope excursion. Because oxygen is rapidly recycled during oxidative sulfur cycling, changes in oxidative sulfur cycling affect oxygen isotope values of sulfate without impacting sulfur isotope values. Thus, the early onset of the sulfate-oxygen isotope excursion implies a change in oxidative sulfur cycling, which is likely due to a shoaling of the zone of sulfate reduction. We explore the consequences of sulfate reduction zone shoaling for organic carbon preservation. Specifically, the sulfurization of organic matter, which makes organic matter less susceptible to degradation, occurs more rapidly when the top of the zone of sulfate reduction is near or above the sediment water interface. Therefore, we suggest that the shoaling of the sulfate reduction zone locally changed pathways of oxidative sulfur cycling and enhanced organic carbon preservation. Given synchronous changes in similar, globally-distributed depositional environments, this impacted the global biogeochemical cycles of oxygen, carbon, and nutrients in ways that sustained decreased oxygen availability and influenced extinction patterns of marine organisms.

  4. ELM suppression in helium plasmas with 3D magnetic fields

    DOE PAGES

    Evans, T. E.; Loarte, A.; Orlov, D. M.; ...

    2017-06-21

    Experiments in DIII-D, using non-axisymmetric magnetic perturbation fields in high-purity low toroidal rotation, 4He plasmas have resulted in Type-I edge localized mode (ELM) suppression and mitigation. Suppression is obtained in plasmas with zero net input torque near the L–H power threshold using either electron cyclotron resonant heating (ECRH) or balanced co- and counter-I p neutral beam injection (NBI) resulting in conditions equivalent to those expected in ITER's non-active operating phase. In low-power ECRH H-modes, periods with uncontrolled density and impurity radiation excursions are prevented by applying n = 3 non-axisymmetric magnetic perturbation fields. ELM suppression results from a reduction andmore » an outward shift of the electron pressure gradient peak compared to that in the high-power ELMing phase. Here, the change in the electron pressure gradient peak is primarily due to a drop in the pedestal temperature rather than the pedestal density.« less

  5. ELM suppression in helium plasmas with 3D magnetic fields

    NASA Astrophysics Data System (ADS)

    Evans, T. E.; Loarte, A.; Orlov, D. M.; Grierson, B. A.; Knölker, M. M.; Lyons, B. C.; Cui, L.; Gohil, P.; Groebner, R. J.; Moyer, R. A.; Nazikian, R.; Osborne, T. H.; Unterberg, E. A.

    2017-08-01

    Experiments in DIII-D, using non-axisymmetric magnetic perturbation fields in high-purity low toroidal rotation, 4He plasmas have resulted in Type-I edge localized mode (ELM) suppression and mitigation. Suppression is obtained in plasmas with zero net input torque near the L-H power threshold using either electron cyclotron resonant heating (ECRH) or balanced co- and counter-I p neutral beam injection (NBI) resulting in conditions equivalent to those expected in ITER’s non-active operating phase. In low-power ECRH H-modes, periods with uncontrolled density and impurity radiation excursions are prevented by applying n  =  3 non-axisymmetric magnetic perturbation fields. ELM suppression results from a reduction and an outward shift of the electron pressure gradient peak compared to that in the high-power ELMing phase. The change in the electron pressure gradient peak is primarily due to a drop in the pedestal temperature rather than the pedestal density.

  6. An Excursion in Applied Mathematics.

    ERIC Educational Resources Information Center

    von Kaenel, Pierre A.

    1981-01-01

    An excursion in applied mathematics is detailed in a lesson deemed well-suited for the high school student or undergraduate. The problem focuses on an experimental missile guidance system simulated in the laboratory. (MP)

  7. Self-sustainable, high-power-density bio-solar cells for lab-on-a-chip applications.

    PubMed

    Liu, Lin; Choi, Seokheun

    2017-11-07

    A microfluidic lab-on-a-chip system that generates its own power is essential for stand-alone, independent, self-sustainable point-of-care diagnostic devices to work in limited-resource and remote regions. Miniaturized biological solar cells (or micro-BSCs) can be the most suitable power source for those lab-on-a-chip applications because the technique resembles the earth's natural ecosystem - living organisms work in conjunction with non-living components of their environment to create a self-assembling and self-maintaining system. Micro-BSCs can continuously generate electricity from microbial photosynthetic and respiratory activities over day-night cycles, offering a clean and renewable power source with self-sustaining potential. However, the promise of this technology has not been translated into practical applications because of its relatively low power (∼nW cm -2 ) and current short lifetimes (∼a couple of hours). In this work, we enabled high-performance, self-sustaining, long-life micro-BSCs by using fundamental breakthroughs of device architectures and electrode materials. A 3-D biocompatible, conductive, and porous anode demonstrated great microbial biofilm formation and a high rate of bacterial extracellular electron transfer, which led to greater power generation. Furthermore, our micro-BSCs promoted gas exchange to the bacteria through a gas-permeable PDMS membrane in a well-controlled, tightly enclosed micro-chamber, substantially enhancing sustainability. Through photosynthetic reactions of the cyanobacteria Synechocystis sp. PCC 6803 without additional organic fuel, the 90 μL single-chambered bio-solar cell generated a maximum power density of 43.8 μW cm -2 and sustained consistent power production of ∼18.6 μW cm -2 during the day and ∼11.4 μW cm -2 at night for 20 days, which is the highest and longest reported success of any existing micro-scale bio-solar cells.

  8. Power spectrum for the small-scale Universe

    NASA Astrophysics Data System (ADS)

    Widrow, Lawrence M.; Elahi, Pascal J.; Thacker, Robert J.; Richardson, Mark; Scannapieco, Evan

    2009-08-01

    The first objects to arise in a cold dark matter (CDM) universe present a daunting challenge for models of structure formation. In the ultra small-scale limit, CDM structures form nearly simultaneously across a wide range of scales. Hierarchical clustering no longer provides a guiding principle for theoretical analyses and the computation time required to carry out credible simulations becomes prohibitively high. To gain insight into this problem, we perform high-resolution (N = 7203-15843) simulations of an Einstein-de Sitter cosmology where the initial power spectrum is P(k) ~ kn, with -2.5 <= n <= - 1. Self-similar scaling is established for n = -1 and -2 more convincingly than in previous, lower resolution simulations and for the first time, self-similar scaling is established for an n = -2.25 simulation. However, finite box-size effects induce departures from self-similar scaling in our n = -2.5 simulation. We compare our results with the predictions for the power spectrum from (one-loop) perturbation theory and demonstrate that the renormalization group approach suggested by McDonald improves perturbation theory's ability to predict the power spectrum in the quasi-linear regime. In the non-linear regime, our power spectra differ significantly from the widely used fitting formulae of Peacock & Dodds and Smith et al. and a new fitting formula is presented. Implications of our results for the stable clustering hypothesis versus halo model debate are discussed. Our power spectra are inconsistent with predictions of the stable clustering hypothesis in the high-k limit and lend credence to the halo model. Nevertheless, the fitting formula advocated in this paper is purely empirical and not derived from a specific formulation of the halo model.

  9. Vessel Cold-Ironing Using a Barge Mounted PEM Fuel Cell: Project Scoping and Feasibility.

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

    Pratt, Joseph William; Harris, Aaron P.

    2013-01-01

    A barge-mounted hydrogen-fueled proton exchange membrane (PEM) fuel cell system has the potential to reduce emissions and fossil fuel use of maritime vessels in and around ports. This study determines the technical feasibility of this concept and examines specific options on the U.S. West Coast for deployment practicality and potential for commercialization.The conceptual design of the system is found to be straightforward and technically feasible in several configurations corresponding to various power levels and run times.The most technically viable and commercially attractive deployment options were found to be powering container ships at berth at the Port of Tacoma and/or Seattle,more » powering tugs at anchorage near the Port of Oakland, and powering refrigerated containers on-board Hawaiian inter-island transport barges. Other attractive demonstration options were found at the Port of Seattle, the Suisun Bay Reserve Fleet, the California Maritime Academy, and an excursion vessel on the Ohio River.« less

  10. Instant axis of rotation of L4-5 motion segment--a biomechanical study on cadaver lumbar spine.

    PubMed

    Sengupta, Dilip K; Demetropoulos, Constantine K; Herkowitz, Harry N

    2011-06-01

    The instant axis of rotation (IAR) is an important kinematic property to characterise of lumbar spine motion. The goal of this biomechanical study on cadaver lumbar spine was to determine the excursion of the IAR for flexion (FE), lateral bending (LB) and axial rotation (AR) motion at L4-5 segment. Ten cadaver lumbar spine specimens were tested in a 6 degrees-of-freedom spine tester with continuous clyclical loading using pure moment and follower pre-load, to produce physiological motion. The specimens were x-rayed and CT scanned prior to testing to identify marker position. Continuous motion tracking was done by Optotrak motion capture device. A continuous tracking of the IAR excursion was calculated from the continuous motions capturedata using a computer programme. IAR translates forward in flexion and backwards in extension with mean excursion of 26.5 mm (+/- 5.6 SD). During LB motion, IAR translates laterally in the same direction, and the mean excursion was 15.35 mm (+/- 8.75 SD). During axial rotation the IAR translates in the horizontal plane in a semicircular arc, around the centre of the vertebral body, but the IAR translates in the opposite direction of rotation. The IAR excursion was faster and larger during neutral zone motion in FE and LB, but uniform for AR motion. This is the first published data on the continuous excursion of IAR of a lumbar motion segment. The methodology is accurate and precise, but not practicable for in vivo testing.

  11. Complex systems analysis of series of blackouts: cascading failure, critical points, and self-organization.

    PubMed

    Dobson, Ian; Carreras, Benjamin A; Lynch, Vickie E; Newman, David E

    2007-06-01

    We give an overview of a complex systems approach to large blackouts of electric power transmission systems caused by cascading failure. Instead of looking at the details of particular blackouts, we study the statistics and dynamics of series of blackouts with approximate global models. Blackout data from several countries suggest that the frequency of large blackouts is governed by a power law. The power law makes the risk of large blackouts consequential and is consistent with the power system being a complex system designed and operated near a critical point. Power system overall loading or stress relative to operating limits is a key factor affecting the risk of cascading failure. Power system blackout models and abstract models of cascading failure show critical points with power law behavior as load is increased. To explain why the power system is operated near these critical points and inspired by concepts from self-organized criticality, we suggest that power system operating margins evolve slowly to near a critical point and confirm this idea using a power system model. The slow evolution of the power system is driven by a steady increase in electric loading, economic pressures to maximize the use of the grid, and the engineering responses to blackouts that upgrade the system. Mitigation of blackout risk should account for dynamical effects in complex self-organized critical systems. For example, some methods of suppressing small blackouts could ultimately increase the risk of large blackouts.

  12. The Carnian (Late Triassic) carbon isotope excursion: new insights from the terrestrial realm

    NASA Astrophysics Data System (ADS)

    Miller, Charlotte; Kürschner, Wolfram; Peterse, Francien; Baranyi, Viktoria; Reichart, Gert-Jan

    2016-04-01

    The geological record contains evidence for numerous pronounced perturbations in the global carbon cycle, some of which are associated with eruptions from large igneous provinces (LIP), and consequently, ocean acidification and mass extinction. In the Carnian (Late Triassic), evidence from sedimentology and fossil pollen points to a significant change in climate, resulting in biotic turnover: during a period termed the 'Carnian Pluvial Event' (CPE). Additionally, during the Carnian, large volumes of flood basalts were erupted from the Wrangellia LIP (western North America). Evidence from the marine realm suggests a fundamental relationship between the CPE, a global 'wet' period, and the injection of light carbon into the atmosphere from the LIP. Here we provide the first evidence from the terrestrial realm of a significant negative δ13C excursion through the CPE recorded in the sedimentary archive of the Wiscombe Park Borehole, Devon (UK). Both total organic matter and plant leaf waxes reflect a gradual carbon isotope excursion of ~-5‰ during this time interval. Our data provides evidence for the global nature of this isotope excursion, supporting the hypothesis that the excursion was likely the result of an injection of light carbon into the atmosphere from the Wrangellia LIP.

  13. Geometrical effects of conventional and digital prosthodontic planning wax-ups on lateral occlusal contact number, contact area, and steepness.

    PubMed

    Abduo, Jaafar

    2017-01-01

    This study evaluated and compared the effect of conventional and digital wax-ups on three lateral occlusion variables: contact number, contact area, and steepness. Dental casts of 10 patients with Angle Class I relationship were included in the study. All patients required fixed prosthodontic treatment that would affect lateral occlusion. The casts of all patients received conventional and digital wax-ups. For pretreatment, conventional wax-up, and digital wax-up casts, contact number, contact area, and occlusion steepness were measured at four lateral positions, that is, at excursions of 0.5, 1.0, 2.0, and 3.0 mm from maximal intercuspation. Lateral occlusion scheme variables were affected by use of diagnostic wax-ups. For all types of casts, contact number decreased as excursion increased. The two types of wax-ups had similar contact number patterns, and contact number was significantly greater for these casts than for pretreatment casts in the earlier stages of excursion. Similarly, contact area gradually decreased with increasing excursion in the pretreatment and conventional and digital wax-up casts. There was only a minimal decrease in occlusion steepness as excursion increased. However, lateral occlusion was generally steeper for digital wax-up casts.

  14. Fractionating dead reckoning: role of the compass, odometer, logbook, and home base establishment in spatial orientation

    NASA Astrophysics Data System (ADS)

    Wallace, Douglas G.; Martin, Megan M.; Winter, Shawn S.

    2008-06-01

    Rats use multiple sources of information to maintain spatial orientation. Although previous work has focused on rats’ use of environmental cues, a growing number of studies have demonstrated that rats also use self-movement cues to organize navigation. This review examines the extent that kinematic analysis of naturally occurring behavior has provided insight into processes that mediate dead-reckoning-based navigation. This work supports a role for separate systems in processing self-movement cues that converge on the hippocampus. The compass system is involved in deriving directional information from self-movement cues; whereas, the odometer system is involved in deriving distance information from self-movement cues. The hippocampus functions similar to a logbook in that outward path unique information from the compass and odometer is used to derive the direction and distance of a path to the point at which movement was initiated. Finally, home base establishment may function to reset this system after each excursion and anchor environmental cues to self-movement cues. The combination of natural behaviors and kinematic analysis has proven to be a robust paradigm to investigate the neural basis of spatial orientation.

  15. Fractionating dead reckoning: role of the compass, odometer, logbook, and home base establishment in spatial orientation

    PubMed Central

    Martin, Megan M.; Winter, Shawn S.

    2008-01-01

    Rats use multiple sources of information to maintain spatial orientation. Although previous work has focused on rats' use of environmental cues, a growing number of studies have demonstrated that rats also use self-movement cues to organize navigation. This review examines the extent that kinematic analysis of naturally occurring behavior has provided insight into processes that mediate dead-reckoning-based navigation. This work supports a role for separate systems in processing self-movement cues that converge on the hippocampus. The compass system is involved in deriving directional information from self-movement cues; whereas, the odometer system is involved in deriving distance information from self-movement cues. The hippocampus functions similar to a logbook in that outward path unique information from the compass and odometer is used to derive the direction and distance of a path to the point at which movement was initiated. Finally, home base establishment may function to reset this system after each excursion and anchor environmental cues to self-movement cues. The combination of natural behaviors and kinematic analysis has proven to be a robust paradigm to investigate the neural basis of spatial orientation. PMID:18553065

  16. 3D Orthogonal Woven Triboelectric Nanogenerator for Effective Biomechanical Energy Harvesting and as Self-Powered Active Motion Sensors.

    PubMed

    Dong, Kai; Deng, Jianan; Zi, Yunlong; Wang, Yi-Cheng; Xu, Cheng; Zou, Haiyang; Ding, Wenbo; Dai, Yejing; Gu, Bohong; Sun, Baozhong; Wang, Zhong Lin

    2017-10-01

    The development of wearable and large-area energy-harvesting textiles has received intensive attention due to their promising applications in next-generation wearable functional electronics. However, the limited power outputs of conventional textiles have largely hindered their development. Here, in combination with the stainless steel/polyester fiber blended yarn, the polydimethylsiloxane-coated energy-harvesting yarn, and nonconductive binding yarn, a high-power-output textile triboelectric nanogenerator (TENG) with 3D orthogonal woven structure is developed for effective biomechanical energy harvesting and active motion signal tracking. Based on the advanced 3D structural design, the maximum peak power density of 3D textile can reach 263.36 mW m -2 under the tapping frequency of 3 Hz, which is several times more than that of conventional 2D textile TENGs. Besides, its collected power is capable of lighting up a warning indicator, sustainably charging a commercial capacitor, and powering a smart watch. The 3D textile TENG can also be used as a self-powered active motion sensor to constantly monitor the movement signals of human body. Furthermore, a smart dancing blanket is designed to simultaneously convert biomechanical energy and perceive body movement. This work provides a new direction for multifunctional self-powered textiles with potential applications in wearable electronics, home security, and personalized healthcare. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. A note on the self-similar solutions to the spontaneous fragmentation equation

    NASA Astrophysics Data System (ADS)

    Breschi, Giancarlo; Fontelos, Marco A.

    2017-05-01

    We provide a method to compute self-similar solutions for various fragmentation equations and use it to compute their asymptotic behaviours. Our procedure is applied to specific cases: (i) the case of mitosis, where fragmentation results into two identical fragments, (ii) fragmentation limited to the formation of sufficiently large fragments, and (iii) processes with fragmentation kernel presenting a power-like behaviour.

  18. Power of Pen: Expressive Writing as an Intervention Tool on Exposure to Thin-Ideal Images with Dietary Restraint and Self-Compassion as Covariates

    ERIC Educational Resources Information Center

    Relojo, Dennis; Gagani, Angelo Emil

    2016-01-01

    Expressive Writing (EW) has been recognised as an intervention tool for thin-ideal images. However, to date, there are limited studies which investigated its efficacy to involve dietary restraint and self-compassion as moderating variables. The present work assessed the efficacy of EW in improving levels of body satisfaction and positive affect…

  19. International Consensus on Use of Continuous Glucose Monitoring.

    PubMed

    Danne, Thomas; Nimri, Revital; Battelino, Tadej; Bergenstal, Richard M; Close, Kelly L; DeVries, J Hans; Garg, Satish; Heinemann, Lutz; Hirsch, Irl; Amiel, Stephanie A; Beck, Roy; Bosi, Emanuele; Buckingham, Bruce; Cobelli, Claudio; Dassau, Eyal; Doyle, Francis J; Heller, Simon; Hovorka, Roman; Jia, Weiping; Jones, Tim; Kordonouri, Olga; Kovatchev, Boris; Kowalski, Aaron; Laffel, Lori; Maahs, David; Murphy, Helen R; Nørgaard, Kirsten; Parkin, Christopher G; Renard, Eric; Saboo, Banshi; Scharf, Mauro; Tamborlane, William V; Weinzimer, Stuart A; Phillip, Moshe

    2017-12-01

    Measurement of glycated hemoglobin (HbA 1c ) has been the traditional method for assessing glycemic control. However, it does not reflect intra- and interday glycemic excursions that may lead to acute events (such as hypoglycemia) or postprandial hyperglycemia, which have been linked to both microvascular and macrovascular complications. Continuous glucose monitoring (CGM), either from real-time use (rtCGM) or intermittently viewed (iCGM), addresses many of the limitations inherent in HbA 1c testing and self-monitoring of blood glucose. Although both provide the means to move beyond the HbA 1c measurement as the sole marker of glycemic control, standardized metrics for analyzing CGM data are lacking. Moreover, clear criteria for matching people with diabetes to the most appropriate glucose monitoring methodologies, as well as standardized advice about how best to use the new information they provide, have yet to be established. In February 2017, the Advanced Technologies & Treatments for Diabetes (ATTD) Congress convened an international panel of physicians, researchers, and individuals with diabetes who are expert in CGM technologies to address these issues. This article summarizes the ATTD consensus recommendations and represents the current understanding of how CGM results can affect outcomes. © 2017 by the American Diabetes Association.

  20. Standardization versus customization of glucose reporting.

    PubMed

    Rodbard, David

    2013-05-01

    Bergenstal et al. (Diabetes Technol Ther 2013;15:198-211) described an important approach toward standardization of reporting and analysis of continuous glucose monitoring and self-monitoring of blood glucose (SMBG) data. The ambulatory glucose profile (AGP), a composite display of glucose by time of day that superimposes data from multiple days, is perhaps the most informative and useful of the many graphical approaches to display glucose data. However, the AGP has limitations; some variations are desirable and useful. Synchronization with respect to meals, traditionally used in glucose profiles for SMBG data, can improve characterization of postprandial glucose excursions. Several other types of graphical display are available, and recently developed ones can augment the information provided by the AGP. There is a need to standardize the parameters describing glycemic variability and cross-validate the available computer programs that calculate glycemic variability. Clinical decision support software can identify and prioritize clinical problems, make recommendations for modifications of therapy, and explain its justification for those recommendations. The goal of standardization is challenging in view of the diversity of clinical situations and of computing and display platforms and software. Standardization is desirable but must be done in a manner that permits flexibility and fosters innovation.

  1. Self-Powered Real-Time Arterial Pulse Monitoring Using Ultrathin Epidermal Piezoelectric Sensors.

    PubMed

    Park, Dae Yong; Joe, Daniel J; Kim, Dong Hyun; Park, Hyewon; Han, Jae Hyun; Jeong, Chang Kyu; Park, Hyelim; Park, Jung Gyu; Joung, Boyoung; Lee, Keon Jae

    2017-10-01

    Continuous monitoring of an arterial pulse using a pressure sensor attached on the epidermis is an important technology for detecting the early onset of cardiovascular disease and assessing personal health status. Conventional pulse sensors have the capability of detecting human biosignals, but have significant drawbacks of power consumption issues that limit sustainable operation of wearable medical devices. Here, a self-powered piezoelectric pulse sensor is demonstrated to enable in vivo measurement of radial/carotid pulse signals in near-surface arteries. The inorganic piezoelectric sensor on an ultrathin plastic achieves conformal contact with the complex texture of the rugged skin, which allows to respond to the tiny pulse changes arising on the surface of epidermis. Experimental studies provide characteristics of the sensor with a sensitivity (≈0.018 kPa -1 ), response time (≈60 ms), and good mechanical stability. Wireless transmission of detected arterial pressure signals to a smart phone demonstrates the possibility of self-powered and real-time pulse monitoring system. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Requirements for self-magnetically insulated transmission lines

    DOE PAGES

    VanDevender, J. Pace; Pointon, Timothy D.; Seidel, David B.; ...

    2015-03-01

    Self-magnetically insulated transmission lines (MITLs) connect pulsed-power drivers with a load. Although the technology was originally developed in the 1970s and is widely used today in super power generators, failure of the technology is the principal limitation on the power that can be delivered to an experiment. We address issues that are often overlooked, rejected after inadequate simulations, or covered by overly conservative assumptions: (i) electron retrapping in coupling MITLs to loads, (ii) the applicability of collisionless versus collisional electron flow, (iii) power transport efficiency as a function of the geometry at the beginning of the MITL, (iv) gap closuremore » and when gap closure can be neglected, and (v) the role of negative ions in causing anode plasmas and enhancing current losses. We suggest a practical set of conservative design requirements for self-magnetically insulated electron flow based on the results discussed in this paper and on previously published results. The requirements are not necessarily severe constraints in all MITL applications; however, each of the 18 suggested requirements should be examined in the design of a MITL and in the investigation of excessive losses.« less

  3. Paleointensity and 40Ar/39Ar geochronology of basalts at Gamarri, Ethiopia: Correlation with the Réunion subchron and Huckleberry Ridge excursion?

    NASA Astrophysics Data System (ADS)

    Kindley, C.; Macho, A.; Tsegaye, M. A.; Feinberg, J. M.; Singer, B. S.; Jicha, B. R.; Brown, M. C.; Birke, T. K.

    2012-12-01

    Characterization of the geomagnetic field during subchrons, reversals, and excursions is vital to understanding geodynamo processes and interactions across the core-mantle boundary. Moreover, an accurate timescale for geomagnetic field instabilities is critical to global high resolution stratigraphy. The Réunion subchron and Huckleberry Ridge excursion are ideal candidates for study due to globally distributed recordings in both sedimentary and igneous rocks. We present new full-vector paleomagnetic data for 30 basaltic flows from the Gamarri volcanic section in the Afar region of Ethiopia and 11 40Ar/39Ar ages. Paleointensities were calculated using the LTD-DHT Shaw technique and results generally agree with those of Carlut et al. (1999). Two geomagnetic instabilities are recorded, an older excursion and a younger period of normal polarity within the reversed Matuyama chron. Our results show a longer duration of low (<20 μT) paleointensity in the oldest flows and more variable low paleointensity values in the younger flows, and are generally lower than Thellier-style values of Carlut et al. (1999). Relative to 28.201 Ma Fish Canyon sanidine, plateau 40Ar/39Ar ages of the youngest (GB21) and oldest (GA02) flows are 2.029 ± 0.041 (2σ) and 2.410 ± 0.130 Ma, respectively. This eruptive duration is longer than that reported by Kidane et al. (1999), where the unspiked K-Ar method yields ages for GB23 (2 flows overlying GB21) and GA02 of 2.02 ± 0.08 (2σ) and 2.14 ± 0.12 Ma, respectively. 40Ar/39Ar ages of 4 lavas within the normal polarity zone in the upper section are between 2.063 ± 0.044 and 2.118 ± 0.057 Ma, but are indistinguishable at 2σ. These flows may sample the Huckleberry Ridge excursion (2.086 ± 0.016 Ma, Singer et al. 2004), the Réunion subchron (2.153-2.115 Ma, Channell et al. 2003), or both. Given several 40Ar/39Ar ages >2.2 Ma, the older excursion in the Gamarri section is not consistent with the Réunion subchron, and can be linked to any of several excursions occurring between ~2.2 and ~2.5 Ma. These excursions have been observed within records from ODP 982 (Channell & Guyodo, 2004) and IODP U1314 (Ohno et al., 2012), as well as within the GPTS as cryptochron C2r.2r-1 (originally dated as 2.420 to 2.441 Ma by Cande & Kent, 1995). Thus, we no longer interpret the excursion recorded in the lower portion of the Gamarri section to be part of the Réunion subchron and recommend that it be omitted from efforts to construct integrated global field models across the Huckleberry Ridge excursion and Réunion subchron.

  4. Paleomagnetic record for the past 80 ka from the Mahanadi basin, Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Usapkar, A.; Dewangan, P.; Mazumdar, A.; Krishna, K. S.; Ramprasad, T.; Badesab, F. K.; Patil, M.; Gaikwad, V. V.

    2018-01-01

    High resolution paleomagnetic investigations were performed on a 50.08 m long sediment core (MD161/20) from Mahanadi basin, Bay of Bengal. Core yielded reliable paleomagnetic results for top 20 m below seafloor (mbsf) which spans about 80 ka. Based on the analysis of rock magnetic data, the core is subdivided into five distinct Zones: Zone 1 and Zone 2 cover top 20 mbsf and do not show any abrupt change in magnetic mineralogy, concentration and grain size. Zones 3 and 5 show significant reduction in χLF, χARM and SIRM due to dissolution of magnetic minerals. Zone 4 shows moderate values of χLF and SIRM. The low value of χARM suggests that magnetic signal is mostly carried by magnetic grains in PSD/MD state. The paleomagnetic data for the top 20 mbsf show four prominent geomagnetic excursions at ∼9 mbsf, ∼13.5 to 15 mbsf, ∼16.3 mbsf and ∼18 to 18.2 mbsf. The age-depth relationship is established using stratigraphic correlation between well-dated sedimentary core NGHP-01-19B and the core MD161/20. The ages of the observed excursions correspond to ∼18 to 20 ka, ∼42 to 49 ka, ∼54 to 57 ka and ∼69 to 70 ka. The excursions at ∼42 to 49 ka, ∼54 to 57 ka, and ∼67 to 70 ka is similar to the known excursions the Laschamp and the split Norwegian-Greenland Sea events (NGS-I and NGS-II). The excursion at 18-20 ka is not observed globally and may be related to lithological/sedimentological changes occurring during last glacial maxima (LGM). The virtual geomagnetic path (VGP) of Laschamp excursion traces clockwise loop. All excursions identified in present study fall in the periods of relatively low paleointensity.

  5. Improved Quaternary North Atlantic stratigraphy using relative paleointensity (RPI), oxygen isotopes, and magnetic excursions (Invited)

    NASA Astrophysics Data System (ADS)

    Channell, J. E.

    2013-12-01

    Improving the resolution of Quaternary marine stratigraphy is one of the major challenges in paleoceanography. IODP Expedition 303/306, and ODP Legs 162 and 172, have yielded multiple high-resolution records (mean sedimentation rates in the 7-20 cm/kyr range) of relative paleointensity (RPI) that are accompanied by oxygen isotope data and extend through much of the Quaternary. Tandem fit of RPI and oxygen isotope data to calibrated templates (LR04 and PISO), using the Match protocol, yields largely consistent stratigraphies, implying that both RPI and oxygen isotope data are dominated by regional/global signals. Based on the recent geomagnetic field, RPI can be expected to be a global signal (i.e. dominated by the axial dipole field) when recorded at sedimentation rates less than several decimeters/kyr. Magnetic susceptibility, on the other hand, is a local/regional lithologic signal, and therefore less useful for long-distance correlation. Magnetic excursions are directional phenomena and, when adequately recorded, are manifest as paired reversals in which the virtual geomagnetic poles (VGPs) reach high latitudes in the opposite hemisphere, and they occupy minima in RPI records. Reversed VGPs imply that excursions are attributable to the main axial dipole, and therefore provide global stratigraphy. The so-called Iceland Basin excursion is recorded at many IODP/ODP sites and lies at the MIS 6/7 boundary at ~188 ka, with a duration of 2-3 kyr. Other excursions in the Brunhes chron are less commonly recorded because their duration (perhaps <~1 kyr) requires sedimentation rates >20 cm/kyr to be adequately recorded. On the other hand, several excursions within the Matuyama Chron are more commonly recorded in North Atlantic drift sediments due to relatively elevated durations. With some notable exceptions (e.g. Iberian Margin), high quality RPI records from North Atlantic sediments, together with magnetic excursions, can be used in tandem with oxygen isotope data to strengthen Quaternary (North Atlantic) stratigraphy.

  6. Volcanic records of the Laschamp geomagnetic excursion from Mt Ruapehu, New Zealand

    NASA Astrophysics Data System (ADS)

    Ingham, E.; Turner, G. M.; Conway, C. E.; Heslop, D.; Roberts, A. P.; Leonard, G.; Townsend, D.; Calvert, A.

    2017-08-01

    We present palaeodirectional records of the Laschamp geomagnetic excursion from lavas on Mt Ruapehu, New Zealand. Fourteen lava flows on the northwestern and southern flanks of Mt Ruapehu, with 40Ar/39Ar weighted mean plateau ages that range from 46.3 ± 2.0 to 39.9 ± 1.4 ka, were studied. The youngest and older flows carry a normal polarity magnetization; however, six flows, dated between 46.3 ± 2.0 and 42.7 ± 1.8 ka, record excursional directions. Three of these flows record southerly palaeomagnetic declinations and negative inclinations that agree well with a published Laschamp record from the Auckland Volcanic Field (AVF). Together, the AVF and Mt Ruapehu lavas currently represent the only volcanic records of the Laschamp excursion outside the Chaîne des Puys region, France. Thus, they make an important contribution to the global set of Laschamp excursion records. Virtual geomagnetic pole (VGP) groups for the New Zealand and French records early in the excursion are compatible with a dipole-dominated field that rotated to an equatorial orientation while simultaneously decaying in strength. In contrast, younger excursional flows from France and New Zealand yield separate VGP groups, which suggest either that the field had a nondipolar morphology in this later phase, or that the VGP groups were not synchronous. 40Ar/39Ar ages for the Mt Ruapehu record are on average slightly older than published northern hemisphere ages and from the relative palaeointensity minimum in the GLOPIS sedimentary stack. Although few individual ages differ significantly at the 2σ level, the spread suggests an overall excursion duration that is longer than the currently accepted 1500 years. This age spread may result from excess Ar in magmas at the time of the eruption biasing the results to slightly older ages, or from non-synchronous excursional field behaviour at near-antipodal locations, or, possibly, a precursory phase prior to the main excursion.

  7. The relationship between balance performance, lumbar extension strength, trunk extension endurance, and pain in participants with chronic low back pain, and those without.

    PubMed

    Behennah, Jessica; Conway, Rebecca; Fisher, James; Osborne, Neil; Steele, James

    2018-03-01

    Chronic low back pain is associated with lumbar extensor deconditioning. This may contribute to decreased neuromuscular control and balance. However, balance is also influenced by the hip musculature. Thus, the purpose of this study was to examine balance in both asymptomatic participants and those with chronic low back pain, and to examine the relationships among balance, lumbar extension strength, trunk extension endurance, and pain. Forty three asymptomatic participants and 21 participants with non-specific chronic low back pain underwent balance testing using the Star Excursion Balance Test, lumbar extension strength, trunk extension endurance, and pain using a visual analogue scale. Significant correlations were found between lumbar extension strength and Star Excursion Balance Test scores in the chronic low back pain group (r = 0.439-0.615) and in the asymptomatic group (r = 0.309-0.411). Correlations in the chronic low back pain group were consistently found in posterior directions. Lumbar extension strength explained ~19.3% to ~37.8% of the variance in Star Excursion Balance Test scores for the chronic low back pain group and ~9.5% to ~16.9% for the asymptomatic group. These results suggest that the lumbar extensors may be an important factor in determining the motor control dysfunctions, such as limited balance, that arise in chronic low back pain. As such, specific strengthening of this musculature may be an approach to aid in reversing these dysfunctions. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

    Hobbs, Michael L.; Kaneshige, Michael J.; Erikson, William W.

    Here, we have used a modified version of the Sandia Instrumented Thermal Ignition (SITI) experiment to develop a pressure-dependent, five-step ignition model for a plastic bonded explosive (PBX 9501) consisting of 95 wt% octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazoncine (HMX), 2.5 wt% Estane® 5703 (a polyurethane thermoplastic), and 2.5 wt% of a nitroplasticizer (NP): BDNPA/F, a 50/50 wt% eutectic mixture bis(2,2-dinitropropyl)-acetal (BDNPA) and bis(2,2-dinitropropyl)-formal (BDNPF). The five steps include desorption of water, decomposition of the NP to form NO2, reaction of the NO2 with Estane® and HMX, and decomposition of HMX. The model was fit using our experiments and successfully validated with experiments from fivemore » other laboratories with scales ranging from about 2 g to more than 2.5 kg of PBX. Our experimental variables included density, confinement, free gas volume, and temperature. We measured internal temperatures, confinement pressure, and ignition time. In some of our experiments, we used a borescope to visually observe the decomposing PBX. Our observations included the endothermic β–δ phase change of the HMX, a small exothermic temperature excursion in low-density unconfined experiments, and runaway ignition. We hypothesize that the temperature excursion in these low density experiments was associated with the NP decomposing exothermically within the PBX sample. This reactant-limited temperature excursion was not observed with our thermocouples in the high-density experiments. For these experiments, we believe the binder diffused to the edges of our high density samples and decomposed next to the highly conductive wall as confirmed by our borescope images.« less

  9. Mono Lake excursion recorded in sediment of the Santa Clara Valley, California

    USGS Publications Warehouse

    Mankinen, Edward A.; Wentworth, Carl M.

    2004-01-01

    Two intervals recording anomalous paleomagnetic inclinations were encountered in the top 40 meters of research drill hole CCOC in the Santa Clara Valley, California. The younger of these two intervals has an age of 28,090 ± 330 radiocarbon years B.P. (calibrated age ∼32.8 ka). This age is in excellent agreement with the latest estimate for the Mono Lake excursion at the type locality and confirms that the excursion has been recorded by sediment in the San Francisco Bay region. The age of an anomalous inclination change below the Mono Lake excursion was not directly determined, but estimates of sedimentation rates indicate that the geomagnetic behavior it represents most likely occurred during the Mono Lake/Laschamp time interval (∼45–28 ka). If true, it may represent one of several recurring fluctuations of magnetic inclination during an interval of a weak geomagnetic dipole, behavior noted in other studies in the region.

  10. Jaw motion during gum-chewing in children with primary dentition.

    PubMed

    Kubota, Naoko; Hayasaki, Haruaki; Saitoh, Issei; Iwase, Yoko; Maruyama, Tomoaki; Inada, Emi; Hasegawa, Hiroko; Yamada, Chiaki; Takemoto, Yoshihiko; Matsumoto, Yuko; Yamasaki, Youichi

    2010-01-01

    This study was undertaken to characterize jaw motion during mastication in children with primary dentition and to compare jaw motion with that in adults. The means and the variances of the traditional parameters for the chewing cycle, i.e., duration, excursive ranges and 3-D distances of travel at the lower incisor, molars and condyles were analyzed and compared in 23 children and 25 female adults. The duration of opening in children was significantly shorter than that of adults. Significant differences between children and adults were observed in lateral and vertical excursion of the incisor, lateral excursion at the molars, and vertical excursion at the condyles. Many of these measurements had larger between-subject and between-cycle variances in children than adults, suggesting that chewing motion in children has not yet matured. The results of this study indicate that chewing motion in children is different from that of adults.

  11. Finding Limit Cycles in self-excited oscillators with infinite-series damping functions

    NASA Astrophysics Data System (ADS)

    Das, Debapriya; Banerjee, Dhruba; Bhattacharjee, Jayanta K.

    2015-03-01

    In this paper we present a simple method for finding the location of limit cycles of self excited oscillators whose damping functions can be represented by some infinite convergent series. We have used standard results of first-order perturbation theory to arrive at amplitude equations. The approach has been kept pedagogic by first working out the cases of finite polynomials using elementary algebra. Then the method has been extended to various infinite polynomials, where the fixed points of the corresponding amplitude equations cannot be found out. Hopf bifurcations for systems with nonlinear powers in velocities have also been discussed.

  12. Intelligent self-organization methods for wireless ad hoc sensor networks based on limited resources

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2006-05-01

    A wireless ad hoc sensor network (WSN) is a configuration for area surveillance that affords rapid, flexible deployment in arbitrary threat environments. There is no infrastructure support and sensor nodes communicate with each other only when they are in transmission range. To a greater degree than the terminals found in mobile ad hoc networks (MANETs) for communications, sensor nodes are resource-constrained, with limited computational processing, bandwidth, memory, and power, and are typically unattended once in operation. Consequently, the level of information exchange among nodes, to support any complex adaptive algorithms to establish network connectivity and optimize throughput, not only deplete those limited resources and creates high overhead in narrowband communications, but also increase network vulnerability to eavesdropping by malicious nodes. Cooperation among nodes, critical to the mission of sensor networks, can thus be disrupted by the inappropriate choice of the method for self-organization. Recent published contributions to the self-configuration of ad hoc sensor networks, e.g., self-organizing mapping and swarm intelligence techniques, have been based on the adaptive control of the cross-layer interactions found in MANET protocols to achieve one or more performance objectives: connectivity, intrusion resistance, power control, throughput, and delay. However, few studies have examined the performance of these algorithms when implemented with the limited resources of WSNs. In this paper, self-organization algorithms for the initiation, operation and maintenance of a network topology from a collection of wireless sensor nodes are proposed that improve the performance metrics significant to WSNs. The intelligent algorithm approach emphasizes low computational complexity, energy efficiency and robust adaptation to change, allowing distributed implementation with the actual limited resources of the cooperative nodes of the network. Extensions of the algorithms from flat topologies to two-tier hierarchies of sensor nodes are presented. Results from a few simulations of the proposed algorithms are compared to the published results of other approaches to sensor network self-organization in common scenarios. The estimated network lifetime and extent under static resource allocations are computed.

  13. HORIZONTAL BOILING REACTOR SYSTEM

    DOEpatents

    Treshow, M.

    1958-11-18

    Reactors of the boiling water type are described wherein water serves both as the moderator and coolant. The reactor system consists essentially of a horizontal pressure vessel divided into two compartments by a weir, a thermal neutronic reactor core having vertical coolant passages and designed to use water as a moderator-coolant posltioned in one compartment, means for removing live steam from the other compartment and means for conveying feed-water and water from the steam compartment to the reactor compartment. The system further includes auxiliary apparatus to utilize the steam for driving a turbine and returning the condensate to the feed-water inlet of the reactor. The entire system is designed so that the reactor is self-regulating and has self-limiting power and self-limiting pressure features.

  14. Towards full band colorless reception with coherent balanced receivers.

    PubMed

    Zhang, Bo; Malouin, Christian; Schmidt, Theodore J

    2012-04-23

    In addition to linear compensation of fiber channel impairments, coherent receivers also provide colorless selection of any desired data channel within multitude of incident wavelengths, without the need of a channel selecting filter. In this paper, we investigate the design requirements for colorless reception using a coherent balanced receiver, considering both the optical front end (OFE) and the transimpedance amplifier (TIA). We develop analytical models to predict the system performance as a function of receiver design parameters and show good agreement against numerical simulations. At low input signal power, an optimum local oscillator (LO) power is shown to exist where the thermal noise is balanced with the residual LO-RIN beat noise. At high input signal power, we show the dominant noise effect is the residual self-beat noise from the out of band (OOB) channels, which scales not only with the number of OOB channels and the common mode rejection ratio (CMRR) of the OFE, but also depends on the link residual chromatic dispersion (CD) and the orientation of the polarization tributaries relative to the receiver. This residual self-beat noise from OOB channels sets the lower bound for the LO power. We also investigate the limitations imposed by overload in the TIA, showing analytically that the DC current scales only with the number of OOB channels, while the differential AC current scales only with the link residual CD, which induces high peak-to-average power ratio (PAPR). Both DC and AC currents at the input to the TIA set the upper bounds for the LO power. Considering both the OFE noise limit and the TIA overload limit, we show that the receiver operating range is notably narrowed for dispersion unmanaged links, as compared to dispersion managed links. © 2012 Optical Society of America

  15. From the Law of Large Numbers to Large Deviation Theory in Statistical Physics: An Introduction

    NASA Astrophysics Data System (ADS)

    Cecconi, Fabio; Cencini, Massimo; Puglisi, Andrea; Vergni, Davide; Vulpiani, Angelo

    This contribution aims at introducing the topics of this book. We start with a brief historical excursion on the developments from the law of large numbers to the central limit theorem and large deviations theory. The same topics are then presented using the language of probability theory. Finally, some applications of large deviations theory in physics are briefly discussed through examples taken from statistical mechanics, dynamical and disordered systems.

  16. The Objective Force Soldier/Soldier Team. Volume III - Background and Context

    DTIC Science & Technology

    2001-11-01

    last 20 years, was used by RAND to analyze operations in complex terrain (i.e., a treeline ). Since it is limited to simulation in two dimensions, it...the Blue force is inserted through Albania, fights its way into Kosovo, and must evict Serb forces from locations in treelines and cover. Additional...infantry in the treelines were no t countered well by the mounted attack. In addition, a special Blue dismount excursion with current generation equipment

  17. Coupled organic and carbonate δ13C records of the late Triassic and early Jurassic in northern Italy: implications for carbon cycling during the aftermath of the end-Triassic mass extinction

    NASA Astrophysics Data System (ADS)

    Bachan, A.; van de Schootbrugge, B.; Payne, J.

    2011-12-01

    A large protracted positive carbon isotope excursion has been observed in the lowermost Jurassic following the end-Triassic mass extinction. However, the lack of paired records from carbonate rocks (δ13Ccarb) and organic carbon (δ13Corg) and limited biostratigraphic constraints leave open the possibility that variations in δ13Ccarb and δ13Corg are not correlative and do not represent a shift in the δ13C of the global carbon pool. Consequently, the long term carbon cycle behavior following the end-Triassic mass extinction remains incompletely understood. Here we present the first extended, coupled δ13Ccarb and δ13Corg records of the uppermost Triassic and lowermost Jurassic from stratigraphic sections in the Lombardy Basin of northern Italy. The large positive excursion previously observed in the carbonates also occurs in the organics from the same samples, but with a smaller magnitude. Because few post-depositional mechanisms affect the isotopic composition of Ccarb and Corg in similar ways, the correspondence of the two curves presents strong support for a primary origin for the large positive isotopic excursion. The more muted response of the organics is consistent with variation in the fractionation between carbonates and organic carbon, mixing of contemporaneous organic matter with extrabasinal organic carbon of a constant isotopic composition, or some combination of the two. In either case, the occurrence of the positive excursion in multiple locations globally in both carbonates and organic matter is best explained by a change in the isotopic value of the global carbon reservoir. The elevated δ13C values and increased magnitude of the difference between the carbonates and organics is consistent with the predicted biogeochemical consequences of heightened pCO2. The coincidence of the extinction and carbon cycle disturbance with emplacement of the Central Atlantic Magmatic Province suggests that volatiles derived from its emplacement were the likely source of the perturbation.

  18. Performance of Self-developing Radiography Films in LVR-15's Neutron Beams

    NASA Astrophysics Data System (ADS)

    Soltes, Jaroslav; Viererbl, Ladislav; Klupak, Vit; Vins, Miroslav; Michalcova, Bozena

    In the search for a suitable detector for demonstration neutron radiography measurements on the zero-power VR-1 training reactor at the Czech Technical University in Prague, some options were considered. Due to the reactor's low power and spatial limitations, an easy and practical solution had to be found. Self-developing films represent a flexible detection tool in x-ray imaging. Therefore, the goal of this study was to evaluate their potential for neutron detection. For this purpose, bare and converter covered films were studied in the thermal and epithermal neutron beams at the LVR-15 research reactor in Rez, Czech Republic.

  19. Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

    PubMed

    Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

    2016-04-18

    The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.

  20. Aptian Carbon Isotope Stratigraphy in Sierra del Rosario, Northeastern Mexico

    NASA Astrophysics Data System (ADS)

    Barragan-Manzo, R.; Moreno-Bedmar, J.; Nuñez, F.; Company, M.

    2013-05-01

    In most recent years Aptian carbon isotope stratigraphy has been widely studied in Europe where isotopic stages have been developed to correlate global events. Two negative excursions have been recorded in the Lower Aptian, the older is OAE 1a in the middle part, and a younger negative excursion labeled "Aparein level", which occurs in the uppermost part of the Lower Aptian. In Mexico previous works reported a carbon isotope negative excursion in the lowermost part of the La Peña Formation that was assigned to the onset of Oceanic Anoxic Event 1a (=OAE 1a). In this work we study the isotopic record of the δ13Ccarb of 32 bulk rock samples of limestone from the uppermost part of the Cupido Formation and the lower part of the La Peña Formation at the Francisco Zarco Dam Section (=FZD), Durango State, northeastern Mexico. The isotopic data are calibrated using the latest ammonite biostratigraphic biozonation of the Aptian. This age calibration allows us to make a precise correlation between the carbon isotopic record of Mexico and several European sections (e.g. Spain and France). In the studied Francisco Zarco Dam section we recognize a negative carbon isotopic excursion in the Dufrenoyia justinae ammonite Zone that corresponds to the "Aparein level", which we correlate using the ammonite zonation of others European sections (Figure 1). This correlation allows us to see how the negative excursion that characterizes the "Aparein level" is consistent with the C7 segment. Thus, our recent stratigraphic study allows us to conclude that the ammonite record in the lowermost part of the La Peña Formation is regionally isochronous, and correlates with the Dufrenoyia justinae Zone and Lower Aptian isotope interval C7. In agreement to these biostratigraphic data, the supposed record of the OAE 1a in the lowermost part of the La Peña Formation is not correct, and the carbon isotope negative excursion must be assigned to the younger event "Aparein level". Taking this into account, other Lower Aptian negative excursions reported in the literature and assigned to the OAE 1a, perhaps, must be reconsidered to distinguish among the two Lower Aptian negative excursions.; Figure 1: Isotopic curve of the FZD section compared with one section of Spain. The sharp negative peak in the Mexican section is compared with the Spanish section (see the arrow).

  1. Efficient Optical Energy Harvesting in Self-Accelerating Beams

    PubMed Central

    Bongiovanni, Domenico; Hu, Yi; Wetzel, Benjamin; Robles, Raul A.; Mendoza González, Gregorio; Marti-Panameño, Erwin A.; Chen, Zhigang; Morandotti, Roberto

    2015-01-01

    We report the experimental observation of energetically confined self-accelerating optical beams propagating along various convex trajectories. We show that, under an appropriate transverse compression of their spatial spectra, these self-accelerating beams can exhibit a dramatic enhancement of their peak intensity and a significant decrease of their transverse expansion, yet retaining both the expected acceleration profile and the intrinsic self-healing properties. We found our experimental results to be in excellent agreement with the numerical simulations. We expect further applications in such contexts where power budget and optimal spatial confinement can be important limiting factors. PMID:26299360

  2. An experimental study of catalytic and non-catalytic reaction in heat recirculating reactors and applications to power generation

    NASA Astrophysics Data System (ADS)

    Ahn, Jeongmin

    An experimental study of the performance of a Swiss roll heat exchanger and reactor was conducted, with emphasis on the extinction limits and comparison of results with and without Pt catalyst. At Re<40, the catalyst was required to sustain reaction; with the catalyst self-sustaining reaction could be obtained at Re less than 1. Both lean and rich extinction limits were extended with the catalyst, though rich limits were extended much further. At low Re, the lean extinction limit was rich of stoichiometric and rich limit had equivalence ratios 80 in some cases. Non-catalytic reaction generally occurred in a flameless mode near the center of the reactor. With or without catalyst, for sufficiently robust conditions, a visible flame would propagate out of the center, but this flame could only be re-centered with catalyst. Gas chromatography indicated that at low Re, CO and non-C3 H8 hydrocarbons did not form. For higher Re, catalytic limits were slightly broader but had much lower limit temperatures. At sufficiently high Re, catalytic and gas-phase limits merged. Experiments with titanium Swiss rolls have demonstrated reducing wall thermal conductivity and thickness leads to lower heat losses and therefore increases operating temperatures and extends flammability limits. By use of Pt catalysts, reaction of propane-air mixtures at temperatures 54°C was sustained. Such low temperatures suggest that polymers may be employed as a reactor material. A polyimide reactor was built and survived prolonged testing at temperatures up to 500°C. Polymer reactors may prove more practical for microscale devices due to their lower thermal conductivity and ease of manufacturing. Since the ultimate goal of current efforts is to develop combustion driven power generation devices at MEMS like scales, a thermally self-sustaining miniature power generation device was developed utilizing a single-chamber solid-oxide-fuel-cell (SOFC) placed in a Swiss roll. With the single-chamber design, fuel/oxygen crossover due to cracking of seals via thermal cycling is irrelevant and coking on the anode is practically eliminated. SOFC power densities up to 420mW/cm2 were observed at low Re. These results suggest that single-chamber SOFC's integrated with heat-recirculating reactors may be a viable approach for small-scale power generation devices.

  3. Paleomagnetic record determined in cores from deep research wells in the Quaternary Santa Clara basin, California

    USGS Publications Warehouse

    Mankinen, Edward A.; Wentworth, Carl M.

    2016-01-01

    The Mono Lake (ca. 32 ka), Pringle Falls (ca. 210 ka), and Big Lost (ca. 565 ka) geomagnetic excursions all seem to be represented in the Santa Clara Valley wells. Possible correlations to the Laschamp (ca. 40 ka) and Blake (ca. 110 ka) excursions are also noted. Three additional excursions that have apparently not been previously reported from western North America occur within cycle 6 (between 536 and 433 ka), near the base of cycle 5 (after 433 ka), and near the middle of cycle 2 (before ca. 75 ka).

  4. Scaling fixed-field alternating gradient accelerators with a small orbit excursion.

    PubMed

    Machida, Shinji

    2009-10-16

    A novel scaling type of fixed-field alternating gradient (FFAG) accelerator is proposed that solves the major problems of conventional scaling and nonscaling types. This scaling FFAG accelerator can achieve a much smaller orbit excursion by taking a larger field index k. A triplet focusing structure makes it possible to set the operating point in the second stability region of Hill's equation with a reasonable sensitivity to various errors. The orbit excursion is about 5 times smaller than in a conventional scaling FFAG accelerator and the beam size growth due to typical errors is at most 10%.

  5. Four-dimensional analysis by high-speed holographic imaging reveals a chiral memory of sperm flagella.

    PubMed

    Muschol, Michael; Wenders, Caroline; Wennemuth, Gunther

    2018-01-01

    Here high-speed Digital Holographic Microscopy (DHM) records sperm flagellar waveforms and swimming paths in 4 dimensions (X, Z, and t). We find flagellar excursions into the Z-plane nearly as large as the envelope of the flagellar waveform projected onto the XY-plane. These Z-plane excursions travel as waves down the flagellum each beat cycle. DHM also tracks the heads of free-swimming sperm and the dynamics and chirality of rolling of sperm around their long axis. We find that mouse sperm roll CW at the maximum positive Z-plane excursion of the head, then roll CCW at the subsequent maximum negative Z-plane excursion. This alternating chirality of rolling indicates sperm have a chiral memory. Procrustes alignments of path trajectories for sequences of roll-counterroll cycles show that path chirality is always CW for the cells analyzed in this study. Human and bull sperm lack distinguishable left and right surfaces, but DHM still indicates coordination of Z-plane excursions and rolling events. We propose that sperm have a chiral memory that resides in a hypothetical elastic linkage within the flagellar machinery, which stores some of the torque required for a CW or CCW roll to reuse in the following counter-roll. Separate mechanisms control path chirality.

  6. Earth's magnetic field is probably not reversing.

    PubMed

    Brown, Maxwell; Korte, Monika; Holme, Richard; Wardinski, Ingo; Gunnarson, Sydney

    2018-05-15

    The geomagnetic field has been decaying at a rate of ∼5% per century from at least 1840, with indirect observations suggesting a decay since 1600 or even earlier. This has led to the assertion that the geomagnetic field may be undergoing a reversal or an excursion. We have derived a model of the geomagnetic field spanning 30-50 ka, constructed to study the behavior of the two most recent excursions: the Laschamp and Mono Lake, centered at 41 and 34 ka, respectively. Here, we show that neither excursion demonstrates field evolution similar to current changes in the geomagnetic field. At earlier times, centered at 49 and 46 ka, the field is comparable to today's field, with an intensity structure similar to today's South Atlantic Anomaly (SAA); however, neither of these SAA-like fields develop into an excursion or reversal. This suggests that the current weakened field will also recover without an extreme event such as an excursion or reversal. The SAA-like field structure at 46 ka appears to be coeval with published increases in geomagnetically modulated beryllium and chlorine nuclide production, despite the global dipole field not weakening significantly in our model during this time. This agreement suggests a greater complexity in the relationship between cosmogenic nuclide production and the geomagnetic field than is commonly assumed.

  7. Self-triggering superconducting fault current limiter

    DOEpatents

    Yuan, Xing [Albany, NY; Tekletsadik, Kasegn [Rexford, NY

    2008-10-21

    A modular and scaleable Matrix Fault Current Limiter (MFCL) that functions as a "variable impedance" device in an electric power network, using components made of superconducting and non-superconducting electrically conductive materials. The matrix fault current limiter comprises a fault current limiter module that includes a superconductor which is electrically coupled in parallel with a trigger coil, wherein the trigger coil is magnetically coupled to the superconductor. The current surge doing a fault within the electrical power network will cause the superconductor to transition to its resistive state and also generate a uniform magnetic field in the trigger coil and simultaneously limit the voltage developed across the superconductor. This results in fast and uniform quenching of the superconductors, significantly reduces the burnout risk associated with non-uniformity often existing within the volume of superconductor materials. The fault current limiter modules may be electrically coupled together to form various "n" (rows).times."m" (columns) matrix configurations.

  8. Design of an unmanned Martian polar exploration system

    NASA Technical Reports Server (NTRS)

    Baldwin, Curt; Chitwood, Denny; Demann, Brian; Ducheny, Jordan; Hampton, Richard; Kuhns, Jesse; Mercer, Amy; Newman, Shawn; Patrick, Chris; Polakowski, Tony

    1994-01-01

    The design of an unmanned Martian polar exploration system is presented. The system elements include subsystems for transportation of material from earth to Mars, study of the Martian north pole, power generation, and communications. Early next century, three Atlas 2AS launch vehicles will be used to insert three Earth-Mars transfer vehicles, or buses, into a low-energy transfer orbit. Capture at Mars will be accomplished by aerobraking into a circular orbit. Each bus contains four landers and a communications satellite. Six of the twelve total landers will be deployed at 60 deg intervals along 80 deg N, and the remaining six landers at 5 deg intervals along 30 deg E from 65 deg N to 90 deg N by a combination of retrorockets and parachutes. The three communications satellites will be deployed at altitudes of 500 km in circular polar orbits that are 120 deg out of phase. These placements maximize the polar coverage of the science and communications subsystems. Each lander contains scientific equipment, two microrovers, power supplies, communications equipment, and a science computer. The lander scientific equipment includes a microweather station, seismometer, thermal probe, x-ray spectrometer, camera, and sounding rockets. One rover, designed for short-range (less than 2 km) excursions from the lander, includes a mass spectrometer for mineral analysis, an auger/borescope system for depth profiling, a deployable thermal probe, and charge coupled device cameras for terrain visualization/navigation. The second rover, designed for longer-range (2-5 km) excursions from the lander, includes radar sounding/mapping equipment, a seismometer, and laser ranging devices. Power for all subsystems is supplied by a combination of solar cells, Ni-H batteries, and radioisotope thermoelectric generators. Communications are sequenced from rovers, sounding rockets, and remote sensors to the lander, then to the satellites, through the Deep Space Network to and from earth.

  9. Self-contained microfluidic systems: a review.

    PubMed

    Boyd-Moss, Mitchell; Baratchi, Sara; Di Venere, Martina; Khoshmanesh, Khashayar

    2016-08-16

    Microfluidic systems enable rapid diagnosis, screening and monitoring of diseases and health conditions using small amounts of biological samples and reagents. Despite these remarkable features, conventional microfluidic systems rely on bulky expensive external equipment, which hinders their utility as powerful analysis tools outside of research laboratories. 'Self-contained' microfluidic systems, which contain all necessary components to facilitate a complete assay, have been developed to address this limitation. In this review, we provide an in-depth overview of self-contained microfluidic systems. We categorise these systems based on their operating mechanisms into three major groups: passive, hand-powered and active. Several examples are provided to discuss the structure, capabilities and shortcomings of each group. In particular, we discuss the self-contained microfluidic systems enabled by active mechanisms, due to their unique capability for running multi-step and highly controllable diagnostic assays. Integration of self-contained microfluidic systems with the image acquisition and processing capabilities of smartphones, especially those equipped with accessory optical components, enables highly sensitive and quantitative assays, which are discussed. Finally, the future trends and possible solutions to expand the versatility of self-contained, stand-alone microfluidic platforms are outlined.

  10. Scales of care and responsibility: debating the surgically globalised body

    PubMed Central

    Atkinson, Sarah

    2013-01-01

    This paper initiates debate for geographers on the nature of care in relation to the self explored through the practices of aesthetic surgery. Central to debates on the meanings and relations of aesthetic surgery are a set of problematics related to the scales of care and responsibility. These are captured in the distinctions between caring for or caring about and between self-care or care of the self. Aesthetic surgery is a particularly ambivalent ‘extreme care’, which for many is always the expression of consent to an aesthetic hegemony or the exercise of disciplinary power. The paper draws out some of the spatial paradoxes involved in care related to the self in aesthetic surgery and proposes some routes forward. The framework of landscapes of care that enhances a temporal dimension and the concept of reworking the social relations of hegemony may help mediate the inherent tensions of scales of care and responsibility. Specifically, this combination may offer a way to allow for a limited, or bounded, care of the self without negating the networks of power within which the practices of self-care are enacted. PMID:24273456

  11. New self-magnetically insulated connection of multilevel accelerators to a common load

    DOE PAGES

    VanDevender, J. Pace; Langston, William L.; Pasik, Michael F.; ...

    2015-03-04

    A new way to connect pulsed-power modules to a common load is presented. Unlike previous connectors, the clam shell magnetically insulated transmission line (CSMITL) has magnetic nulls only at large radius where the cathode electric field is kept below the threshold for emission, has only a simply connected magnetic topology to avoid plasma motion along magnetic field lines into highly stressed gaps, and has electron injectors that ensure efficient electron flow even in the limiting case of self-limited MITLs. Multilevel magnetically insulated transmission lines with a posthole convolute are the standard solution but associated losses limit the performance of state-of-the-artmore » accelerators. Mitigating these losses is critical for the next generation of pulsed-power accelerators. A CSMITL has been successfully implemented on the Saturn accelerator. A reference design for the Z accelerator is derived and presented. The design conservatively meets the design requirements and shows excellent transport efficiency in three simulations of increasing complexity: circuit simulations, electromagnetic fields only with Emphasis, fields plus electron and ion emission with Quicksilver.« less

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

    Gevorgian, Vahan; Zhang, Yingchen

    The electrical frequency of an interconnected power system must be maintained close its nominal level at all times. Excessive under- and overfrequency excursions can lead to load shedding, instability, machine damage, and even blackouts. There is a rising concern in the electric power industry in recent years about the declining amount of inertia and primary frequency response (PFR) in many interconnections. This decline may continue due to increasing penetrations of inverter-coupled generation and the planned retirements of conventional thermal plants. Inverter-coupled variable wind generation is capable of contributing to PFR and inertia with a response that is different from thatmore » of conventional generation. It is not yet entirely understood how such a response will affect the system at different wind power penetration levels. The modeling work presented in this paper evaluates the impact of wind generation's provision of these active power control strategies on a large, synchronous interconnection. All simulations were conducted on the U.S. Western Interconnection with different levels of instantaneous wind power penetrations (up to 80%). The ability of wind power plants to provide PFR - and a combination of synthetic inertial response and PFR - significantly improved the frequency response performance of the system.« less

  13. Biology Excursions

    ERIC Educational Resources Information Center

    Baldock, R. N.

    1973-01-01

    Provides many useful suggestions and cautions for planning and executing a biology field excursion. Specific procedures are outlined for investigating land communities and coastal areas, and a number of follow-up laboratory activities are described. The appendix provides an extensive bibliography with useful comments on the literature. (JR)

  14. Improving the Science Excursion: An Educational Technologist's View

    ERIC Educational Resources Information Center

    Balson, M.

    1973-01-01

    Analyzes the nature of the learning process and attempts to show how the three components of a reinforcement contingency, the stimulus, the response and the reinforcement can be utilized to increase the efficiency of a typical science learning experience, the excursion. (JR)

  15. Self-adaptive predictor-corrector algorithm for static nonlinear structural analysis

    NASA Technical Reports Server (NTRS)

    Padovan, J.

    1981-01-01

    A multiphase selfadaptive predictor corrector type algorithm was developed. This algorithm enables the solution of highly nonlinear structural responses including kinematic, kinetic and material effects as well as pro/post buckling behavior. The strategy involves three main phases: (1) the use of a warpable hyperelliptic constraint surface which serves to upperbound dependent iterate excursions during successive incremental Newton Ramphson (INR) type iterations; (20 uses an energy constraint to scale the generation of successive iterates so as to maintain the appropriate form of local convergence behavior; (3) the use of quality of convergence checks which enable various self adaptive modifications of the algorithmic structure when necessary. The restructuring is achieved by tightening various conditioning parameters as well as switch to different algorithmic levels to improve the convergence process. The capabilities of the procedure to handle various types of static nonlinear structural behavior are illustrated.

  16. Efficacy and tolerability of exenatide twice daily and exenatide once weekly in Asian versus White patients with type 2 diabetes mellitus: A pooled analysis.

    PubMed

    Sheu, Wayne H-H; Brunell, Steven C; Blase, Erich

    2016-04-01

    The efficacy and safety of exenatide twice daily (BID) and once weekly (QW) were assessed in Asian versus White patients with type 2 diabetes mellitus (T2DM). This post-hoc pooled analysis evaluated patients receiving 10μg exenatide BID for 12-30 weeks or 2mg exenatide QW for 24-30 weeks in exenatide clinical development program trials. Race was self-identified. A total of 4625 patients were included (exenatide BID: Asian, n=787; White, n=2223; exenatide QW: Asian, n=511; White, n=1104). At study end, glycated hemoglobin (HbA1c), fasting glucose (FG), body weight, post-prandial glucose (PPG), and PPG excursions were significantly reduced (all P<0.0001 vs baseline). For exenatide BID, HbA1c reduction was greater in Asians (P<0.0001 vs Whites), whereas HbA1c reduction did not differ by race for exenatide QW. FG reduction did not differ by race for either exenatide formulation. Weight reduction was significantly greater in Whites (P<0.0001 vs Asians), regardless of exenatide formulation. PPG reduction was greater in Asians (P<0.0001 vs Whites) for exenatide BID but did not differ by race for exenatide QW. For exenatide BID, reductions in PPG excursions for all meals were significantly greater in Asians (P<0.0001 vs Whites), whereas only post-breakfast and post-lunch excursions were significantly greater in Asians for exenatide QW (P=0.0009 and P=0.0189 vs Whites, respectively). Common adverse events included nausea, headache, and diarrhea. Exenatide BID and QW improved glycemic control, including PPG, in Asian and White patients with T2DM. With exenatide BID, Asian patients exhibited significantly greater reductions in HbA1c and PPG than White patients. Both exenatide formulations were well tolerated in both groups. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  17. Advertising largely self regulated but controls more explicit in other countries

    DOT National Transportation Integrated Search

    2000-09-30

    Article compares controls for advertizing for automobile performance in United States versus other contries. Controls seem much more explicit in other countries. The rights of free speech and other limits of regulatory power are recognized as prohibi...

  18. Influence of dietary protein on postprandial blood glucose levels in individuals with Type 1 diabetes mellitus using intensive insulin therapy.

    PubMed

    Paterson, M A; Smart, C E M; Lopez, P E; McElduff, P; Attia, J; Morbey, C; King, B R

    2016-05-01

    To determine the effects of protein alone (independent of fat and carbohydrate) on postprandial glycaemia in individuals with Type 1 diabetes mellitus using intensive insulin therapy. Participants with Type 1 diabetes mellitus aged 7-40 years consumed six 150 ml whey isolate protein drinks [0 g (control), 12.5, 25, 50, 75 and 100] and two 150 ml glucose drinks (10 and 20 g) without insulin, in randomized order over 8 days, 4 h after the evening meal. Continuous glucose monitoring was used to assess postprandial glycaemia. Data were collected from 27 participants. Protein loads of 12.5 and 50 g did not result in significant postprandial glycaemic excursions compared with control (water) throughout the 300 min study period (P > 0.05). Protein loads of 75 and 100 g resulted in lower glycaemic excursions than control in the 60-120 min postprandial interval, but higher excursions in the 180-300 min interval. In comparison with 20 g glucose, the large protein loads resulted in significantly delayed and sustained glucose excursions, commencing at 180 min and continuing to 5 h. Seventy-five grams or more of protein alone significantly increases postprandial glycaemia from 3 to 5 h in people with Type 1 diabetes mellitus using intensive insulin therapy. The glycaemic profiles resulting from high protein loads differ significantly from the excursion from glucose in terms of time to peak glucose and duration of the glycaemic excursion. This research supports recommendations for insulin dosing for large amounts of protein. © 2015 The Authors. Diabetic Medicine published by John Wiley & Sons Ltd on behalf of Diabetes UK.

  19. Sex-specific gait adaptations prior to and up to six months after ACL reconstruction

    PubMed Central

    Stasi, Stephanie L. Di; Hartigan, Erin H.; Snyder-Mackler, Lynn

    2015-01-01

    STUDY DESIGN Controlled longitudinal laboratory study. OBJECTIVES Compare sagittal plane gait mechanics of men and women before and up to 6 months after anterior cruciate ligament reconstruction (ACLR). BACKGROUND Aberrant gait patterns are ubiquitous after anterior cruciate ligament (ACL) rupture and persist after ACLR despite skilled physical therapy. Sex influences post-operative function and second ACL injury risk, but its influence on gait adaptations after injury have not been investigated. METHODS Sagittal plane knee and hip joint excursions during midstance and internal knee and hip extension moments at peak knee flexion were collected on 12 women and 27 men using 3-dimensional gait analysis before (Screen) and after pre-operative physical therapy (Pre-sx), and 6 months after ACLR (6mo). Repeated measures analysis of variance models were used to determine whether limb asymmetries changed differently over time in men and women. RESULTS Significant time x limb x sex interactions were identified for hip and knee excursions and internal knee extension moments (P≤.007). Both sexes demonstrated smaller knee excursions on the involved compared to the uninvolved knee at each time point (P≤.007), but only women demonstrated a decrease in the involved knee excursion from pre-sx to 6mo (P=.03). Women also demonstrated smaller hip excursions (P<.001) and internal knee extension moments (P=.005) on the involved limb compared to the uninvolved limb at 6mo. Men demonstrated smaller hip excursions and knee moments on the involved limb compared to the uninvolved limb (main effects, P<.001). CONCLUSION The persistence of limb asymmetries in men and women 6 months after ACLR indicates that current rehabilitation efforts are inadequate for some individuals following ACLR. PMID:25627155

  20. The Record of Geomagnetic Excursions from a ~150 m Sediment Core: Clear Lake, Northern California

    NASA Astrophysics Data System (ADS)

    Levin, E.; Byrne, R.; Looy, C. V.; Wahl, D.; Noren, A. J.; Verosub, K. L.

    2015-12-01

    We are studying the paleomagnetic properties of a new ~150 meter drill core from Clear Lake, CA. Step-wise demagnetization of the natural remanent magnetism (NRM) yields stable directions after 20 mT, implying that the sediments are reliable recorders of geomagnetic field behavior. Several intervals of low relative paleointensity (RPI) from the core appear to be correlated with known geomagnetic excursions. At about 46 m depth, and ~33 ka according to an age model based on radiocarbon dates obtained from pollen and the Olema ash bed, a low RPI zone seems to agree with the age and duration of the Mono Lake Excursion, previously identified between 32 and 35 ka. Slightly lower in the core, at about 50 m depth and ~40 ka, noticeably low RPI values seem to be coeval with the Laschamp excursion, which has been dated at ~41 ka. A volcanic ash near the bottom of the core (141 mblf) is near the same depth as an ash identified in 1988 by Andrei Sarna-Wojcicki and others as the Loleta ash bed in a previous Clear Lake core. If the basal ash in the new core is indeed the, Loleta ash bed, then the core may date back to about 270-300 ka. Depending on the age of the lowest ash, a sequence of low RPI intervals could correlate with the Blake (120 ka), Iceland Basin (188 ka), Jamaica/Pringle Falls (211 ka), and CR0 (260 ka) excursions. Correlation of the low RPI intervals to these geomagnetic excursions will help in the development of a higher resolution chronostratigraphy for the core, resolve a long-standing controversy about a possible hiatus in the Clear Lake record, and provide information about climatically-driven changes in sedimentation.

  1. Prediction of the 21-cm signal from reionization: comparison between 3D and 1D radiative transfer schemes

    NASA Astrophysics Data System (ADS)

    Ghara, Raghunath; Mellema, Garrelt; Giri, Sambit K.; Choudhury, T. Roy; Datta, Kanan K.; Majumdar, Suman

    2018-05-01

    Three-dimensional radiative transfer simulations of the epoch of reionization can produce realistic results, but are computationally expensive. On the other hand, simulations relying on one-dimensional radiative transfer solutions are faster but limited in accuracy due to their more approximate nature. Here, we compare the performance of the reionization simulation codes GRIZZLY and C2-RAY which use 1D and 3D radiative transfer schemes, respectively. The comparison is performed using the same cosmological density fields, halo catalogues, and source properties. We find that the ionization maps, as well as the 21-cm signal maps from these two simulations are very similar even for complex scenarios which include thermal feedback on low-mass haloes. The comparison between the schemes in terms of the statistical quantities such as the power spectrum of the brightness temperature fluctuation agrees with each other within 10 per cent error throughout the entire reionization history. GRIZZLY seems to perform slightly better than the seminumerical approaches considered in Majumdar et al. which are based on the excursion set principle. We argue that GRIZZLY can be efficiently used for exploring parameter space, establishing observations strategies, and estimating parameters from 21-cm observations.

  2. Self-organizing intelligent network of smart electrical heating devices as an alternative to traditional ways of heating

    NASA Astrophysics Data System (ADS)

    Zaslavsky, Aleksander M.; Tkachov, Viktor V.; Protsenko, Stanislav M.; Bublikov, Andrii V.; Suleimenov, Batyrbek; Orshubekov, Nurbek; Gromaszek, Konrad

    2017-08-01

    The paper considers the problem of automated decentralized distribution of the electric energy among unlimited-power electric heaters providing the given temperature distribution within the zones of monitored object heating in the context of maximum use of electric power which limiting level is time-dependent randomly. Principles of collective selforganization automata for solving the problem are analyzed. It has been shown that after all the automata make decision, equilibrium of Nash type is attained when unused power within the electric network is not more than a power of any non-energized electric heater.

  3. Speckle tracking as a method to measure hemidiaphragm excursion.

    PubMed

    Goutman, Stephen A; Hamilton, James D; Swihart, Blake; Foerster, Bradley; Feldman, Eva L; Rubin, Jonathan M

    2017-01-01

    Diaphragm excursion measured via ultrasound may be an important imaging outcome measure of respiratory function. We developed a new method for measuring diaphragm movement and compared it to the more traditional M-mode method. Ultrasound images of the right and left hemidiaphragms were collected to compare speckle tracking and M-mode measurements of diaphragm excursion. Speckle tracking was performed using EchoInsight (Epsilon Imaging, Ann Arbor, Michigan). Six healthy subjects without a history of pulmonary diseases were included in this proof-of-concept study. Speckle tracking of the diaphragm is technically possible. Unlike M-mode, speckle tracking carries the advantage of reliable visualization and measurement of the left hemidiaphragm. Speckle tracking accounted for diaphragm movement simultaneously in the cephalocaudad and mediolateral directions, unlike M-mode, which is 1-dimensional. Diaphragm speckle tracking may represent a novel, more robust method for measuring diaphragm excursion, especially for the left hemidiaphragm. Muscle Nerve 55: 125-127, 2017. © 2016 Wiley Periodicals, Inc.

  4. Geomagnetic paleointensities from excursion sequences in lavas on Oahu, Hawaii

    USGS Publications Warehouse

    Coe, Robert S.; Gromme, Sherman; Mankinen, Edward A.

    1984-01-01

    Paleomagnetic data demonstrating three late Tertiary excursions in the direction of the geomagnetic field recorded in sequences of basaltic lavas on the island of Oahu, Hawaii were published by R. R. Doell and G. B. Dalrymple in 1973. We have determined geomagnetic paleointensities by the Thelliers' method for 14 lavas from the three sites. During these experiments, considerable difficulty was encountered because of the presence of titanomaghemite in many lavas and the contamination of natural remanent magnetization by lightning in many others. Moreover, we often observed the production of spurious high‐temperature chemical remanent magnetization during the Thellier experiments. An analysis of this particularly troublesome problem is presented. Two of the sites showed low paleointensities associated with angular departures of the paleomagnetic field direction from that of a geocentric axial dipole, which suggests that these excursions represent aborted reversals or fragments of reversals. At the third site, however, the paleointensity did not become low as the field diverged. This excursion may reflect the variation of a large nondipole source near Hawaii.

  5. Novel Self-Heated Gas Sensors Using on-Chip Networked Nanowires with Ultralow Power Consumption.

    PubMed

    Tan, Ha Minh; Manh Hung, Chu; Ngoc, Trinh Minh; Nguyen, Hugo; Duc Hoa, Nguyen; Van Duy, Nguyen; Hieu, Nguyen Van

    2017-02-22

    The length of single crystalline nanowires (NWs) offers a perfect pathway for electron transfer, while the small diameter of the NWs hampers thermal losses to tje environment, substrate, and metal electrodes. Therefore, Joule self-heating effect is nearly ideal for operating NW gas sensors at ultralow power consumption, without additional heaters. The realization of the self-heated NW sensors using the "pick and place" approach is complex, hardly reproducible, low yield, and not applicable for mass production. Here, we present the sensing capability of the self-heated networked SnO 2 NWs effectively prepared by on-chip growth. Our developed self-heated sensors exhibit a good response of 25.6 to 2.5 ppm NO 2 gas, while the response to 500 ppm H 2 , 100 ppm NH 3 , 100 ppm H 2 S, and 500 ppm C 2 H 5 OH is very low, indicating the good selectivity of the sensors to NO 2 gas. Furthermore, the detection limit is very low, down to 82 parts-per-trillion. As-obtained sensing performance under self-heating mode is nearly identical to that under external heating mode. While the power consumption under self-heating mode is extremely low, around hundreds of microwatts, as scaled-down the size of the electrode is below 10 μm. The selectivity of the sensors can be controlled simply by tuning the loading power that enables simple detection of NO 2 in mixed gases. Remarkable performance together with a significantly facile fabrication process of the present sensors enhances the potential application of NW sensors in next generation technologies such as electronic noses, the Internet of Things, and smartphone sensing.

  6. Self-Reported Knee Instability Before and After Total Knee Replacement Surgery.

    PubMed

    Fleeton, Genevieve; Harmer, Alison R; Nairn, Lillias; Crosbie, Jack; March, Lyn; Crawford, Ross; van der Esch, Martin; Fransen, Marlene

    2016-04-01

    To determine the prevalence and burden of pain and activity limitations associated with retaining presurgery self-reported knee instability 6 months after total knee replacement (TKR) surgery and to identify early potentially modifiable risk factors for retaining knee instability in the operated knee after TKR surgery. A secondary analysis was performed using measures obtained from 390 participants undergoing primary unilateral TKR and participating in a randomized clinical trial. Self-reported knee instability was measured using 2 items from the Activities of Daily Living Scale of the Knee Outcome Survey. Outcome measures were knee pain (range 0-20) and physical function (range 0-68) on the Western Ontario and McMaster Universities Arthritis Index (WOMAC), stair-climb power, 50-foot walk time, knee range of motion, and isometric knee flexion and extension strength. In this study, 72% of participants reported knee instability just prior to surgery, with 32% retaining instability in the operated knee 6 months after surgery. Participants retaining operated knee instability had significantly more knee pain and activity limitations 6 months after surgery, with mean ± SD WOMAC scores of 4.8 ± 3.7 and 17.5 ± 11.1, respectively, compared to participants without knee instability, with 2.9 ± 3.1 and 9.8 ± 9.2. The multivariable predictor model for retained knee instability included a high comorbidity score (>6), low stair-climb power (<150 watts), more pain in the operated knee (>7 of 20), and younger age (<60 years). Self-reported knee instability is highly prevalent before and after TKR surgery and is associated with a considerable burden of pain and activity limitation in the operated knee. Increasing lower extremity muscle power may reduce the risk of retaining knee instability after TKR surgery. © 2016, American College of Rheumatology.

  7. Illness and injury to students on a school excursion to Peru.

    PubMed

    Shaw, Marc T M; Harding, Elizabeth; Leggat, Peter A

    2014-01-01

    School-organized travels abroad provide an opportunity for students to undertake supervised travel that reinforces scholastic study of various geographical locations under the direction and protection of experienced tour leaders and health professional support. Little is known concerning the nature of illnesses and injuries occurring on overseas school excursions. This study was designed to investigate the prevalence of injury and illness suffered by older teenagers on a school excursion to South America. In 2010, the school's tour physician (EH) diagnosed and recorded all illnesses and injuries among 29 school girls and 6 accompanying adults on a school excursion to Peru. Information recorded included age, sex, the nature of the presenting illness, number of days into the tour, the assessment of the condition, and the treatment employed during the excursion's field phase of 21 days. A total of 32 (91%) travelers sought medical advice at least once for a total of 371 consultations, resulting in 153 separate diagnoses. The mean age of the students was 16 years with six adults accompanying the students being significantly older. Primary illnesses diagnosed were related to the following systems and conditions: gastrointestinal (58, 37%), respiratory (25, 16%), altitude sickness (19, 12%), genitourinary (8, 5%), dermatological (10, 7%), trauma (7, 5%), neurological (7, 5%), anxiety or psychological adjustment (7, 5%), adverse drug reactions (4, 3%), and musculoskeletal (5, 3%). The most commonly used medications were antidiarrheal and antiemetic medication. There were six accidents during the journey resulting in minor soft-tissue injuries. There were no deaths or other major accidents requiring emergency evacuation or hospitalization. On this school excursion, the health problems encountered were consistent with those reported for other specialized tours, including expeditions and premium tours, although altitude illness needs to be carefully planned for in tours to higher elevation destinations as in South America. As well as being part of the service provided to the school students, the inclusion of a physician with appropriate medical supplies for this tour increased the independence of the travel group. A proposed medical kit for such an excursion is presented. © 2014 International Society of Travel Medicine.

  8. Occupant kinematics in low-speed frontal sled tests: Human volunteers, Hybrid III ATD, and PMHS.

    PubMed

    Beeman, Stephanie M; Kemper, Andrew R; Madigan, Michael L; Franck, Christopher T; Loftus, Stephen C

    2012-07-01

    A total of 34 dynamic matched frontal sled tests were performed, 17 low (2.5g, Δv=4.8kph) and 17 medium (5.0g, Δv=9.7kph), with five male human volunteers of approximately 50th percentile height and weight, a Hybrid III 50th percentile male ATD, and three male PMHS. Each volunteer was exposed to two impulses at each severity, one relaxed and one braced prior to the impulse. A total of four tests were performed at each severity with the ATD and one trial was performed at each severity with each PMHS. A Vicon motion analysis system, 12 MX-T20 2 megapixel cameras, was used to quantify subject 3D kinematics (±1mm) (1kHz). Excursions of select anatomical regions were normalized to their respective initial positions and compared by test condition and between subject types. The forward excursions of the select anatomical regions generally increased with increasing severity. The forward excursions of relaxed human volunteers were significantly larger than those of the ATD for nearly every region at both severities. The forward excursions of the upper body regions of the braced volunteers were generally significantly smaller than those of the ATD at both severities. Forward excursions of the relaxed human volunteers and PMHSs were fairly similar except the head CG response at both severities and the right knee and C7 at the medium severity. The forward excursions of the upper body of the PMHS were generally significantly larger than those of the braced volunteers at both severities. Forward excursions of the PMHSs exceeded those of the ATD for all regions at both severities with significant differences within the upper body regions. Overall human volunteers, ATD, and PMHSs do not have identical biomechanical responses in low-speed frontal sled tests but all contribute valuable data that can be used to refine and validate computational models and ATDs used to assess injury risk in automotive collisions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Stimulated Brillouin scattering reduction induced by self-focusing for a single laser speckle interacting with an expanding plasma

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

    Masson-Laborde, P. E.; Depierreux, S.; Loiseau, P.

    2014-03-15

    The origin of the low level of stimulated Brillouin scattering (SBS) observed in laser-plasma experiments carried out with a single laser speckle is investigated by means of three-dimensional simulations and modeling in the limit when the laser beam power P is well above the critical power for ponderomotive self-focusing We find that the order of magnitude of the time averaged reflectivities, together with the temporal and spatial SBS localization observed in our simulations, are correctly reproduced by our modeling. It is observed that, after a short transient stage, SBS reaches a significant level only (i) as long as the incidentmore » laser pulse is increasing in amplitude and (ii) in a single self-focused speckle located in the low-density front part of the plasma. In order to describe self-focusing in an inhomogeneous expanding plasma, we have derived a new Lagrangian density describing this process. Using then a variational approach, our model reproduces the position and the peak intensity of the self-focusing hot spot in the front part of the plasma density profile as well as the local density depletion in this hot spot. The knowledge of these parameters then makes it possible to estimate the spatial amplification of SBS as a function of the laser beam power and consequently to explain the experimentally observed SBS reflectivity, considerably reduced with respect to standard theory in the regime of large laser beam power.« less

  10. Quasi-CW diode-pumped self-starting adaptive laser with self-Q-switched output.

    PubMed

    Smith, G; Damzen, M J

    2007-05-14

    An investigation is made into a quasi-CW (QCW) diode-pumped holographic adaptive laser utilising an ultra high gain (approximately 10(4)) Nd:YVO(4) bounce amplifier. The laser produces pulses at 1064 nm with energy approximately 0.6 mJ, duration <3 ns and peak power approximately 200 kW, with high stability, via self-Q-switching effects due to the transient dynamics of the writing and replay of the gain hologram for each pump pulse. The system produces a near-diffraction-limited output with M(2)<1.3 and operates with a single longitudinal mode. In a further adaptive laser configuration, the output was amplified to obtain pulses of approximately 5.6 mJ energy, approximately 7 ns duration and approximately 1 MW peak power. The output spatial quality is also M(2)<1.3 with SLM operation. Up to 2.9 mJ pulse energy of frequency doubled green (532 nm) radiation is obtained, using an LBO crystal, representing approximately 61% conversion efficiency. This work shows that QCW diode-pumped self-adaptive holographic lasers can provide a useful source of high peak power, short duration pulses with excellent spatial quality and narrow linewidth spectrum.

  11. Enhancing the Dependability of Complex Missions Through Automated Analysis

    DTIC Science & Technology

    2013-09-01

    triangular or self - referential relationships. The Semantic Web Rule Language (SWRL)—a W3C-approved OWL extension—addresses some of these limitations by...SWRL extends OWL with Horn-like rules that can model complex relational structures and self - referential relationships; Prolog extends OWL+SWRL with the...8]. Additionally, multi-agent model checking has been used to verify OWL-S process models [9]. OWL is a powerful knowledge representation formalism

  12. On the possibility of observing bound soliton pairs in a wave-breaking-free mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Martel, G.; Chédot, C.; Réglier, V.; Hideur, A.; Ortaç, B.; Grelu, Ph.

    2007-02-01

    On the basis of numerical simulations, we explain the formation of the stable bound soliton pairs that were experimentally reported in a high-power mode-locked ytterbium fiber laser [Opt. Express 14, 6075 (2006)], in a regime where wave-breaking-free operation is expected. A fully vectorial model allows one to rigorously reproduce the nonmonotonic nature for the nonlinear polarization effect that generally limits the power scalability of a single-pulse self-similar regime. Simulations show that a self-similar regime is not fully obtained, although positive linear chirps and parabolic spectra are always reported. As a consequence, nonvanishing pulse tails allow distant stable binding of highly-chirped pulses.

  13. Modeling the measured effect of a nitroplasticizer (BDNPA/F) on cookoff of a plastic bonded explosive (PBX 9501)

    DOE PAGES

    Hobbs, Michael L.; Kaneshige, Michael J.; Erikson, William W.

    2016-09-12

    Here, we have used a modified version of the Sandia Instrumented Thermal Ignition (SITI) experiment to develop a pressure-dependent, five-step ignition model for a plastic bonded explosive (PBX 9501) consisting of 95 wt% octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazoncine (HMX), 2.5 wt% Estane® 5703 (a polyurethane thermoplastic), and 2.5 wt% of a nitroplasticizer (NP): BDNPA/F, a 50/50 wt% eutectic mixture bis(2,2-dinitropropyl)-acetal (BDNPA) and bis(2,2-dinitropropyl)-formal (BDNPF). The five steps include desorption of water, decomposition of the NP to form NO2, reaction of the NO2 with Estane® and HMX, and decomposition of HMX. The model was fit using our experiments and successfully validated with experiments from fivemore » other laboratories with scales ranging from about 2 g to more than 2.5 kg of PBX. Our experimental variables included density, confinement, free gas volume, and temperature. We measured internal temperatures, confinement pressure, and ignition time. In some of our experiments, we used a borescope to visually observe the decomposing PBX. Our observations included the endothermic β–δ phase change of the HMX, a small exothermic temperature excursion in low-density unconfined experiments, and runaway ignition. We hypothesize that the temperature excursion in these low density experiments was associated with the NP decomposing exothermically within the PBX sample. This reactant-limited temperature excursion was not observed with our thermocouples in the high-density experiments. For these experiments, we believe the binder diffused to the edges of our high density samples and decomposed next to the highly conductive wall as confirmed by our borescope images.« less

  14. Self-similar relativistic blast waves with energy injection

    NASA Astrophysics Data System (ADS)

    van Eerten, Hendrik

    2014-08-01

    A sufficiently powerful astrophysical source with power-law luminosity in time will give rise to a self-similar relativistic blast wave with a reverse shock travelling into the ejecta and a forward shock moving into the surrounding medium. Once energy injection ceases and the last energy is delivered to the shock front, the blast wave will transit into another self-similar stage depending only on the total amount of energy injected. I describe the effect of limited duration energy injection into environments with density depending on radius as a power law, emphasizing optical/X-ray Gamma-ray Burst afterglows as applications. The blast wave during injection is treated analytically, the transition following last energy injection with one-dimensional simulations. Flux equations for synchrotron emission from the forward and reverse shock regions are provided. The reverse shock emission can easily dominate, especially with different magnetizations for both regions. Reverse shock emission is shown to support both the reported X-ray and optical correlations between afterglow plateau duration and end time flux, independently of the luminosity power-law slope. The model is demonstrated by application to bursts 120521A and 090515, and can accommodate their steep post-plateau light-curve slopes.

  15. Immediate Effects of a Single Session of Motor Skill Training on the Lumbar Movement Pattern During a Functional Activity in People With Low Back Pain: A Repeated-Measures Study.

    PubMed

    Marich, Andrej V; Lanier, Vanessa M; Salsich, Gretchen B; Lang, Catherine E; Van Dillen, Linda R

    2018-04-06

    People with low back pain (LBP) may display an altered lumbar movement pattern of early lumbar motion compared to people with healthy backs. Modifying this movement pattern during a clinical test decreases pain. It is unknown whether similar effects would be seen during a functional activity. The objective of this study is was to examine the lumbar movement patterns before and after motor skill training, effects on pain, and characteristics that influenced the ability to modify movement patterns. The design consisted of a repeated-measures study examining early-phase lumbar excursion in people with LBP during a functional activity test. Twenty-six people with chronic LBP received motor skill training, and 16 people with healthy backs were recruited as a reference standard. Twenty minutes of motor skill training to decrease early-phase lumbar excursion during the performance of a functional activity were used as a treatment intervention. Early-phase lumbar excursion was measured before and after training. Participants verbally reported increased pain, decreased pain, or no change in pain during performance of the functional activity test movement in relation to their baseline pain. The characteristics of people with LBP that influenced the ability to decrease early-phase lumbar excursion were examined. People with LBP displayed greater early-phase lumbar excursion before training than people with healthy backs (LBP: mean = 11.2°, 95% CI = 9.3°-13.1°; healthy backs: mean = 7.1°, 95% CI = 5.8°-8.4°). Following training, the LBP group showed a decrease in the amount of early-phase lumbar excursion (mean change = 4.1°, 95% CI = 2.4°-5.8°); 91% of people with LBP reported that their pain decreased from baseline following training. The longer the duration of LBP (β = - 0.22) and the more early-phase lumbar excursion before training (β = - 0.82), the greater the change in early-phase lumbar excursion following training. The long-term implications of modifying the movement pattern and whether the decrease in pain attained was clinically significant are unknown. People with LBP were able to modify their lumbar movement pattern and decrease their pain with the movement pattern within a single session of motor skill training.

  16. Engaging students in research learning experiences through hydrology field excursions and short films

    NASA Astrophysics Data System (ADS)

    Ewen, Tracy; Seibert, Jan

    2015-04-01

    One of the best ways to engage students and instill enthusiasm for hydrology is to expose them to hands-on learning. A focus on hydrology field research can be used to develop context-rich and active learning, and help solidify idealized learning where students are introduced to individual processes through textbook examples, often neglecting process interactions and an appreciation for the complexity of the system. We introduced a field course where hydrological measurement techniques are used to study processes such as snow hydrology and runoff generation, while also introducing students to field research and design of their own field project. Additionally, we produced short films of each of these research-based field excursions, with in-house film expertise. These films present a short overview of field methods applied in alpine regions and will be used for our larger introductory hydrology courses, exposing students to field research at an early stage, and for outreach activities, including for potential high school students curious about hydrology. In the field course, students design a low-budget experiment with the aim of going through the different steps of a 'real' scientific project, from formulating the research question to presenting their results. During the field excursions, students make discharge measurements in several alpine streams with a salt tracer to better understand the spatial characteristics of an alpine catchment, where source waters originate and how they contribute to runoff generation. Soil moisture measurements taken by students in this field excursion were used to analyze spatial soil moisture patterns in the alpine catchment and subsequently used in a publication. Another field excursion repeats a published experiment, where preferential soil flow paths are studied using a tracer and compared to previously collected data. For each field excursion, observational data collected by the students is uploaded to an online database we developed, where students can also retrieve data from past excursions to further analyze and compare their data. At each of the field sites, weather stations were installed and a webviewer allows access to realtime data from data loggers, allowing students to explore how processes relate to climatic conditions. Together, these field excursions give students the necessary tools they will need to carry out field research of their own in future projects, whether in academia or industry, while the short films give potential or first-year students an impression of what hydrology is all about and hopefully inspire them to become future hydrologists.

  17. A gaussian model for simulated geomagnetic field reversals

    NASA Astrophysics Data System (ADS)

    Wicht, Johannes; Meduri, Domenico G.

    2016-10-01

    Field reversals are the most spectacular events in the geomagnetic history but remain little understood. Here we explore the dipole behaviour in particularly long numerical dynamo simulations to reveal statistically significant conditions required for reversals and excursions to happen. We find that changes in the axial dipole moment behaviour are crucial while the equatorial dipole moment plays a negligible role. For small Rayleigh numbers, the axial dipole always remains strong and stable and obeys a clearly Gaussian probability distribution. Only when the Rayleigh number is increased sufficiently the axial dipole can reverse and its distribution becomes decisively non-Gaussian. Increased likelihoods around zero indicate a pronounced lingering in a new low dipole moment state. Reversals and excursions can only happen when axial dipole fluctuations are large enough to drive the system from the high dipole moment state assumed during stable polarity epochs into the low dipole moment state. Since it is just a matter of chance which polarity is amplified during dipole recovery, reversals and grand excursions, i.e. excursions during which the dipole assumes reverse polarity, are equally likely. While the overall reversal behaviour seems Earth-like, a closer comparison to palaeomagnetic findings suggests that the simulated events last too long and that grand excursions are too rare. For a particularly large Ekman number we find a second but less Earth-like type of reversals where the total field decays and recovers after a certain time.

  18. Carbon isotopic shift and its cause at the Wuchiapingian-Changhsingian boundary in the Upper Permian at the Zhaojiaba section, South China: Evidences from multiple geochemical proxies

    NASA Astrophysics Data System (ADS)

    Wei, Hengye; Yu, Hao; Wang, Jianguo; Qiu, Zhen; Xiang, Lei; Shi, Guo

    2015-06-01

    The Late Permian environmental change, connecting the Guadalupian-Lopingian (G-L) (Middle-Upper Permian) boundary mass extinction and the Permain-Triassic (P-Tr) boundary mass extinction, has attracted more and more attentions. A significant negative shift for carbon isotope had been found at the Wuchiapingian-Changhsingian (W-C) boundary in the Upper Permian recently. However, the cause(s) of this negative excursion is still unknown. To resolve this problem, we analyzed the bulk organic carbon isotope, total organic carbon (TOC) content, pyritic sulfur (Spy) content, major element concentrations, and molecular organic biomarkers in the Wujiaping and Dalong formations in the Upper Permian from the Zhaojiaba section in western Hubei province, South China. Our results show that (1) there was a significant negative excursion in organic carbon isotopes at the W-C boundary and again a negative excursion at the top of Changhsingian stage; (2) the significant negative excursion at the W-C boundary was probably a global signal and mainly caused by the low primary productivity; and (3) the negative carbon isotope excursion at the top of Changhsingian was probably caused by the Siberian Traps eruptions. A decline in oceanic primary productivity at the W-C boundary probably represents a disturbance of the marine food web, leading to a vulnerable ecosystem prior to the P-Tr boundary mass extinction.

  19. Transient boiling in two-phase helium natural circulation loops

    NASA Astrophysics Data System (ADS)

    Furci, H.; Baudouy, B.; Four, A.; Meuris, C.

    2014-01-01

    Two-phase helium natural circulation loops are used for cooling large superconducting magnets, as CMS for LHC. During normal operation or in the case of incidents, transients are exerted on the cooling system. Here a cooling system of this type is studied experimentally. Sudden power changes are operated on a vertical-heated-section natural convection loop, simulating a fast increase of heat deposition on magnet cooling pipes. Mass flow rate, heated section wall temperature and pressure drop variations are measured as a function of time, to assess the time behavior concerning the boiling regime according to the values of power injected on the heated section. The boiling curves and critical heat flux (CHF) values have been obtained in steady state. Temperature evolution has been observed in order to explore the operating ranges where heat transfer is deteriorated. Premature film boiling has been observed during transients on the heated section in some power ranges, even at appreciably lower values than the CHF. A way of attenuating these undesired temperature excursions has been identified through the application of high enough initial heating power.

  20. An experimental apparatus to simulate body-powered prosthetic usage: Development and preliminary evaluation.

    PubMed

    Gao, Fan; Rodriguez, Johanan; Kapp, Susan

    2016-06-01

    Harness fitting in the body-powered prosthesis remains more art than science due to a lack of consistent and quantitative evaluation. The aim of this study was to develop a mechanical, human-body-shaped apparatus to simulate body-powered upper limb prosthetic usage and evaluate its capability of quantitative examination of harness configuration. The apparatus was built upon a torso of a wooden mannequin and integrated major mechanical joints to simulate terminal device operation. Sensors were used to register cable tension, cable excursion, and grip force simultaneously. The apparatus allowed the scapula to move up to 127 mm laterally and the load cell can measure the cable tension up to 445 N. Our preliminary evaluation highlighted the needs and importance of investigating harness configurations in a systematic and controllable manner. The apparatus allows objective, systematic, and quantitative evaluation of effects of realistic harness configurations and will provide insightful and working knowledge on harness fitting in upper limb amputees using body-powered prosthesis. © The International Society for Prosthetics and Orthotics 2015.

  1. Reinforcing the North Atlantic backbone: revision and extension of the composite splice at ODP Site 982

    NASA Astrophysics Data System (ADS)

    Drury, Anna Joy; Westerhold, Thomas; Hodell, David; Röhl, Ursula

    2018-03-01

    Ocean Drilling Program (ODP) Site 982 represents a key location for understanding the evolution of climate in the North Atlantic over the past 12 Ma. However, concerns exist about the validity and robustness of the underlying stratigraphy and astrochronology, which currently limits the adequacy of this site for high-resolution climate studies. To resolve this uncertainty, we verify and extend the early Pliocene to late Miocene shipboard composite splice at Site 982 using high-resolution XRF core scanning data and establish a robust high-resolution benthic foraminiferal stable isotope stratigraphy and astrochronology between 8.0 and 4.5 Ma. Splice revisions and verifications resulted in ˜ 11 m of gaps in the original Site 982 isotope stratigraphy, which were filled with 263 new isotope analyses. This new stratigraphy reveals previously unseen benthic δ18O excursions, particularly prior to 6.65 Ma. The benthic δ18O record displays distinct, asymmetric cycles between 7.7 and 6.65 Ma, confirming that high-latitude climate is a prevalent forcing during this interval. An intensification of the 41 kyr beat in both the benthic δ13C and δ18O is also observed ˜ 6.4 Ma, marking a strengthening in the cryosphere-carbon cycle coupling. A large ˜ 0.7 ‰ double excursion is revealed ˜ 6.4-6.3 Ma, which also marks the onset of an interval of average higher δ18O and large precession and obliquity-dominated δ18O excursions between 6.4 and 5.4 Ma, coincident with the culmination of the late Miocene cooling. The two largest benthic δ18O excursions ˜ 6.4-6.3 Ma and TG20/22 coincide with the coolest alkenone-derived sea surface temperature (SST) estimates from Site 982, suggesting a strong connection between the late Miocene global cooling, and deep-sea cooling and dynamic ice sheet expansion. The splice revisions and revised astrochronology resolve key stratigraphic issues that have hampered correlation between Site 982, the equatorial Atlantic and the Mediterranean. Comparisons of the revised Site 982 stratigraphy to high-resolution astronomically tuned benthic δ18O stratigraphies from ODP Site 926 (equatorial Atlantic) and Ain el Beida (north-western Morocco) show that prior inconsistencies in short-term excursions are now resolved. The identification of key new cycles at Site 982 further highlights the requirement for the current scheme for late Miocene marine isotope stages to be redefined. Our new integrated deep-sea benthic stable isotope stratigraphy and astrochronology from Site 982 will facilitate future high-resolution late Miocene to early Pliocene climate research.

  2. Application of Raman spectroscopy technology to studying Sudan I

    NASA Astrophysics Data System (ADS)

    Li, Gang; Zhang, Guoping; Chen, Chen

    2006-06-01

    Being an industrial dye, the Sudan I may have a toxic effect after oral intake on the body, and has recently been shown to cause cancer in rats, mice and rabbits. Because China and some other countries have detected the Sudan I in samples of the hot chilli powder and the chilli products, it is necessary to study the characteristics of this dye. As one kind of molecule scattering spectroscopy, Raman spectroscopy is characterized by the frequency excursion caused by interactions of molecules and photons. The frequency excursion reflects the margin between certain two vibrational or rotational energy states, and shows the information of the molecule. Because Raman spectroscopy can provides quick, easy, reproducible, and non-destructive analysis, both qualitative and quantitative, with no sample preparation required, Raman spectroscopy has been a particularly promising technique for analyzing the characteristics and structures of molecules, especially organic ones. Now, it has a broad application in biological, chemical, environmental and industrial applications. This paper firstly introduces Sudan I dye and the Raman spectroscopy technology, and then describes its application to the Sudan I. Secondly, the fingerprint spectra of the Sudan I are respectively assigned and analyzed in detail. Finally, the conclusion that the Raman spectroscopy technology is a powerful tool to determine the Sudan I is drawn.

  3. Ultra-High Temperature Steam Corrosion of Complex Silicates for Nuclear Applications: A Computational Study

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

    Rashkeev, Sergey N.; Glazoff, Michael V.; Tokuhiro, Akira

    2014-01-01

    Stability of materials under extreme conditions is an important issue for safety of nuclear reactors. Presently, silicon carbide (SiC) is being studied as a cladding material candidate for fuel rods in boiling-water and pressurized water-cooled reactors (BWRs and PWRs) that would substitute or modify traditional zircaloy materials. The rate of corrosion of the SiC ceramics in hot vapor environment (up to 2200 degrees C) simulating emergency conditions of light water reactor (LWR) depends on many environmental factors such as pressure, temperature, viscosity, and surface quality. Using the paralinear oxidation theory developed for ceramics in the combustion reactor environment, we estimatedmore » the corrosion rate of SiC ceramics under the conditions representing a significant power excursion in a LWR. It was established that a significant time – at least 100 h – is required for a typical SiC braiding to significantly degrade even in the most aggressive vapor environment (with temperatures up to 2200 °C) which is possible in a LWR at emergency condition. This provides evidence in favor of using the SiC coatings/braidings for additional protection of nuclear reactor rods against off-normal material degradation during power excursions or LOCA incidents. Additionally, we discuss possibilities of using other silica based ceramics in order to find materials with even higher corrosion resistance than SiC. In particular, we found that zircon (ZrSiO4) is also a very promising material for nuclear applications. Thermodynamic and first-principles atomic-scale calculations provide evidence of zircon thermodynamic stability in aggressive environments at least up to 1535 degrees C.« less

  4. Concept Developed for an Implanted Stimulated Muscle-Powered Piezoelectric Generator

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth; Kilgore, Kevin; Ercegovic, David; Gustafson, Kenneth

    2005-01-01

    Implanted electronic devices are typically powered by batteries or transcutaneous power transmission. Batteries must be replaced or recharged, and transcutaneous power sources burden the patient or subject with external equipment prone to failure. A completely self-sustaining implanted power source would alleviate these limitations. Skeletal muscle provides an available autologous power source containing native chemical energy that produces power in excess of the requirements for muscle activation by motor nerve stimulation. A concept has been developed to convert stimulated skeletal muscle power into electrical energy (see the preceding illustration). We propose to connect a piezoelectric generator between a muscle tendon and bone. Electrically stimulated muscle contractions would exert force on the piezoelectric generator, charging a storage circuit that would be used to power the stimulator and other devices.

  5. Differential effects of power training versus functional task practice on compensation and restoration of arm function after stroke.

    PubMed

    Corti, Manuela; McGuirk, Theresa E; Wu, Samuel S; Patten, Carolynn

    2012-09-01

    Improved upper-extremity (UE) movement with stroke rehabilitation may involve restoration of more normal or development of compensatory movement patterns. The authors investigated the differential effects of functional task practice (FTP) and dynamic resistance training (POWER) on clinical function and reaching kinematics in an effort to distinguish between mechanisms of gains. A total of 14 hemiparetic individuals were randomly assigned to 10 weeks of either FTP or POWER and then crossed over to 10 weeks of the alternate treatment. Treatment order A was FTP followed by POWER, whereas treatment order B was POWER followed by FTP. Evaluation before and after each treatment block included a battery of clinical evaluations and kinematics of paretic UE functional reach to grasp. Both FTP and POWER improved movement accuracy, as revealed by a shift toward normal, including fewer submovements and reduced reach-path ratio. However, active range of motion revealed differential treatment effects. Shoulder flexion and elbow extension decreased with FTP and were associated with increased trunk displacement. In contrast, shoulder flexion and elbow extension excursion increased with POWER and were associated with significantly reduced trunk displacement. Treatment order B (POWER followed by FTP) revealed greater overall improvements. FTP increases compensatory movement patterns to improve UE function. POWER leads to more normal movement patterns. POWER prior to FTP may enhance the benefits of repetitive task practice.

  6. A computer controlled power tool for the servicing of the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Richards, Paul W.; Konkel, Carl; Smith, Chris; Brown, Lee; Wagner, Ken

    1996-01-01

    The Hubble Space Telescope (HST) Pistol Grip Tool (PGT) is a self-contained, microprocessor controlled, battery-powered, 3/8-inch-drive hand-held tool. The PGT is also a non-powered ratchet wrench. This tool will be used by astronauts during Extravehicular Activity (EVA) to apply torque to the HST and HST Servicing Support Equipment mechanical interfaces and fasteners. Numerous torque, speed, and turn or angle limits are programmed into the PGT for use during various missions. Batteries are replaceable during ground operations, Intravehicular Activities, and EVA's.

  7. Environmental control on the paleo- and environmental magnetic record on the Yermak Plateau, Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Wiers, Steffen; Snowball, Ian; O'Regan, Matt; Almqvist, Bjarne

    2017-04-01

    The Yermak Plateau, situated north of Svalbard, has been recognized as one of several places in the Arctic Ocean where paleomagnetism yields controversial results. Despite low sedimentation rates, excursional paleomagnetic directions have been reconstructed from many cores in the region. Commonly reported geomagnetic excursions, i.e. Laschamp, Norwegian-Greenland-Sea and Blake, show considerably longer durations and younger ages compared to established short-lived geomagnetic polarity microchrons. An environmental control on the paleomagnetic record, connected to self-reversal during maghemitization of titanomagnetite has been proposed as one explanation for the wide occurrence of anomalous paleomagnetic data in the Arctic Ocean, but it remains unclear what mechanisms are responsible. Without independent stratigraphic control and independent dating it is difficult to distinguish between true and false records of the paleomagnetic field. Here we present a paleo- and environmental magnetic record from an 8.6 m long oriented Kasten core (PS92/39-02) collected at 1464 m water depth on the Yermak Plateau (81.94°N 13.82°E). The density and magnetic susceptibility fit well into the regional stratigraphy and allow for correlation of different parameters with independently dated records. During AF demagnetization zones with a weak-medium gyro-remanence and/or spurious ARM acquisition were observed at fields above 70 mT, but in some instances above 50 mT, coinciding with shallow to positive inclination zones. Based on a gyro-cleaned record the initial paleomagnetic age model fits well into the regional constraints. The top of the core was assigned to be recent, the first observed excursion was assigned to Laschamp (ca. 41ka), the second to Norwegian-Greenland Sea (ca. 70-80 ka) and the top of the third to Blake (ca. 110 ka). With no excursions observed below Blake, the bottom of the sediment sequence was assumed to be younger than 180 ka (the age of the Iceland Basin/Pringle Falls excursion). We applied this basic age model to kARM/k (magnetic grain size proxy) and the resulting temporal trend is very similar to the global oxygen isotope record of ice volume. The waxing and waning of the Svalbard-Barent Sea Ice Sheet is the main control on terrigenous input to the Yermak Plateau and thus link d18O and magnetic grain-size. With records spanning more than 2-3 glacial cycles orbital tuning could further support our findings. Finally, we propose the use of magnetic grain-size (as of kARM/k) as an independent tuning mechanism for dating sediments from the Yermak Plateau.

  8. 46 CFR 176.204 - Permit to carry excursion party.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., survival craft, life jacket, fire safety, and manning standards applicable to a vessel in the service for... may carry, the crew required, any additional lifesaving or safety equipment required, the route for... waive the applicable minimum safety standards when issuing an excursion permit. In particular, a vessel...

  9. 46 CFR 176.204 - Permit to carry excursion party.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., survival craft, life jacket, fire safety, and manning standards applicable to a vessel in the service for... may carry, the crew required, any additional lifesaving or safety equipment required, the route for... waive the applicable minimum safety standards when issuing an excursion permit. In particular, a vessel...

  10. 46 CFR 176.204 - Permit to carry excursion party.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., survival craft, life jacket, fire safety, and manning standards applicable to a vessel in the service for... may carry, the crew required, any additional lifesaving or safety equipment required, the route for... waive the applicable minimum safety standards when issuing an excursion permit. In particular, a vessel...

  11. 40 CFR 63.1334 - Parameter monitoring levels and excursions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... period for the storage vessel. (ii) If the monitoring plan does not specify monitoring a parameter and... semiannually or quarterly. The first semiannual period is the 6-month period starting the date the Notification... period—two excused excursions. (6) For the sixth and all subsequent semiannual periods—one excused...

  12. Design of high-capacity fiber-optic transport systems

    NASA Astrophysics Data System (ADS)

    Liao, Zhi Ming

    2001-08-01

    We study the design of fiber-optic transport systems and the behavior of fiber amplifiers/lasers with the aim of achieving higher capacities with larger amplifier spacing. Solitons are natural candidates for transmitting short pulses for high-capacity fiber-optic networks because of its innate ability to use two of fiber's main defects, fiber dispersion and fiber nonlinearity to balance each other. In order for solitons to retain its dynamic nature, amplifiers must be placed periodically to restore powers to compensate for fiber loss. Variational analysis is used to study the long-term stability of a periodical- amplifier system. A new regime of operation is identified which allows the use of a much longer amplifier spacing. If optical fibers are the blood vessels of an optical communication system, then the optical amplifier based on erbium-doped fiber is the heart. Optical communication systems can avoid the use of costly electrical regenerators to maintain system performance by being able to optically amplify the weakened signals. The length of amplifier spacing is largely determined by the gain excursion experienced by the solitons. We propose, model, and demonstrate a distributed erbium-doped fiber amplifier which can drastically reduce the amount of gain excursion experienced by the solitons, therefore allowing a much longer amplifier spacing and superior stability. Dispersion management techniques have become extremely valuable tools in the design of fiber-optic communication systems. We have studied in depth the advantage of different arnplification schemes (lumped and distributed) for various dispersion compensation techniques. We measure the system performance through the Q factor to evaluate the added advantage of effective noise figure and smaller gain excursion. An erbium-doped fiber laser has been constructed and characterized in an effort to develop a test bed to study transmission systems. The presence of mode-partition noise in an erbium-doped fiber laser was experimentally demonstrated. A numerical model has been developed using the Langevin rate equations and its predictions are in qualitative agreement with experimental data.

  13. 75 FR 6748 - Self-Regulatory Organizations; The NASDAQ Stock Market LLC; Notice of Filing of Proposed Rule...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-10

    ... on a first-come/first-serve basis. Should available cabinet inventory shrink to 40 cabinets or less... be limited to a maximum power level of 5kW. Should available cabinet inventory shrink to zero, the...

  14. Chance-Constrained System of Systems Based Operation of Power Systems

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

    Kargarian, Amin; Fu, Yong; Wu, Hongyu

    In this paper, a chance-constrained system of systems (SoS) based decision-making approach is presented for stochastic scheduling of power systems encompassing active distribution grids. Based on the concept of SoS, the independent system operator (ISO) and distribution companies (DISCOs) are modeled as self-governing systems. These systems collaborate with each other to run the entire power system in a secure and economic manner. Each self-governing system accounts for its local reserve requirements and line flow constraints with respect to the uncertainties of load and renewable energy resources. A set of chance constraints are formulated to model the interactions between the ISOmore » and DISCOs. The proposed model is solved by using analytical target cascading (ATC) method, a distributed optimization algorithm in which only a limited amount of information is exchanged between collaborative ISO and DISCOs. In this paper, a 6-bus and a modified IEEE 118-bus power systems are studied to show the effectiveness of the proposed algorithm.« less

  15. Brain talk: power and negotiation in children’s discourse about self, brain and behaviour

    PubMed Central

    Singh, Ilina

    2013-01-01

    This article examines children’s discourse about self, brain and behaviour, focusing on the dynamics of power, knowledge and responsibility articulated by children. The empirical data discussed in this article are drawn from the study of Voices on Identity, Childhood, Ethics and Stimulants, which included interviews with 151 US and UK children, a subset of whom had a diagnosis of attention deficit/hyperactivity disorder. Despite their contact with psychiatric explanations and psychotropic drugs for their behaviour, children’s discursive engagements with the brain show significant evidence of agency and negotiated responsibility. These engagements suggest the limitations of current concepts that describe a collapse of the self into the brain in an age of neurocentrism. Empirical investigation is needed in order to develop agent-centred conceptual and theoretical frameworks that describe and evaluate the harms and benefits of treating children with psychotropic drugs and other brain-based technologies. PMID:23094965

  16. Self-powered textile for wearable electronics by hybridizing fiber-shaped nanogenerators, solar cells, and supercapacitors.

    PubMed

    Wen, Zhen; Yeh, Min-Hsin; Guo, Hengyu; Wang, Jie; Zi, Yunlong; Xu, Weidong; Deng, Jianan; Zhu, Lei; Wang, Xin; Hu, Chenguo; Zhu, Liping; Sun, Xuhui; Wang, Zhong Lin

    2016-10-01

    Wearable electronics fabricated on lightweight and flexible substrate are believed to have great potential for portable devices, but their applications are limited by the life span of their batteries. We propose a hybridized self-charging power textile system with the aim of simultaneously collecting outdoor sunshine and random body motion energies and then storing them in an energy storage unit. Both of the harvested energies can be easily converted into electricity by using fiber-shaped dye-sensitized solar cells (for solar energy) and fiber-shaped triboelectric nanogenerators (for random body motion energy) and then further stored as chemical energy in fiber-shaped supercapacitors. Because of the all-fiber-shaped structure of the entire system, our proposed hybridized self-charging textile system can be easily woven into electronic textiles to fabricate smart clothes to sustainably operate mobile or wearable electronics.

  17. Self-activated ultrahigh chemosensitivity of oxide thin film nanostructures for transparent sensors

    PubMed Central

    Moon, Hi Gyu; Shim, Young-Soek; Kim, Do Hong; Jeong, Hu Young; Jeong, Myoungho; Jung, Joo Young; Han, Seung Min; Kim, Jong Kyu; Kim, Jin-Sang; Park, Hyung-Ho; Lee, Jong-Heun; Tuller, Harry L.; Yoon, Seok-Jin; Jang, Ho Won

    2012-01-01

    One of the top design priorities for semiconductor chemical sensors is developing simple, low-cost, sensitive and reliable sensors to be built in handheld devices. However, the need to implement heating elements in sensor devices, and the resulting high power consumption, remains a major obstacle for the realization of miniaturized and integrated chemoresistive thin film sensors based on metal oxides. Here we demonstrate structurally simple but extremely efficient all oxide chemoresistive sensors with ~90% transmittance at visible wavelengths. Highly effective self-activation in anisotropically self-assembled nanocolumnar tungsten oxide thin films on glass substrate with indium-tin oxide electrodes enables ultrahigh response to nitrogen dioxide and volatile organic compounds with detection limits down to parts per trillion levels and power consumption less than 0.2 microwatts. Beyond the sensing performance, high transparency at visible wavelengths creates opportunities for their use in transparent electronic circuitry and optoelectronic devices with avenues for further functional convergence. PMID:22905319

  18. The Hirnantian δ13C Positive Excursion in the Nabiullino Section (South Urals)

    NASA Astrophysics Data System (ADS)

    Yakupov, R. R.; Mavrinskaya, T. M.; Smoleva, I. V.

    2018-02-01

    The upper Sandbian, Katian, and Hirnantian complexes of conodonts in the upper Ordovician section of the western slope of the Southern Urals near the village of Nabiullino were studied. The δ13C positive excursion with a maximum of 3.3‰ associated with the global Hirnantian isotopic event, HICE, was fixed for the first time. This excursion shows the beginning of the Hirnantian stage in the terrigenous-carbonate section of the upper Ordovician in the Southern Urals. It coincides with the first occurrence of the Hirnantian conodont species of Gamachignathus ensifer and the conodonts of shallow-water biophacies, Aphelognathus-Ozarkodina, reflecting the global glacio-eustatic event.

  19. Eye Movements in Darkness Modulate Self-Motion Perception.

    PubMed

    Clemens, Ivar Adrianus H; Selen, Luc P J; Pomante, Antonella; MacNeilage, Paul R; Medendorp, W Pieter

    2017-01-01

    During self-motion, humans typically move the eyes to maintain fixation on the stationary environment around them. These eye movements could in principle be used to estimate self-motion, but their impact on perception is unknown. We had participants judge self-motion during different eye-movement conditions in the absence of full-field optic flow. In a two-alternative forced choice task, participants indicated whether the second of two successive passive lateral whole-body translations was longer or shorter than the first. This task was used in two experiments. In the first ( n = 8), eye movements were constrained differently in the two translation intervals by presenting either a world-fixed or body-fixed fixation point or no fixation point at all (allowing free gaze). Results show that perceived translations were shorter with a body-fixed than a world-fixed fixation point. A linear model indicated that eye-movement signals received a weight of ∼25% for the self-motion percept. This model was independently validated in the trials without a fixation point (free gaze). In the second experiment ( n = 10), gaze was free during both translation intervals. Results show that the translation with the larger eye-movement excursion was judged more often to be larger than chance, based on an oculomotor choice probability analysis. We conclude that eye-movement signals influence self-motion perception, even in the absence of visual stimulation.

  20. Eye Movements in Darkness Modulate Self-Motion Perception

    PubMed Central

    Pomante, Antonella

    2017-01-01

    Abstract During self-motion, humans typically move the eyes to maintain fixation on the stationary environment around them. These eye movements could in principle be used to estimate self-motion, but their impact on perception is unknown. We had participants judge self-motion during different eye-movement conditions in the absence of full-field optic flow. In a two-alternative forced choice task, participants indicated whether the second of two successive passive lateral whole-body translations was longer or shorter than the first. This task was used in two experiments. In the first (n = 8), eye movements were constrained differently in the two translation intervals by presenting either a world-fixed or body-fixed fixation point or no fixation point at all (allowing free gaze). Results show that perceived translations were shorter with a body-fixed than a world-fixed fixation point. A linear model indicated that eye-movement signals received a weight of ∼25% for the self-motion percept. This model was independently validated in the trials without a fixation point (free gaze). In the second experiment (n = 10), gaze was free during both translation intervals. Results show that the translation with the larger eye-movement excursion was judged more often to be larger than chance, based on an oculomotor choice probability analysis. We conclude that eye-movement signals influence self-motion perception, even in the absence of visual stimulation. PMID:28144623

  1. Power-scaling performance of a three-dimensional tritium betavoltaic diode

    NASA Astrophysics Data System (ADS)

    Liu, Baojun; Chen, Kevin P.; Kherani, Nazir P.; Zukotynski, Stefan

    2009-12-01

    Three-dimensional diodes fabricated by electrochemical etching are exposed to tritium gas at pressures from 0.05 to 33 atm at room temperature to examine its power scaling performance. It is shown that the three-dimensional microporous structure overcomes the self-absorption limited saturation of beta flux at high tritium pressures. These results are contrasted against the three-dimensional device powered in one instance by tritium absorbed in the near surface region of the three-dimensional microporous network, and in another by a planar scandium tritide foil. These findings suggest that direct tritium occlusion in the near surface of three-dimensional diode can improve the specific power production.

  2. Hubble Space Telescope Servicing Mission 3A Rendezvous Operations

    NASA Technical Reports Server (NTRS)

    Lee, S.; Anandakrishnan, S.; Connor, C.; Moy, E.; Smith, D.; Myslinski, M.; Markley, L.; Vernacchio, A.

    2001-01-01

    The Hubble Space Telescope (HST) hardware complement includes six gas bearing, pulse rebalanced rate integrating gyros, any three of which are sufficient to conduct the science mission. After the loss of three gyros between April 1997 and April 1999 due to a known corrosion mechanism, NASA decided to split the third HST servicing mission into SM3A, accelerated to October 1999, and SM3B, scheduled for November 2001. SM3A was developed as a quick turnaround 'Launch on Need' mission to replace all six gyros. Loss of a fourth gyro in November 1999 caused HST to enter Zero Gyro Sunpoint (ZGSP) safemode, which uses sun sensors and magnetometers for attitude determination and momentum bias to maintain attitude stability during orbit night. Several instances of large attitude excursions during orbit night were observed, but ZGSP performance was adequate to provide power-positive sun pointing and to support low gain antenna communications. Body rates in ZGSP were estimated to exceed the nominal 0.1 deg/sec rendezvous limit, so rendezvous operations were restructured to utilize coarse, limited life, Retrieval Mode Gyros (RMGs) under Hardware Sunpoint (HWSP) safemode. Contingency procedures were developed to conduct the rendezvous in ZGSP in the event of RMGA or HWSP computer failure. Space Shuttle Mission STS-103 launched on December 19, 1999 after a series of weather and Shuttle-related delays. After successful rendezvous and grapple under HWSP/RMGA, the crew changed out all six gyros. Following deploy and systems checkout, HST returned to full science operations.

  3. Power-controlled transition from standard to negative refraction in reorientational soft matter.

    PubMed

    Piccardi, Armando; Alberucci, Alessandro; Kravets, Nina; Buchnev, Oleksandr; Assanto, Gaetano

    2014-11-25

    Refraction at a dielectric interface can take an anomalous character in anisotropic crystals, when light is negatively refracted with incident and refracted beams emerging on the same side of the interface normal. In soft matter subject to reorientation, such as nematic liquid crystals, the nonlinear interaction with light allows tuning of the optical properties. We demonstrate that in such material a beam of light can experience either positive or negative refraction depending on input power, as it can alter the spatial distribution of the optic axis and, in turn, the direction of the energy flow when traveling across an interface. Moreover, the nonlinear optical response yields beam self-focusing and spatial localization into a self-confined solitary wave through the formation of a graded-index waveguide, linking the refractive transition to power-driven readdressing of copolarized guided-wave signals, with a number of output ports not limited by diffraction.

  4. Multicultural Group Work on Field Excursions to Promote Student Teachers' Intercultural Competence

    ERIC Educational Resources Information Center

    Brendel, Nina; Aksit, Fisun; Aksit, Selahattin; Schrüfer, Gabriele

    2016-01-01

    As a response to the intercultural challenges of Geography Education, this study seeks to determine factors fostering intercultural competence of student teachers. Based on a one-week multicultural field excursion of eight German and eight Turkish students in Kayseri (Turkey) on Education for Sustainable Development, we used qualitative interviews…

  5. Enabling the Development of Student Teacher Professional Identity through Vicarious Learning during an Educational Excursion

    ERIC Educational Resources Information Center

    Steenekamp, Karen; van der Merwe, Martyn; Mehmedova, Aygul Salieva

    2018-01-01

    This paper explores the views of student teachers who were provided vicarious learning opportunities during an educational excursion, and how the learning enabled them to develop their teacher professional identity. This qualitative research study, using a social-constructivist lens highlights how vicarious learning influenced student teachers'…

  6. Positive self-statements: power for some, peril for others.

    PubMed

    Wood, Joanne V; Perunovic, W Q Elaine; Lee, John W

    2009-07-01

    Positive self-statements are widely believed to boost mood and self-esteem, yet their effectiveness has not been demonstrated. We examined the contrary prediction that positive self-statements can be ineffective or even harmful. A survey study confirmed that people often use positive self-statements and believe them to be effective. Two experiments showed that among participants with low self-esteem, those who repeated a positive self-statement ("I'm a lovable person") or who focused on how that statement was true felt worse than those who did not repeat the statement or who focused on how it was both true and not true. Among participants with high self-esteem, those who repeated the statement or focused on how it was true felt better than those who did not, but to a limited degree. Repeating positive self-statements may benefit certain people, but backfire for the very people who "need" them the most.

  7. 75 FR 6426 - Self-Regulatory Organizations; NASDAQ OMX PHLX, Inc.; Notice of Filing of Proposed Rule Change To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-09

    ... on a first-come/first-serve basis. Should available cabinet inventory shrink to 40 cabinets or less... be limited to a maximum power level of 5kW. Should available cabinet inventory shrink to zero, the...

  8. Non-invasive measurement of pulse wave velocity using transputer-based analysis of Doppler flow audio signals.

    PubMed

    Stewart, W R; Ramsey, M W; Jones, C J

    1994-08-01

    A system for the measurement of arterial pulse wave velocity is described. A personal computer (PC) plug-in transputer board is used to process the audio signals from two pocket Doppler ultrasound units. The transputer is used to provide a set of bandpass digital filters on two channels. The times of excursion of power through thresholds in each filter are recorded and used to estimate the onset of systolic flow. The system does not require an additional spectrum analyser and can work in real time. The transputer architecture provides for easy integration into any wider physiological measurement system.

  9. Predictive momentum management for the Space Station

    NASA Technical Reports Server (NTRS)

    Hatis, P. D.

    1986-01-01

    Space station control moment gyro momentum management is addressed by posing a deterministic optimization problem with a performance index that includes station external torque loading, gyro control torque demand, and excursions from desired reference attitudes. It is shown that a simple analytic desired attitude solution exists for all axes with pitch prescription decoupled, but roll and yaw coupled. Continuous gyro desaturation is shown to fit neatly into the scheme. Example results for pitch axis control of the NASA power tower Space Station are shown based on predictive attitude prescription. Control effector loading is shown to be reduced by this method when compared to more conventional momentum management techniques.

  10. Femtosecond fiber CPA system based on picosecond master oscillator and power amplifier with CCC fiber.

    PubMed

    Želudevičius, J; Danilevičius, R; Viskontas, K; Rusteika, N; Regelskis, K

    2013-03-11

    Results of numerical and experimental investigations of the simple fiber CPA system seeded by nearly bandwidth-limited pulses from the picosecond oscillator are presented. We utilized self-phase modulation in a stretcher fiber to broaden the pulse spectrum and dispersion of the fiber to stretch pulses in time. During amplification in the ytterbium-doped CCC fiber, gain-shaping and self-phase modulation effects were observed, which improved pulse compression with a bulk diffraction grating compressor. After compression with spectral filtering, pulses with the duration of 400 fs and energy as high as 50 µJ were achieved, and the output beam quality was nearly diffraction-limited.

  11. Nonlinear guiding of picosecond CO2 laser pulses in atmosphere(Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Tochitsky, Sergei

    2017-05-01

    During the last 20 years much attention has been given to the study of propagation of short intense laser pulses for which the peak power exceeds the critical power of self-focusing, Pcr. For a laser power P < Pcr, a dynamic equilibrium between the Kerr self-focusing, diffraction and defocusing caused by laser-ionized plasma result in the production of a high intensity laser filament in air within which a variety of nonlinear optical phenomena are observed. However, research in the 0.8-1 μm range so far has shown a fundamental limitation of guided energy to a few mJ transported within an 100 μm single channel. A long-wavelength, 0 10 μm CO2 laser is a promising candidate for nonlinear guiding because expected high Pcr values according to the modeling should allow for the increase of energy (and therefore power) in a self-guided beam from mJ (GW) to few Joules (TW). During the last decade a significant progress has been achieved in amplification of picosecond pulses to terawatt and recently to <10 TW power level at UCLA and ATF BNL. Such powerful 10 μm lasers open possibility for nonlinear propagation studies in an atmospheric window with high transmission. As a natural first step in a our program on picosecond CO2 laser filamentation, we have made first measurements of Kerr coefficients of air and air constituents around 10 μm. We also undertook direct measurements of n2 of air by analyzing nonlinear self-focusing in air using a 3 ps, 600 GW pulses of the BNL CO2 laser.

  12. A field data assessment of contemporary models of beach cusp formation

    USGS Publications Warehouse

    Allen, J.R.; Psuty, N.P.; Bauer, B.O.; Carter, R.W.G.

    1996-01-01

    Cusp formation was observed during an instrumented, daily profiled, time series of a reflective beach in Canaveral National Seashore, Florida on January 5, 1988. The monitored cusp embayment formed by erosion of the foreshore and the cusp series had a mean spacing of approximately 28 m. During this time, inshore fluid flows were dominated by two standing edge waves at frequencies of 0.06 Hz (primary) and 0.035 Hz (secondary) whereas incident waves were broadbanded at 0.12-0.16 Hz. Directly measured flows (and indirectly estimated swash excursion) data support both the standing wave subharmonic model and the self-organization model of cusp formation in this study.

  13. Evaluation of PS 212 Coatings Under Boundary Lubrication Conditions with an Ester-based Oil to 300 C

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Loomis, William R.; Dellacorte, Christopher

    1994-01-01

    High friction and wear of turbine engine components occur during high temperature excursions above the oxidation threshold of the liquid lubricant. This paper reports on research to study the use of a high temperature self lubricating coating, PS 212 for back-up lubrication in the event of failure of the liquid lubricant. Pin on disk tests were performed under dry and boundary-lubricated conditions at disk temperatures up to 300 C. The liquid lubricant was a formulated polyol ester qualified under MIL L-23699. At test temperatures above the oil's thermal degradation level, the use of PS 212 reduced wear, providing a back-up lubricant effect.

  14. Self-phase-modulation induced spectral broadening in silicon waveguides

    NASA Astrophysics Data System (ADS)

    Boyraz, Ozdal; Indukuri, Tejaswi; Jalali, Bahram

    2004-03-01

    The prospect for generating supercontinuum pulses on a silicon chip is studied. Using ~4ps optical pulses with 2.2GW/cm2 peak power, a 2 fold spectral broadening is obtained. Theoretical calculations, that include the effect of two-photon-absorption, indicate up to 5 times spectral broadening is achievable at 10x higher peak powers. Representing a nonlinear loss mechanism at high intensities, TPA limits the maximum optical bandwidth that can be generated.

  15. Self-phase-modulation induced spectral broadening in silicon waveguides.

    PubMed

    Boyraz, Ozdal; Indukuri, Tejaswi; Jalali, Bahram

    2004-03-08

    The prospect for generating supercontinuum pulses on a silicon chip is studied. Using ~4ps optical pulses with 2.2GW/cm(2) peak power, a 2 fold spectral broadening is obtained. Theoretical calculations, that include the effect of two-photon-absorption, indicate up to 5 times spectral broadening is achievable at 10x higher peak powers. Representing a nonlinear loss mechanism at high intensities, TPA limits the maximum optical bandwidth that can be generated.

  16. Exploration of Self-Regulation in the Natural Swimming of the Paramecium’s Cilium

    DTIC Science & Technology

    2012-02-01

    aquatic environments. These animals propel themselves, albeit with limited maneuverability, by the synchronous motion of numerous tiny cilia...microtubule pairs are the source of cilium hardness during the power stroke ; there is a critical phase near the end of the power stroke where one cross...return stroke ; therefore, in each beat cycle, there must be a reattachment process of the cross-bridge links and re-hardening of the cilium during the

  17. Strong Electron Self-Cooling in the Cold-Electron Bolometers Designed for CMB Measurements

    NASA Astrophysics Data System (ADS)

    Kuzmin, L. S.; Pankratov, A. L.; Gordeeva, A. V.; Zbrozhek, V. O.; Revin, L. S.; Shamporov, V. A.; Masi, S.; de Bernardis, P.

    2018-03-01

    We have realized cold-electron bolometers (CEB) with direct electron self-cooling of the nanoabsorber by SIN (Superconductor-Insulator-Normal metal) tunnel junctions. This electron self-cooling acts as a strong negative electrothermal feedback, improving noise and dynamic properties. Due to this cooling the photon-noise-limited operation of CEBs was realized in array of bolometers developed for the 345 GHz channel of the OLIMPO Balloon Telescope in the power range from 10 pW to 20 pW at phonon temperature Tph =310 mK. The negative electrothermal feedback in CEB is analogous to TES but instead of artificial heating we use cooling of the absorber. The high efficiency of the electron self-cooling to Te =100 mK without power load and to Te=160 mK under power load is achieved by: - a very small volume of the nanoabsorber (0.02 μm3) and a large area of the SIN tunnel junctions, - effective removal of hot quasiparticles by arranging double stock at both sides of the junctions and close position of the normal metal traps, - self-protection of the 2D array of CEBs against interferences by dividing them between N series CEBs (for voltage interferences) and M parallel CEBs (for current interferences), - suppression of Andreev reflection by a thin layer of Fe in the AlFe absorber. As a result even under high power load the CEBs are working at electron temperature Te less than Tph . To our knowledge, there is no analogue in the bolometers technology in the world for bolometers working at electron temperature colder than phonon temperature.

  18. Emergent inequality and self-organized social classes in a network of power and frustration

    DOE PAGES

    Mahault, Benoit; Saxena, Avadh; Nisoli, Cristiano

    2017-02-17

    We propose a simple agent-based model on a network to conceptualize the allocation of limited wealth among more abundant expectations at the interplay of power, frustration, and initiative. Concepts imported from the statistical physics of frustrated systems in and out of equilibrium allow us to compare subjective measures of frustration and satisfaction to collective measures of fairness in wealth distribution, such as the Lorenz curve and the Gini index. We find that a completely libertarian, law-of-the-jungle setting, where every agent can acquire wealth from or lose wealth to anybody else invariably leads to a complete polarization of the distribution ofmore » wealth vs. opportunity. This picture is however dramatically ameliorated when hard constraints are imposed over agents in the form of a limiting network of transactions. There, an out of equilibrium dynamics of the networks, based on a competition between power and frustration in the decision-making of agents, leads to network coevolution. The ratio of power and frustration controls different dynamical regimes separated by kinetic transitions and characterized by drastically different values of equality. It also leads, for proper values of social initiative, to the emergence of three self-organized social classes, lower, middle, and upper class. Their dynamics, which appears mostly controlled by the middle class, drives a cyclical regime of dramatic social changes.« less

  19. Emergent inequality and self-organized social classes in a network of power and frustration

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

    Mahault, Benoit; Saxena, Avadh; Nisoli, Cristiano

    We propose a simple agent-based model on a network to conceptualize the allocation of limited wealth among more abundant expectations at the interplay of power, frustration, and initiative. Concepts imported from the statistical physics of frustrated systems in and out of equilibrium allow us to compare subjective measures of frustration and satisfaction to collective measures of fairness in wealth distribution, such as the Lorenz curve and the Gini index. We find that a completely libertarian, law-of-the-jungle setting, where every agent can acquire wealth from or lose wealth to anybody else invariably leads to a complete polarization of the distribution ofmore » wealth vs. opportunity. This picture is however dramatically ameliorated when hard constraints are imposed over agents in the form of a limiting network of transactions. There, an out of equilibrium dynamics of the networks, based on a competition between power and frustration in the decision-making of agents, leads to network coevolution. The ratio of power and frustration controls different dynamical regimes separated by kinetic transitions and characterized by drastically different values of equality. It also leads, for proper values of social initiative, to the emergence of three self-organized social classes, lower, middle, and upper class. Their dynamics, which appears mostly controlled by the middle class, drives a cyclical regime of dramatic social changes.« less

  20. Emergent inequality and self-organized social classes in a network of power and frustration

    PubMed Central

    Mahault, Benoit; Saxena, Avadh

    2017-01-01

    We propose a simple agent-based model on a network to conceptualize the allocation of limited wealth among more abundant expectations at the interplay of power, frustration, and initiative. Concepts imported from the statistical physics of frustrated systems in and out of equilibrium allow us to compare subjective measures of frustration and satisfaction to collective measures of fairness in wealth distribution, such as the Lorenz curve and the Gini index. We find that a completely libertarian, law-of-the-jungle setting, where every agent can acquire wealth from or lose wealth to anybody else invariably leads to a complete polarization of the distribution of wealth vs. opportunity. This picture is however dramatically ameliorated when hard constraints are imposed over agents in the form of a limiting network of transactions. There, an out of equilibrium dynamics of the networks, based on a competition between power and frustration in the decision-making of agents, leads to network coevolution. The ratio of power and frustration controls different dynamical regimes separated by kinetic transitions and characterized by drastically different values of equality. It also leads, for proper values of social initiative, to the emergence of three self-organized social classes, lower, middle, and upper class. Their dynamics, which appears mostly controlled by the middle class, drives a cyclical regime of dramatic social changes. PMID:28212440

  1. Emergent inequality and self-organized social classes in a network of power and frustration.

    PubMed

    Mahault, Benoit; Saxena, Avadh; Nisoli, Cristiano

    2017-01-01

    We propose a simple agent-based model on a network to conceptualize the allocation of limited wealth among more abundant expectations at the interplay of power, frustration, and initiative. Concepts imported from the statistical physics of frustrated systems in and out of equilibrium allow us to compare subjective measures of frustration and satisfaction to collective measures of fairness in wealth distribution, such as the Lorenz curve and the Gini index. We find that a completely libertarian, law-of-the-jungle setting, where every agent can acquire wealth from or lose wealth to anybody else invariably leads to a complete polarization of the distribution of wealth vs. opportunity. This picture is however dramatically ameliorated when hard constraints are imposed over agents in the form of a limiting network of transactions. There, an out of equilibrium dynamics of the networks, based on a competition between power and frustration in the decision-making of agents, leads to network coevolution. The ratio of power and frustration controls different dynamical regimes separated by kinetic transitions and characterized by drastically different values of equality. It also leads, for proper values of social initiative, to the emergence of three self-organized social classes, lower, middle, and upper class. Their dynamics, which appears mostly controlled by the middle class, drives a cyclical regime of dramatic social changes.

  2. Dating the Laschamp Excursion: Why Speleothems are Valuable Tools for Constraining the Timing and Duration of Short-Lived Geomagnetic Events

    NASA Astrophysics Data System (ADS)

    Lascu, I.; Feinberg, J. M.; Dorale, J. A.; Cheng, H.; Edwards, R. L.

    2015-12-01

    Short-lived geomagnetic events are reflections of geodynamo behavior at small length scales. A rigorous documentation of the anatomy, timing, duration, and frequency of centennial-to-millennial scale geomagnetic events can be invaluable for theoretical and numerical geodynamo models, and for the understanding the finer dynamics of the Earth's core. A critical ingredient for characterizing such geomagnetic instabilities are tightly constrained age models that enable high-resolution magnetostratigraphies. Here we focus on a North American speleothem geomagnetic record of the Laschamp excursion, which was the first geomagnetic excursion recognized and described in the paleomagnetic record, and remains the most studied event of its kind. The geological significance of the Laschamp lies chiefly in the fact that it constitutes a global time-synchronous geochronological marker. The Laschamp excursion occurred around the time of the demise of Homo neanderthalensis, in conjunction with high-amplitude, rapid climatic oscillations leading into the Last Glacial Maximum, and precedes a major supervolcano eruption in the Mediterranean. Thus, the precise determination of the timing and duration of the Laschamp would help in elucidating major scientific questions situated at the intersection of geology, paleoclimatology, and anthropology. Here we present a geomagnetic record from a stalagmite collected in Crevice Cave, Missouri, which we have dated using a combination of high-precision 230Th ages and annual layer counting using confocal microscopy. We have found a maximum duration for the Laschamp that spans the interval 42,250-39,700 years BP, and an age of 41,100 ± 350 years BP for the height of the excursion. During this period relative paleointensity decreased by an order of magnitude and the virtual geomagnetic pole was located at southerly latitudes. Our chronology provides the first robust bracketing for the Laschamp excursion, and improves on previous age determinations based on 40Ar/39Ar dating of lava flows, and orbitally-tuned sedimentary and ice-core records.

  3. Glycemic excursions are positively associated with changes in duration of asymptomatic hypoglycemia after treatment intensification in patients with type 2 diabetes.

    PubMed

    Wang, Jun-Sing; Lee, I-Te; Lee, Wen-Jane; Lin, Shi-Dou; Su, Shih-Li; Tu, Shih-Te; Tseng, Yao-Hsien; Lin, Shih-Yi; Sheu, Wayne Huey-Herng

    2016-03-01

    The aim of this study was to examine the association between glycemic excursions and duration of hypoglycemia after treatment intensification in patients with type 2 diabetes (T2D). Patients with T2D on oral anti-diabetes drug (OAD) with glycated hemoglobin (HbA1c) of 7.0-11.0% were switched to metformin monotherapy (500 mg thrice daily) for 8 weeks, followed by randomization to either glibenclamide or acarbose as add-on treatment for 16 weeks. Glycemic excursions were assessed as mean amplitude of glycemic excursions (MAGE) with 72-h ambulatory continuous glucose monitoring (CGM) before randomization and at the end of study. Hypoglycemia was defined as sensor glucose level of less than 60 mg/dl in two or more consecutive readings from CGM. A total of 50 patients (mean age 53.5 ± 8.2 years, male 48%, mean baseline HbA1c 8.4 ± 1.2%) were analyzed. Duration of hypoglycemia significantly increased after treatment with glibenclamide (from 5.5 ± 13.8 to 18.8 ± 35.8 min/day, p=0.041), but not with acarbose (from 2.9 ± 10.9 to 14.7 ± 41.9 min/day, p=0.114). Post treatment MAGE was positively associated with change from baseline in duration of hypoglycemia after treatment with either glibenclamide (β coefficient 0.345, p=0.036) or acarbose (β coefficient 0.674, p=0.046). The association remained significant after multivariate adjustment (p<0.05 for all models). Post treatment glycemic excursions are associated with changes in duration of hypoglycemia after treatment intensification with OAD in patients with T2D. Glycemic excursions should be an important treatment target for T2D to reduce the risk of hypoglycemia. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Disk Disruptions and X-ray Intensity Excursions in Cyg X-2, LMC X-3 and Cyg X-3

    NASA Astrophysics Data System (ADS)

    Boyd, P. T.; Smale, A. P.

    2001-05-01

    The RXTE All Sky Monitor soft X-ray light curves of many X-ray binaries show long-term intensity variations (a.k.a "superorbital periodicities") that have been ascribed to precession of a warped, tilted accretion disk around the X-ray source. We have found that the excursion times between X-ray minima in Cyg X-2 can be characterized as a series of integer multiples of the 9.8 binary orbital period, (as opposed to the previously reported stable 77.7 day single periodicity, or a single modulation whose period changes slowly with time). While the data set is too short for a proper statistical analysis, it is clear that the length of any given intensity excursion cannot be used to predict the next (integer) excursion length in the series. In the black hole candidate system LMC X-3, the excursion times are shown to be related to each other by rational fractions. We find that the long term light curve of the unusual galactic X-ray jet source Cyg X-3 can also be described as a series of intensity excursions related to each other by integer multiples of a fundamental underlying clock. In the latter cases, the clock is apparently not related to the known binary periods. A unified physical model, involving both an inclined accretion disk and a fixed-probability disk disruption mechanism is presented, and compared with three-body scattering results. Each time the disk passes through the orbital plane it experiences a fixed probability P that it will disrupt. This model has testable predictions---the distribution of integers should resemble that of an atomic process with a characteristic half life. Further analysis can support or refute the model, and shed light on what system parameters effectively set the value of P.

  5. Knee Joint Contact Mechanics during Downhill Gait and its Relationship with Varus/Valgus Motion and Muscle Strength in Patients with Knee Osteoarthritis

    PubMed Central

    Farrokhi, Shawn; Voycheck, Carrie A.; Gustafson, Jonathan A.; Fitzgerald, G. Kelley; Tashman, Scott

    2015-01-01

    Objective The objective of this exploratory study was to evaluate tibiofemoral joint contact point excursions and velocities during downhill gait and assess the relationship between tibiofemoral joint contact mechanics with frontal-plane knee joint motion and lower extremity muscle weakness in patients with knee osteoarthritis (OA). Methods Dynamic stereo X-ray was used to quantify tibiofemoral joint contact mechanics and frontal-plane motion during the loading response phase of downhill gait in 11 patients with knee OA and 11 control volunteers. Quantitative testing of the quadriceps and the hip abductor muscles was also performed. Group differences in contact mechanics and frontal-plane motion excursions were compared using analysis of covariance with adjustments for body mass index. Differences in strength were compared using independent sample t-tests. Additionally, linear associations between contact mechanics with frontal-plane knee motion and muscle strength were evaluated using Pearson's correlation coefficients. Results Patients with knee OA demonstrated larger medial/lateral joint contact point excursions (p<0.02) and greater heel-strike joint contact point velocities (p<0.05) for the medial and lateral compartments compared to the control group. The peak medial/lateral joint contact point velocity of the medial compartment was also greater for patients with knee OA compared to their control counterparts (p=0.02). Additionally, patients with knee OA demonstrated significantly increased frontal-plane varus motion excursions (p<0.01) and greater quadriceps and hip abductor muscle weakness (p=0.03). In general, increased joint contact point excursions and velocities in patients with knee OA were linearly associated with greater frontal-plane varus motion excursions (p<0.04) but not with quadriceps or hip abductor strength. Conclusion Altered contact mechanics in patients with knee OA may be related to compromised frontal-plane joint stability but not with deficits in muscle strength. PMID:27030846

  6. Nateglinide and acarbose are comparably effective reducers of postprandial glycemic excursions in chinese antihyperglycemic agent-naive subjects with type 2 diabetes.

    PubMed

    Zhou, Jian; Li, Hong; Zhang, Xiuzhen; Peng, Yongde; Mo, Yifei; Bao, Yuqian; Jia, Weiping

    2013-06-01

    Recent studies have identified postprandial glycemic excursions as risk factors for diabetes complications. This study aimed to compare the effects of nateglinide and acarbose treatments on postprandial glycemic excursions in Chinese subjects with type 2 diabetes. This was a multicenter, open-label, randomized, active-controlled, parallel-group study. One hundred three antihyperglycemic agent-naive subjects with type 2 diabetes (hemoglobin A1c range, 6.5-9.0%) were prospectively recruited from four hospitals in China. The intervention was nateglinide (120 mg three times a day) or acarbose (50 mg three times a day) therapy for 2 weeks. A continuous glucose monitoring system was used to calculate the incremental area under the curve of postprandial blood glucose (AUCpp), the incremental glucose peak (IGP), mean amplitude of glycemic excursions, SD of blood glucose, the mean of daily differences, and 24-h mean blood glucose (MBG). Subjects' serum glycated albumin and the plasma insulin levels were also analyzed. Both agents caused significant reductions on AUCpp and IGP. Similarly, both treatment groups showed significant improvements in the intra- and interday glycemic excursions, as well as the 24-h MBG and serum glycated albumin compared with baseline (P<0.001). However, neither of the agents produced a significantly better effect (P>0.05). Moreover, the nateglinide-treated group had significantly increased insulin levels at 30 min and at 120 min after a standard meal compared with baseline, whereas the acarbose-treated group decreased. No serious adverse events occurred in either group. The rates of hypoglycemic episodes were comparable in the two groups, and no severe hypoglycemic episode occurred in either group. Nateglinide and acarbose were comparably effective in reducing postprandial glycemic excursions in antihyperglycemic agent-naive Chinese patients with type 2 diabetes, possibly through different pathophysiological mechanisms.

  7. Is the Earth's magnetic field heading for a flip? Hints from the past

    NASA Astrophysics Data System (ADS)

    Laj, C. E.; Kissel, C.

    2017-12-01

    The magnitude of the Earth's dipole magnetic field has decreased significantly over the last centuries at a mean rate of 16 nT/y. This decrease, which correlates with the growth of the South Atlantic Anomaly (SAA) therefore occurs at a rate which is about 10 times larger than expected from a free Ohmic decay process. This situation has led to speculations that an attempt to a reversal or a geomagnetic excursion might be underway. We investigate this hypothesis by examining past geomagnetic instabilities, focussing on the well documented Laschamp and Mono Lake excursions. We have selected high accumulation sedimentary records with very precise age model, leading to unprecedented temporal resolution, and accurate calibration of RPI between 20 and 75 kyr B.P. We also used the 10Be and 36Cl records from the Greenland ice cores. The rate of decay of the field intensity during these two excursions is virtually identical to that observed over the last centuries and much higher than that observed for another period of low intensity (around 65 kyr BP) not associated with a polarity change. Moreover, the global morphology of the Laschamp excursion obtained by Bayesian inversion (Leonhardt et al. (2009) is that reverse magnetic field patches at the core-mantle boundary are formed near the equator and then move poleward, a scenario reminiscent of that described for the present field in the litterature. Therefore, although these results from two excursions do not provide undisputable information on future evolution of the field, they show similarities with several aspects of the present-day geomagnetic field. Assuming that the dynamo processes for an eventual future instability would be similar to those of the past two excursions, we tentatively suggest that, whilst irreversible processes that will drive the geodynamo into a polarity change may have already started, some 1000 years would be needed for the directional changes to start to be significant.

  8. Nateglinide and Acarbose Are Comparably Effective Reducers of Postprandial Glycemic Excursions in Chinese Antihyperglycemic Agent–Naive Subjects with Type 2 Diabetes

    PubMed Central

    Zhou, Jian; Li, Hong; Zhang, Xiuzhen; Peng, Yongde; Mo, Yifei; Bao, Yuqian

    2013-01-01

    Abstract Background Recent studies have identified postprandial glycemic excursions as risk factors for diabetes complications. This study aimed to compare the effects of nateglinide and acarbose treatments on postprandial glycemic excursions in Chinese subjects with type 2 diabetes. Subjects and Methods This was a multicenter, open-label, randomized, active-controlled, parallel-group study. One hundred three antihyperglycemic agent–naive subjects with type 2 diabetes (hemoglobin A1c range, 6.5–9.0%) were prospectively recruited from four hospitals in China. The intervention was nateglinide (120 mg three times a day) or acarbose (50 mg three times a day) therapy for 2 weeks. A continuous glucose monitoring system was used to calculate the incremental area under the curve of postprandial blood glucose (AUCpp), the incremental glucose peak (IGP), mean amplitude of glycemic excursions, SD of blood glucose, the mean of daily differences, and 24-h mean blood glucose (MBG). Subjects' serum glycated albumin and the plasma insulin levels were also analyzed. Results Both agents caused significant reductions on AUCpp and IGP. Similarly, both treatment groups showed significant improvements in the intra- and interday glycemic excursions, as well as the 24-h MBG and serum glycated albumin compared with baseline (P<0.001). However, neither of the agents produced a significantly better effect (P>0.05). Moreover, the nateglinide-treated group had significantly increased insulin levels at 30 min and at 120 min after a standard meal compared with baseline, whereas the acarbose-treated group decreased. No serious adverse events occurred in either group. The rates of hypoglycemic episodes were comparable in the two groups, and no severe hypoglycemic episode occurred in either group. Conclusions Nateglinide and acarbose were comparably effective in reducing postprandial glycemic excursions in antihyperglycemic agent–naive Chinese patients with type 2 diabetes, possibly through different pathophysiological mechanisms. PMID:23631607

  9. Alarms based on real-time sensor glucose values alert patients to hypo- and hyperglycemia: the guardian continuous monitoring system.

    PubMed

    Bode, Bruce; Gross, Kenneth; Rikalo, Nancy; Schwartz, Sherwyn; Wahl, Timothy; Page, Casey; Gross, Todd; Mastrototaro, John

    2004-04-01

    The purposes of this study were to demonstrate the accuracy and effectiveness of the Guardian Continuous Monitoring System (Medtronic MiniMed, Northridge, California) and to demonstrate that the application of real-time alarms to continuous monitoring alerts users to hypo and hyperglycemia and reduces excursions in people with diabetes. A total of 71 subjects with type 1 diabetes, mean hemoglobin A1c of 7.6 +/- 1.1%, age 44.0 +/- 11.4 years, and duration of diabetes 23.6 +/- 10.6 years were enrolled in this two-period, randomized, multicenter study. Subjects were randomized into either an Alert group or a Control group. The accuracy of the Guardian was evaluated by treating the study data as a single-sample correlational design. Effectiveness of the Guardian alerts was evaluated by comparing the Alert group with the Control group. The mean (median) absolute relative error between home blood glucose meter readings and sensor values was 21.3% (17.3%), and the Guardian, on average, read 12.8 mg/dL below the concurrent home blood glucose meter readings. The hypoglycemia alert was able to distinguished glucose values < or =70 mg/dL with 67% sensitivity, 90% specificity, and 47% false alerts. The hyperglycemia alert showed a similar ability to detect sensor values > or =250 mg/dL with 63% sensitivity, 97% specificity, and 19% false alerts. The Alert group demonstrated a median decrease in the duration of hypoglycemic excursions (-27.8 min) that was significantly greater than the median decrease in the duration of hypoglycemic excursions in the Control group (-4.5 min) (P = 0.03). A marginally significant increase in the frequency of hyperglycemic excursions (P = 0.07) between Period 1 and Period 2 was accompanied by a decrease of 9.6 min in the duration of hyperglycemic excursions in the Alert group. Glucose measurements differ between blood samples taken from the finger and interstitial fluid, especially when levels are changing rapidly; however, these results demonstrate that the Guardian is reasonably accurate while performing continuous glucose monitoring. The subjects' responses to hypoglycemia alerts resulted in a significant reduction in the duration of hypoglycemic excursions; however, overtreating hypoglycemia may have resulted in a marginally significant increase in the frequency of hyperglycemic excursions.

  10. The influence of knee alignment on lower extremity kinetics during squats.

    PubMed

    Slater, Lindsay V; Hart, Joseph M

    2016-12-01

    The squat is an assessment of lower extremity alignment during movement, however there is little information regarding altered joint kinetics during poorly performed squats. The purpose of this study was to examine changes in joint kinetics and power from altered knee alignment during a squat. Thirty participants completed squats while displacing the knee medially, anteriorly, and with neutral alignment (control). Sagittal and frontal plane torques at the ankle, knee, and hip were altered in the descending and ascending phase of the squat in both the medial and anterior malaligned squat compared to the control squat. Ankle and trunk power increased and hip power decreased in the medial malaligned squat compared to the control squat. Ankle, knee, and trunk power increased and hip power decreased in the anterior malaligned squat compared to the control squat. Changes in joint torques and power during malaligned squats suggest that altered knee alignment increases ankle and trunk involvement to execute the movement. Increased anterior knee excursion during squatting may also lead to persistent altered loading of the ankle and knee. Sports medicine professionals using the squat for quadriceps strengthening must consider knee alignment to reduce ankle and trunk involvement during the movement. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Passive control of temperature excursion and uniformity in high-energy Li-ion battery packs at high current and ambient temperature

    NASA Astrophysics Data System (ADS)

    Kizilel, R.; Lateef, A.; Sabbah, R.; Farid, M. M.; Selman, J. R.; Al-Hallaj, S.

    A strategy for portable high-power applications with a controlled thermal environment has been developed and has demonstrated the advantage of using the novel phase change material (PCM) thermal management systems over conventional active cooling systems. A passive thermal management system using PCM for Li-ion batteries is tested for extreme conditions, such as ambient temperature of 45 °C and discharge rate of 2.08 C-rate (10 A). Contrary to Li-ion packs without thermal management system, high-energy packs with PCM are discharged safely at high currents and degrading rate of capacity of the Li-ion packs lowered by half. Moreover, the compactness of the packs not only decreases the volume occupied by the packs and its associated complex cooling system, but also decreases the total weight for large power application.

  12. NIRS-SPM: statistical parametric mapping for near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Tak, Sungho; Jang, Kwang Eun; Jung, Jinwook; Jang, Jaeduck; Jeong, Yong; Ye, Jong Chul

    2008-02-01

    Even though there exists a powerful statistical parametric mapping (SPM) tool for fMRI, similar public domain tools are not available for near infrared spectroscopy (NIRS). In this paper, we describe a new public domain statistical toolbox called NIRS-SPM for quantitative analysis of NIRS signals. Specifically, NIRS-SPM statistically analyzes the NIRS data using GLM and makes inference as the excursion probability which comes from the random field that are interpolated from the sparse measurement. In order to obtain correct inference, NIRS-SPM offers the pre-coloring and pre-whitening method for temporal correlation estimation. For simultaneous recording NIRS signal with fMRI, the spatial mapping between fMRI image and real coordinate in 3-D digitizer is estimated using Horn's algorithm. These powerful tools allows us the super-resolution localization of the brain activation which is not possible using the conventional NIRS analysis tools.

  13. Self-Powered Wireless Smart Sensor Node Enabled by an Ultrastable, Highly Efficient, and Superhydrophobic-Surface-Based Triboelectric Nanogenerator.

    PubMed

    Zhao, Kun; Wang, Zhong Lin; Yang, Ya

    2016-09-27

    Wireless sensor networks will be responsible for a majority of the fast growth in intelligent systems in the next decade. However, most of the wireless smart sensor nodes require an external power source such as a Li-ion battery, where the labor cost and environmental waste issues of replacing batteries have largely limited the practical applications. Instead of using a Li-ion battery, we report an ultrastable, highly efficient, and superhydrophobic-surface-based triboelectric nanogenerator (TENG) to scavenge wind energy for sustainably powering a wireless smart temperature sensor node. There is no decrease in the output voltage and current of the TENG after continuous working for about 14 h at a wind speed of 12 m/s. Through a power management circuit, the TENG can deliver a constant output voltage of 3.3 V and a pulsed output current of about 100 mA to achieve highly efficient energy storage in a capacitor. A wireless smart temperature sensor node can be sustainably powered by the TENG for sending the real-time temperature data to an iPhone under a working distance of 26 m, demonstrating the feasibility of the self-powered wireless smart sensor networks.

  14. Technical feasibility of an ROV with on-board power

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

    Sayer, P.; Bo, L.

    1994-12-31

    An ROI`s electric power, control and communication signals are supplied from a surface ship or platform through an umbilical cable. Though cable design has evolved steadily, there are still severe limitations such as heavy weight and cost. It is well known that the drag imposed by the cable limits the operational range of the ROV in deep water. On the other hand, a cable-free AUV presents problems in control, communication and transmission of data. Therefore, an ROV with on-board and small-diameter cable could offer both a large operating range (footprint) and real-time control. This paper considers the feasibility of suchmore » an ROV with on-board power, namely a Self-Powered ROV (SPROV). The selection of possible power sources is first discussed before comparing the operational performance of an SPROV against a conventional ROV. It is demonstrated how an SPROV with a 5mm diameter tether offers a promising way forward, with on-board power of up to 40 kW over 24 hours. In water depths greater than 50m the reduced drag of the SPROV tether is very advantageous.« less

  15. How to Individualize Mathematics Successfully: With Materials for Implementation.

    ERIC Educational Resources Information Center

    Vinskey, Mildred L.

    Presented is a method for individualizing mathematics which utilizes the "Learning Activities Package" (LAP). LAP is a self-contained unit based on specific behavioral objectives which contains a pretest, a posttest, examples, explanations, and activities. The topics covered include but are not limited to: multiplication and division by powers of…

  16. Group Identity, Deliberative Democracy and Diversity in Education

    ERIC Educational Resources Information Center

    Fraser-Burgess, Sheron

    2012-01-01

    Democratic deliberation places the burden of self-governance on its citizens to provide mutual justifying reasons (Gutmann & Thompson, 1996). This article concerns the limiting effect that group identity has on the efficacy of democratic deliberation for equality in education. Under conditions of a powerful majority, deliberation can be repressive…

  17. Students' Long-Term Memories from an Ecology Field Excursion: Retelling a Narrative as an Interplay between Implicit and Explicit Memories

    ERIC Educational Resources Information Center

    Stolpe, Karin; Bjorklund, Lars

    2013-01-01

    This study aims to investigate the science content remembered by biology students 6 and 12 months after an ecology excursion. The students' memories were tested during a stimulated recall interview. The authors identified three different types of memories: "recall," "recognition" and "narratives." The "dual…

  18. Analysis of occupant kinematics and dynamics in nearside oblique impacts.

    PubMed

    López-Valdés, F J; Juste-Lorente, O; Maza-Frechin, M; Pipkorn, B; Sunnevang, C; Lorente, A; Aso-Vizan, A; Davidsson, J

    2016-09-01

    The objective of this article is to analyze the kinematics and dynamics of restrained postmortem human surrogates (PMHS) exposed to a nearside oblique impact and the injuries that were found after the tests. Three male PMHS of similar age (64 ± 4 years) and anthropometry (weight: 61 ± 9.6 kg; stature: 172 ± 2.7 cm) were exposed to a 30° nearside oblique impact at 34 km/h. The test fixture approximated the seating position of a front seat occupant. A rigid seat was designed to match the pelvic displacement in a vehicle seat. Surrogates were restrained by a 3-point seat belt consisting of a 2 kN pretensioner (PT), 4.5 kN force-limiting shoulder belt, and a 3.5 kN PT lap belt. The shoulder belt PT was not fired in one of the tests. Trajectories of the head, shoulder, and hip joint (bilaterally) were recorded at 1,000 Hz by a 3D motion capture system. The 3D acceleration and angular rate of the head, T1, and pelvis, and the 3D acceleration of selected spinal locations was measured at 10,000 Hz. Seat belt load cells measured the belt tension at 4 locations. PMHS donation and handling were performed with the approval of the relevant regional ethics review board. Activation of the shoulder PT reduced substantially the peak forward excursion of the head but did not influence the lateral displacement of the head center of gravity (CG). In all 3 subjects, the lateral excursion of the head CG (291.1, 290, 292.1 mm) was greater than the forward displacement (271.4, 216.7, 171.5 mm). The hip joint excursion of the PMHS that was not exposed to the shoulder PT seat belt was twice the magnitude observed for the other 2 subjects. The 3 PMHS sustained clavicle fractures on the shoulder loaded by the seat belt and 2 of them were diagnosed atlantoaxial subluxation in the radiologist examination. Avulsion fractures of the right lamina of T1, T2, T3, and T4 were found when the PT was not used. The 3 PMHS received multiple fractures spread over both aspects of the rib cage and involving the posterior aspect of it. In this study of nearside oblique impact loading, the PMHS exhibited kinematics characterized by reduced torso pitching and increased lateral head excursion as compared to previous frontal impact results. These kinematics resulted in potential cervical and thoracic spinal injuries and in complete, displaced fractures of the lateral and posterior aspects of the rib cage. Though this is a limited number of subjects, it shows the necessity of further understanding of the kinematics of occupants exposed to this loading mode.

  19. Authenticity and Relationship Satisfaction: Two Distinct Ways of Directing Power to Self-Esteem.

    PubMed

    Wang, Yi Nan

    2015-01-01

    Possessing power contributes to high self-esteem, but how power enhances self-esteem is still unknown. As power is associated with both self-oriented goals and social-responsibility goals, we proposed that power predicts self-esteem through two positive personal and interpersonal results: authenticity and relationship satisfaction. Three studies were carried out with a total of 505 Chinese participants, including college students and adults, who completed surveys that assessed personal power, self-esteem, authenticity, relationship satisfaction, communal orientation, and social desirability. Hierarchical multiple regression analyses demonstrated that power, authenticity, and relationship satisfaction each uniquely contributed to self-esteem. More importantly, multiple mediation analysis showed that authenticity and relationship satisfaction both mediated the effects of power on self-esteem, even when controlling for participants' communal orientation and social desirability. Our findings demonstrate that authenticity and relationship satisfaction represent two key mechanisms by which power is associated with self-esteem.

  20. Authenticity and Relationship Satisfaction: Two Distinct Ways of Directing Power to Self-Esteem

    PubMed Central

    Wang, Yi Nan

    2015-01-01

    Possessing power contributes to high self-esteem, but how power enhances self-esteem is still unknown. As power is associated with both self-oriented goals and social-responsibility goals, we proposed that power predicts self-esteem through two positive personal and interpersonal results: authenticity and relationship satisfaction. Three studies were carried out with a total of 505 Chinese participants, including college students and adults, who completed surveys that assessed personal power, self-esteem, authenticity, relationship satisfaction, communal orientation, and social desirability. Hierarchical multiple regression analyses demonstrated that power, authenticity, and relationship satisfaction each uniquely contributed to self-esteem. More importantly, multiple mediation analysis showed that authenticity and relationship satisfaction both mediated the effects of power on self-esteem, even when controlling for participants’ communal orientation and social desirability. Our findings demonstrate that authenticity and relationship satisfaction represent two key mechanisms by which power is associated with self-esteem. PMID:26720814

  1. Real-Time Digital Simulation of Inertial Response with Hardware-in-the-Loop Implementation on the CART3 Wind Turbine at the National Wind Technology Center

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

    Gao, Wenzhong; Wang, Xiao; Muljadi, Eduard

    With increasing penetrations of wind power on electric grids, the stability and reliability of interconnected power systems may be impacted. In some countries that have developed renewable energy sources and systems, grid codes have been revised to require wind power plants (WPPs) to provide ancillary services to support the power system frequency in case of severe grid events. To do this, wind turbine generators (WTGs) should be deloaded to reserve a certain amount of active power for primary frequency response; however, deloading curtails annual energy production, and the market for this type of service needs to be further developed. Inmore » this report, we focus on the temporary frequency support provided by WTGs through inertial response. WTGs have potential to provide inertial response, but appropriate control methods should be implemented. With the implemented inertial control methods, wind turbines are capable of increasing their active power output by releasing some of their stored kinetic energy when a frequency excursion occurs. Active power can be temporarily boosted above the maximum power points, after which the rotor speed decelerates, and subsequently an active power output reduction restores the kinetic energy. In this report, we develop two types of models for wind power systems: the first is common, based on the wind power aerodynamic equation, and the power coefficient can be regressed using nonlinear functions; the second is much more complicated, wherein the wind turbine system is modeled using the Fatigue, Aerodynamics, Structures, and Turbulence Modeling (FAST) tool with several degrees of freedoms. A nine-bus test power system is built in Simulink and the Real-Time Digital Simulator, respectively, which are used to evaluate the frequency support performance of the WPPs. We implement two distinct types of inertial control methods in the modeled wind turbines: frequency-based inertial control (FBIC) and stepwise inertial control (SIC). We compare the performances of the two methods in terms of their frequency nadirs, rates of change of frequency, and recovery times. We conclude the results under various wind speeds and penetration cases, which provide insight into designing the inertial response of WTGs. Further, we discuss the impact of the parameters on the performance of the inertial control methods. We evaluate both the scaling factors for the FBIC method and the slope values for the TLIC methods. The simulation work shows the characteristics of different inertial responses compared to conventional synchronous generators. Based on the simulation results, we modify, improve, and test the inertial control methods under a more realistic wind turbine model based on FAST. We then validate the inertial responses under highly turbulent wind conditions generated by TurbSim, and we examine their influences on the turbine mechanical components. The extensive simulation proves the effectiveness of the proposed inertial control methods as well as the nine-bus test power system. We then reconsider the parameters. We rebuild the same test power system using Real time Simulator Computer Aided Design (RSCAD), and we implement the inertial control methods in the real Controls Advanced Research Turbine (CART3), which is prepared for the hardware-in-the-loop field-test simulation. After the setups for the hardware and software hybrid simulation platform are complete, the inertial response is further tested on a real wind turbine for the first time, in which CART3 release the controlled inertial response against the emulated frequency excursion, provided by the real-time simulated power system test bed in RTDS.« less

  2. Feasibility study of self-powered magnetorheological damper systems

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Liao, Wei-Hsin

    2012-04-01

    This paper is aimed to provide a feasibility study of self-powered magnetorheological (MR) damper systems, which could convert vibration and shock energy into electrical energy to power itself under control. The self-powered feature could bring merits such as higher reliability, energy saving, and less maintenance for the MR damper systems. A self-powered MR damper system is proposed and modeled. The criterion whether the MR damper system is self-powered or not is proposed. A prototype of MR damper with power generation is designed, fabricated, and tested. The modeling of this damper is experimentally validated. Then the damper is applied to a 2 DOF suspension system under on-off skyhook controller, to obtain the self-powered working range and vibration control performance. Effects of key factors on the self-powered MR damper systems are studied. Design considerations are given in order to increase the self-powered working range.

  3. Tokamak plasma current disruption infrared control system

    DOEpatents

    Kugel, Henry W.; Ulrickson, Michael

    1987-01-01

    In a magnetic plasma confinment device having an inner toroidal limiter mounted on an inner wall of a plasma containment vessel, an arrangement is provided for monitoring vertical temperature profiles of the limiter. The temperature profiles are taken at brief time intervals, in a time scan fashion. The time scans of the vertical temperature profile are continuously monitored to detect the presence of a peaked temperature excursion, which, according to the present invention, is a precursor of a subsequent major plasma disruption. A fast scan of the temperature profile is made so as to provide a time interval in real time prior to the major plasma disruption, such that corrective action can be taken to reduce the harmful effects of the plasma disruption.

  4. High field superconducting magnets

    NASA Technical Reports Server (NTRS)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  5. Self-sustaining, solar-driven bioelectricity generation in micro-sized microbial fuel cell using co-culture of heterotrophic and photosynthetic bacteria

    NASA Astrophysics Data System (ADS)

    Liu, Lin; Choi, Seokheun

    2017-04-01

    Among many energy harvesting techniques with great potential, microbial fuel cell (MFC) technology is arguably the most underdeveloped. Even so, excitement is building, as microorganisms can harvest electrical power from any biodegradable organic source (e.g. wastewater) that is readily available in resource-limited settings. Nevertheless, the requirement for endless introduction of organic matter imposes a limiting factor to this technology, demanding an active feeding system and additional power. Here, we demonstrated self-sustaining bioelectricity generation from a microliter-scale microbial fuel cell (MFC) by using the syntrophic interaction between heterotrophic exoelectrogenic bacteria and phototrophs. The MFC continuously generated light-responsive electricity from the heterotrophic bacterial metabolic respiration with the organic substrates produced by photosynthetic bacteria. Without additional organic fuel, the mixed culture in a 90-μL-chamber MFC generated self-sustained current for more than 13 days, while the heterotrophic culture produced current that decreased dramatically within a few hours. The current from the mixed culture was about 70 times greater than that of the device with only photosynthetic bacteria. The miniaturization provided a short start-up time, a well-controlled environment, and small internal resistance. Those advantages will become the general design platform for micropower generation.

  6. Ab-initio quantum transport simulation of self-heating in single-layer 2-D materials

    NASA Astrophysics Data System (ADS)

    Stieger, Christian; Szabo, Aron; Bunjaku, Teutë; Luisier, Mathieu

    2017-07-01

    Through advanced quantum mechanical simulations combining electron transport and phonon transport from first-principles, self-heating effects are investigated in n-type transistors with single-layer MoS2, WS2, and black phosphorus as channel materials. The selected 2-D crystals all exhibit different phonon-limited mobility values, as well as electron and phonon properties, which have a direct influence on the increase in their lattice temperature and on the power dissipated inside their channel as a function of the applied gate voltage and electrical current magnitude. This computational study reveals (i) that self-heating plays a much more important role in 2-D materials than in Si nanowires, (ii) that it could severely limit the performance of 2-D devices at high current densities, and (iii) that black phosphorus appears less sensitive to this phenomenon than transition metal dichalcogenides.

  7. Balance Training Versus Balance Training With STARS in Patients With Chronic Ankle Instability: A Randomized Controlled Trial.

    PubMed

    Burcal, Christopher J; Trier, Alejandra Y; Wikstrom, Erik A

    2017-09-01

    Both balance training and selected interventions meant to target sensory structures (STARS) have been shown to be effective at restoring deficits associated with chronic ankle instability (CAI). Clinicians often use multiple treatment modalities in patients with CAI. However, evidence for combined intervention effectiveness in CAI patients remains limited. To determine if augmenting a balance-training protocol with STARS (BTS) results in greater improvements than balance training (BT) alone in those with CAI. Randomized-controlled trial. Research laboratory. 24 CAI participants (age 21.3 ± 2.0 y; height 169.8 ± 12.9 cm; mass 72.5 ± 22.2 kg) were randomized into 2 groups: BT and BTS. Participants completed a 4-week progression-based balance-training protocol consisting of 3 20-min sessions per week. The experimental group also received a 5-min set of STARS treatments consisting of calf stretching, plantar massage, ankle joint mobilizations, and ankle joint traction before each balance-training session. Outcomes included self-assessed disability, Star Excursion Balance Test reach distance, and time-to-boundary calculated from static balance trials. All outcomes were assessed before, and 24-hours and 1-week after protocol completion. Self-assessed disability was also captured 1-month after the intervention. No significant group differences were identified (P > .10). Both groups demonstrated improvements in all outcome categories after the interventions (P < .10), many of which were retained at 1-week posttest (P < .10). Although 90% CIs include zero, effect sizes favor BTS. Similarly, only the BTS group exceeded the minimal detectable change for time-to-boundary outcomes. While statistically no more effective, exceeding minimal detectable change scores and favorable effect sizes suggest that a 4-week progressive BTS program may be more effective at improving self-assessed disability and postural control in CAI patients than balance training in isolation.

  8. Predictors of chronic ankle instability: Analysis of peroneal reaction time, dynamic balance and isokinetic strength.

    PubMed

    Sierra-Guzmán, Rafael; Jiménez, Fernando; Abián-Vicén, Javier

    2018-05-01

    Previous studies have reported the factors contributing to chronic ankle instability, which could lead to more effective treatments. However, factors such as the reflex response and ankle muscle strength have not been taken into account in previous investigations. Fifty recreational athletes with chronic ankle instability and 55 healthy controls were recruited. Peroneal reaction time in response to sudden inversion, isokinetic evertor muscle strength and dynamic balance with the Star Excursion Balance Test and the Biodex Stability System were measured. The relationship between the Cumberland Ankle Instability Tool score and performance on each test was assessed and a backward multiple linear regression analysis was conducted. Participants with chronic ankle instability showed prolonged peroneal reaction time, poor performance in the Biodex Stability System and decreased reach distance in the Star Excursion Balance Test. No significant differences were found in eversion and inversion peak torque. Moderate correlations were found between the Cumberland Ankle Instability Tool score and the peroneal reaction time and performance on the Star Excursion Balance Test. Peroneus brevis reaction time and the posteromedial and lateral directions of the Star Excursion Balance Test accounted for 36% of the variance in the Cumberland Ankle Instability Tool. Dynamic balance deficits and delayed peroneal reaction time are present in participants with chronic ankle instability. Peroneus brevis reaction time and the posteromedial and lateral directions of the Star Excursion Balance Test were the main contributing factors to the Cumberland Ankle Instability Tool score. No clear strength impairments were reported in unstable ankles. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Knee joint contact mechanics during downhill gait and its relationship with varus/valgus motion and muscle strength in patients with knee osteoarthritis.

    PubMed

    Farrokhi, Shawn; Voycheck, Carrie A; Gustafson, Jonathan A; Fitzgerald, G Kelley; Tashman, Scott

    2016-01-01

    The objective of this exploratory study was to evaluate tibiofemoral joint contact point excursions and velocities during downhill gait and assess the relationship between tibiofemoral joint contact mechanics with frontal-plane knee joint motion and lower extremity muscle weakness in patients with knee osteoarthritis (OA). Dynamic stereo X-ray was used to quantify tibiofemoral joint contact mechanics and frontal-plane motion during the loading response phase of downhill gait in 11 patients with knee OA and 11 control volunteers. Quantitative testing of the quadriceps and the hip abductor muscles was also performed. Patients with knee OA demonstrated larger medial/lateral joint contact point excursions (p < 0.02) and greater heel-strike joint contact point velocities (p < 0.05) for the medial and lateral compartments compared to the control group. The peak medial/lateral joint contact point velocity of the medial compartment was also greater for patients with knee OA compared to their control counterparts (p = 0.02). Additionally, patients with knee OA demonstrated significantly increased frontal-plane varus motion excursions (p < 0.01) and greater quadriceps and hip abductor muscle weakness (p = 0.03). In general, increased joint contact point excursions and velocities in patients with knee OA were linearly associated with greater frontal-plane varus motion excursions (p < 0.04) but not with quadriceps or hip abductor strength. Altered contact mechanics in patients with knee OA may be related to compromised frontal-plane joint stability but not with deficits in muscle strength.

  10. Kinematic predictors of star excursion balance test performance in individuals with chronic ankle instability.

    PubMed

    Hoch, Matthew C; Gaven, Stacey L; Weinhandl, Joshua T

    2016-06-01

    The Star Excursion Balance Test has identified dynamic postural control deficits in individuals with chronic ankle instability. While kinematic predictors of Star Excursion Balance Test performance have been evaluated in healthy individuals, this has not been thoroughly examined in individuals with chronic ankle instability. Fifteen individuals with chronic ankle instability completed the anterior reach direction of the Star Excursion Balance Test and weight-bearing dorsiflexion assessments. Maximum reach distances on the Star Excursion Balance Test were measured in cm and normalized to leg length. Three-dimensional trunk, hip, knee, and ankle motion of the stance limb were recorded during each anterior reach trial using a motion capture system. Sagittal, frontal, and transverse plane displacement observed from trial initiation to the point of maximum reach was calculated for each joint or segment and averaged for analysis. Pearson product-moment correlations were performed to examine the relationships between kinematic variables, maximal reach, and weight-bearing dorsiflexion. A backward multiple linear regression model was developed with maximal reach as the criterion variable and kinematic variables as predictors. Frontal plane displacement of the trunk, hip, and ankle and sagittal plane knee displacement were entered into the analysis. The final model (p=0.004) included all three frontal plane variables and explained 81% of the variance in maximal reach. Maximal reach distance and several kinematic variables were significantly related to weight-bearing dorsiflexion. Individuals with chronic ankle instability who demonstrated greater lateral trunk displacement toward the stance limb, hip adduction, and ankle eversion achieved greater maximal reach. Copyright © 2016. Published by Elsevier Ltd.

  11. Design of insulin analogues for meal-related therapy.

    PubMed

    Brange, J

    1993-01-01

    The human insulin in replacement therapy has a hexameric structure. Hexamerization of the insulin molecule facilitates biosynthesis and beta-cell storage of insulin, but is unnecessary for biologic activity and appears to contribute to delayed absorption of exogenous insulin from the subcutis. Insulin analogues with reduced self-association that are produced through recombinant DNA techniques have been shown to have in vivo activity comparable to that of human insulin and absorption kinetics characterized by higher and more constant rates of disappearance from the subcutaneous injection site. In preliminary studies in patients receiving insulin therapy, monomeric insulin analogues have been found to provide glycemic control in the postprandial period that is at least equivalent to that of human insulin. Findings in these studies suggest that the use of such analogues may provide meal-related insulin effects closer to those observed in the physiologic state by limiting excessive postprandial glucose excursions and decreasing the risk of late hypoglycemia. Banting and Best revolutionized diabetes therapy 70 years ago with the extraction of insulin from animal pancreas glands (J Lab Clin Med 7:464-472, 1922). Since that time, many refinements of the therapeutic properties of pharmaceutical preparations of the hormone have been introduced. Until recently, however, such advances have been limited to improvements in insulin purity, insulin species, and adjustment of the composition of the vehicle with respect to auxiliary substances and other additives. With the advent of recombinant DNA techniques, it has become possible to optimize the insulin molecule itself for purposes of replacement therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. A Self-Referencing Intensity-Based Fiber Optic Sensor with Multipoint Sensing Characteristics

    PubMed Central

    Choi, Sang-Jin; Kim, Young-Chon; Song, Minho; Pan, Jae-Kyung

    2014-01-01

    A self-referencing, intensity-based fiber optic sensor (FOS) is proposed and demonstrated. The theoretical analysis for the proposed design is given, and the validity of the theoretical analysis is confirmed via experiments. We define the measurement parameter, X, and the calibration factor, β, to find the transfer function, Hm,n, of the intensity-based FOS head. The self-referencing and multipoint sensing characteristics of the proposed system are validated by showing the measured Hm,n2 and relative error versus the optical power attenuation of the sensor head for four cases: optical source fluctuation, various remote sensing point distances, fiber Bragg gratings (FBGs) with different characteristics, and multiple sensor heads with cascade and/or parallel forms. The power-budget analysis and limitations of the measurement rates are discussed, and the measurement results of fiber-reinforced plastic (FRP) coupon strain using the proposed FOS are given as an actual measurement. The proposed FOS has several benefits, including a self-referencing characteristic, the flexibility to determine FBGs, and a simple structure in terms of the number of devices and measuring procedure. PMID:25046010

  13. Metabolic responses to prolonged consumption of glucose- and fructose-sweetened beverages are not associated with postprandial or 24-hour glucose and insulin excursions

    USDA-ARS?s Scientific Manuscript database

    It has been proposed that the adverse metabolic effects of chronic consumption of sugar-sweetened beverages which contain both glucose and fructose are a consequence of increased circulating glucose and insulin excursions, i.e dietary glycemic index (GI). Objective: We determined if the greater adv...

  14. A Teaching-Learning Sequence of Colour Informed by History and Philosophy of Science

    ERIC Educational Resources Information Center

    Maurício, Paulo; Valente, Bianor; Chagas, Isabel

    2017-01-01

    In this work, we present a teaching-learning sequence on colour intended to a pre-service elementary teacher programme informed by History and Philosophy of Science. Working in a socio-constructivist framework, we made an excursion on the history of colour. Our excursion through history of colour, as well as the reported misconception on colour…

  15. A Normative-Speaker Validation Study of Two Indices Developed to Quantify Tongue Dorsum Activity from Midsagittal Tongue Shapes

    ERIC Educational Resources Information Center

    Zharkova, Natalia

    2013-01-01

    This study reported adult scores on two measures of tongue shape, based on midsagittal tongue shape data from ultrasound imaging. One of the measures quantified the extent of tongue dorsum excursion, and the other measure represented the place of maximal excursion. Data from six adult speakers of Scottish Standard English without speech disorders…

  16. Tuning the Field Trip: Audio-Guided Tours as a Replacement for 1-Day Excursions in Human Geography

    ERIC Educational Resources Information Center

    Wissmann, Torsten

    2013-01-01

    Educators are experiencing difficulties with 1-day field trips in human geography. Instead of teaching students how to apply theory in the field and learn to "sense" geography in everyday life, many excursions have degraded into tourist-like events where lecturers try to motivate rather passive students against a noisy urban backdrop.…

  17. Conference Committees: Conference Committees

    NASA Astrophysics Data System (ADS)

    2009-09-01

    International Programm Committee (IPC) Harald Ade NCSU Sadao Aoki University Tsukuba David Attwood Lawrence Berkeley National Laboratory/CXRO Christian David Paul Scherrer Institut Peter Fischer Lawrence Berkeley National Laboratory Adam Hitchcock McMaster University Chris Jacobsen SUNY, Stony Brook Denis Joyeux Lab Charles Fabry de l'Institut d'Optique Yasushi Kagoshima University of Hyogo Hiroshi Kihara Kansai Medical University Janos Kirz SUNY Stony Brook Maya Kiskinova ELETTRA Ian McNulty Argonne National Lab/APS Alan Michette Kings College London Graeme Morrison Kings College London Keith Nugent University of Melbourne Zhu Peiping BSRF Institute of High Energy Physics Francois Polack Soleil Christoph Quitmann Paul Scherrer Institut Günther Schmahl University Göttingen Gerd Schneider Bessy Hyun-Joon Shin Pohang Accelerator Lab Jean Susini ESRF Mau-Tsu Tang NSRRC Tony Warwick Lawrence Berkeley Lab/ALS Local Organizing Committee Christoph Quitmann Chair, Scientific Program Charlotte Heer Secretary Christian David Scientific Program Frithjof Nolting Scientific Program Franz Pfeiffer Scientific Program Marco Stampanoni Scientific Program Robert Rudolph Sponsoring, Financials Alfred Waser Industry Exhibition Robert Keller Public Relation Markus Knecht Computing and WWW Annick Cavedon Proceedings and Excursions and Accompanying Persons Program Margrit Eichler Excursions and Accompanying Persons Program Kathy Eikenberry Excursions and Accompanying Persons Program Marlies Locher Excursions and Accompanying Persons Program

  18. Age of the Mono Lake excursion and associated tephra

    USGS Publications Warehouse

    Benson, L.; Liddicoat, J.; Smoot, J.; Sarna-Wojcicki, A.; Negrini, R.; Lund, S.

    2003-01-01

    The Mono Lake excursion (MLE) is an important time marker that has been found in lake and marine sediments across much of the Northern Hemisphere. Dating of this event at its type locality, the Mono Basin of California, has yielded controversial results with the most recent effort concluding that the MLE may actually be the Laschamp excursion (Earth Planet. Sci. Lett. 197 (2002) 151). We show that a volcanic tephra (Ash #15) that occurs near the midpoint of the MLE has a date (not corrected for reservoir effect) of 28,620 ?? 300 14C yr BP (??? 32,400 GISP2 yr BP) in the Pyramid Lake Basin of Nevada. Given the location of Ash #15 and the duration of the MLE in the Mono Basin, the event occurred between 31,500 and 33,300 GISP2 yr BP, an age range consistent with the position and age of the uppermost of two paleointensity minima in the NAPIS-75 stack that has been associated with the MLE (Philos. Trans. R. Soc. London Ser. A 358 (2000) 1009). The lower paleointensity minimum in the NAPIS-75 stack is considered to be the Laschamp excursion (Philos. Trans. R. Soc. London Ser. A 358 (2000) 1009).

  19. SpalLoop

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

    Sabau, Adrian; Wright, Ian

    Boiler tubes in steam power plants experience tube blockages due to exfoliation of oxide grown on the inner side of the tubes. In extreme cases, significant tube blockages can lead to forced power plant outages. It is thus desired to predict through modeling the amount of tube blockage in order to inform power plant operators of possible forced outages. SpalLoop solves for the stress-strain equations in an axisymmetric geometry, tracking the stress/strain evolution during boiler operation including outages for the entire boiler tube length. At each operational outage, i.e., temperature excursions down to room temperature, the amount of exfoliated areamore » for the entire tube loop is estimated the amount of tube blockage is predicted based assumed blockage geometry and site. The SpaLLoop code contains modules developed for oxide growth, stress analysis, tube loop geometry, blockage area by taking into account the following phenomena and features, (a) Plant operation schedule with periodic alternate full-load and partial-load regimes and shut-downs, i.e., temperature excursions from high-load to room temperature, (b) axisymmetric formulation for cylindrical tubes, (c) oxide growth in a temperature gradient with multiple oxide layers, (d) geometry of a boiler tube with a single tube loop or two tube loops, (e) temperature variation along the tube length based on hot gas temperature distribution outside the tube and inlet steam temperature, (f) non-uniform oxide growth along the tube length according to the local steam tube temperature, (g) exfoliated area module: at each operational outage considered, the amount of exfoliated area and exfoliated volume along the tube is estimated, (h) blockage module: at each operational outage considered, the exfoliated volume/mass for each tube loop is estimated from which the amount of tube blockage is predicted based on given blockage geometry (length, location, and geometry). The computer program is written in FORTRAN90. Its modular structure was sought for allowing the best flexibility in updating the program by implementing new constitutive equations due to availability of new material property data and/or new physical phenomena.« less

  20. Assessing electronic cigarette effects and regulatory impact: Challenges with user self-reported device power.

    PubMed

    Rudy, Alyssa K; Leventhal, Adam M; Goldenson, Nicholas I; Eissenberg, Thomas

    2017-10-01

    Electronic cigarettes (ECIGs) aerosolize liquids for user inhalation that usually contain nicotine. ECIG nicotine emission is determined, in part, by user behavior, liquid nicotine concentration, and electrical power. Whether users are able to report accurately nicotine concentration and device electrical power has not been evaluated. This study's purpose was to examine if ECIG users could provide data relevant to understanding ECIG nicotine emission, particularly liquid nicotine concentration (mg/ml) as well as battery voltage (V) and heater resistance (ohms, Ω) - needed to calculate power (watts, W). Adult ECIG users (N=165) were recruited from Los Angeles, CA for research studies examining the effects of ECIG use. We asked all participants who visited the laboratory to report liquid nicotine concentration, V, and Ω. Liquid nicotine concentration was reported by 89.7% (mean=9.5mg/ml, SD=7.3), and responses were consistent with the distribution of liquids available in commonly marketed products. The majority could not report voltage (51.5%) or resistance (63.6%). Of the 40 participants (24.8%) who reported voltage and resistance, there was a substantial power range (2.2-32,670W) the upper limit of which exceeds that of the highest ECIG reported by any user to our knowledge (i.e., 2512W). If 2512W is taken as the upper limit, only 30 (18.2%) reported valid results (mean 237.3W, SD=370.6; range=2.2-1705.3W). Laboratory, survey, and other researchers interested in understanding ECIG effects to inform users and policymakers may need to use methods other than user self-report to obtain information regarding device power. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Testing Postural Stability: Are the Star Excursion Balance Test and Biodex Balance System Limits of Stability Tests Consistent?

    PubMed

    Glave, A Page; Didier, Jennifer J; Weatherwax, Jacqueline; Browning, Sarah J; Fiaud, Vanessa

    2016-01-01

    There are a variety of options to test postural stability; however many physical tests lack validity information. Two tests of postural stability - the Star Excursion Balance Test (SEBT) and Biodex Balance System Limits of Stability Test (LOS) - were examined to determine if similar components of balance were measured. Healthy adults (n=31) completed the LOS (levels 6 and 12) and SEBT (both legs). SEBT directions were offset by 180° to approximate LOS direction. Correlations and partial correlations controlling for height were analyzed. Correlations were significant for SEBT 45° and LOS back-left (6: r=-0.41; 12: r=-0.42; p<0.05), SEBT 90° and LOS 6 left (r=-0.51, p<0.05), SEBT 135(o) and LOS 6 front-left (r=-0.53, p<0.05), SEBT overall and LOS 6 overall (r=-0.43, p<0.05). Partial correlations were significant for SEBT 90° and LOS 6 left (rSEBT,LOS·H=-0.45, p<0.05) and SEBT 135° and LOS 6 front-left (rSEBT,LOS·H=-0.51, p<0.05), and SEBT overall and LOS 6 overall (rSEBT,LOS·H=-0.37, p<0.05). These findings indicate the tests seem to assess different components of balance. Research is needed to determine and define what specific components of balance are being assessed. Care must be taken when choosing balance tests to best match the test to the purpose of testing (fall risk, athletic performance, etc.). Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Performance of conducting polymer electrodes for stimulating neuroprosthetics

    NASA Astrophysics Data System (ADS)

    Green, R. A.; Matteucci, P. B.; Hassarati, R. T.; Giraud, B.; Dodds, C. W. D.; Chen, S.; Byrnes-Preston, P. J.; Suaning, G. J.; Poole-Warren, L. A.; Lovell, N. H.

    2013-02-01

    Objective. Recent interest in the use of conducting polymers (CPs) for neural stimulation electrodes has been growing; however, concerns remain regarding the stability of coatings under stimulation conditions. These studies examine the factors of the CP and implant environment that affect coating stability. The CP poly(ethylene dioxythiophene) (PEDOT) is examined in comparison to platinum (Pt), to demonstrate the potential performance of these coatings in neuroprosthetic applications. Approach. PEDOT is coated on Pt microelectrode arrays and assessed in vitro for charge injection limit and long-term stability under stimulation in biologically relevant electrolytes. Physical and electrical stability of coatings following ethylene oxide (ETO) sterilization is established and efficacy of PEDOT as a visual prosthesis bioelectrode is assessed in the feline model. Main results. It was demonstrated that PEDOT reduced the potential excursion at a Pt electrode interface by 72% in biologically relevant solutions. The charge injection limit of PEDOT for material stability was found to be on average 30× larger than Pt when tested in physiological saline and 20× larger than Pt when tested in protein supplemented media. Additionally stability of the coating was confirmed electrically and morphologically following ETO processing. It was demonstrated that PEDOT-coated electrodes had lower potential excursions in vivo and electrically evoked potentials (EEPs) could be detected within the visual cortex. Significance. These studies demonstrate that PEDOT can be produced as a stable electrode coating which can be sterilized and perform effectively and safely in neuroprosthetic applications. Furthermore these findings address the necessity for characterizing in vitro properties of electrodes in biologically relevant milieu which mimic the in vivo environment more closely.

  3. A Quaternary Geomagnetic Instability Time Scale

    NASA Astrophysics Data System (ADS)

    Singer, B. S.

    2013-12-01

    Reversals and excursions of Earth's geomagnetic field create marker horizons that are readily detected in sedimentary and volcanic rocks worldwide. An accurate and precise chronology of these geomagnetic field instabilities is fundamental to understanding several aspects of Quaternary climate, dynamo processes, and surface processes. For example, stratigraphic correlation between marine sediment and polar ice records of climate change across the cryospheres benefits from a highly resolved record of reversals and excursions. The temporal patterns of dynamo behavior may reflect physical interactions between the molten outer core and the solid inner core or lowermost mantle. These interactions may control reversal frequency and shape the weak magnetic fields that arise during successive dynamo instabilities. Moreover, weakening of the axial dipole during reversals and excursions enhances the production of cosmogenic isotopes that are used in sediment and ice core stratigraphy and surface exposure dating. The Geomagnetic Instability Time Scale (GITS) is based on the direct dating of transitional polarity states recorded by lava flows using the 40Ar/39Ar method, in parallel with astrochronologic age models of marine sediments in which O isotope and magnetic records have been obtained. A review of data from Quaternary lava flows and sediments yields a GITS comprising 10 polarity reversals and 27 excursions during the past 2.6 million years. Nine of the ten reversals bounding chrons and subchrons are associated with 40Ar/39Ar ages of transitionally-magnetized lava flows. The tenth, the Guass-Matuyama chron boundary, is tightly bracketed by 40Ar/39Ar dated ash deposits. Of the 27 well-documented excursions, 14 occurred during the Matuyama chron and 13 during the Brunhes chron; 19 have been dated directly using the 40Ar/39Ar method on transitionally-magnetized volcanic rocks and form the backbone of the GITS. Excursions are clearly not the rare phenomena once thought. Rather, during the Quaternary period, they occur nearly three times as often as full polarity reversals. I will address analytical issues, including the size and consistency of system blanks, that have led to the recognition of minor (1%) discrepencies between the 40Ar/39Ar age for a particular reversal or excursion and the best astrochronologic estimates from ODP sediment cores. For example, re-analysis of lava flows from Haleakala volcano, Maui that record in detail the Matuyama-Brunhes polarity reversal have been undertaken with blanks an order of magntitude smaller and more stable than was common a decade ago. Using the modern astrochronologic calibration of 28.201 Ma for the age of the Fish Canyon sanidine standard, results thus far yield an 40Ar/39Ar age of 772 × 11 ka for the reversal that is identical to the most precise and accurate astrochronologic age of 773 × 2 ka for this reversal from ODP cores. Similarly, new dating of sanidine in the Cerro Santa Rosa I rhyolite dome, New Mexico reveals an age of 932 × 5 ka for the excursion it records, in perfect agreement with astrochronologically dated ODP core records. Work underway aims at refining the 40Ar/39Ar ages that underpin the entire GITS by further eliminating the bias between the radioisotopic and astrochronologically determined ages for several reversals and excursions.

  4. Use of a Connected Glucose Meter and Certified Diabetes Educator Coaching to Decrease the Likelihood of Abnormal Blood Glucose Excursions: The Livongo for Diabetes Program.

    PubMed

    Downing, Janelle; Bollyky, Jenna; Schneider, Jennifer

    2017-07-11

    The Livongo for Diabetes Program offers members (1) a cellular technology-enabled, two-way messaging device that measures blood glucose (BG), centrally stores the glucose data, and delivers messages back to the individual in real time; (2) unlimited BG test strips; and (3) access to a diabetes coaching team for questions, goal setting, and automated support for abnormal glucose excursions. The program is sponsored by at-risk self-insured employers, health plans and provider organizations where it is free to members with diabetes or it is available directly to the person with diabetes where they cover the cost. The objective of our study was to evaluate BG data from 4544 individuals with diabetes who were enrolled in the Livongo program from October 2014 through December 2015. Members used the Livongo glucose meter to measure their BG levels an average of 1.8 times per day. We estimated the probability of having a day with a BG reading outside of the normal range (70-180 mg/dL, or 3.9-10.0 mmol/L) in months 2 to 12 compared with month 1 of the program, using individual fixed effects to control for individual characteristics. Livongo members experienced an average 18.4% decrease in the likelihood of having a day with hypoglycemia (BG <70 mg/dL) and an average 16.4% decrease in hyperglycemia (BG >180 mg/dL) in months 2-12 compared with month 1 as the baseline. The biggest impact was seen on hyperglycemia for nonusers of insulin. We do not know all of the contributing factors such as medication or other treatment changes during the study period. These findings suggest that access to a connected glucose meter and certified diabetes educator coaching is associated with a decrease in the likelihood of abnormal glucose excursions, which can lead to diabetes-related health care savings. ©Janelle Downing, Jenna Bollyky, Jennifer Schneider. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 11.07.2017.

  5. Differences in participation based on self-esteem in power and manual wheelchair users on a university campus: a pilot study.

    PubMed

    Rice, Ian M; Wong, Alex W K; Salentine, Benjamin A; Rice, Laura A

    2015-03-01

    To examine the relationship of self-esteem and wheelchair type with participation of young adult manual and power wheelchair users with diverse physical disabilities. Cross-sectional survey study. Large University Campus. A convenience sample of college students (N = 39) with self-reported physical disabilities who are full time wheelchair users (>40 per week) and are two or more years post illness or injury. Not applicable. The Rosenberg Self-Esteem Scale was used to measure self-esteem, and the Craig Handicap Assessment and Reporting Technique was used to measure participation. Self-esteem correlated highly with cognitive independence (CI) (r = 0.58), mobility (r = 0.67) and social integration (SI) (r = 0.52). Use of manual wheelchair was significantly related to higher levels of CI and mobility while longer use of any wheelchair (power or manual) was significantly associated with higher levels of mobility and SI. In addition higher self-esteem independently predicted a significant proportion of the variance in CI, mobility and SI, while type of wheelchair predicted a significant proportion of the variance in CI (p < 0.005). High self-esteem was found to be the strongest predictor of participation in a population of young adults with mobility limitations. Better understanding of the factors influencing participation may help to facilitate new interventions to minimize the disparities between persons with disabilities and their able bodied peers. Implication for Rehabilitation A total of 46.8% of wheelchair users report the desire for increased community participant but face significant barriers. The type of wheelchair has been identified as having a large impact on participation. This study found self-esteem to be the strongest predictor of participation, which is notable because self-esteem is a characteristic that is potentially modifiable with treatment.

  6. Clinician-Friendly Physical Performance Tests for the Hip, Ankle, and Foot.

    PubMed

    Vogler, Joseph H; Csiernik, Alexander J; Yorgey, Marissa K; Harrison, Jerrod J; Games, Kenneth E

    2017-09-01

    Reference:  Hegedus EJ, McDonough SM, Bleakley C, Baxter D, Cook CE. Clinician-friendly lower extremity physical performance tests in athletes: a systematic review of measurement properties and correlation with injury. Part 2: the tests for the hip, thigh, foot, and ankle including the Star Excursion Balance Test. Br J Sports Med. 2015;49(10):649-656.   Do individual physical performance tests (PPTs) for the lower extremity have any relation to injury in athletes 12 years of age and older?   The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to locate articles. Three databases were searched from inception to January 13, 2014: PubMed, CINAHL, and SPORTDiscus. Search phrases were sport, athletics, athletes, and injuries combined with strength, power, endurance, agility, and function. Reference lists of all remaining articles and personal collections of the authors were then reviewed for any missing articles.   Studies were included according to the following criteria: (1) published in English, (2) presented as complete articles (ie, no abstracts or posters), and (3) involved human participants. Studies were excluded on the following criteria: (1) a combination of PPTs was examined, (2) the results were measured using equipment that was expensive or not readily available to the average clinician, (3) the PPTs examined impairment-level data, (4) the PPTs examined tasks not relevant to the lower extremity, or (5) the participants scored 4 or less on the Tegner Activity Scale. The final analysis involved 31 studies.   The name of the PPT and methods were extracted. Each PPT was then critiqued using the Consensus-Based Standards for the Selection of Health Measurement Instruments, a 4-point Likert scale. Data were also summarized using a score of unknown, strong, moderate, limited, or conflicting for the best evidence synthesis.   A total of 14 PPTs were examined; however, names and methods of the PPTs were inconsistent throughout the literature. In descending order, based on frequency of appearance in the literature, the PPTs were (1) 1-legged hop for distance, (2) vertical jump, (3) Star Excursion Balance Test, (4) shuttle run, (5) 6-m timed hop, (6) triple hop, (7) 40-yd sprint, (8) triple crossover hop for distance, (9) 6-m timed crossover hop, (10) T-agility, (11) hexagon hop, (12) medial hop, (13) lateral hop, and (14) multi-stage fitness (beep test). The Star Excursion Balance Test in the anterior, posteromedial, and posterolateral directions was the only test that could help identify injury risk. The 1-legged hop for distance and hexagon hop showed a moderate ability to differentiate between normal and unstable ankles. In dancers, the medial hop in dancers differentiated between painful and normal hips with moderate evidence.   Very little evidence supports the use of PPTs for athletes with lower extremity injuries. A panel of experts needs to standardize the names and methods of widely accepted tests.

  7. New successful ideas to teach Earth Science to students older than 55 by means of trekking

    NASA Astrophysics Data System (ADS)

    Fernández Raga, María; Cerdà, Artemi; Civera, Cristina

    2013-04-01

    During the last 10 years, the Geograns Program within the NAUGRAN initiative of the University of Valencia is using trekking as a way to teach in the field Earth Science. This paper review the contribution of this program and show the results and future challenges. The life expectancy is growing all over the world. This is a clear trend in the Western societies where after two generations there is a large group of inhabitants that have a new life after retirement. The universities must understand that this new group of citizens need services that will allow them to know better the society. This is why the University of Valencia developed in the end of the 90's a program to teach to students older than 55. The program that allows to those students to attend lectures at the University is called NAUGRAN. This is a program for more than one thousand students that cover the needs of a group that is having more and more population over the age of 55, and with a life expectancy that surpass the 81 years in Spain. Teaching History, Arts, Sciences or Literature can be easily due for those 55-old students. However, teaching geosciences is being very difficult, as the students must visit the field and the laboratory. Within the GEOGRANS project, and during the last six years, Physical Geography was taught to students older than 55 in independent lecture rooms and field and laboratory classes. The main strategy was to show them the concepts and the ideas of the Physical Geography in the field. The excursions allow to shown the main features of the landscape (rivers, mountains, rocks…) and the impacts of the humankind on the changes of the nature to the students. The program is now 6 years old and it is being very successful with more than 200 hundreds participants and with excursion every two weeks. This paper will show the importance of teaching to students that arrive to the university after retirement. And that trekking is a successful strategy as the students realise that they can be active and see the environmental changes suffered but the the land and the society. During the last 10 years more than 100 excursion were done by the Geograns Project. They were mainly one-day excursion, but sometimes two days excursions and one week excursions are done. The three types of excursions are showing positive acceptance of the students.

  8. A miniature batteryless health and usage monitoring system based on hybrid energy harvesting

    NASA Astrophysics Data System (ADS)

    Huang, Chenling; Chakrabartty, Shantanu

    2011-04-01

    The cost and size of the state-of-the-art health and usage monitoring systems (HUMS) are determined by capacity of on-board energy storage which limits their large scale deployment. In this paper, we present a miniature low-cost mechanical HUMS integrated circuit (IC) based on the concept of hybrid energy harvesting where continuous monitoring is achieved by self-powering, where as the programming, localization and communication with the sensor is achieved using remote RF powering. The self-powered component of the proposed HUMS is based on our previous result which used a controllable hot electron injection on floatinggate transistor as an ultra-low power signal processor. We show that the HUMS IC can seamlessly switch between different energy harvesting modes based on the availability of ambient RF power and that the configuration, programming and communication functions can be remotely performed without physically accessing the HUMS device. All the measured results presented in this paper have been obtained from prototypes fabricated in a 0.5 micron standard CMOS process and the entire system has been successfully integrated on a 1.5cm x 1.5cm package.

  9. Enhancing the Teaching of Digital Processing of Remote Sensing Image Course through Geospatial Web Processing Services

    NASA Astrophysics Data System (ADS)

    di, L.; Deng, M.

    2010-12-01

    Remote sensing (RS) is an essential method to collect data for Earth science research. Huge amount of remote sensing data, most of them in the image form, have been acquired. Almost all geography departments in the world offer courses in digital processing of remote sensing images. Such courses place emphasis on how to digitally process large amount of multi-source images for solving real world problems. However, due to the diversity and complexity of RS images and the shortcomings of current data and processing infrastructure, obstacles for effectively teaching such courses still remain. The major obstacles include 1) difficulties in finding, accessing, integrating and using massive RS images by students and educators, and 2) inadequate processing functions and computing facilities for students to freely explore the massive data. Recent development in geospatial Web processing service systems, which make massive data, computing powers, and processing capabilities to average Internet users anywhere in the world, promises the removal of the obstacles. The GeoBrain system developed by CSISS is an example of such systems. All functions available in GRASS Open Source GIS have been implemented as Web services in GeoBrain. Petabytes of remote sensing images in NASA data centers, the USGS Landsat data archive, and NOAA CLASS are accessible transparently and processable through GeoBrain. The GeoBrain system is operated on a high performance cluster server with large disk storage and fast Internet connection. All GeoBrain capabilities can be accessed by any Internet-connected Web browser. Dozens of universities have used GeoBrain as an ideal platform to support data-intensive remote sensing education. This presentation gives a specific example of using GeoBrain geoprocessing services to enhance the teaching of GGS 588, Digital Remote Sensing taught at the Department of Geography and Geoinformation Science, George Mason University. The course uses the textbook "Introductory Digital Image Processing, A Remote Sensing Perspective" authored by John Jensen. The textbook is widely adopted in the geography departments around the world for training students on digital processing of remote sensing images. In the traditional teaching setting for the course, the instructor prepares a set of sample remote sensing images to be used for the course. Commercial desktop remote sensing software, such as ERDAS, is used for students to do the lab exercises. The students have to do the excurses in the lab and can only use the simple images. For this specific course at GMU, we developed GeoBrain-based lab excurses for the course. With GeoBrain, students now can explore petabytes of remote sensing images in the NASA, NOAA, and USGS data archives instead of dealing only with sample images. Students have a much more powerful computing facility available for their lab excurses. They can explore the data and do the excurses any time at any place they want as long as they can access the Internet through the Web Browser. The feedbacks from students are all very positive about the learning experience on the digital image processing with the help of GeoBrain web processing services. The teaching/lab materials and GeoBrain services are freely available to anyone at http://www.laits.gmu.edu.

  10. Effect of long-duration spaceflight on postural control during self-generated perturbations

    NASA Technical Reports Server (NTRS)

    Layne, C. S.; Mulavara, A. P.; McDonald, P. V.; Pruett, C. J.; Kozlovskaya, I. B.; Bloomberg, J. J.

    2001-01-01

    This report is the first systematic evaluation of the effects of prolonged weightlessness on the bipedal postural control processes during self-generated perturbations produced by voluntary upper limb movements. Spaceflight impacts humans in a variety of ways, one of which is compromised postflight postural control. We examined the neuromuscular activation characteristics and center of pressure (COP) motion associated with arm movement of eight subjects who experienced long-duration spaceflight (3--6 mo) aboard the Mir space station. Surface electromyography, arm acceleration, and COP motion were collected while astronauts performed rapid unilateral shoulder flexions before and after spaceflight. Subjects generally displayed compromised postural control after flight, as evidenced by modified COP peak-to-peak anterior-posterior and mediolateral excursion, and pathlength relative to preflight values. These changes were associated with disrupted neuromuscular activation characteristics, particularly after the completion of arm acceleration (i.e., when subjects were attempting to maintain upright posture in response to self-generated perturbations). These findings suggest that, although the subjects were able to assemble coordination modes that enabled them to generate rapid arm movements, the subtle control necessary to maintain bipedal equilibrium evident in their preflight performance is compromised after long-duration spaceflight.

  11. Time-Resolved Quantitative Analysis of the Diaphragms During Tidal Breathing in a Standing Position Using Dynamic Chest Radiography with a Flat Panel Detector System ("Dynamic X-Ray Phrenicography"): Initial Experience in 172 Volunteers.

    PubMed

    Yamada, Yoshitake; Ueyama, Masako; Abe, Takehiko; Araki, Tetsuro; Abe, Takayuki; Nishino, Mizuki; Jinzaki, Masahiro; Hatabu, Hiroto; Kudoh, Shoji

    2017-04-01

    Diaphragmatic motion in a standing position during tidal breathing remains unclear. The purpose of this observational study was to evaluate diaphragmatic motion during tidal breathing in a standing position in a health screening center cohort using dynamic chest radiography in association with participants' demographic characteristics. One hundred seventy-two subjects (103 men; aged 56.3 ± 9.8 years) underwent sequential chest radiographs during tidal breathing using dynamic chest radiography with a flat panel detector system. We evaluated the excursions of and peak motion speeds of the diaphragms. Associations between the excursions and participants' demographics (gender, height, weight, body mass index [BMI], smoking history, tidal volume, vital capacity, and forced expiratory volume) were investigated. The average excursion of the left diaphragm (14.9 ± 4.6 mm, 95% CI 14.2-15.5 mm) was significantly larger than that of the right (11.0 ± 4.0 mm, 95% CI 10.4-11.6 mm) (P <0.001). The peak motion speed of the left diaphragm (inspiratory, 16.6 ± 4.2 mm/s; expiratory, 13.7 ± 4.2 mm/s) was significantly faster than that of the right (inspiratory, 12.4 ± 4.4 mm/s; expiratory, 9.4 ± 3.8 mm/s) (both P <0.001). Both simple and multiple regression models demonstrated that higher BMI and higher tidal volume were associated with increased excursions of the bilateral diaphragm (all P <0.05). The average excursions of the diaphragms are 11.0 mm (right) and 14.9 mm (left) during tidal breathing in a standing position. The diaphragmatic motion of the left is significantly larger and faster than that of the right. Higher BMI and tidal volume are associated with increased excursions of the bilateral diaphragm. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  12. Paleomagnetic Results From the Pleistocene Sediments of Lomonosov Ridge, Central Artic Ocean, IODP Leg 302

    NASA Astrophysics Data System (ADS)

    King, J. W.; Heil, C.; O'Regan, M.; Moran, K.; Gattacecca, J.; Backman, J.; Jakobsson, M.; Moore, T.

    2005-12-01

    Two major conclusions can be drawn from magnetic studies of Pleistocene sediments drilled on Lomonosov Ridge, central Arctic Ocean during IODP Leg 302. The first conclusion is that central Arctic Ocean sedimentation rates approach 2 cm/ka during the Pleistocene, thereby resolving the Arctic sedimentation rate controversy in favor of "fast" rates. The second conclusion is that abundant broad intervals of reversed polarity during the Pleistocene are a consistent characteristic of Arctic sedimentary records. These broad reversed intervals have helped perpetuate the Arctic sedimentation rate controversy. The weight of evidence strongly indicates that these reversal intervals are excursions. They do not occur during the late Brunhes Epoch (approximately 0-250,000 BP), but occur during the mid to lower Brunhes Epoch and persist into the upper Matuyama Epoch. We observe a strong correlation between rock magnetic variations, color changes, and physical property stratigraphy and these excursions. The model for Arctic sedimentation indicates that the excursions primarily occur during "interglacial" intervals. Previous high quality paleomagnetic studies of Bermuda Rise sediments have shown that approximately 85 % of Brunhes age excursions occur during interglacial periods (Lund, et al., 2001). In addition, similar excursions do not appear to occur at high southern latitudes (e.g. Acton, et al., 2002). For these reasons, we feel that hypotheses that attribute the interesting observed Arctic paleomagnetic behavior to environmental controls (e.g. sedimentation processes) are favored over those involving geomagnetic field behavior within the tangent cylinder. Acton, G. D., Guyodo, Y., and S. A. Brachfeld, 2002. Magnetostratigraphy of sediment drifts on the continental rise of West Antarctica (ODP Leg 178, Sites 1095, 1096, and 1101). In Barker, P. F., Camerlenghi, A., Acton, G. D., and Ramsay, A.T.S (Eds.), Proc. ODP Sci. Results, v. 178; 1-61 (CD ROM). Lund, S. P., G. D. Acton, B. Clement, M. Okada, and T. Williams. 2001. Brunhes chron magnetics excursions recovered from Leg 172 sediments. In Keigwin, L. D., Rio, D., Acton, G. D., and Arnold, E., (eds.) Proc. ODP Sci. Results, v. 172; p. 1-18 (Online)

  13. Correlation of aptian-albian carbon isotope excursions in continental strata of the cretaceous Foreland Basin, Eastern Utah, U.S.A.

    USGS Publications Warehouse

    Ludvigson, Greg A.; Joeckel, R.M.; Gonzalez, Luis A.; Gulbranson, E.L.; Rasbury, E.T.; Hunt, G.J.; Kirkland, J.I.; Madsen, S.

    2010-01-01

    Nodular carbonates ("calcretes") in continental foreland-basin strata of the Early Cretaceous Cedar Mountain Formation (CMF) in eastern Utah yield ??13C and ??O records of changes in the exogenic carbon cycle related to oceanic anoxic events (OAEs), and terrestrial paleoclimate. Chemostratigraphic profiles of both forebulge and foredeep sections show two prominent positive ??13C excursions, each with a peak value of -3% VPDB, and having background ??13C values of about -6% VPDB. These excursions correlate with the global early Aptian (Ap7) and late Aptian-early Albian (Apl2-All) carbon isotope excursions. Aptian-Albian positive ??13C excursions in the CMF also correspond to 3-4 per mil increases in carbonate ??18O. These phenomena record local aridification events. The chemostratigraphic profile on the thinner forebulge section of the CMF is calibrated, for the first time, by a radiogenic U-Pb date of 119.4 ?? 2.6 Ma on a carbonate bed, and by detrital zircon U-Pb dates on two bounding sandstone units (maximum depositional ages of 146 Ma and 112 Ma). P??trographie observations and diagenetic analyses of micritic to microsparitic carbonates from nodules indicate palustrine origins and demonstrate that they crystallized in shallow early meteoric phreatic environments. Meteoric calcite lines derived from CMF carbonates have ??18O values ranging between -8.1 to -7.5%o VPDB, supporting an estimate of zonal mean groundwater ??18O of -6% VSMOW for an Aptian-Albian paleolatitude of 34?? N. Furthermore, our two chemostratigraphic profiles exhibit a generally proportionate thinning of correlative strata from the foredeep on to the forebulge, suggesting that there were consistently lower rates of accumulation on the forebulge during the Aptian-Albian. Identification of the global Aptian-Albian ??13C excursions in purely continental strata, as demonstrated in this paper, opens a new avenue of research by identifying specific stratigraphie intervals that record the terrestrial paleoclimatic impacts of perturbations of the global carbon cycle. Copyright ?? 2010, SEPM (Society for Sedimentary Geology).

  14. Sulfur isotope change across the Early Mississippian K-O (Kinderhookian-Osagean) δ13C excursion

    NASA Astrophysics Data System (ADS)

    Maharjan, Dev; Jiang, Ganqing; Peng, Yongbo; Nicholl, Michael J.

    2018-07-01

    Paired carbonate associate sulfate (CAS) sulfur isotopes (δ34SCAS), pyrite sulfur isotopes (δ34SPY) and CAS oxygen isotopes (δ18OCAS) across the Early Mississippian K-O δ13C excursion are documented from two sections of a west-dipping carbonate ramp in the southern Great Basin, western U.S.A. A 4-6‰ positive δ34SCAS anomaly, accompanied by negative shifts in δ34SPY and δ18OCAS, is found within the K-O δ13C excursion. In the section with a broader δ13C excursion, Δ34S (Δ34 S =δ34SCAS-δ34SPY) increases from 15‰ to 45‰ and δ13Ccarb drops from 7‰ to 4‰ at the same stratigraphic interval. If this δ34SCAS anomaly represents a global phenomenon, the large magnitude (4-6‰) and short duration (shorter than that of δ13C) suggest an unusual pyrite burial event that expanded from sediments to the ocean water column. In this scenario, the areal and volumetric expansion of sulfate reduction and pyrite burial was likely triggered by abundantly available organic matter near the peak of the K-O δ13C excursion, during which organic carbon production and burial may have reached a maximum, thus substantially expanding the oxygen minimum zone (OMZ). Numerical simulations suggest that pyrite burial rates 2.5-5 times higher than that of the modern ocean followed by sulfide oxidation are required to produce the observed δ34SCAS anomaly in a sulfate-rich ([SO4] ≥28 mM) Early Mississippian ocean. Alternatively, the sulfur and CAS oxygen isotope anomalies may record local sulfur cycling in a foreland basin where changes in weathering input and bottom-water redox conditions in response to sea-level fall and cooling resulted in isotope changes. In both scenarios (either local or global), the integrated carbon, sulfur, and CAS-oxygen isotope data suggest a much more dynamic sulfur cycle across the K-O δ13C excursion than has been previously suggested.

  15. Universal properties of knotted polymer rings.

    PubMed

    Baiesi, M; Orlandini, E

    2012-09-01

    By performing Monte Carlo sampling of N-steps self-avoiding polygons embedded on different Bravais lattices we explore the robustness of universality in the entropic, metric, and geometrical properties of knotted polymer rings. In particular, by simulating polygons with N up to 10(5) we furnish a sharp estimate of the asymptotic values of the knot probability ratios and show their independence on the lattice type. This universal feature was previously suggested, although with different estimates of the asymptotic values. In addition, we show that the scaling behavior of the mean-squared radius of gyration of polygons depends on their knot type only through its correction to scaling. Finally, as a measure of the geometrical self-entanglement of the self-avoiding polygons we consider the standard deviation of the writhe distribution and estimate its power-law behavior in the large N limit. The estimates of the power exponent do depend neither on the lattice nor on the knot type, strongly supporting an extension of the universality property to some features of the geometrical entanglement.

  16. Brain talk: power and negotiation in children's discourse about self, brain and behaviour.

    PubMed

    Singh, Ilina

    2013-07-01

    This article examines children's discourse about self, brain and behaviour, focusing on the dynamics of power, knowledge and responsibility articulated by children. The empirical data discussed in this article are drawn from the study of Voices on Identity, Childhood, Ethics and Stimulants, which included interviews with 151 US and UK children, a subset of whom had a diagnosis of attention deficit/hyperactivity disorder. Despite their contact with psychiatric explanations and psychotropic drugs for their behaviour, children's discursive engagements with the brain show significant evidence of agency and negotiated responsibility. These engagements suggest the limitations of current concepts that describe a collapse of the self into the brain in an age of neurocentrism. Empirical investigation is needed in order to develop agent-centred conceptual and theoretical frameworks that describe and evaluate the harms and benefits of treating children with psychotropic drugs and other brain-based technologies. © 2012 The Author. Sociology of Health & Illness © 2012 Foundation for the Sociology of Health & Illness/John Wiley & Sons Ltd.

  17. Effect of hamstring flexibility on hip and lumbar spine joint excursions during forward-reaching tasks in participants with and without low back pain.

    PubMed

    Johnson, Erica N; Thomas, James S

    2010-07-01

    To examine the correlation between hamstring flexibility and hip and lumbar spine joint excursions during standardized reaching and forward-bending tasks. Retrospective analysis of data obtained during 2 previous prospective studies that examined kinematics and kinetics during forward-reaching tasks in participants with and without low back pain (LBP). The 2 previous studies were conducted in the Motor Control Lab at Ohio University and the Orthopaedic Ergonomics Laboratory at The Ohio State University. Data from a total of 122 subjects from 2 previous studies: study 1: 86 subjects recovered from an episode of acute LBP (recovered) and study 2 (A.I. McCallum, unpublished data): 18 chronic LBP subjects and 18 healthy-matched controls (healthy). Not applicable. Correlation values between hamstring flexibility as measured by straight leg raise (SLR) and amount of hip and lumbar spine joint excursions used during standardized reaching and forward-bending tasks. No significant correlation was found between hamstring flexibility and hip and lumbar joint excursions during forward-bending tasks in the LBP or recovered groups. The SLR had a significant negative correlation with lumbar spine excursions during reaching tasks to a low target in the healthy group (right SLR: P=.011, left SLR: P=.004). Hamstring flexibility is not strongly related to the amount of lumbar flexion used to perform forward-reaching tasks in participants who have chronic LBP or who have recovered from LBP. More research needs to be conducted to examine the influence of hamstring flexibility on observed movement patterns to further evaluate the efficacy of flexibility training in the rehabilitation of patients with LBP. Copyright 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  18. Age and Structure of the Laschamp Geomagnetic Excursion

    NASA Astrophysics Data System (ADS)

    Scaillet, S.; Laj, C.; Kissel, C.; Guillou, H.; Singer, B. S.

    2004-12-01

    The age of the Laschamp geomagnetic excursion has been recently re-investigated using unspiked K/Ar and Ar/Ar techniques (Guillou et al., Session V01, this conference). The new age determination of 40.4 +/- 2.0 ka (2 sigma) is more precise than those previously reported in the literature and agrees precisely with that deduced from the GLOPIS-75 sedimentary paleointensity stack calibrated against the GISP2 ice core chronology. Two of the North Atlantic cores used in GLOPIS-75 (MD95-2034 and PS2644-5) yield rather detailed transitional VGP paths. In the two cases the paths show large similarities, with the VGP initially descending along mid-western Pacific, then returning to normal polarities with a large clockwise loop over Africa and Europe. Differences in the highest southern latitudes reached by the VGP can be explained assuming more different degrees of smearing of the paleomagnetic record due to differences in sedimentation rate in the two cores. In the most detailed record, MD95-2034 , two smaller loops are present preceding the main excursion. In the two cores, the excursion is characterized by a significant drop in intensity. The reversal paths observed for the Laschamp event are very close in position to those reported for the Icelandic Basin Event (IBE) from sites in the North Atlantic and the South China Sea (Laj et al., this conference) but differ in the sense of looping: while a clockwise loop is observed here, a counterclockwise loop is observed for the IBE. Despite this difference, the similarity of the transitional records tends to suggest that a similar, relatively simple, geometry has dominated the two excursions and therefore that similar dynamo mechanisms have prevailed during the reversal process.

  19. 40Ar/ 39Ar, K-Ar and 230Th- 238U dating of the Laschamp excursion: A radioisotopic tie-point for ice core and climate chronologies

    NASA Astrophysics Data System (ADS)

    Singer, Brad S.; Guillou, Hervé; Jicha, Brian R.; Laj, Carlo; Kissel, Catherine; Beard, Brian L.; Johnson, Clark M.

    2009-08-01

    A brief period of enhanced 10Be flux that straddles the interstadial warm period known as Dansgaard-Oeschger event 10 in Greenland and its counterpart in Antarctica, the Antarctic Isotope Maximum 10 is but one consequence of the weakening of Earth's magnetic field associated with the Laschamp excursion. This 10Be peak measured in the GRIP ice core is dated at 41,250 y b2k (= before year 2000 AD) in the most recent GICC05 age model obtained from the NorthGRIP core via multi-parameter counting of annual layers. Uncertainty in the age of the 10Be peak is, however, no better than ± 1630 y at the 95% confidence level, reflecting accumulated error in identifying annual layers. The age of the Laschamp excursion [Guillou, H., Singer, B.S., Laj, C., Kissel, C., Scaillet, S., Jicha, B., 2004. On the age of the Laschamp geomagnetic excursion. Earth Planet. Sci. Lett. 227, 331-343.] is revised on the basis of new 40Ar/ 39Ar, unspiked K-Ar and 238U- 230Th data from three lava flows in the Massif Central, France, together with the 40Ar/ 39Ar age of a transitionally magnetized lava flow at Auckland, New Zealand. Combined, these data yield an age of 40,700 ± 950 y b2k, where the uncertainty includes both analytical and systematic ( 40K and 230Th decay constant) errors. Taking the radioisotopic age as a calibration tie point suggests that the layer-counting chronologies for the NorthGRIP and GISP2 ice cores are more accurate and precise than previously thought at depths corresponding to the Laschamp excursion.

  20. Constraints on Early Triassic carbon cycle dynamics from paired organic and inorganic carbon isotope records

    NASA Astrophysics Data System (ADS)

    Meyer, K. M.; Yu, M.; Lehrmann, D.; van de Schootbrugge, B.; Payne, J. L.

    2013-01-01

    Large δ13C excursions, anomalous carbonate precipitates, low diversity assemblages of small fossils, and evidence for marine euxinia in uppermost Permian and Lower Triassic strata bear more similarity to Neoproterozoic carbonates than to the remainders of the Permian and Triassic systems. Middle Triassic diversification of marine ecosystems coincided with the waning of anoxia and stabilization of the global carbon cycle, suggesting that environment-ecosystem linkages were important to biological recovery. However, the Earth system behavior responsible for these large δ13C excursions remains poorly constrained. Here we present a continuous Early Triassic δ13Corg record from south China and use it to test the extent to which Early Triassic excursions in δ13Ccarb record changes in the δ13C of marine dissolved inorganic carbon (DIC). Regression analysis demonstrates a significant positive correlation between δ13Corg and δ13Ccarb across multiple sections that span a paleoenvironmental gradient. Such a correlation is incompatible with diagenetic alteration because no likely mechanism will alter both δ13Corg and δ13Ccarb records in parallel and therefore strongly indicates a primary depositional origin. A simple explanation for this correlation is that a substantial portion of the preserved Corg was derived from the contemporaneous DIC pool, implying that the observed excursions reflect variation in the δ13C of the exogenic carbon reservoir (ocean, atmosphere, biomass). These findings support existing evidence that large δ13C excursions are primary and therefore strengthen the case that large-scale changes to the carbon cycle were mechanistically linked to the low diversity and small size of Early Triassic fossils. Associated sedimentary and biogeochemical phenomena further suggest that similar associations in Neoproterozoic and Cambrian strata may reflect the same underlying controls.

  1. Agreement Between Visual Assessment and 2-Dimensional Analysis During Jump Landing Among Healthy Female Athletes.

    PubMed

    Rabin, Alon; Einstein, Ofira; Kozol, Zvi

    2018-04-01

      Altered movement patterns, including increased frontal-plane knee movement and decreased sagittal-plane hip and knee movement, have been associated with several knee disorders. Nevertheless, the ability of clinicians to visually detect such altered movement patterns during high-speed athletic tasks is relatively unknown.   To explore the association between visual assessment and 2-dimensional (2D) analysis of frontal-plane knee movement and sagittal-plane hip and knee movement during a jump-landing task among healthy female athletes.   Cross-sectional study.   Gymnasiums of participating volleyball teams.   A total of 39 healthy female volleyball players (age = 21.0 ± 5.2 years, height = 172.0 ± 8.6 cm, mass = 64.2 ± 7.2 kg) from Divisions I and II of the Israeli Volleyball Association.   Frontal-plane knee movement and sagittal-plane hip and knee movement during jump landing were visually rated as good, moderate, or poor based on previously established criteria. Frontal-plane knee excursion and sagittal-plane hip and knee excursions were measured using free motion-analysis software and compared among athletes with different visual ratings of the corresponding movements.   Participants with different visual ratings of frontal-plane knee movement displayed differences in 2D frontal-plane knee excursion ( P < .01), whereas participants with different visual ratings of sagittal-plane hip and knee movement displayed differences in 2D sagittal-plane hip and knee excursions ( P < .01).   Visual ratings of frontal-plane knee movement and sagittal-plane hip and knee movement were associated with differences in the corresponding 2D hip and knee excursions. Visual rating of these movements may serve as an initial screening tool for detecting altered movement patterns during jump landings.

  2. Eyelid reanimation with gold weight implant and tendon sling suspension: evaluation of excursion and velocity using the FACIAL CLIMA system.

    PubMed

    Hontanilla, Bernardo; Marre, Diego

    2013-04-01

    This study aims to analyse the efficacy of static techniques, namely gold weight implant and tendon sling, in the reanimation of the paralytic eyelid. Upper eyelid rehabilitation in terms of excursion and blinking velocity is performed using the automatic motion capture system, FACIAL CLIMA. Seventy-four patients underwent a total of 101 procedures including 58 upper eyelid gold weight implants and 43 lower eyelid tendon suspension with 27 patients undergoing both procedures. The presence of lagophtalmos, eye dryness, corneal ulcer, epiphora and lower lid ptosis/ectropion was assessed preoperatively. The Wilcoxon signed-rank test was used to compare preoperative versus postoperative measurements of upper eyelid excursion and blinking velocity determined with FACIAL CLIMA. Significance was set at p <0.05. FACIAL CLIMA revealed significant improvement of eyelid excursion and velocity of blinking (p < 0.001). Eye dryness improved in 49 patients (90.7%) and corneal ulcer resolved without any further treatment in 12 (85.7%) of those with a gold weight inserted. Implant extrusion was observed in 8.6% of the cases. Of the patients with lower lid tendon suspension, correction of ptosis/ectropion and epiphora was achieved in 93.9% and 91.9% of cases, respectively. In eight patients (18.6%), further surgery was needed to adjust tendon tension. The paralytic upper and lower eyelid can be successfully managed with gold weight implant and tendon suspension. The FACIAL CLIMA system is a reliable method to quantify upper eyelid excursion and blinking velocity and to detect the exact position of the lower eyelid. Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  3. Mandibular kinematic changes after unilateral cross-bite with lateral shift correction.

    PubMed

    Venancio, F; Alarcon, J A; Lenguas, L; Kassem, M; Martin, C

    2014-10-01

    The aim of this randomised prospective study was to evaluate the effects of slow maxillary expansion with expansion plates and Hyrax expanders on the kinematics of the mandible after cross-bite correction. Thirty children (15 boys and 15 girls), aged 7·1-11·8, with unilateral cross-bite and functional shift were divided into two groups: expansion plate (n = 15) and Hyrax expander (n = 15). Thirty children with normal occlusion (14 boys and 16 girls, aged 7·3-11·6) served as control group. The maximum vertical opening, lateral mandibular shift (from maximum vertical opening to maximum intercuspation, from rest position to maximum intercuspation and from maximum vertical opening to rest position) and lateral excursions were recorded before and 4 months after treatment. After treatment, the expansion plate group showed a greater lateral shift from rest position to maximum intercuspation than did the control group. The expansion plate patients also presented greater left/contralateral excursion than did the control group. Comparisons of changes after treatment in the cross-bite groups showed significant decreases in the lateral shift from the maximum vertical opening to maximum intercuspation and from the maximum vertical opening to rest position, a significant increase in the homolateral excursion and a significant decrease in the contralateral excursion in the Hyrax expander group, whereas no significant differences were found in the expansion plate group. In conclusion, the Hyrax expander showed better results than did the expansion plate. The Hyrax expander with acrylic occlusal covering significantly improved the mandibular lateral shift and normalised the range of lateral excursion. © 2014 John Wiley & Sons Ltd.

  4. Tonic Investigation Concept of Cervico-vestibular Muscle Afferents

    PubMed Central

    Dorn, Linda Josephine; Lappat, Annabelle; Neuhuber, Winfried; Scherer, Hans; Olze, Heidi; Hölzl, Matthias

    2016-01-01

    Introduction Interdisciplinary research has contributed greatly to an improved understanding of the vestibular system. To date, however, very little research has focused on the vestibular system's somatosensory afferents. To ensure the diagnostic quality of vestibular somatosensory afferent data, especially the extra cranial afferents, stimulation of the vestibular balance system has to be precluded. Objective Sophisticated movements require intra- and extra cranial vestibular receptors. The study's objective is to evaluate an investigation concept for cervico-vestibular afferents with respect to clinical feasibility. Methods A dedicated chair was constructed, permitting three-dimensional trunk excursions, during which the volunteer's head remains fixed. Whether or not a cervicotonic provocation nystagmus (c-PN) can be induced with static trunk excursion is to be evaluated and if this can be influenced by cervical monophasic transcutaneous electrical nerve stimulation (c-TENS) with a randomized test group. 3D-video-oculography (VOG) was used to record any change in cervico-ocular examination parameters. The occurring nystagmuses were evaluated visually due to the small caliber of nystagmus amplitudes in healthy volunteers. Results The results demonstrate: no influence of placebo-controlled c-TENS on the spontaneous nystagmus; a significant increase of the vertical nystagmus on the 3D-trunk-excursion chair in static trunk flexion with cervical provocation in all young healthy volunteers (n = 49); and a significant difference between vertical and horizontal nystagmuses during static trunk excursion after placebo-controlled c-TENS, except for the horizontal nystagmus during trunk torsion. Conclusion We hope this cervicotonic investigation concept on the 3D trunk-excursion chair will contribute to new diagnostic and therapeutic perspectives on cervical pathologies in vestibular head-to-trunk alignment. PMID:28050208

  5. Dosimetric Considerations in Respiratory-Gated Deep Inspiration Breath-Hold for Left Breast Irradiation.

    PubMed

    Walston, Steve; Quick, Allison M; Kuhn, Karla; Rong, Yi

    2017-02-01

    To present our clinical workflow of incorporating AlignRT for left breast deep inspiration breath-hold treatments and the dosimetric considerations with the deep inspiration breath-hold protocol. Patients with stage I to III left-sided breast cancer who underwent lumpectomy or mastectomy were considered candidates for deep inspiration breath-hold technique for their external beam radiation therapy. Treatment plans were created on both free-breathing and deep inspiration breath-hold computed tomography for each patient to determine whether deep inspiration breath-hold was beneficial based on dosimetric comparison. The AlignRT system was used for patient setup and monitoring. Dosimetric measurements and their correlation with chest wall excursion and increase in left lung volume were studied for free-breathing and deep inspiration breath-hold plans. Deep inspiration breath-hold plans had significantly increased chest wall excursion when compared with free breathing. This change in geometry resulted in reduced mean and maximum heart dose but did not impact lung V 20 or mean dose. The correlation between chest wall excursion and absolute reduction in heart or lung dose was found to be nonsignificant, but correlation between left lung volume and heart dose showed a linear association. It was also identified that higher levels of chest wall excursion may paradoxically increase heart or lung dose. Reduction in heart dose can be achieved for many left-sided breast and chest wall patients using deep inspiration breath-hold. Chest wall excursion as well as left lung volume did not correlate with reduction in heart dose, and it remains to be determined what metric will provide the most optimal and reliable dosimetric advantage.

  6. Multiple High-Frequency Carbon Isotope Excursions Across the Precambrian-Cambrian Boundary: Implications for Correlations and Environmental Change

    NASA Astrophysics Data System (ADS)

    Smith, E. F.; Macdonald, F. A.; Schrag, D. P.; Laakso, T.

    2014-12-01

    The GSSP Precambrian-Cambrian boundary in Newfoundland is defined by the first appearance datum (FAD) of Treptichnus pedum, which is considered to be roughly coincident with the FAD of small shelly fossils (SSFs) and a large negative carbon isotope excursion. An association between the FAD of T. pedum and a negative carbon isotope excursion has previously been documented in Northwest Canada (Narbonne et al., 1994) and Death Valley (Corsetti and Hagadorn, 2000), and since then has been used as an chronostratigraphic marker of the boundary, particularly in siliciclastic poor sections that do not preserve T. pedum. Here we present new high-resolution carbon isotope (δ13C ) chemostratigraphy from multiple sections in western Mongolia and the western United States that span the Ediacaran-Cambrian transition. High-resolution sampling (0.2-1 m) reveals that instead of one large negative excursion, there are multiple, high-frequency negative excursions with an overall negative trend during the latest Ediacaran. These data help to more precisely calibrate changes in the carbon cycle across the boundary as well as to highlight the potential problem of identifying the boundary with just a few negative δ13C values. We then use a simple carbon isotope box model to explore relationships between phosphorous delivery to the ocean, oxygenation, alkalinity, and turnovers in carbonate secreting organisms. Corsetti, F.A., and Hagadorn, J.W., 2000, Precambrian-Cambrian transition: Death Valley, United States: Geology, v. 28, no. 4, p. 299-302. Narbonne, G.M., Kaufman, A.J., and Knoll, A.H., 1994, Integrated chemostratigraphy and biostratigraphy of the Windermere Supergroup, northwestern Canada: Implications for Neoproterozoic correlations and the early evolution of animals: Geological Society of America Bulletin, v. 106, no. 10, p. 1281-1292.

  7. Teslaphoresis of Carbon Nanotubes.

    PubMed

    Bornhoeft, Lindsey R; Castillo, Aida C; Smalley, Preston R; Kittrell, Carter; James, Dustin K; Brinson, Bruce E; Rybolt, Thomas R; Johnson, Bruce R; Cherukuri, Tonya K; Cherukuri, Paul

    2016-04-26

    This paper introduces Teslaphoresis, the directed motion and self-assembly of matter by a Tesla coil, and studies this electrokinetic phenomenon using single-walled carbon nanotubes (CNTs). Conventional directed self-assembly of matter using electric fields has been restricted to small scale structures, but with Teslaphoresis, we exceed this limitation by using the Tesla coil's antenna to create a gradient high-voltage force field that projects into free space. CNTs placed within the Teslaphoretic (TEP) field polarize and self-assemble into wires that span from the nanoscale to the macroscale, the longest thus far being 15 cm. We show that the TEP field not only directs the self-assembly of long nanotube wires at remote distances (>30 cm) but can also wirelessly power nanotube-based LED circuits. Furthermore, individualized CNTs self-organize to form long parallel arrays with high fidelity alignment to the TEP field. Thus, Teslaphoresis is effective for directed self-assembly from the bottom-up to the macroscale.

  8. Investigation on Leaching Behaviour of Fly Ash and Bottom Ash Replacement in Self-Compacting Concrete

    NASA Astrophysics Data System (ADS)

    Kadir, Aeslina Abdul; Ikhmal Haqeem Hassan, Mohd; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    Fly ash and bottom ash are some of the waste generated by coal-fired power plants, which contains large quantities of toxic and heavy metals. In recent years, many researchers have been interested in studying on the properties of self-compacting concrete incorporated with fly ash and bottom ash but there was very limited research from the combination of fly ash and bottom ash towards the environmental needs. Therefore, this research was focused on investigating the leachability of heavy metals of SCC incorporated with fly ash and bottom ash by using Toxicity Characteristic Leaching Procedure, Synthetic Precipitation Leaching Procedure and Static Leaching Test. The samples obtained from the coal-fired power plant located at Peninsula, Malaysia. In this study, the potential heavy metals leached out from SCC that is produced with fly ash as a replacement for Ordinary Portland Cement and bottom ash as a substitute for sand with the ratios from 10% to 30% respectively were designated and cast. There are eight heavy metals of concern such as As, Cr, Pb, Zn, Cu, Ni, Mn and Fe. The results indicated that most of the heavy metals leached below the permissible limits from the United States Environmental Protection Agency and World Health Organization limit for drinking water. As a conclusion, the minimum leaching of the heavy metals from the incorporation of fly ash and bottom ash in self-compacting concrete was found in 20% of fly ash and 20% of bottom ash replacement. The results also indicate that this incorporation could minimize the potential of environmental problems.

  9. Analytical and simulator study of advanced transport

    NASA Technical Reports Server (NTRS)

    Levison, W. H.; Rickard, W. W.

    1982-01-01

    An analytic methodology, based on the optimal-control pilot model, was demonstrated for assessing longitidunal-axis handling qualities of transport aircraft in final approach. Calibration of the methodology is largely in terms of closed-loop performance requirements, rather than specific vehicle response characteristics, and is based on a combination of published criteria, pilot preferences, physical limitations, and engineering judgment. Six longitudinal-axis approach configurations were studied covering a range of handling qualities problems, including the presence of flexible aircraft modes. The analytical procedure was used to obtain predictions of Cooper-Harper ratings, a solar quadratic performance index, and rms excursions of important system variables.

  10. Dynamic Reconfiguration of Security Policies in Wireless Sensor Networks

    PubMed Central

    Pinto, Mónica; Gámez, Nadia; Fuentes, Lidia; Amor, Mercedes; Horcas, José Miguel; Ayala, Inmaculada

    2015-01-01

    Providing security and privacy to wireless sensor nodes (WSNs) is very challenging, due to the heterogeneity of sensor nodes and their limited capabilities in terms of energy, processing power and memory. The applications for these systems run in a myriad of sensors with different low-level programming abstractions, limited capabilities and different routing protocols. This means that applications for WSNs need mechanisms for self-adaptation and for self-protection based on the dynamic adaptation of the algorithms used to provide security. Dynamic software product lines (DSPLs) allow managing both variability and dynamic software adaptation, so they can be considered a key technology in successfully developing self-protected WSN applications. In this paper, we propose a self-protection solution for WSNs based on the combination of the INTER-TRUST security framework (a solution for the dynamic negotiation and deployment of security policies) and the FamiWare middleware (a DSPL approach to automatically configure and reconfigure instances of a middleware for WSNs). We evaluate our approach using a case study from the intelligent transportation system domain. PMID:25746093

  11. How to assess good candidate molecules for self-activated optical power limiting

    NASA Astrophysics Data System (ADS)

    Lundén, Hampus; Glimsdal, Eirik; Lindgren, Mikael; Lopes, Cesar

    2018-03-01

    Reverse saturable absorbers have shown great potential to attenuate laser radiation. Good candidate molecules and various particles have successfully been incorporated into different glass matrices, enabling the creation of self-activated filters against damaging laser radiation. Although the performance of such filters has been impressive, work is still ongoing to improve the performance in a wider range of wavelengths and pulse widths. The purpose of this tutorial is, from an optical engineering perspective, to give an understanding of the strengths and weaknesses of this class of smart materials, how relevant photophysical parameters are measured and influence system performance and comment on the pitfalls in experimental evaluation of materials. A numerical population model in combination with simple physical formulas is used to demonstrate system behavior from a performance standpoint. Geometrical reasoning shows the advantage of reverse saturable absorption over nonlinear scattering due to a fraction of scattered light being recollected by imaging system optics. The numerical population model illustrates the importance of the optical power limiting performance during the leading edge of a nanosecond pulse, which is most strongly influenced by changes in the two-photon absorption cross section and the triplet linear absorption cross section for a modeled Pt-acetylide. This tutorial not only targets optical engineers evaluating reverse saturable absorbing materials but also aims to assist researchers with a chemistry background working on optical power limiting materials. We also present photophysical data for a series of coumarins that can be useful for the determination of quantum yields and two-photon cross sections and show examples of characterization of molecules with excited triplet states.

  12. Recognizing the Albian-Cenomanian (OAE1d) sequence boundary using plant carbon isotopes: Dakota Formation, Western Interior Basin, USA

    USGS Publications Warehouse

    Grocke, D.R.; Ludvigson, Greg A.; Witzke, B.L.; Robinson, S.A.; Joeckel, R.M.; Ufnar, David F.; Ravn, R.L.

    2006-01-01

    Analysis of bulk sedimentary organic matter and charcoal from an Albian-Cenomanian fluvial-estuarine succession (Dakota Formation) at Rose Creek Pit (RCP), Nebraska, reveals a negative excursion of ???3???, in late Albian strata. Overlying Cenomanian strata have ??13C values of -24???, to -23???, that are similar to pre-excursion values. The absence of an intervening positive excursion (as exists in marine records of the Albian-Cenomanian boundary) likely results from a depositional hiatus. The corresponding positive ??13C event and proposed depositional hiatus are concordant with a regionally identified sequence boundary in the Dakota Formation (D2), as well as a major regressive phase throughout the globe at the Albian-Cenomanian boundary. Data from RCP confirm suggestions that some positive carbon-isotope excursions in the geologic record are coincident with regressive sea-level phases. We estimate using isotopic correlation that the D2 sequence boundary at RCP was on the order of 0.5 m.y. in duration. Therefore, interpretations of isotopic events and associated environmental phenomena, such as oceanic anoxic events, in the shallow-marine and terrestrial record may be influenced by stratigraphic incompleteness. Further investigation of terrestrial ??13C records may be useful in recognizing and constraining sea-level changes in the geologic record. ?? 2006 Geological Society of America.

  13. The Laschamp geomagnetic excursion featured in nitrate record from EPICA-Dome C ice core

    PubMed Central

    Traversi, R.; Becagli, S.; Poluianov, S.; Severi, M.; Solanki, S. K.; Usoskin, I. G.; Udisti, R.

    2016-01-01

    Here we present the first direct comparison of cosmogenic 10Be and chemical species in the period of 38–45.5 kyr BP spanning the Laschamp geomagnetic excursion from the EPICA-Dome C ice core. A principal component analysis (PCA) allowed to group different components as a function of the main sources, transport and deposition processes affecting the atmospheric aerosol at Dome C. Moreover, a wavelet analysis highlighted the high coherence and in-phase relationship between 10Be and nitrate at this time. The evident preferential association of 10Be with nitrate rather than with other chemical species was ascribed to the presence of a distinct source, here labelled as “cosmogenic”. Both the PCA and wavelet analyses ruled out a significant role of calcium in driving the 10Be and nitrate relationship, which is particularly relevant for a plateau site such as Dome C, especially in the glacial period during which the Laschamp excursion took place. The evidence that the nitrate record from the EDC ice core is able to capture the Laschamp event hints toward the possibility of using this marker for studying galactic cosmic ray flux variations and thus also major geomagnetic field excursions at pluri-centennial-millennial time scales, thus opening up new perspectives in paleoclimatic studies. PMID:26819064

  14. A reassessment of the role of tidal dispersion in estuaries and bays

    USGS Publications Warehouse

    Geyer, W. Rockwell; Signell, Richard P.

    1992-01-01

    The role of tidal dispersion is reassessed, based on a consideration of the relevant physical mechanisms, particularly those elucidated by numerical simulations of tide-induced dispersion. It appears that the principal influence of tidal currents on dispersion occurs at length scales of the tidal excursion and smaller; thus the effectiveness of tidal dispersion depends on the relative scale of the tidal excursion to the spacing between major bathymetric and shoreline features. In estuaries where the typical spacing of topographic features is less than the tidal excursion, tidal dispersion may contribute significantly to the overall flushing. In estuaries and embayments in which the typical spacing between major features is larger than the tidal excursion, the influence of tidal dispersion will be localized, and it will not markedly contribute to overall flushing. Tidal dispersion is most pronounced in regions of abrupt topographic changes such as headlands and inlets, where flow separation occurs. The strong strain rate in the region of flow separation tends to stretch patches of fluid into long filaments, which are subsequently rolled up and distorted by the transient eddy field. The dispersion process accomplished by the tides varies strongly as a function of position and tidal phase and thus does not lend itself to parameterization by an eddy diffusion coefficient.

  15. A Geograns update. New experiences to teach earth sciences to students older than 55

    NASA Astrophysics Data System (ADS)

    Cerdà, A.; Pinazo, S.

    2009-04-01

    How to teach earth science to students that have access to the university after the age of 55 is a challenge due to the different background of the students. They ranged from those with only basic education (sometimes they finished school at the age of 9) to well educate students such as university professors, physicians or engineers. Students older than 55 are enrolled in what is called the university programme NauGran project at the University of Valencia. They follow diverse topics, from health science to Arts. Since 2006 the Department of Geography and the NauGran project developed the Club for Geographers and Walkers called Geograns. The objective is to teach Earth Science in the field as a strategy to improve the knowledge of the students with a direct contact with the territory. This initiative reached a successful contribution by the students, with 70 students registered. The successful strategy we have developed since then is to base our teaching on field work. Every lecture is related to some visits to the field. A pre-excursion lecture introduces the key questions of the study site (hydrology, geology, botany, geomorphology…). During the field work we review all the topics and the students are encouraged to ask and discuss any of the topics studied. Finally, a post-excursion lecture is given to review the acquired knowledge. During the last academic year 2007-2008 the excursion focussed on: (i) energy sources: problems and solutions, with visit to nuclear, wind and hydraulic power stations; (i) human disturbances and humankind as landscaper, with visits to wetlands, river gorges and Iberian settlements; and (iii) human activities and economical resources, with visits to vineyards and wineries and orange fields devoted to organic farming. This is being a positive strategy to teach Earth Science to a wide and heterogeneous group of students, as they improve their knowledge with a direct contact with the landscape, other colleagues and teachers in the field. Key Words: Teaching, Earth Science, Field work, Earth Science, Environment.

  16. Anterior Aortic Plane Systolic Excursion: A Novel Indicator of Transplant-Free Survival in Systemic Light-Chain Amyloidosis.

    PubMed

    Ochs, Marco M; Riffel, Johannes; Kristen, Arnt V; Hegenbart, Ute; Schönland, Stefan; Hardt, Stefan E; Katus, Hugo A; Mereles, Derliz; Buss, Sebastian J

    2016-12-01

    Anterior aortic plane systolic excursion (AAPSE) was evaluated in the present pilot study as a novel echocardiographic indicator of transplant-free survival in patients with systemic light-chain amyloidosis. Eighty-nine patients with light-chain amyloidosis were included in the post-hoc analysis. A subgroup of 54 patients with biopsy-proven cardiac amyloid infiltration were compared with 41 healthy individuals to evaluate the discriminative ability of echocardiographic findings. AAPSE is defined as the systolic excursion of the anterior aortic margin. To quantify AAPSE, the M-mode cursor was placed on the aortic valve plane in parasternal long-axis view at end-diastole. Index echocardiography had been performed before chemotherapy. Median follow-up duration was 2.4 years. The primary combined end point was heart transplantation or overall death. Mean AAPSE was 14 ± 2 mm in healthy individuals (mean age=57 ± 10 years; 56% men; BMI=25 ± 4 kg/m 2 ). AAPSE < 11 mm separated patients from age-, gender-, and BMI-matched control subjects with 93% sensitivity and 97% specificity. Median transplant-free survival of patients with AAPSE < 5 mm was 0.7 versus 4.8 years (P = .0001). AAPSE was an independent indicator of transplant-free survival in multivariate Cox regression (echocardiographic model: hazard ratio=0.72 [P = .03]; biomarker model: hazard ratio=0.62 [P = .0001]). Sequential regression analysis suggested incremental power of AAPSE as a marker of transplant-free survival. An ejection fraction-based model with an overall χ 2 value of 22.8 was improved by the addition of log NT-proBNP (χ 2  = 32.6, P < .005), troponin-T (χ 2  = 39.6, P < .01), and AAPSE (χ 2  = 54.0, P < .0001). AAPSE is suggested as an indicator of transplant-free survival in patients with systemic light-chain amyloidosis. AAPSE provided significant incremental value to established staging models. Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  17. Indian Postsecondary Education and the Law.

    ERIC Educational Resources Information Center

    Locke, Patricia

    Postsecondary education and all of Indian education are tied to the tribes, the complexities of Indian law, and the tribal powers of self-government which in turn are based on treaties with the U.S. government. Since 1789, treaty relations were entered with nearly every tribe and band within the U.S. territorial limits. Part of the consideration…

  18. 76 FR 56833 - Self-Regulatory Organizations; BATS Y-Exchange, Inc.; Notice of Filing of Proposed Rule Change To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... respective voting rights and of Class A and Class B common stock, (iv) setting forth certain limitations on... Incorporation, shares of Non-Voting Common Stock possess the same rights, preferences, powers, privileges... B Common Stock. Except for voting rights and certain conversion features, as described below, Class...

  19. 76 FR 56840 - Self-Regulatory Organizations; BATS Exchange, Inc.; Notice of Filing of Proposed Rule Change To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... respective voting rights and of Class A and Class B common stock, (iv) setting forth certain limitations on... Incorporation, shares of Non-Voting Common Stock possess the same rights, preferences, powers, privileges...-Voting Class B Common Stock. Except for voting rights and certain conversion features, as described below...

  20. Interventions to address unequal gender and power relations and improve self-efficacy and empowerment for sexual and reproductive health decision-making for women living with HIV: A systematic review

    PubMed Central

    Robinson, Jennifer L.; Narasimhan, Manjulaa; Amin, Avni; Morse, Sophie; Beres, Laura K.; Kennedy, Caitlin Elizabeth

    2017-01-01

    Background Many women living with HIV experience gendered power inequalities, particularly in their intimate relationships, that prevent them from achieving optimal sexual and reproductive health (SRH) and exercising their rights. We assessed the effectiveness of interventions to improve self-efficacy and empowerment of women living with HIV to make SRH decisions through a systematic review. Methods and findings We included peer-reviewed articles indexed in PubMed, PsycINFO, CINAHL, Embase, and Scopus published through January 3, 2017, presenting multi-arm or pre-post intervention evaluations measuring one of the following outcomes: (1) self-efficacy, empowerment, or measures of SRH decision-making ability, (2) SRH behaviors (e.g., condom use, contraceptive use), or (3) SRH outcomes (e.g., sexually transmitted infections [STIs]). Twenty-one studies evaluating 11 intervention approaches met the inclusion criteria. All were conducted in the United States or sub-Saharan Africa. Two high-quality randomized controlled trials (RCTs) showed significant decreases in incident gonorrhea and chlamydia. Sixteen studies measuring condom use generally found moderate increases associated with the intervention, including in higher-quality RCTs. Findings on contraceptive use, condom self-efficacy, and other empowerment measures (e.g., sexual communication, equitable relationship power) were mixed. Studies were limited by small sample sizes, high loss to follow-up, and high reported baseline condom use. Conclusions While more research is needed, the limited existing evidence suggests that these interventions may help support the SRH and rights of women living with HIV. This review particularly highlights the importance of these interventions for preventing STIs, which present a significant health burden for women living with HIV that is rarely addressed holistically. Empowerment-based interventions should be considered as part of a comprehensive package of STI and other SRH services for women living with HIV. PMID:28837562

  1. Interventions to address unequal gender and power relations and improve self-efficacy and empowerment for sexual and reproductive health decision-making for women living with HIV: A systematic review.

    PubMed

    Robinson, Jennifer L; Narasimhan, Manjulaa; Amin, Avni; Morse, Sophie; Beres, Laura K; Yeh, Ping Teresa; Kennedy, Caitlin Elizabeth

    2017-01-01

    Many women living with HIV experience gendered power inequalities, particularly in their intimate relationships, that prevent them from achieving optimal sexual and reproductive health (SRH) and exercising their rights. We assessed the effectiveness of interventions to improve self-efficacy and empowerment of women living with HIV to make SRH decisions through a systematic review. We included peer-reviewed articles indexed in PubMed, PsycINFO, CINAHL, Embase, and Scopus published through January 3, 2017, presenting multi-arm or pre-post intervention evaluations measuring one of the following outcomes: (1) self-efficacy, empowerment, or measures of SRH decision-making ability, (2) SRH behaviors (e.g., condom use, contraceptive use), or (3) SRH outcomes (e.g., sexually transmitted infections [STIs]). Twenty-one studies evaluating 11 intervention approaches met the inclusion criteria. All were conducted in the United States or sub-Saharan Africa. Two high-quality randomized controlled trials (RCTs) showed significant decreases in incident gonorrhea and chlamydia. Sixteen studies measuring condom use generally found moderate increases associated with the intervention, including in higher-quality RCTs. Findings on contraceptive use, condom self-efficacy, and other empowerment measures (e.g., sexual communication, equitable relationship power) were mixed. Studies were limited by small sample sizes, high loss to follow-up, and high reported baseline condom use. While more research is needed, the limited existing evidence suggests that these interventions may help support the SRH and rights of women living with HIV. This review particularly highlights the importance of these interventions for preventing STIs, which present a significant health burden for women living with HIV that is rarely addressed holistically. Empowerment-based interventions should be considered as part of a comprehensive package of STI and other SRH services for women living with HIV.

  2. Subtle Nonlinearity in Popular Album Charts

    NASA Astrophysics Data System (ADS)

    Bentley, R. Alexander; Maschner, Herbert D. G.

    Large-scale patterns of culture change may be explained by models of self organized criticality, or alternatively, by multiplicative processes. We speculate that popular album activity may be similar to critical models of extinction in that interconnected agents compete to survive within a limited space. Here we investigate whether popular music albums as listed on popular album charts display evidence of self-organized criticality, including a self-affine time series of activity and power-law distributions of lifetimes and exit activity in the chart. We find it difficult to distinguish between multiplicative growth and critical model hypotheses for these data. However, aspects of criticality may be masked by the selective sampling that a "Top 200" listing necessarily implies.

  3. Self-phase modulation enabled, wavelength-tunable ultrafast fiber laser sources: an energy scalable approach.

    PubMed

    Liu, Wei; Li, Chen; Zhang, Zhigang; Kärtner, Franz X; Chang, Guoqing

    2016-07-11

    We propose and demonstrate a new approach to implement a wavelength-tunable ultrafast fiber laser source suitable for multiphoton microscopy. We employ fiber-optic nonlinearities to broaden a narrowband optical spectrum generated by an Yb-fiber laser system and then use optical bandpass filters to select the leftmost or rightmost spectral lobes from the broadened spectrum. Detailed numerical modeling shows that self-phase modulation dominates the spectral broadening, self-steepening tends to blue shift the broadened spectrum, and stimulated Raman scattering is minimal. We also find that optical wave breaking caused by fiber dispersion slows down the shift of the leftmost/rightmost spectral lobes and therefore limits the wavelength tuning range of the filtered spectra. We show both numerically and experimentally that shortening the fiber used for spectral broadening while increasing the input pulse energy can overcome this dispersion-induced limitation; as a result, the filtered spectral lobes have higher power, constituting a powerful and practical approach for energy scaling the resulting femtosecond sources. We use two commercially available photonic crystal fibers to verify the simulation results. More specific, use of 20-mm fiber NL-1050-ZERO-2 enables us to implement an Yb-fiber laser based ultrafast source, delivering femtosecond (70-120 fs) pulses tunable from 825 nm to 1210 nm with >1 nJ pulse energy.

  4. Statistical signal analysis of the Phanerozoic ð13C curve: implications for Earth system evolution

    NASA Astrophysics Data System (ADS)

    Bachan, A.; Kump, L. R.; Payne, J.; Saltzman, M.; Thomas, E.

    2014-12-01

    In recent years, vast amounts of carbon isotopic data have been collected allowing the construction of the Phanerozoic δ13C curve in unprecedented detail. Our dataset comprises 8143 points spanning the last 541 m.y., with a mean spacing of 66 k.y. The average δ13C of Phanerozoic carbonate is 1 ‰ ± 2 ‰, in accordance with the canonical values measured in the past. However, the record also shows numerous, highly resolved, large (± 6 ‰) excursions whose magnitude declines through time, especially going into the late Mesozoic and Cenozoic. When the magnitude - distribution of the excursions is tabulated we find that it follows a power law: plotting the min-max differences vs. number of bins in which a particular value occurs reveals that the data fall on a semilogarithmic line with a slope of -0.23 and R2 = 0.99. The result is insensitive to outliers: smoothing the data with lowess, spline, Savitzky-Golay, and Butterworth filters yields similar results. The continuity from small variation to large perturbations, both positive and negative, suggests that, despite the numerous proposed causes for individual carbon isotopic evens, there is likely an underlying mechanism which governs the magnitude of δ13C response to perturbations. We suggest that a mechanism acting to amplify carbon cycle perturbations is the key to explaining the power-law distribution, and identify the anoxia-productivity feedback as the most likely candidate. Establishment of sulfidic conditions is accompanied by increased release of phosphate to the water column, which allows for further productivity, and thus acts as a destabilizing, positive, feedback. This feedback would act to increase carbon cycle swings irrespective of their proximal trigger. The decline in frequency of anoxic-sulfidic bottom waters in the world's oceans, and potential disappearance in the Late Mesozoic-Cenozoic, may account for a reduction in the Earth system's gain and increase in its resilience.

  5. New Evidence on Self-Affirmation Effects and Theorized Sources of Heterogeneity from Large-Scale Replications

    PubMed Central

    Hanselman, Paul; Rozek, Christopher S.; Grigg, Jeffrey; Borman, Geoffrey D.

    2016-01-01

    Brief, targeted self-affirmation writing exercises have recently been offered as a way to reduce racial achievement gaps, but evidence about their effects in educational settings is mixed, leaving ambiguity about the likely benefits of these strategies if implemented broadly. A key limitation in interpreting these mixed results is that they come from studies conducted by different research teams with different procedures in different settings; it is therefore impossible to isolate whether different effects are the result of theorized heterogeneity, unidentified moderators, or idiosyncratic features of the different studies. We addressed this limitation by conducting a well-powered replication of self-affirmation in a setting where a previous large-scale field experiment demonstrated significant positive impacts, using the same procedures. We found no evidence of effects in this replication study and estimates were precise enough to reject benefits larger than an effect size of 0.10. These null effects were significantly different from persistent benefits in the prior study in the same setting, and extensive testing revealed that currently theorized moderators of self-affirmation effects could not explain the difference. These results highlight the potential fragility of self-affirmation in educational settings when implemented widely and the need for new theory, measures, and evidence about the necessary conditions for self-affirmation success. PMID:28450753

  6. What are the ultimate limits to computational techniques: verifier theory and unverifiability

    NASA Astrophysics Data System (ADS)

    Yampolskiy, Roman V.

    2017-09-01

    Despite significant developments in proof theory, surprisingly little attention has been devoted to the concept of proof verifiers. In particular, the mathematical community may be interested in studying different types of proof verifiers (people, programs, oracles, communities, superintelligences) as mathematical objects. Such an effort could reveal their properties, their powers and limitations (particularly in human mathematicians), minimum and maximum complexity, as well as self-verification and self-reference issues. We propose an initial classification system for verifiers and provide some rudimentary analysis of solved and open problems in this important domain. Our main contribution is a formal introduction of the notion of unverifiability, for which the paper could serve as a general citation in domains of theorem proving, as well as software and AI verification.

  7. A Bearingless Switched-Reluctance Motor for High Specific Power Applications

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin B.; Siebert, Mark

    2006-01-01

    A 12-8 switched-reluctance motor (SRM) is studied in bearingless (or self-levitated) operation with coil currents limited to the linear region to avoid magnetic saturation. The required motoring and levitating currents are summed and go into a single motor coil per pole to obtain the highest power output of the motor by having more space for motor coil winding. Two controllers are investigated for the bearingless SRM operation. First, a model-based controller using the radial force, which is adjusted by a factor derived from finite element analysis, is presented. Then a simple and practical observation-based controller using a PD (proportional-derivative) control algorithm is presented. Both controllers were experimentally demonstrated to 6500 rpm. This paper reports the initial efforts toward eventual self levitation of a SRM operating into strong magnetic core saturation at liquid nitrogen temperature.

  8. Power Laws, Scale Invariance and the Generalized Frobenius Series:

    NASA Astrophysics Data System (ADS)

    Visser, Matt; Yunes, Nicolas

    We present a self-contained formalism for calculating the background solution, the linearized solutions and a class of generalized Frobenius-like solutions to a system of scale-invariant differential equations. We first cast the scale-invariant model into its equidimensional and autonomous forms, find its fixed points, and then obtain power-law background solutions. After linearizing about these fixed points, we find a second linearized solution, which provides a distinct collection of power laws characterizing the deviations from the fixed point. We prove that generically there will be a region surrounding the fixed point in which the complete general solution can be represented as a generalized Frobenius-like power series with exponents that are integer multiples of the exponents arising in the linearized problem. While discussions of the linearized system are common, and one can often find a discussion of power-series with integer exponents, power series with irrational (indeed complex) exponents are much rarer in the extant literature. The Frobenius-like series we encounter can be viewed as a variant of the rarely-discussed Liapunov expansion theorem (not to be confused with the more commonly encountered Liapunov functions and Liapunov exponents). As specific examples we apply these ideas to Newtonian and relativistic isothermal stars and construct two separate power series with the overlapping radius of convergence. The second of these power series solutions represents an expansion around "spatial infinity," and in realistic models it is this second power series that gives information about the stellar core, and the damped oscillations in core mass and core radius as the central pressure goes to infinity. The power-series solutions we obtain extend classical results; as exemplified for instance by the work of Lane, Emden, and Chandrasekhar in the Newtonian case, and that of Harrison, Thorne, Wakano, and Wheeler in the relativistic case. We also indicate how to extend these ideas to situations where fixed points may not exist — either due to "monotone" flow or due to the presence of limit cycles. Monotone flow generically leads to logarithmic deviations from scaling, while limit cycles generally lead to discrete self-similar solutions.

  9. Every Good Virtue You Ever Wanted in a Q-switched Solid-state Laser and More: Monolithic, Diode-pumped, Self-q-switched, Highly Reproducible, Diffraction-limited Nd:yag Laser

    NASA Technical Reports Server (NTRS)

    Chen, Y. C.; Lee, K. K.

    1993-01-01

    The applications of Q-switched lasers are well known, for example, laser radar, laser remote sensing, satellite orbit determination, Moon orbit and 'moon quake' determination, satellite laser communication, and many nonlinear optics applications. Most of the applications require additional properties of the Q-switched lasers, such as single-axial and/or single-transverse mode, high repetition rate, stable pulse shape and pulse width, or ultra compact and rugged oscillators. Furthermore, space based and airborne lasers for lidar and laser communication applications require efficient, compact, lightweight, long-lived, and stable-pulsed laser sources. Diode-pumped solid-state lasers (DPSSL) have recently shown the potential for satisfying all of these requirements. We will report on the operating characteristics of a diode-pumped, monolithic, self-Q-switched Cr,Nd:YAG laser where the chromium ions act as a saturable absorber for the laser emission at 1064 nm. The pulse duration is 3.5 ns and the output is highly polarized with an extinction ratio of 700:1. It is further shown that the output is single-longitudinal-mode with transform-limited spectral line width without pulse-to-pulse mode competition. Consequently, the pulse-to-pulse intensity fluctuation is less than the instrument resolution of 0.25 percent. This self-stabilization mechanism is because the lasing mode bleaches the distributed absorber and establishes a gain-loss grating similar to that used in the distributed feedback semiconductor lasers. A repetition rate above 5 KHz has also been demonstrated. For higher power, this laser can be used for injection seeding an amplifier (or amplifier chain) or injection locking of a power oscillator pumped by diode lasers. We will discuss some research directions on the master oscillator for higher output energy per pulse as well as how to scale the output power of the diode-pumped amplifier(s) to multi-kilowatt average power.

  10. Interconnect patterns for printed organic thermoelectric devices with large fill factors

    NASA Astrophysics Data System (ADS)

    Gordiz, Kiarash; Menon, Akanksha K.; Yee, Shannon K.

    2017-09-01

    Organic materials can be printed into thermoelectric (TE) devices for low temperature energy harvesting applications. The output voltage of printed devices is often limited by (i) small temperature differences across the active materials attributed to small leg lengths and (ii) the lower Seebeck coefficient of organic materials compared to their inorganic counterparts. To increase the voltage, a large number of p- and n-type leg pairs is required for organic TEs; this, however, results in an increased interconnect resistance, which then limits the device output power. In this work, we discuss practical concepts to address this problem by positioning TE legs in a hexagonal closed-packed layout. This helps achieve higher fill factors (˜91%) than conventional inorganic devices (˜25%), which ultimately results in higher voltages and power densities due to lower interconnect resistances. In addition, wiring the legs following a Hilbert spacing-filling pattern allows for facile load matching to each application. This is made possible by leveraging the fractal nature of the Hilbert interconnect pattern, which results in identical sub-modules. Using the Hilbert design, sub-modules can better accommodate non-uniform temperature distributions because they naturally self-localize. These device design concepts open new avenues for roll-to-roll printing and custom TE module shapes, thereby enabling organic TE modules for self-powered sensors and wearable electronic applications.

  11. Electricity and disinfectant production from wastewater: Microbial Fuel Cell as a self-powered electrolyser

    NASA Astrophysics Data System (ADS)

    Gajda, Iwona; Greenman, John; Melhuish, Chris; Ieropoulos, Ioannis A.

    2016-05-01

    This study presents a simple and sustainable Microbial Fuel Cell as a standalone, self-powered reactor for in situ wastewater electrolysis, recovering nitrogen from wastewater. A process is proposed whereby the MFC electrical performance drives the electrolysis of wastewater towards the self-generation of catholyte within the same reactor. The MFCs were designed to harvest the generated catholyte in the internal chamber, which showed that liquid production rates are largely proportional to electrical current generation. The catholyte demonstrated bactericidal properties, compared to the control (open-circuit) diffusate, and reduced observable biofilm formation on the cathode electrode. Killing effects were confirmed using bacterial kill curves constructed by exposing a bioluminescent Escherichia coli target, as a surrogate coliform, to catholyte where a rapid kill rate was observed. Therefore, MFCs could serve as a water recovery system, a disinfectant/cleaner generator that limits undesired biofilm formation and as a washing agent in waterless urinals to improve sanitation. This simple and ready to implement MFC system can convert organic waste directly into electricity and self-driven nitrogen along with water recovery. This could lead to the development of energy positive bioprocesses for sustainable wastewater treatment.

  12. Electricity and disinfectant production from wastewater: Microbial Fuel Cell as a self-powered electrolyser

    PubMed Central

    Gajda, Iwona; Greenman, John; Melhuish, Chris; Ieropoulos, Ioannis A.

    2016-01-01

    This study presents a simple and sustainable Microbial Fuel Cell as a standalone, self-powered reactor for in situ wastewater electrolysis, recovering nitrogen from wastewater. A process is proposed whereby the MFC electrical performance drives the electrolysis of wastewater towards the self-generation of catholyte within the same reactor. The MFCs were designed to harvest the generated catholyte in the internal chamber, which showed that liquid production rates are largely proportional to electrical current generation. The catholyte demonstrated bactericidal properties, compared to the control (open-circuit) diffusate, and reduced observable biofilm formation on the cathode electrode. Killing effects were confirmed using bacterial kill curves constructed by exposing a bioluminescent Escherichia coli target, as a surrogate coliform, to catholyte where a rapid kill rate was observed. Therefore, MFCs could serve as a water recovery system, a disinfectant/cleaner generator that limits undesired biofilm formation and as a washing agent in waterless urinals to improve sanitation. This simple and ready to implement MFC system can convert organic waste directly into electricity and self-driven nitrogen along with water recovery. This could lead to the development of energy positive bioprocesses for sustainable wastewater treatment. PMID:27172836

  13. Working and Learning in a Field Excursion.

    PubMed

    Hole, Torstein Nielsen

    2018-06-01

    This study aimed to discern sociocultural processes through which students learn in field excursions. To achieve this aim, short-term ethnographic techniques were employed to examine how undergraduate students work and enact knowledge (or knowing) during a specific field excursion in biology. The students participated in a working practice that employed research methods and came to engage with various biological phenomena over the course of their work. A three-level analysis of the students' experiences focused on three processes that emerged: participatory appropriation, guided participation, and apprenticeship. These processes derive from advances in practice-oriented theories of knowing. Through their work in the field, the students were able to enact science autonomously; they engaged with peers and teachers in specific ways and developed new understandings about research and epistemology founded on their experiences in the field. Further discussion about the use of "practice" and "work" as analytical concepts in science education is also included.

  14. Turbulence flight director analysis and preliminary simulation

    NASA Technical Reports Server (NTRS)

    Johnson, D. E.; Klein, R. E.

    1974-01-01

    A control column and trottle flight director display system is synthesized for use during flight through severe turbulence. The column system is designed to minimize airspeed excursions without overdriving attitude. The throttle system is designed to augment the airspeed regulation and provide an indication of the trim thrust required for any desired flight path angle. Together they form an energy management system to provide harmonious display indications of current aircraft motions and required corrective action, minimize gust upset tendencies, minimize unsafe aircraft excursions, and maintain satisfactory ride qualities. A preliminary fixed-base piloted simulation verified the analysis and provided a shakedown for a more sophisticated moving-base simulation to be accomplished next. This preliminary simulation utilized a flight scenario concept combining piloting tasks, random turbulence, and discrete gusts to create a high but realistic pilot workload conducive to pilot error and potential upset. The turbulence director (energy management) system significantly reduced pilot workload and minimized unsafe aircraft excursions.

  15. Bounded excursion stable gravastars and black holes

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

    Rocha, P; Miguelote, A Y; Chan, R

    2008-06-15

    Dynamical models of prototype gravastars were constructed in order to study their stability. The models are the Visser-Wiltshire three-layer gravastars, in which an infinitely thin spherical shell of stiff fluid divides the whole spacetime into two regions, where the internal region is de Sitter, and the external one is Schwarzschild. It is found that in some cases the models represent the 'bounded excursion' stable gravastars, where the thin shell is oscillating between two finite radii, while in other cases they collapse until the formation of black holes occurs. In the phase space, the region for the 'bounded excursion' gravastars ismore » very small in comparison to that of black holes, but not empty. Therefore, although the possibility of the existence of gravastars cannot be excluded from such dynamical models, our results indicate that, even if gravastars do indeed exist, that does not exclude the possibility of the existence of black holes.« less

  16. All-optical gain-clamped wideband serial EDFA with ring-shaped laser

    NASA Astrophysics Data System (ADS)

    Lu, Yung-Hsin; Chi, Sien

    2004-01-01

    We experimentally investigate the static and dynamic properties of all-optical gain-clamped wideband (1530-1600 nm) serial erbium-doped fiber amplifier with a single ring-shaped laser, which consists of a circulator and a fiber Bragg grating at the output end. The lasing light passing through the second stage is intentionally blocked at the output end by a C/L-band wavelength division multiplexer owning the huge insertion loss, and thus, the copropagating ring-laser light is formed by the first stage. This design can simultaneously clamp the gains of 1547 and 1584 nm probes near 14 dB and shows the same dynamic range of input power up to -4 dBm for conventional band and long-wavelength band. Furthermore, the transient responses of 1551 and 1596 nm surviving channels exhibit small power excursions (<0.54 dB) as the total saturating tone with -2 dBm is modulated on and off at 270 Hz.

  17. Biomechanical effect of latissimus dorsi tendon transfer for irreparable massive cuff tear.

    PubMed

    Oh, Joo Han; Tilan, Justin; Chen, Yu-Jen; Chung, Kyung Chil; McGarry, Michelle H; Lee, Thay Q

    2013-02-01

    The purpose of this study was to determine the biomechanical effects of latissimus dorsi transfer in a cadaveric model of massive posterosuperior rotator cuff tear. Eight cadaveric shoulders were tested at 0°, 30°, and 60° of abduction in the scapular plane with anatomically based muscle loading. Humeral rotational range of motion and the amount of humeral rotation due to muscle loading were measured. Glenohumeral kinematics and contact characteristics were measured throughout the range of motion. After testing in the intact condition, the supraspinatus and infraspinatus were resected. The cuff tear was then repaired by latissimus dorsi transfer. Two muscle loading conditions were applied after latissimus transfer to simulate increased tension that may occur due to limited muscle excursion. A repeated-measures analysis of variance was used for statistical analysis. The amount of internal rotation due to muscle loading and maximum internal rotation increased with massive cuff tear and was restored with latissimus transfer (P < .05). At maximum internal rotation, the humeral head apex shifted anteriorly, superiorly, and laterally at 0° of abduction after massive cuff tear (P < .05); this abnormal shift was corrected with latissimus transfer (P < .05). However, at 30° and 60° of abduction, latissimus transfer significantly altered kinematics (P < .05) and latissimus transfer with increased muscle loading increased contact pressure, especially at 60° of abduction. Latissimus dorsi transfer is beneficial in restoring humeral internal/external rotational range of motion, the internal/external rotational balance of the humerus, and glenohumeral kinematics at 0° of abduction. However, latissimus dorsi transfer with simulated limited excursion may lead to an overcompensation that can further deteriorate normal biomechanics, especially at higher abduction angles. Published by Mosby, Inc.

  18. On the Response of a Nonlinear Structure to High Kurtosis Non-Gaussian Random Loadings

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A.; Przekop, Adam; Turner, Travis L.

    2011-01-01

    This paper is a follow-on to recent work by the authors in which the response and high-cycle fatigue of a nonlinear structure subject to non-Gaussian loadings was found to vary markedly depending on the nature of the loading. There it was found that a non-Gaussian loading having a steady rate of short-duration, high-excursion peaks produced essentially the same response as would have been incurred by a Gaussian loading. In contrast, a non-Gaussian loading having the same kurtosis, but with bursts of high-excursion peaks was found to elicit a much greater response. This work is meant to answer the question of when consideration of a loading probability distribution other than Gaussian is important. The approach entailed nonlinear numerical simulation of a beam structure under Gaussian and non-Gaussian random excitations. Whether the structure responded in a Gaussian or non-Gaussian manner was determined by adherence to, or violations of, the Central Limit Theorem. Over a practical range of damping, it was found that the linear response to a non-Gaussian loading was Gaussian when the period of the system impulse response is much greater than the rate of peaks in the loading. Lower damping reduced the kurtosis, but only when the linear response was non-Gaussian. In the nonlinear regime, the response was found to be non-Gaussian for all loadings. The effect of a spring-hardening type of nonlinearity was found to limit extreme values and thereby lower the kurtosis relative to the linear response regime. In this case, lower damping gave rise to greater nonlinearity, resulting in lower kurtosis than a higher level of damping.

  19. Optimal design of similariton fiber lasers without gain-bandwidth limitation.

    PubMed

    Li, Xingliang; Zhang, Shumin; Yang, Zhenjun

    2017-07-24

    We have numerically investigated broadband high-energy similariton fiber lasers, demonstrated that the self-similar evolution of pulses can locate in a segment of photonic crystal fiber without gain-bandwidth limitation. The effects of various parameters, including the cavity length, the spectral filter bandwidth, the pump power, the length of the photonic crystal fiber and the output coupling ratio have also been studied in detail. Using the optimal parameters, a single pulse with spectral width of 186.6 nm, pulse energy of 23.8 nJ, dechirped pulse duration of 22.5 fs and dechirped pulse peak power of 1.26 MW was obtained. We believe that this detailed analysis of the behaviour of pulses in the similariton regime may have major implications in the development of broadband high-energy fiber lasers.

  20. A high-efficiency self-powered wireless sensor node for monitoring concerning vibratory events

    NASA Astrophysics Data System (ADS)

    Xu, Dacheng; Li, Suiqiong; Li, Mengyang; Xie, Danpeng; Dong, Chuan; Li, Xinxin

    2017-09-01

    This paper presents a self-powered wireless alarming sensor node (SWASN), which was designed to monitor the occurrence of concerning vibratory events. The major components of the sensor node include a vibration-threshold-triggered energy harvester (VTTEH) that powers the sensor node, a dual threshold voltage control circuit (DTVCC) for power management and a radio frequency (RF) signal transmitting module. The VTTEH generates significant electric energy only when the input vibration reaches certain amplitude. Thus, the VTTEH serves as both the power source and the vibration-event-sensing element for the sensor node. The DTVCC was specifically designed to utilize the limited power supply from the VTTEH to operate the sensor node. Constructed with only voltage detectors and MOSFETs, the DTVCC achieved low power consumption, which was 65% lower compared with the power management circuit designed in our previous work. Meanwhile, a RF transmit circuit was constructed based on the commercially available CC1110-F32 wireless transceiver chip and a compact planar antenna was designed to improve the signal transmission distance. The sensor node was fabricated and was characterized both in the laboratory and in the field. Experimental results showed that the SWASN could automatically send out alarming signals when the simulated concerning event occurred. The waiting time between two consecutive transmission periods is less than 125 s and the transmission distance can reach 1.31 km. The SWASN will have broad applications in field surveillances.

  1. A 3,000 year plant leaf wax D/H record of paleohydrology from Southern California

    NASA Astrophysics Data System (ADS)

    Cheetham, M. I.; Feakins, S. J.

    2011-12-01

    We report a high resolution record of hydrological variability based on plant leaf wax D/H measurements in a sediment core from Zaca Lake, Southern California spanning 3,000 years. Compound specific analysis of the n-alkanoic acid fraction yields a powerful suite of relative abundance and isotope data. Comparison to modern vegetation and sediments offers insights into the source of sedimentary waxes and their D/H signatures. We identify three potential sources of waxes at Zaca: 1) mid to long chains from emergent aquatic plants (C28 max), 2) mid chains from Pinus coulteri (C20-C24 only) and 3) mid to long chains from Quercus agrifolia (C28 and C30 max). We establish that long chains are dominated by Quercus and other terrestrial vegetation, whereas mid chains could have mixed sources. At Zaca, 80% shared variance between mid chain and long chain records suggests both derive from terrestrial plants influenced by a common driver, presumably the isotopic composition of precipitation or relative humidity influences on leaf water enrichment. Dendrogram analysis of molecular abundance variations allows us to flag where vegetation change cannot be ruled out. We therefore infer that regional atmospheric circulation changes drove the sustained negative isotope excursion of > 20% from about 2,700 to 2,000 years BP and superimposed higher frequency 20% variability throughout the record, including a number of large, rapid excursion (>20%, <20 years). The results of ongoing analyses will be presented at the meeting.

  2. Age-related changes in posture response under a continuous and unexpected perturbation.

    PubMed

    Tsai, Yi-Ching; Hsieh, Lin-Fen; Yang, Saiwei

    2014-01-22

    Aging is a critical factor to influence the functional performance during daily life. Without an appropriate posture control response when experiencing an unexpected external perturbation, fall may occur. A novel six-degree-of freedom platform with motion control protocol was designed to provide a real-life simulation of unexpected disturbance in order to discriminate the age-related changes of the balance control and the recovery ability. Twenty older adults and 20 healthy young adults participated in the study. The subjects stood barefoot on the novel movable platform, data of the center of mass (COM) excursion, joint rotation angle and electromyography (EMG) were recorded and compared. The results showed that the older adults had similar patterns of joint movement and COM excursion as the young adults during the balance reactive-recovery. However, larger proximal joint rotation in elderly group induced larger COM sway envelop and therefore loss of the compensatory strategy of posture recovery. The old adults also presented a lower muscle power. In order to keep an adequate joint stability preventing from falling, the EMG activity was increased, but the asymmetric pattern might be the key reason of unstable postural response. This novel design of moveable platform and test protocol comprised the computerized dynamic posturography (CDP) demonstrate its value to assess the possible sensory, motor, and central adaptive impairments to balance control and could be the training tool for posture inability person. © 2013 Elsevier Ltd. All rights reserved.

  3. A tail like no other. The RPC-MAG view of Rosetta's tail excursion at comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Volwerk, Martin; Goetz, Charlotte; Richter, Ingo; Delva, Magda; Ostaszewski, Katharina; Schwingenschuh, Konrad; Glassmeier, Karl-Heinz

    2018-06-01

    Context. The Rosetta Plasma Consortium (RPC) magnetometer (MAG) data during the tail excursion in March-April 2016 are used to investigate the magnetic structure of and activity in the tail region of the weakly outgassing comet 67P/Churyumov-Gerasimenko (67P). Aims: The goal of this study is to compare the large scale (near) tail structure with that of earlier missions to strong outgassing comets, and the small scale turbulent energy cascade (un)related to the singing comet phenomenon. Methods: The usual methods of space plasma physics are used to analyse the magnetometer data, such as minimum variance analysis, spectral analysis, and power law fitting. Also the cone angle and clock angle of the magnetic field are calculated to interpret the data. Results: It is found that comet 67P does not have a classical draped magnetic field and no bi-lobal tail structure at this late stage of the mission when the comet is already at 2.7 AU distance from the Sun. The main magnetic field direction seems to be more across the tail direction, which may implicate an asymmetric pick-up cloud. During periods of singing comet activity the propagation direction of the waves is at large angles with respect to the magnetic field and to the radial direction towards the comet. Turbulent cascade of magnetic energy from large to small scales is different in the presence of singing as without it.

  4. Feasibility of self-structured current accessed bubble devices in spacecraft recording systems

    NASA Technical Reports Server (NTRS)

    Nelson, G. L.; Krahn, D. R.; Dean, R. H.; Paul, M. C.; Lo, D. S.; Amundsen, D. L.; Stein, G. A.

    1985-01-01

    The self-structured, current aperture approach to magnetic bubble memory is described. Key results include: (1) demonstration that self-structured bubbles (a lattice of strongly interacting bubbles) will slip by one another in a storage loop at spacings of 2.5 bubble diameters, (2) the ability of self-structured bubbles to move past international fabrication defects (missing apertures) in the propagation conductors (defeat tolerance), and (3) moving bubbles at mobility limited speeds. Milled barriers in the epitaxial garnet are discussed for containment of the bubble lattice. Experimental work on input/output tracks, storage loops, gates, generators, and magneto-resistive detectors for a prototype device are discussed. Potential final device architectures are described with modeling of power consumption, data rates, and access times. Appendices compare the self-structured bubble memory from the device and system perspectives with other non-volatile memory technologies.

  5. An efficient start-up circuitry for de-energized ultra-low power energy harvesting systems

    NASA Astrophysics Data System (ADS)

    Hörmann, Leander B.; Berger, Achim; Salzburger, Lukas; Priller, Peter; Springer, Andreas

    2015-05-01

    Cyber-physical systems often include small wireless devices to measure physical quantities or control a technical process. These devices need a self-sufficient power supply because no wired infrastructure is available. Their operational time can be enhanced by energy harvesting systems. However, the convertible power is often limited and discontinuous which requires the need of an energy storage unit. If this unit (and thus the whole system) is de-energized, the start-up process may take a significant amount of time because of an inefficient energy harvesting process. Therefore, this paper presents a system which enables a safe and fast start-up from the de-energized state.

  6. Numerical investigations of self- and cross-phase modulation effects in high-power fiber amplifiers (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zunoubi, Mohammad R.; Anderson, Brian; Naderi, Shadi A.; Madden, Timothy J.; Dajani, Iyad

    2017-03-01

    The development of high-power fiber lasers is of great interest due to the advantages they offer relative to other laser technologies. Currently, the maximum power from a reportedly single-mode fiber amplifier stands at 10 kW. Though impressive, this power level was achieved at the cost of a large spectral linewidth, making the laser unsuitable for coherent or spectral beam combination techniques required to reach power levels necessary for airborne tactical applications. An effective approach in limiting the SBS effect is to insert an electro-optic phase modulator at the low-power end of a master oscillator power amplifier (MOPA) system. As a result, the optical power is spread among spectral sidebands; thus raising the overall SBS threshold of the amplifier. It is the purpose of this work to present a comprehensive numerical scheme that is based on the extended nonlinear Schrodinger equations that allows for accurate analysis of phase modulated fiber amplifier systems in relation to the group velocity dispersion and Kerr nonlinearities and their effect on the coherent beam combining efficiency. As such, we have simulated a high-power MOPA system modulated via filtered pseudo-random bit sequence format for different clock rates and power levels. We show that at clock rates of ≥30 GHz, the combination of GVD and self-phase modulation may lead to a drastic drop in beam combining efficiency at the multi-kW level. Furthermore, we extend our work to study the effect of cross-phase modulation where an amplifier is seeded with two laser sources.

  7. Direct detection of cysteine using functionalized BaTiO3 nanoparticles film based self-powered biosensor.

    PubMed

    Selvarajan, Sophia; Alluri, Nagamalleswara Rao; Chandrasekhar, Arunkumar; Kim, Sang-Jae

    2017-05-15

    Simple, novel, and direct detection of clinically important biomolecules have continuous demand among scientific community as well as in market. Here, we report the first direct detection and facile fabrication of a cysteine-responsive, film-based, self-powered device. NH 2 functionalized BaTiO 3 nanoparticles (BT-NH 2 NPs) suspended in a three-dimensional matrix of an agarose (Ag) film, were used for cysteine detection. BaTiO 3 nanoparticles (BT NPs) semiconducting as well as piezoelectric properties were harnessed in this study. The changes in surface charge properties of the film with respect to cysteine concentrations were determined using a current-voltage (I-V) technique. The current response increased with cysteine concentration (linear concentration range=10µM-1mM). Based on the properties of the composite (BT/Ag), we created a self-powered cysteine sensor in which the output voltage from a piezoelectric nanogenerator was used to drive the sensor. The potential drop across the sensor was measured as a function of cysteine concentrations. Real-time analysis of sensor performance was carried out on urine samples by non-invasive method. This novel sensor demonstrated good selectivity, linear concentration range and detection limit of 10µM; acceptable for routine analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Detecting Liquefied Petroleum Gas (LPG) at Room Temperature Using ZnSnO3/ZnO Nanowire Piezo-Nanogenerator as Self-Powered Gas Sensor.

    PubMed

    Fu, Yongming; Nie, Yuxin; Zhao, Yayu; Wang, Penglei; Xing, Lili; Zhang, Yan; Xue, Xinyu

    2015-05-20

    High sensitivity, selectivity, and reliability have been achieved from ZnSnO3/ZnO nanowire (NW) piezo-nanogenerator (NG) as self-powered gas sensor (SPGS) for detecting liquefied petroleum gas (LPG) at room temperature (RT). After being exposed to 8000 ppm LPG, the output piezo-voltage of ZnSnO3/ZnO NW SPGS under compressive deformation is 0.089 V, much smaller than that in air ambience (0.533 V). The sensitivity of the SPGS against 8000 ppm LPG is up to 83.23, and the low limit of detection is 600 ppm. The SPGS has lower sensitivity against H2S, H2, ethanol, methanol and saturated water vapor than LPG, indicating good selectivity for detecting LPG. After two months, the decline of the sensing performance is less than 6%. Such piezo-LPG sensing at RT can be ascribed to the new piezo-surface coupling effect of ZnSnO3/ZnO nanocomposites. The practical application of the device driven by human motion has also been simply demonstrated. This work provides a novel approach to fabricate RT-LPG sensors and promotes the development of self-powered sensing system.

  9. Smart patch piezoceramic actuator issues

    NASA Technical Reports Server (NTRS)

    Griffin, Steven F.; Denoyer, Keith K.; Yost, Brad

    1993-01-01

    The Phillips Laboratory is undertaking the challenge of finding new and innovative ways to integrate sensing, actuation, and the supporting control and power electronics into a compact self-contained unit to provide vibration suppression for a host structure. This self-contained unit is commonly referred to as a smart patch. The interfaces to the smart patch will be limited to standard spacecraft power and possibly a communications line. The effort to develop a smart patch involves both contractual and inhouse programs which are currently focused on miniaturization of the electronics associated with vibrational control using piezoceramic sensors and actuators. This paper is comprised of two distinct parts. The first part examines issues associated with bonding piezoceramic actuators to a host structure. Experimental data from several specimens with varying flexural stiffness are compared to predictions from two piezoelectric/substructure coupling models, the Blocked Force Model and the Uniform Strain Model with Perfect Bonding. The second part of the paper highlights a demonstration article smart patch created using the insights gained from inhouse efforts at the Phillips Laboratory. This demonstration article has self contained electronics on the same order of size as the actuator powered by a voltage differential of approximately 32 volts. This voltage is provided by four rechargeable 8 volt batteries.

  10. When dispositional and role power fit: implications for self-expression and self-other congruence.

    PubMed

    Chen, Serena; Langner, Carrie A; Mendoza-Denton, Rodolfo

    2009-03-01

    Integrating and extending the literatures on social power and person-environment fit, 4 studies tested the hypothesis that when people's dispositional beliefs about their capacity to influence others fit their assigned role power, they are more likely to engage in self-expression-that is, behave in line with their states and traits-thereby increasing their likelihood of being perceived by others in a manner congruent with their own self-judgments (i.e., self-other congruence). In Studies 1-3, dispositionally high- and low-power participants were randomly assigned to play a high- or low-power role in an interaction with a confederate. When participants' dispositional and role power fit (vs. conflicted), they reported greater self-expression (Study 1). Furthermore, under dispositional-role power fit conditions, the confederate's ratings of participants' emotional experiences (Study 2) and personality traits (Study 3) were more congruent with participants' self-reported emotions and traits. Study 4's results replicated Study 3's results using an implicit manipulation of power and outside observers' (rather than a confederate's) ratings of participants. Implications for research on power and person perception are discussed.

  11. A Late Cambrian Carbon Isotope Excursion Recorded in Passive Margin Dolostones of the Central Appalachian Basin, USA.

    NASA Astrophysics Data System (ADS)

    Mackey, J. E.; Stewart, B. W.

    2016-12-01

    A Late Cambrian global positive carbon isotope excursion, known as the SPICE event [1,2] is linked to possible widespread ocean anoxia and enhanced carbon burial [3,4]. We report data from the central Appalachian Conasauga Group from the upper portion of the Middle Cambrian Maryville limestone, through the Late Cambrian Nolichucky shale and Maynardville limestone members. A geochemical, macro-, and micro-scale analyses of core material from southeastern Ohio was carried out to further constrain the timing of oceanic anoxia and trace element geochemistry relative to sediment fluxes occurring at the transition of the Middle to Late Cambrian. The section represents condensed, passive margin shale deposition and carbonate ramp development on the continental shelf of Laurentia. Carbonate sediments (primarily diagenetic dolomite) record a positive δ13C (relative to V-PDB) excursion starting in the upper Nolichucky shale member, reaching its peak (+4.0) in the overlying Maynardville limestone. At this location, there is an offset between the onlap Nolichucky shale deposition and start of the C isotope excursion; this was reported as well in a carbonate section further south of this location [2], on the other side of an extensional feature (Rome Trough) that formed a deep marine basin during Cambrian time. The condensed shale package and relatively low TOC content in our samples is likely due to the combination of a shallow, upslope basin location and isostatic influence on passive margin sedimentation. However, within the Rome Trough, the Nolichucky shale is rich in organic carbon and a recent target of hydrocarbon exploration. The data suggest a possible link between deposition of this shale and the global SPICE event. The robustness of the Late Cambrian δ13C excursion in diagenetically altered sediments and association with hydrocarbon bearing units indicates its utility as a stratigraphic indicator and as a target for exploration. Ongoing geochemical work will focus on trace element and isotopic signatures preserved in the carbonate portion of sediments spanning the C isotope excursion. Refs: [1] Saltzman et al., 1998, Geol. Soc. Am. Bull. 110, 285-297; [2] Glumac and Walker, 1998, J. Sed. Res. 68, 1212-1222; [3] Hurtgen et al., 2009, Earth Planet. Sci. Lett. 281, 288-297; [4] Gill et al., 2011, Nature 469, 80-83.

  12. An explorative, cross-sectional study into abnormal muscular coupling during reach in chronic stroke patients

    PubMed Central

    2010-01-01

    Background In many stroke patients arm function is limited, which can be related to an abnormal coupling between shoulder and elbow joints. The extent to which this can be translated to activities of daily life (ADL), in terms of muscle activation during ADL-like movements, is rather unknown. Therefore, the present study examined the occurrence of abnormal coupling on functional, ADL-like reaching movements of chronic stroke patients by comparison with healthy persons. Methods Upward multi-joint reaching movements (20 repetitions at a self-selected speed to resemble ADL) were compared in two conditions: once facilitated by arm weight compensation and once resisted to provoke a potential abnormal coupling. Changes in movement performance (joint angles) and muscle activation (amplitude of activity and co-activation) between conditions were compared between healthy persons and stroke patients using a repeated measures ANOVA. Results The present study showed slight changes in joint excursion and muscle activation of stroke patients due to shoulder elevation resistance during functional reach. Remarkably, in healthy persons similar changes were observed. Even the results of a sub-group of the more impaired stroke patients did not point to an abnormal coupling between shoulder elevation and elbow flexion during functional reach. Conclusions The present findings suggest that in mildly and moderately affected chronic stroke patients ADL-like arm movements are not substantially affected by abnormal synergistic coupling. In this case, it is implied that other major contributors to limitations in functional use of the arm should be identified and targeted individually in rehabilitation, to improve use of the arm in activities of daily living. PMID:20233402

  13. Quick trips to Mars

    NASA Technical Reports Server (NTRS)

    Hornung, R.

    1991-01-01

    The design of a Mars Mission Vehicle that would have to be launched by two very heavy lift launch vehicles is described along with plans for a mission to Mars. The vehicle has three nuclear engine for rocket vehicle application (NERVA) boosters with a fourth in the center that acts as a dual mode system. The fourth generates electrical power while in route, but it also helps lift the vehicle out of earth orbit. A Mars Ascent Vehicle (MAV), a Mars transfer vehicle stage, and a Mars Excursion Vehicle (MEV) are located on the front end of this vehicle. Other aspects of this research including aerobraking, heat shielding, nuclear thermal rocket engines, a mars mission summary, closed Brayton cycle with and without regeneration, liquid hydrogen propellant storage, etc. are addressed.

  14. Perspectives of Fijian Policymakers on the Obesity Prevention Policy Landscape

    PubMed Central

    Hendriks, Anna-Marie; Delai, Mere Y.; Thow, Anne-Marie; Gubbels, Jessica S.; De Vries, Nanne K.; Kremers, Stef P. J.; Jansen, Maria W. J.

    2015-01-01

    In Fiji and other Pacific Island countries, obesity has rapidly increased in the past decade. Therefore, several obesity prevention policies have been developed. Studies show that their development has been hampered by factors within Fiji's policy landscape such as pressure from industry. Since policymakers in the Fijian national government are primarily responsible for the development of obesity policies, it is important to understand their perspectives; we therefore interviewed 15 policymakers from nine Fijian ministries. By applying the “attractor landscape” metaphor from dynamic systems theory, we captured perceived barriers and facilitators in the policy landscape. A poor economic situation, low food self-sufficiency, power inequalities, inappropriate framing of obesity, limited policy evidence, and limited resource sharing hamper obesity policy developments in Fiji. Facilitators include policy entrepreneurs and policy brokers who were active when a window of opportunity opened and who strengthened intersectoral collaboration. Fiji's policy landscape can become more conducive to obesity policies if power inequalities are reduced. In Fiji and other Pacific Island countries, this may be achievable through increased food self-sufficiency, strengthened intersectoral collaboration, and the establishment of an explicit functional focal unit within government to monitor and forecast the health impact of policy changes in non-health sectors. PMID:26380307

  15. Self-pulsing in a 2 km single-mode fiber with the seed source broadened via WNS phase modulation

    NASA Astrophysics Data System (ADS)

    Zha, Congwen; Sun, Yinhong; Wang, Yanshan; Li, Tenglong; Peng, Wanjing; Ma, Yi; Zhang, Kai

    2018-03-01

    The seed source with spectral linewidth broadening via phase modulation is potential to achieve the higher output power with effective SBS suppression. However, self-pulsing from the amplifier output is harmful. In this work, we study the self-pulsing characteristics in a long single-mode fiber with lower self-pulsing threshold instead of the high power amplifier. We provide a powerful experimental support for the self-pulsing mechanism in high-power narrow-linewidth fiber lasers, which is important for further output power scaling.

  16. Experimental investigation of factors limiting slow axis beam quality in 9xx nm high power broad area diode lasers

    NASA Astrophysics Data System (ADS)

    Winterfeldt, M.; Crump, P.; Wenzel, H.; Erbert, G.; Tränkle, G.

    2014-08-01

    GaAs-based broad-area diode lasers are needed with improved lateral beam parameter product (BPPlat) at high power. An experimental study of the factors limiting BPPlat is therefore presented, using extreme double-asymmetric (EDAS) vertical structures emitting at 910 nm. Continuous wave, pulsed and polarization-resolved measurements are presented and compared to thermal simulation. The importance of thermal and packaging-induced effects is determined by comparing junction -up and -down devices. Process factors are clarified by comparing diodes with and without index-guiding trenches. We show that in all cases studied, BPPlat is limited by a non-thermal BPP ground-level and a thermal BPP, which depends linearly on self-heating. Measurements as a function of pulse width confirm that self-heating rather than bias-level dominates. Diodes without trenches show low BPP ground-level, and a thermal BPP which depends strongly on mounting, due to changes in the temperature profile. The additional lateral guiding in diodes with trenches strongly increases the BPP ground-level, but optically isolates the stripe from the device edges, suppressing the influence of the thermal profile, leading to a BPP-slope that is low and independent of mounting. Trenches are also shown to initiate strain fields that cause parasitic TM-polarized emission with large BPPlat, whose influence on total BPPlat remains small, provided the overall polarization purity is >95%.

  17. Non-Gaussianity and Excursion Set Theory: Halo Bias

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

    Adshead, Peter; Baxter, Eric J.; Dodelson, Scott

    2012-09-01

    We study the impact of primordial non-Gaussianity generated during inflation on the bias of halos using excursion set theory. We recapture the familiar result that the bias scales asmore » $$k^{-2}$$ on large scales for local type non-Gaussianity but explicitly identify the approximations that go into this conclusion and the corrections to it. We solve the more complicated problem of non-spherical halos, for which the collapse threshold is scale dependent.« less

  18. In vivo demonstration of ultrasound power delivery to charge implanted medical devices via acute and survival porcine studies

    PubMed Central

    Radziemski, Leon; Makin, Inder Raj S.

    2015-01-01

    Animal studies are an important step in proving the utility and safety of an ultrasound based implanted battery recharging system. To this end an Ultrasound Electrical Recharging System (USER™) was developed and tested. Experiments in vitro demonstrated power deliveries at the battery of up to 600 mW through 10 – 15 mm of tissue, 50 mW of power available at tissue depths of up to 50 mm, and the feasibility of using transducers bonded to titanium as used in medical implants. Acute in vivo studies in a porcine model were used to test reliability of power delivery, temperature excursions, and cooling techniques. The culminating five-week survival study involved repeated battery charging, a total of 10.5 hours of ultrasound exposure of the intervening living tissue, with an average RF input to electrical charging efficiency of 20%. This study was potentially the first long term cumulative living-tissue exposure using transcutaneous ultrasound power transmission to an implanted receiver in situ. Histology of the exposed tissue showed changes attributable primarily due to surgical implantation of the prototype device, and no damage due to the ultrasound exposure. The in vivo results are indicative of the potential safe delivery of ultrasound energy for a defined set of source conditions for charging batteries within implants. PMID:26243566

  19. In vivo demonstration of ultrasound power delivery to charge implanted medical devices via acute and survival porcine studies.

    PubMed

    Radziemski, Leon; Makin, Inder Raj S

    2016-01-01

    Animal studies are an important step in proving the utility and safety of an ultrasound based implanted battery recharging system. To this end an Ultrasound Electrical Recharging System (USER™) was developed and tested. Experiments in vitro demonstrated power deliveries at the battery of up to 600 mW through 10-15 mm of tissue, 50 mW of power available at tissue depths of up to 50 mm, and the feasibility of using transducers bonded to titanium as used in medical implants. Acute in vivo studies in a porcine model were used to test reliability of power delivery, temperature excursions, and cooling techniques. The culminating five-week survival study involved repeated battery charging, a total of 10.5h of ultrasound exposure of the intervening living tissue, with an average RF input to electrical charging efficiency of 20%. This study was potentially the first long term cumulative living-tissue exposure using transcutaneous ultrasound power transmission to an implanted receiver in situ. Histology of the exposed tissue showed changes attributable primarily due to surgical implantation of the prototype device, and no damage due to the ultrasound exposure. The in vivo results are indicative of the potential safe delivery of ultrasound energy for a defined set of source conditions for charging batteries within implants. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Calcium isotope constraints on the end-Permian mass extinction

    PubMed Central

    Payne, Jonathan L.; Turchyn, Alexandra V.; Paytan, Adina; DePaolo, Donald J.; Lehrmann, Daniel J.; Yu, Meiyi; Wei, Jiayong

    2010-01-01

    The end-Permian mass extinction horizon is marked by an abrupt shift in style of carbonate sedimentation and a negative excursion in the carbon isotope (δ13C) composition of carbonate minerals. Several extinction scenarios consistent with these observations have been put forward. Secular variation in the calcium isotope (δ44/40Ca) composition of marine sediments provides a tool for distinguishing among these possibilities and thereby constraining the causes of mass extinction. Here we report δ44/40Ca across the Permian-Triassic boundary from marine limestone in south China. The δ44/40Ca exhibits a transient negative excursion of ∼0.3‰ over a few hundred thousand years or less, which we interpret to reflect a change in the global δ44/40Ca composition of seawater. CO2-driven ocean acidification best explains the coincidence of the δ44/40Ca excursion with negative excursions in the δ13C of carbonates and organic matter and the preferential extinction of heavily calcified marine animals. Calcium isotope constraints on carbon cycle calculations suggest that the average δ13C of CO2 released was heavier than -28‰ and more likely near -15‰; these values indicate a source containing substantial amounts of mantle- or carbonate-derived carbon. Collectively, the results point toward Siberian Trap volcanism as the trigger of mass extinction. PMID:20421502

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